Curved Tab Bundle Layout for Higher-Density Power Storage Cells
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Solution Overview
Problem
The volume taken up by the tab bundle in power storage cells increases with the number of electrode sheets stacked, reducing the energy density due to non-uniform space utilization.
Innovation Solution
The lengths of current-collecting tabs are varied and arranged in a curved configuration within the cell, with specific cut end faces aligned or non-aligned to minimize volume and enhance heat dissipation, allowing for efficient space utilization and electrolyte permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of electrode sheets stacked together increases, then the battery capacity increases, but the volume of the tab bundle increases and takes up more space inside the case, reducing energy density
Solution Approach 1:
The patent applies curvature by arranging the tab bundle in a curved or bent configuration within the case rather than a straight linear arrangement. This curvature allows the tab bundle to occupy less space by utilizing three-dimensional space more efficiently, reducing the volume occupied while maintaining the necessary length for electrical connection, thereby resolving the contradiction between battery capacity and tab bundle volume.
Solution Approach 2:
The patent transitions from a one-dimensional linear arrangement of tabs to a three-dimensional curved arrangement. By bending the tab bundle and arranging it in a curved path within the case, the invention utilizes additional spatial dimensions to reduce the projected volume occupied by the tab bundle, allowing more electrode sheets to be stacked without proportionally increasing tab bundle space occupation.
2Volume of stationary object
If the lengths of current-collecting tabs are made different from one another, then the tab bundle volume is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by making the lengths of current-collecting tabs non-uniform, where tabs at different positions within the bundle have different lengths. Specifically, tabs closer to the curved inner side are shorter while tabs at the outer side are longer. This localized variation in tab length optimizes the curved arrangement and reduces overall volume while maintaining manufacturability through systematic length differentiation rather than complete irregularity.
3Volume of stationary object
If the tab bundle is arranged in a curved state, then space utilization is improved, but heat dissipation may be affected
Solution Approach 1:
The patent addresses heat dissipation in the curved tab bundle arrangement by applying local quality through varied tab lengths. Tabs positioned at different locations within the curved bundle have different lengths, with outer tabs being longer to expose more surface area for heat dissipation. This compensates for the potential heat accumulation issue in curved arrangements by optimizing the thermal characteristics at different locations within the bundle.
Data Source
AI summary
A power storage cell includes a case and an electrode stack. The case accommodates the electrode stack. The case includes a case body and a cap. The case body has an opening. The opening is closed by the cap. The cap has an electrode terminal provided thereto. The electrode stack is formed of a plurality of electrode sheets stacked together. Each of the plurality of the electrode sheets has a current-collecting tab. The plurality of the current-collecting tabs are stacked together to form a tab bundle. At at least part of the tab bundle, lengths of the plurality of the current-collecting tabs are different from one another. The tab bundle is bonded to the electrode terminal. Inside the case, the tab bundle is accommodated in a curved state.