Formation method of pre-lithiated battery and battery

Abstract

The application belongs to the technical field of battery manufacturing, and discloses a formation method of a pre-lithiated battery and the battery. The formation method comprises the following steps: performing first charging on a lithium supplement battery after liquid injection to a preset SOC to form an SEI film; performing second charging to make the voltage rise to V1, so that the positive active material continues to be delithiated, and then standing; performing third charging to make the voltage rise to V2, and V2 is the cut-off voltage of the decomposition of the lithium supplement agent; wherein the temperature of the first charging is T1, the temperature of the standing is T2, and the temperature of the third charging is T3, T1 < T2, and T2 < T3. The formation method can obtain sufficient lithium supplement effect, the charging specific capacity of the lithium supplement agent is high, and the problem of lithium precipitation on the negative electrode surface can be effectively solved. After the battery is fully charged and disassembled, the negative electrode interface of the battery cell is good, there is no lithium precipitation spot, and the cycle performance of the battery is improved.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology, and relates to a lithium battery formation method, specifically to a pre-lithiation battery formation method and battery. Background Technology

[0002] In recent years, cathode pre-lithiation technology has been developed and applied to improve the cycle life of energy storage cells (such as lithium iron phosphate cells). Cathode pre-lithiation technology involves adding lithium-rich materials with high irreversible capacity, such as lithium iron phosphate (Li5FeO4, LFO) and lithium nickel phosphate (Li2NiO2, LNO), to the cathode electrode. During the initial formation of the cell, the pre-lithiation agent decomposes, releasing lithium ions that embed into the anode. During discharge, some lithium ions are stored in the anode to compensate for lithium consumption in later stages of the cycle.

[0003] The purpose of lithium-ion battery formation is to form a stable solid electrolyte interphase (SEI) film on the surface of the negative electrode (e.g., a graphite negative electrode) during the first charge. The voltage range for SEI film formation varies depending on the positive and negative electrode formulations and electrolyte composition, but SEI growth is typically complete once the charge reaches below 20% SOC. Therefore, lithium iron phosphate cells are usually charged to 10%–50% SOC during formation, after which the cell enters the high-temperature aging stage.

[0004] However, in pre-lithiated cells, a voltage of approximately 4.2V is required for complete decomposition of the positive electrode lithium replenisher, which is higher than the voltage required for a full charge and 100% SOC of a lithium iron phosphate cell. Therefore, to activate the lithium replenisher, it is unavoidable to fully charge the lithium iron phosphate cell. However, because the negative electrode has not undergone the expansion required for charging during the first charge, and the electrolyte has not been fully wetted, full charging can easily lead to lithium deposition on the surface of the negative electrode.

[0005] Therefore, providing a formation method to avoid lithium plating, improve cell interface conditions, and enhance the capacity utilization of lithium replenishment agents is an urgent technical problem to be solved. Summary of the Invention

[0006] In view of the above-mentioned technical problems existing in the prior art, the purpose of this invention is to provide a formation method and battery for a pre-lithiation battery.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for forming a pre-lithiated battery, the method comprising the following steps:

[0009] The lithium battery after liquid injection is first charged to a preset SOC to form an SEI film;

[0010] Perform the second charging to raise the voltage to V1, causing further delithiation of the positive electrode active material, and then let it stand;

[0011] Perform the third charging to raise the voltage to V2, where V2 is the cut-off voltage for the decomposition of the lithium supplement agent.

[0012] Among them, the temperature of the first charging is T1, the temperature of the standing is T2, and the temperature of the third charging is T3, where T1 < T2 and T2 < T3.

[0013] In the method of the present invention, when the third charging reaches the cut-off voltage for the decomposition of the lithium supplement agent, the lithium supplement agent is completely decomposed.

[0014] In some embodiments, the starting voltage for the decomposition of the lithium supplement agent is less than V1. In the second charging interval, a small amount of decomposition of the lithium supplement agent occurs and the decomposition rate is slow. In the third charging interval, a large amount of decomposition of the lithium supplement agent occurs and the decomposition rate significantly increases. When the voltage rises to the cut-off voltage for the decomposition of the lithium supplement agent, the lithium supplement agent is completely decomposed.

