JP2018078303A - Film capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a film capacitor which forms no opening portion between a metal laminate film and a bus-bar and which can suppress the worsening in capacitor characteristic such as the reduction in capacitance even when the bus-bar is configured to have a relatively large thickness in order to allow a large current to pass through the bus-bar; and a method for manufacturing the film capacitor.SOLUTION: A film capacitor comprises: a capacitor element; a bus-bar 4a connected to the capacitor element; and an exterior member formed by a metal laminate film 3 having, on one principal face thereof, a first resin layer 3a fronting the capacitor element, and covering the capacitor element and the bus-bar. Parts of the bus-bar are led out to outside the exterior member. In a lead-out part 30 of the exterior member, where parts of the bus-bar are led out from the exterior member, a second resin layer 6 containing an acid-modified resin is formed between the first resin layer and the bus-bar.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a film capacitor.

  In recent years, film capacitors have been used in electrical equipment, electronic equipment, particularly motor-driven inverter circuits.

  In the film capacitor used for this inverter circuit, development for miniaturization, high performance, and low cost is actively performed. In addition, since film capacitors used in inverter circuits are required to have a higher working voltage, higher current, and larger capacity, a plurality of capacitor elements connected in parallel are accommodated in the outer case, and the outer case A film capacitor with an outer case in which a mold resin is cast is developed and used.

  For example, as disclosed in Patent Document 1, a film capacitor in which a capacitor element is covered with a metal laminate film without using an outer case and a mold resin has been developed for the purpose of reducing the size and weight of the film capacitor. FIG. 13 is a sectional view showing the structure of this type of conventional film capacitor. The conventional film capacitor includes a polyvinylidene fluoride resin film 91, a vapor-deposited metal layer 92, electrodes 93a and 93b (corresponding to a metallicon electrode), external terminals 94a and 94b (corresponding to a bus bar), and a metal laminate film 95. The metal laminate film 95 includes a surface resin layer 95a, a metal layer 95b, and an inner surface resin layer 95c. Specifically, the surface resin layer 95a and the inner surface resin layer 95c include a plastic layer having a thickness of about 30 μm, and the metal layer 95b. Is made of aluminum having a thickness of about 40 μm.

  In this film capacitor, the capacitor element is formed by winding a pair of polyvinylidene fluoride resin films 91 having a metal such as aluminum, zinc, or an alloy thereof deposited on the surface as a deposited metal layer 92, and then winding both ends to draw out the electrodes. Electrodes 93a and 93b are formed by spraying a metal such as zinc on the surface. Further, external terminals 94a and 94b are connected and fixed to each electrode of the capacitor element. After that, the capacitor element is covered with the metal laminate film 95 in a state where the external terminals 94a and 94b are drawn out through the lead-out portion 930, the three sides are thermally welded and closed, and after the predetermined heat treatment, the remaining one side is covered. A film capacitor is formed by heat sealing and sealing the capacitor element with a metal laminate film 95.

JP 2009-94122 A

  In film capacitors used in HEVs (Hybrid Electric Vehicles) and EVs (Electric Vehicles), a large current often flows through the bus bar (external terminal), and therefore, it is necessary to use a bus bar having a relatively large thickness. The bus bar is drawn to the outside of the metal laminate film through the metal laminate film drawer, but when the thickness of the bus bar increases, the inner surface of the metal laminate film follows the bus bar surface at both ends in the width direction of the bus bar. It is difficult to make it adhere.

  FIG. 14 is a cross-sectional view taken along the cutting line II-II in FIG. As shown in FIG. 14, even if the lower laminate film 95x and the upper laminate film 95y are heat-sealed, the both ends of the width direction (W direction) because the thickness (H direction dimension) of the bus bar 94a (94b) is large. A slight gap (opening portion 100) is generated in the vicinity. As described above, with the technique described in Patent Document 1, it is difficult to completely seal the lower laminate film 95x, the upper laminate film 95y, and the bus bar 94a (94b) in the drawer portion 930 to seal the drawer portion. .

  Therefore, there is a high possibility that moisture will enter the inside of the metal laminate film 95 from the opening 100. Moisture that penetrates into the metal laminate film 95 and reaches the vapor deposition metal layer 92 oxidizes the vapor deposition metal layer 92. When the deposited metal layer 92 is oxidized, various capacitor characteristics such as a reduction in capacitance are caused.

  Therefore, the present invention suppresses the possibility that a mouth opening portion is generated between the metal laminate film and the bus bar even in a film capacitor using a bus bar having a large thickness, such as a film capacitor used in HEV or EV. An object of the present invention is to provide a film capacitor capable of suppressing a decrease in capacitor characteristics such as a decrease in capacitance, and a manufacturing method thereof.

