Battery management circuit, battery management system and electric vehicle

Abstract

The application provides a battery management circuit, a battery management system and an electric vehicle, and relates to the technical field of batteries. The battery management circuit comprises a discharge module and a cell voltage acquisition module which are separately arranged, the cell voltage acquisition module is connected with at least one pole of each cell through the discharge module, the cell voltage acquisition module is used for acquiring the cell voltage of each cell, and the discharge module is connected with the positive pole and the negative pole of a target cell in the case that the cell voltage of the target cell exceeds a target voltage, the target voltage being the voltage of other cells in the battery pack; the discharge module is used for consuming the electric energy of the target cell in the case that the discharge module is connected with the positive pole and the negative pole of the target cell. According to the application, the discharge module is arranged outside the cell voltage acquisition module, the heat dissipation area of the discharge module is increased, the output current of the cell to the discharge module is increased, the discharge efficiency of the cell is improved, and the equalization efficiency of the cell voltage is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a battery management circuit, a battery management system, and an electric vehicle. Background Technology

[0002] With the development of power batteries, the number of cells connected in series in a single battery pack is gradually increasing to give the battery pack a stronger power supply capacity, thereby adapting to the ever-increasing power supply demands. The safe use of a battery pack requires ensuring that the voltage of all cells is consistent. Therefore, to guarantee the safety of battery pack operation, ensuring the consistency of the voltage of all cells throughout the battery pack's lifespan is particularly important.

[0003] Currently, a passive equalization discharge scheme is typically used to ensure cell voltage consistency. In this scheme, the cell voltage acquisition module of the battery pack includes an equalization circuit for each cell. Each equalization circuit includes an equalization resistor connected in series with the individual cell and an equalization switch. When the cell voltage acquisition module detects that the voltage of a target cell is too high, it activates the equalization switch in the equalization circuit corresponding to that target cell. This connects the positive and negative terminals of the target cell to the equalization resistor, forming a current loop and allowing the target cell to discharge.

[0004] However, the cell voltage acquisition module is typically mounted on a separate printed circuit board (PCB) inside the battery pack. Therefore, due to the limited mounting location of the cell voltage acquisition module within the battery pack, the PCB size is usually small. This results in the equalization resistors for each cell being relatively concentrated, leading to a smaller effective heat dissipation area for the equalization resistors. Furthermore, to prevent the heat dissipation of the equalization resistors from affecting the normal operation of other components on the PCB, the current through the equalization resistors is usually limited to control the temperature rise of the equalization resistors within a certain range, thereby reducing the impact of heat dissipation. However, limiting the current through the equalization resistors results in lower discharge efficiency and poorer equalization efficiency in the equalization circuit. Summary of the Invention

[0005] To overcome the problems existing in related technologies, this application provides a battery management circuit, a battery management system, and an electric vehicle.

[0006] According to a first aspect of the embodiments of this application, a battery management circuit is provided, comprising:

[0007] The discharge module and the cell voltage acquisition module are separately configured. The cell voltage acquisition module is connected to the positive and negative terminals of each cell in the battery pack through the discharge module; or, the cell voltage acquisition module is connected to one terminal of each cell, and the other terminal of each cell is connected to the cell voltage acquisition module through the discharge module.

[0008] The cell voltage sampling module is used to collect the cell voltage of each cell, and when the cell voltage of the target cell exceeds the target voltage, it controls the connection between the discharge module and the positive and negative terminals of the target cell. The target voltage is the voltage of other cells in the battery pack, and the target cell is any cell in the battery pack.

[0009] The discharge module is used to consume the electrical energy of the target battery cell when it is connected to the positive and negative terminals of the target battery cell.

[0010] Optionally, the cell voltage acquisition module includes: an acquisition controller and multiple sampling ports, the multiple sampling ports being connected to the positive terminal of each cell and the negative terminal of the end cell, the end cell being a single battery cell directly connected to the negative terminal port of the battery pack;

[0011] Each of the sampling ports is connected to the first port of the acquisition controller via a voltage sampling resistor. The acquisition controller is used to acquire the positive and negative voltages of each cell based on the resistance value of the voltage sampling resistor, and to calculate the cell voltage of each cell based on the positive and negative voltages of each cell.

[0012] Each of the sampling ports is also directly connected to a second port of the acquisition controller, which is used to control the connection between the first target port and the second target port when the cell voltage of the target cell exceeds the target voltage. The first target port is the second port connected to the positive terminal of the target cell, and the second target port is the second port connected to the negative terminal of the target cell.

[0013] Optionally, the acquisition controller includes multiple switching components, each corresponding to one of the battery cells;

[0014] Each of the switching devices is connected to two second ports that are respectively connected to the two poles of the corresponding battery cell. The switching device is used to connect the two connected second ports when the battery cell voltage of the corresponding battery cell exceeds the target voltage, and to disconnect the two connected second ports when the battery cell voltage of the corresponding battery cell does not exceed the target voltage.

[0015] Optionally, the acquisition controller includes: a control module;

[0016] The control module is connected to the first port and each of the switching devices. The control module is used to collect the positive and negative voltages of each cell, calculate the cell voltage of each cell, and output an on control signal to the target switching device corresponding to the target cell when the cell voltage of the target cell exceeds the target voltage, and output an off control signal to the target switching device when the cell voltage of the target cell does not exceed the target voltage.

[0017] The switch is used to connect the two second ports under the control of the open control signal, and to disconnect the two second ports under the control of the close control signal.

[0018] Optionally, the discharge module includes: a plurality of discharge components; the plurality of discharge components are connected to the cell voltage acquisition module and are respectively connected to at least one of the positive and negative terminals of each cell.

[0019] Optionally, the battery management circuit includes: a flexible circuit board (FPC) with multiple voltage sampling lines disposed on the FPC;

[0020] The plurality of voltage sampling lines are all connected to the cell voltage acquisition module and are respectively connected to the positive and negative terminals of each cell. The voltage sampling line connected to at least one terminal of each cell is the discharge component, and the impedance value of the voltage sampling line of the discharge component is at least equal to the equalization resistance value. The equalization resistance value is determined based on the maximum operating voltage and the maximum equalization current of the cell. The maximum equalization current is a preset maximum value of the current flowing through the voltage sampling line.

[0021] Optionally, the cell voltage acquisition module is integrated on the FPC.

[0022] Optionally, the discharge component includes a discrete resistor.

