Composite ceramic coating, lithium ion battery composite ceramic diaphragm and lithium ion battery

Abstract

The invention belongs to the technical field of a lithium ion battery, and specifically to a composite ceramic coating layer; meanwhile, the invention relates to a lithium ion battery composite ceramic diaphragm using the coating and the lithium ion battery using the diaphragm. The ceramic coating comprises ceramic powder, inorganic carbonate and a binder, wherein the mass ratio of the ceramic powder to inorganic carbonate to binder is 0-0.5:0.1-1:0.02-0.1. According to the composite ceramic diaphragm using the coating, the mechanical strength of the diaphragm is improved, the thermal shrinkage of the diaphragm is reduced, and the problem of overcharging and abuse of the battery is solved; and meanwhile, the safety performance of the battery is improved without affecting the energy density of the battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, specifically relates to a composite ceramic coating, and also relates to a lithium ion battery composite ceramic diaphragm using the coating and a lithium ion battery using the diaphragm. Background technique [0002] Since Japan's Sony (Sony) company took the lead in commercializing lithium-ion batteries, it has been widely used in various fields due to its advantages of high energy density, high voltage, high cycle life, low self-discharge rate, no memory effect and light weight. widely used. The use of lithium-ion batteries in the field of energy storage and power vehicles provides an ideal solution for human beings to solve the environmental problems caused by the use of biofuels. [0003] Compared with the energy density requirements of lithium-ion batteries for consumer electronics, energy storage and power vehicles have higher requirements for lithium-ion batteries. Higher ...

AI Technical Summary

Problems solved by technology

Whether it is a single battery or a single battery assembled into a battery pack, there will be problems such as overcharging and over-discharging during use.

Among them, overcharging is one of the risk factors that cause unsafe behavior of lithium-ion batteries, and the occurrence of overcharging makes the safety risk even greater.

When the lithium-ion battery is overcharged, because the battery voltage rises rapidly with the increase of polarization, it will inevitably cause irreversible changes in the structure of the positive electrode active material and oxidative decomposition of the electrolyte, which will generate a large amount of gas and release a large amount of heat, resulting in the internal discharge of the battery. The pressure and temperature rise sharply, and there are unsafe hazards such as explosion and combustion; at the same time, the surface of the carbon negative electrode in an overcharged state will also reduce its safety due to the deposition of metal lithium.

[0004] At present, the industry has conducted various explorations and proposed various solutions for the overcharge safety of lithium-ion batteries. For example, the patent CN201320203851.7 uses PTC material coating, but this solution has the following defects: first, in the original process route Adding a new process and increasing the process control point will increase the cost of battery manufacturing; secondly, the PTC material coating occupies the internal space of the battery, reducing the energy density of the battery, and this method does not significantly improve energy storage or abuse of power vehicle batteries. question

[0006] Patent CN103996872 uses special electrolyte additives to consume overcharging additives during overcharging to improve battery overcharging and achieve flame retardancy. However, this solution tends to generate harmful gases when the battery is overcharging, and at the same time cannot completely release the internal battery when the battery is overcharging. Energy, failed to achieve the purpose of solving the battery overcharge safety problem

[0007] Patent CN103811727A adopts a positive electrode sheet with a sandwich-type sandwich structure, and first coats lithium manganese phosphate, then coats active materials (lithium nickel cobalt manganese), and finally coats ceramic materials. This method abuses energy storage or power vehicle batteries. , there is no significant improvement, while reducing the energy density of the battery

[0008] In addition, there are lithium salts added to the positive electrode, such as adding 0.1%-5% lithium carbonate to the positive electrode (such as patent CN200810005109.9), spraying lithium carbonate on the surface of the positive electrode (such as patent CN200410052169.8), adding lithium carbonate or calcium carbonate to the positive electrode and lithium phosphate (such as patent CN201110026987.0), but the above technical solution reduces the battery capacity while improving the battery overcharge safety problem

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