Capacity compensation method of lithium ion battery, electronic equipment, driving equipment and medium

Abstract

The invention relates to the field of batteries, particularly provides a capacity compensation method of a lithium ion battery, electronic equipment, driving equipment and a medium, and aims to solve the problem of how to improve the energy density and the cycle life of the lithium ion battery. The lithium ion battery comprises a first material, the first material is a capacity compensation material, and the method comprises the following steps: S1, charging the lithium ion battery for the first time based on a first condition; s2, performing conventional charge-discharge circulation on the lithium ion battery to obtain the capacity fading rate of the lithium ion battery; s3, when the capacity fading rate exceeds a preset threshold value, carrying out capacity compensation on the lithium ion battery based on a second condition; s4, repeatedly executing the steps S2-S3 until the accumulated compensation capacity reaches the maximum compensation capacity of the first material; wherein the first condition comprises a first voltage, the second condition comprises a second voltage, and the first voltage is smaller than the second voltage. By means of the implementation mode, the long cycle life can be guaranteed while high energy density is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a capacity compensation method for a lithium-ion battery, an electronic device, a driving device, and a medium. Background Art

[0002] Due to its outstanding advantages such as high energy density, long cycle life, and high energy conversion efficiency, the lithium-ion battery has become the mainstream battery for portable consumer digital products such as mobile phones, cameras, and laptop computers, and is also widely used in fields such as electric vehicles, artificial intelligence, two-wheel vehicles, drones, smart grids, and home energy storage.

[0003] In recent years, with the continuous increase in the demand for products such as portable consumer electronic products and electric vehicles, the market has also put forward higher requirements for the energy density and cycle life of lithium-ion batteries. In addition, during the use of lithium-ion batteries, especially in the early stage of use, capacity attenuation is likely to occur, affecting the energy density and cycle life of the batteries.

[0004] Correspondingly, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0005] In order to overcome the above defects, the present application is proposed to provide a capacity compensation method for a lithium-ion battery, an electronic device, a driving device, and a medium that solve or at least partially solve the technical problem of how to improve the energy density and cycle life of a lithium-ion battery.

[0006] In a first aspect, a capacity compensation method for a lithium-ion battery is provided. The lithium-ion battery includes a first material, and the first material is a capacity compensation material. The method includes:

[0007] S1. Perform a first charge on the lithium-ion battery based on a first condition;

[0008] S2. Obtain the capacity attenuation rate of the lithium-ion battery by performing a conventional charge and discharge cycle on the lithium-ion battery;

[0009] S3. When the capacity attenuation rate exceeds a preset threshold, perform capacity compensation on the lithium-ion battery based on a second condition;

[0010] S4. Repeat S2 - S3 until the cumulative compensation capacity reaches the maximum compensation capacity of the first material;

[0011] Wherein, the first condition includes a first voltage, the second condition includes a second voltage, and the first voltage is less than the second voltage.

[0012] In one technical solution of the above-mentioned capacity compensation method for a lithium-ion battery, the first condition further includes a first compensation capacity, and the second condition further includes a second compensation capacity; the method further includes:

[0013] Based on the relationship between the compensation capacity and the compensation voltage of the first material, obtain the first voltage corresponding to the first compensation capacity and the second voltage corresponding to the second compensation capacity.

[0014] In one technical solution of the above-mentioned capacity compensation method for a lithium-ion battery, the first condition further includes a first temperature, and the second condition further includes a second temperature; the method further includes:

[0015] Based on the relationship between the compensation capacity and the compensation voltage of the first material at a preset compensation temperature, obtain the first voltage corresponding to the first compensation capacity at the first temperature and the second voltage corresponding to the second compensation capacity at the second temperature.

[0016] In one technical solution of the above-mentioned capacity compensation method for a lithium-ion battery, the first charging of the lithium-ion battery based on the first condition includes:

[0017] At the first temperature, perform the first charging of the lithium-ion battery based on the first voltage;

[0018] And / or, the capacity compensation of the lithium-ion battery based on the second condition includes:

[0019] At the second temperature, perform the capacity compensation of the lithium-ion battery based on the second voltage.

[0020] In one technical solution of the above-mentioned capacity compensation method for a lithium-ion battery, the first material is added to the positive electrode material of the lithium-ion battery, and the method further includes:

[0021] Based on the mass of the first material, the gram capacity of the positive electrode material of the lithium-ion battery, the irreversible gram capacity of the first material, and the compensation efficiency of the first material, obtain the maximum compensation capacity of the first material;

[0022] Wherein, the compensation efficiency of the first material is the ratio of the theoretical compensation capacity to the actual compensation capacity of the first material.

[0023] In one technical solution of the above-mentioned capacity compensation method for a lithium-ion battery, the method further includes:

[0024] Obtain the first compensation capacity and the second compensation capacity;

[0025] Wherein, the first compensation capacity accounts for 20%-50% of the maximum compensation capacity.

[0026] In a technical solution of the above capacity compensation method for a lithium-ion battery, the second condition further includes a third voltage and a fourth voltage, and the third voltage is less than the fourth voltage; when the capacity attenuation rate exceeds a preset threshold, performing capacity compensation on the lithium-ion battery based on the second condition includes:

[0027] When the capacity attenuation rate exceeds the preset threshold, performing a second capacity compensation on the lithium-ion battery based on the third voltage;

[0028] After the second capacity compensation, when the capacity attenuation rate exceeds the preset threshold, performing a third capacity compensation on the lithium-ion battery based on the fourth voltage.

[0029] In a technical solution of the above capacity compensation method for a lithium-ion battery, the preset threshold includes a first threshold and a second threshold, and the first threshold is less than the second threshold; when the capacity attenuation rate exceeds the preset threshold, performing capacity compensation on the lithium-ion battery based on the second condition further includes:

[0030] When the capacity attenuation rate exceeds the first threshold, performing the second capacity compensation on the lithium-ion battery based on the third voltage;

[0031] After the second capacity compensation, when the capacity attenuation rate exceeds the second threshold, performing the third capacity compensation on the lithium-ion battery based on the fourth voltage.

