Method and device for measuring volume of battery thermal runaway produced gas and electrolyte steam under normal pressure

Abstract

The invention discloses a method and a device for measuring battery thermal runaway produced gas and electrolyte vapor volume under normal pressure conditions. The device comprises a bearing device, a conveying device and a collecting and measuring device, the bearing device comprises a rack and a fastening device; the rack bears the test piece and supports the conveying device and the collecting and measuring device; a support frame of the rack comprises a base, and the base is used for placing a test piece and a fastening device; the base provides a stable supporting foundation for a test piece, and the fastening device comprises a screw rod, a pressing plate and a gas collecting port; the screw rods are arranged on the base of the supporting frame, a gap is formed between the two screw rods, and the gap between the two screw rods is used for placing a test piece; the test piece is a battery; the screw rod is connected with a pressing plate, the pressing plate is provided with a gas collecting port, and the gas collecting port corresponds to a safety valve of a test piece and is hermetically connected with the test piece; and gas and electrolyte vapor generated by out-of-control of the battery are prevented from overflowing. According to the invention, measurement and analysis of the out-of-control gas production of the battery and the electrolyte steam are realized under normal pressure.

Description

Technical Field

[0001] The invention relates to a method and a device for measuring gas production during thermal runaway of a battery and electrolyte vapor volume at normal pressure, belonging to the technical field of battery fire safety. Background Art

[0002] As an important part of new energy technology, lithium-ion batteries have been rapidly developed and widely used around the world. However, with the rapid development of the lithium battery industry, its safety issues have become increasingly prominent, especially the occurrence of fire accidents, which pose a serious threat to people's lives and property. In recent years, there have been many fire accidents related to lithium-ion batteries around the world. These accidents have not only caused huge economic losses, but also aroused widespread public concern about the safety of lithium batteries. For example, on April 18, 2022, a fire broke out at the Chandler lithium battery storage facility in Arizona, USA, which lasted for nearly a week, causing local residents to evacuate urgently.

[0003] Lithium-ion batteries will trigger a series of exothermic reactions under abuse conditions, causing the battery temperature to rise, and high temperature will further accelerate the exothermic reaction. When this process gets out of control, oxygen and a large amount of flammable gas will be generated inside the battery, which will then evolve into a fire or even an explosion. Among them, the battery electrolyte is a mixed solution of lithium salt and organic solvent with a boiling point of about 100°C. Therefore, during thermal runaway, the high temperature inside the battery causes a large amount of electrolyte to vaporize, forming a large amount of electrolyte vapor and toxic smoke, which further increases the combustion and toxicity hazards of lithium battery fires. The current means of measuring battery thermal runaway smoke is usually to use a closed explosion-proof container, but when the battery produces smoke, the container cannot be heated, and the electrolyte vapor will quickly liquefy, and a pressure environment will be formed in the container at this time, which is inconsistent with the actual operating environment of the battery. At this stage, there is a lack of methods and devices for measuring the volume of gas and electrolyte vapor generated during battery thermal runaway under normal pressure conditions. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a method and device for measuring battery thermal runaway gas production and electrolyte vapor volume at normal pressure.

[0005] According to an embodiment of the present invention, a first solution is provided:

[0006] A device for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions.

[0007] It includes a carrying device, a conveying device and a collecting and measuring device;

[0008] The carrying device comprises a frame and a fastening device;

[0009] The frame is a support frame that carries the test piece and supports the conveying device and the collecting and measuring device;

[0010] The support frame includes a base, which is used to place the test piece and the fastening device; the base provides a stable support foundation for the test piece.

[0011] The fastening device comprises a screw, a pressing plate and an air collecting port;

[0012] The screw rods are arranged on the base of the support frame, and two groups of screw rods are arranged, and a distance is arranged between the two groups of screw rods, and the distance between the two groups of screw rods is used to place the test piece;

[0013] The test piece is a battery;

[0014] The screw is connected to a pressing plate, on which a gas collecting port is arranged. The gas collecting port corresponds to the safety valve of the test piece and is sealed and connected to the test piece to prevent the gas and electrolyte vapor generated by the battery out of control from overflowing.

