Chemistry: electrical current producing apparatus – product – and – Plural concentric or single coiled electrode
Reexamination Certificate
2001-11-21
2004-06-08
Kalafut, Stephen J. (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
Plural concentric or single coiled electrode
C429S211000, C029S623100
Reexamination Certificate
active
06746796
ABSTRACT:
The present application claims priority of Japanese Patent Application No. 2000-358566 filed on Nov. 24, 2000, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrode-rolled battery, and more particularly relates to an electrode-rolled battery and a method of manufacturing the electrode-rolled battery suitable to supply a large current to a load such as a battery section in an electric car.
2. Description of Related Art
As to an electrode-rolled battery such as a lithium-ion secondary battery, a band-shaped anode and a band-shaped cathode are rolled so that a separator is put between them, and current collecting tabs are connected to active material unformed parts of the anode and cathode. As to a small electrode-rolled battery having a small rated capacity, a strip-type tab is connected to each active material unformed part at each rolling start and each rolling end of the anode and the cathode. As to a large electrode-rolled battery having a large rated capacity, an anode length and a cathode length are longer than those of the small electrode-rolled battery, internal impedance becomes high so as to overheat in vicinities of the tabs since only one tab is connected to each of the cathode and the anode. Therefore, since that is a bad influence on a load characteristic and a cycle lifetime characteristic (that is, a frequency of charge/discharge cycles of the secondary battery repeatedly used until a function of a secondary battery is over), a plurality of tabs are connected to each of the cathode and the anode and a current is collected from a plurality of points.
A large electrode-rolled battery such as this type, conventionally, as shown in
FIG. 12
, is provided with a rolled body
10
and a plurality of tabs (a tab
20
, a tab
21
, a tab
22
, and a tab
23
). The rolled body
10
is stored in a cylindrical case (not shown). The rolled body
10
is formed by rolling a band-shaped anode
11
and a band-shaped cathode
12
so as to put a separator
13
between them. The tab
20
, the tab
21
, the tab
22
, and the tab
23
are respectively connected to four anode active material unformed parts
11
a (after mentioned) in the anode
11
. Similarly, other tabs (not shown) are connected to the cathode
12
.
FIG.
13
A and
FIG. 13B
show the anode
11
in
FIG. 12
, and
FIG. 13A
is a view showing a peripheral surface viewed from an arrow A in FIG.
12
and
FIG. 13B
is a plan unrolled view showing the anode
11
.
As shown in
FIG. 13A
, in the rolled body
10
, a central axis is set as “O”, and a radius is set as “R” when the anode active material unformed parts of the cathode
11
exist in a peripheral surface of the rolled body
10
. As shown in
FIG. 13B
, in the anode
11
, the anode active material forming parts
11
a
are formed in a longitudinal direction of a band-shaped current collector
11
p
intermittently. The tab
20
, the tab
21
, the tab
22
, and the tab
23
are respectively connected to anode active material unformed parts
11
b
between the anode active material forming parts
11
a
. Each the anode active material unformed parts
11
b
is formed at regular intervals and has a regular length. A length L
1
is set as follows:
L
1
<2&pgr;R.
Further, the tab
20
, the tab
21
, the tab
22
, and the tab
23
are connected to a same position of each of the anode active material unformed parts
11
b
. The cathode
12
is formed similarly to the anode
11
.
FIG. 14
is a view showing an essential part of the rolled body
10
indicated by the arrow A in FIG.
12
.
In the rolled body
10
, as shown in
FIG. 14
, the anode
11
and the cathode
12
are rolled in a rolling direction S so that a separator (not shown) is put between the anode
11
and the cathode
12
. To prevent Li+ ions in the anode active material from depositing as metallic lithium between the anode
11
and the cathode
12
, a deviation d
1
is set between a start point of the anode active material unformed part
11
b
and a start point of a cathode active material unformed part
12
b
which is opposite to the anode active material unformed part
11
b
and a deviation d
2
is set between an end point of the anode active material unformed part
11
b
and an end point of the cathode active material unformed part
12
b
which is opposite to the anode active material unformed part
11
b.
