JP2013251351A - Capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat dissipation of a capacitor.SOLUTION: A capacitor 15 includes a plurality of film capacitors 1 connected in parallel. A first metallikon part 6 of each film capacitor 1 is connected to a plate-like copper bar 9 connected to a positive electrode of a DC source, and a second metallikon part 6 of each film capacitor 1 is connected to a plate-like copper bar 10 connected to a negative electrode of the DC source. The film capacitors 1 are disposed on the copper bar 10 so that the surfaces of the metallikon parts 6 of the film capacitors 1 are arranged perpendicular to the plate surfaces of the copper bars 9 and 10. When a film capacitor group 11 is composed, four film capacitors 1 are adjacently disposed so that the first metallikon parts 6 connected to the positive electrode and the second metallikon parts 6 connected to the negative electrode are arranged away from and opposite to each other. Two film capacitor groups 11 having such a structure are stacked so as to be adjacent to each other in a short axis direction of the metallikon parts 6 of the film capacitors 1 which structure the film capacitor groups 11.

Description

  The present invention relates to a capacitor in which a plurality of unit capacitors are connected in parallel.

  A film capacitor is used as a smoothing capacitor for an inverter circuit for a motor of a hybrid vehicle or an electric vehicle (for example, Patent Documents 1 to 3). In this application, there is a high demand for downsizing and increasing the current of the capacitor.

JP 2008-270329 A JP 2011-101042 A JP 2007-81007 A

  However, when the capacitor is further reduced in size and increased in current, the self-heating amount of the capacitor increases and the life of the capacitor is shortened.

  In view of the above circumstances, an object of the present invention is to provide a technique that contributes to an improvement in heat dissipation of a capacitor.

  One aspect of the capacitor of the present invention that achieves the above object is to wind a pair of metal vapor deposition films in which metal vapor deposition electrodes are formed on one side of a dielectric film, and to wind both ends perpendicular to the winding axis of the winding body. A plurality of film capacitors provided with a flat elliptical extraction electrode on the surface, a plate-shaped first electrode terminal to which one extraction electrode of the film capacitor is connected, and the other extraction electrode of the film capacitor are connected A plate-like second electrode terminal, wherein a long diameter of the extraction electrode of the film capacitor is formed to be equal to a length of one side of the plate surface of the first electrode terminal, and the plate of the first electrode terminal The film capacitor is arranged so that the minor axis of the extraction electrode surface is perpendicular to the surface, and the extraction electrode surface connected to the positive electrode and the extraction electrode surface connected to the negative electrode are spaced apart from each other. next to It is characterized by composing the film by placing a capacitor between film capacitor group to be.

  Another aspect of the capacitor of the present invention that achieves the above object is characterized in that in the above capacitor, the film capacitor group is stacked in the minor axis direction of the extraction electrode of the film capacitor constituting the film capacitor group. It is said.

  Further, in another aspect of the capacitor of the present invention that achieves the above object, in the above capacitor, between the extraction electrode of the film capacitor and the extraction electrode of another film capacitor facing away from the extraction electrode, A sheet-like insulator is provided.

  In another aspect of the capacitor of the present invention that achieves the above object, in the capacitor, the plate surface of the first electrode terminal and the plate surface of the second electrode terminal are overlapped via an insulating sheet, A film capacitor group is stacked on the plate surface of the first electrode terminal.

  Another aspect of the capacitor of the present invention that achieves the above object is characterized in that in the above capacitor, the dielectric film contains polyetherimide.

  In another aspect of the capacitor of the present invention that achieves the above object, in the above capacitor, the dielectric film is a polyetherimide film having a dielectric loss tangent at 200 ° C. of 0.005 or less. .

  Another aspect of the capacitor of the present invention that achieves the above object is a plate-like structure in which a plurality of unit capacitors each having an extraction electrode formed on a pair of opposing surfaces and one extraction electrode of the unit capacitor are connected. A first electrode terminal of the unit capacitor and a plate-like second electrode terminal to which the other extraction electrode of the unit capacitor is connected, wherein the long side of the extraction electrode of the unit capacitor is connected to the first electrode. An extraction electrode surface formed equal to the length of one side of the plate surface of the terminal, the unit capacitor being disposed so that the extraction electrode surface is perpendicular to the plate surface of the first electrode terminal, and connected to the positive electrode The unit capacitor group is configured by arranging adjacent unit capacitors so that the surface of the electrode and the extraction electrode surface connected to the negative electrode are spaced apart from each other.

