A kind of lithium ion energy storage device, its pre-lithiation, and preparation method

Abstract

The invention provides a lithium ion energy storage device, its pre-lithiation, and a preparation method. Specifically, one or more lithium ion energy storage devices are provided at a predetermined distance outside the cell of the lithium ion energy storage device and in a direction perpendicular to the pole piece. The pre-lithiation electrode is then charged or discharged by the pre-lithiation electrode and the positive electrode and the negative electrode, so that the lithium ions in the pre-lithiation electrode pass through the gap between the positive electrode, the negative electrode and the separator along the direction parallel to the electrode sheet. Entering the inside of the electrode, this pre-lithiation method avoids the design scheme that lithium ions must pass through the pole piece of the energy storage device in the vertical direction in the traditional pre-lithiation method, and completely overcomes the need for positive and negative foils to be holes. The disadvantages of foil and the resulting adverse effects on the preparation efficiency and finished product quality make the preparation process simpler and more controllable. At the same time, this technology can also be used for the secondary lithium replenishment operation of finished lithium ion energy storage devices, which is a lithium ion energy storage device. The regeneration of the energy storage device helps.

Description

technical field [0001] The invention belongs to the technical field of pre-lithiation methods for lithium-ion energy storage devices, and in particular relates to a lithium-ion energy storage device suitable for the preparation of non-porous foils, its pre-lithiation, and a preparation method. Background technique [0002] Novel anode materials such as hard carbon materials, silicon-based materials, and graphene materials usually have higher specific capacity and better rate performance than traditional graphite materials, which are important for developing lithium-ion energy storage devices with higher energy and power density. However, these materials usually have low first-time efficiency, and they need to be pre-lithiated in the actual use process so that the performance of the material can be fully exerted. [0003] At present, there are various pre-lithiation schemes to choose from, among which the use of the third electrode containing lithium to pre-lithiate the negat...

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Problems solved by technology

In this method, the lithium-containing third electrode is usually placed on the outer surface or between some inner layers in the direction parallel to the electrode sheet, and at the same time, in order to make lithium ions pass through the foil to reach the surface of the remaining electrodes during the process of pre-intercalating lithium , it is necessary to make holes on the foil, such as electrochemically corroding the foil to form micro-holes that are partially penetrated, or using laser and mechanical stamping to make holes on the foil, which greatly increases the production cost

Moreover, although this method solves the problem of pre-intercalating lithium in the negative electrode, it will seriously restrict the subsequent coating process. When coating the first side, the material will leak to the second side, which greatly affects the coating process. The difficulty of coating greatly reduces the efficiency of coating and further increases the manufacturing cost. At the same time, the holes on the foil will lead to a series of other problems such as the decrease of the strength of the foil and the decrease of electrical conductivity, which will affect the electrochemical performance of the prepared lithium-ion energy storage device.

This phenomenon lies in the fact that the coating thickness is usually less than 50 μm or even lower power devices, and the aluminum foil with a foil thickness of less than 10 μm and the copper foil with a thickness of less than 6 μm are more serious, which brings great impact to the preparation of these lithium-ion energy storage devices. Difficulties

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