Gas Diffusion Layer Structure for Crack-Resistant Electrochemical Cells
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Solution Overview
Problem
The existing electrochemical cells face the risk of cracks in the gas diffusion layer due to thermal expansion coefficient differences between the metal substrate and the cell body, leading to potential structural failures.
Innovation Solution
The electrochemical cell design incorporates a gas diffusion layer with a crack-preventing space in its cross-section, strategically located and sized to absorb stress, ensuring the layer's integrity by maintaining a specific width and shape that effectively prevents crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas diffusion layer is disposed between the cell body and metal substrate, then electrical conductivity is improved, but cracks may occur due to thermal expansion coefficient difference
Solution Approach 1:
The gas diffusion layer is designed with spatially varying thickness: a first thickness in the first region (over connecting holes) and a second thickness in the second region (peripheral region), where the second thickness is greater than the first thickness. This local quality variation allows the peripheral region to better accommodate thermal expansion stresses while maintaining electrical conductivity in the central region.
Solution Approach 2:
The thickness parameter of the gas diffusion layer is changed across different regions. By increasing the thickness in the peripheral region where thermal stress concentrates, the layer's resistance to crack propagation is enhanced without compromising the electrical conductivity function in the central region.
2Ease of manufacture
If the gas diffusion layer is made uniform in thickness, then manufacturing is simplified, but stress concentration occurs at the edges leading to cracks
Solution Approach 1:
Instead of a uniform thickness, the gas diffusion layer implements local quality variation with different thicknesses in different regions. The peripheral region has increased thickness to specifically address edge stress concentration, while the central region maintains optimal thickness for electrical conductivity.
Solution Approach 2:
The solution moves from a one-dimensional uniform thickness parameter to a two-dimensional spatially varying thickness distribution. This dimensional change allows the thickness to be optimized independently in different spatial locations to address both manufacturing and reliability requirements.
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
This design effectively prevents cracks in the gas diffusion layer, enhancing the cell's structural reliability and operational stability by managing thermal stress through strategic placement and configuration of the crack-preventing space.
Implementation Method 1
there is concern that a crack may be caused in the gas diffusion layer by stress that occurs between the metal substrate and the gas diffusion layer due to a difference in thermal expansion coefficient between the metal substrate and the cell body
Data Source
AI summary
An electrochemical cell includes: a metal substrate having a principal surface and a plurality of connecting holes formed in the principal surface; and a cell body disposed on the principal surface. The cell body has: a gas diffusion layer disposed on the principal surface, the gas diffusion layer being electrically conductive; a first electrode layer disposed on the gas diffusion layer; a second electrode layer; and an electrolyte layer disposed between the first electrode layer and the second electrode layer. The metal substrate has: a gas-permeable region in which the plurality of connecting holes are formed; and a non-gas-permeable region surrounding the gas-permeable region in a plan view. The gas diffusion layer has: a first region formed on the gas-permeable region; and a second region formed on the non-gas-permeable region. The second region has a crack-preventing space in a cross section along a thickness direction.