JP2009289766A - Electric double-layer capacitor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric double-layer capacitor module comprising a plurality of electric double-layer capacitor cells put in a storage case, for overcoming deterioration in performance such as static capacitance and internal resistance due to repetition of charging and discharging. <P>SOLUTION: The electric double-layer capacitor module includes the plurality of electric double-layer capacitor cells put in the storage case equipped with partitions fixed at predetermined intervals so that one cell is put per gap between the respective partitions. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric double layer capacitor module in which a plurality of electric double layer capacitor cells that store electricity in an electric double layer that is an interface between a polarizable electrode such as activated carbon and an electrolytic solution are arranged in a storage case.

  In recent years, an electric double layer capacitor that accumulates electricity in an electric double layer that is an interface between a polarizable electrode such as activated carbon and an electrolytic solution has been put into practical use as a power storage medium. As a general configuration of an electric double layer capacitor, an electric sheet having a configuration in which a current collector such as a metal foil and a polarizable electrode such as activated carbon and separators are alternately laminated and impregnated with an electrolytic solution. A multilayer capacitor is formed, and the electric double layer capacitor is sealed in a container to form an electric double layer capacitor cell.

  In addition, an electric double layer capacitor cell is manufactured by forming a laminate of an electrode sheet and a separator in a sandwich shape in a square electric double layer capacitor and in a roll shape in a cylindrical electric double layer capacitor. After connecting the lead part of the body (positive electrode body and negative electrode body) to each terminal and storing the laminated body in a container, the electrolytic solution is injected from the opening of the container to impregnate the laminated body with the electrolytic solution, and the electrode terminal Many methods have been implemented to seal the container with its tip exposed to the outside.

  In a square electric double layer capacitor, usually, a plurality of electric double layer capacitor cells are arranged in a storage case so that the surface of the laminated body faces each other, and used as an electric double layer capacitor module. In the case of an electric double layer capacitor, when there is no external pressure, the laminate (activated carbon contained in the polarizable electrode) expands during charging, and the laminate (activated carbon contained in the polarizable electrode) during discharge. ) Shrinks, and it is known that this repetition leads to performance degradation such as capacitance and internal resistance. For example, an electric double layer capacitor module having a function of applying pressure to the surface of the laminate has been developed. ing.

JP 2002-289485 A JP 2003-1224075 A JP 2003-133190 A JP 2003-272967 A Japanese Patent Laid-Open No. 2004-296156

However, even an electric double layer capacitor module provided with a function of pressing toward the laminate surface could not significantly improve performance degradation such as capacitance and internal resistance due to repeated charging and discharging.
Therefore, the problem to be solved by the present invention is that in an electric double layer capacitor module in which a plurality of electric double layer capacitor cells are arranged in a storage case, the electric power that can greatly improve performance degradation due to repeated charge and discharge. It is to provide a multilayer capacitor module.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have applied a method of applying pressure from both ends of a plurality of electric double layer capacitor cells arranged in series to each electric double layer capacitor cell. Equally difficult to pressurize. For example, in the electric double layer capacitor cell at the center and at the end, there are significant differences in performance such as capacitance and internal resistance during use, and electric double layer capacitor cell. Rather than pressurizing the laminate toward the surface of the laminate, it is possible to stably and significantly suppress performance degradation due to repeated charge and discharge by maintaining a certain cell (laminate) width by providing a partition, and further, the partition ( Preferably, the partition having good thermal conductivity or the partition having the heat radiation means) allows the heat of the electric double layer capacitor cell generated during rapid charge / discharge to be easily released. Found that such can suppress the performance degradation, it reaches the electric double layer capacitor module of the present invention.

  That is, according to the present invention, a plurality of electric double layer capacitor cells having a structure in which an electrode sheet composed of a current collector and a polarizable electrode and separators are alternately laminated and impregnated with an electrolytic solution are fixed at predetermined intervals. It is an electric double layer capacitor module characterized by being arranged in the storage case which has the partition provided in this way so that it may become one each in the gap of each partition.

