U.S. patent application number 09/906278 was filed with the patent office on 2002-01-17 for power supply unit.
This patent application is currently assigned to Matsushita Electric Industrial Co., Ltd.. Invention is credited to Kimoto, Shinya, Kobayashi, Takaki, Watanabe, Ko.
Application Number | 20020005708 09/906278 |
Document ID | / |
Family ID | 18711317 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020005708 |
Kind Code |
A1 |
Kobayashi, Takaki ; et
al. |
January 17, 2002 |
Power supply unit
Abstract
A power supply unit capable of simplifying the structure of a
battery case and improving the cooling efficiency by increasing the
cross sectional area of a coolant passage. A power supply unit
includes a battery case; a plurality of battery modules disposed in
parallel, each battery module is composed of three cells connected
in series in a row, and the front end and the rear end of the
battery module are held by the front part and the rear part of the
battery case; a cooling fan for forcing a cooling air to flow in
the passage between the neighboring battery modules; a shielding
plate for shielding the cooling air from the battery module, which
is placed at the upstream side of the passage and; a rectifying fin
for increasing the flow rate of the cooling air, which is placed at
the downstream side of the passage.
Inventors: |
Kobayashi, Takaki; (Aichi,
JP) ; Kimoto, Shinya; (Aichi, JP) ; Watanabe,
Ko; (Aichi, JP) |
Correspondence
Address: |
Merchant & Gould P.C.
P.O. Box 2903
Minneapolis
MN
55402-0903
US
|
Assignee: |
Matsushita Electric Industrial Co.,
Ltd.
|
Family ID: |
18711317 |
Appl. No.: |
09/906278 |
Filed: |
July 16, 2001 |
Current U.S.
Class: |
320/107 |
Current CPC
Class: |
H01M 10/651 20150401;
H01M 50/20 20210101; H01M 10/643 20150401; H01M 10/6566 20150401;
H01M 10/6563 20150401; H01M 50/107 20210101; Y02E 60/10 20130101;
H01M 10/613 20150401; H01M 10/617 20150401 |
Class at
Publication: |
320/107 |
International
Class: |
H02J 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 17, 2000 |
JP |
2000-215974 |
Claims
What is claimed is:
1. A power supply unit comprising a battery case, a plurality of
battery modules disposed in parallel, each battery module being
composed of three cells or less connected in series in a row, and
the front end and the rear end of the battery module being held by
a front part and a rear part of the battery case, a cooling system
for forcing a coolant to flow in a passage between the neighboring
battery modules, and a shielding system for shielding the coolant
from the battery module, which is placed at an upstream side of the
passage.
2. The power supply unit according to claim 1, further comprising a
means for increasing the flow rate of the coolant, placed at a
downstream side of the passage.
3. The power supply unit according to claim 1, wherein a detachable
first constraint plate is further provided at the front part of the
battery case and the front end of the battery module is held by the
first constraint plate.
4. The power supply unit according to claim 3, wherein an air inlet
port for drawing the coolant into the battery case from the outside
is provided on the first constraint plate, and the shielding means
for shielding the coolant from the battery module are integrated
into the first constraint plate with the air inlet port sandwiched
between the shielding means.
5. The power supply unit according to claim 1 or 4, wherein the
means for shielding the coolant from the battery module is provided
approximately in parallel to the battery module while protruding
into the battery case.
6. The power supply unit according to claim 1 or 4, wherein the
following relationship is satisfied:L/2<m.ltoreq.L,where L
denotes a length of the cell, and m denotes a length of the
shielding system for shielding the coolant from the battery
module.
7. The power supply unit according to claim 1, wherein a second
constraint plate is provided at the rear part of the battery case
and the rear end of the battery module is held by the second
constraint plate.
8. The power supply unit according to claim 7, wherein an exhaust
port for exhausting the coolant to the outside from the inside of
the battery case is provided in the second constraint plate, and a
means for increasing the flow rate of the coolant is integrated
into the second constraint plate.
