Method for operating an electrical energy store of a motor vehicle
Patent Information
- Application Number
- PCT/DE2026/100297
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-04-01
- Filing Date
- 2026-03-06
- Publication Date
- 2026-09-17
Smart Images
Figure DE2026100297_17092026_PF_FP_ABST
Abstract
Description
[0001] 24-3042 PIF
[0002] 1
[0003] Method for operating an electrical energy storage device of a motor vehicle
[0004] The invention relates to a method for operating an electrical energy storage device of a motor vehicle.
[0005] US patent 7433794 B1 discloses a method for attenuating the propagation of a thermal event in an energy storage system with a multitude of cells. German patent DE 102021 209141 A1 discloses a method for detecting a short circuit in a semiconductor switching element in an inverter. Furthermore, the
[0006] DE 102022 121 213 A1 a high-voltage energy storage device for a motor vehicle is known to exist.
[0007] The object of the present invention is to provide a method by which a particularly high, especially thermal, safety of an electrical energy storage device of a motor vehicle can be achieved.
[0008] This problem is solved according to the invention by a method having the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.
[0009] The invention relates to a method for operating an electrical energy storage device, a motor vehicle (also referred to simply as a vehicle), preferably a motor car, in particular a passenger car. The method includes an intermediate circuit through which at least one inverter of the motor vehicle can be supplied with electrical energy stored in the electrical energy storage device. For example, the method provides that the motor vehicle has at least one electric machine by means of which the motor vehicle can be driven, in particular purely electrically. Preferably, the electric machine is designed as a high-voltage component whose electrical voltage, in particular its operating or nominal voltage, is preferably greater than 50 V, in particular greater than 60 V, and most preferably several hundred volts.Furthermore, the electrical energy storage device, also referred to as a battery, is preferably a high-voltage component whose electrical voltage, in particular 24-3042 PIF.
[0010] 2
[0011] The electrical operating or nominal voltage is preferably greater than 50 volts (V), particularly greater than 60 V, and most preferably several hundred volts. For example, the electrical energy storage device can provide the electrical energy stored in it, particularly with a direct current voltage, especially via electrical poles of the electrical energy storage device. The electrical energy storage device is, for example, electrically connected or connectable to the electric machine, particularly via power electronics. For example, the electric machine can be supplied via the power electronics with the electrical energy stored in the electrical energy storage device and provided or available from the electrical energy storage device, thereby enabling the electric machine to be operated in motor mode and thus as an electric motor for, in particular, purely electric propulsion of the motor vehicle.It is conceivable that the power electronics include an inverter. Thus, for example, the electrical energy storage device is electrically connected or connectable to the electric machine via the inverter, so that the electric machine can be supplied with the electrical energy stored in and provided by the electrical energy storage device, thereby enabling the electric machine to operate as a motor. The inverter, particularly its power electronics, is electrically connected or connectable to the DC link and can thus be supplied via the DC link with the electrical energy stored in and provided by the electrical energy storage device.In particular, the electrical energy storage device can provide the electrical energy stored within it using the aforementioned direct current or voltage. The inverter can convert the direct current or voltage provided by the electrical energy storage device and supplied to the inverter via the intermediate circuit into alternating current or voltage, particularly three-phase, and provide the alternating current or voltage in such a way that the electrical machine can be supplied or is supplied with the alternating current or voltage provided by the inverter.Thus, for example, the electric machine can be electrically connected to the DC link via the inverter, in particular via the power electronics, so that the electric machine can be supplied with the electrical energy stored in the electrical energy storage device via the DC link. 24-3042 PIF.
[0012] 3
[0013] This allows the electric machine to be operated in the aforementioned motor mode.
[0014] The method identifies a thermal event in the electrical energy storage device. For example, the electrical energy storage device has several storage cells, also known simply as cells, in which the electrical energy, i.e., respective portions of the electrical energy, is stored. The thermal event, for example, is a thermal event in at least or exactly one of the storage cells. In other words, the thermal event occurs in at least or exactly one of the storage cells.The thermal event is, or includes, for example, an increase in the temperature of the electrical energy storage device, also referred to as a temperature rise. The thermal event is determined, for example, by measuring the temperature using a temperature sensor and determining, for example, that the temperature measured by the temperature sensor exceeds a predefined or predetermined temperature value. Alternatively or additionally, the thermal event is determined, for example, by detecting a burnout of the electrical energy storage device, in particular of at least or exactly one storage cell, specifically by measuring the temperature and determining that the temperature exceeds a predetermined temperature value. The thermal event is, or includes, for example, a thermal runaway.Thermal runaway is or comprises overheating of the electrical energy storage device, in particular of at least one or exactly one storage cell, due to a self-reinforcing heat-generating process. The thermal event results, for example, from a short circuit of the electrical energy storage device, in particular of at least one or exactly one storage cell.Alternatively or additionally, the thermal event is determined, for example, by determining at least one, also referred to as a voltage profile, in particular a temporal, electrical voltage profile of the electrical energy storage device, in particular of the at least or exactly one storage cell, and comparing it with a reference profile. If the comparison of the voltage profile with the reference profile reveals that the voltage profile deviates from the reference profile or that a deviation of the voltage profile from the reference profile exceeds a predefined or predetermined point, the thermal event is determined. Alternatively or additionally, the thermal event is determined as a result of determining, in particular recording, at least one change in an insulation value of the electrical energy storage device. Alternatively or additionally, 24-3042 PIF.
