JP2009076846A - Electrochemical cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coin-type electrochemical cell that stably supports a cell during mounting by solder reflow. <P>SOLUTION: An upper terminal of an electrochemical cell includes a first part, which is bonded to an electrode on the upper-face side and expands toward the edge part of the upper face of a cell body, a plurality of second parts downwardly extending from the first part, and a plurality of third parts that are bent from each of the lower ends of a plurality of the second parts and extend toward a radial direction of the cell body. Projections of the upper and lower terminals onto a plane including the lower face of the cell body are almost stored in a square circumscribing a projection of the cell body onto the plane. Projections of a plurality of the second parts onto the plane are arranged near two or more corners of the square. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrochemical cell having terminals suitable for surface mounting on a substrate.

At present, electrochemical cells such as lithium batteries and electric double layer capacitors are widely used in portable electronic devices and the like. Among these, as disclosed in Patent Document 1, many small electrochemical cells used for applications such as a backup power source for portable electronic devices have a coin-shaped main body. In the case of a coin-shaped electrochemical cell, one of the upper and lower surfaces of the cell body is a positive electrode and the other is a negative electrode.
JP 2006-344534

  Many of such electrochemical cells have terminals (lead wires) for mounting on a substrate. The terminal is a sheet metal member generally made of steel or the like, and one end is joined to the upper and lower surfaces of the cell body. This joining is performed by spot welding, for example. In the configuration of Patent Document 1, the terminal joined to the upper surface of the cell body wraps around the side surface of the cell body, and the other end is arranged on the same plane as the other end of the terminal joined to the lower surface. Also, cream solder is applied to the lower surface of the other end of both terminals or the portion of the substrate that contacts the lower surface of the other end of both terminals. Therefore, by placing the electrochemical cell on the substrate so that the lower surface of the cell body faces the substrate and heating the substrate in a furnace, the solder melts and the substrate and the other ends of both terminals are joined. (Surface mounting by solder reflow).

  However, in the above configuration, when the electrochemical cell is mounted, the solder fixing one of the terminals may be melted first due to the non-uniform temperature distribution in the furnace. Then, the support state of the cell main body by both terminals becomes unbalanced, and the electrochemical cell may not be correctly mounted because the cell main body is inclined and directly contacts the substrate. This problem is particularly noticeable in the case of using lead-free solder having a high melting point, which is frequently used for environmental reasons in recent years.

  Further, if the substrate is warped, the inclination with respect to the substrate differs between the tip portion of the upper terminal (the portion in contact with the substrate) and the tip portion of the lower terminal. In such a state, either the tip of the upper terminal or the tip of the lower terminal, or the lower surfaces of both are inclined with respect to the substrate. In this case, the contact area between the substrate and the terminal cannot be sufficiently obtained, and there is a possibility that a solder joint failure occurs.

  The present invention has been made to solve the above problems. That is, an object of the present invention is to provide an electrochemical cell in which a cell body is stably supported during mounting by solder reflow. It is another object of the present invention to provide an electrochemical cell capable of sufficiently increasing the contact area between a terminal and a substrate even when the substrate is warped.

  In order to achieve the above object, the electrochemical cell of the present invention includes a first portion in which the upper terminal is joined to the electrode on the upper surface side and extends toward the edge of the upper surface of the cell body, and a lower portion from the first portion A plurality of second portions extending toward the cell, and a plurality of third portions bent from the lower ends of the plurality of second portions and extending in the radial direction of the cell body, The projections of the upper and lower terminals on the plane including the plane are substantially stored in a square circumscribing the projection of the cell body on the plane, and projections of the plurality of second portions onto the plane are two or more corners of the square. It is arranged in the vicinity of

  Thus, in the configuration of the present invention, the upper terminal branches into two, and the cell can be supported at each of the branched ends. That is, since the cell can be supported at at least three points together with the lower terminal, the cell can be stably supported on the substrate.

  For example, at least two of the projections of the plurality of second portions onto the plane are respectively disposed at two adjacent corners of the square. Further, when there are two corners where the projection of the second part on the plane is not arranged (that is, the projection of the second part is arranged only at two adjacent corners of the square), the second It is preferable that the projection on the plane of the lower terminal is arranged substantially adjacent to the side of the square with the two corners as both ends where the projection of the portion is not arranged on the plane. With such a configuration, since the center of the disk of the cell body (that is, the center of gravity of the cell) is surrounded by the pair of third portions of the upper terminal and the lower terminal, the cell body of the electrochemical cell is more It is supported stably.

  Preferably, the shape of the first portion of the upper terminal is V-shaped with both ends connected to the second portion. With such a configuration, when the upper terminals are manufactured from the metal plate by punching, more upper terminals can be obtained from one plate.

  Alternatively, projections of the plurality of second parts onto the plane are arranged at two corners of the square, and projections of the second part onto the other two corners of the square are arranged. Not.

  The lower terminal has an elongated shape, the lower terminal is joined to the lower surface of the cell body at a substantially central portion in the major axis direction of the lower terminal, and both ends in the major axis direction of the lower terminal are respectively second. It is preferable that the projections of the portions are arranged at the two corners of the square where the projections are not arranged. With such a configuration, the tips of the upper terminal and the lower terminal are arranged at the four corners of the square, and the cell body can be stably supported by the upper and lower terminals.

