U.S. patent application number 10/862378 was filed with the patent office on 2004-12-09 for sealed battery and method for manufacturing the same.
This patent application is currently assigned to Matsushita Electric Industrial Co., Ltd.. Invention is credited to Asahina, Takashi, Eto, Toyohiko, Hamada, Shinji, Yuasa, Shinichi.
Application Number | 20040248002 10/862378 |
Document ID | / |
Family ID | 33487583 |
Filed Date | 2004-12-09 |
United States Patent
Application |
20040248002 |
Kind Code |
A1 |
Asahina, Takashi ; et
al. |
December 9, 2004 |
Sealed battery and method for manufacturing the same
Abstract
A sealed battery includes a metal case which functions as a
connection terminal of one polarity and an electrode post which is
mounted to the case in an insulated manner and functions as a
connection terminal of the other polarity. A sealing section with
electrical insulation properties is disposed between the electrode
post formed from a hollow cylinder with one closed end and an
electrode post through-hole provided in the case. A compression
deformation section is produced by deforming the closed end of the
electrode post radially outward, for compressing and sealing the
sealing section, and for securing the electrode post to the
case.
Inventors: |
Asahina, Takashi;
(Toyohashi-shi, JP) ; Hamada, Shinji;
(Toyohashi-shi, JP) ; Eto, Toyohiko; (Toyota-shi,
JP) ; Yuasa, Shinichi; (Kyotanabe-shi, JP) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
Matsushita Electric Industrial Co.,
Ltd.
Osaka
JP
Toyota Jidosha Kabushiki Kaisha
Aichi
JP
|
Family ID: |
33487583 |
Appl. No.: |
10/862378 |
Filed: |
June 8, 2004 |
Current U.S.
Class: |
429/181 ;
29/623.2; 429/161; 429/185 |
Current CPC
Class: |
H01M 50/176 20210101;
H01M 50/545 20210101; Y02E 60/10 20130101; H01M 50/116 20210101;
Y02P 70/50 20151101; H01M 50/119 20210101; Y10T 29/4911 20150115;
H01M 10/36 20130101; H01M 50/172 20210101; H01M 50/578
20210101 |
Class at
Publication: |
429/181 ;
429/185; 429/161; 029/623.2 |
International
Class: |
H01M 002/08; H01M
002/26; H01M 010/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2003 |
JP |
2003-163749 |
Claims
What is claimed is:
1. A sealed battery comprising: a metal case which functions as a
connection terminal of one polarity, an electrode post through-hole
being provided in the case; an electrode plate assembly housed in
the case; an electrode post which is mounted to the case in an
insulated manner and functions as a connection terminal of the
other polarity, the electrode post being formed from a hollow
cylinder with one closed end; a sealing section with electrical
insulation properties, being disposed between the electrode post
and the electrode post through-hole; and a compression deformation
section produced by deforming the closed end of the electrode post
radially outward, for compressing and sealing the sealing section,
and for securing the electrode post.
2. The sealed battery according to claim 1, wherein the compression
deformation section of the electrode post is formed by applying
pressure in an axial direction to the closed end of the electrode
post in a state where a hollow interior of the electrode post is
subjected to fluid pressure.
3. The sealed battery according to claim 1, wherein the electrode
post is brought into contact with a collector that is joined to an
end face of one polarity of the electrode plate assembly, and an
end wall of the compression deformation section of the electrode
post is welded to the collector from a position outside the case,
through a hollow interior of the electrode post.
4. The sealed battery according to claim 3, wherein the end wall of
the compression deformation section and the collector are joined by
any of laser beam welding and electron beam welding.
5. The sealed battery according to claim 1, wherein the sealing
section comprises an O-ring which is sandwiched in a compressed
state between an outside surface of the case and the electrode
post, a backup section that regulates the position of the inner and
outer peripheries of the O-ring, and an insulating spacer which is
disposed between the through-hole and the electrode post, and
between the compression deformation section of the electrode post
and the inside surface of the case.
6. The sealed battery according to claim 1, wherein a collar that
extends radially outwards is provided at the opposite end of the
electrode post, and at least one side edge of the collar runs
parallel to the edge of the prismatic case.
7. The sealed battery according to claim 6, wherein both side edges
of the collar run parallel to the long side surface of the
case.
