JP2002075788A - Electric double-layer capacitor and laminate of battery cells - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric double-layer capacitor and a laminate of battery cells for reducing an equivalent series resistance(ESR), by suppressing drying-up of an electrolyte with a thin type. SOLUTION: The battery cell 1 comprises the electrolyte, an ion-permeable insulating porous separator 4, electrode layers 2 and 3 isolated by the separator 4, a noncnductive gasket 5 for holding peripheral parts of the layers 2 and 3, and a current collector 6 for holding the layers 2 and 3 and the gasket 5. In the laminate of the cells 1, a current collector having low gas permeability is used as the external current collector, to suppress the drying-up of the electrolyte, and a current collector having high gas permeability is used as the internal current collector to reduce the ESR of the cell.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laminate of an electric double layer capacitor and a battery cell, and more particularly to a structure of a laminate of an electric double layer capacitor and a battery cell.

[0002]

2. Description of the Related Art Conventionally, electrolytes have been used for electric double layer capacitors and battery cells. In the life of these electric double layer capacitors and battery cells, the ability to hold the electrolyte is an important factor. For this purpose, various measures have been taken to hold the electrolytic solution (suppress the dry-up of the electrolytic solution).

For example, Japanese Patent Application Laid-Open No. 7-240348 discloses a capacitor element of an electric double layer capacitor that suppresses dry-up. FIG.
3 shows a capacitor element of the electric double layer capacitor disclosed in No. 0348. As shown in FIG. 10, a capacitor element 26 of the electric double layer capacitor includes a porous separator 22 that is ion-permeable and insulative, and a pair of separators separated by the porous separator 22 and containing an aqueous electrolyte. A carbon paste electrode layer 24, a non-conductive gasket 25 that holds the periphery of the carbon paste electrode layer 24, and a pair of conductive separators that sandwich the carbon paste electrode layer 24 and the non-conductive gasket 25 from outside 23. The capacitor element 26 suppresses dry-up by forming an amorphous silica particle layer or an alumina particle layer in the fine pores of the porous separator 22 and coagulating the aqueous electrolyte solution.

[0004]

However, in this capacitor element 26, ions are transferred to aggregate the amorphous silica particle layer or alumina particle layer and the aqueous electrolyte solution on the fine pore walls of the porous separator 22. However, there is a problem that the internal resistance in the capacitor element increases.

Japanese Patent Application Laid-Open No. H11-145012 discloses an electric double layer capacitor that suppresses dry-up and reduces the internal resistance in the capacitor element of the electric double layer capacitor. FIG.
5 shows a capacitor element of the electric double layer capacitor disclosed in No. 5012. Capacitor element 31 shown in FIG.
Is a porous separator 32 that is ion-permeable and insulative, and a pair of carbon paste electrode layers 3 separated by the porous separator 32 and having a large number of communication holes.
3, a non-conductive gasket 34 that holds the peripheral end of the carbon paste electrode layer 33, and a pair of conductive separators 35 that sandwich the carbon paste electrode layer 33 and the non-conductive gasket 34 from outside. It is configured. The capacitor element 31 has an electrolyte and a 0.1.
By containing fine particles having a concentration of 1% by weight or more and 5% by weight or less, the path from the center of the electrode to the electrode surface when the electrolytic solution passes through the communication hole is lengthened to suppress dry-up. are doing. Also, this capacitor element 31
In order to prevent the electrolytic solution from aggregating and affecting the mobility of ions, the concentration of the contained fine particles is set to 5% by weight or less with respect to the electrolytic solution, so that the internal resistance of the capacitor element 31 does not increase. .

However, in the capacitor element 31, there is a problem that the capacity per electrode weight is reduced by containing the fine particles.

