Secondary lithium ion battery

Abstract

The invention discloses a secondary lithium ion battery which comprises a battery shell, a cell held in the battery shell, a battery top cover arranged on the battery shell in a sealing manner, and electrolyte filled in the battery shell, wherein a positive pole and a negative pole are arranged on the battery top cover, and are respectively electrically connected with a positive electrode piece and a negative electrode piece of the cell through connecting members, one or two of the connecting members is or are provided with a protruding part protruding towards the direction of the battery shell on each side, and when the battery shell is squashed by an external force, the protruding parts of the connecting members are in contact with the battery shell to ensure that an external short circuit is realized between the positive electrode and the negative electrode of the secondary lithium ion battery. According to the secondary lithium ion battery, the protruding parts are arranged on the connecting members for connecting the poles with the positive electrode piece and the negative electrode pieces, and the external short circuit is realized by using original connecting members when the secondary lithium ion battery is squashed, and the energy density of the secondary lithium ion battery can be not influenced when the safety of the secondary lithium ion battery is improved.

Description

technical field [0001] The invention relates to a lithium ion secondary battery, in particular to a lithium ion secondary battery with high safety and energy density. Background technique [0002] Lithium-ion secondary batteries have begun to be used to power electric vehicles such as electric vehicles due to their high energy, high capacity, and high power. This requires that while improving the electrochemical performance of lithium-ion secondary batteries, the safety of lithium-ion secondary batteries as power sources in electric vehicles must also be strictly guaranteed. In order to meet the requirements of safety performance in actual use, lithium-ion secondary batteries should be able to pass the abuse safety test under harsh conditions, and the three extreme safety tests usually carried out are nail penetration, crushing and overcharging. [0003] During the crush test of the lithium-ion secondary battery, the positive and negative electrodes in a local area will be ...

AI Technical Summary

Problems solved by technology

[0006] However, the above-mentioned design has many defects in actual use, especially the need to add a conductive plate that does not usually work in the battery case, which will occupy the precious space inside the battery, resulting in a decrease in the energy density and power density of the battery

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