JP2021086845A - Electronic device - Google Patents

Abstract

To provide an electronic device with improved heat dissipation performance.SOLUTION: Electronic devices 1, 10 include a substrate 2, a device chip 3 mounted on one surface 2A of the substrate 2, a heat conductive member 4 provided on the other surface 2B of the substrate 2 to transfer heat of the device chip 3, and first heat radiating members 5b, 15b provided on the side of the heat conductive member 4 away from the substrate 2 and releasing the heat transferred by the heat conductive member 4, and further include heat storage materials 6, 16 provided on one side and capable of absorbing heat from the device chip 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electronic device.

Conventionally, there is known an electronic control unit in which high heat generating components such as switching elements, relays, coils and capacitors, which generate a large amount of heat during operation, are mounted on a substrate (see, for example, Patent Document 1).

In the electronic control unit disclosed in Patent Document 1, switching elements, relays, coils, capacitors and shunt resistors are mounted in a predetermined region on one surface of the substrate and in a predetermined region on the other surface of the substrate. A radiator is provided at a corresponding position via a heat conductive member. In the following, electrical components such as switching elements, relays, coils, capacitors and shunt resistors may be collectively referred to as "device chips". For example, as shown in FIG. 5, the conventional electronic control unit 101 includes a substrate 102, a device chip 103 mounted on the front surface 102A of the substrate, and a heat conductive member 104 provided on the back surface 102B of the substrate 102. It is configured to have a heat radiating body 105 provided on the heat conductive member 104, and the heat of the device chip 103 is guided to the heat radiating body 105 via the substrate 102 and the heat conductive member 104. There is.

Japanese Unexamined Patent Publication No. 2015-123846

However, in the conventional electronic control unit 101, when a momentary large current continuously flows, the normal operating temperature of the device chip 103 may be exceeded due to overheating. Therefore, it is required to improve the heat dissipation performance.

An object of the present invention is to provide an electronic device having improved heat dissipation performance.

In order to solve the above problems and achieve the object, the invention according to claim 1 is provided on a substrate, a heat generating component mounted on one surface of the substrate, and the other surface of the substrate. A heat conductive member that transfers heat of the heat generating component and a first heat radiating member that is provided on a side of the heat conductive member away from the substrate and releases heat transferred by the heat conductive member. It is an electronic device provided on the surface of the surface and further provided with a heat storage material capable of absorbing heat from the heat generating component.

The invention according to claim 2 is the invention according to claim 1, wherein a second heat radiating member is provided at a position away from the substrate with the heat storage material interposed therebetween, and the second heat radiating member is the heat storage member. It is characterized in that it is configured to release the heat stored in the material.

The invention according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the heat storage material is arranged so as to surround the heat generating component.

According to the invention of claim 1, a substrate, a heat generating component mounted on one surface of the substrate, and a heat conductive member provided on the other surface of the substrate to transfer heat of the heat generating component. A first heat radiating member which is provided on the side of the heat conductive member away from the substrate and which dissipates heat transferred by the heat conductive member is provided, and is provided on one surface and can absorb heat from the heat generating component. Further equipped with a heat storage material. That is, a part of the heat generated by the current flowing through the heat generating component is absorbed by the heat storage material, and the other part of the heat moves to the first heat radiating member via the heat conductive member, and the first It is emitted from the heat dissipation member. In this way, the heat storage material at a position capable of absorbing the heat from the heat-generating component efficiently absorbs the heat generated by the current flowing through the heat-generating component, and gradually releases the heat. According to this, the heat dissipation performance can be improved. As a result, it is possible to prevent the heating component from exceeding the normal operating temperature due to overheating.

It is a perspective view which shows the electronic device which concerns on one Embodiment of this invention. It is a figure for demonstrating the action and effect of the electronic device. It is a top view which shows the modification of the electronic device. It is sectional drawing which shows the electronic apparatus shown in FIG. It is a perspective view which shows the conventional electronic control unit.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing an electronic device according to an embodiment of the present invention. As shown in FIG. 1, the electronic device 1 according to the present embodiment includes a substantially rectangular substrate 2, a device chip 3 (heat generating component) mounted on the upper surface 2A (one surface) of the substrate 2, and a substrate. A heat conductive member 4 provided on the lower surface 2B (the other surface) of the second surface, a lower heat sink 5a (first heat radiating member), a heat storage material 6, and an upper heat sink 5b (second heat radiating member) are provided. Has been done. In the drawings, the arrows X, the arrows Y, and the arrows Z are directions orthogonal to each other. In the present embodiment, the plane extending direction of the substrate 2 is indicated by the arrow XY, and the arrow X is referred to as the "front-back direction". The arrow Y may be described as "left-right direction". Further, the thickness direction of the substrate 2 may be indicated by an arrow Z and may be described as "vertical direction".

