Switch with Pyrotechnic Actuator

Abstract

A switch for opening a current conduction path is provided. The switch includes an ignition chamber and a pyrotechnic actuator arranged to release gas into the ignition chamber upon ignition. The switch includes a first conductor and a second conductor, each of the first conductor and the second conductor including a connection contact. In a first position, a third movable conductor of the switch is disposed between the first conductor and the second conductor and is in electrical and physical contact with the first conductor and the second conductor to define a current conduction path; in a second position, the third conductor is arranged to be electrically and physically separated from the first conductor and the second conductor. The third conductor is movable in a direction from the first position towards the second position in response to actuation of the pyrotechnic actuator. The switch includes at least one releasable (optionally shearable) retaining member arranged to hold the third conductor in the first position until actuation of the pyrotechnic actuator. A vehicle including the switch and a method of operating the switch are also provided.

Description

Technical Field

[0001] The present invention relates to opening or interrupting an electric current conduction path. In particular, the present invention relates to a switch including a pyrotechnic actuator for opening the electric current conduction path, and a method for operating a switch involving ignition of the pyrotechnic actuator. Background Art

[0002] An electric current conduction path can be opened by disconnecting a continuous conductor defining the electric current conduction path. One way is to use a pyrotechnic-based switch to disconnect the continuous conductor.

[0003] There is a desire to provide an improved device for opening an electric current conduction path. This improved device is desirable for applications that require reliable and rapid opening of an electric current conduction path, such as a battery in an electric vehicle or an electrical overload mechanism for an industrial process. Summary of the Invention

[0004] In a first aspect, a switch is provided. In a second aspect, a method for operating the switch of the first aspect is provided.

[0005] In the following description, a switch for opening an electric current conduction path is described. The switch includes: an ignition chamber; a pyrotechnic actuator arranged to release gas into the ignition chamber upon ignition; a first conductor and a second conductor, the first conductor and the second conductor including connecting contacts; and a third conductor capable of moving in a direction from a first position towards a second position upon actuation of the pyrotechnic actuator (i.e., in response to actuation of the pyrotechnic actuator). The switch includes at least one disconnectable holding member arranged to hold the third conductor in the first position before actuation of the pyrotechnic actuator (i.e., until actuation of the pyrotechnic actuator); the holding member is arranged to disconnect depending on actuation of the pyrotechnic actuator to allow movement of the third conductor. In the first position, the third conductor is arranged between the first conductor and the second conductor and is in electrical contact and physical contact with the first conductor and the second conductor to define an electric current conduction path; in the second position, the third conductor is electrically and physically separated from the first conductor and the second conductor.

[0006] Prior pyrotechnic-based switches (or pyrotechnic-based circuit breakers) have relied on linear arrangements to disconnect single or continuous conductors. For example, the linear displacement of a pyrotechnically actuated piston will cut a conductor into two sections under a wedging action to interrupt current. This arrangement may be suitable for some low-current applications. However, for higher-current applications, the conductors to be disconnected are typically thicker or wider and thus require a higher force to disconnect the conductor. Such switches thus typically utilize larger pyrotechnic actuators, which results in an expensive and bulky switch arrangement. By using three separate conductor sheets that only engage a temporary joint provided by pushing a third conductor against the first and second conductors, a significantly smaller force is required to disconnect the electrical contact of the different conductors and open the current conduction path. This can result in a smaller and less expensive switch suitable for a range of current loads.

[0007] Specifically, by holding the third movable conductor in a first position with a disconnectable holding member, sufficient force can be applied to the third conductor to ensure the maintenance of electrical contact between the first, second, and third conductors, while facilitating the rapid and easy opening of the current conduction path once the pyrotechnic actuator is actuated by the disconnection of the disconnectable holding member (and thus by the subsequent movement of the third conductor to disconnect the temporary conductor joint). Since no mechanism is required to hold the third conductor in a position other than the disconnectable holding member and no permanent conductor joint (or continuous conductor) needs to be disconnected, less force is required and a smaller pyrotechnic actuator can be used, thus facilitating the provision of a smaller and less expensive switch.

