CN108428814B

CN108428814B - Packaging film and soft pack battery

Info

Publication number: CN108428814B
Application number: CN201710080426.6A
Authority: CN
Inventors: 林森; 何平; 谢斌; 郭培培; 张亚杰; 殷科
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2017-02-15
Filing date: 2017-02-15
Publication date: 2021-09-07
Anticipated expiration: 2037-02-15
Also published as: CN108428814A

Abstract

The invention provides a packaging film and a soft-pack battery. The packaging film includes an outer protective layer, an inner fusion layer, and a metal layer between the outer protective layer and the inner fusion layer. Wherein, at least one outer end face of the inner fusion layer at the edge exceeds the corresponding outer end face of the metal layer. The soft pack battery includes: an electric core; and two upper and lower layers of packaging films, the two layers of packaging films enclose an inner cavity for accommodating the electric core in the middle, and are sealed and connected around the inner cavity. Wherein, on each layer of packaging film, the portion of the inner fusion layer beyond the corresponding outer end surface of the metal layer is folded back onto the outer protective layer to cover the corresponding outer end surface of the metal layer. On each layer of packaging film, the part of the inner fusion layer beyond the corresponding outer end surface of the metal layer can be folded back to cover the corresponding outer end surface of the metal layer, thereby insulating and sealing the metal layer. Therefore, the pouch battery of the present invention can utilize its own The structure realizes the insulating sealing of the outer end face without using other edge sealing materials, thereby simplifying the edge sealing process of the soft pack battery and improving the edge sealing effect.

Description

Packaging film and soft package battery

Technical Field

The invention relates to the field of batteries, in particular to a packaging film and a soft package battery.

Background

At present, the soft package lithium ion battery mainly adopts an aluminum-plastic composite film to package a battery cell, and the aluminum-plastic film is mainly divided into a protective layer, a metal layer and a fusion layer. After encapsulation and trimming during packaging, the metal layer at the edge of the encapsulated edge can not be wrapped and exposed, which easily causes the problems of short circuit and the like.

At present, the edge sealing structure of the battery edge mainly has two structures, namely an encapsulation single-folding edge structure and a double-folding edge structure. The encapsulation single-folding structure is that an insulating adhesive tape is pasted on the edge of the battery encapsulation edge, and then the encapsulation edge is folded and pasted on the side edge of the battery core main body by adopting a mechanical method; the double-folding structure is that the edge of the packaging edge exposed out of the metal layer is folded onto the packaging edge body, then the packaging edge body is folded and adhered to the battery cell main body, and the edge exposed out of the metal layer is clamped between the packaging edge body and the battery cell main body through two times of folding.

The two edge sealing structures can solve the problem of aluminum exposure of the conventional battery at present, but have larger self limitations, particularly the limitation is more obvious when the edge sealing treatment is carried out on the non-linear edge of the non-rectangular battery, on one hand, for the non-linear edge, the edge of the packaging edge cannot be completely coated by the insulating adhesive tape, the risk of aluminum exposure exists, for the arc-shaped edges such as round corners and the like, the problems of wrinkling, overlapping and the like of the adhesive tape exist, the appearance defect is caused, and after the non-linear edge sealing structure is used for a certain time, the adhesive tape can be warped or turned over at the starting position and the ending position, and the appearance defect and the risk of aluminum exposure are caused; on the other hand, for the rubber-coated single-folded edge structure, materials such as an adhesive tape and the like need to be added, and a rubber sticking process needs to be added; for the double-folding structure, the two-folding process is complicated, the width of the battery is increased, and the size is easy to exceed the specification.

Disclosure of Invention

In view of the problems in the prior art, an object of the present invention is to provide a packaging film and a pouch battery, which can simplify the edge sealing process of the pouch battery and improve the edge sealing effect.

In order to achieve the above object, in a first aspect, the present invention provides a packaging film comprising an outer protective layer, an inner fusion layer, and a metal layer between the outer protective layer and the inner fusion layer. Wherein at least one outer end face of the inner fusion layer at the edge exceeds a corresponding outer end face of the metal layer.

In order to achieve the above object, in a second aspect, the present invention provides a pouch battery comprising: an electric core; the two layers of packaging films enclose an inner cavity for accommodating the battery cell in the middle and are hermetically connected with the periphery of the inner cavity. On each layer of packaging film, the part of the inner fusion layer, which exceeds the corresponding outer end face of the metal layer, is folded back onto the outer protection layer so as to coat the corresponding outer end face of the metal layer.

The invention has the following beneficial effects:

in the packaging film and the soft package battery, on each layer of packaging film, the part of the inner fusion layer, which exceeds the corresponding outer end face of the metal layer, can be folded back to cover the corresponding outer end face of the metal layer, so that the metal layer is insulated and sealed.

