CN118091460A

CN118091460A - SOH estimation method and device for power battery

Info

Publication number: CN118091460A
Application number: CN202211490511.7A
Authority: CN
Inventors: 谢雨; 张信珍; 刘涑凡; 罗勇; 梁伟铭
Original assignee: SAIC Motor Corp Ltd
Current assignee: SAIC Motor Corp Ltd
Priority date: 2022-11-25
Filing date: 2022-11-25
Publication date: 2024-05-28

Abstract

The application provides a power battery SOH estimation method and a device, which relate to the field of automobile power battery monitoring, and the method comprises the following steps: acquiring a pre-established corresponding relation between a power battery health state SOH interval and a temperature interval and an SOH normalized attenuation value, and taking the acquired corresponding relation as a target corresponding relation; acquiring an SOH value of a target battery on a real vehicle at the last moment, and an average temperature and a stage duration of the target battery in a target stage, wherein the acquired average temperature and the acquired stage duration are respectively used as the target temperature and the target duration; and determining the SOH estimated value of the target battery at the current moment according to the target corresponding relation, the SOH value at the last moment, the target temperature and the target duration. In the application, the corresponding relation between the SOH interval and the SOH normalized attenuation value of the power battery in the state of health and the temperature interval is obtained based on the historical charge and discharge data of the power battery on the real vehicle, so that the accuracy of SOH estimation based on the corresponding relation is higher.

Description

SOH estimation method and device for power battery

Technical Field

The application relates to the field of automobile power battery monitoring, in particular to a power battery SOH estimation method and device.

Background

The state of health (Section Of Health, SOH) of the power battery can be used for evaluating the aging degree of the power battery, and the real-time accurate evaluation of SOH has important theoretical significance and application value for improving the use safety of the battery, the service life of the battery, the performance of an electric automobile and the like.

At present, the SOH estimation method of the power battery is to carry out a cyclic charge and discharge test on the power battery in a laboratory environment to obtain aging data of the power battery, then construct an SOH estimation model based on the obtained aging data, and substitute the constructed SOH estimation model into data acquired by a real vehicle to estimate the SOH of the power battery on the real vehicle.

However, the SOH estimation model used by the power battery SOH estimation method is constructed based on ageing data in a laboratory, and cannot simulate the real automobile running environment, so that a large error is generated when the SOH of the real automobile power battery is estimated, and the estimation accuracy of the SOH is low.

Disclosure of Invention

In view of the above, the application provides a method and a device for estimating SOH of a power battery, which are used for solving the problem of low accuracy of SOH estimation in the prior art, and the technical scheme is as follows:

a power cell SOH estimation method comprising:

Acquiring a pre-established corresponding relation between a power battery health state SOH section, a temperature section and an SOH normalized attenuation value, and taking the acquired corresponding relation as a target corresponding relation, wherein the target corresponding relation is obtained based on historical charge and discharge data respectively corresponding to a plurality of target types of power batteries on a real vehicle in a plurality of continuous historical charge and discharge stages, and the SOH normalized attenuation value is used for reflecting the attenuation degree of the SOH value of the power battery in the corresponding SOH section and the corresponding temperature section under the unit working time length; acquiring an SOH value of a target battery on a real vehicle at the last moment, and taking the acquired average temperature and the acquired phase duration of the target battery in a target phase as the target temperature and the target duration respectively, wherein the target battery is a power battery of a target type for which the SOH value needs to be estimated in real time, the last moment is the moment when the target phase is completed, and the target phase is the latest charging phase or discharging phase before the current moment;

And determining the SOH estimated value of the target battery at the current moment according to the target corresponding relation, the SOH value at the last moment, the target temperature and the target duration.

Optionally, the target correspondence includes a first correspondence in a charging phase and a second correspondence in a discharging phase;

The plurality of historical charge and discharge phases comprise a plurality of historical charge phases and a plurality of historical discharge phases, and the historical charge and discharge data respectively corresponding to the plurality of historical charge and discharge phases comprises historical charge data respectively corresponding to the plurality of historical charge phases and historical discharge data respectively corresponding to the plurality of historical discharge phases;

the process for acquiring the first corresponding relation comprises the following steps:

acquiring historical charging data corresponding to a plurality of historical charging stages and historical discharging data corresponding to a plurality of historical discharging stages respectively, and acquiring the factory rated capacity of a brand new power battery of a target type;

according to the historical charging data respectively corresponding to the plurality of historical charging stages, the historical discharging data respectively corresponding to the plurality of historical discharging stages and the factory rated capacity, determining historical SOH values respectively corresponding to the plurality of historical charging stages and the plurality of discharging stages;

For each of a plurality of historical charging stages, determining an SOH normalized attenuation value, a temperature interval and an SOH interval corresponding to the historical charging stage according to a historical SOH value corresponding to the historical charging stage, a historical SOH value corresponding to a backward adjacent historical discharging stage of the historical charging stage and historical charging data corresponding to the historical charging stage;

and determining a first corresponding relation according to the SOH normalized attenuation value, the temperature interval and the SOH interval which are respectively corresponding to the plurality of historical charging stages.

Optionally, obtaining the factory rated capacity of the brand new power battery of the target type includes:

obtaining the discharge time length and the discharge current of the brand-new power battery of the target type under a plurality of experimental conditions, wherein the experimental conditions are that the brand-new power battery is charged to a charge cut-off voltage according to the current of a set charging rate after being kept stand for a set time length at a set temperature, is charged to a current smaller than a preset value at a constant voltage, and is discharged to the discharge cut-off voltage according to the current of the set charging rate after being kept stand for the set time length;

calculating rated capacity under multiple experimental conditions according to the discharge time length and the discharge current under the multiple experimental conditions;

calculating the average value of rated capacity under multiple experimental conditions, and taking the average value as the factory rated capacity of the brand-new power battery of the target type, wherein the deviation between the rated capacity and the average value under each experimental condition is smaller than a preset deviation threshold value.

Optionally, determining the historical SOH values corresponding to the plurality of historical charging phases and the plurality of discharging phases according to the historical charging data corresponding to the plurality of historical charging phases, the historical discharging data corresponding to the plurality of historical discharging phases, and the factory rated capacity, includes:

For each of a plurality of historical charging stages, determining a battery capacity corresponding to the historical charging stage according to a historical charging duration, a historical charging current and a first state of charge (SOC) change value contained in historical charging data corresponding to the historical charging stage, and determining a historical SOH value corresponding to the historical charging stage according to the battery capacity corresponding to the historical charging stage and a factory rated capacity;

for each of the plurality of historical discharge phases, determining a battery capacity corresponding to the historical discharge phase according to a historical discharge duration, a historical discharge current and a second SOC variation value contained in historical discharge data corresponding to the historical discharge phase, and determining a historical SOH value corresponding to the historical discharge phase according to the battery capacity corresponding to the historical discharge phase and a factory rated capacity.

Optionally, determining the SOH normalized attenuation value, the temperature interval, and the SOH interval corresponding to the historical charging stage according to the historical SOH value corresponding to the historical charging stage, the historical SOH value corresponding to the historical charging stage and the historical charging data corresponding to the historical charging stage, where the determining includes:

calculating a historical SOH value corresponding to the historical charging stage, and a first difference value of the historical SOH value corresponding to a backward adjacent historical discharging stage of the historical charging stage;

Calculating a first quotient of the first difference and the charging time length contained in the historical charging data corresponding to the historical charging stage, and taking the first quotient as an SOH normalized attenuation value corresponding to the historical charging stage;

determining a temperature interval in which an average charging temperature contained in the historical charging data corresponding to the historical charging stage is located as a temperature interval corresponding to the historical charging stage;

and determining the SOH section corresponding to the historical charge stage as the SOH section corresponding to the historical charge stage.

