JP2005209640A - Battery case and battery, and electric double layer capacitor case and electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily connect to an external electric circuit board without leaking the electrolyte performance due to long-term use and degrading the battery performance or damaging the external electric circuit board due to the leaked electrolyte. To provide a battery case and battery excellent in mass productivity, and an electric double layer capacitor case and electric double layer capacitor.
A battery case and an electric double layer capacitor case have a base body 1 in which a plurality of ceramic green sheets 1-B are stacked and fired, and a rectangular parallelepiped recess 1a is formed at the center of the upper surface. The concave portion 1a has a stepped portion 1-C formed on the inner side surface as the inner dimension increases stepwise toward the upper side of the base 1, and the stepped portion 1-C is depressed. The ceramic layer 4 is formed over the entire circumference at the corner.
[Selection] Figure 1

Description

  TECHNICAL FIELD The present invention relates to a battery case and a battery used for a rechargeable battery and the like, and an electric double layer capacitor case and an electric double layer capacitor, and more specifically, a thin battery case used for a small electronic device such as a mobile phone and the like. The present invention relates to a case for an electric double layer capacitor and an electric double layer capacitor used as a backup power source for batteries and semiconductor memories, a standby power source for small electronic devices, and the like.

  In recent years, portable devices typified by mobile phones, portable computers, camera-integrated video tape recorders, etc. have been remarkably developed, and further miniaturization and weight reduction have been demanded. In addition, the demand for batteries as power sources for these portable devices continues to increase, and research on reducing the size and weight by increasing the energy density of the batteries is actively conducted. In particular, the lithium battery is a battery using lithium with a small atomic weight and a large ionization energy, so that it is possible to obtain a high energy density, to achieve a reduction in size and weight, and to be a battery that can be recharged more actively. It has been researched and has now been used for a wide range of applications including power supplies for portable devices.

  Batteries can be broadly divided into cylindrical and square types. The structure is that the positive and negative electrodes are housed in a metal battery case through a separator made of an insulating sheet, and an electrolyte is injected there. It is a sealed structure.

As a positive electrode of a lithium battery, for example, a metal oxide used as a positive electrode active material and a conductive material added thereto is generally used. For example, lithium cobaltate (LiCoO ₂ ) or lithium manganate (LiMn ₂ O ₄ ) is used as the positive electrode active material, and acetylene black (AB) or graphite is used as the conductive material. For the negative electrode of the battery, a lithium-titanium composite oxide such as lithium titanate (Li ₄ Ti ₅ O ₁₂ ) or an active material such as graphite or amorphous carbon solidified with a resin is used.

In the lithium battery, the charge / discharge voltage of the positive electrode active material made of LiCoO ₂ or LiMn ₂ O ₄ is about 4V, while the charge / discharge voltage of the negative electrode active material made of a carbon material or the like is around 0V. For this reason, a high discharge voltage of about 3.5 V is achieved by combining these positive electrode active material, negative electrode active material, and electrolytic solution.

  For the positive electrode of the battery, the conductive material is added to the active material, and a binder such as polytetrafluoroethylene or polyvinylidene fluoride is added and mixed to form a slurry, which is formed into a sheet using a well-known doctor blade method. The sheet is formed and then cut into, for example, a circular shape.

  Also, the negative electrode is added to the above active material, as in the positive electrode, a binder such as polytetrafluoroethylene or polyvinylidene fluoride, mixed to form a slurry, and this is formed into a sheet using a known doctor blade method, Next, this sheet is cut into a circular shape, for example.

  Then, the positive electrode and the negative electrode thus prepared are accommodated in a battery case via a separator made of a polyolefin fiber nonwoven fabric or a polyolefin microporous film having a heat resistant temperature of about 150 ° C. A battery is obtained by injecting the liquid.

  In order to further reduce the size and density of the battery thus manufactured, a coin-type battery A shown in FIG. 5 has been developed.

  This conventional battery A is a separator in which a positive electrode can 11 made of, for example, stainless steel provided with a disk-shaped positive electrode 11b and a negative electrode can 12 made of, for example, stainless steel provided with a disk-shaped negative electrode 12b are impregnated with an electrolyte. The battery case structure is configured such that the periphery of the positive electrode can 11 and the periphery of the negative electrode can 12 are caulked together via a gasket 15 made of, for example, insulating polypropylene resin. ing. Charging / discharging in the positive electrode 11b and the negative electrode 12b is performed via an external connection terminal member attached to the positive electrode can 11 and the negative electrode can 12 (see, for example, Patent Documents 1 and 2 below).

  Also, in the electric double layer capacitor, in order to reduce the size and density of the electric double layer capacitor, the first electrode can having the shape shown in FIG. A coin-type electric double layer capacitor formed by crimping 11 and the second electrode can 12 has been developed.

The electric double layer capacitor includes a first electrode can 11 made of, for example, stainless steel provided with a disk-shaped first electrode 11b, and a second electrode can 12 made of, for example, stainless steel provided with a second electrode 12b. With the separator 14 containing the electrolytic solution sandwiched between the first electrode 11b and the second electrode 12b, the edge of the first electrode can 11 and the edge of the second electrode can 12 are gasketed. It is formed by caulking and joining through 15. Charging / discharging in the first electrode 11b and the second electrode 12b is performed via an external connection terminal member attached to the first electrode can 11 and the second electrode can 12 (for example, Patent Document 3 below) 4).
JP 2000-106195 A (page 6-12, FIG. 1) JP 2002-198019 A (page 3-4, FIG. 1) Japanese Patent Laid-Open No. 2002-50551 JP 2003-100569 A

  However, when the conventional battery A as shown in Patent Documents 1 and 2 is exposed to a temperature cycle (for example, −40 ° C. to 85 ° C.) having a temperature range of hundreds of degrees over a long period of time, for example, polypropylene Due to the difference in coefficient of thermal expansion between the gasket 15 made of resin, the positive electrode can 11 and the negative electrode can 12, a gap is generated at the joint portion of the battery case can which is caulked around the positive electrode can 11 and the negative electrode can 12 via the gasket 15. In some cases, the liquid may leak, which may deteriorate the battery performance of the battery A, or cause the copper (Cu) wiring on the external electric circuit board to corrode and break due to the leaked electrolyte. Alternatively, there has been a problem in that moisture enters the inside of the battery A from this gap and deteriorates the battery performance.

