Method, device and equipment for evaluating pulse discharge performance of lithium ion battery

Abstract

The invention discloses a method, a device and equipment for evaluating pulse discharge performance of a lithium ion battery, and relates to the technical field of power batteries, and the method comprises the following steps: calculating the pulse discharge performance of the lithium ion battery based on the relation between the cell working voltage and the pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time; constructing a corresponding pulse discharge current optimization model; solving the pulse discharge current optimization model to obtain the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell under each characteristic pulse time, and determining pulse discharge performance data of the battery cell; and evaluating and verifying the pulse discharge performance data of the battery cell, and formulating a pulse discharge MAP. Through the mode, the maximum pulse discharge current of the battery cell at different pulse times, different temperatures and different charge states is accurately determined, the pulse discharge capability of the battery cell is rapidly and accurately evaluated, and the pulse discharge MAP and the pulse discharge strategy of the battery cell are formulated.

Description

Technical Field

[0001] The present application relates to the field of power battery technology, and in particular to a method, device and equipment for evaluating the pulse discharge performance of a lithium-ion battery. Background Art

[0002] The pulse discharge power of a lithium-ion battery characterizes the short-time discharge capability of the battery cell. The size of the pulse discharge current directly determines the pulse discharge power. Therefore, the key to evaluating the pulse discharge performance of a lithium-ion battery is to determine the maximum pulse discharge current of the lithium-ion battery to ensure the safety of the battery cell throughout its life cycle, thereby enabling the power battery to operate safely and efficiently.

[0003] In the prior art, there are few studies on methods for quickly evaluating the continuous discharge current of lithium-ion batteries, and the evaluation of the continuous discharge performance of lithium-ion batteries has problems such as many test conditions, long test cycles, and high test resources and labor costs.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of this application is to provide a method, device and equipment for evaluating the pulse discharge performance of lithium-ion batteries, aiming to solve the technical problems that the traditional methods of evaluating the pulse discharge performance of lithium-ion batteries in the prior art are relatively complex, costly, and difficult to achieve quickly and accurately.

[0006] To achieve the above objectives, the present application provides a method for evaluating the pulse discharge performance of a lithium-ion battery, the method comprising:

[0007] Setting a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, setting a plurality of characteristic charge states within the charge state range, and setting a plurality of characteristic pulse times;

[0008] Based on the relationship between the cell operating voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, a corresponding pulse discharge current optimization model is constructed;

[0009] Initialize the pulse discharge current of chromosomes in the population and construct a fitness function;

[0010] Based on the fitness function, the chromosomes in the population are divided into elite individuals and non-elite individuals, and new individuals with new pulse discharge currents are generated based on the elite individuals and non-elite individuals. The new individuals are combined with the elite individuals to generate a new population, and the iteration is continuously performed until the iteration termination condition is met to obtain the target population;

[0011] The maximum value of the pulse discharge current of the chromosome in the target population is taken as the solution of the corresponding pulse discharge current optimization model, and the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time is obtained;

[0012] Determine the pulse discharge performance data of the battery cell based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0013] Evaluate and verify pulse discharge performance data and develop pulse discharge MAP.

[0014] In one embodiment, the pulse discharge current optimization model includes at least the following constraints:

[0015] The working voltage of the battery cell is equal to the open circuit voltage at the initial moment of discharge minus the product of the dynamic internal resistance of the battery cell and the pulse discharge current;

[0016] The dynamic internal resistance of the battery cell is equal to the sum of the ohmic internal resistance and the polarization internal resistance;

[0017] The dynamic internal resistance of the battery cell conforms to the fitted internal resistance function relationship;

[0018] The working voltage of the battery cell at the end of discharge is greater than or equal to the discharge cut-off voltage;

[0019] The pulse discharge current is greater than zero;

[0020] The relationship between the cell operating voltage and pulse discharge current satisfies a linear relationship;

[0021] The temperature rise of the battery cell during a single pulse is less than or equal to the preset temperature rise safety threshold.

[0022] In one embodiment, based on the fitness function, the step of dividing chromosomes in the population into elite individuals and non-elite individuals includes:

[0023] Based on the fitness function and the pulse discharge current of the chromosomes in the population, the fitness value of the chromosomes in the population is calculated;

[0024] Based on the fitness values ​​of the chromosomes in the population, the chromosomes in the population are sorted in descending order to obtain the individual sequence of the population;

[0025] Based on the preset elite ratio, elite individuals are determined in the individual sequence of the population;

[0026] Based on the elite individuals of the population, determine the non-elite individuals of the population.

[0027] In one embodiment, the step of generating a new individual with a new pulse discharge current based on the elite individual and the non-elite individual includes:

[0028] Based on the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual, a cross pulse discharge current is generated;

[0029] The pulse discharge current of the non-elite individuals is disturbed to determine the disturbed pulse discharge current;

[0030] The cross pulse discharge current and the disturbance pulse discharge current are taken as new pulse discharge currents, and a new individual with the new pulse discharge current is determined.

[0031] In one embodiment, the step of generating a cross pulse discharge current based on the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual includes:

[0032] The pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual are cross-processed based on the cross-over rate to obtain the cross-pulse discharge current.

[0033] In one embodiment, the pulse discharge current of the non-elite individual is disturbed, and the step of determining the disturbed pulse discharge current includes:

[0034] Based on a preset number of selections, the disturbance individuals are determined among the non-elite individuals;

[0035] Obtaining a first corresponding relationship between a disturbance intensity, a scaling factor, a random value, a pulse discharge current and a disturbance pulse discharge current;

[0036] The disturbance pulse discharge current is determined based on the disturbance intensity, the scaling factor, the random value, the pulse discharge current of the disturbance individual and the first corresponding relationship.

[0037] In one embodiment, the method further comprises:

[0038] Obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0039] Obtaining a second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the pulse discharge current and the temperature rise of the battery cell after a single pulse;

[0040] Based on the second corresponding relationship, the specific heat capacity of the battery cell, the battery cell mass, and the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, the single pulse battery cell temperature rise corresponding to the pulse discharge current under different characteristic pulse times, different characteristic temperatures and different characteristic states of charge is determined.