  According to the above invention, it can contribute to the improvement of the heat dissipation of a capacitor | condenser.

It is a figure which shows the winding type film capacitor used for the capacitor | condenser which concerns on embodiment of this invention, (a) An exploded view of a winding type film capacitor, (b) It is a perspective view of a winding type film capacitor. . 1 is a perspective view of a film capacitor according to an embodiment of the present invention. (A) Perspective view of capacitor of Reference Example 1 (before epoxy resin casting), (b) Perspective view of capacitor of Reference Example 1 (after epoxy resin casting). 6 is an exploded perspective view of a capacitor of Reference Example 1. FIG. It is the characteristic view which showed the relationship of L, H, and Sa of the film capacitor which concerns on Example 1 of this invention, and the film capacitor which concerns on the reference examples 1 and 2. FIG. 10 is a perspective view of a capacitor of Reference Example 2. FIG. It is a perspective view of the capacitor | condenser which concerns on Example 1 of this invention. It is a perspective view of the capacitor | condenser which concerns on Example 2 of this invention. It is a perspective view of the capacitor | condenser which concerns on Example 3 of this invention. It is a characteristic view which shows the time change of the electrostatic capacitance in 200 degreeC of the film capacitor which concerns on Example 4 of this invention.

  A capacitor according to an embodiment of the present invention will be described in detail with reference to the drawings. In the description of the embodiment, a winding type film capacitor (hereinafter referred to as a film capacitor) is used, and a capacitor configured by connecting the film capacitors in parallel will be described as an example. The principle of the film capacitor is that when a voltage is applied between the electrodes, the dielectric film sandwiched between the electrodes is polarized by an electrostatic induction action and charges are stored.

  FIG. 1A is an exploded view of the film capacitor according to the embodiment of the present invention, and FIG. 1B is a perspective view of the film capacitor according to the embodiment of the present invention.

  As shown in FIG. 1A, a film capacitor 1 has a set of metal vapor deposition films 4 in which a metal layer 3 such as aluminum or zinc is vapor-deposited on one surface of a dielectric film 2. Two metal vapor deposition films 4 are overlapped so that the metal layer 3 formed on each metal vapor deposition film 4 is not in contact with each other, and wound around a winding core 5. After winding the metal vapor-deposited film 4, the winding core 5 is pulled out, and a metal such as zinc is sprayed onto the surface formed perpendicular to the winding axis (by metallicon), and the metallicon portion 6 (collection) is collected on the film capacitor 1. Electrical part) is formed.

  As shown in FIG. 1B, the external appearance of the film capacitor 1 is a flat elliptic columnar shape, and one flat elliptical surface (metallicon portion 6) is electrically connected to the metal layer 3 deposited on one metal vapor-deposited film 4. The other flat elliptical surface (metallicon portion 6) is electrically connected to the metal layer 3 deposited on the other metal vapor deposition film 4. In the film capacitor 1, the shape (area, thickness) of the dielectric film 2 is determined so that the capacitance necessary for the film capacitor 1 can be obtained. The metal layer 3 deposited on the dielectric film 2 functions as an electrode of the film capacitor 1. If the shape of the metal layer 3 deposited on the dielectric film 2 is a lattice, the deposited metal layer 3 functions as a fuse.

  As shown in FIG. 2, each metallicon part 6 of a general film capacitor 1 has two connection parts 6 c and 6 c for connecting the metallicon part 6 and electrode terminals electrically connected to the metallicon part 6. Provided. The lead wire 7 and the like are soldered to the connection portion 6c.

[Reference Example 1]
FIG. 3A shows a capacitor 8 according to Reference Example 1. As shown in FIG. 3A, the capacitor 8 according to Reference Example 1 has eight film capacitors 1a, and one metallicon portion 6a of each film capacitor 1a is a plate connected to the positive electrode of the DC power source. The other metallicon part 6a of each film capacitor 1a is connected to a plate-like copper bar 10 connected to the negative electrode of the DC power source. The metallicon part 6a of the film capacitor 1a and the copper bar 9 (or copper bar 10) are electrically connected via the lead wire 7 to form a current collecting structure of the film capacitor 1a.

