Thermal runaway detection method and device

Abstract

The invention discloses a thermal runaway detection method and device, and the method comprises the steps: obtaining cell data, and obtaining a first detection result based on the cell data and a preset first parameter threshold group; acquiring pressure data in the battery pack, and acquiring a second detection result based on the pressure data in the battery pack and a preset second parameter threshold group; and performing fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result. According to the method, the BMS and the multi-source data are combined, the cell data and the pressure data in the battery pack are comprehensively considered, even if the BMS breaks down, the pressure data of the VCU still detect effective information of the pressure in the battery pack, the problem of detection failure caused by a single fault point is avoided, and the detection error-tolerant rate is increased. Through cross validation of multi-source data, whether the battery is in a thermal runaway state can be more accurately judged, and the possibility of misjudgment and missed judgment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle detection and control, and particularly to a thermal runaway detection method and device. Background Art

[0002] In recent years, new energy vehicles have developed rapidly, and pure electric vehicles and plug-in hybrid electric vehicles have gradually become the main technical routes of new energy vehicles. At the same time, the public's attention to the safety of power batteries has also been continuously improved. Therefore, reliable judgment and timely alarm of thermal runaway are the key research technologies at present.

[0003] In the existing thermal runaway detection method, the battery management system (BMS) is used to detect battery data to determine whether the vehicle has a thermal runaway, and the vehicle is controlled according to the vehicle control unit (VCU) for thermal runaway control. However, only by detecting through the BMS, when the BMS fails, the vehicle cannot determine whether there is a thermal runaway, and the fault tolerance rate of thermal runaway detection is low and the reliability is not high. Summary of the Invention

[0004] The present invention provides a thermal runaway detection method and device to improve the reliability of thermal runaway detection.

[0005] To solve the above technical problems, an embodiment of the present invention provides a thermal runaway detection method, including:

[0006] Obtaining cell data, and obtaining a first detection result based on the cell data and a preset first parameter threshold group;

[0007] Obtaining the pressure data inside the battery pack, and obtaining a second detection result based on the pressure data inside the battery pack and a preset second parameter threshold group;

[0008] Performing fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result.

[0009] The present invention combines multi-source data of the BMS and the VCU to detect cell data and battery voltage data, thereby setting up a dual-path detection. Based on the cell data obtained from the BMS and a preset first parameter threshold, it is determined whether there is an abnormality in the cell; based on the pressure data inside the battery pack obtained from the VCU and a preset second parameter threshold, it is determined whether there is a pressure abnormality in the battery. The first detection result and the second detection result are fused and judged, comprehensively considering the cell data and the pressure data inside the battery pack. Even if the BMS fails, the vehicle VCU can still detect the effective information of the pressure inside the battery pack, avoiding the problem of detection failure caused by a single fault point and improving the detection fault tolerance rate. Through the cross-validation of multi-source data, it is possible to more accurately determine whether the battery is in a thermal runaway state, reducing the possibility of misjudgment and missed judgment.

[0010] Further, the obtaining of the cell data and the obtaining of the first detection result based on the cell data and a preset first parameter threshold group include:

[0011] Obtain cell data based on the BMS system, where the cell data includes cell temperature data and cell voltage data;

[0012] Based on the cell temperature data, obtain the maximum temperature, the maximum temperature difference, and the temperature change rate, and based on the cell voltage, obtain the voltage drop and the minimum voltage;

[0013] The first parameter threshold group includes a temperature threshold group and a voltage threshold group; based on the maximum temperature, the maximum temperature difference, the temperature change rate, and the temperature threshold group, judge the abnormal temperature state of the battery; based on the minimum voltage, the voltage drop, and the voltage threshold group, obtain the abnormal voltage state of the battery;

[0014] Based on the abnormal temperature state and the abnormal voltage state, obtain the first detection result.

[0015] The present invention evaluates the battery state by obtaining the temperature and voltage data of the cell through the BMS system. The maximum temperature and the maximum temperature difference reflect the highest temperature and the local temperature difference inside the battery, while the temperature change rate indicates the rising speed of the battery temperature. Using the maximum temperature, the maximum temperature difference, the temperature change rate, the voltage drop, and the minimum voltage as signals of thermal runaway occurrence, and using a preset temperature threshold group and voltage threshold group as reference criteria for judging the battery state, based on the result of parameter comparison, the abnormal temperature state and the abnormal voltage state of the battery can be obtained. Finally, based on the abnormal temperature state and the abnormal voltage state, the first detection result is obtained.

[0016] Further, the abnormal voltage state includes a first voltage state and a second voltage state; the voltage threshold group includes a first voltage threshold and a second voltage threshold; the obtaining of the abnormal voltage state of the battery based on the minimum voltage, the voltage drop, and the voltage threshold group includes:

[0017] If the minimum voltage is less than or equal to the first voltage threshold, and the duration for which the minimum voltage is less than or equal to the first voltage threshold exceeds a preset first time threshold, then the abnormal voltage state is the first voltage state;

[0018] If within a preset second time threshold, the voltage drop is greater than or equal to the second voltage threshold, then the abnormal voltage state is the second voltage state.

