Special Report - VARTA PartnerNet UK

Uwe Köhler and
Jörg Kümpers,
NBT GmbH, Hannover
Eberhard Meissner,
VB Autobatterie
GmbH, Hannover
Fig. 1:
NiMH Power Assist
Battery for hybrid
electric vehicles
(energy content:
2.8 kWh, maximum
discharge power:
55 kW)
Special
Report
High-Performance Batteries for
New Automotive Applications
1. Introduction
2. Development Trends in the Automotive
Industry
3. Requirements on Battery Systems
1 Introduction
Triggered by a variety of new applications in vehicles
of the future, battery manufacturers are
currently investing much activity in developments
aimed at meeting the growing technical
demands of vehicle manufacturers. These new
applications range from traction batteries for hybrid
electric vehicles (HEV) to new battery systems
for the 42V vehicle electrical power supply
systems of tomorrow. Interest in hybrid electric
vehicles has grown considerably, as pure electric
vehicles (EV) have failed to live up to
expectations. In addition to the limited range of
electric vehicles, the high costs of the large traction
batteries needed for EVs are also responsible
for their poor acceptance on the market.
1
4. Battery Systems for the Vehicles of
Tomorrow
– Lead-Acid Batteries
– Nickel - Metal Hydride Batteries
– Lithium-Ion Batteries
5. Summary and Outlook
6. Varta – The Battery Experts
7. References
Hybrid electric vehicles represent an interesting
compromise between an environmentallyfriendly
electric vehicle and a vehicle driven by
a combustion engine without range restrictions.
By lowering the fuel consumption and reducing
exhaust gas emissions, HEVs can make a significant
contribution to increasing the environmental
compatibility of automobiles.
Besides hybrid electric vehicles, there are a
variety of technical developments underway
that are aimed at improving the comfort, safety,
environmental compatibility and cost-effectiveness
of conventional vehicles through the
use of innovative electrical components. These

High-Performance Batteries for
New Automotive Applications
new vehicles can be expected to exhibit a growing
need for electrical performance and power
(Fig. 2). In order to meet these needs, the electrical
architecture of the vehicles will have to
change. Under discussion are dual-voltage
electrical systems (14V/42V), high-voltage electrical
systems, implementation of Integrated
Starter/Alternator and energy recovery devices.
These are aimed at boosting the efficiency of
producing, distributing, controlling and storing
of electrical energy within the vehicle.
Performances required for future electrical systems
Maximum Average
Application performance (W) performance (W)
Electrical wind shield heating 1,500 120
Electro mechanical valve actuation (EMVA) 1,800 - 3,400 700
Electro hydraulical valve actuation (EHVA) 400 200
Electrical cooling fan 650 50
Electrical water pump 600 100
Electrical power steering (servo) (EPS) 900 200
Electro mechanical brake 3,000 50
Wave stabilisator 2,000 150
Electrical fuel pump 450 150
Electrical A/C compressor 4,000 1,000
2 Development Trends in the Automotive Industry
The architecture of future energy supply systems
for vehicles will be determined by a number
of different factors.
Lower fuel consumption: The more efficient
use of fuel in vehicles is becoming increasingly
important, given the rising costs of fossil fuels,
stricter legislation governing emissions and regulations
aimed at cutting fleet fuel consumption.
The potential fuel savings in hybrid electric
vehicles can be as much as 50% compared to
conventional vehicles. Yet even in conventional
vehicles, significant improvements can be made.
Efficient fuel consumption in this situation is a
matter of generating, storing and using electrical
energy efficiently within the vehicle. The potential
savings can range from around 10% to
way above 20%.
2
Fig. 2: Future vehicle electrical supply systems
Power (kW)
5
4
3
2
1
0
1995 2000 2005 2010
New functions: There will be many components
requiring significantly higher voltages
than the normal 14V on offer today. For powerhungry
consumers such as electrically-heated
windows, DC converters for transforming to
higher voltages do not represent a cost-efficient
solution in the long term. Modern combustion
engines (especially diesel engines) also need
greater starting power. The subsequent shortening
of the starting routine that this allows
cuts emissions and reduces noise. Fast and
clean starting is a key requirement for the introduction
of start/stop systems, which contribute
significantly to saving fuel in urban traffic.
