Battery top cover with double-layer anti-explosion valve

Abstract

The utility model provides a battery top cover with a double-layer explosion-proof valve, and relates to the technical field of batteries, the bottom of the top cover is provided with lower plastic, the top surface of the top cover is provided with a through-hole-shaped explosion-proof hole, the explosion-proof hole is internally provided with an explosion-proof structure and a protection sheet covering the explosion-proof structure, the explosion-proof structure is composed of two layers of explosion-proof sheets, and the two layers of explosion-proof sheets are arranged on the top surface of the top cover. A plurality of pressure relief through holes are formed in the positions, corresponding to the explosion-proof holes, in the lower plastic, the poles are installed on the two sides of the top cover and are the positive pole and the negative pole respectively, the bottoms of the poles penetrate through the lower plastic, pressure relief can be conducted in an aluminum-plastic film tearing mode firstly and then conducted through nicking and cracking through the double-layer explosion-proof piece and the weak area, and compared with a traditional single aluminum explosion-proof valve, pressure relief is more stable, and the service life of the explosion-proof valve is prolonged. Pressure is relieved through the transition groove, and the pressure relief stability can be further improved through the nicks evenly distributed in a circular surrounding mode.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a battery top cover with a double-layer explosion-proof valve. Background Technology

[0002] Lithium-ion batteries are classified by shape into square lithium batteries, cylindrical lithium batteries, and button lithium batteries; and by outer casing material into aluminum-cased lithium batteries, steel-cased lithium-ion batteries, and pouch lithium batteries.

[0003] Aluminum-cased lithium batteries consist of a casing, a cover, and battery cells. The battery cells are housed inside the casing, which has an opening at the top. The cover seals this opening, and terminals formed on the cover allow for electrical connection between the lithium battery and external electronic components, providing power. During use, lithium batteries can experience explosions due to factors such as charger malfunctions and overcharging, which can lead to abnormal gas production caused by internal chemical reactions. This excessive internal pressure can result in a battery explosion. However, existing battery covers incorporate explosion-proof valve structures, using thin aluminum sheets as the valve. When pressure becomes excessive, the aluminum sheet is breached first, allowing the internal pressure of the battery cell to escape.

[0004] Currently, some explosion-proof valves on the top covers of prismatic batteries use scoring to design the explosion path. For example, patent publication number CN108428836A describes an explosion-proof valve for a secondary battery top cover, a top cover assembly, a secondary battery, and a car. When the battery depressurizes, it will push open the explosion-proof valve along the horizontal and vertical scoring and branch scoring. However, this design reduces the pressure threshold that the explosion-proof valve can withstand, causing the valve body to crack before the gas pressure inside the battery cell reaches the pressure relief threshold. The explosion pressure is not stable enough. How to design a top cover explosion-proof valve that can alleviate the pressure relief while maintaining stability is an urgent technical problem. Utility Model Content

[0005] The technical problem to be solved by this utility model is that the burst pressure of the explosion-proof valve with grooves is not stable enough. In view of the problems existing in the prior art, a battery top cover with a double-layer explosion-proof valve is provided.

[0006] The purpose and effects of this utility model are achieved by the following specific technical means:

[0007] A battery top cover with a double-layer explosion-proof valve includes:

[0008] Top cover, with a lower plastic part installed at the bottom of the top cover;

[0009] The top surface of the top cover has a through-hole-shaped explosion-proof hole, and an explosion-proof structure and a protective plate covering the explosion-proof structure are installed in the explosion-proof hole. The explosion-proof structure consists of two layers of explosion-proof plates.

[0010] Several pressure relief holes are provided in the lower plastic part at the positions corresponding to the explosion-proof holes;

[0011] This design, through two layers of explosion-proof sheets, can improve the stability of the battery during the depressurization process.

[0012] A further preferred embodiment: The top cover has poles installed on both sides, which are positive and negative poles respectively, and the bottom of the poles passes through the lower plastic.

[0013] This design allows the positive and negative terminals to be electrically connected to the bare battery cell tabs inside the aluminum casing.

[0014] A further preferred embodiment: the top surface of the top cover has a through-hole-shaped injection hole, and the bottom plastic top surface has a through-hole-shaped interface corresponding to the injection hole.

