A battery cell equalization method, device, vehicle controller, and medium

Abstract

The application provides a battery cell equalization method and device for a power battery, a vehicle controller and a medium. The method comprises the following steps: obtaining the equalization channel priority of each single cell; determining whether the actual PCB temperature is less than or equal to a first temperature preset value; if yes, turning on the equalization channels of all the single cells to be equalized; calculating the predicted PCB temperature according to the actual PCB temperature and the single cells to be equalized with the equalization channels turned on; determining the single cells to be turned off and turning off the equalization channels of the single cells to be turned off according to the predicted PCB temperature, the first temperature preset value, the actual PCB temperature, a second temperature preset value and the equalization channel priority of the single cells to be equalized with the equalization channels turned on. The application can prolong the equalization time and improve the equalization efficiency without increasing any hardware cost, so that the consistency of the power battery is improved more quickly, and the use efficiency and service life of the power battery are improved.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a cell balancing determination method, device, vehicle controller, and readable storage medium for power batteries. Background Technology

[0002] To address global energy shortages and environmental problems caused by the heavy use of fossil fuels, new energy vehicles and power battery technology have seen rapid development in recent years. Lithium batteries, as energy storage devices, are widely used in new energy vehicles. The power batteries in new energy vehicles consist of multiple individual lithium batteries connected in series and parallel to form battery packs to meet high voltage requirements. Due to differences in the internal characteristics of the batteries themselves or in the actual working environment, the performance of each individual battery (usually called a single cell, or simply a cell) varies, including its Open Circuit Voltage (OCV), State of Charge (SOC), and internal resistance. This is known as battery pack inconsistency.

[0003] The typical inconsistencies between individual cells are mainly influenced by manufacturing factors and the usage environment. Differences in production processes and material inhomogeneity result in variations in the activation level, thickness, and separators of the positive and negative electrode materials, which cannot be eliminated by improving the manufacturing process. As the number of charge-discharge cycles and usage time of each cell increases, differences in electrolyte density, battery temperature, and self-discharge rate will exacerbate the inconsistencies between cells.

[0004] Inconsistencies among individual cells can affect the charging and discharging efficiency of the power battery and its overall lifespan. Therefore, the BMS (Battery Management System) needs to have the ability to "balance management". It can judge the consistency of cells by monitoring the status of each cell in real time, and adjust inconsistent cells in a timely manner to reduce the differences between cells and improve the performance of the power battery.

[0005] While there are many battery balancing management methods, they can be broadly categorized into two types based on their energy management approach: dissipative balancing and non-dissipative balancing. Non-dissipative balancing involves a Battery Management System (BMS) monitoring individual cells or battery packs. When a cell or pack is fully charged, the corresponding management circuitry transfers energy from the fully charged cell or pack to the cell with the lowest charge. This method is often referred to as "active balancing." Although this method effectively transfers energy from cells—theoretically only electrical energy with very low heat generation—the control circuitry is extremely complex, requiring a high level of intelligence from the BMS, leading to a significant increase in production costs. Therefore, it is not widely used. The other type is dissipative balancing, often called "passive balancing." This method uses a BMS to monitor the status of each cell in real time. When a cell's open voltage (OCV) or state of charge (SOC) is high, the balancing circuit dissipates electrical energy as heat through resistors. Typically, the balancing current for passive balancing is around 50-150mV, resulting in relatively low balancing efficiency. However, its simple circuit structure and lower cost have led to its more widespread application.

[0006] For example, a passive equalization circuit typically includes an equalization switch and an equalization resistor, and the equalization circuit is generally integrated into the BMS controller. When an individual cell reduces its power by dissipating heat through the equalization resistor, the temperature of the BMS controller's PCB (Printed Circuit Board) gradually rises. When the PCB temperature exceeds a first set value, the BMS controller shuts down all equalization circuits; when it falls below a second set value, all equalization circuits are activated. For an example, please refer to [link to example]. Figure 1 , Figure 1 The relationship between the opening / closing of the equalization channel and the PCB temperature during the equalization process is presented in the dissipative equalization provided by relevant technologies. Figure 1 The example shown uses a first setting of 110℃ and a second setting of 100℃. Figure 1 It can be seen that when the PCB temperature exceeds the first set value of 110℃, the BMS controller will shut down all equalization circuits. Once the temperature drops below the second set value of 100℃, the equalization channels will reopen. When the PCB temperature exceeds the first set value of 110℃ again, all equalization channels will shut down again, and once the temperature drops below the second set value of 100℃ again, the equalization channels will reopen, repeating this process until equalization is complete. Figure 1 For example, during long-term equilibrium periods, the time the equilibrium channel is closed accounts for more than 20% of the time the equilibrium channel is open, which significantly affects the equilibrium efficiency.

[0007] It should be noted that the information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a cell balancing method, device, vehicle controller, and readable storage medium for power batteries. This invention can continuously balance some cells while ensuring controllable PCB temperature without increasing any hardware costs, extending the balancing on-time, and improving balancing efficiency. This results in a faster improvement in the consistency of the power battery, thereby improving the battery's efficiency and lifespan.

[0009] To achieve the above objectives, the present invention provides a cell balancing method for power batteries, comprising iteratively executing the following steps during the cell balancing process:

[0010] Obtain the equalization channel priority of each individual cell of the power battery;

[0011] Determine whether the actual PCB temperature of the power battery is less than or equal to the first preset temperature value. If so, activate the equalization channel of all cells to be equalized.

[0012] Calculate the predicted PCB temperature based on the actual PCB temperature and the individual unit to be balanced that currently has the equalization channel activated.

[0013] Based on the predicted PCB temperature, the first preset temperature value, the actual PCB temperature, the second preset temperature value, and the equalization channel priority of the unit to be equalized that currently has its equalization channel enabled, a unit to be shut down is determined; and when a unit to be shut down exists, its equalization channel is shut down; the second preset temperature value is less than the first preset temperature value.

[0014] Optionally, before obtaining the equalization channel priority of each individual cell of the power battery, the method further includes:

[0015] Perform a cell consistency calculation on the power battery to obtain the SOC value of each cell;

[0016] The step of obtaining the equalization channel priority for each of the individual units includes:

[0017] For each of the aforementioned cells, the priority of the equalization channel for that cell is determined based on its SOC value; wherein, the higher the SOC value of the cell, the higher its equalization channel priority.

[0018] Optionally, before determining whether the actual PCB temperature of the power battery is less than or equal to a first preset temperature value, the method further includes determining the cell to be equalized by the following method:

[0019] The minimum SOC value is determined based on the SOC values ​​of all the individual cells of the power battery.

