Battery Peak Power Fitting Test Method and System

Abstract

This invention discloses a method and system for testing peak power fitting of batteries, relating to the field of battery optimization technology. It includes: obtaining peak discharge power data of batteries at different temperatures and states of charge (SOCs) through experiments; calculating the DC internal resistance values ​​at different SOCs based on the peak discharge power data; fitting different SOCs with their corresponding DC internal resistance values ​​to obtain the fitting relationship between DC internal resistance values ​​and SOCs at different temperatures and SOCs; and fitting the actual peak power values ​​with the DC internal resistance values ​​to obtain the fitting relationship between the actual peak power values ​​and DC internal resistance values ​​at different temperatures, thereby obtaining the fitting relationship between the actual peak power values ​​and SOCs at different temperatures and SOCs. This invention can quickly and accurately obtain the peak discharge power of lithium-ion batteries at different SOCs in different environments.

Description

Technical Field

[0001] This invention belongs to the field of battery optimization technology, specifically a battery peak power fitting test method and system. Background Technology

[0002] With the increasing severity of energy and environmental issues, new energy vehicles have become a key development direction for many countries. Lithium-ion batteries, due to their high energy density and low cost, are widely used in electric vehicles. The state of power (SOP) of a battery represents its maximum input and output power under different conditions, indicating its ability to withstand charging and discharging power. Peak power is a crucial performance indicator for electric vehicles. During vehicle operation, acceleration and hill climbing should be performed according to the SOP strategy defined by the Battery Management System (BMS) to optimize battery usage, avoid overcharging or over-discharging, extend battery life, and achieve optimal battery performance. However, measuring the peak power of a battery system experimentally is time-consuming, labor-intensive, and requires sophisticated testing equipment. Therefore, estimating the peak power of a battery system using appropriate methods is of great significance.

[0003] The inventors discovered that there are many methods for predicting peak power, such as:

[0004] The publication CN112068000B, entitled "A Method for Predicting Peak Power Considering the Impact of Power Battery Durability," discloses a method that, compared to existing technologies, adds constraints on the rate of temperature change and aging to the existing constraints, in addition to the highest battery temperature. Since the rate of temperature change effectively reflects battery health changes at any ambient temperature, this invention better reflects changes in battery health, reduces capacity loss, and improves durability. Furthermore, considering the impact of current rate on battery capacity degradation, this invention derives the relationship between current rate and capacity degradation constraints from a capacity loss model. Using the capacity degradation limit as a constraint, it predicts the peak current during continuous charging and discharging, thereby enabling prediction of peak power during continuous charging and discharging, which is of significant importance for battery durability.

[0005] Announcement No. CN108363009B, entitled "A Method for Online Prediction of Maximum Allowable Power of Lithium-ion Batteries," discloses the following method: Based on the charging and discharging characteristics of lithium-ion batteries, a battery physical model is established, and the battery's state of charge (SOC) and polarization voltage are calculated. Using the battery physical model, with SOC and polarization voltage as initial conditions and the battery's maximum allowable transient charging and discharging current as the initial trial current, the difference between the battery terminal voltage and the battery's charge / discharge limit voltage is calculated. Based on this difference, the increment of the trial current is adjusted to obtain a new trial current. The battery physical model iteratively calculates the battery terminal voltage until the conditions for calculating the maximum allowable charge / discharge power under the current operating state are met, thus achieving online real-time prediction of the maximum power state of lithium-ion batteries. This invention overcomes the problem that the estimation of maximum allowable charge / discharge power is constrained by the coupling of factors such as operating conditions, temperature, SOC, and degradation, ensuring the estimation accuracy.