[0015] 4
[0016] The thermal event is determined, for example, by measuring the pressure of the electrical energy storage device, particularly within its housing, using a pressure sensor, and comparing the measured pressure to a reference pressure. If the comparison reveals that the pressure exceeds the reference pressure, the thermal event is identified. Alternatively or additionally, the thermal event is determined, for example, by detecting the escape of a hot gas, possibly containing particles, from at least one storage cell.
[0017] In the process, following the detection of the thermal event, a first step of the process, also designated a), is carried out. In this first step, the electrical energy storage device is disconnected from the load, so that no consumer is supplied with electrical energy stored in the device. As a result of the electrical energy storage device being disconnected from the load, for example, no high-voltage voltage exists in the intermediate circuit. For the purposes of this disclosure, "high voltage," and thus "HV," is understood to mean an alternating voltage of more than 30 volts (V) up to a maximum of 1 kV, as well as a direct voltage of more than 60 V up to a maximum of 1.5 kV. Therefore, a high-voltage voltage is understood to mean an alternating voltage of more than 30 V up to a maximum of 1 kV or a direct voltage of more than 60 V up to a maximum of 1.5 kV.As a first step, the electrical energy storage system is de-energized, for example, by opening all available contactors of the electrical energy storage system. This effectively disconnects all high-voltage and low-voltage loads, so that no load, i.e., no device, is supplied with electrical energy stored in the electrical energy storage system.
[0018] As a result of the detection of the thermal event, a second step, also designated b), is carried out in the procedure, whereby the second step is performed after the first step. Thus, the first step is carried out first, followed by the second step. In the second step, the DC link is discharged, thereby at least reducing the electrical voltage in the DC link. The electrical energy storage device is a component of a high-voltage system, also referred to as an HV system, which also includes the DC link. Due to the load disconnection of the electrical energy storage device in the first step, i.e., by opening the contactors, the voltage on the HV system side initially changes.
[0019] 5
[0020] No electrical voltage is present unless the intermediate circuit is discharged, particularly in a controlled manner, which is carried out in the second step. To discharge the intermediate circuit, for example, a resistor, particularly an ohmic resistor, is connected in the intermediate circuit, thereby discharging the intermediate circuit and thus at least reducing, in particular eliminating, the aforementioned electrical voltage in the intermediate circuit, particularly until the intermediate circuit is voltage-free. In other words, it is preferably provided that in the second step the intermediate circuit is discharged in such a way or for such a long time that, or until, the intermediate circuit is voltage-free.
[0021] As a result of the detection of the thermal event, a third step of the procedure, also designated c), is carried out. The first, second, and third steps are steps of the procedure. The third step is carried out after the second step and thus also after the first step, so that first the first step is carried out, then the second step, and then the third step. In the third step of the procedure, at least one DC-DC converter, which is initially deactivated, is activated. This converter is also referred to as the first DC-DC converter. When the term "DC-DC converter" is used below and above, it refers, unless otherwise specified, to the first DC-DC converter.Upon activation of the DC-DC converter, it is supplied with an initial DC voltage from or to the electrical energy storage device. This means that, upon activation, the first DC voltage is applied to the DC-DC converter, provided by or from the electrical energy storage device and, in particular, supplied to the DC-DC converter. The DC-DC converter then converts the initial DC voltage provided by the electrical energy storage device into a second DC voltage, which is lower than the initial DC voltage.In the third step of the process, at least one component of the motor vehicle is operated with the second DC voltage provided by the DC-DC converter, thereby reducing the amount of electrical energy stored in the electrical energy storage device, in particular to the point where the amount of electrical energy stored in the electrical energy storage device is reduced to zero. Thus, in or through the third step of the process, the electrical energy storage device is discharged, in particular completely, thereby eliminating further undesired and from the 24-3042 PIF.
[0022] 6
[0023] Effects resulting from thermal events can be avoided. This allows for a particularly high level of safety, especially thermal safety, of the electrical energy storage system.
