Lithium-ion battery pulse discharge performance evaluation method, device and equipment

Abstract

This application discloses a method, apparatus, and device for evaluating the pulse discharge performance of lithium-ion batteries, relating to the field of power battery technology. The method includes: constructing a corresponding pulse discharge current optimization model based on the relationship between the cell's operating voltage and pulse discharge current at different characteristic temperatures and states of charge under various characteristic pulse times; solving the pulse discharge current optimization model to obtain the maximum pulse discharge current of the cell at different characteristic temperatures and states of charge under various characteristic pulse times, thus determining the cell's pulse discharge performance data; evaluating and verifying the cell's pulse discharge performance data, and formulating a pulse discharge MAP. Through the above method, the maximum pulse discharge current of the cell at different pulse times, temperatures, and states of charge can be accurately determined, enabling rapid and accurate evaluation of the cell's pulse discharge capability and the formulation of the cell's pulse discharge MAP and pulse discharge strategy.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to methods, apparatus and equipment for evaluating the pulse discharge performance of lithium-ion batteries. Background Technology

[0002] The pulse discharge power of a lithium-ion battery characterizes the cell's short-term discharge capability. The magnitude 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 cell throughout its entire life cycle, thereby enabling the power battery to operate safely and efficiently.

[0003] In the existing technology, there are few studies on methods for rapidly 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 multiple test conditions, long test cycles, and high test resource and manpower costs.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

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

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

[0007] Multiple characteristic temperatures are set within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge are set within the state of charge range, and multiple characteristic pulse times are set.

[0008] Based on the relationship between the cell operating voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times, a corresponding pulse discharge current optimization model is constructed.

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

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

[0011] The maximum value of the pulse discharge current of chromosomes in the target population is used as the solution of the corresponding pulse discharge current optimization model to obtain the maximum pulse discharge current of the cell at different characteristic temperatures and different characteristic states of charge under each characteristic pulse time.

[0012] Based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times, the pulse discharge performance data of the battery cell is determined.

[0013] The pulse discharge performance data were evaluated and verified, and a pulse discharge MAP was developed.

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

[0015] The cell's operating voltage is equal to the open-circuit voltage at the initial moment of discharge minus the product of the cell's dynamic internal resistance and the pulse discharge current.

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

[0017] The dynamic internal resistance of the battery cell conforms to the internal resistance function relationship obtained by fitting.

[0018] The operating voltage of the cell at the discharge end is greater than or equal to the discharge cutoff voltage.

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

[0020] The relationship between the cell operating voltage and the pulse discharge current is linear.

[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, the step of dividing chromosomes in a population into elite and non-elite individuals based on a fitness function includes:

[0023] The fitness value of chromosomes in the population is calculated based on the fitness function and the pulse discharge current of chromosomes in the population.

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

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

[0026] Based on the elite individuals in the population, identify the non-elite individuals in the population.

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

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

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

[0030] The cross-pulse discharge current and the disturbance pulse discharge current are used as new pulse discharge currents, and new individuals with new pulse discharge currents are identified.

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

[0032] The pulse discharge current of elite individuals is cross-processed with the pulse discharge current of non-elite individuals based on the cross-rate to obtain the cross pulse discharge current.

[0033] In one embodiment, the step of perturbing the pulse discharge current of non-elite individuals and determining the perturbed pulse discharge current includes:

[0034] Based on a preset selection number, disturbed individuals are identified among non-elite individuals;

[0035] Obtain the first correspondence between disturbance intensity, scaling factor, random value, pulse discharge current and disturbance pulse discharge current;

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

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

[0038] Obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times;

[0039] Obtain the second correspondence between cell specific heat capacity, cell mass, pulse time, cell dynamic internal resistance, pulse discharge current and single pulse cell temperature rise;

[0040] Based on the second correspondence, the cell specific heat capacity, cell mass, and the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times, the single-pulse 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 developing a 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 states of charge at each verification pulse time, the cell is subjected to cyclic charge-discharge tests, and the state of the cell is determined after the cyclic charge-discharge tests are completed.

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

[0045] Furthermore, to achieve the above objectives, this application also proposes an evaluation device for the pulse discharge performance of lithium-ion batteries, the evaluation device comprising:

[0046] The parameter division module is used to set multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge within the state of charge range, and multiple characteristic pulse times.

[0047] The data calculation module is used to construct a corresponding pulse discharge current optimization model based on the relationship between the cell working voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under 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 chromosomes in the population into elite individuals and non-elite individuals based on the fitness function, and to generate new individuals with new pulse discharge currents based on the elite individuals and non-elite individuals. The new individuals are combined with elite individuals to generate a new population. The process is iterated 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 chromosomes in the target population as the solution of the corresponding pulse discharge current optimization model, and obtain the maximum pulse discharge current of the cell at different characteristic temperatures and different characteristic states of charge under 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 states of charge at various characteristic pulse times.

