CN109459704B - Compensation correction method and device for lithium ion battery capacity grading capacity - Google Patents
Compensation correction method and device for lithium ion battery capacity grading capacity Download PDFInfo
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Abstract
The invention is suitable for the technical field of battery capacity grading, and provides a method and a device for compensating and correcting capacity grading of a lithium ion battery, wherein the method comprises the following steps: under the standard temperature, performing discharge test on the batteries subjected to capacity grading and grouping, and simulating to obtain test data of the workshop batteries in the initial discharge state and the end discharge state; respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state according to the test data; collecting the capacity of the batteries subjected to capacity grading and grouping at different temperatures according to the same process step; according to the collected capacity grading capacity, and based on the first capacity compensation function and the second capacity compensation function, a third capacity compensation function of the workshop battery, which is affected by the temperature, is constructed; and compensating and correcting the capacity grading capacity of the workshop battery according to the first capacity compensation function, the second capacity compensation function and the third capacity compensation function, so that the accuracy of the capacity grading capacity of the battery is improved.
Description
Technical Field
The invention belongs to the technical field of battery capacity grading, and particularly relates to a method and a device for compensating and correcting capacity grading of a lithium ion battery.
Background
The capacity is the first attribute of the battery, and how to more accurately acquire the capacity of the battery is an important link in the battery production process. Accurate capacity measurement is the key to practical application such as capacity grading, effective low-capacity battery identification, production capacity abnormity early warning and the like. The capacity of the battery is easily influenced by factors such as temperature fluctuation of workshop environment, abnormal current and voltage of a formation cabinet, the battery and even the capacity grading step. Therefore, the difference of the capacity grading data of the workshop battery is large, and capacity misjudgment is easily caused.
At present, the capacity of the battery is obtained by directly forming and grading the capacity of the battery according to the actual process through a forming and grading cabinet. The specific values are easily affected by the battery itself, the instruments, the environment, and the capacity grading process. The method for improving the capacity grading precision is mainly to use equipment such as an air conditioner and the like to keep the environment constant temperature and use a higher-precision and better-performance capacity grading cabinet. The implementation of the two points brings higher cost to the production and reduces the product competitiveness. Most of the searched methods related to battery capacity correction and prediction are used for predicting and estimating the capacity under different conditions on the premise of accurate capacity test, and the problem of capacity error caused by capacity grading under the complex condition of a production workshop is solved, and the prior art is not researched
Disclosure of Invention
The embodiment of the invention provides a compensation and correction method for capacity grading of a lithium ion battery, and aims to solve the problem that capacity errors are generated by capacity grading under the complex condition of a workshop due to the fact that an effective compensation and correction method cannot be provided in the prior art.
The embodiment of the invention is realized in such a way that the method for compensating and correcting the capacity grading capacity of the lithium ion battery comprises the following steps:
under the standard temperature, performing discharge test on the batteries subjected to capacity grading and grouping, and simulating to obtain test data of the workshop batteries in the initial discharge state and the end discharge state;
respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state according to the test data;
collecting the capacity of the batteries subjected to capacity grading and grouping at different temperatures according to the same process step;
according to the collected capacity grading capacity, and based on the first capacity compensation function and the second capacity compensation function, a third capacity compensation function of the workshop battery, which is influenced by the temperature, is constructed;
and compensating and correcting the capacity grading of the workshop battery according to the first capacity compensation function, the second capacity compensation function and the third capacity compensation function.
Further, the step of performing a charge and discharge test on the batteries subjected to capacity grading at the standard temperature to obtain test data of the workshop battery in a discharge initial state and a discharge end state in a simulation manner specifically includes:
determining the model of a battery to be compensated, and acquiring the battery with the model which is subjected to capacity allocation;
under the standard temperature, carrying out interval discharge test of preset capacity on the battery, and enabling the balance state of a discharge interval to simulate the discharge initial state or the discharge ending state of the workshop battery;
and acquiring test data of the balance state of the discharge interval as test data of the workshop battery in the initial discharge state and the end discharge state.
