A new energy vehicle charging facility thermal runaway grading protection system and a protection method thereof

Abstract

The application discloses a kind of charging facilities thermal runaway grading protection system and its protection method in new energy charging technical field, including charging facilities ontology, thermal field perception unit, flue gas perception unit, power supply loop cutting unit, fire extinguishing medium release unit and control unit;Control unit determines the first parameter level of the first type of parameter representing thermal state and the second parameter level of the second type of parameter representing flue gas state, to query the pre-stored mapping relationship with the combination of two levels, determine the target disposal level from at least three disposal levels of progressive intervention intensity and execute disposal action, wherein the first disposal level outputs prompt information and does not interrupt the charging process, the second disposal level cuts off the power supply loop, and the third disposal level releases fire extinguishing medium;The application solves the technical problems that single parameter independent triggering cannot determine the evolution stage of thermal runaway and the disposal action lacks intermediate level in the related art.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle charging technology, and more specifically, to a graded protection system for thermal runaway of new energy vehicle charging facilities and its protection method, as well as a computer-readable storage medium. Background Technology

[0002] With the continuous growth of new energy vehicle ownership, the scale of charging infrastructure and the power level of single charging piles are increasing in tandem. The charging power of DC charging facilities is constantly increasing, and the heat density of power devices inside the charging facilities is rising accordingly. Thermal runaway during charging has become one of the main sources of risk for the safe operation of charging facilities. Thermal runaway is usually not an instantaneous event, but a gradual process that evolves from electrical anomalies, heat accumulation, flue gas release, to open flame. The intervention methods and acceptable intervention intensity vary at each stage of the evolution process.

[0003] For the safety protection of charging facilities, existing solutions mainly focus on electrical quantity protection, installing overcurrent protection and leakage protection devices in the power supply circuit. When the voltage, current, or leakage current exceeds the set value, the power supply circuit is cut off. Based on this, the industry has also developed improved solutions that involve installing smoke detectors or temperature sensors in the charging facilities, and triggering power cut-off and fire extinguishing devices when smoke or temperature exceeds their respective thresholds.

[0004] Long-term practice has revealed that while the above-mentioned solutions can reduce fire risk to some extent, they suffer from several fundamental technical flaws. First, the evolution of thermal runaway cannot be determined by the exceeding of limits of a single parameter. Temperature increases may originate from normal heat generation during high-power charging, and smoke may arise from external environmental interference. When each parameter triggers independently, it is difficult to simultaneously address both false alarms and missed alarms, leaving the protection settings caught in a dilemma between sensitivity and sluggishness. Second, the response actions only include power outage and fire extinguishing, lacking an intermediate level of intervention intensity. Once triggered, charging service is completely interrupted, making it impossible to reconcile the contradiction between power supply availability and protection sensitivity. Furthermore, there is a lack of means to confirm and progressively intervene in the thermal runaway process, which continues to release heat even after power is cut off. Third, the coordinated execution of power outage and fire extinguishing relies on a single control path. When the control unit malfunctions or the control power supply is interrupted, both the power outage and fire extinguishing actions lose their trigger source, causing the entire protection system to fail.

[0005] How to implement protective interventions with appropriate strength at different stages of thermal runaway evolution, while taking into account both protection sensitivity and charging service continuity, and ensuring that protective actions are still available when control paths fail, has become a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a graded protection system and method for thermal runaway of charging facilities, which overcomes the defects of existing technologies such as misjudgment of thermal runaway evolution stages due to independent triggering of single parameters, interruption of charging services due to lack of intermediate levels of handling actions, and protection failure due to single control paths.

[0007] The objective of this invention is achieved as follows: A graded protection system for thermal runaway in new energy vehicle charging facilities, comprising:

[0008] The charging facility itself includes a charging power module and a charging output circuit for charging the load equipment;

[0009] A thermal field sensing unit is used to collect a first type of parameter characterizing the thermal state of the charging facility body, wherein the first type of parameter is a temperature field related parameter.

[0010] The flue gas sensing unit is used to collect a second type of parameter that characterizes the flue gas state within the charging facility. The second type of parameter is a parameter that is different from the first type of parameter.

[0011] A power supply circuit cutoff unit is connected in series with the power supply circuit of the charging facility body;

[0012] A fire extinguishing medium release unit is installed inside the charging facility body;

[0013] The control unit is communicatively connected to the thermal field sensing unit, the smoke sensing unit, the power supply circuit cutoff unit, and the fire extinguishing medium release unit, respectively.

[0014] The control unit is configured as follows:

[0015] Determine the first parameter level of the first type of parameter and the second parameter level of the second type of parameter;

[0016] The target handling level is determined by querying the pre-stored mapping relationship using the combination of the first parameter level and the second parameter level. The target handling level belongs to at least three handling levels with progressively increasing intervention intensity. The at least three handling levels include a first handling level that outputs prompt information without interrupting the charging process, a second handling level that cuts off the power supply circuit, and a third handling level that releases the extinguishing medium.

[0017] Perform the action corresponding to the target handling level;

[0018] The target treatment level is determined jointly by the first parameter level and the second parameter level.

