Compact liquid heater for vehicle

Abstract

The compact liquid heater for the vehicle is characterized in that a shell unit comprises a main shell and a lower cover, and the lower end portion of the peripheral vertical edge of the main shell and the upper end portion of the peripheral vertical edge of the lower cover are connected in a locking and bonding mode; one end of the terminal strip is electrically connected with the thick film heating part of the efficient heat exchange core body unit; the low-voltage connector and the high-voltage connector are fixedly arranged at the low-voltage connector mounting interface part and the high-voltage connector mounting interface part on the main shell respectively; the control unit and the efficient heat exchange core body unit are fixedly mounted on a control unit mounting interface part and an efficient heat exchange core body unit mounting interface part in the top surface of the main shell in an up-down overlapping manner; the water inlet pipe and the water outlet pipe respectively extend out of two through holes in the main shell; pins of the low-voltage connector and the high-voltage connector are respectively connected with pin holes of the low-voltage connector and the high-voltage connector on the PCB; the other end of the terminal strip is inserted into a terminal strip pin hole in the PCB; the two water temperature sensors are respectively inserted into the two water temperature sensor mounting holes in the flat pipe; and the IGBT is clamped and fixed between the main shell and the flat tube. The device is small in size, light in weight and good in sealing performance.

Description

Technical Field

[0001] The invention belongs to the technical field of new energy vehicles, and in particular relates to a compact vehicle liquid heater. Background Art

[0002] The automotive liquid heater is the core component of the thermal management system of new energy vehicles. Its main function is to heat the battery in winter. It can also serve as an auxiliary heat source to heat the passenger compartment. According to different heating principles, automotive liquid heaters can be divided into PTC ceramic heaters, resistance wire heaters, and heating film heaters.

[0003] In the prior art, the heating film heater has a simple structure, large size, heavy weight, and a sealing ring is generally used to seal the water channel structure and the shell, which poses a risk of leakage. In addition, the assembly process is complicated, resulting in high cost, which seriously restricts the development of heating film heaters.

[0004] SUMMARY OF THE INVENTION

[0005] In view of the deficiencies in the prior art, the present invention provides a compact vehicle liquid heater with compact structure, small size, light weight and good sealing performance.

[0006] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0007] A compact vehicle liquid heater comprises a housing unit, a high-efficiency heat exchange core unit, a terminal block, a control unit, a low-voltage connector, a high-voltage connector, and a grounding bolt;

[0008] The housing unit is composed of a main housing and a lower cover, the main housing and the lower cover match in shape, the main housing is composed of a top surface and peripheral vertical edges, and the lower cover is composed of a bottom surface and peripheral vertical edges; the lower end of the peripheral vertical edge of the main housing and the upper end of the peripheral vertical edge of the lower cover are locked and bonded by buckling, and a mounting cavity is formed inside the two;

[0009] A control unit mounting interface and a high-efficiency heat exchange core unit mounting interface are provided inside the top surface of the main shell, and a low-voltage connector mounting interface and a high-voltage connector mounting interface are provided outside the top surface of the main shell; and two through holes are provided opposite to each other on the top surface of the main shell;

[0010] The control unit is composed of a PCB board, a water temperature sensor and an IGBT; the water temperature sensor is integrated on the PCB board;

[0011] The high-efficiency heat exchange core unit is composed of a flat tube with a thick film heating structure printed on one side, two plugging covers, a water inlet pipe and a water outlet pipe; the two plugging covers are fixed to the two ends of the flat tube, and the water inlet pipe and the water outlet pipe are respectively fixed to the water pipe installation holes on the flat tube near the two ends, so that a connected water path is formed between the water inlet pipe, the inside of the flat tube and the water outlet pipe; one end of the terminal block is connected to the thick film heating part by reflow soldering;

[0012] The low-voltage connector and the high-voltage connector are fixedly installed at the low-voltage connector installation interface and the high-voltage connector installation interface on the main shell, respectively; the control unit and the high-efficiency heat exchange core unit are fixedly installed at the control unit installation interface and the high-efficiency heat exchange core unit installation interface on the top surface of the main shell in an up-down stacking manner; the thick film heating structure is located on the side away from the PCB board, and the water inlet pipe and the water outlet pipe extend upward through two through holes on the main shell, respectively forming a water inlet interface end and a water outlet interface end;

[0013] The pins of the low-voltage connector and the high-voltage connector are respectively connected to the pin holes of the low-voltage connector and the high-voltage connector on the PCB; the other end of the terminal row is inserted into the pin holes of the terminal row reserved on the PCB; the two water temperature sensors of the control unit are respectively inserted into the two reserved water temperature sensor mounting holes on one side of the flat tube close to the water inlet pipe and the water outlet pipe; the IGBT is clamped and fixed in the middle cavity formed by the main housing and the flat tube, and an insulating film is arranged between the main housing and the IGBT;

[0014] The grounding bolt is installed on the housing unit.