Optionally, the process of acquiring the second correspondence includes:

For each of a plurality of history discharge phases, determining an SOH normalized attenuation value, a temperature interval and an SOH interval corresponding to the history discharge phase according to a history SOH value corresponding to the history discharge phase, a history SOH value corresponding to a history charge phase adjacent to the history discharge phase in the backward direction, and history discharge data corresponding to the history discharge phase;

and determining a second corresponding relation according to the SOH normalized attenuation value, the temperature interval and the SOH interval which are respectively corresponding to the historical discharge stages.

Optionally, determining the SOH normalized attenuation value, the temperature interval, and the SOH interval corresponding to the historical discharge stage according to the historical SOH value corresponding to the historical discharge stage, the historical SOH value corresponding to the historical discharge stage and the historical discharge data corresponding to the historical discharge stage, where the determining includes:

Calculating a historical SOH value corresponding to the historical discharge stage, and a second difference value of the historical SOH value corresponding to a historical charge stage adjacent to the historical discharge stage in the backward direction;

Calculating a second quotient of the second difference and the discharge duration contained in the historical discharge data corresponding to the historical discharge stage, and taking the second quotient as an SOH normalized attenuation value corresponding to the historical discharge stage;

Determining a temperature interval in which an average discharge temperature contained in the history discharge data corresponding to the history discharge stage is located as a temperature interval corresponding to the history discharge stage;

And determining the SOH section corresponding to the history discharge stage as the SOH section corresponding to the history discharge stage.

Optionally, determining the SOH estimation value of the target battery at the current time according to the target correspondence, the SOH value of the last time, the target temperature and the target duration includes:

Determining a corresponding relation under a target stage from the target corresponding relations, wherein the determined corresponding relation is a first corresponding relation if the target stage is a charging stage, and is a second corresponding relation if the target stage is a discharging stage;

According to the SOH value and the target temperature at the last moment, searching a corresponding SOH normalized attenuation value from the corresponding relation in the target stage, and taking the searched SOH normalized attenuation value as a target SOH normalized attenuation value;

determining a target SOH attenuation value according to the target SOH normalized attenuation value and the target duration;

And subtracting the SOH value at the previous moment from the target SOH attenuation value, wherein the difference value is used as the SOH estimated value of the target battery at the current moment.

Optionally, the method further comprises:

Acquiring charging data of a target battery in a target time period, wherein the target time period refers to a time period in which the current whole charging stage is located if the current time is a charging stage time, and the target time period refers to a time period in which the last charging stage before the current time is located if the current time is a discharging stage time;

According to the charging data of the target battery in the target time period and the factory rated capacity, calculating the SOH true value of the target battery at the current moment;

Calculating a difference between the SOH true value and the SOH estimated value;

And judging whether the absolute value of the difference is larger than a preset difference threshold value, if so, updating the corresponding relation based on the SOH true value and the charging data of the target battery in the target time period.

A power cell SOH estimation apparatus comprising:

The corresponding relation acquisition module is used for acquiring a corresponding relation between a pre-established power battery health state SOH section, a temperature section and an SOH normalized attenuation value, and taking the acquired corresponding relation as a target corresponding relation, wherein the target corresponding relation is obtained based on historical charge and discharge data respectively corresponding to a plurality of target types of power batteries on a real vehicle in a plurality of continuous historical charge and discharge stages, and the SOH normalized attenuation value is used for reflecting the attenuation degree of the SOH value under the unit working time length of the power batteries in the corresponding SOH section and the corresponding temperature section;

The target data acquisition module is used for acquiring an SOH value of a target battery on the real vehicle at the last moment and an average temperature and a stage duration of the target battery in a target stage, and taking the acquired average temperature and the acquired stage duration as the target temperature and the target duration respectively, wherein the target battery is a power battery of a target type which needs to be subjected to real-time estimation of the SOH value, the last moment is the moment when the target stage is completed, and the target stage is the last charging stage or discharging stage before the current moment;

And the SOH estimation module is used for determining the SOH estimation value of the target battery at the current moment according to the target corresponding relation, the SOH value of the last moment, the target temperature and the target duration.

According to the technical scheme, the SOH estimation method of the power battery provided by the application comprises the steps of firstly obtaining the pre-established corresponding relation between the SOH section of the power battery in the state of health, the temperature section and the SOH normalized attenuation value, taking the obtained corresponding relation as a target corresponding relation, then obtaining the SOH value of the target battery on the real vehicle at the last moment, and the average temperature and the stage duration of the target battery in the target stage, taking the obtained average temperature and the obtained stage duration as the target temperature and the target duration respectively, and then determining the SOH estimation value of the target battery at the current moment according to the target corresponding relation, the SOH value at the last moment, the target temperature and the target duration. In the application, the corresponding relation between the SOH interval and the SOH normalized attenuation value of the power battery in the state of health and the temperature interval is obtained based on the historical charge and discharge data of the power battery on the real vehicle, so that the accuracy of SOH estimation based on the corresponding relation is higher.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic flow chart of a SOH estimation method for a power battery according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a target type power cell during each successive charge and discharge phase of the power cell during historical use;

fig. 3 is a schematic structural diagram of an SOH estimation device for a power battery according to an embodiment of the present application;

fig. 4 is a block diagram of a hardware structure of a SOH estimation device for a power battery according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

In view of the problems of the prior art, the present inventors have conducted intensive studies and finally have proposed a power battery SOH estimation method, which is described in the following examples.

Referring to fig. 1, a flowchart of a power battery SOH estimation method according to an embodiment of the present application is shown, where the power battery SOH estimation method may include:

step S101, acquiring a pre-established corresponding relation between a power battery health state SOH section, a temperature section and an SOH normalized attenuation value, and taking the acquired corresponding relation as a target corresponding relation.

Specifically, the embodiment of the application can pre-establish the corresponding relation between the SOH interval, the temperature interval and the SOH normalized attenuation value of the power battery in the health state based on the historical charge and discharge data respectively corresponding to a plurality of target types of power batteries on the real vehicle in a plurality of continuous historical charge and discharge stages. Here, the SOH normalized attenuation value is used to reflect the degree of attenuation of the SOH value at the unit operation time of the power battery in the corresponding SOH section and the corresponding temperature section.

It should be noted that, the target correspondence in this step is obtained based on the historical charge and discharge data of the power battery of the target type, so that the target correspondence can only be used for estimating the SOH value of the power battery of the target type.

Optionally, the historical charge-discharge data includes charge-discharge data corresponding to each of a plurality of charge-discharge phases of a power battery of a target type, which is used from factory installation to actual vehicle, i.e., the plurality of historical charge-discharge phases include a plurality of historical charge phases and a plurality of historical discharge phases, and correspondingly, the historical charge-discharge data corresponding to each of the plurality of historical charge-discharge phases includes historical charge data corresponding to each of the plurality of historical charge phases and historical discharge data corresponding to each of the plurality of historical discharge phases.

Taking any one of the plurality of target types of power cells as an example, referring to fig. 2, the present embodiment defines each successive charge and discharge phase during the history of use as: in the case of the power battery, the history charge/discharge data includes the history charge data corresponding to each history charge stage such as the history charge stage 1 and the history discharge stage 2 and the history charge data corresponding to each history charge stage such as the history charge stage 1 and the history charge stage 2.

Step S102, acquiring an SOH value of a target battery on the real vehicle at the last moment, and an average temperature and a stage duration of the target battery in a target stage, wherein the acquired average temperature and the acquired stage duration are respectively used as the target temperature and the target duration.

The target battery is a power battery of a target type, which needs to perform real-time estimation of an SOH value, and the last time is the time when the target phase is completed, and the target phase is the last charging phase or discharging phase before the current time.

