Pyrotechnic power line disconnection device with braking structure
The pyrotechnic power line disconnect device employs a multi-stage deformation section in the braking structure to address uncontrolled braking, achieving precise and controlled disconnection of the conductor rail section.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PIERBURG GMBH
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-04
AI Technical Summary
Existing pyrotechnic power line disconnect devices suffer from uncontrolled braking processes due to uncontrolled deformation of the braking structure, leading to imprecise stopping of the conductor rail section.
A pyrotechnic power line disconnect device with a multi-stage deformation section in the braking structure, designed as a stepped structure that sequentially collapses upon impact to provide controlled and precise braking.
The multi-stage deformation section allows for controlled and precise braking of the conductor rail section, ensuring accurate positioning and effective disconnection of the power line.
Smart Images
Figure EP2024083591_04062026_PF_FP_ABST
Abstract
Description
[0001] PI. P.24028. WO / EBFS November 26, 2024
[0002] - 1 -
[0003] Pyrotechnic power line disconnect device with braking structure
[0004] Description
[0005] The present invention relates to a pyrotechnic power line disconnecting device comprising a housing with a guide channel, a pyrotechnic propellant charge which can be ignited by means of a detonator, a separating piston which is axially displaceable in the guide channel and can be driven by means of the propellant charge, a conductor rail with a detachable conductor rail section against which the separating piston can be displaced by ignition of the propellant charge, an extinguishing chamber which is formed on a side of the conductor rail opposite the separating piston, and into which a conductor rail section which can be detached from the conductor rail can be displaced under the influence of the separating piston, wherein a braking structure is arranged in the extinguishing chamber, against which the conductor rail section impacts after being detached and which absorbs the kinetic energy of the conductor rail section by deformation.
[0006] Such a pyrotechnic power line disconnect device is used, particularly in vehicles with high-voltage applications such as hybrid or fully electric vehicles, to disconnect the power line between the traction battery and the consumers, especially the vehicle's drive system, within a few thousandths of a second in the event of an accident, thus preventing short circuits. To achieve this, the disconnecting piston, accelerated by the pyrotechnic propellant charge, pierces the conductor rail like a projectile with relatively high kinetic energy, breaking the section of the conductor rail out of the rail and propelling it forward. To prevent the piston from penetrating the housing wall, it is slowed by the deformable braking structure, which is located inside the housing on the side of the conductor rail facing away from the disconnecting piston and converts the kinetic energy into deformation energy.
[0007] Such a pyrotechnic power line disconnecting device is known, for example, from DE 11 2016 004 764 B4. The disclosed pyrotechnic power line disconnecting device has a braking structure formed by a ring body, PI. P.24028. WO / EBFS 26.11.2024
[0008] - 2 - which is located inside the housing on the side of the busbar facing away from the separating piston, and which is axially compressed when the separated busbar section and the separating piston collide, thereby braking the separating piston.
[0009] A disadvantage of the disclosed braking structure is that the braking process is relatively uncontrolled due to the uncontrolled deformation of the braking structure, which means, for example, that the power rail cannot be stopped with precise positioning.
[0010] Against this background, the present invention is based on the objective of creating a pyrotechnic current conductor disconnecting device with a braking structure that is improved compared to the prior art.
[0011] This problem is solved according to the invention by a pyrotechnic current conductor disconnecting device with the features of claim 1.
[0012] The pyrotechnic current-conductor disconnection device according to the invention comprises a housing with a guide channel. The guide channel extends axially through the housing and can have different cross-sectional shapes. A rectangular or circular cross-section of the guide channel is particularly preferred. The pyrotechnic current-conductor disconnection device further comprises a pyrotechnic propellant charge, which can be ignited by means of a detonator, for example, an electric detonator. The pyrotechnic propellant charge is arranged at least partially within a pressure chamber in the guide channel or preferably limits this chamber axially on one side. Furthermore, the pyrotechnic current-conductor disconnection device has a separating element, which is arranged to be axially displaceable in the guide channel and which can be driven by means of the propellant charge.The separating element is preferably designed as a separating piston, wherein the cross-sectional shape of the separating element essentially corresponds to the cross-sectional shape of the guide channel.
