Power battery equalization control method and system, electric vehicle, device and medium

Abstract

The application provides a power battery equalization control method and system, an electric vehicle, equipment and a medium, and relates to the technical field of battery management. The method is applied to a control system in an active equalization system of an electric vehicle, and includes: obtaining voltage extreme values and reference values in voltage data of a plurality of battery cells contained in a power battery at a target time during charging or discharging of the power battery in the electric vehicle; when the voltage extreme values and the reference values satisfy a preset equalization condition, taking a battery cell with the voltage extreme value as a first battery cell, generating a switch closing instruction, and sending the switch closing instruction to a control end of a first equalization switch, so that energy of the first battery cell or energy of a second battery cell is transferred between the first battery cell and the second battery cell. The above-mentioned mode reduces the complexity of active equalization control, and thus improves the equalization effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery management, and in particular to a power battery equalization control method and system, an electric vehicle, equipment and a medium. BACKGROUND

[0002] As the main tool for travel and transportation, pure electric vehicles have gradually penetrated into modern society, and the cruising range is one of the main technical parameters that users are concerned about, which is related to the charging / discharging capacity of the power battery. However, the power battery has a "bucket effect", that is, the maximum charging capacity and the maximum discharging capacity of the power battery are often closely related to the weakest cell: when charging, if one cell in the power battery is fully charged, the entire charging process will end; when discharging, if one cell in the power battery discharges to the minimum voltage, the discharging process will be terminated, thereby reducing the charging efficiency and the utilization rate of the discharging energy of the power battery, and greatly reducing the service life of the power battery. Therefore, it is particularly important to use a power battery equalization system in a pure electric vehicle.

[0003] The passive equalization system commonly existing at present balances the pressure difference between each cell through resistance heat dissipation, which easily causes a large amount of energy loss of the power battery. The active equalization system existing at present can reduce the energy difference between cells in the charging / discharging process of the power battery through energy transfer between cells, but has the defects of high active equalization cost and immature technology.

[0004] Correspondingly, there is a need in the art to study a new active equalization technical solution to solve the above problems. SUMMARY

[0005] The present application provides a power battery equalization control method, system, electric vehicle, equipment and medium to solve the technical problems of late equalization and poor equalization effect caused by high active equalization control complexity in the prior art.

[0006] According to a first aspect of the present application, a power battery equalization control method is provided, which is applied to a control system in an active equalization system of an electric vehicle, and includes:

[0007] In the charging or discharging process of the power battery in the electric vehicle, the voltage extreme value and the reference value in the voltage data of a plurality of battery cells contained in the power battery at a target time are obtained;

[0008] When the voltage extreme value and the reference value meet the preset equalization condition, the battery cell with the voltage extreme value is used as the first battery cell, a switch closing command is generated, and the switch closing command is sent to the control terminal of the first equalization switch so that the energy of the first battery cell or the energy of the second battery cell is transferred between the first battery cell and the second battery cell.

[0009] The first battery cell is connected in series with the second battery cell via a first branch. During charging, the second battery cell refers to the battery cell with the lower voltage value among the battery cells adjacent to the first battery cell, and during discharging, the second battery cell refers to the battery cell with the higher voltage value among the battery cells adjacent to the first battery cell. The first equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the second battery cell, and the second branch is another branch different from the first branch.

[0010] Furthermore, during the charging process of the power battery in the electric vehicle, the voltage extreme value is the maximum voltage value, and the reference value is the average voltage value;

[0011] The voltage extreme value and reference value satisfy the preset equalization conditions, including:

[0012] The difference between the maximum voltage and the average voltage is greater than or equal to a preset voltage difference threshold.

[0013] During the discharge process of the power battery in the electric vehicle, the voltage extreme value is the minimum voltage value, and the reference value is the discharge termination threshold.

[0014] The voltage extreme value and reference value satisfy the preset equalization conditions, including:

[0015] The minimum voltage value is less than or equal to the discharge termination threshold.

[0016] Furthermore, after sending the switch closing command to the control terminal of the first equalization switch, the method further includes:

[0017] Determine whether the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold to obtain a first determination result;

[0018] Based on the first judgment result, the corresponding operation is performed.

[0019] Further, the step of performing the corresponding operation based on the first determination result includes:

[0020] When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold, it is determined whether the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than the preset voltage difference threshold, and a second judgment result is obtained; wherein, the third battery cell during the charging process refers to the battery cell with a larger voltage value among the battery cells adjacent to the first battery cell.

[0021] When the second determination result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold, a switch disconnection command is sent to the control terminal of the first equalization switch so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell.

[0022] Furthermore, after determining whether the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold, and obtaining a second determination result, the method further includes:

[0023] When the second judgment result indicates that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is not less than a preset voltage difference threshold, a switch closing command is sent to the control terminal of the second equalization switch; wherein, the second equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the third battery cell;

[0024] When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold, and the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold, corresponding switch disconnection commands are sent to the control terminals of the first equalization switch and the second equalization switch, respectively, so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell and between the first battery cell and the third battery cell.

