JP2018077948A - Package for electrochemical cell, electrochemical cell arranged by use thereof, and method for manufacturing package for electrochemical cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package for an electrochemical cell, which is superior in mass productivity and reliability, by using a protection film superior in coatability.SOLUTION: A package for an electrochemical cell for putting a power-generating element in a base container including a base material of an insulator and hermetically sealing the base container comprises: a metal via wire 5c formed on a bottom of the base container and having its surface inside the base container; a plating layer 7 formed on the surface of the via wire 5c; and a conductive protection film 8 formed to continuously cover the via wire 5c with the plating layer 7 formed thereon and the bottom. When in the geometry in a sectional view taken along the center of a via-hole where the via wire 5c is formed, a bisector of an angle formed by a virtual line A and a virtual line B is defined as a virtual line C, where the virtual line A is a tangent line running through the bottom of the base container at a position where the bottom of the base container is bounded by an end of the plating layer 7, and the virtual line B is a tangent line running through the end of the plating layer 7, the virtual line C is directed vertically upward so as to be tilted by over 45° with respect to an outside bottom face of the base container.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a package for an electrochemical cell such as a battery or an electric double layer capacitor.

  As a package used for an electrochemical cell such as a battery or an electric double layer capacitor, a package configuration using ceramics as a main material is known. This package is formed by sealing a ceramic base made of alumina or the like with a lid made of a metal or alloy whose thermal expansion coefficient is close to that of the base. Since such a package configuration is excellent in cell sealing, the long-term reliability of the electrochemical cell can be improved.

  In addition, a connection terminal for electrically connecting to a circuit board or the like of a mounted device to be mounted is formed on the outer bottom surface of the ceramic substrate. And this connection terminal is electrically connected with the electrode accommodated in the inside of a package via the wiring formed in the ceramic base | substrate. By setting it as such a structure, the electrochemical cell which can be surface-mounted can be provided.

  Incidentally, the wiring formed on the surface or inside of the ceramic substrate is formed by integrally firing a metal paste applied to or embedded in a ceramic green sheet and the ceramic green sheet. As such a wiring material, a metal such as tungsten or molybdenum having a high melting point is used. Then, in order to improve the bonding with the circuit board on which the electrochemical cell is mounted by solder bonding or wire bonding with a noble metal such as gold, the surface of the metal such as tungsten or molybdenum is made of gold or nickel. A plating layer is formed.

  Also in the package, a plating layer of gold or nickel is formed on the exposed surface of a metal such as tungsten or molybdenum. When such a wiring and plating layer are electrically connected to the positive electrode of the cell and have a positive potential, there is a risk of anodic corrosion and the cell becoming inoperable due to disconnection of the wiring. For this reason, in order to protect these materials from anode corrosion, valve metals, such as aluminum, carbon materials, etc. are used as a protective film.

  On the other hand, if the protective film is not sufficiently coated, the electrolyte solution penetrates into the protective film and reaches the through electrode and the like, and causes anode corrosion. Measures have been studied. For example, in the configuration in which the outer peripheral portion of the metallized layer to be a wiring is covered with a ceramic coat layer, the thickness of the ceramic coat layer is made thicker than the plating layer formed in a place not covered with this ceramic coat layer, It has been proposed to continuously form a conductive layer (protective film) made of zinc or the like (see Patent Document 1).

JP 2007-5278 A

  Thus, when producing a structure in which a ceramic coating layer is formed so as to straddle the ceramics on the inner bottom surface and wiring made of tungsten or the like exposed on the inner bottom surface of the package, a metal paste for wiring is formed on the ceramic green sheet. After applying, and further applying a ceramic paste to be a ceramic coat layer, it is integrally formed by firing. At this time, due to the difference in expansion amount at the firing temperature, warpage and peeling of the ceramic coat layer may occur, and reliability and mass productivity may be reduced.

  In addition, increasing the number of steps for forming such a ceramic coat layer also has a problem in that it causes a decrease in mass productivity such as an increase in cost and an increase in man-hours.

  In view of such problems, an object of the present invention is to provide an electrochemical cell package that is excellent in mass productivity and reliability by using a protective film that is excellent in covering properties.

  As a result of intensive studies, the inventors have found that if the inclination angle of the bottom surface of the container and the inclination angle of the plating layer have a predetermined correspondence at the end of the wiring, sufficient coverage of the protective film can be ensured. It has come.

  That is, the electrochemical cell package according to the present invention is a package for an electrochemical cell in which a power generation element is accommodated and sealed in a base container including an insulating base material, and the base is disposed at the bottom of the base container. A metal via wiring having a surface is formed on the inner side of the container, a plating layer is formed on the surface of the via wiring, and the via wiring on which the plating layer is formed and the bottom are continuously formed. A conductive protective film is formed to cover the bottom of the base container at a position where the bottom of the base container and the end of the plating layer are in contact with each other in a cross-sectional shape passing through the center of the via hole in which the via wiring is formed. Assuming a virtual line A that is a tangent line passing through and a virtual line B that is a tangent line passing through the end of the plated layer, the bisector of the angle formed by the virtual line A and the virtual line B is defined as a virtual line C. When Characterized in that said virtual line C is directed vertically upward so as to be inclined beyond 45 ° to the outside bottom of the base container.

  According to the present invention, at the position of the end portion of the wiring, the straight line that bisects the angle formed by the inclination of the bottom surface of the container and the inclination of the plating layer is vertically upward. The protective film formed on such a structure can be a film having excellent crack-free covering properties. Thereby, it can be set as the electrochemical cell excellent in the reliability and mass-productivity of a cell.

  The electrochemical cell package according to the present invention is characterized in that the imaginary line A is inclined at 5 ° or more and 85 ° or less with respect to the outer bottom surface of the base container.

