Electric quantity balance control method, device and system

Abstract

The embodiment of the invention discloses an electric quantity balance control method, device and system. The electric quantity balance control method comprises the following steps: acquiring charging data and discharging data of a target battery cluster, wherein the target battery cluster comprises a plurality of battery modules which are connected in series; according to the charging data and the discharging data, determining a target electric quantity range and cluster average voltage and module average voltage under different electric quantities in the target electric quantity range; performing successive offset on the electric quantity corresponding to the module average voltage based on a preset offset step length to obtain the module average voltage corresponding to the electric quantity after each offset; and fitting the cluster average voltage and the module average voltage corresponding to the electric quantity after each offset, determining the target offset electric quantity of the battery module, and performing electric quantity balance control according to the target offset electric quantity. According to the electric quantity balance control method, device and system provided by the embodiment of the invention, the control reliability can be ensured.

Description

Technical Field

[0001] The embodiments of the present invention relate to power control technology, and more particularly to a power balancing control method, device and system. Background Technology

[0002] In new energy systems, the battery cluster is the basic management unit. Each battery cluster contains multiple battery modules, and each battery module comprises multiple individual battery cells (cells). These cells are connected in series and parallel. In actual use, due to internal differences among individual battery cells or variations in external operating conditions, the charge levels between battery modules cannot be balanced, affecting the lifespan of the battery cluster. Therefore, it is necessary to implement charge balancing control for the battery cluster.

[0003] Currently, existing power balancing control methods typically generate balancing control schemes based on real-time sampled data. These methods rely on a single metric, and the representativeness of instantaneous data is insufficient, making them susceptible to affecting control reliability due to sampling errors and data jitter. Summary of the Invention

[0004] This invention provides a power balancing control method, apparatus, and system to ensure control reliability.

[0005] In a first aspect, embodiments of the present invention provide a power balancing control method, comprising:

[0006] Acquire charging and discharging data of a target battery cluster, which includes multiple battery modules connected in series;

[0007] Based on the charging data and the discharging data, determine the target power range, the cluster average voltage and the module average voltage at different power levels within the target power range;

[0008] Based on a preset offset step size, the power corresponding to the average voltage of the module is successively offset to obtain the average voltage of the module corresponding to the power after each offset.

[0009] The average voltage of the cluster and the average voltage of the module corresponding to the power level after each offset are fitted to determine the target offset power level of the battery module, so as to perform power balance control based on the target offset power level.

[0010] Optionally, fitting the cluster average voltage and the module average voltage corresponding to the charge level after each offset to determine the target offset charge level of the battery module includes:

[0011] Linear fitting is performed on the cluster average voltage and the module average voltage corresponding to the power after each offset to determine the correlation coefficient between the fitted cluster average voltage and the module average voltage corresponding to each offset;

[0012] The target offset capacity of the battery module is determined based on the correlation coefficient corresponding to each offset.

[0013] Optionally, determining the target offset capacity of the battery module based on the correlation coefficient corresponding to each offset includes:

[0014] Based on the correlation coefficients corresponding to each offset, determine the largest correlation coefficient among each offset;

[0015] The difference is obtained by subtracting the energy level after the shift corresponding to the largest correlation coefficient in each shift from the energy level at the zero shift.

[0016] The difference is used as the target offset power of the battery module.

[0017] Optionally, the power balancing control based on the target offset power includes:

[0018] Based on the target offset, control the battery modules in the target battery cluster whose target offset is less than zero to transfer energy to the battery modules whose target offset is greater than zero.

[0019] Optionally, the battery module includes multiple individual batteries connected in series, and the charging data and the discharging data both include the real-time voltage of each individual battery and the real-time power of the target battery cluster.

[0020] The step of determining the target power range, the cluster average voltage, and the module average voltage at different power levels within the target power range based on the charging data and the discharging data includes:

[0021] The sum of the real-time voltages of each individual cell in the target battery cluster, and the ratio of the total number of individual cells in the target battery cluster, are used as the cluster average voltage.

[0022] The average voltage of the module is the ratio of the sum of the real-time voltages of each individual cell in the battery module to the number of individual cells included in the battery module.

