DESCRIPTION
Title: LiC MODULE
Technical Field
[0001] The present invention relates to a lithium-ion capacitor (LiC)
module.
Background Art
[0002] An LiC module is made up of LiC cells connected together into a
modular
form. The LiC is an electricity storage device combining a negative electrode
of a
lithium-ion secondary battery and a positive electrode of an electrical double
layer
capacitor and is characterized by a considerably high power density.
Citation List
Patent Literature
[0003] PTL 1: Japanese Laid-Open Patent Application Publication No. 2017-
147048
Summary
[0004] The LiC cells forming the LiC module are held by carriers, and the
carriers
holding the LiC cells are stacked on one another. The LiC cells held by the
carriers are
connected to one another via a circuit board. The LiC cells have a
considerably low
internal resistance and allow for instantaneous flow of high currents.
However, the
quality of contact between the LiC cells and the circuit board could vary due
to
dimensional errors of the components of the LiC module. Poor contact between
the LiC
cells and the circuit board lead to increased contact resistance between the
LiC cells and
the circuit board and therefore to reduced performance of the LiC module.
[0005] The present invention has been made in view of the above
circumstances, and
an object of the present disclosure is to provide an LiC module capable of
maintaining
good quality of contact between LiC cells and a circuit board.
[0006] An LiC module according to one aspect of the present disclosure
includes:
LiC cells each of which includes an electrode, the electrode being located at
an upper
portion of the LiC cell; carriers each of which includes a holding frame
holding at least
one of the LiC cells, the carriers being stacked in a predetemiined stacking
direction; and a
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circuit board located above the stacked carriers to electrically connect the
LiC cells to one
another, wherein the electrode of each LiC cell includes a horizontal contact
surface, and
the holding frame of each carrier includes: a frame upper portion including an
electrode
through hole receiving the electrode therethrough; a frame lower portion
located below
and facing the frame upper portion; and a biasing member disposed on the frame
lower
portion and biasing the LiC cell upward to bring the contact surface of the
electrode of the
LiC cell into surface contact with the circuit board.
[0007] With this configuration, the electrodes of the LiC cells can be
brought into and
kept in surface contact with the circuit board. Thus, good quality of contact
between the
LiC cells and the circuit board can be maintained.
[0008] In the LiC module, the biasing member may be a flat spring made of
an elastic
material.
[0009] With this configuration, the biasing member can be formed easily.
[0010] In the LiC module, each carrier may be shaped such that in assembly
of the
LiC module, the LiC cell is inserted into the holding frame through one side
of the holding
frame, the one side facing in the stacking direction, and the biasing member
may be
shaped such that an end portion of the biasing member in the stacking
direction is lower in
height than a central portion of the biasing member in the stacking direction,
the end
portion of the biasing member being located toward the one side of the holding
frame.
[0011] With this configuration, the LiC cells are prevented from being
blocked by the
biasing members in assembly of the LiC module. This facilitates the assembly
of the LiC
cell.
[0012] In the LiC module, one end portion of the biasing member in the
stacking
direction may be fixed to the frame lower portion, and the other end portion
of the biasing
member in the stacking direction may be spaced from the frame lower portion.
[0013] With this configuration, the biasing member can be integral with the
frame
lower portion, and the movable range of the biasing member can be widened.
[0014] In the LiC module, the frame lower portion may include an
interference
avoidance hole extending through a region of the frame lower portion in an up-
down
direction, the region of the frame lower portion being located in
correspondence with the
biasing member.
[0015] With this configuration, interference between the biasing member and
the
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Date Recue/Date Received 2023-07-18
frame lower portion can be avoided during movement of the biasing member in
the up-
down direction.
Advantageous Effects of Invention
[0016] The configuration as described above makes it possible to provide an
LiC
module capable of maintaining good quality of contact between LiC cells and a
circuit
board.
Brief Description of Drawings
[0017] FIG. 1 is an exploded view of an LiC module.
FIG. 2 is a perspective view of LiC cells and a carrier.
Description of Embodiments
[0018] <Overall configuration>
The following will describe an LiC module 100 according to an exemplary
embodiment. The overall configuration of the LiC module 100 will be described
first.
FIG. 1 is an exploded view of the LiC module 100. FIG. 2 is a perspective view
of LiC
cells 10 and a carrier 20. As shown in FIG. 1, the LiC module 100 according to
the
present embodiment includes LiC cells 10, carriers 20, and a circuit board 30.
[0019] As shown in FIG. 2, each LiC cell 10 includes a plate-shaped cell
main body
11 having a given thickness and two electrodes 12 (positive and negative
electrodes)
located at an upper portion of the LiC cell 10. The electrodes 12 are disposed
on the
upper surface of the cell main body 11. Each electrode 12 includes a
cylindrical bolt 13
having a threaded outer circumference and a base 14 to which the bolt 13 is
fixed. The
base 14 includes a horizontal contact surface 15, which is the upper surface
of the base 14.
The bolt 13 and base 14 are integral with each other.
