PTC heater assembly

Abstract

A PTC heater assembly (100), the PTC heater assembly (100) comprising a PTC heating unit (30) and a liquid flow heat exchange unit (20) thermally coupled with the PTC heating unit (30). The liquid flow heat exchange unit (20) comprises an upper liquid flow plate (21) and a lower liquid flow plate (22), an upper liquid flow channel (210) being formed in the upper liquid flow plate (21), and a lower liquid flow channel (220) being formed in the lower liquid flow plate (22). The PTC heating unit (30) comprises a PTC heating disc (31) clamped between the upper liquid flow plate (21) and the lower liquid flow plate (22), and the heating surfaces of the PTC heating disc (31) on two sides respectively transfer heat energy to the upper liquid flow plate (21) and the lower liquid flow plate (22) correspondingly, so as to heat the liquid within the upper fluid flow channel (210) and the lower fluid flow channel (220). The PTC heater assembly can reduce the occupied space and reduce the manufacturing difficulty.

Description

A PTC heater assembly

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on April 25, 2024, with application number 202420879565.0 and entitled “A PTC heater assembly”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of thermal management technology, and in particular to a PTC heater assembly. Background Technology

[0004] PTC (Positive Temperature Coefficient) heaters are used in fields such as new energy vehicles and are an important component of the thermal management system of new energy vehicles. Currently, PTC heaters in the industry typically achieve heat exchange through water-heat circulation. The heat exchange structures of PTC heaters are usually cast aluminum or water tank types. To achieve higher heating power, existing PTC heaters typically include a large number of heating elements. This results in numerous electrode pins on the heating elements, making direct soldering difficult and requiring a junction box. This makes the PTC heater complex, increases cost, and occupies a large space. Furthermore, the thickness of existing cast aluminum and water tank structures is usually relatively large, further increasing the overall height of the PTC heater and its space requirement, making it unsuitable for applications in confined spaces.

[0005] Therefore, it is necessary to propose a new technical solution to overcome the shortcomings of existing technologies.

[0006] Summary of the Invention

[0007] Based on this, this application provides a PTC heater assembly that can reduce the space occupied by the PTC heater assembly and reduce the manufacturing difficulty.

[0008] Therefore, this application adopts the following technical solution: a PTC heater assembly, including a PTC heating unit and a liquid flow heat exchange unit that is thermally connected with the PTC heating unit, wherein the liquid flow heat exchange unit includes an upper liquid flow plate and a lower liquid flow plate, an upper liquid flow channel is formed in the upper liquid flow plate, and a lower liquid flow channel is formed in the lower liquid flow plate. The PTC heating unit includes a PTC heating element sandwiched between the upper liquid flow plate and the lower liquid flow plate, and the heating surfaces on both sides of the PTC heating element respectively transfer heat to the upper liquid flow plate and the lower liquid flow plate to heat the liquid in the upper liquid flow channel and the lower liquid flow channel.

[0009] In one embodiment, the upper flow plate and the lower flow plate each include a substrate with a tortuous flow channel, fins disposed in the tortuous flow channel, and a cover plate sealing the substrate.

[0010] In one embodiment, an insulating film is provided between the upper and lower liquid flow plates and the PTC heating element.

[0011] In one embodiment, the upper liquid flow plate is provided with a first liquid inlet and a first liquid outlet, and the lower liquid flow plate is provided with a second liquid inlet and a second liquid outlet. The first liquid inlet and the first liquid outlet of the upper liquid flow plate are in communication with the second liquid inlet and the second liquid outlet of the lower liquid flow plate, and a sealing ring is provided between them. The upper liquid flow plate and the lower liquid flow plate are locked together by screws to clamp the sealing ring and the PTC heating element between the upper liquid flow plate and the lower liquid flow plate.

[0012] In one embodiment, the PTC heating element includes a plurality of heating cores, the plurality of heating cores including a common electrode and a common electrode pin extending from the common electrode and connected to a circuit board.

[0013] In one embodiment, the PTC heating unit includes a circuit board for controlling the operation of the PTC heating element, and a plurality of IGBTs are disposed on the circuit board, wherein the IGBTs are attached to the surface of the liquid flow heat exchange unit.

[0014] In one embodiment, the circuit board is disposed below the lower flow plate, and the IGBT is attached to the substrate of the lower flow plate via a heat-conducting component.

[0015] In one embodiment, the PTC heater assembly further includes a resilient press-fit member that resiliently presses against the IGBT to maintain contact between the IGBT and the lower flow plate.

