Passive equalization circuit and method and energy storage system

Abstract

The invention provides a passive equalization circuit and method and an energy storage system, and relates to the technical field of battery management. The passive equalization circuit comprises N passive equalization modules which are connected with N battery cells, and the N passive equalization modules are in one-to-one correspondence with the N battery cells; n temperature sampling modules, each temperature sampling module in the N temperature sampling modules is placed adjacent to the corresponding passive equalization module in the N passive equalization modules, and the N temperature sampling modules are in one-to-one correspondence with the N passive equalization modules; the input end of the logic gating module is connected with the output ends of the N temperature sampling modules; and the control module is connected with the control ends of the N passive equalization modules and the output end of the logic gating module. According to the invention, the problems of low accuracy of temperature rise positioning and untimely prevention and control of too high temperature rise in the passive equalization process caused by inaccurate temperature sampling of the passive equalization module are solved.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and in particular to a passive balancing circuit, method, and energy storage system. Background Art

[0002] As the capacity of energy storage cells continues to increase, people are beginning to pay attention to the voltage consistency of each cell to avoid a significant drop in the battery capacity of the entire battery pack due to a voltage mismatch within a single cell. Currently, resistors and switches are connected in series between adjacent cells. The resistors discharge the cells, reducing the voltage of cells with higher voltages and achieving passive cell voltage balancing.

[0003] like Figure 9 and Figure 10 As shown, in the related art, a balanced temperature detection unit is provided to detect the temperature of multiple discharge resistors to prevent the discharge resistor temperature from being too high and causing the circuit board to burn, and each balanced temperature detection unit is used to detect the balanced temperature value of multiple discharge resistors. However, due to the small number of temperature detection units, it is difficult to accurately detect the temperature rise of each discharge resistor, resulting in low temperature control accuracy and a safety risk. Summary of the Invention

[0004] The present application aims to solve the problem of low temperature control accuracy during the passive balancing process of battery cells in the prior art or related art.

[0005] To this end, a first aspect of the present application proposes a passive balancing circuit.

[0006] A second aspect of the present application proposes a passive balancing method.

[0007] A third aspect of the present application provides a passive balancing device.

[0008] A fourth aspect of the present application proposes a passive balancing device.

[0009] A fifth aspect of the present application provides a readable storage medium.

[0010] The sixth aspect of the present application proposes an energy storage system.

[0011] In view of this, according to the first aspect of the present application, a passive balancing circuit is proposed, which is applied to an energy storage system. The energy storage system includes a battery module, and the battery module includes N battery cells, where N is an integer greater than 1. The passive balancing circuit includes: N passive balancing modules, which are connected to the N battery cells, and the N passive balancing modules correspond one-to-one to the N battery cells; N temperature sampling modules, each of the N temperature sampling modules is placed adjacent to a corresponding passive balancing module in the N passive balancing modules, and the N temperature sampling modules correspond one-to-one to the N passive balancing modules, wherein the N temperature sampling modules are used to collect N balanced temperature values of the N passive balancing modules; a logic selection module, the input end of the logic selection module is connected to the output end of the N temperature sampling modules; and a control module, the control module is connected to the control end of the N passive balancing modules and the output end of the logic selection module, and the control module is used to control the operating state of the corresponding passive balancing module according to the voltage value of the N battery cells and the N balanced temperature values.

[0012] In an embodiment of the present application, a passive balancing module is provided for each battery cell in the battery module, and each passive balancing module can perform passive balanced discharge on the corresponding battery cell, and a temperature sampling module is provided at the position corresponding to each passive balancing module, that is, the balanced temperature values of N passive balancing modules are collected respectively by N temperature sampling modules, so that the control module can monitor the balanced temperature value of each passive balancing module, thereby avoiding the situation where the passive balancing module temperature is too high and the circuit board is burned due to inaccurate balanced temperature detection, and solving the problems of low accuracy of temperature rise positioning in the passive balancing process and untimely prevention and control of excessive temperature rise due to inaccurate temperature sampling of the passive balancing module.

[0013] In some embodiments, optionally, the passive balancing module includes: a discharge unit connected to the battery cell; a first switch unit arranged between the discharge unit and the battery cell, the first switch unit being used to switch the on-off state of the discharge unit and the first switch unit; wherein the first switch unit is connected to the control module, the control module being used to control the on-off state of the first switch unit to control the operating state of the passive balancing module.

[0014] In an embodiment of the present application, a discharge unit and a first switch unit are provided in the passive balancing module. The first switch unit can be used to control whether the battery cell is connected to the discharge unit, so that when the first switch unit is controlled to be turned on, the target battery cell can be passively balanced and discharged through the discharge unit, thereby improving the voltage consistency between multiple battery cells.

[0015] In some embodiments, optionally, the discharge unit in each passive balancing module and the corresponding temperature sampling module are arranged adjacent to each other on the circuit board.

[0016] In an embodiment of the present application, the passive balancing module and the temperature sampling module are arranged on the same circuit board, and the discharge unit in the passive balancing module and the temperature sampling module are arranged adjacent to each other on the circuit board, that is, the distance between the discharge unit and the temperature sampling module is relatively close, so that the temperature sampling module can accurately collect the equilibrium temperature value of the discharge unit, further improving the accuracy of temperature control of the passive balancing process.

[0017] In some embodiments, optionally, the number of logic gating modules is M, and P input terminals of the M logic gating modules are connected to output terminals of the N temperature sampling modules, where M is an integer greater than 1, and M≤N, M×P≥N.

[0018] In an embodiment of the present application, multiple logic gating modules are set in the passive balancing circuit, each logic gating module is set with multiple input terminals, and the number of all input terminals in the multiple logic gating modules is greater than or equal to the number of temperature sampling modules, thereby ensuring that the balancing temperature value collected by each temperature sampling module can be transmitted to the control module, further ensuring the accuracy of the temperature control of the passive balancing process of the battery cell by the control module.

[0019] In some embodiments, optionally, the control module includes: a front-end analog control unit, a sampling end of the front-end analog control unit is connected to N battery cells, the front-end analog control unit is used to collect the voltage values of the N battery cells, and the output end of the front-end analog control unit is connected to the control end of the passive balancing module; a main control unit, an input end of the main control unit is connected to the output end of the front-end analog control unit and the output ends of N temperature sampling modules, and the output end of the main control unit is connected to the input end of the front-end analog control unit; wherein the main control unit is used to transmit a first control signal to the front-end analog control unit according to the voltage values of the N battery cells and the N balanced temperature values, so that the front-end analog control unit controls the operating state of the passive balancing module in response to the first control signal.

