Method for operating a high-voltage storage device of a motor vehicle and high-voltage storage device for a motor vehicle

Abstract

The invention relates to a method (100) for operating a high-voltage storage device (11) of a motor vehicle (10), comprising steps of operating the high-voltage storage device (11), comprising a cell pack (12) of battery cells (13) to provide a first predetermined output voltage (V1); of detecting a fault in at least one battery cell (13) P ) of the high-voltage storage (11); of determining a position (P) of the faulty battery cell (13 P ) in the cell packing (12); and of controlling the operation of the high-voltage storage device (11).

Description

[0001] The invention relates to a method for operating a high-voltage storage system of a motor vehicle, comprising steps of operating the high-voltage storage system, which has a cell pack of battery cells to provide a first predetermined output voltage; detecting a fault in at least one battery cell of the high-voltage storage system; determining the position of the faulty battery cell in the cell pack; and controlling the operation of the high-voltage storage system such that further battery cells arranged adjacent to the faulty battery cell are subjected to at least a reduced load. The invention also relates to a high-voltage storage system for a motor vehicle.

[0002] High-voltage storage devices, also known as traction batteries or accumulators, are used to provide electrical energy for powering electric motors in motor vehicles. These high-voltage storage devices typically consist of an arrangement of battery cells connected in parallel and series via a contacting device, all housed within a casing. The battery cells and the contacting device are typically encased or encapsulated in an adhesive structural foam to create a uniform structure and provide thermal and / or electrical insulation.

[0003] For example, if a battery cell is damaged and / or the current-carrying contact system detaches from a battery cell, unwanted and safety-critical short circuits and / or thermal events can occur, which in the worst case can spread to neighboring battery cells.

[0004] Against this background, an object of the invention is to improve a method for operating a high-voltage storage system of a motor vehicle or a high-voltage storage system for a motor vehicle. In particular, a high-voltage storage system is to be improved in such a way as to enable increased safety, especially in the event of damage and / or a fault in a battery cell of the high-voltage storage system.

[0005] This problem is solved by a method for operating a high-voltage storage device of a motor vehicle with the features of claim 1 and a high-voltage storage device for a motor vehicle with the features of claim 8. The dependent claims relate to advantageous further developments of the invention.

[0006] According to a first aspect, a method for operating a high-voltage storage device of a motor vehicle is specified, comprising steps of operating the high-voltage storage device, comprising a cell pack of battery cells to provide a first predetermined output voltage; detecting a fault in at least one battery cell of the cell pack or the high-voltage storage device; determining the position of the faulty battery cell in the cell pack or the high-voltage storage device; and controlling the operation of the high-voltage storage device such that further battery cells adjacent to the faulty battery cell are subjected to at least a reduced load, wherein a second predetermined output voltage is provided by means of the high-voltage storage device to supply at least one voltage converter of the cell pack or the high-voltage storage device.

[0007] This allows an area of ​​the cell pack containing the faulty and / or defective battery cell to be used to a reduced extent or not at all for energy supply or the provision of the second predetermined output voltage, thereby enabling the surrounding battery cells and the defective or faulty battery cell to operate in a gentler and safer manner. This can prevent the spread of a thermal event and / or short circuit and / or improve the safety of the high-voltage storage system. Furthermore, because the second predetermined output voltage, which is particularly lower than the first predetermined output voltage, can still be used to power at least one voltage converter, especially in a specific area or...The portion of the cell pack that is not directly connected to the defective battery cell may continue to be operated and / or used to supply other components, in particular at least one cooling device of the high-voltage storage unit and / or the motor vehicle.

[0008] According to a further aspect, a high-voltage storage device for a motor vehicle is specified, comprising a cell pack of battery cells for providing a first predetermined output voltage, a first voltage converter assigned to a first portion of the battery cells, and at least a second voltage converter assigned to at least another portion of the battery cells, and a monitoring circuit, wherein the monitoring circuit is configured to operate at least one portion of the battery cells at a reduced load and to operate or utilize another portion of the battery cells to supply the voltage converter assigned to it. This allows the motor vehicle, its components, and / or the high-voltage storage device to continue to be supplied with energy even if a portion of the high-voltage storage device is not operated or is operated at a reduced load.

