Method for charging an energy supply device and system comprising an energy supply device and a charging device - Patents.com

Abstract

The invention relates to a method for charging a power supply device using a charging device, the power supply device having a set of energy storage cells and a control electronic system (CMS). The invention also relates to a system for performing the charging method, the system comprising a power supply device and a charging device. The control electronics of the power supply device are designed to monitor the current and / or the voltage of the power supply device and / or its energy storage cells and to communicate with the charging device. Within the context of the proposed charging method, an energy storage cell is selected and the transition from a first charging phase to a second charging phase of the charging process is initiated based on the voltage of the selected energy storage cell.

Description

[Technical field]

[0001] The invention relates to a method for charging an energy supply device via a charging device, the energy supply device having a string of energy storage cells and a control electronic unit (CMS). In a second aspect, the invention relates to a system for performing the charging method, the system comprising an energy supply device and a charging device. The control electronic unit of the energy supply device is configured to monitor the current and / or the voltage of the energy supply device and / or its energy storage cells and to communicate with the charging device. In the course of the proposed charging method, an energy storage cell is selected and the transition from the first charging phase to the second charging phase of the charging process is initiated based on the voltage of the selected energy storage cell. The charging process of the energy supply device is terminated by the control electronic unit of the energy supply device when a minimum current of one of the energy storage cells of the energy supply device is reached. [Background technology]

[0002] The present invention is in the technical field of rechargeable energy supply devices. In the prior art, charging methods for such rechargeable energy supply devices are known, but in many situations, using these methods, the energy supply devices cannot be charged in an optimal manner. In other words, an optimal improvement of the charging method can lead to a higher filling level.

[0003] When a new energy supply device is delivered, it can usually be charged with 100% full capacity. This refers to the 100% state of charge (SOC) of the energy supply device. However, over time, aging phenomena appear and the charging capacity of the energy supply device can decrease due to the energy supply device not being charged in an appropriate manner. This reduces the so-called state of health (SOH) of the energy supply device. The current state of health of the no longer new energy supply device can be determined, for example, by correlating the full capacity of the no longer new energy supply device with the full capacity of the new or delivered energy supply device.

[0004] In conventional charging methods as known from the prior art, the charging method can end undesirably even though not all of the energy storage cells of the energy supply device are yet fully charged. This can occur in particular when the charge states or charge histories of the energy storage cells of the energy supply device are uneven. Undesirable premature termination of the charging method often occurs when one of the cells has such a high voltage compared to the other cells of the energy supply device that further charging must be prevented. Such a situation can occur in particular with relatively old energy supply devices. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object of the present invention to overcome the above-mentioned drawbacks and disadvantages of the prior art and to provide an improved charging method and a corresponding system of an energy supply device and a charging device for carrying out said charging method. The aim of the present invention is to allow a higher filling level of the energy supply device after completion of the charging method than is currently possible in the prior art. [Means for solving the problem]

[0006] This object is achieved by the subject matter of the independent claims. Advantageous embodiments of the subject matter according to the invention are set forth in the dependent claims.

[0007] In a first aspect, the object is achieved by a method for charging an energy supply device via a charging device, the energy supply device having a bank of energy storage cells and a control electronic unit. The method comprises the following method steps: a) connecting an energy supply device to a charging device for charging the energy supply device; b) initiating a charging process in a first charging phase; c) determining, via a control electronic unit of the energy supply device, the selected energy storage cell based on the voltage of the energy storage cell; d) determining, via the control electronic unit, a charging current to the energy supply device based on the voltage of the preselected energy storage cell; e) transmitting a pre-determined charging current from the control electronic unit to the charging device; f) charging the energy supply device with a pre-determined charging current during a first charging phase; g) transitioning from the first charging phase to a second charging phase of the charging process when a maximum voltage of one of the energy storage cells is reached; It is characterized by:

[0008] In this case, the transition from the first charging phase to the second charging phase is initiated by a control command of the control electronic unit of the energy supply device to the charging device.

