Battery thermal runaway risk intelligent management method and system

Abstract

The invention discloses a battery thermal runaway risk intelligent management method and system, and the method comprises the steps: matching corresponding cooling liquid cooperative ultrasonic cooling words according to different risk levels, i.e., absorbing heat generated by conventional operation of a battery through employing the higher specific heat capacity of cooling liquid when the risk is low and the working state of the battery is normal; and the heat control of the battery can be realized. In case of risks such as medium and the like, when a multi-dimensional sensing signal of the battery is slightly abnormal, circulation is started, so that the cooling liquid flows to take away heat generated by the battery, and the cooling liquid is excited to be slightly evaporated and vibrated to enhance heat exchange through relatively low-intensity ultrasonic waves so as to uniformize the temperature in the battery module. When the risk is high, the cooling liquid completely immerses the top of the battery to isolate oxygen, the flowing speed of the cooling liquid is increased to rapidly take away heat, high-strength and high-frequency ultrasonic waves are emitted, rapid evaporation and heat absorption of the cooling liquid are enhanced, the temperature is rapidly reduced, and thermal runaway of the battery is avoided.

Description

Technical Field

[0001] The present invention relates to the field of battery safety technology, and in particular to a method and system for intelligent management of battery thermal runaway risks. Background Art

[0002] As a core component of new energy storage technology, lithium batteries play an increasingly important role in modern industry and daily life. However, with the continuous improvement of the energy density of lithium batteries, their safety issues, especially thermal runaway, have become a key factor restricting their large-scale application. Thermal runaway refers to a series of side reactions caused by the excessive temperature inside the lithium battery that cannot be dissipated in time, which may lead to a decline in battery performance and even cause combustion or explosion, posing a serious threat to personnel safety and property.

[0003] The existing thermal runaway prevention and control technologies mainly include preventing excessive temperature rise of the battery through thermal management means under normal operating conditions. After thermal runaway, the spread of thermal runaway and the occurrence of fire are suppressed by enhancing heat dissipation, setting up an insulation layer between batteries, filling inert gas and fire extinguishing agent, etc. The mainstream heat dissipation methods are air cooling, liquid cooling and phase change cooling. Air cooling has low heat dissipation efficiency and cannot cope with the huge heat generated by thermal runaway. Phase change cooling cannot quickly transfer the absorbed heat and occupies too much space. The heat dissipation of indirect liquid cooling is limited by the heat exchange area. Direct liquid cooling, i.e. immersion liquid cooling, directly immerses the battery in a dielectric fluid with high heat capacity and high thermal conductivity to achieve direct contact between the battery and the coolant, thereby providing higher heat transfer efficiency than traditional liquid cooling plates. The two-phase immersion cooling using a lower boiling point coolant can take advantage of the property of absorbing a large amount of heat when the coolant undergoes a phase change, and quickly take away the huge heat generated by the battery in a short time. It is the most promising cooling method to suppress battery thermal runaway.

[0004] The invention patent application with publication number CN108923098 discloses a cooling device for lithium batteries and lithium battery packs, including a shell, the upper and lower ends of the shell are respectively connected with an upper card plate and a lower card plate, and the inner cavity of the shell is divided into a battery installation cavity and a heat dissipation cavity, the left end of the battery installation cavity is plugged with an air inlet pipe, and the right end of the battery installation cavity is plugged with an air outlet pipe, the battery installation groove is evenly provided with battery installation grooves, and a lithium battery is fixedly installed in the battery installation groove, and the coolant can be fully circulated at the bottom of the battery installation cavity through the uniform distribution of the circulating cooling pipe and the bending corner of the circulating cooling pipe to cool the battery pack in the battery installation cavity. Through the present invention, the single lithium battery and lithium battery pack can be fully cooled and dissipated, and the accumulation of heat in the lithium battery can be avoided, resulting in a decrease in the performance of various aspects of the battery. At the same time, the battery temperature can be prevented from being out of control, causing the battery pack to catch fire, which seriously threatens the safety of the user. However, the coolant disclosed in the patent application circulates at the bottom of the battery installation cavity, and cannot quickly take away the huge heat generated by the battery in a short time.