[0008] Separating different conductors in the manner described herein can also help reduce the arcing (or arc discharge) that forms when the different conductors are separated from each other. Specifically, the movable third conductor can rapidly stretch the arc in response to actuation of its movement relative to the first and second conductors (i.e., the linear translation of the third conductor), thereby increasing the arc resistance. The increased arc resistance causes a corresponding increase in the arc voltage and a decrease in the arc current (since the arc exhibits a negative resistance). In the case of physical separation between the conductors achievable with the switches of the first aspect, the arc resistance can rapidly increase over time and the current correspondingly decreases to a value where the heat generated by the current passing through the air is not sufficient to sustain the arc, and the arc thus extinguishes. Therefore, a more effective interruption of the arc can be provided. A safer and more robust switch can thus be provided.

[0009] Optionally, the switch further includes an arc quenching medium disposed to be positioned between the first conductor and the second conductor when the third conductor is in the second position. The presence of the arc quenching medium can increase the interruption of the electric arc, thus helping to provide a safer switch. In some arrangements, the switch further includes an arc quenching medium element coupled to the third conductor; the arc quenching medium element is arranged to move into a position between the first conductor and the second conductor when the third conductor moves towards the second position. In other arrangements, a reservoir of the arc quenching medium is optionally provided inside the ignition chamber or outside the ignition chamber but between the pyrotechnic actuator and the third conductor; the arc quenching medium is arranged to be pushed between the first conductor and the second conductor by the actuation of the pyrotechnic actuator when the third conductor moves from the first position to the second position. Optionally, the arc quenching medium includes silica and can be provided in any suitable form, such as a liquid, powder or other solid form, or a thick viscous semi-solid liquid.

[0010] Optionally, the contact surfaces where the first conductor contacts the third conductor and the second conductor contacts the third conductor generally extend perpendicular to the moving direction of the third conductor. This can improve the electrical contact between the conductors. As used herein, generally perpendicular means approximately 90 degrees, optionally up to and including ±45 degrees. Optionally, the retaining member and the pyrotechnic actuator are arranged on opposite sides of the third conductor; this can provide a switch that is easier to assemble. Optionally, the releasable retaining member is arranged to apply a force in a direction generally opposite to the moving direction of the third conductor to retain the third conductor. Specifically, when the third conductor is provided as described above, this arrangement can apply a more efficient retaining force on the third conductor, thus improving the electrical contact.

[0011] Optionally, the pyrotechnic actuator is arranged to release gas into the ignition chamber in a direction generally parallel to the moving direction of the third conductor to actuate the third conductor. This arrangement can provide the most efficient energy transfer between the pyrotechnic actuator and the third conductor. As used herein, generally parallel means approximately 0 degrees, optionally up to and including ±45 degrees.

[0012] Optionally, a piston is disposed between the third conductor and the pyrotechnic actuation, and the piston includes a void that at least partially defines the ignition chamber. The actuating force from the pyrotechnic actuator is transmitted to the third conductor through the piston. When the ignition chamber is at least partially defined by the void in the piston, a smaller ignition chamber can be provided (initially at least, it should be understood that as the piston moves, the ignition chamber will expand in size). Therefore, less explosive may be required to generate the required pressure on the piston, which can provide a more efficient switch. Alternatively, the third conductor can be directly actuated by the pyrotechnic actuator.

[0013] Optionally, the switch further includes a housing arranged to enclose the third conductor and at least a portion of each of the first and second conductors, and optionally encloses the ignition chamber. Optionally, the housing may enclose at least a portion of the pyrotechnic actuator. The housing is arranged to support the separable retaining member. This structural support of the separable retaining member helps to apply sufficient force efficiently to the third conductor to hold the third conductor in the first position until the pyrotechnic actuator is actuated and the retaining member disconnects. Using this configuration, assembly and manufacturing can also be easier and more efficient.

