Monitoring of mechanical stress of a battery module

Abstract

An arrangement (200) for monitoring mechanical stress of a battery module (120) installed in a vehicle (100). The arrangement (200) comprises a sensor (140), configured to measure data indicative of a mechanical force acting on the battery module (120); and a controller (150), communicatively connected to the sensor (140). The controller (150) is configured to trigger output of an action when an obtained sensor measurement exceeds a threshold limit. A battery module (120), a battery pack (110), a method (400), a computer program and a vehicle (100) are also disclosed.

Description

[0001] MONITORING OF MECHANICAL STRESS OF A BATTERY MODULE

[0002] TECHNICAL FIELD

[0003] This document relates to an arrangement and a method for monitoring mechanical stress of a battery module installed in a vehicle, according to the appended independent claims. A computer program, computer-readable storage medium, a battery module, a battery pack and a vehicle are also disclosed.

[0004] BACKGROUND

[0005] An electric vehicle / hybrid electric vehicle comprises one or several battery packs. Each battery pack comprises several battery modules. Each battery module in turn comprises several battery cells.

[0006] A vehicle is subject to vibrations, acceleration / deceleration / lateral forces during cornering / propulsion, airflow during propulsion, impact when passing road bumps or various irregularities in the road surface, and possibly collision impact, etc. Components of the vehicle, for example battery modules thereof, are thereby exposed to vibrations and various mechanical forces, causing mechanical stress.

[0007] The involved parts related to the battery modules, the battery packs and involved cables are releasably connected to each other. Over time, vibrations and / or impacts may cause battery modules, their fasteners and / or attached cables to dislocate or even break. Displacement of the electric connections / cables / busbars may cause stress or cable break thereon.

[0008] A sudden impact for example may cause internal mechanical failure of battery module / s, immediately or after a period of time. Electric vehicles typically use high-voltage cables for providing electricity from the battery pack / s to the electric motor. It is important to maintain the battery modules and cables fixated for avoiding a potentially lethal accident.

[0009] In case of battery module malfunction, the vehicle is forced to make an emergency stop, thereby stalling transportation, a very undesired event. An emergency stop on a highway for example, may cause an accident in poor visibility conditions.

[0010] At the same time as it is required to assure that the battery modules and involved electric cables are fixated and are given a limited possibility to move, it is desired to facilitate an easy mounting of the battery modules and cables into the desired position, Regular service involving professional inspection of the battery modules may prevent failure of the batteries; this is however costly and require the vehicle to be provided to the workshop and being immobilised, thereby causing undesired and possibly unnecessary repeated stops in transport capacity.

[0011] It is desired to find a technical solution to these problems, predicting an increased risk of mechanical failure of the battery module and trigger appropriate measures before a failure occurs.

[0012] SUMMARY

[0013] It is an object of this invention to solve at least some of the above problems and enable improved prediction of mechanical failures of battery modules installed in a vehicle.

[0014] According to a first aspect of the invention, this objective is achieved by an arrangement for monitoring mechanical stress of a battery module, which is installed in a vehicle. The arrangement comprises a sensor, configured to measure data indicative of a mechanical force acting on the battery module.

[0015] The arrangement also comprises a controller, communicatively connected to the sensor and to the output device. The controller is configured to trigger an action when an obtained sensor measurement exceeds a threshold limit.

[0016] A battery failure of the vehicle is thereby predicted and prevented.

[0017] Optionally, the triggered action may comprise reducing vehicle velocity, either to below a maximum speed or to stand still.

[0018] Lower speed causes less vibrations and centrifugal forces during turning, for example, which promoted extended life-time of the battery module.

[0019] Optionally, the triggered action may comprise driving the vehicle to a service station for a service procedure of the battery module.

[0020] By assuring that functionality of the battery module and attached cables etc., are checked, triggered by excession of the corresponding threshold limit, mechanical failure of the battery module is prevented. The risk of severe accidents could be avoided while operability of the battery module is enhanced. Optionally, the arrangement may comprise an output device, configured to output an alert to either a driver, or an autonomous vehicle supervisor in case the vehicle is autonomous. The autonomous vehicle supervisor may be a human or a software. The controller is communicatively connected to the output device. The triggered action of the controller may comprise output the alert on the output device when the obtained sensor measurement exceeds a threshold limit.