[0023] Optionally, the step of successively shifting the power corresponding to the average voltage of the module based on a preset shift step size to obtain the average voltage of the module corresponding to the power after each shift includes:

[0024] If there is no corresponding average module voltage for the offset power, then the interpolation method is used to determine the average module voltage corresponding to the offset power.

[0025] If the battery level after multiple offsets exceeds the target battery level range, the average voltage of the module corresponding to the battery level exceeding the target battery level range will be deleted.

[0026] Optionally, the preset offset step size is between 0.02% and 0.1% of the rated capacity of the battery module.

[0027] Secondly, embodiments of the present invention provide a power balancing control device, comprising:

[0028] The data acquisition module is used to acquire charging and discharging data of the target battery cluster, which includes multiple battery modules connected in series.

[0029] The voltage determination module is used to determine the target power range, the cluster average voltage and the module average voltage under different power levels within the target power range, based on the charging data and the discharging data.

[0030] The power offset module is used to successively offset the power corresponding to the average voltage of the module based on a preset offset step size, so as to obtain the average voltage of the module corresponding to the power after each offset.

[0031] The equalization control module is used to fit the cluster average voltage and the module average voltage corresponding to the power after each offset to determine the target offset power of the battery module, so as to perform power equalization control based on the target offset power.

[0032] Thirdly, embodiments of the present invention provide a power management system, including a data acquisition module and a controller, wherein the data acquisition module is electrically connected to the controller, and the control device as described in the second aspect is integrated into the controller.

[0033] Optionally, the acquisition module corresponds one-to-one with each battery module in the target battery cluster, and the acquisition module is used to acquire the charging data and discharging data of the corresponding battery module.

[0034] The present invention provides a power balancing control method, apparatus, and system. The power balancing control method includes: acquiring charging and discharging data of a target battery cluster, wherein the target battery cluster includes multiple battery modules connected in series; determining a target power range, the cluster average voltage, and the module average voltage at different power levels within the target power range based on the charging and discharging data; successively shifting the power corresponding to the module average voltage based on a preset shift step size to obtain the module average voltage corresponding to the power after each shift; fitting the cluster average voltage and the module average voltage corresponding to the power after each shift to determine the target shift power of the battery module, so as to perform power balancing control based on the target shift power. The power balancing control method, apparatus, and system provided in this invention successively shift the power corresponding to the average voltage of the module to obtain the average voltage of the module after each shift. By fitting the cluster average voltage and the average voltage of the module corresponding to the power after each shift, the target shift power of the battery module is determined, thereby achieving power balancing control. Furthermore, the cluster average voltage and the module average voltage are obtained based on charging data throughout the entire charging process and discharging data throughout the entire discharging process, rather than based on instantaneous data for power balancing control. This solves the problem of control reliability being affected by instantaneous data in the prior art, thus ensuring control reliability. Attached Figure Description

[0035] Figure 1 This is a flowchart of a power balancing control method provided in Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of a voltage change provided in Embodiment 1 of the present invention;

[0037] Figure 3 This is a flowchart of a power balancing control method provided in Embodiment 2 of the present invention;

[0038] Figure 4 This is a schematic diagram of voltage fitting provided in Embodiment 2 of the present invention;

[0039] Figure 5 This is a structural block diagram of a power balancing control device provided in Embodiment 3 of the present invention. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0041] Example 1

[0042] Figure 1This is a flowchart of a power balancing control method provided in Embodiment 1 of the present invention. This embodiment can be applied to power balancing control of each battery module in a battery cluster. The method can be executed by a power balancing control device, which can be integrated into the controller of the power management system. The controller can be implemented in software and / or hardware. The method specifically includes the following steps:

[0043] Step 110: Obtain charging and discharging data of the target battery cluster, which includes multiple battery modules connected in series.

[0044] The charging data includes the real-time charge level of the target battery cluster and the real-time voltage of each battery module during the charging process. The discharging data includes the real-time charge level of the target battery cluster and the real-time voltage of each battery module during the discharging process. The power management system includes a data acquisition module that collects the real-time charge level of the target battery cluster and the real-time voltage of each battery module. The controller is electrically connected to the acquisition module to obtain the charging and discharging data of the target battery cluster.