[0025] Furthermore, the active balancing module also includes a filtering circuit, or includes a filtering circuit and a stabilizing circuit connected to each other, so that the energy of the first battery cell or the second battery cell is transferred between the first battery cell and the second battery cell through the filtering effect of the filtering circuit, or through the filtering effect of the filtering circuit and the stabilizing effect of the stabilizing circuit.

[0026] According to a second aspect of this application, an active balancing system is provided, comprising a control system, a computing system, and a battery system interconnected with each other; wherein the battery system includes a power battery and a plurality of active balancing modules, wherein the power battery includes a plurality of battery cells, and an active balancing module is provided on a second branch between two adjacent battery cells, the active balancing module including a balancing switch.

[0027] According to a third aspect of this application, an electric vehicle is provided, including a vehicle control system and an active balancing system.

[0028] According to a fourth aspect of this application, an electronic device is provided, comprising: at least one processor and a memory;

[0029] The memory stores computer-executed instructions;

[0030] The at least one processor executes computer execution instructions stored in the memory, causing the at least one processor to perform the method described in the first aspect above.

[0031] According to a fifth aspect of this application, a computer-readable storage medium is provided, wherein computer-executable instructions are stored therein, which, when executed by a processor, are used to implement the method described in the first aspect above.

[0032] According to a sixth aspect of this application, a computer program product is provided, comprising a computer program that, when executed by a processor, implements the method described in the first aspect.

[0033] This application provides a power battery balancing control method, system, electric vehicle, device, and medium, comprising: during the charging or discharging process of the power battery in an electric vehicle, acquiring the voltage extreme value and reference value of the voltage data of multiple battery cells contained in the power battery at a target time; when the voltage extreme value and reference value meet a preset balancing condition, selecting the battery cell with the voltage extreme value as the first battery cell, generating a switch closing command, and sending the switch closing command to the control terminal of the first balancing switch, so that the energy of the first battery cell or the energy of the second battery cell is transferred between the first battery cell and the second battery cell; wherein, the first battery cell is connected in series with the second battery cell through a first branch; the second battery cell during the charging process refers to the battery cell with a smaller voltage value among the battery cells adjacent to the first battery cell, and the second battery cell during the discharging process refers to the battery cell with a larger voltage value among the battery cells adjacent to the first battery cell; the first balancing switch is the balancing switch in the active balancing module located on the second branch between the first battery cell and the second battery cell, and the second branch is another branch different from the first branch.

[0034] This application achieves equalization control through energy transfer between adjacent battery cells. Since the distance between adjacent battery cells is the shortest, this application can greatly reduce energy loss and provides an active equalization process between two adjacent battery cells, which can guarantee the equalization effect of this application. Since this application does not require complex equalization design between all battery cells, it has the advantages of reducing control complexity, helping to reduce costs, improving equalization effect and equalization efficiency, and thus has high practical value in power batteries.

[0035] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0036] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 This is a schematic diagram of an active balancing system provided in an embodiment of this application;

[0038] Figure 2 A flowchart illustrating a power battery balancing control method provided in an embodiment of this application;

[0039] Figure 3 A schematic flowchart of another power battery balancing control method provided in an embodiment of this application;

[0040] Figure 4 A schematic diagram of an electric vehicle provided as an embodiment of this application;

[0041] Figure 5 This is a schematic diagram of the structure of a power battery balancing control device provided in an embodiment of this application;

[0042] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0043] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present application, the technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0045] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0046] Currently prevalent passive balancing systems balance the voltage difference between individual cells by dissipating heat through resistance, which easily leads to significant energy loss in the power battery. While existing active balancing systems can reduce energy differences between cells during charging and discharging by transferring energy between them, they suffer from drawbacks such as high cost and immature technology.

[0047] To address the aforementioned technical problems, the overall inventive concept of this application is to provide an active balancing system applied in the field of battery management technology to improve the utilization rate of battery energy and thereby increase the driving range of electric vehicles.

[0048] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0049] Example 1:

[0050] Figure 1 This is a schematic diagram of an active balancing system provided in an embodiment of this application. The technical solution of this embodiment is applicable to the charging / discharging process of a power battery. Figure 1 As shown, the active balancing system includes an interconnected control system (Controller_system) 1, a computing system (Calculator_system) 2, and a battery system (Battery_system) 3. The battery system 3 includes a power battery 31 and multiple active balancing modules 32. The power battery 31 includes multiple battery cells 311, and an active balancing module 32 is located on the second branch between two adjacent battery cells 311. The active balancing module 32 includes a balancing switch 321.

[0051] It should be understood that the aforementioned power battery 31 can refer to a Simulink power battery or a real battery in actual applications (e.g., lithium iron phosphate battery, ternary lithium battery, etc.). Therefore, the active balancing system provided in this application embodiment can be an active balancing system based on a Simulink power battery.

