Stack Type Jelly Roll for Secondary Battery
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Solution Overview
Problem
Existing secondary battery jelly roll manufacturing methods face challenges in balancing energy density and process efficiency, with winding methods increasing width and reducing energy density, while Z-folding methods improve energy density but slow down the process and destabilize electrode alignment.
Innovation Solution
A stack type jelly roll configuration that combines winding and Z-folding forms, where electrodes are stacked in a winding form at the center and outer side, and in a Z-folding form between, with a method involving continuous winding and folding of separators to optimize electrode alignment and reduce separator usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If winding manner is used to manufacture jelly roll, then ease of manufacture is improved, but energy density decreases and separator usage increases
Solution Approach 1:
The jelly roll is divided into multiple stacks, each stack containing a subset of electrodes and separators. This segmentation allows for more efficient packing of active materials while reducing the overall width and separator consumption compared to a single large winding structure.
Solution Approach 2:
Multiple electrode layers and separators are nested within each stack in a compact arrangement. The stacks are then arranged in sequence to form the complete jelly roll, creating a nested structure that maximizes energy density while minimizing separator usage.
2Quantity of substance
If Z-folding manner is used to manufacture cell stack, then energy density increases and separator usage decreases, but process speed decreases and alignment stability deteriorates
Solution Approach 1:
The manufacturing process is segmented into distinct stages: first forming individual stacks with proper electrode alignment, then assembling multiple stacks in sequence. This segmentation enables faster processing compared to traditional Z-folding while maintaining high energy density through compact stack arrangement.
Solution Approach 2:
Electrodes and separators are pre-assembled into properly aligned stacks before final assembly. This preliminary action ensures stable alignment is achieved during stack formation, eliminating the alignment instability issues of Z-folding methods while maintaining high productivity.
3Quantity of substance
If Z-folding manner is used to manufacture cell stack, then energy density increases, but alignment stability deteriorates
Solution Approach 1:
The cell stack is segmented into multiple independent stacks, each with its own electrode and separator arrangement. This segmentation allows for precise control of electrode alignment within each stack, maintaining manufacturing precision while achieving high energy density through compact overall structure.
Solution Approach 2:
Each stack is designed with local optimization of electrode and separator placement to ensure proper alignment and contact. This local quality control maintains manufacturing precision in each individual stack while the overall compact arrangement achieves high energy density.
Data Source
AI summary
The present invention relates to a stack type jelly roll for a secondary battery including a cathode, an anode, and a separator. More particularly, the present invention relates to a stack type jelly roll for a secondary battery having a hybrid form of a winding stack manner and a zigzag type stack manner, and a method of manufacturing the same.