[0015] Furthermore, the test piece runaway includes thermal runaway and electrochemical runaway;

[0016] An initiating fixing plate is arranged on the outside of the test piece, and the function of the initiating fixing plate is to fix the test piece and provide a pre-tightening force for the test piece to prevent the test piece from deforming. At the same time, a heating device is also arranged on the side where the initiating fixing plate contacts the test piece, which is used to induce thermal runaway of the test piece.

[0017] The electrochemical runaway of the test piece is achieved by overcharging, over-discharging, high current shock, etc. of the battery.

[0018] Furthermore, the gas collecting port is connected with a gas guide pipe; the gas guide pipe is used to transmit the gas and electrolyte vapor generated by the battery runaway to the gas collecting bag;

[0019] The air pipe is provided with a heat preservation body, which is used to heat the air pipe to prevent the electrolyte vapor from condensing back into liquid; the heat preservation body uses a heating belt, infrared heating or constant temperature oil to heat the air pipe, and the temperature control is selected according to the different electrolytes of the test piece;

[0020] A solenoid valve is arranged on the air guide pipe; the air guide pipe is connected to the air collecting bag through the solenoid valve.

[0021] Further, the solenoid valve includes more than one type one solenoid valve and more than one type two solenoid valve;

[0022] The air collection bags include type I air collection bags and type II air collection bags;

[0023] The first type of solenoid valve is connected to a type of air collecting bag;

[0024] The second type of solenoid valve is connected to the second type of air collecting bag;

[0025] The first type of gas collection bag is used for collecting gas in the front and middle stages of gas production, and a large-volume gas collection bag is used; the volume is selected to be 40-100L;

[0026] The second type of gas collection bag is used for gas collection in the latter stage of gas production, and a small volume gas collection bag is used; the volume is selected to be 10-20L;

[0027] The total volume of the gas collection bag is greater than the maximum volume of gas that can be produced under the condition of loss of control of the test piece.

[0028] Furthermore, three types of solenoid valves are provided at the end of the air guide pipe; the three types of solenoid valves are connected to an exhaust device. When the volume of the gas collection bag selected for the test is insufficient, or only the gas at the front end or the front middle section or only the gas at the rear section needs to be collected, the three types of solenoid valves and the exhaust device are opened when the gas is not collected, and the waste gas is discharged to the waste gas treatment device for absorption and harmless treatment;

[0029] A heating body is arranged outside the air collecting bag, and the heating body is a heating plate or a heating film, and the heating film is directly formed integrally with the air collecting bag;

[0030] The heating body is used to heat and keep the gas collecting bag warm, so as to keep the temperature of the gas in the gas collecting bag within the set value range;

[0031] A temperature measuring device and a pressure measuring device are arranged inside the air collecting bag; both the temperature measuring device and the pressure measuring device are connected to the central controller;

[0032] The temperature measuring device uses a thermocouple;

[0033] The pressure measuring device adopts a pressure sensor;

[0034] The temperature measuring device and the heating body arranged on each air collecting bag are connected to the central controller in a group. The heating body compares the feedback from the temperature measuring device with the preset temperature, and then takes corresponding control to heat or stop heating the air collecting bag.

[0035] Furthermore, the solenoid valves are all connected to a central controller, and all the solenoid valves are in a closed state before the measuring device is started.

[0036] According to an embodiment of the present invention, using the device for measuring the gas production during thermal runaway of the battery and the electrolyte vapor volume under normal pressure conditions in the first embodiment provided by the present invention, a second embodiment is provided:

[0037] A method for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions.

