Device for operating electrical energy storage devices, system for charging electrical energy storage devices and locking system

Abstract

A device (1) for operating electrical energy storage devices (C1, C2) is described. Furthermore, a system (2) for charging electrical energy storage devices (C1; C2) is described, wherein the system (2) may include the device (1). Finally, a locking system (10) for a vehicle (12) with such a system (2) is described.

Description

Technical field

[0001] A device for operating electrical energy storage devices is described. Furthermore, a system for charging electrical energy storage devices is described, wherein the system may include the device. Finally, a locking system with such a system for charging electrical energy storage devices is described. State of the art

[0002] Vehicles, such as cars, have various systems and devices that require a power supply. Some of these systems and devices are powered directly by the vehicle's electrical system. However, some of these systems and devices are safety-critical. These safety-critical systems and devices require a backup power supply in addition to the direct power supply from the vehicle's electrical system. For example, vehicles often have additional energy storage devices, such as supercapacitors, to supply these safety-critical systems and devices with power even if the vehicle's electrical system fails. These energy storage devices, such as supercapacitors, must be charged before they can be used.To achieve a specific voltage with these energy storage devices, several supercapacitors are connected in series, for example, to reach a specific voltage for a particular system or vehicle component. When charging these energy storage devices and supercapacitors, the goal is to charge them with the same voltage. In conventional energy storage devices and supercapacitors, this is achieved via dissipative elements, such as electrical resistors. If an energy storage device, in this case a supercapacitor, is charged beyond its intended capacity, the excess electrical energy is dissipated from the supercapacitor via, for example, a parallel electrical resistor. This allows the series-connected supercapacitors to be balanced. The dissipative energy lost during this balancing process is considered energy loss. Description of the invention

[0003] A first aspect concerns a device for operating electrical energy storage devices. The device may include or be an electrical circuit. Operating the energy storage devices may involve charging and / or discharging them. The electrical energy storage devices may consist of two or more devices. They may include at least one type of supercapacitor, capacitor, or accumulator. The electrical energy storage devices may, for example, be connected in series. The electrical energy storage devices may be configured, for example, to absorb power peaks in vehicles by providing additional energy to a device or system within the vehicle, in addition to energy from the vehicle's electrical system.Alternatively or additionally, these electrical energy storage devices can be used as backup and alternatively or additionally as short-term buffers of electrical energy.

[0004] The device includes a measuring device configured to measure a voltage across the energy storage devices. The measuring device can be configured to measure at least one voltage across at least one energy storage device. The measuring device can also be configured to measure a voltage across all energy storage devices. For example, the measuring device can be configured to measure at least one or more potentials across the device and, alternatively or additionally, across the energy storage devices, such as at their terminals. For instance, the measuring device can be configured to measure at least one potential at at least one terminal of an energy storage device configured as a supercapacitor.

[0005] The device further comprises a charging device configured to change the state of charge of the energy storage devices. The charging device can be configured to charge at least one energy storage device. The charging device can be configured to discharge at least one energy storage device. The charging device can be configured to charge and / or discharge all energy storage devices. By charging and, alternatively or additionally, discharging, the state of charge of at least one energy storage device can be changed. The measuring device and the charging device can include electrical elements of an electrical circuit. The measuring device and the charging device can be configured separately from each other. Alternatively, the measuring device and the charging device can share at least one electrical component, such as a resistor.

[0006] Both the measuring device and the charging device are connected via the same electrical interface. This electrical interface can be a pin, for example, a control pin of a control unit. Both the measuring device and the charging device can be accessed by the control unit via this interface. The control unit can be configured to access both the measuring device and the charging device via the interface, such as a pin like a control pin. The measuring device and the control unit can be accessed by the control unit via exactly one interface, such as exactly one pin.

