JP2009065080A - Laminated electric double-layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric double-layer capacitor capable of preventing occurrence of internal ground leakage by preventing leakage of an electrolyte to the outside of a unit. <P>SOLUTION: Between a collector electrode plate 7 having a secondary inlet/outlet hole 7a formed thereon, and an end plate 9 having a primary inlet/outlet hole 9a formed thereon, a space 30 is formed by arranging a seal member 12 sealing the inside, and a liquid absorbing member 11 capable of transmitting gas into the space 30 and of absorbing liquid is arranged. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer electric double layer capacitor.

  The flat plate type capacitor unit has a structure in which the internal resistance of the unit is reduced by applying a large pressing force to the electrode surface to reduce the contact resistance.

  As a specific method for applying the pressure, a method is adopted in which end plates such as aluminum are disposed on both surfaces of the laminate and tightened with bolts or the like. If the strength of the end plate is large and the tightening force is increased, the internal resistance of the unit is reduced, but the weight is increased and the energy density is lowered. Therefore, as a method of reducing the internal resistance while using a lightweight end plate, the capacitor unit is placed in an aluminum laminated bag having a high gas barrier property, and the inside is completely sealed in a state where the inside is decompressed (see, for example, FIG. 2). ).

  As shown in FIG. 2, the multilayer electric double layer capacitor 100 includes a plurality of cells 104 including separators 101 through which ions can permeate and activated carbon electrodes 102 and 103 disposed on both sides of the separators 101, respectively. A polarizing substrate (aluminum foil) 105 is disposed between the cells 104 to be laminated. The activated carbon electrodes 102 and 103 are impregnated with an electrolytic solution. A packing 106 is disposed on the outer periphery of the cell 104 so that the liquid does not leak. The packing 106 also has a function of insulating between the stacked cells 104.

  Here, the capacitor 100 is connected to both ends of a module formed by stacking a cell 104 having a required withstand voltage (single cell withstand voltage of about 2.5 V) 104, a packing 106, and a polarization base material 105 via collector electrodes 107 and 108. Plates 109 and 110 are respectively arranged. Spacers 111 extending in the stacking direction are inserted into the packing 106, and both ends of the spacer 111 are fastened to end plates 109 and 110 by bolts 112, respectively. Further, a capacitor unit (hereinafter referred to as a unit) 120 that is fastened with a bolt 112 is disposed in a package 113 made of an aluminum laminate film, and the package 113 is sealed in a state where the inside is decompressed. The sealed structure of the multilayer electric double layer capacitor 100 is maintained.

  By sealing in a reduced pressure state as described above, atmospheric pressure is directly applied to the electrode surface in an environment under atmospheric pressure, so that the internal resistance can be reduced without requiring an end plate having a large strength and mass.

JP 2002-75806 A

  In the above-described multilayer electric double layer capacitor 100, the degassing holes 105a, 107a, 109a are formed in the polarization base material 105, the collector electrode plate 107, and the end plate 109 so that the internal gas can escape when the unit 120 is decompressed. Are provided. When the package 113 is sealed under reduced pressure, the gas in the unit is released to the outside through these holes 105a, 107a, and 109a so that the inside is in a vacuum state.

  When this decompression sealing is performed or when the unit is used for a long period of time, the electrolyte contained in the activated carbon electrodes 102 and 103 is discharged to the outside of the unit 120 through the vent holes 105a, 107a, and 109a. There is a possibility of leakage. The leaked electrolytic solution spreads between the unit 120 and the package 113 and the entire unit 120 is wrapped with the electrolytic solution. In such a state, a high voltage applied to the unit 120 directly touches the electrolytic solution, causing an internal leakage and causing gas generation or heat generation due to decomposition of the electrolytic solution.

  Therefore, the present invention has been proposed in view of the above-described problems, and an object of the present invention is to provide an electric double layer capacitor that prevents leakage of an electrolytic solution to the outside and suppresses internal leakage.

