JP3739739B2 - Electronic cooling unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic cooling unit used in, for example, a refrigerator, an air conditioner, and a water chiller, and more particularly to an electronic cooling unit using a Peltier element (electronic cooling element).
[0002]
[Prior art]
Among thermoelectric conversion elements, an element that cools a predetermined element by supplying electric energy is called a Peltier element or an electronic cooling element, and is used in an electronic cooling unit such as a compact refrigerator.
[0003]
As shown in FIG. 6, in the conventional electronic cooling unit, a heat absorption side electrode 102 is formed on a lower insulating substrate 100 made of alumina or the like via a heat absorption side solder layer 101, and P on the heat absorption side electrode 102. Each of the n-type semiconductor layer 103 and the n-type semiconductor layer 104 is formed. A heat radiation side electrode 105 is formed so as to connect the P-type semiconductor layer 103 and the N-type semiconductor layer 104, and an upper insulating substrate 107 made of alumina or the like is provided thereon via a heat radiation side solder layer 106. Yes.
[0004]
A large number of the P-type semiconductor layer 103 and the N-type semiconductor layer 104 are interposed in parallel between the lower insulating substrate 100 and the upper insulating substrate 107 as a pair, and are electrically connected in series to provide electronic cooling. An element group is configured.
[0005]
By passing a predetermined current through the electronic cooling unit, the lower insulating substrate 100 side absorbs heat, and its surroundings are cooled. On the other hand, since the upper insulating substrate 107 side radiates heat, heat is transferred by being radiated to the outside by means of heat radiating fins or fans.
[0006]
The outer peripheral portions of the lower insulating substrate 100 and the upper insulating substrate 107 are sealed with a sealing agent (not shown).
[0007]
[Problems to be solved by the invention]
As described above, the conventional one is soldered between the insulating substrate made of alumina ceramic or the like and the electrode and between the electrode and the P-type semiconductor layer and the N-type semiconductor layer. Thus, the warping of the insulating substrate that occurs adversely affects the electrodes and the semiconductor layer, resulting in poor connection and disconnection, and the useful life of the electronic cooling unit is short.
[0008]
An object of the present invention is to eliminate such drawbacks of the prior art and provide an electronic cooling unit having a long service life.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a first means of the present invention is an electronic cooling element in which a P-type semiconductor layer and an N-type semiconductor layer are arranged in parallel and are electrically connected by upper and lower heat absorption side electrodes and heat dissipation side electrodes. A group is interposed between the heat absorption side substrate and the heat dissipation side substrate,
A support having rigidity and poor thermal conductivity is disposed from the heat absorption side substrate to the heat dissipation side substrate so as to surround the electronic cooling element group, and the electronic cooling element group is protected by the support,
An adhesive layer having elasticity after curing is interposed between at least one of the heat absorption side electrode and the heat absorption side base and between the heat dissipation side electrode and the heat dissipation side base, so that the electrode is horizontally oriented with respect to the base and An electronic cooling unit that is displaceable in at least one of vertical directions.
[0010]
According to a second means of the present invention, there is provided an electronic cooling element group in which a P-type semiconductor layer and an N-type semiconductor layer are arranged in parallel and electrically connected by upper and lower heat absorption side electrodes and heat dissipation side electrodes, While being interposed between the heat dissipating side substrate,
A support having rigidity and poor thermal conductivity is disposed from the heat absorption side substrate to the heat dissipation side substrate so as to surround the electronic cooling element group, and the electronic cooling element group is protected by the support,
Between the heat absorption side electrode and the heat absorption side substrate and between at least one of the heat radiation side electrode and the heat radiation side substrate, an inorganic compound filler is mixed and an adhesive layer having elasticity even after curing is interposed. Is displaceable in at least one of a horizontal direction and a vertical direction with respect to the base body.