[0032] In a second aspect, there is provided an electronic device, which includes a processor and a storage device. The storage device is adapted to store multiple program codes, and the program codes are adapted to be loaded and run by the processor to execute the capacity compensation method for a lithium-ion battery according to any one of the technical solutions in the above technical solutions of the capacity compensation method for a lithium-ion battery.

[0033] In a third aspect, there is provided a driving device, which includes a driving device body and the electronic device according to the technical solution of the above electronic device.

[0034] In a fourth aspect, there is provided a computer-readable storage medium, which stores multiple program codes therein, and the program codes are adapted to be loaded and run by a processor to execute the capacity compensation method for a lithium-ion battery according to any one of the technical solutions in the above technical solutions of the capacity compensation method for a lithium-ion battery.

[0035] Solution 1. A capacity compensation method for a lithium-ion battery, characterized in that the lithium-ion battery includes a first material, and the first material is a capacity compensation material, and the method includes:

[0036] S1. Charge the lithium-ion battery for the first time based on the first condition;

[0037] S2. Obtain the capacity attenuation rate of the lithium-ion battery by performing regular charge and discharge cycles on the lithium-ion battery;

[0038] S3. When the capacity attenuation rate exceeds a preset threshold, perform capacity compensation on the lithium-ion battery based on the second condition;

[0039] S4. Repeat S2 - S3 until the cumulative compensation capacity reaches the maximum compensation capacity of the first material;

[0040] Wherein, the first condition includes a first voltage, the second condition includes a second voltage, and the first voltage is less than the second voltage.

[0041] Solution 2. The capacity compensation method for a lithium-ion battery according to Solution 1, characterized in that the first condition further includes a first compensation capacity, and the second condition further includes a second compensation capacity; the method further includes:

[0042] Based on the relationship between the compensation capacity and the compensation voltage of the first material, obtain the first voltage corresponding to the first compensation capacity and the second voltage corresponding to the second compensation capacity.

[0043] Solution 3. The capacity compensation method for a lithium-ion battery according to Solution 2, characterized in that the first condition further includes a first temperature, and the second condition further includes a second temperature; the method further includes:

[0044] Based on the relationship between the compensation capacity and the compensation voltage of the first material at a preset compensation temperature, obtain the first voltage corresponding to the first compensation capacity at the first temperature and the second voltage corresponding to the second compensation capacity at the second temperature.

[0045] Solution 4. The capacity compensation method for a lithium-ion battery according to Solution 3, characterized in that the charging the lithium-ion battery for the first time based on the first condition includes:

[0046] At the first temperature, perform the first charging on the lithium-ion battery based on the first voltage;

[0047] And / or, the performing capacity compensation on the lithium-ion battery based on the second condition includes:

[0048] At the second temperature, perform the capacity compensation on the lithium-ion battery based on the second voltage.

[0049] Solution 5. The capacity compensation method for a lithium-ion battery according to Solution 2, characterized in that the first material is added to the positive electrode material of the lithium-ion battery, and the method further includes:

[0050] Based on the mass of the first material, the specific capacity of the positive electrode material of the lithium-ion battery, the irreversible specific capacity of the first material, and the compensation efficiency of the first material, obtain the maximum compensation capacity of the first material;

[0051] Wherein, the compensation efficiency of the first material is the ratio of the theoretical compensation capacity of the first material to the actual compensation capacity.

[0052] Solution 6. The capacity compensation method for a lithium-ion battery according to Solution 5, characterized in that the method further includes:

[0053] Obtain the first compensation capacity and the second compensation capacity;

[0054] Wherein, the first compensation capacity accounts for 20%-50% of the maximum compensation capacity.

[0055] Solution 7. The capacity compensation method for a lithium-ion battery according to Solution 1, characterized in that the second condition further includes a third voltage and a fourth voltage, and the third voltage is less than the fourth voltage; when the capacity attenuation rate exceeds a preset threshold, performing capacity compensation on the lithium-ion battery based on the second condition includes:

[0056] When the capacity attenuation rate exceeds the preset threshold, perform a second capacity compensation on the lithium-ion battery based on the third voltage;

[0057] After the second capacity compensation, when the capacity attenuation rate exceeds the preset threshold, perform a third capacity compensation on the lithium-ion battery based on the fourth voltage.

[0058] Solution 8. The capacity compensation method for a lithium-ion battery according to Solution 7, characterized in that the preset threshold includes a first threshold and a second threshold, and the first threshold is less than the second threshold; when the capacity attenuation rate exceeds the preset threshold, performing capacity compensation on the lithium-ion battery based on the second condition further includes:

[0059] When the capacity attenuation rate exceeds the first threshold, perform the second capacity compensation on the lithium-ion battery based on the third voltage;

[0060] After the second capacity compensation, when the capacity attenuation rate exceeds the second threshold, perform the third capacity compensation on the lithium-ion battery based on the fourth voltage.

[0061] Solution 9. An electronic device includes a processor and a storage device. The storage device is adapted to store multiple program codes. It is characterized in that the program codes are adapted to be loaded and run by the processor to execute the capacity compensation method of the lithium-ion battery according to any one of Solutions 1 to 8.

[0062] Solution 10. A driving device is characterized in that the driving device includes a driving device body and the electronic device according to Solution 9.

[0063] Solution 11. A computer-readable storage medium stores multiple program codes. It is characterized in that the program codes are adapted to be loaded and run by a processor to execute the capacity compensation method of the lithium-ion battery according to any one of Solutions 1 to 8.