[0023] Optionally, each of the discharge components is connected to the positive terminal of a different cell or the negative terminal of the end cell.

[0024] According to a second aspect of the embodiments of this application, a battery management system is provided, including: a battery pack and a battery management circuit connected to the battery pack, wherein the battery management circuit is any of the circuits described in the first aspect.

[0025] According to a third aspect of the embodiments of this application, an electric vehicle is provided, including: the battery management system described in the second aspect.

[0026] The technical solutions provided by the embodiments of this application have at least the following beneficial effects:

[0027] The battery management circuit includes a separately configured discharge module and a cell voltage acquisition module. The cell voltage acquisition module is connected to the positive and negative terminals of each cell in the battery pack through the discharge module; alternatively, the cell voltage acquisition module is connected to one terminal of each cell, and the other terminal of each cell is connected to the cell voltage acquisition module through the discharge module. In this technical solution, the cell voltage acquisition module is used to acquire the cell voltage of each cell. When the cell voltage of a target cell exceeds the target voltage of other cells, indicating that the target cell's cell voltage is relatively high, the module controls the connection between the discharge module and the positive and negative terminals of the target cell to form a current loop between the cell and the discharge module. This allows the discharge module to consume the target cell's energy, achieving discharge of the target cell and reducing its cell voltage. By correcting the cells with excessively high voltages in the battery pack, the consistency of cell voltages in the battery pack is maintained to a certain extent.

[0028] Furthermore, in this application's technical solution, by externalizing the discharge module to the cell voltage acquisition module, not only can the size of the cell voltage acquisition module be reduced, but the heat generated by the discharge module during energy consumption can also be prevented from affecting the cell voltage acquisition module. This increases the output current from the cell to the discharge module, allowing the discharge module to accelerate the energy consumption efficiency of the cell, improve the cell's discharge efficiency, accelerate the voltage drop rate, and improve the cell's voltage balancing efficiency. In addition, externalizing the discharge module also frees its size from the constraints of the cell voltage acquisition module. This allows for an increase in the size of the discharge module, increasing its heat dissipation area, further increasing the cell's output current to the discharge module, improving the cell's discharge efficiency, and enhancing the cell's voltage balancing efficiency.

[0029] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application, and do not constitute an undue limitation of this application.

[0031] Figure 1 This is one of the structural schematic diagrams of the battery management system provided in the embodiments of this application;

[0032] Figure 2 This is a second schematic diagram of the battery management system provided in the embodiments of this application;

[0033] Figure 3 This is the third schematic diagram of the battery management system provided in the embodiments of this application;

[0034] Figure 4 This is the fourth schematic diagram of the battery management system provided in the embodiments of this application;

[0035] Figure 5 This is the fifth schematic diagram of the battery management system provided in the embodiments of this application;

[0036] Figure 6 This is the sixth schematic diagram of the battery management system provided in the embodiments of this application;

[0037] Figure 7 This is the seventh schematic diagram of the battery management system provided in the embodiments of this application;

[0038] Figure 8 This is the eighth schematic diagram of the battery management system provided in the embodiments of this application.

[0039] Figure 9 This is the ninth schematic diagram of the battery management system provided in the embodiments of this application;

[0040] Figure 10 This is the tenth schematic diagram of the battery management system provided in the embodiments of this application;

[0041] Figure 11 This is the eleventh schematic diagram of the battery management system provided in the embodiments of this application. Detailed Implementation

[0042] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0043] Please refer to Figure 1 This illustrates a schematic diagram of a battery management circuit provided in an embodiment of this application. Figure 1 As shown, the battery management circuit 1 includes a separately configured discharge module 11 and a cell voltage acquisition module 12. The cell voltage acquisition module 12 is connected to the positive and negative terminals of each cell 21 in the battery pack 2.

[0044] In this embodiment, the cell voltage acquisition module 12 is connected to at least one pole of each cell 21 via the discharge module 11. In some embodiments, the cell voltage acquisition module 12 can be connected to the positive pole of each cell 21 via the discharge module 11. Alternatively, the cell voltage acquisition module 12 can be connected to the negative pole of each cell 21 via the discharge module 11. Alternatively, the cell voltage acquisition module 12 can be connected to both the positive and negative poles of each cell 21 via the discharge module 11. Alternatively, the cell voltage acquisition module 12 can be connected to the positive pole of every other cell 21 via the discharge module 11. Alternatively, the cell voltage acquisition module 12 can be connected to the negative pole of every other cell 21 via the discharge module 11.

[0045] The cell voltage sampling module 12 is used to collect the cell voltage of each cell 21, and when the cell voltage of the target cell exceeds the target voltage, it controls the connection of the discharge module 11 to the positive and negative terminals of the target cell. The discharge module 11 is used to consume the electrical energy of the target cell when connected to its positive and negative terminals. The target cell is any cell in the battery pack 2. The target voltage is the voltage of all other cells in the battery pack 2 except the target cell.

[0046] In this embodiment, the cell voltage sampling module 12 can be used to collect the cell voltage of each cell 21 and determine the relationship between the cell voltage of each cell 21 and the target voltage. Furthermore, if the cell voltage does not exceed the target voltage, it indicates that the cell voltage of cell 21 is not higher than the cell voltages of other cells in the battery pack besides the target cell. The cell voltage sampling module 12 can control the disconnection of the positive and negative terminals of the discharge module 11 and cell 21 to prevent the cell 21 from forming a current loop with the discharge module 11. The discharge module 11 will not consume the energy of cell 21. If the cell voltage exceeds the target voltage, it indicates that the cell voltage of cell 21 is higher than the cell voltages of other cells in the battery pack besides the target cell. The cell voltage sampling module 12 can control the connection of the positive and negative terminals of the discharge module 11 and cell 21 to prevent the cell 21 from forming a current loop with the discharge module 11. The discharge module 11 is used to consume the electrical energy of the battery cell 21, causing the battery cell 21 to discharge in the current loop, thereby reducing the battery cell voltage of the battery cell 21. By continuously consuming the electrical energy of the battery cell 21 in the closed loop formed by the discharge module 11 and the battery cell 21, the battery cell 21 continues to discharge in the current loop until the battery cell voltage of the battery cell 21 is reduced to the target voltage, correcting the cells with excessively high voltage in the battery pack and maintaining the consistency of the battery cell voltage to a certain extent.

