Device for in-situ detection of interface gas production reaction in heating process of battery material

Abstract

The utility model belongs to the field of battery material detection, and particularly relates to a device for in-situ detection of interface gas production reaction in the heating process of a battery material, which comprises a carrier gas unit, a sample heating unit, a cooling unit and a gas collecting and analyzing unit. The carrier gas unit can also control the flow of gas entering the pipeline; the sample heating unit can heat the sample by adopting different temperature rising programs; the condensable liquid is cooled through a cooling unit, and gas is separated; and the collected gas can be qualitatively and quantitatively analyzed in the gas collection and analysis unit. The device disclosed by the utility model can conveniently collect and analyze the gas generated in the heating process after the battery materials are independent or mixed; the type of the generated gas can correspond to the temperature, and the reaction path and the decomposition product in the heating process of the battery material can be understood from a deeper level, so that the safety working limit of the battery is determined, and the thermal runaway risk of the battery during use is avoided.

Description

Technical Field

[0001] The utility model belongs to the field of battery material detection, and particularly relates to a device for in-situ detecting the interfacial gas generation reaction during the heating process of battery materials. Background Art

[0002] Since the 21st century, in order to protect the ecological environment and address the increasingly severe climate issues, countries have actively carried out the development and application of clean energy. Secondary batteries are widely used in small electronic devices, electric vehicles, and large-scale energy storage systems due to their high energy density, low cost, long life, etc. In recent years, the rapid development of consumer electronics and electric vehicles has put forward higher requirements for the energy density of lithium-ion batteries. However, with the increase in battery energy density, the thermal stability of battery materials and the thermal compatibility between materials will also decrease, thus triggering battery safety problems. Recently, frequent thermal runaway accidents such as battery smoking, catching fire, and even exploding have greatly hit the market confidence in the commercialization of the new energy industry. Battery thermal runaway is usually caused by overheating of the battery system. The irreversible heat during the battery cycle continuously accumulates, increasing the temperature inside the battery and inducing a series of side reactions, such as SEI decomposition, the reaction between the electrode and the electrolyte, diaphragm shrinkage, positive electrode phase change, etc. The heat generated by the side reactions rapidly increases the temperature of the battery system. A series of chain reactions also occur, leading to the complete thermal runaway of the battery. During the self-heating process of the battery, the gas generation behavior inside the battery is of great significance to the development of the entire heat release chain. Therefore, analyzing the gas generation behavior of the battery, especially the internal materials of the battery, during the heating process has important guiding significance for deeply understanding the battery thermal runaway mechanism and the subsequent design and development of high-safety battery systems.

[0003] Currently, for the gas test during the battery heating process, mainly the gas generated by the battery is collected during heating, and then the gas content, components, etc. are analyzed by connecting a gas chromatograph or a mass spectrometer. This method cannot detect the gas in real time during the heating process, nor can it analyze the reactions between different gases at different temperatures. It can only detect the final gas products. By using equipment such as a thermogravimetry-mass spectrometer (TGA-MS) in combination, the heat release and gas generation of the battery cannot be effectively correlated, and it is not applicable to a mixed system of battery materials with intense chemical reactions with each other or electrode materials with strong corrosiveness. In summary, the existing technology cannot achieve in-situ gas detection during the heating process for materials with reactive activities with each other inside the battery. Summary of the Utility Model

[0004] Aiming at the problems in the prior art that there are no analysis means for highly reactive and highly corrosive materials, no real-time detection, and inaccurate analysis of gas production components, the purpose of the present utility model is to provide a device for in-situ detecting the interfacial gas production reaction during the heating process of battery materials. This device can synchronously analyze the exothermic process of battery materials with high reactivity and their corresponding gas production behaviors, and can provide more accurate and real-time information on the gas production components and contents during the heating process of battery materials, providing an important reference and reliable basis for battery material research.

