A double layer thick film electric heater

Abstract

The application relates to the technical field of heaters, and discloses a double-layer thick-film electric heater. The double-layer thick-film electric heater comprises a flow channel base body, which comprises a base body shell, an interlayer partition plate, a plurality of upper layer flow channel plates, a plurality of lower layer flow channel plates, an upper layer fluid interface and a lower layer fluid interface; the interlayer partition plate divides a first cavity of the base body shell into an upper layer cavity and a lower layer cavity, the upper layer cavity is communicated with the upper layer fluid interface, the lower layer cavity is communicated with the lower layer fluid interface, and a through hole for communicating the upper layer cavity and the lower layer cavity is arranged on the interlayer partition plate; the plurality of upper layer flow channel plates are arranged in the upper layer cavity, and the plurality of lower layer flow channel plates are arranged in the lower layer cavity; an upper layer thick-film heating plate is matched with the base body shell, the interlayer partition plate and the upper layer flow channel plates to form an upper layer heating cavity; and a lower layer thick-film heating plate is matched with the base body shell, the interlayer partition plate and the lower layer flow channel plates to form a lower layer heating cavity. The application embodiment significantly improves the heat exchange power density and effectively reduces the overall volume under the same power requirement.

Description

Technical Field

[0001] This application relates to the field of heater technology, and more particularly to a double-layer thick film electric heater. Background Technology

[0002] Currently, the mainstream heating solutions used in water-cooled thermal management of new energy vehicles, liquid-cooled heating of energy storage batteries, and industrial instantaneous fluid heating equipment can be divided into the following two categories: (1) Single-layer thick film heater: Its overall structural layout is: aluminum cover → single-layer thick film heating plate → single die-cast water channel; that is, the water channel is attached to the single-layer thick film heating plate on one side, and the other side of the single-layer thick film heating plate is only equipped with a simple aluminum cover, which makes the heating plate exchange heat with the coolant on one side, and the heat is conducted on only one side.

[0003] (2) PTC ceramic electric heater: It is achieved by stacking multiple ceramic heating cores and adding heat dissipation aluminum fins on both sides. The whole adopts a side-pressing assembly structure, and the ceramic core is fixed by pressing the clamps on both sides. The coolant channel is set on the outside of the fins, and the heat exchange relies only on the indirect conduction of the fins. The whole machine must reserve space for pressing assembly on both sides. The side structure is thick, and the ceramic and fins are completely pressed and fixed laterally.

[0004] However, both types of heaters have drawbacks: Single-layer thick film heater: heat exchange is only on one side, and the upper limit of heat exchange power per unit area is low; if the heating power needs to be increased, it can only be achieved by widening and lengthening the water channel, which leads to a significant increase in the length and width of the whole machine and less than 50% utilization of internal space.

[0005] PTC ceramic electric heater: Due to the structural limitations of the ceramic body, the two-sided extrusion clamps and fins, the overall thickness and width redundancy is large, and the volume is more than 30% larger than that of a single-layer thick film heater under the same heating power; the side extrusion assembly is its inherent structural form, making it difficult to achieve a thin and light design.

[0006] Therefore, improvements to existing technologies are necessary.

[0007] The above information is provided as background information only to aid in understanding this application and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this application. Summary of the Invention

[0008] This application provides a double-layer thick film electric heater to solve the problem in the prior art that it is difficult to balance heating power and overall size.

[0009] To achieve the above objectives, this application provides the following technical solution: A double-layer thick-film electric heater, comprising: The flow channel substrate includes a substrate shell, a layer partition plate, multiple upper flow channel plates, multiple lower flow channel plates, an upper fluid interface, and a lower fluid interface. The layer partition plate is disposed within the substrate shell to divide the first cavity of the substrate shell into an upper cavity and a lower cavity along the thickness direction of the substrate. The upper cavity is connected to the upper fluid interface, and the lower cavity is connected to the lower fluid interface. A through hole is provided on the layer partition plate to connect the upper cavity and the lower cavity. Multiple upper flow channel plates are disposed within the upper cavity to form multiple upper flow channels, and multiple lower flow channel plates are disposed within the lower cavity to form multiple lower flow channels. An upper thick film heating plate is disposed in the upper cavity and cooperates with the base shell, the layer partition plate and the upper flow channel plate to form a sealed upper heating cavity; A lower thick film heating plate is disposed in the lower cavity and cooperates with the base shell, the layer spacer plate and the lower flow channel plate to form a sealed lower heating cavity; The control circuit board is electrically connected to the upper thick film heating plate and the lower thick film heating plate.

