CN115395118A - Battery pack charge balance control method, device, battery management system and medium - Google Patents

Abstract

The present application provides a battery pack charging balance control method, device, battery management system and medium. The method includes: when the target battery pack is being charged, obtaining the number of cycles and the charging rate of the current charging and discharging cycle of the target battery pack; and determining at least one balance power parameter corresponding to the number of cycles according to the pre-stored index table, the number of cycles, and the charging rate , the balance power parameter is the power parameter that meets the requirements of the battery management system to control the target battery pack to enter the charging balance mode. The mapping relationship between power parameters; if any current power parameter in the target battery pack is detected to exceed the corresponding balance power parameter, the target battery pack is controlled to enter the charging balance mode to achieve the charging balance of the target battery pack. By adopting the method of the present application, the effect of balanced charging of the battery pack can be improved.

Description

Battery pack charging balance control method, device, battery management system and medium

technical field

The present application relates to battery management technology, in particular to a battery pack charging balance control method, device, battery management system and medium.

Background technique

The printed circuit board of the battery pack usually includes multiple cells. When the battery pack (battery pack is also called battery pack) is charged, due to the slight difference inside the cells, as the battery pack ages, at least one cell will appear. The voltage difference between the voltage of the cell and other cells gradually increases. With the development of battery management technology, in order to improve the safety of battery pack charging, it will control the charging of the battery pack to reach the appropriate voltage, and discharge the relatively fast charging cells to realize the charging of the whole battery pack. balance.

At present, to control the charge balance of the battery pack is to automatically enter the charge balance mode when the battery management system monitors in real time that the current power parameters in the target battery pack exceed the set power parameter threshold, and discharge the above-mentioned batteries with relatively high voltage. , so as to realize the charging balance of the battery pack.

However, as the number of times of use of the battery pack changes, the balance power parameter used as the condition for enabling the charge balance is actually changing. According to the preset power parameter threshold of the battery pack as the condition for entering the charge balance, the effect of the balance charge of the battery pack will be poor.

Contents of the invention

The present application provides a battery pack charging balance control method, device, battery management system and medium to solve the technical problem in the prior art that the charging effect of the battery pack is poor.

In a first aspect, the present application provides a battery pack charging balance control method, which is applied to a battery management system, and the method includes:

When the target battery pack is charging, the number of cycles and the charge rate of the current charge and discharge cycle of the target battery pack are obtained. frequency;

According to the pre-stored index table, the number of cycles and the charging rate, determine at least one balance power parameter corresponding to the number of cycles, the balance power parameter is to satisfy the battery management system to control the target battery pack to enter charging The power parameters of the balance mode, the index table stores the mapping relationship between the charge rate, the number of cycles and each balance power parameter during the actual charge and discharge cycle of the control battery pack consistent with the model of the target battery pack;

If it is detected that any current power parameter in the target battery pack exceeds the corresponding balance power parameter, the target battery pack is controlled to enter a charge balance mode, so as to realize charge balance of the target battery pack.

In the second aspect, the present application provides a battery pack charging balance control device, located in the battery management system, including:

The number of times and the rate acquisition module are used to obtain the number of cycles and the charge rate of the current charge and discharge cycle of the target battery pack when the target battery pack is charging, and the number of cycles refers to charging the battery pack from zero to full Electricity, the number of times to redischarge to zero electric quantity;

A balance voltage value determination module, configured to determine at least one balance power parameter corresponding to the number of cycles according to the pre-stored index table, the number of cycles, and the charging rate, the balance power parameter is to satisfy the requirement of the battery management system Controlling the power parameters of the target battery pack to enter the charging balance mode, the index table stores the relationship between the charging rate, the number of cycles, and the balance power parameters of the control battery pack that is consistent with the model of the target battery pack during the actual charge-discharge cycle. The mapping relationship between;

A charge balance control module, configured to control the target battery pack to enter a charge balance mode if any current power parameter in the target battery pack is monitored to exceed the corresponding balance power parameter, so as to realize charging of the target battery pack balance.

In a third aspect, the present application provides a battery management system, including: a processor, and a memory communicated with the processor;

the memory stores computer-executable instructions;

The processor executes the computer-implemented instructions stored in the memory to implement the method as described in the first aspect.

In a fourth aspect, the present application provides a computer-readable storage medium, where computer-executable instructions are stored in the computer-readable storage medium, and the computer-executable instructions are used to implement the method as described in the first aspect when executed by a processor .

The battery pack charging balance control method, device, battery management system, and medium provided by the present application obtain the number of cycles and the charging rate of the current charge-discharge cycle of the target battery pack when the target battery pack is charging, and the cycle The number of times refers to the number of times the battery pack is charged from zero power to full power, and then discharged to zero power; according to the pre-stored index table, the number of cycles and the charging rate, at least one balance power corresponding to the number of cycles is determined Parameters, the balance power parameter is a power parameter that satisfies the battery management system to control the target battery pack to enter the charging balance mode, and the index table stores the actual charge of the control battery pack that is consistent with the target battery pack model. The mapping relationship between the charge rate, the number of cycles, and each balance power parameter during the discharge cycle; if any current power parameter in the target battery pack exceeds the corresponding balance power parameter is detected, the target battery pack is controlled to enter charging Balance mode to achieve charge balance of the target battery pack. According to the balanced power parameters in the mapping relationship obtained from the actual charge-discharge cycle, as the condition for controlling the target battery pack to enter the charge balance mode, compared with the prior art that ignores the aging problem of the battery pack, the set power parameter threshold is always used as the control Conditions, this application, based on the actual number of cycles and charging rate, determines the balance power parameters as a way to control the target battery pack to enter the charging balance mode, which is more flexible, so it can effectively improve the effect of achieving balanced charging of the battery pack.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description serve to explain the principles of the application.

FIG. 1 is a diagram of an application scenario for implementing a battery pack charging balance control method according to an embodiment of the present application;

FIG. 2 is a schematic flowchart of a method for realizing battery pack charging balance control according to an embodiment of the present application;

FIG. 3 is a schematic flowchart of a method for realizing battery pack charging balance control according to another embodiment of the present application;

FIG. 4 is a schematic structural diagram of the method for realizing the charge balance control of the battery pack in the present application;

FIG. 5 is a schematic structural diagram of a battery management system used to implement a battery pack charging balance control method.

