Formation Process of High-Voltage and High-Specific-Energy Soft-Pack Lithium-Ion Batteries

Abstract

The present invention provides a formation process for a high-voltage and high specific energy soft-pack lithium-ion battery, including: after vacuum injecting electrolyte into the battery, performing pre-sealing; performing primary high-temperature aging; performing multiple high-temperature target current formations, and after formation, performing high-temperature aging, degassing and re-sealing; performing 100% SOC full charge and discharge cycles; and finally performing high-temperature aging and degassing and final sealing. The above-mentioned formation process of the present invention is carried out under high-temperature conditions, which can improve the infiltration of the electrolyte, and at the same time can improve the formation efficiency. The formed SEI film is dense, uniform, stable and has a high conductivity. In addition, the 100% SOC full charge and discharge cycles can ensure the full progress of side reactions, thereby effectively improving the performance stability of the battery under high voltage, and alleviating the technical problems of the existing formation process, such as long time consumption, poor performance of the formed SEI film, and inability to ensure the full progress of side reactions.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion batteries, and in particular to a high-voltage and high-energy-density soft-pack lithium ion battery formation process. Background Art

[0002] In recent years, the electric vehicle industry has developed rapidly, and the number of electric vehicles has continued to grow. What restricts the development of electric vehicles is no longer the technical barriers of core components, but the development of driving range and supporting facilities. As the core component of electric vehicles, the energy density of lithium ions directly determines the vehicle's driving range. Increasing the specific energy of the battery, on the one hand, expands the gram capacity of the material, and on the other hand, increases the voltage of the battery. High-voltage system lithium-ion batteries have become the main development trend due to their advantages such as high energy, high safety, and low cost.

[0003] The charging voltage window of the high-voltage system has been gradually increased from the conventional 4.2V to 4.35V, 4.4V, and even higher. Due to the expansion of the voltage upper limit window, the oxidation performance of the positive electrode is enhanced, the side reactions increase, and the stability of the system (high temperature, cycle, safety, easy bulging, etc.) decreases. This puts higher requirements on the electrolyte, and special additives are often added to form a dense, uniform, and stable solid electrolyte (Solid Electrolyte Interface, referred to as SEI) film. Formation is an extremely important link in the manufacturing process of lithium-ion batteries. As the formation stage of SEI, the advantages and disadvantages of the formation process determine the film quality of the SEI film, which directly affects the battery's rate performance, high temperature stability, cycle performance, safety performance, etc.

[0004] At present, the conventional formation process adopts the method of placing the electrolyte at room temperature after injection, and then distributing the electrolyte to a certain SOC (generally SOC < 60%). Placing the electrolyte at room temperature is not conducive to the infiltration of the thick-coated and high-voltage solid electrode of the high-voltage and high-energy system; although the formation with a small current is conducive to the compactness of the SEI film, the electrolyte infiltration is poor, and the conductivity of the SEI film is large, and the formation time is long; the conventional low SOC formation is not conducive to the full conduction of the side reactions of the high-voltage system of the multifunctional additive.

[0005] In summary, the existing formation process consumes a long time, the formed SEI film has poor performance, and cannot ensure the full progress of side reactions. It is not suitable for the formation of high-voltage and high-energy-density soft-pack lithium-ion batteries. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a high-voltage and high-energy-density soft-pack lithium-ion battery formation process to alleviate the technical problems that the existing formation process consumes a long time, the formed SEI film has poor performance, and the side reactions cannot be fully guaranteed.

[0007] In a first aspect, the present invention provides a formation process for a high-voltage and high-specific-energy soft-pack lithium-ion battery, comprising:

[0008] (1) After vacuum injecting electrolyte into the battery, perform pre-sealing;

[0009] (2) Perform primary high-temperature aging;

[0010] (3) Perform multiple high-temperature target-current formations, and after formation, perform high-temperature aging and degassing and re-sealing. Among them, the target current includes: small current and large current;

[0011] (4) Perform 100% SOC full charge-discharge cycles;

[0012] (5) Perform final high-temperature aging, degassing and final sealing.

[0013] Further, the multiple high-temperature target-current formations in step (3) and, after formation, perform high-temperature aging, degassing and re-sealing, including:

[0014] (3.1) Perform primary high-temperature small-current formation;

[0015] (3.2) Perform secondary high-temperature aging, degassing and second sealing;

[0016] (3.3) Perform secondary high-temperature large-current formation;

[0017] (3.4) Perform tertiary high-temperature aging, degassing and third sealing.

