High voltage storage comprising an emergency cut

Abstract

The invention relates to a high-voltage accumulator for a high-voltage on-board electrical system of a motor vehicle, comprising: a switching circuit consisting of a plurality of accumulator units, each accumulator unit having at least one accumulator cell; a high-voltage switching device, by means of which a current path formed by the memory unit can be interrupted, and which has at least one bistable contactor that can be switched by means of a first supply voltage of the low-voltage supply device; an emergency low-voltage supply device for providing the first supply voltage for opening the at least one bistable contactor in the event of a failure of the low-voltage supply device, the emergency low-voltage supply device having: at least one of the memory units for providing the first supply voltage; and a low-voltage switching device that can be switched by a second supply voltage, which is smaller than the first supply voltage, for connecting the at least one memory cell to the at least one bistable contactor.

Description

Technical Field

[0001] The invention relates to a high-voltage storage device for a high-voltage onboard power system of a motor vehicle. The high-voltage storage device comprises a connection circuit consisting of a plurality of storage cells, wherein each storage cell has at least one storage cell. In addition, the high-voltage storage device comprises a high-voltage switching device, by which a current path formed by the storage cells can be interrupted and the high-voltage switching device has at least one bistable contactor that can be switched by a first supply voltage of a low-voltage supply device. In addition, the invention relates to an onboard power system and a motor vehicle. Background Art

[0002] Currently, interest is directed towards high-voltage storage devices or high-voltage batteries, which are used in particular as traction batteries for electrified motor vehicles, that is, electric vehicles or hybrid vehicles. Such high-voltage storage devices usually have a plurality of storage cells connected to one another, each of which can have a plurality of storage cells connected in series and / or in parallel. The high-voltage energy storage device has high-voltage connections, which can be connected, for example, to high-voltage components of a high-voltage onboard power supply of a motor vehicle, for example to an electric drive machine or a charging connection. Thus, the connected circuit consisting of the storage cells can be discharged and / or charged via the high-voltage connection.

[0003] In the event of a fault, such as in the event of a motor vehicle accident, the high-voltage onboard power supply must be converted into an intrinsically safe state and switched to a voltage-free state. For this purpose, the high-voltage connection is connected to a connection circuit consisting of a storage unit via a high-voltage switching device, which is usually powered by a low-voltage supply device of the low-voltage onboard power supply. The high-voltage switching device can, for example, have monostable contactors, which are kept in a closed state by the low-voltage supply device and automatically open when the low-voltage supply device fails. Such monostable contactors have a high energy demand, because the monostable contactors must be continuously powered by the low-voltage supply device in order to maintain the closed state.

[0004] As described in DE 10 2009 002 018 A1, bistable contactors can also be used, which only need to be powered by the low-voltage supply for the switching process, ie for opening or for closing. However, there is the problem that these contactors cannot open automatically when the low-voltage supply fails. Summary of the invention

[0005] The object of the present invention is to provide a solution for how a bistable contactor of a high-voltage accumulator of a high-voltage onboard power supply system of a motor vehicle can be opened safely and simply in order to provide an intrinsically safe state of the high-voltage onboard power supply system.

[0006] According to the invention, this object is achieved by a high-voltage storage device, an onboard power supply system and a motor vehicle having the features according to the respective independent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description and the drawings.

[0007] The high-voltage storage device for the high-voltage onboard power system of a motor vehicle according to the present invention comprises a connection circuit composed of a plurality of storage units, wherein each storage unit has at least one storage unit. The current path formed by the switching unit can be interrupted by a high-voltage switching device of the high-voltage storage device. The high-voltage switching device has at least one bistable contactor that can be switched by a first supply voltage of a low-voltage supply device. In addition, the high-voltage storage device has an emergency low-voltage supply device for providing the first supply voltage for opening the at least one bistable contactor when the low-voltage supply device fails. The emergency low-voltage supply device has: at least one storage unit in the storage unit for providing the first supply voltage; and a low-voltage switching device that can be switched by a second supply voltage that is smaller than the first supply voltage, for connecting the at least one storage unit to the at least one bistable contactor.

[0008] The invention further relates to an onboard power system for a motor vehicle, the onboard power system having a high-voltage onboard power system including a high-voltage storage device according to the invention and a low-voltage onboard power system including a low-voltage supply device, wherein the low-voltage supply device is electrically connected to the at least one bistable contactor of the high-voltage switching device of the high-voltage storage device. The motor vehicle according to the invention comprises the onboard power system according to the invention. The motor vehicle is in particular an electrified motor vehicle and has a high-voltage storage device as a drive battery or traction battery.