By means of the above drawings, specific embodiments of the present application have been shown, which will be described in more detail hereinafter. These drawings and text descriptions are not intended to limit the scope of the concept of the application in any way, but to illustrate the concept of the application for those skilled in the art by referring to specific embodiments.

Detailed ways

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with aspects of the present application as recited in the appended claims.

First, the nouns involved in this application are explained:

Battery pack: It is a battery pack assembled by welding. It is obtained by welding and fixing many batteries in series or in parallel through welding equipment, and then assembling the battery protection board, battery fixing bracket, battery case and other accessories. After the assembly is completed, it can be Connect the electrical equipment to charge and discharge the electrical equipment.

In order to clearly understand the technical solutions of the present application, the solutions of the prior art are first introduced in detail.

In the traditional way, to control the charge balance of battery packs is to automatically enter the charge balance mode when the battery management system monitors in real time that the current power parameters in the target battery pack exceed the set power parameter threshold. Discharge is performed to achieve charge balance of the battery pack.

However, as the number of times of use of the battery pack changes, the balance power parameter used as the condition for enabling the charge balance is actually changing. Using the preset power parameter threshold of the battery pack as the condition for entering the charging balance will make the effect of the charging balance of the battery pack poor.

Therefore, when faced with the technical problems of the prior art, the inventor found through creative research that in order to improve the charging balance effect of the battery pack. Therefore, according to the mapping relationship between the charging rate obtained during the actual charge and discharge cycle of the control battery pack consistent with the model of the target battery pack, the number of cycles and each balance power parameter, and the number of cycles and the charging rate of the current target battery pack when charging , to determine at least one balance power parameter corresponding to the number of cycles of the target battery pack. When the battery management system detects that any current power parameter of the target battery pack exceeds the corresponding balance power parameter, the battery management system controls the target battery pack to enter the charging balance mode to achieve balanced charging of the target battery pack. According to the balanced power parameters in the mapping relationship obtained from the actual charge-discharge cycle, as the condition for controlling the target battery pack to enter the charge balance mode, compared with the prior art that ignores the aging problem of the battery pack, the set power parameter threshold is always used as the control Conditions, this application, based on the actual number of cycles and charge rate, determines the balance power parameters as a way of controlling the target battery pack to enter the charge balance mode, which is more flexible, so it can effectively improve the effect of realizing the charge balance of the battery pack.

As shown in Figure 1, the application scenario of the battery pack charging balance control method provided by the embodiment of the present application, in this application scenario, the corresponding network architecture includes a battery management system 10 and a target battery pack 20, and the battery management system 10 can be used to control The target battery pack 20 is charged and discharged. In the process of controlling the charging of the target battery pack 20, if the number of cycles and the charging rate of the current charge and discharge cycle of the target battery pack 20 are monitored, it will be stored in the battery management system 10 in advance. The index table is queried to determine at least one balance power parameter corresponding to the current cycle number of the target battery pack 20 . If it is detected that any current power parameter in the target battery pack 20 exceeds its corresponding balance power parameter, then it is determined that the target battery pack 20 satisfies various conditions for controlling the entry into the charge balance mode at the same time, and the target battery pack 20 can be controlled to enter the charge balance mode. mode to achieve balanced charging of the target battery pack 20 .

The technical solution of the present application and how the technical solution of the present application solves the above technical problems will be described in detail below with specific embodiments. The following specific embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below in conjunction with the accompanying drawings.

FIG. 2 is a battery pack charge balance control method provided by an embodiment of the present application. As shown in FIG. 2 , the battery pack charge balance control method provided by this embodiment is executed by a battery management system. Then the battery pack charge balance control method provided in this embodiment includes the following steps:

Step 101, when the target battery pack is charging, obtain the number of cycles and charge rate of the current charge and discharge cycle of the target battery pack, the number of cycles refers to charging the battery pack from zero power to full power, and then discharging to Number of zero charges.

Wherein, the target battery pack refers to the battery pack that is controlled by the battery management system to achieve charging balance during the current charging process. A charge-discharge cycle refers to the complete process of charging the battery pack from zero to full, and then discharging from full to zero. The number of cycles refers to the number of times the battery pack is charged from zero to full and then discharged to zero.

The charging rate refers to the multiple of the actual charging current compared to the standard charging current. Charging the charging pack according to the charging current of the charging rate refers to multiplying the charging rate by the standard charging current as the actual charging current to charge the battery pack. For example, the standard charging current is 1 ampere, and the charging rate of 0.5 times refers to charging the charging pack according to the charging current of 0.5 amperes.

The battery management system can record the number of charge and discharge cycles of the battery pack, which can be recorded through a logic processing unit or a data storage hardware circuit. When the target charging pack is just starting to charge, or during the charging process, the battery management system can obtain the current number of charge and discharge cycles of the target battery pack.

Step 102: Determine at least one balance power parameter corresponding to the number of cycles according to the pre-stored index table, the number of cycles, and the charging rate.

Wherein, the balance power parameter is a power parameter that satisfies the battery management system's need to control the target battery pack to enter the charging balance mode. Optionally, the balance power parameter includes at least one of a balance voltage value and a balance voltage difference. The balance voltage value refers to the voltage value that reaches the control target battery pack to enter the charging balance. The balance voltage difference refers to the voltage difference that reaches the control target battery pack to enter the charging balance.

The index table is constructed from the test data obtained during the actual charge and discharge cycle of the battery pack other than the target battery pack. The index table stores the mapping relationship between the charging rate, the number of cycles and each balance power parameter. That is, the index table stores the mapping relationship between the charging rate, the number of cycles, and each balance power parameter of the control battery pack that is consistent with the model of the target battery pack during the actual charge-discharge cycle.

The control battery pack refers to the battery pack used to construct the index table, which should be the same model as the target battery pack. Because only the battery packs of the same type have relatively small differences in internal structure, it will be relatively more accurate to apply the experimental data of the control battery pack to control the charge balance of the target battery pack.