[0006] For example, CN 114545257A, entitled "A Method, Electronic Device, and Medium for Obtaining a Lithium-ion Battery Power Meter," discloses: obtaining the magnitude of the pulse current of a lithium-ion battery at multiple temperatures corresponding to an initial duration and initial state of charge (SOC); calculating the magnitude of the pulse current of the lithium-ion battery at different durations under the initial duration and initial SOC; calculating the depth of charge / discharge of the lithium-ion battery at the initial temperature, initial SOC, and initial duration; calculating the proportional gain; obtaining the magnitude of the pulse current of the lithium-ion battery at different durations under the initial SOC and initial temperature; calculating the magnitude of the pulse current of the lithium-ion battery at different temperatures and different durations under the initial SOC; calculating the magnitude of the pulse current of the lithium-ion battery at all SOCs, all temperatures, and all durations; and then plotting a lithium-ion battery power meter. Compared with existing technologies, this invention can save a significant amount of testing time and resources, and has higher accuracy.

[0007] However, these methods have long evaluation cycles, use many parameters, and produce complex models that are difficult to implement. Furthermore, all of these methods neglect the impact of DC internal resistance on battery power; the internal resistance of a battery varies under different states of charge (SOC). In particular, DC internal resistance directly affects the battery's power performance and reflects its performance in actual use. Summary of the Invention

[0008] The purpose of this invention is to provide a battery peak power fitting test method and system. Based on DC internal resistance fitting, it innovatively proposes a new lithium-ion battery peak power prediction model to predict the battery peak power. This model can quickly and accurately obtain the peak discharge power of lithium-ion batteries under different environments and SOCs, which is more conducive to the rational optimization of battery use.

[0009] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0010] The first aspect of this invention provides a method for testing battery peak power fitting.

[0011] The battery peak power fitting test method includes the following steps:

[0012] The peak discharge power data of the battery under different temperatures and different states of charge (SOC) were obtained through experiments, including open circuit voltage, terminal voltage and peak current value.

[0013] Based on the open-circuit voltage, terminal voltage, and peak current value, calculate the DC internal resistance value under different states of charge (SOC).

[0014] By fitting different states of charge (SOC) with their corresponding DC internal resistance values, the fitting relationship between DC internal resistance and SOC under different temperatures and different SOC values ​​is obtained.

[0015] The true peak power value is calculated, and then fitted with the DC internal resistance value again to obtain the fitting relationship between the true peak power value and the DC internal resistance value at different temperatures. In turn, the fitting relationship between the true peak power value and the state of charge (SOC) under different temperatures and different SOC values ​​is obtained, thus realizing the fitting test of the battery peak power.

[0016] As an alternative technical solution, peak battery discharge power data is obtained through experimental methods, specifically including:

[0017] Step 1: Select a batch of lithium batteries of the same capacity and discharge them at a constant current rate to the first set voltage value.

[0018] Step 2: Starting from the first set voltage value, perform constant current and constant voltage charging until the second set voltage value is reached;

[0019] Step 3: Starting from the second set voltage value, discharge at a set rate with constant current for different durations to bring the batch of lithium batteries to different states of charge (SOC).

[0020] Step 4: Place batches of lithium batteries with different states of charge (SOC) at different temperatures and record the open-circuit voltage of the lithium batteries.

[0021] Step 5: Set the constant current discharge time to the first set voltage value based on the reference value;

[0022] Step 6: Repeat steps 2 to 5 above. In step 5, based on the baseline value, increase or decrease the current by the set value each time to find the peak current. Record the terminal voltage and the peak current value that meets the standard during the process.

[0023] As an alternative technical solution, the method for calculating the DC internal resistance value is as follows:

[0024] DCR = (V0 - V1) / I * 1000;

[0025] Where V0 is the open-circuit voltage; V1 is the terminal voltage; I is the peak current value; and DCR is the DC internal resistance value.