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

[0053] In addition, to achieve the above objectives, this application also proposes an evaluation device for the pulse discharge performance of a lithium-ion battery. The evaluation device for 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 evaluation method for the pulse discharge performance of a lithium-ion battery as described above.

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

[0055] In addition, to achieve the above objectives, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the method for evaluating the pulse discharge performance of a lithium-ion battery as described above.

[0056] This application provides a method for evaluating the pulse discharge performance of lithium-ion batteries. Multiple characteristic temperatures are set within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge are set within the state of charge range, and multiple characteristic pulse times are set. Based on the relationship between the cell operating voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, a corresponding pulse discharge current optimization model is constructed. The pulse discharge current of chromosomes in the population is initialized, and a fitness function is constructed. Based on the fitness function, chromosomes in the population are divided into elite individuals and non-elite individuals, and a model is generated based on the elite and non-elite individuals. New individuals with novel pulsed discharge currents are combined with elite individuals to generate a new population. This process is iterated until the iteration termination condition is met, resulting in the target population. The maximum pulsed discharge current of chromosomes in the target population is used as the solution to the corresponding pulsed discharge current optimization model, yielding the maximum pulsed discharge current of the battery cell at different characteristic temperatures and states of charge under various characteristic pulse times. Based on the maximum pulsed discharge current of the battery cell at different characteristic temperatures and states of charge under various characteristic pulse times, the pulsed discharge performance data of the battery cell is determined. The pulsed discharge performance data is evaluated and verified, and a pulsed discharge MAP is developed. This application utilizes the relationship between the cell's operating voltage 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, temperatures, and states of charge is found, enabling a rapid and accurate assessment of the cell's pulse discharge capability. Simultaneously, based on the cell's pulse discharge capability, a pulse discharge MAP and pulse discharge strategy are formulated to ensure the cell's safety throughout its entire life cycle, enabling the power battery to operate safely and efficiently. This solves the technical problems of traditional methods being complex, costly, and difficult to implement quickly and accurately when evaluating the pulse discharge performance of lithium-ion batteries. Attached Figure Description

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

[0058] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 This is a flowchart illustrating Example 1 of the method for evaluating the pulse discharge performance of lithium-ion batteries according to this application.

[0060] Figure 2This is a flowchart illustrating Example 2 of the method for evaluating the pulse discharge performance of lithium-ion batteries according to this application.

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

[0062] Figure 4 This is a schematic diagram of the hardware operating environment involved in the method for evaluating the pulse discharge performance of lithium-ion batteries in the embodiments of this application.

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

[0064] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0065] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

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

[0067] This application provides a method for evaluating the pulse discharge performance of lithium-ion batteries, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the method for evaluating the pulse discharge performance of lithium-ion batteries according to this 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: Set multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, set multiple characteristic states of charge within the state of charge range, and set multiple characteristic pulse times.

[0070] It should be noted that the operating temperature range of a battery cell typically refers to the temperature range within which the cell operates normally. This range can be set according to actual conditions and is not specifically limited. In this embodiment, the battery cell is a lithium-ion battery cell. The characteristic temperature refers to a pre-set operating temperature of the battery cell, used for subsequent testing. Multiple characteristic temperatures can usually be set, and the specific values ​​and number can be set according to actual needs; this is not specifically limited. For example, the set characteristic temperatures are 40℃, 25℃, 10℃, 0℃, -10℃, and -20℃.

[0071] Additionally, it should be noted that the state of charge range refers to the range of the cell's state of charge (SOC), typically from 0% to 100%. Characteristic state of charge refers to a pre-set SOC value for the cell, used for subsequent testing; multiple characteristic states of charge can usually be set. Characteristic states of charge can be selected by setting a SOC gradient. Based on the SOC gradient, a corresponding characteristic state of charge value is selected within the state of charge range. For example, if the set SOC gradient is ΔSOC, then the SOC... i = i·ΔSOC, where i is the i-th SOC value, SOC1 = 0 is the minimum SOC value of the cell, and SOC j =100% is the maximum SOC value of the battery cell, 0≤i≤j.

[0072] It is understandable that the characteristic pulse time refers to the preset pulse time, which is the duration of the pulse current. Multiple characteristic pulse times can usually 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. A short pulse can be 2s or 5s, a standard pulse can be 10s, and a long pulse can be 30s. These can be set according to actual needs, and there are no specific limitations.

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

[0074] Step S20: Based on the relationship between the cell operating voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, construct the corresponding pulse discharge current optimization model.

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

[0076] V(t)=EI·DCR(t)

[0077] In the formula, V(t) represents the cell working voltage during the pulse discharge process, E represents the cell open-circuit voltage at the initial moment of pulse discharge, i.e., 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, i.e., the dynamic internal resistance of the cell.

