High-power flexible packaged lithium ion battery and processing process thereof

Abstract

The invention relates to a high-power flexible packaged lithium ion battery and a processing process thereof. An individual battery cell comprises a negative plate, a positive plate, a first membrane and a second membrane, wherein the first membrane, the negative plate, the second membrane and the positive plate are stacked in sequence; the positive plate is arranged in an innermost layer and formed by winding. According to the lithium ion battery, a first positive island region and a second positive island region which are not coated with active substances are arranged in a certain distance on the two sides of a positive tab; during winding, the second positive island region and the first positive island region are used for correspondingly wrapping a negative tab and the rear surface of the negative tab respectively, so that the lithium separation when the positive active substances are over against the negative tab is avoided. According to the preparation method, the battery is hotly and coldly pressed before formation, and excess electrolyte in the battery is squeezed into an airbag, so that the hardness of the battery is improved, the layers of membranes, the positive plate and the negative plate are in relatively close contact with each other, the interface impedance and the internal resistance of the battery are reduced, and the power energy density of the lithium ion battery is increased.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and relates to a lithium-ion battery and a manufacturing process thereof, in particular to a high-power soft-pack lithium-ion battery and a manufacturing process thereof. Background technique [0002] In order to meet the market's requirements for large-capacity power flexible packaging lithium-ion batteries, it is necessary to increase the length of the pole piece under the condition of strictly controlling the surface density of the pole piece. However, for power lithium-ion batteries using winding technology, too long pole pieces will bring unnecessary troubles to the production process, resulting in an increase in product defect rate, and the internal resistance of batteries with long pole pieces is large, which is not conducive to power batteries The high current charging and discharging seriously hinders the improvement of its power energy density. [0003] In the Chinese patent docume...

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Problems solved by technology

In these two patents, a certain distance from the right end of the positive electrode lug and a certain distance from the left end of the opposite side of the positive electrode lug welding position do not set a blank foil area without coating active materials, which is collectively referred to as "island area" in the industry to avoid negative electrode lugs. When winding, it faces the positive electrode material area. Such a pole piece structure will lead to a series of thermal runaway phenomena caused by lithium precipitation after charging, which will reduce the safety of the battery.

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