  The first invention of the present application is formed of a capacitor element, a bus bar connected to the capacitor element, and a metal laminate film having a first resin layer on one main surface, and the first resin layer faces the capacitor element. In addition, an exterior member that covers the capacitor element and the bus bar is provided, a part of the bus bar is drawn out of the exterior member, and a part of the bus bar is pulled out from the exterior member. In the film capacitor, a second resin layer containing an acid-modified resin is formed between the first resin layer and the bus bar.

  A second invention of the present application is a method of manufacturing a film capacitor in which a capacitor element and a bus bar connected to the capacitor element are covered with an exterior member made of a metal laminate film having a first resin layer on one main surface. , A sticking step of sticking a resin sheet containing an acid-modified resin to the bus bar, and after the sticking step, a part of the bus bar is pulled out of the exterior member, and the first resin layer of the exterior member is a capacitor element So that the capacitor element and the bus bar are wrapped with an exterior member so that a part of the bus bar is pulled out of the exterior member, and an acid-modified resin is placed between the first resin layer and the bus bar at the drawer portion of the exterior member. A sealing step of sealing the lead-out portion by melting the resin sheet by heating in a state in which the resin sheet is included, forming a second resin layer containing the acid-modified resin A method of producing a film capacitor comprising a.

  A third invention of the present application is a method of manufacturing a film capacitor in which a capacitor element and a bus bar connected to the capacitor element are covered with an exterior member made of a metal laminate film having a first resin layer on one main surface. The acid-modified resin coating film is formed by coating the acid-modified resin powder on the bus bar by electrostatic coating to form an acid-modified resin coating film. After the acid-modified resin coating process, the acid-modified resin coating film is heated. After the acid-modified resin baking process for melting and forming an acid-modified resin baking coating film, and the acid-modified resin baking process, a part of the bus bar is pulled out of the exterior member, and the first resin layer of the exterior member is In the lead-out portion of the exterior member, the capacitor element and the bus bar are wrapped with the exterior member so as to face the capacitor element, and a part of the bus bar is pulled out of the exterior member. A sealing step of forming a second resin layer containing an acid-modified resin by sealing with an acid-modified resin baked coating film between the resin layer and the bus bar, and sealing the drawer portion; The manufacturing method of the film capacitor provided with these.

  According to the present invention, even in the case of a film capacitor using a thick bus bar capable of flowing a large current, it is possible to suppress the possibility of an opening portion between the metal laminate film and the bus bar. It is possible to suppress a decrease in capacitor characteristics such as a decrease in film capacitor capacity. In particular, when the present invention is used for applications requiring a large current such as HEV and EV, a greater effect can be obtained. Moreover, if the manufacturing method of this application is used, such a film capacitor can be manufactured easily.

It is a perspective view of the film capacitor of a 1st embodiment of the present invention. It is a perspective view of what removed the 3rd resin layer from the film capacitor of a 1st embodiment of the present invention. It is sectional drawing of the drawer part vicinity in 1st Embodiment of this invention. It is a figure explaining the sticking process in 1st Embodiment of this invention. It is a figure explaining the sealing process in 1st Embodiment of this invention. It is another figure explaining the sealing process in 1st Embodiment of this invention. It is sectional drawing of the drawer | drawing-out vicinity before heating and pressurizing in 1st Embodiment of this invention. It is a figure explaining the acid-modified resin coating process in 2nd Embodiment of this invention. It is sectional drawing of the drawer part vicinity in 3rd Embodiment of this invention. It is a perspective view of the film capacitor of 5th Embodiment of this invention. It is a figure explaining the state before folding in the sealing process in 5th Embodiment of this invention. It is a figure explaining folding in the sealing process in a 5th embodiment of the present invention. It is sectional drawing of the conventional film capacitor. It is sectional drawing of the drawer part vicinity of the conventional film capacitor.

(First embodiment)
Hereinafter, the configuration of the film capacitor and the manufacturing method thereof in the first embodiment will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a schematic configuration of a film capacitor 1 according to a first embodiment of the present invention. FIG. 2 is a perspective view in which the third resin layer 5 is removed from the film capacitor 1 of FIG. FIG. 3 is a partial cross-sectional view of the film capacitor 1 taken along a cutting line II in FIG.

  The film capacitor 1 includes a film capacitor element 2, a metal laminate film 3 covering the film capacitor element 2, and a pair of bus bars 4 (4a, 4a) extending from the film capacitor element 2 and extending to the outside of the metal laminate film 3. 4b). The metal laminate film 3 is an example of an exterior member.

