Battery assembly, electronic device, and battery equalization method

Abstract

The application provides a battery assembly, an electronic device and a battery equalization method, and belongs to the technical field of electronics. The battery assembly comprises a battery module and a control module. The battery module comprises a primary discharge path and a plurality of series-connected battery cells. Every n series-connected battery cells form a battery cell group. The two poles of each battery cell are connected through a primary discharge path. The primary discharge path comprises a first switch module and a first load connected with the first switch module. The first switch module is used for conducting the primary discharge path and the battery cell in a closed state to form a discharge loop of the battery cell. The control module is used for controlling the first switch module in a target discharge path to be closed in the case that a battery cell group is determined to be a target battery cell group that needs to be equalized according to the charge amount and the voltage of the single battery cell group in a charging process. The target discharge path is a primary discharge path connected with a battery cell that needs to be discharged in the target battery cell group. The application effectively reduces the voltage sampling cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronics, and in particular to a battery assembly, an electronic device, and a battery equalization method. BACKGROUND

[0002] At present, the power supply part of an electronic device is usually a battery pack composed of multiple series-connected battery cells, which is used to provide a larger continuous power supply current. However, due to problems such as battery cell manufacturing process and use conditions, there are performance differences between different battery cells in the battery pack, which causes differences in voltage and capacity between the battery cells during use, affecting the performance of the battery pack. Battery equalization technology can keep the single-cell voltage / capacity deviation of each battery cell in the battery pack within an expected range and maintain the consistency of the battery cells by actively transferring the energy of the battery cells (such as active equalization) or consuming the excess energy of the battery cells (such as passive equalization).

[0003] At present, the battery equalization technology usually collects the single-cell voltage of each battery cell in the battery pack to determine the battery cell that needs to be equalized, so as to transfer or consume the energy of the battery cell, thereby achieving battery equalization. However, the method of collecting the single-cell voltage of each battery cell obviously has the problem of high voltage sampling cost. SUMMARY

[0004] The embodiments of the present application provide a battery assembly, an electronic device, and a battery equalization method, which can effectively solve the problem of high voltage sampling cost in the current battery equalization process.

[0005] In a first aspect, the embodiments of the present application provide a battery assembly, which comprises a battery module and a control module.

[0006] The battery module comprises a primary discharge path and multiple series-connected battery cells. Every n series-connected battery cells form a battery cell group. The two poles of each battery cell are connected through a primary discharge path. The primary discharge path comprises a first switch module and a first load connected to the first switch module. The first switch module is used to turn on the primary discharge path and the battery cell when closed, thereby forming a discharge loop of the battery cell.

[0007] The control module is connected to the two poles of each battery cell group and the first switch module. When it is determined that a single battery cell group needs to be equalized according to the charge amount and voltage of the battery cell group during charging, the control module controls the first switch module in the target discharge path to be closed. The target discharge path is the primary discharge path connected to the battery cell that needs to be discharged in the target battery cell group.

[0008] Optionally, the control module is further configured to determine the target battery cell group as the target battery cell group according to the variation of the charge amount and the voltage of each of the battery cell groups in the charging process.

[0009] Optionally, the control module is further configured to determine the target battery cell group as the target battery cell group according to the variation of the charge amount and the voltage of each of the battery cell groups in the charging process.

[0010] Optionally, the control module is further configured to determine the target battery cell group as the target battery cell group according to the variation of the charge amount and the voltage of each of the battery cell groups in the charging process.

[0011] Optionally, the control module is further configured to determine the target battery cell group as the target battery cell group according to the variation of the charge amount and the voltage of each of the battery cell groups in the charging process.

[0012] Optionally, the control module is further configured to determine the target battery cell group as the target battery cell group according to the variation of the charge amount and the voltage of each of the battery cell groups in the charging process.

[0013] Optionally, the control module is further configured to determine the target battery cell group as the target battery cell group according to the variation of the charge amount and the voltage of each of the battery cell groups in the charging process.

[0014] Optionally, the control module is further configured to determine the target battery cell group as the target battery cell group according to the variation of the charge amount and the voltage of each of the battery cell groups in the charging process.

[0015] Optionally, n=2; the control module is further configured to control the first switch module in the first discharge path to be closed in a case that a decrease between two peak values of a target state value of the target battery cell group is determined according to a charge amount and a voltage of the target battery cell group in a recharging process.

[0016] Optionally, the control module is further configured to control the first switch module in the target discharge path to be closed for a target equalization duration, wherein the target equalization duration is in direct proportion to a second interval, the second interval being an interval between the two peak values of the target state value determined according to the charge amount and the voltage of the target battery cell group in the recharging process.

[0017] Optionally, the target equalization duration is determined according to the second interval and a resistance value of the first load.

[0018] Optionally, the target equalization duration is a ratio of the second interval and the resistance value of the first load.

[0019] Optionally, the control module is further configured to determine a single battery cell group as a target battery cell group requiring equalization according to a variation feature of a charge amount and a voltage of the single battery cell group in a charging process in a case that a charging current of the battery module in the charging process is less than or equal to a target current, and a variation history of a battery charge state of the battery module includes at least a target state range, wherein the target current and the target state range are related to an existence condition of a charging inflection point of the battery module.

[0020] Optionally, n=2, the battery cell group includes a first battery cell and a second battery cell; two first discharge paths connected to the same battery cell group share one first load.

[0021] Optionally, the battery module further includes: a second discharge path, two poles of each battery cell group being connected through one second discharge path, the second discharge path including a second switch module and a second load connected to the second switch module, the second switch module being configured to conduct the second discharge path and the battery cell group to form a discharge loop of the battery cell group when the second switch module is closed.

[0022] The control module is further connected to the second switch module and configured to control the second switch module to be closed or opened according to a voltage and a charge amount of each battery cell group in a charging process.

[0023] Optionally, the control module is further configured to perform battery equalization processing on the battery module according to the voltage and the charge amount of each of the battery groups during charging, to obtain an equalization processing result, and to control the second switch module in the secondary discharge path to which each of the battery groups is connected to be closed or opened according to the equalization processing result, the equalization processing result at least indicating whether each of the battery groups needs to be discharged.

[0024] Optionally, the two secondary discharge paths of the two battery groups connected in series share one second load.

[0025] In a second aspect, an embodiment of the present application provides an electronic device, which comprises the battery assembly of any of the first aspect.

[0026] In a third aspect, an embodiment of the present application provides a battery equalization method, which is applied to the battery assembly of any of the first aspect or the electronic device of the second aspect, and the method comprises:

[0027] In a case where it is determined that the battery group is a target battery group that needs to be equalized according to the charge amount and the voltage of the battery group during charging, the first switch module in the target discharge path is controlled to be closed, wherein the target discharge path is the primary discharge path to which the battery that needs to be discharged in the target battery group is connected.

[0028] The present application has the following advantages:

[0029] The battery assembly provided by the embodiment of the present application comprises a battery module and a control module. The battery module comprises a primary discharge path and a plurality of series-connected battery cells. Two poles of each battery cell are connected through one primary discharge path, and the primary discharge path comprises a first switch module and a first load connected to the first switch module. Every n series-connected battery cells in the battery module form one battery group. The control module is connected to two poles of each battery group and the first switch module, and is configured to, in a case where it is determined that the battery group is a target battery group that needs to be equalized according to the charge amount and the voltage of the battery group during charging, control the first switch module in the primary discharge path to which the battery that needs to be discharged in the target battery group is connected to be closed, so as to turn on the primary discharge path connected to the battery that needs to be discharged, form a discharge loop of the battery, discharge the battery, and realize battery equalization of the battery group.

[0030] In the technical solution, the control module can collect the voltage and the charge amount of at least one battery group composed of n series-connected battery cells, to determine whether the battery group needs to be equalized, so as to realize battery equalization of the battery group. Therefore, compared with the manner in the related art that needs to collect the voltage of each battery cell to realize battery equalization, the present application can effectively reduce the voltage sampling cost in the battery equalization process and improve the voltage sampling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments.

[0032] Figure 1 One of the structural schematic diagrams of the battery assembly provided in an embodiment of the present application;

[0033] Figure 2 The second structural diagram of the battery assembly provided in the embodiment of the present application;

[0034] Figure 3 This is one of the curve diagrams showing the change of voltage with charge provided in the embodiment of the present application;

[0035] Figure 4 The second schematic diagram of the curve showing the change of voltage with charge provided in the embodiment of the present application;

[0036] Figure 5 The third schematic diagram of the curve showing the change of voltage with charge provided in the embodiment of the present application;

[0037] Figure 6 The fourth schematic diagram of the curve showing the change of voltage with charge provided in the embodiment of the present application;

[0038] Figure 7 This is one of the schematic diagrams of the change curve of the target state value provided in the embodiment of the present application;

[0039] Figure 8 The second schematic diagram of the change curve of the target state value provided in the embodiment of the present application;

[0040] Figure 9 The third schematic diagram of the change curve of the target state value provided in the embodiment of the present application;

[0041] Figure 10 The fourth schematic diagram of the change curve of the target state value provided in the embodiment of the present application;

[0042] Figure 11 The fifth diagram of the change curve of the target state value provided in the embodiment of the present application;

[0043] Figure 12 This is one of the flow charts of the battery balancing method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0045] Reference will now be made to Figure 1 , which shows a structural schematic diagram of a battery assembly provided by an embodiment of the present application. As shown in Figure 1 , the battery assembly comprises a battery module 1 and a control module (not shown). Figure 1

[0046] The battery module 1 comprises a primary discharge path 11 and a plurality of series-connected battery cells. Every n series-connected battery cells form a battery cell group 12. Two poles of each battery cell are connected by a primary discharge path 11. The primary discharge path comprises a first switch module and a first load connected to the first switch module. The first switch module is used to close the primary discharge path 11 and the battery cell to form a discharge loop of the battery cell when closed. The discharge loop of the battery cell is used to discharge the battery cell to achieve battery balancing of the battery module 1.