[0020] The carriers 20 serve to hold the LiC cells 10. As shown in FIG. 1,
the
carriers 20 hold the LiC cells 10 in such a manner that the electrodes 12
project out of the
carries 20. In the present embodiment, one carrier 20 holds three LiC cells
10, and the
carriers 20 holding the LiC cells 10 are stacked in a predetermined direction.
The
number of the stacked carriers 20 is not limited to a particular number. For
example, one
LiC module 100 includes a stack of 40 carriers 20. In this case, one LiC
module 100
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Date Recue/Date Received 2023-07-18
includes 120 LiC cells 10. The details of the carriers 20 will be described
later.
[0021] The circuit board 30 serves to electrically connect the LiC cells 10
to one
another. The circuit board 30 is located above the stacked carriers 20. The
lower
surface of the circuit board 30 is provided with wiring to connect all or some
of the LiC
cells 10 in series, and the electrodes 12 of the LiC cells 10 are in contact
with the wiring.
The circuit board 30 includes mounting holes 31 that receive the bolts 13 of
the LiC cells
therethrough. Nuts 32 are brought toward the circuit board 30 from above and
fastened to the bolts 13 received through the mounting holes 31. The fastening
torque of
the nuts 32 is controlled to or below a certain level so as not to deform the
circuit board
30.
[0022] <Details of carriers>
Hereinafter, the details of the carriers 20 will be described. In the
following
description, the direction in which the carriers 20 are stacked will be simply
referred to as
"stacking direction". The near side in the stacking direction of the carriers
20 in FIG. 2
(lower left side in the plane of the figure) will be referred to as "front"
side, and the far
side in the stacking direction in FIG. 2 (upper right side in the plane of the
figure) will be
referred to as "back" side. The direction perpendicular to the stacking
direction and up-
down direction will be referred to as "width direction", and the right and
left sides with
respect to the front side will be referred to as "right" and "left" sides,
respectively.
[0023] Each carrier 20 includes a holding frame 40 holding the LiC cells
10. As
shown in FIG. 2, the holding frame 40 of the present embodiment is
rectangular. The
holding frame 40 includes: an frame upper portion 41 located at the top of the
holding
frame 40 and extending in the width direction; a frame lower portion 42
located at the
bottom of the holding frame 40 and extending in the width direction; a frame
right portion
43 located at the right end of the holding frame 40 in the width direction and
extending in
the up-down direction; a frame left portion 44 located at the left end of the
holding frame
40 in the width direction and extending in the up-down direction; a first
frame
intermediate portion 45 located closer to the right end than the center of the
holding frame
40 in the width direction and extending in the up-down direction; and a second
frame
intermediate portion 46 located closer to the left end than the center of the
holding frame
40 in the width direction and extending in the up-down direction. The frame
upper
portion 41 and the frame lower portion 42 face each other in the up-down
direction. The
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Date Recue/Date Received 2023-07-18
frame right portion 43 and the first frame intermediate portion 45 face each
other in the
width direction. The frame left portion 44 and the second frame intermediate
portion 46
face each other in the width direction. The first frame intermediate portion
45 and the
second frame intermediate portion 46 face each other in the width direction.
[0024] The holding frame 40 includes: a first holding area 47 defined by
the frame
upper portion 41, frame lower portion 42, frame right portion 43, and first
frame
intermediate portion 45; a second holding area 48 defined by the frame upper
portion 41,
frame lower portion 42, first frame intermediate portion 45, and second frame
intermediate
portion 46; and a third holding area 49 defined by the frame upper portion 41,
frame lower
portion 42, frame left portion 44, and second frame intermediate portion 46.
One LiC
cell 10 is inserted into each of the first, second, and third holding areas
47, 48, and 49.
[0025] All of the first, second, and third holding areas 47, 48, and 49 are
open at their
front and back sides. The size of the front opening of each of the holding
areas 47, 48,
and 49 is larger than the size of a cross-section of the cell main body 11 of
the LiC cell 10
taken perpendicular to the stacking direction. The size of the back opening of
each of the
holding areas 47, 48, and 49 is smaller than the size of the cross-section of
the cell main
body 11 of the LiC cell 10 taken perpendicular to the stacking direction. The
dimension
of each of the holding areas 47, 48, and 49 in the width direction is
substantially equal to
the dimension of the LiC cell 10 in the width direction, and the dimension of
each of the
holding areas 47, 48, and 49 in the up-down direction is larger than the
dimension of the
LiC cell 10 in the up-down direction. In assembly of the LiC module 100, the
LiC cells
are inserted into the holding frames 40 through the front sides of the holding
frames 40.
