WO2024065079A1 - Procédé et appareil de détermination de placage de lithium, ainsi que dispositif informatique, support de stockage et produit de programme - Google Patents

Procédé et appareil de détermination de placage de lithium, ainsi que dispositif informatique, support de stockage et produit de programme Download PDF

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WO2024065079A1
WO2024065079A1 PCT/CN2022/121256 CN2022121256W WO2024065079A1 WO 2024065079 A1 WO2024065079 A1 WO 2024065079A1 CN 2022121256 W CN2022121256 W CN 2022121256W WO 2024065079 A1 WO2024065079 A1 WO 2024065079A1
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battery
lithium deposition
ratio
preset threshold
cycle
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PCT/CN2022/121256
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English (en)
Chinese (zh)
Inventor
李茂华
耿慧慧
黄瑶
孔思宇
李伟
吴凯
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/121256 priority Critical patent/WO2024065079A1/fr
Publication of WO2024065079A1 publication Critical patent/WO2024065079A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging

Definitions

  • the present application relates to the field of battery technology, and in particular to a method, device, computer equipment, storage medium and program product for determining lithium plating.
  • lithium batteries are widely used in electric vehicles and electronic devices due to their advantages such as low pollution, high energy density, long cycle life and low self-discharge rate. Therefore, the safety of lithium batteries has received more and more attention, and lithium plating is an abnormal phenomenon in the application process of lithium batteries, which will damage the battery and reduce the safety of the battery. Therefore, how to determine whether lithium plating occurs in the battery has become a technical problem that needs to be solved urgently in this field.
  • the present application provides a method for determining lithium deposition.
  • the method comprises:
  • Whether lithium deposition occurs in the battery is determined based on the charging capacity and the discharging capacity.
  • the lithium plating determination method obtaineds the charging capacity of the nth cycle and the discharging capacity of the n+xth cycle of the battery, and determines whether the battery has lithium plating based on the charging capacity and the discharging capacity, thereby providing a solution for determining whether the battery has lithium plating, thereby avoiding damage to the battery due to lithium plating, which may reduce the safety of the battery.
  • determining whether lithium deposition occurs in the battery according to the charge capacity and the discharge capacity includes:
  • the span of the number of cycles between the charging capacity and the discharging capacity can be increased by increasing the span of the number of cycles between the charging capacity and the discharging capacity, and x can be taken as an integer greater than 0 to increase the span of the number of cycles between the charging capacity and the discharging capacity.
  • the ratio of Cn/D(n+x) is used to determine whether lithium deposition occurs in the battery, thereby avoiding errors and interference from the measuring environment and improving the sensitivity of lithium deposition detection.
  • determining whether lithium deposition occurs in the battery according to the ratio and a preset threshold value includes:
  • the ratio is greater than the preset threshold, it is determined that lithium deposition occurs in the battery.
  • determining whether lithium deposition occurs in the battery according to the ratio and a preset threshold value includes:
  • Whether lithium deposition occurs in the battery is determined based on the cycle test process, the ratio and the preset threshold.
  • determining whether lithium deposition occurs in the battery according to the cycle test process, the ratio and the preset threshold value includes:
  • cycle test process is a first test process
  • the ratio is greater than the preset threshold, it is determined that lithium deposition occurs in the battery; the charge and discharge modes of each cycle of the first test process are the same; and/or,
  • the charge and discharge capacity data in the cyclic test process are grouped according to a preset period, and whether lithium plating occurs in the battery is determined based on a ratio determined by the charge and discharge capacity data of each group and the preset threshold value; the charge and discharge capacity data in the cyclic test process include the charge capacity and discharge capacity of each circle, and the charge and discharge mode of at least one circle in the second test process is different from the charge and discharge modes of other circles.
  • a lithium deposition determination strategy matching the cycle test process is adopted, so as to ensure the accuracy of the lithium deposition determination.
  • determining whether lithium deposition occurs in the battery based on a ratio determined according to each group of charge and discharge capacity data and the preset threshold value includes:
  • At least one ratio corresponding to at least one set of the charge and discharge capacity data is greater than the preset threshold, it is determined that lithium deposition occurs in the battery.
  • determining whether lithium deposition occurs in the battery based on the ratios and a preset threshold value includes:
  • Whether lithium deposition occurs in the battery is determined based on the target ratio and the preset threshold.
  • the target ratio is obtained by eliminating abnormal ratios from multiple ratios, and whether lithium deposition occurs in the battery is determined based on the target ratio and a preset threshold value, thereby avoiding the interference of abnormal ratios and improving the accuracy of lithium deposition judgment.