[0021] Optionally, the output alert on the output device may comprise an instruction to reduce vehicle velocity.

[0022] The technical lifetime of the battery module is thereby extended.

[0023] Optionally, the output alert on the output device may comprise an instruction to perform a service procedure for the battery module comprising checking installation of the battery module, cable connections to / from the battery module and / or tightening involved fasteners.

[0024] Relative movements between the battery module and other battery modules or the frame due to vibrations, oscillation etc., may over time cause fasteners to come loose, cables to displace, cable connections to come off or even disconnect. A small displacement of the busbar and / or involved cables of the battery module may cause damage to the busbar / cable, for example due to friction or interference with some moving element, which easily could result in a dangerous accident as the cables / busbar of the battery module may comprise high-voltage. By assuring that these critical issues are checked, triggered by excession of the corresponding threshold limit, mechanical failure of the battery module is prevented. The risk of severe accidents could be avoided while operability of the battery module is enhanced.

[0025] Optionally, the output alert on the output device may comprise an instruction to replace the battery module.

[0026] By replacing the battery module before the mechanical stress of the battery module cause a technical failure of the battery module, it is avoided that the vehicle has to make an emergency stop during transportation.

[0027] Optionally, the sensor may be configured to measure a relative movement or distance variation, either between the battery module and another battery module, or between the battery module and a housing enclosing the battery modules. Hereby, data indicative of mechanical force acting on the battery module in form of relative movements, vibrations, oscillations, and / or friction between battery modules are detected. A measure indicating mechanical stress of the battery module is thereby achieved. By comparing this measurement data with a threshold limit, a mechanical failure of the battery module is predicted. By associating the threshold limit with an appropriate action, the mechanical failure could be prevented.

[0028] Optionally, the sensor may be arranged on an exterior lateral part of the battery module which is opposing either another battery module, or a housing enclosing the battery modules. The sensor may be configured to measure 3-axis friction and / or shear force acting on the battery module.

[0029] By measuring relative movements of the battery module in relation to other battery module / s and / or the housing, data indicative of mechanical force acting on the battery module is obtained.

[0030] Optionally, the arrangement may comprise a memory device, communicatively connected to the controller. The threshold limit may comprise an aggregated maximum limit / aggregated limit. The controller may be configured to aggregate sensor measurements over a time period in the memory device and compare the aggregated sensor measurements with the aggregated maximum limit / aggregated limit.

[0031] By aggregating data indicative of mechanical force acting on the battery module in form of relative movements, vibrations, oscillations, and / or friction between battery modules over a time period, a measurement of aggregated mechanical stress of the battery module is obtained, that could be utilised to predict mechanical failure. By the comparison with the aggregated maximum limit / aggregated limit, mechanical failure could be prevented or at least postponed.

[0032] Optionally, the sensor may be arranged on a rigid lateral part of the exterior of the battery module, such as a metal frame, which is opposing another rigid part, such as a metal frame of the adjacent battery module or a rigid part of the housing, enclosing the battery modules.

[0033] By measuring relative movements between rigid parts of the battery modules and / or the battery module and the housing, it is assured that movements relevant for estimating mechanical stress of the battery module is measured, and not for example minor flutter of a soft plastic shell around the battery module. Optionally, the sensor of the arrangement may be arranged approximately at a longitudinally central section of the battery module.

[0034] Due to the often-applied oblong shape of the battery modules, and that the battery modules often are fixated to the housing at the respective short sides of the battery module, the amplitude of a movement such as vibrations / oscillation affects the longitudinally central section of the battery module the most. By arranging the sensor to measure the data indicative of mechanical force of this section, it is assured that the mechanical stress of this critical section of the battery module is monitored.

[0035] Optionally, the controller of the arrangement may comprise a Cell Management Controller (CMC) of the battery module.

[0036] By modifying software and / or possibly also the hardware of the already existing CMC of the battery module, the inventive functionality is achieved without increasing the number of required computational components, which reduces complexity of the solution, and involved costs.

[0037] According to a second aspect of the invention, this objective is achieved by a method of a controller in an arrangement according to the first aspect. The method aims at monitoring mechanical stress of a battery module installed in a vehicle comprising the arrangement. The method comprises the step of triggering an action when an obtained sensor measurement exceeds a threshold limit.

