Method and device for physically contactlessly identifying a safety-critical condition of an electrochemical energy accumulator

Abstract

The invention relates to a method and a device (1) for physically contactlessly identifying a safety-critical condition of at least one electrochemical energy accumulator which is arranged in a housing, the method comprising the steps: a) contactlessly measuring and storing at least one current value of the temperature at at least one location on the exterior of the housing by means of a sensor (7), and comparing the measured current value with a specified limit value for the temperature for this location in an analysis unit (9); wherein b) when the limit value is exceeded, a warning signal is output, and c) when the current value lies below the limit value, a temperature gradient for this location is determined; wherein d) a warning signal is also output when the temperature gradient is greater than or equal to a limit gradient value, and e) when the temperature gradient is smaller than the limit gradient value, steps a) to e) are carried out again.

Description

[0001] Method and device for the physical contactless determination of a safety-critical state of an electrochemical energy storage device

[0002] The invention relates to a method for the physically contactless determination of a safety-critical state of at least one electrochemical energy storage device arranged in a housing, according to the preamble of claim 1, and to a portable device for carrying out the method, according to the preamble of claim 11.

[0003] Many systems with batteries or accumulators have temperature monitoring devices during charging or discharging to detect abnormal operating conditions and initiate appropriate countermeasures. In electric vehicles, for example, such monitoring devices are integrated into the vehicle's electronics. These systems cannot be used by emergency personnel for external monitoring, especially in emergencies such as accidents, fires, or similar situations. Furthermore, the monitoring devices integrated into the vehicle can be damaged by accidents or fires, rendering their functionality ineffective.

[0004] In these cases, it is particularly important to be able to determine quickly and easily whether one or more cells in the vehicle battery are thermally damaged. Since, for example, destroyed separators result in an exothermic process, propagation can result in numerous exothermic processes occurring in rapid succession, thus heating the battery casing within a certain period of time. On the one hand, the extent of damage caused by propagation should be kept to a minimum, but on the other hand, the goal is to avoid extinguishing a safe battery as reliably as possible, which could cause collateral damage and require a large amount of water.

[0005] In an emergency, the heating of areas over a longer period of time cannot be determined using a handheld thermal camera because the temperature must be read by a person, which would tie up an emergency worker urgently needed for firefighting or rescue operations. Furthermore, since only point-by-point readings are possible, no evaluations can be made for larger areas. Furthermore, documenting the times of measurements by an emergency worker is problematic because of the inaccuracies, particularly in challenging situations. The change in temperature over time must then be calculated and interpreted for each measuring point in a separate step. Furthermore, a critical absolute temperature cannot be defined because the influence of the vehicle and the environment is too great.

[0006] US10953250B2 discloses a fire-fighting arrangement for a stationary energy storage system, which, in addition to an electrochemical energy storage device, also has at least one fire-fighting device in a protective housing. A stationary image recognition arrangement is positioned outside the protective housing. This arrangement includes an evaluation unit that can determine whether there is a fire in the housing from the image material. In this case, the fire-fighting device is activated until the image recognition arrangement can conclude that the emergency has ended.

[0007] A method for responding to a critical fire condition in a motor vehicle is disclosed in US10960246B2. A battery temperature of at least one battery of the motor vehicle is continuously detected internally by means of at least one temperature sensor located in or on the battery. Based on the continuously detected battery temperature and a check to determine whether the determined temperature change exceeds a predetermined limit value that defines a critical fire condition, at least one vehicle function is activated to implement a protective measure and / or warning measure.

[0008] CN102568146A discloses an early fire warning and extinguishing system that operates based on an infrared thermal image. An infrared thermal imaging camera is connected to an image analysis controller, which controls a fire warning and linkage controller. This controller is connected to the controller of the monitored device and to a fire extinguishing device. As part of the thermal imaging camera's image analysis, the temperature data is analyzed. The infrared thermal image is divided into several areas according to the temperature data, and the area in which the normal operating temperature is exceeded is selected as the target area. For this target area, the difference between the temperature of the target area and the normal operating temperature of the monitored device is calculated in a temperature comparison sub-module, and a fire alarm signal and / or a fire extinguishing control signal is sent.Furthermore, a change curve of the difference between the target field temperature and the ambient temperature is determined within a predetermined time. If the change curve continues to rise and the difference is greater than the first temperature threshold, this is taken as an indication of a fire in the target field. If the curve continues to rise and the difference is between the first and second temperature thresholds, this is evaluated as a sign of a potential fire. Finally, if the curve remains stable and the difference is less than the second temperature threshold, and the first temperature threshold is not less than the second temperature threshold, the system considers there to be no fire in the target field.

