CN113733980B - Method, device, medium and electronic equipment for determining power battery capacity - Google Patents

Abstract

The present disclosure relates to a method, apparatus, medium, and electronic device for determining power battery capacity. The method comprises the following steps: acquiring charging current corresponding to each charging time of the power battery in the historical charging process; determining current stabilization stages in a historical charging process according to charging currents corresponding to all charging moments, wherein the change value of the charging current does not exceed a preset current change threshold value in a charging time period corresponding to each current stabilization stage; determining a target current stabilization stage from the current stabilization stages; and determining the capacity of the power battery according to the charging current and the charging voltage corresponding to each charging moment in the target current stable stage. Therefore, data can be screened, a stage in which the data change steadily is screened out, and the capacity of the power battery is determined by using the data in the stage, so that the capacity of the power battery can be determined accurately even in a low-frequency acquisition scene.

Description

Method, device, medium and electronic equipment for determining power battery capacity

technical field

The present disclosure relates to the field of vehicles, in particular, to a method, device, medium and electronic equipment for determining the capacity of a power battery.

Background technique

With the gradual popularization of electric vehicles, the performance and status of batteries are becoming more and more important as a part of the three electric systems. Battery life is an important part of the process of research and development of batteries and power battery packs, and battery life is also one of the indicators for evaluating the pros and cons of power battery packs. Therefore, the prediction of power battery capacity is the focus of electric vehicle research, and it has high significance for battery cell research and development. In related technologies, the battery state parameters are generally obtained through online data, and the actual cumulative charge and discharge capacity is obtained by using methods such as ampere-hour integration, and then the estimated value is obtained, and then the error between the actual value and the estimated value is corrected to obtain the cell state estimation parameters . However, this method requires high data accuracy, and is only applicable to high-frequency acquisition scenarios, and cannot be applied to low-frequency acquisition data.

Contents of the invention

The purpose of the present disclosure is to provide a method, device, medium and electronic equipment for determining the capacity of a power battery, so as to accurately determine the capacity of the power battery.

In order to achieve the above object, according to the first aspect of the present disclosure, a method for determining the capacity of a power battery is provided, the method comprising:

Obtain the charging current corresponding to each charging moment of the power battery in the historical charging process;

According to the charging current corresponding to each charging moment, determine the current steady stage in the historical charging process, wherein, in the charging period corresponding to each said current steady stage, the change value of the charging current does not exceed a preset current change threshold;

determining a target current steady stage from the current steady stage;

The capacity of the power battery is determined according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage.

Optionally, the determining the target current steady stage from the current steady stage includes:

According to the charging current corresponding to each charging moment in each current steady stage, determine the charged electric quantity corresponding to each current steady stage;

The current steady stage corresponding to the charged electric quantity with the largest electric quantity value is taken as the target current steady stage.

Optionally, the charged electric quantity corresponding to the current steady stage is determined by the following method:

Among them, Ah(k) is the charged electricity at the kth charging moment of the current steady stage, t(k) is the initial charging moment of the current steady stage, and t(k+1) is the current steady state The charging time at the end of the stage, I(k) is the charging current at the time t(k).

Optionally, the determining the capacity of the power battery according to the charging current and charging voltage corresponding to each charging moment in the stable stage of the target current includes:

Determine the target charging SOC corresponding to the charging voltage at the target charging time according to the preset correspondence between the voltage and the SOC, wherein the target charging time is one of the charging times in the target current steady stage;

Determine the target charged electricity corresponding to the target charging moment;

The capacity of the power battery is determined according to the initial SOC of the power battery in the historical charging process, the target charging SOC and the target charged power.

Optionally, the capacity of the power battery is determined in the following manner:

Calculate the i-th iteration through the following formula to obtain the battery capacity Ah_cell(i) corresponding to the i-th iteration:

Ah_cell(i)=Ah_cell(i-1)+k(i)*ε(i)

Among them, Ah_cell(i-1) is the battery capacity calculated in the i-1th time, k(i) is the gain coefficient corresponding to the i-th iteration, and ε(i) is the estimation error corresponding to the i-th iteration;

When i reaches the preset number of times, or when the battery capacity corresponding to the i-th iteration converges, the battery capacity corresponding to the i-th iteration is determined as the capacity of the power battery.

Optionally, the gain coefficient k(i) is determined by the following formula:

Among them, P(i-1) is the iterative calculation coefficient corresponding to the target charging time, λ is the forgetting factor, and x(i) is determined by the following formula:

x(i)=SOC(i)-SOC(a)

Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC.

