JP2009117582A - Capacitor unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor unit which enables higher working efficiency of laser welding connection at the manufacturing step of the capacitor unit as well as higher reliability of welding without losing ease of connection between capacitors of conventional capacitor units and space-saving features of the entire capacitor unit. <P>SOLUTION: A structure, in which welding assisting plates 8 and 9 are welded in advance to points at which a connection member 7 is to be welded to each connection member welding portion 3c of a metal case 2 and a terminal plate 3, can surely suppress the possibility of electrolyte leakage or the like resulting from the occurrence of a communication hole in an exterior member caused by excessive melting of a metal at the time of welding of the connection member, thereby allowing a manufacturing yield to be enhanced and easily increasing a welding area to increase the withstand current and the connection area between the connection member 7 and a capacitor to be connected. As a result, a capacitor unit can have higher connection reliability and lower resistance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a capacitor unit that is used for power assist and power storage in electronic devices and hybrid vehicles.

  7A to 7C are a plan view, a front sectional view, and a bottom view showing the structure of an electric double layer capacitor used in a conventional capacitor unit.

  In FIG. 7, reference numeral 13 denotes a capacitor element. The capacitor element 13 is formed on a current collector made of aluminum foil by forming a carbon-based electrode layer composed of activated carbon, a conductive auxiliary agent that enhances conductivity, and a binder that binds the activated carbon together. Is used as an electrode. This electrode has a structure in which the positive electrode and the negative electrode are paired with each other, and the positive electrode and the negative electrode are shifted in the opposite directions with a separator interposed therebetween, and both are wound so that a part is exposed.

  Reference numeral 14 denotes a bottomed cylindrical metal case made of aluminum and containing a capacitor element 13 and a driving electrolyte (not shown). Reference numeral 14a denotes a recess provided on the bottom surface of the metal case 14. A part of the bottom surface of the metal case 14 protrudes inward, and the recess 14a and one end surface of the capacitor element 13 are brought into contact with each other at a connection location. Laser welding (welding mark 14b) is performed. Therefore, sufficient connection with the capacitor element 13 is achieved. Thus, the capacitor element 13 and the inner bottom surface of the metal case 14 are electrically connected, and the entire metal case 14 has one polarity.

  Reference numeral 15 denotes a terminal board. As will be described later, the end surface of the opening of the metal case 14 is subjected to curling (curling processing portion 14c), and an end surface is provided on the terminal plate 15 at a position higher than the apex of the curling processing portion 14c in order to prevent a short circuit. A welded portion 15a is provided. Similarly to the bottom surface of the metal case 14, the terminal plate 15 has a recess 15b, and is electrically connected to the recess 15b and the other end surface of the capacitor element 13 by laser welding (welding mark 15c). On the terminal board 15, there is another electrolytic solution injection hole 15d, and after the electrolytic solution is injected, the electrolytic solution injection hole 15d is closed by a rubber plug 17.

  Reference numeral 16 denotes an annular insulating member. The insulating member 16 is disposed on the inner peripheral surface of a drawn portion 14 d that has been drawn near the opening of the metal case 14, and the terminal plate 15 is provided on the insulating member 16. .

  Reference numeral 18 denotes a sealing rubber. The sealing rubber 18 is disposed on the peripheral edge of the upper surface of the terminal plate 15, and the sealing rubber 18 positioned on the inner periphery of the curling portion 14 c is compressed and sealed by subjecting the opening of the metal case 14 to curling. Is something to do.

  In addition, h has shown the difference of the height of the vertex of the welding part 15a and the vertex of the curling process part 14c.

  FIGS. 8A to 8C are a plan view, a front partial sectional view, and a bottom view showing a state in which two conventional capacitors are connected.

  In FIG. 8, 19 indicates one capacitor, 20 indicates the other capacitor, and the same constituent elements as those of the capacitor shown in FIG.

  Reference numeral 21 denotes a connection member, and the connection member 21 is partially tapered so that the connection member 21 is formed in a step shape. As a result, the high side of the connection member 21 is welded to one capacitor 19 as shown in FIG. The lower side is welded to the curling portion 14c of the other capacitor 20 by laser welding.

  With the above connection method, the capacitor unit can connect a plurality of capacitors in series.

