WO2017041242A1

WO2017041242A1 - Reflowable temperature fuse

Info

Publication number: WO2017041242A1
Application number: PCT/CN2015/089236
Authority: WO
Inventors: 吴国臣; 王军
Original assignee: 上海长园维安电子线路保护有限公司
Priority date: 2015-09-09
Filing date: 2015-09-09
Publication date: 2017-03-16
Also published as: CN107077991A; CN107077991B

Abstract

A reflowable temperature fuse (100), comprising:a conductive element with a first end part (110) and a second end part (120), wherein a sensing element (180) is connected to the first end part (110) or the second end part (120) of the conductive element, and when a temperature exceeds a critical threshold value, softening or melting deformation occurs;a conductive elastic element (150) for applying a force to the conductive element and electrically connecting the conductive element by means of the action of an elastic force;an activation button (130) which is pressed down and applies a force to the elastic element (150) so as to enable the temperature fuse (100) to be in an activated state, and when a temperature surrounding the reflowable temperature fuse (100) exceeds a critical threshold value, the conductive element is disconnected via the elastic element (150);and two or more bonding pads forming an electrical connection to an external circuit, wherein at least a first bonding pad (141) and a second bonding pad (142) are respectively connected to the first end part (110) and the second end part (120) of the conductive element, and are arranged in an internal accommodating space formed by combining a cover cap (160) and a base (170).

Description

Reflowable thermal fuse

Technical field

The invention relates to a reflowable thermal fuse, belonging to a surface mount type electronic device, in particular to a push-activated reflowable thermal fuse.

Background technique

Circuit protection components are often used to protect power electronics, so that the circuits of these products can be protected from faulty current circuits in a timely manner. Many over-temperature or over-current protection devices are used in the circuit protection requirements of these products. This also brings security and reliability to power electronics. For example, this protection circuit can be used to protect against and avoid failure of the automotive engine control module, and even to prevent fires caused by power circuit failure.

A thermal fuse is a type of circuit protection component. The function of the thermal fuse is somewhat similar to a traditional glass tube fuse. Under normal operating conditions, the thermal fuse can be turned on at both ends of the fuse portion, and when the fault condition exceeds the critical temperature, the fusible portion of the thermal fuse is broken to form an open circuit. When the temperature is lower or higher than the critical temperature, the temperature fuse is switched between on and off. That is to say, due to overcurrent or adjacent component failure temperature rise, the temperature fuse will switch from the on state to the non-conducting or off state once the temperature reaches a certain critical temperature.

To facilitate this conversion, the thermal fuse must contain a conductive member, such as a wire, or a cap, or a tin-plated metal, or other phase-contacting metal that can be converted from a conducting state to a conductive state. Non-conducting or open state. The structure of the thermal fuse also includes a temperature sensing member. The physical state change of this temperature sensing member is related to its operating temperature. For example, the temperature sensing member can be composed of a low melting point metal or a discrete meltable organic compound that melts at a particular critical temperature. When the temperature sensing member melts to change its physical state, the conductive path of the thermal fuse can be disconnected to switch from the conductive state to the non-conductive or open state.

In actual operation, current flows through the fusible portion of the fuse. Once the temperature sensing member reaches a certain critical melting temperature, the thermal fuse can be switched from an on state to an open or non-conducting state. One disadvantage of existing thermal fuses is the thermal factor. Special care must be taken when assembling the board to prevent the temperature sensing member from reaching a melting temperature that changes its physical state. There is no such heat problem with conventional glass tube fuses, because the fuse holder is soldered in advance, and the fuse is inserted, and the fuse holder itself is not afraid of the peak or soldering heat. However, if the SMT technology is used to reflow the thermal fuse, special care must be taken to avoid the temperature sensing of the thermal fuse reaching the melting temperature that changes its physical state. As a result, the old thermal fuse cannot be reflowable because the temperature will exceed the specific critical melting temperature of the temperature sensing component during reflow soldering to the board, causing the thermal fuse to prematurely break from the conducting state. Open and cannot be used.

