Battery Current Collector Layout for Higher Cell Energy Density
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Solution Overview
Problem
In energy storage devices, the space required for connecting a current collector to the electrode assembly leads to pressure on the housing space, making it difficult to improve energy density, especially when the current collector is folded and arranged inside the case.
Innovation Solution
The energy storage device includes a current collector with a terminal connecting portion and an electrode connecting portion, where the electrode connecting portion is thinner than the terminal connecting portion, allowing for a more compact arrangement that improves energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current collector is folded and arranged inside the case to connect the electrode assembly to the wall, then the connection is achieved, but the housing space for the electrode assembly is reduced, making it difficult to improve energy density
Solution Approach 1:
The current collector is divided into multiple portions with different thicknesses: a first current collector portion with greater thickness for reliable connection to the electrode assembly, and a second current collector portion with smaller thickness for arrangement in limited space. This segmentation allows each portion to be optimized for its specific function, resolving the contradiction between connection reliability and space utilization.
Solution Approach 2:
Different portions of the current collector are given different local qualities (thicknesses) according to their functional requirements. The first portion has greater thickness where mechanical strength and electrical conductivity are critical for connection, while the second portion has reduced thickness where space is constrained. This local differentiation optimizes both connection reliability and energy density simultaneously.
2Reliability
If a thicker current collector is used to ensure reliable conduction, then electrical conductivity is improved, but the volume occupied increases, reducing the space for the electrode assembly
Solution Approach 1:
The current collector employs local quality variation by having different thicknesses in different portions. The first current collector portion has greater thickness to ensure reliable electrical conduction and mechanical connection, while the second portion has reduced thickness to minimize volume occupation. This allows the system to achieve adequate conductivity without unnecessarily increasing overall volume.
Solution Approach 2:
The current collector is segmented into functional zones: a first portion where thick construction is necessary for conduction reliability, and a second portion where thin construction is acceptable and desirable for space savings. This segmentation enables optimized electrical performance without excessive material usage.
Data Source
AI summary
An energy storage device that includes a case, an electrode assembly housed in the case, the electrode assembly including an electrode assembly body portion and a tab portion protruding from a part of the electrode assembly body portion in a first direction, a current collector arranged between the electrode assembly and a wall of the case in the first direction, and an electrode terminal fixed to the wall, the current collector includes a terminal connecting portion connected to the electrode terminal and an electrode connecting portion connected to the electrode assembly, the terminal connecting portion and the electrode connecting portion are arranged side by side in a second direction intersecting with the first direction, a thickness of the electrode connecting portion is smaller than a thickness of the terminal connecting portion, and the electrode assembly includes a positive electrode plate and a negative electrode plate.