[0064] One or more of the above technical solutions of the present application have at least one or more of the following Beneficial effects:

[0065] In implementing the technical solution of the present application, the lithium-ion battery includes a first material, and the first material is a capacity compensation material. The method includes: S1. Perform the first charge on the lithium-ion battery based on a first condition; S2. Obtain the capacity attenuation rate of the lithium-ion battery by performing regular charge and discharge cycles on the lithium-ion battery; S3. When the capacity attenuation rate exceeds a preset threshold, perform capacity compensation on the lithium-ion battery based on a second condition; S4. Repeat S2 - S3 until the cumulative compensation capacity reaches the maximum compensation capacity of the first material; wherein, the first condition includes a first voltage, the second condition includes a second voltage, and the first voltage is less than the second voltage. Through the above implementation manner, capacity compensation is performed during the first charge, which can improve the first charge and discharge efficiency of the battery and avoid the risk of lithium deposition on the negative electrode during the first charge. During subsequent charge and discharge processes, compensation is triggered according to the capacity attenuation situation, which can continuously compensate for the loss of active lithium ions to a certain extent during the cycle, and avoid the problem of low energy density caused by the inability to utilize the excessive negative electrode active material used for the first lithium compensation during subsequent cycle processes, while ensuring high energy density and long cycle life. Description of the Drawings

[0066] Referring to the accompanying drawings, the disclosure of the present application will become more understandable. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the protection scope of the present application. Among them:

[0067] Figure 1 is a schematic diagram of the main step flow of the capacity compensation method of the lithium-ion battery according to an embodiment of the present application;

[0068] Figure 2Schematic diagram of the main steps for capacity compensation of a lithium-ion battery based on a second condition according to an embodiment of the present application;

[0069] Figure 3 Schematic diagram of the main steps for capacity compensation of a lithium-ion battery based on a second condition according to another embodiment of the present application;

[0070] Figure 4 Schematic diagram of the main structure of an electronic device according to an embodiment of the present application.

[0071] List of reference numerals:

[0072] 401: Processor; 402: Storage device. Detailed implementation manners

[0073] Some implementation manners of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present application and are not intended to limit the protection scope of the present application.

[0074] In the description of the present application, a "processor" may include hardware, software, or a combination of both. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, in hardware, or in a combination of both. A non-transitory computer-readable storage medium includes any suitable medium for storing program code, such as a magnetic disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, and so on. The term "A and / or B" represents all possible combinations of A and B, such as only A, only B, or A and B. The term "at least one A or B" or "at least one of A and B" has a meaning similar to "A and / or B" and may include only A, only B, or A and B. The singular terms "a" and "this" may also include the plural form.

[0075] As described in the background art, due to its outstanding advantages such as high energy density, long cycle life, and high energy conversion efficiency, lithium-ion batteries have become the mainstream batteries for portable consumer digital products such as mobile phones, cameras, and laptop computers, and are also widely used in fields such as electric vehicles, artificial intelligence, two-wheel vehicles, drones, smart grids, and home energy storage.

[0076] In recent years, with the continuous increase in the demand for products such as portable consumer electronic products and electric vehicles, the market has also put forward higher requirements for the energy density and cycle life of lithium-ion batteries.

[0077] In addition, during the first charging process of a lithium-ion battery, the components in the electrolyte will be reduced and decomposed on the surface of the negative electrode material to form a solid electrolyte interface film (SEI). This process will consume a part of the lithium ions that have escaped from the positive electrode material, resulting in the loss of active lithium. Subsequently, as the number of charge-discharge cycles increases, the number of active lithium ions in the electrode material will gradually decrease, thereby affecting the energy density and cycle life of the battery.

[0078] To solve the above problems, the present application provides a capacity compensation method, an electronic device, a driving device, and a medium for a lithium-ion battery.

[0079] Refer to the attached Figure 1 , Figure 1 It is a schematic diagram of the main steps of the capacity compensation method for a lithium-ion battery according to an embodiment of the present application. Among them, the lithium-ion battery includes a first material, and the first material is a capacity compensation material. As Figure 1 shown, the capacity compensation method for the lithium-ion battery in the embodiment of the present application mainly includes the following steps S101 to S104.

[0080] Step S101: Perform the first charge on the lithium-ion battery based on the first condition;

[0081] Step S102: Obtain the capacity attenuation rate of the lithium-ion battery by performing conventional charge-discharge cycles on the lithium-ion battery;

[0082] Step S103: When the capacity attenuation rate exceeds the preset threshold, perform capacity compensation on the lithium-ion battery based on the second condition;

[0083] Step S104: Repeat steps S102 to S103 until the cumulative compensation capacity reaches the maximum compensation capacity of the first material;

[0084] Among them, the first condition includes a first voltage, the second condition includes a second voltage, and the first voltage is less than the second voltage.

[0085] Based on the method described in steps S101 to S104 above, performing capacity compensation during the first charge can improve the first charge-discharge efficiency of the battery and avoid the risk of lithium deposition on the negative electrode during the first charge. During subsequent charge-discharge processes, compensation is triggered according to the capacity attenuation situation, which can continuously compensate for the lost active lithium ions to a certain extent during the cycle, and avoid the problem of low energy density caused by the inability to utilize the excessive negative electrode active material used for the first lithium compensation in subsequent cycles. While ensuring a high energy density, a long cycle life is guaranteed.

[0086] The following further explains the above steps S101 to S104.

[0087] In some embodiments, a first material, which is a capacity compensation material, can be added to the positive electrode material of a lithium-ion battery.

[0088] Among them, the positive electrode material of the lithium-ion battery can be an olivine-type material, which refers to a material based on the olivine structure. Olivine-type materials have advantages such as high electrochemical stability, good cycle life, and high energy density, and mainly include one or more of lithium iron phosphate, lithium vanadium phosphate and its modified materials, lithium manganese iron phosphate and its modified materials, lithium manganese phosphate and its modified materials, lithium iron silicate and its modified materials, and lithium manganese iron silicate and its modified materials.

[0089] The first material can be selected from LiF, Li2S, Li2O, Li2O2, Li2NiO2, Li2C3O5, Li2C4O4, Li5FeO4, Li2CuO2, Li2CuNiO2, Li3N, Li6CoO4, Li+aX b O C (wherein, the X element is selected from one of Mn, Mo, Ru, Ti, Zr, Mg, Zn, Ba, B, Ni, Co, 0.05≤a≤0.5, 0.10<b≤0.95, 2≤c<4), etc., one or more of the lithium-rich materials.

