Secondary Battery Lead Element Spacing for Energy Density
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Solution Overview
Problem
Existing secondary battery designs for large batteries face limitations in power characteristics and energy density due to a large workforce requirement and structural constraints that result in a significant gap between the electrode assembly and the container, which cannot be minimized effectively.
Innovation Solution
A secondary battery design featuring an electrode assembly with uncoated regions for lead element connection, where the lead elements are spaced apart from the terminals and attach to the outermost portions of these regions, reducing the gap within the container and enhancing current collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the multi-tap structure is used to increase power capacity, then the power characteristics improve, but the manufacturing complexity and workforce requirement increase significantly
Solution Approach 1:
The electrode assembly is divided into multiple segments with separate positive and negative electrodes, each having its own lead element connection point. This segmentation allows current collection from different regions without requiring complex multi-tap structures, thereby improving power characteristics while maintaining manufacturing simplicity
Solution Approach 2:
The invention transitions from a single-plane tap structure to a three-dimensional arrangement where lead elements connect to electrodes at different spatial locations and orientations. This dimensional change enables enhanced current collection and power delivery without increasing manufacturing complexity
2Quantity of substance
If the lead elements are positioned closer to the center to reduce gap, then the energy density improves, but the current collection efficiency deteriorates
Solution Approach 1:
Different regions of the electrode assembly are assigned different functions: the central region is optimized for compactness and energy density, while the peripheral regions are optimized for current collection. Lead elements are strategically positioned to connect at optimal locations that balance both requirements, with each connection point having locally optimized properties
Solution Approach 2:
The uncoated regions serve as intermediary zones between the active material regions and the lead element connection points. These intermediary regions facilitate efficient current collection from the active material while allowing compact positioning of lead elements, thus mediating between energy density and current collection efficiency requirements
3Reliability
If the uncoated regions are made larger to improve lead element connection, then the current collection efficiency improves, but the active material volume and energy density decrease
Solution Approach 1:
Instead of making uncoated regions excessively large, the invention applies partial action by creating strategically positioned uncoated zones that are just sufficient for effective lead element connection. This minimizes the loss of active material while ensuring adequate current collection, avoiding the excessive removal of active material that would occur with larger uncoated regions
Data Source
AI summary
A secondary battery includes: an electrode assembly including positive and negative electrodes; a container adapted to receive the electrode assembly; a cap assembly having at least two terminals exposed outside the container, the cap assembly being adapted to be fixed to the container to seal the container; and lead elements adapted to electrically connect the terminals and the electrode assembly. A center of the terminals are aligned with a center of the electrode assembly, and the lead elements are spaced apart from the center of their respective terminals and adapted to be connected to their respective terminals and the electrode assembly.