[0019] Optionally, the pre-stored mapping relationship is a mapping table indexed by the first parameter level and the second parameter level. The control unit is also configured to adjust the target treatment level to a higher treatment level when at least one of the first parameter level and the second parameter level increases; to gradually decrease the target treatment level when both parameter levels fall back and remain for a preset duration; and to maintain the third treatment level after performing the treatment action of the third treatment level until a manual reset signal is received.

[0020] Optionally, the first type of parameter includes at least one of absolute temperature, temperature rise rate, and temperature field spatial gradient; the second type of parameter includes at least one of smoke concentration, smoke concentration growth rate, and gas component concentration, wherein the gas component concentration is carbon monoxide concentration, volatile organic compound concentration, or hydrogen concentration.

[0021] Optionally, the thermal field sensing unit includes an infrared thermal imaging component for acquiring a temperature field image of the charging facility body; the smoke sensing unit includes a smoke concentration sensing component for outputting a smoke concentration signal; the thermal field sensing unit further includes a vehicle data acquisition component, which communicates with the vehicle battery management system via a communication line in the charging output circuit to acquire the vehicle battery temperature and the charging interface temperature, and the temperature rise rate is calculated based on the vehicle battery temperature.

[0022] Optionally, the temperature field image data stream output by the infrared thermal imaging component is divided into a first data stream and a second data stream. The first data stream is transmitted to the control unit to determine the first type of parameter. The second data stream is transmitted to the remote monitoring platform. The remote monitoring platform performs fire point identification and smoke identification on the second data stream and sends the identification results back to the control unit. The control unit corrects the first parameter level based on the returned identification results.

[0023] Optionally, the thermal field sensing unit, the smoke sensing unit, the power supply circuit cut-off unit, and the fire extinguishing medium release unit are all nodes on the communication bus. The control unit polls each node through the communication bus, and the level boundaries in the mapping table are remotely adjusted through the communication bus. When the control unit does not receive a response from any node within a preset heartbeat cycle, it marks the node as a failed node and executes a prompt action corresponding to the first handling level.

[0024] Optionally, the extinguishing medium release unit includes a temperature-sensing trigger, which directly triggers the release of the extinguishing medium when the ambient temperature exceeds the temperature sensing threshold, without going through the control unit; the power supply circuit cut-off unit has overcurrent protection tripping function and leakage protection tripping function independent of the control unit; the system also includes an auxiliary power supply module, which is powered by a backup battery after the external power supply is interrupted, so that the control unit, the thermal field sensing unit and the smoke sensing unit are powered.

[0025] Optionally, at least three treatment levels also include a first intermediate treatment level, the intervention intensity of which is between the first treatment level and the second treatment level. When the treatment action of the first intermediate treatment level is executed, the control unit controls the charging power module to reduce the output power and maintain the charging process. The entry condition of the third treatment level includes that after the treatment action of the second treatment level is executed, at least one of the first type of parameter and the second type of parameter continues to deteriorate within a preset confirmation time.

[0026] A method for thermal runaway protection of new energy vehicle charging facilities is applied to the control unit of the aforementioned graded thermal runaway protection system for charging facilities. The method is executed cyclically according to a preset monitoring cycle. Each preset monitoring cycle includes simultaneously acquiring a first type of parameter collected by a thermal field sensing unit and a second type of parameter collected by a flue gas sensing unit, determining the first parameter level of the first type of parameter and the second parameter level of the second type of parameter, querying a pre-stored mapping relationship using the combination of the two parameter levels, determining the target disposal level from at least three disposal levels with progressively increasing intervention intensity, and executing the disposal action corresponding to the target disposal level. The disposal action of the first disposal level outputs a prompt message without interrupting the charging process, the disposal action of the second disposal level cuts off the power supply circuit, and the disposal action of the third disposal level releases the extinguishing medium. The first parameter level, the second parameter level, and the target disposal level determined in this cycle are stored as a status record as the basis for adjusting the disposal level in the next preset monitoring cycle.

[0027] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention employs a technical approach that uses a combination of two types of heterogeneous parameters to query a pre-stored mapping relationship to determine the response level, executes response actions progressively according to intervention intensity, and retains independent triggering paths on both the power outage and fire extinguishing sides. This ensures that the determination of the thermal runaway evolution stage is based on the combined evidence of the two types of heterogeneous parameters. In the early stages of evolution, only uninterrupted charging prompts and power limiting actions are executed. After evolution confirmation, the process progresses to cutting off the power supply circuit. After the circuit is cut off, the release of the extinguishing medium is initiated based on the deterioration criterion of the confirmation time. Simultaneously, the protective action remains accessible even if any control path fails. This invention solves the technical problems in related technologies where independent triggering with a single parameter cannot determine the thermal runaway evolution stage, where response actions lack intermediate levels, and where protection is unreachable after control path failure. It achieves a balance between protection sensitivity, charging service continuity, and protection accessibility. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a structural block diagram of a graded protection system for thermal runaway of charging facilities according to an embodiment of the present invention.

[0030] Figure 2 This is a flowchart of a method for protecting charging facilities from thermal runaway, according to an embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram illustrating the mapping relationship between the combination of the first parameter level and the second parameter level to the treatment level in an embodiment of the present invention.