[0005] The purpose of the present utility model is achieved through the following technical solutions:

[0006] The present utility model includes a carrier gas unit, a sample heating unit, a cooling unit, and a gas collection and analysis unit. The cooling unit includes a reflux liquid collection bottle, a serpentine pipeline, and a cold trap. The gas collection and analysis unit includes an exhaust pipeline, a mass spectrometer, and a computer. One end of the serpentine pipeline is connected to the sample heating unit, which is the place for sample heating and gas generation, through connection pipeline A. The carrier gas unit is connected to connection pipeline A. The other end of the serpentine pipeline is connected to the inlet of the cold trap. The outlet of the cold trap is connected to the mass spectrometer through connection pipeline B. The mass spectrometer is connected to the computer. An exhaust pipeline communicating with the external environment is connected to connection pipeline B; a reflux liquid collection bottle is connected to the serpentine pipeline.

[0007] Among them: a three-way A is provided on connection pipeline A. The carrier gas unit includes a gas cylinder. The sample heating unit includes an ARC device and a straight-through particle filter. The first interface of the three-way A is connected to the ARC device through a pipeline, and a straight-through particle filter is provided on the pipeline between the ARC device and the three-way A. The second interface of the three-way A is connected to the gas cylinder through a pipeline. The third interface of the three-way A is connected to the first interface of a three-way C. The second interface of the three-way C is connected to the reflux liquid collection bottle. The third interface of the three-way C is connected to one end of the serpentine pipeline.

[0008] A micro-regulating valve is provided on the pipeline between the straight-through particle filter and the three-way A.

[0009] A flow meter is provided on the pipeline between the gas cylinder and the three-way A, and the flow meter is connected to the computer.

[0010] The gas type in the gas cylinder is one or more of oxygen, nitrogen, argon, carbon monoxide, and air.

[0011] A U-shaped tube is provided in the cold trap, and both ends of the U-shaped tube are respectively connected to the other end of the serpentine pipeline and connection pipeline B.

[0012] The positions of the two sides of the U-shaped tube close to the U-shaped opening are connected and communicated through an air pipeline.

[0013] A tee joint B is provided on the connecting pipeline B. The first interface of the tee joint B is connected to the outlet of the cold trap, the second interface of the tee joint B is connected to the exhaust pipeline, and the third interface of the tee joint B is connected to the mass spectrometer.

[0014] The cold trap is filled with dry ice or liquid nitrogen for cooling.

[0015] The connecting pipeline A, the connecting pipeline B and the pipelines for connection in the device are all 1 / 8 stainless steel pipes.

[0016] The advantages and positive effects of the present utility model are as follows:

[0017] 1. The present utility model can synchronously detect the exothermic characteristics of battery materials and the gas components generated during the heating process in one experiment.

[0018] 2. The upper limit of the experimental sample amount that can be used in the present utility model is higher (<20 g), greatly reducing the accidental error caused by too little sample amount and greatly improving the accuracy of detection.

[0019] 3. The present utility model can test two battery materials that are reactive at high temperatures and corrosive battery materials, expanding the types of samples that can be tested.

[0020] 4. By analyzing the gas generation behavior and reaction mechanism in lithium-ion batteries, the present utility model provides guidance for improving the safety of lithium-ion batteries and understanding the internal reaction mechanism of batteries at high temperatures. Description of the Drawings

[0021] Figure 1 is the overall structural schematic diagram of the present utility model;

[0022] Figure 2 is the gas flow rate - temperature curve diagram of a single negative electrode material in an argon atmosphere with a constant heating rate program in Experimental Example 1 of the present utility model;

[0023] Figure 3 is the gas flow rate - temperature curve diagram of the mixed material of the negative electrode material and the electrolyte in an argon atmosphere with a rapid heating mode in Experimental Example 2 of the present utility model;

[0024] Figure 4 is the gas flow rate - temperature curve diagram of a single negative electrode material in an argon atmosphere with a "heating - waiting - searching" heating program in Experimental Example 3 of the present utility model;

[0025] Wherein: 1 is a gas cylinder, 2 is a flowmeter, 3 is an ARC device, 4 is a straight-through particle filter, 5 is a micro regulating valve, 6 is a reflux liquid collection bottle, 7 is a serpentine pipeline, 8 is a cold trap, 9 is a U-shaped tube, 10 is an exhaust pipeline, 11 is a mass spectrometer, 12 is a desktop computer, 13 is an air pipeline, 14 is a three-way A, 15 is a three-way B, and 16 is a three-way C. Specific embodiments

[0026] The present utility model will be further described in detail below with reference to the accompanying drawings.