8. The sealed battery according to claim 6, wherein a protrusion
that corresponds with the electrode post is formed on the opposite
side surface from the side surface of the case of another sealed
battery, the surface on which the electrode post is disposed, and
at least one side edge of the protrusion and one side edge of the
collar are aligned in terms of their relative positions on the
protrusion side surface and the electrode post side surface
respectively.
9. The sealed battery according to claim 6, wherein a connection
plate section that can be elastically displaced in the axial
direction of the electrode post is provided on the collar.
10. A method for manufacturing a sealed battery, comprising:
inserting a hollow cylindrical electrode post with one closed end
into an electrode post through-hole provided in a lid of a case,
with the closed end inserted first and with a sealing section that
displays electrical insulation properties and sealing properties
disposed between the lid and the electrode post; compressing the
sealing section by subjecting the closed end of the electrode post
to an outward expansion in the radial direction and a compression
deformation in the axial direction to seal the sealing section, and
securing the electrode post to the lid; housing an electrode plate
assembly inside the case; joining the lid to the case; joining one
end wall of the electrode post to the end face of one polarity of
the electrode plate assembly through a hollow interior of the
electrode post; and joining the end face of the other polarity of
the electrode plate assembly to the bottom wall of the case.
11. The method for manufacturing a sealed battery according to
claim 10, wherein the compression deformation of the electrode post
is conducted by applying pressure in the axial direction to the
closed end of the electrode post in a state where the hollow
interior is subjected to fluid pressure.
Description
[0001] The present disclosure relates to subject matter contained
in priority Japanese Patent Application No. 2003-163749, filed on
Jun. 9, 2003, the contents of which is herein expressly
incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a sealed battery and a
method for manufacturing the same, and more particularly to an
electrode post structure which enables reductions to be achieved in
the weight of the battery, the number of components, and the
battery cost, while retaining highly reliable sealing of the
electrolyte.
[0004] 2. Description of the Related Art
[0005] In recent years, environmental concerns have prompted
considerable interest in electric vehicles and hybrid vehicles that
use fuel cells or rechargeable batteries as a power source, and the
rechargeable battery that functions as the power source or
auxiliary power source for these vehicles should ideally be as
small and as light as possible, while providing maximum capacity
and output. Examples of sealed rechargeable batteries that satisfy
these requirements include lithium ion rechargeable batteries and
nickel-metal hydride batteries.
[0006] In these types of sealed batteries, if a metal case is used
to reduce gas permeation and improve the cooling properties of the
battery, then the electrode post that functions as the external
connection terminal must be insulated with respect to the case and
sealed with respect to the electrolyte in the region where the post
passes through the case.
[0007] One example of a conventional electrode post construction is
shown in FIG. 8 (see Japanese Patent Laid-Open Publication No. Hei
8-77999). This electrode post 41 is equipped with column sections
43, 44 at the top and bottom of a main body 42, and the lower
column section 44 is inserted into an electrode post through-hole
46 formed in the case 45, with insulating packing 47 provided
between the lower column section 44 and the case 45. A current
collecting washer 49 that is connected to one end of an electrode
plate assembly is provided on the inside surface of the case 45
with packing 48 disposed therebetween, and a crimped section 50
formed on the bottom end of the lower column section 44 connects
the electrode post 41 to the current collecting washer 49 and
secures the electrode post 41 to the case 45.
[0008] Another conventional electrode post construction is shown in
FIG. 9 (see Japanese Patent Laid-Open Publication No. 2000-48803).
This electrode post 51 is inserted into an electrode post
through-hole 56 formed in the case 55, with insulating packing 52
provided between the electrode post 51 and the case 55. Additional
packing 54 is provided between the inside surface of the case 55
and a packing support collar 53, which protrudes outward from the
outer periphery near the bottom of the electrode post 51, and a nut
57 that is screwed onto the externally protruding section of the
electrode post 51 is used to secure the electrode post 51 to the
case 55.
[0009] However, in a battery pack used as the power source for a
vehicle, even a reduction in weight of several hundred grams is
important. Moreover, a battery pack comprises a plurality of cells
connected in series to achieve the prescribed output voltage, and
because the electrode posts are comparatively heavy, the weight of
the electrode posts has a significant effect on the overall weight
of the battery pack. Furthermore, because leakage of the
electrolyte can result in short circuiting caused by corrosion, the
sealing of the electrolyte must be maintained with a high level of
reliability over extended periods, even under severe operating
conditions.