Optionally, the estimation error ε(i) is determined by the following formula:

ε(i)=Ah(i)-Ah_cell(i-1)*x(i)

Among them, Ah(i) is the charged power of the target, and x(i) is determined by the following formula:

x(i)=SOC(i)-SOC(a)

Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC.

According to a second aspect of the present disclosure, there is provided a device for determining the capacity of a power battery, the device comprising:

An acquisition module, configured to acquire the charging current corresponding to each charging moment of the power battery during the historical charging process;

The first determination module is used to determine the current steady stage in the historical charging process according to the charging current corresponding to each charging moment, wherein, in the charging period corresponding to each of the current steady stages, the change value of the charging current does not exceed the preset The set current change threshold;

The second determining module is used to determine the target current steady stage from the current steady stage;

The third determining module is configured to determine the capacity of the power battery according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage.

Optionally, the second determination module includes:

The first determining sub-module is used to determine the charged electric quantity corresponding to each current steady stage according to the charging current corresponding to each charging moment in each current steady stage;

The second determination sub-module is configured to use the current steady stage corresponding to the charged electric quantity with the largest electric quantity as the target current steady stage.

Optionally, the first determining submodule is used to determine the charged electric quantity corresponding to the steady state of the current in the following manner:

Among them, Ah(k) is the charged electricity at the kth charging moment of the current steady stage, t(k) is the initial charging moment of the current steady stage, and t(k+1) is the current steady state The charging time at the end of the stage, I(k) is the charging current at the time t(k).

Optionally, the third determination module includes:

The third determination sub-module is used to determine the target charging SOC corresponding to the charging voltage at the target charging time according to the preset correspondence between the voltage and the SOC, wherein the target charging time is the charging in the target current steady stage one of the moments;

The fourth determining submodule is used to determine the target charged electric quantity corresponding to the target charging moment;

The fifth determination sub-module is used to determine the capacity of the power battery according to the initial SOC of the power battery in the historical charging process, the target charging SOC and the target charged power.

Optionally, the fifth determining submodule is used to determine the capacity of the power battery in the following manner:

Calculate the i-th iteration through the following formula to obtain the battery capacity Ah_cell(i) corresponding to the i-th iteration:

Ah_cell(i)=Ah_cell(i-1)+k(i)*ε(i)

Among them, Ah_cell(i-1) is the battery capacity calculated in the i-1th time, k(i) is the gain coefficient corresponding to the i-th iteration, and ε(i) is the estimation error corresponding to the i-th iteration;

When i reaches the preset number of times, or when the battery capacity corresponding to the i-th iteration converges, the battery capacity corresponding to the i-th iteration is determined as the capacity of the power battery.

Optionally, the gain coefficient k(i) is determined by the following formula:

Among them, P(i-1) is the iterative calculation coefficient corresponding to the target charging time, λ is the forgetting factor, and x(i) is determined by the following formula:

x(i)=SOC(i)-SOC(a)

Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC.

Optionally, the estimation error ε(i) is determined by the following formula:

ε(i)=Ah(i)-Ah_cell(i-1)*x(i)

Among them, Ah(i) is the charged power of the target, and x(i) is determined by the following formula:

x(i)=SOC(i)-SOC(a)

Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC.

According to a third aspect of the present disclosure, there is provided a computer-readable storage medium on which a computer program is stored, and when the program is executed by a processor, the steps of the method described in the first aspect of the present disclosure are implemented.

According to a fourth aspect of the present disclosure, there is provided an electronic device, comprising:

a memory on which a computer program is stored;

A processor configured to execute the computer program in the memory to implement the steps of the method described in the first aspect of the present disclosure.

Through the above technical solution, the charging current corresponding to each charging moment of the power battery in the historical charging process is obtained; according to the charging current corresponding to each charging moment, the current steady stage in the historical charging process is determined, wherein, in each current steady stage The corresponding During the charging period, the change value of the charging current does not exceed the preset current change threshold; the target current steady stage is determined from the current steady stage; according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage, the power battery is determined capacity. In this way, the data can be screened, the stage in which the data changes steadily, and the data in this stage can be used to determine the capacity of the power battery, so that even in low-frequency acquisition scenarios, the capacity of the power battery can be determined more accurately .