[0032] Figure 4 This is a schematic diagram illustrating the state transition of the handling level upgrade and downgrade in an embodiment of the present invention.

[0033] Figure 5 This is a schematic diagram of the layered arrangement of the charging facility body according to an embodiment of the present invention.

[0034] Figure 6 The physical object of the present invention. Figure 1 .

[0035] Figure 7 The physical object of the present invention. Figure 2 .

[0036] Figure 8 The physical object of the present invention. Figure 3 .

[0037] Figure 9 The physical object of the present invention. Figure 4 . Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example

[0040] The overall concept of this embodiment is that thermal runaway of charging facilities is an evolutionary process along the time axis, progressing sequentially from electrical anomalies, heat accumulation, smoke emission, to open flame. The exceeding of limits by any single parameter at any given moment is insufficient to determine the stage of evolution. Temperature increases may be a normal byproduct of high-power charging, and smoke appearance may be due to external environmental interference. Only the combination of the respective levels of thermal field parameters and smoke parameters constitutes a verifiable criterion for the evolution stage. Accordingly, this embodiment organizes protective actions into multiple levels of intervention with progressively increasing intensity. Information-level actions intervene in the early stages of evolution without interrupting charging services; power-level actions reduce until energy supply is cut off after evolution is confirmed; and chemical-level actions release extinguishing media when cutting off energy supply still cannot prevent parameter deterioration. Each level of intervention is determined by the minimum necessary intensity that can be confirmed by the current combination of heterogeneous parameters, thereby simultaneously avoiding the loss of power availability caused by premature cut-off and the loss of safety caused by late intervention.

[0041] Figure 1-9 This is a structural block diagram of a graded protection system for thermal runaway of charging facilities according to an embodiment of the present invention. Figure 1 As shown, the system includes a charging facility body 10, a thermal field sensing unit 20, a smoke sensing unit 30, a power supply circuit cutoff unit 40, a fire extinguishing medium release unit 50, a control unit 60, a remote monitoring platform 70, a communication bus 80, a voice output unit 90, and an indicator unit 91. The control unit 60 is connected to the thermal field sensing unit 20, the smoke sensing unit 30, the power supply circuit cutoff unit 40, and the fire extinguishing medium release unit 50 via the communication bus 80. The voice output unit 90 and the indicator unit 91 are connected to the control unit 60. The remote monitoring platform 70 communicates with the control unit 60 via a wired or wireless network. The thermal field sensing unit 20 contains an infrared thermal imaging component 21, and the smoke sensing unit 30 contains a smoke concentration sensing component 31.

[0042] The charging facility body 10 is an integrated AC / DC charging facility structure, including a charging power module 11, an AC input circuit 12, a charging output circuit 13, and an auxiliary power module 14. The charging power module 11 converts the three-phase AC power from the AC input circuit 12 into high-voltage DC power, which is then output to the electric vehicle, acting as the load device, via the charging output circuit 13. In this embodiment, the input voltage range of the charging power module 11 is 220V to 380V, the output voltage is 1000V, and the output current is 67A. This wide input range design ensures the continuity of power conversion when the grid voltage fluctuates. The AC input circuit 12 constitutes the power supply circuit of the charging facility body 10, and the power supply circuit disconnection unit 40 is connected in series in this circuit. The auxiliary power module 14 draws power from the AC input, and after rectification and conversion, provides low-voltage auxiliary DC power to the control unit 60, the thermal field sensing unit 20, the smoke sensing unit 30, the voice output unit 90, and the indicator unit 91. In this embodiment, the auxiliary DC voltage is 48V. The auxiliary power module 14 also performs equalization and float charging management for the backup battery. After the external power supply is interrupted, the backup battery maintains the power supply for each control and sensing component, ensuring the continuity of monitoring and reporting actions after power failure.

[0043] The thermal field sensing unit 20 is used to collect first-type parameters characterizing the thermal state of the charging facility body 10. In this embodiment, the thermal field sensing unit 20 includes an infrared thermal imaging component 21, which acquires temperature field images inside the charging facility body 10 in a dual-spectrum manner. The temperature measurement range is from -20 degrees Celsius to 150 degrees Celsius, covering the normal operating temperature and the temperature precursor of thermal runaway. It uses Ethernet power supply wiring, eliminating the need for a separate power supply circuit. The control unit 60 extracts the absolute temperature value, temperature rise rate, and temperature field spatial gradient from the temperature field image as first-type parameters. The absolute temperature value is taken as the highest temperature point in the temperature field, the temperature rise rate is obtained by the difference between the highest temperature points in adjacent monitoring periods and then by moving average, and the temperature field spatial gradient is taken as the difference between the highest temperature point and the average value of the temperature field background. The image frame rate of the infrared thermal imaging component 21 is higher than the sampling requirement corresponding to the monitoring period. The latest frame is used in the calculation within each monitoring period to avoid using expired frames. When the infrared thermal imaging component 21 is installed, its field of view covers the power layer area where the charging power module 11 is located. A light-transmitting window is opened on the housing, and the transmittance of the window material is calibrated and written into the configuration parameters during installation. In other embodiments, the thermal field sensing unit 20 includes a point-type temperature sensing component 22, with multiple temperature sensing elements distributed at different locations inside the charging facility body 10, collecting the temperature at their respective locations. The spatial gradient of the temperature field is approximated by the temperature difference between different locations. The thermal field sensing unit 20 can also use a contact temperature measuring element attached to the connection terminal of the charging output circuit 13 to directly collect the temperature of the electrical connection part. The contact resistance heating of the electrical connection part is an important source of heat inside the charging facility, and contact temperature measurement is most sensitive to this heat source.