Japanese Unexamined Patent Application Publication No. 11-340093 discloses an electric double capacitor that suppresses dry-up of an electrolytic solution and reduces equivalent series resistance (hereinafter, referred to as ESR). FIG. 12 shows a capacitor element of an electric double capacitor disclosed in JP-A-11-340093. As shown in FIG. 12, this capacitor element 48
A separator 41 made of an electrically insulating and ion-permeable porous film, a polarizable electrode 42 formed with the separator 41 interposed therebetween, a gasket 43 for holding the separator 41 and the polarizable electrode 42 from the side, A current collector using an electrically conductive rubber sheet or an electrically conductive plastic sheet 46 formed on the outer surface of the polarizable electrode 42 and having an expanded graphite layer 47 on both surfaces (or one surface) of the electrically conductive rubber sheet or the electrically conductive plastic sheet 46 Body 40
And a pair of terminal plates 45. In the capacitor element 48, the gas permeability of the current collector 40 is reduced by the expanded graphite layer 47, so that the dry-up of the electrolytic solution can be suppressed, and the internal resistance does not increase because no fine particles or the like are contained. In addition, the capacitor element 48 reduces the contact resistance with a terminal plate or the like by forming the expanded graphite layer 47 having high adhesion on the current collector surface 40, thereby reducing the E value.
SR can be reduced.

However, this capacitor element 48
However, since the expanded graphite layer 47 is formed, there is a problem that the capacitor element itself becomes thick and the capacity per volume decreases.

In order to suppress the dry-up without reducing the weight per unit volume and volume of the electric double layer capacitor, it is conceivable to use a current collector having a low gas permeability for all the current collectors. Since the current collector with low gas permeability has high resistance of the current collector itself, the ESR of the electric double layer capacitor
Will be higher. On the other hand, if a current collector having a high gas permeability is used for all the current collectors in order to reduce the ESR, the resistance of the current collector itself is low, so that the ESR can be reduced. I will.

In order to solve the above-mentioned conventional problems,
An object of the present invention is to provide an electric double layer capacitor that suppresses a dry-up phenomenon and reduces ESR.

It is another object of the present invention to provide a battery cell stack that suppresses a dry-up phenomenon and reduces ESR.

[0012]

In order to solve the above-mentioned problems, the present invention provides a laminated body of an electric double layer capacitor and a battery cell, wherein a current collector having low gas permeability is used as an external current collector. Thus, the dry-up of the electrolytic solution is suppressed, and the ESR is reduced by using a current collector having high gas conductivity and low resistance of the current collector itself as an internal current collector of the laminate.

According to a first aspect of the present invention, there is provided a separator using an electrolytic solution, a pair of electrode layers separated by the separator, a gasket for holding a peripheral portion of the electrode layer, the electrode layer and the electrode layer. An electric double-layer capacitor in which capacitor elements each having a current collector sandwiching a gasket are stacked in an electrically serial state, wherein the current collectors have different gas permeability.

According to a second aspect of the present invention, there is provided a separator using an electrolytic solution, a pair of electrode layers separated by the separator, a gasket holding a peripheral portion of the electrode layer, the electrode layer and the electrode layer. A battery cell stack in which battery cells each having a current collector sandwiching a gasket are stacked in an electrically connected state, wherein the current collectors have different gas permeability.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a sectional view of the structure of the battery cell of the present invention. As shown in FIG. 1, a battery cell 1 of the present invention comprises a porous separator 4 having ion permeability and insulating property.
And a negative electrode 2 and a positive electrode 3 separated via a porous separator 4, a solid electrolyte, a gel electrolyte, and a molten salt.
An electrode layer, a non-conductive gasket 5 that holds a peripheral end of the electrode layer, and a pair of current collectors 6 that sandwich the non-conductive gasket 5 from the outside around the electrode layer. In this battery cell, the negative electrode 2 comprises a negative electrode active material, a conductive auxiliary, and a binder, and the positive electrode 3 comprises a positive electrode active material, a conductive auxiliary, and a binder.

