High-capacity battery thermal runaway multi-parameter monitoring and early warning device and method

Abstract

The invention relates to a high-capacity battery thermal runaway multi-parameter monitoring and early warning device and method, and belongs to the technical field of lithium battery thermal runaway early warning. The device comprises an air outlet pipe, one end of the air outlet pipe penetrates through a shell of a battery and extends into the battery, the other end of the air outlet pipe is provided with a three-way valve, and the three ends of the three-way valve are an end a, an end b and an end c respectively; the end a of the three-way valve is connected with the air outlet pipe, and the end b of the three-way valve is connected with the collecting pipe; one end, far away from the three-way valve, of the communicating pipe is connected with a gas analyzer; a thermocouple is attached to the surface of the battery; the device further comprises a data acquisition instrument and an upper computer, the thermocouple and the gas pressure sensor are electrically connected with the data acquisition instrument simultaneously, the data acquisition instrument is electrically connected with the upper computer, and the gas analyzer is in communication connection with the upper computer. According to the device and the method, early warning can be given at the initial stage of thermal runaway, and the early warning timeliness is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery thermal runaway warning, and in particular relates to a large-capacity battery thermal runaway multi-parameter monitoring and warning device and method. Background Art

[0002] With the booming development of the new energy industry, the application of lithium batteries in energy storage is becoming more and more common. The thermal runaway characteristics of lithium batteries are one of the key factors that cause fire and explosion accidents in energy storage power stations. During thermal runaway, the organic solvent and electrolyte inside the battery may decompose and burn during the thermal runaway process, causing the temperature inside the battery to rise, gas to be generated, and the air pressure to rise.

[0003] Existing lithium battery thermal runaway warnings mostly rely on thermocouples attached to the surface of lithium batteries to monitor the surface temperature of lithium batteries, and also rely on gas sensors to monitor the gas composition emitted by lithium battery thermal runaway. However, the internal temperature and gas of the battery are difficult to dissipate to the outside, resulting in poor timeliness in monitoring external signals such as battery surface temperature and external gas.

[0004] To this end, it is necessary to monitor the internal pressure and gas concentration of lithium batteries in real time to achieve the purpose of early warning of thermal runaway. Summary of the invention

[0005] The present invention provides a large-capacity battery thermal runaway multi-parameter monitoring and early warning device and method, which are used to solve the above-mentioned problem.

[0006] A multi-parameter monitoring and early warning device for thermal runaway of a large-capacity battery of the present invention comprises an air outlet pipe, one end of the air outlet pipe passes through the outer shell of the battery and extends into the interior of the battery, a three-way valve is installed at the other end of the air outlet pipe, and the three ends of the three-way valve are respectively arranged as end a, end b and end c, end a of the three-way valve is connected to the air outlet pipe, end b of the three-way valve is connected to a collection pipe, one end of the collection pipe away from the three-way valve is connected to a gas pressure sensor; end c of the three-way valve is connected to a connecting pipe, one end of the connecting pipe away from the three-way valve is connected to a gas analyzer; a thermocouple is attached to the surface of the battery; a data acquisition instrument and a host computer are also included, the thermocouple and the gas pressure sensor are electrically connected to the data acquisition instrument at the same time, the data acquisition instrument is electrically connected to the host computer, and the gas analyzer is communicatively connected to the host computer.

[0007] Furthermore, a solenoid valve is installed on the connecting pipe, and the solenoid valve is electrically connected to the upper machine.

[0008] The gas analyzer does not analyze the gas composition and volume fraction all the time, but only starts analyzing the gas composition and volume fraction after the second-level warning.

[0009] Furthermore, a fixture assembly is also included, and the fixture assembly includes: A lower clamping plate is located at the bottom side of the battery, and the upper surface of the lower clamping plate contacts the lower surface of the battery; The upper clamping plate is located on the upper side of the battery, the lower surface of the upper clamping plate contacts the upper surface of the battery, a sleeve hole is opened in the middle of the upper clamping plate, and the diameter of the sleeve hole is equal to the outer diameter of the outlet pipe; the upper clamping plate is sleeved on the outlet pipe by relying on the sleeve hole; A plurality of threaded rods, each threaded rod passes through the upper clamping plate and the lower clamping plate at the same time; both ends of each threaded rod are respectively threadedly connected with a nut, the upper nut contacts the upper surface of the upper clamping plate, and the lower nut contacts the lower surface of the lower clamping plate.

