Battery Pouch Sheath for Mechanical Protection
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Solution Overview
Problem
Conventional pouch-type lithium secondary batteries are prone to damage during mounting in electronic devices due to the softness of the pouch, which can lead to mechanical stress and potential electrical short-circuits.
Innovation Solution
A secondary battery design that incorporates a sheath made of materials with higher mechanical strength, such as stainless steel or synthetic resin, to enclose the pouch and enhance its durability, with the sheath being formed as a foil with specific surface portions to cover and reinforce the pouch's sides and rear surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a soft pouch is used to enclose the electrode assembly, then the battery weight is reduced and flexibility is improved, but the pouch is easily damaged during mounting in electronic devices
Solution Approach 1:
The patent applies nesting by placing the soft pouch inside a rigid sheath, creating a nested structure where the pouch is enclosed within the sheath. This allows the battery to maintain the weight advantages of the soft pouch while gaining the mechanical protection of the rigid sheath, directly resolving the contradiction between pouch durability and structural complexity.
Solution Approach 2:
The patent creates a composite structure combining the soft pouch material (typically aluminum foil and polymer layers) with a rigid sheath material (such as stainless steel or hard resin). This composite construction provides both the flexibility and light weight of the pouch and the strength and damage resistance of the rigid sheath, solving the durability issue without excessive complexity.
2Strength
If a rigid sheath is added to protect the pouch, then the battery's mechanical strength is improved, but the contact area with electronic devices increases
Solution Approach 1:
The patent applies local quality by providing rigid sheath protection only at specific locations where mechanical damage is most likely to occur during mounting, rather than completely enclosing the entire pouch. This selective reinforcement protects the pouch where needed while minimizing the overall contact area with electronic devices, resolving the contradiction between protection and contact area.
3Strength
If the sheath thickness is increased to enhance protection, then the pouch damage resistance is improved, but the battery capacity is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the sheath thickness to a specific range that provides sufficient mechanical protection while minimizing the volume occupied by the sheath itself. By carefully controlling this critical parameter, the battery maintains adequate capacity while gaining the necessary damage resistance, resolving the contradiction between protection and capacity.
Data Source
AI summary
A secondary battery includes an electrode assembly having first and second electrodes and a separator, a pouch type case for receiving the electrode assembly, and a sheath for enclosing outer sides of the case. The sheath can prevent damage to the pouch in electronic devices to which the secondary battery is applicable as an inner pack type.