The Real Story Behind Electric Bike Battery Fires

Good battery hygiene

Is not this.

When we buy a car, there are certain things we know we need to do to take care of it. We change the oil, wash it, buy new tires when the old ones are worn. Well e-bikes are no different and there are steps we can take to make sure our e-bike’s battery lasts as long as possible.

In our conversations with industry experts, we received a number of suggestions for how to care for an e-bike’s battery and have assembled those into a checklist of best practices.

Replacing an older battery

Lithium-ion batteries supplied with e-bikes are generally considered to have a lifespan of four to five years. That means riders who purchased their e-bikes as recently as 2019 may be nearing the life cycle of their battery’s life.

There are a number of clues that it may be time to replace an e-bike’s battery. Based on guidance from Ed Benjamin, Levi Conlow, Larry Pizzi and Tom Sweeney, we’ve assembled a checklist for riders to run through in order to judge if it’s time to replace the battery.

It’s time to replace your battery if:

Any one of these signs provides sufficient cause to replace the battery. Multiple signs aren’t necessary, but more than one makes replacement more urgent.

When replacing a battery, the old battery needs to be recycled. This step is easy. Simply contact Call2Recycle. They are endorsed by People for Bikes and will be able to help someone dispose of their old battery responsibly.

Purchase a replacement battery only from the original manufacturer

Buying AAA batteries for a TV remote can feel like shopping for a car. There are a multitude of brands with varying capacities, not to mention the opportunity to purchase rechargeable batteries. The myriad choices can be frustrating.

The situation is far simpler when it comes to replacing an e-bike’s battery. Even though batteries can and will vary in capacity, physical size, housing and style of mount, there is an easy solution to all those variables. Go to the e-bike manufacturer for the replacement.

For owners of e-bikes with internal batteries, due to the way the battery fits in the frame, there may be no other option than the e-bike manufacturer.

When we spoke to industry experts, their advice uniformly began with buying a battery from the bike manufacturer. That’s the best way to make sure that one apple is replaced by another apple. Most manufacturers offer replacement batteries in the accessories section of their website. Several manufacturers told us that if an e-bike owner doesn’t see the battery for their model on the company’s website to contact customer service to see if they might have replacement batteries available.

If for some reason a battery isn’t available from the manufacturer, a replacement battery may still be easy to source. Many e-bike retailers will stock batteries from brands such as Bosch and Shimano. If they don’t have the battery in stock, they should be able to order it.

For riders who don’t have a relationship with a local retailer, external batteries like those made by Bosch and Shimano can be ordered online. Before ordering, it’s important to know the battery’s capacity (watt/hours) and voltage. It’s important to match those details exactly.

Another tip from our industry experts was not to shop by price. As Alta’s Pizzi said, “If the price seems too good to be true, it’s because it is.”

Is lithium-ion the future for e-bike batteries?

As we saw earlier, e-bikes are possible thanks to lithium-ion batteries. Even if lithium-ion technology wasn’t inherently flammable, the industry would still have plenty of incentive to look for better battery technologies. If battery makers could create a 720Wh e-bike battery that weighed 3 lbs. instead of 6 lbs., they would.

There are several other battery technologies that e-bike makers could consider for powering e-bikes. Some of them are more promising than others.

One of those alternates is lithium-iron-phosphate composition. This is the technology used in Tesla car batteries. This technology is touted as safer than lithium-ion—it’s easy to find media reports and marketing materials that say it won’t burn. And while it is safer, it’s not foolproof; there are plenty of accounts of Tesla batteries burning.

The big plus for lithium-iron-phosphate (LiFeP04 or LFP) batteries is their lifecycle. They typically last four or five times as long as lithium-ion batteries. Their temperature operating range is also greater than with lithium-ion; they can operate from -20 F to 140 F.

Unfortunately, the pluses end there. Because there aren’t many producers of LFP batteries, they are more expensive than lithium-ion on a per watt/hour basis. The bigger issue is that their energy density is lower than found in lithium-ion batteries. As we mentioned before, most lithium-ion batteries fall in a specific-energy range of 150-200Wh/Kg (the range is greater than that, but that’s where the bulk of today’s batteries fall). LFP batteries fall in a range of 90-120Wh/Kg, which means that an LFP battery will weigh at least 25 percent more than a comparable lithium-ion battery.