[0027] As Figure 1 shown, the present utility model includes a carrier gas unit, a sample heating unit, a cooling unit, and a gas collection and analysis unit.

[0028] The cooling unit of this embodiment can ensure that the condensable liquid is sufficiently cooled, thereby improving the accuracy of the detection of the present utility model and preventing damage and contamination to the gas collection and analysis unit; the cooling unit includes a reflux liquid collection bottle 6, a serpentine pipeline 7, and a cold trap 8, and the gas collection and analysis unit includes an exhaust pipeline 10, a mass spectrometer 11, and a computer. One end of the serpentine pipeline 7 is connected to the sample heating unit, which is the place for sample heating and gas generation, through a connecting pipeline A, and the carrier gas unit is connected to the connecting pipeline A. The other end of the serpentine pipeline 7 is connected to the inlet of the cold trap 8, the outlet of the cold trap 8 is connected to the mass spectrometer 11 through a connecting pipeline B, the mass spectrometer 11 is connected to the computer, and an exhaust pipeline 10 communicating with the external environment is connected to the connecting pipeline B; a reflux liquid collection bottle 6 is connected to the serpentine pipeline 7.

[0029] The carrier gas unit of this embodiment includes a gas cylinder 1, a flowmeter 2, and a gas regulating pressure reducing valve connected to the outlet of the gas cylinder 1. The flowmeter 2 is a prior art. The working pressure of the flowmeter 2 in this embodiment is 0 - 50 MPa, and the flow display range is 0 - 10 mL / min. The carrier gas unit is used to control the gas flow rate and gas type in the pipeline and prevent external gases from interfering with the test process. The gas type in the gas cylinder 1 is one or more of oxygen, nitrogen, argon, carbon monoxide, and air.

[0030] The sample heating unit of this embodiment mainly serves as the main site where the electrode material reacts and is also the unit that generates the gas to be measured. The sample heating unit includes an ARC device 3, a straight-through particle filter 4, and a micro-regulating valve 5. A tee A14 is provided on the connecting pipeline A. The first interface of the tee A14 is connected to the ARC device 3 through a pipeline, and a straight-through particle filter 4 is provided on the pipeline between the ARC device 3 and the tee A14. A micro-regulating valve 5 is provided on the pipeline between the straight-through particle filter 4 and the tee A14. The second interface of the tee A14 is connected to the gas cylinder 1 through a pipeline. The flowmeter 2 is provided on the pipeline between the gas cylinder 1 and the second interface of the tee A14, and the flowmeter 2 is connected to the computer. The third interface of the tee A14 is connected to the first interface of the tee C16. The second interface of the tee C16 is connected to the reflux liquid collection bottle 6. The third interface of the tee C16 is connected to one end of the serpentine pipeline 7. The ARC device 3, the straight-through particle filter 4, and the micro-regulating valve 5 of this embodiment are all commercially available products. The ARC device 3 is purchased from HEL Company in the UK, with the model BTC-130. The straight-through particle filter 4 is purchased from the straight-through filter of the particle filter produced by Swagelok Company in the United States. The micro-regulating valve 5 is purchased from the 34S series medium-aperture regulating valve produced by Beijing Xiongchuan Valve Manufacturing Co., Ltd.

[0031] The ARC device 3 can operate the sample in multiple heating modes, including isothermal heating, constant temperature testing, and heating-waiting-search mode, etc. In the heating-waiting-search mode, when it is detected that the sample self-heats, the ARC device 3 no longer actively heats the sample, simulating that the sample is in an adiabatic environment. A temperature sensor can be placed in the heating sample chamber to detect the sample temperature in real time. In addition, a pressure sensor is built into the ARC device to track the pressure change during the heating process and monitor the airtightness of the device during the test. The ARC device 3 can withstand a maximum pressure of 150 MPa to ensure that the ARC device 3 can withstand the short-term rapid gas generation during the chemical reaction. The main material of the heating sample chamber in the ARC device 3 is C-276 Hastelloy, which makes the heating sample chamber have excellent corrosion resistance and expands the range of battery materials that can be tested.