[0047] The control module is connected to two poles of each battery cell group 12 and the first switch module. The control module is used to control the first switch module in the target discharge path to be closed when it is determined that the battery cell group 12 is a target battery cell group that needs to be balanced according to the charge amount and voltage of the individual battery cell group 12 during charging.

[0048] wherein n is a positive integer greater than 2. The first switch module connected to each battery cell of the battery module 1 is open during charging to disconnect the battery cell from the primary discharge path 11 connected to the battery cell, thereby ensuring effective charging of the battery cell. The target battery cell group that needs to be balanced refers to a battery cell group in which there is a difference between the battery cells. The difference between the battery cells can refer to inconsistent individual voltages or inconsistent charge amounts of the battery cells. The target discharge path is a primary discharge path connected to the battery cell that needs to be discharged in the target battery cell group. The battery cell that needs to be discharged refers to a battery cell with relatively large battery energy (e.g., individual voltage, charge amount) in the battery cell group.

[0049] It should be noted that the first load can be a resistor, an inductive load, etc. Figure 1 Taking n as 2, the battery module 1 comprises eight battery cells B1-B8, and taking a resistor as an example of the first load. Accordingly, in order to better identify the first switch module and the first load in the primary discharge path 11 connected to different battery cells, Figure 1 ​The first switch module K1_1-K1_8 and the first load R1_1-R1_8 in the first discharge path corresponding to the eight battery cells B1-B8 are respectively marked.

[0050] In an alternative case, one pole of a single battery cell is connected to one end of a first switch module in the first discharge path 11, and the other end of the first switch module is connected to the other pole of the battery cell through a first load. Correspondingly, the control module can be used to directly control the first switch module in the target discharge path to be closed, and control the first switch modules in the first discharge paths connected by the target battery cell group 12 except the target discharge path to be opened, in the case that the target battery cell group is determined to be a target battery cell group requiring balancing according to the charge amount and voltage of the single battery cell group 12 in the charging process.

[0051] Alternatively, as shown in Figure 2 , n is 2, and the battery cell group 12 includes a first battery cell and a second battery cell. The two first discharge paths 11 connected by the same battery cell group 12 share a first load. That is, in the same battery cell group 12, the first load in the first discharge path 11 connected by the first battery cell and the first load in the first discharge path 11 connected by the second battery cell are the same. As shown in Figure 2 , taking the battery cell group 12 composed of the first battery cell B1 and the second battery cell B2 as an example. In this battery cell group 12, one end of the first battery cell B1 is connected to the other end of the first battery cell B1 through the first switch module K1_1 and the first load R1_1 in sequence. And one end of the second battery cell B2 (i.e. the common connection end of the second battery cell B2 and the first battery cell B1) is connected to the other end of the second battery cell B2 through the first load R1_1 and the first switch module K1_2 in sequence.

[0052] Correspondingly, within a single battery cell group 12, if the first battery cell needs to be discharged to achieve battery balancing, the control module can control the first switch module of the first discharge path 11 connected by the first battery cell to be closed, and control the first switch module of the first discharge path 11 connected by the second battery cell to be opened. Similarly, if the second battery cell needs to be discharged to achieve battery balancing, the control module can control the first switch module of the first discharge path 11 connected by the second battery cell to be closed, and control the first switch module of the first discharge path 11 connected by the first battery cell to be opened. It should be noted that in a single battery cell group 12, the two first switch modules connected by the first battery cell and the second battery cell cannot be closed at the same time to avoid causing the battery cell group 12 to be short-circuited.

[0053] It should be noted that, Figure 2 Taking the battery module 1 including eight battery cells B1-B8 and the first load being a resistor as an example. Correspondingly, in order to better identify the first switch module and the first load in the first discharge path 11 connected by different battery cells, Figure 2In the figure, the first switch modules K1_1 - K1_8 and the first loads R1_1 - R1_4 respectively identify the first switch modules and the first loads in the primary discharge path 11 to which the eight battery cells B1 - B8 are connected.

[0054] Specifically, for example, Figure 2 As shown, n is 2. Battery module 1 includes eight primary discharge paths 11 and eight series-connected cells B1-B8. The eight series-connected cells B1-B8 include four cell groups 12: cell group (B1, B2) 12, cell group (B3, B4) 12, cell group (B5, B6) 12, and cell group (B7, B8) 12. Cell group (Bi, Bj) represents a cell group that includes cells Bi and Bj. Furthermore, the primary discharge path 11 connecting the two electrodes of cell B1 includes a first switch module K1_1 and a first load R1_1. The primary discharge path 11 connecting the two electrodes of cell B2 includes a first switch module K1_2 and a reused first load R1_1, and so on. The primary discharge path 11 connecting the two electrodes of cell B7 includes a first switch module K1_7 and a first load R1_4. The primary discharge path 11 connecting the two electrodes of the battery cell B8 includes a first switch module K1_8 and a multiplexed first load R1_4.

[0055] The control module is connected to the two poles of cell groups (B1, B2), (B3, B4), (B5, B6), and (B7, B8), and is also connected to the first switch modules K1_1-K1_8. The control module is used to collect the charge and voltage of each cell group 12 during charging of battery module 1 and, based on the charge and voltage of each cell group 12 during charging, determine whether the cell group 12 is a target cell group requiring balancing. Furthermore, the control module is used to control the first switch module in the target discharge path to be closed, and the first switch modules in other discharge paths to remain open, when the cell group 12 is determined to be the target cell group that needs to be balanced based on the charge and voltage of the cell group 12, so that the target cell in the target cell group (i.e., the cell that needs to be discharged) is connected to its primary discharge path, forming a discharge circuit for the target cell, discharging the target cell, and achieving battery balancing for each cell in the cell group 12, that is, achieving intra-group battery balancing of the cell group 12. Among them, the target discharge path is the primary discharge path connected to the cell that needs to be discharged in the target cell group. The other discharge paths are the primary discharge paths other than the target discharge path among the n primary discharge paths connected to the n cells included in the target cell group.

[0056] In the embodiment of the present application, the control module is used to control the first switch module in the target discharge path to close when the cell group 12 is determined to be the target cell group that needs to be balanced based on the charge and voltage of the single cell group 12 during charging.

[0057] Specifically, when the cells in the cell group 12 are in a balanced state, the first and second variation characteristics of the charge and voltage of a single cell group 12 during the charging process of the battery module 1 are different. The second variation characteristic refers to the variation characteristics of the charge and voltage of the cell group 12 during the charging process when the cells in the single cell group 12 are in an unbalanced state.

[0058] For example, assume that a single battery cell group 12 includes two battery cells connected in series. Figures 3 to 6 . Figure 3 1 shows a curve showing a change in the single cell voltage V of the two cells in a single cell group 12 as a function of the charge Q during the charging process of the battery module 1 when the two cells in the cell group 12 are in a balanced state. Figure 4 1 shows a curve showing a change in voltage V of a single cell group 12 versus charge Q during charging of the battery module 1 when two cells in the cell group 12 are in a balanced state. Figure 5 The graph shows a curve showing a change in the single cell voltage V of two cells in a single cell group 12 as a function of the charge Q during the charging process of the battery module 1 when the two cells in the cell group 12 are in an unbalanced state. Figure 6 1 shows a curve showing a change in voltage V of a single cell group 12 versus charge Q during charging of the battery module 1 when two cells in the cell group 12 are in an unbalanced state.

[0059] Depend on Figure 4 and Figure 6 It can be clearly seen that the curve of the voltage V of a single cell group 12 changing with the charge Q when the cells in the cell group 12 are in a balanced state is different from the curve of the voltage V of a single cell group 12 changing with the charge Q when the cells in the cell group 12 are in an unbalanced state. Therefore, when the cells in the cell group 12 are in a balanced state, the first change characteristics of the charge and voltage of the single cell group 12 are different from the second change characteristics of the charge and voltage of the single cell group 12 when the cells in the cell group 12 are in an unbalanced state.

[0060] Based on this, the control module can be optionally used to collect the charge and voltage of each battery cell group 12 of the battery module 1 during the charging process. For each battery cell group 12, based on the change characteristics of the charge and voltage of the single battery cell group 12 during the charging process, it is determined whether the battery cell group 12 is the target battery cell group that needs to be balanced, so as to control the first switch module in the target discharge path to be closed when it is determined that the battery cell group 12 is the target battery cell group that needs to be balanced based on the change characteristics of the charge and voltage of the single battery cell group 12 during the charging process.

