Overcharge-resistant pole piece, method for preparing same, and lithium ion battery

Abstract

The invention provides an overcharge-resistant pole piece, a method for preparing the same, and a lithium ion battery, and belongs to the technical field of lithium ion batteries. The overcharge-resistant pole piece includes an overcharge-resistant coating and a pole piece layer. The overcharge-resistant coating is disposed on both surfaces of the pole piece layer, and includes an overcharge-resistant material. The overcharge-resistant material includes one or more of the group consisting of silicon, oxide of silicon, oxide of tin, titanium dioxide, tungsten oxide, iron oxide, molybdenum oxide, cobalt oxide, copper oxide, and nickel oxide, and lithium titanate. The overcharge-resistant material can consume the lithium dendrites formed during an overcharge process to prevent the lithium dendrites from piercing a diaphragm and further from causing an internal short circuit. Further, the consumption of the lithium dendrite can reduce its side reaction with an electrolyte, thereby improving the battery's overcharge performance. The diaphragm shrinks under a heat abuse condition, and the overcharge-resistant coating on the positive and negative pole pieces can isolate the positive and negative electrodes, avoid internal short circuits, and improve the safety of a battery cell.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to an overcharge-resistant pole piece, a preparation method thereof, and a lithium-ion battery. Background technique [0002] Lithium-ion batteries have been widely used in consumer electronics, energy storage equipment, and new energy vehicles due to their excellent performance. However, because lithium-ion batteries are mainly composed of flammable electrode materials and electrolytes, it is easy to cause self-heating of the battery under abuse conditions, resulting in thermal runaway or even explosion of the battery. This is why lithium-ion battery safety accidents occur frequently and cannot be eliminated. root cause. [0003] Overcharging is a common cause of thermal runaway in Li-ion batteries, which occurs during the charging phase of the battery. Adding overcharge protection additives to the electrolyte is a common method to improve the overcharge...

AI Technical Summary

Problems solved by technology

Therefore, the effect is not good under the condition of high voltage overcharge. Although the electropolymerization compound can improve the overcharge, the material itself will decompose and produce gas during the charge and discharge cycle, resulting in a very low cycle life of the battery cell.

In lithium-ion batteries with PTC-coated pole pieces, PTC is a material with a positive temperature coefficient. The effect of improving the overcharge performance under high current conditions is not good