Battery system and method for operating a battery system

Abstract

Battery system (1) with at least two electrically connected battery units (10) and a battery control unit (2) for the controlled operation of the at least two battery units (10), wherein the at least two battery units (10) have a short-circuiting device (12) for short-circuiting the respective battery unit (10) and a monitoring device (13) for monitoring the respective battery unit (10), wherein the monitoring devices (13) are further supplied with electrical energy by the respective battery unit (10), characterized in that the monitoring devices (13) and the battery control unit (2) are connected in series via a bidirectional bus system (20),wherein each monitoring device (13) has a transmitting / receiving unit (15) for connection to the bus system (20), and each battery unit (10) is assigned a bridging device (30) for automatically bridging the respective transmitting / receiving unit (15) when the short-circuiting device (12) is activated.

Description

[0001] The present invention relates to a battery system according to the preamble of the independent device claim. Furthermore, the present invention is based on a method for operating a battery system according to the generic term of the independent method claim. State of the art

[0002] It is generally known from the prior art to construct battery systems from battery units connected in series and / or parallel. The battery units themselves can in turn each have one or more battery cells, which can also be connected in series and / or parallel. Battery management systems are known for monitoring, controlling, and / or regulating such battery systems. In order to provide communication between a higher-level battery control unit of such a battery management system and the individual battery units of the battery system, battery systems often have bus systems through which, in particular, bidirectional data communication can be provided between the higher-level battery control unit and the individual battery units of the battery system.

[0003] The document DE 10 2017 218 560 A1 discloses a battery unit for a battery system, comprising at least two battery cells electrically connected in parallel, a monitoring device for monitoring status data of the battery unit and a transmitting / receiving unit for data-communicating connection to a battery control device of the battery system via a bus system of the battery system.

[0004] The document DE 10 2014 215 773 A1 discloses a method for operating a battery system with a plurality of battery cells and a battery management system for monitoring and controlling the battery cells, wherein the battery management system has a main control device and a plurality of cell control units, wherein each cell control unit is assigned to a battery cell and is designed and configured to acquire measurement data of the assigned battery cell and to connect and disconnect the assigned battery cell to an electronic circuit of the battery cells. Disclosure of the invention

[0005] The subject matter of the invention is a battery system having the features of the independent device claim and a method for operating a battery system having the features of the independent method claim. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the battery system according to the invention naturally also apply in connection with the method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0006] According to a first aspect, the present invention relates to a battery system having at least two electrically connected battery units and a battery control unit for the controlled operation of the at least two battery units, wherein the at least two battery units have a short-circuiting device for short-circuiting the respective battery unit and a monitoring device for monitoring the respective battery unit, wherein the monitoring devices can further be supplied with electrical energy by the respective battery unit.A battery system according to the invention is characterized in that the monitoring devices and the battery control unit are serially connected via a bidirectional bus system, wherein each monitoring device has a transmitting / receiving unit for connection to the bus system, and each battery unit is assigned a bridging device for automatically bridging the respective transmitting / receiving unit when the short-circuiting device is active. This enables safe operation of the entire battery system, even if a battery unit becomes defective or deactivated.

[0007] A battery system according to the invention is constructed from at least two battery units that are electrically interconnected. The individual battery units can in turn each have one or more battery cells that are also electrically interconnected. In particular, the individual battery units or the individual battery cells can be designed as lithium-ion cells. A battery management system, in particular provided as the main component by the battery control unit, is provided for controlled operation, in other words, monitoring, controlling and / or regulating the battery system. Each battery unit in turn has a short-circuiting device by which the respective battery unit can be short-circuited in an emergency, e.g., an overload and / or a mechanical defect in the battery unit.This short-circuiting can, in most cases, prevent major damage to the individual battery unit and, in particular, to the entire battery system. A monitoring device also monitors each battery unit, with the electrical energy required to operate the monitoring device being provided by the monitored battery unit itself. The monitoring results from the monitoring device can also be forwarded, for example, to the higher-level battery control unit.