  It is preferable that right-angle portions are formed at both ends of the lower terminal in the long axis direction, and the projection of the right-angle portions onto the plane is configured so as to follow the corresponding corners of the square. With such a configuration, it is possible to increase the size of the portion of the projection of the lower terminal that protrudes from the projection of the cell body within the range in which the lower terminal does not protrude from the square. For this reason, after the surface mounting heat treatment is finished, an ultrasonic probe or the like is pressed from the upper side of the cell body against the portion of the lower terminal protruding from the cell body to easily check whether soldering has been performed. be able to. Moreover, since the solder surface can be made large by this configuration, it is possible to prevent the occurrence of soldering defects.

  The third portion is preferably configured to extend radially outward of the cell body from the lower end of the second portion. With such a configuration, after the surface mounting heat treatment is completed, it is easy to inspect whether soldering has been performed by pressing an ultrasonic probe or the like from the upper side of the cell body against the third portion of the upper terminal. Can be done.

  The third portion of the upper terminal has a substantially right triangle shape. If the upper terminal is arranged so that the projection of the right angle portion of the third portion on the plane is along the corner of the square, This portion is arranged in a corner of a square which is a dead space that is inevitably generated when the capacitor is mounted on the substrate. For this reason, the cell body can be stably supported without increasing the space on the substrate occupied by the capacitor.

  Preferably, at least a part of the second portion of the upper terminal is bent so as to protrude outward or inward in the radial direction of the cell body so that the second portion can bend in the vertical direction. At least one bent portion. With such a configuration, even if the inclination and height of the substrate are different between the upper terminal side and the lower terminal side due to warpage of the substrate, the upper terminal depends on the state of the surface of the substrate. Can be mounted reliably by bending and solder reflow.

  In order to achieve the above object, the electrochemical cell of the present invention has a first portion in which an upper terminal is joined to an electrode on the upper surface side and extends toward an edge of the upper surface of the cell body, A second portion extending downward from the second portion and a third portion extending radially outward of the cell body from the lower end of the second portion, and the second portion of the upper terminal is The second portion has at least one bent portion that is bent so as to protrude outward or inward in the radial direction of the cell body so that the second portion can be bent in the vertical direction.

  With such a configuration, even if the inclination and height of the substrate are different between the upper terminal side and the lower terminal side due to warpage of the substrate, the upper terminal depends on the state of the surface of the substrate. Can be mounted reliably by bending and solder reflow.

  Preferably, the second portion of the upper terminal is provided with a plurality of bent portions arranged in the vertical direction, and the protruding directions of any two bent portions continuous in the vertical direction are different from each other. That is, according to this configuration, the second portion is more easily bent by the plurality of bent portions.

  The second portion of the upper terminal is formed in an S shape in which one of the upper side and the lower side protrudes radially outward of the cell body and the other protrudes radially inward of the cell body. The Here, the bent portion may be formed by bending the upper terminal, or may be formed by curling the upper terminal.

  As described above, according to the present invention, an electrochemical cell that can stably support the cell body at the time of mounting by solder reflow is realized. In addition, according to the present invention, an electrochemical cell is realized in which the contact area between the terminal and the substrate can be made sufficiently large even when the substrate is warped.

  Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a top view and a bottom view, respectively, of an electric double layer capacitor that is an electrochemical cell according to a first embodiment of the present invention. 3 is a cross-sectional view taken along the line II of FIG.

  First, the structure of the electric double layer capacitor will be described. As shown in FIG. 3, the electric double layer capacitor 1 of this embodiment includes a cell body 10, an upper terminal 17, and a lower terminal 18. The cell body 10 includes an upper metal case 11, a lower metal case 12, an upper electrode 13, a lower electrode 14, a separator 15, and a gasket 16.

  The upper metal case 11 has a disk part 11a and a wall part 11b extending perpendicularly from the periphery of the disk part 11a. Similarly, the lower metal case 12 has a disk part 12a and a wall part 12b extending vertically from the peripheral edge of the disk part 12a. The disk part 12 a of the lower metal case 12 is configured to be slightly larger than the disk part 11 a of the upper metal case 11.

  In the present embodiment, the upper metal case 11 and the lower metal case 12 are arranged so that the outer surface of the wall portion 11b and the inner surface of the wall portion 12b face each other at substantially equal intervals (that is, the wall portion in the space inside the wall portion 12b). 11b). Here, the annular gasket 16 is sandwiched between the outer periphery of the wall portion 11 b of the upper metal case 11 and the inner periphery of the wall portion 12 b of the lower metal case 12. As a result, the space surrounded by the upper metal case 11 and the lower metal case 12 is sealed from the outside. In this space, an inorganic or organic electrolytic solution is sealed. Moreover, since the gasket 16 is formed of an insulating material, a short circuit between the upper metal case 11 and the lower metal case 12 is prevented.

  The upper end of the wall portion 12b of the lower metal case 12 is bent inward. Accordingly, the upper end of the gasket 16 is strongly pressed between the wall portion 11b of the upper metal case 11 and the wall portion 12b of the lower metal case 12, and the lower portion of the upper metal case 11 is caused by the elastic force of the gasket 16. Omission from the metal case 12 is prevented.

