U.S. patent application number 09/437241 was filed with the patent office on 2002-03-07 for battery cell and battery using the same.
Invention is credited to INOUE, TAKEFUMI, MASUDA, HIDEKI, YOSHIDA, HIROAKI.
Application Number | 20020028374 09/437241 |
Document ID | / |
Family ID | 18099654 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020028374 |
Kind Code |
A1 |
YOSHIDA, HIROAKI ; et
al. |
March 7, 2002 |
BATTERY CELL AND BATTERY USING THE SAME
Abstract
A cell has a winding type power generating element, a cell case
for housing the winding type power generating element therein and a
safety valve formed at the lower end of the side wall of the
cell.
Inventors: |
YOSHIDA, HIROAKI; (KYOTO,
JP) ; INOUE, TAKEFUMI; (KYOTO, JP) ; MASUDA,
HIDEKI; (KYOTO, JP) |
Correspondence
Address: |
SUGHRUE MION ZINN & SEAS PLLC
2100 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20037
|
Family ID: |
18099654 |
Appl. No.: |
09/437241 |
Filed: |
November 10, 1999 |
Current U.S.
Class: |
429/94 ; 429/120;
429/53 |
Current CPC
Class: |
H01M 10/05 20130101;
H01M 2006/106 20130101; H01M 10/6555 20150401; H01M 10/613
20150401; H01M 10/643 20150401; H01M 50/50 20210101; Y02P 70/50
20151101; H01M 10/0431 20130101; H01M 50/3425 20210101; Y02E 60/10
20130101; H01M 6/10 20130101; H01M 6/42 20130101 |
Class at
Publication: |
429/94 ; 429/53;
429/120 |
International
Class: |
H01M 006/10; H01M
002/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 1998 |
JP |
PHEI.10-318485 |
Claims
What is claimed is:
1. A cell comprising a winding type power generating element; a
cell case for housing the winding type power generating element
therein; and a safety valve formed at a position inclusive of a tip
end of a mixture-applied area of at least one electrode of the
power generating element on a side wall of the cell case along a
winding axis direction of the power generating element.
2. The cell according to claim 1, wherein the winding type power
generating element is an over-cylindrical winding type power
generating element; the cell case is an elliptic-cylindrical cell
case; and the safety valve formed at the position inclusive of the
tip end of the mixture-applied area of at least one electrode of
the power generating element on an elliptic-cylindrical curved
surface of the side wall of the cell case along the winding axis
direction of the power generating element.
3. The cell case according to claim 1, wherein a height of the cell
along its side wall is 1.5 times or more as large as the most
narrow width of the cell case.
4. A battery comprising a plurality of the cells according to any
one of claims 1 to 3 are arranged with said tip end located on
their bottom side, and a cooling plate is arranged on their bottom
side and between adjacent cells.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a battery cell such as a
nonaqueous electrolytic secondary cell in which a winding-type
power-generating element is housed within a cell case, and a
battery (multiple-cell set) using it.
[0003] 2. Description of the Related Art
[0004] An explanation will be given of a conventional structure of
a large-scale large-capacity elliptic-cylindrical nonaqueous
secondary cell 1. As seen from FIG. 19, a power generating element
2 of the nonaqueous secondary cell is composed of a belt-shaped
electrolytic positive electrode 2a and a belt-shaped negative
electrode 2b which are wound in an elliptic-cylinder through
belt-shaped separators 2c. The positive electrode 2a has an area of
a mixture 2d of an active material and binder for the positive
electrode applied on the surface of an aluminum foil and another
area on which the mixture 2d is not applied and to which the
aluminum foil is exposed at the belt-shaped lower end of the foil.
The negative electrode 2b has an area of a mixture 2e of an active
material and binder for the negative electrode applied on the
surface of a copper foil and another area on which the mixture 2e
is not applied and to which the copper foil is exposed at the
belt-shaped upper end of the foil. These positive electrode 2a and
a negative electrode 2b are wound in a manner displaced
horizontally little by little so that the lower end of the positive
electrode 2a protrudes downward and the upper end of the negative
electrode 2b protrudes upward.
