U.S. patent application number 12/523009 was filed with the patent office on 2010-05-06 for fuel cell module for vehicles.
Invention is credited to Akira Aoto.
Application Number | 20100112412 12/523009 |
Document ID | / |
Family ID | 39241017 |
Filed Date | 2010-05-06 |
United States Patent
Application |
20100112412 |
Kind Code |
A1 |
Aoto; Akira |
May 6, 2010 |
FUEL CELL MODULE FOR VEHICLES
Abstract
A fuel cell module for a vehicle, which accommodates a
stacked-cell body which is provided with electric output terminals
for taking electric power from stacked power generating cells in a
metallic casing which has an insulation layer on its inner surface,
is disposed in a vehicle front room such that the stacked direction
of the power generating cells is a longitudinal direction of the
vehicle and the electric output terminals face the front of the
vehicle. An insulating cover made of insulating rubber which is
thicker than an insulation layer of a cover is disposed on the
exterior surface of the electric output terminals to prevent short
circuiting of the electric output terminals.
Inventors: |
Aoto; Akira; (Okazaki-shi,
JP) |
Correspondence
Address: |
KENYON & KENYON LLP
1500 K STREET N.W., SUITE 700
WASHINGTON
DC
20005
US
|
Family ID: |
39241017 |
Appl. No.: |
12/523009 |
Filed: |
January 11, 2008 |
PCT Filed: |
January 11, 2008 |
PCT NO: |
PCT/JP2008/050654 |
371 Date: |
July 13, 2009 |
Current U.S.
Class: |
429/515 |
Current CPC
Class: |
B60L 50/71 20190201;
H01M 8/2475 20130101; B60K 2001/0433 20130101; B60K 2001/0411
20130101; Y02T 90/40 20130101; Y02E 60/50 20130101; H01M 2250/20
20130101; B60K 1/04 20130101 |
Class at
Publication: |
429/34 |
International
Class: |
H01M 2/00 20060101
H01M002/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 16, 2007 |
JP |
2007-006859 |
Claims
1. A fuel cell module for a vehicle including a stacked-cell body
which is provided with electric output terminals for taking
electric power from stacked power generating cells, and a metallic
casing which has an insulation layer on its inner surface and
accommodates the stacked-cell body, wherein: an insulator which is
made of insulating rubber or an insulating resin and thicker than
the insulation layer is disposed between the insulation layer and
the electric output terminals.
2. The fuel cell module for a vehicle according to claim 1, wherein
the stacked-cell body is disposed in the vehicle front room, the
power generating cells are stacked in the longitudinal direction of
the vehicle, and the electric output terminals are oriented facing
towards the front of the vehicle.
3. (canceled)
4. The fuel cell module for a vehicle according to claim 2, wherein
the insulator is an insulating cover which covers the electric
output terminals.
5. The fuel cell module for a vehicle according to claim 2, wherein
the insulator is an insulating plate which is disposed on the inner
surface of the casing.
6. The fuel cell module for a vehicle according to claim 5, wherein
the insulating plate is fixed to a tightening member for the
stacked-cell body.
7. A fuel cell module for a vehicle, including: a stacked-cell body
which is provided with a positive electric output terminal having a
voltage higher than a ground electric potential and a negative
electric output terminal having a voltage lower than the ground
potential, and a metallic casing which has an insulation layer on
its inner surface, accommodates the stacked-cell body and has the
same potential as the ground potential, wherein: an insulator which
is made of insulating rubber or an insulating resin and thicker
than the insulation layer is disposed between the insulation layer
and the individual electric output terminals.
8. The fuel cell module for a vehicle according to claim 7, wherein
the stacked-cell body is disposed in the vehicle front room, the
power generating cells are stacked in the longitudinal direction of
the vehicle, and the electric output terminals are oriented facing
towards the front of the vehicle front.
9. (canceled)
10. The fuel cell module for a vehicle according to claim 8,
wherein the insulator is an insulating cover for covering the
electric output terminals.
11. The fuel cell module for a vehicle according to claim 8,
wherein the insulator is an insulating plate which is disposed on
the inner surface of the casing.