[0016] In one embodiment, the PTC heater assembly includes a housing with a chamber, the top of the housing being an opening, an upper flow plate being connected to the housing and covering the opening of the housing to form an upper cover of the PTC heater assembly, and the PTC heating unit and the lower flow plate being located within the chamber of the housing.

[0017] In one embodiment, the outer casing has a plurality of support columns protruding into the cavity, the support columns abutting against the lower fluid flow plate.

[0018] The PTC heater assembly provided in this application uses an upper liquid flow plate and a lower liquid flow plate to clamp the PTC heating element, so that the heating surfaces on both sides of the PTC heating element respectively transfer heat to the upper liquid flow plate and the lower liquid flow plate to heat the liquid in the upper liquid flow channel and the lower liquid flow channel. This results in a low height, high heat utilization rate and high heat transfer efficiency of the PTC heater assembly.

[0019] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology 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.

[0021] Figure 1 is a perspective view of an embodiment of the PTC heater assembly provided in this application.

[0022] Figure 2 is a perspective view of another embodiment of the PTC heater assembly provided in this application.

[0023] Figure 3 is an exploded perspective view of an embodiment of the PTC heater assembly provided in this application.

[0024] Figure 4 is an exploded perspective view of another embodiment of the PTC heater assembly provided in this application.

[0025] Figure 5 is a cross-sectional view of an embodiment of the PTC heater assembly provided in this application.

[0026] Figure 6 is another cross-sectional view of an embodiment of the PTC heater assembly provided in this application.

[0027] Figure 7 is a cross-sectional view of another embodiment of the PTC heater assembly provided in this application.

[0028] The component reference numerals are as follows: 100, PTC heater assembly; 10, outer casing; 101, chamber; 11, high-pressure interface; 12, low-pressure interface; 13, support column; 14, opening; 20, liquid flow heat exchange unit; 201, inlet pipe; 202, outlet pipe; 21, upper liquid flow plate; 210, upper liquid flow channel; 211, upper base plate; 212, upper fin; 213, upper cover plate; 214, first liquid inlet; 215, first liquid outlet; 216, flow channel; 22, lower liquid flow plate; 220, lower liquid flow channel; 221, lower base plate; 222, lower fin; 223, lower cover plate; 224, second liquid inlet; 225, second liquid outlet. 23. Liquid inlet; 24. First insulating film; 25. Second insulating film; 26. Third insulating film; 27. Connecting flange; 38. Sealing ring; 39. PTC heating unit; 30. PTC heating element; 310. Insulating sleeve; 311. Common electrode; 312. Dividing electrode; 313. Common electrode pin; 314. Dividing electrode pin; 32. Circuit board; 33. IGBT; 331. Elastic crimping component; 332. Thermal conductive component; 333. Pad; 34. Temperature sensor. Detailed Implementation

[0029] 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.

[0030] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0031] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.

[0035] Please refer to Figures 1 to 6. This application provides a PTC heater assembly 100, which includes a housing 10, a PTC heating unit 30, and a liquid flow heat exchange unit 20 that is thermally connected to the PTC heating unit 30. The PTC heating unit 30 and the liquid flow heat exchange unit 20 are assembled onto the housing 10. The PTC heating unit 30 generates heat, heating the liquid in the liquid flow heat exchange unit 20. The liquid in the liquid flow heat exchange unit 20 exchanges heat with other components to be heated, thus achieving heat transfer.

[0036] Please refer to Figures 3 to 6 for details. The liquid flow heat exchange unit 20 includes an upper liquid flow plate 21 and a lower liquid flow plate 22. An upper liquid flow channel 210 is formed in the upper liquid flow plate 21, and a lower liquid flow channel 220 is formed in the lower liquid flow plate 22. The PTC heating unit includes a PTC heating element 31 sandwiched between the upper liquid flow plate 21 and the lower liquid flow plate 22. The heating surfaces on both sides of the PTC heating element 31 transfer heat to the upper liquid flow plate 21 and the lower liquid flow plate 22, respectively, to heat the liquid in the upper liquid flow channel 210 and the lower liquid flow channel 220.

[0037] The PTC heater assembly 100 provided in this application uses an upper liquid flow plate 21 and a lower liquid flow plate 22 to clamp the PTC heating element 31, so that the heating surfaces on both sides of the PTC heating element 31 respectively transfer heat to the upper liquid flow plate 21 and the lower liquid flow plate 22 to heat the liquid in the upper liquid flow channel 210 and the lower liquid flow channel 220, resulting in a low height, high heat utilization rate and high heat transfer efficiency of the PTC heater assembly 100.

