阅读说明：本技术 一种锂离子电池的注液方法 (Liquid injection method of lithium ion battery ) 是由 孙学初 艾思伟 徐悦斌 刘金成 刘建华 于 2020-12-31 设计创作，主要内容包括：本发明涉及锂离子电池技术领域,公开了一种锂离子电池的注液方法,包括：S1：对电池壳体内部抽真空至真空度为-90kpa～-95kpa并保持第一预设时间,S2：向电池壳体内注入电解液,S3：对电池壳体内部加压至电池壳体内达到预设压力并保持第二预设时间,以使电池壳体膨胀产生弹性形变,S4：对电池壳体泄压,S5：对电池壳体内部依次进行抽真空、破真空、加压及泄压,并重复至少两次,S6：对电池壳体内部加压以使电池壳体内压力至450kpa～550kpa并保持第三预设时间,S7：对电池壳体泄压,完成注液。通过使电池壳体膨胀产生弹性形变,能够增大电池壳体内壁与卷芯之间的间隙,加快电解液浸润卷芯,提高注液效率。(The invention relates to the technical field of lithium ion batteries, and discloses a liquid injection method of a lithium ion battery, which comprises the following steps: s1: vacuumizing the interior of the battery shell until the vacuum degree is-90 to-95 kpa, and keeping for a first preset time, S2: injecting an electrolyte into the battery case, S3: pressurizing the inside of the battery shell to reach a preset pressure in the battery shell and keeping the pressure for a second preset time so that the battery shell expands to generate elastic deformation, S4: pressure relief to the battery case, S5: and (2) sequentially vacuumizing, breaking vacuum, pressurizing and relieving pressure in the battery shell, and repeating at least twice, wherein the step (S6): pressurizing the inside of the battery case to make the pressure in the battery case reach 450 kpa-550 kpa and keeping for a third preset time, S7: and (5) releasing the pressure of the battery shell to finish liquid injection. Elastic deformation is generated by expansion of the battery shell, so that the gap between the inner wall of the battery shell and the roll core can be increased, the roll core is soaked by electrolyte, and the liquid injection efficiency is improved.)

1. The liquid injection method of the lithium ion battery is characterized by comprising the following steps:

s1: vacuumizing the interior of the battery shell (1) until the vacuum degree is-90 to-95 kpa, and keeping for a first preset time;

s2: injecting an electrolyte into the battery case (1);

s3: pressurizing the interior of the battery shell (1) into the battery shell (1) to reach a preset pressure and keeping for a second preset time so as to enable the battery shell (1) to expand to generate elastic deformation;

s4: -relieving the battery housing (1);

s5: sequentially vacuumizing, breaking vacuum, pressurizing and decompressing the interior of the battery shell (1), and repeating at least twice;

s6: pressurizing the interior of the battery shell (1) to enable the pressure in the battery shell (1) to be 450-550 kpa and keeping the pressure for a third preset time;

s7: and (3) releasing the pressure of the battery shell (1) to finish liquid injection.

2. The electrolyte injection method for the lithium ion battery according to claim 1, wherein the material of the battery case (1) is aluminum, and in S3, the sum of the time for the pressure in the battery case (1) to reach the preset pressure and the second preset time is 200S, and the preset pressure is 1000kpa to 1100 kpa.

3. The electrolyte injection method for a lithium ion battery according to claim 1, wherein in S5, the evacuation is to evacuate the interior of the battery case (1) to a vacuum degree of-90 kpa to-95 kpa for a fourth preset time, and the pressurization is to pressurize the interior of the battery case (1) to make the pressure in the battery case (1) to 450kpa to 550kpa for a fifth preset time, and the preset pressure is greater than 550 kpa.

4. The electrolyte injection method for a lithium ion battery according to claim 1, wherein in S5, the evacuation time is 150S, the vacuum breaking time is 100S, the pressurization time is 200S, and the pressure relief time is 100S.

5. The electrolyte injection method for a lithium ion battery according to claim 1, wherein the sum of the time for which the pressure in the battery case (1) reaches-90 kpa to-95 kpa and the first preset time is 155S at S1.

6. The method for injecting a lithium ion battery according to claim 1, wherein a time period during which the air is introduced into the battery case (1) at S4 is 100S.

7. The electrolyte injection method for a lithium ion battery according to claim 1, wherein in S6, the sum of the time for which the pressure in the battery case (1) reaches 450kpa to 550kpa and the third preset time is 200S.