  The multilayer electric double layer capacitor according to the first invention that solves the above-described problem includes a separator and a cell composed of two polarizable electrodes facing each other through the separator, and a packing disposed on the outer periphery of the cell. A secondary electrode formed on the current collector plate by laminating via a polarizing substrate, sandwiched by an end plate from both sides via a current collector plate, and injected from a primary supply / discharge hole formed in the end plate. A multi-layer electric double layer capacitor in which the inside is impregnated through a supply / discharge hole, the outside is covered with a package, and the inside is sealed in a decompressed state, wherein the end plate is formed with the primary supply / discharge hole A seal member for sealing the inside is provided between the collector electrode plate in which the secondary supply / discharge hole is formed to provide a space, and gas can permeate and absorb liquid in the space. Characterized in that a liquid absorbing member.

  The multilayer electric double layer capacitor according to the second invention for solving the above-mentioned problems is the multilayer electric double layer capacitor according to the first invention, wherein the liquid absorbing member is made of an absorbent polymer. It is characterized by.

  A multilayer electric double layer capacitor according to a third invention that solves the above-described problem is a multilayer electric double layer capacitor according to the first or second invention, wherein the liquid absorbing member is the primary supply / discharge hole. It is characterized by being arranged opposite to.

  According to the multilayer electric double layer capacitor according to the first aspect of the present invention, the sealing member that seals the interior between the end plate having the primary supply / discharge holes and the collector plate having the secondary supply / discharge holes is provided. An electrolytic solution that leaks from the inside through the secondary supply / discharge hole by providing a liquid absorbing member that is arranged to provide a space and that allows gas to pass through the space and absorb the liquid. Can be absorbed by the liquid absorbing member to prevent leakage of the electrolytic solution. As a result, it is possible to prevent the occurrence of leakage current and prevent heat generation associated therewith. Further, when gas is released from the primary supply / discharge hole of the end plate, the internal gas passes through the liquid absorbing member before reaching the primary supply / discharge hole, so that the electrolyte does not mix with the gas. Therefore, even if the package is damaged, the electrolytic solution is not ejected therefrom. In addition, modification from the conventional multilayer electric double layer capacitor is easy, and the increase in volume is small. As a result, a decrease in volume energy density can be suppressed.

  According to the multilayer electric double layer capacitor according to the second aspect of the invention, the liquid absorbing member is made of an absorptive polymer, so that the absorptive polymer itself has a good liquid absorptivity, and the internal electrolyte solution Leakage to the package side can be prevented more reliably.

  According to the multilayer electric double layer capacitor according to the third invention, in addition to the same operational effects as the multilayer electric double layer capacitor according to the first and second inventions described above, the liquid absorbing member has an end. By being arranged opposite to the primary supply / discharge hole formed in the plate, the liquid absorbing member is positioned in the leakage path to the inner electrolyte solution package body side, and the inner electrolyte solution to the package body side is located. Leakage can be prevented more reliably.

  Hereinafter, a multilayer electric double layer capacitor according to the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of a multilayer electric double layer capacitor according to the best embodiment of the present invention.

  As shown in FIG. 1, a multilayer electric double layer capacitor 50 according to the best embodiment of the present invention includes a separator 1 that can transmit ions and two activated carbon electrodes 2 disposed opposite to each other with the separator 1 interposed therebetween. 3 cells 4 and packings 6 arranged on the outer periphery of the cells 4 are laminated via a polarizing substrate (aluminum foil) 5. The packing 6 has a function of preventing leakage of an electrolyte solution impregnated in the interior, which will be described later, to the outside and insulating between the stacked cells 4.

  The capacitor 50 described above is connected to the required voltage endurance cell (single cell withstand voltage of about 2.5 V) 4, the packing 6, and the polarization base material 5 from both sides of the module through the collector plates 7 and 8. It is sandwiched between the plates 9 and 10.