[0005] As seen from FIG. 20, a negative electrode collector 9 is
fixedly connected to the upper end of the negative electrode 2b of
the power generating element 2 which protrudes upwards. The
negative electrode collector 9 is made by stamping a copper alloy
plate and folded to form slits. The copper foils exposed to the
upper ends of the negative electrodes 2b are inserted in and
fixedly connected to the respective slits by clamping or welding. A
negative electrode terminal 5 of a copper alloy is fixedly
connected to the negative electrode collector 9 by clamping or
welding so that it protrudes upward. A positive electrode collector
8 is fixedly connected to the lower end of the positive electrode
2a of the power generating element 2 which protrudes downwards. The
positive electrode collector 8 is made by stamping an aluminum
alloy plate and folded to form slits. The aluminum foils exposed to
the lower ends of the positive electrodes 2a are inserted in and
fixedly connected to the respective slits by clamping or welding.
The one end of the positive electrode collector 8 is extended to
the negative electrode collector 9 along the power generating
element 2 to reach the upper side thereof. A positive electrode
terminal 4 of the aluminum alloy is fixedly connected to the
positive electrode collector 8 by clamping or welding.
[0006] The power generating element 2 to which the positive
electrode collector 8 and the negative electrode collector 9 are
connected is housed within a cell case 3 as shown in FIG. 21. The
cell case 3 is made of an aluminum alloy plate or stainless steel
plate, and is composed of an elliptic-cylindrical vessel-shaped
case body 3a and an elliptic cover plate 3b fit in the upper
opening thereof and sealed by welding on the periphery. The
positive electrode terminal 4 and negative electrode terminal 5
which are fixedly connected to the power generating element 2 are
caused to protrude upwards through the opening holes located at two
positions of the cover plate 2 from the inside of the cell case 3.
These electrode terminals 4 and 5 are electrical insulating sealed
by forming a glass hermetic seal in gaps between themselves and the
opening holes. Incidentally, a metallic ring made of the same
material as the cover plate 3b is electrical insulating secured to
each of these positive electrode terminal 4 and negative electrode
terminal 5 by a glass hermetic seal or ceramic hermetic seal. These
metallic rings are secured to seal the opening holes at two
positions of the cover plate 3b. The cover plate 3b, thereafter, is
fit in the case body 3a and sealed therein by welding.
[0007] The nonaqueous electrolytic secondary cell 1 is accompanied
by the following danger. Namely, when the power generating element
2 is heated excessively while abnormality occurs, the electrolyte
is decomposed to generate gas. Then, the inside pressure is boosted
so that the cell case 3 may be broken. In order to overcome such an
inconvenience, in the conventional art, safety valves 6 were formed
on the bottom of the case body 3a and on the cover plate 3b. The
safety valves 6 are constructed by the plate areas thinned by
forming grooves in the aluminum alloy plate or stainless steel
plate constituting the case body 3a and cover plate 3b. When the
pressure within the cell case 3 is boosted abnormally, the grooved
thin plate areas are broken so that the inside of the cell case is
degassed.
[0008] Now, it should be noted that the gas generated in the
power-generating element 2 can move only toward either the upper
end or lower end along a winding axis direction because the
positive electrode 2a and negative electrode 2b are closely-wound.
In order to avoid such an inconvenience, safety valves 6 are formed
on the bottom of the case body 3a and on the cover plate 3b so that
the gas moved out from the upper and lower ends in the winding axis
direction can be smoothly discharged externally. However, where
such an elliptic-cylindrical nonaqueous electrolytic secondary cell
1 is used as a single cell, when the internal pressure increases,
the planar portion of the side wall of the case body 3a swells
outwardly. Therefore, for example, the gas moved out from the lower
end of the power-generating element 2 can be transferred to the
upper end through the swelled side of the case body 3a. In this
case, the safety valve 6 may be formed on only the cover plate 3b
at the upper end. However, where a plurality of the nonaqueous
electrolytic secondary cells 1 are closely arranged so that they
can be used as a battery, the planar portions of the sides of the
adjacent nonaqueous electrolytic secondary cells push each other so
that each battery cannot swell by the internal pressure unlike the
case of the single cell. Thus, the gas moved out from the lower end
of the power generating element 2 cannot shift. In this case, the
safety valve 6 must be also formed on the bottom of the case body
3a.