[0090] Furthermore, when adding the first material to the positive electrode material of the lithium-ion battery, if the addition of the first material is too little, the improvement effect on the lithium-ion battery is poor; if the addition is too much, the energy density and safety performance of the lithium-ion battery will be reduced. Therefore, an appropriate amount of the first material needs to be selectively added according to the battery capacity.

[0091] In some embodiments, in order to take into account the cycle life, energy density, safety performance, and manufacturing cost of the battery at the same time, the maximum compensation capacity of the added first material can be 1%-30% of the battery capacity, and preferably, it can be 1%-13%.

[0092] Among them, the maximum compensation capacity of the first material can be calculated based on the mass of the first material, the specific capacity of the positive electrode material of the lithium-ion battery, the irreversible specific capacity of the first material, and the compensation efficiency of the first material.

[0093] Specifically, the maximum compensation capacity of the first material Among them, K is the compensation efficiency of the first material, K≤1; a is the specific capacity of the positive electrode material of the lithium-ion battery; b is the irreversible specific capacity of the first material; w is the mass ratio of the first material in the positive electrode material.

[0094] Among them, the gram capacity a of the positive electrode material of the lithium-ion battery is the ratio of the capacity that the positive electrode material can release to the mass of the positive electrode material; the irreversible gram capacity b of the first material is the ratio of the capacity of lithium ions in the first material that cannot be completely reversibly released to the mass of the first material; the compensation efficiency K of the first material is the ratio of the theoretical compensation capacity of the first material to the actual compensation capacity. The above values ​​a, b, K, and w can all be obtained by testing lithium-ion batteries.

[0095] It should be pointed out that the above examples of positive electrode materials, first materials and the amount of the first material added for lithium-ion batteries are only schematic illustrations. In practical applications, those skilled in the art can select appropriate first materials to add according to specific needs, and no limitation is made here.

[0096] In some implementations of the above step S101, the first condition is a preset compensation condition for capacity compensation of the lithium-ion battery when it is charged for the first time. Specifically, the first condition may include a preset first voltage, a first compensation capacity, a first temperature, a first charging current, and a first discharging current.

[0097] Among them, the first voltage can be 3.7-4.5V; the first compensation capacity can account for 20%-50% of the maximum compensation capacity; the first temperature can be a high temperature range, specifically 40-70°C; the first charging current can be 0-10C, and the first discharging current can be 0-20C.

[0098] Furthermore, in some implementations of the above step S101, a first compensation capacity may be obtained, and compensation may be performed when the lithium-ion battery is charged for the first time.

[0099] At present, some schemes activate and release the first material all at once during the first charge. The lithium-rich material will release a large amount of active lithium during the first cycle, which requires an excess of negative electrode active material to provide embedding sites for active lithium. In addition, due to the low initial coulombic efficiency, this part of the excess negative electrode active material cannot participate in the lithium deintercalation process in the later cycle, resulting in a decrease in the energy density of the secondary battery. In addition, high-voltage charging is usually required to replenish lithium in secondary batteries during battery formation or initial charging, which also causes a series of problems such as phase change of materials on the surface of the positive and negative pole pieces, decomposition and gas production of the electrolyte, and large DC resistance DCR. These problems will become more serious with the cycle.

[0100] Therefore, in some embodiments of the present application, the capacity loss of the first charge can be determined according to the characteristics of different lithium-ion batteries, such as the composition of battery materials, preparation process, usage conditions, etc., and the first compensation capacity of the first charge can be pre-set.

[0101] For example, the first compensation capacity is set to 1%-5% of the battery capacity, or 20%-50% of the maximum capacity compensation amount of the first material, etc., which is not limited here.

[0102] Further, after obtaining the first compensation capacity, the first voltage corresponding to the first compensation capacity can be obtained based on the relationship between the compensation capacity and the compensation voltage of the first material.

[0103] Specifically, based on the relationship between the compensation capacity and the compensation voltage of the first material at a preset compensation temperature, the first voltage corresponding to the first compensation capacity at the first temperature can be obtained.

[0104] Since a part of the lithium ions released from the positive electrode material will be consumed during the first charge of the lithium-ion battery, resulting in capacity attenuation and affecting the energy density and cycle life of the battery, the battery can be heated to the first temperature during the first charge. The first temperature is selected from the high-temperature range, for example, 40-70°C, and capacity compensation is performed on the battery based on this temperature.

[0105] High temperature can reduce the energy barrier caused by battery polarization during the lithium compensation process, enable more active lithium to be released by the lithium compensation material under the same preset compensation voltage, promote the diffusion rate of lithium ions in the electrolyte at the same time, accelerate the movement speed of lithium ions, and improve the lithium compensation rate.

[0106] Among them, for different lithium-ion batteries at different temperatures, the relationship between their compensation capacity and compensation voltage is different. And the compensation capacity is related to the corresponding compensation voltage and temperature.

[0107] In order to obtain the first voltage corresponding to the first compensation capacity at the first temperature, the relationship between the compensation capacity and the compensation voltage of the first material at a preset compensation temperature can be obtained first.

[0108] In some embodiments, tests and studies can be carried out through experiments to obtain the compensation voltages V0-V100 (V0-V100∈2.0-4.5V) corresponding to the SOC (state of available charge of the remaining charge) of the first material at 0-100% in different environments, and obtain the relationship between the compensation capacity and the compensation voltage of the first material at different temperatures.

[0109] Specifically, at different temperatures, sampling can be performed at intervals of 1% of the capacity of the first material, that is, starting from 0% capacity, sampling is performed every 1% of the capacity;

[0110] Furthermore, a lithium-ion battery containing the first material can be charged at a constant current with a smaller rate (such as 0.01C), with 1% of the capacity as the charging target. At each sampling point, 1% of the capacity is compensated for the battery, and the voltage value at this time is recorded;

[0111] According to the above steps, the voltages V0 - V100 corresponding to the first material at 0 - 100% capacity compensation are collected in sequence to obtain multiple sets of data on compensation capacity and compensation voltage. Then, linear fitting can be performed on the multiple sets of data to obtain the linear relationship between compensation capacity and compensation voltage of the first material at different temperatures.