[0024] To achieve a particularly high level of safety, especially thermal safety, in the electrical energy storage device, one embodiment of the invention provides that the at least one component includes at least one pump, which is an electric pump, i.e., an electrically operated pump. The pump is operated by the at least one component, and by means of the pump, a preferably liquid coolant is circulated through a cooling circuit, thereby cooling at least a portion of the electrical energy storage device. This allows at least two particularly advantageous functions or effects to be achieved. Firstly, the electrical energy storage device is at least partially discharged by operating the at least one component, and thus the pump, thereby preventing undesirable further effects resulting from the thermal event.Secondly, pre-pumping the coolant advantageously cools the electrical energy storage device, particularly to such an extent that so-called homogenization of the electrical energy storage device can be achieved. This means that at least a substantially uniform temperature of the electrical energy storage device, especially of the storage cells, can be achieved, thereby counteracting thermal events and / or preventing or at least advantageously delaying thermal propagation. Achieving a homogenization time, particularly for a given coolant flow rate that can be achieved by pumping the coolant, can be advantageously designed.In other words, the invention offers a cost-neutral way to both at least partially discharge the electrical energy storage device as a result of the thermal event and to cool the electrical energy storage device particularly advantageously by operating the pump.
[0025] Preferably, the at least one component, in particular the pump, is a low-voltage component whose electrical voltage, in particular operating or nominal voltage, is less than 50 V, in particular at most 48 V, and most preferably less than 20 V. This allows for a particularly high level of safety. 24-3042 PIF
[0026] 7
[0027] It has proven particularly advantageous if the electrical energy storage device comprises at least or exactly two storage modules, namely a first storage module and a second storage module. Preferably, each storage module, considered on its own, is a high-voltage component, also referred to as a high-voltage system or HV system, whose electrical voltage, in particular its operating or nominal voltage, is greater than 50 V, or greater than 60 V, and most preferably several hundred volts. For example, the electrical voltage of each storage module is at least 320 V, in particular at least 350 V, and most particularly at least or exactly 400 V. Thus, for example, each storage module is a 400-volt system. It is conceivable that the electrical energy storage device is designed to connect the storage modules either in parallel or in series with each other.The respective storage module is also referred to as the respective pack, battery pack or battery set.
[0028] The first storage module stores a portion of the electrical energy stored in the electrical energy storage device, and the second storage module stores a portion of the electrical energy stored in the electrical energy storage device. In this method, the storage modules are first electrically connected to each other, in particular by being connected in parallel or in series. The detected thermal event is then assigned to the second storage module, thus determining that the thermal event is a thermal event of the second storage module and not of the first.In other words, the procedure determines that the thermal event, with respect to the storage modules, occurred exclusively on or in the second storage module, so that the thermal event, with respect to the storage modules, is attributed exclusively to the second storage module.
[0029] The method includes, in particular, at least or exactly, two DC-DC converters: the aforementioned first DC-DC converter and a second DC-DC converter. The second DC-DC converter is also referred to as the second DC-DC converter. The first DC-DC converter is, for example, assigned to the first storage module. In the third step (step c), the first DC-DC converter is activated depending on whether the detected thermal event is assigned to the second storage module, so that in the third step the first DC-DC converter is connected to the 24-3042 PIF.
[0030] 8
[0031] The first DC voltage is supplied by or from the first storage module. This means that the first storage module provides the first DC voltage with which the first DC-DC converter is supplied, wherein preferably in the third step, the supply of the first DC-DC converter with an electrical voltage provided by the second storage module is omitted, in particular continuously and thus without interruption.Thus, in the third step of the process, the first DC-DC converter transforms the first DC electrical voltage into the second DC electrical voltage, and in the third step of the process, the first DC-DC converter provides the second DC electrical voltage, with which at least one component is supplied and thereby operated in the third step, thereby reducing the first part and thus the amount of electrical energy stored in the electrical energy storage device.
[0032] The second DC / DC converter, for example, is assigned to the second storage module.
[0033] As a result of the detection of the thermal event and before the third step, the storage modules are electrically separated from each other, i.e., electrically decoupled. This means that, as a result of the thermal event, an intermediate step, also designated z), is carried out, which is performed before the third step c). In this intermediate step (step z), the storage modules, which were initially electrically connected, are electrically disconnected from each other.
[0034] For example, the intermediate step is performed before the third step and after the second step. For example, the intermediate step is performed before the third step, before the second step, and after the first step. For example, the intermediate step is performed before the third step, before the second step (step b)), and before the first step (step a)). Furthermore, it is conceivable that the intermediate step is part of the second step or part of the first step.
[0035] Furthermore, in this embodiment of the invention, it is provided that in the third step (step c)) no consumer is supplied with electrical energy stored in the second storage module via the second DC-DC converter and that during the third step (step c)) the second DC-DC converter is deactivated, in particular continuously and thus without interruption, so that the supply of the second DC-DC converter with electrical energy stored in the second storage module24-3042 PIF
[0036] 9
[0037] stored electrical energy, in particular continuously and therefore without interruption, is avoided.