[0032] The straight-through particle filter 4 can use different filter element specifications, including but not limited to 7 microns, 15 microns, 40 microns, 60 microns, and 90 microns, which can effectively remove the solid particles mixed in the gas generated by the ARC device 3, ensure the smoothness of the subsequent pipeline and the accuracy of the test gas. The operating temperature of the straight-through particle filter 4 is -20°C to 482°C.

[0033] The micro-regulating valve 5 is equipped with a vernier scale handle, which can realize precise adjustment of the pipeline flow; the working pressure of the micro-regulating valve 5 is 0-20MPa, which can ensure the high-pressure environment in the heating sample chamber and eliminate the influence of pressure reduction on the reaction in the heating sample chamber.

[0034] The cold trap 8 of this embodiment is provided with a U-shaped tube 9, and the two ends of the U-shaped tube 9 are respectively connected to the other end of the serpentine pipeline 7 and the connecting pipeline B; the cold trap 8 selects appropriate filling materials according to different reaction raw materials and different reaction heat releases to prevent liquid from moving to the gas collection and analysis unit, thereby improving the gas detection accuracy; the cold trap 8 of this embodiment is filled with dry ice or liquid nitrogen for cooling. The positions near the U-shaped opening on both sides of the U-shaped tube 9 are connected through the gas pipeline 13 to prevent the condensed liquid from gathering at the bottom of the U-shaped tube 9 and hindering the smoothness of the pipeline gas flow.

[0035] A tee B15 is provided on the connecting pipeline B of this embodiment, a first interface of the tee B15 is connected to the outlet of the cold trap 8, a second interface of the tee B15 is connected to the exhaust pipeline 10, and a third interface of the tee B15 is connected to the mass spectrometer 11.

[0036] The gas collection and analysis unit can realize synchronous analysis and record storage of the gas to be tested generated by the sample heating unit. The mass spectrometer 11 of this embodiment is a prior art, including a quadrupole mass spectrometer, a molecular pump and a diaphragm pump. The scanning range of the quadrupole mass spectrometer is 1u~100u, which covers almost all gases that may be generated by battery reactions. It can be used to detect gas components in the heating process of various systems, including lithium-ion batteries, lithium metal batteries and sodium-ion batteries. Before using the quadrupole mass spectrometer, the molecular pump and the diaphragm pump must be turned on in turn, and the vacuum degree inside the mass spectrometer 11 must be pumped to 5×10 -4 The computer of this embodiment is a desktop computer 12, and the flow meter 2, the temperature sensor and the pressure sensor in the ARC device 3 are respectively connected to the desktop computer 12. The flow rate range of the flow meter 2 can be changed by computer control. During the test, the flow meter is set to a constant flow rate to ensure that the airflow is stable and the baseline is flat during the test, which helps to obtain reliable test data.

[0037] The connecting pipeline A, the connecting pipeline B and the pipelines used for connection in the device of this embodiment are all 1 / 8 stainless steel pipes.

[0038] The working principle of the utility model is:

[0039] The sample is heated in the heating sample chamber of the ARC device 3 according to a set program and reacts to generate gas. Since the pressure in the heating sample chamber increases, the solids in the sample will be carried into the pipeline together. The straight-through particle filter 4 can filter out the solid particles, and the filter element of the straight-through particle filter 4 is selected according to different solid particle sizes; the gas filtered from the solids then passes through the micro-regulating valve 5 and enters the cooling unit together with the carrier gas provided by the gas cylinder 1 passing through the flowmeter 2.

[0040] The mixed gas passes through a long serpentine pipeline 7. The serpentine pipeline 7 is air-cooled. Some high-boiling-point (greater than 60 °C) condensate liquids condense into liquids in the serpentine pipeline 7 and slowly flow into the reflux liquid collection bottle 6; the gas enters the U-shaped tube 9 for deep condensation. The U-shaped tube 9 is placed in a cold trap 8 filled with liquid nitrogen or dry ice. For different components, the filling in the cold trap 8 will be changed; low-boiling-point (less than 60 °C) liquids will accumulate at the bottom of the U-shaped tube 9, and the gas flows through the gas pipeline 13 in the middle of the U-shaped tube 9.

