Battery management system for battery and method for monitoring operation of battery

Abstract

The invention relates to a battery management system (20) for monitoring the operation of a battery (10) formed by electrically interconnected battery cells (12), comprising a plurality of cell monitoring units (30), each designed to generate a data packet relating to an operating state of an assigned battery cell (12), and a control device unit (40), the control device unit (40) is designed to evaluate the data packets generated by the cell monitoring unit (30), and wherein the cell monitoring unit (30) and the control device unit (40) are each provided with a radio (36, 46) and are designed to carry out a data transmission by means of the radio (36, 46), data packets generated by the cell monitoring unit (30) are transmitted from the cell monitoring unit (30) to the control device unit (40) by means of the data transmission. In order to achieve a particularly reliable and rapid transmission of data packets, the invention proposes that, for at least one of the cell monitoring units (30), a data packet generated by the cell monitoring unit (30) is transmitted to another of the cell monitoring units (30) in a first step, and in a subsequent second step, transmitting the data packet from the cell monitoring unit (30) in question to the control device unit (40). The invention also relates to a corresponding method for monitoring the operation of a battery (10).

Description

Technical Field

[0001] This invention relates to the technical field of monitoring the operation of a battery formed by electrically interconnected battery cells, and particularly to a battery management system and a corresponding monitoring method for monitoring the operation of such a battery according to the preamble of claim 1. Background Technology

[0002] The battery can be, in particular, a battery used as an energy storage device in an electric or hybrid vehicle, or a battery module of such an energy storage device (which has multiple such battery modules).

[0003] Such a battery management system—hereinafter referred to as a "BMS"—includes multiple cell monitoring units and a controller unit. The multiple cell monitoring units can be distributed across the battery, and each of the multiple cell monitoring units is electrically connected to an assigned battery cell. Each cell monitoring unit is configured to acquire at least one operating parameter (e.g., cell voltage, cell temperature, etc.) of the assigned battery cell and generate a data packet relating to the operating state of the assigned battery cell. The controller unit is configured to evaluate the data packets generated by the cell monitoring units. Each cell monitoring unit and the controller unit is equipped with a radio device and configured to perform data transmission via the radio device according to a data transmission algorithm, by means of which the data packets generated by the cell monitoring units are transmitted from the cell monitoring units to the controller unit.

[0004] Data transmission in this type of battery management system today is mostly based on the Bluetooth standard or the IEEE 802.15.4 derivative standard.

[0005] Regarding the wireless transmission of data packets, the type of battery management system referred to here is also known as "wBMS" (i.e., "wireless" BMS).

[0006] Especially in the automotive sector, it has been proven that the problems with such wBMS are that, for increasingly larger batteries, the wireless connection between the cell monitoring unit and the controller unit (“wBMS central module”) has reached its limits in terms of data rate, node latency, and download and upload throughput.

[0007] In particular, when batteries are used for large vehicles (e.g., SUVs) and commercial vehicles (e.g., trucks), the number of battery cells per battery management system is expected to increase in the future, and therefore the number of cell monitoring units (“wBMS modules”) required will also increase.

[0008] Although the cell monitoring unit or the electronic components implementing these cell monitoring units (“BMS-IC”) can be used with a larger number of acquisition channels, and thus monitor a larger number of battery cells in each case, this results in a correspondingly larger data record size for the data packets used for wireless transmission, and therefore adversely leads to a longer transmission time of the data packets to the controller unit.

[0009] Another issue is that, due to the design and installation of the cell monitoring units (mostly in complex metal structures or reflective spaces), there are often significant differences in the quality of the radio connection between the controller unit (e.g., as the "master unit") and the cell monitoring unit (e.g., as the "slave unit").

[0010] Cell monitoring units located at relatively large distances from their associated controller units and / or in unfavorable installation locations (e.g., the far side of a dual-cell layer) typically exhibit significantly poorer link budgets and lower RSSI values ​​(keyword "unreachable node"). In this context, numerous problems exist in current technologies, such as interference effects, shadowing, detuning, and multipath fading, which hinder fast and reliable data transmission. Summary of the Invention

[0011] Therefore, one object of the present invention is to indicate a novel method for monitoring the operation of a battery formed by electrically interconnected battery cells, which alleviates the thorny problems described above, and thus enables reliable and fast transmission of data packets from the cell monitoring unit to the controller unit.

[0012] According to a first aspect of the invention, this objective is achieved in a battery management system of the type mentioned at the beginning (see claim 1) by means of the following: according to a data transmission algorithm, for at least one cell monitoring unit in the cell monitoring unit, it is stipulated that a data packet generated by the cell monitoring unit is first transmitted to another cell monitoring unit in the cell monitoring unit—also referred to below as a forwarding unit—in a first step, and then the data packet is transmitted from the forwarding unit in question to the controller unit in a second step.

[0013] By using such "forwarding transmission" in the first and second steps mentioned above, data packets can be reliably transmitted to the controller unit even if the cell monitoring unit (which generates the data packets in question) is located relatively far from the controller unit or the radio connection quality between the cell monitoring unit and the controller unit is impaired due to other reasons such as shadows.

[0014] Therefore, the present invention advantageously alleviates the problems and limitations of the wireless transmission technology described above, and particularly provides a battery management system that is particularly suitable for the associated requirements, for example, when used to monitor batteries (traction batteries) used as energy storage devices or as components of such energy storage devices in electric or hybrid vehicles, due to its high throughput and still reliable data transmission.

[0015] In one embodiment of the invention, the battery has an energy storage capacity of at least 10 kWh, particularly at least 20 kWh.

[0016] In one embodiment of the forwarding transmission provided by the present invention, in the second step mentioned above, the data packet in question is directly transmitted from the forwarding unit in question to the controller unit, i.e., without the intervention of another cell monitoring unit in the cell monitoring unit as an "additional forwarding unit". However, in contrast, the present invention also provides a multi-stage forwarding transmission in this regard, wherein, in the second step mentioned above, the data packet is first transmitted from the forwarding unit in question to another cell monitoring unit in the cell monitoring unit (an additional forwarding unit), and then in the third step, the data packet is transmitted from the latter cell monitoring unit (e.g., directly) to the controller unit.

