CN117937020A - A lithium-ion battery explosion-proof system and explosion-proof method for mining - Google Patents

Abstract

The invention discloses an explosion-proof system and an explosion-proof method of a mining lithium ion battery, wherein the explosion-proof system comprises an explosion-proof battery box body, a micro-channel structure, a thermal runaway abnormal signal detection device, a thermal runaway fire extinguishing device, a thermal runaway gas treatment device and a linkage control box; the thermal runaway abnormal signal detection device detects temperature, pressure and gas signals in the micro-channel structure, and sends the abnormal signals to the linkage control box after exceeding a preset threshold value, so that the thermal runaway fire extinguishing device is controlled to extinguish a fire in a thermal runaway area, and meanwhile, the thermal runaway gas treatment device is controlled to cool and recover the thermal runaway gas until the temperature, pressure and gas signals in the micro-channel structure are recovered to normal levels. The rapid cooling, depressurization, inerting and safety treatment of the thermal runaway gas are realized, the battery pack is monitored in real time, and the fire extinguishing procedure is automatically started under abnormal conditions, so that the explosion occurrence when the thermal runaway of the lithium ion battery occurs is inhibited, and the use safety of the underground lithium ion storage battery of the coal mine is improved.

Description

A lithium-ion battery explosion-proof system and explosion-proof method for mining

Technical Field

The invention relates to a lithium ion battery explosion-proof system and an explosion-proof method for mining, belonging to the technical field of mining safety.

Background technique

As the current mainstream battery power energy source, lithium-ion has broad application prospects, but its fire and explosion safety issues are particularly prominent in the harsh working environment of coal mines. During thermal runaway, lithium-ion batteries mainly release CO and _H2 , and contain a variety of gases such as alkanes, ammonia and hydrogen chloride. The gases released show a greater risk of gas explosion and combustion. During the thermal runaway process of lithium-ion batteries, accompanied by a large amount of high-temperature reactants, electrolytes and gases ejected, the high-temperature solid reactant particles have the risk of igniting combustible gases, which in turn cause combustible gas explosions. Therefore, there is an urgent need for a safety system that can automatically take protective measures when the battery is in thermal runaway.

Summary of the invention

The technical problem to be solved by the present invention is to provide an explosion-proof system and explosion-proof method for lithium-ion batteries for mining, detect abnormal signals of thermal runaway of the battery by a thermal runaway abnormal signal detection device, and carry out corresponding thermal runaway treatment measures in linkage, thereby suppressing the explosion of the lithium-ion battery when thermal runaway occurs, and improving the safety of lithium-ion batteries used in coal mines.

The present invention adopts the following technical solutions to solve the above technical problems:

A lithium-ion battery explosion-proof system for mining, the system comprising an explosion-proof battery box, a microchannel structure, a thermal runaway abnormal signal detection device, a thermal runaway fire extinguishing device, a thermal runaway gas processing device and a linkage control box; wherein the explosion-proof battery box comprises a first cavity and a second cavity connected to each other, the microchannel structure is arranged on six inner walls of the first cavity, and the microchannel structure on the inner wall at the top of the first cavity is a sunken hemispherical structure, a plurality of microchannel inlets are arranged at the hemispherical edge of the hemispherical structure and the edges of other inner wall microchannel structures, a gas collecting and guiding device is arranged at the bottom microchannel inlet of the hemispherical edge, the gas collecting and guiding device is connected to a recovery tank body through a recovery pipeline, and the recovery tank body is fixed in the linkage control box; the lithium-ion battery for mining is placed on the microchannel structure at the bottom of the first cavity; the linkage control box is arranged in the second cavity;

The thermal runaway abnormal signal detection device is connected to the linkage control box, and the thermal runaway fire extinguishing device and the thermal runaway gas processing device are respectively connected to the linkage control box; the thermal runaway abnormal signal detection device is used to detect the temperature, pressure and gas signals in the microchannel structure, and after the temperature, pressure and gas signals exceed the preset threshold value, the abnormal signals of temperature, pressure and gas are sent to the linkage control box, and the linkage control box controls the thermal runaway fire extinguishing device to extinguish the thermal runaway area, and at the same time controls the thermal runaway gas processing device to cool the thermal runaway gas and recover it into the recovery tank until the temperature, pressure and gas signals in the microchannel structure return to normal levels.

As a preferred solution of the system of the present invention, a PCM coating is coated between two adjacent microchannel inlets, and the PCM coating is prepared from an organic PCM material and an epoxy resin carrier.

As a preferred solution of the system of the present invention, the gas collecting and guiding device uses a thermosensitive memory material that is closed at low temperatures and opens when encountering hot gas, forming a one-way directional flow structure with the lowest microchannel inlet.

