JP2008028296A - Laminated electric double layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated electric double layer capacitor having a structure for preventing leakage of electrolyte from inside of a capacitor unit to the outside. <P>SOLUTION: A laminated electric double layer capacitor 20 comprises a multi-layer laminated member 1 with a plurality of polarizing electrodes 9 laminated via a separator 7, a first collector electrode plate 2 and a second collector electrode plate 3 provided on both sides of the multi-layer laminated member 1, and a first end plate 4 and a second end plate 5 for sandwiching the collector electrode plates 2, 3. An aluminum laminated film 30 covers and seals the laminated electric double layer capacitor. A primary degassing hole 14 is provided in the first collector electrode plate 2, a secondary degassing hole 15 is provided in the first end plate 4, and an electrolyte absorbing member 18 for absorbing electrolyte is disposed between the first collector electrode plate 2 and the first end plate 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multilayer electric double layer capacitor, and more particularly to a multilayer electric double layer capacitor that is sealed with an external seal wrapping material and reduces the internal resistance by reducing the internal pressure.

  Conventionally, a flat-plate multilayer capacitor unit (hereinafter referred to as a capacitor unit) composed of multilayer electric double layer capacitors reduces the internal resistance of the capacitor unit by applying a large pressure to the electrode surface to reduce the contact resistance. It has a structure. That is, an end plate made of aluminum or the like is arranged on both surfaces of a multi-layered body, and the two end plates are fastened with bolts or the like to tighten the laminated body, thereby applying pressure to the electrode surface (for example, a patent Reference 1).

JP 2003-217986 A

  However, if the strength of the end plate is increased in order to improve the tightening force by the end plate, the internal resistance of the capacitor unit is reduced, but there is a possibility that the energy density is lowered such as an increase in weight.

  Therefore, in order to reduce the internal resistance while using a lightweight end plate, for example, a configuration as shown in FIG. 2 can be considered. That is, the capacitor unit 120 is wrapped and sealed with an aluminum laminate film 130 having a high gas barrier property. By adopting such a configuration, the internal resistance can be reduced by extracting the internal gas and reducing the pressure.

  The capacitor unit 120 has a configuration in which the multi-layered body 101 is sandwiched between two collector electrode plates 102 and 103 and further sandwiched between two end plates 104 and 105. The multi-layered body 101 has a polarization in which activated carbon electrodes 106 are bonded to both surfaces of a polarization base material (for example, aluminum foil) between activated carbon electrodes 106 bonded to opposite surfaces of the collector electrode plates 102 and 103, respectively. The electrode 109 is laminated through the separator 107. The activated carbon electrode 106 is impregnated with an electrolytic solution.

  An inter-cell packing 110 is interposed along the outer edge between the adjacent polarized base materials 108 or between the adjacent polarized base materials 108 and the collector electrode plates 102 and 103. The inter-cell packing 110 prevents leakage of the electrolyte solution to the outside of the capacitor unit 120, and also has an insulating function between the adjacent polarization base materials 108 or between the polarization base material 108 and the current collector plates 102 and 103. I have. A spacer 111 extending in the stacking direction of the polarization electrodes 109 is inserted into the inter-cell packing 110.

  Bolts 112 are fastened to both ends of the spacer 111 from end plates 104 and 105, respectively. Thus, the collector plates 102 and 103 are fastened by the end plates 104 and 105 to maintain a sealed structure and apply pressure to the electrode surface.

  Further, the capacitor unit 120 is provided with a gas vent hole 113 that penetrates the collector electrode plate 102 and the end plate 104 and communicates the inside and outside of the capacitor unit 120. The gas vent hole 113 is provided to discharge the gas inside the capacitor unit 120 sealed by the aluminum laminate film 130 to the outside of the capacitor unit 120. The polarization base material 108 is provided with a gas vent hole 108a.