[0041] In one embodiment, the steps of evaluating and verifying the pulse discharge performance data of the battery cell and formulating the corresponding pulse discharge MAP include:

[0042] Set multiple verification temperatures, multiple verification states of charge, and multiple verification pulse times;

[0043] Based on the maximum pulse discharge current corresponding to different verification temperatures and different verification states of charge at each verification pulse time, the battery cell is subjected to a cyclic charge and discharge test, and the state of the battery cell after the cyclic charge and discharge test is completed is determined;

[0044] When the state of the battery cell meets the verification requirements, determine that the pulse discharge performance data of the battery cell is reasonable, and formulate corresponding pulse discharge MAP and pulse discharge strategy.

[0045] In addition, to achieve the above purpose, the present application also proposes a device for evaluating the pulse discharge performance of a lithium-ion battery, the device comprising:

[0046] A parameter division module, used to set a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, set a plurality of characteristic charge states within the charge state range, and set a plurality of characteristic pulse times;

[0047] A data calculation module is used to construct a corresponding pulse discharge current optimization model based on the relationship between the cell operating voltage and the pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0048] The data calculation module is also used to initialize the pulse discharge current of chromosomes in the population and construct the fitness function;

[0049] The data calculation module is also used to divide the chromosomes in the population into elite individuals and non-elite individuals based on the fitness function, and generate new individuals with new pulse discharge currents based on the elite individuals and non-elite individuals, and combine the new individuals with the elite individuals to generate a new population, and iterate continuously until the iteration termination condition is met to obtain the target population;

[0050] The data calculation module is also used to take the maximum value of the pulse discharge current of the chromosome in the target population as the solution of the corresponding pulse discharge current optimization model, and obtain the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0051] The data calculation module is also used to determine the pulse discharge performance data of the battery cell based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0052] The evaluation and verification module is used to evaluate and verify the pulse discharge performance data and formulate the pulse discharge MAP.

[0053] In addition, to achieve the above-mentioned purpose, the present application also proposes a device for evaluating the pulse discharge performance of a lithium-ion battery. The device for evaluating the pulse discharge performance of a lithium-ion battery includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. The computer program is configured to implement the steps of the method for evaluating the pulse discharge performance of a lithium-ion battery as described above.

[0054] In addition, to achieve the above-mentioned purpose, the present invention also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the method for evaluating the pulse discharge performance of a lithium-ion battery as described above are implemented.

[0055] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of the method for evaluating the pulse discharge performance of a lithium-ion battery as described above are implemented.

[0056] The present application provides a method for evaluating the pulse discharge performance of a lithium-ion battery, which includes setting a plurality of characteristic temperatures within the operating temperature range of a cell in the lithium-ion battery, setting a plurality of characteristic charge states within the charge state range, and setting a plurality of characteristic pulse times; constructing a corresponding pulse discharge current optimization model based on the relationship between the cell operating voltage and the pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time; initializing the pulse discharge current of chromosomes in a population, and constructing a fitness function; based on the fitness function, dividing the chromosomes in the population into elite individuals and non-elite individuals, and generating a fitness function based on the elite individuals and the non-elite individuals. There are new individuals with new pulse discharge currents. The new individuals are combined with elite individuals to generate a new population, and iterate continuously until the iteration termination condition is met to obtain the target population; the maximum value of the pulse discharge current of the chromosome in the target population is used as the solution of the corresponding pulse discharge current optimization model to obtain the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time; based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time, the pulse discharge performance data of the battery cell is determined; the pulse discharge performance data is evaluated and verified, and a pulse discharge MAP is formulated. This application uses the relationship between the working voltage of the battery cell and the pulse discharge current to construct a pulse discharge current optimization model. By solving the model, the maximum pulse discharge current under different pulse times, different temperatures, and different charge states is found, and the pulse discharge capability of the battery cell is quickly and accurately evaluated. At the same time, based on the pulse discharge capability of the battery cell, the pulse discharge MAP and pulse discharge strategy of the battery cell are formulated to ensure the safety of the battery cell throughout its life cycle and realize safe and efficient operation of the power battery. This solves the technical problem that the traditional method of evaluating the pulse discharge performance of lithium-ion batteries is relatively complex, costly, and difficult to achieve quickly and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0058] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0059] Figure 1 This is a flow chart of Example 1 of a method for evaluating pulse discharge performance of a lithium-ion battery of the present application;

[0060] Figure 2This is a flow chart of Embodiment 2 of the method for evaluating the pulse discharge performance of a lithium-ion battery of the present application;

[0061] Figure 3 This is a schematic diagram of the module structure of a device for evaluating the pulse discharge performance of a lithium-ion battery according to an embodiment of the present application;

[0062] Figure 4 Schematic diagram of the equipment structure of the hardware operating environment involved in the method for evaluating the pulse discharge performance of a lithium-ion battery in an embodiment of the present application.

[0063] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0064] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0065] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0066] It should be noted that the execution subject of this embodiment can be a computing service device with data processing, network communication and program running functions, such as a tablet computer, a personal computer, a mobile phone, etc., or an electronic device capable of realizing the above functions, a lithium-ion battery pulse discharge performance evaluation device, etc., and this embodiment does not specifically limit this. The following takes the lithium-ion battery pulse discharge performance evaluation device as an example to illustrate this embodiment and the following embodiments.

[0067] The present application embodiment provides a method for evaluating the pulse discharge performance of a lithium-ion battery, referring to Figure 1 , Figure 1 This is a flow chart of the first embodiment of the method for evaluating the pulse discharge performance of a lithium-ion battery of the present application.

[0068] In this embodiment, the method for evaluating the pulse discharge performance of a lithium-ion battery includes steps S10 to S70:

[0069] Step S10, setting a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, setting a plurality of characteristic charge states within the charge state range, and setting a plurality of characteristic pulse times;

[0070] It should be noted that the operating temperature range of the battery cell usually refers to the temperature range in which the battery cell works normally, which can be set according to actual conditions and is not specifically limited. The battery cell in this embodiment is a lithium-ion battery cell. The characteristic temperature refers to the pre-set operating temperature of the battery cell, which is used as the operating temperature for subsequent tests. Usually, multiple temperatures can be set. The specific values ​​and quantities can be set according to actual needs and are not specifically limited. For example, the characteristic temperatures are set to 40°C, 25°C, 10°C, 0°C, -10°C, and -20°C.

[0071] In addition, it should be noted that the state of charge range refers to the range of the state of charge (SOC) of the battery cell, usually 0 to 100%. The characteristic state of charge refers to the pre-set SOC value of the battery cell, which is used as the SOC value for subsequent tests. Usually, multiple values ​​can be set. The characteristic state of charge can be selected by setting the SOC gradient. According to the SOC gradient, the characteristic state of charge of the corresponding value is selected within the state of charge range. For example, if the set SOC gradient is ΔSOC, then SOC i =i·ΔSOC, where i is the i-th SOC value, SOC1=0 is the minimum SOC value of the battery cell, and SOC j =100% is the maximum SOC value of the battery cell, 0≤i≤j.