FIG. 2 is a sectional view showing the structure of the battery cell stack of the present invention. In this battery cell stack 7, 6
A and 6L are external current collectors, and 6B to 6K are internal current collectors. The battery cell stack 7 is obtained by stacking the battery cells 1 shown in FIG. 1 and is characterized by having different gas permeability depending on where the current collectors 6A to 6L are arranged. For example, by using a rubber current collector having a low gas permeability for the external current collectors 6A and 6L, the dry-up of the electrolytic solution is suppressed, and a change in the amount of the electrolytic solution is prevented to improve the cyclability. By using a current collector having a high gas permeability for 6B to 6K, it is possible to suppress an increase in ESR of the battery cell stack. In the present invention, the current collector is not limited to the material, gas permeability, thickness and the like of the current collector, but may be gas permeable as desired by the current collector at the place where it is arranged. Suffice to have different gas permeability.

FIG. 3 shows the structure of a laminated body of battery cells bonded by vulcanization. In this battery cell stack 8, 6A,
6G is an external current collector, and 6B to 6F are internal current collectors. The battery cell stack 8 is obtained by vulcanizing and bonding the stacked battery cells shown in FIG. The current collector in the stacked body 8 of the battery cells is not limited by the material, gas permeability, thickness, etc. of the current collector. What is necessary is to have different gas permeability as shown in FIG.

[0019]

Next, specific examples of the battery cell of the present invention will be described. First, the battery cell stack 7 shown in FIG. 2 will be described. (Example 1) Preparation of a negative electrode and a positive electrode and a film forming method are as described below. The active materials used in the examples are shown in FIGS.
It is shown in FIG. FIG. 4 is a diagram showing a chemical structure of polyindole, and FIG. 5 is a diagram showing a chemical structure of polyphenylquinoxane. In order to form the positive electrode 3, polyindole (see FIG. 4) as an active material and vapor-grown carbon (weight ratio of 4: 1) as a conductive auxiliary were added in a weight ratio of 8%.
A slurry was prepared by adding wt% of a binder resin polyvinylidene fluoride (average molecular weight: 1100). This slurry was sufficiently stirred with a homogenizer, and a film was formed on a current collector sheet using a doctor blade. After film formation, 10
Vacuum dried at 0-150 ° C for 1 hour. After drying, the film was pressed with a roll press to make the electrode film thickness 100 μm. Thereafter, this film was cut into a predetermined shape to obtain a positive electrode 3.

Next, in order to form the negative electrode 2, 8 wt% by weight of polyphenylquinoxaline (see FIG. 3) as an active material and vapor-grown carbon (weight ratio of 3: 1) as a conductive auxiliary were used. Was added to obtain a slurry by adding polyvinylidene fluoride (average molecular weight: 1100). This slurry was sufficiently stirred with a homogenizer, and a film was formed on a current collector sheet using a doctor blade. After the film formation, it was vacuum-dried at 100 to 150 ° C. for 1 hour. The film was pressed with a roll press to make the electrode film thickness 100 μm. Thereafter, this film was cut into a predetermined shape to obtain a negative electrode 2.

Next, an inner diameter of 40 × 24 mm and an outer diameter of 46 × 3
On the upper surface of a 0.2 mm thick ABS non-conductive gasket 5 made of a rectangular sheet stamped and formed to 0 mm,
A current collector 6 made of butyl rubber and having a thickness of 0.2 mm made of a rectangular sheet molded to a size of 46 × 30 mm is arranged.
The edge portion of the gasket 5 and the current collector 6 were bonded with epoxy.

Next, the negative electrode 2, the separator 4, the positive electrode 3, and the current collector 6 were arranged in this order, and the edge of the gasket 5 and the current collector 6 were bonded with epoxy to complete the battery cell 1.

Next, six battery cells 1 are stacked in series,
The upper and lower sides of the laminate were sandwiched in the order of a terminal plate, a rubber plate, and a pressure plate, and were held at a pressure of 10 kg / cm ² to obtain a battery cell laminate 7 (see FIG. 2). The external current collectors 6A, 6A
L has a gas permeability of 1.44 × 10 ⁶ (ml / m ³ · 2
4 h · atm) and a butyl rubber current collector having a thickness of 0.2 mm, and a gas permeability of 1.44 × 1 for the internal current collectors 6B to 6K.
0 thickness 0.1mm by ^{6 (ml / m 3 · 24h} · atm)
Butyl rubber current collector was used.