[0061] For example, a curve showing a change in voltage versus charge can reflect the changing characteristics of charge and voltage. The control module can be configured to plot a curve showing a change in voltage versus charge for each cell group 12, calculate the similarity between the change curve and a reference curve, and determine whether the change characteristics of charge and voltage during the charging process reflected by the change curve are similar to the similarity between the change curve and the reference curve. The reference curve is a curve showing a change in voltage versus charge for the cell group 12 when the cells in the cell group 12 are in an unbalanced state.

[0062] If the similarity is greater than or equal to the similarity threshold, indicating that the change characteristics of the charge and voltage during the charging process reflected by the change curve are consistent with the change characteristics of the charge and voltage during the charging process reflected by the reference curve, the battery cell group 12 is determined to be the target battery cell group that needs to be balanced, and the first switch module in the target discharge path is controlled to be closed, while the first switch modules in other discharge paths remain open. If the similarity is less than the similarity threshold, indicating that the change characteristics of the charge and voltage during the charging process reflected by the change curve are inconsistent with the change characteristics of the charge and voltage during the charging process reflected by the reference curve, the battery cell group 12 is determined not to be the target battery cell group that needs to be balanced, and the first switch modules connecting the battery cells in the target battery cell group can be controlled to remain open.

[0063] It should be noted that the battery cell has a charging inflection point. The charging inflection point refers to the point where the voltage or current characteristics of a single cell change significantly during the charging process of the battery cell. Figure 3 As shown, when the cells in the cell group 12 are in a balanced state, each cell in a single cell group 12 has an obvious charging inflection point. Figure 5 As shown, when the cells in the cell group 12 are in an unbalanced state, each cell in a single cell group 12 has more charging inflection points. Figure 4 As shown, when the cells in the cell group 12 are in a balanced state, a single cell group 12 also has an obvious charging inflection point. Figure 6As shown, when each cell in the cell group 12 is in the non-equilibrium state, the single cell group 12 has more charging inflection points. Obviously, in the case that the cell group 12 experiences the charging process in which the charging inflection point is located, the curve of the voltage change with the charge amount when each cell in the cell group 12 is in the equilibrium state has a larger change compared with the curve of the voltage change with the charge amount when each cell in the cell group 12 is in the non-equilibrium state.

[0064] Based on this, the control module can be used to determine, in the case that the battery module 1 experiences the charging process in which the charging inflection point is located, for each cell group 12, whether the cell group 12 is a target cell group that needs to be balanced according to the change characteristics of the charge amount and the voltage of the single cell group 12 in the charging process, which can effectively utilize the larger difference between the change characteristics of the voltage and the charge amount of the single cell group 12 in the equilibrium state and the non-equilibrium state in the charging process in which the charging inflection point is located, improve the judgment accuracy of the target cell group, and thus effectively improve the battery balancing efficiency.

[0065] In some embodiments, for different specifications of batteries, if the battery needs to have a clear charging inflection point in the charging process, the battery has certain requirements for the charging current and at least the battery state of charge (SOC) that needs to be experienced. For example, for a lithium iron phosphate battery, the charging current is within 0.3C, and the change process of the SOC in the charging process includes 50%-70%, the lithium iron phosphate battery has a clear charging inflection point in the charging process. Among them, the change process of the SOC in the charging process includes 50%-70% means that the battery starts to charge continuously from SOC below 50% to SOC above 70%.

[0066] Correspondingly, the control module is also used to determine, in the case that the charging current of the battery module 1 in the charging process is less than or equal to the target current, and the change process of the battery state of charge of the battery module 1 includes at least the target state range, the cell group as a target cell group that needs to be balanced according to the change characteristics of the charge amount and the voltage of the single cell group in the charging process. Among them, the values of the target current and the target state range are related to the existence condition of the charging inflection point of the battery module 1. For example, in the case that the cell is a lithium iron phosphate battery, the target current is within 0.3C; the target state range is [40, 80].

[0067] For example, the control module is further configured to acquire the charging current and the SOC of the battery module 1 during the charging process, determine whether the charging current is greater than the target current, and determine whether the variation of the battery state of charge includes the target state range in the case that the charging current is greater than the target current. Thus, in the case that the variation of the battery state of charge of the battery module 1 includes the target state range, the single cell group is determined as the target cell group according to the variation of the charge amount and the voltage of the single cell group during the charging process.

[0068] In the embodiments of the present application, it is assumed that the single cell group 12 includes two cells connected in series. Please refer to Figures 7 to 10 . Figure 7 The figure shows the variation curve of the target state value of the two cells of the single cell group 12 with the charge amount Q during the charging process of the battery module 1 when the two cells in the cell group 12 are in the balanced state. The target state value refers to the instantaneous change rate of the voltage with the charge amount, i.e., the ratio dV / dQ between the change amount of the charge and the change amount of the voltage of the cell. Figure 8 The figure shows the variation curve of the target state value dV / dQ of the single cell group 12 with the charge amount Q during the charging process of the battery module 1 when the two cells in the cell group 12 are in the balanced state. Figure 9 The figure shows the variation curve of the target state value dV / dQ of the two cells of the single cell group 12 with the charge amount Q during the charging process of the battery module 1 when the two cells in the cell group 12 are in the unbalanced state. Figure 10 The figure shows the variation curve of the target state value dV / dQ of the single cell group 12 with the charge amount Q during the charging process of the battery module 1 when the two cells in the cell group 12 are in the unbalanced state.

[0069] From Figure 8 and Figure 10 It can be obviously seen that the target state value dV / dQ of the single cell group 12 has one peak (i.e., maximum value) when the two cells in the cell group 12 are in the balanced state. The target state value dV / dQ of the single cell group 12 has two peaks (i.e., maximum values) when the two cells in the cell group 12 are in the unbalanced state. Obviously, the number of peaks of the target state value dV / dQ of the cell group 12 is different when the cell group 12 is in the balanced state and the unbalanced state.

[0070] Based on this, the control module can be further configured to determine the cell group 12 as the target cell group in the case that the target state value dV / dQ of the cell group 12 has at least two peaks according to the charge amount and the voltage of the single cell group 12. Correspondingly, the control module can be configured to determine the cell group 12 as not the target cell group in the case that the target state value dV / dQ of the cell group 12 has one peak according to the charge amount and the voltage of the single cell group 12.

[0071] Since the number of peaks of the target state value dV / dQ of the battery cell group 12 in the charging process is easier to determine, and the number of peaks of the target state value dV / dQ can more simply and clearly reflect whether the battery cell group 12 is in the balanced state. Therefore, the control module determines whether the battery cell group 12 is in the balanced state according to whether the number of peaks of the target state value dV / dQ of the battery cell group 12 is greater than 1, so as to determine the battery cell group 12 as the target battery cell group which needs to be balanced in the case that the battery cell group 12 is determined to be in the unbalanced state, which can effectively improve the judgment efficiency and accuracy of whether the battery cell group 12 is balanced.

[0072] Further optionally, the control module can obtain the target state value of the single battery cell group 12 by calculating the derivative value of the voltage to the charge amount of the battery cell group 12. Based on this, the control module can also be used to determine the single battery cell group 12 as the target battery cell group according to the derivative value of the voltage to the charge amount of each battery cell group 12 (i.e. the target state value) in the case that the derivative value of the single battery cell group 12 in the charging process has at least two peaks.

[0073] For example, the control module can also be used to collect the charge amount and voltage of each battery cell group 12 of the battery module 1 in the charging process, and the charging current and SOC of the battery module 1 in the charging process. Determine whether the charging current is greater than the target current, and whether the change process of the battery charge state includes at least the target state range. Thus, in the case that the charging current is less than or equal to the target current, and the change process of the battery charge state includes at least the target state range, the control module calculates the derivative value of the voltage to the charge amount of each battery cell group 12; determines whether the derivative value of the single battery cell group 12 in the charging process has at least two peaks to determine whether the battery cell group 12 is balanced.

[0074] In the case that the derivative value of the battery cell group 12 in the charging process has at least two peaks, indicating that the battery cell group 12 is in the unbalanced state, the control module determines the battery cell group 12 as the target battery cell group and controls the first switch module in the target discharge path to be closed. In the case that the derivative value of the battery cell group 12 in the charging process does not have at least two peaks, indicating that the battery cell group 12 is in the balanced state, the control module determines that the battery cell group 12 is not the target battery cell group and does not control the first switch module in the target discharge path to be closed.

[0075] In the embodiments of the present application, the battery assembly comprises a battery module and a control module. The battery module comprises a primary discharge path and a plurality of series-connected battery cells. Two poles of each battery cell are connected by a primary discharge path, and the primary discharge path comprises a first switch module and a first load connected to the first switch module. Every n series-connected battery cells in the battery module form a battery cell group. The control module is connected to two poles of each battery cell group and the first switch module, and is configured to, in a case where it is determined according to the charge amount and voltage of a single battery cell group during charging that the battery cell group is a target battery cell group that needs to be balanced, control the first switch module in the primary discharge path connected to the battery cell that needs to be discharged in the target battery cell group to be closed, so as to turn on the primary discharge path connected to the battery cell that needs to be discharged, form a discharge loop of the battery cell, discharge the battery cell, and achieve battery balancing of the battery cell group.

