3.2. Ventilation and cooling
During operation (charge or
discharge), STM batteries generate
heat, like all electrochemical
systems. In daily use, a steady heat
accumulation must be avoided.
As a result, the battery needs a
good cooling system in order to
disperse the dissipated heat
efficiently.
The free space of 10 mm to 20 mm
between rows of STM 5-100 MR
and STM 5-140 MR monoblocks
on their large sides serves as a
cooling corridor.
In addition, heat dissipation
can be improved by providing
ventilation space above and/or
underneath the STM 5-100 MR
and STM 5-140 MR monoblocks.
In the case of forced air cooling,
the ventilators will blow cold air
vertically and horizontally across
the batteries. All cooling systems
will be dimensioned to ensure the
most homogenous temperature of
the monoblocks in one battery.
Furthermore, it is recommended to
control the battery temperature by
sensors or thermostats, which can
be supplied by Saft on request.
The optimized solutions for a
cooling system must be designed
for every battery, depending on
the type of car, its use, the type
of battery etc.
&
Special case of STM 5-100 MRE
liquid cooled monoblocks
Cooling of these monoblocks is
effected by circulation of liquid in
fluid chambers on the large sides.
The basic design rules for a liquid
cooling system are as follows:
- the maximum number of fluid
chambers in a hydraulic series
is limited to 3 with a pressure
loss of < 80 mbar.
- in the best interest of thermal
balance, two fluid chambers that
belong to one monoblock will
be connected through two
independent cooling circuits.
- water flow of 40 l/h/series of
3 fluid chambers with a
maximum pressure of 0.3 bar in
the hydraulic circuits must be
homogenous. It must be assured
that no preferential waterflow
exists that would cause uneven
cooling of the monoblocks.
When replenishing the cooling
liquid, care should be taken that
no air bubbles form that would
cause partial or no cooling at all,
thus accelerating the aging
process or the destruction of the
monoblocks or the battery.
- the thermal exchange system of
the cooling liquid/air is not
included in the supplies from
Saft, except under special
contract. This includes:
distribution hoses, draining
accessories, pump, radiator.
- during the mounting of the
battery and specifically during
the installation of the electric
and hydraulic circuits (filling and
cooling), particular care must be
taken that none of these three
circuits is interconnected.
- for details about the material and
dimension of the hoses of the
cooling system see appendix 7.
3.3. Assembly of centralized
water filling system
3.3.1. Precautions and
recommendations
The centralized water filling
system links a number of
monoblocks in hydraulic series.
The installation of such a system
must therefore be effected with
a maximum caution to avoid any
risk of gas or electrolyte leakage
to ensure good operation
compliant with required safety
regulations.
Important:
•
To ensure that the hydraulic
system is sealed, (no gas and/or
water leakages), the connection
of the ramp with hoses must be
done carefully.
Whenever a
leakage occurs
(possible after
some period of operation), it
must be repaired immediately.
• To minimize the risk of current
leaking into the hydraulic
system (which is carrying gases
and water) verify the following:
- the hydraulic connection must
always follow the electrical one,
in order not to create a potential
difference higher than that
between two cells at opposing
ends of the hose connection.
- the number of monoblocks that are
connected in hydraulic series is
limited to 10 (50 cells maximum),
which in turn limits the nominal
voltage of one ramp to 60 V.
11
Summary of Contents for STM 5-100
Page 1: ...Technical manual installation operation and maintenance for Ni Cd STM MR MRE monoblocks type ...
Page 23: ...Appendix 1 20 Monoblock STM 5 100 MR G RD equipped Positive left Filling right ...
Page 24: ...21 Appendix 2 Monoblock STM 5 100 MRE G RD equipped Positive left Filling right ...
Page 25: ...Appendix 3 22 Monoblock STM 5 140 MR G RD equipped Positive left Filling right ...
Page 26: ...Appendix 4 23 Monoblock STM 5 140 MR D RG equipped Positive right Filling left ...