[0010] The clamp assembly ensures the stability of the air outlet pipe and can ensure that the air outlet pipe will not shake at will through the sleeve hole, thereby ensuring the stability of the air outlet pipe.

[0011] Furthermore, the thermocouple is arranged in the middle of the large surface of the battery.

[0012] The middle part of the battery's large surface is more sensitive to battery surface temperature monitoring, so it is more reasonable to set the thermocouple at this position. The temperature at the middle position is more balanced and universal than at other positions.

[0013] Furthermore, the air outlet pipe is a steel pipe, and the inner wall of the steel pipe is smooth.

[0014] The rough surface will produce resistance and affect the gas flow speed. In addition, the rough wall surface will easily cause the movement of fluid molecules in the pipe to become disordered during turbulent flow, and frequently collide with the pipe wall.

[0015] Furthermore, a large-capacity battery thermal runaway multi-parameter monitoring and early warning method comprises the following steps: S1: Build a multi-parameter monitoring and early warning device for thermal runaway of large-capacity batteries; S2: The thermocouple monitors the temperature data on the battery surface and transmits it to the data acquisition instrument; the gas pressure sensor monitors the gas pressure data inside the battery and transmits it to the data acquisition instrument, which transmits the temperature data and gas pressure data to the host computer after they are stabilized; S3: Set judgment conditions; Condition 1: Within time T, the air pressure rises above the threshold value P; Condition 2: The rising slope of the air pressure exceeds the threshold value K, and at the same time, the rising slope of the temperature data exceeds the threshold value S; Condition 3: The upper explosion limit of the combustible gas inside the lithium battery exceeds 80% of the upper explosion limit of the combustible gas when the lithium battery valve is opened; S4: The host computer determines whether it is a level 1 warning; If the host computer determines that condition one is met but condition two is not met, the host computer will issue a first-level warning; If not, the host computer will not issue a first-level warning; S5: The host computer determines whether it is a level 2 warning; If the host computer determines that both conditions 1 and 2 are met, but condition 3 is not met, the host computer will issue a secondary warning and open the solenoid valve; If not, the host computer will not issue a secondary warning; S6: The host computer determines whether it is a level 3 warning; If the host computer determines that conditions one, two and three are met at the same time, the host computer will issue a level three warning; If not, the host computer will not issue a third-level warning.

[0016] Furthermore, T=120s; P=10KPa; K=0.15KPa / s; S=0.1℃ / s.

[0017] Beneficial effects: The system can be applied to large-capacity lithium batteries of various types and sizes, including electric vehicles, energy storage systems, and other fields that require high-safety battery systems. By using advanced gas and pressure measurement technology on the external equipment of lithium battery cells (modules), it can accurately monitor the gas composition and pressure changes inside the battery, achieve accurate detection of thermal runaway, and issue an early warning at the beginning of battery thermal runaway, significantly improving the timeliness of the warning.

[0018] The present invention can effectively warn the lithium battery before the safety valve opens, and the effect is obvious, which makes up for the shortcomings of the existing early warning method that uses external parameter change early warning with high false alarm rate, missed alarm rate and untimely response. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the device.

[0020] Figure 2 It is a schematic diagram of the structure when the lithium battery is connected to the upper clamping plate and the lower clamping plate; Figure 3 It is a flow chart of the early warning method; Figure 4 It is a temperature and gas pressure data graph during the thermal runaway process of lithium battery; Figure 5 It is a data graph of the temperature change rate during the thermal runaway process of lithium batteries; Figure 6 It is a data graph of the gas pressure change rate during the thermal runaway process of lithium battery; Figure 7 It is a diagram of the composition of the gas inside the lithium battery during thermal runaway of the lithium battery.

[0021] 1. Outlet pipe; 2. Lower clamping plate; 3. Upper clamping plate; 4. Threaded rod; 5. Three-way valve; 6. Gas pressure sensor; 7. Thermocouple; 8. Solenoid valve; 9. Connecting pipe; 10. Gas analyzer; 11. Data acquisition instrument; 12. Host computer. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1: See Figure 1 , a multi-parameter monitoring and early warning device for thermal runaway of a large-capacity battery, including an outlet pipe 1, one end of which is penetrated through the outer shell of a 3.2V 314Ah lithium battery, and the end of the outlet pipe 1 is inside the battery. The specific operation is as follows: a hole is punched on the outer shell of the above-mentioned lithium battery, and the hole is recorded as a perforation. Avoid damaging the inside of the battery when punching the hole, and then insert one end of the outlet pipe 1 into the perforation. The outlet pipe 1 is a steel pipe, and the steel pipe must have the characteristics of high temperature resistance, corrosion resistance and smooth inner wall. Then, the outer wall of the outlet pipe 1 is sealed with the inner wall of the above-mentioned perforation by sealing means. In this embodiment, the sealing method is: the outer wall of the outlet pipe 1 and the inner wall of the hole are bonded and sealed with high temperature resistant glue.