[0007] For example, the control unit can be configured to use and / or control the measuring device for measuring the voltage at the energy storage devices via the electrical interface. Furthermore, the control unit can be configured to use and / or control the charging device for changing the state of charge of the energy storage devices via the electrical interface. The control unit can, for example, be part of a vehicle, and the device itself can also be part of the vehicle. The control unit can, for example, include an analog-to-digital converter. The measuring device for measuring the voltage at the energy storage devices can be controlled and used via this analog-to-digital converter. Furthermore, the control unit can have an input / output interface, which it can use to control the charging device.Both the analog-to-digital converter and the input / output can be electrically connected to the device, and thus to the measuring device and the charging device, via the electrical interface, for example, precisely the same electrical interface. The control unit can be configured, for example, to use either the analog-to-digital converter or the input / output.

[0008] The control unit can be located externally to the device or, alternatively, be part of the device. The energy storage devices can be located externally to the device or, alternatively, be part of the device. The interface can be part of the device and / or part of the control unit.

[0009] Such a device can be used to operate electrical energy storage devices, for example, charging and, alternatively or additionally, discharging them. For instance, supercapacitors used as electrical energy storage devices in a vehicle can be charged. Specifically, at least two supercapacitors connected in series can be charged in such a way that a uniform charge distribution, such as a 50:50 charge distribution, between the two supercapacitors can be achieved using the device. First, the voltage across the energy storage devices can be measured. If the voltages are not identical, the charging device can be used to change the state of charge of at least one of the two energy storage devices, or, in this case, both.When changing the state of charge, electrical energy can be transferred to the first energy storage device and, alternatively or additionally, to the second, and / or from the first and, alternatively or additionally, to the second. The device can transfer energy from one energy storage device to another, thus avoiding the need to achieve an equal charge distribution between the energy storage devices through dissipative processes. Instead, the state of charge of the energy storage devices can be increased or decreased. For example, a target maximum voltage of 2.7 V for supercapacitors can be achieved and, for instance, not exceeded. This ensures component protection for the energy storage devices, in this case, the supercapacitors.Furthermore, the device can achieve an increase in performance or power with regard to the energy storage capacity of the electrical energy storage devices, since all energy storage devices can be optimally fully charged, for example up to their maximum charging capacity.

[0010] According to another embodiment, the measuring device can have a first resistor. Here, as in the following, the term "first resistor" is used solely to distinguish it from other resistors. The presence of a first resistor does not necessarily imply, for example, that a second resistor must be present in the device. Furthermore, the presence of a second resistor does not, for example, imply that a first or third resistor must be present. The nomenclature serves only for differentiation. This applies to this embodiment as well as to other embodiments, including those with regard to other aspects.

[0011] A first potential between a first energy storage device and a second energy storage device can be measured, for example, via the first resistance at the interface. If the device has exactly two energy storage devices, the first and the second, this first potential should correspond to half the supply voltage of the series-connected energy storage devices. The supply voltage is, for example, the voltage applied to a terminal of one of the series-connected energy storage devices that is located at the end of the series and is not connected to ground. The supply voltage could, for example, correspond to the supply voltage of the control unit.

[0012] If the first potential measured by the measuring device does not correspond to half the supply voltage, the charging device can be controlled to change the state of charge so that, for example iteratively, the first potential reaches this state, i.e., so that the first potential corresponds to half the value of the supply voltage. Thus, the first potential can be measured simply, and the voltage at the energy storage devices can then be measured.

[0013] According to another embodiment, a second potential can be connected to the first potential via the first energy storage device. The second potential can be equal to the supply voltage of the control unit. The first potential can be connected to a third potential via the second energy storage device. The third potential can be ground. If the device has more than two energy storage devices, further potentials can be present between the series-connected energy storage devices, for example, supercapacitors. The aim is then to achieve an equal voltage distribution across the energy storage devices.

[0014] According to another embodiment, the charging device can include a second resistor, a third resistor, and a first transistor. Optionally, the charging device can also include the first resistor. The second potential can be connected to a collector of the first transistor via the second resistor. A base of the first transistor can be controlled by the control device via the interface through the third resistor. An emitter of the first transistor can be connected to the first potential. The emitter can be connected to the interface via the first resistor.

[0015] By switching the first transistor via the interface, the control unit allows current to flow from the collector to the emitter. Current flow is defined here with respect to conventional current direction. This shifts the first potential upwards, allowing the second energy storage device to be charged. This can be done for a specific period of time; for example, the first transistor can be switched on for a certain duration. This can occur, for instance, as long as the first potential is less than half the potential of the second.