[0008] For this transmission of the monitoring results, the invention provides a particularly bidirectional bus system, via which the individual battery units, in particular the monitoring devices of the individual battery units, are serially connected. For this purpose, each of the monitoring devices can have a transmitting / receiving unit for connection to the serial bus system. In particular, a battery system according to the invention can be designed such that the serial bus is not designed as a continuous bus, but rather that the transmitting / receiving units in the individual battery units each represent an interruption in the bus system.Data transported via the bus system is received in each battery control unit in this embodiment by the transmitting / receiving unit at an input connected to the bus system, processed in the transmitting / receiving unit, and retransmitted at an output also connected to the bus system. This can, for example, ensure that data signals in the bus system have a particularly high signal quality. This can be made possible in particular by checking the data quality in each transmitting / receiving unit used and improving and / or amplified if necessary. This enables particularly robust and secure data transmission via the serial bus system used, especially over long distances.

[0009] If a short-circuiting device of the battery unit is triggered, the respective battery unit is short-circuited and can no longer provide electrical energy, in particular also not for operating the monitoring device, and thus also the associated transmitting / receiving unit of the corresponding battery unit. In order to prevent an interruption of data communication via the bus system when a short-circuiting device of the battery unit is triggered, a battery system according to the invention essentially comprises a bridging device. Such a bridging device is designed in particular to bridge the respective transmitting / receiving unit, wherein this bridging occurs automatically, in particular when the short-circuiting device is activated. Bridging within the meaning of the invention can in particular represent an electrically conductive connection of the input and the output of the transmitting / receiving unit.Data communication, which occurs in particular via electrical impulses via the bus system, can thus be ensured even with a monitoring device without electrical power. Automatic, in the sense of the invention, can mean, in particular, that the bridging of the transmitting / receiving unit is triggered solely by activation of the short-circuiting device, in particular without external triggering and / or without the need for additional sensors or evaluation elements.

[0010] In summary, the elements of a battery system according to the invention, in particular the bridging device, enable the use of a serial bus system with transmitting / receiving units for a battery system, wherein, in particular, an interruption of data communication via the bus system is prevented in the event of a failure of one of the battery units. The advantages of a serial bus system with transmitting / receiving units can thus also be provided for battery systems whose battery units have short-circuiting devices. Operation of the entire battery system or the battery management system can be ensured even if one or more short-circuiting devices are triggered, which can, in particular, increase overall reliability during operation of the battery system.

[0011] Furthermore, in a battery system according to the invention, it can be provided that the bridging device comprises a transistor element, preferably a junction field-effect transistor, and / or an electromechanical switch element. These particularly preferred embodiments enable automation in the provision of the bridging functionality in a particularly simple manner. A transistor element, particularly a junction field-effect transistor, can electronically provide the ability to bypass a transmitting / receiving unit. For this purpose, the transistor element is constructed such that it is automatically switched on if an electrical power supply to the monitoring device is lost. An electromechanical switch element can be constructed in a similarly simple manner, for example, having a switch section that is held in the open position by an electromagnet.If the power supply to the monitoring device is lost, the power supply to the electromagnet is also automatically lost, and the electromagnetic switch element closes. In both cases, it is particularly easy to ensure that the bridging device automatically bypasses the transmitting / receiving unit in the event of a triggered short-circuit device.

[0012] In a battery system according to the invention, it can also be provided that the bridging device is designed as an integrated part of the monitoring device. In this embodiment, a particularly compact design of the bridging device can be provided. For example, the bridging device can be arranged on the same circuit board as the monitoring device and / or even programmed or implemented in the same chip element as the monitoring device. This particularly compact embodiment also enables, in particular, a particularly compact battery system overall, so that, for example, a higher electrical power can be provided by the battery system according to the invention with the same volume.

[0013] Alternatively, in a battery system according to the invention, the bridging device can be designed as an external part that is structurally separate from the monitoring device. This represents a particularly flexible embodiment of a battery system according to the invention, since an arrangement of the bridging device is not coupled to the actual monitoring device, and thus spatial arrangements of the bridging device in relation to the monitoring device that can be adapted to particularly diverse requirements can be provided. In particular, this embodiment also allows for the retrofitting of an existing battery system or the monitoring devices of the individual battery units with bridging devices.

[0014] Furthermore, a battery system according to the invention can be configured such that the at least two battery units each comprise a battery cell and / or a group of battery cells connected in series or in parallel. In this way, the individual battery units can meet a wide variety of requirement profiles. For example, by connecting the battery cells in series, the individual battery units can provide a higher voltage, while by connecting the battery cells in parallel, they can provide a higher current. This allows the entire battery system to be adapted to a wide variety of requirements with regard to the electrical parameters to be provided.