8. The method for injecting a lithium ion battery according to claim 1, wherein a time period during which the air is introduced into the battery case (1) at S7 is 100S.

9. The electrolyte injection method of the lithium ion battery according to claim 1, further comprising: placing the battery shell (1) in a battery clamp (2) before S1, wherein the battery clamp (2) is provided with a first inner cavity (21) for accommodating the battery shell (1), and a gap is reserved between at least part of the outer peripheral surface of the battery shell (1) and the inner wall of the battery clamp (2) corresponding to the first inner cavity (21).

10. The electrolyte injection method of the lithium ion battery according to claim 9, wherein the battery holder (2) further has a second inner cavity and a third inner cavity which are located at the upper and lower sides of the first inner cavity (21) and are respectively communicated with the first inner cavity (21), and the outer peripheral surface of the battery case (1) abuts against the inner walls of the battery holder (2) corresponding to the second inner cavity and the third inner cavity.

Technical Field

The invention relates to the technical field of lithium ion batteries, in particular to a liquid injection method of a lithium ion battery.

Background

The lithium ion battery generally comprises a battery shell, and an electric core and electrolyte accommodated in the battery shell, wherein the electric core comprises a positive electrode, a negative electrode and a diaphragm positioned between the positive electrode and the negative electrode, the electrolyte plays a role in conducting between the positive electrode and the negative electrode of the lithium ion battery, and is used as a lithium ion current transmission medium in the charging and discharging processes of the battery, so that the lithium ion battery can obtain the advantages of high voltage, high specific energy and the like.

Therefore, in the production process of the lithium ion battery, electrolyte injection is very important process operation, after the battery is assembled, electrolyte is injected into the battery, and the battery after the electrolyte injection is kept still, so that the electrolyte can fully infiltrate the positive electrode, the negative electrode and the diaphragm of the battery. However, due to the demand of high energy density and high capacity of the lithium ion battery, the winding of the battery core is tighter and tighter, the chemical substances in the battery core are increased, the space is reduced, and the electrolyte permeation is slower by adopting a common electrolyte injection method, so that the electrolyte injection time is longer.

Therefore, a liquid injection method for a lithium ion battery is needed to improve the liquid injection efficiency of the lithium ion battery.

Disclosure of Invention

The invention aims to provide a liquid injection method of a lithium ion battery, which aims to improve the liquid injection efficiency of the lithium ion battery.

As the conception, the technical scheme adopted by the invention is as follows:

a liquid injection method of a lithium ion battery comprises the following steps:

s1: vacuumizing the interior of the battery shell until the vacuum degree is-90 to-95 kpa, and keeping for a first preset time;

s2: injecting electrolyte into the battery shell;

s3: pressurizing the interior of the battery shell to a preset pressure in the battery shell and keeping the pressure for a second preset time so as to enable the battery shell to expand to generate elastic deformation;

s4: releasing pressure to the battery shell;

s5: sequentially vacuumizing, breaking vacuum, pressurizing and decompressing the interior of the battery shell, and repeating at least twice;

s6: pressurizing the interior of the battery shell to enable the pressure in the battery shell to be 450-550 kpa and keeping the pressure for a third preset time;

s7: and (5) releasing the pressure of the battery shell to finish liquid injection.

Further, the material of the battery case is aluminum, in S3, the sum of the time when the pressure in the battery case reaches the preset pressure and the second preset time is 200S, and the preset pressure is 1000kpa to 1100 kpa.

Further, in S5, the evacuating is to evacuate the interior of the battery case to a vacuum degree of-90 kpa to-95 kpa for a fourth preset time, and the pressurizing is to pressurize the interior of the battery case to a pressure in the battery case of 450kpa to 550kpa for a fifth preset time, where the preset pressure is greater than 550 kpa.

Further, in S5, the time for evacuation is 150S, the time for breaking vacuum is 100S, the time for pressurizing is 200S, and the time for depressurizing is 100S.

Further, in S1, the sum of the time for which the pressure in the battery case reaches-90 kpa to-95 kpa and the first preset time is 155S.

Further, in S4, the time period during which the atmosphere is introduced into the battery case is 100S.

Further, in S6, the sum of the time for which the pressure in the battery case reaches 450kpa to 550kpa and the third preset time is 200S.

Further, in S7, the time period during which the atmosphere is introduced into the battery case is 100S.

