A soft pack secondary battery

Abstract

The present invention provides a soft-pack secondary battery, which relates to the technical field of secondary batteries. The packaging structure is composed of two layers of aluminum-plastic film materials, and the surfaces of the aluminum-plastic film materials are each provided with a plurality of reserved cavities, and two corresponding reserved cavities form an accommodating cavity; there are a plurality of battery cells, which are respectively arranged in each accommodating cavity; a stamping area is arranged on the surface of the packaging structure and is located at the periphery of the reserved cavity; an isolation area is arranged on the surface of the packaging structure and is located between the reserved cavities, and a safety area is provided in the center of the isolation area, and a plurality of holes are provided on the surface of the safety area; the aluminum-plastic film material is folded in a Z shape in multiple layers along the safety area, and the battery cell array is folded with the safety area as the folding line. It only needs to go through the steps of punching, placing the battery cells, encapsulating the battery cells, and folding the battery cells to form a group. The production equipment can be arranged on an assembly line, and there is no need to transfer the battery cells multiple times.

Description

Technical Field

[0001] The present invention relates to the field of secondary batteries, and in particular to a soft-pack secondary battery. Background Art

[0002] As an important part of new energy vehicles, lithium-ion batteries are attracting increasing attention. Currently, widely used lithium-ion battery systems are increasingly unable to meet customer needs, and continuous improvement and innovation are needed in both mass energy density and volume energy density.

[0003] Existing soft-pack lithium-ion batteries mainly use aluminum-plastic packaging film as the packaging material. Generally speaking, soft-pack lithium-ion batteries are encapsulated between two layers of aluminum-plastic film with pits through a hot pressing process, and then the four sides are hot-pressed and sealed. Since all four sides need to be sealed, it is necessary to reserve the packaging size. Therefore, the operation steps are cumbersome and there are many processes, which to some extent affects the efficiency of battery cell production.

[0004] Secondly, the battery cells after edge sealing are all independent individuals. When the battery cells are grouped later, they need to be arranged in order and then glued together with glue. After the battery cells are made, they are transferred to the grouping process, which is a cumbersome process. Summary of the Invention

[0005] The purpose of the present invention is to provide a soft-pack secondary battery to solve the above technical problems. To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A soft-pack secondary battery comprising

[0007] The packaging structure is composed of two layers of aluminum-plastic film materials, and a plurality of reserved cavities are provided on the surface of the aluminum-plastic film materials, and two corresponding reserved cavities form a receiving cavity;

[0008] There are several battery cells, each of which is respectively arranged in each receiving cavity;

[0009] A stamping area is provided on the surface of the packaging structure and is located outside the reserved cavity;

[0010] An isolation area is provided on the surface of the packaging structure and is located between the reserved cavities. A safety area is provided in the center of the isolation area, and a plurality of holes are provided on the surface of the safety area.

[0011] The aluminum-plastic film is folded in multiple layers in a Z-shape along the safety zone, and the battery cells overlap each other;

[0012] With this design, after the battery cells and packaging structure are packaged, they can enter the stacking process, which speeds up battery manufacturing efficiency.

[0013] A further preferred solution is that two tabs are provided at the outer end of the cell, the tabs pass through the packaging structure, and insulating glue is affixed to the position where the tabs pass through the packaging structure;

[0014] This design protects the connection between the tab and the packaging structure through insulating glue to avoid leakage.

[0015] A further preferred solution: the isolation area and the accommodating cavity are divided into a single-layer composite structure and a double-layer structure with the stamping area as the boundary, the isolation area is a single-layer composite structure, and the accommodating cavity is a double-layer structure;

[0016] Furthermore: the width of the isolation area is ≥ one third of the width of the accommodating cavity;

[0017] A further preferred embodiment: the thickness of the isolation region is 210 μm-280 μm;

[0018] This design accommodates the battery cells through the accommodating cavity and strengthens the firmness of the packaging structure through the isolation area.

[0019] A further preferred solution is that the thickness of the safety zone is less than the thickness of the isolation zone, and the holes on the surface of the safety zone are formed by punching with a punching device, and the inner diameter of the holes is 20 μm-700 μm;

[0020] Several reinforcement points are formed through the holes.

[0021] A further preferred solution is that an isolation membrane is provided between the folded layers of the battery cell monomers.

[0022] Beneficial effects of the present invention:

[0023] 1. Punch holes in the aluminum-plastic film, insert the battery cells, and encapsulate the battery cells. The battery cells will be arranged side by side and connected by the aluminum-plastic film. The battery cells form an integrated structure.