12. The fuel cell module for a vehicle according to claim 11,
wherein the insulating plate is fixed to a tightening member for
the stacked-cell body.
13. A fuel cell module for a vehicle, including: a stacked-cell
body having power generating cells stacked, and a metallic casing
for housing the stacked-cell body, wherein: an insulator made of
insulating rubber or an insulating resin is disposed between the
metallic casing and the surface of the stacked-cell body opposite
that of the vehicle body.
14. The fuel cell module for a vehicle according to claim 13,
wherein an insulator is disposed between the metallic casing and
individual surfaces, which are opposed to individual side faces of
the vehicle, of the individual stacked-cell bodies which
accommodate a plurality of the stacked power generating cell bodies
and are disposed on both side faces of the vehicle.
15. The fuel cell module for a vehicle according to claim 14,
wherein a thin insulating sheet thinner than the insulator is
disposed between plurality of the stacked power generating cell
bodies.
16. The fuel cell module for a vehicle according to claim 13,
wherein the metallic casing has an insulation layer on its inner
surface, and the insulator is thicker than the insulation
layer.
17. The fuel cell module for a vehicle according to claim 14,
wherein the metallic casing has an insulation layer on its inner
surface, and the insulator is thicker than the insulation
layer.
18. The fuel cell module for a vehicle according to claim 15,
wherein the metallic casing has an insulation layer on its inner
surface, the insulator is thicker than the insulation layer, and
the insulating sheet is thicker than the insulation layer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a structure of a fuel dell
module for vehicles.
BACKGROUND ART
[0002] In recent years, automobiles using fuel cells as a source of
drive energy have attracted attention as one possible measure for
addressing environmental problems. In conjunction with this, there
has been a noticeable effort to develop technology for installing
fuel cells in the front section of automobiles. For example,
Japanese Patent No. 3767423 describes a fuel cell-powered
automobile in which a fuel cell is installed in the front end of
the vehicle, the power generating cells of the fuel cell are
stacked in the width direction of the vehicle, and a circuit
breaker and an electric output terminal for receiving electric
power from the fuel cell are arranged on a side face of the
vehicle. In the described configuration, the fuel cell is housed in
a casing for protection.
[0003] Because the position of the electric output terminal for
receiving electric power from the fuel cell moves due to heat
expansion of the fuel cell, there has also been proposed a fuel
cell output terminal housed in a bellows as described in Japanese
Patent Publication JP-A 5-74473, and an output cable for receiving
electric power from the fuel cell covered with an insulator as
described in Japanese Patent Publication JP-A 2002-208314
[0004] Meanwhile, technology for producing high voltage fuel cells
having a large capacity has progressed, and high-performance
vehicles in which such cells are installed are now being studied.
However, as the voltage and capacity of fuel cells increase, there
dimensions such as width and length become large, possibly to the
extent that it may not be possible to stack the power generating
cells in the width direction, in which case the fuel cell cannot be
installed in the width direction of the vehicle. In such a case, it
might become necessary to stack the power generating cells in the
longitudinal direction of the vehicle and to install the fuel cell
in the longitudinal direction of the vehicle.
[0005] In a case where the fuel cell is installed in the
longitudinal direction within the front section of the vehicle, a
fuel pipe and the like connecting to the fuel cell are arranged on
the rear side in a fuel cell installing space of the vehicle in
view of safety. In such a configuration, the electric output
terminal from the power generating cells would likely be arranged
on the front end of the power generating cells, in the vehicle
front section, the side opposite to the connection ports of the
fuel pipe and the like.
[0006] When the electric output terminal is arranged towards the
front of the vehicle, the casing in which the fuel cell is housed
may be deformed if the vehicle body adjacent to the fuel cell is
deformed as a result of the vehicle colliding with an object.
Although an insulation coating is applied to the inner surface of
the casing for the fuel cell, the insulation coating can become
broken because of the contact between the deformed casing and the
electric output terminal, in which case the electric output
terminal and the casing may become electrically connected, possibly
resulting in a short circuiting of the electrical system.