Other features and advantages of the present disclosure will be described in detail in the detailed description that follows.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present disclosure, and constitute a part of the description, together with the following specific embodiments, are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the attached picture:

Fig. 1 is a flowchart of a method for determining the capacity of a power battery according to an embodiment of the present disclosure;

Fig. 2 is an exemplary flow chart of the steps of determining the target current steady stage from the current steady stage in the method for determining the capacity of a power battery according to the present disclosure;

Fig. 3 is an exemplary flow chart of the steps of determining the capacity of the power battery according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage in the method for determining the capacity of the power battery according to the present disclosure;

Fig. 4 is a block diagram of a device for determining the capacity of a power battery according to an embodiment of the present disclosure.

detailed description

Specific embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

Before introducing the solutions of the present disclosure, the application background of the present disclosure will be described first. As mentioned in the background art, the prediction of the power battery capacity is of great significance.

There are many methods for battery capacity estimation, such as open circuit voltage method, ampere-hour integration method, and neural network method. Since it is difficult to obtain the static voltage in a real vehicle, and the SOC estimation is easily affected by temperature, the open circuit voltage method is not suitable for the capacity estimation of the vehicle power battery. The ampere-hour integration method has extremely high requirements on equipment accuracy and SOC estimation accuracy. Neural network rules require a large number of samples for calculation and are prone to distortion.

During the operation of the vehicle, the data collected by the BMS (Battery Management System, battery management system) will be uploaded to the vehicle cloud platform through the T-box. Due to equipment limitations, some data collected by the BMS cannot be uploaded at high frequency , After the data is processed by the BMS, it changes from short-time interval high-frequency data to long-time low-frequency data, and then uploads to the cloud platform. The current capacity prediction algorithm has high requirements on data accuracy and cannot cope with battery capacity prediction in low-frequency acquisition scenarios.

In order to solve the above problems, the present disclosure provides a method, device, medium and electronic equipment for determining the capacity of the power battery, so as to accurately determine the capacity of the power battery, especially in the scene of low-frequency data collection.

Fig. 1 is a flowchart of a method for determining the capacity of a power battery according to an embodiment of the present disclosure. As shown in Fig. 1 , the method may include the following steps.

In step 11, the charging current corresponding to each charging moment in the historical charging process of the power battery is obtained.

Here, the historical charging process corresponds to one historical charging process. If there are multiple historical charging process data, each historical charging process can be processed by referring to the processing method of one historical charging process.

The battery management system BMS of the vehicle can collect data related to the battery and upload it to the cloud platform connected to the vehicle. The data related to the battery may include: current, voltage, SOC, time (eg, charging start time, charging end time, etc.), charging status (eg, start charging, end charging). The BMS can collect these data periodically, and determine the current, voltage, SOC, and charging state corresponding to each collection moment, and, during the charging process of the power battery, the collection moment can correspond to the charging moment in step 11.

For example, the charging current corresponding to each charging moment in the historical charging process can be obtained directly through the BMS of the own vehicle. For another example, the charging current corresponding to each charging moment in the historical charging process can be obtained through the cloud platform connected to the vehicle.

In addition, since determining the battery capacity requires certain preconditions, that is, not any charging process data can be used to predict the battery capacity, so a certain degree of screening is required to screen out the batteries that can be used to determine the power battery flux. The historical charging process, and determine the power battery capacity based on the data in the historical charging process. Therefore, the historical charging process needs to meet one of the most basic conditions, that is, the difference between the SOC at the end of charging and the SOC at the beginning of charging in the historical charging process should be greater than the preset charging capacity (can be set according to empirical values) , so that the data can be used to determine the battery capacity, otherwise, even if such data is used, the determined power battery capacity is not accurate and has no reference value. Therefore, based on multiple charging processes, the corresponding SOC (SOC1) at the beginning of each charging process can be obtained, and the corresponding SOC (SOC2) at the end of each charging process can be obtained. When (SOC2-SOC1) is greater than the preset charging capacity , the charging process can be used as the historical charging process.

In step 12, according to the charging current corresponding to each charging moment, the current steady stage in the historical charging process is determined.

Wherein, in the charging period corresponding to each current steady stage, the change value of the charging current does not exceed a preset current change threshold.

For example, the initial moment of the historical charging process can be taken as the starting point of time, the current is obtained one by one according to the advancement of time, and the difference between the charging current at each charging moment relative to the starting point of time can be calculated in real time. When a certain charging moment is calculated, When the current difference exceeds the preset difference threshold, the period from the start of time to the charging moment is taken as the current steady stage. In the follow-up, it is also possible to continue to use this charging moment as the time starting point, and continue to determine other stable current stages in the historical charging process in the above manner.