Drawings

FIG. 1 is a schematic view of a packaging film according to the present invention;

FIG. 2 is another schematic view of a packaging film according to the present invention;

FIG. 3 is a schematic view of a packaging film according to the present invention after being dimpled;

fig. 4 is a schematic diagram of a pouch cell according to the present invention;

FIG. 5 is a cross-sectional view taken along line A-A of FIG. 4;

fig. 6 is a schematic diagram of a pouch battery forming process according to the present invention;

fig. 7 is another schematic diagram of the pouch battery forming process according to the present invention;

fig. 8 is another schematic view of a pouch battery according to the present invention.

Wherein the reference numerals are as follows:

1 packaging film B electric core

11 outer protective layer B1 tab

111 outer end surface M cavity

Side wall of 12 inner fusion layer M1

Glue G on outer end face of 121

13 width direction of metal layer W

131 outer end face L in the length direction

S packaging edge

Detailed Description

The packaging film and pouch battery according to the present invention will be described in detail with reference to the accompanying drawings

First, a packaging film according to a first aspect of the present invention is explained.

Referring to fig. 1 to 8, a packaging film 1 according to the present invention includes an outer protective layer 11, an inner fusion layer 12, and a metal layer 13 between the outer protective layer 11 and the inner fusion layer 12. Wherein at least one outer end face 121 of the inner fusion layer 12 at the edge exceeds the corresponding outer end face 131 of the metal layer 13.

In the packaging film 1 according to the present invention, since at least one outer end face 121 of the inner fusion layer 12 at the edge exceeds the corresponding outer end face 131 of the metal layer 13, the portion of the inner fusion layer 12 exceeding the corresponding outer end face 131 of the metal layer 13 can be folded back to cover the metal layer 13, so as to prevent the outer end face 131 of the metal layer 13 from being exposed, and prevent a pouch cell to which the packaging film 1 is applied from short-circuiting.

In the packaging film 1 according to the present invention, the inner fusion layer 12 is polypropylene, the outer protection layer 11 is nylon, and the metal layer 13 is aluminum foil or steel foil.

In the packaging film 1 according to the present invention, referring to fig. 1, 2, 5 to 8, the outer end face 111 of the outer protective layer 11 is flush with the outer end face 131 of the corresponding metal layer 13.

In the packaging film 1 according to the present invention, referring to fig. 1, 5 to 8, both outer end faces 121 of the inner fusion layer 12 in the width direction W respectively exceed the corresponding outer end faces 131 of the metal layer 13.

In the packaging film 1 according to the present invention, referring to fig. 2, the outer end faces 121 on the periphery of the inner fusion layer 12 each exceed the corresponding outer end face 131 of the metal layer 13.

Next, a pouch battery according to a second aspect of the present invention will be described.

Referring to fig. 1 to 8, the pouch battery according to the present invention includes: a battery core B; and the two layers of the packaging films 1 enclose an inner cavity M for accommodating the battery core B in the middle part, and the peripheries of the inner cavity M are hermetically connected. Wherein, on each layer of packaging film 1, the portion of the inner fusion layer 12 beyond the corresponding outer end face 131 of the metal layer 13 is folded back onto the outer protection layer 11 to cover the corresponding outer end face 131 of the metal layer 13.

In the soft package battery according to the present invention, on each layer of the packaging film 1, the portion of the inner fusion layer 12 beyond the corresponding outer end surface 131 of the metal layer 13 may be folded back to wrap the corresponding outer end surface 131 of the metal layer 13, so as to insulate and seal the metal layer 13, and therefore, the soft package battery according to the present invention may use its own structure to realize the insulation and sealing of the outer end surface 131, and does not need to use other edge sealing materials (such as an insulating tape), thereby simplifying the edge sealing process of the soft package battery (without using adhesive tape sticking equipment and procedures), and improving the edge sealing effect.

Meanwhile, for a non-rectangular soft package battery, the edge sealing (i.e. insulating and sealing the metal layer 13) can also be realized in this way. For example, for a soft package battery with an arc-shaped edge, since an insulating tape is not needed in this way, the problems of wrinkling, overlapping and the like caused by the use of the insulating tape can be avoided.

In the pouch battery according to the present invention, referring to fig. 5 and 8, the portion of the inner fusion layer 12 folded back onto the outer protective layer 11 is bonded to the outer protective layer 11 by glue.

In the pouch battery according to the present invention, referring to fig. 4 to 8, the two-layer packaging film 1 forms a plurality of sealing edges S at the sealing connection of the periphery of the inner cavity M, and the inner fusion layers 12 of the directly opposite portions of the two-layer packaging film 1 are fused together (by heat pressing) at the sealing edges S.

In the pouch battery according to the present invention, referring to fig. 8, among the plurality of sealing edges S, two sealing edges S are located at both sides of the inner cavity M in the width direction W, and the two sealing edges S are bent and adhered to the side wall M1 of the inner cavity M. Through buckling two encapsulation limit S, can reduce laminate polymer battery 'S whole width, improve laminate polymer battery' S energy density. At this time, it is preferable that the two outer end surfaces 121 of the inner fusion layer 12 of the two-layer packaging film 1 in the width direction W respectively exceed the corresponding outer end surfaces 131 of the metal layer 13, so that both of the two sealing edges S can be sealed without using other sealing edge materials.