[0009] A high-voltage storage system is, in particular, an energy storage device or traction battery for a motor vehicle, comprising several battery cells arranged in one or more cell packs. The housing of the high-voltage storage system defines an interior space in which the battery cells are housed or arranged. Cylindrical battery cells are primarily used, which can be provided in a cell pack. The battery cells, cell pack, or high-voltage storage system is configured to provide the first and / or second predetermined output voltage to operate components of a motor vehicle's high-voltage system, such as a drive motor, and / or to supply at least a portion of the first and / or second predetermined output voltage to at least one voltage converter.

[0010] The high-voltage storage system comprises at least two voltage converters, each configured to convert an output voltage provided by the battery cells of the high-voltage storage system, or at least a portion thereof, into a lower voltage, in particular a voltage in the range between 12 V and 60 V, for operating components of a low-voltage system of the motor vehicle. It is specifically provided that a first portion of the battery cells is assigned to a first voltage converter to supply it with electrical energy, and a second portion of the battery cells is assigned to a second voltage converter to supply it with electrical energy.

[0011] The monitoring circuit and / or battery management system (BMS) of the vehicle may be configured to monitor and / or control the battery cells of a portion or battery pack of the cell pack, or the cell pack itself, in order to generate or provide the first and / or second output voltage to supply at least one of the voltage converters and / or other components of the vehicle. In this context, a cell supervisory circuit (CSC) may, for example, monitor the voltage, temperature, and / or state of charge of each individual battery cell, particularly within a cell pack or portion of a predetermined number of battery cells, and may perform passive or active balancing of the battery cells to ensure that all battery cells are at the same voltage level, thereby improving the service life of the battery pack or cell pack.Furthermore, the monitoring circuit and / or the cell monitoring circuit can be configured to detect anomalies or a fault in a battery cell, such as over- and / or undervoltage, a short circuit and / or thermal problems, and can be configured to implement a protective measure such as at least partially switching off a battery pack or a portion of battery cells and / or at least reducing the load or operation of a battery cell or a portion of the battery cells.

[0012] The invention is based, among other things, on the idea of ​​excluding this and surrounding battery cells from the energy supply of the motor vehicle or its components in the event of a defective battery cell being detected, or at least using them in a reduced capacity for energy provision in order to conserve them, but still continuing to use at least a part of the battery cells of the cell pack or the high-voltage storage system in order to provide or ensure at least a minimal supply to other components, in particular for cooling the affected battery cell(s).

[0013] It is proposed that, after a fault has been detected and its location within the high-voltage storage system or cell pack has been determined, battery cells or portions of battery cells within the high-voltage storage system can be controlled in such a way that the use of adjacent battery cells or the portion of battery cells containing the faulty cell is reduced or eliminated for energy supply, particularly for the voltage converter(s) associated with it. Specifically, by dividing the cell pack into several sections, each with its own voltage converter, at least the voltage converter not supplied by the section containing the faulty cell can be fully operated with the available energy from its associated battery cells or portion of battery cells.This can improve the power supply to, for example, a cooling system, because the cooling system can be supplied with energy or voltage via the second output voltage to cool the critical part of the battery cells and / or to continue operating other essential vehicle components. This can improve the safety of the high-voltage storage system, particularly in the event of a battery cell failure.

[0014] In one embodiment, the at least one voltage converter is used to operate a cooling device. This cooling device can, for example, be at least one temperature management device for the high-voltage storage system, which is designed for the active and / or passive cooling of the battery cells or cell pack, in particular the affected portion of the battery cells, and / or be another heat exchange device, such as a heat exchanger and / or a heat pump, which can be used, in particular, for cooling or temperature control of a component in the vehicle. This allows the vehicle, its components, and / or the high-voltage storage system to continue to be cooled even if part of the high-voltage storage system is not, or can only be, used for energy supply at a reduced capacity.

[0015] In one embodiment, the second predetermined output voltage is used to operate at least one cooling device. This second predetermined output voltage can be provided, for example, by the high-voltage storage system, the second, unaffected portion of the battery cells, and / or the operable voltage converter. The second predetermined output voltage, particularly if it results from the reduced operation of a portion or the surrounding battery cells of the damaged or defective battery cell, or from a reduced output voltage compared to the first predetermined output voltage, can thus ensure a power supply for the cooling device. This prevents overheating of the high-voltage storage system and / or at least one other component by supplying power to the cooling device via the second predetermined output voltage, thereby enabling safe (minimal) operation of the vehicle.