  According to the present invention, a taper is formed near the via wiring on the inner bottom surface of the base container. Thereby, the protective film in which the occurrence of cracks is suppressed can be formed.

  The electrochemical cell package according to the present invention is characterized in that an angle formed by the virtual line A and the virtual line B is 100 ° or more and 170 ° or less.

  According to the present invention, the tangent line where the plating layer and the inner bottom surface of the base container are in contact with each other is 100 ° to 170 ° open with respect to the inner bottom surface of the base container. Thereby, the protective film in which the occurrence of cracks is suppressed can be formed without depending on the presence or absence of the taper on the inner bottom surface of the base container.

  The electrochemical cell according to the present invention comprises an electrochemical cell package having the above-described characteristics, and a power generation element sealed in the electrochemical cell package and electrically connected to the through electrode. .

  By using the electrochemical cell according to the present invention, the electrolytic solution permeates from cracks generated in the protective film and the via wiring is not subject to anodic corrosion, so that the electrochemical cell having excellent reliability can be obtained.

  The method for manufacturing an electrochemical cell package according to the present invention is a method for manufacturing an electrochemical cell package in which a power generation element is housed and sealed inside a base container including an insulating base material, and the base material is a predetermined one. A step of processing into a shape, a step of forming a metal via wiring in the via hole of the base material, a step of forming a plating layer on the surface of the via wiring, and the via wiring having the plating layer formed thereon. Forming a conductive protective film that continuously covers the base material, and in a cross-sectional shape passing through the center of the via hole in which the via wiring is formed, the bottom of the base container and the plating layer Assuming a virtual line A, which is a tangent line passing through the bottom of the base container, and a virtual line B, which is a tangent line passing through the end of the plating layer, at the position where the ends contact, the virtual line A and the virtual line B Second-degree of the angle formed by When the line is a virtual line C, the base material, the via wiring, and the plating layer are formed so that the virtual line C faces vertically upward with an inclination exceeding 45 ° with respect to the outer bottom surface of the base container. It is characterized by that.

  By the production method of the present invention, a protective film having excellent coverage without cracks can be formed, and an electrochemical cell having excellent cell reliability and mass productivity can be produced.

  The method for manufacturing an electrochemical cell package according to the present invention is characterized in that the imaginary line A is inclined at 5 ° or more and 85 ° or less with respect to the outer bottom surface of the base container.

  By using the method for producing an electrochemical cell package according to the present invention, a protective film in which the generation of cracks is further suppressed can be produced.

  In the method for producing an electrochemical cell package according to the present invention, the substrate is made of a ceramic green sheet, and the ceramic green sheet is formed by punching to form a via hole and a taper around the via hole.

  By adopting the method for manufacturing an electrochemical cell package according to the present invention, the taper shape is made efficient so that the imaginary line C which is a bisector of the angle formed by the imaginary line A and the imaginary line B faces upward. Can be well formed. Thereby, the manufacturing method excellent in the mass-productivity of a cell can be provided.

  The method for manufacturing an electrochemical cell package according to the present invention is characterized in that an angle formed by the imaginary line A and the imaginary line B is not less than 100 ° and not more than 170 °.

  By using the method for manufacturing an electrochemical cell package according to the present invention, a protective film in which generation of cracks is suppressed can be formed.

  In the method for manufacturing an electrochemical cell package according to the present invention, the step of forming a plating layer on the surface of the via wiring includes electroless nickel plating on the through electrode using a plating bath containing an anisotropic growth promoter. It is characterized by applying electroless gold plating.

  By using the method for manufacturing an electrochemical cell package according to the present invention, it is possible to make the imaginary line C face vertically upward without forming a taper on the inner bottom surface of the base container. A suppressed protective film can be formed.

  According to the present invention, the reliability of an electrochemical cell can be improved by forming a protective film without cracks.

It is the schematic which shows the electrochemical cell of embodiment which concerns on this invention, and the package for electrochemical cells. It is sectional drawing which shows the outline | summary of the wiring structure of the package for electrochemical cells. It is a fragmentary sectional view which shows the detail of the package for electrochemical cells of embodiment which concerns on a prior art. It is a fragmentary sectional view which shows the detail of the package for electrochemical cells of embodiment which concerns on this invention. It is a fragmentary sectional view which shows the modification of the package for electrochemical cells of embodiment which concerns on this invention. It is a fragmentary sectional view which shows the modification of the package for electrochemical cells of embodiment which concerns on this invention. It is a fragmentary sectional view which shows the modification of the package for electrochemical cells of embodiment which concerns on this invention. It is a fragmentary sectional view which shows the modification of the package for electrochemical cells of embodiment which concerns on this invention. It is a fragmentary sectional view which shows the modification of the package for electrochemical cells of embodiment which concerns on this invention. It is the schematic which shows the manufacturing method of the package for electrochemical cells of embodiment which concerns on this invention.

  Hereinafter, embodiments of the electrochemical cell package of the present invention will be described, and each configuration will be described in detail with reference to the drawings.

In the present specification, the description of the positional relationship such as horizontal, vertical, etc., refers to the direction parallel to the outer bottom surface when the outer bottom surface of the base container constituting the electrochemical cell package described later is used as a reference surface. The vertical direction in the direction from the outer bottom surface to the sealing plate is expressed as vertical.
(Outline of packages for electrochemical cells)
The electrochemical cell package 1 of the present embodiment includes a base container 2 that houses a power generation element of the electrochemical cell, and a sealing plate 3 that hermetically closes the opening of the base container 2.

  As shown in FIG. 1, an electrochemical cell package 1 includes, as an example, a ceramic concave base container 2 and a flat metal sealing plate 3, and has a length of 3.2 mm × width of 2.5 mm × It can be a rectangular parallelepiped shape with a height of 1.0 mm. In addition to this, the package 1 for electrochemical cells can have various sizes and shapes in order to accommodate the power generation elements of the cell, such as a track shape or a cylindrical shape.

