SIRET Clemence;Christoph Jehle (c.jehle@web.de);JeanPol Wiaux;Phil
Dolley;mailto:Claude.CHANSON@saftbatteries.com;Steph
anie Boulos;Bob Harrison
(robert.harrison@which.net);bob.harrison@intertek.com;
ecoups;
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CONFIDENTIAL SAFT
Feb 6 2012
C. Chanson
Batteries for UPS: main technologies
Advantages and disadvantages in UPS application
Batteries for UPS applications: type of batteries
 The main chemistries used in UPS applications are the
following
 Lead acid batteries (Pb acid)
 Nickel metal hydride batteries ( Ni-MH )
 Nickel cadmium batteries( Ni-Cd)
 Lithium ion batteries ( Li-ion and Polymer Li-ion)
 According the manufacturer and the battery usage,
different products are proposed:
 Technology specifics : Pb acid VRLA or flooded, Ni-Cd
pocket plates or sintered, Li-ion NCA cathode, NMC
cathode, free electrolyte or polymer, etc…
 Application specifics: power batteries for high rate
discharge ( less than 1 hour), energy batteries for low
rate discharge.
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C. Chanson
Batteries for UPS applications: markets shares
 Lead acid market share for UPS application is around 95%.
 Ni-Cd and Ni-MH cells have a few percent market share for
industrial UPS
• Volumes in 2011 in Europe represents around 500 MWh/y
(TBC)
 Li-ion are being proposed both for “consumer” and “industrial”
UPS. The market share is still small, but growing.
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C. Chanson
Batteries for UPS applications: performances
 For UPS application, some specific technical properties may be
considered as more relevant:
 Power and energy  according UPS specification
 Energy density  size and weight of the equipment
 Energy efficiency  battery recharge time and cost
 Maintenance charge energy saving
 Maintenance operations  service organization and cost
 Life duration  total life cycle cost, and replacement scheme
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Sept 26, 2012
C. Chanson
Power, Energy, Energy density
 For each chemistry, full range of energy and power
batteries are available to fit different UPS specifications.
 Volumetric energy
density at cell level:
range of characteristics
according the battery
type.
 The UPS energy density
depends in addition on
the system design. The
battery pack, rack,
shelves, or cabinets
layouts are not
considered in this
graph.
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Sept 26, 2012 C. Chanson
(Source: J.M. Tarascon, Amiens University, France, and
handbook of batteries McGraw hill ed.)
Energy efficiency -1
 The energy efficiency is the ratio of the discharged energy vs the
charged energy. It corresponds to the product of the voltage efficiency
by the coulomb efficiency. It of course depends on many factors, and
mainly on:
•
•
•
•
Battery chemistry and technology
Temperature
Currents for charge and discharge
Battery ageing
 A comparison can proposed based on new batteries designed for UPS or
similar application, at room temperature and low currents (1).
(1) Energy analysis of batteries in photovoltaic systems. Part I:Performance and energy requirements
Carl Johan Rydh , Bjôrn A. Sande, Energy Conversion and Management 46 (2005) 1957–1979
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Sept 26, 2012 C. Chanson
Energy efficiency -2
 Characteristics of technologies applicable to UPS usage:
 Lead acid coulomb efficiency considered at 82% (2) , approximate
voltage efficiency: (2V)/(2.26V) = 88%, leading to energy efficiency =
(87%)(90%) = 72% (3)
 Ni- Cd and Ni-MH have a similar behavior: coulomb eff. 85% and
voltage efficiency: (1,23V)/(1,38V) = 89%, energy eff. = 76% (4)
 Li-ion have a coulomb efficiency close to 100% ( no side reaction
when charged up to 100%), and voltage efficiency (3,6V)/(3,75V)
=96%, leading to an energy efficiency = 96% (5)
(2) A Study of Lead-Acid Battery Efficiency Near Top-of-Charge and the Impact on PV System Design
John W. Stevens and Garth P. Corey, S.N.L,USA (photovoltaics.sandia.gov/docs/.../batpapsteve.pdf )
(3) Lead acid battery lecture (ECEN 4517/5517)(ecee.colorado.edu/~ecen4517/materials/Battery.pdf)
(4) Saft Ni-Cd technical leaflets: SPH range, Uptimax range (www.saftbatteries.com)
(5) Saft Li-ion technical leaflet: Evolion system(www.saftbatteries.com)
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Sept 26, 2012 C. Chanson
Maintenance charge
 Why a maintenance charge:
•
•
•
In order to maintain the battery capacity at his maximum and compensate self
discharge, a maintenance charge is generally required by the battery supplier.
The maintenance charge correspond to the battery manufacturer specification,
and can be applied in several ways: continuous current or pulses, current or
voltage controlled, etc..
In general, this maintenance charge represents a fraction of the energy
consumption of the global battery system including electronics.
 Typical values of currents for Pb-acid, Ni-Cd and Ni-MH are in the range
of C/5000 to C/500 rate( ie 20 to 200 mA for a 100 Ah battery). So the
total consumption of energy per year will be 2 to 20 times the battery
energy (6) (7) (4)
 For Li-ion, due to the better charge efficiency, the total energy
consumption will be 0,1 to 0,5 time the battery energy, to compensate
self discharge (5)
(6) R.F. Nelson, »Valve-Regulated Lead-Acid Batteries », p 258, published by Patrick T. Moseley,Jurgen
Garche,C.D. Parker,D.A.J. Rand (http://books.google.fr/books?id=5R...)
(7) Enersys leaflet “powersafe” US-FL-IOM-002 January 2007 (www.enersysreservepower.com/.../USFL-IOM-0..)
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Sept 26, 2012 C. Chanson
Maintenance operations and life duration
 Maintenance operations may be requested, particularly in case of nonsealed batteries: according the battery manufacturer specification, filling
and other maintenance operation may be requested on the battery or the
system.
 Life duration of a battery may depend on the usage conditions,
temperature, charge systems, etc..
 The values announced by the manufacturers are in the following ranges
for ambient temperature up to 30°C:
- up to 10 years for lead acid
- up to 20 years for Ni-Cd, Ni-MH and Li-ion
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Sept 26, 2012 C. Chanson
Integration and recyclability
 Different type of systems can be proposed according the size of the
system:
 Small systems (typically lower than 10 kWh): in general, small
system are more integrated for more “standard type” operations:
few maintenance possibilities, standard interchangeability. In this
case, battery manufacturers consider application of the battery
directive: system design should integrates the possibility to remove
and recycle the battery or battery cells.
 Large systems: these are more oriented towards specific installation
and maintenance, with a lower cost replacement unit: this leads in
general to a lower integration of electronics and electrochemical
cells. In this case, there should be no specific difficulties dismantle
and handle batteries modules or battery cells for recycling.
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Sept 26, 2012 C. Chanson