Adaptive control for a combination of storage batteries

Abstract

A method for controlling and adjusting a system comprising at least a first storage battery with a first transceiver and a first storage unit, a second storage battery with a second transceiver and a second storage unit, a first charging device with a third transceiver, and s second charging device with a fourth transceiver, each storage battery being equipped with at least one sensor for measuring at least one parameter. A system for carrying out the method, comprising at least a first storage battery and a second storage battery, at least a first charging device and a second charging device, and at least a first machine tool and a second machine tool, the first and second storage batteries each being equipped with a first transceiver and a first storage unit, the first and second charging devices each being equipped with a second transceiver and a second storage unit, and the first and second machine tools each being equipped with a third transceiver and a third storage unit.

Description

[0001] Adaptive control for a network of accumulators

[0002] The present invention relates to a method for controlling and regulating a system comprising at least a first accumulator with a first transceiver and a first storage unit, a second accumulator with a second transceiver and a second storage unit, a first charging device with a third transceiver and a second charging device with a fourth transceiver, wherein each accumulator contains at least one sensor for detecting at least one parameter.

[0003] Furthermore, the invention relates to a system for carrying out the method comprising at least a first and a second accumulator, at least a first and a second charging device and at least a first and a second machine tool, wherein the first and the second accumulator each contain a first transceiver and a first storage unit, the first and the second charging device each contain a second transceiver and a second storage unit and the first and the second machine tool each contain a third transceiver and a third storage unit.

[0004] Accumulators (also called batteries) as power supplies for machine tools are widely known in the art. These accumulators typically contain a number of energy storage cells (also called battery cells) that are designed and used to absorb, store, and release electrical energy. The absorption of electrical energy into the energy storage cells can also be referred to as charging. The release of electrical energy from the energy storage cells can also be referred to as discharging.

[0005] To charge or recharge with electrical energy, the battery is usually connected to a charging device (also called a charger). The charging device supplies electrical energy to the individual energy storage cells of the battery according to a predetermined charging setting (also called charging mode) with fixed parameters for the actual charging process.

[0006] To achieve near-optimal charging of a battery with electrical energy and near-optimal discharging of the battery (i.e., the re-release of the energy stored in the battery to, for example, a machine tool), the battery parameters should be between minimum and maximum thresholds. Operating a battery, i.e., charging and discharging, outside of these thresholds can lead to significantly longer charging times, lower capacity, and / or a lower discharge current.

[0007] Maintaining the battery parameters within the ideal range or between the threshold values ​​is difficult, especially when the batteries are used outdoors and in extreme weather conditions.

[0008] The object of the present invention is to solve the problem described above.

[0009] The object is also achieved by the subject matter of claim 1 and by the subject matter of claim 4. Further advantageous embodiments of the invention are described in the corresponding subclaims.

[0010] The object is achieved in particular by a method for controlling and regulating a system comprising at least a first accumulator with a first transceiver and a first storage unit, a second accumulator with a second transceiver and a second storage unit, a first charging device with a third transceiver and a second charging device with a fourth transceiver, wherein each accumulator contains at least one sensor for detecting at least one parameter.

[0011] According to the invention, the following process steps are provided

[0012] - detecting at least one operating characteristic value by the at least one sensor of a respective accumulator;

[0013] - connecting the at least first accumulator to the first charging device and connecting the at least second accumulator to the second charging device;

[0014] - transmitting at least one operating characteristic value of the first accumulator detected by the sensor from the first accumulator to the first charging device before the start of a charging process and transmitting at least one operating characteristic value of the second accumulator detected by the sensor from the second accumulator to the second charging device before the start of a charging process;

[0015] - Sending the at least one operating characteristic value of the first accumulator from the first charging device to a data storage and computing device, and sending the at least one operating characteristic value of the second accumulator from the second charging device to the data storage and computing device; - Comparing the parameters of the first and second accumulators with threshold values ​​stored in the data storage and computing device;

[0016] - comparing the respective operating parameters with a threshold value stored in the data storage and computing device;

[0017] - Sending at least one second control parameter from the data storage and computing device via the charging device to the first and / or second accumulator to replace a first control parameter stored accordingly in the first and / or second accumulator if, for a predetermined period of time and amount, at least one operating characteristic exceeds a threshold value stored in the data storage and computing device; and

[0018] - Charging at least one accumulator with electrical energy by the charging device with at least the second control parameter.

