Folded Bipolar Electrode Structure for Lithium Deposition Swelling
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Solution Overview
Problem
Designing a bipolar all-solid secondary battery structure that can absorb volume changes due to lithium deposition reactions is challenging, leading to potential short circuits and performance deterioration.
Innovation Solution
Incorporating a compression pad made of elastic materials within a folded current collector structure, which absorbs volume changes of the anode layer during charging and discharging, thereby protecting the anode and improving battery durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a bipolar structure is used to increase energy density and power, then the number of parts is reduced and high currents can flow, but the structure cannot absorb volume changes due to lithium deposition reactions
Solution Approach 1:
The current collector is divided into a rigid outer frame structure and an inner space region, separating the structural support function from the volume absorption function. This allows the outer frame to maintain structural integrity for high current flow while the inner space can accommodate volume changes from lithium deposition.
Solution Approach 2:
The active material layers are nested within the folded current collector structure, with the anode active material layer containing a lithium deposition layer that can expand into the inner space. The compression pad is nested within the same inner space to provide compression and absorption capability.
2Reliability
If the anode structure is made rigid to maintain structural integrity, then short circuits are prevented, but volume changes from lithium deposition cause performance deterioration
Solution Approach 1:
The inner space is designed in advance to accommodate the expected volume expansion of the lithium deposition layer during charging. The compression pad is pre-positioned to provide cushioning and compression force, preventing structural damage and maintaining reliability while allowing for volume changes.
Solution Approach 2:
The current collector uses a folded structure with an inner space that provides flexible accommodation for volume changes. This flexible design allows the structure to adapt to lithium deposition volume changes while the outer frame maintains structural integrity to prevent short circuits.
3Duration of action of stationary object
If a compression pad is added to absorb volume changes, then battery durability is improved, but the device complexity increases
Solution Approach 1:
The compression pad is integrated into the same inner space as the lithium deposition layer, combining the volume absorption function with the existing bipolar structure. This merging approach adds the durability function without requiring a completely separate structural system.
Solution Approach 2:
The inner space of the folded current collector serves multiple functions: it accommodates the lithium deposition layer, provides volume absorption capacity, and houses the compression pad. This multi-functionality reduces the need for additional separate components.
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
The solution effectively absorbs volume changes, enhancing the durability and performance of bipolar all-solid secondary batteries by providing a buffer structure within the current collector, reducing the risk of short circuits and improving charge-discharge efficiency.
Implementation Method 1
The compression pad is made of an elastic material comprising at least one selected from polyurethane, natural rubber, spandex, butyl rubber (isobutylene isoprene rubber, IIR), fluoroelastomer, ethylene-propylene rubber (EPR), styrene-butadiene rubber (SBR), chloroprene, elastin, epichlorohydrin rubber, nylon, polyterpene, isoprene rubber, polybutadiene, nitrile rubber, thermoplastic elastomer, silicone rubber, ethylene-propylene-diene rubber (EPDM), ethylene vinyl acetate (EVA), halogenated butyl rubber, and neoprene
Data Source
Figure 1
Figure 2(a)~2(d)
Figure 3
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.