[0011]
According to a third means of the present invention, there is provided an electronic cooling element group in which a P-type semiconductor layer and an N-type semiconductor layer are arranged in parallel and electrically connected by upper and lower heat absorption side electrodes and heat dissipation side electrodes, While being interposed between the heat dissipating side substrate,
A support having rigidity and poor thermal conductivity is disposed from the heat absorption side substrate to the heat dissipation side substrate so as to surround the electronic cooling element group, and the electronic cooling element group is protected by the support,
A temperature of −60 to 250 ° C. even after curing by mixing an inorganic compound filler into a silicone-based organic compound between at least one of the heat absorption side electrode and the heat absorption side substrate and between the heat dissipation side electrode and the heat dissipation side substrate. The electrode is displaceable in at least one of a horizontal direction and a vertical direction with respect to the substrate with an adhesive layer that retains elasticity over a range.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view in which a part of the electronic cooling unit is sectioned, and FIG. 2 is an enlarged sectional view of the vicinity of the seal portion of the electronic cooling unit.
[0013]
As shown in FIG. 1, two electronic cooling element groups 3 are juxtaposed at a predetermined interval between the heat absorption side base 1 and the heat dissipation side base 2 so as to surround the electronic cooling element group 3. A support 16 having rigidity and poor thermal conductivity is interposed.
[0014]
The support 16 has, for example, a honeycomb structure having an independent air layer inside. When the space between the heat-absorbing side substrate 1 and the heat-dissipation side substrate 2 is tightened with a resin bolt (not shown) described later, the support 16 is tightened. The applied force is mainly received by the support 16 and the electronic cooling element group 3 is protected so that almost no clamping force is applied to the electronic cooling element group 3. Although not shown, the insertion hole for the bolt is formed in the heat radiation side base 2.
[0015]
In the present embodiment, a seal portion 17 is provided from the O-ring 6 and the sealant 7 as shown in FIG. It is configured.
[0016]
A groove 8 is formed in advance around the heat absorption side substrate 1 and the heat radiation side substrate 2 in contact with the O-ring 6, and a part of the O-ring 6 is in the groove 8 by the tightening force.
[0017]
The seal surface 18 is traversed from the inner peripheral side of the seal surface 18 in contact with the seal portion 17 of at least one of the heat absorption side substrate 1 and the heat dissipation side substrate 2 (in this embodiment, the heat dissipation side substrate 2). Instead, a through-hole 19 penetrating in the horizontal direction is formed outside the heat-radiating base 2. As shown in FIG. 2, the vicinity of the opening of the through hole 19 on the electrode 9 (12) side is a tapered hole having a diameter that increases toward the opening.
[0018]
In this embodiment, the through holes 19 are formed in the heat dissipation side substrate 2, but can also be formed in the heat absorption side substrate 1. However, if the through-hole 19 is formed in the heat-absorbing side substrate 1 and air (moisture) is present in the hole, there is a risk of condensation. Therefore, the through-hole 19 is formed in the heat-radiating side substrate 2 as in this embodiment. Is good.
[0019]
As shown in FIG. 1, a fin 20 made of, for example, a metal thin plate bent in a zigzag shape is integrally attached to the outside of the heat radiation side base 2. A lead body 21 is inserted into the through-hole 19 through the fins 20, and the tip of the lead body 21 is connected and fixed to the electrode 9 (12) with solder 22.
[0020]
The leading end portion of the lead body 21 is covered with a predetermined length, and the taper hole of the through-hole 19 is closed with an adhesive 23 made of, for example, silicone resin or epoxy resin, thereby removing the coating removal portion of the lead body 21. Is embedded in the adhesive 23. By embedding in the adhesive 23, it is possible to prevent the intrusion of moisture from the gap between the wire of the lead body 21 and the coating with the adhesive 23.
[0021]
As shown in FIGS. 3 and 4, the electronic cooling element group 3 includes an endothermic electrode 9 disposed at a predetermined interval, a bulk-type or film-like (thick film or thin film) P-type semiconductor layer 10, and the like. For example, it is composed of an N-type semiconductor layer 11 having a bulk shape or a film shape (thick film or thin film) and a heat radiation side electrode 12. Many P-type semiconductor layers 10 and N-type semiconductor layers 11 are arranged in parallel, and are electrically connected in series as shown in FIG.
