Soft package battery cell with pressure relief structure

Abstract

The utility model provides a soft package battery cell with pressure relief structures, which relates to the technical field of batteries and comprises a shell, a groove is arranged on the surface of the shell, a bare battery cell is mounted in the groove, a plurality of pressure relief structures are arranged on the outer side of the groove, the shell is divided into a left part and a right part along a central line, the left part is a containing part, the right part is a covering part, and the groove is arranged on the containing part. The surface of the containing part and the periphery of the groove are adhesion areas, the covering part covers the containing part and is fixed with the adhesion areas in a thermoplastic manner, the surface of the covering part is provided with aluminum sheets corresponding to the grooves, the aluminum sheets are in contact with the naked battery cell, the number of the grooves is one or two, and the explosion-proof area plays a role in pressure relief on the side surface of the soft package battery cell. And the upper and lower large end faces of the soft package battery cell are not swelled or exploded, so that the safety performance of the module is greatly improved after the battery cells are grouped.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a soft-pack battery cell with a pressure relief structure. Background Technology

[0002] Lithium-ion batteries, as a popular energy storage device, mainly consist of a positive electrode, a negative electrode, an electrolyte, and a separator. Compared with traditional lead-acid and nickel-metal hydride batteries, they have higher energy density and advantages such as small size, long cycle life, and high manufacturability. Based on the different packaging forms, lithium-ion batteries are mainly divided into three types: cylindrical, prismatic hard-case, and pouch.

[0003] Hard-shell cells are more commonly used as power battery cells due to their relatively simple assembly structure, easier installation of explosion-proof valves, and better heat dissipation. However, hard-shell cells have lower energy density than pouch cells and are heavier, resulting in lower space utilization when assembled. Using pouch cells, which have a thinner profile and higher energy density, as power battery cells presents challenges, including difficulties in heat dissipation design and a lack of pressure relief structures. Especially when pouch batteries are stacked together with their large ends in close contact, a bulging and explosion in one cell will first deform the large end, directly affecting adjacent cells and causing greater danger. This is a technical challenge that urgently needs to be overcome in the development of pouch batteries. Utility Model Content

[0004] The technical problem to be solved by this utility model is that the heat dissipation design of soft-pack battery cells is not easy and lacks a pressure relief structure. These shortcomings will lead to a reduction in the safety performance of power batteries and cause problems such as explosions. In view of the problems existing in the prior art, a soft-pack battery cell with a pressure relief structure is provided.

[0005] The purpose and effects of this utility model are achieved by the following specific technical means:

[0006] A pouch cell with a pressure relief structure includes:

[0007] The housing has grooves on its surface, in which bare battery cells are installed, and several pressure relief structures are provided on the outside of the grooves.

[0008] The housing is divided into two parts along the center line: a load-bearing part and a cover part. A groove is formed in the load-bearing part, and the surface of the load-bearing part and the outer periphery of the groove is an adhesive area. The cover part covers the load-bearing part and is thermoplastically fixed to the adhesive area. An aluminum sheet corresponding to the groove is provided on the surface of the cover part, and the aluminum sheet is in contact with the bare battery cell.

[0009] A further preferred embodiment: the number of grooves is one or two;

[0010] When there are two grooves, they are symmetrically distributed on the surface of the shell, and the shell is folded along the center line. The two grooves are combined to form a cavity.

[0011] A further preferred embodiment: the surface of the adhesive area and the outer periphery of the groove are provided with a rough portion with a width of not less than 0.3 mm, and the surface of the rough portion is provided with a number of pits.

[0012] A further preferred embodiment: the aluminum sheet has a thickness of 10μm-100μm, and the area of ​​the aluminum sheet is less than or equal to the area of ​​the groove.

[0013] A further preferred embodiment: the pressure relief structure includes an explosion-proof zone and a patch;

[0014] The explosion-proof zone is located on the side wall of the groove, and it is a weak point in the shell, with a thickness less than other parts of the shell.

[0015] A further preferred embodiment: the outer surface of the explosion-proof zone is provided with a frosted area, and the frosted area is a rough surface; the patch is fixed to the frosted area and the patch covers the outer surface of the explosion-proof zone.

[0016] A further preferred embodiment: the patch surface is provided with non-penetrating grooves.

