TECHNICAL FIELD

The invention concerns in general the technical field of battery packs. More par- ticularly, the invention relates to a solution for determining a configuration of the battery pack.

BACKGROUND

Today electrical energy storage solutions are brought in various application ar eas in addition to ones already know. For example, vehicles are equipped with batteries for supplying electrical energy to an electric motor residing in the vehi cle. Moreover, other entities, such as buildings, may be equipped with batteries which may be taken into use if a power failure occurs. The battery solutions nowadays are usually established as battery packs comprising a plurality of bat tery cells included in a space, such as in a housing. The battery cells are typically identical arranged in series or parallel or in any mixture of both to provide desired voltage in the application area. In order to control the battery pack a control unit may be arranged in the battery pack for enabling a battery management.

Identification of the battery cells within the battery pack is required in various situation. Especially, in a situation where it is recognized, in one manner or other, that a performance of at least one battery cell is degraded it is important to iden tify the one or more battery cells not operating properly. The identification com prises, among others, a determination of a position of the battery cell in the bat tery pack. By determining the position of the battery cell in question it is possible to take maintenance actions in efficient manner with respect to battery cell not operating properly.

In a prior art document US 9586541 B2 it is disclosed one solution for identifying a particular battery cell within an application. The solution is based on a resistor divider network in which by measuring voltages in between resistors of the re sistor divider network associated with the battery cells, and based on voltage variation between the measurement points it is possible to identify each cell uniquely. The existing solutions are applicable as such, but alternative solutions may be developed which improve, at least in part, a determination of a position of battery cells in the battery pack structure.

SUMMARY

The following presents a simplified summary in order to provide basic under- standing of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying em- bodiments of the invention.

An object of the invention is to present a computer implemented method, a con trol unit and a computer program for determining a configuration of a battery pack.

The objects of the invention are reached by a computer implemented method, a control unit and a computer program as defined by the respective independent claims.

According to a first aspect, a computer implemented method for determining a configuration of a battery pack comprising a plurality of battery modules opera tionally connected as a string of battery modules is provided, wherein a battery module comprises a radio frequency identification, RFID, reader configured to read a radio frequency identification, RFID, tag of an adjacent battery module, the method comprising: receiving first data from a first battery module, wherein the first data comprises module identifier of the first battery module associated with second data of a second battery module adjacent to the first battery module, the second data comprising at least module identifier of the second battery mod ule; and determining the configuration of the battery pack based on the first and second data. The method may further comprise: receiving data indicating a number of the battery modules belonging to the battery pack; and determining the configuration of the battery pack using the data indicating the number of the battery modules belonging to the battery pack.

For example, the configuration of the battery pack may be determined by de- tecting an identifier of a frame tag as the second data received from the first battery module and applying a known position of the frame tag in the configura tion of the battery pack in the determination.

Further, the configuration of the battery pack may be determined by detecting an identifier of a RFID control reader as the first data and applying a known position of the RFID control reader in the configuration of the battery pack in the determination.

The data received from the first battery module may comprise further data com prising at least one further identifier received from at least one further battery module. The configuration of the battery pack may be determined by detecting an iden tifier of the RFID control reader as the first data, and by detecting an identifier of a frame tag as the second data received from a battery module of the string of battery module. For example, the method may further comprise: determining data indicating a number of the battery modules belonging to the string of battery modules. The configuration of the battery pack may be determined by applying the data indicating the number of the battery modules in the determination. The battery pack may comprise the string of battery modules.

Generally speaking, the battery module may correspond to the battery cell. Alternatively or in addition, the battery pack may correspond to the battery mod ule.

According to a second aspect, a control unit for determining a configuration of a battery pack comprising a plurality of battery modules operationally connected as a string of battery modules is provided, wherein a battery module comprises a radio frequency identification, RFID, reader configured to read a radio fre quency identification, RFID, tag of an adjacent battery module, the control unit comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code config- ured to, with the at least one processor, cause the control unit to: receive first data from a first battery module, wherein the first data comprises module identi fier of the first battery module associated with second data of a second battery module adjacent to the first battery module, the second data comprising at least module identifier of the second battery module; and determine the configuration of the battery pack based on the first and second data.

The control unit may further be configured to: receive data indicating a number of the battery modules belonging to the battery pack; and determine the config uration of the battery pack using the data indicating the number of the battery modules belonging to the battery pack. The control unit may also be configured to determine the configuration of the battery pack by detecting an identifier of a frame tag as the second data received from the first battery module and applying a known position of the frame tag in the configuration of the battery pack in the determination.

