Method and device for detecting thermal runaway of an electric battery of a motor vehicle

Abstract

The invention relates to a method for detecting thermal runaway of an electric battery (200) of a motor vehicle, at least comprising recording a pressure inside a battery housing (210) using at least one pressure sensor (10); recording an acceleration of the battery (200) using at least one acceleration sensor (20); processing pressure measured values (86) from the at least one pressure sensor (10) and acceleration measured values (88) from the at least one acceleration sensor (20) in a computing unit (30); setting a detection signal (90) for detecting the thermal runaway of the electric battery (200) on the basis of pressure measured values (86) from the at least one pressure sensor (10). In this case, at least one adapted pressure threshold value (83, 85) is used to set the detection signal (90), which adapted pressure threshold value is determined from at least one previous pressure threshold value (82, 84) on the basis of acceleration measured values (88) from the at least one acceleration sensor (20). The invention also relates to a device (100) for carrying out a method for detecting thermal runaway of an electric battery (200) of a motor vehicle.

Description

[0001] Method and device for detecting a thermal runaway of an electric battery of a motor vehicle

[0002] The invention relates to a method for detecting a thermal runaway of an electric battery of a motor vehicle and a device for carrying out a method for detecting a thermal runaway of an electric battery of a motor vehicle, with at least one battery control unit.

[0003] In a motor vehicle's electric battery, thermal runaway of the battery can be detected after the cell casing is opened during a thermal event, known as battery cell venting, via a pressure increase within the battery. The pressure increase generally occurs slowly, as a pressure equalization element is usually present in the battery casing.

[0004] DE 102014208627 A1 discloses a battery cell with a cell housing that defines a cell space for accommodating an electrochemical cell unit. The cell unit arranged in the cell housing is configured as a cell stack. A control unit is provided inside the cell stack, which has a detection unit for detecting state variables of the battery cell and a processing unit for processing the detected state variables.

[0005] DE 102021 000691 A1 discloses a device for monitoring an electric battery for a vehicle, which device comprises a pressure sensor for detecting a pressure within a battery housing and an acceleration sensor for sensing an acceleration of the battery. The pressure sensor and the acceleration sensor are designed as a common sensor component. The sensor component further comprises a pressure detection unit for detecting a pressure change and an evaluation unit, which is designed to determine from the detected pressure whether a thermal runaway of a battery cell is occurring, and to determine an acceleration of the battery from the pressure change and a collision severity from the acceleration of the battery. One object of the invention is to provide an improved method for detecting a thermal runaway of an electric battery of a motor vehicle.

[0006] A further object is to provide a device for carrying out a method for detecting a thermal runaway of an electric battery of a motor vehicle, with at least one battery control unit.

[0007] The above-mentioned objects are solved by the features of the independent claims.

[0008] Advantageous embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

[0009] According to one aspect of the invention, a method for detecting thermal runaway of an electric battery of a motor vehicle is proposed, at least comprising: detecting a pressure within a battery housing with at least one pressure sensor; detecting an acceleration of the battery with at least one acceleration sensor; processing pressure measurement values ​​of the at least one pressure sensor and acceleration measurement values ​​of the at least one acceleration sensor in a computing unit; setting a detection signal for detecting thermal runaway of the electric battery as a function of pressure measurement values ​​of the at least one pressure sensor. At least one adapted pressure threshold is used to set the detection signal, which is determined from at least one previous pressure threshold as a function of acceleration measurement values ​​of the at least one acceleration sensor.

[0010] The proposed method is designed to detect thermal runaway in a motor vehicle battery at an early stage. To detect thermal runaway, pressure measurements are used, which are compared with predefined pressure thresholds. Advantageously, these pressure thresholds are adjusted based on the battery's current acceleration values. This prevents false detections during pressure measurements.

[0011] The pressure sensor is combined with an acceleration sensor. This makes it possible to detect deformation of the battery casing due to acceleration or vibration, and to adjust the threshold for thermal runaway detection based on the pressure based on the acceleration values.

