JP2008072040A - Planar stacked power storage device - Google Patents

Abstract

A low-cost planar stacked power storage device that is easy to dissipate heat without fear of electrical shorting between adjacent cells.
A planar stacked power storage device is configured by inverting a cell's vertical relationship and arranging a positive electrode layer of a cell excluding a cell arranged rearmost in the arrangement direction in a cell adjacent to the arrangement direction. Current collector foil connected to each layer, a fusion resin provided on the surface of the current collector foil between the two cells connected by the current collector foil, and a plurality of cells are sandwiched from above and below. An upper surface container and a lower surface container; a negative electrode terminal connected to a negative electrode layer of a cell arranged in the foremost direction in the arrangement direction; and a positive electrode terminal connected to a positive electrode layer of a cell arranged in the rearmost in the arrangement direction; The upper surface container and the lower surface container are interposed in a gap between the positive electrode layer and the negative electrode layer connected by the current collector foil, and the current collector is provided by the container fusion resin provided on the current collector foil. Fixed to foil.
[Selection] Figure 1

Description

  The present invention relates to a planar stacked power storage device in which a plurality of cells arranged in a plane and electrically connected in series are connected in series.

Examples of the power storage device include an electric double layer capacitor, a lithium ion battery, or a lithium ion capacity.
The electric double layer capacitor is provided with polarizable electrodes (positive electrode and negative electrode) facing each other with a separator interposed therebetween, and utilizes the capacitance of the electric double layer formed on the surface of the polarizable electrode in the electrolytic solution. .
In addition, lithium ion batteries are characterized in that lithium can be stably charged and stored in a carbon negative electrode, and oxides such as cobalt, nickel, and manganese are used for the positive electrode.
In addition, a lithium ion capacitor has been developed as a hybrid type of an electric double layer capacitor and a lithium ion battery, and has a positive electrode of the electric double layer capacitor and a negative electrode of the lithium ion battery, and has a higher voltage than the electric double layer capacitor. On the other hand, the disadvantage is that the voltage cannot be reduced to 0V.

A technique called “planar stacking” is used to increase the voltage of the power storage device. Planar lamination is a method in which a plurality of cells are arranged in a plane and electrically connected in series.
A structure is disclosed in which four circular cells are arranged in a U-shape, and upper or lower current collecting plates are shared between adjacent cells and connected in series (for example, see Patent Document 1).
However, when stacked in a U-shape, the first and fourth cells are adjacent to each other, and the total voltage of the four cells is equal to the charge liquid of the first cell and the electrolysis of the fourth cell. Since it is applied between the liquids, a large voltage difference is applied over a short distance, causing an electrical short circuit. For example, if 2.5 V is applied to one cell, it becomes 10 V for 4 cells, and a large voltage difference is generated between adjacent cells, and a liquid short circuit is likely to occur. When the voltage difference becomes large, liquid short-circuiting is likely to occur at an accelerated rate, and problems such as corrosion may occur particularly frequently between cells having a large voltage difference.

  In view of this, a structure of planar stacks arranged in only one direction and connected in series is disclosed. With this structure, the voltage between adjacent cells is up to 2.5 V, and even if a liquid short circuit occurs, a large current flows and there is little risk of serious corrosion (see, for example, Patent Document 2). .

JP 59-194418 A JP 2002-118037 A

However, in a cell configuration in which a plurality of positive electrodes and negative electrodes are alternately arranged in parallel, a plurality of power storage devices that are collected from the opposite sides of the positive electrode terminal and the negative electrode terminal, each collecting current collector foils, are arranged vertically, The positive electrode terminal and the negative electrode terminal are connected to each other, and the entire structure is merely put in one container. That is, each of the parallel type power storage devices manufactured individually is put in a container, and the positive electrode terminal and the negative electrode terminal are taken out from the opposite sides, and the positive electrode terminal and the negative electrode terminal are connected in a row. Absent. Simply having a single external container does not reduce the number of parts, leading to low costs.
Further, since the current collecting foil is folded and built in each cell, there is a problem that it is difficult to dissipate heat generated in the cell along with charge / discharge. In general, it is known that the power storage device has a faster life deterioration as the use temperature becomes higher. For example, in an electric double layer capacitor, the life is reduced by half every time the temperature rises by 7 ° C.

