An active equalization control circuit, equalization control method and equalizer

Abstract

This invention relates to the field of battery balancing technology, and more particularly to an active balancing control circuit, balancing control method, and balancing instrument for balancing a battery string consisting of N battery cells connected in series, the battery string being divided into M battery groups; comprising: (N+1) channel selection switches, connected to the N battery cells in the battery string, corresponding to the M groups of channel selection switches; M groups of group number selection switches, connected to the M groups of channel selection switches; and a polarity selection switch, one side of which is connected to the DC-DC power supply terminal, and the other side of which is connected to the group number selection switch group, for selectively connecting odd-numbered or even-numbered channel selection switches. The purpose of this invention is to provide an active balancing control circuit, balancing control method, and balancing instrument. The technical solution provided by this invention solves the problem that current polarity selection and channel selection methods cannot meet the demand for increasing the number of battery cells in energy storage packs.

Description

Technical Field

[0001] This invention relates to the field of battery balancing technology, and in particular to an active balancing control circuit, a balancing control method, and a balancing device. Background Technology

[0002] Battery equalization is a method of actively balancing individual capacity differences and voltage differences caused by self-discharge rate during battery use. It keeps the voltage deviation of lithium-ion battery cells or battery packs within the expected range, thereby ensuring that each individual battery cell remains in the same state during normal use and avoiding overcharging and over-discharging.

[0003] Active balancing is a process that utilizes the differences between battery cells within the battery pack to actively balance the battery pack regardless of whether it is charging, discharging, or being stored, in order to eliminate various inconsistencies that arise after the battery pack is assembled and during use.

[0004] Figure 1 This is a block diagram of the current mainstream DC-DC active balancing channel selection control circuit. Because the battery cells are connected in series, the polarity of each cell is relative; for example, the positive terminal of one cell is the negative terminal of an adjacent cell. Therefore, in the channel selection control process, odd and even serial numbers are used to distinguish the cells.

[0005] Figure 1 PLUS is the positive terminal; MINUS is the negative terminal; to the left of PLUS and MINUS is the DC-DC power supply, used to balance the battery cells; the left frame contains the polarity selection switch, used to select the odd or even numbered battery cell, and the right frame contains the channel selection switch, used to select the specific numbered battery cell for balancing.

[0006] If the input signals of G55 and G54 are turned on, EVEN2 and ODD2 will be turned on. At this time, the positive and negative terminals are connected to the three odd-numbered cells C1, C3 and C5. Then, the cell to be turned on is selected by the channel selection switches Q1, Q3 and Q5.

[0007] Currently, the industry uses MOSFETs as switching transistors for both polarity selection switches and channel selection switches. The maximum drain-source voltage rating of surface-mount MOSFETs is currently 150V. With a derating ratio of 0.75 and a battery Vcell voltage of 3.5V, the maximum number of channels that can be designed is calculated as (n-1)*Vcell. Figure 1 The scheme shown can only support a maximum of 31 strings. However, the mainstream number of strings in current energy storage battery packs is 16, 48, 52, and 64, so it cannot meet the current development requirements of energy storage battery packs. Summary of the Invention

[0008] The purpose of this invention is to provide an active equalization control circuit, equalization control method, and equalizer. The technical solution provided by this invention solves the problem that the current polarity selection and channel selection cannot meet the demand for increasing the number of series in energy storage battery packs.

[0009] To address the aforementioned technical problems, this invention provides an active balancing control circuit for balancing a battery string consisting of N battery cells connected in series, the battery string being divided into M battery groups; wherein N and M are positive integers greater than or equal to 2; comprising: (N+1) channel selection switches are connected to N battery cells in the battery string, and are divided into M groups of channel selection switches corresponding to the battery pack, for selectively connecting one or more of the battery cells; M group number selection switch group, which is connected to M group channel selection switch group, is used to selectively access one or more of the channel selection switch groups; A polarity selection switch, one side of which is connected to the DC-DC power supply terminal and the other side of which is connected to the group number selection switch group, is used to selectively connect to the odd-numbered channel selection switch or the even-numbered channel selection switch; The active balancing control circuit connects the polarity selection switch, the group number selection switch group, and the channel selection switch in sequence to enable at least one or more battery cells in a group of battery packs to form a balancing loop.