As a preferred solution of the system of the present invention, the thermal runaway abnormal signal detection device includes a microchannel temperature-pressure composite sensor, a thermal runaway composite gas detection device and a linkage alarm device respectively connected to a linkage control box; a plurality of microchannel temperature-pressure composite sensors are arranged around the microchannel structure of all inner walls for detecting the temperature and pressure signals in the microchannel structure; the thermal runaway composite gas detection device is arranged above the mining lithium-ion battery for detecting the gas signal in the first cavity; the linkage alarm device is used to send abnormal temperature, pressure and gas signals to the linkage control box after the temperature, pressure and gas signals exceed preset thresholds, and the linkage alarm device is fixed in the linkage control box.

As a preferred solution of the system of the present invention, the thermal runaway fire extinguishing device includes a fire extinguishing tank body, a fire extinguishing pipe and a pressure sensing valve. The fire extinguishing tank body is fixed in a linkage control box, the fire extinguishing pipe is laid above the mining lithium-ion battery, and the fire extinguishing pipe is connected to the fire extinguishing tank body through a fire extinguishing agent input pipeline; the pressure sensing valve is located in the second cavity and is arranged on the fire extinguishing agent input pipeline, and is used to open the pressure sensing valve when it is monitored that the pressure of the fire extinguishing pipe changes, so as to extinguish the thermal runaway area; the fire extinguishing pipe is made of heat-sensitive material, and the fire extinguishing tank body stores perfluoroacetone fire extinguishing agent.

As a preferred solution of the system of the present invention, the thermal runaway gas processing device includes a liquid nitrogen tank, a liquid nitrogen input pipeline and a pressure-flow regulating valve. The liquid nitrogen tank is fixed in a linkage control box. The liquid nitrogen input pipeline is located in the second cavity, and one end is connected to the liquid nitrogen tank, and the other end is connected to a microchannel structure of one side wall of the first cavity. A thermal barrier device is provided at the connection between the liquid nitrogen input pipeline and the microchannel structure. When the thermal runaway gas enters the microchannel, the thermal barrier device expands due to heat to open the liquid nitrogen input pipeline, and the liquid nitrogen in the liquid nitrogen tank enters the microchannel and contacts the thermal runaway gas. The pressure-flow regulating valve is provided on the liquid nitrogen input pipeline, and the pressure-flow regulating valve is connected to the linkage control box. After the mining lithium-ion battery has a thermal runaway, the linkage control box is used to control the pressure-flow regulating valve to adjust the flow and pressure of the liquid nitrogen, so that the thermal runaway gas reaches a safe temperature and pressure level after cooling and inerting. A pre-cooling partition area is also provided at the connection between the liquid nitrogen input pipeline and the microchannel structure.

As a preferred solution of the system of the present invention, the linkage control box includes a linkage control device, which is respectively connected to the pressure-flow regulating valve, the pressure sensing valve, the microchannel temperature-pressure composite sensor and the thermal runaway composite gas detection device.

As a preferred solution of the system of the present invention, a microchannel pressure relief valve and a main pressure relief valve are provided on the outer wall of the top of the first cavity, and the microchannel pressure relief valve and the main pressure relief valve are used in conjunction with the pressure-flow regulating valve to jointly regulate the flow and pressure of liquid nitrogen in the microchannel structure so that the thermal runaway gas reaches a safe temperature and pressure level after cooling and inerting.

A method for explosion-proofing a lithium-ion battery for mining is implemented based on the explosion-proofing system for lithium-ion batteries for mining, and the method comprises the following steps:

Step 1: When the thermal runaway gas is discharged from the mining lithium-ion battery due to thermal runaway, the gas collecting and guiding device at the entrance of the microchannel expands after contacting the thermal runaway gas, opens the microchannel to absorb the thermal runaway gas, and blocks and screens out the thermal runaway solid reactants, so as to control the thermal runaway gas and isolate it from the potential fire source; the PCM coating arranged between two adjacent microchannel entrances absorbs and stores the thermal runaway radiation heat energy;

Step 2: After the thermal runaway abnormal signal detection device detects that the temperature, pressure and gas signals exceed the preset threshold, it transmits the abnormal signal to the linkage control device, waiting for the thermal runaway fire extinguishing device and the thermal runaway gas treatment device to respond automatically. If the self-response fails, the linkage control device initiates a secondary active response;

Step 3, after the fire extinguishing pipe of the thermal runaway fire extinguishing device ruptures and loses pressure due to the heat radiated by the thermal runaway of the battery, the pressure sensing valve on the fire extinguishing agent input pipeline is opened to drive the perfluorohexanone fire extinguishing agent to fill the fire extinguishing pipe and extinguish the fire in the thermal runaway area;