Further, the test data includes a voltage of the battery and a corresponding discharge capacity;
the step of respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge end state according to the test data specifically comprises the following steps:
obtaining voltage capacity change curves of the workshop battery in the initial discharge state and the end discharge state according to the test data;
performing function fitting derivation on the voltage capacity change curve to obtain a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state;
the first capacity compensation function is:
y1＝ax+b；
the second capacity compensation function is:
wherein x is a voltage, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, a, b, A1、A2Is a coefficient of ya、t1、t2Are fitting parameters.
Further, the step of constructing a third capacity compensation function of the workshop battery, which is affected by the temperature, according to the collected capacity grading capacity and based on the first capacity compensation function and the second capacity compensation function specifically includes:
according to the first capacity compensation function and the second capacity compensation function, compensation calculation is carried out on the collected capacity grading capacity, and capacity difference of the workshop battery influenced by temperature is obtained;
constructing a third capacity compensation function of the workshop battery influenced by the temperature according to the capacity difference;
the third capacity compensation function is:
y3＝A3*F(T-T0)；
wherein, y3For the capacity to be compensated under the influence of temperature, A3Is a coefficient, T is a workshop temperature, T0As standard temperature, F (T-T)0) As a function of the temperature T.
Furthermore, the corrected capacity of the workshop battery is y;
y＝y0+(y1+y2+y3)；
wherein, y0To capacity, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, y3Is the capacity that needs to be compensated for under the influence of temperature.
The embodiment of the invention also provides a device for compensating and correcting the capacity grading of the lithium ion battery, which comprises:
the testing module is used for carrying out discharge testing on the batteries subjected to capacity grading at a standard temperature and simulating to obtain test data of the workshop batteries in a discharge initial state and a discharge finishing state;
the first function construction module is used for respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state according to the test data;
the collecting module is used for collecting the capacity of the batteries subjected to capacity grading and grouping according to the same process step at different temperatures;
the second function building module is used for building a third capacity compensation function of the workshop battery, which is influenced by the temperature, according to the collected capacity grading capacity and based on the first capacity compensation function and the second capacity compensation function;
and the compensation correction module is used for compensating and correcting the capacity grading capacity of the workshop battery according to the first capacity compensation function, the second capacity compensation function and the third capacity compensation function.
Furthermore, the test module specifically includes:
the battery obtaining unit is used for determining the type of a battery needing to be compensated and obtaining the battery with the type of the capacity-matched group;
the discharge testing unit is used for carrying out interval discharge testing of preset capacity on the battery at a standard temperature, so that the balance state of a discharge interval simulates the discharge initial state or the discharge ending state of the workshop battery;
and the data acquisition unit is used for acquiring the test data of the balance state of the discharge interval as the test data of the workshop battery in the initial discharge state and the end discharge state.
Further, the test data includes a voltage of the battery and a corresponding discharge capacity;
the first function building module specifically includes:
the curve obtaining unit is used for obtaining voltage capacity change curves of the workshop battery in a discharge initial state and a discharge finishing state according to the test data;
the function obtaining unit is used for carrying out function fitting derivation on the voltage capacity change curve to obtain a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state;
the first capacity compensation function is:
y1＝ax+b；
the second capacity compensation function is:
wherein x is a voltage, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, a, b, A1、A2Is a coefficient of ya、t1、t2Are fitting parameters.
Further, the second function building module specifically includes:
the compensation calculation unit is used for performing compensation calculation on the collected capacity grading capacity according to a first capacity compensation function and the second capacity compensation function to obtain the capacity difference of the workshop battery influenced by the temperature;
the function construction unit is used for constructing a third capacity compensation function of the workshop battery, which is influenced by the temperature, according to the capacity difference;
the third capacity compensation function is:
y3＝A3*F(T-T0)；
wherein, y3For the capacity to be compensated under the influence of temperature, A3Is a coefficient, T is a workshop temperature, T0As standard temperature, F (T-T)0) As a function of the temperature T.
Furthermore, the corrected capacity of the workshop battery is y;
y＝y0+(y1+y2+y3)；
wherein, y0To capacity, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, y3Is the capacity that needs to be compensated for under the influence of temperature.