[0038] S1, connect the air bag to the solenoid valve;

[0039] S2, place the test piece into the fixture, install the gas collection device, and keep it sealed with the test piece;

[0040] S3, heating and keeping the air guide tube and the air collecting bag at a constant temperature;

[0041] S4, causing battery runaway, which is caused by charging or heating;

[0042] S5, after the battery is out of control, the solenoid valves are opened in sequence to collect gas and electro-liquid vapor;

[0043] S6, calculate the total volume of gas produced and ejected electrolyte vapor under battery runaway conditions.

[0044] Furthermore, a heat preservation body is provided on the air guide pipe, and the heat preservation body is used to heat the air guide pipe, and the temperature is selected based on preventing the electrolyte vapor from condensing back into liquid;

[0045] The temperature of the heater on the air collection bag is set to simulate the temperature in an out-of-control environment.

[0046] Furthermore, the control of opening the solenoid valve is:

[0047] When the test device is started and causes thermal runaway or electrical runaway of the test piece, one of the first-class solenoid valves is opened, and the corresponding first-class gas collection bag collects the gas and electro-liquid vapor after the runaway. When the test value of the pressure measuring device of the gas collection bag reaches the preset threshold, the solenoid valve corresponding to the first-class gas collection bag is closed, and the next first-class solenoid valve is opened to collect gas;

[0048] When the volume of gas collected by the first-class gas collecting bag reaches 80% of the predicted gas production volume of the test piece when it is out of control, the first-class solenoid valve is closed and the second-class solenoid valve is opened at the same time to use the second-class gas collecting bag to collect gas; the opening control of the second-class gas collecting bag is the same as that of the first-class gas collecting bag. When one second-class gas collecting bag reaches the rated pressure, the next one is opened. The rated pressure is the pressure when the gas collecting bag is full and reaches the rated volume.

[0049] Furthermore, the method for calculating the total volume of gas produced and electrolyte vapor ejected under the condition of battery runaway is:

[0050] When the second type of gas collecting bag that was started last did not reach the rated pressure at the end of the experiment, the temperature of the gas collecting bag was increased to make the pressure of the gas collecting bag reach the rated pressure. At this time, the gas and electrolyte vapor in the gas collecting bag reached the rated volume of the gas collecting bag.

[0051] The volume of the gas in the air bag at the set temperature is calculated using the ideal gas equation PV=nRT.

[0052] The volume of all gas collection bags at the set temperature is calculated to obtain the total volume of gas produced and electrolyte vapor ejected under battery runaway conditions.

[0053] Compared with the prior art, the technical solution provided by this application has unique beneficial effects.

[0054] Compared with the existing technology, the contribution made is that it realizes the measurement and analysis of gas and electrolyte vapor generated in the battery out of control state under normal pressure conditions, which is more consistent with the actual fire accidents caused by battery thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0056] in:

[0057] Figure 1 It is a three-dimensional structural diagram of a device for measuring gas generation during thermal runaway of a battery and electrolyte vapor volume and normal pressure in one embodiment;

[0058] Figure 2 A side view of a device for measuring gas generation during thermal runaway of a battery and electrolyte vapor volume and atmospheric pressure in one embodiment;

[0059] Figure 3 It is a schematic diagram of a device for measuring gas generation during thermal runaway of a battery and electrolyte vapor volume and atmospheric pressure in one embodiment;

[0060] Figure 4 A flow chart of a method for measuring gas generation during thermal runaway of a battery and electrolyte vapor volume at normal pressure in one embodiment;

[0061] Reference numerals:

[0062] 1. Frame; 2. Fastening device; 2-1. Screw; 2-2. Pressing plate; 2-3. Gas collecting port; 3. Trigger fixing plate; 4. Test piece; 5. Air guide tube; 6. Insulating body; 7. Class I solenoid valve; 8. Class II solenoid valve; 9. Class III solenoid valve; 10. Class I gas collecting bag; 11. Class II gas collecting bag; 12. Temperature measuring device; 13. Pressure measuring device; 14. Heating body. DETAILED DESCRIPTION

[0063] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of this application.

[0064] The specific implementation scheme of the present application will be described in detail.