[0009] The high-voltage storage has a connection circuit composed of storage cells or battery cells. Each storage cell in the storage cells can have a storage cell or a connection circuit composed of multiple storage cells. Each storage cell can have, for example, a parallel circuit composed of multiple storage cells connected in series. The poles of the high-voltage storage, that is, the connection ends of the connection circuit, are connected to the high-voltage connection end of the high-voltage storage, and the high-voltage connection end can be electrically connected to the high-voltage components of the high-voltage vehicle power system, such as an electric drive machine, an air conditioning compressor, a charging connection end, etc. The high-voltage connection end can be used to extract and / or supply electrical energy to the high-voltage storage. In order to be able to switch the high-voltage vehicle power system to a voltage-free state in the event of a fault, the current path formed by the storage cell is interrupted. For this purpose, the high-voltage switching device can be connected to at least one of the high-voltage connection ends and the connection circuit and thus separate the at least one of the high-voltage connection ends from the connection circuit. For example, the high-voltage switching device has at least two bistable contactors, wherein, in particular, one bistable contactor is connected between one of the poles and one of the high-voltage connection ends. The high-voltage switching device can also be arranged between two storage cells and interrupt the circuit consisting of the storage cells in order to interrupt the current path.

[0010] Here, the at least one bistable contactor can be switched by applying a first supply voltage of a low-voltage supply device. The low-voltage supply device can, for example, have a low-voltage source of a low-voltage onboard power system, to which the at least one bistable contactor is electrically connected. The at least one bistable contactor can, for example, be connected to a battery controller of a high-voltage storage device, which is supplied with energy by a low-voltage source of the low-voltage onboard power system, so that the first supply voltage is supplied to the at least one bistable contactor via the battery controller.

[0011] In this case, the first supply voltage is only required for switching, that is, for changing the switching state, but not for maintaining the switching state. The at least one bistable contactor can be an electrically driven contactor or a contactor having at least two energizable coils, which can be changed from one switching state to a corresponding other switching state by applying a correspondingly polarized supply voltage, wherein each coil is used to establish the switching state. If the low-voltage supply device fails, for example in the form of a failure of the low-voltage onboard power supply system and / or the battery controller, and the first supply voltage is thus lost, switching of the bistable contactor is no longer possible.

[0012] In order to be able to switch the high-voltage on-board power grid to no voltage even when the conventional low-voltage supply device fails, the high-voltage storage device has an emergency low-voltage supply device. The emergency low-voltage supply device provides an alternative voltage at a first supply voltage level, and the at least one bistable contactor can be opened with the alternative voltage in an emergency. The alternative voltage is obtained from the connection circuit of the storage unit and therefore from the high-voltage accumulator itself. For this reason, in the case of failure of the conventional low-voltage supply device, at least one storage unit in the storage unit of the connection circuit is connected to the at least one bistable contactor, in particular two bistable contactors, of the high-voltage switching device by means of a low-voltage switching device, for example, through a voltage tap on the connection circuit. Therefore, the emergency low-voltage supply device is composed of at least one storage unit and a low-voltage switching device. Here, in particular, the number of mutually connected storage units for providing the alternative voltage is selected so that the alternative voltage corresponds to at least the first supply voltage.

[0013] The low-voltage switching device in particular has at least one pyrotechnic switching element and / or at least one relay and / or at least one electronic switch and / or at least one multistable switch. Preferably, the low-voltage switching device has two switching elements, wherein each switching element is connected to a voltage tap of the switched-on circuit and to two bistable contactors. In this case, the low-voltage switching device can receive a second supply voltage as an emergency cut-off trigger signal. In this case, the second supply voltage is lower than the first supply voltage. For example, the first supply voltage can be approximately 12V, while the second supply voltage can be up to 9V.

[0014] For example, the low-voltage switching device can be electrically connected to a low-voltage supply device that provides a first supply voltage and is designed to obtain a weakened voltage of the low-voltage supply device as a second supply voltage when the low-voltage supply device fails. The low-voltage switching device can therefore be switched by the failed low-voltage supply device in that the voltage of the low-voltage supply device weakened due to the failure is supplied to the low-voltage switching device, and the weakened voltage is no longer sufficient to switch the high-voltage switching device, but is still sufficient to close the low-voltage switching device. It can also be provided that the low-voltage supply device has a low-voltage energy accumulator, such as a capacitor, for actuating the low-voltage switching device.

[0015] Such a high-voltage store having at least one bistable contactor and an emergency shut-off device which is supplied by the high-voltage store itself is designed to be particularly energy-efficient and safe.

