Rapid charge revolution | How solid-state battery tech could be the game-changer for electric bikes

There must be something slightly disheartening about being in the battery development game. For years we all simply accepted the same old alkaline disposable cells and NiCd rechargeables, with short lifespans and tiny outputs, but the arrival of the lithium-ion battery in the 1990s changed all that.

Here was a technology that lasted longer, charged better and was much more energy-dense than its predecessors, and it’s a technology that’s continuously improved since its introduction.

Without li-ion, most of today’s tech – whether it’s the smartphone or the electric motorbike – wouldn’t be viable. But because li-ion tech has improved so rapidly over the past three decades we’re now constantly awaiting the next leap forward.

For many, solid-state batteries represent that step. But what are they, and could they finally offer a petrol rivalling range and recharge performance for the larger-capacity motorcycle industry?

Main benefits of solid state batteries:

• No more liquids: Solid electrolyte replaces the liquid or gel used in a conventional li-ion cell, eliminating the need for a separator to keep the electrodes from shorting.
• Upping the capacity: The idea opens the door to lithium metal anodes that have the potential to give solid-state batteries much higher capacity than current li-ion designs can achieve.
• Safety first: With no flammable liquid electrolyte, solid state batteries can’t leak and are less susceptible to hard to control fire.
• Weight saver: As well as being more compact, solid-state batteries reduce the need for strong protective cases around the batteries, saving more weight and size.
• Faster charge times: Because they tolerate higher temperatures, solid-state batteries can be charged and discharged faster without thermal runaway.

Li-ion is a blanket term covering a whole array of different battery chemistries, but the idea is to have a positive electrode, or cathode, made of a metal oxide or phosphate, and a negative electrode, the anode, that’s normally made of graphite. These sit in a liquid electrolyte made from a solution of lithium salt, and the electrodes are kept apart by a separator that stops the battery from shorting but allows lithium ions to pass between the cathode and anode.

As the battery is charged, ions move from the cathode to the anode, and when it discharges the ions go the other way, causing a chemical reaction that releases a flow of electrons into whatever circuit is connected to the battery.

• Related: Sodium-ion batteries offer safer and cheaper alternative to conventional batteries

Solid-state batteries are a development of the same idea but replace the liquid electrolyte with a solid. That means the batteries are much tougher than existing li-ion designs and the tech opens the door to high-performance lithium metal anodes that can’t survive in liquid electrolytes.

Current liquid electrolytes are usually flammable, compounding the problem of the relatively delicate battery structure because damage can lead to leaks, short-circuits and fire but also requiring battery temperatures to be controlled, limiting how fast they can be charged.

The solution is tough battery cases, which add size and weight to the batteries, and cooling systems for batteries that increase it further.

The appeal is clear, then, and unsurprisingly there’s plenty of interest from car and motorcycle companies, which are already investing heavily in the idea of solid-state batteries.

On two wheels, Honda’s most recent briefing on their electric motorcycle plans said they have an ‘eye toward’ using all-solid-state batteries in the mid- to long-term, and BMW are also investing in the tech for their cars and bikes.

Battery-swapping scooter pioneer Gogoro showed their own prototype solid-state unit back in 2022, and India’s Ola Electric – a scooter maker that last year showed prototypes for a range of large electric motorcycles – recently revealed they are working on their own solid-state battery.

The downside? Large-scale production of viable solid-state batteries is still some way off. Toyota are believed to be leading the race and expect to offer commercial solid-state batteries in cars in 2028, with a 20% increase in range and the ability to charge from 10% to 80% in less than 10 minutes, but most companies, including motorcycle brands, are looking at timescales that don’t see the tech in showrooms until the 2030s.