[0019] The present invention identifies the abnormal voltage state of the battery by detecting the minimum voltage and the voltage drop of the battery in detail, and combining the preset first voltage threshold, second voltage threshold, and corresponding time thresholds; the minimum voltage reflects the current lowest voltage point of the battery, which may be the abnormal voltage of a certain battery cell inside the battery or the manifestation of the overall voltage drop of the battery. Too low voltage may mean problems such as over-discharge or internal short circuit of the battery. The voltage drop refers to the drop amplitude of the battery voltage within a certain period of time. Too fast voltage drop may indicate abnormal discharge behavior or short circuit inside the battery. By comparing the relationship between the minimum voltage and the first voltage threshold and combining the judgment of the duration, it is identified whether the battery is in a severely low voltage state. By comparing the relationship between the voltage drop and the second voltage threshold, the voltage drop speed of the battery within a certain period of time is judged. By subdividing the voltage abnormal state into two levels and combining the time threshold for judgment, the abnormal voltage behavior of the battery can be identified more precisely.

[0020] Further, the abnormal temperature state includes a first temperature state, a second temperature state, a third temperature state, and a fourth temperature state; the temperature threshold group includes a first temperature threshold, a second temperature threshold, and a temperature change threshold; the judgment of the abnormal temperature state of the battery based on the maximum temperature, the maximum temperature difference, the temperature change rate, and the temperature threshold group includes:

[0021] If the maximum temperature is greater than or equal to the first temperature threshold, and the duration for which the maximum temperature is greater than or equal to the first temperature threshold exceeds a preset third time threshold, then the abnormal temperature state is the first temperature state;

[0022] If the temperature change rate is greater than or equal to the temperature change threshold, and the duration for which the temperature change rate is greater than or equal to the temperature change threshold exceeds a preset third time threshold, then the abnormal temperature state is the second temperature state;

[0023] If the temperature detection device is in an open - circuit state and the duration of the open - circuit state of the temperature detection device exceeds a preset fourth time threshold, then the abnormal temperature state is the third temperature state;

[0024] If the maximum temperature difference is greater than or equal to the second temperature threshold and the duration of the maximum temperature difference being greater than or equal to the second temperature threshold exceeds a preset third time threshold, then the abnormal temperature state is the fourth temperature state.

[0025] By comprehensively evaluating the maximum temperature, the maximum temperature difference, the temperature change rate, and the state of the temperature detection device, the method of the present invention can more comprehensively monitor the thermal state of the battery and timely detect potential thermal runaway risks.

[0026] Further, obtaining the first detection result based on the abnormal temperature state and the abnormal voltage state includes:

[0027] If the battery is in the first voltage state and there is the first temperature state, then the first detection result is that the battery has a thermal runaway;

[0028] If the battery is in the first voltage state and there is the second temperature state, then the first detection result is that the battery has a thermal runaway;

[0029] If the battery is in the first voltage state and there is the third temperature state, then the first detection result is that the battery has a thermal runaway;

[0030] If the battery is in the second voltage state and there is the first temperature state, then the first detection result is that the battery has a thermal runaway;

[0031] If the battery is in the second voltage state and there is the second temperature state, then the first detection result is that the battery has a thermal runaway;

[0032] If the battery is in the second voltage state and there is the fourth temperature state, then the first detection result is that the battery has a thermal runaway.

[0033] The present invention combines and judges the abnormal voltage state (the first voltage state, the second voltage state) and the abnormal temperature state (the first temperature state, the second temperature state, the third temperature state, the fourth temperature state). Through multiple - condition combination, it can cover various abnormal situations that may lead to thermal runaway, ensuring the comprehensiveness and accuracy of the detection result.

[0034] Further, obtaining the pressure data inside the battery pack includes:

[0035] Obtaining the pressure data inside the battery pack based on the VCU system; the pressure data includes the current pressure and the pressure change data.

[0036] The present invention obtains the pressure data of the battery through the VCU system. The pressure data can reflect the chemical and physical changes inside the battery; the current pressure represents the real-time pressure value inside the battery. It is judged whether the battery is within the normal operating pressure range through the current pressure. If the pressure is too high, it may mean that there are abnormal conditions inside the battery; the pressure change data reflects the change trend and speed of the pressure inside the battery. If the pressure changes rapidly or abnormally, it may indicate potential safety problems.

[0037] Further, obtaining the second detection result based on the pressure data in the battery pack and a preset second parameter threshold group includes:

[0038] The second parameter threshold group includes a pressure threshold and a pressure change threshold;

[0039] When the current pressure is greater than the pressure threshold, the second detection result is that the battery has a thermal runaway;

[0040] When the pressure change rate is greater than the pressure change threshold, the second detection result is that the battery has a thermal runaway.

[0041] The present invention sets a preset pressure threshold and a pressure change threshold, and judges whether the pressure inside the battery is too high through the pressure threshold. If the current pressure exceeds this threshold, it indicates that abnormal conditions may have occurred inside the battery; judges whether the pressure change inside the battery is too fast through the pressure change threshold. If the pressure change rate exceeds this threshold, it indicates that a violent chemical reaction may be occurring inside the battery. Thus, the second detection result is generated. By combining the dual judgments of the absolute value of the pressure and the pressure change trend, it can effectively avoid misjudgment of a single parameter and improve the reliability of the detection result.

[0042] Further, performing a fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result includes:

[0043] If both the BMS system and the VCU system are operating normally, then when both the first detection result and the second detection result are that the battery has a thermal runaway, the thermal runaway detection result is that the battery has a thermal runaway.

[0044] The present invention obtains the final thermal runaway detection result by fusing the first detection result and the second detection result when both the battery management system (BMS) and the vehicle control unit (VCU) are operating normally. By combining the two independent detection results, the possibility of false alarms can be reduced. Because only when both independent detection systems confirm that the battery has a thermal runaway, a thermal runaway alarm is issued, which can avoid false alarms caused by single system failures or misjudgments.

