ELECTRICAL SYSTEM

Description

[0001] The invention relates to an electrical system according to the preamble of claim 1.

[0002] The pollutant emissions from combustion engines have been taken increasingly seriously in recent years. To reduce these emissions, the use of electric motors in the mobile sector is being strongly promoted. This is based on the assumption that the demand for electricity can be increasingly met by renewable energy sources.

[0003] To replace combustion engines with electric motors, large currents and high voltages are necessary in most cases. Therefore, a large number of electrical storage cells, currently mostly lithium-ion batteries, are connected in series.

[0004] An arrangement for simultaneously connecting a large number of power generating elements in series is described in DE 28 52 337 A1. In this arrangement, a switch with two fixed contacts and one movable contact is provided between all elements. The movement of the movable contacts into their closed position is achieved by increasing the pressure in a working fluid.

[0005] The individual cells typically operate at a voltage of approximately 3.6 V. Electric motors, especially those used in motor vehicles, require a voltage of more than 300 V, necessitating the connection of more than one hundred such cells. Some vehicles now even operate at voltages of around 700 V.

[0006] The live parts are well insulated, so that no voltage can be transmitted to users during normal operation. However, in mobile applications – unlike stationary installations – incidents can occur quickly, resulting in significant mechanical deformation. For example, in a collision, it cannot be ruled out that electrical insulation could be damaged and high voltages transmitted to parts that users might come into contact with. This could lead to serious injury or even death.

[0007] In stationary electrical systems, such high voltages occur, for example, in houses with photovoltaic systems installed on their roofs. If a fire breaks out, firefighters are exposed to a great danger, as the possibility of a voltage arc to people via the extinguishing water cannot be ruled out at these high voltages.

[0008] US Patent 9,013,070 B2 discloses a device for isolating, for example, a large number of series-connected photovoltaic modules to eliminate the danger posed by high voltages. For this purpose, switches are provided between the photovoltaic modules, which are open in their resting position. To close the switches, pneumatic pressure is built up, which closes each switch. A smoke detector or temperature sensor is also described; its activation releases the pneumatic pressure, causing the switches to move to their open position.

[0009] In stationary electrical systems, such high voltages occur, for example, in houses with photovoltaic systems installed on their roofs. If a fire breaks out, firefighters are exposed to a great danger, as the possibility of a voltage arc to people via the extinguishing water cannot be ruled out at these high voltages.

[0010] The invention is based on the objective of designing an electrical system according to the preamble of claim 1 in such a way that such dangers can be safely avoided after an unforeseen event.

[0011] The problem according to the invention is solved by an electrical system with the features of claim 1. By providing closed disconnect switches between storage / converter cells connected in series during normal operation of the electrical system, which are designed and / or arranged in such a way that they are opened when the event sensor is triggered, the high voltage in the event of an unforeseen event can be divided into smaller, harmless voltages.

[0012] For example, after an accident, a voltage may be present on parts of an electrically powered vehicle that the injured persons or any rescuers come into contact with; however, this voltage is so low that it cannot cause any damage. Naturally, the invention also significantly reduces the risk of fire after an accident, as the probability of short circuits in the wiring between the storage cells is considerably lowered by separating the circuit into isolated segments. When the invention is used in an electrically powered vehicle, the event sensor is advantageously designed as an impact sensor.

[0013] In the event of a house fire with a photovoltaic system mounted on its roof, the disconnect switches between the photovoltaic elements, which are so-called converter cells, are triggered, for example, by a smoke detector or another fire alarm. Here, too, the high voltage is then divided into smaller, harmless voltages, so that there is no danger to firefighters during firefighting operations.

[0014] The invention is applicable, among other things, to all electrically powered means of transport. Means of transport, as used here, include all devices for transporting persons and / or goods on land, water, and in the air. "Electrically powered" refers to all means of transport that are at least partially electrically powered. This also includes so-called hybrid vehicles, which are powered partly by an electric motor and partly by an internal combustion engine. The consumer circuit here includes, in particular, the drive system. In contrast, in a photovoltaic system, the consumer circuit includes an inverter and possibly an energy storage device.

