Preparation method of battery and battery

Abstract

The invention provides a preparation method of a battery and the battery. The preparation method of the battery comprises the following steps: forming a cell; carrying out infiltration treatment on the battery cell; the step of carrying out infiltration treatment on the battery cell comprises the substeps of carrying out first infiltration treatment and second infiltration treatment on the battery cell alternately for multiple times; wherein the temperature of the first infiltration treatment is higher than that of the second infiltration treatment; charging the battery cell for multiple times; in the process of multiple times of charging processing, the environment negative pressure value of the next time of charging processing is smaller than or equal to the environment negative pressure value of the previous time of charging processing. The reliability of the battery is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a method for preparing a battery and a battery. Background Art

[0002] With the proposal of the carbon neutrality goal, electrochemical energy storage and electric vehicles have developed rapidly in recent years. In the field of electrochemical energy storage and electric vehicles, lithium batteries have gradually become the mainstream of the market with their advantages of high energy density, long cycle life and moderate cost. Lithium batteries include power batteries and energy storage batteries. At present, the total stock of power batteries and energy storage batteries in the world has exceeded 1.5TWh, and the total annual shipments are greater than 500GWh.

[0003] The battery cells in the related technology are designed towards high surface density and high compaction density, which has great advantages in improving the energy density of lithium batteries and reducing costs. However, in the process of forming lithium batteries, the electrolyte has poor wetting effect on the battery cells; during the first charge and discharge process of lithium batteries, the interface film (SE I film) formed by the reaction between the electrode material and the electrolyte at the solid-liquid interface is of poor quality, resulting in poor reliability of lithium batteries. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to overcome the defect of poor reliability of batteries in the related art.

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a battery, comprising: forming a battery cell; performing an infiltration treatment on the battery cell; the infiltration treatment on the battery cell comprises: performing a first infiltration treatment and a second infiltration treatment on the battery cell alternately for multiple times; wherein the temperature of the first infiltration treatment is greater than the temperature of the second infiltration treatment; performing a charging treatment on the battery cell for multiple times; during the multiple charging treatments, the environmental negative pressure value of the latter charging treatment is less than or equal to the environmental negative pressure value of the previous charging treatment.

[0006] Optionally, performing the wetting treatment on the battery cell includes: performing the first wetting treatment on the battery cell N times; performing the second wetting treatment on the battery cell N-1 times; N is an integer greater than or equal to 2.

[0007] Optionally, the temperature of the first infiltration treatment is 40°C to 50°C; the temperature of the second infiltration treatment is 15°C to 25°C.

[0008] Optionally, the battery cell is charged for 3 or more times.

[0009] Optionally, performing the charging treatment on the battery cell multiple times includes: performing a first charging treatment, a second charging treatment and a third charging treatment on the battery cell in sequence; wherein the environmental negative pressure value of the second charging treatment is equal to the environmental negative pressure value of the first charging treatment, and the environmental negative pressure value of the third charging treatment is less than the environmental negative pressure value of the second charging treatment.

[0010] Optionally, the method further includes: performing a fourth charging process on the battery cell; wherein the environmental negative pressure value of the fourth charging process is less than or equal to the environmental negative pressure value of the third charging process.

[0011] Optionally, the environmental negative pressure value of the first charging treatment is -35Kpa~-45Kpa; the environmental negative pressure value of the second charging treatment is -35Kpa~-45Kpa; the environmental negative pressure value of the third charging treatment is -70Kpa~-80Kpa; and the environmental negative pressure value of the fourth charging treatment is -70Kpa~-80Kpa.

[0012] Optionally, during multiple charging treatments, the rate of the subsequent charging treatment is greater than or equal to the rate of the previous charging treatment; when the battery cell is subjected to multiple charging treatments, including: sequentially performing a first charging treatment, a second charging treatment, a third charging treatment and a fourth charging treatment on the battery cell, the rate of the first charging treatment is 0.01C to 0.02C, the rate of the second charging treatment is less than or equal to 0.025C, the rate of the third charging treatment is less than or equal to 0.1C, and the rate of the fourth charging treatment is less than or equal to 0.15C.

