Rolled Battery Cell Assembly With Folded Electrode Ends for Heat Transfer
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Solution Overview
Problem
Lithium-ion batteries face issues with overheating when large loads are applied due to the small current tabs, and they are also heavy due to their metallic jacket.
Innovation Solution
The battery design incorporates folded portions on the electrodes to increase the contact surface area with the end caps, improving current and heat transfer, and uses a non-conductive flexible or rigid jacket to reduce weight and enhance thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If small tabs are used for current transfer, then the battery structure is simple, but the battery overheats when large loads are applied
Solution Approach 1:
The electrode is divided into multiple tabs instead of using a single large tab. This segmentation increases the total surface area for current transfer and heat dissipation, allowing the battery to handle large loads without overheating while maintaining structural simplicity
Solution Approach 2:
The tabs are folded back and forth to create a three-dimensional structure with increased surface area. This dimensional transformation allows the tabs to provide adequate current transfer and thermal management without increasing the overall footprint of the battery
2Reliability
If a metallic jacket is used to encase the battery, then the battery is protected, but the battery weight increases significantly
Solution Approach 1:
The heavy metallic jacket is completely removed from the battery design. The battery relies on the structural integrity of the wound electrode assembly and alternative protective measures, eliminating the source of excessive weight while maintaining necessary protection
Solution Approach 2:
The battery uses a composite structure combining the flexible separator material with the electrode assembly itself to provide both structural support and protection, replacing the need for a separate metallic jacket
3Loss of energy
If folded portions are added to electrodes, then current and heat transfer is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The tabs are folded back and forth during the winding process itself, rather than requiring separate folding operations afterward. This preliminary action integrates the complex folding step into the existing manufacturing workflow, minimizing additional complexity while achieving improved current and heat transfer
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 design significantly reduces thermal hot spots and weight, making the battery more thermally efficient and lightweight, while maintaining efficient current transfer.
Implementation Method 1
improving current and heat transfer
Implementation Method 2
improving current and heat transfer, significantly reduces thermal hot spots
Data Source
AI summary
A battery cell assembly, including a rolled cell formed from a first electrode and a second electrode rolled together about a longitudinal axis. The rolled cell includes a primary section in which the first electrode and the second electrode overlap in a radial direction from the longitudinal axis, and a first extension end extending from a first longitudinal end of the primary section and formed from a first edge section of the first electrode. The first edge section includes a first folded portion folded to contact an adjacent portion of the first edge section. The battery cell assembly further includes a first end cap coupled to the rolled cell and contacting the first folded portion.