[0016] This consideration applies to two energy storage devices. If the device has more than two energy storage devices, the respective potential between the two energy storage devices corresponds to a specific fraction of the supply voltage as the second potential.

[0017] According to a further embodiment, the charging device can include a fourth resistor, a fifth resistor, and a second transistor. The charging device can also include the first resistor. Additionally, the charging device can include the second and third resistors and the first transistor described above. The first potential can be connected to an emitter of the second transistor. The emitter can be connected to the interface via the first resistor. A base of the second transistor can be controlled by the control device via the interface through the fourth resistor. A collector of the second transistor can be connected to the third potential via the fifth resistor.

[0018] For example, the measuring device might have determined that, with two energy storage devices, the potential of the first is greater than half the potential of the second. This could mean that the second energy storage device is more charged than the first. Then, for a specific period of time, and for example, as long as the potential of the first remains greater than half the potential of the second, the second transistor can be switched on, allowing current to flow from the emitter to the collector. Here, too, the conventional current direction is considered. This can shift the potential of the first transistor downwards. This allows the first energy storage device to be charged, and the second energy storage device can, for example, be discharged.

[0019] According to another embodiment, the first transistor can be an NPN transistor and the second transistor can be a PNP transistor. The device can be configured in a push-pull arrangement. For example, either the first or the second transistor can be switched via the interface. A second interface is not necessary.

[0020] A second aspect concerns a system for charging electrical energy storage devices. These devices can be supercapacitors, as previously described. The system may or may not include these devices. The system may include a control unit, such as the one described earlier, which can be configured to control either fast or slow charging of the energy storage devices. Fast charging, also known as high-current charging, can be performed with a high current of, for example, 0.5 A to 2.5 A. Slow charging, also known as slow-current charging, can be performed with a current of a few milliamperes. Precise charging can also be implemented using slow charging.

[0021] With such a system, energy storage devices, such as two supercapacitors connected in series, can be charged quickly and precisely. The system can provide a combination of fast and slow charging, or high-power and super-slow charging. The control unit can include or implement power management. Slow charging, combined with precise charging, can result in very low self-discharge, for example, of supercapacitors. This can reduce energy loss, or leakage, from energy storage devices like supercapacitors by orders of magnitude compared to a scenario where the supercapacitors are charged only at high speed, rather than at low speed.

[0022] According to a further embodiment, the system may also include a device for operating the electrical energy storage devices according to an embodiment of the first aspect for the slow charging of the energy storage devices. The device may be configured to perform the slow charging of the energy storage devices. Further features, embodiments, and advantages of the second aspect can be derived from features, embodiments, and advantages of the first aspect. Furthermore, features, embodiments, and advantages of the second aspect represent features, embodiments, and advantages of the first aspect.

[0023] According to another embodiment, the system further comprises a switch, a first diode, and a second diode. The switch can be a bypass, a transistor, a resistor, or a switch-mode regulator. The first diode can be a polarity protector. A third potential can be connected to the switch via the first diode. This third potential can correspond to 12 V. The third potential can correspond to the vehicle electrical system voltage of a vehicle, which the system may incorporate. The switch can be connected to the second potential via the second diode. The switch can be connected, or connectable, to series-connected energy storage devices via the second diode.

[0024] The control unit can be configured to control the switch for fast charging the energy storage devices. Closing the switch allows the energy storage devices to be charged quickly, in this case with the vehicle's electrical system voltage of 12 V. The value of the second potential can then be set to 12 V, enabling fast charging of the energy storage devices. This allows the state of charge of the energy storage devices to be changed quickly; for example, the two supercapacitors, which serve as energy storage devices for the system and, for instance, the device itself, can be fast charged.

[0025] According to another embodiment, the system can further include a sixth resistor, a seventh resistor, and a third diode. Optionally, the system can also include an additional switch. The sixth resistor can be a voltage regulator to regulate the on-board voltage from 12 V to, for example, 5 V. The seventh resistor can be a current limiter, for example, in the range of 30 Ω to 200 Ω. The seventh resistor can be used to regulate and / or limit the charging current to the order of milliamperes.