[0009] The proposed method allows charging the individual energy storage cells ("cells") of the energy supply device to a relatively high filling level. This allows the amount of energy transferred to the energy supply device by the charging process to be significantly increased, which advantageously increases the operating range of the energy supply device. The energy supply device can preferably be used in an electric tool to supply the electric tool with electric energy. If more energy is available in the energy supply device for each charging process, the period between the individual charging processes is advantageously longer, and work with the electric tool can be performed in a much more efficient and time-saving manner. The invention in particular allows charging the energy supply device at least to the maximum capacity of the weakest cell. In the context of the invention, the energy storage cell that has the lowest, i.e. the smallest, voltage at the start of the first charging phase of the charging process is preferably considered to be the "weakest energy storage cell". As a result, a higher filling level of the energy supply device is advantageously reached than with conventional charging methods.

[0010] In the context of the present invention, it is preferable to consider the energy storage cell with the lowest voltage in the first charging phase of the charging method. If an energy storage cell is very deeply discharged, it can preferably be charged with a reduced current. The weakest energy storage cell can be, for example, the energy storage cell that can store or take up the smallest amount of charge.

[0011] It has been shown that the transition from the first charging phase to the second charging phase can be performed particularly simply if the control electronic unit of the energy supply device sends a control command for the switchover to the charging device. As a result, the energy supply device can advantageously take over the control of the charging device and the charging process. Furthermore, the charging device therefore does not need to know the individual voltages and / or thresholds of the individual energy storage cells of the energy supply device. The voltages of the energy storage cells of the energy supply device are preferably ascertained independently of the proposed method, such that they are already available in the energy supply device. In the context of the present invention, the energy supply device can decide to keep the charging voltage at the energy storage cells substantially constant from the determined threshold value. The second charging phase preferably starts in this way with the charging voltage being kept constant. The present invention is associated with the advantage that different types of energy supply devices can be charged using the charging device. In this case, it is possible to switch between the individual phases of the charging process individually for the different types of energy supply devices, i.e. depending on the ascertained voltages of the energy storage cells in the respective energy supply device. As a result, different threshold values ​​can be implemented for the individual cell voltages depending on the cell type. The control electronic unit of the energy supply device can be formed by a so-called cell management system (CMS). The control electronic unit is part of the energy supply device and has various functions. By way of example, the control electronic unit of the energy supply device is configured to monitor the current and / or voltage of the energy supply device and / or its energy storage cells. To this end, the control electronic unit of the energy supply device can have corresponding sensors or measuring points which detect the current and / or voltage of the individual cells or of the entire energy supply device. This detection can be performed substantially continuously or at a determined, for example predetermined, measurement frequency. The detected current and / or voltage data can be recorded and / or stored, the energy supply device preferably having a data memory for this purpose.The detected current and / or voltage data can in particular be used to determine the weakest energy storage cell of the energy supply device based on the voltage of the energy storage cell. In other words, the control electronic unit of the energy supply device is capable of determining the weakest energy storage cell of the energy supply device based on the voltage of the energy storage cell. In the context of the present invention, it is very particularly preferred that the control electronic unit of the energy supply device defines as the "weakest cell" in a first charging phase of the charging process the cell which has the lowest voltage at the start of the first charging phase.

[0012] In the context of the present invention, an empty energy storage cell is preferably characterized by a low voltage, whereas a fully charged energy storage cell is characterized by a high voltage. In the context of the present invention, it is preferable to monitor the voltage of the individual cells at regular intervals, a typical interrogation interval being, for example, 100 milliseconds (ms). This regular monitoring has been found to be particularly advantageous, especially when the voltage of an energy storage cell is at the lower and / or upper end of a tolerance range.