[0078] It is evident that the cell operating voltage and the pulse discharge current have a linear functional relationship of the form y = -k·x + b. Therefore, in the curve of the cell operating voltage versus the pulse discharge current, as the pulse discharge current increases, the cell operating voltage first reaches an inflection point, no longer satisfying the linear relationship. It is considered that the pulse discharge current corresponding to this cell operating voltage is the limiting discharge current, denoted as I. Limit The maximum pulse discharge current of a lithium-ion battery during pulse discharge is denoted as I. max .

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

[0080] It is understandable that pulse duration, temperature, and state of charge affect the dynamic internal resistance of the battery cell, while temperature and state of charge affect the open-circuit voltage. Therefore, the dynamic internal resistance of the battery cell differs with different pulse durations, characteristic temperatures, and characteristic states of charge, and the open-circuit voltage at the initial discharge moment differs with different characteristic temperatures and characteristic states of charge. Thus, different relationships between the battery cell's operating voltage and pulse discharge current can be obtained for different characteristic pulse durations, characteristic temperatures, and characteristic states of charge, requiring the construction of corresponding pulse discharge current optimization models.

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

[0082] In one feasible implementation, the pulse discharge current optimization model includes at least the following constraints: the cell operating voltage is equal to the open-circuit voltage at the initial discharge moment minus the product of the cell dynamic internal resistance and the pulse discharge current; the cell dynamic internal resistance is equal to the sum of the ohmic internal resistance and the polarization internal resistance; the cell dynamic internal resistance conforms to the fitted internal resistance function relationship; the cell operating voltage at the end of discharge is greater than or equal to the discharge cutoff voltage; the pulse discharge current is greater than zero; the relationship between the cell operating voltage and the pulse discharge current satisfies a linear relationship; and the cell temperature rise during a single pulse is less than or equal to a 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 discharge moment minus the product of the cell dynamic internal resistance DCR(t) and the pulse discharge current I, i.e., V(t) = EI·DCR(t). In this embodiment, the relationship between the cell operating voltage and the pulse discharge current needs to approximately satisfy a linear relationship, which can be expressed as: Wherein, ∈ is a control constant, which can be set according to the actual situation. It is generally a relatively small constant and is not specifically limited.

[0084] Additionally, it should be noted that after the battery is connected to a load, the dynamic internal resistance DCR(t) of the cell includes the ohmic internal resistance R. Ω and polarization internal resistance R f It can be expressed as: DCR(t) = R Ω +R f Ohmic internal resistance R Ω It can be assumed to remain unchanged, and the polarization internal resistance R f It is dynamically changing. The pulsed discharge process can affect the polarization resistance R. f The main factors include: temperature, state of charge, pulse discharge current, and discharge time (pulse time). Therefore, in this embodiment, the dynamic internal resistance can be expressed as R. f = f(T,SOC,I,t), where f(T,SOC,I,t) is the internal resistance function, the specific form of which can be obtained by fitting test data. For example, using the dynamic current testing method, pulse discharge tests are performed on the battery cell. The specific testing process is as follows: pulse discharge tests are conducted using different pulse discharge currents at different temperatures and under different states of charge. 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. Using the test data, the internal resistance function is fitted. Using the internal resistance function, the dynamic internal resistance of the battery cell under different characteristic pulse times, different characteristic temperatures, and different states of charge can be calculated.

[0085] Understandably, the longer the discharge time, the lower the cell's operating voltage. During the discharge process, it is necessary to ensure that the cell's operating voltage at the end of the pulse discharge is greater than or equal to the cell's discharge cutoff voltage, that is, the cell's operating voltage V at the end of the discharge is greater than or equal to the discharge cutoff voltage V. cut-off This can be expressed as: V≥V cut-off This ensures that the cell's operating voltage at other times during the discharge process is always greater than or equal to the discharge cutoff voltage. Since temperature and SOC (State of Charge) can affect the discharge cutoff voltage, it is evident that the discharge cutoff voltage differs at different characteristic temperatures and under different characteristic states of charge, and needs to be determined based on the characteristic temperature and characteristic state of charge used in the current test. Furthermore, the pulse discharge current needs to be greater than 0.

[0086] It should be understood that, to ensure safety, the temperature rise ΔT of a single pulsed cell must 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 refers to the temperature rise of the cell under a single pulse. The preset temperature rise safety threshold is a set safe value for the temperature rise, for example, 5℃. It is set according to the actual situation and there is no specific limitation on it.