The result will be described with reference to FIGS. FIG. 6 shows the measurement results of the rate of change in weight of the battery cell stack after elapse of 12 hours at 60 ° C.
The results of ESR measurement at 60 ° C. and cycle test evaluation are shown. The function as a battery can be evaluated from the illustrated ESR measurement and cycle test evaluation. As shown in FIG. 6, the weight change rate at 60 ° C. was 83.5%. As shown in FIG. 7, the ESR before the cycle test was 215 mΩ,
The ESR change rate after 5,000 cycles was 185%, and the 80% initial capacity remaining rate was 11,500 times. This is because the gas permeability of the external current collectors 6A and 6L is small, so that the dry-up of the electrolytic solution is suppressed, and the current collector having a high gas permeability is used for the internal current collectors 6B to 6K to improve ERS. It is thought that it was possible.

Although not shown, the battery cell laminate of the present invention has a thinner internal current collector than the conventional battery cell laminate in which the current collector has a constant thickness. The capacity per volume can be increased. (Embodiment 2) For the purpose of reducing the ESR from the embodiment 1, compared to the embodiment 1, the same external current collectors 6A and 6L are used as they are, and the internal current collectors of 6B to 6K are used. Gas permeability is 2.79 × 10 ⁶ (ml / m ³ · 24h ·
atm) and a current collector having the same film thickness as in Example 1 was carried out.

The result will be described with reference to FIGS. As shown in FIG. 6, the rate of change in weight was approximately equal to 82.8% as compared with Example 1, because the gas permeability of the external current collector was low, so that the dry-up of the electrolytic solution could be suppressed. It is thought that there is. Further, as shown in FIG. 7, the reason why the ESR before the measurement was reduced to 208 mΩ and the ESR change rate after the cycle test was reduced to 153% is because the internal current collector having a high gas permeability was changed. it is conceivable that. The number of cycles (80% of the initial capacity remaining)
9,800 was achieved. (Embodiment 3) For the purpose of further reducing the ESR as compared with the embodiment 2, the external current collector 6
A, 6L use the same thing as it is, and internal current collector 6B
At ~ 6K, the amount of added carbon is increased and the gas permeability is 1.44.
× 10 ⁶ (ml / m ³ · 24 h · atm) and was replaced with a current collector having the same film thickness as in Example 2.

As a result, as shown in FIG. 6, the weight change rate at 60 ° C. was almost equal to 83.9% as compared with Example 2. This is presumably because the gas permeability of the external current collector was low, so that dry-up of the electrolytic solution could be suppressed. In addition, as shown in FIG.
5mΩ and ESR change rate after cycle test is 15
The number of cycles (80% of the initial capacity remaining) could be improved to 11,800 times while being reduced to 9%. This is considered to be because although the gas permeability of the current collector was lower than that in Example 2, the element resistance could be efficiently reduced because the conductivity was increased by increasing the amount of added carbon. . (Embodiment 4) For the purpose of further reducing the ESR as compared with the embodiment 3, the external current collector 6
A, 6L use the same thing as it is, and internal current collector 6B
~ 6K changes the type of rubber to 1.22
The operation was performed by replacing the current collector with a high gas permeability of × 10 ⁸ (ml / m ³ · 24 h · atm) and the same film thickness as in Example 3.

As a result, as shown in FIG. 6, the weight change rate at 60 ° C. was almost equal to 83.1% as compared with Example 3. This is considered to be because the gas permeability of the external current collector was low, so that dry-up of the electrolytic solution could be suppressed. In addition, as shown in FIG.
mΩ and the ESR change rate after the cycle test could be reduced to 167%. This is presumably because the gas permeability was improved by changing the type of rubber. In addition, the number of cycles is 12,3.
00 times were achieved. Fifth Embodiment In comparison with the fourth embodiment, the external current collectors 6A and 6L and the internal collector are compared with the fourth embodiment for the purpose of suppressing the variation in the amount of the electrolyte between cells and further improving the number of cycles. The same current collectors 6B to 6E and 6H to 6K are used as they are, and the intermediate internal current collectors 6F and 6G are 2.79.
The operation was performed by replacing the current collector with a low gas permeability of × 10 ⁶ (ml / m ³ · 24 h · atm) and the same film thickness as in Example 4.