Temperature fuses are usually implemented in pin form and require special care and also Not suitable for reflow soldering, so reflowable thermal fuses are the result. In general, a thermal fuse includes a conductive element that carries a flow of electrical current, and an elastic element that is adapted to apply a force to the conductive element. In some embodiments, the conductive element incorporates a sensing element. When the temperature exceeds the sensing element threshold or melting temperature, the sensing element softens and loses its elasticity, making it susceptible to deformation or breakage by the force exerted by the elastic element on the conducting element. Eventually, the conductive element will be broken under mechanical force to cause an open circuit condition. The heat experienced during the reflow process may cause the sensing element to lose its elasticity and break. Therefore, it is contradictory that the sensing element is not disconnected during the reflow process, and the heat generated from the failure or overcurrent of the adjacent device must be disconnected from the sensing element. In order to overcome the above problems, a reflowable thermal fuse was developed.

Application No.: 201310112330.5 provides a thermal fuse that can be miniaturized by improving the sealing performance of a thermal fuse. The thermal fuse includes: a base film; a pair of strip-shaped terminal portions disposed on the base film so as to be spaced apart from each other at a tip end portion; and a meltable material that is bridged between the pair of terminal portions; a flux on the melt; and a cover film provided in a meltable manner covering the flux applied, at least in the length direction of the thermal fuse, at the inner edge and the outer edge of the package The ends are cut off, and the base film and the cover film on the cut surface are welded again.

U.S. Patent No. 8,289,122 and U.S. Patent No. 8,581,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, The elastic member is biased by the conductor to be disconnected during welding. The disadvantage of this design is that the step of energizing the disconnection must be performed after the reflow assembly to activate the thermal fuse, thus increasing the complexity of the OEM process.

Summary of the invention

SUMMARY OF THE INVENTION The object of the present invention is to provide a reflowable temperature fuse which does not require a suppressing member to prevent the fuse from being broken during reflow soldering, and does not need to pass a current to blow the suppressing member after the reflow soldering is completed.

The object of the present invention is achieved by the following scheme: a reflowable thermal fuse, which is a thermal fuse, comprising:

a conductive element comprising a first end and a second end;

a sensing element connected to one end of the conductive element for softening or melting deformation when the temperature exceeds a critical threshold;

An elastic component, composed of a conductive material, is applied to apply a force to the conductive component, and under normal conditions, electrically connect the conductive component according to the elastic force;

The activation button is used to apply force to the elastic member. When the thermal fuse is in the initial state, the activation button is not in contact with the elastic member; after the assembly is completed, the activation button is pressed and applied to the elastic member to activate the thermal fuse. State, and under fault conditions, the conductive element is broken by the elastic element;

Having a plurality of pads electrically connected to an external circuit, such as two or more, at least the first pad and the second pad are respectively connected to the two ends of the conductive member, and are disposed on the cover and the base to form an inner portion. In the accommodation space;

Wherein, the sensing element, when the temperature around the temperature fuse exceeds a critical threshold, the elastic force transmitted by the activation button pressing down to the elastic element causes the conductive element to be disconnected.

The invention realizes the activation of the thermal fuse through an activation button, which not only simplifies the process of the pad design and the assembly process, but also improves the reliability of the device.

The working principle of the invention is that the elastic element can exert a force on the conductive element in an activated state, and the elastic element applies a force to bond the conductive elements together in a normal state during reflow soldering assembly; The spring element employed in the prior art applies a conductive element that separates the force from the thermal fuse in the activated state. After reflow soldering, the activation button is pressed and a force is applied to the resilient member to bring the reflowable thermal fuse into an active state. The force applied to the resilient member by the activation button can be disconnected from the first and second ends of the conductive member when encountering, for example, a high temperature or overcurrent occurs or the adjacent device heats up due to a fault condition.

Based on the above solution, the elastic element is in the shape of a raised reed or arch, one end of which is fixedly connected to one end of the conductive element, and the other end is elastically abutted to the sensor, and is electrically connected to the end of the other conductive element through the sensor. connection.

Based on the above scheme, the sensing element is composed of solder or other metal alloy having a melting point between 70 ° C and 250 ° C.

Based on the above solution, the solder pad is fixed on the base, and the base is further configured to carry a conductive element, an elastic element and a sensing element electrically connected to the solder pad, and the base and the cover form an outer casing. The cover is used to insulate the outside and support the activation button.

Based on the above solution, the base is coupled to the cover via a hook, glue and/or ultrasonic welding.

Based on the above solution, the activation button supported on the cover is separately implanted, or extends along the inner groove of the cover via two arms or directly built inside the cover.

Based on the above solution, the activation button includes two positions of protrusions or indentations for fixing in two states, an assembled state and an activated state.