[0052] It should be understood that battery cell 311, also known as cell module, can be simply referred to as cell. The structure of multiple battery cells 311 is similar to that of an actual power battery, meaning that the battery cells 311 are connected in series. Since the power battery 31 can refer to either a lithium iron phosphate battery or a ternary lithium battery, and the power battery 31 includes multiple battery cells 311, the voltage of a lithium iron phosphate battery cell 311 is generally between 2.0V and 3.6V, with a nominal voltage of 3.2V. This means that under stable conditions / during the entire driving process, the voltage of the battery cell 311 remains approximately 3.2 volts. The voltage of a ternary lithium battery cell 311 is generally between 2.5V and 4.2V.

[0053] Regarding the voltage range, the specific analysis is as follows: For the entire power battery 31, the voltage values ​​differ after it is fully charged and fully discharged. The same applies to any individual battery cell within it. During charging, there is a high-level termination charging voltage, meaning that once the battery is fully charged, charging stops. During discharging, there is a low-level termination discharging voltage (or discharge termination threshold), meaning that once the battery is completely discharged, the vehicle stops and ceases operation.

[0054] It should be understood that the active balancing module 32 performs active balancing processing based on the control signal received from the control system 1. This control signal may also be referred to as an external physical signal. If the external physical signal is greater than the switching threshold, the balancing switch 321 closes; otherwise, the balancing switch 321 opens. The balancing switch 321 may also be referred to as a control switch, a condition selection switch, or a power battery active balancing switch. The balancing switch 321 is in the open state by default. When the battery cells 311 on both sides need to be balanced, the balancing switch 321 is closed under the control of the control system 1. Since an active balancing module 32 is provided on the second branch between two adjacent battery cells 311, and the active balancing module 32 includes the balancing switch 321, there is a balancing switch 321 on each of the second branches between two adjacent battery cells 311. Furthermore, the states (closed / open) of all balancing switches 321 included in the battery system 3 can be represented using a state matrix.

[0055] Optionally, in addition to the power battery 31 and multiple active balancing modules 32, the battery system 3 also includes a cell voltage measurement module.

[0056] In the embodiments of this application, the functions of each component are analyzed as follows:

[0057] The battery system 3 is used to collect voltage data of the battery cells during the charging / discharging process of the power battery 31, and upload the voltage data of multiple battery cells 311 at a target time to the computing system 2 and the control system 1 respectively. The above voltage data is also referred to as voltage values ​​or voltage values ​​(Cell_voltages).

[0058] Specifically, each cell voltage measurement module in the battery system 3 is placed at both ends of each cell 311. The battery system 3 converts the voltage values ​​measured by each cell voltage measurement module into Simulink signals by using commands in Simulink, and then combines them into a vector or multi-dimensional array voltage signal, which is then output to the control system 1 and the computing system 2.

[0059] The calculation system 2 calculates the voltage data to obtain the minimum voltage (Min_voltages), maximum voltage (Max_voltage), and average voltage (Aver_voltage), and sends the minimum voltage, maximum voltage, and average voltage to the control system 1.

[0060] Specifically, the calculation system 2 can use the maximum and minimum values ​​calculation module in Simulink to calculate the maximum voltage, minimum voltage, and average voltage based on the data measured by the cell voltage measurement module.

[0061] The control system 1 receives the voltage value uploaded by the battery system 3 and calculates the minimum, maximum, and average voltage values ​​uploaded by the system 2. Based on a preset intelligent control algorithm or strategy, it determines whether the voltage value of each battery cell 311 meets a preset equalization condition. When the preset equalization condition is met, it sends a control signal to the battery system 3 to control the opening / closing of the equalization switches 321 between all adjacent battery cells. It should be noted that the control system in this embodiment can control the opening / closing of all equalization switches 321 through the state matrix of a state machine. The control signal, or control information, is a set of instructions for opening / closing all equalization switches 321.

[0062] The aforementioned preset intelligent control algorithm includes the various logical judgments described in Example 2, which will not be repeated here. The aforementioned control strategy includes when to perform equalization processing, energy transfer, and other related aspects.

[0063] Optionally, in the active balancing system, the computing system 2 and the control system 1 can be deployed independently or integrated. Independent deployment has advantages such as high security and ease of secondary development, while integrated deployment has advantages such as strong scalability, easy implementation and high availability.

[0064] The main technical point of this application embodiment is that adjacent battery cells in the power battery 31 are connected in series. In this embodiment, during each control operation, the battery cell with the extreme voltage value is used as the first battery cell, and the battery cells on both sides of it are determined as the second and third battery cells according to the charging and discharging type. Then, these three battery cells are used as a group of components to be balanced for balancing. Even if there are many battery cells in the power battery 31, it does not affect the determination of these three battery cells. For example, if there are 100 battery cells, and the 45th battery cell is the first battery cell, this group of battery cells includes the 44th, 45th, and 46th battery cells. For each group of battery cells, whether the battery cells on both sides and the middle battery cell transfer energy is determined by the closed / open state of the two balancing switches 321 located between the three battery cells in the active balancing module 32.