[0017] In one implementation of the data transmission algorithm, forwarding transmission using the first and second steps mentioned above is provided for at least 10% of the cell monitoring units, particularly at least 20% of the cell monitoring units.

[0018] In contrast, data packets generated by other cell monitoring units, which may be positioned relatively close to the controller unit (for example, in terms of geometry and / or radio engineering), can be directly transmitted to the controller unit in a single step. One embodiment of the invention specifies that such direct transmission is provided for at least 10%, particularly at least 20%, of the cell monitoring units, according to a data transmission algorithm.

[0019] In one implementation of the data transmission algorithm, there is a predetermined fixed allocation between these cell monitoring units, which on the one hand provide forwarding transmission using the first and second steps mentioned above, and on the other hand, forwarding units used for this purpose.

[0020] In other words, in this embodiment of the invention, the “transmission path” from each generated data packet to the controller unit is defined and fixed.

[0021] In one implementation of the data transmission algorithm, in a subsequent second step, each forwarding unit transmits the data packets received in the first step along with data packets generated by the forwarding unit itself to the controller unit.

[0022] In this case, the forwarding unit can be configured, for example, to combine a self-generated data packet with a data packet received in the first step for forwarding, to create a "combined data packet" containing information from the two data packets, and is configured to transmit the combined data packet to the controller unit in the second step (either directly to the controller unit or first to another cell monitoring unit that acts as another forwarding unit).

[0023] One implementation of the data transmission algorithm specifies that, during data transmission, the radio transmission of data packets by the cell monitoring unit—hereinafter also referred to as the uplink—is triggered each time by a corresponding requested radio reception (“polling”), wherein the requested radio transmission—hereinafter also referred to as the downlink—is preferably performed by a unit configured as the receiver of the data packets.

[0024] One implementation of the data transmission algorithm specifies that data transmission is repeated periodically, particularly for example, cyclically, wherein each data transmission is triggered by the downlink of the controller unit, and wherein, in each data transmission, all downlinks and uplinks are performed according to a transmission data frame containing multiple fixed, predetermined continuous time windows (time phases).

[0025] One particularly advantageous implementation specifies that the transmission data frames used for the downlink and uplink also provide multiple predetermined radio carrier frequencies that are different from each other for each data transmission.

[0026] The transmitted data frame may specifically provide, for example, an initial time window in which the controller unit transmits a triggered downlink on a predetermined first radio carrier frequency (first “radio frequency channel”) – also referred to below as the “main frequency” – and the cell monitoring unit addressed therefrom receives the downlink according to the data transmission algorithm.

[0027] The data frame can also provide multiple subsequent time windows (second time window, third time window, etc.) after the first time window, in which a portion of the addressed cell monitoring units utilize the controller’s uplink to respond to the downlink, so as to use each such uplink to directly transmit the data packets generated by the corresponding cell monitoring unit to the controller unit.

[0028] In the subsequent time window, the downlink can initially be initiated by another part of the addressed cell monitoring unit, namely one or more cell monitoring units acting as forwarding units, to trigger the subsequent radio transmission (uplink) of these data packets, which are then transmitted directly or indirectly to the controller unit by these forwarding units via radio transmission (uplink) in the subsequent time window after being received.

[0029] In these additional time windows, the aforementioned forwarding transmission using the first and second steps can be provided, for example, in a manner where the first step is performed in a specific time window of another time window and the second step is performed in the immediately following time window.

[0030] In one embodiment of the invention, the wireless device of the battery management system operates at a radio carrier frequency in the sub-GHz range (i.e., less than 1 GHz).

[0031] According to another aspect of the invention, the objectives mentioned at the beginning are achieved by a battery formed of electrically interconnected battery cells, the battery being equipped with a battery management system of the type described herein for monitoring the operation of the battery. Such a battery can particularly form an energy storage device or a component of such an energy storage device in an electric or hybrid vehicle.

[0032] According to another aspect of the invention, the object described at the beginning is achieved by a method for monitoring the operation of a battery formed by electrically interconnected battery cells, wherein the battery is equipped with a battery management system comprising a plurality of cell monitoring units and a controller unit, the plurality of cell monitoring units being distributed on the battery and each electrically connected to an assigned battery cell, and wherein the method comprises the following steps: - The cell monitoring unit acquires at least one operating parameter (e.g., cell voltage and / or cell temperature) of the assigned battery cell, and generates a data packet on the operating status of the assigned battery cell based on the at least one acquired operating parameter. - The data packets generated by the cell monitoring unit are evaluated using the controller unit. Data transmission is performed using a wireless device equipped in the cell monitoring unit and the controller unit according to a data transmission algorithm. Data packets generated by the cell monitoring unit are transmitted from the cell monitoring unit to the controller unit via this data transmission. Specifically, according to the data transmission algorithm, for at least one cell monitoring unit in the cell monitoring unit, the data packet generated by the cell monitoring unit is first transmitted to another cell monitoring unit in the cell monitoring unit in the first step—hereinafter referred to as the forwarding unit, and then the data packet is transmitted from the forwarding unit to the controller unit in the second step.

[0033] The embodiments and special improvements of the battery management system according to the invention described herein can also be provided, individually or in any combination, as embodiments or special improvements of the method according to the invention, and vice versa .

[0034] One embodiment of the present invention specifies that the radio device of the controller unit is formed by multiple radio transmitting and receiving units (transceiver units), which can be independently actuated by the control device of the controller unit during the operation of the BMS. The data transmission algorithm specifies that during data transmission, the multiple radio transmitting and receiving units operate at least temporarily simultaneously and at mutually different radio carrier frequencies. During data transmission, the transmitted data frames can provide one or more time windows in which multiple uplinks from mutually different cell monitoring units and / or multiple downlinks from different units (controller unit and cell monitoring unit) occur in parallel, but on mutually different radio carrier frequencies.

[0035] Another aspect of the present invention provides a computer program product comprising program code that, when executed on a data processing device, performs a method for monitoring the operation of a battery of the type described herein, formed by electrically interconnected battery cells.

