Electrical energy storage device, electrical battery charger and method for charging an electrical energy storage device

Abstract

In an electrical energy storage device (1; 101) having a plurality of battery units (2; 102) which are connected in parallel with one another and each contain a rechargeable battery for storing energy and a battery control unit (4; 104) for controlling the intake and delivery of energy by the battery unit (2; 102), each battery control unit (2; 102) contains a two-port network having a two-pole input port (7; 107) and a two-pole output port (8; 108), and the two-port networks are connected by means of connection of the output port (8; 108) of one two-port network to the input port (7; 107) of an adjacent two-port network to form a chain such that a circuit leading through all the two-port networks can be produced by connecting a voltage or current source to the input port (7; 107) of the first two-port network and short-circuiting the output port (8; 108) of the last two-port network in the chain. Each two-port network has a switch (9; 109) which can be actuated by the battery control unit (4; 104) and by means of which the current flowing at the input port (7; 107) can be changed.

Description

[0001] Electrical energy storage device, electrical battery charger and method for charging an electrical energy storage device

[0002] The invention relates to an electrical energy storage device according to the preamble of claim 1, an electrical battery charger according to the preamble of claim 9 and a method for charging an electrical energy storage device according to the preamble of claim 13.

[0003] Electrically powered vehicles are supplied with power using, among other things, electrical energy storage devices consisting of a large number of interconnected battery units. Each battery unit contains not only a battery suitable for receiving and releasing electrical energy, but also a battery control unit, also called a battery management system (BMS). This BMS controls and monitors the operation of the battery unit and can interrupt charging and discharging if necessary to prevent overcharging or excessive discharging. The BMS is also responsible for limiting the charging and discharging current to a maximum permissible value and for terminating charging or discharging in the event of a fault.

[0004] To initiate or terminate the charging process, the battery control units of an electrical energy storage device and the charging control unit of a battery charger must communicate with each other. A fieldbus system is a suitable option for this, but this solution requires that both the energy storage device and the battery charger be equipped with the same fieldbus system. This entails corresponding costs and limits the possible combinations of energy storage devices and battery chargers.

[0005] From US patent 2017 / 0040796 A1, a communication system in an electrical installation with a large number of parallel-connected batteries is known, in which an energy management system is assigned to each load connected to the batteries, and each battery is equipped with a battery management system. To enable communication between the energy management system and the battery management systems, both are connected to the lines that connect the load to the batteries for power transmission. Binary data in the form of an alternating voltage is transmitted over these lines, superimposed on the existing direct voltage between the lines. This eliminates the need for additional signal lines or a wireless connection between the energy management system and the battery management systems. The CAN bus protocol is used as the communication protocol for data transmission.

[0006] From DE 102018108041 A1, a charging method for several parallel-connected battery blocks is known, in which each battery block has a control unit, a monitoring unit, and a switching device for disconnecting or connecting the battery block to or from the charger and the other battery blocks. Depending on at least one operating parameter of a battery block detected by the monitoring unit, it is disconnected or connected for a portion of the charging time by means of the switching device. Communication between the control unit, the monitoring unit, and the switching device of each battery block, as well as communication between the control units and a higher-level master control unit, takes place via a CAN bus.

[0007] The invention is based on the objective of creating a simple solution for communication between an energy storage device and a battery charger, which enables the initiation and termination of a charging process without the use of a fieldbus system.

[0008] This problem is solved according to the invention by an electrical energy storage device with the features of claim 1, an electrical battery charger with the features of claim 9, and by a method for charging an electrical energy storage device with the features of claim 13. Advantageous embodiments of the invention are specified in the respective dependent claims.

[0009] In an electrical energy storage device according to the invention with a plurality of battery units connected in parallel to one another, each containing a rechargeable battery for storing energy and a battery control unit for controlling the absorption and release of energy by the battery unit via a power circuit, each battery control unit contains a two-port with a two-pole input port and a two-pole output port, and the two-ports are connected to form a chain by connecting the output port of one two-port to the input port of an adjacent two-port such that by connecting a voltage or current source to the input port of the first two-port and short-circuiting the output port of the last two-port in the chain, a control circuit leading through all two-ports, separate from the power circuit, can be established.Furthermore, each two-gate has a switch that can be operated by the battery control unit, through which the current flowing at the entrance gate can be changed.

