DE102016000318B4 - Method for the electrical preconditioning of a passenger compartment of a vehicle - Google Patents

Abstract

Method for electrical preconditioning of a passenger compartment of a vehicle, in which a battery of the vehicle is connected to a stationary charging infrastructure with a given charging power for charging and the preconditioning ends at a preset starting time (t0) or at least a lead time (VL) of the preconditioning should have expired The following steps are provided: - Determination of a wake-up time (ts) for the start of pre-air conditioning, from which the power for pre-air conditioning is taken from the charging infrastructure, - Continuous determination of the usable power (LLade) from the charging infrastructure, - Continuous determination of the usable battery energy (Wbatt) of the battery, - Determination of a maximum possible runtime (Tmax), which is sufficient for pre-air conditioning when using the determined usable battery energy (Wbatt) by dividing the value of the usable battery energy (Wbatt) by one of the power The specified power cap value (LD), which limits the consumption for the pre-air conditioning, is divided, and - Determination of a switchover time (t1) from which, in addition to the energy from the charging infrastructure, an energy limited to the power cap value (LD) is taken from the battery for pre-air conditioning, whereby the switchover time (t1) is determined in such a way that the remaining time (TR) starting from the start time (t0) up to this switchover time (t1) is less than the maximum possible running time (Tmax).

Description

The invention relates to a method for the electrical preconditioning of a passenger compartment of a vehicle, in which a battery of the vehicle is connected for charging to a stationary charging infrastructure with a given charging power.

In order to be able to optimally regulate the temperature of vehicles that are at a standstill, it is known, for example, for hybrid vehicles, to use the energy required to operate an air conditioning system for heating or cooling the vehicle interior from the existing electrical energy stores. So describes the DE 10 2005 004 950 A1 an air conditioning system for a hybrid vehicle, in which the preconditioning is carried out by means of an electric refrigerant compressor integrated into the air conditioning system. The disadvantage of this, however, is that, due to the limited storage capacities of the electrical storage, preconditioning is only possible for a limited period of time.

From the DE 10 2011 079 415 A1 a method for charging an electric vehicle with an electrical energy store and for stationary air conditioning of the vehicle interior by means of an electric air conditioning system is known. According to this method, the electrical energy store is charged to a minimum state of charge. After the minimum charge state of the energy store has been reached, the interior is air-conditioned in such a way that a predetermined air-conditioning state of the interior is reached at an assumed departure time. The energy store is charged to a target state of charge with excess energy that is not required to achieve the air conditioning state.

In a method for preconditioning a passenger compartment of a vehicle, according to FIG DE 10 2009 053 649 A1 at least one component of an air conditioning system of the vehicle is supplied with electrical energy. Here, the at least one component of the air conditioning system is put into operation when electrical energy is fed into a power network of the vehicle by means of a power supply device external to the vehicle.

From the DE 10 2013 215 473 A1 A further method is known for regulating an auxiliary air conditioning system for a vehicle that includes at least one first energy source. In this method, an actual value of a climate parameter is determined from the interior of the parked vehicle and a difference value is formed from the actual value and a reference value. Furthermore, a probable time of use of the vehicle is determined, a time interval being determined from the instantaneous time and the determined probable time of use. Depending on the length of the time interval and the difference value, an amount of energy required for regulating to a target value of the climate parameter is determined and, depending on the required amount of energy and the amount of energy available from the first energy source, the actual value of the climate parameter is determined within the time interval regulated the target value.

From the DE 10 2009 038 431 A1 a method is known in which a user of an electric or hybrid vehicle connected to a charging infrastructure predetermines an expected departure time and a charging process and an air conditioning system are automatically controlled as a function of the expected departure time. The presetting of the expected departure time takes place either through a direct operator input by the user in the vehicle or through a remote setting using a mobile terminal device, such as a cell phone.