[0036] Advantageously, such program code can be used in a battery management system of the type described herein to control the operation of the cell monitoring unit and the controller unit, causing the battery management system to perform a monitoring method. These mentioned units may each include, for example, a computer unit (e.g., a microcontroller) with associated storage for storing the program code.

[0037] Another aspect of the invention proposes the use of a battery management system and / or method of the type described herein for monitoring the operation of a battery arranged as an energy storage device in a vehicle (e.g., an electric or hybrid vehicle). The battery may, for example, form an energy storage device configured to supply energy to the vehicle's electric drive unit, or one of a plurality of (e.g., identically configured) battery modules of such an energy storage device. Attached Figure Description

[0038] The invention will now be described further schematically in each case with reference to the accompanying drawings, in which: Figure 1 A battery, formed of electrically interconnected battery cells and equipped with a battery management system, is shown according to a first exemplary embodiment. Figure 2 This illustrates a concept known from the prior art that can be implemented... Figure 1 The data frames used during data transmission within the battery management system. Figure 3 The configurations of the cell monitoring unit and controller unit are shown as a comparative example. Figure 4 This illustrates a concept known from the prior art. Figure 3 The transmission data frames used during data transmission in the comparison examples Figure 5 With Figure 3 The corresponding representation illustrates the configuration according to a first exemplary embodiment of the present invention. Figure 6 It is shown in accordance with Figure 5 The example data transmission uses the transport data frame. Figure 7 With Figure 3 The corresponding representation illustrates a configuration according to a second exemplary embodiment of the present invention. Figure 8 It is shown in accordance with Figure 7 The example data transmission uses the transport data frame. Figure 9 With Figure 3 The corresponding representation illustrates the configuration according to a third exemplary embodiment of the present invention. Figure 10 It is shown in accordance with Figure 9 The example data transmission uses the transport data frame, and Figure 11 A battery equipped with a battery management system according to a second exemplary embodiment is shown. Detailed Implementation

[0039] Figure 1 A first exemplary embodiment of a battery 10 configured to supply energy to an electric drive system of a vehicle, such as a battery electric vehicle (BEV) or a hybrid electric vehicle (HEV), is shown.

[0040] The battery 10 has a number of electrically interconnected rechargeable battery cells 12, which in the example shown are electrochemical battery cells 12 such as lithium-ion cells, for storing electrical energy.

[0041] The battery 10 itself can form an electrical energy storage device in the vehicle configured for the energy supply mentioned above, or the battery can be simply one of a plurality of "battery modules" of electrical energy storage devices in the vehicle, which have, for example... Figure 1 Multiple battery modules of the type shown.

[0042] Figure 1 An example of a series connection of multiple battery cells 12 is shown. Such a series connection advantageously allows the battery 10 to be supplied with a battery voltage several times higher than that of a single battery cell 12. Although for simplicity... Figure 1 As shown, in the case of battery 10 or energy storage device formed using battery 10, parallel connection of multiple battery cells 12 and / or parallel connection of multiple series-connected battery cells 12 is also advantageous in order to increase storage capacity and durability of charging or discharging battery 10 or energy storage device formed using battery.

[0043] Especially due to the application of batteries 10 in the vehicle field (e.g., in BEVs or HEVs), the highest possible energy density of energy storage is advantageous for achieving long driving ranges. However, as energy density increases, the importance of "battery management" also increases, particularly for monitoring and therefore preventing hazards related to, for example, overvoltage and overtemperature. Energy storage devices in the BEV / HEV field may include one or more batteries, for example... Figure 1 The battery 10 shown has a nominal battery voltage that is typically between 400 V and 800 V.

[0044] The battery 10 is equipped with a battery management system (BMS) 20 for monitoring the operation of the battery 10. The battery management system includes multiple cell monitoring units 30-1, 30-2, 30-3 and 30-4 and a controller unit 40. The multiple cell monitoring units are distributed on the battery 10 and are each electrically connected to the battery cell 12.

[0045] exist Figure 1 In the example shown, BMS 20 includes four cell monitoring units 30-1, 30-2, 30-3, and 30-4. More or fewer cell monitoring units may also be provided compared to this example. The reference numeral "30" is used below to refer to individual cell monitoring units or all cell monitoring units.

[0046] Each of the cell monitoring units 30 is configured to acquire at least one operating parameter (e.g., cell voltage and cell temperature) of the assigned battery cell 12 and generate a data packet about the operating status of the assigned battery cell 12.

[0047] exist Figure 1 In the schematic representation, for simplicity, only two battery cells 12 are assigned to each cell monitoring unit 30. In practice, the number of battery cells 12 assigned to each cell monitoring unit 30 can actually be significantly larger, and can be in the range of, for example, 10 to 20.

[0048] The controller unit 40 is configured to receive and evaluate data packets generated by the cell monitoring unit 30, and can be communicatively connected to the battery 10 and / or a higher-level control device of the vehicle (e.g., the vehicle's central control unit) via a data bus system (not shown). In this case, information from the received data packets and / or the derived information (regarding battery state) can be transmitted from the controller unit 40 to the higher-level control device in question.

[0049] The cell monitoring unit 30 and the controller unit 40 are each equipped with a radio device 38 (cell monitoring unit 30) or 48 (controller unit 40), and are configured to perform data transmission by means of these radio devices 38, 48, wirelessly transmitting data packets generated by the cell monitoring unit 30 from the cell monitoring unit 30 to the controller unit 40. In this example, the radio devices 38, 48 are each configured as radio transmitting and receiving devices (“transceivers”) to both transmit and receive radio transmissions and operate according to a predetermined transmission algorithm or “transmission protocol”.

[0050] In the example shown, each of the cell monitoring units 30 acquires, by means of a corresponding acquisition device 32, at least all cell voltages of the assigned battery cells 12 and one or more temperatures of the regions of these battery cells 12 as operating parameters.

[0051] Each acquisition device 32 has a method for obtaining via Figure 1 The device shown includes at least one voltage measuring device for measuring the cell voltage of the corresponding cell via the electrical connection to the assigned battery cell 12, and at least one temperature measuring device for measuring the temperature of the cell in question.