[0020] For each of the monomers, calculate the difference between its SOC value and the minimum SOC value, and determine whether the difference result is greater than a preset SOC value. If so, the monomer is the monomer to be equalized.

[0021] Optionally, calculating the predicted PCB temperature based on the actual PCB temperature and the currently activated equalization channel of the individual unit to be equalized includes:

[0022] For each unit to be balanced that currently has its balancing channel activated, the heat dissipation of the unit to be balanced is calculated based on its balancing current, balancing resistance, and balancing duration.

[0023] The total heat dissipation is obtained based on the heat dissipation of all the units to be balanced that are currently in the balancing channel.

[0024] The predicted temperature of the PCB is calculated based on the actual temperature of the PCB, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB.

[0025] Optionally, before calculating the predicted PCB temperature based on the actual PCB temperature, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB, the method further includes:

[0026] The heat loss is calculated based on the convective heat transfer coefficient, the surface area of ​​the PCB, the actual temperature of the PCB, and the ambient temperature.

[0027] The heat of temperature rise is calculated based on the total heat dissipation and the heat loss.

[0028] The step of calculating the predicted PCB temperature based on the actual PCB temperature, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB includes:

[0029] The predicted temperature of the PCB is calculated based on the actual temperature of the PCB, the heat of temperature rise, the specific heat capacity of the PCB, and the mass of the PCB.

[0030] Optionally, determining the cell to be shut down based on the predicted PCB temperature, the first preset temperature value, the actual PCB temperature, the second preset temperature value, and the equalization channel priority of the cell to be equalized currently having its equalization channel enabled includes:

[0031] Determine whether the predicted PCB temperature is greater than the first preset temperature value:

[0032] If yes, then determine whether the actual temperature of the PCB is greater than the second preset temperature value; if no, then there is no unit to be shut down, and return to the step of obtaining the predicted temperature of the PCB based on the actual temperature of the PCB and the unit to be balanced with the currently activated equalization channel; if yes, then based on the equalization channel priority of the unit to be balanced with the currently activated equalization channel, the unit to be balanced with the lower equalization channel priority is taken as the unit to be shut down.

[0033] Optionally, if the predicted PCB temperature is determined to be less than or equal to the first preset temperature value, the method further includes:

[0034] Monitor the real-time temperature of the PCB and update the actual temperature of the PCB using the monitored real-time temperature.

[0035] Optionally, the step of selecting the unit to be balanced with a lower equalization channel priority as the unit to be closed based on the equalization channel priority of the unit currently having an equalization channel enabled includes:

[0036] The rules for combining the number of equalization channels are determined based on the equalization channel priority of the individual unit to be equalized that currently has an equalization channel activated.

[0037] According to the equalization channel number combination rule, the individual units to be equalized of the currently activated equalization channel are combined to obtain at least two unit combinations;

[0038] For each of the aforementioned unit combinations, the estimated predicted temperature corresponding to the unit combination is calculated based on the actual temperature of the PCB and the unit to be balanced corresponding to the unit combination; and it is determined whether the estimated predicted temperature corresponding to the unit combination is less than the first preset temperature value. If so, the unit combination is a candidate unit combination to be shut down.

[0039] Based on all the candidate combinations of units to be shut down and the preset balancing strategy, a target combination of units to be shut down is determined, and the units to be balanced in the target combination of units to be shut down are taken as the units to be shut down.

[0040] To achieve the above objectives, the present invention also provides a cell balancing device for a power battery, the cell balancing device comprising:

[0041] The single-cell consistency acquisition module is configured to acquire the equalization channel priority of each single cell of the power battery.

[0042] The equalization execution module is configured to determine whether the actual PCB temperature of the power battery is less than or equal to a first preset temperature value. If so, the equalization channel of all cells to be equalized is activated.

[0043] The PCB temperature prediction module is configured to calculate the predicted PCB temperature based on the actual PCB temperature and the single unit to be equalized that currently has its equalization channel activated.

[0044] The equalization channel control module is configured to determine the unit to be shut down based on the predicted PCB temperature, the first preset temperature value, the actual PCB temperature, the second preset temperature value, and the equalization channel priority of the unit to be equalized that currently has an equalization channel open; and to shut down the equalization channel of the unit to be shut down when there is a unit to be shut down; wherein the second preset temperature value is less than the first preset temperature value.

[0045] To achieve the above objectives, the present invention also provides a vehicle controller, which includes the above-described cell balancing device or includes a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, it implements the cell balancing method as described in any of the above claims.

[0046] To achieve the above objectives, the present invention also provides a readable storage medium, characterized in that the readable storage medium stores a computer program, which, when executed by a processor, implements the cell balancing method described in any of the above claims.

[0047] Compared with the prior art, the battery cell equalization method, apparatus, vehicle controller, and readable storage medium provided by the present invention have the following advantages:

[0048] The cell balancing method for power batteries provided by this invention first establishes a solid foundation for determining the cells to be balanced by acquiring the balancing channel priority of each cell. Then, it determines that the actual PCB temperature of the power battery is lower than a first preset temperature value (i.e., the PCB protection temperature, exemplarily as shown in the attached figure). Figure 4 The T shown thermalWhen balancing, the balancing channels of all cells to be balanced are activated, ensuring that all balancing channels are functioning correctly. This not only effectively protects the PCB but also maximizes balancing efficiency. Furthermore, the predicted PCB temperature is obtained based on the actual PCB temperature (which is the initial actual temperature before iteration) and the number of cells with currently activated balancing channels. This provides a reliable basis for subsequent determination of whether to close some balancing channels (based on the predicted PCB temperature, a first preset temperature value, the actual PCB temperature, and a second preset temperature value). Therefore, the cell balancing method provided by this invention, during the cell balancing process, continuously iterates and predicts the PCB temperature change. When the PCB temperature approaches the PCB protection temperature, it switches the number of balancing channels. This allows for continuous balancing of some cells without increasing hardware costs, while maintaining controllable PCB temperature. This extends the balancing duration, improves balancing efficiency, and thus accelerates the improvement of battery consistency, thereby enhancing battery efficiency and lifespan.

[0049] Since the cell balancing device, vehicle controller, and readable storage medium provided by this invention belong to the same inventive concept as the cell balancing method provided by this invention, the cell balancing device, vehicle controller, and readable storage medium provided by this invention have at least all the advantages of the cell balancing method provided by this invention. For details on the beneficial effects of the cell balancing device, vehicle controller, and readable storage medium provided by this invention, please refer to the above description of the beneficial effects of the cell balancing method provided by this invention, which will not be repeated here. Attached Figure Description

[0050] Figure 1 The relationship between the opening / closing of the equalization channel and the PCB temperature during the equalization process is presented in the dissipative equalization provided by related technologies.

