Method, computer program product, and electronic computing device for determining thermal runaway in the electrical energy storage unit of an at least partially electrically driven automobile.

Abstract

The present invention relates to a method for determining thermal runaway of an electric energy store (12) of a driven motor vehicle, the method comprising: - a continuous monitoring of the electrical energy store (12) by means of at least one diagnostic means (14) of the electrical energy store (12) on the basis of a diagnostic signal (16), - if an anomaly (44) is detected in the diagnostic signal (16), determining the frequency (18) of the anomaly (44); - if an anomaly (44) is detected in the diagnostic signal (16), determining the magnitude of the anomaly (44); - continuously monitoring the communication line (24) by means of a limited anomaly counter (26); - if an anomaly (44) is detected in the communication line (24), performing a comparison between the limited anomaly counter (26) and the non-limited anomaly counter (28) and generating a difference signal (30) in response to the comparison; - determining thermal runaway as a function of the determined frequency (18), the determined momentum (22) and the difference signal (30). The invention further relates to a computer program product as well as an electronic computing device (10).

Description

Technical Field

[0001] The present invention relates to a method for determining thermal runaway of an electrical energy storage unit of a motor vehicle that is at least partially electrically driven, using an electronic computing device of the motor vehicle as described in the superordinate concept of claim 1. The present invention further relates to a computer program product and an electronic computing device.

Background Art

[0002] For example, in a so-called battery for an electric vehicle, which is an electrical energy storage unit of a motor vehicle, there is a risk that thermal runaway, also referred to as Thermal Runaway, may occur. For example, it is already known that a warning must be issued to the occupants of the motor vehicle 5 minutes before a fire occurs. At present, in vehicles, a combination of voltage measurement and insulation measurement is used. When both undervoltage and poor insulation are detected, an alarm is triggered. However, errors are relatively likely to occur in the measurement of poor insulation. Further, it is also known to incorporate a dedicated additional sensor such as a pressure sensor. However, this increases the cost. Furthermore, the cell temperature itself can be used. However, not all battery cells have sensors, and furthermore, depending on the mounting position, they may be well shielded from the hot gas, so there may also be a significant time lag in the temperature sensor. Measuring only the cell voltage is unreliable because false warnings are likely to occur frequently. For example, when the measurement line is cut, this may cause a false warning due to the lack of a further signal for validity checking and the resulting appearance of undervoltage. Patent Document 1 relates to an apparatus for identifying thermal runaway, a battery system, and a method for identifying thermal runaway in a battery system. The apparatus for identifying thermal runaway includes a first measuring module for measuring the temperature values ​​of multiple cells via at least one temperature sensor, a second measuring module for measuring the output voltage value of the battery system, and a control unit for identifying thermal runaway in the battery system by monitoring data received from the first measuring module, determining the effectiveness of identifying thermal runaway based on the temperature value, and selectively monitoring the temperature value or the output voltage value according to the result of the determination of the effectiveness of identifying thermal runaway based on the temperature value. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] EP3843195A1 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The object of the present invention is to provide a method, a computer program product, and an electronic computing device that can more effectively detect thermal runaway in an electrical energy storage unit. [Means for solving the problem]

[0005] This problem is solved by the method described in the independent claim, a computer program product, and an electronic computing device. Advantageous embodiments are described in the dependent claims.

[0006] One aspect of the present invention relates to a method for determining thermal runaway in an electrical energy storage unit of an automobile that is at least partially electrically driven, using the automobile's electronic computer. This method involves continuous monitoring of the electrical energy storage unit using at least one diagnostic means for determining the current state of the electrical energy storage unit based on a diagnostic signal. If an abnormality is detected in the diagnostic signal, the frequency of abnormalities in the diagnostic signal over a predetermined period is determined. Furthermore, if an abnormality is detected in the diagnostic signal, the frequency of abnormalities in the diagnostic signal over a predetermined period is determined. movement The determination is made. The communication line of the electrical energy storage unit is continuously monitored using a limited anomaly counter. If an anomaly is detected in the communication line, a comparison is made between the limited anomaly counter and the non-limited anomaly counter, and a difference signal is generated according to the comparison. The determined frequency, the determined movement Furthermore, a thermal runaway detection is performed based on the difference signal.

[0007] This improves the ability to identify thermal runaway within the electrical energy storage unit.

[0008] Therefore, thermal runaway in battery cells or electrical energy storage units, particularly in the form of lithium-ion batteries, can be robustly detected without the need for additional sensor systems. Since the cell monitoring electronic device is a component of an electrical energy storage unit, especially an electric vehicle battery, appropriate diagnostics are already performed to achieve so-called ASIL safety. Consequently, component costs are not incurred, and software expansion is similarly minimal. Therefore, thermal runaway can already be identified at a reduced cost by using existing systems or methods.