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

[0088] It should be noted that, according to the law of conservation of energy, under adiabatic conditions, the following condition must be met: 2 ·R·t=c p From ·m·ΔT, we can obtain the calculation formula for the temperature rise of a single pulse cell, which is the second correspondence between the cell specific heat capacity, cell mass, pulse time, cell dynamic internal resistance, maximum pulse discharge current and the temperature rise of a single pulse cell, as shown below:

[0089]

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

[0091] It is understandable that the characteristic pulse time t m Characteristic temperature T k and characteristic state of charge (SOC) i Substituting the cell's dynamic internal resistance, pulse discharge current, cell specific heat capacity, cell mass, and pulse time into the second correspondence mentioned above, we obtain the characteristic pulse time t. m Characteristic temperature T k and characteristic state of charge (SOC) i The temperature rise of the cell under a single pulse is calculated, thereby determining the temperature rise of the cell under different characteristic pulse times, different characteristic temperatures, and different characteristic charge states corresponding to the pulse discharge current.

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

[0093]

[0094] In the formula, V(t) represents the cell operating voltage during the pulse discharge process, E represents the open-circuit voltage at the initial moment of discharge, I represents the pulse discharge current, DCR(t) represents the dynamic internal resistance of the cell, and R... Ω R represents the ohmic internal resistance. f V represents the polarization internal resistance, and V represents the cell voltage at the discharge end. cut-off Let f(T,SOC,I,t) represent the discharge cutoff voltage, f(T,SOC,I,t) represent the internal resistance function relationship, ∈ is the control constant, and T saf c represents the preset temperature rise safety threshold. 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: Initialize the pulse discharge current of chromosomes in the population and construct the fitness function;

[0096] It should be noted that this embodiment uses an improved genetic algorithm to solve the pulse discharge current optimization model.

[0097] Understandably, solving this problem requires setting relevant parameters and initializing the population. These parameters typically include population size, crossover rate, mutation rate, and maximum number of iterations, and are set according to the specific circumstances without specific limitations. The population usually consists of multiple individuals, each representing a chromosome, and each chromosome can carry a corresponding pulse discharge current value. A set of potential solutions is randomly generated as the initial values ​​for the pulse discharge currents of the chromosomes in the population.

[0098] It should be understood that the fitness function is usually constructed based on the actual situation. The value of the pulse discharge current can be used as the fitness function, or other penalty terms or constraints can be added on top of it; there are no restrictions on this. For example, the fitness function can be designed as follows:

[0099]

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

[0101] Step S40: Based on the fitness function, the chromosomes in the population are divided into elite individuals and non-elite individuals. New individuals with new pulse discharge currents are generated based on the elite individuals and non-elite individuals. The new individuals are combined with elite individuals to generate a new population. This process is repeated until the iteration termination condition is met to obtain the target population.

[0102] It should be noted that "elite individuals" refer to superior chromosomes within the population, while "non-elite individuals" are chromosomes other than elite individuals. New individuals are newly generated chromosomes, and a new population is formed by these new individuals and elite individuals. Through continuous iteration, new populations are continuously formed until the iteration termination condition is met. The resulting population is the final desired population, the target population. The pulse discharge current of the chromosomes in the target population is the pulse discharge current that satisfies all constraints of the pulse discharge current optimization model. The iteration termination condition can be reaching the maximum number of iterations or the fitness no longer significantly improving; no specific limitations are imposed.

[0103] It is understandable that this embodiment adopts an elite selection strategy, selecting a certain proportion of elite individuals from the population to directly replicate to the next generation, thus maintaining the optimal solution of the population.

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

[0105] It should be noted that the fitness function can be used to calculate the fitness value of each chromosome, allowing the chromosomes in the population to be sorted according to their fitness values. This embodiment uses descending order sorting, ranking the chromosomes from highest to lowest fitness value. The individual sequence is the sequence after the chromosomes are sorted. The preset elite ratio is the proportion of elite individuals selected, for example, 10%. The specific value can be flexibly adjusted according to actual needs and is not specifically limited.

[0106] Understandably, when selecting elite individuals, individuals with higher fitness values ​​are typically chosen, meaning those ranking higher in the individual sequence. For example, assuming a preset elite ratio of e%, the top e% of individuals in the sequence are selected as the elite individuals of the population. After selecting the elite individuals in the population, the remaining chromosomes are the non-elite individuals.

[0107] It should be understood that new individuals are usually generated in two ways: crossover and mutation.

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

[0109] It should be noted that the crossover pulse discharge current is the new pulse discharge current obtained through the crossover operation. In this embodiment, the pulse discharge current of the chromosome is subjected to a small random perturbation to enhance the diversity of the introduced new individuals, and the resulting new pulse discharge current is the perturbation pulse discharge current. The crossover pulse discharge current and the perturbation pulse discharge current are combined to generate all the new pulse discharge currents, thereby generating new individuals, each carrying a new pulse discharge current.