[0038] The triggered action may cause reduced vibrations and / or mechanical stress of the battery module, for example by reducing speed. The triggered action may alternatively, or in addition comprise making a service check of the battery modules for checking installation of the battery module, cable connections to / from the battery module and / or tightening involved fasteners.

[0039] Hereby, operational life-time of the battery modules is extended. By triggering regular service checks, sudden emergency stops are avoided.

[0040] Optionally, the triggered action may comprise outputting an alert on an output device when the obtained sensor measurement exceeds the threshold limit.

[0041] By triggering an alert concerning an appropriate action to perform when the threshold limit is exceeded, a battery failure of the vehicle is thereby predicted and prevented. Optionally, the method according to the second aspect may also comprise the step of obtaining the sensor measurement from a sensor. The method may also comprise comparing the obtained sensor measurement with the threshold limit.

[0042] By measuring data indicative of mechanical force acting on the battery module and comparing this measurement with the threshold limit, status of the battery module is monitored, and performance of an appropriate measure is enabled.

[0043] According to a third aspect of the invention, this objective is achieved by a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method according to the second aspect.

[0044] By automizing the method according to the second aspect, it is assured that mechanical stress of the battery module is continuously monitored, for predicting mechanical failure of the battery module.

[0045] According to a fourth aspect of the invention, this objective is achieved by a computer-read- able storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method according to the second aspect.

[0046] According to a fifth aspect of the invention, this objective is achieved by a battery module. The battery module comprises a plurality of battery cells disposed within the battery module, wherein the battery cells are electrically interconnected. Also, the battery module comprises an electrical connector interface, positioned on the exterior of the battery module, for enabling electrical connection from / to the battery cells of the battery module. The battery module in addition comprises a busbar configured to interconnect the electrical connector interface of the battery module to another entity. Furthermore, the battery module also comprises an arrangement according to the first aspect, for monitoring mechanical stress of the battery module.

[0047] A reliable functionality of the battery module is achieved, thanks to the monitoring of the mechanical stress of the battery module made by the arrangement.

[0048] According to a sixth aspect of the invention, this objective is achieved by a battery pack. The battery pack comprises a plurality of battery modules according to the fifth aspect. Also, the battery pack comprises a housing, configured to enclose the plurality of battery modules. The battery pack also comprises an electrical connector interface, positioned on the exterior of the housing, for providing electrical communication between the plurality of battery modules and an external device.

[0049] According to a seventh aspect of the invention, this objective is achieved by an electric vehicle, comprising a battery pack according to the sixth aspect.

[0050] Thanks to the described aspects, a convenient solution is provided for monitoring mechanical stress of a battery module installed in a vehicle. Vibrations, acceleration / deceleration, air drag, possibly also unexpected impact of road bumps, sudden braking or collision may cause a mechanical force acting on the battery module, which are expected to reduce lifetime and / or functionality of the battery module, are measured. By triggering release of the alert concerning any relevant measure, mechanical failure of the battery module is avoided, or at least postponed.

[0051] Other advantages and additional novel features will become apparent from the subsequent detailed description.

[0052] FIGURES

[0053] Embodiments of the invention will now be described in further detail with reference to the accompanying figures, in which:

[0054] Figure 1 illustrates a vehicle comprising a battery pack, which in turn comprises a battery module, which comprises a plurality of battery cells; and an arrangement for monitoring mechanical stress of a battery module, according to embodiments of the invention;

[0055] Figure 2 illustrates an arrangement for monitoring mechanical stress of a battery module, according to embodiments of the invention;

[0056] Figure 3 illustrates a vehicle interior of a vehicle comprising an arrangement for monitoring mechanical stress of a battery module, according to embodiments of the invention;

[0057] Figure 4 illustrates a flow chart depicting method steps according to an embodiment of the invention.

[0058] DETAILED DESCRIPTION

[0059] Embodiments of the invention described herein are defined as an arrangement, a method, a computer program, a computer-readable storage medium, a battery module, a battery pack, and / or an electric vehicle, which may be put into practice in the embodiments described below. These embodiments may, however, be exemplified and realised in many different forms and are not to be limited to the examples set forth herein; rather, these illustrative examples of embodiments are provided so that this disclosure will be thorough and complete.

