DE102022004849A1 - Device and method for feeding small amounts of electrical charge into modern vehicle networks, in particular for trickle charging a battery of a vehicle - Google Patents

Abstract

The invention relates to a device (100) for trickle charging a battery (40) of a vehicle (10), at least comprising an energy source (12) which, during normal operation, is electrically coupled via a control unit (20) to an external start support point (70) of the vehicle (10), which is electrically connected to the battery (40). The control unit (20) is designed to provide current pulses (50) of the energy source (12) with a predeterminable time duration (52) at a predeterminable time interval (54) to the battery (40).The invention further relates to a method for trickle charging a battery (40) of a vehicle (10) using a device (100).

Description

The invention relates to a device and a method for feeding small amounts of electrical charge into modern vehicle networks, in particular for trickle charging a battery of a vehicle.

Vehicle batteries, especially starter batteries, are subject to natural self-discharge due to cell chemistry. If vehicles are not moved for a long time, this self-discharge can be so advanced that the vehicle can no longer be started. It is therefore common practice to charge the battery either shortly before starting again with a normal charging current or continuously with a much lower current over the time it is parked. In the latter case, this is referred to as battery maintenance charging.

The EN 10 2022 001 414 A1 describes an external start connection for an electrical on-board network of a vehicle with a separate reverse polarity protection device, wherein the reverse polarity protection device is arranged between a positive pole and a negative pole of the external start connection. The reverse polarity protection device is designed to protect electrical consumers of the electrical on-board network and/or the electrical on-board network from reverse polarity.

The EN 10 2020 112 792 A1 discloses an adapter, in particular a cable adapter, for an external start and/or external feed process into a low-voltage electrical system of a receiving vehicle. As part of the external start and/or external feed process, electrical energy can be transmitted from an energy source external to the vehicle, in particular from a vehicle battery of a donor vehicle, to the low-voltage electrical system of the receiving vehicle via an external start cable. For example, a starter of the receiving vehicle can be operated with electrical energy from the energy source external to the vehicle.

The US4661758 discloses a solar power supply and battery charging system having a solar energy source that supplies a consumption current to a load and charging current to a secondary battery when the solar energy source is exposed to sunlight. A secondary battery is connected in series with the solar energy source and is charged by the current supplied by the solar energy source. A control circuit is connected to the battery to determine the state of charge of the battery and in turn controls the operation of a variable pulse width generator. The output pulses of the pulse width generator are applied to a short circuit resistance switch connected to the terminals of the connected energy source to periodically open the short circuit switch for varying time intervals determined by the state of charge of the secondary battery.

An object of the invention is to provide an improved device for trickle charging a battery of a vehicle.

A further object is to provide an improved method for trickle charging a battery of a vehicle with such an improved device.

The above objects are solved with the features of the independent claims.

Favorable embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

While relatively low currents are required to maintain battery charge, modern vehicle architectures still respond to such continuous charging currents because significantly higher charging currents are expected during normal vehicle operation, either from the vehicle generator or from an external charger. If low charging currents are fed in anyway, especially via a jump-starting point, this generally leads to the vehicle network waking up because the vehicle responds to the normally expected high charging or starting support currents.

However, the invention here still makes it possible to use resource-saving, low charging currents in order to feed small amounts of electrical charge into modern vehicle networks, in particular for the trickle charging of a vehicle's battery.

According to one aspect of the invention, a device for trickle charging a battery of a vehicle is proposed, comprising at least one energy source which, during normal operation, is electrically coupled via a control unit to an external start support point of the vehicle which is electrically connected to the battery.