The recovery of braking energy and acceleration
assistance will need even higher power,
making increased operating voltages absolutely
essential.
Average power
performance IntegratedStarter/Alternators
with lead-acid
batteries (42V)
Average power
performance
conventional
alternators (14V)
Average power
demand of vehicle
electrical power
supply systems

Comfort features: With the introduction of
further comfort features, the overall demand for
electrical energy on board the vehicle will also
increase. A belt-driven system can currently
provide a maximum of 2 to 2.5 kW of electrical
energy. Because the power generated by the
alternator however is significantly less when
the engine is idle, extreme driving conditions in
urban traffic with lots of waiting can lead to insufficient
energy being available to supply the
new comfort features. This deficit needs to be
bridged with batteries.
Safety: In modern vehicles, only a limited number
of components that are critical for the
vehicle´s operation use electrical energy, e.g.
brake lights, airbag, ABS, ESP. This will change
with the new “drive-by-wire” technologies,
which include functions as steering, braking,
locks, etc. These systems will require additional
electrical energy, and in many cases at
relatively high levels, at least for short periods.
Besides technical advantages the changeover
from mechanically to electrically-driven systems
and components also offers the automotive
industry opportunities to lower production
costs and make better use of the available
space.
The new challenges facing battery systems
make it all the more important to be able to determine
the actual State of Charge (SOC) and
the State of Function (SOF). This applies just as
3 Requirements on Battery Systems
42V Vehicle Electrical Power
Supply Systems
With the introduction of new functions such
as the start/stop system, the technical demands
placed on the battery system are set to change
dramatically. Start/stop systems require fast,
quiet and low-emission vehicle startup, and
with a far greater frequency than is common
today. In addition to providing the electrical
energy for the starter system during startup,
the battery also has to supply power to all
consumers at times when the engine is switched
off. Under certain circumstances, this can
mean that the battery has to deliver a continuous
power of 1 kW for more than a minute.
After discharge, the combustion engine needs
3
much for hybrid concepts as it does for the
other on-board battery systems of the future,
and will have far-reaching consequences for the
battery industry. The battery will cease to be a
passive component, and will become a central
system component requiring monitoring and
management functions in order to safeguard
the vehicle´s functionality and safety.
to be restarted. The previously discharged
battery needs to be recharged as quickly as possible
before the vehicle comes to another standstill
and the engine is switched off again. Over
the life of the vehicle, tens of thousands of such
charge/discharge cycles can be expected. This
will increase the battery´s capacity throughput
by at least one order of magnitude compared
to the present situation.
The demands on battery discharge power
grow further if both the combustion engine
needs to be started and electrical acceleration
assistance (boosting) is used (approx. 10 kW
for a few seconds). In regenerative braking
(energy recovery), the recharge capability of the
battery needs to be of the same magnitude.
Fig. 3: The Battery
Management System
(BMS) will be part of
an intelligent electrical
supply system.
The BMS delivers
information about
State of Charge and
State of Function.

High-Performance Batteries for
New Automotive Applications
Fig. 5:
Varta 36V/42V VRLA-
AGM – battery for
application in advanced
vehicle
systems with high
power demand
Integrated starter/alternator systems of various
designs are under development for start/stop
systems, boosting and energy recovery systems.
The differences between these systems
are related to the type of electric motor used,
the transmission ratio to the crank shaft and the
arrangement of the clutch systems.
High-Voltage Systems for Hybrid
Electric Vehicles (HEVs)
The biggest motivation behind the development
of hybrid electric vehicles is the dramatic reduction
in fuel consumption and exhaust gas emissions.
HEVs, with their typical power assist and
energy recovery functions, generally work at
operating voltages in excess of 200V. The battery
capacity depends on the minimum requirements
for energy storage and electrical performance.