[0018] Further, the temperature of the primary high-temperature aging in step (2) is 35°C to 80°C, and the aging time is 10h to 24h.

[0019] Further, the formation temperature of the primary high-temperature small-current formation in step (3.1) is 35°C to 70°C, the current is 0.02C to 0.1C, and the formation is carried out to 25% SOC to 30% SOC.

[0020] Further, the aging temperature in the secondary high-temperature aging in step (3.2) is 35°C to 70°C, and the aging time is 12h to 48h.

[0021] Further, the formation temperature of the secondary high-temperature large-current formation in step (3.3) is 35°C to 70°C, the current is 0.3C to 2C, and the formation is carried out to 60% SOC to 80% SOC.

[0022] Further, the aging temperature in the tertiary high-temperature aging in step (3.4) is 35°C to 70°C, and the aging time is 12h to 48h.

[0023] Further, the 100% SOC full charge-discharge cycles in step (4) are 3 - 5 times of constant-current and constant-voltage full charge-discharge cycles.

[0024] Further, in step (5), the aging temperature for the final high-temperature aging is 35°C to 70°C, and the aging time is 12h to 48h.

[0025] Further, in step (5), the sealing vacuum degree for degassing and final sealing is less than or equal to -92 KPa.

[0026] In the embodiment of the present invention, a formation process for a high-voltage and high-specific-energy soft-pack lithium-ion battery is provided, including: after vacuum injecting the battery with electrolyte, performing pre-sealing; performing primary high-temperature aging; performing multiple high-temperature target current formations, and after formation, performing high-temperature aging, degassing and re-sealing, where the target current includes: small current and large current; 100% SOC full charge and discharge cycle; final high-temperature aging, degassing and final sealing. Through the above description, it can be seen that the above formation process of the present invention is carried out under high-temperature conditions, which can improve the infiltration of the electrolyte, and at the same time can improve the formation efficiency. The formed SEI film is dense, uniform, stable and has a high conductivity. In addition, the 100% SOC full charge and discharge cycle can ensure the full progress of side reactions, thereby effectively improving the performance stability of the battery under high voltage, and alleviating the technical problems of the existing formation process that consumes a long time, the formed SEI film has poor performance, and the full progress of side reactions cannot be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a flowchart of the formation process for a high-voltage and high-specific-energy soft-pack lithium-ion battery provided by the embodiment of the present invention;

[0029] Figure 2 It is a flowchart of performing multiple high-temperature target current formations, and after formation, performing high-temperature aging and degassing and re-sealing provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0031] At present, the conventional formation process adopts normal temperature storage after liquid injection, and small current distribution formation is carried out until a certain SOC (generally SOC < 60%). The formation time consumption is long, the performance of the formed SEI film is poor, and the full progress of side reactions cannot be guaranteed.

[0032] Based on this, the formation process of the present invention is carried out under high temperature conditions, which can improve the infiltration of the electrolyte, and at the same time can improve the formation efficiency. The formed SEI film is dense, uniform, stable and has a high conductivity. In addition, 100% SOC full charge and discharge cycling can ensure the full progress of side reactions, thereby effectively improving the performance stability of the battery under high voltage.

[0033] The embodiments of the present invention will be further introduced below with reference to the accompanying drawings.

[0034] See Figure 1 , the formation process of the high-voltage and high-specific-energy soft-pack lithium-ion battery provided by the present invention sequentially includes the following steps:

[0035] (1) After vacuum injecting liquid into the battery, perform pre-sealing;

[0036] (2) Perform primary high-temperature aging;

[0037] (3) Perform multiple high-temperature target current formations, and after formation, perform high-temperature aging, degassing and re-sealing, where the target current includes: small current and large current;

[0038] (4) 100% SOC full charge and discharge cycling;

[0039] (5) Perform final high-temperature aging, degassing and final sealing.

[0040] In the above step (1), after vacuum injecting liquid into the baked battery, it needs to be placed in a vacuum state for 30 to 60 seconds, which can effectively discharge the air in the pores of the electrode sheet, facilitate the infiltration of the electrolyte into the electrode sheet, and the above pre-sealing refers to the initial sealing of the soft-pack lithium-ion battery after vacuum injecting liquid.

