Dissimilar metal glass junction heater

Abstract

Provided is a metal heater small in heat capacity, light in weight and capable of sufficiently withstanding fluid pressure. A metal heater (6) according to the present invention comprises: a first metal substrate (10); a heating resistor layer (40) laminated on the front surface of the first metal substrate (10); a buffer layer (30) laminated on the rear surface of the first metal substrate (10); and a second metal substrate (20) laminated on the rear surface of the buffer layer (30) and having a thermal expansion coefficient larger than the thermal expansion coefficient of the first metal substrate (10). The buffer layer (30) preferably includes a first buffer layer (31) laminated on the first metal substrate (10) side, a second buffer layer (33) laminated on the second metal substrate (20) side, and an intermediate buffer layer (32) laminated between the first buffer layer (31) and the second buffer layer (33).

Description

Dissimilar metal glass bonding heater

[0001] This invention relates to a dissimilar metal-glass bonding heater. More specifically, it relates to a dissimilar metal-glass bonding heater (hereinafter referred to as a metal heater) that has better thermal conductivity, smaller heat capacity, is lightweight, and has excellent strength against fluid pressure.

[0002] In recent years, electric vehicles have begun to adopt heaters with stainless steel substrates (hereinafter referred to as "steel heaters") as battery heaters and coolant heaters. Because steel heaters use stainless steel as the substrate, they have excellent strength. The inventors have proposed a steel heater using stainless steel as the substrate (see, for example, Examples 1 to 6 of Patent Document 1). The heater described in Patent Document 1 comprises a long base portion, a resistive heating wiring portion having a plurality of parallel wires that conduct electricity and generate heat, formed on the surface side or inside the base portion in an electrically insulated state from the base portion, and at least two power supply terminal portions, and a power supply electrode portion that electrically connects one terminal portion and the other terminal portion via the resistive heating wiring portion in order to supply power to the resistive heating wiring portion, the resistive heating wiring portion containing a material with a resistance temperature coefficient of 500 to 4,400 ppm / °C, and the parallel wiring containing an inclined rectangular pattern. With this heater, localized temperature rises in the resistive heating wiring section during use are suppressed, allowing for stable heat treatment of the object being heat-treated, regardless of its size, while suppressing temperature unevenness.

[0003] International Publication No. 2013 / 073276

[0004] However, currently, there is a demand for battery heaters, particularly coolant heaters, to have better thermal conductivity, smaller heat capacity, and lighter weight. Therefore, it is necessary to make the heater substrate as thin as possible while still being able to withstand fluid pressure. The present invention aims to solve the above problems and to provide a metal heater that has better thermal conductivity, smaller heat capacity, is lightweight, and can withstand fluid pressure sufficiently.

[0005] The present invention is as follows: 1. A metal heater comprising: a first metal substrate; a heat-generating resistor layer laminated on the surface of the first metal substrate; a buffer layer laminated on the back surface of the first metal substrate; and a second metal substrate laminated on the back surface of the buffer layer and having a coefficient of thermal expansion greater than that of the first metal substrate. 2. The metal heater according to 1. above, wherein B < M2 when the coefficient of thermal expansion of the buffer layer is B and the coefficient of thermal expansion of the second metal substrate is M2. 3. The metal heater according to 2. above, wherein M1 < B < M2 when the coefficient of thermal expansion of the first metal substrate is M1. 4. The metal heater according to 1. or 2. above, wherein the material of the first metal substrate is stainless steel and the material of the second metal substrate is aluminum or an aluminum alloy. 5. The buffer layer comprises a first buffer layer laminated on the first metal substrate side, a second buffer layer laminated on the second metal substrate side, and an intermediate buffer layer laminated between the first buffer layer and the second buffer layer, wherein when the thermal expansion coefficient of the first buffer layer is B1, the thermal expansion coefficient of the intermediate buffer layer is B2, and the thermal expansion coefficient of the second buffer layer is B3, B1 < B2 < B3, the metal heater as described in 2. above. 6.9.1 × 10 －６ ( / °C) < B2 < 24.0 × 10 －６5. The metal heater according to 5. above, wherein the temperature is ( / °C). 7. The metal heater according to 1. above, wherein a glass reinforcing layer is further laminated between the first metal substrate and the buffer layer and / or between the second metal substrate and the buffer layer. 8. The metal heater according to 1. or 7. above, wherein a heat-soothing layer having a higher thermal conductivity than the first metal substrate and the second metal substrate is further laminated at least one location between the laminated substrates and each layer. 9. The metal heater according to 8. above, wherein the buffer layer and / or the glass reinforcing layer laminated adjacent to the heat-soothing layer are provided with a plurality of through holes penetrating from front to back, and the inside of the through holes is filled with a thermally conductive material. 10. The metal heater according to 1. above, wherein a solder layer is further laminated between the first metal substrate and the buffer layer or between the second metal substrate and the buffer layer. 11. 11. The metal heater according to 7., wherein a solder layer is further laminated between the first metal substrate and the glass reinforcement layer, between the second metal substrate and the glass reinforcement layer, or between the buffer layer and the glass reinforcement layer. 12. The metal heater according to 10. or 11., wherein a metal layer is laminated adjacent to the solder layer. 13. The metal heater according to 10. or 11., wherein the solder layer is laminated in a planar manner between each of the layers, and the solder layer has a slit portion cut out inward from the lateral outer edge. 14. The metal heater according to 1. or 2., further comprising a protective layer covering the heat-generating resistor layer. 15. The metal heater according to 1. or 2., wherein the heat-generating resistor layer consists of a heat-generating resistance wire formed on an insulating layer. 16. The metal heater according to 1. or 2., wherein the first metal substrate on which the heat-generating resistor layer is laminated and the second metal substrate are joined via the buffer layer. 17. The metal heater according to 16. wherein the buffer layer is laminated on the back surface of the first metal substrate and / or on the surface of the second metal substrate, and then the first metal substrate on which the heat-generating resistor layer is laminated and the second metal substrate are joined together. 18. The metal heater according to 10. or 11. wherein the first metal substrate on which the heat-generating resistor layer is laminated and the second metal substrate are joined together via the solder layer.19. The metal heater according to 12, wherein the metal layer is laminated on a layer adjacent to the solder layer, and the first metal substrate on which the heat-generating resistor layer is laminated and the second metal substrate are joined via the solder layer. 20. The metal heater comprising: a first metal substrate; a heat-generating resistor layer laminated on the surface of the first metal substrate; a buffer layer laminated on the surface of the heat-generating resistor layer; and a second metal substrate laminated on the surface of the buffer layer and having a coefficient of thermal expansion greater than that of the first metal substrate. 21. The metal heater according to 20, wherein a solder layer is further laminated between the second metal substrate and the buffer layer. 22. The metal heater according to 22, wherein a metal layer is laminated adjacent to the solder layer. 23. A method for manufacturing a metal heater comprising a first metal substrate, a second metal substrate having a coefficient of thermal expansion greater than that of the first metal substrate, and a buffer layer laminated between the first metal substrate and the second metal substrate, the method comprising the steps of: laminating a heat-generating resistor layer on the surface of the first metal substrate; and joining the back of the first metal substrate on which the heat-generating resistor layer is laminated and the front of the second metal substrate via the buffer layer. 24. The method for manufacturing a metal heater according to 23, wherein the buffer layer comprises a plurality of layers, and the buffer layer is placed on the back of the first metal substrate and / or the front of the second metal substrate and joined together. 25. The method for manufacturing a metal heater according to 24, wherein at least one of the plurality of layers constituting the buffer layer is an unfired layer, and the buffer layer is formed by heating the laminate including the unfired layer. 26. The method for manufacturing a metal heater according to 25, wherein the buffer layer comprises three layers, and the middle layer in the front-back direction of the buffer layer is unfired. A method for manufacturing a metal heater as described above.27. A method for manufacturing a metal heater comprising: a first metal substrate; a second metal substrate having a coefficient of thermal expansion greater than that of the first metal substrate; and a buffer layer laminated between the first metal substrate and the second metal substrate, the method comprising: a step of laminating a heat-generating resistor layer on the surface of the first metal substrate; a step of laminating the buffer layer on the back surface of the first metal substrate on which the heat-generating resistor layer is laminated and / or on the surface of the second metal substrate; and a step of joining the first metal substrate and the second metal substrate via a solder layer between the buffer layer laminated on the back surface of the first metal substrate and the second metal substrate, between the buffer layer laminated on the surface of the second metal substrate and the first metal substrate, or between the buffer layer laminated on the back surface of the first metal substrate and the buffer layer laminated on the surface of the second metal substrate. 28. The metal heater according to 27, wherein the metal layer is laminated on a layer adjacent to the solder layer, and then the first metal substrate and the second metal substrate are joined via the solder layer.

