(Extracted from wipo)
Title of the invention: Power converter
Technical field
[0001]
　The present invention relates to a power conversion device in which a power semiconductor element is sealed in a housing with a resin member.
Background art
[0002]
　In recent years, vehicles using a motor as a driving force source, such as a hybrid vehicle and an electric vehicle, have been actively developed in the automobile industry. An inverter device that drives a motor supplies high-voltage driving power to the motor using a battery as a power supply. In addition, a resin-sealed power semiconductor device is used for the inverter device, and in the field of power electronics, the power conversion device is increasingly important as a key device.
[0003]
　Here, the power semiconductor element used for the inverter device is sealed with a resin together with other components. In such a power converter, when electronic components such as a power semiconductor element and a smoothing capacitor constituting a snubber circuit are short-circuited while power is supplied from a battery, an excessive short-circuit current flows. For example, when the upper and lower arms of the inverter are short-circuited due to a malfunction of the gate drive circuit in the inverter control circuit, an overcurrent flows through the power semiconductor element and a short-circuit fault occurs.
[0004]
　If a relay that connects the battery and the motor drive circuit is connected or kept connected in the short-circuit state, the power converter emits smoke and burns due to a large current. Also, it is conceivable that a battery connected to the inverter device for driving a motor may be damaged due to the flow of an overcurrent exceeding the rating. In order to avoid such a situation, a sensor for detecting an overcurrent is usually used to control the switching of the power semiconductor element at high speed to interrupt the current when the overcurrent flows. However, even when a short-circuit fault occurs in the power semiconductor element, it is desired to more reliably prevent the above-described failure mode such as smoking.
[0005]
　Specifically, for example, if an overcurrent cutoff fuse is inserted between the power semiconductor device and the battery, an overcurrent flowing between the motor driving inverter device and the battery can be prevented.
[0006]
　However, chip type overcurrent cutoff fuses are expensive. Therefore, there is a need for an overcurrent interrupting unit that is inexpensive and can reliably shut off an overcurrent that can flow to a battery when a short-circuit fault occurs in a power semiconductor element.
[0007]
　For example, in Patent Literature 1 below, a cutout is provided in an electrode lead frame which is sealed with a resin and protrudes from a packaged semiconductor element module to form a fuse portion.
Prior art documents
Patent literature
[0008]
Patent Document 1: JP-A-2003-68967
Summary of the Invention
Problems to be solved by the invention
[0009]
　However, in the technique of Patent Document 1, the fuse portion provided in the electrode lead frame is exposed to the outside air. Therefore, when the fuse section is blown by an overcurrent, smoke may flow out of the apparatus, and sparks may scatter around the apparatus, and the apparatus may be burned out by a combustion reaction using outside air. Further, the blown fuse member may be scattered around and short-circuited to the surrounding members. In addition, since the cross-sectional area of the fuse portion is uniform, it is considered that the entire fuse portion generates heat and blows. In addition, since the heat generated by the fuse portion is easily transmitted to the electrode lead frames upstream and downstream of the fuse portion, the time required to melt the fuse portion becomes longer, and the transmitted heat may damage the power semiconductor element.
[0010]
　Therefore, there is a demand for a power conversion device that can suppress smoke, burnout, and short circuit even when the fuse is blown due to an overcurrent, and that makes it difficult for heat generated by the fuse to be transmitted to the power semiconductor element.
Means for solving the problem
[0011]
　A power converter according to the present invention includes a power semiconductor element, an electrode wiring member connected to a main electrode of the power semiconductor element, a housing, and a fuse formed on the electrode wiring member and serving as a fuse. A fuse resin member that is a resin member that covers the fuse portion, and a resin member that seals the power semiconductor element, the electrode wiring member, the fuse portion, and the fuse resin member in the housing. A resin member, and the fuse portion is a first stage portion on the upstream side having a smaller cross-sectional area than a portion of the electrode wiring member on the upstream side of the fuse portion along the direction of current flow; A second-stage portion having a smaller cross-sectional area than the first-stage portion on the upstream side; and a second-stage portion having a larger cross-sectional area than the second-stage portion, and a portion of the electrode wiring member downstream of the fuse portion. Sever Are those constituted by the first stage portion of the product is small downstream.
The invention's effect
[0012]
　According to the power conversion device of the present invention, since the fuse portion is formed in the electrode wiring member, an expensive chip-type fuse is not provided, and the cost of the fuse portion can be reduced. Since the sealing resin member covers the fuse portion and the fuse resin member, the blown fuse portion member can be prevented from scattering to the outside. In addition, since the fuse portion and the fuse resin member can be cut off from the outside air, it is possible to suppress the progress of the combustion reaction due to the arc discharge generated at the time of fusing, and to suppress the smoke generated at the time of fusing from leaking to the outside. it can. Since the fuse portion is covered with the fuse resin member, it is possible to suppress the member of the blown fuse portion from contacting the sealing resin member, and to prevent the sealing resin member from being damaged. Further, since a fuse resin member dedicated to the fuse portion is provided, a resin member made of a material suitable for fusing the fuse portion can be selected. Therefore, even if the fuse is blown due to the overcurrent, it is possible to suppress smoke, burnout, and short circuit.
[0013]
　Also, by reducing the cross-sectional area of the fuse portion in two stages, the current density and the thermal resistance increase in the order of the first stage portion and the second stage portion on the upstream side and the downstream side. Therefore, it is possible to maximize the temperature rise of the second stage portion and to perform the fusing. Since the heat generated in the second stage portion is less likely to be transmitted to the upstream and downstream portions than the fuse portion due to the thermal resistance of the first stage portion on the upstream side and the downstream side, the temperature rising speed of the second stage portion is increased. In addition, it is possible to shorten the time until the fusing and to reduce the heat transfer to the power semiconductor element.
