Folded Bipolar Electrode Structure for Battery Volume Change Buffering
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Solution Overview
Problem
Existing all-solid secondary batteries with bipolar structures face challenges in designing a structure that can absorb volume changes due to lithium deposition reactions, leading to severe thickness variations and increased risk of short circuits.
Innovation Solution
Incorporating a current collector with a folded structure and a compression pad inside the folded structure to create a buffer space that absorbs volume changes during charging and discharging, thereby protecting the anode layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bipolar structure is used in all-solid secondary batteries, then the number of parts is reduced and high power and high energy density are achieved, but the structure cannot absorb volume changes due to lithium deposition reactions
Solution Approach 1:
The buffer layer is nested within the folded current collector structure, creating an integrated design where the buffer layer is positioned between the folded portions of the current collector. This nesting approach allows the buffer function to be incorporated without adding separate external components, thus reducing overall device complexity while maintaining volume change absorption capability
Solution Approach 2:
The current collector is divided into multiple functional zones: active material deposition areas and folded buffer regions. The folding creates distinct segments where some portions accommodate volume expansion while others maintain electrical connectivity, allowing the structure to handle volume changes without compromising the bipolar configuration
2Power
If a bipolar structure is used in all-solid secondary batteries, then high power and high energy density are achieved, but severe thickness variations occur leading to increased risk of short circuits
Solution Approach 1:
The folded current collector structure creates a buffer layer in advance, before volume changes occur during lithium deposition. This pre-positioned buffer acts as a cushion that absorbs expansion forces, preventing severe thickness variations and maintaining safe distances between electrodes to avoid short circuits
Solution Approach 2:
The current collector structure is designed with variable thickness regions created by folding. The buffer zones have increased thickness to accommodate volume expansion, while active material regions maintain optimal thickness for performance. This parameter variation allows the structure to adapt to volume changes without compromising reliability
Data Source
AI summary
An electrode structure, a bipolar all-solid secondary battery including the same, and a method of manufacturing the electrode structure are provided. The electrode structure includes: a current collector having a first surface and a second surface, wherein the first surface includes a first portion, a second portion, and an intermediate portion between the first portion and the second portion, the first portion and the second portion are arranged toward the outside in opposite directions to each other around the intermediate portion, and the second surface has an inward-folded structure; a cathode active material layer formed on the first portion of the first surface; an anode active material layer formed on the second portion of the first surface; and a compression pad arranged inside the inward-folded structure of the current collector.