Testing equipment and testing method for thermal gas production of lithium battery

Abstract

The invention discloses equipment and a method for testing thermal gas production of a lithium battery, and the equipment comprises an environment box, a sample bin, a charging and discharging device, a first electromagnetic valve, a first gas guide pipeline, a gas collection device and a controller, the first gas guide pipeline is sequentially connected with the first electromagnetic valve and the gas collecting device through a first through hole of the environment box, the environment box has a heating function, and the controller is used for controlling the charging and discharging device to carry out charging and discharging control on the lithium battery, so that the gas collecting device can collect gas when the charge state of the lithium battery reaches a preset charge range. Controlling the environment box to heat according to a preset rate so as to enable the temperature in the sample bin to reach a preset temperature threshold value, controlling the first electromagnetic valve to be in an open state so as to enable the gas in the sample bin to enter the gas collecting device, and performing component analysis according to the gas collected by the gas collecting device at different temperatures, therefore, gas collection of the lithium battery under different charge states and different temperatures can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of battery safety testing, and in particular to a testing device for thermal gas generation of a lithium battery and a testing method for thermal gas generation of a lithium battery. Background Art

[0002] Lithium-ion batteries have become the core of modern energy technology due to their excellent performance. In the field of energy storage, they provide efficient energy storage solutions for renewable energy such as solar and wind energy, balance energy supply and demand, and improve the stability and reliability of the power grid. In the automotive industry, lithium-ion batteries are a key component of electric vehicle power systems. They provide vehicles with longer driving range and faster charging speeds, promoting the popularity of electric vehicles and environmentally friendly travel. In the aerospace field, the lightweight and high energy density characteristics of lithium-ion batteries make them an ideal energy choice for drones and electric aircraft, paving the way for future green flights.

[0003] However, lithium-ion batteries may experience lithium plating under high voltage or overcharge conditions. Lithium plating refers to the phenomenon that lithium ions are deposited on the surface of the negative electrode to form metallic lithium during the battery charging and discharging process. This deposition not only causes the battery capacity to decay rapidly, but also increases the internal resistance of the battery, affecting the battery's cycle stability. More seriously, lithium plating may cause internal short circuits in the battery, leading to local overheating, and then triggering thermal runaway reactions. This reaction is irreversible and may eventually cause the battery to burn or explode, posing a great threat to personnel safety and equipment.

[0004] The occurrence of lithium precipitation is often accompanied by chemical reactions inside the battery, which produce a variety of gases, such as hydrogen and methane. The generation and accumulation of these gases can serve as early signals of the lithium precipitation process. Therefore, real-time monitoring of the gas composition and concentration inside the battery is of great significance for early warning of the lithium precipitation process. By installing gas sensors, the internal environment of the battery can be continuously monitored. Once abnormal gas signals are found, such as abnormal increases in gas concentrations, timely measures can be taken, such as reducing the charging current, adjusting the charging and discharging strategy, or performing battery maintenance, to prevent the occurrence of lithium precipitation.

[0005] In addition, the monitoring of gas signals can also provide important information for the battery management system (BMS), helping to optimize the battery's charging and discharging strategy and extend the battery's service life. For example, by analyzing the changing trend of gas signals, the battery's health status and remaining service life can be predicted, thus providing a scientific basis for battery maintenance and replacement. This early warning mechanism based on gas signals can not only improve battery safety, but also improve the overall performance and economy of the battery.

[0006] At present, the detection of gas production of lithium-ion batteries is mostly focused on the thermal runaway process, which mainly involves placing the battery in a closed compartment, using heating, acupuncture or overcharging to trigger thermal runaway of the battery, and then exporting the gas through a pipeline. However, this method does not consider the collection of battery gas in a non-runaway state. The test based on telechemical differential mass spectrometry is only suitable for gas collection of small batteries for materials and verification, not for finished batteries, and lacks gas collection in high-temperature environments. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first purpose of the present invention is to provide a test device for thermal gas generation of lithium batteries, wherein the controller is used to control the charging and discharging device to control the charging and discharging of the lithium battery, so that when the state of charge of the lithium battery reaches a preset charge range, the environmental box is controlled to heat at a preset rate so that the temperature in the sample chamber reaches a first preset temperature threshold, and the first solenoid valve is controlled to be in an open state so that the gas in the sample chamber enters the gas collection device, and the gas collected by the gas collection device at different temperatures is analyzed for composition, thereby enabling the collection of gas at different states of charge and temperatures of the lithium battery, which is of great significance for improving the safety standards of lithium batteries and promoting their safe use in various applications.

[0008] The second object of the present invention is to provide a method for testing thermal gas generation of lithium batteries.

