Electric battery unit and electric power storage system

Abstract

The invention relates to an electric battery unit (1) having a rechargeable battery (2), a first external interface (6, 8) for feeding in and outputting electrical power, a first switching unit (4) which is connected between the first external interface (6, 8) and the battery (2) and is connected to an internal control unit (3) by means of which a current path between the battery (2) and the first external interface (6, 8) can be closed and interrupted by means of the first switching unit (4), said electric battery unit having a second external interface (8) for outputting electric power from the battery unit (1) and a second switching unit (5) which is connected between the second external interface (7, 8) and the battery (2). The current path between the battery (2) and the second external interface (7, 8) can be closed and interrupted by the internal control unit (3) independently of the current path between the battery (2) and the first external interface (6, 8) by means of the second switching unit (5).

Description

[0001] Electric battery unit

[0002] and electrical energy storage system

[0003] The invention relates to an electrical battery unit according to the preamble of claim 1 and an electrical energy storage system according to the preamble of claim 5.

[0004] A rechargeable battery, which is an assembly of electrochemical cells, or a battery pack consisting of several batteries connected together, can be used to power a mobile machine. Such a battery is often equipped with a battery management system (BMS) to switch it on and off as needed and to ensure that it is charged and discharged within safe limits of current, voltage, charge, and temperature. A battery is typically switched off to conserve energy when the machine it powers is not in operation. If the machine normally operates without a human operator, as is the case with an automated guided vehicle (AGV), it is often desirable to switch the battery on and off automatically and / or via a radio signal.However, if the battery is the only energy source for the machine, then automatic or remote activation is not possible, as the necessary components are not powered by the switched-off battery.

[0005] From DE 1020122213159 A1, a battery system is known whose battery can be connected to a DC link via at least one contactor, and which has a diagnostic device for diagnosing the condition of the contactor, in particular for detecting a fault. The diagnostic device includes a monitoring circuit with a first branch in which the contactor is arranged, and with a second branch connected in parallel thereto in which a voltage source for generating a reference voltage is connected.

[0006] German patent DE 102013220609 discloses an energy supply system for a vehicle electrical system with at least one energy storage device, an electrical system connection, and an energy storage management system with a supply connection through which it can be supplied with electrical energy. The energy storage device can be connected to the electrical system connection via a first switch. The supply connection can be selectively connected to either the energy storage device or the electrical system connection via a second switch. Both switches are controlled by the energy storage management system depending on the current status data of the energy storage device.

[0007] German patent DE 102015002070 discloses a battery cell for a motor vehicle battery comprising a galvanic cell, two electrical terminals, a control unit, and at least one switching element controllable by the control unit, by means of which an electrically conductive connection between a conductor of the galvanic cell and at least one of the electrical terminals can be established or interrupted. The control unit is connected to a battery management system via an interface.

[0008] From DE 102018202680 A1, a diagnostic device for a current interruption device is known, which is arranged in a current path to an energy storage device of a vehicle. The diagnostic device switches the current interruption device between an open state and a closed state or vice versa and checks the state of the current interruption device based on the voltage drop between its terminals during such a switch.

[0009] German patent DE 102018203997 A1 discloses a battery, particularly for a motor vehicle, comprising several electrically interconnected battery cells, each containing a cell branch with a galvanic cell and a bypass branch for bridging the respective galvanic cell. Both branches each contain a switching element for opening and closing the branch, which can be controlled by a control unit of the battery, thereby allowing the individual battery cells to be selectively connected or bypassed to meet a predefined requirement.

[0010] US Patent 2024 / 0162734 A1 discloses a battery arrangement with multiple electrical battery cells, a control circuit with two control circuit branches through which the terminals of the battery arrangement can be connected to the terminals of an electrical load, at least one semiconductor device located between the battery arrangement and the load and controlling the electrical current between them, and a switching device with at least one mechanical switch located in an electrical connection between the two control circuit branches to electrically connect and disconnect them.

[0011] Based on this prior art, the invention aims to enable automatic or remote switching on of a switchable battery.

[0012] This problem is solved according to the invention by an electrical battery unit with the features of claim 1 and by an electrical energy storage system with the features of claim 5. Advantageous embodiments of the invention are specified in the respective dependent claims.