[0013] The invention is based on the basic idea of ​​adapting the charging method to the demands and requirements of the weakest energy storage cell of the energy supply device. This weakest energy storage cell is determined in the course of the proposed method. The inventors have therefore realized that when charging the energy supply device, a higher filling level can be reached than in the case of conventional charging methods as known from the prior art. Depending on the charging phase of the charging process, different energy storage cells of the energy supply device can be determined to be the "weakest cell", this determination being carried out on the basis of the voltage of the energy storage cell. In the context of the invention, it may also be preferred that in the case of equal voltage ratios in the energy supply device, one and the same cell is considered to be the weakest cell in both charging phases. In this case, that one cell has the lowest voltage of the cells at the start of the first charging phase of the charging process and the highest voltage of the energy storage cells of the energy supply device at the start of the second charging phase.

[0014] If, when monitoring the voltages of the energy storage cells of the energy supply device, a cell is noticeable that has a different voltage compared to the other cells, the control electronic unit of the energy supply device will therefore consider this cell as the "weakest cell" in the context of the present invention. The cell that has the lowest voltage and therefore the lowest fill level at the beginning of the first charging phase of the charging process can be considered as the "weakest cell" in the context of the present invention. In the context of the present invention, it is preferred that the cell with the lowest state of health (SOH) has the lowest voltage among the energy storage cells of the energy supply device at the end of its discharge. During the charging process, this "weakest cell" is preferably characterized by having the largest voltage rise. In the context of the present invention, it is also preferred that this "weakest cell" has the highest voltage among the energy storage cells of the energy supply device at the end of the charging process.

[0015] In addition, the control electronic unit of the energy supply device can communicate with the charging device. Preferably, there may be a communication connection between the energy supply device and the charging device, through which current data, voltage data and / or control commands can be exchanged between the energy supply device and the charging device. The communication connection may be wired or wireless, but in the context of the present invention, wired communication between the energy supply device and the charging device is preferred. As an example, the control electronic unit of the energy supply device can send an inquiry to the charging device to find out the current value of the energy supply device. As an example, the control electronic unit of the energy supply device can inquire about the total current flowing from the charging device to the energy supply device during the charging process. In the context of the present invention, in the case of parallel-connected cells, it is preferred that this total current is divided over the individual lines of the energy supply device.

[0016] In an alternative configuration of the invention, the control electronic unit of the energy supply device can ascertain the current value of the energy supply device using its own measurements.

[0017] The content of the control command exchanged between the energy supply device and the charging device may be, for example, that the control electronic unit of the energy supply device instructs the charging device to terminate the charging process. This control command from the control electronic unit of the energy supply device to the charging device is sent in particular when a minimum current of one of the energy storage cells of the energy supply device is reached. However, in the context of the present invention, it may also be preferred that only the total current introduced above is measured and transmitted. In addition, a control command is transmitted from the control electronic unit of the energy supply device to the charging device when the charging process should transition from the first charging phase to the second charging phase. In other words, the control electronic unit of the energy supply device is configured to perform the transition from the first charging phase to the second charging phase of the charging process when the maximum voltage of the weakest energy storage cell is reached. The first charging phase of the charging process is preferably characterized by a substantially constant charging current, while in the second charging phase of the charging process the charging voltage is substantially constant. The expression "substantially constant" does not represent an unclear expression for a person skilled in the art. Because the skilled person knows that this expression is intended to include not only mathematically exactly equal current or voltage values, but also slight deviations or variations, for example in the range of + / - 5%. In the context of the present invention, it is preferred that the charging voltage corresponds to the maximum voltage of the weakest energy storage cell.

[0018] In the first charging phase, the energy supplying device or its control electronic unit preferably prescribes a charging current according to a selected or weakest energy storage cell or its voltage in a manner optimized for this selected and / or weakest energy storage cell of the energy supplying device. In this context, the charging current to the energy supplying device can be ascertained based on the voltage of the weakest energy storage cell, this ascertainment of the charging current being performed by the control electronic unit of the energy supplying device.