  • determining whether lithium deposition occurs in the battery according to the target ratio and the preset threshold value includes:
  • determining whether lithium deposition occurs in the battery according to the plurality of target ratios and the preset threshold value includes:
  • a fitting curve is obtained by linearly fitting multiple target ratios. If the slope of the fitting curve is greater than a preset threshold value, it is determined that lithium deposition has occurred in the battery. Since linear fitting is performed on multiple target ratios, the target ratios include other ratios after eliminating abnormal ratios, thereby ensuring the accuracy of the data source on which the linear fitting is based, thereby improving the accuracy of the fitted curve and ensuring the accuracy of the battery lithium deposition determination result.
  • determining whether lithium deposition occurs in the battery according to the plurality of target ratios and the preset threshold value includes:
  • the target ratio includes other ratios after excluding abnormal ratios, so that the accuracy of the obtained average value can be guaranteed, and the accuracy of the battery lithium deposition determination result can be guaranteed.
  • determining whether lithium deposition occurs in the battery according to the target ratio and the preset threshold value includes:
  • the present application also provides a lithium precipitation determination device.
  • the device comprises:
  • An acquisition module used to acquire the charging capacity of the nth cycle and the discharging capacity of the n+xth cycle of the battery; wherein n is greater than or equal to 1, and x is greater than or equal to 0;
  • the determination module is used to determine whether lithium deposition occurs in the battery according to the charging capacity and the discharging capacity.
  • the determining module 1102 includes:
  • An acquisition submodule used for acquiring a ratio of the charging capacity to the discharging capacity
  • the determination submodule is used to determine whether lithium deposition occurs in the battery according to the ratio and a preset threshold value.
  • the determination submodule is specifically configured to determine that lithium deposition occurs in the battery if the ratio is greater than the preset threshold.
  • determining the submodule includes:
  • the first determination unit is used to determine whether lithium deposition occurs in the battery according to the cycle test process, the ratio and the preset threshold value.
  • the first determining unit includes:
  • a determination subunit for determining that lithium deposition occurs in the battery when the ratio is greater than the preset threshold if the cycle test process is a first test process; the charge and discharge modes of each cycle of the first test process are the same; and/or,
  • the grouping subunit is used to group the charge and discharge capacity data in the cycle test process according to a preset period if the cycle test process is the second test process; the determination subunit is also used to determine whether lithium deposition occurs in the battery according to a ratio determined by the charge and discharge capacity data of each group and the preset threshold value; the charge and discharge capacity data in the cycle test process include the charge capacity and discharge capacity of each cycle, and the charge and discharge mode of at least one cycle in the second test process is different from the charge and discharge modes of other cycles.
  • the determination subunit is specifically configured to determine that lithium deposition occurs in the battery if at least one ratio corresponding to at least one set of the charge and discharge capacity data is greater than the preset threshold.
  • determining the submodule includes:
  • a elimination unit is used to eliminate abnormal ratios from the multiple ratios to obtain a target ratio
  • the second determination unit is used to determine whether lithium deposition occurs in the battery according to the target ratio and the preset threshold value.
  • the second determination unit is specifically configured to determine whether lithium deposition occurs in the battery according to the multiple target ratios and the preset threshold value if multiple target ratios are obtained in the cycle test process of the battery.
  • the second determination unit is specifically configured to perform linear fitting on the multiple target ratios to obtain a fitting curve; if the slope of the fitting curve is greater than the preset threshold, it is determined that lithium deposition occurs in the battery.
  • the second determination unit is specifically used to determine an average value of a plurality of the target ratios; if the average value is greater than the preset threshold, it is determined that lithium deposition occurs in the battery.
  • the second determination unit is specifically configured to determine that lithium deposition occurs in the battery if a distribution of multiple target ratios in the target ratios is positively correlated with the number of cycles in the cycle test process of the battery.
  • the present application further provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method provided in the above embodiment when executing the computer program.
  • the present application further provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method provided in the above embodiment when executed by a processor.
  • the present application also provides a computer program product.
  • the computer program product includes a computer program, and when the computer program is executed by a processor, the steps of the method provided in the above embodiment are implemented.
  • the above-mentioned lithium plating determination method, device, computer equipment, storage medium and program product obtain the charging capacity of the nth cycle and the discharging capacity of the n+xth cycle of the battery, and determine whether the battery has lithium plating based on the charging capacity and the discharging capacity, thereby providing a solution for accurately determining whether the battery has lithium plating, thereby avoiding the problem of damage to the battery due to lithium plating, which leads to reduced battery safety.
  • FIG1 is a diagram showing the internal structure of a computer device in one embodiment
  • FIG2 is a schematic diagram of a flow chart of a lithium precipitation determination method provided in an embodiment of the present application.
  • FIG3 is a second flow chart of the method for determining lithium precipitation provided in an embodiment of the present application.
  • FIG4 is a schematic diagram of a result of lithium precipitation determination provided in an embodiment of the present application.