[0026] As an alternative technical solution, the fitting relationship between the DC internal resistance and the state of charge (SOC) at different temperatures and under different SOCs is as follows:

[0027] At 25℃, 90% SOC - 20% SOC:

[0028] y1=0.8111x 2 -1.7768x + 1.8599;

[0029] At 25℃, 20% SOC - 5% SOC:

[0030] y2=20.932x 2 -13.256x + 3.3538;

[0031] At 45℃, 90% SOC - 30% SOC:

[0032] y3 = 0.5104x 2 -1.0554x + 1.2979;

[0033] At 45℃, 30% SOC - 5% SOC:

[0034] y4 = 15.397x 2 -8.7931x+2.2736;

[0035] At 0℃, 90% SOC - 30% SOC:

[0036] y5 = -7.726x 3 +18.099x 2 -15.074x + 6.23;

[0037] At 0℃, 30% SOC - 5% SOC:

[0038] y6 = 10.075x 2 The function expression for -4.5597x + 4.6651;

[0039] Where x represents the variable state of charge (SOC) and y represents the DC internal resistance (DCR).

[0040] As an alternative technical solution, the specific method for calculating the actual peak power value is as follows:

[0041] P1 = I * V1

[0042] Where P1 is the actual peak power; V1 is the terminal voltage; and I is the target peak current value.

[0043] As an alternative technical solution, the fitting relationship between the actual peak power value and the DC internal resistance value at different temperatures is as follows:

[0044] At 25℃: F(y)=-311.18y 3 +2248.3y 2 -5727.7y+5854;

[0045] At 45℃: F(y)=-1628.6y 3 +7739.2y 2 -13144y+8978.1;

[0046] At 0℃: F(y)=-60.988y 3 +655.8y 2 -2492.7y+3877.6;

[0047] Where y represents the DC internal resistance value DCR, and F(y) is the peak power.

[0048] As an alternative technical solution, the fitting relationship between DC internal resistance and state of charge (SOC) at different temperatures and different SOCs is substituted into the fitting relationship between the actual peak power and DC internal resistance at the corresponding temperature, thus obtaining the fitting relationship between the actual peak power and SOC at different temperatures and different SOCs.

[0049] A second aspect of the present invention provides a battery peak power fitting test system.

[0050] A battery peak power fitting test system includes:

[0051] The data acquisition module is configured to acquire peak discharge power data of the battery at different temperatures and different states of charge (SOC), including open circuit voltage, terminal voltage, and peak current value that meets the standard.

[0052] The DC internal resistance calculation module is configured to calculate the DC internal resistance under different states of charge (SOC) based on the open-circuit voltage, the terminal voltage, and the target peak current value.

[0053] The initial fitting module is configured to: fit different states of charge (SOC) with their corresponding DC internal resistance values ​​to obtain the fitting relationship between DC internal resistance values ​​and SOC values ​​under different temperatures and different SOC values.

[0054] The refitting module is configured to: calculate the true peak power value, refit the true peak power value with the DC internal resistance value, obtain the fitting relationship between the true peak power value and the DC internal resistance value at different temperatures, and then obtain the fitting relationship between the true peak power value and the state of charge (SOC) at different temperatures and different SOCs, thereby realizing the fitting test of the battery peak power.

[0055] A third aspect of the present invention provides a computer-readable storage medium.

[0056] A computer-readable storage medium having a program stored thereon, characterized in that, when executed by a processor, the program implements the steps in the battery peak power fitting test method as described in the first aspect.

[0057] A fourth aspect of the present invention provides an electronic device.

[0058] An electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that, when the processor executes the program, it implements the steps in the battery peak power fitting test method as described in the first aspect.

[0059] The present invention has the following beneficial effects:

[0060] 1. This invention provides a battery peak power fitting test method and system. The battery peak power fitting test method, based on DC internal resistance fitting, innovatively proposes a new lithium-ion battery peak power prediction model to predict the battery peak power. It can quickly and accurately obtain the peak discharge power of lithium-ion batteries under different environments and SOCs, which is more conducive to the rational optimization of battery use.