[0006] The metal heater of the present invention comprises a first metal substrate, a heat-generating resistor layer laminated on the surface of the first metal substrate, and a second metal substrate laminated on the back surface of the first metal substrate and having a thermal expansion coefficient greater than that of the first metal substrate. Therefore, the first metal substrate provides the heating function, and the second metal substrate allows for a small heat capacity and lightweight design while maintaining strength. By laminating the first and second metal substrates, a metal heater can be made that has better thermal conductivity, a smaller heat capacity, is lightweight, and can withstand fluid pressure sufficiently. Furthermore, the presence of a buffer layer laminated between the first and second metal substrates alleviates stress and strain between them. In addition, if the thermal expansion coefficient of the buffer layer is B and the thermal expansion coefficient of the second metal substrate is M2, and B < M2, the lamination of the buffer layer can alleviate the difference in thermal expansion between the first and second metal substrates, thereby alleviating stress and strain between them. Furthermore, if the thermal expansion coefficient of the first metal substrate is M1, and M1 < B < M2, then the first metal substrate, buffer layer, and second metal substrate are laminated in the order from the front side to the back side. This allows the thermal expansion coefficient to gradually increase from the first metal substrate to the second metal substrate, effectively mitigating the difference in thermal expansion between the first and second metal substrates. Moreover, if the material of the first metal substrate is stainless steel and the material of the second metal substrate is aluminum or an aluminum alloy, these materials are extremely suitable as they result in appropriate thermal expansion coefficients. The buffer layer consists of a first buffer layer laminated on the first metal substrate side, a second buffer layer laminated on the second metal substrate side, and an intermediate buffer layer laminated between the first and second buffer layers. If the thermal expansion coefficient of the first buffer layer is B1, the intermediate buffer layer is B2, and the second buffer layer is B3, then if B1 < B2 < B3, the difference in thermal expansion coefficients can be mitigated even more gradually. Furthermore, 9.1 x 10 －６ ( / °C) < B2 < 24.0 × 10 －６If the temperature is ( / °C), the difference in thermal expansion coefficients can be mitigated more specifically. Furthermore, if a glass reinforcing layer is further laminated between the first metal substrate and the buffer layer and / or between the second metal substrate and the buffer layer, the first and second metal substrates can be reinforced. In addition, if a heat-soothing layer with a higher thermal conductivity than the first and second metal substrates is further laminated at least one location between the laminated substrates and each layer, the thermal fluctuations formed by the heat-retaining resistor layer can be smoothed out. Furthermore, if multiple through-holes penetrating from front to back are provided in the buffer layer and / or glass reinforcing layer laminated adjacent to the heat-soothing layer, and a thermally conductive material is filled inside the through-holes, the heat emitted from the heat-retaining resistor layer can be efficiently transferred to the second metal substrate, further smoothing out the thermal fluctuations. In addition, if a solder layer is further laminated between the first metal substrate and the buffer layer or between the second metal substrate and the buffer layer, the first and second metal substrates can be reliably joined by the solder layer at a relatively low temperature. Furthermore, if a solder layer is further laminated between the first metal substrate and the glass reinforcement layer, between the second metal substrate and the glass reinforcement layer, or between the buffer layer and the glass reinforcement layer, the solder layer allows for reliable bonding of the first and second metal substrates at a relatively low temperature. Also, if a metal layer is laminated adjacent to the solder layer, the connection between the first and second metal substrates can be reliably established, and the bonding strength can be increased. In addition, if the solder layer is laminated in a planar manner between each layer and has a slit cut out from the outer edge on the side toward the inside, it is possible to mitigate deformation due to stress when stress is applied to the metal heater. Furthermore, if there is a protective layer covering the heat-generating resistor layer, the heat-generating resistor layer can be protected. Moreover, if the heat-generating resistor layer consists of heat-generating resistance wires formed on an insulating layer, the heat generated from the heat-generating resistor can be used efficiently. Furthermore, when a first metal substrate with a heat-generating resistor layer laminated on it and a second metal substrate are joined together via a buffer layer, a metal heater can be appropriately manufactured that mitigates the difference in thermal expansion between the first and second metal substrates.Furthermore, by mitigating the difference in thermal expansion, the stress in the direction that hinders the bonding of the first and second metal substrates is also reduced, preventing the first and second metal substrates from delaminating. Moreover, if a buffer layer is laminated on the back surface of the first metal substrate and / or the surface of the second metal substrate before bonding the first metal substrate with the heat-generating resistor layer to the second metal substrate, a metal heater with even more appropriate mitigation of the difference in thermal expansion can be manufactured. Additionally, if the first metal substrate with the heat-generating resistor layer to the second metal substrate is bonded via a solder layer, the first and second metal substrates can be bonded at a relatively low temperature, minimizing the risk of thermal damage to heat-sensitive components and substrates. Furthermore, since large-scale equipment is not required and working conditions can be relaxed, the process can be made inexpensively and the process can be simplified. Furthermore, when the metal layer is laminated on a layer adjacent to the solder layer, and then the first metal substrate on which the heat-generating resistor layer is laminated and the second metal substrate are joined via the solder layer, the connection between the first metal substrate and the second metal substrate can be reliably ensured, and the bonding strength can be increased. In addition, the metal heater of the present invention comprises a first metal substrate, a heat-generating resistor layer laminated on the surface of the first metal substrate, a buffer layer laminated on the surface of the heat-generating resistor layer, and a second metal substrate laminated on the surface of the buffer layer and having a coefficient of thermal expansion greater than that of the first metal substrate. As a result, the heater function is provided by the first metal substrate, and the second metal substrate allows for a small heat capacity and weight reduction while maintaining strength. Furthermore, by laminating the first metal substrate and the second metal substrate, a metal heater can be made that has better thermal conductivity, a small heat capacity, is lightweight, and can withstand fluid pressure sufficiently. Furthermore, the presence of a buffer layer between the first and second metal substrates relieves stress and strain between them. Additionally, if a solder layer is further laminated between the second metal substrate and the buffer layer, the solder layer allows for reliable bonding of the first and second metal substrates at a relatively low temperature.Furthermore, when a metal layer is laminated adjacent to a solder layer, the connection between the first metal substrate and the second metal substrate can be reliably established, and the bonding strength can be increased. In addition, the present invention relates to a method for manufacturing a metal heater comprising a first metal substrate, a second metal substrate having a coefficient of thermal expansion greater than that of the first metal substrate, and a buffer layer laminated between the first metal substrate and the second metal substrate, and comprises the steps of laminating a heat-generating resistor layer on the surface of the first metal substrate and joining the back of the first metal substrate on which the heat-generating resistor layer is laminated to the front of the second metal substrate via the buffer layer. As a result, the buffer layer mitigates the difference in thermal expansion between the first metal substrate and the second metal substrate, and the stress strain generated between the first metal substrate and the second metal substrate is reduced. Therefore, the adhesion strength between the first metal substrate and the second metal substrate can be strengthened. Furthermore, the buffer layer comprises multiple layers, and since the buffer layer is positioned on the back of the first metal substrate and / or on the front of the second metal substrate and bonded, the difference in thermal expansion between the first and second metal substrates is mitigated, ensuring a secure bond between the two. Moreover, since at least one of the multiple layers constituting the buffer layer is an unfired layer, and the laminate including the unfired layer is heated to form it, the first and second metal substrates can be bonded with greater adhesion strength. Additionally, the buffer layer comprises three layers, and the middle layer in the front-back direction of the buffer layer is unfired, allowing the first and second metal substrates to be bonded with greater adhesion strength.Furthermore, the present invention relates to a method for manufacturing a metal heater comprising a first metal substrate, a second metal substrate having a coefficient of thermal expansion greater than that of the first metal substrate, and a buffer layer laminated between the first and second metal substrates, the method comprising the steps of: laminating a heat-generating resistor layer on the surface of the first metal substrate; laminating the buffer layer on the back surface of the first metal substrate on which the heat-generating resistor layer is laminated and / or on the surface of the second metal substrate; and joining the first metal substrate and the second metal substrate via a solder layer between the buffer layer laminated on the back surface of the first metal substrate and the second metal substrate, between the buffer layer laminated on the surface of the second metal substrate and the first metal substrate, or between the buffer layer laminated on the back surface of the first metal substrate and the buffer layer laminated on the surface of the second metal substrate. As a result, the first and second metal substrates can be joined at a relatively low temperature, minimizing the risk of thermal damage to heat-sensitive components and substrates. Moreover, since it does not require large-scale equipment and the working conditions can be relaxed, it is possible to perform the work at low cost and simplify the process. Furthermore, if a metal layer is laminated on the solder layer and adjacent to it, and then the first metal substrate and the second metal substrate are joined via the solder layer, the connection between the first and second metal substrates can be made more secure, and the bonding strength can be increased.

[0007] This is a schematic cross-sectional view of a metal heater according to an embodiment. This is a schematic cross-sectional view of a metal heater according to another embodiment. This is a schematic cross-sectional view of a metal heater according to yet another embodiment. This is a schematic cross-sectional view of a metal heater according to yet another embodiment. This is a schematic cross-sectional view of a metal heater according to yet another embodiment. This is a schematic cross-sectional view of a metal heater according to yet another embodiment. This relates to the manufacturing process of the metal heater according to the embodiment, where (a) is a schematic explanatory diagram showing the step of forming a buffer layer material on the back surface of the first metal substrate and the front surface of the second metal substrate, respectively, (b) is a step of joining the buffer layer materials together, and (c) is a schematic explanatory diagram showing the step of forming a buffer layer by firing. This is a schematic explanatory diagram showing the step of forming a buffer layer material on the front surface of the second metal substrate. This is a schematic explanatory diagram showing the step of forming a buffer layer material on the back surface of the first metal substrate. This is a schematic cross-sectional view of a metal heater according to another embodiment. This is a schematic cross-sectional view of a metal heater according to yet another embodiment. This is a schematic cross-sectional view of a metal heater according to yet another embodiment. This is a diagram showing the planar shape of a solder layer. This is a diagram showing the planar shape of another solder layer. This is a diagram showing the planar shape of yet another solder layer. This figure shows the planar shape of another solder layer. This is a schematic explanatory diagram relating to the manufacturing process of the metal heater of the embodiment, where (a) is the step of laminating solder paste on the back surface of the metal layer laminated on the first metal substrate and on the surface of the metal layer laminated on the second metal substrate, (b) is the step of adhering the solder paste laminated in (a) to the surface, and (c) is the step of forming a solder layer by reflow. This is a schematic explanatory diagram showing the step of laminating solder paste on the surface of the metal layer laminated on the second metal substrate. This is a schematic explanatory diagram showing the step of laminating solder paste on the back surface of the metal layer laminated on the first metal substrate. This is a flowchart showing the manufacturing method of the metal heater in three steps. This is a flowchart of the first metal substrate laminate formation step. (a) is a flowchart showing each step of the glass reinforcement layer / heat resistance layer formation step, (b) is a schematic explanatory diagram showing the step of forming the insulating layer and the glass reinforcement layer, and (c) is a schematic explanatory diagram showing each step of forming the heat resistance layer.(a) is a flowchart showing each step of the protective layer formation step and the first buffer layer formation step, (b) is a schematic explanatory diagram showing the protective layer formation step, and (c) is a schematic explanatory diagram showing the first buffer layer formation step. This is a flowchart of the second metal substrate laminate formation step. (a) is a flowchart showing the glass reinforcement layer formation step and the second buffer layer formation step on the second metal substrate, (b) is a schematic explanatory diagram showing the glass reinforcement layer formation step, and (c) is a schematic explanatory diagram showing the second buffer layer formation step. (a) is a flowchart showing the intermediate buffer layer formation and bonding step, (b) is a schematic explanatory diagram showing the step of printing the intermediate buffer layer material, (c) is a schematic explanatory diagram showing the step of bonding the two layers, and (d) is a schematic explanatory diagram showing the step of firing to produce a metal heater. This is a schematic explanatory diagram showing the step of forming the intermediate buffer layer material on the surface of the second buffer layer. This is a schematic diagram illustrating the process of forming an intermediate buffer layer material on the back surface of the first buffer layer. This is a flowchart illustrating the manufacturing method of a metal heater having conductive parts. (a) is a flowchart illustrating each step of the conductive part formation process, (b) is a schematic diagram illustrating the process of forming a laminate having through holes, and (c) is a schematic diagram illustrating the process of forming conductive parts. (a) is a flowchart illustrating each step of the intermediate buffer layer formation and bonding process, (b) is a schematic diagram illustrating the process of printing the intermediate buffer layer material, and (c) is a schematic diagram illustrating the process of joining laminates together to produce a metal heater. This is another flowchart illustrating the manufacturing method of a metal heater in three steps. This is a flowchart illustrating the metal / solder layer formation and bonding process. (a) is a flowchart illustrating the first metal substrate metal layer formation process and its schematic diagram, and (b) is a flowchart illustrating the second metal substrate metal layer formation process and its schematic diagram. (a) is a flowchart showing the solder layer lamination process and the solder bonding process; (b) is a schematic diagram showing the process of printing solder paste; (c) is a schematic diagram showing the process of bringing two solder pastes into close contact; and (d) is a schematic diagram showing the process of joining solder pastes by reflow to manufacture a metal heater.This is a schematic diagram illustrating the process of laminating solder paste onto the surface of a second metal substrate laminate. This is a schematic diagram illustrating the process of laminating solder paste onto the back surface of a first metal substrate laminate. This is a schematic cross-sectional view showing a modified example of the metal heater according to the embodiment. This is a schematic cross-sectional view showing another modified example of the metal heater according to the embodiment. This is yet another schematic cross-sectional view showing yet another modified example of the metal heater according to the embodiment.

