Flat Secondary Battery Sidewall Terminal for Higher Energy Density
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Solution Overview
Problem
Existing flat secondary batteries have not achieved sufficient energy density per unit volume, necessitating improvements in their configuration to optimize space utilization.
Innovation Solution
A flat secondary battery design featuring a battery can with a curved and plane surface, where the electrode terminal is coupled to the sidewall, eliminating crimped joints and allowing for a stacked electrode assembly within a columnar package member, thereby increasing the device space volume and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crimped joints are used to seal the battery case, then sealing reliability is improved, but device space volume is reduced due to the space occupied by crimped parts
Solution Approach 1:
The patent removes the crimped joint structure from the battery case design. Instead of using crimped parts to seal the case, the invention uses a different sealing approach that eliminates the need for crimping operations, thereby recovering the space that would have been occupied by crimped joints and improving overall device space volume.
Solution Approach 2:
Rather than using crimped joints to achieve sealing (conventional approach), the patent inverts the approach by using a sealing structure that integrates directly into the case without requiring separate crimped components. This reversal of the conventional sealing method eliminates the space penalty associated with crimped joints.
2Volume of stationary object
If a laminated film case with curved surfaces is used to increase internal space utilization, then device space volume is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs curved surface geometry in the battery case design, specifically using arc-shaped sidewalls that transition between bottom parts. This curvature allows for more efficient space utilization compared to purely flat surfaces, while the patent addresses manufacturing considerations through appropriate forming processes.
Solution Approach 2:
The case is divided into distinct segments including first and second bottom parts connected by sidewall parts with curved surfaces. This segmentation allows each part to be optimized independently for both space utilization and manufacturability, with the curved surfaces providing smooth transitions between segments.
3Ease of operation
If electrode terminals are led from the plane surface to the outside, then ease of installation is improved, but device space volume is reduced due to space occupied by terminal routing
Solution Approach 1:
The patent provides specific local modifications to the case structure at the terminal leading positions, including recesses or openings in the sidewall parts. These localized features facilitate easy installation of terminals while minimizing the overall space consumed by terminal routing, as the terminals pass through dedicated pathways rather than occupying general internal volume.
Data Source
AI summary
A flat secondary battery includes an outer package member, a battery device, and an electrode terminal. The outer package member has a flat and columnar shape, and includes a pair of bottom parts and a sidewall part. The bottom parts are opposed to each other. The sidewall part lies between the bottom parts. At least a portion of a surface of the sidewall part is a curved surface. The battery device is contained inside the outer package member and includes a positive electrode and a negative electrode. The electrode terminal is provided to be exposed at the sidewall part and is coupled to one of the positive electrode and the negative electrode.