[0016] In one embodiment, the second predetermined output voltage corresponds to approximately half of the first predetermined output voltage. The high-voltage storage system can comprise a first group of battery cells, which, for example, is assigned to the first voltage converter, and a second group of battery cells, preferably of the same number, assigned to a second voltage converter. When operating at reduced voltage, the half or group of battery cells containing the defective battery cell is deactivated. This allows at least half of the normally available output voltage to be used for the operation or (emergency) operation of the vehicle, for example, to enable safe parking of the vehicle.

[0017] In one embodiment, a first portion of the battery cells supplies a first voltage converter associated with these battery cells, and at least a second portion of the battery cells supplies at least a second voltage converter associated with this second portion, wherein the portion of the battery cells in which the defective battery cell is located is subjected to a reduced load. This allows a (minimum) output voltage to be maintained by the second, unaffected portion of the battery cells, while simultaneously ensuring that those battery cells in a portion affected by the defective battery cell are subjected to a reduced or no load in order to prevent the propagation of a thermal event and thus a safety-critical risk.

[0018] In one embodiment, the first and second battery cell groups comprise at least substantially the same number of battery cells. The second output voltage can, in particular, represent half of the possible, especially the first predetermined, output voltage when all battery cells are in operation. Half of this first predetermined output voltage can be sufficient to operate at least some components of the motor vehicle in emergency mode, thereby ensuring, for example, the safety of the high-voltage storage system by enabling cooling and / or the safety of the vehicle by enabling reduced operation, particularly up to a predetermined upper limit, of, for example, a drive motor.

[0019] In one embodiment, the reduced-load portion of the battery cells is used, under at least one predetermined condition, to supply the voltage converter associated with this portion or to provide the second predetermined output voltage. A predetermined condition can, for example, be the verification or determination of safe operation of the battery cells or the portion of the battery cells, particularly to a predetermined degree, and / or can include manual activation so that the second predetermined output voltage can be increased, for example, by additionally utilizing the reduced-load portion, in order to enable improved operation or an improved energy supply for the vehicle or its components and / or the high-voltage storage system, particularly with regard to operational reliability.

[0020] In one embodiment, the high-voltage storage system comprises means for detecting a fault in a battery cell, means for determining the position of the faulty battery cell, and a monitoring circuit configured to operate the portion of the system containing the faulty battery cell at a reduced load, depending on the determined position of the faulty battery cell. The means for detecting the fault or the position of the faulty battery cell can be provided by a cell monitoring circuit or the cell management system (CSC) to enable appropriate control of the high-voltage storage system or its individual battery cells by the monitoring circuit or the battery management system.

[0021] In one embodiment, the high-voltage storage system has at least one cooling device that can be supplied with power by the at least one voltage converter. The first and / or the second voltage converter can be used to supply the cooling device with electricity, particularly depending on the position of the battery cell and the permissible reduced load on the battery cells in relation to the defective battery cell. This allows, for example, cooling of the defective battery cell(s) or surrounding battery cells, which can be controlled based on their specific position. This can prevent the propagation of a thermal event in the high-voltage storage system and / or improve the safety of the high-voltage storage system.

[0022] According to a further aspect, a motor vehicle is proposed, comprising a high-voltage storage device as proposed herein, which is specifically configured to execute a method described herein and / or wherein the motor vehicle is configured to execute a method described herein. The effects and / or advantages described herein can be utilized by means of such a motor vehicle.

[0023] Further advantages and application possibilities of the invention will become apparent from the following description in conjunction with the figures. Fig. Figure 1 shows a schematic representation of a motor vehicle having a high-voltage storage device according to an embodiment of the present invention. Fig. Figure 2 shows a schematic flowchart of a method for operating a high-voltage storage device of a motor vehicle according to an embodiment of the present invention.

[0024] Fig. Figure 1 shows a motor vehicle 10 with a high-voltage storage device 11 for a motor vehicle 10 according to an embodiment of the present invention in a schematic representation.

