Lithium ion power battery

Abstract

The invention belongs to the field of lithium ion batteries and in particular relates to a lithium ion power battery. The lithium ion power battery comprises a shell, a space ring, a cover plate, a battery roll core group and electrolyte, wherein the battery roll core group consists of roll cores; and the shell is of a polygonal structure, so the storage quantity of the electrolyte increases, the dryness of the electrolyte is avoided, opening deformation is realized, the internal pressure of the battery is small, and the safety performance and the cycling performance of the battery are effectively improved. Each roll core is formed by winding a positive pole piece, an isolating membrane and a negative pole piece, wherein the positive pole piece and the negative pole piece are respectively connected with one tab; the tabs pass through the space ring and are welded on the cover plate; and the cover plate is welded with the shell. The roll cores are of cylindrical structures, so that the positive pole pieces and the negative pole pieces, which are isolated by the isolating membranes, are in closer contact, internal resistance is reduced, and winding formation is avoided. An electric core is S-shaped, so that the performance exertion of the battery can be enhanced and the cycling performance of the battery is improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a lithium ion power battery. Background technique [0002] With the rapid development of the electronics industry and the information industry, people have higher and higher requirements on the power supply of various electrical appliances. Cylindrical lithium-ion batteries are used as high-energy power sources in a variety of mobile devices, such as mobile phones, digital cameras, notebook computers, and portable power tools. [0003] Generally, lithium batteries can be mainly divided into square lithium batteries and cylindrical lithium batteries in terms of their shape. When the square lithium battery is wound, the positive and negative electrodes separated by the diaphragm inside the cell are not in close contact, which makes it difficult for the electrolyte to wet the electrode and diaphragm. In addition, during the winding process, the tension of the separator is unev...

AI Technical Summary

Problems solved by technology

When the square lithium battery is wound, the positive and negative electrodes separated by the diaphragm inside the cell are not in close contact, which makes it difficult for the electrolyte to wet the electrodes and diaphragm.

In addition, during the winding process, the tension of the separator is uneven and the tension is too high, which is easy to cause winding deformation, resulting in the appearance of the S shape of the battery cell, and the excessive expansion of the pole piece during the charging and discharging process, which increases the internal resistance and reduces the capacity, thereby affecting the battery performance. performance, and more seriously shorten cycle life

[0004] However, the space of the cylindrical lithium battery shell is relatively narrow, and the amount of electrolyte is relatively small. When the closed mouth is formed, the internal pressure is large, the capacity is low, and the safety performance and cycle performance are not good.

In the process of overcharge charging, the voltage is too high during constant current charging, the electrolyte decomposes to generate gas, and is exhausted, causing the battery to swell, causing a sharp increase in internal resistance, the battery temperature rises sharply, and the diaphragm melts, causing the battery to explode, which is safe. greatly reduced performance

At present, there is no good solution in the industry to solve the degradation of the cycle performance of cylindrical batteries due to the dryness of the electrolyte.

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