CN108428809A - Soft-package battery - Google Patents

Abstract

The present invention provides a kind of soft-package batteries comprising two layers of packaging film and the battery core being encapsulated between two layers of packaging film.Each layer packaging film includes external protection, interior fused layer and the metal layer between external protection and interior fused layer.Two layers of packaging film forms the main part of receiving battery core at middle part, is tightly connected around main part and forms closedtop portion and side seal portion, wherein side seal portion bends and is bonded on the side of main part.Each layer packaging film is divided into ontology and free end in side seal portion, and free end is folded back on corresponding ontology；Expose metal layer on the end face of each free end, the free end of two layers of packaging film is fixed together and is clamped between the ontology of two layers of packaging film.The soft-package battery of the present invention can utilize inflection structure of each layer packaging film in side seal portion to realize the insulated enclosure of the metal layer exposed on end face, and edge sealing effect is improved to simplify the edge sealing process of soft-package battery without using other edging materials.

Description

Soft pack battery

technical field

The invention relates to the field of batteries, in particular to a soft pack battery.

Background technique

Soft-pack lithium-ion batteries currently mainly use aluminum-plastic composite film for cell packaging. The aluminum-plastic film is mainly divided into a three-layer structure of a protective layer, a metal layer and a fusion layer. After packaging and edge trimming during packaging, the metal layer at the edge of the package cannot be wrapped and exposed, which may easily lead to problems such as short circuits.

At present, the edge sealing structure of the battery mainly includes two kinds of structure, the single folding edge structure and the double folding edge structure. The single folded edge structure of the rubber wrapping is to paste the insulating tape on the edge of the battery package, and then use the mechanical method to fold up the package edge and paste it on the side of the main body of the cell; the double folded edge structure is to expose the package edge to the edge of the metal layer Fold it onto the package side body, then fold up the package side body and bond it to the battery core body, and clamp the edge of the exposed metal layer between the package side body and the battery core body through two folds.

Both edge-sealing structures can solve the problem of exposed aluminum in conventional batteries, but they also have their own limitations, especially when the edge-sealing treatment of non-rectangular batteries is performed on non-linear edges. On the one hand, For non-straight edges, the insulating tape cannot completely cover the edge of the packaging edge, and there is a risk of aluminum exposure. For curved edges such as rounded corners, there are problems such as tape wrinkling and overlapping, causing appearance defects, and after a certain period of use, The tape may be warped or turned at the beginning and end, causing appearance defects and the risk of aluminum exposure; For the folded edge structure, the double folded edge process is cumbersome, and at the same time increases the width of the battery, which may easily cause the size to exceed the specification.

Contents of the invention

In view of the problems existing in the background technology, the object of the present invention is to provide a pouch battery, which can simplify the edge-sealing process and improve the edge-sealing effect.

In order to achieve the above object, the present invention provides a soft pack battery, which includes two layers of packaging films and an electric core packaged between the two layers of packaging films. Each layer of packaging film includes an outer protection layer, an inner fusion layer and a metal layer between the outer protection layer and the inner fusion layer. The two-layer packaging film forms a main body for storing batteries in the middle, and seals and connects around the main body to form a top seal and a side seal, wherein the side seal is bent and bonded to the side of the main body. Each layer of packaging film is divided into a body and a free end on the side seal, and the free end is folded back to the corresponding body; the metal layer is exposed on the end surface of each free end, and the free ends of the two layers of packaging film are fixed together and clamped between the two Between the body of the layer wrapping film.

The beneficial effects of the present invention are as follows:

In the pouch battery according to the present invention, the free ends of each layer of packaging film on the side seal are clamped between the bodies of the two layers of packaging films, so that the exposed metal layer on the end surface is directly exposed by the bodies of the two layers of packaging films. Insulation and sealing, therefore, the pouch battery of the present invention can utilize the folding structure of each layer of packaging film on the side sealing part to realize the insulation and sealing of the metal layer exposed on the end surface, without using other edge sealing materials, thereby simplifying the pouch battery. Edge banding process improves the effect of edge banding.

Description of drawings

Fig. 1 is a schematic diagram of the packaging film of the pouch battery according to the present invention;

Fig. 2 is a sectional view taken along the centerline C of Fig. 1;

Fig. 3 is a schematic diagram of the pouch battery according to the present invention before molding;

Fig. 4 is another schematic diagram of the pouch battery according to the present invention before molding;

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

Fig. 6 is an enlarged view of the dotted frame in Fig. 5;

FIG. 7 is a schematic view of the formed pouch battery according to the present invention.