[0010] With this circuit configuration, the input gate of the first two-port of the chain forms a two-pole control interface for connection to a charging control unit of an electric battery charger, via which the charging readiness of the battery units can be signaled in a simple way and a charging process can be initiated and stopped without the need for a complex digital communication channel in the form of a fieldbus system between the energy storage device and the battery charger.

[0011] A preferred method for signaling charging readiness is to have the switch of a two-port gate closed when the battery unit is ready for charging and open when the battery unit is not ready for charging. This ensures that a break in the circuit cannot falsely signal charging readiness.

[0012] Preferably, each two-port interface has a current measuring unit for the current flowing at the input port and / or a voltage measuring unit for the voltage present at the input port. This allows a battery control unit to determine whether a connected battery charger is also ready for charging; that is, signaling in the other direction is also possible.

[0013] A suitable circuit configuration consists of the switch being connected between one terminal of the input port and one terminal of the output port of the second port of a battery control unit, the other terminals of the input port and output port of the second port of each battery control unit being directly connected, and the output port of the last second port in the chain being short-circuited. In this case, the circuit runs through all battery control units in such a way that each battery control unit must signal the readiness of its respective battery unit to be charged by closing its respective switch in order for charging to begin, and the charging process can be interrupted by each individual battery control unit by opening its switch when its battery unit is no longer capable of being charged.

[0014] Another convenient circuit configuration involves connecting a voltage measuring unit in parallel to the input port of the two-port in a battery control unit, or between a terminal of the input port connected to the switch and the negative terminal of the battery unit, and short-circuiting the output port of the last two-port in the chain. This allows for alternative signaling of the charging readiness of a battery charger to a battery control unit of the energy storage device using a voltage instead of a current.

[0015] Preferably, in each two-port network, a switch and a power source are connected in series between the terminals of the output port, one terminal of the input port and one terminal of the output port are directly connected to each other, and the other terminal of the output port is connected to the other terminal of the input port in such a way that a control circuit separate from the power circuit can be established by connecting a resistor to the input port. This enables active signaling of the charging readiness of a battery unit by means of a current output from the battery control unit.

[0016] In the latter circuit configuration, it is advantageous to connect a current measuring unit between the other terminal of the input gate and the series connection of the switch and the power source. This allows for the determination of the charging readiness of a connected battery charger, i.e., signaling in the other direction as well.

[0017] Preferably, the battery control units are interconnected via a fieldbus. This enables enhanced communication between the battery control units. In particular, if a battery charger signals its charging readiness by means of a voltage applied by its charging control unit to the input gate of the first two-port of the cascade circuit, the charging readiness of the battery charger can be relayed to all other battery control units via such a fieldbus.

[0018] According to the invention, an electric battery charger with a charging interface for supplying charging current to a rechargeable battery and with a charging control unit is provided that the charging control unit, for communication with battery control units of battery units of an electric energy storage device, has a two-pole control interface separate from the charging interface and a current measuring unit for a current flowing via the control interface and / or a voltage measuring unit for a voltage applied to the control interface. This makes the battery charger according to the invention suitable for charging an energy storage device according to the invention.For this purpose, the first input port of the cascade of two-port battery control units can be connected to the aforementioned control interface of the charging control unit. This enables communication between the charging control unit and the battery control units to initiate and terminate a charging process via the resulting control circuit. The battery charger can easily detect the charging readiness of connected battery units.

[0019] Analogous to the energy storage system according to the invention, it is also advantageous in the battery charger according to the invention that the charging control unit has a switch that it can actuate, by which a current flowing via the control interface and / or a voltage applied to the control interface can be changed, the current is switched on by the switch when the battery charger is ready to charge, and off when the battery charger is not ready to charge. This allows the battery charger to signal its own readiness to charge to connected battery units.

[0020] A suitable configuration involves the charging control unit having a voltage or current source that can be switched on via a switch at the control interface to supply voltage and / or current. In this case, a circuit for communication between the charging control unit and connected battery control units can be passively opened and closed by the battery control units themselves, i.e., via their switches. Alternatively, the charging control unit can have an electrical resistor that can be switched on via a switch at the control interface. This requires the presence of current or voltage sources in the battery control units to form a circuit through the charging control unit and connected battery control units.