[0009] Where the conventional nonaqueous electrolytic secondary
cell 1 is used as a constituent of the battery, it cannot be used
with the bottom of the cell where the safety valve 6 is formed
being closed. For example, in the case of the battery for a special
use such as aeronautics/space, as shown in FIG. 22, a cooling plate
7 of a material having a high thermal conductivity such as an
aluminum alloy is arranged between the plurality of nonaqueous
electrolytic secondary cells 1 and beneath the bottom of each
nonaqueous secondary cell so that the battery can be cooled by a
cooling means (not shown). In this case, the planar portion of the
side of each nonaqueous secondary cell 1 is restrained by the
cooling plate 7 and hence cannot swell. This requires for the
safety valve to be formed on the bottom of the case body 3a.
However, because the bottom of the case body 3a is also blocked by
the cooling plate 7, the safety valve 6 cannot operate
normally.
[0010] Even where the nonaqueous electrolytic secondary cell 1 is
used as a single cell, if the side wall of the case body 3a cannot
swell because the cell is arranged with no gap within an installing
space, the safety valve 6 must be formed on the bottom of the case
body 3a. In this case also, the cell must be used with the bottom
of the cell where the safety valve 6 is formed being not
closed.
[0011] In the case of the cylindrical nonaqueous electrolytic
secondary cell, the entire side wall of the cell case is curved and
has no planar portion. Therefore, even where it is arranged within
an sufficient installing space as a single cell, the side wall of
the cell cannot swell. In this case also, the safety valves must be
formed on the upper and lower face of the cell case, and hence the
cell cannot be used with the bottom of the cell where the safety
valve 6 is formed being closed.
[0012] Such a problem applies to not only the nonaqueous
electrolytic secondary cell, but also all the batteries which
require a safety valve and use a winding type power-generating
element.
SUMMARY OF THE INVENTION
[0013] The present invention has been accomplished in order to
solve such a problem, and it is an object of the present invention
to provide a battery which is provided with a safety valve on the
side wall of a cell case in the vicinity of a bottom thereof so
that the cell can be used with the bottom being closed, and a
battery using such a cell.
[0014] According to the first aspect of the present invention, in a
cell in which a winding type power generating element is housed
within a cell case, on a side wall of the cell case along a winding
axis direction of the power generating element, a safety valve is
formed at a position inclusive of the tip end of a mixture-applied
area of at least one electrode of the power generating element.
[0015] In accordance with the first aspect of the present
invention, since the safety valve is formed at at least one end of
the side wall of the cell case, even where the one end surface of
the battery is closed, the gas moved out from the one end of the
winding type power generating element can be smoothly discharged
externally. The safety valve may be formed at each of both ends of
the side wall of the cell case.
[0016] According to the second aspect of the present invention, in
a battery in which an elliptic-cylindrical winding type power
generating element is housed within an elliptic-cylindrical cell
case, on an elliptic-cylindrical curved surface of a side wall of
the cell case along a winding axis direction of the power
generating element, a safety valve is formed at a position
inclusive of the tip end of a mixture-applied area of at least one
electrode of the power generating element.
[0017] In accordance with the second aspect of the present
invention, since the safety valve is formed at the curved portion
of the elliptic-cylindrical cell case, even where the planar
portion of the side wall is restrained so that it cannot swell, the
inner gas can be smoothly discharged horizontally.
[0018] According to the third aspect of the present invention, in
the battery of the first or second aspect, the height of the cell
along its side wall is 1.5 times or more as large as the narrowest
width of the cell case.
[0019] In accordance with the third aspect of the present
invention, since the length of the power generating element in the
winding direction along the side wall of the cell case is
sufficiently longer than the width thereof, the gas that may not
escape at the one side of the cell case if there is no safety valve
can be surely discharged externally from the safety valve formed on
the side wall.
[0020] According to the fourth aspect of the present invention, in
a battery, a plurality of the cells defined in any of the first to
the third aspect of the present invention are arranged with the tip
end located on their bottom side, and a cooling plate is arranged
on their bottom side and between adjacent cells.