[0008] The present invention will be described in detail below with reference to embodiments. The matters described herein are illustrative and intended to illustrate embodiments of the present invention, and are intended to provide what is considered to be the most effective and straightforward explanation of the principles and conceptual features of the present invention. In this regard, it is not intended to show structural details of the present invention beyond what is necessary for a fundamental understanding of the invention, and the description, in conjunction with the drawings, will make it clear to those skilled in the art how some forms of the present invention are actually realized.

[0009] <Metal Heater> As shown in Figure 1, the metal heater 1 is a heater for heating an object to be heated by heat emitted from a heat-generating resistor layer 40, and comprises a first metal substrate 10, a heat-generating resistor layer 40 laminated on the surface of the first metal substrate 10, and a second metal substrate 20 laminated on the back side of the first metal substrate 10 and having a larger coefficient of thermal expansion than the first metal substrate 10. A buffer layer 30 is laminated between the first metal substrate 10 and the second metal substrate 20 to mitigate the difference in thermal expansion between the first metal substrate 10 and the second metal substrate 20. In other words, the metal heater 1 has a structure in which the second metal substrate 20, buffer layer 30, first metal substrate 10, and heat-generating resistor layer 40 are laminated in that order from the back side to the front side. By laminating the second substrate layer 20 on the back side of the first metal substrate 10, the strength is maintained by the first metal substrate 10, and the heat capacity is reduced by the second substrate layer 20, making it possible to reduce weight. As a result, a metal heater can be made that has a small heat capacity, is lightweight, and can withstand fluid pressure sufficiently. Furthermore, by laminating a buffer layer 30 between the first metal substrate 10 and the second metal substrate 20, stress strain generated between the first metal substrate 10 and the second metal substrate 20 can be alleviated.

[0010] [1] First metal substrate The first metal substrate 10 is placed on top of the metal heater 1 and preferably has excellent strength. The thickness is not particularly limited, but is preferably 200 to 700 μm, and more preferably 300 to 600 μm. The material of the metal constituting the first metal substrate is not particularly limited as long as it has a smaller coefficient of thermal expansion than the second metal substrate 20, but steel and the like can be used. Among these, stainless steel can be suitably used in the present invention. The type of stainless steel is not particularly limited, but ferritic stainless steel and austenitic stainless steel are preferred. Furthermore, among these stainless steels, varieties with particularly excellent heat resistance and oxidation resistance are preferred. For example, SUS430, SUS436, SUS444, SUS316L, SUS304, etc. These may be used alone or in combination of two or more. Furthermore, when stainless steel is used, the thermal expansion coefficient of the first metal substrate 10 is preferably in the range of 9.9 ( / °C) to 17.3 ( / °C), and if SUS430 is used, the thermal expansion coefficient is 10.4 × 10 －６ The temperature is ( / °C). Furthermore, the first metal substrate 10 may be formed of a clad material or a bimetal from the viewpoint of heat exchange efficiency. The type of clad material or bimetal is not particularly limited, but for example, it can have a first metal plate made of steel and a second metal plate with a higher thermal conductivity than the first metal plate. Stainless steel can preferably be used as the first metal plate. On the other hand, for example, silver, copper, gold, aluminum, tungsten, nickel, etc., or an alloy containing at least one of these metals can be used as the second metal plate. Furthermore, as the clad material or bimetal, for example, a form in which the first metal plate is bonded to only one surface of the second metal plate (e.g., SUS-Cu, etc.), a form in which the first metal plate is bonded to both surfaces of the second metal plate (e.g., SUS-Cu-SUS, etc.), or a form in which the second metal plate is bonded to both surfaces of the first metal plate (e.g., Cu-SUS-Cu, etc.) can be used. Furthermore, it is also possible to use one that has three or more types of metal plates.

[0011] [2] Second Metal Substrate The second metal substrate 20 is placed below the metal heater 1 and preferably has better thermal conductivity, a smaller heat capacity, and is lightweight. The thickness is not particularly limited, but is preferably 0.3 to 3 mm, and more preferably 0.6 to 2.7 mm. The metal material constituting the second metal substrate 20 is not particularly limited as long as it has a larger coefficient of thermal expansion than the first metal substrate 10, but aluminum, magnesium, and alloys of these metals can be used. These may be used individually or in combination of two or more. Among these, aluminum, magnesium, and their alloys (aluminum alloy, magnesium alloy, Al-Mg alloy, etc.) have high thermal conductivity and low specific gravity, so adopting them will suit the purpose of reducing the heat capacity and weight of the metal heater. Here, if aluminum is used, the coefficient of thermal expansion is 24.5 × 10 －６ It is ( / °C).

[0012] [3] Heating resistor layer The heating resistor layer 40 is a member for causing the metal heater to generate heat, and is laminated on the surface of the first metal substrate 10. The heating resistor layer 40 is not particularly limited as long as it is a layer that generates heat by energization. As shown in FIG. 1, it can be composed of an insulating layer 43, a heating resistance wire 41 formed on the insulating layer 43, a power supply terminal 42 for supplying power to the heating resistance wire 41, and a power supply wire (not shown) connecting the heating resistance wire 41 and the power supply terminal 42. As the material of the power supply terminal 42 and the power supply wire, for example, silver having a high conductivity can be used. The thickness of the power supply terminal 42 and the power supply wire is not particularly limited, but is preferably 8 to 5 μ m, and more preferably 10 to 40 μ m. The heating resistance wire 41 can generate heat uniformly over the entire surface of the substrate by adopting a zigzag shape combining parallel wiring and folded-back wiring. The thickness of the heating resistance wire 41 is not particularly limited, but is preferably 8 to 40 μ m, and more preferably 10 to 30 μ m. The material of the heating resistance wire 41 is not particularly limited, but a conductive material that can generate heat according to the resistance value by energization can be used. This conductive material is not particularly limited, and for example, silver, copper, platinum, palladium, rhodium, tungsten, molybdenum, rhenium, ruthenium, etc. can be used. These may be used alone or in combination of two or more. When two or more are used in combination, they can be made into an alloy. For example, silver-palladium alloy, silver-platinum alloy, platinum-rhodium alloy, silver-ruthenium alloy, etc. can be used. The material of the insulating layer 43 is not particularly limited as long as it is a material having insulating properties. For example, glass, ceramics, glass-ceramics, etc. are preferable. Among these, considering that the material constituting the first metal substrate 10 is metal, glass is preferable from the viewpoint of thermal expansion balance, and crystallized glass and semi-crystallized glass are more preferable. Specifically, SiO ２ -Al ２ O ３- MO-based glass is preferred. Here, MO is an oxide of an alkaline earth metal (MgO, CaO, BaO, SrO, etc.). The thickness of the insulating layer 43 is not particularly limited, but is preferably 80 to 120 μm, and more preferably 90 to 110 μm. Note that the insulating layer 43 in the heat-generating resistor layer 40 shown in Figures 10 to 12, which will be described later, functions as a buffer layer, and the insulating layer 43 may or may not function as a buffer layer.

[0013] [4] Buffer layer The buffer layer 30 is a layer laminated between the first metal substrate 10 and the second metal substrate 20 to mitigate the difference in thermal expansion between the first metal substrate 10 and the second metal substrate 20. The buffer layer 30 is not particularly limited as long as the objective of mitigating the difference in thermal expansion is achieved, but it is preferable that B < M2 when the thermal expansion coefficient of the first metal substrate 10 is M1, the thermal expansion coefficient of the buffer layer 30 is B, and the thermal expansion coefficient of the second metal substrate 20 is M2. Also, M1 may be greater than, less than, or the same as B, but it is preferable that it is less than B. Furthermore, it is even more preferable that M1 < B < M2, in which case the first metal substrate 10, buffer layer 30, and second metal substrate 20 are laminated in the order from the front side to the back side, so that the thermal expansion coefficient can be gradually increased from the first metal substrate 10 to the second metal substrate 20, and the difference in thermal expansion between the first metal substrate 10 and the second metal substrate 20 can be effectively mitigated. Furthermore, in either of the above cases, a glass reinforcing layer, described later, can be provided between the first metal substrate 10 and the buffer layer 30. If B < M1, the thermal expansion coefficient of this glass layer may be set to, for example, less than B, thereby gradually increasing the thermal expansion coefficient between the first metal substrate 10 and the buffer layer 30. Alternatively, a glass reinforcing layer may be provided between the second metal substrate 20 and the buffer layer 30, and the thermal expansion coefficient between the second metal substrate 20 and the buffer layer 30 may be adjusted. The thermal expansion coefficient of the buffer layer 30 is 9.0 × 10⁻⁶. －６ ( / °C) < B < 24.0 × 10 －６ It is preferable that the temperature is ( / °C), and 12.0 × 10 －６ (°C / °C) < B < 21.0 × 10 －６ It is more preferable that the temperature is ( / °C), and 15.0 × 10 －６ ( / °C) < B < 20.0 × 10 －６It is even more preferable that the temperature is ( / °C).

[0014] Furthermore, the buffer layer 30 can consist of multiple layers. For example, as in the metal heater 2 shown in Figure 2, the buffer layer 30 consists of a first buffer layer 31 laminated on the first metal substrate 10 side, a second buffer layer 33 laminated on the second metal substrate 20 side, and an intermediate buffer layer 32 laminated between the first buffer layer 31 and the second buffer layer 33. It is preferable that B1 < B2 < B3 when the thermal expansion coefficient of the first buffer layer 31 is B1, the thermal expansion coefficient of the intermediate buffer layer 32 is B2, and the thermal expansion coefficient of the second buffer layer 33 is B3. With this configuration, the difference in thermal expansion between the first metal substrate 10 and the second metal substrate 20 is reduced in stages, and the difference in thermal expansion can be mitigated more gradually.

[0015] The first buffer layer 31 is a layer formed on the back side of the first metal substrate 10 by a high-temperature process. For example, if the first metal substrate 10 is stainless steel, it is preferably formed by a process at 800 to 900°C, and more preferably at 820 to 880°C. The thermal expansion coefficient of the first buffer layer 31 is preferably greater than that of stainless steel and smaller than that of the intermediate buffer layer 32 described later. There are no particular limitations on the material in the range of B1, but the thermal expansion coefficient is preferably 9.0 × 10⁻⁶. －６ ( / °C) < B1 < 18.5 × 10 －６ It is preferable that the material has a temperature of ( / °C). For example, glass, ceramics, glass-ceramics, etc. are preferred. Glass is particularly preferred from the viewpoint of the thermal expansion balance between the first buffer layer 31 and the first metal substrate 10, and crystallized glass and semi-crystallized glass are preferred. Specifically, SiO ２ - Al ２ O ３ - MO-based glass is preferred. Here, MO is an oxide of an alkaline earth metal (MgO, CaO, BaO, SrO, etc.). The thickness of the first buffer layer 31 is not particularly limited, but is preferably 10 to 20 μm, and more preferably 13 to 17 μm.