[0024] See Figure 1 and Figure 2 , and also includes a clamp assembly for ensuring that the outlet pipe 1 is stably connected to the battery, the clamp assembly including: The lower clamping plate 2 is located below the battery, and the upper surface of the lower clamping plate 2 contacts the lower surface of the battery; The upper clamping plate 3 is located above the battery, the lower surface of the upper clamping plate 3 contacts the upper surface of the battery, and a sleeve hole is opened in the middle of the upper clamping plate 3, and the diameter of the sleeve hole is equal to the outer diameter of the outlet pipe 1. The upper clamping plate 3 is sleeved on the outlet pipe 1 by relying on the sleeve hole.

[0025] A plurality of threaded rods 4, each threaded rod 4 passes through the upper clamping plate 3 and the lower clamping plate 2 at the same time. A nut is threadedly connected to each end of each threaded rod 4, the nut at the upper end contacts the upper surface of the upper clamping plate 3, and the nut at the lower end contacts the lower surface of the lower clamping plate 2. For a threaded rod 4, when the two nuts at both ends of the threaded rod 4 are screwed and approached to each other, the two nuts force the upper clamping plate 3 and the lower clamping plate 2 to approach each other, so that the upper clamping plate 3 and the lower clamping plate 2 clamp the upper and lower surfaces of the battery together, and because the upper clamping plate 3 is set in the middle position of the air outlet pipe 1 by means of the sleeve hole, the upper clamping plate 3 supports the middle part of the air outlet pipe 1, so the air outlet pipe 1 is not easy to shake, and the connection stability between the air outlet pipe 1 and the battery is guaranteed.

[0026] One end of the outlet pipe 1 away from the battery is outside the battery, and a three-way valve 5 is installed at this end of the outlet pipe 1. The three ends of the three-way valve 5 are respectively end a, end b and end c, wherein end a is connected to the corresponding end of the outlet pipe 1 through a flange. The valve core of the three-way valve 5 is manually controlled to rotate, and when monitoring the thermal runaway of the lithium battery, it is necessary to make end a of the three-way valve 5 connected to end b and end c at the same time.

[0027] The b end of the three-way valve 5 is connected to a collection pipe through a flange, and the end of the collection pipe away from the three-way valve 5b is connected to a gas pressure sensor 6 through a threaded connection; the gas pressure sensor has a measurement range of 0-10MPa, RS485 communication, 7 effective digits, and an accuracy of 0.05-0.5. The gas pressure sensor 6 has high sensitivity and fast response speed. Its measurement range is suitable for thermal runaway pressure conditions, and the response time is less than 10 milliseconds.

[0028] Thermocouple 7 is attached to the outer surface of the lithium battery. Thermocouple 7 is arranged at the center of the large surface of the lithium battery. Thermocouple 7 adopts K-type thermocouple, and the temperature measurement range is -40~1150℃, and the accuracy is ≤±1.5℃, 0.4%. Thermocouple 7 and gas pressure sensor 6 are electrically connected to data acquisition instrument 11, and data acquisition instrument 11 is electrically connected to host computer 12. The data monitored by gas pressure sensor 6 and thermocouple 7 are first transmitted to data acquisition instrument 11, and data acquisition instrument 11 transmits the data to host computer 12 after stabilization. Host computer 12 adopts computer and has data processing system, which can process various types of collected data. Host computer 12 has the function of data visualization and early warning through software.

