Electric vehicle (EV) battery safety guidelines are essential and comprehensive, covering every aspect of battery use. This includes performance when exposed to mechanical, electrical, and thermal abuse, discharging and charging, and even the safe transport of batteries to the factory for installation.
Rigorous standards for EV battery packs and electric vehicle service equipment (EVSE) like chargers have also been developed to ensure safety, with a complex thicket of standards governing EVs. This article provides a brief overview.
In addition to being numerous, EV safety standards vary regionally between Europe, China, Japan, and North America. Figure 1 highlights some of the standards related to EVs from the International Standards Organization (ISO), International Electrotechnical Commission (IEC), SAE International (SAE), and GB/T Chinese national standards, but it’s far from exhaustive.
Four common classifications for EV safety standards are:
- Safety and security
- Charging connectors
- Charger topologies
- Charging related communications
Figure 1. The EV battery safety standards related to charging and chargers. (Image: JT Mobility)
Foundational standards
While the numerous standards illustrated above relate to all aspects of EV battery charging, there are foundational standards specifically for the batteries. Some representative standards include:
- IEC 62133 is a broad standard. It covers various aspects of battery safety, including electrical, mechanical, and chemical safety.
- IEC 62660 series of standards covers secondary lithium-ion cells for propulsion electric road vehicles.
- ISO 12405, Electrically propelled road vehicles, is a test specification for lithium-ion traction battery packs and systems.
- ISO 16750 applies to EV systems and components. It’s focused on potential environmental stresses and test requirements related to specific mounting locations.
- UL 2271 Batteries for Use in Light Electric Vehicles (LEV) covers the safety requirements for designing, manufacturing, and testing lithium-ion batteries used in scooters, e-bikes, and other small platforms.
- UL 2580 Batteries for Use in Electric Vehicles, including automobiles.
- UL 1642 applies to Li-ion cells.
- UL 2054 applies to small battery packs.
- UN/DOT 38.3, Transportation Testing for Lithium Batteries, applies to almost all Li-ion batteries.
Standards complexity arises from battery complexity
The complexity of EV battery safety standards stems from the intricate nature of Li-ion cells and battery packs. These standards encompass everything from the chemistry, design, and packaging of individual cells to crucial safety features like short circuit protection and battery disconnect systems.
A reliable battery management system (BMS) is essential in hardware and software. In contrast, the mechanical design of the modules and overall battery pack must incorporate effective thermal management and protection against crashes (Figure 2).
Figure 2. EV battery safety standards are intricate due to the complexities of battery design, chemistry, and risk management — especially for use in a vehicle. (Image: RISE Research Institute of Sweden).
A simpler way
The US National Highway Traffic Safety Administration (NHTSA) has established its ongoing Battery Safety Initiative for Electric Vehicles to coordinate research and other activities to address safety risks relating to EV batteries. This is a collaborative effort, and the goal of the activity is to converge and simplify the regulatory requirements related to EV battery safety, with the active participation of all stakeholders.
NHTSA chaired the development of the initial United Nations (UN) Global Technical Regulation (GTR) for electric vehicle safety, established under the UN World Forum for the Harmonization of Vehicle Regulations in 2018. Phase 2 is currently underway to develop GTR No. 20 for EV safety. Some of the considerations to be included in GTR No. 20 are issues related to battery thermal runaway, water immersion, and vibration resistance.
Summary
Safety standards for EV batteries are extensive and complex. The large number of standards arises from regional and national differences and from the inherent complexity of the Li-ion battery technology used in the pack. There are nascent efforts underway at the U.N. to simplify global battery safety standards.
References
- Battery Certification and Testing for Automotive and Electric Vehicles, Intertek
- Battery regulations are all about safety, Aved
- Battery Safety Initiative, National Highway Traffic Safety Administration
- Fire Safety of Lithium Ion Batteries in Road Vehicles, RISE Research Institutes of Sweden
- Global Technical Regulation No. 20, Global Technical Regulation on the Electric Vehicle Safety (EVS)¸ United Nations
Filed Under: Batteries, FAQs, Safety and Reliability