Step 103, if it is detected that any current power parameter in the target battery pack exceeds the corresponding balance power parameter, control the target battery pack to enter a charging balance mode, so as to realize balanced charging of the target battery pack.

Wherein, the power parameter is a parameter related to power, and may include a voltage value, a voltage difference, and the like. The current power parameter refers to the power parameter corresponding to the target battery pack at the current moment during the actual charge and discharge cycle. The charge balance mode is the working mode in which the target battery pack enters the charge balance mode. After the battery management system controls the target battery pack to enter the charge balance mode, it regulates the cell voltage inside the target battery pack to achieve the charge balance of the target battery pack.

Usually, the condition for enabling charging balance is that each power parameter needs to satisfy the corresponding balance power parameter at the same time. The mapping relationship of the index table in this embodiment is to compare other balance power parameters determined according to one of the balance power parameters when the battery pack is charged and discharged each time. Therefore, entering the charging balance according to any balance power parameter can ensure that other power parameters simultaneously meet and exceed the corresponding balance power parameter.

When the battery management system detects that any current power in the target battery pack exceeds the corresponding balance power parameter, for example, the current voltage value exceeds the balance voltage value, or the current voltage difference exceeds the balance voltage difference, the battery management system controls the target The battery pack enters the charge balance mode, and during the process of entering the charge balance mode, the balanced charge of the target battery pack can be achieved by regulating the voltage of the internal cells of the target battery pack.

In the present application, when the target battery pack is being charged, the number of cycles and the charging rate of the current charge and discharge cycle of the target battery pack are obtained. The number of cycles refers to charging the battery pack from zero power to full power, and then discharging The number of times to zero power; according to the pre-stored index table, the number of cycles, and the charging rate, determine at least one balance power parameter corresponding to the number of cycles, the balance power parameter is to meet the control requirements of the battery management system The target battery pack enters the power parameters of the charging balance mode, and the index table stores the relationship between the charging rate, the number of cycles, and the balance power parameters of the control battery pack that is consistent with the target battery pack model during the actual charge-discharge cycle. Mapping relationship; if any current power parameter in the target battery pack is monitored to exceed the corresponding balance power parameter, control the target battery pack to enter a charging balance mode to achieve balanced charging of the target battery pack. According to the balanced power parameters in the mapping relationship obtained from the actual charge-discharge cycle, as the condition for controlling the target battery pack to enter the charge balance mode, compared with the prior art that ignores the aging problem of the battery pack, the set power parameter threshold is always used as the control Conditions, this application, based on the actual number of cycles and charge rate, determines the balance power parameters as a way of controlling the target battery pack to enter the charge balance mode, which is more flexible, so it can effectively improve the effect of realizing the charge balance of the battery pack.

To further understand the existing technology, the power parameter thresholds for controlling battery pack charge balance usually include a set voltage threshold and a set voltage difference threshold. When the two power parameter thresholds are met at the same time, the battery management system will control the battery pack to enter the charge balance mode. . For example, if the battery management system detects in real time that the minimum voltage value of the cells inside the battery pack exceeds the set voltage threshold, and the voltage difference between the cells inside the battery pack exceeds the set voltage difference threshold, the battery pack will be controlled to Enter the charging balance mode, and discharge the cells with relatively high internal voltage of the battery pack, so as to realize the charging balance of the battery pack. As the battery pack will gradually age during use, as the aging continues, the SOC (state of charge) of the battery pack will gradually decrease, so that the balance voltage value used to turn on the charge balance mode will also gradually decrease, and the balance voltage voltage will gradually decrease. The difference will gradually increase. The original set voltage threshold and set differential pressure threshold can no longer meet the needs of aging battery packs. If you continue to use the set voltage threshold and set differential pressure threshold control as the conditions for entering charge balance, it will Reduce the effect of the battery pack to achieve charge balance.

As the aging of the target battery pack deepens, the balance voltage value will gradually decrease. In this application, based on this law, when the target battery pack is controlled to enter the charging balance mode, it is controlled according to the actual measured balance voltage value corresponding to the number of cycles, so that the target battery pack can be balanced even smaller than the set voltage threshold. The voltage value enters the charging balance mode. Because this application charges from a smaller balance voltage value to the voltage value corresponding to the maximum SOC value, the existing technology is to charge from the set voltage threshold to the voltage value corresponding to the SOC maximum value, therefore, the target battery pack in this application is in the The duration of the charging balance mode is longer, which is equivalent to prolonging the time for achieving balanced charging in the prior art, so that a better balanced charging effect can be obtained.

As an optional implementation manner, in this embodiment, before step 101, the following steps are further included:

In step 201 , obtain at least one balanced power parameter corresponding to multiple charging and discharging cycles of a plurality of comparison battery packs with different rates, and construct an obtained index table.

Specifically, when constructing the index table, multiple charge-discharge cycle experiments are carried out for multiple control battery packs with different rates, so that the corresponding balanced power parameters of the control battery packs with different rates under different cycle times can be obtained, that is, the aforementioned mapping relationship.

Step 202, storing the index table in the battery management system.

Wherein, after the index table is constructed, it can be stored in the battery management system. After the storage, when the charging of the target battery pack is monitored, at least one corresponding balance power parameter can be determined according to its current cycle number and charging rate. In addition, it can also be stored on a storage medium, so that the index table can be copied to other battery management systems for use later.

In this embodiment, at least one balance power parameter corresponding to multiple charge-discharge cycles of a plurality of comparison battery packs with different rates is respectively obtained, and an index table is constructed; and the index table is stored in the battery management system. Since the index table is obtained according to multiple charging and discharging cycles of the control battery packs with different rates, the accuracy of the reference of the target battery pack is relatively high.

When constructing the index table, as an optional implementation, in this embodiment, step 201, specifically for the comparison battery packs of each rate, executes the following steps 301-303 until the control batteries of each rate After the package is executed, the index table is constructed and obtained:

In step 301, the battery pack curve corresponding to each charging and discharging cycle of the control battery pack of the rate is obtained.