As shown in FIG. 1, the substrate 2 is provided with a chip mounting area 21 on which the device chip 3 is mounted and a heat storage material mounting area 22 on which the heat storage material 6 is mounted. The area of the heat storage material mounting area 22 is formed to be larger than the area of the chip mounting area 21. The chip mounting region 21 is provided in the central portion of the upper surface 2A of the substrate 2. The heat storage material mounting area 22 is provided at a position adjacent to the left side (one of the left and right sides) of the chip mounting area 21. The heat storage material mounting region 22 is formed so that the dimension of the front-rear direction X is larger than the dimension of the chip mounting region 21 in the front-rear direction X, and the central portion of the heat storage material mounting region 22 in the front-rear direction X and the chip. The central portion of the mounting area 21 in the front-rear direction X is provided at a position adjacent to the left-right direction Y.

The device chip 3 is a semiconductor element that conducts or cuts off objects by turning them on and off, and is used for controlling and supplying electrical energy. When a current flows through the device chip 3, heat is generated according to the on-resistance.

The heat conductive member 4 is made of an insulating sheet having a small thermal resistance, including, for example, silicon. The heat conductive member 4 is formed so as to have substantially the same size as the substrate 2, and is provided so as to overlap the lower surface 2B of the substrate 2.

The lower heat sink 5a is made of, for example, a metal material having a low thermal resistance. The lower heat sink 5a includes a rectangular plate-shaped heat sink main body 50 provided so as to overlap the lower surface of the heat conductive member 4, and a plurality of fin portions 51 provided so as to project downward from the heat sink main body 50 in a plate shape. It is configured to have. The area of the upper surface 5A of the heat sink body 50 in the lower heat sink 5a is formed so as to be larger than the area of the lower surface 4B of the heat conductive member 4, and the lower heat sink 5a covers the entire lower surface 4B of the heat conductive member 4. It is arranged so as to cover it. The plurality of fin portions 51 are formed so that the surface area of the lower heat sink 5a is large. Further, a fan may be attached to enhance the heat dissipation effect.

The heat storage material 6 is composed of a heat storage material that stores heat by sensible heat or latent heat. The heat storage material 6 is joined to the heat storage material mounting region 22 of the substrate 2 by using solder. In the embodiment, the heat storage material 6 includes a metal case 60 having a rectangular parallelepiped outer shape and a heat storage material. The metal case 60 is made of a metal material such as aluminum. As the heat storage material, metals such as oil, iron and aluminum, ceramics, cement, bricks, paraffin, fatty acids, sugar alcohols, inorganic salt hydrates, vanadium dioxide, water and the like can be used. Here, metals such as oil, iron and aluminum, ceramics, cement and bricks store heat by sensible heat. In addition, paraffin, fatty acid, sugar alcohol, inorganic salt hydrate, and vanadium dioxide store heat by latent heat. In addition, water stores heat by sensible heat and latent heat.

The heat storage material 6 does not have to include the metal case 60. The heat storage material 6 may be entirely formed of, for example, the heat storage material. In this case, as the heat storage material for forming the heat storage material 6, a heat storage material that exhibits heat as a solid is used. For example, as the heat storage material for forming the heat storage material 6, metals such as iron and aluminum, ceramics, cement, bricks and the like can be used.

The upper heat sink 5b has substantially the same configuration as the lower heat sink 5a. That is, the upper heat sink 5b is configured to have a rectangular plate-shaped heat sink main body 50 and a plurality of fin portions 51 provided so as to project upward from the heat sink main body 50 in a plate shape. The upper heat sink 5b is formed so as to have substantially the same size as the metal case 60 of the heat storage material 6, and is provided so as to overlap the upper surface 6A of the metal case 60 of the heat storage material 6.

According to the above-described embodiment, the substrate 2 is provided on the substrate 2, the device chip 3 (heat generating component) mounted on the upper surface 2A (one surface) of the substrate 2, and the lower surface 2B (the other surface) of the substrate 2. , A heat conductive member 4 that transfers heat of the device chip 3 and a lower heat sink 5a that is provided on the side of the heat conductive member 4 away from the substrate 2 and that releases the heat transferred by the heat conductive member 4 into the air. A first heat dissipation member) and a heat storage material 6 provided on the upper surface 2A of the substrate 2 and capable of absorbing heat from the device chip 3 are further provided. That is, a part of the heat generated by the current flowing through the device chip 3 is absorbed by the heat storage material 6, and the other part of the heat moves to the lower heat sink 5a via the heat conductive member 4. , Is discharged into the air from the lower heat sink 5a. In this way, the heat storage material 6 located at a position capable of absorbing the heat from the device chip 3 efficiently absorbs the heat generated by the current flowing through the device chip 3, and the heat is gradually released. According to this, the heat dissipation performance can be improved. As a result, it is possible to prevent the device chip 3 from exceeding the normal operating temperature due to overheating.

