Lithium supplementation device and lithium supplementation method for negative pole piece of lithium ion battery

Abstract

The invention provides a lithium ion battery negative pole piece lithium replenishing device and a lithium supplementing method, which belong to the technical field of lithium ion batteries, and the specific scheme is as follows: a lithium ion battery negative pole piece lithium replenishing device, including an unwinding device and a winding device , an electrolyte tank containing an ionic liquid electrolyte and at least one lithium supply device, the lithium supply device is arranged in the electrolyte tank and soaked in the ionic liquid electrolyte, and one end of the negative pole piece to be replenished with lithium is wound on the unwinding On the device, the other end passes through the lithium supply device and is wound on the winding device. The lithium supply device includes a metal lithium source, a lithium ion conductor sheet and a current collector plate, and the metal lithium source is arranged between the lithium ion conductor sheet and the current collector plate And in contact with the lithium ion conductor sheet and the current collector plate surface, the negative electrode sheet to be replenished with lithium is located on the side of the lithium ion conductor sheet away from the metal lithium source, the current collector plate is electrically connected to the positive pole of the power supply, and the negative electrode sheet to be replenished is electrically connected Negative pole of the power supply. The lithium replenishment device is simple and effective, and the lithium replenishment is uniform, safe and reliable.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a lithium-replenishment device and a lithium-replenishment method for a negative pole piece of a lithium-ion battery. Background technique [0002] Lithium-ion battery is a rechargeable battery composed of positive electrode, negative electrode, separator and electrolyte or electrolyte. It has the characteristics of high voltage, high energy density, long cycle life and environmental friendliness. It is widely used in portable electronic devices and electric vehicles. , and gradually show application prospects in large-scale energy storage devices. At present, graphite is mostly used as the negative electrode material of commercial lithium-ion batteries, and the theoretical specific capacity is 372mAh / g. The actual development is close to the theoretical value. Therefore, there is very limited space for increasing the energy density of lithium-ion batter...

AI Technical Summary

Problems solved by technology

Therefore, when these high-capacity negative electrode materials are used to match the positive electrode materials, a large amount of lithium ions will be consumed by the negative electrode materials during the first charge and cannot return to the positive electrode, resulting in a greatly reduced actual overall capacity of the battery. The effect of increasing the overall capacity of the battery severely limits the application of high specific capacity negative electrodes

[0004] In order to solve the problem of low charge and discharge efficiency of the negative electrode material for the first time, it is an effective solution to supplement the negative electrode with excess lithium to compensate for the loss of lithium during the first charge process.

The Chinese invention patent with the application number 201310094757.7 discloses a device and method for continuous lithium replenishment on both sides of the negative electrode sheet. The lithium powder is adsorbed on the surface of the negative electrode sheet by the action of an external electric field, and then the lithium powder is adhered to the negative electrode sheet by a rolling device. On the surface, because lithium powder is very active, there is a great potential safety hazard, and lithium powder floating objects will cause great harm to the working environment and workers' health

The Chinese invention patent application with the application number CN201510015441.8 discloses a device and method for replenishing lithium on the negative electrode sheet. The lithium strip and the negative electrode sheet are bonded together by cold pressing of the lithium strip to realize lithium supplementation. However, the ultra-thin lithium strip production There are also technical difficulties such as low yield, high cost, and poor uniformity. When supplementing lithium with lithium sheets with uneven thickness, there will be problems with local excessive lithium supplementation and poor battery cycle performance.

The utility model patent with the application number CN201520748174.6 discloses a device for continuously replenishing lithium on the negative electrode sheet. The electrode sheet is soaked in the electrolyte tank through the winding and unwinding device, and the metal lithium and the separator are covered on the surface of the roller. Lithium supplementation in the chip, the electrolyte used in this method is volatile, flammable and explosive, and the diaphragm used in this method has low strength and is easy to be punctured by metal lithium dendrites or other foreign objects to cause a short circuit of the device, so this method still has a very large safety risk. Hidden danger

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