[0047] It should be noted that the battery pack 2 includes multiple cells connected in series. All figures in the embodiments of this application are illustrated by the example that the battery pack 2 includes cells m, m-1, ..., n+1, battery n, n-1, ..., cell 2 and cell 1, for a total of m cells 21.

[0048] In summary, the battery management circuit provided in this application includes a discharge module and a cell voltage acquisition module. The cell voltage acquisition module is connected to the positive and negative terminals of each cell in the battery pack, wherein the cell voltage acquisition module is connected to at least one terminal of each cell through the discharge module. In this technical solution, the cell voltage sampling module is used to acquire the cell voltage of each cell, and when the cell voltage of a target cell exceeds the target voltage of other cells, indicating that the cell voltage of the target cell is higher than that of other cells, the discharge module is controlled to connect to the positive and negative terminals of the target cell, so that the cell and the discharge module form a current loop, thereby allowing the discharge module to consume the electrical energy of the target cell, realizing the discharge of the target cell, and achieving the purpose of reducing the cell voltage of the target cell. By correcting the cells with higher cell voltages in the battery pack, the consistency of cell voltages in the battery pack is maintained to a certain extent.

[0049] Furthermore, in this application's technical solution, by externalizing the discharge module to the cell voltage acquisition module, not only can the size of the cell voltage acquisition module be reduced, but the heat generated by the discharge module during energy consumption can also be prevented from affecting the cell voltage acquisition module. This increases the output current from the cell to the discharge module, allowing the discharge module to accelerate the energy consumption efficiency of the cell, improve the cell's discharge efficiency, accelerate the voltage drop rate, and improve the cell's voltage balancing efficiency. In addition, externalizing the discharge module also frees its size from the constraints of the cell voltage acquisition module. This allows for an increase in the size of the discharge module, increasing its heat dissipation area, further increasing the cell's output current to the discharge module, improving the cell's discharge efficiency, and enhancing the cell's voltage balancing efficiency.

[0050] Optionally, such as Figure 2 As shown, the cell voltage acquisition module 12 includes an acquisition controller 121 and multiple sampling ports P0. The multiple sampling ports P0 are respectively connected to the positive terminal and the negative terminal of each cell 21. The final cell is a single battery cell directly connected to the negative terminal of the battery pack 2. Correspondingly, at least some of the sampling ports P0 are connected to at least one of the positive and negative terminals of each cell 21 through the discharge module 11.

[0051] Each sampling port P0 is connected to the first port P1 of the acquisition controller 121 through a voltage sampling resistor Rc. The acquisition controller 121 is used to acquire the positive and negative voltages of each cell 21 according to the resistance value of the voltage sampling resistor Rc, and to calculate the cell voltage of each cell 21 based on the positive and negative voltages of each cell 21.

[0052] Each sampling port P0 is also directly connected to the second port P2 of the acquisition controller 121. The acquisition controller 121 is used to control the connection between the first target port and the second target port when the cell voltage of the target cell 21 exceeds the target voltage. The first target port is the second port connected to the positive terminal of the target cell 21. The second target port is the second port connected to the negative terminal of the target cell 21.

[0053] It should be noted that, Figure 2 Taking the example where each sampling port P0 is connected to the battery cell 21 via the discharge module 11, and... Figure 2 The connection relationship between the cell voltage acquisition module 12 and cell n 21 in the battery pack 2 is illustrated as an example, showing the connection relationship between the cell voltage acquisition module 12 and each cell 21 in the battery pack 2. Figure 2 In the circuit structure shown, when the cell voltage of the target cell 21 exceeds the target voltage, the acquisition controller 121 controls the connection of the first target port and the second target port, so that the target cell 21 and the discharge module 11 form a current loop. The output current of the positive terminal of the target cell 21 flows to the negative terminal of the target cell 21 after passing through the discharge module 11, the acquisition controller 121, and the discharge module 11. The discharge module 11 consumes the electrical energy of the target cell 21 in this current loop, realizing the discharge of the target cell 21 and achieving the purpose of reducing the cell voltage of the target cell 21.

[0054] Optionally, for each battery cell 21, the acquisition controller 121 is connected to the positive (negative) terminal of the battery cell 21 through the sampling port P0 to acquire the current at the positive (negative) terminal of the battery cell 21, and then, based on the current and voltage sampling resistor Rc and the impedance R of the connection line between the sampling port P0 and the positive (negative) terminal of the battery cell 21, the controller acquires the current at the positive (negative) terminal of the battery cell 21. L The impedance value is used to calculate the positive voltage (negative voltage) of cell 21. Then, the acquisition controller 121 is used to calculate the difference between the positive voltage and the negative voltage of cell 21 to obtain the cell voltage of cell 21.

[0055] Specifically, with Figure 2Taking cell n as an example, the data acquisition controller 121 acquires the current I+ at the positive terminal of cell 21 and calculates the positive terminal voltage V+ of cell 21 according to the first formula. It also acquires the current I- at the negative terminal of cell 21 and calculates the negative terminal voltage V- of cell 21 according to the second formula. Furthermore, it calculates the difference between the positive terminal voltage V+ and the negative terminal voltage V- of cell 21 to obtain the cell voltage V+-V-. The first formula satisfies: V+=I+ / (Rc+R L1 In the first formula, Rc represents the resistance value of the voltage sampling resistor Rc; R L1 The impedance R represents the connection line between sampling port P0 and the positive terminal of cell 21. L The impedance value. The second formula satisfies: V-=I+ / (Rc+R L2 In the second formula, Rc represents the resistance value of the voltage sampling resistor Rc; R L2 The impedance R represents the connection line between sampling port P0 and the negative terminal of cell 21. L The impedance value.

[0056] Optionally, the acquisition controller 121 is used to determine the relationship between the cell voltage of each cell 21 and the target voltage. Furthermore, if the cell voltage of the target cell 21 exceeds the target voltage, indicating that the cell voltage of the target cell is higher than the cell voltages of other cells, the controller connects the first target port and the second target port to form a current loop between the target cell 21 and the discharge module 11. This allows the discharge module 11 to consume the energy of the target cell 21, discharging it and reducing its cell voltage. If the cell voltage of the target cell 21 does not exceed the target voltage, indicating that the cell voltage of the target cell 21 is not higher than the cell voltages of other cells in the battery pack, the controller disconnects the first target port and the second target port to prevent a current loop from forming between the target cell 21 and the discharge module 11, thus preventing the discharge module 11 from consuming the energy of the target cell 21.