[0015] Moreover, the main shell is an integrated die-cast structure of aluminum alloy, and the lower cover is a plastic mold part or an aluminum sheet metal stamping part.

[0016] Moreover, a circle of sealing grooves is arranged on the outer vertical edge of the main shell, and a plurality of clamping grooves are evenly arranged along the direction of the sealing groove, and the clamping grooves are connected and arranged on the outside of the sealing groove; a ring edge is arranged at the upper end of the vertical edge of the lower cover to cooperate with the sealing groove on the upper shell, and a plurality of clamping claws that cooperate with the clamping groove are evenly and integrally formed on the outside of the ring edge; the ring edge on the lower cover is embedded in the sealing groove on the main shell, and the plurality of clamping claws on the lower cover are embedded one by one in the plurality of clamping grooves on the main shell, and the main shell and the lower cover are sealed, bonded and fixedly connected by means of sealant filled in the sealing groove and the clamping groove.

[0017] Moreover, the inner side surface of the upper ring edge of the lower cover adopts an outwardly inclined inclined surface with an angle of 3° to 10°.

[0018] Moreover, the thick film heating structure is composed of an insulating layer, a resistance conductor layer and a protective layer which are sequentially arranged inside and outside.

[0019] Moreover, the main structure of the flat tube is a structure formed by drawing an aluminum profile; the plugging cover and the water pipe are structures formed by stamping an aluminum alloy; two water pipe mounting holes are vertically arranged near the two ends of the top surface of the flat tube, one water pipe mounting hole is used to mount an inlet pipe, and the other water pipe mounting hole is used to mount an outlet pipe; a water flow groove is arranged along the width direction of the flat tube at the positions corresponding to the two water pipe mounting holes on the inner side of the top surface of the flat tube; plugging cover slots are arranged at both ends of the flat tube; a flat tube mounting extension ear is respectively arranged near the two ends on both sides of the flat tube body parallel to the center line connecting the two water pipe mounting holes, and a screw insertion hole is arranged on each flat tube mounting extension ear, forming a fixing hole for mounting the high-efficiency heat exchange unit on the outer shell; two sensor fixing extension ears are arranged between the two flat tube mounting extension ears on one side, and a water temperature sensor fixing hole is arranged on the sensor fixing extension ear.

[0020] Moreover, inner wings are integrally formed in the flat tube holes of the flat tubes.

[0021] Furthermore, two external ears are integrally formed on both sides of the housing unit, and screw holes are arranged on the external ears.

[0022] Moreover, an outwardly extending avoidance groove is arranged on the top surface of the main housing above the PCB board for avoiding electrical components on the PCB board.

[0023] The advantages and positive effects of the present invention are:

[0024] 1. The present invention prints a thick film heating structure on a flat tube, and stacks a high-efficiency heat exchange core unit and a control unit in an outer shell unit. The IGBT of the control unit is pressed tightly by the main shell and the high-efficiency heat exchange core unit. On the one hand, it has the advantages of compact structure, small size and light weight. Compared with products of the same specifications, it can reduce weight by about 30%; on the other hand, it realizes cooling of the IGBT, which better ensures the normal operation of the IGBT.

[0025] 2. The main shell and the lower cover of the present invention are connected by a new buckling and bonding method, which has a simple and reliable process, realizes the use of zero sealing ring, has good sealing performance and high reliability.

[0026] 3. The control unit, high-efficiency core unit, sensor and other components of the present invention are connected by a high-efficiency plug-in structure, which can save 80% of the use of fasteners and is safer and more reliable.

[0027] 4. Compared with heaters of the same specifications and models, the heater of the present invention has a simple structure, the types and quantities of parts can be reduced by about 60%, and the production cost is low.