  Also, in the conventional electric double layer capacitor as shown in Patent Documents 3 and 4, as in the conventional battery, a temperature cycle test (for example, −40 ° C. to 85 ° C.) with a temperature range of hundreds of degrees over a long period of time. When the first electrode can 11 and the second electrode can 11 and the second electrode can 12 through the gasket 15 due to a difference in thermal expansion coefficient between the gasket 15 made of polypropylene resin, the first electrode can 11 and the second electrode can 12, for example. There may be a gap at the joint of the battery case that crimps the periphery of the second electrode can 12, causing the electrolyte to leak out, which may deteriorate the performance of the electric double layer capacitor or cause the electrolyte to leak. Problems such as Cu wiring on the external electric circuit board corroded and broken, or moisture enters the electric double layer capacitor through this gap and degrades the battery electric double layer capacitor performance. Had occurred.

  Accordingly, the present invention has been completed in view of the above-mentioned problems, and its purpose is to deteriorate the battery performance due to leakage of the electrolyte due to the formation of a gap in the joint portion of the battery case due to long-term use. The battery case and the battery, and the electric double layer capacitor case and the electricity can be easily connected to the external electric circuit board and have excellent mass productivity without being damaged by the leaked electrolyte. It is to provide a double layer capacitor.

  The battery case of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a recess is formed in the center of the upper surface, and a first conductor layer and a second conductor layer are formed independently on the lower surface. A first metallization layer formed on the bottom surface of the recess, a second metallization layer formed on the top surface of the step formed between the inner surface and the bottom surface of the recess, A first connection conductor that electrically connects one metallization layer and the first conductor layer, and a second connection conductor that electrically connects the second metallization layer and the second conductor layer; The concave portion has a stepped portion formed on the inner surface due to the stepwise increase in internal dimensions as it goes upward of the base, and the concave corner portion of the stepped portion is formed. A ceramic layer is formed over the entire circumference. The features.

  The battery of the present invention is in close contact with the battery case having the above-described configuration, a positive electrode plate connected to the first metallization layer, and an insulating sheet impregnated with an electrolyte on the upper surface of the positive electrode plate. And a negative electrode plate connected to the second metallized layer and a lid joined so as to cover the recess.

  The battery case of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a recess is formed in the center of the upper surface, and the first conductor layer and the second conductor layer are independent of each other on the lower surface. The first metallization layer formed on the bottom surface of the recess, the second metallization layer formed around the recess on the upper surface of the substrate, the first metallization layer, A first connection conductor that electrically connects the first conductor layer and a second connection conductor that electrically connects the second metallization layer and the second conductor layer; The concave portion has a stepped portion formed on the inner surface due to the stepwise increase in inner dimension toward the upper side of the base, and the ceramic layer is formed over the entire circumference at the concave corner portion of the stepped portion. Is formed

  The battery of the present invention is in close contact with the battery case having the above-described configuration, the positive electrode plate connected to the first metallization layer, and the upper surface of the positive electrode plate via an insulating sheet impregnated with an electrolyte. The negative electrode plate placed so as to cover the recess, and at least the lower main surface is made conductive, and the lid is connected to the negative electrode plate and the second metallization layer. It is characterized by comprising.

  The electric double layer capacitor case of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a recess is formed in the center of the upper surface, and the first conductor layer and the second conductor layer are independent of each other on the lower surface. And a second metallization layer formed on the upper surface of the step formed between the inner side surface and the bottom surface of the recess, and a base metal layer formed on the bottom surface of the recess. , A first connection conductor for electrically connecting the first metallized layer and the first conductor layer, and a second for electrically connecting the second metallized layer and the second conductor layer. A connecting conductor is provided, and the concave portion has a stepped portion formed on an inner surface due to a stepwise increase in inner dimension toward the upper side of the base, and the stepped portion is recessed. A ceramic layer is formed around the entire corner. Characterized in that it is.

  The electric double layer capacitor of the present invention includes an electric double layer capacitor case configured as described above, a first electrode connected to the first metallization layer, and an upper surface of the first electrode impregnated with an electrolyte. A second electrode connected to the second metallization layer and a lid joined so as to cover the recess. Features.

  The case for the electric double layer capacitor of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a recess is formed in the center of the upper surface, and the first conductor layer and the second conductor layer are formed on the lower surface. A base formed independently of each other, a first metallization layer formed on the bottom surface of the recess, a second metallization layer formed around the recess on the top surface of the base, and the first metallization A first connection conductor that electrically connects the layer and the first conductor layer, and a second connection conductor that electrically connects the second metallization layer and the second conductor layer. The concave portion has a stepped portion formed on the inner surface due to the stepwise increase in inner dimension toward the upper side of the base, and the entire circumference is formed in the concave corner portion of the stepped portion. A ceramic layer is formed over And wherein the door.

  The electric double layer capacitor of the present invention includes an electric double layer capacitor case configured as described above, a first electrode connected to the first metallization layer, and an upper surface of the first electrode impregnated with an electrolyte. The second electrode placed so as to be in close contact via the separator is joined so as to cover the recess, and at least the lower main surface is made conductive, and the second electrode and the second electrode And a lid connected to the metallized layer.

  The battery case of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a recess is formed in the center of the upper surface, and a first conductor layer and a second conductor layer are formed independently on the lower surface. A first metallization layer formed on the bottom surface of the recess, a second metallization layer formed on the top surface of the step formed between the inner surface and the bottom surface of the recess, and the first metallization A first connection conductor that electrically connects the layer and the first conductor layer, and a second connection conductor that electrically connects the second metallization layer and the second conductor layer. The electrolytic solution is accommodated by a base made of ceramics that is excellent in air tightness and heat resistance, so that the electrolytic solution can be accommodated satisfactorily, and even when exposed to a temperature cycle, a gap is generated and the electrolytic solution is Never leakMoreover, since airtightness is maintained, it is possible to effectively prevent moisture, oxygen, or the like that deteriorates battery performance from entering the electrolytic solution from the outside.

  In addition, the substrate is not easily attacked by an electrolytic solution containing an organic solvent, an acid, and the like, and impurities dissolved from the substrate are not mixed in the electrolytic solution, so that the electrolytic solution is not deteriorated. For this reason, battery performance can be maintained satisfactorily.

  Furthermore, since a portion that is caulked through a resin as in the prior art is not required, the outer shape of the battery can be reduced to the limit, which is suitable for recent miniaturization.