Further, the method for injecting the lithium ion battery further includes, before S1, placing the battery case in a battery clamp, where the battery clamp has a first inner cavity for accommodating the battery case, and a gap is formed between at least a part of an outer peripheral surface of the battery case and an inner wall of the battery clamp corresponding to the first inner cavity.

Furthermore, the battery clamp is further provided with a second inner cavity and a third inner cavity which are positioned on the upper side and the lower side of the first inner cavity and are respectively communicated with the first inner cavity, and the peripheral surface of the battery shell is abutted against the inner walls of the battery clamp corresponding to the second inner cavity and the third inner cavity.

The invention has the beneficial effects that:

the liquid injection method of the lithium ion battery comprises the steps of sequentially vacuumizing the interior of a battery shell in S1 until the vacuum degree is-90 kpa-95 kpa and keeping the vacuum degree for a first preset time; injecting an electrolyte into the battery case in S2; pressurizing the interior of the battery shell to a preset pressure in the battery shell and keeping the pressure for a second preset time in S3 so that the battery shell expands to generate elastic deformation; venting the battery case in S4; in S5, sequentially vacuumizing, breaking vacuum, pressurizing and decompressing the interior of the battery shell, and repeating at least twice; pressurizing the inside of the battery case at S6 to bring the pressure inside the battery case to 450kpa to 550kpa and maintaining for a third preset time; in S7, the battery case is depressurized to complete the liquid injection. Under this setting, in S3, because the battery shell inflation, and make the clearance increase between the inner wall of battery shell and the book core, can effectively promote the rate that the book core was soaked to electrolyte, improve and annotate liquid efficiency to shorten battery production cycle, reduce production manufacturing cost.

Drawings

Fig. 1 is a flowchart of a liquid injection method for a lithium ion battery according to an embodiment of the present invention;

fig. 2 is a schematic assembly diagram of a lithium ion battery and a battery clamp according to an embodiment of the present invention.

In the figure:

1. a battery case;

2. a battery clamp; 21. a first lumen.

Detailed Description

In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are used based on the orientations and positional relationships shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be configured and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

As shown in fig. 1, the present embodiment provides a liquid injection method for a lithium ion battery, including the following steps: s1: vacuumizing the interior of the battery shell 1 until the vacuum degree is-90 kpa to-95 kpa, and keeping for a first preset time; s2: injecting an electrolyte into the battery case 1; s3: pressurizing the interior of the battery shell 1 until the interior of the battery shell 1 reaches a preset pressure and keeping for a second preset time so as to enable the battery shell 1 to expand to generate elastic deformation; s4: releasing the pressure of the battery shell 1; s5: sequentially vacuumizing, breaking vacuum, pressurizing and decompressing the interior of the battery shell 1, and repeating at least twice; s6: pressurizing the interior of the battery shell 1 to ensure that the pressure in the battery shell 1 reaches 450-550 kpa and keeps for a third preset time; s7: and (5) releasing the pressure of the battery shell 1 to finish liquid injection. Specifically, the inside of the battery case 1 is evacuated in S1 at a degree of vacuum that may be-90 kpa, -91kpa, -92kpa, -93kpa, -94kpa, -95kpa, etc., whereas in the present embodiment, the inside of the battery case 1 is preferably evacuated to a degree of vacuum of-95 kpa. Similarly, the inside of the battery case 1 is pressurized at S6 at a pressure value of 450kpa, 480kpa, 510kpa, 550kpa, etc., whereas in the present embodiment, it is preferable to pressurize the inside of the battery case 1 so that the pressure in the battery case 1 becomes 500 kpa.

The inside of the battery case 1 can be maintained at a high vacuum through S1, and then the electrolyte can be injected into the inside of the battery case 1 more easily by using the pressure difference between the inside and the outside of the battery case 1, and after the electrolyte already exists in the inside of the battery case 1, it is most important to make the electrolyte in the inside of the battery case 1 fully infiltrate into the battery cell. The battery after being injected with the electrolyte is generally kept still to complete the soaking, specifically, the battery can be kept still for a long time to ensure that the electrolyte can fully soak the battery core, but the battery can absorb a large amount of moisture and impurities after being exposed to the air for a long time, so that the safety and the electrochemical performance of the battery are affected. Therefore, in this embodiment, through letting in high malleation to battery case 1 inside to make battery case 1 inflation produce elastic deformation, thereby increase the clearance between 1 inner wall of battery case and the book core, this difficulty that not only can reduce to the inside injection electrolyte of battery case 1, can also shorten the time that the electric core was soaked to electrolyte, thereby effectively improve notes liquid efficiency.

