Lithium Battery Case Laminate for Nail Penetration Resistance
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in suppressing short circuits and heat generation when metal foreign substances penetrate the battery casing, which can lead to safety issues.
Innovation Solution
A case for a rechargeable lithium battery is designed with a laminate sheet having an inner, middle, and outer layer, and featuring a first polymer film with a polyurethane resin on the outer layer and optionally a second polymer film on the inner layer, which provides high friction, elongation rate, and tensile strength to prevent penetration and maintain integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional laminate sheet structure is used without additional polymer films, then the device complexity is reduced and manufacturing is easier, but the battery cannot suppress short circuits and heat generation when metal foreign substances penetrate the casing
Solution Approach 1:
The patent applies composite materials by combining a laminate sheet with polymer films having specific properties (friction coefficient 0.3 or higher, elongation rate 200% or higher, tensile strength 200 kgf/cm2 or higher). This composite structure prevents metal foreign substances from penetrating through the battery case, thereby suppressing short circuits and heat generation while maintaining structural integrity.
Solution Approach 2:
The patent applies local quality by specifying particular properties for the polymer film layers at critical locations. The polymer films are configured with high friction coefficient, high elongation rate, and high tensile strength specifically at the outer and inner layers of the laminate sheet, providing localized protection against penetration without requiring the entire structure to be uniformly complex.
2Reliability
If polymer films with high friction coefficient, elongation rate, and tensile strength are added to the case, then penetration prevention and safety are improved, but the manufacturing process and device complexity increase
Solution Approach 1:
The patent applies parameter changes by specifying critical threshold values for the polymer film properties: friction coefficient of 0.3 or higher, elongation rate of 200% or higher, and tensile strength of 200 kgf/cm2 or higher. By defining these parameter ranges, the patent enables manufacturers to select from various materials that meet the requirements, simplifying the manufacturing process while ensuring penetration prevention performance.
Data Source
AI summary
A case for a rechargeable lithium battery, the case for the rechargeable lithium battery including a laminate sheet in which an inner layer, a middle layer, and an outer layer are sequentially laminated; and a first polymer film on the outer layer of the laminate sheet and including a first polyurethane resin.