[0026] The first diode can be connected to the third diode via the sixth resistor. The third diode can be connected to the second potential via the seventh resistor. The third diode can be connected to the seventh resistor via the additional switch. The third diode can be connected, or connectable, to series-connected energy storage devices, such as supercapacitors, via the seventh resistor, optionally via the switch between the third diode and the seventh resistor. During slow charging, the second potential can be 5 V.

[0027] A third aspect concerns a locking system for a vehicle. The vehicle can be a passenger car or a truck. The locking system can be used for a vehicle door or a trunk lid, for example, to lock the vehicle door or trunk lid.

[0028] The locking system can be a system according to an embodiment of the second aspect. Furthermore, the locking system can have at least two electrical energy storage devices, such as at least two supercapacitors. The locking system can also have more than two energy storage devices. Furthermore, the locking system can have a voltage source for supplying the energy storage devices with electrical energy. For example, the voltage source can be part of an on-board electrical system and, for example, be a vehicle battery. Furthermore, the locking system can have a locking device. The locking device can, for example, have an actuator and a bolt movable by the actuator for locking. The voltage source can be configured to supply the locking device with electrical energy, for example, as a primary power supply.

[0029] The energy storage devices can be configured to supply the locking mechanism with electrical energy, for example, as a secondary power supply. For instance, the actuator of the locking mechanism can be powered by the energy from the storage devices. The energy storage devices can also be used as an energy backup and, for example, as a safety device. This allows the locking mechanism to be used even when the primary power source, such as the vehicle's electrical system, is unavailable, for example, due to a fault. This provides a particularly safe and reliable locking system with energy storage. Further details, features, and advantages of the third aspect can be found in the descriptions of the first and second aspects.Furthermore, the descriptions, features and advantages of the third aspect represent the descriptions, features and advantages of the first and second aspects. Brief description of the characters Fig. Figure 1 schematically shows a device for operating electrical energy storage devices. Fig. Figure 2 schematically shows a system for charging electrical energy storage devices with a device made of Fig. 1. Fig. Figure 3 schematically shows a vehicle with a locking system and the [unclear text]. Fig. 2 systems shown. Detailed description of embodiments

[0030] Fig. Figure 1 schematically shows a device 1 for operating electrical energy storage devices C1, C2. Fig. Figure 1 shows a circuit diagram. The electrical energy storage devices C1 and C2 can be, for example, supercapacitors or accumulators. A first energy storage device C1 is shown as the first supercapacitor, and a second energy storage device C2 as the second supercapacitor. The two energy storage devices C1 and C2 are not part of the device 1, but are electrically connected to it. The two energy storage devices C1 and C2 are connected in series.

[0031] Furthermore, in Fig. Figure 1 shows a control unit µC. This is not part of the device 1, but is electrically connected to it. The control unit µC has an analog-to-digital converter (ADC) and an input-to-output (IO). Both are internally connected to each other within the control unit µC. Both are connected to the device 1 via exactly one electrical interface P. In one embodiment, the electrical interface P is a pin, such as a control pin, and part of the control unit µC. In an alternative embodiment, the electrical interface P is part of the device 1. In yet another alternative embodiment, the electrical interface P is neither part of the device 1 nor part of the control unit µC.

[0032] Device 1 includes a measuring device configured to measure the voltage across energy storage devices C1 and C2. The measuring device includes a first resistor R1. A first potential V1 between the first energy storage device C1 and the second energy storage device C2 can be measured at interface P via the first resistor R1. The control unit µC is configured to measure this first potential V1 via interface P and the first resistor R1 using the analog-to-digital converter AD.

[0033] Furthermore, a second potential V2 is connected to the first potential V1 via the first energy storage device C1. The second potential V2 corresponds to the supply voltage of the control unit µC. In this embodiment, this corresponds to 5 V. The first potential V1 is connected to the third potential G via the second energy storage device C2. The third potential G corresponds to ground.