[0038] Since the thermal event is a thermal event of the second memory module, the second memory module is a so-called affected memory module, which, for example, is no longer intact or no longer exhibits the desired functionality as a result of the thermal event. In contrast, the first memory module, which has not experienced any thermal event, is an intact, unaffected memory module. In this process, the first DC-DC converter, for example, assigned to the unaffected memory module, is activated to at least partially discharge the unaffected first memory module, particularly while the second DC-DC converter, for example, assigned to the affected memory module, is and remains deactivated, and a targeted discharge of the affected second memory module via the second DC-DC converter is, at least initially, prevented.This allows, in particular, the unaffected storage module to be advantageously, and especially completely, discharged. Furthermore, by operating at least one component, especially the pump, both the first and second storage modules can be advantageously cooled. This can, for example, counteract the thermal event at the second storage module, so that the thermal event can be calmed or, in particular, advantageously terminated quickly. Thus, a particularly high level of safety can be achieved.
[0039] To achieve a particularly high level of safety, especially thermal safety, a further embodiment of the invention provides that in the third step, the at least one component is operated at least until the first part is less than a predefinable or predetermined threshold value. Furthermore, it is preferably provided that if the first part is less than the threshold value, i.e., if it is determined that the first part is less than the threshold value, a fourth step, also designated as d), is carried out after the third step (step c)). In the fourth step, the second DC-DC converter, which was deactivated in the third step, is activated, so that the second DC-DC converter is supplied with a third DC voltage from or to the second storage module.In other words, in the fourth step, the second storage module provides the third DC electrical voltage, which is supplied to the second DC voltage converter, thereby making the second DC voltage converter 24-3042 PIF.
[0040] 10
[0041] The third DC voltage is supplied to the second storage module. In other words, the third DC voltage provided by the second storage module is applied to the second DC-DC converter. In the fourth step, the second DC-DC converter transforms the third DC voltage into a fourth DC voltage that is lower than the third DC voltage. In the fourth step (step d)), the second DC-DC converter provides the fourth DC voltage, which supplies and thus operates at least one component and / or another component. This means that in the third step, the second DC voltage is applied to at least one component.In the fourth step (step d)), the fourth DC voltage provided by the second DC-DC converter is applied to at least one component and / or at least one further component, thereby operating the at least one component and / or at least one further component. This, in particular, also reduces the second part and thus the amount of electrical energy stored in the electrical energy storage device. This means that, in particular, the first storage module is at least partially discharged, especially in a targeted manner, and that, especially if the at least one component is or includes the aforementioned pump, the electrical energy storage device is cooled. Subsequently, the second DC-DC converter is activated, so that, in particular, the second storage module is at least partially discharged, especially in a targeted manner.This allows undesirable effects resulting from the thermal event to be avoided or advantageously delayed, thus enabling a particularly high level of safety.
[0042] In a further, particularly advantageous embodiment of the invention, it is provided that in the fourth step (step d)) the first DC voltage converter is activated and thereby supplied with the first DC electrical voltage from or of the first storage module, converts the first DC electrical voltage into the second DC electrical voltage and provides the second DC electrical voltage with which the at least one component is supplied and thereby operated, thereby at least reducing the first part and thus the amount of electrical energy stored in the electrical energy storage device.
[0043] This allows both storage modules to be discharged simultaneously, and in a targeted manner, so that the amount of electrical energy stored in the electrical energy storage system can be advantageously reduced quickly, at least to some extent. Alternatively, 24-3042 PIF
[0044] 11
[0045] It should be provided that in the fourth step (step d)), the first DC-DC converter is deactivated, in particular completely and thus without interruption, so that in the fourth step no load is supplied with electrical energy stored in the first storage module via the first DC-DC converter, and the supply of electrical energy stored in the first storage module to the first DC-DC converter is prevented. This can be particularly advantageous if the first storage module has already been completely discharged by or during the third step. This allows for a particularly high level of safety.
[0046] In particular, energy storage devices, especially the storage modules, are deeply discharged, so that the energy storage device, especially the storage modules, is preferably completely discharged.
[0047] To achieve a particularly high level of safety, a further embodiment of the invention provides that the fourth DC voltage is at most 50 V, in particular less than 50 V, and most preferably at most 48 V. It is more preferably provided that the fourth voltage is less than 48 V, in particular less than 20 V, and most preferably less than 15 V.
[0048] In order to achieve a particularly high level of safety, a further embodiment of the invention provides that in the fourth step no consumer is supplied with an electrical voltage higher than 50 V from or to the electrical energy storage device.