[0072] It is understood that the characteristic pulse time refers to the pre-set pulse time, which is also the duration of the pulse current. Usually, multiple pulse times can be set, and the set characteristic pulse time is used as the pulse time for subsequent tests. The characteristic pulse time can be a short pulse, a standard pulse, or a long pulse. The short pulse can be 2s or 5s, the standard pulse can be 10s, and the long pulse can be 30s. It can be set according to actual needs and is not specifically limited.

[0073] It should be understood that this embodiment sets multiple characteristic temperatures, multiple characteristic charge states and multiple characteristic pulse times. It is necessary to find the corresponding maximum pulse discharge current under different pulse times, different temperatures and different charge states to determine the pulse discharge capability of the battery cell, thereby determining the pulse discharge MAP of the battery cell and formulating the pulse discharge strategy of the battery cell.

[0074] Step S20, constructing a corresponding pulse discharge current optimization model based on the relationship between the cell operating voltage and the pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0075] It should be noted that according to the working principle of the battery, after the power is turned on, the working voltage of the battery cell during the pulse discharge process satisfies the following relationship:

[0076] V(t)=EI·DCR(t)

[0077] Wherein, V(t) represents the working voltage of the battery cell during pulse discharge, E represents the open circuit voltage of the battery cell at the initial moment of pulse discharge, that is, the open circuit voltage at the initial moment of discharge, I represents the pulse discharge current, and DCR(t) represents the dynamic internal resistance of the battery after the battery is connected to the load, that is, the dynamic internal resistance of the battery cell.

[0078] It can be seen that there is a linear functional relationship between the cell working voltage and the pulse discharge current in the form of y=-k·x+b. Therefore, in the variation curve of the cell working voltage and the pulse discharge current, as the pulse discharge current increases, the cell working voltage first has an inflection point, which does not satisfy the linear relationship. It is believed that the pulse discharge current corresponding to the cell working voltage at this time is the limit discharge current, which is recorded as I Limit The maximum pulse discharge current of lithium-ion batteries during pulse discharge is recorded as I max .

[0079] Therefore, this embodiment constructs a pulse discharge current optimization model based on the relationship between the battery cell operating voltage and the pulse discharge current, and the corresponding maximum pulse discharge current can be determined after solving the optimization model.

[0080] It is understandable that pulse time, temperature and state of charge affect the dynamic internal resistance of the battery cell, and temperature and state of charge affect the open circuit voltage of the battery cell. It can be seen that the dynamic internal resistance of the battery cell under different pulse times, different characteristic temperatures and different characteristic states of charge is different, and the open circuit voltage at the initial discharge moment under different characteristic temperatures and different characteristic states of charge is different. Therefore, under different characteristic pulse times, different characteristic temperatures, and different characteristic states of charge, different relationships between the working voltage of the battery cell and the pulse discharge current can be obtained, and corresponding pulse discharge current optimization models need to be constructed respectively.

[0081] It should be understood that in the process of determining the maximum pulse discharge current, in addition to satisfying the relationship between the battery cell operating voltage and the pulse discharge current, there are usually other requirements that need to be met. All requirements that need to be met can be set as constraints of the pulse discharge current optimization model, so that the maximum pulse discharge current obtained by solving can be reasonably applied.

[0082] In a feasible embodiment, the pulse discharge current optimization model includes at least the following constraints: the working voltage of the battery cell is equal to the open circuit voltage at the initial moment of discharge minus the product of the dynamic internal resistance of the battery cell and the pulse discharge current; the dynamic internal resistance of the battery cell is equal to the sum of the ohmic internal resistance and the polarization internal resistance; the dynamic internal resistance of the battery cell conforms to the internal resistance function relationship obtained by fitting; the working voltage of the battery cell at the end of discharge is greater than or equal to the discharge cut-off voltage; the pulse discharge current is greater than zero; the relationship between the working voltage of the battery cell and the pulse discharge current satisfies a linear relationship; the temperature rise of the battery cell after a single pulse is less than or equal to the preset temperature rise safety threshold.

[0083] It should be noted that the relationship between the cell operating voltage and the pulse discharge current can be described as follows: the cell operating voltage V(t) is equal to the open circuit voltage E at the initial moment of discharge minus the product of the cell dynamic internal resistance DCR(t) and the pulse discharge current I, that is, V(t) = EI·DCR(t). In this embodiment, the relationship between the cell operating voltage and the pulse discharge current needs to be able to approximately satisfy a linear relationship, which can be expressed as: Wherein, ∈ is a control constant, which can be set according to actual conditions and is generally a relatively small constant, and no specific limitation is given to this.

[0084] In addition, it should be noted that after the battery is connected to the load, the dynamic internal resistance DCR(t) of the battery cell includes the ohmic internal resistance R Ω and polarization internal resistance R f , which can be expressed as: DCR(t)=R Ω +R f . Ohm internal resistance R Ω It can be considered unchanged, the polarization internal resistance R f It changes dynamically. The pulse discharge process can affect the polarization internal resistance R f The factors mainly include: temperature, state of charge, pulse discharge current, discharge time (pulse time), etc. It can be seen that the dynamic internal resistance in this embodiment can be expressed as R f =f(T,SOC,I,t), where f(T,SOC,I,t) is the internal resistance function relationship, and the specific function form can be fitted according to the test data. Exemplarily, the dynamic current test method is used to perform a pulse discharge test on the battery cell. The specific test process is as follows: at different temperatures and different states of charge, different pulse discharge currents are used to perform pulse discharge tests, and the discharge time is equal to the set pulse time. The dynamic internal resistance of the battery cell corresponding to different pulse discharge currents is obtained, and the internal resistance function relationship is fitted using the test data. Using the internal resistance function relationship, the dynamic internal resistance of the battery cell under different characteristic pulse times, different characteristic temperatures, and different characteristic states of charge can be calculated.

