阅读说明：本技术 一种解决方形铝壳电池壳体凹陷的注液方法 (Liquid injection method for solving problem of sinking of square aluminum shell battery shell ) 是由 房子魁 姚汪兵 于 2020-12-15 设计创作，主要内容包括：本发明公开了一种解决方形铝壳电池壳体凹陷的注液方法,涉及锂离子电池生产技术领域,包括以下步骤：将方形铝壳的锂离子电池固定在电池托盘上,同时将装有电解液的电解液杯固定在锂离子电池注液孔上方,然后将电池托盘置于真空罩内,开始注液；对真空罩进行抽真空,保压；对真空罩进行阶梯式充正压,是向真空罩内分多次充入氮气,每次冲入氮气后保压；对真空罩进行泄压至常压状态；根据注入电解液的量重复上述抽真空-阶梯式充正压-泄压操作,注液完成。本发明通过对放置有锂离子电池的真空罩先抽真空、然后阶梯式充正压再泄压操作,不仅能解决电池铝壳凹陷的外观问题,而且能改善电解液吸收效果,减少注液时间,提高注液效率。(The invention discloses a liquid injection method for solving the problem of the sinking of a square aluminum shell battery shell, which relates to the technical field of lithium ion battery production and comprises the following steps: fixing a lithium ion battery with a square aluminum shell on a battery tray, fixing an electrolyte cup filled with electrolyte above an electrolyte injection hole of the lithium ion battery, and then placing the battery tray in a vacuum cover to start electrolyte injection; vacuumizing the vacuum cover and maintaining the pressure; filling nitrogen into the vacuum cover for multiple times, and maintaining the pressure after filling the nitrogen each time; releasing the pressure of the vacuum cover to a normal pressure state; and repeating the operations of vacuumizing, stepped positive pressure charging and pressure releasing according to the amount of the injected electrolyte, and finishing the injection. According to the invention, the vacuum cover provided with the lithium ion battery is firstly vacuumized, and then is subjected to step-type positive pressure charging and pressure releasing operation, so that the appearance problem of the concave aluminum shell of the battery can be solved, the electrolyte absorption effect can be improved, the electrolyte injection time is shortened, and the electrolyte injection efficiency is improved.)

1. A liquid injection method for solving the problem of the sinking of a square aluminum shell battery shell is characterized by comprising the following steps:

s1, fixing the lithium ion battery with a square aluminum shell on a battery tray, fixing an electrolyte cup filled with electrolyte above a lithium ion battery electrolyte injection hole, and then placing the battery tray in a vacuum cover to start electrolyte injection;

s2, vacuumizing the vacuum cover, and maintaining the pressure;

s3, performing step positive pressure filling on the vacuum cover, namely filling nitrogen into the vacuum cover for multiple times, and maintaining the pressure after filling the nitrogen each time;

s4, decompressing the vacuum cover to a normal pressure state;

and S5, repeating the steps S2-S4 according to the amount of the injected electrolyte, and finishing the injection.

2. The electrolyte injection method for solving the problem of the dent of the square aluminum-shell battery shell according to claim 1, wherein in S2, the vacuum degree is pumped to-85 to-95 kPa, and the pressure maintaining time is 30 to 60S.

3. The electrolyte injection method for solving the problem of the dent of the square aluminum-shell battery shell according to claim 1, wherein in S3, nitrogen is injected into the vacuum cover for three times, the first nitrogen injection time is 0.5-1S, and the pressure maintaining time is 30-40S; the nitrogen is filled for the second time for 1.5 to 2 seconds, and the pressure maintaining time is 20 to 30 seconds; and the nitrogen is filled for 2-3 s for the third time, the air pressure is not less than 600kPa, and the pressure maintaining time is 500-600 s.

4. The electrolyte injection method for solving the problem of the dent in the square aluminum-shell battery case as claimed in claim 1, wherein in S5, the steps S2-S4 are repeated 1-3 times according to the amount of the injected electrolyte.