[0061] 2. Compared with existing technologies, the battery peak power fitting test method provided by this invention only requires fitting different states of charge (SOC) with corresponding DC internal resistance values ​​using DC internal resistance (DCR) to obtain the fitting relationship between DC internal resistance and SOC at different temperatures and SOCs; then fitting the actual peak power value with DC internal resistance value again to obtain the fitting relationship between actual peak power value and DC internal resistance value at different temperatures. This allows for the rapid and accurate determination of the battery peak discharge power at different temperatures and SOCs, which is more conducive to the rational use of the battery.

[0062] 3. The battery peak power fitting test method of the present invention has the advantages of being fast, efficient and accurate. It does not require a lot of test resources and time, which can greatly save test costs and improve efficiency, and can be promoted and applied on a large scale.

[0063] 4. The greatest advantage of this invention is that it can evaluate the peak discharge power of a single cell without having to perform cumbersome tests or be limited by various complex experimental conditions, and the error between the calculated value and the actual test value can be controlled within 2%.

[0064] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0065] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0066] Figure 1 This is a test flowchart of Embodiment 1 of the present invention. Detailed Implementation

[0067] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] Example 1:

[0069] Please see Figure 1 As shown, in order to calculate the peak discharge power of a lithium-ion battery, reduce the test time for obtaining the peak discharge power, and improve test efficiency, this embodiment provides a battery peak power fitting test method, which may include the following steps:

[0070] The peak discharge power data of the battery under different temperatures and different states of charge (SOC) were obtained through experiments, including open circuit voltage, terminal voltage and peak current value.

[0071] Based on the open-circuit voltage, terminal voltage, and peak current value, calculate the DC internal resistance value under different states of charge (SOC).

[0072] By fitting different states of charge (SOC) with their corresponding DC internal resistance values, the fitting relationship between DC internal resistance and SOC under different temperatures and different SOC values ​​is obtained.

[0073] The true peak power value is calculated, and then fitted with the DC internal resistance value again to obtain the fitting relationship between the true peak power value and the DC internal resistance value at different temperatures. In turn, the fitting relationship between the true peak power value and the state of charge (SOC) under different temperatures and different SOC values ​​is obtained, thus realizing the fitting test of the battery peak power.

[0074] More specifically, the battery peak discharge power data includes open-circuit voltage, terminal voltage, and peak current at the target level. These values ​​are measured experimentally. The specific experimental methods will be described in detail later.

[0075] In this embodiment, tests were conducted at 25°C, 45°C, and 0°C to obtain the SOC results at different temperatures. During the process, the open-circuit voltage V0, the terminal voltage V1, and the peak current value I were recorded, and then the DC internal resistance value under the corresponding SOC was calculated.

[0076] The method for calculating the DC internal resistance value is as follows:

[0077] DCR = (V0 - V1) / I * 1000;

[0078] Where V0 is the open-circuit voltage; V1 is the terminal voltage; I is the peak current value; and DCR is the DC internal resistance value.

[0079] Next, the DC internal resistance value and the corresponding DCR data for different states of charge (SOC) are fitted multiple times to obtain the fitting relationship between the DC internal resistance value and the SOC at different temperatures and SOCs. This yields the first model for calculating the SOC and DCR: Specifically,

[0080] At 25℃, 90% SOC - 20% SOC:

[0081] y1=0.8111x 2 -1.7768x + 1.8599;

[0082] At 25℃, 20% SOC - 5% SOC:

[0083] y2=20.932x 2 -13.256x + 3.3538;

[0084] At 45℃, 90% SOC - 30% SOC:

[0085] y3 = 0.5104x 2 -1.0554x + 1.2979;

[0086] At 45℃, 30% SOC - 5% SOC:

[0087] y4 = 15.397x 2 -8.7931x+2.2736;

[0088] At 0℃, 90% SOC - 30% SOC:

[0089] y5 = -7.726x 3 +18.099x 2 -15.074x + 6.23;

[0090] At 0℃, 30% SOC - 5% SOC:

[0091] y6 = 10.075x 2 The function expression for -4.5597x + 4.6651;

[0092] Where x represents the variable state of charge (SOC) and y represents the DC internal resistance (DCR).