[0041] The gas flowing out of the U-shaped tube 9 will discharge the excess gas through the exhaust pipeline 10, and the remaining gas enters the mass spectrometer 11 for detection and analysis. The obtained gas component results can be directly displayed on the desktop computer 12 and further processed. The specific steps are as follows:

[0042] Step A, before installing the sample chamber in the ARC device 3, fully open the micro-regulating valve 5, set the flow rate of the flowmeter 2 to 10 mL / min, and exhaust the air in each pipeline including the connecting pipeline A and the connecting pipeline B to fill the entire pipeline with the carrier gas;

[0043] Step B, transfer the sample chamber from the glove box to the ARC device 3;

[0044] Step C, set the flowmeter 2 to a fixed flow rate, adjust the micro-regulating valve 5 to the set position, and place the exhaust pipeline 10 in the leak detection liquid. If there are uniform bubbles emerging, it proves that the gas tightness of the pipeline is good;

[0045] Step D, if there is no problem with the airtightness of the device, set the mass-to-charge ratio (m / e) of the gas to be detected on the desktop computer 12 and turn on the mass spectrometer 11;

[0046] Step E, after the gas baseline displayed on the desktop computer 12 is stable, turn on the ARC device 3 to heat the sample.

[0047] The detection object of this embodiment can be materials of secondary batteries (including lithium-ion batteries, lithium metal batteries, lithium-sulfur batteries, sodium batteries, zinc batteries, magnesium batteries, etc.) in different charged states, including: any combination of one or more of current collectors, cathode materials, anode materials, separators, electrolytes (liquid, gel and solid), binders added to the aforementioned materials, and additives added to the aforementioned materials.

[0048] The binder can be polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR) emulsion, carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyacrylonitrile (PAN) or polyacrylate.

[0049] The additive can be:

[0050] Vinyl fluorocarbonate (FEC) has good film-forming property for SEI, and the formed SEI contains more inorganic passivation layers, improving the battery safety.

[0051] Vinylene carbonate (VC) has good high and low temperature performance and anti-gas expansion function, and is commonly used as a new organic film-forming additive and overcharge protection additive for lithium-ion batteries, which can improve the battery capacity and cycle life.

[0052] Lithium nitrate (LiNO3) can help form a strong SEI film and inhibit the shuttle of polysulfides, and is widely used as an additive in lithium-sulfur batteries.

[0053] Trimethyl phosphate (TMP) as a flame retardant can increase the flash point and flame retardant performance of the electrolyte, thus improving the battery safety performance.

[0054] In this embodiment, since some battery materials are extremely sensitive to air, especially water and oxygen in it, the preparation of battery materials is all carried out in a glove box under an argon atmosphere, and the contents of H2O and O2 in the glove box are both less than 0.01 ppm. Specifically, the lithium salt is 1 mol / L lithium hexafluorophosphate (LiPF6); the solvents are ethylene carbonate (EC) and ethyl methyl carbonate (EMC), mixed in a volume ratio of 3:7; a 1 Ah NCM811 / silicon-carbon 450 soft-pack battery assembled with the above electrolyte, where the silicon-carbon 450 is prepared by mixing 8.7% mass fraction of SiOx and 91.3% of graphite. The soft-pack battery is formed at a rate of 0.1C for 2 cycles in the voltage range of 3.0V to 4.2V and then degassed, and then the battery is charged to 4.2V at a rate of 0.1C. The battery is transferred into the glove box and disassembled, and the cathode material powder and anode material powder are scraped off with a blade for standby.

[0055] Experimental Example 1

[0056] The experimental platform was set up according to the method described in the above embodiments. In the argon glove box, 150 mg of the negative electrode powder was weighed and placed into the reaction chamber. After exhausting the air in the pipeline, it was transferred to the ARC device 3. The gas cylinder 1 was connected, the flow rate of the flowmeter 2 was set to 6 mL / min, the micro regulating valve 5 was adjusted to make the pipeline gas unobstructed, the mass spectrometer 11 was turned on to work properly, and the types of gases to be detected were set on the desktop computer 12 as the gases with mass-to-charge ratios (m / e) of 2, 16, 28, 32, and 44 respectively. When the baseline was stable, the ARC device 3 used a constant-rate heating mode to heat the sample. The heating rate was 1 °C / min, and the heating cut-off temperature was 500 °C.