  • FIG5 is a third flow chart of the method for determining lithium precipitation provided in an embodiment of the present application.
  • FIG6 is a schematic diagram of discharge capacity results of a hybrid cycle test process provided in an embodiment of the present application.
  • FIG. 7 is a fourth flow chart of the method for determining lithium precipitation provided in an embodiment of the present application.
  • FIG8 is a fifth flow chart of the method for determining lithium precipitation provided in an embodiment of the present application.
  • FIG9 is a sixth flow chart of the method for determining lithium precipitation provided in an embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of a lithium deposition determination device provided in an embodiment of the present application.
  • Lithium deposition refers to the process in which, during the charging process of a lithium battery, when lithium ions extracted from the positive electrode cannot be embedded in the negative electrode, these lithium ions form metallic lithium on the surface of the negative electrode. Lithium deposition is an abnormal phenomenon in the application process of lithium batteries, which will damage the battery and reduce the safety of the battery. Therefore, how to determine whether lithium deposition occurs in a battery has become a technical problem that needs to be solved urgently in this field.
  • Cyclic capacity loss comes from power loss and irreversible capacity loss. Power loss exists during both charging and discharging, and mainly comes from the thickening of the passivation layer (solid electrolyte interface, SEI) on the surface of the positive and negative electrode materials. Irreversible capacity loss mainly comes from active lithium loss, including lithium plating and side reactions. Lithium plating occurs at the end of charging. During discharge, due to factors such as separation from conductive contact, the precipitated lithium cannot participate in discharge 100%, causing part of the lithium to be consumed, resulting in a decrease in discharge capacity. Obviously, lithium plating will cause the discharge capacity of the battery to be lower than the charging capacity. Side reactions are related to the state of charge (SOC) and exist during both charging and discharging.
  • SOC state of charge
  • lithium plating is related to the direction of charging and discharging. Therefore, it is possible to judge whether lithium plating occurs based on the charging capacity and discharge capacity of the same cycle or the charging capacity and discharge capacity of different cycles.
  • the embodiment of the present application provides a method for determining lithium precipitation.
  • the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
  • FIG. 1 is an internal structure diagram of a computer device in one embodiment, and the computer device can be a terminal, and its internal structure diagram can be shown in Figure 1.
  • the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected by a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities.
  • the memory of the computer device includes a non-volatile storage medium and an internal memory.
  • the non-volatile storage medium stores an operating system and a computer program.
  • the internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium.
  • the communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies.
  • WIFI wireless fidelity
  • NFC near field communication
  • the computer program is executed by the processor, a lithium precipitation determination method is implemented.
  • the display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen
  • the input device of the computer device can be a touch layer covered on the display screen, or a key, a trackball or a touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse.
  • FIG. 1 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied.
  • the specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.
  • FIG. 2 is a flow chart of a method for determining lithium deposition provided in an embodiment of the present application. The method is applied to a computer device as shown in FIG. 1 . The method comprises the following steps:
  • the cycle involved in the embodiment of the present application refers to the number of cycles of the battery cycle test, and one cycle of the cycle test includes one full charge of the battery and one full discharge of the battery.
  • the definition of the charging capacity and the discharging capacity in the embodiment of the present application can refer to the following description: one cycle of the battery full discharge-full charge is one cycle.
  • the first full discharge-full charge of the battery is recorded as the first full discharge-full charge, and the number of cycles is 1.
  • the charging capacity of the first full charge is the charging capacity of the first cycle
  • the discharging capacity of the first full discharge is the discharge capacity of the first cycle. After the battery performs the first full discharge-full charge, it then performs the second full discharge-full charge.
  • the discharge capacity of the second full discharge is the discharge capacity of the second cycle
  • the charging capacity of the second full charge is the charging capacity of the second cycle.
  • the number of cycles is 2.
  • the battery can be fully charged and fully discharged for n cycles.
  • the capacity after a certain cycle of full charge is the charging capacity of the cycle
  • the capacity after a certain cycle of full discharge is the discharge capacity of the cycle.
  • S202 Determine whether lithium deposition occurs in the battery according to the charging capacity and the discharging capacity.
  • whether lithium plating occurs can be determined based on the charging capacity and discharging capacity of the same cycle or the charging capacity and discharging capacity of different cycles.
  • Determining whether lithium deposition occurs based on the charge capacity and discharge capacity of the same cycle means that x in the above step S201 is equal to 0, so as to determine whether lithium deposition occurs in the battery based on the judgment result. For example, if Cn/Dn is greater than a first preset threshold, it is determined that lithium deposition occurs in the battery.
  • Cn represents the charge capacity of the nth cycle
  • Dn represents the discharge capacity of the nth cycle.
