AT524425B1 - Device for safely disconnecting a high-voltage battery - Google Patents

Abstract

The invention relates to a device for safely disconnecting a high-voltage battery (11) in a vehicle, having a pyrotechnic disconnecting device (12), an at least partially capacitive and/or inductive intermediate circuit and a motor/generator, the pyrotechnic disconnecting device (12) between the high-voltage battery (11) and the intermediate circuit and is set up for quickly disconnecting the high-voltage battery (11) from the intermediate circuit, and a discharge resistor (16) is also provided, the discharge resistor (16) being set up for discharging the intermediate circuit, characterized in that it is the discharge resistor (16) is an NTC resistor.

Description

description

DEVICE FOR SAFE DISCONNECTING OF A HIGH VOLTAGE STORAGE STORAGE

The invention relates to a device for safely disconnecting a high-voltage battery in a vehicle, with a pyrotechnic disconnecting device, an at least partially capacitive and/or inductive intermediate circuit and a motor/generator, the pyrotechnic disconnecting device being arranged between the high-voltage battery and the intermediate circuit and being fast disconnection of the high-voltage power storage device is set up from the intermediate circuit and a discharge resistor is also provided.

Safety devices for separating high-voltage power storage devices in vehicles are often known from the prior art, in order to prevent injury to those involved in the accident or to persons employed in the clean-up work, particularly in the event of an accident with deformation of the body of the vehicle. In the event of an accident or damage to the vehicle, an electric shock or the outbreak of a fire can result from an unwanted short circuit or uncontrolled contact between the vehicle parts and live parts of the vehicle drive. In order to avoid such injuries, suitable disconnecting devices are used in order - in the event of an accident - to disconnect the high-voltage power storage unit from the vehicle's live installations as quickly as possible. These separating devices often work with pyrotechnic material and are designed as so-called pyrotechnic separators, with an explosive charge and a corresponding working medium being used to build up pressure and thus a separating mechanism is set in motion, which leads to the separation of one or more electrical lines.

[0003] In the publication WO2018/091307A1, for example, a pyrotechnic switch is disclosed, a predetermined separation point of an electrical conductor being separated.

From the publication WO2018/091308A1 a safety method for a hybrid or electric vehicle is known, it being taught that in addition to a physical separation of an accumulator from an HV intermediate circuit, this HV intermediate circuit is discharged.

Further switches are known from the publications US2010328014A1, DE102020104617A1, US2020211801A1 and DE102019200861A1.

In this context, it is important to consider that high-voltage networks and corresponding high-voltage components are arranged in vehicles. This is used, for example, to operate converters, cooling units and/or heaters. In the event of an accident, damage to these high-voltage networks can also pose a risk. For example, in the event of an accident, insufficient shielding could damage a low-voltage component or even injure people.

[0007] Energy is also stored in such high-voltage networks, since components arranged in various ways represent, for example, capacitive and/or inductive loads.

The methods and devices known from the prior art prove in practice not to meet the new requirements and are inefficient.

It is therefore one of the objects of the present invention to develop a new type of device for safely disconnecting a high-voltage power storage device, in particular with a higher level of safety and/or higher efficiency.

The inventive object is achieved by a device according to claim 1.

According to a particular embodiment of the invention, a device is provided for safely disconnecting a high-voltage power storage unit in a vehicle, with a pyrotechnic disconnecting device, an at least partially capacitive and/or inductive intermediate circuit and a motor/generator, the pyrotechnic disconnecting device being located between the high-voltage power storage unit and the intermediate circuit is arranged and set up for rapid disconnection of the high-voltage power storage device from the intermediate circuit, and a discharge resistor is also provided

is seen, the discharge resistor being set up for discharging the intermediate circuit, characterized in that the discharge resistor is an NTC resistor.

Temperature-dependent resistors with a negative temperature coefficient are referred to as NTC resistors or NTC thermistors. NTC resistors conduct electricity better at higher temperatures than at low temperatures. In the event of a load when a voltage is applied, the cold NTC resistor conducts only little current due to its high resistance. As operation continues, the NTC resistor heats up, reducing its electrical resistance and increasing the current flow.