Step 4, after the liquid nitrogen input pipeline in the thermal runaway gas treatment device and the thermal barrier device at the connection with the microchannel structure come into contact with the thermal runaway gas, the liquid nitrogen input pipeline is opened due to thermal expansion, and the liquid nitrogen enters the pre-cooling isolation area between the microchannel structure and the liquid nitrogen input pipeline to preliminarily cool the thermal runaway gas; after the battery has thermal runaway, the pressure-flow regulating valve is used in conjunction with the microchannel pressure relief valve and the main pressure relief valve to adjust the flow and pressure of the liquid nitrogen in the microchannel structure so that the thermal runaway gas reaches a safe temperature and pressure level after cooling and inerting; when the thermal runaway gas reaches a safe temperature and pressure level after cooling and inerting, the gas collecting and diversion device is opened to allow the treated mixed gas to enter the recovery pipeline and be collected in the recovery tank;

Step 5, after the mixed gas recovery is completed, the linkage control device controls the liquid nitrogen input pipeline to introduce liquid nitrogen into the microchannel structure again for microchannel cleaning. The thermal runaway radiant heat energy stored in the PCM coating is triggered and activated by the linkage control device, and the heat released by the microchannel structure after the liquid nitrogen is cooled is gradually warmed up to achieve the crushing or removal of the thermal runaway solid reactants blocked in the microchannel structure. When the temperature, pressure and gas signal in the microchannel structure return to normal levels, the cleaning is completed.

Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

1. The present invention creatively combines an explosion-proof battery box with a specially constructed microchannel structure, and couples a thermal runaway abnormal signal detection device, a fire extinguishing device, and a gas processing device together. While meeting the use requirements of lithium-ion battery packs in coal mines, it can effectively prevent the hazards of battery thermal runaway, control the abnormal energy of thermal runaway, prevent the explosion hazard caused by battery thermal runaway, and ensure the safe use of lithium-ion battery packs in explosive environments. The system method is highly reliable and sustainable, and can effectively ensure the recyclable use of the explosion-proof system, thereby improving the safety of lithium-ion batteries used in coal mines.

2. The present invention utilizes a specially constructed microchannel structure, cooperates with a fire extinguishing system and a thermal runaway gas treatment system, provides sufficient contact operating surface to enhance the cooling and inerting efficiency of the thermal runaway gas, and promotes heat exchange to control the thermal runaway energy; and the microchannel design optimizes the internal space layout of the battery box, saving more box space capacity to facilitate the storage of battery packs, and is more suitable for complex conditions and high-risk underground coal mine working environments.

3. The present invention comprehensively designs heat management, gas control and filtering and blocking functions. The micro-pore structure of the microchannel can effectively block and screen out solid reactants produced during thermal runaway, isolate the ignition source and the thermal runaway gas, and eliminate the potential risk of the ignition source; the PCM coating material arranged on the inlet side of the microchannel absorbs the radiant heat energy of the thermal runaway of the storage battery, thereby realizing the rational use of the heat of thermal runaway; because the PCM material absorbs heat in the thermal runaway event and releases it during the cleaning process, the explosion-proof system forms a self-sustaining cycle, reduces dependence on external energy input, improves energy utilization efficiency, and provides more comprehensive safety design protection.

4. The present invention allows the microchannel to maintain reliability after multiple thermal runaway events through a cleaning mechanism, which not only improves the cleaning efficiency of the microchannel structure and ensures the performance stability of the system in continuous operation, but also enables the system to respond and recover quickly when facing continuous or multiple thermal runaway events, and can adapt to underground coal mine operations in high-risk environments, and extend the service life of the system and reduce the long-term operating costs of the system.

5. The explosion-proof system proposed in the present invention can be adjusted and expanded according to battery configurations of different types and sizes. The flexibility embodied by the explosion-proof system enables the system to adapt to various application scenarios, from small portable devices to large industrial battery systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a lithium-ion battery explosion-proof system for mining according to the present invention;

FIG. 2 is a schematic diagram of local details of the microchannel structure of the explosion-proof system in FIG. 1 .

Numbers in the figure: 1-explosion-proof battery box; 2-microchannel structure; 3-fire extinguishing pipe; 4-mining lithium-ion battery; 5-linkage control box; 6-liquid nitrogen input pipeline; 7-fire extinguishing agent input pipeline; 8-pressure sensing valve; 9-recovery pipeline; 10-pressure-flow regulating valve; 11-microchannel pressure relief valve; 12-main pressure relief valve; 13-gas collecting and guiding device; 21-microchannel temperature-pressure composite sensor; 22-microchannel inlet; 23-PCM coating.

Detailed ways

The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

As shown in FIG1 , it is a schematic diagram of the structure of a lithium-ion battery explosion-proof system for mining proposed by the present invention, comprising: an explosion-proof battery box 1, a microchannel structure 2, a thermal runaway abnormal signal detection device, a thermal runaway fire extinguishing device, a thermal runaway gas processing device and a linkage control box 5.

