A current collector, a pole piece and a lithium ion battery with a pore-forming functional coating

Abstract

The invention provides a current collector with a pore-forming functional coating, a pole piece and a lithium ion battery, and the current collector with a pore-forming functional coating, comprising a conductive base layer and a functional coating coated on at least one surface of the base layer layer, the functional coating contains a gas-generating compound whose decomposition temperature is below 250°C and can generate gas. The functional layer of the current collector of the present invention is coated with a compound with gas-generating and decomposing properties, which can produce through-holes through the coating by decomposing the gas-generating compound at the bottom of the active coating without affecting the existing coating process. , thereby improving the dynamic performance of battery products. The method is simple, easy to implement, low in cost, suitable for promotion and has high application value.

Description

technical field [0001] The present invention relates to the technical field of lithium ion battery manufacturing, in particular, to a current collector, a pole piece and a lithium ion battery with a pore-forming functional coating. Background technique [0002] Lithium-ion batteries have become one of the most widely used options in energy storage and power battery applications due to their high energy density and long service life. In order to obtain higher energy efficiency and reduce the manufacturing cost of batteries, lithium-ion batteries are often designed to increase the mass ratio of active materials and reduce the amount of auxiliary materials used. However, when the coating amount of active material is increased, the thickness of the coating will inevitably increase, resulting in a longer diffusion path of lithium ions in the battery, hindering the performance of materials close to the current collector, and ultimately affecting the kinetic performance of the batt...

AI Technical Summary

Problems solved by technology

Such a high proportion of pore-forming agents will form a large number of holes in the coating. Although it may improve the kinetic performance of the battery, it may also lead to pits on the membrane surface and uneven distribution of active materials, which will affect the long-term cycle of the battery. During the process, problems such as black spots and lithium precipitation occurred due to uneven lithium intercalation

Moreover, since the decomposition of the pore-forming agent occurs randomly in the wet film formed by the slurry, some pore-forming agents may decompose directly on the surface of the slurry, resulting in waste

CN102655229A proposes a method of using a pore-forming agent to be dissolved and separated and then pressed into the active material coating layer, and then heated and decomposed in the later stage to manufacture a pole piece with through holes, but the channel depth generated by this method depends on the precipitation of the pore-forming agent. Grain size and orientation, with strong randomness, cannot guarantee that the channel will penetrate to the bottom of the active material coating

This method creates an uncoated area on the current collector during the coating process, but in actual use, the uncoated area may be covered by a liquid film due to the surface tension of the slurry, forming a closed hole; in addition, this method requires the equipment to be repaired Retrofitting, using gravure rolls, the cost is higher

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