JP2023545632A - Thermal runaway detection system for batteries inside the housing and how to use it - Google Patents

Abstract

A battery thermal runaway detection sensor system for use within a battery enclosure housing one or more batteries. The system has at least one gas sensor for detecting exhaust conditions of the battery cells and providing real-time sensed output. The microcontroller determines power management and signal conditioned output based on the concentration of a particular battery exhaust gas based on the sensed output from the at least one gas sensor. A method of using such a sensor system is also described.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of U.S. Application No. 17/021,711, filed on September 15, 2020, and U.S. Provisional Application No. 63, filed on July 1, 2021. No. 202,962, the entire contents of each of which are incorporated herein by reference.

The present disclosure relates generally to detection systems for detecting battery failures, and more specifically to batteries within an enclosure, such as batteries used in electric vehicles (FIG. 2(a)), or stationary battery energy The present invention relates to a detection system for detecting thermal runaway in a storage system (FIG. 2(b)). The present disclosure also relates to a method of detecting thermal runaway in a battery using such a system.

As lithium-ion battery technology improves, the energy density of batteries continues to increase, which increases the risk of battery failure. Thermal runaway of lithium-ion batteries is a serious safety issue for electric vehicles. For example, Global Technical Regulation No. 20 proposed by the United Nations on Electric Vehicle Safety (EVS) requires a five-minute advance warning of a dangerous situation caused by thermal runaway.

Referring to Figures 1(a) and 1(b), thermal runaway in lithium-ion batteries occurs when an exothermic reaction occurs within the failed cell that increases the internal temperature, thereby sustaining the internal decomposition reaction and causing the cell to decompose. It is a process that involves the sudden release of decomposed electrolytes and gaseous products, which in many cases can lead to a fire. In modern lithium batteries, the risk of explosion can be reduced by designing them to incorporate controlled vent locations within the cell (see Figure 4), but the risk of fire and explosion due to thermal runaway remains mostly unsolved in liquid electrolyte lithium-based batteries.

Returning to Figures 1(a) and 1(b), certain triggers and abuse conditions can cause batteries, e.g., lithium-ion batteries, to destroy or fail, which can lead to thermal runaway. be. Thermal runaway can be caused by, for example, external short circuits, internal short circuits (particles, dendrites, discrete failures, shocks/punctures), overcharging, overdischarging, external heating, or overheating (self-heating). As the temperature rises, gas is generated. Safe results can be obtained if heat dissipation occurs faster than heat generation.

However, if unchecked or if heat cannot be dissipated faster than it is generated, it can result in a rapid temperature rise, release of flammable and harmful gases in the exhaust, flames, and possibly an explosion. . This can be particularly problematic for vehicles with large battery systems, especially battery electric vehicles and fixed storage devices, as shown in Figure 3, where thermal runaway of a single cell (Figure 4) can engulf the entire pack. This can lead to a cascade of thermal runaway events, resulting in catastrophic fires and the release of harmful gases. Although a battery pack can be configured to passively accommodate some failed cells and meet EVS regulations, thermal runaway propagation can still occur. Therefore, it is important to detect cells that undergo thermal runaway within the pack.

Sensors have been developed to detect thermal runaway. However, simple gas sensors, such as hydrocarbon sensors, can only detect electrolyte gas concentrations and are subject to substantial drift as well as cross-sensitivity to other gases, resulting in short-lived thermal It is a runaway detection sensor.

Therefore, there is a need for a robust early detection system for detecting thermal runaway in mobile and stationary applications that is fast and reliable.

There is no admission that any references cited herein constitute prior art. The applicant expressly reserves the right to contest the accuracy and validity of the documents and information cited.

By identifying attributes of initial cell exhaust that are shared across multiple design types and responding to failed cell exhaust gases, the electrochemical structure, cell packaging (cylindrical, prismatic, or pouch), cell A detection system is disclosed that addresses the challenge of fast and robust thermal runaway detection within a battery enclosure that is generally independent of size and battery configuration (series/parallel).

During a thermal runaway decomposition reaction, the cell converts substantial cathode and electrolyte materials into gas, and the pressurized gas mixture is released for several seconds when the failed cell is in a high charge state (Figure 1(b)). Discharge over a time span. Among typical cell chemistries such as lithium-manganese-cobalt-oxide (NMC) batteries, lithium cobalt oxide (LCO), and lithium iron phosphate (LFP) batteries, thermal runaway testing It shows the release of several gases including carbon and hydrogen. Please refer to FIG. 5. Carbon dioxide is generally evolved during the oxidation reaction of carbonate solvents, hydrogen is generally released as a product of the reduction of water obtained from the combustion reaction with carbon monoxide and/or free lithium, and methane and ethane compounds are , is also present from the reduction reaction of the electrolyte and ethylene carbonate at the lithiated anode.