[0016] The second buffer layer 33 is a layer formed on the surface of the second metal plate layer 20 by a low-temperature process. For example, if the second metal substrate 20 is aluminum, it is preferably formed by a 500-520°C process, and more preferably by a 505-515°C process. The thermal expansion coefficient of the second buffer layer 33 is preferably smaller than that of aluminum and larger than that of the intermediate buffer layer 32 described later. There are no particular limitations on the material in the range of B3, but the thermal expansion coefficient is preferably 12.0 × 10⁻⁶. －６ ( / °C) < B3 < 22.0 × 10 －６ It is preferable that the material has a temperature of ( / °C). For example, glass, ceramics, glass-ceramics, etc. are preferred. Glass is particularly preferred from the viewpoint of the thermal expansion balance between the second buffer layer 33 and the second metal substrate 20, and crystallized glass and semi-crystallized glass are preferred. Specifically, SiO ２ - Al ２ O ３ - MO-based glass is preferred. Here, MO is an oxide of an alkaline earth metal (MgO, CaO, BaO, SrO, etc.). The thickness of the second buffer layer 33 is not particularly limited, but is preferably 10 to 20 μm, and more preferably 13 to 17 μm.

[0017] The intermediate buffer layer 32 is a layer laminated between the first buffer layer 31 and the second buffer layer 33. For example, when the first metal substrate 10 is stainless steel and the second metal substrate 20 is aluminum, it is preferably formed by a 490-510°C process, and more preferably by a 495-505°C process. The thermal expansion coefficient of the intermediate buffer layer 32 is preferably greater than that of the first buffer layer 31 and smaller than that of the second buffer layer 33. There are no particular limitations on the materials in the range of B2, but the thermal expansion coefficient is preferably 9.1 × 10⁻⁶. －６ ( / °C) < B2 < 24.0 × 10 －６ It is preferable that the temperature is ( / °C), and 9.5 × 10 －６ ( / °C) < B2 < 21.4 × 10 －６ It is even more preferable that the temperature is ( / °C), and 10.5 × 10 －６ ( / °C) < B2 < 20.0 × 10 －６It is even more preferable that the material has a temperature of ( / °C). For example, glass, ceramics, glass-ceramics, etc. are preferred. Glass is particularly preferred from the viewpoint of the thermal expansion balance of the first buffer layer 31 and the intermediate buffer layer 32, and the second buffer layer 33 and the intermediate buffer layer 32, and crystallized glass and semi-crystallized glass are preferred. Specifically, SiO ２ - Al ２ O ３ - MO-based glass is preferred. Here, MO is an oxide of an alkaline earth metal (MgO, CaO, BaO, SrO, etc.). ２ O, Na ２ O, K ２ It is preferable that it does not contain or contains only a small amount of O). The thickness of the intermediate buffer layer 32 is not particularly limited, but is preferably 10 to 20 μm, and more preferably 13 to 17 μm.

[0018] The above-described embodiment of the buffer layer 30 is just one example; the first buffer layer 31, the intermediate buffer layer 32, and the second buffer layer 33 can each be formed into multiple layers to adjust the coefficient of thermal expansion and create even finer, more stepwise layers.

[0019] [5] Glass Reinforcement Layers As shown in Figure 3 of the metal heater 3, it is preferable to laminate a glass reinforcement layer 51 between the first metal substrate 10 and the buffer layer 30, and to further laminate a glass reinforcement layer 52 between the second metal substrate 20 and the buffer layer 30. This makes it possible to reinforce the first metal substrate 10 and / or the second metal substrate 20. Note that only one of the glass reinforcement layers 51 or 52 may be laminated. The material of the glass reinforcement layers 51 and 52 is not particularly limited as long as it has insulating properties, but it can be the same as the material of the insulating layer 43. The thickness of the glass reinforcement layers 51 and 52 is not particularly limited, but it is preferably 10 to 20 μm, and more preferably 13 to 17 μm. Note that the glass reinforcement layers 51 and 52 shown in Figures 10 to 12, which will be described later, function as buffer layers, and the glass reinforcement layers 51 and 52 may or may not function as buffer layers.

[0020] [6] Protective layer As shown in Figure 4 of the metal heater 4, it is preferable to further provide a protective layer 60 that covers the heat-generating resistor layer 40. The protective layer 60 can protect the heat-generating resistor layer 40 from the outside. The protective layer 60 is not intended for insulation, but its material is preferably glass, ceramics, glass-ceramics, etc., similar to the insulating layer 43. Glass is particularly preferred from the viewpoint of the thermal expansion balance between the protective layer 60 and the stainless steel substrate as the first metal substrate 10, and crystallized glass and semi-crystallized glass are preferred. Specifically, SiO ２ - Al ２ O ３ - MO-based glass is preferred. Here, MO is an oxide of an alkaline earth metal (MgO, CaO, BaO, SrO, etc.). The thickness of the protective layer 60 is not particularly limited, but is preferably 40 to 120 μm, and more preferably 50 to 110 μm. The protective layer 60 may consist of one layer or multiple layers. The total thickness including the heat-retaining resistor layer 40 and the protective layer 60 is not particularly limited, but is preferably 60 to 180 μm, more preferably 65 to 175 μm, and even more preferably 125 to 175 μm. The protective layer 60 shown in Figures 39 and 40, which will be described later, functions as a buffer layer, and the protective layer 60 may or may not function as a buffer layer.

[0021] [7] Heat Uniform Layer As shown in Figure 5 of the metal heater 5, it is preferable to further laminate a heat uniform layer 71 (711, 712, 713, 714) having a higher thermal conductivity than the first metal substrate 10 and the second metal substrate 20 at at least one location between the substrate and each layer. By having a heat uniform layer 71, the thermal fluctuations formed by the heat-generating resistor layer 40 can be smoothed out. More specifically, the heat uniform layer 71 of the metal heater 5 shown in Figure 5 is laminated as follows: a heat uniform layer 711 between the first metal substrate 10 and the glass reinforcement layer 51, a heat uniform layer 712 between the glass reinforcement layer 51 and the first buffer layer 31, a heat uniform layer 713 between the first buffer layer 31 and the intermediate buffer layer 32, and a heat uniform layer 714 between the intermediate buffer layer 32 and the second buffer layer 33. However, the location and number of the heat uniform layer 71 are not particularly limited and can be appropriately selected according to the actual situation. The thickness of each of the uniform heating layers 71 (711, 712, 713, 714) is not particularly limited, but is preferably 1 to 250 μm, and more preferably 3 to 130 μm. That is, if there is a drop in the heating temperature, it can be raised to the same temperature as the surrounding area, and if there is a spike in the heating temperature, it can be lowered to the same temperature as the surrounding area, thereby leveling out the thermal fluctuations. This is particularly suitable when the heat-generating resistance layer 40 is formed using heat-generating resistance wires 41 having a predetermined pattern shape, in order to level out the thermal fluctuations caused by this pattern shape. That is, by having a pattern shape, areas where heat-generating resistance wires 41 are present and areas where they are not are created, and thermal fluctuations are formed where the areas where heat-generating resistance wires 41 are present are hotter than the areas where they are not. Such thermal fluctuations can be leveled out by passing through the uniform heating layer 71, and the temperature difference can be reduced.

[0022] The heat-stable layer 71 can be formed from a material with a higher thermal conductivity than the materials constituting the first metal substrate 10 and the second metal substrate 20. Specifically, silver, copper, gold, or alloys containing at least one of these metals can be used as the thermally conductive metal. These thermally conductive metals may be used individually or in combination of two or more. The heat-stable layer 71 can be formed in any way. Specifically, the heat-stable layer 71 can be provided as a plating layer (electroless plating layer, electroplating layer, composite plating layer, etc.). Alternatively, the heat-stable layer 71 can be formed by printing a paste containing a thermally conductive material and then baking the printed coating. For example, a printing paste containing metal particles (metal powder) can be used as the thermally conductive material. In this case, the printing paste may also contain a vehicle for pasteurization and glass or ceramic components as a co-foundation, in addition to the metal particles.

[0023] As shown in Figure 6, in the metal heater 6, a buffer layer 30 and glass reinforcement layers 51 and 52 are laminated adjacent to the heat uniforming layer 71, and multiple through holes 73h, 74h, 75h, and 76h that penetrate from front to back are provided in the buffer layer 30 and glass reinforcement layers 51 and 52. The inside of each through hole 73h, 74h, 75h, and 76h can be filled with a thermally conductive material to form conductive portions 73, 74, 75, and 76. By providing conductive portions 73, 74, 75, and 76 in this way, the heat generated from the heat-generating resistor layer 40 can be efficiently transferred to the second metal substrate 20, the heat fluctuations can be leveled, and an even more efficient metal heater can be made.

[0024] [8] Metal heater joined via a buffer layer The metal heater 1 shown in Fig. 1 can be formed by joining a first metal substrate 10 with a heat generating resistor layer 40 laminated thereon and a second metal substrate 20 via a buffer layer 30 (including bonding). That is, the buffer layer 30 can be disposed on the back surface of the first metal substrate 10 and / or the front surface of the second metal substrate 20 in an uncured state, and then the first metal substrate 10 with the heat generating resistor layer 40 laminated thereon and the second metal substrate 20 can be joined. As shown in Fig. 7(a), a buffer layer material 30a is formed, for example, by printing on the back surface of the first metal substrate 10 with the heat generating resistor layer 40 laminated thereon, and a buffer layer material 30b is similarly formed by printing on the front surface of the second metal substrate 20. Then, as shown in Fig. 7(b), the buffer layer material 30a and the buffer layer material 30b are joined to form a buffer layer material layer 30c to form an unfired buffer layer body 1A. And as shown in Fig. 7(c), the metal heater 1 can be manufactured by firing the unfired buffer layer body 1A.

[0025] Also, as shown in Fig. 8, a buffer layer material 30c is similarly formed by printing on the front surface of the second metal substrate 20. Then, the back surface of the first metal substrate 10 is joined by being brought into close contact with the buffer layer material 30c to form an unfired laminate 1A shown in Fig. 7(b). And as shown in Fig. 7(c), the metal heater 1 can be manufactured by firing the unfired buffer layer body 1A. Also, as shown in Fig. 9, a buffer layer material 30c is similarly formed by printing on the back surface of the first metal substrate 10. Then, the back surface of the first metal substrate 10 is joined by being brought into close contact with the buffer layer material 30c to form an unfired buffer layer body 1A shown in Fig. 7(b). And as shown in Fig. 7(c), the metal heater 1 can be manufactured by firing the unfired laminate 1A.