Furthermore, in this DE 10 2009 038 431 A1 suggested that the air conditioning system of the vehicle can be controlled or adjusted directly by the user. In addition, it should be made possible, in the event of a short-term departure decision, to air-condition the vehicle with energy from the charging infrastructure via the remote setting, which is why no energy from the vehicle's electrical energy storage devices has to be used.

If the energy for the pre-air conditioning is taken exclusively from the charging infrastructure, depending on the charging power, especially if this is very low, there is a risk that the desired air conditioning status will not be achieved in the vehicle at the time of departure.

It is therefore the object of the invention to provide an improved method for preconditioning a vehicle connected to a charging infrastructure, in particular a hybrid vehicle. In this way, the maximum possible comfort with regard to the air conditioning status in the vehicle should be achieved at the time of an expected departure date. Furthermore, with an immediate start of the preconditioning, a high level of air conditioning comfort should be achieved in the shortest possible time on the basis of a current departure decision by the user.

This object is achieved by a method with the features of patent claim 1 and with the features of patent claim 3.

A vehicle in which the method described with reference to the figures for electrical preconditioning of a passenger compartment for Can be used, is designed as a hybrid vehicle and connected, for example, via a charging cable to a charging infrastructure or charging station with a given charging power as an external electrical energy supply.

With electrical pre-air conditioning, the vehicle's passenger compartment is cooled, ventilated or heated before departure. The time of the start of the preconditioning is therefore before such a departure time. The cooling or heating output required for pre-air conditioning is generated, for example, with an electric air conditioning compressor or, for example, an electric heater or a heat pump. The time of the start of the pre-air conditioning can be determined as a function of the departure time, for example by timer programming, and is therefore also referred to below as departure-time-based pre-air conditioning. It is also possible to start the preconditioning at a current point in time (immediate start).

If the charging capacity of the charging infrastructure is sufficiently high, the energy for the pre-air conditioning is taken exclusively from the charging infrastructure. In the other case, if the charging power is too low, no preconditioning is carried out on the basis of pure charging power, but the method according to the invention described below is carried out in which the battery is discharged in favor of the preconditioning.

• - Ermittlung eines Weckzeitpunktes für den Beginn der Vorklimatisierung, ab welchem die Leistung für die Vorklimatisierung aus der Ladeinfrastruktur entnommen wird,
• - kontinuierliche Ermittlung der nutzbaren Leistung aus der Ladeinfrastruktur
• - kontinuierliche Ermittlung der nutzbaren Batterieenergie der Batterie,
• - Bestimmung einer maximal möglichen Laufzeitdauer, die bei einer Nutzung der ermittelten nutzbaren Batterieenergie für die Vorklimatisierung ausreicht, indem der Wert der nutzbaren Batterieenergie durch einen den Leistungsverbrauch für die Vorklimatisierung begrenzenden und vorgegebenen Leistungsdeckelwert dividiert wird, und
• - Bestimmung eines Umschaltzeitpunktes, ab welchem für die Vorklimatisierung zusätzlich zur Energie aus der Ladeinfrastruktur eine auf den Leistungsdeckelwert begrenzte Energie aus der Batterie entnommen wird, wobei der Umschaltzeitpunkt derart bestimmt ist, dass die Restzeitdauer ausgehend von dem Startzeitpunkt bis zu diesem Umschaltzeitpunkt kleiner als die maximal mögliche Laufzeitdauer ist, die mit der elektrischen Energie aus der Batterie erzielt werden kann.