[0014] Optionally, the retaining member is arranged to shear upon actuation of the pyrotechnic actuator, thereby allowing movement of the third conductor. The shearing of the retaining member can be provided by form and / or material. Optionally, the retaining member is at least partially formed of plastic; that is, at least the portion of the separable retaining member arranged to shear can be made of plastic. Plastic can be lightweight, inexpensive, and easy to form, and is thus well-suited as the sacrificial portion; thus, a less expensive switch applicable to a range of current loads can be provided. Alternatively, the separable retaining member can be made of any brittle material.

[0015] Optionally, the (shearable) retaining member includes: a support element configured to hold the third conductor portion against the first and second conductor portions prior to actuation of the pyrotechnic actuator; and a shearable portion arranged to shear around the support element upon actuation of the pyrotechnic actuator. Optionally, the support element includes a threaded portion and a threaded element configured to engage the threaded portion, the threaded element configured to hold the third conductor portion against the first and second conductor portions prior to actuation of the pyrotechnic actuator. The use of the threaded element can help to adjust the force provided to the third conductor, which can easily and simply account for any manufacturing tolerances and improve the utility of the switch. Additionally, the switch can be assembled more quickly and easily, thus improving manufacturing.

[0016] A system is provided that includes a switch and a controller as described above, the controller arranged to provide a signal to the pyrotechnic actuator to ignite the pyrotechnic actuator. This system can be used in any suitable application where a switch (or an automatic circuit breaker where an activation trigger is provided) is needed, such as for overload in industrial applications.

[0017] A vehicle is provided that includes a switch as described above. Optionally, the vehicle may further include a controller arranged to provide a signal to the pyrotechnic actuator to ignite the pyrotechnic actuator. Optionally, the vehicle is an electric vehicle. The switch can be used, for example, to disconnect a circuit in the vehicle's battery in the event of an accident. This can improve safety.

[0018] In the following description, a method for operating a switch is described. The method is optionally a method for operating a switch of a first aspect. The method includes: igniting a pyrotechnic actuator; releasing gas into an ignition chamber by ignition; applying pressure to a third movable conductor held in a first position within the ignition chamber by a disconnectable retaining member, depending on the released gas; wherein in the first position, the third conductor is arranged between a first conductor and a second conductor and is in electrical and physical contact with the first conductor and the second conductor to define a current conduction path; disconnecting the retaining member and moving (or displacing) the third conductor from the first position and towards a second position by (i.e., in response to) the applied pressure, wherein in the second position, the third conductor is electrically and physically separated from the first conductor and the second conductor; and opening the current conduction path of the conductors by the displacement of the third conductor. Optionally, the third conductor is arranged within the ignition chamber. Optionally, pressure is applied to the third conductor by means of a piston, the piston including a void that at least partially defines the ignition chamber.

[0019] It will be understood that any of the features described above in reference to the switch of the first aspect may be provided in any suitable combination. Additionally, where appropriate, any such feature may be combined with any feature of the method of the second aspect, or vice versa. Description of the Drawings

[0020] The following description refers to the following figures:

[0021] Figure 1: Figure 1A Shows a schematic cross-section (A-A) of a switch according to an embodiment of the first aspect, where the switch is in a first closed position, and Figure 1B Shows Figure 1A a schematic cross-section (A-A) of the switch, where the switch is in a second open position;

[0022] Figure 2: Figure 2A Shows Figure 1A a perspective view of the switch, Figure 2B shows a perspective view of the switch in an intermediate position between closed and open, and Figure 2C shows Figure 1B a perspective view of the switch;

[0023] Figure 3: Figure 3A Illustrates elements of a disconnectable retaining member according to an embodiment of the first aspect, and Figure 3B illustrates a disconnectable retaining member Figure 1A without a threaded element;

[0024] Figure 4Planar view (upper left), schematic cross-section (B-B) (lower left), and perspective view (right) of the shearable portion of the disconnectable holding member of FIG. 3;

[0025] Figure 5 Description Figure 1A exploded perspective view of the switch of;

[0026] Figure 6 Description of a vehicle including the switch of the first aspect; and

[0027] Figure 7 Description of a method according to the second aspect. Detailed Description

[0028] Referring to FIGS. 1 ( Figure 1A and 1B ) and FIGS. 2 ( Figure 2A , 2B and 2C), a switch 100 for opening a current conduction path is described. The current conduction path is defined by a first conductor 106, a second conductor 108, and a third conductor 110. These conductors are separate components arranged to define the current conduction path by means of a temporary joint between the first conductor 106, the second conductor 108, and the third conductor 110.