Technical Field

The invention relates to the technical field of lithium ion battery production, in particular to a liquid injection method for solving the problem of depression of a square aluminum shell battery shell.

Background

With the exhaustion of traditional energy and the increasingly prominent problem of climate warming, people need a new green energy to replace the traditional energy. The development direction of lithium ion batteries as novel clean energy is increasingly emphasized by governments and scientists, and the development and research of lithium ion batteries with more practical and efficient performance are continuously dedicated. Compared with the traditional lead storage battery and nickel metal hydride battery, the lithium ion battery has obvious advantages in cycle life, energy density, power density and environment-friendly performance. Although there is a gap in energy density from the fuel cell, the high manufacturing cost and the complicated production process of the fuel cell make it difficult to commercialize it. Therefore, the lithium ion battery is an ideal power source for future electric vehicles and hybrid batteries.

The electrolyte injection process is an essential and important process in the production process of the lithium ion battery. At present, most companies adopt an isobaric liquid injection mode, a battery is placed in an independent vacuum cover, and the absorption of electrolyte is accelerated through a standing mode of alternately circulating high pressure and vacuum. Although the battery is in the vacuum cover, the internal and external pressure of battery case is balanced, guarantees that the battery can not bulge, in fact, after the evacuation, when pouring nitrogen into fast in the vacuum cover, because nitrogen fills the space in the vacuum cover earlier, so atmospheric pressure in the vacuum cover will be greater than the inside atmospheric pressure of battery to "crowded" deformation with the aluminum hull battery leads to the casing inwards sunken, causes the battery outward appearance bad.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides a liquid injection method for solving the problem of the sinking of a square aluminum shell battery shell, which not only can solve the problem of the appearance of the sinking of the battery aluminum shell in the liquid injection process, but also can improve the absorption effect of electrolyte.

The invention provides a liquid injection method for solving the problem of the sinking of a square aluminum shell battery shell, which comprises the following steps of:

s1, fixing the lithium ion battery with a square aluminum shell on a battery tray, fixing an electrolyte cup filled with electrolyte above a lithium ion battery electrolyte injection hole, and then placing the battery tray in a vacuum cover to start electrolyte injection;

s2, vacuumizing the vacuum cover, and maintaining the pressure;

s3, performing step positive pressure filling on the vacuum cover, namely filling nitrogen into the vacuum cover for multiple times, and maintaining the pressure after filling the nitrogen each time;

s4, decompressing the vacuum cover to a normal pressure state;

and S5, repeating the steps S2-S4 according to the amount of the injected electrolyte, and finishing the injection.

Preferably, in S2, the vacuum degree is pumped to-85 to-95 kPa, and the pressure maintaining time is 30 to 60S.

Preferably, in S3, nitrogen is filled into the vacuum cover for three times, the first nitrogen filling time is 0.5-1S, and the pressure maintaining time is 30-40S; the nitrogen is filled for the second time for 1.5 to 2 seconds, and the pressure maintaining time is 20 to 30 seconds; and the nitrogen is filled for 2-3 s for the third time, the air pressure is not less than 600kPa, and the pressure maintaining time is 500-600 s.

Preferably, in S5, repeating the steps S2-S4 1-3 times according to the amount of the injected electrolyte.

Has the advantages that: the vacuum cover provided with the lithium ion battery is firstly vacuumized, then is subjected to step-type positive pressure charging and then pressure relief operation, so that no pressure difference exists between the interior of the battery shell and the interior of the standing cover, and the battery shell is not extruded. Therefore, the invention solves the appearance problem of the battery aluminum shell recess by adopting the liquid injection method of step positive pressure charging, and can improve the electrolyte absorption effect, reduce the liquid injection time and improve the liquid injection efficiency. The invention has unique thought, strong practicability and wide application range.