[0052] In the exemplary embodiment shown, each cell monitoring unit 30 further includes a corresponding equalization device 34, by means of which the corresponding cell monitoring unit 30 via Figure 1 The electrical connections shown to the assigned battery cells 12 are used to perform “balancing” (state of charge balancing) of the corresponding assigned battery cells 12.

[0053] In this respect, and generally advantageously for the purposes of the invention, the BMS 20 in this example not only monitors the operation of the battery 10 in a narrower sense, but also additionally provides open-loop or closed-loop control of that operation. In addition to the equalization mentioned above, this operational control also includes, for example, deactivating one or more battery cells 12 in the event of a fault (by bridging them). In energy storage systems of the type of concern herein, twelve different fault events may occur in the area where the battery cells are arranged. These events include, for example, defects in individual battery cells, whether due to aging and / or due to thermal or mechanical effects (e.g., in the case of an accident involving a vehicle in which the battery 10 is installed).

[0054] In addition, each cell monitoring unit 30 includes a program-controlled control device 36 for controlling the operation of the acquisition device 32 and the equalization unit 34 according to the control program running in the control device 36.

[0055] The program-controlled control unit 36 ​​is also used to generate data packets (data records) regarding the operating state of the allocated battery cell 12 under discussion, which are calculated by the control unit 36 ​​based on the acquired operating parameters. Each such data packet contains (digitally encoded) information about the current operating state of the battery cell 12 under discussion. For this purpose, raw data acquired, such as measurements of cell voltage and / or temperature in this example, can be provided as data elements of the data packets. Alternatively or additionally, each data packet may also advantageously contain data elements related to parameters derived from the aforementioned raw data (and calculated by the control unit 36 ​​for this purpose). One such parameter may be, for example, a parameter related to the state of charge (SOC) and / or a parameter related to (instantaneous) storage capacity, such as the "state of health" (SOH) of the battery cell 12 under discussion.

[0056] In particular, based on such preprocessing of the acquired raw data by the control device 36, in the event of an abnormal operating state of the allocated battery cell 12, the generated data packet may alternatively or additionally contain, for example, a corresponding error message, which is then transmitted to the controller unit 40.

[0057] The control device 36 also controls the operation of the radio device 38 of the cell monitoring unit 30 under discussion, i.e., actuating transmit or receive operations, and optionally predetermines the radio carrier frequency provided in this context.

[0058] The controller unit 40 further includes a program-controlled control device 46 that controls the operation of the aforementioned radio device 48 (e.g., actuation of operation to generate or receive, designation of radio carrier frequency).

[0059] The data transmission performed by the wireless devices 38 and 48 (i.e., the transmission of data packets generated by the cell monitoring unit 30 to the controller unit 40) is controlled by the control devices 36 and 46 according to the data transmission algorithm. The data transmission algorithm is defined by the program code running in the control devices 36 and 46.

[0060] As described so far, the basic concept of the BMS 20, with cell monitoring unit 30 and controller unit 40, is summarized again as follows: The primary task of each cell monitoring unit 30 is (e.g., periodically) to measure cell voltage, temperature, and optional other operating parameters. These operating parameters and / or the resulting (e.g., calculated) information are encoded into corresponding data packets by means of control device 36 and wirelessly transmitted to controller unit 40 (also referred to as the "BMS central controller") by means of radio units 38, 48. Controller unit 40 can also perform calculations, such as regarding the "state of charge" (SOC) and / or "state of health" (SOH) of battery cell 12, during the evaluation of the data packets, unless such calculations are performed via the corresponding cell monitoring unit 30 as part of (pre)processing the acquired operating parameters and the corresponding information is encoded in the data packets. Wireless data transmission of the data packets enables significant savings in cables, connectors, and, in particular, electrical isolation of components.

[0061] Figure 2 First, a "transmit data frame" 50 is shown, which can be used for... Figure 1 Data transmission within BMS 20, specifically, the transmission of data packets generated by the cell monitoring unit 30 to the controller unit 40 according to an exemplary embodiment not of this invention. In prior art wireless transmission battery management systems (“wBMS”), the required radio data transmission is performed using standard or proprietary protocols such as “Bluetooth”.

[0062] The data frame 50 is defined by the data transmission algorithm mentioned above, and further defines a specific time sequence for each radio connection or radio transmission used to implement the data transmission, which repeats periodically during the operation of the BMS 20. In this respect, data frame 50 refers to a single such data transmission.

[0063] In this example, these data transmissions are conducted at a specific radio carrier frequency (radio frequency channel). "", "", "", ",and" The radio transmissions performed on the data frame 50 are conducted in this order within five consecutive time windows and have the following meanings: Radio transmission of the request performed by controller unit 40; Radio transmission of data packets from the cell monitoring unit 30-1 to the controller unit 40; Radio transmission of data packets from the cell monitoring unit 30-2 to the controller unit 40; Radio transmission of data packets from the cell monitoring unit 30-3 to the controller unit 40; Radio transmission of data packets from the cell monitoring unit 30-4 to the controller unit 40.

[0064] symbol" " indicates "downlink", and the symbol " "Indicates uplink. Based on transmission data frame 50 ( Figure 2 During data transmission, each cell monitoring unit 30 of all cell monitoring units 30 receives via radio a request sent once per transmission data frame triggered by the controller unit 40 (downlink). To perform radio transmission of data packets (uplink) , , ,or ).

[0065] Therefore, radio communication or radio transmission on a shared radio frequency channel is hierarchically managed according to a master-slave concept, which is why the controller unit 40 is subsequently referred to as the “master unit” or “master node”, and the cell monitoring unit 30 is subsequently referred to as the “slave unit” or “slave node”.

[0066] The downlink sent by the controller unit 40 (master node) also has the following functions: signaling the start of the transmission of data frame 50 and thus timing the subsequent time window in the data frame 50 for the synchronous transmission of data frame 50 to the cell monitoring unit 30 (slave node).

[0067] For all radio transmissions during the duration of data frame 50 , , , and A specific radio carrier frequency (radio carrier channel) is provided, wherein, regarding the periodic repetition of the data transmission provided in the example, the frequency may also be changed between data transmissions (channel change) if the data transmission algorithm is so specified.

