Active balancing method circuit, method for battery cluster

Abstract

The application discloses a kind of active equalization method circuit, method of battery cluster.It includes battery cluster, switch module, rectifier module, variable pressure module and control module, battery cluster includes N battery module in series, the number of switch module is N+1;The first end of the Nth switch module is connected to the positive pole of the Nth battery module or the negative pole of the N-1th battery module, the second end of the even number switch module is connected to the first end of rectifier module, the second end of the odd number switch module is connected to the second end of rectifier module;The third end and the fourth end of rectifier module are electrically connected to the first end and the second end of variable pressure module respectively, the third end and the fourth end of variable pressure module are electrically connected to both ends of battery cluster respectively;Control module is electrically connected to battery module, switch module, rectifier module and variable pressure module respectively.By the active equalization circuit of battery cluster provided in the application, the circuit structure is simple, wiring is convenient, and wiring cost can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of batteries, and more specifically to an active balancing method circuit and method for battery clusters. Background Technology

[0002] Currently, as lithium-ion battery packs on the market are used for longer periods and the number of cycle discharges increases, the battery capacity or battery module will gradually become unbalanced due to the influence of design or the manufacturing process of individual cells. Active balancing of all batteries or battery modules would require very complex changes to the active balancing circuit and structure, resulting in extremely high costs. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defect that the active balancing circuit in the prior art is very complex, and to provide an active balancing method circuit and method for battery clusters.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] As a first aspect of the present invention, the present invention provides an active balancing circuit for a battery cluster, the active balancing circuit including a battery cluster, a switching module, a rectifier module, a transformer module and a control module, the battery cluster including N battery modules connected in series, the number of the switching modules being N+1, where N is a positive integer greater than or equal to 2;

[0006] The first terminal of the Nth switch module is connected to the positive terminal of the Nth battery module or to the negative terminal of the (N-1)th battery module; the second terminal of the even-numbered switch module is connected to the first terminal of the rectifier module; and the second terminal of the odd-numbered switch module is connected to the second terminal of the rectifier module.

[0007] The third and fourth terminals of the rectifier module are electrically connected to the first and second terminals of the transformer module, respectively, and the third and fourth terminals of the transformer module are electrically connected to the two ends of the battery pack, respectively.

[0008] The control module is electrically connected to the battery module, the switch module, the rectifier module, and the transformer module, respectively.

[0009] The control module is used to determine the target battery module according to the voltage of each battery module, turn on the switch module that is electrically connected to both ends of the target battery module, and charge or discharge the target battery module through the transformer module.

[0010] The rectifier module is used to pull up the voltage of the positive terminal of the target battery module, pull down the voltage of the negative terminal of the target battery module, and rectify the output or input power of the target battery module.

[0011] Optionally, each of the switching modules includes a first N-type MOSFET and a second N-type MOSFET;

[0012] The source of the first N-type MOS transistor serves as the second terminal of the switching module;

[0013] The drains of the first N-type MOS transistor and the drains of the second N-type MOS transistor are connected to each other;

[0014] The source of the second N-type MOS transistor serves as the first terminal of the switching module;

[0015] The gates of the first N-type MOS transistor and the second N-type MOS transistor are both connected to the control module.

[0016] Optionally, the rectifier module includes a first switching device, a second switching device, a third switching device, and a fourth switching device;

[0017] The first end of the first switching device is electrically connected to a voltage source, and the second end of the first switching device is connected to the first port;

[0018] The first terminal of the second switching device is electrically connected to a voltage source, and the second terminal of the second switching device also serves as the second terminal of the rectifier module;

[0019] The first end of the third switching device serves as the second end of the rectifier module, and the second end of the third switching device is electrically connected to the second end of the fourth switching device.

[0020] The first terminal of the fourth switching device serves as the first terminal of the rectifier module, and the second terminal of the fourth switching device is grounded.

[0021] The third terminals of the first switching device, the second switching device, the third switching device, and the fourth switching device are all electrically connected to the control module.