Still further, the control unit may be configured to determine the configuration of the battery pack by detecting an identifier of a RFID control reader as the first data and applying a known position of the RFID control reader in the configura tion of the battery pack in the determination. Moreover, the control unit may be configured to receive further data from the first battery module, the further data comprising at least one further identifier received from at least one further battery module.

The control unit may further comprise a RFID control reader, wherein the control unit may be configured to determine the configuration of the battery pack by detecting an identifier of the RFID control reader as the first data, and by detect ing an identifier of a frame tag as the second data received from a battery mod ule of the string of battery modules. The control unit may also be configured to determine data indicating a number of the battery modules belonging to the string of battery modules. For example, the control unit may be configured to determine the configuration of the battery pack by applying the data indicating the number of the battery modules in the determination.

The battery pack may comprise the string of battery modules.

According to a third aspect, a computer program embodied on a computer read- able medium comprising computer executable program code is provided, which code, when executed by at least one processor of a control unit, causes the control unit to: receive first data from a first battery module, wherein the first data comprises module identifier of the first battery module associated with second data of a second battery module adjacent to the first battery module, the second data comprising at least module identifier of the second battery module; and determine the configuration of the battery pack based on the first and second data.

The expression "a number of refers herein to any positive integer starting from one, e.g. to one, two, or three. The expression "a plurality of refers herein to any positive integer starting from two, e.g. to two, three, or four.

Various exemplifying and non-limiting embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying and non-limiting embodiments when read in connection with the accompanying drawings.

The verbs“to comprise” and“to include” are used in this document as open limitations that neither exclude nor require the existence of unrecited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of“a” or“an”, i.e. a singular form, throughout this document does not exclude a plural ity. BRIEF DESCRIPTION OF FIGURES

The embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.

Figure 1 illustrates schematically an example of a battery pack.

Figure 2 illustrates schematically a system according to an example embodi- ment.

Figure 3 illustrates schematically a control unit according to an example embod iment.

Figure 4 illustrates schematically a method according to an example embodi ment. Figure 5 illustrates schematically aspects relating to a determination of a config uration according to an example embodiment.

Figures 6A-6E illustrates schematically further aspects relating to a determina tion of a configuration according to an example embodiment.

Figure 7 illustrates schematically a RFID module according to an example em- bodiment. DESCRIPTION OF THE EXEMPLIFYING EMBODIMENTS

The specific examples provided in the description given below should not be construed as limiting the scope and/or the applicability of the appended claims. Lists and groups of examples provided in the description given below are not exhaustive unless otherwise explicitly stated.

To operate an electric vehicle, such as a marine vessel, an enormous amount of power is required. That is why electric vehicles, such as marine vessels or power plants with balancing backup, need as many as tens of thousands of bat tery cells. The composition of a battery might vary slightly depending on the types of electric vehicles, but generally electric vehicle batteries could be con figured to be composed of cells, modules and a pack.

In fact, to safely and efficiently manage the countless battery cells mounted in one vehicle, such as marine vessel, the cells are installed in forms of modules and packs. Simply put, cells, modules and packs are units of gathered batteries. A cluster of cells make up a module and a cluster of modules make up a battery pack. Ultimately, in an electric vehicle, one form of battery is installed: a battery pack.

A cell is understood to be the basis of a battery that must possess high capacity per unit volume in order to show maximum performance in a restricted area within a vehicle or power plant and the cell also needs to have much longer lifespan compared to batteries used in consumer mobile devices. Thus cell-level identification and service are more important in vessels and power plants than in consumer products, for example. Furthermore, cells must endure shocks transmitted during the drive and possess high reliability & stability to the extent of being able to withstand high and low temperatures.

When a number of cells are put into a frame to protect them better from external shocks such as heat or vibration, this may be called as a battery module. And when a number of battery modules come together with a BMS (Battery Management System) and a cooling device that control and manage battery’s temperature, voltage, etc., this may be called as a battery pack. This is how numerous cells are installed in an electric vehicle through the form of a pack.

The above described concepts are schematically illustrated in Figure 1 in which a battery pack 100 comprises a plurality of battery modules 120 each comprising a number of battery cells 110. The configuration schematically depicted in Figure 1 is a non-limiting example and the configuration may vary a lot. For example, the battery pack 100 may comprise only one battery cell 110 which means that the battery pack 100 corresponds to the battery module 120 and the battery module 120 corresponds to the battery cell 110 with the definitions as described. As also derivable from Figure 1 , each battery module 120 may comprise a vari ous number of battery cells 110.