Virtually all hybrid electric vehicles use
relatively small batteries that have been designed
specifically for high discharge and
recharge performance. Pure electrical propulsion
has been abandoned in favor of high
power capabilities. The reduction in fuel consumption
is achieved by the optimized combination
of combustion engine and electrical propulsion
system, and by the recovery of braking
energy.
4 Battery Systems for the Vehicles of Tomorrow
Lead-acid batteries (Fig. 5), nickel - metal hydride
(NiMH) batteries and lithium-ion (Li-Ion)
batteries are all under discussion for use in the
vehicle electrical systems of the future. Nickelcadmium
(NiCd) batteries have very poor prospects
because of the same environmental con-
4
CIDI internal
combustion engine
5-speed manual transmission
& automated clutch Final drive
Integrated power electronics
Typical power requirements for HEV battery
systems vary from 20 kW to 60 kW. Because
of the enormous energy throughput, high demands
are placed on the long-term stability of
the battery system. These battery systems
need to provide sufficient power for the vehicle
to travel at least 200,000 km.
cerns that caused them to be ousted by NiMH
batteries in many portable battery applications.
High-temperature batteries such as sodiumsulfur
and sodium-nickel-chloride exhibit high
energy losses due to their very high internal
operating temperature, which can be tolerated
only in pure electric vehicles.
Supercapacitors capable of delivering extremely
high power are under development for applications
with extreme demands in terms of performance
and endurance. However, they exhibit
only low specific and volumetric energy densities,
and costs and weight of the power electronics
needed to manage the steep voltage
characteristics have so far seriously limited their
application.
Electrochemical storage systems, on the other
hand, deliver more energy at a more stable voltage
level. They can be designed either to deliver
a high power output or have a high energy
Battery
pack
Final drive
5-speed manual
transmission &
automated clutch
Electric machine
Fig. 4:
Energy recovered
during braking
can be reused for
acceleration
Picture:
DaimlerChrysler AG

Fig. 6: Specific data of different energy storage systems
Specific cold cranking
power (W/kg) 1)
80
60
40
20
300
200
100
Specific energy (Wh/kg) 2)
PAG
POB
AGM
Present demands are met by a standard
SLI battery of about 20 - 25 kg
• Cold cranking power: ~4 kW
• Energy content: ~1 kWh
• Energy throughput: ~100 kWh
PAG: Lead-calcium-silver technology
POB: Power-optimized battery
AGM: Absorptive glass mat
Li-Ion: Lithium-Ion
NiMH: Nickel - metal hydride
Li-Ion
storage capacity. Depending on the specific application,
the requirements on the energy and
the power density need to be harmonized, at
least in part.
Lead-Acid Batteries
Through technical modifications, e.g. reduced
electrode height, improved grid design and different
arrangement of the terminals, the performance
behavior of lead-acid batteries can be
significantly improved. This was realized, for example,
in the power-optimized battery (POB)
from VB Autobatterie. In this battery, only minimal
compromises are made in terms of specific
and volume-related energy values. The immobilization
of the electrolyte in an absorptive
glass mat (AGM) brings about major improvements
in the cycle life. While there is some reduction
in the specific energy, the volumetric
energy density remains virtually unchanged.
5
NiMH
10 200 500
Specific
energy
throughput
of battery
(kWh/kg) 3)
1) t = 3 sec., Umin > 22V, T = -18 °C
2) t = 20 h, T = 20 °C
3) within 3 - 4 years
Considerably higher power capability can be
achieved through the use of ultra-thin electrodes.
Because thin electrodes cannot be processed
individually, electrode pairs, separated
from each other by an absorptive glass mat, are
spiral-wound to form a coil. The improved performance,
however, is achieved at the expense
of the specific energy, the energy density and,
depending on the design, the endurance.