[0013] NTC resistors are usually made from metal oxides, for example iron oxide (Fe2O3), ZnTiQ4 and magnesium dichromate (MgCr2O4). NTC resistors are usually identified by their resistance at 25°C (R25).

A temperature-dependent resistor is particularly advantageous because the discharge contact can be closed very early. A discharge is thus already possible during the occurrence of an arc when the primary contact is opened by the pyrotechnic charge. While the arc that occurs at or in the area of the separation point of the primary contact is being extinguished, the discharge contact can already be contacted. This chronological sequence thus leads to energy inputs, in particular partial energy inputs from the battery and/or the intermediate circuit and/or other energies stored in the vehicle, for example inductances, in the discharge circuit at a particularly early point in time after the release function has been triggered, and at least partially dissipated via the discharge resistor to become.

The initial high resistance of the NTC at low temperatures protects the contact for contacting the discharge circuit or the discharge resistor during the switching process and/or reduces the current load on the resistor. In a special embodiment, when the primary contact is separated, intermediate circuit voltages of up to 1000V can be processed by the discharge resistor. Since the operating voltages of the energy stores are expected to increase further in the course of further technical developments, particularly in electric vehicles, the subject matter of the invention is of great technical and economic importance.

An additional advantage according to a preferred embodiment of the present device results from the lower peak power loading of the discharge circuit, lower necessary heat capacities and more time for heat dissipation, whereby a smaller installation space of the discharge circuit and/or smaller line cross-sections are made possible.

According to a particular embodiment of the present device, the discharge of the intermediate circuit via the discharge resistor according to the invention and the load on the other energy sources result in an increase in temperature of the discharge resistor and thus a reduction in resistance. According to a special embodiment, this leads to faster discharging of the intermediate circuit and thus to a reduction in the discharging times of the intermediate circuit.

According to a particular embodiment of the invention, the discharge resistor--at a nominal temperature of 25.degree. C.--has a nominal resistance of less than 1 kΩ.

According to a particular embodiment of the invention, the discharge resistor has a nominal resistance of <= 1 kΩ at ambient temperature.

According to a particular embodiment of the invention, the discharge resistor has a resistance <= 10Ω at 200°C.

According to a particular embodiment of the invention, the resistor withstands voltage loads of up to 1000V.

According to an advantageous embodiment, the discharge resistor for cooling at

at least partially embedded in a cooling gas or a cooling liquid. This can ensure improved heat dissipation and thus better cooling of the discharge resistor.

According to a particularly preferred embodiment, the NTC resistor is connected in series with a series resistor, in particular a fixed resistor, for example an ohmic resistor. According to further possible embodiments of the invention, various types of linear/ohmic or non-linear series resistors are possible as series resistors.

According to a particular embodiment, the invention is characterized by a device for safely disconnecting a high-voltage battery, the pyrotechnic disconnecting device being set up to disconnect a primary connection of a first conductor from a second conductor, the first conductor being provided for connection to the high-voltage battery and the second conductor is provided for connection to at least one consumer connected downstream of the pyrotechnic separating device, and a third conductor is provided, the pyrotechnic separating device being designed such that after the first conductor has been separated from the second conductor, the second conductor is used to produce a secondary connection can be connected to a third conductor, the third conductor being suitable for connection to the discharge resistor.

According to a particular embodiment of the invention, the third conductor is provided as a series resistor with a predetermined electrical resistance before the discharge resistor. According to a special one, the third conductor at least partially forms the series resistor.

According to a particular embodiment of the invention, a cooling device, for example a heat sink, is provided and the third conductor is at least partially embedded in a cooling gas and/or a cooling liquid in the cooling device. According to a particularly preferred embodiment, the third conductor and the discharge resistor are jointly embedded in a cooling gas and/or a cooling liquid. This is particularly advantageous when the third conductor is designed as a series resistor.

According to a particular embodiment of the device for safely disconnecting a high-voltage power storage device, the third conductor and/or the series resistor and/or the discharge resistor is at least partially embedded in a cooling gas and/or a cooling liquid.