Also disclosed is the use of such a system to detect (e.g., early detection) thermal runaway and thereby help prevent cell-to-cell propagation of thermal runaway, e.g., originating from a single cell. . In one embodiment, cell exhaust is detected. In one embodiment, thermal runaway is detected. In one embodiment, thermal runaway decomposition products are detected.

In other examples of the present disclosure, at least one additional sensor is provided for detecting secondary conditions of the battery and providing information in real time regarding the rate of progression of cell exhaust and thermal runaway, including pressure or temperature; The microcontroller provides a rate of progression of thermal runaway based on information provided by the secondary sensor. At least one additional sensor can detect pressure or temperature within the battery compartment housing to determine the rate of progress of exhaust/thermal runaway. A sensor housing may be provided to enclose the at least one sensor and at least one secondary sensor. The outputs from the primary and secondary gas sensors make it possible to distinguish between electrolyte leaks and exhaust/thermal runaway. System software is embedded within the sensor microcontroller and can determine whether a thermal runaway threshold level is exceeded and send an alarm to the battery management microcontroller or charging system controller.

In yet other exemplary embodiments, the threshold level for thermal runaway is selected from: (i) a carbon dioxide level greater than about 10,000 ppm; (ii) a hydrogen level greater than about 40,000 ppm; (iii) a carbon dioxide level greater than the lower explosive limit; (iv) a hydrogen level greater than the lower explosive limit; and (v) any combination of them. A multi-chip printed circuit board can be provided that is attached to a battery management controller printed circuit board. To provide a power management system that enables high speed data acquisition modes during charging/discharging of an active battery system and reduced acquisition rates/lower power modes when the battery system is neither charging nor discharging. I can do it. The detection system may send a wake-up command to the main battery system controller upon detection of exhaust/thermal runaway. The sensor system can include two or more hydrogen sensors, two or more carbon monoxide sensors, two or more carbon dioxide sensors, and any combination of any of the foregoing for redundancy in safety-critical applications. A plurality of selected gas sensors may be included. The detection system may also include a humidity sensor, a pressure sensor, a temperature sensor, or any combination thereof.

In another exemplary embodiment, a method is provided for detecting a thermal runaway condition of a battery within a battery housing. The method includes providing a detection system as described above; measuring and/or analyzing one or more gases exhausted from a battery; and determining that the analyzed gas level is and determining whether the level is equal to or higher than a predetermined threshold level indicating runaway. The gas being analyzed can include hydrogen, carbon monoxide, carbon dioxide, or any combination thereof.

This Summary is not intended to identify essential features of the claimed subject matter or for use in determining the scope of the claimed subject matter. It is to be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide an overview or framework for understanding the nature and features of the present disclosure.

The accompanying drawings are incorporated into and constitute a part of this specification. It is understood that the drawings illustrate only some examples of the present disclosure and that other examples or combinations of various examples not specifically illustrated in the drawings may still be within the scope of the present disclosure. sea bream. Embodiments will be explained in more detail by using the drawings.

FIG. 3 is a flow diagram showing the progress of thermal runaway. It is a chart of thermal runaway and temperature. This is a typical battery pack for electric vehicles. 1 is a diagram of a typical battery pack within an energy fixation storage enclosure; FIG. A battery thermal runaway detector is shown. A typical battery cell is shown before and after thermal runaway. FIG. 2 is a diagram of gases released from a thermal runaway event in cells with different electrochemical configurations, namely LCO/NMC, NMC, and LFP. Figure 3 is a plot of a cascading thermal runaway propagating through a pack enclosure where the first cell triggered thermal runaway in several adjacent cells. The plot shows hydrogen concentration increasing immediately after the initial event and pressure increasing slightly within the enclosure more than 1 minute after the event when gas expansion exceeds the pumping capacity of the pack level. This is a plot of the onset of thermal runaway showing a rapid increase in carbon dioxide concentration within the enclosure. 1 is a schematic diagram of a thermal runaway management system.

In describing the illustrative, non-limiting embodiments illustrated in the drawings, specific terminology is used for purposes of clarity. However, this disclosure is not intended to be limited to the particular terms so chosen, and each particular term refers to all techniques that operate in a similar manner to accomplish a similar purpose. It should be understood that equivalents are included. Some embodiments are described for illustrative purposes, and the description and claims are not limited to the illustrated embodiments; other embodiments not specifically shown in the drawings are also contemplated by this invention. It will be understood that this may be within the scope of the disclosure.

A battery thermal runaway detector is pre-positioned within a typical battery housing cavity, as shown in FIG. 3, for example. The housing completely surrounds one or more battery modules, each battery module having one or more battery cells arranged in parallel or series with each other. The battery cells of each module are in electrical communication with adjacent cells, and the battery module is in electrical communication with each adjacent module. A battery controller is in communication with each battery module and/or battery cell. The battery controller can operate each battery cell directly or through a module, such as turning the cell on/off or controlling the voltage output of each cell.