[0009] To achieve the above-mentioned purpose, the first aspect of the present invention proposes a test device for thermal gas production of lithium batteries, the device comprising: an environmental chamber, a sample chamber, a charging and discharging device, a first solenoid valve, a first air duct, a gas collecting device and a controller, wherein the lithium battery is placed in the sample chamber, the sample chamber is placed in the environmental chamber, the sample chamber has a first air duct, the first air duct is connected to the first solenoid valve and the gas collecting device in sequence through the first through hole of the environmental chamber, the environmental chamber has a heating function, wherein the controller is used to control the charging and discharging device to control the charging and discharging of the lithium battery, so that when the charge state of the lithium battery reaches a preset charge range, the environmental chamber is controlled to heat at a preset rate so that the temperature in the sample chamber reaches a first preset temperature threshold, and the first solenoid valve is controlled to be in an open state so that the gas in the sample chamber enters the gas collecting device, and the composition of the gas collected by the gas collecting device at different temperatures is analyzed.

[0010] According to the test equipment for thermal gas generation of lithium batteries of the embodiment of the present invention, the controller is used to control the charge and discharge device to control the charge and discharge of the lithium battery, so that when the state of charge of the lithium battery reaches the preset charge range, the environmental box is controlled to heat at a preset rate so that the temperature in the sample chamber reaches the first preset temperature threshold, and the first solenoid valve is controlled to be in an open state so that the gas in the sample chamber enters the gas collection device, and the gas collected by the gas collection device at different temperatures is analyzed for composition. Therefore, the test equipment can realize the collection of gas from lithium batteries at different states of charge and different temperatures, which is of great significance for improving the safety standards of lithium batteries and promoting their safe use in various applications.

[0011] In addition, the lithium battery thermal gas generation testing equipment according to the above embodiment of the present invention may also have the following additional technical features:

[0012] According to one embodiment of the present invention, it also includes: a first three-way valve and a vacuum pumping device, the first three-way valve is arranged on the first air duct, the first end of the first three-way valve is connected to the first solenoid valve, the second end of the first three-way valve is connected to the gas collecting device, and the third end of the first three-way valve is connected to the vacuum pumping device; wherein the controller is also used to control the first solenoid valve to be in a closed state and control the second end of the first three-way valve to be connected to the third end of the first three-way valve during the process of controlling the vacuum pumping device to be in a working state, and control the first end of the first three-way valve to be connected to the second end of the first three-way valve after the vacuum pumping device has been working for a first preset time.

[0013] According to one embodiment of the present invention, it also includes: a second solenoid valve, a second air duct and an inert gas storage device, wherein the second air duct is connected to the second solenoid valve and the inert gas storage device in sequence through the second through hole of the environmental box; wherein the controller is also used to control the second solenoid valve to be in an open state so that the gas stored in the inert gas storage device can enter the sample chamber.

[0014] According to one embodiment of the present invention, it further includes: a gas flow meter, which is arranged on the second gas duct and connected to the inert gas storage device, and is used to adjust the flow of the gas entering the sample chamber.

[0015] According to one embodiment of the present invention, it also includes: a second three-way valve, the first end of the second three-way valve is connected to the second solenoid valve, the second end of the second three-way valve is connected to the gas flow meter, and the third end of the second three-way valve is connected to the vacuum pumping device; wherein the controller is also used to control the second solenoid valve to be in a closed state during the process of controlling the vacuum pumping device to be in a working state, and to control the first end of the second three-way valve to be connected to the third end of the second three-way valve, and to control the second end of the second three-way valve to be connected to the third end of the second three-way valve.

[0016] According to one embodiment of the present invention, the controller is also used to: after controlling the vacuum device to work for a second preset time, control the inert gas storage device to inject gas into the second gas duct, and after injecting the gas, control the vacuum device to be in a working state again, and control the second solenoid valve to be in a closed state, and control the first end of the second three-way valve to be connected to the third end of the second three-way valve, and control the second end of the second three-way valve to be connected to the third end of the second three-way valve.

[0017] According to one embodiment of the present invention, the gas stored in the inert gas storage device is argon.

[0018] According to one embodiment of the present invention, before placing the lithium battery in the sample chamber, the controller is further used to control the charging and discharging device to adjust the lithium battery to an empty state.

[0019] According to an embodiment of the present invention, before controlling the charging and discharging device, the controller is further used to control the ambient temperature in the environmental box to be lower than a second preset temperature threshold.

[0020] To achieve the above-mentioned purpose, the second aspect of the embodiment of the present invention proposes a testing method for thermal gas production of a lithium battery, the method comprising: adjusting the state of charge of the lithium battery and the temperature of the lithium battery; when the state of charge reaches a preset charge range and the temperature reaches a preset temperature threshold, obtaining the gas generated by the lithium battery at different ambient temperatures, and performing component analysis based on the gas.

[0021] According to the test method for thermal gas generation of lithium batteries in the embodiment of the present invention, the state of charge and the temperature of the lithium battery are adjusted; when the state of charge reaches a preset charge range and the temperature reaches a preset temperature threshold, the gas generated by the lithium battery at different ambient temperatures is obtained, and the composition analysis is performed based on the gas. Therefore, the method can realize the collection of gas at different states of charge and different temperatures of lithium batteries, which is of great significance for improving the safety standards of lithium batteries and promoting their safe use in various applications.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a block diagram of a testing device for thermal gas generation of a lithium battery according to an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a test device for thermal gas generation of a lithium battery according to a specific embodiment of the present invention;

[0025] Figure 3 The figure is a flow chart of a method for testing thermal gas generation of a lithium battery according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] The following describes a test device for thermal gas generation of a lithium battery and a test method for thermal gas generation of a lithium battery provided in an embodiment of the present invention with reference to the accompanying drawings.