[0005] The invention patent application with publication number CN113611936A discloses a thermal runaway management device for energy storage lithium batteries and its installation control method, including at least two battery cells, a closed container, a temperature sensor, a pressure sensor, a control device, a pressure relief device and a heat dissipation device; at least two battery cells are installed in a closed container, and a coolant is provided in the closed container to submerge at least two battery cells; the temperature sensor and the pressure sensor are arranged inside the closed container, and are respectively communicated with the control device outside the closed container; the heat dissipation device is arranged outside the closed container and attached to the outer wall of the container; the pressure relief device is arranged outside the closed container and is connected to the upper space of the coolant surface, and the control device is communicated with the heat dissipation device and the pressure relief device. The present invention also discloses an installation control method for a battery thermal runaway management device, which is implemented by the above device. The lithium battery is completely submerged in the coolant, and the temperature and pressure of the container are monitored, and the coolant is evaporated to cool the battery to suppress the thermal runaway of the battery. However, the occurrence of battery thermal runaway is often a rapid process, and even the low-boiling-point coolant disclosed in the above patent application is difficult to quickly undergo phase change and absorb heat before thermal runaway occurs. Summary of the invention

[0006] The present invention provides a method for intelligent management of battery thermal runaway risks. The method can, after early identification of thermal runaway risks, initiate corresponding ultrasonic collaborative immersion cooling measures corresponding to different thermal runaway risks, thereby preventing the occurrence and spread of thermal runaway as much as possible.

[0007] The present invention provides a battery thermal runaway risk intelligent management method, comprising: Obtaining multi-dimensional sensor signal data of the battery, wherein the multi-dimensional sensor signal data is obtained by monitoring the entire operation process of the battery, and evaluating the risk level of thermal runaway of the battery based on the multi-dimensional sensor signal data, wherein the risk level includes low risk, medium risk and high risk; When the risk level is low risk, the coolant is controlled to statically immerse 40% to 80% of the battery height; When the risk level is medium risk, the coolant is controlled to immerse 40% to 80% of the battery height, and the coolant is allowed to circulate continuously, and ultrasonic waves are emitted to the coolant at the same time, and the power of the ultrasonic waves is 20 to 200 W and the frequency is 20 to 100 kHz; When the risk level is high risk, the coolant is controlled to completely immerse the battery and the coolant is allowed to circulate continuously, while ultrasonic waves are emitted to the coolant, wherein the power of the ultrasonic waves is 200-500 W and the frequency is 100 kHz-1MHz.

[0008] Preferably, the multi-dimensional sensor signal data includes temperature data, voltage data, battery expansion force data, gas concentration data and acoustic signal data.

[0009] Preferably, when the risk level is low risk, the multi-dimensional sensing signal data are all within a normal range.

[0010] Preferably, when the risk level is medium risk, the expansion force data growth rate exceeds 5 N / s for more than 3 seconds, and the voltage data change rate is within the range of ±0.02 V / s, excluding 0.02 V / s.

[0011] Preferably, when the risk level is high risk, at least two of the following multi-dimensional sensor signal data exist simultaneously: Voltage data change rate ≥ 0.02V / s; Or the temperature data change rate is ≥ 0.2℃ / s; or monitoring gas concentration data, wherein the gas is one or more of CO, H2 or CH4; Or the expansion force data growth rate drops sharply to below 0 N / s within 1 second and then quickly recovers to 0 N / s; Alternatively, acoustic signal data is monitored, where the acoustic signal is expressed in the time domain as a pulse waveform that rapidly rises to a peak value within 1 second and then decays exponentially, with a duration of 1 to 3 seconds.

[0012] Preferably, when the risk level is medium risk, the flow rate of the coolant is 0.1-1 m / s; When the risk level is high risk, the flow speed of the coolant is 1-5 m / s.

[0013] The present invention also provides a battery thermal runaway risk intelligent management system, comprising: Multi-dimensional monitoring module, used to monitor the multi-dimensional sensor signal data obtained during the entire battery operation process; An intelligent control module, for evaluating a risk level of thermal runaway of a battery based on received multi-dimensional sensor signal data, wherein the risk level includes low risk, medium risk and high risk, and issuing a coolant control instruction and an ultrasonic control instruction based on the risk level; A coolant immersion and circulation module, for controlling the coolant to statically immerse 40% to 80% of the battery height when the risk level is low risk, and to immerse 40% to 80% of the battery height when the risk level is medium risk, and to allow the coolant to circulate continuously; and to control the coolant to completely immerse the battery and allow the coolant to circulate continuously when the risk level is high risk; The ultrasonic transmitting module is used to transmit ultrasonic waves to the coolant based on the received ultrasonic control instructions. When the risk level is medium risk, the ultrasonic waves have a power of 20 to 200 W and a frequency of 20 to 100 kHz. When the risk level is high risk, the ultrasonic waves are transmitted to the coolant. The power of the ultrasonic waves is 200 to 500 W and the frequency is 100 kHz to 1MHz.