[0045] Further, the method of fusing and determining based on the first detection result and the second detection result to obtain a thermal runaway detection result includes:

[0046] When the BMS system is in a failure state, if the second detection result indicates that the battery has a thermal runaway, the thermal runaway detection result is that the battery has a thermal runaway.

[0047] In the present invention, when the BMS system fails, it may not be able to normally obtain and process key data such as the voltage and temperature of the battery. Therefore, the first detection result (based on voltage and temperature status) may not provide effective information. In this case, the second detection result (based on pressure data and pressure change data) of the VCU system is relied on to determine whether the vehicle has a thermal runaway. When the second detection result is "the battery has a thermal runaway", even if the BMS system fails, the final thermal runaway detection result is still "the battery has a thermal runaway".

[0048] In a second aspect, the present invention provides a thermal runaway detection device, including: a first detection module, a second detection module, and a determination module;

[0049] The first detection module is configured to obtain cell data and obtain a first detection result based on the cell data and a preset first parameter threshold group;

[0050] The second detection module is configured to obtain pressure data inside the battery pack and obtain a second detection result based on the pressure data inside the battery pack and a preset second parameter threshold group;

[0051] The determination module is configured to perform a fusion determination based on the first detection result and the second detection result to obtain a thermal runaway detection result. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a schematic flowchart of a thermal runaway detection method provided by an embodiment of the present invention;

[0053] Figure 2 is a schematic diagram of cell data acquisition provided by the present invention;

[0054] Figure 3 is a schematic diagram of voltage data acquisition provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0056] In the description, claims, and drawings of this application, terms such as "first" and "second" are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally further include steps or units not listed, or may optionally further include other steps or units inherent to these processes, methods, products, or devices.

[0057] Reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of this application. The phrase appears at various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0058] Embodiment 1

[0059] Refer to Figure 1 , Figure 1 is a schematic flowchart of a thermal runaway detection method provided by an embodiment of the present invention. An embodiment of the present invention provides a thermal runaway detection method, including steps 101 to 103, specifically as follows:

[0060] Step 101: Obtain cell data, and obtain a first detection result based on the cell data and a preset first parameter threshold group;

[0061] In this embodiment, the obtaining of the cell data and obtaining the first detection result based on the cell data and the preset first parameter threshold group includes:

[0062] Obtain cell data based on the BMS system, where the cell data includes cell temperature data and cell voltage data;

[0063] Obtain the maximum temperature, the maximum temperature difference, and the temperature change rate based on the cell temperature data, and obtain the voltage drop and the minimum voltage based on the cell voltage;

[0064] The first parameter threshold group includes a temperature threshold group and a voltage threshold group; judge the abnormal temperature state of the battery based on the maximum temperature, the maximum temperature difference, the temperature change rate, and the temperature threshold group; obtain the abnormal voltage state of the battery based on the minimum voltage, the voltage drop, and the voltage threshold group;

[0065] Obtain a first detection result based on the abnormal temperature state and the abnormal voltage state.

[0066] Please refer toFigure 2 , Figure 2 A schematic diagram of battery cell data acquisition provided by the present invention.

[0067] In this embodiment, each series-connected battery cell unit in the power battery system is equipped with a voltage detection module, which is detected and processed by the BMS, so as to realize the detection of the real-time voltage and voltage change of each series-connected battery cell unit. The temperature and voltage of the battery cell are obtained through the BMS system, so as to realize the detection of the real-time voltage and voltage change of each series-connected battery cell unit.

[0068] In this embodiment, a voltage sampling circuit is set for each series-connected battery cell unit in the battery system. This voltage sampling circuit can be implemented in various ways, such as wire harness sampling, FPC flexible printed circuit loop, or PCB printed circuit board, which can detect the change of the battery cell voltage in real time and transmit it to the BMS, so as to collect the battery cell voltage data through the BMS.

[0069] In this embodiment, the voltage of each battery cell is continuously monitored through the voltage sampling circuit to evaluate its state of charge (SOC) and state of health (SOH), and the battery cell voltage data is transmitted to the BMS, so as to transmit the battery cell voltage data to the vehicle controller (VDC) through the BMS, so as to judge whether the vehicle will have a thermal runaway.

[0070] In this embodiment, temperature acquisition sensors are provided for some battery cells in the battery system (the installation positions of the temperature sensors must be able to detect the highest and lowest temperatures in the battery system), which can collect the temperature and temperature change in the battery system in real time and transmit them to the BMS.

[0071] In this embodiment, the BMS collects the battery temperature data, so as to obtain the maximum temperature, the maximum temperature difference and the temperature change rate through the battery temperature data. The maximum temperature and the maximum temperature difference reflect the highest temperature and the local temperature difference inside the battery, while the temperature change rate indicates the rising speed of the battery temperature.

[0072] In this embodiment, the maximum temperature, the maximum temperature difference, the temperature change rate, the voltage drop and the minimum voltage are used as signals for the occurrence of thermal runaway, and the preset temperature threshold group and voltage threshold group are used as reference standards for judging the battery state. Based on the result of parameter comparison, the abnormal temperature state and abnormal voltage state of the battery can be obtained. Finally, the first detection result is obtained based on the abnormal temperature state and abnormal voltage state.