Drawings

FIG. 1 is a schematic side view of a battery according to example 1 of the present invention after liquid injection; wherein, a is a test group, and b is a control group;

FIG. 2 is a physical diagram of the appearance of a battery after charging in example 1 of the present invention; wherein, a is a test group, and b is a control group.

Detailed Description

The technical solution of the present invention will be described in detail below with reference to specific examples.

Example 1

Selecting a square aluminum shell lithium ion battery for liquid injection, and comprising the following steps:

(1) fixing a lithium ion battery with a square aluminum shell on a battery tray, fixing an electrolyte cup filled with electrolyte above an electrolyte injection hole of the lithium ion battery, and then placing the battery tray in a vacuum cover to start electrolyte injection;

(2) firstly, vacuumizing a vacuum cover, and keeping the pressure for 30s after the negative pressure reaches-90 kPa;

(3) step positive pressure charging: filling nitrogen for 1s for the first time, and maintaining the pressure for 30 s; filling nitrogen for 2s for the second time, maintaining the pressure for 20s, filling nitrogen for 3s for the third time, and maintaining the pressure for 500s when the air pressure reaches 650 kPa;

(4) the vacuum cover is decompressed and is restored to the normal pressure state;

(5) repeating the steps (2) to (4) for 1 time.

By adopting the stepped positive pressure charging method, the battery after liquid charging is recorded as a test group; the method adopts the isobaric injection method (the isobaric injection method is that after the vacuum cover is vacuumized, nitrogen is filled into the vacuum cover once to ensure that the pressure reaches 650kPa instantly, other test parameters are the same as those of a test group), and the battery after liquid injection is marked as a control group. The test results are shown in fig. 1-2 and table 1, and as shown in fig. 2, the appearance of the battery before and after the two groups of liquid injection is observed, and it is found that the appearance of the battery after the test group is injected with the liquid is not sunken, no electrolyte emerges, and the battery of the control group is seriously sunken, so that the appearance is poor. In addition, when the same electrolyte amount is injected, the whole injection process of the test group takes 11min, and the injection process of the comparison group takes 23min, so that more than half of time is saved, and the injection efficiency is greatly improved.

TABLE 1 injection time for test group and control group

Group of	Liquid injection method	Amount of liquid injected	Time of injection
				Test group	Stepped positive pressure charge	240g	11min
Control group	Isobaric injection	240g	23min

Example 2

Selecting a square aluminum shell lithium ion battery for liquid injection, and comprising the following steps:

(1) fixing a lithium ion battery with a square aluminum shell on a battery tray, fixing an electrolyte cup filled with electrolyte above an electrolyte injection hole of the lithium ion battery, and then placing the battery tray in a vacuum cover to start electrolyte injection;

(2) firstly, vacuumizing a vacuum cover, and keeping the pressure for 40s after the negative pressure reaches-90 kPa;

(3) step positive pressure charging: filling nitrogen for 0.5s for the first time, and maintaining the pressure for 40 s; filling nitrogen for 1.5s for the second time, maintaining the pressure for 30s, filling nitrogen for 3s for the third time, and maintaining the pressure for 500s when the air pressure reaches 600 kPa;

(4) the vacuum cover is decompressed and is restored to the normal pressure state;

(5) repeating the steps (2) to (4) for 2 times.

By adopting the liquid injection method of the step positive pressure charging, the battery after liquid injection is recorded as a test group, the appearance of the battery has no depression, and no electrolyte emerges. And the battery adopting the isobaric injection method (the isobaric injection method is that after the vacuum cover is vacuumized, nitrogen is filled into the vacuum cover once to ensure that the pressure reaches 600kPa instantly, and other test parameters are the same as those of the test group) is marked as a control group, and the battery is seriously sunken to cause poor appearance. The injection time of the two methods is shown in table 2, when the same amount of electrolyte is injected, the whole injection process of the test group takes 21min, while the injection time of the comparison group takes 23min, so that the injection efficiency is greatly improved by saving 2 min.

TABLE 2 injection time chart of two injection methods

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.