Methods and apparatus for determining the performance of power batteries, electronic equipment and storage media

Abstract

This invention discloses a method, apparatus, electronic device, and storage medium for determining the performance of a power battery. The method includes the following steps: acquiring historical data of the power battery during at least two charging processes; determining the dQ / dV curve and DC internal resistance corresponding to the charging process based on the historical data from one charging process; calculating the relative change rate of internal resistance capacity between any two charging processes; and determining the performance of the power battery based on the relative change rate of internal resistance capacity and the range of relative change rate of internal resistance capacity corresponding to a fault type. This invention, by combining the target peak value of the dQ / dV curve and the change in DC internal resistance during two charging processes, can effectively determine whether the performance of the power battery is abnormal.

Description

Technical Field

[0001] This invention relates to the field of safety diagnosis of power batteries, and particularly to a method and apparatus for determining the performance of power batteries, electronic equipment, and storage medium. Background Technology

[0002] Lithium-ion battery accidents are the result of a combination of thermodynamic and electrochemical processes: when the rate at which the overall heat is released from the lithium-ion battery exceeds the rate at which it dissipates heat, the battery temperature rises as heat accumulates. High temperatures increase the chemical activity of the internal materials, accelerating chemical reactions or introducing new side reactions, leading to the continued release of even more heat and creating a vicious cycle. Sustained temperature increases can cause the internal materials of the lithium-ion battery to melt or decompose, and in severe cases, can trigger serious malfunctions such as internal short circuits and thermal runaway.

[0003] Most internal failures in lithium batteries are caused by improper use, and various forms of abuse greatly increase the probability of lithium battery accidents. Among these, improper charging practices, such as overcharging, high temperature, low temperature, and high rate charging, frequently lead to electric vehicle fires.

[0004] Currently, research on lithium battery overcharge failures mainly employs abuse experiments with high rates and deep overcharge degrees. Such experiments can cause large-scale lithium plating and temperature rise on the negative electrode of the test battery within a short time, rapidly leading to internal short circuits and thermal runaway failures. This is beneficial for assessing battery safety characteristics, but it is not conducive to observing the external characteristic changes throughout the entire process from the onset of a failure to its development into actual failure. However, in real-world scenarios, lower rates and shallower overcharge degrees mean that phenomena such as negative electrode lithium plating are insufficient to trigger sudden failures. Nevertheless, events such as electrolyte solvent co-intercalation and binder decomposition can still occur, leading to the peeling off of graphite from the negative electrode. With continued cycling and the continuous loss of negative electrode active material, the negative electrode lithium plating phenomenon intensifies, resulting in the loss of lithium-ionized active material and posing a risk of short-term failures. Therefore, existing experiments with high rates and deep overcharge degrees cannot assess the safety characteristics of lithium batteries in real-world scenarios. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art in that it is impossible to assess the safety characteristics of lithium batteries in actual situations, and to provide a method and device for determining the performance of power batteries, electronic devices and storage media.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] The first aspect of the present invention provides a method for determining the performance of a power battery, comprising the following steps:

[0008] Acquire historical data of the power battery during at least two charging processes;

[0009] The dQ / dV curve and DC internal resistance corresponding to the charging process are determined based on historical data from a single charging process.

[0010] Calculate the relative change rate of internal resistance and capacity during any two charging processes; wherein, the relative change rate of internal resistance and capacity is determined based on the difference between the first DC internal resistance and the second DC internal resistance, and the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve. The first DC internal resistance and the first dQ / dV curve correspond to one charging process, and the second DC internal resistance and the second dQ / dV curve correspond to another charging process. The two peaks corresponding to the two target peak values ​​are used to characterize the same electrochemical reaction.

[0011] The performance of the power battery is determined based on the relative change rate of internal resistance capacity and the range of relative change rates of internal resistance capacity corresponding to the fault type.

[0012] Optionally, the step of determining the performance of the power battery based on the relative change rate of internal resistance and capacity and the range of relative change rates of internal resistance and capacity corresponding to the fault type specifically includes:

[0013] Determine whether the relative rate of change of internal resistance capacity falls within the range of relative rate of change of internal resistance capacity corresponding to the fault type;

[0014] If so, then it is determined that the power battery is abnormal in performance, and / or that the power battery has a fault corresponding to the fault type;

[0015] If not, then the power battery is confirmed to be functioning normally.