[0015] A further preferred embodiment: one end of the explosion-proof hole is provided with a step section 1 and a step section 2 that sink twice in succession, and the outer diameter of step section 1 is larger than the outer diameter of step section 2, and the protective plate is provided on step section 1.

[0016] A further preferred embodiment: The other end of the explosion-proof hole is provided with a stepped section three, and the two layers of explosion-proof sheets are respectively disposed in the stepped section two and the stepped section three. With this design, the two layers of explosion-proof sheets are arranged vertically from top to bottom, which can achieve the effect of double-layer explosion-proof pressure relief.

[0017] A further preferred embodiment: both the top cover and the explosion-proof sheet are made of aluminum, and the outer edge of the explosion-proof sheet is fixedly connected to the explosion-proof hole by welding or riveting;

[0018] With this design, the top cover and the explosion-proof sheet are made of the same material, ensuring the connection between the two. When a high-strength connection is required, welding is the preferred method for connection.

[0019] A further preferred embodiment: a transition groove is provided between the opposing surfaces of the two layers of explosion-proof sheets, and the height of the transition groove is 0.001mm-3mm. With this design, after the pressure is released and the first layer of explosion-proof sheet is broken, the transition groove can be used to reduce the impact force of the explosion.

[0020] A further preferred embodiment: the explosion-proof sheet is circular, and a circular weak zone is provided at the center of the explosion-proof sheet.

[0021] A further preferred embodiment: the weak area is made of aluminum-plastic film composite material, and the outer edge of the weak area is connected to the explosion-proof sheet by stamping or adhesive, and the cross-sectional width of the connection is ≥0.1mm.

[0022] A further preferred embodiment: the surface of the explosion-proof sheet is provided with several grooves surrounding the weak area, and the grooves are straight lines, curves or Z-shaped lines.

[0023] The beneficial effects of this utility model are:

[0024] 1. When the aluminum casing is depressurized, the weak area near the battery cell is first punctured. The weak area will bulge and deform slightly under impact and burst open, releasing gas into the transition groove. The transition groove can reduce the impact force of the pressure. Then, the pressure is released through the second weak area. The aluminum-plastic film depressurization is safer than the aluminum explosion-proof sheet. The explosion-proof sheet has the risk of being punched out and cutting other parts of the external battery module. The aluminum-plastic film bursts and tears, which will not affect external parts.

[0025] After the aluminum-plastic film bears the first pressure, the explosion-proof sheet bears the second pressure. If the pressure relief continues to increase, the grooves on the surface of the explosion-proof sheet will crack. The grooves guide the path of the explosion-proof sheet to burst. Several grooves are set around the weak area. The grooves are straight lines, curves or Z-shaped lines. The explosion-proof sheet is circular, and the grooves are evenly distributed in a circular ring. The stress is also more even, and the stability is stronger than that of the traditional elliptical shape.

[0026] With its double-layered explosion-proof sheet and weak area, the valve can first release pressure by tearing the aluminum-plastic film, and then release pressure by scoring and cracking. Compared with the traditional single aluminum explosion-proof valve, the pressure release is more stable. The transition groove reduces the pressure, and the evenly distributed circular scoring further improves the stability of pressure release. Attached Figure Description

[0027] The present invention will be further described below with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the overall structure assembly of this utility model;

[0029] Figure 2 This is a schematic diagram showing the overall structure of this utility model broken down.

[0030] Figure 3 This is a partial front view of the top cover structure of this utility model (location of the explosion-proof hole);

[0031] Figure 4 This is a partial front view of the top cover structure of this utility model (location of the explosion-proof hole);

[0032] Figure 5 This utility model Figure 4 A magnified schematic diagram of the structure at point A in the diagram;

[0033] Figure 6 This is a schematic diagram showing the disassembled structure of the explosion-proof sheet and the protective sheet of this utility model;

[0034] Figure 7 This is a schematic diagram of the explosion-proof sheet structure of this utility model;

[0035] Figure 8 This is a schematic diagram of the explosion-proof sheet structure of this utility model.