  The upper electrode 13 is a member mainly composed of a porous and conductive material such as activated carbon, and is attached to the inner side (the lower surface side in FIG. 3) of the disk portion 11a of the upper metal case 11 with a conductive adhesive. It is attached. The lower electrode 14 is also a member mainly composed of a porous and conductive material such as activated carbon, and is formed on the inner side (upper surface side in FIG. 3) of the disk portion 12a of the lower metal case 12 by a conductive adhesive. It is pasted.

  The separator 15 is a sheet-like member provided between the upper electrode 13 and the lower electrode 14. The separator 15 prevents the short circuit due to the contact between the upper electrode 13 and the lower electrode 14 while allowing the electrolyte ions to pass therethrough. For this reason, when a potential difference is applied between the upper metal case 11 and the lower metal case 12, ions of the electrolytic solution move to the interface between the electrode and the electrolytic solution, and charging is performed by forming an electric double layer. . On the other hand, when the charged electric double layer capacitor is connected to the circuit, ions are dispersed from the interface with the electrode, and a current flows through the circuit (discharge).

  As described above, the electric double layer capacitor 1 of the present embodiment is formed by combining the upper metal case 11 and the lower metal case 12 having the disk portions 11a and 12a. It becomes roughly coin type. The electric double layer capacitor 1 of this embodiment has a configuration suitable for mounting on a substrate in a state where the substrate and the lower metal case 12 face each other. Specifically, the upper terminal 17 and the lower terminal 18 support the electric double layer capacitor 1 when the electric double layer capacitor 1 is placed on the substrate with the lower metal case 12 facing down. Is slightly lifted from the substrate. Both the upper terminal 17 and the lower terminal 18 are sheet metal members formed by bending a stainless steel thin plate.

  Next, the shapes of the upper terminal 17 and the lower terminal 18 will be described. In the following description, when the electric double layer capacitor 1 is placed on a horizontal plane with the outer surface of the disk portion 12a of the lower metal case 12 facing down, the upper direction is “up”, The lower direction is defined as “down”. Further, a direction from the edge of the disk portions 11a and 12a toward the center is defined as “radially inner”, and a direction from the center toward the edge is defined as “radially outer”.

  As shown in FIGS. 1 and 3, the upper terminal 17 has a first portion 17a that contacts the disc portion 11a of the upper metal case 11 and extends radially outward along the disc portion 11a. In this contact portion, the first portion 17a of the upper terminal 17 is joined to the disk portion 11a of the upper metal case 11 by spot welding.

  The first portion 17a of the upper terminal 17 is formed so as to protrude radially outward from the cell body 10 at two locations, and the first portion 17a is bent downward at the slightly outer portions of the two locations. Yes. Hereinafter, the bent and downward portions are referred to as second portions 17b and 17b '. In other words, the first portion 17a is branched in two directions to become second portions 17b and 17b '. As shown in FIG. 3, each of the second portions 17 b and 17 b ′ is bent slightly outward from the lower surface of the lower metal case 12 a and radially outward. Hereinafter, the bent portion is referred to as third portions 17c and 17c '. The third parts 17c and 17c 'spread substantially horizontally.

  Further, as shown in FIGS. 2 and 3, the lower terminal 18 is a substantially rectangular plate, and is bent in a crank shape by a bending portion 18a located at a substantially center. As a result, the lower terminal 18 is divided into a fourth part 18b and a fifth part 18c parallel to each other with the bent part 18a as a boundary. The fourth portion 18 b of the lower terminal 18 is disposed so that the upper surface thereof is in contact with the lower surface of the disk portion 12 a of the lower metal case 12. And in this contact part, the 4th part 18b is joined to the disk part 12a by spot welding.

  In the present embodiment, the fifth portion 18c of the lower terminal 18 and the third portions 17c and 17c 'of the upper terminal 17 are located at substantially the same height. Therefore, when the electric double layer capacitor 1 is placed on a plane with the disk portion 12a of the lower metal case 12 facing downward, the fifth portion 18c of the lower terminal 18 and the third portions 17c, 17c ′ of the upper terminal 17 are disposed. The cell body 10 of the electric double layer capacitor 1 is supported at the three points, and the disk portion 12a of the lower metal case 12 is slightly lifted from the plane. For this reason, by placing the electric double layer capacitor 1 on the substrate and soldering the fifth portion 18c of the upper terminal 18 and the third portions 17c, 17c ′ of the upper terminal 17 to the substrate, the electric double layer capacitor 1 is placed on the substrate. A multilayer capacitor 1 is mounted.

  In the present embodiment, since the electric double layer capacitor 1 is mounted with the disk portion 12a of the lower metal case 12 floating from the substrate as described above, the third portions 17c and 17c ′ of the upper terminal 17 are soldered. Even if there is a slight amount of solder flow, the upper terminal 17 and the lower metal case 12 are not short-circuited through the flowed solder.

  Solder surfaces are formed on the bottom surfaces of the third portions 17 c and 17 c ′ of the upper terminal 17 and the fifth portion 18 c of the lower terminal 18. Therefore, the electric double layer capacitor 1 can be mounted on the substrate only by placing the electric double layer capacitor 1 on the substrate and performing heat treatment.

  As described above, in the present embodiment, the two third portions 17 c and 17 c ′ branch from the upper terminal 17. That is, the electric double layer capacitor 1 is supported by a total of three points: the fifth portion 18c of the lower terminal 18 and the third portions 17c and 17c 'of the upper terminal 17.

