Square lithium ion battery

Abstract

The invention provides a square lithium ion battery, the square lithium ion battery comprises a square shell and a cover plate, the square shell is internally provided with at least one roll core, the roll core comprises a positive plate and a negative plate which are arranged at two sides of a diaphragm, the positive plate comprises a positive current collector, and the negative plate comprises a negative current collector. The positive plate comprises a positive current collector and a positive active material coating area at least partially covering one surface of the positive current collector, and the negative plate comprises a negative current collector and a negative active material coating area at least partially covering one surface of the negative current collector; the square lithium ion battery meets the following conditions: (T / (30 * n)) 0.5 / V * Sc is greater than or equal to 3.0 and less than or equal to 5.0; according to the square lithium ion battery provided by the invention, the number of the roll cores and the coating area of the positive and negative active materials can be flexibly designed, the selection of the number of the roll cores and the coating area of the positive active materials and the size of the battery are limited, and the space utilization rate of the roll cores is improved, so that the mass energy density of the battery is improved; design is reasonable, operability is high, and popularization is facilitated.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to the design of a square lithium ion battery, in particular to a square lithium ion battery. Background technique [0002] Square aluminum shell lithium-ion batteries have become one of the mainstream choices for vehicle power batteries and energy storage batteries due to their high structural reliability, good safety, and easy arrangement. In order to improve the energy density of square aluminum shell batteries, it is necessary to Try to improve the space utilization rate inside the aluminum shell. At present, there are methods such as doubling the number of tabs and rationally setting the structure of the square battery. [0003] CN108461811B discloses a pole piece and an electric core for a winding lithium ion battery. The pole piece includes a pole piece body, and the pole piece body is provided with a plurality of tabs, and the plurality of tabs are divided into n...

AI Technical Summary

Problems solved by technology

[0006] To sum up, the prior art considers the relationship between the height and width of the square shell, the design of the internal structure of the square battery and the design of the material coating area in order to obtain higher energy density for wound batteries, but ignores the The influence of the number of winding cores corresponding to different sizes of shells and the area of ​​the positive and negative coatings

Too few winding cores will make the thickness of a single winding core too large, resulting in a waste of space at the corner; too many winding cores will increase the space required for tab welding, resulting in a waste of space under the cover

The area of ​​the active material coating area is the same, if it is too small, the space in the winding core will be wasted, and if it is too large, the energy density will decrease because the current collector occupies too much weight

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