  An object of the present invention is to provide a low-cost planar stacked power storage device that can easily dissipate heat without fear of electrical shorting between adjacent cells.

  A planar stacked power storage device according to the present invention includes a negative electrode layer and a positive electrode layer facing each other with a separator interposed therebetween, and a plurality of cells impregnated with an electrolyte are arranged in a plane, In a planar stacked power storage device in which cells are electrically connected in series, the cell is arranged by vertically inverting the positive electrode layer and the negative electrode layer of the cell adjacent to the positive electrode layer and the negative electrode layer. A negative electrode terminal connected to the negative electrode layer of the cell part at one end in the arrangement direction, a positive electrode terminal connected to the positive electrode layer of the cell part at the other end in the arrangement direction, The pair of positive electrode layers adjacent to each other in the arrangement direction in the positive electrode layer and the negative electrode layer excluding the negative electrode layer connected to the negative electrode terminal at the other end and the positive electrode layer connected to the positive electrode terminal at the other end And above A current collector foil for connecting each of the electrode layers; a container fusion resin provided on a surface of the current collector foil between the two cells connected by the current collector foil; A container current collector foil fusion resin provided on a surface of the current collector foil opposite to the surface in contact with the cell; and an upper surface container and a lower surface container for sandwiching the plurality of cells from above and below. And the lower surface container includes a container fusion resin and a container current collector foil provided on the surface of the current collector foil such that a partition wall is provided between a side surface of the cell and a side surface of an adjacent cell facing the side surface. It is fixed to the current collector foil by a fusion resin.

  The effect of the planar laminated power storage device according to the present invention is that the structure in which the positive electrode layer and the negative electrode layer are provided on the same surface of the current collector foil with the container fusion resin sandwiched between them is a main component that is repeated. Configuration assembly is possible at low cost. Moreover, since the electrode of an adjacent cell is isolated by the container fusion resin and the container current collector foil fusion resin, a liquid short circuit is prevented.

Embodiment 1 FIG.
1 is a longitudinal sectional view of an electric double layer capacitor according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the electric double layer capacitor according to the first embodiment. 1 is a cross-sectional view taken along a line AA in FIG. 2 is a cross-sectional view taken along the line BB in FIG.
An electric double layer capacitor will be described as an example of the planar stacked power storage device according to the first embodiment of the present invention, but the present invention is not limited to this, and the present invention can be similarly applied to a lithium ion battery and a lithium ion capacitor. In the electric double layer capacitor according to the first embodiment of the present invention, a plurality of cells 4 are arranged in a line in a plane. In the first embodiment, seven cells 4a to 4g are arranged, but the number of cells 4 is not limited to this.

The cell 4 is impregnated with an electrolyte solution (not shown) and an electric double layer is formed at the interface with the electrolyte solution. The positive electrode layer 1 and the negative electrode layer 2, and the positive electrode layer 1 and the negative electrode layer 2 are electronically connected. The separator 3 is insulated and can pass only ions. The positive electrode layer 1 and the negative electrode layer 2 have a planar outer shape in which the length of the side perpendicular to the arrangement direction when the cells 4 are arranged in the plane is twice the length of the side parallel to the arrangement direction. It is the above rectangle. The outer shape of the separator 3 is a rectangle wider than the outer shape of the positive electrode layer 1. When the separator 3 is sandwiched between the positive electrode layer 1 and the negative electrode layer 2, one side parallel to the arrangement direction protrudes from the side surfaces of the positive electrode layer 1 and the negative electrode layer 2 by a predetermined length.
The cell 4 has an electrolyte reservoir 19 that sandwiches the separator 3 protruding from the side surfaces of the positive electrode layer 1 and the negative electrode layer 2 from above and below.