Figure 6 shows the three key parameters
specific energy (Wh/kg), specific cold cranking
power (W/kg) and specific energy throughput
(kWh/kg) of various lead systems, compared to
the alternative NiMH and Li-Ion systems. The
crucial advantage of the Lithium-Ion system is
its higher specific energy. The most prominent
feature of the NiMH system is its drastically
higher energy throughput.

High-Performance Batteries for
New Automotive Applications
Fig. 8:
Battery system
for use in a hybrid
electric bus (energy
content: 14 kWh,
power: 80 kW)
Nickel - Metal Hydride Batteries
(NiMH)
Of all the new battery systems, nickel - metal
hydride is regarded worldwide as the most technically
advanced. Therefore a large proportion of
new-generation electric vehicles introduced
into the market have already been equipped
with batteries of this type (e.g. Toyota RAV4, General
Motors EV1). But the market volume of
this battery types is still very small. In addition
to the actual NiMH high-energy cells which have
been developed to high specific energy levels
of approx. 80 Wh/kg, two product lines are of
interest for hybrid electric vehicles and the vehicle
electrical power supply systems of the future.
These product lines have been developed
specially for high power requirements (Fig. 7).
Power (P) Cells
A typical application scenario for NiMH power
cells would be the propulsion battery for conventional
hybrid electric vehicles, with a specific
range when used in purely electrical mode
(e.g. hybrid electric buses). High performance,
rapid-charging capabilities and a long service
life are all important for such applications. Due
to the relatively high capacity values (> 40 Ah)
resulting from the energy requirements, the
cells are produced in prismatic form. Even at
large capacities, this construction enables a relatively
large cell surface, which is required for
dissipating the waste heat generated during
battery operation.
6
Fig. 7:
NiMH-Product lines for high power requirements
Power(P)-Cells High-Power(HP)-Cells
60, 40 Ah 5, 8, 12 Ah
prismatic cylindric
< 60 Wh/kg < 45 Wh/kg
< 300 W/kg < 1300 W/kg (90% SOC)
The high requirements in terms of electrical
power are met at the expense of the specific
energy and energy density, which up to 60
Wh/kg and 150 Wh/l lie far below the level of
high-energy cells. However, the performance
during discharging and charging is significantly
better. Even when discharging with a 10minute
current (6 C rate), 85% of the stored
energy can be converted to useful energy. The
maximum specific power lies in the region of

Fig. 9:
NiMH-40V-battery for
new vehicle electrical
power supply
around 300 W/kg. Generally speaking, highpower
cells can be completely recharged within
around 60 minutes. Partial charging up to
around 80% is even possible within 10 minutes.
Rapid charging is limited by the temperature
rise within the cells, caused by the exothermic
formation of hydrides, and losses generated by
electrical resistance, as well as gas evolution at
the positive electrode in high states of charge.
High-Power (HP) Cells
High-power cells are the most important development
of the NiMH system. They have
been designed mainly for “Power-Assist” applications
in state-of-the-art hybrid electric vehicles,
where the improvement of energy efficiency
and the reduction of exhaust gas emissions
are at the forefront of the development
work. Their use in new 42V vehicle electrical
power supply systems is also very promising.
The NiMH system has been optimized specifically
for these applications to provide significantly
greater performance. HP cells are currently
available with capacities ranging from
5 Ah to 12 Ah. Because of their relatively low
capacities, these cells are produced in cylindrical
form. Positive and negative electrodes, separated
by a polymer fiber sheet, are spirally
wound. This process is inexpensive, and is currently
used to manufacture billions of portable
batteries.
HP cells can be continuously discharged at discharge
rates of up to approx. 40 C (1.5-minute
discharge) (Fig. 10). The full capacity is available
at a high voltage in excess of 0.9 V (approx.
80% of the open circuit voltage). The maximum
specific power output of HP cells can be up to
1,300 W/kg (Fig. 11). These cells can also be
charged from completely discharged state at
very high currents. At a charge rate of approx.
