This application claims benefit under 35 U.S.C. § 119(a) to Application No. GB1806415.4, filed with the United Kingdom Intellectual Property Office on Apr. 19, 2018, hereby incorporated herein by reference in its entirety.
The protection system 100 is used to protect a battery pack that includes a small number, e.g., five, of battery cells. In order to protect a battery pack that includes more than five battery cells, two or more of the secondary protection modules 102 are used.
However, when the low-side module 202 receives the protection signal 216 from the high-side module 212, the low-side module 202 also delays outputting the protection signal 210 for the preset time interval ΔT1. Thus, there is a time delay ΔT2 that is twice the preset time interval ΔT1 (ΔT2=2*ΔT1) from the detection of an abnormal condition in the battery cells 214 until the protection signal 210 is output. The time delay ΔT2 may be too long, and consequently the protection system 200A may not be able to protect the battery cells 214 in time.
However, because the level shifter includes the resistors R1, R2, R4, R5, R6, and the switches MN1 and MP1, the cost, size, and power consumption of the PCB (printed circuit board) for the protection system 200B are increased.
Thus, a battery protection system that addresses the abovementioned shortcomings would be beneficial.
In an embodiment, a battery protection system includes multiple protection modules. Each protection module includes a set of monitoring terminals, an output terminal, a switching terminal, and detection circuitry coupled to the monitoring terminals, the output terminal, and the switching terminal. The monitoring terminals are operable for monitoring a status of a set of battery cells. The output terminal is operable for outputting a protection signal if an abnormal condition in the battery cells is detected. The switching terminal is operable for receiving a switching signal. In response to the switching signal, the detection circuitry switches from a normal-working mode to a fast-test mode. If an abnormal condition is detected in the normal-working mode, then the detection circuitry delays outputting the protection signal for a first time interval. If the abnormal condition is detected in the fast-test mode, then the detection circuitry delays outputting the protection signal for a second time interval that is less than the first time interval. The protection modules include a first protection module and a second protection module. The switching terminal of the first protection module and a monitoring terminal of the first protection module are coupled to the second protection module and are operable for receiving a protection signal from the output terminal of the second protection module.
Features and advantages of embodiments of the claimed subject matter will become apparent as the following detailed description proceeds, and upon reference to the drawings, wherein like numerals depict like parts, and in which:
Reference will now be made in detail to the embodiments of the present invention. While the invention will be described in conjunction with these embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.
Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention.
An embodiment according to the present invention provides a battery protection system that includes multiple protection modules for protecting multiple sets of battery cells. The protection module can selectively operate in a normal-working mode or a fast-test mode. If an abnormal condition in the battery cells is detected in the normal-working mode, then the protection module can output a protection signal after a first time interval ΔTN (such as, but not limited to, one, two, or four seconds); or if the abnormal condition is detected in the fast-test mode, then the protection module can output the protection signal after a second time interval ΔTF that is less than the first time interval ΔTN. In an embodiment, a first protection module can generate a first protection signal to protect a first set of battery cells, and/or receive a second protection signal from a second protection module to generate the first protection signal to protect a second set of battery cells. Additionally, the second protection signal can control the first protection module to operate in the fast-test mode. As a result, the delay from the detection of an abnormal condition in the second set of battery cells to the output of the first protection signal is approximately equal to the sum of the first and second time intervals, e.g., ΔTN+ΔTF. In an embodiment, the second time interval ΔTF is relatively short (such as, but not limited to, sixteen or thirty-two milliseconds), and therefore the time delay ΔTN+ΔTF is relatively short compared with the time delay ΔT2 for the conventional battery protection system 200A of FIG. 2A. Furthermore, the level shifter in the conventional battery protection system 200B of
In an embodiment, the protection modules 302 and 312 have similar circuit structures and functions. For example, each of the protection modules 302 and 312 can include a set of monitoring terminals (e.g., labeled “BAT1,” “BAT2,” . . . , “BAT5”) operable for monitoring a status of a set of battery cells (e.g., 304 or 314), an output terminal (e.g., labeled “OV”) operable for outputting a protection signal (e.g., SOV1 or SOV2) if an abnormal condition (e.g., an over-voltage condition) in the battery cells is detected, and a switching terminal (e.g., labeled “VCC”) operable for receiving a switching signal. In an embodiment, the switching terminal VCC can also be used as a power input terminal that receives power supply to operate the protection module. Additionally, in an embodiment, each protection module 302/312 includes detection circuitry coupled to the abovementioned terminals. The detection circuitry can determine whether an abnormal condition (e.g., an over-voltage condition) is present according to information received at the monitoring terminals. In response to detecting an abnormal condition, the detection circuitry can generate the protection signal after a predetermined time delay. The detection circuitry can also switch from a normal-working mode to a fast-test mode in response to the switching signal.