[0010] Optionally, in the upper heating cavity, a confluence cavity is formed between the two ends of each upper flow channel and the upper fluid interface and the through hole; in the lower heating cavity, a confluence cavity is formed between the two ends of each lower flow channel and the lower fluid interface and the through hole. At least a portion of the manifold is provided with multiple turbulence protrusions; the turbulence protrusions include turbulence ribs and / or columnar turbulence protrusions.

[0011] Optionally, the base shell of the flow channel substrate further provides a second cavity, which is arranged side by side with the first cavity along a direction perpendicular to the thickness direction of the base. The control circuit board is located in the second cavity, and the control circuit board is set at an angle to the upper thick film heating plate and the lower thick film heating plate.

[0012] Optionally, the double-layer thick film electric heater further includes a heater housing; The heater housing includes an independent upper cover, a lower cover, and a side cover, which are respectively installed on the upper cavity, the lower cavity, and the opening end of the second cavity of the flow channel base; Alternatively, the heater housing may be an integral housing that at least covers the upper cavity, the lower cavity, and the opening end of the second cavity of the flow channel substrate.

[0013] Optionally, a sealing buffer pad is filled between the heater housing and the flow channel substrate; the sealing buffer pad is an integral silicone pad, or it consists of a sealing ring and multiple independent silicone strips.

[0014] Optionally, the flow channel substrate is provided with annular heating plate mounting positions at the top of the upper heating cavity and the bottom of the lower heating cavity, respectively. The heating plate mounting position has a groove in the inner ring and a flat bonding surface in the outer ring. A sealing ring is provided in the groove. The upper thick film heating plate and the lower thick film heating plate are respectively bonded to the corresponding flat bonding surface.

[0015] Optionally, the base shell, the layer spacer, the upper flow channel plate, and the lower flow channel plate are integrally die-cast or laser-welded.

[0016] Optionally, the upper thick film heating plate and / or the lower thick film heating plate include: a substrate, and a bottom insulating layer, a conductor layer, a heating resistor layer and an encapsulating insulating layer sequentially stacked on the substrate.

[0017] Optionally, the control circuit board integrates two IGBT drive modules and two IGBT power switches. Each IGBT drive module drives and connects to a corresponding IGBT power switch, and the two IGBT power switches are respectively connected to the upper thick film heating plate and the lower thick film heating plate.

[0018] Optionally, the conductive terminals of each IGBT power switch are pressed against the electrodes of the upper thick-film heating plate and the lower thick-film heating plate respectively by IGBT pressure strips.

[0019] Compared with the prior art, this application has the following beneficial effects: Significantly improves heat exchange power density: It can be heated simultaneously through double-layer thick film heating plates, and the heating area per unit volume is increased many times over; With multiple parallel flow channels, the fluid obtains a longer heat exchange path and a larger heat exchange contact area in a limited space, and the heat exchange power per unit volume is greatly improved. Effectively reduces the overall size: Under the same power requirements, there is no need to widen or lengthen the water channel, the substrate plane size can be controlled within a small range, the overall size is significantly reduced, and it is suitable for lightweight and miniaturized assembly requirements; More uniform thermal stress distribution: The symmetrical arrangement of the double-layer heating plates makes the heat distribution of the base shell along the thickness direction more even, avoiding the large temperature difference and thermal stress concentration problems caused by single-sided heating in single-layer heating structures, which is conducive to improving the long-term reliability of the sealing structure.

[0020] This application has other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of this application. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is an assembly diagram of the double-layer thick film electric heater provided in the embodiments of this application; Figure 2 This is an exploded view of the double-layer thick film electric heater provided in the embodiments of this application; Figure 3 This is a cross-sectional view of the double-layer thick film electric heater provided in the embodiments of this application; Figure 4 This is a structural diagram of the upper heating cavity of the flow channel substrate provided in the embodiments of this application; Figure 5 This is a structural diagram of the lower heating cavity of the flow channel substrate provided in the embodiments of this application; Figure 6 This is an exploded view of the thick film heating plate provided in the embodiments of this application.