Based on the above solution, the solder pad is at least partially exposed to the outer casing and soldered to the PCB board or the panel.

In the above solution, the first end of the conductive element is electrically connected to the first pad; the second end is electrically connected to the second pad.

Based on the above solution, the first pad and the second pad extend the outer metal electrode.

If the high temperature fault condition causes melting of the sensor element, this breaks the connection between the first end and the second end of the resilient conductive element and thus disconnects the connection between the first pad and the second pad .

After reflow soldering, the activation button can be pressed via a thumb or tool or some mechanical operation, thus eliminating the need for an operational step similar to the previous use of current to blow the suppression element.

The present invention is advantageous in that the assembly process of the reflow type thermal fuse can be effectively simplified, and the reliability of the product is also improved.

DRAWINGS

Figure 1 is a cross-sectional view of the reflowable thermal fuse of the first embodiment of the present invention in an assembled state (before activation);

Figure 2 is a cross-sectional view of the reflowable thermal fuse of the first embodiment of the present invention in an activated state (after pressing the activation button);

Figure 3 is a cross-sectional view showing the reversibly solderable temperature fuse of the first embodiment of the present invention in a state in which the elastic member is disconnected under a fault condition;

Figure 4 is a flow chart of the reflowable thermal fuse assembled on the PCB and pressing the activation button to activate the reflowable thermal fuse;

Figure 5 is a view showing the use of an activation button and an elastic member block in the reflowable thermal fuse of the first embodiment of the present invention and the breaking of the elastic member under a fault condition;

Figure 6 is a cross-sectional view showing the base of the reflowable thermal fuse of the second embodiment of the present invention;

Figure 7 is an explanatory view showing a layered structure of a reflowable temperature fuse according to a second embodiment of the present invention;

Figure 8 is a cross-sectional view showing the reversibly solderable temperature fuse of the third embodiment of the present invention in a state in which the elastic member is disconnected under a fault condition, the distance at which the activation button is pressed is far from the connection position of the sensing member, and the breaking distance of the elastic member is Also longer;

Figure 9 is a cross-sectional view of a reflowable thermal fuse of a fourth embodiment of the present invention with an activation button extending from the two arms for advancement along the inner wall groove, wherein Figures 9a, 9b and 9c are activation button portions, respectively FIG. 9aA-A is a schematic cross-sectional view of the AA of FIG. 9a in a state in which it is inactivated, activated, but the elastic member is not deformed, and activated and the elastic member is deformed;

Figure 10 is a perspective exploded structural view of a reflowable thermal fuse according to a fourth embodiment of the present invention;

Figure 11 is a cross-sectional view of a reflowable thermal fuse according to a fifth embodiment of the present invention, wherein Figures 11a, 11b, and 11c are respectively activated, activated, but the elastic member is not deformed or deformed, and A schematic diagram of a state in which the elastic member is deformed to an open circuit;

Figure 12 is a perspective exploded perspective view of a reflowable thermal fuse according to a fifth embodiment of the present invention.

detailed description

The reflowable thermal fuses are further described in detail below with reference to the accompanying drawings. However, the specific embodiments are merely illustrative of specific products and methods of manufacture, and how to use the invention, but are not intended to limit the scope of the invention.

Example 1

1 is a cross-sectional view showing the reflowable thermal fuse of the first embodiment of the present invention in an assembled state. A reflowable thermal fuse 100 includes a first end 110 and a second end 120 of a conductive element; a sensing element 180 coupled to the first end 110 of the conductive element that occurs when the temperature exceeds a critical threshold Softening or melting deformation; an elastic member 150, composed of a conductive material, is applied to the conductive member, and under normal conditions, the conductive member is electrically connected according to the elastic force; an activation button 130 is used to apply force to the elastic member, In the initial state of the thermal fuse, the activation button 130 is not in contact with the elastic member 150. After the assembly is completed, the activation button 130 is pressed and applied to the elastic member 150 to activate the thermal fuse and under the fault condition. Disconnecting the conductive member by the elastic member 150; the first and

second pads

141, 142 having electrical connection with the external circuit are electrically connected to the first end portion 110 and the second end portion 120 of the conductive member, respectively; The sensing element 180, when the temperature around the temperature fuse exceeds a critical threshold, the elastic force transmitted by the activation button 130 to the elastic member 150 causes the conductive element to be broken. . The elastic member 150 is fixedly connected to the second end portion 120 of the conductive member at one end, and the other end is elastically abutted against the sensor 180, and is electrically connected to the first end portion 110 of the conductive member via the sensor 180. Sensing element 180 can be made of a conductive material that has a relatively low melting point or that loses its elasticity at a particular temperature. For example solder, or alloy metal. The solderable thermal fuse 100 further includes a cover 160 and a base 170. The first and

