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October 08, 2020   •   6 minute read

Safety Considerations for Lithium-Ion Test Chambers

Battery, testing, AES Insights

Battery Test Chamber

The lithium-ion battery has changed the world since it emerged, commercially, in the early 1990s. It has directly influenced the rise of portable handheld devices while also opening the possibilities for better electric vehicles, drones, and military and defense uses, and led to renewable energy options.

Today, even more lithium-based designs continue to emerge. These innovations wouldn’t be possible without countless hours dedicated to rigorous testing during research and development (R&D) and production. It’s a naturally dangerous process completed in extreme conditions.

Product mishaps highlight potential disasters. Think of the failure of Samsung Galaxy Note 7 or hoverboards that destroyed people’s property. Such incidents reinforce the importance of safe and thorough battery testing.

That starts with having best safety practices established and implemented in your labs: alarms, non-sparking materials, and a reduction in static electricity.

Then, when researching new battery test chambers, work with a manufacturer that can help you meet standards—safely. These are some considerations that will ensure quality testing and keep your employees and property safe.


Safety Features of Battery Test Chambers

The standards to which you’re testing determine your test chamber needs. Having said that, standards carry more importance as it pertains to lithium-ion batteries. Companies literally test to failure during R&D and prototyping, and during production when doing batch, lot, or unit testing to push the limits of the battery. In each scenario, the test chamber needs to sustain events without risking the safety of the users or the lab as a whole.

Just as laboratories have safety features, test chambers for battery testing are designed to isolate and mitigate propagating incidents—limiting flames to the affected cell or single tray, for example, as opposed to the entire chamber—rather than containing events that reach extremes. They’ll save you a quick move to grab the fire extinguisher or a call to the fire department and help you avoid permanent damage.

These may be some of the safety features you should consider adding to your test chamber:

Severity Level Description Criteria for Severity Classification & Effects Recommended Safety Features by Severity
0 No Effect No effect. No loss of functionality. Standard chamber features are effective
1 Reversible Loss of Function No defect; no leakage; no venting, fire, or flame; no rupture; no explosion; no exothermic reaction or thermal runaway. Cell reversibly damaged. Repair of protection device needed. Standard chamber features are effective
2 Irreversible Defect/Damage No leakage; no venting, fire, or flame; no rupture; no explosion; no exothermic reaction or thermal runaway. Cell irreversibly damaged. Repair needed. Standard chamber features are effective
3 Leakage
Δ mass <50%
No venting, fire, or flame*; no rupture; no explosion. Weight loss <50% of electrolyte weight (electrolyte = solvent + salt). ALARM: Light tower and audible warning; product overheat protector with sensor

CONTAINMENT: Product drip tray

DOOR: Electromagnetic door lock; solenoid door interlock

GAS: Pressure relief valve during an event; pressure equalization valve (one way valve allowing equalization of pressure between chamber workspace and atmospheric pressure)

4 Venting
Δ mass >=50%
No fire or flame*; no rupture; no explosion. Weight loss ≥50% of electrolyte weight (electrolyte = solvent + salt). SEVERITY LEVEL 3 SAFETY FEATURES PLUS:

CONTAINMENT: Drip tray and reinforced floor; LN2 test article cooling plate

DOOR: Reinforced door latch

EXHAUST: Pressure release port; reversible pressure relief flap; pressure relief system release port and two low flow release

SEALED: Port restraint (stops silicone port cover from popping off); cable port plug restraint (per port, max 6"); drain; motor port; pressure reinforced interior liner and intrinsic barriers; window gasket

5 Fire or Flame No rupture; no explosion (i.e., no flying parts). SEVERITY LEVEL 4 SAFETY FEATURES PLUS: 

EXHAUST: Burst disc/rupture disc; blow out port

FIRE: “Detect-a-fire” system, FM200 suppression system; detection via temperature measurement; suppression system; detection via temperature measurement; protection measured by carbon monoxide

GAS MONITORING: Gas monitor and alarm (single, double, triple gas detection)

PURGE: Continuous inert gas purge (inert/ zero O2 environment); continuous N2 or Ar gas purge (permanent inert gas environment); N2 or CO2 gas purge (permanent inert gas environment)

SPARK RESISTANT INTERIOR: Temperature limited sheath heaters; lights; barriers on sensors; non-sparking fans; sheath heaters; blowers aluminum

6 Rupture No explosion, but flying parts of the active mass. SEVERITY LEVEL 5 SAFETY FEATURES PLUS:

DOOR: Reinforced door; reinforced door hinges

EXHAUST: Burst disc; rupture disc; blow out port

SPARK RESISTANT INTERIOR: Sheath heaters; temperature limited sheath heaters; lights; barriers on sensors; non-sparking fans; interior (this would include all of this); blowers aluminum

SEALED: Remote refrigeration using a portable conditioning unit

7 Explosion Explosion (i.e., disintegration of the cell) SEVERITY LEVEL 6 SAFETY FEATURES

Advanced hardware and software (i.e. AESONE CONNECT, which comes standard on AES models and can be retrofitted on most machines, regardless of manufacturer) also makes remote monitoring of your test chamber from anywhere possible, and, if need be, you can shut down tests as they’re ongoing.

All the safety features work in concert, limiting risk, and triggering responses to events that change based on the nature of the event. Spend time discussing these safety features with your manufacturer as you go through the purchasing process.


Other Safety Considerations

As much as the safety features of the test chamber matter, they can be compromised by poor education and maintenance. Employees who will use the test chamber should be fully informed on everything from proper operations to incident response. Human error leads to accidents, and while it can’t be eliminated, it can be minimized. For instance, a well-designed battery testing fixture (such as AES’s ATP series) limits waste, maximizes efficiency, and is easy to operate—users can safely swap in battery cells without jeopardizing testing results.

You should also couple any purchase of a test chamber with a service plan. Quarterly and yearly maintenance will ensure the long term operational life of your test chamber and enable experts to address smaller issues, such as replacing hinges that show signs of corrosion, before they become big expensive ones.

Working with lithium-ion batteries takes responsibility, and you’ll need to dedicate serious time and resources to conduct tests safely. The payoff, however, can change your industry, if not the world at large.


Associated Environmental Systems has a full line of test chambers that can be customized and fit with fixtures for the purpose of testing lithium-ion batteries. Contact us to find out more today.



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Buyer's Checklist