  Capacitor units employing such a connection method can be connected using only the terminal plate 15 of each capacitor and the space in the vicinity thereof when connecting in series, thereby eliminating unnecessary parts. In addition, by reducing the volume per capacitor, it is possible to save space and reduce the cost of the entire capacitor unit.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 2007-189188 A

  However, in the conventional capacitor unit, as shown in the plan view of FIG. 8, when one capacitor 19 and the other capacitor 20 are connected in series, the curling portion 14c of either capacitor has a taper. Although the connecting member 21 is welded by laser welding, the curling portion 14c has a small area that can be used for welding, and laser welding is difficult. Furthermore, when used as an on-vehicle power supply assist, load resistance due to charging / discharging with a large current is particularly required for the capacitor unit. There has been a problem that the degree of freedom of design with respect to the welded area may be reduced.

  Further, as a solution to this problem, there is a method of welding the connecting member 21 to the side surface of the metal case 14 instead of the curling portion 14c. In this case, the thickness of the aluminum on the side surface of the metal case 14 is very thin. When lap welding is performed by laser irradiation from the connecting member 21 side in a state where 21 is overlapped on the metal case 14, the melted portion of the metal due to laser irradiation penetrates into the capacitor, and the electrolyte leaks from the metal case 14. There was a problem that there is a risk of end.

  The present invention solves the problems of these conventional capacitor units, and does not impair the convenience of connection between the capacitors of the conventional capacitor unit or the space saving of the entire capacitor unit. An object of the present invention is to provide a capacitor unit that enhances work efficiency and at the same time increases the reliability of welding.

  In order to solve the above-described problems, the present invention includes a bottomed cylindrical metal case that houses a capacitor element, and a terminal plate that seals the opening of the metal case. The terminal plate and the metal case have different polarities. In a state where a plurality of capacitors are arranged in parallel with each other, a terminal plate of one adjacent capacitor and a metal case of the other capacitor are laser-welded through a connecting member, thereby providing an electric In the connected capacitor unit, a welding auxiliary plate is lap welded to the outer surface of the metal case, and the welding auxiliary plate and the connecting member are lap welded.

  In the capacitor unit according to the present invention, when a capacitor unit is configured by connecting capacitors, one capacitor is welded with a welding auxiliary plate on the outer surface of the metal case, and the connection member is overlap-welded on the welding auxiliary plate. With this configuration, the laser-weldable area is expanded, the working efficiency of laser welding the connecting member is remarkably improved, and at the same time, the current resistance can be improved by increasing the weld area. Further, in the conventional configuration, the assembly of the capacitor alone is completed and the connection must be performed in a state where the electrolyte exists in the capacitor. According to the configuration of the present invention, the welding auxiliary plate is connected in advance. After inserting the element into the metal case and sealing the opening of the metal case with the terminal plate and sealing rubber, the electrolyte is injected from the electrolyte injection hole provided in the terminal plate, and the electrolyte injection hole is closed. When the auxiliary welding plate is connected to the outer surface of the metal case, there is no electrolyte inside the metal case. The internal pressure of the capacitor rises and the melted part of laser welding does not scatter to the outside, and it is possible to securely pass through the welding auxiliary plate in a state where defects such as through holes cannot occur on the side of the capacitor. It is possible to weld the connecting member, and the reliability can be greatly improved. Further, the location where the welding auxiliary plate is provided can increase the welding area and the welding strength with respect to laser welding from the viewpoint of the thickness of the wall. In addition, welding conditions for laser welding can be expanded. In addition, this configuration enables connection by resistance welding, arc welding (tungsten inert gas welding, metal inert gas arc welding, metal active gas welding, plasma welding, etc.), ultrasonic welding, etc., and the degree of freedom of the connection configuration is greatly expanded. In addition, leakage can be suppressed in terms of reliability, and a dramatic effect can be obtained in which the connection area can be expanded.

(Embodiment 1)
Hereinafter, the invention described in the first, third, fourth, and fifth aspects of the present invention will be described using the first embodiment.

  1A to 1C are a plan view, a front sectional view, and a bottom view showing a configuration of a capacitor used in the capacitor unit according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a capacitor element. The capacitor element 1 is formed by forming a carbon-based electrode layer composed of activated carbon, a conductive agent, and a binder on a current collector made of aluminum foil or copper foil. Is used as an electrode. And this electrode makes a pair with a positive electrode and a negative electrode, together with a separator interposed between them, a carbon-based electrode layer non-formed portion is provided at one end of each collector of the positive and negative electrodes. The positive and negative electrodes are shifted and stacked in opposite directions so that the portions are exposed. Each electrode is taken out from the end face of the exposed portion of the carbon-based electrode layer where the positive and negative electrode current collectors after winding are exposed.

