The cell versus the system: standardization challenges for electricity storage devices

New types of storage devices such as electric double-layer capacitors (commonly known
as supercapacitors) and high-capacity batteries such as lithium batteries (which can be
designed for either high energy or high power applications) are now appearing on the
market and promise to make a significant contribution to de deployment of performant
electrically propelled vehicles, both battery-electric and hybrid. In urban traffic, due to
their beneficial effect on environment, electric vehicles are an important factor for
improvement of traffic and more particularly for a healthier living environment.
The introduction of such new components creates the necessity for relevant and reliable
standards to assess components' performance and safety. Technical committees within
international standardization bodies such as IEC and ISO have thus increased the
intensity of standardization work on the matter.
As for the electric double-layer capacitors, a new standard is now being developed by
IEC TC69, defining a standard procedure to measure electrical characteristics of the
capacitor. This proposal is now circulating as a CDV.
With regard to lithium batteries however, the situation is more complicated.
Firstly, since the charge and discharge characteristics of batteries in hybrid applications,
where the battery is intended foremostly as power storage, differ strongly from batteryelectric
applications, where the battery acts as energy storage, new test cycles have to
be defined.
Furthermore, battery characteristics, particularly concerning safety, can be regarded
from the viewpoint of the battery or from the viewpoint of the system. The first
approach is the traditional battery cell and module standardization as performed by the
IEC battery committees. The automotive sector however, represented in the relevant ISO
committees, wants to standardize the battery system, as a component of the vehicle
traction system.
As has happened in the past on other electric vehicle related issues, the different
standardization cultures between the two sectors have come to a collision, with several
overlapping and potential conflicting new work items on lithium batteries being
submitted parallely.
High level negotiations have been held to resolve these problems, leading to the
definition of clear scopes for new standards to be drafted on the subject. The system
approach will be developed into the ISO standard, whileas new IEC standards are being
drafted for battery cells and modules. IEC work will take place on two tracks, with the
vehicle batteries, with their particular characteristics and usage cycles, being treated by
IEC TC21/SC21A/TC69 JWG separately from stationary and other general applications
treated by IEC SC21A, allowing the vehicle battery module standards to closely
complement the ISO document on vehicle battery systems. The boundary between the
two documents will be drawn based on the definition of the battery pack and its
associated ancillaries which are part of the vehicle battery system but outside the
battery as such.
The standardization for electricity storage devices is a prime study object, proving on
one hand how international standardization can provide a direct benefit to
technological and societal development through the deployment of electrically
propelled vehicles, and highlighting on the other hand the dynamics of the international
standardization world where cultural and industrial differences should be resolved in a
climate of collaboration and consensus in order to avoid double work and the drafting
of conflicting (and thus useless) standards.
The paper will describe current work on the matter, concentrating on the characteristic
action points where standardization work is needed.

Publication year:2009

Keywords:standardization, battery