[0057] In some embodiments of this application, such as Figure 3 As shown, the data acquisition controller 121 includes multiple switching components S. Each switching component S corresponds one-to-one with a battery cell 21 in the battery pack 2.

[0058] Each switch S is connected to two second ports P2, which are respectively connected to the two poles of the corresponding cell 21. The switch S is used to connect the two connected second ports P2 when the cell voltage of the corresponding cell 21 exceeds the target voltage, and to disconnect the two connected second ports P2 when the cell voltage of the corresponding cell 21 does not exceed the target voltage.

[0059] It should be noted that, Figure 3Taking the example where each sampling port P0 is connected to the battery cell 21 via the discharge module 11, and... Figure 3 The connection relationship between the cell voltage acquisition module 12 and cell n 21 in the battery pack 2 is illustrated as an example, showing the connection relationship between the cell voltage acquisition module 12 and each cell 21 in the battery pack 2. Figure 3 In the circuit structure shown, when the cell voltage of the corresponding cell 21 exceeds the target voltage, the switch S controls the two second ports P2 connected to the switch S to form a current loop between the cell 21 corresponding to the switch S and the discharge module 11. The output current from the positive terminal of the cell 21 flows to the negative terminal of the cell 21 after passing through the discharge module 11, the switch S, and the discharge module 11. The discharge module 11 consumes the electrical energy of the target cell 21 in this current loop, realizing the discharge of the cell 21 and achieving the purpose of reducing the cell voltage of the cell 21.

[0060] In an optional configuration, the switch S can be used to acquire the cell voltage of its corresponding cell 21. Then, the relationship between the cell voltage of the corresponding cell 21 and the target voltage can be determined. If the cell voltage exceeds the target voltage, the two connected second ports P2 are connected to form a current loop between the corresponding cell 21 and the discharge module 11, thus discharging the corresponding cell 21. If the cell voltage does not exceed the target voltage, the two connected second ports P2 are disconnected to prevent the corresponding cell 21 from forming a current loop with the discharge module 11, thus preventing the corresponding cell 21 from discharging.

[0061] In another alternative embodiment, the acquisition controller 121 includes a control module. The control module is connected to the first port P1 and each switch S.

[0062] The control module is used to collect the positive and negative voltages of each battery cell 21, calculate the cell voltage of each battery cell 21, and output an on control signal to the target switch S corresponding to the target battery cell 21 when the cell voltage of the target battery cell 21 exceeds the target voltage, and output an off control signal to the target switch S when the cell voltage of the target battery cell 21 does not exceed the target voltage. The method by which the control module calculates the cell voltage can refer to the aforementioned cell voltage calculation method, and will not be elaborated here.

[0063] The switch S is used to connect the two connected second ports P2 under the control of the turn-on control signal and disconnect the two connected second ports P2 under the control of the turn-off control signal. For example, the switch S can be a transistor or a relay, etc. For instance, the switch S can be a PMOS transistor, where the turn-on control signal is a low-level signal and the turn-off control signal is a high-level signal. The gate of the PMOS transistor is connected to the control module, the source is connected to the second port P2 connected to the positive terminal of the corresponding cell 21, and the drain is connected to the second port P2 connected to the negative terminal of the corresponding cell 21. The control module is used to output a low-level signal to the target switch S corresponding to the target cell 21 when the cell voltage of the target cell 21 exceeds the target voltage, so as to turn on the target switch S and connect the two connected second ports P2. The control module is also used to output a high-level signal to the target switch S when the cell voltage of the target cell 21 does not exceed the target voltage, so as to turn off the target switch S and disconnect the two connected second ports P2.

[0064] In some embodiments of this application, such as Figure 4 As shown, the discharge module 11 includes a plurality of discharge components 111. The plurality of discharge components 111 are connected to the cell voltage acquisition module 12, and are respectively connected to at least one of the positive and negative terminals of each cell 21.

[0065] In some embodiments, the battery pack 2 includes m cells 21. The discharge module 11 may include m discharge components 111. Each discharge component 111 is connected to the positive terminal of a different cell 21, so that the cell voltage acquisition module 12 is connected to the positive terminal of each cell 21 through the discharge module 11. Alternatively, each discharge component 111 is connected to the negative terminal of a different cell 21, so that the cell voltage acquisition module 12 is connected to the negative terminal of each cell 21 through the discharge module 11. Alternatively, the discharge module 11 includes m+1 discharge components 111. Each discharge component 111 is connected to the positive terminal of a different cell 21, or to the negative terminal of the end cell 21. Based on this, the cell voltage acquisition module 12 can be connected to both the positive and negative terminals of each cell 21 through the discharge module 11.

[0066] Alternatively, the discharge module 11 includes: Each discharge component 111 is connected to the positive terminal of a cell 21 spaced apart by one cell 21, so that the cell voltage acquisition module 12 is connected to the positive terminal of each cell 21 spaced apart through the discharge module 11. Alternatively, each discharge component 111 is connected to the negative terminal of a cell 21 spaced apart by one cell 21, so that the cell voltage acquisition module 12 is connected to the negative terminal of each cell 21 spaced apart through the discharge module 11. It should be noted that... Figure 4Taking the cell voltage acquisition module 12 as an example, it can be connected to the positive and negative terminals of each cell 21 through the discharge component 111. Figure 4 The connection relationship between the cell voltage acquisition module 12 and the cell n21 in the battery pack 2 is illustrated as an example, showing the connection relationship between the cell voltage acquisition module 12 and each cell 21 in the battery pack 2.

[0067] It should be noted that since the multiple cells 21 in the battery pack 2 are connected in series, for two adjacent cells 21, the discharge assembly 111 is connected to the negative terminal of one cell 21, which is also connected to the positive terminal of the other cell 21. Similarly, the discharge assembly 111 is connected to the positive terminal of one cell 21, which is also connected to the negative terminal of the other cell 21.

[0068] In an alternative embodiment, a single discharge component 111 may include at least one discrete resistor. If the discharge component 111 includes multiple discrete resistors, these resistors are connected in series. In one embodiment, the total resistance of the discrete resistors in a single discharge component 111 must be at least equal to the equalization resistance. The equalization resistance is determined based on the cell's maximum operating voltage and the maximum equalization current. The maximum equalization current is the maximum value of the current flowing through the preset voltage sampling line. The maximum equalization current can be determined based on the equalization current requirement and the temperature at which the equalization temperature rises.