  • the charge capacity and discharge capacity of different cycles Judging whether lithium deposition occurs based on the charge capacity and discharge capacity of different cycles means that x in the above step S201 is greater than 0, so as to determine whether lithium deposition occurs in the battery based on the judgment result. For example, if Cn/D(n+x) is greater than the second preset threshold, it is determined that lithium deposition occurs in the battery. Wherein, D(n+x) represents the discharge capacity of the n+xth cycle.
  • the lithium plating determination method obtaineds the charging capacity of the nth cycle and the discharging capacity of the n+xth cycle of the battery, and determines whether the battery has lithium plating based on the charging capacity and the discharging capacity, thereby providing a solution for accurately determining whether the battery has lithium plating, thereby avoiding the problem of damage to the battery due to lithium plating, resulting in reduced battery safety.
  • FIG. 3 is a second flow chart of a method for determining lithium deposition provided in an embodiment of the present application.
  • This embodiment relates to a possible implementation method of determining whether lithium deposition occurs in a battery based on charging capacity and discharging capacity.
  • the above S202 may include:
  • S302 Determine whether lithium deposition occurs in the battery based on the ratio and a preset threshold.
  • the cycle span between the charging capacity and the discharging capacity can be increased by increasing the cycle span between the charging capacity and the discharging capacity, and x can be taken as an integer greater than 0 to increase the cycle span between the charging capacity and the discharging capacity, and the ratio of Cn/D(n+x) can be used to determine whether the battery has lithium deposition, thereby avoiding the error and the interference of the measuring environment and improving the sensitivity of lithium deposition detection.
  • x can be an integer greater than or equal to 5 and less than or equal to 10.
  • the value of x determines the sensitivity.
  • the value of x be an integer greater than or equal to 5 and less than or equal to 10. Under normal circumstances, x can be 5, so as to take into account both high sensitivity and the timeliness of lithium deposition determination.
  • Figure 4 is a schematic diagram of the results of lithium precipitation determination provided by an embodiment of the present application.
  • the ordinate C/D represents the ratio of charging capacity to discharging capacity.
  • Figure 4 shows the relationship curve 401, relationship curve 402 and relationship curve 403 between C/D and the number of cycles.
  • Relationship curve 401 is the relationship curve between Cn/Dn and the number of cycles
  • relationship curve 402 is the relationship curve between Cn/D(n+5) and the number of cycles
  • relationship curve 403 is the relationship curve between Cn/D(n+10) and the number of cycles.
  • the ratio of C/D includes Cn/Dn, Cn/D(n+5) and Cn/D(n+10).
  • Cn/D(n+5) and Cn/D(n+10) begin to show an increasing trend at the 80th cycle.
  • the disassembly results show that the battery has lithium deposition, which is consistent with the determination results of Cn/Dn+5 and Cn/Dn+10, that is, by increasing the cycle span between the charging capacity and the discharging capacity, the ratio of Cn/D(n+x) is used to determine whether the battery has lithium deposition, thereby improving the timeliness and accuracy of lithium deposition detection.
  • the disassembly result refers to the discovery of lithium deposition in the battery after disassembly.
  • the above S302 may be implemented as follows:
  • the ratio is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • Cn/D(n+5) shows an increasing trend at the 80th cycle, and the ratio of Cn/D(n+5) at the 80th cycle is greater than the preset threshold value, and it is determined that the battery has lithium deposition at the 80th cycle, that is, lithium deposition occurs when n is equal to 80.
  • Cn/D(n+10) shows an increasing trend at the 80th cycle, and the ratio of Cn/D(n+10) at the 80th cycle is greater than the preset threshold value, and it is determined that the battery has lithium deposition at the 80th cycle, that is, lithium deposition occurs when n is equal to 80.
  • the ratio of the charging capacity of the nth cycle of the battery to the discharge capacity of the n+xth cycle is greater than a preset threshold, it can be determined that the battery begins to undergo lithium deposition in the nth cycle, and the beginning of lithium deposition in the battery can be discovered in a timely manner, thereby improving the sensitivity of lithium deposition detection.
  • the above S302 determining whether lithium deposition occurs in the battery according to the ratio and the preset threshold value, can be implemented in the following manner:
  • the types of cycle test processes include ordinary type and mixed type.
  • Ordinary type means that the charge and discharge mode of each cycle of the cycle test process is the same, and mixed type means that the charge and discharge mode of at least one cycle in the cycle test process is different from the charge and discharge mode of other cycles.
  • the charge and discharge mode includes, for example, a step charge and discharge mode, a constant current charge and discharge mode, a constant voltage charge and discharge mode, etc.
  • the charge and discharge mode of each cycle is the same.
  • the cycle test process includes 200 cycles
  • the charge and discharge modes of the 200 cycles are the same, and the charge and discharge modes of the 200 cycles are the same means that the charging modes of the 200 cycles are the same and the discharging modes of the 200 cycles are the same.