  That is, when the pressure reduction sealing of the capacitor unit 120 is performed with the aluminum laminate film 130, the capacitor unit 120 is wrapped with the aluminum laminate film 130, and the gas in the capacitor unit 120 is discharged to the outside through the gas vent hole 113. Is in a vacuum state. Thus, the inside of the capacitor unit 120 is completely sealed with the pressure reduced.

  With the above-described configuration, the capacitor unit 120 shown in FIG. 2 can reduce the internal resistance even when the end plates 104 and 105 are lightweight. By sealing the capacitor unit 120 in a reduced pressure state in this way, atmospheric pressure is directly applied to the electrode surface in an environment under atmospheric pressure, and the internal resistance can be reduced without using an end plate having high strength and weight.

  However, in the structure of the capacitor unit 120 shown in FIG. 2 described above, the electrolytic solution impregnated in the activated carbon electrode 106 passes through the gas vent hole 113 when the reduced pressure seal is performed or when used for a long period of time. There is a possibility that a problem of leakage to the outside of 120 occurs.

  When the electrolyte solution leaks from the gas vent hole 113, the leaked electrolyte solution may spread into the space between the capacitor unit 120 and the aluminum laminate film 130, and the entire capacitor unit 120 may be encased in the electrolyte solution. is there. In such a state, the high voltage applied to the capacitor unit 120 directly touches the leaked electrolyte, causing internal leakage, causing gas generation due to decomposition of the electrolyte, heat generation, fire, etc. There is a possibility.

  Accordingly, an object of the present invention is to provide a multilayer electric double layer capacitor having a structure that prevents the electrolytic solution from leaking out of the capacitor unit.

  A multilayer electric double layer capacitor according to claim 1 of the present invention for solving the above-described problem is provided with a multi-layer body in which a plurality of polarization electrodes are stacked via separators, and on both surfaces of the multi-layer body. In the multilayer electric double layer capacitor comprising the first and second current collector plates and the first and second end plates sandwiching the current collector plates, and covered and sealed with an external seal packaging material, The adjacent first collector plate and the first end plate have a primary vent hole and a secondary vent hole, respectively, and between the first collector plate and the first end plate. Further, an electrolytic solution absorber that absorbs the electrolytic solution is interposed.

  A multilayer electric double layer capacitor according to a second aspect of the present invention is the multilayer electric double layer capacitor according to the first aspect, wherein the electrolyte absorber transmits gas and faces at least the secondary gas vent hole. It is characterized by being interposed at a position where

  According to the multilayer electric double layer capacitor according to the above-described embodiment, the electrolytic solution absorber that absorbs the electrolytic solution and transmits the gas is interposed between the first collector plate and the first end plate. By providing, when decompressing the inside of the capacitor unit, gas can be discharged from the primary gas vent hole and the secondary gas vent hole.

  Further, when the electrolyte leaks from the primary gas vent hole, the leaked electrolyte solution is absorbed by the electrolyte absorber, so there is no possibility of leaking from the secondary gas vent hole to the outside of the capacitor unit. Therefore, it is possible to prevent leakage of the electrolyte into the space between the capacitor unit and the outer seal packaging material, thereby preventing leakage current generation of the capacitor unit, and accompanying this, gas generation and heat generation due to decomposition of the electrolyte , And the risk of fire can be avoided.

  Furthermore, if the electrolyte absorber is provided at a position opposite to the secondary vent hole, even if the electrolyte leaks out of the primary vent hole, it is ensured before reaching the secondary vent hole. Since it is absorbed by the electrolytic solution absorber, the possibility of leakage from the secondary vent hole is further reduced.

  Embodiments of the present invention will be described below. In the present embodiment, a multi-layered body in which a plurality of polarization electrodes are stacked via separators, first and second current collector plates provided on both surfaces of the multi-layered body, and first and second sandwiching the current collector plates It is applied to a multilayer electric double layer capacitor that includes a second end plate and is sealed with an aluminum laminate film as an outer seal wrapping material, and prevents leakage of the electrolytic solution to the outside of the capacitor unit.