[0015] In the formation method of the present invention, the first charging stage is carried out at a lower temperature, which is beneficial to the formation of a dense SEI film; after the second charging until delithiation of the positive electrode active material occurs, standing at a higher temperature can make the infiltration of the electrolyte more sufficient, improve the cell interface situation, and avoid the problem of lithium deposition caused by high SOC during the third charging; the third charging is carried out at a higher temperature, which can make the lithium supplement agent decompose sufficiently at a higher rate compared to the prior art (such as 0.02C - 0.05C), facilitating the shortening of the formation time and improving the capacity utilization of the lithium supplement agent. The combined effect of the above factors can not only form a dense SEI film, but also make the electrolyte fully infiltrate the lithium supplement battery and promote the effective decomposition of the lithium supplement agent. Therefore, the method of the present invention can obtain a sufficient lithium supplement effect, the charged gram capacity of the lithium supplement agent is high, and it can also effectively solve the problem of lithium deposition on the negative electrode surface. After the battery is fully charged and disassembled, the negative electrode interface of the cell is good, without lithium deposition spots, and the cycle performance of the battery is improved.

[0016] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved.

[0017] Preferably, 20°C < T1 < 30°C, for example, it can be 22°C, 24°C, 25°C, 26°C or 28°C, etc. Within this lower temperature range, it is not only beneficial to obtain a dense SEI film, but usually can be carried out at room temperature without additional control of the charging environment.

[0018] Preferably, 40°C < T2 < 50°C, for example, it can be 42°C, 43°C, 45°C, 47°C, 48°C, etc. Standing at this relatively high temperature is beneficial for the sufficient infiltration of the electrolyte, thereby avoiding the problem of lithium plating on the negative electrode during the battery charging process.

[0019] Preferably, 50°C ≤ T3 ≤ 65°C, for example, it can be 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 61°C, 63°C, 65°C, etc., and preferably 50°C < T3 < 65°C. If the temperature T3 of the third charging is too low, the promotion effect on the decomposition of the lithium supplement agent is poor, resulting in a decrease in the charging specific capacity of the lithium supplement agent and a decrease in the pre-stored lithium amount in the negative electrode, leading to a decrease in the cycle performance; if the temperature T3 of the third charging is too high, it will affect the cell interface, resulting in a decrease in the cycle performance.

[0020] Preferably, after the voltage rises to V1, the standing time is 6h - 12h, for example, it can be 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc.

[0021] Preferably, the charging rate of the first charging is 0.02C - 0.3C. Conducting the first charging under a low charging rate is beneficial for forming a dense SEI film.

[0022] Preferably, the preset SOC is 10% - 50% SOC and does not include 50% SOC, for example, it can be 10% SOC, 12% SOC, 14% SOC, 15% SOC, 16% SOC, 17% SOC, 18% SOC, 20% SOC, 25% SOC, 30% SOC, 35% SOC, 40% SOC, 42% SOC, 45% SOC, 48% SOC, 49% SOC, etc. Within this preset SOC range, the SEI film is basically grown.

[0023] Preferably, after the lithium supplement battery is charged to the preset SOC, charging is stopped, and it is left standing at 40°C - 50°C (for example, it can be 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, etc.) for 12h - 48h (for example, it can be 12h, 1s4h, 16h, 18h, 20h, 22h, 25h, 27h, 30h, 32h, 34h, 35h, 37h, 40h, 43h, 44h, 46h, 48h, etc.). By setting this step, the electrolyte can be fully infiltrated, and the second charging can be carried out at a relatively high charging rate, which can not only avoid the problem of lithium plating on the negative electrode but also shorten the formation time.

[0024] Preferably, the charging rate of the second charging is 0.3C - 0.6C, for example, it can be 0.3C, 0.4C, 0.5C, 0.6C, etc.

[0025] Preferably, when the voltage rises to V1, the supplementary lithium battery is charged to more than 80% SOC and less than or equal to 100% SOC. For example, it can be 80% SOC, 82% SOC, 85% SOC, 88% SOC, 90% SOC, 93% SOC, 96% SOC, 98% SOC or 100% SOC, etc. At this time, most of the cathode active materials are de-lithiated, and the supplementary lithium agent is partially de-lithiated.