Further, an upper heat sink 5b (second heat radiating member) is provided at a position away from the substrate 2 with the heat storage material 6 interposed therebetween so that the upper heat sink 5b releases the heat stored in the heat storage material 6 into the air. It is configured. According to this, the heat storage material 6 located at a position capable of absorbing the heat from the device chip 3 (heat generating component) efficiently absorbs the heat generated by the current flowing through the device chip 3, and the upper heat sink 5b absorbs the heat generated. , The heat stored by the heat storage material 6 is efficiently released. According to this, the heat dissipation performance can be further improved.

Further, since the heat storage material 6 is mounted on the upper surface 2A of the substrate 2, the heat storage material 6 can be installed without increasing the size in the plane extending direction XY of the substrate 2. Further, since the upper heat sink 5b is provided so as to overlap the upper surface 6A of the heat storage material 6, the upper heat sink 5b can be installed without increasing the size in the plane extending direction XY of the substrate 2.

Next, in order to confirm the effect of providing the heat storage material 6 and the upper heat sink 5b, the inventor of the present invention provides the electronic device 1 as the product of the present invention provided with the heat storage material 6 and the upper heat sink 5b, and the heat storage material. 6 and an electronic control unit 101 (shown in FIG. 5) as a conventional product without the upper heat sink 5b were prepared, and the temperature of the device chip 3 when a momentary large current was continuously applied was measured. The results are shown in FIG. In FIG. 2, the vertical axis represents the temperature of the device chip 3 and the horizontal axis represents the time. In the conventional product without the heat storage material 6 and the upper heat sink 5b, the temperature of the device chip 3 once exceeds the operating temperature when the device is normal, and then drops below the operating temperature when the device is normal, but a large current is continuously generated. As a result, the temperature peak of the device chip 3 gradually increases. That is, when a large current is continuously generated, heat cannot be completely dissipated. On the other hand, in the product of the present invention provided with the heat storage material 6 and the upper heat sink 5b, the temperature of the device chip 3 rises as a large current is continuously generated and reaches a temperature peak, but the temperature peak is reached. Is below the normal operating temperature of the device. After that, even if a large current is continuously generated, the heat storage material 6 appropriately stores the heat of the device chip 3, and the stored heat is appropriately dissipated by the upper heat sink 5b, so that the device operates normally. The result does not exceed the temperature.

In the above-described embodiment, the heat storage material 6 and the upper heat sink 5b (second heat radiating member) are provided at positions adjacent to the left side (one of the left and right sides) of the device chip 3, but the present invention describes the present invention. It is not limited to this. As shown in FIGS. 3 and 4, in the electronic device 10, the heat storage material 16 and the upper heat sink 15b (second heat radiating member) may be arranged so as to surround the four sides of the device chip 3. According to this, the heat dissipation performance can be further improved.

In addition, the best configuration, method, and the like for carrying out the present invention are disclosed in the above description, but the present invention is not limited thereto. That is, although the present invention is particularly illustrated and described primarily with respect to a particular embodiment, it does not deviate from the scope of the technical idea and purpose of the present invention and has a shape with respect to the embodiments described above. , Materials, quantities, and other detailed configurations can be modified by those skilled in the art. Therefore, the description that limits the shape, material, etc. disclosed above is merely an example for facilitating the understanding of the present invention, and does not limit the present invention. Therefore, those shapes, materials, etc. The description by the name of the member excluding a part or all of the limitation such as is included in the present invention.

1, 10 Electronic device 2 Board 2A Top surface of board (one side)
Bottom surface of 2B board (other surface)
3 Device chip (heat generating component)
4 Heat conduction member 5a Lower heat sink (first heat dissipation member)
5b, 15b Upper heat sink (second heat dissipation member)
6, 16 Heat storage material

Claims (3)

With the board
Heat-generating components mounted on one surface of the substrate and
A heat conductive member provided on the other surface of the substrate to transfer heat of the heat generating component, and
A first heat radiating member, which is provided on the side of the heat conductive member away from the substrate and emits heat transferred by the heat conductive member, is provided.
An electronic device provided on one of the surfaces and further provided with a heat storage material capable of absorbing heat from the heat generating component. A second heat radiating member is provided at a position away from the substrate with the heat storage material in between.
The electronic device according to claim 1, wherein the second heat radiating member is configured to release the heat stored in the heat storage material. The electronic device according to claim 1 or 2, wherein the heat storage material is arranged so as to surround the heat generating component.

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