second pads

141, 142 are fixed on the base, and the base 170 and the cover 160 form an outer casing. The outer button is insulated from the outside and supports an activation button 130 that also carries the conductive member first end 110 and second end 120, the resilient member 150 and the sensing member 180 that are electrically coupled to the pads. The susceptor 170 can be made via an injection molding or PCB process. The base 170 can be coupled to the cover 160 via a hook, glue, and/or ultrasonic weld. The activation button 130 supported on the cover 160 is separately implanted, and the activation button 130 includes protrusions or indentations at two positions for fixing in two states, an assembled state and an activated state. In the following embodiments, the first and second ends 110, 120 of the conductive element and the elastic element 150 can also be disposed on the base or the circuit board accordingly. The first and

second pads

141, 142 can be used to solder the reflowable thermal fuse 100 to a PCB board or panel (not shown), which also includes the first and second ends 110, 120 of the conductive element. It is connected to the outside of the cover 160 to be connected to the circuit, and can extend the external metal electrode. In the actual operation of the reflowable thermal fuse, the load current flows through the first and second ends 110, 120 of the conductive element. For example, the load current can be generated by the power supply and flow through the conductive element to other circuits. The elastic member 150 may be made of a conductive material such as copper, nickel, stainless steel or other metals. Other materials or structures may be used as long as they are capable of exerting a force on the conductive member. In this embodiment, the elastic member 150 It is the same component as the second end portion 120 of the conductive member, and has both electrical conductivity and the function of applying force.

2 is a cross-sectional view showing the reflowable thermal fuse of the first embodiment of the present invention in an activated state, after the reflow soldering, the activation button 130 is pressed so that the reflowable thermal fuse 100 is in an activated state. . This activation button 130 exerts a force on the resilient member 150 while the resulting internal stress is transmitted to the sensing member 180 to create a separate force which activates the reflowable thermal fuse 100.

3 is a cross-sectional view showing the state in which the elastic element of the reflowable temperature fuse of the first embodiment of the present invention is disconnected under a fault condition, in which state the reflowable thermal fuse 100 has been previously pressed with the activation button 130. , is in the active state, as shown in Figure 2 above. When the ambient temperature around the reflowable thermal fuse 100 reaches a critical temperature, such as 200 ° C, the sensing element 180 loses its elasticity and/or becomes susceptible to deformation or melting. When this occurs, the force transmitted by the resilient element 150 to the sensing element 180 causes the sensing element 180 to open, thereby preventing current from flowing through the sensing element 180, and the conductive element is first disconnected from the circuit. The two ends 110, 120 also break the first and

second pads

141, 142.

Figure 4 shows a flow chart of the reflowable thermal fuse assembled on the PCB and pressing the activation button to activate the reflowable thermal fuse. In the process block, the reflowable thermal fuse is placed on a PCB board or panel and passed through a reflow oven. For example, the reflowable thermal fuse 100 of FIG. 1 is placed on a PCB board or panel during the assembly phase. On, then through the reflow oven. Solder is pre-coated through stencil to the appropriate position of the reflowable thermal fuse 100 pad on the PCB or panel. Place a reflowable thermal fuse and then pass the reflow oven to melt and cool the solder on the pad. In the flow block, the activation button 130 on the reflowable thermal fuse 100 of FIG. 2 can be depressed such that in the process block, the reflowable thermal fuse 100 is in an active state. This activation button 130 exerts a force on the resilient member 150 while the resulting internal stress is transmitted to the sensing member 180 to create a separate force that completes activation of the reflowable thermal fuse 100. Referring to FIG. 2 above, in the next application, if too much heat is loaded into the reflowable thermal fuse 100, the sensing element 180 is pressed and the force is transmitted to the elastic element 150. Under the force generated, it loses its elasticity and becomes easily deformed and broken. As can be seen from the above description, the reflowable thermal fuse 100 of the present invention overcomes the problems encountered by the old thermal fuses in the surface mount process through reflow soldering. The innovative concept of the activation button makes the reflowable thermal fuse 100 easy to activate, and the conductive components are broken under subsequent fault conditions.

