Charging strategy determination method, system and equipment of power battery and medium

Abstract

The invention relates to the technical field of vehicles, and discloses a charging strategy determination method, system and device of a power battery and a medium. The method for determining the charging strategy of the power battery comprises the steps that under a preset condition, charging and discharging operation is carried out on a plurality of power batteries of the same type, and different multiplying power currents are used in the charging process of the power batteries; after multiple charging and discharging operations, evaluating the structural integrity of each power battery; and taking the multiplying power current corresponding to the power battery with the optimal structure completeness as the preset charging current of the power battery under the preset condition. By adopting the embodiment of the invention, the expansion stress and the change rate thereof in the charging process can be reduced, and the mechanical impact on the microstructure of the battery can be reduced, so that the comprehensive optimization of the charging speed, the cycle life, the safety risk and other properties of the battery can be achieved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a method, system, device and medium for determining a charging strategy for a power battery. Background Art

[0002] When the power battery is a lithium iron phosphate composite material system, the reaction activity of the lithium iron phosphate material in the lithium iron phosphate composite material is mainly in the low voltage area, while the reaction activity of the lithium manganese phosphate material is mainly in the high voltage area. Therefore, the current charging strategy limits the amount of electricity charged into the power battery and cannot charge enough electricity. Summary of the invention

[0003] Based on this, it is necessary to provide a method, system, equipment and medium for determining a charging strategy for a power battery in response to the above-mentioned technical problems, which can reduce the expansion stress and its change rate during the charging process, and reduce the mechanical impact on the battery microstructure, thereby achieving comprehensive optimization of multiple aspects of battery performance such as charging speed, cycle life and safety risks.

[0004] In a first aspect, a method for determining a charging strategy of a power battery is provided, comprising:

[0005] Under preset conditions, charging and discharging operations are performed on a plurality of power batteries of the same type, wherein different rate currents are used for charging the plurality of power batteries;

[0006] After multiple charge and discharge operations, the structural integrity of each power battery is evaluated;

[0007] The rate current corresponding to the power battery with the best structural completeness is used as the preset charging current of the power battery under the preset conditions.

[0008] In some examples, evaluating the structural integrity of each power battery includes:

[0009] Dismantle the power battery;

[0010] Obtain microstructure characterization data of the pole piece of the disassembled power battery;

[0011] The microstructural integrity of the pole piece is evaluated based on the microstructural characterization data of the pole piece of the power battery.

[0012] In some examples, obtaining microstructure characterization data of a pole piece of a disassembled power battery includes:

[0013] The microstructure of the pole piece of the disassembled power battery is characterized by using any one of a scanning electron microscope SEM, a transmission electron microscope TEM and a focused ion beam / scanning electron microscope FIB / SEM to obtain microstructure characterization data of the pole piece of the power battery.

[0014] In some examples, this also includes:

[0015] Detect the expansion force and voltage of each power battery during charging;

[0016] Generate characteristic curves of different rate currents with respect to the expansion force and voltage according to the detected expansion force and voltage, wherein the characteristic curve of the preset charging current with respect to the expansion force and voltage is a first characteristic curve, and characteristic curves of other rate currents with respect to the expansion force and voltage except the preset charging current are respectively a second characteristic curve;

[0017] Based on the charging speed and the expansion force, the first characteristic curve and each second characteristic curve are respectively compared in sections, and a section charging current that meets the target principle is selected in each section;

[0018] The segmented charging currents of all the segments are combined to generate a step charging current for the power battery under the preset conditions.

[0019] In some examples, based on the charging speed and the expansion force, the first characteristic curve and each second characteristic curve are respectively compared in sections, and a sectioned charging current that meets the target principle is selected in each section, including:

[0020] In each comparison, all second characteristic curves are grouped according to whether the curve trend is similar to the first characteristic curve, so as to obtain a first trend curve group with similar trends and a second trend curve group with dissimilar trends;

[0021] The current with the highest rate among all rate currents corresponding to the first trend curve group and the preset charging current is selected as the first characteristic current, and the current with the highest rate among all rate currents corresponding to the second trend curve group is selected as the second characteristic current;

[0022] The current with the lowest rate of change of expansion force between the first characteristic current and the second characteristic current is selected as the segmented charging current for the segment.