For a purpose to describe at least some aspects of the invention the Figure 2 is referred to. Figure 2 illustrates schematically a system according to an example embodiment as a block diagram. The system according to the example may comprise a battery module 120 consisting of a plurality of battery cells 110 and a control unit 150. The battery module 120 may be implemented as a housing for a number of battery cells 110. At least some of the plurality of the battery cells 110 are equipped with a communication device suitable for a short range communication. For sake of clarity, the communication device in a context of the present invention may e.g. be a RFID (Radio Frequency Identification) module comprising a RFID tag 115 and a RFID reader 114. The RFID tag 115 may comprise electronically stored information, such as an identifier of the RFID tag 115 in question. The information is readable with a RFID reader 114 which may send a signal to the RFID tag 115 and read its response. In the described man ner it is possible e.g. to identify an entity into which the RFID module is mounted to. Flence, in an implementation as illustrated in Figure 2 the RFID module of a battery cell 110 may communicate with at least one other RFID module of an other battery cell 110. Still further, the RFID modules, and specially the reader portion 114 therein, may be arranged to communicate with the control unit 150 either directly or indirectly. The direct communication may e.g. be implemented with a wired or wireless communication interface implemented both in each RFID reader 114 and the control unit 150. The indirect communication, in turn, may be implemented by arranging one RFID module to communicate with the control unit 150 through at least one other RFID module. Some non-limiting ex amples of an implantation utilizing a wired communication may be such that a data bus, such as a CAN bus, is arranged between the control unit 150 and the RFID readers 114. Alternatively or in addition, a power line connecting e.g. the batteries and the control unit 150 may be used. In such an implementation, the RFID module, and especially the RFID reader 114 is equipped with an applica ble interface to access the power line. On the other hand, the wireless commu nication may be implemented with any known short range communication pro tocol or a dedicated wireless communication implementation by arranging nec essary devices and interfaces to the communicating entities. As mentioned, in various embodiments the battery cells 110 may be arranged as battery modules 120, the battery modules 120 each comprising a number of battery cells 110. In such an embodiment the RFID module may be arranged to each battery module for identifying a number of battery cells 110 arranged in the module in question. Correspondingly, the battery modules 120 may form a sub- system in which is battery cell 110 is equipped with RFID module wherein each battery module 120 is further equipped with a control unit 150 corresponding the one as described in the context of Figure 1. One of the control units 150, or a separate control unit 150, may be arranged to operate as a master control unit for communicating and operating as is described herein. As discussed above, the system may comprise a control unit 150 for communi cating with the RFID modules as well as for processing of data. Figure 3 illus trates schematically as a block diagram an example of the control unit 150 ap plicable in the battery pack 100. The block diagram of Figure 3 depicts some components of an apparatus that may be employed to implement the control unit 150. The apparatus comprises a processor 210 and a memory 220. The memory 220 may store data and computer program code 225. The apparatus may further comprise communication means 230 for wired or wireless commu nication with other apparatuses and/or user I/O (input/output) components 240 that may be arranged, together with the processor 210 and a portion of the com- puter program code 225, to provide the user interface for receiving input from a user and/or providing output to the user. In particular, the user I/O components may include user input means, such as one or more keys or buttons, a keyboard, a touchscreen or a touchpad, etc. The user I/O components may include output means, such as a display or a touchscreen. The components of the apparatus may be communicatively coupled to each other via a bus 250 that enables trans fer of data and control information between the components.

The memory 220 and a portion of the computer program code 225 stored therein may be further arranged, with the processor 210, to cause the apparatus, i.e. the control unit 150, to perform a method as will be described in a forthcoming description. The processor 210 may be configured to read from and write to the memory 220. Although the processor 210 is depicted as a respective single component, it may be implemented as respective one or more separate pro cessing components. Similarly, although the memory 220 is depicted as a re spective single component, it may be implemented as respective one or more separate components, some or all of which may be integrated/removable and/or may provide permanent / semi-permanent/ dynamic/cached storage.

The computer program code 225 may comprise computer-executable instruc tions that implement functions that correspond to steps of the method as will be described when loaded into the processor 210. As an example, the computer program code 225 may include a computer program consisting of one or more sequences of one or more instructions. The processor 210 is able to load and execute the computer program by reading the one or more sequences of one or more instructions included therein from the memory 220. The one or more se quences of one or more instructions may be configured to, when executed by the processor 210, cause the apparatus to perform the method will be described. Hence, the apparatus may comprise at least one processor 210 and at least one memory 220 including the computer program code 225 for one or more pro grams, the at least one memory 220 and the computer program code 225 con figured to, with the at least one processor 210, cause the apparatus to perform the method described in the foregoing.

