Over-temperature protection fuse for photovoltaic off switch 1500v direct current system
Patent Information
- Application Number
- CN202522563481.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-02
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-12-02
AI Technical Summary
In existing 1500V DC photovoltaic circuit breakers, the solder joints between the outgoing wires and the conductive housing are not firm due to factors such as temperature changes and mechanical vibrations, which affects the normal operation of the thermal fuse and poses a safety hazard.
The design incorporates a protrusion and a fixing groove at the end of the connector wire to achieve mechanical snap-fit fixing between the connector wire and the conductive housing, eliminating the traditional welding method and enhancing connection reliability and sealing through the groove structure.
It effectively avoids problems such as loose or cracked solder joints, ensures reliable disconnection of the thermal fuse in a 1500V DC system, reduces the risk of arc reignition and electrical breakdown, and improves safety and reliability.
Smart Images
Figure CN224934715U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of fuses, and in particular to an over-temperature protection fuse for a 1500V DC photovoltaic shutdown system. Background Technology
[0002] With the booming development of the new energy industry, the application of photovoltaic panels is becoming increasingly widespread, and their numbers are increasing dramatically. However, photovoltaic panels pose safety hazards such as combustion during use, which brings serious challenges to their safe operation. To ensure the safe use of photovoltaic panels, circuit breakers have emerged. Circuit breakers can monitor and control signal voltage and ambient temperature in real time. Once an abnormality is detected, they can quickly cut off the output of the photovoltaic panel, causing the output voltage to drop below the safe voltage value within a specified time. This effectively protects the personal safety of relevant users and fire rescue personnel, playing a crucial role in the field of photovoltaic panel safety protection.
[0003] In related technologies, to further enhance the safety performance of the circuit breaker, a temperature fuse for a 1500V DC system is connected in series inside the circuit breaker. The temperature fuse is ingeniously designed, with a temperature sensor fixed on one side of its conductive housing and a movable electrode slidably mounted on the other side, connected by a first spring. A conductive retaining ring is located around the movable electrode, and a second spring is also fitted around it. An insulating sleeve is located at a corresponding position on the inner wall of the conductive housing. The two ends of the second spring abut against the conductive retaining ring and the insulating sleeve, respectively, and both the first and second springs are in a compressed state. The conductive housing is connected to an input line and an output line at both ends. During normal operation, the current flows along a specific path. In the event of a short circuit, the temperature sensor melts, and the first and second springs activate, disconnecting the movable electrode from the input line and ensuring the circuit breaker's operation.
[0004] In the aforementioned technologies, welding is typically used to fix the outgoing wires and conductive housing. However, this welding method has significant drawbacks in actual use. Due to the complex working environment of the circuit breaker, the solder joints are prone to becoming unstable after long-term operation due to various factors. For example, temperature changes and mechanical vibrations may cause the solder joints to loosen or crack, thereby affecting the normal operation of the thermal fuse, reducing its protective effect on the circuit breaker, and posing a hidden danger to the safe operation of the photovoltaic panel. There is room for improvement. Summary of the Invention
[0005] The purpose of this application is to provide an over-temperature protection fuse for a 1500V DC system of a photovoltaic shutdown device, which solves the problem in the above-mentioned related technologies that, after long-term operation, the solder joints between the outgoing wires and the conductive housing are not firm, which affects the normal operation of the thermal fuse.
[0006] The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system provided in this application adopts the following technical solution: An over-temperature protection fuse for a 1500V DC photovoltaic switch includes a conductive housing. Inside the conductive housing, a temperature sensor is fixed on one side, a movable electrode slides on the other side, and a first spring is located between the temperature sensor and the movable electrode. A conductive retaining ring is fixed on the outer circumferential surface of the movable electrode, abutting against the inner wall of the conductive housing. A second spring is sleeved on the outer circumferential surface of the movable electrode. An insulating sleeve is fixed on the inner wall of the conductive housing, located outside the movable electrode. The two ends of the second spring abut against the conductive retaining ring and the insulating sleeve, respectively. Both the first and second springs are in a compressed state. An access line connecting to the movable electrode and an output line connecting to the temperature sensor are fixed at both ends of the conductive housing, respectively. A protrusion is fixed at the end of the output line near the conductive housing, and a fixing annular groove is formed on the outer circumferential surface of the protrusion. The end of the conductive housing away from the access line can be engaged in the fixing annular groove.
