Ev battery hot spot detection system and method therefor

Abstract

An Electric Vehicle (EV) battery hot spot detection system for use with at least two neighboring parked EVs for issuing a hot spot alarm for a parked EV determined to be susceptible of an impending thermal runaway on the condition that, within a predetermined time period from its determination, no other parked EV is additionally determined susceptible to an impending thermal runaway. The EV battery hot spot detection system includes a multitude of IR detector end units each deployed adjacent a single associated parked EV for remote acquiring its EV battery temperature measurements. Each IR detector end unit includes at least two adjacent single pixel IR sensors for independently acquiring a sequential series of single instantaneous EV battery temperature measurements.

Description

[0001] EV BATTERY HOT SPOT DETECTION SYSTEM

[0002] AND METHOD THEREFOR

[0003] FIELD OF THE INVENTION

[0004] The invention relates to remote surveillance of parked Electric Vehicles (EVs) for providing early warnings regarding impending thermal runaways.

[0005] BACKGROUND OF THE INVENTION

[0006] Parked Electric Vehicles (EVs) are known to suffer from rare occurrences of so-called thermal runaway in which a single malfunctioning EV battery cell becomes uncontrollably increasingly hotter to a critical temperature leading to smoke emission and possibly an explosion causing personal injury and considerable damage to surrounding property' including neighboring EVs in carparks with closely packed neighboring EVs. Impending thermal runaways are inherently difficult to predict because a malfunctioning EV battery cell can become increasingly hotter to its critical temperature over a time period ranging from several minutes to several hours. Moreover, a malfunctioning EV battery cell can be randomly located in an EV battery towards its front or rear end, towards its left or right side, or centrally located. Thermal runaway can occur both in the case of a parked EV being charged or not being charged.

[0007] Surveillance approaches for monitoring parked EVs for early detection of an impending thermal runaway such that preventive action can be taken are known in the prior art. Such preventive action can include inter alia isolating a parked EV to a safe location, placing a protective covering over a parked EV, and the like. One surveillance approach includes deploying a high resolution infrared (IR) camera with a typical 30 Hz frame rate for remotely acquiring a thermal footprint of an outwardly facing EV batery surface for acquiring temperature measurements of individual EV batery cells for determining if a single EV battery cell is malfunctioning and becoming uncontrollably increasingly hoter to a critical temperature compared to its neighboring EV battery cells. Or alternatively, an IR camera is deployed for remotely acquiring a thermal footprint of an outwardly facing EV battery surface for acquiring temperature measurements of groups of EV battery7cells for comparing to neighboring groups of EV batery7cells for determining if a group of EV batery7cells includes a malfunctioning EV battery cell becoming uncontrollably' increasingly hotter to a critical temperature. Such deployments typically require considerable computing power to process the temperature measurements, and are costly solutions.

[0008] EV battery hot spot detection systems are disclosed in inter alia CN 111114360, CN 112026547, CN 112370703, CN 114056148, CN 114592736, CN 116482548, CN 117298483, CN 212817723, DE 102005058315, JP 7332804, KR 20230026605, KR 20230138582, TW 202402351, US 11,309,596, US 11,538,320, US 11,538,321, US 2008 / 272742, US 2014 / 0152445, US 2022 / 0044023, US 2024 / 0001186, and WO 2023 / 242585.

[0009] SUMMARY OF THE INVENTION

[0010] In accordance with the present invention, an Electric Vehicle (EV) batery hot spot detection system for use with at least two neighboring parked EVs, each parked EV having an EV batery with an outwardly facing, generally horizontal batery surface, the EV batery hot spot detection system including a multitude of IR detector end units external to the at least two neighboring parked EVs for remote acquiring EV batery temperature measurements of their outwardly facing, generally horizontal batery surfaces. Each IR detector end unit is deployed adjacent a single associated parked EV’s EV batery of the at least two neighboring parked EVs for remote acquiring its EV batery temperature measurements. Each IR detector end unit includes at least two adjacent single pixel IR sensors for independently acquiring a sequential series of single instantaneous EV batery temperature measurements of at least some of its single associated parked EV’s outwardly facing, generally horizontal batery surface, each sequential series of single instantaneous EV batery temperature measurements being independently tested in accordance with at least one moving window test for rendering a positive moving window test result on counting a predetermined at least minimum number of a predetermined at least minimum temperature increment during a predetermined number of last consecutive EV battery temperature measurements, thereby enabling determination a parked EV of the at least two neighboring parked EVs is susceptible to an impending thermal runaway. The EV battery hot spot detection system also includes a controller for issuing a hot spot alarm for a susceptible parked EV of the at least two neighboring parked EVs on the condition that, within a predetermined time period from its determination, no other parked EV of the at least two neighboring parked EVs is additionally determined susceptible to an impending thermal runaway.

[0011] The present invention is based on the following understandings:

[0012] First, an impending thermal runaway can be inferred by detecting the contribution of a single malfunctioning EV battery cell to a temperature increment in an outwardly facing EV battery surface’s overall temperature without detecting the individual malfunctioning EV battery cell itself. This understanding enables implementation of IR detector end units with single pixel infrared (IR) sensors for remote surveillance external to a parked EV in comparison to high resolution IR camera deployments. Moreover, single pixel IR sensors can be configured for acquiring EV battery temperature measurements at a considerably lower rate than IR cameras. It is envisaged that IR detector end units with single pixel IR sensors of the present invention will preferably acquire EV battery temperature measurements, say, every 20 seconds or thereabouts, thereby requiring considerably less computing power for processing same and also reducing power consumption which is particularly advantageous for battery powered IR detector end units.

[0013] Second, the unpredictability of thermal runaway development is solved by concurrently executing at least two moving window tests on the EV battery temperature measurements of an IR detector end unit’s at least two adjacent single pixel IR sensors. Each moving window test can independently render a positive moving window test result on counting a predetermined at least minimum number of predetermined at least minimum temperature increments during a predetermined number of last consecutive EV battery temperature measurements. Three preferred moving window tests include a Short Moving Window Test (SMWT) for counting large temperature increments for detecting a rapid developing thermal runaway, an Intermediate Moving Window Test (IMWT) for counting intermediate temperature increments for detecting an intermediate developing thermal runaway, and a Long Moving Window Test (LMWT) for counting small temperature increments for detecting a slow developing thermal runaway.