[0023] Figure label: 1. Substrate shell; 2. Layer partition plate; 3. Upper flow channel plate; 4. Lower flow channel plate; 5. Upper fluid interface; 6. Lower fluid interface; 7. Upper thick film heating plate; 8. Lower thick film heating plate; 9. Control circuit board; 10. Through hole; 11. Turbulence protrusion; 12. Top cover; 13. Bottom cover; 14. Side cover; 15. Low-voltage plug; 16. High-voltage plug; 17. Sealing buffer pad; 18. Sealing ring; 19. Screw; 20. IGBT pressure strip; 21. Substrate; 22. Bottom insulating layer; 23. Conductor layer; 24. Heating resistor layer; 25. Encapsulating insulating layer. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] The inventors discovered that existing single-layer thick-film heaters and PTC ceramic electric heaters both have various defects: (1) Low space utilization and large overall size: The single-layer thick film heater only arranges the water channel and heating layer on a single plane. To increase the heating power, it can only rely on widening and lengthening the water channel to achieve the lateral extension of the substrate; the PTC ceramic electric heater has a large redundancy in the thickness and width directions due to the structural limitations of the ceramic body, the extrusion plates on both sides and the fins. Both result in a large internal installation space occupied by the equipment, making it difficult to adapt to the assembly requirements of miniaturization and lightweighting.

[0026] (2) Low heat exchange efficiency and high energy consumption: In single-layer thick film heaters, the fluid only contacts the heating plate on one side once, resulting in a limited heat exchange contact area. When the fluid is in laminar flow, the heat transfer coefficient is low, and a large amount of heat cannot be quickly transferred to the coolant. In PTC ceramic electric heaters, the coolant flow channel is located on the outside of the fins, and heat exchange relies solely on indirect conduction through the fins, resulting in high thermal resistance. Both suffer from high residual heat loss, slow temperature rise rate at the same power, and high energy consumption.

[0027] (3) PTC assembly side extrusion is prone to structural deformation and poor product reliability: PTC ceramic electric heaters must press the heating core by side extruding the aluminum profile cavity. Uneven extrusion pressure can easily cause the shell to be side-depressed and deformed, resulting in increased heat conduction gap and even crushing PTC ceramics. The yield of finished products is low and the performance degrades significantly after long-term use.

[0028] (4) The single-layer heating structure has concentrated thermal stress and the seal is prone to failure: The single-layer thick film heater has a large temperature difference between the two sides of the substrate due to heating on one side, and the thermal expansion stress is concentrated. In addition, the single-layer silicone seal is prone to aging and cracking under long-term hot and cold cycles, which poses safety hazards such as water leakage and electric leakage.

[0029] Therefore, please refer to Figures 1 to 5 This application provides a double-layer thick-film electric heater, comprising: The flow channel substrate includes a substrate shell 1, a layer partition plate 2, multiple upper flow channel plates 3, multiple lower flow channel plates 4, an upper fluid interface 5, and a lower fluid interface 6. The layer partition plate 2 is disposed within the substrate shell 1 to divide the first cavity of the substrate shell 1 into an upper cavity and a lower cavity along the thickness direction of the substrate. The upper cavity is connected to the upper fluid interface 5, and the lower cavity is connected to the lower fluid interface 6. The layer partition plate 2 has a through hole 10 connecting the upper cavity and the lower cavity. Multiple upper flow channel plates 3 are disposed within the upper cavity to form multiple upper flow channels, and multiple lower flow channel plates 4 are disposed within the lower cavity to form multiple lower flow channels. The upper thick film heating plate 7 is located in the upper cavity and cooperates with the base shell 1, the layer partition plate 2 and the upper flow channel plate 3 to form a sealed upper heating cavity. The lower thick film heating plate 8 is located in the lower cavity and cooperates with the base shell 1, the layer partition plate 2 and the lower flow channel plate 4 to form a sealed lower heating cavity; The control circuit board 9 is electrically connected to the upper thick film heating plate 7 and the lower thick film heating plate 8.