[0023] In some examples, before segmentally comparing the first characteristic curve and each second characteristic curve based on the charging speed and the expansion force, the method includes:

[0024] The first characteristic curve and the second characteristic curve are segmented according to the principle of equal division or with the intersection point between the first characteristic curve and the second characteristic curve as the segmentation point.

[0025] In some examples, the characteristic curve is a first-order differential dP / dV curve, a first-order differential dP / dSOC curve, or a second-order differential d2P / dV2 curve, wherein dP is the first-order differential of the expansion force of the lithium-ion battery, dV is the first-order differential of the voltage of the lithium-ion battery, and dSOC is the first-order differential of the capacity of the lithium-ion battery.

[0026] In a second aspect, a system for determining a charging strategy of a power battery is provided, comprising:

[0027] A charge and discharge control module, used to perform charge and discharge operations on a plurality of power batteries of the same type under preset conditions, wherein the plurality of power batteries use different rate currents when being charged;

[0028] An evaluation module for evaluating the structural integrity of each power battery after multiple charge and discharge operations;

[0029] The determination module is used to use the rate current corresponding to the power battery with the best structural completeness as the preset charging current of the power battery under the preset conditions.

[0030] In a third aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for determining a charging strategy for a power battery according to the first aspect above is implemented.

[0031] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and the program is executed by a processor to implement the method for determining a charging strategy for a power battery according to the first aspect above.

[0032] By adopting the embodiments of the present application, a more suitable charging current can be determined, which is conducive to charging the power battery with the determined charging current. The expansion stress and its change rate during the charging process can be reduced, and the mechanical impact on the battery microstructure can be reduced, thereby achieving comprehensive optimization of multiple aspects of battery performance such as charging speed, cycle life and safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0034] Figure 1 A flowchart of a method for determining a charging strategy for a power battery provided in an embodiment of the present application;

[0035] Figure 2 Another flow chart of the method for determining the charging strategy of a power battery provided in an embodiment of the present application;

[0036] Figure 3A schematic diagram of a dP / dV curve and a dP / dSOC curve in a method for determining a charging strategy for a power battery provided in an embodiment of the present application;

[0037] Figure 4 It is a schematic diagram for comparing the optimization of battery life and expansion force using the method of an embodiment of the present application;

[0038] Figure 5 A structural block diagram of a system for determining a charging strategy for a power battery provided in an embodiment of the present application;

[0039] Figure 6 A structural block diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The present application is further described in detail below in conjunction with the embodiments and drawings. It is to be understood that the specific embodiments described herein are only used to explain the relevant application, rather than to limit the application. It is also necessary to explain that, for ease of description, only the parts related to the application are shown in the drawings.

[0041] It should be noted that, in the absence of conflict, the embodiments of the present application, that is, the features of the embodiments, can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0042] The following describes in detail a method, system, device and medium for determining a charging strategy for a power battery according to an embodiment of the present application in conjunction with the accompanying drawings.

[0043] Figure 1 FIG. 1 is a flow chart of a method for determining a charging strategy for a power battery according to an embodiment of the present application. Figure 1 As shown, a method for determining a charging strategy for a power battery according to an embodiment of the present application includes the following steps:

[0044] S101: Under preset conditions, charge and discharge operations are performed on a plurality of power batteries of the same type, respectively, wherein the plurality of power batteries are charged using different rate currents.

[0045] Multiple power batteries of the same type are, for example, lithium iron manganese phosphate composite material system batteries. Generally speaking, when the power battery is a lithium iron manganese phosphate composite material system, the reaction activity of the lithium iron phosphate material in the lithium iron manganese phosphate composite material is mainly in the low voltage area, while the reaction activity of the lithium manganese phosphate material is mainly in the high voltage area, so the first material activity interval is the lithium iron phosphate material interval; the second material activity interval is the lithium manganese phosphate material interval. At present, charging the battery based on the charging strategy corresponding to the material activity interval generally includes: determining that the material activity interval is the lithium manganese phosphate material interval, charging with the maximum output current of the charging device as the charging current until the battery voltage meets the full charge cut-off condition; and performing multiple constant voltage charging according to the preset full charge cut-off voltage. When the battery state enters the lithium manganese phosphate material interval, it means that the battery charge has entered the high-end SOC interval. The polarization impedance of the battery mainly comes from the positive electrode material. Under high current conditions, the negative electrode has not yet reached the lithium plating potential, and the battery quickly reaches the full charge cut-off voltage due to the large positive electrode polarization. It can be seen that in the lithium manganese phosphate material interval, the charging current of the battery can be unlimited. Therefore, this embodiment uses the maximum output current of the charging device as the charging current to charge until the battery voltage meets the full charge cut-off condition to maximize the charging speed, and then performs multiple constant voltage charging according to the full charge cut-off voltage to ensure that the battery is charged with sufficient power.