[0022] The control module is used to control the first switch device, the second switch device, the third switch device, and the fourth switch device to open or close according to the target battery module, so as to raise the positive electrode voltage of the target battery module and lower the negative electrode voltage of the battery module.

[0023] Optionally, the transformer module includes a first transformer unit, a second transformer unit, a third transformer unit, a first capacitor, and a second capacitor;

[0024] The first terminal of the first transformer unit is electrically connected to the third terminal of the rectifier module and the voltage source, and the second terminal of the first transformer unit is electrically connected to the fourth terminal of the rectifier module and ground.

[0025] The third and fourth terminals of the first transformer unit are respectively electrically connected to the first and second terminals of the third transformer unit;

[0026] The third and fourth terminals of the third transformer unit are electrically connected to the first and second terminals of the second transformer unit, respectively.

[0027] The third and fourth terminals of the second transformer unit are electrically connected to the first and last terminals of the battery pack, respectively.

[0028] The third transformer unit is used to convert the high voltage corresponding to the battery cluster to the low voltage corresponding to the target battery module.

[0029] Both the first transformer unit and the second transformer unit are used to convert the DC power on both sides of the third transformer unit into AC power to charge or discharge the target battery module.

[0030] The first terminal of the first capacitor serves as the first terminal of the transformer module, the second terminal of the first capacitor serves as the second terminal of the transformer module, the first terminal of the second capacitor serves as the third terminal of the transformer module, and the second terminal of the second capacitor serves as the fourth terminal of the transformer module.

[0031] Optionally, the first transformer unit includes a fifth switching device, a sixth switching device, a seventh switching device, and an eighth switching device.

[0032] The first end of the fifth switching device is connected to the first end of the sixth switching device, and the second end of the fifth switching device is electrically connected to the first end of the seventh switching device and the first end of the third transformer unit.

[0033] The first terminal of the sixth switching device is electrically connected to the third terminal of the rectifier module, and the second terminal of the sixth switching device is electrically connected to the first terminal of the eighth switching device and the second terminal of the third transformer unit.

[0034] The second terminal of the seventh switching device is electrically connected to the second terminal of the eighth switching device;

[0035] The second terminal of the eighth switching device is electrically connected to the fourth terminal of the rectifier module;

[0036] The third terminals of the fifth switch device, the sixth switch device, the seventh switch device, and the eighth switch device are all connected to the control module.

[0037] The control module is used to control the opening and closing of the fifth, sixth, seventh, and eighth switching devices.

[0038] Optionally, the second transformer unit includes a ninth switching device, a tenth switching device, an eleventh switching device, and a twelfth switching device.

[0039] The first end of the ninth switching device is electrically connected to one end of the battery cluster and the first end of the tenth switching device, and the second end of the ninth switching device is electrically connected to the third end of the third transformer unit and the first end of the eleventh switching device.

[0040] The second terminal of the tenth switching device is electrically connected to the fourth terminal of the transformer module and the first terminal of the twelfth switching device;

[0041] The second end of the eleventh switching device is electrically connected to the other end of the battery cluster and the second end of the twelfth switching device.

[0042] The third terminals of the ninth switch device, the tenth switch device, the eleventh switch device, and the twelfth switch device are all electrically connected to the control module.

[0043] The control module is used to control the opening and closing of the ninth switch device, the tenth switch device, the eleventh switch device, and the twelfth switch device.

[0044] Optionally, the control module includes a DC / DC controller, which controls the first transformer unit and the second transformer unit to rectify the current, and controls the third transformer unit to convert the high voltage corresponding to the battery cluster to the low voltage corresponding to the target battery module.

[0045] Optionally, the control module is used to acquire the voltage difference between battery modules to obtain the voltage value of each battery module.

[0046] As a second aspect of the present invention, the present invention provides an active balancing method for battery clusters, the active balancing method being implemented based on the active balancing circuit of the battery cluster of the first aspect of the present invention, wherein the battery cluster includes battery modules with a different number of batteries than at least one and the remaining battery modules.