9. The power supply unit according to claim 2 or 8, wherein the
means for increasing the flow rate of the coolant is a wedge-shaped
rectifying fin protruding into the battery case.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a power supply unit
including a number of cells connected in series and being used for
an electric vehicle such as a pure electric car, etc. In more
detail, the present invention relates to a radiator of cells
constituting the power supply unit.
[0003] 2. Description of the Prior Art
[0004] In general, in an electric vehicle such as a pure electric
car, etc., in order to supply a motor etc. with electric power for
driving a vehicle, a power supply unit including a number of cells
connected in series is mounted. In this way, a number of cells
connected in series are used as a power supply unit of an electric
vehicle, it is necessary to dispose a plurality of cells densely
from the viewpoint of space efficiency, etc. Therefore, plural rows
of storage batteries in which a plurality of cells arranged in a
row and electrically connected in series are disposed in
parallel.
[0005] When a plurality of cells are disposed densely as mentioned
above, the temperature in the power supply unit is raised due to
heat generation, Joule heat or the like of the cells, thus raising
the temperature of each cell. Therefore, conventionally, a method
for suppressing the temperature rise of each cell by allowing a
coolant such as air, etc. to circulate between cells has been
employed.
[0006] However, the conventional cooling method increases the
difference in temperature between cells, which may lead to a
variation of the battery performance, for example, charge-discharge
capacity or life, etc., between cells. Therefore, the reliability
as a power supply unit was low.
[0007] In order to reduce the difference in temperature between
cells, JP10 (1998)-3950proposes a power supply unit including a
group of storage batteries in which plural rows of storage
batteries including a plurality of cells connected in series in a
row are disposed in parallel above and below and left and right of
a coolant passage for allowing a coolant to circulate between the
rows of the storage battery, wherein the coolant passage includes a
main coolant passage that is exposed to the cells within the same
storage battery row and a sub-coolant passage whose upstream side
is separated from the storage battery row and whose downstream end
is connected to the main coolant passage at the position
corresponding to the midstream or downstream end of the storage
battery row. With this configuration, the following effects can be
obtained. Namely, the temperature of the coolant circulating in the
main coolant passage is increased by the endothermic from the cells
of the upstream of the storage battery rows and the cooling
efficiency at the midstream and downstream is deteriorated.
However, in the midstream and the downstream of the main coolant
passage, by combining the coolant circulating in the main coolant
passage with a low temperature coolant, the temperature of the
coolant is lowered. Thus, the cooling efficiency of the cells at
the further downstream can be enhanced to reduce the difference in
temperatures within the storage battery row.
[0008] However, there is a problem in that with the configuration
of the power supply unit suggested in JP10 (1998)-3950A, the
structure of the case housing the storage battery row (battery
module) becomes complicated. Namely, a battery holding member for
holding the storage battery row (battery module) is necessary, and
also an idea for forming a sub-coolant passage, or for connecting
the main coolant passage with the sub-coolant passage at the
position corresponding to the midstream or downstream of the
storage battery row (battery module) is necessary. Furthermore,
since the cross-sectional area of the passage is small, the
pressure loss of the coolant is increased, thus deteriorating the
cooling efficiency.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide a power
supply unit in which the structure of the battery case can be
simplified and a cross sectional area of the passage is increased
to improve the cooling efficiency.
[0010] In order to achieve the above-mentioned object, a power
supply unit according to the present invention includes; a battery
case, a plurality of battery modules disposed in parallel, each
battery module being composed of three cells or less connected in
series, and the front end and the rear end of the battery module
being held by the front part and the rear part of the battery case,
a cooling system for forcing a coolant to flow in a passage between
the neighboring battery modules, and a shielding system placed at
the upstream side of the coolant passage and shielding the coolant
from the battery module. According to the configuration of this
power supply unit, since each battery module is composed of three
cells or less, when the front end and the rear end of the battery
module are held by the front part and the rear part of the battery
case, the cells positioned in the middle part are held securely by
the cells positioned at both ends. Consequently, it is possible to
prevent the connection parts of the battery module from being
deviated or detached from each other due to the vibration from the
outside. Therefore, since a battery holding member other than the
holding means for the front part and the rear part of the battery
case is not required, the structure of the battery case can be
simplified. Furthermore, for the same reason, since a
cross-sectional area of the passage between the neighboring battery
modules can be increased, it is possible to reduce the pressure
loss of the coolant and to improve the cooling efficiency.