[0010] However, in the electrode post construction shown in FIG. 8,
because only the bottom end of the electrode post 41 is hollow, the
weight of the electrode post is considerable. Furthermore, because
the gap between the main body 42 and the crimped section 50 is
sealed with respect to the electrolyte simply by compressing the
insulating packing 47 between the lower column section 44 and the
through-hole 46, the sealing performance varies considerably, and
achieving reliable electrolyte leakage prevention over an extended
period is difficult.
[0011] Furthermore in the electrode post construction shown in FIG.
9, tightening the nut 57 seals the structure by causing a
compression of both the insulating packing 52 between the electrode
post 51 and the through-hole 56, and the packing 54 between the
packing support collar 53 and the inside surface of the case 55,
and thus provides a superior seal to the construction shown in FIG.
8. However, the sealing pressure generated within the insulating
packing 52 is not particularly high, meaning the sealing
performance cannot be increased significantly, and the increase in
the number of components causes increases in both the weight and
the cost of the structure.
SUMMARY OF THE INVENTION
[0012] The present invention takes the above problems associated
with the conventional technology into consideration, with an object
of providing a sealed battery which achieves reductions in the
weight of the battery, the number of components, and the battery
cost, while retaining highly reliable sealing of the electrolyte,
as well as a method for manufacturing such a sealed battery.
[0013] A sealed battery of the present invention includes a metal
case which functions as a connection terminal of one polarity, and
an electrode post which is mounted to the case in an insulated
manner and functions as a connection terminal of the other
polarity, wherein a sealing section with electrical insulation
properties is disposed between the electrode post, which is formed
from a hollow cylinder with one closed end, and an electrode post
through-hole provided in the case, and a compression deformation
section produced by deforming the closed end of the electrode post
radially outward is used for compressing and sealing the sealing
section, and for securing the electrode post.
[0014] According to such a construction, a hollow cylinder with one
closed end is used for the electrode post, and a compression
deformation section produced by deforming the closed end of the
electrode post is used for compressing and sealing the sealing
section, and for securing the electrode post. Consequently, both
the weight and the cost of the structure are reduced, and highly
reliable sealing is ensured.
[0015] The compression deformation section of the electrode post
can be formed by applying pressure in an axial direction to the
closed end of the electrode post, while the hollow interior of the
electrode post is subjected to fluid pressure.
[0016] Furthermore, by bringing the electrode post into contact
with a collector that is joined to the end face of one polarity of
an electrode plate assembly housed in the case, and then welding
the end wall of the electrode post to the collector from a position
outside the case through the hollow interior of the electrode post,
a direct connection between the electrode post and the electrode
plate assembly is achieved, thereby enabling a reduction in the
connection resistance, as well as reductions in the weight and cost
of the structure.
[0017] The end wall of the electrode post and the collector may be
joined by laser beam welding or electron beam welding.
[0018] Furthermore, the sealing section preferably includes an
O-ring which is sandwiched in a compressed state between the
outside surface of the case and the electrode post, a backup
section that regulates the position of the inner and outer
peripheries of the O-ring, and an insulating spacer which is
disposed between the through-hole and the electrode post, and
between the compression deformation section at one end of the
electrode post and the inside surface of the case. By compressing
the insulating spacer strongly between the corner of the
through-hole and the corner of the deformation section at one end
of the electrode post, and also compressing the O-ring within the
backup section, a double seal is achieved that provides an even
more reliable electrolyte seal.
[0019] Furthermore, a collar that extends radially outwards is
provided at the opposite end of the electrode post from the
deformation section, and at least one side edge of this collar
preferably runs parallel to the edge of the prismatic case. In
those cases where this electrode post is then connected to the
connection terminal of another sealed battery by electron beam
welding or laser beam welding, the connection is achieved by
welding this side edge of the collar, and because the welding is
completed by simply moving the welding point in a straight line, a
high quality weld is formed with good efficiency.
[0020] Furthermore, if both side edges of the collar run parallel
to the long side surface of the case, then both side edges of the
collar can be welded in the same manner, thereby increasing the
surface area of the weld joint, as well as decreasing the
connection resistance between the sealed batteries.
[0021] Furthermore, if a protrusion that corresponds with the
electrode post is formed on the opposite side surface from the side
surface of the case of another sealed battery, on which the
electrode post is disposed, and at least one side edge of the
protrusion and one side edge of the collar are aligned in terms of
their relative positions on the protrusion side surface and the
electrode post side surface respectively, then when a plurality of
sealed batteries are connected in series to form a battery module,
the side edges of the aligned electrode posts and protrusions are
joined by electron beam welding or laser beam welding with good
levels of productivity.