BRIEF DESCRIPTION OF THE FIGURES
[0014]
FIG. 1 is a plan view of a power converter according to Embodiment 1 of the present invention.
FIG. 2 is a cross-sectional view of the power conversion device taken along a line AA in FIG. 1 according to Embodiment 1 of the present invention.
3 is a cross-sectional view of the power conversion device taken along a line BB in FIG. 1 according to Embodiment 1 of the present invention.
FIG. 4 is a plan view of a fuse section according to Embodiment 1 of the present invention.
FIG. 5 is a schematic diagram for explaining a current density of a fuse section according to Embodiment 1 of the present invention.
FIG. 6 is a diagram illustrating a temperature distribution of a fuse section according to Embodiment 1 of the present invention.
FIG. 7 is a diagram illustrating a temperature distribution of a fuse section according to a comparative example of the present invention.
FIG. 8 is a schematic diagram illustrating variations in the shape of the fuse section according to Embodiment 1 of the present invention.
FIG. 9 is a cross-sectional view of the power conversion device taken along a line AA in FIG. 1 according to Embodiment 2 of the present invention.
FIG. 10 is a perspective view of an electrode wiring member according to Embodiment 2 of the present invention.
FIG. 11 is a cross-sectional view of the power conversion device taken along a line AA in FIG. 1 according to Embodiment 3 of the present invention.
FIG. 12 is a cross-sectional view of the power conversion device taken along a line AA in FIG. 1 according to Embodiment 4 of the present invention.
FIG. 13 is a cross-sectional view of the power conversion device taken along a line AA in FIG. 1 according to Embodiment 5 of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0015]
Embodiment 1 FIG.
　The power conversion device 1 according to Embodiment 1 will be described with reference to the drawings. FIG. 1 is a plan view of the power conversion device 1 as viewed from the opening side of the housing 30. In order to explain the arrangement of each component, the sealing resin member 25 is made transparent and is not shown. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line BB in FIG. FIG. 4 is a plan view of the fuse section 16 as viewed from the front. Each drawing is a schematic diagram, and the dimensions of each member do not completely match between the drawings.
[0016]
　The power converter 1 includes a power semiconductor element 14, an electrode wiring member 13 connected to a main electrode of the power semiconductor element 14, a housing 30, and components such as the power semiconductor element 14 in the housing 30. And a sealing resin member 25 which is a resin member to be sealed.
[0017]
The
　case 30 is formed in a bottomed cylindrical shape, and has a role of a frame for casting the sealing resin member 25. In the following, the terms “inside”, “inside”, “outside”, and “outside” simply mean the inside or outside of the housing 30. The “vertical direction” refers to the direction in which the cylindrical portion of the housing 30 extends, and the “horizontal direction” refers to the direction in which the bottom of the housing 30 extends.
[0018]
　The bottom of the housing 30 is constituted by the metal heat sink 12. The heat sink 12 has a role of radiating heat generated in the power semiconductor element 14 to the outside. For the heat sink 12, for example, a material having a thermal conductivity of 20 W / (m • K) or more, such as aluminum or an aluminum alloy, is used. The heat sink 12 is formed, for example, in a rectangular flat plate shape. Note that the heat sink 12 may have a shape other than a rectangle. An inner surface portion of the heat sink 12 facing the member on the side of the power semiconductor element 14 is provided with an inwardly protruding plate-shaped element opposing projection 12a, and the inner surface of the element opposing projection 12a is Abuts the member on the 14 side. As shown in FIG. 2, a plurality of flat fins 19 arranged at intervals from each other are provided on the outer surface of the heat sink 12. The fins 19 are in contact with the outside air, and the heat sink 12 radiates heat from these fins 19 to the outside air. Note that a water-cooled type may be used.
[0019]
　The cylindrical portion of the housing 30 is constituted by the insulating case 11. The insulating case 11 is formed using any resin material having high insulating properties and thermoplasticity, for example, a resin material such as polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK). You.
[0020]
In the
　present embodiment, the power semiconductor element 14 and the electrode lead frame 13 as the electrode wiring member 13 are sealed with the element molding resin 20 which is a resin member. , And a packaged semiconductor element module 29. The control lead frame 21 connected to the control terminal of the power semiconductor element 14 is also sealed with the element molding resin 20. The electrode lead frame 13 and the control lead frame 21 project outward from the element mold resin 20. As the element mold resin 20, a hard resin having a Young's modulus of several GPa or more is preferably used in order to protect internal elements and wiring, and for example, an epoxy resin is used.
[0021]
　As the power semiconductor element 14, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used. The power semiconductor element 14 may be another type of switching element such as a power IGBT (Insulated Gate Bipolar Transistor) in which diodes are connected in anti-parallel. The power semiconductor element 14 is used for, for example, an inverter circuit and a converter circuit for driving a device such as a motor for driving a vehicle, and controls a rated current of several amps to several hundred amps. As a material of the power semiconductor element 14, silicon (Si), silicon carbide (SiC), gallium nitride (GaN), or the like may be used.
[0022]
　The power semiconductor element 14 is formed in a rectangular flat chip shape, a drain terminal as a main electrode is provided on a surface on the heat sink 12 side, and a main electrode is formed on a surface of the housing 30 opposite to the heat sink 12. Are provided. Further, a gate terminal as a control terminal is provided on a surface of the housing 30 opposite to the heat sink 12. Note that a sensor terminal or the like for detecting a current flowing between the main electrodes or a temperature of the chip may be provided as the control terminal.