[0022]
As described above, the electronic cooling element group 3 of the present embodiment does not use an insulating substrate made of alumina ceramic or the like. In the modular state, the heat absorption side electrode 9 is provided on one surface and the heat radiation side is provided on the other surface. The electrode 12 is exposed.
[0023]
As shown in FIG. 3, an adhesive layer 13 is interposed between the heat dissipation side substrate 2 and the heat dissipation side electrode 9, and a grease layer 14 is interposed between the heat absorption side substrate 1 and the heat absorption side electrode 9.
[0024]
For the adhesive layer 13, for example, an organic compound such as silicone alone or an organic compound mixed with an appropriate amount of a filler made of an inorganic compound such as silica, alumina, or zinc oxide is used. This adhesive layer 13 has elasticity even after curing and has good thermal conductivity, and a film thickness of 20 to 200 μm is appropriate.
[0025]
In this example, a silicone adhesive in which an appropriate amount of alumina fine particles having an average particle size of 10 μm or less is dispersed and held, and has rubber elasticity even after curing, and has a thermal conductivity of 4.5 × 10 −3 cal / cm. • sec · ° C., elongation of 30%, tensile strength of 50 kgf / cm 2, maintaining good rubber elasticity over a wide temperature range of −60 to 250 ° C. In the case of this embodiment, the heat radiation side substrate 2 and the heat radiation side electrode 12 are integrally joined by the silicone-based adhesive layer 13.
[0026]
As the grease layer 14, silicone grease is suitable. This silicone grease is preferably one in which a fine filler of an inorganic compound such as silica, alumina, zinc oxide or the like (having an average particle size of 10 μm or less) is added to the base oil by 50% by weight or more. Thus, the thermal conductivity of the silicone grease layer in which the filler is dispersed and held at a high content is as high as 6.0 × 10 −3 cal / cm · sec · ° C. or more, which is 3 × 10 −4 cal / cm of general silicone grease. -Compared to sec. ° C, the thermal conductivity is higher by one digit or more. The silicone grease layer maintains good elasticity over a wide temperature range from −55 to 200 ° C. The appropriate film thickness is 20 to 100 μm.
[0027]
The ends of the O-ring 6 are inserted into the grooves 8 provided in the bases 1 and 2, respectively, and the bases 1 and 2 are fastened with an appropriate pressure. The O-ring 6 is made of a synthetic rubber such as nitrile rubber which is difficult to pass water vapor, and the bolt is made of polyamide containing 50% glass fiber.
[0028]
In order to avoid the penetration of moisture into the unit as much as possible, the insertion hole for the fastening bolt is provided in the heat-radiating side base 2, and after the bolt is further tightened, the head of the bolt is embedded with a sealant.
[0029]
After the bolting, as shown in FIG. 1, a sealing agent 7 is applied and sealed from the outer peripheral facing portions of the substrates 1 and 2 and the groove formed by the O-ring 6 to the end surfaces of the substrates 1 and 2.
[0030]
In the case of this embodiment, a sealing agent 7 made of an epoxy resin in which hollow glass fine particles are uniformly dispersed in an amount of 20 to 65% by weight (preferably 30 to 60% by weight) is used. The hollow glass fine particles have a diameter of 20 to 130 μm, a wall thickness of 0.5 to 2 μm, an average particle specific gravity of 0.1 to 0.4, and the epoxy resin containing the hollow glass fine particles has a thermal conductivity. The rate is as low as 1 × 10 −4 cal / cm · sec · ° C.
[0031]
FIG. 5 is a diagram showing a modification of the present invention. In the case of this modification, the heat absorption side substrate 1 and the heat absorption side electrode 9 and the heat dissipation side substrate 2 and the heat dissipation side electrode 12 are bonded by an elastic silicone adhesive layer 13.