[0038] In this embodiment, the upper liquid flow plate 21 and the lower liquid flow plate 22 respectively include a base plate with a tortuous flow channel, fins disposed within the tortuous flow channel, and a cover plate sealingly covering the base plate. Specifically, the upper liquid flow plate 21 includes an upper base plate 211, an upper cover plate 213, and upper fins 212; the upper base plate 211 is stamped to form a serpentine flow channel to increase the tortuosity of the liquid flow and enhance heat exchange; the upper fins 212 are disposed within the serpentine flow channel to increase turbulence and enhance heat exchange; the upper cover plate 213 is flat and covers the upper base plate 211 and is sealed together to form the upper liquid flow channel 210. In one embodiment, both the upper base plate 211 and the upper cover plate 213 are aluminum plates, which are welded together to form a seal. The upper fins 212 can also be made of aluminum, and their shape and structure can be set according to specific requirements to meet the required heat exchange capacity and water resistance. The upper substrate 211 and the upper cover plate 213 are provided with corresponding first liquid inlet 214 and first liquid outlet 215. The first liquid inlet 214 and the first liquid outlet 215 on the upper substrate 211 are respectively connected to the liquid inlet pipe 201 and the liquid outlet pipe 202. The first liquid inlet 214 and the first liquid outlet 215 on the upper cover plate 213 are respectively connected to the second liquid inlet 224 and the second liquid outlet 225 of the lower liquid flow plate 22.

[0039] The structure of the lower flow plate 22 is similar to that of the upper flow plate 21. Specifically, the lower flow plate 22 includes a lower base plate 221, a lower cover plate 223, and lower fins 222. The lower base plate 221 is stamped to form a serpentine flow channel to increase the tortuosity of the liquid flow and enhance heat exchange. The lower fins 222 are disposed within the serpentine flow channel to increase turbulence and enhance heat exchange. The lower cover plate 223 is flat and covers the lower base plate 221 and is sealed to form the lower flow channel 220. In one embodiment, both the lower base plate 221 and the lower cover plate 223 are aluminum plates, which are welded together to form a seal. The lower fins 222 can also be made of aluminum, and their shape and structure can be set according to specific requirements to meet the required heat exchange capacity and water resistance. The lower substrate 221 has a second liquid inlet 224 and a second liquid outlet 225, which communicate with the first liquid inlet 214 and the first liquid outlet 215 on the upper liquid flow plate 21. This allows liquid to flow into the upper liquid flow plate 21 and the lower liquid flow plate 22 through the liquid inlet pipe 201, and liquid in the upper liquid flow plate 21 and the lower liquid flow plate 22 to flow out through the liquid outlet pipe 202. The first liquid inlet 214 and the first liquid outlet 215 of the upper liquid flow plate 21 are connected to the second liquid inlet 224 and the second liquid outlet 225 of the lower liquid flow plate 22, and a sealing ring 27 is provided between them to achieve a seal and prevent liquid leakage.

[0040] In this embodiment, the upper liquid flow plate 21 and the lower liquid flow plate 22 are assembled in a manner where the upper cover plate 213 and the lower cover plate 223 are flat and opposite to each other. The PTC heating element 31 is clamped between the upper liquid flow plate 21 and the lower liquid flow plate 22. The upper liquid flow plate 21 and the lower liquid flow plate 22 are locked together with screws to clamp the sealing ring 27 and the PTC heating element 31 between the upper liquid flow plate 21 and the lower liquid flow plate 22. This not only seals the water passage but also reduces the gap between the PTC heating element 31 and the upper and lower liquid flow plates, allowing heat to be transferred more quickly from the PTC heating element 31 to the liquid flow plates on both sides, thereby achieving higher heat transfer efficiency. Specifically, the upper cover plate 213 of the upper liquid flow plate 21 has a connecting flange 26 welded around its first liquid inlet 214 and first liquid outlet 215. The connecting flange 26 has threaded holes for screw connection, and an O-ring groove is provided on the bottom surface of the connecting flange 26 to install an O-ring seal to seal the second liquid inlet 224 and second liquid outlet 225 of the upper and lower liquid flow plates. The height of the connecting flange 26 is consistent with the thickness of the PTC heating element, so that the PTC heating element 31 is pressed while the sealing ring 27 is assembled and tightened. The lower cover plate 223 of the lower liquid flow plate 22 has a small hole for installing a temperature sensor 34. The temperature sensor 34 protrudes into the liquid flow heat exchange unit 20 to detect the liquid temperature. In one embodiment, the base plate, cover plate, fins, connecting flange 26, and liquid inlet pipe 201 and liquid outlet pipe 202 of the above-mentioned upper and lower liquid flow plates can be welded together by means of brazing, brazing-free brazing, or vacuum brazing.

