JP2000068565A - Peltier element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance Peltier element with a long life and high thermal transfer efficiency. SOLUTION: A plurality of P-type thermoelectric materials 3 and a plurality of N-type thermoelectric materials 4 alternately arranged between the first substrate 10a and the second substrate 10b are connected in series by a plurality of metal electrodes 8a and 8b. The end faces 5a of the P-type thermoelectric materials 3 and the N-type thermoelectric materials 4 at the first substrate side are connected to the first substrate 10a through the metal electrodes 8a, and the end faces 5b at the second substrate side are connected to the second substrate 10b through the metal electrodes 8b. The end faces 5a of the P-type thermoelectric materials 3 and the N-type thermoelectric materials 4 at the first substrate side are slipped closer to both the end sides of the first substrate 10a comparing to the end faces 5b at the second substrate side and the closer to both the ends, the larger in slippage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a Peltier device used for heating and cooling operations.

[0002]

2. Description of the Related Art The phenomenon in which heat is generated or absorbed in addition to Joule heat at a contact when a current is caused to flow by contacting different kinds of conductors or semiconductors is known as the Peltier effect.
The absorption of heat by the Peltier effect is applied to a wide range of equipment from a refrigerator to a semiconductor cooling device as a cooling action.

FIG. 3 is a sectional view of a conventional Peltier device, and FIG.
FIG. 4 is a partially enlarged sectional view showing a detailed configuration of the Peltier device of FIG. 3.

[0004] As shown in FIG. 3, the Peltier device 2 includes a first substrate 10a and a second substrate 10b arranged to face each other. A plurality of P-type thermoelectric materials 3 and N-type thermoelectric materials 4 are alternately arranged between the first substrate 10a and the second substrate 10b. The plurality of P-type thermoelectric materials 3 and the plurality of N-type thermoelectric materials 4 are connected in series by a plurality of metal electrodes 8a and 8b.

[0005] One surface of the P-type thermoelectric material 3 and one surface of the N-type thermoelectric material 4 are joined to a first substrate 10a via a metal electrode 8a. The other surfaces of the P-type thermoelectric material 3 and the N-type thermoelectric material 4 are joined to the second substrate 10b via the metal electrodes 8b. Outside the first substrate 10a and the second substrate 10b, a first heat transfer body 13a such as a heat source and a second heat
The heat transfer bodies 13b are respectively joined.

As shown in FIG. 4, a metal layer 12 is formed on opposing surfaces of a first substrate 10a and a second substrate 10b. Both surfaces of the P-type thermoelectric material 3 are joined to the metal electrodes 8a and 8b by solder 9, respectively. Similarly, both surfaces of the N-type thermoelectric material 4 are joined to the metal electrodes 8a and 8b by solder 9, respectively. In addition, the metal electrode 8
a is joined to the first substrate 10a by the solder 9.
Similarly, the metal electrode 8b is soldered to the second substrate 10b
Is joined to.

As the P-type thermoelectric material and the N-type thermoelectric material, for example, a Bi-Te system is used. Representative P
The type thermoelectric material is (Bi _0.25 Sb _0.75 ) ₂ Te ₃ , and a typical N-type thermoelectric material is Bi ₂ (Te _0.95 Se _0.05 ) ₃ .

When power is supplied to such a Peltier element 2,
Heat is transferred to the P-type thermoelectric material 3 and the N-type thermoelectric material 4 to generate a temperature difference between the first substrate 10a and the second substrate 10b, and one of the first substrate 10a and the second substrate 10b absorbs heat. Side and one side is the heat dissipation side. Therefore, it is possible to cool or heat the first heat transfer body 13a and the second heat transfer body 13b.

[0009]

However, in the conventional Peltier device 2 described above, the first substrate 1a and the second substrate 10b are thermally expanded and contracted when the first substrate 10a and the second substrate 10b are energized.
0a and metal electrode 8a, second substrate 10b and metal electrode 8b, metal electrodes 8a and 8b and P-type thermoelectric material 3, and metal electrodes 8a and 8b and N-type thermoelectric material 4 A shear stress acts on the joint with the metal. Thereby,
Shear stress also acts inside the P-type thermoelectric material 3 and the N-type thermoelectric material 4.

In particular, the first substrate 10a and the second substrate 10
The closer to both ends of b, the greater the effect of thermal expansion and thermal contraction and the greater the acting shear stress.