The explosion-proof battery box 1 includes a first cavity and a second cavity, and the microchannel structure 2 is arranged in the first cavity, as shown in FIG2 , and is composed of a series of microchannels on the inner wall of the box. The channels are similar to a honeycomb structure and cover the inner wall of the box to form a gas flow network that captures and guides the gas in an all-round manner. Each layer of the microchannel structure contains multiple parallel microchannels, which are used to increase the cooling area and improve the heat exchange efficiency, so that each area of the microchannel can collect the high-temperature and high-pressure gas after the battery has thermal runaway, and the micro-pore structure of the microchannel can effectively block and screen out the thermal runaway solid reactants. The thermal runaway gas enters the microchannel due to the gas collection effect at the entrance of the microchannel, and each microchannel is finally connected to the main collection chamber, and the bottom of the main collection chamber is connected to the gas recovery pipeline 9. In the microchannel structure, a temperature-pressure composite sensor 21 is arranged at fixed points on both sides along the gas flow direction to detect the temperature signal inside the microchannel and the thermal runaway gas pressure signal, so as to adjust the liquid nitrogen flow rate and flow rate in real time feedback. A gas collecting and guiding device 13 is designed at the entrance of the microchannel to facilitate the collection of thermal runaway gases. It uses a thermosensitive memory material that is closed at low temperatures and opens when encountering hot gases, forming a one-way directional flow structure with the microchannel to prevent the escape of liquid nitrogen and only promote the collection of thermal runaway gases. The main collection chamber of the microchannel is provided with a main pressure relief valve 12, and two microchannel pressure relief valves 11 are arranged on the left and right sides of the main pressure relief valve 12 to prevent the liquid nitrogen from contacting the thermal runaway gas and generating instantaneous local high pressure in the channel. The main collection chamber is a sunken hemispherical structure. The space provided by the main collection chamber can temporarily store a mixture of thermal runaway gas and liquid nitrogen to provide sufficient time and space and to maximize cooling and inerting treatment, and dynamically promote and guide the mixture to gather in the central area of the main collection chamber to reduce the accumulation of substances in the dead corners of the space. The recovery pipeline 9 is connected to the bottom of the main collection chamber through a gas collecting and guiding device 13 equipped with temperature-sensitive materials. The temperature-sensitive material on the surface of the gas collecting and guiding device 13 opens only when the temperature and pressure level after cooling and inerting is reached to ensure that the safely treated gas enters the recovery pipeline 9 and is finally collected in the recovery tank.

The thermal runaway abnormal signal detection device includes a microchannel temperature-pressure composite sensor 21, a thermal runaway composite gas detection device and a linkage alarm device. The detection device is fixed above the battery pack to monitor the thermal runaway gas event of the lithium-ion battery. The linkage alarm device is fixed in the linkage control box to respond to the communication alarm.

The thermal runaway fire extinguishing device includes a fire extinguishing tank, a fire extinguishing pipe 3 and a pressure sensing valve 8. The fire extinguishing tank is fixed in the linkage control box 5; the fire extinguishing tank stores perfluorohexanone fire extinguishing agent to extinguish lithium-ion battery fires; the fire extinguishing pipe 3 is made of a thermosensitive material and laid above the lithium-ion battery pack space. When the battery thermally runs away, the fire extinguishing agent pre-filled in the fire extinguishing pipe 3 will be ejected from the rupture of the thermosensitive material, causing a local pressure change in the fire extinguishing pipe pipeline; the pressure sensing valve 8 opens the valve of the fire extinguishing agent input pipeline 7 after monitoring the pressure change of the fire extinguishing pipeline, and the fire extinguishing agent is driven to continue to fill the fire extinguishing pipeline due to the pressure difference between the pipeline and the fire extinguishing tank, so as to extinguish the fire in the key area of thermal runaway.

The thermal runaway gas processing device includes a liquid nitrogen tank, a liquid nitrogen input pipeline 6 and a pressure-flow regulating valve 10. The liquid nitrogen tank is fixed in the linkage control box 5. The liquid nitrogen input pipeline 6 is directly connected to the microchannel side, and a thermal barrier device is provided at the connection between the liquid nitrogen input pipeline 6 and the microchannel. When the thermal runaway gas enters the microchannel, the thermal barrier device expands due to heat, thereby opening the liquid nitrogen channel. The liquid nitrogen pre-filled in the pipeline enters the microchannel and contacts with the thermal runaway gas to further generate a pressure difference, driving the liquid nitrogen to circulate in the microchannel. The pressure-flow regulating valve 10 is installed on the connection side between the liquid nitrogen input pipeline 6 and the microchannel. Under normal conditions, the valve is half-open. After the battery has thermal runaway, the microchannel temperature-pressure composite sensor 21 will feed back the pressure signal to the linkage control box 5, thereby controlling the pressure-flow regulating valve 10 to accurately adjust the flow and pressure of the liquid nitrogen.

