Patent Application
20230184836
The present invention relates to an analysis device, an analysis system, and an analysis method.
Conventionally, there is known a system that analyzes characteristics such as a maximum capacity of a battery (also referred to as full charge capacity) (see, for example, Patent Document 1). Patent Document 1: Japanese Patent No. 6123844
For analyzing battery characteristics with high accuracy, it is necessary to mount a high-performance analysis system in each battery.
For solving the problem described above, according to a first aspect of the present invention, a battery module analysis device is provided. The analysis device may include a data acquisition unit configured to acquire, via a network, analysis data including measurement data obtained by measuring characteristics related to charging and discharging of one or more battery cells included in one or more battery modules and identification data for identifying at least one of the battery modules or the battery cells. The analysis device may include a data analysis unit configured to analyze characteristics related to a charging capacity of at least one of the battery cells, based on the analysis data acquired by the data acquisition unit. The analysis device may include a data transmission unit configured to transmit transmission data corresponding to an analysis result obtained by the data analysis unit via the network.
The data acquisition unit may be configured to acquire the identification data in which module identification data for identifying the battery modules and cell identification data for identifying the battery cells are associated with each other. The data analysis unit may be configured to analyze the characteristics related to the charging capacity of the battery cell for each of the battery modules.
The analysis device may further include an analysis data recording unit configured to record the measurement data acquired by the data acquisition unit over time, in association with the identification data.
The data analysis unit may be configured to allocate, based on a history of the measurement data corresponding to a same piece of the identification data, a new piece of the identification data to the battery cell corresponding to the same piece of the identification data.
The data analysis unit may be configured to generate control data for controlling the battery cell based on the analysis result. The data transmission unit may be configured to transmit the transmission data including the control data.
The data analysis unit may be configured to calculate a remaining capacity of each of the battery cells in each of the battery modules based on the measurement data. The data analysis unit may be configured to generate the control data for discharging at least one of the battery cells in which the remaining capacity is not smallest to reduce a difference between the remaining capacity of the at least one of the battery cells and the remaining capacity of the battery cell in which the remaining capacity is smallest.
The data analysis unit may be configured to generate replacement time data indicating a time to replace the battery cell based on the analysis result. The data transmission unit may be configured to transmit the transmission data including the replacement time data.
The data analysis unit may be configured to generate failure data indicating a failure of the battery cell based on the analysis result. The data transmission unit may be configured to transmit the transmission data including the failure data.
The data analysis unit may be configured to analyze the characteristics related to the charging capacity of the battery cell based on derivation characteristics of capacitance-voltage characteristics during charging or discharging of the battery cell.
The data acquisition unit may be configured to acquire the analysis data including temperature data indicating a temperature of the battery cell at a time of measuring the capacitance-voltage characteristics. The data analysis unit may be configured to correct the analysis by the derivation characteristics based on the temperature of the battery cell.
The analysis device may further include a reference characteristics recording unit having recorded thereon reference characteristics of the derivation characteristics of each of the battery cells. The reference characteristics may include one or more reference feature points. The data analysis unit may be configured to analyze the battery cell based on a measurement feature point in the derivation characteristics of the battery cell and the one or more reference feature points in the reference characteristics.
The reference characteristics recording unit may be configured to record at least one of the reference characteristics at the charging of the battery cell or the reference characteristics at the discharging of the battery cell. The data analysis unit may be configured to select the reference characteristics to be compared with the derivation characteristics, based on which of data obtained during the charging or data obtained during the discharging the measurement data of the battery cell is.
The data analysis unit may be configured to calculate a deterioration rate of the battery cell based on a deterioration amount of the battery cell calculated from the derivation characteristics.
The data analysis unit may be configured to calculate a measurement interval for measuring data related to the charging and discharging of the battery cell, based on the deterioration rate of the battery cell. The data transmission unit may be configured to transmit the transmission data corresponding to the measurement interval.
The data analysis unit may be configured to calculate, based on a deviation amount of the charging capacities between two or more of the battery cells, the deviation amount being calculated from the derivation characteristics of the two or more of the battery cells, a deviation rate of the charging capacities between the two or more of the battery cells.
The data analysis unit may be configured to calculate the measurement interval for measuring the data related to the charging and discharging of the two or more of the battery cells based on the deviation rate of the two or more of the battery cells. The data transmission unit may be configured to transmit the transmission data corresponding to the measurement interval.
According to a second aspect of the present invention, there is provided an analysis system including: the analysis device according to the first aspect; and an analysis data transmission unit configured to transmit the analysis data to the analysis device via the network.
According to a third aspect of the present invention, a battery module analysis method is provided. The analysis method may include generating measurement data obtained by measuring characteristics related to charging and discharging of one or more battery cells included in one or more battery modules. The analysis method may include transmitting, via a network, analysis data including the measurement data and identification data for identifying at least one of the battery modules or the battery cells. The analysis method may include acquiring the analysis data via the network. The analysis method may include analyzing characteristics related to a charging capacity of at least one of the battery cells, based on the analysis data acquired in the acquiring the analysis data. The analysis method may include transmitting transmission data corresponding to an analysis result obtained in the analyzing the characteristics via the network.
The summary clause does not necessarily describe all necessary features of the embodiments of the present invention. The present invention may also be a sub-combination of the features described above.
Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the claimed invention. In addition, not all of the combinations of features described in the embodiments are essential to the solving means of the invention.