  In the electric double layer capacitor according to the first embodiment, the cells 4 are arranged with a gap so that the vertical relationship between the positive electrode layer 1 and the negative electrode layer 2 is alternately reversed in the arrangement direction. In order to electrically connect the cells 4 in series, the positive electrode layer 1 of the cell 4a arranged in the foremost direction in the arrangement direction and the negative electrode of the cell 4b arranged adjacent to the arrangement direction of the cell 4a Layer 2 is connected by current collector foil 11. Further, the positive electrode layer 1 of the cell 4b is connected to the negative electrode layer 2 of the cell 4c arranged adjacent to the arrangement direction of the cell 4b by the current collector foil 11. Similarly, the positive electrode layer 1 of the cells 4c, 4d, 4e, and 4f is the negative electrode layer 2 of the cells 4d, 4e, 4f, and 4g arranged adjacent to each other in the arrangement direction of the cells 4c, 4d, 4e, and 4f, respectively. And the current collector foil 11.

Further, the negative electrode layer 2 of the cell 4 a arranged in the foremost side in the arrangement direction is connected to the negative electrode terminal 14. Further, the positive electrode layer 1 of the cell 4 g arranged at the rearmost side in the arrangement direction is connected to the positive electrode terminal 13.
A positive terminal hole 22 and a negative terminal hole 23 provided in the positive terminal 13 and the negative terminal 14 are bolt holes to which current terminals connected to an external load are attached.
A container fusion resin 10 is formed on the current collector foil 11 facing the gap between the cells 4.

  The electric double layer capacitor according to the first embodiment includes an upper surface container 6 and a lower surface container 9 that sandwich a plurality of cells 4 in the vertical direction. And the upper surface container 6 is provided with the hollow 7 which accommodates two cells 4 from the near side of the arrangement direction. The height of the side wall of the recess 7 is slightly smaller than the sum of the thickness of the cell 4 and the thickness of the current collector foil 11. When the cell 4 is stored in the upper surface container 6, the cells 4a and 4b are stored in the recess 7a, the cells 4c and 4d are stored in the recess 7b, and the cells 4e and 4f are stored in the recess 7c.

In addition, the lower surface container 9 is provided with a recess 8 that accommodates two cells 4 from the rear in the arrangement direction. The height of the side wall of the recess 8 is the same as the height of the recess 7. When the cell 4 is stored in the lower surface container 9, the cells 4b and 4c are stored in the recess 8a, the cells 4d and 4e are stored in the recess 8b, and the cells 4f and 4g are stored in the recess 8c.
Since the positive electrode layer 1 and the negative electrode layer 2 have a short width in the arrangement direction and a long width in the direction orthogonal to the arrangement direction, the length in the arrangement direction is extremely long even if a plurality of cells are arranged in the arrangement direction. Can be prevented.

FIG. 3 is an enlarged view of a portion C in FIG. In the upper surface container 6 and the lower surface container 9, when the cells 4 connected by the current collector foil 11 are stored in the upper surface container 6 and the lower surface container 9, the position where the current collector foil 11 overlaps the container fusion resin 10 spreads outward. Thus, a gap is formed between the upper surface container 6 and the lower surface container 9 and the current collector foil 11. The upper surface container 6 and the current collector foil 11, and the lower surface container 9 and the current collector foil 11 are fused by filling the gap with the container current collector foil fusion resin 24.
In this way, the current collector foil 11 and the upper surface container 6 or the lower surface container 9 are fused by the container fusion resin 10, and the current collector foil 11 and the upper surface container 6 or the lower surface container 9 are fused by the container current collector foil fusion resin 24. And is integrated on a straight line in the vertical direction, and a partition is provided between the side surface of the cell 4 and the side surface of the adjacent cell 4 facing the side surface, so that the electrolyte does not short-circuit between adjacent cells. ing.

When the cells 4 are stored in the upper and lower containers 6 and 9 from above and below, the side surfaces except the side surfaces of the cells 4 that contact the electrolyte reservoir 19 are gathered together with the upper end surfaces of the recesses 7 and 8 as shown in FIG. The electric foil 11 is fused with the container fusion resin 10 to be separated from the adjacent cells 4.
Between adjacent electrolyte reservoirs 19, a communication passage 20 is formed in which the gas and liquid sandwiched between the upper surface container 6 and the lower surface container 9 can communicate. Further, an electrolyte solution injection port 21 is provided in a portion of the lower surface container 9 facing the electrolyte solution reservoir 19 of the cell 4a closest to the arrangement direction.