In the method for electrical preconditioning of a passenger compartment of a vehicle according to the first-mentioned solution, in which a battery of the vehicle for charging is connected to a stationary charging infrastructure with a given charging power and the preconditioning should end at a preset starting time or at least a lead time of the preconditioning should have expired , the following steps are planned:

• - Determination of a wake-up time for the start of the preconditioning, from which the power for the preconditioning is taken from the charging infrastructure,
• - Continuous determination of the usable power from the charging infrastructure
• - continuous determination of the usable battery energy of the battery,
• - Determination of a maximum possible runtime that is sufficient when using the determined usable battery energy for pre-air conditioning by dividing the value of the usable battery energy by a predetermined power cap value that limits the power consumption for pre-air conditioning, and
• - Determination of a switching point in time from which, in addition to energy from the charging infrastructure, energy limited to the power cap value is drawn from the battery for pre-air conditioning, the switching point being determined in such a way that the remaining time, starting from the starting point up to this switching point, is less than the maximum is the possible running time that can be achieved with the electrical energy from the battery.

With this method according to the invention, it is therefore permissible for the battery connected to the charging infrastructure to be discharged in favor of pre-air conditioning.

Based on the situation that the charging capacity of the charging infrastructure is too low (therefore a continuous determination of the usable capacity from the charging infrastructure takes place) in order to carry out the pre-air conditioning exclusively on the basis of this and a preset starting time t0 for the departure-time-based pre-air conditioning should be a maximum possible run time for a preliminary phase during which the pre-air conditioning is carried out with the battery energy of the battery and the power from the charging infrastructure.

The determination of a maximum possible duration for the lead phase VL of the pre-air conditioning for the departure-time-based pre-air conditioning is calculated continuously. First of all, a power cap value LD intended for pre-air conditioning must be determined based on the ambient temperature Utemp. A power cap value LD is therefore specified so that there is an upper limit for the power consumption for the preconditioning and thus a certain running time can be guaranteed while maintaining this power consumption. The possible running time Tmax must be determined continuously, since depending on the performance of the charging infrastructure and the actual power consumption for the pre-air conditioning during pre-air conditioning, which takes place exclusively via the charging power, the energy content of the battery can change during this time. For example, with a usable energy Wbatt of 1700 Wh, an ambient temperature Utemp of -5 ° C and a power cap value LD of 5 kW according to the formula: Tmax = Wbatt / LD, a maximum possible running time for a lead phase VL for the pre-air conditioning of 20 min, with a power cap value of 3.5 kW, a maximum possible running time for a lead phase VL of about 29 min. During such a lead phase VL, the energy required for this is drawn from the battery and the charging infrastructure. Is the vehicle on none If the charging infrastructure is connected, the energy is taken exclusively from the battery.

With this method according to the invention, an optimal switching time is determined at which a switch is made from pure use of the power from the charging infrastructure for pre-air conditioning to using the energy from the battery and the power from the charging infrastructure for pre-air conditioning of the vehicle interior with a maximum specified power cap if a charging capacity is available from the charging infrastructure that makes it worthwhile to carry out preconditioning. This switching point in time is determined in such a way that from this point in time the electrical power available for pre-air conditioning can be increased to the specified power cap value and with this power, which can be higher than the power from the charging infrastructure, up to the preset start time, which is set in usually corresponds to the departure time planned by the user, the vehicle is preconditioned, ie that either the preconditioning or a preconditioning phase of the preconditioning is ended at this starting point, and the preconditioning phase can be followed by a follow-up phase of the preconditioning. A separate power cover can be provided for the delay time. In order to ensure the maximum possible air conditioning comfort for the user at the self-set starting time, the vehicle's battery, in this case the battery of a hybrid vehicle, is discharged in favor of pre-air conditioning in the event of a low charging capacity of the charging infrastructure. In the case of a hybrid vehicle, despite a battery that is not fully charged, mobility is ensured by its conventional drive (combustion engine). In the ideal case, the charging power from the charging infrastructure is equal to or greater than the specified power cap value or equal to or greater than the real consumption for pre-air conditioning.

According to an advantageous development of the invention, the wake-up time is determined at least as a function of the ambient temperature and / or the interior temperature of the vehicle.

