Pouch Cell Double-Sided Anode Parallel Folding
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Solution Overview
Problem
Pouch batteries, particularly lithium primary batteries, face challenges in achieving optimal performance and safety, especially when scaling up, due to limitations in energy density and safety hazards associated with traditional folding methods and material utilization.
Innovation Solution
A pouch battery design featuring a stacked structure with a double-sided anode and parallel folds, where the anode is half the size of the cathode, and the cathode and separator are of similar dimensions, with the anode being active on both sides, and the use of parallel folding to reduce cell size and enhance material utilization, improving energy density and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional folding methods (spiral wound or zig-zag) are used to reduce cell size, then the battery can achieve compact dimensions, but energy density and material utilization are compromised
Solution Approach 1:
The anode is divided into two separate sheets (anode 1 and anode 2) that are positioned on opposite sides of the cathode, allowing each sheet to be optimized independently and improving overall material utilization without increasing cell volume
Solution Approach 2:
The patent transitions from traditional single-sided anode configuration to a double-sided anode arrangement, effectively utilizing both sides of the cathode structure to improve energy density without compromising cell dimensions
2Quantity of substance
If the anode current collector is made the same size as the cathode and folded in two, then material utilization is improved, but the complexity of the folding process and potential for lithium fragmentation increase
Solution Approach 1:
The anode is segmented into two separate sheets of appropriate size that can be independently positioned and secured, eliminating the need for complex folding of a single large anode sheet and reducing the risk of lithium fragmentation
Solution Approach 2:
Instead of folding a single large anode sheet in half, the patent uses two separate anode sheets positioned on opposite sides of the cathode, inverting the traditional approach to achieve better material utilization with simpler construction
3Quantity of substance
If pouch batteries are scaled up to meet increasing demands, then capacity is improved, but safety hazards increase due to non-optimum conditions
Solution Approach 1:
The electrode assembly is segmented into distinct layers (cathode, separator, anode 1, anode 2) that can be independently optimized for safety, allowing better control of lithium distribution and reduced risk of thermal runaway in larger capacity batteries
Solution Approach 2:
The separator is positioned between the cathode and anode sheets, acting as an intermediary safety barrier that prevents direct contact between electrodes and reduces safety hazards in scaled-up battery designs
Data Source
AI summary
An electrode assembly is formed by respectively overlaying a sheet cathode 1, a sheet separator 3 and a double-sided sheet anode 8 to form a stacked structure 10, and subjecting the stacked structure to multiple folds, wherein the initial fold comprises folding the cathode in half around the double-sided anode so as to surround the respective upper and lower active anode surfaces thereof. The multiple folds may comprise one or more subsequent parallel folds made with the fold line D-D extending perpendicular to the original length of the stacked structure such that its overall length is halved at each fold. A pouch battery comprising said electrode assembly has improved safety and performance characteristics. The pouch battery construction has especial application to lithium primary batteries.