[0015] All cells that store voltage and all cells that generate voltage are considered storage / converter cells. Storage cells can include, for example, rechargeable lithium-ion cells or pure charge storage devices such as capacitors. Converter cells include, among others, fuel cells and photovoltaic cells.

[0016] A sensor specifically designed for actuating the disconnect switches can be used as the event sensor. However, the signal from an existing event sensor is particularly useful. For example, the impact sensor of an existing airbag could be used in a vehicle, and an already installed smoke detector in a house with a photovoltaic system. The costs for the electrical system according to the invention can be reduced in this way.

[0017] Further details and advantages of the invention will become apparent from the dependent claims.

[0018] To achieve the aforementioned advantages, it is not strictly necessary to have a disconnect switch between every storage / converter cell. Depending on the output voltage of each individual storage / converter cell, for most known storage / converter cells it is sufficient for the disconnect switches to be located between groups of storage / converter cells that are grouped in such a way that each group outputs a voltage that is not harmful to humans. The output voltage of such a group of storage / converter cells should therefore ideally not exceed 50 V.

[0019] Advantageously, at least one additional disconnect switch is provided between the series-connected storage / converter cells and the consumer circuit, which is in a closed position during normal operation of the electrical system. In this way, the consumer circuit can be disconnected from the storage / converter cells in the event of an unforeseen incident. By using two additional disconnect switches, complete isolation between the consumer circuit and the storage / converter cells can even be achieved. For example, when using the electrical system according to the invention in a house with a photovoltaic system, the inverter of the consumer circuit can thus be completely disconnected from the photovoltaic system.

[0020] A particularly advantageous feature is the combination of at least one additional disconnect switch with a main switch, which, after the event sensor is triggered, is in a position where the consumer circuit is short-circuited to the ground of an electrically powered vehicle. The combined disconnect / main switch can thus function as an on / off switch during normal operation of an electrically powered vehicle and as a changeover switch in the event of an accident. In this way, the storage / converter cells can be disconnected from the consumer circuit when the vehicle is at rest.

[0021] A combined disconnect / main switch can also be provided between both the negative and positive terminals of the series-connected storage / converter cells and the consumer circuit, so that in the resting state the consumer circuit is completely disconnected from the storage / converter cells. After an accident, the consumer circuit is then grounded on both sides. This potential-free state may also be desirable in a vehicle during periods of inactivity. In this case, the combined disconnect / main switches are designed to function primarily as changeover switches. Ideally, the potential drop to ground after switching occurs via a resistor.

[0022] Preferably, the disconnect switches have a contact pin that is movable within a sleeve containing at least two contact rings, one contact ring being connected to the negative terminal of one storage / converter cell and the other contact ring being connected to the positive terminal of another storage / converter cell. In the normal, closed position of the disconnect switch, an electrical connection exists between the two contact rings via the contact pin. This means that the two storage cells are connected in series by the disconnect switch. Upon activation of the event sensor, this connection is broken, thus disengaging the series connection.

[0023] The disconnect switches can be actuated in various ways. For example, each disconnect switch can be equipped with a solenoid powered by a standard 12V battery. In this case, an energy storage device is provided that pushes the disconnect switch into its open position. Consequently, the disconnect switch is only closed when battery voltage is applied to the solenoid. The event sensor then simply interrupts the connection to the 12V battery. Afterward, all disconnect switches move to the open position. This design has the additional advantage in a vehicle that the voltage is also distributed each time the vehicle is switched to its standby position.

[0024] However, in the event of an unforeseen incident, such as a collision or fire, situations may arise where severe mechanical deformation, exposure to intense heat, or high acceleration prevents the energy storage device from being triggered. Therefore, a gas generator, which can be triggered by the event sensor, is particularly advantageous. The gas pressure generated by the gas generator allows the disconnect switches to be moved from the closed to the open position. The gas pressure produced by such generators is typically high enough to function effectively even under adverse conditions, reliably moving the contact bolts to the open position of the disconnect switches. Furthermore, the gas has a very beneficial effect if an arc should occur despite the rapid opening of the disconnect switches. In this case, the gas acts as a spark extinguisher.