[0076] In the technical solution, the control module can collect the voltage and charge amount of at least one battery cell group composed of n series-connected battery cells, to determine whether the battery cell group needs to be balanced, thereby achieving battery balancing of the battery cell group. Therefore, compared with the related art which needs to collect the voltage of each battery cell to achieve battery balancing, the present application can effectively reduce the voltage sampling cost in the battery balancing process and improve the voltage sampling efficiency.

[0077] In some embodiments of the present application, the control module is further configured to, in a case where it is determined according to the charge amount and voltage of a single battery cell group 12 during charging that the battery cell group 12 is a target battery cell group that needs to be balanced, control the first switch module in the first discharge path connected to the target battery cell group to be closed for a target duration, and control the first switch module in the second discharge path connected to the target battery cell group to be disconnected, and determine the change trend of the difference between the battery cells in the target battery cell group according to the charge amount and voltage of the target battery cell group during recharging, and control the first switch module in the target discharge path according to the change trend.

[0078] The n first discharge paths connected to the target battery cell group are composed of a first discharge path and a second discharge path. The first discharge path is a first discharge path connected to any battery cell in the target battery cell group. The change trend of the battery cell difference refers to an increase or decrease of the battery cell difference between each battery cell in the target battery cell group. Optionally, the control module is further configured to, in a case where it is determined that the battery cell group 12 is the target battery cell group requiring balancing according to the charge amount and the voltage of the battery cell group 12 in the charging process, control the first switch module in the first discharge path connected to the target battery cell group to be closed for a target time length, and control the first switch module in the second discharge path connected to the target battery cell group to be disconnected, so that the battery cell connected to the first discharge path is discharged for the target time length. Then, after the battery module 1 is charged next time, the change trend of the battery cell difference in the target battery cell group is determined according to the charge amount and the voltage of the target battery cell group in the charging process again, so as to determine whether the first switch module in the first discharge path is closed according to the change trend, so that it is determined whether the discharge of the battery cell connected to the first discharge path achieves the balancing effect. Thus, according to the change trend of the battery cell difference in the target battery cell group, the battery cell requiring discharge in the target battery cell group is determined, the first switch module in the target discharge path connected to the battery cell is controlled to be closed, so as to discharge the battery cell requiring discharge in the target battery cell group, and the balancing in the target battery cell group is achieved.

[0079] Optionally, the control module is further configured to, in a case where it is determined that the battery cell difference in the target battery cell group increases according to the charge amount and the voltage of the target battery cell group in the charging process again, adjust the on-off state of the first discharge path and the second discharge path connected to the target battery cell group. Further optionally, the control module is further configured to, in a case where it is determined that the battery cell difference in the target battery cell group decreases according to the charge amount and the voltage of the target battery cell group in the charging process again, control the first switch module in the target discharge path to be closed. The target discharge path is the first discharge path in which the first switch module was closed last time by the control module. That is, the target discharge path is the first discharge path in which the first switch module was closed last time, and the battery cell connected to the target discharge path is the battery cell discharged last time.

[0080] In a case where it is determined that the battery cell difference in the target battery cell group increases according to the charge amount and the voltage of the target battery cell group in the charging process again, it indicates that the battery cell discharged last time is the battery cell with relatively low energy in the target battery cell group, and the discharge of the battery cell aggravates the battery cell difference between each battery cell in the target battery cell group. In a case where it is determined that the battery cell difference in the target battery cell group decreases according to the charge amount and the voltage of the target battery cell group in the charging process again, it indicates that the battery cell discharged last time is the battery cell with relatively high energy in the target battery cell group, that is, the battery cell discharged last time is the battery cell requiring discharge in the target battery cell group, and the discharge of the battery cell reduces the battery cell difference between each battery cell in the target battery cell group,

[0081] Based on this, optionally, in the case of n being 2, the two primary discharge paths connected by the target battery cell group are composed of the first discharge path and the second discharge path. If the control module determines that the difference between the battery cells in the target battery cell group increases according to the charge amount and voltage of the target battery cell group in the recharging process, it can be indicated that the energy of the battery cell connected by the first discharge path is lower than that of the battery cell connected by the second discharge path, and discharging the battery cell connected by the first discharge path aggravates the battery imbalance in the target battery cell group, while the battery cell connected by the second discharge path is the battery cell that needs to be discharged in the target battery cell group. Based on this, the control module can be used to directly control the first switch module in the second discharge path to be closed and control the first switch module in the first discharge path to remain closed in the case where the difference between the battery cells in the target battery cell group increases according to the charge amount and voltage of the target battery cell group in the recharging process, so as to effectively realize the discharge of the battery cell with higher energy in the target battery cell group through the primary discharge path and achieve the battery balancing in the target battery cell group.

[0082] In the case where n is greater than 2, the number of primary discharge paths connected by the target battery cell group is greater than 2. The number of first discharge paths can be at least one, and accordingly the number of second discharge paths is adjusted according to the number of first discharge paths, which can also be at least one.

[0083] If the control module determines that the difference between the battery cells in the target battery cell group increases according to the charge amount and voltage of the target battery cell group in the recharging process, it can be indicated that discharging the battery cell connected by at least one first discharge path aggravates the battery balancing in the target battery cell group. However, it cannot be determined at the same time that discharging the battery cell connected by the second discharge path can achieve the battery balancing in the battery cell group.

[0084] Therefore, the control module can be used to adjust the on-off state of the first discharge path and the second discharge path connected by the target battery cell group, i.e., adjust the on-off state of the first switch module in the first discharge path and the second discharge path connected by the target battery cell group, in the case where the difference between the battery cells in the target battery cell group increases according to the charge amount and voltage of the target battery cell group in the recharging process. Thus, after the next charging of the battery module 1, the change trend of the difference between the battery cells in the target battery cell group is determined according to the charge amount and voltage of the target battery cell group in the charging process, so as to adjust the on-off state of the first discharge path and the second discharge path connected by the target battery cell group again in the case where the change trend is that the difference between the battery cells increases. In this way, the change trend of the difference between the battery cells in the target battery cell group is determined until the change trend is that the difference between the battery cells decreases, the first switch module in the target discharge path is controlled to be closed, so as to make the battery cell discharged in the previous time continue to be discharged, and achieve the battery balancing in the target battery cell group.

[0085] In some embodiments, the control module is further configured to, when it is determined based on the charge and voltage of the target cell group during the recharging process that the target state value of the target cell group has an increasing distance between at least two peaks, determine that the trend of change in the difference between the cells in the target cell group is increasing, and adjust the on / off state of the first discharge path and the second discharge path. Further optionally, the control module is further configured to, when it is determined based on the charge and voltage of the target cell group during the recharging process that the target state value of the target cell group has a decreasing distance between at least two peaks, determine that the trend of change in the difference between the cells in the target cell group is decreasing, and control the first switch module in the target discharge path to close, where the target discharge path is the primary discharge path for which the control module previously controlled the first switch module to close.

[0086] Optionally, the control module is further configured to calculate a first distance between each two peak values ​​when it is determined that the target state value dV / dQ of the battery cell group has at least two peak values ​​based on the charge and voltage of the single battery cell group during the charging process.

[0087] The control module is further configured to calculate a second spacing between each two peaks based on the charge and voltage of the target battery cell group during the recharging process. If a second spacing exists that is larger than the first spacing, the target state value of the target battery cell group is determined to have an increased spacing between at least two peaks, thereby determining that the trend of variation in cell differences within the target battery cell group is increasing, and thereby adjusting the on / off states of the first discharge path and the second discharge path. Conversely, if a second spacing does not exist that is larger than the first spacing, the target state value of the target battery cell group is determined to have a decreased spacing between at least two peaks, thereby determining that the trend of variation in cell differences within the target battery cell group is decreasing, and thereby controlling the first switch module in the target discharge path to close.

[0088] In some embodiments, n=2. The control module is further configured to control the first switch module in the second discharge path connected to the target battery group to close when the distance between two peak values ​​of the target state value of the target battery group is determined to increase based on the charge and voltage of the target battery group during the recharging process. Similarly, the control module is further configured to control the first switch module in the first discharge path connected to the target battery group to close when the distance between two peak values ​​of the target state value of the target battery group is determined to decrease based on the charge and voltage of the target battery group during the recharging process.

[0089] Optionally, when n=2 and a single battery cell group 12 includes two battery cells connected in series, the control module is used to calculate a first distance between two peaks when it is determined that there are at least two peaks in the target state value dV / dQ of the battery cell group based on the charge and voltage of the single battery cell group during the charging process.

[0090] The control module is further configured to determine a second interval between two peak values of the target state value dV / dQ of the target battery cell group according to the charge amount and the voltage of the target battery cell group in the recharging process, and determine that the difference between the battery cells in the target battery cell group increases when the second interval of the target battery cell group is larger than the first interval, and control the first switch module in the second discharge path connected to the target battery cell group to be closed. When the second interval of the target battery cell group is smaller than the first interval, it is determined that the difference between the battery cells in the target battery cell group decreases, and the first switch module in the first discharge path connected to the target battery cell group is controlled to be closed.