[0009] The object of the present invention was to overcome the disadvantages of the prior art and to provide a device and a method by means of which a continuous dynamic monitoring of an electrochemical energy storage device, in particular a drive battery for electric vehicles, for safety-critical conditions can be carried out automatically and without permanent user involvement.

[0010] This object is achieved by a device and a method according to the claims.

[0011] The method according to the invention comprises the steps of a) contactless recording and storing at least one instantaneous value of the temperature of at least one point on the outside of the housing, and comparing the recorded instantaneous value with a predetermined temperature limit for this point, wherein b) a warning signal is output if the limit is exceeded, and c) a temperature gradient is determined for this point if the instantaneous value is below the limit, wherein d) a warning signal is also output if the temperature gradient is greater than or equal to a gradient limit, and e) steps a) to e) are repeated if the temperature gradient is less than the gradient limit.

[0012] By means of the observations carried out according to the invention on the surface of the housing of an energy storage device and by means of the corresponding evaluation, conclusions can be drawn automatically about the state of the energy storage device itself, in particular about escalating cells or an entire escalating battery.

[0013] An advantageous variant of the method provides that f) instantaneous temperature values ​​are recorded at several points on the outside of the housing, wherein if the temperature limit is exceeded at at least one point a warning signal is issued, and wherein g) if the instantaneous value is below the limit at all points the respective temperature gradient between the instantaneous values ​​recorded at the respective point is determined for all points, h) if the temperature gradient is greater than or equal to a gradient limit at at least one point a warning signal is issued, and i) if the temperature gradient is less than the gradient limit at all points steps f) to i) are repeated.

[0014] It is preferred that the instantaneous values ​​of a first group of preferably adjacent locations are processed separately from the instantaneous values ​​of one or more further groups of other locations, which are at least for the most part spatially located outside the first group.

[0015] Preferably, the first group includes the location with the highest instantaneous value and / or with the largest temperature gradient.

[0016] A further variant of the method is characterized in that several groups are formed according to different zones or modules of the energy storage system.

[0017] At least one of the further groups may comprise a concentric ring around one or more inner group(s).

[0018] Another method variant according to the invention provides that the gradient limit value for at least the point with the highest value is adapted as a function of the course of the instantaneous values, preferably starting with the first detected instantaneous value, and preferably also as a function of the temperature limit value, before each new detection of an instantaneous value.

[0019] It is advantageous if the gradient limit value is determined as a function of the last recorded instantaneous value and a threshold value for the next temperature value to be recorded, whereby the threshold value is determined as a function of the course of the instantaneous values, preferably back to the first recorded instantaneous value at this point, and preferably also as a function of the temperature limit value. A further preferred procedure is that the gradient limit value or threshold value is determined for each point based on the instantaneous values ​​at the point with the highest temperature and / or with the highest gradient.

[0020] Advantageously, the ambient temperature of the respective location is recorded at least before the threshold value is determined and the threshold value is adjusted depending on the ambient temperature.

[0021] A further embodiment provides for the specified limit value and / or the gradient limit value to be adjusted depending on parameters that are characteristic of the respective monitored electrochemical energy storage device. This measure allows a more precise determination of the escalation requirement based on specific characteristics of the energy storage device, with the characteristics preferably being derived from manufacturer specifications or being directly derived from such manufacturer specifications.

[0022] In one possible embodiment, at least the detection at at least one location on the outside of the housing is supported by parameters of the electrochemical energy storage device that are characteristic of the respective monitored electrochemical energy storage device, taking into account the structural shape and / or arrangement of the electrochemical energy storage device in the housing. This measure offers the advantage that the method can be limited to those areas where the energy storage device is actually located, thus reducing or optimizing the measurement range.

[0023] The object posed at the outset is also achieved by a portable device for the physically contactless determination of a safety-critical state of at least one electrochemical energy storage device which is arranged in a housing, at least comprising at least one housing, operating elements and / or interfaces for user inputs, at least one output unit for at least one warning signal, and a) at least one sensor for the at least intermittent contactless detection of at least one instantaneous value of the temperature of at least one point on the outside of the housing, b) at least one storage unit which is designed to store the instantaneous values, their time stamp, a predefinable temperature limit value and a gradient limit value, b) at least one evaluation unit which is designed to carry out the method according to at least one of the preceding paragraphs.

[0024] The system makes it possible, for example, to detect an escalating battery before the fire propagates into an uncontrollable situation. At the same time, it prevents the unnecessary extinguishing of intact batteries.

