Electrode plate and lithium ion battery

Abstract

The invention provides an electrode plate which comprises a current collector layer, a first conductive layer, an outer conductive layer and a first silicon material layer, wherein the first conductive layer is arranged on the surface of the current collector layer; the first silicon material layer is arranged on the surface of the outer conductive layer; n groups of silicon material layers and conductive layers are sequentially and alternatively arranged between the first conductive layer and the first silicon material layer. The invention further provides a lithium ion battery which comprises the electrode plate provided by the technical scheme of the invention. According to the electrode plate, the conductive layers have a relatively good buffer function on the silicon material layer, after lithium is embedded, the size of the silicon material layer is increased, then conductive layers on two sides can be compressed, in a lithium removed state, the size of the silicon material layer is reduced and the thickness is recovered, and the conductive layers on two sides are elastic and can be recovered to original thickness, so that due to the multi-layer electrode plate structure, a sufficient buffer space can be provided for the silicon material layer, and along with shrinkage of the silicon material layer, relatively good stability and interface contact property of the multi-layer structure can be maintained, and adverse influence caused by silicon material size change in the battery circulation process can be avoided.

Description

technical field [0001] The invention relates to the technical field of ion batteries, in particular to an electrode sheet and a lithium ion battery. Background technique [0002] In recent years, due to the pressure of environmental pollution and energy scarcity, countries are striving to find environmentally friendly and sustainable energy sources. Green, high-energy and environment-friendly energy storage devices such as lithium-ion batteries and supercapacitors, which appeared in the 1990s, have become the most eye-catching power sources due to their advantages such as high energy density, long cycle life, and high working pressure. [0003] The traditional lithium-ion battery is made of metal oxide and graphite, and its energy density is 150Ah / kg. However, this lithium-ion battery with low energy density cannot meet the current market demand for consumer digital products and power products. Silicon has a capacity ten times higher than the energy density of graphite, and...

AI Technical Summary

Problems solved by technology

[0004] However, silicon materials have a large volume change effect during the cycle, and this volume change effect can reach 300%. This huge volume change will cause the disconnection between silicon particles and the surrounding auxiliary materials, and it is easy to lose electrons and ion channels. Lead to the destruction of the electrode structure, resulting in capacity fading, and the solid / solid interface between the electrode coating layer and the current collector will deteriorate due to the volume change of the silicon electrode layer, and cause electrons to fail to normally transport from the current collector to the electrode coating. In addition, due to the volume change of the silicon particles, the adhesion between the silicon particles and the binder will decrease, and some particles will fall off the electrode surface and enter the electrolyte, which will cause damage to the battery. great security risk

Images