  Spacers 13 extending in the stacking direction are inserted into the packing 6, and both ends of the spacer 13 are fastened to the end plates 9 and 10 by bolts 14, respectively. Further, a primary supply / discharge hole 9 a is formed in the center of the end plate 9, and the electrolytic solution supplied to the primary supply / discharge hole 9 a is a secondary supply formed near the edge of the collector electrode plate 7. The cells 4, packing 6, polarization substrate 5, collector electrode plates 7 and 8, and end plates 9 and 10 pass through the discharge holes 7 a and the tertiary supply / discharge holes 5 a formed in the vicinity of the edge of the polarization substrate 5. It is impregnated in a capacitor unit (hereinafter referred to as a unit) 20 that is fastened by a bolt 14. In addition, as said electrolyte solution, a non-aqueous electrolyte solution etc. are mentioned, for example.

  The unit 20 is disposed in a package 15 made of an aluminum laminate film. When the inside is reduced and sealed, the unit 20 passes through the tertiary supply / discharge hole 5a, the secondary supply / discharge hole 7a, and the primary supply / discharge hole 9a. The gas inside 20 escapes to the outside and the inside is held in a vacuum state, and the hermetic structure of the multilayer electric double layer capacitor 50 is maintained.

  However, a seal member (packing) 12 that seals the inside is disposed between one collector electrode plate 7 and one end plate 9 described above, and a space 30 is provided at that location. The liquid absorbing member 11 that allows gas to pass through the space 30 and absorbs the electrolytic solution (liquid) is disposed. However, the liquid absorbing member 11 is disposed at a position facing the primary supply / discharge hole 9 a formed in the end plate 9. The seal member 12 is formed of a frame made of rubber, which is the same material as the packing 6, and is disposed on the outer periphery of the liquid absorbing member 11.

  Examples of the liquid absorbing member 11 described above include those in which an absorbent polymer is formed in a sheet shape. By setting it as the liquid absorption member 11 of such a material, the liquid absorption member 11 itself can have the corrosion resistance with respect to the said electrolyte solution, and the absorptivity of the said electrolyte solution. Therefore, leakage of the internal electrolyte solution to the package 15 side can be prevented more reliably.

  Therefore, according to the multilayer electric double layer capacitor according to the best embodiment of the present invention, the end plate 9 in which the primary supply / discharge holes 9a are formed and the collector electrode plate 7 in which the secondary supply / discharge holes 7a are formed. A space 30 is provided by disposing a sealing member 12 for sealing the inside therebetween, and a liquid absorbing member 11 that can transmit gas and absorb liquid in the space 30 is provided. The electrolytic solution leaking through the secondary supply / discharge hole 7a can be absorbed by the liquid absorbing member 11, and leakage of the electrolytic solution can be prevented. As a result, it is possible to prevent the occurrence of leakage current and prevent heat generation associated therewith. Further, when the gas is released from the primary supply / discharge hole 9a of the end plate 9, the internal gas passes through the liquid absorbing member 11 before reaching the primary supply / discharge hole 9a, so that the electrolyte is mixed with the gas. There is no. Therefore, even if the package 15 is damaged, the electrolytic solution is not ejected therefrom. In addition, modification from the conventional multilayer electric double layer capacitor is easy, and the increase in volume is small. As a result, a decrease in volume energy density can be suppressed.

  Since the liquid absorbing member 11 is arranged to face the primary supply / discharge hole 9a formed in the end plate 9, the liquid absorbing member 11 is positioned in the leakage path of the internal electrolyte solution to the package 15 side. Thus, leakage of the internal electrolyte solution to the package 15 side can be more reliably prevented.

  Below, the electric double layer capacitor according to the best mode of the present invention described above will be specifically described based on examples.

  The multilayer electric double layer capacitor according to the first embodiment of the present invention will be specifically described below. Note that the multilayer electric double layer capacitor according to the first example of the present invention has the same configuration as the multilayer electric double layer capacitor according to the above-described best embodiment, and a description thereof will be omitted.

  In the multilayer electric double layer capacitor according to the first embodiment of the present invention, Neuparon (registered trademark) DB type manufactured by Sekisui Jushi Corporation is used as the liquid absorbing member 11.