  In particular, in the present embodiment, the third portions 17c and 17c 'of the upper terminal 17 are arranged so as to form an angle of about 90 ° with respect to the center of the disc portion 12a. The fifth portion 18c of the lower terminal 18 is disposed so as to form an angle of about 135 ° with each of the third portions 17c and 17c ′ of the upper terminal 17 with respect to the center of the disk portion 12a. In other words, as shown in FIG. 2, when a virtual square S circumscribing the disk portion 12a of the lower metal case 12 is considered, the upper terminal 17 is connected to two adjacent corners C1 and C2 of the virtual square S. It can also be expressed that the third parts 17c and 17c ′ are arranged. The fifth portion 18c of the lower terminal 18 is disposed substantially adjacent to the side E1 connecting the two corners C3 and C4 of the virtual square S where the third portions 17c and 17c 'are not disposed. Therefore, the center of the disk portion 12a of the lower metal case 12 (which substantially coincides with the center of gravity of the electric double layer capacitor 1) connects the third portions 17c and 17c ′ of the upper terminal 17 and the fifth portion 18c of the lower terminal 18. The electric double layer capacitor 1 is stably supported. For this reason, for example, even if the solder of a specific terminal melts first during the heat treatment and the height of the fifth portion 18b of the lower terminal 18 and the third portions 17c, 17c ′ of the upper terminal 17 is uneven, The electric double layer capacitor 1 does not fall down, and the electric double layer capacitor 1 can be reliably mounted on the substrate.

  Here, the outlines of the tip portions of the third portions 17 c and 17 c ′ of the upper terminal 17 have a right triangle shape along the corners C 1 and C 2 of the virtual square S. Accordingly, the upper terminal 17 and the lower terminal 18 are disposed inside the virtual square S. Therefore, when the electric double layer capacitor 1 is mounted on the substrate, the terminals 17 and 18 are provided in the space above and below the cell body 10 or dead space (virtual square) that is inevitably generated when a circular device is mounted on the substrate. The region between the contour of S and the outer periphery of the disk portion of the lower metal case 12). Therefore, according to the electric double layer capacitor 1 of the present embodiment, the electric double layer capacitor 1 can be mounted with a minimum necessary board space.

  As shown in FIGS. 1 and 3, the third portions 17 c and 17 c ′ of the upper terminal 17 of the present embodiment are disposed radially outward with respect to the lower metal case 12, and the upper terminal It is not covered by the first part 17a or the second part 17b. That is, the upper surfaces of the third portions 17 c and 17 c ′ of the upper terminal 17 can be accessed from above the electric double layer capacitor 1. For this reason, after the surface mounting heat treatment is finished, an ultrasonic probe or the like is pressed against the third portions 17c and 17c ′ of the upper terminal 17 from above the electric double layer capacitor 1 to determine whether soldering has been performed. Inspection can be performed easily. Similarly, a part of the fifth portion 18c of the lower terminal 18 is located in a region between the inner periphery of the virtual square S and the outer periphery of the disk portion 12a. It is possible to easily inspect whether or not the soldering has been performed by pressing against 18c.

  Next, the structure of the second portions 17b and 17b 'of the upper terminal 17 will be described. As shown in FIG. 3, the second portion 17 b ′ of the upper terminal 17 of the present embodiment is gently curved with the upper side projecting radially outward and convexly, and the lower side gently curved projecting radially inner and convex. The shape is substantially S-shaped. With this structure, the second portion 17b 'functions as a leaf spring that can be expanded and contracted to some extent in the vertical direction. Accordingly, the substrate on which the electric double layer capacitor 1 is mounted is warped, and the inclination of the portion where the fifth portion 18c of the lower terminal 18 is in contact with the substrate and the inclination of the portion where the third portion 17c ′ of the upper terminal 17 is in contact with the substrate. Are different, the second portion 17b of the upper terminal 17 bends, and as a result, both the fifth portion 18c of the lower terminal 18 and the third portion 17c ′ of the upper terminal 17 can be brought into close contact with the substrate. In FIG. 3, only one second part 17b 'and third part 17c' are shown, but the same applies to the other second part 17b and third part 17c.

  The shapes of the second portions 17b and 17b 'of the upper terminal 17 do not necessarily have to be substantially S-shaped. For example, as shown in FIG. 4A, the second portions 17b and 17b 'may be planar. Alternatively, as shown in FIG. 4B, the second parts 17b and 17b 'may be bent in a plurality of places (three places in the drawing). Furthermore, curl so as to protrude outward in the radial direction of the cell body 10 at the substantially vertical center of the second parts 17b and 17b ′ as shown in FIG. 4C, or as shown in FIG. 4D. It is good also as a structure curled so that it may protrude inside the radial direction of the main body 10. FIG. Alternatively, instead of curling the second parts 17b 'and 17b, it may be configured to be bent as shown in FIGS. The upper terminal 17 of FIGS. 4B to 4F is similar to that of the present embodiment even if the substrate on which the electric double layer capacitor 1 is mounted is warped or the like, Both the third portions 17c and 17c ′ of the upper terminal 17 can be brought into close contact with the substrate.

  In the embodiment of the present invention described above, the first portion a of the upper terminal 17 is branched and two sets of the second portion 17b and the third portion 17c are provided. However, the present invention is not limited to this configuration. As shown in FIG. 5, the second portion 17b and the third portion 17c are provided one by one, and the second portion 17b is shown in FIGS. The structure bent as in () to (f) is also within the scope of the present invention.

