Lower plastic of secondary battery

Abstract

The utility model provides secondary battery lower plastic which comprises a lower plastic body, a second boss is arranged in the middle of the bottom surface of the lower plastic body, an exhaust grating is arranged on the second boss, a first groove is formed in the upper surface of the lower plastic body, a second groove is formed in the first groove, and the exhaust grating is arranged in the second groove. A through liquid injection hole is formed in the bottom face of the second groove, an air guide groove communicated with the first groove and the exhaust grid is formed in the upper surface of the lower plastic body, and a plurality of through liquid guide grooves are formed in the side wall of the second groove. According to the explosion-proof valve, the exhaust grating on the boss II is communicated with the liquid guide groove through the gas guide groove, when the explosion-proof valve is opened due to thermal runaway, gas and heat generated by thermal runaway of the battery can be subjected to gas pressure and heat diffusion through the exhaust grating and the liquid guide groove, and the explosion-proof valve has multiple pressure relief paths and can be used for guiding out or discharging the gas in time; and the problem of thermal runaway of the battery after valve opening is effectively solved.

Description

Technical Field

[0001] The utility model relates to the field of lithium ion batteries, in particular to a lower plastic of a secondary battery. Background Art

[0002] In the prior art, the insulating parts installed under the battery top cover sheet are generally collectively referred to as lower plastics. The lower plastics are arranged between the top cover sheet and the bare battery cell to prevent short circuit between the bare battery cell and the top cover sheet.

[0003] The lower plastics are generally assembled at the bottom of the top cover sheet by interference fit. In order to increase the capacity of the battery cell, the distance between the lower plastics and the battery cell is getting closer and closer. When the explosion-proof valve opens due to thermal runaway, most of the gas and heat generated by the thermal runaway of the battery can only diffuse through the air pressure and heat at the connecting part of the lower plastics at the explosion-proof valve. Generally, the drainage convex part of the lower plastics at the explosion-proof valve is blocked by the bare battery cell, so the pressure cannot be relieved in time and the heat cannot be taken away. If the gas cannot be exported or drained in time, it may cause the battery to explode.

[0004] Therefore, we propose a lower plastic of a secondary battery to solve the problem that the explosion-proof valve hole of the lower plastic is prone to untimely exhaust and pressure relief. Content of the Utility Model

[0005] The purpose of the utility model is to solve the defects existing in the prior art. To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A lower plastic of a secondary battery, including a lower plastic body. A second convex platform is arranged in the middle of the bottom surface of the lower plastic body. An exhaust grille is arranged on the second convex platform. A first groove is opened on the upper surface of the lower plastic body. A second groove is opened in the first groove. A through liquid injection hole is opened at the bottom surface of the second groove. A gas guide groove communicating the first groove and the exhaust grille is opened on the upper surface of the lower plastic body. Several through liquid guide grooves are opened on the side wall of the second groove.

[0007] Further preferably, the liquid guide groove is any one of U-shaped, rectangular and V-shaped.

[0008] Further preferably, the number of the liquid guide grooves is 3-6, and they are evenly distributed on the side wall of the second groove. Preferably, the number of the liquid guide grooves is 4.

[0009] Further preferably, pole installation holes are opened on the surface of the lower plastic body. There are two pole installation holes, which are distributed on both sides of the lower plastic body.

[0010] Further preferably, a plurality of positioning columns are arranged on the surface of the lower plastic body, and the positioning columns are close to the edge of the lower plastic body.

[0011] Further preferably, first bosses and third bosses are respectively arranged on two sides of the lower plastic body. Square grooves are formed on the surfaces of the first bosses and the third bosses, and through holes are formed in the square grooves.

[0012] Compared with the prior art, the beneficial effects of the present utility model are as follows: The exhaust grille on the second boss of the present utility model is communicated with the liquid guide groove through the gas guide groove. When the explosion-proof valve opens due to thermal runaway, the gas and heat generated by the thermal runaway of the battery can be subjected to air pressure and heat diffusion through the exhaust grille and the liquid guide groove. It has multiple pressure relief paths, can export or discharge the gas in time, and effectively solves the problem that the battery still has thermal runaway after the valve opens. Description of the Drawings

[0013] Figure 1 is a structural schematic diagram of the present utility model;

[0014] Figure 2 is a top view of the present utility model;

[0015] Figure 3 is a front view of the present utility model.

[0016] In the figure: lower plastic body 1, first boss 2, second boss 3, third boss 4, first groove 5, second groove 6, liquid guide groove 7, liquid injection hole 8, gas guide groove 9, through hole 21, pole mounting hole 11, positioning post 12, exhaust grille 31. Specific Embodiments

[0017] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0018] Referring to Figures 1 - 3 , a lower plastic for a secondary battery includes a lower plastic body 1. A second boss 3 is arranged in the middle of the bottom surface of the lower plastic body 1. An exhaust grille 31 is arranged on the second boss 3. A first groove 5 is formed on the upper surface of the lower plastic body 1. A second groove 6 is formed in the first groove 5. A through liquid injection hole 8 is opened at the bottom surface of the second groove 6. A gas guide groove 9 communicating the first groove 5 and the exhaust grille 31 is formed on the upper surface of the lower plastic body 1. Several through liquid guide grooves 7 are formed on the side wall of the second groove 6.