[0014] Preferably, the cooling liquid immersion and circulation module comprises a cooling liquid immersion module and a cooling liquid circulation module; The coolant immersion module is connected to the coolant circulation module and the ultrasonic emission module respectively, and is used to control the height and flow rate of the coolant based on the circulation of the coolant and the effect of the ultrasonic wave on the coolant. When the risk level is low risk, the coolant is controlled to be statically immersed in 40% to 80% of the battery height. When the risk level is medium risk, the coolant is controlled to be immersed in 40% to 80% of the battery height, and the flow rate of the coolant is controlled to be 0.1 to 1 m / s. When the risk level is high risk, the coolant is controlled to completely immerse the battery, and the flow rate of the coolant is controlled to be 1 to 5 m / s. The coolant circulation module is used to realize continuous circulation of the coolant based on the received coolant control instructions when the risk level is medium risk or high risk, and absorb heat by phase change during the circulation process, wherein the circulation of the coolant is realized by condensation, evaporation and re-liquefaction.

[0015] Preferably, the multi-dimensional monitoring module includes a plurality of sensors, which are distributed in the battery module and monitor temperature data, voltage data, battery expansion force data, gas concentration data and acoustic signal data in real time.

[0016] Preferably, the intelligent control module is used to evaluate the risk level of thermal runaway of the battery based on the obtained multi-dimensional sensor signal data using a machine learning method, independently decide to select and execute a corresponding cooling strategy, and send coolant control instructions and ultrasonic control instructions to the coolant immersion and circulation module and the ultrasonic transmission module respectively based on the cooling strategy.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention matches corresponding coolants and ultrasonic cooling measures according to different risk levels. That is, when the risk is low and the battery is in normal working condition, the coolant's own high specific heat capacity is used to absorb the heat generated by the normal operation of the battery, so as to achieve thermal control of the battery.

[0018] When the risk is medium and the multi-dimensional sensor signal of the battery shows a slight abnormality, the circulation is turned on to allow the coolant to flow and take away the heat generated by the battery. The coolant is stimulated to evaporate slightly by low-intensity ultrasonic waves and vibrate the coolant to enhance heat exchange, so as to even out the temperature inside the battery module.

[0019] When the risk is high, the coolant is allowed to completely immerse the top of the battery to isolate oxygen, the coolant flow rate is increased to quickly remove the heat, and high-intensity and high-frequency ultrasonic waves are emitted to enhance the rapid evaporation of the coolant and the absorption of heat, quickly reduce the temperature, and avoid thermal runaway of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a flow chart of a battery thermal runaway risk intelligent management method proposed by the present invention; Figure 2 It is a schematic diagram of the structure of step 110 of a battery thermal runaway risk intelligent management method proposed by the present invention; Figure 3 It is a schematic diagram of the structure of step 120 of a battery thermal runaway risk intelligent management method proposed by the present invention; Figure 4 It is a schematic diagram of the structure of step 130 of a battery thermal runaway risk intelligent management method proposed by the present invention; Figure 5 It is a schematic diagram of the structure of step 140 of a battery thermal runaway risk intelligent management method proposed by the present invention; Figure 6 It is a schematic diagram of the structure of a battery thermal runaway risk intelligent management system proposed by the present invention.

[0022] Figure 7 It is a schematic diagram of changes in expansion force, voltage and temperature signals during a thermal runaway process of a lithium battery provided by the present invention. DETAILED DESCRIPTION

[0023] The present application provides a battery thermal runaway risk intelligent management method and system for identifying and managing the thermal runaway risk of the battery during the entire operation process of the battery, so as to avoid thermal runaway of the battery as much as possible or prevent thermal runaway from spreading to adjacent batteries and causing fire.

[0024] This application provides a method for intelligent management of battery thermal runaway risk, such as Figure 1 As shown, including: Step 110: Multi-dimensional data monitoring of the entire battery process; like Figure 2 As shown, in this embodiment, the whole battery process refers to the whole process of the battery in normal operation.