[0016] In a preferred construction, the high-voltage storage device has a cell monitoring electronic device, which is electrically connected to the voltage tap of the circuit for voltage measurement. The cell monitoring electronic device is connected to the at least one bistable contactor through a low-voltage switching device in order to provide the voltage tapped on the two voltage taps in the voltage tap as a first supply voltage. The cell monitoring electronic device, also known as CSC (cell monitoring circuit, CellSupervising Circuit), is designed to monitor the storage cell and also measure and analyze the voltage of the storage cell for this purpose. For this purpose, the cell monitoring electronic device is electrically connected to the storage cell through the voltage tap, wherein the energy supply of the cell monitoring electronic device is also provided by the storage cell in particular. The electrical connection between the storage cell and the cell monitoring electronic device is used to emergency cut off the at least one bistable contactor, in which the cell monitoring electronic device and at least one of the storage cells are electrically connected to the at least one bistable contactor through the low-voltage switching device. It can also be provided that the cell monitoring electronic device is designed to provide a second supply voltage for the low-voltage switching device of the emergency low-voltage supply device. The individual monitoring electronics can therefore also provide an emergency shut-off triggering signal for the low-voltage switching device.

[0017] In particular, the cell monitoring electronics have an input connection, which is electrically connected to a voltage tap of the circuit, and an output connection, which is connected to the low-voltage switching device, wherein the input connection and the output connection are galvanically isolated. In this case, the cell monitoring electronics are designed to either bridge a partial voltage of the high-voltage storage device provided by the at least one storage unit and provide the partial voltage to the at least one bistable contactor as a first supply voltage, or to convert the partial voltage to a first supply voltage by means of a galvanically isolated DC voltage converter and provide the first supply voltage to the at least one bistable contactor. The alternative voltage provided by the at least one storage unit is thus provided at the input connections and is transmitted to the output connections galvanically isolated, converted or not converted.

[0018] The embodiments described with reference to the high-voltage store according to the invention and their advantages apply correspondingly to the onboard electrical system according to the invention and the motor vehicle according to the invention.

[0019] Further features of the invention are apparent from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned above in the description and the features and feature combinations mentioned below in the description of the drawings and / or shown only in the drawings can be used not only in the respectively indicated combination but also in other combinations or alone. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention will now be explained in more detail using preferred exemplary embodiments and with reference to the accompanying drawings.

[0021] Figure 1 An electrical high-voltage storage device for a high-voltage onboard power supply system of a motor vehicle is shown. DETAILED DESCRIPTION

[0022] The only Figure 1 An electrical high-voltage storage device 1 for a high-voltage onboard power supply system of a motor vehicle is shown. The high-voltage storage device 1 has a connection circuit 2, also referred to as a battery pack, which consists of storage cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, wherein each of the storage cells 3a to 3h has at least one storage cell 4. The connection circuit 2 has two poles P+, P-, wherein the positive pole P+ is connected to a first high-voltage terminal HV+ on the positive side and the negative pole P- is connected to a second high-voltage terminal HV- on the negative side. The high-voltage terminals HV+, HV- can be electrically connected to high-voltage consumers of the high-voltage onboard power supply system, for example.

[0023] In order to be able to switch the high-voltage onboard power grid to a voltage-free state, the high-voltage storage device 1 has a high-voltage switching device 5, which has two bistable contactors S+, S-. The first contactor S+ on the positive side is connected between the positive pole P+ and the first high-voltage connection terminal HV+. The second contactor S- on the negative side is connected between the negative pole P- and the second high-voltage connection terminal HV-. In order to change the switching state, the contactors S+, S- are supplied with the first supply voltage U1 of the low-voltage supply device 6, which here has a battery controller 7 of the high-voltage storage device. The battery controller 7 can be supplied with energy from the low-voltage onboard power grid of the motor vehicle. The high-voltage storage device 1 also has a cell monitoring electronic device 8, which is electrically connected to the voltage taps 9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i of the connection circuit 2 in order to monitor the cell voltage of each storage cell 4.

[0024] Since the bistable contactors S+, S- must be loaded with the first supply voltage U1 in order to implement the switching process, that is, to close and to open, the high-voltage storage device 1 has an emergency low-voltage supply device 10, which can provide the first supply voltage when the low-voltage supply device 6 fails 11. Here, the low-voltage supply device 10 includes storage units 3b, 3c, 3d, 3e, which are connected to the single-cell monitoring electronics 8 via voltage taps 9b, 9f and provide a voltage U. The voltage U corresponds to the first supply voltage and is bridged here by the single-cell monitoring electronics 8. The bridged partial voltage U can be provided to the bistable contactors S+, S- via a low-voltage switching device 12 of the emergency low-voltage supply device 10, which is connected to the single-cell monitoring electronics 8 and is connected to the bistable contactors S+, S- via a two-wire line 13. The low-voltage switching device 12 has a first switching element 14a and a second switching element 14b, which are connected in a potential-free manner to the voltage tap 9b and the bistable contactors S+, S- via the cell monitoring electronics 8, and which are likewise connected in a potential-free manner to the voltage tap 9f and the bistable contactors S+, S- via the cell monitoring electronics 8. The switching elements 14a, 14b can be, for example, pyrotechnic normally open contacts, which can be activated by the second supply voltage U2 to close the low-voltage switching device 12.

