Heating bag for liquid PTC heater

Abstract

The utility model discloses a heating bag for a liquid PTC heater. The PTC heater comprises a heating shell and PTC heating bags, the heating shell comprises an upper shell body and a lower shell body, the upper shell body and the lower shell body are spliced to form a liquid circulation cavity in a surrounding mode, the upper shell body is provided with a plurality of heater grooves penetrating into the liquid circulation cavity, the PTC heating bags are inserted into the heater grooves, the PTC heating bags comprise PTC heating pieces fixed in a PTC plastic-coated fixing frame, and the PTC heating pieces are connected with the PTC plastic-coated fixing frame. The PTC heating sheet is bonded, fixed and in conductive contact with the electrode sheets on the two sides through a bonding glue layer coated on the surface of the PTC heating sheet, wedge blocks are inserted between the electrode sheets on the two sides and the heater groove, and insulating silica gel is filled in a gap of the heater groove. The PTC heater has the advantages that the heat efficiency of the PTC heating sheet is improved, the risk of faults caused by condensate water is reduced, gaps are filled with bi-component high-thermal-conductivity silica gel, the problem of insulation failure caused by penetration of the condensate water is further avoided, and the operation safety of the whole heater is improved.

Description

Technical Field

[0001] This utility model belongs to the field of PTC heating technology, and in particular relates to a heating pack for a liquid PTC heater. Background Technology

[0002] With global economic development, the increasing depletion of fossil fuels, and the environmental pollution caused by traditional automobiles, electric, hybrid, and range-extended vehicles powered by batteries and hydrogen energy have become a growing trend in green transportation. New energy vehicles have gained widespread recognition for their ability to address the environmental pollution problems of traditional gasoline-powered vehicles and have been included in national industrial development plans. Replacing traditional gasoline vehicles is an inevitable trend, with major OEMs accelerating their transformation and entering this field, while emerging car manufacturers are continuously improving related technologies. In traditional gasoline-powered vehicles, the heaters used for winter heating typically utilize waste heat from exhaust gases or engine cooling water as a heat source, introducing it into a heat exchanger. Air supplied by a blower exchanges heat with the heat exchanger, and the heated air is then delivered into the vehicle to achieve heating, defogging, defrosting, and heating other components requiring heat. This heating method is characterized by a complex heating system, low thermal efficiency, and slow heating speed. Unlike traditional gasoline-powered vehicles, new energy vehicles require independent heaters for their battery panel heating and air conditioning systems. Meanwhile, with the continuous development of the battery industry, batteries, as the core component of new energy storage technologies, play a crucial role in improving the utilization rate of renewable energy and ensuring the stable operation of the power system. They dominate the energy storage market, primarily used to eliminate day-night peak-valley differences, and their lifespan directly affects the economic benefits of projects. Battery temperature is critical for the safe and stable operation of batteries. Precise temperature regulation ensures they operate within a suitable range, typically 23-25°C, achieving maximum efficiency. Simultaneously, the uniformity of temperature distribution within the battery pack and system safety are ensured through the integration of various safety functions to prevent potential safety hazards. In low-temperature environments, when the battery temperature drops below -10°C, the battery enters a "hibernation" mode and cannot function normally. At this time, a heater is used as the heat supply for the thermal management system to ensure the battery can operate normally in low-temperature environments.

[0003] PTC (Positive Temperature Coefficient) semiconductor material exhibits a rapid increase in resistivity when the temperature reaches near the Curie temperature of the PTC element. PTC heaters are characterized by fast start-up, high thermal efficiency, good temperature control, safety without open flame, ideal reliability, energy saving, and long service life. As a safe electric heating product, PTC has been widely used and is considered a relatively ideal electric heating material. However, during use, due to poor heat dissipation of the PTC sheet, the operating point of the PTC element can easily exceed the maximum resistance-temperature characteristic point, entering the NTC stage. This leads to a rapid temperature rise and thermal breakdown of the PTC element, resulting in insulation failure in the heater and affecting the operation of the heating system. Therefore, improving the heat dissipation capacity of PTC as a heating element is a crucial consideration. Currently, liquid heaters in the new energy vehicle and energy storage markets widely adopt a closed cavity combination of a die-cast body and a plastic water tank. Antifreeze flowing within the circulating cavity acts as a heat carrier, carrying away the heat generated by the PTC heating pack in the heater's heating chamber, providing heat for the air conditioning, batteries, and energy storage products of new energy vehicles.