  Further, by forming the first conductor layer and the second conductor layer on the lower surface, the first and second conductor layers are joined to the wiring conductor on the surface of the external electric circuit board via solder. Since the wiring conductor of the flat external electric circuit board and the battery can be easily connected, the mass production of the external electric circuit board is very good.

  Further, in the battery case of the present invention, the recess has a stepped portion formed on the inner surface due to the stepwise increase in the inner dimension toward the upper side of the base, and the stepped portion is recessed. The ceramic layers are formed at the corners over the entire circumference, so that the ceramic green sheets constituting the bases can be firmly adhered to each other, the airtight reliability of the bases is improved, and the electrolyte leaks more effectively. Can be prevented.

  The battery of the present invention is placed in close contact with the battery case having the above configuration, the positive electrode plate connected to the first metallization layer, and the upper surface of the positive electrode plate via an insulating sheet impregnated with an electrolyte. And having a negative electrode plate connected to the second metallization layer and a lid joined so as to cover the recess, airtight reliability using the battery case having the above-described configuration is achieved. High and excellent in mass productivity. In addition, desired battery performance can be exhibited, reliability is high, and charging and discharging can be performed stably over a long period of time.

  The battery case of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a recess is formed in the center of the upper surface, and the first conductor layer and the second conductor layer are independent of each other on the lower surface. The first metallization layer formed on the bottom surface of the recess, the second metallization layer formed around the recess on the upper surface of the substrate, the first metallization layer, and the first conductor layer. A second connection layer electrically connecting the second connection layer and the second connection layer electrically connecting the second connection layer and the second connection layer. Is not required to be formed between the inner surface and the bottom surface of the recess, the step inside the recess can be omitted, and the inside of the recess can be used widely and effectively. it can.

  Further, the battery of the present invention is in close contact with the battery case having the above configuration, the positive electrode plate connected to the first metallization layer, and the upper surface of the positive electrode plate via an insulating sheet impregnated with an electrolytic solution. A negative electrode plate mounted thereon, and a lid that is joined so as to cover the concave portion and at least the lower main surface is conductive, and is connected to the negative electrode plate and the second metallized layer. As a result, the airtight reliability using the battery case having the above configuration can be made high, the step inside the recess can be omitted, and the inside of the recess can be used widely and effectively. Can be In addition, the second metallization layer functions as a joining portion to which a lid for sealing the recesses in an airtight manner, and at least the lower main surface of the lid is conductive, so that the negative electrode plate By simply contacting the lower main surface of the lid, the negative electrode plate and the second metallized layer can be electrically connected to function as a conductive path. As a result, electrical connection between the second metallized layer and the negative electrode plate and hermetic sealing of the recesses can be performed in a single process, making the battery easy and suitable for mass production of batteries. It can be made.

  The electric double layer capacitor case of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a rectangular parallelepiped recess is formed in the center of the upper surface, and the first conductor layer and the second conductor layer on the lower surface. Are formed independently of each other, a first metallization layer formed on the bottom surface of the recess, and a second metallization layer formed on the top surface of the step formed between the inner surface and the bottom surface of the recess. And a first connecting conductor that electrically connects the first metallized layer and the first conductor layer, and a second connecting conductor that electrically connects the second metallized layer and the second conductor layer. As a result, the electrolytic solution is accommodated by a substrate made of ceramics that is excellent in air tightness and heat resistance, so that the electrolytic solution can be accommodated satisfactorily even when exposed to a temperature cycle. Arise There is no possibility that the electrolyte leakage. In addition, since airtightness is maintained, it is possible to effectively prevent moisture, oxygen, and the like that deteriorate the performance of the electric double layer capacitor from entering the electrolyte from the outside.

  Further, by forming the first conductor layer and the second conductor layer on the lower surface, the first and second conductor layers are joined to the wiring conductor on the surface of the external electric circuit board via solder. Since the wiring conductor of the flat external electric circuit board and the battery can be easily connected, the mass production of the external electric circuit board is extremely excellent.

  Further, in the case for the electric double layer capacitor of the present invention, the recess has a stepped portion formed on the inner surface due to the stepwise increase in the inner dimension toward the upper side of the substrate. Since the ceramic layer is formed on the corners of the recesses over the entire circumference, the ceramic green sheets constituting the base can be firmly adhered to each other, the airtight reliability of the base is improved, and the electrolyte leaks. This can be prevented more effectively.

  The electric double layer capacitor of the present invention includes an electric double layer capacitor case having the above structure, a first electrode connected to the first metallization layer, and a separator in which the upper surface of the first electrode is impregnated with an electrolyte. The second electrode connected to the second metallization layer and the lid joined so as to cover the concave portion. The airtight reliability using the multilayer capacitor case is high and the mass productivity is excellent. Further, the desired performance of the electric double layer capacitor can be exhibited, the reliability is high, and charging and discharging can be stably performed over a long period of time.

  The case for the electric double layer capacitor of the present invention is formed by laminating and firing a plurality of ceramic green sheets, a recess is formed in the center of the upper surface, and the first conductor layer and the second conductor layer are formed on the lower surface. A base formed independently of each other, a first metallization layer formed on the bottom surface of the recess, a second metallization layer formed around the recess on the top surface of the base, the first metallization layer, and the first And a second connection conductor for electrically connecting the second metallization layer and the second conductor layer. It is not necessary to form a metallized layer between the inner side surface and the bottom surface of the recess, the step inside the recess can be omitted, and the inside of the recess can be used widely and effectively. Can be miniaturized.

  The electric double layer capacitor of the present invention includes an electric double layer capacitor case having the above structure, a first electrode connected to the first metallization layer, and a separator in which an upper surface of the first electrode is impregnated with an electrolyte. The second electrode placed so as to be in close contact with each other and joined so as to cover the recess, and at least the lower main surface is made conductive, and is connected to the second electrode and the second metallized layer. Since the airtight reliability using the electric double layer capacitor case having the above-described structure can be improved, the step inside the recess can be omitted, and the inside of the recess can be effectively and widely used. Since it can be utilized, the external shape of the electric double layer capacitor can be reduced in size. The lid serves to join a lid for hermetically sealing the recess, and at least the lower main surface of the lid is made conductive so that the second electrode is the lower main surface of the lid The second electrode and the second metallized layer can be electrically connected only by being brought into contact with each other and function as a conductive path. As a result, the electrical connection between the second metallized layer and the second electrode and the hermetic sealing of the recesses can be performed in a single process, facilitating the production of the electric double layer capacitor, and the electric double layer. It can be made suitable for mass production of capacitors.