• - Entnahme der Energie für die Vorklimatisierung aus der Batterie und der Ladeinfrastruktur, wobei die entnommene Leistung auf einen vorgegebenen Leistungsdeckelwert begrenzt wird,
• - laufende Ermittlung der nutzbaren Batterieenergie der Batterie, und
• - Bestimmung eines Umschaltzeitpunktes, ab welchem die Energie für die Vorklimatisierung ausschließlich aus der Ladeinfrastruktur entnommen wird, wobei der Umschaltzeitpunkt derart bestimmt ist, dass im Umschaltzeitpunkt die nutzbare Batterieenergie kleiner als ein erster Schwellwert ist.

In the method for electrical preconditioning of a passenger compartment of a vehicle according to the second-mentioned solution, in which a battery of the vehicle is connected for charging to a stationary charging infrastructure with a given charging power and the preconditioning is started at a current point in time, the following steps are provided:

• - Extraction of the energy for the pre-air conditioning from the battery and the charging infrastructure, whereby the extracted power is limited to a specified power cap value,
• - ongoing determination of the usable battery energy of the battery, and
• - Determination of a switchover point from which the energy for the pre-air conditioning is taken exclusively from the charging infrastructure, the switchover point being determined in such a way that the usable battery energy is less than a first threshold value at the switch point.

In this second-mentioned method according to the invention, the pre-air conditioning is started at a current point in time by the user. In such a case, either no preset start time has been specified by the user or the user has opted for a departure time that is earlier than a preset start time. In order to achieve the desired air conditioning comfort in the vehicle interior as quickly as possible in such a case, according to this second method according to the invention, the pre-air conditioning is carried out at the current point in time with energy from the battery and the charging infrastructure with a power cap value until the energy from the battery defines a switching point in time falls below. From this point in time, the pre-air conditioning will continue to run exclusively with energy from the charging infrastructure. In this second-mentioned method according to the invention, the preconditioning is initially carried out with the maximum possible energy from the battery of the vehicle and the charging infrastructure, before the preconditioning is then continued at the switchover time with energy supplied by the charging power of the infrastructure. In the ideal case, the power from the charging infrastructure is equal to or greater than the specified power cap value or equal to or greater than the real requirement for pre-air conditioning.

According to an advantageous embodiment of the invention in accordance with the second-mentioned solution, the pre-air conditioning supplied with energy from the battery is interrupted when the usable battery energy has fallen below a second threshold value. This is particularly intended to avoid deep discharge of the vehicle's battery.

The methods according to the invention are particularly suitable when the charging power of the charging infrastructure is less than the power cap value specified for the pre-air conditioning or less than the power required for the pre-air conditioning. According to a further development, the level of the power cap value is determined as a function of the outside temperature of the vehicle and / or the interior temperature of the vehicle. The definition of such a power cap value for the pre-air conditioning allows the determination of the maximum runtime, ie the duration of pre-air conditioning with guaranteed performance.

• 1 eine Wertetabelle zur Bestimmung des Leistungsdeckels in Abhängigkeit von der Umgebungstemperatur,
• 2 ein Zeit-Leistungsdiagramm zur Darstellung eines optimalen Ablaufes einer Vorklimatisierung im Falle eines voreingestellten Startzeitpunktes für die Vorklimatisierung,
• 3 ein Zeit-Leistungsdiagramm nach 2 zur Ermittlung eines Umschaltzeitpunktes im Falle eines vorangestellten Startzeitpunktes für die Vorklimatisierung gemäß des Verfahrens,
• 4 ein Zeit-Leistungsdiagramm zur Darstellung eines optimalen Ablaufes einer Vorklimatisierung im Falle eines Sofortstartes der Vorklimatisierung, und
• 5 ein Zeit-Leistungsdiagramm nach 4 zur Ermittlung eines Umschaltzeitpunktes im Falle eines Sofortstartes der Vorklimatisierung.