[0014] And third, the premise of an extremely low likelihood that neighboring parked EVs would be simultaneously susceptible to thermal runaway and therefore they can be employed as a robust baseline for taking into account a wide variance of parking conditions including inter alia time of day, weather conditions, carpark locations, and the like, for enabling highly reliable prediction of thermal runaways with minimum false alarms. For the purpose of the present invention, the notion of neighboring parked EVs is intended to convey parked EVs in the same vicinity and subject to similar parking conditions and not necessarily physical distance. For example, in the case of a multi-floor carpark, neighboring parked EVs could be at opposite ends of the same floor. Against that, parked EVs on an overground floor and an underground floor of the same multi-floor carpark would probably not be considered neighboring parked EVs notwithstanding that their vertical distance may be shorter than the horizontal distance of two parked EVs at opposite ends on the same carpark floor. Accordingly, installation of an EV battery hot spot detection system of the present invention includes empirically determining which locations of parked EVs are considered neighboring parked EVs.

[0015] The use of neighboring parked EVs as a baseline for verifying an impending thermal runaway necessarily considers their independent random arriving at a carpark and leaving the carpark such that acquisition of their EV battery temperature measurements is correspondingly asynchronous. Also some parked EVs may be being charged and other parked EVs may not be being charged. Charging an EV battery inherently causes it to become hotter compared to it not being charged. Moreover, the charging rate of an EV battery affects its temperature profile in terms of maximum temperature and rate of becoming hotter. Accordingly, determination that a parked EV is susceptible to an impending thermal runaway in accordance with the present invention preferably takes into consideration whether its EV battery is being charged or not.

[0016] After determination a parked EV is susceptible to an impending thermal runaway, a predetermined time period is started. The predetermined time period is necessarily at least the time interval between consecutive EV battery temperature measurements. In the case of consecutive EV battery temperature measurements every 20 seconds, a predetermined time period is typically between 25 seconds to 40 seconds. The predetermined time period is typically the same for the three tests SMWT, IMWT and LMWT. In the case of determination of another parked EV being additionally susceptible to an impending thermal runaway within the predetermined time period, then the parked EV’s determination is considered to be a false alarm. Conversely, if no other parked EV is additionally determined susceptible to an impending thermal runaway in the predetermined time period, then the parked EV’s determination is considered to be a true indication of an impending thermal runaway, and accordingly a hot spot alarm is issued with respect to the parked EV such that preventive action can be taken.

[0017] EV battery hot spot detection systems of the present invention designed for remote acquiring of EV battery temperature measurements of outwardly facing EV battery surfaces are required to take into account different factors: First, an EV battery size and location. Family EVs, electric trucks, and the like, typically have a chassis mounted EV battery while electric buses typically have a roof-mounted EV battery. Electric trucks and electric buses typically have EV batteries which are considerably longer, wider and taller than a family EV’s EV battery. Second, the technical specification of an IR detector end unit in terms of its surveillance area, its thermal energy sensitivity to IR radiation fluence J / cm2, and the like. And third, an intended placement of an IR detector end unit relative to a parked EV taking into account accessibility considerations, namely, how close an IR detector end unit can be placed to an EV battery, and the like. Depending on an EV battery size, and an IR detector end unit’s technical specification and its intended placement, two or more IR detector end units may be required to completely monitor an outwardly facing EV battery surface to avoid unmonitored blind spots.

[0018] IR detector end units of the present invention can be intended for permanent deployment or temporary deployment. In the case of permanently deployed IR detector end units, they can be intended to be installed in preprepared trenches such that they are flush with a parking space or surface mounted for remote monitoring underside EV battery surfaces. Or alternatively, IR detector end units can be installed on posts, ceilings, and the like, for remote monitoring topside EV battery surfaces. In case of temporarily deployed IR detector end units, they are necessarily sufficiently robust not to be damaged by an EV driving thereover similar to a surface mounted permanently deployed IR detector end units.

[0019] EV battery hot spot detection systems of the present invention can be supplemented with close circuit TV for acquiring visual images which can be processed for smoke detection, and / or smoke detectors, and / or fire extinguishing systems for extinguishing an EV battery fire.

[0020] EV battery hot spot detection systems of the present invention are suitable for remote monitoring Hybrid Electric Vehicles (HEVs), Plug-In Electric Vehicles (PHEVs), and Battery Electric Vehicles (BEVs).

[0021] BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to understand the present invention and to see how it can be carried out in practice, preferred embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings in which similar parts are likewise numbered.

[0023] Fig. 1 is a schematic representation of an EV battery hot spot detection system for remote monitoring of parked EVs for issuing hot spot alarms. Fig. 2 is a schematic representation of a family EV.

[0024] Fig. 3 is a schematic representation of an EV battery and an EV cell.

[0025] Fig. 4 is a schematic perspective view of a fixed wired IR detector end unit of the EV battery hot spot detection system.

[0026] Fig. 5 is a schematic perspective view of a portable wireless IR detector end unit of the EV battery hot spot detection system.

[0027] Fig. 6 is a top plan of an IR detector end unit deployed in front of an EV front end.

[0028] Fig. 7 is a side elevation of the Figure 6 deployment.

[0029] Fig. 8 is a schematic bottom plan of an IR detector end unit remote monitoring a parked EV having an EV battery hot spot located in a single pixel IR sensor field of view.

[0030] Fig. 9 is a schematic bottom plan of an IR detector end unit remote monitoring a parked EV having an EV battery hot spot located in an overlapping area of two adjacent single pixel IR sensor fields of view.

[0031] Fig. 10 is a top plan of an IR detector end unit deployed alongside a parked EV.

[0032] Fig. 11 is a front elevation of the Figure 10 deployment.

[0033] Fig. 12 is a top plan of an IR detector end unit centrally deployed under a parked EV.

[0034] Fig. 13 is a side elevation of the Figure 12 deployment.