[0051] Figure 2 This is a schematic diagram of the overall process of a cell balancing method provided in one embodiment of the present invention;

[0052] Figure 3 This is a schematic diagram showing the correspondence between the voltage of a single cell and the priority of its equalization channel in a specific example of the cell equalization method provided by the present invention.

[0053] Figure 4 This is a schematic diagram of the PCB predicted temperature under different numbers of equalization channels in a specific example of the cell equalization method provided by the present invention.

[0054] Figure 5 This is a schematic diagram illustrating the iterative calculation process of PCB predicted temperature based on the actual PCB temperature.

[0055] Figure 6 This is a schematic diagram illustrating the process of equalization channel control using the cell equalization method provided by the present invention.

[0056] Figure 7 A flowchart illustrating a specific example of the cell balancing method provided by the present invention;

[0057] Figure 8 A schematic diagram showing the comparison between the actual temperature history of the PCB obtained by using the cell balancing method provided in this invention for balancing channel control and the balancing methods of related technologies.

[0058] Figure 9 A structural block diagram of a cell balancing device for a power battery provided in another embodiment of the present invention;

[0059] Figure 10 This is a structural block diagram of a vehicle controller according to another embodiment of the present invention;

[0060] The reference numerals in the attached figures are as follows:

[0061] Unit consistency acquisition module-110, equalization execution module-120, PCB temperature prediction module-130, and equalization channel control module-140;

[0062] Processor-210, memory-220, communication interface-230, communication bus-240. Detailed Implementation

[0063] The following detailed description, in conjunction with the accompanying drawings, provides a method, apparatus, vehicle controller, and readable storage medium for cell balancing in power batteries, based on the present invention. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clarify the illustration of the embodiments of the invention. Please refer to the drawings to make the objectives, features, and advantages of the invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to enable those skilled in the art to understand and read the invention, and are not intended to limit the implementation conditions of the invention. Any modifications to the structure, changes in proportions, or adjustments to the size, provided they produce the same or similar effects and achieve the same objectives as the invention, should still fall within the scope of the technical content disclosed in the invention. Specific design features of the invention disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific application and usage environment. Furthermore, in the embodiments described below, the same reference numerals are sometimes used across different drawings to denote the same parts or parts having the same function, omitting repeated descriptions. In this specification, similar reference numerals and letters are used to denote similar items; therefore, once an item is defined in one figure, it need not be discussed further in subsequent figures. Furthermore, if the methods described herein involve a series of steps, and the order of these steps presented herein is not necessarily the only possible order in which they can be performed, some of the described steps may be omitted and / or other steps not described herein may be added to the method.

[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The singular forms “a,” “an,” and “the” include plural objects. The term “or” is generally used to mean “and / or,” the term “several” is generally used to mean “at least one,” and the term “at least two” is generally used to mean “two or more.” Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0065] The core idea of ​​this invention is to provide a cell balancing method, device, vehicle controller, and readable storage medium for power batteries. This invention can continuously balance some cells while ensuring that the PCB temperature is controllable, without increasing any hardware costs, thereby extending the balancing on-time and improving balancing efficiency. This results in a faster improvement in the consistency of the power battery, and thus improves the efficiency and lifespan of the power battery.

[0066] It should be noted that the cell balancing method, apparatus, and readable storage medium for power batteries provided by this invention can be applied to the vehicle controller provided by this invention, and can be applied to electric vehicles. It should be understood that the terms "automobile," "vehicle," or "of an automobile," or other similar terms as used herein, include general motor vehicles, such as passenger vehicles including SUVs, buses, trucks, and various commercial vehicles, and include hybrid vehicles, electric vehicles, and plug-in hybrid electric vehicles. Furthermore, it should be noted that, as those skilled in the art will understand, this invention does not limit the positive and negative electrode materials, electrolyte materials, module structure, or product appearance of the power battery cells. For example, regarding the positive electrode material of the cells, the power battery can be, but is not limited to, lithium iron phosphate batteries, lithium cobalt oxide batteries, lithium manganese oxide batteries, binary lithium batteries, and ternary lithium batteries, etc. In addition, the cell balancing method for power batteries provided by this invention does not impose excessive limitations on the application scenarios of the power battery.

[0067] To achieve the above-mentioned goals, a first embodiment of the present invention provides a cell balancing method for power batteries. Specifically, please refer to... Figure 2 , Figure 2 This is a schematic diagram of the overall process of the cell balancing method provided in this embodiment. From Figure 2 As can be seen, the cell balancing method provided in this embodiment includes iteratively executing the following steps during the cell balancing process:

[0068] S100: Obtain the equalization channel priority of each cell of the power battery;

[0069] S200: Determine whether the actual temperature of the PCB of the power battery is less than or equal to the first preset temperature value. If so, open the equalization channel of all cells to be equalized.

[0070] S300: Calculate the predicted PCB temperature based on the actual PCB temperature and the single unit to be balanced that currently has the balancing channel activated;

[0071] S400: Based on the predicted PCB temperature, the first preset temperature value, the actual PCB temperature, the second preset temperature value, and the equalization channel priority of the unit to be equalized that currently has an open equalization channel, determine the unit to be shut down; and shut down the equalization channel of the unit to be shut down when there is a unit to be shut down; the second preset temperature value is less than the first preset temperature value.

[0072] The cell balancing method for power batteries provided by this invention first establishes a solid foundation for determining the cells to be balanced by acquiring the balancing channel priority of each cell. Then, it determines that the actual PCB temperature of the power battery is lower than a first preset temperature value (i.e., the PCB protection temperature, exemplarily as shown in the attached figure). Figure 4 The T shown thermal When balancing, the balancing channels of all cells to be balanced are activated, ensuring that all balancing channels are functioning correctly. This not only effectively protects the PCB but also maximizes balancing efficiency. Furthermore, the predicted PCB temperature is obtained based on the actual PCB temperature (which is the initial actual temperature before iteration) and the number of cells with currently activated balancing channels. This provides a reliable basis for subsequent determination of whether to close some balancing channels (based on the predicted PCB temperature, a first preset temperature value, the actual PCB temperature, and a second preset temperature value). Therefore, the cell balancing method provided by this invention, during the cell balancing process, continuously iterates and predicts the PCB temperature change. When the PCB temperature approaches the PCB protection temperature, it switches the number of balancing channels. This allows for continuous balancing of some cells without increasing hardware costs, while maintaining controllable PCB temperature. This extends the balancing duration, improves balancing efficiency, and thus accelerates the improvement of battery consistency, thereby enhancing battery efficiency and lifespan.