  Moreover, in this embodiment, it is comprised so that the upper terminal 17 and the lower terminal 18 may enter in the virtual square S which the disk part 12a of the lower metal case 12 inscribes. However, the present invention is not limited to the above configuration. That is, a configuration in which the terminals 17 and 18 are not completely accommodated in the virtual square S and slightly protrudes is also within the scope of the present invention. Specifically, the virtual square S may be a square that is slightly larger than the disk portion 12a of the lower metal case 12, and circumscribes a circle that is enlarged about 10% in the horizontal direction from the center of the disk portion 12a.

  Further, as shown in FIG. 1, in the present embodiment, the first portion 17 a of the upper terminal 17 branches in two directions near the edge of the disk portion 11 a of the upper metal case 11. Yes. In other words, the first portion 17a of the upper terminal 17 has a substantially fan shape. However, the present invention is not limited to the above configuration. For example, as shown in FIG. 6, a configuration in which the branch of the first portion 17a occurs at a position closer to the center of the disk portion 11a, and the first portion 17a has a substantially V shape as a whole is also within the scope of the present invention. is there. In such a configuration, the shape when the upper terminal 17 is unfolded is also V-shaped. In general, when the upper terminal 17 is manufactured, a large number of unfolded upper terminals 17 are obtained from a single steel sheet by punching with a pressing device. Therefore, if the upper terminal 17 before bending is V-shaped as in this example, the amount of steel plate used per upper terminal 17 is reduced, and the upper terminal before bending is almost free of any gap in the steel sheet as shown in FIG. Since 17 can be arranged, more upper terminals 17 can be obtained from one steel plate.

  In the first embodiment of the present invention described above, a virtual square S circumscribing the disc portion 12a of the lower metal case 12 (or a square circumscribing a circle slightly enlarging the disc portion 12a of the lower metal case 12). A pair of third portions 17c of the upper terminal 17 is disposed at each of two adjacent corners. However, the present invention is not limited to this configuration. For example, other configurations such as the second embodiment of the present invention described below are also within the scope of the present invention. In the second embodiment, the same or similar reference numerals are given to the same or similar parts as in the first embodiment.

  8 and 9 are a top view and a bottom view, respectively, of an electric double layer capacitor that is an electrochemical cell of the present embodiment. 10 and 11 are a II-II sectional view and a III-III sectional view of FIG. 8, respectively.

  First, the structure of the electric double layer capacitor will be described. As shown in FIG. 10, the electric double layer capacitor 1 of this embodiment includes a cell body 10, an upper terminal 17, and a lower terminal 18. The cell body 10 includes an upper metal case 11, a lower metal case 12, an upper electrode 13, a lower electrode 14, a separator 15, and a gasket 16.

  The upper metal case 11 has a disk part 11a and a wall part 11b extending perpendicularly from the periphery of the disk part 11a. Similarly, the lower metal case 12 has a disk part 12a and a wall part 12b extending perpendicularly from the periphery of the disk part 12a. The disk part 12 a of the lower metal case 12 is configured to be slightly larger than the disk part 11 a of the upper metal case 11.

In the present embodiment, the upper metal case 11 and the lower metal case 12 are arranged so that the outer surface of the wall portion 11b and the inner surface of the wall portion 12b face each other at substantially equal intervals (that is, the wall portion in the space inside the wall portion 12b). 11b). Here, the annular gasket 16 is sandwiched between the outer periphery of the wall portion 11 b of the upper metal case 11 and the inner periphery of the wall portion 12 b of the lower metal case 12. As a result, the space surrounded by the upper metal case 11 and the lower metal case 12 is sealed from the outside. In this space, an inorganic or organic electrolytic solution is sealed. Moreover, since the gasket 16 is formed of an insulating material, a short circuit between the upper metal case 11 and the lower metal case 12 is prevented.

  The upper end of the wall portion 12b of the lower metal case 12 is bent inward. Accordingly, the upper end of the gasket 16 is strongly pressed between the wall portion 11b of the upper metal case 11 and the wall portion 12b of the lower metal case 12, and the lower portion of the upper metal case 11 is caused by the elastic force of the gasket 16. Omission from the metal case 12 is prevented.

  The upper electrode 13 is a member mainly composed of a porous and conductive material such as activated carbon, and is attached to the inner side (the lower surface side in FIG. 10) of the disk portion 11a of the upper metal case 11 with a conductive adhesive. It is attached. The lower electrode 14 is also a member mainly composed of a porous and conductive material such as activated carbon, and is formed on the inner side (upper surface side in FIG. 10) of the disk portion 12a of the lower metal case 12 by a conductive adhesive. It is pasted.

  The separator 15 is a sheet-like member provided between the upper electrode 13 and the lower electrode 14. The separator 15 prevents the short circuit due to the contact between the upper electrode 13 and the lower electrode 12, while allowing the electrolyte ions to pass therethrough. For this reason, when a potential difference is applied between the upper metal case 11 and the lower metal case 12, ions of the electrolytic solution move to the interface between the electrode and the electrolytic solution, and charging is performed by forming an electric double layer. . On the other hand, when a charged electric double layer capacitor is connected to a circuit, ions are dispersed from the electrode, and a current flows through the circuit (discharge).