The linkage control box 5 is fixed in the second cavity and connected with the mining lithium-ion battery 4, the sensor and the valve group through lines to receive the detected battery thermal runaway abnormal signal and send a linkage control signal; the linkage control box 5 is connected with the fire extinguishing pipeline and the liquid nitrogen input pipeline 6; the linkage control box 5 contains a linkage control device, a linkage alarm device, a fire extinguishing tank, a liquid nitrogen tank and a recovery tank; the linkage control device is fixed at the bottom of the control box to realize the system coordinated control of the electrical device.

A gas collecting and guiding device 13 is designed at the entrance of the microchannel to facilitate the collection of thermal runaway gases; the gas collecting and guiding device adopts a thermosensitive memory material that is closed at low temperatures and opens when encountering hot gases, forming a one-way directional flow structure with the microchannel to prevent liquid nitrogen from escaping, so as to promote the directional collection of thermal runaway gases.

The microchannel temperature-pressure composite sensor 21 and the linkage control device in the linkage control box 5 constitute a dynamic characteristic signal monitoring system, which can automatically adjust the liquid nitrogen flow rate or flow rate of the pressure release path when abnormal pressure is detected, so as to prevent instantaneous local high pressure when the thermal runaway gas and liquid nitrogen are in direct contact, thereby reducing the risk of local high pressure under abnormal conditions; the microchannel temperature-pressure composite sensor 21 monitors the temperature and pressure signals in the microchannel in real time, and automatically adjusts the liquid nitrogen flow rate and the opening degree of the nozzle through the feedback control system to prevent abnormal temperature and abnormal pressure difference in the channel from causing damage to the microchannel structure and escape of liquid nitrogen vapor.

A gas collecting and guiding device 13 connected to the bottom of the main collecting chamber is designed at the entrance of the gas recovery pipeline 9; the gas collecting and guiding device is made of temperature-sensitive material, and the temperature-sensitive material on the surface of the device is opened only when the temperature and pressure level after cooling and inerting are reached to ensure that the safely treated gas enters the recovery pipeline and is finally collected in the recovery tank.

The connection between the microchannel and the liquid nitrogen pipeline provides a pre-cooling area; the pre-cooling area is to set a pre-cooling area before the liquid nitrogen enters the microchannel to preliminarily cool the thermal runaway gas to reduce the risk of high pressure caused by thermal expansion. At the same time, the liquid nitrogen evaporates and enters the microchannel to optimize the cooling efficiency and prevent the liquid nitrogen from directly affecting the cooling efficiency of the microchannel.

The linkage control device is also equipped with a redundant design of the safety monitoring system; after receiving the thermal runaway signal from the thermal runaway abnormal signal detection device, the safety monitoring system waits for the self-response in the fire extinguishing system and the cooling system. If the self-response mechanism fails to operate successfully, such as due to the failure of the thermosensitive material and other reasons causing the automatic thermal runaway response program errors, the linkage control device will realize the active secondary thermal runaway response, and actively perform thermal runaway fire extinguishing and liquid nitrogen cooling.

There is a self-response mechanism in the fire extinguishing pipe and the liquid nitrogen pipe; the self-response mechanism includes a thermosensitive structure device made of temperature-sensitive material in the fire extinguishing pipe and the liquid nitrogen input pipe, which opens the fire extinguishing channel and the liquid nitrogen input pipe after contacting the high-temperature thermal runaway gas: the fire extinguishing pipe is pre-filled with a full load of fire extinguishing agent, which will be ejected from the rupture of the thermosensitive material, causing the local pressure change in the fire extinguishing pipe, allowing the perfluorohexanone fire extinguishing agent to be driven by the pressure difference to the critical area of thermal runaway; liquid nitrogen forms a local high-pressure area in the pre-cooling area, so that the liquid nitrogen vapor is also driven into the various local low-pressure areas of the microchannel, promoting the flow of liquid nitrogen vapor in the microchannel, so as to realize automatic and rapid response to battery thermal runaway handling in emergency situations.

A PCM phase change material coating is also added to the side surface of the microchannel inlet 22; the PCM phase change material coating is prepared from an organic PCM material and an epoxy resin carrier to achieve better mechanical strength of the coating on the microchannel surface and maintain the thermal stability and long-term durability of the PCM coating 23; because the main way of heat transfer due to thermal runaway in a closed box is thermal radiation, applying the PCM mixed coating to the external surface around the microchannel inlet helps the PCM coating to better absorb radiant heat energy and provide a rapid thermal response.

