Title: Sealed prismatic battery connected via openings with conductive connection plates
Abstract: A sealed prismatic battery having a battery case made of a plurality of prismatic cell cases coupled together via partition walls, electrode plate groups, and collectors bonded to lead portions on both sides of the electrode plate groups. In at least one side wall of the battery case is formed openings at locations corresponding to the partition walls such as to open to the cell cases on both sides of the partition walls. Pairs of conductive connection plates are connected to each other through the partition walls and formed with connection pieces that face the openings. The collectors are connected together via the conductive connection plates, i.e., they are connected to the connection pieces after the electrode plate groups are encased in the cell cases, and the openings are sealed by sealing plates in a manner that separates the cell cases.
Patent Number: 6,946,219 Issued on 09/20/2005 to Hamada, et al.
| Inventors:
|
Hamada; Shinji (Toyohashi, JP);
Eto; Toyohiko (Toyota, JP);
Asahina; Takashi (Toyohashi, JP)
|
| Assignee:
|
Matsushita Electric Industrial Co., Ltd. (Osaka, JP);
Toyoda Jidosha Kabushiki Kaisha (Aichi, JP)
|
| Appl. No.:
|
346104 |
| Filed:
|
January 17, 2003 |
Foreign Application Priority Data
| Jan 18, 2002[JP] | 2002-009511 |
| Jul 05, 2002[JP] | 2002-196671 |
| Current U.S. Class: |
429/153; 429/160; 429/161; 429/185 |
| Intern'l Class: |
H01M 006/46 |
| Field of Search: |
429/57,157,158,160,161,185,7,123,99,149,153,176
439/500,504
204/267
320/116,119
|
References Cited [Referenced By]
| Foreign Patent Documents |
| 1087449 | Mar., 2001 | EP.
| |
| 2001/-093503 | Apr., 2001 | JP.
| |
Other References
English Language Abstract of JP Appln. No. 2001-093503.
|
Primary Examiner: Alejandro; Raymond
Attorney, Agent or Firm: Greenblum & Bernstein, P.L.C.
Claims
1. A sealed prismatic battery comprising:
a prismatic battery case comprising a plurality of prismatic cell cases coupled
together via partition walls that extend transverse to side walls of the prismatic
battery case;
a plurality of electrode plate groups respectively encased in the cell cases
and comprising a plurality of positive electrode plates and a plurality of negative
electrode plates alternately stacked upon one another with separators interposed
therebetween, one side edge of the positive electrode plates and the other side
edge of the negative electrode plates protruding in opposite directions to provide
respective lead portions; and
a plurality of collectors each bonded to the lead portions on both sides of the
electrode plate groups, wherein
a plurality of openings are provided at least in one side wall of the prismatic
battery case at locations corresponding to the partition walls so as to extend
across two adjacent cell cases on both sides of each partition wall,
pairs of conductive connection plates are arranged on both sides of each of the
partition walls so as to be connected together through the partition walls, part
of the conductive connection plates facing the openings,
the collectors are connected to the part of the conductive connection plates
facing the openings after the electrode plate groups are accommodated in the cell
cases, and
the openings are sealed in a manner that separates the cell cases.
2. The sealed prismatic battery according to claim 1, further including a communicating
hole provided in each of the partition walls, wherein the conductive connection
plates are provided with protrusions that fit into the communicating hole, the
protrusions being connected together through the communicating hole, and wherein
a sealing material is provided between a peripheral portion of the communicating
hole in the partition walls and the conductive connection plates at least on one
side of the partition walls.
3. The sealed prismatic battery according to claim 2, wherein said sealing material
is an O-ring fitted in a sealing groove provided at a peripheral portion of the
communicating hole in the partition wall.
4. The sealed prismatic battery according to claim 3, wherein sealant is provided
between the O-ring and the conductive connection plate.
5. The sealed prismatic battery according to claim 2, wherein the protrusions
of the conductive connection plates are connected by resistance welding.