[0028] 5. The heater of the present invention has a wide applicable voltage range and can be applied to voltage requirements of DC800V and above, and can match the power according to the customer's heating power requirements, up to 10kW and above. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the appearance of the present invention;

[0030] Figure 2 It is a three-dimensional exploded view of the present invention;

[0031] Figure 3 is an exploded view of the housing unit of the present invention;

[0032] Figure 4 This is a partial enlarged view of the clip-fitting parts of the two parts of the housing connection sheet of the present invention.

[0033] Figure 5 It is a three-dimensional exploded view of the high-efficiency heat exchange unit of the present invention;

[0034] Figure 6 It is a schematic structural diagram of a flat tube with thick film heating components printed on both sides of the present invention;

[0035] Figure 7 It is a schematic diagram of the inner fin structure in the flat tube of the present invention;

[0036] Figure 8 It is a schematic diagram of the water flow channel structure in the flat tube of the present invention;

[0037] Fig. 9 It is a schematic diagram of the thick film heating structure printed on the flat tube of the present invention;

[0038] Fig.10 It is a schematic diagram of the connection between the terminal block of the present invention and the printed thick film heating part;

[0039] Fig.11 It is a structural schematic diagram of the control unit of the present invention;

[0040] Fig.12 It is a schematic diagram of the installation structure of the control unit of the present invention;

[0041] Fig.13 This is a schematic diagram of the installation structure of the high-efficiency heat exchange core unit of the present invention;

[0042] Fig.14 is a cross-sectional view of the installation position of the IGBT of the present invention;

[0043] Fig.15 It is a schematic diagram of the installation position of the terminal block of the present invention;

[0044] Fig.16 It is a schematic diagram of the water channel of the present invention. DETAILED DESCRIPTION

[0045] The structure of the present invention is further described below with reference to the accompanying drawings and by way of examples. It should be noted that the present examples are descriptive rather than restrictive.

[0046] A compact automotive fluid heater, see Figure 1-Figure 16 The invention point is: it includes a housing unit 1, a high-efficiency heat exchange core unit 2, a terminal block 3, a control unit 4, a low-voltage connector 5, a high-voltage connector 6, a grounding bolt 7, a fastening screw 8, etc. Figure 1 and Figure 2 .

[0047] The housing unit is composed of a main housing 1.1 and a lower cover 1.2. The main housing is made of an integral die-cast aluminum alloy; the lower cover is made of a plastic mold or aluminum sheet metal stamping. The main housing is provided with an interface portion for connecting components such as a high-efficiency heat exchange unit, a control unit, a low-voltage connector, a high-voltage connector, and a grounding bolt. Specifically, the main housing adopts a nearly square housing, which is composed of a top surface and an outer vertical edge. A group of raised columns of equal height in the inner circle and a group of raised columns of equal height in the outer circle are provided in the top surface, and the height of the group of raised columns in the inner circle is lower than the height of the group of raised columns in the outer circle, and a threaded hole is provided on each raised column. The group of raised columns in the inner circle is used to support and install the PCB board of the control unit, and the group of raised columns in the outer circle is used to support and install the high-efficiency heat exchange unit. An outwardly extending avoidance groove is provided between the group of raised columns in the inner circle to avoid electrical components of the PCB board, such as inductors, capacitors, etc. Two through holes are arranged on the top surface of the outer shell at positions outside the inner circle group of raised columns and between the outer circle group of raised columns, which are used to install the inlet and outlet water pipes of the high-efficiency heat exchange unit. Two mounting platforms are arranged outside the top surface of the outer shell unit, and a wire hole is arranged in the middle of the mounting platform. One mounting platform is a high-voltage connector mounting platform, and the other mounting platform is a low-voltage connector mounting platform. The high-voltage connector and the low-voltage connector are fixedly installed at the two mounting platforms by screws on four sides.

[0048] A circle of sealing grooves is arranged on the outer vertical edge of the main shell, and a plurality of slots 1.3 are evenly arranged along the direction of the sealing grooves, and the slots are connected and arranged on the outside of the sealing grooves. The lower cover is a cover structure that matches the shape of the main shell, and the lower cover is formed by stamping a plastic mold part or aluminum sheet metal. It is composed of a bottom surface and an outer vertical edge, and a reinforcing rib is arranged inside the bottom surface. The reinforcing rib can be arranged in a criss-cross structure as shown in the attached drawings. A ring edge that cooperates with the sealing groove on the upper shell is arranged at the upper end of the vertical edge of the lower cover, and a plurality of claws 1.4 that cooperate with the slots are evenly and integrally formed on the outside of the ring edge. The inner side surface of the above-mentioned ring edge adopts an outwardly inclined inclined surface, and the angle a is in the range of 3° to 10°, and its function is to facilitate the press-fitting of the lower cover and the main shell.