[0025] The temperature data provided by the specific embodiment of the present invention obtains the temperature information of the batteries at various positions in the battery module / pack by evenly distributing thermocouples in the battery module / pack, so that thermal runaway of a battery in the battery module / pack can be quickly sensed.

[0026] The voltage data and current data provided by the specific embodiment of the present invention are monitored through electrical connection, including the voltage and current data of each battery module.

[0027] The internal pressure data of the battery provided by the specific embodiment of the present invention is monitored by embedding a pressure sensor in the battery in advance, and the battery is packaged during the production stage to prevent electrolyte leakage. The expansion force data is obtained by arranging a strain or expansion force sensor on the surface of the battery to monitor the expansion behavior of the outer surface of the battery.

[0028] The gas concentration data provided in the specific embodiment of the present invention is monitored by arranging CO2, CO, H2 and CH4 gas sensors inside the battery pack. These gases will be released after the valve is opened due to thermal runaway, so the change in gas concentration can be used as thermal runaway monitoring data.

[0029] The acoustic signal data provided in the specific embodiment of the present invention is monitored by arranging a sound sensor inside the battery pack, and is mainly used to capture the sound signal of the battery thermal runaway valve opening and exhaust, which serves as one of the key indicators for subsequent thermal runaway risk grading.

[0030] Step 120: Analysis of key indicators of thermal runaway; like Figure 3 As described above, based on step 110, the key thermal runaway indicators are extracted and analyzed from the real-time monitored battery power-heat-electricity-gas-acoustic signals, mainly including: Analyze the battery temperature data and perform numerical processing to obtain the battery temperature fluctuation range and temperature rise rate. Battery thermal runaway is often accompanied by a sharp temperature rise. Pay close attention to whether the temperature fluctuation range is within the normal operating temperature of the battery. For example, the normal operating temperature range of lithium batteries is 0℃~45℃. Whether the temperature rise rate is less than 1℃ / s.

[0031] Analyze the battery voltage change data. Due to chemical reactions and material decomposition inside the battery, the battery voltage may gradually or suddenly drop to 0V. Pay close attention to the voltage drop behavior and perform numerical extraction of the voltage drop amplitude.

[0032] Extract the data of the internal pressure and external expansion force of the battery. During thermal runaway, violent chemical reactions occur inside the battery, causing the decomposition of the electrolyte and the reaction between the positive and negative electrodes, producing a large amount of gas. The production of these gases will cause the internal pressure of the battery to increase sharply. As the internal pressure of the battery increases, the battery shell will undergo significant expansion deformation, causing the pressure between the batteries to change significantly. Pay close attention to whether the internal pressure and external expansion force of the battery increase abnormally, and extract and analyze the pressure increase data.

[0033] Analyze the concentration change data of the gas in the battery pack. Lithium batteries will produce various gases such as CO2, CO, H2 and CH4 during thermal runaway. These gases are mainly caused by chemical reactions inside the battery. Therefore, focus on whether the concentration of these gases increases abnormally, and extract and analyze the data of gas concentration increase.

[0034] Extract the acoustic signals in the battery pack. During thermal runaway, the violent reaction inside the battery will produce specific acoustic characteristics, such as the explosion sound when the gas is generated and released, the cracking sound when the battery expands or ruptures, etc. By analyzing the time domain and frequency domain characteristics of these acoustic signals, it can be determined whether the battery has thermal runaway. The sound signal when the safety valve is opened has a pulse waveform, a short duration, and the signal can reach a peak in a very short time. These characteristics can be used for early identification of thermal runaway.

[0035] Furthermore, the multidimensional data extracted above need to be preprocessed through filtering, denoising and other steps to improve data quality, which helps to reduce false alarms and improve the accuracy of the early warning system.

[0036] Step 130: thermal runaway risk assessment and classification; like Figure 4 As shown in the figure, based on the manifestations at different stages of the thermal runaway process, the thermal runaway risk is divided into three levels, including: Low risk: The battery is in normal working condition. The data fed back by the multi-dimensional sensors such as the battery voltage and temperature fluctuate within a reasonable range under normal operating conditions. There are no abnormal signals, and the risk of thermal runaway is extremely low. At this time, the thermal stability of the battery is good, and there is no sign of violent chemical reactions inside the battery. No abnormal changes were detected in the external expansion force of the battery, indicating that the internal structure of the battery is stable, and there is no gas production or expansion.

