Chemistry: electrical current producing apparatus – product – and – Current producing cell – elements – subcombinations and... – Cell enclosure structure – e.g. – housing – casing – container,...
Reexamination Certificate
1999-06-15
2001-11-06
Brouillette, Gabrielle (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Current producing cell, elements, subcombinations and...
Cell enclosure structure, e.g., housing, casing, container,...
C429S175000, C429S148000, C429S120000, C429S057000, C429S158000
Reexamination Certificate
active
06312851
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a sealed secondary battery assembly employed for nickel-hydrogen secondary batteries or the like constituting the drive power source for an electric vehicle.
BACKGROUND ART
Sealed secondary battery assemblies of this type are previously known and are disclosed in Laid-Open Japanese Patent Publication No.7-85847. This prior art example has a construction as shown in FIG.
16
. Specifically, electricity generating elements are accommodated in battery cases
36
formed in rectangular tubular shape having a bottom, the apertures of these battery cases
36
are sealed by covers
37
to constitute cells
32
, a plurality of which are arranged in series, the battery cases
36
of these cells
32
being connected in tightly restrained condition by means of end plates
35
and restraining straps
34
. Also, pillar-shaped positive electrode terminals
38
and negative electrode terminals
39
of the cells
32
penetrate through covers
37
and project above them, these terminals
38
and
39
being electrically connected by means of an electrical connection bar
40
.
However, with a construction as in the prior art example wherein battery cases
36
are tied together and held in restrained fashion by means of end plates
35
and restraining straps
34
, when the cells
32
expand as for example during charging, a condition as shown in
FIG. 17
is produced, with stress being concentrated at the portions indicated by P.
This stress concentration gives rise to creep deformation and as a result the durability of battery cases
36
in regard to vibration or shock is severely impaired.
Also, in the case of a construction as in the prior art example in which the positive electrode and negative electrode terminals
38
and
39
project above cover
37
and are electrically connected by an electrical connection bar
40
, the secondary battery is increased in height by the amount to which the positive electrode and negative electrode terminals
38
and
39
project above cover
37
; this is contrary to demands for increased compactness. Also, there was the problem that sealing had to be carried out individually between positive electrode and negative electrode terminals
38
,
39
and cover
37
and if sealing was insufficient internal liquid or gas could leak directly to the outside.
Also, with a construction as in the prior art example wherein the electrical connection between the individual cells is effected on the outside, the positive electrode and negative electrode terminals
38
and
39
must be given a sealing function, electrical connection function, and function of effecting connection between themselves and the electricity-generating elements within the batteries. The construction of the positive electrode and negative electrode terminals
38
and
39
therefore becomes complicated and costly, and, as a result, the total cost of the sealed secondary battery assembly becomes high.
In the light of the above demands for compactness and demands for ensuring sealing strength and lowering costs, the inventors of the present invention conceived, as a way of solving the problems of the prior art example, an internally connected construction wherein electrical connection between the terminals is made within the batteries. In this internally connected construction, as shown in
FIG. 19
, electrical connection between two cells
32
,
32
is made using an electrical connecting rod
41
that passes through the connecting walls
45
,
45
of adjacent battery cases
36
. Then, at the location Q where electrical connecting rod
41
passes through, the three items: electrical connecting rod
41
and the two connecting walls
45
,
45
are integrally coupled by a resin welding technique.
However, if the internally connected construction shown in
FIG. 18
is adopted, when cells
32
expand during charging etc., the condition shown in
FIG. 17
is produced, with stress being concentrated in the portions shown by Q in FIG.
18
. Such stress concentration produces creep deformation and this gives rise to the problem that the durability of battery cases
36
and electrical connecting rods
41
in regard to vibration and impact is severely impaired.
An object of the present invention is to solve the above problems and to provide a sealed secondary battery assembly of excellent cooling construction.
DISCLOSURE OF THE INVENTION
In order to achieve the above objects, the present invention provides a sealed secondary battery assembly in which electricity-generating elements are accommodated in battery cases formed in rectangular tubular shape having a bottom, and a plurality of cells constituted by sealing the apertures of these battery cases by covers are arranged in series, these cells being electrically connected by means of electrical connection elements, characterized in that the battery cases of the individual cells are constituted by a unitary battery case and the electrical connection elements are arranged so as to pass through partition sections that define the space for the individual cells, and coolant passages that communicate with the outside are formed in the partition sections.
With the above construction, since the battery cases of the individual cells are constituted by a unitary battery case, even if the individual cells expand during charging etc., the stress that is generated under these circumstances is not concentrated in a specific location (P of
FIG. 17 and Q
of
FIG. 18
) but is dispersed to the entire partition section that defines the space of the individual cells. A sealed secondary battery assembly of excellent durability in regard to vibration or impact can therefore be provided.
Also, with the above construction, the sealing structure becomes simple, since an internally connected structure i.e. a structure whereby the electrical connection elements are arranged so as to pass through the partition section is adopted. Also compactness of the secondary battery can be achieved.
Furthermore, with the above construction, since coolant passages that communicate with the outside are formed in the partition sections, effective cooling of the secondary battery can be achieved by forcibly passing cooling air for example to these coolant passages.
If a construction is adopted whereby the battery cases of the individual cells are separately manufactured and a unitary battery case is constituted by joining up these battery cases, and irregularities are provided on the connection face of each battery case in order to form coolant passages, the following benefits are obtained. Since manufacture of the individual battery cases is easy and the width of the coolant passages (gap in the direction of connection of the cells) can be made narrower than with a unitary battery case consisting of a unitary molding, to be described, the dimension of the sealed secondary battery assembly in the cell connection direction can be made shorter i.e. it can be made more compact. Specifically, owing to the difficulty of the molding technique, a unitary battery case consisting of a unitary molding can only be formed with coolant passages of minimum width about 5 mm; making this width any smaller is very difficult in terms of mass production. However, if a construction is adopted in which the coolant passages are formed on joining up the battery cases by providing irregularities for formation of coolant passages in the connecting faces of the individual battery cases, this width can be reduced down to about 2 mm, so increased compactness of the sealed secondary battery assembly can be achieved.
If a construction is adopted such that a projection is provided on the connecting faces of each battery case and the coolant passages are formed by bringing these projections into abutment on connection, standardization of the individual battery cases is facilitated.
According to the above invention, if the battery cases are made of resin and these battery cases are joined up by welding or adhesion, a large molding machine or the like for molding a unitary battery case is u
Fukuda Shinsuke
Iwamura Akira
Sato Kenji
Takaki Mitsugu
Yokoyama Toshinobu
Alejandro R.
Brouillette Gabrielle
Jordan and Hamburg LLP
Matsushita Electric - Industrial Co., Ltd.
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