When the Peltier device 2 is used for a heat cycle operation in which heating and cooling are repeated, a shear stress that fluctuates according to the heat cycle acts on each of the above-mentioned portions in the Peltier device 2. As a result, the above-described portions in the Peltier element 2 are fatigued and damaged, or the performance decreases over time.

Therefore, Japanese Unexamined Patent Publication No. Hei 8-186296 discloses that the bonding between the first substrate 10a and the metal electrode 8a and the second
By using a rubber-like substance such as silicon rubber for at least one of the bonding between the substrate 10b and the metal electrode 8b,
A method for relaxing a shear stress acting in a Peltier device is disclosed. Thereby, the life of the Peltier element is improved and the performance is prevented from lowering.

However, in the above method, at least one of the space between the first substrate 10a and the metal electrode 8a and the space between the second substrate 10b and the metal electrode 8b has a relatively low thermal conductivity such as silicon rubber. Due to the presence of the substance, the cooling capacity and the heating capacity of the Peltier element decrease.

An object of the present invention is to provide a Peltier device having high performance, long life and high heat transfer efficiency.

[0015]

Means for Solving the Problems and Effects of the Invention A Peltier device according to the first invention comprises a pair of substrates arranged to face each other, a P-type thermoelectric material alternately arranged between the pair of substrates, and An N-type thermoelectric material, comprising a plurality of electrode layers that connect the P-type thermoelectric material and the N-type thermoelectric material and are respectively joined to opposing surfaces of the pair of substrates, and wherein both ends of the pair of substrates are closer to the center than to the center. One surface of each of the P-type thermoelectric materials and each of the N-type thermoelectric materials facing one of the pair of substrates is provided at a position shifted to both ends with respect to the other surface facing the other substrate. is there.

In the Peltier device according to the present invention, one surface of each P-type thermoelectric material and each N-type thermoelectric material facing one substrate is closer to both ends of the pair of substrates than at the center.
It is provided at a position shifted toward both ends with respect to the other surface facing the other substrate. Thus, in each of the P-type thermoelectric materials and each of the N-type thermoelectric materials, a shear stress is applied in advance toward one end on one surface of one substrate, and a shear stress is applied in a direction toward the center on the other substrate. Is working. Therefore, when one substrate thermally contracts, one surface of each P-type thermoelectric material and each N-type thermoelectric material on the one substrate side moves in the direction toward the center,
The shear stress in the direction toward both ends acting in advance on one surface on one substrate side is canceled. Also, when the other substrate thermally expands, the other surface of each P-type thermoelectric material and each N-type thermoelectric material on the other substrate side moves in the direction toward both ends, so that the other surface of the other substrate side This cancels out the shearing stress acting in the direction toward the center in advance.

As a result, the P-type thermoelectric material and N
It becomes possible to reduce or eliminate the shear stress acting on the mold thermoelectric material. In addition, the maximum shear stress acting on the P-type thermoelectric material and the N-type thermoelectric material can be reduced even during a heat cycle operation in which heating and cooling are repeated.

In this case, in order to reduce the shear stress,
There is no need to interpose a substance having low thermal conductivity between one substrate and the electrode layer or between the other substrate and the electrode layer.

Therefore, the performance is enhanced, the life is prolonged, and high heat transfer efficiency is obtained.

According to a second aspect of the present invention, there is provided a Peltier device comprising: a pair of substrates arranged to face each other; a P-type thermoelectric material and an N-type thermoelectric material alternately arranged between the pair of substrates; And a plurality of electrode layers joined to the opposing surfaces of the substrate in a pair, respectively, so that both end portions of the pair of substrates are closer to both ends than the central portion. The thermoelectric material is inclined.

In the Peltier device according to the present invention, each P-type thermoelectric material and each N-type thermoelectric material are inclined closer to both ends of the pair of substrates than to the center. Thereby, each P
In the type thermoelectric material and each N-type thermoelectric material, a shear stress acts in a direction toward both ends on one surface of one substrate side, and a shear stress acts in a direction toward a center portion on the other surface of the other substrate side in advance. are doing. Therefore, when one substrate thermally contracts, each P-type thermoelectric material and each N-type thermoelectric material incline in the opposite direction, so that the direction toward the both ends acting in advance on one surface of the one substrate side is reduced. The shear stress is offset by the shear stress acting due to the thermal shrinkage of one of the substrates. Further, when the other substrate thermally expands, the respective P-type thermoelectric materials and the respective N-type thermoelectric materials are inclined in opposite directions, so that the direction toward the central portion acting in advance on the other surface of the other substrate is achieved. Is offset by the shear stress acting due to the thermal expansion of the other substrate.