  As described above, the electric double layer capacitor 1 of the present embodiment is formed by combining the upper metal case 11 and the lower metal case 12 having the disk portions 11a and 12a. It becomes roughly coin type. The electric double layer capacitor 1 of this embodiment has a configuration suitable for mounting on a substrate in a state where the substrate and the lower metal case 12 face each other. Specifically, the upper terminal 17 and the lower terminal 18 support the electric double layer capacitor 1 when the electric double layer capacitor 1 is placed on the substrate with the lower metal case 12 facing down. Is slightly lifted from the substrate. Both the upper terminal 17 and the lower terminal 18 are sheet metal members formed by bending a stainless steel thin plate.

  Next, the shapes of the upper terminal 17 and the lower terminal 18 will be described. In the following description, when the electric double layer capacitor 1 is placed on a horizontal plane with the outer surface of the disk portion 12a of the lower metal case 12 facing down, the upper direction is “up”, The lower direction is defined as “down”. Further, a direction from the edge of the disk portions 11a and 12a toward the center is defined as “radially inner”, and a direction from the center toward the edge is defined as “radially outer”.

  As shown in FIG. 9, the lower terminal 18 is an elongated plate, and a fourth portion 18 b that extends in a circular shape is formed radially outward at the center. Further, fifth portions 18 c and 18 c ′ are formed at both ends of the lower terminal 18. As shown in FIG. 11, the lower terminal 18 is bent in a crank shape between the fourth portion 18b and the fifth portions 18c, 18c ′ (folded portions 18a, 18a ′), and the fourth portion 18b. Is positioned one step higher than the fifth portions 18c and 18c ′. The fourth portion 18b and the fifth portions 18c and 18c 'are substantially parallel to each other. The fourth portion 18 b of the lower terminal 18 is disposed so that the upper surface thereof is in contact with the lower surface of the disk portion 12 a of the lower metal case 12. And in this contact part, the 4th part 18b is joined to the disk part 12a by spot welding.

  Further, as shown in FIG. 8, the upper terminal 17 is an elongated plate, and a circular first portion 17a is formed at the center thereof. The first part 17a is in contact with the disk part 11a of the upper metal case 11, and the first part 17a of the upper terminal 17 is joined to the disk part 11a of the upper metal case 11 by spot welding.

  The upper terminal 17 extends from the circular first portion 17a in two directions opposite to each other, and is formed so as to protrude outward in the radial direction from the cell body 10, and at each of the two protruding points, the upper terminal 17 Bends downward. Hereinafter, the bent and downward portions are referred to as second portions 17b and 17b '. In other words, the first part 17a branches into two opposite directions and becomes second parts 17b and 17b '. Further, as shown in FIG. 10, each of the second portions 17b and 17b 'is bent outward in the radial direction slightly below the lower surface of the lower metal case 12a. Hereinafter, the bent tip portion is referred to as a third portion 17c, 17c '. The third parts 17c and 17c 'spread substantially horizontally.

  In the present embodiment, the fifth portions 18c and 18c 'of the lower terminal 18 and the third portions 17c and 17c' of the upper terminal 17 are located at substantially the same height. Accordingly, when the electric double layer capacitor 1 is placed on a horizontal plane with the disk portion 12a of the lower metal case 12 facing down, the fifth portions 18c and 18c ′ of the lower terminal 18 and the third portion 17c of the upper terminal 17 are disposed. , 17c ′, the cell body 10 of the electric double layer capacitor 1 is supported, and the disk portion 12a of the lower metal case 12 is slightly lifted from the horizontal plane. For this reason, the electric double layer capacitor 1 is placed on the substrate, and the fifth portions 18c and 18c ′ of the lower terminal 18 and the third portions 17c and 17c ′ of the upper terminal 17 are soldered to the substrate. An electric double layer capacitor 1 is mounted.

  In the present embodiment, since the electric double layer capacitor 1 is mounted with the disk portion 12a of the lower metal case 12 floating from the substrate as described above, the third portions 17c and 17c ′ of the upper terminal 17 are soldered. Even if there is a slight amount of solder flow, the upper terminal 17 and the lower metal case 12 are not short-circuited through the flowed solder.

  Solder surfaces are formed on the bottom surfaces of the third portions 17c and 17c 'of the upper terminal 17 and the fifth portions 18c and 18c' of the lower terminal 18. Therefore, the electric double layer capacitor 1 can be mounted on the substrate simply by placing the electric double layer capacitor 1 on the substrate and performing heat treatment.

  As described above, in the present embodiment, the upper terminal 17 is divided into two third portions 17c and 17c '. That is, the electric double layer capacitor 1 is supported by a total of four points, that is, the fifth parts 18c and 18c 'of the lower terminal 18 and the third parts 17c and 17c' of the upper terminal 17.