[0023]
　The drain terminal is connected to the positive electrode lead frame 13a, and the source terminal is connected to the negative electrode lead frame 13b via an electrode wiring member 15a. Since a large current flows through the electrode wiring member 15a, the electrode wiring member 15a is formed by, for example, processing a plate material of gold, silver, copper, or aluminum, or by wire bonding or ribbon bonding. The gate terminal and the sensor terminal are connected to the control lead frame 21 via the control wiring member 15b. The control wiring member 15b can be formed by, for example, a wire bond of gold, copper, aluminum, or the like, or a ribbon bond of aluminum.
[0024]
　The electrode lead frames 13a and 13b on the positive and negative electrode sides are formed in a plate shape (in this example, a rectangular flat plate shape). The electrode connection portions of the electrode lead frames 13a and 13b connected to the main electrodes of the power semiconductor element 14 are arranged closer to the heat sink 12 than the power semiconductor element 14 is. The surface of the electrode connection portion of the electrode lead frame 13a on the positive electrode side opposite to the heat sink 12 is joined to the drain terminal on the heat sink 12 side of the power semiconductor element 14 by a conductive joining material 17. The surface of the electrode connection portion of the electrode lead frame 13b on the negative electrode side opposite to the heat sink 12 is joined to one end of an L-shaped electrode wiring member 15a by a conductive joining material 17. The source terminal of the power semiconductor element 14 on the side opposite to the heat sink 12 is joined to the other end of the electrode wiring member 15 a by a conductive joining material 17. The conductive bonding material 17 is made of a material having good conductivity and high thermal conductivity, such as solder, silver paste, or a conductive adhesive.
[0025]
　The surfaces of the electrode lead frames 13a and 13b on the heat sink 12 side of the electrode connection portions are not covered with the element molding resin 20 and are exposed outside the semiconductor element module 29. The exposed portions of the electrode lead frames 13a and 13b are in contact with the inner surface of the element facing projecting portion 12a of the heat sink 12 via an insulating member 18 formed in a sheet shape. Heat generated by the power semiconductor element 14 is transmitted to the heat sink 12 via the electrode connection portions of the electrode lead frames 13a and 13b and the insulating member 18. The insulating member 18 is made of a material having high thermal conductivity and high electrical insulation. Therefore, the insulating member 18 has, for example, a thermal conductivity of 1 W / (m • K) to several tens W / (m • K) and has insulating properties such as a silicon resin, an epoxy resin, and a urethane resin. It is made of an adhesive, grease, or an insulating sheet made of a resin material. Further, the insulating member 18 can be configured by combining another material having a low thermal resistance such as a ceramic substrate or a metal substrate and having an insulating property with a resin material.
[0026]
　Further, in order to regulate the thickness of the insulating member 18, a projection 20 a is provided on the heat sink 12 side of the element molding resin 20. By pressing the protrusion 20a of the element mold resin 20 against the heat sink 12, the thickness of the insulating member 18 can be regulated by the height of the protrusion 20a, and the insulating property and the heat transfer property of the insulating member 18 can be controlled. it can. For example, in a low-voltage automobile using a 12V battery, the creepage distance required to secure a predetermined dielectric strength is about 10 μm. Therefore, in the case of a low-withstand-voltage vehicle, the thickness required for insulation can be reduced, so that the protrusion 20a of the element mold resin 20 can be shortened, and the power converter 1 can be made thinner. If the insulating member 18 is made of a material having rigidity and a change in thickness due to pressing is small, the thickness of the insulating member 18 can be controlled, and therefore the projection 20a of the element mold resin 20 may not be provided.
[0027]
　After the lead frame 13a for the positive electrode protrudes from the element mold resin 20, the lead frame 13a extends laterally along the inner surface of the heat sink 12 while being spaced from the inner surface of the heat sink 12, and then bends. It extends in the vertical direction on the side away from 12 (opening side of the housing 30). The portion extending in the horizontal direction at a distance from the inner surface of the heat sink 12 is referred to as a positive electrode side lead frame horizontal extension 13a1, and the portion extending in the vertical direction away from the heat sink 12 This is referred to as a positive electrode side lead frame vertical extension 13a2. A fuse portion 16 described later is formed on the lead frame vertical extension 13a2 on the positive electrode side.
[0028]
　The external connection terminal 10 a on the positive electrode side is inserted and outsert into the insulating case 11. The external connection terminal 10a on the positive electrode side has an external connection vertical extension 10a1 extending in the vertical direction and an external connection extension extending laterally from the end of the external connection vertical extension 10a1 on the heat sink 12 side. And a connection lateral extension 10a2. The open end of the external connection vertical extension 10a1 on the positive electrode side is joined to the open end of the positive frame lead frame vertical extension 13a2 by welding or soldering. There is a gap between the external connection vertical extension 10a1 on the positive electrode side and the lead frame vertical extension 13a2 on the positive electrode side, except for the joining portion at the tip, and there is no conduction. The part protruding outside from the housing 30 is connected to another device such as a positive electrode of a DC power supply.
[0029]
　The negative electrode-side electrode lead frame 13b also protrudes from the element mold resin 20, is spaced apart from the inner surface of the heat sink 12, and extends along the inner surface of the heat sink 12 so as to extend along the inner surface of the heat sink 12. And a lead frame vertical extension 13b2 on the negative electrode side extending to a side away from the heat sink 12.