[0065] A device for measuring battery thermal runaway gas production and electrolyte vapor volume under normal pressure conditions, comprising a carrying device, a conveying device and a collecting and measuring device;

[0066] The carrying device comprises a frame 1 and a fastening device 2;

[0067] The frame 1 is a support frame, carrying the test piece 4 and supporting the conveying device and the collecting and measuring device;

[0068] The support frame includes a base, which is used to place the test piece 4 and the fastening device 2; the base provides a stable supporting foundation for the test piece 4.

[0069] The fastening device 2 comprises a screw 2-1, a pressing plate 2-2 and a gas collecting port 2-3;

[0070] The screw rods 2-1 are arranged on the base of the support frame, and two groups of the screw rods 2-1 are arranged, and a distance is arranged between the two groups of the screw rods 2-1, and the distance between the two groups of the screw rods 2-1 is used to place the test piece 4;

[0071] The test piece 4 is a battery;

[0072] The screw 2-1 is connected to a pressing plate 2-2, and a gas collecting port 2-3 is provided on the pressing plate 2-2. The gas collecting port 2-3 corresponds to the safety valve of the test piece 4 and can be sealed and connected to the test piece 4 to prevent the gas and electrolyte vapor generated by the battery out of control from overflowing.

[0073] The runaway of test piece 4 includes thermal runaway and electrochemical runaway.

[0074] An initiating fixing plate 3 is arranged on the outer side of the test piece 4. The initiating fixing plate 3 is used to fix the test piece 4 and provide a pre-tightening force for the test piece 4 to prevent the test piece 4 from deforming. At the same time, a heating device is also arranged on the side where the initiating fixing plate 3 contacts the test piece 4 to induce thermal runaway of the test piece 4.

[0075] The electrochemical runaway of the test piece 4 is achieved by overcharging, overdischarging, high current shock, etc. of the battery.

[0076] The gas collecting port 2-3 is connected with a gas guide pipe 5; the gas guide pipe 5 is used to transmit the gas and electrolyte vapor generated by the battery out of control to the gas collecting bag;

[0077] An insulation body 6 is provided on the air duct 5, and the insulation body 6 is used to heat the air duct 5 to prevent the electrolyte vapor from condensing back into liquid; the insulation body 6 can use a heating belt, infrared heating or constant temperature oil to insulate and heat the air duct 5, and the temperature control is selected according to the different electrolytes of the test piece 4. For example, the electrolyte of the lithium-ion battery can be 80°C.

[0078] A solenoid valve is provided on the air guide pipe 5; the air guide pipe 5 is connected to the air collecting bag through the solenoid valve;

[0079] The solenoid valve includes at least one first-class solenoid valve 7 and at least one second-class solenoid valve 8;

[0080] The air collecting bag includes a first type of air collecting bag 10 and a second type of air collecting bag 11;

[0081] The first type of solenoid valve 7 is connected to a first type of air collecting bag 10;

[0082] The second type of solenoid valve 8 is connected to a second type of air collecting bag 11;

[0083] The first type of gas collection bag 10 is used for collecting gas in the front and middle stages of gas production, and a large-volume gas collection bag is used; the volume is selected to be 40-100L;

[0084] The second type of gas collecting bag 11 is used for collecting gas in the latter stage of gas production, and adopts a small volume gas collecting bag; the volume is selected to be 10-20L.

[0085] The total volume of the gas collection bag is greater than the maximum volume of gas that can be produced under the uncontrolled condition of the test piece 4. The general calculation method is that each ampere-hour of the test piece 4 corresponds to 200L of gas production and electrolyte vapor volume.

[0086] The end of the air guide pipe 5 is provided with three types of solenoid valves 9; the three types of solenoid valves 9 are connected to an exhaust device. When the volume of the gas collecting bag selected for the test is insufficient, or only the gas from the front end or the front middle section or only the gas from the rear section needs to be collected, the three types of solenoid valves 9 and the exhaust device can be opened when the gas is not collected, and the exhaust gas can be discharged to the exhaust gas treatment device for absorption and harmless treatment.