[0021] An inventive method for charging an inventive electrical energy storage device by means of an inventive electrical battery charger comprises the following steps: establishing a control circuit, separate from the charging circuit, which runs through the charging control unit of the battery charger and the battery control unit of at least one battery unit of the energy storage device ready for charging, by closing switches in the charging control unit and in the battery control unit of the battery unit ready for charging; detecting the closed state of the established control circuit by measuring the current flowing in it by a current measuring unit or a voltage caused by the current by a voltage measuring unit in the charging control unit; and supplying a charging current by the battery charger to the battery units if and as long as the current measuring unit or voltage measuring unit detects a current flowing in the battery unit.The voltage measuring unit of the charging control unit detects the flow of current in the control circuit. This method allows the charging of battery units of an energy storage device according to the invention to be initiated and terminated easily by a battery charger according to the invention.

[0022] It is advantageous for the battery control unit of a battery unit to interrupt the part of the control circuit running through it when the battery unit is no longer ready to charge, and / or for the charging control unit (5; 105) to interrupt the part of the control circuit running through it when the battery charger (3; 103) is no longer ready to charge. In this way, a loss of charging readiness of a battery unit and / or the battery charger can be reliably signaled to the control unit of the other system component.

[0023] Preferably, the battery control unit of a battery unit ready for charging feeds current into the control circuit via its own power source when the circuit is closed, and the charging control unit adjusts the charging current it delivers to the battery units depending on the value of the current in the control circuit measured by its current measuring unit. This allows the charging current delivered by the battery charger to be precisely adjusted to the charging current requirements of the battery units.

[0024] Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. These show

[0025] Fig. 1 shows a first embodiment of an energy storage device according to the invention and an associated battery charger.

[0026] Fig. 2 shows a second embodiment of an energy storage device according to the invention and an associated battery charger.

[0027] Fig. 3 shows a third embodiment of an energy storage device according to the invention and an associated battery charger,

[0028] Fig. 4 shows a fourth embodiment of an energy storage device according to the invention,

[0029] Fig. 5 shows a fifth embodiment of an energy storage device according to the invention and an associated battery charger,

[0030] Fig. 6 shows a first embodiment of a method according to the invention in the form of a flowchart,

[0031] Fig. 7 shows a second embodiment of a method according to the invention in the form of a flowchart,

[0032] Fig. 8 shows a third embodiment of a method according to the invention in the form of a flowchart. Fig. 1 shows an electrical energy storage device 1 according to the invention, which consists of a plurality of identical battery units 2 and is connected to a battery charger 3 according to the invention for charging. For charging, the battery units 2 are connected in parallel to each other. In this as well as in all other embodiments, three battery units 2 are shown, but there could also be fewer or more than three. Each battery unit 2 contains a battery control unit 4, also called a battery management system, and the battery charger 3 contains a charging control unit 5. The battery control units 4 are connected to each other via a fieldbus 6 for communication. Since all battery control units 4 are identical, in Fig.

[0033] 1. Only the components of a battery control unit are provided with reference numbers. This also applies to the other embodiments.

[0034] For easy communication with the charging control unit 5 to initiate and terminate the charging process, the battery control units 4 each contain a two-port interface with an input port 7 and an output port 8. These two-port interfaces are connected in a chain by connecting the output port 8 of one two-port interface to the input port 7 of the next two-port interface in the chain. The input port 7 of the first two-port interface in the chain provides an interface for connection to the charging control unit 5 of the battery charger 3. The output port of the last two-port interface is short-circuited. In each two-port interface, a switch 9 and a current measuring unit 10 are connected in series between one terminal of the input port 7 and one terminal of the output port 8, and the other terminals of the input port 7 and the output port 8 are directly connected to each other.Due to the cascaded connection, the switches 9 and current measuring units 10 of all two-ports are connected in series and, via the short circuit at the output port 8 of the last two-port and the direct connections within the two-ports, are connected to the other terminal of the input port 7 of the first two-port. Thus, when the switches 9 of all two-ports are closed, a current path runs through all switches 9 and current measuring units 10, through which a current flows as soon as a voltage is applied to the input port 7 of the first two-port. This current path constitutes a separate control circuit from the power circuit, through which the battery of the battery unit is charged or discharged as needed.

