All-solid-state batteries have been widely regarded as the "ultimate solution" for power batteries by both industry and consumers, but their safety profile may be more complex than imagined. At the 2026 China Automotive Forum, FAW Group chief scientist Wang Deping issued a sober warning: once thermal runaway occurs in all-solid-state batteries, the consequences can be extremely severe. Academician Ouyang Minggao of the Chinese Academy of Engineering went further, telling consumers there is no need to wait for all-solid-state batteries. Japan's JISC released JIS C 8905-2 in May 2026, introducing mandatory thermal runaway propagation testing for solid-state batteries, while IEC 63254 entered CDV voting in April. Meanwhile, not a single vehicle claiming to use "solid-state batteries" in the 2026 market is actually "all-solid-state."
The Deified "Ultimate Battery": A Collective Consumer Illusion
"I'll wait a bit longer. Once all-solid-state batteries hit the road, I'll switch cars."
This has been the common rationale among many internal combustion engine owners over the past two years when considering the switch to electric vehicles. In their view, all-solid-state batteries simultaneously address the three biggest anxieties of EV ownership — fear of fire, limited range, and slow charging. However, at the July 2026 China Automotive Forum, FAW Group chief scientist Wang Deping poured cold water on this enthusiasm: "Once thermal runaway occurs in all-solid-state batteries, the damage is extreme."
Ouyang Minggao, an academician at the Chinese Academy of Engineering, was even more blunt, telling consumers directly: "There's no need to wait for all-solid-state batteries."
Why would top industry experts express reservations about a technology elevated to mythical status? The answer lies in the details of materials science.
The Safety Truth About All-Solid-State Batteries: Not Foolproof
All-solid-state batteries are coveted because they replace flammable liquid electrolytes with non-combustible solid electrolytes, theoretically eliminating the risks of combustion and leakage. But this simplified narrative overlooks several critical issues:
Issue 1: The Type of Solid Electrolyte Determines the Safety Boundary
The most closely watched solid-state battery technology route is the sulfide-based system. While sulfide solid electrolytes excel in ionic conductivity and interface contact, they harbor serious risks under high-voltage and high-temperature conditions:
- Potential release of flammable sulfur gases (S) and toxic hydrogen sulfide (H₂S)
- These gases can react violently with lithium metal anodes, triggering thermal chain reactions and secondary combustion
- Reactions may even form lithium radicals, producing explosive phenomena and vivid magenta flames
In contrast, oxide-based solid electrolytes (such as LLZO) demonstrate significantly higher thermal stability, with no thermal runaway observed in ARC tests.
| Solid Electrolyte Type | Thermal Stability | Primary Risk | Representative Materials |
|---|---|---|---|
| Sulfide | Medium | High-temperature release of flammable/toxic gases, violent reaction with lithium | Li₃PS₄, Li₇P₃S₁₁ |
| Oxide | High | Interfacial reaction with molten lithium | LLZO, LATP |
| Polymer | Low | Direct combustion at high temperatures | PEO-based electrolytes |
Issue 2: Risks of High-Energy-Density Electrode Materials Remain Unresolved
The root cause of thermal runaway lies in the inherent reactivity of electrode materials at elevated temperatures:
- Cathodes can release active oxygen
- Anodes (especially lithium metal) are highly reductive
- When both meet at high temperatures, they can trigger chain exothermic reactions, potentially self-igniting or exploding without external fire sources
In other words, even if the electrolyte itself is non-flammable, the "powder keg" of electrode materials still exists.
Issue 3: "Solid-State Batteries" in 2026 Are Not Truly All-Solid
A shocking yet little-known fact: As of 2026, not a single mass-production vehicle claiming to be equipped with "solid-state batteries" actually uses a truly "all-solid-state" battery.
These batteries mostly fall into two categories:
- Semi-solid-state batteries: Still retain some liquid electrolyte and separators
- Gel-state batteries: Use gel electrolytes as partial replacements for liquid components
Essentially, they represent incremental improvements on traditional lithium batteries rather than revolutionary replacements. Marketing claims by brands such as SAIC MG and GAC Aion, while not entirely false, carry a degree of misleading simplification.
Global Standards Accelerate: The Turning Point from Concept to Regulation
Faced with the uncertainty surrounding solid-state battery safety, global standardization bodies are accelerating their efforts.
On May 9, 2026, the Japanese Industrial Standards Committee (JISC) officially published JIS C 8905-2:2026, the world's first mandatory safety standard for solid-state battery systems. Core requirements include:
- Multi-point nail penetration combined with high-speed infrared thermal imaging (≥1000 fps) for thermal runaway propagation testing
- Strict pass/fail threshold: no propagation beyond the triggered module within 5 minutes
- Explicitly positioned as more stringent than UN GTR 20
On April 29, 2026, the International Electrotechnical Commission (IEC) launched the CDV (Committee Draft for Vote) stage for IEC 63254:2026, the first internationally coordinated standard specifically defining thermal runaway propagation testing methods for solid-state battery systems. Proposed by China's CESI with technical contributions from CATL, it received formal support from U.S., Japanese, and Korean national committees.
The emergence of these standards signals that solid-state battery safety assessment is being upgraded from a "reliability metric" to a "core functional safety attribute" — analogous to the ASIL-rated logic of ISO 26262.
Implications for Consumers: No Need to Wait
All-solid-state batteries undoubtedly represent an important development direction for power battery technology, but their commercialization timeline may be more conservative than industry claims suggest.
Research from leading battery company ProLogium further reveals the truth that "solid-state does not equal safe." In its high-temperature combustion tests:
- Sulfide solid electrolytes emitted vivid magenta flames under intense flame — a warning sign of lithium metal combustion reactions
- Solid polymer electrolytes ignited directly with intense flames
- Only oxide all-ceramic materials and superfluidized all-inorganic solid electrolytes remained flameless throughout the entire test
ProLogium's proposed "Dual Safety Architecture" — all-ceramic separator + superfluidized all-inorganic solid electrolyte + ASM active safety mechanism — represents the industry's latest understanding of what constitutes a "truly safe solid-state battery."
For consumers in cold-climate regions such as Central Asia and Russia, the theoretical advantages of all-solid-state batteries in low-temperature performance are certainly appealing. However, considering their mass-production timeline, actual costs, and the fact that current semi-solid and advanced liquid-electrolyte solutions already satisfy the vast majority of use cases, waiting for the "ultimate solution" may not be the most rational choice. Vehicles equipped with second-generation Blade batteries, CATL's Shenxing batteries, and other advanced liquid-based solutions already deliver commendable levels of safety, range, and charging speed.
Progress in power battery technology is incremental rather than leapfrogging. Rather than chasing the "ultimate solution" in marketing narratives, consumers would be better served by focusing on the actual performance of currently mass-produced technologies. For more technical insights, visit EX1000.COM.