[0010] Preferably, the battery pack is composed of one or more battery cells connected in series.

[0011] Preferably, the polarity selection switch includes two polarity switch groups composed of two MOS transistors, namely the first polarity switch group and the second polarity switch group. The sources of the two MOSFETs in the first polarity switch group are shorted and connected to the positive terminal of the DC-DC power supply to form the positive input terminal; the sources of the two MOSFETs in the second polarity switch group are shorted and connected to the negative terminal of the DC-DC power supply to form the negative input terminal. The drains of the two MOSFETs in the two polarity switch groups are shorted to form the ODD output terminal and the EVEN output terminal.

[0012] Preferably, the group number selection switch group includes two groups of group number selection switches; the input terminals of the two groups of selection switches are respectively connected to the ODD output terminal and the EVEN output terminal, and the output terminals are respectively connected to the odd-numbered channel selection switch and the even-numbered channel selection switch in the corresponding group.

[0013] Preferably, the selection switch for the channel selection switch and the group number selection switch includes two MOS transistors connected back-to-back in series.

[0014] Preferably, a single channel selection switch is shared between two adjacent battery packs and between two adjacent group number selection switches.

[0015] The aforementioned active balancing control circuit divides the battery string into M battery groups, sequentially connecting a polarity selection switch, a group number selection switch, and a channel selection switch. It connects at least one or more battery cells in each group to form a balancing loop. Calculations show that a surface-mount MOS can support a maximum of 31 battery cells. The active balancing control circuit provided by this invention, through three layers of selection (polarity selection switch, group number selection switch, and channel selection switch), controls the number of battery cells simultaneously balanced to within 31. In the circuit's connection structure, the number of battery cells in a battery string theoretically has no upper limit; it only needs to ensure that the number of battery cells simultaneously balanced is within 31 after the three layers of selection. Therefore, it can meet the current mainstream battery pack string counts of 16, 48, 52, and 64 strings, and further satisfy the development requirements of battery packs with even more strings.

[0016] Based on the above-described active equalization control circuit, the present invention also provides an active equalization control method, comprising the following steps: S100. Encode the N battery cells in the battery string in sequence to form M battery groups; S200: Determine the code and group of the battery cell whose difference between the individual cell voltage value and the preset value in the battery string is greater than a preset threshold; S300: Connect the corresponding polarity selection switch, group number selection switch group and channel selection switch according to the battery cell code and group, so that the DC-DC power supply terminal and the battery cell obtained in step S200 form an equalization circuit. S400: Real-time detection of the individual cell voltage value of the battery cell obtained in step S200, and disconnecting the channel selection switch of the battery cell whose individual cell voltage value is less than the preset value, until the difference between the individual cell voltage value and the preset value of all battery cells is less than the preset threshold.

[0017] Preferably, in step S300, the corresponding polarity selection switch, group number selection switch group, and channel selection switch are connected according to the battery cell's code and group; including: S301. If the obtained code is odd, the ODD output terminal of the first polarity switch group in the polarity selection switch is turned on, and the EVEN output terminal of the second polarity switch group is turned on. S302. If the obtained code is even, the EVEN output terminal of the first polarity switch group of the polarity selection switch is turned on, and the ODD output terminal of the second polarity switch group is turned on. S303. Select the switch group based on the obtained group number; S304. Turn on the corresponding channel selection switch according to the obtained code.

[0018] Preferably, in step S300, if the obtained codes have both odd and even numbers, the number of odd codes and the number of even codes are determined. If the number of odd codes is greater than the number of even codes, then step S301 is executed first, followed by step S302. If the number of even codes is greater than the number of odd codes, then step S302 is executed first, followed by step S301. In step S304, the channel selection switch corresponding to the encoding parity number is turned off.

[0019] Based on the active balancing control circuit of the present invention, the above-mentioned active balancing control method can accurately achieve balanced control of battery cells while meeting the requirements of the current multiple series of battery packs.