[0019] In particular, the charging current is ascertained on the basis of the voltages of the energy storage cells of the energy supply device. In this case, the lowest cell voltage, i.e. the voltage of the "weakest cell", preferably determines the charging current with which the energy supply device is charged or can be charged so as not to damage the energy storage cells. In particular, if individual cells are very deeply discharged, it is preferred in the context of the present invention that these cells receive a particularly gentle initial charge. On the basis of the voltages of the energy storage cells detected using the control electronic unit of the energy supply device, a corresponding charging current can be requested from the charging device. The charging device is preferably configured to set and provide the charging current required by the energy supply device.

[0020] The charging current ascertained by the control electronic unit of the energy supply device can then be transmitted to the charging device. In the context of the present invention, it is very particularly preferred that the charging current is kept substantially constant in the first charging phase of the charging process, the charging current preferably corresponding to the maximum current value of the weakest cell.

[0021] When the voltage maximum value of the first cell of the energy supply device is reached, the charging phase changes or the charging process transitions from the first charging phase to the second charging phase. In the context of the present invention, this transition from the first charging phase to the second charging phase can also be preferably called switching. In the second charging phase, the voltage is preferably kept substantially constant. In the context of the present invention, the energy storage cells of the energy supply device are preferably connected in series (series connection) such that the voltages of the energy storage cells are preferably summed. The voltage of the cells can preferably be kept constant by maintaining the total voltage value at which the first cell of the energy supply device reaches its voltage maximum. In the context of the present invention, when the total voltage of the energy supply device remains substantially constant, the voltage of the individual energy storage cells preferably does not change substantially anymore.

[0022] In the context of the present invention, the energy storage cell with the highest voltage is preferably considered as the weakest energy storage cell in the second charging phase of the charging process. This may be the same cell that was also considered as the weakest cell in the first charging phase of the charging process. In the context of the present invention, the cell capable of storing the least energy is preferably the first cell that becomes substantially empty during discharging, an empty cell preferably having a very low voltage. During charging, this cell is preferably the first cell to reach a "full" fill level or state of charge. As a result, it preferably has a higher voltage than the other cells. The switchover to the second charging phase can preferably be achieved by keeping the voltage of the charging device substantially constant from the transition from the first charging phase to the second charging phase. This can be communicated by the energy supply device to the charging device, for example, through a communication connection. The switchover point between the first and second charging phases of the charging process can preferably be n times the maximum cell voltage, where "n" is the number of energy storage cells in the energy supply device. This value preferably corresponds to a measurement of the sum of all individual cell voltages. The switching point between the first and second charging phases of the charging process can preferably be selected to be a measurement of the total voltage at the connection of the energy supply device. The measurement time is preferably the time at which the energy storage cell with the highest voltage reaches its designated charging voltage. In the second charging phase, the energy supply device is preferably charged in a voltage regulation mode. If the cell voltages differ significantly, it may be preferable in the context of the present invention for the transition between the first and second charging phases of the charging process, i.e. the switching between the different regulation modes, to take place earlier.

[0023] The control electronic unit of the energy supply device sends a control command to the charging device when a voltage maximum value is reached for the first cell of the energy supply device, so that the charging device adjusts, regulates or sets the current and / or voltage accordingly. In the context of the present invention, it is preferred that the transition from the first charging phase to the second charging phase is initiated by a control command of the control electronic unit of the energy supply device to the charging device. The control electronic unit of the energy supply device sends a control command to the charging device, in particular for adjusting the charging current, and during the transition from the first charging phase to the second charging phase of the charging process there is a switchover from a charging phase with a substantially constant charging current to a charging phase with a substantially constant charging voltage.

[0024] In the context of the present invention, the charging process is preferably terminated when a minimum current of one of the energy storage cells of the energy supply device is reached. The charging process can be terminated by the control electronic unit of the energy supply device, in particular when the total charging current of the energy supply device is reached. The control electronic unit of the energy supply device then transmits a corresponding control command to the charging device. The energy supply device can then be removed or disconnected from the charging device and can be connected to the power tool, for example, to supply electrical energy to the power tool during operation of the power tool.

[0025] In the context of the present invention, it is preferred that the voltage of the energy storage cell and / or the energy supply device is monitored by a control electronic unit of the energy supply device, which preferably makes it possible to determine when the maximum voltage of the energy storage cell has been reached.

