Secondary Battery Stepped Case Folded Part Insulation
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Solution Overview
Problem
Secondary batteries face challenges in increasing energy density while preventing damage to the folded parts of their battery cases, which can lead to insulation issues due to cracks during the folding process.
Innovation Solution
A secondary battery design featuring a battery case with a stepped part to accommodate a folded portion and an electrode assembly with a corresponding stepped protrusion, which enhances energy density and prevents insulation damage by securely seating and sealing the folded part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the sealed portion of the battery case is folded to increase energy density, then the energy density is improved, but the folded part may be damaged in insulation due to cracks
Solution Approach 1:
The battery case is divided into multiple sealed portions, with only specific portions being folded while others remain intact. This segmentation allows the folded portions to increase energy density while the non-folded sealed portions maintain insulation integrity and prevent cracks from compromising the entire battery case.
Solution Approach 2:
Different portions of the battery case have different properties: some portions are designed to be folded (with appropriate sealing) to increase energy density, while other portions maintain full sealing and insulation properties. This local differentiation allows the system to achieve both high energy density and reliable insulation simultaneously.
2Quantity of substance
If the sealed portion is folded to maximize energy density, then the energy density is improved, but the folded part may separate and become unfixed
Solution Approach 1:
The sealed portions are folded and fixed in advance during the battery assembly process, before the battery is put into service. This preliminary folding and fixing ensures that the folded portions maintain their intended configuration and do not separate or become unfixed during subsequent handling or operation, while still achieving the desired energy density increase.
3Quantity of substance
If the entire outer surface is folded to increase energy density, then the energy density is improved, but the manufacturing complexity increases
Solution Approach 1:
Only specific portions of the outer surface are folded to increase energy density, rather than folding the entire outer surface. This selective folding approach maintains manufacturing simplicity by limiting the number of folding operations required, while still achieving the goal of increased energy density through efficient space utilization.
Data Source
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AI summary
A secondary battery according to the present invention comprises an electrode assembly in which an electrode and a separator are alternately stacked and a battery case accommodating the electrode assembly therein, wherein the battery case comprises a stepped part that is disposed to be stepped, an outer surface of the battery case is sealed to allow a folded part to be seated on the outer surface of the stepped part, and the electrode assembly comprises a stepped protrusion that is stepped in a shape corresponding to an inner surface of the stepped part disposed on the battery case.