[0004] Current mainstream PTC heating elements consist of a central PTC heating element and an insulating film and clamping wedges arranged sequentially from the inside out. In this structure, polyimide is used as the insulating and thermally conductive material for the insulating film. Polyimide itself has a low thermal conductivity. To ensure the heat dissipation effect of the PTC heating element, the insulating film must be made relatively thin. This makes the insulating film susceptible to puncture by foreign objects embedded within it under thermal shock conditions during production and use, leading to insulation failures between the electrodes and the inner wall of the heat-conducting groove. Simultaneously, condensation may accumulate in the gap between the heating element and the groove under alternating hot and cold environments, reducing the creepage distance between the live parts of the heater and the die-cast body, resulting in short circuits between the heating element electrodes or insulation failures between the heating element electrodes and the die-cast body. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to provide a heating pack for a liquid PTC heater that can reduce production costs, improve production efficiency, increase the heat conversion efficiency and power density of PTC heating elements, reduce the risk of PTC heating element explosion, eliminate the gap in the heating pack in the die-casting groove, and reduce the risk of insulation failure of PTC heating pack due to condensation.

[0006] To solve the above-mentioned technical problems, the present invention provides a heating pack for a liquid PTC heater, comprising a heating shell and a PTC heating pack. The heating shell includes an upper shell and a lower shell, which are joined together to form a liquid circulation cavity. The upper shell has several heater slots that extend into the liquid circulation cavity. A PTC heating pack is inserted into the heater slot. The PTC heating pack includes a PTC heating element fixed in a PTC plastic-coated fixing frame. The PTC heating element is bonded and fixed to the electrode plates on both sides by an adhesive layer coated on its surface and makes conductive contact. Wedge-shaped blocks are inserted between the electrode plates on both sides and the heater slot. The gaps in the heater slot are filled with insulating silicone.

[0007] One side electrode of the PTC heating element is a PTC plastic-coated fixing frame electrode, which is integrally molded with the PTC plastic-coated fixing frame.

[0008] The lower housing is provided with an inlet and an outlet pipe on each side, which are connected to the liquid circulation chamber.

[0009] The insulating silicone is made of two-component high thermal conductivity silicone.

[0010] The PTC plastic-coated bracket is a composite material made of PPS glass fiber.

[0011] The wedge block is made of ceramic, the angle of inclination of the wedge block slope ranges from 1° to 1.5°, and the thickness is not less than 1.0 mm.

[0012] Advantages of this utility model:

[0013] (1) Improve the thermal efficiency of PTC heating element: The adhesive layer made of high temperature silicone is used to bond the structure of PTC heating element, and the electrode sheet is pressed by ceramic wedge block, which effectively improves the thermal conductivity of PTC element, makes electrothermal conversion more complete, and the power density is higher, while avoiding the problem of exploding and thermal breakdown caused by local overheating.

[0014] (2) Reduce the risk of failure caused by condensation: The ceramic wedge not only has high thermal conductivity, but also excellent electrical insulation performance. After replacing the traditional insulating film, it significantly improves the insulation strength. Combined with two-component high thermal conductivity silicone to fill the gaps, it further avoids the problem of insulation failure caused by condensation seepage and improves the overall safety of the machine operation.

[0015] (3) Improve overall heat dissipation efficiency and structural strength: The heating pack and the heater tank are sealed with two-component high thermal conductivity silicone (thermal conductivity not less than 3W / m·K), which effectively eliminates assembly gaps, ensures that heat is uniformly and quickly conducted to the liquid circulation chamber, improves the heat dissipation efficiency of the shell, and enhances the structural tightness and stability. Attached Figure Description

[0016] Figure 1This is an assembly drawing of the external components of the heating pack for the liquid PTC heater of this utility model;

[0017] Figure 2 This is an exploded view of the PTC heating pack in the heating pack for the liquid PTC heater of this utility model;

[0018] Figure 3 This is a partial exploded view of the PTC heating pack in the heating pack of the liquid PTC heater of this utility model;