  A metal seal ring 9 is attached to the upper end of the concave base container 2 by brazing or the like, and after the power generation element is housed inside the base container 2, the seal ring 9 at the upper end of the base container 2 and the sealing plate 3, an electrochemical cell in which a power generation element is housed in the electrochemical cell package 1 in which the base container 2 and the sealing plate 3 are integrated is formed.

Although not shown, the power generation element is housed in the container as the electrochemical cell package 1 in which the ceramic base container 2 has a flat shape instead of a concave shape, and the metal sealing plate 3 has a reverse concave shape instead of a flat shape. It is good also as composition to do.
(Base container)
Next, the base container 2 in the electrochemical cell package 1 will be described in detail with reference to the drawings.

  FIG. 2 is a front cross-sectional view showing the configuration of the electrochemical cell package 1 and shows the AA cross section of FIG. The configuration shown in FIG. 2 is common to the prior art and the present embodiment except for the detailed shapes related to via wiring, plating layer, and protective film, which will be described later.

  The base container 2 is a box-shaped container having an opening at the top, and is a ceramic base composed of a rectangular bottom 2a and a rectangular frame-shaped wall 2b standing on the outer edge of the bottom 2a. Has material. In addition to the above-described size, the base container 2 can have a side of about 2 to 20 mm and a height of about 0.5 to 3 mm, for example, depending on the required characteristics of the cell.

  As shown in FIG. 2A, a connection terminal 4 is formed on the outer bottom surface of the base container 2 to be electrically connected to a circuit board or the like of a mounted device to be mounted. A plurality of connection terminals 4 are formed in order to electrically connect the positive electrode 10 and the negative electrode 11 which are the power generation elements of the cell.

  Further, as shown in FIG. 2A, a positive electrode wiring 5 and a negative electrode wiring 6 are formed in the base container 2 for electrical connection between the positive electrode 10 and the negative electrode 11 and the connection terminal 4, respectively. Specifically, the positive electrode wiring 5 is formed over the side surface and the inside of the bottom portion 2a of the base container 2, and the negative electrode wiring 6 is formed over the side surface of the bottom portion 2a and the wall portion 2b of the base container 2.

  A plating layer 7 composed of two layers of gold and nickel is formed on the exposed surfaces of the connection terminal 4, the positive electrode wiring 5, and the negative electrode wiring 6 in the base container 2. In particular, since the plating layer 7 is formed on the connection terminal 4, it is possible to maintain good bonding with the circuit board of the mounted device by soldering or the like.

  Furthermore, the upper part of the plating layer 7 formed on the exposed surface of the via wiring 5c among the positive electrode wiring 5 on the inner bottom surface of the base container 2 is for preventing corrosion of the positive electrode wiring 5 due to contact between the positive electrode wiring 5 and the electrolytic solution. A protective film 8 is formed. The protective film 8 is continuously formed over the upper part of the plating layer 7 and the inner bottom surface around it. Thereby, the exposed surface of the positive electrode wiring 5 and the plating layer 7 can be protected from contact with the electrolytic solution, and the electrical characteristics of the cell can be maintained.

  In addition, as a material which comprises the base material of the base container 2, the ceramic containing at least 1 sort (s) chosen from the group which consists of alumina, silicon nitride, zirconia, silicon carbide, aluminum nitride, mullite, and these composite materials is mentioned. However, the constituent material is not limited to this. Soda lime glass and heat-resistant glass can also be used. Since a long glass can be used as a material, in the case of a small package, a large number of pieces can be set for one glass, and cost reduction of the base member can be expected.

The base container 2 of the present embodiment is, for example, fired after bonding a ceramic green sheet corresponding to the wall 2b punched into a rectangular frame to a ceramic green sheet corresponding to the bottom 2a punched into a rectangular shape. It is formed by doing. A through hole can be formed by punching a hole in the ceramic green sheet corresponding to the bottom 2b in advance, and the via wiring 5c can be formed using the through hole.
(Connection terminals and wiring)
The connection terminal 4 shown in FIG. 2A is formed on the lower surface of the base container 2 so that the positive electrode side and the negative electrode side are paired. The connection terminals 4 are fixed to the substrate with cream solder or the like provided on the pattern of the mounting substrate by reflow processing or the like.

  In this embodiment, the connection terminal 4 can be formed by printing the electrode pattern by tungsten beforehand on the ceramic green sheet used as the base container 2, and baking the said ceramic green sheet. The connection terminal 4 has a structure in which the above-described plating layer 7 made of nickel and gold is formed on a tungsten pattern formed by a printing method.

  As shown in FIG. 2A, the positive electrode wiring 5 is connected to the connection terminal 4, passes through the side surface and the interlayer of the base container 2, and penetrates toward the inner bottom surface of the base container 2. Specifically, the wiring 5 is formed from the side wiring 5 a formed on the side surface of the base container 2, the interlayer wiring 5 b formed between the layers of the base container 2, and from the interlayer wiring 5 b to the inner bottom surface of the base container 2. Via wiring 5c. The interlayer wiring 5 b is formed between a plurality of ceramic green sheets that constitute the bottom 2 a of the base container 2. The via wiring 5c is formed in a cylindrical shape having an outer diameter of 0.1 to 0.5 mm, for example, in accordance with the shape of the via hole formed in the ceramic green sheet.

  The interlayer wiring 5b and the via wiring 5c may be divided into a plurality of lines inside the base container 2. As a result, even if anode corrosion occurs due to the contact of the electrolyte with one of the via wirings 5c, the electrical characteristics can be maintained without affecting the other via wirings 5c and the interlayer wirings 5b.