Furthermore, since the means for shielding the coolant from the
battery module is provided at the upstream side of the coolant
passage, the heat amount that the coolant entering the passage
between the neighboring battery modules within the battery case can
absorb from the cell placed at the upstream side is reduced.
Therefore, since the temperature of the coolant is not increased
due to the heat of the cell placed at the upstream side of the
coolant passage, it is possible to cool the cell at the midstream
and downstream efficiently. In particular, since the battery module
is composed of three cells or less, as compared with the battery
module composed of four cells or more, it is possible to reduce the
variation in temperatures between cells. Therefore, the temperature
difference between cells within the battery module can be reduced.
Thus, it is possible to suppress the variation of the battery
performance such as charge/discharge capacity or life, etc. As a
result, the reliability as a power supply unit can be enhanced.
[0011] Furthermore, it is preferable that the configuration of the
power supply unit of the present invention includes means for
increasing the flow rate of the coolant, the means being placed at
the downstream side of the coolant passage. With this preferable
configuration, it is possible to improve the cooling efficiency of
the cells positioned at the downstream side of the coolant passage.
Furthermore, in this case, it is preferable that the means for
increasing the flow rate of the coolant is a wedge-shaped
rectifying fin protruding into the battery case.
[0012] Furthermore, in the power supply unit of the present
invention, it is preferable that a detachable first constraint
plate is further provided at the front part of the battery case and
the front end of the battery module is held by the first constraint
plate. According to this configuration, after the battery module is
housed in the battery case, the battery modules can be held in the
battery case. Furthermore, in this case, it is preferable that an
air inlet port is provided in the first constrained plate, which is
placed between the neighboring battery modules and draws the
coolant into the battery case from the outside, and the means for
shielding the coolant from the battery module is integrated into
the first constraint plate with the air inlet port sandwiched
therebetween. According to this preferable configuration, since the
means for shielding the coolant from the battery module is
integrated into the first constraint plate, the number of the
components can be reduced.
[0013] Furthermore, it is preferable in the power supply unit of
the present invention that the means for shielding the coolant from
a battery module is provided approximately in parallel to the
battery modules while protruding into the battery case.
[0014] Furthermore, it is preferable that the power supply unit of
the present invention satisfies the relationship:
L/2<m.ltoreq.L, where L denotes a length of the cell, and m
denotes a length of the shielding system for shielding the coolant
from the battery module. According to this preferable
configuration, heat exchange amount can be reduced.
[0015] Furthermore, in the power supply unit of the present
invention, it is preferable that a second constraint plate is
further provided at the rear part of the battery case and the rear
end of the battery module is held by the second constraint plate.
Furthermore, in this case, it is preferable that an exhaust port
for exhausting the coolant to the outside from the inside of the
battery case is provided in the second constraint plate, and a
means for increasing the flow rate of the coolant is integrated
into the second constraint plate. According to this preferable
configuration, since the means for increasing the flow rate of the
coolant is integrated into the second constraint plate, the number
of the components can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view showing a power supply unit
according to an embodiment of the present invention.
[0017] FIG. 2 is a cross sectional view taken on line A-A of FIG.
1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Hereinafter, the present invention will be described more
specifically by way of embodiments.
[0019] FIG. 1 is a perspective view showing a power supply unit
according to an embodiment of the present invention; and FIG. 2 is
a cross sectional view taken on line A-A of FIG. 1.
[0020] As shown in FIGS. 1 and 2, the power supply unit 1 includes
a battery case 2, a plurality of battery modules 3, an air
introduction duct 4, an air exhaust duct 5, and a cooling fan 6.