For another example, on the basis of the above example, the minimum duration corresponding to the current steady stage may also be specified. That is to say, on the premise of satisfying the requirement of stable current value, the determined current stable stage needs to reach a sufficient duration. For example, if the preset shortest duration is 1 s, if the current is stable between 0.05 s and 1 s, considering the insufficient duration, this period cannot be regarded as the current stable stage. In this way, the duration of the stable current phase can be guaranteed, thereby ensuring that the current stable phase has a sufficient amount of data for determining the capacity of the power battery.

In step 13, the target current steady stage is determined from the current steady stage.

In a possible implementation manner, step 13 may include the following steps, as shown in FIG. 2:

In step 21, according to the charging current corresponding to each charging moment in each current steady stage, determine the charged electric quantity corresponding to each current steady stage;

In step 22, the current steady stage corresponding to the charged electric quantity with the largest electric quantity value is taken as the target current steady stage.

For example, the charged electric quantity corresponding to the current steady stage can be determined in the following manner:

Among them, Ah(k) is the charged electricity at the kth charging moment in the current steady stage, t(k) is the initial charging moment of the current steady stage, t(k+1) is the end charging moment of the current steady stage, I(k) is the charging current at time t(k), and k is a positive integer greater than or equal to 1.

Thus, the charged electric quantity corresponding to each current steady stage in the historical charging process can be determined, and thus, the current steady stage corresponding to the largest charged electric quantity can be used as the target current steady stage. In this way, the capacity of the power battery is determined by using the stable stage of the target current with the largest change in power, and the data is more abundant, which is convenient for obtaining more accurate calculation results.

In addition, since the determination of the battery capacity requires certain prerequisites, that is, not any data in the steady current stage can be used to predict the battery capacity, so the target current steady stage also needs to meet some basic conditions. For example, the voltage in the steady stage of the target current should include the minimum voltage (which can be set according to the empirical value) and the highest voltage (which can be set according to the empirical value) required by the judgment current steady stage. For another example, the charged electric quantity corresponding to the steady stage of the target current should be greater than the minimum capacity required to predict the battery capacity. Exemplarily, a certain degree of screening can be carried out according to the above conditions before step 21 is executed, so as to screen out alternative current steady stages, and select target current steady stages from these alternative current steady stages based on steps 21 and 22 stage. For another example, screening can be carried out during the execution of steps 21 and 22. For example, when finding the maximum charged power, combine the above-mentioned requirements of the highest voltage and the lowest voltage, and only take out the current steady stage that meets the voltage requirements. The maximum charged power, and the maximum charged power found should be greater than the minimum capacity required to predict the battery capacity.

In step 14, the capacity of the power battery is determined according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage.

In a possible implementation manner, step 14 may include the following steps, as shown in FIG. 3 .

In step 31 , according to the preset correspondence between the voltage and the SOC, the target charging SOC corresponding to the charging voltage at the target charging moment is determined.

Wherein, the target charging moment is one of the charging moments in the target current steady stage.

In step 32, the target charged electric quantity corresponding to the target charging moment is determined.

The method of determining the charged electric quantity corresponding to a certain charging moment has been given in the description of step 21. Referring to the above method, the target charged electric quantity corresponding to the target charging moment can be determined.

In step 33, the capacity of the power battery is determined according to the initial SOC, the target charging SOC and the target charged power of the power battery in the historical charging process.

In a possible implementation manner, the capacity of the power battery may be determined by using a least square method with a forgetting factor. In this embodiment, step 33 can determine the capacity of the power battery in the following manner:

Calculate the i-th iteration through the following formula to obtain the battery capacity Ah_cell(i) corresponding to the i-th iteration:

Ah_cell(i)=Ah_cell(i-1)+k(i)*ε(i)

Among them, Ah_cell(i-1) is the battery capacity calculated in the i-1th time, k(i) is the gain coefficient corresponding to the i-th iteration, ε(i) is the estimation error corresponding to the i-th iteration, and i is A positive integer greater than or equal to 1.

When i reaches the preset number of times, or when the battery capacity corresponding to the i-th iteration converges, the battery capacity corresponding to the i-th iteration is determined as the capacity of the power battery.

For example, the gain coefficient k(i) can be determined by the following formula:

Among them, P(i-1) is the iterative calculation coefficient corresponding to the target charging time, and λ is the forgetting factor. Initially, the iterative calculation coefficient P can be an identity matrix.