[0044] In this embodiment, the thermal field sensing unit 20 also includes a vehicle data acquisition component 23. The vehicle data acquisition component 23 communicates with the vehicle battery management system via a communication line in the charging output circuit 13. The charging connection cable has a communication line in addition to the power wire. During charging, the vehicle battery management system periodically reports the battery status according to the charging communication protocol. The vehicle data acquisition component 23 reads the vehicle battery temperature and charging interface temperature from the reported data. The control unit 60 calculates the temperature rise rate based on the difference in vehicle battery temperature readings between adjacent monitoring cycles. This temperature rise rate is used as a first-type parameter in the grading process. The charging interface temperature is used as a source of absolute temperature parameters in the grading process. When both the temperature rise rate on the charging pile side and the temperature rise rate of the vehicle battery are valid, the higher value is used for grading. The earliest precursor to thermal runaway of the vehicle battery is an abnormal rise in the internal temperature of the battery. The thermal field sensing and smoke sensing on the charging pile side lag behind the conduction of heat to the charging pile and the release of smoke, respectively. The vehicle battery temperature acquired via the vehicle-charging pile communication line moves the collection location of the first-type parameter forward to the inside of the battery being charged, further advancing the grading window to the stage before heat is conducted to the charging pile. The charging interface temperature reflects the heating caused by the contact resistance of the charging connection terminals. These terminals are the areas with concentrated contact resistance in the charging circuit, and their temperature complements the temperature field inside the charging pile. Vehicle data is only available during the charging session. In non-charging states or when vehicle-pile communication is interrupted, the vehicle battery temperature does not participate in the rating process. If the data age of this parameter exceeds two monitoring cycles, the most recent valid value is used, triggering a prompt action. Rating regression is then performed by parameters on the charging pile side. In this embodiment, the vehicle data acquisition component 23 is implemented by an edge computing component with a controller area network interface. The adapter board leads out CAN-H and CAN-L lines and connects to the communication terminals of the charging connector, with a communication rate of 500kbps.

[0045] The smoke sensing unit 30 is used to collect a second type of parameter characterizing the smoke state within the charging facility body 10. In this embodiment, the smoke sensing unit 30 includes a smoke concentration sensing component 31, which outputs a smoke concentration signal in PPM, reports it digitally via a communication bus, and also has a local audible and visual alarm function. The response of the smoke concentration sensing component 31 has a rising edge lag; the control unit 60 uses delayed confirmation processing for the concentration signal, confirming an over-limit only when the readings for several consecutive monitoring cycles are higher than the judgment threshold, thus filtering out short-term external interference. In other embodiments, the smoke sensing unit 30 includes a gas concentration sensing component 32, which collects carbon monoxide concentration, volatile organic compound concentration, or hydrogen concentration as the second type of parameter. Before the visible smoke emission during thermal runaway, the lithium battery has already undergone electrolyte decomposition and gas evolution; the rise in gas component concentration precedes the rise in smoke concentration. Using gas concentration as the second type of parameter can shift the judgment window forward.

[0046] In this embodiment, the power supply circuit disconnection unit 40 is a electrically operated shunt trip circuit breaker connected in series with the AC input circuit 12. It has a rated current of 63A, a leakage current of 30mA, a leakage trip time of no more than 0.1 seconds, and an ultimate breaking capacity of 6000A. The power supply circuit disconnection unit 40 receives the tripping command from the control unit 60 via the communication bus and executes the tripping action. It also has independent tripping functions for overcurrent protection and leakage protection, which do not depend on any commands from the control unit 60. The tripping command carries a target status identifier and a redundant check code. The power supply circuit disconnection unit 40 only performs the tripping action after verifying the check code, preventing erroneous tripping caused by bus errors. After tripping, the switch status and circuit current are read back and reported. The control unit 60 uses the zeroing of the circuit current as a confirmation condition for successful tripping. If the zeroing is not confirmed, the tripping command is reissued and an escalation prompt is given.

[0047] In this embodiment, the extinguishing medium release unit 50 is an aerosol fire extinguishing device with an extinguishing medium dosage of 100g, a release time of no more than 14 seconds, and an extinguishing density of 100g to 130g per cubic meter. The extinguishing medium release unit 50 can be triggered by receiving a release command from the control unit 60 via a communication bus, by direct triggering from the temperature-sensitive trigger 51 when the temperature exceeds the threshold, or by a manual button. The temperature-sensitive trigger 51 is a thermally sensitive wire located in the power layer area where the charging power module 11 is located. It directly initiates the release when the ambient temperature exceeds the temperature threshold, bypassing the control unit 60. After an external power supply interruption, the extinguishing medium release unit 50 maintains its command reception and activation capabilities for at least 10 seconds using its internal backup power supply. The nozzle faces the concentrated heat source area of ​​the power layer, and the distance between the nozzle and frequently approached areas is no less than 1.5 meters, while the distance between the nozzle and the protected object is no less than 0.3 meters.