[0030]
　The external connection terminal 10 b on the negative electrode side is inserted and outsert into the insulating case 11. The external connection terminal 10b on the negative electrode side has an external connection vertical extension 10b1 extending in the vertical direction and an external connection extension extending laterally from the end of the external connection vertical extension 10b1 on the heat sink 12 side. And a connection laterally extending portion 10b2. The opening-side tip of the external connection vertical extension 10b1 is joined to the opening-side tip of the negative electrode lead frame vertical extension 13b2 by welding or soldering. A gap is provided between the external connection vertical extension 10b1 on the negative electrode side and the lead frame vertical extension 13b2 on the negative electrode side, except for the joining portion at the tip, and there is no conduction. The portion protruding from the housing 30 to the outside is connected to another device such as a negative electrode of a DC power supply.
[0031]
　For the electrode lead frames 13a and 13b and the external connection terminals 10a and 10b, a metal such as copper or a copper alloy, aluminum, or an aluminum alloy having good conductivity and high thermal conductivity is used. Large current flows. The surfaces of the electrode lead frames 13a and 13b may be plated with a metal material such as Au, Ni, or Sn.
[0032]
　The control lead frame 21 protrudes from the sealing resin member 25 on the opening side of the housing 30 and is connected to a control device that controls on / off of the power semiconductor element 14.
[0033]

　A fuse section 16 functioning as a fuse is formed in the electrode wiring member 13 (in this example, the lead frame vertical extension 13a2 on the positive electrode side). As shown in FIG. 4, the fuse portion 16 is configured by a portion of the electrode wiring member 13 whose cross-sectional area is reduced in two stages from each of the upstream portion and the downstream portion in the current flow direction in the electrode wiring member 13. I have. Specifically, as shown in FIG. 4, a view of the fuse section 16 as viewed from the front, the fuse section 16 is located at a position closer to the electrode wiring member on the upstream side than the fuse section 16 along the current flow direction. The first-stage portion 16a1 on the upstream side also has a smaller cross-sectional area, the second-stage portion 16b having a smaller cross-sectional area than the first-stage portion 16a1 on the upstream side, and a larger cross-sectional area than the second-stage portion 16b. The first stage portion 16a2 on the downstream side has a smaller sectional area than the electrode wiring member 13 on the downstream side of the fuse portion 16.
[0034]
　For example, the ratio of the cross-sectional area of each part is as follows. Cross-sectional area of upstream / downstream portion: cross-sectional area of first-stage portion on upstream / downstream side: cross-sectional area of second-stage portion = 7.5: 1.5: 1. That is, the order of the size of the cross-sectional area of each part is “cross-sectional area of the upstream / downstream portion> cross-sectional area of the first-stage portion on the upstream / downstream side> cross-sectional area of the second-stage portion”. Here, the value of the ratio of the cross-sectional areas is an example, and the same effect can be obtained if the order of the cross-sectional areas is the same.
[0035]
　By thus reducing the cross-sectional area in two stages, as shown in FIG. 5, the current density increases as the cross-sectional area decreases, and the current density in the second stage portion 16b becomes the largest. As shown in equation (1), the thermal resistance increases as the cross-sectional area decreases. As a result, the heat generation density increases stepwise, the heat radiation property deteriorates stepwise, the temperature rise of the second stage portion 16b becomes the largest, and the second stage portion 16b is blown.
　　Thermal resistance = length ÷ (thermal conductivity x cross-sectional area) ... (1)
[0036]
　FIG. 6 shows a temperature distribution of the fuse section 16 when a current is applied. FIG. 6 shows a case of the present embodiment in which the sectional area is reduced in two stages. FIG. 7 shows a comparative example in which the cross-sectional area is reduced in one step, in which the first-stage portion is provided, but the second-stage portion is not provided. The fuse portion 16 is formed by cutting out a flat plate-shaped electrode lead frame from both sides by pressing. The width of the second-stage portion 16b is set to the limit of mass production by pressing. Has been equivalent to.
[0037]
　In FIG. 6 according to the present embodiment, the temperature is highest at second stage portion 16b, and the temperature gradually decreases in first stage portions 16a1 and 16a2 as the distance from second stage portion 16b increases. Further, the heat generation of the second stage portion 16b is less likely to be transmitted to the upstream and downstream portions than the fuse portion 16 by the first stage portions 16a1 and 16a2 having a large thermal resistance, and the temperature rising speed of the second stage portion 16b is increased. In addition, the time until fusing can be reduced. Therefore, when an overcurrent flows, the temperature of the second-stage portion 16b having the smallest sectional area rapidly rises in a short time. When the temperature rises to the melting point of the metal, the second stage portion 16b is torn. In addition, the first-stage portions 16a1 and 16a2 having a large thermal resistance prevent the heat generated in the second-stage portion 16b from being transmitted to the upstream and downstream portions of the fuse portion 16, so that the power semiconductor element 14 Damage to the resin stopper 25 and the like can be suppressed. In addition, by changing the width and length of the notch, the relationship between the current and the time until the fracture is adjusted is adjusted, and desired fusing characteristics can be obtained. In addition, the provision of the fuse portion 16 reduces the cross-sectional area of the electrode lead frame and lowers the rigidity, so that thermal stress due to a temperature change is relaxed and the reliability of the joint can be expected to be improved.
[0038]
　In FIG. 7 according to the comparative example, the temperature of the entire fuse portion 16 is uniformly increased. Therefore, when an overcurrent flows, the temperature of the fuse portion 16 rises as a whole, and the entire fuse portion 16 is blown, or a blown portion varies. Further, since the entire temperature rises, the time until fusing increases, and more heat is transferred to the upstream and downstream portions than the fuse portion 16. At the time of fusing, the temperature as a whole is higher than the temperature shown in FIG. 7, and the temperature of the upstream and downstream portions of the fuse 16 is also higher than that in FIG.