  In addition to the structure shown in FIG. 2 (a), the positive electrode wiring 5 is connected to the via wiring so as to penetrate directly from the connection terminal 4 toward the inner bottom surface of the base container 2, as shown in FIG. 2 (b). You may be comprised only by 5c. Further, the negative electrode wiring 6 is formed on the side surface of the base container 2, and as shown in FIG. 2C, the via wiring extends from the connection terminal 4 to the inner bottom surface of the base container 2, as in the positive electrode wiring 5. It may have a structure penetrating toward it. The shape shown in FIG. 2C has a configuration in which protective films 8 for the positive electrode side and the negative electrode side are formed on the inner bottom surface of the base container 2. When the power generation element of the electrochemical cell has a shape formed by, for example, winding and laminating the electrode body composed of a positive electrode and a negative electrode coated on a current collector made of aluminum foil, with a separator interposed therebetween Such a container shape can be used.

The positive electrode wiring 5 and the negative electrode wiring 6 are made of a valve metal having a high melting point such as tungsten or molybdenum. These materials can be integrally sintered with the ceramic green sheet when the base container 2 is manufactured. Specifically, a conductive paste made of these metals and resin is applied to the surface of the ceramic green sheet by screen printing or the like, and the via wiring is formed by filling the through hole with the paste, and then firing is performed. As a result, the base container 2 in which the positive electrode wiring 5 and the negative electrode wiring 6 are formed can be manufactured.
(Seal ring)
As shown in FIG. 2A, the seal ring 9 has a square frame-shaped cross section that matches the shape of the upper end surface of the wall portion 2b of the base container 2, and a brazing material is provided on the upper end surface of the wall portion 2b. It is joined via. The seal ring 9 can be made of a material having a thermal expansion coefficient close to that of ceramic, for example, Kovar (trade name of Westinghouse), which is an iron / cobalt / nickel alloy. The brazing material is made of an Ag—Cu alloy, an Au—Cu alloy, or the like.
(Sealing plate)
As shown in FIG. 1, the sealing plate 3 is joined to the upper surface of the seal ring 9 and seals the base container 2. The sealing plate 3 is made of a nickel-plated alloy such as Kovar or 42 alloy that has a thermal expansion coefficient close to that of ceramic. More specifically, a thin plate made of Kovar having a thickness of about 0.1 mm to 0.2 mm and having a surface subjected to electrolytic nickel plating or electroless nickel plating with a thickness of about 2 μm to 4 μm is used. The sealing plate 3 using such a material can be welded to the seal ring 9 by, for example, resistance seam welding, laser seam welding, or the like, and the airtightness inside the base container 2 in a closed state can be improved. The base container 2 is hermetically closed by the sealing plate 3.
(Protective film)
The protective film 8 in the present embodiment is a film made of a conductive material disposed on the inner bottom surface of the base container 2. This protective film 8 prevents direct contact between the upper end portion of the via wiring 5c of the positive electrode wiring 5 and the plating layer 7 formed on the upper portion thereof, and the electrolytic solution of the cell, and the power generation element of the cell. It is formed to electrically connect the positive electrode wiring 5.

  The protective film 8 is a film made of at least one type of valve metal selected from aluminum, zinc, an alloy containing these metals as a main component, gold, stainless steel, titanium, or the like, and is a material that is difficult to dissolve in the electrolyte. Consists of. In particular, as aluminum, a pure aluminum system, an Al—Cu system alloy, an Al—Mn system alloy, an Al—Mg system alloy, or the like defined by JIS can be used. These protective films 8 can be formed by methods such as vapor deposition, sputtering, thermal spraying, and paste application.

The thickness of the protective film 8 is desirably 5 μm or more and 100 μm or less. The range of 10 μm or more and 30 μm is more desirable. When the film thickness is thin, fine porous existing inside the film is connected, and the electrolytic solution 7 penetrates into the tungsten via wiring 5c under the protective film 8 and easily causes electrolytic corrosion of tungsten. In addition, when the thickness is large, it takes a long time to form the protective film 8, so that there is a problem that the mass productivity is poor in manufacturing. If it is the range of the thickness of said protective film 8, it can be set as the protective film excellent in coating | coverability by combining with the shape of the plating layer 7 mentioned later and the inner bottom face of the base container 2, and it was set as the electrochemical cell. In this case, mass productivity and reliability can be improved.
(Plating layer)
Next, the plating layer 7 in this embodiment will be described in detail with reference to FIGS. In addition, the relationship between the shape of the inner bottom surface of the base container 2 and the plating layer 7 and the protective film 8 will be described.

  3 and 4 are detailed sectional views showing the vicinity of the via wiring 5c of the base container 2 showing the conventional example and the present embodiment, respectively, and pass through the center of the cylindrical via wiring 5c formed in the base container 2. FIG. A cross section is shown.

  As described above, in the present embodiment, the plating layer 7 is formed on a portion of the connection terminal 4, the positive electrode wiring 5, and the negative electrode wiring 6 that are formed on the base container 2 and exposed on the surface of the base container 2. The plating layer 7 is formed by sequentially laminating a nickel plating layer 7a and a gold plating layer 7b on an exposed portion of a metal such as tungsten by electrolytic plating or electroless plating.

  FIG. 3A shows the coating shapes of the plating layer 7 and the protective film 8 in the configuration of the conventional base container 2. The plating process is usually an isotropic process, and the plating layer 7 is uniformly formed on the surface of the via wiring 5 c on the inner bottom surface of the base container 2. At this time, the end surface of the plating layer 7 is in contact with the inner bottom surface of the base container 2 perpendicularly to the inner bottom surface.