[0016] Optionally, the performance determination method further includes the following steps:

[0017] If the relative change rate of internal resistance capacity falls within the range of the relative change rate of internal resistance capacity corresponding to the fault type, a prompt message will be output.

[0018] The prompt information is used to characterize the abnormal performance of the power battery and / or the presence of a fault in the power battery corresponding to the fault type.

[0019] Optionally, the step of calculating the relative rate of change of internal resistance and capacity during any two charging processes specifically includes:

[0020] The target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve are determined based on the initial charge level during the two charging processes.

[0021] A second aspect of the present invention provides a power battery performance determination apparatus, comprising:

[0022] The data acquisition module is used to acquire historical data of the power battery during at least two charging processes;

[0023] The first determining module is used to determine the dQ / dV curve and DC internal resistance corresponding to the charging process based on historical data during a single charging process.

[0024] The rate of change calculation module is used to calculate the relative rate of change of internal resistance capacity during any two charging processes. The relative rate of change of internal resistance capacity is determined based on the difference between the first DC internal resistance and the second DC internal resistance, as well as the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve. The first DC internal resistance and the first dQ / dV curve correspond to one charging process, and the second DC internal resistance and the second dQ / dV curve correspond to another charging process. The two peaks corresponding to the two target peak values ​​are used to characterize the same electrochemical reaction.

[0025] The second determining module is used to determine the performance of the power battery based on the relative change rate of internal resistance capacity and the range of relative change rate of internal resistance capacity corresponding to the fault type.

[0026] Optionally, the second determining module is specifically used to determine whether the relative change rate of internal resistance capacity falls within the range of relative change rate of internal resistance capacity corresponding to the fault type, and if yes, determine that the performance of the power battery is abnormal, and / or determine that the power battery has a fault corresponding to the fault type; and if no, determine that the performance of the power battery is normal.

[0027] Optionally, the performance determination device further includes an information prompting module, used to output prompting information when the relative change rate of internal resistance and capacity falls within the range of the relative change rate of internal resistance and capacity corresponding to the fault type;

[0028] The prompt information is used to characterize the abnormal performance of the power battery and / or the presence of a fault in the power battery corresponding to the fault type.

[0029] Optionally, the rate of change calculation module is further configured to determine the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve based on the initial charge during the two charging processes.

[0030] A third aspect of the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the power battery performance determination method as described in the first aspect.

[0031] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the power battery performance determination method as described in the first aspect.

[0032] Based on common knowledge in the field, the above optional conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0033] The significant advantages of this invention are as follows: Based on historical data from at least two charging processes of the power battery, the dQ / dV curve and DC internal resistance corresponding to each charging process are determined. Furthermore, the relative change rate of the power battery's internal resistance capacity is calculated based on the target peak value of the dQ / dV curve and the DC internal resistance for any two charging processes. Finally, the performance of the power battery is determined based on whether this relative change rate falls within the range corresponding to the fault type. Combining the target peak value of the dQ / dV curve and the change in DC internal resistance during two charging processes effectively determines whether the power battery's performance is abnormal. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the incremental capacity curve of a power battery under normal aging, provided for an embodiment of the present invention.

[0035] Figure 2 This is a schematic diagram of the incremental capacity curve of a power battery under overcharge aging, provided in an embodiment of the present invention.

[0036] Figure 3 This is a flowchart of a method for determining the performance of a power battery according to Embodiment 1 of the present invention.

[0037] Figure 4 A flowchart of another method for determining the performance of a power battery provided in Embodiment 1 of the present invention.

[0038] Figure 5 This is a schematic diagram of the structure of a power battery performance determination device provided in Embodiment 1 of the present invention.

[0039] Figure 6 This is a schematic diagram of the structure of an electronic device provided in Embodiment 2 of the present invention. Detailed Implementation

[0040] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0041] Power batteries exhibit different behaviors under different aging mechanisms. Taking lithium batteries as an example, the main behaviors include loss of delithiated negative electrode active material (LAMdene), loss of cycle lithium (LLI), loss of lithiated negative electrode active material (LAMline), and increase in DC internal resistance.

[0042] Research has revealed that the peaks of the dQ / dV curve exhibit different changes under different aging mechanisms; some peaks decline, some rise, and others shift. The dQ / dV curve, also known as the incremental capacity curve or differential capacity curve, is used to calculate the change in battery capacity within a constant voltage interval; it is the ratio of the measured capacity difference between two consecutive measurements to the corresponding voltage difference.