Modern vehicle networks consist of a large number of control units that communicate with each other via dedicated bus systems. Various sensors, switches and actuators are connected to these control units, which detect states or state changes, initiate or execute functions. With regard to the vehicle battery, the essential components are the battery sensor and the control unit in which the battery state is calculated. net and other control units or functions. When the vehicle is at rest, for example when parking, in the interest of maximum resource conservation, i.e. reducing the idle current of the vehicle network, the battery sensor is usually linked to the relevant control unit in such a way that if there is a noticeable and significant change in the battery parameters such as battery voltage and/or battery current, the control unit can be woken up by the sensor. This activates the monitoring functions that are essential for the system and puts the entire vehicle into a standby state for the following actions. A typical example here is the battery charging process: If a battery charger is connected to the jump-start base, a considerable charging current, typically greater than 10 amps, flows into the vehicle battery. This is detected by the sensor. The sensor then wakes up the associated control unit, which starts the battery status calculation - namely, tracking the charging current to calculate the battery's charge level.

If a small charging current is to be supplied to the battery, this must be done in such a way that the sensor does not wake up the associated control unit, because otherwise at least as much energy must be supplied as the control unit network consumes when it is in operating mode, plus the amount of energy that should actually be supplied to the battery. If this is not achieved, the charge balance is negative, i.e. the battery is actually discharged by the charging process.

In order to prevent the system from waking up, the invention selects an operating mode that is perceived by the battery sensor as a disturbance, for example due to parasitic electrical coupling. Every electronic system in the vehicle, and thus also the battery sensor, has electronic interference suppression that prevents environmental influences from irritating the vehicle system. Such environmental influences that are to be suppressed can be mechanical in nature, for example slight movements of the vehicle due to wind or the suction of passing vehicles, but also electrical in nature, for example electrical coupling from electrical systems in the immediate vicinity. These effects are known in technology as electromagnetic compatibility (EMC).

The battery sensor has such an interference suppression according to which signals are only perceived as charging or discharging currents when they exceed a certain size and/or a certain duration.

According to the invention, the low charging current to be introduced into the battery is therefore presented in the form of short pulses.

For this purpose, a control unit is connected between the charging current source, which switches the charging current source on and off cyclically. This creates current pulses that can be dimensioned in such a way that the battery sensor suppresses these current pulses as interference and does not wake up the vehicle network, i.e. does not bring it into an active operating state.

The control unit is designed to provide current pulses from the energy source with a predeterminable time duration at a predeterminable time interval to the battery.

A device for trickle charging the battery is proposed which can charge the battery with low power, for example by means of a solar module, without an active on-board network of the vehicle consuming more energy than the solar module can supply.

The energy source can advantageously be electrically coupled to the vehicle via an external starter base. The external starter base offers a clearly defined interface that enables flexible coupling of an external energy source without having to intervene in the vehicle architecture. This allows the device to be electrically connected to the vehicle in a particularly convenient way. Such an external starter base is common in many vehicles. This ensures a permanent connection to the vehicle's battery. In this way, the charging current only flows in parallel and not in series with the other systems in the vehicle's electrical system. In addition, there is no need to intervene in the battery's wiring, which is advantageous for safety reasons, especially for a retrofit system.

The device can be installed directly in a vehicle or added to a vehicle as a retrofit system. Due to the minimal intervention in the vehicle system, such a device as a retrofit system can also be installed and used permanently or only temporarily. For example, such a device can also be installed only for a longer shutdown, when parking or for waiting outside and can also be removed again when the vehicle is in continuous operation and a trickle charge is not required.

According to an advantageous embodiment of the device, the energy source can be designed as a solar module or an external battery, in particular an external starter battery, or an inductive coupled energy supply unit or a power pack. In this way, different energy sources can be connected via the jump start base, depending on availability, in order to provide a trickle charge for the vehicle's battery.

The use of a solar module as an energy source is particularly advantageous as it offers the possibility of self-sufficient battery maintenance charging based on a relatively small solar panel. Such a solar module proves to be sufficient even in unfavorable weather conditions in winter. In addition, such a solar module is particularly easy and inexpensive to implement and can be replaced if damaged.

When exposed to sunlight, the solar module generates electrical energy, which is fed into the buffer storage. The buffer storage can be designed as a capacitor, for example. As soon as the voltage of the buffer storage has reached a value that is significantly higher than the battery voltage, a current pulse can be provided to the battery.

