Checklist Before Sending Li-Ion Cells for Failure Analysis

Before sending lithium-ion cells for failure analysis, record the cell’s history, photograph and measure it, note its state of charge, sort intact from damaged cells, and pack and declare the shipment the way your carrier and the regulations require. Missing history slows the analysis more than anything else, and poor packing can destroy the evidence or make the shipment unsafe. Use the checklist below before anything leaves your site.

This checklist is for quality and R&D engineers, lab managers and researchers sending failed or suspect cells to an outside lab such as our failure analysis lab. It is not dangerous-good advice: your shipper must follow the carrier’s rules and the regulations that apply to your route.

The checklist before sending lithium-ion cells for failure analysis

#	Item	Done?
1	Cell history written up (see template below)
2	Photos from all sides, plus close-ups of any damage
3	Open-circuit voltage measured and recorded, if safe to do so
4	State of charge recorded and agreed with the lab
5	Cell sorted as intact or damaged/defective
6	Terminals protected against short circuit
7	Packaging and labels confirmed with carrier and shipper
8	Lab told what you expect them to find, and what you need answered
9	Reference cell from the same batch included, if available
10	Shipment date agreed so the lab can receive it

 

Record the cell history

The lab cannot see what happened before the cell arrived. Give them the story in writing:

Field	What to write
Cell identity	Maker, model, chemistry, format, batch or serial number
Use history	Cycling profile, number of cycles, rates, voltage limits
Environment	Temperatures, storage time and conditions
Event	What failed, when, how it was noticed (capacity loss, swelling, heat, venting)
Data	Cycler files, impedance, temperature logs
Your hypothesis	What you think happened and what you need confirmed

 

Photograph and measure before packing

Take photos from every side, with a scale, before you touch the cell more than necessary. Note swelling, discolouration, leaks or deformed tabs. If it is safe, measure open-circuit voltage and thickness. Swelling usually means gas inside the cell; our article on the causes of gas generation in lithium batteries explains the common sources.

State of charge: record it, agree it

Do not change the cell’s state just to ship it without talking to the lab first. Charging or discharging a failed cell can change the evidence and can be unsafe. Record the state of charge as received, then agree with the lab and your carrier what is acceptable for shipping.

Damaged or defective cells ship differently

Cells that are swollen, leaking, vented or known to be defective are treated as a separate category from intact cells in transport rules. Road-shipping checklists in Europe, for example, split damaged and defective cells into their own transport cases under ADR. In the US, a report prepared for PHMSA by A-P-T Research in October 2020 studied how defective and damaged charge storage devices should be classified and shipped. It describes thermal runaway as a condition in which heat from a failing cell causes it and surrounding cells to fail, and calls it the most likely lithium-ion failure mechanism to cause problems in transport. The report notes flammable gas from electrolyte breakdown has been shown at temperatures as low as 70 °C, and that the separator melts at around 135 °C. It tested four container designs, without endorsing products. Read the PHMSA report.

For damaged cells, ask your carrier and a trained dangerous-goods shipper which packaging, labels and documents are required before you book anything.

What not to do

• Do not open, puncture or “investigate” the cell yourself before shipping.
• Do not tape over leaks or try to flatten a swollen cell.
• Do not ship damaged cells as if they were intact.
• Do not pack cells loose where terminals can touch metal.
• Do not send cells without a written history and a contact name.

This checklist was prepared by the failure analysis team at Canrd. For more about us, visit Canrd’s homepage.

Frequently asked questions

Should I discharge cells before sending them for failure analysis?

Not without agreement. Changing a failed cell’s state can alter evidence and may be unsafe. Record the state of charge as received, then agree with the lab and your carrier what is acceptable for shipping. Your dangerous-goods shipper has the final say on transport conditions.

How do I ship a swollen or damaged lithium-ion cell?

Treat it as damaged or defective, which is a separate shipping category from intact cells. Isolate it, do not press or tape over it, and ask your carrier and a trained dangerous-goods shipper which packaging, labels and documents are required before booking.

What information does a failure analysis lab need?

The cell’s identity, use history, environment, what failed and when, any cycler or temperature data, photos, and your own hypothesis. A reference cell from the same batch helps too. Complete information lets the lab plan its first non-destructive steps before opening anything.

 

Ready to send? Tell us about the cells first, and we will confirm intake and shipping details: send us your failed cells.