[0087] The gas collecting bag is provided with a heater 14 outside, which can be a heating plate or a heating film, and the heating film can be directly formed integrally with the gas collecting bag. The heater 14 is used to heat and keep the gas collecting bag warm, and to keep the temperature of the gas in the gas collecting bag within a set value range.

[0088] A temperature measuring device 12 and a pressure measuring device 13 are provided inside the air collecting bag; both the temperature measuring device 12 and the pressure measuring device 13 are connected to the central controller;

[0089] The temperature measuring device 12 may be a thermocouple;

[0090] The pressure measuring device 13 may be a pressure sensor;

[0091] The temperature measuring device 12 and the heating body 14 arranged on each air collecting bag are connected to the central controller in a group. The heating body 14 compares the feedback from the temperature measuring device 12 with the preset temperature, and then takes corresponding control to heat or stop heating the air collecting bag. This part of the control is existing technology and will not be repeated here.

[0092] The solenoid valves are all connected to the central controller, and all the solenoid valves are in a closed state before the measuring device is started.

[0093] The following is an example of collecting the gas produced during the entire process.

[0094] When the test device is started to cause thermal runaway or electrical runaway of the test piece 4, one of the first-class solenoid valves 7 is opened, and the corresponding first-class gas collection bag 10 collects the gas and electro-liquid vapor after the runaway. When the test value of the pressure measuring device 13 of the gas collection bag reaches the preset threshold, the solenoid valve corresponding to the first-class gas collection bag 10 is closed, and the next first-class solenoid valve 7 is opened to collect gas.

[0095] When the volume of gas collected by the first-class gas collection bag 10 reaches 80% of the predicted gas production volume of the test piece 4 when it is out of control, the first-class solenoid valve 7 is closed, and the second-class solenoid valve 8 is opened to collect gas using the second-class gas collection bag 11. The opening control of the second-class gas collection bag 11 is the same as that of the first-class gas collection bag 10. When one second-class gas collection bag 11 reaches the rated pressure, the next one is opened. The rated pressure is the pressure when the gas collection bag is full and reaches the rated volume.

[0096] When the second type of gas collecting bag 11 that was started last did not reach the rated pressure at the end of the experiment, the temperature of the gas collecting bag was increased to make the pressure of the gas collecting bag reach the rated pressure. At this time, the gas and electrolyte vapor in the gas collecting bag reached the rated volume of the gas collecting bag.

[0097] The volume of the gas in the air bag at a set temperature can be calculated using the ideal gas equation PV=nRT.

[0098] By calculating the volume of all gas collection bags at the set temperature, the total volume of gas produced and electrolyte vapor ejected under battery out-of-control conditions can be obtained.

[0099] A method for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure using the above device,

[0100] S1, connect the air bag to the solenoid valve;

[0101] S2, place the test piece into the fixture, install the gas collection device, and keep it sealed with the test piece;

[0102] S3, heating and keeping the air guide tube and the air collecting bag at a constant temperature;

[0103] The air guide pipe is provided with a heat preservation body, which is used to heat the air guide pipe. The temperature is selected based on preventing the electrolyte vapor from condensing back into liquid.

[0104] The temperature of the heater on the air collection bag is set to simulate the temperature in an out-of-control environment.

[0105] S4, causing battery runaway, which is caused by charging or heating;

[0106] S5, after the battery is out of control, the solenoid valves are opened in sequence to collect gas and electro-liquid vapor;

[0107] The control of the solenoid valve opening is:

[0108] When the test device is started and causes thermal runaway or electrical runaway of the test piece, one of the first-class solenoid valves is opened, and the corresponding first-class gas collection bag collects the gas and electro-liquid vapor after the runaway. When the test value of the pressure measuring device of the gas collection bag reaches the preset threshold, the solenoid valve corresponding to the first-class gas collection bag is closed, and the next first-class solenoid valve is opened to collect gas;

[0109] When the volume of gas collected by the first-class gas collection bag reaches 80% of the predicted gas production volume of the test piece when it is out of control, the first-class solenoid valve is closed, and the second-class solenoid valve is opened at the same time to use the second-class gas collection bag to collect gas. The opening control of the second-class gas collection bag is the same as that of the first-class gas collection bag. When one second-class gas collection bag reaches the rated pressure, the next one is opened. The rated pressure is the pressure when the gas collection bag is filled to the rated volume.