Exemplarily, the estimation error ε(i) can be determined by the following formula:

ε(i)=Ah(i)-Ah_cell(i-1)*x(i)

Among them, Ah(i) is the target charged power.

Also, x(i) used in calculating k(i) and ε(i) can be determined by the following formula:

x(i)=SOC(i)-SOC(a)

Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC.

Through the above technical solution, the charging current corresponding to each charging moment of the power battery in the historical charging process is obtained; according to the charging current corresponding to each charging moment, the current steady stage in the historical charging process is determined, wherein, in each current steady stage The corresponding During the charging period, the change value of the charging current does not exceed the preset current change threshold; the target current steady stage is determined from the current steady stage; according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage, the power battery is determined capacity. In this way, the data can be screened, the stage in which the data changes steadily, and the data in this stage can be used to determine the capacity of the power battery, so that even in low-frequency acquisition scenarios, the capacity of the power battery can be determined more accurately .

Fig. 4 is a block diagram of a device for determining the capacity of a power battery according to an embodiment of the present disclosure. As shown in Figure 4, the device 40 may include:

An acquisition module 41, configured to acquire the charging current corresponding to each charging moment of the power battery in the historical charging process;

The first determination module 42 is used to determine the current steady stage in the historical charging process according to the charging current corresponding to each charging moment, wherein, in the charging period corresponding to each of the current steady stages, the change value of the charging current does not exceed Preset current change threshold;

The second determining module 43 is configured to determine a target current steady stage from the current steady stage;

The third determination module 44 is configured to determine the capacity of the power battery according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage.

Optionally, the second determining module 43 includes:

The first determining sub-module is used to determine the charged electric quantity corresponding to each current steady stage according to the charging current corresponding to each charging moment in each current steady stage;

The second determination sub-module is configured to use the current steady stage corresponding to the charged electric quantity with the largest electric quantity as the target current steady stage.

Optionally, the first determining submodule is used to determine the charged electric quantity corresponding to the steady state of the current in the following manner:

Among them, Ah(k) is the charged electricity at the kth charging moment of the current steady stage, t(k) is the initial charging moment of the current steady stage, and t(k+1) is the current steady state The charging time at the end of the stage, I(k) is the charging current at the time t(k).

Optionally, the third determining module 44 includes:

The third determination sub-module is used to determine the target charging SOC corresponding to the charging voltage at the target charging time according to the preset correspondence between the voltage and the SOC, wherein the target charging time is the charging in the target current steady stage one of the moments;

The fourth determining submodule is used to determine the target charged electric quantity corresponding to the target charging moment;

The fifth determination sub-module is used to determine the capacity of the power battery according to the initial SOC of the power battery in the historical charging process, the target charging SOC and the target charged power.

Optionally, the fifth determining submodule is used to determine the capacity of the power battery in the following manner:

Calculate the i-th iteration through the following formula to obtain the battery capacity Ah_cell(i) corresponding to the i-th iteration:

Ah_cell(i)=Ah_cell(i-1)+k(i)*ε(i)

Among them, Ah_cell(i-1) is the battery capacity calculated in the i-1th time, k(i) is the gain coefficient corresponding to the i-th iteration, and ε(i) is the estimation error corresponding to the i-th iteration;

When i reaches the preset number of times, or when the battery capacity corresponding to the i-th iteration converges, the battery capacity corresponding to the i-th iteration is determined as the capacity of the power battery.

Optionally, the gain coefficient k(i) is determined by the following formula:

Among them, P(i-1) is the iterative calculation coefficient corresponding to the target charging time, λ is the forgetting factor, and x(i) is determined by the following formula:

x(i)=SOC(i)-SOC(a)

Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC.

Optionally, the estimation error ε(i) is determined by the following formula:

ε(i)=Ah(i)-Ah_cell(i-1)*x(i)

Among them, Ah(i) is the charged power of the target, and x(i) is determined by the following formula:

x(i)=SOC(i)-SOC(a)

Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC.

Regarding the apparatus in the foregoing embodiments, the specific manner in which each module executes operations has been described in detail in the embodiments related to the method, and will not be described in detail here.

The present disclosure also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the method for determining the capacity of a power battery described in any embodiment of the present disclosure are implemented.

The present disclosure also provides an electronic device, comprising:

a memory on which a computer program is stored;

A processor, configured to execute the computer program in the memory, so as to implement the steps of the method for determining the capacity of a power battery in any embodiment of the present disclosure.