[0049] When assembling the main shell and the upper cover, first fill 1.5% sealant into the sealing groove of the main shell, and then use the pressure tool to press the lower cover ring edge and claws into the sealing groove of the main shell. As the pressure is pressed down, the claws are embedded in the groove to form a tight fit. After the sealant is cured, the outer shell unit is sealed.

[0050] The high-efficiency heat exchange unit is the core component, which consists of a flat tube 2.1 with a thick film heating structure printed on one side, a plug cover 2.2, and a water pipe. The main structure of the flat tube is drawn from an aluminum profile, and is provided with water pipe installation holes, fixing holes, water temperature sensor fixing holes, water flow channel grooves, plug cover slots and other structures through machining. Specifically, the flat tube is a sheet structure as a whole, and two water pipe installation holes 2.1.2 are vertically arranged near the two ends of the top surface of the flat tube. One water pipe installation hole is installed with an inlet water pipe 2.3, and the other water pipe installation hole is installed with an outlet water pipe 2.4. A water flow groove 2.1.5 is arranged along the width direction of the flat tube at the position corresponding to the two water pipe installation holes on the inner side of the top surface of the flat tube, so that the water in the flat tube holes in the entire width direction of the flat tube can be converged into the corresponding position of the water pipe through the water flow channel. Plug cover slots 2.1.6 are arranged at both ends of the flat tube, which are used to install plug covers at both ends to achieve the blocking of the flat tube at both ends. On the flat tube body, a flat tube installation extension ear is provided on both sides parallel to the center line of the two water pipe installation holes, near both ends. A screw insertion hole is provided on each flat tube installation extension ear, forming a fixing hole for installing the high-efficiency heat exchange unit on the outer shell, namely the flat tube installation hole 2.1.1. Two sensor fixing extension ears are provided between the two flat tube installation extension ears on one side, and a water temperature sensor fixing hole 2.1.3 is provided on the sensor fixing extension ears. The plug cover 2.2 and the two water pipes are made of aluminum alloy and are formed by stamping. The thick film heating structure is composed of an insulating layer, a resistance conductor layer, and a protective layer arranged inside and outside in sequence, and is formed by multiple sintering and printing in the furnace. Fig. 9 and Fig.10 Remove the outermost protective layer.

[0051] The assembly method of the high-efficiency heat exchange unit is as follows: after the flat tube 2.1 is machined, it is first cleaned and dried, and then the thick film heating part 2.5 is printed. After completion, the plug cover 2.2 and the inlet and outlet pipes are laser welded to the reserved installation holes of the flat tube to form a high-efficiency heat exchange unit. It should be emphasized that in the present invention, the internal flow channel of the flat tube is arranged with an inner wing structure 2.1.4, and the heat exchange performance is improved by about 10% compared with the structure without the inner wing.

[0052] One end of the terminal block is connected to the thick film heating part of the high-efficiency heat exchange unit through reflow soldering, and finally a complete high-efficiency heat exchange unit structure is formed. The terminal block 3 is mainly used to electrically connect the high-efficiency heat exchange unit 2 with the control unit 4.

[0053] The control unit can adjust the heating power of the high-efficiency heat exchange unit 2 and realize various functions and protection of the heater. It is mainly composed of a PCB board 4.1, a water temperature sensor 4.2, and an IGBT 4.3. Among them, the PCB board 4.1 is arranged with multiple capacitors, resistors, inductors and control circuits, which mainly realize the connection and control functions. The water temperature sensor 4.2 is integrated on the PCB board 4.1, and its function is to monitor the inlet and outlet water temperatures and feed back to the PCB board 4.1. Compared with the existing single temperature sensor structure, it has a high degree of integration and does not need to be arranged and installed separately, which can save most of the space and the number of fasteners. IGBT 4.3 is fixed to the PCB board 4.1 through a pin structure, and its function is to control the heating power of the heater through the duty cycle.

[0054] In the present invention, in order to realize the convenient installation of the entire liquid heater in the car, two external ears are integrally formed on both sides of the housing unit, and screw holes are arranged on the external ears to realize the installation and fixation of the heater. The external ears are composed of external ears arranged on the main shell and external ears arranged on the lower cover.