[0045] Step 120: Based on the charging and discharging data, determine the target power range, the cluster average voltage, and the module average voltage at different power levels within the target power range.

[0046] Specifically, the minimum value of the target power range is greater than the minimum power value in the charging and discharging data, and the maximum value of the target power range is less than the maximum power value in the charging and discharging data. Within the target power range, the cluster average voltage at a certain power level is the ratio of the sum of the voltages of all battery modules at that power level to the number of battery modules. Similarly, within the target power range, the module average voltage at a certain power level is the ratio of the sum of the voltages of all individual cells in that battery module to the number of individual cells in that battery module.

[0047] For example, Figure 2 This is a schematic diagram of a voltage change provided in Embodiment 1 of the present invention. (Reference) Figure 2 During the charging and discharging stages, the voltage changes of individual battery modules within the same battery cluster with varying ampere-hours (AHs), i.e., charge (hereinafter referred to as characteristic curves), exhibit a high degree of similarity. Within a certain error range, by appropriately shifting the average voltage data sequence of any battery module by an AH, the cluster average voltage data can be obtained. Visually, this can be represented as follows: after horizontally shifting the curves according to a certain AH, the voltage change trends of the two voltage curves under the same AH are consistent, indicating optimal linear correlation. In the same charging and discharging process, the voltage curves of the battery modules have an optimal AH shift, at which the average voltage of the battery module most closely matches the cluster average voltage trend.

[0048] Step 130: Based on the preset offset step size, the power corresponding to the module average voltage is offset successively to obtain the module average voltage corresponding to the power after each offset.

[0049] For example, the preset offset step size is between 0.02% and 0.1% of the rated capacity of the battery module. In the range of -5% to 5% of the rated capacity of the battery module, the preset offset step size is used to traverse the range to obtain the average voltage of the module corresponding to the power after each offset.

[0050] Step 140: Fit the cluster average voltage and the module average voltage corresponding to the power after each offset to determine the target offset power of the battery module, so as to perform power balance control based on the target offset power.

[0051] Specifically, the average voltage of the cluster and the average voltage of the module corresponding to the amount of electricity after each offset are fitted, such as by linear fitting, to obtain the correlation coefficient between the fitted average voltage of the cluster and the average voltage of the module. The target offset amount of the battery module is determined according to the magnitude of the correlation coefficient. For example, the difference in amount of electricity before and after the offset corresponding to the largest correlation coefficient in each offset is taken as the target offset amount of electricity, so as to control the battery module to transmit the target offset amount of electricity and achieve power balance.

[0052] It should be noted that the specific value of the preset offset step size can be determined according to actual control requirements, and is not limited here.

[0053] The power balancing control method provided in this embodiment obtains the module average voltage corresponding to the average voltage of the module after each shift by successively shifting the average voltage of the module. By fitting the cluster average voltage and the module average voltage corresponding to the average voltage of the module after each shift, the target shifted power of the battery module is determined, thereby achieving power balancing control. Furthermore, the cluster average voltage and the module average voltage are obtained based on the charging data of the entire charging process and the discharging data of the entire discharging process, rather than based on instantaneous data for power balancing control. This solves the problem of control reliability being affected by instantaneous data in the prior art, thus ensuring control reliability.

[0054] Example 2

[0055] Figure 3 This is a flowchart of a power balancing control method provided in Embodiment 2 of the present invention. This embodiment can be applied to power balancing control of each battery module in a battery cluster, etc. The method can be executed by a power balancing control device, which can be integrated into the controller of the power management system. The controller can be implemented in software and / or hardware. The method specifically includes the following steps:

[0056] Step 210: Obtain charging and discharging data of the target battery cluster, which includes multiple battery modules connected in series.