[0019] According to an advantageous embodiment, it may be possible that the method steps

[0020] - transmitting at least one first control parameter of the accumulator from the accumulator to the charging device before the start of a charging process.

[0021] According to an advantageous embodiment, it may also be possible for the method steps

[0022] - connecting the at least first or second accumulator to a machine tool;

[0023] - supplying the machine tool with electrical energy by discharging at least the first or second accumulator with at least the second control parameter.

[0024] The object is further achieved by a system for carrying out the method, comprising at least a first and a second rechargeable battery, at least a first and a second charging device, and at least a first and a second machine tool, wherein the first and a second rechargeable battery each contain a first transceiver and a first storage unit, the first and a second charging device each contain a second transceiver and a second storage unit, and the first and a second machine tool each contain a third transceiver and a third storage unit. Further advantages will emerge from the following description of the figures. A particularly preferred exemplary embodiment of the present invention is shown in the figure. The figures, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form useful further combinations.

[0025] In the figure, identical and similar components are numbered with the same reference numerals.

[0026] It shows:

[0027] Figure 1 is a side view of a machine tool with an accumulator according to a first embodiment;

[0028] Figure 2 is a perspective view of an interface of the machine tool;

[0029] Figure 3 is a perspective view of the accumulator;

[0030] Figure 4 perspective view of a loading device; and

[0031] Figure 5 is a schematic view of a system comprising a first machine tool with a first accumulator, a second machine tool with a first accumulator, a third machine tool with a third accumulator, a first charging device to which the first accumulator can be connected, a second charging device to which the second accumulator can be connected, a third charging device to which the third accumulator can be connected, and a data storage and computing device.

[0032] Examples of implementation:

[0033] Figure 5 shows a system S with a first, second, and third machine tool 1a, 1b, 1c, each connected to a first, second, and third accumulator 2a, 2b, 2c, as well as a first, second, and third charging device 22a, 22b, 22c. The machine tools 1a, 1b, 1c, accumulators 2a, 2b, 2c, and charging devices 22a, 22b, 22c are essentially structurally identical in the present embodiment.

[0034] Alternatively, the system S may contain more or fewer than three machine tools, loading devices and accumulators.

[0035] In the present embodiment, the machine tools 1a, 1b, 1c are configured, for example, as cordless screwdrivers. The machine tools 1a, 1b, 1c can also be configured as drills, hammer drills, saws, grinders, or the like.

[0036] As indicated in Figure 1, each machine tool 1a, 1b, 1c essentially contains a housing 3, a handle 4 and a tool holder 5. Inside the housing 3, a drive 6 in the form of an electric motor, a gear device 7, an output shaft 8, a control unit 9, a storage unit 10 and a transceiver 11 are positioned.

[0037] The drive 6, designed as an electric motor, the transmission device 7, and the output shaft 8 are arranged relative to one another such that a torque generated by the electric motor 6 can be transmitted to the tool holder 5 via the output shaft 8 and the transmission device 7. The tool holder 5 is positioned at a front end 3a of the housing 3 and is designed to receive and hold a tool. In the case of a cordless screwdriver, the tool can be designed as a screwdriver bit. The tool is not shown in the figures.

[0038] The handle 4 is positioned on a bottom side 3b of the housing 3. The handle 4 is fastened with a first end 4a to the bottom side 3b of the housing 3. A machine tool interface 12 is positioned at a second end 4b of the handle 4 and serves for the electrical or electronic as well as mechanical connection of the machine tool 1 with the accumulator 2. For the electrical or electronic connection, the

[0039] Machine tool 1 has a positive contact 13a, a negative contact 13b and a

[0040] Communication contact 13c. The positive and negative contacts 13a, 13b serve to create an electrical circuit when the accumulator 2 is connected to the machine tool 1. The communication contact 13c serves to send and receive data and information in the form of electrical signals.

[0041] An actuation switch 14 is provided at a front end 4c of the handle 4. The actuation switch 14 serves to activate the machine tool 1. The control unit 9 with the transceiver 11 and the storage unit 10 is positioned inside the handle 4. The control unit 9 controls and regulates the individual functions of the machine tool 1. These functions include, for example, setting a specific speed of the electric motor 6.

[0042] The accumulator 2 can be releasably connected to a machine tool 1 in order to supply the machine tool 1 with electrical energy.

[0043] Each accumulator 2 essentially contains a battery housing 15, a number of energy storage cells 16, a battery interface 17, a storage unit 18, a transceiver 19, a control device 20 and a plurality of sensors.

