Lithium ion energy storage device and pre-lithiation and production method thereof

Abstract

The invention provides a lithium ion energy storage device and a pre-lithiation and production method thereof. One or more pre-lithiation electrodes are arranged at a preset distance outside a battery cell of the lithium ion energy storage device in a direction vertical to a pole piece, and then the pre-lithiation electrodes are charged or discharged with a positive electrode and a negative electrode so that lithium ions in the pre-lithiation electrodes enter the electrode through gaps among the positive electrode, the negative electrode and the diaphragm along the direction parallel to an electrode plate, and the pre-lithiation method avoids the design scheme that the lithium ions must penetrate through the electrode plate of the energy storage device along the vertical direction in the traditional pre-lithiation method. The method completely overcomes the defect that a positive electrode foil and a negative electrode foil must be hole foils and the negative influence on the production efficiency and the finished product quality caused by the hole foils so that the production process is simpler and more controllable, meanwhile, the technology can also be used for secondary lithium supplement operation of the finished product lithium ion energy storage device, and help is provided for regeneration of the lithium ion energy storage device.

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 and its pre-lithiation and preparation methods. Background technique [0002] New 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, and are important for the development of lithium-ion energy storage devices with higher energy density and power density. direction, but these materials usually have low first-time efficiency, and they need to be pre-lithiated in order to fully exert the performance of the material in the actual use process. [0003] At present, there are many pre-lithiation schemes to choose from. Among them, the pre-lithiation of the negative electrode by using the third ...

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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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