[0048] In this embodiment, the control unit 60 is an embedded main control unit, including a memory 61. The memory 61 pre-stores a mapping table from the combination of the first parameter level and the second parameter level to the handling level. The control unit 60 polls each sensing unit and execution unit via a multi-channel communication interface. The polling is performed at a preset heartbeat cycle. If the control unit 60 does not receive a response from a certain node within the preset heartbeat cycle, it marks the node as a failed node and executes a prompt action corresponding to the first handling level. The prompt content includes the identifier of the failed node. In this embodiment, the communication bus 80 is an RS485 bus, and each unit is connected as a bus node. The voice output unit 90 broadcasts voice prompts during the first handling level action. The indicator unit 91 includes a charging status indicator light and a display screen, which use different colors and flashing patterns to distinguish the charging status, each handling level, and fault information. The remote monitoring platform 70 receives the parameters, levels, and handling status reported by the control unit 60 and sends a threshold setting message to the control unit 60.

[0049] Figure 5This is a schematic diagram of the layered layout of the charging facility body 10. The charging facility body 10 adopts a vertical multi-layer frame structure, with the frame constructed of metal profiles. The upper part is the display and control layer, housing an indicator unit 91, a control unit 60, and a voice output unit 90. The middle part is the power layer, housing a charging power module 11, a power supply circuit cutoff unit 40, and control boards for the charging circuit. The lower part is the auxiliary power layer, housing an auxiliary power module 14 and a backup battery. The thermal field sensing unit 20 and the smoke sensing unit 30 are located above the power layer. The hot smoke generated by thermal runaway flows upward due to buoyancy. Placing the smoke sensing unit above the power layer allows for the interception of smoke characteristics at the earliest point in the smoke diffusion path. The field of view of the thermal field sensing unit covers the power layer from top to bottom, aligning with the nozzle orientation. The nozzle of the extinguishing medium release unit 50 faces the concentrated heat source area of ​​the power layer, meeting the requirements of extinguishing density for agent distribution. This layered layout also spatially isolates the power layer from the display and control layer, ensuring that the human-machine interface of the display layer is not directly threatened by thermal anomalies in the power layer.

[0050] Figure 3This diagram illustrates the mapping relationship between the combination of the first and second parameter levels and the treatment level. The first parameter level is determined based on pre-stored thresholds. The absolute temperature value, temperature rise rate, and temperature field spatial gradient are compared with pre-stored first and second temperature thresholds, respectively. The highest level among these comparisons is taken as the first parameter level. The levels, from lowest to highest, are: normal level, first-level exceedance level, and second-level exceedance level. The second parameter level is determined based on pre-stored first and second concentration thresholds, using the same method as the first parameter level. The smoke concentration growth rate in the second parameter level is obtained by calculating the difference in smoke concentration between adjacent monitoring periods using a moving average. The mapping table uses the first parameter level and the second parameter level as indexes. In this embodiment, the partitioning rules are as follows: Normal charging is maintained when both the first and second parameter levels are normal; the first parameter level is a level 1 over-limit and the second parameter level is normal, entering the first handling level; the first parameter level is a level 2 over-limit and the second parameter level is normal, entering the first intermediate handling level; the first parameter level is a level 1 over-limit and the second parameter level is a level 1 over-limit, entering the first intermediate handling level; the first parameter level is a level 2 over-limit and the second parameter level is a level 1 over-limit or higher, entering the second handling level; the second parameter level is a level 2 over-limit, regardless of the first parameter level, entering the second handling level. When the query result falls within the partition boundary, the higher handling level is selected. Each threshold is remotely adjusted via the communication bus. The adjustment is based on the parameter baseline plus margin under no-load steady-state conditions, multiplied by a correction coefficient according to the charging power range and ambient temperature, so that the margin of the judgment threshold relative to the baseline remains consistent after changes in operating conditions. The level boundary setting is delayed, and different thresholds are used for over-limit judgment and fallback judgment. The threshold for fallback judgment is lower than the threshold for over-limit judgment, and parameter jitter near the threshold is filtered out.

[0051] Figure 2 This is a flowchart of a thermal runaway protection method for charging facilities. The method is executed by the control unit 60, and is performed cyclically according to a preset monitoring cycle. The selected monitoring cycle is no longer than the response time of the slower-responding unit between the thermal field sensing unit and the flue gas sensing unit, ensuring that both types of parameters are valid readings within each cycle.