[0035] A voltage can be applied to the input port 7 of the first two-port by the charging control unit 5 of the battery charger 3 at its two-pole control interface 11 by closing an internal switch 12. This switch, via a resistor 13, establishes a connection between a first terminal of the control interface 11 and a terminal of a voltage source, at which the voltage source outputs a voltage VI relative to ground 14 of the charging control unit 5. Switch 12 and switch 9 can consist of components such as transistors, optocouplers, or relays and are controlled by a microcontroller. The second terminal of the control interface 11 is connected to ground 14. A current measuring unit 15 is connected between switch 12 and the first terminal of the control interface 11.Alternatively or additionally, a voltage measuring unit 16 can be connected between the terminal of switch 12 connected to resistor 13 and ground. This unit can detect the flow of current when switch 12 and all switches 9 are closed by measuring the voltage drop from the source voltage VI to a significantly lower value. As shown in Fig. 1, to charge the energy storage unit, not only are the terminals of the individual battery units 2 connected to the charging terminals of the battery charger, but the input port 7 of the first two-port of the cascade circuit is also connected to the control interface e 11 of the charging control unit 5.

[0036] A second embodiment of an energy storage device 1 according to the invention, in combination with the same battery charger 5 as shown in Fig. 1 in combination with the first embodiment, is shown in Fig. 2. The only difference between the second and the first embodiment is that, in the second embodiment, instead of a current measuring unit 10 in series with the switch 9, a voltage measuring unit 17 is connected in parallel to the input port 7 of each two-port of the chain. All other components of the battery control unit 4 and the charging control unit 5 are identical to those of the first embodiment, which is why they are not labeled with reference numerals in Fig. 2 and are not described again here.

[0037] A third embodiment of an energy storage device 1 according to the invention, in combination with the same battery charger 5 as shown in Figures 1 and 2 in combination with the first and second embodiments, respectively, is shown in Figure 3. In contrast to the second embodiment, in the third embodiment, instead of the current measuring unit 10 being connected in series with the switch 9, a voltage measuring unit 17 is connected in parallel to the input port 7 of each two-port of the chain, in addition to this current measuring unit 10. All other components of the battery control unit 4 and the charging control unit 5 are identical to those of the first embodiment, which is why they are not labeled with reference numerals in Figure 2 and are not described again here.

[0038] A fourth embodiment of an energy storage device 1 according to the invention is shown in Fig. 4. In contrast to the third embodiment, in the fourth embodiment a voltage measuring unit 17 is not connected in parallel to the input port 7 of each two-port of the chain, but between the terminal of the input port 7 that is connected to the switch 9 and the ground 18 of the battery control unit 4, which is connected to the negative terminal of the battery unit 2. All other components of the battery control unit 4 are identical to those of the first embodiment, which is why they are shown in Fig.

[0039] 2 are not marked with reference numbers and are not described again here.

[0040] In the associated charging control unit 5, one terminal of the switch 12 is connected, without an intermediate resistor, to a terminal of a voltage source, at which the voltage source outputs a voltage VI relative to the ground 14 of the charging control unit 5. No current measuring unit is provided between the other terminal of the switch 12 and the first terminal of the control interface 11. The second terminal of the control interface 11 is connected to the ground 14 of the battery charger 3 via a parallel connection of a resistor 13 and a voltage measuring unit 16. The ground 18 of the battery control unit 4 is connected to the ground 14 of the battery charger 3 via the line through which the negative terminals of the battery units 2 are connected to the negative terminal of the battery charger 3, which is not shown in Fig. 4 for clarity.In this embodiment, the circuit which serves for communication between the battery control units 4 and the battery charger 3 for initiating and terminating the charging process therefore runs via said connection between the negative terminals of the battery units 2 and the negative terminal of the battery charger 3.

