Power battery safety monitoring method

Abstract

The invention provides a power battery safety monitoring method. The method comprises the steps that a control module receives the state, sent by a first sensor, of an anti-explosion valve and the state value, sent by a second sensor, of gas in a battery pack; the control module compares the state value of the gas in the battery pack with a preset gas state threshold value; and in response to the received state of the explosion-proof valve and the comparison result of the state value of the gas in the battery pack and the gas state threshold value, the control module sends a corresponding alarm signal to the BMS. The method has the advantages that the first sensor and the second sensor are combined for simultaneous detection, the missing detection risk generated when a single sensor is adopted can be prevented, frequent occurrence of false alarms can be prevented, the reliability of the detection result is high, the safety state of the power battery can be comprehensively, stably and reliably monitored, and the safety of the power battery is effectively improved. And faults such as blockage, corrosion and damage of the anti-explosion valve can be recognized, a user is reminded, risk prevention and control are enhanced, and the use safety of the vehicle is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive power batteries, and in particular to a power battery safety monitoring method. Background Art

[0002] The explosion-proof valve of new energy vehicles is used to protect the safety of batteries during thermal runaway and prevent the battery shell from exploding. Currently, the industry uses a single displacement sensor, pressure sensor, smoke sensor or gas composition sensor to identify thermal runaway signals. However, the use of a single sensor may produce false alarms or missed alarms, posing a safety hazard. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a power battery safety monitoring method, which uses a first sensor and a second sensor to simultaneously monitor the status of the explosion-proof valve and the gas status in the battery pack, and sends a corresponding alarm signal to the BMS based on the monitoring situation.

[0004] The present invention solves the technical problem by adopting the following technical solutions:

[0005] A power battery safety monitoring method is performed by a safety monitoring system. The safety monitoring system includes a control module, a first sensor for detecting the state of an explosion-proof valve, and a second sensor for detecting the state of gas in a battery pack. The first sensor and the second sensor are both electrically connected to the control module. The control module is electrically connected to a battery management system (BMS).

[0006] The method comprises the following steps:

[0007] Step 1: The control module receives the state of the explosion-proof valve sent by the first sensor and the state value of the gas in the battery pack sent by the second sensor;

[0008] Step 2: The control module compares the state value of the gas in the battery pack with a preset gas state threshold;

[0009] Step 3: In response to the received explosion-proof valve status and the comparison result of the gas status value in the battery pack with the gas status threshold, the control module sends an alarm signal to the BMS:

[0010] When the gas state value is greater than or equal to the gas state threshold and the explosion-proof valve is in the open state, the control module sends a high-risk alarm signal to the BMS;

[0011] When the gas state value is greater than or equal to the gas state threshold and the explosion-proof valve is in the closed state, the control module sends a medium-risk alarm signal to the BMS;

[0012] When the gas state value is less than the gas state threshold and the explosion-proof valve is in the open state, the control module sends a low-risk alarm signal to the BMS;

[0013] When the gas state value is less than the gas state threshold and the explosion-proof valve is in a closed state, the control module filters the signals collected by the first sensor and the second sensor.

[0014] Furthermore, the method further includes: the BMS receives a vehicle status signal, the vehicle status signal includes a driving state and a stopped state, and the stopped state includes a parked non-working state and a parked charging state.

[0015] Furthermore, the method further comprises the following steps:

[0016] When the alarm signal sent by the control module received by the BMS is a high-risk alarm signal, the BMS directly sends a power system abnormality signal to the VCU; when the alarm signal sent by the control module received by the BMS is a medium-risk alarm signal, or the alarm signal sent by the control module received by the BMS is a low-risk alarm signal, and the vehicle status signal received by the BMS is in a stopped state, the BMS identifies the battery status and sends a power system abnormality signal to the VCU; when the alarm signal sent by the control module received by the BMS is a low-risk alarm signal, and the vehicle status signal received by the BMS is in a driving state, the BMS filters the low-risk alarm signal.

