System having an energy storage unit, charging station and monitoring device for monitoring a radio link between the energy storage unit and charging station, method for monitoring the radio link, computer program, and storage medium

Abstract

The invention relates to a system (1) comprising: an energy storage unit (2), which has a first communication device (4); and a charging station (6), which is designed to charge the energy storage unit (2) and has a second communication device (8). The first and second communication devices (4, 8) are designed to establish a radio link with one another. The system (1) also comprises a monitoring device (10), which is arranged in the energy storage unit (2) and / or the charging station (6) and has the following device functional regions: a detection region (11), which is designed to detect the presence and interruption of the radio link between the first and the second communication device (4, 8); and an output region (12), which is designed to output a warning signal if the interruption of the radio link is detected. The invention also relates to a method for monitoring the radio link, to a computer program, and to a computer-readable storage medium.

Description

[0001] Description

[0002] System comprising energy storage unit, charging station and monitoring device for monitoring a radio link between energy storage unit and charging station, method for monitoring the radio link, computer program and storage medium

[0003] The present disclosure relates to a system comprising an energy storage unit having a first communication device and a charging station configured for charging the energy storage unit and having a second communication device. The system further comprises a monitoring device for monitoring a radio link between the first communication device of the energy storage unit and the second communication device of the charging station. The present disclosure also relates to a method for monitoring the radio link, a computer program containing instructions for a computer to execute the method, and a computer-readable storage medium on which the computer program is stored.

[0004] An energy storage unit, also called an accumulator, for a surgical hand instrument is a known technology. During an operation, a surgical hand instrument powered by such an energy storage unit offers the user, e.g., a surgeon, the advantage of not being hindered by a power cable, thus enabling a more efficient and safer procedure.

[0005] Strict hygiene standards must be met during surgery. Surgical instruments must be sterile before use. Since surgical instruments are reusable, this means they must be cleaned and sterilized. This can be achieved, for example, by heating them to 121°C under high pressure in an autoclave.

[0006] Heating the energy storage unit in an autoclave inevitably leads to its destruction due to the high temperature. This destruction can also damage other devices inside the autoclave and / or the autoclave itself. Lithium-ion batteries, in particular, pose a high risk of fire and explosion.

[0007] It is therefore an object of the present invention to avoid or at least reduce the disadvantages of the prior art. In particular, it is intended to prevent the sterilization of an energy storage unit of a surgical hand instrument in an autoclave.

[0008] The objective of this disclosure is achieved by the subject matter of the dependent claims. Advantageous embodiments are the subject matter of the dependent claims and / or are illustrated in the following description and / or figures.

[0009] A system as disclosed comprises an energy storage unit having a first communication device, and a charging station configured for charging the energy storage unit and having a second communication device. The first and second communication devices are configured to establish a radio connection with each other. Furthermore, the system comprises a monitoring device arranged in the energy storage unit and / or the charging station. The monitoring device includes the following functional areas: a detection area configured to detect the presence and termination of the radio connection between the first and second communication devices; and an output area configured to output a warning signal when the termination of the radio connection is detected.

[0010] The term "energy storage unit" refers in particular to a portable, rechargeable energy storage device, also called a battery or accumulator, which can be inserted into and removed from a surgical hand instrument. The energy storage unit can be of one of the following types: lithium-ion battery, nickel-metal hydride battery (NiMH), or nickel-cadmium battery (NiCd). Preferably, the energy storage unit is a lithium-ion battery. The energy storage unit can be recharged in the corresponding charging station. The term "charging station" refers in particular to a device for charging the energy storage unit. The charging station can charge several energy storage units in parallel. The charging of the energy storage unit can be inductive or conductive.

[0011] The first communication device comprises a transmitting unit and / or a receiving unit. Preferably, the first communication device comprises both a transmitting unit and a receiving unit. Consequently, bidirectional data exchange is possible.