[0049] Another embodiment is characterized in particular by a particularly high level of safety, in that in the fourth step the at least one component and / or the at least one further component is operated at least until the second part is less than a predefinable or predetermined reference value. This allows the second storage module to be discharged in a controlled manner, in particular until only a small amount of electrical energy or no energy at all remains stored in the second storage module.
[0050] In a further, particularly advantageous embodiment of the invention, it is provided that in the fourth step (step d)) the intermediate circuit is monitored with regard to the electrical voltage in the intermediate circuit in such a way that when the 24-3042 PIF
[0051] 12
[0052] If the monitored electrical voltage in the intermediate circuit exceeds a predefined or predetermined threshold, at least one component and / or at least one further component is switched off, so that no consumer is supplied with energy stored in the electrical energy storage device. This allows for a particularly high level of safety.
[0053] In order to achieve a particularly high level of safety, a further embodiment of the invention provides that in the third step (step c)) the intermediate circuit is monitored with regard to the electrical voltage in the intermediate circuit in such a way that, if the monitored electrical voltage in the intermediate circuit exceeds a predefinable or predetermined level value, which may, for example, correspond to the threshold value, at least one component is switched off so that no consumer is supplied with energy stored in the electrical energy storage device.
[0054] Furthermore, it is possible that in the fourth step, at least one component and / or at least one other component is operated, in particular only, for a predefinable or predetermined period of time, whereby after the expiry of this period, the at least one component and / or at least one other component is switched off, i.e., deactivated. Thus, a time-based shutdown condition is provided, which stipulates that when the period beginning with the start of operation of the at least one component and / or at least one other component has expired, the at least one component and / or at least one other component is deactivated, i.e., switched off.
[0055] Another embodiment is characterized in that the second DC electrical voltage is at most 50 V, preferably less than 48 V.
[0056] In particular, it is stipulated that the second DC electrical voltage is less than 48 V, especially less than 20 V and most especially less than 15 V.
[0057] This allows for a particularly high level of safety, especially thermal safety.
[0058] To achieve a particularly high level of safety, a further embodiment of the invention provides that in the third step, no consumer is supplied with an electrical voltage higher than 50 V from or to the electrical energy storage device. 24-3042 PIF
[0059] 13
[0060] Finally, to achieve a particularly high level of safety, it has proven especially advantageous if, in the third step, at least one component is operated until the amount of electrical energy stored in the electrical energy storage device falls below a predefined or predetermined limit. This ensures that, as a result of the third step, only a small amount of electrical energy, or no electrical energy at all, remains stored in the electrical energy storage device, thus enabling a particularly high level of safety.
[0061] Preferably, the at least one component and / or the at least one further component is a low-voltage component whose electrical voltage, in particular electrical operating or nominal voltage, is preferably 12 V, thereby enabling a particularly high level of safety.
[0062] A particular advantage of the invention is that, without having to remove or modify any components, the unaffected storage module is at least partially discharged first, based on the determination of which storage module experienced the thermal event, and then the affected storage module is also at least partially discharged. This allows the entire electrical energy storage system to be advantageously at least partially discharged, thus ensuring a particularly high level of safety.
[0063] Also disclosed is a motor vehicle, which is simply also referred to as a vehicle and is designed for carrying out a method according to the invention. Advantages and advantageous embodiments of the method according to the invention are to be regarded as advantages and advantageous embodiments of the disclosed motor vehicle and vice versa. Preferably, the motor vehicle is a motor car, in particular a passenger car.
[0064] Further details of the invention will become apparent from the following description of a preferred embodiment with the accompanying drawing. Figure 1, the only one in the drawing, shows a schematic representation of an electrical energy storage device and a component of a motor vehicle.