[0020] In an embodiment of the present application, a front-end analog control unit and a main control unit are provided in the control module. The front-end analog control unit can detect the balanced temperature value, and the main control unit can accurately control the operation of the passive balancing module based on the balanced temperature value and the voltage values of N battery cells. The main control unit can not only control the passive balancing process based on temperature, but also detect whether a software fault occurs in the front-end analog control unit, thereby further improving the reliability and safety of the energy storage system.

[0021] In some embodiments, optionally, the control module also includes: a second switch unit, connected to the output end of the N battery cells, the on-off state of the second switch unit is used to control the on-off state of the output path of the N battery cells; a third switch unit, connected between the control end and the ground end of the second switch unit, a trigger unit, the output end of the trigger unit is connected to the control end of the second switch unit, and the input end of the trigger unit is connected to the output end of the main control unit; wherein the main control unit is used to transmit a second control signal to the second switch unit through the trigger unit to control the on-off state of the second switch unit.

[0022] In an embodiment of the present application, the main control unit can drive the on and off states of the second switch unit and the third switch unit through the trigger unit. When the second switch unit and the third switch unit are turned on, the battery relationship system is initialized and powered on to operate normally, and both the front-end analog control unit and the main control unit are powered on and working, further improving the control stability of the energy storage system.

[0023] In some embodiments, optionally, the control module also includes: a constant voltage source unit, the input end of the constant voltage source unit is connected to the second switch unit, the output end of the constant voltage source unit is connected to the input end of the front-end analog control unit, and the constant voltage source unit is used to transmit a power supply signal to the front-end analog control unit.

[0024] In an embodiment of the present application, the constant voltage source unit is used to power the front-end analog control unit. When the second switch unit and the third switch unit are turned on, the constant voltage source unit transmits electrical energy to the front-end analog control unit, thereby providing a stable voltage to the front-end analog control unit, so that the front-end analog control unit is powered on and operates.

[0025] According to the second aspect of the present application, a passive balancing method is proposed, which is applied to the passive balancing circuit in any of the above embodiments. The passive balancing method includes: when the voltage values of N battery cells are obtained, controlling the operation of a target balancing module in N passive balancing modules according to the voltage values of the N battery cells, and the voltage value of the target battery cell corresponding to the target balancing module meets the passive balancing start condition; when the target balancing module is running, obtaining the balancing temperature value of the target balancing module; and controlling the operating state of the target balancing module according to the balancing temperature value of the target balancing module.

[0026] In an embodiment of the present application, a passive balancing module is provided for each battery cell in the battery module, and each passive balancing module can perform passive balanced discharge on the corresponding battery cell, and a temperature sampling module is provided at a position corresponding to each passive balancing module, that is, the balanced temperature values of N passive balancing modules are collected respectively by N temperature sampling modules, so that the control module can monitor the balanced temperature value of each passive balancing module, thereby avoiding the situation where the passive balancing module temperature is too high and the circuit board is burned due to inaccurate balanced temperature detection, and solving the problem of low temperature control accuracy in the passive balancing process due to inaccurate temperature sampling.

[0027] According to the third aspect of the present application, a passive balancing device is proposed, which is applied to the passive balancing circuit in any of the above embodiments. The passive balancing device includes: a control module, which is used to control the operation of a target balancing module in N passive balancing modules according to the voltage values of the N battery cells when the voltage values of the N battery cells are obtained, and the voltage value of the target battery cell corresponding to the target balancing module meets the passive balancing start condition; an acquisition module, which is used to obtain the balanced temperature value of the target balancing module when the target balancing module is running; and the control module is further used to control the operating state of the target balancing module according to the balanced temperature value of the target balancing module.

[0028] In an embodiment of the present application, a passive balancing module is provided for each battery cell in the battery module, and each passive balancing module can perform passive balanced discharge on the corresponding battery cell, and a temperature sampling module is provided at a position corresponding to each passive balancing module, that is, the balanced temperature values of N passive balancing modules are collected respectively by N temperature sampling modules, so that the control module can monitor the balanced temperature value of each passive balancing module, thereby avoiding the situation where the passive balancing module temperature is too high and the circuit board is burned due to inaccurate balanced temperature detection, and solving the problem of low temperature control accuracy in the passive balancing process due to inaccurate temperature sampling.

[0029] According to a fourth aspect of the present application, a passive balancing device is provided. The passive balancing device includes a processor and a memory. The memory stores a program or instruction. When executed by the processor, the program or instruction implements the steps of the passive balancing method described in any of the above technical solutions. Therefore, the passive balancing device has all the beneficial effects of the passive balancing method described in any of the above technical solutions, and will not be further described here.

[0030] According to the fifth aspect of the present application, a readable storage medium is proposed, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the passive balancing method in any of the above-mentioned technical solutions are implemented, thereby having all the beneficial technical effects of the passive balancing method in any of the above-mentioned technical solutions.

[0031] According to the sixth aspect of the present application, an energy storage system is proposed, comprising: a battery module comprising a plurality of battery cells; a battery management system comprising a passive balancing circuit in any of the above technical solutions, which passively balances the charge of a plurality of battery cells in the battery module based on the passive balancing circuit; and / or executes the passive balancing method in any of the above technical solutions, thereby having the passive balancing circuit in any of the above technical solutions; and / or all the beneficial technical effects of the passive balancing method in any of the above technical solutions, which will not be repeated here.

[0032] Additional aspects and advantages of the present application will become apparent in the following description or may be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0034] Figure 1 One of the circuit topology diagrams of a passive balancing circuit provided in some embodiments of the present application is shown;

[0035] Figure 2 A second circuit topology diagram of a passive balancing circuit provided in some embodiments of the present application is shown;

[0036] Figure 3 A schematic diagram of a circuit board layout of a passive equalization circuit provided in some embodiments of the present application is shown;

[0037] Figure 4 One of the flow charts of a passive balancing method provided in some embodiments of the present application is shown;

[0038] Figure 5 FIG2 shows a second flow chart of a passive balancing method provided in some embodiments of the present application;

[0039] Figure 6 One of the structural block diagrams of a passive balancing device is shown in some embodiments of the present application;

[0040] Figure 7 A second structural block diagram of a passive balancing device is shown in some embodiments of the present application;

[0041] Figure 8 A structural block diagram of an energy storage system is shown in some embodiments of the present application;

[0042] Figure 9 shows a topological diagram of a passive balancing circuit in the related art;

[0043] Figure 10A schematic diagram of a circuit board layout of a passive equalization circuit in the related art is shown.