[0052] Step S202: Simultaneously acquire the first type of parameters collected by the thermal field sensing unit 20 and the second type of parameters collected by the flue gas sensing unit 30. The sampling rates of the first and second types of parameters are different. Timestamp alignment is performed based on the monitoring cycle boundary. For fast-sampling parameters, the most recent valid value at the cycle boundary is used; for slow-sampling parameters, the most recent valid value is used, and the data age is recorded. If the data age exceeds two monitoring cycles, the most recent valid value is used, and a prompt action is triggered. Readings exceeding the sensor's physical range are considered bad pixels, discarded, and filled with the most recent valid value. If bad pixels appear consecutively, the sensing unit is marked as pending inspection. Temperature rise rate parameters use moving averages to suppress noise, and the sliding window covers multiple consecutive monitoring cycles. During the charging session, the vehicle battery temperature and charging interface temperature reported by the vehicle data acquisition component 23 are merged into the first type of parameters after the same timestamp alignment and bad pixel processing.

[0053] Step S204: Determine the first parameter level of the first type of parameter and the second parameter level of the second type of parameter. The classification is performed according to the pre-stored threshold. The highest level result of each comparison path is taken. The hysteresis of the level boundary takes effect during classification. The level is only downgraded when the parameter crosses the fallback threshold from top to bottom.

[0054] Step S206: Query the pre-stored mapping relationship using the combination of the first parameter level and the second parameter level to determine the target handling level. The mapping table is stored in memory 61 in the form of a two-dimensional data table. The query result is compared with the currently executing handling level. If the query result is higher than the current level, the level is switched immediately; if the query result is lower than the current level, the level is not switched temporarily, and the process proceeds to the hold decision.

[0055] Step S208: Execute the action corresponding to the target handling level. The actions for the first handling level include controlling the voice output unit 90 to broadcast prompts, controlling the indicator unit 91 to display changes, reporting to the remote monitoring platform 70 via the communication bus 80, and increasing the acquisition frequency of the first and second types of parameters. No power or switching commands are issued during the first handling level, and the charging process is not interrupted. The actions for the first intermediate handling level include the control unit 60 issuing a power limiting command to the charging power module 11 via the communication bus 80, reducing the charging output power to a preset ratio and maintaining the charging process. The power limiting command is periodically retransmitted to prevent command loss. The actions for the second handling level include issuing a tripping command to the power supply circuit disconnection unit 40, confirming successful tripping by returning the circuit current to zero, and terminating the charging process after tripping. The actions of the third response level include confirming that the power supply circuit is in the disconnected state, issuing a discharge command to the fire extinguishing medium release unit 50, and the fire extinguishing medium is discharged within 14 seconds. During and after the discharge, the backup battery of the auxiliary power module 14 maintains monitoring and reporting. The third response level is maintained after execution and will only exit after receiving a manual reset signal.

[0056] Step S210: Store the first parameter level, second parameter level, and target handling level determined in this cycle as a status record, which will serve as the basis for adjusting the handling level in the next preset monitoring cycle. The status record is stored in a non-volatile storage area, which is not lost when power is off, and is used for post-accident analysis. When the query result is lower than the current level, the parameter combination corresponding to the query result must remain for a preset time before the handling level is gradually lowered, except for cases where the third handling level has been executed.

[0057] The following example illustrates the entire chain of actions during a typical charging process. During charging, if the highest temperature point in the temperature field exceeds the first temperature threshold within a certain monitoring period, while the smoke concentration remains within the normal range, the first parameter level is classified as Level 1 exceedance, and the second parameter level is normal. The system queries the mapping table and enters the first handling level. The voice output unit broadcasts a prompt, the indicator unit changes its display, the sampling frequency increases, and charging continues uninterrupted. Several minutes later, if the temperature rise rate exceeds the second rate threshold and the smoke concentration, after a delay, exceeds the first concentration threshold, the first parameter level becomes Level 2 exceedance, and the second parameter level becomes Level 1 exceedance. The system enters the first intermediate handling level, the charging power module operates with limited power, and the charging process continues. Subsequently, the smoke concentration continues to rise and exceeds the second concentration threshold, the second parameter level becomes Level 2 exceedance, and the system enters the second handling level. The power supply circuit is cut off, and the circuit current is confirmed to return to zero. After the circuit is tripped, if the temperature rise rate remains higher than the second rate threshold and the smoke concentration continues to increase within a preset confirmation time, it is confirmed that heat accumulation has not been suppressed after the energy supply is cut off. The system then enters the third handling level, and the extinguishing medium is released. During each of the aforementioned cycles, parameters, levels, and handling status are simultaneously reported to the remote monitoring platform 70. The complete evolution and intervention sequence are then reconstructed from the status record. In other implementations, if the parameters drop within the confirmation period after the circuit breaker trips, the second handling level is maintained and the system waits for a gradual exit without releasing extinguishing agents, thus avoiding chemical intervention for events that can be suppressed by power outages.

[0058] The dosage of extinguishing agent is calculated based on the extinguishing density and the volume of the protected area. The required dosage G is equal to the product of the extinguishing density ρ and the volume of the protected area V, i.e., G = ρ × V. The extinguishing density is taken as 100g to 130g per cubic meter. When the total amount of agent is 100g, the volume of the protected area that meets the extinguishing density requirement is 0.77 cubic meters to 1 cubic meter. The volume of the protected area corresponding to the power layer inside the charging facility body 10 is less than this value. The agent configuration allows for a margin while meeting the density requirement. The discharge time is no more than 14 seconds to ensure that the extinguishing agent can quickly establish an inhibitory concentration in the later stages of evolution.