[0068] In order to perform such a channel change, the radio devices 38, 48 in question must be configured such that each radio device in the radio device can be actuated to transmit and receive on multiple different radio carrier frequencies.

[0069] Especially when applied to batteries used in the automotive industry (e.g., for large automobiles and commercial vehicles), the above reference... Figure 1 and Figure 2 The described improvements reach certain limits regarding the required performance and reliability. Depending on the specific installation of cells 30 and 40 in battery 10, the quality of the radio connection between controller unit 40 (master node) and cell monitoring unit 30 (slave node) can vary significantly. Interruptions may frequently occur if cell monitoring unit 30 is located at a distance from controller unit 40 or installed in a very unfavorable location. This is particularly true in applications where general "EMC issues" related to nearby radio transmitters come into play. In vehicle applications, potential sources of interference include, for example, other wireless communication systems (e.g., Bluetooth, Wi-Fi, mobile communications, etc.) and, for example, switch-mode inverters, DC / DC converters, etc.

[0070] This invention provides a significant improvement regarding this problem. See below for details. Figures 5 to 10 Three exemplary implementations are described below.

[0071] However, firstly, refer to Figure 3 and Figure 4 Exemplary implementations based on concepts known from the prior art will be presented again (see [link]). Figure 2 This exemplary implementation will be used as a real-world “comparative example”.

[0072] In the following description of other exemplary embodiments, the same reference numerals are used for components having the same effect. This section focuses primarily on the differences compared to the exemplary embodiments already described, and also explicitly refers to the description of the previous exemplary embodiments.

[0073] Figure 3 The configuration of a BMS 20 with 10 cell monitoring units 30-1, 30-2, ..., 30-10 and a controller unit 40 is shown as a comparative example. Figure 4 The associated transport data frame 50 used in the data transmission according to this example is shown.

[0074] As Figure 2 As in the previous example, time-division multiplexing is also used here, with each transmission passing through the "primary downlink," i.e., the radio. A new data transmission cycle is initiated, and this radio transmission contains corresponding requests (commands) to all cell monitoring units 30-1, 30-2, ..., 30-10. These communication-linked units (e.g., "pairing nodes" according to the Bluetooth standard) transmit corresponding reply radio signals, i.e., "from the uplink," at fixed time intervals, such as 2 ms (the duration of each time window). , ... and Respond.

[0075] Assuming no transmission error occurs, then therefore at the start command (radio transmission) In the 20 ms that follow, all 10 response data items from all slave nodes (data packets from units 30-1, 30-2, ..., 30-10) will be at the master node (controller unit 40): Radio transmission of the request performed by controller unit 40; Radio transmission of data packets from the cell monitoring unit 30-1 to the controller unit 40; Radio transmission of data packets from the cell monitoring unit 30-2 to the controller unit 40; ... Radio transmission of data packets from the cell monitoring unit 30-9 to the controller unit 40; Radio transmission of data packets from the cell monitoring unit 30-10 to the controller unit 40.

[0076] In summary, the transmitted data frame 50 thus comprises a total of 11 consecutive time windows, of which the last 10 time windows (each lasting 2 ms in the example) produce a “transmission duration” of 20 ms.

[0077] In this comparative example with one master node and ten slave nodes, the radio transmissions in data frame 50 are performed on radio carrier frequencies known to both the master node and the ten slave nodes (e.g., frequencies that change between data frames 50 according to a "pseudo-random sequence"). Both the radio device 48 of the controller unit 40 (master node) and the radio device 38 of the battery monitoring unit 30 (slave node) are inactive for most of the duration of data frame 50.

[0078] Frequency channel changes can occur with each transmitted data frame 50, i.e., the downlink within the same transmitted data frame 50. and the resulting uplink , ... and All operations take place on a shared radio carrier frequency. This frequency (channel) can be changed for subsequent data frames 50 transmitted in time. The resulting channel switching frequency is significantly lower than that in typical Bluetooth FHSS systems (typically 600 μs) or IEEE 802.15.4 TSCH systems (where the frequency changes in each time window).

[0079] Figure 5 An exemplary embodiment of the present invention is shown, illustrating the configuration of ten cell monitoring units 30-1, 30-2, ..., 30-10 and a controller unit 40. Figure 6 A transmission data frame 50 is shown used in data transmission according to this example of the invention. As in the comparative example ( Figure 4 In the BMS 20, during operation, data transfers, such as periodic repetitions, can be performed.

[0080] A particular feature of this exemplary implementation is that, according to a data transmission algorithm modified compared to the comparative example described above, for a plurality of cell monitoring units 30 (in the example, these cell monitoring units are four cell monitoring units 30-7, 30-8, 30-9, and 30-10), it is stipulated that, in a first step, the data packets generated by these cell monitoring units are first transmitted to another cell monitoring unit correspondingly assigned in the cell monitoring unit 30.

[0081] In this example, these cell monitoring units are four cell monitoring units 30-3, 30-4, 30-5 and 30-6, which are therefore referred to as "forwarding units" below.

[0082] In the second step only, the data packets received by the cell monitoring units 30-3, 30-4, 30-5 and 30-6 (forwarding units) in the first step are transmitted from these cell monitoring units 30-3, 30-4, 30-5 and 30-6 to the controller unit 40.

[0083] From Figure 6 The transmitted data frame 50 shown illustrates a specific implementation of this particular feature, providing a total of seven consecutive time windows with the following radio transmissions: First time window: Downlink requests made by unit 40 to units 30-1, 30-2, ..., 30-6; Second time window: , , , , Uplink from unit 30-1 (to unit 40) and downlink from units 30-3, 30-4, 30-5 and 30-6 (to units 30-7, 30-8, 30-9 and 30-10); Third time window: , , , , Uplink from unit 30-2 (to unit 40) and uplink from units 30-7, 30-8, 30-9 and 30-10 (to units 30-3, 30-4, 30-5 and 30-6); 4th time window: Uplink from unit 30-3 (to unit 40); 5th time window: Uplink from unit 30-4 (to unit 40); 6th time window: Uplink from unit 30-5 (to unit 40); 7th time window: Uplink from unit 30-6 (to unit 40).