  An example of an embodiment of a battery case of the present invention will be described in detail below. 1A is a cross-sectional view showing an example of an embodiment of a battery case of the present invention, and FIG. 1B is a plan view of the battery case of FIG. FIG. 2 is a cross-sectional view showing an example of an embodiment of the battery of the present invention.

  As shown in FIG. 1, the battery case of the present invention is formed by laminating and firing a plurality of ceramic green sheets 1-B, and a concave portion 1a having a rectangular parallelepiped shape, a prismatic shape, a cylindrical shape or the like is formed at the center of the upper surface. Formed on the bottom surface of the first conductor layer 1d and the second conductor layer 1e independently of each other, the first metallized layer 1b formed on the bottom surface of the recess 1a, The first metallized layer 1c formed on the top surface of the step 1-A formed between the side surface and the bottom surface, the first metallized layer 1b and the first conductor layer 1d are electrically connected. Connecting conductor 2b and second connecting conductor 2c that electrically connects second metallized layer 1c and second conductor layer 1e, and concave portion 1a is directed to the upper side of substrate 1. Inner surface due to increasing internal dimensions in steps Are formed stepped portions 1-C, the ceramic layer 4 is formed over the entire periphery recessed corner of the step portion 1-C.

  Further, as shown in FIG. 2, the battery C of the present invention includes a battery case having the above-described configuration, a positive electrode plate B-1 connected to the first metallized layer 1b, and the positive electrode plate B-1. The negative electrode plate B-2 connected to the second metallized layer 1c and the concave portion 1a are covered while being placed in close contact with the upper surface of the metal plate via an insulating sheet B-3 impregnated with the electrolytic solution B-4. In this way, the lid 3 is joined.

  In the battery case of the present invention, since the substrate 1 is made of ceramics, the substrate 1 is not easily attacked by the electrolytic solution B-4 containing an organic solvent, an acid, or the like. Accordingly, impurities dissolved from the substrate 1 in the electrolytic solution B-4 are present. It does not mix and degrade electrolyte B-4. For this reason, the battery case which can maintain battery performance favorably can be obtained.

  Further, when the electrolytic solution B-4 is accommodated by the base 1 made of ceramics having excellent airtightness and excellent heat resistance, the electrolytic solution B-4 can be satisfactorily accommodated and exposed to a temperature cycle. However, there is no gap and electrolyte B-4 does not leak. Moreover, since airtightness is maintained, it can suppress effectively that the water | moisture content, oxygen, etc. which degrade battery performance permeate into electrolyte B-4 from the outside.

  Further, since the first and second conductor layers 1d and 1e are formed on the lower surface of the base 1, the first and second conductor layers 1d and 1e are soldered to the wiring conductor on the surface of the external electric circuit board. By joining them, the wiring conductor of the flat external electric circuit board and the battery can be easily connected, so that the mass productivity of the external electric circuit board is improved.

  Further, the recess 1a has a stepwise increase in the inner dimension of the opening as the recess 1a provided in the ceramic green sheet 1-B constituting the substrate 1 moves upward. A step portion 1-C is formed on the inner side surface, and the ceramic layer 4 is formed over the entire periphery at the recessed corner portion of the step portion 1-C. B can be firmly adhered to each other, the airtight reliability of the substrate 1 can be improved, and the electrolyte B-4 can be more effectively prevented from leaking.

  Further, the height of the paste-like ceramic layer 4 after firing is preferably 5 to 50 μm. With this configuration, the first metallized layer 1b and the second metallized layer 1c are ceramic green sheets on the outer periphery of the recess. It is possible to effectively prevent a gap from being generated between the ceramic green sheets 1-B at the portion entering the 1-B layer. Therefore, this configuration can provide a battery case with better airtight reliability.

  Moreover, the other example of embodiment of the battery case and battery of this invention is shown in FIG. In the figure, (a) is a cross-sectional view of the battery case, and (b) is a plan view of the battery case. FIG. 4 is a cross-sectional view showing another example of the embodiment of the battery D of the present invention. 3 and 4, the same reference numerals are assigned to the same parts as those in FIGS. 1 and 2.

  In another example of the embodiment of the battery case of the present invention, a plurality of ceramic green sheets 1-B are laminated and fired, and a concave portion 1a having a rectangular parallelepiped shape, a prismatic shape, a cylindrical shape or the like is formed at the center of the upper surface. Formed on the bottom surface of the first conductor layer 1d and the second conductor layer 1e independently of each other, the first metallized layer 1b formed on the bottom surface of the recess 1a, and the substrate 1 The second metallized layer 1c formed around the concave portion 1a on the upper surface of the first metal, the first connection conductor 2b and the second metallized electrically connecting the first metallized layer 1b and the first conductor layer 1d. The second connecting conductor 2c that electrically connects the layer 1c and the second conductor layer 1e is provided, and the inner dimension of the recess 1a gradually increases as it goes upward of the base body 1. Stepped portion 1-C on the inner surface It made are and the ceramic layer 4 is formed over the entire periphery recessed corner of the step portion 1-C.

  In the embodiment of the battery case of the present invention, since the second metallized layer 1c is formed around the recess 1a on the upper surface of the substrate 1, in addition to the embodiment of FIG. Since the step 1-A inside 1a can be omitted and the inside of the recess 1a can be used widely and effectively, the outer shape of the battery case can be reduced in size.

  Further, as shown in FIG. 4, the battery D of the present invention includes a battery case having the above-described configuration, a positive electrode plate B-1 connected to the first metallized layer 1b, and the positive electrode plate B-1. And the negative electrode plate B-2 placed so as to be in close contact with the upper surface of the substrate through the insulating sheet B-3 impregnated with the electrolytic solution B-4, so as to cover the recess 1a and at least the lower main plate The surface is made conductive, and includes a negative electrode plate B-2 and a lid 3 connected to the second metallized layer 1c.