[0007] When the fuel cell is installed on the vehicle front side as
described above, the power generating cells are stacked along the
longitudinal direction of the vehicle, and a side face of the
stacked-cell body becomes a side face of the vehicle. With such a
configuration, the side face of the casing in which the fuel cell
is housed might become deformed due to the deformation of the
vehicle side face in the event of a collision impacting the side of
the vehicle. When the side face of the casing is deformed, the
deformed casing comes into contact with the side face of the
stacked-cell body, resulting in a possibility that a short circuit
occurs between the individual stacked power generating cells
through the metallic casing. Even when the inner surface of the
metallic casing is insulation-coated, contact of the metallic
casing with the power generating cells may still damage the
insulation coating, with the result, again, that a short circuit as
described above may occur.
[0008] If a short circuit occurs between the electric output
terminal of the fuel cell and the vehicle or between the power
generating cells, there were problems that an abnormal electric
potential is generated in the power generating cells, for example,
sintering of a catalyst, oxidation of supported carbon, or the like
is generated, resulting in deterioration of the catalyst.
DISCLOSURE OF THE INVENTION
[0009] The present invention may be configured as a fuel cell
module for a vehicle of the invention is a fuel cell module for a
vehicle including a stacked-cell body which is provided with
electric output terminals for taking electric power from stacked
power generating cells, and a metallic casing which has an
insulation layer on its inner surface and accommodates the
stacked-cell body, wherein an insulator which is thicker than the
insulation layer is disposed between the insulation layer and the
electric output terminals.
[0010] The present invention further provides a fuel cell module
for a vehicle of the invention is a fuel cell module for a vehicle,
including a stacked-cell body which is provided with a positive
electric output terminal having a voltage higher than a ground
potential and a negative electric output terminal having a voltage
lower than the ground potential, and a metallic casing which has an
insulation layer on its inner surface, accommodates the
stacked-cell body and has the same potential as the ground
potential, wherein an insulator thicker than the insulation layer
is disposed between the insulation layer and the individual
electric output terminals.
[0011] In the fuel cell module for a vehicle of the invention, the
stacked-cell body is preferably disposed at the front end of the
vehicle, with the power generating cells stacked in the
longitudinal direction of the vehicle and the electric output
terminals located on the vehicle front side; the insulator is
preferably made of insulating rubber or an insulating resin; the
insulator is preferably an insulating cover for covering the
electric output terminals; the insulator is preferably an
insulating plate which is disposed on the inner surface of the
casing; and the insulating plate is preferably fixed to a
tightening member for the stacked-cell body.
[0012] The present invention may further be configured as a fuel
cell module for a vehicle of the invention is a fuel cell module
for a vehicle, including a stacked-cell body having power
generating cells stacked, and a metallic casing for housing the
stacked-cell body, wherein an insulator is disposed between the
metallic casing and a surface of the stacked-cell body opposite a
side face of the vehicle. In the fuel cell module for a vehicle of
the invention, an insulator is preferably disposed between the
metallic casing and individual surfaces, which are opposed to
individual side faces of the vehicle, of the individual
stacked-cell bodies which accommodate a plurality of the stacked
power generating cell bodies and are disposed on both side faces of
the vehicle; a thin insulating sheet thinner than the insulator is
preferably disposed between a plurality of the stacked power
generating cell bodies; the metallic casing has preferably an
insulation layer on its inner surface, and the insulator is thicker
than the insulation layer; and the insulating sheet is preferably
thicker than the insulation layer.
[0013] Application of the present invention makes it possible to
prevent short circuiting of the electric output terminals of the
fuel cell module for a vehicle or between the power generating
cells of the fuel cell module for the vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic plan view showing a fuel cell module
according to a first embodiment of the present invention installed
in a vehicle.
[0015] FIG. 2 is an explanatory view showing a connected state of
power generating cells of the fuel cell module according to the
first embodiment of the present invention.
[0016] FIG. 3 is a schematic elevation view of a fuel cell module
according to the first embodiment of the present invention mounted
in a vehicle.
[0017] FIG. 4 is a partial sectional view of a fuel cell module
including electric output terminals according to the first
embodiment of the present invention.
[0018] FIG. 5A is a perspective view of an insulating cover
according to the first embodiment of the present invention in an
open state.
[0019] FIG. 5B is a perspective view showing an assembled state of
an insulating cover according to the first embodiment of present
the invention.