[0069] In some embodiments, such as Figure 5 As shown, the battery management circuit 1 also includes a flexible printed circuit (FPC) 13. Multiple voltage sampling lines are provided on the FPC 13. These voltage sampling lines are all connected to the cell voltage acquisition module 12, and are respectively connected to the positive and negative terminals of each cell 21. That is, the cell voltage acquisition module 12 is connected to the positive and negative terminals of each cell 21 through the multiple voltage sampling lines on the FPC. Based on this, the discrete resistor Rb in the discharge module 11 can also be placed on the FPC 13.

[0070] Since the wiring area of ​​the FPC is larger than that of the cell voltage acquisition module 12, the discrete resistors Rb in the discharge module 11 on the FPC are also relatively dispersed. This effectively increases the size of the discharge module 11, thereby increasing its heat dissipation area. This further increases the output current of the cell 21 to the discharge module 11, improves the discharge efficiency of the cell 21, and enhances the cell voltage balancing efficiency.

[0071] Furthermore, by externalizing the discharge module 11 into the cell voltage acquisition module 12, the size of the cell voltage acquisition module 12 can be effectively reduced. Tests have shown that the area of ​​the cell voltage acquisition module 12 can be reduced by more than 50%. Therefore, the cell voltage acquisition module 12 can be integrated onto the FPC 13 to further reduce the area of ​​the battery management circuit 1.

[0072] For example, such as Figure 6 As shown, taking a single discharge component 111 as an example with a discrete resistor Rb, the battery pack 2 includes m cells 21, and correspondingly, the FPC 13 is provided with m+1 voltage sampling lines; the discharge module 11 includes m+1 discrete resistors Rb; the cell voltage acquisition module 12 includes an acquisition controller 121 and m+1 sampling ports P0. The acquisition controller 121 can be an analog front end (AFE) module, which includes m switches S.

[0073] Each discrete resistor Rb is connected to the cell voltage acquisition module 12 via a voltage acquisition line, and is also connected to the positive terminal of a different cell 21 or the negative terminal of the end cell 21 via the same voltage acquisition line. In the cell voltage acquisition module 12, each sampling port P0 is connected to the positive terminal of a cell 21 via a different discrete resistor Rb; or, it is connected to the negative terminal of the end cell 21 via a different discrete resistor Rb. Furthermore, each sampling port P0 is also connected to the first port P1 of the acquisition controller 121 via a voltage sampling resistor Rc, and each sampling port P0 is also directly connected to the second port P2 of the acquisition controller 121. In the acquisition controller 121, each switch S is connected to the two second ports P2 corresponding to the two poles of the cell 21.

[0074] Taking the connection between the cell voltage acquisition module 12 and cell n 21 in the battery pack 2 as an example, the positive terminal of cell n 21 is connected to a sampling port P0 of the cell voltage acquisition module 12 through a discrete resistor Rb. This sampling port P0 is connected to the first port P1 of the acquisition controller 121 through a voltage sampling resistor Rc. The sampling port P0 is also directly connected to a switch S corresponding to cell n 21 in the acquisition controller 121.

[0075] The negative terminal of cell n 21 is connected to a sampling port P0 of cell voltage acquisition module 12 via a discrete resistor Rb. This sampling port P0 is connected to the first port P1 of acquisition controller 121 via a voltage sampling resistor Rc. Sampling port P0 is also directly connected to a switch S corresponding to cell n 21 in acquisition controller 121.

[0076] It should be noted that, since the switching element S typically has on-resistance when turned on, therefore, Figure 6The resistance Rs represents the on-resistance of the switch S when it is turned on. Similarly, since the voltage sampling lines on the FPC also have impedance, Figure 6 resistor R L This represents the impedance of the voltage sampling line.

[0077] The data acquisition controller 121 is used to acquire the cell voltage of each cell 21 in the battery pack 2, and for each cell 21, to determine whether the cell voltage of cell 21 exceeds the target voltage. If the cell voltage of cell n 21 does not exceed the target voltage, the data acquisition controller 121 controls the switch S corresponding to cell n 21 to close, disconnecting the discrete resistor Rb from the positive and negative terminals of cell n 21. At this time, the voltage sampling resistor Rc and resistor R connected to cell n 21 are... L The discrete resistors Rb are connected in series. The data acquisition controller 121 is used to sample the voltage based on the resistors Rc and Rb. L And the resistance value of discrete resistor Rb, calculate the voltage of the positive (negative) terminal of cell n 21, and then obtain the cell voltage of cell n 21.

[0078] If the cell voltage of cell n21 exceeds the target voltage, the acquisition controller 121 controls the switch S corresponding to cell n21 to open, connecting the discrete resistor Rb to the positive and negative terminals of cell n21 to form a current loop, so that cell n21 discharges in the current loop. At this time, the resistor Rb connected to cell n21... L The discrete resistors Rb are connected in series. The total resistance in the current loop is composed of resistor R. L It consists of discrete resistors Rb and Rs.

[0079] Thus, the output current (also known as the equalization current) I of cell n21 satisfies: I = Vn21 / ((Rb1+Rb2)+(R L1 +R L2 Vn21 represents the cell voltage of cell n21. Rb1 represents the resistance value of the discrete resistor Rb connected to the positive terminal of cell n21. Rb2 represents the resistance value of the discrete resistor Rb connected to the negative terminal of cell n21. L1 The impedance R of the voltage acquisition line connected to the positive terminal of cell n21 is represented. L The impedance value. R L2 The impedance R of the voltage acquisition line connected to the negative terminal of cell n21 is indicated. L The impedance value. Rs represents the conduction impedance of the switch S corresponding to cell n 21 when it is turned on. Figure 6 In the diagram, Rb1 represents the discrete resistor Rb connected to the positive terminal of cell n21. Rb2 represents the discrete resistor Rb connected to the negative terminal of cell n21. L1The impedance R of the voltage acquisition line connected to the positive terminal of cell n21 is represented. L R L2 The impedance R of the voltage acquisition line connected to the negative terminal of cell n21 is indicated. L .

[0080] In another alternative embodiment, the discharge component 111 can be a voltage sampling line provided on the FPC 13. This can also be understood as the discharge component 111 being located within the voltage sampling line on the FPC 13. Figure 7 As shown, the FPC 13 is equipped with multiple voltage sampling lines, which are all connected to the cell voltage acquisition module 12 and are respectively connected to the positive and negative terminals of each cell 21.