[0030] During the operation of the aforementioned double-layer thick-film electric heater, the coolant can enter the upper cavity through the upper fluid interface 5, and then be distributed to multiple upper flow channels. In the upper heating cavity, it exchanges heat with the upper thick-film heating plate 7. Subsequently, it flows into the lower cavity through the through-holes 10 on the layer partition plate 2, and is distributed to multiple lower flow channels. In the lower heating cavity, it exchanges heat again with the lower thick-film heating plate 8. Finally, it flows out of the flow channel substrate through the lower fluid interface 6. Thus, the fluid flows sequentially through the upper and lower flow channels within the flow channel substrate, achieving continuous double-layer heating.

[0031] In general, this embodiment divides the first cavity of the flow channel substrate into upper and lower layers along the thickness direction using a partition plate 2 within the same flow channel substrate. Each layer contains an independent thick-film heating plate and multiple parallel flow channels, allowing the fluid to flow synchronously within both flow channels and exchange heat with the corresponding heating plates. This achieves parallel heating of two layers and multiple flow channels per unit volume. In other words, this embodiment does not rely on increasing the planar area of ​​the heating plates to improve power; instead, it utilizes the space along the thickness direction of the substrate to transform the original single-layer, single-sided heating into double-layer, double-sided heating, decoupling power increase from volume increase.

[0032] Specifically, the embodiments of this application have the following technical effects: Significantly improves heat exchange power density: It can be heated simultaneously through double-layer thick film heating plates, and the heating area per unit volume is increased many times over; With multiple parallel flow channels, the fluid obtains a longer heat exchange path and a larger heat exchange contact area in a limited space, and the heat exchange power per unit volume is greatly improved. Effectively reduces the overall size: Under the same power requirements, there is no need to widen or lengthen the water channel. The planar dimensions of the base shell 1 can be controlled within a small range, and the overall size is significantly reduced, which is suitable for lightweight and miniaturized assembly requirements. More uniform thermal stress distribution: The symmetrical arrangement of the double-layer heating plates makes the heat distribution of the base shell 1 more even along the thickness direction, avoiding the large temperature difference and thermal stress concentration problems caused by single-sided heating in single-layer heating structures, which is conducive to improving the long-term reliability of the sealing structure.

[0033] In one optional embodiment, in the upper heating cavity, a confluence cavity is formed between the two ends of each upper flow channel and the upper fluid interface 5 and the through hole 10; in the lower heating cavity, a confluence cavity is formed between the two ends of each lower flow channel and the lower fluid interface 6 and the through hole 10; at least some of the confluence cavities are provided with a plurality of turbulence protrusions 11.

[0034] For example, the turbulence protrusion 11 includes turbulence ribs and / or columnar turbulence protrusions.

[0035] This embodiment is based on the installation of turbulence protrusions 11 within the manifold. After the fluid enters the manifold from the interface, it does not flow smoothly and directly into each channel. Instead, under the obstruction and guidance of the turbulence protrusions 11, the flow direction changes, and the fluid particles collide and mix violently, breaking the original laminar flow state and forming a turbulent or mixed flow state. The turbulent fluid then flows into each parallel channel for heat exchange. The fluid flowing out of the channel outlet is again disturbed by the turbulence protrusions 11 in the manifold at the other end before being collected and discharged. In this way, not only is the heat transfer coefficient significantly improved, thus effectively increasing the heat transfer efficiency under the same conditions, but also the turbulent state allows for thorough mixing of hot and cold fluids, eliminating local temperature stratification and making the inlet temperature of each channel more uniform, thus improving temperature uniformity.

[0036] Please see Figure 3 The substrate shell 1 of the flow channel substrate is also provided with a second cavity, which is arranged in parallel with the first cavity along a direction perpendicular to the thickness direction of the substrate; the control circuit board 9 is disposed in the second cavity, and the control circuit board 9 is arranged at an angle (such as perpendicularly) with the upper thick film heating plate 7 and the lower thick film heating plate 8.

[0037] This embodiment achieves a spatial separation layout between the control circuit board 9 and the heating cavity. On the one hand, it can effectively reduce the overall length and width of the machine, making the structure more compact and improving the utilization rate of internal space. On the other hand, it can reduce the conduction and radiation of heat from the heating cavity to the circuit board, reduce the operating temperature of the circuit board, and improve the reliability of electrical components. At the same time, the circuit board and the heating plate are set up independently in separate cavities, and their disassembly and assembly do not interfere with each other, which facilitates later inspection and maintenance.