The computer program code 225 may be provided e.g. a computer program product comprising at least one computer-readable non-transitory medium hav ing the computer program code 225 stored thereon, which computer program code 225, when executed by the processor 210 causes the apparatus to perform the method. The computer-readable non-transitory medium may comprise a memory device or a record medium such as a CD-ROM, a DVD, a Blu-ray disc or another article of manufacture that tangibly embodies the computer program. As another example, the computer program may be provided as a signal config ured to reliably transfer the computer program. Still further, the computer program code 225 may comprise a proprietary appli cation, such as computer program code for battery management. The proprie tary application may be a client application of a service whose server application is running on a server apparatus of the system. The proprietary application may detect an anomaly within the battery pack 100, identify the battery cell 110, or a battery module 120, that the anomaly is related to, and automatically generate a service task associated information of the anomaly and the location of the battery cell 110 using the automatic battery location configuration.

Any of the programmed functions mentioned may also be performed in firmware or hardware adapted to or programmed to perform the necessary tasks. The control unit 150 as described may be arranged to perform its task with re spect to one or more battery modules 120 each comprising one or more battery cells 110. Next, a method in accordance with an example embodiment of the invention is described by referring to Figure 4 for automatically determining a configuration of battery pack 100. A step 310 as illustrated in the Figure 4 may be performed by one or more RFID modules and an aim of the step 310 is to establish a nec- essary amount of information for performing the method in accordance with the example embodiment of the invention. In the mentioned step a plurality of RFID modules associated with battery cells 110 of the battery pack 100 are arranged to communicate with each other. The communication may e.g. be initiated with a trigger signal generated by the control unit 150 to the RFID modules of the battery cells 110. Depending on a type of RFID modules, and especially the RFID tags 115 therein, a receipt of the trigger signal by the RFID reader 114 of the RFID module may cause at least one of the following. Either the RFID reader 114 may generate a radio signal to activate at least one RFID tag 115 to transmit information to the RFID reader 114. Alternatively, the receipt of the trigger signal may cause the RFID reader 114 to obtain data carried in a signal generated by the RFID tag 115. The above described alternative mechanisms are dependent on if the RFID tag 115 of the RFID module is passive (RFID tag 115 becomes active in response to an interrogating radio wave) or active (RFID tag 115 equipped with a power source). Flence, in step 310 the RFID reader 114 of a first RFID module may be arranged to communicate with a RFID tag 115 of at least one second RFID module. In the communication the RFID reader 114 of the first RFID module may receive at least an identifier transmitted by the RFID tag 114 of the at least one second RFID module, the identifier representing the battery module 120 into which the RFID tag 115 of the at least one second RFID module is associated to. Flence, the RFID reader 114 of the first RFID module receives an identifier representing the battery module 120 belonging to the bat tery pack 100, such as a neighboring battery module 120, and the RFID reader 114 in question may be configured to associate its own identifier representing the identifier of a battery module 120 with the at least one identifier representing the identifier of a second battery module 120 received from the RFID tag 115 of the at least one second RFID module. The own module identifier may be called as a first data and the other module identifier may be called as the second data. The association of the identifiers may be performed in any manner by means of which pieces of data may be combined together, such as by including them in a same data record in a predetermined manner. As a result, the RFID reader 114 of the first battery module 120 may possess first data comprising an identifier of the battery module 120 into which the RFID module 115 is associated to and at least one other second data comprising another identifier of at least one other battery module 110. In response to the described operation the RFID module possessing the data may be arranged to transmit the data to the control unit 150 by generating a signal over a predefined communication channel to the control unit 150.

