Fuse device for high-voltage applications

Abstract

The invention relates to a fuse device for high-voltage applications, comprising a housing (10); an actuation chamber (12) and an extinguishing chamber (14), which are formed in the housing (10); a busbar (16) which extends through the housing (10) and between the actuation chamber (12) and the extinguishing chamber (14); a separating element (34) which can be displaced out of the actuation chamber (12) and against the busbar (16) by means of an actuator (32) and by means of which a busbar section (43) can be displaced into the extinguishing chamber (14) in order to sever the busbar (16) at a predetermined breaking point (72); and a metal fabric (66). In order to prevent emissions in the event of small installations spaces by allowing the pressure produced upon triggering the actuator and the arc produced upon separating the busbar to be reliably absorbed, the invention proposes that the housing (10) has an inner wall (18) and an outer wall (20), wherein flow channels (80) are formed between an inner wall section (60), which surrounds the extinguishing chamber (14), and an outer wall section (62), which radially surrounds the inner wall section (60), said flow channels extending radially between the inner wall section (60) and the outer wall section (62) and through the housing (10) on both sides of the busbar (16) and at a distance to the busbar (16) so as to extend into at least one pressure-reducing volume (40), which is formed between an inner wall section (30) that delimits the actuation chamber (12) and an outer wall section (62) of the housing (10), said outer wall section surrounding the inner wall section (30) that delimits the actuation chamber (12).

Description

[0001] DESCRIPTION

[0002] Safety device for high-voltage applications

[0003] The invention relates to a fuse device for high-voltage applications with a housing, an actuation chamber and an arcing chamber formed in the housing, a busbar extending through the housing and between the actuation chamber and the arcing chamber, a separating body which can be displaced from the actuation chamber against the busbar by means of an actuator, through which separating body a busbar section can be displaced into the arcing chamber for severing the busbar at a predetermined breaking point, and a metal mesh.

[0004] Such safety devices are usually designed with a pyrotechnic igniter as an actuator and are used, particularly in vehicles with high-voltage applications such as hybrid vehicles or fully electric vehicles, to disconnect the power line between the battery and the consumers, in particular the vehicle's drive, in the event of an accident in a few thousandths of a second in order to avoid short circuits.

[0005] However, due to the high voltages, arcs occur between the free ends of the busbar when the busbars are separated, causing current to continue to flow for several seconds and resulting in extremely high short-circuit currents that can cause electric shocks to vehicle occupants or rescue personnel, which can be life-threatening. Since these arcs cannot be completely avoided, precautions must be taken to extinguish them as quickly as possible. US 10,622,176 B2 describes a pyrotechnic interrupter with two predetermined breaking points on its busbar. When the pyrotechnic igniter is ignited, a separating piston pierces the busbar, which is then moved into an extinguishing chamber. The extinguishing chamber is connected to exhaust ducts that lead on both sides to a first filter stage containing a metal mesh.Additional channels are formed in the housing, which in one version lead to a second filter element surrounding the first. From there, the gas stream is discharged. Additionally, the upper housing section contains the

[0006] Surrounding the actuation chamber and separated from the other filter elements by the busbar, further filter elements are arranged through which gas can penetrate via the recesses on the separating piston.

[0007] However, this design is problematic due to the design of the channels in the housing, the connection of the upper filter elements via the recess in the piston, and the emissions that occur during blow-out. To achieve this, it is necessary to use cores during production and to provide the busbar with through-holes. This leads to increased manufacturing costs and increased electrical resistance in the busbar.

[0008] The task therefore arises of creating a safety device for high-voltage applications that produces no emissions when triggered. Furthermore, such a safety device should be manufactured as cost-effectively as possible and require the smallest possible quantities of chemical substances for the exothermic reaction. Nevertheless, sufficient extinguishing and pressure relief should be achieved in the closed housing, which must be sufficiently strong. This task is solved by a safety device for high-voltage applications with the features of main claim 1.