[0020] FIG. 6A is an explanatory view showing a section of the
insulating cover attached to the electric output terminals of the
fuel cell module according to the first embodiment of the present
invention.
[0021] FIG. 6B is an explanatory view showing an insulating cover
attached to the electric output terminals of the fuel cell module
according to the first embodiment of the present invention.
[0022] FIG. 7 is a schematic elevation view showing an example of
deformation of a vehicle and a fuel cell module when the front of a
vehicle on which a fuel cell according to present invention is
involved in a collision with an object.
[0023] FIG. 8 is a schematic sectional view of a fuel cell module
according to another embodiment of the invention.
[0024] FIG. 9 is a schematic showing a sectional view of a fuel
cell module according to still another embodiment of the
invention.
[0025] FIG. 10 is a schematic plan view showing a vehicle-mounted
fuel cell module according to still another embodiment of the
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0026] Preferred embodiments of the invention will be described
with reference to the figures.
[0027] FIG. 1 is a schematic plan view of the front section of an
automobile (vehicle front section) in which is installed a fuel
cell module according to the first embodiment of the present
invention. In FIG. 1, a fuel cell module 11 is installed in a room
10 at the vehicle front section. The fuel cell module 11 has a
casing 12 in which a stacked-cell body 15 is housed. The casing 12
has a casing body 12a and a cover 14 and houses the stacked-cell
body 15 airtight. For the convenience of explanation, the cover 14
and insulating covers attached to individual electric output
terminals 21, 23 are omitted from the figure so that the
configuration of the stacked-cell body 15, cables, and the like
contained are visible.
[0028] The stacked-cell body 15 has a first cell stack 17 and a
second cell stack 18 which are stacked bodies of power generating
cells 16 which are plate-like unit cells, electrode plates 21a, 23a
which are stacked at one end of the individual cell stacks 17, 18,
and end plates 19, 20 which are arranged on both sides of the
individual electrode plates 21a, 23a. The individual cell stacks
17, 18 which are arranged in parallel are configured to include the
same number of power generating cells 16 and to generate the same
voltage. The stacked direction of each of the first cell stack 17
and the second cell stack 18 is a longitudinal direction of the
vehicle, and the individual cell stacks 17, 18 and the individual
electrode plates 21a, 23a are compressed in the stacked direction
by the metallic end plates 19, 20 which are arranged at their front
and rear ends and have a relatively large thickness (for example, a
thickness of about 15 mm).
[0029] As shown in FIG. 2, in the first cell stack 17 and the
second cell stack 18 the power generating cells 16 are stacked with
polarities directed to opposite directions from each other. The
first cell stack 17 has positive terminals directed to the vehicle
front and negative terminals directed to the vehicle rear shown in
FIG. 1, and the second cell stack 18 has negative terminals
directed to the vehicle front and positive terminals directed to
the vehicle rear shown in FIG. 1. The ends of the first cell stack
17 and the second cell stack 18 on the side of the end plate 20 are
electrically connected to each other. Thus, the cell stacks 17, 18
compose a series-connected unit cell body of one power generating
cell 16 and provides a desired high voltage. The electrically
connected ends on the side of the end plate 20 are also connected
to the vehicle body, and their connection point is a ground
electric potential.
[0030] Therefore, the electric output terminal 21 of the electrode
plate 21a stacked at the end on the side of the end plate 19 of the
first cell stack 17 and the second cell stack 18 becomes a positive
electric output terminal having a voltage higher than the ground
electric potential, and the electric output terminal 23 of the
electrode plate 23a stacked on the second cell stack 18 becomes a
negative electric output terminal having a voltage lower than the
ground electric potential. The metallic casing 12 mounted in the
vehicle body becomes the ground electric potential.
[0031] While the end plates 19, 20 are fixed to the casing 12, the
dimensions of the cell stacks 17, 18 may change in the stacked
direction due to thermal expansion, contraction, or the like
resulting from temperature changes. Accordingly, stacked disc
springs (not shown) are assembled between the end plate 19 and the
electrode plate 21a and between the end plate 19 and the electrode
plate 23a to configure such that the power generating cells 16
which are unit cells configuring the cell stacks 17, 18 are always
press-contacted mutually by a proper force.