[0041] In this embodiment, the charging control unit 5 determines whether the circuit is closed or not by measuring the voltage drop across the resistor 13 using the voltage measuring unit 16. The parallel connection of the resistor 13 and the voltage measuring unit 16 functions like a current measuring unit 15 in the first three embodiments and simultaneously fulfills the task of current limiting, which in the first three embodiments is performed by the resistor 13. A fifth embodiment of an energy storage device 101 according to the invention is shown in Fig. 5 in combination with an associated charging control unit 105. In this embodiment, each battery control unit 104 contains a current source 119, which is connected in series with a switch 109 and in parallel with the output port 108 of each two-port of the cascade circuit of Z.As in the first embodiment, a current measuring unit 110 is connected between one terminal of the input gate 107 and one terminal of the output gate 108 in each two-gate assembly, and the other terminals of the input gate 107 and the output gate 108 are directly connected to each other. In contrast to all other embodiments, the output gate 108 of the last two-gate assembly in the chain is not short-circuited here, but is open-circuited.

[0042] In this case, a current measuring unit 115, a switch 112, and a resistor 113 are connected in series between the two terminals of the control interface e 111 of the charging control unit 105. In this embodiment, a closed circuit exists as soon as at least one switch 109 of a two-port battery control unit 104 and the switch 112 of the charging control unit 105 are closed. Since all current sources 119 supply a current of the same magnitude, the current Ix through the current measuring unit 115 of the charging control unit 105 is an integer multiple of the current supplied by a single current source 119 when several switches 109 are closed. Therefore, the charging control unit 105 can determine, based on the measured current Ix, how many of the switches 109 are closed, i.e., how many battery units 102 are ready for charging.

[0043] While the other current measuring units 110 and all current measuring units in the other embodiments only have the function of determining whether a current is flowing or not, and all voltage measuring units 16 and 17 of the other embodiments only have the function of determining whether a voltage is greater or less than a threshold, the current measuring unit 115 used in this embodiment has the function of providing a measured value that can be compared by an evaluation device of the charging control unit 105 with several different thresholds in order to determine the number of closed switches 109.

[0044] The initiation and termination of the charging process in the first embodiment according to Fig. 1 is illustrated in Fig. 6 in the form of a flowchart. First, in step 21, the battery control unit 4 of a battery unit 2 ready for charging indicates its readiness by closing its switch 9. The charging control unit 5 of the battery charger 3 indicates its readiness for charging in step 22 by closing its switch 12. When all battery units 2 are ready for charging, a closed control circuit is formed, through which a current flows. This current can be detected by both the current measuring units 10 of the battery control units and the current measuring unit 14 of the charging control unit. When, in step 23, the flow of such a current is detected, and thus the closed state of all switches 9 is confirmed, the conditions for the start of the charging process are met.In this case, the battery control units 4 enable the battery units 2 for charging, and the charging control unit 5 of the battery charger switches on the charging current, thus initiating the charging of the battery units in step 24. Alternatively, the charging readiness of the battery units 2 can also be determined using the voltage detector 16. With the circuit open, the voltage VI is present across this detector. With the circuit closed, this voltage drops to a significantly lower value, which depends on the resistance of the current measuring units 10 and 15 and the circuit conductors.

[0045] The charging process can be terminated by each individual battery control unit 4 by opening its switch 9, thereby interrupting the current flow. This is detected, if necessary, in step 25 by the current measuring units 10 and 15 and / or by the voltage detector 16 based on the increase in voltage. In this case, the charging control unit 5 switches off the charging current in step 26, and the charging process is terminated. Alternatively, in step 26, the charging control unit can also signal the termination of charging by opening switch 12 or by switching off the voltage VI. This is then detected by the current measuring unit 10 in the battery control unit 4. It is also possible that the current flow in the control circuit is interrupted by removing the energy storage unit 1 from the battery charger 3, which results in the opening of all electrical contacts between these two system components.The crucial factor is the interruption of the current flow in the control circuit. The fieldbus 6 is not required in this embodiment. In this embodiment, the battery units 2 can only be charged together. If a single battery unit 2 is not ready for charging, the charging process is not started, and as soon as a single battery unit 2 loses its charging capability during an ongoing charging process, the charging process is aborted. The initiation and termination of the charging process in the second embodiment according to Fig. 2 is shown in Fig. 7 in the form of a flowchart. In the second embodiment, the charging process is initiated differently than in the first embodiment, namely by the charging control unit 5 closing its switch 12 in step 27 when ready for charging, while the switches 9 of all battery control units 4 are still open.This results in a voltage V2 dropping across the input gate 7 of the second gate of the first battery control unit 4, which is directly connected to the interface 11 of the charging control unit 5. This voltage is almost identical to the voltage VI supplied by the voltage source of the charging control unit 5.