[0112] Further, in some embodiments of the above step S101, the lithium - ion battery can be initially charged based on the first voltage at the first temperature.

[0113] For example, if the first compensation capacity is 5% of the battery capacity, the lithium - ion battery can be initially charged through the compensation voltage corresponding to 5% of the compensation capacity at the first temperature.

[0114] During the initial charge, capacity compensation is performed based on the first temperature and the first voltage, enabling lithium ions to diffuse into the negative electrode material faster and participate in the chemical reaction in the negative electrode material, thus making it easier to form a dense and stable SEI.

[0115] The above is a further description of step S101. Next, a further description of step S102 will be continued.

[0116] In some embodiments of the above step S102, the capacity attenuation rate of the lithium - ion battery can be obtained when the lithium - ion battery undergoes normal charge - discharge cycles.

[0117] Among them, normal charge - discharge cycles are for charge - discharge use or storage in a normal environment. The normal environmental conditions can be: temperature - 30 - 60°C, humidity 20% - 95%RH, charging with a constant current I (0 - 5C), charging cut - off voltage U1 (3.3 - 3.7V), discharging with a constant current I' (0 - 5C), and lower cut - off voltage U1 (2.0 - 2.9V).

[0118] Further, in some embodiments, the capacity attenuation rate of the lithium - ion battery can be obtained by subjecting the lithium - ion battery to normal charge - discharge cycles.

[0119] The above is a further description of step S102. Next, a further description of step S103 will be continued.

[0120] In some embodiments of the above step S103, as the number of charge - discharge cycles increases, the number of lithium ions in the electrode material will decrease, thereby reducing the battery capacity. Therefore, a threshold corresponding to the capacity attenuation rate can be preset. When the capacity attenuation rate exceeds the preset threshold, capacity compensation is performed based on the second condition. Among them, the second condition is the preset compensation condition for capacity compensation when the capacity attenuation rate reaches the preset threshold during the normal charge - discharge cycle of the lithium - ion battery, and the capacity attenuation rate can be obtained through the battery management system BMS.

[0121] Specifically, the second condition may include a preset second voltage, a second compensation capacity, a second temperature, a second charging current, a second discharging current, etc.

[0122] Among them, the second voltage may be 3.7 - 4.5V, and the second voltage is greater than the first voltage; the second compensation capacity may account for 5% - 20% of the maximum compensation capacity; the second temperature may be in the normal temperature range, specifically 20 - 30°C; the second charging current may be 0 - 10C, and the second discharging current may be 0 - 20C.

[0123] Furthermore, in some embodiments of the above step S103, the second compensation capacity may be obtained and compensated when the capacity attenuation rate of the lithium-ion battery exceeds a preset threshold.

[0124] In some embodiments, according to the characteristics of different lithium-ion batteries, such as the composition of the battery material, the preparation process, the use conditions, etc., the capacity loss during the first charge may be judged, and the second compensation capacity may be preset.

[0125] For example, the second compensation capacity is set to 1% - 3% of the battery capacity, or 5% - 20% of the maximum capacity compensation amount of the first material, etc., which is not limited here.

[0126] Furthermore, after obtaining the second compensation capacity, the second voltage corresponding to the second compensation capacity may be obtained based on the relationship between the compensation capacity and the compensation voltage of the first material.

[0127] Specifically, based on the relationship between the compensation capacity and the compensation voltage of the first material at the preset compensation temperature, the second voltage corresponding to the second compensation capacity at the second temperature may be obtained.

[0128] During the use of the lithium-ion battery, the diffusion rate of lithium ions in the electrode material will gradually slow down, resulting in the concentration and distribution of lithium ions in the electrode material tending to be stable. Therefore, capacity compensation can be carried out in the normal temperature range to reduce the battery maintenance cost.

[0129] For the convenience and brevity of description, the relevant description of obtaining the second voltage corresponding to the second compensation capacity at the second temperature may refer to the content described in the embodiment of the above step S101, which will not be repeated here.

[0130] Furthermore, the capacity of the lithium-ion battery may be compensated based on the second voltage at the second temperature.

[0131] In some embodiments of the above step S103, the second condition further includes a preset third voltage and a fourth voltage, where the third voltage is less than the fourth voltage, and the third voltage is greater than the first voltage.

[0132] As the number of capacity compensation times increases, a higher voltage is required to activate the first material. Therefore, the voltage for subsequent capacity compensation should be higher than that for prior capacity compensation.

[0133] In some embodiments, referring to the attached Figure 2 , Figure 2 FIG. is a schematic flow chart of the main steps for capacity compensation of a lithium-ion battery based on a second condition according to an embodiment of the present application. As Figure 2 shown, it mainly includes the following steps S201 to step S202:

[0134] Step S201: When the capacity attenuation rate exceeds a preset threshold, perform a second capacity compensation on the lithium-ion battery based on a third voltage;

[0135] Step S202: After the second capacity compensation, when the capacity attenuation rate exceeds the preset threshold, perform a third capacity compensation on the lithium-ion battery based on a fourth voltage.

[0136] Further, in some embodiments, the preset threshold may include a first threshold and a second threshold, and the first threshold is less than or equal to the second threshold.

[0137] Specifically, as the usage time and number of cycles of the battery increase, the capacity attenuation of the battery will become more and more serious. Therefore, multiple preset thresholds can be set. The multiple preset thresholds can be between 0% - 40%. For example, the first threshold is set to 10% and the second threshold is set to 20%, etc., and the capacity compensation of the lithium-ion battery is performed step by step.