More specifically, in an embodiment, to avoid a false indication of an abnormal condition, when the protection module 302 or 312 detects a sign of an abnormal condition in the battery cells, the protection module does not output a protection signal immediately. Instead, the protection module waits for a time interval ΔTN (e.g., one, two, or four seconds). When the time interval ΔTN expires, if the protection module still detects the sign of an abnormal condition, then the protection module confirms that the abnormal condition is present, and generates the protection signal.
In an embodiment, when a protection module (e.g., 302 or 312) is manufactured and packaged into an IC (integrated circuit) package, a series of tests are performed on the protection module to make sure that the protection module works properly. The series of tests are performed in a fast-test mode, in which the time delay ΔTF before outputting the protection signal is relatively short (e.g., sixteen or thirty-two milliseconds).
In an embodiment, a voltage signal (hereinafter, a switching signal) at the switching terminal VCC can control the protection module to selectively operate in a normal-working mode or a fast-test mode. For example, if a voltage level of the switching signal is in a normal operating voltage range of the protection module (e.g., the protection module receives a supply voltage that is in the normal operation voltage range), then the protection module operates in the normal-working mode. If the abnormal condition of the battery cells is detected in the normal-working mode, then the detection circuitry delays outputting the protection signal for a first time interval ΔTN (e.g., one, two, or four seconds). If the switching signal is higher than a preset voltage level, e.g., VBAT5+5V, then the protection module operates in the fast-test mode. “VBAT5” represents a voltage level at the monitoring terminal BAT5. If the abnormal condition of the battery cells is detected in the fast-test mode, then the detection circuitry delays the outputting of the protection signal for a second time interval ΔTF (e.g., sixteen or thirty-two milliseconds) that is less than the first time interval ΔTN.
In the example of
In an embodiment, the monitoring circuit 418 monitors status of a set of cell voltages and generates an indication signal 430 if a cell voltage of the cell voltages is greater than a reference voltage VREF*(RD1+RD2)/RD1. For example, the monitoring circuit 418 can include a set of comparators 422_1, 422_2, . . . , 422_5. Each of the comparators can compare a corresponding signal, e.g., V1, V2, . . . , or V5, indicative of a voltage difference VD's between two adjacent terminals of the monitoring terminals VSS, BAT1, BAT2, . . . , BAT5, with a reference voltage VREF. If the corresponding signal, e.g., V1, V2, . . . , or V5, is greater than the reference voltage VREF, e.g., indicating that the corresponding voltage difference VD's is greater than the reference voltage VREF*(RD1+RD2)/RD1, then the comparator outputs a corresponding signal OV1, OV2, or OV5 to an OR gate 424. Thus, the OR gate 424 outputs an indication signal 430.
In the example of the first protection module 302 in
As mentioned above, in an embodiment, a voltage signal at the first monitoring terminal BAT5 of the first protection module 302 is controlled according to a status of the cell voltages of the second set of battery cells 314. More specifically, with reference to
In an embodiment, a second protection signal SOV2 at the second output terminal OV can be high enough to cause the voltage drop across the resistor ROV to be greater than the reference voltage VREF*(RD1+RD2)/RD1. Thus, if an abnormal condition is present in the second set of battery cells 314, then the first protection module 302 can detect the abnormal condition via the first monitoring terminal BAT5 of the first protection module 302.
Returning to
In an embodiment, if the fast-test detection circuit 432 receives, at the switching terminal VCC, a second protection signal SOV2 from the output terminal OV of the second protection module 312, then the fast-test detection circuit 432 controls the delay circuit 428 to change the predetermined time delay ΔT from the first time interval ΔTN to the second time interval ΔTF. For example, the fast-test detection circuit 432 includes a comparator 432. The comparator 432 can compare a voltage difference between the switching terminal VCC and the first monitoring terminal BAT5 with a threshold voltage VTH, and can generate a result signal TEST_MD to control the delay circuit 428 based on the comparison. In an embodiment, a voltage level of the second protection signal SOV2 is high enough to cause a voltage drop across the resistor RFT, e.g., representing the voltage difference between the terminals VCC and BAT5, to be greater than the threshold voltage VTH.