  • the so-called 200-cycle charging mode is the same, and the 200-cycle discharging mode is the same, for example: the 200-cycle charging mode is a constant current charging mode, and the 200-cycle discharging mode can be a constant current discharging mode.
  • the 200-cycle charging mode is a constant current charging mode, and the 200-cycle discharging mode can be a step-type discharging mode.
  • the cycle test process is the first test process, it can be directly determined whether the battery has lithium deposition according to the ratio of Cn/D(n+x) and the preset threshold.
  • the first test process for example, refers to the above-mentioned common test process.
  • whether lithium deposition occurs in the battery is determined based on the cycle test process, ratio and preset threshold value, thereby ensuring the accuracy of the lithium deposition determination.
  • FIG. 5 is a third flow chart of a method for determining lithium deposition provided in an embodiment of the present application.
  • This embodiment relates to an optional implementation method of determining whether lithium deposition occurs in a battery based on a cycle test process, a ratio, and a preset threshold. Based on the above embodiment, the above determination of whether lithium deposition occurs in a battery based on a cycle test process, a ratio, and a preset threshold may include:
  • cycle test process is the first test process, when the ratio is greater than a preset threshold, it is determined that lithium deposition occurs in the battery; the charge and discharge modes of each cycle of the first test process are the same.
  • the cycle test process is the second test process
  • the charge and discharge capacity data in the cycle test process are grouped according to a preset period, and whether lithium plating occurs in the battery is determined based on a ratio determined by the charge and discharge capacity data of each group and a preset threshold value; the charge and discharge capacity data in the cycle test process include the charge capacity and discharge capacity of each circle, and the charge and discharge mode of at least one circle in the second test process is different from the charge and discharge modes of other circles.
  • the second test process for example, refers to the above-mentioned hybrid test process.
  • the preset cycle is equal to 5, and the first 4 cycles in the same preset cycle are step-type charging and constant current discharging, and the 5th cycle is constant current charging and discharging, and the cycle test is performed with the preset cycle, and the charge and discharge capacity data in the cycle test process are divided into 5 groups.
  • the first group of charge and discharge capacity data includes data of the 1st, 6th, 11th...cycles; the second group of charge and discharge capacity data includes data of the 2nd, 7th, 12th...cycles; the third group of charge and discharge capacity data includes data of the 3rd, 8th, 13th...cycles; the fourth group of charge and discharge capacity data includes data of the 4th, 9th, 13th...cycles; the fifth group of charge and discharge capacity data includes data of the 5th, 10th, 14th...cycles. Then, the Cn/D(n+x) of these 5 groups of data are calculated respectively. When the Cn/D(n+x) obtained in any group shows the characteristic signal of lithium deposition, it is determined that the battery is lithium deposited.
  • the value of x in Cn/D(n+x) can be flexibly selected according to the preset period. If the preset period is ⁇ 4, x can be a preset integer multiple of the preset period, and the preset integer is, for example, equal to 2 or 3; if the preset period is ⁇ 5, x can be equal to the preset period. For example, in the above example, if the preset period is equal to 5, then x can be equal to 5.
  • FIG 6 is a schematic diagram of the discharge capacity results of a hybrid cycle test process provided in an embodiment of the present application.
  • the hybrid cycle test process includes two charge and discharge modes, that is, the first 4 cycles in a preset cycle adopt the first charge and discharge mode and the 5th cycle adopts the second charge and discharge mode, the first charge and discharge mode can be step-type charging and constant current discharging, and the second charge and discharge mode can be constant current charging and constant current discharging.
  • a lithium deposition determination strategy matching the cycle test process is adopted, so as to ensure the accuracy of the lithium deposition determination.
  • the determination of whether lithium deposition occurs in the battery according to the ratio and the preset threshold value determined according to the charge and discharge capacity data of each group in S502 can be achieved in the following manner:
  • At least one ratio corresponding to at least one set of charge and discharge capacity data is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • the group of charge and discharge capacity data includes data of the 1st, 6th, 11th ... cycles.
  • the ratio of the charge capacity of the 1st cycle to the discharge capacity of the 6th cycle can be determined, and the ratio is recorded as ratio 1; the ratio of the charge capacity of the 6th cycle to the discharge capacity of the 11th cycle can be determined, and the ratio is recorded as ratio 2; the ratio of the charge capacity of the 11th cycle to the discharge capacity of the 16th cycle can be determined as ratio 3; the ratio of the charge capacity of the 16th cycle can be determined as ratio 4; the ratio of the charge capacity of the 16th cycle can be determined as ratio 5; the ratio of the charge capacity of the 16th cycle can be determined as ratio 6; the ratio of the discharge capacity of the 11th cycle can be determined as ratio 7; the ratio of the charge capacity of the 16th cycle can be determined as ratio 8; the ratio of the discharge capacity of the 16th cycle can be determined as ratio 9; the
  • ratio greater than the preset threshold value among the multiple ratios such as ratio 1, ratio 2, ratio 3, ratio 4, ratio 5, ratio 6, it is determined that the battery has lithium deposition.