[0013] Optionally, the method further includes: after the battery cell is subjected to the immersion treatment and before the battery cell is subjected to the multiple charging treatments, the battery cell is subjected to a static treatment; the temperature of the static treatment is 15°C to 25°C, and the duration is 4h to 6h.

[0014] The present invention also provides a battery, which is prepared by the battery preparation method of the present invention.

[0015] The technical solution of the present invention has the following technical effects:

[0016] The preparation method of the battery provided by the technical solution of the present invention uses an electrolyte to perform an infiltration treatment on the battery core. Since the temperature of the first infiltration treatment is greater than the temperature of the second infiltration treatment, when the battery core is subjected to the first infiltration treatment, the battery core expands, the viscosity coefficient of the electrolyte is small, and the flow rate of the electrolyte is fast, which can increase the infiltration rate of the electrolyte into the battery core; when the battery core is subjected to the second infiltration treatment, the battery core shrinks, the viscosity coefficient of the electrolyte is relatively large, and the flow rate of the electrolyte is relatively slow, which can compensate for the internal infiltration of the battery core caused by the fast flow rate of the electrolyte in the first infiltration treatment. The difference in the local concentration of the electrolyte, therefore, performing multiple alternating first and second infiltration treatments on the battery cell can improve the electrolyte infiltration effect on the battery cell; in the process of multiple charging treatments on the battery cell, setting the environmental negative pressure value of the latter charging treatment to be less than or equal to the environmental negative pressure value of the previous charging treatment can prevent the accumulation of gas generated by the reaction between the electrode material and the electrolyte at the solid-liquid interface during the charging process, and discharge the gas in time, thereby improving the density of the interface film formed by the reaction between the electrode material and the electrolyte and reducing the impedance of the interface film. In summary, the reliability of the battery is improved.

[0017] The present invention also provides a battery, which is prepared by the method for preparing the battery of the present invention. Based on the improvement of battery reliability, the energy density of the battery is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A flow chart of a method for preparing a battery provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] An embodiment of the present invention provides a method for preparing a battery, referring to Figure 1 ,include:

[0025] S1: forming a battery cell;

[0026] S2: performing an immersion treatment on the battery cell; performing an immersion treatment on the battery cell comprises: performing a plurality of alternating first immersion treatments and second immersion treatments on the battery cell; wherein the temperature of the first immersion treatment is greater than the temperature of the second immersion treatment;

[0027] S3: performing multiple charging processes on the battery cell; during the multiple charging processes, the environmental negative pressure value of the subsequent charging process is less than or equal to the environmental negative pressure value of the previous charging process.

[0028] In this embodiment, the battery cell is treated with electrolyte. Since the temperature of the first treatment is higher than the temperature of the second treatment, when the battery cell is treated with the first treatment, the battery cell expands, the viscosity coefficient of the electrolyte is small, and the flow rate of the electrolyte is fast, which can improve the rate of electrolyte infiltration into the battery cell; when the battery cell is treated with the second treatment, the battery cell shrinks, the viscosity coefficient of the electrolyte is relatively large, and the flow rate of the electrolyte is relatively slow, which can make up for the difference in local concentration of the electrolyte inside the battery cell caused by the fast flow rate of the electrolyte in the first treatment. Therefore, the battery cell is treated with the first treatment and the second treatment alternately for multiple times, which can improve the infiltration effect of the electrolyte on the battery cell; in the process of multiple charging treatments of the battery cell, the environmental negative pressure value of the latter charging treatment is set to be less than or equal to the environmental negative pressure value of the previous charging treatment, which can prevent the accumulation of gas generated by the reaction of the electrode material and the electrolyte at the solid-liquid interface during the charging process, and discharge the gas in time, thereby improving the density of the interface film formed by the reaction of the electrode material and the electrolyte. Reduce the impedance of the interface film. In summary, the reliability of the battery is improved.

