Square lithium ion battery pole anti-rotation structure and manufacturing method thereof

Abstract

The present invention discloses a square lithium ion battery pole anti-rotation structure which comprises a pole (1), an anti-rotation bracket (6), a lower insulation seal washer (7), an upper insulation seal washer (4), a metal seal washer (3) and a nut (2). The pole (1) is composed of two parts of a fastening bolt (9) and a self-locking table (10), wherein the cross section of self-locking table is non-circular. The inner part of anti-rotation bracket is provided with two metal mold inserts (5). A pole hole (11) which has a shape matched with the cross section of self-locking table (10) is provided on the metal mold inserts (5). The invention also discloses a method for manufacturing the structure. The anti-rotation structure of the invention can leave out the inner insulating film of battery cover plate. The anti-rotation strength requirement can be satisfied. The assembling is easy and the bulk production of battery is facilitated.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to an anti-rotation structure for a pole of a square-shaped lithium-ion battery. Background technique [0002] With the application of capacity-type and power-type lithium-ion batteries, the lead-out tabs of the square shell can no longer meet the needs of high-current discharge of lithium-ion batteries, and the pole-type design has begun to replace the tab-lead-out design. During the manufacture and use of the pole-type lithium-ion battery, due to the repeated screwing of the nut, it is easy to cause the plate column to loosen and affect the sealing effect of the battery. In severe cases, it will cause the tabs on the pole piece and the plate to break, shortening the battery life. Or a short circuit inside the battery. The existing methods for preventing the rotation of the pole include: ① casting the pole and the cover as one, and insulating casting between the po...

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Problems solved by technology

However, there are a lot of problems in the above four methods: the first one, because it is one-time casting, the cost is too high, and no such structure is found in domestic lithium-ion batteries for civilian use; the second one, because the anti-rotation part and the cover plate need to be Welding together, the assembly is difficult, the sealing effect of the battery pole will not be very good, the anti-rotation part needs to be matched with the inner platform of the pole, and the anti-rotation part needs to be made into a funnel shape, the anti-rotation part or the pole is difficult to process, domestic This structure has not been found in civilian products produced, and the cost is relatively high; the third type, because the cover plate needs to be concave, and an insulating pad must be added between the cover plate and the pole, in order to achieve sealing and anti-rotation, the cover plate must be thickened , the insulating pad material must have high fatigue resistance, and can achieve good results under the premise of increasing cost and quality. However, the domestic products of this design have thin cover plates and insulating pads. Due to the use of small batteries, it is required The rotational moment of the battery is relatively small, and this design is mostly used for small batteries. Because the large battery requires a large rotational moment when used, this design cannot achieve the desired effect; the fourth type, due to the strength of the plastic parts, the plastic The mass of the parts is relatively large, and the effective thickness of the pole self-locking table needs to be thickened, resulting in an increase in the mass of the pole and a decrease in the utilization rate of the battery cavity. Some domestic manufacturers are using this design, but the effect is not very unsatisfactory.

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