[0013] Furthermore, the pyrotechnic power line disconnect device has a busbar that extends transversely through the guide channel and divides it axially into the aforementioned pressure chamber and an extinguishing chamber. PI. P.24028. WO / EBFS 26.11.2024
[0014] - 3 -
[0015] The pressure chamber is thus arranged on a first axial side of the busbar, whereas the quenching chamber is arranged on a second axial side of the busbar. The separating element is positioned axially within the pressure chamber between the busbar and the pyrotechnic propellant charge, so that ignition of the propellant charge allows the separating element to be displaced against the busbar. Ignition of the propellant charge causes an explosion in which hot gases are released in the pressure chamber on the axial side of the separating element facing away from the busbar. These gases accelerate the separating element abruptly and propel it projectile-like against the busbar, whereupon the separating element pierces the busbar. The busbar has a removable section that can be detached by the action of the separating element and displaced into the quenching chamber.On both sides of the detachable busbar section, the busbar is fixed within the housing and extends outwards through the radial housing wall on both sides. Outside the housing, the two ends of the busbar are electrically connected to a power line of a circuit, so that when the busbar breaks down after the propellant charge is triggered, the power line is severed and the circuit is thus interrupted.
[0016] The propellant charge accelerates the separating element to an extremely high speed within a few thousandths of a second, which is only marginally reduced upon impact with the conductor rail. To prevent the severed conductor rail section, together with the separating element, from penetrating the housing at the extinguishing chamber end of the guide channel, a braking structure is arranged in the extinguishing chamber. The conductor rail section impacts this structure after being severed, and it absorbs the kinetic energy of the conductor rail section or the separating element through deformation. In this process, the kinetic energy of the conductor rail section or the separating element is converted into deformation energy.
[0017] According to the invention, the brake structure has a multi-stage deformation section. The deformation section is designed such that it deforms upon impact of the detached busbar section, thereby [PI. P.24028. WO / EBFS 26.11.2024].
[0018] - 4 -
[0019] The deformation section is designed to decelerate the conductor rail section or the separating element driving the conductor rail section. It is therefore configured as a stepped structure, preferably tapering towards the conductor rail. This multi-stage design achieves controlled deformation of the braking structure. Upon impact with the conductor rail section, the individual adjacent stages of the deformation section collapse sequentially and are pushed into one another, thus braking the conductor rail section in a controlled manner. The radial extent of the deformation section increases with each collapsed stage, thereby increasing the braking force with each subsequent collapse.The stepped design of the deformation section results in a relatively controlled deformation, which can be precisely adjusted by means of a specifically designed geometry of the individual steps and a defined number of steps. This enables controlled and relatively positionally accurate braking of the conductor rail section.
[0020] In a preferred embodiment of the invention, the deformation section has at least two stages, and particularly preferably at least three stages. The greater the number of stages, the smaller the axial extent of a single stage. This reduces the deformability of the axial sections of the individual stages, causing the deformation of the stages to occur mainly in the radial section, so that the stages are pushed into one another in a relatively controlled manner. At the end of the deformation process, the nested stages form a kind of solid block structure that completely and precisely stops the movement of the busbar section.
[0021] In a further particularly preferred embodiment of the invention, the braking structure in the deformation section is conical or pyramidal in shape. A conical shape is achieved by the deformation section having a circular outer shape with respect to its cross-section. A pyramidal shape, on the other hand, is achieved by the deformation section having a polygonal outer shape, for example a rectangular shape, with respect to its cross-section. In particular, in a conical shape, PI. P.24028. WO / EBFS 26.11.2024
[0022] - 5 -
[0023] In the design of the deformation section, each step has a circular cross-sectional shape, whereas in a pyramid-like design of the deformation section, each step has a polygonal cross-sectional shape.
[0024] Preferably, the braking structure is formed by a plurality of ring bodies of different sizes with respect to the radial direction, wherein the ring bodies are axially stacked on top of each other according to their radial size and firmly connected to one another. The ring bodies are either designed as circular rings or as polygonal rings. If the ring bodies are designed as circular rings, the outer diameter of each ring decreases in the direction of the conductor rail, thereby creating a multi-stage configuration of the braking structure and, in particular, of the deformation section. With a polygonal configuration of the ring bodies, the radial width of the ring bodies decreases accordingly in the axial direction. Here, the axial sections preferably extend exclusively in the axial direction.The radial sections, on the other hand, preferably extend exclusively in the radial direction, such that a right angle is formed between the axial sections and the radial sections, and the axial sections are arranged parallel to the radial inner wall of the guide channel. In the case of an annular body, the axial sections are thus, for example, cylindrical.