[0032] Within the casing 12 are sheathed cables 31, 33 for bringing
electric power from the stacked-cell body 15, a relay 25 which cuts
off a harness 35 and an electric circuit, the electric circuit, a
distributor (not shown), and the like. The relay 25 and the
electric output terminals 21, 23 which are a positive terminal and
a negative terminal are electrically connected through the flexible
sheathed cables 31, 33. The sheathed cables 31, 33 are fixed to the
positive and negative electric output terminals 21, 23 and the
terminals of the relay 25 by a bolt 26 and a nut 28.
[0033] A service plug 27 is attached to a position on the side and
rear side face of the casing 12, while the relay 25 and the service
plug 27 are electrically connected by the sheathed harness 35 for
each positive and negative terminal. Additionally, a power output
cable 37 is extended from the service plug 27 to the exterior of
the casing 12, and the harness 35 and the power output cable 37 are
electrically connected by the service plug 27.
[0034] With the configuration as described, electric power
generated by the fuel cell module 11 is output from the power
output cable 37 via the relay 25 and the service plug 27, and the
output can be cut off by the relay 25 and the service plug 27. The
relay 25 controls electrical flow between the terminals to which
the sheathed cables 31, 33 are connected and the terminal connected
to the harness 35 for the positive and negative terminals,
according to an externally-supplied control signal. For example,
the relay 25 is normally kept ON when the vehicle is traveling or
the like, and it is possible to output from the fuel cell module
11. Meanwhile, the relay is switched OFF according to a control
signal which is issued when a crash sensor (not shown) detects a
collision or the like of the own vehicle, and the output from the
fuel cell module 11 is cut off.
[0035] Meanwhile, the end plate 20 of the stacked-cell body 15 is
provided with a fuel inlet pipe 41 and an exhaust gas discharge
pipe 43. These pipes are arranged on the rear side under the
vehicle front room 10 where the casing 12 is disposed.
[0036] Additional components for operating the vehicle, such as a
radiator 51 or the like, are housed in the vehicle front room 10 in
addition to the casing 12 in which the stacked-cell body 15 is
housed, and front wheels 57 are fitted on both sides. The radiator
51 is disposed between the casing 12 and a front grill 53 at the
front of the room 10, and configured to be connected to a coolant
path circulating within the fuel cell module 11, in order to enable
cooling of the liquid coolant circulating through the coolant
path.
[0037] FIG. 3 is a schematic elevation view showing the fuel cell
module 11 installed in the vehicle front room 10. As shown in FIG.
3, the vehicle front room 10 has a shape which protrudes beyond the
vehicle front. Additionally, a vehicle interior 63 where a steering
wheel 59 and the like are installed and the area in the room 10 are
separated by a partition wall 61.
[0038] The fuel cell module 11 is installed near the center of the
room 10 and fixed to the vehicle body such that the power
generating cells 16 are stacked in the longitudinal direction of
the vehicle. The stacked-cell body 15 is housed in the casing body
12a. The casing 12 is made airtight by fixing the cover 14 to the
top of the casing body 12a. The casing body 12a and the cover 14
have an insulation layer 13 on their inner surfaces. The individual
electrode plates 21a, 23a of the positive terminal and the negative
terminal are stacked at the front of the stacked-cell body 15, and
the individual electrode plates 21a, 23a are provided with the
individual electric output terminals 21, 23 which are projections
projecting toward the vehicle top. Further, the cover 14 is formed
to have a bulged section in the area towards the front which covers
the individual electric output terminals 21, 23, so as to provide a
necessary clearance for these individual electric output terminals
21, 23.
