Coil type battery plate group and battery comprising the same

Abstract

The invention discloses a wound battery polar pack and a battery including the battery polar pack, which relate to the technical field of batteries. The wound battery polar pack comprises a positive plate and is characterized in that a winding head end of the positive plate is provided with a thin coated section. The battery comprises the wound battery polar pack which comprises the positive plate and the battery is characterized in that the positive plate is provided with the thin coated section close to the winding head end. In the invention, as the winding head end of the positive plate is provided with the thin coated section, compared with the battery which is not provided with the thin coated section and has the same volumetric specific energy, the battery can reduce the compaction density of the positive plate at the position, thus improving the tensile strength of the positive plate, reducing the stress concentration of the positive plate at the folding place of the section and avoiding possible fracture trouble of the positive plate at the position.

Description

technical field [0001] The invention relates to the technical field of batteries, and more specifically relates to a wound battery pole group and a battery comprising the battery pole group. Background technique [0002] High-end batteries represented by lithium-ion batteries have always been the preferred energy source for electronic communication products due to their high specific energy, high voltage, environmental protection and safety, and long service life. With the continuous improvement of mobile phone functions, such as the emergence of 3G and 4G mobile phones, the requirements for battery specific energy and safety are getting higher and higher. [0003] In order to ensure the consistency of the product and improve its safety, the battery electrode group of the high-end battery is generally made by winding the battery electrode group, and the winding is carried out automatically by mechanization. Figure 1a-Figure 1e What is given is a schematic diagram of forming...

AI Technical Summary

Problems solved by technology

In this winding method, the positive electrode sheet 2 is located on the inner side of the winding, 1-2 creases before the winding head of the positive electrode sheet (i.e. Figure 1a The radius of curvature of A, B in the middle) is small, and because the bend of the first fold cannot form an arc during winding (the edge of the second fold or above after winding is arc), resulting in stress concentration; and at the same time for To increase the volume specific energy of the battery, the compaction density of the positive electrode sheet is now made larger, close to its critical value. When the compaction density of the electrode sheet is larger, its tensile strength will decrease accordingly. In order to ensure the edge of the winding Alignment, the pole pieces are under a certain tension during the winding process

Due to the above reasons, when the winding needle is inserted into the winding, the positive electrode sheet is easily broken at the other creases of the first folded electrode sheet, resulting in loss of battery capacity and serious safety hazards.

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