Flence, the control unit 150 may be arranged, in step 320 as illustrated in Figure 4, to receive signal carrying the first data and the second as described from a plurality of RFID modules. In response to a receipt of data the control unit 150, specifically the processor by executing a computer program code, may be caused to start determining 330 a configuration of the battery pack 100. The determination of the configuration may be performed by establishing a model of the configuration of the battery pack 100 comprising a plurality of the battery modules 120 based on the data received from the plurality of the battery mod- ules 120. The model may be established for generating a representation of mu tual positions of the battery modules 120 in the battery pack 100. The establish ment of the model may be performed by analyzing identifiers included in the received data i.e. represented by the first data and the second data. The analy sis may e.g. be performed so that a first battery module 120 is determined on a basis of an identifier included in the first data. One or more other identifiers are also identified from the second pieces of data received by the control unit 150. Next, a second battery module 120 is determined on a basis of another identifier included in the second data. The operation described above is performed with respect to all battery modules 120 from which the data is received by the control unit 150. Next, the control unit 150 may be arranged to compare if the data re ceived from the plurality of battery modules 120 comprise any same identifiers. Based on detections of the same identifier in data received from a plurality of battery modules 120 it may be concluded that the battery modules 120 are neighboring ones. In such a manner it is possible to establish a chain of the battery modules 120 belonging to the battery pack 100, and to determine the configuration of the battery pack 100. In an advantageous embodiment the RFID readers 114 may be arranged to capture signals from only one RFID module adjacent to the RFID reader 114 in question on the basis of which the above described method for determining the configuration may be established.

Moreover, in an implementation in which a RFID reader 114 of RFID module is capable of receiving signals from RFID tags 115 of RFID modules residing dis tantly i.e. not only from at least one adjacent RFID module, but one or more RFID modules residing further than the adjacent ones, the RFID readers 114 may be arranged to include further information to the data comprising at least the identifier of the battery module 120 provided by the RFID tag 115. The further data may e.g. comprise a value representing a signal strength of the received signal by the RFID reader 114. The experienced signal strength is dependent on the distant of the transmitter, i.e. the RFID tag 115, and by means of the value it is possible to create differentiation between the RFID tags 115. The differenti ation, in turn, enables the control unit 150 to“understand” the mutual distances between the RFID modules associated with respective battery modules 120 and by applying the information on the signal strengths with the identifiers the control unit 150 may establish the model. For example, it may be determined the closest battery module 120 on the basis of the signal strength and to apply the decision making with respect to the configuration as described. Naturally, the above de- scribed way of including the further data, such as signal strength value may also be applied in an implementation in which only the neighboring RFID modules, or specifically the RFID tags 115, are detected.

Alternatively or in addition to the signal strength value some other, or additional, data may also be included in the data to be transmitted to the control unit 150. In some example embodiments the RFID module may determine a direction from which at least the identifier data is received. The direction may be deter mined with respect to some reference value. By receiving the directional data together with the identifier data from the RFID module the control unit 150 may be arranged to differentiate the RFID tags 115 detected by a certain RFID mod- ule, and, hence, to determine the configuration of the battery pack 100 in more efficient way e.g. by determining the adjacent battery module 120 on the basis of the directional data.

Generally speaking, as regards to distances between communicating entities some hardware may be designed for maximizing read range, while other hard- ware is designed to limit read range. For example, the battery modules 120 may be configured so that read range is limited but the control unit 150 may be con figured to have read range maximized. For instance, antenna gain may be used for adjusting the read ranges. If an increased read range is needed, higher gain antennas may be used. On the other hand, if less read range is needed, lower gain antennas may be selected. Further, if the RFID tags 115 are read up close, very low gain proximity antennas may be used.

As is commonly known a higher gain antenna increases the power received from the RFID reader 114. If there is need to make sure that the antennas have a longer“reach,” then high gain antennas (e.g. 9 dBi, or higher) may be applied to. Due to application environment of the present invention battery cells 110 may require a tightly controlled configuration. For example, in systems where the RFID tag 115 will always be the same short distance away from the antenna, a high gain antenna simply isn’t needed. Even so-called proximity scan may be used so as to not read RFID tags 115 too far away and a low gain proximity RFID antenna is perfect for such a situation. Flence, the higher the gain, the higher the range of the antenna, and vice versa. Additionally, lower gain anten nas are smaller in size than high gain antennas; so, if in case application envi ronment has size restrictions in terms of the antenna’s dimensions, a lower gain RFID antenna may be experimented with. Another option to the optimization of antenna gain may be to use antenna po larization. If RFID tags 115 are aligned with the polarization of the antenna, lin ear polarized antennas may be read farther than circular polarized antennas. If RFID tags 115 are not aligned with the polarization of the antenna, then circular polarized antennas read farther than linear polarized antennas.