  In the present embodiment, the outer shape of the substrate 1 is a rectangular parallelepiped having a length of 0.5 to 10 mm, a width of 2 to 20 mm, and a depth of 2 to 20 mm. Needless to say, the shape is not limited to a rectangular parallelepiped, for example, a cylindrical shape having a length of 0.5 to 10 mm and a diameter of 2 to 20 mm, or any other suitable shape depending on the application.

  In addition, the battery case and the batteries C and D of the present invention are illustrated in the shape of a rectangular parallelepiped as shown in FIGS. However, there is no problem, and it is possible to obtain a desired shape by changing the shape of the concave portion 1a, the conductor layer, and the like in a plan view.

Such a base | substrate 1 consists of ceramics, such as an alumina-type sintered compact, and is produced as follows. For example, when the substrate 1 is made of an alumina sintered body, an organic binder suitable for raw material powders such as aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), magnesium oxide (MgO), and calcium oxide (CaO). Add a solvent and mix to form a slurry. This slurry is formed into a ceramic green sheet 1-B by a doctor blade method or a calender roll method, and cut into a required size. Next, in order to form the recess 1a, the step 1-A, the step 1-C and the like in the plurality of ceramic green sheets 1-B selected from them, an appropriate punching process is performed.

  Then, a metal paste mainly composed of a metal powder such as tungsten (W) is printed and applied to these ceramic green sheets 1-B to form a first metallized layer 1b, a first connection conductor 2b, and a first conductor layer. 1d, the second metallized layer 1c, the second connection conductor 2c, the second conductive layer 1e, and the like are formed on the printed pattern, and then the ceramic green sheet 1-B on which these printed patterns are formed is laminated. And the base | substrate 1 provided with the conductor layer is produced by apply | coating the paste-form slurry used as the ceramic layer 4 over the perimeter of the recessed corner | angular part of the level | step-difference part 1-C, and baking at the temperature of about 1600 degreeC.

  The second metallized layer 1c may be formed on any upper surface of the inner stepped portion 1-C, but is usually formed on the upper surface of the step 1-A closest to the upper surface of the substrate 1. Thereby, the protrusion part electrically connected with the 2nd metallization layer 1c of the negative electrode board B-2 can be located in the upper surface side of a battery case, and the distance with the positive electrode board B-1 is separated as much as possible. It can be made easy.

  Here, the first connecting conductor 2b and the second connecting conductor 2c are formed on the inner surface of the punched portion by punching the outer peripheral portion of the ceramic green sheet 1-B serving as the base 1 in advance into a groove. It may be in the form of a castellation conductor. With this configuration, the first connection conductor 2b and the second connection conductor 2c can be efficiently manufactured using a conventionally known castellation conductor formation method, and a groove can be formed at the same time as the punching process. 1 can be accurately formed at a desired position on the side surface of the outer peripheral portion.

  By using the castellation conductor, the width can be increased compared to the case where the first connection conductor 2b and the second connection conductor 2c are simply formed on the side surface of the outer peripheral portion of the base 1, and the electrical resistance is reduced. Thus, it is possible to effectively prevent the battery performance from being impaired in the first connection conductor 2b and the second connection conductor 2c.

  The first conductor layer 1d is electrically connected to the first metallization layer 1b via the first connection conductor 2b, and the second conductor layer 1e is connected to the second metallization via the second connection conductor 2c. It is electrically connected to the layer 1c. The first conductor layer 1d is used as the positive electrode of the battery, and the second conductor layer 1e is used as the negative electrode. The first conductor layer 1d and the second conductor layer 1e are joined to the wiring conductor on the surface of the external electric circuit board via solder, whereby the battery is electrically connected to the external electric circuit.

  Further, the exposed surfaces of these conductor layers formed on the substrate 1 thus manufactured have a metal excellent in corrosion resistance and wettability with solder, specifically nickel (thickness 1 to 12 μm). A Ni) layer and a gold (Au) layer having a thickness of 0.3 to 5 μm are preferably sequentially deposited by a plating method or the like. Thereby, it can suppress effectively that the metal component of the 1st metallization layer 1b and the 2nd metallization layer 1c which were especially formed inside the case for batteries is easily eluted by the voltage by charging / discharging. In addition, the first and second conductor layers 1d and 1e have improved wettability with solder, and the bonding strength with the wiring conductor on the external electric circuit board via the solder becomes stronger.

  If the thickness of the Ni layer is less than 1 μm, it becomes difficult to prevent the oxidative corrosion of each conductor made of the metallized layer and to effectively prevent the metal component from eluting from the conductor, and the battery performance deteriorates. It becomes easy to do. On the other hand, if the thickness of the Ni layer exceeds 12 μm, it takes a long time to form the plating, so that the mass productivity is likely to be lowered and the electric resistance is likely to be increased.

  Further, if the thickness of the Au layer is less than 0.3 μm, it is difficult to form an Au layer having a uniform thickness, and a portion where the Au layer is extremely thin or a portion where the Au layer is not formed is likely to occur. The effect of preventing oxidative corrosion and the wettability with solder are likely to decrease. If the thickness of the Au layer exceeds 5 μm, it takes a lot of time to form the plating, and the mass productivity tends to decrease.

  Further, the ceramic layer 4 is formed in a portion where the first metallized layer 1b and the second metallized layer 1c enter the interlayer of the ceramic green sheet 1-B on the outer peripheral portion of the recess 1a. Even at the site where the first metallized layer 1b and the second metallized layer 1c that are difficult to adhere to each other between the ceramic green sheets 1-B on the outer periphery of the recess 1a, the airtight reliability of the substrate 1 is improved. It is possible to effectively prevent the electrolyte from leaking. In addition, since the ceramic layer 4 can enhance the airtight reliability between the layers, the first metallized layer and the second metallized layer can be made as wide as possible, and the first metallized layer 1b and the second metallized layer can be made as wide as possible. The resistance value of the metallized layer 1c can be minimized.

The ceramic layer 4 is composed mainly of, for example, a material for forming the base 1. For example, when the substrate 1 is made of an alumina sintered body, the ceramic layer 4 is also alumina, and an appropriate organic binder, solvent, or the like is added to and mixed with raw material powders such as Al ₂ O ₃ , SiO ₂ , MgO, and CaO. To form a paste. Then, this paste-like material is printed and applied, and the first metallized layer 1b, the first connection conductor 2b, the first conductor layer 1d, the second metallization layer 1c, the second connection conductor 2c, the second By firing at a high temperature at the same time as the metal paste that becomes a printed pattern to be a conductor layer such as the conductor layer 1e, the ceramic green sheets 1-B can be brought into close contact with each other and the inside of the substrate 1 can be kept airtight.