[0026] [9] Solder layer and metal layer As shown in Figure 10, the metal heater 80 can be configured such that a glass reinforcing layer 51 is laminated as a buffer layer on the back side of the first metal substrate 10, and a solder layer 90 is laminated between the glass reinforcing layer 51 and the second metal substrate 20. Metal layers 91, 91 are laminated between the solder layer 90 and the glass reinforcing layer 51, and between the solder layer 90 and the second metal substrate 20, adjacent to the solder layer 90. Here, the solder layer 90 is interposed between the glass reinforcing layer 51 and the second metal substrate 20 for the purpose of joining the first metal substrate 10 and the second metal substrate 20. The thickness of the solder layer 90 is not particularly limited, but is preferably 10 to 300 μm, and more preferably 20 to 100 μm. Lead-free solder, eutectic solder, etc. can be used as the solder for the solder layer 90, but the type of solder used is not particularly limited. Furthermore, the solder layer 90 is preferably formed by printing solder paste onto the metal layer 91, which will be described later, but it may also be formed by, for example, plating or preforming.

[0027] Here, the planar shape of the solder layer 90 is not particularly limited, but as shown in FIG. 13, it can be in a rectangular form. Specifically, the solder layer 90 is not laminated on the outer edge portion of the second metal substrate 20 and has a rectangular form with a vertical and horizontal width smaller than that of the second metal substrate 20. Further, as shown in FIG. 14, the planar shape of the solder layer 90 may be a rectangular form with curved corners. Furthermore, it is also possible to have a solder layer 90 in which four slit portions 92 are formed by cutting vertically inward from each side on the side of the solder layer 90 shown in FIGS. 13 and 14 (see FIGS. 15 and 16). By forming the slit portions 92, when stress is applied to the metal heaters 80, 81, 82, it becomes possible to relieve the deformation due to the stress. When the shapes of the metal heaters 80, 81, 82 are not rectangular, it is preferable to appropriately change the planar shape of the solder layer 90 according to the shapes of the metal heaters 80, 81, 82. Also, the number of the slit portions 92 formed in the solder layer 90 is not limited to four, and two may be formed on each side to make eight, or other numbers may be used. Furthermore, the slit portions 92 may be formed in a diagonal direction instead of a direction perpendicular to each side of the solder layer 90.

[0028] The metal layer 91 is laminated on the bonding surfaces of each layer adjacent to the solder layer 90 in order to make the bonding by the solder layer 90 more reliable. The thickness of the metal layer 91 is not particularly limited, but for example, it is preferably 5 to 50 μm, and more preferably 8 to 30 μm. As the material of the metal layer, silver, copper, gold, nickel, or an alloy containing at least one of these metals can be used. The method for forming the metal layer 91 is not particularly limited. Specifically, when laminating the metal layer 91 on the first metal substrate 10 side, after printing a paste-like metal material, the metal layer 91 can be formed by baking the printed material at a high temperature of 800 to 900 °C. Also, when laminating the metal layer 91 on the second metal substrate 20 side, after printing a paste-like metal material, the metal layer 91 may be formed by baking the printed material at a low temperature of 510 to 550 °C, or the metal layer 91 may be formed by causing metal particles to collide at high speed by the AD method (aerosol deposition method).

[0029] Furthermore, as shown in Figure 11, the metal heater 81 can be configured such that a glass reinforcing layer 52 is laminated as a buffer layer on the surface side of the second metal substrate 20, and a solder layer 90 is laminated between the glass reinforcing layer 52 and the first metal substrate 10. Also, metal layers 91, 91 are laminated between the solder layer 90 and the glass reinforcing layer 52, and between the solder layer 90 and the first metal substrate 10, adjacent to the solder layer 90. The material, thickness, and formation method of the solder layer 90 and metal layers 91 in the metal heater 81 are the same as in the case of the metal heater 80. Furthermore, as shown in Figure 12, the metal heater 82 can be configured such that, in addition to the configuration of the metal heater 80, a glass reinforcing layer 52 is laminated between the second metal substrate 20 and the metal layer 91 laminated on the back side of the solder layer 90. In the metal heater 82 as well, metal layers 91, 91 are laminated between the solder layer 90 and the glass reinforcing layer 51 and glass reinforcing layer 52, adjacent to the solder layer 90. The materials, thickness, and formation method of the solder layer 90 and the metal layer 91 in the metal heater 81 are the same as in the case of the metal heater 80.

[0030]

[10] Metal heater joined via a solder layer The metal heater 80 shown in Figure 10 can be formed by joining a first metal substrate 10, on which a heat-generating resistor layer 40, a protective layer 60, a glass reinforcement layer 51, and a metal layer 91 are laminated, and a second metal substrate 20 on which a metal layer 91 is laminated, via a solder layer 90. That is, the solder layer 90 can be formed by printing, for example, a paste-like solder onto the back surface of the metal layer 91 laminated on the first metal substrate 10 side and / or the surface of the metal layer 91 laminated on the second metal substrate 20 side, and then joining the first metal substrate 10 and the second metal substrate 20 in close contact by reflow. Specifically, as shown in Figure 17(a), the metal layer 91 is laminated on the back surface of the first metal substrate 10, on which a heat-generating resistor layer 40, a protective layer 60, and a glass reinforcement layer 51 are laminated, and solder paste 90a is laminated on the back surface of this metal layer 91 by printing. Then, a metal layer 91 is laminated onto the surface of the second metal substrate 20, and solder paste 90b is similarly laminated onto the surface of this metal layer 91 by printing. Next, as shown in Figure (b), solder paste 90a and solder paste 90b are brought into close contact to form solder paste 90c, thereby forming a solder layer laminate 80A. Then, as shown in Figure (c), the metal heater 80 can be manufactured by reflowing the solder layer laminate 80A. Alternatively, the metal layer 91 and solder paste 90a may be laminated onto the back surface of the first metal substrate 10, on which the heat-generating resistor layer 40, protective layer 60, and glass reinforcement layer 51 are laminated. After reflowing and cooling the laminate including the first metal substrate 10, the metal layer 91 and solder paste 90b may be brought into close contact with the second metal substrate 20, on which the metal layer 91 and solder paste 90b are laminated, and then the entire laminate including the first metal substrate 10 and the second metal substrate 20 may be reflowed again. Alternatively, the second metal substrate 20, on which the metal layer 91 and solder paste 90b are laminated, may be reflowed and cooled, then brought into close contact with the laminate including the first metal substrate 10, and then the entire laminate including the first metal substrate 10 and the second metal substrate 20 may be reflowed again.Furthermore, after reflowing and cooling the laminate including the first metal substrate 10, the second metal substrate 20, on which the metal layer 91 and solder paste 90b are laminated, may also be reflowed and cooled. Then, the laminates on the first metal substrate 10 side and the second metal substrate 20 side may be brought into close contact, and the entire laminate including the first metal substrate 10 and the second metal substrate 20 may be reflowed again.

[0031] Furthermore, as shown in Figure 18, a metal layer 91 is laminated on the surface of the second metal substrate 20, and solder paste 90c is printed onto the surface of this metal layer 91. Then, the metal layer 91 is laminated on the back surface of the first metal substrate 10, on which the heat-generating resistor layer 40, protective layer 60, and glass reinforcement layer 51 are laminated. Next, the metal layer 91 laminated on the first metal substrate 10 side is brought into close contact with the solder paste 90c laminated on the second metal substrate 20 side to form the solder layer laminate 80A shown in Figure 17(b). Then, as shown in Figure 17(c), the metal heater 80 can be manufactured by reflowing the solder layer laminate 80A. Furthermore, as shown in Figure 19, a metal layer 91 is laminated on the back surface of the first metal substrate 10, on which the heat-generating resistor layer 40, protective layer 60, and glass reinforcement layer 51 are laminated, and solder paste 90c is printed onto the back surface of this metal layer 91. Then, the metal layer 91 is laminated on the surface of the second metal substrate 20. Next, the solder paste 90c laminated on the first metal substrate 10 side is brought into close contact with the metal layer 91 laminated on the second metal substrate 20 side to form the solder layer laminate 80A shown in Figure 17(b). Then, as shown in Figure 17(c), the metal heater 80 can be manufactured by reflowing the solder layer laminate 80A. In the case of the metal heaters 81 and 82 shown in Figures 11 and 12, similar to the metal heater 80, solder pastes 90a, 90b, and 90c are laminated by printing onto the back surface of the metal layer 91 laminated on the first metal substrate 10 side and / or the surface of the metal layer 91 laminated on the second metal substrate 20 side, and then the first metal substrate 10 and the second metal substrate 20 are brought into close contact via the solder pastes 90a, 90b, and 90c and reflowed to manufacture the metal heaters 81 and 82. Furthermore, in the case of metal heaters 81 and 82, when solder pastes 90a and 90b are laminated on the first metal substrate 10 side and the second metal substrate 20 side respectively, and then the two laminates are brought into close contact, the laminate including the first metal substrate 10 may be reflowed and cooled, then brought into close contact with the second metal substrate 20 on which the metal layer 91 and solder paste 90b are laminated, and then the entire laminate including the first metal substrate 10 and the second metal substrate 20 may be reflowed again.Alternatively, the laminate including the second metal substrate 20 may be reflowed and cooled, then brought into close contact with the laminate including the first metal substrate 10, and the entire laminate including the first metal substrate 10 and the second metal substrate 20 may be reflowed again. Furthermore, the laminate including the first metal substrate 10 may be reflowed and cooled, then the laminate including the second metal substrate 20 may be reflowed and cooled, the two laminates may be brought into close contact, and the entire laminate including the first metal substrate 10 and the second metal substrate 20 may be reflowed again.

[0032] <Method for Manufacturing Metal Heaters> The method for manufacturing metal heaters of the present invention will be described in more detail below with reference to Figures 20 to 37, using metal heaters 4, 6, and 82 as examples. The manufacturing methods shown below are illustrative, and the manufacturing method of the present invention is not limited to these examples. Furthermore, the method for manufacturing metal heaters of the present invention can be applied to the manufacture of the metal heaters of the present invention.

[0033] [1] Method for Manufacturing Metal Heater 4 The materials used in the manufacture of the metal heater 4 and the thickness of each layer of the manufactured metal heater 4 are as described in the metal heater section above and will be omitted here. The manufacturing process of the metal heater 4 consists of the "first metal substrate laminate formation process," the "second metal substrate laminate formation process," and the "intermediate buffer layer formation and bonding process," as shown in Figure 20. (1) First Metal Substrate Laminate Formation Process The first metal substrate laminate formation process consists of three steps, as shown in Figure 21: a glass reinforcement layer / heating resistor layer formation process, a protective layer formation process, and a first buffer layer formation process. (1-1) Glass Reinforcement Layer / Heat Resistance Layer Formation Process The glass reinforcement layer / heating resistor layer formation process is a process of forming an insulating layer 43 and a glass reinforcement layer 51 on the front and back surfaces of the first metal substrate 10, respectively. Note that the glass reinforcement layer is not necessarily required, so if a glass reinforcement layer is not provided, the glass reinforcement layer formation process is unnecessary. The glass reinforcement layer 51 and the heat-retaining resistor layer 40 are formed by the procedure shown in the glass reinforcement layer / heat-retaining resistor layer formation process in Figure 22(a). Specifically, as shown in Figure 22(b), a first metal plate layer 10 (for example, stainless steel) is prepared, and an insulating layer material is formed on the surface and a glass reinforcement layer material on the back surface, for example by screen printing. Then, it is dried. There are no particular limitations on the drying conditions, but it is preferable to heat it at a temperature of 110 to 130°C under atmospheric conditions, and more preferably at a temperature of 115 to 125°C. The heating time is preferably 10 to 30 minutes, and more preferably 15 to 25 minutes. Next, it is fired by heating. There are no particular limitations on the heating conditions, but it is preferable to heat it at a temperature of 800 to 900°C under atmospheric conditions, and more preferably at a temperature of 830 to 870°C. The heating time is preferably 8 to 12 minutes. The temperature profile of the above drying and heating conditions is hereinafter referred to as the "high-temperature profile". The process of printing, drying, and firing the insulating layer material and the glass reinforcement layer material is preferably carried out repeatedly using the high-temperature profile described above, as shown in Figure (a). Through the above process, an insulating layer 43 is formed on the surface of the first metal plate layer 10, and a glass reinforcement layer 51 is formed on the back surface.

