31 Aug 23

Will solid-state batteries end range anxiety?

Decades of hard work has gone into improving lithium-ion (li-ion) battery technology. While performance has improved and cost is going down, the advances have not managed to eliminate range anxiety. Will solid-state batteries be able to do that? 

Especially prevalent among 'new' electric vehicle (EV) drivers, range anxiety is a problem with many causes. These include the glaring lack of public charging infrastructure, and the underwhelming performance of current li-ion battery technology. Price is also a factor: why switch to electric if that comes with range anxiety and a higher sticker price? 

According to the International Energy Association, the global average for a new battery-electric vehicle in 2021 was just over $36,000 - down 7% over 2020. The price for a new plug-in hybrid electric vehicle (PHEV) remained stable at $51,000. Despite the influx of lower-priced Chinese EV models, the volume-weighted average price (VWAP) of EVs is projected to be around $52,800 for the whole of 2023, says Statista. 

A large part of the price of an EV is the battery. Could a different technology offer improvements in both price and range? Cue solid-state batteries (SSBs), and their cousin, semi-solid-state batteries (SSSBs). 

What is a solid-state battery?

A lithium battery consists of a cathode and anode, separated by a liquid electrolyte, allowing electrons to pass through it, thus allowing energy generation for EVs. Compared to li-ion batteries, an SSB uses a solid electrolyte, which also has the role of a separator. SSBs offer improved stability with a solid structure and much better safety thanks to maintaining their form even when damaged. SSBs have critical differences compared to li-ion batteries: 

  • Use thin layers of solid electrolytes carrying lithium ions 
  • No risk of explosion, thus reducing the safety materials needed
  • Enhanced use of space thanks to less materials
  • Composing higher energy density battery pack without using more space 
  • Solid electrolyte in the battery ensures performance under low temperatures

Source: Flashbattery

The life cycle of SSBs is also much longer, with some SSBs showing the potential of sustaining 90% of capacity after 5,000 cycles, according to Topspeed (for the conventional li-ion, the life span is between 2,000-3,000 cycles, but lithium iron phosphate batteries, LiFePO4 or LFP, take this up to 4,000). 

According to John B. Goodenough, the co-developer of li-ion battery technology, and researcher Maria H. Braga, 'glass solid-state batteries' can offer three times the energy density by using an alkali-metal anode (lithium, sodium or potassium) and a longer life cycle. Additionally, an SSB using glass electrolytes can perform in temperatures as low as -20°C. 

Used in various devices such as smart watches and pacemakers, SSBs have required a thorough process to become ready for the EV industry. SSBs have an inevitable importance for EVs, prepared to kick open a new era in the industry. Most importantly, the emergence of SSBs will signal the definitve end of internal combustion engines (ICEs), expected to become useless when li-ion and SSB batteries become widely adapted, predictably in the early 2030s. 

SSBs will significantly increase the range of EVs, offering double the mileage with almost half the price compared to li-ion batteries. With many OEMs interested in the technology, the average range of an EV is expected to reach up to 1,000-1,200 km and will be able to charge up in just 10 minutes, according to Toyota. 

Who is working on SSBs? 

Unsurprisingly, almost all major automakers are interested in new-generation batteries, and some are already working heavily on SSBs. 

  • Toyota is working on SSBs with Panasonic, aiming to start using the technology by 2027, providing a range up to 900 miles (1,440 km). The two hold the most patents in SSBs, Toyota having over 1,330 and Panasonic 445. 
  • Renault has partnered with Airbus to develop SSBs, aiming to start manufacturing by 2030. The French auto giant expects to double the range of Megane E-Tech 280-mile (450 km). 
  • Chinese EV maker NIO adopted an SSB strategy in 2021. Its subsidiary, WeLion, delivered the first SSBs this summer, with 150-kWh SSBs to power NIO ET7. Another model, ES6, is predicted to reach the 930 km range with the same battery. 
  • Nissan plans to power the legendary Leaf with SSBs, aiming to start mass production by 2028.
  • According to Reuters, Ford, BMW, and Hyundai have invested in U.S.-based startup Solid Power. 
  • Volkswagen is backing another U.S. startup, QuantumScape, to make SSBs available for EVs. The company has agreements with six automakers. QuantumScape's SSB prototype can retain over 80% of its capacity after 800 cycles. 
  • Automotive Cells, a venture between Mercedes-Benz, Stellantis, and TotalEnergies, is developing SSBs with Taiwanese ProLogium Technology.

Toyota's SSB prototype. Source: Toyota

Already a competitor: The semi-solid battery 

Along with SSBs, semi-solid state battery technology has been developed for a while, led by M24. A semi-solid battery has one electrode with a liquid electrolyte and one without. Small, stable, and safer semi-solid batteries also have higher energy density and are cheaper than li-ion batteries. From drones to smart wearable devices, semi-solid state batteries offer a wide range of areas to be used, including EVs. 

In 2015, 24M announced a new semi-solid lithium battery cell design that would lower costs by around 50%. Four years later, 24M told Dual Electrolyte tech, presented as a layer of improvement to be added to LFP for storage and NMC batteries for mobility applications. In 2022, 24M said it had simplified the li-ion battery design, reducing the need for inactive materials by up to 80%, costs 40% and providing li-ion cells with an energy density between 400-500 Wh/kg, specifically made for the aviation industry. 24M's solution refers to other markets, including EVs and energy storage. 

Source: Takomabattery

What are other known developments? 

  • US-based Factorial, backed by Stellantis, Mercedes-Benz and Hyundai, revealed a 100 Ah battery featuring a polymer-based solid electrolyte at CES 2023. The battery offers up to 50% energy density and is the first to receive the UN 38.3 safety standard. 

Source: Factorial

  • CATL, the Chinese battery giant, announced a condensed battery in April with an energy density of 500 Wh/kg. Using a polymer gel-like electrolyte is another semi-solid battery and will be mass-produced by the end of 2023. 

Image: CATL

  • Another semi-solid state battery, produced by NIO's WeLion, represents a 150-kWh battery pack weighing 575 kg, including 384 units of cells. Thus reaching an energy density of 260.9 Wh/kg. 

Image: NIO

How does 2030 look for SSBs? 

The li-ion usage among battery-powered vehicles is over 95%, and li-ion nickel-cobalt-manganese (NCM) batteries are highly preferred thanks to their well-balanced energy density. At the current improvement rate, NCM li-ion batteries are expected to achieve $100/kWh at the cell level. With the arrival of SSBs, the EV prices could be lowered by 25-50%, offering long-range EVs with a price tag of around $ 20,000 to $ 30,000. 

According to Research and Markets, the costly development process may vary in the range of $400-$800 kWh by 2026. Nevertheless, over 60% of the vehicles sold globally will be EVs, with stronger batteries and widespread charging networks, says the IEA, signalling a solid adoption for SSBs in the early 2030s. The main obstacles to overcome in the SSB development will be poor stability and high surface resistance. 

The main image is courtesy of Shutterstock, 2192930967.

Authored by: Mufit Yilmaz Gokmen