The microchannel structure in the battery explosion-proof system is designed with a cleaning mechanism for solid reactants that block thermal runaway. After receiving the thermal runaway end signal from the thermal runaway abnormal signal detection device, the response action begins; in order to remove the thermal runaway solid particles that may be blocked at the entrance of the microchannel, the linkage control device controls the liquid nitrogen to be introduced into the microchannel again. After the liquid nitrogen enters the microchannel, the microchannel temperature-pressure composite sensor 21 will feedback a new characteristic signal to the linkage control device, and then control the pressure-flow control valve 10 to adjust the flow rate and flow rate of liquid nitrogen entering the microchannel in real time, so as to achieve a gradual cooling of the microchannel structure after the thermal runaway ends. The thermal runaway solid particles undergo significant volume structure changes due to low-temperature stress, and the new stress generated inside the particles due to the influence of temperature leads to loosening of the overall structure and loss of stability. The thermal runaway abnormal signal detection device detects that the battery thermal runaway has ended and receives a normal temperature signal. Liquid nitrogen is introduced into the microchannel to perform a microchannel clearing procedure. The thermal runaway heat stored in the PCM coating 23 is triggered and activated, and the microchannel cooled by liquid nitrogen is subjected to a temperature recovery treatment. During the temperature recovery process, the solid particle structure becomes more fragile and is broken or removed through the microchannel entrance that is opened after the temperature recovery.

The cleaning mechanism also includes the real-time detection and control of the characteristic temperature and pressure in the channel by the microchannel temperature-pressure composite sensor 21 to achieve the gradual cooling and temperature recovery operation in the microchannel, and to determine whether the characteristic signal of the temperature-pressure composite sensor has returned to the normal level during the cleaning process to determine whether the thermal runaway solid blockage has been completely removed. The PCM coating will not hinder the normal operation of the thermal expansion material at the entrance of the microchannel when the battery has thermal runaway, and can release the stored heat to recover the temperature of the microchannel after the thermal runaway ends, so as to promote the opening of the microchannel entrance again.

The present invention also proposes an explosion-proof method for lithium-ion batteries for mining based on the above-mentioned explosion-proof system, the method comprising the following steps:

Step 1: After the thermal runaway of the mining lithium-ion battery 4 in the mining lithium-ion battery explosion-proof system occurs, the battery safety valve ruptures and discharges the thermal runaway gas with flammable risk, accompanied by the ejection of high-temperature thermal runaway solid reactants. The gas collecting and guiding device 13 at the microchannel inlet 22 expands and opens the channel to absorb the thermal runaway gas after contacting the thermal runaway gas. At the same time, the special structure of the microchannel effectively blocks and screens out the thermal runaway solid reactants, prevents the accumulation of thermal runaway gas, and controls the thermal runaway gas to be isolated from the potential ignition source; the PCM coating 23 arranged along the inlet side of the microchannel begins to absorb and store the thermal runaway radiant heat energy.

Step 2: After the thermal runaway abnormal signal detection device detects that the abnormal temperature, pressure and gas signal exceed the preset action threshold, it transmits the abnormal signal to the linkage control device and waits for the thermal runaway fire extinguishing device and the thermal runaway gas treatment device to respond automatically. If the self-response of the device fails, the linkage control device initiates a secondary active response.

Step 3: The fire extinguishing pipe 3 of the thermal runaway fire extinguishing device ruptures and loses pressure due to the heat radiated by the thermal runaway of the battery, and the pressure sensing valve 8 in the fire extinguishing pipe is opened. Due to the pressure difference between the pipe and the fire extinguishing tank, the perfluorohexanone fire extinguishing agent is driven to respond quickly and fill the fire extinguishing pipe, thereby extinguishing the fire in the key area of the thermal runaway and eliminating the potential ignition source caused by the thermal runaway.

Step 4: After the liquid nitrogen input pipeline 6 in the thermal runaway gas treatment device and the thermal barrier device at the connection with the microchannel come into contact with the thermal runaway gas, it expands due to heat and opens the liquid nitrogen channel. The liquid nitrogen that pre-fills the pipeline first enters the pre-cooling isolation area between the microchannel and the liquid nitrogen input pipeline 6 to optimize the cooling efficiency, and the pressure difference drives the liquid nitrogen to circulate further in the microchannel. The additional specific surface area provided by the microchannel structure increases the liquid-gas contact area and restricts the flow of liquid nitrogen, promoting the heat exchange rate and heat absorption of the evaporated liquid nitrogen. After the battery has thermal runaway, the pressure-flow regulating valve 10 forms a dynamic characteristic signal monitoring system by working in conjunction with the microchannel temperature-pressure composite sensor 21, detects in real time and feeds back the temperature-pressure signal to the linkage control box 5, controls the pressure-flow regulating valve to accurately adjust the flow and pressure of liquid nitrogen, and optimizes the cooling and inerting of the thermal runaway gas; the gas collecting and guiding device 13 in the recovery pipeline 9 is opened only when the thermal runaway gas in the main collection chamber reaches a safe temperature and pressure level after cooling and inerting, to ensure that only the safely treated mixed gas enters the recovery pipeline and is finally collected in the recovery tank.