[0026] Preferably, the temperature of the second charging is 40°C to 50°C. For example, it can be 40°C, 42°C, 43°C, 45°C, 47°C, 48°C or 50°C, etc.

[0027] Preferably, 3.4V < V1 < 3.65V. Exemplarily, V1 can be 3.4V, 3.42V, 3.45V, 3.47V, 3.5V, 3.53V, 3.56V, 3.58V or 3.6V, etc.

[0028] Preferably, the charging rate of the third charging is 0.1C to 0.3C. For example, it can be 0.1C, 0.12C, 0.14C, 0.16C, 0.18C, 0.2C, 0.22C, 0.25C, 0.27C or 0.3C, etc.

[0029] Preferably, V2 is 4.05V to 4.3V. For example, it can be 4.05V, 4.08V, 4.1V, 4.12V, 4.14V, 4.15V, 4.18V, 4.2V, 4.23V, 4.26V, 4.28V or 4.3V, etc.

[0030] Preferably, after the voltage rises to V2, the charging is stopped, and the supplementary lithium battery is left standing at 40°C to 50°C (for example, it can be 40°C, 42°C, 44°C, 46°C, 48°C or 50°C, etc.) for 12h to 48h (for example, it can be 12h, 14h, 16h, 18h, 20h, 22h, 25h, 27h, 30h, 32h, 34h, 35h, 37h, 40h, 43h, 44h, 46h or 48h, etc.). This process can make the electrolyte fully infiltrate, the SEI film on the negative electrode surface more stable, and at the same time make the side reaction between the supplementary lithium agent and the electrolyte more sufficient, which is beneficial to discharging the side reaction gas.

[0031] Preferably, the supplementary lithium battery after liquid injection includes a positive electrode plate, a negative electrode plate, a separator and an electrolyte. The positive electrode plate includes a positive electrode current collector and a positive electrode material layer provided on the surface of the positive electrode current collector. The positive electrode material layer includes a positive electrode active material and a supplementary lithium agent.

[0032] Preferably, the lithium replenishing agent accounts for 0.5% to 5% of the mass of the positive electrode material layer, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc.

[0033] Secondly, the present invention provides a battery, which is prepared by the following method: after liquid injection, the lithium-ion battery is formed by the method described in the first aspect, then injected with liquid again, sealed, and capacity-divided.

[0034] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0035] Compared with existing technologies, the present invention has the following beneficial effects:

[0036] (1) In the formation method of the present invention, the first charging stage is carried out at a lower temperature, which is conducive to the formation of a dense SEI film; after the second charging to the point where the positive electrode active material undergoes delithiation, it is left to stand at a higher temperature, which can make the electrolyte more fully wetted, improve the cell interface, and avoid the problem of lithium plating caused by high SOC during the third charging; the third charging is carried out at a higher temperature, which can make the lithium replenishing agent fully decomposed at a higher rate than the prior art (e.g., 0.02C~0.05C), which is conducive to shortening the formation time. The combined effect of the above factors can form a dense SEI film, make the electrolyte fully wet the lithium replenishing battery, and promote the effective decomposition of the lithium replenishing agent. Therefore, the method of the present invention can obtain a sufficient lithium replenishment effect, the charging specific capacity of the lithium replenishing agent is high, and it can also effectively solve the problem of lithium plating on the negative electrode surface. After the battery is fully charged and disassembled, the negative electrode interface of the cell is good and there are no lithium plating spots, and the cycle performance of the battery is improved.

[0037] (2) The formation method of the present invention can improve the charging capacity of the lithium replenishing agent, the charging capacity of the lithium replenishing agent LFO is above 650mAh / g, and the energy retention rate of the battery obtained after formation is above 100% after 1000 cycles. Detailed Implementation

[0038] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0039] Preparation Example 1

[0040] A lithium-ion battery that has undergone electrolyte injection and subsequent replenishment is provided, the preparation method of which includes:

[0041] Preparation of positive electrode sheet: Lithium iron phosphate is used as the positive electrode active material, and lithium iron phosphate (Li5FeO4, LFO) is used as the positive electrode lithium supplement. The positive electrode active material, positive electrode lithium supplement, conductive agent Super P and binder PVDF are mixed evenly in NMP. The ratio of positive electrode active material: lithium supplement: conductive agent: binder (mass ratio) is 93:2:2:3 to obtain a positive electrode slurry. The positive electrode slurry is coated on aluminum foil, dried and rolled to form a positive electrode material layer on the surface of the aluminum foil, thus obtaining the positive electrode sheet.