[0039] As shown in FIG. 4, the individual electrode plates 21a, 23a
of the positive terminal and the negative terminal are configured
to be insulated from each other by a middle partition, and the
individual electric output terminals 21, 23 of the positive
terminal and the negative terminal are arranged to project. The
cover 14 of the casing 12 bulges upward from the connected surface
to provide a clearance for the individual electric output terminals
21, 23 as shown in the figure, and the insulation layer 13 is
disposed on the inner surface. The insulation layer 13 may be
provided using an insulation coating or the like. The individual
electric output terminals 21, 23 are square plates formed of a
conductive material such as copper or the like and have a hole
formed in their center. Meanwhile, the sheathed cables 31, 33 which
take electric power from the individual electric output terminals
21, 23 are flexible cables, and connecting terminals 29, 30 for
connection with the individual electric output terminals 21, 23 are
attached to one ends of the individual sheathed cables 31, 33. The
connecting terminals are made of a metal plate having its leading
end bent into an L shape and a hole for fixing the center. The bolt
26 is inserted through each of the holes formed in the centers of
the individual electric output terminals 21, 23 and each of the
holes formed in the connecting terminals 29, 30 and fixed by
tightening the nut 28. Thus, the connecting terminals 29, 30 of the
sheathed cables 31, 33 are attached and fixed to the individual
electric output terminals 21, 23.
[0040] Insulating covers 22, 24 are attached as insulators to cover
the external surfaces of the individual electric output terminals
21, 23 and the connecting terminals 29, 30 fixed to the individual
electric output terminals 21, 23. The insulating covers 22, 24 are
preferably formed of a material such as rubber having sufficient
thermal conductivity. As shown in FIG. 5A, the individual
insulating covers 22, 24 are configured of, for example, nut sides
22a, 24a and bolt sides 22b, 24b of the individual electric output
terminals 21, 23. One end each of the insulating covers is
integrally formed and the other end is openable, so that they are
easily attached to the individual electric output terminals 21, 23.
The insulating covers 22, 24 are configured to have inner surfaces
with recessed portions to conform with the individual shapes of the
electric output terminals 21, 23; the connecting terminals 29, 30;
the bolt 26 and the nut 28 so as to cover these components, and the
exterior surface externally protruded according to the recessed
portions so the insulator will have a substantially uniform
thickness. Tightening bands 32, 34 are attached on the side of an
opening. The tightening bands 32, 34 have a hole in one end and a
hook attached to the other end. As shown in FIG. 5B, after the
insulating covers 22, 24 are attached to the individual electric
output terminals 21, 23 and the connecting terminals 29, 30, the
holes of the tightening bands 32, 34 are caught by the hooks to
firmly fix the individual insulating covers 22, 24 to the
individual electric output terminals 21, 23.
[0041] FIG. 6A and FIG. 6B show sectional views of the insulating
covers 22, 24 which are attached to the outside surfaces of the
individual electric output terminals 21, 23 and the connecting
terminals 29, 30. As shown in FIG. 6A, when the individual
insulating covers 22, 24 are fixed to the individual electric
output terminals 21, 23 by the pressure of the tightening bands 32,
34; the inner surfaces of the individual insulating covers 22, 24
are firmly attached to the individual surfaces of the individual
electric output terminals 21, 23, the connecting terminals 29, 30,
the bolt 26 and the nut 28 by virtue of the elasticity of the
material rubber. Therefore, heat from the individual electric
output terminals 21, 23 which are also heat generators is
transmitted to the individual insulating covers 22, 24 and readily
radiated from the outside surfaces. Thus, the individual electric
output terminals 21, 23 can be prevented from having an increase in
temperature. In addition, because the insulating covers 22, 24 have
a substantially equal thickness with respect to the individual
electric output terminals 21, 23 and the connecting terminals 29,
30, heat radiated from the individual surfaces is not dissipated,
heat from the individual electric output terminals 21, 23 can be
radiated evenly from the entire circumference, and temperature
variations can be eliminated.
[0042] As shown in FIG. 6A and FIG. 6B, because the insulating
covers 22, 24 have a thickness greater than that of other
insulation coating or the like, when they receive an outside
impact, they can absorb the impact and reduce an occurrence of a
damage to the insulating covers 22, 24 by virtue of their
thickness, so that the insulated states of the individual electric
output terminals 21, 23 can be maintained.
[0043] Next, deformation of the room 10 and the fuel cell module 11
and the retention of the insulated states of the individual
electric output terminals 21, 23 in the event that the front of a
fuel cell vehicle installed with the fuel cell module 11 configured
as described above comes into collision with another object will be
described.