[0012] The second communication device comprises a transmitting unit and / or a receiving unit. Preferably, the second communication device comprises both a transmitting unit and a receiving unit. Therefore, bidirectional data exchange is possible.

[0013] The first communication device can be designed to establish the radio connection permanently or initially when the energy storage unit is removed from the charging station.

[0014] Functional domains can be implemented using hardware, software, and / or a combination thereof. Functional domains can be single-part or multi-part. Hardware devices, for example, can be implemented by processing circuits such as a processor, central processing unit (CPU), controller, arithmetic logic unit (ALU), digital signal processor, microcomputer, field-programmable gate array (FPGA), system-on-chip (SoC), programmable logic unit, microprocessor, or any other device capable of responding to instructions and executing them in a defined manner.

[0015] The functional areas may include one or more interface circuits. In some examples, the interface circuits may include wired or wireless interfaces connected to a local area network (LAN), the internet, a wide area network (WAN), or combinations thereof. The functionality of a particular device, functional area, or unit of this disclosure may be distributed among multiple units or devices connected via interface circuits.

[0016] The functional areas may also include one or more storage devices. The one or more storage devices may be physical or non-transient computer-readable storage media, such as random-access memory (RAM), read-only memory (ROM), a permanent mass storage device (e.g., a hard disk drive), a solid-state device (e.g., NAND flash), and / or any other data storage mechanism capable of storing and recording data. The one or more storage devices may be used to store computer programs, program code, instructions, or a combination thereof.

[0017] The term "detection range" in this context refers to a functional area designed to detect the presence of a radio connection, depending on the radio protocol and underlying technology used. For example, the underlying technology could be a wireless radio technology such as WLAN, Bluetooth, Bluetooth Low Energy, Zigbee, or Thread. In this case, the presence of a connection can be detected via a handshake process. This handshake process can involve the exchange of specific messages, such as connection requests and acknowledgments, between the first and second communication devices. Once such a handshake has been successfully completed, a radio connection is considered established. Alternatively or additionally, the charging station and / or energy storage unit can measure the signal strength of the received radio signal. If a certain signal strength threshold is exceeded, i.e.,A radio connection is assumed to exist when a threshold value is reached. The detection area is further developed to recognize when a radio connection is no longer present. Initially, the radio connection may be present. At a later point, depending on the radio technology used, it may be determined that a handshake was not successful or that the signal strength has fallen below a predetermined threshold. The term "output area" refers to a functional area configured to issue a warning signal when a radio connection interruption is detected. The warning signal can include at least one of the following: text message, audio message (announcement, alarm tone), or warning light. The warning signal can be sent to the charging station, a central display (screen in the operating room or preparation room), a mobile device (e.g., a smartphone), or a central computer for output.For example, a tone and a corresponding text message sound on a central display, indicating the danger that the radio connection has been lost and the medical device may be en route to the autoclave. Preferably, the output unit itself can also include means for emitting the warning signal. Accordingly, the energy storage device and / or the charging station itself can emit the warning signal. Examples of such means include a loudspeaker, a visual display (e.g., an LED display), and a vibration device. Consequently, different types of warning signals, provided by a combination of these means, can also be emitted, as described below.

[0018] The above system is based on the understanding that an energy storage unit must be removed from a surgical hand instrument after an operation in the operating room, so that it remains in a so-called supply area (usually an anteroom to the operating room). There, it is recharged and can be used for the next operation. The surgical hand instrument is placed in an autoclave in a Central Sterile Supply Department (CSSD). In the autoclave, the surgical hand instrument is sterilized under pressure and at a temperature of at least 121 °C. If an energy storage unit remains in the surgical hand instrument, there is a risk of thermal runaway or deflagration due to overheating. This can damage the energy storage unit, the autoclave, and the other equipment in the autoclave. Lithium-ion batteries, in particular, tend to thermal runaway or even explode when exposed to heat.