[0057] The charging and discharging data can be the charging data after multiple charging cycles and the discharging data after multiple discharging cycles of the target battery cluster. The charging and discharging data respectively include the real-time current of the target battery cluster during charging and discharging. After acquiring the charging and discharging data, the magnitude and changes of the current during a single charging / discharging process are filtered. If the total current value during the entire charging / discharging process is less than a threshold A (e.g., A is 0.2C, where C is the charging / discharging rate), or if the difference between the maximum and minimum current during the entire charging / discharging process is greater than B (e.g., B is 0.1C), then the charging / discharging data for that entire process is filtered out. This restricts the operating conditions of the target battery cluster to normal charging and discharging behavior, preventing unstable current conditions from affecting the accuracy of subsequent equalization control.

[0058] Furthermore, based on the charging / discharging data obtained through the above screening, the relative ampere-hours (Ahs) at the starting point of the data are marked as 0, and the Ahs are accumulated frame by frame. During charging, the relative Ahs continuously increases; during discharging, the relative Ahs continuously decreases. After the Ahs integration is completed, some statistics can be directly obtained, including the maximum relative Ahs Q during the process. max Minimum relative ampere-hour quantity Q min The change in ampere-hours Q throughout the entire process Delta Regarding the charging process, Q min Q is 0 max Q represents the relative ampere-hours at the end of charging, and for the discharging process, Q represents... min Q represents the relative ampere-hours at the end of the discharge. max Q is 0 Delta For Q max With Q min The difference. Furthermore, to ensure the effectiveness of power balance control, a sufficiently long charge / discharge range is required for a single charge / discharge process; that is, the change in ampere-hour needs to be greater than a certain threshold, which is set as C, and C takes the value Q. Cap 30%, Q Cap The nominal capacity is the rated capacity mentioned above. By using the above screening criteria, the target battery cluster is ensured to undergo continuous charging and discharging for a relatively long period, guaranteeing that the target battery cluster enters a stable phase and making the obtained data more representative.

[0059] Step 220: Based on the charging and discharging data, determine the target power range, the cluster average voltage, and the module average voltage at different power levels within the target power range.

[0060] Specifically, the battery module includes multiple individual cells connected in series. The charging and discharging data include the real-time voltage of each individual cell and the real-time charge of the target battery cluster. The sum of the real-time voltages of the individual cells in the target battery cluster is used as the cluster average voltage, and the sum of the real-time voltages of the individual cells in the battery module is used as the module average voltage.

[0061] Furthermore, the battery module voltage is affected by polarization. Insufficient polarization at the beginning of charging causes significant voltage fluctuations, which can introduce unpredictable errors. Similarly, at the end of charging or discharging, the battery reaches the charging and discharging ends, resulting in significant voltage curve changes, which can also lead to unpredictable errors. Therefore, to avoid the influence of the data at these two ends, the data in the middle segment of the process, i.e., the target battery capacity range, is selected according to the following criteria:

[0062]

[0063] Among them, Data Q This represents the relative ampere-hour value corresponding to any frame of data in this process. This process removes some data from the beginning and near-end of the charging / discharging process, retaining only the stable intermediate portion. Within this portion, i.e., the target charge range, the cluster average voltage and module average voltage are calculated for different ampere-hour values ​​(i.e., different charge levels), resulting in the cluster average voltage change sequence V for this charging / discharging process. cluster and the module average voltage change sequence V module And the relative change in ampere-hours, Q. Pairing the sequences yields two sets of data pairs (Q, V). cluster (Q, V) module These are denoted as P1 and P2, respectively. P1 reflects the change of cluster average voltage with relative ampere-hours, and P2 reflects the change of module average voltage with relative ampere-hours.

[0064] Step 230: Based on the preset offset step size, the power corresponding to the module average voltage is offset successively to obtain the module average voltage corresponding to the power after each offset.

[0065] Specifically, if there is no corresponding average module voltage after the offset, the average module voltage corresponding to the offset is determined by interpolation; if the offset of multiple times results in the offset of the power exceeding the target power range, the average module voltage corresponding to the power exceeding the target power range is deleted.

