Battery thermal runaway fire extinguishing system and vehicle

Abstract

The utility model discloses a battery thermal runaway fire extinguishing system and a car, wherein a battery module is installed in a battery box, a gas sensor and a pressure sensor are arranged in the box, the gas sensor and the pressure sensor are connected and output sensing signals to a fire extinguishing control system, the fire extinguishing control system is connected and outputs control signals to a solenoid valve, the solenoid valve is installed on a high-pressure gas pipe connecting a high-pressure gas storage tank and a gas nozzle, and the gas nozzle is located in the battery box. The utility model can spray liquid nitrogen into the battery box with thermal runaway to continuously dilute the concentration of combustible gas and O2, reduce the battery temperature, and can stably and efficiently solve the thermal runaway problem.

Description

Technical Field

[0001] The utility model relates to the technical field of battery safety, and particularly to a thermal runaway fire extinguishing system for a power battery. Background Art

[0002] The power battery system is the energy storage device and power source of new energy vehicles, and is the most important component of the power system. With the development of new energy vehicles, the market share of new energy vehicles is increasing, and they are playing an increasingly important role in social and economic development.

[0003] At the same time, in recent years, there have been more and more safety accidents involving new energy vehicles, especially fire accidents involving new energy vehicles, which have a huge impact on the safety of people's lives and property. Therefore, it is extremely important to ensure the safety of the power battery system.

[0004] Therefore, many cars are currently equipped with thermal runaway fire extinguishing systems. For example, the public document with publication number CN112721736A, publication date 2021-04-30, and patent name "An integrated power battery thermal management system with cooling and fire extinguishing functions" discloses an integrated power battery thermal management system with cooling and fire extinguishing functions. The compressor, condenser, drying filter, refrigeration solenoid valve, capillary tube, and evaporator are connected in sequence to form a compressor unit refrigeration unit; a manual valve and a liquid spray solenoid valve are led out in front of the refrigeration solenoid valve to form a spray branch; a manual valve and a thermal solenoid valve are led out on the pipeline between the compressor and the condenser to form a thermal bypass branch; the first three-way connecting valve, the water absorption filter, and the regulating valve are connected to the liquid outlet of the liquid cooling plate in the battery liquid tank to form a liquid cooling branch, and the second three-way connecting valve, the water absorption filter and the liquid return solenoid valve are connected to the liquid return port of the sealed battery liquid tank to form a liquid fire extinguishing branch, and the circulating pump, temperature sensor, flow sensor, flow regulating valve, diaphragm valve and heater are connected in sequence to form a liquid cooling circulation unit.

[0005] When a power battery system experiences thermal runaway, it will generate a large amount of high-temperature solid and liquid ejecta and high-temperature and high-pressure combustible gases (the main components of the gases are CO, H2, CH4, C2H4 and C3H6, among which CO and H2 have the highest content), accompanied by violent combustion. These high-temperature and high-pressure combustible gases and flames can be ejected to the outside of the battery system through the explosion-proof valve, vent valve, and connectors of the battery system, causing personal injury and property loss. Therefore, similar systems are not ideal in terms of how to reduce the gas temperature inside the battery box, dilute the combustible gas, and block the flame, and it is difficult to reliably solve the problem of thermal runaway of the power battery system. Summary of the invention

[0006] The technical problem to be solved by the utility model is to realize a fire extinguishing system which is connected and used in coordination with various controllers, sensors and actuators to stably and efficiently quickly cool down and extinguish the high-temperature and high-pressure combustible gas and flame inside the battery pack.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a battery thermal runaway fire extinguishing system, the battery module is installed in a battery box, and a gas sensor and a pressure sensor are provided in the box. The gas sensor and the pressure sensor are connected and output the sensing signal to the fire extinguishing control system, and the fire extinguishing control system is connected and outputs the control signal to the solenoid valve. The solenoid valve is installed on a high-pressure gas pipe connecting the high-pressure gas storage tank and the gas nozzle, and the gas nozzle is located in the battery box.

[0008] The high-pressure gas storage tank stores high-pressure liquid nitrogen.

[0009] The capacity of the high-pressure gas storage tank is greater than 1L.

[0010] The gas nozzle is installed above the battery module, with the spray direction downward.

[0011] The battery box is provided with an explosion-proof valve connecting the inside and outside of the box, the opening pressure of the explosion-proof valve is 2-4 kPa, and the air permeability is ≥650 ml / min@1.5 kPa.

[0012] The battery module is equipped with a battery management system, and the battery management system communicates with the fire extinguishing control system via a CAN signal line.

[0013] The fire extinguishing control system is installed outside the battery box, and the battery management system is installed inside the box.

[0014] The fire extinguishing control system is powered separately by a separate 12V power supply.