[0025] Preferably, at least one sensor is a thermal imaging camera. Cameras with a wide aperture angle are particularly preferred, allowing the entire housing to be observed with a small number of lenses and / or from the shortest possible distance.

[0026] Preferably, an optical alignment aid is integrated into or on the device. This design allows for simplified positioning of the device for emergency personnel, as its detection range can be signaled to a user. The alignment aid can be displayed on a monitor or projected onto the housing, for example, using means provided on the device.

[0027] In a possible further development, it can be provided that manufacturer-specific parameters for electrochemical energy storage devices can be stored in the storage unit. This is advantageous because different limit values ​​can be taken into account for the energy storage devices, depending on the manufacturer's specifications, thus ensuring more precise measurements. Furthermore, the shape and size of the energy storage device can be taken into account, allowing the measurement ranges to be adjusted. In a particularly advantageous embodiment, the alignment aid can be adapted with respect to these parameters, e.g., to the shape of the energy storage device.

[0028] Furthermore, it can be provided that the alignment and / or position of the device relative to the electrochemical energy storage device can be stored in the storage unit. This can be done through user input, but can also be determined by the device itself. This again offers advantages such as a possible improvement in the alignment aid and optimized control of the measurement process.

[0029] For a better understanding of the invention, it is explained in more detail with reference to the following figures. They show, in highly simplified, schematic representations:

[0030] Fig. 1 is a schematic representation of a preferred application of a device according to the invention and its basic functional units;

[0031] Fig. 2 is a schematic representation of the essential electronic components of the device according to the invention and their connections;

[0032] Fig. 3 is a schematic representation of the functional principle of the device in use according to Fig. 1;

[0033] Fig. 4 block diagrams of the method according to the invention, wherein Fig. 4a represents the simplest variant and Fig. 4b a variant with adaptation of the gradient limit value;

[0034] Fig. 5 shows a schematic representation of the functional principle using clustering.

[0035] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the position information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these position information must be applied analogously to the new position in the event of a change in position.

[0036] The term “in particular” is understood below to mean that it may be a possible more specific embodiment or more detailed specification of an object or a method step, but does not necessarily have to represent a mandatory, preferred embodiment of the same or a mandatory procedure.

[0037] Figure 1 shows a portable device 1 according to the invention, which is placed near an electric vehicle 2 by emergency personnel in an emergency, specifically to monitor the battery 3 used to power the vehicle 2 and to detect any safety-critical condition. Of course, the device 1 can be used to monitor any electrochemical energy storage device arranged within a housing and not directly visible or accessible.

[0038] The device 1 according to the invention comprises at least one housing, to which operating elements 4 and / or interfaces for user inputs are provided or can be coupled, for example to call up functions, enter parameters, or the like. Furthermore, at least one output unit 5 for at least one optical and / or acoustic warning signal is integrated, as well as possibly a monitor 6, among other things for displaying the entered values, for displaying a menu for the functions, for displaying the field of view of the sensors, etc. Furthermore, the warning signal can also be provided haptically or tactilely, for example by means of vibrations. Furthermore, at least one sensor 7 is provided for at least intermittently and contactlessly detecting at least one instantaneous temperature value at at least one point on the outside of the housing of the electrochemical energy storage device, in particular in the example shown on the outside of the body, ora supporting structure such as the chassis of the vehicle 2 and / or the immediately adjacent environment, the temperature of which changes proportionally due to the effect of the temperature of the battery 3.

[0039] The instantaneous values ​​can be recorded discontinuously at specific time intervals, resulting in a smaller amount of data to be processed. The intervals between the instantaneous values ​​can also be adjusted if necessary, for example, to ensure shorter-term temperature recording at high temperatures and / or gradients for increased accuracy in monitoring the electrochemical energy storage system. Of course, instead of recording temperatures and / or gradients intermittently, i.e. discontinuously, continuous recording is also possible, which provides very large amounts of data while also offering the highest level of accuracy.

[0040] At least one of the sensors 7 can be a thermal imaging camera, preferably with the largest possible aperture angle. This is advantageous in order to be able to monitor the entire battery 3 and all its cells 3a with the smallest possible number of sensors 7, despite being positioned as close as possible to the vehicle 2. At least one temperature detector is present, which is configured to thermographically determine at least a first temperature value of at least one first measuring field of any size, which can also be a single, narrowly defined measuring point, with respect to the at least one housing at several points in time. Further advantageously integrated or connectable sensors can record the orientation and position of the device 1, the ambient temperature, and other chemical-physical values, for example gases characteristic of certain conditions.

[0041] In order to enable the user to quickly and easily align the sensors 7 correctly to the required or desired area, an optical alignment aid is advantageously provided, for example a grid visible on the monitor 6, a crosshair, a laser aiming device or the like.