[0021] In accordance with the fourth aspect of the present
invention, even where the side and bottom of the cell case of each
of the batteries are blocked by the cooling plate of the battery,
since the safety valve is formed at the bottom side of the side
wall of each cell case, the gas move out from the bottom of the
winding type power generating element can be smoothly discharged
externally.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In the accompanying drawings:
[0023] FIG. 1 is an overall perspective view of an nonaqueous
electrolytic battery according to an embodiment of the present
invention;
[0024] FIG. 2 is a partially enlarged longitudinal sectional view
showing a structure in the vicinity of the lower end of the
nonaqueous secondary cell;
[0025] FIG. 3 is a longitudinal sectional view showing an internal
structure of the nonaqueous electrolytic secondary cell according
to an embodiment of the present invention;
[0026] FIG. 4 is a perspective view of a battery composed of a
plurality of nonaqueous electrolytic secondary cells according to
an embodiment;
[0027] FIG. 5 is an overall perspective view of a nonaqueous
secondary cell showing a second example of a groove shape of a
safety valve according to an embodiment of the present
invention;
[0028] FIG. 6 is a side view of a nonaqueous secondary cell showing
a second example of a groove shape of a safety valve according to
an embodiment of the present invention;
[0029] FIG. 7 is an overall perspective view of a nonaqueous
secondary cell showing a third example of a groove shape of a
safety valve according to an embodiment of the present
invention;
[0030] FIG. 8 is a side view of a nonaqueous secondary cell showing
a third example of a groove shape of a safety valve according to an
embodiment of the present invention;
[0031] FIG. 9 is an overall perspective view of a nonaqueous
secondary cell showing a fourth example of a groove shape of a
safety valve according to an embodiment of the present
invention;
[0032] FIG. 10 is a side view of a nonaqueous secondary cell
showing a fourth example of a groove shape of a safety valve
according to an embodiment of the present invention;
[0033] FIG. 11 is an overall perspective view of a nonaqueous
secondary cell showing a fifth example of a groove shape of a
safety valve according to an embodiment of the present
invention;
[0034] FIG. 12 is a side view of a nonaqueous secondary cell
showing a fifth example of a groove shape of a safety valve
according to an embodiment of the present invention;
[0035] FIG. 13 is an overall perspective view of a nonaqueous
secondary cell showing a sixth example of a groove shape of a
safety valve according to an embodiment of the present
invention;
[0036] FIG. 14 is a side view of a nonaqueous secondary cell
showing a sixth example of a groove shape of a safety valve
according to an embodiment of the present invention;
[0037] FIG. 15 is an overall perspective view of a nonaqueous
secondary cell showing a seventh example of a groove shape of a
safety valve according to an embodiment of the present
invention;
[0038] FIG. 16 is a side view of a nonaqueous secondary cell
showing a seventh example of a groove shape of a safety valve
according to an embodiment of the present invention;
[0039] FIG. 17 is an overall perspective view of a nonaqueous
secondary cell showing an eighth example of a groove shape of a
safety valve according to an embodiment of the present
invention;
[0040] FIG. 18 is a side view of a nonaqueous secondary cell
showing an eighth example of a groove shape of a safety valve
according to an embodiment of the present invention;
[0041] FIG. 19 is a perspective view showing the structure of a
power generating element according to a conventional art;
[0042] FIG. 20 is a perspective view of a structure of a power
generating element, electrode collectors and terminals;
[0043] FIG. 21 is an overall perspective view of a nonaqueous
electrolytic secondary cell according to another conventional art;
and
[0044] FIG. 22 is a perspective view of nonaqueous electrolyte
secondary cell arranged in parallel according to another
conventional art.
PREFERRED EMBODIMENTS OF THE INVENTION
[0045] Now referring to the drawings, an explanation will be given
of embodiments of the present invention.
[0046] FIGS. 1 to 4 show a first embodiment of the present
invention. Specifically, FIG. 1 is an overall perspective view of
an nonaqueous electrolytic cell. FIG. 2 is a partially enlarged
longitudinal sectional view showing a structure in the vicinity of
the lower end of the nonaqueous secondary cell. FIG. 3 is a
longitudinal sectional view showing an internal structure of the
nonaqueous electrolytic secondary cell. FIG. 4 is a perspective
view of a battery composed of a plurality of nonaqueous
electrolytic secondary cells. In FIGS. 1 to 4, the same reference
numerals refer to the same elements in the conventional arts shown
in FIGS. 19 to 22.