[0044] As shown in FIG. 7, when the front of the fuel cell vehicle
collides with another object, a crash sensor (not shown) detects
the collision and turns off the relay 25 to cut off the output from
the fuel cell module 11. A bumper 55 which is mounted on the front
of the vehicle is pushed toward the vehicle rear as a result of the
front-end collision. In addition, the room 10 including the front
grill 53 of the vehicle is shortened due to compression deformation
and the radiator 51 between the front grill 53 and the fuel cell
module 11 is displaced rearwards and pushed against the casing body
12a of the fuel cell module 11 and the cover 14. Because the casing
body 12a and the cover 14 are formed of, for example, a metal such
as an aluminum alloy or the like, their front parts are crushed by
plastic deformation. At this time, the cover 14 is deformed to be
compressed in the longitudinal direction of the vehicle and the
swelled portion on the top of the cover 14 is also deformed
downward, towards the individual electric output terminals 21, 23.
Thus, the deformation causes the inner surface of the cover 14 to
come into contact with the insulating covers 22, 24 which are
attached to the exteriors of the individual electric output
terminals 21, 23. As described above, the electric output terminal
21 is a positive electric output terminal having a voltage higher
than ground electric potential, and the electric output terminal 23
is a negative electric output terminal having a voltage lower than
the ground electric potential. Because the cover 14 and the casing
body 12a are made of metal and provide ground potential, such
deformation will likely cause damage to the insulation between the
metallic cover 14 and one or both of the metallic electric output
terminals 21, 23, such that the cover 14 will come into direct
contact with one or both the electric output terminals 21, 23, in
which event a short circuit will result due to the voltage
difference between the ground electric potential and the positive
voltage or between the ground electric potential and the negative
voltage. Even if the electric output of the fuel cell module 11 is
cut off by the relay 25, the individual electrode plates 21a, 23a
of the fuel cell module 11 are in states of high positive voltage
and negative voltage, so that, when a short circuit as described
above occurs, an abnormal electric potential is generated in the
power generating cells 16, and a catalyst is deteriorated by, for
example, sintering of the catalyst, oxidation of supported carbon,
or the like. In addition, if the insulation between both the
electric output terminals 21, 23 and the cover 14 which is a
conductor is damaged, a short circuit may result between the
electric output terminals 21, 23 through the cover 14. Because the
resulting voltage difference is twice that of the difference
between the cover 14 and one of the electric output terminals 21,
23, and the result damage to the catalyst is significantly
greater.
[0045] However, because in the present embodiment the individual
electric output terminals 21, 23 o have thick rubber insulating
covers 22, 24, contact of the cover 14 to the exterior surfaces of
the individual electric output terminals 21, 23 is far less likely
to damage the insulation layer 13 which is formed of a soft
insulation coating, and the metallic cover 14 and the individual
electric output terminals 21, 23 are therefore unlikely to contact
each other. Therefore, short circuiting between the cover 14 and
the individual electric output terminals 21, 23 or between the
electric output terminals 21 and 23 can be effectively prevented,
so that an advantage is achieved in that the deterioration of the
catalyst as a result of abnormal electric potentials in the power
generating cells 16, for example, sintering of the catalyst,
oxidation of supported carbon, or the like, can be prevented.
[0046] Even when the insulation layer 13 on the inner surface of
the cover 14 is formed of an insulation coating or the like and
cannot respond to a large plastic deformation of the metallic cover
14 and the coated surface is separated from the metallic surface to
expose the metallic surface toward the inner surface of the cover
14, an advantage is still achieved in that the insulating covers
22, 24 attached to the individual electric output terminals 21, 23
are able to maintain an insulated state to effectively prevent the
electric output terminals from short circuiting.