[0044] The energy storage cells 16 can also be referred to as battery cells and are arranged inside the battery housing 15.

[0045] The battery housing 15 essentially contains a cover element 15a, four side walls 15b and a base element 15c.

[0046] The battery interface 17 is arranged on the outside of the cover element 15a and serves for the electrical or electronic as well as mechanical connection of the battery 2 to the machine tool 1 or a charging device 22.

[0047] For electrical or electronic connection, the battery interface 17 has a positive contact 17a, a negative contact 17b, and a communication contact 17c. The positive and negative contacts 17a, 17b serve to create an electrical circuit when the battery 2 is connected to a machine tool 1 or a charging device 22. The communication contact 17c serves to send and receive data and information in the form of electrical signals.

[0048] Alternatively or additionally, the accumulator 2 may also contain radio communication (e.g. Bluetooth) or wireless communication.

[0049] The energy storage cells 16 serve to absorb, store, and re-release electrical energy. As indicated in the figures, the energy storage cells 16 are cylindrical in shape and based on lithium-ion technology. Each energy storage cell 16 contains a contact device at one end, which serves to transmit electrical energy. The individual contact devices are connected to the control device 20 of the accumulator 2 via corresponding lines.

[0050] Alternatively, the energy storage cells 16 can also be based on another suitable technology. The cylindrical shape of the energy storage cells 16 is also optional, so any other suitable shape or geometry can be selected. In particular, it is also possible for the energy storage cells to be designed as pouch cells.

[0051] It is also possible for the accumulator 2 to contain both cylindrical energy storage cells and pouch cells. In particular, it is possible for the accumulator 2 to contain only a single cylindrical energy storage cell 16 and a single pouch cell.

[0052] The control device 20 regulates and controls various functions of the accumulator 2. These functions include, among others, controlling the absorption and release of electrical energy into and from the energy storage cells 16. Furthermore, the control device 20 is used to control the amount of electrical energy to be absorbed or released by the energy storage cells 16.

[0053] A first control parameter set containing a plurality of control parameters is stored in the memory unit 18. The control parameters can also be referred to as control parameters or setting parameters.

[0054] The storage unit 18 is connected to the control device 20 in such a way that the control device 20 can access the individual control parameters stored in the storage unit 18 and, based on these control parameters, can control or regulate the functions of the accumulator 2. The control parameters include maximum discharge currents (current value), maximum charging currents (current value), minimum and maximum charging times, minimum and maximum internal resistances, and minimum and maximum capacity values ​​(in Ah).

[0055] The control parameters also include methods for reducing or completely blocking the energy absorption or release by the energy storage cells 16 in the event of a maximum acceleration value or braking value, a predetermined number of braking values ​​within predetermined threshold values, and minimum and maximum temperature values.

[0056] The accumulator 2 also contains a sensor for recording operating parameters. These operating parameters can also be referred to as operating parameters, operating variables, or operating variables.

[0057] In particular, the accumulator 2 contains a sensor for detecting a charging current and a discharging current 30, a sensor for detecting a charging time 31, a sensor for detecting an acceleration value and a braking value 32, a sensor for detecting temperature values ​​33, a sensor for detecting internal resistance values ​​34, a sensor for detecting the capacity 35 and a counter 36 for the number of acceleration values ​​which exceed a predetermined threshold value.

[0058] The sensor for detecting a charging time 31 can also be called a clock or real-time clock.

[0059] The acceleration value can be referred to as a value for positive acceleration and the braking value can also be referred to as a value for negative acceleration.

[0060] The sensor for detecting temperature values ​​33 can also be called a thermometer or temperature meter.

[0061] The sensor for detecting internal resistance values ​​34 can also be called an ohmmeter.

[0062] The capacity sensor 35 can also be called the ampere-hour (Ah) sensor.

[0063] According to an alternative embodiment of the system or the accumulator 2, it is possible for more or fewer sensors to be included in the accumulator 2.

[0064] Figure 4 shows a charging device 22, which essentially includes a charger housing 23, a control unit 24, a transceiver 25, a storage unit 26, and a power supply 27. The charger housing 23 essentially includes a cover element 23a, four side walls 23b, and a base element 23c.