6. The sealed prismatic battery according to claim 1, further including a communicating
hole provided in each of the partition walls, wherein the conductive connection
plates on one side of the partition walls are provided with protruding shafts that
extend through the communicating hole and contact the conductive connection plates
on the other side of the partition walls, and wherein an O-ring is provided between
outer periphery of the protruding shafts and inner periphery of the communicating hole.
7. The sealed prismatic battery according to claim 6, further including a fixing
member for fixing the conductive connection plates on one side of the partition
walls to the partition walls.
8. The sealed prismatic battery according to claim 1, wherein the conductive
connection plates and the collectors are connected by resistance welding.
9. The sealed prismatic battery according to claim 1, wherein the conductive
connection plates and the collectors are connected by laser beam welding.
10. The sealed prismatic battery according to claim 1, further including a pair
of connection terminals and connection holes provided in both end faces of the
prismatic battery case and in an upper part of each of the partition walls, wherein
the collectors of adjacent cell cases are connected together through the connection
holes, and the collectors in the cell cases at both ends of the prismatic battery
case are connected to the pair of connection terminals, respectively.
11. A sealed prismatic battery comprising:
a prismatic battery case comprising a plurality of prismatic cell cases coupled
together via partition walls that extend transversely to side walls of the prismatic
battery case;
a plurality of electrode plate groups, side edges of the electrode plates protruding
from the cell cases to form lead portions;
a plurality of collectors each secured to a lead portion;
a plurality of openings in at least one side wall of the prismatic battery case
positioned at locations corresponding to the partition walls so as to extend across
two adjacent cell cases on each side of a partition wall;
pairs of conductive connection plates provided on both sides of each of the partition
walls so as to be connected through the partition walls, a part of the conductive
connection plates facing the openings;
the collectors being connected to a part of the conductive connection plates
that face the openings; and
a sealing plate that seals the opening so that the cell cases are separate.
Description
The present disclosure relates to subject matter contained in priority Japanese
Patent Application Nos. 2002-9511 and 2002-196671, filed on Jan. 18, 2002 and Jul.
5, 2002, respectively, the contents of which is herein expressly incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a sealed prismatic battery, and particularly
to a prismatic battery module consisting of a plurality of cells with lower internal resistance.
2. Description of Related Art
One known rechargeable battery module consisting of a plurality of cells to achieve
required power capacity has the following structure: The plurality of prismatic
cells are arranged in parallel, with their longer lateral walls in contact with
each other, and united by restraining bands together with end plates placed on
the outer sides of the cells at the either end. Leads extending from the top ends
of electrode plates of the cells upwards are connected to terminals mounted in
the lid of the battery case, and these terminals of the cells are connected to
each other via connection plates.
The cells are connected via a long connection path with many connection parts
in this battery, resulting in large components' resistance. In fact, the proportion
of the components' resistance in such a battery to reaction resistance caused by
the reaction between positive and negative electrode plates and liquid electrolyte
in the battery was as high as 40 to 50%, and the high heat generation because of
the large internal resistance was a major barrier to the realization of higher
power output or improvement in battery life. There was also the problem of high
costs because of the large number of components required for the complex connection
structure of the cells.
In view of this, the applicants of the present invention have proposed a sealed
prismatic battery 101 containing a plurality of cells 102 shown in
FIG. 6 and FIG. 7. The battery 101 has a flat prismatic battery
case 103 made of prismatic cell cases 104, which have short lateral
walls and long lateral walls, of serially arranged cells 102. These cells
are connected together in such a manner that their short lateral walls are used
as partition walls 105 between the cells. The open top ends of the cell
cases 104 are closed by an integral lid 106. Connection holes 107
are formed in the short lateral walls of the cell cases 104 at the far ends
and in an upper part of each partition wall 105. Each cell case 104
constitutes a cell 102, accommodating liquid electrolyte and an electrode
plate group 108 consisting of stacked-up rectangular positive and negative
electrode plates and separators interposed in between them. Lateral edges on one
side of the alternately stacked-up positive and negative electrode plates are protruded
in opposite directions to form positive and negative leads 109
a,
109
b, respectively, to which collector plates 110
a,
110
b are connected by welding or the like.