[0022] In addition, if a connection plate section that can be
elastically displaced in the electrode post axial direction is
provided on the collar, then when the electrode posts and
protrusions of a plurality of sealed batteries are joined together
and connected in series to form a battery module, by joining the
side edges of the connection plate sections and the protrusions,
any variations in the dimensions of each sealed battery can be
absorbed by the elastic displacement of the connection plate
section. This means that each sealed battery occupies the same
space, and so when a plurality of battery modules are arranged in
parallel with insulating sheets disposed therebetween to form a
battery pack, the ease of installation of these insulating sheets
is improved.
[0023] A method for manufacturing a sealed battery according to the
present invention includes: inserting a hollow cylindrical
electrode post with one closed end into an electrode post
through-hole provided in a lid of a case, with the closed end
inserted first and with a sealing section that displays electrical
insulation properties and sealing properties disposed between the
lid and the electrode post; activating the sealing properties of
the sealing section and securing the electrode post to the lid by
subjecting the closed end of the electrode post to an outward
expansion in the radial direction and a compression deformation in
the axial direction; housing an electrode plate assembly inside the
case; joining the lid to the case; joining one end wall of the
electrode post to the end face of one polarity of the electrode
plate assembly from a position inside the hollow interior of the
electrode post; and joining the end face of the other polarity of
the electrode plate assembly to the bottom wall of the case.
[0024] The compression deformation of the electrode post can be
conducted by applying pressure in the axial direction to the closed
end of the electrode post, while the hollow interior is subjected
to fluid pressure.
[0025] While novel features of the invention are set forth in the
preceding, the invention, both as to organization and content, can
be further understood and appreciated, along with other objects and
features thereof, from the following detailed description and
examples when taken in conjunction with the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIGS. 1A and 1B show the essential structural elements of a
sealed battery according to a first embodiment of the present
invention, wherein FIG. 1B is a front view, and FIG. 1A is a
cross-sectional view taken along the line IA-IA shown in FIG.
1B;
[0027] FIGS. 2A and 2B show the external appearance of the sealed
battery of the embodiment, wherein FIG. 2A is a perspective view
from the bottom of the case main body, and FIG. 2B is a perspective
view from the lid;
[0028] FIGS. 3A and 3B show an electrode post mounting step
according to the embodiment, wherein FIG. 3A is a cross-sectional
view showing the electrode post inserted through the lid, and FIG.
3B shows a cross-sectional view following formation of a
compression deformation section;
[0029] FIG. 4 is a cross-sectional view showing a connection
between two sealed batteries of the embodiment;
[0030] FIGS. 5A and 5B show an electrode post mounting step for a
sealed battery according to a second embodiment of the invention,
wherein FIG. 5A is a cross-sectional view showing the electrode
post inserted through the lid, and FIG. 5B shows a cross-sectional
view following formation of a compression deformation section;
[0031] FIGS. 6A, 6B, and 6C show the essential structural elements
of a sealed battery according to a third embodiment of the
invention, wherein FIG. 6A is a front view, FIG. 6B is a
cross-sectional view taken along the line VIB-VIB shown in FIG. 6A,
and FIG. 6C is a cross-sectional view taken along the line VIC-VIC
shown in FIG. 6A;
[0032] FIG. 7 is a cross-sectional view showing a connection
between two sealed batteries of the same embodiment;
[0033] FIG. 8 is a cross-sectional view showing the construction of
an electrode post section in a conventional sealed battery; and
[0034] FIG. 9 is a cross-sectional view showing the construction of
an electrode post section in another conventional sealed
battery.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] (First Embodiment)
[0036] A first embodiment of a sealed battery of the present
invention will be described in detail with reference to FIG. 1A
through FIG. 4.
[0037] In FIG. 1A through FIG. 2B, the reference numeral 1
represents a prismatic sealed battery, which includes an electrode
plate assembly 5 and an electrolyte as the power generation
elements housed inside a case 2 formed by welding a metal lid 4 to
the opening at one end of a metal box-shaped case main body 3. In
the case of a nickel-metal hydride rechargeable battery, the case
main body 3 and the lid 4 are formed from nickel-plated steel plate
in order to ensure the required electrolyte resistance, whereas in
the case of a lithium ion rechargeable battery, they are formed
from an aluminum alloy.