[0007] By adopting the above technical solution, a mechanical snap-fit fixation is achieved between the outlet wire and the conductive housing by setting a protrusion and a fixing annular groove at the end of the outlet wire and inserting the end of the conductive housing into the annular groove. This design abandons the traditional welding method, effectively avoiding the problem of loosening or cracking of the solder joints caused by factors such as temperature changes and mechanical vibration, significantly improving the connection reliability, and effectively preventing the circuit from being disconnected in time when the temperature rises in the 1500V DC system.
[0008] Optionally, when the temperature sensing element melts, the second spring can push the movable electrode to move closer to the contact line. The first spring can move as a whole closer to the contact line under the push of the movable electrode. At this time, the end of the movable electrode away from the conductive retaining ring can be disconnected from the end of the contact line inserted into the conductive housing. The distance between the end of the movable electrode away from the conductive retaining ring and the end of the contact line inserted into the conductive housing is not less than 8mm.
[0009] By adopting the above technical solution, this design ensures that the movable electrode and the end of the access line can be quickly and reliably disconnected. Furthermore, by setting the disconnection distance between the two to be no less than 8mm, the risk of continuous conduction caused by arc reignition or small gaps is effectively avoided, significantly improving the current breaking safety of the fuse. In addition, the 8mm safety distance design meets the insulation requirements in high-voltage environments, preventing secondary faults caused by insufficient disconnection distance, and providing more reliable technical protection for the over-temperature protection of photovoltaic power switches in 1500V DC systems.
[0010] Optionally, the conductive retaining ring has a wear-resistant layer on the side near the first spring.
[0011] By adopting the above technical solution, in the manufacturing process of the thermal fuse, the conductive retaining ring and the first spring need to go through multiple assembly and debugging processes. During this process, relative sliding, collision and other contact actions may occur between the conductive retaining ring and the first spring. The wear-resistant layer can reduce the wear of the conductive retaining ring side due to these contacts. If the side of the conductive retaining ring has scratches, unevenness and other defects due to wear, it may affect the fitting accuracy with the first spring, and thus affect the overall performance of the thermal fuse.
[0012] Optionally, the conductive retaining ring has guide arc surfaces on both sides near the inner wall of the conductive housing.
[0013] By adopting the above technical solution, guide arc surfaces are set on both sides of the conductive retaining ring near the inner wall of the conductive housing, which can effectively guide the movable electrode to maintain precise alignment with the inner wall of the conductive housing during the sliding process, avoiding jamming or displacement caused by mechanical vibration or assembly errors.
[0014] Optionally, a sealing resin extending to the middle of the outer peripheral surface of the access line is fixed on the middle portion of the outer peripheral surface of the conductive housing.
[0015] By adopting the above technical solution, the sealing resin can effectively lengthen the electrical gap between the access line and the conductive shell. By increasing this gap distance, the risk of electrical breakdown under high voltage environment is significantly reduced.
[0016] Optionally, the conductive housing is provided with a sealing strip on the outside, one end of which is fixedly connected to the outer peripheral surface of the sealing resin, and the other end is fixedly connected to the outer peripheral surface of the conductive housing.
[0017] By adopting the above technical solution, the sealing resin and the sealing strip work together to not only enhance the sealing performance at the connection between the access line and the shell, effectively preventing the intrusion of corrosive media such as water vapor and salt spray, but also compensate for the thermal expansion differences between different materials through the elastic deformation capability of the sealing strip, thus avoiding sealing failure caused by temperature cycling.