A still further option may be to control how much power is sent to the antennas. The higher the dB number, the more increase read range, and vice versa. Be cause the power is measured in decibels (dB), the power will double (or be cut in half) for every 3 dB you increase (or decrease). For example, 27 dB is twice as powerful as 24 dB, and 30 dB is twice as powerful as 27 dB. Lastly, RFID reader’s receive sensitivity settings may be set. If the RFID reader 114 is set to maximum sensitivity, it will report weaker RFID tag 115 signals (which typically come from tags that are farther away, thus increasing read range); a lower sen sitivity setting will ignore the weaker signals, thus decreasing read range. As may be seen from the above there are various mechanisms to affect read ranges of the RFID readers 114. By adjusting the setup it is e.g. possible to define the system so that each cell row is capable of“listening” to neighbor cells in the same row, and e.g. each of the first module 120of each row is capable of “listening” to neighboring first module 120 of the next column. The cell here cor- responds to a respective RFID tag 115.

According to various example embodiments of the invention the control unit 150 may be arranged to determine a number of battery modules 120 included in the battery pack 100 it is arranged to monitor in the manner as described. The awareness of the number of the battery modules 120 may e.g. be arranged so that information on the number of the battery modules 120 is stored in a memory 220 of the control unit 150, and the control unit 150 may be arranged to deter mine that it receives the signals comprising the data from the corresponding number of the RFID modules associated to the battery modules 120. Naturally, if one RFID module is arranged to represent a plurality of battery modules 120it is taken into account in the arrangement. The awareness of the number of the battery modules 120in the battery pack 100 also allows also the control unit 150 to set limits in the determination of the configuration, and in that manner a com plexity in the calculation may be reduced. In some example embodiment the control unit 150 may determine the number of the battery modules 120 by per- forming a calculation based on data received from the battery modules, for ex ample.

Alternatively or in addition, the complexity of the calculation may be optimized by giving consideration to applied RFID modules and/or their positions in the battery modules 120 of the battery pack 100. Namely, by arranging so that either RFID tags 115 under monitoring or the RFID reader 114 of the RFID module or both are arranged to communicate only in a certain direction, it is possible to define at least one rule for determining a configuration of the battery pack 100. In other words, if at least one RFID reader 114 may receive signals only from certain direction, or from a certain directional beam, the positions of the RFID modules with respect to each other may be defined in an efficient manner. Nat urally, the directions shall be defined so that the RFID readers 114 of the RFID modules receive signals from RFID tags 115 so that RFID readers 114 detect RFID tags 115 being common in order to be capable of establish the configura tion by means of common detections. As indicated, the directional detection may e.g. be achieved by selecting directional antennas either for RFID tags 115 or RFID readers 114 of the RFID modules and/or mounting them in the battery modules 120in a manner that the directional detection may be achieved.

In a simple example of the determination of the configuration of the battery pack 100, such as schematically illustrated in Figure 1 , it may be arranged that each battery module 120 has only one neighbour on a side into which a RFID reader 114 of the RFID module associated to the battery module 120 in question. Re spectively, a RFID tag 115 of a neighbouring battery module 120is arranged on the other side i.e. on the other battery module 120so as to enable a communi cation between the RFID reader 114 of a first module and the RFID tag 115 of the second module. Moreover, the positioning of the entities with respect to each other as well as technical parameters, such as described in the foregoing de scription, may be adjusted so that each RFID reader 114 may only read a signal from one neighbouring RFID tag 115. This means that the outermost RFID reader 114 does not receive any signal, i.e. sets the data identifying the at least one other battery module in the signal from a RFID reader 114 null, based on which it is possible to conclude that the corresponding battery module 120with which the RFID module 114 is associated with resides at one side (outmost) of the battery pack 100. Based on the mentioned detection the control unit 150 may start building up the configuration of the battery pack 100. In a similar man- ner, i.e. by limiting a capability to read a plurality of RFID tags 115 by the RFID readers 114, the configuration of the battery pack 100 may be determined in more complex structures of the battery packs 100. In other words, the build-up of the configuration of the battery pack 100 is based in relative positions of the RFID modules, i.e. the RFID readers 114 and RFID tags 115, associated to the battery module 120 of the battery pack 100.