[0032]
【The invention's effect】
If an adhesive layer having elasticity even after curing is interposed between the substrate and the electrode as in the present invention so that the electrode can be displaced horizontally or (and) perpendicular to the surface of the substrate. The adverse effects of the heat history on the electrodes and the semiconductor layer are eliminated, and there is no connection failure or disconnection as in the conventional case, and a performance-stable electronic cooling unit having a long service life can be provided.
[0033]
In the electronic cooling unit described in the above embodiment, the service life can be extended by about 10 times in a thermal history test in which cooling and heating are repeated, as compared with a conventional one in which an electrode and an insulating substrate are integrated with solder. It was.
[Brief description of the drawings]
FIG. 1 is a side view, partly in section, of an electronic cooling unit according to a second embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of the vicinity of a seal portion of the electronic cooling unit.
FIG. 3 is an enlarged cross-sectional view of the vicinity of an electrode of the electronic cooling unit.
FIG. 4 is an enlarged perspective view of an electronic cooling element group.
FIG. 5 is an enlarged cross-sectional view in the vicinity of an electrode in a modification of the present invention.
FIG. 6 is an enlarged cross-sectional view of a conventional electronic cooling unit.
[Explanation of symbols]
1: heat absorption side substrate, 2: heat radiation side substrate, 3: electronic cooling element group, 6: O-ring, 7: adhesive, 8: groove, 9: heat absorption side electrode, 10: P-type semiconductor layer, 11: N-type Semiconductor layer, 12: heat radiation side electrode, 13: adhesive layer, 14: grease layer, 16: support, 17: seal part, 18: seal surface, 19: through hole, 20: fin, 21: lead body, 22 : Solder, 23: Adhesive.

Claims (3)

An electronic cooling element group in which a P-type semiconductor layer and an N-type semiconductor layer are arranged in parallel and electrically connected by upper and lower heat absorption side electrodes and heat dissipation side electrodes is interposed between the heat absorption side base and the heat dissipation side base. With
A support having rigidity and poor thermal conductivity is disposed from the heat absorption side substrate to the heat dissipation side substrate so as to surround the electronic cooling element group, and the electronic cooling element group is protected by the support,
An adhesive layer having elasticity after curing is interposed between at least one of the heat absorption side electrode and the heat absorption side base and between the heat dissipation side electrode and the heat dissipation side base, so that the electrode is horizontally oriented with respect to the base and An electronic cooling unit that is displaceable in at least one of vertical directions. An electronic cooling element group in which a P-type semiconductor layer and an N-type semiconductor layer are arranged in parallel and electrically connected by upper and lower heat absorption side electrodes and heat dissipation side electrodes is interposed between the heat absorption side base and the heat dissipation side base. With
A support having rigidity and poor thermal conductivity is disposed from the heat absorption side substrate to the heat dissipation side substrate so as to surround the electronic cooling element group, and the electronic cooling element group is protected by the support,
Between the heat absorption side electrode and the heat absorption side substrate and between at least one of the heat radiation side electrode and the heat radiation side substrate, an inorganic compound filler is mixed and an adhesive layer having elasticity even after curing is interposed. The electronic cooling unit can be displaced in at least one of a horizontal direction and a vertical direction with respect to the substrate. An electronic cooling element group in which a P-type semiconductor layer and an N-type semiconductor layer are arranged in parallel and electrically connected by upper and lower heat absorption side electrodes and heat dissipation side electrodes is interposed between the heat absorption side base and the heat dissipation side base. With
A support having rigidity and poor thermal conductivity is disposed from the heat absorption side substrate to the heat dissipation side substrate so as to surround the electronic cooling element group, and the electronic cooling element group is protected by the support,
A temperature of −60 to 250 ° C. even after curing by mixing an inorganic compound filler into a silicone-based organic compound between at least one of the heat absorption side electrode and the heat absorption side substrate and between the heat dissipation side electrode and the heat dissipation side substrate. An electronic cooling unit characterized in that an electrode is displaceable in at least one of a horizontal direction and a vertical direction with respect to a substrate through an adhesive layer that retains elasticity over a range.

Images