As a result, the P-type thermoelectric material and N
It becomes possible to reduce or eliminate the shear stress acting on the mold thermoelectric material. In addition, the maximum shear stress acting on the P-type thermoelectric material and the N-type thermoelectric material can be reduced even during a heat cycle operation in which heating and cooling are repeated.

In this case, in order to eliminate the shear stress, the thermal conductivity between one of the pair of substrates and the electrode layer bonded thereto or between the other substrate and the electrode layer bonded thereto is reduced. There is no need to intervene substances with low

Therefore, the performance is enhanced, the life is prolonged, and high heat transfer efficiency is obtained.

According to a third aspect of the present invention, there is provided a Peltier device comprising: a pair of substrates arranged to face each other; a P-type thermoelectric material and an N-type thermoelectric material alternately arranged between the pair of substrates; And a plurality of electrode layers connected to the surfaces facing the pair of substrates, respectively, and each of the P-type thermoelectric materials and each of the N-type thermoelectric materials due to thermal expansion or contraction of the pair of substrates during operation. Shear stress is applied (acted) in advance to each P-type thermoelectric material and N-type thermoelectric material in a direction opposite to the direction of the shear stress acting on the thermoelectric material.

In the Peltier device according to the present invention, each P-type thermoelectric element operates in a direction opposite to the direction of shear stress acting on each P-type thermoelectric material and each N-type thermoelectric material due to thermal expansion or thermal contraction of a pair of substrates. The material and each N-type thermoelectric material have been given shearing stress (action) in advance. Therefore,
When one substrate thermally contracts, the shear stress applied to each P-type thermoelectric material and each N-type thermoelectric material in advance is offset by the shear stress acting due to the thermal contraction. When the other substrate thermally expands, each P-type thermoelectric material and each N-type
The shear stress applied to the mold thermoelectric material in advance is offset by the shear stress acting due to thermal expansion. as a result,
It becomes possible to reduce or eliminate the shear stress acting on each P-type thermoelectric material and each N-type thermoelectric material during operation. In addition, the maximum shear stress acting on the P-type thermoelectric material and the N-type thermoelectric material can be reduced even during a heat cycle operation in which heating and cooling are repeated.

In this case, in order to reduce the shear stress,
There is no need to interpose a substance having low thermal conductivity between one of the pair of substrates and the electrode layer bonded thereto or between the other substrate and the electrode layer bonded thereto.

Therefore, the performance is enhanced, the life is extended, and high heat transfer efficiency is obtained.

[0029]

FIG. 1 is a sectional view of a Peltier device according to an embodiment of the present invention.

As shown in FIG. 1, the Peltier device 100
Are a first substrate 10a made of ceramic and a second substrate 10 made of ceramic
b. A plurality of P-type thermoelectric materials 3 and a plurality of N-type thermoelectric materials 4 are alternately arranged between the first substrate 10a and the second substrate 10b. The plurality of P-type thermoelectric materials 3 and the plurality of N-type thermoelectric materials 4 are provided at the center of the first substrate 10a and in the second
They are arranged symmetrically with respect to a central axis passing through the center of the substrate 10b.

The plurality of P-type thermoelectric materials 3 and N-type thermoelectric materials 4 are connected in series by a plurality of metal electrodes 8a and 8b. Each metal electrode 8a connects a pair of adjacent P-type thermoelectric materials 3 and N-type thermoelectric material 4, and each metal electrode 8b has a pair of N-type thermoelectric materials 4 and P-type The thermoelectric material 3 is connected.

The first substrate-side end surfaces 5a of the P-type thermoelectric material 3 and the N-type thermoelectric material 4 are connected to the first substrate 10 via metal electrodes 8a.
a. Further, the second substrate-side end surfaces 5b of the P-type thermoelectric material 3 and the N-type thermoelectric material 4 are joined to the second substrate 10b via the metal electrodes 8b.

