Battery Test Engineering

I worked at an energy startup manufacturing lithium ion batteries for electric vehicles and energy grid applications. I was part of the test and data team, on a team of five responsible for the testing and data management of all prototype batteries that were produced in the Cambridge office. The work we did often was for clients or projects that have yet to be released so all accompanying images are sample images of 24m Technologies products.

Tested prototype battery cells using Newware and Maccor battery cycle testers and desired test conditions
Aided in the formation and degas process of new battery cells
Conveyed battery test results to battery scientists and engineering team leads using Tableau data visualization
Maintained a database of 500+ batteries simultaneously on test using Maccor’s MIMS software
Installed and performed maintenance on battery test incubators and other lab equipment

Core Responsibilities

A sample 24m battery after the formation process.

Battery Pressurizing Project

Challenge:

Design a fixture that is able to keep large format, multi-layer battery cells under constant pressure for cycle life testing

Constraints:

The fixture must fully enclose the large format 24m battery cell
The fixture must utilize existing parts we had on hand in the lab
The fixture must hold the cells under a constant pressure of 130 psi
The fixture must be rapidly manufactured in the 24m machine shop

Process:

I measured and modeled existing battery fixtures for the smaller format cells in SolidWorks
I increased the size of these fixtures to accommodate for the large format cell size
I exported the SolidWorks model to CNC instructions and had the parts machined in the on site machine shop
I pressurized the plates using different combinations of springs we had on hand in the lab, and measured the internal pressure on the cell using pressure sensors
After the pressure level was verified, our team was able to use these fixtures to test the cells at the desired temperature and pressure

Small format cell pressure fixtures

A large format 24m battery cell

Results:

The test fixtures worked, we machined more of them to support multiple large format test initiatives
I learned how to pressurize batteries under specified conditions
I was able to practice CAD and CAM as well as using a CNC mill
I modified an existing fixture to be able to accommodate the next iteration of our product and allow for it to integrate with our existing prototyping and test fixtures