Alternatively, the SOH value obtained at the last time in this step may be the SOH estimated value estimated by the present application (in which the initial SOH value is set to 1), or the SOH actual value calculated at the last time (compared with the method for obtaining the SOH estimated value of the present application, the method for obtaining the SOH actual value is large in calculation amount, takes time, and is poor in real time).

In this step, the average temperature refers to an average value of real-time temperatures when the target battery is in the target phase, and the phase duration refers to a total duration that the target battery is in the target phase.

For convenience of the following description and distinction, the average temperature obtained in this step is defined as a target temperature, and the period of time obtained in this step is defined as a target period of time.

Step S103, determining an SOH estimated value of the target battery at the current moment according to the target corresponding relation, the SOH value of the last moment, the target temperature and the target duration.

Specifically, the SOH value of the target battery at the current moment can be estimated in real time by the step, and the SOH estimated value at the current moment is obtained.

According to the power battery SOH estimation method provided by the application, firstly, the corresponding relation between the pre-established power battery state SOH section, the temperature section and the SOH normalized attenuation value is obtained, the obtained corresponding relation is used as a target corresponding relation, then, the SOH value of the target battery on the real vehicle at the last moment, the average temperature and the stage duration of the target battery at the target stage are obtained, the obtained average temperature and the obtained stage duration are respectively used as the target temperature and the target duration, and then, the SOH estimation value of the target battery at the current moment is determined according to the target corresponding relation, the SOH value at the last moment, the target temperature and the target duration. In the application, the corresponding relation between the SOH interval and the SOH normalized attenuation value of the power battery in the state of health and the temperature interval is obtained based on the historical charge and discharge data of the power battery on the real vehicle, so that the accuracy of SOH estimation based on the corresponding relation is higher.

In one embodiment of the present application, the process of "step S101, obtaining the correspondence between the SOH interval and the SOH normalized attenuation value of the power battery in the pre-established target type" is described.

Optionally, the target correspondence includes a first correspondence in a charging phase and a second correspondence in a discharging phase. In this embodiment, a first correspondence relationship between the SOH interval and the SOH normalized attenuation value of the power battery in the charging phase and a second correspondence relationship between the SOH interval and the temperature interval and the SOH normalized attenuation value of the power battery in the discharging phase may be established based on the historical charge-discharge data respectively corresponding to the plurality of historical charge-discharge phases mentioned in the foregoing embodiment.

As described in the foregoing step S101, the plurality of history charge-discharge phases include a plurality of history charge-discharge phases and a plurality of history discharge phases, and the history charge-discharge data respectively corresponding to the plurality of history charge-discharge phases includes history charge-discharge data respectively corresponding to the plurality of history charge-discharge phases and history discharge data respectively corresponding to the plurality of history discharge phases.

On this basis, a process of acquiring the first correspondence and the second correspondence is described.

Optionally, the process of acquiring the first correspondence includes:

And A1, acquiring historical charging data corresponding to a plurality of historical charging stages and historical discharging data corresponding to a plurality of historical discharging stages respectively, and acquiring the factory rated capacity of a brand-new power battery of a target type.

In an optional embodiment, the step may obtain, through screening, historical charge and discharge data corresponding to each of the plurality of historical charge phases from the big data platform. Optionally, the historical charging data corresponding to any one of the historical charging phases obtained in the step includes one or more of the following data: historical charging duration, historical charging current, first State Of Charge (SOC) variation value and average charging temperature; optionally, the historical discharge data corresponding to any one of the historical discharge phases obtained in the step includes one or more of the following data: historical discharge duration, historical discharge current, second SOC variation value, and average discharge temperature.

The data included in the history charge/discharge data is merely an example, and is not intended to limit the present application.

The step can also obtain the factory rated capacity of the brand-new power battery of the target type, wherein the factory rated capacity refers to the rated capacity of the brand-new power battery of the target type when the brand-new power battery is shipped.

In an optional embodiment, the factory rated capacity obtained in this step refers to a factory rated capacity at a set charging rate and a set temperature, and optionally, the process of obtaining the factory rated capacity at the set charging rate and the set temperature includes:

and step A11, acquiring the discharge duration and the discharge current of the brand-new power battery of the target type under the condition of multiple experiments.

The experimental conditions are that after the brand new power battery is kept stand for a set period of time at a set temperature, the brand new power battery is charged to a charge cut-off voltage according to a current with a set charge rate, and is charged at a constant voltage until the current is smaller than a preset value, and then the brand new power battery is discharged to a discharge cut-off voltage according to the current with the set charge rate after the brand new power battery is kept stand for the set period of time. Here, the purpose of letting the power battery stand is to stabilize the voltage of the power battery.

Optionally, the temperature is set to 25 ℃, the charging rate is set to 1C, the set time length is 1 hour, and the preset value is set to 0.05C.

It should be noted that, the step of obtaining the discharge duration and the discharge current under the multiple experimental conditions is to obtain a relatively accurate factory rated capacity, so the "multiple" is at least 3 times.

And step A12, calculating rated capacity under multiple experimental conditions according to the discharge time length and the discharge current under the multiple experimental conditions.

Specifically, the rated capacity (Ah) =discharge current (a) ×discharge duration (h), and in this step, the discharge duration and the discharge current under each experimental condition may be substituted into the calculation formula to obtain the rated capacity under each experimental condition.

And A13, calculating an average value of rated capacities under the condition of multiple experiments, and taking the average value as the factory rated capacity of the brand-new power battery of the target type.

Alternatively, in order to ensure that the factory rated capacity obtained in this embodiment is more accurate, when the deviation between the rated capacity and the average value under each experimental condition is smaller than a preset deviation threshold (for example, 2%), the average value may be taken as the factory rated capacity of the brand-new power battery of the target type.

Optionally, after the factory rated capacity is calculated, the factory rated capacity can be uploaded to a big data platform for storage.

And A2, determining historical SOH values corresponding to the plurality of historical charging stages and the plurality of discharging stages according to the historical charging data corresponding to the plurality of historical charging stages, the historical discharging data corresponding to the plurality of historical discharging stages and the factory rated capacity.

Optionally, the process of this step includes the following steps a21 and a22:

And A21, for each of a plurality of historical charging stages, determining the battery capacity corresponding to the historical charging stage according to the historical charging duration, the historical charging current and the first state of charge (SOC) change value contained in the historical charging data corresponding to the historical charging stage, and determining the historical SOH value corresponding to the historical charging stage according to the battery capacity corresponding to the historical charging stage and the factory rated capacity.

In one possible implementation manner, the determining the battery capacity corresponding to the historical charging stage according to the historical charging duration, the historical charging current and the first SOC variation value contained in the historical charging data corresponding to the historical charging stage in this step may include: according to the historical charging duration and the historical charging current contained in the historical charging data corresponding to the historical charging stage, determining the battery charging quantity corresponding to the historical charging stage, calculating the quotient of the battery charging quantity corresponding to the historical charging stage and the first SOC variation value, and taking the calculated quotient as the battery capacity corresponding to the historical charging stage.

Specifically, it should be understood by those skilled in the art that each charging phase of the power battery is substantially composed of a plurality of sub-charging phases, and the charging current and the charging duration of each sub-charging phase are different, and then this step may use equation E ₁＝∑i_jt_j to calculate the battery charge corresponding to the historical charging phase, where E ₁ represents the battery charge corresponding to the historical charging phase, j represents the j sub-charging phase included in the historical charging phase, i _j represents the historical charging current of the j sub-charging phase, and t _j represents the historical charging duration of the j sub-charging phase.

After determining the battery charge level E ₁ corresponding to the historical charging stage, the battery capacity corresponding to the historical charging stage may be calculated by using the formula Q _t1＝E₁/SOC₁, where Q _t1 represents the battery capacity corresponding to the historical charging stage and SOC ₁ represents the first SOC variation value.