For clarifying the determination of the configuration of the battery pack 100 it is referred to Figure 5. The battery pack 100 comprises a plurality of battery mod ules 120, referred as BM1 and BM2 in Figure 5. The battery modules 120 are equipped with RFID modules comprising a RFID reader 114 and a RFID tag 115. The arrangement is such that the RFID reader 114 is arranged to communi cate with a RFID tag 115 of an adjacent battery module 120 and to one direction only. The battery modules 120 comprise dedicated identifiers, referred as ID1 and ID2 in Figure 5. Now, each battery module 120 may be arranged to detect a neighbouring battery module 120 and receive its identifier ID1 , ID2, and to generate a data record comprising own identifier as a first data and an identifier of the neighbouring battery module 120 as a second data. A non-limiting exam ple of a format of the data record generated by the battery module 120 is sche matically illustrated in Figure 5 (ID-own; ID-neighbour). As a result, the battery modules 120, BM1 , BM2, may be arranged to transmit data records to the con- trol unit. The data record transmitted by the first battery module 120, BM1 , may comprise data as follows: ID1 ; IDO and the data record transmitted by the second battery module 120, BM2, may comprise data as follows: ID2; ID1. Correspond ingly other battery modules 120 may provide corresponding data records to the control unit 150. In response to the receipt of the data records the control unit may start establishing a model of the configuration of the battery pack 100. The above mentioned data records received from the first and from the second bat tery module 120, BM1 , BM2 comprise a common identifier i.e. an identifier of the first battery module 120, ID1. The detection allows the control unit 150 to determine that a mutual order of the battery modules 120 on the basis of re ceived data records is then BM0, BM1 , BM2 (battery module 120 BM0 not illus- trated in Figure 5). Correspondingly, an order of the battery modules 120 in the string may be determined with respect to additional battery modules 120.

In Figures 6A-6E it is schematically illustrated non-limiting examples of setups based on the principle as disclosed in Figure 5 for determining the configuration of the battery pack in accordance with the present invention. The embodiments disclosed in Figure 6A-6E are as follows:

Figure 6A: The control unit 150 may be arranged to receive data, such as to access the data stored in a memory of the control unit 150, which indicates a number of battery modules 120 in the battery pack 100 whose configuration is to be determined. The awareness of the number of the battery modules 120 may be applied in the determination so that the control unit 150 may be arranged to start determining the configuration of the battery pack 100 in response to a re ceipt of data from all the battery modules 120 as well as the control unit 150 may establish a framework of the battery pack 100 with the information on the num ber of the battery modules 120 for placing the battery modules 120 in the frame- work, and in that manner to enhance the determination of the configuration.

Figure 6B: The implementation of the invention according to Figure 6B is based on an idea that the control unit 150 does not know the number of battery modules 120 in the battery pack 100 in advance, but there is arranged a fixed tag, called as a frame tag 610 in the battery pack 100 suitable to be read by one RFID reader 114 of a battery module 120. Additionally, according to the embodiment a fixed RFID control reader 620 is arranged in the setup, such as in the frame structure or in the control unit 150, which is positioned in a known position for reading a tag residing in a certain position in the battery pack 100. Hence, the control unit 150 may accordingly receive two reference points to be used in the determination of the configuration of the battery pack 100. As the control unit may determine the identities of the reference points, i.e. the identity of the frame tag, IDF, and the identity of the control reader 620, IDC, from the data received by the control unit 150, it may position corresponding modules 120 in the battery pack 100 and use that information for positioning the other battery modules 120 in the battery pack 100. In such a manner the determination of the configuration of the battery pack 100 may be enhanced and the control unit 150 may be con figured to determine the number of battery modules 120 in the battery pack 100.

Figure 6C: Further implementation as schematically depicted in Figure 6C is based on an idea that the control unit 150 may receive, such as has access to, data indicating the number of battery modules 120 in the battery pack 100, and there is arranged a fixed RFID control reader 620 in the setup. The control reader 620 is positioned so that its position is known for reading a tag residing in a certain position in the battery pack 100. Hence, the control unit 150 may accordingly receive a reference point from the RFID control reader 620 and ap- ply the information on the number of battery modules 120 belonging to the bat tery pack 100 in question and use these pieces of information in the determina tion of the configuration of the battery pack in an efficient manner.

Figure 6D: Figure 6D illustrates an implementation which is based on an idea that the control unit 150 may receive, such as access to, data indicating the number of battery modules 120 in the battery pack 100, and there is arranged a frame tag 610 in the setup. The frame tag 610 is positioned so that its position is known by the control unit 150. Hence, the control unit 150 may accordingly receive a reference point from the frame tag 610 and apply the information on the number of battery modules 120 belonging to the battery pack 100 in question and use these pieces of information in the determination of the configuration of the battery pack in an efficient manner.