[0035] Fig. 14 is a schematic temperature versus time graph for a Rapid Developing Thermal Runaway (RDTR), an Intermediate Developing Thermal Runaway (IDTR) and a Slow Developing Thermal Runaway (SDTR).

[0036] Fig. 15 is a table listing parameters of a Short Moving Window Test (SMWT), an Intermediate Moving Window Test (IMWT) and a Long Moving Window Test (LMWT).

[0037] Fig. 16 is a table of temperature measurement number, temperature measurement To, delta To, a Short Moving Window Test (SMWT) counter, an Intermediate Moving Window Test (IMWT) counter and a Long Moving Window Test (LMWT) counter resulting in a positive SMWT result. Fig. 17 is a table of temperature measurement number, temperature measurement To, delta To, a Short Moving Window Test (SMWT) counter, an Intermediate Moving Window Test (IMWT) counter and a Long Moving Window Test (LMWT) counter resulting in a positive IMWT result.

[0038] Fig. 18 is a table of temperature measurement number, temperature measurement To, delta To, a Short Moving Window Test (SMWT) counter, an Intermediate Moving Window Test (IMWT) counter and a Long Moving Window Test (LMWT) counter resulting in a positive LMWT result.

[0039] Fig. 19 is a table of temperature measurement number, temperature measurement To, delta To, a Short Moving Window Test (SMWT) counter, an Intermediate Moving Window Test (IMWT) counter and a Long Moving Window Test (LMWT) counter resulting in a positive SMWT result, a positive IMWT result and a positive LMWT result.

[0040] Fig. 20 is a top level flow diagram of EV battery hot spot alarm logic for issuing EV battery hot spot alarms.

[0041] Fig. 21 is a schematic representation of a wireless EV battery hot spot detection system.

[0042] Fig. 22 is a schematic representation of a deployment of the Figure 21 wireless EV battery hot spot detection system on a car carrier vessel.

[0043] DETAILED DESCRIPTION OE DRAWINGS

[0044] The present description is divided into the following four sections: Section 1: EV battery hot spot detection system

[0045] Section 2: IR detector end units and their deployments

[0046] Section 3: Operation of EV battery hot spot detection system

[0047] Section 4: Wireless EV battery hot spot detection systems

[0048] Section 1: EV battery hot spot detection system

[0049] Figure 1 shows an EV battery hot spot detection system 100 for remote monitoring a carpark configured for a multitude of neighboring parked EVs. The carpark can be an indoor carpark, for example, an underground carpark, a multi-floor carpark, a sea going car carrier, and the like, or an outdoor carpark. The EV battery hot spot detection system 100 includes a controller 110 for implementing EV battery hot spot alarm logic 111 for selectively issuing an EV battery hot spot alarm regarding a parked EV which is regarded as being susceptible to an impending thermal runaway. The EV battery hot spot detection system 100 includes a multitude of IR detector end units 120 for remote monitoring the parked EVs for acquiring sequential series of EV battery temperature measurements. Each IR detector end unit 120 is intended to monitor a single associated parked EV only. The EV battery hot spot detection system 100 requires at least two neighboring parked EVs for comparison purposes and preferably more than two neighboring parked EVs. The parked EVs may be being charged or not being charged. The EV battery hot spot detection system 100 can include machine learning functionality and / or Al functionality for assisting in determining which parked EVs are susceptible to an impending thermal runaway.

[0050] IR detector end units 120 can have a wide range of specifications depending on an EV battery hot spot detection system 100’s intended deployment. For illustrative purposes of the present description only, two types of IR detector end units 120 are described as follows: Fixed wired IR detector end units 120 A and portable wireless IR detector end units 120B.

[0051] Fixed wired IR detector end units 120 A have the following typical specification: Mains powered or battery powered. Intended for permanent deployment in a pre-prepared trench or surface mounting in which case they are sufficiently robust not to be damaged by an EV driving thereover. Onboard processing module with low functionality. Bi-directional telecommunication with the controller 110. End unit alarms, for example, flashing light, buzzer, and the like, for providing an end unit alarm such that an operator can readily identify a parked EV determined susceptible to an impending thermal runaway.

[0052] Portable wireless IR detector end units 120B intended for temporary deployment have the following typical specification: Battery powered. Small and portable. -Uni-directional upload wireless communication with the controller 110 and onboard processing module with high functionality for processing EV battery temperature measurements for reducing wireless data transmissions to the controller 110 for extending battery life between battery replacement and / or battery recharge. End unit alarms, for example, flashing light, buzzer, and the like, for providing an end unit alarm such that an operator can readily identify a parked EV determined susceptible to an impending thermal runaway.

[0053] The controller 110 may include an operator console 112 having a display screen 113 for displaying the IR detector end units 120. The operator console 112 can include operator controls for operator configuration of the EV battery hot spot alarm logic 111. Operator controls can include a touch screen, and the like. Alternatively, EV battery hot spot alarm logic 111 can be configured remotely from a mobile device, for example, a smartphone, a laptop, and the like. The controller 110 can operate a flashing light 114 and / or a buzzer 116 for indicating an EV battery hot spot alarm. The controller 110 can issue EV battery hot spot alarms to an operator’s mobile device, for example, a smartphone, a laptop, and the like.

[0054] Figure 2 shows a family EV 10 includes an EV front end 11, an EV back end 12, an EV chassis 13, and an EV roof 14. The EV 10 includes a chassismounted generally horizontal EV battery 16. Some EVs 10 include a roofmounted generally horizontal EV battery 16. The EV battery 16 has a generally parallelepiped shape including a generally rectangular EV battery topside 17 and a generally rectangular EV battery underside 18. The EV battery 16 typically has a similar shape as the EV chassis 13 and is therefore typically longer than wider. Accordingly, the EV battery topside 17 and the EV battery topside 18 each constitute an outwardly facing, generally horizontal EV battery surface. The EV battery 16 can be implemented by different types of commercially available EV battery cells including inter alia cylindrical cells, prismatic cells, pouch cells, and the like.