FIG. 4 is an enlarged cross-sectional view taken along line D in FIG. There is no container fusion resin 10 in the gas communication passage 20, and the electrolyte overflowing the electrolyte reservoir 19 can move to the adjacent cell 4.
In addition, when the electrolytic solution is injected after evacuating the inside of the container from the electrolytic solution injection port 21, the electrolytic solution is supplied to the electrolytic solution reservoir 19 through each gas communication passage 20 in each cell 4, The electrolytic solution is supplied from the electrolytic solution reservoir 19 to the separator 3, and the electrolytic solution is supplied from the separator 3 to the positive electrode layer 1 and the negative electrode layer 2.
Thereafter, the electrolyte inlet 21 made of a thermoplastic resin such as polyethylene is sealed and used. However, since the excess electrolyte is stored in the electrolyte reservoir 19, the electrolyte overflows and gasses. There is no worry of flowing through the communication passage 20 to the adjacent cell.

  In addition, since the electrolyte is absorbed by the positive electrode layer 1 and the negative electrode layer 2 during charging and released during discharge, the electrolyte may overflow during discharge, but the voltage is close to zero during discharge. Therefore, even if the electrolytic solution accumulates in the gas communication passage 20, there is little risk of current flowing due to a short circuit of the electrolytic solution. Since the excess or deficiency of the electrolyte is buffered by the electrolyte reservoir 19, there is little possibility that the electrolyte will accumulate in the gas communication passage 20 in the vicinity thereof.

  The gas communication passage 20 functions to keep the gas pressure in the container constant by releasing the gas to an adjacent cell when gas is generated in a part of the cells connected in series and the internal pressure of the container is increased. To do. When the upper surface container 6 and the lower surface container 9 are fused using the container fusion resin 10, the gas communication passage 20 can be easily configured by not providing the container fusion resin 10 only in that portion. .

  In this way, the structure in which the positive electrode layer 1 and the negative electrode layer 2 are provided on the same surface of the current collector foil 11 with the container fusion resin 10 sandwiched between them is a simple combination of repeated parts. Since it is symmetrical, the main structure of planar stacking can be constructed with basically one structure.

FIG. 5 is a plan view showing a manufacturing process for forming positive electrode layer 1, negative electrode layer 2, and container fusion resin 10 on current collector foil 11 of the electric double layer capacitor according to Embodiment 1 of the present invention.
Next, the manufacturing process of forming the positive electrode layer 1, the negative electrode layer 2, and the container fusion resin 10 between them on one surface of the current collector foil 11 will be described.
In this manufacturing process, a doctor coater method is used, and the positive electrode layer paste dam 30 and the negative electrode layer paste dam 31 are arranged on the doctor roll 28 with a predetermined distance therebetween. Then, the thickness is controlled by the doctor roll 28 and the paste adheres to the coating roll 27, and the paste is transferred onto the roll-collecting current collector foil 26. By drying the paste thus transferred, the positive electrode layer coating part 32 and the negative electrode layer coating part 33 having a predetermined gap can be formed by a single coating.
Then, the resin bonding part 34 is formed by applying the container fusion resin 10 to the gaps in the current collector foil 26. A state of the current collector foil 26 thus manufactured is shown in FIG.
Next, the container current collector foil fusion resin 24 is applied to the back surface of the resin pasting portion 34 of the current collector foil 26 thus manufactured to form the resin application portion 35. The state of the current collector foil 26 with the resin coating portion 35 formed in this way is shown in FIG.

  Next, as shown in FIG. 6, a current collector foil 11 in which the positive electrode layer 1 and the negative electrode layer 2 are formed on the same surface is manufactured using a punching die having a two-dot chain line. Then, a predetermined number of current collector foils 11 are arranged in the arrangement direction so that the positive electrode layer 1 and the negative electrode layer 2 appear in the table. At this time, the positive electrode layers 1 and the negative electrode layers 2 are alternately arranged in the arrangement direction. Note that the negative electrode layer 2 and the positive electrode layer 1 corresponding to the positive electrode layer 1 of the current collector foil 11 closest to the arrangement direction and the negative electrode layer 2 of the current collector foil 11 rearmost in the arrangement direction exist. Absent.