In S1, the sum of the time taken for the pressure in the battery case 1 to reach-90 kpa to-95 kpa and the first predetermined time is 155S. That is, the vacuum value should not be too high, and the time for maintaining the vacuum should not be too long, so as to prevent the battery case 1 from being deformed toward the inner direction thereof, that is, the inner volume of the battery case 1 from being reduced, and the electrolyte injection process from being difficult.

In this example, the battery case 1 is made of aluminum, and the aluminum case is used to replace the conventional steel case, so that the overall weight of the battery can be reduced, and the energy density of the lithium ion battery can be improved. Specifically, in S3, the pressure inside the battery case 1 should be set to 1000kpa to 1100kpa until the preset pressure inside the battery case 1 is reached, and the sum of the time required for the pressure inside the battery case 1 to reach the preset pressure and the time for the pressure inside the battery case 1 to be maintained at the preset pressure should be 200S. Specifically, in the present embodiment, the preset pressure is preferably 1050 kpa. In addition, the time for which the pressure in the battery case 1 is maintained at 1050kpa, that is, the value of the second preset time, is variable because of errors that may exist during the operation, and differences in the pressurizing devices. If the time required for the pressure in the battery case 1 to reach 1050kpa is long, the time required for the pressure to be maintained in the battery case 1 to reach 1050kpa is correspondingly shortened, whereas if the time required for the pressure in the battery case 1 to reach 1050kpa is short, the time required for the pressure to be maintained in the battery case 1 to reach 1050kpa is correspondingly lengthened, that is, the sum of the two is ensured to be 200S.

Alternatively, in the present embodiment, the inside of the battery case 1 is pressurized by filling nitrogen gas with a pressure of 200kpa into the inside of the battery case 1 to pressurize the inside until the pressure inside the battery case 1 reaches 1050kpa, and then entering the pressure holding stage. Of course, in another embodiment, the above-mentioned pressurization of the inside of the battery case 1 may be achieved by filling inert gases with different pressures into the battery case 1 or directly introducing the atmosphere.

Further, in S5, the evacuation is performed to evacuate the interior of the battery case 1 to a degree of vacuum of-90 kpa to-95 kpa for a fourth preset time, and the pressurization is performed to pressurize the interior of the battery case 1 to a pressure of 450kpa to 550kpa for a fifth preset time. By performing the above operations of vacuum pumping, vacuum breaking, pressurization and pressure relief on the battery case 1, the sufficient infiltration of the electrolyte to the battery core can be further promoted. Specifically, in this embodiment, the time for vacuumizing is 150S, the time for breaking vacuum is 100S, the time for pressurizing is 200S, and the time for releasing pressure is 100S, where it should be noted that the time for vacuumizing is 150S, specifically, the sum of the time required for vacuumizing the interior of the battery case 1 to a vacuum degree of-90 kpa to-95 kpa and a fourth preset time is 150S, where the fourth preset time may change to some extent due to different vacuumizing apparatuses and other reasons. The pressurization time is 200S, which specifically means that the sum of the time required for pressurizing the interior of the battery case 1 so as to make the pressure in the battery case 1 reach 450kpa to 550kpa and a fifth preset time is 200S, wherein the fifth preset time may be changed to some extent due to different pressurization devices and the like. In S5 of the present embodiment, the inside of the battery case 1 is preferably evacuated to a vacuum degree of-95 kpa, and the inside of the battery case 1 is preferably pressurized to a pressure of 500 kpa.

Specifically, in this embodiment, the operations of vacuum pumping, vacuum breaking, pressurizing and pressure releasing are repeated twice to ensure that the electrolyte can fully infiltrate the battery cell during the cyclic alternation of vacuum pumping and pressurizing. Of course, in other embodiments, the number of repetitions of S5 is determined according to the shape and size of the battery, and in practical applications, the specific number of repetitions may be determined through experiments.

Further, in S6, the sum of the time for the pressure in the battery case 1 to reach 450kpa to 550kpa and the third preset time is 200S, that is, in this embodiment S6, the sum of the time for the pressure in the battery case 1 to reach 500kpa and the third preset time is 200S. Then, in S7, the battery case 1 is depressurized to complete the liquid injection.

