Current collector and preparation method thereof as well as electrochemical energy storage device

Abstract

The invention relates to a current collector and a preparation method thereof as well as an electrochemical energy storage device and belongs to the technical field of the electrochemical energy storage devices. The current collector provided by the invention comprises a metal layer, wherein a polymer layer and a metal foil layer are arranged on the metal layer in a direction far away from the metal layer in sequence; the polymer layer comprises an insulating polymer microsphere and a conducting agent. According to the current collector provided by the invention, the polymer layer is arrangedbetween a substrate and the metal foil layer; when the temperature of the current collector is raised to melting or softening temperature of the insulating polymer microsphere in the polymer layer, the insulating polymer microsphere is rapidly melted to form a dense film; the transmission of electrons between the metal foil layer and the substrate is weakened, so that the thermal runaway reactionof a battery is stopped and the safety of a lithium-ion battery in a utilization process is effectively ensured; the safety performance of the battery under the conditions of processes, hot boxes, short circuit and the like is improved.

Description

technical field [0001] The invention relates to a current collector, a preparation method thereof, and an electrochemical energy storage device, belonging to the technical field of electrochemical energy storage devices. Background technique [0002] Lithium-ion batteries have been widely used in the field of portable consumer electronics due to their advantages such as high energy density, high power density, and environmental protection. Under some abuse conditions, such as acupuncture, extrusion, impact, etc., a short circuit inside the battery will cause the battery to catch fire and explode. Therefore, improving the safety of lithium-ion batteries under abuse conditions has become an obstacle that must be overcome to further promote the application of lithium-ion batteries. [0003] The reason for the thermal runaway of lithium-ion batteries under abuse conditions is that the traditional current collector is in contact with the active material layer under short-circuit ...

AI Technical Summary

Problems solved by technology

[0003] The reason for the thermal runaway of lithium-ion batteries under abuse conditions is that the traditional current collector is in contact with the active material layer under short-circuit conditions such as extrusion, acupuncture, and extrusion. This short-circuit contact resistance is small, the current is large, and it is easy to trigger A series of side reactions lead to thermal runaway. For example, the Chinese invention patent application publication number CN102290578A discloses a flexible current collector. The plastic layer and the copper plating layer are two parts, the plastic layer of the positive electrode and the current collector and the abdominal muscle current collector is one of polyethylene plastic, polyvinyl chloride plastic, polypropylene plastic and polystyrene plastic; the flexible current collector It can effectively improve the energy density of lithium-ion batteries, but has the same problem of poor safety performance as other lithium-ion batteries in the prior art

Another example is that the Chinese utility model patent with the authorized announcement number CN206878100U discloses a current collector, the current collector includes a polymer layer and a porous metal foil, and the porous metal foil is arranged on both surfaces of the polymer layer along the thickness direction; The current collector can effectively improve the acupuncture safety performance of lithium-ion batteries, but the improvement of safety performance such as overcharge, hot box and short circuit is not obvious

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