[0138] In some embodiments, referring to the attached Figure 3 , Figure 3 FIG. is a schematic flow chart of the main steps for capacity compensation of a lithium-ion battery based on a second condition according to another embodiment of the present application. As Figure 3 shown, it mainly includes the following steps S301 to step S302:

[0139] Step S301: When the capacity attenuation rate exceeds the first threshold, perform a second capacity compensation on the lithium-ion battery based on a third voltage;

[0140] Step S302: After the second capacity compensation, when the capacity attenuation rate exceeds the second threshold, perform a third capacity compensation on the lithium-ion battery based on a fourth voltage.

[0141] The above is a further description of step S103. Next, step S104 will be further described.

[0142] In some embodiments of the above step S104, during the normal charge and discharge cycles of the lithium-ion battery, capacity compensation can be performed when the capacity attenuation rate exceeds a preset threshold until the cumulative compensated capacity reaches the maximum compensated capacity of the first material, at which point capacity compensation for the battery is no longer performed, and the normal charge and discharge cycles continue until the end of the life cycle.

[0143] Among them, the preset compensated capacity for each capacity compensation can be the same or different, and the cumulative compensated capacity is less than or equal to the maximum compensated capacity of the first material. In practical applications, those skilled in the art can set it according to specific scenarios, and no limitation is made here.

[0144] The above is a further description of step S104.

[0145] Next, the capacity compensation method for the lithium-ion battery provided by the present application will be described through embodiments. The first material in the embodiments and comparative examples of the present application is Li5FeO4, but it can be expected that using other first materials listed above can also achieve comparable effects.

[0146] Specifically, it includes the following Comparative Examples 1-2 and Embodiments 1-5:

[0147] Comparative Example 1

[0148] The lithium-ion battery without adding the first material performs the following steps:

[0149] (1) Charge at a constant current of 0.5C at 25°C, and the charge cut-off voltage is 3.65V;

[0150] (2) Discharge at a constant current of 1C at 25°C, and the discharge cut-off voltage is 2.3V;

[0151] (3) Repeat steps (1)-(2) until the end of the battery life cycle.

[0152] Comparative Example 2

[0153] The lithium-ion battery adding 1% (mass percentage of the first material in the positive electrode material, the same below) of Li5FeO4 performs the following steps:

[0154] (1) Charge at a constant current of 0.05C at 25°C, and the charge cut-off voltage is 4.2V;

[0155] (2) Discharge at a constant current of 1C at 25°C, and the discharge cut-off voltage is 2.3V;

[0156] (3) Charge at a constant current of 0.5C at 25°C, and the charge cut-off voltage is 3.65V;

[0157] (4) Repeat steps (2)-(3) until the end of the battery life cycle.

[0158] In the following Examples 1 - 5, the first threshold is 5%, the second threshold is 7%, and the third threshold is 10%.

[0159] Example 1:

[0160] The lithium - ion battery with 1% of Li5FeO4 added performs the following steps:

[0161] (1) Charge at a constant current of 0.05C at 25°C, and the charge cut - off voltage is 3.9V;

[0162] (2) - (3) are the same as Comparative Example 2;

[0163] (4) Repeat steps (2) - (3) until the obtained capacity attenuation rate is greater than 5%;

[0164] (5) Charge at a constant current of 0.05C at 25°C, and the charge cut - off voltage is 4.08V; discharge at a constant current of 1C, and the discharge cut - off voltage is 2.3V;

[0165] (6) Repeat steps (2) - (3) until the obtained capacity attenuation rate is greater than 7%, charge at a constant current of 0.05C at 25°C, and the charge cut - off voltage is 4.2V; discharge at a constant current of 1C, and the discharge cut - off voltage is 2.3V;

[0166] (7) When the cumulative compensation capacity reaches the maximum compensation capacity, repeat steps (2) - (3) until the end of the battery life cycle.

[0167] Example 2

[0168] The lithium - ion battery with 2% of Li5FeO4 added performs the following steps:

[0169] (1) - (7) are the same as Example 1.

[0170] Example 3

[0171] The lithium - ion battery with 2% of Li5FeO4 added performs the following steps:

[0172] (1) Charge at a constant current of 0.05C at 25°C, and the charge cut - off voltage is 3.8V;

[0173] (2) - (3) are the same as Example 1;

[0174] (4) Repeat steps (2) - (3) until the obtained capacity attenuation rate is greater than 5%;

[0175] (5) Charge at a constant current of 0.05C at 25°C, and the charge cut - off voltage is 3.9V; discharge at a constant current of 1C, and the discharge cut - off voltage is 2.3V;

[0176] (6) Repeat steps (2)-(3) until the obtained capacity attenuation rate is greater than 7%. Charge at a constant current of 0.05C at 25°C, with a charging cut-off voltage of 4.0V; discharge at a constant current of 1C, with a discharge cut-off voltage of 2.3V;

[0177] (7) Repeat steps (2)-(3) until the obtained capacity attenuation rate is greater than 10%. Charge at a constant current of 0.05C at 25°C, with a charging cut-off voltage of 4.1V; discharge at a constant current of 1C, with a discharge cut-off voltage of 2.3V;

[0178] (8) When the cumulative compensated capacity reaches the maximum compensated capacity, repeat steps (2)-(3) until the end of the battery life cycle.

[0179] Example 4

[0180] The lithium-ion battery added with 1% of Li5FeO4 performs the following steps:

[0181] (1) Charge at a constant current of 0.05C at 45°C, with a charging cut-off voltage of 3.9V;

[0182] (2) Discharge at a constant current of 1C at 45°C, with a discharge cut-off voltage of 2.3V;

[0183] (3) Charge at a constant current of 0.5C at 45°C, with a charging cut-off voltage of 3.65V;

[0184] (4) Repeat steps (2)-(3) until the capacity attenuation rate is greater than 5%;

[0185] (5) Charge at a constant current of 0.05C at 45°C, with a charging cut-off voltage of 4.08V; discharge at a constant current of 1C, with a discharge cut-off voltage of 2.3V;

[0186] (6) Repeat steps (2)-(3) until the capacity attenuation rate is greater than 7%. Charge at a constant current of 0.05C at 45°C, with a charging cut-off voltage of 4.2V; discharge at a constant current of 1C, with a discharge cut-off voltage of 2.3V;

[0187] (7) When the cumulative compensated capacity reaches the maximum compensated capacity, repeat steps (2)-(3) until the end of the battery life cycle.