As a result, as shown in FIG. 6, the weight change rate at 60 ° C. was almost equal to 84.1% as compared with Example 4. This is considered to be because the gas permeability of the external current collector was low, so that dry-up of the electrolytic solution could be suppressed. Further, as shown in FIG. 7, the ESR is 210 mΩ,
Although the ESR change rate was slightly inferior to 171%, the number of cycles was 13,000. this is,
By arranging a current collector with low gas permeability in the middle,
This is considered to be because variation in the amount of the electrolyte solution between cells could be suppressed, and thereby the cell voltages could be kept uniform.

Next, Comparative Examples 1 and 2 were carried out in order to understand the effects of the embodiment according to the present invention. (Comparative Example 1) Examples 1 to 4 in which battery cells were laminated with epoxy
In order to make a comparison with the case where all the current collectors of No. 5 used a current collector having a low gas permeability, the gas permeability of 6A to ⁶ L of Example 1 was 1.44 × 10 ⁶ (ml / m ³ · 24h).・ Atm)
Butyl rubber current collector was used. The other manufacturing method is based on Example 1.

As a result, the weight change rate was 89.1%, the ESR before measurement was 294 mΩ, the ESR change rate was 147%, and the number of cycles was 11,700. From this, it can be seen that the dry-up can be suppressed because the gas permeability is lowered, but the ESR becomes a very high value as compared with Examples 1 to 5. (Comparative Example 2) Examples 1 to 4 in which battery cells were laminated with epoxy
In order to compare the case where all the current collectors of No. 5 use a current collector having a high gas permeability, the gas permeability of 6A to 6L of Example 1 was 1.2 × 10 ⁸ (ml / m ³ · 24h Atm) butyl rubber current collector was used. Other manufacturing methods are based on Example 1.

Next, an embodiment of the laminated body of the vulcanized and bonded battery cells shown in FIG. 3 will be described.

As a result, the weight change rate was 67.8%,
Before ESR was 192mΩ, ESR change rate was 587%,
The number of vehicles was 720. This increases gas permeability.
Although the ESR can be reduced due to the reduction, it is compared with Examples 1 to 5.
It can be seen that dry-up cannot be suppressed. (Example 6) Preparation and film formation of a negative electrode and a positive electrode
It carried out like Example 1. Next, inner diameter 40 × 24mm, outer diameter
It is a rectangular sheet punched and formed to 46 x 30 mm.
Non-conductive gas made of unvulcanized butyl rubber with a thickness of 0.2 mm
Formed on the upper surface of the ket 5 to a size of 46 × 30 mm.
Unvulcanized butyl resin with a thickness of 0.2 mm consisting of a rectangular sheet
A current collector 6 made of a rubber is arranged. Next, negative electrode 2, separator
4, positive electrode 3, and current collector 6 (see FIG. 1).
See). Next, six battery cells 1 were stacked in series,
Insert the top and bottom of the laminate in the order of terminal plate, rubber plate, and pressure plate
Only, 10kg / cm ^Two Of battery cells while maintaining pressure
I got a body.

Next, 125 ±
The unvulcanized butyl rubber was vulcanized and bonded in a 5 ° C. temperature atmosphere for 3 hours to obtain a vulcanized and bonded battery cell stack 8 having a withstand voltage of 7.2 V shown in FIG. The external current collectors 6A and 6G have a capacity of 1.44 × 10 ⁶ (ml / m ^3.
A butyl rubber current collector having a thickness of 0.2 mm at 24 h · atm) and a gas permeability of 1.44 × 1 for the internal current collectors 6B to 6F.
0 thickness 0.1mm by ^{6 (ml / m 3 · 24h} · atm)
Butyl rubber current collector was used.