[0026] In the context of the present invention, the energy supplying device is preferably charged in a first charging phase with a first substantially constant partial charging current and with a second substantially constant partial charging current. In other words, the first charging phase can be divided, for example, into two partial charging phases, each partial charging phase being characterized by a separate partial charging current. The second partial charging current can preferably be higher or greater than the first partial charging current. The first partial charging phase using the lower first partial charging current can preferably be referred to as an initial charging, while the energy supplying device can be subsequently further charged in a second partial charging phase with the second partial charging current.

[0027] In addition, the value of the constant charging current in the first charging phase may be adjusted based on temperature changes, preferably in a stepwise manner, with the value of the charging current generally remaining constant for a relatively long time following the change.

[0028] Current and / or voltage data can preferably be exchanged between the energy supply device and the charging device, and absolute and / or relative current and / or voltage values ​​can be exchanged between the energy supply device and the charging device in the course of the proposed charging method. In the context of the present invention, this preferably means that absolute current values, such as 1 Ampere (A), 4.05 A or 2.33 A, and / or absolute voltage values, such as 1 Volt (V), 4.05 V or 2.33 V, can be transmitted from the energy supply device to the charging device. Alternatively or additionally, however, it is also possible to exchange relative current and / or voltage values ​​between the energy supply device and the charging device. In the context of the present invention, this preferably means that the current and / or voltage values ​​are indicated in relation to a reference value, for example a nominal voltage or a predefined current value. The relative current and / or voltage values ​​can, for example, be indicated as a percentage (%) or a proportion.

[0029] In the context of the present invention, it is preferred that the temperature of the energy supply device is also monitored by the control electronic unit of the energy supply device.

[0030] The control electronic unit of the energy supply device is therefore configured to monitor, in addition to the current and voltage of the energy supply device or its energy storage cells, also the temperature of the energy supply device or its energy storage cells, which makes it possible to ensure that the temperature of the energy supply device is within a range provided for this purpose, so that overheating of the energy supply device or thermal damage thereto is effectively avoided.

[0031] In a second aspect, the invention relates to a system comprising an energy supply device and a charging device for charging the energy supply device, the energy supply device having a string of energy storage cells and a control electronic unit. The system is characterized in that the control electronic unit of the energy supply device is configured to monitor the current and / or the voltage of the energy supply device and / or its energy storage cells and to communicate with the charging device in the sense that current data, voltage data and / or control commands are exchanged between the energy supply device and the charging device. In addition, the control electronic unit of the energy supply device is configured to determine selected energy storage cells of the energy supply device based on the voltages of the energy storage cells and to perform a transition from a first charging phase to a second charging phase of the charging process when a maximum voltage of one of the energy storage cells is reached. The control electronic unit is configured to check a charging current to the energy supply device based on the voltages of preselected energy storage cells and to transmit the thus checked charging current to the charging device, the energy supply device being charged with the prechecked charging current in the first charging phase, the control electronic unit of the energy supply device being further configured to transmit a control command for the transition from the first charging phase to the charging device. The definitions, technical effects and advantages explained with respect to the proposed charging method apply equally to a system consisting of an energy supply device and a charging device. In particular, the system is configured to perform the above-mentioned charging method. The system can therefore be called "a system for performing the proposed charging method". In the context of the present invention, determining a selected energy storage cell based on the voltages of different energy storage cells in the energy supply device is preferably also called "selecting an energy storage cell".