As a result, in the example of
At step 502, a first protection module 302 monitors a status of a first set of battery cells 304 via a set of monitoring terminals. For example, the first protection module 302 monitors cell voltages of the battery cells 304 and determines whether a cell voltage of a battery cell of the battery cells 304 is greater than a reference voltage. If a cell voltage of the battery cells 304 is greater than a reference voltage, then the first protection module 302 starts to count time. When a predetermined time interval expires, if the cell voltage of the battery cells 304 is still greater than the reference voltage, then the first protection module 302 determines that an abnormal condition, e.g., an over-voltage condition, is present in the battery cells 304.
At step 504, the first protection module 302 outputs, via its first output terminal OV, a first protection signal SOV1 if an abnormal condition, e.g., an over-voltage condition, in the battery cells 304 is detected. In embodiments, the first protection signal is delayed (e.g., see steps 512 and 514).
At step 506, the first protection module 302 receives, at its switching terminal VCC, a switching signal, e.g., SOV2.
At step 508, the first protection module 302 switches from a normal-working mode to a fast-test mode in response the switching signal, e.g., SOV2.
At step 510, the first protection module 302 delays outputting the first protection signal SOV1 for a first time interval ΔTN (e.g., one, two, or four seconds) if the abnormal condition is detected while the first protection module 302 is in the normal-working mode.
At step 512, the first protection module 302 delays outputting the first protection signal SOV1 for a second time interval ΔTF (e.g., sixteen or thirty-two milliseconds), less than the first time interval ΔTN, if the abnormal condition is detected while the first protection module 302 is in the fast-test mode.
At step 514, a second protection module 312 monitors a status of a second set of battery cells 314. For example, the second protection module 312 monitors cell voltages of the battery cells 314 and determines whether a cell voltage of a battery cell of the battery cells 314 is greater than a reference voltage. If a cell voltage of the battery cells 314 is greater than a reference voltage, then the second protection module 312 starts to count time. When a predetermined time interval expires, if the cell voltage of the battery cells 314 is still greater than the reference voltage, then the second protection module 312 determines that an abnormal condition, e.g., an over-voltage condition, is present in the battery cells 314.
At step 516, the second protection module 312 outputs, via its second output terminal OV, a second protection signal SOV2 if an abnormal condition, e.g., an over-voltage condition, in the battery cells 314 is detected.
At step 518, the first protection module 302 receives, at its switching terminal VCC, a signal, e.g., SOV2, from the second output terminal OV of the second protection module 312.
At step 520, the first protection module 302 also receives, at its first monitoring terminal BAT5, the signal, e.g., SOV2, from the second output terminal OV of the second protection module 312.
While the foregoing description and drawings represent embodiments of the present invention, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope of the principles of the present invention as defined in the accompanying claims. One skilled in the art will appreciate that the invention may be used with many modifications of form, structure, arrangement, proportions, materials, elements, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims and their legal equivalents, and not limited to the foregoing description.
Number | Date | Country | Kind |
---|---|---|---|
1806415 | Apr 2018 | GB | national |
Number | Name | Date | Kind |
---|---|---|---|
8219333 | Li | Jul 2012 | B2 |
8450976 | Lipcsei et al. | May 2013 | B2 |
20010026147 | Nakashimo | Oct 2001 | A1 |
20080164881 | Miyamoto | Jul 2008 | A1 |
20080316665 | Masiuk | Dec 2008 | A1 |
20100141219 | Li | Jun 2010 | A1 |
20100264881 | Yin et al. | Oct 2010 | A1 |
20120280572 | Li et al. | Nov 2012 | A1 |
20130119936 | Emori | May 2013 | A1 |
20130163134 | Ji | Jun 2013 | A1 |
20170269163 | Yang et al. | Sep 2017 | A1 |
20190044198 | Kuroda | Feb 2019 | A1 |
Number | Date | Country |
---|---|---|
102315663 | Jan 2012 | CN |
102457086 | May 2012 | CN |
203522160 | Apr 2014 | CN |
205070405 | Mar 2016 | CN |
205724851 | Nov 2016 | CN |
206452101 | Aug 2017 | CN |
107202958 | Sep 2017 | CN |
2005012852 | Jan 2005 | JP |
Number | Date | Country | |
---|---|---|---|
20190326746 A1 | Oct 2019 | US |