[0019] Equipped with communication devices (i.e., transmitter and receiver), the charging station and energy storage unit can establish a radio link. When a radio link is established, the energy storage unit is presumed to be located in the service area or the adjacent operating room. If the radio link is lost, the energy storage unit is presumed to be outside these two areas (i.e., outside the usual working environment) and on its way to the autoclave. The monitoring device then issues a warning signal to indicate the hazard described above. This has a beneficial effect on the safety and lifespan of the energy storage unit, the autoclave, and the other equipment within the autoclave.

[0020] According to one aspect, the energy storage unit can be designed to supply energy to a surgical hand instrument, and the charging station can be positioned in a supply tract to an operating room.

[0021] The term "surgical hand instrument" in this context refers specifically to battery-powered surgical hand instruments, which can be designed for various surgical applications and operated with a rechargeable energy storage unit. Examples of surgical hand instruments include: drills, saws, cautery, patient monitors, infusion pumps, defibrillators, blood pressure monitors, and infusion pumps. Surgical hand instruments offer a high degree of mobility and flexibility because they can be operated independently of a fixed power source.

[0022] According to one aspect, the radio connection can be based on Bluetooth, especially Bluetooth Low Energy.

[0023] This wireless connection can advantageously operate with reduced power consumption. This can have a beneficial effect on the operating time of the energy storage unit.

[0024] According to one aspect, the monitoring device can further comprise: a provisioning area configured to provide an initial time setting; and a measuring area configured to measure the initial time interval between the detection of a radio connection interruption. The output area can then be configured to only issue the warning signal when the measured initial time interval is greater than the initial time setting. In this context, the term provisioning area refers to a functional area configured to provide a predetermined value, in this case, a time setting. The predetermined value can be changed by a user according to their preferences. This can be done, for example, via an external device (e.g., a smartphone) that establishes a radio connection with the first or second communication device.

[0025] The term measuring range, in this case, refers to a functional range that is set up to measure a time from a specific event, here the interruption of the radio connection.

[0026] The initial timeout can be set to, for example, 5 seconds. If the radio connection is lost and no new connection is established within this timeframe, the monitoring device assumes that the energy storage unit is en route to the autoclave. This timeout allows for the consideration of unintended interference with the radio connection, which would otherwise lead to false alarms and corresponding warning signals. In this way, the probability of false alarms can be reduced, thus increasing the reliability of the monitoring device.

[0027] According to one aspect, the provisioning area can be configured to provide a second time setting. Furthermore, the measuring area can be configured to measure a second time interval after the detection of the radio connection. Additionally, the output area can be configured to issue a warning signal if the measured second time interval is longer than the second time setting.

[0028] The second time limit can be, for example, 20 minutes. Normally, the duration of use of the surgical hand instrument during an operation is 15 minutes or less. As soon as the second time period exceeds the second time limit without a continuous interruption of the radio connection, the monitoring device assumes that the power storage unit has been left in the operating room. The warning signal then issued can include the information that the power storage unit has been left in the operating room. The monitoring device can also be further configured to detect when the power storage unit is plugged into the charging station, so that no warning signal is sent if the measured second time period is longer than the second time limit. For this purpose, the charging station can, for example, send a signal to the monitoring device when the power storage unit is plugged in.Alternatively or additionally, the measuring range can be configured to only measure the second time interval once the energy storage unit is removed from the charging station. This is particularly advantageous if the radio link between the first and second communication devices is permanently established, i.e., even when the energy storage unit is plugged into the charging station.

[0029] This system can advantageously detect if the energy storage unit is left behind in the operating room. The warning signal alerts a staff member, who can then locate the unit and place it in the charging station. This increases the availability of charged energy storage units.

[0030] According to one aspect, the detection area can be configured to detect the signal strength of the radio link. The provisioning area can be configured to provide an initial signal strength threshold. The monitoring device can further include a comparison area configured to compare the signal strength of the radio link with the initial signal strength threshold. The output area can then be configured to send a warning signal if the detected signal strength is lower than the initial signal strength threshold.