Wherein, the battery pack curve is the curve of the voltage value of the control battery pack representing the rate changing with time during each charge-discharge cycle. The number of charge and discharge cycles can be the maximum number of charge and discharge cycles within the entire life cycle of the control battery pack.

For example, in the whole life cycle of the control battery pack, the maximum number of charge-discharge cycles is 200, then the battery pack curves corresponding to the 200 charge-discharge cycles of the control battery pack at this rate can be obtained.

The battery management system presets the sampling time interval, and collects and records the voltage value of the control battery pack during each charge and discharge cycle according to the sampling time interval, so as to obtain the battery pack curve corresponding to the control battery pack in this charge and discharge cycle. This is also the specific way to obtain the battery pack curve corresponding to each charge and discharge cycle of the control battery pack of the rate.

Step 302, determining the balance voltage value corresponding to each of the battery pack curves.

Wherein, each battery pack curve has a unique balance voltage value.

Step 303 , determining the voltage difference corresponding to each balance voltage value as the balance voltage difference corresponding to each charge-discharge cycle of the control battery pack of the rate.

Specifically, for the comparison battery pack of the rate, when a corresponding balance voltage value is obtained for each charging and discharging cycle, a corresponding balance voltage difference is determined according to the balance voltage value. The balanced voltage difference is a voltage difference corresponding to the balanced voltage value.

In this embodiment, for the control battery packs of each rate, the following operations are performed until the control battery packs of each rate are executed, and then an index table is constructed: obtain the battery corresponding to the control battery pack of the rate in each charge and discharge cycle Pack curve, the battery pack curve is the curve of the voltage value of the control battery pack that characterizes the magnification over time during each charge and discharge cycle; determine the equilibrium voltage value corresponding to each of the battery pack curves; The voltage difference corresponding to the balance voltage value is determined as the balance voltage difference corresponding to each charge-discharge cycle of the control battery pack of the rate. Since the balance voltage difference is determined according to the corresponding balance voltage value, when the target battery pack can meet the balance voltage value, the corresponding balance voltage difference can be satisfied at the same time, that is, the condition for entering the charging balance mode can be satisfied at the same time.

As an optional implementation, in this embodiment, step 301, specifically for each charge and discharge cycle of the control battery pack with this rate, execute the following steps 401-403 until the control battery pack with this rate is obtained The battery pack curve corresponding to each charge and discharge cycle:

Step 401 , acquiring the cell curve corresponding to each of the cells in the comparison battery pack with the ratio in this charging and discharging cycle.

Among them, the cell curve is a curve representing the change of the voltage value of the cell with time during each charge and discharge cycle. For each cell in the battery pack, there is a corresponding cell curve during each charge and discharge cycle.

As mentioned above, the battery management system presets the sampling time interval, and collects and records the voltage value of the control battery pack during each charge and discharge cycle according to the sampling time interval, so as to obtain the battery voltage corresponding to the control battery pack in this charge and discharge cycle. Package Curve. More specifically, the battery management system collects and records the voltage value of each battery cell in the control battery pack during each charge-discharge cycle according to a preset sampling time interval. The battery curve corresponding to the battery cell in this charge and discharge cycle, and then determine a cell curve from each cell curve, as the battery pack curve of the control battery pack in this charge and discharge cycle at this rate.

Step 402 , according to a plurality of consecutive first voltage differences that enter the rising region in any cell curve, obtain the balance voltage value of this charging and discharging cycle.

Wherein, for any cell curve, the first voltage difference is the voltage difference obtained by subtracting the voltage at the next time point of the two adjacent time points in the cell curve from the voltage at the previous time point. The rising region is the region corresponding to the first voltage difference greater than the preset difference in the cell curve, and it is also the region where the balanced voltage value is most likely to appear. The balanced voltage value of the target battery pack usually appears in the rising region where the voltage starts to change sharply. Therefore, the balanced voltage value corresponding to each charge-discharge cycle can be found according to a plurality of consecutive first voltage differences in the rising region.

The preset difference is preset and can be used as a threshold for judging whether the cell curve enters the rising zone. When a set number of consecutive first voltage differences greater than the preset difference begin to appear in the cell curve, it is determined that the cell curve changes from the first first voltage difference greater than the preset difference (corresponding to the subsequent A point in time) and entered the rising zone.

For example, if the preset difference is 0.06 millivolts, and there are 10 consecutive first voltage differences greater than 0.06 millivolts in the cell curve, it is considered to enter the rising zone from the first first voltage difference.

According to the continuous multiple first voltage differences that enter the rising area in the curves of each cell, the largest first voltage difference can be determined from each first voltage difference, and the control battery pack with this rate can be determined in this charging and discharging cycle. when the corresponding equilibrium voltage value. It is also possible to determine a median from each first voltage difference, and determine the corresponding equilibrium voltage value of the control battery pack of the rate in this charge-discharge cycle according to the median. It is also possible to take an average value for each of the first voltage differences, and determine the corresponding equilibrium voltage value of the control battery pack of the rate in this charge-discharge cycle according to the average value. As long as an accurate balance voltage value can be determined and obtained according to the foregoing first voltage difference values, the specific implementation manner is not specifically limited here.

Since the rising region is the region where the balance voltage value is most likely to appear, determining the balance voltage value of this charge-discharge cycle according to the continuous multiple first voltage differences in the rise region can increase the probability of obtaining the balance voltage value of this charge-discharge cycle Accuracy.

Step 403 , determining the corresponding time when each cell curve reaches the equilibrium voltage value of this charge-discharge cycle.

Wherein, although the equilibrium voltage values reached by each battery cell in different charge-discharge cycles may be different, the equilibrium voltage values achieved in the same charge-discharge cycle are equal. In this charge and discharge cycle, each cell can reach the same equilibrium voltage value, but the difference is that the time to reach the equilibrium voltage value may be different. The reason for the difference is that due to the subtle differences inside the battery cells, there may be a certain voltage difference when the battery pack leaves the factory. During the charge and discharge cycle of the charge and discharge cycle, there will be a sequence when reaching the equilibrium voltage value corresponding to the charge and discharge cycle. Usually, during the charging process of the battery pack, the cells with higher voltage will reach the equilibrium voltage value earlier than the cells with lower voltage.