In another possible implementation manner, the determining the historical SOH value corresponding to the historical charging stage according to the battery capacity and the factory rated capacity corresponding to the historical charging stage in this step may include: equivalent battery capacity corresponding to the historical charging stage is equivalent to the set charging multiplying power and the set temperature, and equivalent capacity corresponding to the historical charging stage is obtained; calculating the ratio of the equivalent capacity corresponding to the historical charging stage to the factory rated capacity, and taking the calculated ratio as the historical SOH value corresponding to the historical charging stage.

Specifically, since the factory rated capacity obtained in the foregoing step is the factory rated capacity at the set charge rate and the set temperature, in order to be able to be consistent when calculating the historical SOH value, the calculated battery capacity needs to be equivalent to the set charge rate and the set temperature in this step to obtain the equivalent capacity corresponding to the historical charge stage.

Optionally, in this step, the following formula (1) is first adopted to make the battery capacity corresponding to the historical charging stage equivalent to the set temperature, so as to obtain the first equivalent capacity corresponding to the historical charging stage.

Where Q _t2 represents a first equivalent capacity corresponding to the historical charging stage, K represents a temperature coefficient (constant), tp ₁ represents an average charging temperature included in the historical charging data corresponding to the historical charging stage, and tp ₂ represents a set temperature.

Optionally, the step may be to equivalent the first equivalent capacity corresponding to the historical charging stage to the set charging rate based on the equivalent coefficient in the following table 1, so as to obtain the second equivalent capacity corresponding to the historical charging stage, where the second equivalent capacity is "equivalent capacity corresponding to the historical charging stage" in this embodiment.

Table 1 equivalent coefficients of battery capacity at different charge rates

Charging rate	0.5C	1C	2C	Other specific multiplying power
					Rated capacity of delivery	x₁Ah	x₂Ah	x₃Ah	x_eAh
Equivalent coefficient	x₂/x₁	1	x₂/x₃	x₂/x_e

X ₁、x₂、x₃ and x _e in the table are preset values.

After the equivalent capacity corresponding to the historical charging stage is obtained, dividing the equivalent capacity corresponding to the historical charging stage by the factory rated capacity to obtain the historical SOH value corresponding to the historical charging stage.

And step A22, for each of a plurality of historical discharge stages, determining the battery capacity corresponding to the historical discharge stage according to the historical discharge duration, the historical discharge current and the second SOC variation value contained in the historical discharge data corresponding to the historical discharge stage, and determining the historical SOH value corresponding to the historical discharge stage according to the battery capacity corresponding to the historical discharge stage and the factory rated capacity.

In one possible implementation manner, the determining the battery capacity corresponding to the historical discharge stage according to the historical discharge duration, the historical discharge current and the second SOC variation value contained in the historical discharge data corresponding to the historical discharge stage in this step may include: according to the historical discharge time length and the historical discharge current contained in the historical discharge data corresponding to the historical discharge stage, determining the battery discharge electric quantity corresponding to the historical discharge stage, calculating the quotient of the battery discharge electric quantity corresponding to the historical discharge stage and the second SOC variation value, and taking the calculated quotient as the battery capacity corresponding to the historical discharge stage.

In another possible implementation manner, the determining the historical SOH value corresponding to the historical discharging stage according to the battery capacity corresponding to the historical discharging stage and the factory rated capacity in this step may include: equivalent battery capacity corresponding to the historical discharge stage is equivalent to the set charging multiplying power and the set temperature, and equivalent capacity corresponding to the historical discharge stage is obtained; calculating the ratio of the equivalent capacity corresponding to the historical discharge stage to the factory rated capacity, and taking the calculated ratio as the historical SOH value corresponding to the historical discharge stage.

The specific implementation process of this step is similar to that of the foregoing step a21, and the detailed description will be referred to the foregoing description, and will not be repeated here. And A3, for each historical charging stage in the plurality of historical charging stages, determining an SOH normalized attenuation value, a temperature interval and an SOH interval corresponding to the historical charging stage according to the historical SOH value corresponding to the historical charging stage, the historical SOH value corresponding to the historical discharging stage adjacent to the historical charging stage in the backward direction and the historical charging data corresponding to the historical charging stage.

The process of the step comprises the following steps A31 to A34:

and step A31, calculating a historical SOH value corresponding to the historical charging stage, and calculating a first difference value of the historical SOH value corresponding to a historical discharging stage adjacent to the historical charging stage in the backward direction.

Here, the history discharge phase adjacent to the history charge phase in the backward direction refers to the last history discharge phase after the history charge phase. Taking the historical charging stage 1 of fig. 2 as an example, the calculation formula of the first difference is: Δsoh _c1＝SOH_c1-SOH_f2, where Δsoh _c1 represents a first difference value corresponding to the history charge phase 1, SOH _c1 represents a history SOH value corresponding to the history charge phase 1, and SOH _f2 represents a history SOH value corresponding to the history discharge phase 2, that is, a history SOH value corresponding to a history discharge phase adjacent to the history charge phase 1 in the backward direction.

And A32, calculating a first quotient of the first difference and the charging time length contained in the historical charging data corresponding to the historical charging stage, and taking the first quotient as an SOH normalized attenuation value corresponding to the historical charging stage.

Specifically, in this step, Δsoh _cstd＝ΔSOH_c/x_c may be used to calculate an SOH normalized attenuation value corresponding to the historical charging stage, where Δsoh _c represents a first difference value corresponding to the historical charging stage, x _c represents a charging duration included in the historical charging data corresponding to the historical charging stage, and Δsoh _cstd represents an SOH normalized attenuation value corresponding to the historical charging stage.

And step A33, determining a temperature interval in which the average charging temperature contained in the historical charging data corresponding to the historical charging stage is located as the temperature interval corresponding to the historical charging stage.

Specifically, the step may preset a plurality of temperature intervals, and the temperature intervals may be, for example, [0,5 ], [5,10 ], [10,20 ], [20,30 ], [30, 35), …, [55, 60), where the units of the values in the intervals are in ℃. Here, the plurality of temperature zones are different in zone size because the SOH values of the power battery are different in the degree of attenuation in the different temperature zones, wherein the degree of attenuation in the SOH values is small in [10, 20) and [20, 30) and the degree of attenuation in the high-temperature or low-temperature zone is large.

The step may determine a temperature interval corresponding to the historical charging stage according to which of a plurality of temperature intervals the average charging temperature included in the historical charging data corresponding to the historical charging stage is in, for example, if the average charging temperature included in the historical charging data corresponding to the historical charging stage is 23 ℃, the temperature interval corresponding to the historical charging stage is [20,30 ].

And step A34, determining the SOH section where the historical SOH value corresponding to the historical charging stage is located as the SOH section corresponding to the historical charging stage.

Specifically, this step may preset a plurality of SOH intervals, which may be, for example, [1,0.95 ], [0.95,0.9 ], [0.9,0.85 ], [0.85,0.8), and [0.8,0.7).

In this step, the SOH section corresponding to the history charging stage may be determined according to which SOH section of the plurality of SOH sections the history SOH value corresponding to the history charging stage is located, for example, if the history SOH value corresponding to the history charging stage is 0.83, the SOH section corresponding to the history charging stage is [0.85,0.8 ].

And A4, determining a first corresponding relation according to SOH normalized attenuation values, temperature intervals and SOH intervals respectively corresponding to the plurality of historical charging stages.

Alternatively, the first correspondence obtained in this step may be in a table form, for example, table 2 below.