  The metal laminate film 3 has a configuration in which an inner resin layer 3a, a metal layer 3b, and an outer resin layer 3c are laminated and integrated. As materials for the inner resin layer 3a, the metal layer 3b, and the outer resin layer 3c, polypropylene (hereinafter referred to as PP), aluminum, and nylon are used. Moreover, it has thickness of 80 micrometers, 40 micrometers, and 25 micrometers, respectively.

  Here, the configuration of the film capacitor element 2 will be described in detail based on the formation method. First, a pair of metallized films formed by vapor-depositing aluminum on at least one surface of a dielectric film made of PP or the like to form a vapor-deposited metal layer (vapor-deposited electrode) are overlapped and wound. Thus, a wound body is formed. Furthermore, this wound body is pressed and processed into a flat shape. Then, zinc is sprayed on the two opposing end surfaces of the deformed wound body to form a metallicon electrode, whereby the film capacitor element 2 is completed. As described above, the film capacitor element 2 has a flat shape, and has a configuration in which a capacitor portion with a vapor-deposited metal layer facing through a dielectric film is taken out to the outside through a metallicon electrode.

  The thickness of the bus bar 4, that is, the dimension of the bus bar 4 in the stacking direction of the lower laminate film 3 x and the upper laminate film 3 y (in FIG. 1) so that the film capacitor 1 can be used for an application requiring a large current such as HEV or EV. H direction) is 0.6 mm or more and 2.0 mm or less.

  One polarity of the vapor deposition electrode is connected to one end of the bus bar 4a through one metallicon electrode, and the other polarity of the vapor deposition electrode is connected to one end of the bus bar 4b through the other metallicon electrode. For example, soldering or resistance welding may be used as a method of connecting the bus bar 4a, the bus bar 4b, and the metallicon electrode.

  The metal laminate film 3 is composed of a lower laminate film 3x and an upper laminate film 3y, and is covered from above and below so as to enclose the film capacitor element 2 and the bus bar 4.

  A part of each bus bar 4 a, 4 b extends to the outside of the metal laminate film 3 through the drawer portion 30 of the metal laminate film 3. That is, a part of each bus bar 4 a, 4 b is exposed from the metal laminate film 3.

  As shown in FIG. 3, the bus bar 4a has a chamfered portion 4a1 by chamfering. When the bus bar 4a has the chamfered portion 4a1, the inner resin layer 3a of the metal laminate film 3 easily follows the surface shape of the bus bar 4a. Thereby, it can suppress that a clearance gap (opening part) generate | occur | produces between the bus-bar 4a and the inner side resin layer 3a of the metal laminate film 3. FIG.

  Further, a second resin layer 6 containing acid-modified PP is formed around the bus bar 4a so as to cover the bus bar 4a. That is, the second resin layer 6 is formed between the surface of the bus bar 4 a and the inner resin layer 3 a of the metal laminate film 3. The drawer portion 30 is sealed by the second resin layer 6 being in close contact with the inner resin layer 3a of the metal laminate film 3 and the surface of the bus bar 4a.

  As shown in FIG. 2, the bus bar 4 extends from the film capacitor element 2 and extends to the outside of the metal laminate film 3 beyond the outer edge 32 of the lead portion 30, and the second resin layer 6 extends from the outer edge 32 to the metal laminate. A protruding portion 61 that protrudes outside the exterior member formed of the film 3 is provided. That is, the protruding portion 61 is exposed from the metal laminate film 3. The protruding portion 61 can prevent the metal layer 3b of the metal laminate film 3 and the bus bar 4 from being short-circuited.

  Further, as shown in FIG. 1, the third resin covers the part of the exposed portion of the bus bar 4 from the metal laminate film 3, the part of the metal laminate film 3, and the protruding part 61 of the second resin layer 6. Layer 5 is formed. A total of two third resin layers 5 are attached to both sides of the bus bar 4 in the thickness direction (H direction in FIG. 1). The third resin layer 5 is made of a material different from that of the first resin layer 3 a and the second resin layer 6, and is arranged as a separate body from the first resin layer 3 a and the second resin layer 6. A polyimide tape can be used as the third resin layer 5, and is adhered to the metal laminate film 3, the bus bar 4 and the protruding portion 61 of the second resin layer 6 by an adhesive layer (not shown). As will be described later, the resin constituting the third resin layer 5 has a softening point of 220 ° C. or higher.

(Production method)
Below, the manufacturing method of the film capacitor 1 of 1st Embodiment is demonstrated.

(Attaching process)
The sticking process will be described with reference to FIG.

  First, aluminum is vapor-deposited on one side of a dielectric film made of PP to form a metallized film on which a vapor-deposited metal layer (vapor-deposited electrode) is formed. In this embodiment, aluminum is used as the vapor deposition metal as described above, but zinc, magnesium, or a mixture of these metals may be used.