The enclosure protects the battery cells and modules from water, debris, and protects the user and occupants from electrical hazards within the enclosure. The enclosure void volume (volume of space within the enclosure) can vary from just a few liters to more than 200 liters and typically contains air. Battery housings typically include venting features that include one or more small openings to allow pressure equalization inside and outside the housing to prevent strain and damage to the pack. These openings are usually protected with a hydrophobic membrane that allows air exchange but prevents liquid water from flowing directly into the enclosure. The enclosure may also include a valve or similar device to allow overpressure from thermal runaway to safely vent the enclosure, reducing the risk of explosion and harmful debris.

Referring to FIG. 9, a thermal runaway detector or detection system 100 is shown according to one non-limiting example embodiment of the present disclosure. Detection system 100 resides within the cell housing cavity as in FIG. 3 and includes a primary detector, here a gas detector 110. Detection system 100 also includes a pressure sensor 112, a relative humidity (RH) sensor 114, and/or a temperature sensor 116.

In one embodiment of any of the detection systems described herein, primary gas detector 100 includes one or more sensors for detection of decomposition products formed during thermal runaway.

For example, in one embodiment of any of the detection systems described herein, the primary gas detector 110 includes one or more sensors, in one embodiment, a CO ₂ sensor, a carbon monoxide (CO) sensor, HF sensor, _H2 gas sensor, and/or water vapor sensor.

In one embodiment of any of the detection systems described herein, primary gas detector 110 includes a CO ₂ sensor, a CO sensor, an HF sensor, an H ₂ gas sensor, and a water vapor sensor.

In one embodiment of any of the detection systems described herein, primary gas detector 110 includes a _CO2 sensor, a CO sensor, an HF sensor, and an _H2 gas sensor.

In another embodiment of any of the detection systems described herein, the primary gas detector 110 includes a CO ₂ sensor, a CO sensor, an H ₂ gas sensor, and a water vapor sensor.

In another embodiment of any of the detection systems described herein, the primary gas detector 110 includes a CO ₂ sensor, a CO sensor, and an H ₂ gas sensor.

In another embodiment of any of the detection systems described herein, the primary gas sensor 110 examines the inherent physical properties of the sensed gas without chemically interacting with the gas and provides a reliable and robust primary sensor.

In another embodiment of any of the detection systems described herein, the primary gas detector 110 is configured to detect a cell prior to thermal runaway (e.g., during initial cell evacuation of SEI decomposition and electrolyte gas products). further including one or more secondary gas sensors for detection of one or more gases exhausted from the air.

For example, in one embodiment of any of the detection systems described herein, the primary gas detector 110 detects methane, ethane, oxygen, nitrogen oxides, volatile organic compounds, esters, hydrogen sulfide, sulfur oxides. , ammonia, chlorine, propane, ozone, ethanol, hydrocarbons, hydrogen cyanide, flammable gases, combustible gases, toxic gases, corrosive gases, oxidizing gases, and/or reducing gases. Further including one or more secondary gas sensors.

In another embodiment of any of the detection systems described herein, the primary gas detector 110 is CH ₄ , C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , diethyl carbonate (DEC), One or more secondary _gas sensors for detecting dimethyl carbonate (DMC), ethylene _carbonate (EC), ethyl methyl carbonate ( _EMC ), _C4H10 , _C3H6 , _C3H8 and/or _POF3 further including.

In one embodiment of any of the detection systems described herein, gas detector 100 includes one or more primary sensors for detection of decomposition products formed during thermal runaway and one or more primary sensors for detection of decomposition products formed during thermal runaway; and one or more secondary gas sensors for detection of one or more gases exhausted from the cell (eg, during initial cell evacuation of decomposition and electrolyte gas products).

Detectors/sensors 110-116 are positioned around the housing, and any suitable combination of detectors and/or sensors 110-116 may be utilized.

Thermal runaway detection system 100 also includes a voltage regulator 120 that provides and regulates sufficient power to operate sensors 110 - 116 , a microcontroller or microprocessor 118 , and a communications transceiver 122 . Sensor elements 110 - 116 are electrically connected to a microcontroller 118 within detection system 100 . Microcontroller 118 interprets the sensor output from each of sensors 110-116 and provides the signal conditioning necessary to convert the raw sensor signals to engineering values for each component. The values are then transmitted to communications transceiver 122, which provides a data stream of sensor information to a battery management system master controller or other electronic monitoring system.