[0025] Preferably, the outer dimension of a ring body corresponds substantially to the inner dimension of an adjacent larger ring body. The outer dimension of the smaller ring body should therefore be equal to or slightly smaller than the inner dimension of the larger ring body. Furthermore, the shape of the outer surface of a ring body should also correspond to the shape of the inner surface of the adjacent larger ring body and be oriented accordingly. This ensures that the ring bodies can be slid into one another during the forming process and form a block structure.
[0026] Preferably, the brake structure is monolithic. The brake structure is thus designed as a single brake body, for example, as a plastic body, so that the individual stages are integrally connected. (See PI. P.24028. WO / EBFS 26.11.2024)
[0027] - 6 -
[0028] Transitions between two adjacent stages thus create predetermined breaking points where, during collapse, the individual stages detach from their respective neighbors and are subsequently pushed into one another. Depending on the geometry, there may be no detachment but rather a simple folding of the individual stages into one another. The monolithic design of the brake structure is relatively simple and cost-effective to manufacture, for example, using an injection molding process.
[0029] Preferably, the brake structure is arranged at the end of the guide channel on the extinguishing chamber side. The brake structure is preferably supported against an axial end wall that axially delimits the guide channel and is thus axially held by the housing.
[0030] In a further advantageous embodiment of the invention, the brake structure has a non-deformable base section. The base section preferably has, with respect to its cross-sectional shape, essentially at least partially the shape of the guide channel cross-section and can be held at least partially radially in the guide channel by a positive locking mechanism. The base section is designed to be so robust that it does not deform upon impact of the detached busbar section. The base section is arranged on the side of the brake structure facing away from the busbar, whereas the deformation section faces the busbar, so that the detached busbar section first impacts the deformation section, deforms it, and compresses it axially before impacting the base section and being stopped by it. The deformation section is axially supported by the base section in this process.
[0031] Preferably, the brake structure is closed at the end facing the conductor rail by a cover. The cover is preferably formed integrally with the brake structure and is thus molded onto it. The cover closes the interior of the brake structure on the conductor rail side.
[0032] Advantageously, the brake structure is positively locked in the housing. The brake structure rests axially on one side against a PI that axially limits the guide channel. P.24028. WO / EBFS 26.11.2024
[0033] - 7 -
[0034] The brake structure is attached to the end wall. Furthermore, it features a radially extending retaining section that rests against a stop on the housing side in the direction of the conductor rail, thus securing the brake structure axially in both directions. This allows the brake structure to be fixed in the guide channel without additional fasteners.
[0035] An embodiment of the present invention is described below with reference to the accompanying figures. These show:
[0036] Figure 1 shows a pyrotechnic current conductor disconnecting device according to the invention with an undeformed braking structure in a longitudinal section view before triggering,
[0037] Figure 2 shows the pyrotechnic current line disconnecting device according to the invention.
[0038] Figure 1 shows a deformed brake structure in a longitudinal section view after triggering,
[0039] Figure 3 shows the braking structure of the pyrotechnic power line disconnect device of Figure 1 in a longitudinal section view, and
[0040] Figure 4 shows the brake structure of Figure 2 in a top view.
[0041] Fig. 1 shows a pyrotechnic current conductor disconnection device 10 for disconnecting a current conductor between a traction battery and an electric drive motor in a circuit of an electrically powered vehicle, for example, a passenger car. The pyrotechnic current conductor disconnection device 10 comprises a housing 12, preferably made of plastic, which is formed in several parts and has a lower housing part 13 and an upper housing part 14. A guide channel 20 is formed in the housing 12, which extends axially through the housing 12 from the upper housing part 14 to the lower housing part 13 and has a substantially rectangular cross-section. A busbar 40 is arranged between the upper housing part 14 and the lower housing part 13, extending radially. PI. P.24028. WO / EBFS 26.11.2024
[0042] - 8 -
[0043] The conductor rail 40 extends outwards through the housing 12 on both sides at right angles to the axial direction. The conductor rail ends 46, 48 projecting from the housing 12 are electrically connected to the vehicle's electrical circuit, with the first conductor rail end 46 being, for example, electrically connected to the traction battery and the second conductor rail end 48, for example, electrically connected to the electric drive motor. The conductor rail 40 has a detachable conductor rail section 44 that extends transversely through the guide channel 20 and divides the guide channel 20 into a pressure chamber 24 in the upper housing part 14 and an extinguishing chamber 22 in the lower housing part 13. The pyrotechnic current conductor disconnection device 10 further comprises a pyrotechnic propellant charge 70, which is arranged at the axial end 25 of the guide channel 20 on the pressure chamber side.The pyrotechnic propellant charge 70 can be ignited by means of an electric detonator 72, which is arranged adjacent to the propellant charge 70 and is operatively connected to it. Furthermore, the pyrotechnic current conductor disconnecting device 10 comprises a separating element 30 designed as a separating piston 32, which preferably has a rectangular cross-section corresponding to the cross-sectional shape of the guide channel 20. The separating piston 32 is arranged axially in the pressure chamber 24 between the removable conductor rail section 44 and the pyrotechnic propellant charge 70, so that the separating piston 32 can be driven by the ignition of the propellant charge 70 and can be displaced relative to the conductor rail section 44. Upon ignition of the propellant charge 70, an explosion is triggered, releasing hot gases that lead to a pressure increase in the pressure chamber 24 and act on the separating piston 32.Due to the high pressure, the separating piston 32 is accelerated so strongly towards the conductor rail 40 that it pierces the conductor rail 40 in fractions of a second, tears the conductor rail section 44 out of the conductor rail 40, and drives it axially ahead of it into the extinguishing chamber 22. This interrupts the electrical connection previously established via the conductor rail 40 between the traction battery and the vehicle's electric drive motor.