[0009] Therefore, in particular, in order to determine thermal runaway, cell voltage measurement is used, diagnostics for cell voltage measurement are performed, signals derived from the diagnostics are calculated, thresholds are formed, and the diagnostics are combined via appropriate AND operations.

[0010] Therefore, in particular, cell monitoring electronic devices have the task of measuring cell voltage and cell temperature. Since these values ​​are used to achieve safety objectives according to the ASIL classification, they are checked by diagnostics for proper functioning. These diagnostics are triggered when such errors / anomalies exist. Many of these errors occur, and in part, simultaneously, during thermal runaway, also known as thermal runaway. The challenge here is to isolate thermal runaway from the actual error cases. Even worse, many hardware errors trigger multiple diagnostics, especially when thermal runaway does not occur. Here, in order to achieve better discrimination, on the one hand, errors or anomalies movement One factor is taken into consideration, while the other factor is the number of errors or anomalies that occur simultaneously.

[0011] Furthermore, during thermal runaway, accumulated communication errors also occur in transmissions via so-called daisy-chains, which correspond to communication lines and can be formed as, for example, a CAN bus. In implementations using so-called ASICs for analog functional components, these errors are counted using a so-called packet error counter (PEC). This PEC is equivalent to an unrestricted error counter. However, even under normal conditions, for example, when a protector switches, multiple packets may be degraded, so inspection is also performed here. For this purpose, the PEC uses a so-called rate limiter, or in other words, a restricted error counter, to... movement This is then restricted, and subsequently, the difference between this and the actual PEC corresponding to the unrestricted anomaly counter is identified. If this difference signal exceeds a threshold, this suggests thermal runaway.

[0012] Therefore, abnormal movement Based on the number of anomalies occurring simultaneously and the combination of differential signals, thermal runaway can be estimated without any particularly erroneous detection.

[0013] According to an advantageous embodiment, a diagnostic means is used to monitor the interruption of the cell voltage circuit. In particular, this diagnostic means is a diagnostic means already incorporated into a vehicle for monitoring the cell voltage measurement circuit. This diagnostic means can check whether or not an abnormality exists, and also detect the abnormality. movement Furthermore, the frequency can be monitored. This method is, in particular, the so-called open-wire method.

[0014] Furthermore, it has been found that this diagnostic means is advantageous when the switching state of a balancing semiconductor element is monitored. The balancing semiconductor element is, in particular, a so-called balancing FET element. Specifically, it can be used to check, for example, whether this semiconductor element is not switched on or is in a continuously switched-on state. This diagnostic means is similar to the diagnostic means already incorporated into automobiles to monitor electrical energy storage units.

[0015] In another advantageous embodiment, this diagnostic means is used to monitor for short circuits between adjacent pins on a circuit board of an electronic computing device. Similarly, this diagnostic means is a method already incorporated into automobiles for monitoring electrical energy storage units or electronic computing devices. In particular, this involves monitoring whether a short circuit has occurred between adjacent general-purpose input / output (GPIO) pins. That is, for example, pins in an ASIC to which a temperature sensor is connected are monitored.

[0016] Furthermore, this diagnostic means can be used to monitor deviations in the second reference voltage source. This diagnostic means is also a method already incorporated into automobiles to monitor electrical components, particularly battery cells, thereby enabling the detection of thermal runaway in a simple manner.

[0017] Furthermore, it was found that this diagnostic method is advantageous when the total voltage is monitored via the circuit board of an electronic computing device. Specifically, the total voltage is monitored via an ASIC, and in particular, whether this total voltage is equal to the sum of the individual voltages is monitored. This method is also already incorporated into automobiles or electrical energy storage units, so it can estimate thermal runaway in a reliable and simple way.

[0018] In another advantageous embodiment, a difference signal is generated only when a predetermined threshold is exceeded between a limited anomaly counter and an unlimited anomaly counter. For example, the limited anomaly counter can limit its rate to four errors per second. If the threshold exceeds, for example, 20, this can be considered to indicate the presence of errors / anomalies.

[0019] In an advantageous embodiment, when potential thermal runaway is detected, the vehicle's output device outputs a warning message to the occupants inside the vehicle. In particular, this warning message is output at least 5 minutes before thermal runaway occurs. The output device may be a tactile, optical, or acoustic output device. In particular, various warning messages, such as an acoustic warning signal, an optical warning signal, and a tactile warning signal, may be output simultaneously.

[0020] The method presented is a method implemented in a computer. Therefore, another aspect of the present invention relates to a computer program product in which, when the program code means is processed by a computer, the program code means causes a computer to carry out the method according to the aforementioned aspect. In particular, the above method is carried out using a computer. The computer program product may also be called a computer program.