[0012] The pressure threshold represents a predefined reference value for detecting thermal runaway of the battery cells. The upper part of the battery casing, for example, can be a thin sheet of metal placed and glued over a relatively large, flat container, the lower part of the casing. If the battery is subjected to an impact or vibrations occur, this sheet of metal vibrates, compressing the gas volume in the battery casing. This increases the pressure in the battery casing without causing a battery cell to vent.

[0013] In order to avoid false triggering of the thermal runaway alarm due to pressure fluctuations caused, for example, by driving over a bollard and the resulting movement of the upper part of the battery housing, this pressure threshold can be increased depending on the measured acceleration, for example.

[0014] This advantageously results in a higher robustness of the detection and the pressure thresholds can be selected more narrowly, ie a thermal runaway of the battery can be detected earlier.

[0015] According to an advantageous embodiment of the method, the setting of the detection signal can be determined via pressure evaluation logic from the measured pressure value and at least one adjusted pressure threshold value. Pressure threshold values ​​can be both absolute pressure values ​​and threshold values ​​for a temporal change in the measured pressure value. Advantageously, the measured pressure values ​​can be compared with the pressure threshold values ​​adjusted using the acceleration values, and the occurrence of thermal runaway can be deduced from the comparison.

[0016] According to an advantageous embodiment of the method, the detection signal can be set when an absolute value of the measured pressure value exceeds an absolute value of the at least one adjusted pressure threshold. Alternatively or additionally, the detection signal can be set when an absolute value of a temporal pressure change value exceeds the absolute value of the at least one adjusted pressure threshold. Advantageously, absolute values ​​or differential values ​​of the measured pressure values ​​can be compared with the pressure thresholds adjusted using the acceleration measurements, and the occurrence of thermal runaway can be derived from the comparison.

[0017] According to an advantageous embodiment of the method, the adjusted pressure threshold can be determined using a function of the previous pressure threshold and the acceleration measurement. This function adapts the pressure threshold to the boundary conditions. Since the upper housing section may continue to vibrate slightly after an impact, this function can not only increase the threshold using a proportional factor, for example, but also implement a certain lag. This could be easily implemented by maintaining an increased threshold for a constant duration. It is also conceivable, however, that the pressure threshold increased due to the acceleration measurement is reduced over time to the previous value either linearly or in the form of an exponential function.

[0018] According to an advantageous embodiment of the method, the function can be implemented as a discrete function or as a continuous function. The pressure threshold can be adjusted discretely using a step function according to the measured acceleration values. Alternatively, the function can also increase the threshold using a proportional factor. It is also conceivable, however, that the pressure threshold, increased based on the measured acceleration values, changes linearly or exponentially over time and / or decreases back to the previous value.

[0019] According to an advantageous embodiment of the method, the adjusted pressure threshold can be set equal to the previous pressure threshold if the acceleration measurement falls below an acceleration threshold. If this is not the case, the adjusted pressure threshold can be set to a predetermined constant value. Thus, the pressure threshold can remain at its previous value if the acceleration experienced by the battery remains below an acceleration threshold. If a disturbance due to a temporary boundary condition, such as the excitation of battery vibrations due to uneven road surfaces, has been detected via the acceleration measurement, pressure detection can be practically deactivated for a short time by entering a very high or very low value.

[0020] According to an advantageous embodiment of the method, the adjusted pressure threshold can be determined via a linear relationship between the previous pressure threshold and the acceleration measurement. In particular, the adjusted pressure threshold can be determined as the sum of the previous pressure threshold and a product of a coefficient and the acceleration measurement. Thus, the pressure threshold increased based on the acceleration measurement can, for example, be changed linearly over time and / or reduced back to the previous value.

[0021] According to an advantageous embodiment of the method, the acceleration measurement value can be maintained at a previous maximum value over a predetermined time interval. This allows a certain apparent lag in the battery's acceleration to be specified.

