Pouch Cell Electrode Structure for Nail-Penetration Short-Circuit Risk
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Solution Overview
Problem
Lithium-ion batteries face a risk of short-circuit and explosion due to nail penetration, which causes the positive and negative electrode members to be short-circuited, leading to fires and explosions.
Innovation Solution
A secondary battery design featuring an electrode assembly with an insulating substrate, a conductive layer, and a conductive structure, where the conductive layer is thin to minimize burr formation and the welding area is arranged obliquely to reduce space occupation, enhancing safety and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick conductive layer is used, then electrical conductivity is improved, but burr formation increases causing short-circuit risk
Solution Approach 1:
The patent applies this principle by using a thin conductive layer (thickness of 0.1-10 micrometers) instead of a thick conductive layer. The thin conductive layer is formed on the insulating substrate and provides sufficient electrical conductivity while minimizing burr formation during nail penetration tests, thereby reducing short-circuit risk between positive and negative electrode members.
Solution Approach 2:
The patent applies this principle by changing the thickness parameter of the conductive layer from conventional thick layers to a specific thin range (0.1-10 micrometers). This parameter change optimizes the balance between electrical conductivity and burr formation, where the thin conductive layer maintains necessary conductivity while significantly reducing the quantity of material that can form harmful burrs during penetration events.
2Reliability
If a large welding area is used, then electrical connection is improved, but space occupation increases reducing energy density
Solution Approach 1:
The patent applies this principle by arranging the welding area obliquely relative to the insulating substrate rather than in a conventional flat configuration. The conductive structure extends from the conductive layer at an angle, creating a three-dimensional welding configuration that reduces the projected area occupied on the substrate while maintaining adequate electrical connection surface area. This dimensional change allows improved electrical connection without proportionally increasing space occupation, thereby preserving energy density.
Data Source
AI summary
Provided is a secondary battery, comprising an electrode assembly, a packaging bag, and electrode leads. The electrode assembly is accommodated in the packaging bag and comprises a first electrode member, a second electrode member and a separator. The separator separates the first electrode member from the second electrode member. The first electrode member comprises an insulating substrate, a conductive layer, an active material layer and a conductive structure. The conductive layer is provided on the surface of the insulating substrate, and the conductive layer is provided with a first portion and a second portion. The first portion is coated with the active material layer. The second portion is not coated with the active material layer. The conductive structure is welded to the second portion to form a first welding area. The electrode leads are connected to the conductive structure and extend to the outside of the packaging bag.