secondary battery

Abstract

A secondary battery, comprising: an electrode assembly (31), a first terminal (11), a second terminal (21) and a top cover sheet (41), the electrode assembly (31) includes a first pole piece, a second A pole piece and a separator arranged between the first pole piece and the second pole piece, the first terminal (11) is electrically connected to the first pole piece, and the second terminal (21) Electrically connected to the second pole piece, at least one of the first terminal (11) and the second terminal (21) is insulated from the top cover piece (41); the secondary battery further includes: The contact piece (12) attached to the first terminal (11), and the conductive piece (22) electrically connected to the second terminal (21), when the internal pressure of the secondary battery exceeds the reference pressure , the contact piece (12) acts under the action of internal pressure and contacts with the conductive piece (22) to form a (12), the electrical connection path of the conductive sheet (22), the second terminal (21) and the second pole piece. This solution improves the safety of the secondary battery.

Description

technical field [0001] The present application relates to the technical field of energy storage devices, in particular to a secondary battery. Background technique [0002] Secondary batteries can be repeatedly charged and discharged, and are widely used in small portable electronic devices such as mobile phones and notebooks, as well as vehicles such as hybrid electric vehicles and pure electric vehicles. During the fast charging or high-power discharging process of the secondary battery, excessive heat will be generated inside, and the electrolyte may decompose. This heat generation and the decomposition of the electrolyte will increase the pressure inside the secondary battery, which may cause The secondary battery catches fire and explodes, reducing the safety of the secondary battery. [0003] In the related art, a contact sheet is usually provided in the secondary battery, and the contact sheet is attached to the top cover sheet. When the pressure inside the secondary...

AI Technical Summary

Problems solved by technology

During the fast charging or high-power discharging process of the secondary battery, excessive heat will be generated inside, and the electrolyte may decompose. This heat generation and the decomposition of the electrolyte will increase the pressure inside the secondary battery, which may cause The secondary battery catches fire and explodes, reducing the safety of the secondary battery

[0004] However, in the above technical solution, the contact sheet is directly arranged on the top cover sheet. Since the top cover sheet is affected by many external factors, for example, the cell will inevitably expand during use, and the top cover sheet is closed by welding. Shell, the outward expansion of the shell will generate tensile stress on the top cover sheet at the same time, or welding tensile stress will be generated on the top cover sheet when the top cover sheet is welded to the shell, etc. Since the contact sheet is directly arranged on the top cover sheet, Therefore, the contact piece will also produce tensile stress

The contact piece is in the state of tensile stress for a long time, which will cause stress fatigue to the contact piece and shorten the service life of the contact piece; at the same time, due to the existence of tensile stress, the sensitivity of the contact piece will decrease, and the contact piece cannot operate under the rated pressure, so that the secondary The safety performance of the battery is reduced

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