The _CO2 gas sensor 110, when used as one of the primary gas sensors 110, detects the carbon dioxide level within the enclosure (Fig. (less than seconds). Background concentration levels of carbon dioxide are typically less than 1,000 ppm, and during battery cell pumping conditions these concentrations can easily exceed 60,000 ppm within the enclosure, as shown in Figure 8. provides a very robust gas signal for detection. If the exhaust velocity in the exhaust often exceeds 200 m/s, the diffusion of carbon dioxide within the housing cavity occurs very rapidly and reaches the gas sensor 110 within 2 seconds, regardless of the proximity of the sensor to the exhaust cell. do.

In one embodiment of any of the detection systems described herein, the primary gas sensor 110 for the detection of _CO2 is an infrared (eg, near-dispersive infrared) spectroscopic sensor.

For example, in one embodiment of any of the detection systems described herein, gas sensor 110 provides an output to processing device 118, which determines whether the sensed condition exceeds a predetermined threshold. or whether there is a rapid change in the sensed condition.

In one embodiment of any of the detection systems described herein, the predetermined threshold for detection of carbon dioxide concentration that signals the triggering of a thermal runaway event is greater than about 10,000 ppm, about 20,000 ppm. greater than about 1,000 ppm, such as greater than about 30,000 ppm, greater than about 40,000 ppm, greater than about 50,000 ppm, greater than about 60,000 ppm, or greater than about 75,000 ppm. In one embodiment of any of the detection systems described herein, the predetermined threshold for detection of carbon dioxide concentration that signals the triggering of a thermal runaway event is greater than about 10,000 ppm.

Accordingly, in one embodiment of any of the detection systems described herein, the system detects that the concentration of carbon dioxide detected by the sensor is greater than about 10,000 ppm, greater than about 20,000 ppm, greater than about 30,000 ppm. A thermal runaway event is indicated when the temperature is greater than about 1,000 ppm, such as greater than about 40,000 ppm, greater than about 50,000 ppm, greater than about 60,000 ppm, or greater than about 75,000 ppm. In one embodiment of any of the detection systems described herein, the system indicates that a thermal runaway event has occurred if the concentration of carbon dioxide detected by the sensor is greater than about 10,000 ppm. .

Similarly, the background concentration of hydrogen in the atmosphere is typically about 200-300 ppb. Under battery cell pumping conditions, the hydrogen concentration inside the battery housing can easily exceed 140,000 ppm, also providing a robust signal-to-noise ratio for gas detection, as shown in FIG.

In one embodiment of any of the detection systems described herein, the primary gas sensor 110 for H ₂ detection is a thermal conductivity sensor.

In one embodiment of any of the detection systems described herein, the predetermined threshold for detection of hydrogen concentration that signals the triggering of a thermal runaway event is greater than about 300 ppb, greater than about 1 ppm, about greater than about 200 ppm, such as greater than 100 ppm, greater than about 1,000 ppm, greater than about 10,000 ppm, greater than about 40,000 ppm, greater than about 50,000 ppm, greater than about 100,000 ppm, or greater than about 150,000 ppm. In one embodiment of any of the detection systems described herein, the predetermined threshold for detection of hydrogen concentration that signals the triggering of a thermal runaway event is greater than about 40,000 ppm.

Accordingly, in one embodiment of any of the detection systems described herein, the system detects that the concentration of hydrogen detected by the sensor is greater than about 300 ppb, greater than about 1 ppm, greater than about 100 ppm, greater than about 1,000 ppm. , greater than 200 ppm, such as greater than about 10,000 ppm, greater than about 50,000 ppm, greater than about 100,000 ppm, or greater than about 150,000 ppm, indicating that a thermal runaway event has occurred. In one embodiment of any of the detection systems described herein, the system indicates that a thermal runaway event has occurred when the concentration of hydrogen detected by the sensor is greater than 40,000 ppm.

In one embodiment of any of the detection systems described herein, the system indicates that a thermal runaway event has occurred when the concentration of hydrogen detected by the sensor is above a lower explosive limit (4%). .

In one embodiment of any of the detection systems described herein, the system detects when the concentration of CO detected by the sensor exceeds its hazardous limit and/or its lower explosive limit (12.5%). , indicating that a thermal runaway event has occurred.

The use of thermal conductivity principles for hydrogen and non-dispersive infrared measurements of _CO2 primary sensors is a robust and absolute measurement device with limited cross-sensitivity to other gases, thereby making such devices is ideal for this application where there is little or no opportunity to recalibrate or repair the device in the field. This is because measurement principles are generally selected based on the physical behavior inherent to these gas molecules, but not chemically interacting with the target gas or other gases in the environment.

In one embodiment of any of the detection systems described herein, the secondary gas sensor is a MO _x or peristaltic-based sensor (eg, for detection of hydrocarbons).

