Electric Vehicle Battery Testing Trends & Challenges

Crystal Instruments provides    complete electric battery testing solutions

Crystal Instruments provides complete electric battery testing solutions

The market demand for electric vehicles continues to grow rapidly around the world. Avicenne Energy reports car manufacturers around the world will invest billions of dollars in electric vehicles by the year 2030 (1). Volkswagen alone is reportedly planning to spend approximately $40 billion on electric versions of their vehicles, which total to over 300 different models around the world (1). Among domestic car manufacturers, Ford is expecting to launch 40 new electric and hybrid models around the world with a planned investment of $11 billion and General Motors pledges to sell 20 all-electric vehicles by 2025 (1). In Asia, Toyota, Honda, and Nissan are all pursuing aggressive plans to launch diverse new selections of electric vehicle models. Chinese automakers are also committing to significant investments into the development of electric vehicles.

The global trends driving the demand for electric vehicles includes the challenges of existing mobility and energy solutions coping with significant increases in population and city growth. Countries leading in the investment of electric vehicles include Germany, China, the USA, Japan, South Korea, and France (1). However, when examining the percentages of lithium ion cell production around the world, China leads the way with a 60% share of global production capacity. South Korea and Japan follow modestly with 15% and 17% shares of global production capacities each (1). 

Electric vehicles are propelled by large electric motors which are powered through a rechargeable onboard battery system (2). The rechargeable electrical storage system (RESS) in electric vehicles comprises of a complex formation of battery packs (2). The controlled release of the battery’s energy provides useful electrical power whereas the uncontrolled release of this energy can result in dangerous safety hazards.

Lithium ion batteries remain as the dominant choice for electric vehicle production. The following are examples of lithium ion battery types used in the market today.  

  • Lithium Cobalt Oxide (LiCoO2) Batteries
    The Tesla Roadster and Smart Fortwo electric drive (ED) use Lithium cobalt batteries. These batteries feature a high energy density and long-life cycle but suffer from poor thermal stability and requires monitoring during operation to ensure safety (3).
  • Lithium Manganese Oxide (LiMn2O4)
    Multiple electric vehicle manufacturers use li-manganese batteries blended with lithium manganese cobalt oxide (NMC) to improve energy and life span (3).
  • Lithium Iron Phosphate (LiFePO4)
    Lithium Iron Phosphate batteries feature efficient power-to-weight ratios, high safety features and a resistance to thermal runaway (3). These batteries are becoming popular in motorhomes.
  • Lithium Nickel Manganese Cobalt Oxide (Li(NixMnyCo1-x-y)O2)
    Manufacturers including Nissan, Chevy, and BMW utilize these li-ion batteries which combine nickel and manganese, resulting in excellent thermal characteristics (3).
  • Lithium Nickel Cobalt Aluminum Oxide (Li(NixCoyAl1-x-y)O2)
    Tesla is the only known electric vehicle manufacturer that uses Lithium Nickel Cobalt Aluminum Oxide (NCA) batteries (3). These batteries require special monitoring and safety precautions.

Lithium ion batteries face specific challenges, such as thermal runaway, which occurs when battery temperatures increase suddenly and rapidly (2). These sudden increases in temperature can result in fires or even explosions (2). Drivers around the world have reported incidents of lithium-ion batteries sporadically bursting into flames after the impact of an accident (4). The results of thermal runaway can occur hours or even days after the impact event. Thorough and accurate testing is crucial to ensure the safety of drivers.

Battery safety standards and regulations require testing in combined abusive environmental conditions found in actual battery applications. Battery standards for electric vehicles/hybrid-electric vehicles (EV/HEV), 2 and 4-wheeled vehicles, laptops and wearable devices, include, but are not limited to the following:

  • IEC 62660-2:2016 Secondary Lithium-ion Cells for the Propulsion of Electrical Road Vehicles Reliability and Abuse Testing

  • IEC 62113-2:2017 Secondary Cells and Batteries Containing Alkaline or other Non-Acid Electrolytes – Safety Requirements for Portable Sealed Secondary Cells, and for Batteries Made from Them, for Use in Portable Applications.

  • IEC 62660-3:2016 Secondary Lithium-ion Cells for the Propulsion of Electrical Road Vehicles – Safety Requirements

  • SAE J2464:2009 Electric and Hybrid Electric Vehicle Rechargeable Energy Storage System (RESS) Safety and Abuse Testing

  • UN38.3:2015 Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria – Section 38.3 Lithium Batteries

  • BATSO 01 Manual for Evaluation of Energy Systems for Light Electric Vehicle (LEV) – Secondary Lithium Batteries

  • UL 2271 Batteries for Use in Light Electric Vehicle (LEV) Applications

In recognition of the detrimental effects of combinations of temperature, humidity, vibration and input electrical power on electrical and electro-mechanical components with regard to safety, integrity, and performance during ground and flight operations, MIL-STD-810H, has been released with Method 520.5 added to cover the testing of components in combined environments. Testing in combined environments may induce failures that would not be exhibited during individual environment testing. New to this test method is the addition of input electrical power as an environment; to include voltage/frequency variations, and transients (if applicable) which are inherent to the system. While it is virtually impossible to replicate the complex mix of environments which can be seen during transport, storage, operation, and maintenance, the intent is to apply representative combinations of stresses to the device under test to determine performance and capabilities.

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Crystal Instruments provides powerful solutions for combined mechanical, environmental and thermal testing required by a wide range of standards and specifications. The Spider-101 temperature and humidity controller with IEEE time synchronization conveniently controls combined temperature, humidity and vibration testing of batteries, electrical and electro-mechanical components. It is the only controller with the following advantages:

  • One user interface for setting up run schedules for temperature, humidity, vibration, etc.

  • Fully networked allowing users to connect multiple hardware devices through Ethernet which allows one PC to control all devices at the same time

  • Ability to extract battery information through a CAN bus and take various actions including emergency shutdown

  • Access and control with one software application

  • Data acquisition is accurately time-synchronized

  • One combined test report – If test reports are generated separately from several apps, the time clock and schedules will not be coordinated, unlike the integrated test report generated by Crystal Instruments’ EDM THV Software

 References Cited

  1. Pillot, Christophe. “The Rechargeable Battery Market and Main Trends 2018-2030.” Stockage Batterie Conference on May 28, 2019 in Paris, France, Avicenne Energy, 2019.

  2.  Mok, Brian. “Types of Batteries Uses for Electric Vehicles.” Submitted as coursework for PH240, Stanford University, Fall 2016, http://large.stanford.edu/courses/2016/ph240/mok2/

  3.  Miao, Yu, et al. “Current Li-Ion Battery Technologies in Electric Vehicles and Opportunities for Advancements.” Energies, vol. 12, no. 6, 2019, p. 1074., doi:10.3390/en12061074.

  4. Siacon, Aleanna. “Electric Car Batteries Can Catch Fire Days after an Accident.” Chicagotribune.com, Chicago Tribune, 18 Aug. 2019, https://www.chicagotribune.com/autos/sns-auto-electric-car-batteries-can-catch-fire-days-after-an-accident-20190531-story.html.