Each of the battery modules 202 includes one or more battery cells 204. The battery cell 204 has a configuration with which electrical power can be generated by the battery cell alone. For example, each of the battery cells 204 includes a negative electrode, a positive electrode, and a body portion that generates electrical power between both electrodes. The battery module 202 may include a plurality of battery cells 204 connected in series. Alternatively, the battery module 202 may include a plurality of battery cells 204 connected in parallel. A group of battery cells 204 electrically connected in series or parallel may be given as a single battery module 202. Alternatively, a group of battery cells 204 accommodated in a common housing may be given as a single battery module 202.
The analysis data transmission unit 200 transmits analysis data for analyzing characteristics of the battery module 202 to the analysis device 100 via the network 12. The analysis data transmission unit 200 may be provided for each battery module 202, or may be provided in common for the plurality of battery modules 202. The analysis data transmission unit 200 may be provided in a housing of the battery module 202. In another example, the analysis data transmission unit 200 may be provided apart from the battery module 202. In this case, it is preferable for the analysis data transmission unit 200 to be provided while being communicable with the battery module 202.
The analysis data includes measurement data obtained by measuring characteristics related to charging and discharging of the one or more battery cells 204 included in the battery module 202. The characteristics related to charging and discharging may be electrical characteristics of the battery cell 204 in at least one of timings including a start of charging, during charging, an end of charging, a start of discharging, during discharging, or an end of discharging of the battery cell 204. The electrical characteristics may include at least one of an interpolar voltage, an output current, a remaining capacity value, or an output resistance of the battery cell 204. Further, the electrical characteristics may include a temporal change of at least one of the interpolar voltage or the output current of the battery cell 204. Furthermore, the electrical characteristics may include a temporal change such as deterioration, of at least one of the remaining capacity value or the output resistance of the battery cell 204. Further, the interpolar voltage described above may be an interpolar voltage of the battery module 202 including the plurality of battery cells 204 connected in series or an interpolar voltage of a unit in which the plurality of battery modules 202 are combined.
The analysis data includes identification data associated with measurement data. The identification data includes at least one of module identification data for identifying the battery module 202 or cell identification data for identifying the battery cell 204. The module identification data may be serial numbers allocated to the plurality of battery modules 202. The cell identification data may be a serial number allocated to the one or more battery cells 204 included in the battery module 202.
The network 12 is, for example, the Internet or a local area network, though is not limited thereto. The network 12 may be a dedicated network for connecting the plurality of analysis data transmission units 200 and the analysis device 100, or may be a general-purpose network for also performing communication other than communication between the analysis data transmission unit 200 and the analysis device 100.
The analysis device 100 acquires analysis data of each of the battery modules 202 via the network 12. The analysis device 100 analyzes characteristics related to a charging capacity of the one or more battery cells 204 included in the battery module 202 based on the analysis data. In the present specification, when not mentioned in particular, a unit of a battery capacity is ampere-hour (Ah). The analysis device 100 may be a device that processes information using a single computer, or may be a device that performs decentralized information processing using a plurality of computers. The characteristics related to the charging capacity may include at least one of a full charge capacity of the battery cell 204, a remaining capacity of the battery cell 204, a measurement value of an internal resistance of the battery cell 204, a temporal change amount of deterioration or the like regarding these characteristics, or a variation amount of these characteristics among the battery cells 204 included in the battery module 202. Note that in the present specification, the full charge capacity or the remaining capacity may be referred to as the charging capacity (or capacity). That is, the charging capacity (or capacity) in the present specification conceptually includes both the full charge capacity and the remaining capacity.
The analysis device 100 may transmit an analysis result to outside. The analysis device 100 may transmit the analysis result to a device including the analysis data transmission unit 200, or may transmit the analysis result to a device different from the analysis data transmission unit 200.
The measurement unit 208 generates measurement data obtained by measuring electrical characteristics of the battery module 202. The measurement unit 208 may include at least one of an ammeter or a voltmeter. The analysis data transmission unit 200 transmits, to the analysis device 100, analysis data including the measurement data generated by the measurement unit 208 and identification data of the battery module 202 or the like.
The battery management device 206 receives transmission data from the analysis device 100. The battery management device 206 may control the battery module 202 based on the received transmission data. Further, the battery management device 206 may also provide information corresponding to the received transmission data to a user of the battery module 202. As an example, the battery management device 206 may charge and discharge each of the battery cells 204 based on the remaining capacity of each of the battery cells 204 indicated in the transmission data. In another example, the transmission data may include control data for controlling each of the battery cells 204 to charge and discharge. Further, the battery management device 206 may provide information related to the capacity of each of the battery cells 204 to the user.
The battery management device 206 may be included in the same device as the analysis data transmission unit 200. In this case, the analysis device 100 may transmit and receive transmission data and analysis data using the same communication path. Further, the battery management device 206 may be a different device from the analysis data transmission unit 200. For example, the analysis data transmission unit 200 may be a device managed by the user who is using the battery module 202, and the battery management device 206 may be a device managed by a provider who provided the battery module 202 to the user. In this case, the analysis device 100 may transmit and receive transmission data and analysis data using different communication paths. In another example, the battery management device 206 and the analysis data transmission unit 200 may both be devices managed by the user, or may both be devices managed by the provider.
The analysis device 100 of the present example includes a data acquisition unit 102, a data analysis unit 104, and a data transmission unit 106. The analysis device 100 may further include an analysis data recording unit 108. The data acquisition unit 102 acquires analysis data via the network 12. The data acquisition unit 102 may record the acquired analysis data in the analysis data recording unit 108. The analysis data recording unit 108 records the analysis data for each identification data.