[0029] In one embodiment, the temperature of the first infiltration treatment is 40°C to 50°C, for example, 40°C, 45°C or 50°C. If the temperature of the first infiltration treatment is less than 40°C, the effect of increasing the infiltration rate of the electrolyte to the inside of the battery cell is weak; if the temperature of the first infiltration treatment is greater than 50°C, the components of the electrolyte are easily decomposed, and the increased energy consumption leads to high costs. In summary, the temperature of the first infiltration treatment is 40°C to 50°C, which can better take into account the requirements of high infiltration rate of the electrolyte to the inside of the battery cell, good infiltration effect and low manufacturing cost. It should be noted that in other embodiments, the temperature of the first infiltration treatment is not limited to this.

[0030] In one embodiment, the temperature of the second wetting treatment is 15°C to 25°C, for example, 15°C, 20°C or 25°C. If the temperature of the second wetting treatment is less than 15°C, the effect of compensating for the difference in local concentration of the electrolyte inside the battery cell is weak; if the temperature of the second wetting treatment is greater than 25°C, the energy consumption increases, resulting in high costs. In summary, the temperature of the second wetting treatment is 15°C to 25°C, and the temperature of the second wetting treatment is room temperature, which can better take into account the requirements of good wetting effect of the electrolyte on the inside of the battery cell and low manufacturing cost. It should be noted that in other embodiments, the temperature of the second wetting treatment is not limited to this.

[0031] In one embodiment, performing the soaking treatment on the battery cell includes: performing the first soaking treatment on the battery cell N times; performing the second soaking treatment on the battery cell N-1 times; N is an integer greater than or equal to 2. That is, during the process of performing the first soaking treatment and the second soaking treatment alternately multiple times on the battery cell, the second soaking treatment is performed between adjacent first soaking treatments.

[0032] In this embodiment, N is an integer equal to 2. The infiltration treatment of the battery cell includes: performing a first infiltration treatment on the battery cell for the first time; then, performing a second infiltration treatment on the battery cell; after performing the second infiltration treatment on the battery cell, performing a second first infiltration treatment on the battery cell. When N is an integer equal to 2, the number of times the first infiltration treatment and the second infiltration treatment are performed on the battery cell is small, which improves the infiltration effect of the electrolyte on the battery cell and reduces the production cost.

[0033] In other embodiments, N is an integer greater than 2, and the number of times the first immersion treatment is performed on the battery cell and the number of times the second immersion treatment is performed on the battery cell can be selected according to actual needs.

[0034] In one embodiment, the duration of the latter first infiltration treatment is greater than or equal to 0.8 times the duration of the previous first infiltration treatment. In this embodiment, when N is an integer equal to 2, the duration of the second first infiltration treatment is greater than or equal to 0.8 times the duration of the first first infiltration treatment. The duration of the second first infiltration treatment and the duration of the first first infiltration treatment can be selected according to actual needs.

[0035] In one embodiment, the duration of the first first infiltration treatment is 28.8h to 43.2h, for example, 28.8h, 30h, 34h, 36h, 40h or 43.2h. If the duration of the first first infiltration treatment is less than 28.8h, the effect of improving the wetting effect of the electrolyte on the battery cell is weak; if the duration of the first first infiltration treatment is greater than 43.2h, it will lead to low production efficiency. In summary, the duration of the first first infiltration treatment is 28.8h to 43.2h, which can better take into account the requirements of good wetting effect of the electrolyte on the inside of the battery cell and high production efficiency. It should be noted that in other embodiments, the duration of the first first infiltration treatment is not limited to this.

[0036] In one embodiment, the duration of the second first infiltration treatment is 19.2h to 28.2h, for example, 19.2h, 20h, 22h or 24h. If the duration of the second first infiltration treatment is less than 19.2h, the effect of improving the wetting effect of the electrolyte on the battery cell is weak; if the duration of the second first infiltration treatment is greater than 24h, it will lead to low production efficiency. In summary, the duration of the second first infiltration treatment is 19.2h to 28.2h, which can better take into account the requirements of good wetting effect of the electrolyte on the inside of the battery cell and high production efficiency. It should be noted that in other embodiments, the duration of the second first infiltration treatment is not limited to this.