[0065] It should be noted that the active balancing process during the charging process of the power battery in an electric vehicle differs from the active balancing process during the discharging process. Specifically, during the charging process, this embodiment uses the battery cell with the smaller voltage value adjacent to the first battery cell as the second battery cell, thereby transferring the energy of the first battery cell between the first and second battery cells. During the discharging process, this embodiment uses the battery cell with the larger voltage value adjacent to the first battery cell as the second battery cell, thereby transferring the energy of the second battery cell between the second and first battery cells. The specific description process is given in Embodiment 2 below, and will not be repeated here.

[0066] In existing technologies, batteries stop charging when one cell reaches a high-level termination charging voltage, and stop discharging when one cell falls below a low-level termination discharging voltage. This results in incomplete charging and discharging, meaning the battery is not truly fully charged. In contrast, the active balancing system provided in this application maximizes energy replenishment and release during charging and discharging by controlling energy transfer between battery cells, thereby improving battery energy utilization and increasing the driving range of electric vehicles.

[0067] The embodiments of this application have the following advantages: equalization control is achieved through energy transfer between adjacent battery cells. Since the distance between adjacent battery cells is the shortest, the embodiments of this application can greatly reduce energy loss. Furthermore, an active equalization process is provided between two adjacent battery cells, which can guarantee the equalization effect of the embodiments of this application. Since the embodiments of this application do not require complex equalization design between all battery cells, they have the advantages of reducing control complexity, helping to reduce costs, improving equalization effect and efficiency, and thus have high practical value in power batteries.

[0068] In one possible implementation, the active balancing module 32 further includes a filter circuit, or includes a filter circuit and a stabilizing circuit connected to each other, so that the energy of the power battery 31 is transferred between two adjacent battery cells 311 through the filtering effect of the filter circuit, or through the filtering effect of the filter circuit and the stabilizing effect of the stabilizing circuit.

[0069] In this embodiment, the filtering circuit may include a capacitor, and the stabilizing circuit may include an inductor. This embodiment does not impose specific limitations on the specific structure of the filtering and stabilizing circuits. The active balancing module 32 refers to a module composed of all balancing switches 321 and filtering circuits, etc., and whether the energy of each group of battery cells 311 needs to be transferred is controlled by the corresponding balancing switch 321 in the active balancing module 32. The active balancing module 32 connects a small-capacity capacitor and inductor in parallel on the second branch between the battery cells 311. The purpose is to reduce energy surges and energy losses during energy transfer between the battery cells.

[0070] In summary, the active balancing system provided in this application embodiment can balance the voltage values ​​between battery cells by transferring energy during the charging / discharging process of the power battery, thereby extending the charging / discharging time, improving the utilization rate of battery energy, and thus increasing the driving range of electric vehicles.

[0071] Based on the above embodiments, the technical solution of this application will be described in more detail below with reference to several specific embodiments.

[0072] Example 2:

[0073] Figure 2 This is a flowchart illustrating a power battery balancing control method provided in an embodiment of this application. Figure 2 As shown, the method of this embodiment is applied to the control system of an active balancing system for an electric vehicle, and includes the following steps:

[0074] S10. During the charging or discharging process of the power battery in an electric vehicle, obtain the voltage extreme value and reference value of the voltage data of multiple battery cells contained in the power battery at the target time.

[0075] S20. When the voltage extreme value and the reference value meet the preset equalization conditions, the battery cell with the voltage extreme value is taken as the first battery cell, a switch closing command is generated, and a switch closing command is sent to the control terminal of the first equalization switch so that the energy of the first battery cell or the energy of the second battery cell is transferred between the first battery cell and the second battery cell; wherein, the first battery cell is connected in series with the second battery cell through the first branch; the second battery cell during the charging process refers to the battery cell with the smaller voltage value among the battery cells adjacent to the first battery cell, and the second battery cell during the discharging process refers to the battery cell with the larger voltage value among the battery cells adjacent to the first battery cell; the first equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the second battery cell, and the second branch is another branch different from the first branch.

[0076] This power battery balancing control method achieves balancing control through energy transfer between adjacent battery cells. Since the distance between adjacent battery cells is the shortest, this embodiment can greatly reduce energy loss and provides an active balancing process between two adjacent battery cells, which can guarantee the balancing effect of this application. Since this embodiment does not require complex balancing design between all battery cells, it has the advantages of reducing control complexity, helping to reduce costs, improving balancing effect and balancing efficiency, and thus has high practical value in power batteries.

[0077] In one possible implementation, during the charging process of the power battery in an electric vehicle, the voltage extreme value is the maximum voltage value, and the reference value is the average voltage value; then the voltage extreme value and the reference value satisfy a preset balance condition, including: the difference between the maximum voltage value and the average voltage value is greater than or equal to a preset voltage difference threshold.

[0078] In this application embodiment, the preset equalization condition, also known as the equalization start condition, can be the voltage value of the electric vehicle during driving, and the preset voltage difference threshold can be any value. This application embodiment does not specifically limit its specific value, including but not limited to: 1V, 0.8V, 0.5V, etc.