[0091] It should be noted that in the case of n = 2, the target state value dV / dQ of the battery cell group 12 has two peak values when the two battery cells in the single battery cell group 12 are in a non-equilibrium state. Please refer to Figure 11 , which shows the change curve of the target state value dV / dQ of the battery cell group 12 with the charge amount Q when the two battery cells in the single battery cell group 12 are in a non-equilibrium state. Figure 11 The target state value dV / dQ of the battery cell group 12 in the non-equilibrium state in the above formula has two peak values P1 and P2. The distance between the two peak values refers to the charge amount difference AQ of the charge amount corresponding to the two peak values, which is the charge amount that needs to be balanced between the two battery cells in the single battery cell group 12.

[0092] Obviously, the second interval of the target battery cell group is larger than the first interval, which can effectively indicate that the difference between the battery cells in the target battery cell group before the control module controls the first switch module in the first discharge path to be closed is smaller than the difference between the battery cells in the target battery cell group after the first switch module in the first discharge path is closed. The discharge of the battery cells connected by the first discharge path aggravates the battery imbalance in the battery cell group.

[0093] Similarly, the second interval of the target battery cell group is smaller than the first interval, which can effectively indicate that the difference between the battery cells in the target battery cell group before the control module controls the first switch module in the first discharge path to be closed is larger than the difference between the battery cells in the target battery cell group after the first switch module in the first discharge path is closed. The discharge of the battery cells connected by the first discharge path can effectively achieve the battery balance in the battery cell group.

[0094] For example, assuming n = 2. The control module can be configured to determine the target cell group 12 as the target cell group in the case that there are two peaks in the target state value dV / dQ of the target cell group 12 determined according to the charge amount and voltage of the single cell group in the charging process, calculate a first interval between the two peaks, and control the first switch module in the first discharge path connected to the target cell group to be closed for a target duration and the first switch module in the second discharge path connected to the target cell group to be open. Then, the control module is further configured to collect the charge amount and voltage of the target cell group in the charging process of the battery module 1 again, determine a second interval between the two peaks in the target state value of the target cell group according to the charge amount and voltage of the target cell group in the recharging process, control the first switch module in the first discharge path to remain open and the first switch module in the second discharge path to be closed in the case that the second interval of the target cell group is larger than the first interval, and control the first switch module in the first discharge path to be closed again and the first switch module in the second discharge path to remain closed in the case that the second interval of the target cell group is smaller than the first interval.

[0095] The target duration is determined according to a preset target discharge amount. That is, the control module controls the first switch module in the first discharge path connected to the target cell group to be closed for a target duration, so that the first discharge path connected cell discharges a target discharge amount, to test whether the discharge of the first discharge path connected cell can reduce the battery imbalance degree in the target cell group, realize battery balancing, so as to facilitate the adjustment of the target cell group discharge cell according to the charge amount and voltage of the target cell group in the recharging process of the battery module 1. For example, the value range of the target discharge amount can be [0.5%, 1%]. Moreover, the value of the target discharge amount can be directly proportional to the first interval (i.e. the charge amount difference AQ). For example, the target discharge amount can be 0.5% or 0.1%, etc.

[0096] For example, assuming that the battery cell group (B1, B2) 12 is the target battery cell group. The control module can first control the first switch module K1_1 in the first discharge path connected with the battery cell B1 to be closed for a target duration, and control the first switch module K1_1 in the second discharge path connected with the battery cell B2 to be disconnected. Then, during the recharging of the battery module 1, the charge amount and voltage of the target battery cell group during the recharging of the battery module 1 are collected. According to the charge amount and voltage of the target battery cell group during the recharging, if it is determined that the target state value dV / dQ of the target battery cell group increases between the two peaks, the control module controls the first switch module K1_1 in the first discharge path connected with the battery B1 to be disconnected, and controls the first switch module K1_2 in the second discharge path connected with the battery B2 to be closed; if it is determined that the target state value dV / dQ of the target battery cell group decreases between the two peaks, the control module controls the first switch module K1_1 in the first discharge path connected with the battery B1 to be closed.

[0097] In some embodiments, the control module is further configured to control the first switch module in the target discharge path to be closed for a target equalization duration. The target equalization duration is directly proportional to the second interval. The second interval is the interval between the two peaks of the target state value determined according to the charge amount and voltage of the target battery cell group during the recharging.

[0098] That is, the control module is further configured to control the first switch module in the target discharge path to be closed for a target equalization duration in the case where the difference between the battery cells in the target battery cell group decreases (the two peaks of the target state value dV / dQ decrease) according to the charge amount and voltage of the target battery cell group during the recharging.

[0099] The target equalization duration is directly proportional to the second interval. That is, the longer the second interval, the greater the amount of charge that needs to be equalized between the n battery cells in a single battery cell group 12, the longer the target equalization duration, the longer the connection time of the discharge circuit of the battery cell that needs to be discharged, and the longer the discharge duration of the battery cell that needs to be discharged. For example, taking n=2 as an example, according to the case where the difference between the battery cells in the target battery cell group increases according to the charge amount and voltage of the target battery cell group during the recharging, it can be determined that the battery cell connected with the second discharge path is the battery cell that needs to be discharged, and the discharge of the battery cell can achieve battery equalization. Therefore, the control module can be configured to control the first switch module in the second discharge path to be closed for a target equalization duration, so that the battery cell connected with the second discharge path is discharged for a target equalization duration. Correspondingly, according to the case where the difference between the battery cells in the target battery cell group decreases according to the charge amount and voltage of the target battery cell group during the recharging, it can be determined that the battery cell connected with the first discharge path is the battery cell that needs to be discharged, and the discharge of the battery cell can achieve battery equalization. Therefore, the control module can be configured to control the first switch module in the first discharge path to be closed for a target equalization duration, so that the battery cell connected with the first discharge path is discharged for a target equalization duration.

[0100] Optionally, in the case that the first discharge path 11 comprises the first load and the first switch module, the target equalization duration can also be determined according to the second interval and the resistance value of the first resistor. Specifically, the target equalization duration can be the ratio of the second interval and the resistance value of the first load. Alternatively, the target equalization duration can be the ratio of the second interval and the resistance value of the first load, and the sum of the preset discharge margin.

[0101] As shown in FIG. 1, the battery module 1 further comprises a second discharge path 13. Two poles of each of the cell groups 12 are connected by one second discharge path 13. The second discharge path 13 comprises a second switch module and a second load connected to the second switch module. The second switch module is used to conduct the second discharge path 13 and the cell group 12 when closed, forming a discharge loop of the cell group 12. The discharge loop of the cell group 12 is used to discharge the whole cell group 12 to achieve battery equalization of the battery module. Figure 1

[0102] The control module is further connected to the second switch module and is used to control the second switch module to be closed or opened according to the charge amount and voltage of each of the cell groups 12 during the charging process.

[0103] In an alternative case, as shown in FIG. 2, one pole of the single cell group 12 is connected to one end of the second switch module in the second discharge path 13, and the other end of the second switch module is connected to the other pole of the cell group 12 through the second load. Figure 1

[0104] Correspondingly, the control module is used to control the second switch module in the second discharge path 13 connected to the cell group 12 to be closed, and the second switch modules in the second discharge paths 13 connected to the other cell groups 12 to be opened, so that the whole cell group 12 is discharged to achieve battery equalization of the battery module, when any one of the cell groups 12 needs to be discharged to perform battery equalization.

[0105] In another alternative case, as shown in FIG. 3, one pole of the single cell group 12 is connected to one end of the second switch module in the second discharge path 13, and the other end of the second switch module is connected to the other pole of the cell group 12 through the second load. Figure 2 ​​As shown, two secondary discharge paths 13 of two cell groups 12 connected in series directly share one second load. Correspondingly, in the case that the first cell group needs to be discharged to perform battery balancing, the control module can be used to control the second switch module of the secondary discharge path 13 connected by the first cell group to be closed, and control the second switch module of the secondary discharge path 13 connected by the second cell group to be opened. Similarly, in the case that the second cell group needs to be discharged to perform battery balancing, the control module can be used to control the second switch module of the secondary discharge path 13 connected by the second cell group to be closed, and control the second switch module of the secondary discharge path 13 connected by the first cell group to be opened. It should be noted that the two second switch modules connected by the first cell group and the second cell group cannot be closed at the same time to avoid causing the cell group to be short-circuited. Therefore, if both the first cell group and the second cell group need to be discharged to perform battery balancing, the control module can first control the second switch module of the secondary discharge path 13 connected by the first cell group (the second cell group) to be closed, and control the second switch module of the secondary discharge path 13 connected by the second cell group (the first cell group) to be opened; and then control the second switch module of the secondary discharge path 13 connected by the second cell group (the first cell group) to be closed, and control the second switch module of the secondary discharge path 13 connected by the first cell group (the second cell group) to be opened.

[0106] It should be noted that, in order to better identify the second switch modules and the second loads in the secondary discharge paths 13 connected by different cell groups 12, Figure 1 in the second switch modules K2_1-K2_4 and the second loads R2_1-R2_4 respectively identify the second switch modules and the second loads in the secondary discharge paths 13 connected by the four cell groups 12. Figure 2 in the second switch modules K2_1-K2_4 and the second loads R2_1-R2_2 respectively identify the second switch modules and the second loads in the secondary discharge paths 13 connected by the four cell groups 12.