[0025] According to the invention, the gas pressure of a gas generator is used to trigger several disconnect switches. For this purpose, a distribution system leading to several disconnect switches could be connected to a gas generator. However, it is particularly advantageous to connect the sleeves of several disconnect switches to form a switching tube, with the gas generator located at one end of the switching tube. In this way, several disconnect switches are connected in series in the direction of gas flow, and no distribution system is required, which would always involve some deflections and therefore a pressure drop.

[0026] When disconnect switches are connected in series, care must be taken to ensure that, upon activation of the gas generator, the contact pins do not move all the way to the contact rings of the next disconnect switch, thereby opening one connection while closing another. Therefore, the switching tube advantageously has notches between the disconnect switches. A notch, in this context, refers to any reduction in the inner diameter of the switching tube, regardless of whether it is created by a bead or ribs.

[0027] The force exerted on each contact bolt by the gas pressure should be approximately the same. Therefore, it is particularly advantageous for the contact bolts to have continuous gas passage openings concentrically or parallel to their central longitudinal axis, with the cross-section of the gas passage openings being smaller for contact bolts located further from the gas generator than for those located closer. This means that the surface area of ​​the contact bolts exposed to the gas pressure increases with increasing distance from the gas generator. With appropriate design of the gas passage openings, the force acting on each contact bolt thus remains approximately the same, since although the gas pressure decreases with increasing distance from the gas generator, the area exposed to the gas pressure increases.

[0028] In a particularly preferred embodiment of the invention in an electrically powered means of transport, a gas generator is provided which is connected to two switching tubes. Each switching tube has a plurality of contact pins and is equipped with a main switch at the end opposite the gas generator. Each main switch has one contact pin and three contact rings of the switching tube, wherein one of the contact rings is connected to the negative terminal or the positive terminal of a storage / converter cell connected in series, the second of the contact rings is connected to the negative terminal or the positive terminal of the consumer circuit, and the third of the contact ring is connected to the ground of the means of transport.In this embodiment, an optimum is achieved between the safety of users or helpers in the event of an accident involving an electrically powered means of transport and the costs incurred by this additional safety device.

[0029] Further details and advantages of the invention will become apparent from the description of an exemplary embodiment, which is explained in detail with reference to the drawing.

[0030] It shows: Fig. 1 a schematic representation of a circuit arrangement according to the invention in an electrically powered motor vehicle during driving, Fig. 2 the circuit arrangement made of Fig. 1 after an accident, Fig. 3 a schematic sectional view of a disconnect switch for connecting storage cells connected in series, Fig. 4 a disconnect switch as in Fig. 3after being triggered in an accident in its open position, Fig. 5 a schematic sectional view of a main switch for connecting a consumer circuit with a group of storage cells connected in series in the closed position and Fig. 6 the main switch made of Fig. 5 after being triggered in an accident.

[0031] The in the Figures 1 and 2The illustrated embodiment of a circuit arrangement for use in a means of transport according to the invention, for example in an electric vehicle, has a consumer circuit 22 which can be connected via two main switches 7 to a battery array consisting of several groups of storage cells 24. Each group of storage cells 24 consists of several individual storage cells connected in series, with the output voltage of each group remaining below 50 V. Assuming that lithium-ion cells with a voltage of 3.6 V each are used, a group 24 of 13 cells yields an output voltage of 46.8 V.

[0032] In the example shown here, seven such groups 24 are connected in series via disconnect switches 1. The construction of the disconnect switches 1 and the main switch 7 will be discussed in detail later. The voltage applied to the consumer circuit is approximately 330 V. If higher voltages are required, either storage cells with a higher output voltage can be used, or more groups 24 can be connected in series via additional disconnect switches 1.