  Here, when a cross section passing through the center of the via hole as shown in FIG. 3A is considered, a line corresponding to the inner bottom surface of the base container 2 made of ceramics is defined as a virtual line A. In the prior art, since the inner bottom surface of the base container 2 is horizontal even in the vicinity of the via wiring 5c, the virtual line A is horizontal. In addition, the plated layer 7 in which nickel (Ni) and gold (Au) are sequentially laminated on the tungsten (W) constituting the via wiring 5c is shown in a cross-sectional view at the end in contact with the inner bottom surface of the base container 2. A tangent line including the end is defined as a virtual line B. A bisector of an angle formed by the virtual line A and the virtual line B is defined as a virtual line C.

  In the prior art as shown in FIG. 3A, since the end surface of the plating layer 7 is in contact with the inner bottom surface of the base container 2 perpendicularly to the inner bottom surface, the virtual line A and the virtual line B are formed. The angle is 90 °. The inclination angle (θc) from the horizontal direction of the virtual line C, which is a bisector of the angle formed by the virtual line A and the virtual line B, is 45 °.

  A process of forming the protective film 8 on the plating layer 7 in the conventional technique will be described with reference to FIG. A protective film 8 made of aluminum or the like is formed on the plating layer 7 by vapor deposition or sputtering. In these film forming methods, metal atoms constituting the protective film 8 are incident on and deposited on the inner bottom surface of the base container 2 and the plating layer 7 to form a film. As for the incident distribution of metal atoms, vertical incidence is maximum with respect to the base container 2, but oblique incidence also exists.

  In the configuration of the base container 2 and the plating layer 7 as shown in FIG. 3A, normal incident atoms are hard to be deposited on the side surfaces of the plating layer 7, and the protective film 8 is formed by depositing atoms by oblique incidence. . Accordingly, the vertical deposition rate is larger in the horizontal deposition rate and the vertical deposition rate. Since the deposition rate in the horizontal direction tends to be higher at the upper part of the film, the protective film 8 formed on the surface of the plating layer 7 has an overhang shape as shown in FIG. At this time, since the incidence of metal atoms on the lower side of the side surface is hindered by the overhang shape (shadowing effect), the coating deposited on the side surface of the plating layer 7 and the coating deposited on the inner bottom surface of the base container 2 Cracks occur between them. When cracks occur, the electrolyte enters the inside of the protective film 8, and the nickel in the plating layer 7 and tungsten in the via wiring 5 c come into contact with the electrolyte, so that they are corroded and eluted. Stops functioning.

  On the other hand, as shown in FIG. 4, in the present embodiment, the inner bottom surface of the base container 2 is formed in a taper shape around the via wiring 5c. In such a shape, even if the end surface of the plating layer 7 is in contact with the inner bottom surface of the base container 2 perpendicularly, the plating layer 7 has an inclination greater than the vertical in the horizontal direction. The protective film 8 on the surface becomes difficult to be overhanged. Thereby, the protective film 8 formed from the inner bottom surface of the base container 2 to the surface of the plating layer 7 is uniformly formed, and cracks are less likely to occur.

  Expressed more quantitatively, the virtual line A in FIG. 4 has an inclination angle θa with respect to the horizontal direction by the inclination of the taper shape. Further, the imaginary line B that is a tangent to the end of the plated layer 7 has an inclination angle θb with respect to the horizontal direction. A virtual line C that is a bisector of an angle formed by the virtual line A and the virtual line B has an inclination angle θc with respect to the horizontal direction.

  These inclination angles θa, θb, and θc start from the intersection of the virtual line A and the virtual line B with respect to the via wiring 5c in the horizontal direction.

  In the present embodiment, the imaginary line C that is a bisector of the angle formed by the imaginary line A and the imaginary line B is closer to the vertical direction than the conventional configuration as shown in FIG. With such an inclination angle θc, the vertically incident atoms have a large contribution to the film deposition, making it difficult to form an overhang shape, and the protective film 8 is formed uniformly.

  In particular, when the inclination angle θc is further increased, the protective film 8 becomes a more uniform film over the inner bottom surface of the base container 2 and the plating layer 7. Such an inclination angle θc is preferably 50 ° or more, and particularly preferably 60 ° or more.

  Specifically, as shown in FIG. 4, even when a tapered shape is formed on the inner bottom surface of the base container 2, the end surface of the isotropically deposited plating layer 7 is formed perpendicular to the tapered shape. Is done. Therefore, the inclination angle θb of the tangent to the plating end surface is θb = 90 ° + θa with respect to the taper-shaped inclination angle θa. Therefore, since the inclination angle θc is a bisector of the angle formed by the virtual line A and the virtual line B, θc = (θa + θb) / 2 = θa + 45 °. When the taper is formed on the inner bottom surface of the base container 2 so that the inclination angle θa is 5 ° or more, the occurrence of an overhang shape is further suppressed when the protective film 8 is formed, which is more preferable.

As the inclination angle θa is larger than 5 °, the inclination angle θc correspondingly increases, and when θa is 45 °, θc is vertically upward. When θa is further increased, θc is again inclined from vertically above. When θa becomes larger than 85 °, θc becomes larger than 130 ° (the inclination from the horizontal on the via wiring 5c side becomes less than 50 °), so that the effect of the present invention is poor. In addition, at such θa, since the taper to be formed approaches to the vertical, there arises a problem that it becomes difficult to process the ceramic green sheet by the method described later. For this reason, it is preferable that the inclination angle θa is at most 85 ° or less.
(Modification 1)
Next, a modification in the present embodiment will be described with reference to FIG.

  In the above embodiment, by forming a taper on the inner bottom surface of the base container 2 by the inclination angle θa, the imaginary line C that is a bisector of the imaginary line A and the imaginary line B is shaped so as to face vertically upward. The protective film 8 made of aluminum is formed satisfactorily.

  On the other hand, instead of the configuration as in the above-described embodiment in which the container is tapered as in the present modification, the direction of the imaginary line C is made vertically upward also by making the contact angle of the plating layer 7 gentle. Can do. Thereby, even if it does not change the shape of the ceramic part of the base container 2, since the effect of this invention is produced, this invention can be implement | achieved at low cost and it is preferable.