[0107] For a specific example, please continue to refer to Figure 2 , n is 2. The battery module 1 includes eight primary discharge paths 11 and eight series-connected cells B1-B8. The eight series-connected cells B1-B8 include four cell groups 12, which are cell group (B1, B2) 12, cell group (B3, B4) 12, cell group (B5, B6) 12, and cell group (B7, B8) 12. Cell group (Bi, Bj) represents a cell group including cell Bi and cell Bj.

[0108] And, the two-pole connected first discharge path 11 of the battery cell B1 includes the first switch module K1_1 and the first load R1_1. The two-pole connected first discharge path 11 of the battery cell B2 includes the first switch module K1_2 and the multiplexed first load R1_1, and so on. The two-pole connected first discharge path 11 of the battery cell B7 includes the first switch module K1_7 and the first load R1_4. The two-pole connected first discharge path 11 of the battery cell B8 includes the first switch module K1_8 and the multiplexed first load R1_4. The two-pole connected second discharge path 13 of the battery cell group (B1, B2) 12 includes the second switch module K2_1 and the second load R2_1. The two-pole connected second discharge path 13 of the battery cell group (B3, B4) 12 includes the second switch module K2_2 and the multiplexed second load R2_1. The two-pole connected second discharge path 13 of the battery cell group (B5, B6) 12 includes the second switch module K2_3 and the second load R2_2. The two-pole connected second discharge path 13 of the battery cell group (B7, B8) 12 includes the second switch module K2_4 and the multiplexed second load R2_2.

[0109] The control module is connected to the two poles of the battery cell group (B1, B2), the battery cell group (B3, B4), the battery cell group (B5, B6), and the battery cell group (B7, B8) respectively, and is connected to the first switch module K1_1-K1_8 and the second switch module K2_1-K2_4 respectively.

[0110] The control module is configured to collect the charge amount and voltage of each battery cell group 12 in the battery module 1 during charging, and determine whether each battery cell group 12 is a target battery cell group that needs to be balanced according to the charge amount and voltage of the battery cell group 12 during charging. Further, the control module is configured to control the first switch module in the target discharge path to be closed and the first switch module in other discharge paths to be kept open when it is determined that the battery cell group 12 is a target battery cell group that needs to be balanced according to the charge amount and voltage of the battery cell group 12, so that the target battery cell (i.e. the battery cell that needs to be discharged) in the target battery cell group is connected to its first discharge path, forming a discharge loop of the target battery cell, discharging the target battery cell, and achieving battery balancing for each battery cell in the battery cell group 12, i.e. achieving intra-group battery balancing of the battery cell group 12.

[0111] The control module is further configured to control the second switch module to be closed or opened according to the voltage and charge amount of each battery cell group 12 when it is determined that battery balancing is needed between the battery cell groups of the battery module 1 according to the charge amount and voltage of each battery cell group 12 during charging, so as to reduce the difference between the battery cells of the battery cell groups 12, achieve battery balancing for each battery cell group 12, i.e. achieve inter-group battery balancing of the battery cell group 12, and enable the battery module 1 as a whole to achieve battery balancing.

[0112] In some embodiments, the control module is further configured to perform battery equalization on the battery module by taking each of the plurality of groups of cells as one cell according to the voltage and the charge amount of each of the plurality of groups of cells during charging, to obtain an equalization result, and to control the second switch module in the secondary discharge path connected to each of the plurality of groups of cells to be closed or opened according to the equalization result, to realize group-to-group battery equalization of the plurality of groups of cells 12. The equalization result at least indicates whether each of the plurality of groups of cells needs to be discharged. The control module is configured to control the second switch module connected to the third group of cells in the battery module 1 to be closed according to the equalization result, and to control the second switch module connected to each of the plurality of groups of cells other than the third group of cells in the battery module 1 to be opened. The third group of cells is the group of cells that needs to be discharged according to the equalization result.

[0113] In one example, the battery equalization performed by taking each of the plurality of groups of cells as one cell can include calculating the average voltage of all the plurality of groups of cells 12, determining the group of cells with a voltage greater than the average voltage as the group of cells that needs to be discharged, determining the group of cells with a voltage less than or equal to the average voltage as the group of cells that does not need to be discharged, and generating the equalization result.

[0114] In another example, the battery equalization performed by taking each of the plurality of groups of cells as one cell can include calculating the range of the voltage of all the plurality of groups of cells 12, determining the group of cells with a voltage greater than the voltage threshold as the group of cells that needs to be discharged, determining the group of cells with a voltage less than or equal to the voltage threshold as the group of cells that does not need to be discharged, and generating the equalization result. The control module can also be configured to calculate the difference between the charge amount of the group of cells that needs to be discharged and the charge amount of the group of cells that does not need to be discharged, to discharge the group of cells that needs to be discharged so that the charge amount of the group of cells after discharge is different from the charge amount of the group of cells before discharge by the difference.

[0115] In this way, the control module can collect the voltage and the charge amount of the plurality of groups of cells each composed of n series of cells to determine whether each of the cells in the group of cells needs to be equalized, thereby realizing intra-group battery equalization of the group of cells. In addition, the control module can also collect the voltage of each of the plurality of groups of cells to determine whether the plurality of groups of cells needs to be equalized, thereby realizing group-to-group battery equalization of the plurality of groups of cells to realize overall battery equalization of the battery module. Therefore, compared with the related art which needs to collect the voltage of each of the cells to realize battery equalization, the present application can effectively reduce the voltage sampling cost in the battery equalization process.

[0116] It should be noted that in some embodiments, the control module can also take the n adjacent series of battery cells as a larger battery cell group (i.e. battery cell large group) to control the second switch module in the secondary discharge path connected to the battery cell group that needs to be discharged to close, so as to make the battery cell group that needs to be discharged discharge, realize the inter-group battery balancing of the battery cell group, and realize the overall battery balancing of the battery module by cooperating to realize the intra-group balancing and inter-group balancing of the battery cell group. Wherein, the specific implementation mode of the control module taking the n adjacent series of battery cell groups as a battery cell group to realize the inter-group battery balancing of the battery cell group can refer to the specific implementation mode of the intra-group battery balancing of the battery cell group described above, and the embodiments of the present application will not be repeated here.

[0117] In the embodiments of the present application, the battery assembly includes a battery module and a control module. The battery module includes a primary discharge path and a plurality of series of battery cells. The two poles of each battery cell are connected by a primary discharge path, and the primary discharge path includes a first switch module and a first load connected to the first switch module. Every n series of battery cells in the battery module is a battery cell group. The control module is connected to the two poles of each battery cell group and the first switch module, and is used to control the first switch module in the primary discharge path connected to the battery cell that needs to be discharged to close in the case of determining that the battery cell group is the target battery cell group that needs to be balanced according to the charge amount and voltage of the single battery cell group in the charging process, so as to turn on the primary discharge path connected to the battery cell that needs to be discharged, form a discharge loop of the battery cell, discharge the battery cell, and realize the battery balancing of the battery cell group.

[0118] Since the control module in the technical solution can collect the voltage and charge amount of at least one battery cell group composed of n series of battery cells to determine whether the battery cell group needs to be balanced, thereby realizing the battery balancing of the battery cell group. Therefore, compared with the way of collecting the voltage of each battery cell to realize the battery balancing in the related art, the present application can effectively reduce the voltage sampling cost in the battery balancing process and improve the voltage sampling efficiency.

[0119] The embodiment of the present application further provides an electronic device. The electronic device comprises the battery assembly provided by the embodiment of the present application. In the electronic device provided by the embodiment of the present application, the battery assembly comprises a battery module and a control module. The battery module comprises a primary discharge path and a plurality of series-connected battery cells. Two poles of each battery cell are connected through a primary discharge path, and the primary discharge path comprises a first switch module and a first load connected with the first switch module. Every n series-connected battery cells in the battery module form a battery cell group. The control module is connected with two poles of each battery cell group and the first switch module, and is configured to, in a case where it is determined according to the charge amount and the voltage of a single battery cell group in a charging process that the battery cell group is a target battery cell group that needs to be balanced, control the first switch module in a primary discharge path connected with a battery cell that needs to be discharged in the target battery cell group to be closed, so as to turn on the primary discharge path connected with the battery cell that needs to be discharged, form a discharge loop of the battery cell, discharge the battery cell, and realize battery balancing of the battery cell group.

[0120] In the technical solution, the control module can collect the voltage and the charge amount of at least one battery cell group comprising n series-connected battery cells, to determine whether the battery cell group needs to be balanced, so as to realize battery balancing of the battery cell group. Therefore, compared with the manner in the related art that needs to collect the voltage of each battery cell to realize battery balancing, the present application can effectively reduce the voltage sampling cost in the battery balancing process and improve the voltage sampling efficiency.

[0121] The embodiment of the present application further provides a flowchart of a battery balancing method. The battery balancing method can be applied to the battery assembly provided by the embodiment of the present application or the electronic device provided by the embodiment of the present application, and is executed by the control module in the battery assembly. The battery balancing method comprises the following steps.