Figure 5 is a conceptual diagram showing the use of an activation button and an elastic member block and the breaking of the elastic member under a fault condition in the reflowable thermal fuse of the first embodiment of the present invention. In the schematic view of Fig. 5, the elastic member 150 is Designed to be used in the shape of an arch, and it can also be used as the second end 120 of the conductive element carrying the working current. The rear end of the second end 120 of the conductive element also includes the sensing element 180, which is the same as the conductive element. It receives the elastic force from the elastic member 150. In normal assembly state, this The spring force bonds the second end portion 120 of the conductive member to the first end portion 110. The activation button 130 can here provide a force to activate the reflowable thermal fuse 100. When the activation button 130 is depressed, the reflowable thermal fuse 100 has been activated, but the conductive element first and second ends 110, 120 and the sensing element 180 are still joined together. In the event of a subsequent fault condition or overheating, the sensing element 180 loses its elasticity and either becomes susceptible to deformation and or breaks, losing the ability to bond the first and second ends 110, 120 of the conductive element together. The disconnection is shown in the broken line portion shown in FIG.

The present invention proposes an innovative concept of an activation button that can simultaneously accomplish the assembly process and the activation state. During the assembly process, the direction of the stress generated by the elastic elements tends to cause the conductive elements to tend to bond together.

After the reflowable thermal fuse is mounted on the PCB or panel through the reflow oven, the activation button can be pressed down, applying force to the resilient member. This step activates the reflowable thermal fuse.

Example 2

Figure 6 is a cross-sectional view showing the base of the reflowable thermal fuse of the second embodiment of the present invention. In the structural view of this embodiment, the elastic member 250 is formed into an upwardly curved reed shape prior to manufacture, and the remaining structure is identical to that of Embodiment 1, so that when it is bent under the first end portion 210 of the conductive member, the elasticity Element 250 applies a force to weld conductive element first end 210, sensing element 280 together during reflow soldering.

Fig. 7 is a view showing a layered structure of a reflowable temperature fuse according to a second embodiment of the present invention. The activation button 230, the cover 260, respectively, carries the first and second ends 210, 220 of the conductive element, the elastic element 250, and the base of the sensing element 280.

Example 3

Figure 8 is a cross-sectional view showing the state in which the elastic member of the reflowable temperature fuse of the third embodiment of the present invention is disconnected under a fault condition. In the fault condition, the activation button 330 of the reflowable thermal fuse 300 has been previously pressed in an active state, as described in FIG. In this embodiment, the depression of the activation button 330 is far from the position of the first end 310 of the conductive member, so the end of the elastic member 350 is also longer, and can withstand higher operating voltage without arcing. When the ambient temperature around the reflowable thermal fuse 300 reaches a critical temperature, such as 200 ° C, the sensing element 380 loses its elasticity and/or becomes susceptible to deformation or melting. When this occurs, the force transmitted by the resilient element 350 to the sensing element 380 causes the sensing element 380 to open, thereby preventing current from flowing through the sensing element 380, ie, breaking the first and second ends of the conductive element. 310, 320, that is, the first and

second pads

341, 342 on the base 370 are disconnected.

Example 4

Figure 9 is a cross-sectional view showing a reflowable thermal fuse of a fourth embodiment of the present invention, in which the activation button 430 extends from the two arms to advance along the inner wall groove. To help activate button 430 Move more smoothly and calmly. The activation button 430, the cover 460, the first and second ends 410, 420 of the conductive elements, the resilient member 450, and the base of the sensing element 480 are shown, respectively. Figure 9a shows the state of the reflowable thermal fuse in the assembly phase, the activation button 430 is not depressed down to the active state, as shown in Figures 9aA-A, the activation button 430 does not abut the resilient member 450; in Figure 9b The activation button 430 is pressed so that the reflowable thermal fuse 400 is in an active state, but the sensing element 480 is not deformed greatly, and the circuit is still in an on state; and in FIG. 9c, in a fault state or beyond The heat causes the sensing element 480 to break or deform, causing the circuit to open.

10 is a perspective exploded perspective view showing a reflowable thermal fuse according to a fourth embodiment of the present invention, wherein the activation button 430, the cover 460, and the first end portion, the

second end portion

410, 420 carrying the conductive member are elastic. Element 450, the base of sensing element 480.

