Recessed Tab for Thinner Battery Current Collectors
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Solution Overview
Problem
Conventional battery manufacturing processes are limited by the thickness of the current collector layer, which affects mechanical stability, Equivalent Series Resistance (ESR), and solderability, leading to constraints on energy density and battery capacity in stacked-cell batteries.
Innovation Solution
The method involves stabilizing the active material layer independently of the current collector layer, forming a recess in the active material layer to accommodate a thinner current collector layer and recessed tab elements, allowing for reduced current collector thickness while maintaining mechanical stability and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the current collector layer thickness is reduced to increase energy density, then the battery capacity and energy density improve, but the mechanical stability, Equivalent Series Resistance (ESR), and solderability deteriorate
Solution Approach 1:
The tab element is nested within a recess formed in the active material layer, allowing the tab to be partially supported by the active material layer itself. This nesting arrangement enables the use of a thinner current collector layer while maintaining mechanical stability, as the recess provides structural support for the tab element without requiring a thick current collector layer.
Solution Approach 2:
The tab element is positioned in three-dimensional space within the recess, extending from the outer surface toward the interior portion of the active material layer. This spatial arrangement in multiple dimensions allows the tab to achieve proper mechanical support and electrical connectivity without requiring increased current collector thickness, thereby resolving the contradiction between thin current collector and mechanical stability.
2Quantity of substance
If the current collector layer thickness is reduced to increase energy density, then the battery capacity and energy density improve, but the Equivalent Series Resistance (ESR) increases
Solution Approach 1:
The tab element nested within the recess of the active material layer provides an additional conductive path that compensates for the increased ESR associated with a thinner current collector layer. The tab element's direct connection to the active material layer reduces the overall resistance, allowing energy density to improve without excessive ESR penalty.
3Quantity of substance
If the current collector layer thickness is reduced to increase energy density, then the battery capacity and energy density improve, but the solderability deteriorates
Solution Approach 1:
The tab element is nested within the recess and can be configured to extend to or near the outer surface of the active material layer, providing adequate surface area and geometry for soldering operations. This arrangement ensures proper solderability even when the current collector layer is thin, as the tab element itself serves as the soldering surface rather than relying on the current collector layer thickness.
4Length of stationary object
If the current collector layer thickness is reduced to enable thinner batteries, then the battery thickness decreases, but the mechanical stability and structural integrity deteriorate
Solution Approach 1:
The recess in the active material layer provides structural support for the tab element, effectively replacing the mechanical support function that would otherwise be provided by a thick current collector layer. This allows the battery to be made thinner while maintaining structural integrity, as the recess-containing active material layer assumes the load-bearing role.
Solution Approach 2:
The tab element is positioned within the three-dimensional volume of the active material layer, utilizing the depth of the recess to achieve proper mechanical support. This spatial arrangement allows the battery to be thinner in the z-dimension while maintaining structural integrity through the volumetric distribution of support within the active material layer.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Various embodiments are described herein for an electrode assembly for a battery and a method of making the electrode assembly. The electrode assembly comprises an active material layer having a recess formed therein at an outer surface of the active material layer, the recess extending from a side facet of the active material layer toward an interior portion of the active material layer; a current collector layer supported on and in electrical contact with the outer surface of the active material layer; and a tab element supported partially within the recess and in electrical contact with at least one of the active material layer and the current collector layer, the tab element being adapted to provide an electrical connection for the electrode assembly.