[0041] The inventor considered that the electrode core of the high-voltage and high-specific-energy soft-pack lithium-ion battery adopts a thick coating and high compaction design, and the electrolyte infiltration speed at normal temperature is slow and the infiltration effect is poor (it is possible that the electrolyte penetration is uneven). In the formation process of the present invention, the above step (2) adopts primary high-temperature aging. At high temperature, the viscosity of the electrolyte becomes smaller and the kinetics is accelerated, thereby improving the penetration force of the electrolyte (that is, the penetration is relatively fast), shortening the penetration and infiltration time, and thus improving the efficiency of the formation process; in addition, at high temperature, the electrolyte can also penetrate more uniformly, effectively improving the infiltration effect of the electrolyte.

[0042] The temperature of the first high-temperature aging in step (2) above is 35°C to 80°C (preferably 40°C to 50°C), and the aging time is 10h to 24h (preferably 15h to 20h).

[0043] Furthermore, the traditional forming process uses small-current forming. Small-current forming takes a long time and has low forming efficiency. Moreover, the SEI film obtained has too high a density, resulting in an increase in its conductivity and too low a shuttling efficiency of lithium ions. In the present invention, step (3) above uses multiple high-temperature target-current forming. Specifically, high-temperature small-current forming can be carried out first, and then high-temperature large-current forming. In such a combined forming method, during the small-current forming process, it is beneficial to form a dense SEI film, and large-current forming can accelerate the forming efficiency and improve the wettability and conductivity of the SEI film (that is, the SEI film also has a certain degree of looseness). That is to say, the combined use of the two forming modes is beneficial to form a uniform, stable and well-conductive SEI film, and can also shorten the forming cycle.

[0044] In addition, in step (3) of the present invention, after forming, high-temperature aging and degassing and resealing are carried out. Under high-temperature conditions, the aging process can promote the occurrence of side reactions in the battery. The formed SEI film has better stability at high temperatures and is not easily decomposed during subsequent use. After each forming and high-temperature aging, the process of degassing and resealing should be carried out to prevent the gas generated after each forming and aging from corroding the battery and thus affecting the performance of the battery.

[0045] In addition, in order to fully carry out the side reactions under high voltage during the forming process, the present invention adopts the 100% SOC full charge and discharge cycle in step (4) above, and at the same time carries out the final high-temperature aging in step (5), so that the side reactions under the high-voltage system are fully carried out, improving the high-temperature and cycle stability of the battery.

[0046] The following is a popular explanation of the full progress of side reactions: Since the battery will react at each voltage. For example, the battery will be used at 4.4V or 4.5V or higher voltages in the future. If the previous forming process does not eliminate the possible side reactions in these voltage states, when the battery is used at the above 4.4V or 4.5V or higher voltages later, the electrolyte in it may decompose, and impurities may also decompose. At this time, the battery will have problems. Therefore, in the previous forming process, it is necessary to fully consider the high-voltage system.

[0047] In addition, during the formation process of the soft-pack battery, an air bag needs to be left. During the formation process, if gas is generated by side reactions, the gas will be discharged into the air bag, and then the gas in the air bag will be pumped out. After that, the battery is formed and the process ends. However, if the side reactions do not proceed sufficiently during the formation process, when the battery enters the market for use, the air bag needs to be removed. In this way, during the use process, the gas generated by the side reactions under high voltage will cause the battery to bulge.

[0048] The above process of the present invention can ensure that during the formation process of the battery, the side reactions at high voltage proceed sufficiently. After the battery is formed, there will be no situation where the electrolyte decomposes or gas is generated due to some side reactions at high voltage not being activated, thereby causing the battery to fail.

[0049] In an embodiment of the present invention, a formation process for a high-voltage and high-specific-energy soft-pack lithium-ion battery is provided, including: after vacuum injecting the battery with electrolyte, performing pre-sealing; performing primary high-temperature aging; performing multiple high-temperature target current formations, and after the formation, performing high-temperature aging, degassing and re-sealing, where the target current includes: small current and large current; 100% SOC full charge and discharge cycle; final high-temperature aging, degassing and final sealing. Through the above description, it can be seen that the above formation process of the present invention is carried out under high-temperature conditions, which can improve the infiltration of the electrolyte, and at the same time can improve the formation efficiency. The formed SEI film is dense, uniform, stable, and has a high conductivity. In addition, the 100% SOC full charge and discharge cycle can ensure the sufficient progress of side reactions, thereby effectively improving the performance stability of the battery under high voltage, and alleviating the technical problems of the existing formation process, such as long time consumption, poor performance of the formed SEI film, and inability to ensure the sufficient progress of side reactions.