In the embodiment of the invention, through a discharge test of a capacity-divided battery in a group at a standard temperature, test data of a workshop battery in a discharge initial state and a discharge end state are obtained in a simulation mode to construct a corresponding first capacity compensation function and a second capacity compensation function, further, according to the two capacity compensation functions and the capacity division capacities of the capacity-divided battery in the group at different temperatures, the influence of the temperature on the capacity division capacity is obtained, and a third capacity compensation function is constructed, so that the capacity division capacity of the workshop battery is compensated according to the three capacity compensation functions, and the capacity supplement correction with higher progress is achieved.
Drawings
Fig. 1 is a flowchart illustrating an implementation of a method for compensating and correcting capacity grading of a lithium ion battery according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a compensation and correction device for capacity grading of a lithium ion battery according to a second embodiment of the present invention;
fig. 3 is a schematic diagram of a preferred structure of a compensation and correction device for capacity grading of a lithium ion battery according to a second embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
According to the invention, the capacity grading capacity of the workshop battery is compensated and corrected by constructing the first capacity compensation function in the initial discharge state of the workshop battery, the second capacity compensation function in the end discharge state of the workshop battery and the third capacity compensation function under the influence of temperature, so that the problem of capacity error caused by grading under the complex workshop condition in the prior art is solved.
Example one
Fig. 1 shows an implementation flow of a compensation and correction method for capacity grading of a lithium ion battery according to a first embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, which are detailed as follows:
in step S101, a discharge test is performed on the capacity-matched batteries at a standard temperature, and test data of the workshop battery in a discharge initial state and a discharge end state are obtained through simulation.
In the embodiment of the invention, firstly, the model of the research battery is determined according to actual needs, and the leased batteries with different capacities of the model are obtained, and preferably 4 to 8 batteries are obtained. Furthermore, under the standard temperature (the standard temperature is 25 ℃, and the environmental temperature is kept at 25 +/-2 ℃ under the actual condition), a test cabinet with higher precision is adopted, and the discharge test is carried out on the obtained battery according to certain steps. The discharge test means that the fully charged battery is discharged to 2.75V at a tiny capacity interval, each discharge interval needs to be kept for a certain time to reach an equilibrium state, and the equilibrium state of the discharge interval can approximately simulate different states of the workshop battery, namely the discharge interval can be in one-to-one correspondence with the initial discharge state and the end discharge state of the workshop battery.
After the balance state corresponds to the initial discharge state and the end discharge state of the workshop battery, the test data in the balance state of the discharge interval is obtained, and the test data in the initial discharge state and the end discharge state of the workshop battery corresponding to the test data can be obtained. Preferably, the test data includes the voltage and discharge capacity of the workshop battery under different conditions.
In step S102, a first capacity compensation function of the workshop battery in the initial discharge state and a second capacity compensation function of the workshop battery in the end discharge state are respectively constructed according to the test data.
In the embodiment of the invention, the voltage capacity change curves of the workshop battery in the initial discharge state and the end discharge state can be constructed according to the test data of the workshop battery in the initial discharge state and the end discharge state. And performing function fitting derivation on the voltage capacity change curve, and determining a function with higher fitting degree by auxiliary software, wherein the relevance degree of the fitting function is recommended to be more than 99%. And obtaining a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function in a discharge end state through fitting derivation.
Wherein the first capacity compensation function is y1Ax + b, the second capacity compensation function being
x is a voltage, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, a, b, A1、A2Is a coefficient of ya、t1、t2As fitting parameters, fitting can be performed.
In step S103, the capacity of the batteries subjected to capacity grading at different temperatures according to the same process step is collected.
In the embodiment of the invention, 10-20pcs of a rated and assembled battery with a set model are obtained, capacity grading is carried out in a workshop and a test room according to the same capacity grading process step, capacity grading data correspond to each other one by one, and the temperature of the corresponding environment is recorded, so that the capacity grading capacity of the battery at different temperatures in the workshop is obtained. Among them, it is preferable to test the temperature range of [20 ℃, 40 ℃ C ] in the production plant.
In step S104, a third capacity compensation function of the workshop battery affected by the temperature is constructed according to the collected capacity grading capacity and based on the first capacity compensation function and the second capacity compensation function.
In the embodiment of the invention, the collected capacity grading capacity is compensated and calculated according to the first capacity compensation function and the second capacity compensation function, and the capacity difference of the workshop battery influenced by the temperature is obtained, so that the influence of the temperature on the capacity grading capacity is obtained. The first capacity compensation function and the second capacity compensation function eliminate a part of the measurement errors of the collected capacity so as to more conveniently and accurately research the influence of the temperature on the capacity.
