Geely Auto has publicly questioned the safety of ultra-fast charging, highlighting battery temperature risks in a move widely interpreted as a challenge to BYD’s flash-charging technology. The debate centers on whether pushing battery cells beyond 65°C during charging is safe, as Chinese automakers compete to deliver faster charging speeds.
Geely Cautions Against High Charging Temperatures
On its official WeChat account, Geely Auto (HKEX: 0175) published a post warning that battery cell temperatures above 65°C during charging are ‘not recommended.’ The company referenced China’s national standard GB/T44500-2024, which sets 65°C as the maximum charging temperature for lithium iron phosphate (LFP) power batteries.
While Geely did not mention any competitor by name, the statement is widely seen as a response to BYD’s (HKEX: 1211) aggressive promotion of its second-generation Blade Battery and 1,500-kilowatt flash-charging technology.
Technical Arguments and Industry Reactions
Geely’s post cited Joule’s law, noting that battery heat generation increases exponentially with higher current. The company emphasized that as megawatt-level fast charging becomes more common, battery thermal management faces greater technical challenges.
Geely highlighted that its Shendun Golden Battery, tested by the China Automotive Technology & Research Center, reached a peak temperature of just 64°C during a full megawatt-level charging process. The battery also passed the GB38031-2025 certification, described as the ‘strictest battery safety order in history.’
The controversy intensified after a Chinese battery industry blogger livestreamed a test of BYD’s Fang Cheng Bao Tai 3 on May 6. The test showed the vehicle charging from 9% to 97% in 9 minutes and 9 seconds at 25°C ambient temperature, but with battery temperatures peaking at 76.42°C.
BYD and Industry Responses
Li Yunfei, general manager of BYD’s branding and public relations division, responded on Weibo on May 7, inviting people to test flash charging in extreme heat conditions. The discussion continued as other battery makers weighed in.
At an industry conference on May 17, an executive from Gotion High-tech (SZSE: 002074) stated that the safe operating temperature for LFP batteries is 60°C, and that lithium hexafluorophosphate—making up over 60% of electrolyte costs—begins to decompose at 60°C, with decomposition accelerating at 70°C.
BYD’s chief technology officer for its battery business group, Sun Huajun, addressed the concerns in a May 19 interview. Sun explained that BYD’s Blade Battery uses a symmetrical structure for improved heat dissipation and that the company has optimized the battery’s dimensions for flash charging. Sun argued that industry standards for safe temperatures have evolved and that innovation should continue to push boundaries.
Market Context and Sales Trends
The debate comes amid fierce competition between Geely and BYD. According to the China Passenger Car Association (CPCA), Geely led automaker retail sales in the first five months of 2026 with 848,116 units, a 17.7% year-on-year decline. BYD followed with 766,401 units, down 39.1% year-on-year.
In the new energy vehicle (NEV) segment, BYD remained the leader, while Geely ranked second with 470,396 units. BYD has focused exclusively on NEV models since March 2022, while Geely continues to offer fuel-powered vehicles alongside its NEV lineup.
China’s EV market has seen rapid growth, with domestic EV sales exceeding 11 million vehicles in 2024 and a compound annual growth rate of 23.66% expected through 2030.
Why this matters
The ongoing debate over battery charging temperatures highlights the technical and safety challenges facing ultra-fast charging in electric vehicles. As automakers race to reduce charging times, ensuring battery safety and longevity remains a critical concern.
With China’s EV market expanding rapidly and battery standards evolving, the outcome of this discussion could influence future regulations and consumer trust in high-speed charging technologies.
What this means for buyers
Consumers considering ultra-fast charging EVs should pay attention to battery safety standards and the technical claims made by manufacturers. While faster charging is appealing, understanding how it may impact battery health and warranty coverage is essential.
Buyers are encouraged to monitor updates from both automakers and regulatory bodies as the industry continues to debate and refine best practices for high-speed charging.
Key Specs
- Maximum recommended charging temperature (LFP batteries): 65°C (~149°F)
- Geely Shendun Golden Battery peak temperature (tested): 64°C (~147°F)
- BYD Fang Cheng Bao Tai 3 peak charging temperature (tested): 76.42°C (~169.6°F)
- BYD Fang Cheng Bao Tai 3 charging time (9% to 97%): 9 minutes 9 seconds
- Geely retail sales (Jan-May 2026): 848,116 units
- BYD retail sales (Jan-May 2026): 766,401 units
- Geely NEV sales (Jan-May 2026): 470,396 units
- China domestic EV sales (2024): 11 million units
Source
Images sourced from: com.au, hibridosyelectricos.com