  In particular, in the present embodiment, the third portions 17c and 17c ′ of the upper terminal 17 and the fifth portions 18c and 18c ′ of the lower terminal 18 respectively have an angle of about 90 ° with respect to the center of the disk portion 12a. It is arranged to make. That is, as shown in FIG. 8 or 9, the third portions 17c and 17c of the upper terminal 17 are formed at two corners C3 and C2 of the virtual square S circumscribing the disk portion 12a of the lower metal case 12 to each other. 'Is arranged respectively. Further, the fifth portions 18c and 18c 'of the lower terminal 18 are respectively disposed at two diagonal corners C4 and C1 of the virtual square S where the third portions 17c and 17c' are not disposed. For this reason, the center (that is, the center of gravity) of the disk portion 12a of the lower metal case 12 is located within a virtual square connecting the third portions 17c and 17c ′ of the upper terminal 17 and the fifth portions 18c and 18c ′ of the lower terminal 18. Thus, the electric double layer capacitor 1 is stably supported. For this reason, for example, the solder of a specific terminal melts first during the heat treatment, and the heights of the fifth portions 18c and 18c ′ of the lower terminal 18 and the third portions 17c and 17c ′ of the upper terminal 17 are biased. However, the electric double layer capacitor 1 does not fall down, and the electric double layer capacitor 1 can be reliably mounted.

  Here, the outlines of the tip portions of the third portions 17c and 17c ′ of the upper terminal 17 have a right triangle shape along the corners C3 and C2 of the virtual square S. That is, the upper terminal 17 and the lower terminal 18 are arranged inside the virtual square S. In addition, right-angle portions along the corners C4 and C1 of the virtual square S are formed at the tips of the fifth portions 18c and 18c 'of the lower terminal 18. For this reason, when the electric double layer capacitor 1 is mounted on the substrate, the terminals 17 and 18 are provided in the space above and below the cell body 10 or dead space (virtual space that is inevitably generated when mounting a circular device on the substrate. It is arranged in a region between the outline of the square S and the outer periphery of the disk part of the lower metal case 12. Therefore, according to the electric double layer capacitor 1 of the present embodiment, the electric double layer capacitor 1 can be mounted with a minimum necessary board space.

  Further, as shown in FIGS. 8 and 10, the third portions 17c and 17c ′ of the upper terminal 17 of the present embodiment are arranged radially outward with respect to the lower metal case 12, and It is not covered by the first part 17a or the second part 17b. Similarly, as shown in FIGS. 9 and 11, the tip ends of the fifth portions 18 c and 18 c ′ of the lower terminal 18 are disposed radially outward with respect to the lower metal case 12 and are connected to the upper terminal 17. Not covered. That is, the upper surfaces of the third portions 17 c and 17 c ′ of the upper terminal 17 and the upper surfaces of the fifth portions 18 c and 18 c ′ of the lower terminal 18 can be accessed from above the electric double layer capacitor 1. For this reason, after the surface mounting heat treatment is completed, an ultrasonic probe or the like is applied to the third portions 17c and 17c ′ of the upper terminal 17 and the fifth portions 18c and 18c ′ of the lower terminal 18 from above the electric double layer capacitor 1. It is possible to easily inspect whether the soldering has been performed by pressing.

  Next, the structure of the second portion 17b of the upper terminal 17 will be described. As shown in FIG. 10, the second portions 17b and 17b ′ of the upper terminal 17 of the present embodiment are gently curved with the upper side projecting radially outward and the lower side gently projecting radially inward. It is a substantially S-shaped shape that curves in a straight line. With this structure, the second portions 17b and 17b 'function as leaf springs that can be expanded and contracted to some extent in the vertical direction. Accordingly, the substrate on which the electric double layer capacitor 1 is mounted is warped, and the inclination of the portion where the fifth portions 18c and 18c ′ of the lower terminal 18 are in contact with the portion where the third portions 17c and 17c ′ of the upper terminal 17 are in contact. When the inclination is different, the second parts 17b and 17b ′ of the upper terminal 17 are bent, and as a result, both the fifth parts 18c and 18c ′ of the lower terminal 18 and the third parts 17c and 17c ′ of the upper terminal 17 are It can be adhered to the substrate.

  Note that the shapes of the second portions 17b and 17b 'of the upper terminal 17 are not necessarily substantially S-shaped. That is, as shown in FIG. 12A, the second portions 17b and 17b 'may be planar. Alternatively, as shown in FIG. 12B, the second portions 17b and 17b 'may be bent in a plurality of places (three places in the drawing). Further, curl so as to protrude outward in the radial direction of the cell body 10 at the substantially vertical center of the second parts 17b and 17b ′ as shown in FIG. 12C, or as shown in FIG. It is good also as a structure curled so that it may protrude inside the radial direction of the main body 10. FIG. Alternatively, instead of curling the second portions 17b and 17b ', a configuration in which the second portions 17b and 17b' are bent as shown in FIGS. The upper terminal 17 of FIGS. 12B to 12F is similar to that of the present embodiment even if the substrate on which the electric double layer capacitor 1 is mounted is warped or the like, Both the third portions 17c of the upper terminal 17 can be brought into close contact with the substrate.

  In the first and second embodiments of the present invention described above, the third portions 17c and 17c ′ of the upper terminals 17 and 17 ′ are arranged in the radial direction of the cell body 10 from the lower ends of the second portions 17b and 17b ′. It extends outward. However, the present invention is not limited to this configuration. For example, in the first embodiment, as shown in FIGS. 13A to 13G, the third portion 17c ′ is replaced with the second portion 17b ′. It is good also as a structure extended in the radial direction inner side of the cell main body 10 from the lower end of this. Alternatively, in the second embodiment, as shown in FIGS. 14A to 14G, the third portions 17c and 17c ′ are located radially inward of the cell body 10 from the lower ends of the second portions 17b and 17b ′. It is good also as the structure extended.