After the curves of each cell are obtained, the time when the cell curve of each cell reaches the equilibrium voltage value of this charge-discharge cycle can be determined.

In step 403, the cell curve that reaches the equilibrium voltage value of this charge-discharge cycle at the latest is determined as the battery pack curve corresponding to the control battery pack of this rate in this charge-discharge cycle.

Specifically, the cell that reaches the equilibrium voltage value of this charge-discharge cycle at the latest is usually the cell with the lowest voltage in the battery pack. If the cell with the lowest voltage has reached the equilibrium voltage value of this charge-discharge cycle, then The other cells must have reached this equilibrium voltage value. Therefore, taking the cell curve that reaches this charge-discharge cycle at the latest as the battery pack curve corresponding to the control battery pack of this rate in this charge-discharge cycle can ensure that all cells in the control battery pack of this rate have reached The balance voltage value.

It can be understood that in the process of this charge and discharge cycle, the balance voltage value of the cell curve of each cell in this charge and discharge cycle is determined, and then a cell curve is determined from each cell curve as the control battery of the rate The battery pack curve corresponding to the current charge and discharge cycle.

In this embodiment, for each charge and discharge cycle of the control battery pack of the rate, the following operations are performed until the battery pack curve corresponding to each charge and discharge cycle of the control battery pack of the rate is obtained: Obtain the control battery of the rate The cell curve corresponding to each of the cells in the package in this charge-discharge cycle; determine the time corresponding to each of the cell curves reaching the equilibrium voltage value of this charge-discharge cycle; The cell curve of the balance voltage value of the cycle is determined as the battery pack curve corresponding to the control battery pack of this rate in this charge-discharge cycle. For the control battery pack of each rate, according to the cell curve of each battery cell in the control battery pack of the rate obtained during each charge-discharge cycle, determine the time it reaches the equilibrium voltage value of this charge-discharge cycle, and set The cell curve that reaches this charge-discharge cycle at the latest is used as the battery pack curve corresponding to the control battery pack of this rate in this charge-discharge cycle, which can ensure that all cells in the control battery pack of this rate have reached the equilibrium voltage value, thereby improving the accuracy of the battery pack curve.

As an optional implementation manner, in this embodiment, step 402 includes the following steps:

Step 501 , according to a plurality of consecutive first voltage differences entering the rising region in the curve of any cell, obtain a first voltage difference located in the middle of each of the first voltage differences.

Wherein, the first voltage difference is a difference obtained by subtracting the voltage at a later time point from the voltage at a previous time point among two adjacent time points. The first voltage difference in the middle of each first voltage difference may be the median of the first voltage differences, or the first voltage difference in the middle in chronological order, for example, when the cell curve enters the rising zone There are 12 time points, and there are 11 first voltage differences, and the first voltage difference located in the middle of each first voltage difference refers to the sixth first voltage difference in time order.

Step 502, average the voltage at the next time point corresponding to the first voltage difference located in the middle and the voltage at the previous time point to obtain an average value.

Wherein, the first voltage difference in the middle is the first voltage difference in the middle of the first voltage differences. The average value is a value obtained by averaging the voltage at the next time point and the voltage at the previous time point corresponding to the first voltage difference in the middle.

Step 503 , determining the average value as the balance voltage value of this charging and discharging cycle.

In this embodiment, the first voltage difference located in the middle of each of the first voltage differences is obtained according to a plurality of consecutive first voltage differences entering the rising region in each of the core curves; the first voltage located in the middle The voltage at the next time point corresponding to the difference is averaged with the voltage at the previous time point to obtain an average value; the average value is determined as the corresponding equilibrium voltage value during multiple charge-discharge cycles of the control battery pack of this rate . Since the equilibrium voltage value of this charge-discharge cycle is determined by taking the average value of the voltage at the next time point corresponding to the first voltage difference in the middle and the voltage at the previous time point, and taking the first voltage difference in the middle A voltage difference can relatively obtain a more accurate balance voltage value, therefore, the accuracy of the balance voltage value in this charging and discharging cycle can be improved.

As an optional implementation, in this embodiment, step 303, specifically for each charge-discharge cycle of the control battery pack of this rate, performs steps 601-602 until the control battery pack of this rate is obtained. The balance voltage drop corresponding to each charge and discharge cycle:

Step 601, according to any time point at which the equilibrium voltage value of this charge-discharge cycle is obtained, determine the minimum voltage drop of the control battery pack with this rate in this charge-discharge cycle at this time point.

Wherein, any time point may be the previous time point or the subsequent time point of the two adjacent time points for obtaining the equilibrium voltage value of the current charge-discharge cycle.

According to this any time point, compare the cell curves of each cell in the control battery pack with this ratio, obtain the voltage value corresponding to each cell curve at this any point in time, and determine any two cells based on each voltage value The voltage difference between them, from which the minimum voltage difference of the control battery pack with this rate in this charge-discharge cycle at this time point is obtained.

Step 602 , determining the minimum voltage drop as the balance voltage drop corresponding to the control battery pack of the rate in this charge-discharge cycle.

In this embodiment, the following operations are performed for each charge and discharge cycle of the control battery pack of this rate until the equilibrium voltage difference corresponding to each charge and discharge cycle of the control battery pack of this rate is obtained: At any time point of the equilibrium voltage value of the discharge cycle, determine the minimum voltage drop of the control battery pack of this rate in this charge and discharge cycle at this time point; determine the minimum voltage drop as the control battery pack of this rate The balance voltage drop corresponding to this charge-discharge cycle. Since the balance voltage difference is obtained based on the minimum voltage difference determined at the time point when the balance voltage value of this charging and discharging cycle is obtained, therefore, when entering the charging balance mode according to the balance voltage value, it is equivalent to the voltage difference exceeding the corresponding The balanced voltage difference can enter the charge balance mode, and vice versa.

As an optional implementation manner, in this embodiment, step 103, more specifically, may follow the following step 701 or step 702 to control the target battery pack to enter the charging balance mode, wherein:

Step 701, if it is detected that the minimum voltage in the target battery pack exceeds the balance voltage value, control the target battery pack to enter a charging balance mode, so as to realize balanced charging of the target battery pack.