[0046] Taking lithium iron manganese phosphate composite material system batteries as an example, the present application first charges and discharges multiple lithium iron manganese phosphate composite material system batteries separately under preset conditions, wherein each lithium iron manganese phosphate composite material system battery is charged using a different rate current, and the preset conditions include but are not limited to the surrounding ambient temperature and initial voltage range of the lithium iron manganese phosphate composite material system batteries.

[0047] S102: After multiple charge and discharge operations, evaluate the structural integrity of each power battery.

[0048] In one embodiment of the present application, evaluating the structural integrity of each power battery includes: disassembling the power battery; obtaining microstructural characterization data of the pole piece of the disassembled power battery; and evaluating the microstructural integrity of the pole piece according to the microstructural characterization data of the pole piece of the power battery. In this example, obtaining the microstructural characterization data of the pole piece of the disassembled power battery includes: using any one of a scanning electron microscope SEM, a transmission electron microscope TEM, and a focused ion beam / scanning electron microscope FIB / SEM to perform microstructural characterization on the pole piece of the disassembled power battery to obtain the microstructural characterization data of the pole piece of the power battery.

[0049] Specifically, after multiple charges and discharges, the structural integrity of different lithium manganese iron phosphate composite material system batteries is evaluated; the rate current corresponding to the lithium manganese iron phosphate composite material system battery with the best structural integrity is selected as the preset charging current of the lithium manganese iron phosphate composite material system battery under the preset conditions.

[0050] Among them, evaluating the structural integrity of different lithium iron manganese phosphate composite material system batteries includes: disassembling lithium iron manganese phosphate composite material system batteries that have been charged and discharged multiple times; performing microstructural characterization on the pole pieces of the disassembled lithium iron manganese phosphate composite material system batteries; and evaluating the microstructural integrity of the pole pieces based on the microstructural characterization data of the pole pieces. In a specific example, performing microstructural characterization on the pole pieces of the disassembled lithium iron manganese phosphate composite material system batteries includes: performing microstructural characterization on the pole pieces of the disassembled lithium iron manganese phosphate composite material system batteries using any one of a scanning electron microscope SEM, a transmission electron microscope TEM, and a focused ion beam / scanning electron microscope FIB / SEM.

[0051] S103: The rate current corresponding to the power battery with the best structural integrity is selected as the preset charging current of the power battery under the preset conditions. That is, the rate current corresponding to the lithium iron manganese phosphate composite material system battery with the best structural integrity is selected as the preset charging current of the lithium iron manganese phosphate composite material system battery under the preset conditions.

[0052] The method for determining the charging strategy of the power battery in the embodiment of the present application can determine a more suitable charging current, which is conducive to charging the power battery with the determined charging current. It can reduce the expansion stress and its change rate during the charging process, and reduce the mechanical impact on the battery microstructure, thereby achieving comprehensive optimization of multiple performance aspects of the battery, such as charging speed, cycle life, and safety risks.

[0053] Combination Figure 2 As shown, on the basis of the above embodiments, the method of the embodiments of the present application further includes: detecting the expansion force and voltage of each power battery during the charging process; generating characteristic curves of different rate currents with respect to the expansion force and voltage according to the detected expansion force and voltage, wherein the characteristic curve of the preset charging current with respect to the expansion force and voltage is a first characteristic curve, and the characteristic curves of the other rate currents with respect to the expansion force and voltage except the preset charging current are respectively a second characteristic curve; based on the charging speed and the expansion force, respectively comparing the first characteristic curve and each second characteristic curve in sections, and selecting the segmented charging current that meets the target principle in each section; combining the segmented charging currents of all the segments to generate a step charging current for the power battery under the preset conditions.