And further constructing a third capacity compensation function of the workshop battery influenced by the temperature according to the capacity difference. The influence of the workshop temperature on the battery capacity can be solved according to the third capacity compensation function, and the ranges of the capacity temperature [20 ℃, 40 ℃ and the like ] are quantitatively calculated.
Wherein the third capacity compensation function is y3＝A3*F(T-T0)。y3For the capacity to be compensated under the influence of temperature, A3Is a coefficient, T is a workshop temperature, T0As standard temperature, F (T-T)0) As a function of the temperature T.
In step S105, the capacity of the workshop battery is compensated and corrected according to the first capacity compensation function, the second capacity compensation function, and the third capacity compensation function.
In the embodiment of the invention, the first capacity compensation function, the second capacity compensation function and the third capacity compensation function respectively compensate three aspects of the difference source of the workshop battery capacity, so that the correction function of the workshop battery capacity can be constructed by combining the actual state of the workshop battery.
Wherein the correction function is y ═ y0+(y1+y2+y3). y is the compensated corrected capacity, y0To capacity, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, y3Is the capacity that needs to be compensated for under the influence of temperature.
Based on the capacity of the workshop section, a calculation program is added, the capacity after the compensation and the correction of the battery capacity can be obtained, and the capacity of the section at 25 ℃ can be obtained by considering the temperature compensation, so that the standard capacity of the battery can be predicted in the embodiment.
As shown in table 1, after the correction function is constructed, the correction function is used to verify test data of a plant, a test center, and the like. And the charge and discharge capacity data of the first test center is the capacity in the standard state, and the charge and discharge capacity data of the second workshop and the charge and discharge capacity data of the third test center are the capacities corresponding to the standard state after the capacity in the standard state is compensated according to the correction function. If the capacity in the workshop state is compensated according to the correction function, the corrected capacity in the workshop state can be obtained. Through verification, the capacity of the workshop battery is corrected and compensated according to the capacity grading capacity of the workshop battery, and the precision of the capacity grading capacity is effectively improved.
TABLE 1
The capacity compensation function can be constructed to respectively perform capacity compensation correction corresponding to three major parts of the capacity difference of the workshop battery capacity grading, so that the method is suitable for the complex environment of a production workshop, and the purpose of improving the capacity grading precision is achieved; the method is characterized in that the capacity difference research of different temperatures and multiplying powers is carried out on batteries of specific models, the capacity prediction among different temperatures and/or multiplying powers is achieved, and the method can be applied to the aspects of capacity grading, low-capacity battery identification, production capacity abnormity early warning and the like; in the implementation process, the data determination needs to count the batch data of the batteries with specific models, and the adjustment and determination are carried out according to the actual situation, so that the capacity compensation correction with higher precision is achieved.
Example two
Fig. 2 is a schematic structural diagram of a compensation and correction device for capacity grading of a lithium ion battery according to a second embodiment of the present invention, and for convenience of description, only a part related to the second embodiment of the present invention is shown, where the structure includes: a test module 21, a first function building module 22, a collection module 23, a second function building module 24 and a compensation modification module 25, wherein:
and the test module 21 is used for performing discharge test on the batteries subjected to capacity allocation at a standard temperature, and simulating to obtain test data of the workshop batteries in a discharge initial state and a discharge finishing state.
In the embodiment of the invention, firstly, the model of the research battery is determined according to actual needs, and the leased batteries with different capacities of the model are obtained, and preferably 4 to 8 batteries are obtained. Furthermore, under the standard temperature (the standard temperature is 25 ℃, and the environmental temperature is kept at 25 +/-2 ℃ under the actual condition), a test cabinet with higher precision is adopted, and the discharge test is carried out on the obtained battery according to certain steps. The discharge test means that the fully charged battery is discharged to 2.75V at a tiny capacity interval, each discharge interval needs to be kept for a certain time to reach an equilibrium state, and the equilibrium state of the discharge interval can approximately simulate different states of the workshop battery, namely the discharge interval can be in one-to-one correspondence with the initial discharge state and the end discharge state of the workshop battery.