Step 5: After the thermal runaway end signal, the linkage control device controls the liquid nitrogen input pipeline 6 to re-enter the microchannel for microchannel cleaning, and the microchannel temperature-pressure composite sensor 21 adjusts the flow rate and flow velocity of liquid nitrogen entering the microchannel in real time to achieve gradual cooling; the thermal runaway heat stored in the PCM coating 23 is triggered and activated by the linkage control device, and the heat released by the microchannel after the liquid nitrogen is cooled is gradually warmed up to achieve the crushing or removal of the thermal runaway solid particles blocked in the microchannel structure; the cleaning program verifies whether the characteristic signal of the temperature-pressure composite sensor during the cleaning process has returned to a normal level to determine whether the thermal runaway solid blockage has been completely cleared.

The above embodiments are only for illustrating the technical idea of the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention.

Claims (9)

1. The mining lithium ion battery explosion-proof system is characterized by comprising an explosion-proof battery box body, a micro-channel structure, a thermal runaway abnormal signal detection device, a thermal runaway fire extinguishing device, a thermal runaway gas treatment device and a linkage control box; the explosion-proof battery box comprises a first cavity and a second cavity which are connected, the micro-channel structure is arranged on six inner walls of the first cavity, the micro-channel structure of the inner wall at the top of the first cavity is of a sinking hemispherical structure, a plurality of micro-channel inlets are arranged at the hemispherical edge of the hemispherical structure and the edges of the micro-channel structures of other inner walls, the micro-channel inlet at the bottommost part of the hemispherical edge is provided with a gas collecting and guiding device, the gas collecting and guiding device is connected with a recovery tank body through a recovery pipeline, and the recovery tank body is fixed in a linkage control box; the mining lithium ion battery is arranged on the micro-channel structure at the bottom of the first cavity; the linkage control box is arranged in the second cavity;

The thermal runaway abnormal signal detection device is connected with the linkage control box, and the thermal runaway fire extinguishing device and the thermal runaway gas treatment device are respectively connected with the linkage control box; the thermal runaway abnormal signal detection device is used for detecting temperature, pressure and gas signals in the micro-channel structure, and after the temperature, pressure and gas signals exceed preset thresholds, the abnormal signals of the temperature, pressure and gas are sent to the linkage control box, the linkage control box controls the thermal runaway fire extinguishing device to extinguish the fire of the thermal runaway area, and meanwhile controls the thermal runaway gas treatment device to cool the thermal runaway gas and recycle the thermal runaway gas into the recycling tank until the temperature, pressure and gas signals in the micro-channel structure are restored to normal levels.

2. The mining lithium ion battery explosion protection system according to claim 1, wherein a PCM coating is applied between two adjacent microchannel inlets, the PCM coating being made of an organic PCM material and an epoxy resin carrier.

3. The explosion-proof system of a mining lithium ion battery according to claim 1, wherein the gas collection and flow guide device is made of a heat sensitive memory material which is closed at a low temperature and is opened when hot gas is encountered, and a unidirectional directional flow structure is formed with a lowest micro-channel inlet.

4. The mining lithium ion battery explosion-proof system according to claim 1, wherein the thermal runaway abnormal signal detection device comprises a micro-channel temperature-pressure composite sensor, a thermal runaway composite gas detection device and a linkage alarm device which are respectively connected with a linkage control box; a plurality of micro-channel temperature-pressure composite sensors are arranged around the micro-channel structure of all the inner walls and are used for detecting temperature and pressure signals in the micro-channel structure; the thermal runaway composite gas detection device is arranged above the mining lithium ion battery and is used for detecting a gas signal in the first cavity; the linkage alarm device is used for sending abnormal signals of temperature, pressure and gas to the linkage control box after the temperature, pressure and gas signals exceed preset thresholds, and the linkage alarm device is fixed in the linkage control box.

5. The mining lithium ion battery explosion-proof system according to claim 4, wherein the thermal runaway extinguishing device comprises an extinguishing tank body, an extinguishing pipe and a pressure sensing valve, the extinguishing tank body is fixed in the linkage control box, the extinguishing pipe is laid above the mining lithium ion battery, and the extinguishing pipe is connected with the extinguishing tank body through an extinguishing agent input pipeline; the pressure sensing valve is positioned in the second cavity and is arranged on the fire extinguishing agent input pipeline and used for opening the pressure sensing valve to extinguish the fire in the thermal runaway area when the pressure of the fire extinguishing pipe is monitored to change; the fire extinguishing pipe is made of heat sensitive material, and the fire extinguishing tank is internally stored with perfluoro-ethyl ketone extinguishing agent.