[0084] In this example, each of the cell monitoring units 30-3, 30-4, 30-5, and 30-6, provided as forwarding units, in each case utilizes the uplink. , , , During transmission, the cell monitoring unit not only forwards a data packet (from cell monitoring units 30-7, 30-8, 30-9 and 30-10), but also forwards additional self-generated data packets (or data packets combining information from two of the data packets in question) via the same radio transmission.

[0085] In the wBMS 20 according to this embodiment, in addition to the master node (controller unit 40) and the "normal" slave nodes, namely cell monitoring units 30-1, 30-2, 30-7, 30-8, 30-9, and 30-10, there are also cell monitoring units 30-3, 30-4, 30-5, and 30-6. These cell monitoring units are referred to as "relay nodes," and these cell monitoring units also have slave functions relative to unit 40 because these cell monitoring units, upon request ( ) transmits its own (self-generated) BMS data packets to the main unit ( , , , These cell monitoring units also have master functions relative to their assigned slave units 30-7, 30-8, 30-9, and 30-10, because the latter communicate with the master unit ( , , , ) Request the transmission of data packets from the main unit ( , , , Upon receiving these data packets, the system forwards them, combined with its own data packets, to the main unit.

[0086] In data transmission, the radio transmission of data packets (uplink) performed by the cell monitoring unit 30 is triggered by a previous radio reception of a corresponding request, wherein the requested radio transmission (downlink) is performed by the unit provided as the receiver of the data packets.

[0087] For the purposes of this invention, it is preferable to provide the aforementioned forwarding transmission using the first and second steps for at least 10% of the cell monitoring units. Figure 5 and Figure 6 In the example shown, forwarding transmission is provided for four of the ten cell monitoring units 30, representing 40% of the cell monitoring units 30. Also as shown in the example, it is generally advantageous to have a predetermined, fixed allocation between these cell monitoring units 30 (here: 30-7, 30-8, 30-9, and 30-10) that provide forwarding transmission for one side and forwarding units (here: 30-3, 30-4, 30-5, and 30-6) used for the same purpose on the other side. In the example, the second step mentioned above involves transmitting data “directly” from the forwarding units to unit 40.

[0088] In the BMS 20 utilizing data transmission according to this exemplary embodiment, a "multi-channel method" is used, where multiple mutually different predetermined radio carrier frequencies are used to perform all downlink and uplink transmissions within a specific time window during each data transmission period. Simultaneous radio transmissions (i.e., radio transmissions falling within a specific time window) occur on mutually different radio carrier frequencies. Figure 6 In the representation, each "row" corresponds to a specific radio carrier frequency, which is related to... Figure 6The corresponding radio carrier frequencies of all other rows in the data frame are different. As can be seen, in this example, a total of five different frequencies are used in the data transmission frame 50; however, the specific values ​​of these frequencies can change between data transmissions, i.e., after each individual data transmission frame 50 (channel change).

[0089] Compared to wBMS known from the prior art, it offers many advantages. The wBMS or monitoring method according to the invention can be implemented particularly simply and therefore advantageously in many cases by means of firmware changes related to the program code running in known chipsets used to implement units 30, 40 (or RF modules).

[0090] exist Figure 5 In the example shown, two slave nodes (units 30-1 and 30-2) and four additional relay nodes (units 30-3, 30-4, 30-5, and 30-6) are directly connected to the master node (unit 40). The timing scheme for transmitting data frame 50 is determined here by the "master broadcast" ( ) and six reactive radio transmissions , , , , , Composition. The uplink to the master station ultimately consists only of radio transmissions from six nodes (units 30-1 to 30-6), as in this example, which may again be provided with the current (i.e., valid within the transmission data frame 50) "master station radio carrier frequency" (master frequency) known to these nodes.

[0091] exist Figure 5 In the example, each of forwarding units 30-3, 30-4, 30-5, and 30-6 has exactly one assigned (communication connection) slave node: Forwarding unit 30-3: The assigned cell monitoring unit 30-7 Forwarding unit 30-4: The assigned cell monitoring unit 30-8 Forwarding unit 30-5: The assigned cell monitoring unit 30-9 Forwarding unit 30-6: The assigned cell monitoring unit 30-10.

[0092] As shown in this example (and preferably, but not necessarily), all units 30-3, 30-4, 30-5, and 30-6 in which unit 30-1 is at the main frequency ( Within the same time frame (here: the second time window) that responds to the command broadcast, the "command broadcast" is repeated in parallel over time on four different radio carrier frequencies from the master station. These "sub-broadcasts," in this example, are downlinks performed by units 30-3, 30-4, 30-5, and 30-6. , , , It can also be staggered in time, thus... Figure 6 The example shown is different; these downlinks do not necessarily need to all occur within the same time window.

[0093] During the time window in which forwarding units (here: 30-3, 30-4, 30-5, 30-6) are transmitting their downlink, these forwarding units are inactive relative to unit 40, meaning that these forwarding units can transmit on different frequencies. Each of units 30-3, 30-4, 30-5, 30-6 uses its own frequency, which is different from both the main frequency and the frequencies of the other units 30-3, 30-4, 30-5, 30-6 (see [link to relevant documentation]). Figure 6 Symbols in different lines , (The arrangement of...). In the simplest case, each of the radio carrier frequencies of the relay units 30-3, 30-4, 30-5, and 30-6 has a separate, constant distance from the master frequency. However, more complex associated sequences can also be used (e.g., by means of a pseudo-random method), where each associated sequence is known to the unit of the communication connection. In this example, requests occurring in parallel at time (within the same time window of transmitting data frame 50) each trigger the generation of the requested data packet by the assigned slave nodes (in this example: units 30-7, 30-8, 30-9, and 30-10). The slave nodes do not communicate directly to the master node, but only directly to the "relay node".

