Laminated lithium ion battery and production process thereof

Abstract

The invention discloses a laminated lithium ion battery. The laminated lithium ion battery comprises a lithium ion battery cell, wherein the lithium ion battery cell comprises positive electrode plates, a belt type negative electrode plate and membranes, the belt type negative electrode plate is of a continuous non-cutting belt type structure and is wrapped by two layers of membranes to form a coating body, and the two layers of membranes are marked as a first membrane and a second membrane from top to bottom; the coating body is continuously folded to form a Z shape, the positive electrode plates are arranged at the folding parts of the Z-shaped coating body, and the sequence along the vertical direction is: the first membrane, the belt type negative electrode plate, the second membrane, the positive electrode plate, the second membrane, the belt type negative electrode plate, the first membrane and the positive electrode plate, and then the sequence is repeated. Compared with the conventional laminated battery, the laminated lithium ion battery has the advantages that the negative electrode is not cut and forms the coating body together with the membranes to be folded together, so that the production efficiency is improved, and the battery safety and the rate property are better.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery manufacturing, and in particular relates to a manufacturing process of a laminated lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in various digital products, energy storage and power equipment because of their advantages such as high energy density, small self-discharge, wide operating temperature range, long service life, and no environmental pollution. Density, high-power energy storage, and power markets have shown obvious advantages. However, due to the constraints of the manufacturing process, it is difficult for lithium-ion batteries to achieve high rates, safety and efficiency. [0003] At present, commercial lithium-ion manufacturing processes are mainly divided into winding and stacking processes. Among them, the winding process is to make the positive electrode sheet and the negative electrode sheet in the form of long strips, sepa...

AI Technical Summary

Problems solved by technology

[0007] 2. The above invention adopts belt-type positive and negative electrode sheets to be continuously bent and folded, and the adjacent parts of the belt-type diaphragms on the positive and negative electrode sides are bent and inserted into single positive and negative electrode sheets, and the belt-type negative electrode sheet and single-piece negative electrode sheet are along the main core. The width direction of the body extends to one side of the negative electrode lug connection section. The negative electrode lugs derived from this process include the continuous lugs drawn from the belt-type negative electrode sheet and the tabs drawn from the single-piece negative electrode. The two lugs need to be connected in parallel. Lead out together after welding, and copper foil, as the current commercial lithium ion negative electrode collector, is also the tab that is drawn out for the negative electrode sheet of the above invention. Its welding difficulty is much greater than that of positive electrode current collector aluminum foil, especially when there are many layers The spot welding of the copper foil led by the inner single-piece negative electrode is prone to false welding and missing welding. In this case, the negative electrode of the false welding cannot be charged and discharged normally. In addition to the serious loss of battery capacity, the When the positive electrode is charged and discharged, lithium ions are normally deintercalated, but there is no corresponding intercalation of the negative electrode material. Lithium ions can only accumulate on the negative electrode side to form lithium dendrites. The dendrites pierce the separator and cause an internal short circuit, resulting in battery explosion, fire and other hazards.

Images