[0047] The active balancing method includes:

[0048] Obtain the number of batteries included in each battery module and the standard discharge voltage threshold;

[0049] The discharge voltage threshold corresponding to each battery module is determined based on the number of batteries and the standard discharge voltage threshold.

[0050] Battery modules with voltages greater than the discharge voltage threshold are identified as target discharge battery modules;

[0051] The target discharge battery module is discharged.

[0052] Optionally, the active balancing method further includes:

[0053] Obtain the standard charging voltage;

[0054] The charging voltage threshold corresponding to each battery module is determined based on the number of batteries and the standard charging voltage threshold.

[0055] Battery modules with voltages lower than the charging voltage threshold are identified as target rechargeable battery modules;

[0056] The target rechargeable battery module is charged.

[0057] The positive and progressive effects of this invention are as follows: the active balancing circuit for battery clusters provided by this invention has a simple circuit structure, is easy to wire, and can effectively reduce wiring costs.

[0058] The active balancing method for battery clusters provided by this invention can accurately determine whether battery modules with different numbers of batteries need to be charged and discharged. When the battery cluster is balanced, it can accurately determine whether each battery module needs to be charged and discharged, so as to accurately achieve the balance of power of each battery module in the battery cluster. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the first structure of the active balancing circuit for the battery cluster in Embodiment 1 of the present invention.

[0060] Figure 2 This is a schematic diagram of the second structure of the active balancing circuit for the battery cluster in Embodiment 1 of the present invention.

[0061] Figure 3 This is a schematic diagram of the third structure of the active balancing circuit for the battery cluster in Embodiment 1 of the present invention.

[0062] Figure 4 This is a schematic diagram of the first process of the active balancing method for battery clusters in Embodiment 2 of the present invention.

[0063] Figure 5 This is a schematic diagram of the second process of the active balancing method for battery clusters in Embodiment 2 of the present invention. Detailed Implementation

[0064] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments.

[0065] Example 1

[0066] Please see Figure 1This embodiment provides an active balancing circuit for battery clusters.

[0067] The active balancing circuit includes a battery cluster 1, a switching module 2, a rectifier module 3, a transformer module 4, and a control module 5. The battery cluster 1 includes N battery modules 11 connected in series, and the number of switching modules 2 is N+1, where N is a positive integer greater than or equal to 2.

[0068] The first terminal of the Nth switch module is connected to the positive terminal of the Nth battery module or the negative terminal of the (N-1)th battery module, and the second terminal of the even-numbered switch module is connected to the first terminal of the rectifier module 3 (see details). Figure 1 Point A in the diagram), the second terminal of the odd-numbered switch module is connected to the second terminal of rectifier module 3 (see point A in the diagram for details). Figure 1 (Point B in the middle);

[0069] The third and fourth terminals of the rectifier module 3 are electrically connected to the first and second terminals of the transformer module 4, respectively, and the third and fourth terminals of the transformer module 4 are electrically connected to the two ends of the battery cluster 1, respectively.

[0070] The control module 5 is electrically connected to the battery module 11, the switch module 2, the rectifier module 3, and the transformer module 4 respectively;

[0071] The control module 5 is used to determine the target battery module based on the voltage of each battery module 11, turn on the switch module 2 that is electrically connected to both ends of the target battery module, and charge or discharge the target battery module through the transformer module 4.

[0072] The rectifier module 3 is used to pull up the voltage of the positive terminal of the target battery module, pull down the voltage of the negative terminal of the target battery module 11, and rectify the output or input power of the target battery module.