[0029] The switch 100 includes a housing 114 arranged to enclose at least a portion of the third conductor and each of the first conductor 106 and the second conductor 108. Here, the first conductor 106 and the second conductor 108 include connection contacts 106a, 108a, which are provided outside the housing 114 for connecting the switch 100 to one or more circuits.

[0030] The temporary joint is provided by means of a disconnectable holding member 112 (shown within the dashed box in FIG. 1), which is arranged to hold the third conductor 110 in direct electrical and physical contact with the first conductor 106 and the second conductor 108 to define the current conduction path. The contact surfaces where the first conductor 106 contacts the third conductor 110 and the second conductor 108 contacts the third conductor 110 may extend generally parallel to each other to facilitate this direct electrical and physical contact.

[0031] The separable retaining member (or retaining member) 112 can be separated by material and / or form. In the arrangement described with reference to FIGS. 1 and 2, the retaining member 112 is mainly separable by form due to the introduction of mechanical weaknesses within the retaining member 112. The retaining member 112 can be conductive or electrically insulating; however, the retaining member 112 can be electrically isolated from the third conductor 110 in order to maintain good electrical contact between the first conductor 106, the second conductor 108, and the third conductor 110. At least one separable retaining member 112 can be provided; for example, one retaining member can be present as needed, or multiple retaining members (two, three, four, or more).

[0032] When the switch is in operation, the retaining member 112 holds the third conductor 110 by exerting or applying a force in a direction generally opposite to the direction of movement of the third conductor 110; the reaction force between the retaining member 112 and the part of the switch housing 114 that supports the retaining member is used to resist the movement of the third conductor until an actuating force greater than the force supplied by the retaining member 112 is applied. Specifically, the retaining member 112 is held in a fixed position by the housing 114, that is, rigidly fixed or fastened to the housing; in this way, the third conductor 110 can be held in the first closed position by the retaining member 112 and can thus withstand relatively large vibrations from the environment in which it is deployed without opening the switch (provided that the vibrations are not so large as to cause the separable retaining member 112 to separate). This can improve the resilience and utility of the switch 100.

[0033] Here, the actuating force is provided by a pyrotechnic actuator 102 arranged to release gas into the ignition chamber 104 upon ignition. The pyrotechnic actuator 102 includes a connector pin 102a and an igniter 102b. Upon receiving an ignition signal, the connector pin 102a activates the charge inside the igniter 102b. The pyrotechnic actuator 102 is arranged to expel gas into the ignition chamber 104 when the charge is activated or ignited. In this arrangement, the switch includes a piston 120, and the piston 120 includes a void that defines the ignition chamber. However, it should be understood that the piston may not be provided within the switch, and the ignition chamber can be defined in other ways (for example, it can be defined by a void provided within the housing).

[0034] The high-pressure gas expelled into the ignition chamber 104 generates an actuating force acting on the third conductor 110 such that the third conductor moves in the direction of movement 130 from a first position ( Figure 1A and 2A as shown in) towards a second position ( Figure 1B and 2C as shown in). The intermediate position is shown in Figure 2BInside. The pyrotechnic actuator is arranged to release gas into the ignition chamber in a direction generally parallel to the direction of movement 130 of the third conductor to actuate the third conductor. In this arrangement, the force acts on the third conductor 110 via the piston 120, but it should be understood that the force can act directly on the third conductor 110, or act on the third conductor 110 via any other suitable component provided between the pyrotechnic actuator 102 and the third conductor 110. When the third conductor is in the first position, the switch is closed, and when the third conductor is in the second position, the switch is open. In the second open position, the third conductor is electrically separated from the first and second conductors such that no current can flow through the current conduction path.