[0042] Preparation of negative electrode sheet: Using graphite as the negative electrode active material, the negative electrode active material, conductive agent Super P, SBR and CMC are mixed evenly in water. The mass ratio of negative electrode active material: conductive agent: SBR: CMC is 96:1:1.5:1.5 to obtain a negative electrode slurry. The negative electrode slurry is coated on copper foil, dried and rolled to form a negative electrode material layer on the surface of the copper foil, thus obtaining the negative electrode sheet.

[0043] The electrolyte is lithium hexafluorophosphate.

[0044] The positive electrode, negative electrode, and separator are stacked sequentially, with the separator separating the positive and negative electrodes, to obtain a battery cell. After injecting electrolyte, the cell is immersed at 45°C for 36 hours to obtain a lithium-ion battery after electrolyte injection. The lithium-ion battery after electrolyte injection is a 320Ah square aluminum-cased battery cell.

[0045] Example 1

[0046] This embodiment provides a method for forming a pre-lithiated battery, the method comprising the following steps:

[0047] At an ambient temperature of 25°C, the lithium-ion battery after liquid injection (Preparation Example 1) was charged for the first time. The first charge was performed by charging at 0.02C to 10% SOC and then continuing to charge at 0.1C to 20% SOC.

[0048] Stop charging and place the battery cell at 45℃ for 12 hours.

[0049] At an ambient temperature of 45°C, a second charge is performed, which is: charging at 0.3C to 3.5V. At this time, the battery is charged to 85% SOC. At this voltage, most of the positive electrode active material undergoes delithiation, and the lithium replenishing agent undergoes partial delithiation.

[0050] Stop charging and place the battery cell at 45℃ for 12 hours.

[0051] At an ambient temperature of 55°C, a third charge is performed, which is a charge at 0.2C to 4.2V, at which the positive electrode lithium replenishment agent decomposes.

[0052] Stop charging and place the battery cell at 45℃ for 24 hours to complete the formation process.

[0053] The cells after the above formation are then injected with electrolyte a second time, sealed, and then subjected to 0.5P discharge capacity testing.

[0054] Example 2

[0055] The difference from Example 1 is that the temperature of the third charge is adjusted to 50°C.

[0056] Example 3

[0057] The difference from Example 1 is that the temperature of the third charge is adjusted to 65°C.

[0058] Example 4

[0059] This embodiment provides a method for forming a pre-lithiated battery, the method comprising the following steps:

[0060] At an ambient temperature of 20°C, the lithium-ion battery after liquid injection (Preparation Example 1) was charged for the first time. The first charge was performed by charging at 0.02C to 10% SOC and then continuing to charge at 0.05C to 20% SOC.

[0061] Stop charging and place the battery cell at 40℃ for 48 hours.

[0062] At an ambient temperature of 47°C, a second charge is performed, which is: charging at 0.4C to 3.55V. At this time, the battery is charged to 90% SOC. At this voltage, most of the positive electrode active material undergoes delithiation, and the lithium replenishing agent undergoes partial delithiation.

[0063] Stop charging and place the battery cell at 46℃ for 18 hours.

[0064] At an ambient temperature of 52°C, a third charge is performed, which is a charge at 0.1C to 4.1V, at which the positive electrode lithium replenishment agent decomposes.

[0065] Stop charging and place the battery cell at 40℃ for 12 hours to complete the formation process.

[0066] The cells after the above formation are then injected with electrolyte a second time, sealed, and then subjected to 0.5P discharge capacity testing.

[0067] Example 5

[0068] This embodiment provides a method for forming a pre-lithiated battery, the method comprising the following steps:

[0069] At an ambient temperature of 30°C, the lithium-ion battery after liquid injection (Preparation Example 1) was charged for the first time. The first charge was performed by charging at 0.03C to 10% SOC and then continuing to charge at 0.15C to 20% SOC.

[0070] Stop charging and place the battery cell at 50℃ for 12 hours.