[0044] The reference numerals are as follows:

[0045] 10 battery module, 11 battery cell, 100 passive balancing circuit, 110 passive balancing module, 111 discharge unit, 112 first switch unit, 120 temperature sampling module, 130 logic selection module, 140 control module, 141 front-end analog control unit, 142 main control unit, 143 second switch unit, 144 third switch unit, 145 trigger unit, 146 constant voltage source unit, 150 circuit board. DETAILED DESCRIPTION

[0046] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the features of this embodiment and the embodiments can be combined with each other.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0048] Refer to the following Figures 1 to 8 A passive balancing circuit, method, and energy storage system according to some embodiments of the present application are described.

[0049] According to one embodiment of the present application, Figure 1 FIG1 shows one of the circuit topology diagrams of a passive balancing circuit provided in some embodiments of the present application. Figure 2 FIG2 shows a second circuit topology diagram of a passive balancing circuit provided in some embodiments of the present application, such as Figure 1 and Figure 2As shown, a passive balancing circuit 100 is proposed, which is applied to an energy storage system. The energy storage system includes a battery module 10, and the battery module 10 includes N battery cells 11, where N is an integer greater than 1. The passive balancing circuit 100 includes: N passive balancing modules 110, connected to the N battery cells 11, and the N passive balancing modules 110 correspond to the N battery cells 11 one by one; N temperature sampling modules 120, each temperature sampling module 120 in the N temperature sampling modules 120 is placed adjacent to the corresponding passive balancing module 110 in the N passive balancing modules 110, and the N temperature sampling modules 120 corresponds one-to-one to the N passive balancing modules 110, wherein the N temperature sampling modules 120 are used to collect the N balanced temperature values of the N passive balancing modules 110; the logic selection module 130, the input end of the logic selection module 130 is connected to the output end of the N temperature sampling modules 120; the control module 140, the control module 140 is connected to the control end of the N passive balancing modules 110 and the output end of the logic selection module 130, and the control module 140 is used to control the operating state of the corresponding passive balancing module 110 according to the voltage values of the N battery cells 11 and the N balanced temperature values.

[0050] In this embodiment, the passive balancing circuit 100 is applied to an energy storage system, which includes a battery module 10. The battery module 10 includes N battery cells 11. The battery cell 11 is the smallest energy storage unit in the battery module 10. Since the voltage and capacity of a single battery cell 11 are limited and cannot meet the needs of high-power equipment, the battery module 10 is formed by connecting multiple battery cells 11 in series and in parallel. Multiple battery cells 11 connected in series can increase the voltage of the battery module 10, and multiple battery cells 11 connected in parallel can increase the capacity of the battery module 10.

[0051] In this embodiment, when the battery module 10 is being charged, there may be a problem of voltage inconsistency among the multiple battery cells 11 in the battery module 10. When there is voltage inconsistency among the multiple battery cells 11, the battery capacity of the entire battery module 10 will decrease. In this case, it is necessary to passively balance the battery cells 11 with higher voltages so that the voltage of the higher voltage battery cells 11 is reduced to a level close to that of the remaining battery cells 11, thereby ensuring the consistency of the voltages among the multiple battery cells 11 in the battery module 10. Specifically, the principle of passive balancing is to discharge the battery cells 11 with higher voltages so that the voltage of the higher voltage battery cells 11 is reduced to a level close to that of the remaining battery cells 11 in the battery module 10, thereby reducing the voltage difference among the multiple battery cells 11.

[0052] In this embodiment, the passive balancing circuit 100 includes a passive balancing module 110 corresponding to N battery cells 11, and each passive balancing module 110 is provided with a corresponding temperature sampling module 120. Each passive balancing module 110 is capable of discharging the corresponding battery cell 11 when in operation, and each temperature sampling module 120 is used to collect the equilibrium temperature value of the passive balancing module 110 when the passive balancing module 110 is in operation. Specifically, the passive balancing module 110 generates heat when discharging the battery cell 11. If the heat generated by the passive balancing module 110 is too high, the circuit board 150 will be burned. Therefore, by providing the temperature sampling module 120 at a position adjacent to the passive balancing module 110, the equilibrium temperature value generated by the passive balancing module 110 when in operation is detected by the temperature sampling module 120.

[0053] For example, the passive balancing circuit 100 includes a discharge resistor and a control switch, which can control the connection between the discharge resistor and the battery cell 11. When the control switch is turned on, the discharge resistor is connected to the output terminal of the battery cell 11, and the voltage of the battery cell 11 can be converted into heat energy through the discharge resistor, thereby discharging the battery cell 11.

[0054] For example, the temperature sampling module 120 may be an NTC (Negative Temperature Coefficient) resistance sampling module, i.e., a temperature sensitive resistor, with a temperature measurement range of -50°C to 150°C.

[0055] In this embodiment, a logic gating module 130 is further provided in the passive balancing circuit 100. The input end of the logic gating module 130 is connected to the output end of the N temperature sampling modules 120, and the output end of the logic gating module 130 is connected to the control module 140. The logic gating module 130 can transmit the balanced temperature value collected by the temperature sampling module 120 to the control module 140, so that the control module 140 can monitor the temperature of the N passive balancing modules 110. The control module 140 is used to control the operating status of the passive balancing module 110, that is, when the control module 140 detects that the voltage of a certain battery cell 11 is too high, it can turn on the passive balancing module 110 corresponding to the battery cell 11 with too high voltage to discharge the battery cell 11. When the passive balancing module 110 is running, the balanced temperature value collected by the corresponding temperature sampling module 120 is obtained, and the operating status of the passive balancing module 110 is controlled based on the balanced temperature value, where the operating status includes maintaining operation and stopping operation.