[0043] Figure 1 Used to show the incremental capacity curve of a power battery under normal aging. Figure 2 Used to illustrate the incremental capacity curve of a power battery under overcharge aging. For example... Figure 1 and 2 As shown, overcharging aging will cause the peaks ① and ② of the dQ / dV curve to rise and the peaks ② and ③ to fall.

[0044] Based on this, this embodiment combines the target peak value of the dQ / dV curve and the change in DC internal resistance during two charging processes to determine whether the performance of the power battery is abnormal.

[0045] Example 1

[0046] Figure 3 This is a flowchart illustrating a method for determining the performance of a power battery according to this embodiment. This method can be executed by a power battery performance determination device, which can be implemented through software and / or hardware. The power battery performance determination device can be part or all of an electronic device. In this embodiment, the electronic device can be a personal computer (PC), such as a desktop computer, all-in-one computer, laptop computer, tablet computer, etc., or it can be a mobile phone, wearable device, PDA, or other terminal device. The following description uses an electronic device as the execution subject to illustrate the power battery performance determination method provided in this embodiment.

[0047] like Figure 3 As shown, the method for determining the performance of a power battery provided in this embodiment may include the following steps S1 to S4:

[0048] Step S1: Obtain historical data of the power battery during at least two charging processes.

[0049] The power battery mentioned above is the power source that provides power to the tool. It mainly refers to the storage battery that provides power to electric vehicles, electric trains, electric bicycles, etc., and can be lithium batteries, nickel-metal hydride batteries, etc.

[0050] In practice, historical data during the charging process can include the voltage U of the power battery.k Current I, time T k Information such as U. k Let T be the voltage sampled at time k. k The time for sampling at the k-th time step.

[0051] Step S2: Determine the dQ / dV curve and DC internal resistance corresponding to the charging process based on historical data from a single charging process.

[0052] Specifically, the dQ / dV value can be calculated using the following formula, and the dQ / dV curve can be obtained from several dQ / dV values:

[0053]

[0054] Where, Δt=T k+1 -T k ΔV = U represents the time interval between two consecutive samplings. k+1 -U k This represents the voltage difference between two consecutive samples.

[0055] In practical implementation, the DC internal resistance can be extracted using a charging pulse method. Specifically, during each historical charging process of the power battery, when the charge reaches Q1, it is first left to rest for a period of time, then charged with a pulse current for a period of time, and then left to rest again. Q1 can be set according to actual conditions, for example, it can be set to 90%, 95%, etc. To improve the accuracy of extracting the DC internal resistance, the resting time can be set according to the duration of electrochemical polarization, for example, it can be set to rest for 5 minutes or 10 minutes. The charging time can also be set according to actual conditions, for example, it can be set to charge for 10 seconds. The value of the pulse current can be based on the maximum allowable current I of the power battery. max Configure it, for example, you can set it to 75% I max .

[0056] Specifically, the DC internal resistance R of the power battery during the nth charging process can be calculated using the following formula. n :

[0057]

[0058] Where ΔU is the voltage rise at the instant of the pulse during the nth charging process, that is, the voltage difference after charging with pulse current compared to before charging with pulse current.

[0059] Step S3: Calculate the relative rate of change of internal resistance and capacity during any two charging processes.

[0060] The relative change rate of internal resistance capacity is determined based on the difference between the first DC internal resistance and the second DC internal resistance, as well as the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve. The first DC internal resistance and the first dQ / dV curve correspond to one charging process, while the second DC internal resistance and the second dQ / dV curve correspond to another charging process. The two peaks corresponding to the two target peak values ​​are used to characterize the same electrochemical reaction.

[0061] In specific implementation, the relative change rate of internal resistance capacity can be the ratio of the difference between the first DC internal resistance and the second DC internal resistance to the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve, or it can be the ratio of the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve to the difference between the first DC internal resistance and the second DC internal resistance.

[0062] The dQ / dV curve can have multiple peaks, each representing an electrochemical reaction. If the initial charge of the power battery during charging is different, the number of peaks in the dQ / dV curve may differ. In one optional embodiment of step S3, the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve are determined based on the initial charge values ​​during the two charging processes.