[0060] Still other objects and features may become apparent from the following detailed description, considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the herein disclosed embodiments, for which reference is to be made to the appended claims. Further, the drawings are not necessarily drawn to scale and, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

[0061] Figure 1 illustrates a scenario with a vehicle 100. The vehicle 100 may be an electric vehicle / hybrid electric vehicle using one or several electric motors for propulsion.

[0062] The vehicle 100 may comprise a means for transportation in broad sense such as e.g., a truck, a bus, a trailer, a car, a motorcycle, a bike, a train, a tram, an aircraft, a watercraft, a drone, a spacecraft, or other similar means of conveyance. The vehicle 100 may have a human driver or be autonomous in different embodiments.

[0063] Electric vehicles / hybrid electric vehicles 100 rely on one or several large-capacity battery packs 110, power inverters, and efficient distribution of power from a charging source to the battery pack 110 and throughout the vehicle 100.

[0064] The battery pack 110 comprises a plurality of battery modules 120 disposed within a housing 111 of the battery pack 110. In the example of Figure 1 , which is merely illustrative, the battery pack 110 comprises 5 battery modules 120. Other examples may comprise another number of battery modules 120, such as for example 5-50 battery modules 120, or more.

[0065] Each one of the battery modules 120 in turn comprises a plurality of battery cells 125 disposed within the battery module 120. In the illustrated example, which is merely illustrative, the battery module 120 comprises 13 battery cells 125. Other examples may comprise another number of battery cells 125, such as some hundred, or thousands of battery cells 125.

[0066] The battery modules 120 may often have an elongated shape, fixated to the housing 111 on the respective short sides, for example by screws or other appropriate fasteners.

[0067] The battery cells 125 are electrically interconnected within the battery module 120 to achieve desired voltage and capacity levels. The battery pack 110 also comprises an electrical connector interface, positioned on the exterior of the housing 111 , for providing electrical connection between the plurality of battery modules 120 and an external device, such as an electric machine, i.e., a motor and / or a generator; enabled to convert electricity to mechanical power, and / or vice versa.

[0068] Each battery module 120 comprises an electrical connector interface 135, positioned on the exterior of the battery module 120. The electrical connector interface 135 may comprise a positive connector on one short side and a negative connector on an opposite short side as illustrated in Figure 1 ; however other implementations are possible in other embodiments. Thereby, electrical connection from / to the battery cells 125 of the battery module 120 is enabled.

[0069] The interconnection of the battery modules 120 and / or connection between the battery modules 120 and the electrical connector interface is made by a busbar 130, or similar connection.

[0070] The busbar 130 is a conductive component, for example made of copper, aluminium, or other conductive material or alloy, designed to carry and distribute electric power. The busbar 130 may essentially comprise a thick strip or bar that provides a low-resistance path for electric currents. The busbar 130 may typically be coated or insulated to prevent accidental short circuits or contact with other components.

[0071] In the illustrated scenario of Figure 1 , only two busbars 130 are illustrated, for clarity reasons. In a more typical scenario, a large number of busbars 130 and cables may be comprised in the battery pack 110, and / or vehicle 100.

[0072] For monitoring stress and forces acting on the battery module 120, to thereby enable prediction of mechanical failures of each battery module 120 and the battery cells 125 and electrical connections comprised and / or involved therein, a sensor 140 may be applied. The sensor 140 is configured to measure data indicative of a mechanical force acting on one of the battery modules 120, such as relative movements and / or friction between battery modules 120, or between one battery module 120 and the housing 111.

[0073] In different embodiments, different application of the sensor 140 and / or different types of sensors 140 may be made, for example one sensor 140 may be applied on each battery module 120 in each battery pack 110 of the vehicle 100 thereby achieving a complete monitoring of the current status of the battery modules 120. In other embodiments, one sensor 140 may be applied on one representative battery module 120; or one respective sensor 140 on some battery modules 120.

[0074] Due to the frequently applied oblong shape of the battery modules 120, it may be assumed that vibrations / oscillation and other forces may affect a longitudinally central section of the battery module 120 most, as the amplitude of a sinusoid motion, simple harmonic motion or other periodic / cyclic motion will be largest in the longitudinally central section. For this reason, the longitudinally central section of the battery module 120 may be an appropriate location of the sensor 140.