[0042] As shown in Fig. 2, the device 1 further comprises at least one storage unit 8 for storing the temperature values ​​of the at least one measuring field or measuring point determined thermographically by means of the temperature detector. The storage unit 8 is preferably designed to store the instantaneous values, their time stamp, a predeterminable temperature limit, and a gradient limit.

[0043] The term temperature value can include a temperature field, an instantaneous point value, a maximum value in a certain time interval, etc., in particular also results of calculations from several values.

[0044] Finally, the device 1 is equipped with at least one evaluation unit 9, which is connected to the storage unit 8, the operating elements 4, and the output unit 5. The evaluation unit 9 receives the sensor signals and / or retrieves the stored data, processes them, and thus monitors the temporal progression of the temperature of the battery 3 indirectly via the temperature of the relevant points on the vehicle 2. If a certain temperature or a certain temperature gradient is exceeded, the evaluation unit 9 controls the output unit 5 to generate a warning and, if necessary, also displays a corresponding warning message on the monitor 6.

[0045] This means that no emergency personnel that are more urgently needed for other tasks are tied up in monitoring, and errors in interpretation when determining the thermal conditions are also prevented.

[0046] An integrated data interface, preferably for wireless data transmission such as via GSM, allows the temperature curve(s) to be logged in an operations center, which then preferably also receives the warning messages to ensure double security in case the warning messages are not registered at the emergency site. Furthermore, after receiving the warning messages, the operations center can independently support the emergency services on site by initiating the next steps. The messages from device 1 can also be transmitted to specific users, such as the operations manager, via the data interface. Advantageously, a unique identifier for the respective device is transmitted with each data transmission, preferably also a position report.Furthermore, multiple devices 1 can be provided, each measuring the same or different electrochemical energy storage devices, which advantageously allows for a clear assignment of the warning signal to the respective device. The data interface can also be used to control the device 1 via wireless units, to make inputs via it, or to use the wireless unit as an external display unit. Mobile phones, tablets, or the like can be used as such units for remote control and query.

[0047] In principle, the storage unit 8 and / or the evaluation unit 9 could also be arranged separately from the unit that monitors the electrochemical energy storage device, for example, the battery 3 of a vehicle 2. This provides better protection for these valuable and sensitive components against all thermal and / or mechanical stresses at the emergency site. On the other hand, it is usually desirable to keep data transfer as low as possible and to ensure interference-free transmission over the shortest possible distances, which makes it advantageous to integrate the storage unit 8 and the evaluation unit 9 together with the other components 4, 5, 6, and 7 into a jointly manageable, portable, and positionable device.

[0048] Advantageously, the device 1 with all its systems such as sensors, evaluation, etc. is designed to be independent of an external power supply and is preferably supplied with the necessary energy to operate all systems via batteries, rechargeable accumulators or integrated power generators.

[0049] Furthermore, the device 1 can, for example, have means for distance measurement to determine the distance between the device 1 and the housing or the electrochemical energy storage device. For example, the distance can be included in the method for determining the state of the electrochemical energy storage device. Furthermore, the device can be configured such that manufacturer-specific parameters for electrochemical energy storage devices are stored in the device, preferably in the storage unit. Using the parameters, the method can be optimized in such a way as to obtain, for example, specific maximum temperature values ​​for the respective energy storage device.

[0050] Furthermore, it can be provided that the orientation and / or position of the device 1 relative to the electrochemical energy storage device or its housing can be entered in the device. For example, from which side the energy storage device is measured. Optionally, rough orientations can be provided / stored, which can be selected by a user.

[0051] Furthermore, in a further development, the device can be designed to determine the position of a housing or vehicle to be detected by means of optical sensors, e.g. to determine on the basis of comparison images whether the vehicle is being measured from the front, rear, top, bottom or a right or left side.

[0052] Preferably, the device, as shown in Fig. 1, is placed on the ground next to a vehicle 2 to be monitored. Adjustable feet, tripod-like substructures, or the like may be provided for uneven or inclined surfaces in order to optimally align the device 1 with respect to the vehicle 2, both in terms of the barrier-free detection field for the battery 3 and the inclination around three orthogonal axes. As shown in the schematic representation in Fig.3, the image obtained from, for example, thermal imaging cameras as sensors 7 is a distorted projection, but the point 10 of maximum temperature of battery 3 of vehicle 2, the area 11 of slightly lower temperature around point 10, as well as the even cooler area 12 of the underside of the body of vehicle 2 can be clearly and unambiguously identified and recorded in a dimension that allows a good evaluation of the temperatures of point 10 and areas 11 and 12 with regard to the maximum values ​​as well as the temporal behavior.

