Secondary Battery Case Structure to Minimize Pouch Cell Dead Space
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Solution Overview
Problem
The existing pouch type secondary batteries suffer from dead space due to deviations in the sealing part, leading to reduced energy density.
Innovation Solution
A case for secondary batteries with recessed shapes and symmetrical or asymmetrical recess parts connected by a connection part, allowing for a V-shaped unfolding and minimizing shape deformation, thereby reducing dead space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional battery case structure is used, then the manufacturing process is simple, but the battery cannot withstand repeated charging and discharging cycles due to electrode expansion and contraction
Solution Approach 1:
The battery case is divided into a case body and a separate case cover, allowing the case body to remain simple while the case cover incorporates the complex compensation structure. This segmentation enables the simple case body to maintain manufacturing ease while the specialized case cover provides the necessary compensation functionality for electrode expansion and contraction during charging cycles.
Solution Approach 2:
The positive electrode assembly is nested within the case cover, which itself is attached to the case body. This nested structure allows the case cover to move relative to the case body, accommodating electrode volume changes while maintaining overall structural integrity and enabling repeated charging cycles.
2Adaptability or versatility
If the case cover is tightly fixed to the case body, then the structural strength is high, but the electrode assembly cannot accommodate volume changes during charging and discharging
Solution Approach 1:
The case cover is designed with dynamic attachment to the case body through protrusions and recesses that allow controlled relative movement. This dynamic connection enables the case cover to move independently to accommodate electrode volume changes during charging and discharging, while maintaining sufficient structural strength through the interlocking protrusion-recess mechanism.
3Ease of manufacture
If a simple case structure is used, then the manufacturing cost is low, but the electrode assembly lacks proper positioning and fixing
Solution Approach 1:
The case cover incorporates localized positioning structures (protrusions and recesses) only where needed for electrode assembly fixation, while the rest of the case structure remains simple. This localized complexity provides precise electrode positioning and securing without requiring the entire case structure to be complex, maintaining ease of manufacture while achieving necessary positioning precision.
Data Source
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AI summary
Disclosed are a case for a secondary battery and a secondary battery. According to an aspect of the present invention for achieving the above object, a case for a secondary battery, in which an electrode assembly having a structure, in which electrodes and separators are alternately disposed, is accommodated, includes: a first recess part and a second recess part, each of which has a recessed shape; a circumferential part configured to surround a circumference of each of the first recess part and the second recess part when the case is unfolded; and a connection part provided between the first recess part and the second recess part to connect the first recess part to the second recess part, wherein, when the case is unfolded, the connection part has a shape that is recessed from each of the first recess part and the second recess part in one direction.