[0015] A battery system according to the invention can also be further developed such that the at least two battery units are electrically connected in series and / or in parallel. This embodiment also enables a further increase in flexibility in the design and / or planning of a battery system according to the invention. Thus, the serial connection of two battery units can also increase the overall voltage that can be provided by the battery system. By connecting the at least two battery units in parallel, an increase in the electrical current that can be provided is possible. Overall, a battery system according to the invention can thus be designed to meet a wide variety of requirements with regard to the electrical parameters to be provided.

[0016] Furthermore, a battery system according to the invention can be designed such that the bus system is configured as a serially cascaded bus, preferably as a differential two-wire bus. Such a serially cascaded bus, often also referred to as a daisy-chain bus, can provide a particularly robust and secure bus system design for a battery system according to the invention. In a differential two-wire bus, the electrical data is additionally transmitted as a voltage difference between the two wires of the two-wire bus. This enables even more secure data transmission.

[0017] Furthermore, in a battery system according to the invention, it can be provided that the monitoring device has at least one sensor element for determining data from at least one of the following state variables of the respective battery unit: - Tension, - Electricity, - temperature, - Pressure

[0018] The above list is not exhaustive, so that sensor elements can also be connected to a monitoring device of a battery system according to the invention for determining additional data. Overall, a monitoring device can thus provide comprehensive monitoring of state variables of the individual battery units or the battery cells of the individual battery units of a battery system according to the invention.

[0019] According to a second aspect of the invention, the object is achieved by a method for operating a battery system according to the first aspect of the invention. A method according to the invention is characterized in that, upon activation of a short-circuiting device of one of the battery units, the bridging device of the respective battery unit is automatically and simultaneously or at least substantially simultaneously activated.

[0020] A method according to the invention is designed for operating a battery system according to the first aspect of the invention. As a result, the same advantages that have already been described in detail with regard to a battery system according to the first aspect of the invention can be provided by a method according to the invention. In particular, according to a method according to the invention, upon activation of a short-circuiting device, the bus system of the battery system in the corresponding battery unit can be automatically bridged. This is done in particular by the bridging device of the respective battery unit, which is activated automatically and simultaneously or at least essentially simultaneously. This ensures, in particular preferably without a time delay, that communication via the bus system is maintained, which without the bridging device would be interrupted by the failure of the corresponding transmitting / receiving unit.Overall, a method according to the invention can thus ensure that communication via the bus system of the battery system is possible at all times, in particular regardless of whether a short-circuiting device is activated in one of the battery units or not.

[0021] A method according to the invention can be designed such that activation of a bridging device of a battery unit by the battery control unit is detected by detecting a reduced electrical voltage and by detecting a lack of data from the respective battery unit. By bridging the de-energized transmitting / receiving unit in the battery unit with an activated short-circuiting device, the short-circuiting device cannot be activated by interrupting data communication via the bus system. However, when the short-circuiting device is activated, the corresponding battery unit no longer contributes any voltage to the overall voltage of the battery system. This can be noticed by detecting a reduced electrical voltage, whereby activation of a bridging device of the corresponding battery unit can be indirectly detected.The absence of typically transmitted data, for example, the continuous monitoring of a voltage and / or current of the respective battery unit, can also indicate the activation of a bridging device of the respective battery unit. Overall, a method according to the invention in a battery system according to the invention can thus reliably detect the activation of a bridging device and thus the activation of a short-circuiting device, and in particular, also identify the battery unit with the activated short-circuiting device.

[0022] Further advantages, features, and details of the invention will become apparent from the following description, which describes an embodiment of the invention in detail with reference to the drawing. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination.

[0023] It shows: Fig. 1 a battery system according to the invention.

[0024] Fig.1 shows a battery system 1 according to the invention, of which two identical battery units 10 are shown in particular. A higher-level battery control unit 2 is provided for monitoring, controlling, and / or regulating the individual battery units 10 and is connected to the individual battery units 10 via a bus system 20, which can be designed, for example, as a serially cascaded bus. For this purpose, the individual battery units 10 each have a transmitting / receiving unit 15, which can be supplied with electrical energy directly from the respective battery unit 10 via a power supply 16. The transmitting / receiving units 15 are part of a monitoring device 13 provided in each battery unit 10. Part of the monitoring device 13 can also be, for example, sensor elements 14, which are designed to monitor operating variables of the individual battery units 10, for example a voltage and / or a current of the respective battery cell 11.Insulations 21 between the individual battery units 10 and the bus system 20 enable a voltage shift of the bus signal. Furthermore, these insulations 21 can prevent the transmission of electrical energy from the individual battery cells 11 of a battery unit 10 via the bus system 20 in the event of a defect.