  In the electric double layer capacitor module of the present invention, a plurality of electric double layer capacitor cells are fixed by a partition so as to have a constant cell (laminate) width one by one. The variation in pressure applied to the electric double layer capacitor cell in such an electric double layer capacitor module is small, and it is possible to greatly improve performance degradation such as capacitance and internal resistance due to repeated charge and discharge. Furthermore, since the heat of the electric double layer capacitor cell generated during charging and discharging can be easily released by partitioning, it is possible to suppress the performance deterioration due to the temperature rise of the electric double layer capacitor cell.

  In the present invention, a plurality of electric double layer capacitor cells having a structure in which an electrode sheet composed of a current collector and a polarizable electrode and separators are alternately laminated and impregnated with an electrolytic solution are arranged in a storage case. This is applied to the electric double layer capacitor module. In particular, an excellent effect is obtained when an electric double layer capacitor cell including activated carbon that expands by charging (expansion rate of 10% or more) as a constituent component of the current collector or an electric double layer capacitor cell that rapidly charges and discharges is stored. Demonstrate.

  Hereinafter, although the electric double layer capacitor module of this invention is demonstrated in detail based on FIGS. 1-5, this invention is not limited by these. 1 is a configuration diagram showing an example of the electric double layer capacitor module of the present invention, FIG. 2 is a perspective view showing an example of a storage case used in the electric double layer capacitor module of the present invention, and FIG. 3 is a storage of FIG. FIG. 4 is a perspective view showing an example of a partition according to the present invention, and FIG. 5 is a perspective view showing an example of a laminated body of electric double layer capacitor cells according to the present invention. .

As shown in FIG. 1, an electric double layer capacitor module (a set cell of electric double layer capacitors) according to the present invention includes a partition 2 in which a plurality of electric double layer capacitor cells 1 are fixed at predetermined intervals. It is an electric double layer capacitor module which is arranged in the storage case 3 having one in the gap between the partitions.
As the storage case 3 used in the present invention, for example, the one assembled as shown in FIG. 2 using each component such as the partition 2, the bolt 4, and the spacer 5 as shown in FIG. 3 can be used. Note that a spacer having an appropriate thickness can be used for the end portion.

  The material of each of these components is not particularly limited as long as the electric double layer capacitor cell can be pressed with a relatively high pressure, and a metal material such as stainless steel, ceramic, plastic, or the like may be used. However, it is preferable to use a metal material for the spacer in that the heat of the electric double layer capacitor cell generated during charging and discharging can be easily released. Further, in order to efficiently release heat, a partition having a heat radiating means (for example, a hollow portion 6 as shown in FIG. 4) can be used. In the case where such a heat dissipating means is provided, no voids or irregularities are provided on the surface facing the laminate. As other heat dissipation means, the partition and spacer may be made of a metal material, and means for cooling the spacer at the end (water cooling, air cooling, etc.) may be provided outside the spacer. The heat dissipating means is particularly effective when the spacer is other than metal. In addition, the magnitude | size of the partition 2 is about 1.05 to 3 times of a laminated body both vertically and horizontally. Further, the thickness of the partition 2 is appropriately set depending on the mechanical strength of the material used, and is not particularly limited.

  The gap between the partitions is set by a spacer having a predetermined thickness. The electric double layer capacitor cell may be placed in the storage case before the partition and the spacer are fixed, or after the partition and the spacer are fixed. The storage case shown in FIG. 2 has a configuration in which three electric double layer capacitor cells can be arranged. However, the present invention is not limited to this. For example, about 2 to 100 electric double layer capacitor cells are provided. It is good also as a storage case which can be arranged.

  The electric double layer capacitor cell used in the electric double layer capacitor module of the present invention has a configuration in which electrode sheets composed of current collectors and polarizable electrodes and separators are alternately laminated and impregnated with an electrolyte. The structure is not particularly limited as long as it is housed in a flat container. For example, it is manufactured as follows.

  Laminates usually consist of a positive electrode body in which an aluminum foil is bonded to a polarizable electrode made of a mixture containing activated carbon, carbon black, and the like, and a negative electrode body in which an aluminum foil is bonded to a polarizable electrode. Alternatively, as shown in FIG. 5, the lead portion 8 of the positive electrode body and the lead portion 9 of the negative electrode body can be connected to the electrode terminals, respectively, as shown in FIG. A total of 10 to 100 sheets are laminated so as to form a square or rectangular laminate having a side of about 50 to 200 mm. Such a laminate 7 is usually bonded to the lead portion 8 of the positive electrode body and the positive electrode terminal 10 and to the lead portion 9 of the negative electrode body and the negative electrode terminal 11.