[0024] 2. The battery cells are arranged horizontally and connected. A conveyor belt can be used to uniformly transport the battery cell array to the folding process. The transmission is convenient and fast. Compared with the traditional independent battery cell transfer, it is more convenient. The battery cell array is folded in a Z shape by the folding equipment. One battery cell is a layer. Those skilled in the art can design the number of battery cell layers according to the size of the battery module. The battery cell array is folded with the safety zone as the folding line. It only needs to go through the steps of punching, battery cell placement, battery cell packaging, and battery cell folding to form a group. The production equipment can be set on a production line. There is no need to transfer battery cells multiple times, making the production of battery packs more continuous. The packaging structure between battery cells does not need to be cut, reducing the operation steps and improving the processing efficiency.

[0025] 3. When holes are punched on the surface of the safety zone and cracks and damage occur in the isolation zone, the cracks expand to a certain extent and extend to the holes. The holes block the cracks at their location, making it difficult for the cracks to spread further. The traditional single-layer planar packaging structure lacks a crack blocking structure, and the area of ​​crack diffusion will become larger and larger, which can easily cause the safety zone to break and lead to the dispersion of the battery cell module. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the assembly of the battery cell and aluminum-plastic film structure of the present invention (the battery cell has a single-end terminal ear shape);

[0027] Figure 2 This is a schematic diagram of the assembly of the battery cell and the aluminum-plastic film structure of the present invention (the battery cell has double-ended terminal ears);

[0028] Figure 3 This is a schematic diagram of the assembly of the battery cell and the aluminum-plastic film structure of the present invention;

[0029] Figure 4 For the present invention Figure 3 A local enlarged structural diagram in FIG.

[0030] Figure 5 This is a schematic diagram of the soft pack battery structure stack of the present invention;

[0031] Figure 6 Schematic diagram of the soft pack battery structure stacking of the present invention.

[0032] In the figure: aluminum-plastic film (1), reserved cavity (2), battery cell (3), stamping area (4), isolation area (5), safety area (6), isolation membrane (7). Implementation Method

[0033] See also Figures 1-4 , a soft-pack secondary battery, comprising:

[0034] The packaging structure consists of two layers of aluminum-plastic film 1. In the initial state, the aluminum-plastic film 1 is in a roll shape, and in order to facilitate battery production, the two rolls of aluminum-plastic film 1 should be arranged vertically up and down;

[0035] A plurality of reserved cavities 2 are provided on the surface of the aluminum-plastic film material 1. Two rolls of aluminum-plastic film material 1 are respectively input into the punching equipment for punching. After punching, the reserved cavities 2 are formed, and each reserved cavity 2 is arranged at equal distances. The reserved cavities 2 between the two rolls of aluminum-plastic film material 1 are arranged up and down, and a receiving cavity is formed between the upper and lower corresponding reserved cavities 2. After the aluminum-plastic film material 1 is punched, the battery cells 3 are placed one by one in the reserved cavity 2 located below. At the same time, the two rolls of aluminum-plastic film material 1 and the battery cells 3 are transported together, and the battery cells 3 are transported to the tab welding section, and the tabs are welded to the tab connection area of ​​the battery cells 3.

[0036] Furthermore, the stamping area 4 is provided on the surface of the packaging structure and is located outside the reserved cavity 2. The aluminum-plastic film material 1 and the battery cell monomer 3 are transported to the stamping position together. The two layers of aluminum-plastic film material 1 are stamped together by the stamping equipment. At the same time, the two upper and lower corresponding reserved cavities 2 are combined, and the battery cell monomer 3 is packaged in the accommodating cavity. In order to facilitate the later liquid injection, two openings should be reserved when packaging the accommodating cavity, one opening as the liquid injection hole, and the other opening as the exhaust hole. The accommodating cavity is injected with liquid, and the gas inside the accommodating cavity is discharged from the opening. After the liquid injection is completed, the secondary stamping package is performed to seal the reserved opening. At the same time, the area of ​​the secondary stamping is larger (such as Figure 2 and Figure 3 As shown in the figure, the isolation area 5 is formed by secondary stamping and is arranged on the surface of the packaging structure and between the reserved cavities 2. The isolation area 5 and the accommodating cavity are separated by the stamping area 4 and are divided into single-layer composite and double-layer structures. The isolation area 5 is a single-layer composite structure, and the accommodating cavity is a double-layer structure. After the isolation area 5 is stamped, adjacent accommodating cavities are not connected, and the width of the isolation area 5 is ≥ one-third of the width of the accommodating cavity. The large area of ​​the isolation area 5 can prevent air leakage and liquid leakage in the accommodating cavity. The above is the completion of the liquid filling work;

[0037] A safety zone 6 is provided in the center of the isolation zone 5, and a plurality of holes (such as Figure 4 As shown), the holes are formed by punching equipment, and the holes are in the shape of through holes;

[0038] According to the above method, the aluminum-plastic film material 1 is punched, the battery cells 3 are placed and the battery cells 3 are packaged. The battery cells 3 are arranged in parallel (such as Figure 3 As shown), and connected by the aluminum-plastic film material 1, the battery cells 3 are an integrated structure;

[0039] Specifically, after the above steps, the two tabs in the battery cell 3 will pass through the packaging structure, and the position where the tabs pass through the packaging structure is affixed with insulating glue, which can ensure the sealing of the accommodating cavity and isolate the power transmission position of the tabs to avoid poor operation of the battery cell 3 in the later stage.