[0053] In this regard, Fig. 3 schematically shows the thermal image 14 determined by the temperature detection unit, as well as a theoretical image of the vehicle 2 if the vehicle 2 were viewed from below. As can be seen, the thermal image 14 is compressed or reduced in size compared to the view from below due to the arrangement of the device 1 relative to the vehicle 2; however, the relationship between the individual regions and their temperature profile remains the same.

[0054] The method according to the invention for the physically contactless determination of a safety-critical state of at least one electrochemical energy storage device arranged in a housing will now be explained in more detail. This method is preferably in the form of an algorithm or computer program product and is implemented in the evaluation unit 9 of the device 1. The basic variant of this method is shown in Fig. 4a in the form of a flowchart.

[0055] At least one sensor 7 is used to contactlessly detect and store at least one instantaneous temperature value of at least one location on the outside of the housing, i.e., preferably on the vehicle structure immediately adjacent to the battery 3. Preferably, the location 10 with the maximum temperature is determined and selected as the location for the subsequent method steps. In the evaluation unit 9, the instantaneous value detected during the respective measurement is compared with a predetermined temperature limit for this location, which is entered into the memory unit 8 via the operating elements 4 or permanently written into the memory unit.

[0056] As schematically illustrated in Fig. 3, a device 1 placed on the ground next to a vehicle 2, whose sensors 7 are intended to detect, in particular, the underside of the body of the vehicle 2, results in a perspectively compressed image of the floor panel of the vehicle 2 and the adjacent side of the vehicle 2, thus also of the ground beneath the vehicle 2. However, the temperature values ​​can still be easily recorded, as can the temperature distribution, in particular along the length of the vehicle 2, and also the temporal progression of the temperature values.

[0057] If the limit value is exceeded, a warning signal is issued by the warning device 5. For emergency personnel, this typically means that the battery has escalated or is about to do so, and that appropriate countermeasures must now be taken. In this case, monitoring can then be terminated. If the current value for the measured temperature does not reach this limit at any point on the vehicle 2, monitoring continues, and the evaluation unit 9 determines a temperature gradient for the location in question.

[0058] The next step involves comparing this determined temperature gradient with a gradient limit value entered in the memory unit 8 or predefined. If the current temperature gradient is greater than or equal to the limit value, a warning signal is also issued. For emergency responders, this typically also means that the battery is about to escalate, and that appropriate countermeasures must now be taken and monitoring can be terminated.

[0059] If necessary, different signals are provided for exceeding the temperature limit and the temperature gradient limit.

[0060] If the temperature gradient is less than the gradient limit value, the steps described are repeated after a period of time that is predefined or can be predefined via the operating elements 4, starting with the determination of the new instantaneous value of the temperature at the warmest point 10 on the housing for the electrochemical energy storage device, which is now available after the expiration of the period of time.

[0061] Advantageously, since the individual cells 3a of the battery 3 can develop differently, also depending on the ambient conditions, in particular in the event of a vehicle fire, the sensors 7 with a large detection range record instantaneous temperature values ​​at several points on the outside of the housing, i.e. the areas of the body of the vehicle 2 immediately adjacent to the battery 3, and a warning signal is issued if the temperature limit is exceeded at at least one point. Here, it is of course possible to specify different limit values ​​for different points. It is also possible to determine temperature values ​​at many points distributed over a large measuring field and to use these characteristic values, which are calculated from experience and / or using predefined algorithms, to assess the condition of the electrochemical energy storage device.

[0062] In a similar manner as previously explained, for all locations considered, for example location 10 and areas 11 and 12, the respective temperature gradient between the instantaneous values ​​recorded at the respective location is determined if the instantaneous temperature values ​​are everywhere below the universal or local limit value.

[0063] Again, if the temperature gradient is greater than or equal to a gradient limit value at at least one location, a warning signal is issued, whereby a local limit value for each individual location or a universal limit value that is the same across all locations can be specified with regard to the temperature gradient.

[0064] The consequences after the warning signal is issued are the same as described above, and it is also the same that if the temperature gradients at all points are less than the gradient limit, the described process steps are carried out at all points after a specified or specifiable period of time has elapsed.

[0065] Since the temperature and the temperature gradient are typically preferably determined at several locations on the housing of the electrochemical energy storage device, a variant of the method is often advantageous in which the instantaneous values ​​of a first group of locations are processed separately from the instantaneous values ​​of one or more further groups of other locations.

