Technology

A solid-state battery is a rechargeable energy storage system similar in overall structure and operation to the more familiar lithium-ion battery. The two differ in that a lithium-ion battery contains a liquid electrolyte while a solid-state battery—as its name suggests—features a solid one. This allows solid-state batteries to be lighter, have more energy density, offer more range, and recharge faster. The challenge to making solid-state batteries viable is developing technology commonly used in small devices and applying it to large-scale applications like electric vehicles (EVs).

The first-ever mass-produced electric vehicle was the EV1, which General Motors launched in 1996. A dedicated EV built from the ground up, the 2-seat coupe had a range of 78 miles, accelerated to 50 mph in 6.3 seconds, and took more than 5 hours to charge fully. A lead-acid battery powered it.

When the second-generation EV1 rolled out a mere three years later, its power source switched to a nickel-metal hydride battery pack and driving range nearly doubled to 142 miles. Just as the EV1 was being phased out, Tesla Motors entered the automotive sphere with its Tesla Roadster, the first production battery-electric vehicle to utilize lithium-ion batteries. As the saying goes, the rest is history.

Lithium-ion batteries have become the standard for powering many devices, from consumer electronics like cellphones and laptops to mobility and transportation like bicycles and automobiles.

Unlike the lead-acid and nickel-metal hydride batteries of yore, lithium-ion batteries are constructed with a liquid electrolyte to manage the flow of energy between the cathode and anode. The benefits of a lithium-ion battery include longer battery life, better performance in varying temperatures, recyclable components, and higher energy density. Energy density is the amount of energy a battery can store per unit weight. Simply put, the higher the density, the higher the power output.

Despite its many benefits, there are drawbacks to lithium-ion batteries. Although lighter than older battery technologies, its liquid insides still make lithium-ions quite heavy. They also perform better when in stackable packs, which adds even more weight. Additionally, the electrolytes are flammable, can be unstable in extreme temperatures, and lead to explosions or fires if damaged or improperly charged. There is no shortage of news reports covering everything from cellphones to airplanes catching fire due to battery issues.

By doing away with the sloshing, flammable liquid electrolyte, solid-state batteries are, by default, more stable and compact. The solid electrolyte can be composed of any number of everyday materials, like ceramics and glass.

Solid-state batteries have been used in small devices like pacemakers as well as RFID and wearable devices for years. Having fewer bits and pieces means fewer things can go wrong. In addition to improved safety, size, and stability, solid-state batteries in EVs would also offer faster charging times, more travel range, and even greater energy density.

Solid-state batteries can reach an 80-percent charge within 15 minutes and incur less strain after multiple charging cycles. A lithium-ion battery will begin to degrade and lose power capacity after 1,000 cycles. On the other hand, a solid-state battery will maintain 90 percent of its capacity after 5,000 cycles.

With a lithium metal anode, solid-state battery technology can provide higher energy densities. They avoid using hazardous or harmful materials used in industrial batteries. Solid-state batteries rely on a solid electrolyte, which is more stable, less flammable, and safer. Since it doesn’t have a risk of explosion or fire, there is no need to have components for safety, thus saving more space.