  Here, the case where the virtual line A is horizontal as shown in FIG. 5 will be described first. When the plating layer 7 is isotropically formed on the inner bottom surface of the base container 2, the end surface of the plating layer 7 is formed perpendicular to the inner bottom surface of the base container 2. Is 90 °. In this case, the inclination angle θb of the virtual line B with respect to the horizontal direction is 90 °. On the other hand, when the plating layer 7 is formed gently with respect to the inner bottom surface of the base container 2 as in this modification, the angle formed by the imaginary line A and the imaginary line B is greater than 90 ° (θb Is also greater than 90 °). Accordingly, the imaginary line C, which is a bisector of the angle formed by the imaginary line A and the imaginary line B, is configured to face vertically upward such that the inclination angle θc is larger than 45 °.

  Also in this modified example 1, as in the above-described embodiment, the occurrence of an overhang shape is suppressed when the protective film 8 is formed, so that the generation of cracks in the protective film 8 can be suppressed. In particular, if the angle formed by the imaginary line A and the imaginary line B (in this case, the inclination angle θb) is 100 ° or more, the occurrence of cracks in the protective film 8 can be more effectively suppressed, which is more preferable. It is an aspect.

  On the other hand, if the contact angle of the plating layer 7 becomes too large, the thickness of the plating body becomes thin, and there is a possibility that the bondability with the circuit board will deteriorate. For this reason, it is preferable that at least the angle formed by the virtual line A and the virtual line B (in this case, the inclination angle θb) is smaller than 170 °.

  In order to smoothen the contact angle of the plating layer 7 in this way, for example, by using an electroless plating, the spread of the plating layer 7 can be adjusted by adding an anisotropic growth promoter to the plating bath. . When such a plating bath is used, the plating layer 7 can be grown in an anisotropically spread state.

  As the anisotropic growth promoter, for example, various compounds such as metal ions such as lead, bismuth, tellurium, and copper ions, nitrogen compounds, polyethylene glycol, acetylene glycol, and acetylene carboxylic acid can be used.

Further, although not shown, by combining the formation of the tapered shape on the inner bottom surface of the base container 2 as in the above-described embodiment and the anisotropic growth of the plating layer 7 as in this modification, the virtual line A and The angle formed with the imaginary line B can be made larger than 90 °, and the tapered shape of the inner bottom surface is added so that the imaginary line C faces vertically upward. In particular, if the angle formed by the imaginary line A and the imaginary line B is 100 ° or more and 170 ° or less, the protective film 8 can be formed more gently and cracking can be prevented more reliably. This is a more preferred embodiment. The angle formed by the virtual line A and the virtual line B after the inclination angle θa of the virtual line A from the horizontal direction is 5 ° or more and the inclination angle θa of the virtual line A is 5 ° or more and 85 ° or less. Is preferably 100 ° or more and 170 ° or less because the protective film 8 can be formed more gently.
(Modification 2)
In the above embodiment, the via wiring 5c is formed at the position of the via hole of the base container 2 as shown in FIG. On the other hand, as shown in FIG. 6, the via wiring 5 c may protrude to the outside of the via hole, and the end of the via wiring 5 c may come to the taper position of the base container 2.

  In this way, if the shape is as shown in FIG. 6, the end of the plating layer 7 formed on the upper portion of the via wiring 5c is in a tapered position as in the embodiment shown in FIG. By tilting A from the horizontal direction, it is possible to bring the virtual line C closer to the vertical direction so that the tilt angle θc of the virtual line C is larger than 45 °. In this case, the inclination angle θa of the virtual line A is preferably 5 ° or more and 85 ° or less.

  Since the protective film 8 formed on such a structure can be made into a film having excellent crack-free covering properties, an electrochemical cell having excellent cell reliability and mass productivity can be obtained. In addition, since the difference in height between the flat portion of the inner bottom surface of the base container 2 and the via wiring 5c can be made smaller than the embodiment shown in FIG. 4, the flatness of the protective film 8 can be further improved. Can do.

In addition to such a structure of the base container 2, the angle formed by the imaginary line A and the imaginary line B is set to 100 ° or more and 170 ° or less by using the plating layer anisotropically grown as described above. Further, the flatness of the protective film 8 can be improved.
(Modification 3)
Further, the shape of the inner bottom surface of the base container 2 in the vicinity of the via wiring 5c may be other than the taper. For example, it may have a cross-sectional R shape as shown in FIGS. Further, the end of the taper may be chamfered or rounded. In the case of such a shape, the virtual line A is a tangent to the inner bottom surface of the base container 2 at the position of the end surface of the plating layer 7. Then, the virtual line C can be made to approach vertically upward so that the inclination angle θc of the virtual line C becomes larger than 45 ° by tilting the virtual line A from the horizontal direction. In this case, the inclination angle θa of the virtual line A is preferably 5 ° or more and 85 ° or less.

  Since the protective film 8 formed on such a structure can be made into a film having excellent crack-free covering properties, an electrochemical cell having excellent cell reliability and mass productivity can be obtained. In addition, since the vicinity of the via hole of the base container 2 does not have an acute angle portion due to the R shape, chamfering, or the like, the flatness of the protective film 8 can be further improved.

In addition to such a structure of the base container 2, the angle formed by the imaginary line A and the imaginary line B is set to 100 ° or more and 170 ° or less by using the plating layer anisotropically grown as described above. Further, the flatness of the protective film 8 can be improved.
(Modification 4)
Further, as shown in FIG. 9, the inner bottom surface shape of the base container 2 can be formed such that the periphery of the via wiring 5c is formed horizontally, and the periphery thereof is formed into a taper, an R shape, or the like. In this case, similarly to the above-described embodiment and each modification, the virtual line C is vertically upward so that the virtual line A is inclined from the horizontal direction so that the inclination angle θc of the virtual line C is larger than 45 °. You can get closer. In this case, the inclination angle θa of the virtual line A is preferably 5 ° or more and 85 ° or less.