[0021] Therefore, another aspect of the present invention also relates to computer-readable storage media, including computer program products.

[0022] Furthermore, the present invention also relates to an electronic computing device for determining a thermal runaway of an electrical energy storage unit of a motor vehicle that is at least partially electrically driven, the electronic computing device being formed to carry out the method according to the above-described aspects. In particular, the above method is carried out using this electronic computing device.

[0023] The electronic computing device has, for example, a processor, a circuit, in particular an integrated circuit, and other electronic components in order to be able to carry out the corresponding method steps.

[0024] Similarly, the present invention also relates to a motor vehicle that is at least partially electrically driven or fully electrically driven.

[0025] Advantageous embodiments of the method are considered to be advantageous embodiments of a computer program product, an electronic computing device, and a motor vehicle. The electronic computing device and the motor vehicle have, in particular, features that enable the implementation of the corresponding method steps.

[0026] Further advantages, features, and details of the present invention will become apparent from the following description of preferred embodiments and the drawings. The features, combinations of features, as mentioned in the above description, and the features and / or combinations of features mentioned in the description of a plurality of drawings and / or shown in a single drawing below are not only the combinations described, but can also be used in other combinations or alone without departing from the scope of the present invention.

Brief Description of the Drawings

[0027] [Figure 1] Here, the only figure shows a schematic block diagram according to an embodiment of the method.

Embodiments for Carrying Out the Invention

[0028] In the drawings, the same or functionally identical elements are provided with the same reference signs.

[0029] This figure shows a schematic block diagram of one embodiment of an electronic computing device 10 for determining thermal runaway of an electrical energy storage unit 12 of an at least partially electrically driven automobile. In this embodiment, the operation process is particularly shown. In particular, continuous monitoring of the electrical energy storage unit 12 is performed using at least one diagnostic means 14 for determining the current state of the electrical energy storage unit 12 based on a diagnostic signal 16. If an abnormality 44 is detected in the diagnostic signal 16, the frequency 18 of the abnormality 44 in the diagnostic signal 16 over a predetermined period 20 is determined. Furthermore, if an abnormality 44 is detected in the diagnostic signal 16, the frequency 18 of the abnormality 44 in the diagnostic signal 16 over a predetermined period 20 movement 22 is determined. Furthermore, the communication line 24 of the electrical energy storage unit 12 is continuously monitored using the limited anomaly counter 26. If an anomaly 44 is detected in the communication line 24, the limited anomaly counter 26 and the non-limited anomaly counter 28 are compared, and a difference signal 30 is generated according to the comparison. Here again, the determined frequency 18 and the determined movement A thermal runaway detection is performed based on 22 and the difference signal 30.

[0030] In particular, threshold comparisons can be performed for this purpose. For example, a first threshold 32 greater than 100 can be set as a measure of frequency 18. In other words, a warning signal 34 for thermal runaway can be issued only when 100 or more anomalies 44 are identified. Furthermore, a second threshold 36 can be set, and this second threshold is here movement It represents, movementThis may relate to the absolute value of the derivative of the set number of bits, and may include, for example, a second threshold 36 of 10 or more. A third threshold 38 may be provided, which here represents a measure of significantly frequent communication errors, and this may be, for example, greater than 20. Only when the comparison of all three thresholds is classified positively, that is, only when thresholds 32 and 36 are exceeded, are they introduced into the AND operation 40. If all three thresholds 32, 36 and 38 are exceeded, a warning message 34 is generated. The warning message 34 may be output, for example, in an output device 42 of an automobile. For example, the output device 42 may be formed as a display device, a speaker device, or a tactile device.

[0031] Period 20 could be, for example, 20 seconds, or it could be a different time span, for example, 40 seconds.

[0032] As already mentioned, it is shown here that an AND operation 40 is performed. For example, instead of performing threshold formation before the AND operation 40, an alternative form is conceivable in which a weighted addition is performed, and then threshold formation is performed only afterward.

[0033] Accordingly, the drawings specifically show that the cell monitoring electronic device has the task of measuring cell voltage and cell temperature. Since these values ​​are used to achieve safety objectives according to the corresponding ASIL classification, correct function is monitored using diagnostic means 14. Such diagnostics include, for example, the interruption of the cell voltage measurement circuit, so-called open wire diagnostics. Furthermore, diagnostic means 14 can also be used to monitor, for example, a balancing semiconductor switching element. For example, it can be checked whether this semiconductor element is not switched on or is continuously switched on. This is also referred to as a balancing FET stack. Furthermore, short circuits between adjacent boards, so-called general-purpose input / output (GPIO) can also be checked. In particular, in the ASIC, it is checked whether a short circuit has occurred at the corresponding pin to which, for example, a temperature sensor is connected. Furthermore, deviations of a second reference voltage source can also be used for monitoring. Furthermore, the total voltage can also be checked via the ASIC, for example, whether this total voltage is equal to the sum of the individual voltages.