The data analysis unit 104 analyzes the characteristics related to the charging capacity of at least one of the battery cells 204 based on the analysis data acquired by the data acquisition unit 102. The data analysis unit 104 may sequentially analyze the analysis data acquired by the data acquisition unit 102, or may read the analysis data from the analysis data recording unit 108 and analyze the read data.
The data transmission unit 106 transmits transmission data corresponding to an analysis result obtained by the data analysis unit 104 to the battery management device 206 via the network 12. The data transmission unit 106 may determine a transmission destination of the transmission data based on the identification data included in the analysis data used for the analysis by the data analysis unit 104. For example, the data transmission unit 106 may store therein in advance correspondence information in which the identification data and the transmission destination are associated with each other. Further, the analysis data may also include information that designates a transmission destination of the transmission data. In this case, the battery management device 206 may notify the analysis data transmission unit 200 of the information that designates the transmission destination.
According to the analysis system 10 of the present example, since the analysis device 100 is not provided for each battery module 202, costs of the battery modules 202 can be reduced. Further, performance of the analysis device 100 is improved, and thus an analysis of high accuracy can be performed with ease.
The analysis data includes identification data and measurement data Me. The identification data includes at least one of module identification data Mo or cell identification data Ce. In the analysis data in the example of
The measurement data Me is data for each battery cell 204. The analysis data recording unit 108 may record the measurement data acquired over time by the data acquisition unit 102, in association with the identification data. When the identification data includes the cell identification data Ce, the measurement data Me is associated with the cell identification data Ce. In this case, the data analysis unit 104 analyzes the measurement data Me for each cell identification data Ce, and analyzes the characteristics related to the charging capacities of the individual battery cells 204.
When the identification data does not include the cell identification data Ce, each measurement data Me is associated with common module identification data Mo. In this case, the data analysis unit 104 analyzes each measurement data Me and analyzes the characteristics related to the charging capacities of the battery cells 204. Note that when the analyzed characteristics do not specify which battery cell 204 the characteristics belong to, the data analysis unit 104 analyzes at least one of a maximum value, minimum value, average value, or the like of the capacities of the battery cells 204 included in the battery module 202, for example.
In the example of
The driving time data L may indicate a cumulative driving time of each of the battery cells 204. The driving time may be an elapsed time since the battery cell 204 is started to be used, or may be a cumulative time obtained by accumulating a time during which the battery cell 204 is charged or discharged. Alternatively, the number of charging/discharging times of the battery cell 204 may be used as the driving time. Alternatively, the driving time data L may indicate a cumulative driving time of the battery module 202. The driving time data L may be data for each battery cell 204, or may be common data with respect to the battery cells 204 in the battery module 202.
The transmission data may include identification data. The identification data includes at least one of the module identification data Mo or the cell identification data Ce.
The transmission data may include analysis result data A. The analysis result data A is data related to the capacity of each of the battery cells 204, for example. In another example, the analysis result data A is data indicating at least one of the maximum value, minimum value, or average value of the capacities of the one or more battery cells 204 included in the battery module 202.
The transmission data may include control data Co. The control data Co is data used for controlling charging and discharging of the one or more battery cells 204 included in the battery module 202. The control data Co may designate at least one of a charge amount, a discharge amount, a charge timing, a discharge timing, a charge rate, or a discharge rate of each of the battery cells 204. The data analysis unit 104 may generate the control data Co based on the analysis result on the capacity of each of the battery cells 204. For example, the data analysis unit 104 generates control data Co for reducing capacity variations among the one or more battery cells 204 in the battery module 202. The data analysis unit 104 may generate the control data Co when a difference between a maximum value and minimum value of remaining capacities of the plurality of battery cells 204 included in the battery module 202 becomes equal to or larger than a predetermined threshold value. Accordingly, it is possible to suppress a situation where capacity variations among the battery cells 204 become too large.
The transmission data may include replacement time data R. The data analysis unit 104 may calculate a time to replace each of the battery cells 204 based on the analysis result on the capacity of each of the battery cells 204. As an example, the data analysis unit 104 may calculate a deterioration rate of each of the battery cells 204 based on a history of measurement data recorded in the analysis data recording unit 108, and estimate a replacement time based on the deterioration rate. The deterioration of the battery cell 204 can be calculated from deterioration of, for example, the full charge capacity, the interpolar voltage, the output current, or the like. The data analysis unit 104 may calculate a time at which the characteristics of the battery cell 204 fall below a predetermined reference value, as the replacement time of the battery cell 204. The replacement time data R may be data for each battery cell 204. In another example, the replacement time data R may be data for each battery module 202. In this case, of the replacement times of the battery cells 204 included in the battery module 202, the data analysis unit 104 may use the earliest replacement time as the replacement time of the battery module 202.
The transmission data may include failure data F. The data analysis unit 104 may judge whether a failure has occurred in each of the battery cells 204 based on the analysis result on the capacity of each of the battery cells 204. As an example, the data analysis unit 104 judges whether a failure has occurred in each of the battery cells 204 based on a temporal change of the characteristics such as the full charge capacity, of each of the battery cells 204. The data analysis unit 104 may judge that a failure has occurred in the battery cell 204 when a difference between a characteristics value calculated last time and a characteristics value calculated this time exceeds a predetermined reference value. The failure data F may be data for each battery cell 204. In another example, the failure data F may be data for each battery module 202. In this case, the data analysis unit 104 may judge that a failure has occurred in the battery module 202 when a failure occurs in any of the battery cells 204 included in the battery module 202.
The transmission data may include at least one of the analysis result data, the control data, the replacement time data, or the failure data. The transmission data may also include data other than these.