[0037] Medium risk: The battery signal begins to show slight abnormalities. Based on the order of multi-dimensional signal responses, the expansion force signal growth rate exceeds 5 N / s and lasts for 3s, which is judged to enter medium risk. At the same time, the voltage signal is closely monitored, and the voltage change rate does not exceed 0.02V / s, which is within the medium risk range. There is no obvious fluctuation in the gas signal and the sound signal. The battery voltage fluctuates at this stage, which may be due to changes in the chemical reaction inside the battery or a tiny internal short circuit inside the battery. At this stage, the risk of thermal runaway of the battery is controllable, but it is necessary to pay close attention to the status of the battery to prevent the risk from escalating.

[0038] High risk: When the risk level is high risk, at least two of the following multi-dimensional sensor signal data exist at the same time: the voltage data change rate ≥ 0.02V / s; or the temperature data change rate ≥ 0.2℃ / s; or the gas concentration data is monitored, and the gas is one or more of CO, H2 or CH4; or the expansion force data growth rate drops sharply to below 0N / s within 1s and quickly recovers to 0N / s. ; Or the acoustic signal data is monitored, and the acoustic signal is manifested in the time domain as a pulse waveform that rises rapidly to a peak value within 1s and then decays exponentially, with a duration of 1~3s. In a specific embodiment, multiple key signals of the battery show obvious precursors to thermal runaway. Based on the thermal runaway characteristics, when the voltage change rate ≥ 0.02V / s (corresponding to the occurrence of internal short circuit, the battery has been damaged internally), and the battery surface temperature change rate ≥ 0.2℃ / s, it is considered to enter a high-risk state. Before thermal runaway occurs, the battery temperature rises rapidly and exceeds the normal operating temperature. The battery voltage fluctuates greatly and gradually decreases or drops suddenly to 0V. At the same time, monitor other signals. When the gas sensor detects the appearance of gas signals such as H2 and CO, and the sound sensor detects a pulse waveform, a short duration, and a sound signal that reaches a peak in a very short time, it may be that the safety valve has exploded and the generated gas is exposed to the air. The expansion force drops rapidly due to gas leakage, and the growth rate is negative in a very short time. At this time, thermal runaway is almost inevitable, and it is necessary to immediately warn the outside and take emergency measures to prevent accidents.

[0039] Step 140: Start the ultrasonic coordinated immersion cooling scheme.

[0040] like Figure 5 As shown, on the basis of step 130, different thermal runaway suppression strategies are established based on ultrasonic assisted immersion liquid cooling for different thermal runaway risk levels, including: Low risk: static semi-immersion cooling and ultrasonic are not yet started. Experiments show that when the battery is working normally, immersion cooling can maintain the battery at normal operating temperature with its excellent heat exchange performance without completely immersing the battery. An advanced intelligent control center is used to achieve precise control and timely response to the battery status. According to the real-time data of the battery temperature, the battery immersion depth is finely adjusted between 40% and 80% of the battery height to ensure the overall temperature uniformity of the battery; Medium risk: dynamic semi-immersion cooling, emitting medium to low intensity frequency ultrasound. When the battery signal shows slight abnormalities, such as a slight or local increase in temperature, or a small fluctuation in voltage, it indicates that the battery has a certain risk of thermal runaway. At this stage, start dynamic immersion cooling, emit medium to low intensity ultrasound, and finely adjust the battery immersion depth to between 40% and 80% of the battery height. The dynamic flow immersion coolant takes away more heat, and the flow rate can be calculated based on the specific immersion liquid properties, immersion volume, and battery heat generation. The flow rate range is 0.1 to 1 m / s. The power of medium to low intensity ultrasound is generally in the range of 20 to 200 W, and the medium to low frequency is controlled in the range of 20 to 100 kHz, which can effectively improve the heat exchange efficiency without causing excessive local vibration or generating too many bubbles; High risk: dynamic full immersion, emitting high-intensity frequency ultrasound. At this point, thermal runaway events will be difficult to avoid and the risk is extremely high. It is urgent to increase the cooling efforts, immerse the coolant to completely submerge the top of the battery, and flow to take away the heat, with a flow rate range of 1~5 m / s. High-intensity frequency ultrasound enhances the rapid evaporation and heat absorption of the coolant, and absorbs the short-term huge heat generated by the thermal runaway of the battery through the phase change of the coolant. At this time, the ultrasonic power can be appropriately increased to the range of 200~500 W, and the frequency is increased to above 100 kHz and below 1MHz. At the same time, according to different battery strengths, the power is finely adjusted to prevent damage to the battery. At the same time, the coolants are all flame retardant, which can quickly extinguish fires after thermal runaway occurs and prevent the spread of thermal runaway.