[0073] In this embodiment, the abnormal voltage state includes a first voltage state and a second voltage state; the voltage threshold group includes a first voltage threshold and a second voltage threshold; the obtaining of the abnormal voltage state of the battery based on the minimum voltage, the voltage drop and the voltage threshold group includes:

[0074] If the minimum voltage is less than or equal to the first voltage threshold, and the duration for which the minimum voltage is less than or equal to the first voltage threshold exceeds a preset first time threshold, then the abnormal voltage state is the first voltage state;

[0075] If within a preset second time threshold, the voltage drop is greater than or equal to the second voltage threshold, then the abnormal voltage state is the second voltage state.

[0076] In this embodiment, by detecting in detail the minimum battery voltage and the voltage drop, and combining with the preset first voltage threshold, second voltage threshold, and corresponding time thresholds, the abnormal voltage state of the battery is identified; the minimum voltage reflects the current lowest voltage point of the battery, which may be due to the abnormal voltage of a certain cell inside the battery or the overall voltage drop of the battery. Too low voltage may mean problems such as over-discharge or internal short circuit of the battery. The voltage drop refers to the drop in the battery voltage within a certain period of time. A too fast voltage drop may indicate abnormal discharge behavior or short circuit inside the battery. By comparing the relationship between the minimum voltage and the first voltage threshold, and combining with the judgment of the duration, it is identified whether the battery is in a severely low voltage state. By comparing the relationship between the voltage drop and the second voltage threshold, the voltage drop speed of the battery within a certain period of time is judged.

[0077] In this embodiment, the first voltage threshold is usually used to define the lower limit of the normal operating voltage range of the battery. When the battery voltage drops below this threshold, it may indicate that the battery is about to run out or there is an abnormality. The first voltage threshold is set based on the battery specifications and the battery operating voltage.

[0078] In this embodiment, the actual operating voltage of the battery may be affected by factors such as load and temperature. Therefore, when setting the first voltage threshold, these factors need to be considered to ensure that the threshold is neither too sensitive nor too insensitive.

[0079] In this embodiment, the first voltage threshold is set to 1.6V.

[0080] In this embodiment, the second voltage threshold is used to define the lower limit of the safety protection voltage range of the battery. When the voltage drop value of the battery within a short period of time reaches the second voltage threshold, it indicates that the battery has a serious fault or is about to be in danger.

[0081] In this embodiment, the second voltage threshold is 1.6V.

[0082] In this embodiment, the first voltage threshold and the second voltage threshold should be set according to the specific battery type and specifications, and fine-tuned based on the actual working scenario.

[0083] In this embodiment, the duration is judged by the first time threshold, avoiding the possibility of misjudgment due to a single low voltage. Only when the state where the minimum voltage is less than or equal to the first voltage threshold lasts for more than a certain time (the first time threshold), is it considered a true abnormal voltage state.

[0084] In this embodiment, the first time threshold is set to 1.5 seconds.

[0085] In this embodiment, the time window is judged by the second time threshold to ensure that the detection of the voltage drop has practical significance. Only when the voltage drop exceeds the preset threshold within a short time (the second time threshold), is it considered a signal of abnormal voltage state.

[0086] In this embodiment, the second time threshold is set to 5 seconds.

[0087] In this embodiment, if the minimum voltage is less than or equal to 1.6V and the duration exceeds 1.5 seconds, the battery is in the first voltage state.

[0088] In this embodiment, if the voltage drop is greater than or equal to 1.6V within the preset 5 seconds, the battery is in the second voltage state.

[0089] In this embodiment, the first voltage state corresponds to a situation where the battery voltage is severely too low, which may be caused by over-discharging of the battery, internal short circuit or other serious faults, and is a high-risk signal of thermal runaway; the second voltage state corresponds to a situation where the battery voltage drops rapidly, which may be caused by internal short circuit or abnormal discharge of the battery, and is also a potential cause of thermal runaway.

[0090] In this embodiment, by subdividing the voltage abnormal state into two levels and combining the time threshold for judgment, the abnormal voltage behavior of the battery can be identified more precisely, avoiding misjudgment of a single voltage parameter (such as the minimum voltage or the voltage drop), and at the same time providing more reliable data support for subsequent thermal runaway detection.

[0091] In this embodiment, the abnormal temperature state includes a first temperature state, a second temperature state, a third temperature state and a fourth temperature state; the temperature threshold group includes a first temperature threshold, a second temperature threshold and a temperature change threshold; the judging of the abnormal temperature state of the battery based on the maximum temperature, the maximum temperature difference, the temperature change rate and the temperature threshold group includes:

[0092] If the maximum temperature is greater than or equal to the first temperature threshold and the duration for which the maximum temperature is greater than or equal to the first temperature threshold exceeds the preset third time threshold, the abnormal temperature state is the first temperature state;

[0093] If the rate of temperature change is greater than or equal to the temperature change threshold, and the duration for which the rate of temperature change is greater than or equal to the temperature change threshold exceeds a preset third time threshold, then the abnormal temperature state is the second temperature state;

[0094] If the temperature detection device is in an open circuit state, and the duration for which the temperature detection device is in an open circuit state exceeds a preset fourth time threshold, then the abnormal temperature state is the third temperature state;

[0095] If the maximum temperature difference is greater than or equal to the second temperature threshold, and the duration for which the maximum temperature difference is greater than or equal to the second temperature threshold exceeds a preset third time threshold, then the abnormal temperature state is the fourth temperature state.

[0096] In this embodiment, by comprehensively evaluating the maximum temperature, the maximum temperature difference, the rate of temperature change, and the state of the temperature detection device, this method can more comprehensively monitor the thermal state of the battery and timely detect potential thermal runaway risks.

[0097] In this embodiment, the first temperature threshold, the second temperature threshold, and the temperature change threshold are set through a thermal runaway experiment.