[0056] Specifically, the control module 140 can collect the voltage value of each battery cell 11 and determine whether the voltage value of each battery cell 11 meets the passive balancing start-up condition. When there is a target battery cell that meets the passive balancing start-up condition among the N battery cells 11, the target balancing module corresponding to the target battery cell is controlled to start running. At this time, the target balancing module discharges the target battery cell, the voltage of the target battery cell continues to drop, and the temperature of the target balancing module increases accordingly. The control module 140 obtains the balanced temperature values collected by all temperature sampling modules 120, and extracts the balanced temperature value corresponding to the target balancing module. The operating status of the target balancing module is monitored in real time according to the numerical relationship between the balanced temperature value and the temperature threshold, to avoid the target balancing module from being burned due to excessive temperature during discharge.

[0057] For example, the number of battery cells 11 is 16, and the number of passive balancing modules 110 is also 16. The 16 passive balancing modules 110 are connected one-to-one to the output ends of the 16 battery cells 11, and the number of temperature sampling modules 120 is also 16. The sampling ends of the 16 temperature sampling modules 120 are set corresponding to the 16 passive balancing modules 110, so as to sample the balanced temperature value of each passive balancing module 110.

[0058] like Figure 9 and Figure 10 As shown, in the related art, multiple battery cells are passively and evenly discharged through multiple discharge resistors. The multiple discharge resistors are set in two areas, and each area is provided with a balanced temperature detection unit to detect the temperature. Therefore, the temperature of each discharge resistor cannot be detected separately, resulting in inaccurate temperature control. Figure 9 D1 is a diode and BAT- is the negative pole of the battery cell.

[0059] In the embodiment of the present application, a passive balancing module 110 is provided for each battery cell 11 in the battery module 10, and each passive balancing module 110 can perform passive balanced discharge on the corresponding battery cell 11, and a temperature sampling module 120 is provided at the position corresponding to each passive balancing module 110, that is, the balanced temperature values of N passive balancing modules 110 are respectively collected by N temperature sampling modules 120, so that the control module 140 can monitor the balanced temperature value of each passive balancing module 110, thereby avoiding the situation where the passive balancing module 110 is too high and the circuit board 150 is burned due to inaccurate balanced temperature detection, and solving the problems of low accuracy of temperature rise positioning in the passive balancing process and untimely prevention and control of excessive temperature rise due to inaccurate temperature sampling of the passive balancing module 110.

[0060] like Figure 1 and Figure 2As shown, in some embodiments, optionally, the passive balancing module 110 includes: a discharge unit 111, connected to the battery cell 11; a first switch unit 112, arranged between the discharge unit 111 and the battery cell 11, and the first switch unit 112 is used to switch the on-off state of the discharge unit 111 and the first switch unit 112; wherein, the first switch unit 112 is connected to the control module 140, and the control module 140 is used to control the on-off state of the first switch unit 112 to control the operating state of the passive balancing module 110.

[0061] In this embodiment, the passive balancing module 110 includes a discharge unit 111 and a first switch unit 112. The discharge unit 111 is connected to the output end of the battery cell 11, and the first switch unit 112 is located between the output end of the battery cell 11 and the discharge unit 111. Specifically, the first end of the first switch unit 112 is connected to the positive electrode of the battery cell 11, the second end of the first switch unit 112 is connected to the first end of the discharge unit 111, and the second end of the discharge unit 111 is connected to the negative electrode of the battery cell 11.

[0062] For example, the discharge unit 111 may be a discharge resistor, and the first switch unit 112 may be an electronic switch tube.

[0063] In this embodiment, when the control module 140 detects that the voltage value of the target battery cell meets the passive balancing start-up condition, it controls the first switch unit 112 in the target balancing module to be in the on state. At this time, the discharge unit 111 is connected to the target battery cell, the electric energy of the target battery cell is transmitted to the discharge resistor, and the voltage of the target battery cell continues to decrease.

[0064] For example, the control module 140 detects that the voltage value of the target cell is 3.6V and the voltage values of the other cells 11 are 3.3V. Then, the control module 140 controls the first switch unit 112 corresponding to the target cell to turn on, and the discharge unit 111 continues to generate heat to discharge the target cell.

[0065] In an embodiment of the present application, a discharge unit 111 and a first switch unit 112 are provided in the passive balancing module 110. The first switch unit 112 can be used to control whether the battery cell 11 is connected to the discharge unit 111, so that when the first switch unit 112 is controlled to be turned on, the target battery cell can be passively balanced and discharged through the discharge unit 111, thereby improving the voltage consistency between the multiple battery cells 11.

[0066] Figure 3 FIG. 1 shows a schematic diagram of the layout of a circuit board 150 of a passive equalization circuit 100 provided in some embodiments of the present application. Figure 3As shown, in some embodiments, optionally, the discharge unit 111 in each passive balancing module 110 and the corresponding temperature sampling module 120 are disposed adjacent to each other on the circuit board 150 .

[0067] In the embodiment of the present application, the passive balancing module 110 and the temperature sampling module 120 are arranged on the same circuit board 150, and the discharge unit 111 in the passive balancing module 110 and the temperature sampling module 120 are arranged adjacent to each other on the circuit board, that is, the discharge unit 111 and the temperature sampling module 120 are close to each other, so that the temperature sampling module 120 can accurately collect the equilibrium temperature value of the discharge unit 111, further improving the accuracy of temperature control of the passive balancing process.

[0068] Exemplarily, the discharge unit 111 is a discharge resistor disposed on the circuit board 150 , and the temperature sampling module 120 is a thermistor disposed adjacent to the discharge resistor. The thermistor is close to the discharge resistor, so that the equilibrium temperature value of the discharge resistor can be accurately collected.

[0069] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the number of logic gating modules 130 is M, and P input terminals of the M logic gating modules 130 are connected to the output terminals of N temperature sampling modules 120, where M is an integer greater than 1, and M≤N, M×P≥N.

[0070] In this embodiment, there can be multiple logic gating modules 130, and the input ends of the multiple logic gating modules 130 are connected to the output ends of N temperature sampling modules 120, wherein each input end of the multiple logic gating modules 130 is respectively connected to the output end of a temperature sampling module 120. Therefore, the number M×P of all input ends in the multiple logic gating modules 130 is greater than or equal to the number N of the temperature sampling modules 120, ensuring that the balanced temperature value output by each temperature sampling module 120 can be transmitted to the control module 140 through the logic gating module 130.