[0013] An inventive electrical battery unit with a rechargeable battery for storing energy, with a first external interface through which electrical power can be fed into and out of the battery unit, with a first switching unit connected between the first external interface and the battery, which is connected to an internal control unit, through which a current path between the battery and the first external interface can be closed and interrupted by means of the first switching unit, has a second external interface for supplying electrical power from the battery unit and a second switching unit connected between the second external interface and the battery, which is connected to the internal control unit,and the current path between the battery and the second external interface can be closed and interrupted by the internal control unit using the second switching unit, independently of the current path between the battery and the first external interface.

[0014] This makes it possible to supply power to an external unit for the automatic or remote closure of the power path between the battery and the first external interface—i.e., for activating the battery unit as a power source—even when said power path is interrupted, without requiring an additional external battery to power the unit. The functionality of the automatic or remote activation of the battery unit would then depend on the charge level of this external battery. Furthermore, this also allows the functionality of other electronic components of the overall system, which is powered by the battery unit, to be maintained if the power path between the battery and the first external interface is interrupted due to a defect in the connected power consumer or to throttle battery discharge.

[0015] It is advantageous if the current flowing between the battery and one of the external interfaces can be limited to a predetermined maximum value by the respective switching unit. This prevents battery overload, especially in the event of an external short circuit.

[0016] It is advantageous if the maximum value of the current between the battery and the second external interface is smaller than the maximum value of the current between the battery and the first external interface, since the second external interface is intended to supply power to a consumer with comparatively low power requirements.

[0017] It is also advantageous if the switching units are configured to interrupt the current paths between the battery and the external interfaces when the battery voltage falls below predetermined thresholds, and if the predetermined threshold for interrupting the current path by the second switching unit is lower than the threshold for interrupting the current path by the first switching unit. This prevents excessive battery discharge and maintains the power supply to a load with comparatively low power requirements connected to the second external interface for as long as possible.

[0018] Preferably, the electrical energy storage system according to the invention comprises an external control unit connected to the internal control unit, by which the internal control unit can trigger the closing or interruption of the current path between the battery and the first external interface, and the external control unit is connected to the second external interface of the battery unit for its power supply. This ensures that the external control unit can trigger the closing of said current path at any time, provided the internal control unit permits this based on the battery's status as determined by the internal control unit. Preferably, the external control unit has a receiver for wirelessly receiving signals, upon receipt of which the external control unit triggers the internal control unit to close or interrupt the current path between the battery and the first external interface.This enables wireless remote control of switching the first interface on and off.

[0019] Furthermore, it is advantageous if the internal control unit can be switched between a normal operating mode and a low-power standby mode by the external control unit, and if the switchover can be triggered by signals received wirelessly from the external control unit. This allows for a significant reduction in battery discharge when the battery is not needed.

[0020] The battery unit preferably contains the battery, the switching units, the internal control unit, and the external interfaces as components of a single assembly, while the external control unit is a separate assembly. This allows for a compact design of the battery unit on the one hand and application-specific configuration of the external control unit on the other.

[0021] Preferably, a DC-DC converter is connected between the battery and the external control unit. This converter reduces the voltage supplied to the external control unit to a value lower than the voltage supplied by the battery. This is necessary if the external control unit has an operating voltage lower than the battery voltage. The DC-DC converter can be implemented as an internal component of the battery unit or as a separate component.

[0022] The electrical energy storage system according to the invention can comprise a plurality of battery units whose first external interfaces are connected in parallel and whose second external interfaces are also connected in parallel. In this case, only a single external control unit is provided, connected to the internal control units of all battery units and powered by the second external interfaces of the battery unit. By connecting several battery units, a larger charge capacity or a higher voltage than that of a single battery can be provided if required. By implementing the external control unit as a separate component, hardware can be saved in such a configuration, since only one instance of the external control unit is needed.

[0023] In an electrical energy storage system with multiple interconnected battery units, it is advantageous to use a single DC-DC converter between the parallel-connected secondary external interfaces of the battery units and the external control unit. This converter should supply a lower voltage to the external control unit than the voltage present at the secondary external interfaces. When connecting multiple battery units, only one DC-DC converter is required to provide the appropriate supply voltage for the external control unit, thus saving on hardware. It goes without saying that the DC-DC converter must be implemented as a separate component from the battery unit.