[0098] In this embodiment, the first temperature threshold is used to specify the highest temperature of the battery cell. When the highest temperature exceeds the first temperature threshold, it indicates that the battery may undergo thermal runaway.

[0099] In this embodiment, the first temperature threshold is set to 67°C.

[0100] In this embodiment, the second temperature threshold is used to specify the maximum temperature difference of the battery cell. When the temperature difference of the cell is higher than the second temperature threshold, it indicates that the battery may undergo thermal runaway.

[0101] In this embodiment, the second temperature threshold is set to 28°C.

[0102] In this embodiment, the temperature change threshold is used to specify the rate of temperature change of the battery cell. When the rate of temperature change exceeds the temperature change threshold, it indicates that the battery may undergo thermal runaway.

[0103] In this embodiment, the temperature change threshold is set to 2°C / 0.6S.

[0104] In this embodiment, the third time threshold is the time length for detecting the battery temperature. When the time for which the battery temperature is in an abnormal state exceeds this third time threshold, it can be determined that the battery may undergo thermal runaway.

[0105] In this embodiment, the third time threshold is set to 2 seconds.

[0106] In this embodiment, the fourth time threshold is used for the time length of circuit anomaly monitoring of the temperature detection device of the battery. Only when the time of the temperature detection device in the abnormal state exceeds this fourth time threshold can it be determined that the battery may have a thermal runaway.

[0107] In this embodiment, the fourth time threshold is set to 20 seconds.

[0108] As a specific example of the embodiment of the present invention, based on the "Safety Requirements for Power Batteries for Electric Vehicles GB38031", a thermal runaway test at the battery pack level is carried out. After detecting the actual occurrence of thermal runaway, it is checked whether the highest temperature of the battery cell triggers the assumed threshold 1. If the assumed threshold 1 is triggered, this assumed threshold 1 is set as the first temperature threshold; if the assumed threshold 1 is not triggered, after adjusting to the assumed threshold 2 according to the detected actual value, the thermal runaway experiment is carried out again until the assumed threshold n is successfully triggered.

[0109] In this embodiment, if the maximum temperature is greater than or equal to 67 °C and the duration exceeds 2S, then the abnormal temperature state is the first temperature state; the first temperature state indicates that the battery temperature is too high and the duration is long, which is a direct signal of thermal runaway.

[0110] In this embodiment, if the temperature change rate is greater than or equal to 2 °C / 0.6S and the duration exceeds 2S, then the abnormal temperature state is the second temperature state. The second temperature state indicates that the battery temperature change rate is too fast, which may indicate a sharp rise in the battery temperature and is an early signal of thermal runaway.

[0111] In this embodiment, if the temperature detection device is in an open circuit state and the duration exceeds 20S, then the abnormal temperature state is the third temperature state; the third temperature state: indicates that the temperature detection device fails, which may lead to inaccurate temperature monitoring and there is a risk of thermal runaway.

[0112] In this embodiment, if the maximum temperature difference is greater than or equal to 28 °C and the duration exceeds the preset 2S, then the abnormal temperature state is the fourth temperature state. The fourth temperature state indicates that the temperature difference inside the battery is too large, which may be caused by local overheating and is a potential signal of thermal runaway.

[0113] In this embodiment, by comprehensively evaluating the maximum temperature, the maximum temperature difference, the temperature change rate, and the state of the temperature detection device, this method can more comprehensively monitor the thermal state of the battery and timely detect potential thermal runaway risks.

[0114] In this embodiment, obtaining the first detection result based on the abnormal temperature state and the abnormal voltage state includes:

[0115] If the battery is in the first voltage state and there is the first temperature state, the first detection result is that the battery has thermal runaway;

[0116] If the battery is in the first voltage state and there is the second temperature state, the first detection result is that the battery has thermal runaway;

[0117] If the battery is in the first voltage state and there is the third temperature state, the first detection result is that the battery has thermal runaway;

[0118] If the battery is in the second voltage state and there is the first temperature state, the first detection result is that the battery has thermal runaway;

[0119] If the battery is in the second voltage state and there is the second temperature state, the first detection result is that the battery has thermal runaway;

[0120] If the battery is in the second voltage state and there is the fourth temperature state, the first detection result is that the battery has thermal runaway.

[0121] In this embodiment, the abnormal voltage states (the first voltage state, the second voltage state) and the abnormal temperature states (the first temperature state, the second temperature state, the third temperature state, the fourth temperature state) are combined for judgment. Through multiple condition combinations, various abnormal conditions that may cause thermal runaway can be covered, ensuring the comprehensiveness and accuracy of the detection results.

[0122] In this embodiment, if the battery is in the first voltage state and there is the first temperature state, that is, the minimum voltage is less than or equal to the first voltage threshold, and the duration for which the minimum voltage is less than or equal to the first voltage threshold exceeds the preset first time threshold, and at the same time, the maximum cell temperature is greater than or equal to the first temperature threshold, and the duration for which the maximum temperature is greater than or equal to the first temperature threshold exceeds the preset third time threshold, then the first detection result is that the battery has thermal runaway;

[0123] As a specific example of the embodiment of the present invention, the minimum voltage is less than or equal to 1.6V, and the duration exceeds 1.5S, and at the same time, the maximum cell temperature is greater than or equal to 67°C, and the duration exceeds 2S, then the first detection result is that the battery has thermal runaway;