[0025] The second supply voltage U2 is lower than the first supply voltage U1 and can be provided, for example, by the cell monitoring electronics 8 or a failed low-voltage onboard power system. When the second supply voltage U2 is applied to the switching elements 14a, 14b, the switching elements are closed and the voltage U is provided to the bistable contactors S+, S-, which are then opened and cause the safe state of the high-voltage onboard power system.

Claims

1. A high-voltage storage device (1) for a high-voltage onboard power supply system of a motor vehicle, the high-voltage storage device comprising: - A connected circuit (2) consisting of a plurality of memory cells (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h), wherein: Each memory unit (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h) has at least one memory cell (4), a high-voltage switching device (5), by means of which a current path formed through the storage cells (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h) can be interrupted and which has at least one bistable contactor (S+, S-) which can be switched by a first supply voltage of the low-voltage supply device (6), It is characterized in that - An emergency low-voltage supply device (10), which is used to provide the first supply voltage for opening the at least one bistable contactor (S+, S-) when the low-voltage supply device (6) fails, and the emergency low-voltage supply device has: at least one storage unit (3b, 3c, 3d, 3e) of the storage units for providing the first supply voltage; and a low-voltage switching device (12) that can be switched by a second supply voltage that is smaller than the first supply voltage, so as to connect the at least one storage unit (3b, 3c, 3d, 3e) to the at least one bistable contactor (S+, S-).

2. The high-voltage storage device (1) according to claim 1, It is characterized in that The high-voltage switching device (5) has two bistable contactors (S+, S-), wherein each bistable contactor (S+, S-) is electrically connected to a high-voltage connection (HV+, HV-) of the high-voltage storage device (1) and is connected to the at least one storage unit (3b, 3c, 3d, 3e) providing a first supply voltage via a low-voltage switching device (12).

3. The high-voltage storage device (1) according to claim 1 or 2, It is characterized in that The low-voltage switching device (12) has at least one pyrotechnical switching element and / or at least one relay and / or electronic switch and / or multistable switch.

4. The high-voltage storage device (1) according to claim 1, It is characterized in that The high-voltage storage device (1) has a cell monitoring electronic device (8) which is electrically connected to voltage taps (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i) of a switching circuit (2) for voltage measurement, wherein the cell monitoring electronic device (8) is connected to the at least one bistable contactor (S+, S-) via a low-voltage switching device (12) for providing a first supply voltage tapped off at two of the voltage taps (9b, 9f).

5. The high-voltage storage device (1) according to claim 4, It is characterized in that The cell monitoring electronics (8) have an input connection electrically connected to a voltage tap (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i) of a switching circuit (2), and an output connection electrically connected to a low-voltage switching device (12), wherein the input connection and the output connection are in particular galvanically isolated.

6. The high-voltage storage device (1) according to claim 4 or 5, It is characterized in that The cell monitoring electronics (8) is designed to bridge a partial voltage of the circuit (2) provided by the at least one storage unit (3b, 3c, 3d, 3e), - and providing the partial voltage as a first supply voltage to the at least one bistable contactor (S+, S-) or - conversion into a first supply voltage by means of a galvanically isolating DC voltage converter and provision of the first supply voltage to the at least one bistable contactor (S+, S−).

7. The high-voltage storage device (1) according to claim 4, It is characterized in that The single-unit monitoring electronics (8) is designed to provide a second supply voltage for a low-voltage switching device (12) of an emergency low-voltage supply device (10).

8. The high-voltage storage device (1) according to claim 1, It is characterized in that The low-voltage switching device (12) can be electrically connected to a low-voltage supply device (6) providing a first supply voltage and is designed to obtain a weakened voltage of the low-voltage supply device (6) as a second supply voltage when the low-voltage supply device (6) fails.

9. The high-voltage storage device (1) according to claim 1, It is characterized in that The emergency low-pressure supply device (10) has a low-pressure energy store, in particular a capacitor, which is designed to provide a second supply voltage.

10. An onboard power supply system for a motor vehicle, comprising a high-voltage onboard power supply system including a high-voltage storage device (1) according to one of the preceding claims and a low-voltage onboard power supply system including a low-voltage supply device (6), wherein: The low-voltage supply device (6) is electrically connected to the at least one bistable contactor (S+, S-) of the high-voltage switching device (5) of the high-voltage storage device (1).

11. A motor vehicle comprising an onboard electrical system according to claim 10.

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