I've recently learned that lithium-ion batteries might be a triple threat - Borgia batteries - cherished by eco-royalty, poisonous in the extreme, and explosive enough to wreak havoc in a $25 million laboratory that was built to safely manage battery explosions.
Is it a battery or a WMD?
On April 11th five employees of the advanced battery laboratory at the General Motors (GM) Technical Center in Warren, Michigan were hurt when extreme testing of a prototype lithium-ion battery pack from A123 Systems (AONE) released chemical gases that exploded inside a testing chamber. Four were treated at the scene and one was taken to a local hospital. The injuries were not life threatening.
About 1,100 employees who work in the Warren facility were evacuated while a HAZMAT team spent four hours taking air samples inside and outside the building. While most of the evacuees were able to return to work, it's unclear how long it will take to repair about $5 million of damage to the battery laboratory and resume operations.
GM quickly advised the media that the incident didn't involve a battery for the GM Volt and technically there was no battery explosion at all. Engineers were simply conducting extreme overcharge tests on a prototype battery and it failed, which is exactly what you'd expect.
Or is it?
The fact that there was a battery failure and vented gases ignited doesn't surprise me. The fact that the explosion was violent enough to cause major structural damage to a purpose-built facility that was designed to safely manage the occasional battery explosion is very troubling. The chemical composition of the gas that allegedly caused the explosion is a nightmare. The terrifying aspect is that these issues are being ignored, or at least swept under the rug, to protect the tarnished image of GM's Volt.
On Friday the 13th, Torque News reported:
The battery involved in the Wednesday morning explosion didn't actually explode but rather gases created in the testing chamber ignited and caused the massive explosion. During the extreme testing process, hydrogen sulfide gas collected in the testing area and when that cloud of gas ignited - we had the massive explosion that injured five and did significant damage to the Alternative Energy Center testing area including blowing out windows and at least one 8" thick door. Afterwards, the reports indicate that the battery pack itself was still intact.
It may just be my lawyer's fascination with words and sentence structure, but the second sentence of that paragraph sure sounds like an unattributed direct quote from somebody in the know at GM.
I'm not a chemist, but I have substantial oil and gas experience including three years as legal counsel for Boots & Coots, the largest oil field disaster response firm in the world. Because of that experience I know that hydrogen sulfide gas (H2S) is:
- The reason rotten eggs stink;
- Explosive at concentrations of 43,000 to 460,000 PPM; and
- One of the deadliest poisons known to man.
In the US, Occupational Safety and Health Regulations prohibit exposure to H2S concentrations above 100 PPM without a full facepiece pressure demand self-contained breathing apparatus.
A Wikipedia search shows that an H2S concentration of 150 PPM paralyzes the olfactory nerve, killing the sense of smell; 800 PPM is the lethal concentration for 50% of humans with five minutes of exposure; and concentrations over 1,000 PPM can cause immediate respiratory arrest after a single breath.
That makes H2S sudden death by poisoning at 2.3% of the concentration required for an explosion.
If a comparable failure occurred in a moving car, the driver would be incapacitated in seconds while his vehicle careened into a crowded latte bar before exploding.
I know there's nothing inherently dangerous in the anode and cathode materials for today's advanced lithium-ion batteries. In fact I was surprised by the reports that a lithium-ion battery could generate enough H2S gas to cause an explosion. When I started to ask questions, however, I learned that any number of electrolyte additives, separators, binders, fillers and ancillary cell materials could release highly toxic fumes from a failing cell or battery pack.
The active materials may be wonderful in their own right, but everything that goes into a cell must be carefully evaluated for its capacity to chemically interact with other cell materials and pose a serious threat to human health and safety.
We know the process failed at least once.
GM's "industrial accident" may be a one-off oddity if it was testing an exotic lithium-sulfur battery or something else that's radically different from conventional lithium-ion batteries. It may also be just the tip of an iceberg, the first example of unintended interactions between cell components that can render large format lithium-ion batteries too dangerous for use in passenger vehicles or other enclosed spaces.
100 years ago the Titanic was heralded as an engineering marvel until a completely unexpected turn of events in April 1912 forced engineers to question their basic assumptions. I believe the GM explosion should at least force some soul searching.
For four years I've heard nothing but safety talk from lithium-ion battery manufacturers, ideologues, politicians and would-be end users. This is the first report I've seen that threatens to burst the bubble. If H2S gas was generated in GM's advanced battery laboratory we need to know how much H2S gas was generated, how it was generated and how long the process took. We also need to know to a certainty whether similar problems might exist in large format lithium-ion batteries from other manufacturers. I understand that every battery manufacturer wants to keep its secret sauce recipe proprietary, but there comes a time when customer safety has to take precedence over competitive advantage.
I'm the first to admit profound confusion over the facts that have been reported so far. But there seems to be a consensus that a poisonous gas was generated by a failing battery, concentrations rose to explosive levels in the testing chamber, and the resulting explosion caused major structural damage to a facility that was built in 2009 and designed to withstand catastrophic battery failures.
Under the circumstances, I'm convinced that somebody who doesn't have a political, ideological or economic interest in the safety of lithium-ion batteries needs to get on the ball and conduct a comprehensive independent investigation to find out exactly what happened and whether comparable risks exist in the battery packs used by Fisker Motors, Ford (F), Tesla Motors (TSLA), Nissan (NSANY.PK), Toyota (TM) and others. I can only hope that an upcoming NHTSA technical symposium with battery manufacturers and automakers will mark the beginning of more rigorous regulatory oversight.
Borgia battery? Inaccurate descriptions from reporters? Prototype testing of a truly unique battery chemistry? Or simply a conventional automotive grade lithium-ion battery that was pushed beyond design limits and failed spectacularly? The difference has to be understood before we go much further.
This article was first published in the Spring 2012 issue of Batteries International Magazine and I'd like to thank editor Mike Halls and cartoonist Jan Darasz for their contributions.