[0055] Figure 3 shows an exemplary chassis mounted EV battery 16 having the following dimensions: Width W = 1.2 m, Length L = 3 m, and Ride Height RH = 13 cm ground clearance. The EV batery 16 typically has a rectangular EV batery boundary 19 including an EV batery front side 21, an EV batery back side 22, an EV batery right side 23 and an EV batery left side 24. The EV 10 typically has an about 1.2 m separation between the EV front end 11 and the EV batery front side 21 and a similar separation between the EV back end 12 and the EV batery back side 22. Figure 3 also shows the EV battery 16 has developed an EV batery hot spot HS adjacent its front right comer and an exemplary EV batery cell 26.

[0056] Section 2: IR detector end units and their deployments

[0057] Figure 4 and Figure 5 correspondingly show IR detector end unit 120A and IR detector end unit 120B configured for deployment at an EV front end 11 about 1.2 m from the EV batery front side 21 as per Figure 6 and Figure 7. The IR detector end unit 120A and the IR detector end unit 120B could be equally deployed at the EV back end 12 about 1.2 m from the EV batery back side 22. The IR detector end unit 120 A and the IR detector end unit 120B have the same end unit housing 121 with an end unit top surface 122, an end unit bottom surface 123 and an end unit peripheral surface 124. The IR detector end unit 120 A and the IR detector end unit 120B both have an ON / OFF switch 126, an onboard processing module 127, a unique ID number 128, and end unit alarms 129, for example, a flashing light, a buzzer, and the like.

[0058] The IR detector end unit 120A includes a proximity sensor 131 for detecting a parked EV’s overhead presence for starting acquiring EV batery temperature measurements. The IR detector end unit 120B includes a low batery indicator 132, a touch buton 133 on its end unit botom surface 123 for automatically switching on the IR detector end unit 120B on its placement on a parking space, a magnet 134 on its end unit botom surface 123 for magnetic atachment on a metal surface, a RF transmitter 136 for enabling determination of its location and uploading data transmissions to the controller 110, and a magnetometer 137 for enabling determination of possible misalignment with respect to a parked EV. The IR detector end units 120 include multiple adjacent single pixel IR sensors depending on their specifications and the parked EVs to be monitored. Multiple adjacent single pixel IR sensors include at least two single pixel IR sensors and, in the case for monitoring a family EV, three single pixel IR sensors 141A-141C. The single pixel IR sensors 141A-141C include a central IR sensor 141 A and lateral IR sensors 14 IB and 141C on either side of the central IR sensor 141 A. The IR sensors 141A-141C correspondingly have a generally conical Sensor Field of View (SFOV) 142A-142C around a SFOV centerline 143A-143C. From the IR detector end unit 120’s point of view, the SFOV 142A’s left side overlaps the SFOV 142B’s right side and the SFOV 142A’s right side overlaps the SFOV 142C’s left side. The IR detector end units 120 have a Detector Field Of View (DFOV) 150 extending from their SFOV 142B’s left boundary to their SFOV 142C’s right boundary. The DFOV 150 monitors a surveillance area which is preferably sufficiently large such that on intended deployment of an IR detector end unit 120 with respect to a parked EV 10, the DFOV 150 monitors its entire EV battery underside.

[0059] One suitable commercially available single pixel IR sensor 141 is the Melexis MLX90614 IR Thermometer. For illustrative purposes, the EV battery hot spot detection system 100 is described based on being implemented with the Melexis MLX90614 IR thermometers. A Revision 13 data sheet published 13 September 2019 is available online at https: / / www.melexis.com / en / product / mLx90614 / digital-plug-play-IR- thermometer-to-can The Revision 13 data sheet lists the following relevant technical features: High accuracy of 0.05°C, wide object temperature range from -70°C to 380°C, and a conical 5° Field of View as shown in Figure 4 and Figure 5.

[0060] On such implementation, the IR detector end unit 120 preferably includes the IR sensors 14 IB and 141C spaced about 5 cm from the IR sensor 141 A and subtending an about 5° azimuth on opposite sides. The IR detector end unit 120 is positioned such that its SFOV centerlines 143 A- 143 C subtend an elevation angle relative to the horizontal a where a ≈ 3° (see Figure 7) such that its DFOV 150 is directed towards an EV battery underside for acquiring its EV battery temperature measurement.

[0061] Empirical testing with such an IR detector end unit placed at the front of a mock EV having a downwardly outwardly facing 50 °C hot spot of about 10 cm diameter at about 3.5 m from the IR detector end unit, the IR detector end unit detected an about 0.2°C increase in overall EV battery temperature To between two consecutive EV battery temperature measurements.

[0062] Operation of IR detector end units 120 is now described with reference to Figure 8 and Figure 9 which correspondingly show an EV battery hot spot HS1 located solely in the SFOV 142A close to the IR sensor 141 A and an EV battery hot spot HS2 located in the SFOV 142A’s and the SFOV 142B’s overlapping area and far from the IR sensor 141 A. The single pixel IR sensors 141A-141C each sense the thermal energy emitted in their respective SFOVs 142A-142C. Accordingly, the single pixel IR sensors 141A-141C each independently acquire a sequential series of single instantaneous EV battery temperature measurements of at least some of its associated parked EV’s outwardly facing, generally horizontal EV battery surface. Even in the absence of an EV battery hot spot, the single pixel IR sensors 141A-141C in all likelihood do not measure the same EV battery temperature measurement because the SFOV 142A is predominately confined to monitoring the EV battery underside 18 while the SFOV 142B and SFOV 142C extend widthwise beyond the EV battery underside 18. Accordingly, the IR sensors 141A-141C in all likelihood measure slightly different EV battery temperature measurements typically in the order of less than 0.2°C.

[0063] In the case of Figure 8’s EV battery hot spot HS1, the single pixel IR sensor 141 A senses more thermal energy than the single pixel IR sensors 14 IB and 141C and accordingly the single pixel IR sensor 141 A would acquire a higher EV battery temperature measurement than the single pixel IR sensors 141B and 141C. In the case of Figure 9’s EV battery hot spot HS2, the single pixel IR sensor 141 A and the single pixel IR sensor 14 IB sense more thermal energy than the single pixel IR sensor 141C and accordingly would acquire a higher EV batery temperature measurement than the single pixel IR sensor 141C. In this regard, the single pixel IR sensors 141A-141C do not detect EV batery hot spots per se but rather they sense the additional thermal energy emited by a malfunctioning EV batery cell as it uncontrollably overheats which in turn translates to correspondingly higher EV batery temperature measurements.

