You’ll note the word “relatively” in each of these, since there’s still always room for improvement, and lithium batteries aren’t without their drawbacks either. Despite rapid advancement in recent decades, they remain expensive, do degrade over time and usage cycles, and still don’t have energy density even close to the same weight in fossil fuels (hence cars use absolutely huge batteries weighing hundreds of kilos just to match the range of a car with a small fuel tank).
They can also be thermally unstable if incorrectly charged or damaged, and there are still environmental question marks over the mining, processing, and manufacturing of lithium and other metals used in batteries – though as ever, this must be weighed against the impact of fossil fuel production and use, which is hardly squeaky-clean itself.
Solid state battery technology
That’s where solid state battery technology comes in. These batteries are once again the same as any other in principle, but use a solid state electrolyte rather than the usual solvent or gel. Current technology remains focused on lithium, so the solid electrolyte can, in theory, be any material that allows lithium ions to pass through, causing the required chemical changes to the anode and cathode. Battery companies are exploring everything from metals, through ceramics, to special types of glass to act as the solid electrolyte.
Solid state batteries are already in use in some small consumer devices, as well as medical implants, but scaling them up has so far proven very difficult. Difficult tends to mean costly, and given that batteries are already expensive for their energy density, it’s why we’ve not even seen the technology in everyday devices like smartphones just yet – technology giant Samsung only expects to release its first solid state smartwatch in 2026, let alone a phone or laptop, to give you an idea of the timeline.
Why do solid state batteries matter for electric vehicles?
The primary advantages of solid-state batteries are energy density, greater resistance to changes in temperature, and safety. So you can see instantly why car manufacturers are clambering over each other to bring a solid state battery electric vehicle to market.