[0026] The frame upper portion 41 of the holding frame 40 includes
electrode
through holes 50 located in correspondence with the electrodes 12 of the LiC
cells 10. In
the present embodiment, two electrode through holes 50 are located in the
region of the
frame upper portion 41 that defines a part of the first holding area 47, two
electrode
through holes 50 are located in the region of the frame upper portion 41 that
defines a part
of the second holding area 48, and two electrode through holes 50 are located
in the region
of the frame upper portion 41 that defines a part of the third holding area
49. Thus, the
frame upper portion 41 includes a total of six electrode through holes 50. The
electrode
through holes 50 are shaped to receive therethrough not only the bolts 13 but
the bases 14
of the electrodes 12. The height (thickness) of the bases 14 is greater than
the thickness
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Date Recue/Date Received 2023-07-18
of the frame upper portion 41. Thus, the contact surfaces 15 of the bases 14
received
through the electrode through holes 50 can be located above the upper surface
of the frame
upper portion 41.
[0027] As shown in FIG. 2, the holding frame 40 includes biasing members 51
disposed on the frame lower portion 42. The biasing members 51 are located at
both
ends of each of the holding areas 47, 48, and 49 in the width direction. The
biasing
members 51 are so-called flat springs and bias the LiC cells 10 upward. The
entire
holding frame 40 is made of an elastic resin material, and the biasing members
51 are
made of the same elastic resin material as the rest of the holding frame 40.
[0028] The biasing members 51 are shaped such that their front and back end
portions
in the stacking direction are lower in height than their central portions in
the stacking
direction. That is, the biasing members 51 are bent such that they are convex
upward
when viewed in the width direction. The back end portions of the biasing
members 51 in
the stacking direction are fixed to the frame lower portion 42, and the front
end portions of
the biasing member 51 are spaced from the frame lower portion 42. That is, one
end of
each biasing member 51 is a fixed end, and the other end of each biasing
member 51 is a
free end. Further, the frame lower portion 42 includes interference avoidance
holes 52
extending through regions of the frame lower portion 42 in the up-down
direction, the
regions of the frame lower portion 42 being located in correspondence with the
biasing
members 51. The biasing members 51 enter the interference avoidance holes 52
when
moved downward.
[0029] In assembly of the LiC module 100, as previously stated, the LiC
cells 10 are
inserted into the holding areas 47,48, and 49 of the holding frame 40 through
the front
sides of the holding areas 47, 48, and 49. The insertion of each LiC cell 10
is done as
follows. The LiC cell 10 is held in a tilted position, the upper portion of
the tilted LiC
cell 10 is inserted into a corresponding one of the holding areas 47, 48 and
49, and the
electrodes 12 are fitted into the electrode through holes 50 from inside the
holding area 47,
48, or 49 such that the electrodes 12 project out of the electrode through
holes 50.
Subsequently, the lower portion of the LiC cell 10 is inserted into the
holding area 47, 48,
or 49. During this insertion, the lower surface of the LiC cell 10 is
subjected to an
upward force applied from the biasing member 51. The lower surface of the LiC
cell 10
is pressed on the biasing member 51 against the upward force to push the
biasing member
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Date Recue/Date Received 2023-07-18
51 downward and thus insert the lower portion of the LiC cell 10 into the
holding area 47,
48, or 49.
[0030] <Advantages>
In the LiC module 100 according to the present embodiment, the biasing
members 51 bias the LiC cells 10 upward as described above, and thus the
contact
surfaces 15 of the electrodes 12 of the LiC cells 10 are brought into and kept
in surface
contact with the circuit board 30. As such, good quality of contact between
the LiC cells
and the circuit board 30 can be maintained. Additionally, the biasing members
51 of
the present embodiment are easy to form because they are so-called flat
springs. Further,
one end of each biasing member 51 of the present embodiment is a fixed end,
and the
other end of each biasing member 51 is a free end. Thus, the biasing members
51 are
movable over a wide range.
[0031] In the LiC module 100 according to the present embodiment, the front
end
portions of the biasing members 51 in the stacking direction are lower in
height than the
central portions of the biasing members 51 in the stacking direction. Thus,
during
insertion of the LiC cells 10 into the holding frame 40 (holding areas 47, 48,
and 49), the
lower portions of the LiC cells 10 are not blocked by the biasing members 51.
Further,
since the biasing members 51 enter the interference avoidance holes 52 of the
frame lower
portions 42 when pushed downward, namely when moved downward, interference
between the biasing members 51 and the frame lower portion 42 can be avoided.
[0032] In the LiC module 100 according to the present embodiment, the back
end of
each biasing member 51 in the stacking direction is a fixed end, and the front
end of each
biasing member 51 in the stacking direction is a free end. However, the back
end in the
stacking direction may be a free end, and the front end in the stacking
direction may be a
fixed end. Further, the biasing members 51 may be other than flat springs
although the
biasing members 51 of the present embodiment are flat springs. For example,
the biasing
members 51 may be so-called coil springs.
Reference Signs List
[0033] 10 LiC cell
12 Electrode
contact surface
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Date Recue/Date Received 2023-07-18
20 carrier
30 circuit board
40 holding frame
41 frame upper portion
42 frame lower portion
50 electrode through hole
51 biasing member
52 interference avoidance hole
100 LiC module
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