[0079] For example, during charging, the voltage of the 45th battery cell out of 100 battery cells at a certain moment is the highest voltage compared to the voltage values ​​of other battery cells at the same moment. Furthermore, the difference between this highest voltage and the average voltage is greater than or equal to a preset voltage difference threshold. If no equalization process is performed at this point, the electric vehicle will terminate the charging process, even though some battery cells in the entire power battery have not reached full capacity. To further increase the energy of these battery cells, this application provides a power battery equalization control method. This method transfers the energy of the 45th battery cell between the 45th and 44th battery cells, and / or between the 45th and 46th battery cells, thereby reducing the voltage value of the 45th battery cell. After the voltage value of the 45th battery cell is reduced, the difference between its voltage and the average voltage no longer meets the charging termination condition. When the energy of all battery cells has risen to approximately the threshold, for example, when the difference between the energy and the average voltage of the 46th and / or 44th battery cells is greater than or equal to the preset voltage difference threshold, charging is terminated.

[0080] During the discharge process of the power battery in an electric vehicle, the voltage extreme value is the voltage minimum value, and the reference value is the discharge termination threshold. The voltage extreme value and the reference value satisfy the preset equalization conditions, including: the voltage minimum value is less than or equal to the discharge termination threshold.

[0081] For example, during discharge, the voltage of the 45th battery cell out of 100 battery cells at a certain moment is the lowest compared to the voltages of other battery cells at the same moment, and this lowest voltage is less than or equal to the discharge termination threshold. If equalization is not performed at this point, the electric vehicle will soon operate at limited power or even stop. To extend the discharge time, this application provides a power battery equalization control method that transfers energy between the 46th and / or 44th battery cells to increase the voltage of the 45th battery cell. After the voltage of the 45th battery cell is increased, it no longer meets the discharge termination condition of being less than or equal to the discharge termination threshold. Discharge is terminated when the energy of all battery cells is nearly exhausted, for example, when the energy of the 46th and / or 44th battery cells is also less than or equal to the discharge termination threshold.

[0082] Therefore, this embodiment can reduce the difference between adjacent battery cells to a certain range, which is equivalent to keeping the voltage value of the entire power battery within a certain range, thus extending the power limit or parking time of the electric vehicle and increasing the driving range.

[0083] Furthermore, the above two preset equalization conditions are exemplary descriptions. In practice, the embodiments of this application do not specifically limit the setting of preset equalization conditions. For example, a preset equalization condition may refer to: the difference between the maximum voltage value and the minimum voltage value is greater than or equal to a preset voltage difference threshold. In the case of battery cell grouping, the preset equalization condition may refer to: the difference between all voltage values ​​in one group and the average voltage value is greater than or equal to a preset voltage difference threshold, and the difference between all voltage values ​​in another group and the average voltage value is less than a preset voltage difference threshold.

[0084] For example, if there are 60 battery cells divided into 20 groups, and the voltage difference between the three cells in the 10th group and the average voltage is greater than or equal to a preset voltage difference threshold, and the voltage difference between the three cells in the 11th group and the average voltage is less than the preset voltage difference threshold, and the voltage difference between the three cells in the 9th group and the average voltage is also less than the preset voltage difference threshold, then in this embodiment, the 10th group is determined as the first group; the average voltage values ​​of the three cells in the 9th and 11th groups are calculated respectively, and the two average values ​​are compared, and the group with the smaller average value is determined as the second group;

[0085] The balancing switch between the leftmost cell in the 10th group and the rightmost cell in the 9th group is closed first to balance the energy of the cells in the 10th group across groups, and then the energy of the three cells within each group is balanced. This embodiment of the application, through the combined effect of external and internal balancing, enables regular balancing control and improves the accuracy of balancing.

[0086] In one possible implementation, after sending a switch-closing command to the control terminal of the first equalizing switch, the method further includes:

[0087] S30. Determine whether the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold, and obtain the first judgment result.

[0088] S40. Based on the first judgment result, perform the corresponding operation.

[0089] The embodiments of this application can perform corresponding operation processing based on the first judgment result, ensuring the comprehensiveness of the scheme setting and thus improving the effectiveness of the balance.

[0090] In one possible implementation, step S40, based on the first judgment result, performs the corresponding operation processing, including the following steps:

[0091] S401. When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than the preset voltage difference threshold, determine whether the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than the preset voltage difference threshold, and obtain the second judgment result.

[0092] Among them, the third battery cell during the charging process refers to the battery cell with the larger voltage value among the battery cells adjacent to the first battery cell.

[0093] S402. When the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than the preset voltage difference threshold, a switch disconnection command is sent to the control terminal of the first equalization switch so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell.

[0094] In this embodiment of the application, when the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than the preset voltage difference threshold, it indicates that the closing of the switch ensures the balancing effect. Furthermore, judging the difference between the voltage value of the first battery cell and the voltage value of the third battery cell can further ensure the energy balance between adjacent battery cells. By executing the above process, on the one hand, the comprehensiveness of the scheme setting can be ensured, and on the other hand, the control complexity and balancing cost can be reduced.