[0025] The high-voltage storage device 11 comprises a cell pack 12 of battery cells 13 for providing a first predetermined output voltage V1, a first voltage converter 14a assigned to a first portion 13a of the battery cells 13, and a second voltage converter 14b assigned to at least one further portion 13b of the battery cells 13. The first portion 13a and the second portion 13b of the battery cells 13 or of the cell pack 12 can comprise at least substantially the same number of battery cells 13.

[0026] Furthermore, the high-voltage storage device 11 has a control unit 15 with a monitoring circuit 16, means 17 for determining a fault in a battery cell 13 and means 18 for determining a position P of the faulty battery cell 13 P The monitoring circuit 16 is configured to operate at least one of the components 13a, 13b of battery cells 13 with a reduced load or voltage and to operate another component 13a, 13b of battery cells 13 to supply the associated voltage converter 14a, 14b. In particular, the monitoring circuit 16 is configured to operate the battery cells 13 with a reduced load or voltage depending on the specific position P of the defective battery cell 13. P , operate that portion 13a, 13b (here portion 13a) with a reduced load in which the defective battery cell 13 P is arranged.

[0027] The other portion 13a, 13b of battery cells 13 (here portion 13b) can be used to provide a second, predetermined output voltage V2 at the associated voltage converter 14a, 14b (here voltage converter 14b) in order to operate a component 21 of the motor vehicle 10, at least one cooling device 19 of the high-voltage storage unit 11, and / or at least one cooling device 20 of the motor vehicle 10. In addition to supplying the voltage converter 14a, 14b, the second, predetermined output voltage V2 can also be used to directly supply vehicle components 20, 21. This enables, on the one hand, safe operation, in particular of the portion 13a of battery cells 13 in which damage has been detected and located, and on the other hand, allows at least partial supply of other safety-relevant vehicle components and / or the low-voltage system by means of the voltage converter 14b, which can continue to be supplied without impairment.

[0028] In Fig. Figure 2 is a schematic flowchart of a procedure 100 for operating a high-voltage storage device 11 of a motor vehicle 10, exemplified by the high-voltage storage device 11 from Fig. 1, shown.

[0029] In a first step, the high-voltage storage device 11, comprising a cell pack 12 of battery cells 13, is operated to provide a first predetermined output voltage V1 to supply components 20, 21 of the motor vehicle 10 and / or to enable the output voltage V1 to be converted into a low-voltage voltage at at least one voltage converter 14a, 14b of the cell pack 12 or of the high-voltage storage device 11 or of the motor vehicle 10 to supply a low-voltage system of the motor vehicle 10. Here, the high-voltage storage device is in a first state in which the high-voltage storage device 11 is active or current flows (on-state).

[0030] In step b, a fault case of a battery cell 13 isP of the high-voltage storage device 11 or the cell pack 12. The high-voltage storage device 11 remains in its initial state. For example, a cell monitoring device (CSC) can be used as a means 17 to determine a fault in a battery cell 13. P can be used. Upon or as a result of detecting the fault, the high-voltage storage device is, in particular automatically, put into a second state in which the high-voltage storage device 11 is inactive or no current flows (off state). In a further step c, a position P of the faulty battery cell 13 is P in the cell pack 12 or in the high-voltage storage unit 11, in particular using the cell monitoring device as a means 18 to determine a position P of the defective battery cell 13 P , certainly.

[0031] In a further step d, the operation of the high-voltage storage device 11 is controlled, in particular by means of the control unit 15 and / or the monitoring circuit 16, in such a way that the faulty battery cell 13 P and to the faulty battery cell 13 P adjacent further battery cells 13 or the portion 13a of the battery cells 13 in which the defective battery cell 13 PThe remaining battery cells 13, which are positioned as unaffected or assigned to a portion 13b that is unaffected, can be operated or connected to provide power. A second predetermined output voltage V2 is generated or provided by means of the remaining battery cells 13 that are not subjected to a reduced load, in order to operate at least one voltage converter 14a, 14b and / or at least one cooling device 19, 20. This allows the high-voltage storage system to be put into a second state in which only an unaffected portion 13b of battery cells 13 of the high-voltage storage system is active or current flows there (semi-on state). In this third state, for example, if required, a low-voltage system, such as a 12V circuit, of the motor vehicle 10 can be operated, in particular by means of the supply or...operable voltage converter 14b, with a non-critical power output.