[0085] It is understandable that the longer the discharge time, the smaller the cell working voltage. During the discharge process, it is necessary to ensure that the cell working voltage at the end of the pulse discharge is greater than or equal to the discharge cut-off voltage of the cell, that is, the cell working voltage V at the end of the discharge is greater than or equal to the discharge cut-off voltage V cut-off , which can be expressed as: V ≥ V cut-off , which can ensure that the cell operating voltage at other times during the discharge process must be greater than or equal to the discharge cut-off voltage. Since temperature and SOC value can affect the discharge cut-off voltage, it can be seen that the discharge cut-off voltage at different characteristic temperatures and different characteristic states of charge is different, and needs to be determined based on the characteristic temperature and characteristic state of charge used in the current test. In addition, the pulse discharge current needs to be greater than 0.

[0086] It should be understood that in order to ensure safety, the temperature rise ΔT of the single pulse cell needs to be less than or equal to the preset temperature rise safety threshold T saf , that is, ΔT≤T saf The single pulse cell temperature rise is the temperature rise of the cell under a single pulse. The preset temperature rise safety threshold is the set safety value of the temperature rise, for example: 5°C, which is set according to the actual situation and is not specifically limited.

[0087] In a feasible implementation manner, the step of calculating the temperature rise of a single pulse battery cell includes: obtaining the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, and obtaining a second corresponding relationship between the battery cell specific heat capacity, battery cell mass, pulse time, battery cell dynamic internal resistance, pulse discharge current and single pulse battery cell temperature rise; based on the second corresponding relationship, the battery cell specific heat capacity, battery cell mass and the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, determine the single pulse battery cell temperature rise corresponding to the pulse discharge current under different characteristic pulse times, different characteristic temperatures and different characteristic states of charge.

[0088] It should be noted that according to the law of conservation of energy, under adiabatic conditions, I 2 ·R·t=c p ·m·ΔT, the calculation relationship of the temperature rise of a single pulse battery cell can be obtained, that is, the second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the maximum pulse discharge current and the temperature rise of the single pulse battery cell, as shown below:

[0089]

[0090] In the formula, ΔT represents the temperature rise of the battery cell in a single pulse, c p represents the specific heat capacity of the battery cell, m represents the mass of the battery cell, t represents the pulse time, DCR(t) represents the dynamic internal resistance of the battery cell, and I represents the pulse discharge current.

[0091] It can be understood that the characteristic pulse time t m , characteristic temperature T k and characteristic state of charge SOC i Substitute the dynamic internal resistance of the battery cell, pulse discharge current, specific heat capacity of the battery cell, battery cell mass and pulse time into the above second corresponding relationship to obtain the characteristic pulse time t m , characteristic temperature T k and characteristic state of charge SOC i The single pulse cell temperature rise under different characteristic pulse times, different characteristic temperatures and pulse discharge currents under different characteristic charge states can be calculated.

[0092] Finally, the pulse discharge current optimization model can be described as:

[0093]

[0094] Where V(t) represents the working voltage of the battery during pulse discharge, E represents the open circuit voltage at the initial discharge moment, I represents the pulse discharge current, DCR(t) represents the dynamic internal resistance of the battery, and R Ω Represents the ohmic internal resistance, R f represents the polarization internal resistance, V represents the cell voltage at the end of discharge, V cut-off represents the discharge cut-off voltage, f(T,SOC,I,t) represents the internal resistance function relationship, ∈ is the control constant, T saf Indicates the preset temperature rise safety threshold, c p represents the specific heat capacity of the battery cell, m represents the mass of the battery cell, and t represents the pulse time.

[0095] Step S30, initializing the pulse discharge current of the chromosomes in the population and constructing a fitness function;

[0096] It should be noted that this embodiment solves the pulse discharge current optimization model based on an improved genetic algorithm.

[0097] It is understandable that when solving the problem, it is necessary to set relevant parameters and initialize the population. The parameters that need to be set usually include: population size, crossover rate, mutation rate, maximum number of iterations, etc., which are set according to actual conditions and are not specifically limited. The population is usually composed of multiple individuals, each of which is a chromosome, and each chromosome can carry a corresponding pulse discharge current value. A set of potential solutions is randomly generated as the initial value of the pulse discharge current of the chromosome in the population.

[0098] It should be understood that the fitness function is usually constructed according to the actual situation. The value of the pulse discharge current can be used as the fitness function, and other penalty terms or constraints can be added on this basis. There is no limitation on this. For example, the fitness function can be designed as:

[0099]

[0100] Where Fitness represents the fitness function, I represents the pulse discharge current, α and β represent the scaling factors, Linearity (I) is a metric between 0 and 1, V represents the cell voltage at the end of discharge, and V cut-off Indicates the discharge cut-off voltage.

[0101] Step S40, based on the fitness function, the chromosomes in the population are divided into elite individuals and non-elite individuals, and new individuals with new pulse discharge currents are generated based on the elite individuals and non-elite individuals, and the new individuals are combined with the elite individuals to generate a new population, and the iteration is continuously performed until the iteration termination condition is met to obtain the target population;

[0102] It should be noted that elite individuals refer to excellent chromosomes in the population, that is, excellent individuals, and non-elite individuals refer to chromosomes other than elite individuals in the population. New individuals are newly generated chromosomes, and new populations are composed of new individuals and elite individuals. Through continuous iteration, new populations are continuously formed until the iteration termination condition is met. At this time, the population obtained is the final required population, that is, the target population. The pulse discharge current of the chromosomes in the target population is the pulse discharge current that meets all the constraints of the pulse discharge current optimization model. The iteration termination condition can be reaching the maximum number of iterations or the fitness is no longer significantly improved, and there is no specific limitation.

[0103] It can be understood that this embodiment adopts an elite selection strategy to select a certain proportion of elite individuals from the population and directly copy them to the next generation to maintain the optimal solution of the population.

[0104] In a feasible implementation, based on the fitness function, the step of dividing the chromosomes in a population into elite individuals and non-elite individuals includes: calculating the fitness value of the chromosomes in the population based on the fitness function and the pulse discharge current of the chromosomes in the population; based on the fitness value of the chromosomes in the population, sorting the chromosomes in the population in descending order to obtain the individual sequence of the population; based on a preset elite ratio, determining the elite individuals in the individual sequence of the population; based on the elite individuals of the population, determining the non-elite individuals of the population.

[0105] It should be noted that, using the fitness function, the fitness value of each chromosome can be calculated, so that the chromosomes in the population can be sorted according to the fitness value. This embodiment adopts descending sorting, and the chromosomes are sorted from high to low according to the fitness value, and the individual sequence is the sequence after the chromosomes are sorted. The preset elite ratio is the ratio of selected elite individuals, for example: 10%, and the specific value can be flexibly adjusted according to actual needs, and no specific limitation is made to this.