[0071] Specifically, the control end of the logic gating module 130 is connected to the control module 140. The control module transmits a gating signal to the logic gating module 130 to determine whether the logic gating module 130 is allowed to transmit the temperature signal corresponding to the collected equilibrium temperature value to the control module 140. It is understandable that the N temperature sampling modules 120 may be separately set in different areas, and the sampling modules in each area correspond to a logic gating module 130, thereby ensuring that the temperature values collected by the temperature collection modules in different areas can all be transmitted to the control module 140 through the logic gating module 130.

[0072] Exemplarily, the number of battery cells 11, the number of passive balancing modules 110, and the number N of temperature sampling modules 120 are all 16, and the 16 temperature sampling modules 120 are arranged in two circuit board 150 areas, the number M of logic gating modules 130 is 2, and the two logic gating modules 130 are respectively arranged in two circuit board 150 areas, and each logic gating module 130 is selected as an 8-in-1 gating module, that is, the number P of input terminals of each logic gating module 130 is 8, and each input terminal of the two logic gating modules 130 is connected to the output terminal of a temperature sampling module 120.

[0073] In an embodiment of the present application, a plurality of logic selection modules 130 are provided in the passive balancing circuit 100, each logic selection module 130 is provided with a plurality of input terminals, and the number of all input terminals in the plurality of logic selection modules 130 is greater than or equal to the number of temperature sampling modules 120, thereby ensuring that the balancing temperature value collected by each temperature sampling module 120 can be transmitted to the control module 140, further ensuring the accuracy of the temperature control of the passive balancing process of the battery cell 11 by the control module 140.

[0074] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the control module 140 includes: a front-end analog control unit 141, a sampling end of the front-end analog control unit 141 is connected to N battery cells 11, the front-end analog control unit 141 is used to collect the voltage values of the N battery cells 11, and the output end of the front-end analog control unit 141 is connected to the control end of the passive balancing module 110; a main control unit 142, an input end of the main control unit 142 is connected to the output end of the front-end analog control unit 141 and the output end of the N temperature sampling modules 120, and the output end of the main control unit 142 is connected to the input end of the front-end analog control unit 141; wherein, the main control unit 142 is used to transmit a first control signal to the front-end analog control unit 141 according to the voltage values of the N battery cells 11 and the N balanced temperature values, so that the front-end analog control unit 141 controls the operating state of the passive balancing module 110 in response to the first control signal.

[0075] In this embodiment, the control module 140 includes a front-end analog control unit 141 and a main control unit 142. The front-end analog control unit 141 is connected to the main control unit 142, that is, the main control unit 142 and the front-end analog control unit 141 can transmit signals. The front-end analog control unit 141 can sample the voltage values of N battery cells 11 and transmit the voltage values of the N battery cells 11 to the main control unit 142. The main control unit 142 can determine whether each battery cell 11 meets the passive balancing start condition based on the voltage values of the N battery cells 11. The input end and output end of the front-end analog control unit 141 are respectively connected to the output end of the main control unit 142 and the control end of the passive balancing module 110. When the main control unit 142 obtains the voltage values of the N battery cells 11 and the N balanced temperature values, it can transmit a first control signal to the front-end analog control unit 141, so that the output end of the front-end analog control unit 141 can output a signal to control whether the passive balancing module 110 is running.

[0076] For example, the passive balancing control process of the control module 140 is described below by taking the front-end analog control unit 141 as an AFE (Analog Front-End) chip and the main control unit 142 as an MCU (Microcontroller Unit) chip as an example:

[0077] The BMS (Battery Management System) system is powered on and initialized to operate normally. The MCU detects that the voltage of the target battery cell is 3.6V, which is too high. The voltages of the other battery cells 11 are all 3.3V, and the voltage difference is 300mV, which meets the passive balancing start condition. The MCU sends instructions to the AFE through the I2C (two-wire) interface communication. The AFE outputs a high-level signal of 3.3V. The first switch unit 112 in the target balancing module corresponding to the target battery cell is enabled and closed. The discharge unit 111 in the target balancing module continues to heat up, and the target battery cell is in a passive balancing state. The MCU detects the 16 balancing temperature values at the discharge units 111 corresponding to the 16 battery cells 11 in real time through two logic selection modules 130. The MCU detects that the balancing temperature value corresponding to the target battery cell is 110°C, which exceeds the temperature threshold of 105°C. The MCU sends a command through the GPIO (General-Purpose Input / Output) port to shut down the main power circuit's charge and discharge MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) switch. It also sends a command to the AFE through the I2C communication interface, causing it to output a low-level signal (0V). The MCU continuously monitors the target cell's corresponding balanced temperature for 30 seconds to see if it gradually decreases and falls below the temperature threshold of 105°C. If the target cell's balanced temperature remains above the 105°C threshold for 30 seconds, the MCU determines that the AFE software function has failed, drives the AFE's enable pin low to 0V, shutting off the AFE's power supply and forcing the AFE to power down and execute the balancing module's overtemperature protection strategy.

[0078] In an embodiment of the present application, a front-end analog control unit 141 and a main control unit are provided in the control module 140. The front-end analog control unit 141 can detect the equilibrium temperature value, and the main control unit 142 can accurately control the operation of the passive balancing module 110 based on the equilibrium temperature value and the voltage values of the N battery cells 11. The main control unit 142 can not only control the passive balancing process based on the temperature, but also detect whether a software fault occurs in the front-end analog control unit 141, thereby further improving the reliability and safety of the energy storage system.

[0079] like Figure 1 and Figure 2As shown, in some embodiments, optionally, the control module 140 also includes: a second switch unit 143, connected to the output end of the N battery cells 11, and the on-off state of the second switch unit 143 is used to control the on-off state of the output path of the N battery cells 11; a third switch unit 144, connected between the control end and the ground end of the second switch unit 143, a trigger unit 145, the output end of the trigger unit 145 is connected to the control end of the second switch unit 143, and the input end of the trigger unit 145 is connected to the output end of the main control unit 142; wherein the main control unit 142 is used to transmit a second control signal to the second switch unit 143 through the trigger unit 145 to control the on-off state of the second switch unit 143.

[0080] In an embodiment of the present application, the main control unit can drive the on and off states of the second switch unit 143 and the third switch unit 144 through the trigger unit 145. When the second switch unit 143 and the third switch unit 144 are turned on, the battery relationship system is initialized and powered on to operate normally, and the front-end analog control unit 141 and the main control unit are both powered on and working, further improving the control stability of the energy storage system.