[0054] In this example, based on the charging speed and the expansion force, the first characteristic curve and each second characteristic curve are respectively compared in sections, and a sectioned charging current that meets the target principle is selected in each section, including: in each section comparison, all the second characteristic curves are grouped according to whether the curve trend is similar to the first characteristic curve, so as to obtain a first trend curve group with similar trends and a second trend curve group with different trends; the current with the highest rate among all the rate currents corresponding to the first trend curve group and the preset charging current is selected as the first characteristic current, and the current with the highest rate among all the rate currents corresponding to the second trend curve group is selected as the second characteristic current; the current with a low rate of change of expansion force between the first characteristic current and the second characteristic current is selected as the sectioned charging current of the section.

[0055] In the above example, before segmenting and comparing the first characteristic curve and each second characteristic curve based on the charging speed and the expansion force, for example, it includes: segmenting the first characteristic curve and the second characteristic curve according to the principle of equal division or using the intersection point between the first characteristic curve and the second characteristic curve as the segmentation point.

[0056] The characteristic curve is a first-order differential dP / dV curve, a first-order differential dP / dSOC curve or a second-order differential d2P / dV2 curve, wherein dP is the first-order differential of the expansion force of the lithium-ion battery, dV is the first-order differential of the voltage of the lithium-ion battery, and dSOC is the first-order differential of the capacity of the lithium-ion battery.

[0057] Specifically, the expansion force and voltage of different lithium iron manganese phosphate composite material system batteries during the charging process are detected in real time; based on the detected expansion force and voltage, characteristic curves of different rate currents with respect to expansion force and voltage are generated, a preset charging current corresponds to a first characteristic curve, and other rate currents other than the preset charging current respectively correspond to a second characteristic curve; the first characteristic curve and the second characteristic curve are divided and proportioned according to the principle of balancing charging speed and expansion force, a segmented charging current that meets the principle in each segment is selected, and the segmented charging currents of all segments are combined to generate a step charging current for the lithium iron manganese phosphate composite material system battery under the preset conditions.

[0058] The first characteristic curve and the second characteristic curve are compared in sections according to the principle of taking both charging speed and expansion force into consideration, and the segmented charging current that meets this principle is selected in each section, specifically including: in each section comparison, all the second characteristic curves are divided into two groups according to whether the curve trend is similar to the first characteristic curve, namely a first trend curve group with similar trends and a second trend curve group with dissimilar trends, wherein the similar trend means that the slope difference between the two compared characteristic curves is within a preset range; the current with the highest rate among all the rate currents corresponding to the first trend curve group and the preset charging current is selected as the first characteristic current; the current with the highest rate among all the rate currents corresponding to the second trend curve group is selected as the second characteristic current; the current with the lowest rate of change of expansion force in the first characteristic current and the second characteristic current is selected as the segment charging current of the section. Among them, the first characteristic curve and the second characteristic curve can be segmented according to the principle of equal division or the principle of using the intersection point between the first characteristic curve and the second characteristic curve as the segmentation point. Figure 3 As shown, a first-order differential dP / dV curve and a first-order differential dP / dSOC curve are shown.

[0059] After determining the preset charging current, when the power battery is charged with the preset charging current, when the battery voltage meets the full charge cut-off condition, the method further includes: starting timing when the battery voltage reaches the preset full charge cut-off voltage; when the timing reaches the preset time length, determining that the battery voltage meets the full charge cut-off condition based on the battery voltage still reaching the full charge cut-off voltage.

[0060] By using the condition that the battery voltage reaches the full charge cut-off voltage and lasts for a certain period of time as the end condition for charging using the maximum output current, the authenticity of the battery voltage reaching the full charge cut-off voltage can be ensured. In one embodiment of the present application, the multiple constant voltage charging according to the preset full charge cut-off voltage includes: determining the floating range of the battery voltage according to the full charge cut-off voltage; charging with the maximum output current of the charging device as the initial charging current of the constant voltage charging, and adjusting the charging current to gradually decrease according to the first battery state to maintain the battery voltage within the floating range to complete a constant voltage charge. Each constant voltage charge (CV) is performed by adaptively adjusting the large charging current to continuously decrease to maintain the battery voltage floating near the full charge cut-off voltage to charge a certain amount of electricity. After multiple constant voltage charging adjustments, the battery is charged with enough electricity. Compared with the charging strategy of the prior art that causes the battery to be not fully charged, the battery charging capacity can be effectively increased, the battery service life can be increased, and the battery expansion force can be optimized. Figure 4 As shown, it can be clearly seen that by adopting the method of the embodiment of the present application, the life and expansion force of the power battery are better optimized.