  Moreover, the constituent material of the container for storing the laminate as described above is usually one in which the surface of a metal foil such as an aluminum foil is covered with a heat-meltable plastic film. When storing the laminated body, the peripheral part excluding the opening part for storing two sheets of sheets of a metal foil having a square or rectangular shape coated with a heat-meltable plastic film in advance. Are pressure-bonded to form a bag. These laminates and containers are dried or dried under reduced pressure in order to remove moisture and the like to an extremely low concentration, and then the laminate is accommodated in the container so that the electrode terminals are on the opening side of the container.

  Next, an electrolytic solution is injected from the opening of the container, and then the inside of the container is decompressed, and the laminate is decompressed. By this decompression treatment, the gas adsorbed on the polarizable electrode such as activated carbon is removed, and the laminate can be efficiently impregnated with the electrolytic solution. In addition, if necessary, between the injection of the electrolyte and the sealing of the container, the electrode terminal is energized and subjected to electrolytic purification in order to electrolyze and remove moisture and functional groups contained in the polarizable electrode. You can also. After the laminate is depressurized, the container is sealed by pressing, for example, two heated heat seal bars with the opening of the container interposed therebetween, and an electric double layer capacitor cell is obtained.

The time when the electric double layer capacitor is placed in the storage case as shown in FIG. 2 is that the container is sealed after the stacked body is stored in the container so that the electrode terminals are on the opening side of the container. It may be performed before the electric double layer capacitor cell is completed, or after the electric double layer capacitor cell is completed.
Moreover, in this invention, it is performed in the dry gas atmosphere from injection | pouring of electrolyte solution to sealing of a container.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these.

(Production of storage case)
A storage case as shown in FIG. 2 was manufactured using a stainless steel partition 2 having a length of 120 mm, a width of 160 mm, and a thickness of 2 mm (both ends are 10 mm), a stainless steel spacer 5 having a thickness of 16 mm, and a bolt 4. .

(Production of electric double layer capacitor cell)
A positive electrode body, a negative electrode body, and a separator made of an aramid fiber and a PET fiber are bonded to a polarizable electrode made of a mixture of activated carbon, carbon black, PTFE, and the like. A total of 36 sheets were laminated so that each could be connected to an electrode terminal, and a square laminate (thickness 16 mm) having a side of 100 mm was obtained. Next, the lead part of the positive electrode body and the lead part of the negative electrode body are respectively bonded to the electrode terminals by welding to produce a laminate as shown in FIG. 4, and then this is heated at 200 ° C. using a vacuum heating dryer. It was dried under reduced pressure for 18 hours.
In addition, a square flat container having a side of 150 mm and having an aluminum foil whose surface was covered with a film containing polypropylene as a base material was dried under reduced pressure at 50 ° C. for 15 hours using a vacuum dryer. This flat container had an opening on one side.

  After the laminate and the flat container were cooled to room temperature under a nitrogen atmosphere, the laminate was inserted into the container through the opening. Next, 160 ml of an electrolytic solution in which a quaternary ammonium salt or the like was dissolved in a propylene carbonate solvent was poured into the container. After the injection of the electrolytic solution was completed, the inside of the container was decompressed with a vacuum pump for 30 minutes, and the laminate was decompressed. The flat container into which the laminate was inserted was placed in the storage case during the decompression process. During this period, the electrode terminal was energized to perform electrolytic purification. Thereafter, the opening of the container was heated and pressurized from the outside to seal the container to obtain an electric double layer capacitor cell. A total of three such electric double layer capacitor cells were manufactured.

(Performance investigation of electric double layer capacitor cell)
For the three electric double layer capacitor cells manufactured as described above and arranged in a storage case as shown in FIG. 2, charge / discharge of 0V-2.7V at room temperature (25 ° C.) (30 minutes after 1 hour of charge start) The discharge was repeated 10 times, and the capacitance, internal resistance (ESR, normalized ESR), and charge / discharge efficiency were measured. The results (results immediately after production) are shown in Table 1.
Next, the electric double layer capacitor was charged at 2.7 V in an environment of 70 ° C., and this state was maintained for 500 hours (accelerated deterioration). Thereafter, charging / discharging (discharged to 0V over 30 minutes after 1 hour of charging) at 0V-2.7V at room temperature (25 ° C.) was repeated 10 times, and then capacitance, internal resistance (ESR, normalization) ESR) and charge / discharge efficiency were measured. The results (results after accelerated deterioration) are shown in Table 2.