[0031] The detection area preferably measures the received signal strength (RSSI) of the radio signals received by the charging station or energy storage unit. Preferably, the detection area measures the received signal strength of the charging station. The measurement can be performed continuously in real time, providing a corresponding value, or it can be averaged after a predetermined period (e.g., 2 seconds). The detection area can communicate with the communication device to measure the received signal strength. The comparison area refers to a functional area configured to compare the measured signal strength with the first signal strength threshold. If the measured signal strength of the received radio signals falls below the first signal strength threshold, a radio connection is assumed to have been lost, and vice versa.The output area then emits a warning signal. The first signal strength threshold can be set according to the area where the energy storage unit is usually located, e.g., the service area and the operating room. This means that the first signal strength threshold can be set such that if the detected signal strength exceeds this threshold, it can be assumed that the energy storage unit has left the area, such as the service area and the operating room.

[0032] In this way, the presence and termination of a radio connection can be advantageously detected precisely. In particular, by setting the first signal strength threshold to a predefined area, such as the service area and the operating room, it can be reliably determined that the energy storage unit is outside this area and, if applicable, on its way to the autoclave.

[0033] According to one aspect, the detection area can be configured to detect the signal strength of the radio link between the first and second communication devices. The provisioning area can be configured to provide a second signal strength threshold, a third signal strength threshold that is lower than the second threshold, and a third time limit. The comparison area can be configured to compare the signal strength of the radio link with the second and third signal strength thresholds. The measurement area can be configured to measure a third time interval between falling below the second signal strength threshold and reaching the third signal strength threshold. The output area can be configured to output a warning signal if the third time interval is less than the third time limit.The second signal strength threshold refers specifically to a signal strength threshold above which a received signal strength indicates good to very good radio link quality. The third signal strength threshold refers specifically to a signal strength threshold below which no radio link exists. This threshold can be zero or defined arbitrarily to account for ambient noise or interference. The third time limit refers specifically to a very short time limit. By specifying the two signal strength thresholds and a time limit for signal strength drop, the system addresses the situation where the energy storage unit is abruptly removed from the vicinity of the charging station, e.g., the supply area and the operating room, and the radio link is therefore interrupted. This situation is intended to indicate that the energy storage unit is en route to the autoclave.

[0034] According to one aspect, the provisioning area can be configured to provide a fourth time interval and a state-of-charge threshold. The measuring area can be configured to measure a fourth time interval from the detection of the radio connection. The detection area can be configured to detect the state of charge of the energy storage unit. The comparison area can be configured to compare the detected state of charge with a state-of-charge threshold. The output area can be configured to output a warning signal if the measured fourth time interval exceeds the fourth time interval and the detected state of charge is less than the signal strength threshold.

[0035] The fourth time setting refers to a longer period, for example, two hours. The charge level refers to the state of charge of the energy storage unit. A unit for measuring the charge level can be integrated into the energy storage unit. The charge level can, for example, indicate the percentage to which the energy storage unit is charged. The monitoring device measures the duration of a radio connection and, from a certain point onward, compares the charge level of the energy storage unit with a charge level threshold (for example, 30%) and issues a warning signal if the charge level falls below the threshold. In this way, an additional check of the charge level can be advantageously monitored in relation to the duration of a radio connection.This allows the energy storage unit to be charged in time and also prevents false alarms due to an empty energy storage unit and a corresponding interruption of the radio connection.

[0036] According to one aspect, the detection area can be configured to detect the position of the energy storage unit using a positioning system. The positioning system can be, in particular, a GPS tracker and / or a radio-based positioning system. The output area can then be configured to output the detected position, in particular via the first communication device.