[0081] In this configuration, at least one terminal of each battery cell 21 is connected to a voltage sampling line, which serves as a discharge assembly 111. Therefore, the impedance of the voltage sampling line serving as the discharge assembly 111 can be understood as the aforementioned impedance R. L +Discrete resistor Rs. To facilitate understanding of the scheme where the voltage sampling line is the discharge component 111, Rs is used as the discrete resistor. L +Rs represents the impedance of the voltage sampling line used as the discharge component 111. In this embodiment, the impedance value of the voltage sampling line used as the discharge component 111 needs to be at least equal to the equalization resistance value. The equalization resistance value is determined based on the maximum operating voltage and maximum equalization current of the cell 21.

[0082] The maximum balancing current is the preset maximum current flowing through the voltage sampling line. The maximum balancing current can be determined based on the balancing current requirements and the temperature at which the balancing temperature rises. For example, without considering the design impedance of the voltage sampling line on the FPC, the balancing resistance is typically greater than or equal to 10Ω. However, due to FPC design requirements, the impedance of the voltage sampling line on the FPC is typically required to be less than or equal to 2Ω. Therefore, considering the design impedance of the voltage sampling line on the FPC, the balancing resistance can typically be greater than or equal to 11 (or 12)Ω.

[0083] For example, the battery pack uses ternary lithium-ion cells. Assuming the maximum operating voltage of the ternary lithium-ion cell is 4.5V and the maximum balancing current is designed to be 200mA, then the balancing resistance, i.e., the impedance R of the voltage sampling line on the FPC, is... L +Rs can be designed as: (4.5V / 200mA) / 2=11.25Ω.

[0084] It should be noted that, Figure 7 Taking the cell voltage acquisition module 12 as an example, which can be connected to the positive and negative terminals of each cell 21 via the discharge component 111, each voltage sampling line on the FPC 13 is a discharge component 111. Furthermore... Figure 7The connection relationship between the cell voltage acquisition module 12 and cell n 21 in the battery pack 2 is illustrated as an example, showing the connection relationship between the cell voltage acquisition module 12 and each cell 21 in the battery pack 2.

[0085] For example, please continue to refer to Figure 7 The battery pack 2 includes m cells 21. Correspondingly, the FPC 13 is provided with m+1 voltage sampling lines as discharge components 111. The cell voltage acquisition module 12 includes an acquisition controller 121 and m+1 sampling ports P0. The acquisition controller 121 can be an AFE module, which includes m switches S.

[0086] In the cell voltage acquisition module 12, each sampling port P0 is connected to the positive terminal of a cell 21 via a different voltage sampling line; or, it is connected to the negative terminal of the end cell 21 via a different voltage sampling line. Furthermore, each sampling port P0 is also connected to the first port P1 of the acquisition controller 121 via a voltage sampling resistor Rc, and each sampling port P0 is also directly connected to the second port P2 of the acquisition controller 121. In the acquisition controller 121, each switch S is connected to the two second ports P2 corresponding to the two poles of the cell 21.

[0087] Taking the connection between the cell voltage acquisition module 12 and cell n 21 in the battery pack 2 as an example, the positive terminal of cell n 21 is connected to a sampling port P0 of the cell voltage acquisition module 12 through a voltage sampling line. This sampling port P0 is connected to the first port P1 of the acquisition controller 121 through a voltage sampling resistor Rc. The sampling port P0 is also directly connected to a switch S corresponding to cell n 21 in the acquisition controller 121.

[0088] The negative terminal of cell n 21 is connected to a sampling port P0 of cell voltage acquisition module 12 via a voltage sampling line. This sampling port P0 is connected to the first port P1 of acquisition controller 121 via voltage sampling resistor Rc. Sampling port P0 is also directly connected to a switch S corresponding to cell n 21 in acquisition controller 121.

[0089] It should be noted that, with Figure 6 Similarly, Figure 7 In this context, resistance Rs represents the conduction impedance of switch S when it is turned on, and resistance Rs+R... L This represents the impedance of the voltage sampling line.

[0090] The data acquisition controller 121 is used to acquire the cell voltage of each cell 21 in the battery pack 2, and for each cell 21, to determine whether the cell voltage of cell 21 exceeds the target voltage. If the cell voltage of cell n 21 does not exceed the target voltage, the data acquisition controller 121 controls the switch S corresponding to cell n 21 to close. At this time, the voltage sampling resistor Rc and resistor Rs+R connected to cell n 21 are closed. L They are connected in series. The data acquisition controller 121 is used to sample the voltage from resistor Rc and resistor Rs+R. L Calculate the voltage at the positive (negative) terminal of cell n21 based on the resistance value, and then obtain the cell voltage of cell n21.

[0091] If the cell voltage of cell n21 exceeds the target voltage, the acquisition controller 121 controls the corresponding switch S of cell n21 to open, connecting the voltage sampling line with the positive and negative terminals of cell n21 to form a current loop, so that cell n21 discharges in the current loop. At this time, the total resistance in the current loop is reduced by resistance Rs + R L Together with the resistor Rs, it forms a complete structure.

[0092] In some embodiments, since the discharge components 111 are arranged in the voltage sampling lines on the FPC 13, and the voltage sampling lines on the FPC are usually distributed throughout the battery pack 2 according to the position of the cell 21 in the battery pack 2, it can be considered that the discharge components 111 corresponding to each cell 21 on the FPC 13 are also distributed throughout the battery pack 2. Therefore, the discharge module 11 has a large heat dissipation space, which effectively improves the heat dissipation efficiency of the discharge module 11. This can further increase the output current of the cell 21 to the discharge module 11, improve the discharge efficiency of the cell 21, and improve the cell voltage equalization efficiency.

[0093] To facilitate understanding of the scheme in this application where the discharge component 111 is disposed in the voltage sampling line on the FPC 13, the following example illustrates the scheme further by assuming that each voltage sampling line on the FPC 13 is a discharge component 111. Figure 8 As shown, the battery pack 2 includes multiple battery cells 21, and the multiple battery cells 21 are connected in series via connecting copper strips 22. The battery management circuit 1 includes a battery cell voltage acquisition module 12. Figure 8 (not shown in the image) and FPC 13.