[0094] The data is transferred from node 30-2 to the master node. In the subsequent time window, data packets from nodes (in the example: units 30-7, 30-8, 30-9, 30-10) are routed uplink from the assigned relay nodes (in the example: forwarding units 30-3, 30-4, 30-5, 30-6). , , , These transmissions are already occurring in parallel (within the same time window). These transmissions take place on the corresponding current radio carrier frequencies of the respective forwarding units 30-3, 30-4, 30-5, or 30-6.

[0095] In the four additional time windows provided in the example shown, the "combined packets" of each relay node and the assigned slave node are uploaded to the master node. , , , ).

[0096] Doubling the amount of data at the relay node would likely require a slight extension of the duration of the time window in question. At current typical physical bit rates and payload lengths, this results in an increase of approximately 0.5 ms.

[0097] Overall, such as Figure 5 The example shown is compared with the example ( Figure 4 This still results in a significant reduction of approximately 30% in the total uplink duration compared to the previous method.

[0098] Another significant advantage of the present invention is that slave nodes (e.g., more distant nodes and / or nodes obscured by installation conditions) that may be weakly connected to the master node via radio technology can be linked to the master node by means of a relay unit (relay node) with better radio connectivity.

[0099] Furthermore, increasing the number of channels per transmitted data frame by 50 (from one to five in this example) is advantageous because it more clearly reflects the basic principles of so-called "Frequency Hopping Spread Spectrum" (FHSS). The data loss caused by narrowband interference sources on the radio carrier frequency of the relay unit (relay node) is far less than that caused by interference on the main frequency, which could mean the complete loss of the transmitted data frame. In addition, the shorter duration of the transmitted data frames results in a correspondingly shorter channel occupancy time.

[0100] Figure 7 With Figure 3 or Figure 5 The corresponding illustrations show another exemplary embodiment of the present invention, illustrating the configuration of ten cell monitoring units 30-1, 30-2, ..., 30-10 and a controller unit 40, as well as... Figure 8 With Figure 4 or Figure 6 The corresponding representation shows the transmission data frame 50 used in the data transmission according to this example.

[0101] exist Figure 8 In the exemplary embodiment shown, the time required for a single data transmission is further reduced by further "clustering" the slave node to the relay node.

[0102] and Figure 6 Compared to the previous exemplary embodiments shown, Figure 8The example shown also includes relay nodes (here: units 30-4 and 30-5), each of which has multiple (here: two per relay node) assigned slave nodes, which reduces the number of relay nodes required and thus advantageously results in both a reduction in the number of mutually different radio carrier frequencies required in the transmission data frame 50 (only four in this example) and a reduction in the total uplink duration of each transmission data frame 50.

[0103] Although some adjustments to the duration of the time window must be considered in this example, since data from three packets must be transmitted within some time windows, this example is different from the comparison example ( Figure 4 Compared to the previous method, the total uplink duration was reduced by approximately 35%.

[0104] Figure 9 With Figure 3 , Figure 5 and Figure 7 The corresponding representation illustrates other exemplary embodiments of the present invention, and Figure 10 With Figure 4 , Figure 6 and Figure 8 The corresponding representation shows the transmission data frame 50 used in the data transmission.

[0105] This example illustrates an extreme but entirely realistic scenario with a configuration of 22 cell monitoring units 30-1, 30-2, ..., 30-22 and a controller unit 40 (e.g., for use in batteries in applications such as SUVs and trucks).

[0106] In this example, clustering is provided where up to five slave nodes are assigned to a relay node, which advantageously achieves the same result as the comparison example ( Figure 4 This represents a reduction of up to approximately 57% in total uplink duration.

[0107] Figure 11 Another exemplary embodiment of a battery 1 equipped with a battery management system (BMS) 20 is shown. The structure and function of the battery 1 and BMS 20 should be substantially referenced to the exemplary embodiments already described above.

[0108] However, Figure 11A particular feature of the example is that the radio device 48 of the controller unit 40 is formed by a plurality of radio transmitting and receiving units (transceiver units) 48-1, 48-2, 48-3, which can be independently actuated by the control device 46 during the operation of the BMS 20, wherein the data transmission algorithm used specifies that during data transmission, the plurality of radio transmitting and receiving units 48-1, 48-2, 48-3 operate at mutually different radio carrier frequencies (channels).

[0109] Contrary to the example shown, controller unit 40 may also use more than three or fewer than three (i.e., only two) such radio transmitting and receiving units. Specific values ​​of multiple different radio carrier frequencies can be changed between data transmissions, i.e., after each individual transmitted data frame 50 channel (channel change).

[0110] By adding additional transceivers to the master node (controller unit 40), the BMS 20 can be advantageously implemented with even a larger number of slave nodes (cell monitoring units 30), and scaled up cost-effectively. In this setup, each master transceiver unit can communicate in parallel over time with its fixed-assignment slave nodes on its own dedicated channel.

[0111] exist Figure 11 In the example, a fixed allocation can be provided as follows: radio transmitting and receiving unit 48-1 communicates with slave unit 30-1; radio transmitting and receiving unit 48-2 communicates with slave unit 30-2; and radio transmitting and receiving unit 48-3 communicates with slave units 30-3 and 30-4.

[0112] For the purposes of this invention, specific features of the plurality of radio transmitting and receiving units (48-1, 48-2, 48-3) of the controller unit (40) can preferably be specifically used to provide one or more time windows in the transmitted data frame 50 during data transmission, wherein multiple uplinks from different slave nodes proceed in parallel, but on mutually different channels (radio carrier frequencies). This enables a further significant reduction in the total uplink duration.

[0113] Figure 11 Another specific feature of the example is that the radio devices 48, 38 of the controller unit 40 and the cell monitoring unit 30 operate at a radio carrier frequency of less than 1 GHz. This enables, for example, low-interference data transmission relative to other communication systems located nearby during use (e.g., Bluetooth, mobile communications, etc.), whose bandwidth is sufficient, particularly due to the communication configuration of the present invention using a forwarding unit.

[0114] For example, Figure 11 The radio transmitting and receiving units 48-1, 48-2, and 48-3 in the examples can operate on radio carrier frequencies of 433 MHz, 868 MHz, and 915 MHz.