  Next, the metallized film for one polarity and the metallized film for the other polarity are overlapped and wound with the end portions in the width direction being slightly shifted, and a long cylindrical wound body is produced. Then, the curved outer peripheral surface of the wound body is pressed from both sides in the radial direction of the wound body to be processed into a flat shape. Furthermore, the metallicon electrode 25 is formed by thermally spraying zinc on two mutually opposing end surfaces of the wound body 24 processed into a flat shape. Thereby, the film capacitor element 2 in which the capacitor portion facing the vapor deposition metal layer is formed through the dielectric film is completed. Next, one end of the bus bar 4a is connected to one metallicon electrode 25 by soldering, so that the bus bar 4a is electrically connected to one vapor deposition electrode via the one metallicon electrode 25. Similarly, the bus bar 4 b is electrically connected to the other polarity vapor deposition electrode via the other metallicon electrode 25. As shown in FIG. 4, the bus bar 4 a is connected to the metallicon electrode 25 at the soldering portion 28.

  Next, a resin sheet 6a is prepared. The resin sheet 6a is obtained by forming an acid-modified resin layer (not shown) on a base resin layer (not shown). The acid-modified resin layer is made of, for example, acid-modified PP. As shown in FIG. 4, the acid-modified resin layers of the resin sheet 6a are pressed against the both surfaces of the bus bar in the thickness direction one by one, and the resin sheet 6a is adhered. In addition, although the thing of the 2 layer structure of the base material resin layer and the acid-modified resin layer was used as the resin sheet 6a, it is not limited to this, For example, what mixed acid-modified resin in base resin is used. Can do. That is, if the resin sheet 6a contains an acid-modified resin, it is possible to reliably seal the drawer portion 30 in the sealing process described below.

(Sealing process)
Next, the sealing process will be described with reference to FIGS. First, a lower laminate film 3x and an upper laminate film 3y constituting the metal laminate film 3 are prepared. As shown in FIG. 5, the lower laminate film 3x and the upper laminate film 3y are formed with element accommodating portions (concave portions) 3x1 and 3y1 for accommodating the film capacitor elements 2 in the center portions thereof. As shown in FIG. 6, the film capacitor element 2 to which the bus bars 4a and 4b are connected is placed on the lower laminate film 3x so that the lower part of the film capacitor element 2 is accommodated in the element accommodating portion 3x1 of the lower laminate film 3x. Placed on. The dotted line in FIG. 5 depicts the bus bar 4a and the resin sheet 6a after placement as virtual lines. As shown in the dotted line of FIG. 5 and FIG. 6, the resin sheet 6a is located so as to protrude from the outer edge 32 of the lower laminate film 3x.

  Next, as shown by the arrows in FIG. 6, the upper laminate is formed on the film capacitor element 2 to which the bus bars 4a and 4b are connected so that the upper part of the film capacitor element 2 is accommodated in the element accommodating portion 3y1 of the upper laminate film 3y. Cover the film 3y. The resin sheet 6a is located so as to protrude from the outer edge 32 of the upper laminate film 3y.

  Through the above steps, the film capacitor element 2 and the bus bar 4 are wrapped from above and below by the lower laminate film 3x and the upper laminate film 3y, as indicated by arrows in FIG. At this time, a part of the bus bar 4 is drawn out of the metal laminate film 3 through the lead-out portion 30 of the metal laminate film 3.

  Next, a resin having a softening point of 220 ° C. or higher is prepared as the third resin layer 5. In the present embodiment, polyimide is used as the third resin layer 5, and more specifically, a polyimide tape having an adhesive layer (not shown) formed on one surface is used. As shown in FIG. 1, the polyimide tape is covered so as to cover part of the exposed portions of the bus bars 4a and 4b from the metal laminate film 3, part of the metal laminate film 3, and the resin sheet 6a protruding from the metal laminate film 3. A polyimide tape is attached using an adhesive layer. A total of two polyimide tapes 5 are bonded to each side of the bus bar 4 in the thickness direction (H direction in FIG. 1). That is, one polyimide tape 5 is attached to the edge 36a of the lower laminate film 3x and the bus bar 4, and the other polyimide tape 5 is attached to the edge 36a of the upper laminate film 3y and the bus bar 4.

  Next, the edge portions 36a, 36a, 36b, and 36b of the lower laminate film 3x and the upper laminate film 3y are sandwiched between the contact portions of the heat fusion machine in a state where the atmosphere is reduced, and heat fusion is performed by heating and pressurizing. Then, return to normal pressure. Thereby, the first resin layers of the lower laminate film 3x and the upper laminate film 3y are heat-sealed, and the four edge portions 36a, 36a, 36b, 36b become the four heat-sealed portions 36. In FIG. 2, dotted lines are provided for convenience in order to show the boundaries of 34 edge portions 36a, 36a, 36b, 36b.