[0093] The second step is through P 1＝ I*V1 yields the true peak power P1. Then, the DCR obtained in the first step is used as a variable to perform multiple fittings with the true peak power P1 result data to obtain the fitting relationship between the true peak power value and the DC internal resistance value at different temperatures, which is the final peak discharge calculation model. Specifically:

[0094] At 25℃: F(y)=-311.18y 3 +2248.3y 2 -5727.7y+5854;

[0095] At 45℃: F(y)=-1628.6y 3 +7739.2y 2 –13144y+8978.1;

[0096] At 0℃: F(y)=-60.988y 3 +655.8y 2 -2492.7y+3877.6;

[0097] Where y represents the DC internal resistance value DCR, and F(y) is the peak power.

[0098] After completing the above steps, the fitting relationship between the DC internal resistance value and the state of charge (SOC) at different temperatures and different SOCs is substituted into the fitting relationship between the actual peak power value and the DC internal resistance value at the corresponding temperature. This yields the fitting relationship between the actual peak power value and the state of charge (SOC) at different temperatures and different SOCs, thus enabling the fitting test of the battery peak power.

[0099] The peak discharge power data of the battery was obtained according to the experimental method, including:

[0100] Step 1: Select a batch of lithium batteries of the same capacity and discharge them at a constant current rate to the first set voltage value.

[0101] Step 2: Starting from the first set voltage value, perform constant current and constant voltage charging until the second set voltage value is reached;

[0102] Step 3: Starting from the second set voltage value, discharge at a set rate with constant current for different durations to bring the batch of lithium batteries to different states of charge (SOC).

[0103] Step 4: Place batches of lithium batteries with different states of charge (SOC) at different temperatures and record the open-circuit voltage of the lithium batteries.

[0104] Step 5: Set the constant current discharge time to the first set voltage value based on the reference value;

[0105] Step 6: Repeat steps 2 to 5 above, and find the peak current increment or decrement set value in step 5 each time. Record the terminal voltage and the peak current value that meets the standard during the process.

[0106] In this embodiment:

[0107] 1. Select a batch of 73Ah lithium batteries and let them stand at 25℃ for 30 minutes.

[0108] 2. Discharge to 2.5V at a constant current of 1C (73Ah);

[0109] 3. Let stand for 30 minutes;

[0110] 4. Charge to 3.65V using a constant current and constant voltage of 1C;

[0111] 5. Let stand for 30 minutes;

[0112] 6. Discharge at a constant current of 1C for Xmin (protection voltage 2.5V) and discharge to reach the set state of charge (SOC) as shown in Table 1 below;

[0113] Table 1 shows the correspondence between discharge time and state of charge (SOC).

[0114] SOC / % 90 80 70 60 50 X / min 6 12 18 24 30 SOC / % 40 30 20 10 5 X / min 24 18 12 6 3

[0115] 7. Let stand for 30 minutes (25℃, 45℃); let stand for 4 hours (0℃), and record the open circuit voltage V0 during the process;

[0116] 8. Discharge at a constant current of 800A for 30 seconds until the cutoff voltage is 2.5V;

[0117] 9. Let stand for 30 minutes.

[0118] Repeat steps 4 through 9 above, increasing or decreasing the peak current by 50A each time; record the terminal voltage V1 and the target peak current value I during the process. Thus, the open-circuit voltage, terminal voltage, and target peak current value are obtained using the above method.

[0119] Data for different temperatures (peak discharge power meters at 25℃, 45℃, and 0℃) were obtained using the above testing method. The data processing is as follows:

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127] The battery peak power fitting test method provided in this embodiment has the greatest advantage of being able to evaluate the peak discharge power of a single battery without performing cumbersome tests or being limited by various complex experimental conditions. Furthermore, the error between the calculated value and the actual test value can be controlled within 2%. It boasts advantages of speed, efficiency, and high accuracy, requiring minimal testing resources and time, thus significantly saving testing costs and improving efficiency, and can be widely promoted and applied. Compared with existing technologies, this embodiment can quickly and accurately obtain the battery peak discharge power rate simply by using the DC internal resistance (DCR), which is more conducive to the rational use of the battery.