[0064] For illustrative purposes, the EV batery hot spots HS1 and HS2 are depicted as having the same size and the EV batery hot spot HS 1 being closer to the single pixel IR sensor 141 A than the EV batery hot spot HS2. Assuming the EV batery hot spots HS1 and HS2 have the same IR radiation fluence, the single pixel IR sensor 141 A would sense more thermal energy being emited from the EV batery hot spot HS 1 than from the EV batery hot spot HS2 because the former is closer than the later. Accordingly, the single pixel IR sensor 141 A would acquire a higher EV batery temperature measurement on occurrence of the EV batery hot spot HS 1 than the EV batery hot spot HS2 notwithstanding that the hot spots are the same size and have the same IR radiation fluence.

[0065] In the case of the IR detector end unit 120 A, its onboard module 127 provides its single pixel IR sensors 141A-141C’s EV batery temperature measurements of its monitored parked EV to the controller 110 for determining whether it is being charged and whether its EV batery is susceptible to an impending thermal runaway.

[0066] In the case of the IR detector end unit 120B, its onboard module 127 determines whether its monitored parked EV is being charged and whether its EV batery is susceptible to an impending thermal runaway. In an instance its onboard module 127 determines that a parked EV is susceptible to an impending thermal runaway, it preferably activates the end unit alarms 129 as a precautionary measure notwithstanding that the controller 110 has not verified its determination is a true indication of an impending thermal runaway and not a false alarm. Thereafter, the IR detector end unit 120B’s onboard module 127 uploads data transmission to the controller 110 for processing. IR detector end unit 120 A and IR detector end unit 120B preferably include a temperature sensor for measuring ambient temperature. In this regard, increasing and decreasing ambient temperatures typically equally affect all IR detector end units 120A and all IR detector end units 120B to the same extent and their single pixel IR sensors 141A-141C to the same extent. Ambient temperature can be taken into consideration for initially determining whether a parked EV is being charged and subsequently determining whether its EV battery is susceptible to an impending thermal runaway.

[0067] IR detector end units 120 can be designed to take into consideration several factors including inter alia a parked EV to be monitored, an intended deployment of an IR detector end unit relative to a parked EV, and the like. Figure 10 and Figure 11 show an IR detector end unit 120 deployed alongside a parked EV 10. Figure 12 and Figure 13 show an IR detector end unit 120 deployed centrally under a parked EV 10.

[0068] EV battery hot spot detection systems 100 can be designed for monitoring a roof-mounted EV battery, for example, in the case of an electric bus, in which case its EV battery topside constitutes its outward facing EV battery surface. Its IR detector end units can be designed to be downwardly directed from above a parked EV to monitor its EV battery topside. EV battery hot spot detection systems 100 can be designed to monitor an EV battery topside from a parked EV front end or its EV back end, alongside a parked EV or centrally over a parked EV. An electric bus may require two spaced apart IR detector end units at its front end and its back end to monitor its EV battery due to its length compared to a family EV 10.

[0069] Section 3: Operation of EV battery hot spot detection system

[0070] Generally speaking, the EV battery hot spot detection system 100 issues a hot spot alarm regarding a parked EV irrespective of being charged or not being charged based on the premise that the likelihood that two neighboring parked EVs irrespective of being charged or not being charged simultaneously or within a relatively short predetermined time period both having a malfunctioning EV battery cell susceptible to an impending thermal runaway is statistically insignificant.

[0071] The EV battery hot spot detection system 100 is designed for issuing a hot spot alarm in the case of an EV battery being determined susceptible to an impending thermal runaway at different development rates as exemplified in Figure 14 ’s Rapid Developing Thermal Runaway (RDTR), Intermediate Developing Thermal Runaway (IDTR) and Slow Developing Thermal Runaway (SDTR) . Moreover, the EV battery hot spot detection system 100 is designed to distinguish instances of external sudden local heating conditions which may lead to neighboring parked EVs both demonstrating increases in EV battery temperatures. Examples of external sudden local heating conditions include inter alia strong sunlight between clouds, hot exhaust fumes from a passing motor vehicle, fans, etc.

[0072] Parked EVs can have different EV battery temperature profiles depending on individual circumstances as follows:

[0073] Recently parked EVs typically have higher EV battery temperatures than parked EVs which have been parked for some time. An IR detector end unit’s multiple single pixel IR sensors would acquire decreasing EV battery temperature measurements of a recently parked EV until its EV battery temperature measurements would be substantially equal to its neighboring parked EVs which had been parked for some time. In the case of a recently parked EV, a developing EV battery hot spot is highly distinctive because one single pixel IR sensor of an IR detector end unit’s multiple IR sensors would acquire increasing EV battery temperature measurements compared to its other single pixel IR sensors acquiring decreasing EV battery temperature measurements.

[0074] Charging parked EVs typically leads to increasing EV battery temperatures. The rate of increasing EV battery temperatures depends on a number of factors, for example, charge rate, EV battery type, the battery charge level, and the like. Also, the rate of increasing EV battery temperature is typically non uniform, namely, different areas of an EV battery having different rates of increasing EV battery temperature. Charging parked EVs can be identified by an IR detector end unit’s multiple single pixel IR sensors each acquiring increasing EV battery temperature measurements. In the case of a parked EV being charged, a developing EV battery hot spot is distinctive because one single pixel IR sensor of an IR detector end unit’s multiple IR sensors would typically acquire EV battery temperature measurements increasing at a faster rate compared to its other single pixel IR sensors. The increasing rate of the other single pixel IR sensors’ EV battery temperature measurements are taken into consideration on determining whether the single pixel IR sensor acquiring the increasing EV battery temperature measurements at the fastest rate is sufficiently fast to determine that a parked EV’s EV battery is susceptible to an impending thermal runaway.

[0075] The EV battery hot spot detection system 100 is preferably designed to concurrently run three moving window tests on each sequential series of single instantaneous EV battery temperature measurements of an IR detector end unit’s multiple single pixel IR sensors. The three moving window tests are designed to accommodate the considerable variance in development rates of a malfunctioning EV battery cell towards an impending thermal runaway. Each moving window test renders a positive moving window test result on counting a predetermined at least minimum number of a predetermined at least minimum temperature increments during a predetermined number of last consecutive EV battery temperature measurements.