  • ratio 3 is greater than the preset threshold value, it can be determined that the battery has lithium deposition.
  • At least one target ratio corresponding to at least one set of charge and discharge capacity data is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • the target ratio includes other ratios after excluding abnormal ratios from the ratios corresponding to a set of charge and discharge capacity data.
  • ratio 5 is determined to be an abnormal ratio, and ratio 5 is eliminated. If at least one of the remaining ratios after eliminating ratio 5 is greater than a preset threshold, it is determined that lithium deposition has occurred in the battery. For example, if ratio 7 is greater than the preset threshold, it is determined that lithium deposition has begun to occur in the battery.
  • At least one ratio corresponding to at least one set of charge and discharge capacity data is greater than a preset threshold, it is determined that lithium deposition has occurred in the battery. That is, as long as one ratio among the ratios corresponding to the multiple sets of charge and discharge capacity data is greater than the preset threshold, it can be determined that lithium deposition has occurred in the battery, thereby improving the efficiency of lithium deposition determination.
  • FIG. 7 is a fourth flow chart of a method for determining lithium deposition provided in an embodiment of the present application.
  • This embodiment relates to a possible implementation method of determining whether lithium deposition occurs in a battery based on a ratio and a preset threshold. Based on the above embodiment, the above S302 includes the following steps:
  • Cn/D(n+x) is used to calculate 10 ratios, namely C1/D6, C2/D7, C3/D8, C4/D9, C5/D10, C6/D11, C7/D12, C8/D13, C9/D14, and C10/D15. If the absolute value of the difference between the ratio determined by C4/D9 and the average value of the 10 ratios is greater than the preset difference, C4/D9 is determined to be an abnormal ratio, and the abnormal ratio is eliminated.
  • the obtained target ratio includes the other ratios among the 10 ratios except C4/D9.
  • S702 Determine whether lithium deposition occurs in the battery according to the target ratio and the preset threshold.
  • the target ratio is obtained by eliminating abnormal ratios from multiple ratios, and whether lithium deposition occurs in the battery is determined based on the target ratio and a preset threshold value, thereby avoiding the interference of abnormal ratios and improving the accuracy of lithium deposition judgment.
  • the above S702 determining whether lithium deposition occurs in the battery according to the target ratio and the preset threshold, can be implemented in the following manner:
  • FIG8 is a flowchart of the fifth method for determining lithium deposition provided in an embodiment of the present application. The method comprises the following steps:
  • multiple target ratios can be linearly fitted based on the least squares method to obtain a fitting curve.
  • the preset threshold is equal to 0.01. If the slope of the fitting curve exceeds 0.01, it is determined that lithium deposition occurs in the battery.
  • a fitting curve is obtained by linearly fitting multiple target ratios. If the slope of the fitting curve is greater than a preset threshold value, it is determined that lithium deposition has occurred in the battery. Since linear fitting is performed on multiple target ratios, the target ratios include other ratios after eliminating abnormal ratios, thereby ensuring the accuracy of the data source on which the linear fitting is based, thereby improving the accuracy of the fitted curve and ensuring the accuracy of the battery lithium deposition determination result.
  • FIG9 is a sixth flow chart of the method for determining lithium deposition provided in an embodiment of the present application. The method comprises the following steps:
  • the preset threshold is, for example, equal to 1.01. If the average value of the multiple target ratios is greater than 1.01, it is determined that lithium deposition occurs in the battery.
  • the target ratio includes other ratios after excluding abnormal ratios, so that the accuracy of the obtained average value can be guaranteed, and the accuracy of the battery lithium deposition determination result can be guaranteed.
  • the above S702 determining whether lithium deposition occurs in the battery according to the target ratio and the preset threshold, can be implemented in the following manner:
  • the distribution of multiple target ratios in the target ratio is positively correlated with the number of cycles in the battery cycle test process, that is, Cn/D(n+x) increases with the increase in the number of cycles, it can be determined that lithium deposition has occurred in the battery.
  • the lithium plating determination method described in the above embodiment can be applied to the determination of battery cycle lithium plating, and the battery lithium plating can be judged in time to assess the risk of the battery, stop the test in time and carry out failure analysis.
  • the determination results of the lithium plating determination method provided by the embodiment of the present application are introduced in conjunction with the following Table 1.