As shown in the diagram of
The plurality of battery cells 204 of the present example are charged simultaneously. Therefore, when variations are caused in the remaining capacities, charging only by an amount corresponding to the battery cell 204 having a smallest available capacity is carried out in each of the battery cells 204, and thus not all the battery cells 204 can be charged to the upper limit max. Similarly, when the plurality of battery cells 204 are simultaneously discharged with respect to loads thereof, each of the battery cells 204 can be discharged only by an amount corresponding to the battery cell 204 having the smallest remaining capacity, and thus not all the battery cells 204 can be discharged to the lower limit min. Therefore, effective capacities of the plurality of battery cells 204 decrease according to a variation amount of the remaining capacities.
The analysis device 100 may analyze the remaining capacity of each of the battery cells 204. The battery management device 206 may charge and discharge each of the battery cells 204 and adjust a cell balance so that the variations in the remaining capacities of the battery cells 204 are reduced. Note that in the present example, the battery cells 204 are discharged to adjust a cell balance. For example, in
The reference characteristics recording unit 110 records predetermined reference characteristics. The data analysis unit 104 analyzes the capacity of the battery cell 204 based on the characteristics calculated from the measurement data and the reference characteristics.
The measurement unit 208 of the present example measures the capacitance-voltage characteristics within a predetermined measurement range of an estimated remaining capacity Q. The measurement range is a part of a range of the estimated remaining capacity from the lower limit min to the upper limit max. It is preferable for the measurement range not to include the lower limit min and upper limit max of the estimated remaining capacity. Accordingly, the measurement unit 208 can measure the capacitance-voltage characteristics while avoiding a situation where the battery cells 204 are close to an overcharged state or an over-discharged state. A size of the measurement range may be half or less or ¼ or less of the size of the range from the lower limit min to the upper limit max. By reducing the size of the measurement range, the capacitance-voltage characteristics can be acquired in a short time, and the capacitance-voltage characteristics are acquired easily even during an actual operation of the battery module 202. Further, by reducing the size of the measurement range, it becomes easy to measure, even in a state where there are variations in the remaining capacities of the plurality of battery cells 204, the capacitance-voltage characteristics without causing overcharging or over-discharging of each of the battery cells 204.
For example, when the battery cell 204 is a lithium battery, lithium ions move between the positive electrode and the negative electrode during charging and discharging. Lithium ions are inserted into each electrode active material (also referred to as reduction) or lithium ions are desorbed (also referred to as oxidization), with the result that a crystal structure of the electrode active material changes. This change in the crystal structure is called “phase transition”, which is a phenomenon that occurs near a potential unique to the electrode active material defined electrochemically. By the phase transition phenomenon, peaks appear at predetermined positions in the reference characteristics.
As described above, it is possible to determine the capacitance-voltage characteristics of the battery cell 204 according to the type of the electrode active material, and also determine the reference characteristics as derivation characteristics thereof. The reference characteristics may be acquired by premeasuring characteristics of one or more battery cells as a reference. Alternatively, the reference characteristics may be acquired in advance by a simulation. A method of acquiring the reference characteristics may be similar to that described in Patent Document 1.
As shown in
The measurement unit 208 may measure the characteristics of the battery cell 204 within a measurement range including any of the reference feature points (i.e., range of estimated remaining capacity). The position of each reference feature point may be notified to the battery management device 206 from the analysis device 100. Further, the analysis device 100 may notify the battery management device 206 of the measurement range including any of the reference feature points. By acquiring the measurement data within the measurement range, a measurement feature point corresponding to the reference feature point is included in the derivation characteristics of the measurement data.
The data analysis unit 104 may analyze the capacity of the battery cell 204 based on the measurement feature point in the derivation characteristics of the battery cell 204 and the reference feature point in the reference characteristics. As described above, the data analysis unit 104 may perform a parallel shift of the derivation characteristics such that the position of the measurement feature point and the position of the reference feature point match.
Although the remaining capacity of the battery cell 204 has been analyzed in the present example, the data analysis unit 104 may also analyze a full charge capacity of the battery cell 204. In this case, the data analysis unit 104 may use the derivation characteristics obtained by differentiating the capacitance-voltage characteristics by a voltage. Further, the reference characteristics recording unit 110 may record the reference characteristics corresponding to the derivation characteristics. The data analysis unit 104 may adjust at least one of the position or amplitude of the reference characteristics so that an error with respect to the derivation characteristics becomes minimum. By integrating the adjusted reference characteristics within a predetermined range of a working voltage, the full charge capacity of the battery cell 204 can be calculated. The data analysis unit 104 may calculate the full charge capacity of the battery cell 204 by a method similar to the method disclosed in Patent Document 1. The data analysis unit 104 may calculate a ratio of the remaining capacity to the full charge capacity (also referred to as SOC).
Note that when the analysis data includes temperature data indicating a temperature of the battery cell 204 obtained at a time of measuring the capacitance-voltage characteristics, the data analysis unit 104 may correct the analysis that uses the derivation characteristics, based on the temperature of the battery cell 204. The capacitance-voltage characteristics of the battery cell 204 may fluctuate depending on the temperature of the battery cell 204. The data analysis unit 104 may correct a characteristics fluctuation due to the temperature of the battery cell 204 and analyze the characteristics of the battery cell 204. Specifically, the data analysis unit 104 may correct at least one of the derivation characteristics or the reference characteristics using the temperature. According to the temperature, the data analysis unit 104 may shift the derivation characteristics or the reference characteristics in an axial direction of the remaining capacity. The data analysis unit 104 may correct an amplitude of the derivation characteristics or the reference characteristics according to the temperature. Correction information indicating the way to correct each characteristics according to the temperature of the battery cell 204 may be preset in the data analysis unit 104. The correction information can be generated by premeasuring how the capacitance-voltage characteristics fluctuate according to the temperature fluctuation.