[0020] Finally, the present invention also provides an active equalizer, including the active equalization control circuit described in any of the above claims.

[0021] The active equalizer provided by this invention can handle application scenarios involving equalization control of multiple battery packs in series. Attached Figure Description

[0022] Figure 1 This is a block diagram of the current DC-DC type active equalizer channel selection control circuit. Figure 2 This is a block diagram of the active equalization control circuit in an embodiment of the present invention; Figure 3 This is a partial circuit diagram of the active equalization control circuit in an embodiment of the present invention. Figure 1 ; Figure 4 This is a partial circuit diagram of the active equalization control circuit in an embodiment of the present invention. Figure 2 Figure 5 This is a circuit diagram of the polarity selection switch in the active equalization control circuit of this invention. Figure 6 This is an embodiment of the present invention. Figure 3 Partial schematic diagram at point A in the middle; Figure 7 This is a flowchart of the active balancing control method according to an embodiment of the present invention; Figure 8 This is a flowchart of step S300 in the active balancing control method of this invention. Figure 9 This is a circuit diagram showing the connection between the first group number selection switch group and the channel selection switch in an embodiment of the present invention; Figure 10This is a circuit diagram showing the connection between the second group number selection switch group and the channel selection switch in an embodiment of the present invention. Figure 11 This is a circuit diagram showing the connection between the third group number selection switch group and the channel selection switch in an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] This embodiment provides an active balancing control circuit for series-connected batteries.

[0026] Currently, battery balancing control circuits use MOSFETs as switching transistors for both polarity selection and channel selection switches. The maximum drain-source voltage rating of surface-mount MOSFETs is 150V. With a derating ratio of 0.75 and a battery Vcell voltage of 3.5V, the maximum number of channels that can be designed is calculated as (n-1)*Vcell. Figure 1 The scheme shown can only support a maximum of 31 strings. However, the mainstream number of strings in current energy storage battery packs is 16, 48, 52, and 64, so it cannot meet the current development requirements of energy storage battery packs.

[0027] To address the aforementioned technical problems, this embodiment provides an active balancing control circuit for balancing a battery string consisting of N battery cells connected in series. The battery string is divided into M groups, where N and M are positive integers greater than or equal to 2, and M is not greater than N. For example, if the battery string uses 10 battery cells, it can be divided into 2 to 10 groups; if the battery string uses 20 battery cells, it can be divided into 2 to 20 groups, and so on.

[0028] Please see Figure 2-4 The active equalization control circuit provided in this embodiment specifically includes: (N+1) channel selection switches, M groups of group number selection switches, and polarity selection switches.

[0029] Among them, there are (N+1) channel selection switches, which are connected to N battery cells in the battery string. They are divided into M groups of channel selection switches corresponding to the battery pack, which are used to selectively connect one or more battery cells. M group number selection switch group, which is connected to M group channel selection switch group, is used to selectively connect one or more groups of channel selection switch groups; The polarity selection switch has one side connected to the DC-DC power supply terminal and the other side connected to the group number selection switch group, used to selectively connect either the odd-numbered channel selection switch or the even-numbered channel selection switch.

[0030] The active balancing control circuit provided in this embodiment connects the polarity selection switch, the group number selection switch group, and the channel selection switch in sequence during balancing control. Through the three-layer selection of polarity selection, group number selection, and channel selection, it connects at least one or more battery cells in a group of battery packs to form a balancing loop.

[0031] Specifically, the active equalization control circuit provided in this embodiment, such as Figure 5 As shown, its polarity selection switch includes two polarity switch groups composed of two MOSFETs, namely the first polarity switch group Q55 and the second polarity switch group Q54.

[0032] In terms of connection structure, the sources of the two MOSFETs in the first polarity switch group Q55 are shorted and connected to the positive terminal PLUS of the DC-DC power supply, forming the positive input terminal; the sources of the two MOSFETs in the second polarity switch group Q54 are shorted and connected to the negative terminal MINUS of the DC-DC power supply, forming the negative input terminal. The drains of the two MOSFETs in the two polarity switch groups are shorted respectively, forming the ODD output terminal and the EVEN output terminal.