[0017] The beneficial effects of this utility model are:

[0018] 1. After the load-bearing part and the cover part are heat-sealed, the aluminum sheet comes into contact with the bare cell. The aluminum sheet plays a heat dissipation role inside the cell. Because the outer layer of the bare cell is a diaphragm, there is plastic contact between the diaphragm and the aluminum-plastic composite film, which cannot effectively conduct heat. However, the metal aluminum sheet comes into contact with the outer surface of the bare cell, separating the large surface of the bare cell from the shell. The aluminum sheet can transfer the heat of the bare cell to the shell, reducing the temperature of the bare cell itself.

[0019] 2. When a battery cell bulges due to excessive internal pressure during use, the explosion-proof zone, being a weak point in the casing, will be the first to be ruptured and depressurized. The explosion-proof zone, acting as a pressure relief mechanism on the side of the pouch cell, prevents bulging or explosion of the two large end faces of the pouch cell after pressure relief. When cells are assembled, the module's safety performance is greatly improved. Depressurization of a single cell does not affect adjacent cells. The patch further blocks the bursting force, preventing excessive impact from damaging the external battery module structure. The patch surface has non-penetrating grooves; when the patch bursts, it will break along these grooves and will not detach from the explosion-proof zone, preventing it from being ejected onto other external structures, such as sensing elements, and interfering with their operation. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic diagram showing the overall structure of this utility model broken down.

[0022] Figure 2 This is a schematic diagram of the overall structure assembly of this utility model;

[0023] Figure 3 This is a partial sectional view of the shell structure of this utility model (location of the explosion-proof zone).

[0024] Figure 4 This is a schematic diagram of a partial structure of the shell of this utility model (location of the explosion-proof zone).

[0025] Figures 1-4 In the middle: shell (1), groove (101), adhesive area (2), aluminum sheet (3), bare cell (4), explosion-proof area (5), frosted area (501), patch (6), and groove (601). Detailed Implementation

[0026] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are merely examples for implementing this utility model. It must be pointed out that the disclosed embodiments do not limit the scope of this utility model. On the contrary, any modifications and refinements made without departing from the scope of this utility model are within the patent protection scope of this utility model.

[0027] Please see Figures 1-2 A pouch cell with a pressure relief structure, comprising:

[0028] The surface of the housing 1 has a groove 101 formed by stamping. The housing 1 is made of aluminum-plastic composite film material, which has deformable characteristics. The aluminum-plastic composite film material for the outer packaging of soft-pack batteries is a conventional technology in this field and will not be described in detail here.

[0029] The housing 1 is divided into two parts along the center line, namely the carrying part and the covering part. The groove 101 is formed in the carrying part, and those skilled in the art can design the number of grooves 101 according to actual use requirements. The number of grooves 101 can be one or two. When there are two grooves 101, the grooves 101 are symmetrically distributed on the surface of the housing 1 along the center line. Then there is one groove 101 in the carrying part and one in the covering part. After the housing 1 is folded along the center line, the two grooves 101 will merge to form a cavity. When it is necessary to carry a large-size bare cell 4, the thickness of the bare cell 4 is relatively thick. Two grooves 101 can be punched out. After the grooves 101 are combined to form the space for encapsulating the battery, the height of the space can meet the size of the bare cell 4. When carrying a small-size bare cell 4, only one groove 101 needs to be punched out. The pit depth of one groove 101 can meet the height requirements of the small-size cell.

[0030] Please see Figures 1-2 The surface of the receiving part and the outer periphery of the groove 101 is the adhesive area 2. After the covering part is folded along the center line of the shell 1, it covers the receiving part and is thermoplastically fixed to the adhesive area 2. The surface of the adhesive area 2 and the outer periphery of the groove 101 is provided with a rough part with a width of not less than 0.3mm, and the surface of the rough part is provided with several pits. The rough part is formed by roughening the aluminum material in the shell 1 during the aluminum-plastic film composite stage. When the receiving part and the covering part are heat-sealed, the highly melted plastic in the covering part can penetrate into the pits through the rough part of the adhesive area 2 to achieve a tighter heat seal and prevent air leakage.