[0038] The electrode plate assembly 5 is formed from a plurality of
layered positive and negative electrode plates with separators
disposed therebetween, and the core materials of the positive
electrode plates and the negative electrode plates respectively
protrude from opposite ends of the electrode plate assembly 5,
forming leads 6a, 6b (see FIG. 4) for the positive electrode and
the negative electrode respectively. Collector plates 7a, 7b (see
FIG. 4) for the positive electrode and the negative electrode
respectively are joined to the end faces of the leads 6a, 6b.
[0039] As shown in FIG. 1A and FIG. 2B, a pair of electrode posts
8, which function as the external connection terminals for the
positive electrode for example, are mounted to the lid 4 with an
interval therebetween. Each electrode post 8 is formed from a
hollow cylinder with one closed end, and with a collar 9 that
extends radially outward provided at the other end. Through-holes
10 into which the electrode posts 8 are inserted are formed in the
lid 4, and an annular sealing member 11 with an approximately
U-shaped cross-section is provided at each through-hole 10. The
sealing member 11 contacts both sides of the lid 4 around the
periphery of the through-hole 10, and also engages with the outer
peripheral surface of the electrode post 8 and the inner peripheral
surface of the through-hole 10.
[0040] As shown in FIG. 3A, the sealing member 11 is installed in
the through-hole 10 of the lid 4, and the closed end of the
electrode post 8 is then inserted through the through-hole 10.
Then, as shown in FIG. 3B, the hollow interior of the electrode
post 8 is subjected to fluid pressure as shown by the arrows 100,
while compression is applied from the closed end in the axial
direction shown by the arrow 101, thereby forming a compression
deformation section 12 that extends radially outward at the closed
end of the electrode post 8, as shown in FIG. 3B and FIG. 1A. This
compression deformation section 12 compresses the sealing member 11
causing sealing, and also secures the electrode post 8 to the lid 4
by sandwiching the sealing member 11 and the lid 4 between the
compression deformation section 12 and the collar 9.
[0041] When the lid 4 is then joined to the case main body 3 to
form the case 2, the end wall of the compression deformation
section 12 of the electrode post 8 contacts the collector plate 7a,
and as shown in FIG. 1A, with the structure maintained in this
state, a laser beam 13 or an electron beam is irradiated from
outside the case 2, through the hollow interior of the electrode
post 8 and onto the end wall of the compression deformation section
12, thus welding this end wall to the collector plate 7a, and
joining the collector plate 7a and the electrode post 8 together
via a weld section 14. During this process, because the hollow
interior of the electrode post 8 has a comparatively large
cross-sectional area, a laser beam 13 with a convergence angle of
26 to 300 such as that shown in FIG. 1A can be employed, enabling a
reduction in production costs.
[0042] In addition, as shown in FIG. 2A, a pair of rectangular
protrusions 15 are formed in the bottom wall 3a of the case main
body 3 in positions corresponding with the electrode posts 8, and
the collector plates 7b for the negative electrode contact the
inside surface of the bottom wall 3a of the case main body 3 (see
FIG. 4), and are joined to the bottom wall 3a by a laser beam weld
16 or an electron beam weld on both sides of the corresponding
protrusion 15.
[0043] Furthermore, both side edges of each protrusion 15 are
parallel with the long side surface of the case main body 3, and as
shown in FIG. 1B, the collar 9 of each electrode post 8 is also
formed in a rectangular shape in which both side edges are parallel
to the edges of the long side of the lid 4. Moreover, the side
edges of each protrusion 15 and the side edges of the collar 9 of
the corresponding electrode post 8 are aligned in terms of their
relative positions on the bottom wall 3a and the lid 4
respectively.
[0044] If a plurality of sealed batteries 1 are connected in series
to form a battery module, by joining the electrode posts 8 of one
sealed battery 1 to the protrusions 15 of another sealed battery 1,
then as shown in FIG. 4, the two batteries are joined together with
good productivity by joining the side edges of the collar 9 of each
electrode post 8 to the side edges of the corresponding protrusion
15, by irradiating a laser beam 13 or an electron beam through the
gap between the two battery cases 2 to form a laser beam weld 17 or
an electron beam weld. Because the weld is formed by simply moving
the welding point in a straight line, a high quality weld is formed
with good efficiency, and by welding both side edges of each collar
9 and protrusion 15, the surface area of the weld joint is
increased, and the connection resistance between the sealed
batteries is reduced.