[0076] Figure 15 shows a table listing exemplary parameters for three moving window tests as follows: Short Moving Window Test (SMWT) for early detecting a rapid developing thermal runaway. Intermediate Moving Window Test (IMWT) for early detecting an intermediate developing thermal runaway. And Long Moving Window Test (LMWT) for early detecting a slow developing thermal runaway. The SMWT, the IMWT and the LMWT are typically configured to render positive moving window test results in the Figure 14 graph sections correspondingly denoted A, B and C to provide ample time for corrective action to be taken before an impending thermal runaway. The total temperature increment for the three moving window tests can be the same, for example, 0.75°C. Alternatively, the three moving window tests can have different total temperature increments. EV battery temperature measurements are typically taken, say, every 20 seconds. The SMWT requires a minimum temperature increment 0.375°C for being counted towards a positive SMWT result requiring at least two 0.375°C minimum temperature increments in the last three consecutive EV battery temperature measurements. The IMWT requires a minimum temperature increment 0.25°C for being counted towards a positive IMWT result requiring at least three 0.25°C minimum temperature increments in the last 15 consecutive EV battery temperature measurements. The LMWT requires a minimum temperature increment 0.15 °C for being counted towards a positive LMWT result requiring at least five 0.15°C minimum temperature increments in the last 30 consecutive EV battery temperature measurements. Depending on the time intervals between consecutive EV battery temperature measurements, the SMWT typically has a 1 minute to 2 minute test period, the IMWT typically has a 2 minute to 7 minutes test period, and the LMWT typically has a 4 minute to 15 minutes test period.

[0077] Turning now to Figure 16 to Figure 19, Figure 16 shows consecutive EV battery temperature measurements resulting in a positive SMWT result, Figure 17 shows consecutive EV battery temperature measurements resulting in a positive IMWT result, Figure 18 shows consecutive EV battery temperature measurements resulting in a positive LMWT result, and Figure 19 shows consecutive EV battery temperature measurements simultaneously resulting in a positive SMWT result, a positive IMWT result, and a positive LMWT result. Figure 16 to Figure 19 have the following six columns:

[0078] Column 1: Temperature measurement number

[0079] Column 2: Temperature measurements To °C

[0080] Column 3: Delta To = To (t) - To(t-l)

[0081] Column 4: SMWT counter

[0082] Column 5 : IMWT counter

[0083] Column 6: LMWT counter Figure 16 significant EV battery temperature measurements resulting in Temperature measurement No. 35’s positive SMWT result are as follows:

[0084] EV battery temperature measurement No. 33 ’s 0.42°C increments the SMWT counter to 1, the IMWT counter to 1 and the LMWT counter to 1.

[0085] EV battery temperature measurement No. 34’s 0.17°C does not increment the SMWT counter and the IMWT counter and increments the LMWT counter to 2.

[0086] EV battery temperature measurement No. 35’s 0.38°C increments the SMWT counter to 2, the IMWT counter to 2 and the LMWT counter to 3.

[0087] Figure 17 significant EV battery temperature measurements resulting in Temperature measurement No. 44’s positive IMWT result are as follows:

[0088] EV battery temperature measurement No. 33 ’s 0.42°C increments the SMWT counter to 1, the IMWT counter to 1 and the LMWT counter to 1.

[0089] EV battery temperature measurement No. 36’s 0.03°C leads to re-setting of the SMWT counter to zero after three last consecutive temperature measurements under 0.375°C.

[0090] EV battery temperature measurement No. 37’s 0.33°C does not increment the SMWT counter and increments the IMWT counter to 2 and the LMWT counter to 3.

[0091] EV battery temperature measurement No. 44’s 0.29°C does not increment the SMWT counter and increments the IMWT counter to 3 and the LMWT counter to 4.

[0092] Figure 18 significant EV battery temperature measurements resulting in Temperature measurement No. 57’s positive LMWT result are as follows:

[0093] EV battery temperature measurement No. 33’ 0.42°C increments the SMWT counter to 1, the IMWT counter to 1 and the LMWT counter to 1.

[0094] EV battery temperature measurement No. 34’s 0.17°C does not increment the SMWT counter and the IMWT counter and increments the LMWT counter to 2. EV battery temperature measurement No. 36’s 0.03°C resets the SMWT counter to 0 after three last consecutive temperature measurements under 0.375°C.

[0095] EV battery temperature measurement No. 37’s 0.33°C does not increment the SMWT counter and increments the IMWT counter to 2 and the LMWT counter to 3.

[0096] EV battery temperature measurement No. 44’s 0.23°C does not increment the SMWT counter and the IMWT counter and increments the LMWT counter to 4.

[0097] EV battery temperature measurement No. 49’s -0.04°C decrements the IMWT counter to 1 after 15 last consecutive temperature measurements under 0.25°C.

[0098] EV battery temperature measurement No. 52’s 0.12°C resets the IMWT counter to 0 after 15 last consecutive temperature measurements under 0.25°C.

[0099] EV battery temperature measurement No. 57’s 0.17°C does not increment the SMWT counter and the IMWT counter and increments the LMWT counter to 5.

[0100] Figure 19 significant EV battery temperature measurements resulting in Temperature Measurement No’s 36 positive SMWT result, positive IMWT result and positive LMWT result are as follows:

[0101] EV battery temperature measurement No. 32’s 0.26°C does not increment the SMWT counter, and increments the IMWT counter to 1 and the LMWT counter to 1.

[0102] EV battery temperature measurement No. 33’s 0.26°C does not increment the SMWT counter and the IMWT counter and increments the LMWT counter to 2.

[0103] EV battery temperature measurement No. 34’s 0.36°C increments the SMWT counter to 1, the IMWT counter to 2 and the LMWT counter to 3.

[0104] EV battery temperature measurement No. 35’s 0.16°C does not increment the SMWT counter and the IMWT counter and increments the LMWT counter to 4. EV battery temperature measurement No. 36’s 0.42°C increments the SMWT counter to 2, the IMWT counter to 3 and the LMWT counter to 5.