[0065] With reference to the single figure 1, a method for operating an electrical energy storage device 1 of a motor vehicle is described below. This means that the motor vehicle has the electrical energy storage device 1 in which electrical energy is stored. The motor vehicle also has at least one electrical 24-3042 PIF
[0066] 14
[0067] The motor vehicle is powered, in particular, purely electrically. The electrical energy storage device 1 is, for example, a component of a high-voltage system, also known as an HV system. The high-voltage system also includes an intermediate circuit, not shown in detail in Fig. 1. The motor vehicle also has an inverter, not shown in Fig. 1, which can be supplied with the electrical energy stored in the electrical energy storage device 1 via the intermediate circuit.In particular, the electrical energy storage device 1 can provide the electrical energy stored within it at a direct current voltage, wherein the electrical energy that can be provided or is provided by the electrical energy storage device 1 at a direct current voltage can be supplied to the inverter via the intermediate circuit, thereby enabling the inverter to be supplied with the electrical energy from the electrical energy storage device 1, which has a direct current voltage. The inverter is electrically connected or connectable to the intermediate circuit and thus electrically connectable or connected to the electrical energy storage device via the intermediate circuit, so that the inverter can be supplied via the intermediate circuit with the electrical energy stored in and provided by the electrical energy storage device 1, in particular the electrical energy having a direct current voltage.In particular, the electrical energy storage device 1 can provide the electrical energy stored in it with the aforementioned direct voltage or direct current, whereby the direct voltage or direct current that can be provided by the electrical energy storage device 1 can be supplied to the inverter.The inverter can convert the DC voltage or current supplied to it via the intermediate circuit into an AC voltage or current, particularly a three-phase AC voltage or current, and provide this AC voltage or current in such a way that the electric machine can be supplied with the AC voltage or current provided by the inverter, thereby enabling the electric machine to operate as a motor. Thus, the electric machine can be electrically connected to the intermediate circuit via the inverter, allowing it to be supplied with the electrical energy stored in the electrical energy storage device 1 via the inverter and the intermediate circuit.The electric motor allows the motor vehicle to be driven, in particular purely, electrically. 24-3042 PIF.
[0068] 15
[0069] As can be seen from Fig. 1, the electrical energy storage device 1 has at least or exactly two storage modules, namely a first storage module 2 and a second storage module 3. Furthermore, the vehicle has at least or exactly two DC-DC converters, namely a first DC-DC converter 4 and a second DC-DC converter 5. The DC-DC converter 4 is assigned to storage module 2, and the DC-DC converter 5 is assigned to storage module 3. This will be explained in more detail below. The respective DC-DC converter 4, 5 is also referred to as a DC-DC converter. Each storage module 2, 3, considered on its own, is a high-voltage component, also referred to as an HV system or high-voltage system, whose electrical voltage, in particular its operating or nominal voltage, is preferably greater than 50 V, particularly greater than 60 V, and most preferably several hundred volts.The respective high-voltage component is also referred to as the HV component.
[0070] In particular, the electrical energy storage device 1 is configured to selectively connect the storage modules 2 and 3 in series or in parallel with each other. In other words, the electrical energy storage device 1 is preferably configured to selectively connect the storage modules 2 and 3 electrically in such a way that the storage modules 2 and 3 are connected in series with each other, or to connect the storage modules 2 and 3 electrically in such a way that the storage modules 2 and 3 are connected in parallel with each other.
[0071] In the first storage module 2, a first part of the electrical energy stored in the electrical energy storage device 1 is stored, and in the second storage module 3, a second part of the electrical energy stored in the electrical energy storage device 1 is stored.
[0072] In this process, the storage modules 2 and 3 are first electrically connected to each other, such that the storage modules 2 and 3 are connected in series or in parallel to each other.
[0073] The method identifies a thermal event of the electrical energy storage device 1. Furthermore, the method determines on or in which of the storage modules 2 and 3 the thermal event occurred, i.e., whether the thermal event is a thermal event of storage module 2 or a thermal event of storage module 3. In the embodiment illustrated in Fig. 1, the thermal event is assigned to the second storage module 3, so that it is determined that the identified thermal event is located in the storage module 2.
[0074] 16
[0075] The event is a thermal event of the second storage module 3, meaning it occurred on or in the second storage module 3 and not on or in the first storage module 2.
[0076] Following the detection of the thermal event, a first step, also designated a), is performed in which the electrical energy storage device 1 is switched off, so that no consumer is supplied with electrical energy stored in the electrical energy storage device 1. Following the detection of the thermal event, a second step, also designated b), is performed in which the intermediate circuit is discharged, thereby at least reducing the electrical voltage in the intermediate circuit.Following the detection of the thermal event, a third step, also designated c), is performed after the second step. In this third step, depending on whether the detected thermal event is or has been assigned to the second storage module 3, the first DC-DC converter 4 is activated, thereby supplying the first DC-DC converter 4 with a first DC voltage provided by the first storage module 2. In the third step, the first DC-DC converter 4 converts the first DC voltage provided by the storage module 2, with which it is supplied, into a second DC voltage that is lower than the first DC voltage. In the third step, the DC-DC converter 4 provides the second DC voltage, with which at least one component 6 of the motor vehicle is supplied and thereby operated.By operating at least one component 6, the first part, and thus the amount of electrical energy stored in the energy storage device 1, is at least reduced. Furthermore, it is provided that, as a result of the detection of the thermal event, an intermediate step, also designated z), is carried out, which is performed before the third step. In this intermediate step, the storage modules 2 and 3, which are initially electrically connected, are electrically disconnected from each other. The intermediate step is performed, for example, before the third step and after the second step. It is also conceivable that the intermediate step is performed before the third step, before the second step, and after the first step.Furthermore, it is conceivable that the intermediate step is performed before the third step, before the second step, and before the first step as a result of detecting the thermal event. Overall, the intermediate step is performed as a result of detecting the thermal event. It is also intended that no load is connected via the second DC-DC converter 524-3042 PIF during the third step (step c)).