In an upper part of the collector plates 110
a, 110
b is
protruded a connection boss 111 which fits into the connection hole 107.
The connection bosses 111 of positive and negative collector plates 110
a,
110
b are connected together by welding between adjacent cell cases
104. In the connection holes 107 in the end faces of the cell cases
104 at either far end are fitted positive and negative connection terminals
112 with connection bosses 113, respectively, and these connection
bosses 113 are each connected to the connection bosses 111 of positive
and negative collector plates 110
a, 110
b by welding.
The plurality of cells 102 are thus connected in series in the battery case
103 such as to output power via the connection terminals 112 at both ends.
In this structure, however, while the current path from the positive and negative
electrode plates to their respective leads 109
a, 109
b and
collector plates 110
a, 110
b is short, the connection
path between adjacent collector plates 110
a, 110
b is
long as indicated by the arrows in FIG. 8, since they are connected via one welded
portion at the tips of their respective connection bosses 111 at the top.
Also, because they are connected at one location, the internal resistance is high.
Furthermore, because of this detouring connection path, the current distribution
in the electrode plate group 108 is uneven as indicated by white arrows,
i.e., more current flows at portions nearer to the connected part of the collector
plates 110
a, 110
b. As a result, power generation of
the electrode plate group 108 is not uniform, leading to power loss.
SUMMARY OF THE INVENTION
The present invention has been devised in light of the problems in prior art
described above, its object being to provide a sealed prismatic battery having
lower internal resistance per cell and being capable of outputting higher power
by ensuring that power generation of all the electrode plate groups is uniform.
A sealed prismatic battery according to the present invention includes:
a prismatic battery case made of a plurality of prismatic cell cases coupled
together
via partition walls;
a plurality of electrode plate groups respectively encased in the cell cases
and
comprised of a plurality of positive electrode plates and a plurality of negative
electrode plates alternately stacked upon one another with separators interposed
therebetween, one side edge of the positive electrode plates and the other side
edge of the negative electrode plates being protruded in opposite directions to
form respective lead portions; and
a plurality of collectors each bonded to the lead portions on both sides of the
electrode plate groups, wherein
a plurality of openings are formed at least in one side wall of the prismatic
battery
case at locations corresponding to the partition walls such as to bridge across
two adjacent cell cases on both sides of each partition wall,
pairs of conductive connection plates are arranged on both sides of each of
the partition walls such as to be connected together through the partition walls,
part of the conductive connection plates facing the openings,
the collectors are connected to the part of the conductive connection plates
facing the openings after the electrode plate groups are accommodated in the cell
cases, and
the openings are sealed in a manner that separates the cell cases.
With this structure, collectors of adjacent cells facing each other via the
partition walls are connected together at a location in the side wall of the prismatic
battery case via the pair of conductive connection plates that extend through the
partition walls. Consequently, collectors can be connected together at a desired
location, and the connection path is made shorter, whereby the connection resistance
between adjacent cells is reduced. Also, the current distribution between adjacent
cells is made even, which further reduces the internal resistance per cell and
makes power generation of the electrode plate groups uniform, leading to higher
power output. The connection between the conductive connection plates and collectors
is readily achieved by connecting them at the openings formed in the side wall.
The openings are tightly sealed after establishing the connection, so that no liquid
leakage occurs.
