Cylindrical lithium ion battery and manufacturing method therefor

Abstract

The invention belongs to the technical field of lithium batteries and discloses a steel shell type cylindrical lithium ion battery and a manufacturing method therefor. The technical scheme adopted by the invention is as follow: the cylindrical lithium ion battery comprises a cylindrical steel shell, a positive plate, a negative plate and a diaphragm, wherein two sides of each of the positive plate and the negative plate are coated with active substances with corresponding activities; the positive plate, the negative plate and the diaphragm are arranged at intervals and wound into a battery cell; the battery is characterized in that a negative current collector is further arranged on an outer layer of the positive plate, the negative plate and the diaphragm arranged at intervals and is wound into the battery cell together with the positive plate, the negative plate and the diaphragm; a tube body is arranged in the middle of the steel shell; the upper part of the tube body is sealed; the periphery of the lower part of the tube body is hermetically connected with the bottom surface of the steel shell; a lower opening of the tube body is communicated with the outside; two short edges and a long edge of the negative plate are left as uncoated regions; the positive plate is provided with a tab; the diaphragm is longer than a coated region on the negative plate at the starting end of winding and wider than the coated region on the negative plate; the center of the battery cell is inserted in the tube body; and the tab of the positive electrode is opposite to the uncoated region of the negative plate in direction.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and relates to a steel shell cylindrical lithium ion battery and a preparation method thereof. Background technique [0002] Lithium-ion batteries have high energy density, long cycle life, good rate performance and safety performance, and are environmentally friendly. They are currently the main energy products. Steel-cased cylindrical lithium-ion batteries can be in the form of coiled internal cells, and are designed with an explosion-proof combination cap. Therefore, compared with other types of lithium-ion batteries, steel-cased cylindrical lithium-ion batteries have relatively mature technology, high production efficiency, and low cost. Low, good consistency, good safety performance and other advantages, is currently an important lithium-ion battery product. [0003] Although steel-cased cylindrical lithium-ion batteries have been widely used, their volume design is limited. The...

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Problems solved by technology

[0003] Although steel-cased cylindrical lithium-ion batteries have been widely used, their volume design is limited. The cells of steel-cased cylindrical lithium-ion batteries are relatively compact, and the heat dissipation of the steel case is poorer than that of the aluminum case. The diameter is too large or the height is too high. Not conducive to internal heat dissipation of the battery

The quality of spot welding the bottom of the steel shell cylindrical lithium-ion battery negative electrode lug is not easy to detect, and most companies cannot guarantee the stability of the welding machine, and the stability of the bottom quality cannot be fully guaranteed, especially for high-power multi-negative electrodes. For cylindrical lithium-ion batteries with ear structure steel shell, the welding of the negative electrode lug point bottom cannot be stably controlled, which affects the consistency of internal resistance of the battery and the safety of the battery, and restricts high-energy and high-power steel-shell cylindrical lithium-ion batteries to a certain extent. development in special fields

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