Embodiments described herein relate generally to a battery pack device, an inspection method of a battery pack device, and a computer-readable storage medium.
Recently, a battery pack using a chargeable secondary battery is used in the power system of an electric motor car, hybrid vehicle, power-assisted bicycle, or the like. The battery pack is also usable in the power facility of a home, hospital, factory, or the like.
The battery pack uses a standardized battery module (predetermined output voltage and capacity) as a minimum constitutional unit, and a plurality of battery modules are connected in series or in parallel in many cases. In each battery module, a predetermined number of plural batteries (cells) are connected in series or in parallel. The method of assembling the battery pack using a battery module as a minimum constitutional unit is employed because convenience in handling and storing the battery modules is taken into consideration.
In the battery pack used in the power facility, the plurality of battery modules are combined in series or in parallel in accordance with the order (necessary capacity or voltage) on the load side. In this case, the output voltage or capacity of the battery pack is an integer multiple of the voltage or capacity of the battery module to be used.
Patent Literature 1: Jpn. Pat. Appin. KOKAI Publication No. 2010-80197
However, because of recent diversification of loads, the range of the voltage or capacity requested on the load side does not always become an integer multiple of the voltage or capacity of the battery module to be used.
To solve this problem, the combination of cells in the battery module may be changed, and a plurality of types of battery modules having different output voltages or different capacities may be prepared. The plurality of types of battery modules are combined to assemble a battery pack having requested output voltage and capacity.
However, if a battery pack is formed by selectively combining arbitrary battery modules out of a plurality of types of battery modules having different output voltages or capacities, a new problem arises. That is, since the battery modules are identical in terms of appearance, a combination error occurs. A combination error leads to a so-called connection error, resulting in an accident such as an electric shock or breakage by a high current.
It is an object of the embodiment to provide a battery pack device capable of inspecting whether a plurality of battery modules are normally combined, guaranteeing safe use of the battery modules, and meeting the diversification of voltages and capacities requested on the load side, an inspection method of a battery pack device, and a computer-readable storage medium.
According to an embodiment, a battery pack device includes a plurality of battery modules, a cell detector, and a determiner. Each of the plurality of battery modules stores a plurality of cells. The cell detector detects a cell detection signal representing whether a cell is present or absent at each of a plurality of positions in each battery module. The determiner determines the state of a cell in each battery module based on the cell detection signal detected by the cell detector, and outputs an abnormal signal if the determined state of the cell is abnormal.
The embodiment will now be described with reference to the accompanying drawings. A battery module and a battery pack as the premise of the embodiment will be described first.
When 24 cells are stored, 12 cells are put into one group and connected in series, and two cell groups are arranged in parallel, as shown in
In the example of the battery module 10b shown in
Assume that one cell has a voltage of 3 V and a capacity of 20 Ah. In this case, the battery module 10a (type A) has an output (rated) voltage of 36 V and a capacity of 40 Ah, the battery module 10b (type B) has an output (rated) voltage of 24 V and a capacity of 20 Ah, the battery module 10c (type C) has an output (rated) voltage of 36 V and a capacity of 20 Ah, and the battery module 10d (type D) has an output (rated) voltage of 24 V and a capacity of 40 Ah.
Each of
The battery pack shown in
The battery pack shown in
In each of the above-described battery packs shown in
That is, the battery pack shown in
In this battery pack, a battery pack having an output voltage (3 V×20 cells)=60 V and a capacity (20 Ah×3 columns)=60 Ah can be obtained. In the arm 201, the battery modules 10a and 10d have the same capacity of 40 Ah and can therefore be connected in series without any problem. In the arm 202, the battery modules 10c and 10b have the same capacity of 20 Ah and can therefore be connected in series without any problem. The arms 201 and 202 have the same output voltage of 60 V and can therefore be connected in parallel without any problem.
Note that the management system may include a current detector configured to detect the charge/discharge current of the battery module in addition to or in place of the voltage detector configured to detect the voltage of a cell. The voltage/temperature detector may acquire not only a voltage and a temperature but also a current value and other information.
Information from the communication controller 3a3 or 3b3 is sent to one battery management unit (BMU). A BMU 300 can communicate with the communication controller and grasps the state of the entire battery module (that is, the state of the battery pack) based on the information from the communication controller. The BMU 300 detects the connection state of cells, the voltage and temperature of cells, the battery level of cells, abnormal/normal cells, and the output voltage and output current of the battery module, and controls operation stop, activation, charge, discharge, and the like.
As described above, when various kinds of battery modules are prepared, a plurality of battery modules selected in accordance with the voltage and capacity requested by the load are assembled to form a battery pack. However, caution is needed not to cause a battery module combination error. A combination error can probably occur at the time of battery pack assembly in the factory, maintenance in a repair site, battery module exchange in case of a failure or the like, and battery module reassembly after inspection conducted by removing the battery module.
Referring to
Note that a switch SW1 is configured to disconnect the arms. At the time of assembly, the switch is turned off. If the combination of battery modules has no problem, the switch SW1 is turned on.