As a result, as shown in FIG. 6, the weight change rate at 60 ° C. was 81.5%. As shown in FIG. 7, the ESR before the cycle test was 203 mΩ, the ESR change rate after 5,000 cycles was 203%, and 80% of the initial capacity (the number of cycles) reached 11,100. Was completed. This is presumably because the gas permeability of the external current collectors 6A and 6G was low, so that dry-up of the electrolytic solution could be suppressed. In addition, although not shown, the battery cell laminate of the present invention has a smaller internal current collector compared to a conventional battery cell laminate having a constant current collector thickness. Capacity can be increased. (Embodiment 7) External current collectors 6A and 6G as compared with Embodiment 6 for the purpose of lowering the ESR than Embodiment 6.
Are used as they are, and the internal current collectors 6B to 6F have a high gas permeability of 2.79 × 10 ⁶ (ml / m ³ · 24 h · atm) and a current collector having the same film thickness. The replacement was performed.

As a result, as shown in FIG. 6, the rate of change in weight at 60 ° C. was almost the same as 80.1%, as compared with Example 6. This is presumably because the gas permeability of the external current collectors 6A and 6G was low, so that dry-up of the electrolytic solution could be suppressed. Further, as shown in FIG. 7, the ESR before the measurement was reduced to 197 mΩ, and the ESR change rate after the cycle test was reduced to 161%. This is presumably because the gas resistance of the internal current collector was increased to reduce the element resistance. The number of cycles was 9,500. (Embodiment 8) In order to further reduce the ESR as compared with Embodiment 7, the same gas permeability is used for the external current collectors 6A and 6G as they are, and the internal current collectors 6B to 6G are used.
6F increases the amount of added carbon and increases the gas permeability to 1.44 ×
The current collector was replaced with a current collector having a thickness of 10 ⁶ (ml / m ³ · 24 h · atm) and the same film thickness as in Example 7.

As a result, as shown in FIG. 6, the weight change rate at 60 ° C. was almost equivalent to 80.9% as compared with Example 7. This is considered to be because the gas permeability of the external current collector was low, so that dry-up of the electrolytic solution could be suppressed. In addition, as shown in FIG.
R was reduced to 191 mΩ, and the ESR change rate after the cycle test was as low as 168%. The number of cycles is 1
It could be improved to 1,700 times. This is presumably because the gas permeability of the current collector was lower than that in Example 6, but the element resistance could be efficiently reduced because the conductivity was increased by increasing the amount of added carbon. . (Example 9) For the purpose of further reducing the ESR as compared with Example 8, the type of rubber was changed, and the same external current collectors 6A and 6G were used as they were,
B to 6F have a gas permeability of 1.22 × 10 ⁸ (ml / m ³
24 h · atm) and a high gas permeability of Example 7
The current was replaced with a current collector having the same thickness.

As a result, as shown in FIG. 6, the weight change rate at 60 ° C. was almost equal to 80.9% as compared with Example 8. This is considered to be because the gas permeability of the external current collector was low, so that dry-up of the electrolytic solution could be suppressed. In addition, as shown in FIG.
R was reduced to 186%, and the ESR change rate after the cycle test was as low as 173%. This is considered to be because the gas resistance of the current collector inside was increased and the resistance of the current collector itself was reduced, so that the element resistance could be reduced. The number of cycles reached 12,000 times. (Embodiment 10) External collectors 6A and 6G and internal collectors 6B and 6B are provided for the purpose of suppressing the variation in the amount of electrolyte between cells and improving the number of cycles as compared with Embodiment 9.
6C, 6E and 6F are the same as those in Example 9, and the intermediate internal current collector 6D is 2.79 × 10 ⁶ (ml /
It was carried out as a current collector having a high gas permeability of (m ³ · 24 h · atm) and the same film pressure as in Example 9.

Compared with the ninth embodiment, as shown in FIG.
Although the SR change rate was slightly inferior, the number of cycles reached 12,700. This is because, by arranging a current collector with low gas permeability in the middle, the variation in the amount of electrolyte between the electric double layer capacitors is suppressed, and the voltage between each electric double layer capacitor can be kept uniform. It is thought that it was possible.