[0081] Exemplarily, the second switch unit 143 is a PMOS (P-channel Metal-Oxide-SemiconductorField-Effect Transistor) switch, the third switch unit 144 is an NMOS (N-channel Metal-Oxide-SemiconductorField-Effect Transistor) switch, and the trigger unit 145 is a D trigger.

[0082] like Figure 1 and Figure 2 As shown, in some embodiments, optionally, the control module 140 also includes: a constant voltage source unit 146, the input end of the constant voltage source unit 146 is connected to the second switch unit 143, the output end of the constant voltage source unit 146 is connected to the input end of the front-end analog control unit 141, and the constant voltage source unit 146 is used to transmit a power supply signal to the front-end analog control unit 141.

[0083] In an embodiment of the present application, the constant voltage source unit 146 is used to power the front-end analog control unit 141. When the second switch unit 143 and the third switch unit 144 are turned on, the constant voltage source unit 146 transmits electrical energy to the front-end analog control unit 141, thereby providing a stable voltage to the front-end analog control unit 141, so that the front-end analog control unit 141 is powered on and operates.

[0084] According to one embodiment of the present application, Figure 4 FIG. 1 shows one of the flow charts of a passive balancing method provided in some embodiments of the present application, such as Figure 4 As shown, a passive balancing method is proposed, which is applied to the passive balancing circuit in any of the above embodiments. The passive balancing method includes:

[0085] Step 402: When the voltage values of the N battery cells are obtained, control the operation of a target balancing module in the N passive balancing modules according to the voltage values of the N battery cells, and the voltage value of the target battery cell corresponding to the target balancing module meets the passive balancing start condition;

[0086] In this embodiment, the voltage value of each cell is collected and a determination is made as to whether the voltage value of each cell satisfies the passive balancing activation condition. If a target cell that satisfies the passive balancing activation condition exists among the N cells, the target balancing module corresponding to the target cell is controlled to start operating. At this time, the target balancing module discharges the target cell, causing the voltage of the target cell to continuously decrease and the temperature of the target balancing module to increase accordingly.

[0087] Step 404: When the target balancing module is running, obtain the balancing temperature value of the target balancing module;

[0088] Step 406 : Control the operating state of the target balancing module according to the balancing temperature value of the target balancing module.

[0089] In this embodiment, the control module obtains the equilibrium temperature values collected by all temperature sampling modules, and extracts the equilibrium temperature value corresponding to the target equilibrium module. The operating status of the target equilibrium module is monitored in real time according to the numerical relationship between the equilibrium temperature value and the temperature threshold, so as to avoid the circuit board burning caused by the target equilibrium module being too high during discharge.

[0090] In an embodiment of the present application, a passive balancing module is provided for each battery cell in the battery module, and each passive balancing module can perform passive balanced discharge on the corresponding battery cell, and a temperature sampling module is provided at a position corresponding to each passive balancing module, that is, the balanced temperature values of N passive balancing modules are collected respectively by N temperature sampling modules, so that the control module can monitor the balanced temperature value of each passive balancing module, thereby avoiding the situation where the passive balancing module temperature is too high and the circuit board is burned due to inaccurate balanced temperature detection, and solving the problem of low temperature control accuracy in the passive balancing process due to inaccurate temperature sampling.

[0091] In some embodiments, optionally, the operating state of the target balancing module is controlled according to the balancing temperature value of the target balancing module, including: when the balancing temperature value of the target balancing module is greater than or equal to the temperature threshold, controlling the target balancing module to stop operating; when the balancing temperature value of the target balancing module is less than the temperature threshold, controlling the target balancing module to keep operating until the voltage value of the target battery cell meets the passive balancing shutdown condition.

[0092] Among them, the passive balancing shutdown conditions include: the voltage value of the target battery cell is not greater than the voltage values of the remaining battery cells, or the voltage difference between the voltage value of the target battery cell and the voltage values of the remaining battery cells is less than the difference threshold.

[0093] In this embodiment, if the balanced temperature value of the target balancing module in operation is detected to be greater than or equal to a temperature threshold, it is determined that if the discharge unit in the target balancing module continues to operate, it may cause the circuit board to burn. Therefore, the target balancing module is controlled to stop operation, allowing the discharge unit in the target balancing module to gradually cool down. If the balanced temperature value of the target balancing module in operation is detected to be less than the temperature threshold, it is determined that the discharge unit in the target balancing module is at a low temperature and can continue to operate. Therefore, the target balancing module is controlled to remain in operation and the balanced temperature value of the target balancing module is continuously collected and detected.

[0094] Exemplarily, the temperature threshold value ranges from 95° C. to 110° C., and can be specifically selected as 105° C.

[0095] In an embodiment of the present application, a front-end analog control unit and a main control unit are provided in the control module. The front-end analog control unit can detect the balanced temperature value, and the main control unit can accurately control the operation of the passive balancing module based on the balanced temperature value and the voltage values of N battery cells, thereby improving the reliability and safety of the energy storage system.

[0096] In some embodiments, optionally, the control module includes: a front-end analog control unit; when the balancing temperature value of the target balancing module is greater than or equal to the temperature threshold, after controlling the target balancing module to stop running, the passive balancing method also includes: when the target balancing module stops running for a preset time and the balancing temperature value of the target balancing module is less than the temperature threshold, controlling the target balancing module to be in an operating state until the voltage value of the target battery cell meets the passive balancing shutdown condition; when the target balancing module stops running for a preset time and the balancing temperature value of the target balancing module is greater than or equal to the temperature threshold, stopping power supply to the front-end analog control unit.

[0097] In this embodiment, when it is detected that the balanced temperature value is greater than or equal to the temperature threshold and the target balancing module is controlled to stop operating, the balanced temperature value of the target balancing module continues to decrease. When the target balancing module stops operating for a preset period of time, it is determined whether the balanced temperature value of the target balancing module is less than the temperature threshold. If the balanced temperature value is less than the temperature threshold, it is determined that the front-end analog control unit has not failed and the temperature has dropped to a safe range. At this time, the passive balancing process can continue. If the balanced temperature value is still not less than the temperature threshold after the preset period of time, it is determined that the front-end analog control unit may have a software failure. In this case, the front-end analog control unit needs to be powered off and stopped to avoid further failures.