[0050] The above content briefly introduces the formation process of the high-voltage and high-specific-energy soft-pack lithium-ion battery of the present invention. The following will describe the specific content involved in detail.

[0051] In an alternative embodiment of the present invention, referring to Figure 2 , step (3) multiple high-temperature target current formations, and after the formation, performing high-temperature aging, degassing and re-sealing, specifically includes:

[0052] (3.1) Performing a primary high-temperature small current formation;

[0053] (3.2) Performing a secondary high-temperature aging, degassing and second sealing;

[0054] (3.3) Performing a secondary high-temperature large current formation;

[0055] (3.4) Performing a tertiary high-temperature aging, degassing and third sealing.

[0056] In the above step (3.1), the formation temperature for the first high-temperature and small-current formation is 35°C to 70°C (preferably 45°C to 55°C), the current is 0.02C to 0.1C (preferably 0.02C to 0.05C), and the formation is carried out until 25% SOC to 30% SOC.

[0057] In step (3.2), the aging temperature for the second high-temperature aging is 35°C to 70°C (preferably 40°C to 50°C), and the aging time is 12h to 48h (preferably about 24h).

[0058] In step (3.3), the formation temperature for the second high-temperature and large-current formation is 35°C to 70°C (preferably 45°C to 55°C), the current is 0.3C to 2C, and the formation is carried out until 60% SOC to 80% SOC.

[0059] In step (3.4), the aging temperature for the third high-temperature aging is 35°C to 70°C (preferably 40°C to 50°C), and the aging time is 12h to 48h (preferably about 24h).

[0060] It can be seen that in the formation process of the present invention, the formation current is set in two stages: the first stage (25% SOC to 30% SOC), which is the main stage for the formation of the SEI film. Using a small current for slow charging (i.e., formation) is beneficial to the formation of a dense SEI film; the second stage (60% SOC to 80% SOC), using a large current greater than 0.3C for fast charging (conventional formation currents are all less than 0.2C) is beneficial to improving the wettability and conductivity of the SEI film. The combined use of the two charging modes (i.e., the two formation modes) is beneficial to the formation of a uniform, stable, and well-conductive SEI film, and can also shorten the formation cycle.

[0061] It should be noted that the multiple high-temperature target current formation of the present invention is not limited to the process of the above steps (3.1) to (3.4). It can also be one small-current formation, one large-current formation, then one small-current formation, and then one large-current formation. It can also be other multiple high-temperature target formation methods. The specific embodiments of the present invention do not limit the above multiple high-temperature target formation methods.

[0062] The inventor considered that the high-voltage system has higher activity at high temperatures than conventional-voltage batteries, and its performance is more likely to decay. In the above steps (3.1) to (3.4) of the present invention, heating formation is adopted, and high-temperature aging is carried out simultaneously. The formed SEI film has better stability at high temperatures and is not easily decomposed. In addition, gas is generated to varying degrees in different SOC interval charging sections. The present invention adopts high-temperature formation and aging, which can effectively reduce the gas solubility, and degassing is carried out in a timely manner after each high-temperature aging, which can improve the formation exhaust and formation interface problems.

[0063] In an alternative embodiment of the present invention, the 100% SOC full charge and discharge cycle in step (4) is a constant current and constant voltage full charge and discharge cycle for 3 - 5 times.

[0064] Specifically, perform constant current and constant voltage full charge and discharge at 0.5C - 2C for 3 - 5 cycles. Charge at a constant current until the upper limit voltage, and then charge at a constant voltage until the current reaches 0.05C, indicating a full charge.

[0065] In an alternative embodiment of the present invention, the aging temperature for the final high - temperature aging in step (5) is 35°C - 70°C (preferably 40°C - 50°C), and the aging time is 12h - 48h (preferably about 24 hours).