Pressure sensor 112 detects the gas pressure level within the cavity of the battery housing. The nominal air pressure within the enclosure approximates atmospheric pressure. During thermal runaway evacuation, the pressure may rise rapidly if the evacuation phase involves high energy, such as in the case of a cell at 100% charge as shown in FIG. However, the initial pressure rise can be very low, especially for small cells or cells with much lower charge states, as shown in FIG. Depending on the enclosure exhaust system, increases in gas pressure or temperature can provide information regarding the rate of thermal runaway. The pressure sensor 112 is small, low cost, has a fast time response with low power consumption, but has a slow exhaust phenomenon that allows the battery housing exhaust system to release trapped gas at a rate that offsets gas production. have been shown to provide insufficient data. However, when used to complement gas sensor 110, pressure sensor 112 provides valuable insight into the progression of thermal runaway as it cascades from the starting cell to adjacent cells within the enclosure, as shown in FIG. where a continuous increase in hydrogen gas concentration and the associated pressure spike indicates that thermal runaway will progress to additional cells, leading to cascading failure of the pack.

Temperature sensor 116 detects the temperature within the housing cavity and, like pressure sensor 112, can be used in conjunction with gas sensor 110 to estimate the rate of progression of thermal runaway (FIG. 6). The gradual increase in temperature associated with thermal runaway in each successive cell indicates that the reaction has stopped or that the introduction of water or extinguishing agents, active cooling, dilution air or nitrogen, and electrical isolation of the suspected cell or providing critical data in determining if the situation is progressing at a rate that requires immediate safety measures, including but not limited to providing protective measures, including but not limited to discharge.

In one embodiment, temperature sensor 116 detects a temperature in a range of about 100°C to about 1200°C, such as about 600°C to about 1000°C.

Relative humidity sensor 114 is used in conjunction with gas sensor 110 to monitor the humidity within the cavity of the enclosure and observe substantial changes in water vapor within the enclosure indicative of water vapor formation due to decomposition reaction products. You can also.

Detection system 100 may be utilized in a variety of suitable applications. In the embodiments shown in FIGS. 2(a) and 3, the detection system 100 is implemented in a vehicle having a battery housing, a power distribution unit, and a battery controller and/or motor control unit (MCU). The battery case may be configured with a plurality of battery cells and housed within the battery case.

Each of the sensors 110-116 outputs a sensed signal to a processing device, such as a microcontroller 118. Microcontroller 118 converts analog sensor signals into engineering values and transmits data, such as in the form of alarm or output signals, to the battery management system via wired or wireless transceiver 122. The microcontroller 118 can also determine whether the values from the sensors 110-116 exceed critical thresholds for that sensor to indicate cell evacuation, as well as whether the sensors 110-116 are operating normally. Algorithms can be provided to determine whether the system is working within specifications. Detection system 100 may utilize redundant sensors 110-116 to meet safety index levels.

One or more of the sensors 110-116 are positioned in free space within the vehicle's battery enclosure (FIG. 3) such that the sensors 110-116 are in communication with the air gap proximate the battery and/or battery compartment. (e.g., gas or pressure communication) and receive and detect conditions resulting from battery cell exhaust. The sensors 110-116 provide outputs to a processing device 118 that determines whether the sensed condition is a predetermined threshold (i.e., a threshold that, if exceeded, indicates that thermal runaway-based cell evacuation has begun). It can be determined whether an excess is exceeded or if there is a rapid change in the sensed condition. The entire system 100, including sensors 110-116, microcontroller 118, regulator 120, and transceiver 122, can all be housed in a single sensor housing and located in one location within the battery compartment. In another embodiment, the system 100 comprises separate devices, each having its own housing, each housing positioned at a separate location within the battery compartment, including surface mounting to battery management system electronics. It can be.

As illustrated and described, the detection system addresses the problem of robust detection of thermal runaway in lithium-ion batteries, where outgassing precursors to thermal runaway occur over time spans of seconds or hours. It is possible. The detection system measures multiple physical parameters of an outgassing event, allowing detection of rapid thermal runaway as well as slower events. Multiple detection technology reduces the risk of false positive and negative errors and provides sufficient redundancy to meet market safety requirements. The system can measure at least hydrogen and/or carbon dioxide concentrations, supplemented with air pressure and/or temperature and humidity within the enclosure.

In other variations, the detection system may also include hydrocarbon detection of electrolytes including methane, ester, and ethane gases. During the initial cell evacuation prior to thermal runaway, the exhausted gases contain sufficient concentrations of H ₂ , CO, CO ₂ , and hydrocarbons to be detected by the individual sensors. By combining those elements into a single sensor platform with signal conditioning and analysis, we can determine with relative certainty that an event is a single cell undergoing thermal runaway, and by simultaneously monitoring the gas It is possible to determine the difference between a less urgent electrolyte leak and a more urgent thermal runaway condition. The use of thermal conductivity principles for hydrogen and non-dispersive infrared measurement of _CO2 sensors is a robust absolute measurement device with limited cross-sensitivity to other gases, thereby making such a device It is ideal for this application where there is little or no opportunity to recalibrate or repair the device.