According to a particular embodiment of the invention, the pyrotechnical separating device is designed to separate a connection of a first conductor from a second conductor, the first conductor being suitable for connection to the high-voltage power storage device and the second conductor being suitable for connection to at least one downstream of the pyrotechnical separating device Consumer is suitable and the pyrotechnic separation device is set up for separating the first conductor from the second conductor, which is offset in time, connecting the second conductor to a third conductor, the third conductor being suitable for connection to the discharge resistor. According to a particular embodiment of the invention, contact can be made with the discharge resistor while the arc of the separating device is still active.

According to a particular embodiment of the invention, this is characterized by a method for using a device according to the invention, wherein after the separation of the primary connection, the secondary connection in a time interval of at most 3 ms, preferably at most 1.5 ms, particularly preferably from at most 0.5 ms.

According to a particular embodiment, the invention is characterized by a method for safely disconnecting a high-voltage power storage device, in particular in a vehicle, with a pyrotechnic disconnecting device, a capacitive and/or inductive intermediate circuit and a motor/generator being provided, with the pyrotechnic disconnecting device is arranged between the high-voltage power storage device and the intermediate circuit and is set up for quickly disconnecting the high-voltage power storage device from the intermediate circuit, and a discharge resistor is also provided, the discharge resistor being used for discharging the intermediate circuit.

is directed, characterized in that the discharging resistor is an NTC resistor and the pyrotechnic disconnecting device is designed to disconnect a primary connection of a first conductor from a second conductor, the first conductor being provided for connection to the high-voltage power storage device and the second conductor is provided for connection to at least one consumer connected downstream of the pyrotechnic separating device, and a third conductor is provided, the pyrotechnic separating device being designed in such a way that after the first conductor has been separated from the second conductor, the second conductor is used to produce a secondary connection with a third conductor can be connected, wherein the third conductor is suitable for connection to the discharge resistor and the primary connection is mechanically disconnected and thereafter the secondary connection is mechanically closed while an arc is still present on the disconnected primary connection and burns.

According to a further preferred embodiment, the invention is characterized by a method for safely separating a high-voltage power storage device, after the mechanical separation of the primary connection, the secondary connection in a time interval of no more than 3 ms, preferably no more than 1.5 ms, particularly preferably at most 0.5 ms.

The invention is explained in more detail with reference to the following schematic, non-limiting figures. Show it:

[0033] FIG. 1 shows part of a schematic circuit diagram for a device for safely disconnecting a high-voltage power storage unit

[0034] FIG. 2 shows a schematic representation of a pyrotechnic separation device for use in a device for the safe separation of a high-voltage power storage device

[0035] FIG. 3 shows a schematic representation of a pyrotechnic separating device after triggering the separating function

[0036] FIG. 4 shows a schematic representation of a schematic circuit diagram for a device for the safe disconnection of a high-voltage power storage device

is shown schematically a part of a circuit diagram of a device for safe disconnection of a high-voltage power storage. The high-voltage power storage device 11 with all ohmic, capacitive and inductive load components, if applicable, is shown only schematically.

This high-voltage power storage device 11 is connected via a pyrotechnic separator 12 to a high-voltage network, which is shown in simplified form in the schematic representation by a capacitor 13 . This high-voltage network can be designed as part of an inverter circuit, for example. Also not shown is a motor/generator, which can also be part of the high-voltage network. A discharge resistor 16 can be switched via a suitable switching mechanism 14, which in turn can be controlled, for example, via a suitable trigger mechanism 15. According to a special embodiment of the present invention, the discharge resistor 16 is switched into a discharge circuit with the capacity 13 by the switching mechanism 14 during or after the separation of the high-voltage storage device 11 from the capacity 13 by the pyrotechnic separation device 12 . As a result, the energy stored in the capacitor 13 can be dissipated via the discharge resistor 16 . The discharge resistor 16 is designed as an NTC resistor.