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

[0111] It is understood that in this embodiment, the pulse discharge current of elite individuals and the pulse discharge current of non-elite individuals are cross-operated at a pre-set cross rate to generate corresponding cross pulse discharge currents.

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

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

[0114] Understandably, a small random perturbation is needed to the pulse discharge current of the disturbed individual. The primary correspondence between the perturbation intensity, scaling factor, random value, pulse discharge current, and the perturbed pulse discharge current—that is, the formula for calculating the perturbed pulse discharge current—is as follows:

[0115] I new =I+δ*rand()*I scale

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

[0117] Step S50: The maximum value of the pulse discharge current of chromosomes in the target population is used as the solution of the corresponding pulse discharge current optimization model to obtain the maximum pulse discharge current of the cell at different characteristic temperatures and different characteristic states of charge under each characteristic pulse time.

[0118] It should be noted that the maximum value of the pulse discharge current of chromosomes in the target population is the maximum pulse discharge current, which is also the solution of the pulse discharge current optimization model. Thus, 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 at the characteristic pulse time t m and characteristic temperature T k The maximum pulse discharge current corresponding to different characteristic states of charge, i.e.:

[0120]

[0121] Among them, T k Represents the k-th characteristic temperature, SOC i Represents the i-th characteristic state of charge. This indicates the cell at its characteristic temperature T. k and characteristic state of charge (SOC) i The maximum discharge current.

[0122] Furthermore, the cell's characteristic pulse time t can be obtained. m The maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge, i.e.:

[0123]

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

[0125] Step S60: Based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge of the battery cell at various characteristic pulse times, determine the pulse discharge performance data of the battery cell.

[0126] Pulse discharge performance data refers to the pulse discharge capability of a battery cell, which is usually characterized by the maximum pulse discharge current corresponding to different temperatures and different states of charge (SOC).

[0127] Understandably, since the characteristic pulse duration can be long pulse, standard pulse, or short pulse, the pulse discharge performance data of the battery cell under long pulse can be obtained based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under long pulse. Similarly, the pulse discharge performance data of the battery cell under standard pulse can be obtained based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under standard pulse. Finally, the pulse discharge performance data of the battery cell under short pulse can be obtained based on the maximum pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under short pulse.

[0128] It should be understood that the pulse discharge performance data of the battery cell is obtained based on the pulse discharge performance data of the battery cell under long pulses, the pulse discharge performance data of the battery cell under standard pulses, and the pulse discharge performance data of the battery cell under short pulses, 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 conditions, I stan (T,SOC) represents the pulse discharge performance data under standard pulse conditions, I Short (T,SOC) represents the pulse discharge performance data under short pulse conditions.

[0131] Step S70: Evaluate and verify the pulse discharge performance data, and develop a pulse discharge MAP.

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

[0133] This embodiment provides a method for evaluating the pulse discharge performance of lithium-ion batteries. By utilizing the relationship between the cell's operating voltage and the pulse discharge current, a pulse discharge current optimization model is constructed. By solving the model, the maximum pulse discharge current under different pulse times, temperatures, and states of charge is found, allowing for a rapid and accurate evaluation of the cell's pulse discharge capability. Simultaneously, based on the cell's pulse discharge capability, a pulse discharge MAP and pulse discharge strategy are formulated to ensure the cell's safety throughout its entire life cycle and achieve safe and efficient operation of the power battery.

[0134] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in the first embodiment described above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 2 Step S70 may include steps S701 to S703:

[0135] Step S701: Set multiple verification temperatures, multiple verification states of charge, and multiple verification pulse times;

[0136] It should be noted that the verification temperature is the set temperature used for verification, such as 25℃, 0℃, or -20℃, usually selected from the characteristic temperatures. The verification state of charge (SOC) is the set SOC value used for verification, such as 10%, 50%, or 90%, usually selected from the characteristic SOC. The verification pulse duration is the set pulse duration used for verification, such as 2s, 10s, or 30s, usually selected from the characteristic pulse duration. Multiple verification temperatures, verification SOCs, and verification pulses can usually be set; the specific values ​​and number can be set according to actual needs and are not specifically limited.

[0137] Step S702: Based on the maximum pulse discharge current corresponding to different verification temperatures and different states of charge at each verification pulse time, perform cyclic charge-discharge tests on the cell and determine the state of the cell after the cyclic charge-discharge test is completed.

[0138] It should be noted that, under the corresponding verification pulse time, verification temperature, and verification state of charge, 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 one charge-discharge test. The test is repeated n times in total to complete the cyclic charge-discharge test. The number of cycles n can be flexibly adjusted according to actual needs.

[0139] It is understandable that the downward pulse discharge current = maximum pulse discharge current × pulse downward coefficient. The pulse downward coefficient is set according to the actual situation and is not specifically limited.

[0140] It should be understood that the state of a battery cell includes the cell interface condition, lithium plating condition, and changes in internal resistance.