Each P-type thermoelectric material 3 and each N-type thermoelectric material 4
The first substrate 10a and the first substrate 10a are deformed so that, when the Peltier device 100 is not operated (non-energized), the first substrate 10a and the second substrate 10b are deformed so as to incline outward toward both ends as compared with the center. It is joined to the second substrate 10b. That is, the position of the first substrate-side end surface 5a of each P-type thermoelectric material 3 and each of the N-type thermoelectric materials 4 is shifted toward both ends of the first substrate 10a with respect to the position of the second substrate-side end surface 5b. Each P-type thermoelectric material 3 and each N-type thermoelectric material 4
The amount of displacement between the first substrate side end surface 5a and the second substrate side end surface 5b is set to be larger toward both ends.

Thus, each P-type thermoelectric material 3 and each N
A first substrate 10a is provided on an end surface 5a of the mold thermoelectric material 4 on the first substrate side.
The shear stress acts in the direction toward both ends, and the magnitude of the shear stress increases toward the both ends. A shear stress in the direction toward the center of the second substrate 10b acts on the second substrate side end surface 5b of each P-type thermoelectric material 3 and each N-type thermoelectric material 4,
Its size increases as it approaches the ends.

The detailed structure of the joint between the P-type thermoelectric material 3 and the N-type thermoelectric material 4 and the metal electrodes 8a and 8b is the same as the structure shown in FIG. Further, the first and second metal electrodes 8a and 8b
The detailed configuration of the joint between the substrate 10a and the second substrate 10b is the same as the configuration shown in FIG.

When the Peltier device 100 is operated (energized), heat is transferred to the P-type thermoelectric material 3 and the N-type thermoelectric material 4, and a temperature difference between the first substrate 10a and the second substrate 10b occurs. appear. In the present embodiment, the first substrate 10a
Is the low temperature side, and the second substrate 10b is the high temperature side.

FIG. 2 is a sectional view of the Peltier device shown in FIG. 1 during operation. As shown in FIG. 2, the first substrate 10a is thermally contracted, and the second substrate 10b is thermally expanded. Therefore, the first substrate-side end surface 5a of each P-type thermoelectric material 3 and each N-type thermoelectric material 4 moves in the direction toward the center of the first substrate 10a, and the second substrate-side end surface 5b moves to both ends of the second substrate 10b. Move in the direction toward the part. As a result, contrary to the non-operating state in FIG. 1, the first substrate-side end surface 5a of each P-type thermoelectric material 3 and each N-type thermoelectric material 4 is shifted toward the center from the second substrate-side end surface 5b. Each P-type thermoelectric material 3 and each N-type thermoelectric material 4 are deformed. In addition, the shift amount is larger as the distance from both ends is increased. That is, each P-type thermoelectric material 3 and each N-type thermoelectric material 4 are deformed so that both end portions are inclined more inward than the central portion.

As a result, a shear stress in the direction toward the center of the first substrate 10a acts on the first substrate-side end surface 5a of the P-type thermoelectric material 3 and the N-type thermoelectric material 4, and the second substrate-side end surface 5b , A shear stress acts in a direction toward both ends of the second substrate 10b. The direction of these shear stresses is opposite to the direction of action when not actuated in FIG. Therefore, the shear stress acting during non-operation is offset by the shear stress acting due to the thermal contraction of the first substrate 10a and the thermal expansion of the second substrate 10b.

As described above, at the time of operation, the first substrate-side end face 5a of each P-type thermoelectric material 3 and each N-type thermoelectric material 4 and the second
By applying a shear stress in the direction opposite to the direction of the shear stress acting on the substrate side end face 5b to the first substrate side end face 5a and the second substrate side end face 5b during non-operation, the P-type thermoelectric material 3 can be operated during operation. And the shear stress acting in the N-type thermoelectric material 4 is reduced or eliminated. At the same time, the junction between the P-type thermoelectric material 3 and the metal electrodes 8a and 8b, the junction between the N-type thermoelectric material 3 and the metal electrodes 8a and 8b, the junction between the metal electrode 8a and the first substrate 10a, and the metal electrode 8b And the second substrate 10
The shear stress acting on the joint with b is also reduced or eliminated.

In particular, the P-type thermoelectric material 3 and N
When the magnitude of the shear stress acting on the first substrate side end face 5a and the second substrate side end face 5b of the mold thermoelectric material 4 is set to be the same as the magnitude of the shear stress acting during operation, the P-type thermoelectric material 3 during operation In addition, the magnitude of the maximum shear stress acting in the N-type thermoelectric material 4 can be reduced by half as compared with the conventional Peltier device.

