FAQ #391
Module Structure Assessed As Columns

Last Updated On 10/14/2025 05:40:22 PM by

cyaeger

Question
How does the SES evaluate module structures against the requirement for 40g acceleration without allowing cell crush?
Answer
The SES will create a test load based on the mass of one module * acceleration * number of modules in a row.
For example, a tractive battery that is 4 modules wide and 2 modules long will have the mass * acceleration force multiplied by 4x laterally, and 2x longitudinally.

The SES is asking about the structure of a single module.
- removed from the tractive battery container
- aligned lat/long/vert as it is in the car (don't worry about single digit differences in angle)

The job of the container is to enclose each module in its own (six sided) box.
Any contribution of the container walls is not included to the evaluation.

Structural cross sections are taken with all cells, wiring, cooling, etc. removed.
And furthermore, treating hole patterns as one large opening.
The front view cross section carries longitudinal load, the side view cross section carries lateral load, the top view cross section carries vertical load.

Just like in your statics class:
A column is continuous in area and continuous along its normal.
If there are multiple separate cross sectional areas, select only the smallest for area and moment of inertia.
Take the minimum cross section, ignoring areas with thicker cross sections.

It is also reasonable to ignore the smallest column(s), and not include the smallest cross section(s) when counting the number of separate cross sectional areas.
For example, if there are 5 areas in cross section, and one is tiny, you may enter 4 as the number of columns, and select the area and moment of inertia for the smallest of the other 4 cross sections.

Please review the attached file.
No Attachments
Rule Numbers
2025:F.10.3.1