[0022] Advantageously, acceleration can be recorded with a sampling rate of at least 1 kHz, while pressure can be recorded with a sampling rate of at least 100 Hz in an active measurement mode and at least 20 Hz in a rest mode. To reliably assess and identify the opening of the battery cell casing during a thermal event, known as venting of the battery cells, it is advantageous to record the pressure measurements in the active measurement mode with a sampling rate of at least 100 Hz. In a rest mode of the pressure sensor, however, a sampling rate of at least 20 Hz may be sufficient.

[0023] The processed measured values ​​from the pressure sensor and / or the acceleration sensor can advantageously be provided by the device's processing unit via the communication interface at a data rate of at least 10 Hz. This allows the battery control unit to initiate any fault reactions quickly enough in the event of a vehicle collision and / or thermal runaway of a battery cell.

[0024] According to an advantageous embodiment of the method, the processed measured values ​​of the pressure sensor and / or the acceleration sensor can be provided by the computing unit via the communication interface when at least one adapted pressure threshold and / or an acceleration threshold are exceeded. This allows the battery control unit to maintain a parking / rest mode with low power consumption in the normal state and yet initiate any fault reactions sufficiently quickly in the event of a vehicle collision and / or thermal runaway of a battery cell. Configuration parameters, in particular for processing measured values ​​of the pressure sensor and / or the acceleration sensor and / or threshold values, can advantageously be received by the computing unit via the communication interface.

[0025] According to a further aspect of the invention, a device for carrying out a method for detecting thermal runaway of an electric battery of a motor vehicle, with at least one battery control unit, is proposed, comprising at least one pressure sensor for detecting a pressure within a battery housing, at least one acceleration sensor for detecting an acceleration of the battery, a computing unit, and a communication interface. The computing unit is designed to process pressure measurement values ​​from the at least one pressure sensor and acceleration measurement values ​​from the at least one acceleration sensor, to set a detection signal for detecting thermal runaway of the electric battery, and to communicate with the at least one device-external battery control unit via the communication interface.

[0026] This advantageously allows for early detection of thermal runaway in a motor vehicle battery. To detect thermal runaway, pressure measurements are used, which are then compared with predefined pressure thresholds. Advantageously, the method adjusts these pressure thresholds based on the battery's current acceleration values. This prevents false detections during pressure measurements.

[0027] The pressure sensor is combined with an acceleration sensor. This makes it possible to detect deformation of the battery casing due to acceleration or vibration, and to adjust the threshold for thermal runaway detection based on the pressure based on the acceleration values.

[0028] The pressure threshold represents a predefined reference value for detecting thermal runaway of the battery cells. To prevent false triggering of the thermal runaway alarm due to pressure fluctuations, such as those caused by driving over a bollard and the resulting movement of the battery's upper housing, this pressure threshold can be increased depending on the measured acceleration, for example. This advantageously achieves greater robustness of the detection and allows for tighter pressure thresholds, meaning that thermal runaway of the battery can be detected earlier.

[0029] According to an advantageous embodiment of the device, the acceleration sensor can be designed to detect the acceleration of the battery in three orthogonal spatial directions. This ensures that realistic acceleration values ​​can be recorded.

[0030] Advantageously, the acceleration sensor can be designed to record acceleration values ​​with a sampling rate of at least 1 kHz.

[0031] The pressure sensor for detecting the pressure within the battery housing can advantageously be designed with a sampling rate of at least 100 Hz in an active measurement mode and at least 20 Hz in a sleep mode. To reliably assess and identify the opening of the battery cell housing during a thermal event, known as venting of the battery cells, it is advantageous to record the pressure measurements in the active measurement mode with a sampling rate of at least 100 Hz. In a sleep mode of the pressure sensor, however, a sampling rate of at least 20 Hz may be sufficient.

[0032] The computing unit for providing processed measurement data from the pressure sensor and / or the acceleration sensor via the communication interface can advantageously be designed with a data rate of at least 10 Hz. This allows the battery control unit to initiate any fault reactions quickly enough in the event of a vehicle collision and / or thermal runaway of a battery cell.