The influence of the thermal shrinkage of the first substrate 10a increases as the distance from both ends of the first substrate 10a increases. Similarly, the second substrate 1
The effect of thermal expansion of 0b is also greater nearer to both ends of the second substrate 10b. Therefore, the P-type thermoelectric material 3 and N
The magnitude of the shear stress acting on the first substrate-side end surface 5a and the second substrate-side end surface 5b of the mold thermoelectric material 4 increases as the distance from both ends increases.

In this embodiment, the non-operating P-type thermoelectric material 3
And the first substrate-side end face 5a of the N-type thermoelectric material 4 and the second
Since the shear stress acting on the substrate-side end face 5b is increased nearer to both ends, the shear stress acting during operation can be effectively canceled.

Thus, the Peltier device 100 can be used for a heat cycle operation in which heating or cooling is repeated.
Can prevent the fatigue of each part in the Peltier device 100 and the deterioration of the performance over time.

For a device used at a substantially constant temperature, such as a refrigerator, the shear stress acting on the P-type thermoelectric material 3 and the N-type thermoelectric material 4 during operation becomes substantially zero. Non-operating P-type thermoelectric material 3 and N
It is also possible to apply a shear stress to the first substrate side end surface 5a and the second substrate side end surface 5b of the mold thermoelectric material 4.

Further, since it is not necessary to interpose a substance having low thermal conductivity between the metal electrodes 8a and 8b and the first and second substrates 10a and 10b in order to eliminate or reduce the shear stress, the Peltier element is not required. Heat transfer efficiency increases.

The method for manufacturing the Peltier device 100 is as follows.
The first substrate 10a and the second substrate 10b are set to the operating temperature, respectively, and the P-type thermoelectric material 3 and the N-type thermoelectric material 4
To join. Thereby, the first substrate-side end surface 5a and the second substrate-side end surface 5 of the P-type thermoelectric material 3 and the N-type thermoelectric material 4 are formed.
A shear stress acts on b in advance. If the temperature fluctuates during operation, the first substrate 10a is set to the lowest temperature during operation and the second substrate 10b is set to the highest temperature during operation. Also, the first substrate 10a and the second substrate 10
The Peltier element 100 can also be manufactured by bonding at least one substrate b to the P-type thermoelectric material 3 and the N-type thermoelectric material 4 while mechanically deforming the substrate.

[Brief description of the drawings]

FIG. 1 is a sectional view of a Peltier device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the Peltier device shown in FIG. 1 during operation.

FIG. 3 is a sectional view of a conventional Peltier device.

FIG. 4 is a partially enlarged sectional view showing a detailed configuration of the Peltier device of FIG. 3;

[Explanation of symbols]

 Reference Signs List 3 P-type thermoelectric material 4 N-type thermoelectric material 5a First substrate side end surface 5b Second substrate side end surface 8a Metal electrode 8b Metal electrode 10a First substrate 10b Second substrate 100 Peltier element

Claims (3)

[Claims] A pair of substrates arranged to face each other; a P-type thermoelectric material and an N-type thermoelectric material alternately arranged between the pair of substrates; a P-type thermoelectric material and the N-type thermoelectric material And a plurality of electrode layers respectively joined to opposing surfaces of the pair of substrates, and both end portions of the pair of substrates are opposed to one of the pair of substrates as compared to a central portion. A Peltier device, wherein one surface of each P-type thermoelectric material and each N-type thermoelectric material is provided at a position shifted toward both ends with respect to the other surface facing the other substrate. 2. A pair of substrates arranged so as to face each other; a P-type thermoelectric material and an N-type thermoelectric material alternately arranged between the pair of substrates; a P-type thermoelectric material and the N-type thermoelectric material And a plurality of electrode layers respectively joined to opposing surfaces of the pair of substrates. Each of the P-type thermoelectric materials and the N-type thermoelectric materials is closer to both ends of the pair of substrates than at the center. A Peltier device characterized by being inclined. 3. A pair of substrates disposed so as to face each other, a P-type thermoelectric material and an N-type thermoelectric material alternately arranged between the pair of substrates, and the P-type thermoelectric material and the N-type thermoelectric material. A plurality of electrode layers that are connected and are respectively joined to opposing surfaces of the pair of substrates, and act on each P-type thermoelectric material and each N-type thermoelectric material by thermal expansion or contraction of the pair of substrates during operation. The respective P-type thermoelectric materials and the respective N
A Peltier device, wherein a shear stress is previously applied to a thermoelectric material.