[0031] The surface of the cover is provided with an aluminum sheet 3 corresponding to the groove 101. The thickness of the aluminum sheet 3 is 10μm-100μm, and the area of ​​the aluminum sheet 3 is less than or equal to the area of ​​the groove 101. After the carrier part and the cover part are heat-sealed, the aluminum sheet 3 contacts the bare cell 4. The aluminum sheet 3 plays a heat dissipation role inside the soft-pack cell. Since the outer layer of the bare cell 4 is a separator, the plastic contact between the separator and the aluminum-plastic composite film cannot effectively conduct heat. However, the metal aluminum sheet 3 contacts the outer surface of the bare cell 4, separating the large surface of the bare cell 4 from the shell 1. The aluminum sheet 3 can transfer the heat of the bare cell 4 to the shell 1, thereby reducing the temperature of the bare cell 4.

[0032] Please see Figures 1-4 The outer side of the groove 101 is provided with several pressure relief structures, including an explosion-proof zone 5 and a patch 6. The explosion-proof zone 5 is located on the side wall of the groove 101. The thickness of the explosion-proof zone 5 is preferably two-thirds of the thickness of the shell 1. The explosion-proof zone 5 is formed by hot pressing of the mold. When the internal pressure of the soft-pack battery cell is too high and it bulges during use, the explosion-proof zone 5 will be the first to be broken and depressurized because it is a weak point of the shell 1. The explosion-proof zone 5 is broken by pressure. The explosion-proof zone 5 plays a pressure relief effect on the side of the soft-pack battery cell. After the pressure is relieved by the explosion-proof zone 5, the upper and lower large end faces of the soft-pack battery cell will not bulge or explode. After the battery cells are assembled, the safety performance of the module is greatly improved. The pressure relief of a single battery cell does not affect the adjacent battery cells.

[0033] The outer surface of the explosion-proof zone 5 is provided with a frosted area 501, and the frosted area 501 is a rough surface. The frosted area 501 can be made using the same manufacturing method as the adhesive area 2. The patch 6 is fixed to the frosted area 501 by heat fusion or adhesive. When the pressure breaks through the explosion-proof zone 5, the patch 6 can further block the bursting force, avoiding the impact force from being too strong and damaging the external battery module structure. In addition, the surface of the patch 6 is provided with non-penetrating grooves 601. When the patch 6 bursts, it will break along the grooves 601. The patch 6 will not detach from the explosion-proof zone 5, which can prevent the patch 6 from being pushed out onto other external structures, such as sensing elements, and thus preventing them from interfering with their operation.

Claims

1. A soft-pack battery cell with a pressure relief structure, characterized in that, include: The housing has grooves on its surface, in which bare battery cells are installed, and several pressure relief structures are provided on the outside of the grooves. The housing is divided into two parts along the center line: a load-bearing part and a cover part. A groove is formed in the load-bearing part, and the surface of the load-bearing part and the outer periphery of the groove is an adhesive area. The cover part covers the load-bearing part and is thermoplastically fixed to the adhesive area. An aluminum sheet corresponding to the groove is provided on the surface of the cover part, and the aluminum sheet is in contact with the bare battery cell.

2. The soft-pack battery cell with a pressure relief structure according to claim 1, characterized in that: The number of the grooves is one or two; When there are two grooves, they are symmetrically distributed on the surface of the shell, and the shell is folded along the center line. The two grooves are combined to form a cavity.

3. A soft-pack battery cell with a pressure relief structure according to claim 1, characterized in that: The surface of the adhesive area and the outer periphery of the groove are provided with a rough part with a width of not less than 0.3 mm, and the surface of the rough part is provided with a number of pits.

4. A soft-pack battery cell with a pressure relief structure according to claim 1, characterized in that: The aluminum sheet has a thickness of 10μm-100μm, and the area of ​​the aluminum sheet is less than or equal to the area of ​​the groove.

5. A soft-pack battery cell with a pressure relief structure according to claim 1, characterized in that: The pressure relief structure includes an explosion-proof zone and a patch; The explosion-proof zone is located on the side wall of the groove, and it is a weak point in the shell, with a thickness less than other parts of the shell.

6. A soft-pack battery cell with a pressure relief structure according to claim 5, characterized in that: The outer surface of the explosion-proof zone is provided with a frosted area, which is a rough surface. The patch is fixed to the frosted area and covers the outer surface of the explosion-proof zone.

7. A soft-pack battery cell with a pressure relief structure according to claim 6, characterized in that: The patch surface has non-penetrating grooves.

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