[0033] According to an advantageous embodiment of the device, the computing unit can comprise at least one function for determining at least one adapted pressure threshold value depending on acceleration measurement values ​​of the at least one acceleration sensor from a previous pressure threshold value and a pressure evaluation logic for setting the detection signal depending on pressure measurement values ​​of the pressure sensor.

[0034] The function can adapt the pressure threshold to the boundary conditions. Since the upper part of the housing may continue to vibrate slightly after an impact, this function can not only increase the threshold using a proportional factor, but also implement a certain amount of follow-up. This could be easily achieved by maintaining an elevated threshold for a constant duration. It is also conceivable, however, that the pressure threshold, which has been increased based on the acceleration measurements, could be reduced over time to its previous value either linearly or exponentially.

[0035] Pressure thresholds can be both absolute pressure values ​​and thresholds for a temporal change in the pressure measurement. This allows the pressure evaluation logic to compare the pressure measurements with the pressure thresholds adjusted using the acceleration measurements, and to determine whether a thermal runaway has occurred based on the comparison.

[0036] According to an advantageous embodiment of the device, the function can be configured to set the adjusted pressure threshold equal to the previous pressure threshold if the acceleration measurement value falls below an acceleration threshold, and, if this is not the case, to set the adjusted pressure threshold to a predetermined constant value. Alternatively or additionally, the function can be configured to determine the adjusted pressure threshold via a linear relationship between the previous pressure threshold and the acceleration measurement value. In particular, the function can be configured to determine the adjusted pressure threshold as the sum of the previous pressure threshold and a product of a coefficient and the acceleration measurement value.

[0037] For example, the pressure threshold can remain at its previous value if the acceleration experienced by the battery remains below an acceleration threshold. If a disturbance due to a temporary boundary condition, such as the excitation of battery vibrations caused by uneven road surfaces, has been detected based on the acceleration measurement, pressure detection can be virtually disabled for a short time by entering a very high or very low value. The pressure threshold, which has been increased based on the acceleration measurements, can, for example, be changed linearly over time and / or reduced back to the previous value.

[0038] According to an advantageous embodiment of the device, the pressure evaluation logic can be configured to set the detection signal when an absolute value of the measured pressure value exceeds an absolute value of the at least one adjusted pressure threshold value and / or when an absolute value of a temporal pressure change value exceeds the absolute value of the at least one adjusted pressure threshold value. Advantageously, absolute values ​​or differential values ​​of the measured pressure values ​​can be compared with the pressure threshold values ​​adjusted using the acceleration measured values, and the occurrence of thermal runaway can be derived from the comparison.

[0039] According to an advantageous embodiment of the device, the computing unit can be configured to provide processed measurement data from the pressure sensor and / or the acceleration sensor via the communication interface in an event-driven manner, particularly when at least one pressure threshold and / or one acceleration threshold is exceeded. This allows the battery control unit to maintain a parking / rest mode with low power consumption in the normal state and yet initiate any fault reactions sufficiently quickly in the event of a vehicle collision and / or thermal runaway of a battery cell.

[0040] Advantageously, the computing unit can be configured to receive configuration parameters, in particular for processing measurement data from the pressure sensor and / or the acceleration sensor and / or threshold values, via the communication interface. This enables the computing unit to appropriately control the pressure sensor and the acceleration sensor and, in particular, to process and evaluate the measurement data in a predeterminable manner. Configuration parameters can be sent to the device, for example, cyclically or upon request from the computing unit.

[0041] According to an advantageous embodiment, the device can further comprise a device housing, wherein the at least one pressure sensor, the at least one acceleration sensor, the computing unit, and the communication interface are arranged in the device housing. The device housing can be designed to be arranged on or in the battery. The device housing can be designed to be arranged on or in the battery. The device housing can, in particular, be rigidly connected to the battery housing in order to record representative accelerations for the battery. To detect pressure values ​​in the battery, the device housing can be arranged in the battery or at least be fluidly connected to the battery housing via an opening.