[0034] Next, as shown in Figure (c), a power supply terminal 42 and a power supply wire (not shown) are formed on the insulating layer 43. The material for the power supply terminal 42 can be a low-resistance material, such as silver. The same applies to the material for the power supply wire. It is preferable to form both the power supply terminal 42 and the power supply wire simultaneously by screen printing, but other forming methods may be used. After forming the unfired power supply terminal and unfired power supply wire by printing, they are dried and then fired. This drying and firing is performed using the high-temperature profile described above. Next, a heat-generating resistance wire 41 is formed. It is preferable to form the heat-generating resistance wire 41 by screen printing of the heat-generating resistance wire material, but other forming methods may be used. After the unfired heat-generating resistance wire is formed by printing, it is dried and fired. This drying and firing is also performed using the high-temperature profile described above. In this way, the heat-generating resistance layer 40 shown in Figure (c) is formed.

[0035] (1-2) Protective layer formation process The protective layer formation process is a process of forming a protective layer 60 on the first metal substrate 10 on which the heat-generating resistor layer 40 and the glass reinforcement layer 51 are laminated. The protective layer 60 is formed by the procedure shown in the protective layer formation process in Figure 23(a). Specifically, as shown in Figure 23(b), the protective layer material is printed so as to cover the heat-generating resistor layer 40, and the protective layer 60 is formed by drying and firing using the high-temperature profile described above. The process of printing the protective layer material → drying → firing is preferably repeated using the high-temperature profile described above, as shown in Figure 23(a). After going through the protective layer formation process described above, the first metal substrate laminate 4a shown in Figure 23(b) is obtained.

[0036] (1-3) First buffer layer formation step The first buffer layer formation step is a step of laminating a first buffer layer 31 on the back surface of the first metal substrate 10 (first metal substrate laminate 4a) on which the heat-generating resistor layer 40, the glass reinforcement layer 51, and the protective layer 60 are laminated. The first buffer layer 31 is formed by the procedure shown in the first buffer layer formation step in Figure 23(a). Specifically, as shown in Figure 23(c), the first buffer layer material is printed on the back surface of the glass reinforcement layer 51, and then dried and fired using the high-temperature profile described above to form the first buffer layer 31 as shown in Figure 23(c). The first metal substrate laminate 4A is thus manufactured.

[0037] (2) Second Metal Substrate Laminate Formation Process The second metal substrate laminate formation process consists of a "glass reinforcement layer formation process" and a "second buffer layer formation process," as shown in Figure 24. (2-1) Glass Reinforcement Layer Formation Process The glass reinforcement layer formation process is a process of forming a glass reinforcement layer 52 on the surface of the second metal substrate 20. A glass reinforcement layer is not necessarily required, so if a glass reinforcement layer 52 is not provided, this process is unnecessary. The glass reinforcement layer 52 is formed by the procedure shown in the glass reinforcement layer formation process in Figure 25(a). Specifically, as shown in Figure 25(b), a second metal substrate 20 (for example, aluminum) is prepared, and a glass reinforcement layer material is formed on the surface, for example, by screen printing. The glass reinforcement layer material may be formed using a method other than screen printing. Then, it is dried. There are no particular limitations on the drying conditions, but it is preferable to heat it at a temperature of 110 to 130°C under atmospheric conditions, and more preferably at a temperature of 115 to 125°C. Furthermore, the heating time is preferably 10 to 30 minutes, and more preferably 15 to 25 minutes. Next, the material is fired by heating. There are no particular limitations on the heating conditions, but it is preferably heated at a temperature of 500 to 520°C under atmospheric conditions, and more preferably at a temperature of 505 to 510°C. Furthermore, the heating time is preferably 8 to 12 minutes. The temperature profile of the above drying and heating conditions is hereinafter referred to as the "low temperature profile". The process of printing the glass reinforced layer material → drying → firing is preferably repeated using the low temperature profile, as shown in Figure (a). The glass reinforced layer 52 is formed by drying and firing using the low temperature profile. After the glass reinforced layer formation process described above, the second metal substrate laminate 4b shown in Figure (b) is obtained. (2-2) Second buffer layer formation process The second buffer layer formation process is a process of forming a second buffer layer 33 on the surface of the second metal substrate 20 on which the glass reinforced layer 52 is laminated. The second buffer layer 33 is formed by the procedure shown in the second buffer layer formation step in Figure 25(a). As shown in Figure 25(c), the second buffer layer material is printed onto the surface of the glass reinforcement layer 52, and the second buffer layer 33 is formed by drying and firing using the low-temperature profile described above. The second metal substrate laminate 4B is then manufactured.It is also possible to omit either the first buffer layer 31 or the second buffer layer 33, or both.

[0038] (3) Intermediate buffer layer formation and bonding process The intermediate buffer layer formation and bonding process is a process of forming a metal heater 4 by bonding (including lamination) the first metal substrate laminate 4A produced in (1) and the second metal substrate laminate 4B produced in (2) via an intermediate buffer layer material. (3-1) Intermediate buffer layer formation and bonding process, part 1 The intermediate buffer layer formation and bonding process can be carried out in the procedure shown in Figure 26(a). Specifically, as shown in Figure 26(b), an intermediate buffer layer material layer 32a is formed on the back surface of the first metal substrate laminate 4A by printing. Similarly, an intermediate buffer layer material layer 32b is formed on the surface of the second metal substrate laminate 4B by printing. Note that the intermediate buffer layer material layers 32a and 32b may be formed using methods other than printing. Then, the first metal substrate laminate 4A on which the intermediate buffer layer material layer 32a is formed and the second metal substrate laminate 4B on which the intermediate buffer layer material layer 32b is formed are dried. There are no particular limitations on the drying conditions, but it is preferable to heat at a temperature of 110 to 130°C under atmospheric conditions, and more preferably at a temperature of 115 to 125°C. The heating time is preferably 10 to 30 minutes, and more preferably 15 to 25 minutes. If the first buffer layer 31 and / or the second buffer layer 33 are not provided, the intermediate buffer layer material layer 32a is formed on the back surface of the first metal substrate 10 or the glass reinforcement layer 51, and the intermediate buffer layer material layer 32b is formed on the surface of the second metal substrate 20 or the glass reinforcement layer 52. As shown in Figure (c), the dried intermediate buffer layer material layer 32a formed on the first metal substrate laminate 4A and the dried intermediate buffer layer material layer 32b formed on the second metal substrate laminate 4B are joined (bonded) to form an unfired bonded body 4C having an intermediate buffer layer material layer 32c. That is, the first metal substrate laminate 4A and the second metal substrate laminate 4B are bonded together here. Next, the unfired bonded body 4C is fired by heating. There are no particular limitations on the heating conditions, but it is preferable to heat it at a temperature of 490 to 510°C under atmospheric conditions, and more preferably at a temperature of 495 to 505°C. The heating time is preferably 8 to 12 minutes. The temperature profile of the above drying and heating conditions is hereinafter referred to as the "buffer profile".The heating temperatures in the "high temperature profile," "low temperature profile," and "buffer profile" are within the temperature range described above, but it is preferable that the temperature decreases in the order of "high temperature profile," "low temperature profile," and "buffer profile." Thus, by firing the unfired intermediate buffer layer material layer 32a and the unfired intermediate buffer layer material layer 32b, the bonded first metal substrate laminate 4A and the second metal substrate laminate 4B are firmly joined through these fired layers, and the metal heater 4 shown in Figure (d) is manufactured. The same applies to the following joining steps 2 and 3. Alternatively, either or both of the dried intermediate buffer layer material layer 32a formed on the first metal substrate laminate 4A and the dried intermediate buffer layer material layer 32b formed on the second metal substrate laminate 4B may be fired before joining the first metal substrate laminate 4A and the second metal substrate laminate 4B.

[0039] (3-2) Intermediate buffer layer formation and joining process, part 2 The intermediate buffer layer formation and joining process can also be carried out by the procedure shown in Figure 27. An intermediate buffer layer material layer 32c is formed on the surface of the second metal substrate laminate 4B by printing and then dried. The intermediate buffer layer material layer 32c may be formed by a method other than printing. Then, the back surface of the first metal substrate laminate 4A and the dried intermediate buffer layer material layer 32c formed on the second metal substrate laminate 4B are joined (including bonding) to form an unfired joined body 4C having the intermediate buffer layer material layer 32c (see Figure 26(c)). Next, the unfired joined body 4C is fired by heating to produce a metal heater 4. Drying and firing are carried out according to the "buffer profile" described above. Alternatively, the intermediate buffer layer material layer 32c may be fired first, and then the back surface of the first metal substrate laminate 4A and the second metal substrate laminate 4B may be joined. Alternatively, the back surface of the first metal substrate laminate 4A and the second metal substrate laminate 4B may be joined without providing the intermediate buffer layer material layer 32c. (3-3) Intermediate buffer layer formation and joining process, part 3 The intermediate buffer layer formation and joining process can also be carried out by the procedure shown in Figure 28. The intermediate buffer layer material layer 32c is formed on the back surface of the first metal substrate laminate 4A by printing and then dried. The intermediate buffer layer material layer 32c may be formed by a method other than printing. Then, the dried intermediate buffer layer material layer 32c formed on the back surface of the first metal substrate laminate 4A and the surface of the second metal substrate laminate 4B are joined (including bonding) to form an unfired joined body 4C having the intermediate buffer layer material layer 32c (see Figure 26(c)). Next, the unfired joined body 4C is fired by heating to produce the metal heater 4. Drying and firing are carried out according to the "buffer profile" described above. Alternatively, the intermediate buffer layer material layer 32c may be fired before joining the back surface of the first metal substrate laminate 4A to the second metal substrate laminate 4B.