[0066] For example, using Q Cap -5% to 5% is used as the search range for the offset in ampere-hours. This range is traversed according to a preset step size I, and the effects of different offsets are compared and evaluated. The value of I ranges from Q.Cap The offset is between 0.02% and 0.1%. Record the offset as Q for each evaluation. offset Generate set data pairs (Q, V) sequences. cluster V module ), denoted as P3, the generation process is as follows: for any data pair (Q) in P3 n V cluster_n V module_n ), Q n V is the nth value of the relative ampere-hour data sequence Q mentioned above; cluster_n For P1, when the relative ampere-hour is equal to Q n V corresponding to time cluster Value; V module_n For P2, when the relative ampere-hour is equal to Q n +Q offset When, the corresponding V module Value. When there is no corresponding V in P2. module When calculating the value, the following processing is required: If Q n +Q offset Within sequence Q, statistical methods such as linear interpolation can be used to analyze V. module Make an estimate; if Q+Q offset If the data pair exceeds the boundary of sequence Q (greater than the maximum value of Q or less than the minimum value of Q), it is directly removed from P3. Then, Q is deleted from P3, thus completing the data pair sequence (V) of the offset module average voltage and the original cluster average voltage. cluster V module The construction of ) is denoted as P4.

[0067] Step 240: Perform linear fitting on the cluster average voltage and the module average voltage corresponding to the charge after each offset, and determine the correlation coefficient between the fitted cluster average voltage and the module average voltage corresponding to each offset.

[0068] For example, V in P4 cluster Let x be the independent variable and V be the independent variable. module Perform a linear fit model for the dependent variable y, and calculate the coefficient of determination R corresponding to the fit result. 2 That is, the correlation coefficient mentioned above. Among them, y i Let i be the i-th true value in the dependent variable. This corresponds to the i-th predicted value of the fitting result. R is the average of the true values. 2 The larger the value (maximum value is 1), the smaller the difference between the linear fitting result and the true value, the better the fitting effect, that is, the stronger the linear relationship between the independent variable and the dependent variable. Figure 4 This is a schematic diagram of voltage fitting provided in Embodiment 2 of the present invention, for reference. Figure 2 and Figure 4 ,like Figure 2 If two curves in a graph show similar trends under the same dependent variable, then the greater the linear correlation between them, the stronger the correlation. Therefore, the coefficient of determination R0 is used to determine the correlation. 2 Assess the correlation between the two. For example... Figure 4 As shown, the determination coefficient R 2 The similarity between the cluster average voltage and the average module voltage after offset is evaluated to determine the optimal ampere-hour offset, i.e., the target offset amount. When the horizontal ampere-hour difference between the two curves disappears after offset, leaving only the vertical difference, the voltage difference between the corresponding data sequences of the two curves at the same ampere-hour is close to a constant value. That is, at this time, the linear relationship between the average module voltage and the cluster average voltage after offset is the strongest, and the R-squared value of the linear fitting result is the highest. 2 The maximum value can be used to evaluate the offset effect and finally convert it into the corresponding equalization strategy.

[0069] Step 250: Determine the target offset capacity of the battery module based on the correlation coefficients corresponding to each offset.

[0070] Specifically, based on the correlation coefficients corresponding to each offset, the largest correlation coefficient among all offsets is determined; the difference between the offset battery capacity corresponding to the largest correlation coefficient and the battery capacity at offset zero is calculated, and this difference is used as the target offset battery capacity for the battery module. If the R obtained in this case... 2 The value is the maximum obtained from all past counts, and the current ampere-hour offset Q is calculated. offset Let it be Q best To achieve different ampere-hour offsets Q for the same battery module offset Through fitting evaluation, the ampere-hour offset Q corresponding to the highest linear correlation between cluster average voltage and module average voltage was finally determined. best .

[0071] Step 260: Based on the target offset, control the battery modules in the target battery cluster with a target offset less than zero to transfer energy to the battery modules with a target offset greater than zero.

[0072] Specifically, for each battery module Q best If Q best If the value is greater than 0, the battery module's charge level is lower than the average. Other modules are then controlled to transmit a value of Q to this battery module. best The amount of electricity, if Q best If the value is less than 0, the battery module's charge level is higher than the average, and the system controls the battery module to transfer Q values ​​to other modules. best The energy allows the battery modules in the battery cluster to reach a balanced state of charge.