[0029] The c-end of the three-way valve 5 is connected to a solenoid valve 8 through a flange. The solenoid valve 8 is in a closed state. The solenoid valve 8 is electrically connected to the host computer 12. According to the signal of the host computer 12, the host computer 12 can control the solenoid valve 8 to open. The solenoid valve 8 is resistant to high temperatures and acts quickly, and the opening and closing time is less than 10 milliseconds. The end of the solenoid valve 8 away from the c-end of the three-way valve 5 is connected to a connecting pipe 9 through a flange. When the solenoid valve 8 is opened, the connecting pipe 9 is connected to the a-end, b-end and c-end of the three-way valve 5. The end of the connecting pipe 9 away from the solenoid valve 8 is connected to a gas analyzer 10. The gas analyzer 10 can be connected to the connecting pipe 9. When the solenoid valve 8 is opened, the gas in the outlet pipe 1 can flow into the connecting pipe 9 through the a-end and c-end of the three-way valve 5, and finally enter the gas analyzer 10. The gas analyzer 10 belongs to the prior art and can quantitatively analyze various mixed gases (such as hydrogen, carbon monoxide, methane, etc.) that may be produced by battery thermal runaway. The principle is: based on the characteristic absorption of infrared light by different gases, the gas composition and the volume ratio of the corresponding components are measured. The gas analyzer 10 is electrically connected to the host computer 12 via an RS485 data line, and can transmit the monitored gas composition and the corresponding volume ratio to the host computer.

[0030] The principle of this device is: When a battery experiences thermal runaway, gas is generated inside the battery. The gas can flow from the outlet pipe 1 through the a and b ends of the three-way valve 5 and contact the gas pressure sensor 6. The gas pressure sensor 6 can monitor the pressure data of the gas inside the battery. Since the solenoid valve 8 is in a closed state at this time, the gas analyzer 10 cannot contact the gas through the c end of the three-way valve 5 and does not analyze the gas. The thermocouple 7 is on the surface of the battery and can monitor the temperature data of the battery surface. The pressure data and temperature data are transmitted to the data acquisition device 11, and then transmitted to the host computer 12 by the data acquisition device 11. The host computer 12 decides whether to issue a first-level warning or a second-level warning based on the values ​​of the pressure data and the temperature data; When the second-level warning is triggered, the host computer 12 opens the solenoid valve 8, and the gas analyzer 10 can contact the gas in the connecting pipe 9 through the c of the three-way valve 5. The gas in the outlet pipe 1 quickly flows into the gas analyzer 10 due to the pressure difference. The gas analyzer 10 analyzes the content of various components in the gas and transmits it to the host computer 12. The host computer 12 calculates the upper explosion limit of the gas in the outlet pipe 1. If the upper explosion limit of the gas in the outlet pipe 1 is greater than or equal to 80% of the upper explosion limit of the gas when the lithium battery valve is opened, the host computer 12 issues a third-level warning.

[0031] Example 2: See Figure 3 , a large-capacity battery thermal runaway multi-parameter monitoring and early warning method, comprising the following steps: S1: Build a multi-parameter monitoring and early warning device for thermal runaway of large-capacity batteries; S2: The thermocouple 7 monitors the temperature data of the battery surface and transmits it to the data acquisition device 11; the gas pressure sensor 6 monitors the gas pressure data inside the battery and transmits it to the data acquisition device 11, and the data acquisition device 11 transmits the temperature data and gas pressure data to the host computer 12 after stabilization; S3: Set judgment conditions.

[0032] Condition 1: within a time period T, the air pressure rises above a threshold value P; in this embodiment, T=120s, P=10KPa.

[0033] Condition 2: The rising slope of the air pressure exceeds the threshold value K, and at the same time, the rising slope of the temperature data exceeds the threshold value S; in this embodiment, K=0.15KPa / s; S=0.1℃ / s; Condition 3: The upper explosion limit of the combustible gas inside the lithium battery exceeds 80% of the upper explosion limit of the combustible gas when the lithium battery valve is opened.

[0034] S4: The host computer determines whether it is a level 1 warning; If the host computer determines that condition one is met but condition two is not met, the host computer will issue a first-level warning; If not, the host computer will not issue a first-level warning; The meaning of the first-level warning is that the host computer 12 sends out a first-level sound and light alarm, and the host computer 12 sends out a corresponding sound and a corresponding color of light.

[0035] S5: The host computer determines whether it is a level 2 warning; If the host computer determines that both condition 1 and condition 2 are satisfied, but condition 3 is not satisfied, the host computer issues a secondary warning and opens the solenoid valve 8; If no, the host computer does not issue a secondary warning and does not open the solenoid valve 8; The meaning of the second-level warning is that the host computer 12 sends out a second-level sound and light alarm, and the host computer 12 sends out a corresponding sound and a corresponding color of light.