  FIG. 7 is a cross-sectional view showing the laminated state of the bus bar 4, the resin sheet 6a, the metal laminate film 3, and the polyimide tape that is the third resin layer 5 before heating and pressurizing in the vicinity of the drawer portion 30. FIG. 3 is a cross-sectional view showing a state after heating and pressurizing in the vicinity of the drawer portion 30. By heating, the resin sheet 6 a becomes the second resin layer 6, the second resin layer 6 is formed around the bus bar 4, and the drawer portion 30 is sealed. As shown in FIG. 2, a part of the second resin layer 6 protrudes from the outer edge 32 of the opening 30, and the protrusion 61 is formed. In FIG. 2, the polyimide tape that is the third resin layer 5 is not shown in order to clearly show the state of the protruding portion 61. Actually, the protruding portion 61 is also covered with the third resin layer 5.

  Here, the thickness of the bus bar 4 is preferably 0.6 mm or more and 2.0 mm or less. If it is less than 0.6 mm, the gap (opening portion) 100 in FIG. 13 will not be formed, so the necessity of providing the second resin layer 6 is low. That is, if the bus bar has a thickness of 0.6 mm or more, the effect of the present invention can be enjoyed more greatly. Further, when the film capacitor of the first embodiment is used as a HEV or EV film capacitor, the thickness of the bus bar 4 is preferably 0.6 mm or more in order to allow a large current to flow.

  If the bus bar 4 has a thickness exceeding 2.0 mm, even if the second resin layer 6 is formed, the gap (opening portion) 100 in FIG. May be slightly inferior.

  The polyimide tape has a size that can cover all the protruding portions 61. Therefore, since the polyimide tape 5 is interposed between the protruding portion 61 of the second resin layer 6 and the contact portion of the heat-sealing machine, the protruding portion 61 contacts and adheres to the contact portion of the heat-sealing machine. There is no reduction in workability of the sealing process.

  In addition, although polyimide was used as resin which comprises the 3rd resin layer 5, it is preferable to comprise by the material which has a softening point of 220 degreeC or more. Since the heating temperature at the time of thermal fusion for thermally fusing the first resin layer 3a of the metal laminate film 3 is about 180 to 210 ° C, the third resin layer 5 has a softening point of 220 ° C or higher. If so, the third resin layer 5 will not be deformed or deteriorated during heat fusion. Therefore, it can prevent that the protrusion part 61 adheres to a contact part.

  Further, the presence of the protruding portion 61 can sufficiently ensure the creepage distance between the metal layer 3b exposed on the end face (cut surface) 29 (see FIG. 5) of the metal laminate film 3 and the bus bars 4a and 4b. A short circuit between the metal layer 3b and the bus bars 4a and 4b can be reliably prevented.

  As the resin sheet 6a, a two-layer structure of a base resin layer and an acid-modified resin layer was used, but when an acid-modified resin mixed with a base resin was used as the acid-modified resin sheet 6a, Similarly, after heating and pressurization, as shown in FIG. 3, the resin sheet 6a becomes the second resin layer 6, the second resin layer 6 is formed around the bus bar 4, and the drawer portion 30 is sealed.

  Through the above steps, the film capacitor 1 of the first embodiment is completed.

  In addition, in the sealing process described above, as shown in FIG. 7, a flat resin sheet 6 a was used that was adhered to both surfaces in the thickness direction of the bus bar 4 (short direction of the cross section of the bus bar). It is not limited to this. For example, you may use the bus bar provided with the cyclic | annular resin sheet. The annular resin sheet can be formed by the following manufacturing method. First, the flat resin sheet 6a is stuck on both surfaces in the thickness direction of the bus bar 4 (short direction of the cross section of the bus bar) in the state of the bus bar alone. Next, the resin sheet 6a is deformed so as to follow and closely adhere to the surface of the bus bar 4 by heating and pressurizing the bus bar with the resin sheet attached thereto by a press machine, thereby forming an annular resin sheet (annular resin member). Form. And the bus-bar 4 provided with the cyclic | annular resin sheet can be used in a sealing process by connecting the bus-bar which formed the cyclic | annular resin sheet with a metallicon electrode by soldering or resistance welding. Also according to this embodiment, the drawer portion can be reliably sealed by the second resin layer formed by the sealing step.

(Second Embodiment)
In the first embodiment, the resin sheet 6a is adhered to the bus bar 4, and is heat-sealed by being sandwiched between the metal laminate films 3 and heated and pressurized. However, the second embodiment is only used where the resin sheet 6a is not used. However, unlike the first embodiment, the other parts are the same, and therefore, differences from the first embodiment will be mainly described and description of common matters will be omitted.