The battery modules 3 are housed in the battery case 2, and each
battery module is composed of a plurality of cells connected in
series. The air introduction duct 4 introduces air (cooling air) as
a coolant into the battery case 2 from the outside, and the air
exhaust duct 5 exhausts a cooling air from the inside of the
battery case 2 to the outside. The cooling fan 6 is provided in the
air exhaust duct 5, and forces the cooling air to circulate in the
battery case 2.
[0021] The battery module 3 includes three cells 7, for example,
nickel-hydride secondary cells, connected in series in a row via
connection rings 8. A joint nut 9 is spot-welded to the connection
ring 8 attached to a positive terminal of the battery module 3.
Likewise, a joint nut 10 is spot-welded to the connection ring 8
attached to a negative terminal of the battery module 3.
[0022] The battery case 2 has an upper stage and a lower stage.
Both in the upper stage and lower stage, a plurality of battery
modules 3 are arranged in parallel.
[0023] In the front part of the battery case 2, a first constraint
plate 11 is attached detachably. The first constraint plate 11 is
provided with nut through holes 12 for allowing the nut 9 placed at
the positive terminal or the nut 10 placed at the negative terminal
to passage through and an air inlet port 13 placed in the middle
part between the upper and lower nut through holes 12. Furthermore,
at the upper edge and lower edge of the air inlet port 13, a couple
of shielding plates 14, which are approximately in parallel with
each other, are integrated into the first constraint plate 11 while
protruding into the battery case 2. Thereby, the cooling air
entering the passage between the upper and lower battery modules 3
from the air inlet port 13 is shielded by the shielding plates 14
so that the amount of heat absorbed from the first cell 7 is
reduced. In this case, it is desirable that the following
relationship is satisfied: L/2<m.ltoreq.L (wherein L denotes a
length of the cell 7, and m denotes a length of the shielding plate
14). When the above-mentioned relationship is satisfied, it is
possible to lower the heat exchange amount. Furthermore, by
integrating the shielding plate 14 into the first constraint plate
11, it is also possible to reduce the number of the components. The
upper and lower parts of the first constraint plate 11 are provided
with step parts so that the upper and lower ends of a fixing plate
21 provided with a plurality of bolt through holes can be attached
into contact therewith. Thus, the bolt 20 is welded to the nut 9
and the nut 10 via the fixing plate 21.
[0024] In the rear part of the battery case 2, the second
constraint plate 15 is fixed. Similar to the first constraint plate
11, the second constraint plate 15 is provided with a nut through
hole 16 for allowing the nut 9 placed at the positive terminal of
the battery module 3 or the nut 10 placed at the negative terminal
of the battery module 3 to passage through and a large number of
exhaust ports 17. The circumference of the nut through hole 16 is
provided with a step part so that the circumference of a washer 19
can be placed into contact with thereof. Thus, the bolt 20 is
tightened to the nut 9 and nut 10 via the washer 19. Furthermore,
in the middle part between the upper and lower nut through holes
16, a wedge-shaped rectifying fin 18 is integrated into the second
constraint plate 15 while protruding into the battery case 2.
Thereby, since a cross sectional area of a passage between third
cells 7 is reduced, the flow rate of the cooling air entering from
the air inlet port 13 is increased around the third cell 7. In this
case, by integrating the rectifying fin 18 into the second
constraint plate 15, it is possible to reduce the number of
components.
[0025] Next, a method for assembling the power supply unit 1 having
the above-mentioned structure will be described briefly.
[0026] First, the battery modules 3 are inserted into the battery
case 2 from the front part of the battery case 2 with the
polarities alternated, and then the nut 9 placed at the positive
terminal of the battery module 3 and the nut 10 placed at the
negative terminal of the battery module 3 are allowed to passage
through the nut through hole 16 formed on the second constraint
plate 15. Next, the first constraint plate 11 is inserted into the
battery case 2 from the front part and the nut 10 placed at the
negative terminal of the battery module 3 and the nut 9 placed at
the positive terminal of the battery module 3 are allowed to
passage through the nut through hole 12 formed on the first
constraint plate 11. Next, a bolt 20 is tightened temporarily with
respect to the nuts 9 and 10 passing through the nut through hole
16 of the second constraint plate 15 via the washer 19, and at the
same time, the bolt 20 is tightened temporarily with respect to the
nuts 10 and 9 passing through the nut through hole 12 of the first
constraint plate 11 via the fixing plate 21. Next, all bolts are
tightened firmly, and a plurality of battery modules 3 are housed
in a state in which they are fixed in the battery case 2.
