DISCHARGING OR CHARGING OF BATTERY MODULES

Abstract

A method for controlling the discharging or charging of a group of one or more battery modules able to be interconnected in parallel, wherein the module voltages of the battery modules are ascertained and a highest or lowest module voltage is ascertained from the ascertained module voltages and only battery modules whose module voltage differs from the highest or lowest module voltage by less than a predefined activation difference are interconnected, and a battery module for use in a group of at least two battery modules able to be interconnected in parallel, wherein the battery module has at least one power connection and a battery unit connected thereto via a switch, wherein the battery module furthermore has a voltmeter for measuring the voltage of the battery unit and a module controller connected to the voltmeter and the switch, wherein the module controller has at least one data bus connection and is designed, in the event of connection to a data bus, to provide a voltage ascertained by the voltmeter on the data bus and to open the switch in response to a control command received on the data bus.

Claims

1. A method for controlling the discharging of a group of one or more battery modules interconnectable in parallel, wherein the module voltages of the battery modules are determined, wherein a highest module voltage is determined from the determined module voltages and only those battery modules whose module voltage differs from the highest module voltage by less than a predefined activation difference are interconnected.

2. The method according to claim 1, wherein the module voltages and on this basis the interconnected battery modules are re-determined at regular intervals.

3. The method according to claim 1, wherein the predefined activation difference is less than 1% of the nominal voltage of a battery module.

4. The method according to claim 1, wherein an output power of the group is dynamically limited depending on the interconnected battery modules.

5. A method for controlling the charging of a group of one or more battery modules interconnectable in parallel, wherein the module voltages of the battery modules are determined, wherein a lowest module voltage is determined from the determined module voltages and only those battery modules whose module voltage differs from the lowest module voltages by less than a predefined activation difference are interconnected.

6. The method according to claim 5, wherein the module voltages and on this basis the interconnected battery modules are re-determined at regular intervals.

7. The method according to claim 5, wherein the predefined activation difference is less than 1% of the nominal voltage of a battery module.

8. The method according to claim 5, wherein a charging current of the group is dynamically adapted depending on the interconnected battery modules.

9. A battery module for use in a group of at least two battery modules interconnectable in parallel, wherein the battery module has at least one power connection and a battery unit connected thereto via a switch, wherein the battery module furthermore has a voltage measuring device for measuring the voltage of the battery unit, wherein the battery module has a module controller connected to the voltage measuring device and the switch, wherein the module controller has at least one data bus connection and is adapted, when connected to a data bus, to provide a voltage determined by the voltage measuring device on the data bus and to open the switch in response to a control command received on the data bus.

10. The battery module according to claim 9, wherein the battery unit comprises at least one lithium-ion cell.

11. The battery module according to claim 9, wherein the data bus is a serial data bus, according to RS-485 or CAN bus.

12. The battery module according to any claim 9, wherein the battery module comprises at least one mechanical coupling for connection to a further battery module, wherein a power connection and a data bus connection are arranged in such a manner that a further battery module connected via the mechanical coupling participates on the same data bus and the two battery modules are interconnectable in parallel.

13. The battery module according to claim 12, wherein the mechanical coupling comprises a thread.

14. The battery module according to claim 9, wherein the battery module is suitable for use under water.

15. The battery module according to claim 9, wherein the at least one power connection and/or the at least one data bus connection comprise spring-loaded electrical contacts.

16. The battery module according to claim 9, wherein the battery unit has a maximum energy content of 100 Wh.

17. The battery module according to claim 9, wherein the battery module has a carrying device comprising a handle.

18. A group comprising at least two battery modules according to claim 9, wherein the battery modules are participants on the same data bus and are interconnectable in parallel.

19. A load module for connection to a group of one or more battery modules interconnectable in parallel, wherein the load module has a power connection and an electrical load connected thereto, characterized in that the load module has a group controller with a data bus connection, wherein the group controller is adapted to receive determined module voltages from connected battery modules when connected to a data bus, to determine a highest module voltage from the received module voltages and to send a control command for parallel switching only to those battery modules whose module voltage differs from the highest module voltage by less than a predefined activation difference.

20. The load module according to claim 19, wherein the group controller is further adapted to dynamically limit an output power of a connected group of battery modules depending on the interconnected battery modules.

21. A charging device for connection to a group of one or more battery modules interconnectable in parallel, wherein the charging device has power connections and an electrical voltage source connected thereto, wherein the charging device has a group controller with a data bus connection, wherein the group controller is adapted to receive determined module voltages from connected battery modules when connected to a data bus, to determine a lowest module voltage from the received module voltages and to send a control command for parallel switching only to those battery modules whose module voltage differs from the lowest module voltage by less than a predefined activation difference.

22. The charging device according to claim 21, wherein the group controller is further adapted to dynamically adapt a charging current for a connected group of battery modules depending on the interconnected battery modules.

Description

[0029] The invention will be described in further detail hereinafter with reference to optional exemplary embodiments to which it should not however be restricted and with reference to the drawings. In the drawings in detail:

[0030] FIG. 1 schematically shows a block diagram with a group of two battery modules and a load module connected thereto;

[0031] FIG. 2 schematically shows a diagrammatic view of a battery module with the viewing direction onto a front side;

[0032] FIG. 3 schematically shows a diagrammatic view of a battery module according to FIG. 2 with the viewing direction onto a rear side;

[0033] FIG. 4 schematically shows a side view of two consecutively aligned battery modules directly before a mechanical connection of the battery modules; and

[0034] FIG. 5 shows schematically a sequence diagram to show a method for controlling the discharging of a group of three battery modules.