[0047] A second embodiment will next be described with reference to
FIG. 8. Corresponding components which function in the same manner
as those of the previous embodiment are denoted by the same
reference numerals as those used in the previous embodiment, and
their detailed descriptions will not be repeated. The fuel cell
module 11 of this embodiment has a resin insulating plate 45
attached to the inner surface of the cover 14 of the casing 12,
which houses the stacked-cell body 15, with resin insulating bolts
47. It is sufficient that the insulating plate 45 be assembled
between the electric output terminals 21, 23 and the insulation
layer 13 on the inner surface of the cover 14, and its width may be
configured to be equal to the total width of the fuel cell module
11 or equal to just the electric output terminal portion. And, as
the resin insulating bolts 47 for attachment, it is configured to
enable to prevent a short circuit between the cover 14 and the
electric output terminals 21, 23 or between the electric output
terminals 21 and 23 via the cover 14, even if the insulating bolts
47 come into contact with the electric output terminals 21, 23.
[0048] The resin insulating plate 45 has a thickness greater than
that of the insulation layer 13 which is disposed on the inner
surface of the cover 14, and is configured to prevent, by virtue of
its thickness, short circuiting between the individual electric
output terminals 21, 23 and the metallic portions of the cover 14,
even in the even of a collision deforming the bulge in the cover
14.
[0049] Referring to FIG. 9, another embodiment will be described.
Corresponding components which function in the same manner as those
of either of the previous embodiments are denoted by the same
reference numerals as those used in the previous embodiment, and
their detailed descriptions will not be repeated. In this
embodiment, a resin insulating plate 46 is assembled to a
tightening member for tightening the end plate 19 of the
stacked-cell body 15 housed in the casing 12 or the power
generating cells 16, such as a tension plate, which is not shown.
In this embodiment, the insulating plate 46 is fixed to the end
plate 19 with the insulating bolts 48. The insulating plate 46 is
assembled between the electric output terminals 21, 23 and the
insulation layer 13 formed on the inner surface of the cover 14,
and formed to be thicker than the insulation layer 13 so that, even
if the bulge of the cover 14 is deformed towards the electric
output terminals 21, 23 as a result of a collision or the like, the
metallic portion of the cover 14 will not come into contact with
the electric output terminals 21, 23, and a short circuit will not
occur. The insulating plate 46 may be configured to be attached to
the entire face in the width direction of the fuel cell module 11,
or to just the electric output terminals 21, 23. Similar as in the
previous embodiments, this embodiment also produces an advantageous
effect that short circuiting between the cover 14 and the
individual electric output terminals 21, 23 and between the
electric output terminals 21 and 23 can be effectively
prevented.
[0050] Although in the examples described with reference to FIG. 8
and FIG. 9, insulating covers 22, 24 are not provided for the
individual electric output terminals 21, 23, it is also preferable
that the insulating covers 22, 24 are attached in addition to the
resin insulating plates 45, 46 similar to the embodiment shown in
FIG. 1 to FIG. 6.
[0051] Referring to FIG. 10, a still further embodiment will be
described below. Corresponding components which function in the
same manner as those of the previous embodiments are denoted by the
same reference numerals as those used in the previous embodiment,
and their detailed descriptions will not be repeated. In this
embodiment, the first and second cell stacks 17, 18 configuring the
stacked-cell body 15 are housed in the casing 12 of the fuel cell
module 11. As shown in FIG. 10, an insulating plate 49 is disposed
between the casing 12 and a left side face of the cell stack 17,
which faces towards one side of the vehicle. Also as shown in FIG.
10, another insulating plate 49 is also disposed between the casing
12 and a right side face of the cell stack 18, which faces towards
another side of the vehicle, and an insulating sheet 50 is disposed
between the first and second cell stacks 17 and 18. The insulating
plate 49 may be formed of a rubber plate or a resin plate. The
insulating sheet may be formed of a rubber plate or a resin plate
which is thinner than the insulating plate 49. The insulating plate
49 and the insulating sheet 50 may be attached to the casing 12
with insulating bolts or the like or may be configured to attach to
the individual cell stacks 17, 18.
[0052] The present invention may be configured such that the
insulation layer is provided by insulation coating on the inner
surface of the casing 12, or such that the insulating plate 49 is
thicker than the insulation layer.
[0053] By employing a configuration as described above, there is
produced an effect that, in the event of a side collision,
occurrence short circuiting between the power generating cells via
the casing due to the deformation of the casing can be effectively
prevented. Further, by providing a thick insulator on the side face
which is easily deformed to enhance the insulating property of the
side face, there is produced an effect that the insulator can be
reduced.
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