  The film capacitor 1a is provided so that the surface of the metallicon portion 6a is perpendicular to the plate surfaces of the copper bars 9 and 10. At this time, the opposing surface between the side surface of the film capacitor 1a (the surface of the film capacitor 1a and the surface perpendicular to the metallicon portion 6a: the side surface of the flat elliptical column) and the plate surface of the copper bars 9 and 10 is widened. The film capacitor 1a is provided on the copper bar (or copper bar 10). Further, four adjacent film capacitors 1a are arranged so that the metallicon portion 6a connected to the positive electrode and the metallicon portion 6a connected to the negative electrode are spaced apart and constitute a film capacitor group 11a. The two film capacitor groups 11a and 11a configured as described above are arranged so as to be adjacent to each other in the major axis direction of the metallicon portion 6a constituting the film capacitor group 11a.

The copper bars 9 and 10 are stacked via the insulating sheet 12. By making the copper bars 9 and 10 into a plate shape, the inductance of the entire capacitor 8 can be reduced. The copper bar 9 is provided with a P terminal 9 _P , a U terminal 9 _U , a V terminal 9 _V , and a W terminal 9 _W , and the copper bar 10 has an N terminal 10 _N , a U terminal 10 _U , a V terminal 10 _V , A W terminal 10 _W is provided. As shown in FIG. 4, the copper bar 10 is formed with a groove 10 a through which the lead wire 7 connecting the metallicon part 6 and the copper bar 9 of each film capacitor 1 passes.

  As shown in FIG. 3 (b), the film capacitor 1a connected to the copper bars 9 and 10 is housed in a case 13, and an insulator such as epoxy resin is cast in the case 13 (also in other embodiments). The same). In this way, intrusion of moisture and oxygen into the film capacitor 1 is prevented, and oxidation degradation of the film capacitor 1a is prevented.

  In the capacitor 8 in which a plurality of film capacitors 1a are connected in parallel, the heat transfer path of the film capacitor 1a is a path (path 1) that is transmitted to the outside air via the epoxy resin, and the outside air via the lead wire 7 and the copper bars 9 and 10. Two routes (route 2) are considered.

  In order to improve the heat dissipation of the film capacitor 1a, it is conceivable to improve the heat dissipation amount of these two paths. Therefore, as a method for improving the heat dissipation of the path 1, the shape of the film capacitor 1 in which the surface area of the film capacitor 1a is increased was examined. Moreover, as a method of improving the heat dissipation of the path 2, a method of arranging the film capacitor 1a with respect to the copper bars 9, 10 so that the area of the copper bars 9, 10 facing the side surface of the film capacitor 1a is increased, A method of arranging the film capacitor 1a with respect to the copper bars 9 and 10 was studied so that the lead wire 7 connecting the film capacitor 1a and the copper bars 9 and 10 was shortened.

[Examination of surface area of film capacitor]
First, when the volume of the film capacitor 1 is obtained from the capacitance of the film capacitor 1 shown in FIG. 1B, the volume V of the film capacitor 1 is expressed by the equation (1).
V = Sd = Cd ² / ε ₀ ε _r (1)
C: Capacitance of the film capacitor, S: Area of the dielectric film, d: Thickness of the dielectric film, ε ₀ : Dielectric constant of vacuum, ε _r : Relative permittivity of the dielectric film From the equation (1), The volume V of the film capacitor 1 is defined by the capacitance of the film capacitor 1 and the thickness of the dielectric film 2. Since the capacitance of the film capacitor 1 provided in the capacitor is predetermined, the capacitance C is constant. If a constant dielectric film 2 is used regardless of the shape of the film capacitor 1, the thickness d of the dielectric film 2 is constant, and the volume of the film capacitor 1 is constant regardless of the shape of the film capacitor 1. .

The film capacitor 1 can be approximated to a solid in which a pair of semi-cylinders are provided at both ends of a prism. Therefore, the volume V of the film capacitor 1 is represented by the formula (2).
V = πr ² H + 2rLH (2)
r: radius of semicircle, H: height of film capacitor, L: distance (width) between centers of semicircles
Moreover, the surface area Sa of the film capacitor 1 is shown by Formula (3).
Sa = 2πr ² + 2πrH + 2LH + 4rL (3)
Therefore, when the volume V of the film capacitor 1 is constant, the surface area Sa of the film capacitor 1 can be expressed as a function of the width L and the height H of the film capacitor 1 from the expressions (2) and (3).