[0033] The active equalization control circuit provided in this embodiment, such as Figure 6 As shown, the group number selection switch group includes two groups of group number selection switches Q58-Q59; the input terminals of the two groups of group number selection switches Q58-Q59 are respectively connected to the ODD output terminal and the EVEN output terminal, and the output terminals are respectively connected to the odd channel selection switch and the even channel selection switch in the corresponding group.

[0034] The channel selection switch and the group number selection switch are both composed of two MOSFETs connected back to back in series.

[0035] It should be noted that since battery cells have both positive and negative terminals, the number of interfaces in a battery string is one more than the number of battery cells. Therefore, the number of battery cells is N, and the number of channel selection switches is (N+1). Accordingly, after the battery cells are grouped, a single channel selection switch is shared between two adjacent battery groups and between two adjacent group number selection switches.

[0036] Based on the above-described active equalization control circuit, this embodiment also provides an active equalizer, including the above-described active equalization control circuit.

[0037] Example 2

[0038] This embodiment provides an active equalization control method based on Embodiment 1.

[0039] Based on the above-described active equalization control circuit, this embodiment also provides an active equalization control method, please refer to [link to relevant documentation]. Figure 7 This includes the following steps: S100. Encode the N battery cells in the battery string in sequence to form M battery groups.

[0040] S200: Determine the code and group of battery cells whose individual cell voltage values ​​in the battery string differ from preset values ​​by more than a preset threshold.

[0041] S300: Connect the corresponding polarity selection switch, group number selection switch group and channel selection switch according to the battery cell code and group, so that an equalization circuit is formed between the DC-DC power supply terminal and the battery cell obtained in step S200.

[0042] Please see Figure 8 Specifically, it includes: S301. If the obtained code is odd, the ODD output terminal of the first polarity switch group in the polarity selection switch is turned on, and the EVEN output terminal of the second polarity switch group is turned on. S302. If the obtained code is even, the EVEN output terminal of the first polarity switch group of the polarity selection switch is turned on, and the ODD output terminal of the second polarity switch group is turned on. S303. Select the switch group based on the obtained group number; S304. Turn on the corresponding channel selection switch according to the obtained code.

[0043] It also includes: if the obtained codes have both odd and even numbers, determining the number of odd codes and the number of even codes; If the number of odd codes is greater than the number of even codes, then step S301 is executed first, followed by step S302. If the number of even codes is greater than the number of odd codes, then step S302 is executed first, followed by step S301. In step S304, the channel selection switch corresponding to the encoding parity number needs to be turned off.

[0044] S400: Real-time detection of the individual cell voltage value of the battery cell obtained in step S200, and disconnecting the channel selection switch of the battery cell whose individual cell voltage value is less than the preset value, until the difference between the individual cell voltage value and the preset value of all battery cells is less than the preset threshold.

[0045] Example 3

[0046] This embodiment provides an active balancing control circuit applicable to 52 battery cells.

[0047] In practical applications, the mainstream number of strings in energy storage battery packs is currently 16, 48, 52, and 64. As shown in the calculation formula in the background technology, surface-mount MOSFETs can only support a maximum of 31 strings. Secondly, the unique feature of the active balancing control circuit provided in this embodiment is that it uses three layers of selection—polarity selection, group selection, and channel selection—to achieve battery balancing. Therefore, half of the battery cells within the same group will be balanced simultaneously. Thus, the maximum number of battery cells in the same group can be twice 31, i.e., 62 battery cells. Therefore, a battery pack can be composed of 1 to 62 battery cells connected in series. Conversely, a battery string is composed of multiple battery groups, and the number of battery cells depends on the number of battery groups and the number of battery cells within each battery group. Theoretically, the number of battery cells can be expanded indefinitely.