  The height of the fired ceramic layer 4 is preferably 5 to 50 μm. With this configuration, the first metallized layer 1b and the second metallized layer 1c are formed on the outer periphery of the ceramic green sheet 1-B of the recess. It is possible to effectively prevent a gap from being generated between the ceramic green sheets 1-B at a portion that enters between the layers. If the thickness is less than 5 μm, it tends to be difficult to fill the gap between the first metallized layer 1 b and the second metallized layer 1 c that enter the interlayer of the ceramic green sheet 1 -B on the outer periphery of the concave portion. In the case of exceeding, it tends to be difficult to form the ceramic layer 4.

  Next, an example of an embodiment of the battery of the present invention will be described in detail below.

The positive electrode plate B-1 is a plate or sheet including a positive electrode active material made of LiCoO ₂ or LiMn ₂ O ₄ and a conductive material such as acetylene black or graphite, and the negative electrode plate B-2 Is a plate or sheet including a negative electrode active material made of a carbon material such as coke or carbon fiber.

  The positive electrode plate B-1 is obtained by adding a binder such as polytetrafluoroethylene or polyvinylidene fluoride to the positive electrode active material added with the conductive material, and mixing it to form a slurry. This is a well-known doctor blade method. And the like, and then the sheet is cut into, for example, a square shape or a circular shape.

  Similarly, the negative electrode plate B-2 is made into a slurry by adding and mixing a binder such as polytetrafluoroethylene or polyvinylidene fluoride to the negative electrode active material, and this is made into a sheet using a known doctor blade method or the like. The sheet is then formed into a rectangular shape or a circular shape.

  The insulating sheet B-3 is made of a non-woven fabric made of polyolefin fiber, a microporous membrane made of polyolefin, and the like, impregnated with the electrolytic solution B-4, and between the positive electrode plate B-1 and the negative electrode plate B-2. By being disposed between the positive electrode plate B-1 and the negative electrode plate B-2, the electrolytic solution between the positive electrode plate B-1 and the negative electrode plate B-2 is prevented. The movement of B-4 is enabled to allow a current to flow.

  The electrolytic solution B-4 is obtained by, for example, dissolving a lithium salt such as lithium tetrafluoroborate or an acid such as hydrochloric acid, sulfuric acid, or nitric acid in an organic solvent such as dimethoxyethane or propylene carbonate.

  Such an electrolytic solution B-4 is highly corrosive and soluble, but by using the battery case of the present invention, the substrate 1 is excellent in chemical resistance. The electrolyte solution B-4 is not easily affected by the electrolyte solution B-4, and impurities dissolved out from the battery case are not mixed in the electrolyte solution B-4 so that the electrolyte solution B-4 is not deteriorated. be able to.

  The electrolytic solution B-4 is injected into the inside of the battery C from the upper surface of the recess 1a using an injection means such as a syringe in a container filled with, for example, argon (Ar) gas that hardly contains moisture. And the inside of the battery C can be sealed airtight by welding the cover 3 to the upper surface of the base | substrate 1 after injection | pouring.

  The lid 3 is made of ceramic such as alumina sintered body, mullite sintered body, aluminum (Al), copper (Cu), carbon, iron (Fe) -Ni-cobalt (Co) alloy, Fe-Ni alloy, etc. The recess 1a is covered on the upper surface of the substrate 1 by a method such as brazing using Al brazing, silver (Ag) brazing, Au-tin (Sn) soldering, or bonding using a resin adhesive or the like. To be joined. Or it consists of ceramics, such as an alumina sintered compact and a mullite sintered compact.

  In the metal case that has been used conventionally, as shown in FIG. 5, the positive electrode can 11 and the negative electrode can 12 are integrated by caulking them with a gasket 15 made of polypropylene resin or the like. In the conventional battery, the size of about 2 mm is necessary for the caulking portion of the positive electrode can 11, the negative electrode can 12, and the separator 14 due to the presence of the portion. In addition, since there is no caulking portion, the outer shapes of the batteries C and D can be reduced, which can greatly contribute to miniaturization of the portable device. Further, the airtight reliability is high and the mass productivity is excellent.

  In addition, since the lid 3 can be firmly bonded to the upper surface of the substrate 1 having excellent airtightness and heat resistance by a resin adhesive such as polypropylene, solder bonding, seam welding bonding or the like, the electrolyte can be stored well. Even when exposed to a temperature cycle or the like, a gap is not generated and the electrolyte does not leak. Moreover, since airtightness is maintained, it is possible to effectively suppress moisture, oxygen, and the like that deteriorate battery performance from entering the electrolyte from the outside.

  Further, in the battery D, the step 1-A inside the recess 1a can be omitted, and the inside of the recess 1a can be used widely and effectively, so that the outer shape of the battery can be reduced in size. Furthermore, since the second metallized layer 1c functions as a joint to which the lid 3 for sealing the recess 1a in an airtight manner is joined, and at least the lower main surface of the lid 3 is conductive, By merely bringing the negative electrode plate B-2 into contact with the lower main surface of the lid 3, the negative electrode plate B-2 and the second metallized layer 1c can be electrically connected, and function as a conductive path. As a result, the electrical connection between the second metallized layer 1c and the negative electrode plate B-2 and the hermetic sealing of the recess 1a can be performed in one step, which facilitates the production of the battery. It can be made suitable for mass production.

  Preferably, the lid 3 is made of the same material as the base 1 such as an alumina sintered body and a mullite sintered body, in which a metallized layer such as W is formed on almost the entire lower main surface of the base 1 side. It should be made of ceramics. The metallized layer 3a is electrically connected to the second metallized layer 1c and joined to the upper surface of the base 1 so as to cover the recess 1a. With this configuration, the upper main surface of the lid 3 is not made conductive, and unnecessary current can be prevented from flowing through the upper surface of the lid 3. Therefore, even if a conductive member contacts the upper main surface of the lid 3, it is possible to effectively prevent problems such as an electrical short circuit from occurring. Further, since the thermal expansion coefficient of the lid 3 is substantially the same as the thermal expansion coefficient of the base body 1, even when heat is applied to the battery case, the stress due to the thermal expansion difference is large at the joint between the base body 1 and the lid body 3. It is possible to prevent the occurrence of breakage such as cracks in the base body 1 and to effectively prevent the breakage of the base body 1 and to provide a battery case having excellent hermetic reliability.