[0065] A charger interface 28 is positioned on the cover element 23a and serves to electrically or electronically connect the charging device 22 to the accumulator 2. For electrical or electronic connection, the charger interface 28 has a positive contact 28a, a negative contact 28b, and a communication contact 28c. The positive and negative contacts 28a, 28b serve to create an electrical circuit when the accumulator 2 is connected to the charging device 22. The communication contact 28c serves to send and receive data and information in the form of electrical signals.

[0066] Alternatively or additionally, the charging device 22 may also include radio communication (e.g., Bluetooth) or wireless communication.

[0067] The power supply 27 is designed in the form of a power cable for connection to a mains power source (ie socket) not shown.

[0068] The control unit 24, the transceiver 25, and the storage unit 26 are located inside the charger housing 23. The control unit 24 controls and regulates the individual functions of the charging device 22. These functions include, among others, setting a charging current (i.e., the current value) when a rechargeable battery 2 is detachably connected to the charging device 22 for charging. The transceiver 25 is used to transmit and receive data and information in the form of electrical signals.

[0069] As indicated in Figure 5, the charging device 22 is particularly designed to exchange data and information with a data storage and computing device 29. The data storage and computing device 29 contains a transceiver 37, a computing unit 38, and a memory unit 39.

[0070] The data storage and computing device 29 can also be referred to as a cloud or cloud computer.

[0071] To carry out the method, the accumulator 2 is first connected to the machine tool 1 so that electrical energy can be transferred from the energy storage cell 16 to the consumers of the machine tool 1, see Figure 1. The respective interfaces of the accumulator 2 and the machine tool 1 are detachably connected to one another. By connecting the accumulator 2 to the machine tool 1, data and information in the form of electrical signals can also be exchanged between the accumulator 2 and the machine tool 1. The respective transceivers 19, 25 and the interconnected communication contacts 13c, 17c of the accumulator 2 and the

[0072] Machine tool 1.

[0073] During use of the accumulator 2 as a power supply for the machine tool 1, the sensors of the accumulator 2 record the various operating parameters mentioned above. It is possible that only some of the sensors record data. The operating parameters recorded by the sensors are stored in the memory unit.

[0074] As indicated in Figure 5, a rechargeable battery 2 can be removed from a respective machine tool 1 and releasably connected to a charging device 22. The energy storage cells 16 of the rechargeable battery 2 can be charged with electrical energy using the charging device.

[0075] In the present embodiment, it is indicated that the first, second, and third accumulators 2a, 2b, 2c are removed simultaneously from the respective machine tools 1a, 1b, 1c and connected to the respective charging devices 22a, 22b, 22c. However, it is also possible for the accumulators 2a, 2b, 2c to be removed from the machine tools and not simultaneously with the charging devices. The removal of the individual accumulators 2a, 2b, 2c from the machine tools 1a, 1b, 1c and the connection of the individual accumulators 2a, 2b, 2c to the respective charging devices 22a, 22b, 22c can be performed separately for each accumulator 2a, 2b, 2c, so that the removal of all accumulators 2a, 2b, 2c from the machine tools 1a, 1b, 1c and the connection to the charging devices 22a, 22b, 22c can take place within a specific period of time. This period can be several hours or days.

[0076] It is also possible for more than one battery to be repeatedly connected to a single charging device.

[0077] Furthermore, it is also possible for an accumulator 2a, 2b, 2c to be alternately connected to different charging devices 22a, 22b, 22c.

[0078] The respective interfaces of the rechargeable battery 2a, 2b, 2c and the charging device 22a, 22b, 22c are detachably connected to one another such that the respective communication contacts 17c, 28c of the rechargeable battery 2 and the charging device 22 are in contact with one another. By connecting the rechargeable battery 2 to the charging device 22, data and information in the form of electrical signals can also be exchanged between the rechargeable battery 2 and the charging device 22. The respective transceivers 19, 25 of the rechargeable battery 2 and the charging device 22 are used to transmit and receive the electrical signals.

[0079] Before the actual charging process begins, i.e. before electrical energy reaches the energy storage cells 16 of the accumulator 2 from the charging device 22, the accumulator 2 sends the operating parameters stored in the storage unit 18 to the charging device 22 using the transceivers 19, 25 and communication contacts 17c, 28c.

[0080] It is possible that only a single operating characteristic value is sent to the charging device 22, even if more than one operating characteristic value was detected by the sensors.

[0081] The charging device 22 stores the received operating parameters in the storage unit 26 of the charging device 22.