[0045] Next is a description of the steps required for
manufacturing the sealed battery 1 described above. First, as shown
in FIG. 3A, the sealing member 11 is mounted in the electrode post
through-hole 10 provided in the lid 4, and the hollow cylindrical
electrode post 8 with one closed end is inserted into the
through-hole 10, with the closed end inserted first. Subsequently,
as shown in FIG. 3B, the hollow interior of the electrode post 8 is
subjected to fluid pressure, while compression is applied in an
axial direction from the closed end of the electrode post 8, thus
subjecting the closed end to an outward expansion in the radial
direction and a compression in the axial direction, thereby forming
the compression deformation section 12, compressing and sealing the
sealing member 11, and securing the electrode post 8 to the lid
4.
[0046] Next, the electrode plate assembly 5 is housed inside the
case main body 3, and the collector plate 7b and the bottom surface
of the case main body 3 are joined together by either a laser beam
weld 16 or an electron beam weld. Subsequently, the lid 4 is
engaged in the opening of the case main body 3, and the joint
section is sealed by either a laser beam weld 18 or an electron
beam weld, thus sealing the case 2. At this point, the closed end
wall of the electrode post 8 is in contact with the collector plate
7a, and by irradiating a laser beam 13 from outside the case 2,
through the hollow interior of the electrode post 8 and onto this
end wall of the electrode post 8, the electrode post 8 and the
collector plate 7a are connected together via the weld section
14.
[0047] Subsequently, electrolyte is injected into the case 2
through an injection port (not shown in the drawings) formed in
either the bottom wall of the case main body 3 or the lid 4, and a
safety vent (not shown in the drawings) is then installed to close
the injection port and complete the production of the sealed
battery 1.
[0048] According to the embodiment described above, the hollow
cylindrical electrode post 8 with one closed end is used, and the
compression deformation section 12 formed by deforming that closed
end is used to activate the sealing properties of the sealing
member 11 and secure the electrode post 8 to the lid, and
consequently not only are the weight and the cost of the electrode
post reduced, but a highly reliable seal is also achieved.
Furthermore, the compression deformation section 12 is formed in a
single step by subjecting the closed end of the electrode post to
compression in the axial direction, while applying fluid pressure
to the hollow interior of the electrode post 8.
[0049] Furthermore, because one of the collector plates 7a of the
electrode plate assembly 5 housed inside the case 2 contacts the
electrode post 8, and the end wall of the electrode post 8 and the
collector plate 7a are then joined together by either laser beam
welding or electron beam welding conducted by irradiating the beam
from outside the case 2 and through the hollow interior of the
electrode post 8, the electrode post 8 and the electrode plate
assembly 5 are connected directly together with good productivity.
This process also enables a reduction in the number of components,
and reductions in both the connection resistance and the weight of
the structure.
[0050] In addition, because both side edges of the collar 9, which
is provided at the opposite end of the electrode post 8 from the
closed end, run parallel to the long side surface of the case 2,
when the electrode post 8 is connected by laser beam welding or
electron beam welding to a connection terminal such as the
protrusion 15 of another sealed battery 1, the welds are generated
by simply moving the welding point in a straight line along the
side edges of the collar 9, meaning a high quality weld is formed
with good efficiency. Furthermore, by welding both side edges of
the collar 9, the surface area of the weld joint is increased, and
the connection resistance between the sealed batteries is
reduced.
[0051] In particular, because the protrusion 15 that functions as a
connection terminal is formed on the bottom wall 3a of the case
main body 3 in a position corresponding with the electrode post 8,
and the side edges of the protrusion 15 and the side edges of the
collar 9 are aligned in terms of their relative positions, when a
plurality of sealed batteries 1 are connected in series to form a
battery module, the aligned side edges of the electrode post 8 and
the protrusion 15 are joined by either electron beam welding or
laser beam welding with good levels of productivity.
[0052] (Second Embodiment)
[0053] A second embodiment of a sealed battery of the present
invention will be described in detail with reference to FIG. 5A and
FIG. 5B. In the following description of this second embodiment,
those structural features which are the same as the first
embodiment are ignored, with the description focusing on only those
features that are different.