  Next, the electric double layer capacitor case and electric double layer capacitor C of the present invention have the same configuration and operational effects as the battery case and battery C described above.

  In other words, the electric double layer capacitor case of the present invention has a rectangular parallelepiped, prismatic or cylindrical recess 1 a formed at the center of the upper surface of the substrate 1. The first metallized layer 1b is formed on the bottom surface of the recess 1a of the substrate 1, and the second metallized layer 1c is formed on the upper surface of the step 1-A formed between the inner surface and the bottom surface of the recess 1a. The first conductor layer 1d and the second conductor layer 1e are formed independently of each other on the lower surface of the first conductor conductor 2b for electrically connecting the first metallized layer 1b and the first conductor layer 1d. And the 2nd connection conductor 2c which electrically connects the 2nd metallization layer 1c and the 2nd conductor layer 1e is formed. The concave portion 1a has a stepped portion 1-C formed on the inner surface due to the stepwise increase in inner dimension toward the upper side of the base 1, and a concave corner of the stepped portion 1-C. A ceramic layer 4 is formed over the entire circumference.

  In addition, the electric double layer capacitor C of the present invention is the first electric double layer capacitor case and the first metallized layer 1b placed on the upper surface of the first metallized layer 1b and electrically connected to the first metallized layer 1b. The electrode B-1 is placed in close contact with the first electrode B-1 via a separator B-3 impregnated with the electrolytic solution B-4, and is electrically connected to the second metallized layer 1c. The connected second electrode B-2 and the lid 3 joined so as to cover the recess 1a are provided.

  In addition, another example of the electric double layer capacitor case and electric double layer capacitor embodiment of the present invention has the same configuration and operational effects as the battery case and battery D described above.

  That is, in the case for the electric double layer capacitor of the present invention, a concave portion 1a having a rectangular parallelepiped shape, a prismatic shape, a cylindrical shape or the like is formed in the central portion of the upper surface of the base body 1 formed by laminating and firing a plurality of ceramic green sheets. . The first metallized layer 1b is formed on the bottom surface of the recess 1a of the substrate 1, the second metallized layer 1c is formed around the recess 1a on the upper surface of the substrate 1, and the first conductor layer 1d and the second metal layer 1c are formed on the lower surface of the substrate 1. Are formed independently of each other, and the first connection conductor 2b, the second metallization layer 1c, and the second conductor electrically connect the first metallization layer 1b and the first conductor layer 1d. A second connection conductor 2c that electrically connects the layer 1e is formed. The concave portion 1a has a stepped portion 1-C formed on the inner surface due to the stepwise increase in inner dimension toward the upper side of the base 1, and a concave corner of the stepped portion 1-C. A ceramic layer 4 is formed over the entire circumference.

  According to this embodiment, since the step 1-A inside the recess 1a can be omitted, the inside of the recess 1a can be used widely and effectively, so that the outer shape of the electric double layer capacitor case can be reduced in size.

  In addition, the electric double layer capacitor D of the present invention is the electric double layer capacitor case configured as described above and a first metallized layer 1b placed on the upper surface of the first metallized layer 1b and electrically connected to the first metallized layer 1b. One electrode B-1 and a second electrode B-2 placed so as to be in close contact with the upper surface of the first electrode B-1 via a separator B-3 impregnated with an electrolyte B-4; The lid 3 is joined so as to cover the recess 1a, and at least the lower main surface is conductive, and the lid 3 is connected to the second electrode B-2 and the second metallized layer 1c. .

  According to this embodiment, the second metallized layer 1c functions as a joining portion to which the lid 3 for hermetically sealing the recess 1a is joined, and at least the lower main surface of the lid 3 is conductive. For this reason, the second electrode B-2 can be electrically connected to the second metallized layer 1c only by bringing the second electrode B-2 into contact with the lower main surface of the lid 3, and the conductive property is improved. Functions as a road. As a result, the electrical connection between the second metallized layer 1c and the negative electrode plate B-2 and the hermetic sealing of the recess 1a can be performed in one step, and the production of the electric double layer capacitor is facilitated. It can be made suitable for mass production of electric double layer capacitors.

  Preferably, the lid 3 has a metallized layer such as W formed on almost the entire lower main surface of the base 1 side, and is made of ceramics of the same material as the base 1 such as an alumina sintered body and a mullite sintered body. It is good. The metallized layer 3a is electrically connected to the second metallized layer 1c and joined to the upper surface of the base 1 so as to cover the recess 1a. With this configuration, the upper main surface of the lid 3 is not made conductive, and unnecessary current can be prevented from flowing through the upper surface of the lid 3. Therefore, even if a conductive member contacts the upper main surface of the lid 3, it is possible to effectively prevent problems such as an electrical short circuit from occurring. Further, since the thermal expansion coefficient of the lid 3 is substantially the same as the thermal expansion coefficient of the base body 1, even when heat is applied to the battery case, the stress due to the thermal expansion difference is large at the joint between the base body 1 and the lid body 3. It is possible to prevent the occurrence of breakage such as cracks in the base body 1 and to effectively prevent the breakage of the base body 1 and to provide a battery case having excellent hermetic reliability.

In the electric double layer capacitors C and D of the present invention, the first electrode B-1 and the second electrode B-2 are obtained by, for example, carbonizing activation of phenol resin fibers (novoloid fibers). This fiber is made by contacting it with an activation gas such as high-temperature steam under a high-temperature atmosphere of 800 to 1000 ° C., and gasifies a part of volatile components in the carbide or carbon atoms, mainly having a fine structure of 1 to 10 nm. To develop an internal surface area of 1 × 10 ⁶ m ² / kg or more. The electric double layer capacitor C of the present invention has no polarity in the first and second conductor layers 1d and 1e, and can be used as an anode on the first conductor layer 1d side and a cathode on the second conductor layer 1e side, The reverse polarity can also be used.

The electrolytic solution B-4 is, for example, a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) or a quaternary ammonium salt such as tetraethylammonium tetrafluoroborate ((C ₂ H ₅ ) ₄ NBF ₄ ) using propylene carbonate. It is dissolved in a solvent such as (PC) or sulfolane (SLF).