The invention is described in detail below on the basis of exemplary embodiments with reference to the accompanying figures. Show it:

• 1 a table of values to determine the power cover depending on the ambient temperature,
• 2 a time-performance diagram to show an optimal sequence of preconditioning in the case of a preset starting time for preconditioning,
• 3 a time-performance diagram according to 2 to determine a switchover time in the case of a preceding starting time for pre-air conditioning according to the procedure,
• 4th a time-performance diagram to illustrate an optimal sequence of preconditioning in the event of an immediate start of preconditioning, and
• 5 a time-performance diagram according to 4th to determine a changeover point in the event of an immediate start of the preconditioning.

The threshold value for the charging power, up to which the pre-air conditioning is carried out exclusively on the basis of the charging power of the charging infrastructure, is determined as a function of the ambient temperature of the vehicle. Such a charging power threshold can be, for example, 2.5 kW at an ambient temperature of -10 ° C. If the charging power is below this threshold (e.g. 2 kW), preconditioning based solely on the power of the charging infrastructure is not carried out. In such a case, the duration T _{Max is} limited to T _before . Here the duration T _{Max is} off 1 decisive, which contains sample values for T _Max . These values should be applicable. Any number of support points can be provided for the amount of energy. Several support points for the ambient temperature are also possible. T _Max depends on the ambient temperature and the usable amount of energy in the battery. If the amount of energy in the battery is too low and the power from the charging infrastructure is too low, preconditioning is not carried out. A minimum permissible time period for T _Max can be specified.

The sequence of an associated preconditioning is shown in the time-performance diagram 2 shown. In this diagram, the start time t ₀ = 0 the preset by the user of the vehicle starting time t _0. This start time t ₀ is determined as a direct operation input by the user in the vehicle or via a remote setting by means of a mobile terminal.

First, a wake-up time t _{s is determined} as the start of the pre-air conditioning, with only the charging power L _Lade of 3.2 KW being used for the pre-air conditioning.

If the maximum possible duration Tmax of z. B. 20 min is divided into the lead phase VL and a lag phase NL, the lead phase VL is ended at the starting time t _{0 and} the lag phase NL follows. If this maximum possible running time Tmax is divided into equal time segments, the lead phase VL and the lag phase NL each last 10 minutes.To ensure that the lead phase VL ends at the start time t ₀ , it must start at the switchover time t ₁ , i.e. at -10 min. The preliminary phase VL of the preconditioning can be carried out with full power from the battery and the charging infrastructure up to the power cap value L _D of 5 kW. Before this switchover time t ₁ , starting with the wake-up time t _s, the energy for the preconditioning is from the charging infrastructure with a charging power L _charging of z. B. 3.2 kW removed. This preconditioning phase based on the charging power is in 2 labeled B.

The lower charging power _batt against the limited to the power cap value L _D W L battery power _charging from the charging infrastructure would not be sufficient in this example alone for preconditioning.

In order to determine the optimal switchover time t ₁ , in which a switch is made from pre-air conditioning with a charging power L _Charge of 3.2 kW to the pre-air phase VL of pre-air conditioning with maximum power from the battery and the charging infrastructure, limited only by a power cap value of 5 kW , is shown below using the time-performance diagram 3 explained.

On the basis of a preset starting time t ₀ , the wake-up time t _s is first determined, from which the preconditioning begins with phase B on the basis of the charging infrastructure with a charging power L _charging of 3.2 kW.

die maximal mögliche Laufzeitdauer T_max für die Vorlaufphase VL aus den Größen der verfügbaren Batterieenergie W_batt und dem Leistungsdeckelwert L_D bestimmt.From this wake-up time t _s , the usable energy W _{batt of} the battery is continuously determined and using the formula $${\text{T}}_{\text{Max}}{\text{= W}}_{\text{batt}}{\text{/ L}}_{\text{D.}}$$

the maximum possible running time T _max for the lead phase VL is determined from the sizes of the available battery _energy W _batt and the power _{cap value} L _D.

