Secondary cell top cover and secondary cell

Abstract

The invention relates to the field of energy storage devices, in particular to a secondary cell top cover and a secondary cell.The secondary cell top cover comprises a top cover sheet, a first post terminal unit, a second post terminal unit, an overturning sheet and a conducting sheet.The first post terminal unit is fixedly and electrically connected with the top cover sheet.The second post terminal unit comprises a second post terminal and a cover plate, the cover plate is fixedly and electrically connected with the second post terminal, and both the cover plate and the second post terminal are connected with the top cover sheet in an insulating mode.The overturning sheet is electrically connected with the top cover sheet and arranged below the cover plate.The conducting sheet is electrically connected with the top cover sheet and arranged above the overturning sheet.In a normal state, both the overturning sheet and the conducting sheet are disconnected from the cover plate; when air pressure in the cell reaches a set value, the overturning sheet turns over so that both the overturning sheet and the conducting sheet can be electrically connected with the cover plate.The secondary cell comprises the secondary cell cover.According to the secondary cell top cover and the secondary cell, the risk that the overturning sheet is topped or fused is effectively reduced.

Description

technical field [0001] The present application relates to the field of energy storage devices, in particular to a secondary battery top cover and a secondary battery. Background technique [0002] Lithium-ion batteries have been used in hybrid and electric vehicles due to their high energy, high capacity, and high power. For lithium-ion batteries used as automotive power supplies, their safety is the top priority. Overcharge tests and nail penetration tests are one of the most extreme safety tests for lithium-ion batteries. [0003] Due to the high energy and high activity of lithium-ion batteries, a large amount of gas will be generated during the overcharge test and the nail penetration test, and the internal heat will be generated sharply. In severe cases, a fire and explosion will occur. At present, most of the overcharge tests of lithium-ion batteries use the principle of external short circuit to short-circuit the battery cell before the battery goes out of control, s...

AI Technical Summary

Problems solved by technology

[0005] However, in order to ensure that the flipping sheet is relatively easy to flip, at least the flipping portion of the flipping sheet needs to be set thinner.

When the flipper flips over to cause an external short circuit between the positive pole unit and the negative pole unit, if the short-circuit current is too large at this time, it often causes the flipper to be cut off instantly or blown (for example, when there are many batteries and overcharged, each battery Gas will be produced inside the core. At this time, due to the difference in gas production, the flipping pieces of each cell cannot be flipped at the same time, which causes the first flipped cell to have a larger circuit current)

At present, the flow capacity of the flip sheet is often improved by thickening the flip sheet. However, as the thickness increases, the flip pressure required for the flip sheet increases sharply, which increases the safety hazard of the battery.

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