TABLE 2 correspondence between SOH intervals, temperature intervals and SOH normalized attenuation values at the charging stage

In the table, Δsoh _cstd11 represents SOH normalized attenuation values corresponding to SOH section [1,0.95) and temperature section [0,5 ] in the charging phase, Δsoh _cstd12 represents SOH normalized attenuation values corresponding to SOH section [0.95,0.9) and temperature section [0, 5) in the charging phase, Δsoh _cstd13 represents SOH normalized attenuation values corresponding to SOH section [0.9,0.85) and temperature section [0, 5) in the charging phase, Δsoh _cstd21 represents SOH normalized attenuation values corresponding to SOH section [1,0.95) and temperature section [5, 10) in the charging phase, Δsoh _cstd22 represents SOH normalized attenuation values corresponding to SOH section [0.95,0.9) and temperature section [5, 10) in the charging phase, Δsoh _cstd23 represents SOH normalized attenuation values corresponding to SOH section [0.9,0.85) and temperature section [5, 10) in the charging phase, Δsoh _cstd31 represents SOH normalized attenuation values corresponding to SOH section [1,0.95) and temperature section [10,20 ] in the charging phase, and SOH normalized attenuation values corresponding to SOH section [ 20 ] in the charging phase, Δsoh _cstd22 represents SOH normalized attenuation values corresponding to SOH section [ 3435) in the charging phase and temperature section [ 20, 20).

Continuing from the description above, the process of obtaining the second correspondence relationship on the basis of A1 and A2 may include:

B1, for each of a plurality of historical discharge phases, determining an SOH normalized attenuation value, a temperature interval and an SOH interval corresponding to the historical discharge phase according to a historical SOH value corresponding to the historical discharge phase, a historical SOH value corresponding to a backward adjacent historical charge phase of the historical discharge phase and historical discharge data corresponding to the historical discharge phase.

The process of the step comprises the following steps B11 to B14:

And step B11, calculating a historical SOH value corresponding to the historical discharge stage, and calculating a second difference value of the historical SOH value corresponding to the historical charge stage which is adjacent to the historical discharge stage in the backward direction.

Here, the history charge phase adjacent to the history discharge phase in the backward direction refers to the last history charge phase after the history discharge phase. Taking the historical discharge stage 1 of fig. 2 as an example, the calculation formula of the first difference is: Δsoh _f1＝SOH_f1-SOH_c1, where Δsoh _f1 represents the second difference value corresponding to the history discharge stage 1, SOH _f1 represents the history SOH value corresponding to the history discharge stage 1, and SOH _c1 represents the history SOH value corresponding to the history charge stage 1, that is, the history SOH value corresponding to the history charge stage adjacent backward to the history discharge stage 1.

And step B12, calculating a second quotient of the second difference and the discharge duration contained in the historical discharge data corresponding to the historical discharge stage, and taking the second quotient as an SOH normalized attenuation value corresponding to the historical discharge stage.

Specifically, in this step, Δsoh _fstd＝ΔSOH_f/x_f may be used to calculate an SOH normalized attenuation value corresponding to the historical charging stage, where Δsoh _f represents a second difference value corresponding to the historical discharging stage, x _f represents a discharge duration included in the historical discharging data corresponding to the historical discharging stage, and Δsoh _fstd represents an SOH normalized attenuation value corresponding to the historical discharging stage.

And step B13, determining a temperature interval in which the average discharge temperature contained in the historical discharge data corresponding to the historical discharge stage is located as a temperature interval corresponding to the historical discharge stage.

It should be noted that, the plurality of temperature intervals preset in this step may be the same as or different from the temperature interval in the step a33, and may be specifically set according to actual situations.

The step may determine a temperature section corresponding to the history discharge stage according to which of a plurality of temperature sections the average discharge temperature included in the history discharge data corresponding to the history discharge stage is located.

And step B14, determining the SOH section where the historical SOH value corresponding to the historical discharge stage is located as the SOH section corresponding to the historical discharge stage.

The SOH intervals preset in this step may be the same as or different from the SOH intervals in step a34, and may be specifically set according to actual situations.

In this step, the SOH section corresponding to the history discharge stage may be determined according to which SOH section among the plurality of SOH sections the history SOH value corresponding to the history discharge stage is located.

And B2, determining a second corresponding relation according to SOH normalized attenuation values, temperature intervals and SOH intervals respectively corresponding to the historical discharge stages.

Alternatively, the second correspondence obtained in this step may be in a table form, for example, table 3 below.

TABLE 3 correspondence between SOH interval, temperature interval and SOH normalized attenuation value at discharge stage

In the table, Δsoh _fstd11 represents SOH normalized attenuation values corresponding to SOH section [1,0.95) and temperature section [0,5 ] in the discharge phase, Δsoh _fstd12 represents SOH normalized attenuation values corresponding to SOH section [0.95,0.9) and temperature section [0, 5) in the discharge phase, Δsoh _fstd13 represents SOH normalized attenuation values corresponding to SOH section [0.9,0.85) and temperature section [0, 5) in the discharge phase, Δsoh _fstd21 represents SOH normalized attenuation values corresponding to SOH section [1,0.95) and temperature section [5,10 ] in the discharge phase, Δsoh _fstd22 represents SOH normalized attenuation values corresponding to SOH section [0.95,0.9) and temperature section [5, 10) in the discharge phase, Δsoh _fstd23 represents SOH normalized attenuation values corresponding to SOH section [0.9,0.85) and temperature section [5, 10) in the discharge phase, Δsoh _fstd31 represents SOH normalized attenuation values corresponding to SOH section [1,0.95) and temperature section [10,20 ] in the discharge phase, and SOH normalized attenuation values corresponding to SOH section [ 20, 20 ] in the discharge phase.

In summary, the application can determine the corresponding relation (i.e. the first corresponding relation) of the SOH section, the temperature section and the SOH normalized attenuation value in the charging stage and the corresponding relation (i.e. the second corresponding relation) of the SOH section, the temperature section and the SOH normalized attenuation value in the discharging stage based on the historical charging data corresponding to the plurality of historical charging stages, and the determined corresponding relation is more matched with the real automobile running environment because the historical charging and discharging data are the data in the real automobile running environment, and the SOH estimated value determined based on the corresponding relation is more accurate.

The following describes the procedure of "step S103, determining the SOH estimation value of the target battery at the current time according to the target correspondence relationship, the SOH value of the previous time, the target temperature and the target time period" described above.

Specifically, the process of determining the SOH estimation value of the target battery at the current time according to the target correspondence, the SOH value of the previous time, the target temperature and the target duration in step S103 may include:

and C1, determining the corresponding relation in the target stage from the target corresponding relation.

And if the target stage is a charging stage, the determined corresponding relation is a first corresponding relation, and if the target stage is a discharging stage, the determined corresponding relation is a second corresponding relation.

And C2, searching a corresponding SOH normalized attenuation value from the corresponding relation in the target stage according to the SOH value and the target temperature at the last moment, and taking the searched SOH normalized attenuation value as a target SOH normalized attenuation value.

For example, if the SOH value at the previous time is 0.87, the target temperature is 11 ℃, and the target phase is the charging phase, the table is checked according to table 2, and the obtained target SOH normalized attenuation value is Δsoh _cstd33.

For another example, if the SOH value at the previous time is 0.96, the target temperature is 8 ℃, and the target phase is the discharge phase, the table is searched according to table 3, and the obtained target SOH normalized attenuation value is Δsoh _fstd21.

And C3, determining a target SOH attenuation value according to the target SOH normalized attenuation value and the target duration.

Specifically, the target SOH attenuation value can be obtained by calculation using the formula (2).

Δsoh' =Δsoh _s'_td S equation (2)

Where ΔSOH _s'_td represents the target SOH normalized attenuation value, S represents the target time period, and ΔSOH' represents the target SOH attenuation value.