[0035] The disconnection of the temporary joint between the first, second, and third conductors and the subsequent opening of the current path can cause the formation of an arc between the end of the third conductor 110 and the corresponding ends of the first conductor 106 and the second conductor 108. This phenomenon can occur as long as the conductors are physically separated from each other. The linear displacement of the third conductor relative to the first and second conductors can help reduce this arc (or arc discharge) by rapidly stretching the arc, thereby increasing the arc resistance. The increased arc resistance causes a corresponding increase in the arc voltage and a decrease in the arc current (since the arc exhibits a negative resistance). Due to the dynamic nature of the force applied by the pyrotechnic actuator and the fact that the conductors do not need to be physically disconnected in any way, the speed of the displacement that occurs can be used to more rapidly increase the physical separation of the corresponding conductors than previous linear methods, thereby causing a more effective interruption of the arc. A safer and more robust switch can be provided.

[0036] The arc interruption or extinction can be further improved by using an arc quenching medium. In this arrangement, a reservoir of the arc quenching medium 116 can be arranged in the void around the piston 120, as Figure 1A illustrated. When the third conductor is displaced upon actuation of the pyrotechnic actuator 102 (i.e., in response to the actuation of the pyrotechnic actuator 102), the arc quenching medium 116 is correspondingly displaced to fill the gap vacated by the third conductor 110; this displacement can be caused by the high-pressure gas emitted by the pyrotechnic actuator 102 or can be caused by the piston 120 when the piston is disposed within the switch. Alternatively, in other sets of embodiments, an arc quenching medium element can be provided that is coupled to the third conductor 110 and is arranged to move into the gap vacated by the third conductor 110 when the third conductor moves. It should be understood that the arc quenching medium can be provided in any other suitable arrangement to assist in the interruption or extinction of the arc. In this set of embodiments, the arc quenching medium 116 includes silica. The silica medium can be provided in any suitable form, such as a liquid, powder, or other solid, or as a thick viscous semi-solid liquid. However, it should be understood that the arc quenching medium 116 can include silica in any suitable form. Alternatively, any other suitable arc quenching medium can be used.

[0037] Refer to FIG. 3 ( Figure 3A and 3B ), the illustrative disconnectable retaining member (or retaining member) 112 is described. Prior to actuation of the pyrotechnic actuator 102, the retaining member 112 (shown within the dashed box) is supported by the housing 114, i.e., rigidly held in a fixed position within the switch 100 by the housing 114. The retaining member 112 is arranged to apply a force on the third conductor 110 in the direction 132 to maintain physical and electrical contact between the third conductor and the first conductor 106 and the second conductor 108, the direction being generally opposite to the direction of movement 130 of the third conductor 110. As used herein, generally parallel means approximately 0 degrees, optionally up to and including ±45 degrees.

[0038] The retaining member 112 of this group of embodiments includes a "shear insert" 310 (shown within the small dashed box). The shear insert 310 is a sacrificial part that is inserted within the housing 114 and supported by the housing 114, and is arranged to shear in response to the actuating force from the pyrotechnic actuator 102. The shearing of the shear insert 310 can be caused by one or more mechanical weaknesses within the shear insert 310, such as caused by the geometry of the component, and / or as a result of the material selection.

[0039] The shear insert 310 described herein includes a shearable portion 312 that is arranged around a support element 314 (shown within the large dashed box). The shearable portion 312 includes a groove that introduces a mechanical weakness into the shear insert 310 due to a reduction in material thickness. The shear insert is also at least partially formed of plastic to assist in shearing. Additionally, plastic is lightweight and inexpensive, thus helping to provide a lighter and less expensive switch. However, any suitable material and / or structure for the retaining member 112 can be used to provide a component that is capable of applying sufficient force to hold the third conductor 110 in the first position until actuation of the pyrotechnic actuator 102, but is also capable of easily shearing under the actuating force caused by the high-pressure gas generated by the actuator 102. For example, any brittle material can be used to form the shearable portion 312 of the disconnectable retaining member 112.