  • Table 1 below is the determination result of 12 cycle batteries. These 12 batteries come from different projects, and there are differences in test temperature and cycle test process. It can be seen from the determination results that Cn/D(n+5) and Cn/D(n+10) have high sensitivity and are consistent with the actual disassembly results. That is, the sensitivity is higher when x is not equal to 0, and the lithium plating determination is more accurate.
  • Cn/D(n+5) begins to increase at the 1800th lap
  • the determination result is lithium plating
  • the disassembly result is also lithium plating
  • Cn/D(n+10) begins to increase at the 260th lap
  • the disassembly result is also lithium plating. Therefore, when x is not equal to 0, the embodiment of the present application improves the sensitivity of lithium plating determination.
  • N in Table 1 represents normal, that is, the battery has no lithium deposition signal
  • a certain circle starts to increase, which means that a lithium deposition signal appears in a certain circle.
  • battery 4 Cn/Dn has no abnormal signal
  • Cn/Dn+5 and Cn/Dn+10 identify lithium deposition signals at 1800 circles.
  • the disassembly results show that the battery has lithium deposition, which is consistent with the judgment results of Cn/Dn+5 and Cn/Dn+10, reflecting the advantages of Cn/Dn+x.
  • the embodiment of the present application also provides a lithium deposition determination device for implementing the above-mentioned lithium deposition determination method.
  • the implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in one or more embodiments of the lithium deposition determination device provided below can refer to the limitations of the lithium deposition determination method above, and will not be repeated here.
  • FIG. 10 is a schematic diagram of the structure of a lithium precipitation determination device provided in an embodiment of the present application, and the device 1000 includes:
  • the acquisition module 1001 is used to acquire the charging capacity of the nth cycle and the discharging capacity of the n+xth cycle of the battery; wherein n is greater than or equal to 1, and x is greater than or equal to 0;
  • the determination module 1002 is used to determine whether lithium deposition occurs in the battery according to the charging capacity and the discharging capacity.
  • the determining module 1002 includes:
  • An acquisition submodule used to acquire the ratio of charging capacity to discharging capacity
  • the determination submodule is used to determine whether lithium deposition occurs in the battery based on the ratio and a preset threshold.
  • the determination submodule is specifically configured to determine that lithium deposition occurs in the battery if the ratio is greater than a preset threshold.
  • determining the submodule includes:
  • the first determination unit is used to determine whether lithium deposition occurs in the battery according to a cycle test process, a ratio and a preset threshold value.
  • the first determining unit includes:
  • a determination subunit is used to determine that lithium deposition occurs in the battery if the ratio is greater than a preset threshold value when the cycle test process is a first test process; the charge and discharge mode of each cycle of the first test process is the same;
  • a grouping subunit for grouping the charge and discharge capacity data in the cycle test process according to a preset period if the cycle test process is the second test process;
  • the determination subunit is also used to determine whether lithium deposition occurs in the battery according to a ratio determined by the charge and discharge capacity data of each group and a preset threshold value; the charge and discharge capacity data in the cycle test process include the charge capacity and discharge capacity of each circle, and the charge and discharge mode of at least one circle in the second test process is different from the charge and discharge modes of other circles.
  • the determination subunit is specifically configured to determine that lithium deposition occurs in the battery if at least one ratio corresponding to at least one set of charge and discharge capacity data is greater than a preset threshold.
  • determining the submodule includes:
  • a elimination unit used for eliminating abnormal ratios from multiple ratios to obtain a target ratio
  • the second determination unit is used to determine whether lithium deposition occurs in the battery according to the target ratio and a preset threshold value.
  • the second determination unit is specifically configured to determine whether lithium deposition occurs in the battery according to the multiple target ratios and a preset threshold value if multiple target ratios are obtained in a cycle test process of the battery.
  • the second determination unit is specifically used to perform linear fitting on multiple target ratios to obtain a fitting curve; if the slope of the fitting curve is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • the second determination unit is specifically used to determine an average value of a plurality of target ratios; if the average value is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • the second determination unit is specifically configured to determine that lithium deposition occurs in the battery if a distribution of multiple target ratios in the target ratios is positively correlated with the number of cycles in a cycle test process of the battery.
  • Each module in the above-mentioned lithium precipitation determination device can be implemented in whole or in part by software, hardware and a combination thereof.
  • Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.
  • a computer device including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:
  • n is greater than or equal to 1
  • x is greater than or equal to 0
  • the ratio is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • cycle test process is the first test process, when the ratio is greater than the preset threshold, it is determined that lithium deposition occurs in the battery; the charge and discharge mode of each cycle of the first test process is the same;
  • the charge and discharge capacity data in the cyclic test process are grouped according to a preset period, and whether lithium plating occurs in the battery is determined based on a ratio determined by the charge and discharge capacity data of each group and a preset threshold value; the charge and discharge capacity data in the cyclic test process include the charge capacity and discharge capacity of each circle, and the charge and discharge mode of at least one circle in the second test process is different from the charge and discharge modes of other circles.