[0094] The FPC 13 is equipped with multiple voltage sampling lines 131. Each voltage sampling line 131 is connected to the cell voltage acquisition module 12 and, via nickel strips 132, to the positive terminal 211 and negative terminal 212 of each cell 21 in the battery pack 2. Furthermore, each voltage sampling line 131 has an impedance R. L +Rs, Figure 8 With resistor RL +Rs represents the equivalent resistance 1311 of the voltage sampling line 131, which serves as the impedance of the discharge component 111.

[0095] As a further example, such as Figure 9 As shown, the cell voltage acquisition module 12 can be mounted on a PCB board. The acquisition controller 121 in the cell voltage acquisition module 12 can be an AFE module.

[0096] As a further example, the PCB board containing the cell voltage acquisition module 12 can be integrated onto the FPC 13. Therefore, please refer to... Figure 9 The PCB board on which the cell voltage acquisition module 12 is located can also have PCB soldering gold fingers 122. Correspondingly, such as Figure 10 As shown, the FPC 13 can have a reserved soldering area 133 for the PCB board, and the soldering area 133 has FPC soldering gold fingers 134. The area of ​​the PCB board where the cell voltage acquisition module 12 is located can be no larger than 70mm×70mm, so the area of ​​the soldering area 133 can be no larger than 70mm×70mm.

[0097] By soldering the PCB board containing the cell voltage acquisition module 12 to the FPC soldering gold fingers 134 via PCB soldering gold fingers 122, the solution of integrating the cell voltage acquisition module 12 into the FPC 13 is achieved, realizing the following: Figure 11 The cell voltage acquisition module 12 shown is connected to each cell 21 in the battery pack 2.

[0098] Taking the connection between the cell voltage acquisition module 12 and cell n 21 in the battery pack 2 as an example, the positive terminal 211 of cell n 21 is connected to a sampling port P0 of the cell voltage acquisition module 12 through the voltage sampling line 131. This sampling port P0 is connected to the first port P1 of the acquisition controller 121 through the voltage sampling resistor Rc. The sampling port P0 is also directly connected to a switch S corresponding to cell n 21 in the acquisition controller 121.

[0099] The negative terminal 212 of cell n 21 is connected to a sampling port P0 of cell voltage acquisition module 12 via voltage sampling line 131. This sampling port P0 is connected to the first port P1 of acquisition controller 121 via voltage sampling resistor Rc. Sampling port P0 is also directly connected to a switch S corresponding to cell n 21 in acquisition controller 121.

[0100] The data acquisition controller 121 is used to acquire the cell voltage of each cell 21 in the battery pack 2, and for each cell 21, to determine whether the cell voltage of cell 21 exceeds the target voltage. If the cell voltage of cell n 21 does not exceed the target voltage, the data acquisition controller 121 controls the corresponding switch S of cell n 21 to close. If the cell voltage of cell n 21 exceeds the target voltage, the data acquisition controller 121 controls the corresponding switch S of cell n 21 to open, connecting the voltage sampling line 131 with the positive and negative terminals of cell n 21 to form a current loop, so that cell n 21 discharges in the current loop, thereby reducing the cell voltage of cell 21. The discharge module 11 continuously consumes the electrical energy of the battery cell 21 in the closed circuit formed by the battery cell 21 and the discharge module 11, so that the battery cell 21 continues to discharge in the current circuit until the battery cell voltage of the battery cell 21 drops to the target voltage, correcting the battery cells with high voltage in the battery pack and maintaining the consistency of battery cell voltage in the battery pack to a certain extent.

[0101] In summary, the battery management circuit provided in this application includes a discharge module and a cell voltage acquisition module. The cell voltage acquisition module is connected to the positive and negative terminals of each cell in the battery pack, wherein the cell voltage acquisition module is connected to at least one terminal of each cell through the discharge module. In this technical solution, the cell voltage sampling module is used to acquire the cell voltage of each cell, and when the cell voltage of a target cell exceeds the target voltage of other cells, indicating that the cell voltage of the target cell is higher than that of other cells, the discharge module is controlled to connect to the positive and negative terminals of the target cell, so that the cell and the discharge module form a current loop, thereby allowing the discharge module to consume the electrical energy of the target cell, realizing the discharge of the target cell, and achieving the purpose of reducing the cell voltage of the target cell. By correcting the cells with higher cell voltages in the battery pack, the consistency of cell voltages in the battery pack is maintained to a certain extent.

[0102] Furthermore, in this application's technical solution, by externalizing the discharge module to the cell voltage acquisition module, not only can the size of the cell voltage acquisition module be reduced, but the heat generated by the discharge module during energy consumption can also be prevented from affecting the cell voltage acquisition module. This increases the output current from the cell to the discharge module, allowing the discharge module to accelerate the energy consumption efficiency of the cell, improve the cell's discharge efficiency, accelerate the voltage drop rate, and improve the cell's voltage balancing efficiency. In addition, externalizing the discharge module also frees its size from the constraints of the cell voltage acquisition module. This allows for an increase in the size of the discharge module, increasing its heat dissipation area, further increasing the cell's output current to the discharge module, improving the cell's discharge efficiency, and enhancing the cell's voltage balancing efficiency.

[0103] This application also provides a battery management system. The battery management system includes a battery pack and a battery management circuit connected to the battery pack. The battery management circuit is any of the circuits described in this application. In the battery management system provided in this application, the battery management circuit includes a discharge module and a cell voltage acquisition module. The cell voltage acquisition module is connected to the positive and negative terminals of each cell in the battery pack, wherein the cell voltage acquisition module is connected to at least one terminal of each cell through the discharge module. In this technical solution, the cell voltage sampling module is used to acquire the cell voltage of each cell, and when the cell voltage of a target cell exceeds the target voltage of other cells, indicating that the cell voltage of the target cell is higher than that of other cells, the module controls the connection between the discharge module and the positive and negative terminals of the target cell, so that the cell and the discharge module form a current loop, thereby allowing the discharge module to consume the energy of the target cell, achieving the discharge of the target cell and reducing its cell voltage. By correcting the cells with excessively high cell voltages in the battery pack, the consistency of cell voltages in the battery pack is maintained to a certain extent.

