Multilayer Battery Lead Wire Insulation for High-Temperature Adhesion
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Solution Overview
Problem
Nonaqueous electrolyte batteries face challenges in maintaining adhesivity between lead wires and enclosing containers at high temperatures, which is critical for quick charging and discharging applications, especially in electric vehicles, due to the need for higher heat resistance and improved adhesivity under elevated conditions.
Innovation Solution
A lead wire for nonaqueous electrolyte batteries is designed with a multi-layer insulating film structure, featuring a conductor-covering layer with acid-modified polyolefin and specific elastic modulus ratios between the first and second insulating layers, which enhances adhesivity by dispersing peel forces and preventing stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer insulating film is used for the lead wire, then the structure is simple and easy to manufacture, but the adhesivity deteriorates at high temperatures causing peeling and leakage
Solution Approach 1:
The insulating film is divided into three distinct layers: a base layer (50-200 μm) providing structural support, an intermediate layer (10-50 μm) with moderate elasticity for stress distribution, and a surface layer (5-20 μm) with high elasticity for adhesion. This segmentation allows each layer to perform its specific function, resolving the contradiction between reliability and complexity by making the complex structure functional and necessary.
Solution Approach 2:
The patent uses composite material structure with different polymer compositions in each layer. The base layer uses high-melting-point materials for thermal stability, the intermediate layer uses materials with moderate elastic modulus for stress distribution, and the surface layer uses materials with high elasticity for adhesion. This composite approach enables the insulating film to maintain adhesivity at high temperatures while managing structural complexity through functional differentiation.
2Reliability
If the insulating film has high elasticity to prevent peeling, then adhesivity improves, but stress concentration may occur leading to other failures
Solution Approach 1:
Different regions of the insulating film have different elastic moduli tailored to their specific functions. The surface layer has high elasticity (0.1-1 GPa) specifically for adhesion and peel resistance, while the intermediate layer has moderate elasticity (1-10 GPa) for stress distribution, and the base layer has high strength for structural support. This local quality differentiation resolves the contradiction by providing high elasticity only where needed for peel resistance while maintaining overall structural strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides excellent adhesivity under high temperatures, preventing peeling and leakage, even at temperatures above conventional limits, thereby ensuring reliable performance and safety for nonaqueous electrolyte batteries.
Implementation Method 1
the conductor-covering layer comprises an acid-modified polyolefin
Implementation Method 2
the ratio (E1/E2) of an elastic modulus E1 of the first insulating layer at any one temperature in the range of 80° C. or more and 125° C. or less to an elastic modulus E2 of the second insulating layer at the same temperature as in the first insulating layer, is 0.10 or more and 10.00 or less
Implementation Method 3
at any one temperature in the range of 80° C. or more and 125° C. or less
Data Source
AI summary
A lead wire for a nonaqueous electrolyte battery of the present disclosure has a conductor, and an insulating film having a plurality of layers and covering at least a part of the outer peripheral surface of the conductor, wherein the insulating film has a conductor-covering layer laminated on a surface of the conductor, a first insulating layer laminated on an outermost surface of the insulating film, and a second insulating layer laminated on an inner surface of the first insulating layer; the conductor-covering layer contains an acid-modified polyolefin; and the ratio (E1/E2) of an elastic modulus E1 of the first insulating layer at any one temperature in the range of 80° C. or more and 125° C. or less to an elastic modulus E2 of the second insulating layer at the same temperature as in the first insulating layer, is 0.10 or more and 10.00 or less.