[0071] At an ambient temperature of 42°C, a second charge is performed, which is a charge at 0.6C to 3.45V, at which the positive electrode active material undergoes delithiation.

[0072] Stop charging and place the battery cell at 49℃ for 13 hours.

[0073] At an ambient temperature of 64°C, a third charge is performed, which is a charge at 0.3C to 4.25V, at which the positive electrode lithium replenishment agent decomposes.

[0074] Stop charging and place the battery cell at 50℃ for 12 hours to complete the formation process.

[0075] The cells after the above formation are then injected with electrolyte a second time, sealed, and then subjected to 0.5P discharge capacity testing.

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 1 is that, after the first charge and before the second charge, it was not left to stand at 45°C for 12 hours. After the second charge and before the third charge, it was not left to stand at 45°C for 12 hours. Both the second and third charges were performed at an ambient temperature of 25°C. After the third charge, the standing time was changed to 48 hours.

[0078] Comparative Example 2

[0079] The difference between this comparative example and Example 1 is that the temperature of the third charge is adjusted to 45°C.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that it was not left to stand at 45°C for 12 hours after the second charge and before the third charge.

[0082] Comparative Example 4

[0083] The difference between this comparative example and Example 1 is that the temperature of the third charge is adjusted to 25°C and the third charge rate is adjusted to 0.05°C.

[0084] Performance testing:

[0085] (1) Observation of the negative electrode interface of the cell: After the cell has been fully charged, it is disassembled in the drying room and the surface of the negative electrode is observed to see if there are gray lithium spots. If there are no lithium spots, it is recorded as good.

[0086] (2) Calculate the charging specific capacity of the lithium replenishing agent LFO: Test the cell formation charging capacity to determine the charging specific capacity C2 of lithium iron phosphate. Determine the charging specific capacity C2 of the positive electrode active material based on the composition of the positive electrode active material. Calculate the charging specific capacity of the lithium replenishing agent LFO based on the cell formation charging capacity, the charging specific capacity of lithium iron phosphate, the mass of lithium iron phosphate in the cell (in g), the mass of the lithium replenishing agent in the cell (in g), the mass percentage of lithium iron phosphate in the cell (in %), and the mass percentage of the lithium replenishing agent LFO in the cell (in %). The calculation formula is as follows:

[0087] The specific charging capacity of the lithium replenishing agent LFO is calculated as (C1 - C2 × m1) / + m2, where C1 is the cell formation charging capacity, C2 is the specific charging capacity of lithium iron phosphate, m1 is the mass of lithium iron phosphate in the cell, and m2 is the mass of the lithium replenishing agent in the cell.

[0088] (3) Cyclic performance test: The cells after capacity division are charged and discharged in the range of 2.5-3.65V with a power of 0.5P (P=1024W) for 1000 cycles, and the energy retention rate compared with the initial energy is calculated after 1000 cycles.

[0089] The results are shown in Table 1.

[0090] Table 1

[0091] As shown in Table 1, the formation method of the present invention can achieve sufficient lithium replenishment effect, the lithium replenishment agent has high charging specific capacity, and can also effectively solve the problem of lithium deposition on the negative electrode surface. After the battery is fully charged and disassembled, the negative electrode interface of the cell is good and there are no lithium deposition spots, thus improving the cycle performance of the battery.

[0092] A comparison of Examples 1 and 2-3 shows that if the temperature of the third charge is too low (Example 2), the specific capacity of the lithium replenishment charge will decrease, and the energy retention rate after 1000 cycles will also decrease. If the temperature of the third charge is too high (Example 3), the specific capacity of the lithium replenishment charge will be basically the same, but the cycle performance will decrease slightly, possibly because the higher temperature will cause some degree of degradation to the cell interface.

[0093] A comparison between Example 1 and Comparative Example 1 shows that, since the charging was carried out at an ambient temperature of 25°C and no high-temperature settling was performed, the negative electrode sheet was not fully wetted, and some graphite active materials were not fully utilized. During charging, some lithium ions could not be embedded in the graphite in time, resulting in lithium deposition on the graphite negative electrode surface. The charging specific capacity and cycle performance of the lithium replenishing agent LFO both decreased.