After the balance state corresponds to the initial discharge state and the end discharge state of the workshop battery, the test data in the balance state of the discharge interval is obtained, and the test data in the initial discharge state and the end discharge state of the workshop battery corresponding to the test data can be obtained. Preferably, the test data includes the voltage and discharge capacity of the workshop battery under different conditions.
And the first function construction module 22 is used for respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state according to the test data.
In the embodiment of the invention, the voltage capacity change curves of the workshop battery in the initial discharge state and the end discharge state can be constructed according to the test data of the workshop battery in the initial discharge state and the end discharge state. And performing function fitting derivation on the voltage capacity change curve, and determining a function with higher fitting degree by auxiliary software, wherein the relevance degree of the fitting function is recommended to be more than 99%. And obtaining a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function in a discharge end state through fitting derivation.
Wherein the first capacity compensation function is y1Ax + b, the second capacity compensation function being
x is a voltage, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, a, b, A1、A2Is a coefficient of ya、t1、t2As fitting parameters, fitting can be performed.
And the collecting module 23 is used for collecting the capacity of the batteries subjected to capacity grading at different temperatures according to the same process step.
In the embodiment of the invention, 10-20pcs of a rated and assembled battery with a set model are obtained, capacity grading is carried out in a workshop and a test room according to the same capacity grading process step, capacity grading data correspond to each other one by one, and the temperature of the corresponding environment is recorded, so that the capacity grading capacity of the battery at different temperatures in the workshop is obtained. Among them, it is preferable to test the temperature range of [20 ℃, 40 ℃ C ] in the production plant.
And a second function construction module 24, configured to construct a third capacity compensation function of the workshop battery, which is affected by the temperature, according to the collected capacity grading capacities and based on the first capacity compensation function and the second capacity compensation function.
In the embodiment of the invention, the collected capacity grading capacity is compensated and calculated according to the first capacity compensation function and the second capacity compensation function, and the capacity difference of the workshop battery influenced by the temperature is obtained, so that the influence of the temperature on the capacity grading capacity is obtained. The first capacity compensation function and the second capacity compensation function eliminate a part of the measurement errors of the collected capacity so as to more conveniently and accurately research the influence of the temperature on the capacity.
And further constructing a third capacity compensation function of the workshop battery influenced by the temperature according to the capacity difference. The influence of the workshop temperature on the battery capacity can be solved according to the third capacity compensation function, and the ranges of the capacity temperature [20 ℃, 40 ℃ and the like ] are quantitatively calculated.
Wherein the third capacity compensation function is y3＝A3*F(T-T0)。y3For the capacity to be compensated under the influence of temperature, A3Is a coefficient, T is a workshop temperature, T0As standard temperature, F (T-T)0) As a function of the temperature T.
And the compensation correction module 25 is configured to perform compensation correction on the capacity division capacity of the workshop battery according to the first capacity compensation function, the second capacity compensation function, and the third capacity compensation function.
In the embodiment of the invention, the first capacity compensation function, the second capacity compensation function and the third capacity compensation function respectively compensate three aspects of the difference source of the workshop battery capacity, so that the correction function of the workshop battery capacity can be constructed by combining the actual state of the workshop battery.
Wherein the correction function is y ═ y0+(y1+y2+y3). y is the compensated corrected capacity, y0To capacity, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, y3Is the capacity that needs to be compensated for under the influence of temperature.
Based on the capacity of the workshop section, a calculation program is added, the capacity after the compensation and the correction of the battery capacity can be obtained, and the capacity of the section at 25 ℃ can be obtained by considering the temperature compensation, so that the standard capacity of the battery can be predicted in the embodiment.
As shown in fig. 3, preferably, the test module 21 specifically includes:
a battery obtaining unit 211, configured to determine a model of a battery to be compensated, and obtain a battery of the model that has been subjected to capacity matching;
the discharge test unit 212 is used for carrying out interval discharge test of preset capacity on the battery at a standard temperature, so that the balance state of a discharge interval simulates the discharge initial state or the discharge ending state of a workshop battery;
the data acquiring unit 213 is configured to acquire test data of the balance state of the discharge interval as test data of the workshop battery in the discharge initial state and the discharge end state.