[0047] This embodiment will be explained in connection with a
nonaqueous electrolytic secondary cell 1 provided with a power
generating element 2 which is wound in an elliptic-cylindrical
shape like the conventional arts as shown in FIGS. 19 to 22. As
seen from FIG. 1, a cell case body 3 of the nonaqueous electrolytic
secondary cell 1 is made from an aluminum alloy plate or stainless
plate, and is composed of an elliptic-cylindrical vessel-shaped
case body 3a and an elliptic cover plate 3b fit in the upper
opening thereof and sealed on its periphery by laser welding or TIG
welding. The power generating element 2 as shown in FIGS. 19 to 20
is housed within the cell case 3. The positive electrode terminal 4
and negative electrode terminal 5 which are fixedly connected to
the power generating element 2 are caused to protrude upwards
through the opening holes located at two positions of the cover
plate 3b. These electrode terminals 4 and 5 are dielectrically
sealed by forming a glass hermetic seal. Incidentally, these
positive electrode terminal 4 and negative electrode terminal 5 can
be dielectrically fixedly sealed in the cover plate 3b by means of
a ceramic hermetic seal or screwing a packing material of synthetic
resin as well as the glass hermetic seal.
[0048] The cover plate 3b has a safety valve formed at its central
area like the conventional art. The case body 3a has another safety
valve 6 formed at the lower end of its curved side wall. These
safety valves 6 are constructed by the plate areas thinned by
forming grooves in the aluminum alloy plate or stainless steel
plate constituting the case body 3a and cover plate 3b. These
grooves can be formed by means of cutting, stamping or etching. In
the case of cutting, a machine capable of cutting a curved surface
such as a three-dimensional NC is required. In the case of
stamping, the groove can be formed simultaneously when the case
body 3a is drawn and the cover plate 3b is stamped out. However,
normally, after these machining operations, the groove is formed so
as to print a stamp using a mold having a protrusion along the
groove. In the case of etching, the other surface area of case body
3a and cover plate 3b than the area where the grooves are to be
formed are covered with a protection film. Thereafter, the grooves
are formed by thinning the metallic plate through chemical reaction
of an etching solution. Because of the presence of these safety
valves 6, when the pressure within the cell case 3 is boosted
abnormally, the thin plate groove areas are broken so that the
inside of the cell case is degassed.
[0049] The safety valve 6 to be formed on the side wall of the case
body 3a is formed so that the lower end of the groove is lower than
the lower end position A of the area where the mixture 2d of the
positive electrode 2a and mixture 2e of the negative electrode 2b
are applied in the power generating element 2. As shown in FIG. 3,
since the positive electrode collector 8 for fixing the lower end
of the positive electrode 2a is arranged beneath the power
generating element 2, a gap is formed between itself and the bottom
of the case body 3a. Therefore, the gas moved out from the lower
end of the power generating element 2 can reach the lower end of
the side wall through the above gap. Thus, if the groove of the
safety valve 6 of the case body 3a is formed to reach the lower
level than the lower end of the power generating element 2, even if
the safety valve 6 is not formed on the bottom of the case body 3a,
the gas can be smoothly discharged externally from the lower end of
the side wall of the case body 3a. Further, in the power generating
element 2, the separator 2c and the area of the positive electrode
2a where the mixture 2d is not applied to expose the aluminum foil
and the area of the negative electrode 2b where the mixture 2e is
not applied to expose the copper foil do not have rigidity but some
flexibility. Therefore, the high pressure gas can push away them to
move. Thus, it is not required that the groove of the safety valve
6 of the case body 3a is formed at the lower end of the power
generating element 2. Instead of this, the groove has only to be
formed to reach the lower level than the lower end position A of
the area where the mixture 2d and mixture 2e are applied in the
power generating element 2 as shown in FIG. 2.
[0050] In the nonaqueous electrolytic secondary cell 1 having the
above configuration, even if the side wall of the cell case 3 is
restrained and the bottom of the cell case 3 is blocked, while
abnormality occurs, the gas moved out from the lower end of the
power generating element 2 can be smoothly discharged externally
from the safety valve formed on the side wall of the case body 3a.
