Rectangular Battery Tab Layout for Higher Energy Density
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Solution Overview
Problem
Rectangular secondary batteries used in EVs and HEVs face challenges in achieving higher volume energy density and larger battery capacity due to space constraints within the battery case.
Innovation Solution
The design incorporates a tab group on the positive or negative electrode plates, connected to a current collector member via an insulator with a base portion and a first wall portion that protrudes towards the electrode body, allowing for a more efficient use of space and preventing direct contact between the tab group and the casing, thereby enhancing volume energy density and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the rolled positive-electrode-core exposed portion and rolled negative-electrode-core exposed portion are disposed in left and right spaces within the battery case, then the battery structure is simplified, but the volume energy density decreases due to wasted space
Solution Approach 1:
The patent changes the spatial arrangement of the tab group from a distributed left-right configuration to a concentrated sealing plate side configuration. By moving all tabs to one side (sealing plate side) and bending them to connect to the current collector member along the sealing plate, the invention utilizes the longitudinal dimension of the battery case more effectively, eliminating the need for left and right spaces and thereby increasing volume energy density.
2Quantity of substance
If the tab group is disposed on the sealing plate side of the electrode body, then the volume energy density increases, but the risk of direct contact between tabs and casing increases
Solution Approach 1:
The patent introduces an insulator as an intermediary component between the tab group and the rectangular casing. The insulator includes a base portion disposed between the sealing plate and the current collector member, and a first wall portion that protrudes toward the electrode body to position the tab group away from the casing. This intermediary structure prevents direct contact between the conductive tab group and the casing, eliminating short circuit risk while maintaining the space-efficient configuration.
3Quantity of substance
If the tab group is bent and connected to a region of the current collector member along the sealing plate, then the space utilization is optimized, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-bending the tab group before assembly into the battery. The tab group is bent to form a predetermined shape that allows it to connect to the current collector member along the sealing plate. This pre-forming of the tab group simplifies the overall assembly process and enables the space-optimized configuration to be achieved through a single, well-defined manufacturing step rather than complex in-situ adjustments.
Data Source
AI summary
A rectangular secondary battery includes a rectangular casing that contains an electrode body, a sealing plate that seals an opening of the rectangular casing, a first positive electrode tab group that is composed of a plurality of positive electrode tabs, a positive electrode terminal that is attached to the sealing plate, a second positive electrode current collector that constitutes a positive electrode current collector member that is electrically connected to the first positive electrode tab group and the positive electrode terminal, and a second insulator. The second insulator includes a base portion that is disposed between the sealing plate and the second positive electrode current collector. The first positive electrode tab group is bent and connected to the second positive electrode current collector, the region being disposed along the sealing plate. A first wall portion is disposed between the first positive electrode tab group and the rectangular casing.