[0063] In practice, if the initial charge level in both charging processes is less than the preset charge level, the corresponding peak is determined based on the preset charge level, and the peak value of the peak is taken as the target peak value. For example, if the initial charge level in both charging processes is less than 30%, the third peak value of the first dQ / dV curve is taken as the target peak value of the first dQ / dV curve, and the third peak value of the second dQ / dV curve is taken as the target peak value of the second dQ / dV curve.

[0064] In a specific example, the third peak of the dQ / dV curve corresponding to the nth charging process of the power battery is M. n And the DC internal resistance is R n The third peak of the dQ / dV curve corresponding to the m-th charging process is M. m And the DC internal resistance is R m Calculate the relative change rate K of the internal resistance capacity of the power battery according to the following formula. mn :

[0065]

[0066] Step S4: Determine the performance of the power battery based on the relative change rate of internal resistance capacity and the range of relative change rate of internal resistance capacity corresponding to the fault type.

[0067] Different fault types correspond to different ranges of relative change rates of internal resistance and capacitance. In specific implementations, the fault types may include overcharging, high temperature, low temperature, and high rate.

[0068] A lithium battery pack of the same type and rated capacity as the power battery can be selected for a control experiment, including single-variable experiments such as overcharge aging, high-temperature aging, low-temperature aging, and high-rate aging. Each single-variable experiment corresponds to a fault type. For each single-variable experiment, historical data of the lithium battery pack during the charging process is obtained, and steps S2 and S3 are executed to calculate multiple relative changes in internal resistance capacity. The range of relative changes in internal resistance capacity is obtained based on the maximum and minimum values ​​of these values.

[0069] It should be noted that battery information, such as battery type, rated capacity, and maximum single-cell voltage (V), can be obtained through GB / T 27930 "Communication Protocol between Off-board Conductive Charger and Battery Management System for Electric Vehicles". max The maximum allowable current I of the power battery max Recommended current I for power batteries c wait.

[0070] In one alternative implementation, such as Figure 4 As shown, step S4 specifically includes the following steps S41 to S43:

[0071] Step S41: Determine whether the relative change rate of the internal resistance capacity falls within the range of the relative change rate of the internal resistance capacity corresponding to the fault type. If yes, proceed to step S42; otherwise, proceed to step S43.

[0072] Specifically, if the relative rate of change of internal resistance is less than or equal to the maximum value of the range of relative rate of change of internal resistance corresponding to the fault type, and greater than or equal to the minimum value of the range of relative rate of change of internal resistance corresponding to the fault type, then the relative rate of change of internal resistance falls within the range of relative rate of change of internal resistance corresponding to the fault type. If the relative rate of change of internal resistance is greater than the maximum value of the range of relative rate of change of internal resistance corresponding to the fault type, or less than the minimum value of the range of relative rate of change of internal resistance corresponding to the fault type, then the relative rate of change of internal resistance does not fall within the range of relative rate of change of internal resistance corresponding to the fault type.

[0073] In the specific implementation of step S41, for each fault type, it is determined whether the relative change rate of the internal resistance capacity falls within the range of the relative change rate of the internal resistance capacity corresponding to the fault type. If the relative change rate of the internal resistance capacity falls within the range of the relative change rate of the internal resistance capacity corresponding to any fault type, then step S42 is executed; if the relative change rate of the internal resistance capacity does not fall within the range of the relative change rate of the internal resistance capacity corresponding to all fault types, then step S43 is executed.

[0074] Step S42: Determine the performance abnormality of the power battery.

[0075] In the specific implementation of step S42, it can be further determined that the power battery has a fault corresponding to the fault type. For example, it can be determined that the power battery is experiencing overcharging, high temperature, or other operating conditions.

[0076] In the specific implementation of step S42, further prompting information may be output. This prompting information is used to characterize the performance abnormality of the power battery and / or the presence of a fault in the power battery corresponding to the fault type, thereby providing a warning to the user. Specifically, the prompting information may be sound, light, vibration, voice, etc.

[0077] Step S43: Confirm that the performance of the power battery is normal.

[0078] In a specific example, the relative change rate of internal resistance capacity corresponding to high temperature ranges from 1.13 to 5.29, while the relative change rate of internal resistance capacity corresponding to overcharging ranges from 6.05 to 43.37. If the calculated relative change rate of internal resistance capacity of the power battery is 3.52, then the power battery is determined to have a high-temperature fault.