[0057] As Figure 2 shown, the gas curve of the mass spectrometer 11 was combined with the temperature axis of the ARC device 3 to obtain the gas flow-temperature curve. The curve shows that the main gases during the heating process are the gases with mass-to-charge ratios of 2, 16, and 44, representing H2, CH4, and CO2 respectively. The generation temperatures of H2 and CO2 in the system are relatively early, about 100 °C. After integrating the curve with respect to time, it was found that the generation amount of H2 is the largest.

[0058] Experimental Example 2

[0059] The experimental platform was set up according to the method described in the above embodiments. In the argon glove box, 150 mg of the negative electrode powder and 0.5 mL of the electrolyte were weighed and placed into the reaction chamber. After exhausting the air in the pipeline, it was transferred to the ARC device 3. The gas cylinder 1 was connected, the flow rate of the flowmeter 2 was set to 4 mL / min, the micro regulating valve 5 was adjusted to make the pipeline gas unobstructed, the mass spectrometer 11 was turned on to work properly, and the types of gases to be detected were set on the desktop computer 12 as the gases with mass-to-charge ratios (m / e) of 2, 16, 28, 32, and 44 respectively. When the baseline was stable, the ARC device 3 used a constant-rate heating mode to heat the sample. The heating rate was 1 °C / min, and the heating cut-off temperature was 500 °C.

[0060] As Figure 3 shown, the gas curve of the mass spectrometer 11 was combined with the temperature axis of the ARC device 3 to obtain the gas flow-temperature curve. The curve shows that the main gases during the heating process are the gases with mass-to-charge ratios of 2, 16, 28, and 44, representing H2, CH4, C2H4 / CO, and CO2 respectively. The generation temperature of H2 in the system is relatively early, about 120 °C, and the generation amount of CO2 is the largest. Compared with the test of the negative electrode material in Experimental Example 1, the amount of gas produced by the battery material system after mixing with the electrolyte is more, indicating that the interfacial gas generation reaction between the negative electrode and the electrolyte is more intense after mixing.

[0061] Experimental Example 3

[0062] Set up the experimental platform according to the method described in the above embodiments. In an argon glove box, weigh 150 mg of the negative electrode powder and load it into the reaction cavity. After exhausting the air in the pipeline, transfer it to the ARC device 3, connect the gas cylinder 1, set the flow rate of the flowmeter 2 to 6 mL / min, adjust the micro regulating valve 5 to make the pipeline gas unobstructed, turn on the mass spectrometer 11 to make it work properly, and set the detected gas types on the desktop computer 12 as the gases with mass-to-charge ratios (m / e) of 2, 16, 28, 32, and 44 respectively. When the baseline is stable, perform stepwise heating on the sample using the heating-waiting-search heating mode. The test temperature range is 60 - 250 °C, the heating step is 5 °C, the waiting time is 20 min, the detection limit is 0.03 °C / min, and the maximum cut-off temperature is 500 °C.

[0063] As Figure 4 shown, combine the gas curve of the mass spectrometer 11 with the material heating curve of the ARC device 3. The gas curve shows that the main gases during the heating process are the gases with mass-to-charge ratios of 2, 16, 28, and 44, which represent H2, CH4, C2H4 / CO, and CO2 respectively. For the heating curve, the thermal runaway initiation temperature (T tr ) of this system is 221 °C. By corresponding to the gas generation temperature, it can be found that H2, CH4, C2H4 / CO, and CO2 also gradually start to be generated at this temperature ( Figure 4 dashed line in). There is a good correspondence between the temperature curve and the gas generation curve. And after integrating this curve, it is found that the generation amount of H2 is the largest. This is consistent with the test results in Experimental Example 1 under the constant heating rate mode.

[0064] An in-situ detection device for the interfacial gas generation reaction during the heating process of battery materials provided by the present utility model is mainly used to detect the gas components decomposed during the heating process of secondary battery electrode materials and the gas components generated by the reaction of different battery materials during the heating process. The present utility model can detect in real time the gas components generated by different components of battery materials during the heating process, which has an important role in studying and understanding the thermal stability and thermal runaway mechanism of battery materials.