[0115] The advantages of radio carrier frequencies in the sub-GHz range mentioned above also apply to some extent to all the exemplary embodiments described above, making this measure universally applicable to the purposes of the present invention.

[0116] In summary, this invention enables reliable and rapid transmission of data packets from a cell monitoring unit to a controller unit during the operation of a battery formed by electrically interconnected battery cells, which can also be a module of an energy storage system formed by multiple such batteries. For this purpose, it is crucial to use a forwarding method utilizing some of the cell monitoring units present in a battery management system (BMS). In particular, further optimization can be achieved using a multi-channel forwarding method, which can achieve advantages such as: - By triggering data generation in largely parallel manner at the slave nodes (e.g., A / D conversion of measurements acquired by sensors) or generally by shortening the duration of transmitted data frames, "jitter" between acquired analog data on each channel can be reduced, and thus data quality can be improved.

[0117] - It is possible to reach severely blocked "unreachable" nodes with very poor master connectivity by means of the improved scheme according to the invention without significantly increasing the time required for data transmission.

[0118] - It can advantageously increase the spatial redundancy, temporal redundancy, and frequency redundancy of the BMS.

[0119] - By providing channel alteration, better recoverability against narrowband interference sources and malicious interference can be achieved. It also improves anti-eavesdropping capabilities.

[0120] List of reference numerals 10 batteries 12 battery cells 20 Battery Management System 30 Cell Monitoring Units 32 Acquisition Device 34 Equalization device 36 Control devices 38. Radio equipment 40 Controller Units 48. Radio equipment 50 Transmitted data frames

Claims

1. A battery management system (20) for monitoring the operation of a battery (10) formed by electrically interconnected battery cells (12), the battery management system comprising a plurality of cell monitoring units (30) and a controller unit (40), the plurality of cell monitoring units being distributed on the battery (10) and each of the plurality of cell monitoring units being electrically connected to the assigned battery cell (12). in, Each of the cell monitoring units (30) is configured to: acquire at least one operating parameter of the assigned battery cell (12), and generate a data packet related to the operating state of the assigned battery cell (12). The controller unit (40) is configured to evaluate the data packets generated by the cell monitoring unit (30). Furthermore, the cell monitoring unit (30) and the controller unit (40) are each equipped with a radio device (38, 48) and are configured to perform data transmission by means of the radio device (38, 48) according to a data transmission algorithm, wherein the data packet generated by the cell monitoring unit (30) is transmitted from the cell monitoring unit (30) to the controller unit (40) by means of the data transmission. The feature is that, according to the data transmission algorithm, for at least one of the cell monitoring units (30), it is stipulated that, in a first step, the data packet generated by the cell monitoring unit (30) is first transmitted to another cell monitoring unit in the cell monitoring unit (30) - hereinafter referred to as the forwarding unit, and then in a second step, the data packet is transmitted from the forwarding unit in question to the controller unit (40).

2. The battery management system (20) according to claim 1, wherein, According to the data transmission algorithm, at least 10% of the cell monitoring units (30), particularly at least 20% of the cell monitoring units, are provided with forwarding transmission using the first and second steps mentioned above.

3. The battery management system (20) according to any one of the preceding claims, wherein, According to the data transmission algorithm, a predetermined fixed allocation is set between these cell monitoring units (30) that provide forwarding transmission using the first and second steps mentioned above on the one hand, and forwarding units used for this purpose on the other hand.

4. The battery management system (20) according to any one of the preceding claims, wherein, According to the data transmission algorithm, in the subsequent second step, each forwarding unit will transmit the data packet received in the first step together with the data packet generated by the forwarding unit itself to the controller unit (40).

5. The battery management system (20) according to any one of the preceding claims, wherein, According to the data transmission algorithm, during the data transmission process, the radio transmission of data packets by the cell monitoring unit (30) – referred to as the uplink below – is triggered each time by a corresponding request for radio reception, wherein the requested radio transmission – referred to as the downlink below – is performed by the unit (40, 30) that is set as the receiver of the data packets.

6. The battery management system (20) according to claim 5, wherein, The data transmission algorithm specifies that data transmission is repeated periodically, wherein each data transmission is triggered by the downlink of the controller unit (40), and wherein in each data transmission, all downlinks and uplinks are executed according to a transmission data frame (50), the transmission data frame containing a plurality of fixed predetermined continuous time windows and preferably also containing a plurality of mutually different predetermined radio carrier frequencies.

7. A battery (10) consisting of electrically interconnected battery cells (12), the battery being equipped with a battery management system (20) for monitoring the operation of the battery (10) according to any one of the preceding claims.

8. A method for monitoring the operation of a battery (10) formed by electrically interconnected battery cells (12), wherein, The battery (10) is equipped with a battery management system (20), which includes multiple cell monitoring units (30) and a controller unit (40). The multiple cell monitoring units are distributed on the battery (10) and each is electrically connected to the assigned battery cell (12). The method includes the following steps: - At least one operating parameter of the allocated battery cell (12) is acquired by means of the cell monitoring unit (30), and a data packet relating to the operating state of the allocated battery cell (12) is generated by means of the cell monitoring unit (30) based on the at least one acquired operating parameter. - The data packet generated by the cell monitoring unit (30) is evaluated by means of the controller unit (40). - Data transmission is performed by means of the wireless devices (38, 48) provided by the cell monitoring unit (30) and the controller unit (40) according to the data transmission algorithm. The data packets generated by the cell monitoring unit (30) are transmitted from the cell monitoring unit (30) to the controller unit (40) by means of the data transmission. The feature is that, according to the data transmission algorithm, for at least one of the cell monitoring units (30), the data packet generated by the cell monitoring unit (30) is first transmitted to another cell monitoring unit in the cell monitoring unit (30) in a first step—hereinafter referred to as the forwarding unit, and then the data packet is transmitted from the forwarding unit in question to the controller unit (40) in a second step.

9. A battery management system according to any one of claims 1 to 5 and / or the use of the method according to claim 8 for monitoring the operation of a battery arranged as an energy storage device in a vehicle.

10. A computer program product comprising program code that, when executed on a data processing device, performs the method according to claim 8.

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