According to an advantageous embodiment of the device, an inductively coupled energy supply unit can be installed as the energy source in such a way that energy is obtained from electrical fields, for example through conductor loops in the roadway and/or in the parking bay under the vehicle, and fed into a buffer storage from which the described current pulse can be provided.

According to an advantageous embodiment of the device, a power supply unit, for example a comparatively small plug-in power supply unit or a rechargeable battery, in particular a power bank, can also serve as an energy source to provide the energy for the current pulses.

A control unit is connected to the respective energy source, which together with the energy source forms the pulse charging module. Optionally, the control unit itself can have a buffer storage for temporarily storing electrical energy.

According to an advantageous embodiment of the device, the control unit can comprise a pulse generator or be electrically coupled to a pulse generator. The pulse generator controls the sequence and duration of the individual current pulses. The pulse generator can be connected to the control unit as a separate unit. Alternatively, however, it is also possible for the pulse generator to be integrated into the control unit.

According to an advantageous embodiment of the device, if the energy source and/or the control unit is designed with its own buffer memory, the pulse generator can be designed as a threshold switch. If the energy source is designed as a power supply unit, the power supply unit can include the pulse generator and/or the control unit. This allows the energy source and/or the control unit to be designed in a simplified and cost-effective manner.

According to an advantageous embodiment of the device, the control unit can be designed to provide the current pulses to the battery by controlling a switching element. In particular, the switching element can be designed as a semiconductor switching element, in particular as a transistor. The sequence of current pulses can be controlled via a pulse generator, which specifies the appropriate duration and time interval at which the current pulses are to be provided to the battery to the control unit. The control unit can then advantageously provide the current pulses defined in this way to the battery by controlling a suitable switching element.

In an alternative embodiment, the switching element can in particular be designed to switch a negative electrical potential.

According to an advantageous embodiment, the device and thus the pulse charging module can be electrically coupled to the external start support point via at least one fuse. In particular, the at least one fuse can be electrically coupled to a positive potential of the external start support point.

Advantageously, the pulse charging module can be electrically coupled to the vehicle via an electrical diode connected in the direction of flow. This diode ensures that the battery is not discharged backwards in the event of a fault.

The proposed device is advantageously self-sufficient in terms of energy. The control unit can be powered by the energy from the energy source.

In the case of a solar module as an energy source, this means that the moment the first ray of sunlight arrives, the buffer storage, such as a capacitor, begins to fill up and the capacitor is charged. This is regardless of whether the solar module is being used for the first time or simply when driving out of an underground car park after a long period of parking.
As soon as a voltage is reached on the capacitor, which is sufficient to operate the processor of the control unit, the control unit can start the process. Since the capacitor only discharges to a maximum of the battery voltage during recharging and this is significantly above the necessary operating voltage of the processor, the solar module remains in operation as long as the sunlight is sufficient to compensate for the self-discharge caused by the control electronics' own consumption via the solar energy that is still supplied.

Advantageously, the energy source, in particular the solar module, can be further electrically coupled to the battery via an electrical resistor in order to limit the charging current due to the voltage difference between the buffer storage and the battery when the switching element is opened.

Advantageously, the energy source can be electrically coupled to the vehicle via at least one electrical fuse. The fuse ensures that the energy source is safely disconnected from the vehicle in the event of a fault.

According to a further aspect of the invention, a method for trickle charging a battery of a vehicle with a device is proposed, wherein current pulses from an energy source with a predeterminable duration are provided at a predeterminable time interval at a jump-starting point of the vehicle, which is electrically connected to the battery, until an electrical voltage of the battery is at least equal to an electrical voltage of the energy source. The duration of the current pulse and the time interval of the current pulses are selected such that an on-board network of the vehicle remains in a passive mode.

The electrical system of a modern motor vehicle always has a low idle current, which leads to a discharge of the battery. An improved charging method for trickle charging of the battery is therefore advantageously proposed, which can charge the battery with low power, for example using a solar module, without an active electrical system of the vehicle consuming more energy than the solar module can supply.

