China’s National Automotive Standardization Technical Committee has released its inaugural national standard for solid-state batteries in electric vehicles for public consultation, marking a significant step toward commercializing the technology. Published on December 30, the document titled “Solid-State Battery for Electric Vehicle – Part 1: Terms and Classification” lays out formal definitions, classifications, and coding systems to guide the emerging industry.
This first installment in a planned four-part series addresses terminology and battery categorization, with future parts expected to cover performance benchmarks, safety requirements, and lifespan criteria. A separate technical specification for solid-state electrolytes is also under development.
Key to the standard is its detailed classification framework. Batteries are divided by ion transfer mechanism into three categories: liquid, hybrid solid-liquid, and solid-state. The term “semi-solid-state” has been eliminated. Solid-state batteries are further classified by electrolyte composition—sulfide, oxide, polymer, halide, or composite—by conducting ion (lithium-ion or sodium-ion), and by application focus (high-energy or high-power).
The draft introduces a more stringent verification criterion than earlier industry guidelines. To qualify as a solid-state battery, products must exhibit a weight loss rate no greater than 0.5% under specified vacuum drying conditions, tightening the limit from 1% in a team standard issued earlier this year by the China Society of Automotive Engineers. The committee noted that some solid electrolyte materials may decompose during testing, leading to minor weight loss, and industry input indicated that genuine solid-state batteries consistently achieve sub-0.5% loss rates.
1. Primary Classification — By Ion Transfer Mechanism
| Class | Description |
|---|---|
| Liquid | Conventional batteries using liquid electrolytes |
| Hybrid solid-liquid | Batteries containing both liquid and solid electrolyte phases |
| Solid-state | Batteries using only solid electrolytes |
Note: The term “semi-solid-state” is explicitly removed from the standard.
2. Secondary Classification — Solid-State Batteries Only
a) By Electrolyte Material Type
| Electrolyte Type | Description |
|---|---|
| Sulfide-based | Thiophosphate and related sulfide electrolytes |
| Oxide-based | Garnet, perovskite and other oxide electrolytes |
| Polymer-based | Polymer electrolytes such as PEO systems |
| Halide-based | Lithium or sodium halide electrolytes |
| Composite | Combinations of multiple electrolyte types |
b) By Conducting Ion
| Ion Type | Meaning |
|---|---|
| Lithium-ion (Li⁺) | Standard chemistry for EV solid-state systems |
| Sodium-ion (Na⁺) | Alternative chemistry for cost and resource flexibility |
c) By Application Focus
| Focus | Intended Use |
|---|---|
| High-energy | Maximizing energy density and driving range |
| High-power | Maximizing power output and fast-charge capability |
3. Verification Criterion — Qualification as Solid-State
| Criterion | Requirement |
|---|---|
| Weight loss rate | ≤ 0.5% under specified vacuum drying conditions |
China’s move to establish formal standards for solid-state batteries addresses a current gap, as no automotive-grade norms exist domestically or internationally. Observers expect the standard to clarify terminology, harmonize technical requirements, and support coordination across the supply chain as manufacturers advance toward large-scale production and application of solid-state battery systems.
Source: CarNewsChina