The data analysis unit 104 can analyze the capacity of the battery cell 204 highly accurately by the method described with reference to
An initial step S1001 indicates a state where the remaining capacities of the battery cells 204 vary. Note that in
The measurement unit 208 may also measure the capacitance-voltage characteristics during an actual operation of the battery module 202 in place of the processing of S1002 and S1003. That is, the measurement unit 208 may also measure the voltages and currents of the battery cells 204 while a current is supplied from the battery module 202 to a load or while surplus electrical power of the power generation device is being charged to the battery module 202.
Next, in a discharging step S1004, at least one of the battery cells 204 in which the remaining capacity is not the smallest is discharged, to reduce a difference in the remaining capacities with respect to the battery cell 204 having the smallest remaining capacity. In S1004, all the battery cells 204 except for the battery cell 204 having the smallest remaining capacity may be discharged by the same amount. In the example of
Next, in a discharging step S1005, processing similar to that of the discharging step S1004 is repeated. That is, at least one of the battery cells 204 in which the remaining capacity is not the smallest is discharged so as to reduce a difference in the remaining capacities with respect to the battery cell 204 having the smallest remaining capacity. In the present example, the remaining capacities of the battery cells 204-3 and 204-2 are the smallest. Therefore, in the present example, the battery cell 204-1 is discharged. Also in S1005, the battery cell 204-1 may be discharged such that the remaining capacity of the battery cell 204-1 becomes equal to the smallest remaining capacity.
By repeating the discharging step described in S1004 or S1005, the remaining capacities of all the battery cells 204 can be made equal to one another. Accordingly, the effective capacity of the battery module 202 can be increased.
In S1002 to S1005, it is preferable to control charging and discharging of the battery cells 204 so that the remaining capacity of any of the battery cells 204 does not become the upper limit max and the lower limit min of each of the battery cells 204. Accordingly, it is possible to suppress a situation where the battery cells 204 are over-discharged or overcharged, and suppress deterioration of the battery cells 204 in the processing described with reference to
Note that when the accuracy in analyzing the capacity of the battery cell 204 is low, each of the battery cells 204 may be set to a full charge state for matching the remaining capacities of the battery cells 204. In contrast, by using the method described with reference to
The data analysis unit 104 may select, based on which of data obtained during charging of the battery cell 204 or data obtained during discharging the measurement data Me of the battery cell 204 is, the reference characteristics to be compared with the derivation characteristics calculated from the measurement data Me. That is, when the measurement data Me is measurement data obtained during charging, the data analysis unit 104 selects the reference characteristics during charging. Alternatively, when the measurement data Me is measurement data obtained during discharging, the data analysis unit 104 selects the reference characteristics during discharging. It is preferable for the analysis data to include data that indicates which of the measurement data obtained during charging or the measurement data obtained during discharging the measurement data Me is.
An initial step S1501 shows a state where the remaining capacities of the battery cells 204 vary. Next, in a charging step S1502, each of the battery cells 204 is charged until the battery cell 204-1 having a largest remaining capacity is fully charged.
Next, in a discharging step S1503, the battery cell 204-1 that has been fully charged is discharged. In S1503, the battery cell 204-1 is discharged until the remaining capacity of the battery cell 204-2, which has the largest remaining capacity out of the battery cells 204 excluding the battery cell 204-1, matches the remaining capacity of the battery cell 204-1.
Next, in a charging step S1504, each of the battery cells 204 is charged until the battery cells 204-1 and 204-2 having the largest remaining capacities are fully charged.
Next, in a discharging step S1505, the battery cells 204-1 and 204-2 that have been fully charged are discharged. In S1505, the battery cells 204-1 and 204-2 are discharged until the remaining capacities of the battery cells 204-1 and 204-2 and the remaining capacity of the battery cell 204-3, which has the largest remaining capacity out of the rest of the battery cells 204, match. As described above, by repeating the charging step and the discharging step, the remaining capacities of all the battery cells 204 can be made equal to one another. Accordingly, the effective capacity of the battery module 202 can be increased.
Note that also in the example of
The battery module 202 may further include an ammeter 216 provided in series with respect to the plurality of battery cells 204. The ammeter 216 measures a current flowing through the plurality of battery cells 204. The ammeter 216 functions as a part of the measurement unit 208.
In the battery module 202 of the present example, the individual battery cells 204 can be selected for discharging. Further, when charging the plurality of battery cells 204, the battery management device 206 connects a charging power source to the positive terminal 211 and the negative terminal 212. Therefore, the plurality of battery cells 204 are charged at the same time. According to the method described with reference to
First, in a measurement start step S1101, the data transmission unit 106 causes the battery management device 206 to start a measurement of the characteristics of the battery cells 204. The data transmission unit 106 may transmit transmission data that becomes a trigger to start the measurement via the network 12. The data transmission unit 106 may transmit transmission data that designates the measurement range shown in
Next, in a data acquisition step S1103, the data acquisition unit 102 acquires analysis data from the analysis data transmission unit 200 via the network 12. Next, in a data analysis step S1104, the data analysis unit 104 analyzes characteristics related to the charging capacity of at least one of the battery cells 204 based on the analysis data acquired in the data acquisition step S1103. The data analysis unit 104 of the present example may calculate an error between the estimated remaining capacity of the battery cell 204 estimated by the measurement unit 208 and the remaining capacity calculated by the analysis. Next, in a result transmission step S1105, the data transmission unit 106 transmits transmission data corresponding to the analysis result obtained in the data analysis step S1104 to the battery management device 206 via the network 12. The transmission data of the present example includes correction data for correcting the estimated remaining capacity.