Referring more specifically to FIG. 6, an exemplary runaway is illustrated. In this illustrative example, thermal runaway cascades from one cell to an adjacent cell. Starting from T=0, the battery system operates under normal conditions, with hydrogen level 150, temperature 160, and pressure 170 all normal. During a first time period, T=1, the first single battery cell of the first battery module undergoes thermal runaway. As a result, the battery cell releases gas, in this case hydrogen. The hydrogen sensor of gas detector 110 measures the hydrogen level and has a sensed gas level output. The hydrogen sensor sends a sensed gas level output to the microcontroller 118. Additionally, pressure sensor 112 detects pressure and has a sensed pressure output. The pressure sensor then sends the sensed pressure output to the microcontroller 118. Additionally, temperature sensor 116 measures the temperature within the enclosure and provides a sensed temperature output. Temperature sensor 116 sends a sensed temperature output to microcontroller 118.

Sensors 110-116 immediately transmit sensed outputs to microcontroller 118 in real time without delay or manual intervention. Sensors 110-116 may transmit sensed outputs to microcontroller 118 continuously or in intermittent random or predetermined periods (eg, several times per second).

In the exemplary embodiment of FIG. 6, a cascading thermal runaway event is shown propagating through the pack enclosure where the initial cell triggers thermal runaway in adjacent cells. Microcontroller 118 receives sensed gas, pressure, and temperature outputs from gas, pressure, and temperature sensors 110, 112, and 116, respectively. At T=1, hydrogen gas level 150 and pressure 170 both exhibit spikes. However, the temperature 160 only increases slightly. Venting within the battery housing allows the pressure 170 to quickly dissipate and return to normal levels. However, hydrogen exits more slowly and remains at high levels. Based on these conditions and receiving the sensed output, microcontroller 118 determines that at least the first battery cell has undergone a thermal runaway event and generates an alarm signal that it sends to the battery controller. In response, the battery controller may, for example, indicate to the operator that servicing is required, reduce the voltage requirements of the battery module, or control the battery to prevent the battery from becoming too hot. , can take the first response.

In the exemplary embodiment of FIG. 6, at T=2, another cell undergoes thermal runaway. The microprocessor 118 now determines, based on the sensed outputs from the gas sensor 150 and pressure sensor 160, that there has been another spike in gas and pressure, respectively, and that the temperature has again increased slightly. The pressure returns to normal again fairly quickly due to the evacuation conditions, but the temperature and hydrogen levels continue their rising pattern. Therefore, microprocessor 118 determines that another thermal runaway event has occurred and sends another alarm signal to the battery controller. The battery controller may respond by continuing the same response or by, for example, reducing the alert response time, e.g. by indicating that immediate repair is required, or by turning off one or more of the battery modules. can be escalated. Microcontroller 118 determines that there is an additional spike at T=3,4. The various levels of gas, temperature and pressure may vary based on pumping conditions and the particular thermal runaway event. For example, following T=4, the pressure may drop when the housing hydrophobic vent fails, but a spike occurs with each successive cell thermal runaway event in which an additional cell fails within the housing. do. The microcontroller 118 or battery controller can further determine that there is a cascading pattern of events and take additional responsive actions. Response actions can be sent from the battery controller to the microcontroller 118 via the transceiver 122, which then controls the operation of the cells and modules.

Referring to FIG. 7, another exemplary thermal runaway event is illustrated. Here, system 100 includes a gas sensor 110, here a hydrogen sensor, and a pressure sensor 112. At T=1, the hydrogen concentration 150 rose immediately after the first evacuation, and then at T=2 (1 minute after T=1), gas expansion exceeded the evacuation capacity of the pack level within the enclosure. Sometimes the pressure 170 increases slightly. Therefore, at T=1, microprocessor 118 generates an alert that thermal runaway has begun. The pressure rise at T2 in Figure 7 shows the delayed response of the pressure signal in this example, where hydrogen gas is present above the lower exposure limit at T1, but the pressure increases for more than 1 minute. It does not increase substantially during the period.

Referring to FIG. 8, yet another exemplary embodiment is shown. Here, gas detector 110 is a carbon dioxide sensor. The plot shows that the carbon dioxide concentration 150 increases rapidly within the enclosure, while the pressure 170 remains the same and the temperature 160 shows a slight increase. At T=2, microcontroller 118 determines that thermal runaway has occurred and generates and sends an alarm to the battery controller.