  FIG. 5 is a characteristic diagram showing the relationship between the shape of the film capacitor 1 and the surface area Sa. In the characteristic diagram of FIG. 5, it is shown that the surface area Sa of the film capacitor 1 is larger as the concentration is higher. As apparent from FIG. 5, the surface area Sa of the film capacitor 1 can be increased by increasing the width L and height H of the film capacitor 1.

  However, the size of the capacitor cannot be increased from the current level due to the demand for miniaturization of the capacitor. Therefore, the width L and height H of the film capacitor 1 are limited by the size of the case that houses the film capacitor 1. Moreover, the width L and height H of the film capacitor 1 are also limited by the arrangement of the film capacitor 1 with respect to the copper bar.

  Then, the arrangement | positioning form of the film capacitor with respect to a copper bar and the shape of a film capacitor were examined by comparing the capacitor | condenser of (1)-(4) which connects eight film capacitors in parallel with respect to a copper bar.

  The capacitor (1) is formed on the copper bar 9 so that the metallicon part 6b surface of the film capacitor 1b is parallel to the plate surfaces of the copper bars 9, 10 as shown in FIG. The film capacitor 1b is disposed on (or on the copper bar 10), and the width L of the film capacitor 1b is increased as much as possible.

  The capacitor of (2) has a configuration in which the film capacitor is arranged on the copper bar so that the metallicon part surface of the film capacitor is parallel to the plate surface of the copper bar, and the height H of the film capacitor is increased as much as possible. Yes (not shown).

  The capacitor (3) is formed on the copper bar 9 so that the metallicon part surface 6 of the film capacitor 1 is perpendicular to the plate surfaces of the copper bars 9, 10 as shown in FIG. The film capacitor 1 is arranged on (or on the copper bar 10), and the width L of the film capacitor 1 is increased as much as possible.

  The capacitor of (4) has a configuration in which the film capacitor is arranged on the copper bar so that the metallicon part surface of the film capacitor is perpendicular to the plate surface of the copper bar, and the height H of the film capacitor is increased as much as possible. Yes (not shown).

Among the capacitors (1) to (4), the capacitor having the largest surface area (surface area 0.0133 m ² ) of the film capacitor constituting the capacitor was the capacitor (3). Accordingly, assuming that the capacitor (3) has the best heat dissipation performance of the path 1, the heat dissipation performance of the path 2 was examined using this capacitor.

[Examination of film capacitor placement on copper bar]
Comparing the capacitors of Examples 1 to 3 configured using the film capacitor 1 having the largest surface area, the path 2 (path through which heat is released to the outside air via the lead wire 7 and the copper bars 9 and 10) ) Was studied.

[Example 1]
FIG. 7 shows a capacitor 15 according to the first embodiment. The capacitor 15 of Example 1 is the same as the capacitor 8 of Reference Example 1 except that the shape of the film capacitor 1 and the stacking direction of the film capacitor 1 are different from those of the capacitor 8 of Reference Example 1. Therefore, only parts different from the capacitor 8 of the reference example 1 will be described in detail, and parts common to the capacitor 8 of the reference example 1 are denoted by the same reference numerals and detailed description thereof will be omitted.

  As shown in FIG. 7, the capacitor 15 according to the first embodiment includes eight film capacitors 1 and plate-like copper bars 9 and 10.

  The film capacitor 1 is formed so that the long diameter of the metallicon portion 6 is substantially equal to the length of one side of the plate surface of the copper bar 9 (and the copper bar 10) (the same applies to the capacitors of Examples 2 and 3). In other words, the long diameter of the metallicon part 6 is formed substantially equal to one side of the case 13 that houses the film capacitor 1.

  The copper bars 9 and 10 are stacked via the insulating sheet 12. The film capacitor 1 is provided on the copper bar 10 so that the metallicon part 6 surface is perpendicular to the plate surfaces of the copper bars 9 and 10. One metallicon part 6 of each film capacitor 1 is connected to a copper bar 9, and the other metallicon part 6 is connected to a copper bar 10. Then, the film capacitor group 11 is configured by arranging four adjacent film capacitors 1 so that the metallicon portion 6 connected to the positive electrode and the metallicon portion 6 connected to the negative electrode are spaced apart from each other. The two film capacitor groups 11 configured in this way are arranged so as to be adjacent to each other in the minor axis direction of the metallicon part 6 of the film capacitor 1 constituting the film capacitor group 11.

