Thick-film high-pressure liquid heater and multi-stage heating circuit

Abstract

The utility model belongs to the technical field of thick film heating new energy automobile thermal management systems, and particularly discloses a thick film high-pressure liquid heater and a multistage heating circuit, comprising a relay, N thick film heating pipes and N kick switches, where N is greater than or equal to 2; the kick switches are in one-to-one correspondence with the thick film heating pipes; the N thick film heating pipes are arranged in parallel, and the adjacent thick film heating pipes are communicated through U-shaped pipes to form coiled pipes; heating resistance wires of the N thick film heating pipes are connected in series with a contact of the relay and are connected to a high-voltage power supply; and the N kick switches are connected in series with a coil of the relay after being connected and are connected to a low-voltage power supply. According to the utility model, the plurality of thick film heating pipes are connected in series, and the working voltage of the thick film heating body is effectively reduced and the reliability of the thick film heating pipes is improved by utilizing the series voltage division principle; the low-voltage direct-current power supply is adopted to directly supply power to the kick switch, and is independent of a high-voltage power supply path of the thick-film heating pipe, so that safe and reliable over-temperature control is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of thick-film heating thermal management systems for new energy vehicles, and in particular to a thick-film high-voltage liquid heater and a multi-stage heating circuit. Background Art

[0002] With the continuous advancement of technology, the voltage of new energy vehicle platforms continues to increase, and the penetration rate of high-voltage platforms is increasing. At the same time, the continuous increase in intelligent functions and the improvement of the user experience are also placing higher and higher demands on the thermal management of new energy vehicles. Heating is an essential and important part of the thermal management system. In low-temperature environments, heating performance directly affects driving range and comfort. Currently, the main heating method for new energy vehicles is PTC heating. PTC heating heats up quickly, is low-cost, and can automatically maintain a constant temperature without the need for additional temperature control devices. Thick-film heating has the advantages of small size, high power density, low attenuation, fast heating, and low starting current. Especially with the trend of high-voltage platforms and integrated thermal management systems, thick-film heating has significant advantages. However, thick-film heating devices must be equipped with temperature control and overheat protection circuits to prevent thermal runaway.

[0003] Currently, most high-voltage thick-film liquid heaters on the market use flat plate-shaped thick-film heating. These thick-film heating plates are subject to expansion and deformation during heating, and are at high risk of failure due to prolonged hot and cold cycling. Furthermore, as the voltage of new energy vehicle platforms continues to increase, and the penetration rate of 800-volt platforms continues to rise, the parameter requirements for thick-film heating elements are also becoming increasingly stringent. Furthermore, flat-plate thick-film heating uses a liquid cavity as a channel for liquid heat exchange, and the liquid needs to flow under a certain pressure, which places high demands on the liquid cavity or heater housing.

[0004] In industries like home appliances, kick switches are a widely used and mature solution for overheat protection, often connected in series with heating resistors in AC lines. However, in DC power supply environments like those used in new energy vehicles, where platform DC voltages are increasing, kick switches require a higher rated voltage. Furthermore, high-voltage DC power supplies can easily cause arcing in the kick switch contacts, leading to switch failure and potentially safety risks. Utility Model Content

[0005] The purpose of the utility model is to solve the technical problems existing in the background technology, and to this end, provides a thick film high-voltage liquid heater and a multi-stage heating circuit.

[0006] In order to achieve the above purpose, the technical solutions adopted by this utility model are as follows:

[0007] A thick film high-pressure liquid heater comprises a relay and N thick film heating tubes, wherein N ≥ 2;

[0008] N thick film heating tubes are arranged in parallel and adjacent thick film heating tubes are connected by U-shaped tubes to form a serpentine tube;

[0009] The thick film heating tube includes a heating resistance wire arranged in a thick film, and the heating resistance wires of N thick film heating tubes are connected in series with the contacts of the relay and are connected to a high voltage power supply.

[0010] The following is a further technical solution of the heater in the present invention, further comprising N kick switches, wherein the kick switches correspond one to one with the thick film heaters and are fixedly mounted on the outer wall of the thick film heating tube;

[0011] N kick switches are connected in series with the coil of the relay and then connected to a low-voltage power supply.

[0012] The following is a technical solution further limited to the heater in the present invention, wherein the kick switch is a normally closed kick switch, N kick switches are connected in series with the coil of the relay in sequence and connected to a low-voltage power supply, and the heating resistance wires of N thick-film heating tubes are connected in series with the normally open contacts of the relay and connected to a high-voltage power supply.

[0013] The following is a further technical solution of the heater in the present invention. The kick switch is a normally open kick switch. N kick switches are connected in parallel and then in series with the coil of the relay and connected to a low-voltage power supply. The heating resistance wires of N thick-film heating tubes are connected in series with the normally closed contacts of the relay and connected to a high-voltage power supply.