The first function building module 22 specifically includes:
the curve obtaining unit 221 is configured to obtain voltage capacity change curves of the workshop battery in the initial discharge state and the end discharge state according to the test data;
a function obtaining unit 222, configured to perform function fitting derivation on the voltage-capacity variation curve to obtain a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge end state;
the first capacity compensation function is:
y1＝ax+b；
the second capacity compensation function is:
wherein x is a voltage, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, a, b, A1、A2Is a coefficient of ya、t1、t2Are fitting parameters.
The second function building module 24 specifically includes:
the compensation calculation unit 241 is used for performing compensation calculation on the collected capacity grading capacity according to a first capacity compensation function and the second capacity compensation function to obtain a capacity difference of the workshop battery influenced by the temperature;
a function constructing unit 242, configured to construct a third capacity compensation function of the workshop battery, which is affected by the temperature, according to the capacity difference;
the third capacity compensation function is:
y3＝A3*F(T-T0)；
wherein, y3For the capacity to be compensated under the influence of temperature, A3Is a coefficient, T is a workshop temperature, T0As standard temperature, F (T-T)0) As a function of the temperature T.
The capacity compensation function can be constructed to respectively perform capacity compensation correction corresponding to three major parts of the capacity difference of the workshop battery capacity grading, so that the method is suitable for the complex environment of a production workshop, and the purpose of improving the capacity grading precision is achieved; the method is characterized in that the capacity difference research of different temperatures and multiplying powers is carried out on batteries of specific models, the capacity prediction among different temperatures and/or multiplying powers is achieved, and the method can be applied to the aspects of capacity grading, low-capacity battery identification, production capacity abnormity early warning and the like; in the implementation process, the data determination needs to count the batch data of the batteries with specific models, and the adjustment and determination are carried out according to the actual situation, so that the capacity compensation correction with higher precision is achieved.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (8)
1. A method for compensating and correcting capacity grading of a lithium ion battery is characterized by comprising the following steps:
under the standard temperature, performing discharge test on the batteries subjected to capacity grading and grouping, and simulating to obtain test data of the workshop batteries in the initial discharge state and the end discharge state;
respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state according to the test data;
collecting the capacity of the batteries subjected to capacity grading and grouping at different temperatures according to the same process step;
according to the collected capacity grading capacity, and based on the first capacity compensation function and the second capacity compensation function, a third capacity compensation function of the workshop battery, which is influenced by the temperature, is constructed;
according to the first capacity compensation function, the second capacity compensation function and the third capacity compensation function, compensating and correcting the capacity grading capacity of the workshop battery;
the test data comprises the voltage of the battery and the corresponding discharge capacity;
the step of respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge end state according to the test data specifically comprises the following steps:
obtaining voltage capacity change curves of the workshop battery in the initial discharge state and the end discharge state according to the test data;
performing function fitting derivation on the voltage capacity change curve to obtain a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state;
the first capacity compensation function is:
y1＝ax+b；
the second capacity compensation function is:
wherein x is a voltage, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, a, b, A1、A2Is a coefficient of ya、t1、t2Are fitting parameters.
2. The method for compensating and correcting capacity grading of a lithium ion battery according to claim 1, wherein the step of performing a charge and discharge test on the batteries subjected to capacity grading and grouping at a standard temperature to obtain test data of the workshop battery in a discharge initial state and a discharge end state in a simulation manner specifically comprises:
determining the model of a battery to be compensated, and acquiring the battery with the model which is subjected to capacity allocation;
under the standard temperature, carrying out interval discharge test of preset capacity on the battery, and enabling the balance state of a discharge interval to simulate the discharge initial state or the discharge ending state of the workshop battery;
and acquiring test data of the balance state of the discharge interval as test data of the workshop battery in the initial discharge state and the end discharge state.
3. The method for compensating and correcting capacity grading of a lithium ion battery according to claim 1, wherein the step of constructing a third capacity compensation function of the workshop battery, which is affected by temperature, based on the collected capacity grading capacity and the first and second capacity compensation functions specifically comprises:
according to the first capacity compensation function and the second capacity compensation function, compensation calculation is carried out on the collected capacity grading capacity, and capacity difference of the workshop battery influenced by temperature is obtained;
constructing a third capacity compensation function of the workshop battery influenced by the temperature according to the capacity difference;
the third capacity compensation function is:
y3＝A3*F(T-T0)；
wherein, y3For the capacity to be compensated under the influence of temperature, A3Is a coefficient, T is a workshop temperature, T0As standard temperature, F (T-T)0) As a function of the temperature T.