[0055] The whole assembly process of the compact vehicle liquid heater of the present invention is as follows:

[0056] ① Fix the low-voltage connector 5 and the high-voltage connector 6 to the corresponding interface positions reserved in the main housing by fastening screws 8.

[0057] ② Invert the main housing with low-voltage connector and high-voltage connector installed, and then fix the control unit 4 to the corresponding interface position reserved in the main housing 1.1 by fastening screws 8. The low-voltage connector pin hole 5.1 and the high-voltage connector pin hole 6.1 are connected to the low-voltage connector pin and the high-voltage connector pin, respectively. After the connection is completed, weld and fix them. Fig.12 shown.

[0058] ③ After the installation of the control unit 4 is completed, fix the high-efficiency heat exchange unit 2 with the terminal block 3 welded to the corresponding interface position reserved in the main shell 1.1 by tightening the screws 8, so that the high-efficiency heat exchange unit is located above the control unit, and the thick film heating structure is located on the upper surface away from the control unit. The pins of the terminal block 3 adopt a fisheye pin structure and are inserted into the terminal block pin holes 4.1.1 reserved in the control unit 4. The pin structure does not need to be welded and fixed to meet the fixing requirements. At the same time, the water temperature sensor 4.2 on the control unit 4 is inserted into the water temperature sensor installation hole reserved in the high-efficiency heat exchange unit 2; the inlet and outlet water pipes are laser welded to the periphery of the main shell, and finally the installation of the high-efficiency heat exchange unit is completed. Figure 13-15 shown.

[0059] It should be emphasized that the middle cavity formed by the main housing 1.1 and the high-efficiency heat exchange unit 2 tightly fixes the IGBT4.3, wherein an insulating film is arranged between the main housing 1.1 and the IGBT4.3 to ensure the insulation withstand voltage requirement of the IGBT4.3. This structure can save the IGBT4.3 fixing bracket and fastening screws, and the liquid in the high-efficiency heat exchange unit 2 can also cool the IGBT4.3 to ensure the normal operation of the IGBT4.3; at the same time, the installation structure of the water temperature sensor 4.2 can also save the fixing bracket and fastening screws; the simultaneous installation and fixing of the IGBT4.3 and the water temperature sensor 4.2 can save half of the assembly cost, such as Fig.15 As shown, this structure is an original structure.

[0060] ④ After the high-efficiency heat exchange unit 2 is assembled, the process of buckling and sealing the lower cover 1.2 can be carried out.

[0061] ⑤ Finally, the grounding bolt 7 is fixed on the main shell 1.1, and the assembly of the entire heater is completed.

[0062] The water channel structure of the invention is completely isolated from the shell, and the water channel structure is completed by laser welding, which has high reliability; the main shell and the lower cover adopt a buckled sealant structure to achieve the application of 0 sealing rings, which is safer and more reliable than the existing sealing ring structure. At the same time, it adopts an efficient heat exchange flow channel structure, with a high degree of component integration, more compact, lighter weight, fewer types of parts, and simple and quick assembly.

[0063] The implementation case described in the present invention is applicable to the voltage range: high voltage DC: 200~840v, low voltage DC: 9~16V; the rated power range is 3000~10000W; it solves the problems of low power, complex structure and high cost of traditional heaters, and greatly reduces the product size, weight and cost.