[0035] FIG. 1 shows schematically a circuit diagram of a group 1 comprising a first battery module 2 and a second battery module 3 as well as a load module 4 connected to the group 1. The two battery modules 2, 3 are interconnectable in parallel. For this purpose, each battery module 2, 3 has a switch 5, 6. If the switches 5, 6 are closed, the battery modules 2, 3 are interconnected in parallel.

[0036] Each battery module 2, 3 has two power connections 7, 8 with respectively two electrical contacts 9, 10, 11, 12. Respectively one battery unit 13 is connected to the power connections 7, 8 via the respective switch 5, 6. The battery units 13 each comprise a plurality of lithium-ion cells. Overall, each battery unit 13 has a specific maximum energy content, e.g., about 100 Wh.

[0037] The battery modules 2, 3 have a voltage measuring device 14 for measuring the voltage of the battery unit 13. One module controller 16 is connected to the voltage measuring device 13 and the switch 5, 6, more precisely a driver 15 for the switches 5, 6, respectively. The module controller 16 has a data bus connection 17. The module controller 16 is adapted in this case to provide a voltage determined by the voltage measuring device 14 on the data bus 18 when connected to a data bus 18 and to open (or close) the switch 5, 6 of the relevant battery module 2, 3 in response to a control command received on the data bus 18. The data bus 18 is a serial data bus according to RS-485. The two battery modules 2, 3 participate on the same data bus 18.

[0038] In addition, a short-circuit protective circuit 19 is connected to the driver 15. The module controller 16 is additionally connected to a temperature monitor 20 which is adapted for monitoring the temperature of the battery unit 13. The module controller 16 can provide a temperature of the battery unit 13 obtained by the temperature monitor 20 on the data bus 18. The data bus 18 has separate supply lines 21 for supplying power to the bus participants. For displaying the charging state, each of the battery modules 2, 3 has an LED display 22 with a series of LEDs 23.

[0039] The load module 4 is connected to the group of battery modules 2, 3. This module has a power connection 24 with two electrical contacts 25, 26 and an electrical load connected therewith in the form of an electric motor 27. The load module 4 has a group controller 28 connected to the data bus 18 with a data bus connection 29. The group controller 28 is adapted to receive determined module voltages from the connected battery modules 2, 3, to determine a highest module voltage from the received module voltages and to send a control command for parallel switching only to those battery modules 2, 3 whose module voltage differs from the highest module voltage by less than a predefined activation difference. The group controller 28 is connected to a charge state monitor 30. The load module 4 has a motor control unit 31 for regulating the direction of rotation and speed of the electric motor 27.

[0040] FIGS. 2 to 4 show schematically an exemplary mechanical configuration of a single battery module 2 (FIGS. 2 and 3) or two battery modules 2, 3 (FIG. 4) for use under water. The battery module 2 has a mechanical coupling 34, 35 for connection to a further battery module 3 both on a front side 32 and on a rear side 33. The power connection 7 and the data bus connection 17 are arranged in such a manner that a further battery module 3 connected via the mechanical coupling 34, 35 participates on the same data bus 18 and the two battery modules 2, 3 are interconnectable in parallel (as according to FIG. 1). Both mechanical couplings 34, 35 each have a thread. The data bus connections 17 comprise spring-loaded electrical contacts.

[0041] The housing 36 of the battery module 2 can, for example, be made of aluminium. A carrying device in the form of a foldable handle 37 is provided on the housing 36.

[0042] The sequence diagram shown in FIG. 5 illustrates the communication between the load module 4 and the battery modules 2, 3, 38. The messages shown in the sequence diagram are exchanged via the data bus 18. The load module 4, more precisely the group controller 28, after activation of the load module 4 sends a request 39 via the data bus 18 to connected battery modules. The first battery module 2 that receives the request 39 sends an acknowledgement 40. The acknowledgement 40 comprises the serial number (e.g., “100”) and the current module voltage (e.g., “33.820 V”) of the battery module 2. After the first acknowledgement 40, the group controller 28 sends a further request 41. The first battery module 2 does not respond again on account of the acknowledgement 40 that has already been sent. The request 41 then arrives at the second battery module 3 as the next one, which then sends a second acknowledgement 42 to the group controller 28. The second acknowledgement 42 contains the serial number (e.g., “200”) and the current module voltage (e.g., “33.820 V”) of the second battery module 3. As a result of the renewed acknowledgement 42, the group controller sends a third request 43 which is answered by the third battery module 38 with its serial number (e.g., “n”) and module voltage (e.g., “33.430 V”) (acknowledgement 44). The group controller 28 compares the module voltages obtained and determines the highest module voltage (here, e.g., “33.820 V”). On this basis those battery modules whose module voltage lies within an activation difference of, e.g., 0.1 V, i.e., in a voltage range of 33.720 V to 33.820 V, is activated. In the example described here the module voltages of the first and second battery module 2, 3 lie within this range. Thus, control commands 45, 46 are sent to the first and the second battery module 2, 3 in order to interconnect these battery modules 2, 3. The two activated battery modules 2, 3 then send activation confirmations 47, 48 back to the group controller 28.

[0043] The following part of the sequence diagram shows an alternative sequence for a later point in time when only one request 49 is sent by the group controller 28 which reaches all the battery modules 2, 3, 38. Each of the battery modules 2, 3, 38 then sends an acknowledgement 50, 51, 52 with its serial number and module voltage back to the group controller 28. At this time the module voltage of the first and second battery module has decreased, e.g., to 33.430 V. The module voltage of the third battery module 38 now lies within the activation difference and the third battery module 38 is therefore activated by control command 53 from the group controller 28. After its activation this module sends a confirmation 4 back to the group controller 28.