[0042] According to an advantageous embodiment of the device, the device housing can have a fluidic interface for detecting the pressure in the battery. In particular, the device housing can have an opening for fluidic connection to a battery housing of the battery. Advantageously, the pressure sensor can thus detect the pressure in the battery via the device housing arranged in the battery, which has an opening. With a device housing arranged on the battery housing, a suitable opening in both the battery housing and the device housing can establish the necessary fluidic connection between the pressure sensor and the interior of the battery.

[0043] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0044] Showing:

[0045] Fig. 1 is a system overview of a device for carrying out a method for detecting a thermal runaway of an electric battery of a motor vehicle, according to an embodiment of the invention;

[0046] Fig. 2 is a flowchart of a method for carrying out a method for detecting a thermal runaway of an electric battery of a motor vehicle according to an embodiment of the invention;

[0047] Fig. 3 is a flowchart of a method for carrying out a method for detecting a thermal runaway of an electric battery of a motor vehicle according to a further embodiment of the invention;

[0048] Fig. 4 is a flowchart of a method for executing a method for detecting a thermal runaway of an electric battery of a motor vehicle according to a further embodiment of the invention; and

[0049] Fig. 5 is a flowchart of a pressure evaluation logic of the method according to an embodiment of the invention.

[0050] In the figures, identical or similar components are designated by identical reference numerals. The figures merely show examples and are not to be understood as limiting. Figure 1 shows a system overview of a device 100 for executing a method for detecting thermal runaway of an electric battery 200 of a motor vehicle, according to an embodiment of the invention.

[0051] The device 100 comprises a pressure sensor 10 for detecting a pressure within a battery housing 210, an acceleration sensor 20 for detecting an acceleration of the battery 200, a computing unit 30, and a communication interface 40, which is electrically coupled to a battery control unit 50 via a CAN line 60 and a power supply 62. The power supply of the device 100 could also be provided via the battery 200.

[0052] The computing unit 30 is designed to process pressure measurement values ​​86 of the pressure sensor 10 and acceleration measurement values ​​88 of the acceleration sensor 20, to set a detection signal 90 for detecting the thermal runaway of the electric battery 200 and to communicate with the device-external battery control unit 50 by means of the communication interface 40.

[0053] The acceleration sensor 20 can advantageously be configured to detect the acceleration of the battery 200 in three orthogonal spatial directions and can detect acceleration values ​​at a sampling rate of at least 1 kHz. The pressure sensor 10 can, for example, be configured to detect the pressure within the battery housing at a sampling rate of at least 100 Hz in an active measurement mode and at least 20 Hz in a sleep mode. The computing unit 30 can advantageously be configured to provide processed measurement data from the pressure sensor 10 and / or the acceleration sensor 20 via the communication interface 40 at a data rate of at least 10 Hz.

[0054] The computing unit 30 can advantageously provide processed measurement data from the pressure sensor 10 and / or the acceleration sensor 20 via the communication interface 40 in an event-controlled manner, in particular when at least one pressure threshold 82, 84; 83, 85 and / or an acceleration threshold 89 is exceeded. Furthermore, the computing unit 30 is configured to receive configuration parameters, in particular for processing measurement data from the pressure sensor 10 and / or the acceleration sensor 20 and / or threshold values, via the communication interface 40 in order to suitably control the pressure sensor 10 and the acceleration sensor 20. The pressure sensor 10, acceleration sensor 20, computing unit 30, and communication interface 40 are arranged in a device housing. In the illustrated embodiment, the device housing is arranged in the battery 200. Alternatively, the device 100 could also be arranged externally on the battery housing 210.

[0055] The device housing 110 has a fluidic interface for detecting the pressure in the battery 200. This fluidic interface can, for example, be an opening for fluidic connection to the interior of the battery housing 210. Alternatively, a hose connection from the pressure sensor 10 to the interior of the battery housing 210 is also possible.