[0046] After the voltage measuring unit 17 of the first battery control unit 4 detects this voltage V2 in step 28, the first battery control unit 4 sends a collective message via the fieldbus 6 to all other battery control units 4 in step 29, requesting them to signal their readiness to charge in step 30 by closing their respective switches 9. The subsequent sequence corresponds to that of the first embodiment; that is, the further steps 31 to 34 correspond to steps 23 to 26 of the sequence in the first embodiment and therefore do not require further explanation here. In the second embodiment as well, the charging process can only begin if all battery units 2 are ready to charge and it is aborted as soon as a battery unit 2 loses its charging capability.In this case, the termination of the charging process by the charging control unit 5 or by disconnection of the contacts between the battery unit 1 and the battery charger 3 is not detected by the voltage measuring unit 17, since the voltage at the input gate 7 is 0V immediately after the switch 9 is closed. Therefore, other methods must be used to detect the termination of the charging process by the battery control unit 4.

[0047] For the process according to Fig. 7, only the second port of the first battery control unit 4, whose input port 7 is directly connected to the interface 11 of the charging control unit 5, would actually require a voltage measuring unit 17 in parallel to the input port 7. However, for the sake of simplicity, all the second ports are equipped with such voltage measuring units here in order to ensure a uniform design of the battery control units 4 and arbitrary interchangeability of the battery units 2.

[0048] In the third embodiment according to Fig. 3, in which the two-ports of the battery control units 4 are equipped with both a current measuring unit 10 and a voltage measuring unit 17, the charging process can be initiated either as in the first embodiment as described with reference to Fig. 6 or as in the second embodiment as described with reference to Fig. 7. The additional current measuring unit 10 can also detect when the charging process is terminated by the charging control unit 5 or when the energy storage unit 1 is removed from the battery charger 3.

[0049] The initiation and termination of the charging process in the fourth embodiment according to Fig. 4 corresponds to the process described in Fig. 7 for the second embodiment, with the sole difference that the flow of current through the two-ports of all battery control units 4, and thus the closed state of the switches 9 of all battery control units 4 in the charging control unit 5, is detected not by a current measuring unit, but by a voltage measuring unit 16 in the form of a voltage drop across a resistor 13. The difference between the fourth and the second embodiments consists solely in a different circuit topology, in which the line between the parallel-connected negative terminals of the battery units 2 and the negative terminal of the battery charger 3 is used to connect the ground 18 of the battery control units 4 and the ground 14 of the battery charger.This allows the voltage of the voltage source VI to be fed back to the charging control unit 5 via the two-port connector, without sacrificing a common reference potential between the energy storage unit 1 and the battery charger 3. This ensures that a measurable voltage is present at the voltage measuring unit 17 even when the switch 9 is closed, and the additional current measuring unit 10 can detect both cases: termination of the charging process by the charging control unit 5 or removal of the energy storage unit 1 from the battery charger 3.

[0050] The initiation and termination of the charging process in the fifth embodiment according to Fig. 5 is illustrated in Fig. 8 in the form of a flowchart. The process begins, as in the first embodiment, with the battery control unit 104 indicating the readiness of a battery unit 102 to be ready for charging in step 35 by closing its switch 109. The charging control unit 105 of the battery charger 103 indicates its readiness for charging in step 36 by closing its switch 112. When at least one battery unit 102 is ready for charging, a closed circuit is already established, through which a current Ix flows. This current can be detected in step 37 by the current measuring units 110 of the battery control units 104 and can also be measured by the current measuring unit 115 of the charging control unit.If several switches 109 are closed, this current is a multiple of the current supplied by a power source 119, since all power sources are identical.