[0017] Furthermore, the method further comprises the following steps:

[0018] When the alarm signal sent by the control module received by the BMS is a high-risk alarm signal, or the alarm signal sent by the control module received by the BMS is a medium-risk alarm signal or a low-risk alarm signal, and the battery status is identified as abnormal:

[0019] When the vehicle status signal received by the BMS indicates that the vehicle is in driving state, the VCU controls the on-board computer to record abnormal information of the power system, and controls the instrument panel to display the power battery safety alarm information, reminding the user to leave the vehicle, and upload it to the new energy vehicle alarm system;

[0020] When the vehicle status signal received by the BMS indicates that the vehicle is stopped, the VCU controls the onboard computer to record abnormal information of the power system and push the power battery safety alarm information to the user, reminding the user to notify people near the vehicle to keep a safe distance and upload it to the new energy vehicle alarm system;

[0021] When the alarm signal sent by the control module received by the BMS is a medium-risk alarm signal or a low-risk alarm signal, and the battery status is normal:

[0022] When the vehicle status signal received by the BMS indicates that the vehicle is in driving state, the VCU controls the on-board computer to record abnormal information of the power system and controls the instrument panel to display abnormal information of the power system to remind the user to check;

[0023] When the vehicle status signal received by the BMS is that the vehicle is in a stopped state, the VCU controls the on-board computer to record the abnormal power system information and push the abnormal power system information to the user to remind the user to check.

[0024] Furthermore, the method further includes: the control module receiving a status signal of the BMS; when the BMS is in an activated state, the control module directly sends an alarm signal to the BMS; when the BMS is in a dormant state, the control module activates the BMS and sends an alarm signal to the BMS, so that the control module and the BMS can communicate in a timely manner.

[0025] Furthermore, the control module periodically receives the status of the explosion-proof valve sent by the first sensor and the status value of the gas in the battery pack sent by the second sensor. When the BMS is in the activated state, the receiving period of the control module is 0.1-0.5s. When the BMS is in the dormant state, the receiving period of the control module is 1-5s. The collection period can be set according to the risk level to monitor the safety status of the power battery in a timely manner.

[0026] Furthermore, the first sensor is an on-off sensor, which detects the open and closed state of the explosion-proof valve through an on-off signal, and the detection is simple.

[0027] Furthermore, the first sensor is a displacement sensor, which is used to detect the opening displacement value of the explosion-proof valve. The control module compares the opening displacement value of the explosion-proof valve with a preset opening threshold value. When the opening displacement value of the explosion-proof valve is greater than or equal to the opening threshold value, the explosion-proof valve is in an open state; preferably, the opening threshold value of the explosion-proof valve is 10%-20% of the maximum displacement when the explosion-proof valve is fully opened.

[0028] Furthermore, the second sensor is a pressure sensor, and the gas state value and the gas state threshold are the gas pressure change rate; preferably, the gas state threshold is one of 0.8-1.2 kPa / s.

[0029] Furthermore, the second sensor is a gas composition sensor, and the gas state value and gas state threshold are the gas concentration change rate; preferably, the second sensor is a carbon monoxide sensor, and the gas state threshold is one of 2000-5000ppm / s.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) Combining the first sensor and the second sensor for simultaneous detection can prevent the risk of missed detection when using a single sensor and can prevent frequent false alarms. The reliability of the detection results is higher than that of a single sensor solution, and can comprehensively, stably and reliably monitor the safety status of the power battery, effectively improving the safety of the power battery.

[0032] (2) By combining the first sensor and the second sensor for simultaneous detection, it is possible to identify faults such as blockage, rust, and damage of the explosion-proof valve, and to remind the user, thereby strengthening risk prevention and control and improving vehicle safety.

[0033] (3) Based on the comparison results of the status of the explosion-proof valve and the status value of the gas in the battery pack with the gas status threshold, the control module sends an alarm signal of the corresponding risk level to the BMS; when the alarm signal received by the BMS is a high-risk alarm signal, the BMS directly sends a power system abnormality signal to the VCU, reducing the alarm response time and making the VCU issue an alarm warning more timely, allowing users to leave the vehicle faster and stay away from danger, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a block diagram of the safety monitoring system of the present invention.

[0035] Figure 2 Schematic diagram of the logic relationship of the power battery safety monitoring method of the present invention.