Wherein, the reference signs are explained as follows:

1 Top seal P3 metal layer

2 Side seal G glue

21 Body S Recess

22 Free end B Cell

221 End face B1 tab

3 Main body W width direction

31 Side L Length direction

P Packaging film T Thickness direction

P1 Outer protective layer C Centerline

P2 inner fusion layer

Detailed ways

The pouch battery of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 to FIG. 7 , the pouch battery according to the present invention includes two layers of packaging film P and a battery cell B packaged between the two layers of packaging film P. Each layer of packaging film P includes an outer protective layer P1, an inner fusion layer P2, and a metal layer P3 located between the outer protection layer P1 and the inner fusion layer P2. The two-layer packaging film P forms the main body part 3 in the middle to accommodate the battery B, and is sealed and connected around the main body part 3 to form a top seal part 1 and a side seal part 2, wherein the side seal part 2 is bent and bonded to the main body On the side 31 of the part 3. Each layer of packaging film P is divided into a body 21 and a free end 22 on the side sealing part 2, and the free end 22 is folded back to the corresponding body 21; the metal layer P3 is exposed on the end surface 211 of each free end 22, and the two layers of packaging film P The free ends 22 are fixed together and clamped between the bodies 21 of the two packaging films P.

In the pouch battery according to the present invention, the free end 22 of each layer of packaging film P on the side sealing part 2 is clamped between the bodies 21 of the two layers of packaging film P, so that the metal layer P3 is exposed directly on the end surface 211. The body 21 of the two-layer packaging film P is insulated and sealed. Therefore, the pouch battery of the present invention can utilize the folding structure of each layer of packaging film P on the side sealing part 2 to realize the insulation and sealing of the metal layer P3 exposed on the end surface 211 without Use other edge-sealing materials (such as insulating tape) to simplify the edge-sealing process of the pouch battery (that is, the process of insulating and sealing the metal layer P3 exposed from the packaging film P) and improve the edge-sealing effect.

For non-rectangular pouch batteries, the above structure can also be used to achieve edge sealing. For example, for pouch batteries with curved edges, since this method does not require insulating tape, problems such as wrinkling and overlapping caused by the use of insulating tape can be avoided.

In the pouch battery according to the present invention, the inner fusion layer P2 is polypropylene, the outer protective layer P1 is nylon, and the metal layer P3 is aluminum foil or steel foil.

In the pouch battery according to the present invention, referring to FIG. 7 , the side seal portion 2 is adhered to the side surface 31 of the main body portion 3 by an adhesive G. Referring to FIG. Adhesive G can be materials such as glue, gummed paper.

In the pouch battery according to the present invention, referring to FIG. 7 , a cavity S for accommodating the cell B is formed on a layer of packaging film P, and the body 21 of the layer of packaging film P on the side seal portion 2 is bonded to the main body. On the side 31 of the part 3. Stamping is performed on the one layer of packaging film P to form a concave cavity S. The side 31 of the main body 3 is also the corresponding outer wall of the concave cavity S punched out by the layer of packaging film P.

In the pouch battery according to the present invention, referring to FIGS. 5 to 7 , the inner fusion layer P2 at the free end 22 of the packaging film P is fused with the inner fusion layer P2 at the body 21 . The inner fusion layer P2 is generally a hot-melt plastic material (polypropylene), so after the free end 22 of the packaging film P is folded back, the inner fusion layer P2 at the free end 22 is directly opposite to the inner fusion layer P2 at the body 21. Hot pressing can fixedly connect the free end 22 with the corresponding body 21 .

In the pouch battery according to the present invention, the free ends 22 of the two packaging films P are bonded together by glue. Since the two layers of packaging film P are facing each other up and down, the outer protective layer P1 of the two layers of packaging film P at the free end 22 is directly opposite, and the outer protective layer P1 (nylon) generally does not have heat-meltability, so it is necessary to realize the two layers by glue. The fixed connection of the free end 22 of the layer packaging film P.

In the pouch battery according to the present invention, referring to FIG. 7 , the inner fusion layers P2 of the directly opposite parts of the two bodies 21 are fused together. Since the two-layer packaging film P is facing up and down, the inner fusion layers P2 of the two main bodies 21 on the side seal part 2 of the two-layer packaging film P are facing up and down (except the part where the main body 21 is covered by the corresponding free end 22), by hot pressing The inner fusion layer P2 in the directly opposite parts of the two main bodies 21 may be fused together.

In the pouch battery according to the present invention, referring to FIG. 7 , the height of the side sealing portion 2 along the thickness direction T is smaller than the height of the side surface 31 . Avoid the side seal portion 2 occupying the space of the pouch battery in the thickness direction T, and prevent the energy density of the pouch battery from being reduced due to the side seal portion 2 being too high.