[0059] The system has three independent triggering paths on both the power outage and fire extinguishing sides. The first path is the normal triggering of the control unit 60 to trip and release the extinguishing agent via the communication bus 80. The second path is the overcurrent and leakage tripping of the power supply circuit disconnection unit 40 itself. Even if the control unit 60 fails, the circuit current or leakage current exceeding the tripping setting value can still complete the power outage. The third path is the direct triggering of the temperature-sensing trigger 51. When the entire control system fails and the external power supply is interrupted, the thermal wire directly starts the release after the ambient temperature exceeds the temperature sensing threshold. The fire extinguishing medium release unit 50 relies on its internal backup power supply to maintain the ability to receive and start commands for no less than 10 seconds after the power outage. There is no common control link between the three paths. The failure of any one path does not affect the accessibility of the other paths, and a single point failure will not lead to the overall failure of the protection system.

[0060] In this embodiment, the temperature field image data stream output by the infrared thermal imaging component 21 is divided into two paths. The first data stream is transmitted to the control unit 60 for extracting the first type of parameters and participating in local classification. The second data stream is uploaded to the remote monitoring platform 70 via the network. The remote monitoring platform 70 performs fire point identification and smoke identification on the second data stream, and the identification results are sent back to the control unit 60. The control unit 60 corrects the first parameter level based on the returned identification results. If a fire point is identified but the local temperature parameter has not yet exceeded the limit, the first parameter level is corrected to level one exceeding the limit and verified. The local classification constitutes a fast response loop, and the remote identification constitutes a fine confirmation loop. The data sources of the two loops are the same, but the processing paths are independent. The interruption of one data stream does not affect the operation of the other loop.

[0061] In a site scenario consisting of multiple charging facilities, when any charging facility enters the first intermediate handling level or above, the remote monitoring platform 70 issues a preventive load reduction command to the adjacent charging facilities and triggers encrypted monitoring. The adjacent charging facilities reduce their charging output power and increase the collection frequency to reduce the risk of heat propagation and accumulation between adjacent devices.

[0062] In other embodiments, the communication bus 80 is any one or a combination of RS485 bus, CAN bus, or Ethernet, with the wireless channel serving as a backup for the wired channel. The classification logic can be deployed locally in the control unit 60, or it can be executed by the remote monitoring platform 70 to issue the target handling level; the handling action still reaches the execution unit via the local bus. The specific combination of the first and second types of parameters is configured according to the application scenario. DC fast charging facilities emphasize the combination of temperature rise rate and smoke concentration, while energy storage cabinet scenarios emphasize the combination of gas component concentration and temperature field spatial gradient. When the computer program stored in memory 61 is executed by the processor, it implements the steps of the above-described thermal runaway protection method for charging facilities. This computer program can also be stored in a computer-readable storage medium and executed by a device with processing capabilities.

[0063] This invention employs a technical approach that uses a combination of two types of heterogeneous parameters to query a pre-stored mapping relationship to determine the response level, executes response actions progressively according to intervention intensity, and maintains independent triggering paths on both the power outage and fire extinguishing sides. This allows the determination of the thermal runaway evolution stage to be based on combined evidence from the two types of heterogeneous parameters. In the early stages of evolution, only uninterrupted charging prompts and power limiting actions are executed. After evolution confirmation, the process progresses to cutting off the power supply circuit. After the circuit is cut off, the release of the extinguishing medium is initiated based on a deterioration criterion of the confirmation time. Furthermore, the protective action remains accessible even if any control path fails. Therefore, this invention at least solves the technical problems in related technologies where independent triggering by a single parameter cannot determine the thermal runaway evolution stage, where response actions lack intermediate levels, and where protection is unreachable after control path failure. It achieves a technical effect that balances protection sensitivity, charging service continuity, and protection accessibility.

[0064] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A graded protection system for thermal runaway in new energy vehicle charging facilities, characterized in that, include: The charging facility body (10) includes a charging power module (11) and a charging output circuit (13) for charging the load equipment. The thermal field sensing unit (20) is used to collect a first type of parameter characterizing the thermal state of the charging facility body (10), wherein the first type of parameter is a temperature field related parameter; The flue gas sensing unit (30) is used to collect a second type of parameter that characterizes the flue gas state inside the charging facility body (10). The second type of parameter is a parameter that is different from the first type of parameter. The power supply circuit cutoff unit (40) is connected in series with the power supply circuit of the charging facility body (10); A fire extinguishing medium release unit (50) is installed inside the charging facility body (10); The control unit (60) is communicatively connected to the thermal field sensing unit (20), the smoke sensing unit (30), the power supply circuit cut-off unit (40), and the fire extinguishing medium release unit (50), respectively. The control unit (60) is configured as follows: Determine the first parameter level of the first type of parameter and the second parameter level of the second type of parameter; The target handling level is determined by querying the pre-stored mapping relationship using the combination of the first parameter level and the second parameter level. The target handling level belongs to at least three handling levels with progressively increasing intervention intensity. The at least three handling levels include a first handling level that outputs prompt information without interrupting the charging process, a second handling level that cuts off the power supply circuit, and a third handling level that releases the extinguishing medium. Perform the action corresponding to the target handling level; The target treatment level is determined jointly by the first parameter level and the second parameter level.