In order to be able to charge the battery permanently with a low power to maintain the charge level, unwanted activation of the on-board network can be avoided, which would happen with a continuous charging current. It is therefore proposed that the charging current be supplied to the battery only in pulses. The current pulse can advantageously be chosen to be so short that the electronics of the on-board network are not activated and remain in a passive mode or sleep mode, with the next current pulse only occurring after a certain duration, which allows the system to remain in sleep mode. The current pulses are chosen to be so short and occur at such a large time interval that any error suppression of the on-board network suppresses these current pulses as irrelevant and the vehicle or its electrical consumers are not activated or "woken up".

The pulsation can advantageously be set depending on the particular on-board electronics used in the vehicle. The pulse length can be selected to be short enough and the charging current to be small enough that these values are acceptable within the fluctuation range of disturbances in the on-board network. This can prevent the unwanted activation of the on-board network, which would activate or wake up control units. The control units would then be active for a certain period of time and would consume power, which can be prevented according to the invention. A sufficient period of time can be waited until the next current pulse, until the on-board network has forgotten the disturbance and then, at the next current pulse, perceives the charging current as a new, tolerable disturbance that remains below an upper limit of disturbances that would otherwise lead to the on-board network being woken up.

The current pulses can be applied to the battery in a periodic sequence with a certain periodic time interval. However, this is not absolutely necessary. Optionally, the current pulses can also be applied in an irregular sequence. The time interval between the current pulses can correspond to a minimum time interval or be greater than the minimum time interval.

According to an advantageous embodiment, the method can comprise at least the steps of: determining the electrical voltages of the battery and the energy source by means of a control unit, wherein the control unit is electrically coupled to the energy source and the battery; if the electrical voltage of the battery is lower than the electrical voltage of the energy source, checking whether a control pulse of a pulse generator is present at the control unit; if the control pulse is present, switching through a switching element by the control unit, which provides the current pulse to the battery; checking whether the control pulse is switched off; if the control pulse is switched off, blocking the switching element.

In this way, the battery can be recharged with limited power without activating the vehicle electrical system. The prerequisite is that the energy source delivers a voltage that exceeds the battery voltage. The sequence of current pulses can advantageously be generated using a pulse generator. gate, which specifies the appropriate duration and time interval at which the current pulses are to be provided to the battery. The control unit can then provide the current pulses defined in this way to the battery by controlling a suitable switching element.

Advantageously, the duration of the current pulse and the time interval between the current pulses can be set manually according to predefined parameters and/or determined from a characteristic map of the vehicle and/or determined by measurements on the battery and/or the energy source. The predefined parameters can be determined in particular by the specific on-board network. The entire trickle charge system can advantageously be adjusted to different vehicle systems. The necessary values can be set manually according to parameters, read from a characteristic map for the respective vehicle or determined by testing and measuring, so that the parameters of the charging electronics for the current pulses, in particular the length, height of the current pulses and time intervals between the current pulses, can be suitably adjusted.

A solar module can advantageously be used as an energy source, whereby electrical energy generated by the solar module is temporarily stored in an electrical buffer storage unit.

The proposed method can further comprise: determining the electrical voltage of the buffer storage by means of the control unit, wherein the control unit is electrically coupled to the buffer storage and the battery; if the electrical voltage of the buffer storage is greater than the electrical voltage of the battery, checking whether it is possible to provide the current pulse; if it is possible to provide the current pulse, switching through the switching element by the control unit, which provides the current pulse to the battery; checking whether an end of the duration of the current pulse has been reached; if the end of the duration of the current pulse has been reached, blocking the switching element.

In this way, the battery can be recharged with limited power without activating the on-board network. The prerequisite is that the voltage of the buffer storage significantly exceeds the voltage of the battery. The control unit then checks whether a sufficient amount of time has passed since the last current pulse so that a new current pulse can be sent. The control unit can then provide the next current pulse to the battery by controlling the switching element. It then checks whether the duration of the current pulse has ended. When the end is reached, the switching element is blocked and the current pulse is switched off. The control unit can then go back to determining the voltage of the buffer storage. By designing the solar module appropriately in relation to the size of the buffer storage, an advantageous trickle charge can be achieved.