In the battery pack shown in
On the other hand, as shown in
In the arm 221 of this battery pack, the total output voltage of the battery modules 10b and 10d is 48 V, the battery module 10b has a capacity of 20 Ah, and the battery module 10d has a capacity of 40 Ah. Hence, the capacities of the battery modules connected in series are different, resulting in mismatching.
In the arm 222, the total output voltage of the battery modules 10c and 10a is 72 V, the battery module 10c has a capacity of 20 Ah, and the battery module 10a has a capacity of 40 Ah. Hence, the capacities of the battery modules connected in series are different, resulting in mismatching. In addition, since the output voltages of the arms 221 and 222 are different, connecting them by a switch SW2 should be avoided, and this mismatching needs to be notified to the user immediately.
As described above, when various kinds of battery modules are prepared, and a plurality of battery modules are assembled in accordance with the voltage and capacity requested by the load, a battery module combination error may occur.
To prevent such an error, this embodiment employs an arrangement and method to be described below in the cell management system.
Note that in this embodiment, four types of battery modules will be described, and an example of a battery pack formed from the four battery modules will be described for the sake of simplicity. A battery pack incorporated in an actual vehicle, electricity facility, or the like is formed by combining more battery modules in series and parallel.
In each battery module, the processor can detect whether a cell is actually stored at each of the cell storage positions 1 to 24 and obtain a cell detection signal.
A transmitting/receiving unit (can be called a gateway) 301 of the BMU 300 can communicate with the communication controller of each battery module. The transmitting/receiving unit 301 can assign identification data to the communication controller of each battery module and collect data from the communication controller of each battery module. The transmitting/receiving unit 301 may be a function implemented by the processor by executing the program stored in the memory 304 using the interface to input/output data from/to each battery module.
Hence, cell detection signals from each battery module are received by the transmitting/receiving unit 301 of the BMU 300.
The cell detection signals include a cell presence signal representing that a cell is present and a cell absence signal representing that a cell is absent. The cell absence signal at this time is set to a value different from the value of an abnormal signal. The cell detection signal is input to a cell detector 302 for each cell detection signal of the battery module as a detection target. The cell detector 302 gives the cell presence signal or cell absence signal to a cell arrangement state determiner 310. The cell detector 302 may be a function implemented by the processor by executing the program stored in the memory 304.
The cell arrangement state determiner 310 recognizes the cell presence signal or cell absence signal of each of the cell arrangement positions (in this example, the cell arrangement positions 1 to 24 as shown in
If the cell arrangement pattern is known, the following determination is possible. That is, the type of the inspection target battery module can be determined from the cell arrangement pattern. The type of the battery module is determined by a battery module type determiner 311. The battery module type determiner 311 determines whether the actual cell arrangement pattern of each battery module matches a cell arrangement pattern registered in the memory 304 in advance. A matching or mismatching determination output is given to an abnormality or normality determiner 318.
In addition, since the rated voltage and capacity of one used cell are known in advance (this information is stored in, for example, the memory 304), the capacity of the inspection target battery module can be determined using the cell detection signals. The capacity of the battery module is determined by a battery module capacity determiner 312. In addition, the number of cells in the inspection target battery module can be determined. The number of cells in the battery module is determined by an intra battery module cell count determiner 313. Furthermore, the output voltage of the inspection target battery module can be determined. The output voltage of the battery module is determined by a battery module voltage determiner 314. Also, the voltage of an arm formed by the inspection target battery module can be determined. The output voltage of the arm is determined by an arm output voltage determiner 315.
When the capacity of each battery module is known, matching of the capacity between the battery modules in each arm can be determined. This determination is done by a matching determiner 316 for the capacity between the battery modules in an arm. When the output voltage of each battery module is known, matching of the voltage between the arms can be determined. This determination is done by a matching determiner 317 for the voltage between the arms.
In the above-described determination processing, an operator 330 also cooperatively performs addition processing of the number of cells, voltage, capacity, and the like. During the determination processing, the switches SW1 and SW2 shown in
The type determination output from the battery module type determiner 311 and the matching or mismatching determination outputs from the matching determiner 316 for the capacity between the battery modules in an arm and the matching determiner 317 for the voltage between the arms are given to the abnormality or normality determiner (abnormality determiner) 318. In accordance with the type determination output and the matching or mismatching determination outputs, the abnormality or normality determiner 318 decides one of abnormality and normality and gives the decided result to a notifier 319. The notifier 319 gives the abnormal or normal signal of the battery module to, for example, a display device 400 and provides it to the user.
The above-described arrangement includes a plurality of embodiments. The first embodiment is directed to a means and method for determining a battery module type and thus determining whether a battery pack is normally assembled.
In this case, as for the cell detection signals from the battery modules, for example, the abnormal value (the value of a cell absence signal) set to the cell absence signal changes between the battery modules, as shown in
The above assignment is done in a mode to detect the absence of cells and the presence of cells. If an abnormality is detected in cell voltage equalizing processing, a voltage measurement mode, or a temperature measurement mode, an abnormal signal (d: value 0xFF) is assigned.