In the pouch battery according to the present invention, the two-layer packaging film P is two independent packaging films. Wherein, a concave cavity S is punched out on one packaging film, and the other packaging film is sealed and connected with the one packaging film around the concave cavity S to form a top sealing part 1 and a side sealing part 2 .

In the pouch battery according to the present invention, referring to FIG. 1 to FIG. 4 , the two-layer packaging film P is one packaging film, and the one packaging film P is folded in half to form two connected packaging films P. A concave cavity S is punched out on the one packaging film, and then folded in half to seal the concave cavity S, and at the same time, two layers of packaging films P are connected.

In the pouch battery according to the present invention, referring to FIG. 4 , the tab B1 of the cell B protrudes from the top seal portion 1 .

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

1) With reference to Fig. 1 and Fig. 2, fold back the free end 22 of a piece of packaging film P along the two ends of the width direction W that exposes the metal layer P3, so that the inner fusion layer P2 of the free end 22 and the inner fusion layer of the packaging film P substrate P2 bonding, and then the free end 22 is fused with the substrate of the packaging film P by hot pressing;

2) Referring to Figure 3, punch a hole in the part of the packaging film P on the side of the center line C to form a cavity S, and place the battery B in the cavity S;

3) Referring to Figures 4 to 6, apply glue on the free end 22, then fold the part of the packaging film P on the other side of the centerline C to close the cavity S, and after folding the entire packaging film P It is divided into upper and lower layers, and the opposite free ends 22 of the two-layer packaging film P are bonded together, wherein the part of the two-layer packaging film P surrounding the battery cell B is the main part 3;

4) With reference to Fig. 7, the part of the two-layer packaging film P around the main body 3 that is in direct contact is hot-pressed, and side seals 2 are formed on both sides of the main body 3 along the width direction W, and on the sides of the main body 3 along the length direction L One side forms the top seal part 1, and the tab B1 of the cell B protrudes through the top seal part 1; then apply adhesive G on the side seal part 2, and then bend the side seal part 2 to bond the side seal part 2 On the side surface 31 of the main body part 3 .

Claims (10)

1. a kind of soft-package battery, including two layers of packaging film (P) and the battery core (B) that is encapsulated between two layers of packaging film (P)；

Each layer packaging film (P) includes external protection (P1), interior fused layer (P2) and positioned at external protection (P1) and interior fused layer (P2) metal layer (P3) between；

Two layers of packaging film (P) forms the main part (3) of receiving battery core (B) at middle part, is tightly connected simultaneously around main part (3) It is formed closedtop portion (1) and side seal portion (2), wherein side seal portion (2) bend and are bonded on the side (31) of main part (3)；

It is characterized in that,

Each layer packaging film (P) is divided into ontology (21) and free end (22) on side seal portion (2), and free end (22) are folded back to correspondence Ontology (21) on；Expose metal layer (P3), the free end of two layers of packaging film (P) on the end face (211) of each free end (22) (22) it is fixed together and is clamped between the ontology (21) of two layers of packaging film (P).

2. soft-package battery according to claim 1, which is characterized in that interior fused layer (P2) is polypropylene, external protection (P1) it is nylon, metal layer (P3) is aluminium foil or steel foil.

3. soft-package battery according to claim 1, which is characterized in that side seal portion (2) are adhered to main body by bonding agent (G) On the side (31) in portion (3).

4. soft-package battery according to claim 1, which is characterized in that be formed with receiving battery core (B) on one layer of packaging film (P) Cavity (S), and ontology (21) of this layer of packaging film (P) on side seal portion (2) is bonded on the side (31) of main part (3).

5. soft-package battery according to claim 1, which is characterized in that interior fusion of the packaging film (P) at free end (22) Layer (P2) is merged with the interior fused layer (P2) at ontology (21).

6. soft-package battery according to claim 1, which is characterized in that the free end (22) of two layers of packaging film (P) passes through glue Water bonds together.

7. soft-package battery according to claim 1, which is characterized in that two ontologies (21) are merged in directly opposite part Layer (P2) is merged.

8. soft-package battery according to claim 1, which is characterized in that the height of side seal portion (2) through-thickness (T) is less than The height of side (31).

9. soft-package battery according to claim 1, which is characterized in that two layers of packaging film (P) is independent Liang Zhangbao Fill film.

10. soft-package battery according to claim 1, which is characterized in that two layers of packaging film (P) is a packaging film, Two layers of connected packaging film (P) is formed after one packaging film doubling.