Future-Proof Pouch Cell Design

We encourage solution providers to address the following key areas, divided into initial focus areas for early development and long-term goals for future scalability: 

Initial Focus Areas

1. Leak-Proof Durability & Space Maximization: 

• The primary goal is to ensure that Na-Ion pouch cells can maintain leak-proof integrity during their lifecycle, particularly around the tab areas, which are prone to stress and potential leakage. 
• Solutions should also focus on maximizing space efficiency within the pouch cell design. For example, weld line length should be optimized to prevent energy loss and maintain compactness. 
• The sealing process must endure vacuum conditions of up to 900 mbar for a maximum of 60 seconds and perform consistently despite extreme temperature fluctuations, ranging from -30°C to +60°C. 

2. Material Compatibility: Proposals should align with Na-Ion chemistry and focus on compatible materials, including: 

• Aluminum foils for the pouch. 
• Hard Carbon for the anode. 
• Prussian blue/white analogs for the cathode. 
• EC-PC-DMC electrolyte with 1M NaPF6. 
• Aluminum tabs only for the tab material. 

3. Cell Dimensions: Solutions must ensure compatibility with the following cell dimensions (see visuals in tab “Knowledge Base”) 

• Length: 150 to 400 mm 
• Width: 130 to 180 mm 
• These dimensions allow flexibility for various applications while maintaining compact and efficient designs. 

Longer-Term Goals: 

1. High Current and Overcharge Resistance: 

• As development progresses, solutions should ensure that the cells are designed to handle high current applications and provide overcharge resistance without compromising sealing integrity. 

2. Cost Sensitivity & Scalability: 

• While initial solutions should be feasible, long-term goals should aim for cost-effective production with a Return on Investment (RoI) within 3 years. This includes optimizing the cycle time (3-4 seconds or less) for sealing operations and ensuring the electrolyte filling process is efficient. 

3. Tolerance Range: 

• As solutions advance, they should incorporate defined process parameters that allow immediate identification of acceptable versus non-acceptable components (e.g., through welding parameters or other sealing steps). This approach reduces the need for extensive post-production testing. 

 4. Minimizing Testing & Validation Needs: 

• Long-term solutions should strive to reduce the need for extensive external testing by ensuring reliable and repeatable sealing performance during production, thus cutting down on time and costs associated with validation. E.g. for testing durability under temperature fluctuations, a Thermocycle Test could be used, exposing the pouch cells to repeated cycles of extreme temperatures (e.g., -28°C for 8 hours followed by +66°C for 16 hours, repeated for 7 cycles). Alternative test methods are also welcome to ensure robustness against varying conditions."