[0041] The specific embodiment of the present invention also provides a battery thermal runaway risk intelligent management system, such as Figure 6 As shown, it includes a multi-dimensional monitoring module, an intelligent control module, a coolant immersion module, a coolant circulation module and an ultrasonic emission module.

[0042] The multi-dimensional monitoring module provided in a specific embodiment of the present invention includes multiple sensors, which are distributed in the battery module, monitor temperature data, voltage data, battery expansion force data, gas concentration data and acoustic signal data in real time, accurately capture any abnormal signals related to thermal runaway, and transmit the data to the intelligent control module.

[0043] The intelligent control module provided in a specific embodiment of the present invention is used to evaluate the risk level of thermal runaway of the battery based on the received multi-dimensional sensor signal data, wherein the risk level includes low risk, medium risk and high risk, wherein coolant control instructions and ultrasonic control instructions are issued based on the risk level.

[0044] In a specific embodiment, the intelligent control module is used to evaluate the risk level of thermal runaway of the battery based on the obtained multi-dimensional sensor signal data using a machine learning method, autonomously decide to select and execute the corresponding cooling strategy, and send a coolant control instruction and an ultrasonic control instruction to the coolant immersion and circulation module and the ultrasonic emission module respectively based on the cooling strategy. The intelligent control module can flexibly adjust the ultrasonic emission intensity, the circulation flow rate of the coolant, and the immersion depth of the coolant to ensure dynamic response according to the change of the battery state.

[0045] The coolant immersion module provided in the specific embodiment of the present invention is connected to the coolant circulation module and the ultrasonic emission module. According to the risk level of thermal runaway, the coolant circulation module controls the coolant circulation speed and the intensity of the ultrasonic effect on the coolant, so as to flexibly adjust the battery immersion depth and the coolant flow rate. In low-risk situations, the battery is statically immersed with a medium immersion depth. In medium- and low-risk situations, the immersion depth is medium and the flow rate is slow to avoid overcooling. In high-risk conditions, the coolant will completely cover the battery and flow quickly to ensure that heat can be quickly absorbed and the spread of thermal runaway can be suppressed.

[0046] Specifically, the coolant immersion module is used for control based on the coolant circulation module and the ultrasonic emission module. When the risk level is low risk, the coolant is controlled to statically immerse 40%~80% of the battery height; when the risk level is medium risk, the coolant is controlled to immerse 40%~80% of the battery height, and the flow rate of the coolant is controlled to be 0.1~1 m / s; when the risk level is high risk, the coolant is controlled to completely immerse the battery, and the flow rate of the coolant is controlled to be 1~5 m / s to prevent the coolant from evaporating too fast due to the flow rate.

[0047] The coolant circulation module provided in the specific embodiment of the present invention ensures that the coolant can circulate continuously, continuously taking away the heat generated by the battery, and cools and condenses the evaporated coolant through the heat exchange equipment, so that it is reliquefied and recycled, thereby maintaining the effectiveness of the coolant and avoiding excessive local temperature.

[0048] Specifically, the coolant circulation module is used to realize continuous circulation of the coolant based on the received coolant control instructions when the risk level is medium risk or high risk, and absorb heat by phase change during the circulation process, wherein the circulation of the coolant is realized by condensation, evaporation and re-liquefaction.

[0049] The ultrasonic emission module provided in the specific embodiment of the present invention enhances the cooling effect through ultrasonic waves of different frequencies and intensities. In the medium and low risk state, the ultrasonic wave does not work or has a slight effect to avoid excessive evaporation of the coolant. As the risk level increases, the intensity and frequency of the ultrasonic wave increase, promoting the rapid evaporation and heat absorption of the coolant, thereby accelerating the dissipation of heat to match different cooling needs.

[0050] Specifically, the ultrasonic transmitting module is used to transmit ultrasonic waves to the coolant based on the received ultrasonic control instructions. When the risk level is medium risk, the ultrasonic waves have a power of 20 to 200 W and a frequency of 20 to 100 kHz. When the risk level is high risk, the ultrasonic waves are transmitted to the coolant. The power of the ultrasonic waves is 200 to 500 W and the frequency is 100 kHz to 1MHz.