[0037] The recorded location can be transmitted, for example, to a mobile device (e.g., a smartphone) that has established a communication link with the first communication device, allowing a user to search for and locate the energy storage unit. To locate the energy storage unit, the first communication device can establish a wireless connection with other devices in the hospital that also have a compatible communication device. This creates a wireless network within the hospital that can be used to locate the energy storage unit. This method advantageously facilitates the location of the energy storage unit.

[0038] A disclosed method for monitoring a radio link between a first communication device of an energy storage unit and a second communication device of a charging station designed to charge the energy storage unit comprises the following steps: detecting the existence of the radio link; detecting a termination of the radio link; and issuing a warning signal when a termination of the radio link is detected.

[0039] The disclosed method can be further developed according to the aspects of the system described above. Consequently, the method can provide the same advantages as the system described above. A computer program according to the disclosure contains instructions which, when executed by a computer, cause it to execute the disclosed method.

[0040] A computer-readable storage medium as disclosed stores the computer program as disclosed.

[0041] The present revelation will be explained below with reference to the figures. They show

[0042] Fig. 1 is a schematic representation of a system according to the revelation,

[0043] Fig. 2 shows a schematic situation for the proper handling of an energy storage unit, and

[0044] Fig. 3 shows a schematic situation for improper handling of the energy storage unit.

[0045] Figure 1 shows a system 1 comprising an energy storage unit 2 with a first communication device 4 and a charging station 6 with a second communication device 8. The first and second communication devices 4, 8 are configured to establish a radio connection for bidirectional data exchange. The communication is based, in particular, on Bluetooth Low Energy. The radio connection can be established permanently or only when the energy storage unit 2 is removed from the charging station 6.

[0046] System 1 further comprises a monitoring device 10, which is preferably arranged in the energy storage unit 2 and the charging station 6. However, it is also conceivable that the monitoring device 10 is arranged only in the energy storage unit 2 or the charging station 6. It is preferred that the monitoring device 10 is arranged in the charging station. The monitoring device 10 comprises a detection area 11, an output area 12, a provision area 13, a measuring area 14, and a comparison area 15 as functional areas of the device. The detection area 11 is configured to detect the presence and termination of the radio connection between the first and the second communication devices 4, 8. The output area 12 is configured to output a warning signal when the termination of the radio connection is detected. Figure 1 shows an example of the output of an acoustic warning signal.However, it is also conceivable to output an optical or haptic signal, such as a vibration signal. If the monitoring device 10 is located in both the energy storage unit 2 and the charging station 6, different warning signals can be output. For example, the charging station 6 can output an acoustic warning signal, while the energy storage unit 2 outputs a vibration signal.

[0047] According to one embodiment, the detection area 11 can be configured to detect the signal strength of the radio link. The provisioning area 13 can be configured to provide a first signal strength threshold. The comparison area 15 can be configured to compare the signal strength of the radio link with the first signal strength threshold. The output area 12 can then be configured to output a warning signal if the detected signal strength is less than the first signal strength threshold.

[0048] According to another embodiment, the provisioning area 13 can be configured to provide an initial time setting. The measuring area 14 can be configured to measure an initial time interval from the detection of the radio connection interruption. The output area 12 can be configured to output the warning signal only when the measured initial time interval is greater than the initial time setting.

[0049] According to a further embodiment, the provisioning area 13 can be configured to provide a second time setpoint. The measuring area 14 can be configured to measure a second time interval from the detection of the radio connection. The output area 12 can be configured to output a warning signal if the measured second time interval is greater than the second time setpoint. To prevent unnecessary warning output, the output area 12 can be configured to output a warning signal only if the energy storage unit 2 is not in the charging station 6. The monitoring device 10 can be configured to detect when the energy storage unit 2 is plugged into the charging station 6 for charging. Alternatively or additionally, the measuring area 14 can be configured to measure the second time interval only after the energy storage unit 2 has been removed from the charging station 6.This approach is particularly advantageous if the radio connection between the first communication device 4 and the second communication device 8 is permanently established, i.e., even when the energy storage unit 2 is plugged into the charging station 6.