[0015] The gas sensor is used to detect the gas concentrations of CO, H2, CH4, C2H4 and C3H6.

[0016] A car is provided with a power battery, and the power battery is provided with the battery thermal runaway fire extinguishing system.

[0017] The utility model can spray liquid nitrogen into the battery box with thermal runaway to continuously dilute the concentration of combustible gas and O2, reduce the battery temperature, and solve the thermal runaway problem stably and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following is a brief description of the contents expressed in each figure in the utility model specification and the marks in the figure:

[0019] Figure 1This is the schematic diagram of the battery thermal runaway fire extinguishing system;

[0020] The dotted line in the figure is the signal transmission path;

[0021] The marks in the above figures are: 1. Battery box; 2. Explosion-proof valve; 3. High-pressure gas storage tank; 4. Solenoid valve; 5. High-pressure gas pipe; 6. Gas nozzle; 7. Fire extinguishing control system; 8. Battery management system; 9. Gas sensor; 10. Pressure sensor; 11. Battery module. DETAILED DESCRIPTION

[0022] The following is a further detailed description of the specific implementation methods of the present invention, such as the shapes and structures of the components involved, the relative positions and connection relationships between the components, the functions and working principles of the components, the manufacturing process and the operation and use methods, etc., through the description of the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0023] like Figure 1 As shown, the power battery thermal runaway fire extinguishing system includes: a battery box 1, an explosion-proof valve 2, a high-pressure gas storage tank 3 (containing liquid nitrogen), a solenoid valve 4, a high-pressure gas pipe 5, a gas nozzle 6, a fire extinguishing control system 7, a battery management system 8, a gas sensor 9, and a pressure sensor 10; the system can be applied to new energy vehicles, such as pure electric vehicles, hybrid vehicles, and extended-range vehicles.

[0024] The battery box 1 is provided with an explosion-proof valve 2, which meets the protection level of IP68 and can control the pressure inside the battery box 1 within a certain range. The explosion-proof valve 2 is a metal spring explosion-proof valve 2, and its main function is to maintain the pressure inside the battery box 1 and the external environment. The opening pressure of the explosion-proof valve 2 is 2-4kPa, and the air permeability is ≥650ml / min@1.5kPa, so as to prevent the internal pressure of the battery box 1 from being too high and causing explosion.

[0025] The high-pressure gas storage tank 3 is connected to the solenoid valve 4 and the gas nozzle 6 through the high-pressure gas pipe 5, and is connected to the battery box 1. The high-pressure gas storage tank 3 is filled with liquid nitrogen. The solenoid valve 4 can control the on-off of the pipeline system, and the pipeline is normally closed under normal conditions;

[0026] The battery box 1 is used to install and fix the battery module 11. In this embodiment, there are 6 battery modules 11, which are evenly and symmetrically arranged and connected in sequence through high-voltage copper bars. A temperature collection point and a battery voltage collection point are provided inside the battery module 11. The temperature collection points and the battery voltage collection points in the 6 battery modules 11 are connected to the battery management system 8 (BMS) through a low-voltage wiring harness. The battery management system 8 (BMS) collects the temperature and voltage information of each battery module 11 in real time;

[0027] The battery management system 8 (BMS) collects information such as temperature, voltage, insulation resistance, etc. of each battery module 11 in real time, and determines in real time whether the battery has thermal runaway. The specific determination method can be set according to the battery properties. For example, the thermal runaway determination method adopts a conditional triggering method, and the triggering determination condition is:

[0028] a) The trigger object generates a voltage drop, and the drop value exceeds 25% of the initial voltage;

[0029] b) The maximum operating temperature of the monitoring point is 60℃;

[0030] c) The temperature rise rate dT / dt at the monitoring point is ≥1℃ / s and lasts for more than 3s.

[0031] When a) and c) or b) and c) occur, it is determined that thermal runaway occurs.

[0032] The battery management system 8 (BMS), the gas sensor 9, and the pressure sensor 10 are installed in the battery box 1; when the battery management system 8 (BMS) is working, it can always detect the battery temperature and voltage, monitor whether the battery is in a safe state, and can feedback the danger information to the owner when the battery has thermal runaway, so that the owner can escape and call the police in time to prevent the loss of life and property;

[0033] Among them, the gas sensor 9 is a gas sensor 9 for five kinds of gases, namely, CO, H2, CH4, C2H4 and C3H6. When it is detected that the gas concentration inside the battery box 1 reaches a threshold value, an alarm signal is sent to the fire extinguishing control system 7; the pressure sensor 10 monitors the internal pressure of the battery box 1 at all times, and uploads the internal pressure of the battery box 1 to the fire extinguishing control system 7 in real time;

