Battery module providing for disconnection of an abnormal cell
View Patent ↗A battery module is configured such that n series blocks 20 , each having m cells 10 connected in series, are connected in parallel. Adjacent cells 10 are connected in parallel via a first fusible link 30 . One end of each of the series block 20 is connected to an input/output terminal 50 via a second fusible link 40 . The number m of the cells 10 and the number n of the series blocks satisfy the formulas (1) and (2): m ≦½[ V c /R c ·I f1 −R f1 /R c +3] (1) n ≧( V c +I f2 ·R c )/[V c −( m −1) I f2 ·R c ] (2) where V c and R c represent an electromotive voltage and an internal resistance of the cell 10 , respectively; R f1 and I f1 represent a resistance and a fuse current of the first fusible link 30 , respectively; and I f2 represents a fuse current of the second fusible link 40.
1. A battery module having a plurality of cells arranged in a matrix, wherein
m cells are connected in series in a column direction to form a series block, in which the cells adjacent to each other are connected to each other without a fusible link provided therebetween,
the series block includes n series blocks arranged in a row direction, and the cells adjacent to each other in the row direction are connected in parallel via a first fusible link,
the cell located at one end of each of the series blocks is connected to a common input/output terminal via a second fusible link, and
the number m of the cells arranged in the column direction and the number n of the series blocks arranged in the row direction satisfy the following formulas (1) and (2)
[
formula
1
]
m
≤
1
2
(
V
c
R
c
I
f
1
-
R
f
1
R
c
+
3
)
(
1
)
[
formula
2
]
n
≥
V
c
+
I
f
2
R
c
V
c
-
(
m
-
1
)
I
f
2
R
c
(
2
)
where V c represents an electromotive voltage of the cell; R c represents an internal resistance of the cell; R f1 represents a resistance of the first fusible link; I f1 represents a fuse current of the first fusible link; and I f2 represents a fuse current of the second fusible link.
2. The battery module of claim 1 , wherein
a plurality of battery blocks each of which includes the m×n cells arranged in a matrix are connected in series in the column direction, and
the cell located at one end of each of the battery blocks in the column direction except for the battery block connected to the input/output terminal is connected to a common block connecting member via the second fusible link.
3. The battery module of claim 1 , wherein
the number m of the cells arranged in the column direction and the number n of the series blocks arranged in the row direction satisfy the following formulas (3) and (4), instead of the formulas (1) and (2)
[
formula
3
]
m
≤
1
2
(
V
c
R
c
I
f
1
-
R
f
1
R
c
)
(
3
)
[
formula
4
]
n
≥
m
I
f
2
R
c
V
c
-
m
I
f
2
R
c
(
4
)
where m≧10; n≧10; V c represents an electromotive voltage of the cell; R c represents an internal resistance of the cell; R f1 represents a resistance of the first fusible link; I f1 represents a fuse current of the first fusible link; and I f2 represents a fuse current of the second fusible link.
4. The battery module of claim 1 , wherein the resistance R f1 of the first fusible link is larger than the internal resistance R c of the cell.
5. The battery module of claim 1 , wherein
the cells arranged in the row direction are connected in parallel by a first conductive material, and the first conductive material forms the first fusible link, and
in an event that an internal short-circuit has occurred in the cell, the first conductive material is melted by Joule heat due to a short-circuit current flowing in the cell in which the internal short-circuit has occurred, via the first conductive material.
6. The battery module of claim 5 , wherein
among the cells arranged in the column direction, the cells adjacent to each other in the column direction are connected in series by a second conductive material, and
the first conductive material is connected to the second conductive material connecting the cells adjacent to each other in the column direction.
7. The battery module of claim 6 , wherein
the first conductive material is made of a metal wire or a metal ribbon, and
the metal wire or the metal ribbon is connected to the second conductive material connecting the cells adjacent to each other in the column direction by wire bonding.
8. The battery module of claim 1 , wherein each of the cells is a lithium ion secondary battery.