Combined lithium ion battery and manufacturing method thereof

Abstract

The invention relates to a combined lithium ion battery and a manufacturing method thereof. The combined lithium ion battery comprises N cylindrical casings, N cover caps and N cells, wherein the N cells are directly connected through pole pieces winding around the cells, each cell is connected with a positive pole lug and a negative pole lug, a channel is connected between every two adjacent cylindrical casings, the cells are located in the cylindrical casings, the connection pole pieces are located in the channels, the cover caps cover the cylindrical casings, channel covers connecting the cover caps cover the channels, and each positive pole lug and the corresponding negative pole lug are connected with the corresponding cover cap and a corresponding casing bottom respectively. The manufacturing method comprises steps as follows: the N cells are wound simultaneously with a winding machine with N winding needles, put in the N cylindrical casings and baked, electrolyte is injected into the casings, the cover caps are tightened, and activation, formation and capacity grading are performed. Heat in the battery is distributed uniformly and can be easily dissipated out, the current density is uniform, polarization is balanced, the capacity of a unit cell is effectively increased, and the electrochemical performance of the battery is improved.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a combined lithium ion battery which can effectively improve the electrochemical performance of the battery and a manufacturing method thereof. Background technique [0002] At present, more and more new energy vehicle manufacturers have adopted cylindrical batteries as the first choice for power batteries, and the electrochemical performance of cylindrical batteries has a decisive impact on the entire vehicle. The requirements of electric vehicles for power batteries are: high power, high energy, high energy density, high power density, low cost, long life, abuse resistance / high safety, high reliability, good low temperature characteristics, short charging time and interchangeability Good sex. At present, lithium-ion power batteries for electric vehicles on the market can be divided into three types: winding, lamination and roll lamination in terms of structure, and can be divided into ...

AI Technical Summary

Problems solved by technology

[0013] The invention mainly solves the problem that the original cylindrical lithium-ion battery has a relatively large winding radius and relatively thick thickness, which leads to uneven internal heat distribution, difficult heat dissipation, uneven current density distribution, and unbalanced polarization, which eventually lead to battery cycling. Performance and other electrochemical performance deterioration, and the capacity of the single battery is small, the technical problem of higher battery consistency; provide a combined lithium-ion battery and its manufacturing method, reduce the volume of a single cylindrical lithium-ion battery Around the radius, reduce the relative thickness, ensure uniform internal heat distribution, easy heat dissipation, uniform current density distribution, balanced polarization, improve electrochemical performance such as battery cycle performance, and effectively increase the capacity of the single battery, which is conducive to meeting Battery Consistency Requirements

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