[0027] Next, the air introducing duct 4 is attached to the front
part of the battery case 2, and the air exhaust duct 5 equipped
with a cooling fan 6 is attached to the rear part of the battery
case 2. Thus, it is possible to obtain a power supply unit 1
including a large number of cells 7 connected in series and
equipped with a radiator.
[0028] As mentioned above, in this embodiment, since each battery
module 3 is composed of three cells 7, when the positive terminal
and negative terminal are held in the front part and rear part of
the battery case 2, the cell 7 placed in the middle is secured
reliably by the cells placed on both ends. As a result, it is
possible to prevent the connecting part (connection ring 8) of the
battery modules 3 from being deviated or detached due to vibration
from the outside. Therefore, since a battery holding member other
than the holding means for the front part and the rear part of the
battery case 2 is not required, the structure of the battery case 2
can be simplified. Furthermore, for the same reason, since the
cross sectional area of the passage between the upper battery
module and the lower parts of the battery module can be increased,
it is possible to improve the cooling efficiency by reducing the
pressure loss of the coolant.
[0029] Next, a method for radiating heat from the cell 7 in the
power supply unit 1 having the above-mentioned structure will be
described.
[0030] When a cooling fan 6 operates, air (cooling air) is
introduced into the battery case 2 from the outside through the air
introducing duct 4 attached to the front part of the battery case 2
and the air inlet port 13 formed in the first constraint plate 11.
The cooling air introduced into the battery case 2 flows toward the
second constraint plate 15 placed at the rear part of the battery
case 2 through the passage between the upper and lower battery
modules 3. The cooling air reaching to the rear part of the battery
case 2 is exhausted to the outside through the exhaust port 17
formed on the second constraint plate 15 and the air exhaust duct
5.
[0031] In this case, at the upper edge and the lower edge of the
air inlet port 13, a couple of shielding plates 14 are provided
approximately in parallel while protruding into the battery case 2.
Thus, the cooling air entering from the air inlet port 13 to the
passage between the upper and lower battery modules is shielded by
the shielding plates 14. Thus, the amount of heat absorbed from the
first cell 7 is reduced. Therefore, since the temperature of the
cooling air is not increased due to the heat from the first cell 7,
the second and third cells 7 can be cooled efficiently by the
cooling air. In particular, in this embodiment, since each battery
module 3 is composed of three cells 7, as compared with the case
where each battery module is composed of four cells 7 or more, it
is possible to reduce the variation of temperature between the
cells 7.
[0032] Furthermore, in the middle part between the upper and lower
nut through holes 16 of the second constraint plate 15, a
wedge-shaped rectifying fin 18 is provided while protruding into
the battery case 2. Therefore, the flow rate of the cooling air
entering from the air inlet port 13 is increased around the third
cell 7 by the rectifying fin 18. Therefore, it is possible to
improve the cooling efficiency of the third cell 7.
[0033] Therefore, since it is possible to reduce the difference of
temperature between the cells 7 in the battery module 3, it is
possible to suppress the variation of the battery performance such
as charge/discharge capacity or life, etc. As a result, the
reliability of the power supply unit can be enhanced.
[0034] The invention may be embodied in other forms without
departing from the spirit or essential characteristics thereof. The
embodiments disclosed in this application are to be considered in
all respects as illustrative and not limitative, the scope of the
invention is indicated by the appended claims rather than by the
foregoing description, and all changes which come within the
meaning and range of equivalency of the claims are intended to be
embraced therein.
* * * * *