[0018] Optionally, a guide ring groove is formed on the outer peripheral surface of the conductive housing, and a positioning ring groove is formed on the outer peripheral surface of the sealing resin. The two ends of the sealing strip can be respectively embedded in the guide ring groove and the positioning ring groove.
[0019] By adopting the above technical solutions, the annular groove structure provides a clear installation guide for the sealing strip, avoids assembly misalignment, and ensures uniform contact of the sealing interface; mechanical locking - after the strip is embedded in the groove, it forms a physical snap-fit effect, which can maintain a stable connection even under long-term vibration or thermal expansion and contraction, and prevents seal failure.
[0020] Optionally, a support ring groove is formed on the outer circumferential surface of the conductive retaining ring, and a support ring groove is formed at the end of the insulating sleeve away from the access line; one end of the second spring can be inserted into and fixed in the support ring groove, and the other end can be inserted into and fixed in the support ring groove.
[0021] By adopting the above technical solutions, the ring groove structure provides a clear installation reference for the spring, ensuring its axial and radial positioning accuracy and avoiding poor contact or stuck action caused by assembly misalignment; the anti-drop design—the mechanical snap-fit effect of the ring groove can prevent the spring from falling off under extreme conditions (such as strong impact or overheating expansion), ensuring that the fuse can reliably trigger action when the temperature sensor melts.
[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. By setting a protrusion and a fixing groove at the end of the lead wire, and inserting the end of the conductive housing into the groove, a mechanical snap-fit fixation between the lead wire and the conductive housing is achieved. This design eliminates the traditional welding method, effectively avoiding the problem of loosening or cracking of the solder joints due to factors such as temperature changes and mechanical vibration, and significantly improving the reliability of the connection; 2. The ring groove structure provides a clear installation guide for the sealing strip, avoiding assembly misalignment and ensuring uniform contact of the sealing interface; mechanical locking - after the strip is embedded in the groove, it forms a physical snap-fit effect, which can maintain a stable connection even under long-term vibration or thermal expansion and contraction, preventing seal failure. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.
[0024] Figure 1 This is a schematic diagram of the overall structure of the conductive housing and the connection wire installation in Embodiment 1 of this application; Figure 2 This is a cross-sectional view of Embodiment 1 of this application illustrating the installation and assembly of the conductive housing and the temperature sensor; Figure 3 This is a cross-sectional view of Embodiment 1 of this application illustrating the installation and assembly of the conductive housing and the access line; Figure 4 This is a cross-sectional view of Embodiment 1 of this application, showing the installation and cooperation of the protrusion and the conductive housing. Figure 5 This is a cross-sectional view of Embodiment 1 of this application illustrating the installation and mating of the conductive retaining ring and the conductive housing; Figure 6This is a cross-sectional structural diagram illustrating the installation and assembly of the sealing strip and sealing resin in Embodiment 2 of this application.
[0025] In the figure, 1. Conductive housing; 11. Inlet wire; 12. Outlet wire; 121. Protrusion; 1211. Fixing ring groove; 13. Guide ring groove; 2. Temperature sensor; 3. Movable electrode; 31. Conductive retaining ring; 311. Wear-resistant layer; 312. Guide arc surface; 313. Support ring groove; 4. First spring; 5. Second spring; 6. Insulating sleeve; 61. Limiting ring groove; 7. Sealing resin; 71. Positioning ring groove; 8. Sealing strip. Detailed Implementation
[0026] The present application will be further described in detail below with reference to all the accompanying drawings.