[0041] In this embodiment, the length and width of the upper liquid flow plate 21 are greater than the length and width of the lower liquid flow plate 22. During assembly, the upper liquid flow plate 21 can overlap the edge of the opening 14 of the outer shell 10 to connect and fix it to the outer shell 10, while the lower liquid flow plate 22 is located inside the outer shell 10. Since both the upper liquid flow plate 21 and the lower liquid flow plate 22 in this application are plate-shaped with small thickness and occupy little space, they are suitable for use in narrow spaces. The PTC heating element 31 is sandwiched between them, and both heating surfaces of the PTC heating element 31 transfer heat to the liquid flow heat exchange unit 20, resulting in high thermal efficiency.

[0042] Please refer to Figures 3 and 4. Further, an insulating film is provided between the upper liquid flow plate 21 and the lower liquid flow plate 22 and the PTC heating element 31. The insulating film provides insulation, enhancing the electrical safety of the PTC heating element 31. The insulating film includes a first insulating film 23 disposed between the upper liquid flow plate 21 and the PTC heating element 31, and a second insulating film 24 disposed between the PTC heating element 31 and the lower liquid flow plate 22. In this embodiment, both the first insulating film 23 and the second insulating film 24 are polyimide films (PI films), which have good insulation properties, thin thickness, light weight, and good thermal conductivity. The first insulating film 23 is attached to the upper cover plate 213 of the upper liquid flow plate 21, and the second insulating film 24 is attached to the lower cover plate 223 of the lower liquid flow plate 22. Thermally conductive adhesive is printed on both sides of the PTC heating element 31 and bonded to the first insulating film 23 and the second insulating film 24, respectively.

[0043] Please refer to Figure 4 for details. In this embodiment, the PTC heating unit 30 includes a PTC heating element 31 and a circuit board 32 for controlling the operation of the PTC heating element 31. The PTC heating element 31 includes multiple heating cores, each including a common electrode 311 and multiple segmented electrodes 312. A common electrode pin 313 extends from the common electrode 311 and connects to the circuit board 32. Multiple segmented electrode pins 314 extend from each of the segmented electrodes 312 and connect to the circuit board 32, respectively. By setting the common electrode 311 and common electrode pins 313, this embodiment reduces the total number of pins, allows for direct soldering of pins, eliminates the need for a busbar adapter, and reduces the number of components. In this embodiment, the electrodes are copper sheet electrodes, and the electrode pins are bent at 90° and directly inserted into the circuit board 32 for soldering. Insulating sleeves 310 are also fitted onto the common electrode pin 313 and the segmented electrode pins 314 to increase insulation performance and prevent insulation failure caused by insufficient gap between the pins and the flow plate.

[0044] Please refer to Figures 3 to 6. In this embodiment, the circuit board 32 is disposed below the lower liquid flow plate 22. The pins of the PTC heating element 31 extend downward from the outer edge of the lower liquid flow plate 22 and are inserted into the circuit board 32. A third insulating film 25 is also disposed between the circuit board 32 and the lower liquid flow plate 22 to enhance the electrical safety of the circuit board 32. Furthermore, a plurality of IGBTs (Insulate-Gate Bipolar Transistors) 33 are disposed on the circuit board 32, wherein the IGBTs 33 are attached to the surface of the liquid flow heat exchange unit 20. Specifically, the IGBTs 33 are attached to the lower substrate 221 of the lower liquid flow plate 22 through a thermal conductive element 332. In this way, the lower liquid flow plate 22 can quickly and efficiently dissipate heat from the IGBTs 33, preventing overheating of the IGBTs 33 and ensuring normal operation of the IGBTs 33. The thermal conductive element 332 can be thermally conductive silicone, a thermal pad, etc. The PTC heater assembly 100 further includes an elastic pressing member 331 that elastically presses against the IGBT 33 to maintain contact between the IGBT 33 and the lower flow plate 22. The elastic pressing member 331 is mounted below the circuit board 32, and a pad 333 is provided between it and the circuit board 32 to prevent damage to the circuit board 32. The elastic pressing member 331 has several elastic tabs that pass through openings in the circuit board 32 to abut against the IGBT 33.