[0019] In the embodiment: When the explosion-proof valve opens due to thermal runaway, the gas and heat generated by the thermal runaway of the battery are subjected to air pressure and heat diffusion from the explosion-proof valve through the exhaust grille 31 on the lower plastic.

[0020] In the embodiment: The exhaust grille 31 on the second boss 3 is communicated with the liquid guide groove 7 through the gas guide groove 9. When the explosion-proof valve opens due to thermal runaway, part of the gas and heat generated by the thermal runaway of the battery are diffused in terms of air pressure and heat from the explosion-proof valve through the liquid guide groove 7 and the gas guide groove 9.

[0021] In the embodiment: The depth of the gas guide groove 9 is the same as that of the first groove 5, that is, the bottom surface of the gas guide groove 9 and the first groove 5 is on the same horizontal plane. In addition, the depth of the gas guide groove 9 and the first groove 5 may not be the same. The depth of the gas guide groove 9 may be greater than that of the first groove 5 or less than that of the first groove 5. The depth of the gas guide groove 9 is any value within 0.1 - 1 mm. For example, it can be 0.1 mm, 0.3, 0.5, 0.7 mm, 0.9 or 1.0 mm; the depth of the first groove 5 is any value within 0.1 - 1 mm. For example, it can be 0.1 mm, 0.3, 0.5, 0.7 mm, 0.9 or 1.0 mm.

[0022] In another embodiment: The bottom surface of the gas guide groove 9 can be an inclined surface.

[0023] The liquid guide groove 7 is any one of U-shaped, rectangular, and V-shaped. The number of the liquid guide grooves 7 is 3 - 6 and they are evenly distributed on the side wall of the second groove 6.

[0024] In the embodiment: The liquid guide groove 7 is in any shape capable of conducting gas and liquid. The liquid guide groove 7 penetrates through the lower plastic body 1. It can not only guide the gas and heat generated by the thermal runaway of the battery to the explosion-proof valve, but also the electrolyte can be injected into the battery cell through the liquid guide groove 7 during liquid injection, which is beneficial to improving the liquid injection efficiency.

[0025] Pole post mounting holes 11 are formed on the surface of the lower plastic body 1. There are two pole post mounting holes 11 and they are distributed on both sides of the lower plastic body 1.

[0026] In the embodiment: One is the positive pole post mounting hole and the other is the negative pole post mounting hole.

[0027] A number of positioning posts 12 are arranged on the surface of the lower plastic body 1, and the positioning posts 12 are close to the edge of the lower plastic body 1.

[0028] In the embodiment: The positioning post 12 is of a T-shaped structure and is positioned and clamped with the top cover sheet through the positioning post 12.

[0029] First bosses 2 and third bosses 4 are respectively arranged on both sides of the lower plastic body 1. Square grooves are formed on the surfaces of the first bosses 2 and third bosses 4, and through holes 21 are formed through the square grooves.

[0030] In the embodiment: By abutting the bottoms of the first boss 2 and the third boss 4 against the bare battery cell, the square grooves are evenly distributed on both sides of the lower plastic body 1. When gas or liquid enters between the lower plastic body 1 and the top cover sheet, through the cooperation of the square grooves and the internal through holes 21 therein, the function of exhausting gas and liquid inside the battery is realized.

[0031] The material of the lower plastic body 1 is plastic, for example, it can be polycarbonate, ABS plastic, polypropylene, nylon, etc. The present application does not limit the material of the lower plastic body 1.

[0032] The exhaust grille 31 on the second boss 3 of the present utility model is communicated with the liquid guide groove 7 through the gas guide groove 9. When the explosion-proof valve opens due to thermal runaway, the gas and heat generated by the thermal runaway of the battery can be subjected to air pressure and heat diffusion through the exhaust grille 31 and the liquid guide groove 7. It has multiple pressure relief paths and can timely export or discharge the gas, effectively solving the problem that the battery still has thermal runaway even after the valve opens.

Claims

1. A secondary battery bottom plastic, characterized in that: The utility model comprises a lower plastic body, wherein a boss 2 is arranged in the middle of the bottom surface of the lower plastic body, an exhaust grille is arranged on the boss 2, a groove 1 is arranged on the upper surface of the lower plastic body, a groove 2 is arranged in the groove 1, a through liquid injection hole is arranged on the bottom surface of the groove 2, an air guide groove connecting the groove 1 and the exhaust grille is arranged on the upper surface of the lower plastic body, and a plurality of through liquid guide grooves are arranged on the side wall of the groove 2.

2. The secondary battery lower plastic according to claim 1, characterized in that: The liquid guiding groove is any one of U-shaped, rectangular and V-shaped.

3. The secondary battery lower plastic according to claim 1, characterized in that: The number of the liquid guiding grooves is 3-6, which are evenly distributed on the side wall of the second groove.

4. The secondary battery lower plastic according to claim 1, characterized in that: The surface of the lower plastic body is provided with pole mounting holes, and there are two pole mounting holes distributed on both sides of the lower plastic body.

5. The secondary battery lower plastic according to claim 1, characterized in that: A plurality of positioning columns are arranged on the surface of the lower plastic body, and the positioning columns are close to the edge of the lower plastic body.

6. The secondary battery lower plastic according to claim 1, characterized in that: Boss one and boss three are respectively arranged on both sides of the lower plastic body, and square grooves are opened on the surfaces of boss one and boss three, and through holes are opened in the square grooves.

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