[0040] The support element 314 is arranged to hold the third conductor 110 by optionally applying a force on the third conductor 110 in the direction 132. In this group of embodiments, the support element 314 includes a threaded portion 316 of the shear insert that is arranged to receive a threaded element. The support element also includes a threaded element 320 that is arranged to engage the threaded portion 316. In this example, the threaded element 320 is a flat head screw, but any other suitable threaded element, such as a bolt or other screw, can be used.

[0041] The use of the threaded portion 316 and the threaded element 320 can help provide an adjustable force to the third conductor 110, which can help ensure good contact between the third conductor 110 and the first conductor 106 and the second conductor 108. This can improve the utility of the switch 100. However, in some embodiments, a solid non-adjustable support element 314 may be provided instead. In other embodiments, the support element may be formed by an elastic element (elastic through structure and form and / or through material), the elastic element applying a spring-like force to hold the third conductor 110 (the force in response to the support of the housing 114 disconnects the compression of the elastic element between the portion of the hold-down member 112 in contact with the third conductor 110). For example, an elastic element such as a spring or a rubber projection may be used.

[0042] It should be understood that regardless of the material used to provide the disconnectable hold-down member 112, or the form or structure of any component of the disconnectable hold-down member, the hold-down member 112 can be electrically isolated from the third conductor 110 to provide a good conduction path between the first, second, and third conductors. The electrical isolation (i.e., insulation) can be provided by an insulating disconnectable hold-down member, or by the use of an insulating layer or section between the disconnectable hold-down member 112 and the third conductor 110. Optionally, the switch 100 includes an insulating layer disposed between the disconnectable hold-down member 112 and the third conductor 110. Optionally, the disconnectable hold-down member is insulating; for example, the support element 314 can be insulating. Optionally, in some sets of embodiments, the threaded element 320 in contact with the third conductor 110 can be insulating; for example, the threaded element can be formed of plastic.

[0043] Reference Figure 4 , the shear insert 310 of the disconnectable hold-down member 112 is described in more detail. The shear insert includes a threaded portion 316, a shearable portion 312 surrounding the threaded portion, and a plate 318. The shearable portion 312 is provided by a groove in the plate 318. The plate 318 is arranged to be rigidly supported by the housing so as to provide the necessary reaction force on the shear insert for the disconnectable hold-down member 112 to apply sufficient force to hold the third conductor 110 in physical and electrical contact with the first conductor 106 and the second conductor 108.

[0044] Reference Figure 5 , the assembly and manufacture of the switch 100 of the above-described set of embodiments are described.

[0045] The first conductor 106 and the second conductor 108 are inserted and molded into a portion 114a of the housing 114 (the conductors 106, 108 are placed in a mold and then plastic is poured into the mold to produce the housing portion 114a). The pyrotechnic actuator 102 is placed into the housing portion 114a, and the piston 120 is added. The piston 120 is arranged to fit against the sides of the housing portion 114a and the pyrotechnic actuator so as to provide a substantially sealed ignition chamber through the void in the piston 120.

[0046] Optionally, an arc quenching medium can be placed into the hollow around the piston. Then the third conductor 110 is added, and then the shear insert is added. These components are inserted from the bottom of the housing portion 114a. The third conductor is held in place against the first and second conductors by a threaded element 320 that engages a threaded portion of the shear insert. The applied force can be adjusted by adjusting the threaded element 320 at this manufacturing stage.