[0122] In a case where it is determined according to the charge amount and the voltage of a single battery cell group in a charging process that the battery cell group is a target battery cell group that needs to be balanced, the first switch module in a target discharge path is controlled to be closed.

[0123] In the technical solution, the control module can collect the voltage and the charge amount of at least one battery cell group comprising n series-connected battery cells, to determine whether the battery cell group needs to be balanced, so as to realize battery balancing of the battery cell group. Therefore, compared with the manner in the related art that needs to collect the voltage of each battery cell to realize battery balancing, the present application can effectively reduce the voltage sampling cost in the battery balancing process and improve the voltage sampling efficiency.

[0124] In the embodiment of the present application, the control module can collect the charge amount and voltage of each cell group of the battery module during the charging process, so as to control the first switch module connected in the first discharge path of the cell that needs to be discharged to be closed in the case that the cell group is determined to be the target cell group that needs to be balanced according to the charge amount and voltage of the single cell group during the charging process, so as to turn on the first discharge path connected with the cell that needs to be discharged, form a discharge loop of the cell, discharge the cell, and realize the battery balancing of the cell group. In the technical solution, the control module can collect the voltage and charge amount of at least one cell group composed of n series connected cells to determine whether the cell group needs to be balanced, so as to realize the battery balancing of the cell group. Therefore, compared with the method of collecting the voltage of each cell to realize the battery balancing in the related art, the voltage sampling cost in the battery balancing process can be effectively reduced, and the voltage sampling efficiency can be improved.

[0125] Optionally, the process of determining the cell group as the target cell group that needs to be balanced according to the change characteristics of the charge amount and voltage of the single cell group during the charging process can include: determining the cell group as the target cell group that needs to be balanced according to the change characteristics of the charge amount and voltage of the single cell group during the charging process.

[0126] Optionally, the battery balancing method further includes: obtaining the charging current and the battery state of charge of the battery module during the charging process; and the process of determining the cell group as the target cell group that needs to be balanced according to the change characteristics of the charge amount and voltage of the single cell group during the charging process can include:

[0127] In the case that the charging current is less than or equal to the target current, and the change process of the battery state of charge includes at least the target state range, the cell group is determined as the target cell group that needs to be balanced according to the change characteristics of the charge amount and voltage of the single cell group during the charging process. The values of the target current and the target state range are related to the existence condition of the charging inflection point of the battery module.

[0128] Optionally, the process of determining the cell group as the target cell group that needs to be balanced according to the change characteristics of the charge amount and voltage of the single cell group during the charging process can include: in the case that the target state value of the cell group has at least two peaks according to the charge amount and voltage of the single cell group during the charging process, the cell group is determined as the target cell group.

[0129] Optionally, in the case where there are at least two peaks in the target state value of the single cell group according to the charge amount and voltage of the single cell group during the charging process, the process of determining the cell group as the target cell group can include: determining the cell group as the target cell group according to the derivative value of the voltage with respect to the charge amount of each cell group during the charging process, in the case where there are at least two peaks in the derivative value of the single cell group during the charging process.

[0130] Optionally, in the case where the cell group is determined as the target cell group that needs to be balanced according to the charge amount and voltage of the single cell group during the charging process, the process of controlling the first switch module in the target discharge path to be closed can include:

[0131] In the case where the cell group is determined as the target cell group that needs to be balanced according to the charge amount and voltage of the single cell group during the charging process, the process of controlling the first switch module in the first discharge path connected by the target cell group to be closed for a target duration, and the first switch module in the second discharge path connected by the target cell group to be disconnected, and determining the change trend of the difference between the cells in the target cell group according to the charge amount and voltage of the target cell group during the recharging process, and controlling the first switch module in the target discharge path to be closed according to the change trend, wherein the n primary discharge paths connected by the target cell group are composed of the first discharge path and the second discharge path.

[0132] Further optionally, the process of determining the change trend of the difference between the cells in the target cell group according to the charge amount and voltage of the target cell group during the recharging process, and controlling the first switch module in the target discharge path to be closed according to the change trend can include:

[0133] In the case where the interval between the at least two peaks in the target state value of the target cell group is determined to increase according to the charge amount and voltage of the target cell group during the recharging process, the change trend is determined to increase, and the on-off state of the first discharge path and the second discharge path is adjusted.

[0134] In the case where the interval between the at least two peaks in the target state value of the target cell group is determined to decrease according to the charge amount and voltage of the target cell group during the recharging process, the change trend is determined to decrease, and the first switch module in the target discharge path is controlled to be closed, and the target discharge path is the primary discharge path in which the first switch module was closed by the control module in the previous control.

[0135] In some embodiments, n = 2. The process of determining the change trend of the difference between the cells in the target cell group according to the charge amount and voltage of the target cell group during the recharging process, and controlling the first switch module in the target discharge path to be closed according to the change trend can include:

[0136] In a case that the second interval between the two peaks of the target state value of the target cell group is increased according to the charge amount and voltage of the target cell group in the recharging process, the first switch module in the second discharging path (i.e. the target discharging path) is controlled to be closed.

[0137] In a case that the second interval between the two peaks of the target state value of the target cell group is decreased according to the charge amount and voltage of the target cell group in the recharging process, the first switch module in the first discharging path (i.e. the target discharging path) is controlled to be closed.

[0138] For example, n = 2. In the battery equalization method, in a case that a single cell group is determined to be the target cell group according to the charge amount and voltage of the single cell group in the charging process, the first switch module in the first discharging path to which the target cell group is connected is controlled to be closed for a target duration, and the first switch module in the second discharging path to which the target cell group is connected is controlled to be opened. The first interval between the two peaks of the target state value of the target cell group is calculated according to the charge amount and voltage of the target cell group in the charging process.

[0139] After the battery module 1 is recharged, the second interval between the two peaks of the target state value of the target cell group is calculated according to the charge amount and voltage of the target cell group in the recharging process. In a case that the second interval of the target cell group is increased compared with the first interval, it is determined that the difference between the cells in the target cell group is increased, and the first switch module in the second discharging path to which the target cell group is connected is controlled to be closed. In a case that the second interval of the target cell group is decreased compared with the first interval, it is determined that the difference between the cells in the target cell group is decreased, and the first switch module in the first discharging path to which the target cell group is connected is controlled to be closed.

[0140] Optionally, the process of controlling the first switch module in the target discharging path to be closed can include: controlling the first switch module in the target discharging path to be closed for a target equalization duration. The target equalization duration is proportional to the second interval. Optionally, the target equalization duration can also be determined according to the second interval and the resistance value of the first resistor. Further optionally, the target equalization duration is the ratio of the second interval to the resistance value of the first resistor.

[0141] Optionally, the battery equalization method further includes: controlling the second switch module to be closed or opened according to the voltage and charge amount of each cell group, so as to reduce the difference between the cells in the cell groups and achieve the assembly battery equalization of the cell groups.

[0142] In an alternative implementation, the process of controlling the second switch module to be closed or opened according to the voltage and charge amount of each cell group can include: taking a single cell group as one cell, performing battery equalization on the battery module according to the voltage and charge amount of each cell group during the charging process to obtain an equalization result, and controlling the second switch module in the secondary discharge path connected by each cell group to be closed or opened according to the equalization result. The equalization result at least indicates whether each cell group needs to be discharged.

[0143] In another alternative implementation, n adjacent series-connected cell groups are taken as one larger cell group (i.e., a cell large group) to control the second switch module in the secondary discharge path connected by the cell group that needs to be discharged in the cell large group to be closed to discharge the cell group that needs to be discharged in the cell large group, so as to realize inter-group battery equalization of the cell group, and to realize overall battery equalization of the battery module by coordinating the realization of intra-group equalization and inter-group equalization of the cell group. The specific implementation of the control module taking n adjacent series-connected cell groups as one cell large group to realize inter-group battery equalization of the cell group can refer to the specific implementation of the intra-group battery equalization of the cell group described above, and the embodiments of the present application will not be repeated here.

[0144] In the embodiments of the present application, the control module can collect the charge amount and voltage of each cell group of the battery module during the charging process, so as to control the first switch module in the primary discharge path connected by the cell that needs to be discharged in the target cell group to be closed to turn on the primary discharge path connected by the cell that needs to be discharged, so as to form a discharge loop of the cell, discharge the cell, and realize battery equalization of the cell group, in the case that the cell group is determined to be a target cell group that needs to be equalized according to the charge amount and voltage of the single cell group during the charging process. Since the control module in this technical solution can collect the voltage and charge amount of at least one cell group composed of n series-connected cells to determine whether the cell group needs to be equalized, thereby realizing battery equalization of the cell group. Therefore, compared with the way of collecting the voltage of each cell to realize battery equalization in the related art, the present application can effectively reduce the voltage sampling cost in the battery equalization process and improve the voltage sampling efficiency.