[0034] Device 1 further comprises a charging device configured to change the state of charge of at least one of the energy storage devices C1 and C2. In one embodiment, the charging device is configured to change the state of charge of all energy storage devices C1 and C2. In alternative embodiments, Device 1 comprises more than two energy storage devices. In these cases, the charging device can also be configured to change the state of charge of at least one energy storage device, as well as all energy storage devices. The charging device comprises a second resistor R2, a third resistor R3, and a first transistor T1. The first transistor T1 is an NPN transistor. The charging device also comprises a first resistor R1, which it shares with the measuring device. The charging device further comprises a fourth resistor R4, a fifth resistor R5, and a second transistor T2. The second transistor T2 is a PNP transistor.

[0035] The second potential V2 is connected to a collector of the first transistor T1 via the second resistor R2. A base of the first transistor T1 can be controlled by the control unit (µC) via interface P through the third resistor R3. The base of the first transistor T1 is connected, or can be connected, to interface P via the third resistor R3. An emitter of the first transistor T1 is connected to the first potential V1. Furthermore, the emitter of the first transistor T1 is connected, or can be connected, to interface P via the first resistor R1.

[0036] The first potential V1 is connected to an emitter of the second transistor T2. The emitter of the second transistor T2 is connected, or connectable, to interface P via the first resistor R1. A base of the second transistor T2 is controllable by the control unit µC via interface P through the fourth resistor R4. The base of the second transistor T2 is connected, or connectable, to interface P via the fourth resistor R4. A collector of the second transistor T2 is connected, or connectable, to the third potential G via the fifth resistor R5.

[0037] Both the measuring device and the charging device are connected via the same electrical interface P. There is only one interface between the device 1 and the control unit µC. Both the measuring device and the charging device can be used and controlled by the control unit µC via this interface P.

[0038] The first step involves measuring the voltage across energy storage devices C1 and C2. The microcontroller (µC) uses its analog-to-digital converter (ADC) for this measurement. The first potential, V1, is measured via interface P and the first resistor, R1. If the measurement shows that the first potential, V1, is exactly half the value of the second potential, V2, then the two energy storage devices, C1 and C2, are equally charged, and their charge levels do not need to be changed.

[0039] However, if the first potential V1, measured by the control unit µC, does not correspond to half of the second potential V2, the charging device is used to change the state of charge of the energy storage devices C1 and C2. In this case, the analog-to-digital converter AD is no longer controlled by the control unit µC for measurement; instead, the input-output IO of the control unit µC is used to control the charging device via interface P.

[0040] For example, if it is measured that the first potential V1 is more than half the value of the second potential, this means that the second energy storage device C2 is more highly charged than the first energy storage device C1. The goal is then to adjust the charge levels so that both energy storage devices C1 and C2 are approximately equally charged. This is achieved by reducing the first potential V1. This is done by switching the second transistor T2. The second transistor T2, a PNP transistor, is switched by reducing the potential at interface P via the input / output IO, for example, to 0 V. However, the emitter is at the positive voltage of the first potential V1. This makes the base-emitter voltage of the second transistor T2 negative, since the base is at 0 V. Simultaneously, the base-emitter voltage of the first transistor T1 becomes positive.The first transistor T1 is not switched on. Thus, the first potential V1 is pushed downwards and the first energy storage device C1 is charged, while the second energy storage device C2 is discharged.

[0041] Alternatively, the measuring device determines that the second energy storage device C2 is less charged than the first energy storage device C1. For example, it is determined that the first potential V1 is less than half the second potential V2. The first potential V1 must then be shifted upwards. This is achieved by switching on the first transistor T1. This, in turn, is accomplished by applying a high potential, for example 5 V, to interface P via the input / output IO of the control unit µC and interface P. This makes the base-emitter voltage of the NPN transistor, in this case the first transistor T1, positive. Simultaneously, the base-emitter voltage of the second transistor T2, in this case the PNP transistor, is negative, and therefore the second transistor T2 is not switched on. Thus, current flows from the second potential V2 to the first potential V1, and the first potential V1 is shifted upwards.This discharges the first energy storage device C1 and charges the second energy storage device C2.