[0075] The battery modules 120 are often made in plastic material, which is enforced by a metal frame, although other constructions may be applied. By applying the sensor 140 on a rigid part on an exterior of the battery module 120, such as a metal frame, which is situated in close vicinity of another rigid part, such as a metal frame of an adjacent battery module 120 or a rigid part of a supportive frame enclosing the battery modules 120 within a battery pack 110, it is avoided that flexibility of other, less rigid parts of the battery modules 120 absorb force impact and / or vibrations.

[0076] The sensor 140 may be a 3-axis friction sensor and / or a shear force sensor, configured to measure 3-axis friction and / or shear force, respectively, acting on the battery module 120.

[0077] Shear stress is a type of stress that is coplanar with the material cross-section and causes deformation (shear strain) in a material by slippage along a plane parallel to the imposed stress, e.g., between two lateral sections of two neighbour battery modules 120, opposite to each other. When shear force is applied, opposing forces act in a direction parallel to a surface and an angular change in the shape of the body appears.

[0078] The sensor 140 may be enabled to measure shear stress and shear strain in solid bodies when mechanical forces are applied, which mechanical forces are created from vibrations during transportation, or impact from holes, road bumps or other irregularities in the road; or when load is put on a cargo area of the vehicle 100 for example.

[0079] The sensor 140 may be based on several technologies and materials, such as for example piezoelectric materials, piezoresistive materials, Fiber Bragg Grating, capacitive sensing, and structural colours.

[0080] The sensor 140 may for example comprise an optical sensor such as a camera, a video camera, a radar, a lidar, an ultrasound device, a time-of-f light camera, or similar device, in different embodiments. The data indicative of the mechanical force acting on the battery module 120 may comprise amplitude of movements of the battery module 120, and / or aggregated movement distance of the battery module 120, as measured by the sensor 140, operating in conjunction with a computer program for image recognition, or data analysis.

[0081] The sensor 140 may be based on the concept of emitting a continuous wave of microwave radiation and detect motion through the principle of Doppler, for example a Laser Doppler Vibrometer (LDV) or by a Doppler radar; or by emitting an ultrasonic wave and detecting and analysing the reflections; or by a tomographic motion detection system based on detection of radio wave disturbances, to mention some possible implementations.

[0082] Thanks to the applied sensor 140, a health monitoring of the battery modules 120 is achieved. Stress / strain of involved materials is monitored and fracture in the materials of the battery modules 120 and / or the comprised battery cells 125 may be predicted in a relevant way.

[0083] Figure 2 illustrates an arrangement 200 for monitoring mechanical stress of a battery module 120 installed in a vehicle 100, for example an electric truck or bus. The battery module 120 is illustrated by a dashed line.

[0084] The arrangement 200 comprises a sensor 140, configured to measure a mechanical force acting on the battery module 120.

[0085] The arrangement 200 also comprises a controller 150, for example a Cell Management Controller (CMC) of the battery module 120. The controller 150 / CMC is a comprehensive cell supervision circuit that monitors and controls individual cells in high voltage batteries, providing real-time data on battery performance and health. The controller 150 / CMC may for example be operative to monitor critical battery cell characteristics such as for example voltages, temperatures, current, etc.

[0086] The controller 150 is communicatively connected to the sensor 140 and is configured to obtain a sensor measurement from the sensor 140. The controller 150 is also configured to compare the obtained sensor measurement with a threshold limit. The threshold limit may comprise an aggregated maximum limit / aggregated limit in different embodiments. The controller 150 is additionally configured to trigger an action when the obtained sensor measurement exceeds the threshold limit. The triggered action may comprise an appropriate action for reducing vibrations and / or mechanical stress of the battery module 120 such as reducing speed. Also, or alternatively, the triggered action may comprise driving the vehicle 100 to a service station for a service procedure of the battery module 120.

[0087] However, the proposed action may comprise outputting an alert on an output device 170, communicatively connected to the controller 150. The output alert may concern a recommended action, such as for example decrease speed, make a service procedure for the battery module 120 comprising checking installation of the battery module 120, cable connections to / from the battery module 120 and / or tightening involved fasteners.