[0048] like Figure 3-4 As shown, this embodiment of the active balancing control circuit uses a battery string of 52 battery cells as an example for detailed explanation. The 52 battery cells are coded from 01 to 52. Figure 9-11 As shown, the 52 battery cells are divided into 3 battery packs, with the first two battery packs as follows: Figures 9-10 As shown, each battery pack contains 18 cells. The third battery pack is as follows: Figure 11 As shown, there are 16 battery cells.

[0049] Based on a battery string of 52 battery cells, the active balancing control circuit provided in this embodiment has 53 channel selection switches. Each of the 53 channel selection switches is connected to one of the 52 battery cells, allowing selective connection of one or more battery cells. The 53 channel selection switches are divided into three groups corresponding to the battery pack. Since a single channel selection switch is shared between two adjacent battery packs and between two adjacent group number selection switches, a single channel selection switch is also shared between the first and second battery packs, and between the second and third battery packs. It should be noted in this embodiment that... Figures 9-11 Using an abbreviated drawing method, the battery cell numbers are incremented from bottom to top, for example, in Figure 9 In the middle, the battery cells are numbered 01-18 from bottom to top. Figure 10 In the middle, the battery cells are numbered 19-36 from bottom to top. Figure 11 In the middle, the battery cells are numbered 37-52 from bottom to top, and the channel selection switch is numbered similarly. For example... Figures 9-10 As shown, battery cells coded 18 and coded 19 share the channel selection switch Q19; as Figures 10-11As shown, battery cells coded 37 and 38 share a common channel selection switch Q37, and the 53 channel selection switches correspond exactly to 52 battery cells.

[0050] Three sets of group number selection switches are connected to three sets of channel selection switches, used to selectively connect one or more sets of channel selection switches. It should be noted that although the active balancing control circuit provided in this embodiment can theoretically support a wirelessly expanded number of battery cells, the number of battery cells that can be balanced simultaneously still needs to be controlled within 31. Therefore, in the two-layer selection of group number selection switches and channel selection switches, the number of battery cells to be balanced needs to be controlled. One set of group number selection switches can simultaneously complete the balancing control of 8 or 9 battery cells, and three sets of group number selection switches can simultaneously complete the balancing control of 31 battery cells. Therefore, in this embodiment, the three sets of group number selection switches can be connected simultaneously. If the number of battery cells increases by one, becoming 53 battery cells, the three sets of group number selection switches cannot be turned on simultaneously; at least one set must be turned off.

[0051] The polarity selection switch is used to control the odd or even number of battery cells controlled in a specific group of selection switches. In terms of connection structure, the polarity selection switch includes two polarity switch groups, each consisting of two MOSFETs: the first polarity switch group Q55 and the second polarity switch group Q54. The sources of the two MOSFETs in the first polarity switch group Q55 are short-circuited and connected to the positive terminal (PLUS) of the DC-DC power supply, forming the positive input terminal. The sources of the two MOSFETs in the second polarity switch group Q54 are short-circuited and connected to the negative terminal (MINUS) of the DC-DC power supply, forming the negative input terminal. The drains of the two MOSFETs in both polarity switch groups are short-circuited, forming the ODD output terminal and the EVEN output terminal, respectively.

[0052] The group number selection switch group includes two sets of group number selection switches. The input terminals of the two sets of group number selection switches are connected to the ODD output terminal and the EVEN output terminal, respectively. The output terminals are connected to the odd-numbered channel selection switch and the even-numbered channel selection switch in the corresponding group, respectively. For example... Figure 9 As shown, for example, in the first group of group number selection switches, if the group number selection switch connected to the ODD output is connected to channel selection switches Q02, Q04, and Q06~Q18, and the group number selection switch connected to the EVEN output is connected to channel selection switches Q01, Q03, and Q05~Q19; similarly, in the second group of group number selection switches, if the group number selection switch connected to the ODD output is connected to the even-numbered channel selection switch of that group, and the group number selection switch connected to the EVEN output is connected to the odd-numbered channel selection switch. Thus, by changing the polarity of the ODD output and the EVEN output, the odd or even number of battery cells requiring balancing can be selected.

[0053] Example 4

[0054] This embodiment provides an active balancing control method based on Embodiment 3.