[0036] In the figure: 100 - control module; 200 - first sensor; 300 - second sensor; 400 - BMS; 500 - VCU. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0038] In the description of the present invention, it should be noted that the terms “first” and “second” are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0039] The present invention provides a power battery safety monitoring method, which is executed by a safety monitoring system. Figure 1As shown, the safety monitoring system includes a control module 100, a first sensor 200 and a second sensor 300. The first sensor 200 is used to detect the status of the explosion-proof valve, and the second sensor 300 is used to detect the gas status in the battery pack; the first sensor 200 and the second sensor 300 are both electrically connected to the control module 100; the control module 100 is electrically connected to the BMS400, and the control module 100 can be set separately in the battery pack or integrated in the BMS400 (Battery Management System).

[0040] refer to Figure 2 As shown, the method includes the following steps:

[0041] Step 1: The control module 100 receives the status of the explosion-proof valve sent by the first sensor 200 and the status value of the gas in the battery pack sent by the second sensor 300;

[0042] Step 2: The control module 100 compares the gas state value in the battery pack with a preset gas state threshold;

[0043] Step 3: In response to the received explosion-proof valve status and the comparison result of the gas status value in the battery pack with the gas status threshold, the control module 100 sends an alarm signal to the BMS 400:

[0044] When the gas state value is greater than or equal to the gas state threshold and the explosion-proof valve is in the open state, the control module 100 sends a high-risk alarm signal to the BMS 400;

[0045] When the gas state value is greater than or equal to the gas state threshold and the explosion-proof valve is in the closed state, the control module 100 sends a medium-risk alarm signal to the BMS 400;

[0046] When the gas state value is less than the gas state threshold and the explosion-proof valve is in the open state, the control module 100 sends a low-risk alarm signal to the BMS 400;

[0047] When the gas state value is less than the gas state threshold and the explosion-proof valve is in a closed state, the control module 100 filters the signals collected by the first sensor 200 and the second sensor 300 .

[0048] When a power battery experiences thermal runaway, reactions within the battery pack produce various gases, such as carbon monoxide and hydrogen. Simultaneously, the gas state within the battery pack changes, forming high-temperature, high-pressure gases. The gas pressure within the battery pack causes the explosion-proof valve to open, venting gas to the exterior of the battery pack and preventing the battery casing from exploding. When the gas state value exceeds the gas state threshold and the explosion-proof valve is open, the signal collected by the second sensor 300 indicates a change in the gas state within the battery pack, while the signal collected by the first sensor 200 indicates that the explosion-proof valve is operating normally to discharge high-temperature, high-pressure gases. At this point, the control module 100, based on the changes in the gas state within the battery pack and the opening status of the explosion-proof valve, can directly determine that the power battery has experienced thermal runaway and that the risk level is high. The control module 100 then sends a high-risk alarm signal to the BMS 400.

[0049] When the gas state value is greater than or equal to the gas state threshold and the explosion-proof valve is in the closed state, the signal collected by the second sensor 300 indicates a change in the gas state within the battery pack, but the signal collected by the first sensor 200 indicates the explosion-proof valve is closed and not open. In this case, the change in gas state within the battery pack could be due to thermal runaway of the power battery, but the explosion-proof valve is blocked, corroded, or otherwise unable to open properly. Alternatively, it could be due to external smoke or gas diffusing into the battery pack, or gas generated by leaking cells, causing the gas state within the battery pack to change, but the valve's opening pressure has not been reached, preventing the valve from opening. Therefore, the control module 100 cannot directly determine whether the power battery has experienced thermal runaway based solely on the gas state change within the battery pack. The risk level is medium, and the control module 100 sends a medium risk alarm signal to the BMS 400. If the first sensor 200 alone were used to detect the explosion-proof valve's state, it would fail to identify failures such as blockage or corrosion, resulting in missed detection and the risk of failing to trigger an alarm.