Where the length of the power generating element 2 is relatively
short in the direction of winding, the gas generated within the
power generating element 2 can be discharged from the upper end of
the cell case 3a. For this reason, the present invention is
particularly efficient for the nonaqueous electrolytic secondary
cell 1 having a height that is 1.5 time or more as large as the
smaller width of the elliptic cylindrical shape, or the diameter of
the cylindrical shape.
[0051] In this embodiment, as shown in FIG. 4, a plurality of the
nonaqueous electrolytic secondary cells 1 are arranged to
constitute a battery. A cooling plate 7 is closely arranged between
the adjacent nonaqueous electrolytic secondary cells and beneath
the bottoms of these cells. In this case, the planar portion of the
side wall of each of the nonaqueous electrolytic secondary cells 1
is restrained by the cooling plate 7 and cannot swell. Therefore,
when abnormality occurs, it is impossible to shift the gas moved
out from the lower end of the generating element 2 to the outer end
thereof and externally discharge the gas from the safety valve
formed on the cover plate 3b. Since the bottom of the case body 3a
is also blocked by the cooling plate 7, the safety valve 6 cannot
be formed there. However, in the nonaqueous electrolytic secondary
cell 1 according to this embodiment, the safety valve 6 is formed
at the lower end of the curved side wall of the case body 3a so
that the high pressure gas can be externally discharged from the
safety valve 6 through the gap at the bottom of the case body
3a.
[0052] In this embodiment, the safety valve 6 was formed to have a
groove shape of a vertical connection of a "Y" groove and an
inverted, "Y" groove as a first example. However, the groove shape
should not be limited to such a shape in this example as long as it
can be surely broken under prescribed pressure or higher. For
example, the following shapes of the safety valve 6 can be
proposed. In the second example as shown in FIGS. 5 and 6, two
vertical grooves are formed on both sides of the vertical
connection of a "Y" groove and an inverted "Y" groove. In the third
example as shown in FIGS. 7 and 8, the groove shape is formed in a
vertical connection of an upward arrow groove and downward arrow
groove. In the fourth example as shown in FIGS. 9 and 10, two
vertical grooves are formed on both sides of the vertical
connection of an upward arrow groove and a downward arrow groove as
shown in FIGS. 7 and 8. In the fifth example as shown in FIGS. 11
and 12, the groove shape is composed of a groove of a downward
arrow and a horizontal groove connected to the lower end thereof.
In the sixth example as shown in FIGS. 13 and 14, the groove shape
is composed of an upward arrow groove and a horizontal groove
connected to the upper end thereof. In the seventh example as shown
in FIGS. 15 and 16, the groove shape is composed of a square groove
and diagonal line grooves added thereto. In the eighth example as
shown in FIGS. 17 and 18, the groove shape is composed of a single
vertical groove and indentations added to the upper and lower ends
thereof each having a slightly larger diameter than the width of
the vertical groove.
[0053] The safety valve 6, without being formed in the groove shape
as described hitherto, may be also formed by bonding a metallic
plate on an opening hole formed in the case body 3a and cover plate
3b by laser welding so that the opening hole is sealed, or
attaching a pressure valve of an elastic material to the opening
hole.
[0054] In the above embodiment, although the present invention was
applied to the nonaqueous electrolytic secondary cell 1, it may be
applied to any cell as long as it has a winding type power
generating element 2 provided with the safety valve. Further, in
the above embodiment, the present invention was applied to the
elliptic cylindrical type of a cell, it may be applied to a
cylindrical type of a cell. Further, in the above embodiment,
although the safety valve 6 was attached to only the lower end of
the side wall of the cell, it may be attached to the upper end of
the side wall. In this case, the safety valve on the cover plate 3b
is not required. Further, where the upper end surface of the
battery is closed, the safety valve 6 may be provided at only the
upper end of the side wall of the battery.
[0055] In the above embodiment, although the cell case 3 was
composed of the case body 3a and cover plate 3b, it should not be
limited to such a structure, but may have any optional
structure.
[0056] As apparent from the description hitherto made, in the cell
according to the present invention and a battery using such a cell,
the safety valve is formed at the end of the side wall of the cell
case. Therefore, even where the end surface of the cell is blocked,
the gas generated within the cell case can be smoothly discharged
externally.
* * * * *