[0098] In an embodiment of the present application, a front-end analog control unit and a main control unit are provided in the control module. The main control unit can not only control the passive balancing process based on temperature, but also detect whether a software fault occurs in the front-end analog control unit, thereby further improving the reliability and safety of the energy storage system.

[0099] In some embodiments, optionally, the passive balancing start-up conditions include: the voltage value of the target battery cell is greater than the voltage values of the remaining battery cells, and the voltage difference between the voltage value of the target battery cell and the voltage value of the remaining battery cells is greater than a difference threshold, wherein the remaining battery cells are the battery cells other than the target battery cell among the N battery cells.

[0100] In an embodiment of the present application, when it is detected that the voltage value of the target battery cell is greater than the voltage values of the remaining battery cells, and the voltage difference between the voltage value of the target battery cell and the voltage value of the remaining battery cells is greater than the difference threshold, it is determined that the passive balancing start-up condition is met. When it is detected that the voltage value of the target battery cell is not greater than the voltage value of the remaining battery cells, or the voltage difference between the voltage value of the target battery cell and the voltage value of the remaining battery cells is less than the difference threshold, it is determined that the passive balancing start-up condition is not met. By setting the passive balancing start-up condition, it is possible to accurately determine whether it is necessary to perform a passive balancing action on the target battery cell, thereby improving the voltage consistency between the battery cells in the battery management system.

[0101] Exemplarily, the difference threshold value ranges from 100 mV to 500 mV, and can be specifically selected as 300 mV.

[0102] According to one embodiment of the present application, Figure 5 FIG2 shows a second flow chart of a passive balancing method provided in some embodiments of the present application. Figure 5 As shown, passive equalization methods include:

[0103] Step 501: The battery management system is powered on and initialized and the system operates normally. The main control unit drives the second switch unit and the third switch unit to conduct through the trigger module.

[0104] Step 502: The main control unit detects that the voltage of the target battery cell is too high and transmits a first control signal to the front-end analog control unit;

[0105] Step 503: The front-end analog control unit outputs a high-level signal to turn on the first switch unit in the target balancing module corresponding to the target cell, and the discharge unit continues to discharge and generate heat.

[0106] Step 504: The main control unit obtains N balanced temperature values of the N battery cells;

[0107] Step 505: The main control unit determines whether the balanced temperature value of the target balancing module is greater than the temperature threshold;

[0108] Step 506: When the balancing temperature value of the target balancing module is greater than or equal to the temperature threshold, the main control unit drives the front-end analog control unit to cut off the first switch unit in the target balancing module;

[0109] Step 507 , continuously monitoring whether the balancing temperature value of the target balancing module is less than the temperature threshold;

[0110] Step 508: When it is detected that the equilibrium temperature value is not less than the temperature threshold, it is determined that the software function of the front-end analog control unit is invalid, and the front-end analog control unit is controlled to be powered off;

[0111] Step 509 , when the balancing temperature value of the target balancing module is less than the temperature threshold, controlling the target balancing module to continue operating until the voltage of the target cell meets the passive balancing shutdown condition;

[0112] In step 510 , when the voltage of the target cell meets the passive balancing shutdown condition, the main control unit controls the target balancing module to stop operating through the front-end analog control unit.

[0113] According to one embodiment of the present application, Figure 6 FIG. 1 shows one of the structural block diagrams of a passive balancing device provided in some embodiments of the present application. Figure 6 As shown, a passive balancing device 600 is proposed, which is applied to the passive balancing circuit in any of the above embodiments. The passive balancing device 600 includes:

[0114] The control module 602 is configured to control the operation of a target balancing module in the N passive balancing modules according to the voltage values of the N battery cells when the voltage values of the N battery cells are obtained, and the voltage value of the target battery cell corresponding to the target balancing module satisfies the passive balancing start condition;

[0115] An acquisition module 604 is configured to acquire a balanced temperature value of the target balancing module when the target balancing module is in operation;

[0116] The control module 602 is further configured to control the operating state of the target balancing module according to the balancing temperature value of the target balancing module.

[0117] In an embodiment of the present application, a passive balancing module is provided for each battery cell in the battery module, and each passive balancing module can perform passive balanced discharge on the corresponding battery cell, and a temperature sampling module is provided at a position corresponding to each passive balancing module, that is, the balanced temperature values of N passive balancing modules are collected respectively by N temperature sampling modules, so that the control module can monitor the balanced temperature value of each passive balancing module, thereby avoiding the situation where the passive balancing module temperature is too high and the circuit board is burned due to inaccurate balanced temperature detection, and solving the problem of low temperature control accuracy in the passive balancing process due to inaccurate temperature sampling.

[0118] According to one embodiment of the present application, Figure 7 FIG2 shows a second structural block diagram of a passive balancing device provided in some embodiments of the present application. Figure 7 As shown, passive balancing device 700 includes a processor 702 and a memory 704. Memory 704 stores a program or instruction that, when executed by processor 702, implements the steps of the passive balancing method described in any of the aforementioned embodiments. Therefore, passive balancing device 700 possesses all the beneficial effects of the passive balancing method described in any of the aforementioned embodiments, and further description thereof will not be given here.

[0119] According to one embodiment of the present application, optionally, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the passive balancing method in any of the above embodiments are implemented, thereby having all the beneficial technical effects of the passive balancing method in any of the above embodiments.

[0120] The readable storage medium includes a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0121] A computer-readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. A computer-readable storage medium can be, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes: a portable computer floppy disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory card, a floppy disk, an encoding mechanical device (such as a punched card or a groove with a raised structure on which instructions are recorded), and any suitable combination of the foregoing. As used herein, a computer-readable storage medium should not be understood as a transmission signal per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium, or electrical signals transmitted through wires.

[0122] According to one embodiment of the present application, Figure 8 A structural block diagram of an energy storage system is shown in some embodiments of the present application. Figure 8 As shown, the energy storage system 800 includes: a battery module 10, the battery module 10 includes a plurality of battery cells 11, and a battery management system 802, the battery management system 802 includes the passive balancing circuit 100 in any of the above embodiments, and passively balances the charge of the plurality of battery cells in the battery module 10 based on the passive balancing circuit; and / or executes the passive balancing method in any of the above embodiments, thereby having the passive balancing circuit 100 in any of the above embodiments; and / or all the beneficial technical effects of the passive balancing method in any of the above embodiments, which will not be repeated here.