[0033] A gas generator 23 is provided, which has two outputs, with a switching tube 3 connected to the gas generator 23 at each output. The disconnect switches 1 are connected by the switching tube 3 with contact rings 4 (see Fig. 3 ) and each a gas-operated contact bolt 2, the main switches 7 also through the switching tube 3 with contact rings 14, 15, 16 (see Figs. 5-6) and a differently designed contact bolt 13 is formed. In this way, three disconnect switches 1 and one main switch 7 are implemented on each side of the gas generator 23 such that all eight switches can be operated via the gas generator 23.

[0034] Furthermore, in the Figures 1 and 2 An impact sensor 26 and a control unit 25 are also shown. Typically, the control unit 25 and the impact sensor 26 do not necessarily have to be implemented as part of the circuit shown. For example, every vehicle used for passenger transport today has airbags, which are also equipped with gas generators. A control unit is used to trigger these airbags; it receives a signal from an impact sensor and converts this into an activation signal for the airbag gas generators. This signal can also be used to activate the gas generator 23 in the Figures 1 and 2to tap into. In this case, no specially installed impact sensor or control unit is required to activate gas generator 23.

[0035] In the Figures 3 and 4 A section of a disconnect switch 1 is shown in detail. The inner surface of the switching tube 3 has annular recesses for receiving the contact rings 4, 28. The contact rings 4, 28 are connected, in a manner not shown here, to the positive terminal of one storage cell and to the negative terminal of another storage cell, respectively. In the closed position of the disconnect switch 1 (see Fig. 3 ) the two contact rings 4, 28 are electrically connected to each other via the contact bolt 2.

[0036] Contact ring 4 is slightly thicker than contact ring 28. Simultaneously, contact bolt 2 has a correspondingly larger diameter in the area of ​​contact ring 28. Due to this design, when contact bolt 2 moves to the right in the opening direction, it only has to overcome friction with contact rings 4 and 28 for a very short distance. After this very short distance, contact bolt 2 can continue moving practically without frictional resistance.

[0037] In the opening direction, next to the contact bolt 2, the switching tube 3 is provided with a groove 5. This groove 5 serves to stop the contact bolt 2 when it is forced out of its position by the gas pressure of a gas generator. Fig. 3 The position shown is moved. In this way, a defined end position is achieved for the contact bolts 2.

[0038] In the open position of the disconnect switch 1, the contact bolt 2 engages it. Fig. 4The end position shown is reached. Here, the contact pin 2 no longer touches both contact rings 4, 28, but is possibly only in partial contact with the right contact ring 28. This eliminates the series connection of the two memory cells.

[0039] However, in Fig. 4 not the same disconnect switch as in Fig. 3 shown. In Fig. 4 To illustrate the different gas passage openings 6, a contact bolt is shown whose position is further away from the gas generator than the contact bolt from Fig. 3 .

[0040] It is clearly visible that the gas passage opening of the contact bolt in Fig. 3 larger than that of the contact bolt in Fig. 4 This means that the end face of the contact bolt, which opposes the gas pressure, is in Fig. 3 smaller than that of the contact bolt in Fig. 4Only a portion of the gas present at the end face passes through the gas passage opening in a contact bolt.

[0041] This leads to a pressure drop on the opposite side of the contact bolt. Therefore, the gas pressure at the next contact bolt in the series is lower. However, in order to maintain the thrust force generated by the gas pressure above a certain value at this contact bolt as well, the contact area on the end face of this contact bolt is larger, and consequently, the cross-section of the gas passage opening is smaller.

[0042] In the Figures 5 and 6Figure 1 shows an embodiment of a main switch 7 with a linear actuator 8 for its actuation. The linear actuator 8 is designed as a stepper motor, by which a push rod 11 can be linearly displaced along the axis of rotation of the stepper motor. The stepper motor has a stator 9 mounted stationary in the drive housing and a rotor 10 rotatably mounted within the stator 9. A threaded nut 17 is provided concentrically to the axis of rotation of the rotor 10; this nut is rotationally fixed to the rotor 10 but is slidably mounted along the axis of rotation of the rotor 10.