[0073] It should be noted that, as those skilled in the art will understand, the present invention does not impose any limitation on the specific value of the first temperature preset value. Preferably, the first temperature preset value can be the PCB protection temperature or slightly less than the PCB protection temperature; for example, the first temperature preset value can be 110°C. Similarly, the present invention does not impose any limitation on the second temperature preset value; it can be understood that the second temperature preset value is less than and preferably close to the first temperature preset value. For example, the second temperature preset value can be set by the following formula (1):

[0074] Second preset temperature value = First preset temperature value - △(1)

[0075] For example, the value of Δ is 10℃, that is, when the first preset temperature is 110℃, the second preset temperature is 100℃. It should be understood that the value of Δ is 10℃, which is merely an illustrative description and not a limitation of the present invention. The present invention does not impose excessive limitations on this, and the specific value of Δ can be reasonably set according to actual needs. Furthermore, the present invention does not limit the method of obtaining the actual temperature of the PCB; for example, it can be obtained through measurement by a temperature sensor.

[0076] Please continue reading Figure 2In some exemplary embodiments, before obtaining the equalization channel priority of each cell of the power battery in step S100, the method further includes:

[0077] S001: Perform a single-cell consistency calculation on the power battery to obtain the SOC value of each single cell;

[0078] Correspondingly, step S100, which involves obtaining the equalization channel priority for each of the individual units, includes:

[0079] For each of the aforementioned cells, the priority of the equalization channel for that cell is determined based on its SOC value; wherein, the higher the SOC value of the cell, the higher its equalization channel priority.

[0080] Therefore, the cell balancing method for power batteries provided by this invention calculates the SOC value of each cell by performing a cell consistency calculation, thereby providing a reliable basis for obtaining the balancing channel priority of each cell. Furthermore, the balancing channel priority of each cell is determined based on the SOC value, with a higher SOC value corresponding to a higher balancing priority. This lays a solid foundation for further improving balancing efficiency and rapidly enhancing the consistency of the power battery.

[0081] Specifically, after the power battery is subjected to high voltage, the polarization effect of the power battery gradually disappears. After the entire pack is left to stand for a certain period of time, the voltage of each individual cell tends to stabilize. At this time, the magnitude of the OCV voltage can reflect the state of charge (SOC) of the individual cell. Based on this, in some exemplary embodiments, the SOC value of each individual cell can be obtained based on its OCV voltage. However, it is obvious that this is not a limitation of the present invention, and in other embodiments, methods other than OCV voltage can be used to obtain the SOC value of each individual cell. For more detailed information on how to obtain the SOC value of each individual cell of the power battery, please refer to the relevant technical adaptations known to those skilled in the art, which will not be elaborated here.

[0082] In addition to judging the overall consistency of the package, based on the correspondence between OCV voltage and SOC value, it can also perform equal discharge on cells with high SOC charge according to the OCV voltage level, so that their charge is consistent with that of the smallest cell, thereby improving the overall consistency of the package.

[0083] For example, please see Figure 3 , Figure 3 This diagram illustrates the correspondence between the voltage of a single cell and the priority of its equalization channel in a specific example of the cell equalization method provided by this invention. Figure 3It can be seen that the voltage of cell number

[34] is the lowest, with an OCV of 2702mV. The voltage and charge of the other cells are much higher than that of cell

[34] . The cells with the highest priority in the balancing channel are those with an OCV voltage around 3200mV, numbered [1], [3], ...,

[99] . The cells with the next highest priority in the balancing channel have an OCV voltage around 2900mV, numbered [8],

[12] , ...,

[100] . The priority of balancing each cell is determined by sorting the cells from highest to lowest OCV voltage after resting.

[0084] It should be specifically noted that, as those skilled in the art will understand, this invention does not specifically limit the number of priorities or the rules for dividing the equalization channel priorities. For example, in some embodiments, the equalization channel priority of each unit corresponds one-to-one with its OCV voltage; if the OCV voltages of different units are different, their corresponding equalization channel priorities will also be different. In other embodiments, the units can also be divided into several ranges based on the magnitude of the OCV voltage, and units within the same OCV voltage range have the same equalization channel priority.

[0085] Preferably, in some exemplary embodiments, before determining in step S200 whether the actual PCB temperature of the power battery is less than or equal to a first preset temperature value, the method further includes determining the cell to be equalized by:

[0086] The minimum SOC value is determined based on the SOC values ​​of all the individual cells of the power battery.

[0087] For each of the monomers, calculate the difference between its SOC value and the minimum SOC value, and determine whether the difference result is greater than a preset SOC value. If so, the monomer is the monomer to be equalized.

[0088] Therefore, the cell balancing method for power batteries provided by this invention determines the cells to be balanced based on the SOC value of each cell and a preset SOC value (the allowable SOC deviation for power battery consistency, i.e., the maximum deviation between the cells with the smallest SOC value and the cells with the smallest SOC value, excluding the cell with the smallest SOC value). The logic is simple and easy to implement. It is understood that this invention does not impose excessive restrictions on the specific value of the preset SOC value, and it should be reasonably set according to actual needs. Furthermore, it is understood that if there are no cells to be balanced (i.e., the consistency of the power battery is good), then subsequent steps S200, S300, and S400 do not need to be run.

[0089] Furthermore, from Figure 2As can be seen, in step S200, if it is determined that the actual temperature of the power battery's PCB is greater than the first preset temperature value, then it is not necessary to open the equalization channel of the cell to be equalized, and it is not necessary to execute subsequent steps S300 and S400. Therefore, it is possible to avoid the PCB temperature rise caused by opening the equalization channel, thereby better protecting the PCB.

[0090] In some exemplary embodiments, step S300 calculates the predicted PCB temperature based on the actual PCB temperature and the individual unit to be equalized currently having its equalization channel activated, including:

[0091] S310: For each unit to be balanced that currently has an open balancing channel, calculate the heat dissipation of the unit based on its balancing current, balancing resistance, and balancing duration.

[0092] S320: Calculate the total heat dissipation based on the heat dissipation of all the units to be balanced that are currently in the balancing channel;

[0093] S330: The predicted temperature of the PCB is calculated based on the actual temperature of the PCB, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB.

[0094] Therefore, the cell balancing method for power batteries provided by this invention makes full use of the relatively simple working scenario of the BMS controller. Based on Joule's law, it calculates the heat release of the cell to be balanced that is currently balancing the channel. Then, it can estimate the PCB temperature based on the heat release of the cell to be balanced that is currently balancing the channel. By predicting the PCB temperature, it can be determined whether the PCB will overheat, thus laying a solid foundation for switching the balancing channel during the balancing process to improve balancing efficiency.