In this embodiment, the breaking of vacuum and the pressure relief in the above steps can be realized by introducing air into the battery case 1. Specifically, in S4, the time period during which the atmosphere is allowed to flow into the battery case 1 is 100S. At S7, the time period during which the air is introduced into the battery case 1 is 100S. In addition, in other embodiments, the vacuum breaking and the pressure relief may also be implemented by using other devices or methods according to actual conditions, which are not described herein again.

As shown in fig. 2, the liquid injection method for a lithium ion battery provided in this embodiment further includes: before S1, the battery case 1 is placed in the battery holder 2, the battery holder 2 has a first inner cavity 21 for accommodating the battery case 1, and a gap is provided between at least a part of the outer peripheral surface of the battery case 1 and the inner wall of the battery holder 2 corresponding to the first inner cavity 21. In the present embodiment, the battery is preferably a cylindrical battery, and the first inner cavity 21 of the battery holder 2 is preferably a cylindrical battery, and at this time, in the radial direction of the cylindrical battery, a preset gap is provided between the inner wall of the battery holder 2 corresponding to the first inner cavity 21 and the outer circumferential surface of the battery case 1. Specifically, the preset gap is present to limit the extent of deformation of the battery case 1, i.e., to further ensure that the battery case 1 changes to elastic deformation, which can be recovered by standing.

Further, battery anchor clamps 2 still has the second inner chamber and the third inner chamber that are located first inner chamber 21 upper and lower both sides and all communicate respectively with first inner chamber 21, and the outer peripheral face butt of battery shell 1 is in battery anchor clamps 2 and the inner wall that second inner chamber and third inner chamber correspond. With cylinder battery assorted, the second inner chamber and the third inner chamber of battery anchor clamps 2 all set up to cylindrically, place in this battery anchor clamps 2 when the battery, the both ends on its axial direction all can be fixed by battery anchor clamps 2, and further, this battery anchor clamps 2 can also inject the region that battery case 1 takes place deformation, and battery case 1's deformation only appears on the outer peripheral face of battery case 1 that corresponds with first inner chamber 21 promptly. In addition, when the battery case 1 is disposed in the battery clamp 2, one end of the battery case 1 in the axial direction can extend out of the battery clamp 2, which not only can ensure the fixing effect of the battery clamp 2 on the battery case 1, but also can facilitate the putting in and taking out of the battery case 1. Alternatively, the battery holder 2 is integrally formed or has a separate structure.

Of course, in other embodiments, the battery may have a square structure, in which case the battery case 1 expands in four plane portions in the circumferential direction thereof to be elastically deformed. At this time, the battery clamp 2 corresponding to the square battery is slightly different from the battery clamp 2 corresponding to the cylindrical battery, specifically, when the square battery is placed in the battery clamp 2, except for the outer peripheral surface of the battery case 1 abutting against the inner walls of the battery clamp 2 corresponding to the second inner cavity and the third inner cavity, four corners of the battery case 1 in the circumferential direction abut against the inner walls of the battery clamp 2 corresponding to the first inner cavity 21, so as to limit the four corners from being deformed.

Preferably, in this embodiment, the second inner cavity and the third inner cavity of the battery holder 2 are rectangular, and the first inner cavity 21 is configured as a cylinder or an elliptic cylinder, it can be understood that if the cross section of the battery housing 1 is square in the horizontal direction, the cross section of the first inner cavity 21 is circular, and the size of the cross section of the first inner cavity 21 is equal to the size of the circumscribed circle of the cross section of the battery housing 1, so as to ensure that four corners of the battery housing 1 in the circumferential direction thereof are abutted to the inner wall of the battery holder 2 corresponding to the first inner cavity 21, and in addition, if the cross section of the battery housing 1 is rectangular in the horizontal direction, the cross section of the first inner cavity 21 is elliptical. In another embodiment, when the battery is of a square structure, the first inner cavity 21 may also be set to have another shape, that is, it is only necessary to ensure that four corners of the square battery in the circumferential direction can abut against the inner wall of the battery clamp 2 corresponding to the first inner cavity 21, and details are not repeated.

Finally, it should be noted that, compared with the existing electrolyte injection method, the electrolyte injection method of the lithium ion battery provided in this embodiment can effectively improve the electrolyte injection efficiency, and specifically, the electrolyte injection time of the lithium ion battery can be shortened by 15%.

The foregoing embodiments are merely illustrative of the principles and features of this invention, which is not limited to the above-described embodiments, but rather is susceptible to various changes and modifications without departing from the spirit and scope of the invention, which changes and modifications are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.