[0054] In the first embodiment, the sealing member 11 with an
approximately U-shaped cross-section is used as the seal for the
electrode post through-hole, but as shown in FIG. 5A and FIG. 5B,
the sealing section 21 in this second embodiment includes an O-ring
22 which is sandwiched in a compressed state between the outside
surface of the lid 4 and the collar 9 of the electrode post 8, a
backup member 23 that regulates the position of the outer periphery
of the O-ring 22, and an insulating spacer 26 made up of a backup
collar 24 that regulates the position of the inner periphery of the
O-ring 22 and a cylindrical spacer 25 that extends in an integrated
manner from the inner periphery of the backup collar 24. The outer
periphery of this cylindrical spacer 25 engages with the inner
periphery of the through-hole 10, whereas the inner periphery of
the spacer 25 engages with the outer periphery of the
pre-deformation electrode post 8, prior to the formation of the
compression deformation section 12, as shown in FIG. 5A. Suitable
materials for these sealing members include polypropylene for the
backup member 23, nylon 66 for the insulating spacer 26, and a high
hardness material for the backup collar 24. The backup collar 24
may also be formed as a separate component from the cylindrical
spacer 25.
[0055] Once the electrode post 8 has been inserted, compression is
applied from the closed end while a fluid pressure load is applied
to the hollow interior of the electrode post 8, in a similar manner
to the first embodiment, thus forming the compression deformation
section 12 at the closed end of the electrode post 8 as shown in
FIG. 5B, as well as compressing the O-ring 22 between the backup
member 23 and the backup collar 24, thus generating a pressure
seal. At the same time, the radial outward expansion of the
compression deformation section 12 forces the cylindrical spacer 25
radially outward, compressing the cylindrical spacer 25 between the
inside surface of the lid 4 and the compression deformation section
12, and a particularly strongly compressed section 27 is generated
between the corner of the through-hole 10 and the corner of the
compression deformation section 12.
[0056] According to the sealing section 21 of this embodiment, the
electrode post through-hole has a double seal provided by the
compressed O-ring 22 and the strongly compressed section 27, and
consequently a highly reliable electrolyte seal is achieved.
[0057] (Third Embodiment)
[0058] A third embodiment of a sealed battery of the present
invention will be described in detail with reference to FIG. 6A
through FIG. 7.
[0059] In this embodiment, a collar 9 of the electrode post 8 is
formed in a substantially circular shape, with integrated wing
pieces 31 extending from both sides of the collar 9 in the
lengthwise direction of the lid 4. By inclining both side sections
(in the width direction of the lid 4) of each wing piece 31 at an
angle .theta. (approximately 4 to 60) so that these side sections
lift up off the lid 4, connection plate sections 32 that can be
elastically displaced in the axial direction of the electrode post
8 are formed at these side sections, as shown in FIG. 6C. Both side
edges of these connection plate sections 32 are positioned parallel
to the long side surface of the case 2, and the distance with which
these side edges are separated from the lid 4, namely the elastic
displacement distance d, is set to approximately 0.2 to 0.3 mm.
Furthermore, the backup member 23 utilizes a rectangular shaped
member that covers the entire area between the wing pieces 31 on
both sides of the collar 9.
[0060] According to this embodiment, because of the connection
plate sections 32 provided on the collar 9 of the electrode post 8,
when the electrode posts 8 and the protrusions 15 of a plurality of
sealed batteries 1 are connected in series to form a battery module
as shown in FIG. 7, the connection plate sections 32 of the
electrode post 8 contact the edges of the protrusion 15. Thereby,
any variations in the dimensions of each sealed battery 1 can be
absorbed by the elastic displacement of the connection plate
sections 32. Accordingly, even if a dimensional variation exists in
one or more of the sealed batteries 1, when the sealed batteries
are combined to form a battery module, each sealed battery 1
occupies the same space. As a result, when a plurality of battery
modules are arranged in parallel with insulating sheets disposed
therebetween to form a battery pack, the ease of installation of
these insulating sheets is significantly improved.
[0061] According to a sealed battery of the present invention and a
method for manufacturing such a sealed battery, a hollow
cylindrical electrode post with one closed end is used, and a
compression deformation section produced by deforming the closed
end of the electrode post is used for compressing and sealing the
sealing section, and for securing the electrode post, and
consequently both the weight and the cost of the structure are
reduced, while a highly reliable seal are achieved.
[0062] Although the present invention has been fully described in
connection with the preferred embodiment thereof, it is to be noted
that various changes and modifications apparent to those skilled in
the art are to be understood as included within the scope of the
present invention as defined by the appended claims unless they
depart therefrom.
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