Next, Comparative Examples 3 and 4 were carried out in order to understand the effects of the embodiment according to the present invention. (Comparative Example 3) Example 6 in which battery cells are laminated by vulcanization bonding.
In order to make a comparison with the case where the current collectors having low gas permeability were used for all the current collectors of Nos. 10 to 10, the gas permeability of 1.44 × 10 ⁶ (ml / m ^3. 24h-at
m) butyl rubber current collector was used. The other manufacturing method is based on Example 2.

As a result, the weight change rate was 85.1%, the ESR before measurement was 354 mΩ, the ESR change rate was 165%, and the number of cycles was 11,400. From this, it can be seen that the dry-up can be effectively suppressed because the gas permeability is lowered, but the ESR becomes a very high value as compared with Examples 6 to 10. (Comparative Example 4) Example 6 in which battery cells were laminated by vulcanization bonding.
In order to make a comparison with the case where the current collectors having high gas permeability were used for all the current collectors of Nos. 10 to 10, the gas permeability of 1.2 × 10 ⁸ (ml / m ³ ···) was applied to 6A to 6G of Example 2. 24h-at
m) butyl rubber current collector was used. The other manufacturing method is based on Example 2.

As a result, the weight change rate was 63.5%, the ESR before measurement was 172 mΩ, the ESR change rate was 550%, and the number of cycles was 750. From this, it can be seen that the ESR can be reduced due to the increased gas permeability, but the dry-up cannot be suppressed as compared with Examples 6 to 10.

Finally, in order to easily understand the effects of the present invention, FIG.
2 shows the results of a cycle test at 60 ° C. As shown in the figure, it can be seen that Comparative Example 2 in which a current collector having high gas permeability is used for all rubbers has a remarkable decrease in the number of cycles as compared with the other examples. This is presumably because dry-up could not be suppressed because a current collector having high gas permeability was used as the external current collector. FIG. 9 shows the results of the cycle test at 60 ° C. for Examples 6 to 10 and Comparative Examples 3 and 4. As shown in the figure, Comparative Example 4 in which a current collector having high gas permeability is used for all rubbers has a remarkable decrease in the number of cycles as compared with the other examples. This is presumably because dry-up could not be suppressed because a current collector having high gas permeability was used as the external current collector.

Although only the case where six battery cells are stacked in the embodiment has been described, the number of battery cells to be stacked is not limited to this.

Although the description has been given only of the stacked body of the battery cell, the present invention can be similarly applied to an electric double layer capacitor. Although not shown, the capacitor element of the electric double layer capacitor of the present invention includes a porous separator that is ion-permeable and has insulating properties, a pair of electrode layers separated by the porous separator, and these electrode layers. And a pair of current collectors sandwiching the electrode layer and the non-conductive gasket from outside. When the capacitor elements are stacked as described above, the current collector may have different gas permeability so as to have a desired gas permeability at a place where the capacitor element is arranged.

[0046]

As described above, the first effect of the present invention is to provide a laminated body of an electric double layer capacitor and a battery cell which suppress the dry-up phenomenon and have a small internal resistance.

The reason is that, in the laminate of the electric double layer capacitor and the battery cell, the current collector having a low gas permeability is used as the external current collector to suppress the dry-up of the electrolyte,
This is because a current collector having a high gas conductivity and a low resistance of the current collector itself is used as the internal current collector to reduce the ESR of the stacked body of the electric double layer capacitor and the battery cell.

The second advantage of the present invention is that the capacitance per electrode weight and the capacitance per volume are not reduced.
An object of the present invention is to provide a laminate of an electric double layer capacitor and a battery cell which suppresses a dry-up phenomenon and has a small internal resistance.

The reason is that the dry-up phenomenon is suppressed,
This is because, in order to reduce the internal resistance, the electrode weight is not increased by including fine particles in the electrolytic solution, or the electric double layer capacitor and the battery cell are not thickened by forming an expanded graphite layer on the current collector.

[Brief description of the drawings]

FIG. 1 is a sectional view of a structure of a battery cell of the present invention.

FIG. 2 is a cross-sectional view of the structure of the battery cell stack of the present invention.

FIG. 3 is a cross-sectional view of a vulcanized and bonded battery cell laminate of the present invention.