[0095] For example, please see Figure 4 , Figure 4 This is a schematic diagram illustrating the predicted PCB temperature under different numbers of equalization channels, representing a specific example of the cell equalization method provided by this invention. Figure 4 It can be seen that the predicted temperature is related to the number of equalization channels that are turned on. The more equalization channels that are turned on, the higher the predicted PCB temperature will be.

[0096] Furthermore, as one preferred embodiment, in step S310, for each unit to be balanced that currently has its balancing channel activated, the heat dissipation of that unit can be calculated using the following formula (2):

[0097]

[0098] In equation (2), Q cellHeat dissipation per unit (J, Joules), I b R is the equalization current (A, Amperes) of the cell to be equalized. d The equalization resistance is Ω (ohms), and t is the equalization duration (s).

[0099] Furthermore, the equalization current I in equation (2) b This can be obtained based on the voltage and equalization resistance of the cell to be equalized. For example, the equalization current I... b It can be calculated using the following formula (3):

[0100]

[0101] In equation (3), I b To balance the current, U cell R is the voltage of the cell to be balanced. d This is the equalization resistor for the equalization channel corresponding to the cell to be equalized.

[0102] Furthermore, the balancing time t in equation (2) can be calculated based on the charge difference between the cell to be balanced and the cell with the smallest SOC value (i.e., the SOC balancing amount), the battery capacity of the cell to be balanced, and the balancing current. For example, the balancing time t can be calculated using the following equation (4):

[0103]

[0104] In equation (4), t is the equilibrium time, ΔSOC is the charge difference, and C cell For the battery capacity of the cell to be balanced, I b To balance the current.

[0105] For example, step S320 calculates the total heat dissipation based on the heat dissipation of all the units to be balanced that currently have the balancing channel activated, including by using the following formula (5):

[0106]

[0107] In equation (5), Q balance Q represents the total heat dissipation. i The heat dissipation of the i-th unit to be balanced is specifically calculated using the above formula (2); N is the number of units to be balanced that currently have the balancing channel enabled on the PCB.

[0108] Preferably, in some exemplary embodiments, before step S330 calculates the predicted PCB temperature based on the actual PCB temperature, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB, the method further includes:

[0109] SA1: The heat loss is calculated based on the convective heat transfer coefficient, the surface area of ​​the PCB, the actual temperature of the PCB, and the ambient temperature.

[0110] SA2: Calculate the heat of temperature rise based on the total heat dissipation and the heat loss;

[0111] Correspondingly, step S330 calculates the predicted PCB temperature based on the actual PCB temperature, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB, including:

[0112] S331: The predicted temperature of the PCB is calculated based on the actual temperature of the PCB, the heat of temperature rise, the specific heat capacity of the PCB, and the mass of the PCB.

[0113] Therefore, based on the actual working condition that the PCB is in contact with the air and some heat is dissipated into the air when the PCB temperature rises, thus reducing the PCB's temperature rise effect, the cell balancing method for power batteries provided by this invention fully considers the heat loss, calculates the temperature rise heat based on the total heat dissipation and the heat loss, improves the calculation accuracy of the temperature rise heat, and further improves the cell balancing efficiency.

[0114] For example, step SA1 calculates the heat loss based on the convective heat transfer coefficient, the surface area of ​​the PCB, the actual temperature of the PCB, and the ambient temperature, including by using the following formula (6):

[0115]

[0116] In equation (6), α is the convective heat transfer coefficient (unit: W / (m³)). 2 ·℃), F is the surface area of ​​the power battery PCB (unit: m²). 2 ), T act T represents the measured temperature of the PCB. air The ambient temperature.

[0117] Exemplary, in some exemplary embodiments, step S331 includes calculating the predicted PCB temperature based on the actual PCB temperature, the heat of temperature rise, the specific heat capacity of the PCB, and the mass of the PCB, including using the following formula (7):

[0118]

[0119] In equation (7), T pre The predicted PCB temperature is T0, where T0 is the actual PCB temperature obtained at the start of equalization, and C is the temperature at which the PCB temperature is measured. pcb This is the specific heat capacity of the PCB (unit: J / (kg·K)), m pcbQ is the mass of the PCB (unit: kilograms). balance -Q air The heat of temperature increase, where Q balance Q represents the total heat dissipation. air To dissipate heat.

[0120] In some exemplary embodiments, step S400 determines the cell to be shut down based on the predicted PCB temperature, the first preset temperature value, the actual PCB temperature, the second preset temperature value, and the equalization channel priority of the cell to be equalized that currently has an equalization channel enabled, including:

[0121] Determine whether the predicted PCB temperature is greater than the first preset temperature value:

[0122] If yes, then determine whether the actual temperature of the PCB is greater than the second preset temperature value; if no, then there is no unit to be shut down, and return to the step of obtaining the predicted temperature of the PCB based on the actual temperature of the PCB and the unit to be balanced with the currently activated equalization channel; if yes, then based on the equalization channel priority of the unit to be balanced with the currently activated equalization channel, the unit to be balanced with the lower equalization channel priority is taken as the unit to be shut down.

[0123] Therefore, the cell balancing method for power batteries provided by this invention, when the actual PCB temperature is less than or equal to a second preset temperature value (as described above, the second preset temperature value is less than the first preset temperature value, i.e., the PCB protection temperature), even if the predicted PCB temperature is greater than the first preset temperature value (usually the PCB protection temperature), does not close the balancing channels but continues to maintain the currently open number of balancing channels, and continues to iteratively execute the steps related to the predicted temperature. This improves balancing efficiency while ensuring PCB safety. If the predicted PCB temperature is greater than the first preset temperature value and the actual PCB temperature is greater than the second preset temperature value, it indicates that if the currently open number of balancing channels continues to be maintained, the PCB temperature may exceed the PCB protection temperature. By closing the cells with lower balancing channel priority, the heat dissipation during the balancing process can be effectively reduced, thereby effectively reducing the PCB temperature rise. Simultaneously, keeping the balancing channels of cells with higher balancing channel priority open extends the balancing time, improves balancing efficiency, and thus allows for faster improvement in the consistency of the power battery, thereby improving the battery's efficiency and lifespan.

[0124] In some exemplary embodiments, when the predicted PCB temperature is determined to be less than or equal to the first preset temperature value, the method further includes: monitoring the real-time PCB temperature and updating the actual PCB temperature using the monitored real-time PCB temperature. This can further improve the accuracy of the predicted PCB temperature. Furthermore, in subsequent iterations, the updated predicted PCB temperature is compared with the first preset temperature value, and subsequent equalization control is performed based on the comparison result. Thus, the improved accuracy of the predicted temperature can further improve the equalization efficiency.