[0009] The safety device according to the invention for high-voltage applications has a housing in which an actuation chamber and an extinguishing chamber are formed. An actuation chamber is a space in which an actuator is at least partially arranged. This can in particular be a pyrotechnic igniter, the triggering of which creates pressure which accelerates a separating body out of the actuation chamber. An extinguishing chamber is a space into which part of a busbar is displaced, thereby separating the busbar into at least two parts. The high voltages present create an arc, also known as plasma, between the separated busbar sections in the extinguishing chamber, which leads to burns. In order to keep these burns as short as possible, this arc must be extinguished as quickly as possible.The fuse device accordingly has a busbar that extends through the housing and between the actuation chamber and the arcing chamber. Furthermore, a separating body is arranged in the actuation chamber, which can be displaced against the busbar by means of the actuator. When the actuator is triggered, this separating body pushes a busbar section into the arcing chamber to sever the busbar at a predetermined breaking point. This separating body is thus itself at least partially displaced from the actuation chamber into the arcing chamber. A metal mesh is arranged in or near the arcing chamber. This metal mesh is melted by the arc and the pressure increase resulting from triggering, dissipating the existing thermal and kinetic energy.

[0010] According to the invention, the housing has an inner wall and an outer wall. This double-walled design significantly increases the pressure resistance of the safety device and thus prevents the housing from bursting. However, in order to also cool the resulting harmful gas and the gas flow resulting from volume expansion, thus extinguishing the arc more quickly, flow channels are formed between an inner wall section surrounding the arcing chamber and an outer wall section radially surrounding the inner wall section, through which the gas flow can be discharged.These flow channels extend radially on both sides of the busbar between the inner wall section and the outer wall section through the housing and spaced from the busbar into at least one pressure reduction volume which is formed between an inner wall section delimiting the actuation chamber and an outer wall section of the housing which surrounds the inner wall section delimiting the actuation chamber.This means that the gas, which is created on the one hand by the ignition of a pyrotechnic charge and on the other hand by an increase in gas volume due to the heat of the arc, is provided with a guided path and an additional pressure relief volume between the inner and outer walls. This, on the one hand, leads to a cooling of the gas and thus a reduction in volume and thus a pressure reduction. On the other hand, compared to known designs, an additional pressure relief volume is also provided into which the gas can flow. The double-walled design and the existing gas guide allow the pressure to be reduced to such an extent that the housing can withstand the existing pressure during triggering without having to vent gas to the outside. This prevents emissions.

[0011] Preferably, the inner wall section surrounding the arcing chamber has a side wall in which an opening is formed, which is located directly between the arcing chamber and the metal mesh. Through this opening, the arc can be directed specifically into the metal mesh, which is melted by the thermal energy and thus reduces the heat to extinguish the arc.

[0012] Furthermore, the metal mesh is preferably arranged fluidically between the opening and the flow channels, which extend on both sides of the busbar between the inner wall section surrounding the arcing chamber and the outer wall section surrounding the inner wall section, spaced apart from the busbar, into the at least one pressure relief volume. Thus, the gas is forced through the metal mesh as a path with the lowest flow resistance. This leads to rapid cooling and targeted gas flow to the pressure relief volume.

[0013] In an advantageous embodiment, the housing is constructed in three parts, with a first housing part forming the inner wall section delimiting the actuation chamber and the outer wall section surrounding the actuation chamber, a second housing part forming the outer wall section surrounding the arcing chamber and part of the inner wall section surrounding the arcing chamber, and a third housing part surrounding the busbar and forming part of the inner wall section surrounding the arcing chamber, and having a flange section arranged between the first housing part and the second housing part. A housing constructed in this way enables simple assembly of the safety device while simultaneously maintaining very high strength.