Further advantages emerge from the following description of the drawings. The drawings show an embodiment of the invention. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will also expediently consider the features individually and combine them into further useful combinations.

• 1 eine Systemübersicht einer Vorrichtung zur Erhaltungsladung einer Batterie eines Fahrzeugs nach einem Ausführungsbeispiel der Erfindung;
• 2 eine etwas detailliertere Systemübersicht einer Vorrichtung zur Erhaltungsladung einer Batterie eines Fahrzeugs nach dem Ausführungsbeispiel der 1;
• 3 eine Systemübersicht einer Vorrichtung zur Erhaltungsladung einer Batterie eines Fahrzeugs nach einem weiteren Ausführungsbeispiel der Erfindung;
• 4 ein Ablaufdiagramm eines Verfahrens zur Erhaltungsladung einer Batterie eines Fahrzeugs mit einer Vorrichtung nach 1 und 2;
• 5 eine zeitliche Folge von Strompulsen für eine Erhaltungsladung einer Batterie eines Fahrzeugs nach einem Ausführungsbeispiel der Erfindung.

Showing:

• 1 a system overview of a device for trickle charging a battery of a vehicle according to an embodiment of the invention;
• 2 a somewhat more detailed system overview of a device for trickle charging a battery of a vehicle according to the embodiment of the 1 ;
• 3 a system overview of a device for trickle charging a battery of a vehicle according to a further embodiment of the invention;
• 4 a flow chart of a method for trickle charging a battery of a vehicle with a device according to 1 and 2 ;
• 5 a temporal sequence of current pulses for a trickle charge of a battery of a vehicle according to an embodiment of the invention.

In the figures, identical or similar components are numbered with identical reference symbols. The figures merely show examples and are not to be understood as limiting.

1 shows a system overview of a device 100 for trickle charging a battery 40 of a vehicle 10 according to an embodiment of the invention.

The device 100 comprises an energy source 12 which, during normal operation, is electrically coupled to an external start support point 70 of the vehicle 10 via a control unit 20. The external start support point 70 is electrically connected to the battery 40 within the on-board electrical system of the vehicle 10.

The external start-up point 70 offers a clearly defined interface that allows flexible coupling an external energy source 12 without having to intervene in the vehicle architecture. This allows the device 100 to be electrically connected to the vehicle 10 in a particularly favorable manner. Such an external start support point 70 is common in many vehicles 10. This ensures a permanent connection to the battery 40 of the vehicle 10. In this way, the charging current only flows in parallel and not in series with the other systems of the vehicle's electrical system 10.

In addition, there is no need to intervene in the wiring of the battery 40, which is advantageous for safety reasons, especially for a retrofit system.

The control unit 20 is designed to provide current pulses 50 of the energy source 12 with a predeterminable time duration 52 at a predeterminable time interval 54 to the battery 40. For this purpose, the control unit 20, as in 1 shown, be electrically coupled to a pulse generator 22, which provides the temporal basis for the provision of the current pulses 50. Alternatively, the pulse generator 22 can also be integrated into the control unit 20.

The energy source 12 can, for example, be designed as a solar module.

Alternatively, the energy source 12 can also be designed as a battery, in particular as an external starter battery as part of a jump start package. It is also possible to provide an inductively coupled energy supply unit as the energy source 12. For this purpose, the vehicle 10 could be parked over a coil, for example. The energy source 12 can also be designed as a power supply unit, for example. A pulse generator 22 and/or a control unit 20 could expediently be integrated into the power supply unit.

Such a device made of 1 is in 2 in a more detailed system overview of the device 100 for trickle charging a battery of a vehicle according to a further embodiment of the invention.

The device 100 is electrically coupled to the battery 40 via the terminal 30, which represents the positive electrical potential of the battery 40, and via the terminal 31, which represents the negative electrical potential and/or the electrical vehicle ground of the battery 40. Terminal 30 and terminal 31 can be connected, for example, via the jump-start support point 70 of the vehicle 10.