[0036] S6: The host computer determines whether it is a level 3 warning; If the host computer determines that conditions one, two and three are met at the same time, the host computer will issue a level three warning; If not, the host computer will not issue a third-level warning; The meaning of the third-level warning is: cutting off the circuit of the lithium battery and extinguishing the fire and cooling the lithium battery.

[0037] Example description: Figure 4It is a graph of pressure and temperature data during the thermal runaway of a lithium battery. According to the warning method of Example 2, the air pressure is 114.275KPa at 469s, and reaches 124.292KPa at 589s. The gas pressure rises by more than 10KPa within 120s, satisfying condition 1; and the pressure and temperature data from 469s to 589s, and the slope of the pressure rise does not exceed the threshold value K=0.15KPa / s, and at the same time, the slope of the temperature data rise does not exceed the threshold value S=0.1℃ / s, so the host computer determines that a first-level warning is needed, so the host computer 12 issues a first-level warning after 589s; See Figure 5 and Figure 6 , 589s-928s, all meet condition 1. At 928s, the temperature rise rate reaches above 0.1℃ / s, but the air pressure rise rate is 0.144KPa / s at this time, so it does not reach the warning threshold. When condition 1 is met, condition 2 is not met, so the second-level warning is not issued. However, at 959s, the air pressure rise rate reaches 0.15KPa / s, and the temperature rise rate is 0.111℃ / s at this time, both reaching the set threshold. When condition 1 is met, condition 2 is also met. At this time, the host computer 12 issues a second-level warning; at the same time as the second-level warning, the host computer 12 controls the solenoid valve 8 to open.

[0038] After the solenoid valve 8 is opened, the gas is quickly introduced into the gas analyzer 10 through the connecting pipe 9, and the gas analyzer 10 analyzes the gas composition and the volume ratio of the corresponding components. The host computer 12 starts to calculate the upper explosion limit of the combustible gas from 959s. And at 1246s, the upper explosion limit of the combustible gas is greater than or equal to 80% of the upper explosion limit of the gas when the lithium battery valve is opened. When conditions one and two are met and condition three is met, the host computer starts a level three warning.

[0039] Specifically, at 1246s, the gas analyzer 10 analyzes the gas components and the volume proportions of the corresponding components. Figure 7 .

[0040] from Figure 7 It can be seen that the gas components mainly include: H2, CO2, CO, CH4 and C2H4; the proportions of each component are: 46.7%, 28.7%, 9.2%, 8.3% and 7.1% respectively. Since CO2 is not a flammable gas, it is not used to calculate the upper explosion limit. According to the empirical formula, the upper explosion limit of the mixed gas is calculated as: UEL=(P1+P2+P3+P4) / (P1 / UEL1+P2 / UEL2+P3 / UEL3+P4 / UEL4)≈47.8% Among them, UEL is the upper explosion limit of the mixed gas; P1 is the volume percentage of hydrogen; P2 is the volume percentage of carbon monoxide; P3 is the volume percentage of methane; P4 is the volume percentage of ethylene; UEL1 is the upper explosion limit of hydrogen, which is 75.6%; UEL2 is the upper explosion limit of carbon monoxide, which is 74.2%; UEL3 is the upper explosion limit of methane, which is 15%; UEL4 is the upper explosion limit of ethylene, which is 36%; the calculated upper explosion limit of the mixed gas at 1246s is about 47.8%, which just reaches the set upper explosion limit threshold UEL 三级预警 =The upper explosion limit of the gas when the valve is opened*80%=57.75%*80%≈47.8%; therefore, the third-level warning is activated.

[0041] Among them, 57.75% is the actual test value of the gas explosion limit when the valve of a 3.2V 314Ah lithium battery is opened. Specifically, the explosion limit judgment threshold of the three-level warning comes from: the average value of multiple test results shows that when the valve of a 3.2V 314Ah lithium battery is opened for 1417s, the proportions of H2, CO2, CO, CH4 and C2H4 are 60.8%, 9.5%, 13.3%, 9.2% and 7.2% respectively. The explosion limit of the combustible gas when the valve of the above lithium battery is opened is calculated by the above empirical formula: UEL 1417s =59.75%. This solution uses a certain proportion (80%) of the upper explosion limit when the valve is opened as the third-level warning threshold of the combustible gas concentration, that is, when the gas analyzer detects that the upper explosion limit of the combustible gas reaches or exceeds UEL 三级预警 =80%×UEL 1417s =59.75%×0.8=47.8%, the third-level warning is triggered.