  Reference numeral 2 denotes a bottomed cylindrical metal case made of aluminum, stainless steel, or steel. The metal case 2 is configured to accommodate a capacitor element 1 impregnated with a driving electrolyte not shown. . In addition, a recess 2a is provided on the bottom surface of the metal case 2, and the end surface of the unexposed portion of the carbon-based electrode layer of the capacitor element 1 is exposed to the recess 2a protruding to the inside of the metal case 2. The contact point is mechanically and electrically connected by laser welding (welding mark 2b).

  3 is a terminal plate made of aluminum, stainless steel, or steel as a base material. The terminal plate 3 is also provided with a concave portion 3a protruding inside the metal case 2 in order to take out an electrode from the capacitor element 1, and the other end of the capacitor element 1 is provided. The exposed end surface of the unexposed portion of the carbon-based electrode layer and the bottom surface of the recess 3a are mechanically and electrically connected by laser welding (welding trace 3b). The terminal plate 3 is further provided with a welded portion 3c, and the height of the upper surface portion of the welded portion 3c is set to be higher than the height of the opening (curling portion 2c) of the metal case 2 subjected to curling. Yes. This is because, when a connecting member to be described later is welded to the welded portion 3c, if this condition is not met, it will come into contact with a part of the metal case 2 having a different polarity of electricity, causing a short circuit.

  Reference numeral 4 denotes a rubber plug, and the rubber plug 4 serves to block an electrolyte solution injection hole (not shown) provided on the terminal plate 3 after the driving electrolyte solution is injected. Further, the rubber plug 4 is made of butyl rubber or ethylene propylene terpolymer, and the rubber plug 4 has a hook-like shape with a tapered tip, so that the hook portion is engaged with the back surface of the terminal plate 3 after being inserted into the electrolyte injection hole. It is configured to prevent it from falling off and falling off.

  Reference numeral 5 denotes an annular insulating member made of an insulating material. The insulating member 5 closely contacts and covers the side surface of the terminal plate 3 with the inner peripheral side surface, and at the same time, the outer peripheral side surface of the insulating member 5 and the inner peripheral side surface of the metal case 2 are in close contact with each other. It is fixed with. This prevents a part of the terminal plate 3 from coming into contact with the inner surface of the metal case 2 to cause a short circuit.

  6 is a sealing rubber. The sealing rubber 6 is disposed on the peripheral edge of the upper surface of the terminal plate 3, and the sealing rubber 6 located on the inner periphery of the curling portion 2 c is compressed and sealed by subjecting the opening of the metal case 2 to curling. Is something to do.

  Further, there is a risk of contact in order to prevent a short circuit due to contact between the portion of the electrode that is electrically connected to the terminal plate 3 of the capacitor element 1 and the inner surface of the metal case 2 in the vicinity thereof. It has a structure in which an insulating tape is attached to the inner surface of the metal case 2. However, it is not shown in the present embodiment. This insulating tape can also be prevented from short-circuiting by applying an insulating coating to the inner surface of the metal case 2 at that portion.

  2A and 2B show a plan view and a front view of the connection member 7 used for connecting a plurality of capacitors according to the present embodiment. In FIG. 2, reference numeral 7a denotes a welded portion 3c provided on the terminal plate 3 and a flat surface portion to be welded by laser welding. 6 has a shape that does not protrude partly. The connecting member 7 is bent vertically to the bottom surface side of the metal case 2 at a point past the outer diameter of the metal case 2 (vertical portion 7b). The vertical portion 7b is continuous with the side surface portion 7c, and the side surface portion 7c is made of metal. The side surface of the case 2 is partially drawn along the side surface. The connecting member 7 is preferably made of aluminum or copper as a base material from the viewpoint of the resistance value of the connecting member 7, but is not limited thereto.