  Next, the separator 3 is disposed so as to cover the positive electrode layer 1 and the negative electrode layer 2. Then, another punched current collecting foil 11 is arranged so that the positive electrode layer 1 and the negative electrode layer 2 are in contact with the separator 3. At this time, it arrange | positions so that the positive electrode layer 1 and the negative electrode layer 2 may oppose through the separator 3. FIG.

In this way, the positive electrode layer coating portion 32 and the negative electrode layer coating portion 33 can be simultaneously formed on the current collector foil 26, and the resin pasting portion 34 can be subsequently formed, and a repeat part is produced by punching with a punching die. Since it can, it can be manufactured easily.
The current collector foil 11 on which the positive electrode layer 1, the negative electrode layer 2, and the container fusion resin 10 are thus formed is prepared as repeat parts, and the cells 4 can be arranged by arranging them on a plane. Therefore, the assembly of the cell 4 is easy.

  A plurality of cells 4 thus planarly laminated are sandwiched between aluminum laminate films from above and below, and the container fusion resin 10 is heated to fuse the resin, thereby producing the electric double layer capacitor having the configuration shown in FIG. be able to.

Embodiment 2. FIG.
FIG. 7 is a plan view of an electric double layer capacitor according to Embodiment 2 of the present invention. FIG. 8 is a longitudinal sectional view taken along the line AA of FIG. FIG. 9 is a longitudinal sectional view taken along line BB in FIG.
The electric double layer capacitor according to the second embodiment of the present invention is different from the electric double layer capacitor according to the first embodiment in that a cooling fin 37 is added. The same reference numerals are added and description thereof is omitted.
The cooling fins 37 are made of aluminum, and as shown in FIG. 8, the electric double layer capacitor according to the first embodiment is sandwiched between the upper surface container 6 and the pressing plate 38 made of aluminum from the outside of the lower surface container 9. When pinching and fixing, the bolt 40 is passed through the bolt hole 39 provided in the cooling fin 37 and the holding plate 38 and tightened by the nut 36.

  In the electric double layer capacitor according to the second embodiment, as shown in FIG. 9, the side opposite to the side where the electrolyte reservoir 19 of the separator 3 is provided extends and is bent to the side surface of the positive electrode layer 1. The separator bent portion 41 serves as a substitute for the electrolyte reservoir 19 while preventing an electrical short circuit between the positive electrode layer 1 and the negative electrode layer 2.

Thus, since the cooling fin 37 is attached so that it may closely_contact | adhere to the upper surface container 6 of an electric double layer capacitor, the heat | fever which generate | occur | produced in the cell 4 by charging / discharging can be discharge | released rapidly outside.
Moreover, since the cooling fin 37 and the pressing plate 38 are fastened by the bolt 40 and the nut 36, the contact thermal resistance between the electric double layer capacitor and the cooling fin 37 can be reduced.
In the second embodiment, the cooling fins 37 are provided only on one side, but they may be provided on both sides.

Embodiment 3 FIG.
FIG. 10 is a cross-sectional view when the electric double layer capacitor according to Embodiment 3 of the present invention is attached to the motor body.
Since it can be bent at the portion of the current collector foil 11 on which the container fusion resin 10 is formed, it can be attached so as to surround the outer periphery of the motor body 42 having a circular outer shape, and the wiring with the motor can be shortened. In addition to performing power assist and energy regeneration, heat radiation cooling can be performed.

Embodiment 4 FIG.
FIG. 11 is a cross-sectional view when an electric double layer capacitor according to Embodiment 4 of the present invention is attached to a device case.
In this fourth embodiment, the portion of the current collector foil 11 on which the container fusion resin 10 is formed is bent 90 degrees, and is attached to the inner wall of the device case 43 to cool and radiate heat while securing the space of the device. it can.

Embodiment 5. FIG.
FIG. 12 is a cross-sectional view of an electric double layer capacitor according to Embodiment 5 of the present invention.
In the fifth embodiment, a highly laminated electric double layer capacitor can be obtained more compactly by folding and overlapping 90 degrees at the portion of the current collector foil 11 on which the container fusion resin 10 is formed.
Further, by folding through the cooling fins 37, a highly laminated electric double layer capacitor that can be easily cooled can be obtained.