[0056] According to the proposed method, thermal runaway of the battery 200 can be detected by detecting a pressure within the battery housing 210 with the pressure sensor 10 and an acceleration of the battery 200 with the acceleration sensor 20. The pressure measurement values ​​86 of the pressure sensor 10 and the acceleration measurement values ​​88 of the acceleration sensor 20 are processed in the computing unit 30. A detection signal 90 for detecting thermal runaway of the battery 200 can then be set depending on the pressure measurement values ​​86 of the pressure sensor 10. At least one adjusted pressure threshold value 83, 85 is used to set the detection signal 90, which is determined from at least one previous pressure threshold value 82, 84 depending on the acceleration measurement values ​​88 of the acceleration sensor 20.

[0057] Figure 2 shows a flowchart of the method. Pressure measurement values ​​86, acceleration measurement values ​​88, and predefined positive and negative pressure threshold values ​​82, 84 are used to set the detection signal 90 for thermal runaway of the battery 200.

[0058] Pressure thresholds 82, 84 can be absolute pressure values ​​or relative pressure values, which are compared with absolute pressure measured values ​​or relative pressure measured values, respectively. Alternatively, the pressure thresholds 82, 84 can also be pressure change thresholds, which are compared with a temporal pressure change rate, i.e., a pressure gradient. The setting of the detection signal 90 itself is determined via a pressure evaluation logic 70 from the pressure measured value 86 and at least one adjusted positive and / or negative pressure threshold 83, 85.

[0059] The adjusted pressure threshold 83, 85 is in turn determined via a function 80 from the previous pressure threshold 82, 84 and the acceleration measurement value 88. The function 80 can be implemented as a discrete function or as a continuous function.

[0060] The adjusted pressure threshold 83, 85 can, for example, be set equal to the previous pressure threshold 82, 84 if the acceleration measurement value 88 falls below an acceleration threshold 89. If this is not the case, the adjusted pressure threshold 83, 85 can alternatively be set to a predefined constant value.

[0061] The adjusted new pressure threshold 83, 85 is set to a higher value, specifically a very high positive value in the case of a comparison with an absolute pressure. This value must be selected depending on the physical conditions. The example of a discrete threshold selection represents a simplified possibility: the threshold for the short period of the disturbance caused by acceleration is selected so high that pressure detection is de facto disabled. When considering the thresholds of the pressure gradients, a particularly negative value must be selected for the negative pressure gradient.

[0062] The detection signal 90 can be set, for example, when an absolute value of the pressure measurement value 86 exceeds an absolute value of the at least one adjusted pressure threshold value 83, 85 and / or when an absolute value of a temporal pressure change value 77, 78 exceeds the absolute value of the at least one adjusted pressure threshold value 83, 85, as explained in more detail in the embodiment in Figure 5.

[0063] The pressure evaluation logic 70 and the function 80 can advantageously be implemented in the form of a hardware module and / or a software module in the computing unit 30.

[0064] Figure 3 shows such an embodiment, in which the acceleration threshold 89 is fed as an additional input into the function 80. Furthermore, the adjusted pressure threshold 83, 85 can be determined via a linear relationship between the previous pressure threshold 82, 84 and the acceleration measurement 88. In particular, the adjusted pressure threshold 83, 85 can be determined as the sum of the previous pressure threshold 82, 84 and a product of a coefficient 81 and the acceleration measurement 88.

[0065] Such an embodiment is shown in Figure 4, in which the coefficient 81 is fed as an additional input into the function 80.

[0066] It may also be advantageous to keep the acceleration measurement value 88 at a previous maximum value over a predetermined time interval.

[0067] Figure 5 shows a flow chart of a pressure evaluation logic 70 of the method according to an embodiment of the invention.

[0068] The pressure evaluation logic 70 has two rate-of-change limiters 71, 72, both of which receive the measured pressure value 86 as input. The rate-of-change limiters 71, 72 limit the maximum rate of change of the measured pressure value 86. The outputs of the two rate-of-change limiters 71, 72, together with the original measured pressure value 86, are fed to two adders 73, 74, in which the difference between the rate-of-change-limited measured pressure value (input -) and the measured pressure value 86 (input +) itself is calculated. This difference is only non-zero if the rate of change is higher than the setting by the rate-of-change limiter 71, 72. The initial values ​​are positive and negative pressure change values ​​77, 78. This advantageously avoids a gradient calculation or differentiation of the pressure measurement value 86, which would lead to an amplification of the signal noise.