[0064] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A compact vehicle liquid heater, characterized in that: Including housing unit, high-efficiency heat exchange core unit, terminal block, control unit, low-voltage connector, high-voltage connector, and grounding bolt; The housing unit is composed of a main housing and a lower cover, wherein the main housing is composed of a top surface and peripheral vertical edges, and the lower cover is composed of a bottom surface and peripheral vertical edges; the lower end of the peripheral vertical edge of the main housing and the upper end of the peripheral vertical edge of the lower cover are locked and bonded by buckling, and a mounting cavity is formed inside the two; A control unit mounting interface and a high-efficiency heat exchange core unit mounting interface are provided inside the top surface of the main shell, and a low-voltage connector mounting interface and a high-voltage connector mounting interface are provided outside the top surface of the main shell; and two through holes are provided opposite to each other on the top surface of the main shell; The control unit is composed of a PCB board, a water temperature sensor and an IGBT; the water temperature sensor is integrated on the PCB board; The high-efficiency heat exchange core unit is composed of a flat tube with a thick film heating structure printed on one side, two plugging covers, a water inlet pipe and a water outlet pipe; the two plugging covers are fixed to the two ends of the flat tube, and the water inlet pipe and the water outlet pipe are respectively fixed to the water pipe installation holes on the flat tube near the two ends, so that a connected water path is formed between the water inlet pipe, the inside of the flat tube and the water outlet pipe; one end of the terminal block is electrically connected to the thick film heating part; The low-voltage connector and the high-voltage connector are fixedly installed at the low-voltage connector installation interface and the high-voltage connector installation interface on the main shell, respectively; the control unit and the high-efficiency heat exchange core unit are fixedly installed at the control unit installation interface and the high-efficiency heat exchange core unit installation interface on the top surface of the main shell in an up-down stacking manner; the thick film heating structure is located on the side away from the PCB board, and the water inlet pipe and the water outlet pipe extend upward through two through holes on the main shell, respectively forming a water inlet interface end and a water outlet interface end; The pins of the low-voltage connector and the high-voltage connector are respectively connected to the pin holes of the low-voltage connector and the high-voltage connector on the PCB; the other end of the terminal row is inserted into the pin holes of the terminal row reserved on the PCB; the two water temperature sensors of the control unit are respectively inserted into the two reserved water temperature sensor mounting holes on one side of the flat tube close to the water inlet pipe and the water outlet pipe; the IGBT is clamped and fixed in the middle cavity formed by the main housing and the flat tube, and an insulating film is arranged between the main housing and the IGBT; The grounding bolt is installed on the housing unit.

2. The compact vehicle liquid heater according to claim 1, characterized in that: The main housing is an integrated aluminum alloy die-casting structure, and the lower cover is a plastic mold part or an aluminum sheet metal stamping part.

3. The compact vehicle liquid heater according to claim 1, characterized in that: A circle of sealing grooves is arranged on the outer vertical side of the main shell, and a plurality of clamping grooves are evenly arranged along the direction of the sealing groove, and the clamping grooves are connected and arranged on the outside of the sealing groove; a ring edge is arranged on the upper end of the vertical side of the lower cover to match the sealing groove on the upper shell, and a plurality of clamping claws that match the clamping grooves are evenly and integrally formed on the outside of the ring edge; the ring edge on the lower cover is embedded in the sealing groove on the main shell, and the plurality of clamping claws on the lower cover are embedded one by one in the plurality of clamping grooves on the main shell, and the main shell and the lower cover are sealed, bonded and fixedly connected by means of sealant filled in the sealing groove and the clamping groove.

4. The compact vehicle liquid heater according to claim 3, characterized in that: The inner side surface of the upper ring edge of the lower cover adopts an outwardly inclined bevel with an angle of 3° to 10°.

5. The compact vehicle liquid heater according to claim 1, characterized in that: The thick film heating structure is composed of an insulating layer, a resistance conductor layer and a protective layer which are sequentially arranged inside and outside.

6. The compact vehicle liquid heater according to claim 1, characterized in that: The main structure of the flat tube is a structure formed by drawing an aluminum profile; the plugging cover and the water pipe are structures formed by stamping an aluminum alloy; two water pipe mounting holes are vertically arranged near the two ends of the top surface of the flat tube, one water pipe mounting hole is used to mount an inlet water pipe, and the other water pipe mounting hole is used to mount an outlet water pipe; a water flow groove is arranged along the width direction of the flat tube at the position corresponding to the two water pipe mounting holes on the inner side of the top surface of the flat tube; plugging cover slots are arranged at both ends of the flat tube; a flat tube mounting extension ear is arranged on each of the two sides of the flat tube body parallel to the center line of the two water pipe mounting holes, and a screw insertion hole is arranged on each flat tube mounting extension ear, forming a fixing hole for mounting the high-efficiency heat exchange unit on the outer shell; two sensor fixing extension ears are arranged between the two flat tube mounting extension ears on one side, and a water temperature sensor fixing hole is arranged on the sensor fixing extension ear.

7. The compact vehicle liquid heater according to claim 1, characterized in that: Inner wing is integrally formed in the flat tube hole of the flat tube.

8. The compact vehicle liquid heater according to claim 1, characterized in that: Two external ears are integrally formed on both sides of the housing unit, and screw holes are arranged on the external ears.

9. The compact vehicle liquid heater according to claim 2, characterized in that: An outwardly extending avoidance groove is arranged on the top surface of the main shell body above the PCB board for avoiding electrical components on the PCB board.

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