[0141] Step S703: When the cell's condition meets the verification requirements, determine that the cell's pulse discharge performance data is reasonable, and formulate the corresponding pulse discharge MAP and pulse discharge strategy.

[0142] Understandably, after the cyclic charge-discharge test is completed, if the cell interface is good, there is no lithium plating, and the change in cell internal resistance is less than or equal to 10%, it indicates that the maximum pulse discharge current used in the cyclic charge-discharge test is reasonable. Therefore, the pulse discharge performance data of the cell can be considered reasonable, and the corresponding pulse discharge MAP and pulse discharge strategy can be formulated. Otherwise, it indicates that the maximum pulse discharge current used in the cyclic charge-discharge test is unreasonable, and the pulse discharge performance data of the cell can be considered unreasonable, requiring recalculation.

[0143] This embodiment provides a method for evaluating the pulse discharge performance of lithium-ion batteries. By utilizing the relationship between the cell's operating voltage and the pulse discharge current, a pulse discharge current optimization model is constructed. By solving the model, the maximum pulse discharge current under different pulse times, temperatures, and states of charge is found. All maximum pulse discharge currents are verified to ensure accuracy. This method quickly and accurately evaluates the cell's pulse discharge capability. Simultaneously, based on the cell's pulse discharge capability, a pulse discharge MAP and pulse discharge strategy are formulated to ensure the cell's safety throughout its entire life cycle and achieve safe and efficient operation of the power battery.

[0144] It should be noted that the above examples are only for understanding this application and do not constitute a limitation on the evaluation method of the pulse discharge performance of lithium-ion batteries in this application. Any simple modifications based on this technical concept are within the protection scope of this application.

[0145] This application also provides an evaluation device for the pulse discharge performance of lithium-ion batteries, please refer to... 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 multiple characteristic temperatures within the operating temperature range of the cell in a lithium-ion battery, multiple characteristic states of charge within the state of charge range, and multiple characteristic pulse times.

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

[0148] The data calculation module 20 is also used to initialize the pulse discharge current of chromosomes in the population and construct the 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 to generate new individuals with new pulse discharge currents based on the elite individuals and non-elite individuals. The new individuals are combined with elite individuals to generate a new population. The process is iterated until the iteration termination condition is met to obtain the target population.

[0150] The data calculation module 20 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 of the cell at different characteristic temperatures and different characteristic states of charge under each characteristic pulse time.

[0151] The data calculation module 20 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 states of charge of the battery cell at various characteristic pulse times.

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

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

[0154] The cell's operating voltage is equal to the open-circuit voltage at the initial moment of discharge minus the product of the cell's dynamic internal resistance and the pulse discharge current.

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

[0156] The dynamic internal resistance of the battery cell conforms to the internal resistance function relationship obtained by fitting.

[0157] The operating voltage of the cell at the discharge end is greater than or equal to the discharge cutoff voltage.

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

[0159] The relationship between the cell operating voltage and the pulse discharge current is linear.

[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 one feasible implementation, the data calculation module 20 is also used to calculate the fitness value of chromosomes in the population based on the fitness function and the pulse discharge current of chromosomes in the population.

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

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

[0164] Based on the elite individuals in the population, identify the non-elite individuals in the population.

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

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

[0167] The cross-pulse discharge current and the disturbance pulse discharge current are used as new pulse discharge currents, and new individuals with new pulse discharge currents are identified.

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

[0169] In one feasible implementation, the data calculation module 20 is also used to identify disturbed individuals among non-elite individuals based on a preset selection number;

[0170] Obtain the first correspondence between disturbance intensity, scaling factor, random value, pulse discharge current and disturbance pulse discharge current;

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

[0172] In one feasible implementation, the data calculation module 20 is also used to obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time.

[0173] Obtain the second correspondence between cell specific heat capacity, cell mass, pulse time, cell dynamic internal resistance, pulse discharge current and single pulse cell temperature rise;

[0174] Based on the second correspondence, the cell specific heat capacity, cell mass, and the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times, the single-pulse 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 one feasible implementation, the evaluation and verification module 30 is also used to set multiple verification temperatures, multiple verification states of charge, and multiple verification pulse times.

[0176] Based on the maximum pulse discharge current corresponding to different verification temperatures and different states of charge at each verification pulse time, the cell is subjected to cyclic charge-discharge tests, and the state of the cell is determined after the cyclic charge-discharge tests are completed.