[0027] Example 1: Reference Figure 1 , Figure 2 and Figure 3 A photovoltaic switch 1500V DC system over-temperature protection fuse includes a conductive housing 1, wherein a temperature sensor 2 is fixedly installed on one side of the conductive housing 1, a movable electrode 3 is slidably arranged on the other side, a first spring 4 is located between the temperature sensor 2 and the movable electrode 3, a conductive retaining ring 31 is fixedly installed on the outer peripheral surface of the movable electrode 3 and abuts against the inner wall of the conductive housing 1, and a second spring 5 is sleeved on the outer peripheral surface of the movable electrode 3, and an insulating sleeve 6 located outside the movable electrode 3 is fixedly installed on the inner wall of the conductive housing 1. The two ends of the second spring 5 abut against the two sides of the conductive retaining ring 31 and the insulating sleeve 6 respectively. The first spring 4 and the second spring 5 are both in a compressed state. The two ends of the conductive housing 1 are respectively fixedly connected to the access line 11 connected to the movable electrode 3 and the output line 12 connected to the temperature sensor 2. When the circuit breaker is running normally, the current flows in from the access line 11, passes through the movable electrode 3, and then from the conductive retaining ring 31 of the movable electrode 3 to the conductive housing 1, and then flows out through the output line 12. The conductive housing 1 is a metal housing. The insulating sleeve 6 is made of ceramic material. When the circuit breaker is in the open state, the insulating sleeve 6 can insulate and separate the access line 11 from the conductive housing 1 and the movable electrode 3, ensuring circuit safety. When the circuit breaker is in normal operation, current flows in from the access line 11, passes through the movable electrode 3 and the conductive retaining ring 31 of the movable electrode 3, and is then conducted to the conductive housing 1, finally flowing out through the output line 12, forming a complete current loop. When a short circuit occurs, the temperature sensing element 2 melts due to heat, and the elastic potential energy compressed by the first spring 4 and the second spring 5 is released instantaneously. The second spring 5 quickly pushes the movable electrode 3 toward the output line 12, and during the movement, the movable electrode 3 further pushes the first spring 4 toward the output line 12. During this process, the end of the movable electrode 3 away from the conductive retaining ring 31 can be precisely disconnected from the end of the access line 11 that is inserted into the conductive housing 1, thereby cutting off the circuit in time and effectively ensuring circuit safety.
[0028] Reference Figure 4 The end of the lead wire 12 near the conductive housing 1 has an integrally formed protrusion 121, wherein a fixing annular groove 1211 is formed on the outer peripheral surface of the protrusion 121. The conductive housing 1 is away from the lead wire 11 (see Figure 3 The end of the wire can be inserted into the fixing ring groove 1211; even if welding is performed on the connection part later, the special design of the fixing ring groove 1211 can effectively enhance the stability of the connection, making it difficult for the wire 12 to separate from the conductive housing 1 during long-term use.
[0029] Reference Figure 2 and Figure 3 When the temperature sensing element 2 melts, the second spring 5 can push the movable electrode 3 to move closer to the output line 12. Under the push of the movable electrode 3, the first spring 4 can move as a whole closer to the output line 12. At this time, the end of the movable electrode 3 away from the conductive retaining ring 31 can be disconnected from the end of the access line 11 inserted into the conductive housing 1. Furthermore, in order to ensure safe and stable use under a 1500V DC system and avoid potential risks caused by excessive distance, the distance between the end of the movable electrode 3 away from the conductive retaining ring 31 and the end of the access line 11 inserted into the conductive housing 1 is set to be no less than 8mm.
[0030] Reference Figure 3 A sealing resin 7 extending to the middle of the outer periphery of the conductive housing 1 is fixedly installed on the middle of the outer periphery of the access line 11. The sealing resin 7 can effectively lengthen the electrical gap between the access line 11 and the conductive housing 1. By increasing this gap distance, the risk of electrical breakdown in a high-voltage environment is significantly reduced.
[0031] Reference Figure 5The conductive retaining ring 31 has a wear-resistant layer 311 on its side near the first spring 4. During the manufacturing process of the thermal fuse, the conductive retaining ring 31 and the first spring 4 need to go through multiple assembly and debugging processes. During this process, relative sliding, collision and other contact actions may occur between the conductive retaining ring 31 and the first spring 4. The wear-resistant layer 311 can reduce the wear on the side of the conductive retaining ring 31 caused by these contacts. If the side of the conductive retaining ring 31 has scratches, unevenness and other defects due to wear, it may affect the fitting accuracy between it and the first spring 4, and thus affect the overall performance of the thermal fuse.