[0014] Furthermore, it is advantageous if the separator is guided by the third housing section during its movement within the arcing chamber. This guide prevents the separator from tipping and thus ensures precise positioning at the predetermined breaking point of the busbar. Furthermore, this guide prevents the arc from spreading along the outer circumference of the separator, allowing the arc to spread exclusively below the separator and to the opening behind which the metal mesh is located. This prevents the arc from jumping to the other side of the busbar.

[0015] Preferably, the opening behind which the metal mesh is arranged is also formed in the third housing part, so that the arc can pass directly from the chamber surrounding the separating piston through the opening to the metal mesh. This also facilitates the manufacture of the housing, since the opening is located on the wall of the third housing part, which is easily accessible during production and thus easy to demold.

[0016] To facilitate the necessary separation forces and thus enable the use of a smaller actuator, the busbar has a predetermined breaking point at which the separating body severs the busbar as it moves. The side wall of the inner wall section, in which the opening is formed, extends into the second housing part directly adjacent to the predetermined breaking point, and the opening is formed in a region of the side wall facing the busbar. By arranging this predetermined breaking point relative to the opening, the arc is guided to the opening and thus to the metal mesh immediately after the busbar is separated and thus in the immediate vicinity of its point of origin, significantly reducing the extinguishing time.

[0017] Preferably, supply channels are formed in a base of the second housing part, extending laterally from a base on which the metal mesh rests to the flow channels. The plasma flowing into the metal mesh must therefore flow through the entire metal mesh as it expands, then passes through the supply channels to the flow channels and from there into the pressure relief volume. This creates a forced flow throughout the entire available space due to the presence of cross-sections with lower flow resistance.

[0018] In a further embodiment of the invention, flow openings are formed in the flange section of the third housing part, through which the flow channels are connected to the pressure relief volume. These openings are located outside the busbar on the third housing part. This ensures easy accessibility to the pressure relief volume.

[0019] Furthermore, it is advantageous if the inner wall section defining the actuation chamber is connected to the outer wall section surrounding the inner wall section defining the actuation chamber via ribs. This significantly increases the pressure resistance of the housing in the area of ​​the pressure relief volume.

[0020] Preferably, the arcing chamber is axially delimited at least partially at the end remote from the busbar by an insert that bears radially against the metal mesh, wherein the insert is arranged axially between the arcing chamber and the supply channels. This insert allows the supply channels to be formed as simple grooves. The radial design prevents the plasma from seeking an alternative path and flowing back from the metal mesh into the arcing chamber. Instead, it ensures forced guidance to the supply channels.

[0021] To easily ensure this forced guidance, a gap is formed between the base of the second housing part and the insert, through which the metal mesh is fluidically connected to the supply channels. The plasma flows accordingly from the separate busbar across the opening in the metal mesh and from there between the base and the insert to the supply channels. Alternatively, the supply channels extend from an area of ​​the base on which the metal mesh rests. Thus, when using a flat insert, the gas flow can flow directly beneath the metal mesh into the supply channels of the base.

[0022] Preferably, the actuator is a pyrotechnic igniter located in the actuation chamber. These pyrotechnic igniters have very short actuation times and high release forces.

[0023] This creates a safety device for high-voltage applications in which the arc generated during separation is extinguished very quickly by the forced flow through the metal mesh, the supply channels, the flow channels, and the pressure relief volume. The safety device is nevertheless simple in design and assembly and features very high pressure resistance, thus completely preventing emissions. Instead, it ensures complete pressure relief and sufficient temperature reduction within the housing.

[0024] An embodiment of a safety device according to the invention for high-voltage applications is shown in the figures and is described below.

[0025] Figure 1 shows a side view of a pyrotechnic interrupter device according to the invention in a sectional view after actuation.

[0026] Figure 2 shows a perspective side view of the pyrotechnic interrupter device according to the invention from Figure 1, rotated by 90° relative to Figure 1, in a sectional view after actuation. Figure 3 shows a top view of the interior of the first housing part.

[0027] Figure 4 shows a head view into the interior of the second housing part in the base area.