[0095] In one possible implementation, after determining whether the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold in step S401, and obtaining a second determination result, the method further includes the following steps:

[0096] S403. When the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is not less than the preset voltage difference threshold, a switch closing command is sent to the control terminal of the second equalization switch; wherein, the second equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the third battery cell.

[0097] Step S404: When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than the preset voltage difference threshold, and the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than the preset voltage difference threshold, corresponding switch disconnection commands are sent to the control terminals of the first equalization switch and the second equalization switch, respectively, so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell and between the first battery cell and the third battery cell.

[0098] After balancing is completed, this embodiment of the application can ensure that all switches are disconnected in a timely manner when balancing is not required by controlling all switches, thereby reducing control complexity.

[0099] In one possible implementation, the active balancing module further includes a filtering circuit, or includes a filtering circuit and a stabilizing circuit connected to each other, so that the energy of the first battery cell or the second battery cell is transferred between the first battery cell and the second battery cell through the filtering effect of the filtering circuit, or through the filtering effect of the filtering circuit and the stabilizing effect of the stabilizing circuit.

[0100] The active balancing module connects a small-capacity capacitor and inductor in parallel on the second branch between the battery cells. The purpose is to reduce energy surges and energy losses when the energy of the battery cells is transferred.

[0101] Example 3:

[0102] Figure 3 This is a flowchart illustrating another power battery balancing control method provided in an embodiment of this application. Figure 3 As shown, this power battery balancing control method performs energy balancing control on the battery cells during the charging / discharging process of the power battery. This control strategy refers to an active balancing strategy. Taking the charging process of an electric vehicle as an example, in an electric vehicle, the default state of the active balancing system is the standby state (i.e., not activated). The following section combines... Figure 3 This paper provides a detailed explanation of the power battery balancing control method in the active balancing system.

[0103] S1. The battery system obtains the voltage values ​​of each cell from the battery model and transmits them to the control system and computing system in the form of vectors or multi-dimensional matrices. In step S1, data transmission can be performed according to the sampling frequency.

[0104] Before executing step S1, this embodiment may also receive a start equalization command (Balflg) from the vehicle control system (VCU). The start equalization command is also referred to as a power-on signal.

[0105] S2. The calculation system performs maximum and minimum value calculations based on the obtained voltage values ​​of each cell to obtain the maximum voltage value and the average voltage value. The cell with the maximum voltage value is selected as the first target cell. The two cells adjacent to the first target cell are sorted in order of voltage value from low to high and selected as the second and third targets cell, respectively.

[0106] It should be understood that the first target cell, the second target cell, and the third target cell correspond to the first battery cell, the second battery cell, and the third battery cell in Embodiment 2, respectively. The first target cell is the cell with the highest voltage. Among multiple cells, there is a maximum value, and the voltage value of the first target cell is compared with the average voltage. If the voltage difference between the average voltage and the first target cell is greater than a preset voltage difference threshold, equalization processing is performed, and then instructions such as opening / closing the switch are issued. After equalization processing, if the control system detects that the voltage difference between the first target cell and the third target cell is greater than or equal to the preset voltage difference threshold, then another equalization processing is required. Therefore, this embodiment is equivalent to grouping three cells together, determining the maximum voltage of a certain cell, and then equalizing the energy of the first target cell with the maximum voltage among adjacent cells. If further equalization is required, the equalization process is still performed in groups of three cells.

[0107] After steps S1 and S2 are completed, the control system determines whether the preset equalization condition has been met by logical judgment based on the voltage value, maximum voltage / minimum voltage value, and average voltage value of each cell. When the preset equalization condition is met, the active equalization process is started.

[0108] S3. The control system outputs a signal to close the switch between the first battery cell target and the second battery cell target, so that the switch between the first battery cell target and the second battery cell target is closed.

[0109] In this embodiment, the control system preferentially closes the switch between the first battery cell target and the second battery cell target, so that the energy of the first battery cell target is transferred to the second battery cell target after filtering and / or stabilization. If there is a need to close other switches subsequently, this embodiment can also close the switch between the first battery cell target and the third battery cell target in step S6.

[0110] In this embodiment, closing the corresponding switch during the active balancing process enables energy transfer. During charging, the preset balancing condition can be defined as receiving a power-on signal from the vehicle control system and the voltage difference between the maximum and average voltage values ​​being greater than or equal to a voltage difference threshold. During discharging, the preset balancing condition can be defined as receiving a power-on signal from the vehicle control system and the minimum voltage value being less than or equal to a discharge termination threshold. In this case, the corresponding active balancing process transfers energy from adjacent cells to the cell with the minimum voltage value. Additionally, in a parked state, the preset balancing condition can also refer to a manually triggered command. Therefore, this embodiment can set different preset balancing conditions for different scenarios; satisfying any preset balancing condition will initiate the corresponding active balancing process.

[0111] After step S3 is completed, the Simulink stateflow state machine can be used to continue the judgment and execute the following steps S4 to S6 until the active balancing process ends.

[0112] S4. Determine whether the voltage difference between the target voltage value of the first battery cell and the average voltage value is less than the voltage difference threshold; if yes, proceed to step S5; otherwise, continue to step S3.