[0106] It is understandable that when selecting elite individuals, individuals with higher fitness values ​​are usually selected, that is, individuals ranked at the top in the individual sequence are selected. For example, assuming that the preset elite ratio is e%, the top e% in the individual sequence are selected as the elite individuals of the population. After the elite individuals in the population are screened out, the remaining chromosomes are non-elite individuals.

[0107] It should be understood that there are usually two ways to generate new individuals, crossover operation and mutation operation.

[0108] In a feasible implementation, the steps of generating a new individual with a new pulse discharge current based on elite individuals and non-elite individuals include: generating a cross pulse discharge current based on the pulse discharge current of the elite individuals and the pulse discharge current of the non-elite individuals; perturbing the pulse discharge current of the non-elite individuals to determine the perturbed pulse discharge current; using the cross pulse discharge current and the perturbed pulse discharge current as new pulse discharge currents, and determining a new individual with a new pulse discharge current.

[0109] It should be noted that the cross-pulse discharge current is a new pulse discharge current obtained by the cross-operation. In this embodiment, a small random perturbation is performed on the pulse discharge current of the chromosome to increase the diversity of the introduced new individuals, and the new pulse discharge current obtained is the perturbed pulse discharge current. The cross-pulse discharge current and the perturbation pulse discharge current are combined to generate all the new pulse discharge currents, so that new individuals can be generated, and each new individual carries a new pulse discharge current.

[0110] In a feasible implementation, the step of generating a cross pulse discharge current based on the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual includes: cross-processing the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual based on the cross rate to obtain the cross pulse discharge current.

[0111] It can be understood that, in this embodiment, the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual are cross-operated at a preset cross-rate to generate corresponding cross-pulse discharge current.

[0112] In a feasible implementation manner, the pulse discharge current of a non-elite individual is disturbed, and the step of determining the disturbed pulse discharge current includes: determining a disturbed individual among the non-elite individuals based on a preset selection number; obtaining a first correspondence between the disturbance intensity, the scaling factor, the random value, the pulse discharge current and the disturbed pulse discharge current; and determining the disturbed pulse discharge current based on the disturbance intensity, the scaling factor, the random value, the pulse discharge current of the disturbed individual and the first correspondence.

[0113] It should be noted that the perturbation is performed on non-elite individuals. The perturbed individuals are the chromosomes that need to be perturbed among the non-elite individuals. Usually, a certain number of individuals are randomly selected for perturbation. The preset selection number is the preset number of selected perturbed individuals. The perturbed individuals are selected from the non-elite individuals according to the preset selection number.

[0114] It is understandable that a small random disturbance is required for the pulse discharge current of the disturbance individual. The first corresponding relationship between the disturbance intensity, the scaling factor, the random value, the pulse discharge current and the disturbance pulse discharge current, i.e., the calculation relationship of the disturbance pulse discharge current, is as follows:

[0115] I new =I+δ*rand()*I scale

[0116] In the formula, I new represents the disturbance pulse discharge current, δ represents the disturbance intensity, which is a decimal between 0 and 1 and is used to control the amplitude of the disturbance, I scale represents the scaling factor, which is used to ensure that the disturbance value matches the scale of the current value, rand() represents the random value, which is a random number uniformly distributed in the interval [-1,1], and I represents the pulse discharge current of the disturbance individual. Substitute the relevant values ​​into the above first corresponding relationship to calculate the disturbance pulse discharge current.

[0117] Step S50, taking the maximum value of the pulse discharge current of the chromosome in the target population as the solution of the corresponding pulse discharge current optimization model, and obtaining the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0118] It should be noted that the maximum value of the pulse discharge current of the chromosome in the target population is the maximum pulse discharge current, which is also the solution of the corresponding pulse discharge current optimization model, so that the maximum pulse discharge current under different characteristic pulse times, different characteristic temperatures, and different characteristic charge states can be determined in turn.

[0119] It can be seen that the cell has a characteristic pulse time t m and characteristic temperature T k The maximum pulse discharge current corresponding to different characteristic charge states is:

[0120]

[0121] Among them, T k represents the kth characteristic temperature, SOC i represents the i-th characteristic state of charge, Indicates that the cell is at characteristic temperature T k and characteristic state of charge SOC i The maximum discharge current under

[0122] Furthermore, we can get the cell’s characteristic pulse time t m The maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states is:

[0123]

[0124] In the formula, T1~T l Indicates characteristic temperature, SOC1~SOC j represents the characteristic state of charge, It indicates the maximum pulse discharge current of the battery cell at different characteristic temperatures and different characteristic charge states, I m (T,SOC) represents the characteristic pulse time t m Maximum pulse discharge current under different characteristic temperatures and different characteristic states of charge.

[0125] Step S60, determining the pulse discharge performance data of the battery cell based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0126] The pulse discharge performance data refers to the pulse discharge capability of the battery cell, which is usually characterized by the maximum pulse discharge current corresponding to different temperatures and different SOCs.

[0127] It can be understood that since the characteristic pulse time can be a long pulse, a standard pulse and a short pulse, the pulse discharge performance data of the battery cell under a long pulse can be obtained based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under the long pulse, and the pulse discharge performance data of the battery cell under a standard pulse can be obtained based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under the standard pulse. The pulse discharge performance data of the battery cell under a short pulse can be obtained based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under the short pulse.

[0128] It should be understood that the pulse discharge performance data of the battery cell under long pulse, the pulse discharge performance data of the battery cell under standard pulse and the pulse discharge performance data of the battery cell under short pulse are obtained as shown below:

[0129]

[0130] In the formula, I(T,SOC) represents the pulse discharge performance data, I Long (T,SOC) represents the pulse discharge performance data under long pulse, I stan (T,SOC) represents the pulse discharge performance data under standard pulse, I Short (T,SOC) represents the pulse discharge performance data under short pulse.

[0131] Step S70, evaluating and verifying the pulse discharge performance data, and formulating a pulse discharge MAP.

[0132] It should be noted that all the maximum pulse discharge currents obtained need to be further verified. After the verification is completed, the pulse discharge MAP is formulated and the pulse discharge strategy of the battery cell is formulated.