In this embodiment, the control unit 20 comprises the pulse generator 22, which can simply be designed as a threshold value generator. The control unit 20 can switch the current pulses 50 to the battery 40 by controlling a switching element, for example a transistor or another suitable semiconductor switching element.

The energy source 12 is electrically coupled to the vehicle 10 via an electrical diode 30 connected in the through direction. This diode 30 ensures that the battery 40 is not discharged backwards in the event of a fault.
The energy source 12 is electrically coupled to the vehicle 10 via at least one electrical fuse 36. The fuse 36 is electrically coupled to the positive potential of the jump-start support point 70. The fuse 36 ensures that the energy source 12 is safely separated from the vehicle 10 in the event of a fault.

Advantageously, the proposed device 100 has an energy self-sufficiency. The control unit 20 is fed by the energy of the energy source 12

In an alternative embodiment of the device in 3 The energy source 12 can, for example, be designed as a solar module 14 with an electrical buffer storage 16, which is designed to temporarily store electrical energy generated by the solar module 14.

Here, 3 a system overview of an alternative device 100 for trickle charging a battery of a vehicle according to a further embodiment of the invention.

The energy source 12 is designed as a solar module 14 with an electrical buffer storage 16, wherein the buffer storage 16 serves to temporarily store electrical energy generated in the solar module 14. The buffer storage 16 can be designed as a capacitor, for example.

The device 100 is electrically coupled to the battery 40 via the terminal 30, which represents the positive electrical potential of the battery 40, and via the terminal 31, which represents the negative electrical potential and/or the electrical vehicle ground of the battery 40. Terminal 30 and terminal 31 can be connected, for example, via the jump-start support point 70 of the vehicle 10.

The control unit 20 can supply the current pulses 50 to the battery 40 by controlling a switching element 24, for example a transistor or another suitable semiconductor switching element. ments, via the negative electrical potential. For this purpose, the switching element 24 is electrically coupled to a negative potential of the external start support point 70, in particular a vehicle ground of the external start support point 70.

In this embodiment, the control unit 20 comprises the pulse generator 22, which can simply be designed as a threshold value generator.

The solar module 14 is electrically coupled to the buffer storage 16 via an electrical diode 30 connected in the direction of flow. The diode 30 prevents the buffer storage 16 from being reversed when the solar radiation decreases.

The energy source 12 is electrically coupled to the vehicle 10 via an electrical diode 32 connected in the through direction. This diode 32 ensures that in the event of a fault the battery 40 does not reverse charge the buffer storage 16.

The energy source 12 is electrically coupled to the battery 40 via an electrical resistor 34 in order to limit the charging current due to the voltage difference between the buffer storage 16 and the battery 40 when the switching element 24 is opened.

The energy source 12 is electrically coupled to the vehicle 10 via at least one electrical fuse 36. The fuse 36 is electrically coupled to the positive potential of the jump-start support point 70. The fuse 36 ensures that the energy source 12 is safely separated from the vehicle 10 in the event of a fault.

When exposed to sunlight, the solar module 14 generates electrical energy, which is fed into the buffer storage 16. The buffer storage 16 can be designed as a capacitor, for example. As soon as the voltage of the buffer storage 16 has reached a value that is significantly higher than the battery voltage, a current pulse 50 can be provided to the battery 40.

The proposed device 100 advantageously has a self-supplying energy supply. The control unit 20 as a solar controller is fed by the energy of the solar module 14. This means that the moment the first ray of sunlight arrives, the buffer storage 16, for example a capacitor, begins to fill up and the capacitor is therefore charged. This is independent of whether the solar module 14 is being put into operation for the first time or just driving out of an underground car park after a long period of parking.

As soon as a voltage is reached on the capacitor that is sufficient to operate the processor of the control unit 20, the control unit 20 starts the process. Since the capacitor only discharges to a maximum of the voltage of the battery 40 during recharging and this is significantly above the necessary operating voltage of the processor, the solar module 14 remains in operation as long as the solar radiation is sufficient to compensate for the self-discharge caused by the self-consumption of the control unit 20 via the solar energy that is still supplied.

