Solid-State Battery Electrode Assembly for Internal Pressure Buffering
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Solution Overview
Problem
Conventional pouch-type secondary batteries experience a reduction in lifetime due to changes in internal pressure caused by volume expansion and contraction during charging and discharging, which is not effectively managed by existing technologies.
Innovation Solution
An electrode assembly with polymer layers on both ends, having a specific thickness and yield strength, is integrated into the battery structure to control internal pressure changes, utilizing a sulfide-based solid electrolyte and elastic polymer materials like silicone resin to buffer volume fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional pouch-type battery structure is used with electrode leads protruding, then battery can be manufactured with standard sealing process, but internal pressure changes during charging/discharging adversely affect battery lifetime
Solution Approach 1:
A polymer layer is introduced as an intermediary component between the electrode assembly and the exterior member. This polymer layer acts as a buffer that absorbs and mitigates the adverse effects of internal pressure changes during charging and discharging, thereby protecting the battery structure and extending battery lifetime while maintaining compatibility with standard sealing processes.
Solution Approach 2:
The polymer layer is pre-installed between the electrode assembly and the exterior member before the battery is sealed. This beforehand cushioning structure is designed to anticipate and absorb the pressure changes that will occur during subsequent charging and discharging cycles, preventing damage to the battery structure and maintaining reliability over time.
2Reliability
If thermal fusion is performed with sealing member on film for upper and lower parts, then sealing properties are improved, but complexity of sealing process increases
Solution Approach 1:
The polymer layer serves multiple functions simultaneously: it improves sealing properties by filling gaps and enhancing the bond between the electrode assembly and exterior member, while also acting as a pressure buffer during battery operation. This multi-functionality eliminates the need for separate sealing members, thereby improving sealing quality without increasing process complexity.
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 electrode assembly effectively manages internal pressure changes, enhancing the battery's lifetime by maintaining structural stability and preventing lithium dendrite formation, thereby improving capacity retention rates.
Implementation Method 1
polymer layers are comprised on both ends of the electrode assembly... having a specific thickness and yield strength... to control internal pressure changes
Implementation Method 2
solid electrolyte layer... comprising a sulfide-based solid electrolyte
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to an electrode assembly comprising a plurality of electrode structures comprising a positive electrode, a negative electrode, and a solid electrolyte layer disposed the positive electrode and the negative electrode, and polymer layers at both ends of the electrode assembly, and a secondary battery comprising the same.