[0014] The following is a further technical solution of the heater in the present invention: stainless steel brackets are fixedly installed at both ends of the thick film heating tube, and the stainless steel brackets are installed inside the heater shell by screws. The thick film heating tube and the U-shaped tube are inside the heater shell.

[0015] The following is a further technical solution of the heater in the present invention: the heater housing is fixed with a water inlet pipe and a water outlet pipe, the water inlet pipe is connected to the input end of the serpentine pipe, and the water outlet pipe is connected to the output end of the serpentine pipe.

[0016] The following is a further technical solution of the heater in the present invention, wherein the sudden jump switch is a sudden jump temperature switch, the high voltage power supply is a high voltage DC power supply, and the low voltage power supply is a low voltage DC power supply.

[0017] A multi-stage heating circuit based on the thick film high-voltage liquid heater comprises a relay, N heating resistors and N kick switches, wherein N ≥ 2;

[0018] The sudden jump switches correspond to the heating resistors one by one;

[0019] N heating resistors are connected in series with the contacts of the relay and connected to a high-voltage power supply;

[0020] N kick switches are connected in series with the coil of the relay and then connected to a low-voltage power supply.

[0021] The following is a technical solution further defined by the circuit in the present invention, wherein the kick switch is a normally closed kick switch, N kick switches are connected in series with the coil of the relay in sequence and connected to a low-voltage power supply, and N heating resistors are connected in series with the normally open contacts of the relay and connected to a high-voltage power supply.

[0022] The following is a technical solution further defined by the circuit in the present invention, wherein the kick switch is a normally open kick switch, N kick switches are connected in parallel and then in series with the coil of the relay and connected to a low-voltage power supply, and N heating resistors are connected in series with the normally closed contacts of the relay and connected to a high-voltage power supply.

[0023] Compared with the prior art, the present invention has the following technical effects:

[0024] This utility model utilizes multiple thick-film heating tubes connected in series, leveraging the principle of series voltage division to effectively reduce the operating voltage of the thick-film heating element and improve its reliability. Furthermore, the mature technology of circular tubes capable of withstanding a certain pressure allows liquid under pressure to flow only through the series-connected circular tubes, simplifying the structure and reducing the thickness of the shell, thereby significantly reducing the overall weight of the heater. Furthermore, the circular tubes (thick-film heating tubes and U-shaped tubes) do not require complex flow path design relative to the liquid cavity or shell, and offer less flow resistance, thereby reducing water pump power and achieving energy savings.

[0025] The utility model adopts a low-voltage DC power supply to directly power the kick switch, which is independent of the high-voltage power supply path of the thick-film heating tube, thereby realizing safe and reliable over-temperature control.

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a circuit connection diagram of Example 1 of the present utility model;

[0029] Figure 2 This is a circuit connection diagram of Example 2 of the present utility model;

[0030] Figure 3 This is a simplified schematic diagram of the heater structure of the present utility model;

[0031] Figure 4 This is a simplified schematic diagram of the heater structure of Example 1 of the present utility model;

[0032] Figure 5 This is a simplified schematic diagram of the heater structure of Example 2 of the present utility model;

[0033] Figure 6 It is a structural schematic diagram of the substrate layer, ceramic insulation layer, heating layer, conductive circuit layer and encapsulation layer of the medium-thick film heating tube of the present invention. DETAILED DESCRIPTION

[0034] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of specific embodiments of the present invention is provided in conjunction with the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Example

[0035] like Figure 1 、 3 As shown in FIG4 , this embodiment provides a multi-stage heating circuit and a thick film high-voltage liquid heater.

[0036] like Figure 3 As shown, a thick film high pressure liquid heater consists of a heater housing B, a water inlet pipe C, a water outlet pipe D, 4 thick film heating tubes, 4 sudden trip switches, and a relay KJ ( Figure 3 Not shown), stainless steel bracket E, U-shaped tube F, high voltage power supply ( Figure 3 Not shown), low voltage power supply ( Figure 3 Among them, the water inlet pipe C and the water outlet pipe D are arranged on the side wall of the heater housing B for communicating with the inside and outside of the heater housing B; other structures are located inside the heater housing B. It should be noted that, Figure 3 This is a simplified structural diagram of the present invention, not a schematic structural diagram of an actual product, and is only used to help those skilled in the art understand the technical solution of the present invention.

[0037] The four thick film heating tubes are thick film heating tube one A1, thick film heating tube two A2, thick film heating tube three A3 and thick film heating tube four A4.

[0038] The four snap switches are snap switch KSD1, snap switch KSD2, snap switch KSD3 and snap switch KSD4. All four snap switches are snap-type temperature switches.