[0124] In this embodiment, if the battery is in the first voltage state and there is the second temperature state, that is, the minimum voltage is less than or equal to the first voltage threshold, and the duration for which the minimum voltage is less than or equal to the first voltage threshold exceeds the preset first time threshold, and at the same time, the temperature change rate is greater than or equal to the temperature change threshold, and the duration for which the temperature change rate is greater than or equal to the temperature change threshold exceeds the preset third time threshold, then the first detection result is that the battery has thermal runaway;

[0125] As a specific example of an embodiment of the present invention, if the minimum voltage is less than or equal to 1.6V and the duration exceeds 1.5S, and at the same time, the temperature change rate of the battery cell is greater than or equal to 2°C / 0.6S and the duration exceeds 2S, then the first detection result is that the battery has a thermal runaway;

[0126] In this embodiment, if the battery is in the first voltage state and there is a third temperature state, that is, the minimum voltage is less than or equal to the first voltage threshold, and the duration of the minimum voltage being less than or equal to the first voltage threshold exceeds the preset first time threshold, and at the same time, the duration of the temperature detection device being in an open circuit state exceeds the preset fourth time threshold, then the first detection result is that the battery has a thermal runaway;

[0127] As a specific example of an embodiment of the present invention, if the minimum voltage is less than or equal to 1.6V and the duration exceeds 1.5S, and at the same time, the temperature detection device of the battery is in an open circuit state, and the duration of the temperature detection device being in an open circuit state exceeds 20S, then the first detection result is that the battery has a thermal runaway;

[0128] In this embodiment, if the battery is in the second voltage state and there is a first temperature state, that is, within the preset second time threshold, the voltage drop is greater than or equal to the second voltage threshold, and at the same time, the duration of the maximum temperature of the battery cell being greater than or equal to the first temperature threshold exceeds the preset third time threshold, then the first detection result is that the battery has a thermal runaway;

[0129] As a specific example of an embodiment of the present invention, if within 5S, the voltage drop is greater than or equal to 1.6V, and at the same time, the maximum temperature of the battery cell is greater than or equal to 67°C and the duration exceeds 2S, then the first detection result is that the battery has a thermal runaway, then the first detection result is that the battery has a thermal runaway;

[0130] In this embodiment, if the battery is in the second voltage state and there is a second temperature state, that is, within the preset second time threshold, the voltage drop is greater than or equal to the second voltage threshold, and at the same time, the temperature change rate is greater than or equal to the temperature change threshold, and the duration of the temperature change rate being greater than or equal to the temperature change threshold exceeds the preset third time threshold, then the first detection result is that the battery has a thermal runaway;

[0131] As a specific example of an embodiment of the present invention, if within 5S, the voltage drop is greater than or equal to 1.6V, and at the same time, the temperature change rate of the battery cell is greater than or equal to 2°C / 0.6S and the duration exceeds 2S, then the first detection result is that the battery has a thermal runaway, then the first detection result is that the battery has a thermal runaway;

[0132] In this embodiment, if the battery is in the second voltage state and there is a fourth temperature state, that is, within a preset second time threshold, the voltage drop is greater than or equal to the second voltage threshold. At the same time, the maximum temperature difference is greater than or equal to the second temperature threshold, and the duration for which the maximum temperature difference is greater than or equal to the second temperature threshold exceeds a preset third time threshold, then the first detection result is that the battery has experienced thermal runaway.

[0133] As a specific example of the embodiment of the present invention, if within 5S, the voltage drop is greater than or equal to 1.6V, and at the same time, the maximum temperature difference is greater than or equal to 28°C, and the duration exceeds 2S, then the first detection result is that the battery has experienced thermal runaway.

[0134] In this embodiment, the combination of the voltage state and the temperature state can reflect a serious abnormal condition of the battery. For example, the battery voltage being too low (the first voltage state) and the temperature being too high (the first temperature state) means that the battery may already be at the critical point of thermal runaway. The combination of an overly rapid temperature change rate (the second temperature state) or an overly large temperature difference (the fourth temperature state) and voltage anomalies further strengthens the risk judgment of thermal runaway. Through the combined judgment of the voltage and temperature states, various abnormal conditions that may lead to thermal runaway can be covered, ensuring the comprehensiveness of the detection. The multiple conditional combinations of the temperature state and the voltage state can detect abnormal conditions in the early stage when the battery experiences thermal runaway. At the same time, through multi-parameter detection, the possibility of misjudgment by a single parameter is avoided, improving the reliability of the detection result.

[0135] Step 102: Obtain the pressure data inside the battery pack, and obtain a second detection result based on the pressure data inside the battery pack and a preset second parameter threshold group;

[0136] Please refer to Figure 3 , Figure 3 which is a schematic diagram of voltage data acquisition provided by the present invention.

[0137] In this embodiment, the obtaining of the pressure data inside the battery pack includes:

[0138] Obtain the pressure data inside the battery pack based on the VCU system; the pressure data includes the current pressure and the pressure change data.

[0139] In this embodiment, the exhaust passage inside the power battery system is equipped with a pressure sensor, which can monitor the pressure and pressure changes inside the battery system in real time, and this signal is collected and processed by the vehicle VCU.

[0140] In this embodiment, by continuously monitoring the pressure data of the battery, potential safety hazards can be detected in a timely manner. For example, if the internal pressure of the battery suddenly increases, it may mean that the battery is experiencing thermal runaway or other abnormal conditions, and immediate measures need to be taken to prevent accidents.