[0079] This embodiment determines the dQ / dV curve and DC internal resistance corresponding to the charging process based on historical data from at least two charging processes of the power battery. It then calculates the relative change rate of the power battery's internal resistance capacity based on the target peak value of the dQ / dV curve and the DC internal resistance for any two charging processes. Finally, it determines the performance of the power battery by whether the relative change rate falls within the range corresponding to the fault type. Combining the target peak value of the dQ / dV curve and the change in DC internal resistance during two charging processes can effectively determine whether the power battery's performance is abnormal.

[0080] like Figure 5 As shown, this embodiment also provides a power battery performance determination device 80, including a data acquisition module 81, a first determination module 82, a rate of change calculation module 83, and a second determination module 84.

[0081] The data acquisition module is used to acquire historical data of the power battery during at least two charging processes. The first determination module is used to determine the dQ / dV curve and DC internal resistance corresponding to the charging process based on the historical data during one charging process. The rate of change calculation module is used to calculate the relative rate of change of internal resistance capacity during any two charging processes. The relative rate of change of internal resistance capacity is determined based on the difference between the first DC internal resistance and the second DC internal resistance, and the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve. The first DC internal resistance and the first dQ / dV curve correspond to one charging process, and the second DC internal resistance and the second dQ / dV curve correspond to another charging process. The two peaks corresponding to the two target peak values ​​are used to characterize the same electrochemical reaction. The second determination module is used to determine the performance of the power battery based on the relative rate of change of internal resistance capacity and the range of relative rate of change of internal resistance capacity corresponding to the fault type.

[0082] In one optional implementation, the second determining module is specifically used to determine whether the relative change rate of internal resistance capacity falls within the range of relative change rate of internal resistance capacity corresponding to the fault type, and if yes, determine that the performance of the power battery is abnormal, and / or determine that the power battery has a fault corresponding to the fault type; and if no, determine that the performance of the power battery is normal.

[0083] In one optional embodiment, the performance determination device further includes an information prompting module, used to output prompting information when the relative change rate of internal resistance capacity falls within the range of the relative change rate of internal resistance capacity corresponding to the fault type. The prompting information is used to characterize the performance abnormality of the power battery and / or the presence of a fault in the power battery corresponding to the fault type.

[0084] In one optional implementation, the rate of change calculation module is further configured to determine the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve based on the initial charge during the two charging processes.

[0085] It should be noted that the power battery performance determination device in this embodiment can be a separate chip, chip module or electronic device, or it can be a chip or chip module integrated into an electronic device.

[0086] Regarding the various modules / units included in the power battery performance determination device described in this embodiment, they may be software modules / units, hardware modules / units, or a combination of both.

[0087] Example 2

[0088] Figure 6This is a schematic diagram of the structure of an electronic device provided in this embodiment. The electronic device includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the power battery performance determination method of Embodiment 1. The electronic device provided in this embodiment can be a personal computer, such as a desktop computer, all-in-one computer, laptop computer, tablet computer, etc., and can also be a mobile phone, wearable device, PDA, or other terminal device. Figure 6 The electronic device 3 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0089] The components of the electronic device 3 may include, but are not limited to: at least one processor 4, at least one memory 5, and a bus 6 connecting different system components (including memory 5 and processor 4).

[0090] Bus 6 includes a data bus, an address bus, and a control bus.

[0091] The memory 5 may include volatile memory, such as random access memory (RAM) 51 and / or cache memory 52, and may further include read-only memory (ROM) 53.

[0092] The memory 5 may also include a program / utility 55 having a set (at least one) of program modules 54, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0093] The processor 4 executes various functional applications and data processing by running computer programs stored in the memory 5, such as the power battery performance determination method in Embodiment 1 above.

[0094] Electronic device 3 can also communicate with one or more external devices 7 (e.g., keyboard, pointing device, etc.). This communication can be performed through input / output (I / O) interface 8. Furthermore, electronic device 3 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 9. Figure 6 As shown, network adapter 9 communicates with other modules of electronic device 3 via bus 6. It should be understood that, although... Figure 6Not shown, it can be combined with electronic device 3 to use other hardware and / or software modules, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems.

[0095] It should be noted that although several units / modules or sub-units / modules of the electronic device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functions of one unit / module described above can be further divided and embodied by multiple units / modules.

[0096] Example 3

[0097] This embodiment provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the power battery performance determination method of Embodiment 1.

[0098] The readable storage medium may be more specifically adopted, including but not limited to: portable disk, hard disk, random access memory, read-only memory, erasable programmable read-only memory, optical storage device, magnetic storage device, or any suitable combination thereof.

