Author Update (9/6/18): See Tom's analysis on safety and quality of Chinese EV batteries in the Wall Street Journal article (8/29/18) published by Mr. Trefor Moss.
Historically, US and European automakers have dominated plug-in EV hybrid (PEV) and battery electric vehicle (BEV) sales worldwide. However, with increasing amounts of Chinese government subsidies to curb air pollution, a strong domestic infrastructure, and a diverse supply-chain base, China has now emerged as the world leader in PEV/BEV sales. According to Frost & Sullivan’s recently released “Global Electric Vehicle Market Outlook, 2018” report, China led worldwide 2017 new EV sales with an astounding 50% market share outpacing their closest competitors (European EV manufacturers) by over 20%. With the recent announcement by Tesla to build a lithium-ion battery (LIB) gigafactory and open EV manufacturing facilities in China, the current global forecast calls for these EV market trends to favor China for at least the next 5-10 years.
Effect of Government Subsidies on Worldwide EV Leadership
More significantly is how the Chinese government is incentivizing domestic EV sales. The recent International Energy Agency report on the 2018 global EV market describes the New Energy Vehicle (NEV) government mandate process for China-based EV manufacturers to “earn” NEV credits based on vehicle range and energy efficiency ratings. Further to these mandates, the national Electric Vehicle Subsidy Program grants subsidies for consumer purchase of EV’s based on vehicle range (km), energy efficiency (kW-hr), and battery pack specific energy (Wh/kg). As such, more credits are allocated for battery technologies with higher energy densities and vehicles with higher efficiency. These new Chinese EV market policies are driving LIB manufacturers to focus on technologies which drive innovation into new design approaches to maximize LIB specific energy. However, the EV engineering community has long recognized that higher LIB specific energy benefits EV range but can also increase the severity and consequences of an energetic LIB safety incident.
Innovating Safe Design into Today’s LIB Market – 2nd Annual IBSCC
In response to needs for increased EV battery safety, the 2nd International Battery Safety Conference in China (IBSCC) was held in downtown Beijing, China , 8-10 June. The IBSCC forum was co-sponsored by the Dept. Of Automotive Engineering at Tsinghua University and Thermal Hazard Technology (UK) to bring government policy makers, R&D institutions, and academicians together to discuss all aspects of LIB safety for EV applications. During the two-day conference, over 25 technical talks ranging from LIB safety design, advanced materials, new LIB standards, safety testing protocols, and novel thermal management technologies were presented.
My invited talk titled, “Effect of Lithium Battery Design Architecture on Safety Testing Protocols”, was kindly introduced by Professor Li Wang (Institute of Nuclear and New Energy Technology, Tsinghua University; Pictured w/T.P. Barrera) who chaired a session on how to more effectively solve LIB safety problems. Prior to my 30-min talk, I was coached to “talk slowly” as my presentation would be translated live in Chinese to the over 200 attendees. My talk emphasized the importance of safety by design via attention to cell packaging strategies, materials selection approaches, and implementation of perceptive safety test procedures.
Other key presentations included topics concerning new developments in LIB safety via novel electrolyte formulations (Nat’l Univ. of Tainan, Shanghai Jiao Tong Univ., and Nat’l Univ. of Singapore); LIB safety and reliability analyses (Tsinghua Univ.); thermal runaway (TR) early warning techniques (Yantai Chunway New Energy Technology Co.); and thermal analyses studies using accelerated rate calorimetric methods (Hydro-Quebec and Nat’l Univ. of Singapore). One of China’s largest LIB manufacturers, Tianjin Lishen Battery Co., discussed their latest research on high-ratio power batteries and safety technology assessments. Dr. W. Fang (China Automotive Technology and Research Ctr, Tiajin) presented results from a detailed study on TR trigger methods for safety evaluations of traction LIB applications. In this work, it was stated that experimental methods utilizing in-situ cell-level implantation methods were not suitable for third-party (battery cell OEM’s) implementation. As a result, penetration and heat-to-vent trigger techniques for large-cell based LIB testing was advocated.
The Evolving Value Proposition: LIB Specific Energy vs. Safety Margins
It is evident that rapid introduction of new developments and innovation into the next generation of EV LIB design is at the forefront of R&D investments in China. However, many conference presenters cautioned against sacrificing LIB safety margins in the pursuit of lucrative government subsidies for higher LIB specific energy targets. The balance to achieve an optimal mix between LIB cost, specific energy, and safety is not isolated to the EV marketplace. Adjacent markets such as electric bicycles, consumer electronics, power tool, medical, and industrial applications worldwide are subject to a similar trade space at different thresholds of compliance.
The value of battery safety forums and conferences lies in the ability of participants to collaborate and partner new LIB designs with end-to-end cost-effective safety design solutions which meet customer requirements across an evolving landscape of operational environments. As users of these technologies, rest assured that the right technical focus is being invested today for implementing safer and more reliable LIB energy storage solutions into future applications. Stay tuned.