[0088] The output device 170 is configured to output an alert to either a driver, or an autonomous vehicle supervisor (which may be a human operator, or alternatively a software). In some embodiments wherein the vehicle 100 is autonomous yet comprising passengers (for example an autonomous bus), information may be output to the passenger / s, informing concerning the triggered action that the vehicle 100 is to make, for example reducing speed or disrupt the driving route and drive to a workshop, etc. Passengers may be advised to change to another upcoming vehicle for continuing the route, for example.

[0089] The arrangement 200 may also comprise a memory device 160, communicatively connected to the controller 150. The memory device 160 may store threshold limit values for different parameters, such as an aggregated maximum limit, and / or an aggregated limit.

[0090] Data indicative of mechanical force acting on the battery module 120 over a time period may thereby be aggregated and stored in the memory device 160, continuously or according to a predetermined schedule. The controller 150 may then obtain the aggregated and stored data from the memory device 160 and make a comparison with the aggregated maximum limit / aggregated limit, also obtained from the memory device 160, in some embodiments.

[0091] In some embodiments, a plurality of threshold limit values may be stored in the memory device 160, each associated with triggering of a corresponding measure. Thus, when the sensor measurement exceeds a first (low) threshold limit, an action comprising an alert and / or a command may be generated to decrease speed; when the sensor measurement exceeds a second (higher) threshold limit, an action comprising an alert and / or command may be generated to perform a service procedure for the battery module 120 comprising checking installation of the battery module 120, cable connections to / from the battery module 120 and / or tightening involved fasteners, etc. Another example of action and / or alert that may be triggered by the controller 150 may be to exchange one or several battery modules 120. For example, one or several battery modules 120 of a vehicle 100 being exposed to very high mechanical stress, may be exchanged for new battery modules 120; or possibly exchanged with battery modules 120 of another vehicle with very low exposure of mechanical stress, or a battery module 120 of a stationary structure, for example an off-grid energy storage system. Also, or alternatively, cables, and / or busbars may be controlled, and / or exchanged.

[0092] By measuring mechanical stress of one or several battery modules 120 on a vehicle 100, a general estimation of mechanical stress in form of aggregated vibrations and / or amplitude of sudden impact forces of the vehicle 100 is / are achieved, which may trigger also other service measures. Instead of triggering service measures based on either a time schedule (e.g. once a year) and / or according to number of driven kilometres, it may be more appropriate to trigger certain service measures based on exposure to mechanical stress, i.e. vibrations and / or impact; for example to check that cables are held / maintained in correct position, that screws are tightened with the correct respective torque, that elements in particular sensible for vibrations e.g. sensors and or lamps are controlled / exchanged before they (could be expected to) suffer a mechanical failure, etc.

[0093] Figure 3 illustrates a scenario of a vehicle cabin as seen by a driver, if any. Two examples of output devices 170 are schematically illustrated, by which the controller 150 may trigger an action / output of an alert for action when an obtained sensor measurement exceeds a corresponding threshold limit. Some examples of output devices 170 may be visual output devices such as a display, a projector, a screen on a user device, a Head-up Display; an auditive output device such as a loudspeaker; a tactile / haptic output device, etc.

[0094] Figure 4 illustrates an example of a method 400 according to an embodiment. The flow chart in Figure 4 shows the method 400 of a controller 150 in an arrangement 200 for monitoring mechanical stress of a battery module 120 installed in a vehicle 100 comprising the arrangement 200.

[0095] The vehicle 100 may be any arbitrary kind of means for conveyance as previously enumerated and exemplified, such as a truck, a trailer, a bus. The vehicle 100 may be part of an intelligent transportation system in some embodiments, i.e. autonomous vehicles and / or vehicles driving in a platoon.

[0096] In order to be able to monitor mechanical stress of the battery module, the method 400 may comprise a number of steps 401-403. However, some of these steps 401-403 may be performed solely in some alternative embodiments, like e.g. steps 401 and / or 402. Further, the described steps 401-403 may be performed in a somewhat different chronological order than the numbering suggests. The method 400 may comprise the subsequent steps:

[0097] Step 401 , which may be performed only in some alternative embodiments, comprises obtaining a sensor measurement from a sensor 140. The sensor measurement comprises data indicative of a mechanical force acting on the battery module 120.