20 C, HP cells can be charged to approx. 80%
7
Fig. 10: NiMH-HP 5 Ah
Discharge characteristics
Voltage (V)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0 1 2 3 4 5 6
Capacity (Ah)
Fig. 11: Energy power diagramm for different
NiMH cell design
Specific energy (Wh/kg)
75
50
25
5.5 A
27.5 A
55 A
82.5 A
110 A
165 A
220 A
0
0 250 500 750 1,000 1,250 1,500
Specific power (W/kg)
Power
High power

High-Performance Batteries for
New Automotive Applications
Fig. 12: Influence of DOD (depth of discharge)
on cycling endurance of NiMH cells
Capacity throughput
(Nominal capacity)
14,000
12,000
10,000
1)
2)
8,000
6,000
4,000
2,000
0
2,400
cycles
100%
1C/1C
5,000
cycles
80%
10C/10C
Depth of Discharge (DOD)
Charge/discharge rate
approx. 80,000
cycles
12%
18C/27C
> 300,000
cycles
5% 1)
2)
5C+2C/27C
SOC in less than 3 minutes. This corresponds
to a specific power absorption of approx. 1,200
W/kg.
A “Power-Assist” battery comprising 200 HP
round cells of 12 Ah nominal capacity is displayed
in Fig. 1. With a relatively low energy
content of 2.8 kWh, the maximum discharge
power at normal ambient temperatures is more
than 55 kW.
Fig. 9 shows the prototype of a NiMH battery
as may be used for a future 42V vehicle electrical
power supply system. The battery comprises
32 series-arranged individual cells, each
delivering a capacity of 12 Ah. With a system
weight of approx. 14 kg and an energy content
of approx. 500 Wh, the maximum electrical discharge
power at 20 °C is approx. 11 kW.
The service life – calculated in terms of either
calendar life or cycle life – is crucial for the costeffectiveness
of a battery system, particularly in
vehicle applications. The achievable capacity
throughput is mainly determined by the charging
and discharging conditions. Fig. 12 displays
the dominant influence of the depth of discharge
(DOD) on the attainable capacity throughputs
for NiMH systems tested under various
8
cycling conditions. Under a cycling regime with
one hour charging and one hour discharging at
100% DOD, the typical service life is 2,400 cycles
(reduction in capacity to 80% of the starting
value). If however the cells are run in a limited
SOC-window of 10% to 90%, the capacity
throughputs double. Operating the batteries
in a considerably smaller SOC-window (5%)
enables an extreme cycle life to be achieved
which corresponds to more than 14,000 times
the nominal capacity throughput. Internal resistance
and performance data remain virtually unchanged
in this cycling operation. This means
a consistent level of energy efficiency over the
battery´s entire lifetime.
Lithium-Ion Batteries (Li-Ion)
The tremendous weight advantage over other
battery systems makes the Li-Ion system a highly
attractive candidate for future energy storage
systems in vehicles with a particularly high demand
for electric energy. While NiMH highenergy
cells deliver specific energies of up to
80 Wh/kg, Li-Ion high-energy cells can deliver
approx. 130 Wh/kg, some 50% higher. The volumetric
energy density, at 270 Wh/l, lies approximately
20% above the density of equivalent
NiMH high-energy cells.
Current Li-Ion portable battery systems make
almost exclusive use of cobalt oxide for the
cathode material. However, this material cannot
be used in vehicle batteries due to its poor
availability and high costs. Battery manufacturers
are endeavoring to use cheaper materials
instead. In this regard, Varta has concentrated
on the lithium-manganese spinel.
Despite the tremendous technological advances,
the wide-scale use of Li-Ion batteries in
electric vehicles cannot yet be foreseen. This is
due firstly to the old problem of inadequate
energy density, as is also the case with other
battery systems. The other reason is that, even
when inexpensive materials are used, the price
for a battery with an energy storage capacity of
approx. 30 kWh is still prohibitively high. On the
other hand, smaller and higher-powered battery
systems are of great interest for 42V vehicle
electrical power supply systems and hybrid
electric vehicle applications. Similar to the NiMH
cell situation, there are two product lines that
are considered to offer the best opportunities
for the markets of the future (Fig. 13).