[0069] The positive and negative pressure change values ​​77, 78 (inputs in) are compared in two comparators 75, 76 with adjusted pressure thresholds 83, 85 (inputs th of comparators 75, 76). Comparator 75 is a greater-than comparator; in the path for undershooting a negative pressure gradient, comparator 76 is then a less-than comparator.

[0070] In this embodiment, the system does not react to exceeding an absolute pressure, but rather to a pressure gradient that is greater than the change rate limiter 71, 72 would allow. The pressure threshold 83, 85 in this case is a pressure change threshold.

[0071] The comparison with a negative pressure gradient is important because after the battery cells have been vented, i.e. when the pressure increases sharply, an equally strong, or even more strong, pressure drop can occur due to the opening of a bursting membrane on the battery.

[0072] Outputs of the comparators 75, 76 represent detection signals 92, 94 for a positive or negative pressure change, respectively. The two detection signals 92, 94 can then be further combined within the pressure evaluation logic 70 to form a detection signal 90 for thermal runaway.

[0073] List of reference symbols

[0074] 10 Pressure sensor

[0075] 20 Accelerometer

[0076] 30 computing units

[0077] 40 Communication interface

[0078] 50 Battery control unit

[0079] 60 CAN cable

[0080] 62 Power supply

[0081] 70 Pressure evaluation logic

[0082] 71 Rate of change limiter

[0083] 72 Rate of Change Limiters

[0084] 73 adders

[0085] 74 adders

[0086] 75 comparators

[0087] 76 comparators

[0088] 77 pos. pressure change value

[0089] 78 negative pressure change value

[0090] 80 Function

[0091] 81 Coefficient

[0092] 82 pos. pressure threshold

[0093] 83 adjusted positive pressure threshold

[0094] 84 negative pressure threshold

[0095] 85 adjusted negative pressure threshold

[0096] 86 pressure measurement value

[0097] 88 Acceleration measurement value

[0098] 89 Acceleration threshold

[0099] 90 Thermal runaway detection signal

[0100] 92 Detection signal positive pressure change

[0101] 94 Detection signal negative pressure change

[0102] 100 device

[0103] 110 fixture housing

[0104] 200 battery

[0105] 210 Battery housing

Claims

Method for detecting a thermal runaway of an electric battery (200) of a motor vehicle, comprising at least Detecting a pressure within a battery housing (210) with at least one pressure sensor (10); Detecting an acceleration of the battery (200) with at least one acceleration sensor (20); Processing pressure measurement values ​​(86) of the at least one pressure sensor (10) and acceleration measurement values ​​(88) of the at least one acceleration sensor (20) in a computing unit (30); Setting a detection signal (90) for detecting thermal runaway of the electric battery (200) as a function of pressure measurement values ​​(86) from the at least one pressure sensor (10), wherein at least one adjusted pressure threshold value (83, 85) is used to set the detection signal (90), which is determined as a function of acceleration measurement values ​​(88) from the at least one acceleration sensor (20) from at least one previous pressure threshold value (82, 84). The method according to claim 1, wherein the setting of the detection signal (90) is determined via pressure evaluation logic (70) from the pressure measurement value (86) and at least one adjusted pressure threshold value (83, 85). The method according to claim 1 or 2, wherein the detection signal (90) is set when an absolute value of the pressure measurement value (86) exceeds an absolute value of the at least one adjusted pressure threshold value (83, 85) and / or when an absolute value of a temporal pressure change value (77, 78) exceeds the absolute value of the at least one adjusted pressure threshold value (83, 85). The method according to one of the preceding claims, wherein the adjusted pressure threshold value (83, 85) is determined via a function (80) from the previous pressure threshold value (82, 84) and the acceleration measurement value (88). The method according to claim 4, wherein the function (80) is implemented as a discrete function or as a continuous function.Method according to one of the preceding claims, wherein the adjusted pressure threshold (83, 85) is set equal to the previous pressure threshold (82, 84) if the acceleration measurement value (88) falls below an acceleration threshold (89), and wherein, if this is not the case, the adjusted pressure threshold (83, 85) is set to a predetermined constant value. Method according to one of the preceding claims, wherein the adjusted pressure threshold (83, 85) is determined via a linear relationship between the previous