The above-mentioned Neupalon DB type is a sheet of a water-absorbing polymer and has a very large water absorption performance of 5 L / m ² . Although it is a moisture absorbing sheet originally intended to maintain the freshness of fruits and vegetables, an equivalent absorbing performance was confirmed even with the electrolyte solvent propylene carbonate used in the capacitor.

  Therefore, according to the multilayer electric double layer capacitor according to the first embodiment of the present invention, the space between the collector plate 7 provided with the secondary supply / discharge holes 7a and the end plate 9 provided with the primary supply / discharge holes 9a. By disposing the Neupalon DB type, which is the liquid absorbing member (water-absorbing polymer sheet) 11, the liquid absorbing member 11 can reliably absorb the electrolyte leaking from the unit. As a result, it is possible to prevent the electrolyte solution from leaking to the side of the package 15 made of an aluminum laminate film that wraps the outside, to prevent the occurrence of leakage current, and to prevent heat generation associated therewith.

  The electric double layer capacitor according to the second embodiment of the present invention will be specifically described below. Note that the multilayer electric double layer capacitor according to the second example of the present invention has the same configuration as the multilayer electric double layer capacitor according to the above-described best embodiment, and a description thereof will be omitted.

  In the multilayer electric double layer capacitor according to the second embodiment of the present invention, a Neuparon (registered trademark) BO type manufactured by Sekisui Plastics Co., Ltd. is used as the liquid absorbing member 11.

  The above-mentioned Neupalon BO type is composed of a water-absorbing polymer and activated carbon, and has gas adsorption performance. Although the water absorption performance is inferior to the above-mentioned Neupalon DB type, the gas generated when the capacitor is used can be adsorbed to the liquid absorbing member 11, so that the decompression force in the unit can be maintained for a long time.

  Therefore, according to the multilayer electric double layer capacitor according to the second embodiment of the present invention, the Neuparon BO type to which activated carbon is added as the liquid absorbing member 11 is used in the first embodiment of the present invention. In addition to the same effects as the multilayer electric double layer capacitor, the gas generated when the capacitor is used can be adsorbed, and the decompression effect in the unit is maintained over a long period of time, thereby slowing down the performance degradation rate of the capacitor. As a result, the lifetime can be extended.

  The present invention can be used for a multilayer electric double layer capacitor.

1 is a cross-sectional view showing a configuration of a multilayer electric double layer capacitor according to the best embodiment of the present invention. It is sectional drawing which shows the structure of the conventional multilayer electric double layer capacitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Separator 2, 3 Activated carbon electrode 4 Cell 5 Polarization base material 6 Packing 7, 8 Current collecting plate 9, 10 End plate 11 Liquid absorption member 12 Seal member 13 Spacer 14 Bolt 15 Packaging body 20 Capacitor unit 30 Space 50 Multilayer electric two Multilayer capacitor

Claims (3)

A cell comprising a separator and two polarizable electrodes facing each other with the separator and a packing disposed on the outer periphery of the cell being laminated via a polarizing substrate, and from both sides via a collector electrode plate The electrolytic solution injected from the primary supply / discharge hole formed in the end plate is impregnated inside through the secondary supply / discharge hole formed in the collector electrode plate, and the outside is covered with a package, and the inside A multilayer electric double layer capacitor that is hermetically sealed in a decompressed state,
A seal member for sealing the inside is provided between the end plate in which the primary supply / discharge holes are formed and the collector plate in which the secondary supply / discharge holes are formed, and a space is allowed to pass through the space. A multilayer electric double layer capacitor having a liquid absorbing member capable of absorbing liquid. The multilayer electric double layer capacitor according to claim 1,
2. The multilayer electric double layer capacitor according to claim 1, wherein the liquid absorbing member is made of an absorbent polymer. A multilayer electric double layer capacitor according to claim 1 or 2, wherein
The multilayer electric double layer capacitor, wherein the liquid absorbing member is disposed to face the primary supply / discharge hole.

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