[0024] In an electrical energy storage system with multiple battery units, it can be advantageous, depending on the application, to connect their first external interfaces in series. Even then, only a single external control unit is required, connected to the internal control units of all battery units. This control unit is powered by the second external interface of one of the battery units. If necessary, a DC-DC converter can also be connected between the second external interface of the battery unit and the external control unit.

[0025] Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. These show

[0026] Fig. 1 shows a schematic representation of a battery unit according to the invention and

[0027] Fig. 2 schematic representation of an inventive energy storage system.

[0028] A battery unit 1 according to the invention, as shown in Fig. 1, comprises a rechargeable battery 2, a control unit 3, a first switching unit 4, a second switching unit 5, a first positive terminal 6, a second positive terminal 7, and a negative terminal 8. The battery unit 2 consists of a plurality of electrochemical cells, from which supplied electrical power can be stored in the form of chemical energy and released again as electrical power when required. The input and output of electrical power is effected via the first positive terminal 6 and the negative terminal 8, to which lines 9 and 10 are connected for connection to an electrical load, such as an electric motor, or to a charging device. The first positive terminal 6 and the negative terminal 8 together form a first external interface 6, 8 of the battery unit 1 for inputting or outputting electrical power to or from the battery unit 1.

[0029] The first positive terminal 6 is not directly connected to the positive terminal of battery 2, but via the first switching unit 4, while the negative terminal 8 is directly connected to the negative terminal of battery 2. One function of the first switching unit 4 is to close the current path between the positive terminal of battery unit 2 and the first positive terminal 6 when battery 2 is to supply or receive power via lines 9 and 10, and to interrupt this current path when battery 2 reaches a predetermined minimum permissible state of charge during power supply or a predetermined maximum permissible state of charge during power consumption, or when a fault occurs, e.g., in the form of a short circuit, or when power from battery unit 2 is temporarily not required. In the latter case, the interruption serves to maintain the state of charge of battery 2.Another function of the first switching unit 4 is to limit the current flowing through the battery unit 2 to a maximum permissible value in order to prevent overloading the battery 2. For this purpose, the first switching unit 4 contains suitable semiconductor components such as power MOSFETs or an electromechanical contactor.

[0030] The first switching unit 4 is controlled by the control unit 3, which is also commonly referred to as the battery management system. The control unit 3 must be constantly ready for operation and is therefore powered directly by the battery 2, as shown in Fig. 1 by corresponding lines. However, it has a low-power standby mode, which it can be put into by an external signal if the battery 2 is to be temporarily taken out of service. In this case, before entering standby mode, it activates the switching unit 4 to interrupt the current path running through it. The control unit 3 can be switched from standby mode to its normal operating mode by an external wake-up signal.To ensure that, even when the energy storage unit 1 is on board a vehicle, the control unit 3 can be switched between normal operating mode and standby mode from an external station not connected to the vehicle via cables, in order to close the current path leading through the first switching unit 4, an external control unit 11 is provided. This external control unit contains a receiver for a wirelessly transmitted signal, such as a radio signal. The external control unit 11 is connected to the internal control unit 3 and, upon receiving a corresponding external signal 13, sends it a signal that triggers the transition from normal operating mode to standby mode or vice versa. After the transition to normal operating mode, the internal control unit 3 can control the first switching unit 4 to close the current path leading through it. To enable this, the external control unit 11 must be constantly, i.e., continuously, powered on.even when the control unit 3 is in standby mode and the current path leading through the first switching unit 4 is interrupted, it will be supplied with power.