[0061] According to the method for determining the charging strategy of the power battery in the embodiment of the present application, a more suitable charging current can be determined, which is conducive to charging the power battery with the determined charging current. The expansion stress and its change rate during the charging process can be reduced, and the mechanical impact on the battery microstructure can be reduced, thereby achieving comprehensive optimization of multiple performance aspects of the battery, such as charging speed, cycle life, and safety risks.

[0062] Figure 5 is a structural block diagram of a system for determining a charging strategy for a power battery according to an embodiment of the present application. Figure 5 As shown, a charging strategy determination system for a power battery according to an embodiment of the present application includes: a charging and discharging control module 510, an evaluation module 520 and a determination module 530, wherein:

[0063] The charge and discharge control module 510 is used to perform charge and discharge operations on a plurality of power batteries of the same type under preset conditions, wherein the plurality of power batteries are charged using different rate currents;

[0064] An evaluation module 520, for evaluating the structural integrity of each power battery after multiple charge and discharge operations;

[0065] The determination module 530 is used to use the rate current corresponding to the power battery with the best structural completeness as the preset charging current of the power battery under the preset conditions.

[0066] According to the charging strategy determination system of the power battery in the embodiment of the present application, a more suitable charging current can be determined, which is conducive to charging the power battery with the determined charging current. The expansion stress and its change rate during the charging process can be reduced, and the mechanical impact on the battery microstructure can be reduced, thereby achieving comprehensive optimization of multiple performance aspects of the battery, such as charging speed, cycle life, and safety risks.

[0067] For the specific definition of the charging strategy determination system for the power battery, please refer to the definition of the charging strategy determination method for the power battery above, which will not be repeated here. The various modules of the above-mentioned charging strategy determination system for the power battery can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0068] Reference below Figure 6 , Figure 6 A schematic diagram of the structure of a computer device suitable for implementing the embodiments of the present application is shown.

[0069] like Figure 6As shown, computer system 1000 includes a central processing unit (CPU) 1001, 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 part 1008 into a random access memory (RAM) 1003. Various programs and data required for the operation instructions of the system are also stored in RAM 1003. CPU 1001, ROM 1002 and RAM 1003 are connected to each other via a bus 1004. An input / output (I / O) interface 1005 is also connected to bus 1004.

[0070] The following components are connected to the I / O interface 1005: an input section 1006 including a keyboard, a mouse, etc.; an output section 1007 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1008 including a hard disk, etc.; and a communication section 1009 including a network interface card such as a LAN card, a modem, etc. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to the I / O interface 1005 as needed. A removable medium 1011, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1010 as needed, so that a computer program read therefrom is installed into the storage section 1008 as needed.

[0071] In particular, according to an embodiment of the present application, the above reference flow chart Figure 1 The described process may be implemented as a computer-readable storage medium. For example, an embodiment of the present application includes a computer-readable storage medium, which includes a computer program, and the computer program includes a program code for executing the method shown in the flowchart.

[0072] In particular, according to an embodiment of the present application, the above reference flow chart Figure 1 The described process can be implemented as a computer software program. For example, a computer program product is included in an embodiment of the present application, which includes a computer program carried on a computer readable medium, and the computer program includes a program code for executing the method shown in the flow chart. In such an embodiment, the computer program includes a program code for executing the method shown in the flow chart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 1009, and / or installed from the removable medium 1011. When the computer program is executed by the central processing unit (CPU) 1001, the above-mentioned functions defined in the system of the present application are executed.

[0073] It should be noted that the computer-readable medium shown in the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium such as a computer-readable storage medium that can send, propagate or transmit a program for use by or in conjunction with an instruction execution system, device or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0074] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operating instructions of the system, method and computer program product according to various embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the aforementioned module, a program segment or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, the boxes represented by two connections can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operating instruction, or can be implemented with a combination of dedicated hardware and computer instructions.