[0082] When the charging device 22 is connected to the data storage and computing device 29, the operating parameters are sent to the data storage and computing device 29. Each charging device 22 sends received operating parameters to the data storage and computing device 29 as soon as the corresponding charging device 22 is connected to the data storage and computing device 29.

[0083] In the data storage and computing device 29, threshold values ​​for the corresponding operating parameters are stored, which are detected by the sensors of the accumulator 2.

[0084] Furthermore, individual control parameters as well as complete control parameter sets for a plurality of different accumulators 2 are stored in the data storage and computing device 29.

[0085] In the data storage and computing device 29, a predetermined set of operating parameters of the same category is collected for a predetermined period of time. Collecting operating parameters of the same category within a certain period of time serves to provide the most comprehensive representation possible of the respective operating states of all accumulators 2a, 2b, 2c belonging to system S. The larger the set of collected operating parameters, the clearer the representation and interpretation of the respective operating states of the accumulators 2a, 2b, 2c can be. The predetermined period of time can be hours or days. The predetermined set or number of operating parameters can be dozens or even hundreds of operating parameters of the same category.

[0086] The collected operating parameters are compared with the respective threshold values ​​in the data storage and computing device 29. If an operating parameter of a category exceeds a corresponding threshold value for the predetermined period of time and for the predetermined quantity or number, a new control parameter is sent from the data storage and computing device 29 to all charging devices 22a, 22b, 22c.

[0087] The new control parameter is then sent from the charging device 22a, 22b, 22c to the respective connected accumulator 2a, 2b, 2c. It is also possible for the new control parameter to be stored in the charging device 22a, 22b, 22c and sent to different accumulators 2a, 2b, 2c that are subsequently connected to the charging device 22a, 22b, 22c.

[0088] In the control device of the accumulator 2a, 2b, 2c, the received new control parameter is used to replace a corresponding control parameter. This corresponding control parameter can also be referred to as the previous or old control parameter.

[0089] According to an alternative embodiment, it may also be possible for more than one new control parameter to be sent from the data storage and computing device 29 to the charging device 22a, 22b, 22c if more than one operating characteristic exceeds the corresponding threshold values. It is also possible for one or more new control parameters to be sent from the data storage and computing device 29 to the charging device 22a, 22b, 22c if one or more detected operating characteristic values ​​do not yet exceed the corresponding threshold values, but rather the detected operating characteristic values ​​merely correspond to these threshold values.

[0090] Furthermore, it is also possible that, instead of one or more new control parameters replacing the corresponding control parameters, a completely new set of control parameters is sent from the data storage and computing device 29 to the charging device 22a, 22b, 22c, and finally to the accumulator 2a, 2b, 2c. The completely new set of control parameters serves to replace the existing set of control parameters in the accumulator 2a, 2b, 2c.

[0091] When the charging device 22a, 22b, 22c has sent the new control parameter to the accumulator 2a, 2b, 2c and this new control parameter has replaced the previously existing corresponding control parameter, the actual charging process is started taking into account the new and the still existing control parameters.

[0092] If the comparison of a received operating characteristic with a corresponding threshold value reveals that the threshold has neither been exceeded nor reached, no new control parameter is sent from the data storage and computing device 29a to the charging device 22a, 22b, 22c and finally to the accumulator 2a, 2b, 2c. As a result, the charging process is started taking the existing control parameter into account.

[0093] List of reference symbols:

[0094] 1a first machine tool

[0095] 1 b second machine tool

[0096] 1c third machine tool

[0097] 2a first accumulator

[0098] 2b second accumulator

[0099] 2c third accumulator

[0100] 3 housings

[0101] 3a front end of the housing

[0102] 3b lower end of the housing

[0103] 4 housings

[0104] 4a first end of the housing

[0105] 4b second end of the housing

[0106] 5 Tool holder

[0107] 6 Drive

[0108] 7 Gear device

[0109] 8 Output shaft

[0110] 9 Control unit

[0111] 10 Machine tool storage unit

[0112] 11 T ransceiver of the machine tool

[0113] 12 Machine tool interface

[0114] 13a Positive contact of the machine tool interface

[0115] 13b Negative contact of the machine tool interface

[0116] 13c Communication contact of the machine tool interface

[0117] 14 operating switches

[0118] 15 battery housing

[0119] 15a Cover element of the battery housing

[0120] 15b Side panel of the battery housing

[0121] 15c Bottom element of the battery housing

[0122] 16 energy storage cells

[0123] 17 Battery interface

[0124] 18 Storage unit of the accumulator 19 Transceiver of the accumulator

[0125] 20 Accumulator control device

[0126] 22a first charging device

[0127] 22b second charging device

[0128] 22c third loading device

[0129] 23 charger housing

[0130] 23a Cover element of the charger housing

[0131] 23b Side walls of the charger housing

[0132] 23c Base element of the charger housing

[0133] 24 Charging device control unit

[0134] 25 Charging device transceiver

[0135] 26 Storage unit of the charging device

[0136] 27 Power supply of the charging device

[0137] 28 charger interface

[0138] 28a positive contact of the charger interface

[0139] 28b Negative contact of the charger interface

[0140] 28c Charger interface communication contact

[0141] 29 Data storage and computing device

[0142] 30 Sensor for detecting charging current and discharging current

[0143] 31 Sensor for recording a charging time

[0144] 32 Sensor for detecting an acceleration value and braking value

[0145] 33 Sensor for recording temperature values

[0146] 34 Sensor for measuring internal resistance values

[0147] 35 Sensor for detecting capacity

[0148] 36 counter

[0149] 37 Transceiver of the data storage and computing device

[0150] 38 Computing unit of the data storage and computing device

[0151] 39 Storage unit of the data storage and computing device

[0152] S System

Claims

Patent claims 1 . Method for controlling and regulating a system (S) containing at least a first accumulator (2a) with a first transceiver (19) and a first storage unit (18), a second accumulator (2b) with a second transceiver (19) and a second storage unit (18), a first charging device (22a) with a third transceiver (25) and a second charging device (22b) with a fourth transceiver (25), wherein each accumulator (2a, 2b) contains at least one sensor (30, 31, 32, 33, 34, 35) for detecting at least one parameter, characterized by the method steps - detecting at least one operating characteristic value by the at least one sensor (30, 31, 32, 33, 34, 35) of a respective accumulator (2a, 2b, 2c); - connecting the at least first accumulator (2a, 2b, 2c) to the first charging device (22a) and connecting the at least second accumulator (2a, 2b, 2c) to the second charging device (22b); - transmitting at least one operating characteristic value of the first accumulator (2a) detected by the sensor (30, 31, 32, 33, 34, 35) from the first accumulator (2a) to the first charging device (22a) before the start of a charging process, and transmitting at least one operating characteristic value of the second accumulator (2b) detected by the sensor (30, 31, 32, 33, 34, 35) from the second accumulator (2b) to the second charging device (22b) before the start of a charging process; - sending the at least one operating characteristic value of the first accumulator (2a) from the first charging device (22a) to a data storage and computing device (29) and sending the at least one operating characteristic value of the second accumulator (2b) from the second charging device (22b) to the data storage and computing device (29); - comparing the parameters of the first and second accumulators (2a, 2b) with threshold values ​​stored in the data storage and computing device (29); - comparing the respective operating characteristics with a threshold value stored in the data storage and computing device (29); - Sending at least one second control parameter from the data storage and computing device (29) via the charging device (22a, 22b) to the first and / or second accumulator (2a, 2b) to replace a first control parameter stored accordingly in the first and / or second accumulator (2a, 2b), if for a predetermined period of time and quantity at least one operating characteristic exceeds a threshold value stored in the data storage and computing device (29); and - Charging at least one accumulator (2a, 2b, 2c) with electrical energy by the charging device (22a, 22b, 22c) with at least the second control parameter.

2. Method according to claim 1, characterized by the method step - Sending at least one first control parameter of the accumulator (2a, 2b, 2c) from the accumulator (2a, 2b, 2c) to the charging device (22a, 22b, 22c) before starting a charging process.

3. Method according to claim 1 or 2, characterized by the method step - connecting the at least first or second accumulator (2a, 2b) to a machine tool (1a, 1b); - Supplying the machine tool (1a, 1b) with electrical energy by discharging at least the first or second accumulator (2a, 2b) with at least the second control parameter.

4. System (S) for carrying out the method according to at least one of claims 1 to 3, comprising at least a first and a second accumulator (2a, 2b), at least a first and a second charging device (22a, 22b) and at least a first and a second machine tool (1a, 1b), wherein the first and the second accumulator (2a, 2b) each contain a first transceiver (19) and a first storage unit (18), the first and the second charging device (22a, 22b) each contain a second transceiver (25) and a second storage unit (26), and the first and the second machine tool (1a, 1b) each contain a third transceiver (11) and a third storage unit (10).

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