Fig. 13: Li-Ion-High-
Energy Cells with
40 or 60 Ah (prismatic)
and Li-Ion High
Power Cell with 6 Ah
High-Energy (HE) Cells
The main stimulus for the development of Li-Ion
high-energy cells is a dramatic improvement in
the storage of energy (in terms of weight and
volume) for supplying the vehicle electrical
power supply system. Vehicles equipped with
comfort features such as continuous air conditioning,
infotainment, will require electrical
energy storing devices of up to approx.
2 kWh. Because of their high specific energy,
Li-Ion batteries offer clear weight advantages
over today´s lead and NiMH high-energy batteries.
Were it to deliver the required storage
capacity of e.g. 2 kWh or so, the weight of a
lead battery would have to be around 50 kg,
while a high-energy NiMH battery would be approx.
30 kg. An equivalent Li-Ion battery would
weigh around 20 kg, not much more than a
modern lead starter battery. Fig. 16 shows a
Li-Ion high-energy battery (2.4 kWh) (operating
voltage: 40V) comprising 10 prismatic 60 Ah
cells.
High-Power (HP) Cells
While the high-power NiMH system has already
moved through the prototype stage and is
moving towards series production, a similar
development in terms of technology for Li-Ion
systems is still some way in the future. Nevertheless,
the results achieved to date have demonstrated
the enormous potential of this system
for the high-power sector.
9
Similar to the developments with NiMH, efforts
are being concentrated on relatively small cell
capacities in the range of 5 Ah to a maximum
of 10 Ah. The increase in power capability is
caused mainly by the use of thinner electrodes
and materials that are more able to carry high
currents. One fundamental problem is the conductivity
of the organic electrolyte, which is
around two orders of magnitude below that
of aqueous media. Similar to the high-performance
NiMH cells, the Li-Ion cells are manufactured
using a winding technology, for technical
and cost reasons.
Fig. 14 shows the voltage behavior of a Li-Ion
cell with a capacity of 6 Ah when it is discharged
with currents ranging from 6 A to
100 A. Even with a discharge current of 100 A
(approx. 16 C rate), voltages amounting to more
than 70% of the nominal voltage are observed.
The differences between the energy storage
and power behavior compared to an Li-Ion highenergy
battery can be seen in Fig. 15. While the
specific energy of an Li-Ion high-power cell of
55 Wh/kg is around half that of a high-energy
cell, its specific power is almost four times
higher at approx. 900 W/kg.
(cylindric) Fig. 14: Discharge characteristics of a
6 Ah Li-Ion High Power cell
Voltage (V)
4.2
4.0
3.8
3.6
3.4
3.2
3.0
2.8
2.6
2.4
0 1 2 3 4 5 6 7
Capacity (Ah)
2A
20A
35A
70A
100A

High-Performance Batteries for
New Automotive Applications
Fig. 15: Energy/power diagram (Ragone Plot)
for different Li-Ion cells
Specific Energy (Wh/kg)
125
100
75
50
25
0
0 250 500 750 1,000
Specific power (W/kg)
High energy cell
High power cell
Fig. 18:
Electrode belt manufacturing
for NiMH cells
The limited service life of Li-Ion batteries is still
their major weakness. It is currently determined
primarily by the drop in capacity over the
battery´s life. Depending on the size and type of
5 Summary and Outlook
The strengths of the existing lead-acid system
include high availability, low costs, an existing
recycling infrastructure and low self-discharge.
The system´s tolerance to limited overcharging
and deep discharging means only limited battery
management is required for existing applications.
The higher demands of future electri-
10
the cell, services lives of 2 to 4 years are standard
under normal ambient temperatures. This
is entirely adequate for most portable battery
applications, although in vehicle applications a
minimum service life of 5 years is required. The
advances that have been made in the stability
of the materials used have given rise to optimism
that this problem will be solved in the
foreseeable future.
cal power supply systems in vehicles, however,
make some battery management essential –
even for lead-acid batteries.