[0025] A single battery cell 11 is shown in each of the individual battery units 10. Battery units 10 according to the invention can also have a plurality of battery cells 11, which can be electrically connected in series or in parallel. Furthermore, the illustrated battery units 10 are electrically connected in series, which can, for example, increase the overall voltage of the battery system 1. Each battery cell 11, which can in particular be a lithium-ion cell, further has a short-circuiting device 12. In the event of a defect in the battery cell 11, this short-circuiting device 12 automatically short-circuits the corresponding battery cell 11, thereby preventing major damage to the battery unit 10 or the entire battery system 1. In this case, however, the power supply 16 also fails, so that the monitoring device 13 is de-energized.In order to maintain communication via the bus system 20, a battery system 1 according to the invention essentially comprises a bridging device 30. The respective bridging device 30 can, as shown, be designed as an integral part of the respective monitoring device 13. Alternatively, the bridging device 30 of a battery unit 10 can also be designed as a separate part from the respective monitoring device 13. This bridging device 13 is closed automatically and simultaneously and / or at least substantially simultaneously in the event of activation of a short-circuiting device 12.This bypasses the transmitting / receiving unit 15, which would block communication via the bus system 20 when de-energized, so that the remaining, preferably still functioning, battery units 10 of the battery system 1 can continue to be addressed by the battery control unit 2 via the bus system 20. A failure of a battery unit 10, such as occurs when the short-circuiting device 12 is activated, can be detected, for example, by a reduced overall voltage of the battery system 1 and / or by the absence of data from the corresponding battery unit 10.

[0026] In summary, a battery system 1 according to the invention can thus provide that data communication between the individual battery units 10 can take place via a serial bus system 20, without having to fear an interruption in the data communication in the event of activation of a short-circuiting device 12 in one of the battery units 10. Use of a serial bus system 20 can thus also be provided in battery systems 1 whose battery units 10 have short-circuiting devices 12.

Claims

[1] Battery system (1) with at least two electrically connected battery units (10) and a battery control unit (2) for the controlled operation of the at least two battery units (10), wherein the at least two battery units (10) have a short-circuiting device (12) for short-circuiting the respective battery unit (10) and a monitoring device (13) for monitoring the respective battery unit (10), wherein the monitoring devices (13) are further supplied with electrical energy by the respective battery unit (10), characterized byin that the monitoring devices (13) and the battery control unit (2) are connected in series via a bidirectional bus system (20), wherein each monitoring device (13) has a transmitting / receiving unit (15) for connection to the bus system (20) and each battery unit (10) is assigned a bridging device (30) for automatically bridging the respective transmitting / receiving unit (15) when the short-circuiting device (12) is activated. [2] Battery system (1) according to claim 1, characterized by that the bridging device (30) comprises a transistor element, preferably a junction field effect transistor, and / or an electromechanical switch element. [3] Battery system (1) according to claim 1 or 2, characterized by that the bridging device (30) is designed as an integrated part of the monitoring device (13). [4] Battery system (1) according to claim 1 or 2, characterized bythat the bridging device (30) is designed as an external part structurally separate from the monitoring device (13). [5] Battery system (1) according to one of the preceding claims, characterized by that the at least two battery units (10) are each a battery cell (11) and / or a group of battery cells (11) connected in series or in parallel. [6] Battery system (1) according to one of the preceding claims, characterized by that the at least two battery units (10) are electrically connected in series and / or parallel. [7] Battery system (1) according to one of the preceding claims, characterized by that the bus system (20) is designed as a serially cascaded bus, preferably as a differential two-wire bus. [8] Battery system (1) according to one of the preceding claims, characterized bythat the monitoring device (13) has at least one sensor element (14) for determining data of at least one of the following state variables of the respective battery unit (10): - Tension - Electricity - Temperature - Pressure [9] Method for operating a battery system (1) according to one of the preceding claims, characterized by that when a short-circuiting device (12) of one of the battery units (10) is activated, the bridging device (30) of the respective battery unit (10) is activated automatically and simultaneously or at least substantially simultaneously. [10] Method according to claim 9, characterized bythat activation of a bridging device (30) of a battery unit (10) by the battery control unit (2) is detected by detecting a reduced electrical voltage and / or by detecting a lack of data from the respective battery unit (10).

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