[0110] S6, calculate the total volume of gas produced and ejected electrolyte vapor under battery runaway conditions.

[0111] When the second type of gas collecting bag that was started last did not reach the rated pressure at the end of the experiment, the temperature of the gas collecting bag was increased to make the pressure of the gas collecting bag reach the rated pressure. At this time, the gas and electrolyte vapor in the gas collecting bag reached the rated volume of the gas collecting bag.

[0112] The volume of the gas in the air bag at a set temperature can be calculated using the ideal gas equation PV=nRT.

[0113] By calculating the volume of all gas collection bags at the set temperature, the total volume of gas produced and electrolyte vapor ejected under battery out-of-control conditions can be obtained.

[0114] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0115] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0116] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A device for measuring battery thermal runaway gas production and electrolyte vapor volume under normal pressure conditions, characterized in that: It includes a carrying device, a conveying device and a collecting and measuring device; The carrying device comprises a frame and a fastening device; The frame is a support frame that carries the test piece and supports the conveying device and the collecting and measuring device; The support frame includes a base, which is used to place the test piece and the fastening device; The base provides a stable support for the test piece. The fastening device comprises a screw, a pressing plate and an air collecting port; The screw rods are arranged on the base of the support frame, and two groups of screw rods are arranged, and a distance is arranged between the two groups of screw rods, and the distance between the two groups of screw rods is used to place the test piece; The test piece is a battery; The screw is connected to a pressing plate, on which a gas collecting port is arranged. The gas collecting port corresponds to the safety valve of the test piece and is sealed and connected to the test piece to prevent the gas and electrolyte vapor generated by the battery out of control from overflowing.

2. The device for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 1, characterized in that: Test piece runaway includes thermal runaway and electrochemical runaway; An initiating fixing plate is arranged on the outside of the test piece, and the function of the initiating fixing plate is to fix the test piece and provide a pre-tightening force for the test piece to prevent the test piece from deforming. At the same time, a heating device is also arranged on the side where the initiating fixing plate contacts the test piece, which is used to induce thermal runaway of the test piece. The electrochemical runaway of the test piece is achieved by overcharging, over-discharging, high current shock, etc. of the battery.

3. The device for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 2, characterized in that: The gas collecting port is connected with a gas guide pipe; the gas guide pipe is used to transmit the gas and electrolyte vapor generated by the battery out of control to the gas collecting bag; The air pipe is provided with a heat preservation body, which is used to heat the air pipe to prevent the electrolyte vapor from condensing back into liquid; the heat preservation body uses a heating belt, infrared heating or constant temperature oil to heat the air pipe, and the temperature control is selected according to the different electrolytes of the test piece; A solenoid valve is arranged on the air guide pipe; the air guide pipe is connected to the air collecting bag through the solenoid valve.

4. The device for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 3, characterized in that: The solenoid valve includes more than one first-class solenoid valve and more than one second-class solenoid valve; The air collection bags include type I air collection bags and type II air collection bags; The first type of solenoid valve is connected to a type of air collecting bag; The second type of solenoid valve is connected to the second type of air collecting bag; The first type of gas collection bag is used for collecting gas in the front and middle stages of gas production, and a large-volume gas collection bag is used; the volume is selected to be 40-100L; The second type of gas collection bag is used for gas collection in the latter stage of gas production, and a small volume gas collection bag is used; the volume is selected to be 10-20L; The total volume of the gas collection bag is greater than the maximum volume of gas that can be produced under the condition of loss of control of the test piece.