[0037] In one embodiment, the duration of the second infiltration treatment is 9.6h to 14.4h, for example, 9.6h, 10h, 12h or 14.4h. If the duration of the second infiltration treatment is less than 9.6h, the effect of compensating for the difference in local concentration of the electrolyte inside the battery cell is weak; if the duration of the second infiltration treatment is greater than 14.4h, it will lead to low production efficiency. In summary, the duration of the second infiltration treatment is 9.6h to 14.4h, which can better take into account the requirements of good infiltration effect of the electrolyte on the inside of the battery cell and high production efficiency. It should be noted that in other embodiments, the duration of the second infiltration treatment is not limited to this.

[0038] In one embodiment, the number of times the battery cell is charged is greater than or equal to 3 times. The stability of the interface film formed by the reaction between the electrode material and the electrolyte at the solid-liquid interface can be improved. It should be noted that the number of times the battery cell is charged can be selected according to actual needs, and can be 3 times or 4 times, but is not limited thereto.

[0039] In one embodiment, performing multiple charging treatments on the battery cell includes: performing a first charging treatment, a second charging treatment, and a third charging treatment on the battery cell in sequence; wherein the environmental negative pressure value of the second charging treatment is equal to the environmental negative pressure value of the first charging treatment, and the environmental negative pressure value of the third charging treatment is less than the environmental negative pressure value of the second charging treatment. Performing the first charging treatment on the battery cell can activate the battery cell and remove impurities inside the battery cell at the same time. During the second charging treatment on the battery cell, the electrode material and the electrolyte react at the solid-liquid interface to gradually form an interface film. Therefore, the environmental negative pressure value of the second charging treatment can be equal to the environmental negative pressure value of the first charging treatment; the environmental negative pressure value of the third charging treatment is set to be less than the environmental negative pressure value of the second charging treatment, so that the gas generated by the reaction between the electrode material and the electrolyte at the solid-liquid interface in the second charging treatment is discharged.

[0040] In one embodiment, the preparation method of the battery further includes: performing a fourth charging process on the battery cell; wherein the environmental negative pressure value of the fourth charging process is less than or equal to the environmental negative pressure value of the third charging process. The accumulation of gas generated by the reaction between the electrode material and the electrolyte at the solid-liquid interface during the third charging process can be prevented, and the gas can be discharged in time, further improving the density of the interface film formed by the reaction between the electrode material and the electrolyte.

[0041] It should be noted that the ambient negative pressure value is negative in value. The smaller the ambient negative pressure value, the greater the absolute value of the ambient negative pressure, and the greater the ambient vacuum degree.

[0042] In one embodiment, the environmental negative pressure value of the first charging treatment is -35Kpa to -45Kpa, for example, -35Kpa, -40Kpa or -45Kpa. If the environmental negative pressure value of the first charging treatment is greater than -35Kpa, the battery cell activation effect is poor; if the environmental negative pressure value of the first charging treatment is less than -45Kpa, the environmental vacuum degree inside the battery cell is too large, which may easily cause electrolyte overflow and affect the charging performance of the battery cell. In summary, the environmental negative pressure value of the first charging treatment is -35Kpa to -45Kpa, which can relatively well balance the requirements of good battery cell activation effect and high charging performance. It should be noted that in other embodiments, the environmental negative pressure value of the first charging treatment is not limited to this.

[0043] In one embodiment, the environmental negative pressure value of the second charging treatment is -35Kpa to -45Kpa, for example, -35Kpa, -40Kpa or -45Kpa. If the environmental negative pressure value of the second charging treatment is greater than -35Kpa, the probability of the electrode material and the electrolyte reacting at the solid-liquid interface is small, and the effect of improving the density of the interface film is weak; if the environmental negative pressure value of the second charging treatment is less than -45Kpa, the environmental vacuum degree inside the battery cell is too large, which may easily cause the electrolyte to overflow and affect the charging performance of the battery cell. In summary, the environmental negative pressure value of the second charging treatment is -35Kpa to -45Kpa, which can relatively well take into account the requirements of high density of the interface film and high charging performance. It should be noted that in other embodiments, the environmental negative pressure value of the second charging treatment is not limited to this.