Here, the target SOH attenuation value refers to the degree of attenuation of the SOH value at the present time compared to the SOH value at the previous time.

And C4, subtracting the SOH value at the previous moment from the target SOH attenuation value, and taking the difference value as an SOH estimated value of the target battery at the current moment.

Specifically, in this step, the SOH value at the current time may be calculated by using formula (3).

SOH (t+1) =soh (t) - Δsoh' formula (3)

In the expression, SOH (t) represents the SOH value at the previous time, and SOH (t+1) represents the SOH value at the current time.

It should be noted that, the SOH value at the current time calculated in this step is an estimated value based on the SOH estimation method of the power battery provided by the present application, but is not a true value, so this step defines the SOH value at the current time as the SOH estimated value at the current time.

In the embodiment, the SOH value at the current moment is estimated based on the corresponding relation, so that the finally obtained SOH estimated value at the current moment is more accurate. The application can easily determine the SOH estimated value at the current moment based on the corresponding relation, and has simple calculation process and better instantaneity.

In an alternative embodiment, it is considered that as the charge and discharge phases of the power battery are increased, the historical charge and discharge data are increased, and the correspondence obtained in step S101 may need to be updated. For this purpose, the power battery SOH estimation method provided by the application may further include the following steps:

and D1, acquiring charging data of the target battery in a target time period.

If the current time is the charging stage time, the target time period refers to the time period in which the current whole charging stage is located, and if the current time is the discharging stage time, the target time period refers to the time period in which the last charging stage before the current time is located.

And D2, calculating the SOH true value of the target battery at the current moment according to the charging data of the target battery in the target time period and the factory rated capacity.

The calculation process in this step corresponds to the calculation process in the foregoing step a21 or a22, and the detailed description thereof will be referred to in the foregoing description, and will not be repeated here.

And D3, calculating a difference value between the SOH true value and the SOH estimated value.

And D4, judging whether the absolute value of the difference is larger than a preset difference threshold, and if so, updating the corresponding relation based on the SOH true value and the charging data of the target battery in the target time period.

The updating process of this step corresponds to the processes of the foregoing steps A3 to A4, and the detailed description of the foregoing processes will be referred to herein, and will not be repeated.

The embodiment can update the corresponding relationship obtained in the step S101 along with the increase of the charge and discharge times of the power battery of the target type, thereby improving the accuracy of the corresponding relationship.

In one possible implementation manner, the embodiment may construct a first corresponding relationship according to steps A1 to A4, construct a second corresponding relationship according to steps B1 to B2, and then construct an SOH attenuation model based on the first corresponding relationship, the second corresponding relationship, formula (2) and formula (3). And obtaining the SOH estimated value of the target battery at the current moment after inputting the SOH value, the target temperature and the target time length at the last moment based on the constructed SOH attenuation model.

By the SOH attenuation model provided by the embodiment, the SOH value of the battery can be estimated in real time only by using the SOH value of the last moment, the target temperature and the target time length, the calculated amount is small, and the calculation speed is high.

The embodiment of the application further provides a power battery SOH estimation device, the power battery SOH estimation device provided by the embodiment of the application is described below, and the power battery SOH estimation device described below and the power battery SOH estimation method described above can be referred to correspondingly.

Referring to fig. 3, a schematic structural diagram of a power battery SOH estimation device according to an embodiment of the present application is shown, and as shown in fig. 3, the power battery SOH estimation device may include: a correspondence acquisition module 301, a target data acquisition module 302, and an SOH estimation module 303.

The correspondence acquiring module 301 is configured to acquire a correspondence between a pre-established SOH interval and a temperature interval of a power battery and an SOH normalized attenuation value, and take the acquired correspondence as a target correspondence, where the target correspondence is obtained based on historical charge and discharge data of a plurality of target types of power batteries on a real vehicle, where the historical charge and discharge data correspond to each other in a plurality of continuous historical charge and discharge phases, and the SOH normalized attenuation value is used to reflect attenuation degrees of the SOH value under a unit working duration of the power battery in the corresponding SOH interval and the corresponding temperature interval.

The target data obtaining module 302 is configured to obtain an SOH value of a target battery on the real vehicle at a previous time, and an average temperature and a period duration of the target battery in a target period, and take the obtained average temperature and period duration as the target temperature and the target duration, respectively, where the target battery is a power battery of a target type that needs to perform real-time estimation of the SOH value, the previous time is a time when the target period is completed, and the target period is a last charging period or discharging period before the current time.

The SOH estimation module 303 is configured to determine an SOH estimation value of the target battery at the current time according to the target correspondence, the SOH value of the last time, the target temperature and the target duration.

The power battery SOH estimation device provided by the application firstly acquires a pre-established corresponding relation between a power battery health state SOH section and a temperature section and an SOH normalized attenuation value, takes the acquired corresponding relation as a target corresponding relation, then acquires an SOH value of a target battery on a real vehicle at the last moment, and an average temperature and a stage duration of the target battery at a target stage, takes the acquired average temperature and the acquired stage duration as the target temperature and the target duration respectively, and then determines the SOH estimation value of the target battery at the current moment according to the target corresponding relation, the SOH value at the last moment, the target temperature and the target duration. In the application, the corresponding relation between the SOH interval and the SOH normalized attenuation value of the power battery in the state of health and the temperature interval is obtained based on the historical charge and discharge data of the power battery on the real vehicle, so that the accuracy of SOH estimation based on the corresponding relation is higher.

In one possible implementation manner, the target correspondence includes a first correspondence in a charging phase and a second correspondence in a discharging phase.

The plurality of history charge-discharge phases comprise a plurality of history charge-discharge phases and a plurality of history discharge phases, and the history charge-discharge data respectively corresponding to the plurality of history charge-discharge phases comprises history charge-discharge data respectively corresponding to the plurality of history charge-discharge phases and history discharge data respectively corresponding to the plurality of history discharge phases.

Then, the process of the correspondence relation acquisition module 301 acquiring the first correspondence relation may include: the system comprises a historical data acquisition module, a historical SOH value determination module, a first data correspondence module and a first correspondence determination module.

The historical data acquisition module is used for acquiring historical charging data corresponding to a plurality of historical charging phases and historical discharging data corresponding to a plurality of historical discharging phases respectively, and acquiring the factory rated capacity of the brand-new power battery of the target type.

The historical SOH value determining module is used for determining the historical SOH values corresponding to the plurality of historical charging stages and the plurality of discharging stages according to the historical charging data corresponding to the plurality of historical charging stages, the historical discharging data corresponding to the plurality of historical discharging stages and the factory rated capacity.

The first data corresponding module is used for determining an SOH normalized attenuation value, a temperature interval and an SOH interval corresponding to each historical charging stage of the plurality of historical charging stages according to the historical SOH value corresponding to the historical charging stage, the historical SOH value corresponding to the historical discharging stage adjacent to the historical charging stage in the backward direction and the historical charging data corresponding to the historical charging stage.

The first corresponding relation determining module is used for determining a first corresponding relation according to SOH normalized attenuation values, temperature intervals and SOH intervals which correspond to the historical charging stages respectively.

In one possible implementation, the historical data acquisition module may include, when acquiring the factory rated capacity of the brand-new power battery of the target type: the system comprises a discharge data acquisition module, a rated capacity calculation module and a factory rated capacity determination module.

The discharging data acquisition module is used for acquiring the discharging time length and the discharging current of the brand-new power battery of the target type under the multiple experiment condition, wherein the experiment condition is that the brand-new power battery is charged to the charging cut-off voltage according to the current of the set charging multiplying power after being kept still for the set time length at the set temperature, is charged to the current smaller than the preset value at a constant voltage, and is discharged to the discharging cut-off voltage according to the current of the set charging multiplying power after being kept still for the set time length.