The electrode-rolled battery is represented by, for example,
(−) C
n
|LiPF
6
−PC/DEC|Li
1+y
Mn
2
O
4
(+),
where LiPF
6
is lithium, PC is propylene carbonate (electrolyte) and DEC is diethyl carbonate (electrolyte).
A battery reaction is represented by:
Charge
LiMO
2
+CnLi
1−x
MO
2
+C
n
Li
x
,
Discharge
Charge
Li
1
+yMn2O4+CnLi
1
+y−xMn2O4+CnLiX,
Discharge
where LiMO
2
is lithium metallic oxide (anode active material), “M” is Co, Ni or Fe and “C
n
” is carbon material (cathode active material).
FIG. 15A
to
FIG. 22
are process diagrams for explaining a method of manufacturing the electrode-rolled battery shown in FIG.
12
.
Manufacturing process (1) to manufacturing process (8) of the electrode-rolled battery shown in
FIG. 12
will be explained with reference to
FIG. 15A
to FIG.
22
.
(1) Manufacturing process is shown in FIG.
15
A and FIG.
15
B.
As shown in
FIG. 15A
, anode active material forming parts
11
a
, are intermittently provided on one side of the band-shaped current collector
11
p
in the longitudinal direction. Parts except the anode active material forming parts
11
a
are anode active material unformed parts
11
b
. A length of each anode active material unformed part
11
b
is set to length L
1
. Similarly, the anode active material forming parts
11
a
are intermittently provided on another side of the band-shaped current collector
11
p
in the longitudinal direction. As shown in
FIG. 15B
which is a sectional view of
FIG. 15A
taken along a line A—A of
FIG. 15A
, an anode
11
is manufactured in a manner that the anode active material forming parts
11
a
are formed on both sides of the band-shaped current collector
11
p.
(2) Manufacturing process is shown in FIG.
16
A and FIG.
16
B.
As shown in
FIG. 16A
, cathode material forming parts
12
a
are intermittently provided on one side of the band-shaped current collector
12
p
in the longitudinal direction. In this case, parts except the cathode active material forming parts
12
a
are cathode active material unformed parts
12
b
. Similarly, the cathode active material forming parts
12
a
are intermittently provided on another side of the band-shaped current collector
12
p
in the longitudinal direction. As shown in
FIG. 16B
which is a sectional view of
FIG. 16A
taken along a line B—B, a cathode
12
is manufactured in a manner that the cathode active material forming parts
12
a
are formed on both sides of the band-shaped current collector
12
p.
(3) Manufacturing process is shown in FIG.
17
.
A tab
20
, a tab
21
, a tab
22
, and a tab
23
are respectively connected to the anode active material unformed parts
11
b.
(4) Manufacturing process is shown in FIG.
18
.
A tab
30
, a tab
31
, a tab
32
, and a tab
33
are respectively connected to the cathode active material unformed parts
12
b.
(5) Manufacturing process is shown in FIG.
19
.
A separator
13
is put between the anode
11
and the cathode
12
and they are rolled by a rolling apparatus so as to manufacture the rolled body
10
. Incidentally, the tab
30
, the tab
31
, the tab
32
, and the tab
33
are not shown since they are pulled out from another side not a side from which the tab
20
, the tab
21
, the tab
22
, and the tab
23
are pulled out.
(6) Manufacturing process is shown in FIG.
20
.
The tab
20
, the tab
21
, the tab
22
, and the tab
23
are gathered by a manual operation F of an operator. Similarly, the tab
30
, the tab
31
, the tab
32
, and the tab
33
(not shown) are gathered.
(7) Manufacturing process is shown in FIG.
21
.
A collecting heade
Suzuki Hiromi
Watanabe Hideto
Kalafut Stephen J.
NEC Tokin Corporation
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