By means of this maximum possible running time Tmax for the lead phase VL and the Remaining time T _R up to the start time t ₀ , the optimum switchover time t _{1 is} determined. For this purpose, this remaining time T _R is continuously compared with the maximum possible running time Tmax at time t ₀ -T _R. If the available battery _energy W _{batt is} low, the calculated maximum possible running time T _max can initially be less than the remaining time T _R. However, the more the point in time t ₀ -T _R migrates in the direction of the starting point in time t ₀ , the remaining duration T _R becomes shorter and the duration Tmax falls below the specified point in time, called the switchover point in time t ₁ .

dieser Umschaltzeitpunkt t₁ definiert, in welchem von dem Vorklimatisierungsbetrieb B auf Basis der Ladeleistung L_Lade auf die Vorlaufphase VL der Vorklimatisierung mit 5 kW elektrischer Leistung aus der Batterie und Ladeinfrastruktur umgeschaltet wird. Ab diesem Umschaltzeitpunkt t₁ kann die Vorklimatisierung mit der durch den Leistungsdeckelwert L_D begrenzten Leistung aus der Batterie und aus der Ladeinfrastruktur bis zum Startzeitpunkt t₀ durchgeführt werden, da die entsprechende Energie komplett in der Batterie vorliegt und damit keine Abhängigkeit von der von der Ladeinfrastruktur gelieferten Ladeleistung besteht.Thus, with the fulfillment of the condition $${\text{T}}_{\text{R.}}{\text{<T}}_{\text{Max}}$$

this switchover point in time t ₁ defines at which the pre-air conditioning operation B based on the charging power L _Charge to the pre-air conditioning phase VL with 5 kW electrical power from the battery and charging infrastructure is switched over. From this switchover time t ₁ , pre-air conditioning can be carried out with the power from the battery and from the charging infrastructure limited by the power cap value L _D up to the starting time t ₀ , since the corresponding energy is completely in the battery and is therefore not dependent on the charging infrastructure delivered charging power.

In the illustrated case according to 3 The lead time VL corresponds to the maximum possible run time Tmax.

It is also according to from 2 It is possible to divide the maximum possible duration Tmax into a lead phase VL and a lag phase NL, for example with the ratio 50:50, whereby the switchover time t _{1 changes} from the time -Tmax in the direction of the starting time t ₀ to the time - Tmax / 2 shifts. The follow-up time NL then ends at time t ₂ = T _max / 2.

The preconditioning of the vehicle connected to a charging infrastructure can also be started by the user at a current point in time t _akt (immediate start). In such a case, either no preset starting time t ₀ was specified by the user or the user has opted for a departure time that is earlier than a preset starting time t ₀ . In order to still produce the desired air conditioning comfort in the vehicle interior as quickly as possible in such a case, the pre-air conditioning is carried out at the current time t _act with energy from the battery and the charging infrastructure with a power cap value.

As an example, this method should be based on the time-performance diagram 4th explained. At an ambient temperature of Utemp of -5 ° C, the output cap value L _{D is} 5 kW. So that according to 4th the switchover time t ₃ , at which a switch is made from full power, taking into account the power cap to the limitation of power consumption, to the charging power L _{charging of} 3.2 kW. If a switchover occurs, the power consumption for pre-air conditioning is limited to the capacity of the charging infrastructure and carried out up to a maximum time t _e .

The determination of the optimal switchover time t ₃ , at which the energy supply of the preliminary phase VL of the preconditioning is switched from the battery and the power of the charging infrastructure with a power limited by the power cap value L _D of 5 kW to the charging infrastructure with a charging power of 3.2 kW , is shown below using the time-performance diagram 5 explained.

At the start of the current point in time t _akt , the usable energy W _{batt of} the battery is continuously determined and compared with a first threshold value x ₁ Wh.

