Page 15 - TeamStrunz_e_mobil_structure_study_en

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Hydrogen/in conjunction
with fuel cell
Li-Ion
Supercaps
NiMH
Lead acid
Advan-
tages
-
Energy density three times
as high as gasoline
(33.3 kWh/kg)
-
High specific energy
-
High cell voltage
-
Good cylindrical stability
and service life with (ther-
mal and battery manage-
ment) possible
-
No »memory effect«
-
Low self-discharge
-
Reliable and robust
-
Long service life,
very high cycle count
-
Very high power
density
-
Reliable and robust
capable of deep
discharge
-
Long service life in
discharged status
-
At low temperatures
capable of deep
discharge
-
Low manufacturing costs
(material price, technology)
-
Available in large quantities
various dimensions
Disad-
vanta-
ges
Low efficiency (48%),
however still better than
combustion engine
Storage of hydrogen is
problematic. Infrastructure
not yet available
High costs for fuel cell
system
Heat dissipation of low
temperature fuel cell is
problematic
High costs
Reactive with air and
moisture
Complex battery
management (electrical and
thermal)
High self-discharge
(parasitic, internal
currents)
Large voltage swings
Very low energy
density
High monitoring
effort
High danger potential
in the case of abuse
High self-discharge
(particularly at increa-
sed temperature)
Poor cyclic efficiency
Only capable of fast
charge
Relatively low energy
density
In general low cycle stability
Not capable of deep discharge
Low energy density
Poor charge retention
(Sulphatization)
Short service life
Possibi-
lities for
further
deve-
lopment
-
Use of new, more
cost-effective catalytic
converters
-
Further development of the
high temperature fuel cell
for the mobility sector
-
Use of new, storage possi-
bilities for hydrogen
-
Cost effective and readily
available procedures for
production of hydrogen
-
Short-term further develop-
ments on Li-Ion
-
Storage concerns the
electrode materials for
increasing the storage
density, Electrolyte, sepa-
rators, housing to improve
performance and safety
-
Battery management for
achieving long service-life
and cycle count at concur-
rent high discharge depth
-
EEStor Inc. (Austin/
Texas): Capacitor
with ferro electric
ceramic layer
(barium titanate) as
dielectric (Estimated
energy density up
to 340 Wh/kg, no
products yet)
-
Reduction of self-
discharge through
improved separator
materials
-
Through the use of the lead
anode through a carbon elec-
trode (Axion) an inexpensive
„battery supercap“ can be
implemented
-
Shorter charging times
-
Higher power density
-
Improved lifecycle duration
Sum-
mary
Good suitability for energy
storage/conversion in the
stationary sector
mobility area formerly limi-
ted to special applications
Cost reduction necessary
for automobile use
Cost effective and environ-
mentally friendly manufac-
turing of hydrogen must be
implemented
Highest potential, however
still high costs for use in
electrotraction:
Low quantity for low num-
ber of E-vehicles is initially
problematic
Optimized production and
series maturity for the
consumer products
The combination
of Supercaps with
saving of high
energy density offers
potential
Due to the relatively
low energy density the
high self-discharge
and the poor fast
charge capacity NiMH
rechargeable batteries
have only limited
suitability for PHEV
and BEV
However the system is
mature and extremely
robust
Lead-acid rechargeable batte-
ries are not suitable for PHEV
and BEV due to the low energy
density and short service life
Fig. 6: Comparison of different energy storage devices
6
6 Author’s own illustration