Accordingly, the microcontroller 118 uses sensed outputs from the gas, pressure, RH, and/or temperature sensors 110, 112, 114, 116, respectively, to detect a thermal runaway event or other condition within the battery enclosure. Determine whether it exists. Microcontroller 118 may base its determination on a single sensed output or a combination of sensed outputs. For example, the microcontroller 118 may determine that thermal runaway may be occurring based on the presence of gas spikes alone and then reference the sensed pressure output and/or the sensed temperature output. Thermal runaway events can be detected throughout the pack by using a combination of gas measurements to determine the initial thermal runaway event and monitoring pressure or temperature increases to assess the magnitude of the event. You can determine if it is cascaded to additional cells. High gas concentration levels and simultaneous increases in temperature or pressure within the pack indicate that the countermeasure is not localizing the event to a single cell and is generating an alert that escalates the response. There is. For example, an initial alert may be to notify the vehicle owner to take the vehicle to a repair facility as soon as possible, and an escalating warning may be to notify vehicle occupants to pull the vehicle to the side of the road and It may be a notification to exit and the BMS will shut down the vehicle except for the heat exchanger system to slow the process. However, if the temperature and pressure do not increase, the microcontroller 118 can determine that the thermal event has stopped, a single cell or group of cells has been identified, and will not generate an alert to escalate the response. Thus, in the example given, the alert would continue to notify the vehicle owner to have the vehicle serviced.

Note that a microcontroller 118 is provided to receive the sensed output, determine spikes, and send an alarm to the battery controller via transceiver 122. However, the microcontroller operations may instead be performed by the battery controller itself, and the sensed outputs may be sent to the battery controller via a transceiver. The response action signal may be sent directly from the battery controller to the cell via transceiver 122.

Advantages of the detection system 100 include, for example, using known, validated, and field-proven sensor technology, and leveraging specific combinations of sensors to detect the chemical and thermal physics of phenomena associated with thermal runaway events. This includes allowing multiple layers of detection mechanisms related to chemical properties. The system requires little customization to suit various xEV housing sizes/cell configurations/electrochemical structures. The system also has a very fast time response (typically 3-5 seconds) for environments where rapid response with minimal risk of detector leakage/false positives is required to reliably detect thermal runaway. has. The system is compact and can operate in multiple modes to reduce parasitic power consumption when the battery housing is not actively charging or discharging. These modes can be either driving or charging, where fast detection is important and power consumption is less important, or active mode where consumption is important and reducing the sampling rate to reduce the power consumption of the device. In a passive mode that can be reduced, information received from the battery management system can be utilized to control within the sensor assembly 100.

The systems and methods of the present invention include operation by one or more processing devices, including microprocessor 118. Note that the processing device may be any suitable device, such as a processor, microprocessor, controller, application specific integrated circuit (ASIC), etc. The processing device may be used in combination with other suitable components such as displays, memory or storage devices, input devices (touch screens), wireless modules (for RF, Bluetooth, infrared, WiFi, etc. devices). Information may be stored on computer media such as a computer hard drive, or any other suitable data storage device that can be located on or in communication with the processing device. The entire process is performed automatically by the processing device without manual interaction. Accordingly, unless otherwise indicated, processes may be performed in substantially real time without delay or manual action.

In another aspect, the present disclosure relates to a method of detecting thermal runaway of a battery (eg, detecting thermal runaway of one or more battery cells) within an enclosure.

In one embodiment, the method includes:
(i) providing a detection system according to any of the embodiments described herein within a battery housing;
(ii) measuring and/or analyzing one or more gases exhausted from the battery;
(iii) determining whether the analyzed gas level is greater than or equal to a predetermined threshold level indicative of thermal runaway of the battery.

In one embodiment, the gas being analyzed includes hydrogen, carbon monoxide, carbon dioxide, or any combination thereof.

In one embodiment, any of the detection systems and/or methods described herein include: i) receiving a sensor signal; ii) evaluating the sensor signal against a threshold; or iii) results of the evaluation. or any combination of the foregoing.

In another embodiment, none of the detection systems and/or methods described herein monitor ambient gas within the ambient gas environment.

It will be apparent to those skilled in the art having the benefit of the teachings presented in the foregoing description and associated drawings that modifications, combinations, subcombinations, and variations can be made without departing from the spirit or scope of the disclosure. Probably. Similarly, the various examples described may be used individually or in combination with other examples. Those skilled in the art will appreciate various combinations of examples not specifically described or illustrated herein that fall within the scope of this disclosure. In this regard, it is to be understood that this disclosure is not limited to the specific examples described, and that the examples of this disclosure are intended to be illustrative rather than restrictive.

As used in this specification and the appended claims, the singular forms "a," "an," and "the" refer to plural referents unless the context clearly dictates otherwise. include. Similarly, the adjective "another" when used to introduce an element is intended to mean one or more elements. The terms “comprising,” “including,” “having,” and similar terms are inclusive so that there may be additional elements other than those listed. is intended.

Additionally, if the method described above or the method claim below does not explicitly require an order in which its steps follow, or in some cases, no order is required based on the description or claim language, any No particular order is intended to be inferred. Similarly, if a method claim below does not explicitly recite a step mentioned in the above description, it should not be assumed that the claim requires that step.