[0073] In this embodiment, N+1 switch modules are sequentially connected to the first terminal of the first battery module, the first terminal of the second battery module, and so on, up to the first terminal and the second terminal of the Nth battery module (here, the first terminal is either positive or negative, and the second terminal is the other terminal referred to by the first terminal). Therefore, each battery module 11 has one switch module 2 connected to both its positive and negative terminals. For example, the first terminal of the xth battery module is connected to the xth switch module, and the second terminal is connected to the x+1th switch module (it should be noted that x is a positive integer less than or equal to N). Among the xth and x+1th switch modules, the even-numbered switch module is connected to the first terminal of the rectifier module 3, and the second terminal of the odd-numbered switch module is connected to the second terminal of the rectifier module 3. That is, when one terminal of the xth battery module is connected to the first terminal of the rectifier module 3, the other terminal of the xth battery module will be connected to the second terminal of the rectifier module 3.

[0074] By connecting N series-connected battery modules 11, N+1 switch modules, and the first and second ends of the rectifier module 3, the complexity of wiring can be greatly reduced, and wiring costs can be effectively reduced.

[0075] It should be noted that in the above embodiments, the battery module 11 may include a plurality of batteries connected in series and / or in parallel. The descriptions of "the Nth" and "the xth" in this invention are for the purpose of describing the connection relationship between the various components and should not be construed as limiting "the Nth" or "the xth".

[0076] Please see Figure 2 In an optional embodiment, each switch module 2 includes a first N-type MOSFET 21 and a second N-type MOSFET 22;

[0077] The source of the first N-type MOSFET 21 serves as the second terminal of the switching module 2;

[0078] The drains of the first N-type MOSFET 21 and the drains of the second N-type MOSFET 22 are connected to each other;

[0079] The source of the second N-type MOSFET 22 serves as the first terminal of the switching module 2;

[0080] The gates of the first N-type MOSFET 21 and the second N-type MOSFET 22 are both connected to the control module 5.

[0081] In this embodiment, the control module 5 can quickly control the path between the battery module 11 and the rectifier module 3 through the first N-type MOS transistor 21 and the second N-type MOS transistor 22, so as to meet the power balance requirements of the battery module 11 in the battery cluster 1.

[0082] Please see Figure 3 In an optional embodiment, the rectifier module 3 includes a first switching device N1, a second switching device N2, a third switching device N3, and a fourth switching device N4.

[0083] The first terminal of the first switching device N1 is electrically connected to the voltage source Bvdd, and the second terminal of the first switching device N1 is connected to the first port.

[0084] The first terminal of the second switching device N2 is electrically connected to the voltage source Bvdd, and the second terminal of the second switching device N2 also serves as the second terminal of the rectifier module 3.

[0085] The first end of the third switching device N3 serves as the second end of the rectifier module 3, and the second end of the third switching device N3 is electrically connected to the second end of the fourth switching device N4.

[0086] The first terminal of the fourth switching device N4 serves as the first terminal of the rectifier module 3, and the second terminal of the fourth switching device N4 is grounded to Bgnd.

[0087] The third terminal of the first switching device N1, the third terminal of the second switching device N2, the third terminal of the third switching device N3, and the third terminal of the fourth switching device N4 are all electrically connected to the control module 5.

[0088] The control module 5 is used to control the first switch device N1, the second switch device N2, the third switch device N3 and the fourth switch device N4 to open or close according to the target battery module, so as to raise the positive electrode voltage of the target battery module and lower the negative electrode voltage of the battery module.

[0089] In this embodiment, after being rectified and output to voltage source Bvdd and ground Bgnd by the first switching device N1, the third switching device N3 or the second switching device N2 and the fourth switching device N4, the positive voltage of the target battery module can be pulled up to the voltage of voltage source Bvdd, and the negative voltage can be pulled down to zero, so that the voltage difference between the positive and negative terminals of the target battery module meets the requirements.

[0090] In an optional embodiment, the transformer module 4 includes a first transformer unit 41, a second transformer unit 42, a third transformer unit 43, a first capacitor, and a second capacitor;

[0091] The first terminal of the first transformer unit 41 is electrically connected to the third terminal of the rectifier module 3 and the voltage source Bvdd, and the second terminal of the first transformer unit 41 is electrically connected to the fourth terminal of the rectifier module 3 and the ground Bgnd.