[0044] The pyrotechnic power line disconnect device 10 further comprises a brake structure 50, which is designed as a monolithic brake body 51 made of plastic. The brake structure 50 is located in the extinguishing chamber 22 on the extinguishing chamber-side axial PI. P.24028. WO / EBFS 26.11.2024
[0045] - 9 -
[0046] The brake structure 50 is located at the end 23 of the guide channel 20 and projects axially into the guide channel 20 in the direction of the conductor rail 40. The brake structure 50 has a multi-stage deformation section 50A, which is conically shaped and tapers towards the conductor rail 40.
[0047] Figures 3 and 4 show the brake structure 50 in detail. The brake structure 50 further comprises a non-deformable base section 50B, which is arranged axially adjacent to the deformation section 50A at the end of the brake structure 50 facing away from the conductor rail 40 and which rests axially against an axial guide channel end wall 26 at the extinguishing chamber-side end 23 of the guide channel 20, as shown in Figure 1.
[0048] Compared to the deformation section 50A, the base section 50B has a significantly thicker wall, resulting in a considerably higher structural stability for the base section 53 than for the deformation section 50A. The base section 50B is positively locked in the guide channel 20. For this purpose, the base section 50B has a shoulder 64 that abuts axially against a third housing part 16, as shown in Fig. 1 and Fig. 2. Furthermore, the shoulder 64 has a rectangular cross-sectional shape, as shown in Fig. 4, which also provides a positive locking connection for rotation within the housing 12.
[0049] The deformation section 50A has four stages 52, 54, 56, 58, which are formed by a plurality of ring bodies 53, 55, 57, 59 of different sizes with respect to the radial direction. Each ring body 53, 55, 57, 59 forms one stage 52, 54, 56, 58 of the deformation section 50A. The ring bodies 53, 55, 57, 59 are each formed as a circular ring and therefore each have a circular cross-section.
[0050] The ring bodies 53, 55, 57, 59 are arranged adjacent to one another and are monolithically joined. The outer diameter D of each ring body 53, 55, 57, 59 decreases in the direction of the busbar 40. Each ring body 53, 55, 57, 59 has an axial section 552, which is cylindrical, and a radial section 554, which is PI. P.24028. WO / EBFS 26.11.2024
[0051] - 10 -
[0052] The circular ring disc is formed. For the sake of clarity, the axial section 552 and the radial section 554 are shown here as examples only for one ring body. However, the other ring bodies also have corresponding axial and radial sections, which do not have their own reference numerals.
[0053] Each axial section 552 of an annular body 53, 55, 57, 59 is integrally connected to the respective radial section 554 of the adjacent larger annular body 53, 55, 57, 59. Furthermore, each axial section 552 of each annular body 53, 55, 57, 59 is integrally connected to the respective radial section 554 of the adjacent smaller annular body 53, 55, 57, 59. The smallest annular body 53 is closed on the busbar side by a cover 60. The largest annular body 59 is integrally connected to the base section 50B on the base section 50B side.
[0054] The inner diameter d of each ring body 53, 55, 57, 59 corresponds essentially to the outer diameter D of the adjacent smaller ring body 53, 55, 57, 59. Preferably, the inner diameter d of each ring body 53, 55, 57, 59 is equal to or slightly smaller than the outer diameter D of the adjacent smaller ring body 53, 55, 57, 59.