[0019] Figure 4 This is a cross-sectional view of the PTC heating element in the heating pack of the liquid PTC heater of this utility model. Detailed Implementation

[0020] The heating pack for the liquid PTC heater of this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0021] The present invention relates to a heating pack for a liquid PTC heater, comprising a heating shell and a PTC heating pack 1. The heating shell includes an upper shell 2 and a lower shell 3, which are connected to form a liquid circulation chamber 4. The upper shell 2 has several heater slots 5 extending into the liquid circulation chamber 4. The heater slots 5 are separated from the liquid circulation chamber 4 by an isolation wall 11. The PTC heating pack 1 is inserted in the heater slots 5 to convert electrical energy into heat energy and heat the liquid flowing in the liquid circulation chamber 4. The PTC heating pack 1 includes a PTC heating element 6 fixed in a PTC plastic-coated fixing frame 9. The PTC heating element 6 is bonded and fixed to two electrode plates 8 on both sides by an adhesive layer 7 coated on its surface and makes conductive contact. One electrode plate 8 of the PTC heating element 6 is a PTC plastic-coated fixing frame electrode plate integrally molded with the PTC plastic-coated fixing frame 9. The electrode plate is heated or energized by the electrode plate. The PTC heating element 6 is firmly bonded to the PTC plastic-coated fixing bracket electrode sheet; wedge-shaped blocks 10 are inserted between the electrode sheets 8 on both sides and the heater groove 5. The wedge-shaped blocks 10 are made of ceramic, and the inclined angle of the wedge-shaped blocks 10 is in the range of 1°~1.5°, and the thickness is not less than 1.0mm. The two sides of the wedge-shaped blocks 10 and the gap between the PTC heating element 1 and the heater groove 5 are filled with insulating silicone 13 to prevent condensation from seeping in. The insulating silicone 13 is made of two-component high thermal conductivity silicone with a concentration of not less than 3W / (m·K). First, thermosetting insulating silicone is injected into the heater groove 5, and then the PTC heating element 1 is inserted. Under pressure, the insulating silicone 13 fills the gap and is heated and cured; the plastic of the PTC plastic-coated fixing bracket 9 is made of PPS glass fiber material. The lower shell 3 has a water inlet 14 and a water outlet 15 on both sides that are connected to the liquid circulation chamber 4.

Claims

1. A heating pack for a liquid PTC heater, characterized in that: The device includes a heating shell and a PTC heating pack (1). The heating shell includes an upper shell (2) and a lower shell (3). The upper shell (2) and the lower shell (3) are joined together to form a liquid circulation cavity (4). The upper shell (2) is provided with several heater slots (5) that extend into the liquid circulation cavity (4). The PTC heating pack (1) is inserted in the heater slots (5). The PTC heating pack (1) includes a PTC heating element (6) fixed in a PTC plastic-coated fixing frame (9). The PTC heating element (6) is bonded and fixed to the electrode plates (8) on both sides through an adhesive layer (7) coated on the surface and makes conductive contact. Wedge blocks (10) are inserted between the electrode plates (8) on both sides and the heater slots (5). The gaps in the heater slots (5) are filled with insulating silicone (13).

2. The heating pack for a liquid PTC heater according to claim 1, characterized in that: The electrode plate (8) on one side of the PTC heating element (6) is a PTC plastic-coated fixing frame electrode plate integrally formed with the PTC plastic-coated fixing frame (9) by injection molding.

3. The heating pack for a liquid PTC heater according to claim 1, characterized in that: The lower housing (3) is provided with an inlet (14) and an outlet (15) on both sides, which are connected to the liquid circulation chamber (4).

4. The heating pack for a liquid PTC heater according to claim 1, characterized in that: The insulating silicone (13) is made of two-component high thermal conductivity silicone.

5. The heating pack for a liquid PTC heater according to claim 1, characterized in that: The PTC plastic-coated fixing frame (9) is a composite material of PPS glass fiber.

6. The heating pack for a liquid PTC heater according to claim 1, characterized in that: The wedge block (10) is made of ceramic, and the inclined angle of the wedge block (10) is in the range of 1°~1.5°, and the thickness is not less than 1.0mm.

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