[0098] The measured data may comprise relative movement or distance variation, either between the battery module 120 and another battery module 120, or between the battery module 120 and a housing 111 enclosing the battery modules 120. The measured data may for example comprise friction and / or shear force acting on the battery module 120.

[0099] In some embodiments, the data may be collected and stored in a memory device 160, communicatively connected to the controller 150. Thereby, the data indicative of mechanical force acting on the battery module 120 may comprise aggregated sensor measurements over a time period, retrieved from the memory device 160.

[0100] Step 402, which may be performed only in some alternative embodiments wherein step 401 has been performed, comprises comparing the obtained 401 sensor measurement with a threshold limit.

[0101] The threshold limit may comprise a maximum impact limit, setting a limit for a single impact force acting on the battery module 120. The threshold limit may also, or alternatively comprise an aggregated maximum limit / aggregated limit, concerning aggregated sensor measurements collected over a time period, for example collected since production of the vehicle 100, and / or the latest year, the latest x weeks, etc.

[0102] In some embodiments wherein the sensor 140 is measuring oscillation movements over time, the threshold limit may comprise oscillation distance over time, which oscillation movements is considered indicative of the mechanical force acting on the battery module 120.

[0103] In some embodiments, the comparison may be made against several threshold limits.

[0104] Step 403 comprises triggering an action when an obtained sensor measurement exceeds a threshold limit. The triggered 403 action may comprise reducing vehicle velocity in some embodiments, thereby reducing vibrations and mechanical stress of the battery modules 120. Also, or alternatively, the triggered 403 action may comprise driving the vehicle 100 to a service station for a service procedure of the battery module 120.

[0105] The triggered 403 action may comprise output of an alert on an output device 170 when the obtained 401 sensor measurement exceeds the threshold limit.

[0106] In some embodiments, wherein comparison has been made against several threshold limits, different actions may be triggered when an associated threshold limit is exceeded.

[0107] The previously described method steps 401-403 to be performed in the controller 150 may be implemented togetherwith a computer program product and a computer-readable storage medium for performing at least some of the functions of the method steps 401-403. Thus, a computer program product, comprising instructions for performing the method steps 401-403 in the controller 150 may perform the method 400 comprising at least some of the method steps 401-403 for monitoring mechanical stress of a battery module 120 installed in a vehicle 100 comprising the arrangement 200, when the computer program is loaded into the controller 150.

[0108] A computer could be comprised in the control arrangement / controller 150. “Computer” is defined as any hardware or hardware / firmware device implemented using processing circuity such as, but not limited to, a processor, Central Processing Unit (CPU), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, an application-specific integrated circuit, or any other device capable of electronically performing operations in a defined manner.

[0109] In some embodiments, a computer-readable medium may be a non-transitory computer- readable medium, such as a tangible electronic, magnetic, optical, infrared, electromagnetic, and / or semiconductor system, apparatus, and / or device.

[0110] The computer program product may be a computer readable medium and the computer program may be stored in a computer readable medium.

[0111] The terminology used in the description of the embodiments as illustrated in the accompanying drawings is not intended to be limiting of the described arrangement 200; method 400; computer program; computer-readable storage medium; battery module 120; battery pack 110; and / or electric vehicle 100. Various changes, substitutions and / or alterations may be made, without departing from invention embodiments as defined by the appended claims. Elements of different embodiments may be combined with each other, thereby achieving additional advantages.

[0112] As used herein, the term “and / or” comprises any and all combinations of one or more of the associated listed items. The term “or” as used herein, is to be interpreted as a mathematical OR, i.e. , as an inclusive disjunction; not as a mathematical exclusive OR (XOR), unless expressly stated otherwise. In addition, the singular forms “a”, “an” and “the” are to be inter- preted as “at least one”, thus also possibly comprising a plurality of entities of the same kind, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and / or “comprising”, specifies the presence of stated features, actions, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, ele- ments, components, and / or groups thereof. A single unit such as e.g., a structural element may fulfil the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

PATENT CLAIMS1. An arrangement (200) for monitoring mechanical stress of a battery module (120) installed in a vehicle (100), wherein the arrangement (200) comprises: a sensor (140), configured to measure data indicative of a mechanical force acting on the battery module (120); a controller (150), communicatively connected to the sensor (140); wherein the controller (150) is configured to trigger an action when an obtained sensor measurement exceeds a threshold limit.