5. The device for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 4, characterized in that: The end of the air guide pipe is provided with three types of solenoid valves; the three types of solenoid valves are connected to an exhaust device. When the volume of the gas collection bag selected for the test is insufficient, or only the gas at the front end or the front middle section or only the gas at the rear section needs to be collected, the three types of solenoid valves and the exhaust device are opened when the gas is not collected, and the waste gas is discharged to the waste gas treatment device for absorption and harmless treatment; A heating body is arranged outside the air collecting bag, and the heating body is a heating plate or a heating film, and the heating film is directly formed integrally with the air collecting bag; The heating body is used to heat and keep the gas collecting bag warm, so as to keep the temperature of the gas in the gas collecting bag within the set value range; A temperature measuring device and a pressure measuring device are arranged inside the air collecting bag; both the temperature measuring device and the pressure measuring device are connected to the central controller; The temperature measuring device uses a thermocouple; The pressure measuring device adopts a pressure sensor; The temperature measuring device and the heating body arranged on each air collecting bag are connected to the central controller in a group. The heating body compares the feedback from the temperature measuring device with the preset temperature, and then takes corresponding control to heat or stop heating the air collecting bag.

6. The device for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 5, characterized in that: The solenoid valves are all connected to the central controller, and all the solenoid valves are in a closed state before the measuring device is started.

7. A method for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions, characterized in that: S1, connect the air bag to the solenoid valve; S2, place the test piece into the fixture, install the gas collection device, and keep it sealed with the test piece; S3, heating and keeping the air guide tube and the air collecting bag at a constant temperature; S4, causing battery runaway, which is caused by charging or heating; S5, after the battery is out of control, the solenoid valves are opened in sequence to collect gas and electro-liquid vapor; S6, calculate the total volume of gas produced and ejected electrolyte vapor under battery runaway conditions.

8. The method for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 7, characterized in that: The air guide pipe is provided with a heat preservation body, which is used to heat the air guide pipe. The temperature is selected based on preventing the electrolyte vapor from condensing back into liquid. The temperature of the heater on the air collection bag is set to simulate the temperature in an out-of-control environment.

9. The method for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 8, characterized in that: The control of the solenoid valve opening is: When the test device is started and causes thermal runaway or electrical runaway of the test piece, one of the first-class solenoid valves is opened, and the corresponding first-class gas collection bag collects the gas and electro-liquid vapor after the runaway. When the test value of the pressure measuring device of the gas collection bag reaches the preset threshold, the solenoid valve corresponding to the first-class gas collection bag is closed, and the next first-class solenoid valve is opened to collect gas; When the volume of gas collected by the first-class gas collecting bag reaches 80% of the predicted gas production volume of the test piece when it is out of control, the first-class solenoid valve is closed and the second-class solenoid valve is opened at the same time to use the second-class gas collecting bag to collect gas; the opening control of the second-class gas collecting bag is the same as that of the first-class gas collecting bag. When one second-class gas collecting bag reaches the rated pressure, the next one is opened. The rated pressure is the pressure when the gas collecting bag is full and reaches the rated volume.

10. The method for measuring battery thermal runaway gas generation and electrolyte vapor volume under normal pressure conditions according to claim 9, characterized in that: The method for calculating the total volume of gas produced and electrolyte vapor ejected under battery runaway conditions is: When the second type of gas collecting bag that was started last did not reach the rated pressure at the end of the experiment, the temperature of the gas collecting bag was increased to make the pressure of the gas collecting bag reach the rated pressure. At this time, the gas and electrolyte vapor in the gas collecting bag reached the rated volume of the gas collecting bag. The volume of the gas in the air bag at the set temperature is calculated using the ideal gas equation PV=nRT. The volume of all gas collection bags at the set temperature is calculated to obtain the total volume of gas produced and electrolyte vapor ejected under battery runaway conditions.

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