Wherein, the minimum voltage in the target battery pack is the smallest cell voltage among the cell voltages in the target battery pack. If the minimum voltage in the target battery pack exceeds the balance voltage value, the voltages of other cells in the target battery pack must have exceeded the balance voltage value, so when the minimum voltage in the target battery pack exceeds the balance voltage value, control the target battery The battery pack enters charge balance mode to achieve balanced charging of the target battery pack.

Step 702, if it is detected that the minimum voltage difference in the target battery pack exceeds the balanced voltage difference, control the target battery pack to enter a charging balance mode, so as to realize balanced charging of the target battery pack.

Wherein, the minimum voltage difference in the target battery pack refers to the minimum voltage difference between internal cells in the target battery pack. If the minimum voltage drop in the target battery pack exceeds the balance voltage drop, other voltage drops inside the target battery pack must have exceeded the balance voltage drop, so the minimum voltage drop in the target battery pack exceeds the balance voltage drop When , the target battery pack is controlled to enter the charging balance mode, so as to realize the balanced charging of the target battery pack.

In this embodiment, when the battery management system monitors that the minimum voltage in the target battery pack exceeds the balance voltage value, or the minimum voltage difference in the target battery pack exceeds the balance voltage difference, the target battery pack can be controlled to enter the charging balance mode , to achieve the charge balance of the target battery pack.

As an optional implementation manner, in this embodiment, step 103, when controlling the target battery pack to enter the charging balance mode, specifically includes: controlling at least one target battery cell in the target battery pack to connect to a discharge circuit, Discharging the target battery cell while charging the target battery cell.

Wherein, the target cell is the cell whose voltage in the target battery pack is higher than the voltage of the preset number of cells, for example, if the preset number is 2, then the target cell is the voltage in the target battery pack, Select the top 2 batteries.

The discharge circuit may be a load circuit, and the load may only include several thermal resistances. The discharge circuit can be integrated with the target battery pack on a printed circuit board, or it can also be an external circuit. The battery management system can connect to the discharge circuit by controlling the I/O interface of at least one target cell in the target battery pack. After the target cell is connected to the discharge circuit, it can be used as the power supply of the discharge circuit to provide current for it. Taking the thermal resistance as an example, the thermal resistance will generate heat after the circuit is connected, thereby converting electric energy into heat energy to realize the consumption of electric energy.

Discharging the cell with a higher voltage in the target battery pack through the discharge circuit can suppress the voltage increase of the cell with a higher voltage, so that the voltage difference between it and the voltage of other cells can be reduced as much as possible . The process of achieving charge balance can be understood as discharging the cells with higher internal voltage in the battery pack to reduce the voltage difference between the cells inside the battery pack, thereby achieving the balance of the voltage of the internal cells.

While charging the target battery cell, the target battery cell is discharged, and the unit charging current when the target battery cell is charged is greater than the unit discharge current when the target battery cell is discharged. Wherein, the unit charge current refers to the charge current per unit time, and the unit discharge current refers to the discharge current per unit time. For example, the unit charge current of the target cell is 1 ampere per second, and the unit discharge current may be 50 milliamps per second.

For the cells other than the target cells in the target battery pack, they are still charged according to the unit charging current, but not discharged. That is, while the target cell is being discharged, other cells are normally charged.

In this embodiment, at least one target cell in the target battery pack is controlled to be connected to a discharge circuit, and the target cell is charged while discharging the target cell; the target cell is the target cell. For the cells in the battery pack whose voltage is higher than the voltage of the preset number of cells, the unit charge current when charging the target cell is greater than the unit discharge current when the target cell is discharged. By discharging the cell with a higher voltage inside the target battery pack, the voltage difference between the target cell and other cells inside the target battery pack can be reduced as much as possible to achieve balanced charging of the target battery pack.

In one embodiment, when the battery management system is charging the target battery pack, according to the current charging rate and the number of cycles, in order to save the internal data storage space of the battery management system, the voltage value range can be set in the voltage index table , can be determined according to the equal ratio method when looking up the table.

Fig. 4 is a schematic structural diagram of a battery pack charging balance control device provided by an embodiment of the present application. The battery pack charging balance control device 40 includes: a frequency and multiplier acquisition module 41 , a balance voltage value determination module 42 and a charge balance control module 43 . in:

The number of times and the rate of acquisition module 41 is used to obtain the number of cycles and the charge rate of the current charge and discharge cycle of the target battery pack when the target battery pack is charged, and the number of cycles refers to charging the battery pack from zero power to The number of times the battery is fully charged and then discharged to zero;

A balance voltage value determination module 42, configured to determine at least one balance power parameter corresponding to the number of cycles according to the pre-stored index table, the number of cycles and the charging rate, the balance power parameter is to meet the requirements of the battery management The system controls the power parameters of the target battery pack to enter the charging balance mode, and the index table stores the charging rate, cycle times and balance power parameters of the control battery pack that is consistent with the model of the target battery pack during the actual charge and discharge cycle The mapping relationship between;

The charge balance control module 43 is configured to control the target battery pack to enter a charge balance mode if any current power parameter in the target battery pack is detected to exceed the corresponding balance power parameter, so as to realize the charging balance of the target battery pack. Balance charge.

Optionally, the battery pack charge balance control device 40 further includes an index table construction module, configured to: respectively obtain at least one balance power parameter corresponding to multiple charge-discharge cycles of a plurality of different rate control battery packs, and construct an index to obtain table; storing the index table in the battery management system.

Optionally, the balanced power parameter includes at least one of the following parameters: a balanced voltage value and a balanced voltage difference.

Optionally, the index table construction module, when obtaining at least one balanced power parameter corresponding to multiple charging and discharging cycles of the comparison battery packs with different rates, is specifically used for: comparing for each rate when constructing and obtaining the index table For the battery pack, perform the following operations until the control battery packs of each rate are completed, then construct an index table: obtain the battery pack curve corresponding to each charge and discharge cycle of the control battery pack of the rate, and the battery pack curve is each During the secondary charge and discharge cycle, the curve of the voltage value of the control battery pack that characterizes the rate changes with time; determine the balance voltage value corresponding to each of the battery pack curves; determine the voltage difference corresponding to each of the balance voltage values It is the equilibrium voltage drop corresponding to each charge-discharge cycle of the control battery pack of this rate.