[0051] If no current Ix is detected, the charging process is terminated in step 41 before it has begun. If a current Ix is flowing, an evaluation unit of the charging control unit 105 determines the number of closed switches 109 from the measured value of the current Ix in step 38, and thus the number of battery units 102 ready for charging, and adjusts the charging current of the battery charger 103 accordingly. Furthermore, the battery control units 104 of the battery units 102 ready for charging enable them for charging, and the charging of the battery units 102 ready for charging begins in step 39.

[0052] During charging, step 40 monitors whether the current Ix changes, which can be caused by the opening or closing of individual switches 109 of battery control units 104. If so, step 37 first checks whether the current Ix is not zero. If so, the charging process is terminated by switching off the charging current in step 41. Otherwise, in step 38, the charging current is set to a new value that corresponds to the total current requirement of all currently chargeable battery units 102. The set charging current can either decrease or increase. The loop of steps 37 to 40 is executed until step 37 detects that the value of the current Ix has become zero, at which point the charging process is terminated in step 41.

[0053] It is evident that in the fifth embodiment, unlike the other embodiments, not only can all battery units 102 be charged simultaneously, but the charging current can also be adjusted to how many battery units 102 are ready for charging, so that only a portion of the battery units 102 can be charged. The charging process can begin even if not all battery units 102 are ready for charging, and it does not need to be interrupted if a battery unit 102 loses its readiness to be charged. This is a particular advantage of the fifth embodiment, which is based on the fact that, due to the active current supply by the current sources 119 of the battery control units 104 and the measurement of the total current Ix by the current measuring unit 119, the number of battery units 102 ready for charging can be determined by the charging control unit 105.

[0054] As can be seen from the preceding description, the electrical energy storage device and the electrical battery charger according to the invention are coordinated in their construction and operation and together form an electrical energy storage system, wherein different energy storage units can be combined with different battery chargers. Reference numeral

[0055] 1; 101 Energy storage device

[0056] 2; 102 battery unit

[0057] 3; 103 Battery charger

[0058] 4; 104 Battery control unit

[0059] 5; 105 Charging control unit

[0060] 6; 106 Fieldbus

[0061] 7; 107 Entrance gate

[0062] 8; 108 Exit Gate

[0063] 9; 109 switches

[0064] 10; 110 current measuring unit

[0065] 11; 111 Interface

[0066] 12; 112 switches

[0067] 13; 113 Resistance

[0068] 14 Masse

[0069] 15; 115 Current measuring unit

[0070] 16 Voltage measuring unit

[0071] 17 Voltage measuring unit

[0072] 18 Masse

[0073] 119 Power source

[0074] 21 - 41 procedural steps

Claims

Claims 1. Electrical energy storage device (1; 101) with a plurality of battery units (2; 102) connected in parallel, each comprising a rechargeable battery for storing energy and a battery control unit (4; 104) for controlling the absorption and release of energy by the battery unit (2; 102) via a power circuit, characterized in that each battery control unit (2; 102) comprises a two-port with a two-pole input port (7; 107) and a two-pole output port (8; 108), and that the two-ports are connected in a chain by connecting the output port (8; 108) of one two-port to the input port (7; 107) of an adjacent two-port such that by connecting a voltage or current source to the input port (7; 107) of the first two-port and short-circuiting the output port (8;108) of the last two-port of the chain, a control circuit leading through all two-ports, separate from the power circuit, can be established, and that each two-port has a switch (9; 109) that can be actuated by the battery control unit (4; 104), by which the current flowing at the input port (7; 107) can be changed.; 2. Electrical energy storage device (1; 101) according to claim 1, characterized in that the switch (9; 109) of a two-port is closed when the battery unit (2; 102) is ready to be charged, and is open when the battery unit (2; 102) is not ready to be charged.

3. Electrical energy storage device (1; 101) according to claim 1 or 2, characterized in that each two-port has a current measuring unit (10; 110) for a current flowing at the input port (7; 107) and / or a voltage measuring unit (17) for a voltage applied at the input port (7).