[0031] The external control unit 11 can comprise several subunits. For example, in addition to a radio unit, it can also include a digital interface unit and a communication unit for communication via a fieldbus such as CAN bus. The second positive terminal 7, which together with the negative terminal 8 forms a second external interface 7, 8 of the battery unit 1, serves to supply power to the control unit 11. This interface is solely for supplying electrical power from the battery 2. The second positive terminal 7 is also not directly connected to the positive terminal of the battery unit 2, but rather via the second switching unit 5. One function of the second switching unit 5 is to close the current path between the positive terminal of the battery 2 and the second positive terminal 7 when the battery unit 2 is to supply power via the second positive terminal 7 and the negative terminal 8, and to interrupt this current path when a fault occurs, e.g.,in the form of a short circuit or insufficient battery voltage. Another function of the second switching unit 5 is to limit the current flowing through the second positive terminal 7 to a maximum permissible value, which is lower than the maximum value of the current limited by the first switching unit 4 and depends not only on the current-carrying capacity of the battery unit 2, but also on the expected current demand of the external control unit 11 connected between the second positive terminal 7 and the negative terminal 8. The second switching unit 5 also contains suitable semiconductor components such as power MOSFETs.If the supply voltage required by the external control unit 11 is significantly lower than the voltage of battery 2, which is usually the case, a DC-DC converter 12 is connected between the positive terminal of battery 2 and the second positive terminal 7, in addition to the switching unit 5. This converter reduces the voltage of battery 2 to the supply voltage of the external control unit 11. The DC-DC converter 12 is connected between the second switching unit 5 and the second positive terminal 7, but the order of the second switching unit 5 and the DC-DC converter 12 could also be reversed. Furthermore, the DC-DC converter 12 could also be implemented as a separate component from the battery unit 1, instead of being an internal component of the battery unit 1, as shown by way of example in Fig. 1.It is understood that the DC voltage converter 12 requires a reference potential in the form of a connection to the negative terminal of the battery 1, which is not shown in Fig. 1 for the sake of simplicity.

[0032] Fig. 2 shows an energy storage system according to the invention, comprising several battery units 1 of the type shown in Fig. 1 and described above, with one modification that will be explained below. Depending on requirements, the energy storage system could also contain only two or more than the three battery units 1 shown in Fig. 2. The individual components of a battery unit 1 are numbered only once, by way of example, in the leftmost of the three battery units 1 shown, as in Fig. 1.

[0033] The corresponding terminals 6 and 8 of the individual battery units 1, which together form the respective first external interface of each battery unit 1 for supplying or supplying electrical power, are all connected in parallel to provide a multiple of the capacity of a single battery 2. However, these terminals 6 and 8 could also be connected in series to provide a multiple of the voltage of a single battery 2, or a combination of parallel and series connection could be used. In a series connection, however, the second external interfaces 7 and 8 are not connected in parallel; instead, this interface of one of the battery units is used to supply power to the external control unit 11.

[0034] The external second control unit 11 has the same functions as previously described for an energy storage system with only a single battery unit 1. However, in the system configuration with multiple battery units 1, it is connected to the internal first control units 3 of all battery units 1 in order to switch all first control units 3 between normal operating mode and low-power standby mode, and to close and open the current paths leading through the first switching units 4 of all battery units 1 via their first control units 3.These functions can also be triggered individually by a single external control unit 11 at the various battery units 1 if required, by means of an addressing in the signals sent by the external control unit 11 to the internal control units 3, by means of which it can be recognized for each individual internal control unit 3 whether a signal from the external control unit 11 is intended for it or not.

[0035] However, it is also possible to forgo such individual addressing and leave the coordination of the function of the individual battery units 1 to their internal control units 3, for which purpose the latter can communicate with each other via a fieldbus. The external control unit 11 can perform other control tasks beyond switching the battery units 1 on and off, such as communication with the vehicle or a central unit, switching outputs, and reading sensor signals and other data.

[0036] As can be seen in Fig. 2, only a single DC-DC converter 12 is connected between the parallel-connected external interfaces 7, 8 of the battery units 1 and the external control unit 11 to supply power to the single external control unit 11, since it would not be necessary to provide a separate DC-DC converter 12 for each battery unit 1 as in Fig. 1. It is understood that in this configuration, the DC-DC converter 12 must be a separate component from the battery units 1. However, it could be combined with the external control unit 11 to form a single component.

[0037] In principle, it would also be possible for the battery unit 1 to have only one positive terminal and two negative terminals instead of two positive terminals 6 and 7 and a single negative terminal 8, and for the switching units 4 and 5 to be connected between the negative terminal of the battery 2 and each of these negative terminals. The embodiment of the battery unit 1 described above is therefore not to be understood as a limitation of the scope of protection of the patent claims. 5 Reference numerals