And the rated capacity calculation module is used for calculating rated capacity under the multiple experimental conditions according to the discharge duration and the discharge current under the multiple experimental conditions.

The factory rated capacity determining module is used for calculating the average value of rated capacities under multiple experimental conditions and taking the average value as the factory rated capacity of the brand-new power battery of the target type, wherein the deviation between the rated capacity and the average value under each experimental condition is smaller than a preset deviation threshold value.

In one possible implementation manner, the historical SOH value determining module may include: a first historical SOH value calculation module and a second historical SOH value calculation module.

The first historical SOH value calculation module is used for determining, for each of a plurality of historical charging stages, a battery capacity corresponding to the historical charging stage according to a historical charging duration, a historical charging current and a first state of charge (SOC) change value contained in historical charging data corresponding to the historical charging stage, and determining a historical SOH value corresponding to the historical charging stage according to the battery capacity corresponding to the historical charging stage and a factory rated capacity.

The second historical SOH value calculation module is used for determining, for each of a plurality of historical discharge phases, a battery capacity corresponding to the historical discharge phase according to a historical discharge duration, a historical discharge current and a second SOC change value contained in historical discharge data corresponding to the historical discharge phase, and determining a historical SOH value corresponding to the historical discharge phase according to the battery capacity corresponding to the historical discharge phase and a factory rated capacity.

In one possible implementation manner, the first data corresponding module may include: the system comprises a first difference value calculation module, a first quotient calculation module, a first temperature interval corresponding module and a first SOH interval corresponding module.

The first difference calculating module is used for calculating a historical SOH value corresponding to the historical charging stage and a first difference of the historical SOH value corresponding to a historical discharging stage adjacent to the historical charging stage in the backward direction.

The first quotient calculation module is configured to calculate a first quotient of the first difference and a charging duration included in the historical charging data corresponding to the historical charging stage, and use the first quotient as an SOH normalized attenuation value corresponding to the historical charging stage.

The first temperature interval corresponding module is configured to determine a temperature interval in which an average charging temperature included in the historical charging data corresponding to the historical charging stage is located as a temperature interval corresponding to the historical charging stage.

And the first SOH section corresponding module is used for determining the SOH section where the historical SOH value corresponding to the historical charging stage is located as the SOH section corresponding to the historical charging stage.

In one possible implementation manner, the process of acquiring the second correspondence by the correspondence acquiring module 301 may include: the device comprises a second data corresponding module and a second corresponding relation determining module.

The second data corresponding module is configured to determine, for each of the plurality of historical discharge phases, an SOH normalized attenuation value, a temperature interval, and an SOH interval corresponding to the historical discharge phase according to a historical SOH value corresponding to the historical discharge phase, a historical SOH value corresponding to a historical charge phase that is backward adjacent to the historical discharge phase, and historical discharge data corresponding to the historical discharge phase.

And the second corresponding relation determining module is used for determining a second corresponding relation according to the SOH normalized attenuation value, the temperature interval and the SOH interval which are respectively corresponding to the historical discharge stages.

In one possible implementation manner, the second data correspondence module may include: the system comprises a second difference value calculation module, a second quotient calculation module, a second temperature interval corresponding module and a second SOH interval corresponding module.

And the second difference value calculation module is used for calculating a historical SOH value corresponding to the historical discharge stage and a second difference value of the historical SOH value corresponding to the historical charge stage which is adjacent to the historical discharge stage in the backward direction.

And the second quotient calculation module is used for calculating a second quotient of the discharge duration included in the historical discharge data corresponding to the historical discharge stage of the second difference value, and taking the second quotient as an SOH normalized attenuation value corresponding to the historical discharge stage.

The second temperature interval corresponding module is configured to determine a temperature interval in which the average discharge temperature included in the historical discharge data corresponding to the historical discharge phase is located as a temperature interval corresponding to the historical discharge phase.

And the second SOH section corresponding module is used for determining the SOH section where the historical SOH value corresponding to the historical discharge stage is located as the SOH section corresponding to the historical discharge stage.

In one possible implementation, the SOH estimation module 303 may include: the system comprises a corresponding relation judging module, an SOH normalized attenuation value table look-up module, a target SOH attenuation value calculating module and an SOH estimated value calculating module.

The corresponding relation judging module is used for determining the corresponding relation under the target stage from the target corresponding relation, wherein the determined corresponding relation is a first corresponding relation if the target stage is a charging stage, and the determined corresponding relation is a second corresponding relation if the target stage is a discharging stage.

And the SOH normalized attenuation value table look-up module is used for searching a corresponding SOH normalized attenuation value from the corresponding relation under the target stage according to the SOH value at the last moment and the target temperature, and taking the searched SOH normalized attenuation value as a target SOH normalized attenuation value.

And the target SOH attenuation value calculation module is used for determining a target SOH attenuation value according to the target SOH normalized attenuation value and the target duration.

And the SOH estimated value calculation module is used for subtracting the SOH value at the last moment from the target SOH attenuation value, and taking the difference value as the SOH estimated value of the target battery at the current moment.

In one possible implementation manner, the power battery SOH estimation device provided by the embodiment of the application may further include: the device comprises a current charging data acquisition module, an SOH true value calculation module, an SOH estimation deviation calculation module and a corresponding relation update module.

The current charging data acquisition module is configured to acquire charging data of the target battery in a target time period, wherein if the current time is a charging stage time, the target time period is a time period in which the current whole charging stage is located, and if the current time is a discharging stage time, the target time period is a time period in which a last charging stage before the current time is located.

And the SOH real value calculation module is used for calculating the SOH real value of the target battery at the current moment according to the charging data of the target battery in the target time period and the factory rated capacity.

And the SOH estimation deviation calculation module is used for calculating the difference value between the SOH true value and the SOH estimation value.

And the corresponding relation updating module is used for judging whether the absolute value of the difference value is larger than a preset difference value threshold value, and if so, updating the corresponding relation based on the SOH true value and the charging data of the target battery in the target time period.

The embodiment of the application also provides a power battery SOH estimation device. Alternatively, fig. 4 shows a block diagram of a hardware structure of the power battery SOH estimation apparatus, and referring to fig. 4, the hardware structure of the power battery SOH estimation apparatus may include: at least one processor 401, at least one communication interface 402, at least one memory 403, and at least one communication bus 404;

in the embodiment of the present application, the number of the processor 401, the communication interface 402, the memory 403 and the communication bus 404 is at least one, and the processor 401, the communication interface 402 and the memory 403 complete communication with each other through the communication bus 404;

processor 401 may be a central processing unit CPU, or an Application-specific integrated Circuit ASIC (Application SPECIFIC INTEGRATED Circuit), or one or more integrated circuits configured to implement embodiments of the present invention, etc.;

The memory 403 may include a high-speed RAM memory, and may further include a non-volatile memory (non-volatile memory), etc., such as at least one magnetic disk memory;

Wherein the memory 403 stores a program, the processor 401 may call the program stored in the memory 403, the program being for:

Acquiring a pre-established corresponding relation between a power battery health state SOH section, a temperature section and an SOH normalized attenuation value, and taking the acquired corresponding relation as a target corresponding relation, wherein the target corresponding relation is obtained based on historical charge and discharge data respectively corresponding to a plurality of target types of power batteries on a real vehicle in a plurality of continuous historical charge and discharge stages, and the SOH normalized attenuation value is used for reflecting the attenuation degree of the SOH value of the power battery in the corresponding SOH section and the corresponding temperature section under the unit working time length;

Acquiring an SOH value of a target battery on a real vehicle at the last moment, and taking the acquired average temperature and the acquired phase duration of the target battery in a target phase as the target temperature and the target duration respectively, wherein the target battery is a power battery of a target type for which the SOH value needs to be estimated in real time, the last moment is the moment when the target phase is completed, and the target phase is the latest charging phase or discharging phase before the current moment;

Alternatively, the refinement function and the extension function of the program may be described with reference to the above.