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
FIG. 1A is a longitudinal sectional side view taken in the direction of arrows
IA—IA of FIG. 1B, illustrating a sealed prismatic battery according to one
embodiment of the present invention, and FIG. 1B is a longitudinal sectional front
view taken in the direction of arrows IB—IB of FIG. 1A;
FIG. 2 is an enlarged cross-sectional top plan view taken in the direction of
arrows II—II of FIG. 1B;
FIG. 3 is an enlarged cross-sectional top plan view of major parts in which
a sealing plate is melt-bonded;
FIG. 4A is a front view of major parts taken in the direction of arrows IVA—IVA
of FIG. 1A, and FIG. 4B is a front view of a sealing plate;
FIG. 5A to FIG. 5C illustrate a sealed prismatic battery according to another
embodiment of the present invention, FIG. 5A being an enlarged cross-sectional
top plan view of major parts, FIG. 5B being a cross section taken in the direction
of arrows VB—VB of FIG. 5A, and FIG. 5C being a cross section taken in the
direction of arrows VC—VC of FIG. 5B;
FIG. 6 is a partial longitudinal cross-sectional front view of a conventional
sealed prismatic battery;
FIG. 7 is a partly broken perspective view of the battery case of the conventional
battery; and
FIG. 8 is a diagram for showing the current paths in the conventional battery.
DESCRIPTION OF PREFERRED EMBODIMENTS
One embodiment of a sealed prismatic battery according to the present invention
will be hereinafter described with reference to FIG. 1A to FIG.
4B.
The sealed prismatic battery
1 of the present invention has a prismatic
battery case
3 made of a plurality of prismatic cell cases
4, which
have short lateral walls and long lateral walls and are connected together in such
a manner that their short lateral walls are used as partition walls
5. The
battery case
3 is made of synthetic resin such as a PP/PPE alloy which is
repellent against liquid electrolyte. In the partition walls
5, connection
holes
7 are formed in an upper part, and in addition, a pair of communicating
holes
16 are formed at a suitable interval at upper and lower positions
lower than the middle part. On one face of the partition walls
5 around
these communicating holes
16 are formed sealing grooves
17.
In one side wall
20 of the battery case
3 is formed a pair of openings
18 at locations corresponding to the partition walls
5 such as to
open to the cell cases
4 on both sides of the partition walls. These openings
18 are arranged at the same height as the pair of upper and lower communicating
holes
16. They have a width so as to allow edge portions
30 that
are bent of collectors
10 on both sides of the partition wall
5 to
expose to a sufficient extent, and a height that is suitably set. In the illustrated
example, a coupling piece
19 is provided across the openings
18 in
a vertically central location for the purpose of reinforcement, and so both openings
18 are divided into upper and lower openings
18a,
18b, respectively.
On both sides of the partition wall
5 surrounding the communicating holes
16 are provided conductive connection plates
21, which are made of
steel plate that is nickel-plated so as to be repellent against the liquid electrolyte.
Each conductive connection plate
21 is formed of an upper connection plate
22a and a lower connection plate
22b that are coupled
by a bridge portion
21a in the middle. In both connection plates
22a,
22b are formed connection bosses
23 that
fit into the upper and lower communicating holes
16, respectively. These
connection bosses
23 are abutted from both sides of each partition wall
5 and connected together via welds
24 formed by resistance welding.
One side edge of each connection plate
22a,
22b on
the side of one side wall of the battery case
3 where the openings
18
are formed is protruded towards the openings
18a,
18b,
respectively, and bent in L-shape so as to form connection pieces
25 that
face the openings
18a,
18b.
O-rings
26 are fitted in the sealing grooves
17 when the conductive
connection plates
21 are placed on both sides of the partition walls
5,
so that the O-rings
26 are compressed between the sealing grooves
17
and the conductive connection plates
21 to generate a sealing surface pressure.
In addition, sealant
27 such as pitch is applied to the interface between
the O-rings
26 and the conductive connection plates
21.
It would be preferable both in terms of processing efficiency and sealing performance
to fill the sealing grooves
17 with pitch or the like and set the O-rings
26 therein, so that the O-rings
26 are temporarily retained there.
The conductive connection plates
21 are then inserted into the cell cases
4 on both sides of each partition wall
5, and their connection bosses
23,
23 welded together.