[0055] In the active balancing control circuit for 52 battery cells, the active balancing control method is as follows: First, the 52 battery cells in the battery string are sequentially coded and divided into three battery groups: Group 1: 01-18; Group 2: 19-36; Group 3: 37-52.

[0056] Secondly, a preset value for the battery cell voltage and a preset threshold are set; based on this, the voltage value of each individual cell in the battery string is detected; it is determined whether the difference between the detected individual cell voltage value and the preset value is greater than the preset threshold. If it is greater than the preset threshold, it is determined that the battery cell needs to be balanced, and the code and group of the battery cell are obtained.

[0057] For example, if the battery cells are coded 01, 09, and 19, they belong to the first group and the second group, respectively.

[0058] Since the number of battery cells is odd, the ODD output terminal in the first polarity switch group is turned on, and the ODD output terminal is the positive terminal of the DC-DC power supply. The EVEN output terminal in the second polarity switch group is turned on, and the EVEN output terminal is the negative terminal of the DC-DC power supply.

[0059] At this time, the output is sent to the odd channel selection switch through the group number selection switch, which corresponds to the battery cell with odd code. Since the identified battery cells are 01, 09, and 19, the first and second group number selection switches are turned on, and the channel selection switches corresponding to 01, 09, and 19 are turned on. The circuit from the DC-DC power supply to the above three battery cells is turned on, and the three battery cells are balanced.

[0060] The individual voltage values ​​of the three battery cells are detected in real time, and the channel selection switch of the battery cell whose individual voltage value is less than the preset value is disconnected until the difference between the individual voltage value of all battery cells and the preset value is less than the preset threshold.

[0061] For example, if the battery cells are coded 02, 06, and 40, they belong to the first group and the third group, respectively.

[0062] Since the number of battery cells is even, the EVEN output terminal in the first polarity switch group is turned on, and at this time the EVEN output terminal is the positive terminal of the DC-DC power supply. The ODD output terminal in the second polarity switch group is turned on, and at this time the ODD output terminal is the negative terminal of the DC-DC power supply.

[0063] At this time, the output is sent to the even-number channel selection switch through the group number selection switch, which corresponds to the battery cell with an even-number code. Since the identified battery cells are 02, 06, and 40, the first and third group number selection switches are turned on, and the channel selection switches corresponding to 02, 06, and 40 are turned on. The circuit from the DC-DC power supply to the above three battery cells is turned on, and the three battery cells are balanced.

[0064] The individual voltage values ​​of the three battery cells are detected in real time, and the channel selection switch of the battery cell whose individual voltage value is less than the preset value is disconnected until the difference between the individual voltage value of all battery cells and the preset value is less than the preset threshold.

[0065] For example, if the battery cells are coded 02, 05, and 40, they belong to the first group and the third group, respectively.

[0066] This situation involves the presence of both odd and even numbers of battery cells within the same group. Another situation is the presence of both odd and even numbers of battery cells within different groups.

[0067] In this scenario, the number of odd and even codes is first determined, and the codes with the larger number are preferentially selected for equalization control. For example, if there are 9 odd codes and 6 even codes, the odd codes are used first for equalization control. After completing the odd-number equalization control, the system switches to even-number equalization control. Furthermore, during the equalization control process, the battery cells with the corresponding codes must be disconnected. For instance, during odd-number equalization control, the channel selection switch for even-number codes must be disconnected.

[0068] The individual voltage values ​​of the three battery cells are detected in real time, and the channel selection switch of the battery cell whose individual voltage value is less than the preset value is disconnected until the difference between the individual voltage value of all battery cells and the preset value is less than the preset threshold.

[0069] In summary, the active balancing control circuit and method provided in Examples 1-11, by sequentially connecting the polarity selection switch, the group number selection switch group, and the channel selection switch, connects at least one or more battery cells in a battery pack to form a balancing loop. In the circuit connection structure, the number of battery cells that can be supported is theoretically unlimited, as long as the number of battery cells that can be balanced simultaneously after three layers of selection is within 31. Therefore, it can meet the current mainstream string counts of energy storage battery packs: 16 strings, 48 ​​strings, 52 strings, and 64 strings, and can better meet the development requirements of battery packs with more strings.