1 is a top view of an electric double layer capacitor according to a first embodiment of the present invention. 1 is a bottom view of an electric double layer capacitor according to a first embodiment of the present invention. It is II sectional drawing of FIG. It is a side view which shows the modification of the upper terminal of the 1st Embodiment of this invention. It is a top view of another example of the electric double layer capacitor of the first embodiment of the present invention. It is a top view of other examples of an electric double layer capacitor of a 1st embodiment of the present invention. FIG. 7 shows a state when the upper terminal of the electric double layer capacitor shown in FIG. 6 is taken from a steel plate. It is a top view of the electric double layer capacitor by the 2nd Embodiment of this invention. It is a bottom view of the electric double layer capacitor by the 2nd Embodiment of this invention. It is II-II sectional drawing of FIG. It is III-III sectional drawing of FIG. It is a side view which shows the modification of the upper terminal of the 2nd Embodiment of this invention. It is a side view which shows the modification of the upper terminal of the 1st Embodiment of this invention. It is a side view which shows the modification of the upper terminal of the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor 10 Cell main body 11 Upper metal case 11a Disk part 11b Wall part 12 Lower metal case 12a Disk part 12b Wall part 17 Upper terminal 17a 1st part 17b 2nd part 17c 3rd part 18 Lower terminal 18a Bending part 18b Part 4 18c Part 5

Claims (17)

A cell body having a substantially disk-shaped outer shape, and electrodes having different polarities on the upper surface and the lower surface;
An upper terminal joined to the electrode on the upper surface side of the cell body;
A lower terminal joined to the electrode on the lower surface side of the cell body,
The upper terminal is joined to the electrode on the upper surface side, a first portion extending toward an edge of the upper surface of the cell body, and a plurality of second portions extending downward from the first portion. A plurality of third portions bent from respective lower ends of the plurality of second portions and extending in a radial direction of the cell body,
Projection of the upper and lower terminals onto a plane including the lower surface of the cell body is approximately contained in a square circumscribing the projection of the cell body onto the plane,
The projection of the plurality of second portions onto the plane is disposed in the vicinity of two or more corners of the square.   2. The electrochemical cell according to claim 1, wherein at least two of the projections of the plurality of second portions onto the plane are respectively disposed at two adjacent corners of the square. There are two corners where the projection of the second part onto the plane is not located,
3. The projection of the lower terminal on the plane is disposed substantially adjacent to the side of the square having two corners at which the projection of the second portion is not disposed on the plane. The electrochemical cell according to 1.   4. The electrochemical cell according to claim 2, wherein the shape of the first portion of the upper terminal is V-shaped with both ends connected to the second portion. 5. Projections of the plurality of second portions onto the plane are disposed at two corners of the diagonal of the square;
2. The electrochemical cell according to claim 1, wherein projections of the second portion onto the plane are not arranged at the other two corners of the square. The lower terminal has an elongated shape;
The lower terminal and the lower surface of the cell body are joined at a substantially central portion in the major axis direction of the lower terminal,
The electrochemical cell according to claim 5, wherein both ends of the lower terminal in the major axis direction are arranged at two corners of the square where the projection of the second portion on the plane is not arranged. Right-angle portions are formed at both ends in the long axis direction of the lower terminal,
The electrochemical cell according to claim 6, wherein the projection of the right-angled portion onto the plane is configured along a corner of the corresponding square.   The electrochemical cell according to claim 6 or 7, wherein a substantially central portion in the major axis direction of the lower terminal is formed wider than other portions of the lower terminal.   The electrochemical cell according to any one of claims 1 to 8, wherein the third portion extends radially outward of the cell body from a lower end of the second portion. The third portion of the upper terminal has a substantially right triangle shape,
10. The electrochemical cell according to claim 9, wherein the upper terminal is arranged so that a projection of a right-angle portion of the third portion onto the plane follows a corner of the square.   At least a portion of the second portion of the upper terminal is bent so as to protrude radially outward or inward of the cell body so that the second portion can bend in the vertical direction. The electrochemical cell according to claim 1, comprising at least one part. A cell body having a substantially disk-shaped outer shape, and electrodes having different polarities on the upper surface and the lower surface;
An upper terminal joined to the electrode on the upper surface side of the cell body;
A lower terminal joined to the electrode on the lower surface side of the cell body;
With
The upper terminal is joined to the electrode on the upper surface side and extends toward the edge of the upper surface of the cell body, and a second portion extends downward from the first portion; A third portion extending from the lower end of the second portion toward the radially outer side of the cell body,
The second portion of the upper terminal has at least one bent portion that is bent so as to protrude radially outward or inward of the cell body so that the second portion can bend in the vertical direction. Have
An electrochemical cell characterized by that.   The second portion of the upper terminal is provided with a plurality of bent portions arranged in the vertical direction, and the protruding directions of any two bent portions continuous in the vertical direction are different from each other. The electrochemical cell according to claim 12.   The second portion of the upper terminal is formed in an S shape in which one of the upper side and the lower side protrudes radially outward of the cell body and the other protrudes radially inward of the cell body. The electrochemical cell according to claim 13.   The electrochemical cell according to any one of claims 12 to 14, wherein the bent portion is formed by bending the upper terminal.   The electrochemical cell according to any one of claims 12 to 14, wherein the bent portion is formed by curling the upper terminal.   The electrochemical cell according to claim 1, wherein the electrochemical cell is an electric double layer capacitor.

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