[0188] Example 5

[0189] The lithium-ion battery added with 2% of Li5FeO4 performs the following steps:

[0190] (1) Charge at a constant current of 0.05C at 45°C, with a charging cut-off voltage of 3.8V;

[0191] (2)-(4) are the same as in Example 4;

[0192] (5) Charge at a constant current of 0.05C at 45°C, with a charging cut-off voltage of 3.9V; discharge at a constant current of 1C, with a discharge cut-off voltage of 2.3V;

[0193] (6) Repeat steps (2)-(3) until the capacity attenuation rate is greater than 7%, then charge at a constant current of 0.05C at 45°C, with a charging cut-off voltage of 4.0V; discharge at a constant current of 1C, with a discharge cut-off voltage of 2.3V;

[0194] (7) Repeat steps (2)-(3) until the capacity attenuation rate is greater than 10%, then charge at a constant current of 0.05C at 45°C, with a charging cut-off voltage of 4.1V; discharge at a constant current of 1C, with a discharge cut-off voltage of 2.3V;

[0195] (8) When the cumulative compensation capacity reaches the maximum compensation capacity, repeat steps (2)-(3) until the end of the battery life cycle.

[0196] The specific test data and test results of the above Comparative Examples 1-2 and Examples 1-5 are shown in Table 1 below.

[0197] Table 1

[0198] Among them, from Comparative Example 1 and Comparative Example 2, it can be seen that only by performing capacity compensation during the first charge, the cycle life of the lithium-ion battery is also improved;

[0199] From Comparative Example 2 and Example 1, it can be seen that when the addition amount of the first material is the same, performing capacity compensation in batches results in a longer cycle life of the lithium-ion battery compared to performing capacity compensation only during the first charge;

[0200] From Example 2 and Example 3, it can be seen that when the addition amount of the first material is the same, compensating the first material in multiple times and gradually reducing the compensation capacity each time results in a longer cycle life of the lithium-ion battery compared to continuously compensating the same capacity multiple times;

[0201] From Example 3 and Example 5, it can be seen that when the addition amount of the first material is the same, within the preset compensation temperature range (such as 20-70°C), the higher the compensation temperature, the longer the cycle life of the lithium-ion battery.

[0202] In addition, in some embodiments, only one preset threshold may be set, and capacity compensation is performed when the capacity attenuation rate exceeds the preset threshold.

[0203] It should be noted that if the preset threshold is small (e.g., 5%), multiple capacity compensations may be performed in the early stage of battery use, and the first material will be used up further in the early stage of battery use, resulting in the inability to continuously perform capacity compensation during the middle and late stages of battery use, which is not conducive to the long-term use of the battery; if the preset threshold is large (e.g., 10%), the compensation may be performed only when the user feels obvious capacity attenuation of the battery, bringing a bad user experience.

[0204] Therefore, in practical applications, the number and specific values of the preset threshold can be set according to specific requirements, so that the lithium-ion battery can continuously compensate for the lost active lithium ions to a certain extent during the cycling process, ensuring the long cycling life of the battery.

[0205] According to the above test results, it can be seen that using the capacity compensation method of the lithium-ion battery provided by the present application can extend the service life of the battery, reduce the frequency of battery replacement by users, meet the user's requirements for battery life while reducing the user's usage cost, and improve the user's usage experience.

[0206] Through the capacity compensation method of the lithium-ion battery provided by the present application, capacity compensation is performed during the first charge, which can improve the first charge-discharge efficiency of the battery and avoid the risk of lithium deposition on the negative electrode during the first charge. During subsequent charge-discharge processes, compensation is triggered according to the capacity attenuation situation, which can continuously compensate for the lost active lithium ions to a certain extent during the cycling process, avoiding the problem of low energy density caused by the inability to utilize the excessive negative electrode active material used for the first lithium compensation during subsequent cycling processes, and ensuring a long cycling life while ensuring a high energy density.

[0207] It should be pointed out that although the above embodiments describe the various steps in a specific order, those skilled in the art can understand that in order to achieve the effects of the present application, it is not necessary to execute the different steps in such an order. They can be executed simultaneously (in parallel) or in other orders, and these changes are all within the protection scope of the present application.

[0208] Those skilled in the art can understand that all or part of the processes in the methods of the above-mentioned embodiments of the present application can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned method embodiments can be realized. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable storage medium can include: any entity or device, medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal, and software distribution medium, etc., that can carry the computer program code.

[0209] Furthermore, the present application also provides an electronic device. Refer to the attached Figure 4 , Figure 4 is a schematic diagram of the main structure of an electronic device according to an embodiment of the present application. As Figure 4 shown, the electronic device in the embodiment of the present application mainly includes a processor 401 and a storage device 402. The storage device 402 can be configured to store a program for executing the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiments. The processor 401 can be configured to execute the program in the storage device 402, and this program includes but is not limited to the program for executing the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiments. For the sake of convenience of description, only the parts related to the embodiments of the present application are shown. For the specific technical details not disclosed, please refer to the method part of the embodiments of the present application.

[0210] In some possible implementation manners of the present application, the electronic device may include multiple processors 401 and multiple storage devices 402. The program for executing the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiments can be divided into multiple sub-programs, and each sub-program can be loaded and run by the processor 401 respectively to execute different steps of the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiments. Specifically, each sub-program can be stored in a different storage device 402 respectively, and each processor 401 can be configured to execute the program in one or more storage devices 402 to jointly realize the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiments, that is, each processor 401 respectively executes different steps of the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiments to jointly realize the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiments.

[0211] The above-mentioned multiple processors 401 may be processors deployed on the same device. For example, the above-mentioned electronic device may be a high-performance device composed of multiple processors, and the above-mentioned multiple processors 401 may be the processors configured on the high-performance device. In addition, the above-mentioned multiple processors 401 may also be processors deployed on different devices. For example, the above-mentioned electronic device may be a server cluster, and the above-mentioned multiple processors 401 may be the processors on different servers in the server cluster.