FIG. 4 shows the chemical structure of polyindole.

FIG. 5 is a view showing a chemical structure of polyphenylquinoxane.

FIG. 6 is a diagram showing measurement results of weight change rates of a battery cell laminate and a vulcanized battery cell laminate.

FIG. 7 is a diagram showing the results of ESR measurement and cycle test evaluation of a battery cell laminate and a vulcanized battery cell laminate.

FIG. 8 is a diagram showing a cycle test result in the case of using the battery cell laminate of the present invention.

FIG. 9 is a diagram showing the results of a cycle test when a vulcanized and bonded battery cell laminate of the present invention is used.

FIG. 10 is a diagram showing a capacitor element of a conventional electric double layer capacitor.

FIG. 11 is a diagram showing a capacitor element of a conventional electric double layer capacitor.

FIG. 12 is a diagram showing a capacitor element of a conventional electric double layer capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery cell 26,31,48 Capacitor element 2 Negative electrode 3 Positive electrode 4,22,32,41 Separator 5,25,34,43 Non-conductive gasket 6 Current collector 7 Battery cell laminated body 8 Vulcanized and bonded battery cell 23, 35 Conductive separator 24, 33, 42 Electrode 45 Terminal plate 46 Conductive rubber sheet 47 Expanded graphite layer

Continued on the front page (72) Inventor Hiroyuki Shima Toru 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Manabu Harada 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Yuji Nakagawa 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation Inside (72) Inventor Shinya Yoshida 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Tomoki Shinda 5-7-1 Shiba, Minato-ku, Tokyo Inside the NEC Corporation (72) Inventor Masato Kurosaki 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation F term (reference) 5H017 AS02 AS06 EE00 HH01 HH03 HH10 5H028 AA01 BB01 CC08 EE00 FF06 HH01 HH05 HH10

Claims (14)

[Claims] 1. A separator using an electrolytic solution, a pair of electrode layers separated by the separator, a gasket holding a peripheral portion of the electrode layer, and a current collector sandwiching the electrode layer and the gasket. An electric double-layer capacitor in which capacitor elements having the following are electrically stacked in series with each other, wherein the current collectors have different gas permeability. 2. The electric double layer capacitor according to claim 1, wherein the current collector for suppressing dry-up of the electrolyte is a current collector having a low gas permeability. 3. The electric double layer capacitor according to claim 1, wherein a thickness of the current collector for suppressing dry-up of the electrolyte is thicker than the other current collector. 4. The electric double layer capacitor according to claim 1, wherein said current collector for reducing ESR has a high gas permeability and a low resistance. 5. The electric double layer capacitor according to claim 1, wherein said current collector for reducing ESR is thinner than said other current collector. . 6. The electric double layer according to claim 1, wherein said current collector for reducing ESR is added with a material for increasing electric conductivity. Capacitors. 7. The current collector according to claim 1, wherein said current collector for suppressing variations in said electrolyte is a current collector having a low gas permeability. Electric double layer capacitor. 8. A separator using an electrolytic solution, a separator, a pair of electrode layers separated by the separator, a gasket holding a peripheral portion of the electrode layer, and a current collector sandwiching the electrode layer and the gasket. A battery cell stack in which battery cells having the following are electrically stacked in a series state, wherein the current collectors have different gas permeability. 9. The battery cell stack according to claim 8, wherein the current collector for suppressing dry-up of the electrolytic solution is a current collector having a low gas permeability. 10. The battery cell stack according to claim 8, wherein a thickness of the current collector for suppressing dry-up of the electrolyte is thicker than the other current collector. . 11. The battery cell stack according to claim 8, wherein the current collector for reducing element resistance has a high gas permeability and a low resistance. 12. The battery cell according to claim 8, wherein the thickness of the current collector for reducing the element resistance is smaller than the thickness of the other current collector. Laminate. 13. The battery cell according to claim 8, wherein said current collector for reducing element resistance is added with a material for increasing conductivity. Laminate. 14. The current collector for suppressing variation in the electrolytic solution is a current collector having a low gas permeability. Of the battery cell.