  • At least one ratio corresponding to at least one set of charge and discharge capacity data is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • a computer readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:
  • n is greater than or equal to 1
  • x is greater than or equal to 0
  • the ratio is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • cycle test process is the first test process, when the ratio is greater than the preset threshold, it is determined that lithium deposition occurs in the battery; the charge and discharge mode of each cycle of the first test process is the same;
  • the charge and discharge capacity data in the cyclic test process are grouped according to a preset period, and whether lithium deposition occurs in the battery is determined based on a ratio and a preset threshold determined by the charge and discharge capacity data of each group; the charge and discharge capacity data in the cyclic test process include the charge capacity and discharge capacity of each circle, and the charge and discharge mode of at least one circle in the second test process is different from the charge and discharge modes of other circles.
  • At least one ratio corresponding to at least one set of charge and discharge capacity data is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • a computer program product comprising a computer program, which, when executed by a processor, implements the following steps:
  • n is greater than or equal to 1
  • x is greater than or equal to 0
  • the ratio is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • cycle test process is the first test process, when the ratio is greater than the preset threshold, it is determined that lithium deposition occurs in the battery; the charge and discharge mode of each cycle of the first test process is the same;
  • the charge and discharge capacity data in the cyclic test process are grouped according to a preset period, and whether lithium plating occurs in the battery is determined based on a ratio determined by the charge and discharge capacity data of each group and a preset threshold value; the charge and discharge capacity data in the cyclic test process include the charge capacity and discharge capacity of each circle, and the charge and discharge mode of at least one circle in the second test process is different from the charge and discharge modes of other circles.
  • At least one ratio corresponding to at least one set of charge and discharge capacity data is greater than a preset threshold, it is determined that lithium deposition occurs in the battery.
  • user information including but not limited to user device information, user personal information, etc.
  • data including but not limited to data used for analysis, stored data, displayed data, etc.
  • any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory.
  • Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc.
  • Volatile memory can include random access memory (RAM) or external cache memory, etc.
  • RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).
  • SRAM static random access memory
  • DRAM dynamic random access memory
  • the database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database.
  • Non-relational databases may include distributed databases based on blockchain, etc., but are not limited to this.
  • the processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, etc., but are not limited to this.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Secondary Cells (AREA)

Abstract

La présente demande se rapporte à un procédé et à un appareil de détermination de placage de lithium, ainsi qu'à un dispositif informatique, à un support de stockage et à un produit de programme. Le procédé consiste : à acquérir une capacité de charge de nième cycle et une capacité de décharge de (n+x)ième cycle d'une batterie et à déterminer, en fonction de la capacité de charge et de la capacité de décharge, si un placage de lithium se produit dans la batterie. Une solution pour déterminer avec précision si un placage de lithium se produit dans une batterie est fournie, ce qui permet d'éviter le problème de sécurité réduite d'une batterie due à un endommagement de la batterie provoqué par le placage de lithium.
PCT/CN2022/121256 2022-09-26 2022-09-26 Procédé et appareil de détermination de placage de lithium, ainsi que dispositif informatique, support de stockage et produit de programme WO2024065079A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108845262A (zh) * 2018-04-28 2018-11-20 北京新能源汽车股份有限公司 一种电池析锂的检测方法、装置及测试设备
WO2021056687A1 (fr) * 2019-09-29 2021-04-01 宁德新能源科技有限公司 Procédé de charge, dispositif électronique et support de stockage
CN112782599A (zh) * 2020-12-28 2021-05-11 清华大学 锂离子电池无损析锂检测方法、装置及计算机设备
CN114487855A (zh) * 2022-02-11 2022-05-13 阳光储能技术有限公司 电池的析锂检测方法、装置、存储介质以及处理器
CN115097325A (zh) * 2022-06-30 2022-09-23 重庆金康赛力斯新能源汽车设计院有限公司 一种电池检测方法、装置、设备及存储介质

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108845262A (zh) * 2018-04-28 2018-11-20 北京新能源汽车股份有限公司 一种电池析锂的检测方法、装置及测试设备
WO2021056687A1 (fr) * 2019-09-29 2021-04-01 宁德新能源科技有限公司 Procédé de charge, dispositif électronique et support de stockage
CN112782599A (zh) * 2020-12-28 2021-05-11 清华大学 锂离子电池无损析锂检测方法、装置及计算机设备
CN114487855A (zh) * 2022-02-11 2022-05-13 阳光储能技术有限公司 电池的析锂检测方法、装置、存储介质以及处理器
CN115097325A (zh) * 2022-06-30 2022-09-23 重庆金康赛力斯新能源汽车设计院有限公司 一种电池检测方法、装置、设备及存储介质

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