  In addition, for the separator B-3, for example, glass fiber, polyphenylene sulfide, polyethylene terephthalate, polyamide or other heat-resistant resin is used.

  The electric double layer capacitor C is mounted on the upper surface of the first metallized layer 1b so that the first electrode B-1, the separator B-3, the second electrode B-2, and the lid 3 are in close contact with each other. Then, after injecting the electrolytic solution B-4, the concave portion 1a is formed on the upper surface of the substrate 1 by a method such as brazing using Al brazing, Ag brazing, Au—Sn solder or the like, or bonding using a resin adhesive or the like. The electric double layer capacitor C is joined so as to cover it.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, the battery case or the electric double layer capacitor C using the battery case having one recess 1a or the electric double layer capacitor case has been described, but as the battery case or electric double layer capacitor case having a plurality of recesses 1a. In this case, the lid 3 may be a single lid 3 that covers all the recesses 1a, or a plurality of lids 3 that cover the respective recesses 1a may be attached. When the battery case or the electric double layer capacitor case A having a plurality of recesses 1a is used as described above, the battery or the electric double layer capacitor C produced in each of the recesses 1a is connected in parallel so as to increase the capacity. A battery or an electric double layer capacitor C can be used, and a battery C that can supply a high voltage by being connected in series can be used.

(A) is sectional drawing which shows an example of embodiment of the case for batteries of this invention, and the case for electric double layer capacitors, (b) is a top view of (a). It is sectional drawing which shows an example of embodiment of the battery and electric double layer capacitor of this invention. (A) is sectional drawing which shows the other example of embodiment of the case for batteries of this invention, and the case for electric double layer capacitors, (b) is a top view of (a). It is sectional drawing which shows the other example of embodiment of the battery and electric double layer capacitor of this invention. It is sectional drawing which shows the example of the conventional battery.

Explanation of symbols

1: Base 1a: Recess 1-A: Step 1-B: Ceramic green sheet 1-C: Step 1b: First metallized layer 1c: Second metallized layer 1d: First conductor layer 1e: Second Conductor layer 2b: first connection conductor 2c: second connection conductor 3: lid body 4: ceramic layer B-1: positive electrode plate, first electrode B-2: negative electrode plate, second electrode B- 3: Insulating sheet, separator B-4: Electrolytic solution C, D: Battery, Electric double layer capacitor

Claims (8)

A plurality of ceramic green sheets are laminated and fired, a recess having a recess formed in the central portion of the upper surface, and a first conductor layer and a second conductor layer formed independently of each other on the lower surface; A first metallization layer formed on the bottom surface; a second metallization layer formed on the top surface of the step formed between the inner surface and the bottom surface of the recess; the first metallization layer and the first metallization layer A first connection conductor that electrically connects the conductor layer and a second connection conductor that electrically connects the second metallization layer and the second conductor layer, and the recess A step portion is formed on the inner surface due to the stepwise increase in the inner dimension toward the upper side of the base body, and a ceramic layer is formed over the entire periphery at the recessed corner portion of the step portion. Battery case characterized by The battery case according to claim 1, the positive electrode plate connected to the first metallization layer, and the positive electrode plate are placed so as to be in close contact with an upper surface of the positive electrode plate via an insulating sheet impregnated with an electrolytic solution. And a negative electrode plate connected to the second metallized layer and a lid joined so as to cover the recess. A plurality of ceramic green sheets are stacked and fired, a recess is formed in the center of the upper surface, and a first conductor layer and a second conductor layer are formed independently on the lower surface, and the recess The first metallized layer formed on the bottom surface, the second metallized layer formed around the recess on the top surface of the base, the first metallized layer, and the first conductor layer electrically A first connection conductor to be connected and a second connection conductor to electrically connect the second metallized layer and the second conductor layer, and the concave portion faces the upper side of the base body. Accordingly, a stepped portion is formed on the inner side surface due to the stepwise increase in internal dimensions, and a ceramic layer is formed over the entire circumference at the recessed corner portion of the stepped portion. Battery case. The battery case according to claim 3, the positive electrode plate connected to the first metallization layer, and an upper surface of the positive electrode plate placed so as to be in close contact via an insulating sheet impregnated with an electrolytic solution. A negative electrode plate, and a lid that is joined so as to cover the concave portion and that has at least a lower main surface made conductive and connected to the negative electrode plate and the second metallized layer. A battery characterized by that. A plurality of ceramic green sheets are laminated and fired, a recess having a recess formed in the central portion of the upper surface, and a first conductor layer and a second conductor layer formed independently of each other on the lower surface; A first metallization layer formed on the bottom surface; a second metallization layer formed on the top surface of the step formed between the inner surface and the bottom surface of the recess; the first metallization layer and the first metallization layer A first connection conductor that electrically connects the conductor layer and a second connection conductor that electrically connects the second metallization layer and the second conductor layer, and the recess A step portion is formed on the inner surface due to the stepwise increase in the inner dimension toward the upper side of the base body, and a ceramic layer is formed over the entire periphery at the recessed corner portion of the step portion. Electric double layer key Case for Pashita. The case for an electric double layer capacitor according to claim 5, the first electrode connected to the first metallization layer, and the upper surface of the first electrode are in close contact with each other through a separator impregnated with an electrolyte. An electric double layer capacitor comprising: a second electrode placed and connected to the second metallization layer; and a lid joined so as to cover the recess. A plurality of ceramic green sheets are laminated and fired, a recess having a recess formed in the central portion of the upper surface, and a first conductor layer and a second conductor layer formed independently of each other on the lower surface; The first metallized layer formed on the bottom surface, the second metallized layer formed around the recess on the top surface of the base, the first metallized layer, and the first conductor layer electrically A first connection conductor to be connected and a second connection conductor to electrically connect the second metallized layer and the second conductor layer, and the recess faces upward of the base body. Accordingly, a stepped portion is formed on the inner surface due to the stepwise increase of the inner dimension, and a ceramic layer is formed over the entire circumference at the recessed corner portion of the stepped portion. Case for electric double layer capacitor. The case for an electric double layer capacitor according to claim 7, the first electrode connected to the first metallization layer, and an upper surface of the first electrode are in close contact with each other through a separator impregnated with an electrolyte. The lid that is joined to the placed second electrode so as to cover the recess, and at least the lower main surface is conductive, and is connected to the second electrode and the second metallization layer. An electric double layer capacitor comprising:

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