[0039] The sudden trip switch KSD1 is fixedly mounted on the outer wall of the thick film heating tube A1, the sudden trip switch KSD2 is fixedly mounted on the outer wall of the thick film heating tube A2, the sudden trip switch KSD3 is fixedly mounted on the outer wall of the thick film heating tube A3, and the sudden trip switch KSD4 is fixedly mounted on the outer wall of the thick film heating tube A4.

[0040] Stainless steel brackets are fixed at both ends of thick film heating tubes A1, A2, A3, and A4, with each tube positioned parallel to the other. Stainless steel bracket E is screwed into heater housing B.

[0041] In order to achieve the connection between the four thick film heating tubes, the U-shaped tube F is used to connect them to form a serpentine tube: Figure 3 and 4 As shown, the right end of thick-film heating tube A1 and the right end of thick-film heating tube A2 are flange-connected via a U-shaped tube F, sealed with a sealing ring. The left end of thick-film heating tube A2 and the left end of thick-film heating tube A3 are flange-connected via a U-shaped tube F, sealed with a sealing ring. The right end of thick-film heating tube A3 and the right end of thick-film heating tube A4 are flange-connected via a U-shaped tube F, sealed with a sealing ring. Therefore, the left end of thick-film heating tube A1 is flange-connected to the right end of water inlet pipe C, sealed with a sealing ring, and the left end of water inlet pipe C is located outside of heater housing B. The left end of thick-film heating tube A4 is flange-connected to the right end of water outlet pipe D, sealed with a sealing ring, and the left end of water outlet pipe D is located outside of heater housing B. Liquid flows from thick-film heating tube A1 into thick-film heating tube A4 and out, resulting in step-by-step heating.

[0042] It should be noted that welding between the thick film heating tube and the U-shaped tube also falls within the protection scope of the present utility model.

[0043] Thick film heating tube is an existing technology, namely: Figure 6 As shown, the thick film heating tube includes a substrate layer A01, a ceramic insulation layer A02, a heating layer A03, a conductive circuit layer A04 and an encapsulation layer A05 arranged in sequence from the inside to the outside. Among them, the heating layer A03 is composed of a heating resistance wire.

[0044] like Figure 4As shown, thick film heating tube 1 A1 includes a thick film heating resistor Rh1, thick film heating tube 2 A2 includes a thick film heating resistor Rh2, thick film heating tube 3 A3 includes a thick film heating resistor Rh3, and thick film heating tube 4 A4 includes a thick film heating resistor Rh4. The heating power of heating resistors Rh1, Rh2, Rh3, and Rh4 is the same.

[0045] The heating resistor wire Rh1, the heating resistor wire Rh2, the heating resistor wire Rh3, and the heating resistor wire Rh4 are sequentially connected in series and connected in series with the normally open contact of the relay KJ, and then connected to a high-voltage DC power supply (800V), thereby forming a power supply circuit.

[0046] The four kick switches are all normally closed kick switches: kick switch KSD1, kick switch KSD2, kick switch KSD3 and kick switch KSD4 are connected in series in sequence, and then connected in series with the coil of relay KJ, and then connected to a low-voltage DC power supply (12V or 24V) to form a power supply circuit.

[0047] It should be noted that the relay KJ in Example 1 is a normally open high-voltage DC relay.

[0048] like Figure 1 As shown, a multi-stage heating circuit consists of a relay KJ, heating resistors Rh1, Rh2, Rh3, and Rh4, kick switches KSD1, KSD2, KSD3, and KSD4, a high-voltage DC power supply, and a low-voltage DC power supply. The heating resistors Rh1, Rh2, Rh3, and Rh4 are connected in series, connected in series with the normally open contacts of relay KJ, and then connected to the high-voltage DC power supply, forming a power supply circuit. The kick switches KSD1, KSD2, KSD3, and KSD4 are all normally closed kick switches. They are connected in series, connected in series with the coil of relay KJ, and then connected to a low-voltage DC power supply (12V or 24V), forming a power supply circuit.

[0049] When the temperature of any thick film heating tube reaches the rated operating temperature of the normally closed snap switch, the snap switch is disconnected, and the power supply to the DC high voltage relay KJ coil is stopped. The normally open contact of the DC high voltage relay KJ is disconnected, thereby disconnecting the power supply circuit of the thick film heating tube and the thick film heating tube stops heating.

