Cover The NIO ET7 electric sedan has a range of 1,050 km thanks to its semi-solid-state battery pack (Photo: NIO)
The NIO ET7 electric sedan has a range of 1,050 km thanks to its semi-solid-state battery pack (Photo: NIO)
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Energy-dense solid-state batteries will replace lithium-ion cells in future EVs
A clear advantage of electric vehicles (EV) over internal combustion engine (ICE) vehicles is energy efficiency. An EV has a lower cost per kilometre compared to an ICE vehicle that uses fossil fuels. Compared to gas prices, which are more volatile, the cost of electricity is relatively stable, too.
The rapid pace of technology in the development of EVs has steadily attracted more buyers who are moving away from ICE vehicles. Like any electronic gadget, EVs continue to have more advanced features with every model year.
While the infrastructure for EV charging is more robust in countries such as the United States and China, the rest of the world is still catching up when it comes to the number of charging stations. The deployment of charging stations may be outside the control of EV manufacturers, so they are setting their sights on battery technology to alleviate range anxiety among consumers. Some manufacturers have already introduced five-minute rapid charging, but it seems other improvements are on the horizon.
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How do EV batteries work?
Most current model EVs use high-voltage lithium-ion NCM (nickel cobalt manganese) and NCA (nickel cobalt aluminium) batteries. Lithium-ion batteries are also found in consumer electronics such as smartphones and laptop batteries. The technology behind this battery has been around for almost three decades.
Inside each battery cell are positive (cathode) and negative (anode) electrodes. The lithium ions are found in both the cathode and anode, which are separated by a micro-permeable separator. Both electrodes are immersed in a liquid electrolyte solution where the ions will flow. This flow of ions from the cathode to the anode is what is called a discharge cycle. The discharge flow creates electrical energy for the EV. When the flow of the ions is reversed, it is called the charging cycle. A higher percentage of nickel means the battery has a higher energy density.
In batteries, energy density is commonly stated in watt-hours per kilogram or Wh/kg. The current energy density for lithium-ion NCM/NCA batteries is 150 to 325 Wh/kg. Although there are many things to consider when computing for range in an EV, a typical lithium-ion cell can enable an EV to have a 320 to 540 km range per full charge.
The race for a better battery
Above The Changan VIIA concept car features scissor doors and a convertible roof (Photo: Changan)
The Changan VIIA concept car features scissor doors and a convertible roof (Photo: Changan)
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A solid-state battery gets its name from the material that replaces the liquid electrolyte in a typical lithium ion battery. The solid electrolyte is made of either glass, ceramic or metallic material. The removal of the liquid electrolyte allows the battery to be more densely packed. Solid-state batteries can theoretically have an energy density of 400 to 600 Wh/kg.
Chinese automobile and EV maker Changan has announced that it will roll out prototype vehicles with solid-state batteries at the end of 2025 to early 2026. Mass production of the solid-state battery will begin by 2027. Changan has said that a solid-state battery with a 400 Wh/kg energy density will enable an EV with up to 1,500 km range on a single full charge. Previously, CATL, the world's largest battery manufacturer, announced that it will make solid-state batteries in small batches by 2027. BYD revealed a similar timeline for its solid-state battery rollout.
The future of solid-state battery technology
Above The Golden Shield battery developed by Changan (Photo: Changan)
The Golden Shield battery developed by Changan (Photo: Changan)
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To prepare for the development of solid-state batteries, the Chinese government has instituted the China All-Solid-State Battery Collaborative Innovation Platform (CASIP) in 2024. Members include automotive and battery manufacturing companies such as BYD, NIO, EVE Energy, CALB, Gotion and SVOLT. The consortium’s goal is to make solid-state battery production competitive while establishing a supply chain by 2030.
While the development of solid-state batteries are moving at a rapid clip by industry standards, other car makers have set their timelines that are further along. There are still a lot of technical hurdles to overcome. Toyota has promised to introduce solid-state battery EVs by 2027, with a 2030 target date for mass production. Honda began a test production of solid-state batteries in January this year. Nissan has promised a timeline of early 2029 for its solid-state battery-powered EVs. Hyundai and Kia have pushed back on the launch of solid-state EV batteries by 2030.
Above The NIO ET7 electric sedan has a range of 1,050 km thanks to its semi-solid-state battery pack (Photo: NIO)
The NIO ET7 electric sedan has a range of 1,050 km thanks to its semi-solid-state battery pack (Photo: NIO)
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For the short term, Chinese EV makers such as NIO have released a semi-solid-state battery that can be swapped in their EVs. The battery has a 150 kWh capacity, making it the largest capacity battery pack made in China with the highest energy density of 360 Wh/kg. The battery was tested on a NIO ET7 EV sedan, which travelled over 1,044 km on a single charge.
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