[0042] Fig. Figure 2 shows a system 2 for charging electrical energy storage devices C1, C2. Fig. Figure 2 shows a circuit diagram. Fig. 2 are the ones from Fig. Energy storage devices C1 and C2 are shown in Figure 1. In one embodiment, these two energy storage devices C1 and C2 are part of System 2; in an alternative embodiment, they are not part of System 2 and are separate from System 2. System 2 includes the device 1. Fig. 1. Furthermore, system 2 also shows the control unit µC. Fig. 1. The control unit µC is connected to the device 1, as described with regard to Fig. 1, also shown in system 2 and in Fig. 2 is connected via interface P. There are no other interfaces between device 1 and the control unit µC.

[0043] System 2 further comprises a switch 8, a first diode D1, and a second diode D2. A third potential V3 is connected to switch 8 via the first diode D1. The third potential V3 corresponds to the vehicle electrical system voltage, in this case 12 V. Switch 8 is connected to the second potential V2 via the second diode D2. Switch 8 is connected via the second diode D2 to the series-connected energy storage devices C1 and C2, and then to the third potential G, in this case ground. The control unit µC is configured to control switch 8. For this purpose, the control unit µC is communicatively connected to switch 8.

[0044] System 2 also includes a sixth resistor R6, a seventh resistor R7, another switch S, and a third diode D3. The first diode D1 is connected to the third diode D3 via the sixth resistor R6. The third diode D3 is connected to the seventh resistor R7 via the second switch S. The third diode D3 is further connected to the second potential V2 via the seventh resistor R7. The sixth resistor R6 is thus also connected to the series-connected energy storage devices C1 and C2 via resistor R7.

[0045] For improved clarity, a fourth potential V4 is shown. The sixth resistor R6 and the third diode D3 are directly electrically connected. Instead of the direct electrical connection, the fourth potential is shown here as a representative example.

[0046] Furthermore, a fifth potential V5 is shown between the third diode D3 and the seventh resistor R7 and the further switch S.

[0047] Furthermore, application 4 is shown, which is connected via the first diode D1 to the third potential V3, here the vehicle electrical system voltage. Application 4 is an application that can be operated using the vehicle electrical system voltage.

[0048] System 2 is configured to control either fast charging or slow charging of energy storage devices C1 and C2. Both energy storage devices C1 and C2 are initially discharged. The control unit (µC) then activates and closes switch 8. This enables fast charging of the two energy storage devices C1 and C2 using the vehicle's electrical system voltage. The second potential, V2, is then 12 V.

[0049] Once a certain charge level of the two energy storage devices C1 and C2 has been reached, measurable by the measuring device of device 1 and by the control unit µC, switch 8 is opened. This is controlled by the control unit µC. This terminates the fast charging process.

[0050] Device 1 is then used for the slow charging of energy storage devices C1 and C2. The vehicle electrical system voltage, shown here via the third potential V3, is reduced from 12 V to 5 V via the sixth resistor R6. The seventh resistor R7 is a current limiter and restricts the high current supplied by the vehicle electrical system voltage to low currents, here a few milliamperes. This allows the control unit µC to control the slow charging of the two energy storage devices C1 and C2 using Device 1. During slow charging, the second potential V2 corresponds to 5 V.

[0051] Fig. Figure 3 schematically shows a vehicle 12 with a locking system 10. The locking system 10 is part of a door of the vehicle 12 (not shown) and is designed to lock this door. The locking system 10 features the system 2, shown from Fig. 2. Furthermore, the locking system 10 already features the two in the Fig. 1 and Fig. The system 2 includes two energy storage devices, C1 and C2. These two energy storage devices, C1 and C2, are supercapacitors. Furthermore, the locking system 10 has a voltage source 14 for supplying the energy storage devices C1 and C2 with electrical energy. The voltage source 14 supplies the system 2 at the third potential V3, as shown in the figure. Fig. 2, with a vehicle electrical system voltage of 12 V.

[0052] Furthermore, the locking system 10 includes a locking device 16. This device is configured to lock the door, for example with a bolt and an actuator that can move this bolt to lock the door. The voltage source 14 is configured as the primary power supply for the locking device 16.