[0043] Also concentric to the axis of rotation of the rotor 10 is a push rod 11, which is mounted so that it is displaceable along the axis of rotation, but does not participate in the rotation of the rotor 10 or the threaded nut 17 which is fixedly connected to it. The push rod 11 has an external thread in the area of ​​the threaded nut 17, which is in operative contact with the internal thread of the threaded nut 17.

[0044] At its end opposite the main switch 7, the push rod 11 is provided with a push rod flange 20. This flange projects into a spring housing, which is fixedly mounted to the drive housing. Between the push rod flange 20 and the inner wall of the spring housing facing the drive housing is the spring 21, which slightly biases the push rod flange 20 against the inner wall of the spring housing opposite the drive housing.

[0045] The threaded nut 17 is connected to the round nut flange 18, which is located in a corresponding recess in the drive housing. Next to the recess for the nut flange 18, a solenoid 19 is attached to the drive housing. This solenoid 19 is equipped with a locking lever which, when the solenoid 19 is energized, locks the nut flange 18 and thus prevents the threaded nut 17 from moving in the direction of the rotor 10's axis of rotation.

[0046] The main switch 7 is designed such that the contact bolt 13 is slidably mounted within the fixed switching tube 3. The contact bolt 13 is designed as a hollow cylinder, which is closed at its end face facing away from the push rod 11. At its open end, it is connected to the push rod 11 via a predetermined breaking point 12.

[0047] The predetermined breaking point 12 is not explicitly shown in the drawing, but a possible embodiment will be explained below. The predetermined breaking point 12 is preferably designed as a separate component. It has an inner ring that is connected to the push rod 11. It also has an outer ring that is connected to the open edge of the hollow cylinder of the contact bolt 13. The inner and outer edges are connected to each other by three star-shaped rays.

[0048] The rays are designed to break when a predetermined force acts between the inner and outer rings. The rays therefore constitute the actual point of failure.

[0049] The switching tube 3 has three annular recesses in its inner wall into which the contact rings 14, 15, and 16 are inserted. The left contact ring 14 is in contact with the memory cells 24, the middle one 15 with the consumer circuit 22, and the right one 16 with ground. The contact pin 13 is designed to electrically connect any two contact rings together.

[0050] Between the left contact ring 14 and the middle contact ring 15, close to the middle contact ring 15, the gas outlet openings 27 are provided, through which the gas generated by the gas generator 23 can flow out as soon as the contact bolt 13 is in the Fig. 6 is located in the position shown.

[0051] The function of the invention will now be explained using an electric vehicle as an example. In the electric vehicle's rest position (not shown here), the two main switches 7 assume a position in which the contact pins 13 contact only the central contact ring 15. Therefore, no voltage is present at the consumer circuit 22.

[0052] The solenoid 19 of each main switch 7 is in the lowered position, so that the nut flange 18 is not blocked. In this position (not shown here), however, no force is exerted on the push rod 11 by the spring 21, since the push rod flange 20 rests against the right side wall of the spring housing.

[0053] The disconnect switches 1 are all located in the Fig. 1in the position shown. In this position, they simultaneously contact both contact rings 4, 28. This means that all groups of memory cells 24 are connected to each other, so the full voltage would be available. However, this voltage is not yet present at the load circuit 22.

[0054] When the ignition key is inserted into the ignition lock, solenoid 19 is energized via the 12V vehicle battery and moves into its locked position as described in the Figures 5 and 6 As shown. Now the linear motor 8 is also connected to the vehicle's electrical system.

[0055] When the ignition key is turned, the linear motor 8 is energized so that the rotor 10 rotates by a predetermined number of steps. During this process, the push rod 11 is moved into the Fig. 5The operating position shown is shifted. In this position, the contact pin 13 now connects the contact ring 14, which is connected to the memory cells 24, and the contact ring 15, which is connected to the consumer circuit 22. In this operating position, the consumer circuit 22 is supplied with voltage. The controls of the consumer circuit 22 will not be explained further here.