[0066] An advantageous variant for forming clusters is to use temperature as a criterion. Thus, as shown in Fig. 5 as an example, a first group, a first cluster CI, can contain the point with the highest instantaneous value as well as those points that lie within a predetermined spatial distance and / or within a predetermined temperature difference from the point with the highest instantaneous temperature value. In addition to or as an alternative to temperature, the temperature gradient can also be used as an alternative or supplementary criterion for forming groups, whereby a first group, a first cluster CI, can also contain the point with the highest value of the temperature gradient as well as those points that lie within a predetermined spatial distance and / or within a predetermined difference in the gradient values. Further groups orClusters C2, C3 are then formed by the locations located in further temperature intervals or intervals of the temperature gradient values ​​around the first group, which typically results in clusters arranged in a ring around the first, then innermost group. Such an arrangement can also be created by the algorithm implemented in the evaluation unit 9 device 1, which can be designed to create at least one of the further groups as a possibly concentric ring around one or more inner group(s) and thus combine the corresponding temperature detection points on the housing of the electrochemical energy storage device.Preferably, with appropriate alignment of the device 1, a cluster formation can be specified via the algorithm and models of the temperature distribution in electrochemical energy storage devices, such as preferably the batteries in electric vehicles, in which several groups are formed corresponding to different zones or modules of the energy storage device.

[0067] Forming clusters in this way can be advantageous in order to be able to observe and evaluate the temperature development of the environment and the vehicle separately. In the case of thermal imaging cameras, the mean value across the entire field of view of the sensor could be used as the cluster criterion. For example, cluster CI can comprise the battery 3, i.e., the location 10 with the highest instantaneous value and / or with the greatest temperature gradient, as well as the immediately surrounding area 11. A second cluster C2 typically comprises the rest of the vehicle underside, i.e., area 12 in Fig. 3, and a third cluster C3 the immediate surroundings 13 of the underside of the vehicle 2, the temperature values ​​of which naturally also influence the temperature development of the battery 3 in the vehicle 2.

[0068] If the location with the highest temperature does not coincide with the location with the largest temperature gradient, the first cluster CI is preferably spatially placed or extended in such a way that it includes both locations.

[0069] In connection with the group or cluster formation, various procedural variants are possible, such as the calculation of the temperature gradient over time for each cluster as a whole, across all individual temperature determination points included in the respective group.

[0070] It is also often important to differentiate all locations with a temperature higher than the ambient temperature from all locations with a lower temperature and to form clusters using this criterion. Local maxima are then determined in the group(s) with a temperature higher than the ambient temperature. A further advantageous variant of the method according to the invention provides that the gradient limit value relevant for assessing the risk of escalation of the electrochemical energy storage device is adjusted for at least the location with the highest value depending on the course of the instantaneous values ​​of the gradient before each new recording of an instantaneous value. A corresponding flow diagram is shown in Fig. 4b. This makes it possible to respond to changing ambient conditions that influence the temperature profile on or in the housing, for example the body of the vehicle 2 containing the battery 3.Preferably, the entire history since the start of monitoring the electrochemical energy storage device is used to calculate the gradient limit, i.e., starting with the first recorded instantaneous value, and preferably also depending on the typically fixed temperature limit. An optimal variant is one in which this procedure is selected for at least the point with the highest value of the gradient limit.

[0071] In particular, it is preferred if the algorithm implemented in the evaluation unit 9 calculates the gradient limit value as a function of the last recorded instantaneous temperature value at the respective location on the housing and a threshold value for the next temperature value to be recorded at precisely this location. The respective threshold value is preferably not permanently stored, but is always newly determined by an algorithm of the evaluation unit 9 determining the threshold value depending on the course of the instantaneous temperature values. Preferably, values ​​back to the first recorded instantaneous value at this location are used. Here, too, in an advantageous further variant, the temperature limit value is also included in the calculation of the threshold value.

[0072] A further possible modification of the method is to determine the gradient limit or threshold value for each location based on the instantaneous values ​​at the location with the highest temperature and / or with the highest gradient. In order to optimally consider the influences in the environment of the housing of the electrochemical energy storage device, the ambient temperature of the respective location can be recorded at least before determining the threshold value. Subsequently, in a further variant, the algorithm implemented in the evaluation unit 9 can use this additional temperature value to adjust the threshold value depending on the ambient temperature. The method according to the invention for determining a first threshold value for the first temperature value of the first measuring field includes determining a first temperature value by the sensor 7 and the evaluation unit 9.Depending on the first temperature value recorded in the first measuring field at the beginning of a time interval, a threshold value is calculated for a second, subsequent temperature value, for which specific calculation rules and / or characteristic maps are specified in the evaluation unit 9. The beginning of the relevant time interval can be the time of activation of the device 1, but can also be later in time to allow for a complete start-up of all systems of the device and a stabilization of all measuring circuits and sensors.The calculation of the threshold value, which is used with the first temperature value to determine the gradient limit, can also include the history of all temperature values ​​determined in the time interval under consideration, preferably chronologically consecutively and beginning with the first time point of the time interval before the first threshold value, in order to obtain the threshold value for the next time point depending on the temperature dynamics of the first temperature values. According to a variant of the method, a warning message can also be issued by the device if the first threshold value is exceeded during the next temperature determination.