[0032] In the context of the present invention, the energy storage cell with the lowest voltage at the beginning of the first charging phase of the charging process is preferably considered to be the weakest energy storage cell, while in the second charging phase the energy storage cell with the highest voltage is called the weakest cell. In addition, the control electronic unit of the energy supply device is configured to terminate the charging process of the energy supply device when a minimum current of one of the energy storage cells of the energy supply device is reached. The energy supply device and the charging device can exchange current data, voltage data and / or control commands, the control commands being transmitted in particular from the control electronic unit of the energy supply device to the charging device. As an example, the control electronic unit of the energy supply device transmits a control command for the transition from the first charging phase to the second charging phase to the charging device. The control electronic unit of the energy supply device can also be configured to monitor the temperature of the energy supply device in order to ensure that the cells of the energy supply device are always within their permissible temperature range. To detect the temperature, the energy supply device can be equipped with a suitable sensor and an evaluation unit. The energy supply device can preferably interrupt the charging process if the energy supply device detects that one of the cells or the entire energy supply device has a temperature outside the permissible temperature range. To this end, the control electronic unit of the energy supply device can send corresponding control commands to the charging device. In the context of the present invention, it is preferred that the charging current is substantially constant in a first charging phase of the charging process and that the charging voltage is substantially constant in a second charging phase of the charging process.

[0033] Further advantages will become apparent from the following description of the figures. Exemplary embodiments of the invention are illustrated in the figures. Numerous feature combinations are included in the figures, the specification and claims. Those skilled in the art will also consider features individually and combine them as appropriate to generate further useful combinations.

[0034] In the figures, identical and similar components are designated with the same reference numerals. [Brief description of the drawings]

[0035] [Figure 1] FIG. 2 shows a schematic diagram of a power tool with a preferred configuration of the energy supply device of the present system. [Diagram 2] 1 shows a schematic diagram of a preferred configuration of the present system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] FIG. 1 shows a schematic diagram of a power tool 30 with an energy supply device 10. The power tool 30 can be, for example, a cut-off grinder with a cut-off wheel as a tool. The power tool 30 can have, for example, a grip designed as a rear handle. In addition, the power tool 30 can have operating elements such as switches or buttons in a manner known per se. Furthermore, the power tool 30 can have a motor (not shown) which can represent a load and can be supplied with electrical energy by the energy supply device 10. The energy supply device 10 depicted in FIG. 1 has two energy storage cells 12 in the illustrated schematic exemplary embodiment. In addition, the energy supply device 10 shown in FIG. 1 comprises a control electronic unit 14.

[0037] Fig. 2 shows a schematic diagram of a preferred configuration of the proposed system 100 consisting of an energy supply device 10 and a charging device 20. The energy supply device 10 can be connected to the charging device 20 for charging. To this end, interfaces 16, 22 can be provided, and the energy supply device 10 and the charging device 20 can be connected to each other through the respective interface partners 16, 22. In the exemplary embodiment shown in Fig. 2, the energy supply device 10 has two energy storage cells 12, one of which represents the weakest energy storage cell 18 of the energy supply device 10. The energy supply device 10 can of course comprise more than two energy storage cells 12, for example 5, 6, 8, 10, 12 or 18 energy storage cells 12. In addition, the energy supply device 10 has a control electronic unit 14. The energy supply device 10 can communicate with the charging device 20 through a communication connection 40, i.e. exchange current data, voltage data and / or control commands. To this end, the energy supplying device 10 and the charging device 20 can have a communication module 42, 44. The communication module 42 of the energy supplying device 10 can be - as shown in Fig. 2 - part of the energy supplying device 10. However, in the context of the present invention it can also be preferred that the communication module 42 of the energy supplying device 10 is part of the control electronic unit 14 of the energy supplying device 10. [Explanation of symbols]

[0038] 10 Energy supply device 12 Energy Storage Cell 14 Control Electronic Unit 16 Energy Supply Device Interface 18 Weakest Energy Storage Cell 20 Charging device 22 Charging device interface 30 Power tools 40 Communication connection between the energy supply device and the charging device 42 Communication module of energy supply device 44 Charging device communication module 100 Systems