[0056] When the electric vehicle is switched off, turning the ignition key back energizes the linear motor 8 so that the rotor 10 rotates in the opening direction. This pushes the push rod 11 and the contact bolt 13 back into their rest position (not shown here). The main switch 7 returns to its open position, in which the consumer circuit 22 is not connected to the storage cells 24 and therefore not supplied with voltage. When the ignition key is removed, the solenoid 19 returns to its unlocked position.

[0057] Should the 12 V on-board battery fail for any reason during operation of the electric vehicle, it would no longer be possible to disconnect the storage cells 24 from the consumer circuit 22, as the linear actuator 8 could no longer be energized. The spring 21 and the solenoid 19 are provided for this situation. Starting from the in Fig. 5 In the operating position shown, if the 12 V on-board voltage fails, the solenoid 19 drops out and the locking lever moves into its release position.

[0058] Starting from the in Fig. 5In the operating position shown, the force of the spring 21 now acts via the pushrod flange 20 on the pushrod 11 and moves it, together with the threaded nut 17 and the contact bolt 13, to the right until the pushrod flange 20 rests against the right inner wall of the spring housing. The main switch 7 is now in the open position (not shown), as described above. The connection between the storage cells 24 and the consumer circuit 22 is therefore interrupted.

[0059] Once a repair has been carried out, the electric vehicle can be put back into operation. When the ignition key is inserted into the ignition lock, the locking lever of the solenoid 19 cannot be moved into its locked position because it is prevented from doing so by the nut flange 18. The control unit (not shown here) therefore energizes the linear drive 8 in the opening direction. Since the push rod 11 cannot be moved further to the right, the threaded nut 17 is pushed back to the left into the rotor 10. After the threaded nut 17 reaches its normal position, as shown in the Figures 5 and 6 As shown, the locking lever of the solenoid 19 can now return to its locked position and the electric vehicle is ready to start again. The main switch 7 can be returned to its closed position by energizing the linear motor 8. Fig. 5 The operating position shown will be brought into place.

[0060] If the electric vehicle is involved in an accident, the consumer circuit 22 should be very quickly disconnected from the storage cells 24. At the same time, the groups of storage cells should also be separated from each other so that only voltages that are harmless to humans can occur.

[0061] Starting again from the one in Fig. 5 In the operating position of the two main switches 7 shown, the gas generator 23 in the middle between the two switching tubes 3 is ignited via an impact sensor 26 and a control unit 25 (see Fig. 1 The resulting gas pushes the contact bolts 2 of the disconnect switches 1 provided on both sides of the gas generator 23 into the Fig. 4The open position shown is shown. Since only one of the contact rings is now contacted by each contact bolt 2, there is no longer a connection between the individual groups of memory cells 24. In the case described here, only voltages of approximately 46.8 V can therefore be transmitted to electrically conductive parts of the electric vehicle. Thus, there is no longer any danger to people.

[0062] Since the contact pins 2 of the disconnect switches 1 all have gas passage openings 6, sufficient pressure is generated in front of the contact pins 13 of the two main switches 7 to be effective. This causes the predetermined breaking point 12 to break, and the contact pin 13 is pushed to the right until it rests against the side wall of the switch housing facing the linear actuator 8. This position of the main switch 7 is in Fig. 6shown. To prevent the internal pressure from causing an explosion of the switching tube 3, gas vent openings 27 are provided between the left contact ring 14 and the middle contact ring 15, which only become fully open when the contact bolt is completely in the position shown.