[0073] As a further variant with regard to the comparison of at least two groups of measuring fields or measuring points, a method is provided in which, by means of the sensor 7 or an arrangement of several such sensors, a simultaneous detection of at least one second temperature value from at least one second measuring field takes place at the first time and the subsequent times of the time interval. The second measuring field is positioned, controlled by the evaluation unit 9, such that it encompasses at least one region of the housing, and at least a partial measuring region of the second measuring field is arranged outside the first measuring field.Subsequently, the recorded second temperature values ​​of the time interval are stored in the storage unit, the recorded at least one first temperature value is compared with the at least one second temperature value at the same times by means of the evaluation unit, and here too the first threshold value is adjusted as a function of the second temperature values ​​at the respective time of the time interval.

[0074] Preferably, these threshold adjustments also take into account the environment of the housing of the electrochemical energy storage device, for example, the environment of a vehicle 2 with a drive battery 3. This allows for consideration of cooling influences, such as a wet or cold environment, as well as heating influences, such as a vehicle fire or a fire in the vicinity of the vehicle 2. For this purpose, an ambient temperature is automatically determined via the device 1, and the threshold is adjusted according to predeterminable or preprogrammed algorithms depending on the detected ambient temperature.

[0075] Preferably, at least the first measuring field is divided into clusters, wherein individual cluster areas of the cluster are advantageously provided with respect to individual zones (modules) of the electrochemical energy storage device. To ensure a high level of safety, the cluster area with the highest temperature values ​​is preferably used to determine and adjust the first threshold value and to compare the first temperature values. In a simplified manner and therefore with faster evaluation, a calculation can be carried out using a cluster segment, while only the rest of the cluster is monitored. If the relative temperature levels within the cluster change, the area of ​​the calculation and that of pure monitoring can also change, i.e. it is possible to jump from one cluster area to the other.

[0076] A second, chronologically subsequent threshold value with respect to the first temperature value is preferably determined via the evaluation unit 9 in such a way that a group of first temperature values ​​is compared with the second threshold value at several points in time and the temperature detection unit issues a warning message when the second threshold value is exceeded.

[0077] In order to be able to optimally adapt the monitoring to the respective application of the device 1, the positioning in relation to the housing or the vehicle 2 and other external conditions, various additional process variants are possible. For example, each measuring field or each point for temperature determination can be adjustable with regard to a length and a width of a detection area. Furthermore, position marking aids can be used as aids for the alignment of the device 1 or for sensors 7 whose alignment can be changed relative to the device 1. For example, a position marking could be projected onto the housing or a position marking, such as a grid, crosshairs or the like, is applied to a display of the temperature detection unit or is displayed there. The position marking advantageously comprises an outline of the at least one first measuring field.

[0078] Naturally, automatic self-monitoring mechanisms can be implemented in the device 1, particularly in the evaluation unit 9, to indicate faulty operating conditions. For example, the device 1 is configured to issue a notification if at least one of the following criteria is met: the first and second temperature values ​​of the first and second measuring fields are outside a tolerance with respect to the two temperature values ​​and / or the power supply of the device is insufficient for correct or complete detection of the required values ​​or insufficient for continued operation, or if the temperatures detected within a measuring field are outside a permissible tolerance.

[0079] An advantageous development of the method can offer an all-clear functionality to signal to emergency services or other users that the risk of escalation of the electrochemical energy storage device no longer exists by means of an all-clear signal that differs from the warning signals discussed so far. For this purpose, an algorithm implemented in the evaluation unit 9 of the device 1 checks whether the temperature threshold value has been reduced at several consecutive points in time or whether the gradient limit value has become correspondingly smaller and smaller. Advantageously, it can be specified after how many adjustments to lower temperature threshold values ​​or lower limit values ​​this all-clear signal is issued in order to cushion non-random fluctuations or changes in the ambient values.

[0080] The embodiments show possible embodiments, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments with each other are also possible and this possibility of variation lies within the skill of the person skilled in the art in this technical field due to the teaching of technical action by means of the objective invention.