[0050] According to an additional embodiment, the detection area 11 can be configured to detect the signal strength of the radio link between the first communication device 4 and the second communication device 8. The provision area 13 can be configured to provide a second signal strength threshold, a third signal strength threshold that is lower than the second signal strength threshold, and a third time limit. The comparison area 15 can be configured to compare the signal strength of the radio link with the second signal strength threshold and the third signal strength threshold. The measuring area 14 can be configured to measure a third time interval between falling below the second signal strength threshold and reaching the third signal strength threshold. The output area 12 can be configured to output a warning signal if the third time interval is less than the third time limit.

[0051] According to a further embodiment, the provisioning area 13 can be configured to provide a fourth time interval and a charge level threshold. The measuring area 14 can be configured to measure a fourth time interval from the detection of the radio connection. The detection area 11 can be configured to detect the charge level of the energy storage unit 2. The comparison area 15 can be configured to compare the detected charge level with a charge level threshold. The output area 12 can be configured to output a warning signal if the measured fourth time interval exceeds the fourth time interval and the detected charge level is lower than the signal strength threshold. It should be noted that the described embodiments can be combined with one another.In order to enable a distinction between the individual cases of the embodiment, the output area 12 can be designed to output different warning signals depending on the detected case.

[0052] An embodiment is described below with reference to Figures 2 and 3, in which the energy storage unit 2 is designed to supply energy to a surgical hand instrument 18. The charging station 6 is then positioned in a supply tract 20 to an operating room.

[0053] Fig. 2 shows a schematic diagram of the proper handling of the energy storage unit 2. The energy storage unit 2 is initially located in a surgical hand instrument 18, in this case a drill, within a supply tract 20. The energy storage unit 2 is in radio communication with the charging station 6. The monitoring device 10 described above is integrated into the charging station 6. In this scenario, the energy storage unit 2 is detached from the surgical hand instrument 18 after the operation; that is, it is removed and properly charged by the charging station 6. To remove the energy storage unit 2, a handpiece 22 and a cover 24 of the surgical hand instrument 18 can be separated. The surgical hand instrument 18, i.e., handpiece 22 and cover 24, is then transported in a sterile container 28 to a central sterile supply department (CSSD) 30.In the CSSD 30, the surgical hand instrument 18 is then sterilized in an autoclave (not shown). In this situation, no warning signal is sent.

[0054] Fig. 3 shows a schematic scenario of improper handling of the energy storage unit 2. In contrast to Fig. 2, the energy storage unit 2 is not detached from the surgical hand instrument 18. It remains inside the surgical hand instrument 18, which is then transported by personnel 26 in a sterile container 28 to the CSSD 30. Consequently, the radio connection between the energy storage unit 2 and the charging station is interrupted. Upon detecting the interruption of the radio connection between the energy storage unit 2 and the charging station 6, as exemplified in Fig. 3, the monitoring device 10 of the charging station emits an audible warning signal. As a result, trained operating room personnel in the supply area are alerted to the removal of the energy storage unit 2 and can stop the personnel 26. This prevents the energy storage unit 2 from entering the autoclave (not shown) and causing damage.

[0055] Reference symbol list

[0056] 1 system

[0057] 2 Energy storage units

[0058] 4 first communication device

[0059] 6 charging stations

[0060] 8 second communication device

[0061] 10 Monitoring device

[0062] 11. Detection area

[0063] 12 Output area

[0064] 13 Deployment area

[0065] 14 Measuring range

[0066] 15 Comparison range

[0067] 18 surgical hand instruments

[0068] 20 Supply wing

[0069] 22 Handpiece

[0070] 24 lids

[0071] 26 staff

[0072] 28 sterile containers

[0073] 30 Central Sterile Supply Department

Claims

Claims 1. System (1) comprising: an energy storage unit (2) comprising a first communication device (4); and a charging station (6) configured for charging the energy storage unit (2) and comprising a second communication device (8); wherein the first and second communication devices (4, 8) are configured to establish a radio connection with each other; and a monitoring device (10) arranged in the energy storage unit (2) and / or the charging station (6) comprising the following device functional areas: a detection area (11) configured to detect the presence and termination of the radio connection between the first and the second communication device (4, 8); and an output area (12) configured to output a warning signal when the termination of the radio connection is detected.