It is a longitudinal cross-sectional view of the electric double layer capacitor concerning Embodiment 1 of this invention. It is a cross-sectional view of the electric double layer capacitor according to the first embodiment of the present invention. It is an expanded sectional view of the C section of FIG. It is an expanded sectional view in the D sectional line of FIG. It is a top view which shows the manufacturing process which coats a positive electrode layer and a negative electrode layer on a current collection foil with a doctor coater method. It is a top view of the state which affixed adhesive resin on the front and back of the roll-winding current collection foil continuously coated. It is a top view of the electric double layer capacitor concerning Embodiment 2 of this invention. It is sectional drawing in the AA cross section of FIG. It is sectional drawing in the BB cross section of FIG. It is sectional drawing when the electric double layer capacitor concerning Embodiment 3 of this invention is attached to the motor main body. It is sectional drawing when the electric double layer capacitor concerning Embodiment 4 of this invention is attached to the inner wall of an apparatus case. It is sectional drawing of the electric double layer capacitor concerning Embodiment 5 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Positive electrode layer, 2 Negative electrode layer, 3 Separator, 4 cells, 6 Upper surface container, 7, 8 hollow, 9 Lower surface container, 10 Container fusion resin, 11 Current collector foil, 13 Positive electrode terminal, 14 Negative electrode terminal, 19 Electrolysis Liquid reservoir, 20 communication passage, 21 electrolyte inlet, 22 positive terminal hole, 23 negative terminal hole, 24 container collector foil fusion resin, 26 collector foil, 27 coating roll, 28 doctor roll, 30 positive electrode layer paste Dam, 31 Negative electrode layer paste dam, 32 Positive electrode layer coating part, 33 Negative electrode layer coating part, 34 Resin pasting part, 35 Resin coating part, 36 Nut, 37 Cooling fin, 38 Holding plate, 39 Bolt hole , 40 bolts, 41 bent portion, 42 motor body, 43 device case.

Claims (6)

A planar laminate composed of a negative electrode layer and a positive electrode layer facing each other with a separator, in which a plurality of cells impregnated with an electrolyte solution are arranged in a plane, and the plurality of cells are electrically connected in series Type power storage device,
The cell is arranged by vertically inverting the positive electrode layer and the negative electrode layer of the cell where the positive electrode layer and the negative electrode layer are adjacent,
A negative electrode terminal connected to the negative electrode layer of the cell portion at one end in the arrangement direction;
A positive electrode terminal connected to the positive electrode layer of the cell part at the other end in the arrangement direction;
The pair of positive electrodes adjacent to each other in the arrangement direction in the positive electrode layer and the negative electrode layer excluding the negative electrode layer to which the negative terminal at one end is connected and the positive electrode layer to which the positive terminal at the other end is connected A current collector foil for connecting the electrode layer and the negative electrode layer respectively;
A container fusion resin provided on the surface of the current collector foil between the two cells connected by the current collector foil and in contact with the cell;
A container current collector foil fusion resin provided on the surface of the current collector foil opposite to the surface in contact with the cell;
An upper surface container and a lower surface container that sandwich the plurality of cells from above and below;
With
The upper surface container and the lower surface container include a container fusion resin and a container provided on the surface of the current collector foil so that a partition wall is provided between a side surface of the cell and a side surface of an adjacent cell facing the side surface. A flat laminated power storage device, which is fixed to the current collector foil by a current collector foil fusion resin.   2. The planar stacked type according to claim 1, wherein the length of the side perpendicular to the arrangement direction of the positive electrode layer and the negative electrode layer is at least twice the length of the side parallel to the arrangement direction. Power storage device. The separator is projected on a horizontal side surface in the arrangement direction of the positive electrode layer,
The planar stacked power storage device according to claim 1, wherein an electrolyte reservoir for storing an electrolyte is provided on the protruding separator.   The communication path which can connect the gas and liquid which were pinched | interposed into the said upper surface container and the said lower surface container between the said adjacent electrolyte reservoirs was provided, The Claim 1 thru | or 3 characterized by the above-mentioned. Planar stacked power storage device.   5. The planar stacked power storage device according to claim 1, wherein an electrolyte inlet is provided in an electrolyte reservoir of an end cell. 6.   The planar stacked power storage device according to claim 1, wherein cooling fins are provided on the upper surface container or the lower surface container.

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