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A Red Flag for Battery Safety

by Ron CoganOctober 9, 2021
Battery safety is a serious concern for makers of electric vehicles today because of potential battery fires. But in earlier years, one of the most serious incidents wasn’t a fire, but a toxic chemical cloud from an EV’s experimental battery.

Automakers, energy interests, and major government-funded efforts have been on the hunt for the ideal battery to power electric cars for decades. It hasn’t been an easy road and remains a challenge even today, as shown by several massive recalls of electric vehicles with batteries that, in rare cases, have suffered spontaneous combustion. Fires aren’t a new thing. During the EV’s drive to market, a small number of battery fires occurred early on, including several in experimental Ford Ecostar electric vehicles powered by sodium-sulfur batteries back in 1994. One battery safety incident that stands out occurred at an electric car race in 1992. Rather than a fire, a race entry running an experimental battery suffered a leak that spewed a toxic vapor cloud that injured racers and race personnel, causing the raceway to be evacuated. Here, we present the following article from the Green Car Journal archives, as it was originally published in June 1992.

Excerpted from June 1992 Issue: It was in the final hours of racing activity at Phoenix International Raceway when the lead car began spewing a reddish-brown vapor trail into turn one, then went into a spin, braking hard.

As the car slowed to a stop, its driver tore at the window’s safety net and dove out of the opening head-first, stumbling, then collapsing as he tried to escape the battery gases that filled his cockpit and the area around the car. Like the driver, James Worden, of the Solectria team (Boston, Mass.), 14 track officials and others who came to his aid would be taken to the hospital to treat breathing difficulties. Worden was admitted in serious condition. Fortunately, all 15 people injured in the accident recovered.

This was the sobering final scene that red-flagged this year’s APS Solar and Electric 500 in Phoenix, Ariz. An important showcase of new and developing electric car technology, the race exemplified new thinking like quick-change battery packs and race-style pit stops under 20 seconds. Many of the cars were substantially faster than just a year ago, and the driving more sophisticated. Products from major sponsors like General Electric, Motorola, Goodyear, and Firestone were used and touted on banners and cars. The event drew a small crowd of enthusiasts and a good showing of research teams from across the U.S. Many were small-time efforts with personal cars converted to electric propulsion. Others were well-financed teams equipped with the latest in electric motors, controllers, and batteries.

It was the experimental battery technology that brought an early end to the Chrysler-Plymouth Electric Stock Car 200. Complexed bromine solution leaked from a dislodged tube in the race car’s pressurized zinc-bromine battery on lap 91, hitting the hot track and creating a toxic cloud near the car and an acrid smell that hung over the infield. The hazardous materials team handling the incident ultimately ordered the raceway evacuated. Although disabled, Worden’s Solectria entry was later declared the winner since he was five laps ahead of the field.

Should this experimental battery have been at the race? Race sanctioning body Solar and Electric Race Association (SERA) regulations specifically cite that “any battery type (except silver-zinc) is generally permitted and any number of batteries may be utilized within the vehicle.” Thus, the prototype zinc-bromine batteries used independently by both the Solectria and Texas A&M entries were allowed. A wide array of other battery technologies, some potentially dangerous, would also be permitted under these rules.

Phillip Eidler of Johnson Controls, supplier of the experimental batteries in the Solectria car, told GCJ that of the battery technologies being pursued, zinc-bromine is one of the safer ones. “What you saw out there was one of the worst incidents, short of crashing into the wall, you’re probably going to see from the battery system.” He also cites that the Johnson Controls battery does not contain pure bromine. “It’s a complexed form, in solution, that doesn’t have near the vapor pressure and evaporation rate of pure bromine,” advises Eidler. Johnson Controls is the largest U.S. manufacturer of lead-acid automotive batteries and the leading supplier to both the original equipment and replacement markets.

Sources at Johnson Controls cite the company is engaged in a cost-shared development contract for the zinc/bromine battery with the U.S, Department of Energy for utility applications. Zinc-bromine is said to have 2-3 times the energy capacity of lead-acid batteries and, according to Johnson Controls’ vice-president of battery research Bill Tiedemann, it’s “one of the most environmentally safe battery technologies available.”

"While experimental technology is critical to the developing EV and alternative fuel vehicle fields, it’s equally critical that safety is addressed as vigorously outside the lab as it is inside. "

A spokesman for principal race sponsor Arizona Public Service (APS) told GCJ that the technologies to be used by race teams will certainly be examined more clearly for safety in coming years. SERA’s Ernie Holden cited that closer scrutiny would be built into the safety inspection process for future races as well. Johnson Controls is also offering to help in any way it can to make the race a safer event. Since assurances from entries using experimental technology cannot serve as the final word on safety, though, it’s obvious that an expert inspection team will be needed to independently perform this task.

This incident should sound a warning signal within the industry. While experimental technology is critical to the developing EV and alternative fuel vehicle fields, it’s equally critical that safety is addressed as vigorously outside the lab as it is inside. This is especially true in the case of public demonstrations of experimental technology. With the upcoming schedule or races, ride-and-drives-, and public demonstrations of electric vehicle technology worldwide, it will be imperative that adequate safety measures are taken. The same holds true for future fleet testing of electric vehicles using potentially hazardous batteries. A catastrophic battery failure on city streets could have wide-ranging consequences.

Experimental technology will continue to be seen in electric car racing, since racing is the proving ground that ultimately benefits the cars that make it to dealer showrooms. But high-risk system components, or even ones protected by redundant safety systems which could still prove deadly in the event of catastrophic failure, might be penciled out in the rule books for safety and liability reasons. This is especially true of those technologies which could injure large numbers of people in a single incident.

What of experimental components, like batteries, which need to be tested during their evolutionary run to market? That’s why the major automakers have proving grounds In their place, smaller R&D firms can rent a track like Phoenix International Raceway or countless others around the world…and do their testing with the stands empty. “It would probably have been much better for us if we would have just ran and ran the car around the track without anybody there,” muses Johnson Controls’ Eidler. “But we’ve done years worth of testing. After that works, where’s the next place you go?” That’s a dilemma that will surely be faced by many R&D efforts in coming years. He adds: “There comes a point where you have to take it out on the road.”

GCJ editors do expect that electric cars will compete in major-league racing alongside conventional gasoline-engine cars. But it seems certain that some important safety checks will have to be in place. Racetracks packed with tens of thousands of spectators are not the venue for volatile technology that could endanger the lives of those who are on hand to root for its success.