[0032] Reference Figure 5 The conductive retaining ring 31 has guide arc surfaces 312 on both sides near the inner wall of the conductive housing 1. When the movable electrode 3 moves inside the conductive housing 1 under the push of the spring, the conductive retaining ring 31 will slide relative to the inner wall of the conductive housing 1. At this time, the guide arc surface 312 can form a good fit with the inner wall of the conductive housing 1, and the arc surface structure can effectively reduce the frictional resistance during the sliding process.
[0033] The implementation principle of this application embodiment is as follows: Under normal operating conditions, current flows in from the access line 11, passes through the movable electrode 3, the conductive retaining ring 31 and the conductive shell 1 in sequence, and finally flows out from the output line 12, thus forming a complete and stable current loop; once a short circuit fault occurs in the circuit, the temperature sensing element 2 melts rapidly due to heat, and at this time, the elastic potential energy accumulated by the first spring 4 and the second spring 5 is released instantly. The second spring 5 uses its elastic force to push the movable electrode 3 toward the output line 12. During the movement, the movable electrode 3 further pushes the first spring 4, causing the end of the movable electrode 3 away from the conductive retaining ring 31 to disconnect from the end of the input line 11 inserted into the conductive housing 1. In order to ensure safe and reliable circuit disconnection under a 1500V DC system and avoid potential risks, the distance between the two after disconnection is set to be no less than 8mm, so as to achieve timely circuit disconnection.
[0034] Example 2: Reference Figure 6 The difference between this embodiment and Embodiment 1 is that a sealing strip 8 is provided on the outside of the conductive housing 1. One end of the sealing strip 8 is fixedly connected to the outer peripheral surface of the sealing resin 7, and the other end is fixedly connected to the outer peripheral surface of the conductive housing 1. In the actual manufacturing process, due to the influence of various manufacturing process factors such as materials, a certain degree of gap may appear between the sealing resin 7 and the conductive shell 1. At this time, the sealing strip 8 can tightly fill these gaps, effectively preventing external dust, moisture and other impurities from entering the interior of the conductive shell 1, and avoiding faults such as electrical short circuits and reduced insulation performance caused by the intrusion of impurities.
[0035] Reference Figure 6 A guide ring groove 13 is provided on the outer peripheral surface of the conductive housing 1, and a positioning ring groove 71 is provided on the outer peripheral surface of the sealing resin 7. The two ends of the sealing strip 8 can be respectively embedded in the guide ring groove 13 and the positioning ring groove 71. This embedding method forms a stable mechanical connection structure, which effectively prevents the sealing strip 8 from shifting or falling off during use.
[0036] Reference Figure 6 A support ring groove 313 is provided on the outer circumferential surface of the conductive retaining ring 31, and a limiting ring groove 61 is provided at the end of the insulating sleeve 6 away from the access line 11; one end of the second spring 5 can be inserted into and fixed in the support ring groove 313, and the other end can be inserted into and fixed in the limiting ring groove 61; the support ring groove 313 and the limiting ring groove 61 can ensure that the second spring 5 will not be displaced or fall off during use, so that the second spring 5 can provide stable and reliable elastic support between the conductive retaining ring 31 and the insulating sleeve 6.
[0037] The implementation principle of this application embodiment is as follows: During the manufacturing stage, gaps may appear between the sealing resin 7 and the conductive shell 1 due to the influence of materials and processes. At this time, the sealing strip 8 is connected to the outer peripheral surface of the sealing resin 7 at one end and to the outer peripheral surface of the conductive shell 1 at the other end, tightly filling the gap and preventing external dust, moisture and other impurities from entering the interior of the conductive shell 1, thus preventing faults such as electrical short circuits and reduced insulation performance. At the same time, guide ring grooves 13 and positioning ring grooves 71 are respectively opened on the outer peripheral surfaces of the conductive shell 1 and the sealing resin 7, and the two ends of the sealing strip 8 are embedded in them to form a stable mechanical connection structure, preventing the sealing strip 8 from shifting or falling off.