[Example 2]
FIG. 8 shows a capacitor 16 according to the second embodiment. In the capacitor 16 according to the second embodiment, the distance between the lead wires 7 connecting the copper bars 9 and 10 and the film capacitors 1 is shortened, and the copper bars 9 and 10 facing the side surfaces of the film capacitor 1 are shortened. Each film capacitor 1 is arranged with respect to the copper bars 9 and 10 so that the area is widened. The capacitor 16 according to the second embodiment is the same as the capacitor 15 according to the first embodiment except that the shape of the copper bar 9 and the arrangement form of the flum capacitor 1 with respect to the copper bars 9 and 10 are different. Therefore, only the shape of the copper bar 9 and the arrangement form of the copper bars 9 and 10 will be described in detail, and the other portions are the same as those in the first embodiment, and thus detailed description thereof is omitted.

  The capacitor 16 according to the second embodiment includes eight film capacitors 1 and copper bars 9 and 10.

  The film capacitor 1 is provided so that the metallicon portion 6 surface is perpendicular to the plate surfaces of the copper bars 9 and 10. Further, the film capacitor group 11 is configured by arranging four adjacent film capacitors 1 so that the metallicon part 6 connected to the positive electrode and the metallicon part 6 connected to the negative electrode are spaced apart from each other. The two film capacitor groups 11 configured in this way are arranged so as to be adjacent to each other in the minor axis direction of the metallicon part 6 of the film capacitor 1 constituting the film capacitor group 11.

  The copper bar 9 includes plate-like copper bars 9a and 9b provided by sandwiching stacked film capacitor groups 11 in the stacking direction, and a connection portion 9c for electrically connecting the copper bars 9a and 9b. Have The copper bar 10 is provided between the film capacitor groups 11 and 11.

[Example 3]
FIG. 9 shows a capacitor 17 according to the third embodiment. In the capacitor 17 according to the third embodiment, the film capacitors 1 are arranged with respect to the copper bars 9 and 10 so that the distance between the lead wires 7 connecting the copper bars 9 and 10 and the film capacitors 1 is shortened. It is. The capacitor 17 according to the third embodiment is the same as the capacitor 15 according to the first embodiment except that the arrangement form of the film capacitor 1 with respect to the copper bars 9 and 10 is different. Therefore, only the arrangement form of the film capacitor 1 with respect to the copper bars 9 and 10 will be described in detail, and the other portions are the same as those in the first embodiment, and thus detailed description thereof is omitted.

  The capacitor 17 according to the third embodiment includes eight film capacitors 1 and copper bars 9 and 10.

  The film capacitor 1 is provided so that the metallicon portion 6 surface is perpendicular to the plate surfaces of the copper bars 9 and 10. Further, the film capacitor group 11 is configured by arranging four adjacent film capacitors 1 so that the metallicon part 6 connected to the positive electrode and the metallicon part 6 connected to the negative electrode are spaced apart from each other. The two film capacitor groups 11 configured in this way are arranged so as to be adjacent to each other in the minor axis direction of the metallicon part 6 of the film capacitor 1 constituting the film capacitor group 11.

  The copper bars 9 and 10 are stacked via the insulating sheet 12 and arranged between the film capacitor groups 11 and 11.

  Table 1 shows the capacitance and dimensions of the capacitor 8 of Reference Example 1 and the capacitors 15, 16, and 17 of Examples 1 to 3. In the following description, the descriptions of the capacitors 8, 15, 16, 17 and the film capacitors 1, 1a are omitted.

(Capacitor evaluation)
A film capacitor generates heat due to a ripple current, and the temperature rises. Therefore, the heat generation condition of the ripple current was given to the film capacitor, and the temperature distribution in the capacitor was analyzed from the simulation. Further, the maximum temperature rise (ΔT) of the capacitor was calculated based on the heat generation condition of the ripple current and the simulation result.