[0092] The third and fourth terminals of the first transformer unit 41 are respectively electrically connected to the first and second terminals of the third transformer unit 43.

[0093] The third and fourth terminals of the third transformer unit 43 are electrically connected to the first and second terminals of the second transformer unit 42, respectively.

[0094] The third and fourth terminals of the second transformer unit 42 are electrically connected to the first and last terminals of the battery pack 1, respectively.

[0095] The third transformer unit 43 is used to convert the high voltage corresponding to the battery cluster 1 to the low voltage corresponding to the target battery module.

[0096] Both the first transformer unit 41 and the second transformer unit 42 are used to convert the DC power on both sides of the third transformer unit 43 into AC power to charge or discharge the target battery module.

[0097] The first terminal of the first capacitor serves as the first terminal of the transformer module 4, the second terminal of the first capacitor serves as the second terminal of the transformer module 4, the first terminal of the second capacitor serves as the third terminal of the transformer module 4, and the second terminal of the second capacitor serves as the fourth terminal of the transformer module 4.

[0098] In an optional embodiment, the first transformer unit 41 includes a fifth switching device N5, a sixth switching device N6, a seventh switching device N7, and an eighth switching device N8.

[0099] The first end of the fifth switching device N5 is connected to the first end of the sixth switching device N6, and the second end of the fifth switching device N5 is electrically connected to the first end of the seventh switching device N7 and the first end of the third transformer unit 43.

[0100] The first terminal of the sixth switching device N6 is electrically connected to the third terminal of the rectifier module 3, and the second terminal of the sixth switching device N6 is electrically connected to the first terminal of the eighth switching device N8 and the second terminal of the third transformer unit 43.

[0101] The second terminal of the seventh switching device N7 is electrically connected to the second terminal of the eighth switching device N8;

[0102] The second terminal of the eighth switching device N8 is electrically connected to the fourth terminal of the rectifier module 3;

[0103] The third terminal of the fifth switch device N5, the third terminal of the sixth switch device N6, the third terminal of the seventh switch device N7, and the third terminal of the eighth switch device N8 are all connected to the control module 5.

[0104] The control module 5 is used to control the opening and closing of the fifth switch device N5, the sixth switch device N6, the seventh switch device N7 and the eighth switch device N8.

[0105] In this embodiment, periodically turning on the fifth switching device N5, the eighth switching device N8, or the sixth switching device N6 and the seventh switching device N7 can boost the voltage in the first transformer unit 41 and transmit it to the second transformer unit 42 through the three transformer units 43, or depress the voltage in the second transformer unit 42 and transmit it to the first transformer unit 41.

[0106] In an optional embodiment, the second transformer unit 42 includes a ninth switching device N9, a tenth switching device N10, an eleventh switching device N11, and a twelfth switching device N12.

[0107] The first end of the ninth switching device N9 is electrically connected to one end of the battery cluster 1 and the first end of the tenth switching device N10, and the second end of the ninth switching device N9 is electrically connected to the third end of the third transformer unit 43 and the first end of the eleventh switching device N11.

[0108] The second terminal of the tenth switch device N10 is electrically connected to the fourth terminal of the transformer module 4 and the first terminal of the twelfth switch device N12;

[0109] The second terminal of the eleventh switching device N11 is electrically connected to the other terminal of the battery cluster 1 and the second terminal of the twelfth switching device N12;

[0110] The third terminal of the ninth switch device N9, the third terminal of the tenth switch device N10, the third terminal of the eleventh switch device N11, and the third terminal of the twelfth switch device N12 are all electrically connected to the control module 5.

[0111] The control module 5 is used to control the opening and closing of the ninth switch device N9, the ninth switch device N10, the eleventh switch device N11, and the ninth switch device N12.

[0112] In this embodiment, periodically turning on the ninth switch device N9, the twelfth switch device N12, or the tenth switch device N10 and the eleventh switch device N11 can transmit the voltage in the second transformer unit 42 to the first transformer unit 41 through the three transformer units 43, or transmit the voltage of the first transformer unit 41 to the second transformer unit 42.