[0047] Alternatively, a portion 114b of the housing 114 can be applied before adjusting the threaded element. The housing portion 114b can optionally be welded to the housing portion 114a by ultrasonic welding or can be fixed to the housing portion 114a in any suitable manner. After joining, the plate of the shear insert 310 is then rigidly supported in a position between the two housing portions 114a, 114b. The threaded element 320 can be adjusted through a hole in the base of the housing portion 114b. For example, when the threaded element is a flat head screw, an Allen wrench or a hex wrench, a key can be used to adjust the threaded element 320. After adjustment, a cover can be provided to close the hole in the housing portion 114b to prevent leakage of any arc quenching medium during use.

[0048] Reference Figure 6 , describes a power system 640 including a switch 100. Specifically, the power system 640 can be the power system of a vehicle 600. With respect to a vehicle (e.g., a motor vehicle, a ship or a boat, or an aircraft, etc.), the power system encompasses the main components that generate electricity and transfer it to the road surface, water or air. This includes an engine, a transmission, a drive shaft and drive wheels (or other drive mechanisms, such as a propeller). In an electric or hybrid vehicle, the power system also includes, for example, a battery 660 and an electric motor. The switch 100 can be connected to an electrical circuit 650 within the vehicle 600 via connection contacts 106a, 108a of the first and second conductors, and the electrical circuit can optionally include a battery 660. Alternatively, the vehicle 600 for an electric vehicle can include the switch 100 in the absence of a power system 640, as Figure 6 illustrated in

[0049] An ignition signal can be provided from a remote controller or a remote power distribution unit 670 within a vehicle 600 to a connector pin 102a of a pyrotechnic actuator 102. This ignition signal can be issued in response to an external event. For example, when a switch 100 is connected to a battery 660 installed in the vehicle 600, the ignition signal can be sent to the pyrotechnic actuator 102 in response to a collision of the vehicle; the activation of the charge inside the igniter 102b can cause the third conductor 110 to separate from the first and second conductors so as to open the electrical circuit 650 and prevent current from flowing through the battery 660. This arrangement can improve safety in the case of a collision. Alternatively, the switch 100 and the remote controller 670 can be deployed in any other application where such a disconnection of the circuit is required.

[0050] Reference Figure 7 , describes a method 700 for using a switch 100 (e.g., the switch 100 of the first aspect) to open a current conduction path.

[0051] At step 710, the method includes optionally igniting a pyrotechnic actuator in response to a collision or other external event that triggers an ignition signal received by the pyrotechnic actuator. Any other trigger can be used to ignite the pyrotechnic actuator. At step 720, at the ignition of the pyrotechnic actuator, high-pressure gas is released into the ignition chamber. At step 730, this released gas exerts pressure (directly or indirectly) on a third movable conductor 110, which is arranged and held in a first position by a detachable holding member 112. Optionally, the third conductor is arranged in the ignition chamber. Optionally, the pressure is exerted by means of a piston that includes a void that at least partially defines the ignition chamber. In the first position, the third conductor 110 is arranged between the first conductor 106 and the second conductor 108 and is in (direct or indirect) electrical contact with the first conductor 106 and the second conductor 108 to define a current conduction path.

[0052] Optionally, in this example, the piston 120 accelerates downward due to the high-pressure gas, and as the piston moves downward, the third conductor 110 moves in the direction 130. The movement of the third conductor then pushes on a support element 314 of the holding member 112 and causes shearing of a shearable portion 312 of the detachable holding member, thereby disconnecting the detachable holding member 112.

[0053] At step 740, the separable holding member is disconnected (optionally sheared) by the actuating force, and the third conductor correspondingly moves, i.e., is displaced from the first position and towards the second position. In the second position, the third conductor 110 is electrically separated from the first conductor 106 and the second conductor 108; in other words, the switch 100 is opened. Thus, in response to the pressure applied at step 730 and the corresponding displacement or movement of the third conductor, the disconnection of the holding member at step 740 causes the opening of the current conduction path (step 750).

[0054] Optionally, at step 760, the arc formed when the third conductor is separated from the first and second conductors is suppressed or interrupted. This interruption can be achieved only by the relative movement of the third conductor (which elongates the arc) or by releasing an arc quenching medium (e.g., a medium including silica), which can be used to cool (and thus interrupt) the arc.