[0105] Figure 20 shows EV battery hot spot alarm logic 200 includes:

[0106] Step 205: Each IR detector end unit’s single pixel IR sensors simultaneously acquiring sequential series of single instantaneous EV battery temperature measurements of its monitored parked EV

[0107] Step 210: Independently testing each sequential series of single instantaneous EV battery temperature measurements of each parked EV in accordance with the SMWT, the IMWT and the LMWT

[0108] Step 215 : On the condition one of the SMWT, the IMWT and the LMWT renders a positive moving window test result for a parked EV, determine the parked EV is susceptible to an impending thermal runaway.

[0109] Step 220: Determine whether the parked EV is being charged. In the affirmative, the following step is step 225. In the negative, the following step is 230.

[0110] Step 225: Determine whether the charged parked EV is susceptible to an impending thermal runaway. In the negative, the following step is step 205. In the affirmative, the following step is step 230.

[0111] Step 230: Issue a hot spot alarm for a susceptible parked EV on the condition that, within a predetermined time period from its determination, no other parked EV is additionally determined susceptible to an impending thermal runaway.

[0112] In the case of an IR detector end unit 120A, its onboard module 127 provides its IR sensors 141A-141C’s EV battery temperature measurements to the controller 110 for determining whether its monitored parked EV is susceptible to an impending thermal runaway with the possible intermediate determination of whether it is being charged or not. On the condition there is not another parked EV of its neighboring parked EVs additionally determined being susceptible to an impending thermal runaway, the controller 110 verifies the susceptible parked EV is not a false alarm but in fact developing an impending thermal runaway. Accordingly, the controller 110 preferably activates the flashing alarm light 114 and the buzzer 116, and also the IR detector end unit 120A’s end unit alarms 129 for assisting an operator to locate the parked EV verified as being susceptible to an impending thermal runaway. Preventive action may be taken, for example, moving the susceptible parked EV to a safe location, placing a protective covering on the susceptible parked EV, and the like.

[0113] In the case of an IR detector end unit 120B, its onboard module 127 processes its IR sensors 141A-141C’s EV battery temperature measurements for determining that its monitored parked EV is susceptible to an impending thermal runaway with the possible intermediate determination of whether it is being charged or not. In the affirmative that its monitored parked EV is susceptible to an impending thermal runaway, its onboard module 127 preferably activates the end unit alarms 129 as a precautionary measure notwithstanding it may be a false alarm prior to the controller 110’s verification. Thereafter, the IR detector end unit 120B uploads its determinations to the controller 110. On the condition there is not another parked EV of its neighboring parked EVs additionally determined being susceptible to an impending thermal runaway, the controller 110 verifies the susceptible parked EV is not a false alarm but in fact developing an impending thermal runaway. Accordingly, the controller 110 preferably activates the flashing alarm light 114 and the buzzer 116. Preventive action may be taken, for example, moving the susceptible parked EV to a safe location, placing a protective covering on the susceptible parked EV, and the like. In the case of a false alarm, an operator approaches the IR detector end unit 120B and re-sets its end unit alarms 129.

[0114] Section 4: Wireless EV battery hot spot detection systems

[0115] Car carrier vessels differ from land-based carparks in several major respects as follows: First, EVs are typically much more closely packed on a car carrier deck than a land-based carpark because of the high cost of sea transportation. Second, EVs of considerably different sizes can be parked side by side on the same car carrier deck which precludes against designated parking spaces. Each loading of fresh EVs on a car carrier deck typically requires a renewed placement of IR detector end units. And third, close packing militates against convenient access for correctly placing IR detector end units with respect to their parked EVs. Moreover, an EV battery explosion on a car carrier vessel can swiftly lead to a major disaster compared to a land-based EV battery explosion which can be more easily contained and extinguished.

[0116] Figure 21 and Figure 22 show a wireless EV battery hot spot detection system 100 intended for deployment on a car carrier deck 50 but which can also be equally and advantageously deployed at a land-based car park because it precludes considerable installation before operation. The wireless EV battery hot spot detection system 100 includes the controller 110, IR detector end units 120B only, and say, four gateways 60A-60D for enabling preferably unidirection wireless communication from the IR detector end units 120B to the controller 110 to extend their battery lifetime before battery replacement / recharging compared to bi-directional wireless communication. The four gateways 60A-60D are typically located at the car carrier deck 50 ’s four comers 50A-50D.

[0117] The car carrier deck 50 is loaded with a left row of eight EVs 10A-10H, a right row of eight EVs 101- 1 OP, and two electric trucks 10Q and 10R. The EVs 10A-10H are the same EV size. The EVs 101- 10P are different sized EVs. An operator places IR detector end units 120B as shown. The IR detector end units 120B are required to be placed at specific alignments with respect to parked EVs to enable monitoring their EV batteries. The IR detector end units 120B are prone to be incorrectly placed with respect to EVs because of restricted accessibility. The operator has inadvertently misaligned IR detector end units 120B-2 and 120B-13 which will prevent them from correctly monitoring their respective EVs 10B and 10M.

[0118] The IR detector end units 120B transmit wireless information including their ID numbers, RF messages, and magnetometer measurements. The four gateways 60A-60D receive the RF messages and employ standard triangulation techniques to determine their positions for display on the operator console 112. The controller 110 determines the alignments of the IR detector end units 120B- 1-120B-20 to detect possibly misaligned IR detector end units. Misalignment is typically set at upto about 5° from an intended orientation. The operator console 112 alarms that the IR detector end units 120B-2 and 120B-13 are misaligned with respect to their neighboring IR detector end units. The operator corrects their orientation such they are correctly aligned with respect to their respective EVs.

[0119] The EV battery hot spot detection system 100 operates as described in Section 3: Operation of EV battery hot spot detection system with respect to IR detector end units 120B.

[0120] While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications, and other applications of the invention can be made within the scope of the appended claims.