2. System (1) according to claim 1, wherein the energy storage unit (2) is designed to supply energy to a surgical hand instrument (22), and the charging station (6) is positioned in a supply tract (20) to an operating room.

3. System (1) according to any of the preceding claims, wherein the radio connection is based on Bluetooth, in particular Bluetooth Low Energy.

4. System (1) according to one of the preceding claims, wherein: the monitoring device (10) further comprises: a provision area (13) configured to provide a first time setpoint; and a measuring area (14) configured to measure a first time interval from the detection of the termination of the radio connection; and the output area (12) is designed to only output the warning signal when the measured first time interval is greater than the first time specification.

5. System (1) according to one of the preceding claims, wherein: the provision area (13) is configured to provide a second time specification; the measuring area (14) is configured to measure a second time interval from the detection of the existence of the radio connection; and the output area (12) is configured to output a warning signal if the measured second time interval is greater than the second time specification.

6. System (1) according to one of the preceding claims, wherein: the detection area (11) is configured to detect a signal strength of the radio link; the provision area (13) is configured to provide a first signal strength threshold; the monitoring device (10) has a comparison area (15) configured to compare the signal strength of the radio link with the first signal strength threshold; and the output area (12) is configured to output a warning signal when the detected signal strength is less than the first signal strength threshold.

7. System (1) according to claim 6, wherein the provision area (13) is configured to set the first signal strength limit value according to an area in which the energy storage unit (2) is usually located, in particular the supply tract (20) and the operating room.

8. System (1) according to one of the preceding claims, wherein: the detection area (11) is configured to detect a signal strength of the radio link between the first communication device (4) and the second communication device (6); the provisioning area (13) is configured to provide a second signal strength limit, a third signal strength limit which is lower than the second signal strength limit, and a third time limit; the comparison area (15) is configured to compare the signal strength of the radio link with the second signal strength limit and the third signal strength limit; the measurement area (14) is configured to measure a third time interval from falling below the second signal strength limit to reaching the third signal strength limit; and the output area (12) is configured to output a warning signal when the third time interval is less than the third time limit.

9. System (1) according to one of the preceding claims, wherein: the provision area (13) is configured to provide a fourth time setpoint and a state-of-charge limit; the measuring area (14) is configured to measure a fourth time interval from the detection of the existence of the radio connection; the detection area (11) is configured to detect a state of charge of the energy storage unit (2); the comparison area (15) is configured to compare the detected state of charge with a state-of-charge limit; and the output area (12) is configured to output a warning signal if the measured fourth time interval exceeds the fourth time setpoint and the detected state of charge is less than the state-of-charge limit.

10. System (1) according to one of the preceding claims, wherein: the detection area (11) is configured to detect a position of the energy storage unit (2) using a positioning system, in particular a GPS tracker and / or a positioning system based on a radio connection; and the output area (12) is configured to output the detected position.

11. Method for monitoring a radio link between a first communication device (4) of an energy storage unit (2) and a second communication device (8) of a charging station (6) configured for charging the energy storage unit (2), the method comprising the following steps: Determining the existence of a radio connection; Detecting a radio connection interruption; Issue a warning signal when a loss of radio connection is detected.

12. Computer program comprising instructions which, when executed by a computer, cause the computer to execute the method according to claim 11.

13. Computer-readable storage medium in which the computer program according to claim 12 is stored.

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