[0038] In one alternative implementation, please refer to Figure 2 and Figure 3 The double-layer thick film electric heater also includes a heater housing; the heater housing includes an independent upper cover 12, a lower cover 13 and a side cover 14, which are respectively covered on the upper cavity, the lower cavity and the opening end of the second cavity of the flow channel substrate.

[0039] A sealing buffer pad 17 is also filled between the heater housing and the flow channel substrate; the sealing buffer pad 17 is an integral silicone pad, or it is composed of a sealing ring 18 and multiple independent silicone strips, whichever is more specific.

[0040] Based on this, the upper cover 12 and the lower cover 13 are fixedly connected to the flow channel substrate by fasteners (such as screws 19) that are vertically locked along the thickness direction, so that the upper cover 12 and the lower cover 13 are vertically pressed against the corresponding opening end of the flow channel substrate from top to bottom or from bottom to top, respectively.

[0041] Understandably, unlike the assembly method of the traditional PTC heater with the side-extruded aluminum profile cavity, this embodiment adopts a vertical locking method. The fastener applies pressure along the thickness direction of the flow channel substrate. The pressure is uniformly and vertically applied between the cover and the flow channel substrate, only pressing the sealing buffer pad 17 and the sealing ring 18 to achieve a seal. It does not generate lateral extrusion force on the substrate shell 1 and the heating plate, thereby avoiding problems such as shell deformation, increased heat conduction gap or damage to the heating plate caused by uneven lateral extrusion. This effectively improves the product assembly yield and long-term reliability.

[0042] In one optional embodiment, the flow channel substrate is provided with annular heating plate mounting positions at the top of the upper heating cavity and the bottom of the lower heating cavity, respectively. The heating plate mounting positions have a groove in the inner ring and a flat bonding surface in the outer ring. A sealing ring 18 is provided in the groove, and the upper thick film heating plate 7 and the lower thick film heating plate 8 are respectively bonded to the corresponding flat bonding surfaces.

[0043] In this embodiment, an inner ring groove is provided on the flow channel substrate to accommodate the sealing ring 18 for sealing, and an outer ring flat contact surface is used to tightly fit with the edge of the heating plate to ensure the flatness of the installation. Thus, when the sealing ring 18 is compressed, it deforms into the inner ring space and will not overflow to the contact surface, affecting the flatness of the heating plate; at the same time, the annular groove forms a radial limit for the sealing ring 18, preventing it from shifting or creeping during long-term thermal cycling, maintaining stable compression, and thus improving long-term sealing reliability.

[0044] In another alternative implementation, the heater housing can be a one-piece, fully enclosed outer shell, with 19 screws vertically locking around the outer circumference, reducing the number of parts and simplifying the assembly process.

[0045] The heater housing can be made of aluminum or stainless steel to improve corrosion resistance.

[0046] It should be noted that the base shell 1, the layer partition plate 2, the upper flow channel plate 3 and the lower flow channel plate 4 are integrally die-cast, or they can be formed by laser welding and sealing, which reduces the cost of die-casting molds and is suitable for small-batch customization.

[0047] Please see Figure 6 The upper thick film heating plate 7 and / or the lower thick film heating plate 8 may include: a substrate 21, and a bottom insulating layer 22, a conductor layer 23, a heating resistance layer 24 and an encapsulating insulating layer 25 sequentially stacked on the substrate 21.

[0048] The substrate 21 is a stainless steel plate used to support the thin-film circuit and transfer heat. Alternatively, it can be an alumina ceramic substrate 21, which offers stronger insulation and is suitable for ultra-high voltage heating applications. The bottom insulating layer 22 is a ceramic-glass material layer that acts as an insulating medium between the heating resistor layer 24 and the stainless steel substrate 21 to ensure basic insulation. The conductor layer 23 is a silver, palladium, or platinum material layer used to connect the heating resistor and provide external power input solder joints. The heating resistor layer 24 is a precious metal material layer such as silver, palladium, or ruthenium, used for heating when electricity is applied. The encapsulating insulating layer 25 is a ceramic material layer used to protect the internal conductive circuitry from scratches or impacts. The bottom insulating layer 22, conductor layer 23, heating resistor layer 24, and encapsulating insulating layer 25 are sequentially co-sintered and fixed onto the substrate 21 at 850°C.