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

[0178] The lithium-ion battery pulse discharge performance evaluation device provided in this application adopts the lithium-ion battery pulse discharge performance evaluation method in the above embodiments, which can solve the technical problems that traditional methods for evaluating the pulse discharge performance of lithium-ion batteries are relatively complex, 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 this application are the same as those of the lithium-ion battery pulse discharge performance evaluation method provided in the above embodiments, and other technical features in the lithium-ion battery pulse discharge performance evaluation device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0179] This application provides an evaluation device for the pulse discharge performance of a lithium-ion battery. The evaluation device for the pulse discharge performance of a lithium-ion battery includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the evaluation method for the pulse discharge performance of a lithium-ion battery in the above embodiment 1.

[0180] The following is for reference. Figure 4This document illustrates a schematic diagram of a structure suitable for evaluating the pulse discharge performance of lithium-ion batteries in accordance with embodiments of this application. The evaluation device for the pulse discharge performance of lithium-ion batteries in embodiments of this application may include, but is not limited to, mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Description), PMPs (Portable Media Players), and in-vehicle terminals (e.g., in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 4 The lithium-ion battery pulse discharge performance evaluation device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0181] like Figure 4 As shown, the lithium-ion battery pulse discharge performance evaluation device may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 into a random access memory (RAM) 1004. The RAM 1004 also stores various programs and data required for the operation of the lithium-ion battery pulse discharge performance evaluation device. The processing unit 1001, ROM 1002, and RAM 1004 are interconnected 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 I / O interface 1006: input devices 1007 including, for example, touchscreens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 1008 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 1003 including, for example, magnetic tapes, hard disks, etc.; and communication devices 1009. Communication device 1009 allows the lithium-ion battery pulse discharge performance evaluation device to communicate wirelessly or wiredly with other devices to exchange data. Although the figure shows a lithium-ion battery pulse discharge performance evaluation device with various systems, it should be understood that it is not required to implement or possess all the systems shown. More or fewer systems can be implemented alternatively.

[0182] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from ROM 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0183] The lithium-ion battery pulse discharge performance evaluation device provided in this application, employing the lithium-ion battery pulse discharge performance evaluation method described in the above embodiments, solves the technical problems of traditional methods being complex, costly, and difficult to implement quickly and accurately when evaluating the pulse discharge performance of lithium-ion batteries. Compared with the prior art, the beneficial effects of the lithium-ion battery pulse discharge performance evaluation device provided in this application are the same as those of the lithium-ion battery pulse discharge performance evaluation method provided in the above embodiments, and other technical features of this lithium-ion battery pulse discharge performance evaluation device are the same as those disclosed in the method of the previous embodiment, and will not be repeated here.

[0184] It should be understood that the various parts disclosed in this application can be implemented using 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 suitable manner in one or more embodiments or examples.

[0185] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0186] This application provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to execute the lithium-ion battery pulse discharge performance evaluation method in the above embodiments.

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

[0188] The aforementioned computer-readable storage medium may be included in an evaluation device for the pulse discharge performance of lithium-ion batteries; or it may exist independently and not assembled into an evaluation device for the pulse discharge performance of lithium-ion batteries.

[0189] The aforementioned computer-readable storage medium carries one or more programs. When these programs are executed by the lithium-ion battery pulse discharge performance evaluation device, the evaluation device performs the following: It sets multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge within the state of charge range, and multiple characteristic pulse times; based on the relationship between the cell operating voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time, it constructs a corresponding pulse discharge current optimization model; it initializes the pulse discharge current of chromosomes in the population and constructs a fitness function; based on the fitness function, it divides the chromosomes in the population into elite individuals. The system iterates between elite and non-elite individuals, generating new individuals with novel pulsed discharge currents based on these combinations. These new individuals are then combined with elite individuals to create a new population. This process continues iteratively until the iteration termination condition is met, yielding the target population. The maximum pulsed discharge current of chromosomes within the target population is used as the solution to the corresponding pulsed discharge current optimization model, obtaining the maximum pulsed discharge current corresponding to different characteristic temperatures and states of charge at various characteristic pulse times. Based on the maximum pulsed discharge current corresponding to different characteristic temperatures and states of charge at various characteristic pulse times, the pulsed discharge performance data of the battery cell is determined. The pulsed discharge performance data is then evaluated and verified, and a pulsed discharge MAP is established.

[0190] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0191] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0192] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0193] The readable storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described method for evaluating the pulse discharge performance of lithium-ion batteries. This solves the technical problems that traditional methods for evaluating the pulse discharge performance of lithium-ion batteries are complex, costly, and difficult to implement quickly and accurately. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the lithium-ion battery pulse discharge performance evaluation method provided in the above embodiments, and will not be repeated here.

[0194] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method for evaluating the pulse discharge performance of a lithium-ion battery as described above.

[0195] The computer program product provided in this application can solve the technical problems that traditional methods for evaluating the pulse discharge performance of lithium-ion batteries are complex, costly, and difficult to implement quickly and accurately. Compared with the prior art, the beneficial effects of the computer program product provided in this application are the same as those of the lithium-ion battery pulse discharge performance evaluation method provided in the above embodiments, and will not be repeated here.