[0034] The diagnostic means 14 described above is triggered when that type of error / anomaly 44 exists. During thermal runaway, many of these errors occur, and some occur simultaneously. The challenge here is to isolate thermal runaway from the actual error cases. Even worse, many hardware errors trigger multiple diagnostic means 14 even when thermal runaway is not present. Herein, in order to achieve better discrimination, the anomaly 44 movement Both frequency 22 and frequency 18 are considered.

[0035] Furthermore, during thermal runaway, accumulated communication errors also occur during transmission via communication lines 24, particularly so-called daisy-chains. In implementations using ASICs for analog devices, these errors are counted using a so-called non-limited error counter 28 (packet error counter (PEC)). However, even under normal conditions, for example, during contactor switching, multiple packets may be degraded, so discrimination is also performed here. For this purpose, the PEC uses a limited error counter 26, a so-called rate-limiter, movement This is then restricted, and the difference with the actual PEC is determined. If this difference signal 30 exceeds a threshold, in this case the third threshold, this suggests thermal runaway.

[0036] The limited anomaly counter 26 can limit the rate to, for example, four errors or anomalies 44 per second.

[0037] Frequency 18, movement 22. Furthermore, if the difference signal 30 exceeds the corresponding thresholds 32, 36, and 38, thermal runaway is recognized based on the AND operation 40, and a warning signal 34 is generated. [Explanation of Symbols]

[0038] 10 Electronic computing device 12 Electrical energy storage unit 14. Diagnostic methods 16 Diagnostic signals 18 Frequency 20 period twenty two movement 24 Communication lines 26 Limited Abnormal Counter 28 Non-limited abnormal counter 30 Difference signal 32 First threshold 34 Warning Messages 36. Second threshold 38. The third threshold 40 AND operation 42 Output device 44 Abnormal

Claims

1. A method for determining thermal runaway of an electrical energy storage unit (12) of an automobile that is at least partially electrically driven, using an electronic computer (10) of the automobile, - A step of continuously monitoring the electrical energy storage unit (12) using at least one diagnostic means (14) for determining the current state of the electrical energy storage unit (12) based on a diagnostic signal (16), - If an abnormality (44) is detected in the diagnostic signal (16), the step of determining the frequency (18) of the abnormality (44) in the diagnostic signal (16) over a predetermined period (20), - If an abnormality (44) is detected in the diagnostic signal (16), the step of determining the movement (22) of the abnormality (44) in the diagnostic signal (16) over a predetermined period (20), - A step of continuously monitoring the communication line (24) of the electrical energy storage unit (12) using a limited abnormality counter (26) that counts communication errors only under normal conditions, - When an abnormality (44) is detected in the communication line (24), the limited abnormality counter (26) is compared with the non-limited abnormality counter (28), which counts communication errors without being limited to the normal state, and a difference signal (30) is generated according to the comparison, - A step of determining the thermal runaway (44) according to the determined frequency (18), the determined movement (22), and the difference signal (30), A method of having.

2. The method according to claim 1, characterized in that the interruption of the cell voltage measurement circuit is monitored using the diagnostic means (14).

3. The method according to claim 1 or 2, characterized in that the switching state of the balancing semiconductor element is monitored using the diagnostic means (14).

4. The method according to claim 1 or 2, characterized in that a short circuit between adjacent pins on the circuit board of the electronic computing device (10) is monitored using the diagnostic means (14).

5. The method according to claim 1 or 2, characterized in that the deviation of the second reference voltage source is monitored using the diagnostic means (14).

6. The method according to claim 1 or 2, characterized in that the total voltage is monitored via the circuit board of the electronic computing device (10) using the diagnostic means (14).

7. The method according to claim 1 or 2, characterized in that the difference signal (30) is generated only when a predetermined threshold is exceeded between the limited abnormality counter (26) and the non-limited abnormality counter (38).

8. The method according to claim 1 or 2, characterized in that when potential thermal runaway is detected, the output device (42) of the vehicle outputs a warning message (34) to the occupants inside the vehicle.

9. A computer program product including program code means, The computer program product wherein, when the program code means is processed by a computer (10), the program code means causes the computer (10) to carry out the method described in claim 1 or 2.

10. An electronic computing device (10) for determining thermal runaway of an electrical energy storage unit (12) of an electric vehicle that is at least partially electrically driven, The electronic computer (10) is configured to carry out the method described in claim 1 or 2.

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