[0081] For the sake of clarity, it should be noted that some elements have been shown not to scale and / or enlarged and / or reduced in size to improve understanding of the structure.

[0082] device

[0083] vehicle

[0084] battery

[0085] 3 a cell

[0086] Controls

[0087] Output unit

[0088] monitor

[0089] sensor

[0090] storage unit

[0091] Evaluation unit

[0092] Position

[0093] Area

[0094] Area

[0095] Vicinity

[0096] Thermal image

Claims

Patent claims 1. A method for the physically non-contact determination of a safety-critical state of at least one electrochemical energy storage device arranged in a housing, comprising the steps a) non-contact detection and storage of at least one instantaneous temperature value of at least one location on the outside of the housing, and comparison of the detected instantaneous value with a predetermined temperature limit for that location, wherein b) a warning signal is issued if the limit is exceeded, and c) if the instantaneous value is below the limit, a temperature gradient for that location is determined, wherein d) if the temperature gradient is greater than or equal to a gradient limit, a warning signal is also issued, and e) if the temperature gradient is less than the gradient limit, steps a) to e) are repeated.

2. Method according to claim 1, characterized in that f) instantaneous temperature values ​​are recorded at several locations on the outside of the housing, wherein a warning signal is issued when the temperature limit is exceeded at at least one location, and wherein g) if the instantaneous value is below the limit at all locations, the respective temperature gradient between the instantaneous values ​​recorded at the respective location is determined, h) if the temperature gradient is greater than or equal to a gradient limit at at least one location, a warning signal is issued, and i) if the temperature gradient is less than the gradient limit, steps f) to i) are repeated at all locations.

3. Method according to claim 2, characterized in that the instantaneous values ​​of a first group of locations are processed separately from the instantaneous values ​​of one or more further groups of other locations, which are at least largely spatially outside the first group.

4. Method according to claim 3, characterized in that the first group includes the location with the highest instantaneous value and / or with the largest temperature gradient, as well as those locations which are within a predetermined spatial distance and / or within a predetermined temperature difference to the location with the highest instantaneous value of the temperature and / or the largest temperature gradient.

5. Method according to one of claims 1 to 4, characterized in that the gradient limit value for at least the point with the highest value is adjusted before each new acquisition of an instantaneous value, depending on the course of the instantaneous values, preferably starting with the first recorded instantaneous value, and preferably also depending on the temperature limit value.

6. Method according to claim 5, characterized in that the gradient limit value is determined as a function of the last recorded instantaneous value and a threshold value for the next temperature value to be recorded, wherein the threshold value is determined as a function of the course of the instantaneous values, preferably back to the first recorded instantaneous value at this point, and preferably also as a function of the temperature limit value.

7. Method according to claim 6, characterized in that the gradient limit or threshold value for each location is determined on the basis of the instantaneous values ​​at the location with the highest temperature and / or with the highest gradient.

8. Method according to one of claims 6 or 7, characterized in that at least before the threshold value is determined, the ambient temperature of the respective location is recorded and the threshold value is adjusted depending on the ambient temperature.

9. Method according to one of the preceding claims, characterized in that the predetermined limit value and / or the gradient limit value is adapted depending on parameters that are characteristic of the respective monitored electrochemical energy storage device.

10. Method according to one of the preceding claims, characterized in that at least the detection at at least one location on the outside of the housing is supported by means of parameters for the electrochemical energy storage device that are characteristic of the respective monitored electrochemical energy storage device, taking into account a structural form and / or arrangement of the electrochemical energy storage device in the housing.

11. Portable device (1) for the physically contactless detection of a safety-critical state of at least one electrochemical energy storage device (3) arranged in a housing (2), comprising at least one housing, operating elements (4) and / or interfaces for user input, at least one output unit (5, 6) for at least one warning signal, and a) at least one sensor (7) for at least intermittently contactless detection of at least one instantaneous temperature value at at least one location on the outside of the housing, b) at least one storage unit (8) designed to store the instantaneous values, their timestamps, a predefinable temperature limit value, and a gradient limit value, c) at least one evaluation unit (9) designed to carry out the method according to at least one of claims 1 to 10.

12. Device according to claim 11, characterized in that at least one sensor (7) is formed by a thermal imaging camera.

13. Device according to claim 11 or 12, characterized in that an optical alignment aid is integrated.

14. Device according to one of claims 11 to 13, characterized in that manufacturer-specific parameters for electrochemical energy storage can be stored in the storage unit.

15. Device according to one of claims 11 to 14, characterized in that an orientation and / or position of the device with respect to the electrochemical energy storage in the storage unit can be stored.

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