[0040] See also Figures 1-6 , steps for folding the battery cell 3 into groups:

[0041] After the above steps, the battery cells 3 enter the grouping process. Because the battery cells 3 are arranged horizontally and connected, a conveyor belt can be used to uniformly transport the battery cell 3 array to the folding process. The transportation is convenient and fast, which is more convenient than the traditional transfer of independent battery cells 3.

[0042] The array of battery cells 3 is folded into a Z shape by a folding device, with one battery cell 3 being a layer. Those skilled in the art can design the number of layers of the battery cell 3 according to the size of the battery module, and the array of battery cells 3 is folded with the safety zone 6 as the folding line. The thickness of the isolation zone 5 is 210 μm-280 μm. Because the plastic material in the aluminum-plastic film 1 is squeezed when the surface of the safety zone 6 is punched, the thickness of the safety zone 6 is less than the thickness of the isolation zone 5. The thickness of the isolation zone 5 is preferably 250 μm. After punching, the thickness of the safety zone 6 is 180 μm-200 μm. The folding process of the safety zone 6 is convenient and can be easily bent to form a group with the battery cells 3.

[0043] The inner diameter of the hole is 20μm-700μm. The smaller the inner diameter of the hole, the less likely it is to damage the strength of the packaging structure. In addition, multiple holes form multiple reinforcing ribs. When cracks or damage occur in the isolation area 5, the cracks extend to a certain extent and extend to the holes. The holes block the cracking position, making it difficult for the cracks to spread further. The traditional single-layer planar packaging structure lacks a crack blocking structure, and the area of ​​crack spread will become larger and larger, which can easily cause the safety area 6 to break and lead to the dispersion of the battery module.

[0044] Furthermore, an isolation film 7 (such as Figure 5 and Figure 6 As shown), a separator 7 is placed in the interlayer of the battery cell 3 by mechanical equipment. A layer of separator 7 is provided between each layer of the battery cell 3. The separator 7 is preferably made of PET sponge material. The battery cell 3 is separated by the separator 7 to protect each layer of the battery cell 3 from being scratched and to prevent the battery cell 3 layers from being close to each other, resulting in poor heat dissipation. In summary, the performance of the battery pack is improved.

[0045] The soft-pack secondary battery can be grouped only after punching, placing the battery cell 3, packaging the battery cell 3, and folding the battery cell 3. The production equipment can be set on an assembly line, and there is no need to transfer the battery cells multiple times, making the production of the battery pack more continuous, and the packaging structure between the battery cell 3 does not need to be cut, reducing the operation steps and improving the processing efficiency.

Claims

1. A soft-pack secondary battery, characterized in that: include The packaging structure is composed of two layers of aluminum-plastic film materials, and a plurality of reserved cavities are provided on the surface of the aluminum-plastic film materials, and two corresponding reserved cavities form a receiving cavity; There are several battery cells, each of which is respectively arranged in each receiving cavity; A stamping area is provided on the surface of the packaging structure and is located outside the reserved cavity; An isolation zone is provided on the surface of the packaging structure and between the reserved cavities. A safety zone is provided in the center of the isolation zone, and a plurality of holes are provided on the surface of the safety zone. The isolation zone and the accommodating cavity are divided into a single-layer composite structure and a double-layer structure with the stamping zone as the boundary. The isolation zone is a single-layer composite structure, and the accommodating cavity is a double-layer structure. The width of the isolation zone is ≥ one-third of the width of the accommodating cavity. The aluminum-plastic film material is folded in multiple layers in a Z-shape along the safety zone, and the battery cells are overlapped with each other.

2. The soft-pack secondary battery according to claim 1, characterized in that: Two tabs are provided at the outer end of the battery cell. The tabs pass through the packaging structure, and insulating glue is affixed to the position where the tabs pass through the packaging structure.

3. The soft-pack secondary battery according to claim 1, characterized in that: The thickness of the isolation region is 210 μm-280 μm.

4. The soft-pack secondary battery according to claim 1, characterized in that: The thickness of the safety zone is less than the thickness of the isolation zone, and the holes on the surface of the safety zone are formed by punching with a punching device, and the inner diameter of the holes is 20 μm-700 μm.

5. The soft-pack secondary battery according to claim 1, characterized in that: An isolation film is provided between the folded layers of the battery cell monomers.

Images