[0113] In the above optional embodiments, the first switching device N1 to the twelfth switching device N12 can all be N-type MOS transistors, wherein the first terminal of the first to twelfth switching devices N12 can all be the source, the second terminal of the first to twelfth switching devices N12 can all be the drain, and the third terminal of the first to twelfth switching devices N12 can all be the gate.

[0114] In an optional embodiment, the control module 5 includes a DC / DC controller, which controls the first transformer unit and the second transformer unit to rectify the current and controls the third transformer unit to convert the high voltage corresponding to the battery cluster 1 to the low voltage corresponding to the target battery module.

[0115] In an optional embodiment, the third transformer unit 43 may be a transformer, and the turns ratio of the second transformer unit 42 side to the first transformer unit 41 side in the third transformer unit 43 may be n:1.

[0116] In an optional embodiment, the control module 5 is used to obtain the voltage difference between the battery modules 11 to obtain the voltage value of each battery module 11.

[0117] In the above embodiments, a voltage acquisition device can be connected in parallel across the two ends of each battery module 11. The voltage acquisition device can obtain the voltage difference between the battery modules 11. Specifically, it can obtain the first voltage of the first battery module 11, and then obtain the second voltage, which is the sum of the first and second battery modules. Finally, the voltage of the second battery module is determined by the first and second voltages. The voltage values ​​of the other battery modules are not described here.

[0118] The active balancing circuit for battery clusters provided by this invention has a simple circuit structure and convenient wiring, which can effectively reduce wiring costs.

[0119] Example 2

[0120] Please see Figure 5 This embodiment provides an active balancing method for battery clusters.

[0121] The active balancing method is implemented based on the active balancing circuit of the battery cluster in Embodiment 1, wherein the battery cluster includes battery modules with a different number of batteries than at least one and the rest of the battery modules.

[0122] Please see Figure 4 Active balancing methods include:

[0123] S1. Obtain the number of batteries included in each battery module and the standard discharge voltage threshold.

[0124] S2. Determine the discharge voltage threshold for each battery module based on the number of batteries and the standard discharge voltage threshold.

[0125] S3. Identify battery modules with voltages greater than the discharge voltage threshold as target discharge battery modules;

[0126] S4. Discharge the target battery module.

[0127] In this embodiment, for example, the standard discharge voltage threshold is 3V, corresponding to one battery module. If a battery module contains three batteries, the discharge voltage threshold for that module can be set to 9V. If the voltage of the battery module is below 9V, then that battery can be identified as the target discharge battery, and discharge can be performed on it.

[0128] Please see Figure 5 In an optional embodiment, the active balancing method for battery clusters further includes:

[0129] S11. Obtain the number of batteries and standard charging voltage included in each battery module;

[0130] S21. Determine the charging voltage threshold for each battery module based on the number of batteries and the standard discharge voltage threshold.

[0131] S31. Identify battery modules with voltages lower than the charging voltage threshold as target rechargeable battery modules;

[0132] S41. Charge the target rechargeable battery module.

[0133] In this embodiment, the only difference from the previous embodiment is the charging voltage threshold. For example, the standard charging voltage threshold is 1.5V, corresponding to one battery in the battery module (the standard charging voltage threshold could also be 15V, but that would correspond to ten batteries in the battery module). If a battery module has three batteries, then the corresponding charging voltage threshold for that battery module is 4.5V. If the voltage of this battery module is lower than 4.5V, it can be identified as the target rechargeable battery module.

[0134] In the above embodiments, due to various reasons (such as battery failure in different battery modules or a particular battery module being responsible for fast charging), the number of batteries included in the battery modules within a battery cluster may vary. The method described above allows for accurate determination of whether each battery module needs charging or discharging.