The temperature distribution in the capacitor was analyzed by giving a heat generation condition of a temperature rise due to a ripple current under normal use conditions (frequency: 14 kHz, effective current: 80 A). At this time, the external environment of the condenser was cooled by natural convection. Incidentally, the calorific value J _r by ripple current was calculated based on the equation (4).
J _r = 2πfCV ² tan δ (4)
f: frequency, C: capacitance of the film capacitor, V: effective voltage, tan δ: dielectric loss tangent of the film capacitor Further, the inductance of the film capacitor constituting the capacitor and the inductance of the entire capacitor were calculated by simulation. Table 2 shows the results calculated based on the simulation.

  As shown in Table 2, in the capacitors of Reference Example 1 and Examples 1 to 3, the temperature of the capacitor increased due to the ripple current. The maximum temperature rise (ΔT = internal temperature−outside temperature) was observed at the center of each film capacitor. Compared with the capacitor of Reference Example 1, it can be seen that the capacitors of Examples 1 to 3 suppress the maximum temperature rise (ΔT) by 31 to 33%. In other words, by increasing the surface area of the film capacitor constituting the capacitor, the heat dissipation of the film capacitor was improved, and as a result, the heat dissipation of the capacitor could be improved.

  Moreover, when Examples 1-3 are compared, the maximum temperature rise is reducing by changing the arrangement | positioning form of a copper bar. However, since this reduction amount is slight, it is considered that the heat dissipation path of the capacitor mainly depends on the surface area of the unit capacitor (film capacitor).

  The inductance per film capacitor is increased by changing the shape of the film capacitor so that the surface area of the film capacitor is increased. As is clear from the comparison between the capacitor of Reference Example 1 and the capacitors of Examples 2 and 3, the inductance of the entire module is increased due to the increase in inductance per film capacitor.

  In contrast, when comparing the capacitor of Example 1 and the capacitor of Reference Example 1, the capacitor of Example 1 has an increased inductance per film capacitor, but the inductance of the entire capacitor is that of Reference Example 1. It is lower than the capacitor. This is because the positive copper bar and the negative copper bar are provided close to each other, and the film capacitor is provided so that the four lead wires are close to each other. This is thought to be a reduction in inductance. That is, the capacitor of Example 1 had higher heat dissipation than the capacitor of Reference Example 1, and the inductance of the entire capacitor was low.

Since the inductance of the entire capacitor causes an increase in surge voltage, it is required to reduce the inductance of the entire capacitor. The surge voltage Es is expressed by equation (5).
Es = −L × (di / dt) (5)
L: inductance of the entire capacitor, di / dt: time variation of current It can be seen that the surge voltage Es increases as the current changes greatly in a short time and as the circuit inductance increases. For example, when the switching element is an IGBT (Insulated Gate Bipolar Transistor), the time change (di / dt) of the current is di / dt = 5.0 × 10 ^{8 for the} Si semiconductor and di / dt = 1.0 for the SiC semiconductor. × 10 ¹⁰ That is, when the capacitors of Reference Example 1 and Examples 1 to 3 are applied to an inverter composed of switching elements using SiC (silicon carbide), a surge voltage of 150 to 300 V is expected to be generated.

[Example 4]
The capacitor according to the fourth embodiment is a capacitor intended to correspond to a SiC inverter using a SiC element that performs high-speed switching.

  The SiC element can be operated at a high temperature, for example, an operation at 200 ° C. or higher has been reported. Therefore, heat resistance of 200 ° C. or higher is also required for the film capacitor constituting the capacitor used in the SiC inverter. The inventors diligently studied the dielectric film forming the film capacitor, and adopted polyetherimide (PEI) as a material used for the dielectric film. The PEI film is a dielectric film that has high heat resistance and is less expensive than other heat resistant films. With respect to this PEI film, the film characteristics required for the film capacitor, which are heat resistance, electrical characteristics, and affinity with the deposited metal, were examined.

(1) Examination of heat resistance Regarding the heat resistance, the heat resistant temperature of the PEI film must be higher than the sum of the environmental temperature of the capacitor and the temperature rise due to ripple current. Therefore, the values of the electrical characteristics (εr = 3.1, tan δ = 0.005) of the film capacitor using the PEI film at 200 ° C. are given to the analysis model, and under normal use conditions (14 kHz, effective current 80 A). A temperature rise due to the ripple current was simulated, and the heat resistance condition (maximum temperature rise ΔT) of the capacitor according to Example 4 was obtained.