[0123] It should be clarified that in the claims, specification and drawings of this application, the term "plurality" refers to two or more. Unless otherwise clearly defined, the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the purpose of more conveniently describing this application and making the description process simpler, and is not intended to indicate or imply that the device or element referred to must have the specific orientation described, be constructed and operated in a specific orientation. Therefore, these descriptions cannot be understood as limitations on this application. The terms "connect", "install", "fix" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection between multiple objects, or a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects, or an indirect connection between multiple objects through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood based on the specific circumstances of the above data.

[0124] In the claims, specification, and drawings of this application, the terms "one embodiment," "some embodiments," "a specific embodiment," and the like mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of this application. In the claims, specification, and drawings of this application, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0125] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A passive equalization circuit, characterized in that: Applied to an energy storage system, the energy storage system includes a battery module, the battery module includes N battery cells, N is an integer greater than 1, and the passive balancing circuit includes: N passive balancing modules are connected to the N battery cells, and the N passive balancing modules correspond one to one to the N battery cells; N temperature sampling modules, each of the N temperature sampling modules being placed adjacent to a corresponding passive balancing module in the N passive balancing modules, and the N temperature sampling modules corresponding one-to-one to the N passive balancing modules, wherein the N temperature sampling modules are used to collect N balanced temperature values of the N passive balancing modules; A logic gating module, wherein an input end of the logic gating module is connected to the output ends of the N temperature sampling modules; A control module is connected to the control ends of the N passive balancing modules and the output end of the logic selection module, and is used to control the operating state of the corresponding passive balancing module according to the voltage values of the N battery cells and the N balanced temperature values.

2. The passive equalization circuit according to claim 1, characterized in that: The passive balancing module includes: a discharge unit connected to the battery cell; A first switch unit is provided between the discharge unit and the battery cell, and is used to switch the on / off state between the discharge unit and the first switch unit; The first switch unit is connected to the control module, and the control module is used to control the on-off state of the first switch unit to control the operating state of the passive balancing module.

3. The passive equalization circuit according to claim 2, characterized in that: The discharge unit in each of the passive balancing modules and the corresponding temperature sampling module are arranged adjacent to each other on the circuit board.

4. The passive equalization circuit according to any one of claims 1 to 3, characterized in that: The number of the logic gating modules is M, and the P input ends of the M logic gating modules are connected to the output ends of the N temperature sampling modules. M is an integer greater than 1, and M≤N, M×P≥N.

5. The passive equalization circuit according to any one of claims 1 to 3, characterized in that: The control module includes: A front-end analog control unit, wherein a sampling terminal of the front-end analog control unit is connected to the N battery cells, the front-end analog control unit is used to collect voltage values of the N battery cells, and an output terminal of the front-end analog control unit is connected to the control terminal of the passive balancing module; A main control unit, wherein the input end of the main control unit is connected to the output end of the front-end analog control unit and the output ends of the N temperature sampling modules, and the output end of the main control unit is connected to the input end of the front-end analog control unit; Among them, the main control unit is used to transmit a first control signal to the front-end analog control unit according to the voltage values of the N battery cells and the N balanced temperature values, so that the front-end analog control unit controls the operating state of the passive balancing module in response to the first control signal.

6. The passive equalization circuit according to claim 5, characterized in that: The control module further includes: A second switch unit is connected to the output ends of the N battery cells, and the on-off state of the second switch unit is used to control the on-off state of the output paths of the N battery cells; a third switch unit, connected between the control terminal and the ground terminal of the second switch unit; a trigger unit, wherein an output end of the trigger unit is connected to the control end of the second switch unit, and an input end of the trigger unit is connected to the output end of the main control unit; The main control unit is configured to transmit a second control signal to the second switch unit through the trigger unit to control the on / off state of the second switch unit.

7. The passive equalization circuit according to claim 6, characterized in that: The control module further includes: A constant voltage source unit, the input end of the constant voltage source unit is connected to the second switch unit, the output end of the constant voltage source unit is connected to the input end of the front-end analog control unit, and the constant voltage source unit is used to transmit a power supply signal to the front-end analog control unit.

8. A passive balancing method, characterized in that: The passive balancing circuit according to any one of claims 1 to 7, wherein the passive balancing method comprises: When the voltage values of N battery cells are obtained, the target balancing module in the N passive balancing modules is controlled to operate according to the voltage values of the N battery cells, and the voltage value of the target battery cell corresponding to the target balancing module meets the passive balancing start condition; When the target balancing module is running, obtaining a balancing temperature value of the target balancing module; The operating state of the target balancing module is controlled according to the balancing temperature value of the target balancing module.

9. The passive balancing method according to claim 8, characterized in that: The controlling the operating state of the target balancing module according to the balancing temperature value of the target balancing module includes: When the balancing temperature value of the target balancing module is greater than or equal to the temperature threshold, controlling the target balancing module to stop operating; When the balancing temperature value of the target balancing module is less than the temperature threshold, the target balancing module is controlled to keep running until the voltage value of the target battery cell meets the passive balancing shutdown condition.

10. The passive balancing method according to claim 9, characterized in that: The control module includes: a front-end analog control unit; After controlling the target balancing module to stop running when the balancing temperature value of the target balancing module is greater than or equal to the temperature threshold, the passive balancing method further includes: When the target balancing module stops running for a preset time and the balancing temperature value of the target balancing module is less than the temperature threshold, controlling the target balancing module to be in a running state until the voltage value of the target battery cell meets the passive balancing shutdown condition; When the target balancing module stops running for a preset time period and the balancing temperature value of the target balancing module is greater than or equal to the temperature threshold, power supply to the front-end analog control unit is stopped.

11. The passive balancing method according to any one of claims 8 to 10, characterized in that: The passive balancing start conditions include: The voltage value of the target battery cell is greater than the voltage values of the remaining battery cells, and a voltage difference between the voltage value of the target battery cell and the voltage values of the remaining battery cells is greater than a difference threshold, wherein the remaining battery cells are the battery cells other than the target battery cell among the N battery cells.

12. An energy storage system, characterized in that: include: A battery module, including multiple battery cells; A battery management system, comprising the passive balancing circuit according to any one of claims 1 to 7, and passively balancing the charge of the plurality of battery cells in the battery module based on the passive balancing circuit; and / or performing the passive balancing method according to any one of claims 8 to 11.

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