[0044] In one embodiment, the environmental negative pressure value of the third charging treatment is -70Kpa to -80Kpa, for example, -70Kpa, -75Kpa or -80Kpa. If the environmental negative pressure value of the third charging treatment is greater than -70Kpa, the ability to discharge the gas generated by the reaction between the electrode material and the electrolyte at the solid-liquid interface is weak; if the environmental negative pressure value of the third charging treatment is less than -80Kpa, the environmental vacuum degree inside the battery cell is too large, which may easily cause the electrolyte to overflow and affect the charging performance of the battery cell. In summary, the environmental negative pressure value of the third charging treatment is -70Kpa to -80Kpa, which can meet the high requirements of charging performance. It should be noted that in other embodiments, the environmental negative pressure value of the third charging treatment is not limited to this.

[0045] In one embodiment, the environmental negative pressure value of the fourth charging treatment is -70Kpa to -80Kpa, for example, -70Kpa, -75Kpa or -80Kpa. If the environmental negative pressure value of the fourth charging treatment is greater than -70Kpa, the ability to discharge the gas generated by the reaction of the electrode material and the electrolyte at the solid-liquid interface is weak; if the environmental negative pressure value of the fourth charging treatment is less than -80Kpa, the environmental vacuum degree inside the battery cell is too large, which may easily cause the electrolyte to overflow and affect the charging performance of the battery cell. In summary, the environmental negative pressure value of the fourth charging treatment is -70Kpa to -80Kpa, which can meet the high charging performance requirements. It should be noted that in other embodiments, the environmental negative pressure value of the third charging treatment is not limited to this.

[0046] In one embodiment, during multiple charging processes, the rate of the subsequent charging process is greater than or equal to the rate of the previous charging process. Each charging process adopts a constant current charging method, that is, the rate of each charging process remains unchanged during each charging process, which can improve the thickness consistency of the interface film formed by the reaction between the electrode material and the electrolyte.

[0047] In one embodiment, the ratio of the first charging treatment is 0.01C to 0.02C, for example, 0.01C, 0.015C or 0.02C. The ratio of the first charging treatment remains unchanged during the first charging treatment, and the battery cell is activated and impurities inside the battery cell are removed by the first charging treatment. If the ratio of the first charging treatment is less than 0.01C, the battery cell activation effect is poor; if the ratio of the first charging treatment is greater than 0.02C, the electrode material and the electrolyte react too violently at the solid-liquid interface, and the effect of improving the thickness consistency of the interface film is poor.

[0048] In one embodiment, the temperature of the first charging treatment is 40° C. to 50° C., for example, 40° C., 45° C. or 50° C. The duration of the first charging treatment is 24 min to 36 min., for example, 24 min, 28 min, 30 min, 34 min or 36 min. The duration and temperature of the first charging treatment can be selected according to actual needs.

[0049] In one embodiment, the rate of the second charging treatment is less than or equal to 0.025C. The rate of the second charging treatment remains unchanged during the second charging treatment, and the second charging treatment causes the electrode material to react with the electrolyte to form an interface film. Preferably, the rate of the second charging treatment is greater than the rate of the first charging treatment, and the rate of the second charging treatment is less than or equal to 0.025C, which is useful for shortening the charging time and improving the charging efficiency; at the same time, it avoids excessive reaction between the electrode material and the electrolyte at the solid-liquid interface and improves the thickness consistency of the interface film.

[0050] In one embodiment, the temperature of the second charging process is 40° C. to 50° C., for example, 40° C., 45° C. or 50° C. The duration of the second charging process is 56 min to 84 min, for example, 56 min, 67 min, 70 min, 75 min or 84 min. The duration and temperature of the second charging process can be selected according to actual needs.

[0051] In one embodiment, the rate of the third charging treatment is less than or equal to 0.1C. The rate of the third charging treatment remains unchanged during the third charging treatment, and the third charging treatment accelerates the reaction between the electrode material and the electrolyte to form an interface film. Preferably, the rate of the third charging treatment is greater than the rate of the second charging treatment, and the rate of the third charging treatment is less than or equal to 0.1C, which is useful for shortening the charging time and improving the charging efficiency; at the same time, it avoids excessive reaction between the electrode material and the electrolyte at the solid-liquid interface and improves the thickness consistency of the interface film.