[0036] Figures 1-8Middle: Top cover (1), lower plastic (2), pole (3), injection hole (4), explosion-proof hole (5), explosion-proof sheet (6), scoring (601), weak area (7), protective sheet (8). Detailed Implementation

[0037] To better understand the above-mentioned objectives, features, and advantages of this utility model, the following description is provided in conjunction with the accompanying drawings. Figures 1-8 The present invention will be further described in detail below with specific embodiments. The following embodiments are merely examples of implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. On the contrary, any modifications and refinements made without departing from the scope of the present invention are within the patent protection scope of the present invention.

[0038] Please see Figures 1-2 A battery top cover with a double-layer explosion-proof valve includes:

[0039] The top cover 1 has a lower plastic 2 installed at its bottom. The lower plastic 2 is connected to the top cover 1 by a snap fastener. The top cover 1 has poles 3 installed on both sides, which are the positive and negative poles respectively. The bottom of the poles 3 passes through the lower plastic 2. After the top cover 1 is assembled into the aluminum shell, the tabs of the bare battery cell will face the poles 3. A metal connecting piece is welded to the top of the tab, and then the poles 3 are welded to the metal connecting piece. The positive poles 3 and the negative poles 3 can then be electrically connected to the tabs of the bare battery cell.

[0040] The top surface of the top cover 1 has a through-hole-shaped injection hole 4, and the top surface of the lower plastic 2 has a through-hole-shaped interface corresponding to the injection hole 4. Liquid can be injected through the injection hole 4. After the injection is completed, the sealing plug is inserted into the injection hole 4, and the aluminum shell battery cell can be charged and discharged to form.

[0041] Please see Figures 2-8 The top surface of the top cover 1 has a through-hole-shaped explosion-proof hole 5, and an explosion-proof structure and a protective plate 8 covering the explosion-proof structure are installed in the explosion-proof hole 5. The explosion-proof structure consists of two layers of explosion-proof plates 6. One end of the explosion-proof hole 5 is provided with a stepped section 1 and a stepped section 2 that sink twice in succession (e.g., Figure 4 As shown), the other end of the explosion-proof hole 5 is provided with a stepped section three. The two layers of explosion-proof sheets 6 are respectively provided in the stepped section two and the stepped section three. The outer diameters of the stepped section two and the stepped section three are preferably equal. The top cover 1 and the explosion-proof sheet 6 are both made of aluminum. The outer edge of the explosion-proof sheet 6 is fixedly connected to the explosion-proof hole 5 by welding or riveting. The connection strength between the top cover 1 and the explosion-proof sheet 6 of the same material is higher. When the top cover 1 and the explosion-proof sheet 6 are riveted, the riveting depth is preferably more than 0.5mm to prevent the explosion-proof sheet 6 from being easily broken.

[0042] Furthermore, the explosion-proof sheet 6 has a circular weak zone 7 at its center. The weak zone 7 is made of aluminum-plastic composite material, and its outer edge is connected to the explosion-proof sheet 6 by stamping or adhesive. The width of the connection section D1 is ≥0.1mm (e.g., Figure 5 (As shown), to prevent the weak area 7 from being too small and easily detaching from the explosion-proof sheet 6;

[0043] Because the aluminum-plastic film is an aluminum-plastic composite material, its strength is lower than that of the explosion-proof sheet 6. When the aluminum shell is depressurized, it first breaks through the weak area 7 near the battery cell. The weak area 7 will bulge and deform slightly under impact and burst open, releasing gas into the transition groove. A transition groove is provided between the opposite surfaces of the two explosion-proof sheets 6 (e.g., Figure 5 As shown), the height of the transition groove D2 is 0.001mm-3mm, and the preferred height of the transition groove is 1mm. After the pressure passes through the first weak zone 7, it is released into the transition groove, which can reduce the impact of the pressure. Then, it is released through the second weak zone 7. The pressure release of the aluminum-plastic film is safer than that of the aluminum explosion-proof sheet 6. The explosion-proof sheet 6 has the risk of being blown out and cutting other parts of the external battery module. The aluminum-plastic film bursts and tears, which will not affect the external parts.