[0135] In an optional embodiment, the steps of determining the target discharge battery module and the target rechargeable battery module can be performed after preset conditions are met. The preset conditions may be: a first time after charging or discharging the battery module (e.g., after charging a certain battery module for 3 hours); or a second time after charging or discharging the entire battery cluster.

[0136] The active balancing method for battery clusters provided by this invention can accurately determine whether battery modules with different numbers of batteries need to be charged and discharged. When the battery cluster is balanced, it can accurately determine whether each battery module needs to be charged and discharged, so as to accurately achieve the balance of power of each battery module in the battery cluster.

[0137] In the above embodiments, it should be noted that those skilled in the art can readily replace "greater than" or "less than" in this invention with "equal to". Furthermore, the technical solutions obtained by replacing them with "equal to" are substantially the same as those of this invention, achieving substantially the same functions and technical effects. Even if a product or method differs from the technical solutions described in this invention in that it uses "greater than", "less than", or "equal to", it should still be considered to fall within the protection scope of the claims of this invention.

[0138] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. An active balancing method for battery clusters, characterized in that, The active balancing method is implemented based on the active balancing circuit of the battery cluster, which includes battery modules with a different number of batteries than at least one and the rest of the battery modules. The active balancing method includes: Obtain the number of batteries included in each battery module and the standard discharge voltage threshold; The discharge voltage threshold corresponding to each battery module is determined based on the number of batteries and the standard discharge voltage threshold. Battery modules with voltages greater than the discharge voltage threshold are identified as target discharge battery modules; Discharge the target battery module; The active balancing circuit of the battery cluster includes a battery cluster, a switching module, a rectifier module, a transformer module, and a control module. The battery cluster includes N battery modules connected in series, and the number of switching modules is N+1, where N is a positive integer greater than or equal to 2. The first terminal of the Nth switch module is connected to the positive terminal of the Nth battery module or to the negative terminal of the (N-1)th battery module; the second terminal of the even-numbered switch module is connected to the first terminal of the rectifier module; and the second terminal of the odd-numbered switch module is connected to the second terminal of the rectifier module. The third and fourth terminals of the rectifier module are electrically connected to the first and second terminals of the transformer module, respectively, and the third and fourth terminals of the transformer module are electrically connected to the two ends of the battery pack, respectively. The control module is electrically connected to the battery module, the switch module, the rectifier module, and the transformer module, respectively. The control module is used to determine the target battery module according to the voltage of each battery module, turn on the switch module that is electrically connected to both ends of the target battery module, and charge or discharge the target battery module through the transformer module. The rectifier module is used to pull up the voltage of the positive terminal of the target battery module, pull down the voltage of the negative terminal of the target battery module, and rectify the current output or input of the target battery module.

2. The active balancing method for battery clusters as described in claim 1, characterized in that, The active balancing method also includes: Obtain the standard charging voltage; The charging voltage threshold corresponding to each battery module is determined based on the number of batteries and the standard charging voltage threshold. Battery modules with voltages lower than the charging voltage threshold are identified as target rechargeable battery modules; The target rechargeable battery module is charged.

3. The active balancing method for battery clusters as described in claim 1, characterized in that, Each of the switching modules includes a first N-type MOSFET and a second N-type MOSFET; The source of the first N-type MOS transistor serves as the second terminal of the switching module; The drains of the first N-type MOS transistor and the drains of the second N-type MOS transistor are connected to each other; The source of the second N-type MOS transistor serves as the first terminal of the switching module; The gates of the first N-type MOS transistor and the second N-type MOS transistor are both connected to the control module.

4. The active balancing method for battery clusters as described in claim 1, characterized in that, The rectifier module includes a first switching device, a second switching device, a third switching device, and a fourth switching device; The first end of the first switching device is electrically connected to a voltage source, and the second end of the first switching device is connected to the first port. The first terminal of the second switching device is electrically connected to a voltage source, and the second terminal of the second switching device also serves as the second terminal of the rectifier module; The first end of the third switching device serves as the second end of the rectifier module, and the second end of the third switching device is electrically connected to the second end of the fourth switching device. The first terminal of the fourth switching device serves as the first terminal of the rectifier module, and the second terminal of the fourth switching device is grounded. The third terminals of the first switching device, the second switching device, the third switching device, and the fourth switching device are all electrically connected to the control module. The control module is used to control the first switch device, the second switch device, the third switch device, and the fourth switch device to open or close according to the target battery module, so as to raise the positive electrode voltage of the target battery module and lower the negative electrode voltage of the target battery module.