  In FIG. 3, before assembling the capacitors to be connected to a plurality of capacitors, the welding auxiliary plate 8 is formed in a shape along the side surface of the metal case 2 in advance to the location where the connecting member 7 is laser welded on the side surface of the metal case 2. The front view of the laser-welded (weld mark 8a) capacitor is shown. As a result, the wall thickness is increased only at a location necessary for welding, and more reliable welding can be performed when the connection member 7 is welded. The welding auxiliary plate 8 is preferably made of the same material as the metal case 2 from the viewpoint of the melting point during laser welding, but is not limited thereto.

  FIG. 4 is a plan view of a capacitor in which a welding auxiliary plate 9 is previously welded to the upper surface of the welded portion 3c of the terminal plate 3 by laser welding (welding mark 9a) before assembling the capacitors to be connected to a plurality of capacitors. Yes. As a result, similarly to the above, laser welding can be performed more reliably. The welding auxiliary plate 9 is also preferably made of the same material as the terminal plate 3 from the viewpoint of the melting point during laser welding, but is not limited thereto.

  FIGS. 5A to 5C are a plan view and a front view showing a state in which a capacitor in which the welding auxiliary plates 8 and 9 indicated by broken lines are previously welded to a place where the connecting member 7 is laser welded is connected. , Shows a bottom view. When welding each of the auxiliary welding plates 8 and 9 to the flat surface portion 7a and the side surface portion 7c of the connecting member 7, the welding location in this embodiment (metal case side surface welding trace 8b, terminal plate outer surface side welding trace 9b ) Is preferably different from the positions of the welding marks 8a and 9a. This is because the surface portion once laser-welded is deformed and it is difficult to control the welding state. The weld marks 8a and 9a, the metal case side surface weld marks 8b, and the terminal plate outer surface side weld marks 9b shown in FIGS. 3 to 5 are examples, and the weld marks 8a and 9a If the welding positions of the metal case side surface welding mark 8b and the terminal plate outer surface side welding mark 9b are different, the welding shape is not limited.

  As described above, in the capacitor unit according to the present invention, before assembling the capacitor, the welding auxiliary plates 8 and 9 are laser-welded to the side surface of the metal case 2 and the welded portion 3c in advance, and the welding auxiliary plates 8 are assembled. , 9 by laser welding the connecting member 7 so that a plurality of capacitors constitute a unit. This expands the range of laser welding conditions imposed at the time of joining the connecting member 7 due to the risk of electrolyte leakage due to excessive welding without impairing the conventional space and cost savings, and by expanding the welding area The effect of improving the current resistance of the welded portion and finally improving the yield during manufacturing can be obtained.

  In the embodiment, the case of laser welding is described as the welding method. However, the structure of the capacitor alone using the welding auxiliary plates 8 and 9 of the present invention is the capacitor connected to the metal case 2 to which the welding auxiliary plate 8 is connected in advance. After the element 1 is inserted and the opening of the metal case 2 is sealed with the terminal plate 3 and the sealing rubber 6, the electrolytic solution is injected from the electrolytic solution injection hole provided in the terminal plate 3, and the electrolytic solution injection hole Because it is a structure that can be an assembly process that closes the surface, it can be joined by resistance welding, arc welding (tungsten inert gas welding, metal inert gas arc welding, metal active gas welding, plasma welding, etc.), ultrasonic welding, etc. The degree of freedom of the connection configuration is particularly wide, and leakage can be suppressed from the viewpoint of reliability, and a dramatic effect can be obtained in which the connection area can be expanded.

  Further, in FIG. 5A, the welding auxiliary plate 8 has a surface shape that follows the outer surface of the metal case 2. However, by providing a projection partly, for example, the resistance of the metal case 2 and the welding auxiliary plate 8 is provided. In welding, series projection welding is facilitated, and the entire surface of the welding auxiliary plate 8 on the metal case 2 side is not in contact with the outer surface of the metal case 2, but a gap is provided in part. Thus, for example, in the resistance welding between the metal case 2 and the welding auxiliary plate 8, a direct projection welding can be easily configured.

(Embodiment 2)
The second aspect of the present invention will be described below with reference to the second embodiment.

  6A to 6C are a plan view, a front view, and a bottom view showing a configuration of a capacitor used in the capacitor unit according to the second embodiment of the present invention. In FIG. 6, the same part numbers as those in FIGS. 1 to 5 are used for members having the same names installed in the same places as those in the first embodiment.