  Specifically, the first collector plate and the first end plate adjacent to each other of the multilayer electric double layer capacitor are provided with a primary vent hole and a secondary vent hole, respectively. An electrolytic solution absorber that absorbs the electrolytic solution and permeates the gas is interposed between the end plate.

  With the above-described configuration, even when the electrolytic solution oozes out from the activated carbon electrode when the capacitor unit is depressurized or when the capacitor unit is used for a long period of time, it leaks from the primary vent hole. The electrolyte is absorbed by the electrolyte absorber and does not leak out from the secondary gas vent hole. Therefore, it is possible to prevent gas generation, heat generation, fire, and the like associated with the decomposition of the electrolytic solution due to internal leakage.

  If a paper wiper or a non-woven wiper is used as the electrolyte absorber, the leakage current of the unit is prevented by preventing leakage of the electrolyte into the unit film, thereby preventing the risk of heat generation and ignition. Can do.

  In addition to the above-described effects, the gas generated when the capacitor is used can be adsorbed by using activated carbon powder made of polytetrafluoroethylene (PTFE) or the like as a binder binder as an electrolyte absorber. it can. Therefore, the pressure reducing effect in the capacitor unit can be easily maintained, and the speed of deterioration of the capacitor performance can be delayed, so that the life of the capacitor can be extended.

  An embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a cross-sectional view schematically showing a multilayer electric double layer capacitor in this example. In addition, each structural member 1-12 shown in FIG. 1 respond | corresponds to each structural member 101-112 shown in FIG. Hereinafter, description of parts similar to those in the configuration illustrated in FIG. 2 will be omitted, and description will be made focusing on differences in configuration.

  As shown in FIG. 1, the capacitor unit 20 is covered and sealed with an aluminum laminate film 30 that is an external seal packaging material having a high gas barrier property. The capacitor unit 20 has a configuration in which both side surfaces of the multi-layered body 1 are sandwiched between the first and second collector electrode plates 2 and 3 and the first and second end plates 4 and 5 are disposed on the outer sides thereof. ing.

  An absorbent layer packing 16 is interposed between the collector electrode plate 2 and the end plate 4 along these peripheral edges. A space 17 is formed between the collector electrode plate 2 and the end plate 4 by the absorbent layer packing 16, and Crecia Kim Towel White (trade name, material: material used as a paper wiper as an electrolyte absorber 18 in the space 17. Pulp 100%). Kim Towel White is suitable as an electrolytic solution absorber because it is inexpensive and has excellent water absorption.

  Furthermore, a primary gas vent hole 14 and a secondary gas vent hole 15 are formed in the collector electrode plate 2 and the end plate 4, respectively. The primary gas vent hole 14 is provided in the vicinity of the inter-cell packing 10, that is, on the space side between the activated carbon electrode 6 and the inter-cell packing 10, and communicates the inside and outside of the multi-layered product 1. The secondary gas vent hole 15 is provided at a position facing the electrolytic solution absorber 18, specifically, near the center of the end plate 4.

  According to the multilayer electric double layer capacitor according to this embodiment described above, the gas vent holes 14 and 15 are formed in the collector electrode plate 2 and the end plate 4, respectively, and between the collector electrode plate 2 and the end plate 4. Since the electrolytic solution absorber 18 is interposed in the electrolyte solution, even if the electrolytic solution leaks into the space 17 from the primary gas vent hole 14, the leaked electrolytic solution is absorbed by the electrolytic solution absorber 18. No leakage from the next vent hole 15 to the outside.

  Therefore, there is no possibility of causing internal leakage and generating gas, heat generation, fire, etc. due to decomposition of the electrolyte. The electrolytic solution absorber 18 is made of a material that absorbs liquid and transmits gas so that the work can be smoothly performed when the gas in the aluminum laminate film 30 is extracted.