In 4 is a flow chart of a method for trickle charging a battery 40 of a vehicle 10 with the device 100 according to 1 shown.

According to the method, current pulses 50 of an energy source 12 with a predeterminable time duration 52 are provided to the battery 40 at a predeterminable time interval 54 until an electrical voltage of the battery 40 is at least equal to an electrical voltage of the energy source 12. The time duration 52 of the current pulse 50 and the time interval 54 of the current pulses 50 are selected such that an on-board network of the vehicle 10 remains in a passive mode.

It has been empirically determined that current pulses of, for example, 4 seconds in length and at least 15 seconds in pause are ignored by the on-board electrical system of a vehicle 10.

In 5 1 shows an example of such a temporal sequence of current pulses 50. The current 61 varies as a function of time 60 between an off state 64 and an on state 62. The current pulses 50 have a temporal duration 52 and are provided with a minimum temporal interval 54. A larger temporal interval 54 can optionally be selected.

The method comprises at least the 4 The process is started in step S 100. Then, in step S 102, the electrical voltages of the battery 40 and the energy source 12 are determined by means of the control unit 20.

In the next step S104, it is checked whether the electrical voltage of the battery 40 is lower than the electrical voltage of the energy source 12. If this is not the case, the determination of the electrical voltages is repeated in step S102.

This loop is repeated until the voltage of the battery 40 is lower than the voltage of the energy source 12.

Then, in step S106, it is checked whether a control pulse of a pulse generator 22, which is generated in step S114, is present at the control unit 20. If this is not the case, the determination of the electrical voltages is repeated in step S102.

If the control pulse is present, the control unit 20 in step S108 switches on a switching element 24, for example a switch or a transistor, which provides the current pulse 50 to the battery 40.

Then, in step S110, it is checked whether the control pulse is switched off again. If this is not the case, the system returns to step S108. This is repeated until the control pulse is switched off.

If the control pulse is switched off, the switching element 24 is blocked in step S112, whereby the current pulse 50 is terminated. The loop is then restarted with step S102.

The duration 52 of the current pulse 50 and the time interval 54 of the current pulses 50 can be set manually according to predeterminable parameters. Alternatively or additionally, the values can be determined from a characteristic map of the vehicle 10. It is also possible for the values to be determined by measurements on the battery 40 and/or the energy source 12.

In this way, the battery 40 can be recharged with limited power without activating the vehicle electrical system. The prerequisite is that the energy source 12 supplies a voltage that exceeds the voltage of the battery 40. The sequence of current pulses 50 can advantageously be controlled via a pulse generator 22, which specifies the appropriate duration and time interval at which the current pulses 50 are to be provided to the battery 40 to the control unit 20. The control unit 20 can then provide the current pulses 50 defined in this way to the battery 40 by controlling a suitable switching element 24.

A sequence of a method for trickle charging a battery 40 of a vehicle 10 with the device 100 according to 3 , i.e. with a solar module 14 as energy source 12 could proceed as follows.

After initialization, i.e. reaching the processor operating voltage in step S200, the control unit 20 starts measuring the voltage of the buffer memory 16 in step S202, which is proportional to the charge state of the buffer memory 16, for example a capacitor, and thus a measure of the memory content of the buffer memory 16.

If this charge level is high enough, i.e. the capacitor voltage is, for example, 2 V above the nominal battery voltage, which is checked in step S204, the algorithm checks in step S206 whether a current pulse 50 was not already sent shortly beforehand. The necessary charging pause, the minimum time interval 54 between the current pulses 50, is therefore checked so that the on-board network of the vehicle 10 is not woken up.

If the charging pause has already elapsed, for example when a so-called charge enable flag was set, the switching element 24 switches through in step S208 and the buffer memory 16 discharges into the battery 40. A corresponding current pulse 50 is provided to the battery 40.