[0042] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A multi-parameter monitoring and early warning device for thermal runaway of large-capacity batteries, characterized in that: It includes an air outlet pipe, one end of which passes through the battery shell and extends into the battery, and a three-way valve is installed at the other end of the air outlet pipe. The three ends of the three-way valve are respectively arranged as end a, end b and end c. End a of the three-way valve is connected to the air outlet pipe, end b of the three-way valve is connected to a collection tube, and one end of the collection tube away from the three-way valve is connected to a gas pressure sensor; end c of the three-way valve is connected to a connecting tube, and one end of the connecting tube away from the three-way valve is connected to a gas analyzer; a thermocouple is attached to the surface of the battery; it also includes a data acquisition instrument and a host computer, the thermocouple and the gas pressure sensor are electrically connected to the data acquisition instrument at the same time, the data acquisition instrument is electrically connected to the host computer, and the gas analyzer is communicatively connected to the host computer.

2. According to claim 1, a large-capacity battery thermal runaway multi-parameter monitoring and early warning device is characterized in that: The connecting pipe is provided with a solenoid valve, which is electrically connected to the upper machine.

3. A large-capacity battery thermal runaway multi-parameter monitoring and early warning device according to claim 2, characterized in that: Also included is a fixture assembly, the fixture assembly comprising: A lower clamping plate is located below the battery, and an upper surface of the lower clamping plate contacts a lower surface of the battery; The upper clamping plate is located above the battery, the lower surface of the upper clamping plate contacts the upper surface of the battery, a sleeve hole is opened in the middle of the upper clamping plate, and the diameter of the sleeve hole is equal to the outer diameter of the outlet pipe; the upper clamping plate is sleeved on the outlet pipe by relying on the sleeve hole; A plurality of threaded rods, each threaded rod passes through the upper clamping plate and the lower clamping plate at the same time; both ends of each threaded rod are respectively threadedly connected with a nut, the nut at the upper end contacts the upper surface of the upper clamping plate, and the nut at the lower end contacts the lower surface of the lower clamping plate.

4. A large-capacity battery thermal runaway multi-parameter monitoring and early warning device according to claim 3, characterized in that: The thermocouple is arranged in the middle of the large surface of the battery.

5. A large-capacity battery thermal runaway multi-parameter monitoring and early warning device according to claim 3, characterized in that: The air outlet pipe is a steel pipe, and the inner wall of the steel pipe is smooth.

6. A large-capacity battery thermal runaway multi-parameter monitoring and early warning method, based on the large-capacity battery thermal runaway multi-parameter monitoring and early warning device according to claim 2, characterized in that: The following steps are involved: S1: Build a multi-parameter monitoring and early warning device for thermal runaway of large-capacity batteries; S2: The thermocouple monitors the temperature data on the battery surface and transmits it to the data acquisition instrument; the gas pressure sensor monitors the gas pressure data inside the battery and transmits it to the data acquisition instrument, which transmits the temperature data and gas pressure data to the host computer after they are stabilized; S3: Set judgment conditions; Condition 1: Within time T, the air pressure rises above the threshold value P; Condition 2: The rising slope of the air pressure exceeds the threshold value K, and at the same time, the rising slope of the temperature data exceeds the threshold value S; Condition 3: The upper explosion limit of the combustible gas inside the lithium battery exceeds 80% of the upper explosion limit of the combustible gas when the lithium battery valve is opened; S4: The host computer determines whether it is a level 1 warning; If the host computer determines that condition one is met but condition two is not met, the host computer will issue a first-level warning; If not, the host computer will not issue a first-level warning; S5: The host computer determines whether it is a level 2 warning; If the host computer determines that both conditions 1 and 2 are met, but condition 3 is not met, the host computer will issue a secondary warning and open the solenoid valve; If not, the host computer will not issue a secondary warning and will not open the solenoid valve; S6: The host computer determines whether it is a level 3 warning; If the host computer determines that conditions one, two and three are met at the same time, the host computer will issue a level three warning; If not, the host computer will not issue a third-level warning.

7. A large-capacity battery thermal runaway multi-parameter monitoring and early warning method according to claim 6, characterized in that: The T=120s; P=10KPa; K=0.15KPa / s; S=0.1°C / s.

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