More promising is a variation on lithium-ion technology known as solid-state. With this technology, the flammable liquid electrolyte is replaced with a solid. The most obvious advantage of this technology is that it is much less likely to experience thermal runaway and catch fire. Operating temperatures are said to be 20-30 percent lower than with lithium-ion.

Solid-state batteries promise a number of other performance improvements. Energy density will be higher. QingTao Energy is producing a solid-state battery with a specific energy of 368Wh/Kg. Charging is reported to be much faster as well; there are reports of solid-state batteries reaching 80 percent of total charge in less than 15 minutes. The life cycle of the battery will also be greater.

Unfortunately, this technology, while not still in its infancy, has yet to emerge from the bleeding edge. Very few manufacturers make these and none of them have scaled production to the point where they might meet the demands for a consumer product.

Oh, and did we mention? Solid-state batteries are hella expensive.

Consumer safety

When asked about how the e-bike industry will evolve to better protect e-bike owners, Sean Lupton, EBC’s CEO, said, “We need oversight in the US. We’re glad to see the CPSC getting involved.”

He acknowledged that the CPSC can be, like any large government agency, slow to move, but that doesn’t trouble him. He pointed to how insurance rates for manufacturers serve as an incentive to produce quality products.

“Insurance companies are becoming more familiar with e-bike risk,” Lupton said. “Insurance companies have seen the aftermath. They are far more selective about who gets competitive rates. You’ve got to have a good track record.”

Companies with shoddy products will begin to face hurdles, he observed. “Landlords [for commercial real estate] are looking into the safety of battery tech. You won’t be able to sign a lease without insurance. And to get insurance the batteries will have to be approved.”

In short, he says, insurance companies will fulfill the enforcement role.

Hurdles for the e-bike industry

Every time there is a news report that an e-bike’s battery caught fire, that story hurts the reputation of e-bikes as a whole. Even if the product in question wasn’t an e-bike, the fact that the non-endemic media (TV news, newspapers, etc.) often reports the story using the word “e-bike,” it undermines trust for e-bikes as a category.

Lectric’s Conlow says that infrastructure needs to catch up with the industry and riders.

“I think the biggest changes to e-bike batteries in the future will come on the heels of legislation and infrastructure changes. So much of what we need to keep this industry growing is centered around infrastructure support. Imagine e-bike charging stations being used as frequently as Tesla superchargers. Legislation will help drive this new industry forward. For so long there have been no guidelines for e-bike safety.”

As an industry, we have two educational fronts to address, both of which we’ve tackled in this feature. The first is at the point of purchase: When purchasing an e-bike, verify that the e-bike’s electronics have been UL certified, and if the entire system hasn’t been certified, then at least make sure that the battery is UL certified. The perception problem we outlined above will make it increasingly important for e-bike makers to publicize that their e-bikes are UL certified, which is to say, it will become easier to find this information on an e-bike maker’s website.

The second point of education that we have a responsibility to impart to consumers is how to properly care for their e-bike as a whole and their e-bike’s battery specifically. It’s not hard to properly charge and protect an e-bike’s battery, but e-bikes can’t be left outside in the elements the way ordinary bikes often are. Refer back to our section on good battery hygiene that breaks down best practices that will allow you to keep your e-bike’s battery in good working order for years to come.

That there is any ongoing debate in the industry regarding whether we require manufacturers to adhere to UL 2849 (the whole system) vs. UL 2271 (battery alone) is difficult to understand. It’s hard to say if requiring all e-mobility products to adhere to UL 2271 would have prevented all of the fatalities that have occurred, but judging from video of some of the fires (and explosions) that have taken place, it is safe to say there would have been less loss of life.

Electric Bike Report believes it is in the best practice of e-bike manufacturers to adopt UL standards and certify all of their products. We also urge consumers to realize this is a process that will require time and money on the behalf of manufacturers, and to not write-off a product that hasn’t yet become UL-listed. If you see an e-bike you’d like to buy, but don’t see the UL standard being discussed, reach out to the brand and learn where they’re at in the process. Most of them we talk with are seeking UL approval.