[0128] Example 2

[0129] This embodiment discloses a battery peak power fitting test system.

[0130] A battery peak power fitting test system includes:

[0131] The data acquisition module is configured to acquire peak discharge power data of the battery at different temperatures and different states of charge (SOC), including open circuit voltage, terminal voltage, and peak current value that meets the standard.

[0132] The DC internal resistance calculation module is configured to calculate the DC internal resistance under different states of charge (SOC) based on the open-circuit voltage, the terminal voltage, and the target peak current value.

[0133] The initial fitting module is configured to: fit different states of charge (SOC) with their corresponding DC internal resistance values ​​to obtain the fitting relationship between DC internal resistance values ​​and SOC values ​​under different temperatures and different SOC values.

[0134] The refitting module is configured to: calculate the true peak power value, refit the true peak power value with the DC internal resistance value, obtain the fitting relationship between the true peak power value and the DC internal resistance value at different temperatures, and then obtain the fitting relationship between the true peak power value and the state of charge (SOC) at different temperatures and different SOCs, thereby realizing the fitting test of the battery peak power.

[0135] Example 3

[0136] The purpose of this embodiment is to provide a computer-readable storage medium.

[0137] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps in the battery peak power fitting test method as described in Embodiment 1 of this disclosure.

[0138] Example 4

[0139] The purpose of this embodiment is to provide an electronic device.

[0140] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the battery peak power fitting test method as described in Embodiment 1 of this disclosure.

[0141] The steps and methods involved in the apparatuses of Embodiments 2, 3, and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0142] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A battery peak power fitting test method, characterized in that, Includes the following steps: Acquire peak discharge power data of batteries at different temperatures and different states of charge (SOC), including open-circuit voltage, terminal voltage, and target peak current. The peak discharge power data of the battery was obtained through experimental methods, specifically including: Step 1: Select a batch of lithium batteries of the same capacity and discharge them at a constant current rate to the first set voltage value. Step 2: Starting from the first set voltage value, perform constant current and constant voltage charging until the second set voltage value is reached; Step 3: Starting from the second set voltage value, discharge at a set rate with constant current for different durations to bring the batch of lithium batteries to different states of charge (SOC). Step 4: Place batches of lithium batteries with different states of charge (SOC) at different temperatures and record the open-circuit voltage of the lithium batteries. Step 5: Set the constant current discharge time to the first set voltage value based on the reference value; Step 6: Repeat steps 2 to 5 above. In step 5, based on the baseline value, increase or decrease the current by the set value each time to find the peak current. Record the end voltage and the peak current value that meets the standard during the process. Based on the open-circuit voltage, terminal voltage, and peak current value, calculate the DC internal resistance value under different states of charge (SOC). By fitting different states of charge (SOC) with their corresponding DC internal resistance values, the fitting relationship between DC internal resistance and SOC under different temperatures and different SOC values ​​is obtained. The true peak power value is calculated, and then fitted with the DC internal resistance value again to obtain the fitting relationship between the true peak power value and the DC internal resistance value at different temperatures. In turn, the fitting relationship between the true peak power value and the state of charge (SOC) under different temperatures and different SOC values ​​is obtained, thus realizing the fitting test of the battery peak power.

2. The battery peak power fitting test method according to claim 1, characterized in that, The method for calculating the DC internal resistance value is as follows: DCR=(V0-V1) / I*1000; Where V0 is the open-circuit voltage; V1 is the terminal voltage; I is the peak current value; and DCR is the DC internal resistance value.