[0040] [2] Method for Manufacturing Metal Heater 6 As shown in Figure 6, the metal heater 6 is formed by further adding a heat-soothing layer 71 (711, 712, 713, 714) and conductive parts 73, 74, 75, 76 penetrating between each layer to the metal heater 4. The following explanation will focus on the differences from the method for manufacturing the metal heater 4. As shown in Figure 29, the method for manufacturing the metal heater 6 includes a conductive part formation step and an intermediate buffer layer formation and joining step. (1) Conductive Part Formation Step The materials used in the manufacturing of the metal heater 6 and the thickness of each layer of the manufactured metal heater 6 are the same as those described in the metal heater section above and will be omitted here. The conductive part formation step is carried out in the procedure shown in Figure 30(a). Specifically, as shown in Figure 30(b), the first metal substrate laminate 6A differs from the first metal substrate laminate 4A shown in Figure 26 in that it includes a heat-soothing layer 71 and through holes 73h, 74h, 75h, 76h. To form the first metal substrate laminate 6A, as shown in Figure 30(b), a paste containing a thermally conductive material as a heat-soothing layer material is printed on the back surface of the first metal substrate 10, and then the printed coating is baked to form a heat-soothing layer 711H having through holes 73h, 74h, 75h, and 76h. Then, a glass reinforcement layer 51H is laminated on the back surface of the heat-soothing layer 711H. Next, a heat-soothing layer 712H is formed on the back surface of the glass reinforcement layer 51H in the same manner as above. Furthermore, a first buffer layer 31H is formed on the back surface of the heat-soothing layer 712H. Next, a heat-soothing layer 713H is formed on the back surface of the first buffer layer 31H. The method for forming these layers, the protective layer 60, and the heat-retaining resistor layer 40 is the same as the method for forming the first metal substrate laminate 4A, except for the formation of the heat-soothing layer 71, and drying and firing are performed using a high-temperature profile. As a result, the first metal substrate laminate 6A is formed.

[0041] To form the second metal substrate laminate 6B, a glass reinforcement layer 52H having through holes 73h, 74h, 75h, and 76h is laminated onto the surface of the second metal substrate 20. Furthermore, a second buffer layer 33H is formed on the surface of the glass reinforcement layer 52H. Next, a heat-soothing layer 714H is formed on the surface of the second buffer layer 33H. The method for forming these layers is the same as the method for forming the first metal substrate laminate 4A, except for the formation of the heat-soothing layer 71, and drying and firing are performed using a low-temperature profile. As a result, the second metal substrate laminate 6B is formed.

[0042] Then, as shown in Figure (c), conductive material is printed into the through holes 73h, 74h, 75h, and 76h formed in the first metal substrate laminate 6A and the second metal substrate laminate 6B, and then dried and fired to form conductive parts 73A, 74A, 75A, and 76A. This drying and firing is performed using a low-temperature profile. (2) Intermediate buffer layer formation and bonding process The intermediate buffer layer formation and bonding process is carried out according to the procedure shown in Figure 31(a). Specifically, as shown in Figure (b), intermediate buffer layer materials 32Ha and 32Hb are printed onto the back surface of the heat-saturating layer 713H and the front surface of the heat-saturating layer 714H, respectively, and then dried. Next, as shown in Figure (c), they are bonded (including lamination) and fired. Drying and firing are performed using a buffer profile. The metal heater 6 is then manufactured.

[0043] [3] Method for Manufacturing Metal Heater 82 As shown in Figure 12, the metal heater 82 is equipped with a solder layer 90 and metal layers 91, 91 instead of the buffer layer 30 in the metal heater 4. The following will mainly explain the differences from the method for manufacturing the metal heater 4. As shown in Figure 32, the method for manufacturing the metal heater 82 consists of a "first metal substrate laminate formation step", a "second metal substrate laminate formation step", and a "metal / solder layer formation and bonding step". (1) First Metal Substrate Laminate Formation Step The first metal substrate laminate formation step in the method for manufacturing the metal heater 82 consists of two steps: a "glass reinforcement layer / heating resistor layer formation step" and a "protective layer formation step", which are obtained by removing the "first buffer layer formation step" from the first metal substrate laminate formation step shown in Figure 21. In other words, the "glass reinforcement layer / heat-resistant layer formation process" and the "protective layer formation process" form a first metal substrate laminate 4a consisting of a first metal substrate 10, a heat-resistant layer 40, a protective layer 60, and a glass reinforcement layer 51 (see Figure 34(a)).

[0044] (2) Second Metal Substrate Laminate Formation Process The second metal substrate laminate formation process in the manufacturing method of the metal heater 82 consists only of the "glass reinforcement layer formation process," which is the second metal substrate laminate formation process shown in Figure 24 with the "second buffer layer formation process" removed. That is, the "glass reinforcement layer formation process" forms a second metal substrate laminate 4b consisting of a second metal substrate 20 and a glass reinforcement layer 52 (see Figure 34(b)). It is also possible to omit either the glass reinforcement layer 51 or the glass reinforcement layer 52, and if the glass reinforcement layer 52 is not provided, the second metal substrate laminate formation process will not be included.

[0045] (3) Metal and solder layer formation and joining process The metal and solder layer formation and joining process is a process of joining the first metal substrate laminate 4a produced in (1) and the second metal substrate laminate 4b produced in (2) via a solder layer 90 to form a metal heater 82.

[0046] (3-1) Metal and Solder Layer Formation and Joining Process Part 1 The metal and solder layer formation and joining process in the manufacturing method of the metal heater 82 consists of four steps, as shown in Figure 33: a first metal substrate metal layer formation step, a second metal substrate metal layer formation step, a solder layer lamination step, and a solder joining step.

[0047] The first metal substrate metal layer formation step is a step in which a metal layer 91 is laminated on the back side of the glass reinforcement layer 51 (first metal substrate laminate 4a) laminated on the first metal substrate 10 in order to make the bonding by the solder layer 90 more reliable. The metal layer 91 is formed by the procedure shown in the first metal substrate metal layer formation step in Figure 34(a). Specifically, a paste-like metal layer material is laminated on the back side of the glass reinforcement layer 51 laminated on the first metal plate layer 10, for example by screen printing. The metal layer material layer may be laminated using a method other than printing. Then, the metal layer 91 is formed by drying and firing using the high-temperature profile described above.

[0048] The second metal substrate metal layer formation process is a process of laminating a metal layer 91 on the front side of the glass reinforcement layer 52 (second metal substrate laminate 4b) laminated on the second metal substrate 20 in order to make the bonding by the solder layer 90 more reliable. The metal layer 91 is formed by the procedure shown in the second metal substrate metal layer formation process in Figure 34(b). Specifically, a paste-like metal layer material is laminated on the surface of the glass reinforcement layer 52 laminated on the second metal plate layer 20, for example by screen printing. The metal layer material layer may be laminated using a method other than printing. Then, the metal layer 91 is formed by drying and firing using the low-temperature profile described above. Furthermore, the second metal substrate metal layer formation process is not limited to the drying and firing procedure shown in Figure 34(b), and for example, the metal layer 91 may be formed by colliding metal particles at high speed using the AD method (aerosol deposition method).

[0049] The solder lamination process involves laminating solder pastes 90a and 90b onto metal layers 91, 91, and includes solder paste printing and drying steps, as shown in Figure 35(a). Specifically, as shown in Figure 35(b), solder paste 90a is printed onto the back surface of the first metal substrate laminate 4a on which the metal layers 91 are laminated, and then reflowed. Similarly, solder paste 90b is printed onto the surface of the second metal substrate laminate 4b on which the metal layers 91 are laminated, and then reflowed. Note that solder pastes 90a and 90b may be laminated using methods other than printing. There are no particular limitations on the reflow conditions, but it is preferable to heat at a temperature of 150 to 300°C under atmospheric conditions. The heating time is preferably 1 to 3 minutes.

[0050] The soldering process, as shown in Figure 35(a), includes bonding and drying steps. As shown in Figure 35(c), the reflowed solder paste 90a formed on the metal layer 91 on the first metal substrate laminate 4a side and the reflowed solder paste 90b formed on the metal layer 91 on the second metal substrate laminate 4b side are brought into close contact to form a solder layer laminate 82A having solder paste 90c. That is, the first metal substrate laminate 4a, on which the metal layer 91 is laminated, and the second metal substrate laminate 4b, on which the metal layer 91 is laminated, are joined together via the solder paste 90c. Next, the solder layer laminate 82A is placed in a reflow oven and heated, and then allowed to cool. At this time, the solder paste 90c melts and then cools and solidifies, thereby bonding the first metal substrate laminate 4a, on which the metal layer 91 is laminated, and the second metal substrate laminate 4b, on which the metal layer 91 is laminated. There are no particular limitations on the heating conditions, but it is preferable to heat at a temperature of 150 to 300°C under atmospheric conditions, and the heating time is preferably 1 to 3 minutes. As a result, the first metal substrate laminate 4a on which the metal layer 91 is laminated and the second metal substrate laminate 4b on which the metal layer 91 is laminated are firmly joined via the solder layer 90, and the metal heater 82 shown in Figure (d) is manufactured. In the case of the metal heaters 80 and 81 shown in Figures 10 and 11, similar to the manufacturing of the metal heater 82, metal layers 91, 91 may be laminated on the back side of the glass reinforcement layer 51 laminated on the first metal substrate 10 and the front side of the second metal substrate 20, or on the back side of the first metal substrate 10 and the front side of the glass reinforcement layer 52 laminated on the second metal substrate 20, respectively. Then, solder paste 90a, 90b may be printed onto the metal layers 91, 91 on the first metal substrate 10 side and the second metal substrate 20 side to form solder paste 90c, and then the first metal substrate 10 and the second metal substrate 20 may be joined together via the solder paste 90c to manufacture the metal heaters 80 and 81.

[0051] (3-2) Metal / Solder Layer Formation and Joining Process Part 2 In the manufacturing method of the metal heater 82, the metal / solder layer formation and joining process can also be carried out by following the steps of the solder layer lamination process and joining process shown in Figure 36, after the first metal substrate metal layer formation process and the second metal substrate metal layer formation process shown in Figure 34. Specifically, first, metal layers 91, 91 are formed by printing on the back side of the first metal substrate laminate 4a and the front side of the second metal substrate laminate 4b, respectively, by the first metal substrate metal layer formation process and the second metal substrate metal layer formation process, and then dried and fired using the high-temperature profile or low-temperature profile. Note that the metal layers 91 may be formed by methods other than printing. Next, in the solder lamination process, solder paste 90c is laminated by printing on the surface of the second metal substrate laminate 4b on which the metal layers 91 are laminated, and then reflowed. Note that the solder paste 90c may be laminated by methods other than printing. Furthermore, a soldering process is performed to bring the metal layer 91 on the first metal substrate laminate 4a side and the solder paste 90c formed on the second metal substrate laminate 4b side into close contact, thereby forming a solder layer laminate 82A having the solder paste 90c (see Figure 35(c)). Subsequently, the solder layer laminate 82A is heated in a reflow oven and then allowed to cool, thereby producing a metal heater 82 (see Figure 35(d)). In addition, in the case of the metal heaters 80 and 81 shown in Figures 10 and 11, similar to the manufacturing of the metal heater 82, metal layers 91, 91 may be laminated on the back side of the glass reinforcing layer 51 laminated on the first metal substrate 10 and the front side of the second metal substrate 20, or on the back side of the first metal substrate 10 and the front side of the glass reinforcing layer 52 laminated on the second metal substrate 20, respectively. Then, solder paste 90c may be printed onto the metal layer 91 on the second metal substrate 20 side, and then the first metal substrate 10 and the second metal substrate 20 may be joined together via the solder paste 90c to manufacture the metal heaters 80 and 81.