[0063] The contact bolt 13 represents in Fig. 6 A connection is established between contact ring 15, which is connected to the consumer circuit 22, and contact ring 16, which is connected to ground. In this way, in the event of an accident, not only can the consumer circuit be disconnected from the storage cells, but they can also be discharged. In the Figures 1 and 2In the illustrated embodiment, two main switches 7 are provided, wherein the contact ring 15 of one main switch is connected to the positive terminal of the consumer circuit 22 and the contact ring 15 of the other main switch is connected to the negative terminal of the consumer circuit 22. In this case, in the event of an accident, both the negative and the positive terminals of the consumer circuit are grounded. Reference symbol list:

[0064] 1 Disconnect switch 2 Gas pressure driven contact bolt 3 Switching tube 4 First contact ring 5 Stop bead 6 Gas passage opening 7 Main switch 8 Linear actuator 9 Rotor 10 Stator 11 Push rod 12 Shear point 13 Contact bolt of the main switch 14 Contact ring with connection to the storage cells 15 Contact ring with connection to the consumer circuit 16 Contact ring with connection to ground 17 Hex nut 18 Round nut flange 19 Solenoid with locking lever 20 Push rod flange 21 Spring 22 Consumer circuits 23 Gas generator 24 Storage cells or groups of storage cells 25 Control unit 26 Impact sensor 27 Gas outlet opening 28 Second contact ring

Claims

1. An electrical system having a load circuit (22) and a plurality of storage / converter cells (24), which are connected in series, for supplying the load circuit (22), and also having an event sensor (26), characterized in that disconnect switches (1), which are closed in normal operation of the electrical system, are provided between storage / converter cells (24) that are connected in series, which disconnect switches are realized and / or arranged such that they are opened in the event of triggering of the event sensor (26), wherein a gas generator (23) is provided which can be triggered by means of the event sensor (26), wherein the disconnect switch (1) can be brought from the closed into the open position by means of the gas pressure generated by the gas generator (23).

2. The electrical system according to Claim 1, characterized in that the disconnect switches (1) are located between groups of storage / converter cells (24), which are combined such that each group outputs a voltage that is not hazardous for humans.

3. The electrical system according to either of Claims 1 and 2, characterized in that at least one additional disconnect switch (7) is provided between the storage / converter cells (24), which are connected in series, and the load circuit (22), which additional disconnect switch is in a closed position in normal operation of the electrical system.

4. The electrical system according to Claim 3, characterized in that the at least one additional disconnect switch is combined with a main switch (7) which, following triggering of the event sensor (26), is in a position in which the load circuit (22) is short-circuited with the chassis ground (16) of an electrically driven means of locomotion.

5. The electrical system according to any one of Claims 1 to 4, characterized in that the disconnect switches (1) have a contact stud (2) which can be moved in a bush (3) having at least two contact rings (4, 28), wherein one contact ring is connected to the negative pole of a storage / converter cell (24) and the other contact ring is connected to the positive pole of a different storage / converter cell (24).

6. The electrical system according to Claim 5, characterized in that the bushes of a plurality of disconnect switches (1) are connected to form a contact tube (3), wherein the gas generator (23) is provided at one end of the contact tube (3).

7. The electrical system according to Claim 6, characterized in that the contact tube (3) has notches between the disconnect switches (1).

8. The electrical system according to either of Claims 6 and 7, characterized in that the contact studs (2) have continuous gas outlet openings (6) concentrically or parallel to their central longitudinal axis, wherein the cross section of the gas outlet openings (6) is smaller in the case of a contact stud with a larger distance from the gas generator (23) than in the case of a contact stud with a smaller distance from the gas generator (23).

9. The electrical system according to any one of Claims 6 to 8 in an electrically driven means of locomotion, characterized by the following features: • two contact tubes (3) are connected to a gas generator (23) • a multiplicity of contact studs (2) is provided in each contact tube (3) • the contact tubes (3) are provided with one main switch (7) in each case at the end opposite the gas generator (23) • each main switch (7) has a contact stud (13) and three contact rings (14; 15; 16) of the contact tube (3), wherein one of the contact rings (14) is connected to the positive pole of a storage / converter cell, which is connected in series, the second of the contact rings (15) is connected to the negative pole or the positive pole of the load circuit and the third of the contact rings (16) in each case is connected to the chassis ground of the means of locomotion.