[0141] In this embodiment, the pressure data of the battery is obtained through the VCU system. The pressure data can reflect the chemical and physical changes inside the battery; the current pressure represents the real-time pressure value inside the battery. It is judged whether the battery is within the normal operating pressure range through the current pressure. If the pressure is too high, it may mean that there are abnormal conditions inside the battery; the pressure change data reflects the change trend and speed of the internal pressure of the battery. If the pressure changes rapidly or abnormally, it may indicate potential safety problems.

[0142] In this embodiment, obtaining the second detection result based on the pressure data inside the battery pack and a preset second parameter threshold group includes:

[0143] The second parameter threshold group includes a pressure threshold and a pressure change threshold;

[0144] When the current pressure is greater than the pressure threshold, the second detection result is that the battery has thermal runaway;

[0145] When the pressure change rate is greater than the pressure change threshold, the second detection result is that the battery has thermal runaway.

[0146] In this embodiment, by presetting the pressure threshold and the pressure change threshold, it is judged whether the internal pressure of the battery is too high through the pressure threshold. If the current pressure exceeds this threshold, it indicates that abnormal conditions may have occurred inside the battery; it is judged whether the internal pressure change of the battery is too fast through the pressure change threshold. If the pressure change rate exceeds this threshold, it indicates that a violent chemical reaction may be occurring inside the battery. Thus, the second detection result is generated. Combining the dual judgments of the absolute value of the pressure and the pressure change trend can effectively avoid misjudgment of a single parameter and improve the reliability of the detection result.

[0147] Step 103: Perform a fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result.

[0148] In this embodiment, performing a fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result includes:

[0149] If both the BMS system and the VCU system are operating normally, then when both the first detection result and the second detection result are that the battery has thermal runaway, the thermal runaway detection result is that the battery has thermal runaway.

[0150] In this embodiment, when both the battery management system (BMS) and the vehicle control unit (VCU) are operating normally, the final thermal runaway detection result is obtained by fusing the first detection result and the second detection result. By combining the two independent detection results, the possibility of false alarms can be reduced. Because only when both independent detection systems confirm that the battery has experienced thermal runaway, an alarm for thermal runaway is issued, thus avoiding false alarms caused by single system failures or misjudgments.

[0151] In this embodiment, on the premise that both the BMS and the VCU are operating normally, the data of the two systems are mutually verified, improving the reliability of the entire thermal runaway detection system. If one of the systems fails or has abnormal data, it may not trigger an alarm for thermal runaway, thereby preventing safety accidents caused by single-point failures and improving the reliability of thermal runaway judgment.

[0152] In this embodiment, the fusion judgment based on the first detection result and the second detection result to obtain the thermal runaway detection result includes:

[0153] If the BMS system is in a failure state, then when the second detection result indicates that the battery has experienced thermal runaway, the thermal runaway detection result is that the battery has experienced thermal runaway.

[0154] In this embodiment, when the BMS system fails, it may not be able to normally obtain and process key data such as the voltage and temperature of the battery. Therefore, the first detection result (based on voltage and temperature status) may not provide effective information. In this case, rely on the second detection result (based on pressure data and pressure change data) of the VCU system to determine whether the vehicle has experienced thermal runaway. When the second detection result is "the battery has experienced thermal runaway", even if the BMS system fails, the final thermal runaway detection result is still "the battery has experienced thermal runaway".

[0155] In this embodiment, if the VCU fails, the BMS can independently judge thermal runaway through the battery voltage signal and temperature signal, and obtain the first detection result, thereby judging whether the vehicle has experienced thermal runaway according to the first detection result.

[0156] The embodiment of the present invention also provides a thermal runaway detection device, including: a first detection module, a second detection module, and a judgment module;

[0157] The first detection module is used to obtain cell data and obtain a first detection result based on the cell data and a preset first parameter threshold group;

[0158] The second detection module is used to obtain the pressure data inside the battery pack and obtain a second detection result based on the pressure data inside the battery pack and a preset second parameter threshold group;

[0159] The judgment module is configured to perform a fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result.

[0160] In an embodiment of the present invention, a terminal device is further provided, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the above-mentioned thermal runaway detection method is implemented.

[0161] In an embodiment of the present invention, a computer-readable storage medium is further provided. The computer-readable storage medium includes a stored computer program. When the computer program runs, it controls the device where the computer-readable storage medium is located to execute the above-mentioned thermal runaway detection method.

[0162] Exemplarily, the computer program may be divided into one or more modules. One or more modules are stored in the memory and executed by the processor to complete the present invention. One or more modules may be a series of computer program instruction segments capable of performing specific functions, and these instruction segments are used to describe the execution process of the computer program in the terminal device.

[0163] The terminal device may be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor, a memory, and a display. Those skilled in the art can understand that the above components are only examples of the terminal device and do not constitute a limitation on the terminal device. It may include more or fewer components than those described, or combine some components, or different components. For example, the terminal device may further include input / output devices, network access devices, a bus, etc.

[0164] The so-called processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The processor is the control center of the terminal device and connects various parts of the entire terminal device through various interfaces and lines.

[0165] The memory can be used to store computer programs and / or modules. By running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory, the processor can implement various functions of the terminal device. The memory mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, a text conversion function, etc.); the data storage area can store data created according to the use of the mobile phone (such as audio data, text message data, etc.). In addition, the memory can include high-speed random access memory, and can also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0166] Among them, if the module based on the thermal runaway detection is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the above-mentioned embodiment methods of the present invention, it can also be completed by instructing relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, an executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disc, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. Those of ordinary skill in the art can understand and implement it without creative work.