(Acid-modified resin coating process)
As in the first embodiment, a film capacitor element 2 to which a bus bar 4 is attached is prepared. Next, as shown in FIG. 8, the acid-modified PP powder is charged and sprayed onto a predetermined position (corresponding to the lead-out portion) of the bus bar 4 by utilizing the electrostatic attraction force, thereby generating the acid-modified PP powder. The acid-modified resin coating film 6b is formed using electrostatic coating for depositing the body. As the electrostatic coating, a tribo (friction) charging method can be adopted. The number of currents when the negative charge of the gun flows to the ground by adjusting the screw speed (discharge amount control), main air pressure (conveyance pressure), and pressurized air pressure (charge amount control) of the electrostatic coating machine By setting it to about μA, for example, 2 μA, the acid-modified resin coating film 6b can be formed uniformly. The acid-modified PP powder is an example of an acid-modified resin powder. In addition, in order to prevent the coating from being performed more than necessary, it is preferable to perform masking by covering the mask.

  By using electrostatic coating, the acid-modified resin coating film 6b can be accurately and easily formed along the shape of the bus bar 4 over the entire surface of the exposed portion of the bus bar 4 that is the object to be coated. A large amount of processing can be performed.

(Acid-modified resin baking process)
Thereafter, the acid-modified resin coating film 6b is melted by heating to obtain an acid-modified resin baking coating film.

(Sealing process)
Next, as in the first embodiment, a second resin layer 6 containing acid-modified PP is formed between the bus bar 4 and the inner resin layer 3a of the metal laminate film 3 through a sealing process as shown in FIG. Is done. In addition, as shown in FIG. 2, a part of the second resin layer 6 protrudes from the outer edge 32 of the lead-out part 30, and a protrusion part 61 is formed.

(Third embodiment)
FIG. 9 shows a cross-sectional view of the vicinity of the lead portion 30 in the film capacitor of the third embodiment. In the second embodiment, as shown in FIG. 3, only the second resin layer 6 containing acid-modified PP is formed between the bus bar 4 and the inner resin layer 3 a of the metal laminate film 3.

  On the other hand, in the third embodiment, as shown in FIG. 9, in addition to the second resin layer 6, the fourth resin layer 7 is formed between the bus bar 4 and the inner resin layer 3 a of the metal laminate film 3. . The fourth resin layer 7 includes an epoxy resin, and is formed between the bus bar 4 and the second resin layer 6.

  In consideration of conductivity, the bus bar 4 is often formed of copper or a copper alloy, but the acid-modified PP contained in the second resin layer 6 may be accelerated by copper or a copper alloy. By forming the fourth resin layer 7 containing an epoxy resin between the bus bar 4 and the second resin layer 6 as in the present embodiment, the deterioration of the second resin layer 6 due to the copper or copper alloy bus bar 4 is prevented. Promotion can be suppressed.

  Below, the manufacturing method of 3rd Embodiment is demonstrated centering on a different process from 2nd Embodiment, and the description about a common matter is abbreviate | omitted.

(Epoxy resin layer forming process)
As in the first embodiment, a film capacitor element 2 to which a bus bar 4 is attached is prepared. Next, an epoxy resin liquid (a resin liquid partially containing an epoxy resin) is attached to a predetermined position (corresponding to the opening) of the bus bar 4. Examples of the method for adhering include application and screen printing. Next, by heating the epoxy resin liquid, the epoxy resin liquid is cured to form an epoxy resin layer as the fourth resin layer 7.

(Acid-modified resin coating process)
Next, masking is performed so that the surface of the fourth resin layer 7 is exposed and the surface of the bus bar 4 is not exposed, and then the exposed surface of the fourth resin layer 7 is covered so as to cover the exposed surface of the fourth resin layer 7. An acid-modified resin coating film is formed by electrocoating.

(Acid-modified resin baking process)
Thereafter, the acid-modified resin coating film is heated and melted to obtain an acid-modified resin baked coating film.

(Sealing process)
Next, in the same manner as in the first embodiment, the acid-modified resin baking coating film becomes the second resin layer 6 containing acid-modified PP through a sealing process, and is made of epoxy resin on the bus bar 4 as shown in FIG. The fourth resin layer 7, the second resin layer 6 containing acid-modified PP, and the inner resin layer 3a of the metal laminate film 3 are sequentially laminated. In addition, as shown in FIG. 2, a part of the second resin layer 6 protrudes from the outer edge 32 of the lead-out part 30, and a protrusion part 61 is formed.