[0055] Upon impact of the detached busbar section 44, driven by the separating piston 32, the deformation section 50A deforms, causing the individual stages 52, 54, 56, 58 to collapse. This causes the respective connection of the individual ring bodies 53, 55, 57, 59 to break at the transition between the radial section 554 of one ring body 53, 55, 57, 59 and the axial section 552 of the adjacent ring body 53, 55, 57, 59, resulting in the smaller ring body 53, 55, 57, 59 being axially pushed into the adjacent larger ring body 53, 55, 57, 59. The force required for this deformation opposes the driving force of the separating piston 32, thereby braking the conductor rail section 44 and the separating piston 32 as the ring bodies 53, 55, 57, 59 slide into one another. In addition, friction arises between the walls of the nested ring bodies 53, 55, 57, 59, generating an additional braking force.Here, the braking force increases with each stage (52, 54, 56, 58) due to the increasing diameter. In this way, braking is relatively controlled and can be adjusted by varying the number of [PI.P.24028.WO / EBFS 26.11.2024].
[0056] - 11 -
[0057] The steps and their geometry can be predicted relatively accurately. Due to the lack of deformability of the base section 50B, the cut-out busbar section 44 is stopped precisely in position upon contact with the base section 50B, as shown in Fig. 2. The deformation of the braking structure 50, in particular of the deformation section 50A, is shown in Fig. 2 only as an example and does not necessarily correspond to the actual deformation.
Claims
PI. P.24028. WO / EBFS November 26, 2024 - 12 - Patent claims 1. Pyrotechnic power line disconnect device (10) comprising a housing (12) with a guide channel (20), a pyrotechnic propellant charge (70) which can be ignited by means of a detonator (72), a separating element (30) which is axially displaceable in the guide channel (20) and can be driven by means of the propellant charge (50), a conductor rail (40) with a detachable conductor rail section (44) against which the separating element (30) can be displaced by ignition of the propellant charge (50), an extinguishing chamber (22) which is formed on a side of the conductor rail (40) opposite the separating element (30), and into which a conductor rail section (44) detachable from the conductor rail (40) can be displaced under the influence of the separating element (30), wherein a braking structure (50) is arranged in the extinguishing chamber (22),the conductor rail section (44) impacts after being cut out and which absorbs the kinetic energy of the conductor rail section (44) by deformation, characterized in that the brake structure (50) has a multi-stage deformation section (50A).
2. Pyrotechnic power line disconnecting device (10) according to claim 1, wherein the deformation section (50A) has at least two stages (52, 54, 56, 58), particularly preferably at least three stages (52, 54, 56, 58).
3. Pyrotechnic power line disconnecting device (10) according to claim 1 or 2, wherein the braking structure (50) in the deformation section (50A) is cone-shaped or pyramid-shaped.
4. Pyrotechnic power line disconnect device (10) according to one of the preceding claims, wherein the braking structure (50) is provided by a plurality PI. P.24028. WO / EBFS November 26, 2024 - 13 - is formed of ring bodies (53, 55, 57, 59) of different sizes with respect to the radial direction, and wherein the ring bodies (53, 55, 57, 59) are stacked axially on top of each other according to their radial size and are firmly connected to each other.
5. Pyrotechnic power line disconnecting device (10) according to claim 4, wherein the outer dimension (D) of an annular body (53, 55, 57, 59) substantially corresponds to the inner dimension (d) of an adjacent larger annular body (53, 55, 57, 59).
6. Pyrotechnic power line disconnect device (10) according to one of the preceding claims, wherein the braking structure (50) is monolithic.
7. Pyrotechnic power line disconnecting device (10) according to one of the preceding claims, wherein the braking structure (50) is arranged at the extinguishing chamber side end (23) of the guide channel (20).
8. Pyrotechnic power line disconnecting device (10) according to one of the preceding claims, wherein the braking structure (50) tapers towards the conductor rail (40).
9. Pyrotechnic power line disconnect device (10) according to one of the preceding claims, wherein the brake structure (50) has a non-deformable base section (50B).
10. Pyrotechnic power line disconnecting device (10) according to one of the preceding claims, wherein the brake structure (50) is closed at the end (61) facing the conductor rail (40) by a cover (60). PI. P.24028. WO / EBFS November 26, 2024 - 14 - 11. Pyrotechnic power line disconnector (10) according to any one of the preceding claims, wherein the cover (60) is formed integrally with the braking structure (50).
12. Pyrotechnic power line disconnector (10) according to any one of the preceding claims, wherein the braking structure (50) is positively engaged in the housing (12).