The embodiment of the application also provides a readable storage medium, on which a computer program is stored, which when being executed by a processor, implements the power battery SOH estimation method as described above.

Finally, it is further noted that relational terms such as second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power cell SOH estimation method, characterized by comprising:

Acquiring a pre-established corresponding relation between a power battery health state SOH section, a temperature section and an SOH normalized attenuation value, and taking the acquired corresponding relation as a target corresponding relation, wherein the target corresponding relation is obtained based on historical charge and discharge data respectively corresponding to a plurality of target types of power batteries on a real vehicle in a plurality of continuous historical charge and discharge stages, and the SOH normalized attenuation value is used for reflecting the attenuation degree of the SOH value of the power battery in the corresponding SOH section and the corresponding temperature section in unit working time;

Acquiring an SOH value of a target battery on a real vehicle at the last moment, and taking the acquired average temperature and the acquired phase duration of the target battery under a target phase as the target temperature and the target duration respectively, wherein the target battery is a power battery of the target type for which the SOH value needs to be estimated in real time, the last moment is the moment when the target phase is completed, and the target phase is the last charging phase or discharging phase before the current moment;

And determining an SOH estimated value of the target battery at the current moment according to the target corresponding relation, the SOH value at the last moment, the target temperature and the target duration.

2. The SOH estimation method of a power battery according to claim 1, wherein the target correspondence includes a first correspondence in a charge phase and a second correspondence in a discharge phase;

The plurality of historical charge-discharge phases comprise a plurality of historical charge phases and a plurality of historical discharge phases, and the historical charge-discharge data respectively corresponding to the plurality of historical charge-discharge phases comprises historical charge data respectively corresponding to the plurality of historical charge phases and historical discharge data respectively corresponding to the plurality of historical discharge phases;

Acquiring historical charging data corresponding to the historical charging stages and historical discharging data corresponding to the historical discharging stages respectively, and acquiring factory rated capacity of the brand-new power battery of the target type;

For each of the plurality of historical charging phases, determining an SOH normalized attenuation value, a temperature interval, and an SOH interval corresponding to the historical charging phase according to a historical SOH value corresponding to the historical charging phase, a historical SOH value corresponding to a backward adjacent historical discharging phase of the historical charging phase, and historical charging data corresponding to the historical charging phase;

And determining the first corresponding relation according to SOH normalized attenuation values, temperature intervals and SOH intervals respectively corresponding to the plurality of historical charging stages.

3. The power battery SOH estimation method according to claim 2, characterized in that said obtaining the factory rated capacity of the brand-new power battery of the target type includes:

Calculating rated capacity under the multiple experimental conditions according to the discharge duration and the discharge current under the multiple experimental conditions;

Calculating the average value of the rated capacity under the multiple experimental conditions, and taking the average value as the factory rated capacity of the brand-new power battery of the target type, wherein the deviation between the rated capacity under each experimental condition and the average value is smaller than a preset deviation threshold value.

4. The method according to claim 2, wherein determining the historical SOH values for the plurality of historical charging phases and the plurality of discharging phases based on the historical charging data for the plurality of historical charging phases, the historical discharging data for the plurality of historical discharging phases, and the factory rated capacity, respectively, comprises:

For each of the plurality of historical charging stages, determining a battery capacity corresponding to the historical charging stage according to a historical charging duration, a historical charging current and a first state of charge (SOC) change value contained in historical charging data corresponding to the historical charging stage, and determining a historical SOH value corresponding to the historical charging stage according to the battery capacity corresponding to the historical charging stage and the factory rated capacity;

For each of the plurality of historical discharge phases, determining a battery capacity corresponding to the historical discharge phase according to a historical discharge duration, a historical discharge current and a second SOC variation value contained in historical discharge data corresponding to the historical discharge phase, and determining a historical SOH value corresponding to the historical discharge phase according to the battery capacity corresponding to the historical discharge phase and the factory rated capacity.

5. The method according to claim 2, wherein determining the SOH normalized attenuation value, the temperature interval, and the SOH interval corresponding to the historical charging stage according to the historical SOH value corresponding to the historical charging stage, the historical SOH value corresponding to the historical discharging stage adjacent to the historical charging stage, and the historical charging data corresponding to the historical charging stage comprises:

calculating a first quotient of the first difference and the charging duration contained in the historical charging data corresponding to the historical charging stage, and taking the first quotient as an SOH normalized attenuation value corresponding to the historical charging stage;

6. The SOH estimation method of claim 2, wherein the process of obtaining the second correspondence relation includes:

For each of the plurality of history discharge phases, determining an SOH normalized attenuation value, a temperature interval, and an SOH interval corresponding to the history discharge phase according to a history SOH value corresponding to the history discharge phase, a history SOH value corresponding to a history charge phase that is backward adjacent to the history discharge phase, and history discharge data corresponding to the history discharge phase;

And determining the second corresponding relation according to the SOH normalized attenuation value, the temperature interval and the SOH interval respectively corresponding to the historical discharge stages.

7. The method according to claim 6, wherein determining the SOH normalized attenuation value, the temperature interval, and the SOH interval corresponding to the history discharge phase according to the history SOH value corresponding to the history discharge phase, the history SOH value corresponding to the history charge phase that is backward adjacent to the history discharge phase, and the history discharge data corresponding to the history discharge phase comprises:

8. The SOH estimation method of a power battery according to claim 2, wherein the determining the SOH estimation value of the target battery at the current time based on the target correspondence, the SOH value at the previous time, the target temperature, and the target time length includes:

determining a corresponding relation under the target stage from the target corresponding relation, wherein the determined corresponding relation is the first corresponding relation if the target stage is a charging stage, and the determined corresponding relation is the second corresponding relation if the target stage is a discharging stage;

according to the SOH value at the last moment and the target temperature, searching a corresponding SOH normalized attenuation value from the corresponding relation in the target stage, and taking the searched SOH normalized attenuation value as a target SOH normalized attenuation value;

9. The SOH estimation method of a power cell according to claim 2, characterized by further comprising:

Acquiring charging data of the target battery in a target time period, wherein the target time period refers to a time period in which the current whole charging stage is located if the current time is a charging stage time, and refers to a time period in which the last charging stage before the current time is located if the current time is a discharging stage time;

Calculating a difference between the SOH actual value and the SOH estimated value;

And judging whether the absolute value of the difference is larger than a preset difference threshold value, if so, updating the corresponding relation based on the SOH true value and the charging data of the target battery in a target time period.

10. A power cell SOH estimation apparatus, characterized by comprising:

The corresponding relation acquisition module is used for acquiring a corresponding relation between a pre-established SOH section and a temperature section of the power battery and an SOH normalized attenuation value, and taking the acquired corresponding relation as a target corresponding relation, wherein the target corresponding relation is obtained based on historical charge and discharge data of a plurality of target types of power batteries on a real vehicle, which correspond to a plurality of continuous historical charge and discharge stages respectively, and the SOH normalized attenuation value is used for reflecting the attenuation degree of the SOH value of the power battery in the corresponding SOH section and the corresponding temperature section under the unit working time length;

The target data acquisition module is used for acquiring an SOH value of a target battery on a real vehicle at the last moment, and an average temperature and a stage duration of the target battery in a target stage, wherein the acquired average temperature and the acquired stage duration are respectively used as the target temperature and the target duration, the target battery is a power battery of the target type which needs to be subjected to real-time estimation of the SOH value, the last moment is the moment when the target stage is completed, and the target stage is the latest charging stage or discharging stage before the current moment;