[0125] Exemplary, in some exemplary embodiments, step S331 includes calculating the predicted PCB temperature based on the actual PCB temperature, the heat of temperature rise, the specific heat capacity of the PCB, and the mass of the PCB, including using the following formula (8):

[0126]

[0127] In equation (8), T pre-new T is the new predicted PCB temperature calculated based on the actual PCB temperature after iteration. act To obtain the actual PCB temperature in real time during the balancing process, C pcb This is the specific heat capacity of the PCB (unit: J / (kg·K)), m pcb Q is the mass of the PCB (unit: kilograms). balance -Q air The heat of temperature increase, where Q balance Q represents the total heat dissipation. air To dissipate heat.

[0128] For example, please see Figure 5 , Figure 5 This is a schematic diagram illustrating the iterative calculation process of PCB predicted temperature based on the actual PCB temperature. From... Figure 5 Yes, as the iterations continue, the calculated predicted PCB temperature gets closer and closer to the actual PCB temperature, and the prediction accuracy is improved.

[0129] Preferably, in some exemplary embodiments, the step of selecting the cell to be balanced with a lower equalization channel priority as the cell to be balanced based on the equalization channel priority of the cell to be balanced currently having an equalization channel enabled includes:

[0130] The rules for combining the number of equalization channels are determined based on the equalization channel priority of the individual unit to be equalized that currently has an equalization channel activated.

[0131] According to the equalization channel number combination rule, the individual units to be equalized of the currently activated equalization channel are combined to obtain at least two unit combinations;

[0132] For each of the aforementioned unit combinations, the estimated predicted temperature corresponding to the unit combination is calculated based on the actual temperature of the PCB and the unit to be balanced corresponding to the unit combination; and it is determined whether the estimated predicted temperature corresponding to the unit combination is less than the first preset temperature value. If so, the unit combination is a candidate unit combination to be shut down.

[0133] Based on all the candidate combinations of units to be shut down and the preset balancing strategy, a target combination of units to be shut down is determined, and the units to be balanced in the target combination of units to be shut down are taken as the units to be shut down.

[0134] Specifically, this invention does not limit the specific content of the equalization channel number combination rule. Exemplarily, in some exemplary embodiments, the equalization channel number combination rule includes the number of equalization channels in each individual unit combination, where the first individual unit combination includes all units to be equalized, and other individual unit combinations are subsets of the first individual unit combination. The following explanation uses six units to be equalized with equalization channel priorities of 1, 2, 3, 4, 5, and 6 (the larger the value, the lower the equalization channel priority). In one specific example, the above six units to be equalized have three individual unit combinations: a unit combination with six equalization channels including all units to be equalized, a unit combination with four equalization channels including equalization channel priorities of 1, 2, 3, and 4, and a unit combination with two equalization channels including equalization channel priorities of 1 and 2. In another specific example, the above six units to be equalized have two individual unit combinations: a unit combination with six equalization channels including all units to be equalized, and a unit combination with three equalization channels including equalization channel priorities of 1, 2, and 3. It should be understood that, as those skilled in the art will appreciate, the present invention does not impose excessive restrictions on the number of equalization channels in each unit combination, and the difference in the number of equalization channels between unit combinations can be the same or different.

[0135] For more detailed information on the estimated predicted temperatures corresponding to individual unit combinations, please refer to the above section on PCB predicted temperatures for adaptive understanding; this article will not repeat it here.

[0136] Furthermore, the present invention does not impose excessive limitations on the preset equalization strategy. For example, in some preferred embodiments, the estimated predicted temperatures of the candidate combinations of units to be shut down can be sorted from high to low, and the candidate combination of units to be shut down with the highest estimated predicted temperature can be used as the target combination of units to be shut down to maximize equalization efficiency. In other embodiments, the candidate combination of units to be shut down with the second highest estimated predicted temperature can also be used as the target combination of units to be shut down to maximize equalization efficiency while maintaining the PCB temperature at a higher level for a longer period, thereby better protecting the PCB. It is understood that the specific content of the preset equalization strategy can be reasonably set according to actual conditions, and will not be listed one by one here.

[0137] Please continue reading Figure 4 and Figure 6 ,in, Figure 6 This is a schematic diagram illustrating the process of equalization channel control using the cell equalization method provided by this invention. Figure 4 As shown, if the number of individual units to be balanced in the current equalization channel is 14, the calculated maximum predicted PCB temperature is 119.6℃. This temperature exceeds the PCB protection temperature T. thermal (i.e., the first preset temperature is 110℃). If the second preset temperature is 100℃, and the most efficient balancing strategy is adopted, according to... Figure 4 It can be seen that when the number of equalization channels is 12, the predicted highest temperature is 106.5986383℃, which is lower than the first preset temperature value of 110℃. For example... Figure 6 As shown, by optimizing the number of equalization channels, i.e., closing 2 equalization channels and keeping only 12 equalization channels, it is possible to avoid the PCB overheating and shutting down all equalization channels, thereby improving the efficiency of passive equalization.

[0138] For example, please see Figure 7 and Figure 8 ,in, Figure 7 A flowchart illustrating a specific example of the cell balancing method provided by the present invention; Figure 8 This diagram illustrates a comparison between the actual temperature history of a PCB obtained using the cell balancing method provided in this invention for balancing channel control and balancing methods from related technologies. From... Figure 7 As can be seen, this example mainly includes the following steps:

[0139] Step SB1: Calculate the consistency of individual power battery cells;

[0140] Step SB2: Calculate the equalization channel priority of each cell in the power battery;

[0141] Step SB3: Determine if the actual PCB temperature is greater than the PCB protection temperature (i.e., the first preset temperature value): If yes, then disable equalization and end this equalization process; if no, proceed to step SB4.

[0142] Step SB4: Open the equalization channels for all cells to be equalized;

[0143] Step SB5: Obtain the predicted PCB temperature;

[0144] Step SB6: Determine if the predicted PCB temperature is greater than the PCB protection temperature. If yes, proceed to step SB7; otherwise, proceed to step SB8.

[0145] Step SB7: Determine whether the actual PCB temperature is greater than the second preset temperature value (lower than the PCB protection temperature and with a small difference from the PCB protection temperature; for example, if the PCB protection temperature is 110℃ and the second preset temperature value is 100℃). If not, return to step SB5; if yes, close the equalization channel with lower priority and retain the equalization channel of the unit to be equalized with higher priority, and return to execute step SB2.