[0133] The present embodiment provides a method for evaluating the pulse discharge performance of a lithium-ion battery. The relationship between the operating voltage of a battery cell and the pulse discharge current is used to construct a pulse discharge current optimization model. By solving the model, the maximum pulse discharge current under different pulse times, different temperatures, and different states of charge is found, and the pulse discharge capability of the battery cell is quickly and accurately evaluated. At the same time, based on the pulse discharge capability of the battery cell, the pulse discharge MAP and pulse discharge strategy of the battery cell are formulated to ensure the safety of the battery cell throughout its life cycle and realize safe and efficient operation of the power battery.

[0134] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 2 , step S70 may include steps S701 to S703:

[0135] Step S701, setting a plurality of verification temperatures, a plurality of verification states of charge, and a plurality of verification pulse times;

[0136] It should be noted that the verification temperature is the temperature set for verification, such as: 25°C, 0°C, -20°C, usually selected from the characteristic temperature. The verification state of charge is the SOC value set for verification, such as: 10%, 50%, 90%, usually selected from the characteristic state of charge. The verification pulse time is the pulse time set for verification, such as: 2s, 10s, 30s, usually selected from the characteristic pulse time. Multiple verification temperatures, verification state of charge, and verification pulses can usually be set, and the specific values ​​and specific quantities can be set according to actual needs, and there is no specific limitation on this.

[0137] Step S702, based on the maximum pulse discharge current corresponding to different verification temperatures and different verification states of charge at each verification pulse time, a cyclic charge and discharge test is performed on the battery cell, and the state of the battery cell after the cyclic charge and discharge test is completed is determined;

[0138] It should be noted that, under the corresponding verification pulse time, verification temperature and verification charge state, the maximum pulse discharge current is used for discharge, with a duration of t1, followed by an interval of t2, and then the floating pulse discharge current is used for charging, with a duration of t3, followed by an interval of t4, to complete a charge and discharge test, a total of n cycles, thereby completing the cyclic charge and discharge test, and the number of cycles n can be flexibly adjusted according to actual needs.

[0139] It can be understood that the floating pulse discharge current = maximum pulse discharge current × pulse floating coefficient, and the pulse floating coefficient is set according to actual conditions and is not specifically limited.

[0140] It should be understood that the state of the battery cell includes the battery cell interface condition, battery cell lithium deposition condition and battery cell internal resistance change condition.

[0141] Step S703 , when the state of the battery cell meets the verification requirements, determine that the pulse discharge performance data of the battery cell is reasonable, and formulate a corresponding pulse discharge MAP and pulse discharge strategy.

[0142] It is understandable that after the cyclic charge and discharge test is completed, if the battery cell interface is good, there is no lithium deposition phenomenon and the battery cell internal resistance change is less than or equal to 10%, it means that the maximum pulse discharge current used in the cyclic charge and discharge test is reasonable, and thus the pulse discharge performance data of the battery cell can be considered reasonable, and the corresponding pulse discharge MAP and pulse discharge strategy can be formulated; otherwise, it means that the maximum pulse discharge current used in the cyclic charge and discharge test is unreasonable, and thus the pulse discharge performance data of the battery cell is unreasonable and needs to be recalculated.

[0143] The present embodiment provides a method for evaluating the pulse discharge performance of a lithium-ion battery. The relationship between the operating voltage of a battery cell and the pulse discharge current is used to construct a pulse discharge current optimization model. By solving the model, the maximum pulse discharge current under different pulse times, different temperatures, and different charge states is found, and all maximum pulse discharge currents are verified to ensure accuracy. The pulse discharge capability of the battery cell is evaluated quickly and accurately. At the same time, based on the pulse discharge capability of the battery cell, the pulse discharge MAP and pulse discharge strategy of the battery cell are formulated to ensure the safety of the battery cell throughout its life cycle and to achieve safe and efficient operation of the power battery.

[0144] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the evaluation method of the pulse discharge performance of the lithium-ion battery of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0145] This application also provides a device for evaluating the pulse discharge performance of a lithium-ion battery. Figure 3 , the evaluation device for the pulse discharge performance of lithium-ion batteries includes:

[0146] The parameter division module 10 is used to set a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, set a plurality of characteristic charge states within the charge state range, and set a plurality of characteristic pulse times;

[0147] The data calculation module 20 is used to construct a corresponding pulse discharge current optimization model based on the relationship between the cell operating voltage and the pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0148] The data calculation module 20 is also used to initialize the pulse discharge current of the chromosomes in the population and construct a fitness function;

[0149] The data calculation module 20 is also used to divide the chromosomes in the population into elite individuals and non-elite individuals based on the fitness function, and generate new individuals with new pulse discharge currents based on the elite individuals and non-elite individuals, combine the new individuals with the elite individuals to generate a new population, and continuously iterate until the iteration termination condition is met to obtain the target population;

[0150] The data calculation module 20 is also used to use the maximum value of the pulse discharge current of the chromosome in the target population as the solution of the corresponding pulse discharge current optimization model, and obtain the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0151] The data calculation module 20 is further used to determine the pulse discharge performance data of the battery cell based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time;

[0152] The evaluation and verification module 30 is used to evaluate and verify the pulse discharge performance data and formulate the pulse discharge MAP.

[0153] In a feasible implementation, the pulse discharge current optimization model includes at least the following constraints:

[0154] The working voltage of the battery cell is equal to the open circuit voltage at the initial moment of discharge minus the product of the dynamic internal resistance of the battery cell and the pulse discharge current;

[0155] The dynamic internal resistance of the battery cell is equal to the sum of the ohmic internal resistance and the polarization internal resistance;

[0156] The dynamic internal resistance of the battery cell conforms to the fitted internal resistance function relationship;

[0157] The working voltage of the battery cell at the end of discharge is greater than or equal to the discharge cut-off voltage;

[0158] The pulse discharge current is greater than zero;

[0159] The relationship between the cell operating voltage and pulse discharge current satisfies a linear relationship;

[0160] The temperature rise of the battery cell during a single pulse is less than or equal to the preset temperature rise safety threshold.

[0161] In a feasible implementation, the data calculation module 20 is further used to calculate the fitness value of the chromosomes in the population based on the fitness function and the pulse discharge current of the chromosomes in the population;

[0162] Based on the fitness values ​​of the chromosomes in the population, the chromosomes in the population are sorted in descending order to obtain the individual sequence of the population;

[0163] Based on the preset elite ratio, elite individuals are determined in the individual sequence of the population;

[0164] Based on the elite individuals of the population, determine the non-elite individuals of the population.