[0039]
　In the present embodiment, the length of the second stage portion 16b in the current flow direction is the length of the upstream first stage portion 16a1 in the current flow direction and the length of the downstream first stage portion 16a2. The length is shorter than the length in the current flow direction. According to this configuration, the fusing portion of the fuse portion 16 can be shortened, and the amount of the fusing member can be reduced. Since the first stage portions 16a1 and 16a2 are lengthened, the thermal resistance can be increased, the temperature rising speed of the second stage portion 16b can be increased, and the amount of heat transmitted to the upstream and downstream portions of the fuse portion 16 can be reduced. it can. For example, the length of the second stage portion 16b in the current flow direction is equal to or less than half (for example, one third) the length of the upstream and downstream first stage portions 16a1 and 16a2 in the current flow direction. ).
[0040]
　The fuse section 16 is made of gold, silver, copper, or aluminum having high electric conductivity. The fuse portion 16 may be made of the same material as the other portions of the electrode lead frame 13, or a different material may be used. Although not limited to this, the fuse portion 16 is formed by punching a flat plate made of copper or a copper alloy having a thickness of about 0.5 mm to 1.5 mm, similarly to other portions of the electrode lead frame 13. Can be formed.
[0041]
　The first stage portions 16a1 and 16a2 on the upstream side and the downstream side have the same sectional area at each position in the current flow direction. In the present embodiment, the first-stage portions 16a1 and 16a2 on the upstream side and the downstream side are formed in a rectangular parallelepiped shape having the same length and the same cross-sectional area. The first stage portions 16a1 and 16a2 on the upstream side and the downstream side may have different lengths and different cross-sectional areas. Further, the cross-sectional shape of the first-stage portions 16a1 and 16a2 on the upstream side and the downstream side may be an arbitrary shape such as a round shape and an elliptical shape other than the rectangular shape.
[0042]
　The second stage portion 16b is formed in a rectangular parallelepiped shape. The shape of the second-stage portion 16b may be any shape as long as the cross-sectional area is smaller than the first-stage portions 16a1 and 16a2 on the upstream and downstream sides. For example, as shown in FIG. 8, notches may be provided on one or both sides, or through holes may be provided on the inside to reduce the cross-sectional area. The shape of the notch or the through hole may be any shape such as a triangle, a pentagon, a trapezoid, a rhombus, a parallelogram, a circle, an ellipse, etc., in addition to a rectangle. The number of notches or through holes is not limited to one, and a plurality of notches or through holes may be provided. In addition, a plurality of notches or through holes may be staggered, staggered, or irregularly arranged at different positions in the length direction of the wiring. The plurality of through holes may be arranged in either the width direction or the length direction of the wiring.
[0043]
A fuse resin member 26
　which is a resin member covering the fuse portion 16 is provided. The fuse resin member 26 is disposed so as to cover at least one surface of the second-stage portion 16b which is a fusing portion. In the present embodiment, as shown in FIG. 2, the fuse resin member 26 is formed on one surface of the fuse portion 16 in the thickness direction (in this example, the surface on the opposite side to the external connection terminal 10a on the positive electrode side). It is configured to cover. As shown in FIG. 4, the fuse resin member 26 is arranged in an area larger than the area of the fuse part 16. Note that the fuse resin member 26 may be disposed so as to cover both surfaces in the width direction of the fuse portion 16.
[0044]
　Before filling the casing 30 with the sealing resin member 25, the fuse resin member 26 is disposed so as to cover the fuse portion 16. The fuse resin member 26 is formed of an adhesive, grease, or an insulating sheet having a high electrical insulation property and made of a resin material such as a silicon resin, an epoxy resin, or a urethane resin.
[0045]
　By covering the fuse portion 16 with the fuse resin member 26, it is possible to prevent the blown fuse member 16 from coming into contact with the sealing resin member 25 and to prevent the sealing resin member 25 from being damaged. Further, since the fuse resin member 26 dedicated to the fuse portion 16 is provided, it is possible to select a resin member of a material suitable for fusing the fuse portion 16.
[0046]
　In the present embodiment, a resin member having a lower Young's modulus than sealing resin member 25 is used as fuse resin member 26. For example, the Young's modulus of the fuse resin member 26 is on the order of several tens of MPa (megapascal) (for example, a value between 10 MPa and 30 MPa), and for example, a rubber material, silicone rubber, or silicone gel may be used. According to this configuration, when the fuse portion 16 is blown, a plurality of spherical lump-shaped splattered melt members are sunk into the soft fuse resin member 26 having a lower Young's modulus than the sealing resin member 25. Instead, it can be dispersed and held in the fuse resin member 26. Therefore, after the fusing, the current path can be prevented from being maintained by the melted member, and the current path can be rapidly cut. Further, it is possible to prevent the sealing resin member 25 having a high Young's modulus from being cracked by the melted member.
[0047]
　As the fuse resin member 26, it is preferable to use a silicon resin having an arc extinguishing action of an arc discharge generated when the fuse portion 16 is blown. According to this configuration, even after the fuse portion 16 is blown, the continuation of current supply due to arc discharge can be suppressed, and the current can be cut off immediately after the blow. Therefore, damage to the power semiconductor element 14, the sealing resin member 25, and the like can be suppressed.
[0048]
The
　sealing resin member 25 is a resin member that seals the power semiconductor element 14, the electrode wiring member 13, the fuse portion 16, and the fuse resin member 26 in the housing 30. In the present embodiment, the sealing resin member 25 is configured to seal the semiconductor element module 29 in the housing 30. The sealing resin member 25 also seals other components such as the insulating member 18 and the external connection terminals 10a and 10b in the housing 30. As the sealing resin member 25, for example, a resin material having high rigidity and high thermal conductivity is used. The sealing resin member 25 may be made of, for example, epoxy resin, silicone resin, urethane resin, PPS, PEEK, or ABS containing a thermally conductive filler. The sealing resin member 25 preferably has a Young's modulus of 1 MPa to 50 GPa and a thermal conductivity of 0.1 W / (m • K) to 20 W / (m • K). By sealing each component with the sealing resin member 25, vibration resistance and environmental resistance can be improved.