During this process, a check is carried out in step S210 to determine whether the end of the charging pulse duration, i.e. an end of the duration 52 of the current pulse 50, has already been reached. If not, the switching element 24 remains open.

When the end of the charging pulse duration is reached, the switching element 24 is switched off in step S212 and the algorithm returns to the area of measuring the voltage of the buffer memory 16 in step S202.

In real use, the length of the charging break can depend on the amount of sunlight. On days with little sun, the solar module 14 supplies little energy, which means that the buffer storage 16 charges very slowly, depending on the ratio of the size of the solar module 14 to the capacity of the buffer storage 16, for example a capacitor. Charging breaks of up to several minutes or even an entire night are therefore also conceivable. On sunny days, the capacitor 16 can be charged in significantly less than 15 seconds. In this case, the control unit 20 must prevent the switching element 24 from switching through prematurely.

List of reference symbols

10

vehicle

12

Energy source

14

Solar module

16

Buffer storage

20

Control unit

22

Pulse generator

24

Switching element

30

diode

32

diode

34

Resistance

36

Backup

40

battery

50

Current pulse

52

duration

54

temporal distance

60

Time

61

Electricity

62

A

64

Out of

70

External launch base

100

contraption

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 102022001414 A1 [0003]
• DE 102020112792 A1 [0004]
• US 4661758 [0005]

Claims (9)

Device (100) for trickle charging a battery (40) of a vehicle (10), comprising at least an energy source (12) which, in normal operation, is electrically coupled via a control unit (20) to an external start support point (70) of the vehicle (10), which is electrically connected to the battery (40), wherein the control unit (20) is designed to provide current pulses (50) of the energy source (12) with a predeterminable time duration (52) at a predeterminable time interval (54) to the battery (40). Device according to Claim 1 , wherein the energy source (12) is designed as one of a solar module (14), or inductively coupled energy supply unit, or battery, in particular an external starter battery, or power supply unit. Device according to 2, wherein the solar module (14) or the inductively coupled energy supply unit has an electrical buffer storage (16) which is designed for the intermediate storage of electrical energy from the solar module or the inductively coupled energy supply unit. Device according to one of the preceding claims, wherein the control unit (20) comprises a pulse generator (22) or is electrically coupled to a pulse generator (22). Device according to Claim 4 , wherein, if the energy source (12) is designed as a solar module (14) with a buffer storage (16), the pulse generator (22) is designed as a threshold switch, if the energy source (12) is designed as a power supply unit, the power supply unit comprises the pulse generator (22) and/or the control unit (20). Device according to one of the preceding claims, wherein the control unit (20) is designed to provide the current pulses (50) to the battery (40) by controlling a switching element, in particular wherein the switching element is designed as a semiconductor switching element, in particular as a transistor. Device according to one of the preceding claims, wherein the energy source (12) is electrically coupled to the external start support point (70) via at least one fuse (36), in particular wherein the at least one fuse (36) is electrically coupled to a positive potential of the external start support point (70). Method for trickle charging a battery (40) of a vehicle (10) with a device (100) according to one of the preceding claims, wherein current pulses (50) of an energy source (12) with a predeterminable time duration (52) are provided at a predeterminable time interval (54) at an external start support point (70) of the vehicle (10), which is electrically connected to the battery (40), until an electrical voltage of the battery (40) is at least equal to an electrical voltage of the energy source (12), wherein the time duration (52) of the current pulse (50) and the time interval (54) of the current pulses (50) are selected such that an on-board network of the vehicle (10) remains in a passive mode. Procedure according to Claim 8 , comprising at least the steps of - determining the electrical voltages of the battery (40) and the energy source (12) by means of a control unit (20), the control unit (20) being electrically coupled to the energy source (12) and the battery (40); - if the electrical voltage of the battery (40) is lower than the electrical voltage of the energy source (12), checking whether a control pulse of a pulse generator (22) is present at the control unit (20); - if the control pulse is present, switching through a switching element by the control unit (20), which provides the current pulse (50) to the battery (40); - checking whether the control pulse is switched off; - if the control pulse is switched off, blocking the switching element.

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