[0066] The present invention uses high - voltage full charge formation and high - temperature aging simultaneously, which is beneficial for the full progress of side reactions under a high - voltage system, and improves the high - temperature and cycle stability of the battery.

[0067] In an alternative embodiment of the present invention, the sealing vacuum degree for degassing and final sealing in step (5) is less than or equal to - 92KPa.

[0068] For high - voltage system battery cells, a high charging upper - limit voltage means more detachment of the positive electrode, unstable structure, and thus the SEI film is damaged; at the same time, a high positive - electrode potential means that the positive electrode has strong oxidizing properties, which is likely to cause oxidation and decomposition of the electrolyte. The present invention is mainly aimed at the design and performance characteristics of high - voltage and high - specific - energy batteries, such as difficult infiltration, high activity, and low stability. Through processes such as slow charging and fast charging at high temperature, high - temperature aging, segmented current, 100% SOC high - voltage full charge, and degassing at each step, a dense, uniform, and stable SEI film is formed, and at the same time, sufficient electrochemical reactions are carried out, effectively improving the performance stability of the battery under high voltage.

[0069] In summary, the process of the present invention fully considers the design and performance characteristics of high - voltage and high - specific - energy soft - package batteries, effectively optimizes the formation of the SEI film, ensures the full progress of side reactions, and effectively improves the capacity, high - temperature performance, cycle performance, safety, and consistency of the battery. At the same time, the process of the present invention is simple, easy to control, and convenient for production, providing a feasible method for the efficient formation of high - voltage and high - specific - energy batteries.

[0070] For the above - mentioned scheme, the present application is further illustrated through the following specific application examples and experimental comparisons.

[0071] Example 1

[0072] In this example, the following formation processes are sequentially performed on the baked high - voltage and high - specific - energy soft - package lithium - ion battery cells:

[0073] After vacuum injection of the electrolyte, perform pre - sealing;

[0074] Perform primary high - temperature aging;

[0075] Primary high-temperature and small-current formation;

[0076] Secondary high-temperature aging and degassing and second sealing;

[0077] Secondary high-temperature and large-current formation;

[0078] Tertiary high-temperature aging and degassing and third sealing;

[0079] Normal-temperature 0% - 100% SOC, full charge and discharge cycling;

[0080] 100% SOC final high-temperature aging and degassing and final sealing;

[0081] In this embodiment, the temperature of the primary high-temperature aging is 45°C, and the aging time is 10 h.

[0082] In the primary high-temperature and small-current formation process, the formation temperature is 40°C, the charging current is 0.05C, the charging time is 2 h, the 0.1C charging time is 2 h, and it is charged to 30% SOC;

[0083] In the secondary high-temperature aging process, the aging temperature is 40°C, and the aging time is 24 h;

[0084] In the secondary high-temperature and large-current formation process, the formation temperature is 40°C, the charging current is 0.3C, the charging time is 1 h, and it is charged to 80% SOC;

[0085] In the tertiary high-temperature aging process, the aging temperature is 40°C, and the aging time is 24 h;

[0086] In the normal-temperature 0% - 100% SOC, full charge and discharge cycling process, the charge and discharge current is 1C, and the charge and discharge cut-off voltage is 2.75 - 4.4V;

[0087] In the 100% SOC final high-temperature aging process, the aging temperature is 40°C, and the aging time is 24 h;

[0088] In the pre-sealing, degassing and final-sealing processes, the vacuum degree is set to -94 KPa.

[0089] Comparative Example 1

[0090] In this example, the following formation processes are sequentially performed on the high-voltage and high-specific-energy soft-pack lithium-ion battery cells after baking:

[0091] After vacuum injection of electrolyte, pre-sealing is carried out;

[0092] Normal-temperature aging;

[0093] Small-current normal-temperature formation;

[0094] Vacuum pumping;

[0095] High-temperature aging;

[0096] Final sealing after air extraction.

[0097] In this embodiment, the normal temperature aging temperature is 25 °C, and the aging time is 24 h.

[0098] In the small current normal temperature formation process, the charging current is 0.05C, the charging time is 1 h, the 0.1C charging time is 1 h, and it is charged to 60% SOC at 0.2C;

[0099] In the high temperature aging process, the aging temperature is 35 °C, and the aging time is 48 h.

[0100] In the pre-sealing, air extraction and final sealing processes, the vacuum degree is set to -94 KPa.