shows a possible embodiment of a pyrotechnic separator 12 as a fuse 1 for separating two electrical conductors. A first conductor 2 is provided which is connected to a second conductor 5 in the configuration shown in FIG. The two conductors are connected via the piston 3 and the conductor section 4 of the second conductor and a connecting area 6 of the first conductor. A squib 9 is arranged inside the first conductor and can be actively controlled and ignited via 2 contacts 10 . The connection area 6, which is designed as a hollow cylinder with a thin cross section, is

leads is separated by the detonation of the squib. The plunger 3 is moved in the direction of the second conductor 5 as a result of this separation and the pressure created by the squib and the arc. The conductor section 4, which is also designed as a hollow cylinder with a thin cross section, is thereby deformed, in particular folded. This deformation and/or folding takes place in the folding space 7 of the fuse. The separation of the first conductor 2 from the second conductor 5 creates an arc in the separation area of the connection area 6 . An arc extinguishing medium 8, in particular silicone oil, is arranged in this area for the purpose of extinguishing the arc. According to a particular embodiment of the invention, the arc extinguishing medium 8 evaporates, as a result of which the internal pressure in this area increases and this pressure acts on the piston 3 and a sabot 18 . This causes the movement of the piston 3, the sabot 18 and thus the deformation and/or folding of the intermediate piece 4 in the direction of the second conductor 5. By increasing the distance between the two conductors 2 and 5 on the one hand and by the effect of the arc-extinguishing medium 8, in particular the silicone oil, on the other hand, any arcing that may occur is extinguished. The silicone oil evaporates endothermally and, on the one hand, contributes to the movement of the sabot by forming gas and, on the other hand, absorbs the energy of the arc and cools the fuse. As can be seen in FIG. 2, the fuse also has a third contact 17, which is contacted via the sabot 3 when the fuse is triggered. Thus, the fuse not only forms the pyrotechnic separator 12, but also forms the function of the switch 14 and its control 15 from. If the fuse 1 trips, the high-voltage power storage device is first disconnected, i.e. the first conductor 2 is disconnected from the second conductor 5. Due to the high currents and inductances that occur in electric vehicles, there is an arc that takes time to extinguish. If the contacting is already carried out during this erasing process, the result is a high load on the discharge resistor with a possible shortening of the total discharge time.

During the moving apart of the separate conductor materials, the intermediate piece 3 is guided to the third contact 17 and thus the discharge contact is made. The discharge circuit, as shown in FIG. 1, can thus be closed.

In Fig. 3, the fuse 1 is shown after triggering. According to a special embodiment, the time-staggered contacting takes place according to the following sequence: First, the squib 9 separates the connection area 6 of the first conductor. Due to the resulting pressure, the piston 3 is displaced in the direction of the discharge contact 17. The separation of the connection area 6 and thus the connection of the first conductor 2 to the second conductor 5 forms an arc. The displacement of the piston 3 towards the discharge contact 17 leads to the closing of the discharge contact 17. The high-impedance cold discharge resistor, which is contacted via the discharge contact 17, is therefore briefly subjected to a high voltage. Due to its high resistance, the discharge resistor and the discharge contact are protected from burning. As can be seen in FIG. 3, the conductor section 4 deforms and folds as a result of the movement of the piston 3. As the process progresses, the energy of the separating function is dissipated, for example due to the evaporation of the arc extinguishing medium 8, until the arc is extinguished. Additional gas and excess pressure are produced as a result of the evaporation of the arc-extinguishing medium 8, in particular the silicone oil. This overpressure acts on the piston 3 and the sabot 18 and leads to a promotion of the movement of the piston 3 in the direction of the discharge contact 17. In the course of arc quenching, the current path between the first conductor 2 and the second conductor 5 finally becomes highly resistive and the further discharge of the intermediate circuit via the discharge resistor, which heats up and thus becomes low-resistance.

In Fig. 4, a series resistor 19 is schematically provided compared to Fig.1. A fixed resistor can be used here, for example. Alternatively, of course, the third contact or discharge contact 17 can also be provided as a series resistor 19 . For this reason, the representation is only to be understood in a simplified and schematic manner. Furthermore, a cooling device 20 is provided schematically in FIG. 4 . This cooling device has a cooling gas and/or a cooling liquid, by means of which the third conductor or discharge contact 17 and/or the series resistor 19 and/or the discharge resistor 16 can be cooled. After a special

In this case, the third conductor or discharge contact 17 and/or the series resistor 19 and/or the discharge resistor 16 is embedded in the cooling gas and/or the cooling liquid. According to a particular embodiment, the cooling device 20 has a cooling housing in which, for example, the cooling gas and/or the cooling liquid is/are provided.