[0070] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An active equalization control circuit, characterized in that: Balanced control of a battery string consisting of N battery cells connected in series, wherein the battery string is divided into M battery groups; Where N and M are positive integers greater than 2; including: (N+1) channel selection switches are connected to N battery cells in the battery string, and are divided into M groups of channel selection switches corresponding to the battery pack, for selectively connecting one or more of the battery cells; M group number selection switch group, which is connected to M group channel selection switch group, is used to selectively access one or more of the channel selection switch groups; A polarity selection switch, one side of which is connected to the DC-DC power supply terminal and the other side of which is connected to the group number selection switch group, is used to selectively connect to the odd-numbered channel selection switch or the even-numbered channel selection switch; The active balancing control circuit connects the polarity selection switch, the group number selection switch group, and the channel selection switch in sequence to enable at least one or more battery cells in a group of battery packs to form a balancing loop. A single channel selection switch is shared between two adjacent battery packs and between two adjacent group number selection switches. The polarity selection switch includes two polarity switch groups composed of two MOSFETs, namely the first polarity switch group and the second polarity switch group. The sources of the two MOSFETs in the first polarity switch group are shorted and connected to the positive terminal of the DC-DC power supply to form the positive input terminal; the sources of the two MOSFETs in the second polarity switch group are shorted and connected to the negative terminal of the DC-DC power supply to form the negative input terminal. The drains of the two MOSFETs in the two polarity switch groups are shorted to form the ODD output terminal and the EVEN output terminal respectively; The group number selection switch group includes two groups of group number selection switches; the input terminals of the two groups of selection switches are respectively connected to the ODD output terminal and the EVEN output terminal, and the output terminals are respectively connected to the odd-numbered channel selection switch and the even-numbered channel selection switch in the corresponding group; Each battery pack contains no more than 31 battery cells.

2. The active equalization control circuit according to claim 1, characterized in that: The selection switches for the channel selection switch and the group number selection switch include: two MOS transistors connected in series back to back.

3. An active equalization control method based on the active equalization control circuit according to any one of claims 1-2, characterized in that: Includes the following steps: S100. Encode the N battery cells in the battery string in sequence to form M battery groups; S200: Determine the code and group of the battery cell whose difference between the individual cell voltage value and the preset value in the battery string is greater than a preset threshold; S300: Connect the corresponding polarity selection switch, group number selection switch group and channel selection switch according to the battery cell code and group, so that the DC-DC power supply terminal and the battery cell obtained in step S200 form an equalization circuit. S400: Real-time detection of the individual cell voltage value of the battery cell obtained in step S200, and disconnecting the channel selection switch of the battery cell whose individual cell voltage value is less than the preset value, until the difference between the individual cell voltage value and the preset value of all battery cells is less than the preset threshold.

4. The active balancing control method according to claim 3, characterized in that: In step S300, the corresponding polarity selection switch, group number selection switch group, and channel selection switch are connected according to the battery cell's code and group; including: S301. If the obtained code is odd, the ODD output terminal of the first polarity switch group in the polarity selection switch is turned on, and the EVEN output terminal of the second polarity switch group is turned on. S302. If the obtained code is even, the EVEN output terminal of the first polarity switch group of the polarity selection switch is turned on, and the ODD output terminal of the second polarity switch group is turned on. S303. Select the switch group based on the obtained group number; S304. Turn on the corresponding channel selection switch according to the obtained code.

5. The active equalization control method according to claim 4, characterized in that: In step S300, if the obtained codes have both odd and even numbers, the number of odd codes and the number of even codes are determined. If the number of odd codes is greater than the number of even codes, then step S301 is executed first, followed by step S302. If the number of even codes is greater than the number of odd codes, then step S302 is executed first, followed by step S301. In step S304, the channel selection switch corresponding to the encoding parity number is turned off.

6. An active equalizer, characterized in that: The active equalization control circuit includes any one of claims 1-2.

Images