  In this simulation, the shape of the film capacitor in the capacitor of Example 4 and the arrangement form of the film capacitor with respect to the copper bar were the same as the capacitor of Reference Example 1. This is because the capacitor of Reference Example 1 is required to have the strictest heat resistance conditions. The PEI film has a dielectric breakdown voltage of 0.3 kV / μm when the thickness is 5 μm. When the rated voltage is 400 V and the surge voltage is allowed to 300 V, the re-thin film becomes 2.3 μm.

  As a result of analysis, the maximum temperature rise (ΔT) of the capacitor of Example 4 was 10.6 ° C. When the capacitor of Example 4 is used under a temperature condition of 200 ° C., the maximum heat resistance required for the PEI film is 210.6 ° C. Usually, the scale of the continuous use temperature of a capacitor is determined on the basis of Tg (glass transition temperature), and is (Tg-30) ° C. Since the TEI of the PEI film was 241 ° C. or higher, it was confirmed that the capacitor of Example 4 had heat resistance that could withstand continuous use as a capacitor corresponding to a SiC inverter.

(2) Examination of affinity between PEI film and vapor deposition metal The affinity between the PEI film and vapor deposition metal was examined using aluminum as the vapor deposition metal. Aluminum was deposited on the PEI film by ion plating and vacuum deposition.

  In any of the vapor deposition methods, aluminum can be easily vapor-deposited on the PEI film, and the vapor-deposited metal does not peel off even under high-temperature and long-term storage conditions (200 ° C., 1000 h), and no appearance abnormality was observed. From this, it was confirmed that the bondability between the PEI film and the deposited metal was good.

(3) Electrical characteristics thickness 19μm of the PEI film under high temperature conditions, using the PEI film of a single-sided surface area 0.052Cm ^2, to create a simple capacitor, subjected to electrical characteristic test of a simple capacitor created It was. Details of the simple capacitor are shown in Table 3.

  Further, FIG. 10 shows the result of measuring the change in the capacitance of the simple capacitor (14 kHz) in an environment of 200 ° C. From FIG. 10, it was confirmed that there was no change in the capacitance, and the film capacitor using the PEI film functioned as a capacitor for a long time even under use conditions in a high temperature environment. Moreover, it was confirmed that the film capacitor using the PEI film has sufficient electrical characteristics as a film capacitor corresponding to the SiC inverter by setting the dielectric loss tangent (tan δ) of the simple capacitor to 0.005 or less.

  As described above, according to the capacitor of the present invention, even when the shape of the capacitor is the current size, the heat dissipation of the capacitor can be improved.

  In addition, according to the capacitor of the present invention, the inductance of the entire capacitor can be reduced even if the shape of the film capacitor has a large inductance in order to increase the surface area. That is, both improvement in heat dissipation and reduction in inductance can be achieved.

  Moreover, the capacitor | condenser of this invention can endure use by high environmental temperature not only to suppress the maximum temperature rise of a film capacitor by using a PEI film for the dielectric film of a film capacitor. Film capacitors are used, for example, as smoothing capacitors in motor inverter circuits for hybrid vehicles and electric vehicles. In this application, there is a high demand for miniaturization and large current of capacitors. In the future, when switching elements such as SiC semiconductors that can be miniaturized at high speed will be used in inverters, it is conceivable that smoothing capacitors will be used in high-temperature environments such as 200 ° C., and films using the current polypropylene film It is assumed that a capacitor cannot be used. Therefore, by applying the capacitor of the present invention to such a field, it is possible to provide a capacitor that operates at a high ambient temperature and has a reduced surge voltage.

  Although the capacitor of the present invention has been described in detail only with respect to the specific examples described above, it is obvious to those skilled in the art that the capacitor of the present invention can be variously modified and modified within the scope of the technical idea. Of course, such variations and modifications are naturally within the scope of the technical idea of the capacitor of the present invention.

  For example, in the embodiment, a film capacitor using a polypropylene film is described as an example. However, the film capacitor is not limited to the embodiment, and a known film capacitor may be used as appropriate.