[0049]
　Since the fuse portion 16 and the fuse resin member 26 are covered with the sealing resin member 25, the blown-out member of the fuse portion 16 can be prevented from scattering outside. Since the fuse portion 16 and the fuse resin member 26 can be cut off from the outside air, it is possible to suppress the progress of the combustion reaction due to the arc discharge generated at the time of fusing, and to suppress the smoke generated at the time of fusing from leaking to the outside. it can.
[0050]
Embodiment 2 FIG.
　Next, the power conversion device 1 according to Embodiment 2 will be described. The description of the same components as those in the first embodiment is omitted. The basic configuration of the power converter 1 according to the present embodiment is the same as that of the first embodiment, but the configuration of the electrode wiring member 13 is partially different. FIG. 9 is a cross-sectional view of the power conversion device 1 according to the present embodiment, taken along a line AA in FIG. FIG. 10 is a perspective view of the electrode lead frame 13a on the positive electrode side.
[0051]
　As in the first embodiment, a fuse portion 16 functioning as a fuse is formed in the electrode wiring member 13 (the electrode lead frame 13a on the positive electrode side). Unlike the first embodiment, the electrode wiring member 13 (the electrode lead frame 13a on the positive electrode side) has a smaller cross-sectional area on the part closer to the power semiconductor element 14 than the fuse part 16 than on the upstream and downstream parts. It has a small cross section 31. Note that the cross-sectional area of the small cross-sectional area 31 is larger than the cross-sectional area of the second-stage portion 16b of the fuse section 16.
[0052]
　The small cross-sectional area 31 is provided on the lead frame laterally extending portion 13a1 on the positive electrode side that protrudes laterally from the element mold resin 20. The small cross-sectional area 31 is formed by providing two cylindrical through holes in the width direction that penetrate the electrode lead frame 13a in the thickness direction. The small cross-sectional area 31 may be located in the element mold resin 20 instead of the portion protruding from the element mold resin 20. Thereby, since the element mold resin 20 enters the small cross-sectional area portion 31, separation can be prevented by the anchor effect.
[0053]
　By providing the fuse section 16, the fuse section 16 generates heat even when a normal current flows. Therefore, it is necessary to limit the output of the power converter 1 so that the heat transmitted to the power semiconductor element 14 does not become too large, which is a design constraint. The provision of the small cross-sectional area 31 increases the thermal resistance, so that the heat generated by the fuse section 16 is less likely to be transmitted to the power semiconductor element 14, so that the output limitation of the power converter 1 during normal operation is eased. be able to.
[0054]
　The small cross-sectional area 31 may have any shape as long as the cross-sectional area is smaller than the upstream and downstream portions. For example, similarly to the second stage portion 16b, a cutout may be provided on one or both sides, or a through hole may be provided on the inside to reduce the cross-sectional area. The shape of the notch or the through hole may be any shape such as a triangle, a pentagon, a trapezoid, a rhombus, a parallelogram, a circle, an ellipse, etc., in addition to a rectangle. The number of notches or through holes is not limited to one, and a plurality of notches or through holes may be provided. In addition, a plurality of notches or through holes may be staggered, staggered, or irregularly arranged at different positions in the length direction of the wiring. The plurality of through holes may be arranged in either the width direction or the length direction of the wiring.
[0055]
Embodiment 3 FIG.
　Next, the power conversion device 1 according to Embodiment 3 will be described. The description of the same components as those in the first embodiment is omitted. The basic configuration of the power conversion device 1 according to the present embodiment is the same as that of the first embodiment, but the configurations of the fuse resin member 26 and the external connection terminal 10a on the positive electrode side are partially different. FIG. 11 is a cross-sectional view of the power conversion device 1 according to the present embodiment, taken along a line AA in FIG.
[0056]
　As in the first embodiment, the fuse resin member 26 is configured to cover one surface in the thickness direction of the fuse portion 16 (in this example, the surface on the opposite side to the external connection terminal 10a on the positive electrode side). Have been. However, unlike the first embodiment, the portion of the external connection terminal 10a (external connection vertical extension 10a1) on the positive electrode side facing the fuse portion 16 is recessed on the side away from the fuse portion 16, and The distance between the positive connection 16 and the external connection terminal 10a on the positive electrode side is increased. A fuse resin member 26 is also arranged at this interval, and the fuse resin member 26 is configured to cover the other surface of the fuse portion 16 (in this example, the surface of the positive electrode side on the side of the external connection terminal 10a). Have been. Further, the fuse resin members 26 are also arranged on both sides in the width direction of the fuse portion 16, and are arranged so as to cover the entire periphery of the fuse portion 16. By disposing a fuse resin member 26 having a lower thermal conductivity than the positive side external connection terminal 10a between the fuse part 16 and the positive side external connection terminal 10a, the heat radiation of the fuse part 16 is deteriorated, and Characteristics can be improved. Further, it is possible to prevent the fusing member of the fuse portion 16 from contacting the external connection terminal 10a on the positive electrode side and maintaining the current supply path.
[0057]
Embodiment 4 FIG.
　Next, a power conversion device 1 according to Embodiment 4 will be described. The description of the same components as those in the first embodiment is omitted. The basic configuration of the power conversion device 1 according to the present embodiment is the same as that of the first embodiment, but the configurations of the fuse portion 16 and the fuse resin member 26 are partially different. FIG. 12 is a cross-sectional view of the power conversion device 1 according to the present embodiment, taken along a line AA in FIG.