Claims (9)

patent claims 1. Device for safely disconnecting a high-voltage power storage device (11) in a vehicle, with a pyrotechnical disconnecting device (12), a capacitive and/or inductive intermediate circuit and a motor/generator, the pyrotechnical disconnecting device (12) between the high-voltage power storage device (11) and the intermediate circuit and is set up for quickly disconnecting the high-voltage power storage device (11) from the intermediate circuit, and a discharge resistor (16) is also provided, the discharge resistor (16) being set up for discharging the intermediate circuit, characterized in that the discharge resistor (16 ) is an NTC resistor. 2. A device for safely disconnecting a high-voltage power storage device according to claim 1, characterized in that the discharge resistor (16) - at a nominal temperature of 25°C - has a nominal resistance of less than 1 kΩ. 3. A device for safely disconnecting a high-voltage power storage unit according to claim 1 or 2, characterized in that the discharge resistor (16) is at least partially embedded in a cooling gas or a cooling liquid for cooling. 4. Device for safely disconnecting a high-voltage power storage device according to one of the preceding claims, characterized in that the NTC resistor is connected in series with a series resistor (19), in particular a fixed resistor. 5. Device for safely disconnecting a high-voltage power storage device according to one of the preceding claims, characterized in that the pyrotechnic disconnecting device (12) is set up for disconnecting a primary connection of a first conductor (2) from a second conductor (5), the first conductor ( 2) is provided for connection to the high-voltage power storage device (11) and the second conductor (5) is provided for connection to at least one consumer connected downstream of the pyrotechnic disconnecting device (12), and a third conductor is provided, the pyrotechnic disconnecting device (12) being so is designed that after separating the first (2) from the second conductor (5), the second conductor (5) can be connected to a third conductor to produce a secondary connection, the third conductor being used for connection to the discharge resistor (16 ) suitable is. 6. A device for safely disconnecting a high-voltage power storage device according to claim 5, characterized in that the third conductor at least partially forms the series resistor (19). 7. Device for safely disconnecting a high-voltage electricity storage device according to Claim 6, characterized in that a cooling device (20) is provided and the third conductor and/or the series resistor (19) and/or the discharge resistor (16) are each at least partially converted into a cooling gas and / or a cooling liquid is embedded in the cooling device (20). 8. A method for safely separating a high-voltage power storage device (11), in particular in a vehicle, with a pyrotechnical separating device (12), a capacitive and/or inductive intermediate circuit and a motor/generator, the pyrotechnical separating device (12) between the high-voltage power storage device (11) and the intermediate circuit and is set up for quickly disconnecting the high-voltage power storage device (11) from the intermediate circuit, and a discharge resistor (16) is also provided, the discharge resistor (16) being set up for discharging the intermediate circuit, characterized in that the discharge resistor is (16) is an NTC resistor and the pyrotechnic separating device (12) is set up to separate a primary connection of a first conductor (2) from a second conductor (5), the first conductor (2) for connection to the high-voltage power storage device ( 11) is provided and the second conductor (5) for connection to at least one of the pyrot echnical separation device (12) is provided downstream consumer, and a third conductor is provided, wherein the pyrotechnic separation device (12) is designed so that after separating the first (2) of the second conductor (5), the second conductor (5) can be connected to a third conductor to make a secondary connection, the third conductor being suitable for connection to the discharge resistor (16) and the primary connection being mechanically disconnected and thereafter the secondary connection is mechanically closed while an arc is still burning on the severed primary connection. 9. A method for safely separating a high-voltage power storage device according to claim 8, characterized in that after the mechanical separation of the primary connection, the secondary connection in a time interval of at most 3 ms, preferably at most 1.5 ms, particularly preferably at most 0.5 ms will be produced. 2 sheets of drawings