2. The arrangement (200) according to claim 1 , wherein the triggered action comprises reducing vehicle velocity.

3. The arrangement (200) according to any one of the preceding claims, wherein the triggered action comprises driving the vehicle (100) to a service station for a service procedure of the battery module (120).

4. The arrangement (200) according to any one of the preceding claims, comprising an output device (170), configured to output an alert to either a driver, or an autonomous vehicle supervisor; wherein the controller (150) is communicatively connected to the output device (170); and wherein the triggered action of the controller (150) comprises output the alert on the output device (170) when the obtained sensor measurement exceeds a threshold limit.

5. The arrangement (200) according to claim 4, wherein the output alert on the output device (170) comprises an instruction to reduce vehicle velocity.

6. The arrangement (200) according to any one of claims 4-5, wherein the output alert on the output device (170) comprises an instruction to perform a service procedure for the battery module (120) comprising checking installation of the battery module (120), cable connections to / from the battery module (120) and / or tightening involved fasteners.

7. The arrangement (200) according to any one of claims 4-6, wherein the output alert on the output device (170) comprises an instruction to replace the battery module (120).

8. The arrangement (200) according to any one of the preceding claims, wherein the sensor (140) is configured to measure a relative movement or distance variation, either between the battery module (120) and another battery module (120), or between the battery module (120) and a housing (111) enclosing the battery modules (120).

9. The arrangement (200) according to any one of the preceding claims, wherein the sensor (140) is arranged on an exterior lateral part of the battery module (120), which is opposing either another battery module (120), or a housing (111) enclosing the battery modules (120); and wherein the sensor (140) is configured to measure 3-axis friction and / or shear force acting on the battery module (120).

10. The arrangement (200) according to any one of the preceding claims, further comprising a memory device (160), communicatively connected to the controller (150); wherein the threshold limit comprises an aggregated maximum limit / aggregated limit; and wherein the controller (150) is configured to aggregate sensor measurements over a time period in the memory device (160) and compare the aggregated sensor measurements with the aggregated maximum limit / aggregated limit.

11. The arrangement (200) according to any one of the preceding claims, wherein the sensor (140) is arranged on a rigid lateral part of the exterior of the battery module (120), such as a metal frame, which is opposing another rigid part, such as a metal frame of the adjacent battery module (120) or a rigid part of the housing (111), enclosing the battery modules (120).

12. The arrangement (200) according to any one of the preceding claims, wherein the sensor (140) is arranged approximately at a longitudinally central section of the battery module (120).

13. The arrangement (200) according to any one of the preceding claims, wherein the controller (150) comprises a Cell Management Controller of the battery module (120).

14. A method (400) of a controller (150) in an arrangement (200) according to any one of the preceding claims, for monitoring mechanical stress of a battery module (120) installed in a vehicle (100) comprising the arrangement (200), wherein the method (400) comprises the step of: triggering (403) an action when an obtained sensor measurement exceeds a threshold limit.

15. The method (400) according to claim 14, wherein the triggered (403) action comprises output of an alert on an output device (170).

16. The method (400) according to any one of claims 14-15, comprising the additional steps of: obtaining (401) the sensor measurement from a sensor (140); and comparing (402) the obtained (401) sensor measurement with the threshold limit.

17. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method (400) according to any one of the claims 14-16.

18. A computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method (400) according to any one of the claims 14-16.

19. A battery module (120), comprising a plurality of battery cells (125) disposed within the battery module (120), wherein the battery cells (125) are electrically interconnected; an electrical connector interface (135), positioned on the exterior of the battery module (120), for enabling electrical connection from / to the battery cells (125) of the battery module (120); a busbar (130) configured to interconnect the electrical connector interface (135) of the battery module (120) to another entity; and an arrangement (200), according to any one of the claims 1-14, configured for monitoring mechanical stress of the battery module (120).

20. A battery pack (110), comprising a plurality of battery modules (120) according to claim 19; a housing (111), configured to enclose the plurality of battery modules (120); an electrical connector interface, positioned on the exterior of the housing (111), for providing electrical communication between the plurality of battery modules (120) and an external device.

21. An electric vehicle (100), comprising a battery pack (110) according to claim 20.

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