Cognition Rack and Fixture System: Test Programme Summary
- Jul 17
- 3 min read
Recently at Cognition our team successfully executed a large-scale cell test programme for a client, utilising 250 test channels to evaluate 370 small format pouch cells.
Martin Browne, Battery Test Engineer
This comprehensive programme, spanning over 660 individual test profiles and including up to 700 cell loading and unloading events, would have traditionally required two to three technicians using standard cell holders. The Cognition rack and fixture system was deployed throughout the project to boost efficiency, minimise labour requirements, and preserve the reliability of the tests.
System Design and Setup
The rack system allowed all cycler and thermocouple channels to be connected externally to the environmental chamber, providing clear channel identification, simplifying the installation and project setup process. Chambers fitted with racks could also be moved between cyclers with minimal downtime, improving scheduling flexibility and equipment utilisation. After installation, channel continuity and thermocouple checks confirmed that all connections were functioning correctly before testing began, helping protect data integrity and reduce setup risk.
Operational Efficiency
Preparing replacement fixtures in a dedicated loading area during active testing enabled swift swap-overs, minimising chamber downtime and maximising overall workflow efficiency. Additionally, this configuration allowed operators to replace isolated cells or smaller clusters without disturbing adjacent setups. The system significantly optimised labour, dropping the staffing requirement from two or three technicians to just a single operator once setup inside the environmental chambers was complete. The loading process involved pre-equipping each fixture with a cell and thermocouple, sliding it into the rack to automatically couple with the rear electrical connector, and completing the attachment of the thermocouple lead.
Thermal chamber with 24 fixtures loaded
To enhance internal organization, short, integrated thermocouple extensions were used to prevent cable clutter and tangling within the chamber. Additionally, prominent front-facing serial number labels on the cells strengthened traceability and reduced the likelihood of tracking or loading errors.
Fixture Flexibility and Compression Control
The fixtures accommodated multiple cell sizes and supported controlled compression testing. An adjustable spring-loaded mechanism allowed the required compression force to be applied consistently to each cell, either by adjusting the spring set point or installing springs with different load characteristics. This flexibility enabled the client’s specified test conditions to be replicated accurately across different cell types, improving consistency, repeatability, and confidence in the test results.
Safety, Reliability, and Throughput
The system proved highly reliable over the six-month test period, with no failures or significant issues reported with the fixtures, racks, or cycler wiring. Our dedicated holders improved safety during handling and transit, while the standardised loading procedure improved setup consistency. For calendar-ageing tests, a complete environmental chamber could be loaded in less than 10 minutes. Across the project, the loading and unloading time was reduced from approximately 6.5 hours using conventional cell holders to just 2 hours with the Cognition rack system, a reduction of almost 70%. Stackable fixtures also improved organisation, airflow, and thermal stability during calendar ageing, while allowing cells to remain mounted in their compression fixtures during storage thus ensuring they were immediately prepared for testing as needed. When used for calendar ageing, the stackable fixtures promoted improved airflow and thermal stability compared with loose cell stacking.
Project Outcomes
By implementing the Cognition rack and fixture system, the project significantly reduced labour requirements, improved chamber utilisation, increased throughput, and maintained high standards of safety, traceability, and test consistency.
Project summary:
370 cells tested
More than 660 individual tests completed
1,820 health checks performed
Almost 97,000 charge/discharge cycles completed
Approximately 1 MWh of energy cycled
The combination of rapid cell changeovers, repeatable fixture setup, external channel connections, and reliable operation enabled the programme to be completed more efficiently and at lower resource demand than would have been possible using conventional cell holders, ensuring the project was a resounding success while cutting the stress in half!