3. The battery peak power fitting test method according to claim 1, characterized in that, The fitting relationship between DC internal resistance and state of charge (SOC) at different temperatures and under different SOCs is as follows: At 25℃, 90% SOC - 20% SOC: y1 At 25℃, 20%SOC-5%SOC: y2= 20.932x 2 - 13.256x + 3.3538; At 45℃, 90% SOC - 30% SOC: y3 = 0.5104x 2 - 1.0554x + 1.2979 At 45℃, 30%SOC-5%SOC: y4 = 15.397x 2 - 8.7931x + 2.2736; At 0℃, 90% SOC - 30% SOC: y5= -7.726x 3 + 18.099x 2 - 15.074x + 6.23; At 0℃, 30%SOC-5%SOC: y6 = 10.075x 2 The function expression for -4.5597x + 4.6651; Where x represents the variable state of charge (SOC) and y represents the DC internal resistance (DCR).

4. The battery peak power fitting test method according to claim 1, characterized in that, The specific calculation method for the actual peak power value is as follows: P 1= I*V1 Where P1 is the actual peak power; V1 is the terminal voltage; and I is the target peak current value.

5. The battery peak power fitting test method according to claim 1, characterized in that, The fitting relationship between the actual peak power value and the DC internal resistance value at different temperatures is as follows: At 25℃: -311.18y 3 + 2248.3y 2 - 5727.7y + 5854; At 45℃: -1628.6y 3 + 7739.2y 2 – 13144y + 8978.1; At 0℃: -60.988y 3 + 655.8y 2 - 2492.7y + 3877.6; Where y represents the DC internal resistance value DCR, This represents peak power.

6. The battery peak power fitting test method according to claim 1, characterized in that, By substituting the fitting relationship between DC internal resistance and state of charge (SOC) at different temperatures and SOCs into the fitting relationship between the actual peak power and DC internal resistance at the corresponding temperature, the fitting relationship between the actual peak power and SOC at different temperatures and SOCs is obtained.

7. A battery peak power fitting test system, characterized in that, include: The data acquisition module is configured to acquire peak discharge power data of the battery at different temperatures and different states of charge (SOC), including open circuit voltage, terminal voltage, and peak current value that meets the standard. The peak discharge power data of the battery was obtained through experimental methods, specifically including: Step 1: Select a batch of lithium batteries of the same capacity and discharge them at a constant current rate to the first set voltage value. Step 2: Starting from the first set voltage value, perform constant current and constant voltage charging until the second set voltage value is reached; Step 3: Starting from the second set voltage value, discharge at a set rate with constant current for different durations to bring the batch of lithium batteries to different states of charge (SOC). Step 4: Place batches of lithium batteries with different states of charge (SOC) at different temperatures and record the open-circuit voltage of the lithium batteries. Step 5: Set the constant current discharge time to the first set voltage value based on the reference value; Step 6: Repeat steps 2 to 5 above. In step 5, based on the baseline value, increase or decrease the current by the set value each time to find the peak current. Record the end voltage and the peak current value that meets the standard during the process. The DC internal resistance calculation module is configured to calculate the DC internal resistance under different states of charge (SOC) based on the open-circuit voltage, the terminal voltage, and the target peak current value. The initial fitting module is configured to: fit different states of charge (SOC) with their corresponding DC internal resistance values ​​to obtain the fitting relationship between DC internal resistance values ​​and SOC values ​​under different temperatures and different SOC values. The refitting module is configured to: calculate the true peak power value, refit the true peak power value with the DC internal resistance value, obtain the fitting relationship between the true peak power value and the DC internal resistance value at different temperatures, and then obtain the fitting relationship between the true peak power value and the state of charge (SOC) at different temperatures and different SOCs, thereby realizing the fitting test of the battery peak power.

8. A computer-readable storage medium having a program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the battery peak power fitting test method as described in any one of claims 1-6.

9. An electronic device, comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the battery peak power fitting test method as described in any one of claims 1-6.

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