5. The active balancing method for battery clusters as described in claim 1, characterized in that, The transformer module includes a first transformer unit, a second transformer unit, a third transformer unit, a first capacitor, and a second capacitor; The first terminal of the first transformer unit is electrically connected to the third terminal of the rectifier module and the voltage source, and the second terminal of the first transformer unit is electrically connected to the fourth terminal of the rectifier module and ground. The third and fourth terminals of the first transformer unit are respectively electrically connected to the first and second terminals of the third transformer unit; The third and fourth terminals of the third transformer unit are electrically connected to the first and second terminals of the second transformer unit, respectively. The third and fourth terminals of the second transformer unit are electrically connected to the first and last terminals of the battery pack, respectively. The third transformer unit is used to convert the high voltage corresponding to the battery cluster to the low voltage corresponding to the target battery module. Both the first transformer unit and the second transformer unit are used to convert the DC power on both sides of the third transformer unit into AC power to charge or discharge the target battery module. The first terminal of the first capacitor serves as the first terminal of the transformer module, the second terminal of the first capacitor serves as the second terminal of the transformer module, the first terminal of the second capacitor serves as the third terminal of the transformer module, and the second terminal of the second capacitor serves as the fourth terminal of the transformer module.

6. The active balancing method for battery clusters as described in claim 5, characterized in that, The first transformer unit includes a fifth switching device, a sixth switching device, a seventh switching device, and an eighth switching device; The first end of the fifth switching device is connected to the first end of the sixth switching device, and the second end of the fifth switching device is electrically connected to the first end of the seventh switching device and the first end of the third transformer unit. The first terminal of the sixth switching device is electrically connected to the third terminal of the rectifier module, and the second terminal of the sixth switching device is electrically connected to the first terminal of the eighth switching device and the second terminal of the third transformer unit. The second terminal of the seventh switching device is electrically connected to the second terminal of the eighth switching device; The second terminal of the eighth switching device is electrically connected to the fourth terminal of the rectifier module; The third terminals of the fifth switch device, the sixth switch device, the seventh switch device, and the eighth switch device are all connected to the control module. The control module is used to control the opening and closing of the fifth, sixth, seventh, and eighth switching devices.

7. The active balancing method for battery clusters as described in claim 5, characterized in that, The second transformer unit includes a ninth switching device, a tenth switching device, an eleventh switching device, and a twelfth switching device; The first end of the ninth switching device is electrically connected to one end of the battery cluster and the first end of the tenth switching device, and the second end of the ninth switching device is electrically connected to the third end of the third transformer unit and the first end of the eleventh switching device. The second terminal of the tenth switching device is electrically connected to the fourth terminal of the transformer module and the first terminal of the twelfth switching device; The second end of the eleventh switching device is electrically connected to the other end of the battery cluster and the second end of the twelfth switching device. The third terminals of the ninth switch device, the tenth switch device, the eleventh switch device, and the twelfth switch device are all electrically connected to the control module. The control module is used to control the opening and closing of the ninth switch device, the tenth switch device, the eleventh switch device, and the twelfth switch device.

8. The active balancing method for battery clusters as described in claim 5, characterized in that, The control module includes a DC / DC controller, which controls the first transformer unit and the second transformer unit to rectify the current and controls the third transformer unit to convert the high voltage corresponding to the battery cluster to the low voltage corresponding to the target battery module.

9. The active balancing method for battery clusters as described in claim 1, characterized in that, The control module is used to acquire the voltage difference between battery modules in order to obtain the voltage value of each battery module.

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