[0094] The comparison between Example 1 and Comparative Example 2 shows that in the high-voltage region of lithium replenishment decomposition, increasing the temperature is beneficial to increasing the charging capacity of the lithium replenishment, thereby increasing the amount of pre-stored lithium in the negative electrode and improving cycle performance.

[0095] A comparison between Example 1 and Comparative Example 3 shows that, since this step did not involve standing, the wetting of the electrolyte deteriorated, leading to a deterioration of the cell interface. This could potentially cause lithium plating during the third charge, resulting in a decrease in cycle performance.

[0096] The comparison between Example 1 and Comparative Example 4 shows that due to the low temperature, the lithium replenishment material itself has poor rate performance. Although a smaller current was used, the decomposition reaction was insufficient, the lithium replenishment effect was poor, and the cycle performance was not significantly improved.

[0097] It should be noted that the above examples and comparative examples use lithium iron phosphate as the positive electrode active material, LFO as the lithium replenishing agent, and graphite as the negative electrode active material to prepare lithium-replenishing batteries and verify the formation method. However, they are not limited to the above-mentioned materials. Other positive electrode active materials (such as ternary materials), other lithium replenishing agents (such as LNO), and other negative electrode active materials (such as silicon) can also effectively improve the interface, enhance the lithium replenishment effect, and improve the battery performance.

[0098] The present invention has been illustrated with the above embodiments to explain the detailed method of the present invention. However, the present invention is not limited to the detailed method described above, that is, it does not mean that the present invention must rely on the detailed method described above to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for forming a pre-lithiated battery, characterized in that, The formation method includes the following steps: Perform a first charge on the post-injection lithium-supplemented battery to a preset SOC to form a SEI film; Perform a second charge to raise the voltage to V1, causing the positive active material to continue to de-lithiate, and then let it stand; Perform a third charge to raise the voltage to V2, where V2 is the cut-off voltage for the decomposition of the lithium-supplementing agent; Among them, the temperature of the first charge is T1, the temperature of the standing is T2, and the temperature of the third charge is T3, where T1 < T2 and T2 < T3; 20°C < T1 < 30°C; 40°C < T2 < 50°C; 50°C ≤ T3 ≤ 65°C; After the voltage rises to V1, the standing time is 6h to 12h; 3.4V < V1 < 3.65V; V2 is 4.05V to 4.3V.

2. The formation method of the pre-lithiated battery according to claim 1, characterized in that, The charge rate of the first charge is 0.02C to 0.3C.

3. The formation method of the pre-lithiated battery according to claim 1, characterized in that, The preset SOC is 10% to 50% SOC and does not include 50% SOC.

4. The formation method of the pre-lithiated battery according to claim 1, characterized in that, After the lithium-supplemented battery is charged to the preset SOC, stop charging and let it stand for 12h to 48h under the condition of 40°C to 50°C.

5. The formation method of the pre-lithiated battery according to claim 1, characterized in that, The charge rate of the second charge is 0.3C to 0.6C.

6. The formation method of the pre-lithiated battery according to claim 1, characterized in that, When the voltage rises to V1, the lithium-supplemented battery is charged to more than 80% SOC and less than or equal to 100% SOC.

7. The formation method of the pre-lithiated battery according to claim 1, characterized in that, The temperature of the second charge is 40°C to 50°C.

8. The formation method of the pre-lithiated battery according to claim 1, characterized in that, The charge rate of the third charge is 0.1C to 0.3C.

9. The formation method of the pre-lithiated battery according to claim 1, characterized in that, After the voltage rises to V2, stop charging and let the lithium-supplemented battery stand for 12h to 48h at 40°C to 50°C.

10. The formation method of the pre-lithiated battery according to claim 1, characterized in that, The post-injection lithium-supplemented battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The positive electrode plate includes a positive current collector and a positive electrode material layer provided on the surface of the positive current collector. The positive electrode material layer includes a positive active material and a lithium-supplementing agent.

11. The formation method of the pre-lithiated battery according to claim 10, characterized in that, The mass of the lithium-supplementing agent accounts for 0.5% to 5% of the mass of the positive electrode material layer.

12. A battery, characterized in that, The battery is prepared by the following method: After the post-injection lithium-supplemented battery is formed by the method described in any one of claims 1-11, perform secondary injection, seal, and capacity grading.

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