First, analysis device 100 of the present example, in a measurement step S1201, the measurement unit 208 generates measurement data obtained by measuring characteristics related to charging and discharging of one or more battery cells 204 included in the battery module 202. The measurement unit 208 may measure the characteristics of each of the battery cells 204 so as to include the measurement range designated by the transmission data. The battery management device 206 may cause the measurement unit 208 to start the measurement according to the trigger received from the analysis device 100 in the measurement start step S1101 of
When the battery cells 204 are charged and discharged in order to measure the characteristics of the battery cells 204, the measurement unit 208 integrates current values obtained during charging and discharging of the battery cells 204 (S1202). Further, the measurement unit 208 acquires an integrated value of the current values at each timing within a predetermined period (S1203). The measurement unit 208 calculates an estimated value of the remaining capacity at each timing based on the acquired integrated value (S1204). Accordingly, the capacitance-voltage characteristics of the battery cells 204 in the predetermined measurement range can be acquired as shown in
Next, in a first judgment step S1205, the battery management device 206 judges whether a transfer request for analysis data has been received from the analysis device 100. When the transfer request is received, the analysis data transmission unit 200 transmits the analysis data (S1206). When the transfer request is not received, the battery management device 206 performs next processing without performing the processing of S1206.
Next, in a second judgment step S1207, the battery management device 206 judges whether correction data for correcting the estimated remaining capacity has been received from the analysis device 100. When the correction data is received, the battery management device 206 corrects the estimated remaining capacity (S1208). When the correction data is not received, the battery management device 206 repeats the processing from S1201.
The data analysis unit 104 may calculate the deterioration rate of the battery cell 204 based on a change amount of the full charge capacity from a predetermined start point to a current time point. The start point may be set at any timing from the time point the battery cell 204 is started to be used to the current time point. The deterioration rate of the present example is a deterioration amount of the full charge capacity per unit number of charging/discharging times.
The data analysis unit 104 may also estimate the deterioration rate of the full charge capacity from the current time point onward, from an actual measurement value of the temporal change of the full charge capacity. The data analysis unit 104 may use the deterioration rate from a predetermined start point to the current time point, as the deterioration rate from the current time point onward.
In another example, the data analysis unit 104 may estimate the deterioration rate from the current time point onward from the value of the full charge capacity at the current time point. A relationship between the value of the full charge capacity and the deterioration rate from the current time point onward may be provided in advance to the data analysis unit 104. The relationship may be a designed value set by a manufacturer of the battery cells 204, or may be a relationship obtained statistically from performance of the same type of battery cells 204.
The data analysis unit 104 may generate replacement time data indicating a time to replace the battery cell 204 based on the analysis result on the analysis data. For example, the data analysis unit 104 estimates a time at which the full charge capacity falls below a predetermined reference value Qref based on the estimated value of the deterioration rate. The time may be expressed by a time that has elapsed since the current time point (for example, month, day, or time), or may be expressed by the number of charging/discharging times. The data analysis unit 104 may calculate the number of times charging and discharging have been performed per unit time, from the usage history of the battery cell 204. The data analysis unit 104 may calculate an elapsed time corresponding to the replacement time from the calculated relationship between the time and the number of charging/discharging times. The data analysis unit 104 may also generate, when the full charge capacity at the current time point falls below the predetermined reference value Qref, replacement time data indicating that a period before reaching the replacement time is 0 (i.e., replacement should be performed at current time point).
The data analysis unit 104 may estimate the deviation rate from the current time point onward from an actual measurement value of the temporal change of the deviation amount. The data analysis unit 104 may use the deviation rate from a predetermined start point to the current time point, as the deviation rate from the current time point onward.
In another example, the data analysis unit 104 may estimate the deviation rate from the current time point onward from the value of the deviation amount at the current time point. A relationship between the value of the deviation amount and the deviation rate from the current time point onward may be provided in advance to the data analysis unit 104. The relationship may be a designed value set by a manufacturer of the battery cells 204, or may be a relationship obtained statistically from performance of the same type of battery cells 204.
When the variations in the remaining capacities among the battery cells 204 increase due to variations in natural discharge amounts or the like, the effective capacity of the battery module 202 gradually decreases. In the analysis system 10 of the present example, the cell balance processing on the remaining capacities of the battery cells 204, that has been described with reference to
By shortening the time intervals I1, an adjustment amount of the effective capacity in one cell balance processing can be made small. Therefore, it is possible to shorten a time required for the cell balance processing and thus shorten a time during which the battery module 202 cannot be actually operated.