[0044] After the aluminum-plastic film bears the first pressure, the explosion-proof sheet 6 bears the second pressure. If the pressure relief continues to increase, the grooves 601 on the surface of the explosion-proof sheet 6 will crack. The path of the explosion-proof sheet 6 bursting is guided by the grooves 601. Several grooves 601 are set around the weak area 7. The grooves 601 are straight lines, curves or Z-shaped lines. The explosion-proof sheet 6 is circular. The grooves 601 are evenly distributed in a circular ring. The stress is also more even. It is more stable than the traditional elliptical shape.

[0045] With the double-layered explosion-proof sheet 6 and the weak area 7, pressure can be released first by tearing the aluminum-plastic film, and then by cracking the groove 601 to release pressure. Compared with the traditional single aluminum explosion-proof valve, the pressure release is more stable. The pressure is reduced by the transition groove, and the groove 601, which is evenly distributed in a circular pattern, can further improve the pressure release stability.

[0046] The outer diameter of step one is larger than the outer diameter of step two. The protective plate 8 is set on step one. The area of ​​the protective plate 8 is larger than that of the explosion-proof plate 6. The protective plate 8 is made of plastic film material and is preferably attached to one part of the step. When pressure is applied to the protective plate 8, the protective plate 8 will separate from the top cover 1, thus playing the role of a third pressure resistance.

[0047] Several pressure relief holes are provided in the lower plastic 2 at the position corresponding to the explosion-proof hole 5. When the battery is depressurized, the pressure is first released through the pressure relief holes. The pressure relief impact can be reduced by multiple pressure relief holes.

Claims

1. A battery top cover with a double-layer explosion-proof valve, characterized in that, include: Top cover, with a lower plastic part installed at the bottom of the top cover; The top surface of the top cover has a through-hole-shaped explosion-proof hole, and an explosion-proof structure and a protective plate covering the explosion-proof structure are installed in the explosion-proof hole. The explosion-proof structure consists of two layers of explosion-proof plates. Several pressure relief holes are provided in the lower plastic part at the positions corresponding to the explosion-proof holes.

2. The battery top cover with a double-layer explosion-proof valve according to claim 1, characterized in that: The top cover has poles installed on both sides, which are positive and negative poles respectively, and the bottom of the poles passes through the lower plastic.

3. A battery top cover with a double-layer explosion-proof valve according to claim 1, characterized in that: The top surface of the top cover has a through-hole-shaped injection hole, and the bottom plastic top surface has a through-hole-shaped connector at the position corresponding to the injection hole.

4. A battery top cover with a double-layer explosion-proof valve according to claim 1, characterized in that: The explosion-proof hole has a stepped section 1 and a stepped section 2 that sink twice in succession, and the outer diameter of the stepped section 1 is larger than the outer diameter of the stepped section 2. The protective plate is set on the stepped section 1.

5. A battery top cover with a double-layer explosion-proof valve according to claim 4, characterized in that: The other end of the explosion-proof hole is provided with a stepped section three, and the two layers of explosion-proof sheets are respectively disposed in the stepped section two and the stepped section three.

6. A battery top cover with a double-layer explosion-proof valve according to claim 5, characterized in that: Both the top cover and the explosion-proof sheet are made of aluminum, and the outer edge of the explosion-proof sheet is fixedly connected to the explosion-proof hole by welding or riveting.

7. A battery top cover with a double-layer explosion-proof valve according to claim 6, characterized in that: A transition groove is provided between the opposing surfaces of the two explosion-proof sheets, and the height of the transition groove is 0.001mm-3mm.

8. A battery top cover with a double-layer explosion-proof valve according to claim 1, characterized in that: The explosion-proof sheet is circular, and a circular weak area is provided in the center of the explosion-proof sheet.

9. A battery top cover with a double-layer explosion-proof valve according to claim 8, characterized in that: The weak area is made of aluminum-plastic film composite material, and the outer edge of the weak area is connected to the explosion-proof sheet by stamping or adhesive, and the cross-sectional width of the connection is ≥0.1mm.

10. A battery top cover with a double-layer explosion-proof valve according to claim 1, characterized in that: The surface of the explosion-proof sheet has several grooves arranged around the weak area, and the grooves are straight lines, curves or Z-shaped lines.

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