  In FIG. 6, reference numeral 10 is the same as the capacitor used in the first embodiment, and the positive and negative electrodes are taken out from the end face of the capacitor element 1 by the metal case 2 and the terminal plate 3. 1 shows the capacitor according to the first embodiment.

  Reference numeral 11 denotes a capacitor having a configuration in which the electrical polarity of the metal case 2 and the terminal plate 3 is opposite to that of the capacitor 10 of the first embodiment. Incidentally, the fact that the electrical polarity is opposite to that of the capacitor 10 of the first embodiment means that, for example, when the capacitor 10 of the first embodiment has the terminal plate 3 as the positive electrode and the metal case 2 has the negative electrode, In the capacitor 11, it means that the terminal plate 3 is a negative electrode, and the metal case 2 is a positive electrode.

  In the present embodiment, since the metal case 2 and the terminal plate 3 of the capacitor 11 have an electrical polarity opposite to that of the capacitor 10 of the first embodiment, the metal case 2 of the capacitor 11 of the second embodiment Although storing the capacitor element 1 stored in the reverse direction is mentioned, it is not limited thereto.

  In FIG. 6B, the portion indicated by a broken line on the side surface of the metal case 2 of the capacitor 10 and the capacitor 11 is a welding auxiliary plate 8, and the capacitor 10 and the capacitor 11 are formed by laser welding (welding mark 8 a). Each metal case 2 is welded to the side surface. The welding auxiliary plate 8 is preferably welded in advance before the capacitor is assembled in the same manner as in the first embodiment, and is preferably made of the same material as the metal case 2 from the viewpoint of the melting point when welding. .

  Reference numeral 12 denotes a connecting member. Since the connecting member 12 has a different polarity in the present embodiment when the capacitor 10 and the capacitor 11 are electrically connected, the connecting member 12 is connected via the welding auxiliary plate 8 on the side surface of the metal case 2. It is intended to fulfill. Further, the shape of the connecting member 12 is such that the side surface portion 12a that can be welded closely along the arc of the outer side surface of the metal case 2 in order to connect the respective welding auxiliary plates 8 of the capacitor 10 and the capacitor 11 to both ends. And has a flat portion 12b connecting the two side surface portions 12a therebetween. In addition, since the connection member 12 is connected to the welding auxiliary plate 8 by laser welding (welding mark 12c), the same material as the metal case 2 is preferable from the viewpoint of the melting point at the time of welding, but is not limited thereto.

  In the present embodiment, the side surfaces of the metal cases 2 are connected to each other. However, the connection method is not limited as long as the connection method does not cause a short circuit. For example, the connection between the welded portions 3c on the terminal plate 3 is not limited to this. The connection between the bottom surfaces of the metal case 2 is mentioned.

  In addition, when the welding mark 8a and the welding mark 12c overlap, the welding mark 8a that has been welded first is deformed, and therefore there is a problem that it is difficult to weld the connecting member 12 to be welded later. It is preferable that the mark 8a and the welding mark 12c do not overlap. Note that the welding shape is not limited to the shape shown in the drawing as long as the welding mark 8a and the welding mark 12c satisfy the condition that they do not overlap each other.

  The capacitor unit in the present embodiment has a configuration in which the capacitors 10 and the capacitors 11 are alternately connected in series.

  With the above configuration, the capacitor unit in the present embodiment is configured to laser weld the auxiliary welding plate 8 to a position where the connection member 12 is welded in advance before assembling the capacitor, and weld the connection member 12 thereon. As a result, as in the first embodiment, the welding conditions for welding the connection member 12 are widened, and the effect of improving the yield is obtained. Furthermore, since the shape of the connecting member 12 is simple, the manufacturing process can be shortened.

  In the embodiment, the case of laser welding is described as the welding method. However, the structure of the capacitor alone using the welding auxiliary plates 8 and 9 of the present invention is the capacitor connected to the metal case 2 to which the welding auxiliary plate 8 is connected in advance. After the element 1 is inserted and the opening of the metal case is sealed with the terminal plate 3 and the sealing rubber 6, the electrolytic solution is injected from the electrolytic solution injection hole provided in the terminal plate 3. Since it can be configured as a closed assembly process, it can be connected by resistance welding, arc welding (tungsten inert gas welding, metal inert gas arc welding, metal active gas welding, plasma welding, etc.), ultrasonic welding, etc. The degree of freedom of the configuration is remarkably widened, and the leakage can be suppressed from the viewpoint of reliability, and a dramatic effect that the connection area can be expanded can be obtained.