[0113] S5. Determine whether the voltage difference between the first target cell voltage value and the third target cell voltage value is less than the voltage difference threshold; if not, proceed to step S6; if yes, disconnect all switches and end the active balancing process.

[0114] S6. Close the switch between the first battery cell target and the third battery cell target. After closing, continue to execute step S5.

[0115] In existing technologies, during the charging process, when one cell in the power battery is fully charged (i.e., the cell's voltage reaches its maximum value), the battery system directly shuts off the main switch of the power battery, ending the charging process. During the discharging process, when one cell's voltage reaches its minimum value (i.e., the aforementioned discharge termination threshold), the discharge process terminates. This results in reduced charging efficiency and energy utilization of the power battery. The power battery balancing control method provided in this application can effectively solve the above-mentioned technical problems and has the advantages of low cost and low complexity of active balancing control, thereby ensuring timely balancing and improving the balancing effect.

[0116] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

[0117] Example 4:

[0118] Figure 4 This is a schematic flowchart of an electric vehicle provided as an embodiment of this application. Figure 4 As shown, the electric vehicle includes a vehicle control system 10 and an active balancing system 20.

[0119] The electric vehicle provided in this embodiment includes an active balancing system 20 whose control system can be used to execute the power battery balancing control method provided in any of the above method embodiments. The implementation principle and technical effects are similar, and will not be elaborated here. Example 5:

[0120] Figure 5 This is a schematic diagram of a power battery balancing control device provided in an embodiment of this application. The device in this embodiment can be in software and / or hardware form. Figure 5 As shown, the power battery balancing control device provided in this embodiment includes: an acquisition module 51 and a generation and transmission module 52. Wherein:

[0121] The acquisition module 51 is used to acquire the voltage extreme value and reference value of the voltage data of multiple battery cells contained in the power battery at a target time during the charging or discharging process of the power battery in the electric vehicle.

[0122] The generation and transmission module 52 is used to, when the voltage extreme value and the reference value meet the preset equalization conditions, select the battery cell with the voltage extreme value as the first battery cell, generate a switch closing command, and send the switch closing command to the control terminal of the first equalization switch, so that the energy of the first battery cell or the energy of the second battery cell can be transferred between the first battery cell and the second battery cell; wherein, the first battery cell is connected in series with the second battery cell through a first branch; the second battery cell during the charging process refers to the battery cell with the smaller voltage value among the battery cells adjacent to the first battery cell, and the second battery cell during the discharging process refers to the battery cell with the larger voltage value among the battery cells adjacent to the first battery cell; the first equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the second battery cell, and the second branch is another branch different from the first branch.

[0123] In one possible implementation, during the charging process of the power battery in an electric vehicle, the voltage extreme value is the maximum voltage value, and the reference value is the average voltage value; then the voltage extreme value and the reference value satisfy a preset balance condition, including: the difference between the maximum voltage value and the average voltage value is greater than or equal to a preset voltage difference threshold.

[0124] During the discharge process of the power battery in an electric vehicle, the voltage extreme value is the voltage minimum value, and the reference value is the discharge termination threshold. The voltage extreme value and the reference value satisfy the preset equalization conditions, including: the voltage minimum value is less than or equal to the discharge termination threshold.

[0125] In one possible implementation, after sending a switch-closing command to the control terminal of the first equalization switch, the power battery equalization control device is further used to:

[0126] Determine whether the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold to obtain the first determination result.

[0127] Based on the first judgment result, the corresponding operation is performed.

[0128] In one possible implementation, the power battery balancing control device is also used for:

[0129] When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than the preset voltage difference threshold, it is determined whether the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than the preset voltage difference threshold, and a second judgment result is obtained; wherein, the third battery cell during the charging process refers to the battery cell with a larger voltage value among the battery cells adjacent to the first battery cell.

[0130] When the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than the preset voltage difference threshold, a switch disconnection command is sent to the control terminal of the first equalization switch so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell.

[0131] In one possible implementation, after determining whether the difference between the voltage values ​​of the first battery cell and the third battery cell is less than a preset voltage difference threshold, and obtaining a second determination result, the power battery balancing control device is further used to:

[0132] When the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is not less than the preset voltage difference threshold, a switch closing command is sent to the control terminal of the second equalization switch; wherein, the second equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the third battery cell.

[0133] When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold, and the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold, corresponding switch disconnection commands are sent to the control terminals of the first equalization switch and the second equalization switch, respectively, so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell and between the first battery cell and the third battery cell.

[0134] In one possible implementation, the active balancing module further includes a filtering circuit, or includes a filtering circuit and a stabilizing circuit connected to each other, so that the energy of the first battery cell or the second battery cell is transferred between the first battery cell and the second battery cell through the filtering effect of the filtering circuit, or through the filtering effect of the filtering circuit and the stabilizing effect of the stabilizing circuit.