Claims (20)

A battery thermal runaway detection sensor system for use within a battery enclosure containing one or more batteries, the sensor system comprising:
(i) at least one primary gas sensor for detecting a thermal runaway condition of a battery cell and providing a real-time sensed output;
(ii) determining a power management and signal conditioned output for a particular battery thermal runaway gas concentration based on the sensed output from the at least one primary gas sensor and providing the sensed output in real time; A battery thermal runaway detection sensor system, comprising: a controller; The detection system of claim 1, wherein the system further comprises a secondary gas sensor for detecting an electrolyte leak condition. 3. Detection system according to claim 1 or 2, wherein the primary gas sensor comprises one or more of a _CO2 sensor, a CO sensor, an HF sensor, a _H2 sensor, and/or a water vapor sensor. 4. Detection system according to any one of claims 1 to 3, wherein the primary gas sensor comprises one or more of a CO ₂ sensor, a CO sensor and/or an H ₂ sensor. The secondary gas sensor detects methane, ethane, oxygen, nitrogen oxides, volatile organic compounds, esters, hydrogen sulfide, sulfur oxides, ammonia, chlorine, propane, ozone, ethanol, hydrocarbons, hydrogen cyanide, flammable gases, and explosions. Detection according to any one of claims 2 to 4, comprising one or more sensors for the detection of a toxic gas, a toxic gas, a corrosive gas, an oxidizing gas, a reducing gas, or a combination of any of the foregoing. system. The secondary gas sensor detects CH ₄ , C ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylene carbonate (EC), ethyl methyl carbonate (EMC), According to any one of claims 2 to 5, comprising one or more sensors for C ₄ H ₁₀ , C ₃ H ₆ , C ₃ H ₈ , POF ₃ or any combination of any of the foregoing. detection system. 7. The detection system according to any one of claims 2 to 6, wherein the at least one primary gas sensor detects the level of hydrogen gas, carbon monoxide gas and/or carbon dioxide gas within the battery compartment housing. further comprising at least one additional sensor for detecting secondary conditions of the battery and providing information in real time regarding the rate of progress of cell exhaust and thermal runaway, including pressure or temperature; 8. Detection system according to any one of claims 1 to 7, providing the rate of progress of the thermal runaway based on information provided by a secondary sensor. 9. The detection system of claim 8, wherein the at least one additional sensor detects pressure or temperature within the battery compartment housing to determine the rate of progress of the exhaust/thermal runaway. 10. A detection system according to any preceding claim, further comprising a sensor housing surrounding the at least one sensor and the at least one secondary sensor. 11. A detection system according to any one of claims 1 to 10, wherein the output from the primary gas sensor and the secondary gas sensor allows a distinction between electrolyte leakage and exhaust/thermal runaway. 12. System software embedded within the sensor microcontroller determines whether a thermal runaway threshold level is exceeded and sends an alarm to the battery management microcontroller or charging system controller. Detection system according to paragraph 1. The threshold level for thermal runaway is
(i) a carbon dioxide level greater than about 10,000 ppm;
(ii) a hydrogen level greater than about 40,000 ppm;
(iii) carbon dioxide concentration above the lower explosive limit;
13. The detection system of claim 12, wherein the detection system is selected from (iv) a hydrogen level above its lower explosive limit; and (v) any combination thereof. 14. Detection system according to any one of claims 1 to 13, consisting of a multi-chip printed circuit board attached to a battery management controller printed circuit board. Claims comprising a power management system that enables high speed data acquisition modes during charging/discharging of an active battery system and that enables reduced acquisition rates/lower power modes when the battery system is neither charging nor discharging. 15. The detection system according to any one of 1 to 14. 16. A detection system according to any preceding claim, wherein the system is capable of sending a wake-up command to the main battery system controller upon detection of exhaust/thermal runaway. The sensor system may include two or more hydrogen sensors, two or more carbon monoxide sensors, two or more carbon dioxide sensors, and any combination of any of the foregoing for redundancy in safety-critical applications. 17. A detection system according to any one of claims 1 to 16, comprising a plurality of gas sensors selected from: 18. A detection system according to any preceding claim, wherein the system further comprises a humidity sensor, a pressure sensor, a temperature sensor, or any combination thereof. A method for detecting a thermal runaway state of a battery in a battery housing, the method comprising:
(i) providing a detection system according to any one of claims 1 to 18 within the battery housing;
(ii) measuring and/or analyzing one or more gases exhausted from the battery;
(iii) determining whether the analyzed gas level is at or above a predetermined threshold level indicative of thermal runaway of the battery. 20. The method of claim 19, wherein the analyzed gas comprises hydrogen, carbon monoxide, carbon dioxide, or any combination thereof.