[0077] 17
[0078] The second storage module 3 is supplied with electrical energy stored in it, and in the third step (step c)), the second DC-DC converter 5 is deactivated, so that the second DC-DC converter 5 is not supplied with electrical energy stored in the second storage module 3. Furthermore, it is provided that in the third step, the first DC-DC converter 4 is not supplied with electrical energy stored in the second storage module 3, so that in the third step, the DC-DC converter 4 is supplied with the first electrical DC voltage exclusively from storage module 2, with respect to storage modules 2 and 3. In particular, it is provided that in the third step, the provision of electrical energy by storage module 3 is prevented, especially continuously and thus without interruption.
[0079] It is also evident that the process determines which of the storage modules 2 and 3 are affected, that is, in or on which of the storage modules 2 and 3 the thermal event occurred. As a result of the initial determination of the thermal event and its assignment to storage module 3, storage module 2 is, in particular, at least partially discharged. This occurs when the DC-DC converter 4 is activated, supplied with the first DC voltage from or within storage module 2, and converts this first DC voltage into a second DC voltage. The second DC voltage is then supplied to and thus operates component 6. In this way, component 6 is supplied with the electrical energy stored in storage module 2.In particular, it is intended that in the third step, the operation of component 6 with electrical energy stored in the storage module 3 will not take place.
[0080] Preferably, in the third step, the at least one component 6 is operated until the first part is less than a predefinable or predetermined threshold value. If the first part is less than the threshold value, a fourth step of the method is carried out after the third step (step c)), the fourth step also being designated d). In the fourth step, the second DC-DC converter 5 is activated, so that in the fourth step the storage module 3 provides a third DC voltage with which the DC-DC converter 5 is supplied. In the fourth step, the DC-DC converter 5 converts the third DC voltage provided by the storage module 3 into a fourth DC voltage, which is less than the 24-3042 PIF
[0081] 18
[0082] The third DC voltage is supplied. In the fourth step, the DC-DC converter 5 provides the fourth DC voltage, which supplies and operates at least one component 6 and / or at least one further component of the motor vehicle, thereby reducing the second part stored in the storage module 3 and thus the amount of electrical energy stored in the electrical energy storage device 1. Thus, in the fourth step, the storage module 3 is specifically discharged.
[0083] Preferably, component 6 is or comprises a pump, which is operated by operating component 6. Operating the pump circulates a preferably liquid coolant through a cooling circuit, thereby cooling at least a portion of the electrical energy storage device 1. Preferably, this portion of the electrical energy storage device 1 comprises the storage modules 2 and 3, so that the storage modules 2 and 3 are preferably cooled by circulating the coolant. This can counteract thermal events and / or advantageously bring thermal events to an early end, thus ensuring a particularly high level of safety.
[0084] In particular, by cooling at least the sub-area of the electrical energy storage device 1, a homogenization of the electrical energy storage device 1 can be achieved, so that, for example, the storage modules 2 and 3, in particular their storage cells, have at least an essentially the same or uniform temperature or temperature distribution.
[0085] Preferably, in the third and / or fourth step, the intermediate circuit is monitored with respect to the electrical voltage in the intermediate circuit such that, if the monitored electrical voltage in the intermediate circuit exceeds a predefinable or predetermined threshold value, at least one component 6 and / or at least one further component is switched off, so that no consumer is supplied with electrical energy stored in the electrical energy storage device 1. This allows for a particularly high level of safety. -3042 PIF
[0086] 19
[0087] Reference symbol list
[0088] electrical energy storage first storage module
[0089] second memory module
[0090] first DC-DC converter second DC-DC converter component
Claims
1. 24-3042 PIF 20 Patent claims 1. Method for operating an electrical energy storage device (1) of a motor vehicle, wherein: - an intermediate circuit is provided, via which at least one inverter can be supplied with electrical energy stored in the electrical energy storage device (1); - a thermal event of the electrical energy storage device (1) is determined; - as a result of determining the thermal event: a) the electrical energy storage device (1) is switched off without load, so that no consumer is supplied with electrical energy stored in the electrical energy storage device (1); b) after step a): the intermediate circuit is discharged, thereby at least reducing the electrical voltage in the intermediate circuit; c) after step b): at least one DC voltage converter (4) is activated, which is thereby supplied with a first DC electrical voltage from the electrical energy storage device (1), converts the first DC electrical voltage into a second DC electrical voltage which is lower than the first DC electrical voltage and provides the second DC electrical voltage with which at least one component (6) is supplied and thereby operated, thereby reducing at least some of the electrical energy stored in the electrical energy storage device (1).