[0052] (3-3) Metal / Solder Layer Formation and Bonding Process Part 3 In addition, in the manufacturing method of the metal heater 82, the metal / solder layer formation and bonding process can also be carried out by following the procedures of the solder layer lamination process and bonding process shown in Figure 37 after the first metal substrate metal layer formation process and the second metal substrate metal layer formation process shown in Figure 34. Specifically, first, metal layers 91, 91 are formed by printing on the back side of the first metal substrate laminate 4a and the front side of the second metal substrate laminate 4b, respectively, by the first metal substrate metal layer formation process and the second metal substrate metal layer formation process, and then dried and fired using the high-temperature profile or low-temperature profile. Note that the metal layers 91 may be formed by methods other than printing. Next, in the solder lamination process, solder paste 90c is laminated by printing on the back side of the first metal substrate laminate 4a on which the metal layers 91 are laminated, and then reflowed. Note that the solder paste 90c may be laminated by methods other than printing. Furthermore, a soldering process is performed to bring the solder paste 90c formed on the metal layer 91 on the first metal substrate laminate 4a side and the metal layer 91 on the second metal substrate laminate 4b side into close contact, thereby forming a solder layer laminate 82A having the solder paste 90c (see Figure 35(c)). Subsequently, the solder layer laminate 82A is heated in a reflow oven and then allowed to cool, thereby producing a metal heater 82 (see Figure 35(d)). In addition, in the case of the metal heaters 80 and 81 shown in Figures 10 and 11, similar to the manufacturing of the metal heater 82, metal layers 91, 91 may be laminated on the back side of the glass reinforcing layer 51 laminated on the first metal substrate 10 and the front side of the second metal substrate 20, or on the back side of the first metal substrate 10 and the front side of the glass reinforcing layer 52 laminated on the second metal substrate 20, respectively. Then, solder paste 90c may be printed onto the metal layer 91 laminated on the first metal substrate 20 side, and then the first metal substrate 10 and the second metal substrate 20 may be joined together via the solder paste 90c to manufacture the metal heaters 80 and 81.

[0053] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be implemented in various modified forms.

[0054] In the metal heaters 1, 2, 3, 4, 5, and 6 according to the above-described embodiment, the second metal substrate 20 is disposed on the back surface of the first metal substrate 10 via a buffer layer 30. However, as shown in Figure 38, the metal heater 7 may be configured such that the second metal substrate 20 is disposed on the front surface of the first metal substrate 10, which has a heat-generating resistor layer 40 and a protective layer 60 laminated on it via a buffer layer 30. In this case, the metal heater 7 has a structure in which the first metal substrate 10, heat-generating resistor layer 40, protective layer 60, buffer layer 30, and first metal substrate 20 are laminated in that order from the back surface to the front surface. Alternatively, the second metal substrate 20 may be disposed on the front surface of the first metal substrate 10 via another glass layer as appropriate instead of the buffer layer 30, or the buffer layer 30 may be omitted. Furthermore, the protective layer 60 may be omitted.

[0055] Furthermore, in the metal heaters 80, 81, and 82 according to the above-described embodiment, the second metal substrate 20 is disposed on the back side of the first metal substrate 10 via a solder layer 90 and metal layers 91, 91. However, as shown in Figures 39 and 40, metal heaters 85 and 86 may be constructed in which the second metal substrate 20 is disposed on the front side of the first metal substrate 10, which has a heat-generating resistor layer 40 and a protective layer 60 laminated on it via a solder layer 90 and metal layers 91, 91. In this case, in the first metal substrate metal layer formation step in the metal / solder layer formation and bonding process, the metal layer 91 is formed on the front side of the protective layer 60. Note that metal heater 86 differs from metal heater 85 in that an insulating glass layer 52 is disposed on the back side of the second metal substrate 20.

[0056] Furthermore, although the metal heaters 80, 81, and 82 according to the above embodiment do not have a buffer layer 30, a configuration in which a buffer layer 30 is appropriately provided between the first metal substrate 10 and the second metal substrate 20 is also possible.

[0057] The metal heater of the present invention is industrially applicable in the fields of coolant heaters and battery heaters for electric vehicles.

[0058] 1, 2, 3, 4, 5, 6, 7, 80, 81, 82, 85, 86; Metal heater, 10; First metal substrate, 20; Second metal substrate, 30; Buffer layer, 31; First buffer layer, 32; Intermediate buffer layer, 33; Second buffer layer, 40; Heating resistor layer, 51, 52; Glass reinforcement layer, 71 (711, 712, 713, 714); Heating uniformity layer, 73h, 74h, 75h, 76h; Through hole, 90; Solder layer, 91; Metal layer, 92; Slit portion

Claims

1. A metal heater comprising: a first metal substrate; a heat-generating resistor layer laminated on the surface of the first metal substrate; a buffer layer laminated on the back surface of the first metal substrate; and a second metal substrate laminated on the back surface of the buffer layer and having a coefficient of thermal expansion greater than that of the first metal substrate.

2. The metal heater according to claim 1, wherein B is the coefficient of thermal expansion of the buffer layer and M2 is the coefficient of thermal expansion of the second metal substrate, and B < M2.

3. The metal heater according to claim 2, wherein M1 < B < M2 when the thermal expansion coefficient of the first metal substrate is M1.

4. The metal heater according to claim 1 or 2, wherein the material of the first metal substrate is stainless steel, and the material of the second metal substrate is aluminum or an aluminum alloy.

5. The metal heater according to claim 2, wherein the buffer layer comprises a first buffer layer laminated on the first metal substrate side, a second buffer layer laminated on the second metal substrate side, and an intermediate buffer layer laminated between the first buffer layer and the second buffer layer, and when the thermal expansion coefficient of the first buffer layer is B1, the thermal expansion coefficient of the intermediate buffer layer is B2, and the thermal expansion coefficient of the second buffer layer is B3, B1 < B2 < B3.

6. 9.1 x 10 －６ ( / °C) < B2 < 24.0 × 10 －６ The metal heater according to claim 5, wherein the temperature is ( / °C).

7. The metal heater according to claim 1, wherein a glass reinforcing layer is further laminated between the first metal substrate and the buffer layer and / or between the second metal substrate and the buffer layer.

8. The metal heater according to claim 1 or 7, wherein a heat-soothing layer having a higher thermal conductivity than the first metal substrate and the second metal substrate is further laminated at least one location between the laminated substrates and each layer.

9. The metal heater according to claim 8, wherein the buffer layer and / or the glass reinforcing layer, which are laminated adjacent to the heat-sensing layer, are provided with a plurality of through holes that penetrate from front to back, and the inside of the through holes is filled with a thermally conductive material.

10. The metal heater according to claim 1, wherein a solder layer is further laminated between the first metal substrate and the buffer layer, or between the second metal substrate and the buffer layer.

11. The metal heater according to claim 7, wherein a solder layer is further laminated between the first metal substrate and the glass reinforcing layer, between the second metal substrate and the glass reinforcing layer, or between the buffer layer and the glass reinforcing layer.

12. The metal heater according to claim 10 or 11, wherein a metal layer is laminated adjacent to the solder layer.

13. The metal heater according to claim 10 or 11, wherein the solder layer is stacked in a planar manner between each of the layers, and the solder layer has a slit portion cut out inward from the lateral outer edge.

14. The metal heater according to claim 1 or 2, further comprising a protective layer covering the heat-generating resistor layer.

15. The metal heater according to claim 1 or 2, wherein the heat-generating resistor layer comprises a heat-generating resistance wire formed on an insulating layer.

16. The metal heater according to claim 1 or 2, wherein the first metal substrate on which the heat-generating resistor layer is laminated and the second metal substrate are joined together via the buffer layer.

17. The metal heater according to claim 16, wherein the buffer layer is laminated on the back surface of the first metal substrate and / or on the surface of the second metal substrate, and then the first metal substrate on which the heating resistor layer is laminated and the second metal substrate are joined together.

18. The metal heater according to claim 10 or 11, wherein the first metal substrate on which the heat-generating resistor layer is laminated and the second metal substrate are joined via the solder layer.

19. The metal heater according to claim 12, wherein the metal layer is laminated on a layer adjacent to the solder layer, and then the first metal substrate on which the heating resistor layer is laminated and the second metal substrate are joined via the solder layer.

20. A metal heater comprising: a first metal substrate; a heat-generating resistor layer laminated on the surface of the first metal substrate; a buffer layer laminated on the surface of the heat-generating resistor layer; and a second metal substrate laminated on the surface of the buffer layer and having a coefficient of thermal expansion greater than that of the first metal substrate.

21. The metal heater according to claim 20, wherein a solder layer is further laminated between the second metal substrate and the buffer layer.

22. The metal heater according to claim 21, wherein a metal layer is laminated adjacent to the solder layer.

23. A method for manufacturing a metal heater comprising a first metal substrate, a second metal substrate having a coefficient of thermal expansion greater than that of the first metal substrate, and a buffer layer laminated between the first metal substrate and the second metal substrate, the method comprising: a step of laminating a heat-generating resistor layer on the surface of the first metal substrate; and a step of joining the back side of the first metal substrate on which the heat-generating resistor layer is laminated and the front side of the second metal substrate via the buffer layer.

24. The method for manufacturing a metal heater according to 23, characterized in that the buffer layer comprises a plurality of layers, and the buffer layer is placed on the back of the first metal substrate and / or on the front of the second metal substrate and joined together.

25. The method for manufacturing a metal heater according to claim 24, wherein the buffer layer is formed by heating a laminate including the unfired layer, and at least one of the multiple layers constituting the buffer layer is an unfired layer.

26. The method for manufacturing a metal heater according to claim 25, characterized in that the buffer layer comprises three layers, and the middle layer of the buffer layer in the front-back direction is unfired.

27. A method for manufacturing a metal heater comprising a first metal substrate, a second metal substrate having a coefficient of thermal expansion greater than that of the first metal substrate, and a buffer layer laminated between the first metal substrate and the second metal substrate, the method comprising: a step of laminating a heat-generating resistor layer on the surface of the first metal substrate; a step of laminating the buffer layer on the back surface of the first metal substrate on which the heat-generating resistor layer is laminated and / or on the surface of the second metal substrate; and a step of joining the first metal substrate and the second metal substrate via a solder layer between the buffer layer laminated on the back surface of the first metal substrate and the second metal substrate, between the buffer layer laminated on the surface of the second metal substrate and the first metal substrate, or between the buffer layer laminated on the back surface of the first metal substrate and the buffer layer laminated on the surface of the second metal substrate.

28. The metal heater according to claim 27, wherein the metal layer is laminated on a layer adjacent to the solder layer, and then the first metal substrate and the second metal substrate are joined via the solder layer.

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