Once the condition

erfüllt ist, also die nutzbare Energie W_batt mit einem Leistungsdeckelwert L_D von 5 kW kleiner als der erste Schwellwert x₁Wh ist, wird auf die Ladeleistung L_Lade von z.B. 3,2 kW aus der Ladeinfrastruktur für die weitere Vorklimatisierungsphase N umgeschaltet, die dann im Zeitpunkt t_e endet. $${\text{W.}}_{\text{batt}}<{\text{x}}_1\text{Wh}$$

is fulfilled, _i.e. the usable energy W _batt with a power _{cap value} L _D of 5 kW is less than the first threshold value x ₁ Wh, the charging power L _Charge of, for example, 3.2 kW from the charging infrastructure for the further preconditioning phase N is switched to then ends at time t _e .

When the energy W _batt that can be used from the battery _{falls below} the first threshold value x ₁ Wh, this switching time t _{3 is} defined. From this point in time, the pre-air conditioning with limited power of z. B. 3.2 kW continued from the charging infrastructure. In this method, the pre-air conditioning is initially carried out with the maximum possible energy from the battery and the charging infrastructure of the vehicle, before the pre-air conditioning phase N is then continued at switchover time t ₃ with an energy supplied by the charging power L _{charging of} the charging infrastructure. During this preconditioning phase N, the battery is not charged (so-called zero current regulation phase)

However, if the energy W _batt that can be used from the battery _falls below a second threshold value x ₂ Wh, the preconditioning is canceled. This is particularly intended to avoid deep discharge of the vehicle's battery.

Claims (6)

Method for electrical preconditioning of a passenger compartment of a vehicle, in which a battery of the vehicle is connected to a stationary charging infrastructure with a given charging power for charging and the preconditioning ends at a preset starting time (t ₀ ) or at least a lead time (VL) of the preconditioning has expired The following steps are provided: - Determination of a wake-up time (t _s ) for the start of pre-air conditioning, from which the power for pre-air conditioning is taken from the charging infrastructure, - Continuous determination of the usable power (L _charging ) from the charging infrastructure, - Continuous determination of the usable battery _energy (W _batt ) of the battery, - Determination of a maximum possible running time (T _max ), which is sufficient for pre- _{air conditioning} when the usable battery _energy (W _batt ) is used by the value of the usable battery _energy (W _batt ) by e in which the power consumption for the pre-air conditioning limiting and specified power cap value (L _D ) is divided, and - determination of a switchover time (t ₁ ), from which, in addition to the energy from the charging infrastructure, an energy limited to the power cap value (L _D ) from the Battery is removed, the switchover time (t ₁ ) being determined in such a way that the remaining time (T _R ) starting from the start time (t ₀ ) up to this switchover time (t ₁ ) is less than the maximum possible running time (T _max ). Procedure according to Claim 1 , at which the wake-up time (t _s ) is determined at least as a function of the ambient temperature and / or the interior temperature of the vehicle. Method for electrical preconditioning of a passenger compartment of a vehicle, in which a battery of the vehicle is connected to a stationary charging infrastructure with a given charging power for charging and preconditioning is started at a current point in time (t _act ), the following steps being provided: Energy for pre-air conditioning from the battery and the charging infrastructure, whereby the drawn power is limited to a specified power _{cap value} (L _D ), - ongoing determination of the usable battery _energy (W _batt ) of the high-voltage battery, and - determination of a switching time (t ₃ ) from which the energy for the pre-air conditioning is taken purely from the charging infrastructure, with the switchover time (t ₃ ) being determined in such a way that at the switchover time (t ₃ ) the usable battery _energy (W _batt ) is less than a first threshold value (x ₁ Wh). Procedure according to Claim 3 , in which the preconditioning is canceled if the usable battery _energy (W _batt ) has fallen below a second threshold value (x ₂ Wh). Method according to one of the preceding claims, in which the charging power (L _charging ) of the charging infrastructure is less than the power cap value (L _D ) specified for the pre-air conditioning. Method according to one of the preceding claims, in which the power cap value (L _D ) is determined as a function of the outside temperature of the vehicle and / or the interior temperature of the vehicle.

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