[0050] When the temperature of all thick film heating tubes drops to the closing temperature of the normally closed kick switch, all kick switches are closed, the DC high voltage relay KJ coil is energized, the normally open contacts of the DC high voltage relay KJ are closed, thereby closing the power supply circuit of the thick film heating tube and the thick film heating tube starts to heat up. Example

[0051] like Figure 2 、 3 As shown in Figure 5, based on the structure of Example 1, other structures remain unchanged, and the types of the four kick switches are changed, that is, all four kick switches are normally open kick switches. Then, the kick switch KSD1, the kick switch KSD2, the kick switch KSD3 and the kick switch KSD4 are connected in parallel in sequence, and then connected in series with the coil of the relay KJ, and then connected to a low-voltage DC power supply (12V or 24V) to form a loop.

[0052] It should be noted that the relay KJ in Example 2 is a normally closed high-voltage DC relay.

[0053] When the temperature of any thick film heating tube reaches the rated operating temperature of the normally open kick switch, the kick switch closes, the DC high voltage relay KJ coil is energized, and the DC high voltage relay KJ normally closed contact is disconnected, thereby disconnecting the thick film heating tube power supply circuit and the thick film heating tube stops heating.

[0054] When the temperature of all thick film heating tubes drops to the closing temperature of the normally closed kick switch, all kick switches are disconnected, and the power supply to the DC high voltage relay KJ coil is stopped. The normally closed contact of the DC high voltage relay KJ is closed, thereby closing the power supply circuit of the thick film heating tube and the thick film heating tube starts to heat up.

[0055] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any person skilled in the art can, without departing from the scope of the present invention, utilize the methods and technical content disclosed above to make many possible variations and modifications to the present invention, or modify it into equivalent embodiments with equivalent variations. Therefore, any equivalent variations based on the shape, structure, and principle of the present invention that do not depart from the content of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A thick film high pressure liquid heater, characterized in that: It includes a relay and N thick film heating tubes, wherein N is greater than or equal to 2; N thick film heating tubes are arranged in parallel and adjacent thick film heating tubes are connected by U-shaped tubes to form a serpentine tube; The thick film heating tube includes a heating resistance wire arranged in a thick film, and the heating resistance wires of N thick film heating tubes are connected in series with the contacts of the relay and are connected to a high voltage power supply.

2. A thick film high pressure liquid heater according to claim 1, characterized in that: It also includes N kick switches, each of which corresponds to a thick film heater and is fixedly mounted on an outer side wall of the thick film heating tube; N kick switches are connected in series with the coil of the relay and then connected to a low-voltage power supply.

3. A thick film high pressure liquid heater according to claim 2, characterized in that: The snap switches are normally closed snap switches, N snap switches are connected in series with the coils of the relay and connected to a low-voltage power supply, and the heating resistance wires of the N thick-film heating tubes are connected in series with the normally open contacts of the relay and connected to a high-voltage power supply.

4. A thick film high pressure liquid heater according to claim 2, characterized in that: The snap switch is a normally open snap switch. N snap switches are connected in parallel and then in series with the coil of the relay and connected to a low-voltage power supply. The heating resistance wires of N thick-film heating tubes are connected in series with the normally closed contacts of the relay and connected to a high-voltage power supply.

5. A thick film high pressure liquid heater according to claim 1, characterized in that: Stainless steel brackets are fixedly installed at both ends of the thick film heating tube, and the stainless steel brackets are installed inside the heater shell by screws. The thick film heating tube and the U-shaped tube are inside the heater shell.

6. A thick film high pressure liquid heater according to claim 5, characterized in that: The heater housing is fixedly provided with a water inlet pipe and a water outlet pipe, the water inlet pipe is connected to the input end of the serpentine pipe, and the water outlet pipe is connected to the output end of the serpentine pipe.

7. A thick film high pressure liquid heater according to claim 2, characterized in that: The snap switch is a snap temperature switch, the high-voltage power supply is a high-voltage direct current power supply, and the low-voltage power supply is a low-voltage direct current power supply.

8. A multi-stage heating circuit based on the thick film high-voltage liquid heater according to any one of claims 1 to 7, characterized in that: It includes a relay, N heating resistors and N snap switches, where N is greater than or equal to 2; The sudden jump switches correspond to the heating resistors one by one; N heating resistors are connected in series with the contacts of the relay and connected to a high-voltage power supply; N kick switches are connected in series with the coil of the relay and then connected to a low-voltage power supply.

9. The multi-stage heating circuit according to claim 8, characterized in that: The snap switches are normally closed snap switches, N snap switches are sequentially connected in series with the coils of the relay and connected to a low-voltage power supply, and N heating resistors are connected in series with the normally open contacts of the relay and connected to a high-voltage power supply.

10. The multi-stage heating circuit according to claim 8, wherein: The snap switches are normally open snap switches. N snap switches are connected in parallel and then in series with the coil of the relay and connected to a low-voltage power supply. N heating resistors are connected in series with the normally closed contacts of the relay and connected to a high-voltage power supply.

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