After setting the conductive connection plates
21 on both sides of the
partition walls
5 between the cell cases
4, electrode plate groups
8, to both sides of which collectors
10 have been bonded, are inserted
into the cell cases
4 together with liquid electrolyte, whereby discrete
cells
2 are constituted. In an upper part of the partition walls
5
of the battery case
3 are formed connection holes
7, so that the
collectors
10,
10 of adjacent cells
2,
2 are connected
via their connection bosses
11 that fit into the connection holes
7.
The electrode plate group
8 is made up of a plurality of positive and
negative electrode plates that are stacked up alternately. Each positive electrode
plate is enveloped in a bag-shaped separator having an opening on one side, so
the separator is interposed between each pair of positive and negative electrode
plates. One side edge of positive electrode plates and the other side edge of negative
electrode plates are protruded in opposite directions so as to form respective
lead portions
9. The positive electrode plates are made of a nickel foam
metal coated with nickel hydroxide except for the lead portion
9. A portion
of the nickel foam metal that is to become the lead portion
9 is compressed,
and a lead plate is seam welded by ultrasonic welding to one face of this portion.
The negative electrode plates are made of a nickel punched metal coated with negative
electrode constituent materials including hydrogen-absorption alloy except for
the lead portion
9.
Collectors
10 are made of nickel-plated steel plate and bonded
to the lead portions
9 on both sides of the electrode plate group
8.
The bond between the collectors
10 and lead portions
9 is achieved
by electron beam welding or the like at a plurality of bonds
28 at vertically
spaced points in the collectors
10, as shown in FIG.
1A and FIG.
1B.
When the electrode plate group
8 is accommodated in each cell case
4,
part of the lateral edge bent portions
30 of collectors
10 which
faces the openings
18 (
18a,
18b) is in contact
with the inner face of the connection pieces
25 of the conductive connection
plates
21, and electrical connection therebetween is ensured by a weld
29
formed by resistance welding. Welding of the lateral edge bent portions
30
of collectors and the connection pieces
25 is carried out as follows: A
pair of welding electrodes are abutted to the connection pieces
25,
25
of the upper and lower connection plates
22a,
22b and
welding current is applied, which flows from the upper connection plate
22a
into the lower connection plate
22b via the collector
10.
Since the bridge portion
21a has a small cross section, short-circuiting
current is negligible and the welding is achieved reliably. It is preferable in
terms of welding that the connection plates
22a,
22b are
completely separate, but the provision of the bridge portion
21a facilitates
the handling of the conductive connection plates
21.
After connecting the connection pieces
25 of the conductive connection
plates
21 and the lateral edge bent portions
30 of the collectors
10 by welding, sealing plates
31 shown in FIG. 4B are fitted to cover
the openings
18 as illustrated in imaginary lines in FIG.
2 and FIG.
4A and melt-bonded as shown in FIG. 3, so that the openings
18 are
sealed in a manner that separates the cell cases
4,
4 on both sides
of the partition wall
5. The sealing plate
31 is provided with sealing
basses
32 as shown in FIG. 4B at its periphery and at portions that will
abut the end face of the partition wall
5 so as to ensure the seal. When
melt-bonded, it becomes one piece with the side wall
20 of the battery case
3 as shown in FIG.
3.
According to this embodiment, collectors
10,
10 of adjacent
cells
2,
2 facing each other via the partition walls
5 are
connected at a location in the side wall
20 of the battery case
3
via the conductive connection plates
21 that extend through the partition
walls
5. Collectors
10,
10 can thus be connected together
at a desired location. Therefore, the connection path is shorter than the prior
art example with a detouring current path around the top ends of the collectors
10, and the connection resistance between adjacent cells
2,
2
is accordingly reduced. Also, the current distribution between adjacent cells
2,
2 is made even, which further reduces the internal resistance per cell
2
and leads to higher power output.