[0028] Figure 5 shows a top view of the interior of the second housing part in a sectional view in the area arranged closer to the first housing part.

[0029] The safety device according to the invention, illustrated in the figures, is designed as a pyrotechnic interrupter device and consists of a housing 10, inside which an actuation chamber 12 and an extinguishing chamber 14 are formed, which are separated from one another by a busbar 16 extending through the housing 10 and via which, for example, a vehicle battery is connected to a consumer, such as a drive motor. The housing 10 is double-walled, with an inner wall 18 at least partially radially delimiting the extinguishing chamber 14 and the actuation chamber 12, and an outer wall 20 arranged radially spaced from the inner wall 18 and outwardly delimiting the safety device.

[0030] The housing 10 is constructed in three parts overall, wherein between a first housing part 22, in which the actuation chamber 12 is formed centrally, and a second housing part 24, in which the extinguishing chamber 14 is formed, a third housing part 26 is clamped with sealing rings 28 interposed by means of a screw connection (not shown).

[0031] The actuation chamber 12 in the first housing part 22 is radially surrounded by an inner wall section 30. An actuator 32, designed as a pyrotechnic igniter, is arranged inside this actuation chamber 12 in the area remote from the second housing part 24. Furthermore, in the non-triggered state, a separating body 34 in the form of a piston is displaceably arranged inside the actuation chamber 12. This separating body 34 is guided radially at least in sections through the inner wall section 30 and axially delimits the actuation chamber 12 in the direction of the actuator 32. Furthermore, the first housing part 22 has an outer wall section 36, which is connected to the inner wall section 30 of the first housing part 22 by ribs 38. A pressure relief volume 40 is formed between the inner wall section 30 and the outer wall section 36 by the free spaces between the ribs 38.

[0032] The third housing part 26 has a flange section 42, with which the third housing part 26 is clamped between the first housing part 22 and the second housing part 24. This flange section 42 surrounds the busbar 16 on all sides, with the exception of a busbar section 43, which, prior to triggering, axially directly adjoins the actuation chamber 12 and the arcing chamber 14. This busbar section 43 is delimited only on its radial sides by the third housing part 26, while the two sides of the busbar section 43 facing the actuation chamber 12 and the arcing chamber 14 are exposed to the actuation chamber 12 and the arcing chamber 14.Furthermore, two or more flow openings 44 are formed in the flange section 42, which are formed between an inner wall section 46 of the flange section 42 and an outer wall section 48 of the flange section 42 and are arranged in the axial extension of the pressure reduction volume 40 of the first housing part 22. A guide section 50 extends axially from the flange section 42, which guide section 50 engages in a receptacle 52 on the inner wall section 30 of the first housing part 22 in the region of the first housing part 12 facing the third housing part 26 and radially delimits the actuation chamber 12 in this region and thus guides the separating body 34.

[0033] In addition, the third housing part 26 has a guide section 54 which extends into the second housing part 24 and delimits the arcing chamber 14 on at least three sides, at least in sections.

[0034] This guide section 54, together with wall sections 58 projecting from a bottom 56 of the second housing part 24 in the direction of the first housing part, to which it is precisely aligned, forms an inner wall section 60 of the arcing chamber 14. This is arranged at a distance from an outer wall section 62 surrounding the inner wall section 60, which is formed by the second housing part 24.

[0035] An insert 64 is arranged on the base 56, which axially delimits the arcing chamber 14 towards the base 56 of the second housing part 24. Directly laterally adjacent to the insert 64, a metal mesh 66 is additionally arranged on the base 56, which extends axially between the inner wall section 60 and the outer wall section 62, which surround the arcing chamber 14. This extends axially to just before the flange section 42 of the third housing part 26. An opening 70 is formed in a side wall 68 of the inner wall section 60 or of the guide section 54 of the third housing part 26, via which opening a fluidic connection is established from the interior of the arcing chamber 14 to the metal mesh 66. This opening 70 is formed directly adjacent to the flange section 42, specifically on the side wall 68, which is arranged in the axial extension of a predetermined breaking point 72 of the busbar 16.As a result, when the actuator 32 is actuated by the movement of the separating body 34, the busbar section 43 is initially separated from the remaining busbar 16 at this position. A resulting arc is thus created in the immediate vicinity of the opening 70 during the separation, so that the arc can penetrate directly into the metal mesh 66 through the opening 70.