[0145] For ease of understanding, the battery equalization method provided by the embodiments of the present application is further illustratively described below by way of example. It is assumed that n is 2, and a single cell group includes a first cell and a second cell. As shown in Figure 12 The battery equalization method includes:

[0146] In the case that the battery module 1 enters the equalization mode after the charging is completed, the charge amount and the voltage of each cell group of the battery module during the charging process are collected. For each cell group, the derivative value of the voltage to the charge amount during the charging process is calculated to obtain a plurality of target state values dV / dQ. It is judged whether the plurality of target state values dV / dQ of the cell group have two peak values, that is, whether the curve of the target state value dV / dQ with respect to the charge amount Q has two peak values. If yes, the intra-group cell equalization processing is performed; if no, the inter-group battery equalization processing is performed.

[0147] The intra-group cell equalization processing includes: calculating a first interval (i.e., a first charge amount difference AQ) between the two peak values, and then controlling the first switch module in the first discharge path connected to the first battery (the second cell) to be closed for a first time length. The charge amount and the voltage of the cell group of the battery module during the charging process are collected again. According to the charge amount and the voltage of the cell group, the second interval between the two peak values of the target state value dV / dQ of the cell group is determined. In the case that the second interval is increased compared with the first interval, the first switch module connected to the first battery (the second cell) is controlled to be opened, and the first switch module in the second discharge path connected to the second cell (the first cell) is controlled to be closed. In the case that the second interval is decreased compared with the first interval, the first switch module connected to the first battery (the second cell) is controlled to be kept closed for a target equalization time length, so as to realize the intra-group battery equalization of the cell group 12.

[0148] The inter-group battery equalization processing includes: regarding a single cell group as a cell, performing the battery equalization processing on the battery module according to the voltage of each cell group to obtain an equalization processing result, and controlling the second switch module in the secondary discharge path connected to each cell group to be closed or opened according to the equalization processing result, so as to realize the inter-group battery equalization of the cell group 12.

[0149] In the embodiments of the present application, the control module can collect the charge amount and the voltage of each cell group of the battery module during the charging process, so as to determine the target cell group that needs to be equalized according to the charge amount and the voltage of a single cell group during the charging process, control the first switch module in the primary discharge path connected to the cell that needs to be discharged in the target cell group to be closed, so as to turn on the primary discharge path connected to the cell that needs to be discharged, form a discharge loop of the cell, discharge the cell, and realize the battery equalization of the cell group. In the technical solution, the control module can collect the voltage and the charge amount of at least one cell group composed of n series-connected cells, so as to determine whether the cell group needs to be equalized, and thus the battery equalization of the cell group is realized. Therefore, compared with the manner in which the voltage of each cell is collected to realize the battery equalization in the related art, the voltage sampling cost in the battery equalization process can be effectively reduced, and the voltage sampling efficiency is improved.

[0150] In the embodiments described above, all or some of the steps can be implemented by software, hardware or firmware, or any combination thereof. When implemented by software, all or some of the steps can be implemented in the form of one or more computer programs. The computer program can be stored in any computer readable medium, and when loaded into a computer system, causes the computer system to perform one or more of the steps of the computer program. The computer readable medium can be a magnetic disk, an optical disk or a solid state drive, or any combination thereof. The computer readable medium can be distributed to computer systems connected by a network, so that the computer programs that constitute the computer programs (which can also be in the form of computer readable medium) can be stored in and executed by the network connected computer systems in a distributed manner.

[0151] It should be noted that, in the present document, the terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Also, the terms "comprising", "containing" or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, article or apparatus that comprises a list of elements does not only include those elements, but also other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, an element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0152] Each of the embodiments in the present specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. For the embodiments of the apparatus, electronic device, computer readable storage medium and computer program product containing instructions thereof, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiments.

[0153] The above merely provides preferred embodiments of the application, and not for limiting the protective scope of the application. Any modification, equivalent replacement, improvement, etc. made within the principle and technical scope of the application shall fall into the protective scope of the application.

Claims

1. A battery assembly, characterized in that: The battery assembly includes: a battery module and a control module; The battery module includes a primary discharge path and a plurality of battery cells connected in series, wherein every n battery cells connected in series form a battery cell group, and the two electrodes of each battery cell are connected via one of the primary discharge paths. The primary discharge path includes a first switch module and a first load connected to the first switch module. The first switch module is configured to conduct the primary discharge path and the battery cell when closed, thereby forming a discharge circuit for the battery cell. The control module is connected to the two poles of each cell group and the first switch module, and is used to control the first switch module in the target discharge path to close when the cell group is determined to be a target cell group that needs to be balanced based on the charge and voltage of the single cell group during charging. The target discharge path is the primary discharge path connected to the cell that needs to be discharged in the target cell group; The control module is also used to determine that the battery group is the target battery group when it is determined that the target state value of the battery group has at least two peaks based on the charge and voltage of a single battery group during the charging process, and the target state value is the instantaneous rate of change of voltage with charge.

2. The battery assembly according to claim 1, wherein: The control module is further configured to determine, based on a derivative value of the voltage of each cell group with respect to the charge amount, that the cell group is the target cell group when the derivative value of a single cell group during the charging process has at least two peaks.

3. The battery assembly according to claim 1, wherein: The control module is also used to control the first switch module in the first discharge path connected to the target battery group to close for a target duration, and to disconnect the first switch module in the second discharge path connected to the target battery group, when the battery group is determined to be a target battery group that needs to be balanced based on the charge and voltage of a single battery group during the charging process; and to determine the changing trend of the battery cell differences in the target battery group based on the charge and voltage of the target battery group during the recharging process, and to control the first switch module in the target discharge path to close based on the changing trend, wherein the n primary discharge paths connected to the target battery group are composed of the first discharge path and the second discharge path.

4. The battery assembly according to claim 3, characterized in that The control module is further configured to, when determining, based on the charge and voltage of the target battery cell group during recharging, that the distance between at least two peaks of the target state value of the target battery cell group is increasing, determine that the change trend is increasing, and adjust the on / off states of the first discharge path and the second discharge path.

5. The battery assembly according to claim 4, characterized in that n＝2； The control module is further configured to control the first switch module in the second discharge path to close when it is determined that the distance between two peaks of the target state value of the target battery group increases according to the charge and voltage of the target battery group during recharging.

6. The battery assembly according to claim 3, characterized in that The control module is also used to determine that the change trend is decreasing when it is determined that the distance between at least two peaks of the target state value of the target battery group is decreasing based on the charge and voltage of the target battery group during the recharging process, and to control the first switch module in the target discharge path to be closed. The target discharge path is the first-level discharge path that the control module controlled the first switch module to be closed the last time.

7. The battery assembly according to claim 6, characterized in that n＝2； The control module is further configured to control the first switch module in the first discharge path to close when the charge amount and voltage of the target battery group during recharging determine a decrease between two peaks of the target state value of the target battery group.

8. The battery assembly according to claim 3, wherein: The control module is further configured to control the closing of the first switch module in the target discharge path for a target balancing time, wherein the target balancing time is proportional to a second spacing, and the second spacing is the spacing between two peaks of a target state value determined based on the charge and voltage of the target battery cell group during recharging.

9. The battery assembly according to claim 8, characterized in that The target balancing time is determined according to the second distance and the resistance value of the first load.

10. The battery assembly according to claim 9, characterized in that The target balancing time is a ratio of the second distance to the resistance of the first load.

11. The battery assembly according to claim 1, wherein: The control module is also used to determine that the battery group is a target battery group that needs to be balanced based on the change characteristics of the charge and voltage of a single battery group during the charging process, when the charging current of the battery module during the charging process is less than or equal to the target current and the change history of the battery charge state of the battery module at least includes the target state range, wherein the values ​​of the target current and the target state range are related to the existence conditions of the charging inflection point of the battery module.

12. The battery assembly according to any one of claims 1 to 11, characterized in that: n=2, the battery cell group includes a first battery cell and a second battery cell; The two primary discharge paths connected to the same battery cell group share one first load.

13. The battery assembly according to any one of claims 1 to 11, characterized in that: The battery module further includes: a secondary discharge path, wherein the two electrodes of each battery cell group are connected via one of the secondary discharge paths, the secondary discharge path including a second switch module and a second load connected to the second switch module, wherein the second switch module is configured to conduct the secondary discharge path and the battery cell group when closed, thereby forming a discharge circuit for the battery cell group; The control module is also connected to the second switch module, and is used to control the second switch module to be closed or opened according to the voltage and charge amount of each battery cell group during the charging process.

14. The battery assembly according to claim 13, wherein: The control module is further configured to treat a single cell group as a cell, perform battery balancing on the battery module according to the voltage and charge of each cell group during charging, obtain a balancing result, and control the second switch module in the secondary discharge path connected to each cell group to close or open according to the balancing result. The balancing result at least indicates whether each cell group needs to be discharged.

15. The battery assembly according to claim 13, wherein: The two secondary discharge paths of the two battery cell groups directly connected in series share one second load.

16. An electronic device, characterized in that: The electronic device comprises the battery assembly according to any one of claims 1 to 15.

17. A battery balancing method, characterized in that: Applied to the battery assembly according to any one of claims 1 to 15, or the electronic device according to claim 16, the method comprising: When the cell group is determined to be a target cell group that needs to be balanced based on the charge and voltage of the single cell group during charging, the first switch module in the target discharge path is controlled to be closed. The target discharge path is the primary discharge path connected to the battery cells that need to be discharged in the target battery cell group.

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