[0212] Furthermore, the present application also provides a driving device. In an embodiment of a driving device according to the present application, the driving device may include a driving device body and the electronic device described in the above-mentioned electronic device embodiment.

[0213] Furthermore, the present application also provides a computer-readable storage medium. In an embodiment of a computer-readable storage medium according to the present application, the computer-readable storage medium may be configured to store a program for executing the capacity compensation method of the lithium-ion battery in the above-mentioned method embodiment. This program may be loaded and run by a processor to implement the above-mentioned capacity compensation method of the lithium-ion battery. For ease of description, only the parts related to the embodiments of the present application are shown. For the specific technical details not disclosed, please refer to the method part of the embodiments of the present application. The computer-readable storage medium may be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiments of the present application is a non-transitory computer-readable storage medium.

[0214] It should be noted that the relevant user personal information that may be involved in the embodiments of the present application is all processed in strict accordance with the requirements of laws and regulations, following the principles of legality, legitimacy, and necessity, for reasonable purposes based on business scenarios, and is the personal information actively provided by the user during the use of the product / service or generated due to the use of the product / service, as well as the personal information obtained with the user's authorization.

[0215] The user personal information processed by the present application may vary depending on the specific product / service scenario. It is subject to the specific scenario of the user's use of the product / service and may involve the user's account information, device information, driving information, vehicle information, or other relevant information. The present application will treat the user's personal information and its processing with a high degree of diligence.

[0216] The present application attaches great importance to the security of user personal information and has taken security protection measures that meet industry standards and are reasonable and feasible to protect the user's information and prevent personal information from being accessed, publicly disclosed, used, modified, damaged, or lost without authorization.

[0217] So far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings. However, it is easily understood by those skilled in the art that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present application.

Claims

1. A method for compensating the capacity of a lithium-ion battery, characterized in that, The lithium-ion battery includes a first material, and the first material is a capacity compensation material. The method includes: S1. Perform the first charge on the lithium-ion battery based on a first condition; S2. Obtain the capacity attenuation rate of the lithium-ion battery by performing a conventional charge-discharge cycle on the lithium-ion battery; S3. When the capacity attenuation rate exceeds a preset threshold, perform capacity compensation on the lithium-ion battery based on a second condition; S4. Repeat S2 - S3 until the cumulative compensation capacity reaches the maximum compensation capacity of the first material; wherein, the first condition includes a first voltage, the second condition includes a second voltage, and the first voltage is less than the second voltage.

2. The method for compensating the capacity of a lithium-ion battery according to claim 1, characterized in that, The first condition further includes a first compensation capacity, and the second condition further includes a second compensation capacity; the method further includes: Based on the relationship between the compensation capacity and the compensation voltage of the first material, obtain the first voltage corresponding to the first compensation capacity and the second voltage corresponding to the second compensation capacity.

3. The method for compensating the capacity of a lithium-ion battery according to claim 2, characterized in that, The first condition further includes a first temperature, and the second condition further includes a second temperature; the method further includes: Based on the relationship between the compensation capacity and the compensation voltage of the first material at a preset compensation temperature, obtain the first voltage corresponding to the first compensation capacity at the first temperature and the second voltage corresponding to the second compensation capacity at the second temperature.

4. The method for compensating the capacity of a lithium-ion battery according to claim 3, characterized in that, The performing the first charge on the lithium-ion battery based on the first condition includes: At the first temperature, perform the first charge on the lithium-ion battery based on the first voltage; and / or, the performing the capacity compensation on the lithium-ion battery based on the second condition includes: At the second temperature, perform the capacity compensation on the lithium-ion battery based on the second voltage.

5. The method for compensating the capacity of a lithium-ion battery according to claim 2, characterized in that, The first material is added to the positive electrode material of the lithium-ion battery. The method further includes: Based on the mass of the first material, the specific capacity of the positive electrode material of the lithium-ion battery, the irreversible specific capacity of the first material, and the compensation efficiency of the first material, obtain the maximum compensation capacity of the first material; wherein, the compensation efficiency of the first material is the ratio of the theoretical compensation capacity to the actual compensation capacity of the first material.

6. The method for compensating the capacity of a lithium-ion battery according to claim 5, characterized in that, The method further includes: Obtain the first compensation capacity and the second compensation capacity; wherein, the first compensation capacity accounts for 20% - 50% of the maximum compensation capacity.

7. The method for compensating the capacity of a lithium-ion battery according to claim 1, characterized in that, The second condition further includes a third voltage and a fourth voltage, and the third voltage is less than the fourth voltage; The performing the capacity compensation on the lithium-ion battery based on the second condition when the capacity attenuation rate exceeds the preset threshold includes: When the capacity attenuation rate exceeds the preset threshold, perform a second capacity compensation on the lithium-ion battery based on the third voltage; After the second capacity compensation, when the capacity attenuation rate exceeds the preset threshold, perform a third capacity compensation on the lithium-ion battery based on the fourth voltage.

8. The method for compensating the capacity of a lithium-ion battery according to claim 7, characterized in that, The preset threshold includes a first threshold and a second threshold, and the first threshold is less than the second threshold; when the capacity attenuation rate exceeds the preset threshold, performing capacity compensation on the lithium-ion battery based on the second condition further includes: When the capacity attenuation rate exceeds the first threshold, performing the second capacity compensation on the lithium-ion battery based on the third voltage; After the second capacity compensation, when the capacity attenuation rate exceeds the second threshold, performing the third capacity compensation on the lithium-ion battery based on the fourth voltage.

9. An electronic device, comprising a processor and a storage device, the storage device being adapted to store a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by the processor to execute the capacity compensation method of the lithium-ion battery according to any one of claims 1 to 8.

10. A driving device, characterized in that, The driving device includes a driving device body and the electronic device according to claim 9.

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