[0165] In a feasible implementation, the data calculation module 20 is further used to generate a cross pulse discharge current based on the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual;

[0166] The pulse discharge current of the non-elite individuals is disturbed to determine the disturbed pulse discharge current;

[0167] The cross pulse discharge current and the disturbance pulse discharge current are taken as new pulse discharge currents, and a new individual with the new pulse discharge current is determined.

[0168] In a feasible implementation manner, the data calculation module 20 is further used to perform cross processing on the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual based on the cross rate to obtain the cross pulse discharge current.

[0169] In a feasible implementation, the data calculation module 20 is further used to determine the disturbance individuals among the non-elite individuals based on a preset selection number;

[0170] Obtaining a first corresponding relationship between a disturbance intensity, a scaling factor, a random value, a pulse discharge current and a disturbance pulse discharge current;

[0171] The disturbance pulse discharge current is determined based on the disturbance intensity, the scaling factor, the random value, the pulse discharge current of the disturbance individual and the first corresponding relationship.

[0172] In a feasible implementation manner, the data calculation module 20 is further used to obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time;

[0173] Obtaining a second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the pulse discharge current and the temperature rise of the battery cell after a single pulse;

[0174] Based on the second corresponding relationship, the specific heat capacity of the battery cell, the battery cell mass, and the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, the single pulse battery cell temperature rise corresponding to the pulse discharge current under different characteristic pulse times, different characteristic temperatures and different characteristic states of charge is determined.

[0175] In a feasible implementation, the evaluation and verification module 30 is further used to set a plurality of verification temperatures, a plurality of verification states of charge, and a plurality of verification pulse times;

[0176] Based on the maximum pulse discharge current corresponding to different verification temperatures and different verification states of charge at each verification pulse time, the battery cell is subjected to a cyclic charge and discharge test, and the state of the battery cell after the cyclic charge and discharge test is completed is determined;

[0177] When the state of the battery cell meets the verification requirements, determine that the pulse discharge performance data of the battery cell is reasonable, and formulate corresponding pulse discharge MAP and pulse discharge strategy.

[0178] The device for evaluating the pulse discharge performance of lithium-ion batteries provided in the present application adopts the method for evaluating the pulse discharge performance of lithium-ion batteries in the above-mentioned embodiment, which can solve the technical problems that the traditional method for evaluating the pulse discharge performance of lithium-ion batteries is relatively complicated, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the device for evaluating the pulse discharge performance of lithium-ion batteries provided in the present application are the same as the beneficial effects of the method for evaluating the pulse discharge performance of lithium-ion batteries provided in the above-mentioned embodiment, and the other technical features of the device for evaluating the pulse discharge performance of lithium-ion batteries are the same as the features disclosed in the above-mentioned embodiment method, which will not be repeated here.

[0179] The present application provides a device for evaluating the pulse discharge performance of a lithium-ion battery, the device comprising: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for evaluating the pulse discharge performance of a lithium-ion battery in the first embodiment.

[0180] Reference below Figure 4, which shows a schematic diagram of the structure of a device for evaluating the pulse discharge performance of a lithium-ion battery suitable for implementing the embodiment of the present application. The device for evaluating the pulse discharge performance of a lithium-ion battery in the embodiment of the present application may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 4 The evaluation device for the pulse discharge performance of a lithium-ion battery shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0181] like Figure 4 As shown, the evaluation device for the pulse discharge performance of a lithium-ion battery may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the evaluation device for the pulse discharge performance of a lithium-ion battery are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow the evaluation device for the pulse discharge performance of a lithium-ion battery to communicate wirelessly or wired with other devices to exchange data. Although the figure shows an evaluation device for the pulse discharge performance of a lithium-ion battery with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have alternatively.

[0182] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0183] The lithium-ion battery pulse discharge performance evaluation device provided in the present application adopts the lithium-ion battery pulse discharge performance evaluation method in the above-mentioned embodiment, which can solve the technical problems that the traditional method of evaluating the lithium-ion battery pulse discharge performance is relatively complicated, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the lithium-ion battery pulse discharge performance evaluation device provided in the present application are the same as the beneficial effects of the lithium-ion battery pulse discharge performance evaluation method provided in the above-mentioned embodiment, and the other technical features of the lithium-ion battery pulse discharge performance evaluation device are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0184] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0185] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0186] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the method for evaluating the pulse discharge performance of a lithium-ion battery in the above-mentioned embodiment.

[0187] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0188] The computer-readable storage medium may be included in the device for evaluating the pulse discharge performance of a lithium-ion battery; or may exist independently without being assembled into the device for evaluating the pulse discharge performance of a lithium-ion battery.

[0189] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the lithium-ion battery pulse discharge performance evaluation device, the lithium-ion battery pulse discharge performance evaluation device: sets multiple characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, sets multiple characteristic charge states within the charge state range, and sets multiple characteristic pulse times; constructs a corresponding pulse discharge current optimization model based on the relationship between the battery cell operating voltage and the pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states under each characteristic pulse time; initializes the pulse discharge current of the chromosomes in the population and constructs a fitness function; and divides the chromosomes in the population into elite individuals based on the fitness function. The elite individuals and non-elite individuals are separated, and new individuals with new pulse discharge currents are generated based on the elite individuals and non-elite individuals. The new individuals are combined with the elite individuals to generate a new population, and the iteration is continuously performed until the iteration termination condition is met to obtain the target population; the maximum value of the pulse discharge current of the chromosomes in the target population is taken as the solution of the corresponding pulse discharge current optimization model, and the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time is obtained; based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at each characteristic pulse time, the pulse discharge performance data of the battery cell is determined; the pulse discharge performance data is evaluated and verified, and a pulse discharge MAP is formulated.

[0190] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0191] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0192] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0193] The readable storage medium provided in the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned lithium-ion battery pulse discharge performance evaluation method, which can solve the technical problems that the traditional method of evaluating the lithium-ion battery pulse discharge performance is relatively complex, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the present application are the same as the beneficial effects of the lithium-ion battery pulse discharge performance evaluation method provided in the above-mentioned embodiment, and will not be repeated here.

[0194] The present application also provides a computer program product, including a computer program, which implements the steps of the above-mentioned method for evaluating the pulse discharge performance of a lithium-ion battery when the computer program is executed by a processor.

[0195] The computer program product provided by the present application can solve the technical problem that the traditional method of evaluating the pulse discharge performance of lithium-ion batteries is relatively complicated, costly, and difficult to achieve quickly and accurately. Compared with the prior art, the beneficial effects of the computer program product provided by the present application are the same as the beneficial effects of the method for evaluating the pulse discharge performance of lithium-ion batteries provided by the above-mentioned embodiment, and will not be described in detail here.