  Since the protective film 8 formed on such a structure can be made into a film having excellent crack-free covering properties, an electrochemical cell having excellent cell reliability and mass productivity can be obtained. In addition to this, by flattening the periphery of the via wiring 5c, it becomes easy to form the via wiring 5c only in the via hole portion of the ceramic green sheet. As a result, the via wiring 5c can be further protected from the electrolytic solution, and mass productivity and reliability can be further improved in the case of an electrochemical cell.

In addition to such a structure of the base container 2, the angle formed by the imaginary line A and the imaginary line B is set to 100 ° or more and 170 ° or less by using the plating layer anisotropically grown as described above. Further, the flatness of the protective film 8 can be improved.
(Outline of manufacturing method for electrochemical cell package)
Next, a method for manufacturing the electrochemical cell package 1 of the present embodiment will be described below.

  The manufacturing method of the electrochemical cell package 1 according to the present invention includes a method of manufacturing the base container 2 constituting the electrochemical cell package 1 and a method of manufacturing the sealing plate 3.

  The method of manufacturing the base container 2 includes a green sheet processing step for processing a ceramic green sheet into a predetermined shape, a paste forming step for forming a metal paste to be a wiring on the ceramic green sheet, and a plurality of metal paste formed Sintering process in which ceramic green sheets are combined and sintered together, plating layer forming process for plating the surface of the wiring, seal ring forming process by brazing, etc., protection by vapor deposition, sputtering, etc. A protective film forming step for forming a film.

Moreover, the method of manufacturing the sealing plate 3 includes a step of producing a metal plate as a raw material and a step of punching out the plate with a press. Moreover, when manufacturing the sealing board of shapes other than a flat plate as needed, it can press-process a board | plate material and the sealing board after stamping. Furthermore, you may form a plating layer by giving nickel plating etc. to the formed sealing board 3 as needed.
(Base container manufacturing method)
Here, the manufacturing method of the base container 2 of this embodiment is explained in full detail based on FIG.

  First, the green sheet processing step will be described. A plate-shaped ceramic green sheet and a frame-shaped ceramic green sheet are respectively formed so as to correspond to the bottom 2a and the wall 2b, which are base materials constituting the concave base container 2 in the present embodiment.

  The frame-shaped green sheet constituting the wall portion 2b is formed into a rectangular frame shape by forming a flat green sheet and then opening it with a rectangular punch so as to correspond to the inner dimensions of the concave base container 2. A ceramic green sheet is prepared.

  Further, a flat ceramic green sheet constituting the bottom portion 2a as shown in FIG. 10A is punched and opened in the thickness direction using a punch. Thereby, the bottom 2a in which the via hole is formed as shown in FIG. 10B can be formed.

  Then, a via wiring 5c as shown in FIG. 10C is formed by filling the via hole formed in the bottom 2a with a metal paste in which a resin or the like is mixed with a high melting point metal such as tungsten or molybdenum. can do. Also, by applying these metal pastes on a ceramic green sheet by a screen printing method or the like, a paste pattern that becomes the connection terminals 4, the side wirings 5a, and the interlayer wirings 5b formed on the bottom 2a and the wall 2b. Can be formed on a ceramic green sheet.

  In the present embodiment, as shown in FIG. 10D, the mold 12 is pressed against the ceramic green sheet on which the via wiring 5c is formed, as shown in FIG. 10E. A taper shape can be formed around the via wiring and the periphery thereof. The mold 12 includes a flat portion 12a facing the via wiring 5c and a taper forming portion 12b corresponding to the taper formed on the ceramic green sheet.

  In this embodiment, as shown in FIGS. 10B to 10E, a taper is formed on the ceramic green sheet on which the via wiring 5c is formed. However, the formation of the via hole as shown in FIG. Via wire 5c may be formed by press-contacting mold 12 to the formed ceramic green sheet to form a taper and then filling with a metal paste. When the taper is formed on the ceramic green sheet on which the via wiring 5c is formed by the processes as shown in FIGS. 10B to 10E, after the paste is embedded in the via hole by screen printing or an embedding method, the area around the via hole is unnecessary. This is a preferred embodiment because it can efficiently remove a paste.

  Next, the sintering process will be described. After the ceramic green sheets on which these metal pastes are formed are laminated in the order of the green sheet constituting the bottom part and the green sheet constituting the frame part, the container and the wiring can be integrally formed by sintering. The sintering temperature can be set to 1500 ° C., for example.

  Next, the plating layer forming process will be described. By applying nickel plating and then gold plating to the sintered green sheet on which the wiring is formed, as shown in FIG. 10 (f), on the surface of the wiring portion such as tungsten or molybdenum exposed on the surface of the ceramic, A plating layer 7 composed of a nickel plating layer 7a and a gold plating layer 7b is formed. The plating layer 7 can be formed by performing electrolytic plating or electroless plating.

  In particular, as described in Modification 1 above, in the plating layer forming step, a plating layer comprising a nickel plating layer 7a and a gold plating layer 7b by electroless plating using a plating bath containing an anisotropic growth promoter. 7 can be formed. Thereby, the contact angle of the plating layer 7 can be made smooth on the inner bottom surface of the base container 2, and the occurrence of cracks can be suppressed.