Optionally, the comparison battery pack includes a plurality of batteries, and the index table construction module is specifically used for: when obtaining the battery pack curve corresponding to each charge and discharge cycle of the comparison battery pack of the rate: For each charge and discharge cycle of the battery pack, perform the following operations until the battery pack curve corresponding to each charge and discharge cycle of the control battery pack with the rate is obtained: The cell curve corresponding to the charge and discharge cycle; according to the continuous multiple first voltage differences entering the rising area in any cell curve, the balance voltage value of this charge and discharge cycle is obtained; the rising area is the most An area where a balanced voltage value may appear, the first voltage difference is the difference obtained by subtracting the voltage at the next time point from the voltage at the previous time point among two adjacent time points; The corresponding time when the curve reaches the equilibrium voltage value of this charge-discharge cycle; the cell curve that reaches the equilibrium voltage value of this charge-discharge cycle at the latest is determined as the control battery pack with this rate corresponding to the current charge-discharge cycle battery pack curve.

Optionally, when the index table construction module obtains the balance voltage value of this charging and discharging cycle according to a plurality of consecutive first voltage differences entering the rising zone in any cell curve, it is specifically used to: according to any of the For a plurality of consecutive first voltage differences in the cell curve entering the rising region, obtain the first voltage difference located in the middle of each of the first voltage differences; The voltage at the point and the voltage at the previous time point are averaged to obtain an average value; the average value is determined as the equilibrium voltage value of this charge-discharge cycle.

Optionally, the index table construction module, when determining the voltage difference corresponding to each of the balanced voltage values as the balanced voltage difference corresponding to each charging and discharging cycle of the control battery pack of the rate, is specifically used to: For each charge-discharge cycle of the control battery pack of the rate, perform the following operations until the equilibrium voltage drop corresponding to each charge-discharge cycle of the control battery pack of the rate is obtained: At any point in time, determine the minimum voltage drop of the control battery pack of this rate in this charge-discharge cycle; The balance voltage dropout.

Optionally, the charge balance control module 43 controls the target battery pack to enter the charge balance mode if it detects that any current power parameter in the target battery pack exceeds the corresponding balance power parameter, so as to realize the During the balanced charging of the battery pack, it is specifically used for: if it is detected that the minimum voltage in the target battery pack exceeds the balance voltage value, then control the target battery pack to enter the charging balance mode to achieve the balance of the target battery pack Charging; or, if it is detected that the minimum voltage difference in the target battery pack exceeds the balanced voltage difference, then controlling the target battery pack to enter a charging balance mode to achieve balanced charging of the target battery pack.

Optionally, when the charge balance control module 43 controls the target battery pack to enter the charge balance mode, it is specifically used to: control at least one target battery cell in the target battery pack to connect to the discharge circuit, Discharging the target cell while charging; the target cell is a cell whose voltage in the target battery pack is higher than the voltage of the preset number of cells, and the unit charging current of the target cell when charging is greater than the unit discharge current when the target cell is discharged.

Fig. 5 is a block diagram of a battery management system according to an exemplary embodiment. The device may be, as shown in Fig. 5 , the battery management system, including: a memory 51 and a processor 52; A memory for executing instructions; the processor 52 is used to run computer programs or instructions to implement the battery pack charge balance control method provided in any one of the above embodiments.

Among them, the memory 51 is used to store programs. Specifically, the program may include program code, and the program code includes computer operation instructions. The memory 51 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one magnetic disk memory.

Wherein, the processor 52 may be a central processing unit (Central Processing Unit, referred to as CPU), or a specific integrated circuit (Application Specific Integrated Circuit, referred to as ASIC), or is configured to implement one or multiple integrated circuits.

Optionally, in terms of specific implementation, if the memory 51 and the processor 52 are implemented independently, the memory 51 and the processor 52 may be connected to each other through the bus 53 to complete mutual communication. The bus 53 may be an industry standard architecture (Industry Standard Architecture, referred to as ISA) bus 53, a peripheral component interconnection (Peripheral Component, referred to as PCI) bus 53 or an extended industry standard architecture (Extended Industry Standard Architecture, referred to as EISA) bus 53 Wait. The bus 53 can be divided into an address bus 53, a data bus 53, a control bus 53, and the like. For ease of representation, only one thick line is used in FIG. 5 , but it does not mean that there is only one bus 53 or one type of bus 53 .

A non-transitory computer-readable storage medium, when the instructions in the storage medium are executed by the processor of the battery management system, the battery management system can execute the above battery pack charge balance control method of the battery management system.

Other embodiments of the present application will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the application, these modifications, uses or adaptations follow the general principles of the application and include common knowledge or conventional technical means in the technical field not disclosed in the application . The specification and examples are to be considered exemplary only, with a true scope and spirit of the application indicated by the following claims.

It should be understood that the present application is not limited to the precise constructions which have been described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims (12)

1. A battery pack charge balance control method is applied to a battery management system and is characterized by comprising the following steps:

when the target battery pack is charged, acquiring the cycle number and charging multiplying power of the current charging and discharging cycle of the target battery pack, wherein the cycle number refers to the number of times that the battery pack is charged from zero electric quantity to full electric quantity and then discharged to zero electric quantity;

determining at least one balance power parameter corresponding to the cycle number according to a pre-stored index table, the cycle number and the charging rate, wherein the balance power parameter is a power parameter which meets the requirement that the battery management system controls the target battery pack to enter a charge balance mode, and the index table stores the mapping relation among the charging rate, the cycle number and each balance power parameter in actual charge and discharge cycles of a comparison battery pack which is consistent with the model of the target battery pack;

and if any current power parameter in the target battery pack exceeds the corresponding balance power parameter, controlling the target battery pack to enter a charge balance mode so as to realize the balance charging of the target battery pack.