[0049] In addition, the control circuit board 9 integrates an IGBT drive module, an IGBT power switch, an NTC temperature sampling circuit, and an over-temperature / over-current protection circuit. The conductive terminals of the IGBT power switch are pressed against the electrodes of the upper thick film heating plate 7 and the lower thick film heating plate 8 respectively through the IGBT pressure strip 20.

[0050] In one optional implementation, the control circuit board 9 is configured with a dual-path independent drive structure, meaning that the control circuit board 9 has two IGBT drive modules and two IGBT power switches. The two IGBT power switches are respectively connected to the upper thick-film heating plate 7 and the lower thick-film heating plate 8, and the two IGBT drive modules drive the corresponding IGBT power switches. The NTC temperature sampling circuit collects the temperature of the upper heating cavity and the lower heating cavity in real time, and the over-temperature / over-current protection circuit cuts off the power supply to the corresponding heating plate when the temperature or current exceeds the threshold, realizing independent temperature control and protection for each zone.

[0051] Based on the above structure, the double-layer thick-film electric heater can flexibly adjust its working mode according to actual heating needs: under low-load conditions, only the upper thick-film heating plate 7 or the lower thick-film heating plate 8 can be controlled to operate, reducing energy consumption; under full-load conditions, both the upper thick-film heating plate 7 and the lower thick-film heating plate 8 can be controlled to operate simultaneously at full load, achieving maximum heating power output. Simultaneously, dual-path independent control allows different target temperatures to be set for the upper and lower layers, adapting to segmented variable-power heating scenarios, avoiding the risk of localized overheating or dry burning, while improving temperature control accuracy and safety.

[0052] In summary, the double-layer thick-film electric heater provided in this application, by separating the upper cavity and the lower cavity in the thickness direction of the flow channel substrate and accommodating independent thick-film heating plates and multiple parallel flow channels respectively, achieves double-layer, double-sided synchronous heat exchange, representing a significant technological advancement compared to existing single-layer thick-film and PTC solutions. Firstly, the dual upper and lower flow channels significantly improve space utilization and reduce the overall size of the machine: the upper and lower flow channels and double heating plates are integrated within the same thickness space, making full use of the vertical space. Under the same rated heating power, the overall planar size of the machine is reduced by more than 30%, the internal installation space occupied by the equipment is greatly reduced, and the lightweight advantage is significant.

[0053] Secondly, it eliminates lateral extrusion and prevents shell deformation failure: The vertical locking assembly eliminates lateral extrusion force, preventing lateral dents and twisting deformation of the flow channel matrix, matrix shell 1, and heating plate. This avoids problems such as increased heat conduction gaps and breakage of heating elements, improving the yield rate of finished products and ensuring stable long-term operation.

[0054] Third, double-layer double-sided heat exchange significantly improves heat exchange efficiency per unit area: double-layer double-sided heat exchange nearly doubles the effective heat exchange area. Combined with the flow channel turbulence structure, it transforms laminar flow into turbulent flow, significantly improving the heat transfer coefficient. Under the same power, the fluid temperature rise rate increases by 40%, and heat loss is reduced by 12%~18%, resulting in energy saving and consumption reduction.

[0055] Fourth, the dual-layer heating and balanced heat dissipation reduce thermal stress and extend the sealing life: the dual-layer synchronous heating ensures that both sides of the substrate are heated evenly, and the thermal expansion stress cancels each other out. Combined with the composite sealing structure of multiple silicone and sealing rings, the life of the sealed product is more than twice that of a single-layer thick film.

[0056] Fifth, the power adjustment is flexible and adaptable to multiple scenarios: the double-layer heating plate can work independently or synchronously. Under low load, only one layer operates, while under full load, both layers output synchronously, resulting in higher temperature control accuracy, no risk of local dry burning, and stronger safety and reliability.

[0057] Therefore, this application effectively balances heating power and overall size, achieving substantial breakthroughs in miniaturization, high energy efficiency, and high reliability.

