Zigzag Folded Battery Strip Electrode Group
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Solution Overview
Problem
The challenge is to miniaturize batteries with high energy density while avoiding the need for lead terminals, which complicates soldering to circuit substrates and increases costs due to larger mounting areas and increased component counts, especially when current collectors are thin and difficult to handle.
Innovation Solution
A battery design featuring a strip-shaped electrode group folded in a zigzag pattern with terminals connected to bent portions on the side faces, allowing for thin current collectors without damage and maintaining reliability through distributed terminal connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lead terminals are added to enable soldering to circuit substrates, then the battery can be connected to external circuits, but the battery size increases and mounting area is required
Solution Approach 1:
The patent merges the terminal function with the battery structure itself by using the current collectors as terminals. The current collectors are extended to the outer peripheral surface of the battery case, eliminating the need for separate lead terminals. This integration reduces the overall battery volume and eliminates additional mounting requirements while maintaining electrical connectivity to circuit substrates.
2Quantity of substance
If current collector thickness is reduced to increase active material layer rate and capacity, then energy density increases, but handling becomes difficult and terminal formation without damage is challenging
Solution Approach 1:
The patent segments the current collector into two functional zones: a thin current collector portion within the battery that maximizes active material layer rate, and a thick current collector terminal portion that extends to the outer peripheral surface for easy handling and terminal formation. This segmentation allows the thin current collector to achieve high energy density while the thick terminal portion provides mechanical strength for handling and soldering operations without damaging the thin current collector.
3Quantity of substance
If current collector thickness is reduced to less than 5 μm to increase capacity, then active material layer rate increases, but welding lead terminals becomes difficult and current collector damage occurs
Solution Approach 1:
The patent segments the current collector into a thin current collector portion (thickness less than 5 μm) for high active material layer rate and a thick current collector terminal portion (thickness 5 μm or more) for reliable terminal connection. The thick terminal portion provides sufficient mechanical strength and surface area for reliable welding of lead terminals, while the thin current collector portion maximizes capacity. This segmentation ensures both high active material layer rate and reliable terminal connection without current collector damage.
Data Source
AI summary
A battery of the present invention has a strip-shaped electrode group. The electrode group includes a first electrode, a second electrode, and a separator interposed therebetween. The first electrode has a strip-shaped first current collector and a first active material layer carried on one surface thereof. The first active material layer faces the separator. The second electrode has a strip-shaped second current collector and a second active material layer carried on one surface thereof. The second active material layer faces the separator. The electrode group is folded in a zigzag pattern to form a laminate having a plurality of flat portions, at least one first bent portion located on a first end side of the plurality of flat portions in which the first current collector is located on the outermost side, and at least one second bent portion located on a second end side that is opposite to the first end side in which the second current collector is located on the outermost side. The laminate has a first terminal connected to the at least one first bent portion and a second terminal connected to the at least one second bent portion.