2. The method according to claim 1, before acquiring the number of cycles and the charging rate of the current charge and discharge cycle of the target battery pack when the target battery pack is charged, further comprising:

respectively obtaining at least one balance power parameter corresponding to a plurality of times of charge-discharge cycles of a plurality of comparison battery packs with different multiplying powers, and constructing and obtaining an index table;

and storing the index table in the battery management system.

3. The method of claim 1, wherein the balancing power parameter comprises at least one of: a balance voltage value and a balance voltage difference.

4. The method according to claim 3, wherein the obtaining at least one balance power parameter corresponding to a plurality of charge-discharge cycles of a plurality of control battery packs with different multiplying powers respectively to construct an obtaining index table comprises:

aiming at the comparison battery pack with each multiplying power, the following operations are executed until the comparison battery pack with each multiplying power is executed, and an index table is constructed and obtained:

acquiring a battery pack curve corresponding to the comparison battery pack with the multiplying power in each charge-discharge cycle, wherein the battery pack curve is a curve representing the change of the voltage value of the comparison battery pack with the multiplying power along with time in each charge-discharge cycle process;

determining a balance voltage value corresponding to each battery pack curve;

and determining the voltage difference corresponding to each balance voltage value as the balance voltage difference corresponding to each charge-discharge cycle of the comparison battery pack with the multiplying power.

5. The method of claim 4, wherein the comparison battery pack comprises a plurality of battery cells, and the obtaining of the battery pack curve corresponding to the comparison battery pack of the rate in each charge-discharge cycle comprises:

and aiming at each charge-discharge cycle of the comparison battery pack with the multiplying power, executing the following operations until a battery pack curve corresponding to each charge-discharge cycle of the comparison battery pack with the multiplying power is obtained:

obtaining a cell curve corresponding to each cell in the comparison cell pack with the multiplying power in the current charge-discharge cycle;

obtaining a balance voltage value of the charge-discharge cycle according to a plurality of continuous first voltage difference values entering the uplifting region in any cell curve; the raising area is an area where a balanced voltage value is most likely to appear in the cell curve, and the first voltage difference value is a difference value obtained by subtracting a voltage at a later time point from a voltage at a previous time point in two adjacent time points;

determining the corresponding time when each battery cell curve reaches the balance voltage value of the charge-discharge cycle;

and determining the battery cell curve which reaches the balance voltage value of the charge-discharge cycle at the latest as a battery pack curve corresponding to the charge-discharge cycle of the contrast battery pack with the multiplying power.

6. The method according to claim 4, wherein obtaining the equilibrium voltage value of the current charge-discharge cycle according to a plurality of continuous first voltage difference values entering a raise region in any one of the cell curves comprises:

obtaining a first voltage difference value positioned in the middle of each first voltage difference value according to a plurality of continuous first voltage difference values entering a rising area in any one cell curve;

averaging the voltage of the later time point corresponding to the first voltage difference value in the middle and the voltage of the previous time point to obtain an average value;

and determining the average value as the balance voltage value of the current charge-discharge cycle.

7. The method of claim 5, wherein determining the voltage difference corresponding to each of the equilibrium voltage values as the equilibrium voltage difference corresponding to each charge-discharge cycle of the control battery pack of the rate comprises:

and aiming at each charge-discharge cycle of the comparison battery pack with the multiplying power, executing the following operations until obtaining the balance voltage difference corresponding to each charge-discharge cycle of the comparison battery pack with the multiplying power:

determining the minimum voltage difference of the comparison battery pack with the multiplying power at the time point in the charge-discharge cycle according to any one time point of the obtained balance voltage value of the charge-discharge cycle;

and determining the minimum voltage difference as the balance voltage difference corresponding to the current charge-discharge cycle of the comparison battery pack with the multiplying power.

8. The method according to any one of claims 1-6, wherein if it is monitored that any current power parameter in the target battery pack exceeds the corresponding balance power parameter, controlling the target battery pack to enter a charge balance mode to achieve balanced charging of the target battery pack comprises:

if the minimum voltage in the target battery pack is monitored to exceed the balance voltage value, controlling the target battery pack to enter a charge balance mode so as to realize the balance charging of the target battery pack;

or,

and if the minimum voltage difference in the target battery pack is monitored to exceed the balance voltage difference, controlling the target battery pack to enter a charge balance mode so as to realize the balance charging of the target battery pack.

9. The method of claim 1, wherein the controlling the target battery pack to enter a charge balancing mode comprises:

controlling at least one target battery cell in the target battery pack to be connected with a discharge circuit, and discharging the target battery cell while charging the target battery cell;

the target battery cell is a battery cell with voltage higher than that of preset battery cells in the target battery pack, and the unit charging current of the target battery cell during charging is larger than the unit discharging current of the target battery cell during discharging.

10. A battery pack charge balance control apparatus in a battery management system, the apparatus comprising:

the times and multiplying power acquisition module is used for acquiring the cycle times and the charging multiplying power of the current charging and discharging cycle of the target battery pack when the target battery pack is charged, wherein the cycle times refer to the times of charging the battery pack from zero electric quantity to full electric quantity and then discharging the battery pack to zero electric quantity;

the balance voltage value determining module is used for determining at least one balance power parameter corresponding to the cycle number according to a pre-stored index table, the cycle number and the charging rate, wherein the balance power parameter is a power parameter which meets the requirement that the battery management system controls the target battery pack to enter a charging balance mode, and the index table stores the mapping relation among the charging rate, the cycle number and each balance power parameter in actual charging and discharging cycles of a comparison battery pack which is consistent with the model of the target battery pack;

and the charge balance control module is used for controlling the target battery pack to enter a charge balance mode to realize charge balance of the target battery pack if any current power parameter in the target battery pack exceeds the corresponding balance power parameter.

11. A battery management system, comprising: a processor, and a memory communicatively coupled to the processor;

the memory stores computer-executable instructions;

the processor executes computer-executable instructions stored by the memory to implement the method of any of claims 1-9.

12. A computer-readable storage medium having computer-executable instructions stored therein, which when executed by a processor, are configured to implement the method of any one of claims 1-9.

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