[0196] The above are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for evaluating the pulse discharge performance of a lithium-ion battery, characterized in that: The method comprises: Setting a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, setting a plurality of characteristic charge states within the charge state range, and setting a plurality of characteristic pulse times; Based on the relationship between the cell operating voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time, a corresponding pulse discharge current optimization model is constructed; Initialize the pulse discharge current of chromosomes in the population and construct a fitness function; Based on the fitness function, the chromosomes in the population are divided into elite individuals and non-elite individuals, and new individuals with new pulse discharge currents are generated based on the elite individuals and the non-elite individuals, and the new individuals are combined with the elite individuals to generate a new population, and iterations are continuously performed until an iteration termination condition is met to obtain a target population; The maximum value of the pulse discharge current of the chromosome in the target population is taken as the solution of the corresponding pulse discharge current optimization model, and the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time is obtained; Determining pulse discharge performance data of the battery cell based on maximum pulse discharge currents corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; The pulse discharge performance data is evaluated and verified, and a pulse discharge MAP is developed.

2. The method according to claim 1, characterized in that The pulse discharge current optimization model includes at least the following constraints: The working voltage of the battery cell is equal to the open circuit voltage at the initial moment of discharge minus the product of the dynamic internal resistance of the battery cell and the pulse discharge current; The dynamic internal resistance of the battery cell is equal to the sum of the ohmic internal resistance and the polarization internal resistance; The dynamic internal resistance of the battery cell conforms to the fitted internal resistance function relationship; The working voltage of the battery cell at the end of discharge is greater than or equal to the discharge cut-off voltage; The pulse discharge current is greater than zero; The relationship between the cell operating voltage and pulse discharge current satisfies a linear relationship; The temperature rise of the battery cell during a single pulse is less than or equal to the preset temperature rise safety threshold.

3. The method according to claim 1, characterized in that The step of dividing the chromosomes in the population into elite individuals and non-elite individuals based on the fitness function comprises: Calculating the fitness value of the chromosomes in the population based on the fitness function and the pulse discharge current of the chromosomes in the population; Based on the fitness values ​​of the chromosomes in the population, the chromosomes in the population are sorted in descending order to obtain individual sequences of the population; Based on a preset elite ratio, determining elite individuals in the individual sequence of the population; Based on the elite individuals of the population, non-elite individuals of the population are determined.

4. The method according to claim 1, characterized in that The step of generating a new individual with a new pulse discharge current based on the elite individual and the non-elite individual comprises: generating a cross pulse discharge current based on the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual; perturbing the pulse discharge current of the non-elite individual to determine the perturbed pulse discharge current; The cross pulse discharge current and the disturbance pulse discharge current are taken as new pulse discharge currents, and a new individual with the new pulse discharge current is determined.

5. The method according to claim 4, characterized in that The step of generating a cross pulse discharge current based on the pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual comprises: The pulse discharge current of the elite individual and the pulse discharge current of the non-elite individual are cross-processed based on the cross-rate to obtain the cross-pulse discharge current.

6. The method according to claim 4, characterized in that The step of disturbing the pulse discharge current of the non-elite individual and determining the disturbed pulse discharge current comprises: Based on a preset number of selections, determining disturbance individuals among the non-elite individuals; Obtaining a first corresponding relationship between a disturbance intensity, a scaling factor, a random value, a pulse discharge current and a disturbance pulse discharge current; The disturbance pulse discharge current is determined based on the disturbance intensity, the scaling factor, the random value, the pulse discharge current of the disturbance individual and the first corresponding relationship.

7. The method according to claim 2, characterized in that The method further comprises: Obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time; Obtaining a second corresponding relationship between the specific heat capacity of the battery cell, the battery cell mass, the pulse time, the dynamic internal resistance of the battery cell, the pulse discharge current and the temperature rise of the battery cell after a single pulse; Based on the second corresponding relationship, the specific heat capacity of the battery cell, the battery cell mass, and the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, determine the single pulse battery cell temperature rise corresponding to the pulse discharge current under different characteristic pulse times, different characteristic temperatures and different characteristic states of charge.

8. The method according to any one of claims 1 to 7, characterized in that The steps of evaluating and verifying the pulse discharge performance data of the battery cell and formulating a corresponding pulse discharge MAP include: Set multiple verification temperatures, multiple verification states of charge, and multiple verification pulse times; Based on the maximum pulse discharge current corresponding to different verification temperatures and different verification states of charge at each verification pulse time, the battery cell is subjected to a cyclic charge and discharge test, and the state of the battery cell after the cyclic charge and discharge test is completed is determined; When the state of the battery cell meets the verification requirements, it is determined that the pulse discharge performance data of the battery cell is reasonable, and a corresponding pulse discharge MAP and pulse discharge strategy are formulated.

9. A device for evaluating the pulse discharge performance of a lithium-ion battery, characterized in that: The lithium-ion battery pulse discharge performance evaluation device comprises: A parameter division module, used to set a plurality of characteristic temperatures within the operating temperature range of the battery cell in the lithium-ion battery, set a plurality of characteristic charge states within the charge state range, and set a plurality of characteristic pulse times; A data calculation module is used to construct a corresponding pulse discharge current optimization model based on the relationship between the cell operating voltage and the pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states at each characteristic pulse time; The data calculation module is also used to initialize the pulse discharge current of the chromosomes in the population and construct a fitness function; The data calculation module is further used to divide the chromosomes in the population into elite individuals and non-elite individuals based on the fitness function, generate new individuals with new pulse discharge currents based on the elite individuals and the non-elite individuals, combine the new individuals with the elite individuals to generate a new population, and continuously iterate until the iteration termination condition is met to obtain a target population; The data calculation module is further used to use the maximum value of the pulse discharge current of the chromosome in the target population as the solution of the corresponding pulse discharge current optimization model, and obtain the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; The data calculation module is further used to determine the pulse discharge performance data of the battery cell based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic charge states of the battery cell at each characteristic pulse time; The evaluation and verification module is used to evaluate and verify the pulse discharge performance data and formulate a pulse discharge MAP.

10. A device for evaluating the pulse discharge performance of a lithium-ion battery, characterized in that: The device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the method for evaluating the pulse discharge performance of a lithium-ion battery according to any one of claims 1 to 8.

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