BYD Vice President Stella Li has said the company plans to have its first model with solid-state battery technology ready in 2027. She made the remarks in an interview with Carwow.es published in September. Still, announcing that a next-generation battery will go into a vehicle does not mean it will go on sale or that mass production will succeed. Getting a battery into a car is one thing; building it in volume at consistent quality is something else entirely.
What the first-model announcement leaves undecided
Li said BYD is ahead in solid-state battery technology and commercialization, and that it will have its first model with the technology ready next year to demonstrate this. She added that the company is studying not only battery chemistry but also manufacturing capacity and equipment design. These are a BYD executive's development plans and self-assessment; no third party has confirmed that BYD leads the race.
The remarks give no model name or price. They do not say in which countries or when customers will be able to buy the car, and they do not amount to a product announcement with figures for driving range or charging time. A promise to "have a model ready" is meaningful, but it is too early to read it as a commitment to deliver cars to consumers.
The quoted remarks also use the general term "solid-state battery." That phrase alone does not settle the electrolyte composition of the upcoming model. The plan draws attention alongside all-solid-state battery development, but the specifications of the battery actually used will have to wait until the vehicle is presented.
BYD's 2027 plan had been reported before. What is new is the executive's statement that the first model will be shown. The question to watch now moves from the performance of cells in the lab to whether the battery works as an in-vehicle system. Putting a battery in a car is not the end point of development but the entrance to a new set of tests.
On the road, the question is whether solid materials stay in contact
Toyota and Idemitsu describe one obstacle to the durability of all-solid-state batteries: cracks that form between the electrodes and the solid electrolyte during repeated charging and discharging. The electrolyte is the material through which ions move inside a battery. When a liquid is replaced with a solid, maintaining contact between materials becomes important for keeping performance up over a long period.
The sulfide-based solid electrolyte the two companies are developing is soft and adheres easily to other materials. When announcing their partnership in 2023, Toyota said that developing a material resistant to cracking had given it a path to achieving both performance and durability. However, this describes the two companies' materials development; it does not show that BYD uses the same material or solution.
BMW has already published a concrete example of in-vehicle testing. In May 2025, it announced that it was operating a BMW i7 test vehicle fitted with large all-solid-state cells from Solid Power around Munich. This test, which uses a sulfide-based solid electrolyte, examines how to manage cell expansion, how to control pressure during operation, and how to adjust temperature conditions.
These test items show well why evaluating all-solid-state batteries takes more than material performance. Once cells, the basic unit of a battery, are assembled and built into a vehicle pack, mechanisms to hold them in place and manage their temperature are also needed. Without considering the weight and structure that come with them, a car's driving range cannot be inferred from the energy density of a single cell.
BMW itself says further development is needed to turn this into a competitive energy storage system. Running a car on the road is a different stage from having a finished product. For BYD's model as well, it will be easier to judge how far the technology has progressed if the company shows the conditions under which performance was measured and how the battery changed after repeated use.
Same year, 2027, but different stages for each company
In its official announcement for InterBattery 2026, Samsung SDI set a goal of starting mass production of all-solid-state batteries in the second half of 2027. It also lists expansion into applications such as humanoid robots, which is different from announcing a particular EV launch. Toyota and Idemitsu, meanwhile, separate the market introduction of vehicles equipped with the batteries from full-scale mass production afterward.
BMW's road tests, Toyota and Idemitsu's market-introduction target, and Samsung SDI's battery mass-production target represent different stages of development, so the year alone cannot establish who is ahead.
The table below sorts the announcements we checked as of September 15, 2026, by what each company is doing or completing. It is not a performance ranking of plans announced at different times.
| Company / date of announcement | Subject and what was announced | Stage reached / status |
|---|---|---|
| BMW and Solid Power (May 2025) | Operating a BMW i7 fitted with all-solid-state cells | Road testing under way. Further development needed for commercialization |
| Toyota and Idemitsu (October 2023) | Market introduction of vehicles with all-solid-state batteries in 2027–2028 | Market-introduction target. Full-scale mass production to be considered based on that track record |
| Idemitsu (January 2026) | Large pilot facility for solid electrolyte to be completed during 2027 | Construction of materials production facility has begun. Completion is a target |
| Samsung SDI (March 2026) | Mass production of all-solid-state batteries in the second half of 2027 | Battery mass-production target. Plans to expand into robot applications as well |
The differences in the table are not simply a matter of how cautious each company is. Completing a materials production facility, mass-producing batteries, and bringing a car to market are separate jobs. The shared year "2027" alone does not align production scale or the time when the cars can be bought.
The same applies when evaluating BYD's announcement: it is necessary to track separately whether the first model is ready, whether performance has been demonstrated on the road, and whether supply to the general public is possible. By the yardstick of road testing, BMW already has a published track record, and by the yardstick of mass-production targets, Samsung SDI has named a specific time. To check Li's claim of being "ahead," one must first define what it is ahead in.
When the technology spreads depends on stable materials supply
In January 2026, Idemitsu announced that it had begun building a large pilot facility to manufacture solid electrolyte. It aims to complete the facility at its Chiba site during 2027, with an expected production capacity of several hundred tons per year. The material produced is to be used in the all-solid-state batteries for EVs that Toyota is developing.
Idemitsu already makes the material at a small demonstration facility and will scale up production based on that experience. The "several hundred tons" here refers to the amount of solid electrolyte, not the output of finished batteries or the number of EVs. Nor does the completion of the facility mean that vehicles carrying the batteries will ship at the same scale.
This plan is a useful reference for assessing mass-production readiness, because it shows not only the completion year but also what the facility makes, what stage of demonstration it has gone through, and which product the material will be used in. It is a case from a supply chain separate from BYD's, but it illustrates concretely that spreading the battery requires connecting materials production all the way to the vehicle.
Li's mention of manufacturing capacity and equipment design alongside materials chemistry overlaps with this issue. The ability to make a good cell and the ability to keep supplying cells of the same quality have to be verified separately. The success of a first model alone cannot be taken to resolve questions of price and supply volume.
When BYD presents its model in 2027, driving range and charging time figures should come with test temperatures and usage conditions. If the in-vehicle mechanisms that support durability and the equipment that supports stable production become concrete, solid-state batteries will move from a development plan people hope for to something that can inform the choice of which EV to buy.