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

Claims

1. A method for evaluating the pulse discharge performance of a lithium-ion battery, characterized in that, The method includes: Multiple characteristic temperatures are set within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge are set within the state of charge range, and multiple characteristic pulse times are set. Based on the relationship between the cell operating voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times, a corresponding pulse discharge current optimization model is constructed. Initialize the pulsed discharge current of chromosomes in the population and construct the fitness function; Based on the fitness function, the chromosomes in the population are divided into elite individuals and non-elite individuals. 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. This process is repeated 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 of the battery cell at different characteristic temperatures and different characteristic states of charge under 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 various characteristic pulse times, the pulse discharge performance data of the battery cell is determined. The pulse discharge performance data were evaluated and verified, and a pulse discharge MAP was developed.

2. The method as described in claim 1, characterized in that, The pulse discharge current optimization model includes at least the following constraints: The cell's operating voltage is equal to the open-circuit voltage at the initial moment of discharge minus the product of the cell's dynamic internal resistance and the pulse discharge current. The dynamic internal resistance of a battery cell is equal to the sum of its ohmic internal resistance and polarization internal resistance. The dynamic internal resistance of the battery cell conforms to the internal resistance function relationship obtained by fitting. The operating voltage of the cell at the discharge end is greater than or equal to the discharge cutoff voltage. The pulse discharge current is greater than zero; The relationship between the cell operating voltage and the pulse discharge current is linear. 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 as described in claim 1, characterized in that, The step of dividing chromosomes in the population into elite individuals and non-elite individuals based on the fitness function includes: The fitness value of the chromosomes in the population is calculated based on the fitness function and the pulse discharge current of the chromosomes in the population. Based on the fitness values ​​of chromosomes in the population, the chromosomes in the population are sorted in descending order to obtain the individual sequences of the population; Based on a preset elite ratio, elite individuals are identified in the individual sequence of the population. Based on the elite individuals of the population, the non-elite individuals of the population are determined.

4. The method as described in claim 1, characterized in that, The step of generating a new individual with a new pulsed discharge current based on the elite individual and the non-elite individual includes: A cross-pulse discharge current is generated based on the pulse discharge current of the elite individuals and the pulse discharge current of the non-elite individuals. The pulse discharge current of the non-elite individuals is perturbed to determine the perturbed pulse discharge current; The cross pulse discharge current and the disturbance pulse discharge current are used as new pulse discharge currents, and a new individual with the new pulse discharge current is determined.

5. The method as described in 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 includes: 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 as described in claim 4, characterized in that, The step of perturbing the pulse discharge current of the non-elite individuals and determining the perturbed pulse discharge current includes: Based on a preset selection number, disturbing individuals are identified among the non-elite individuals; Obtain the first correspondence between disturbance intensity, scaling factor, random value, pulse discharge current and disturbance pulse discharge current; The perturbation pulse discharge current is determined based on the perturbation intensity, scaling factor, random value, pulse discharge current of the perturbation individual, and the first correspondence.

7. The method as described in claim 2, characterized in that, The method further includes: Obtain the dynamic internal resistance of the battery cell corresponding to different characteristic temperatures and different characteristic states of charge under various characteristic pulse times; Obtain the second correspondence between cell specific heat capacity, cell mass, pulse time, cell dynamic internal resistance, pulse discharge current and single pulse cell temperature rise; Based on the second correspondence, the cell specific heat capacity, cell mass, and the cell dynamic internal resistance corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time, the single pulse 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.

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 developing the 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 states of charge at each verification pulse time, the cell is subjected to cyclic charge-discharge tests, and the state of the cell is determined after the cyclic charge-discharge tests are completed. When the cell's condition meets the verification requirements, the cell's pulse discharge performance data is determined to be reasonable, and 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 device for evaluating the pulse discharge performance of lithium-ion batteries includes: The parameter division module is used to set multiple characteristic temperatures within the operating temperature range of the lithium-ion battery cell, multiple characteristic states of charge within the state of charge range, and multiple characteristic pulse times. The data calculation module is used to construct a corresponding pulse discharge current optimization model based on the relationship between the cell working voltage and pulse discharge current corresponding to different characteristic temperatures and different characteristic states of charge under each characteristic pulse time. The data calculation module is also used to initialize the pulse discharge current of chromosomes in the population and construct the fitness function; 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, 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. 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 of the cell corresponding to different characteristic temperatures and different characteristic states of charge at each characteristic pulse time. 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 states of charge 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 to develop a pulse discharge MAP.

10. An evaluation device for the pulse discharge performance of lithium-ion batteries, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the method for evaluating the pulse discharge performance of a lithium-ion battery as described in any one of claims 1 to 8.

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