  Next, a second embodiment of the present invention will be described. In this example, as the electrolytic solution absorber 18 shown in FIG. 1 in Example 1 described above, a wipeall X80 (trade name, material: pulp + polypropylene (PP) non-woven fabric) made of Crescia, which is a non-woven wiper, is used. It is what is used. The other configuration is the same as the configuration shown in FIG. 1 of the first embodiment, and the same reference numerals are used for similar configurations, and the description is omitted.

  Wipeall X80 has excellent absorbability with respect to the electrolytic solution and also has excellent strength after absorbing the electrolytic solution. In addition, lint and scuffing are less likely to occur, and there is no possibility of affecting the capacitor characteristics when used as the electrolyte absorber 18.

  Therefore, according to the multilayer electric double layer capacitor in accordance with the present embodiment, by using the wipe all X80 as the electrolyte absorber 18, the electrolyte leaked into the space 17 from the primary vent hole 14 can be easily removed by the wipe all X80. Therefore, the possibility that the electrolyte leaks from the secondary gas vent hole 15 between the capacitor unit 20 and the aluminum laminate film 30 can be further reduced.

  A third embodiment of the present invention will be described. In this example, as the electrolyte solution absorber 18 shown in FIG. 1 in Example 1 described above, a material obtained by forming a sheet of activated carbon powder using PTFE or the like as a bindery (hereinafter referred to as an activated carbon sheet) is used. The other configurations are the same as those shown in FIG. 1 of the first embodiment, and the same symbols are used for similar configurations, and the description thereof is omitted.

  The activated carbon sheet is made of activated carbon in the same manner as the electrode used for the capacitor component, and has a gas adsorption function. Therefore, it becomes possible to adsorb the gas generated when the capacitor is used by the activated carbon sheet, absorb the electrolyte leaked from the primary gas vent hole 14 to the space 17, and maintain the decompression force in the capacitor unit 20 for a long period of time. Can do.

  According to the multilayer electric double layer capacitor in accordance with the present embodiment, in addition to the operational effects in the first embodiment or the second embodiment described above, the pressure reducing effect in the capacitor unit 20 can be maintained, and the performance degradation rate can be delayed. Therefore, the lifetime can be extended.

  In addition, the electrolyte solution absorber 18 shown in Examples 1 to 3 is not limited to the above-described material, and it penetrates gas and absorbs liquid, and is eroded by the electrolyte solution to cause corrosion and chemical reaction. As long as there is no substance. The present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

  That is, the present invention can be used for a multilayer electric double layer capacitor. Specifically, the present invention is useful for a multilayer electric double layer capacitor that is hermetically sealed with an external seal wrapping material and reduces the internal resistance by reducing the internal resistance.

It is sectional drawing which shows typically the multilayer type electric double layer capacitor which concerns on Example 1 of this invention. It is sectional drawing which shows typically the prior art example of a multilayer type electric double layer capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multilaminate 2 1st current collector plate 3 2nd current collector plate 4 1st end plate 5 2nd end plate 9 Polarizing electrode 10 Packing between cells 14 Primary gas vent hole 15 Secondary gas vent hole 16 Absorption Layer packing 17 Space 18 Electrolyte absorber 20 Multilayer double layer capacitor unit 30 Aluminum laminate film

Claims (2)

  A multi-layered body in which a plurality of polarization electrodes are stacked via separators, first and second collector plates provided on both surfaces of the multi-layered body, and first and second sandwiching the collector electrode plates In a multilayer electric double layer capacitor that includes an end plate and is covered and sealed with an external seal packaging material, the first collector electrode plate and the first end plate that are adjacent to each other have primary gas vent holes and A multilayer electric battery having a secondary vent hole and an electrolyte solution absorber for absorbing an electrolyte solution interposed between the first collector electrode plate and the first end plate Multilayer capacitor.   2. The multilayer electric double layer capacitor according to claim 1, wherein the electrolytic solution absorber is interposed at a position that allows gas to pass therethrough and at least faces the secondary gas vent hole.

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