What are the EV battery safety guidelines?

EV battery safety guidelines are important and extensive. They relate to all aspects of battery use, including performance when exposed to mechanical, electrical and thermal abuse, discharging and charging, and even transportation of the batteries to the factory for installation into the EV. Safety standards have been developed for EV battery packs and for electric vehicle service equipment (EVSE) like chargers. There’s a complex thicket of standards governing EVs. This FAQ provides the briefest of overviews.

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 & security
Charging connectors
Charger topologies
Charging related communications

Figure 1. 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 the propulsion of 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 the design, manufacture, and testing of lithium-ion batteries used in scooters, e-bikes, and other small platforms.
UL 2580 Batteries for Use in Electric Vehicles including automobiles.
UL 2054 and UL 1642 – UL 1642 applies to Li-ion cells while 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 thicket of EV battery safety standards arises from the inherent complexity of Li-ion cells and EV battery packs. It starts with the chemistry, design and packaging of individual cells. Includes safety devices like short circuit protection and battery disconnect devices. The battery management (BMS) hardware and software must be robust. The mechanical design of the modules and overall battery pack must include effective thermal management and mechanical protection from crashes (Figure 2).

Figure 2. EV battery safety standards are complex because EV battery systems are complex (Image: RISE Research Institute of Sweden).

Simplification may be coming
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. The goal of the activity is to converge and simplify the regulatory requirements related to EV battery safety.

NHTSA chaired the development of the initial United Nations (UN) Global Technical Regulation (GTR) for electric vehicle safety, which was 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