[0058]
　As in the first embodiment, the fuse resin member 26 is configured to cover one surface in the thickness direction of the fuse portion 16 (in this example, the surface on the opposite side to the external connection terminal 10a on the positive electrode side). Have been. However, different from the first embodiment, the other surface of the fuse portion 16 (the surface on the side of the external connection terminal 10a on the positive electrode side) is depressed on the side away from the external connection terminal 10a on the positive electrode side. The thickness (plate thickness) of the fuse portion 16 is smaller than the portion on the upstream side and the downstream side of the fuse portion 16 by the amount of the depression. Further, the distance between the fuse portion 16 and the external connection terminal 10a on the positive electrode side is increased by the amount of the depression. A fuse resin member 26 is also arranged at this interval, and the fuse resin member 26 is configured to cover the other surface of the fuse portion 16 (in this example, the surface of the positive electrode side on the side of the external connection terminal 10a). Have been. Further, the fuse resin members 26 are also arranged on both sides in the width direction of the fuse portion 16, and are arranged so as to cover the entire periphery of the fuse portion 16.
[0059]
　By disposing a fuse resin member 26 having a lower thermal conductivity than the positive side external connection terminal 10a between the fuse part 16 and the positive side external connection terminal 10a, the heat radiation of the fuse part 16 is deteriorated, and Characteristics can be improved. Further, it is possible to prevent the fusing member of the fuse portion 16 from contacting the external connection terminal 10a on the positive electrode side and maintaining the current supply path. By covering the entire circumference, the peeling of the fuse resin member 26 can be prevented by the anchor effect, and the fusing performance can be stabilized.
[0060]
　Further, by reducing the thickness of the fuse portion 16, the sectional area of the fuse portion 16 can be reduced, the time until fusing can be shortened, and the heat transfer to the upstream and downstream portions of the fuse portion 16 can be reduced. Thereby, the output limitation of the power converter 1 during normal operation can be eased.
[0061]
　Examples of the method of reducing the thickness of the fuse portion 16 include a method of using a different member having a small thickness for the fuse portion 16, a method of performing press working, and a method of cutting, but are not limited thereto.
[0062]
Embodiment 5 FIG.
　Next, a power conversion device 1 according to Embodiment 5 will be described. The description of the same components as those in the first embodiment is omitted. The basic configuration of the power converter 1 according to the present embodiment is the same as that of the first embodiment, but the configurations of the fuse portion 16 and the fuse resin member 26 are partially different. FIG. 13 is a cross-sectional view of the power conversion device 1 according to the present embodiment, taken along a line AA in FIG.
[0063]
　As in the first embodiment, the fuse resin member 26 is configured to cover one surface in the thickness direction of the fuse portion 16 (in this example, the surface on the opposite side to the external connection terminal 10a on the positive electrode side). Have been. However, unlike in the first embodiment, the fuse portion 16 is located on one side in the thickness direction of the electrode wiring member 13 on the upstream side and the downstream side of the fuse portion 16 (in this example, the external connection on the positive side). (In a direction away from the terminal 10a). The fuse portion 16 is formed at a portion of the electrode wiring member 13 which is bent and protruded in an angular C shape in a direction away from the external connection terminal 10a on the positive electrode side. The thickness (plate thickness) of the protruding fuse portion 16 is smaller than the portion on the upstream side and the downstream side of the fuse portion 16. The distance between the fuse portion 16 and the external connection terminal 10a on the positive electrode side is increased by the amount of the protrusion. A fuse resin member 26 is also arranged at this interval, and the fuse resin member 26 is configured to cover the other surface of the fuse portion 16 (in this example, the surface of the positive electrode side on the side of the external connection terminal 10a). Have been. Further, the fuse resin members 26 are also arranged on both sides in the width direction of the fuse portion 16, and are arranged so as to cover the entire periphery of the fuse portion 16.
[0064]
　By disposing a fuse resin member 26 having a lower thermal conductivity than the positive side external connection terminal 10a between the fuse part 16 and the positive side external connection terminal 10a, the heat radiation of the fuse part 16 is deteriorated, and Characteristics can be improved. Further, it is possible to prevent the fusing member of the fuse portion 16 from contacting the external connection terminal 10a on the positive electrode side and maintaining the current supply path. By adjusting the amount of protrusion of the fuse portion 16, the thickness of the fuse resin member 26 can be adjusted, and the effect can be optimized. By covering the entire periphery of the bent portion, the fuse resin member 26 can be prevented from peeling off by the anchor effect, and the fusing performance can be stabilized. Further, by providing the bent portion, the thermal stress due to the temperature change is relaxed, and the reliability of the joint can be improved.
[0065]
　Further, by reducing the thickness of the fuse portion 16, the sectional area of the fuse portion 16 can be reduced, the time until fusing can be shortened, and the heat transfer to the upstream and downstream portions of the fuse portion 16 can be reduced. Thereby, the output limitation of the power converter 1 during normal operation can be eased.
[0066]
　As a method of projecting the fuse portion 16 into a square C shape and reducing the thickness, for example, there are a method of using a thin member having a small thickness for the fuse portion 16, a method of performing press working, and a method of cutting. However, the present invention is not limited to these.
[0067]
[Other Embodiments]
　Finally, other embodiments of the present invention will be described. Note that the configuration of each embodiment described below is not limited to being applied independently, and can be applied in combination with the configuration of another embodiment as long as no contradiction occurs.