[0099] In a possible implementation, the present invention can also be implemented as a program product comprising program code, which, when the program product is run on an electronic device, causes the electronic device to execute the power battery performance determination method of Embodiment 1.

[0100] The program code for executing the present invention can be written in any combination of one or more programming languages. The program code can be executed entirely on an electronic device, partially on an electronic device, as a standalone software package, partially on an electronic device and partially on a remote device, or entirely on a remote device.

[0101] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for determining the performance of a power battery, characterized in that, Includes the following steps: Acquire historical data of the power battery during at least two charging processes; The dQ / dV curve and DC internal resistance corresponding to the charging process are determined based on historical data from a single charging process. Calculate the relative change rate of internal resistance and capacity during any two charging processes; wherein, the relative change rate of internal resistance and capacity is determined based on the difference between the first DC internal resistance and the second DC internal resistance, and the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve. The first DC internal resistance and the first dQ / dV curve correspond to one charging process, and the second DC internal resistance and the second dQ / dV curve correspond to another charging process. The two peaks corresponding to the two target peak values ​​are used to characterize the same electrochemical reaction. The performance of the power battery is determined based on the relative change rate of internal resistance capacity and the range of relative change rates of internal resistance capacity corresponding to the fault type.

2. The performance determination method as described in claim 1, characterized in that, The step of determining the performance of the power battery based on the relative change rate of internal resistance and capacity and the range of the relative change rate of internal resistance and capacity corresponding to the fault type specifically includes: Determine whether the relative rate of change of internal resistance capacity falls within the range of relative rate of change of internal resistance capacity corresponding to the fault type; If so, then it is determined that the power battery is abnormal in performance, and / or that the power battery has a fault corresponding to the fault type; If not, then the power battery is confirmed to be functioning normally.

3. The performance determination method as described in claim 2, characterized in that, The performance determination method further includes the following steps: If the relative change rate of internal resistance capacity falls within the range of the relative change rate of internal resistance capacity corresponding to the fault type, a prompt message will be output. The prompt information is used to characterize the abnormal performance of the power battery and / or the presence of a fault in the power battery corresponding to the fault type.

4. The performance determination method according to any one of claims 1-3, characterized in that, The step of calculating the relative rate of change of internal resistance and capacity during any two charging processes specifically includes: The target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve are determined based on the initial charge level during the two charging processes.

5. A device for determining the performance of a power battery, characterized in that, include: The data acquisition module is used to acquire historical data of the power battery during at least two charging processes; The first determining module is used to determine the dQ / dV curve and DC internal resistance corresponding to the charging process based on historical data during a single charging process. The rate of change calculation module is used to calculate the relative rate of change of internal resistance capacity during any two charging processes. The relative rate of change of internal resistance capacity is determined based on the difference between the first DC internal resistance and the second DC internal resistance, as well as the difference between the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve. The first DC internal resistance and the first dQ / dV curve correspond to one charging process, and the second DC internal resistance and the second dQ / dV curve correspond to another charging process. The two peaks corresponding to the two target peak values ​​are used to characterize the same electrochemical reaction. The second determining module is used to determine the performance of the power battery based on the relative change rate of internal resistance capacity and the range of relative change rate of internal resistance capacity corresponding to the fault type.

6. The performance determination device as described in claim 5, characterized in that, The second determining module is specifically used to determine whether the relative change rate of internal resistance capacity falls within the range of relative change rate of internal resistance capacity corresponding to the fault type, and if yes, to determine that the performance of the power battery is abnormal, and / or to determine that the power battery has a fault corresponding to the fault type; and if no, to determine that the performance of the power battery is normal.

7. The performance determination apparatus as described in claim 6, characterized in that, The performance determination device also includes an information prompting module, which is used to output prompting information when the relative change rate of internal resistance capacity falls within the range of the relative change rate of internal resistance capacity corresponding to the fault type. The prompt information is used to characterize the abnormal performance of the power battery and / or the presence of a fault in the power battery corresponding to the fault type.

8. The performance determination apparatus as described in any one of claims 5-7, characterized in that, The rate of change calculation module is also used to determine the target peak value of the first dQ / dV curve and the target peak value of the second dQ / dV curve based on the initial charge during the two charging processes.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for determining the performance of a power battery as described in any one of claims 1-4.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for determining the performance of the power battery as described in any one of claims 1-4.

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