[0036] The thermal energy of the arc melts the metal mesh 66, thereby cooling the arc. However, increasing pressure is generated, which is further amplified by the ignition of the pyrotechnic igniter, creating a gas flow that must be dissipated to prevent the housing 10 from bursting.

[0037] In order to guide this gas flow into the pressure reduction volume 40 available between the inner wall section 30 and the outer wall section 36 of the actuation chamber 12, groove-shaped recesses are formed in the base 56 of the second housing part 24, which serve as supply channels 74. These extend from the area below the metal mesh 66 to the two sides of the second housing part 24 along the base 56, initially to below the insert part 64, so that an intermediate space 76 is formed between the base 46 and the insert part 64. From here, the supply channels 74 extend on both sides to the opposite side walls 78 of the outer wall section 62 of the second housing part 24.From here, the supply channels 74 merge into flow channels 80, which are formed by groove-shaped depressions on the inner wall surface of the outer wall section 36 and project upwards until they merge into the flow openings 44 of the third housing part 26, which in turn are fluidically connected to the pressure reduction volume 40.

[0038] If an emergency now occurs, for example due to a vehicle accident, the pyrotechnic actuator 32 is triggered. The separating body 34 is pressed against the busbar 16 by the explosion and separates the busbar section 43 at the predetermined breaking point 72 from the remaining busbar 16. As the separating body 34 continues to move, the busbar section 43 is initially rotated around the side of the free busbar section 43 opposite the predetermined breaking point. The high voltage creates an arc in the area of ​​the separation point between the free busbar ends. This arc can only expand through the opening 70 to the metal mesh 66, which is melted by the thermal energy. This cools and extinguishes the arc, but the resulting pressure must be dissipated by the explosion of the igniter and by the melting of the metal mesh and the resulting arc.This creates a flow through the metal mesh 66 along the path of least flow resistance, thus distributing the pressure via the supply channels 74 to the flow channels 80 and from there via the flow openings 44 to the pressure relief volume 40. The volume available here is large enough to reduce the pressure per unit area to such an extent that the housing 10 can withstand this pressure, particularly due to the high compressive strength provided by the ribs 38, and thus no gas escapes to the outside. Due to the subsequent cooling after the arc has been extinguished, the pressure inside the housing 10 subsequently decreases, thus also preventing any subsequent bursting.

[0039] This creates a safety device that reliably prevents emissions in a small installation space, while still maintaining high separation performance.

[0040] It should be clear that the scope of protection is not limited to the described embodiment, but various modifications are possible. In particular, different housing divisions or shapes of the components used can be provided. It may also be possible to omit the supply channels in the base, and route the flow channels from the back of the metal mesh upwards to the pressure relief volume. Furthermore, the insert, for example, can also be omitted.

Claims

P A T E N T A N S P R Ü C H E 1. A safety device for high-voltage applications comprising a housing (10), an actuation chamber (12) and an arcing chamber (14) formed in the housing (10), a busbar (16) extending through the housing (10) and between the actuation chamber (12) and the arcing chamber (14), a separating body (34) displaceable from the actuation chamber (12) against the busbar (16) by means of an actuator (32), through which separating body a busbar section (43) for severing the busbar (16) at a predetermined breaking point (72) can be displaced into the arcing chamber (14), a metal mesh (66), characterized in that the housing (10) has an inner wall (18) and an outer wall (20), wherein flow channels (80) are formed between an inner wall section (60) surrounding the arcing chamber (14) and an outer wall section (62) radially surrounding the inner wall section (60). are,which extend radially on both sides of the busbar (16) between the inner wall section (60) and the outer wall section (62) through the housing (10) and at a distance from the busbar (16) into at least one pressure reduction volume (40) which is formed between an inner wall section (30) delimiting the actuation chamber (12) and an outer wall section (62) of the housing (10) which surrounds the inner wall section (30) delimiting the actuation chamber (12).