(Fourth embodiment)
In the epoxy resin layer forming step of the third embodiment, the epoxy resin liquid is cured by attaching the epoxy resin liquid to a predetermined position of the bus bar 4 to heat the epoxy resin liquid as the fourth resin layer 7. Although formed, in the fourth embodiment, an epoxy resin powder was used without using an epoxy resin. In the following, the steps different from those of the third embodiment will be mainly described, and description of common matters will be omitted.

(Epoxy resin painting process)
An epoxy resin layer is formed using the electrostatic coating described in the acid-modified resin coating process of the second embodiment. First, in order to prevent the paint from being applied in an unnecessarily large range, it is preferable to perform masking with a mask. Next, the epoxy resin powder is charged and deposited on a predetermined position of the bus bar 4 (portion corresponding to the lead-out portion) using an electrostatic attraction force to form an epoxy resin coating film.

(Epoxy resin baking process)
Thereafter, the epoxy resin coating film is heated and melted to obtain an epoxy resin baked coating film.

  Subsequent steps are the same as those in the third embodiment, and a description thereof will be omitted.

  In addition, in 1st Embodiment, after the epoxy resin coating process of this embodiment is introduce | transduced before an adhesion | attachment process, an epoxy resin coating film is formed, and after forming an epoxy resin baking coating film by an epoxy resin baking process, The resin sheet 6a containing an acid-modified resin is stuck on the epoxy resin baked coating film by the sticking step, and the subsequent steps can be continued.

(Fifth embodiment)
A fifth embodiment will be described with reference to FIGS. In addition, it demonstrates centering on a process different from 1st Embodiment, and abbreviate | omits description about a common matter. In the film capacitor 1 of the fifth embodiment, the lead-out portion 30 is not formed at the edge portions 39a of the two metal laminate films 3x and 3y. The edge portions 39a of the two metal laminate films 3x and 3y are not heat-sealed, and the edge portion 39a of the laminate film 3 has a folded portion 39 that is folded so that the first resin layer 3a is exposed. doing. Below, a manufacturing method is demonstrated.

  First, two separate metal laminate films 3x and 3y are prepared. At the same time, the film capacitor element 2 to which the bus bar 4 is connected is prepared. The resin sheet 6a is stuck on the bus bar 4 as in the first embodiment.

(Sealing process)
The film capacitor element 2 to which the bus bar 4 is connected is placed on the lower laminate film 3x so that the lower part of the film capacitor element is accommodated in the element accommodating portion of the lower laminate film 3x. Next, the upper laminate film 3y is placed on the film capacitor element 2 to which the bus bar 4 is connected so that the upper part of the film capacitor element is accommodated in the element accommodating portion of the upper laminate film 3y. The bus bar 4 connected to the capacitor element 2 is wrapped with both laminate films 3x and 3y.

  Next, as shown in FIG. 11, four linear heat-sealing parts 36a, 36a, 36b, and 36b are formed using a heat-sealing machine. A straight dotted line in FIG. 11 is given for convenience in order to show the boundaries of the four fused portions 36a, 36a, 36b, 36b. The two heat fusion parts 36b are formed in the edge part 39a of the laminate films 3x and 3y. On the other hand, the two heat-sealing portions 36a are provided not at the edge portions 39a of the laminate films 3x and 3y but at positions closer to the center by a predetermined distance from the edge portions 39a. The resin sheet 6a is disposed between the two laminate films 3x and 3y at a portion corresponding to the two heat-sealed portions 36a before heat-sealing. Therefore, after the heat fusion, the second resin layer 6 is formed between the two laminate films 3x and 3y in the two heat fusion portions 36a.

  Next, as shown in FIG. 12, the inner end resin layer 3a, that is, the first resin layer is exposed to the outside of the laminate films 3x and 3y at the edge portion 39a located outside the heat fusion portion 36a. The folded portion 39 is formed by folding in the direction of the arrow. Thereby, the film capacitor 1 shown in FIG. 10 is completed.

  In the film capacitor 1 of the fifth embodiment, unlike the first embodiment, the outer edge 32 of the lead-out portion 30 from which the bus bar 4 is pulled out from the laminate film 3 is not the outer edge 34 of the laminate films 3x and 3y. That is, with this configuration, it is possible to suppress the possibility that the bus bar 4 and the metal layer 3b of the laminate films 3x and 3y are short-circuited. In addition, since there is no possibility that the bus bar 4 and the metal layer 3b of the laminate films 3x and 3y are short-circuited, it is not necessary to provide the protruding portion 61 of the second resin layer 6. Furthermore, it is not necessary to form the third resin layer 5 that prevents the protruding portion 61 and the contact portion of the heat-sealing machine from sticking.