The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure. These simple modifications all belong to the protection scope of the present disclosure.

In addition, it should be noted that the various specific technical features described in the above specific implementation manners may be combined in any suitable manner if there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not further described in this disclosure.

In addition, various implementations of the present disclosure can be combined arbitrarily, as long as they do not violate the idea of the present disclosure, they should also be regarded as the content disclosed in the present disclosure.

Claims (9)

1. A method for determining the capacity of a power battery, characterized in that the method comprises: Obtain the charging current corresponding to each charging moment of the power battery in the historical charging process; According to the charging current corresponding to each charging moment, determine the current steady stage in the historical charging process, wherein, in the charging period corresponding to each said current steady stage, the change value of the charging current does not exceed a preset current change threshold; determining a target current steady stage from the current steady stage; Determine the capacity of the power battery according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage; The determining the target current steady stage from the current steady stage includes: According to the charging current corresponding to each charging moment in each current steady stage, determine the charged electric quantity corresponding to each current steady stage; The current steady stage corresponding to the charged electric quantity with the largest electric quantity value is taken as the target current steady stage. 2. The method according to claim 1, characterized in that the charged electric quantity corresponding to the current steady stage is determined by the following method:

Among them, Ah(k) is the charged electricity at the kth charging moment of the current steady stage, t(k) is the initial charging moment of the current steady stage, and t(k+1) is the current steady state The charging time at the end of the stage, I(k) is the charging current at the time t(k). 3. The method according to claim 1, wherein the determining the capacity of the power battery according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage comprises: Determine the target charging SOC corresponding to the charging voltage at the target charging time according to the preset correspondence between the voltage and the SOC, wherein the target charging time is one of the charging times in the target current steady stage; Determine the target charged electricity corresponding to the target charging moment; The capacity of the power battery is determined according to the initial SOC of the power battery in the historical charging process, the target charging SOC and the target charged power. 4. The method according to claim 3, wherein the capacity of the power battery is determined in the following manner: Calculate the i-th iteration through the following formula to obtain the battery capacity Ah_cell(i) corresponding to the i-th iteration: Ah_cell(i)=Ah_cell(i-1)+k(i)*ε(i) Among them, Ah_cell(i-1) is the battery capacity calculated in the i-1th time, k(i) is the gain coefficient corresponding to the i-th iteration, and ε(i) is the estimation error corresponding to the i-th iteration; When i reaches the preset number of times, or when the battery capacity corresponding to the i-th iteration converges, the battery capacity corresponding to the i-th iteration is determined as the capacity of the power battery. 5. method according to claim 4, is characterized in that, described gain coefficient k (i) is determined by following formula:

Among them, P(i-1) is the iterative calculation coefficient corresponding to the target charging time, λ is the forgetting factor, and x(i) is determined by the following formula: x(i)=SOC(i)-SOC(a) Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC. 6. The method according to claim 4, wherein the estimation error ε(i) is determined by the following formula: ε(i)=Ah(i)-Ah_cell(i-1)*x(i) Among them, Ah(i) is the charged power of the target, and x(i) is determined by the following formula: x(i)=SOC(i)-SOC(a) Wherein, SOC(i) is the target charging SOC, and SOC(a) is the initial SOC. 7. A device for determining the capacity of a power battery, characterized in that the device comprises: An acquisition module, configured to acquire the charging current corresponding to each charging moment of the power battery during the historical charging process; The first determination module is used to determine the current steady stage in the historical charging process according to the charging current corresponding to each charging moment, wherein, in the charging period corresponding to each of the current steady stages, the change value of the charging current does not exceed the preset The set current change threshold; The second determining module is used to determine the target current steady stage from the current steady stage; The third determining module is used to determine the capacity of the power battery according to the charging current and charging voltage corresponding to each charging moment in the target current steady stage; The second determination module includes: The first determining sub-module is used to determine the charged electric quantity corresponding to each current steady stage according to the charging current corresponding to each charging moment in each current steady stage; The second determination sub-module is configured to use the current steady stage corresponding to the charged electric quantity with the largest electric quantity as the target current steady stage. 8. A computer-readable storage medium, on which a computer program is stored, wherein, when the program is executed by a processor, the steps of the method according to any one of claims 1-6 are implemented. 9. An electronic device, characterized in that it comprises: a memory on which a computer program is stored; A processor, configured to execute the computer program in the memory, so as to implement the steps of the method according to any one of claims 1-6.

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