2. The graded protection system for thermal runaway of new energy vehicle charging facilities according to claim 1, characterized in that, The pre-stored mapping relationship is a mapping table indexed by the first parameter level and the second parameter level; The control unit (60) is also configured to: When at least one of the first parameter level and the second parameter level increases, the target treatment level is adjusted to a higher treatment level; When both the first parameter level and the second parameter level fall back and remain at a preset duration, the target processing level is gradually lowered. After the third level of treatment has been performed, the third level of treatment is maintained until a manual reset signal is received.

3. The graded protection system for thermal runaway of new energy vehicle charging facilities according to claim 1 or 2, characterized in that, The first type of parameter includes at least one of absolute temperature, temperature rise rate, and temperature field spatial gradient; the second type of parameter includes at least one of smoke concentration, smoke concentration growth rate, and gas component concentration, wherein the gas component concentration is carbon monoxide concentration, volatile organic compound concentration, or hydrogen concentration.

4. The graded protection system for thermal runaway of new energy vehicle charging facilities according to claim 3, characterized in that, The thermal field sensing unit (20) includes an infrared thermal imaging component (21), which is used to acquire the temperature field image of the charging facility body (10); the smoke sensing unit (30) includes a smoke concentration sensing component (31), which is used to output a smoke concentration signal; the thermal field sensing unit (20) also includes a vehicle data acquisition component 23, which communicates with the vehicle battery management system via the communication line in the charging output circuit (13) to acquire the vehicle battery temperature and the charging interface temperature, and the temperature rise rate is calculated based on the vehicle battery temperature.

5. The graded protection system for thermal runaway of new energy vehicle charging facilities according to claim 4, characterized in that, The temperature field image data stream output by the infrared thermal imaging component (21) is divided into a first data stream and a second data stream. The first data stream is transmitted to the control unit (60) to determine the first type of parameter. The second data stream is transmitted to the remote monitoring platform (70). The remote monitoring platform (70) performs fire point identification and smoke identification on the second data stream and sends the identification results back to the control unit (60). The control unit (60) is also configured to correct the first parameter level based on the returned identification results.

6. The graded protection system for thermal runaway of new energy vehicle charging facilities according to claim 1 or 2, characterized in that, The thermal field sensing unit (20), the smoke sensing unit (30), the power supply circuit cut-off unit (40), and the fire extinguishing medium release unit (50) are all nodes on the communication bus. The control unit (60) polls each node through the communication bus. The level boundaries in the mapping table are remotely adjusted via the communication bus. If the control unit (60) does not receive a response from any node within a preset heartbeat cycle, it marks the node as a failed node and executes a prompt action corresponding to the first handling level.

7. The graded protection system for thermal runaway of new energy vehicle charging facilities according to claim 1 or 2, characterized in that, The extinguishing medium release unit (50) includes a temperature-sensing trigger (51), which directly triggers the release of the extinguishing medium when the ambient temperature exceeds the temperature-sensing threshold, without going through the control unit (60). The power supply circuit cutoff unit (40) has overcurrent protection tripping function and leakage protection tripping function independent of the control unit (60); The thermal runaway graded protection system for the new energy vehicle charging facility also includes an auxiliary power module (14), which is powered by a backup battery after the external power supply is interrupted.

8. The graded protection system for thermal runaway of new energy vehicle charging facilities according to claim 1 or 2, characterized in that, The at least three treatment levels also include a first intermediate treatment level, the intervention intensity of which is between the first treatment level and the second treatment level. When the treatment action of the first intermediate treatment level is performed, the control unit (60) controls the charging power module (11) to reduce the output power and maintain the charging process. The entry condition for the third treatment level includes that after the treatment action of the second treatment level is executed, at least one of the first type of parameter and the second type of parameter continues to deteriorate within a preset confirmation time.

9. A method for protecting charging facilities from thermal runaway, applied to the control unit (60) of the graded protection system for thermal runaway of new energy vehicle charging facilities according to any one of claims 1 to 8, characterized in that, The method is executed cyclically according to a preset monitoring cycle, and the method includes the following steps in each preset monitoring cycle: The first type of parameters collected by the thermal field sensing unit (20) and the second type of parameters collected by the flue gas sensing unit (30) are acquired simultaneously. Determine the first parameter level of the first type of parameter and the second parameter level of the second type of parameter; The pre-stored mapping relationship is queried using the combination of the first parameter level and the second parameter level, and the target treatment level is determined from at least three treatment levels with progressively increasing intervention intensity. Execute the response action corresponding to the target response level, wherein the response action of the first response level outputs a prompt message and does not interrupt the charging process, the response action of the second response level cuts off the power supply circuit, and the response action of the third response level releases the extinguishing medium. The first parameter level, the second parameter level, and the target treatment level determined in this cycle are stored as status records and used as the basis for adjusting the treatment level in the next preset monitoring cycle.

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