[0073] It should be noted that the specific values ​​of each parameter in this embodiment can be determined according to actual control requirements, and are not limited here.

[0074] The power balancing control method provided in this embodiment determines the correlation coefficient between the fitted cluster average voltage and the module average voltage corresponding to the power level after each offset by performing linear fitting on the cluster average voltage and the module average voltage corresponding to each offset. Based on the correlation coefficient corresponding to each offset, the target offset power level of the battery module is determined, and the battery modules in the target battery cluster with a target offset of less than zero are controlled to transfer energy to the battery modules with a target offset of greater than zero, thereby achieving power balancing control. Furthermore, the cluster average voltage and module average voltage are obtained based on charging data throughout the entire charging process and discharging data throughout the entire discharging process, rather than based on instantaneous data for power balancing control. This solves the problem of control reliability being affected by instantaneous data in the prior art, thus ensuring control reliability.

[0075] Example 3

[0076] Figure 5 This is a structural block diagram of a power balancing control device provided in Embodiment 3 of the present invention. (Reference) Figure 5 The control device includes: a data acquisition module 310, a voltage determination module 320, a power offset module 330, and a power equalization control module 340. The data acquisition module 310 acquires charging and discharging data of the target battery cluster, which includes multiple battery modules connected in series. The voltage determination module 320 determines the target power range, the cluster average voltage, and the module average voltage at different power levels within the target power range based on the charging and discharging data. The power offset module 330 successively offsets the power corresponding to the module average voltage based on a preset offset step size, obtaining the module average voltage corresponding to the power after each offset. The power equalization control module 340 fits the cluster average voltage and the module average voltage corresponding to the power after each offset to determine the target offset power of the battery module, and performs power equalization control based on the target offset power.

[0077] Based on the above implementation method, the equalization control module 340 includes:

[0078] The coefficient determination unit is used to perform linear fitting on the cluster average voltage and the module average voltage corresponding to the power after each offset, and to determine the correlation coefficient between the fitted cluster average voltage and the module average voltage corresponding to each offset.

[0079] The power determination unit is used to determine the target offset power of the battery module based on the correlation coefficients corresponding to each offset.

[0080] In one embodiment, the above-mentioned power determination unit includes:

[0081] The coefficient determination sub-unit is used to determine the largest correlation coefficient in each offset based on the correlation coefficient corresponding to each offset.

[0082] The difference determination sub-unit is used to calculate the difference between the energy level after the offset corresponding to the largest correlation coefficient in each offset and the energy level at offset zero.

[0083] The battery level determination subunit is used to use the difference as the target offset battery level of the battery module.

[0084] Optionally, the above-mentioned equalization control module 340 includes:

[0085] Transmission control unit; used to control the transmission of energy from battery modules with a target offset less than zero to battery modules with a target offset greater than zero in the target battery cluster, based on the target offset.

[0086] Optionally, both charging and discharging data include the real-time voltage of each individual cell and the real-time charge level of the target battery cluster; the voltage determination module 320 includes:

[0087] Cluster average voltage determination unit; used to take the sum of the real-time voltages of each individual cell in the target battery cluster as the ratio of the total number of individual cells in the target battery cluster as the cluster average voltage;

[0088] The module average voltage determination unit is used to determine the module average voltage by taking the sum of the real-time voltages of each individual cell in the battery module as the ratio of the number of individual cells in the battery module.

[0089] Optionally, the power offset module 330 includes:

[0090] Voltage determination unit; used to determine the average module voltage corresponding to the offset power using interpolation if there is no corresponding average module voltage after the offset power.

[0091] Voltage deletion unit; used to delete the module average voltage corresponding to the power exceeding the target power range if the power exceeds the target power range after multiple offsets.

[0092] This embodiment also provides a power management system, including a data acquisition module and a controller. The data acquisition module is electrically connected to the controller, and the control device as described in any embodiment of the present invention is integrated into the controller. The controller is used for power balancing control; the specific control process can be referred to the above embodiments and will not be repeated here.

[0093] Optionally, the acquisition module corresponds one-to-one with each battery module in the target battery cluster. The acquisition module is used to collect charging and discharging data of the corresponding battery module. Specifically, the acquisition module transmits the collected data to the controller, so that the controller can perform power balancing control based on the data transmitted by the acquisition module.