[0045] Please refer to Figures 3 to 6. The PTC heater assembly 100 includes a housing 10 with a chamber 101. The housing 10 is a generally rectangular box with an opening 14 at the top. The upper liquid flow plate 21 is connected to the housing 10 and covers the opening 14 to form the upper cover of the PTC heater assembly 100. The PTC heating unit 30 and the lower liquid flow plate 22 are located within the chamber 101 of the housing 10. Using the upper liquid flow plate 21 as the outer cover of the assembly reduces the number of components and increases space utilization. Referring to Figure 7, in another embodiment, the housing 10 also has several support columns 13 protruding into the chamber 101. The support columns 13 abut against the lower liquid flow plate 22, pressing it down to prevent loosening between the lower liquid flow plate 22 and the PTC heating element 31 during vibration. The outer casing 10 is also provided with a high-voltage interface 11 and a low-voltage interface 12 on its side for electrical connection with other external electrical components. The outer casing 10 can be made of plastic or cast aluminum. The outer casing 10 has several threaded connection parts around its perimeter, some for connecting to the upper liquid flow plate 21, and some for installing the PTC heater assembly 100 onto the client.

[0046] As can be seen from the above description of the specific embodiments, the PTC heater assembly 100 provided in this application uses an upper liquid flow plate 21 and a lower liquid flow plate 22 to clamp the PTC heating element 31, so that the heating surfaces on both sides of the PTC heating element 31 respectively transfer heat to the upper liquid flow plate 21 and the lower liquid flow plate 22 to heat the liquid in the upper liquid flow channel 210 and the lower liquid flow channel 220. This results in a PTC heater assembly 100 with low height, high heat utilization rate and heat transfer efficiency, and can reduce the number of parts, with a simpler structure, lighter weight and correspondingly lower cost.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.

Claims

1. A PTC heater assembly, comprising a PTC heating unit and a liquid flow heat exchange unit thermally connected with the PTC heating unit, characterized in that, The liquid flow heat exchange unit includes an upper liquid flow plate and a lower liquid flow plate. An upper liquid flow channel is formed in the upper liquid flow plate, and a lower liquid flow channel is formed in the lower liquid flow plate. The PTC heating unit includes a PTC heating element sandwiched between the upper and lower liquid flow plates. The heating surfaces on both sides of the PTC heating element transfer heat to the upper and lower liquid flow plates respectively to heat the liquid in the upper and lower liquid flow channels.

2. The PTC heater assembly according to claim 1, wherein, The upper flow plate and the lower flow plate each include a substrate with a tortuous flow channel, fins disposed in the tortuous flow channel, and a cover plate sealing the substrate.

3. The PTC heater assembly according to claim 1, wherein, An insulating film is provided between the upper liquid flow plate and the lower liquid flow plate and the PTC heating element.

4. The PTC heater assembly according to claim 1, wherein, The upper and lower liquid flow plates are respectively provided with a second liquid inlet and a second liquid outlet. The first liquid inlet and the first liquid outlet of the upper liquid flow plate are connected to the second liquid inlet and the second liquid outlet of the lower liquid flow plate, and a sealing ring is provided between them. The upper and lower liquid flow plates are locked together by screws to clamp the sealing ring and the PTC heating element between the upper and lower liquid flow plates.

5. The PTC heater assembly according to claim 1, wherein, The PTC heating element includes multiple heating cores, each including a common electrode and a common electrode pin extending from the common electrode and connected to a circuit board.

6. The PTC heater assembly according to claim 2, wherein, The PTC heating unit includes a circuit board for controlling the operation of the PTC heating element. Several IGBTs are disposed on the circuit board, wherein the IGBTs are attached to the surface of the liquid flow heat exchange unit.

7. The PTC heater assembly according to claim 6, wherein, The circuit board is disposed below the lower flow plate, and the IGBT is attached to the substrate of the lower flow plate through a heat-conducting component.

8. The PTC heater assembly according to claim 7, wherein, The PTC heater assembly also includes an elastic pressing member that elastically presses against the IGBT to maintain contact between the IGBT and the lower flow plate.

9. The PTC heater assembly according to claim 1, wherein, The PTC heater assembly includes a housing with a chamber, the top of the housing being an opening, an upper flow plate being connected to the housing and covering the opening of the housing to form an upper cover of the PTC heater assembly, and the PTC heating unit and the lower flow plate being located within the chamber of the housing.

10. The PTC heater assembly according to claim 9, wherein, The outer shell has a plurality of support columns protruding into the cavity, the support columns abutting against the lower fluid flow plate.

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