[Comparative Example 1]
Three electric double layer capacitor cells manufactured in the same manner as in Example 1 were directly stacked without using a partition so that the laminate surfaces face each other, and stainless steel plates (thickness 10 mm) were placed at both ends. Furthermore, an electric double layer capacitor module having a configuration capable of applying a pressure of 0.2 MPa from the outside by a spring was manufactured.
Next, the capacitance, internal resistance (ESR, normalized ESR), and charge / discharge efficiency immediately after manufacture and after accelerated deterioration were measured in the same manner as in Example 1. The results are shown in Tables 3 and 4.

(Production of storage case and electric double layer capacitor cell)
In the production of the storage case of Example 1, a storage case was manufactured using the same partitions, bolts, and spacers as in Example 1 except that the configuration was such that ten electric double layer capacitor cells could be installed. Further, a total of 10 electric double layer capacitor cells were produced in the same manner as in Example 1.

(Heat dissipation investigation of electric double layer capacitor cells)
About 10 electric double layer capacitor cells manufactured as described above and arranged in the storage case, a thermocouple is installed at a position corresponding to the center of the laminated body surface, and 0 V to 2.7 V at room temperature (25 ° C.). The temperature after 100 times of rapid charge / discharge (30 seconds after the start of charging and discharging to 0 V over 30 seconds) was measured. As a result, the average temperature was 32 ° C. In addition, after the temperature of the electric double layer capacitor cell was lowered to 25 ° C., the same temperature measurement as described above was performed while applying air to the spacers at both ends and air cooling. As a result, the average temperature was 28 ° C.

[Comparative Example 2]
Ten electric double layer capacitor cells manufactured in the same manner as in Example 2 are directly stacked without using a partition so that the laminated body faces each other, and stainless steel plates (thickness 10 mm) are arranged at both ends. Furthermore, an electric double layer capacitor module having a configuration capable of applying a pressure of 0.2 MPa from the outside by a spring was manufactured.
Next, in the same manner as in Example 2, a heat dissipation investigation of the electric double layer capacitor cell was performed. As a result, the average temperature was 43 ° C.

  As described above, the electric double layer capacitor module of the embodiment of the present invention fixes a plurality of electric double layer capacitor cells one by one so as to have a constant width, so that the electric double layer of the comparative example Compared to the capacitor module, it was found that the variation in pressure applied to the electric double layer capacitor cell was small, and the performance degradation of the capacitance, internal resistance, and charge / discharge efficiency due to repeated charge / discharge could be greatly improved. Further, it was found that, when rapid charge / discharge is performed, the heat of the electric double layer capacitor cell can be easily released, so that the deterioration of the performance of the electric double layer capacitor cell due to heat can be improved.

The block diagram which shows an example of the electric double layer capacitor module of this invention The perspective view which shows an example of the storage case used for the electric double layer capacitor module of this invention The perspective view which shows the example of each component used for the storage case of FIG. The perspective view which shows an example of the partition in this invention The perspective view which shows an example of the laminated body of the electrical double layer capacitor cell in this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor cell 2 Partition 3 Storage case 4 Bolt 5 Spacer 6 Hollow part 7 Laminated body 8 Lead part of positive electrode body 9 Lead part of negative electrode body 10 Positive electrode terminal 11 Negative electrode terminal

Claims (4)

  A partition provided with a plurality of electric double layer capacitor cells having a structure in which an electrode sheet composed of a current collector and a polarizable electrode and separators are alternately laminated and impregnated with an electrolytic solution are fixed at a predetermined interval The electric double layer capacitor module is characterized in that the electric double layer capacitor module is arranged in a storage case having a space between each partition.   The electric double layer capacitor module according to claim 1, wherein the polarizable electrode includes activated carbon that expands by charging.   The electric double layer capacitor module according to claim 1, wherein the partition is made of metal.   The electric double layer capacitor module according to claim 1, wherein the partition has heat dissipation means.

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