- Large-scale adoption of all-solid-state batteries may not happen until after 2030, BYD's battery business CTO said.
- After a certain level of scale of use, the cost of solid-state ternary batteries will theoretically reach a level comparable to liquid ternary batteries, he said.

BYD (HKG: 1211, OTCMKTS: BYDDY) expects to begin "demonstration use" of all-solid-state batteries around 2027, the company's battery business CTO Sun Huajun told a forum today.
True large-scale adoption of all-solid-state batteries may not be realized until after 2030, Sun said at the forum on all-solid-state batteries, according to a video replay seen by CnEVPost.
Looking at the industry as a whole, different players are making about the similar progress, Sun added.
BYD is the world's largest new energy vehicle (NEV) maker and the second-largest maker of power batteries.
In 2024, BYD's power battery installed capacity was 153.7 GWh, with a 17.2 percent global share behind CATL's (SHE: 300750) 37.9 percent.
In April 2024, CATL's chief scientist Wu Kai told a battery industry event that the company aimed to produce all-solid-state batteries in 2027 in small volumes, but high-volume production would still face problems including cost.
Liquid lithium batteries could reach an energy density of 350 Wh/kg, but it's difficult to continue to improve, while all-solid-state batteries are expected to reach an energy density of 500 Wh/kg, Wu said at the time.
In November last year, local media LatePost reported that CATL, which was focusing on the sulfide route for all-solid-state batteries, had entered the trial production stage of 20 Ah samples.
In today's speech, Sun mentioned that BYD's material selection for solid-state batteries is also based on sulfide electrolytes, mainly from cost and process stability considerations.
The other two main technology routes for all-solid-state batteries are the oxide route and the polymer route. Last April, Chinese solid-state battery startup Talent New Energy, which chose the oxide route, said it had successfully made solid-state battery cells with an energy density of 720 Wh/kg.
BYD initiated research and development on all-solid-state batteries in 2013, when it was mainly exploring technology routes and materials, Sun said.
By 2016, BYD initiated the verification of the technical feasibility of all-solid-state batteries, and the prototypes at that time were mainly soft-pack batteries with a very small capacity of less than 1 Ah, Sun said in his speech.
By 2023, BYD had begun to validate the feasibility of industrializing all-solid-state batteries, designing cell systems, materials and various technologies, according to Sun.
By 2024, BYD has already seen trial products of solid-state battery cells with a single cell capacity of 20 Ah and 60 Ah roll off the production line, according to Sun.
He believes that cost will not be an issue for solid-state batteries in the long run.
In the sulfide route for solid-state batteries, it is still the ternary materials, mainly nickel and cobalt, that have the biggest impact on cost, according to Sun.
The reason the cost of sulfide electrolytes is very high right now is mainly because the volume is so low, Sun said. "It doesn't really make a lot of sense to talk about cost in the absence of volume."
After a certain level of scale of use, the cost of solid-state ternary batteries will theoretically reach a level comparable to that of liquid ternary batteries, Sun said.
BYD chief scientist expects solid-state batteries to be widely used in 5 years' time