[0032] This allows the motor vehicle 10 and / or its components 19, 20, 21 to continue to be supplied with energy even if a portion 13a, 13b of the battery cells 13 of the cell pack 12 of the high-voltage storage unit 11 is not operating or is operating at a reduced capacity. This enables, for example, continuous cooling of the high-voltage storage unit 11. After at least one predetermined criterion is met, the high-voltage storage unit 11 can be switched to a fourth state in which the high-voltage storage unit 11 is permanently deactivated or locked, and the voltage converters 14a, 14b are switched off (off-locked state). This enables the motor vehicle 10 to be parked safely. REFERENCE MARK LIST 10 motor vehicle 11 high-voltage storage units 12-cell pack 13 battery cells 13 P faulty battery cell 13a first share of battery cells 13b second part of battery cells 14a first voltage converter 14b second voltage converter 15 Control unit 16 Monitoring circuit 17 methods for determining a battery cell failure 18 Means of determining the position of the faulty battery cell 19 Cooling device of the high-voltage storage system 20 Cooling system of the motor vehicle 21 Component of the motor vehicle 100 procedures a - d steps P Position V1 first predetermined output voltage V2 second predetermined output voltage

Claims

[1] Method (100) for operating a high-voltage storage device (11) of a motor vehicle (10), comprising the following steps: a) Operating the high-voltage storage device (11) comprising a cell pack (12) of battery cells (13) to provide a first predetermined output voltage (V1); b) Detection of a fault in at least one battery cell (13 P ) of the high-voltage storage (11); c) Determining a position (P) of the faulty battery cell (13 P ) in the cell packing (12); and d) Controlling the operation of the high-voltage storage system (11) such that the faulty battery cell (13) P ) adjacent, further battery cells (13) are at least reduced in load, wherein a second predetermined output voltage (V2) is provided by means of the high-voltage storage (11) to supply at least one voltage converter (14a, 14b) of the cell pack (12). [2] Method (100) according to the preceding claim, wherein the at least one voltage converter (14a, 14b) is used to operate at least one cooling device (19, 20). [3] Method (100) according to one of the preceding claims, wherein the second predetermined output voltage (V2) is used to operate at least one cooling device (19, 20). [4] Method (100) according to any of the preceding claims, wherein the second predetermined output voltage (V2) corresponds to at least half of the first predetermined output voltage (V1). [5] Method (100) according to one of the preceding claims, wherein a first proportion (13a) of the battery cells (13) supplies a first voltage converter (14a) associated with these battery cells (13, 13a), and at least a second proportion (13b) of the battery cells (13) supplies at least one second voltage converter (14b) associated with this second proportion (13b), and the proportion (13a, 13b) of the battery cells (13) in which the defective battery cell (13) P ) is positioned, reducing the load. [6] Method (100) according to the preceding claim, wherein the first part (13a) and the second part (13b) comprise at least substantially the same number of battery cells (13). [7] Method (100) according to one of the five preceding claims, wherein the reduced-load portion (13a, 13b) of the battery cells (13) is used to supply the voltage converter (14a, 14b) associated with this portion (13a, 13b) under at least one predetermined condition. [8] High-voltage storage device (11) for a motor vehicle (10), comprising a cell pack (12) of battery cells (13) for providing a first predetermined output voltage (V1), a first voltage converter (14a) to which a first proportion (13a) of the battery cells (13) is assigned, and at least a second voltage converter (14b) to which at least a further proportion (13b) of the battery cells (13) is assigned, and a monitoring circuit (16), wherein the monitoring circuit (16) is configured to operate at least one of the proportions (13a, 13b) of battery cells (13) with a reduced load and to operate a further proportion (13a, 13b) of battery cells (13) to supply the voltage converter (14a, 14b) assigned to it. [9] High-voltage storage device (10) according to the preceding claim, comprising means (17) for determining a fault case of a battery cell (13) P), means (18) for determining a position (P) of the faulty battery cell (13 P ), and the monitoring circuit (16) is set up, depending on a certain position (P) of the faulty battery cell (13), operate that portion (13a, 13b) with a reduced load in which the faulty battery cell (13 P ) is arranged. [10] High-voltage storage device (11) according to the preceding claim, comprising at least one cooling device (19, 20) which can be supplied by means of the at least one voltage converter (14a, 14b).

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