[0038] 1 battery unit

[0039] 2 batteries

[0040] 3 internal control unit

[0041] 4 first switching unit

[0042] 5 second switching unit

[0043] 6 first positive terminal

[0044] 7 second positive terminal

[0045] 8 Negative terminal

[0046] 9 Management

[0047] 10 Management

[0048] 11 external control unit

[0049] 12 DC / DC converters

[0050] 13 external signals

Claims

Claims 1. An electrical battery unit (1) comprising a rechargeable battery (2) for storing energy, comprising a first external interface (6, 8) through which electrical power can be supplied to and supplied from the battery unit (1), comprising a first switching unit (4) connected between the first external interface (6, 8) and the battery (2), which is connected to an internal control unit (3) through which a current path between the battery (2) and the first external interface (6, 8) can be closed and interrupted by means of the first switching unit (4), characterized in that it has a second external interface (7, 8) for supplying electrical power from the battery unit (1), and that it has a second switching unit (5) connected between the second external interface (7, 8) and the battery (2), which is connected to the internal control unit (3).and that the current path between the battery (2) and the second external interface (7, 8) can be closed and interrupted by the internal control unit (3) by means of the second switching unit (4) independently of the current path between the battery (2) and the first external interface (6, 8).

2. Electrical battery unit according to claim 1, characterized in that a current flowing between the battery (2) and one of the external interfaces (6, 8; 7, 8) can be limited to a predetermined maximum value by the respective intermediate switching unit (4; 5).

3. Electrical battery unit according to claim 2, characterized in that the maximum value of the current between the battery (2) and the second external interface (7, 8) is smaller than the maximum value of the current between the battery (2) and the first external interface (6, 8).

4. Electrical battery unit according to one of claims 1 to 3, characterized in that the switching units (4; 5) are configured to interrupt the current paths between the battery (2) and the external interfaces (6, 8; 7, 8) when predetermined threshold values ​​of the voltage of the battery (2) are undershot, and that the predetermined threshold value for interrupting the current path by the second switching unit (5) is smaller than the threshold value for interrupting the current path by the first switching unit (4).

5. Electrical energy storage system with at least one battery unit (1) according to one of claims 1 to 4, characterized in that it has an external control unit (11) connected to the internal control unit (3), by which the closing or interruption of the current path between the battery (2) and the first external interface (6, 8) can be triggered by the internal control unit (3), and that the external control unit (11) is connected to the second external interface (7, 8) of the battery unit (1) for its power supply.

6. Electrical energy storage system according to claim 5, characterized in that the external control unit (11) has a receiver for wireless reception of external signals (13), upon reception of which the external control unit (11) triggers the closure or interruption of the current path between the battery (2) and the first external interface (6, 8) by the internal control unit (3).

7. Electrical energy storage system according to claim 5 or 6, characterized in that the internal control unit (3) can be switched between a normal operating mode and a low-consumption standby mode by the external control unit (11) and that the switching can be triggered by signals (13) received wirelessly from the external control unit (11).

8. Electrical energy storage system according to one of claims 5 to 7, characterized in that the battery unit contains the battery (2), the switching units (4, 5), the internal control unit (3) and the external interfaces (6, 8; 7, 8) as components of a single assembly, and that the external control unit (11) is a separate assembly.

9. Electrical energy storage system according to one of claims 5 to 8, characterized in that a DC voltage converter (12) is connected between the battery (2) and the external control unit (11), which reduces the voltage supplied to the external control unit (11) to a value that is smaller than the value of the voltage supplied by the battery (2).

10. Electrical energy storage system according to one of claims 5 to 9, characterized in that it comprises a plurality of battery units (1) according to one of claims 1 to 3, the first external interfaces (6, 8) of which are connected in parallel and the second external interfaces (7, 8) of which are connected in parallel, and that it has a single external control unit (11) connected to the internal control units (3) of all battery units (1), which is connected to the second external interfaces (7, 8) of the battery units (1) for its power supply.

11. Electrical energy storage system according to claim 10, characterized in that a single DC voltage converter (12) is connected between the parallel connected second external interfaces (7, 8) of the battery units (1) and the external control unit (11), which supplies a lower voltage to the external control unit (11) than the voltage applied to the second external interfaces (7, 8).

12. Electrical energy storage system according to one of claims 5 to 9, characterized in that it comprises a plurality of battery units (1) according to one of claims 1 to 3, the first external interfaces (6, 8) of which are connected in series, and that it has a single external control unit (11) connected to the internal control units (3) of all battery units (1), which is connected to the second external interface (7, 8) of one of the battery units (1) for its power supply.

Images