4. Electrical energy storage device (1) according to one of claims 1 to 3, characterized in that the switch (9) is connected between a terminal of the input gate (7) and a terminal of the output gate (8) of the second gate of a battery control unit (4), that the respective other terminals of the input gate (7) and the output gate (8) of the second gate of a battery control unit (4) are directly connected to each other, and that the output gate (8) of the last second gate of the chain is short-circuited.

5. Electrical energy storage device (1) according to one of claims 1 to 4, characterized in that a voltage measuring unit (17) is connected in parallel to the input port (7) of the two-port or between a terminal of the input port (7) connected to the switch (9) and the negative terminal of the battery unit (2), and that the output port (8) of the last two-port of the chain is short-circuited.

6. Electrical energy storage device (101) according to one of claims 1 to 3, characterized in that the switches (109) and a power source (119) are connected in series between the terminals of the output port (108) of each two-port, that one terminal of the input port (107) and the output port (108) are directly connected to each other, and that the other terminal of the output port (108) is connected to the other terminal of the input port (107) in such a way that a control circuit separate from the power circuit can be established by connecting a resistor to the input port (107).

7. Electrical energy storage device (1) according to claim 6, characterized in that a current measuring unit (110) is connected between the other terminal of the input gate (107) and the series circuit of the switch (109) and the current source (119).

8. Electrical energy storage device (1) according to one of claims 1 to 7, characterized in that the battery control units (4; 104) are connected to each other via a fieldbus (6; 106).

9. Electric battery charger (3; 103) with a charging interface for supplying charging current to a rechargeable battery and with a charging control unit (5; 105), characterized in that the charging control unit (5; 105) for communication with battery control units (4; 104) of battery units (2; 102) of an electrical energy storage device (1; 101) has a two-pole control interface e (11; 111) separate from the charging interface and a current measuring unit (15; 115) for a current flowing via the control interface (11; 111) and / or a voltage measuring unit (16) for a voltage applied to the control interface (11; 111).

10. Electric battery charger according to claim 9, characterized in that the charging control unit (5; 105) has a switch (12; 112) that it can actuate, by which a current flowing via the control interface (11; 111) and / or a voltage present at the control interface (11; 111) can be changed, and that the current or voltage is switched on by the switch (12; 112) when the battery charger (3; 103) is ready to charge, and is switched off when the battery charger (3; 103) is not ready to charge.

11. Electric battery charger according to claim 10, characterized in that the charging control unit (5) has a voltage or current source which can be switched on by the switch (12) to supply a voltage and / or a current to the control interface (11).

12. Electric battery charger according to claim 10, characterized in that the charging control unit (105) has an electrical resistor (113) which can be switched to the control interface by means of the switch (112).

13. Method for charging an electrical energy storage device (1; 101) according to one of claims 1 to 8 using an electrical battery charger (3; 103) according to one of claims 9 to 12, characterized by the following steps: - Establishing a control circuit separate from the charging circuit, running through the charging control unit (5; 105) of the battery charger (3; 103) and the battery control unit (4; 104) of at least one battery unit (2; 102) ready for charging of the energy storage device (1; 101), by closing switches (12, 9; 112, 109) in the charging control unit (5; 105) and in the battery control unit (4; 104) of the battery unit (2; 102) ready for charging - Detecting the closed state of the manufactured control circuit by measuring the current flowing in it by a current measuring unit (15) or a voltage caused by the current by a voltage measuring unit (16) in the charging control unit (5; 105), Supply of a charging current by the battery charger (3; 103) to the battery units (2; 102) if and as long as the current measuring unit (15; 115) or the voltage measuring unit (16) of the charging control unit (5; 105) detects the flow of a current in the control circuit.

14. Method according to claim 13, characterized in that the battery control unit (4; 104) of a battery unit (2; 102) interrupts the part of the control circuit running through it when the battery unit (2; 102) is no longer ready to be charged, and / or that the charging control unit (5; 105) interrupts the part of the control circuit running through it when the battery charger (3; 103) is no longer ready to be charged.

15. Method according to claim 13 or 14, characterized in that the battery control unit (104) of a battery unit (102) ready for charging feeds a current into the control circuit by means of its own power source (119) when this is closed, and that the charging control unit (105) adjusts the charging current supplied by it to the battery units (102) depending on the value of the current in the control circuit which is measured by its current measuring unit (115).

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