[0038] Unless otherwise defined, the terms or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar words used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "a" or "one," and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising," "including," and similar words mean that the element or object preceding "comprising" encompasses the element or object listed following "comprising" or "including," and their equivalents, but do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0039] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.
Claims
1. An over-temperature protection fuse for a 1500V DC photovoltaic switch, comprising a conductive housing (1), wherein a temperature sensor (2) is fixedly disposed on one side of the conductive housing (1), a movable electrode (3) is slidably disposed on the other side, and a first spring (4) is located between the temperature sensor (2) and the movable electrode (3), a conductive retaining ring (31) is fixedly disposed on the outer peripheral surface of the movable electrode (3) and abuts against the inner wall of the conductive housing (1), a second spring (5) is sleeved on the outer peripheral surface of the movable electrode (3), and an insulating sleeve (6) located outside the movable electrode (3) is fixedly disposed on the inner wall of the conductive housing (1); The two ends of the second spring (5) abut against the conductive retaining ring (31) and the insulating sleeve (6) respectively. The first spring (4) and the second spring (5) are both in a compressed state. The two ends of the conductive housing (1) are respectively fixed with an access line (11) connected to the movable electrode (3) and an output line (12) connected to the temperature sensor (2); characterized in that, The end of the outgoing line (12) near the conductive housing (1) is provided with a protrusion (121), and a fixing annular groove (1211) is provided on the outer peripheral surface of the protrusion (121). The end of the conductive housing (1) away from the incoming line (11) can be inserted into the fixing annular groove (1211).
2. The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system according to claim 1, characterized in that, When the temperature sensing body (2) melts, the second spring (5) can push the movable electrode (3) to move closer to the connection line (12). The first spring (4) can move as a whole closer to the connection line (12) under the push of the movable electrode (3). At this time, the end of the movable electrode (3) away from the conductive retaining ring (31) can be disconnected from the end of the access line (11) inserted into the conductive housing (1). The distance between the end of the movable electrode (3) away from the conductive retaining ring (31) and the end of the access line (11) inserted into the conductive housing (1) is not less than 8mm.
3. The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system according to claim 1, characterized in that, The conductive retaining ring (31) has a wear-resistant layer (311) on the side near the first spring (4).
4. The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system according to claim 1, characterized in that, The conductive retaining ring (31) has guide arc surfaces (312) on both sides near the inner wall of the conductive housing (1).
5. The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system according to claim 1, characterized in that, A sealing resin (7) extending to the middle of the outer periphery of the access line (11) is fixed on the middle of the outer periphery of the conductive housing (1).
6. The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system according to claim 5, characterized in that, The conductive housing (1) is provided with a sealing strip (8) on the outside. One end of the sealing strip (8) is fixedly connected to the outer peripheral surface of the sealing resin (7), and the other end is fixedly connected to the outer peripheral surface of the conductive housing (1).
7. The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system according to claim 6, characterized in that, The conductive housing (1) has a guide ring groove (13) on its outer peripheral surface, and the sealing resin (7) has a positioning ring groove (71) on its outer peripheral surface. The two ends of the sealing strip (8) can be respectively embedded in the guide ring groove (13) and the positioning ring groove (71).
8. The over-temperature protection fuse for a 1500V DC photovoltaic shutdown system according to claim 1, characterized in that, The conductive retaining ring (31) has a support ring groove (313) on its outer circumferential surface, and the insulating sleeve (6) has a limiting ring groove (61) at its end away from the access line (11); one end of the second spring (5) can be inserted into and fixed in the support ring groove (313), and the other end can be inserted into and fixed in the limiting ring groove (61).