[0051] Furthermore, the coolant has excellent thermal conductivity and dielectric properties, can quickly conduct heat and is non-conductive, ensuring the safety of the battery assembly. Its boiling point is moderate, avoiding excessive evaporation in low-risk situations and reducing pressure increase; while in high-risk situations, it can accelerate evaporation through the action of ultrasound to achieve efficient heat dissipation.

[0052] like Figure 7 As shown in the figure, it shows the changes of expansion force, voltage, and temperature signals over time during the process of entering thermal runaway under normal conditions. The first signal to show data changes is the expansion force signal, followed by the voltage and temperature signals. Therefore, the expansion force signal and voltage signal are used as the judgment criteria for entering a medium-risk state. Voltage, temperature, gas and other signals are used as the main signs of entering a high-risk state. At this time, the safety valve has been opened, the integrity of the battery structure has been destroyed, and the risk of thermal runaway has increased sharply or thermal runaway is about to occur.

[0053] Based on the above description, the intelligent management method and system for battery thermal runaway risk proposed in the present invention can effectively identify early battery thermal runaway signals under various complex operating conditions and take corresponding blocking measures. It can intelligently adjust different cooling measures and dynamically adjust the immersion depth, flow rate, and frequency and intensity of the ultrasonic wave of the coolant according to real-time monitoring data. Ultimately, it provides efficient and safe thermal management for the battery pack, reduces the risk of battery fire or explosion, and improves the safety and reliability of the battery.

[0054] The battery thermal runaway risk intelligent management method and system provided by the specific embodiment of the present invention have the following advantages: 1. Real-time and sensitive. Through various sensors, the multi-dimensional data of battery power, heat, electricity, gas and sound can be obtained, which can monitor the status data of the battery in real time throughout the entire life cycle, sensitively obtain the early signals of battery thermal runaway and quickly perform immersion suppression according to the pre-set algorithm.

[0055] 2. Intelligent classification. The intelligent control module can intelligently classify the multi-dimensional signals collected in real time according to the different status data of battery thermal runaway, automatically adjust the ultrasonic collaborative immersion cooling measures, and manage and deal with different thermal runaway risks with less energy cost.

[0056] 3. Efficient heat dissipation. The ultrasonic collaborative immersion cooling system adopted by the present invention can maximize the heat generated by the battery by enhancing the phase change heat of the cooling liquid through ultrasonic waves, and even out the temperature difference between battery packs, thereby reducing the risk of thermal runaway.

[0057] 4. Safe and reliable. After the battery thermal runaway occurs, the present invention quickly allows the coolant to completely immerse the battery and flow dynamically, which can isolate oxygen. In addition, the coolant is flame-retardant, which can avoid the generation of thermal runaway flames and greatly ensure the safety of personnel.

[0058] The embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referenced to each other.

[0059] The above embodiments are used to explain the present invention, rather than to limit the present invention. It should be understood that the specific implementation methods can be appropriately adjusted or improved according to different application scenarios, usage conditions and equipment requirements. For example, parameters such as the type of coolant, the frequency of the ultrasonic wave, and the arrangement of the sensor can be optimized according to actual needs. Within the spirit of the present invention and the protection scope of the claims, any modifications and changes made to the present invention fall within the protection scope of the present invention.

Claims

1. A battery thermal runaway risk intelligent management method, characterized in that: include: Obtaining multi-dimensional sensor signal data of the battery, wherein the multi-dimensional sensor signal data is obtained by monitoring the entire operation process of the battery, and evaluating the risk level of thermal runaway of the battery based on the multi-dimensional sensor signal data, wherein the risk level includes low risk, medium risk and high risk; When the risk level is low risk, the coolant is controlled to statically immerse 40% to 80% of the battery height; When the risk level is medium risk, the coolant is controlled to immerse 40% to 80% of the battery height, and the coolant is allowed to circulate continuously, and ultrasonic waves are emitted to the coolant at the same time, and the power of the ultrasonic waves is 20 to 200 W and the frequency is 20 to 100 kHz; When the risk level is high risk, the coolant is controlled to completely immerse the battery and the coolant is allowed to circulate continuously, while ultrasonic waves are emitted to the coolant, wherein the power of the ultrasonic waves is 200-500 W and the frequency is 100 kHz-1MHz.

2. The battery thermal runaway risk intelligent management method according to claim 1, characterized in that: The multi-dimensional sensor signal data includes temperature data, voltage data, battery expansion force data, gas concentration data and acoustic signal data.