Example 5

Figure 11 is a cross-sectional view showing a reflowable thermal fuse of a fifth embodiment of the present invention. The cover 560 and the activation button 530, which is integral with the cover 560, respectively, includes a conductive element first and

second end portions

510, 520, an elastic member 550, and a base of the sensing member 580. In Figure 11a, the state of the reflowable thermal fuse is shown in the assembly phase; in Figure 11b, the activation button 530 is depressed to cause the reflowable thermal fuse 500 to be in an active state; and in Figure 11c, The fault condition or excess heat causes the sensing element 580 to open the connection to the circuit. In the present embodiment, the activation button 530 is fixed in the cover 560. Therefore, after the reflow assembly is assembled, the action of pressing the cover 560 is equivalent to pressing the activation button 530 and causing the reflowable thermal fuse 500 to be activated.

Fig. 12 is a perspective exploded perspective view showing the reflowable thermal fuse of the fifth embodiment of the present invention. The reflowable thermal fuse 500 includes a cover 560 and a base carrying the first and second ends 510, 520 of the conductive elements, the resilient member 550, and the sensing member 580. The activation button 530 is here located within the cover 560 and is therefore not shown in the figures.

Based on the description of the various embodiments above, the activation button can be implemented in various design forms as long as it can apply a mechanical force on the elastic member. After the reflow soldering temperature fuse is assembled, the activation button is pressed and the reflowable temperature insurance is activated. Unlike conventional reflowable thermal fuses, which must pass current to blow the limiting element, the simple mechanical design of the present invention can easily activate the thermal fuse, thereby increasing the reliability of the device and simplifying the process to reduce production costs.

The above is only the disclosure of the embodiment of the present invention relating to the reflowable thermal fuse, and is not intended to limit the scope of the invention. Different methods are also contemplated by the present invention where mechanical forces can be used to join the elastic members together, and after the flow welding assembly can be applied to the elastic members by mechanical force to allow the reflowable temperature insurance to be activated.

Claims

A reflowable thermal fuse containing:

a conductive element comprising a first end and a second end;

a sensing element connected to one end of the conductive element for softening or melting deformation when the temperature exceeds a critical threshold;

An elastic component, composed of a conductive material, is applied to apply a force to the conductive component, and under normal conditions, electrically connect the conductive component according to the elastic force;

The activation button is used to apply force to the elastic member. When the thermal fuse is in the initial state, the activation button is not in contact with the elastic member; after the assembly is completed, the activation button is pressed and applied to the elastic member to activate the thermal fuse. State, and under fault conditions, the conductive element is broken by the elastic element;

Having two or more pads electrically connected to the external circuit, at least the first pad and the second pad are respectively connected to the two ends of the conductive element, and the cover is combined with the base to form an internal receiving space. Inside;

Wherein, the sensing element, when the temperature around the temperature fuse exceeds a critical threshold, the elastic force transmitted by the activation button pressing down to the elastic element causes the conductive element to be disconnected.
The reflowable thermal fuse according to claim 1, wherein said elastic member is in the shape of a raised reed or arch, one end of which is fixedly connected to one end of the conductive member, and the other end is elastically abutted from the sensor. The sensor is electrically connected to the end of the other conductive element.
A reflowable thermal fuse according to claim 1 or 2, wherein said sensing element is comprised of solder or other metal alloy having a melting point between 70 ° C and 250 ° C.
The reflowable thermal fuse according to claim 1, wherein the solder pad is fixed on the base, and the base and the cover form an outer casing, and the cover is insulated from the outside and supports an activation button. The pedestal is also used to carry conductive elements, elastic elements, and sensing elements that are electrically connected to the pads.
A reflowable thermal fuse according to claim 4 wherein said base is coupled to the cover via a hook, glue and/or ultrasonic weld.
The reflowable thermal fuse according to claim 4, wherein the activation button supported on the cover is separately implanted or extended along the inner groove of the cover via two arms or directly built in Inside the cover.
The reflowable thermal fuse according to claim 6, wherein the activation button comprises a projection or indentation at two positions for fixing in two states, an assembled state and an activated state.
The reflowable thermal fuse of claim 4 wherein said pad is at least partially exposed to the outer casing and soldered to the PCB or panel.
A reflowable thermal fuse according to claim 1 or 2, wherein said conductive member The first end is electrically connected to the first pad; the second end is electrically connected to the second pad.
The reflowable thermal fuse of claim 9 wherein said first pad and said second pad extend an outer metal electrode.