  The dielectric film used for the film capacitor may be appropriately selected and used according to the operating environment temperature of the capacitor. For example, when used at a low temperature (about 100 ° C.), a polypropylene film may be used, and when used at a high temperature (about 200 ° C.), a PEI film may be used. Examples of other dielectric film materials include polyethylene terephthalate (Tg = 80 ° C.), polyimide, polyphenylene sulfide (Tg = 260 ° C.), polyethylene naphthalate (Tg = 113 ° C.), polyether ether ketone (Tg = 166). ° C).

  Further, the number of film capacitors provided in the capacitor is not limited to the example, and the necessary number of film capacitors is used depending on the capacitance required for the capacitor and the capacitance of the film capacitor.

  In addition, when an insulating sheet is interposed between the film capacitors arranged in series (that is, between adjacent metallicon parts), a short circuit between the metallicon parts is prevented, so that the distance between the metallicon parts can be shortened. As a result, the inductance of the entire capacitor can be further reduced.

  The unit capacitor provided in the capacitor of the present invention is not limited to a film capacitor. For example, when a multilayer capacitor in which extraction electrodes are respectively formed on a pair of opposed surfaces is used as a unit capacitor. Applicable. In order to increase the surface area of the unit capacitor by increasing the surface area of the unit capacitor by increasing the surface area of the unit capacitor by making the unit capacitor arrangement form the same as the film capacitor arrangement form of the embodiment. Even if the shape of the unit capacitor is large, the inductance of the entire capacitor can be reduced. That is, both improvement in heat dissipation and reduction in inductance can be achieved.

1, 1a, 1b ... film capacitor 2 ... dielectric film 3 ... metal layer (metal vapor deposition electrode)
4 ... Metal vapor deposition film 5 ... Winding core 6, 6a, 6b ... Metallicon part (extraction electrode)
6c ... Connection 7 ... Lead wires 8, 14, 15, 16, 17 ... Capacitors 9, 9a, 9b, 10 ... Copper bars 11, 11a, 11b ... Film capacitor group 12 ... Insulating sheet 13 ... Case

Claims (7)

A plurality of films in which a pair of metal vapor deposition films formed with metal vapor deposition electrodes are overlapped and wound on one side of a dielectric film, and flat ellipsoidal extraction electrodes are provided on both end faces perpendicular to the winding axis of the winding body A capacitor,
A plate-like first electrode terminal to which one extraction electrode of the film capacitor is connected;
A plate-like second electrode terminal to which the other extraction electrode of the film capacitor is connected;
A capacitor having
Forming the major axis of the extraction electrode of the film capacitor equal to the length of one side of the plate surface of the first electrode terminal;
The film capacitor is arranged so that the minor axis of the extraction electrode surface is perpendicular to the plate surface of the first electrode terminal, and the extraction electrode surface connected to the positive electrode and the extraction electrode surface connected to the negative electrode are A film capacitor group is formed by arranging film capacitors adjacent to each other so as to face each other at a distance. The capacitor according to claim 1, wherein the film capacitor group is stacked in a minor axis direction of an extraction electrode of the film capacitor constituting the film capacitor group. The sheet-like insulator is provided between the extraction electrode of the film capacitor and the extraction electrode of another film capacitor that is spaced apart from the extraction electrode. Capacitor. The plate surface of the first electrode terminal and the plate surface of the second electrode terminal are overlapped via an insulating sheet,
4. The capacitor according to claim 1, wherein film capacitor groups are stacked on the plate surface of the first electrode terminal. 5. The capacitor according to any one of claims 1 to 4, wherein the dielectric film contains polyetherimide. The capacitor according to claim 5, wherein the dielectric film is a polyetherimide film having a dielectric loss tangent at 200 ° C. of 0.005 or less. A plurality of unit capacitors having extraction electrodes formed on a pair of opposing surfaces;
A plate-like first electrode terminal to which one extraction electrode of the unit capacitor is connected;
A plate-like second electrode terminal to which the other extraction electrode of the unit capacitor is connected;
A capacitor having
Forming the long side of the extraction electrode of the unit capacitor equal to the length of one side of the plate surface of the first electrode terminal;
The unit capacitor is arranged so that the extraction electrode surface is perpendicular to the plate surface of the first electrode terminal, and the extraction electrode surface connected to the positive electrode and the extraction electrode surface connected to the negative electrode are separated from each other. A unit capacitor group is configured by arranging adjacent unit capacitors so as to face each other.

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