[0050] When the gas state value is less than the gas state threshold and the explosion-proof valve is open, the signal collected by the second sensor 300 indicates that the gas state within the battery pack has not changed, but the signal collected by the first sensor 200 indicates that the explosion-proof valve is open. In this case, the power battery may be experiencing thermal runaway. The gas pressure within the battery pack is causing the explosion-proof valve to open, but the second sensor 300 may be malfunctioning, or the second sensor 300 is positioned so that it cannot detect changes in the gas state. Alternatively, the explosion-proof valve may have opened erroneously due to vibration or damage. Therefore, the control module 100 cannot directly determine whether the power battery has experienced thermal runaway based solely on the opening state of the explosion-proof valve. The risk level is low, and the control module 100 sends a low-risk alarm signal to the BMS 400. If the second sensor 300 is used alone to detect the gas state within the battery pack, this condition cannot be detected, and damage to the explosion-proof valve cannot be identified. A malfunction of the second sensor 300 creates the risk of failing to trigger an alarm.

[0051] When the gas state value is less than the gas state threshold and the explosion-proof valve is in the closed state, it indicates that the power battery is operating normally and no risk occurs. The control module 100 filters the signals collected by the first sensor 200 and the second sensor 300.

[0052] The method further includes: the BMS 400 receiving a vehicle status signal, the vehicle status signal including a driving state and a stopped state, and the stopped state including a parked non-operating state and a parked charging state.

[0053] When the control module 100 sends a medium-risk alarm signal or a low-risk alarm signal to the BMS400, the BMS400 needs to identify the battery status in combination with the vehicle status signal, and comprehensively judge whether the battery has experienced thermal runaway through the battery voltage, current, temperature and other status signals, and in combination with the received vehicle status signal, and accordingly send a power system abnormality signal to the VCU500 (Vehicle Control Unit) or filter the low-risk alarm signal. Specifically, the method further includes the following steps:

[0054] When the alarm signal sent by the control module 100 received by the BMS 400 is a high-risk alarm signal, the BMS 400 directly sends a power system abnormality signal to the VCU 500, reducing the alarm response time and enabling the VCU 500 to issue an alarm warning more promptly, allowing the user to leave the vehicle faster and stay away from danger, thereby improving safety;

[0055] When the alarm signal sent by the control module 100 received by the BMS 400 is a medium-risk alarm signal, or the alarm signal sent by the control module 100 received by the BMS 400 is a low-risk alarm signal, and the vehicle status signal received by the BMS 400 indicates that the vehicle is in a stopped state, the BMS 400 identifies the battery status and sends a power system abnormality signal to the VCU 500;

[0056] If the alarm signal received by the BMS 400 from the control module 100 is a low-risk alarm signal and the vehicle status signal received by the BMS 400 indicates the vehicle is in motion, the BMS 400 will filter the low-risk alarm signal. In this case, the gas state value is less than the gas state threshold, and the explosion-proof valve is in the open state. This is mostly due to a small amount of displacement caused by vibration and turbulence during vehicle driving, which can lead to false opening. By filtering the low-risk alarm signal, the BMS 400 can prevent frequent false alarms and reduce the number of false alarms.

[0057] When the alarm signal sent by the control module 100 received by the BMS 400 is a high-risk alarm signal or a medium-risk alarm signal, the vehicle is in a driving state or a stopped state. When the alarm signal sent by the control module 100 received by the BMS 400 is a low-risk alarm signal, the vehicle is in a stopped state. Based on the battery status and the vehicle status, the VCU 500 takes corresponding warning measures. Specifically, the method further includes the following steps:

[0058] If the BMS 400 receives a high-risk alarm signal from the control module 100, or a medium-risk or low-risk alarm signal, and detects an abnormal battery status, this indicates thermal runaway of the power battery, and the VCU 500 must promptly issue a warning. Specifically, when the BMS 400 receives a vehicle status signal indicating the vehicle is in motion, the VCU 500 controls the onboard computer to record the powertrain anomaly information and displays a power battery safety warning message on the instrument panel, prompting the user to exit the vehicle and uploading the information to the new energy vehicle alarm system. For example, the VCU 500 can display "Power battery safety warning, please exit the vehicle immediately" on the instrument panel, and simultaneously add a flashing warning light and voice notification to alert the user, ensuring they receive a timely warning and take evasive action. If the BMS 400 receives a vehicle status signal indicating the vehicle is stopped, the VCU 500 controls the onboard computer to record the powertrain anomaly information and push the power battery safety warning message to the user, prompting them to notify those near the vehicle to maintain a safe distance and uploading the information to the new energy vehicle alarm system. For example, VCU500 can control the background to push reminders to users through mobile phone apps and text messages: "Power battery safety alarm, please notify people near the vehicle as soon as possible to keep a safe distance."