[0052] In one embodiment, the temperature of the third charging treatment is 40° C. to 50° C., for example, 40° C., 45° C. or 50° C. The duration of the third charging treatment is 144 min to 216 min, for example, 144 min, 160 min, 180 min, 200 min or 210 min. The duration and temperature of the third charging treatment can be selected according to actual needs.

[0053] In one embodiment, the ratio of the fourth charging treatment is less than or equal to 0.15C. The ratio of the fourth charging treatment remains unchanged during the fourth charging treatment, and the fourth charging treatment can form a stable interface film. Preferably, the ratio of the fourth charging treatment is greater than the ratio of the third charging treatment, and the ratio of the fourth charging treatment is less than or equal to 0.15C, which can shorten the charging time and improve the charging efficiency; at the same time, improve the thickness consistency of the interface film.

[0054] In one embodiment, the temperature of the fourth charging process is 40° C. to 50° C., for example, 40° C., 45° C. or 50° C. The duration of the fourth charging process is 32 min to 48 min., for example, 32 min, 35 min, 40 min, 45 min or 48 min. The duration and temperature of the fourth charging process can be selected according to actual needs.

[0055] In one embodiment, the method for preparing the battery further includes: after the battery cell is wetted and before the battery cell is charged multiple times, the battery cell is left to stand, which can further improve the contact between the electrode material and the electrolyte and enhance the reliability of the battery.

[0056] In other embodiments, after the battery cell is subjected to the wetting treatment, the battery cell is subjected to multiple charging treatments without the need for the static treatment.

[0057] In one embodiment, the temperature of the static treatment is 15°C to 25°C, for example, 15°C, 20°C or 25°C. If the temperature of the static treatment is less than 15°C, the effect of improving the contact between the electrode material and the electrolyte is weak; if the temperature of the static treatment is greater than 25°C, the production efficiency is reduced due to too long a static treatment. In summary, the temperature of the static treatment is 15°C to 25°C, and the temperature of the static treatment is room temperature, which can better take into account the contact effect between the electrode material and the electrolyte and the high production efficiency requirements. It should be noted that in other embodiments, the temperature of the static treatment is not limited to this.

[0058] In one embodiment, the duration of the static treatment is 4h to 6h, for example, 4h, 5h or 6h. If the duration of the static treatment is less than 4h, the effect of improving the contact between the electrode material and the electrolyte is weak; if the duration of the static treatment is greater than 6h, the production efficiency is reduced due to the long static treatment. In summary, the duration of the static treatment is 4h to 6h, which can better take into account the contact effect between the electrode material and the electrolyte and the high production efficiency requirements. It should be noted that in other embodiments, the duration of the static treatment is not limited to this.

[0059] In one embodiment, performing multiple charging processes on the battery cell includes: performing a static process on the battery cell after each charging process on the battery cell.

[0060] In this embodiment, after the battery cell is charged for the first time, the battery cell is left to stand for the first time; after the battery cell is charged for the second time, the battery cell is left to stand for the second time; after the battery cell is charged for the third time, the battery cell is left to stand for the third time.

[0061] In one embodiment, the first standing treatment lasts 4 to 6 minutes, for example, 4 minutes, 5 minutes or 6 minutes; the second standing treatment lasts 1.6 to 2.4 minutes, for example, 1.6 minutes, 2 minutes or 2.4 minutes; the third standing treatment lasts 4 to 6 minutes, for example, 4 minutes, 5 minutes or 6 minutes.

[0062] In one embodiment, the step of forming a battery cell includes: forming a positive electrode sheet and a negative electrode sheet respectively; placing a separator between the positive electrode sheet and the negative electrode sheet and winding them to form a battery cell.

[0063] In one embodiment, the surface density of the positive electrode sheet is greater than or equal to 350g / 1540.25mm 2The compaction density of the positive electrode is 2.55g / cc; the surface density of the negative electrode is greater than or equal to 170g / 1540.25mm 2 The compaction density of the positive electrode sheet is 1.6g / cc. The above-mentioned infiltration treatment method can improve the infiltration effect of the electrolyte on the battery cell with high surface density and high compaction density; and the above-mentioned charging treatment method can improve the quality of the interface film formed by the reaction between the electrolyte and the electrode material, and avoid the abnormal charging of the battery cell with high surface density and high compaction density.