2. Method according to claim 1, characterized by the fact that the at least one component (6) comprising at least one pump by means of which, by operating the pump, a coolant is conveyed through a cooling circuit, thereby cooling at least a part of the electrical energy storage device (1).24-3042 PIF 21 3. Method according to claim 1 or 2, characterized by the fact that: - the electrical energy storage device (1) has at least two storage modules (2, 3), namely a first storage module (2) in which a first part of the electrical energy stored in the electrical energy storage device (1) is stored, and a second storage module (3) in which a second part of the electrical energy stored in the electrical energy storage device (1) is stored; - the storage modules (2, 3) are initially electrically connected to each other: - the determined thermal event is assigned to the second storage module (3); - two DC voltage converters (4, 5) are provided, namely: o a first DC-DC converter (4), which is activated at step c) depending on the fact that the determined thermal event is assigned to the second storage module (3), so that at step c) the first DC-DC converter (4) is supplied with the first DC electrical voltage from the first storage module (2), converts the first DC electrical voltage into the second DC electrical voltage and provides the second DC electrical voltage with which the at least one component (6) is supplied and thereby operated, thereby at least reducing the first part and thus the amount of electrical energy stored in the electrical energy storage device (1); and o a second DC-DC converter (5); - as a result of the detection of the thermal event and before step c): the storage modules (2, 3) are electrically disconnected from each other; and - at step c): o no consumer is supplied via the second DC-DC converter (5) with electrical energy stored in the second storage module (3); and o the second DC voltage converter (5) is deactivated, so that the second DC voltage converter (5) is not supplied with electrical energy stored in the second storage module (3).
4. Method according to claim 3, characterized by the fact that: 24-3042 PIF 22 - in step c) at least component (6) is operated at least until the first part is less than a predefinable or predetermined threshold; and - if the first part is less than the threshold, after step c) a step d) is carried out in which the second DC voltage converter (5) is activated, so that the second DC voltage converter (5) is supplied with a third electrical DC voltage from the second storage module (3), converts the third electrical DC voltage into a fourth electrical DC voltage which is lower than the third electrical DC voltage and provides the fourth electrical DC voltage with which the at least one component (6) and / or at least one further component is supplied and thereby operated, thereby at least reducing the second part and thereby the amount of electrical energy stored in the electrical energy storage device (1).
5. Method according to claim 4, characterized by the fact that: - in step d) the first DC-DC converter (4) is activated and thereby supplied with the first DC voltage from the first storage module (2), converts the first DC voltage into the second DC voltage and provides the second DC voltage with which the at least one component (6) is supplied and thereby operated, thereby at least reducing the first part and thus the amount of electrical energy stored in the electrical energy storage device (1); or - in step d) the first DC-DC converter (4) is deactivated, so that no consumer is supplied via the first DC-DC converter (4) with electrical energy stored in the first storage module (2) and the supply of electrical energy to the first DC-DC converter (4) with electrical energy stored in the first storage module (2) is prevented.
6. Method according to claim 4 or 5, characterized by the fact that The fourth DC voltage is at most 50 volts. 24-3042 PIF 23 7. Method according to any one of claims 4 to 6, characterized by the fact that in step d) no consumer is supplied with an electrical voltage higher than 50 volts by the electrical energy storage device (1).
8. Method according to any one of claims 4 to 7, characterized by the fact that in step d) the at least one component (6) and / or the at least one further component is operated at least until the second part is less than a predefinable or predetermined reference value.
9. Method according to any one of claims 4 to 8, characterized by the fact that In step d) the intermediate circuit is monitored with respect to the electrical voltage in the intermediate circuit in such a way that, when the monitored electrical voltage in the intermediate circuit exceeds a predefinable or predetermined threshold value, at least one component (6) and / or at least one further component is switched off, so that no consumer is supplied with electrical energy stored in the electrical energy storage device (1).
10. Method according to any one of the preceding claims, characterized by the fact that In step c) the intermediate circuit is monitored with respect to the electrical voltage in the intermediate circuit in such a way that, if the monitored electrical voltage in the intermediate circuit exceeds a predefinable or predetermined level value, at least one component (6) is switched off so that no consumer is supplied with energy stored in the electrical energy storage device (1).
11. Method according to any of the preceding claims, characterized by the fact that the second DC electrical voltage is at most 50 volts.
12. Method according to any one of the preceding claims, characterized by the fact that 24-3042 PIF 24 in step c) no consumer is supplied with an electrical voltage higher than 50 volts by the electrical energy storage device (1).
13. Method according to any one of the preceding claims, characterized by the fact that in step c) at least one component (6) is operated at least until the quantity is less than a predeterminable or predetermined limit.