[0075] The units or modules involved in the embodiments described in the present application may be implemented by software or hardware. The units or modules described may also be arranged in a processor. The names of these units or modules do not, in some cases, constitute limitations on the units or modules themselves.

[0076] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for determining a charging strategy for a power battery, characterized in that: include: Under preset conditions, charging and discharging operations are performed on a plurality of power batteries of the same type, wherein different rate currents are used for charging the plurality of power batteries; Evaluate the structural integrity of each power cell after multiple charge and discharge operations; The rate current corresponding to the power battery with the best structural completeness is used as the preset charging current of the power battery under the preset conditions.

2. The method for determining a charging strategy for a power battery according to claim 1, characterized in that: The assessment of the structural integrity of each power battery includes: Dismantle the power battery; Obtain microstructure characterization data of the pole piece of the disassembled power battery; The microstructural integrity of the pole piece is evaluated based on the microstructural characterization data of the pole piece of the power battery.

3. The method for determining a charging strategy for a power battery according to claim 2, characterized in that: The step of obtaining microstructure characterization data of the pole piece of the disassembled power battery includes: The microstructure of the pole piece of the disassembled power battery is characterized by using any one of a scanning electron microscope SEM, a transmission electron microscope TEM and a focused ion beam / scanning electron microscope FIB / SEM to obtain microstructure characterization data of the pole piece of the power battery.

4. The method for determining a charging strategy for a power battery according to any one of claims 1 to 3, characterized in that: Also includes: Detect the expansion force and voltage of each power battery during charging; Generate characteristic curves of different rate currents with respect to the expansion force and voltage according to the detected expansion force and voltage, wherein the characteristic curve of the preset charging current with respect to the expansion force and voltage is a first characteristic curve, and characteristic curves of other rate currents with respect to the expansion force and voltage except the preset charging current are respectively a second characteristic curve; Based on the charging speed and the expansion force, the first characteristic curve and each second characteristic curve are respectively compared in sections, and a section charging current that meets the target principle is selected in each section; The segmented charging currents of all the segments are combined to generate a step charging current for the power battery under the preset conditions.

5. The method for determining a charging strategy for a power battery according to claim 4, characterized in that: The first characteristic curve and each second characteristic curve are respectively compared in sections based on the charging speed and the expansion force, and a sectioned charging current that meets the target principle in each section is selected, including: In each comparison, all second characteristic curves are grouped according to whether the curve trend is similar to the first characteristic curve, so as to obtain a first trend curve group with similar trends and a second trend curve group with dissimilar trends; The current with the highest rate among all rate currents corresponding to the first trend curve group and the preset charging current is selected as the first characteristic current, and the current with the highest rate among all rate currents corresponding to the second trend curve group is selected as the second characteristic current; The current with the lowest rate of change of expansion force between the first characteristic current and the second characteristic current is selected as the segmented charging current for the segment.

6. The method for determining a charging strategy for a power battery according to claim 5, characterized in that: Before segmentally comparing the first characteristic curve and each second characteristic curve based on the charging speed and the expansion force, the method includes: The first characteristic curve and the second characteristic curve are segmented according to the principle of equal division or with the intersection point between the first characteristic curve and the second characteristic curve as the segmentation point.

7. The method for determining a charging strategy for a power battery according to claim 4, characterized in that: The characteristic curve is a first-order differential dP / dV curve, a first-order differential dP / dSOC curve or a second-order differential d2P / dV2 curve, wherein dP is the first-order differential of the expansion force of the lithium-ion battery, dV is the first-order differential of the voltage of the lithium-ion battery, and dSOC is the first-order differential of the capacity of the lithium-ion battery.

8. A system for determining a charging strategy for a power battery, characterized in that: include: A charge and discharge control module, used to perform charge and discharge operations on a plurality of power batteries of the same type under preset conditions, wherein the plurality of power batteries use different rate currents when being charged; An evaluation module for evaluating the structural integrity of each power battery after multiple charge and discharge operations; The determination module is used to use the rate current corresponding to the power battery with the best structural completeness as the preset charging current of the power battery under the preset conditions.

9. A computer 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 program, the method for determining the charging strategy of the power battery according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method for determining a charging strategy for a power battery according to any one of claims 1 to 7 is implemented.

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