New battery technology

The 21st Worldwide Battery, Hybrid and Fuel Cell Electric Vehicle Symposium & Exhibition NEW BATTERY TECHNOLOGY
The various technologies tested in industry Nowadays, the battery is the electric vehicle’s element that progresses most, with regards to increasing its power and range. Researchers are trying to make it light,powerful and cheap, like the small cells in our mobile phones and portablecomputers.
Manufacturers are working on it throughout the world. Among them, Saft and Bolloréin France, and Zebra in Switzerland.
Although the principle remains the same to store electricity – two electrodesswapping their electrons – various electrochemical couples are being used, eachwith its own features.
Electric energy is measured in watt hours (wh). To give a rough idea, a privatevehicle uses around 150Wh from its battery to run 1km, compared with 1000whfor a 10t bus (100 wh/tonne). Presently, to provide a range of 200km to a light car,nearly one ton of lead battery would be needed! Much too heavy, the energy mustbe condensed;this is the challenge. One of the comparisons between batteries is their “energydensity”, i.e. the quantity of energy they produce for the same weight (wh/kg).
The most widespread:
The lead-sulphuric acid battery, Pb-acid. Energy density: 30 to 40 wh/kg
It came into existence around 1850. The electrodes can be arranged either in plates
or in parallel tubes depending on the performance sought. Lead is used in nearly
all small electric vehicles like fork-lift
trucks, golf cars and electric wheelchairs.
But this electrochemical couple is not
efficient enough for roadworthy vehicles:
it is heavy and of low energy density. The
cost – significantly lower than other
technologies – is the main attraction for
car manufacturers. 36 V batteries are being
tested by some manufacturers. Researchis currently being carried out on new, lighter internal architectures (pseudo-
bipolar and bipolar), and new ways of
processing the active substances (compression, metallic foams).
Advantages: Cost, mass production, well recycled by the industry.
The 21st Worldwide Battery, Hybrid and Fuel Cell Electric Vehicle Symposium & Exhibition New battery technology .(cont.)
Commercialised in France:
Nickel-cadmium, NiCd. Energy density: 40-60 wh/kg
This type of battery is produced by SAFT, among others. It is used in the following electric
cars marketed in France: the PEUGEOT Partner
Berlingo and Saxo. In the US, NiCd is usedby FORD in the Think City. Considered asbeing effective and reliable, NiCd batteriescan nonetheless, depending on the way theyare used, have a “memory effect” whichreduces their usable capacity. However, that effect is reversible. Because of its cost and a lower resistance to improper use, the sealed
technology is hardly used for traction
Advantages: Reliable, robust, good resistance to quick charge and to cold.
Nickel metal hydride, NiMH. Energy density:
70-80 wh/kg
NiMH batteries are all sealed. Because of their
high power and cycle features, these batteries
are mainly used in hybrid vehicles (HONDA Insight
and Civic, TOYOTA Prius 1 and 2). The
manufacturer, PANASONIC, developed
successively two generations of NiMH storage
batteries for TOYOTA. The second generation ofprismatic elements, fitted on the hybrid vehiclePrius 2, is a reference in efficiency and reliability.
The manufacturer gives an eight-year guaranteeon that component.
Advantages: Low-pollution technology, good performance as regards power, good
lifespan.
Zebra, NA/NiCl2: 100-120 wh/kg (operational)
This technology has been developed specifically for electric vehicle applications of
heavy and public transport. The internal working temperature is between 270°C and
350°C. The elements are enclosed in an insulated case whose external surface has a
temperature of around 30°C. The ceramic electrolyte is the determining element in
regard to performance and reliability. The battery is in a one-piece block, integrating
everything it needs. The first five buses in France fitted with Zebra batteries were
delivered in Lyons in November 2004.
Advantages: High energy density, good energy efficiency, available assembled.
The 21st Worldwide Battery, Hybrid and Fuel Cell Electric Vehicle Symposium & Exhibition New battery technology .(cont.)
New Tendencies:
Lithium-ion, Li-ion: Energy density: 120 to 150 wh/kg
To date, it is the most effective couple.
Unlike the couples described above,
electrolyte, which is an advantagebecause it eliminates the parasite waterdecomposition reaction. In France, thistechnology is developed by SAFT. Thistype of storage battery is still very little used, mainly because of its cost. It is dueto be fitted on the vehicles of SVEcompany (H ASSOCIÉS). The lithium technology is
already widespread for small cells (telephones, computers…). It is mass-produced
in South-East Asia, which leads to expect lower production costs. After a difficult
start, this technology is now progressing fast.
Advantages: Light and effective. Good French know-how despite the competition
from emerging countries.
Lithium metal polymer: 120-150 wh/kg.
A technology for the future, still in the prototype stage for electric vehicles.
Theoretically, this technology should be more effective than the existing lithium-
ion batteries. It works at 80°C and is thus unaffected by external conditions, but it
requires to be used regularly in order to avoid its cooling down. Because it is
made of thin electrodes placed one on top of the other around a solid extruded
polymer electrolyte, the production costs should be attractive. In France, this
technology is developed by BATSCAP company (BOLLORÉ TECHNOLOGIES and EDF).
In Canada, AVESTOR company, a subsidiary of Hydro-Quebec, was the first to
market high-capacity modules for stationary applications.
Advantages: High energy density, anticipated low cost.
The 21st Worldwide Battery, Hybrid and Fuel Cell Electric Vehicle Symposium & Exhibition New battery technology .(cont.)
Chart 1 Comparing the technical features of storage batteries
Li--polymer
* The lower and upper limits range corresponds to various element sizes (large elements usually have higher energy) or to various types of applications. (1) sealed; (2) tubular

Source: http://www.elektropower.hu/new_battery_technology.pdf