The results achieved with nickel - metal hydride
technology not only support their use in the hybrid
electric vehicles of tomorrow, but also open
up additional areas of application for new 42V
vehicle electrical power supply systems. With
specific power of approx. 1,000 W/kg, these
systems are in direct competition with capacitor
systems. At comparable performance values,
they offer an approximately 20 times higher
energy storage capacity. Particular strengths include
a high specific power and a high power
density, high capacity and energy throughput
and a long service life.
As far as applications in the vehicle sector are
concerned, lithium-ion technology still has some
way to go before it catches up with nickel -
metal hydride technology. The results achieved
so far, however, show that there is considerable
scope for technical enhancements. Specific
powers of up to 1500 W/kg at a specific energy
level of up to 80 Wh/kg would seem to be possible.
The main problem currently is the calendar
service life, especially under temperature
conditions that can be expected in automotive
applications.
Fig. 17: Li-Ion
High-Energy Module
(40V/60Ah)

Fig. 19:
Production of VRLA-
AGM batteries
6 Varta – The Battery Experts
VB Autobatterie GmbH is a joint-venture company
shared between VARTA AG and Robert-
Bosch GmbH, and has production sites in Germany,
Spain, France, Austria and the Czech
Republic, making it one of the largest manufacturers
of automotive batteries in Europe. Alongside
the ongoing further development of the
existing 12V (14V) lead-acid battery, VB is also
working on the development of the lead-acid
battery systems of tomorrow. This work mainly
involves AGM technology (AGM = Absorptive
Glass Mat) both for 12V (14V) and 36V (42V)
systems.
Batteries for new electrical power systems represent
a particular area of development focus.
These include various applications, such as the
upcoming 42V vehicle electrical system, multivoltage
vehicle electrical systems (14V/42V),
and separate systems for energy and power
storage. The spurs for these activities are the
rapidly-growing technical demands on electrical
performance in vehicles.
Varta Automotive’s NBT Technology Center focuses
on the development of new battery technologies.
These mainly include the nickel - metal
hydride and lithium-ion systems, which over
the last decade have become well established
in the portable battery industry and have superseded
other technologies (nickel-cadmium,
lead-acid) to a large extent in that field. Possible
areas of application for these technologies in
vehicles include 42V batteries for particularly
powerful vehicle electrical systems and supply
batteries for state-of-the-art, energy-saving and
11
ecofriendly hybrid vehicles. The features of
these new applications are high electrical performance
and the ability to deliver very highenergy
throughput over the vehicle’s service life.
The growing requirements of vehicle manufacturers
on battery system technology are being
met head-on through development activities focusing
on intelligent batteries. The aim is to develop
energy storage systems that use modern
electronics, for example, to determine their current
status in relation to readiness for operation,
state of charge, state of health, their remaining
service life and so on, to process this information
and to then forward it to the vehicle’s
electronic systems. VB Autobatterie and NBT
are both working closely with leading vehicle
manufacturers in these areas of research and
development.
Fig: 18:
Development of
Li-Ion cells
Fig. 20:
Electrode manufacturing
for NiMH cells

High-Performance Batteries for
New Automotive Applications
7 References
1. J. Kassakian Challenges of the New 42
Volt Architecture and Progress on its International
Acceptance; VDI Berichte No.
1415, p.21, VDI Verlag, Düsseldorf 1998
2. MIT Industry Consortium on Advanced
Automotive Electrical / Electronic Components
and Systems; c/o Massachusetts
Inst. of Technology, Laboratory for Electromagnetic
and Electronic Systems, 77
Massachusetts Ave., Cambridge, MA
02139
3. W. Buschhaus, A. K. Jaura, M. A.Tamor,
VDI Reports No. 1459, 1999
4. J. R. Pierson, J. P. Zagrodnik, R. T. Johnson,
Power Sources 67 (1997) 7
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Am Leineufer 51
D-30419 Hannover
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