阅读说明：本技术 一种改善软包卷绕电池的极片浸润及侧边变形的包装注液方法 (Packaging liquid injection method for improving pole piece infiltration and side edge deformation of soft package winding battery ) 是由 王恒 占克军 夏小勇 庞佩佩 朱坤庆 计阳 刘露 楚英 张涛 于 2019-10-23 设计创作，主要内容包括：本发明涉及一种改善软包卷绕电池的极片浸润及侧边变形的包装注液方法,所述方法包括在软包卷绕电池的卷芯底部设置注液口,并在注液过程中将软包卷绕电池的卷芯头部竖直向下,其一方面使得注液过程中电解液由卷芯的底部沿着卷芯的极片间隙或极片与隔膜的间隙流动到卷芯的头部,从而有利于卷芯极片的均匀浸润,另一方面,注液过程中,卷芯的头部向下,有利于增大卷芯的环压强度,避免卷芯变形,进而有利于提高软包卷绕电池的循环寿命。(The invention relates to a packaging liquid injection method for improving pole piece infiltration and side edge deformation of a soft package winding battery, which comprises the steps of arranging a liquid injection port at the bottom of a winding core of the soft package winding battery, and vertically enabling the head of the winding core of the soft package winding battery to face downwards in the liquid injection process, wherein on one hand, electrolyte flows to the head of the winding core from the bottom of the winding core along the gap between the pole piece of the winding core or the gap between the pole piece and a diaphragm in the liquid injection process, so that the uniform infiltration of the pole piece of the winding core is facilitated, and on the other hand, the head of the winding core faces downwards in the liquid injection process, so that the annular pressure strength of the winding core is facilitated to be increased.)

1. The utility model provides an improve soft packet of package winding battery's pole piece infiltration and side and warp packing notes liquid method which characterized in that, the method include the soft packet of package winding battery's the bottom of rolling up the core sets up annotates the liquid mouth, and the head of the core of soft packet of winding battery is vertical downwards in the notes liquid in-process.

2. The method of claim 1, wherein the jelly-roll of the pouch-wound battery is top-sealed and side-sealed prior to the initiation of the filling.

3. The method of claim 1 or 2, wherein the bottom of the pouch wound battery is provided with an airbag.

4. The method according to any one of claims 1 to 3, wherein the bottom of the pouch wound battery is bottom sealed after the filling is completed.

5. The method of claim 2 or 4, wherein the side seal and/or the bottom seal each independently employ a soft seal or a hard seal.

6. The method of claim 2 or 4, wherein the side seal and/or the bottom seal each independently employ a single fold or a double fold.

7. The method of any one of claims 1-6, wherein the ratio of the width to the length of the winding core of the pouch wound battery is ≥ 1.

8. The method of any one of claims 1-7, wherein the pouch wound battery is packaged with aluminum plastic film.

9. The method according to any one of claims 1 to 8, characterized in that it comprises the steps of:

(1) carrying out top sealing and side sealing on the winding core, and reserving an air bag at the bottom of the winding core as a liquid injection port;

(2) vertically downwards arranging the head of the winding core, and injecting liquid from a bottom liquid injection port;

(3) and (3) after the liquid injection in the step (2) is finished, performing bottom sealing on the bottom of the roll core to obtain the soft package wound battery.

Technical Field

The invention belongs to the field of battery manufacturing, and relates to a packaging liquid injection method for improving pole piece infiltration and side edge deformation of a soft package winding battery.

Background

Lithium ion batteries have been widely used in the fields of mobile phones, notebook computers, charge pal, electric tools, electric vehicles, etc. because of their advantages of high cell voltage, large specific energy, long cycle life, good safety performance, small self-discharge, etc. To the wider roll core (width ratio length is more than or equal to 1) of soft package winding, the roll core is after annotating the liquid, during the imbibition, because roll core length and width are great, lead to electrolyte to pour into the back into from the side, hardly be absorbed by the intermediate position of pole piece uniformly, influence the infiltration effect of pole piece. Poor electrolyte infiltration can cause the ion transmission path to become far away, and then hinders the shuttle of lithium ion between positive negative pole. The electrochemical reaction of the pole piece which is not well infiltrated by the electrolyte is influenced, the interface impedance of the battery is increased, and the multiplying power, the discharge capacity and the cycle life of the battery are influenced. The wide and thin roll core side is put, because of electric core before not having the degasification yet, electric core diaphragm and pole piece have not bonded the design completely and receive the influence of gravity, lead to electric core to be close to the gasbag and warp the problem.

CN202434586U discloses a soft package battery packaging structure, which consists of a battery shell and an aluminum-plastic film, wherein the aluminum-plastic film is divided into an upper layer and a lower layer, an opening is left on one side, and the battery shell is fixed between the upper layer and the lower layer of the aluminum-plastic film and keeps a distance from each edge of the aluminum-plastic film; this scheme laminate polymer battery's notes liquid mouth sets up in the side of rolling up the core, and it annotates the liquid process and has had the problem that roll up the moist inhomogeneous and pole piece deformation of core pole piece to influence laminate polymer battery's performance.

Therefore, the development of the method for packaging and injecting the soft package winding battery, which can improve the infiltration effect of the winding core pole piece and simultaneously avoid the side edge deformation of the winding core, is still significant.

Disclosure of Invention

The invention aims to provide a packaging and liquid injection method for improving pole piece infiltration and side edge deformation of a soft package winding battery, the method is characterized in that a liquid injection port is formed in the bottom of the soft package winding battery, and the head of the soft package winding battery is vertically downward in the liquid injection process, so that electrolyte flows from the bottom of a winding core to the head of the winding core along the gap between the pole piece of the winding core or the gap between the pole piece and a diaphragm in the liquid injection process, and therefore uniform infiltration of the pole piece of the winding core is facilitated.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a packaging liquid injection method for improving pole piece infiltration and side edge deformation of a soft package winding battery.