3. The battery thermal runaway risk intelligent management method according to claim 1 or 2, characterized in that: When the risk level is low risk, the multi-dimensional sensing signal data are all within a normal range.

4. The battery thermal runaway risk intelligent management method according to claim 2, characterized in that: When the risk level is medium risk, the expansion force data growth rate exceeds 5 N / s for more than 3s, and the voltage data change rate is within the range of ±0.02V / s, excluding 0.02 V / s.

5. The battery thermal runaway risk intelligent management method according to claim 2, characterized in that: When the risk level is high, at least two of the following multi-dimensional sensor signal data exist at the same time: Voltage data change rate ≥ 0.02V / s; Or the temperature data change rate is ≥ 0.2℃ / s; or monitoring gas concentration data, wherein the gas is one or more of CO, H2 or CH4; Or the expansion force data growth rate drops sharply to below 0 N / s within 1 second and then quickly recovers to 0 N / s; Alternatively, acoustic signal data is monitored, where the acoustic signal is expressed in the time domain as a pulse waveform that rapidly rises to a peak value within 1 second and then decays exponentially, with a duration of 1 to 3 seconds.

6. The battery thermal runaway risk intelligent management method according to claim 1, characterized in that: When the risk level is medium risk, the flow rate of the coolant is 0.1~1 m / s; When the risk level is high risk, the flow speed of the coolant is 1-5 m / s.

7. A battery thermal runaway risk intelligent management system, characterized in that: include: Multi-dimensional monitoring module, used to monitor the multi-dimensional sensor signal data obtained during the entire battery operation process; An intelligent control module, for evaluating a risk level of thermal runaway of the battery based on the received multi-dimensional sensor signal data, wherein the risk level includes low risk, medium risk and high risk, and issuing a coolant control instruction and an ultrasonic control instruction based on the risk level; A coolant immersion and circulation module, for controlling the coolant to statically immerse 40% to 80% of the battery height when the risk level is low risk, and to immerse 40% to 80% of the battery height when the risk level is medium risk, and to allow the coolant to circulate continuously; and to control the coolant to completely immerse the battery and allow the coolant to circulate continuously when the risk level is high risk; The ultrasonic transmitting module is used to transmit ultrasonic waves to the coolant based on the received ultrasonic control instructions. When the risk level is medium risk, the ultrasonic waves have a power of 20 to 200 W and a frequency of 20 to 100 kHz. When the risk level is high risk, the ultrasonic waves are transmitted to the coolant. The power of the ultrasonic waves is 200 to 500 W and the frequency is 100 kHz to 1MHz.

8. The battery thermal runaway risk intelligent management system according to claim 7, characterized in that: The coolant immersion and circulation module comprises a coolant immersion module and a coolant circulation module; The coolant immersion module is connected to the coolant circulation module and the ultrasonic emission module respectively, and is used to control the height and flow rate of the coolant based on the circulation of the coolant and the effect of the ultrasonic wave on the coolant. When the risk level is low risk, the coolant is controlled to be statically immersed in 40% to 80% of the battery height. When the risk level is medium risk, the coolant is controlled to be immersed in 40% to 80% of the battery height, and the flow rate of the coolant is controlled to be 0.1 to 1 m / s. When the risk level is high risk, the coolant is controlled to completely immerse the battery, and the flow rate of the coolant is controlled to be 1 to 5 m / s. The coolant circulation module is used to realize continuous circulation of the coolant based on the received coolant control instructions when the risk level is medium risk or high risk, and absorb heat by phase change during the circulation process, wherein the circulation of the coolant is realized by condensation, evaporation and re-liquefaction.

9. The battery thermal runaway risk intelligent management system according to claim 7, characterized in that: The multi-dimensional monitoring module includes a plurality of sensors, which are distributed in the battery module and monitor temperature data, voltage data, battery expansion force data, gas concentration data and acoustic signal data in real time.

10. The battery thermal runaway risk intelligent management system according to claim 7, characterized in that: The intelligent control module is used to evaluate the risk level of thermal runaway of the battery based on the obtained multi-dimensional sensor signal data using a machine learning method, independently make decisions to select and execute corresponding cooling strategies, and send coolant control instructions and ultrasonic control instructions to the coolant immersion and circulation module and the ultrasonic transmission module respectively based on the cooling strategy.

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