[0135] The power battery balancing control device provided in this embodiment can be used to execute the power battery balancing control method provided in any of the above method embodiments. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0136] It should be noted that the user information and data involved in this application (including but not limited to data used for analysis, stored data, and displayed data) are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use, and processing of the relevant data must comply with the relevant laws, regulations, and standards of the relevant countries and regions, and corresponding operation portals are provided for users to choose to authorize or refuse.

[0137] In other words, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in the technical solution of this application all comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0138] According to embodiments of this application, this application also provides an electronic device and a readable storage medium.

[0139] Figure 6 This is a schematic diagram of an electronic device provided in an embodiment of this application. The electronic device includes a receiver 60, a transmitter 61, at least one processor 62, and a memory 63. The electronic device composed of the above components can be used to implement the above-described specific embodiments of this application, which will not be described in detail here.

[0140] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the methods described above.

[0141] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the various steps in the methods described above.

[0142] Various embodiments of the systems and technologies described above in this application can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include: implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0143] The program code used to implement the methods of this application may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or electronic device.

[0144] In the context of this application, a computer-readable storage medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium can be a machine-readable signal medium or a machine-readable storage medium. A computer-readable storage medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of computer-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0145] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0146] The systems and technologies described herein can be implemented in computing systems that include back-end components (e.g., as data electronic devices), or computing systems that include middleware components (e.g., application electronic devices), or computing systems that include front-end components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and technologies described herein), or any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0147] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

[0148] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the principles of this application should be included within the scope of protection of this application.

Claims

1. A power battery equalization control method, characterized in that, A control system applied to the active balancing system of electric vehicles includes: During the charging or discharging process of the power battery in the electric vehicle, the voltage extreme value and reference value of the voltage data of the multiple battery cells contained in the power battery at a target time are obtained; wherein, during the charging process of the power battery in the electric vehicle, the voltage extreme value is the maximum voltage value and the reference value is the average voltage value; during the discharging process of the power battery in the electric vehicle, the voltage extreme value is the minimum voltage value and the reference value is the discharge termination threshold. When the difference between the maximum voltage and the average voltage is greater than or equal to a preset voltage difference threshold, or when the minimum voltage is less than or equal to the discharge termination threshold, the battery cell with the extreme voltage value is taken as the first battery cell, a switch closing command is generated, and the switch closing command is sent to the control terminal of the first equalization switch so that the energy of the first battery cell or the energy of the second battery cell is transferred between the first battery cell and the second battery cell. After sending the switch closing command, it is determined whether the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold, and a first determination result is obtained. When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold, it is determined whether the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than the preset voltage difference threshold, and a second judgment result is obtained; wherein, the third battery cell during the charging process refers to the battery cell with a larger voltage value among the battery cells adjacent to the first battery cell. When the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold, a switch disconnection command is sent to the control terminal of the first equalization switch so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell. The first battery cell is connected in series with the second battery cell via a first branch. During charging, the second battery cell refers to the battery cell with the lower voltage value among the battery cells adjacent to the first battery cell, and during discharging, the second battery cell refers to the battery cell with the higher voltage value among the battery cells adjacent to the first battery cell. The first equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the second battery cell, and the second branch is another branch different from the first branch.

2. The method according to claim 1, characterized in that, After determining whether the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold, and obtaining a second determination result, the method further includes: When the second judgment result indicates that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is not less than a preset voltage difference threshold, a switch closing command is sent to the control terminal of the second equalization switch; wherein, the second equalization switch is the equalization switch in the active equalization module located on the second branch between the first battery cell and the third battery cell; When the first judgment result is that the difference between the voltage value of the first battery cell and the average voltage is less than a preset voltage difference threshold, and the second judgment result is that the difference between the voltage value of the first battery cell and the voltage value of the third battery cell is less than a preset voltage difference threshold, corresponding switch disconnection commands are sent to the control terminals of the first equalization switch and the second equalization switch, respectively, so that the energy of the first battery cell is not transferred between the first battery cell and the second battery cell and between the first battery cell and the third battery cell.

3. The method according to claim 1, characterized in that, The active balancing module further includes a filtering circuit, or includes a filtering circuit and a stabilizing circuit connected to each other, so that the energy of the first battery cell or the second battery cell is transferred between the first battery cell and the second battery cell through the filtering effect of the filtering circuit, or through the filtering effect of the filtering circuit and the stabilizing effect of the stabilizing circuit.

4. An active balancing system, characterized in that, The system includes an interconnected control system, a computing system, and a battery system; wherein the battery system includes a power battery and multiple active balancing modules, wherein the power battery includes multiple battery cells, and an active balancing module is provided on a second branch between two adjacent battery cells, the active balancing module including a balancing switch; the control system is used to execute the method as described in any one of claims 1-3.

5. An electric vehicle, characterized in that, It includes a vehicle control system and an active balancing system, wherein the control system in the active balancing system is used to perform the method as described in any one of claims 1-3.

6. An electronic device, characterized in that, include: At least one processor and memory; The memory stores computer-executed instructions; The at least one processor executes computer execution instructions stored in the memory, causing the at least one processor to perform the method as described in any one of claims 1 to 3.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1 to 3.

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