2. Fuse device for high-voltage applications according to claim 1, characterized in that the inner wall section (60) surrounding the arcing chamber (14) has a side wall (68) in which an opening (70) is formed, which is arranged directly between the arcing chamber (14) and the metal mesh (66).

3. Fuse device for high-voltage applications according to claim 2, characterized in that the metal fabric (66) is arranged fluidically between the opening (70) and the flow channels (80) which extend on both sides of the busbar (16) between the inner wall section (60) surrounding the arcing chamber (14) and the outer wall section (62) surrounding the inner wall section (60) at a distance from the busbar (16) into the at least one pressure reduction volume (40).

4. Fuse device for high-voltage applications according to one of the preceding claims, characterized in that the housing (10) is constructed in three parts, wherein a first housing part (22) forms the inner wall section (30) delimiting the actuation chamber (12) and the outer wall section (32) surrounding the actuation chamber (12), a second housing part (24) forms the outer wall section (62) surrounding the arcing chamber (14) and part of the inner wall section (60) surrounding the arcing chamber (14), and a third housing part (26) surrounds the busbar (16) and forms part of the inner wall section (60) surrounding the arcing chamber (14), and has a flange section (42) which is arranged between the first housing part (22) and the second housing part (24).

5. Fuse device for high-voltage applications according to claim 4, characterized in that the separating body (34) is guided by the third housing part (26) during its movement within the arcing chamber (14).

6. Fuse device for high-voltage applications according to claim 4 or 5, characterized in that the opening (70) is formed in the third housing part (26).

7. Safety device for high-voltage applications according to one of claims 2 to 6, characterized in that the side wall (68) of the inner wall section (60), in which the opening (70) is formed, extends into the second housing part (24) immediately adjacent to the predetermined breaking point (72) of the busbar (16) and the opening (70) is formed in a region of the side wall (68) facing the busbar (16).

8. Safety device for high-voltage applications according to one of the preceding claims, characterized in that supply channels (74) are formed in a base (56) of the second housing part (24), which supply channels extend laterally from the base (56), on which the metal mesh (66) rests, to the flow channels (80).

9. Safety device for high-voltage applications according to one of claims 4 to 8, characterized in that flow openings (44) are formed in the flange section (42) of the third housing part (26), via which the Flow channels (80) are connected to the pressure reduction volume (40).

10. Fuse device for high-voltage applications according to one of the preceding claims, characterized in that the inner wall section (30) delimiting the actuation chamber (12) is connected to the outer wall section (32) surrounding the inner wall section (30) delimiting the actuation chamber (12) via ribs (38).

11. Fuse device for high-voltage applications according to one of claims 8 to 10, characterized in that the arcing chamber (14) is axially delimited at the end remote from the busbar (16) at least partially by an insert part (64) which bears radially against the metal mesh (66), wherein the insert part (64) is arranged axially between the arcing chamber (14) and the supply channels (74).

12. Fuse device for high-voltage applications according to claim 11, characterized in that an intermediate space (76) is formed between the bottom (56) of the second housing part (24) and the insert part (64), via which intermediate space the metal mesh (66) is fluidically connected to the supply channels (74).

13. Fuse device for high-voltage applications according to claim 11, characterized in that the supply channels (74) extend from a region of the base (56) on which the metal mesh (66) rests.

14. Safety device for high-voltage applications according to one of the preceding claims, characterized in that the actuator (32) is a pyrotechnic igniter which is arranged in the actuation chamber (12).

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