EV propulsion

Performance and reliability testing

By Philippa Martin-King

At the end of March 2011, the United States President Obama announced new energy security initiatives for making the US more independent of oil. In addition to expanding cleaner sources of electricity, his energy plan contained four major areas for development, one of which was for advanced vehicles.

Lithium-ion battery pack in CalCars' EnergyCS/EDrive converted Prius (Photo: Calcars.org) Lithium-ion battery pack in CalCars' EnergyCS/EDrive converted Prius (Photo: Calcars.org)

"Rising prices at the pump affect everybody – workers and farmers; truck drivers and restaurant owners" stated the White House fact sheet issued the previous day. In paving the way for the vehicles of the future, the US budget includes plans to put 1 million EVs (electric vehicles) on the road by 2015 providing redesigned tax credit for consumers, competitive grants for communities that encourage the adoption of electric vehicles, and funding for R&D to drive innovation in advanced battery technology.

Similarly, Beijing, never a major player the internal-combustion engine market, has ordered its auto industry to move forward in an effort to explore new areas. The Chinese government plans on taking a lead in the EV market with 5 million electric vehicles on the roads by 2020, roughly 35 % of the total world EV market according to HSBC. Present figures for the US and China combined show there are barely 2 million EVs on the roads.

IEC TC responds to global energy moves towards the EV

Responding to global concerns about CO2 reduction and energy security and the turn towards battery, hybrid and plug-in hybrid electric vehicles, one of the TCs (technical committees) of the IEC has already responded with two new International Standards on the high-power and high-energy density traction batteries that will be necessary for the EV of the future to move forward.

Performance and life testing

In December 2010, IEC TC (technical committee) 21: Secondary cells and batteries produced the first edition of IEC 62660-1 that specifies performance and life testing of secondary lithium-ion cells used for propulsion of electric vehicles, including both BEV (battery electric vehicles) and HEV (hybrid electric vehicles).

Lithium-ion batteries are expected to be one of the most promising secondary batteries for the propulsion of electric vehicles. This new publication provides a standard method for testing the performance requirements of lithium-ion batteries for automobile traction lithium-ion cells.

IEC 62660-1 was specifically produced to take into account the present global situation and the diversity of automobile battery packs and systems that exists, each with its own usage specificity. IEC 62660-1 provides test procedures that are sufficiently versatile to be able to obtain the essential characteristics of a range of lithium-ion cells for vehicle propulsion applications in terms of capacity, power density, energy density, storage life and cycle life. On the basis of IEC 62660-1 it will be possible to carry out basic performance and common primary tests of the lithium ion cells in a variety of battery systems and packs for vehicle propulsion applications.

Reliability and abuse testing

The second part in this series of International Standards, IEC 62660-2, also published at the end of 2010, specifies the reliability and abuse testing for lithium-ion cells that are used for EV propulsion both in BEV and HEV. It specifies test procedures and conditions for obtaining the data that is essential for the design of battery systems and packs including mechanical, thermal and electrical tests, charge, overcharge and discharge conditions.

Lithium-ion battery pack in CalCars' EnergyCS/EDrive converted Prius (Photo: Calcars.org) Lithium-ion battery pack in CalCars' EnergyCS/EDrive converted Prius (Photo: Calcars.org)
First Chevrolet Volt lithium-ion battery pack First Chevrolet Volt lithium-ion battery pack
Nissan Leaf runs on a lithium-ion battery Nissan Leaf runs on a lithium-ion battery