In the pouch battery according to the present invention, the shape of each packaging film 1 (i.e., which outer end faces 121 of the inner fusion layer 12 in each packaging film 1 need to exceed the corresponding outer end faces 131 of the metal layer 13) can be determined according to the number and position of the required edge seals in the pouch battery.

In the pouch battery according to the present invention, referring to fig. 4, among the plurality of sealing edges S, one sealing edge S is located at one side of the inner cavity M in the length direction L, and the tab B1 of the cell B protrudes from the one sealing edge S.

In an embodiment of the pouch battery according to the present invention, the upper and lower packaging films 1 are two independent packaging films. One of the packaging films is punched to form a pit, and the other packaging film is hermetically connected with the one of the packaging films at the periphery (four sealing edges S are formed), so that the pit is sealed (an inner cavity M is formed).

In another embodiment of the pouch battery according to the present invention, referring to fig. 3, the upper and lower packaging films 1 are formed by folding one packaging film in half. The method comprises the steps of punching pits on one piece of packaging film, folding the packaging film in half to seal the pits (forming an inner cavity M), and simultaneously forming two connected packaging films 1, wherein the two packaging films 1 are connected in a sealing mode at the edges to form three sealing edges S.

In the pouch battery according to the present invention, referring to fig. 5 to 8, a pit is punched in the upper packaging film 1, and the lower packaging film 1 closes the pit to form an inner cavity M in which the cell B is housed.

In the pouch battery according to the present invention, the two sealing edges S (the sealing edges S located on both sides of the cavity M in the width direction W) are bonded to the side wall M1 of the cavity M by the glue G.

In the pouch battery according to the present invention, the height of the two sealing edges S (sealing edges S located on both sides of the cavity M in the width direction W) is smaller than the height of the side wall M1 of the cavity M.

The following is a forming process of the pouch battery according to an embodiment of the present invention:

1) a piece of packaging film 1 shown in fig. 1 is adopted, and pits are punched on the packaging film 1 through a shell punching process (shown in fig. 3);

2) placing the battery core B into the pit, folding the packaging film 1 in half (forming an upper packaging film 1 and a lower packaging film 1), and then carrying out hot pressing on the packaging film 1 to form three packaging edges S (refer to fig. 6);

3) folding back the part of the inner fusion layer 12 of the upper and lower packaging films 1, which exceeds the corresponding outer end face 131 of the metal layer 13, onto the outer protection layer 11 (refer to fig. 5 and 7);

4) the two sealing edges S located on both sides of the cavity M in the width direction W are bent and bonded to the side wall M1 of the cavity M (see fig. 8).

Claims

1. a soft pack battery, is characterized in that, comprises:

batteries; and

There are two upper and lower layers of packaging films, each layer of packaging film includes an outer protective layer, an inner fusion layer and a metal layer between the outer protection layer and the inner fusion layer, and at least one outer end face of the inner fusion layer at the edge exceeds the corresponding outer surface of the metal layer. On the end face, two layers of packaging film enclose an inner cavity for accommodating cells in the middle, and are sealed and connected around the inner cavity;

Wherein, on each layer of packaging film, the part of the inner fusion layer of this layer of packaging film beyond the corresponding outer end face of the metal layer of this layer of packaging film is folded back on the outer protective layer of this layer of packaging film to cover the layer of packaging film. The corresponding outer end face of the metal layer covers at least a part of the surface of the outer protective layer of the packaging film facing away from the metal layer of the packaging film.

2. The soft-pack battery according to claim 1, characterized in that, on each layer of packaging film, the part where the inner fusion layer of this layer of packaging film is folded back on the outer protective layer of this layer of packaging film and the layer of packaging film The outer protective layers are bonded together.

3. The soft-pack battery according to claim 1, wherein the two layers of packaging films form a plurality of packaging edges at the sealing joints around the inner cavity, and on the packaging edges, the inner fusion of the directly opposite parts of the two layers of packaging films layers are fused together.

4 . The soft pack battery according to claim 3 , wherein, among the plurality of packaging edges, two packaging edges are located on both sides of the inner cavity along the width direction, and the two packaging edges are bent. 5 . and glued to the side wall of the inner cavity.

5 . The soft pack battery according to claim 3 , wherein, among the plurality of packaging edges, one packaging edge is located on one side of the inner cavity along the length direction, and the tabs of the battery cells extend from the one side. 6 . protruding from the edge of the package.

6. The soft pack battery according to claim 1, characterized in that,

The upper and lower layers of packaging films are two independent packaging films; or

The upper and lower layers of packaging films are formed by folding one packaging film in half.

7 . The soft pack battery according to claim 1 , wherein the inner fusion layer is polypropylene, the outer protective layer is nylon, and the metal layer is aluminum foil or steel foil. 8 .

8 . The pouch battery according to claim 1 , wherein the outer end surface of the outer protective layer is flush with the outer end surface of the corresponding metal layer. 9 .

9 . The pouch battery according to claim 1 , wherein the two outer end faces of the inner fusion layer along the width direction respectively exceed the corresponding outer end faces of the metal layer. 10 .