The connection between the conductive connection plates
21 and collectors
10 is readily achieved by connecting the connection pieces
25 of
the conductive connection plates
21 and the lateral edge bent portions
30
of the collectors
10 at the openings
18 formed in the side wall
20.
The openings
18 are tightly sealed by the sealing plate
31 after
establishing the connection, so that no liquid leakage occurs from or between the
cells
2.
The conductive connection plates
21 disposed on both sides of the partition
walls
5 are formed with connection bosses
23 that fit into the communicating
holes
16 formed in the partition walls
5, and these connection bosses
23,
23 are connected together. Therefore, the basic structure of
the prior art battery case
3 can be used with only additional communicating
holes
16 formed as required. Sealing is achieved by the O-rings
26
interposed between the conductive connection plates
21 and the periphery
of the communicating holes
16 in the partition walls
5, so liquid
leakage through the communicating holes
16 is prevented. The sealant
27
provided in addition to the O-rings
26 fitted in the sealing grooves
17
ensures highly reliable sealing performance.
The connection between the connection bosses
23,
23 of the conductive
connection plates
21, or between the connection pieces
25 of the
conductive connection plates
21 and the lateral edge bent portions
30
of the collectors
10, can be achieved by various means such as laser beam
welding, electron beam welding, resistance welding, or a conductive bond. Resistance
welding is most preferable for the connection of the connection bosses
23,
23, since the welds
24 ensure reliable connection with lower resistance,
which is advantageous for the realization of a high power output battery with low
internal resistance.
In this embodiment, moreover, the collectors
10,
10 of adjacent
cells
2,
2 are connected together via the connection holes
7
formed in the upper part of the partition walls
5, and likewise, the connection
terminals
12 at either end of the battery case
3 are connected to
the collectors
10 via the connection holes
7 formed in the end faces
of the battery case
3. Therefore, the production equipment for the prior
art sealed prismatic batteries in which collectors
10,
10 are connected
together in an upper part can be utilized, with only the additional feature described
above being applied to reduce the connection resistance. Having the connection
terminals
12 for the connection with external terminals in the upper part
of both end walls of the battery case
3 offers advantages of ease of connection
with other sealed prismatic batteries
1 and ease of securing insulation
when providing a water cooling mechanism or the like.
Next, another embodiment of the sealed prismatic battery according to the present
invention will be described with reference to FIG. 5A to FIG.
5C. The basic
structure is the same as the embodiment described in the foregoing, so the description
will be made only with regard to the differences.
In this embodiment, one communicating hole
43 is formed in each of the
partition walls
5, and pairs of conductive connection plates
41,
42 are placed on both sides of each of the partition walls
5. On
one conductive connection plate
41 is formed a protruding shaft
44
which extends through the communicating hole
43 and touches the other connection
plate
42. The tip of the protruding shaft
44 is connected to the
conductive connection plate
42 via a weld
46 by resistance welding.
An O-ring
45 is fitted in between the inner periphery of the communicating
hole
43 and the outer periphery of the protruding shaft
44 in a compressed
state to provide a predetermined sealing surface pressure.
One side edge of each of the conductive connection plates
41,
42
on the side of one side wall
20 of the battery case
3 where the openings
18 are formed is protruded towards the openings
18, and bent in L-shape
so as to form a connection piece
47 that faces the openings
18. To
the inner face of these connection pieces
47 are contacted part of the lateral
edge bent portions
30 of collectors
10 of the electrode groups
8
facing the openings
18, and connected thereto via welds
48. The welds
48 can be formed by any of resistance welding, laser welding, or electron
beam welding. Resistance welding can be carried out as follows: cut-outs
49
are formed at a vertically central location of the conductive connection plates
41,
42 from the connection pieces
47 into the central portion
as indicated by imaginary lines in FIG. 5C. A pair of welding electrodes are abutted
to the connection pieces
47 above and below the cut-outs
49, and
welding current is applied. The connection pieces
47 and the lateral edge
bent portions
30 are thereby connected together via the welds
48.