[0104] Furthermore, in this application's technical solution, by externalizing the discharge module to the cell voltage acquisition module, not only can the size of the cell voltage acquisition module be reduced, but the heat generated by the discharge module during energy consumption can also be prevented from affecting the cell voltage acquisition module. This increases the output current from the cell to the discharge module, allowing the discharge module to accelerate the energy consumption efficiency of the cell, improve the cell's discharge efficiency, accelerate the voltage drop rate, and improve the cell's voltage balancing efficiency. In addition, externalizing the discharge module also frees its size from the constraints of the cell voltage acquisition module. This allows for an increase in the size of the discharge module, increasing its heat dissipation area, further increasing the cell's output current to the discharge module, improving the cell's discharge efficiency, and enhancing the cell's voltage balancing efficiency.

[0105] This application also provides an electric vehicle. The electric vehicle includes the battery management system provided in this application embodiment. In the battery management system provided in this application embodiment, the battery management circuit includes a discharge module and a cell voltage acquisition module. The cell voltage acquisition module is connected to the positive and negative terminals of each cell in the battery pack, wherein the cell voltage acquisition module is connected to at least one terminal of each cell through the discharge module. In this technical solution, the cell voltage sampling module is used to acquire the cell voltage of each cell, and when the cell voltage of a target cell exceeds the target voltage of other cells, indicating that the cell voltage of the target cell is higher than that of other cells, the discharge module is controlled to connect to the positive and negative terminals of the target cell, so that the cell and the discharge module form a current loop, thereby allowing the discharge module to consume the electrical energy of the target cell, realizing the discharge of the target cell, and achieving the purpose of reducing the cell voltage of the target cell. By correcting the cells with higher cell voltages in the battery pack, the consistency of cell voltages in the battery pack is maintained to a certain extent.

[0106] Furthermore, in this application's technical solution, by externalizing the discharge module to the cell voltage acquisition module, not only can the size of the cell voltage acquisition module be reduced, but the heat generated by the discharge module during energy consumption can also be prevented from affecting the cell voltage acquisition module. This increases the output current from the cell to the discharge module, allowing the discharge module to accelerate the energy consumption efficiency of the cell, improve the cell's discharge efficiency, accelerate the voltage drop rate, and improve the cell's voltage balancing efficiency. In addition, externalizing the discharge module also frees its size from the constraints of the cell voltage acquisition module. This allows for an increase in the size of the discharge module, increasing its heat dissipation area, further increasing the cell's output current to the discharge module, improving the cell's discharge efficiency, and enhancing the cell's voltage balancing efficiency.

[0107] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A battery management circuit, characterized in that, include: The discharge module and the cell voltage acquisition module are separately configured. The cell voltage acquisition module is connected to the positive and negative terminals of each cell in the battery pack through the discharge module; or, the cell voltage acquisition module is connected to one terminal of each cell, and the other terminal of each cell is connected to the cell voltage acquisition module through the discharge module. The cell voltage sampling module is used to collect the cell voltage of each cell, and when the cell voltage of the target cell exceeds the target voltage, it controls the connection between the discharge module and the positive and negative terminals of the target cell. The target voltage is the voltage of other cells in the battery pack except for the target cell. The target cell can be any cell in the battery pack. The discharge module is used to consume the electrical energy of the target battery cell when it is connected to the positive and negative terminals of the target battery cell.

2. The battery management circuit according to claim 1, characterized in that, The cell voltage acquisition module includes: an acquisition controller and multiple sampling ports, the multiple sampling ports being connected to the positive terminal of each cell and the negative terminal of the end cell, the end cell being a single battery cell directly connected to the negative terminal port of the battery pack; Each of the sampling ports is connected to the first port of the acquisition controller via a voltage sampling resistor. The acquisition controller is used to acquire the positive and negative voltages of each cell based on the resistance value of the voltage sampling resistor, and to calculate the cell voltage of each cell based on the positive and negative voltages of each cell. Each of the sampling ports is also directly connected to a second port of the acquisition controller, which is used to control the connection between the first target port and the second target port when the cell voltage of the target cell exceeds the target voltage. The first target port is the second port connected to the positive terminal of the target cell, and the second target port is the second port connected to the negative terminal of the target cell.

3. The battery management circuit according to claim 2, characterized in that, The data acquisition controller includes multiple switching components, each corresponding to a battery cell. Each of the switching devices is connected to two second ports that are respectively connected to the two poles of the corresponding battery cell. The switching device is used to connect the two connected second ports when the battery cell voltage of the corresponding battery cell exceeds the target voltage, and to disconnect the two connected second ports when the battery cell voltage of the corresponding battery cell does not exceed the target voltage.

4. The battery management circuit according to claim 3, characterized in that, The acquisition controller includes: a control module; The control module is connected to the first port and each of the switching devices. The control module is used to collect the positive and negative voltages of each cell, calculate the cell voltage of each cell, and output an on control signal to the target switching device corresponding to the target cell when the cell voltage of the target cell exceeds the target voltage, and output an off control signal to the target switching device when the cell voltage of the target cell does not exceed the target voltage. The switch is used to connect the two second ports under the control of the open control signal, and to disconnect the two second ports under the control of the close control signal.

5. The battery management circuit according to any one of claims 1 to 4, characterized in that, The discharge module includes: multiple discharge components; the multiple discharge components are connected to the cell voltage acquisition module, and are respectively connected to at least one of the positive and negative terminals of each cell.

6. The battery management circuit according to claim 5, characterized in that, The battery management circuit includes: a flexible circuit board (FPC) with multiple voltage sampling lines disposed on the FPC; The plurality of voltage sampling lines are all connected to the cell voltage acquisition module and are respectively connected to the positive and negative terminals of each cell. The voltage sampling line connected to at least one terminal of each cell is the discharge component, and the impedance value of the voltage sampling line of the discharge component is at least equal to the equalization resistance value. The equalization resistance value is determined based on the maximum operating voltage and the maximum equalization current of the cell. The maximum equalization current is a preset maximum value of the current flowing through the voltage sampling line.

7. The battery management circuit according to claim 6, characterized in that, The cell voltage acquisition module is integrated on the FPC.

8. The battery management circuit according to claim 5, characterized in that, The discharge component includes: discrete resistors.

9. The battery management circuit according to any one of claims 6 to 7, characterized in that, Each of the discharge components is connected to the positive terminal of a different cell or the negative terminal of the end cell.

10. A battery management system, characterized in that, include: A battery pack and a battery management circuit connected to the battery pack, wherein the battery management circuit is the circuit described in any one of claims 1 to 9.

11. An electric vehicle, characterized in that, include: The battery management system of claim 10.

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