Battery Tab and Leading Plate Structure to Prevent Breakage
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Solution Overview
Problem
Existing energy storage devices face issues with tab deformation leading to increased device size and risk of tab damage due to interference with protective leading plates, which can result in breakage.
Innovation Solution
The tab is fixed to the second principal surface of a second plate in the leading plate, reducing interference with the leading end portion and incorporating an insulating member to prevent contact, thus minimizing breakage and device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lithium secondary battery is charged at a high charge rate, then the charge time is reduced, but lithium ion deposition occurs on the negative electrode and battery performance deteriorates
Solution Approach 1:
A porous coating layer is introduced as an intermediary between the negative electrode and lithium ions. This coating layer mediates the interaction by providing a controlled environment for lithium ion insertion, preventing direct contact between lithium ions and the negative electrode surface that would cause deposition. The coating layer acts as a buffer zone that maintains battery performance even during high-rate charging.
Solution Approach 2:
The coating layer is designed with a porous structure having specific pore volume and average pore diameter. This porous structure allows efficient lithium ion transport while preventing aggregation and deposition. The pores provide multiple pathways for lithium ions, reducing current density concentration and preventing harmful deposition during high-rate charging while maintaining good rate capability.
2Quantity of substance
If the positive and negative electrode areas are made large to increase capacity, then the battery output increases, but the battery volume increases
Solution Approach 1:
A thin porous coating layer is applied to the negative electrode surface. This thin film structure provides the necessary functional properties for preventing lithium ion deposition while occupying minimal volume. The coating layer's thin nature allows maximizing electrode area and capacity without proportionally increasing battery volume, thus improving capacity density.
3Productivity
If a porous coating layer with large specific surface area is formed on the negative electrode, then lithium ion insertion is promoted, but the coating layer thickness increases and battery volume increases
Solution Approach 1:
The coating layer utilizes a porous structure where the specific surface area is derived from internal pore surfaces rather than external thickness. This allows achieving high lithium ion insertion rates through the porous network without requiring a thick coating layer. The pores provide extensive surface area for lithium ion interaction while maintaining a compact overall structure.
Solution Approach 2:
The specific surface area is increased by utilizing the three-dimensional pore structure rather than simply increasing coating layer thickness in one dimension. The porous network provides extensive surface area through vertical and lateral pore walls, effectively moving from a two-dimensional surface area concept to a three-dimensional volumetric surface area, achieving high insertion rates without proportional volume increase.
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 configuration prevents tab breakage while reducing the energy storage device's accommodation space, ensuring stable fixation and enhanced joining strength.
Implementation Method 1
a porous coating layer which allows for rapid charge and discharge cycles to be performed, and which suppresses deterioration of battery performance due to aggregation of lithium ions
Data Source
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AI summary
An energy storage device (10) includes a current collector (negative electrode current collector 150), electrode body (400) that includes a body portion (430) and a tab (420) projecting from the body portion (430), and a leading plate (negative electrode leading plate 155) that connects the current collector and the tab (420). In the leading plate, first and second plates (156) and (157) facing each other are continuously connected at end portions thereof. In the first plate (156), the current collector is fixed to a first principal surface (156a) on the opposite side to the second plate (157). In the second plate (157), the tab (420) is fixed to a second principal surface (157a) on the opposite side to the first plate (156).