[0101] The batteries obtained after formation according to the formation processes of Example 1 and Comparative Example 1 were respectively subjected to high temperature cycle tests (charge and discharge cut-off voltages 2.8 - 4.4 V, charge and discharge rate 1C, cycle test until the discharge capacity is equal to 80% of the initial capacity), and the results are as follows:

[0102] Example Comparative Example Cycle life ≥1000 times ≥850 times

[0103] As can be seen from the above table, the present invention can effectively improve the high temperature cycle performance of high voltage and high specific energy batteries.

[0104] The batteries obtained after formation according to the formation processes of Example 1 and Comparative Example 1 were respectively subjected to rate discharge tests, and the discharge capacity percentages at different rates are as follows:

[0105] 0.33C 1C 2C Example 100％ 93％ 90％ Comparative Example 100％ 92％ 88％

[0106] As can be seen from the above table, the present invention can improve the rate discharge performance of high voltage and high specific energy batteries.

[0107] The batteries obtained after formation according to the formation processes of Example 1 and Comparative Example 1 were respectively subjected to high temperature storage tests (at room temperature, the battery was adjusted to 97% SOC and placed at 45 °C for 30 days, discharged at 1C to 2.8 V at room temperature, recorded as the residual capacity; then at room temperature, a standard charge and discharge was performed once, and the discharge capacity was recorded as the recovery capacity), and the results are as follows:

[0108] Example Comparative Example Charge retention rate ≥90％ ≥87％ Capacity recovery rate ≥98％ ≥95％

[0109] As can be seen from the above table, the present invention can effectively improve the high temperature storage performance of high voltage and high specific energy batteries.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A formation process for a high-voltage and high specific energy soft-pack lithium-ion battery, characterized in that Including: (1) After vacuum filling the battery, perform pre-sealing; (2) Perform primary high-temperature aging; (3) Perform multiple high-temperature formation with target currents, and after each formation, perform high-temperature aging, degassing and re-sealing. Among them, the target currents include: small current and large current; (4) 100% SOC full charge and discharge cycle; (5) Perform final high-temperature aging, degassing and final sealing; Among them, the 100% SOC full charge and discharge cycle in step (4) is to perform constant current and constant voltage full charge and discharge cycles 3 - 5 times; Among them, step (3) of performing multiple high-temperature formation with target currents, and after formation, performing high-temperature aging, degassing and re-sealing, includes: (3.1) Perform primary high-temperature small current formation; (3.2) Perform secondary high-temperature aging, degassing and second sealing; (3.3) Perform secondary high-temperature large current formation; (3.4) Perform tertiary high-temperature aging, degassing and third sealing; Among them, in step (3.1), the formation temperature of the primary high-temperature small current formation is 35°C to 70°C, the current is 0.02C to 0.1C, and the formation is carried out to 25% SOC to 30% SOC; Among them, in step (3.3), the formation temperature of the secondary high-temperature large current formation is 35°C to 70°C, the current is 0.3C to 2C, and the formation is carried out to 60% SOC to 80% SOC; Among them, the temperature of the primary high-temperature aging in step (2) is 35°C to 80°C; Among them, the aging temperature in the secondary high-temperature aging in step (3.2) is 35°C to 70°C; Among them, the aging temperature in the tertiary high-temperature aging in step (3.4) is 35°C to 70°C; Among them, the aging temperature of the final high-temperature aging in step (5) is 35°C to 70°C.

2. The formation process of the high-voltage and high specific energy soft-pack lithium-ion battery according to claim 1, characterized in that, The aging time in step (2) is 10h to 24h.

3. The formation process of the high-voltage and high specific energy soft-pack lithium-ion battery according to claim 1, characterized in that, The aging time in step (3.2) is 12h to 48h.

4. The formation process of the high-voltage and high specific energy soft-pack lithium-ion battery according to claim 1, wherein The aging time in step (3.4) is 12h to 48h.

5. The formation process of the high-voltage and high-specific-energy soft-pack lithium-ion battery according to claim 1, characterized in that, The aging time in step (5) is 12h to 48h.

6. The formation process of the high-voltage and high-specific-energy soft-pack lithium-ion battery according to claim 1, wherein The sealing vacuum degree of degassing and final sealing in step (5) is less than or equal to -92KPa.

Images