  Further, in FIG. 6A, the welding auxiliary plate 8 has a surface shape that follows the outer surface of the metal case 2. However, by providing a protrusion partly, the resistance of the metal case 2 and the welding auxiliary plate 8, for example. In the welding, series projection welding is facilitated, and the entire surface of the welding auxiliary plate 8 on the metal case 2 side is not in contact with the outer surface of the metal case 2, but a gap is provided on a part of the surface. Thus, for example, in resistance welding between the metal case 2 and the auxiliary welding plate 8, direct projection welding can be easily configured.

  According to the capacitor unit according to the present invention, it is possible to improve the working efficiency at the time of welding the connecting member and to improve the current resistance due to the expansion of the welding area, and to improve the yield at the time of manufacturing.

  As a result, it is expected to use a power source assist for automobiles that need to secure a connection area from the viewpoint of a backup power source for electronic devices and particularly a working current.

(A) In Embodiment 1 of this invention, the top view of the capacitor which comprises a capacitor unit, (b) The front sectional view, (c) The bottom view (A) The top view of the connection member which connects the capacitor which comprises a capacitor unit in Embodiment 1 of this invention, (b) The front view In Embodiment 1 of this invention, the front view of the state which welded the welding auxiliary plate beforehand to the metal case side surface of the capacitor which comprises a capacitor unit before an assembly. In Embodiment 1 of this invention, the top view of the state which welded the welding auxiliary plate beforehand to the plane part of the terminal board coupling | bond part of the capacitor which comprises a capacitor unit before an assembly. (A) The top view of the state which connected the capacitor which provided the welding auxiliary plate on the terminal board coupling | bond part in Embodiment 1 of this invention, and the capacitor which provided the welding auxiliary plate on the metal case side surface using the connection member, (B) Front view, (c) Bottom view (A) The top view of the state which connected the capacitor which the electrical polarity which the terminal board and metal case in Embodiment 2 of this invention have are mutually opposite, (b) The front view, (c) The bottom view (A) Top view of capacitor constituting conventional capacitor unit, (b) Front sectional view, (c) Bottom view (A) The top view of the state which the capacitor which comprises the conventional capacitor unit connected, (b) The front view, (c) The bottom view

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Metal case 2a, 3a Concave part 2b, 3b, 8a, 9a Weld trace 2c Curling process part 3 Terminal board 3c Welding part 4 Rubber stopper 5 Insulation member 6 Sealing rubber 7, 12 Connection member 7a Flat part 7b Vertical part 7c Side surface portion 8, 9 Welding auxiliary plate 8b Metal case side surface welding trace 9b Terminal plate outer surface side welding trace 10, 11 Capacitor

Claims (5)

A bottomed cylindrical metal case containing a capacitor element, and a terminal plate that seals the opening of the metal case, the terminal plate and the metal case having different polarities, and a capacitor With a plurality of capacitors arranged in parallel,
In a capacitor unit electrically connected by welding a terminal plate of one adjacent capacitor and a metal case of the other capacitor via a connecting member,
A capacitor unit in which a welding auxiliary plate is lap welded to the outer surface of the metal case, and the welding auxiliary plate and a connecting member are lap welded. A bottomed cylindrical metal case containing a capacitor element, and a terminal plate that seals the opening of the metal case, the terminal plate and the metal case having different polarities, and a capacitor With a plurality of capacitors arranged in parallel,
In the capacitor unit that is electrically connected by welding the metal cases of the adjacent capacitors via the connecting member,
A capacitor unit in which a welding auxiliary plate is lap welded to the outer side surfaces of the metal cases, and the welding auxiliary plate and a connection member are lap welded. The capacitor unit according to claim 1, wherein the terminal plate is provided with a welded portion having a flat portion protruding so as to be higher than a peripheral portion of the metal case. The capacitor unit according to claim 1, wherein a welding auxiliary plate is previously welded to a part of the outer surface of the terminal plate. The welding location of the welding auxiliary plate welded to the metal case and / or the terminal plate and the welding location of the connecting member welded on the welding auxiliary plate are different from each other. Capacitor unit.

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