[0146] Step SB8: Monitor the real-time temperature of the PCB, update the actual temperature of the PCB using the real-time temperature, and return to execute step SB5.

[0147] from Figure 8 As can be seen, when the predicted PCB temperature does not exceed the PCB protection temperature, all equalization channels are normally open. When the predicted PCB temperature exceeds the PCB protection temperature, the low-priority equalization channels are closed to keep the actual PCB temperature below the PCB protection temperature (e.g., 110℃), while the high-priority equalization channels remain open, thereby improving the passive equalization efficiency.

[0148] Based on the same inventive concept, another embodiment of the present invention provides a cell balancing device for power batteries. Specifically, please refer to... Figure 9 ,from Figure 9As can be seen, the cell balancing device provided in this embodiment includes a cell consistency acquisition module 110, a balancing execution module 120, a PCB temperature prediction module 130, and a balancing channel control module 140. Specifically, the cell consistency acquisition module 110 is configured to acquire the balancing channel priority of each cell of the power battery. The balancing execution module 120 is configured to determine whether the actual PCB temperature of the power battery is less than or equal to a first preset temperature value; if so, to open the balancing channels of all cells to be balanced. The PCB temperature prediction module 130 is configured to calculate the predicted PCB temperature based on the actual PCB temperature and the cells to be balanced that currently have their balancing channels open. The balancing channel control module 140 is configured to determine the cells to be shut down based on the predicted PCB temperature, the first preset temperature value, the actual PCB temperature, a second preset temperature value, and the balancing channel priority of the cells to be balanced that currently have their balancing channels open; and to close the balancing channel of the cells to be shut down when such cells exist; wherein the second preset temperature value is less than the first preset temperature value.

[0149] Therefore, the cell balancing device provided by this invention, during the cell balancing process, continuously iterates and predicts the change history of PCB temperature. When the PCB temperature approaches the PCB protection temperature, it can switch the number of balancing channels. Thus, without increasing any hardware costs, it can ensure that some cells are continuously balanced while keeping the PCB temperature controllable, extend the balancing on-time, improve balancing efficiency, and thus improve the consistency of the power battery more quickly, thereby improving the power battery's efficiency and lifespan.

[0150] It should be noted that, as those skilled in the art will understand, since the basic principle of the cell balancing device provided by this invention is the same as that of the cell balancing method provided by this invention, for more detailed information on the parts of the cell balancing device provided by this invention not mentioned in this embodiment, please refer to the relevant description of the cell balancing method described above for an adaptive understanding, and will not be elaborated here.

[0151] Another embodiment of the present invention provides a vehicle controller, the vehicle controller including a cell equalization device as described in the embodiments herein.

[0152] Another embodiment of the present invention provides a different vehicle controller. For example, please refer to... Figure 10 , Figure 10 This is a block diagram of the vehicle controller provided in this embodiment. Figure 10As shown, the vehicle controller provided in this embodiment includes a processor 210 and a memory 220. The memory 220 stores a computer program. When the computer program is executed by the processor 210, it implements the cell balancing method provided in any of the embodiments above. Since the vehicle controller provided in this embodiment and the cell balancing method provided by this invention belong to the same inventive concept, the vehicle controller provided in this embodiment has at least all the advantages of the cell balancing method provided by this invention. For details, please refer to the relevant description of the beneficial effects of the cell balancing method above, which will not be repeated here.

[0153] For example, such as Figure 10 As shown, the vehicle controller may further include a communication interface 230 and a communication bus 240, wherein the processor 210, the communication interface 230, and the memory 220 communicate with each other via the communication bus 240. The communication bus 240 includes, but is not limited to, a CAN bus. For ease of illustration, only one thick line is used in the figure, but this does not imply that there is only one bus or one type of bus. The communication interface 230 is used for communication between the aforementioned vehicle controller (e.g., a BMS controller, i.e., a battery management controller) and other vehicle controllers (e.g., a vehicle controller, a motor controller, etc., not shown in the figure). The communication bus 240 connects the aforementioned vehicle controller (e.g., a BMS controller) and other vehicle controllers (e.g., a motor controller, etc., not shown in the figure) into a closed-loop system, enabling each vehicle controller to perform communication and data transmission in multiple operating states (parking state, charging state, starting state, running state, vehicle forward and reverse state, regenerative braking state, mechanical braking state, general fault state, major fault state), thereby realizing the vehicle control function.

[0154] The processor 210 referred to in this invention can be a microcontroller unit (MCU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor 210 is the control center of the vehicle controller, connecting various parts of the entire vehicle controller via various interfaces and lines.

[0155] The memory 220 can be used to store the computer program. The processor 210 implements various functions of the vehicle controller by running or executing the computer program stored in the memory 220 and calling the data stored in the memory 220.

[0156] The memory 220 may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0157] A fourth embodiment of the present invention provides a readable storage medium storing a computer program. When executed by a processor, the computer program can implement the cell balancing method described above. Since the readable storage medium and the cell balancing method provided by the present invention belong to the same inventive concept, the readable storage medium provided by the present invention possesses at least all the advantages of the cell balancing method provided by the present invention. For details regarding the beneficial effects of the readable storage medium provided by the present invention, please refer to the above description of the beneficial effects of the cell balancing method provided by the present invention; further details will not be repeated here.

[0158] The readable storage medium of embodiments of the present invention can be any combination of one or more computer-readable media. The readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (not exhaustive examples) of a computer-readable storage medium include: an electrical connection having one or more wires, a portable computer hard disk, a hard disk, 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 device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, apparatus, or device.

[0159] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0160] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0161] Compared with the prior art, the present invention provides a cell balancing method, apparatus, vehicle controller, and readable storage medium for power batteries, which have the following advantages:

[0162] The cell balancing method provided by this invention continuously predicts the PCB temperature change process during cell balancing. When the PCB temperature approaches the PCB protection temperature, the number of balancing channels can be switched. Thus, without increasing any hardware costs, some cells can be continuously balanced while ensuring that the PCB temperature is controllable. This extends the balancing time and improves balancing efficiency, thereby improving the consistency of the power battery more quickly and ultimately enhancing the battery's efficiency and lifespan.

[0163] Since the cell balancing device, vehicle controller, and readable storage medium provided by this invention belong to the same inventive concept as the cell balancing method provided by this invention, the cell balancing device, vehicle controller, and readable storage medium provided by this invention have at least all the advantages of the cell balancing method provided by this invention. For details on the beneficial effects of the cell balancing device, vehicle controller, and readable storage medium provided by this invention, please refer to the above description of the beneficial effects of the cell balancing method provided by this invention, which will not be repeated here.