  And a protective film formation process is demonstrated. The protective film 8 is a film made of a chemically stable valve metal such as aluminum or titanium, and is made of a material that is difficult to dissolve in the electrolytic solution. This protective film can be formed, for example, by vapor deposition, ion plating, sputtering, or the like. When these methods are used, the film can be formed as follows. First, a mask made of metal or the like having openings formed therein is prepared and housed in a chamber of a film forming apparatus and evacuated to a predetermined degree of vacuum by a vacuum exhaust system, and then a valve metal material is deposited or a valve is formed. A target made of a metal material is physically hit with ions to fly the valve metal material, and a film is formed on the inner bottom surface of the base container. In these film forming methods, since the film forming conditions are easily controlled, a high-density film having a low resistivity and a low liquid penetration property can be formed.

  The aluminum film can also be formed by screen printing. A technique has been developed that can form a wiring pattern at a temperature of 150 ° C. or lower even for aluminum that is easily oxidized at a high temperature. Since this method is a printing method, a thicker film can be formed and a thick film of several tens of μm can be easily obtained as compared with a thin film forming technique such as a vapor deposition method. Further, the aluminum film can be produced by electroplating. Using a plating solution composed of dimethylsulfone and aluminum chloride, a film having a smooth surface and a uniform inside can be obtained.

In this way, as shown in FIG. 10G, the generation of cracks is suppressed, and the protective film 8 formed uniformly can be formed.
(Electrochemical cell)
The electrochemical cell in which the power generation element and the electrolytic solution are accommodated in the electrochemical cell package 1 of the present invention is, for example, a nonaqueous electrolyte secondary battery or an electric double layer capacitor depending on the configuration of the accommodated electrodes and electrolytic solution. It can be set as various electrical storage devices, such as a lithium ion capacitor.

  Moreover, the structure of a power generation element can be made into the structure which a pair of positive electrode and negative electrode oppose via a separator as shown to Fig.2 (a). In addition, although not shown in the drawing, a configuration in which an electrode sheet composed of a pair of positive and negative electrodes coated on a metal foil is wound facing each other through a separator, or a laminated electrode in which electrode sheets are laminated in multiple layers through a separator. A structure in which a lead attached to the configuration and a protective film (pad film) formed on the inner bottom surface of the base container 2 are joined may be employed.

  These electrochemical cells can obtain various electrical characteristics depending on the configuration of the power generation element and the electrolytic solution, and are applied to, for example, a backup power source for a small device or a power source for smoothing a circuit voltage. be able to.

DESCRIPTION OF SYMBOLS 1 ... Electrochemical cell package 2 ... Base container 2a ... Bottom part 2b ... Side part 3 ... Sealing plate 4 ... Connection terminal 5 ... Positive electrode wiring 5a ... Side part Wiring 5b ... Interlayer wiring 5c ... Via wiring 6 ... Negative electrode wiring 7 ... Plating layer 7a ... Nickel plating layer 7b ... Gold plating layer 8 ... Protective film 9 ... Seal ring 10 ... Positive electrode 11 ... Negative electrode

Claims (9)

A package for an electrochemical cell that houses and seals a power generation element inside a base container including an insulating base material,
A metal via wiring having a surface on the inner side of the base container is formed at the bottom of the base container,
A plating layer is formed on the surface of the via wiring, and further, a conductive protective film that continuously covers the via wiring on which the plating layer is formed and the bottom is formed,
In a cross-sectional shape passing through the center of the via hole in which the via wiring is formed, a virtual line A that is a tangent passing through the bottom of the base container at a position where the bottom of the base container and the end of the plating layer are in contact with each other, Assuming a virtual line B that is a tangent line passing through the end of the plated layer, and assuming that the bisector of the angle formed by the virtual line A and the virtual line B is a virtual line C, the virtual line C is An electrochemical cell package characterized by being directed vertically upward so as to be inclined at an angle of more than 45 ° with respect to the outer bottom surface of the base container.   2. The electrochemical cell package according to claim 1, wherein the imaginary line A is inclined by 5 ° or more and 85 ° or less with respect to the outer bottom surface of the base container.   The package for an electrochemical cell according to claim 1 or 2, wherein an angle formed by the virtual line A and the virtual line B is 100 ° or more and 170 ° or less.   4. An electric cell comprising: the electrochemical cell package according to claim 1; and an electric power generation element sealed in the electrochemical cell package and electrically connected to the through electrode. Chemical cell. A method for manufacturing a package for an electrochemical cell that encloses and seals a power generation element inside a base container including an insulating base material,
The step of processing the base material into a predetermined shape, the step of forming a metal via wiring in the via hole of the base material, the step of forming a plating layer on the surface of the via wiring, and the formation of the plating layer Forming a conductive protective film that continuously covers the via wiring and the base material,
In a cross-sectional shape passing through the center of the via hole in which the via wiring is formed, a virtual line A that is a tangent passing through the bottom of the base container at a position where the bottom of the base container and the end of the plating layer are in contact with each other, Assuming a virtual line B that is a tangent line passing through the end of the plated layer, and assuming that the bisector of the angle formed by the virtual line A and the virtual line B is a virtual line C, the virtual line C is A method for manufacturing a package for an electrochemical cell, wherein the base material, the via wiring, and the plating layer are formed so as to face vertically upward with an inclination exceeding 45 ° with respect to an outer bottom surface of a base container.   6. The method for manufacturing a package for an electrochemical cell according to claim 5, wherein the imaginary line A is inclined by 5 ° or more and 85 ° or less with respect to the outer bottom surface of the base container. The substrate is made of a ceramic green sheet,
The method for producing an electrochemical cell package according to claim 5 or 6, wherein the ceramic green sheet is formed by punching to form a via hole and a taper around the via hole.   The method for producing an electrochemical cell package according to any one of claims 5 to 7, wherein an angle formed by the imaginary line A and the imaginary line B is not less than 100 ° and not more than 170 °.   6. The step of forming a plating layer on the surface of the via wiring includes performing electroless nickel plating and electroless gold plating on the through electrode using a plating bath containing an anisotropic growth accelerator. The manufacturing method of the package for electrochemical cells as described in any one of 1-8.

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