  As described above, in the configuration of the conventional film capacitor, as shown in FIG. 14, even if the lower laminate film 95x and the upper laminate film 95y are heat-sealed, the bus bar 94a (94b) is thick. A slight gap (opening portion) 100 is generated in the vicinity of both ends of W. Therefore, it is difficult to completely seal the drawer portion 930 by bringing the lower laminate film 95x, the upper laminate film 95y, and the bus bar 94a (94b) into close contact with each other in the drawer portion 930.

  Therefore, moisture permeates into the inside of the metal laminate film 95 from the opening portion 100, causing the vapor deposition electrodes 93a and 93b to be oxidized, and various capacitor characteristics such as a reduction in capacitance are deteriorated.

  On the other hand, according to the present invention, the second resin layer 6 containing an acid-modified resin is formed between the bus bar 4 having a large thickness and the inner resin layer 3a of the metal laminate film 3 as shown in FIG. . Therefore, there is no possibility that a mouth opening portion is generated in the drawer portion 30, and there is no possibility that moisture enters the inside of the metal laminate film 3. Therefore, oxidation of the vapor deposition electrode does not occur, and deterioration of various capacitor characteristics such as capacity reduction can be suppressed. Therefore, the present invention can be suitably applied to a film capacitor or the like used for, for example, HEV or EV, which requires the use of a bus bar 4 having a large thickness.

  In the first to fourth embodiments, the third resin layer 5 is formed, but the third resin layer 5 is not necessarily required.

  In addition, the bus bars 4a and 4b extend from the lead-out portions 30 provided on the two opposite sides of the outer periphery of the metal laminate film 3, but the two bus bars 4a and 4b are on one side of the laminate film 3. It is good also as a structure extended from the provided drawer | drawing-out part.

  In the fifth embodiment, the folded portion 39 is preferably folded 180 degrees at the edge 32 of the drawer portion 30, but is not necessarily limited thereto. If it turns back 90 degrees or more, it has the effect of suppressing a short circuit between the metal layer 3b of the metal laminate film 3 and the bus bar 4.

  In the first to fifth embodiments, as a film capacitor element, a flat wound body in which a metallized film for one polarity and a metallized film for the other polarity are overlapped and wound is used. Not. It is also possible to use a laminated film capacitor element in which a plurality of metallized films for one polarity and a metallized film for the other polarity are alternately laminated without being wound. Further, a structure in which a plurality of film capacitor elements connected in parallel to a bus bar may be covered with a metal laminate film.

  The film capacitor according to the present invention does not cause a mouth opening between the metal laminate film and the bus bar even if a bus bar having a relatively large thickness is used to allow a large current to flow through the bus bar. It is possible to suppress a decrease in capacitor characteristics such as a decrease in capacitance. In particular, in a film capacitor used for HEV or EV, a large current flows through the bus bar, that is, a bus bar having a relatively large thickness is often used.

  Moreover, according to the film capacitor manufacturing method of the present invention, the film capacitor of the present invention can be manufactured easily and efficiently.

DESCRIPTION OF SYMBOLS 1 Film capacitor 2 Film capacitor element 3 Metal laminate film 3a Inner resin layer (1st resin layer)
3b Metal layer 3c Outer resin layer 4, 4a, 4b Bus bar 5 Third resin layer 6 Second resin layer 7 Fourth resin layer 30 Drawer part 32 Outer edge 34 Outer edge 36a, 36b Edge end part 39 Folded part 61 Protruding part 100 Gap ( Mouth opening)

Claims (7)

A capacitor element;
A bus bar connected to the capacitor element;
Formed of a metal laminate film provided with a first resin layer on one main surface, the first resin layer facing the capacitor element, and an exterior member covering the capacitor element and the bus bar,
A part of the bus bar is drawn out of the exterior member,
A part of the bus bar is pulled out from the exterior member, and a second resin layer containing an acid-modified resin is formed between the first resin layer and the bus bar in the drawer portion of the exterior member,
Provided with a layer containing an epoxy resin in a part between the bus bar and the second resin layer,
Film capacitor.   The film capacitor according to claim 1, wherein the bus bar is made of copper or a copper alloy.   3. The film capacitor according to claim 1, wherein the second resin layer has a protruding portion that protrudes from an outer edge of the drawer portion to the outside of the exterior member.   The drawer part is not formed at the edge part of the exterior member, the edge parts are not heat-sealed, and the edge part of the exterior member exposes the first resin layer, respectively. The film capacitor according to claim 1, wherein the film capacitor is folded back.   The film capacitor according to claim 1, wherein the second resin layer includes acid-modified polypropylene.   The film capacitor according to claim 1, wherein the bus bar has a thickness of 0.6 mm to 2.0 mm.   The film capacitor according to claim 1, wherein the bus bar has a chamfered portion in the drawer portion.

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