Figure 6E: A further sophisticated solution for determining the configuration of the battery pack 100 may be based on an idea that the battery modules 120, e.g. through RFID readers 114, may be arranged to communicate with each other. At least one of the battery modules 120 may be arranged to communicate with the control unit 150. In this kind of implementation, i.e. in a mesh-type com munication, the battery module 120 configured to communicate with the control unit 150 in addition to a communication of at least one other battery module 120 may be arranged to gather detection data, i.e. the identities, from other battery modules 120 and establishes a data record comprising the data received from other modules and derived internally. In response to the receipt of the data rec ord the control unit 150 may be arranged to generate a model of the configura tion of the battery pack 100 in the same manner as described. In other words, the second data transmitted by the battery module 120 communicating with the control unit 150 may comprise further data comprising identifiers of from detec tions by the other battery modules 120 i.e. a meshed chain of identities. This kind of arrangement has at least an advantage that the communication of the control unit 150 may be optimized, since it needs to communicate with one, or possibly with some, battery module 120. Moreover, the example embodiment of Figure 6E may also be based on an arrangement in which the control unit 150 receives the data indicating the number of battery modules 120 belonging to the battery pack, such as to the string of battery modules 120.

Embodiments may also be used for determining number and / or configuration of other types of modules than battery cells and battery modules. Not only may it be used for battery system up to container level, but the same type of auto matic configuration may be used for complete containers regardless of their con tent, for electronics in high numbers like diesel cylinder controllers, and in a sys tem the configurations on many levels may simultaneously be automatically de- tected. From packages inside a container to strings of containers and all the way to a complete container ship or container harbour, the hierarchical physical lo cation of every physical unit may be automatically detected.

For sake of completeness Figure 7 illustrates a RFID module according to an example embodiment as a simplified block diagram. The RFID module com- prises a processor 410 and a memory 420 storing data and computer program code 425. The RFID module may further comprise communication means 430, such as a communication interface, for wired or wireless communication with other apparatuses, such as with the control unit 150. and/or user I/O (input/out put) components. Additionally, the RFID module comprises at least RFID reader unit 114 comprising at least an antenna for communicating with one or more RFID tags 115 of other RFID modules. Depending on an implementation the RFID module may also comprise a RFID tag 115, but it may also be a separate entity to the RFID module. The mentioned entities in the RFID module may be communicatively coupled to each other via a bus 460 that enables transfer of data and control information between the components. The example of RFID module as illustrated in Figure 7 is a non-limiting example of the entity, and RFID modules having another implementation may be used to. In the non-limiting ex ample of Figure 5 both the RFID reader 114 and the RFID tag 115 of the same RFID module are schematically illustrated to reside in the same housing, but it may also be arranged that they are distinct entities arranged in the same battery cell 110 e.g. in a manner as schematically illustrated in Figure 1.

It should be noted that the examples described above and illustrated in at least some of the Figures are conceptual ones and omit a number of elements re quired in a real-life solution for determining a configuration of battery pack 100 and it may be varied or complemented in a number of ways without departing from the scope for determining a configuration of battery pack 100 as is de scribed in the present disclosure. As an example, in this regard, the battery mod ules 120 of the battery pack 100 may be a single RFID module, two or more RFID modules 115 arranged in a single physical location in the battery module 120 or in a plurality of locations both arrange to transmit the same identifier or different identifier. Further, the control unit 150 may be associated with the bat tery modules 120 or it may be remotely located e.g. within a distance a direct communication may be arranged with the control unit 150 and the RFID modules residing in the battery pack 100. Moreover, the control unit 150 should be con- strued as a logical entity, that may be provided as one or more separate entities or components, some of which may be co-located with the other elements as e.g. depicted in the example of Figure 1 and some of which may be remotely located. Flowever, the framework of Figure 1 is sufficient for description of vari ous characteristics of solution for determining the configuration of the battery pack 100 according to the present disclosure.

In the foregoing description of some embodiments it is derivable that for one battery pack 100 there is arranged only one control unit 150. Flowever, the pre sent invention is not only limited to such an implementation. For example, in a battery pack 100 there may be a plurality of control units 150 each arranged to determine a configuration of a predetermined number of battery modules 120 belonging to the battery pack 100. The control units 150 may be arranged to communicate with each other, and it may e.g. be arranged to only one of the control units 150 is arranged to determine the configuration of the whole battery pack 100 e.g. for maintenance purposes. One preferred outcome of the solution according to the present invention is an ability of such a system to perform a determination of a configuration of a battery pack, and, hence, a location battery cells therein. This allows swapping of faulty units without the need of a manual configuration of the system.

The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.