[0059] If the BMS400 receives a medium-risk or low-risk alarm signal from the control module 100 and detects no abnormalities in the battery status, this indicates that the power battery has not experienced thermal runaway, but a powertrain failure has occurred, posing a safety hazard. The VCU500 must promptly issue an inspection reminder. Specifically, when the BMS400 receives a vehicle status signal indicating the vehicle is in motion, the VCU500 controls the on-board computer to record the powertrain abnormality information and displays it on the instrument panel, prompting the user to perform an inspection. For example, the VCU500 might display "Powertrain abnormality, stop for inspection recommended" on the instrument panel and flash a warning light. When the BMS400 receives a vehicle status signal indicating the vehicle is stopped, the VCU500 controls the on-board computer to record the powertrain abnormality information and push it to the user, prompting them to perform an inspection. For example, the VCU500 might control the backend to push a "Powertrain abnormality, stop for inspection recommended" reminder to the user via a mobile app and text message.

[0060] When the alarm signal sent by the control module 100 received by the BMS400 is a medium-risk alarm signal, the gas state value is greater than or equal to the gas state threshold, the second sensor 300 detects a change in the gas state in the battery pack, the first sensor 200 detects that the explosion-proof valve is in the closed state, and the BMS400 monitors that the battery status is normal, the change in the gas state in the battery pack may be due to damage to the waterproof and breathable membrane of the explosion-proof valve, the diffusion of external smoke and gas into the battery pack, or gas generated by battery cell leakage. After being reminded, the user can promptly inspect and replace the explosion-proof valve and power battery to eliminate safety hazards and avoid danger during continued use.

[0061] When the alarm signal sent by the control module 100 and received by the BMS400 is a low-risk alarm signal, the vehicle is stopped, the gas state value is less than the gas state threshold, the second sensor 300 detects that the gas state in the battery pack has not changed, the first sensor 200 detects that the explosion-proof valve is open, and the BMS400 monitors that the battery status is normal, the explosion-proof valve may be damaged and accidentally opened. After being reminded, the user can promptly inspect and replace the explosion-proof valve to avoid water entering the battery pack through the damaged explosion-proof valve when the vehicle is wading, which may pose a safety risk.

[0062] The combined use of the first sensor 200 and the second sensor 300 for simultaneous detection can prevent the risk of missed detections and frequent false alarms that can occur when using a single sensor. The reliability of the detection results is higher than that of a single sensor solution, enabling comprehensive, stable, and reliable monitoring of the safety status of the power battery, effectively improving power battery safety. It can also identify faults such as explosion-proof valve blockage, rust, and damage, and alert the user, strengthening risk prevention and control, and improving vehicle safety.

[0063] To ensure timely communication between the control module 100 and the BMS 400, the method further includes: the control module 100 receiving a status signal from the BMS 400. When the BMS 400 is in an active state, the control module 100 directly sends an alarm signal to the BMS 400; when the BMS 400 is in a dormant state, the control module 100 activates the BMS 400 and sends an alarm signal to the BMS 400. When the vehicle is in a driving state or a parked charging state, the BMS 400 is in an active state, and the control module 100 can directly send an alarm signal to the BMS 400 to report the alarm information; when the vehicle is parked and not in operation, the BMS 400 is in a dormant state, and the control module 100 sends an alarm signal to the BMS 400 to wake up the BMS 400 and simultaneously report the alarm information.

[0064] The first sensor 200 and the second sensor 300 periodically collect data and send it to the control module 100. Accordingly, the control module 100 periodically receives information on the status of the explosion-proof valve from the first sensor 200 and the status of the gas in the battery pack from the second sensor 300. The collection period can be set based on the risk level. When the BMS 400 is activated, the vehicle is in the driving state or the parked charging state, and the power battery is in operation. At this time, the risk level is high, and timely monitoring of the power battery's safety status is required. The control module 100's receiving period can be set to 0.1-0.5 seconds. For example, the first sensor 200 and the second sensor 300 can send a signal to the control module 100 every 0.1 second, 0.2 second, 0.3 second, 0.4 second, or 0.5 second. When the BMS400 is in the dormant state, the vehicle is parked and not working. Accordingly, the power battery is not working. At this time, the risk level is low. The receiving period of the control module 100 can be set to 1-5s. For example, the first sensor 200 and the second sensor 300 can send a signal to the control module 100 every 1s, 2s, 3s, 4s or 5s.

