Solid-State Electrochemical Stack Packaging for Pressure-Balanced Expansion
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Solution Overview
Problem
Solid-state lithium batteries face challenges in packaging due to expansion and contraction during charge and discharge cycles, which can lead to damage from uneven pressure distribution on the solid-state electrolyte.
Innovation Solution
An electrochemical stack assembly is designed with a frame that surrounds the stack, allowing pressure to be applied only to the major surfaces and not the edges, using a laminated pouch that seals under vacuum to prevent damage from atmospheric pressure on the minor surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid-state lithium batteries are packaged in conventional rigid containers, then structural support is provided, but the batteries cannot accommodate expansion and contraction during charge and discharge cycles, leading to deformation or cracking of the solid-state electrolyte
Solution Approach 1:
The patent employs a flexible pouch structure with laminated layers that can expand and contract with the battery while maintaining structural integrity. The pouch includes a body portion that conformally surrounds the battery and flexible tabs that extend from the battery, allowing the packaging to adapt to volume changes during charge/discharge cycles without rigid constraints
Solution Approach 2:
The packaging structure transitions from a static rigid container to a dynamic flexible pouch that actively responds to battery expansion and contraction. The flexible material and design allow the pouch to dynamically adjust its volume and shape, maintaining contact with the battery surfaces while accommodating dimensional changes
2Stability of the object's composition
If pressure is applied uniformly to the battery packaging, then structural stability is achieved, but uneven pressure distribution damages the solid-state electrolyte during expansion and contraction
Solution Approach 1:
The patent applies different structural characteristics to different parts of the packaging. The pouch body provides conformal support around the battery, while flexible tabs extend from specific locations to distribute pressure locally. This localized design ensures pressure is evenly distributed across the battery surfaces without concentrating stress at specific points that could damage the solid-state electrolyte
3Reliability
If the battery is sealed in a rigid container, then protection from external damage is provided, but the solid-state electrolyte is vulnerable to cracking from internal pressure changes during operation
Solution Approach 1:
The flexible pouch structure acts as a protective shell that can absorb and distribute internal pressure changes during battery operation. Unlike rigid containers that transmit pressure directly to the battery, the flexible material deforms with pressure changes, protecting the solid-state electrolyte from cracking while still providing external damage protection
Solution Approach 2:
The pouch design incorporates flexible material that acts as a cushion between the battery and external environment. This cushioning effect prepares the battery for pressure changes by providing a compliant interface that absorbs stress before it reaches the solid-state electrolyte, preventing cracking before it occurs
Data Source
AI summary
An electrochemical stack assembly includes a laminated pouch surrounding a frame which encloses solid-state electrochemical cells and electrochemical stacks. In some embodiments, an electrochemical stack assembly includes one or more electrochemical cells, each electrochemical cell comprising a solid-state electrolyte to form at least one electrochemical stack with two major surfaces and four minor surfaces; a frame surrounding the at least one electrochemical stack with space between the frame and each of the four minor surfaces; and a laminated pouch surrounding the frame and the at least one electrochemical stack, the laminated pouch in contact with one or both of the major surfaces. In some embodiments, the frame comprises a tray. In some embodiments, the electrochemical stack assembly comprises two trays, each with an electrochemical stack comprising an electrochemical cell, the cell comprising a solid-state electrolyte.