Laser beam welding can also advantageously be applied in terms of workability,
since, in that case there is no need of providing cut-outs
49 or of applying
pressure which is necessary for the resistance welding.
On one face of the partition walls
5 on the side on which the conductive
connection plates
41 are arranged are protruded positioning bosses
50a,
50b above and below the communicating hole
43 at suitable
intervals. Correspondingly, the conductive connection plates
41 are formed
with positioning holes
51a,
51b with a slightly larger
diameter than that of the positioning bosses
50a,
50b.
Further, the positioning hole
51b is elongated to accommodate variations
resulting from dimensional tolerances. The positioning bosses
50a,
50b extend through the positioning holes
51a,
51b
and protrude therefrom.
Thus, with the protruding shaft
44 being inserted into the communicating
hole
43 and the O-ring
45 fitted between them, whereby the shaft
is automatically adjusted to be coaxial with the hole, and with the positioning
bosses
50a,
50b fitted in respective positioning holes
51a,
51b, the protruding parts of the positioning bosses
50a,
50b are hot-melted using heated plates, so as
to fix the conductive connection plate
41 to the partition wall
5.
These positioning bosses
50a,
50b and positioning holes
51a,
51b constitute a fixing member
52 for positioning
and fixing the conductive connection plate
41 to the partition wall
5.
This fixing member
52 may be provided also to the conductive connection
plate
42 for ease of providing the welds
46.
According to this embodiment, leakage prevention of the communicating hole
43 in the partition wall
5 is achieved by the O-ring
45 interposed
between the inner periphery of the communicating hole
43 and the outer periphery
of the protruding shaft
44 in a compressed state. The compression rate of
O-rings
45 is thereby made precise and stable, and therefore reliable sealing
performance is ensured. Also, with this structure, welding of the protruding shaft
44 of the conductive connection plate
41 to the conductive connection
plate
42 can readily and reliably be performed without being affected by
a reaction force from the compressed o-rings
45. The resultant connection
is therefore reliable and has low resistance.
The conductive connection plate
41 is fixed to the partition wall
5
as being precisely positioned by means of the fixing member
52 consisting
of the positioning bosses
50a,
50b and positioning
holes
51a,
51b. Therefore, the conductive connection
plates
41,
42, after being fixed in position, will not easily be
moved by some external force, which means there will be no variations in the compressed
state of O-rings
45 and their high sealing performance is maintained.
In the embodiments described above, openings
18 are formed in one side
wall
20 of the battery case
3 at locations corresponding to the partition
walls
5, and the connection pieces
25,
47 extending from one
side of the conductive connection plates
21,
41,
42 are connected
to the lateral edge bent portions
30 on one side of the collectors
10.
Alternatively, the openings
18 may be formed in both side walls at locations
corresponding to the partition walls
5 in a zigzag arrangement. Another
option is to form the openings
18 in both side walls
20 of the battery
case
3 such as to face each other, so that the collectors
10,
10
are connected to the connection pieces
25,
47 of the conductive connection
plates
21,
41,
42 on both sides. Connecting the collectors
10,
10 together on their both Bides is advantageous because it leads
to even lower connection resistance, and prevents adverse effects of one-sided
load applied to the electrode plate groups
8 when performing the welding
and any displacement caused by the load.
According to the sealed prismatic battery of the present invention, collectors
of adjacent cells facing each other via the partition walls are connected together
at a location in the side wall of the battery case via the conductive connection
plates that extend through the partition walls. Therefore, collectors can be connected
together at a desired location, and the connection path is made shorter than the
case in which collectors are connected at their top ends via a detouring current
path, whereby the connection resistance between adjacent cells is reduced. Also,
the current distribution between adjacent cells is made even, which further reduces
the internal resistance per cell, and makes power generation of the electrode plate
groups uniform, leading to higher power output.
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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