[0064] In summary, by adopting the battery preparation method provided by the present application, the battery cell is subjected to multiple alternating first and second wetting treatments, and the number, temperature and duration of the first and second wetting treatments are selected within the above-mentioned ranges; and in combination with selecting the number of charging treatments for the battery cell, the environmental negative pressure value and the rate during the charging treatment within the above-mentioned ranges, it is possible to better take into account the requirements of good wetting effect of the electrolyte on high surface density and high compaction density battery cells, high stability, high density and thickness consistency of the interface film formed by the reaction of the electrode material and the electrolyte, and low production cost, thereby avoiding charging abnormalities of high surface density and high compaction density battery cells and improving the reliability of the battery.

[0065] Another embodiment of the present invention provides a battery, which is prepared by the method for preparing the battery in the above embodiment of the present invention.

[0066] In one embodiment, the battery comprises a lithium battery. In other embodiments, the battery comprises a battery of other materials.

[0067] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a battery, characterized in that: include: forming a battery cell; Performing an infiltration treatment on the battery cell; The soaking treatment of the battery cell comprises: performing a plurality of alternating first soaking treatments and second soaking treatments on the battery cell; wherein the temperature of the first soaking treatment is greater than the temperature of the second soaking treatment; The battery cell is subjected to multiple charging treatments; during the multiple charging treatments, the environmental negative pressure value of the subsequent charging treatment is less than or equal to the environmental negative pressure value of the previous charging treatment.

2. The method for preparing a battery according to claim 1, characterized in that: The infiltration treatment of the battery cell includes: performing the first infiltration treatment on the battery cell N times; performing the second infiltration treatment on the battery cell N-1 times; N is an integer greater than or equal to 2.

3. The method for preparing a battery according to claim 1 or 2, characterized in that: The temperature of the first immersion treatment is 40°C to 50°C; the temperature of the second immersion treatment is 15°C to 25°C.

4. The method for preparing a battery according to claim 1, characterized in that: The number of times the charging process is performed on the battery cell is greater than or equal to 3 times.

5. The method for preparing a battery according to claim 1, characterized in that: The charging process of the battery cell is performed multiple times, including: performing a first charging process, a second charging process and a third charging process on the battery cell in sequence; The environmental negative pressure value of the second charging process is equal to the environmental negative pressure value of the first charging process, and the environmental negative pressure value of the third charging process is less than the environmental negative pressure value of the second charging process.

6. The method for preparing a battery according to claim 5, characterized in that: Also includes: Performing a fourth charging process on the battery cell; Wherein, the environmental negative pressure value of the fourth charging process is less than or equal to the environmental negative pressure value of the third charging process.

7. The method for preparing a battery according to claim 6, characterized in that: The environmental negative pressure value of the first charging treatment is -35Kpa~-45Kpa; the environmental negative pressure value of the second charging treatment is -35Kpa~-45Kpa; the environmental negative pressure value of the third charging treatment is -70Kpa~-80Kpa; the environmental negative pressure value of the fourth charging treatment is -70Kpa~-80Kpa.

8. The method for preparing a battery according to claim 1, characterized in that: During multiple charging processes, the rate of the subsequent charging process is greater than or equal to the rate of the previous charging process; When the battery cell is subjected to the charging treatment multiple times, including: sequentially performing a first charging treatment, a second charging treatment, a third charging treatment and a fourth charging treatment on the battery cell, the ratio of the first charging treatment is 0.01C to 0.02C, the ratio of the second charging treatment is less than or equal to 0.025C, the ratio of the third charging treatment is less than or equal to 0.1C, and the ratio of the fourth charging treatment is less than or equal to 0.15C.

9. The method for preparing a battery according to claim 1, characterized in that: Also includes: After the battery cell is subjected to the wetting treatment and before the battery cell is subjected to the charging treatment multiple times, the battery cell is subjected to the static treatment; The temperature of the static treatment is 15° C. to 25° C., and the duration is 4 h to 6 h.

10. A battery, characterized in that: The battery is prepared by the method for preparing the battery according to any one of claims 1 to 9.

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