The in-process of liquid is annotated to traditional laminate polymer winding battery's packing generally adopts earlier to carry out the end seal and the top seal at the core, reserve the air-bag as annotating the liquid mouth at the side of rolling up the core, it annotates the liquid in-process, electrolyte is after getting into the battery inside by the side, the side of rolling up the core is that the one deck is wrapped, electrolyte can reach from the tail two and roll up a core other side bottom, reuse vacuum adsorption, let the middle part of long roll core or the wide pole piece of rolling up the core be close to the air-bag position and absorb electrolyte, and the middle part of long roll core or the wide core of rolling up be close to the air-bag position because the route is far away, hardly like the head and the. Simultaneously, because at the notes liquid in-process, wide and thin book core side is put, because of roll core before still not having the degasification, roll up core diaphragm and pole piece and not bond the design completely and receive the influence of gravity, lead to rolling up the core and be close to the air bag deformation problem.

According to the liquid injection method for packaging the soft package wound battery, the gap between the pole pieces of the winding core and the gap between the pole pieces and the diaphragm are used as the channels in the liquid injection process, so that electrolyte in the liquid injection process reaches the head of the winding core from the bottom of the winding core along the gap between the pole pieces, a better infiltration effect is achieved, the problems that the winding core pole pieces are not well infiltrated and the winding core pole pieces deform close to the side of the airbag belt due to the adoption of side-edge liquid injection in the packaging liquid injection process of the traditional soft package wound battery are solved, and the cycle life of the packaged soft package wound battery is prolonged.

The two ends of the central line of the winding core of the soft package winding battery respectively correspond to the bottom and the head of the winding core, the head of the winding core of the soft package winding battery refers to the position where a pole lug is located, corresponds to a top sealing position, and the end far away from the pole lug is the bottom and corresponds to a bottom sealing; and the other two sides are side edges for side sealing.

Preferably, before the liquid injection is started, the winding core of the soft package winding battery is subjected to top sealing and side sealing.

Preferably, the bottom of the soft-packaged winding battery is provided with an air bag.

Preferably, after the liquid injection is finished, the bottom of the soft-package wound battery is sealed.

The side edge and the bottom of the soft package winding battery are respectively provided with the seal, so that the strength of the aluminum plastic film at the bottom of the winding core for protecting the winding core is enhanced, and the safety performance of falling of the winding core and the like is improved.

Preferably, the side seal and/or the bottom seal are soft seal or hard seal respectively and independently.

Preferably, the side seal and/or the bottom seal are respectively and independently provided with a single folded edge or a double folded edge.

Preferably, the ratio of the width to the length of the winding core of the soft-package winding battery is more than or equal to 1, such as 2, 3, 4, 5, 8 or 10.

The shape of the winding core of the invention is cylindrical, for example, cylindrical, where the width of the winding core refers to the diameter of the outermost ring wound by the winding core, and the length of the winding core refers to the distance from the head of the winding core to the bottom (excluding the length occupied by the tabs), i.e., the width of the separator used.

Preferably, the soft-packaged winding battery is packaged by an aluminum plastic film.

As a preferable technical solution of the present invention, the method for packaging and filling liquid into a soft-package wound battery includes the steps of:

(1) carrying out top sealing and side sealing on the winding core, and reserving an air bag at the bottom of the winding core as a liquid injection port;

(2) vertically downwards arranging the head of the winding core, and injecting liquid from a bottom liquid injection port;

(3) and (3) after the liquid injection in the step (2) is finished, performing bottom sealing on the bottom of the roll core to obtain the soft package wound battery.

Compared with the prior art, the invention has the following beneficial effects:

(1) in the packaging and liquid injection process of the soft package winding battery, the liquid injection port is arranged at the bottom of the winding core, the head of the winding core is vertically and downwards placed in the liquid injection process, and when liquid injection is started, electrolyte flows from the bottom of the winding core along the gap of the pole piece of the winding core and the gap between the pole piece and the diaphragm, so that the electrolyte reaches the head of the winding core far away from the liquid injection port, and the pole piece of the winding core is soaked by the electrolyte from the bottom to the head in the liquid discharging process of the electrolyte, so that the problem of poor soaking of the pole piece of the winding core in the traditional packaging and liquid injection method is solved;

(2) in the process of packaging and filling liquid of the soft package wound battery, the head of the wide and thin winding core is placed downwards, so that the side stress condition of the winding core is reduced, the problem that the wide and thin winding core is close to an air bag to deform due to the influence of gravity caused by the fact that a diaphragm and a pole piece of the winding core are not completely bonded and shaped before degassing of the winding core is finished is solved, and the cycle life of the soft package wound battery obtained by packaging is prolonged.

Drawings

Fig. 1 is a schematic structural view of a pouch wound battery in example 1 of the present invention;

fig. 2 is a schematic diagram of the absorption direction and the discharging direction of the electrolyte in the liquid injection process of the soft-package wound battery in embodiment 1 of the invention;

fig. 3 is a schematic view of the structure of a pouch wound battery in comparative example 1 of the present invention;

fig. 4 is a schematic view showing the direction of adsorption and the direction of discharge of the electrolyte during the charging of the pouch wound battery in comparative example 2 of the present invention.

1-roll core, 2-air bag, 3-liquid filling port, and A-roll core pole piece deformation area.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.