Pouch Battery Case Stepped Folding to Eliminate Bat Ears
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pouch-type secondary batteries suffer from reduced energy density and deteriorated appearance quality due to the formation of bat ears, which complicate assembly into battery modules and affect the outer appearance.
Innovation Solution
A pouch-type battery case design with a recessed accommodation part, a folding part having a stepped portion, and a terrace part, along with a forming jig that presses the folding part outward to prevent bat ear formation, ensuring a tightly unfolded structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pouch film is folded to form the battery case, then the sealing process speed is improved and the number of trimming processes is reduced, but the folded portion protrudes outward forming bat ears that occupy unnecessary volume and deteriorate appearance quality
Solution Approach 1:
The patent applies preliminary action by pre-forming a stepped portion at the folding part before the folding operation. The stepped portion is created during the drawing process, where the pouch film is stretched to form a first circumferential portion with greater thickness and a second circumferential portion with lesser thickness. This pre-prepared stepped structure allows the folding part to be properly contained within the accommodation part without protruding, thus preventing bat ear formation while maintaining the folding process efficiency
Solution Approach 2:
The patent applies local quality by creating different thickness regions at specific locations of the pouch film. The first circumferential portion has a greater thickness than the second circumferential portion, with the stepped portion located specifically at the folding part. This localized thickness variation ensures that the folding part has sufficient material to form the stepped structure that prevents protrusion, while other areas maintain their original properties
2Ease of manufacture
If the folding part is formed without a stepped portion, then the manufacturing process is simpler, but the folded portion protrudes outward forming bat ears that reduce energy density
Solution Approach 1:
The stepped portion is formed as a preliminary structure during the drawing process before folding. By pre-forming the stepped portion with different thickness regions in the pouch film, the patent ensures that when folding occurs, the material is already configured to prevent protrusion. This eliminates the need for additional post-folding trimming or correction processes, maintaining manufacturing simplicity while preventing bat ear formation that would reduce energy density
Data Source
AI summary
A pouch-type battery case according to an embodiment of the present disclosure may include: an accommodation part having a recessed shape; a folding part disposed at one side of the accommodation part; and a terrace part expanded around the accommodation part. The folding part may have a stepped portion with respect to the terrace part outward in a direction orthogonal to a longitudinal direction of the folding part. A circumference of the accommodation part may include: a first circumferential portion to which the terrace part is connected; and a second circumferential portion configured to connect both ends of the folding part to the terrace part, wherein a thickness of the second circumferential portion may be less than that of the first circumferential portion.