[0094] The power balancing control device and power management system provided in this embodiment belong to the same inventive concept as the power balancing control method provided in any embodiment of the present invention, and have corresponding beneficial effects. For technical details not covered in this embodiment, please refer to the power balancing control method provided in any embodiment of the present invention.

[0095] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A power equalization control method, characterized in that, The method comprises: obtaining charging data and discharging data of a target battery cluster, the target battery cluster comprising a plurality of battery modules connected in series; determining a target power range and cluster average voltage and module average voltage at different power levels within the target power range according to the charging data and the discharging data; based on a preset offset step, offsetting the power corresponding to the module average voltage successively to obtain the module average voltage corresponding to the power after each offset; fitting the cluster average voltage and the module average voltage corresponding to the power after each offset to determine a target offset power of the battery module, so as to perform power balancing control according to the target offset power.

2. The control method according to claim 1, characterized by, The fitting of the cluster average voltage and the module average voltage corresponding to the power after each offset to determine the target offset power of the battery module comprises: linearly fitting the cluster average voltage and the module average voltage corresponding to the power after each offset to determine the correlation coefficient of the cluster average voltage and the module average voltage after fitting corresponding to each offset; determining the target offset power of the battery module according to the correlation coefficient corresponding to each offset.

3. The control method according to claim 2, characterized by, The determination of the target offset power of the battery module according to the correlation coefficient corresponding to each offset comprises: determining the maximum correlation coefficient in the offsets according to the correlation coefficient corresponding to each offset; determining the difference value by subtracting the power after the offset corresponding to the maximum correlation coefficient from the power after zero offset; taking the difference value as the target offset power of the battery module.

4. The control method according to claim 1, characterized by, The power balancing control according to the target offset power comprises: controlling the battery module with a target offset power less than zero in the target battery cluster to transfer energy to the battery module with a target offset power greater than zero.

5. The control method according to claim 1, characterized by, The battery module comprises a plurality of single batteries connected in series, and the charging data and the discharging data both comprise real-time voltages of each single battery and real-time power of the target battery cluster. The determination of the target power range and the cluster average voltage and the module average voltage at different power levels within the target power range according to the charging data and the discharging data comprises: taking the ratio of the sum of the real-time voltages of each single battery in the target battery cluster to the total number of single batteries included in the target battery cluster as the cluster average voltage; taking the ratio of the sum of the real-time voltages of each single battery in the battery module to the number of single batteries included in the battery module as the module average voltage.

6. The control method according to claim 1, characterized by, The offsetting of the power corresponding to the module average voltage successively based on a preset offset step to obtain the module average voltage corresponding to the power after each offset comprises: if there is no module average voltage corresponding to the power after offset, an interpolation method is used to determine the module average voltage corresponding to the power after offset; if the power after multiple offsets exceeds the target power range, the module average voltage corresponding to the power exceeding the target power range is deleted.

7. The control method according to claim 1, characterized by, The preset offset step is between 0.02% and 0.1% of the rated capacity of the battery module.

8. An electric power equalization control device, characterized by comprising: The method comprises: The data acquisition module is configured to acquire charging data and discharging data of a target battery cluster, the target battery cluster comprising a plurality of battery modules connected in series; The voltage determination module is configured to determine a target power range, cluster average voltages at different powers within the target power range, and module average voltages according to the charging data and the discharging data; The power offset module is configured to offset the power corresponding to the module average voltages by a preset offset step to obtain the module average voltages corresponding to the powers after each offset; The equalization control module is configured to fit the cluster average voltages and the module average voltages corresponding to the powers after each offset to determine a target offset power of the battery modules, and to perform power equalization control according to the target offset power.

9. A power management system, characterized by, The control device comprises a collection module and a controller, the collection module is electrically connected with the controller, and the control device as claimed in claim 8 is integrated in the controller.

10. The power management system of claim 9, wherein, The collection module corresponds to each battery module in the target battery cluster one by one, and the collection module is configured to collect charging data and discharging data of the corresponding battery module.

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