[0055] It should be noted herein that although the above describes various examples of the disconnect switch of the first aspect, these descriptions should not be viewed in a limiting sense. In fact, there are several variations and modifications that can be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A switch, comprising: an ignition chamber; a pyrotechnic actuator arranged to release gas into the ignition chamber upon ignition; a first conductor and a second conductor, the first conductor and the second conductor including connecting contacts; a third conductor movable in a direction from a first position towards a second position upon actuation of the pyrotechnic actuator; and a disconnectable holding member arranged to hold the third conductor in the first position prior to actuation of the pyrotechnic actuator, wherein the disconnectable holding member is arranged to disconnect depending on the actuation of the pyrotechnic actuator to allow movement of the third conductor, wherein in the first position, the third conductor is arranged between the first conductor and the second conductor and is in electrical and physical contact with the first conductor and the second conductor to define an electric current conduction path, wherein in the second position, the third conductor is electrically and physically separated from the first conductor and the second conductor, and wherein the contact surfaces where the first conductor contacts the third conductor and the second conductor contacts the third conductor generally extend perpendicular to the movement direction of the third conductor.

2. The switch according to claim 1, further comprising a housing arranged to enclose at least the third conductor and the disconnectable holding member, wherein the disconnectable holding member is supported by the housing.

3. The switch according to claim 1 or claim 2, wherein the disconnectable holding member is at least partially formed of plastic.

4. The switch according to claim 1 or claim 2, wherein the disconnectable holding member is arranged to shear upon actuation of the pyrotechnic actuator to allow the movement of the third conductor.

5. The switch according to claim 4, wherein the disconnectable holding member comprises: a support element configured to hold the third conductor against the first conductor and the second conductor prior to actuation of the pyrotechnic actuator; and a shearable portion arranged to shear around the support element upon actuation of the pyrotechnic actuator to allow the movement of the third conductor.

6. The switch according to claim 5, wherein the support element comprises: a threaded portion; and a threaded element configured to engage with the threaded portion, the threaded element being configured to hold the third conductor against the first conductor and the second conductor prior to actuation of the pyrotechnic actuator.

7. The switch according to claim 1 or claim 2, wherein the disconnectable holding member is arranged to apply a force in a direction opposite to the movement direction of the third conductor to hold the third conductor.

8. The switch according to claim 1 or claim 2, further comprising a piston arranged between the third conductor and the pyrotechnic actuator, the piston including a void at least partially defining the ignition chamber.

9. The switch according to claim 1 or claim 2, further comprising an arc quenching medium arranged to be disposed between the first conductor and the second conductor when the third conductor is in the second position.

10. The switch according to claim 1 or claim 2, wherein the disconnectable holding member and the pyrotechnic actuator are arranged on opposite sides of the third conductor.

11. A system, comprising: a switch according to any one of the preceding claims; and a controller arranged to supply a signal to the pyrotechnic actuator to ignite the pyrotechnic actuator.

12. A vehicle comprising a switch according to any one of claims 1 to 10 or a system according to claim 11.

13. The vehicle according to claim 12, wherein the vehicle is an electric vehicle.

14. A method for operating a switch, comprising: igniting a pyrotechnic actuator to release gas into an ignition chamber; applying pressure to a movable third conductor held in a first position by a disconnectable holding member depending on the released gas; wherein in the first position, the third conductor is arranged between a first conductor and a second conductor and is in electrical and physical contact with the first conductor and the second conductor to define a current conduction path; disconnecting the disconnectable holding member by the applied pressure and displacing the third conductor from the first position to a second position, wherein in the second position, the third conductor is electrically and physically separated from the first conductor and the second conductor; and opening the current conduction path by the displacement of the third conductor, the contact surfaces at which the first conductor contacts the third conductor and the second conductor contacts the third conductor generally extending perpendicular to the direction of movement of the third conductor.

15. The method according to claim 14, wherein disconnecting the disconnectable holding member comprises shearing the disconnectable holding member.

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