4. The method for compensating and correcting capacity grading of a lithium ion battery according to claim 1, wherein the corrected capacity of the workshop battery is y;
y＝y0+(y1+y2+y3)；
wherein, y0To capacity, y1Is in an initial stateCapacity, y, to be compensated2Capacity to be compensated for end state, y3Is the capacity that needs to be compensated for under the influence of temperature.
5. A device for compensating and correcting capacity grading of a lithium ion battery, the device comprising:
the testing module is used for carrying out discharge testing on the batteries subjected to capacity grading at a standard temperature and simulating to obtain test data of the workshop batteries in a discharge initial state and a discharge finishing state;
the first function construction module is used for respectively constructing a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state according to the test data;
the collecting module is used for collecting the capacity of the batteries subjected to capacity grading and grouping according to the same process step at different temperatures;
the second function building module is used for building a third capacity compensation function of the workshop battery, which is influenced by the temperature, according to the collected capacity grading capacity and based on the first capacity compensation function and the second capacity compensation function;
the compensation correction module is used for compensating and correcting the capacity grading capacity of the workshop battery according to the first capacity compensation function, the second capacity compensation function and the third capacity compensation function;
the test data comprises the voltage of the battery and the corresponding discharge capacity;
the first function building module specifically includes:
the curve obtaining unit is used for obtaining voltage capacity change curves of the workshop battery in a discharge initial state and a discharge finishing state according to the test data;
the function obtaining unit is used for carrying out function fitting derivation on the voltage capacity change curve to obtain a first capacity compensation function of the workshop battery in a discharge initial state and a second capacity compensation function of the workshop battery in a discharge finishing state;
the first capacity compensation function is:
y1＝ax+b；
the second capacity compensation function is:
wherein x is a voltage, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, a, b, A1、A2Is a coefficient of ya、t1、t2Are fitting parameters.
6. The device for compensating and correcting capacity grading of a lithium ion battery according to claim 5, wherein the test module specifically comprises:
the battery obtaining unit is used for determining the type of a battery needing to be compensated and obtaining the battery with the type of the capacity-matched group;
the discharge testing unit is used for carrying out interval discharge testing of preset capacity on the battery at a standard temperature, so that the balance state of a discharge interval simulates the discharge initial state or the discharge ending state of the workshop battery;
and the data acquisition unit is used for acquiring the test data of the balance state of the discharge interval as the test data of the workshop battery in the initial discharge state and the end discharge state.
7. The device for compensating and correcting capacity grading of a lithium ion battery according to claim 5, wherein the second function constructing module specifically comprises:
the compensation calculation unit is used for performing compensation calculation on the collected capacity grading capacity according to a first capacity compensation function and the second capacity compensation function to obtain the capacity difference of the workshop battery influenced by the temperature;
the function construction unit is used for constructing a third capacity compensation function of the workshop battery, which is influenced by the temperature, according to the capacity difference;
the third capacity compensation function is:
y3＝A3*F(T-T0)；
wherein, y3For the capacity to be compensated under the influence of temperature, A3Is a coefficient, T is a workshop temperature, T0As standard temperature, F (T-T)0) As a function of the temperature T.
8. The lithium ion battery capacity grading compensation and correction device according to claim 5, wherein the corrected capacity of the workshop battery is y;
y＝y0+(y1+y2+y3)；
wherein, y0To capacity, y1Capacity to be compensated for in the initial state, y2Capacity to be compensated for end state, y3Is the capacity that needs to be compensated for under the influence of temperature.
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| CN112034368A (en) * | 2020-08-24 | 2020-12-04 | 中兴高能技术有限责任公司 | Battery capacity calibration method and device |
| CN112034369A (en) * | 2020-08-24 | 2020-12-04 | 中兴高能技术有限责任公司 | Method and device for determining battery capacity |
| CN115166548B (en) * | 2022-07-13 | 2023-04-07 | 楚能新能源股份有限公司 | Temperature-sensitive power lithium battery capacity test compensation method |
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