[0053] The energy storage devices C1 and C2 are also configured to supply the locking device 16 with electrical energy, namely as a secondary power supply. Under normal circumstances, the voltage source 14 is configured to supply the locking device 16 with electrical energy. However, if a fault occurs in the voltage source 14 and, for example, the vehicle's electrical system voltage is not directly available to supply the locking device 16, the energy storage devices C1 and C2 can be used to supply the locking device 16 with electrical energy. This provides a particularly secure locking system 10, which is also fail-safe. Reference sign 1 Device 2 System 4 Application 8 switches 10 locking system 12 vehicles 14 Voltage source 16 Locking device AD Analog-to-Digital Converter C1, C2 Energy storage D1, D2, D3 diodes IO Input-Output µC control unit P interface R1 - R7 Resistor S further switch T1, T2 Transistor V1 - V5, G Potential

Claims

[1] Device (1) for operating electrical energy storage devices (C1, C2), comprising: - a measuring device which is set up to measure a voltage at the energy storage devices (C1, C2); - a charging device which is designed to change the state of charge of the energy storage devices (C1, C2); - wherein both the measuring device and the charging device are connected via the same electrical interface (P) and can be used by a control device (µC) via this interface (P). [2] Device (1) according to claim 1, wherein the measuring device has a first resistance (R1), wherein a first potential (V1) between a first energy storage device (C1) and a second energy storage device (C2) can be measured via the first resistance (R1) at the interface (P). [3] Device (1) according to claim 2, wherein a second potential (V2) is connected to the first potential (V1) via the first energy storage (C1), wherein the first potential (V1) is connected to a third potential (G) via the second energy storage (C2). [4] Device (1) according to claim 3, wherein the charging device has a second resistor (R2), a third resistor (R3) and a first transistor (T1), wherein the second potential (V2) is connected via the second resistor (R2) to a collector of the first transistor (T1), wherein a base of the first transistor (T1) can be controlled via the third resistor (R3) by the control device (µC) via the interface (P) and wherein an emitter of the first transistor (T1) is connected to the first potential (V1). [5] Device (1) according to claim 3 or 4, wherein the charging device has a fourth resistor (R4), a fifth resistor (R5) and a second transistor (T2), wherein the first potential (V1) is connected to an emitter of the second transistor (T2), wherein a base of the second transistor (T2) can be controlled by the control device (µC) via the interface (P) through the fourth resistor (R4) and wherein a collector of the second transistor (T2) is connected to the third potential (G) via the fifth resistor (R5). [6] Device (1) according to claim 4 or 5, wherein - the first transistor (T1) is an NPN transistor, and - the second transistor (T2) is a PNP transistor. [7] System (2) for charging electrical energy storage devices (C1; C2), comprising a control device (µC) which is configured to control either fast charging of the energy storage devices (C1; C2) or slow charging of the energy storage devices (C1; C2). [8] System (2) according to claim 7, further comprising a device (1) for operating the electrical energy storage devices (C1; C2) according to any one of claims 1 to 6 for slowly charging the energy storage devices (C1; C2). [9] System (2) according to one of claims 7 or 8, further comprising a switch (8), a first diode (D1) and a second diode (D2), wherein a third potential (V3) is connected to the switch (8) via the first diode (D1), wherein the switch (8) is connected to a second potential (V2) via the second diode (D2) and wherein the control device (µC) is configured to control the switch (8) for fast charging of the energy storage devices (C1; C2). [10] System (2) according to claim 9, further comprising a sixth resistor (R6), a seventh resistor (R7) and a third diode (D3), wherein the first diode (D1) is connected to the third diode (D3) via the sixth resistor (R6), wherein the third diode (D3) is connected to the second potential (V2) via the seventh resistor (R7). [11] Locking system (10) for a vehicle (12), comprising - a system (2) according to any one of claims 7 to 10, - at least two electrical energy storage devices (C1; C2), - a voltage source (14) for supplying the energy storage devices (C1; C2) with electrical energy and - a locking device (16), - wherein the energy storage devices (C1; C2) are arranged to supply the locking device (16) with electrical energy.

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