Folded Electrode Foil Edges for Compact Low-Impedance Batteries
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Solution Overview
Problem
The challenge in battery manufacturing is to reduce the size and weight of lithium-ion batteries while maintaining high energy density, which is often compromised by the manufacturing process, leading to increased costs and potential product damage.
Innovation Solution
A battery manufacturing process that forms a shaped pattern on electrode foils with a 'stepped' or 'staircase' pattern, using laser cutting to create strips which are then folded inwardly to reduce impedance and avoid physical damage, thereby reducing manufacturing costs and increasing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the size and weight of batteries are reduced, then energy density is improved, but manufacturing complexity increases and product damage risk increases
Solution Approach 1:
The electrode foil is divided into multiple regions with different widths, creating a stepped pattern that allows for differentiated processing zones. This segmentation enables the manufacturing process to handle different sections optimally, reducing overall complexity while maintaining reduced battery size
Solution Approach 2:
Strips are pre-formed on the electrode foil before the winding process. This preliminary action allows the folding and connection processes to occur more efficiently after winding, reducing manufacturing complexity in the critical size-reduction phases
2Weight of moving object
If the size and weight of batteries are reduced, then energy density is improved, but product damage increases
Solution Approach 1:
The strips are formed on the electrode foil before winding, allowing the folding process to occur in a controlled manner after the roll is formed. This prevents damage that would occur if folding attempted to happen on already-compressed small batteries
Solution Approach 2:
Instead of folding the electrode strips before winding into a compact roll, the patent performs the folding operation after winding. This inverted sequence protects the fragile folded strips from damage during the high-pressure winding process while still achieving the space-saving benefits
3Shape
If a rubbing process is used to planarize the edge of the roll configuration, then surface finish is improved, but product wear increases
Solution Approach 1:
Instead of rubbing the edge to achieve planarity, the patent inverts the approach by folding the strips inward to create the desired edge configuration. This eliminates the harmful rubbing process while achieving the necessary shape for proper battery assembly
Solution Approach 2:
The harmful rubbing process is completely removed from the manufacturing sequence. The patent extracts this unnecessary step and replaces it with the folding process, eliminating physical damage to the foil while still achieving proper edge configuration
4Object-generated harmful factors
If more strips are formed in the shaped pattern, then impedance is reduced, but manufacturing complexity increases
Solution Approach 1:
The electrode is divided into multiple strips through laser cutting, creating multiple parallel conduction paths. This segmentation reduces electrical impedance by distributing the current flow across multiple channels, while the systematic pattern keeps manufacturing complexity manageable
Solution Approach 2:
The number, width, and spacing of strips are adjustable parameters that can be optimized to achieve target impedance values. By changing these parameters, the manufacturing process can be adapted to different impedance requirements without fundamentally altering the process complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process allows for a reduction in battery size and weight while maintaining high energy density, reducing manufacturing costs and avoiding product damage, and allows for adjustable impedance by varying the number of strips formed in the pattern.
Implementation Method 1
performing the folding process may include using a rotary tool (such as a rotary blade) to apply force to fold in the strips inwardly toward the axis of the roll configuration
Implementation Method 2
forming, in each of the regions of the shaped pattern, one or more strips (or 'flags'), such as by laser cutting incisions in the shaped pattern
Data Source
AI summary
A battery includes an anode, a cathode, one or more separators, and an electrolyte. The anode, the cathode, the one or more separators, and the electrolyte are disposed in a roll configuration. At least one of the anode or the cathode includes a foil portion having a plurality of bent portions in different widths that are bent inwardly toward an axis of the roll configuration and that define an edge of the roll configuration.