Claims

1. A method for charging an energy supply device (10) via a charging device (20), said energy supply device (10) having an array of energy storage cells (12) and a control electronic unit (14), The method comprises the following steps: a) connecting the energy supply device (10) to the charging device (20) for charging the energy supply device (10); b) initiating a charging process in a first charging phase; c) determining, via the control electronic unit (14) of the energy supply device (10), a selected energy storage cell (18) based on the voltage of the energy storage cell (12); d) determining, via the control electronic unit (14), a charging current to the energy supply device (10) based on the voltage of the preselected energy storage cell (18); e) transmitting the pre-determined charging current from the control electronic unit (14) to the charging device (20); f) charging the energy supply device (10) with the pre-determined charging current during the first charging phase; g) transitioning from the first charging phase to a second charging phase of the charging process when a maximum voltage of the energy storage cell (12) is reached; having the transition from the first charging phase to the second charging phase is initiated by a control command of the control electronic unit (14) of the energy supply device (10) to the charging device (20), Characterized in that method.

2. The charging process is terminated when a minimum current is reached in one of the energy storage cells (12) of the energy supply device (10). Characterized in that The method of claim 1.

3. The voltage and / or current of the energy storage cell (12) and / or the energy supply device (10) are monitored by the control electronic unit (14) of the energy supply device (10). Characterized in that The method according to claim 1 or 2.

4. Current and / or voltage data is exchanged between the energy supply device (10) and the charging device (20). Characterized in that The method according to any one of claims 1 to 3.

5. The charging current is substantially constant during the first charging phase of the charging process, and the charging voltage is substantially constant during the second charging phase of the charging process. Characterized in that The method according to any one of claims 1 to 4.

6. During the course of the method, absolute and / or relative current and / or voltage values ​​are exchanged between the energy supply device (10) and the charging device (20). Characterized in that The method according to any one of claims 1 to 5.

7. The temperature of the energy supply device (10) is also monitored by the control electronic unit (14) of the energy supply device (10). Characterized in that The method according to any one of claims 1 to 6.

8. A system (100) comprising an energy supply device (10) and a charging device (20) for charging said energy supply device (10), said energy supply device (10) having an array of energy storage cells (12) and a control electronic unit (14), The control electronic unit (14) of the energy supply device (10) is configured to monitor the current and / or voltage of the energy supply device (10) and / or the energy storage cells (12) of the energy supply device (10) and to communicate with the charging device (20) in the sense that current data, voltage data and / or control commands are exchanged between the energy supply device (10) and the charging device (20), and the control electronic unit (14) of the energy supply device (10) determines a selected energy storage cell (18) of the energy supply device (10) based on the voltage of the energy storage cells (12) and determines when a maximum voltage of one of the energy storage cells (12) has been reached. and performing a transition from a first charging phase to a second charging phase of the charging process when the energy storage cell is charged, the control electronic unit (14) being configured to determine the charging current to the energy supply device (10) based on the voltage of the preselected energy storage cell (18) and to transmit the thus determined charging current to the charging device (20), the energy supply device (10) being charged with the pre-determined charging current during the first charging phase, and the control electronic unit (14) of the energy supply device (10) being configured to transmit a control command to the charging device (20) for the transition from the first charging phase to the second charging phase. Characterized in that System (100).

9. At the start of the first charging phase, the energy storage cell (12) with the lowest voltage is considered to be the weakest energy storage cell (18), and at the start of the second charging phase, the energy storage cell (12) with the highest voltage is considered to be the weakest energy storage cell (18). Characterized in that The system (100) of claim 8.

10. The control electronic unit (14) of the energy supply device (10) is configured to terminate the charging process of the energy supply device (10) when a minimum current of one of the energy storage cells (12) of the energy supply device (10) is reached. Characterized in that 10. The system (100) according to claim 8 or 9.

11. The energy supply device (10) and the charging device (20) are configured to exchange current and / or voltage data. Characterized in that A system (100) according to any one of claims 8 to 10.

12. The control electronic unit (14) of the energy supply device (10) is configured to monitor the temperature of the energy supply device (10). Characterized in that A system (100) according to any one of claims 8 to 11.

13. The charging current is substantially constant during the first charging phase of the charging process, and the charging voltage is substantially constant during the second charging phase of the charging process. Characterized in that A system (100) according to any one of claims 8 to 12.

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