6. The mining lithium ion battery explosion-proof system according to claim 5, wherein the thermal runaway gas treatment device comprises a liquid nitrogen tank body, a liquid nitrogen input pipeline and a pressure-flow regulating valve, wherein the liquid nitrogen tank body is fixed in the linkage control box, the liquid nitrogen input pipeline is positioned in the second cavity, one end of the liquid nitrogen input pipeline is connected with the liquid nitrogen tank body, and the other end of the liquid nitrogen input pipeline is connected with a micro-channel structure of one side wall of the first cavity; the connection part of the liquid nitrogen input pipeline and the micro-channel structure is provided with a thermosensitive blocking device, when the thermal runaway gas enters the micro-channel, the thermosensitive blocking device expands under heating to open the liquid nitrogen input pipeline, and the liquid nitrogen in the liquid nitrogen tank body enters the micro-channel and contacts with the thermal runaway gas; the pressure-flow regulating valve is arranged on the liquid nitrogen input pipeline and is connected with the linkage control box, and after the mining lithium ion battery is subjected to thermal runaway, the linkage control box is used for controlling the pressure-flow regulating valve to regulate the flow and the pressure of the liquid nitrogen, so that the thermal runaway gas reaches the safe temperature and the pressure level after cooling and inerting; the joint of the liquid nitrogen input pipeline and the micro-channel structure is also provided with a pre-cooling partition area.

7. The mining lithium ion battery explosion-proof system according to claim 6, wherein the linkage control box comprises a linkage control device, and the linkage control device is respectively connected with a pressure-flow regulating valve, a pressure sensing valve, a micro-channel temperature-pressure composite sensor and a thermal runaway composite gas detection device.

8. The mining lithium ion battery explosion-proof system according to claim 6, wherein the outer wall of the top of the first cavity is provided with a micro-channel relief valve and a main relief valve, and the micro-channel relief valve and the main relief valve are used for being matched with a pressure-flow regulating valve to jointly regulate the flow and pressure of liquid nitrogen in the micro-channel structure, so that the thermal runaway gas reaches the safe temperature and pressure level after cooling inerting.

9. The mining lithium ion battery explosion-proof method based on the mining lithium ion battery explosion-proof system of claim 7 is realized, and is characterized by comprising the following steps:

Step 1, after thermal runaway gas is discharged from a lithium ion battery for mining, a gas collecting and guiding device at an inlet of a micro-channel is expanded to open the micro-channel to absorb the thermal runaway gas after contacting the thermal runaway gas, and a solid reactant for removing the thermal runaway is separated from the thermal runaway gas, so that the thermal runaway gas is controlled to be isolated from a potential fire source; the PCM coating arranged between the inlets of two adjacent micro-channels absorbs and stores the thermal runaway radiation heat energy;

Step 2, after the thermal runaway abnormal signal detection device detects that the temperature, the pressure and the gas signals exceed the preset threshold, transmitting the abnormal signals to the linkage control device, waiting for self-response of the thermal runaway fire extinguishing device and the thermal runaway gas treatment device, and if the self-response fails, starting secondary active response by the linkage control device;

Step 3, after the fire extinguishing pipe of the thermal runaway fire extinguishing device is broken and pressured by heat radiated by thermal runaway of the battery, a pressure sensing valve on a fire extinguishing agent input pipeline is opened to drive the perfluorinated hexanone fire extinguishing agent to fill the fire extinguishing pipe, and fire is extinguished in the thermal runaway area;

Step 4, after the liquid nitrogen input pipeline in the thermal runaway gas treatment device contacts with the thermal runaway gas, the thermal sensitive blocking device at the joint of the micro-channel structure is heated to expand to open the liquid nitrogen input pipeline, and the liquid nitrogen enters a pre-cooling partition area between the micro-channel structure and the liquid nitrogen input pipeline to primarily cool the thermal runaway gas; after thermal runaway occurs in the battery, the pressure-flow regulating valve is matched with the micro-channel pressure relief valve and the main pressure relief valve for use, and the flow and the pressure of liquid nitrogen in the micro-channel structure are regulated, so that the thermal runaway gas reaches the safe temperature and pressure level after cooling inertization; when the thermal runaway gas reaches the safe temperature and pressure level after cooling inerting, opening the gas collecting and guiding device to enable the processed mixed gas to enter a recovery pipeline and be collected in a recovery tank body;

and 5, after the mixed gas is recovered, controlling the liquid nitrogen input pipeline to be led into the liquid nitrogen again by the linkage control device to clear the micro-channel, triggering and activating the thermal runaway radiation heat energy stored in the PCM coating by the linkage control device, gradually tempering the heat released by the micro-channel structure after the liquid nitrogen is cooled, crushing or rejecting the thermal runaway solid reactant blocked in the micro-channel structure, and finishing the clearing after the temperature, the pressure and the gas signals in the micro-channel structure are restored to normal levels.