[0164] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0165] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0166] The above description is merely a preferred embodiment of a cell balancing method, apparatus, vehicle controller, and readable storage medium for power batteries provided by the present invention, and is not intended to limit the scope of the invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure are within the protection scope of the present invention. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the present invention and its equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A cell balancing method for power batteries, characterized in that, include: The following steps are iteratively executed during the cell equalization process: Obtain the equalization channel priority of each individual cell of the power battery; Determine whether the actual PCB temperature of the power battery is less than or equal to the first preset temperature value. If so, activate the equalization channel of all cells to be equalized. Calculate the predicted PCB temperature based on the actual PCB temperature and the individual unit to be balanced that currently has the equalization channel activated. Identify the cell to be shut down; and shut down the equalization channel of the cell to be shut down when the cell to be shut down exists; In the following steps for determining the cell to be shut down, the second preset temperature value is less than the first preset temperature value; The steps for identifying the individual cells to be shut down include: Determine whether the predicted PCB temperature is greater than the first preset temperature value: If yes, then determine whether the actual PCB temperature is greater than the second preset temperature value: if no, then there is no unit to be shut down, and return to the step of obtaining the predicted PCB temperature based on the actual PCB temperature and the unit to be balanced currently with the equalization channel enabled; if yes, then determine the unit to be shut down in the following way: The rules for combining the number of equalization channels are determined based on the equalization channel priority of the individual unit to be equalized that currently has an equalization channel activated. According to the equalization channel number combination rule, the individual units to be equalized of the currently activated equalization channel are combined to obtain at least two unit combinations; For each of the aforementioned unit combinations, the estimated predicted temperature corresponding to the unit combination is calculated based on the actual temperature of the PCB and the unit to be balanced corresponding to the unit combination; and it is determined whether the estimated predicted temperature corresponding to the unit combination is less than the first preset temperature value. If so, the unit combination is a candidate unit combination to be shut down. Based on all the candidate combinations of units to be shut down and the preset balancing strategy, a target combination of units to be shut down is determined, and the units to be balanced in the target combination of units to be shut down are taken as the units to be shut down.

2. The cell balancing method according to claim 1, characterized in that, Before obtaining the equalization channel priority of each individual cell of the power battery, the method further includes: Perform a cell consistency calculation on the power battery to obtain the SOC value of each cell; The step of obtaining the equalization channel priority for each of the individual units includes: For each of the aforementioned cells, the priority of the equalization channel for that cell is determined based on its SOC value; wherein, the higher the SOC value of the cell, the higher its equalization channel priority.

3. The cell balancing method according to claim 2, characterized in that, Before determining whether the actual PCB temperature of the power battery is less than or equal to a first preset temperature value, the method further includes determining the cell to be equalized by the following method: The minimum SOC value is determined based on the SOC values ​​of all the individual cells of the power battery. For each of the monomers, calculate the difference between its SOC value and the minimum SOC value, and determine whether the difference result is greater than a preset SOC value. If so, the monomer is the monomer to be equalized.

4. The cell balancing method according to claim 1, characterized in that, The step of calculating the predicted PCB temperature based on the actual PCB temperature and the currently activated equalization channel of the individual unit to be equalized includes: For each unit to be balanced that currently has its balancing channel activated, the heat dissipation of the unit to be balanced is calculated based on its balancing current, balancing resistance, and balancing duration. The total heat dissipation is obtained based on the heat dissipation of all the units to be balanced that are currently in the balancing channel. The predicted temperature of the PCB is calculated based on the actual temperature of the PCB, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB.

5. The cell balancing method according to claim 4, characterized in that, Before calculating the predicted PCB temperature based on the actual PCB temperature, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB, the method further includes: The heat loss is calculated based on the convective heat transfer coefficient, the surface area of ​​the PCB, the actual temperature of the PCB, and the ambient temperature. The heat of temperature rise is calculated based on the total heat dissipation and the heat loss. The step of calculating the predicted PCB temperature based on the actual PCB temperature, the total heat dissipation, the specific heat capacity of the PCB, and the mass of the PCB includes: The predicted temperature of the PCB is calculated based on the actual temperature of the PCB, the heat of temperature rise, the specific heat capacity of the PCB, and the mass of the PCB.

6. The cell balancing method according to claim 1, characterized in that, If the predicted PCB temperature is determined to be less than or equal to the first preset temperature value, the method further includes: Monitor the real-time temperature of the PCB and update the actual temperature of the PCB using the monitored real-time temperature.

7. A cell balancing device for power batteries, characterized in that, The cell equalization device includes: The single-cell consistency acquisition module is configured to acquire the equalization channel priority of each single cell of the power battery. The equalization execution module is configured to determine whether the actual PCB temperature of the power battery is less than or equal to a first preset temperature value. If so, the equalization channel of all cells to be equalized is activated. The PCB temperature prediction module is configured to calculate the predicted PCB temperature based on the actual PCB temperature and the single unit to be equalized that currently has its equalization channel activated. The equalization channel control module is configured to determine a cell to be shut down; and to shut down the equalization channel of the cell to be shut down when the cell to be shut down exists; the second preset temperature value in the following step of determining the cell to be shut down is less than the first preset temperature value; The steps for identifying the individual cells to be shut down include: Determine whether the predicted PCB temperature is greater than the first preset temperature value: If yes, then determine whether the actual PCB temperature is greater than the second preset temperature value: if no, then there is no unit to be shut down, and return to the step of obtaining the predicted PCB temperature based on the actual PCB temperature and the unit to be balanced currently with the equalization channel enabled; if yes, then determine the unit to be shut down in the following way: The rules for combining the number of equalization channels are determined based on the equalization channel priority of the individual unit to be equalized that currently has an equalization channel activated. According to the equalization channel number combination rule, the individual units to be equalized of the currently activated equalization channel are combined to obtain at least two unit combinations; For each of the aforementioned unit combinations, the estimated predicted temperature corresponding to the unit combination is calculated based on the actual temperature of the PCB and the unit to be balanced corresponding to the unit combination; and it is determined whether the estimated predicted temperature corresponding to the unit combination is less than the first preset temperature value. If so, the unit combination is a candidate unit combination to be shut down. Based on all the candidate combinations of units to be shut down and the preset balancing strategy, a target combination of units to be shut down is determined, and the units to be balanced in the target combination of units to be shut down are taken as the units to be shut down.

8. A vehicle controller, characterized in that, The device includes the cell balancing apparatus as described in claim 7, or includes a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, implements the cell balancing method as described in any one of claims 1 to 6.

9. A readable storage medium, characterized in that, The readable storage medium stores a computer program, which, when executed by a processor, implements the cell balancing method according to any one of claims 1 to 6.

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