[0065] The above description is only the implementation mode of the present utility model and is not used to limit the protection scope of the present utility model. Any modifications, equivalent replacements, improvements, expansions, etc. made within the spirit and principle of the present utility model are included in the protection scope of the present utility model.

Claims

1. An apparatus for in-situ detecting the interfacial gas generation reaction during the heating process of battery materials, characterized in that: It includes a carrier gas unit, a sample heating unit, a cooling unit, and a gas collection and analysis unit. The cooling unit includes a reflux liquid collection bottle (6), a serpentine pipeline (7), and a cold trap (8). The gas collection and analysis unit includes an exhaust pipeline (10), a mass spectrometer (11), and a computer. One end of the serpentine pipeline (7) is connected to the sample heating unit, which is the place for sample heating and gas generation, through connection pipeline A. The carrier gas unit is connected to connection pipeline A. The other end of the serpentine pipeline (7) is connected to the inlet of the cold trap (8). The outlet of the cold trap (8) is connected to the mass spectrometer (11) through connection pipeline B. The mass spectrometer (11) is connected to the computer. An exhaust pipeline (10) communicating with the external environment is connected to connection pipeline B. A reflux liquid collection bottle (6) is connected to the serpentine pipeline (7).

2. The device for in-situ detecting the interfacial gas generation reaction during the heating process of battery materials according to claim 1, characterized in that: A tee A (14) is provided on connection pipeline A. The carrier gas unit includes a gas cylinder (1). The sample heating unit includes an ARC device (3) and a straight-through particle filter (4). The first interface of the tee A (14) is connected to the ARC device (3) through a pipeline, and a straight-through particle filter (4) is provided on the pipeline between the ARC device (3) and the tee A (14). The second interface of the tee A (14) is connected to the gas cylinder (1) through a pipeline. The third interface of the tee A (14) is connected to the first interface of a tee C (16). The second interface of the tee C (16) is connected to the reflux liquid collection bottle (6). The third interface of the tee C (16) is connected to one end of the serpentine pipeline (7).

3. The device for in-situ detecting the interfacial gas generation reaction during the heating process of the battery material according to claim 2, wherein: A micro regulating valve (5) is provided on the pipeline between the straight-through particle filter (4) and the tee A (14).

4. The device for in-situ detecting the interfacial gas generation reaction during the heating process of battery materials according to claim 2, wherein: A flow meter (2) is provided on the pipeline between the gas cylinder (1) and the tee A (14), and the flow meter (2) is connected to the computer.

5. The device for in-situ detecting the interfacial gas generation reaction during the heating process of battery materials according to claim 2, characterized in that: The gas in the gas cylinder (1) is one or more of oxygen, nitrogen, argon, carbon monoxide, and air.

6. The device for in-situ detecting the interfacial gas generation reaction during the heating process of the battery material according to claim 1, wherein: A U-shaped tube (9) is provided in the cold trap (8), and both ends of the U-shaped tube (9) are respectively connected to the other end of the serpentine pipeline (7) and connection pipeline B.

7. The device for in-situ detecting the interfacial gas generation reaction during the heating process of battery materials according to claim 6, wherein: The positions of the two sides of the U-shaped tube (9) close to the U-shaped opening are connected through an air pipeline (13).

8. The device for in-situ detecting the interfacial gas generation reaction during the heating process of battery materials according to claim 1, characterized in that: A tee B (15) is provided on connection pipeline B. The first interface of the tee B (15) is connected to the outlet of the cold trap (8). The second interface of the tee B (15) is connected to the exhaust pipeline (10). The third interface of the tee B (15) is connected to the mass spectrometer (11).

9. The device for in-situ detecting the interfacial gas generation reaction during the heating process of the battery material according to claim 1, wherein: The cold trap (8) is filled with dry ice or liquid nitrogen for cooling.

10. The device for in-situ detecting the interfacial gas generation reaction during the heating process of the battery material according to claim 1, wherein: The connection pipeline A, connection pipeline B, and the pipelines for connection in the device are all 1 / 8 stainless steel pipes.

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