[0167] The above-mentioned specific embodiments have further elaborated in detail the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above-mentioned are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. It is particularly pointed out that for those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A thermal runaway detection method, characterized in that: include: Acquire battery cell data, and acquire a first detection result based on the battery cell data and a preset first parameter threshold group; Acquire pressure data in the battery pack, and acquire a second detection result based on the pressure data in the battery pack and a preset second parameter threshold group; A fusion judgment is performed based on the first detection result and the second detection result to obtain a thermal runaway detection result.

2. A thermal runaway detection method according to claim 1, characterized in that: The obtaining of the battery cell data, and obtaining a first detection result based on the battery cell data and a preset first parameter threshold group, includes: Acquire battery cell data based on the BMS system, wherein the battery cell data includes battery cell temperature data and battery cell voltage data; Acquire a maximum temperature, a maximum temperature difference, and a temperature change rate based on the battery cell temperature data, and acquire a voltage drop and a minimum voltage based on the battery cell voltage; The first parameter threshold group includes a temperature threshold group and a voltage threshold group; judging an abnormal temperature state of the battery based on the maximum temperature, the maximum temperature difference, the temperature change rate and the temperature threshold group; acquiring an abnormal voltage state of the battery based on the minimum voltage, the voltage drop and the voltage threshold group; A first detection result is acquired based on the abnormal temperature state and the abnormal voltage state.

3. A thermal runaway detection method as claimed in claim 2, characterized in that: The abnormal voltage state includes a first voltage state and a second voltage state; the voltage threshold group includes a first voltage threshold and a second voltage threshold; and obtaining the abnormal voltage state of the battery based on the minimum voltage value, the voltage drop and the voltage threshold group includes: If the minimum voltage value is less than or equal to the first voltage threshold, and the duration of the minimum voltage value being less than or equal to the first voltage threshold exceeds a preset first time threshold, the abnormal voltage state is the first voltage state; If within a preset second time threshold, the voltage drop is greater than or equal to the second voltage threshold, the abnormal voltage state is the second voltage state.

4. A thermal runaway detection method as claimed in claim 3, characterized in that: The abnormal temperature state includes a first temperature state, a second temperature state, a third temperature state and a fourth temperature state; the temperature threshold group includes a first temperature threshold, a second temperature threshold and a temperature change threshold; and judging the abnormal temperature state of the battery based on the maximum temperature, the maximum temperature difference, the temperature change rate and the temperature threshold group includes: If the maximum temperature is greater than or equal to the first temperature threshold, and the duration during which the maximum temperature is greater than or equal to the first temperature threshold exceeds a preset third time threshold, the abnormal temperature state is the first temperature state; If the temperature change rate is greater than or equal to the temperature change threshold, and the duration of the temperature change rate being greater than or equal to the temperature change threshold exceeds a preset third time threshold, the abnormal temperature state is the second temperature state; If the temperature detection device is in an open circuit state, and the duration of the temperature detection device being in the open circuit state exceeds a preset fourth time threshold, the abnormal temperature state is a third temperature state; If the maximum temperature difference is greater than or equal to the second temperature threshold, and the duration for which the maximum temperature difference is greater than or equal to the second temperature threshold exceeds a preset third time threshold, the abnormal temperature state is a fourth temperature state.

5. A thermal runaway detection method as claimed in claim 4, characterized in that: The acquiring a first detection result based on the abnormal temperature state and the abnormal voltage state includes: If the battery is in a first voltage state and has a first temperature state, the first detection result is that the battery has thermal runaway; If the battery is in the first voltage state and has the second temperature state, the first detection result is that the battery has thermal runaway; If the battery is in the first voltage state and has a third temperature state, the first detection result is that the battery has thermal runaway; If the battery is in the second voltage state and has the first temperature state, the first detection result is that the battery has thermal runaway; If the battery is in the second voltage state and has the second temperature state, the first detection result is that the battery has thermal runaway; If the battery is in the second voltage state and has a fourth temperature state, the first detection result is that thermal runaway occurs in the battery.

6. A thermal runaway detection method according to claim 1, characterized in that: The obtaining of pressure data in the battery pack includes: The pressure data in the battery pack is obtained based on the VCU system; the pressure data includes current pressure and pressure change data.

7. A thermal runaway detection method according to claim 6, characterized in that: The obtaining a second detection result based on the pressure data in the battery pack and a preset second parameter threshold group includes: The second parameter threshold group includes a pressure threshold and a pressure change threshold; When the current pressure is greater than the pressure threshold, the second detection result is that thermal runaway occurs in the battery; When the pressure change rate is greater than the pressure change threshold, the second detection result is that thermal runaway occurs in the battery.

8. A thermal runaway detection method according to any one of claims 1 to 7, characterized in that: The performing a fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result includes: If the BMS system and the VCU system are operating normally, when the first detection result and the second detection result are both that the battery has thermal runaway, the thermal runaway detection result is that the battery has thermal runaway.

9. A thermal runaway detection method according to any one of claims 1 to 7, characterized in that: The performing a fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result includes: If the BMS system is in a failed state, then when the second detection result is that the battery has thermal runaway, the thermal runaway detection result is that the battery has thermal runaway.

10. A thermal runaway detection device, characterized in that: include: A first detection module, a second detection module and a judgment module; The first detection module is used to obtain battery cell data, and obtain a first detection result based on the battery cell data and a preset first parameter threshold group; The second detection module is used to obtain pressure data inside the battery pack, and obtain a second detection result based on the pressure data inside the battery pack and a preset second parameter threshold group; The judgment module is used to perform a fusion judgment based on the first detection result and the second detection result to obtain a thermal runaway detection result.

Images