The data analysis unit 104 may adjust the time intervals I based on the deviation rate of the charging capacities of two or more battery cells 204. The data analysis unit 104 may shorten the time intervals I when a difference between the calculated deviation rate and a predetermined designed value becomes large. The data analysis unit 104 may shorten the time intervals I when a tendency of the deviation among the charging capacities of the battery cells 204 changes. The change of the tendency of the deviation is, for example, a case where a deviation of the battery cells 204 different from the past becomes large. The data analysis unit 104 may set the time intervals Ito become shorter as the deviation rate increases. Accordingly, an increase of the adjustment amount in one cell balance processing can be suppressed. In the example of
The data analysis unit 104 calculates measurement intervals to measure data related to the charging and discharging of two or more battery cells 204 according to the time intervals, so that the cell balance processing can be executed at the time intervals. As an example, the measurement interval is equal to the time interval. The data transmission unit 106 transmits transmission data corresponding to the measurement interval. The data transmission unit 106 may transmit transmission data that becomes a trigger for the measurement unit 208 to measure the characteristics of the battery cell 204 at timings corresponding to the measurement intervals. In another example, the data transmission unit 106 may transmit transmission data including data that indicates a length of the measurement intervals. In this case, the battery management device 206 causes the measurement unit 208 to measure the characteristics of the battery cell 204 at cycles corresponding to the measurement intervals. Further, the data analysis unit 104 may generate control data for controlling charging and discharging of the battery cell 204 according to the analysis result on the measurement data, and transmit the control data at timings corresponding to the time intervals.
The data analysis unit 104 may adjust the time intervals I based on the deterioration rate of the battery cell 204. The data analysis unit 104 may shorten the time intervals I when a difference between the calculated deterioration rate and a predetermined designed value becomes large. The data analysis unit 104 may shorten the time intervals I when the tendency of the deterioration of the charging capacities among the battery cells 204 changes. The change of the tendency of the deterioration is, for example, a case where the deterioration of the battery cells 204 different from the past becomes large.
As the battery cell 204 deteriorates, the variations in the remaining capacities of the battery cells 204 are likely to become large. The data analysis unit 104 may shorten the time intervals I as the deterioration rate of the battery cell 204 increases. The data analysis unit 104 may use an average value of the deterioration rates of the battery cells 204 included in the battery module 202, or use a worst value. Accordingly, an increase of the adjustment amount in one cell balance processing can be suppressed.
The reference value of the full charge capacity can be acquired from the reference characteristics of the full charge capacity. The reference characteristics of the full charge capacity are characteristics that show a change of the full charge capacity with respect to the number of charging/discharging times of the battery cell 204. The reference characteristics of the full charge capacity may be a designed value set by the manufacturer of the battery cell 204, or may be a statistical value acquired statistically. The reference characteristics of the battery cell 204 may be recorded in advance in the data analysis unit 104. Note that the data analysis unit 104 may correct the reference characteristics based on a temperature of the battery cell 204, a time during which the battery cell 204 is left in a full charge state or a minimally-charged state, or the like. The data analysis unit 104 may calculate a deviation rate at which the battery cell 204 deviates from the reference characteristics, from the relationship between the number of charging/discharging times and the deviation amount D.
The data analysis unit 104 may adjust the time intervals I described with reference to
Furthermore, the data analysis unit 104 may shorten the time intervals I when a deviation tendency between the characteristics of the battery cell 204 and the reference characteristics changes. For example, the data analysis unit 104 may judge that the deviation tendency has changed when a difference of the measurement value obtained this time from an approximate curve obtained by approximating the measurement values obtained up to last time, becomes equal to or larger than a predetermined value. In the example of
The data analysis unit 104 of the present example generates the failure data based on a temporal change of the full charge capacity Qmax of the battery cell 204. When a decrease amount ΔQ of the full charge capacity calculated from the analysis data obtained this time from the full charge capacity calculated from the analysis data obtained last time exceeds a predetermined reference value, the data analysis unit 104 may judge that a failure has occurred in the battery cell 204. Accordingly, peeling of electrodes or a rapid characteristics change can be detected to be notified to the battery management device 206. Note that the characteristics to be used for judging a failure are not limited to the full charge capacity.
The data analysis unit 104 of the present example detects whether the battery cell 204 has been replaced based on a temporal change of the full charge capacity Qmax of the battery cell 204. When an increase amount +Q of the full charge capacity calculated from the analysis data obtained this time from the full charge capacity calculated from the analysis data obtained last time exceeds a predetermined reference value, the data analysis unit 104 may judge that the battery cell 204 has been replaced. The data analysis unit 104 may also judge that the battery cell 204 has been replaced based on a magnitude of the change of the characteristics other than the full charge capacity, such as the derivation characteristics.
The measurement unit 208 of the present example allocates cell identification data Ce to the measurement data of each of the battery cells 204 based on the position of each of the battery cells 204 in the battery module 202. For example, the measurement unit 208 allocates the cell identification data Ce for each voltmeter 215 shown in
The data analysis unit 104 of the present example allocates new cell identification data Ce to the battery cell 204 corresponding to the same cell identification data Ce, based on a history of measurement data corresponding to the same cell identification data Ce. For example, as described with reference to
The remaining capacity gauge 240 may be mounted in the battery module 202, or may be arranged outside the battery module 202. The remaining capacity gauge 240 displays information related to the notified estimated remaining capacity.
The data analysis unit 104 may compare the estimated remaining capacity of the battery cell 204 notified by the BMS 230 and the analyzed remaining capacity of the battery cell 204 analyzed from the measurement data. The data transmission unit 106 may transmit transmission data including the compared result. Accordingly, it becomes possible to notify the battery management device 206 of whether the estimated remaining capacity displayed by the remaining capacity gauge 240 is correct. The compared result may be a difference between the estimated remaining capacity and the analyzed remaining capacity.