[0034] The fire extinguishing control system 7 is connected to the battery management system 8 (BMS), the gas sensor 9, the pressure sensor 10, and the solenoid valve 4 through the CAN signal line, and the signals are constantly exchanged to monitor the battery status; the fire extinguishing control system 7 is arranged outside the power battery box 1, and is powered separately by a separate 12V power supply to prevent the fire extinguishing control system 7 from being damaged and failing due to flames and high temperatures caused by thermal runaway. The fire extinguishing control system 7 is connected to the battery management system 8 (BMS), the gas sensor 9, the pressure sensor 10, and the solenoid valve 4 inside the power battery box 1 through the CAN signal line, and the signals are constantly exchanged to monitor the battery status;

[0035] The high-pressure gas storage tank 3 is connected to the solenoid valve 4 and the gas nozzle 6 through the high-pressure gas pipe 5; 1L of liquid nitrogen is filled in the high-pressure gas storage tank 3, and the solenoid valve 4 controls the on-off of the pipeline system by receiving the signal of the fire extinguishing control system 7, and the pipeline is normally closed;

[0036] The specific working principle of the system is as follows: when the battery management system 8 (BMS) detects that the battery has thermal runaway, it will transmit the thermal runaway signal to the fire extinguishing control system 7. The fire extinguishing control system 7 controls and adjusts the solenoid valve 4 at all times according to the signals transmitted by the battery management system 8 (BMS), the gas sensor 9, and the pressure sensor 10, thereby controlling the ejection of liquid nitrogen in the high-pressure gas storage tank 3. When the internal pressure of the battery box 1 reaches the threshold set by the pressure sensor 10, the pressure sensor 10 transmits the signal to the fire extinguishing control system 7, and the fire extinguishing control system 7 controls the solenoid valve 4 to close. At this time, the liquid nitrogen sprayed into the battery box 1 quickly absorbs heat and vaporizes, and starts to fill the battery box 1 from the bottom up. The internal space of the battery box 1 is filled, and the O2 inside the battery box 1 is cooled and diluted with the concentration of high-temperature and high-pressure gas. When the internal pressure of the battery box 1 reaches the opening threshold of the explosion-proof valve 2, the explosion-proof valve 2 opens, and the gas inside the battery box 1 is quickly ejected. The concentration of combustible gas and O2 in the battery box 1 is reduced, and the explosion-proof valve 2 is closed. At this time, the fire extinguishing control system 7 controls the solenoid valve 4 to open again, and liquid nitrogen is sprayed into the battery box 1 again, continuously diluting the concentration of combustible gas and O2 and reducing the battery temperature. When the battery temperature is lower than the thermal runaway threshold and the gas concentration is lower than the threshold, the fire extinguishing control system 7 closes the solenoid valve 4, stops fire extinguishing, and the battery management system 8 (BMS) switches to real-time monitoring mode.

[0037] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A battery thermal runaway fire extinguishing system, characterized in that: The battery module is installed in a battery box, and a gas sensor and a pressure sensor are arranged in the box. The gas sensor and the pressure sensor are connected to and output sensing signals to a fire extinguishing control system, and the fire extinguishing control system is connected to and outputs control signals to a solenoid valve. The solenoid valve is installed on a high-pressure gas pipe connecting a high-pressure gas storage tank and a gas nozzle, and the gas nozzle is located in the battery box; The high-pressure gas storage tank stores high-pressure liquid nitrogen.

2. The battery thermal runaway fire extinguishing system according to claim 1, characterized in that: The capacity of the high-pressure gas storage tank is greater than 1L.

3. The battery thermal runaway fire extinguishing system according to claim 2, characterized in that: The gas nozzle is installed above the battery module, with the spray direction downward.

4. The battery thermal runaway fire extinguishing system according to claim 3, characterized in that: The battery box is provided with an explosion-proof valve connecting the inside and outside of the box, the opening pressure of the explosion-proof valve is 2-4 kPa, and the air permeability is ≥650 ml / min@1.5 kPa.

5. The battery thermal runaway fire extinguishing system according to any one of claims 1 to 4, characterized in that: The battery module is equipped with a battery management system, and the battery management system communicates with the fire extinguishing control system via a CAN signal line.

6. The battery thermal runaway fire extinguishing system according to claim 5, characterized in that: The fire extinguishing control system is installed outside the battery box, and the battery management system is installed inside the box.

7. The battery thermal runaway fire extinguishing system according to claim 6, characterized in that: The fire extinguishing control system is powered separately by a separate 12V power supply.

8. The battery thermal runaway fire extinguishing system according to claim 7, characterized in that: The gas sensor is used to detect the gas concentrations of CO, H2, CH4, C2H4 and C3H6.

9. A car, wherein a power battery is provided inside the car, characterized in that: The power battery is provided with a battery thermal runaway fire extinguishing system as described in any one of claims 1-8.

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