[0065] In one embodiment of the present invention, the first sensor 200 is configured as an on-off sensor. The on-off signal generated by the first sensor 200 can thereby detect the open / closed state of the explosion-proof valve, resulting in simple detection and low cost. For example, the first sensor 200 can be configured as a displacement sensor. When the explosion-proof valve is opened, displacement is generated, which can trigger the displacement sensor to generate an on-off signal. Preferably, the first sensor 200 can also be configured as a circuit switch, for example, where the on / off signal is generated by the closing and opening of the circuit switch.

[0066] When the first sensor 200 is a displacement sensor, the displacement sensor can also detect the opening displacement value of the explosion-proof valve. The control module 100 compares the opening displacement value of the explosion-proof valve with a preset opening threshold. When the opening displacement value of the explosion-proof valve is greater than or equal to the opening threshold, it indicates that the explosion-proof valve is in the open state, and the detection is accurate. Preferably, the opening threshold of the explosion-proof valve is 10%-20% of the maximum displacement of the explosion-proof valve when fully open. The maximum displacement of the explosion-proof valve when fully open varies depending on the model of the explosion-proof valve. The maximum displacement of the explosion-proof valve when fully open can be determined through vibration and collision testing of the explosion-proof valve.

[0067] In one embodiment of the present invention, the second sensor 300 is configured as a pressure sensor, and the gas state value and the gas state threshold are the gas pressure change rate. Preferably, the gas state threshold is one of 0.8-1.2 kPa / s. For example, the gas state threshold is the gas pressure change rate threshold, which can be set to 0.8 kPa / s, 0.9 kPa / s, 1.0 kPa / s, 1.1 kPa / s, 1.2 kPa / s, etc. When the gas pressure change rate collected by the second sensor 300 is greater than or equal to the gas pressure change rate threshold, it indicates that the gas state in the battery pack has changed.

[0068] In one embodiment of the present invention, the second sensor 300 is configured as a gas composition sensor, and the state value of the gas and the gas state threshold are the gas concentration change rate. For example, the second sensor 300 can use a carbon monoxide sensor, and the gas state threshold is one of 2000-5000ppm / s. For example, the gas state threshold is a gas concentration change rate threshold, which can be set to 2000ppm / s, 3000ppm / s, 4000ppm / s, 5000ppm / s, etc. When the gas concentration change rate collected by the second sensor 300 is ≥ the gas concentration change rate threshold, it indicates that the gas state in the battery pack has changed. When a power battery undergoes thermal runaway, the battery reaction will also produce nitrogen, carbon dioxide, hydrogen, etc. The second sensor 300 can also use a nitrogen sensor, a carbon dioxide sensor, a hydrogen sensor, etc. Accordingly, the gas concentration change rate can be set separately according to each gas component.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A power battery safety monitoring method, characterized in that: The method is performed by a safety monitoring system, which includes a control module, a first sensor and a second sensor, wherein the first sensor is used to detect the state of the explosion-proof valve, and the second sensor is used to detect the state of the gas in the battery pack; the first sensor and the second sensor are both electrically connected to the control module; and the control module is electrically connected to the BMS; The method comprises the following steps: Step 1, the control module receives the state of the explosion-proof valve sent by the first sensor and the state value of the gas in the battery pack sent by the second sensor; Step 2: The control module compares the state value of the gas in the battery pack with a preset gas state threshold; Step 3: In response to the received explosion-proof valve status and the comparison result between the status value of the gas in the battery pack and the gas status threshold, the control module sends an alarm signal to the BMS: When the gas state value is ≥ the gas state threshold and the explosion-proof valve is in the open state, the control module sends a high-risk alarm signal to the BMS; When the gas state value is ≥ the gas state threshold and the explosion-proof valve is in the closed state, the control module sends a medium-risk alarm signal to the BMS; When the gas state value is less than the gas state threshold and the explosion-proof valve is in the open state, the control module sends a low-risk alarm signal to the BMS; When the gas state value is less than the gas state threshold and the explosion-proof valve is in a closed state, the control module filters the signals collected by the first sensor and the second sensor.