Claims

CLAIMS:

1. An Electric Vehicle (EV) battery hot spot detection system for use with at least two neighboring parked EVs, each parked EV having an EV battery with an outwardly facing, generally horizontal EV battery surface, the EV battery hot spot detection system comprising: a) a multitude of IR detector end units external to the at least two neighboring parked EVs for remote acquiring EV battery temperature measurements of their outwardly facing, generally horizontal EV battery surfaces, each IR detector end unit deployed adjacent a single associated parked EV’s EV battery of the at least two neighboring parked EVs for remote acquiring its EV battery temperature measurements, each IR detector end unit including at least two adjacent single pixel IR sensors for independently acquiring a sequential series of single instantaneous EV battery temperature measurements of at least some of its single associated parked EV’s outwardly facing, generally horizontal EV battery surface, each sequential series of single instantaneous EV battery temperature measurements being independently tested in accordance with at least one moving window test for rendering a positive moving window test result on counting a predetermined at least minimum number of a predetermined at least minimum temperature increment during a predetermined number of last consecutive EV battery temperature measurements, thereby enabling determination that a parked EV of the at least two neighboring parked EVs is susceptible to an impending thermal runaway; and b) a controller for issuing a hot spot alarm for a susceptible parked EV of the at least two neighboring parked EVs on the condition that, within a predetermined time period from its determination, no other parked EV of the at least two neighboring parked EVs is additionally determined susceptible to an impending thermal runaway.

2. The system according to claim 1 wherein the at least one moving window test includes at least two moving window tests of: a short moving window test for counting large minimum EV battery temperature increments, an intermediate moving window test for counting intermediate minimum EV battery temperature increments smaller than the large minimum EV battery temperature increments, and a long moving window test for counting small minimum EV battery temperature increments smaller than the intermediate minimum EV battery temperature increments.

3. The system according to either claim 1 or 2 wherein the condition that each single pixel IR sensor of a parked EV’s associated IR detector end unit acquires increasing single instantaneous EV battery temperature measurements within a predetermined time period, thereby enables determination that a parked EV is being charged.

4. The system according to any one of claims 1 to 3 wherein an IR detector end unit’s at least two adjacent single pixel IR sensors each having a single pixel IR sensor field of view where adjacent sensor fields of view partially overlap.

5. The system according to any one of claims 1 to 4 wherein an IR detector end unit is a discrete hand portable unit with a unique ID number and includes a wireless transmitter for enabling determination of its location.

6. The system according to claim 5 wherein an IR detector end unit includes a proximity sensor for detecting presence of a parked EV for monitoring purposes, and an onboard processing module for determined the parked EV is susceptible to an impending thermal runaway and providing an operator alarm.

7. The system according to any one of claims 1 to 6 wherein an IR detector end unit is configured for externally monitoring a parked EV’s outwardly facing, generally horizontal underside battery surface.

8. The system according to any one of claims 1 to 6 wherein an IR detector end unit is configured for externally monitoring a parked EV’s outwardly facing, generally horizontal topside battery surface.

9. An IR detector end unit for use in an Electric Vehicle (EV) battery hot spot detection system according to any one of claims 1 to 8.

10. An installation including an Electric Vehicle (EV) battery hot spot detection system according to any one of claims 1 to 8 wherein the installation is configured for parking a multitude of neighboring EVs.

11. The installation according to claim 10 wherein the installation is a car carrier vessel.

12. A method for providing an EV battery hot spot alarm for use with at least two neighboring parked EVs, each parked EV having an EV battery with an outwardly facing, generally horizontal EV battery surface, the method comprising the steps of: a) providing a multitude of IR detector end units external to the at least two neighboring parked EVs for remote acquiring EV battery temperature measurements of their outwardly facing, generally horizontal EV battery surfaces, each IR detector end unit deployed adjacent a single associated parked EV’s EV battery of the at least two neighboring parked EVs for remote acquiring its EV battery temperature measurements, each IR detector end unit including at least two adjacent single pixel IR sensors for independently acquiring a sequential series of single instantaneousEV battery temperature measurements of at least some of its single associated parked EV’s outwardly facing, generally horizontal EV battery surface, each sequential series of single instantaneous EV battery temperature measurements being independently tested in accordance with at least one moving window test for rendering a positive moving window test result on counting a predetermined at least minimum number of a predetermined at least minimum temperature increment during a predetermined number of last consecutive EV battery temperature measurements, thereby enabling determination a parked EV of the at least two neighboring parked EVs is susceptible to an impending thermal runaway; and b) providing a controller for issuing a hot spot alarm for a susceptible parked EV of the at least two neighboring parked EVs on the condition that, within a predetermined time period from its determination, no other parked EV of the at least two neighboring parked EVs is additionally determined as being susceptible to an impending thermal runaway.

13. The method according to claim 12 wherein the at least one moving window test includes at least two moving window tests of: a short moving window test for counting large minimum EV battery temperature increments, an intermediate moving window test for counting intermediate minimum EV battery temperature increments smaller than the large minimum EV battery temperature increments, and a long moving window test for counting small minimum EV battery temperature increments smaller than the intermediate minimum EV battery temperature increments.

14. The method according to either claim 12 or 13 wherein the condition that each single pixel IR sensor of a parked EV’s associated IR detector end unit acquires increasing single instantaneous EV battery temperature measurementswithin a predetermined time period, thereby enables determination that a parked EV is being charged.

15. The method according to any one of claims 12 to 14 wherein an IR detector end unit’s at least two adjacent single pixel IR sensors each having a single pixel IR sensor field of view where adjacent single pixel IR sensor fields of view partially overlap.

16. The method according to any one of claims 12 to 15 wherein an IR detector end unit is a discrete hand portable unit with a unique ID number and includes a wireless transmitter for enabling determination of its location.

17. The method according to claim 16 wherein an IR detector end unit includes a proximity sensor for detecting presence of a parked EV for monitoring purposes, and an onboard processing module for determining a parked EV is susceptible to an impending thermal runaway and providing an operator alarm.

18. The method according to any one of claims 12 to 17 wherein an IR detector end unit is configured for externally monitoring a parked EV’s outwardly facing, generally horizontal underside battery surface.

19. The method according to any one of claims 12 to 17 wherein an IR detector end unit is configured for externally monitoring a parked EV’s outwardly facing, generally horizontal topside battery surface.

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