Various embodiments of the present invention may be described with reference to flowcharts and block diagrams, whose blocks may represent (1) steps of processes in which operations are executed or (2) sections of apparatuses responsible for executing operations. Certain steps and sections may be implemented by a dedicated circuit, a programmable circuit supplied together with computer-readable instructions stored on computer-readable media, or processors supplied together with computer-readable instructions stored on computer-readable media. The dedicated circuit may include a digital and/or analog hardware circuit, or may include an integrated circuit (IC) and/or a discrete circuit. The programmable circuit may include a reconfigurable hardware circuit including logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, a memory element such as a flip-flop, a register, a field programmable gate array (FPGA) and a programmable logic array (PLA), and the like.
A computer-readable medium may include any tangible device that can store instructions to be executed by a suitable device, and as a result, the computer-readable medium having instructions stored thereon includes an article of manufacture including instructions which can be executed to create means for performing operations specified in the flowcharts or block diagrams. Examples of the computer-readable medium may include an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, and the like. More specific examples of the computer-readable medium may include a floppy (registered trademark) disk, a diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an electrically erasable programmable read-only memory (EEPROM), a static random access memory (SRAM), a compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a Blu-ray (registered trademark) disk, a memory stick, an integrated circuit card, and the like.
Computer-readable instructions may include assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, JAVA (registered trademark), C++, etc., and conventional procedural programming languages, such as the “C” programming language or similar programming languages.
Computer-readable instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatuses, or to a programmable circuit, locally or via a local area network (LAN), wide area network (WAN) such as the Internet, or the like, to execute the computer-readable instructions to create means for performing operations specified in the flowcharts or block diagrams. Examples of the processor include a computer processor, a processing unit, a microprocessor, a digital signal processor, a controller, a microcontroller, and the like.
The computer 2200 according to the present embodiment includes the CPU 2212, a RAM 2214, a graphics controller 2216, and a display device 2218, which are mutually connected by a host controller 2210. The computer 2200 also includes input/output units such as a communication interface 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive, which are connected to the host controller 2210 via an input/output controller 2220. The computer also includes legacy input/output units such as a ROM 2230 and a keyboard 2242, which are connected to the input/output controller 2220 via an input/output chip 2240.
The CPU 2212 operates according to programs stored in the ROM 2230 and the RAM 2214, thereby controlling each unit. The graphics controller 2216 obtains image data generated by the CPU 2212 on a frame buffer or the like provided in the RAM 2214 or in itself, and causes the image data to be displayed on the display device 2218.
The communication interface 2222 communicates with other electronic devices via a network. The hard disk drive 2224 stores programs and data used by the CPU 2212 in the computer 2200. The DVD-ROM drive 2226 reads the programs or the data from the DVD-ROM 2201, and provides the hard disk drive 2224 with the programs or the data via the RAM 2214. The IC card drive reads programs and data from the IC card, or writes programs and data to the IC card.
The ROM 2230 stores therein a boot program or the like executed by the computer 2200 at the time of activation, or a program depending on the hardware of the computer 2200. The input/output chip 2240 may also connect various input/output units to the input/output controller 2220 via a parallel port, a serial port, a keyboard port, a mouse port, or the like.
The program is provided by a computer-readable medium such as the DVD-ROM 2201 or the IC card. The program is read from a computer-readable medium, installed in the hard disk drive 2224, the RAM 2214, or the ROM 2230 which are also examples of the computer-readable medium, and executed by the CPU 2212. The information processing described in these programs is read by the computer 2200 and provides cooperation between the programs and various types of hardware resources. The apparatus or method may be configured by implementing operations or processing of information according to use of the computer 2200.
For example, in a case where communication is performed between the computer 2200 and an external device, the CPU 2212 may execute a communication program loaded in the RAM 2214 and instruct the communication interface 2222 to perform communication processing on the basis of processing described in the communication program. Under the control of the CPU 2212, the communication interface 2222 reads transmission data stored in a transmission buffer processing area provided in a recording medium such as the RAM 2214, the hard disk drive 2224, the DVD-ROM 2201, or the IC card, transmits the read transmission data to the network, or writes reception data received from the network in a reception buffer processing area or the like provided on the recording medium.
In addition, the CPU 2212 may cause the RAM 2214 to read all or a necessary part of a file or database stored in an external recording medium such as the hard disk drive 2224, the DVD-ROM drive 2226 (DVD-ROM 2201), the IC card, or the like, and may execute various types of processing on data on the RAM 2214. Next, the CPU 2212 writes back the processed data to the external recording medium.
Various types of information such as various types of programs, data, tables, and databases may be stored in a recording medium and subjected to information processing. The CPU 2212 may execute, on the data read from the RAM 2214, various types of processing including various types of operations, information processing, conditional judgement, conditional branching, unconditional branching, information retrieval/replacement, or the like described throughout the present disclosure and specified by instruction sequences of the programs, and writes the results back to the RAM 2214. In addition, the CPU 2212 may search for information in a file, a database, etc., in the recording medium. For example, when a plurality of entries, each having an attribute value of a first attribute associated with an attribute value of a second attribute, are stored in the recording medium, the CPU 2212 may search for an entry matching the condition whose attribute value of the first attribute is designated, from among the plurality of entries, and read the attribute value of the second attribute stored in the entry, thereby obtaining the attribute value of the second attribute associated with the first attribute satisfying the predetermined condition.
The programs or software modules described above may be stored in a computer-readable medium on or near the computer 2200. In addition, a recording medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet can be used as a computer-readable medium, thereby providing a program to the computer 2200 via the network.
While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations and improvements can be added to the above-described embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the invention.
The operations, procedures, steps, and stages of each process performed by an apparatus, system, program, and method shown in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-086223 | May 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/017815 | 5/11/2021 | WO |