[0058] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A double-layer thick-film electric heater, characterized in that, include: The flow channel substrate includes a substrate shell (1), a layer partition plate (2), multiple upper flow channel plates (3), multiple lower flow channel plates (4), an upper fluid interface (5), and a lower fluid interface (6); wherein, the layer partition plate (2) is disposed in the substrate shell (1) to divide the first cavity of the substrate shell (1) into an upper cavity and a lower cavity along the thickness direction of the substrate, the upper cavity is connected to the upper fluid interface (5), the lower cavity is connected to the lower fluid interface (6), and the layer partition plate (2) is provided with a through hole (10) connecting the upper cavity and the lower cavity; multiple upper flow channel plates (3) are disposed in the upper cavity to form multiple upper flow channels, and multiple lower flow channel plates (4) are disposed in the lower cavity to form multiple lower flow channels; The upper thick film heating plate (7) is disposed in the upper cavity and cooperates with the base shell (1), the layer partition plate (2) and the upper flow channel plate (3) to form a sealed upper heating cavity; The lower thick film heating plate (8) is disposed in the lower cavity and cooperates with the base shell (1), the layer partition plate (2) and the lower flow channel plate (4) to form a sealed lower heating cavity; The control circuit board (9) is electrically connected to the upper thick film heating plate (7) and the lower thick film heating plate (8).

2. The double-layer thick-film electric heater according to claim 1, characterized in that, In the upper heating chamber, a confluence cavity is formed between the two ends of each upper flow channel and the upper fluid interface (5) and the through hole (10); in the lower heating chamber, a confluence cavity is formed between the two ends of each lower flow channel and the lower fluid interface (6) and the through hole (10). At least a portion of the manifold is provided with a plurality of turbulence protrusions (11); the turbulence protrusions (11) include turbulence ribs and / or columnar turbulence protrusions.

3. The double-layer thick-film electric heater according to claim 2, characterized in that, The base shell (1) of the flow channel substrate is further provided with a second cavity, which is arranged side by side with the first cavity in a direction perpendicular to the thickness direction of the base; The control circuit board (9) is disposed in the second cavity, and the control circuit board (9) is arranged at an angle to the upper thick film heating plate (7) and the lower thick film heating plate (8).

4. The double-layer thick-film electric heater according to claim 3, characterized in that, The double-layer thick film electric heater also includes a heater housing; The heater housing includes an independent upper cover (12), a lower cover (13), and a side cover (14), which are respectively installed on the upper cavity, the lower cavity, and the opening end of the second cavity of the flow channel base; Alternatively, the heater housing may be an integral housing that at least covers the upper cavity, the lower cavity, and the opening end of the second cavity of the flow channel substrate.

5. The double-layer thick-film electric heater according to claim 4, characterized in that, A sealing buffer pad (17) is filled between the heater housing and the flow channel substrate; the sealing buffer pad (17) is an integral silicone pad, or it is composed of a sealing ring (18) and multiple independent silicone strips.

6. The double-layer thick-film electric heater according to claim 1, characterized in that, The flow channel substrate has annular heating plate mounting positions at the top of the upper heating cavity and the bottom of the lower heating cavity. The heating plate mounting positions have a groove in the inner ring and a flat bonding surface in the outer ring. A sealing ring (18) is provided in the groove. The upper thick film heating plate (7) and the lower thick film heating plate (8) are respectively bonded to the corresponding flat bonding surfaces.

7. The double-layer thick-film electric heater according to claim 3, characterized in that, The base shell (1), the layer partition plate (2), the upper flow channel plate (3) and the lower flow channel plate (4) are integrally die-cast or laser-welded.

8. The double-layer thick-film electric heater according to claim 1, characterized in that, The upper thick film heating plate (7) and / or the lower thick film heating plate (8) include: a substrate (21), and a bottom insulating layer (22), a conductor layer (23), a heating resistance layer (24) and an encapsulating insulating layer (25) sequentially stacked on the substrate (21).

9. The double-layer thick-film electric heater according to claim 1, characterized in that, The control circuit board (9) integrates two IGBT drive modules and two IGBT power switches. Each IGBT drive module drives and connects to one of the corresponding IGBT power switches. The two IGBT power switches are respectively connected to the upper thick film heating plate (7) and the lower thick film heating plate (8).

10. The double-layer thick-film electric heater according to claim 9, characterized in that, The conductive terminals of each IGBT power switch are pressed against the electrodes of the upper thick film heating plate (7) and the lower thick film heating plate (8) respectively by the IGBT pressure bar (20).

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