2. The power battery safety monitoring method according to claim 1, characterized in that: The method further includes: the BMS receives a vehicle status signal, the vehicle status signal includes a driving state and a stop state, and the stop state includes a parking non-operating state and a parking charging state.

3. The power battery safety monitoring method according to claim 2, characterized in that: The method further comprises the following steps: When the alarm signal sent by the control module received by BMS is a high-risk alarm signal, BMS directly sends a power system abnormality signal to VCU; when the alarm signal sent by the control module received by BMS is a medium-risk alarm signal, or the alarm signal sent by the control module received by BMS is a low-risk alarm signal, and the vehicle status signal received by BMS is a vehicle stopped state, BMS identifies the battery status and sends a power system abnormality signal to VCU; when the alarm signal sent by the control module received by BMS is a low-risk alarm signal, and the vehicle status signal received by BMS is a vehicle driving state, BMS filters the low-risk alarm signal.

4. The power battery safety monitoring method according to claim 3, characterized in that: The method further comprises the following steps: When the alarm signal sent by the control module received by the BMS is a high-risk alarm signal, or the alarm signal sent by the control module received by the BMS is a medium-risk alarm signal or a low-risk alarm signal, and the battery status is identified to be abnormal: When the vehicle status signal received by BMS is the vehicle driving status, VCU controls the driving computer to record the abnormal information of the power system, and controls the instrument panel to display the power battery safety alarm information, reminding the user to leave the vehicle, and upload it to the new energy vehicle alarm system; When the vehicle status signal received by BMS is the vehicle stopped state, VCU controls the driving computer to record abnormal information of the power system, and pushes the power battery safety alarm information to the user, reminding the user to notify people near the vehicle to keep a safe distance, and upload it to the new energy vehicle alarm system; When the alarm signal sent by the control module received by the BMS is a medium-risk alarm signal or a low-risk alarm signal, and the battery status is recognized to be normal: When the vehicle status signal received by the BMS is the vehicle driving status, the VCU controls the driving computer to record the abnormal information of the power system, and controls the instrument panel to display the abnormal information of the power system to remind the user to check; When the vehicle status signal received by the BMS is that the vehicle is in a stopped state, the VCU controls the on-board computer to record the abnormal power system information and push the abnormal power system information to the user to remind the user to check.

5. The power battery safety monitoring method according to claim 2, characterized in that: The method further includes: the control module receiving a status signal of the BMS, and when the BMS is in an activated state, the control module directly sending an alarm signal to the BMS; when the BMS is in a dormant state, the control module activates the BMS and sends an alarm signal to the BMS.

6. The power battery safety monitoring method according to claim 5, characterized in that: The control module periodically receives the status of the explosion-proof valve sent by the first sensor and the status value of the gas in the battery pack sent by the second sensor. When the BMS is in the activated state, the receiving period of the control module is 0.1-0.5s, and when the BMS is in the dormant state, the receiving period of the control module is 1-5s.

7. The power battery safety monitoring method according to claim 1, characterized in that: The first sensor is an on-off sensor.

8. The power battery safety monitoring method according to claim 1, characterized in that: The first sensor is a displacement sensor, which is used to detect the opening displacement value of the explosion-proof valve. The control module compares the opening displacement value of the explosion-proof valve with a preset opening threshold value. When the opening displacement value of the explosion-proof valve is ≥ the opening threshold value, the explosion-proof valve is in an open state; preferably, the opening threshold value of the explosion-proof valve is 10%-20% of the maximum displacement when the explosion-proof valve is fully opened.

9. The power battery safety monitoring method according to claim 1, characterized in that: The second sensor is a pressure sensor, and the gas state value and the gas state threshold are the gas pressure change rate; preferably, the gas state threshold is one of 0.8-1.2 kPa / s.

10. The power battery safety monitoring method according to claim 1, characterized in that: The second sensor is a gas composition sensor, and the gas state value and the gas state threshold are the gas concentration change rate; preferably, the second sensor is a carbon monoxide sensor, and the gas state threshold is one of 2000-5000ppm / s.

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