As described above, when the cell absence signal is detected in each battery module, the type of each battery module can be determined based on a pattern signal representing the absence of cells and the presence of cells. Patterns representing the plurality of types of battery modules to be used may be registered in the memory 304 in advance.
As a result, when the presence of a battery module cell arrangement pattern of a type that is not registered in advance is discriminated from the cell arrangement pattern determined from the cell detection signal, the battery module type determiner 311 determines that the current battery pack is abnormal.
Note that in the normal use mode of the battery pack, if an abnormality is determined from the measured voltage or temperature measurement value of a cell, an abnormal signal (d: value 0xFF) is transmitted. The BMU 300 never confuses the operation of determining the absence of cells and the presence of cells with another operation.
The above-described arrangement also includes the following embodiment. That is, as for the cell detection signals from the battery modules, for example, a value (a: 0xAA) is set to the cell absence signal, as shown in
When this rule is employed, the number of present cells and the number of absent cells in each battery module can be grasped.
The absence of cells and the presence of cells in each battery module are determined by the cell arrangement state determiner 310. The battery module capacity determiner 312 determines the capacity of each battery module. The intra battery module cell count determiner 313 determines the number of cells in each battery module. The battery module voltage determiner 314 determines the output voltage of each battery module. The arm output voltage determiner 315 determines the output voltage of each arm. The matching determiner 316 for the capacity between the battery modules in an arm determines matching of the capacity between the battery modules in each arm. The matching determiner 317 for the voltage between the arms determines matching of the voltage between the arms.
The determination methods will be described below in more detail.
(Determination 1) When the number of cells connected in series in each battery module is known, the total number of cells controlled by the BMU 300 is known. (Total number of cells controlled by BMU 300)÷number of parallel battery modules×cell voltage=rated voltage is thus calculated. It is determined whether the result matches (fits) a desired rated voltage.
(Determination 2) To check the voltage in the parallel direction of arms, it is determined whether the numbers of cells in the series direction of the arms match (fit) in all the parallel arms.
(Determination 3) Check on an arm basis: it is determined whether the capacities of all the battery modules in each arm match (fit).
The above-described determinations will be described with reference to the example shown in
In Case of
(Determination 1) (Total number of cells controlled by BMU 300) 60÷number of parallel battery modules 2×cell voltage 3=rated voltage 60 . . . (fit)
(Determination 2) Number of cells in series direction of arm 211: 20, number of cells in series direction of arm 212: 20 . . . (fit)
(Determination 3) In the arm 211, capacity of battery module 10a: 40 Ah, capacity of battery module 10d: 40 Ah . . . (fit), and in the arm 212, capacity of battery module 10c: 20 Ah, capacity of battery module 10b: 20 Ah . . . (fit)
As described above, in the case of
In Case of
(Determination 1) (Total number of cells controlled by BMU 300) 60÷number of parallel battery modules 2×cell voltage 3=rated voltage 60 . . . (fit)
(Determination 2) Number of cells in series direction of arm 221: 16, number of cells in series direction of arm 222: 24 . . . (unfit)
(Determination 3) In the arm 221, capacity of battery module 10b: 40 Ah, capacity of battery module 10d: 20 Ah . . . (unfit), and in the arm 222, capacity of battery module 10c: 40 Ah, capacity of battery module 10a: 20 Ah . . . (unfit)
As described above, in the combination of
The present invention holds even when only determining the type of each battery module as the first embodiment. That is, if an unfitted (unregistered) battery module exists, the user may be notified that the battery pack is abnormal. The user can thus reexamine the battery pack. As the second embodiment, fit/unfit of a battery pack may be determined by determining the rated voltage, the voltage of each arm, and the capacity of each battery module in each arm using the table described with reference to
Furthermore, as the third embodiment, the above-described first and second embodiments may be combined. That is, the type of each battery module is determined using the table described with reference to
According to another aspect of the embodiment of the present invention, it is possible to provide a battery module inspection method characterized by in a predetermined inspection mode, setting error information to a unique value in advance for each battery module type by the processor of the battery module, and causing the battery module to transmit the error information to the BMU, thereby determining the type of the battery module. Here, the BMU internally stores the type of the battery module and the arrangement pattern of battery cells in advance.
In a case where each battery module is diagnosed for maintenance of a cell voltage or cell temperature, if the determiner detects an abnormality of a cell, an abnormal signal of an abnormal value discriminated from the error information can be transmitted.
The present invention is not limited to the above embodiments, and the names of the blocks are not limited to those shown in the drawings as long as they perform equivalent operations. The embodiments also incorporate integrated blocks or divided blocks. The BMU 300 may be provided with circuit boards respectively dedicated to the blocks. Alternatively, the blocks may be implemented by software (program).
While certain embodiments of the inventions have been described, these embodiments have been presented by way of examples only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The appended claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2012-265090 | Dec 2012 | JP | national |
This application is a Continuation application of PCT Application No. PCT/JP2013/082448, filed Dec. 3, 2013 and based upon and claiming the benefit of priority from Japanese Patent Application No. 2012-265090, filed Dec. 4, 2012, the entire contents of all of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2013/082448 | Dec 2013 | US |
Child | 14728835 | US |