[0068]
(1) In each of the above embodiments, the semiconductor element module 29 in which the power semiconductor element 14 and the electrode lead frame 13 as the electrode wiring member 13 are sealed with the element molding resin 20 which is a resin member. The above description has been made by way of example. However, embodiments of the present invention are not limited to this. That is, the power semiconductor element 14 and the electrode wiring member 13 may not be sealed with the element molding resin 20 and may not be packaged. That is, the power semiconductor element 14, the electrode wiring member 13, and the like that are not sealed with the element molding resin 20 may be sealed in the housing 30 by the sealing resin member 25. In this case, the electrode wiring member 13 may be a bus bar or the like, and the fuse portion 16 may be formed in a portion of the electrode wiring member on the positive electrode side or the negative electrode side sealed with the sealing resin member 25.
[0069]
(2) In each of the above embodiments, the case where the fuse portion 16 is formed on the positive electrode lead frame 13a (lead frame vertical extension portion 13a2) has been described as an example. However, embodiments of the present invention are not limited to this. That is, the fuse portion 16 may be formed at any position as long as it is connected to the main electrode of the power semiconductor element 14 and is the portion of the electrode wiring member 13 sealed with the sealing resin member 25. For example, the fuse portion 16 may be formed on the negative electrode side electrode lead frame 13b, the positive electrode side lead frame laterally extending portion 13a1, or the positive electrode side or negative electrode side external connection terminals 10a and 10b.
[0070]
(3) In each of the above embodiments, the case where the power converter 1 is provided with one power semiconductor element 14 (switching element) has been described as an example. However, embodiments of the present invention are not limited to this. That is, the power converter 1 may be provided with a plurality of power semiconductor elements. For example, two switching elements may be connected in series between the electrode wiring member on the positive electrode side and the electrode wiring member on the negative electrode side, and the fuse portion 16 may be formed on the electrode wiring member on the positive electrode side or the negative electrode side. Further, a series circuit of two switching elements is formed as a bridge circuit in which a plurality of sets are connected in parallel between the electrode wiring member on the positive electrode side and the electrode wiring member on the negative electrode side. , A fuse section 16 may be provided. Further, a part or all of the power semiconductor element 14 may be a diode.
[0071]
　In the present invention, each embodiment can be freely combined, or each embodiment can be appropriately modified or omitted within the scope of the invention.
Explanation of reference numerals
[0072]
REFERENCE SIGNS LIST 1 power conversion device, 13 electrode wiring member, 14 power semiconductor element, 16 fuse portion, 16 a 1 upstream first stage portion, 16 a 2 downstream first stage portion, 16 b second stage portion, 20 element mold Resin, 25 sealing resin member, 26 fuse resin member, 29 semiconductor element module, 30 housing, 31 small cross section
The scope of the claims
[Claim 1]
　A power semiconductor element,
　an electrode wiring member connected to a main electrode of the power semiconductor element, a
　housing,
　a fuse portion formed on the electrode wiring member and functioning as a fuse, and a
　resin covering the fuse portion. a fuse resin member is a member,
　with the power semiconductor element, the electrode wiring member, the fuse portion, and a sealing resin member is a resin member for sealing the fuse resin member in the housing,
　wherein The fuse portion includes an upstream first-stage portion having a smaller cross-sectional area than a portion of the electrode wiring member upstream of the fuse portion along the current flow direction, and an upstream first-stage portion. A second-stage portion having a smaller cross-sectional area than the second-stage portion, and a second-stage portion having a larger cross-sectional area than the second-stage portion and having a smaller cross-sectional area than a portion of the electrode wiring member downstream of the fuse portion. 1st stage Power conversion apparatus is constituted by.
[Claim 2]
　The power semiconductor element and the electrode lead frame as the electrode wiring member are a semiconductor element module sealed with an element molding resin as a resin member, and the
　fuse portion projects outward from the element molding resin. The power converter according to claim 1, wherein the power converter is formed in a portion of the electrode lead frame.
[Claim 3]
　The length of the second stage portion in the current flow direction is the length of the upstream first stage portion in the current flow direction and the length of the downstream first stage portion in the current flow direction. The power converter according to claim 1, wherein the length is shorter than the length.
[Claim 4]
　The length of the second stage portion in the current flow direction is the length of the upstream first stage portion in the current flow direction and the length of the downstream first stage portion in the current flow direction. The power conversion device according to claim 3, wherein the power conversion device is equal to or less than half of the power.
[Claim 5]
　The first stage portion on the upstream side and the first stage portion on the downstream side have the same cross-sectional area at each position in the current flow direction. The power converter according to any one of the preceding claims.
[Claim 6]
　The power converter according to any one of claims 1 to 5, wherein the fuse resin member covers at least one surface of the second stage portion.
[Claim 7]
　7. The electrode wiring member according to claim 1, further comprising a small cross-sectional area having a smaller cross-sectional area than an upstream and downstream part in a part closer to the power semiconductor element than the fuse part. 8. The power conversion device according to claim 1.
[Claim 8]
　The said electrode wiring member is formed in plate shape, The
　said fuse part is board thickness thinner than the part of the said electrode wiring member in the upstream and downstream of the said fuse part. 3. The power converter according to claim 1.
[Claim 9]
　The power converter according to any one of claims 1 to 8, wherein the fuse portion protrudes to one side in a thickness direction from a portion of the electrode wiring member upstream and downstream of the fuse portion. .
[Claim 10]
　The power converter according to any one of claims 1 to 9, wherein the fuse resin member is made of a silicon resin having an arc-extinguishing effect of an arc discharge generated when the fuse portion is blown.
[Claim 11]
　The power converter according to any one of claims 1 to 10, wherein the fuse resin member has a lower Young's modulus than the sealing resin member.
[Claim 12]
　The power converter according to any one of claims 1 to 11, wherein the fuse resin member has a Young's modulus on the order of several tens of megapascals.