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Strategies for the futher Improvement of Performance and Life of Lead-Acid Batteries for electric vehicle Applications

Objective



Objectives and content
This Project is designed to follow, and build upon, the
results achieved in Project BE 7297. While still
incomplete, certain key outcomes of the research can be
stated;
At the high rates of discharge experienced in EV
applications, active material utilisation is limited by
acid availability rather than paste conductivity. Thus
there is limited scope for improvements to specific by
additives to the positive active mass.
Key factors in the improvement of cycle life of the
valve-regulated (maintenance-free) lead-acid battery have
been shown to be, compression of the active mass by the
separator, the construction of the absorptive glass mat
separator and the nature of the charge regime employed to
recharge the battery after use.
It has been possible to enhance considerably, the
properties of the grid alloys used (strength and
corrosion resistance) by additions of tin and silver.
Work elsewhere has shown that rapid charging techniques,
as well radically reducing recharging times, can improve
cycle life of flat plate batteries apparently by
modifying active material structure. Such techniques can
however result in elevated temperatures in the battery,
which can be detrimental to negative plate life. Also
certain test regimes for EV batteries have demonstrated
that the negative plate can fail under the influence of
repeated and prolonged high-rate discharge pulses.
Accordingly the work in the Project will focus in three
areas;
The improvement of specific energy and life of leadacid batteries by the development of light-weight tubular
designs using the high-strength, corrosion resistant
alloys mentioned above. In this type of battery, the
positive active material is constrained between the alloy
spine and a porous fabric gauntlet, thus reducing
opportunities for paste shedding on softening during
cycling. Operating this type of battery under
compression, in an AGM design, will help to maintain
electronic conductivity within the active material,
especially with the lower paste densities required for
higher utilisation. Rapid charging techniques will also
be tried on these designs.
The study of separator compression across the plate
stack as a whole to determine the reasons for the early
initial loss of capacity experienced in these designs.
Several different separator designs will be studied to
overcome problems of acid stratification and relaxation
of compression during service.
The mechanism of the degradation of the negative plate
will be studied under conditions of electric vehicle
service and, following this, work will be carried out to
develop improved expander additives for the maintenance
of the required open structure in the negative active
mass.
The work is expected to result in further improvements to
cycle life and specific energy of the lead-acid battery
and a consequent reduction in running costs. This will
in turn make the performance and cost of an electric
vehicle more attractive and hence improve their
marketability. This will be done with out detriment to
the current inherent good recyclability of the lead-acid
battery.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

European Advanced Lead-Acid Battery Consortium
Address
42,Weymouth Street
W1N 3LQ London
United Kingdom

Participants (12)

AMER-SIL sa
Luxembourg
Address

8287 Kehlen
Accumulatorenfabrik Sonnenschein GmbH
Germany
Address
Thiergarten
63654 Büdingen
CENTRAL LABORATORY OF ELECTROCHEMICAL POWER SOURCES - BULGARIAN ACADEMY OF SCIENCES
Bulgaria
Address
2,Georgi Bonchev Street 2, Block 10
1113 Sofia
CMP Batteries Ltd
United Kingdom
Address
Salford Road
BL5 1DD Bolton
DARAMIC INC.
Germany
Address
31,Erlengang 31
22844 Norderstedt
DIGATRON INDUSTRIE-ELEKTRONIK GMBH
Germany
Address
12,Tempelhoferstrasse 12-14
52068 Aachen
Hollingsworth & Vose Co Ltd
United Kingdom
Address
Postlip Mills
GL54 5BB Winchcombe - Cheltenham
Oldham France SA
France
Address
Rue Alexandre Fleming
62033 Arras
POLITECNICO DI TORINO
Italy
Address
Corso Duca Degli Abruzzi 24
10129 Torino (Turin)
SEA TUDOR - SOCIEDAD ESPANOLA DEL ACUMULADOR S.A.
Spain
Address
2,Carretera Nacional Ii, Km 42
19200 Azuqueca De Henares
Universität Gesamthochschule Kassel
Germany
Address
40,Heinrich-plett-strasse
34132 Kassel
Zentrum für Sonnenenergie- und Wasserstoff-Forschung,Baden-Württemberg
Germany
Address
8,Helmholtzstrasse
89081 Ulm