pressure threshold (82, 84) and the acceleration measurement value (88), in particular wherein the adjusted pressure threshold (83, 85) is determined as the sum of the previous pressure threshold (82, 84) and a product of a coefficient (81) and the acceleration measurement value (88).Method according to one of the preceding claims, wherein the acceleration measurement value (88) is maintained at a previous maximum value over a predetermined time interval. Method according to one of the preceding claims, wherein the processed measured values ​​of the pressure sensor (10) and / or the acceleration sensor (20) are provided by the computing unit (30) via the communication interface (40) when at least one adjusted pressure threshold value (83, 85) and / or an acceleration threshold value (89) is exceeded. Device (100) for carrying out a method for detecting a thermal runaway of an electric battery (200) of a motor vehicle according to one of the preceding claims, comprising at least one battery control unit (50), comprising - at least one pressure sensor (10) for detecting a pressure within a battery housing (210), - at least one acceleration sensor (20) for detecting an acceleration of the battery (200), a computing unit (30), a communication interface (40), wherein the computing unit (30) is designed to process pressure measurement values ​​(86) of the at least one pressure sensor (10) and acceleration measurement values ​​(88) of the at least one acceleration sensor (20), to set a detection signal (90) for detecting thermal runaway of the electric battery (200), and to communicate with the at least one device-external battery control unit (50) by means of the communication interface (40). Device according to claim 10, wherein the acceleration sensor (20) is designed to detect the acceleration of the battery (200) in three orthogonal spatial directions.Device according to claim 10 or 11, wherein the computing unit (30) comprises at least one function (80) for determining at least one adapted pressure threshold value (83, 85) as a function of acceleration measurement values ​​(88) of the at least one acceleration sensor (20) from a previous pressure threshold value (82, 84) and a pressure evaluation logic (70) for setting the detection signal (90) as a function of pressure measurement values ​​(86) of the pressure sensor (10). Device according to claim 12, wherein the function (80) is designed to set the adjusted pressure threshold value (83, 85) equal to the previous pressure threshold value (82, 84) if the acceleration measurement value (88) falls below an acceleration threshold value (89), and, if this is not the case, to set the adjusted pressure threshold value (83, 85) to a predetermined constant value and / or wherein the function (80) is designed to determine the adjusted pressure threshold value (83, 85) via a linear relationship between the previous pressure threshold value (82, 84) and the acceleration measurement value (88), in particular to determine the adjusted pressure threshold value (83, 85) as the sum of the previous pressure threshold value (82, 84) and a product of a coefficient (81) and the acceleration measurement value (88).The device according to claim 12 or 13, wherein the pressure evaluation logic (70) is configured to set the detection signal (90) when an absolute value of the pressure measurement value (86) exceeds an absolute value of the at least one adjusted pressure threshold value (83, 85) and / or when an absolute value of a temporal pressure change value (77, 78) exceeds the absolute value of the at least one adjusted pressure threshold value (83, 85). The device according to one of claims 10 to 14, wherein the computing unit (30) is configured to provide processed measurement data of the pressure sensor (10) and / or the acceleration sensor (20) via the communication interface (40) in an event-controlled manner, in particular when at least one pressure threshold value (82, 84; 83, 85) and / or an acceleration threshold value (89) is exceeded.Device according to one of claims 10 to 15, further comprising a device housing (110), wherein the at least one pressure sensor (10), the at least one acceleration sensor (20), the computing unit (30), the communication interface (40) are arranged in the device housing, wherein the device housing is designed to be arranged on or in the battery (200). Device according to one of claims 10 to 16, wherein the device housing (110) has a fluidic interface for detecting the pressure in the battery (200), in particular wherein the device housing has an opening for fluidic connection to a battery housing (210) of the battery (200).

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