[0028] Figure 1 Schematic diagram of a block diagram of a test device for thermal gas generation of a lithium battery according to an embodiment of the present invention.

[0029] like Figure 1 As shown, the testing equipment 100 for thermal gas generation of the lithium battery 80 may include: an environmental chamber 10, a sample chamber 20, a charging and discharging device 30, a first solenoid valve 40, a first gas guide line 50, a gas collection device 60 and a controller 70.

[0030] The lithium battery 80 is placed in the sample chamber 20, the sample chamber 20 is placed in the environmental box 10, the sample chamber 20 has a first air guide 50, the first air guide 50 is connected to the first electromagnetic valve 40 and the gas collection device 60 in sequence through the first through hole of the environmental box 10, and the environmental box 10 has a heating function. The controller 70 is used to control the charging and discharging device 30 to control the charging and discharging of the lithium battery 80, so that when the state of charge of the lithium battery 80 reaches the preset charge range, the environmental box 10 is controlled to heat at a preset rate so that the temperature in the sample chamber 20 reaches the first preset temperature threshold, and the first electromagnetic valve 40 is controlled to be in an open state so that the gas in the sample chamber 20 enters the gas collection device 60, and the gas collected by the gas collection device 60 at different temperatures is analyzed for components. The preset charge range, the preset rate and the first preset temperature threshold can be determined according to actual conditions.

[0031] Specifically, in one embodiment of the present invention, the lithium battery 80 may be a lithium-ion battery cell, and the lithium battery 80 may be placed in the sample chamber 20, which is made of a steel plate and has an upper cover ( Figure 2 The upper cover 15) in the tank is removable and sealed with a gasket and pressurized with a nut. The gasket can withstand a high temperature of 200°C and can be made of silicone or graphite. Figure 2 As shown, the sample compartment upper cover 15 may also have positive and negative charging and voltage detection interfaces (positive voltage and charging interface 13 and negative voltage and charging interface 14), which are connected to the upper cover 15 by welding. The interface located at one end of the outer side of the upper cover 15 is directly connected to the charging and discharging device 30, and the interface located on the inner side of the compartment body is respectively connected to the positive and negative electrodes of the lithium battery 80. In addition, the sample compartment 20 upper cover also has a thermocouple connection port, which is connected to the upper cover 15 by welding, and the upper cover 15 has two thermocouple connection interfaces (temperature sensing interface 11 in the sample compartment and temperature sensing interface 12 of the lithium battery), one is connected to the surface of the battery, and the other is placed in the space of the sample compartment 20 for monitoring the internal temperature of the sample compartment 20. The sample compartment 20 also has a first gas duct 50, which is made of steel and is welded to the sample compartment 20 for gas output.

[0032] The first air guide line 50 is connected to the first electromagnetic valve 40 and the gas collection device 60 in sequence through the first through hole of the environmental box 10. The first electromagnetic valve 40 can control the opening and closing of the first air guide line 50, so that when the first air guide line 50 is opened, the gas collection device 60 can collect the gas in the sample chamber 20. The environmental box 10 has a high-temperature heating function, the temperature range covers -20°C to 200°C, the temperature rise rate has the ability of ≥5°C / min, the temperature fluctuation is ≤0.5°C, and the temperature uniformity is ≤0.5°C. The environmental box 10 can be used to control the temperature of the sample chamber 20.

[0033] The lithium battery 80 is placed in the sample compartment 20, and the positive and negative poles of the battery are connected to the charging interface and the voltage monitoring interface in the sample compartment 20. The battery can be connected to the charging and discharging device 30 through the charging interface, so that the lithium battery 80 is charged and discharged through the charging and discharging device 30. In order to prevent the lithium battery 80 from reacting adversely with oxygen and water vapor during the charging and discharging process, thereby ensuring the safety and accuracy of the test, the discharged lithium battery 80 and the sample compartment 20 can be placed in a glove environment. The glove box environment requires an argon atmosphere with an oxygen content of <1ppm and a water content of <1ppm. The sample compartment cover 15 can be opened, and the lithium battery 80 can be placed in the sample compartment 20. The positive and negative poles of the battery are respectively connected to the charging interface and the voltage monitoring interface in the sample compartment 20. The thermocouple for monitoring the temperature is also connected to the interface for monitoring the temperature of the upper cover 15. The thermocouple for monitoring the battery temperature in the sample compartment 20 is fixed to the center of the large surface of the single battery using a high temperature resistant tape.

[0034] In order to prevent the lithium battery 80 from generating gas under high temperature and causing the lithium battery 80 to rupture, a 1mm ceramic steel needle can be used to puncture the explosion vent of the lithium battery 80 with a hole no larger than 1.5mm in advance, so that the battery gas can escape from the inside, and the hole can be sealed with high-temperature tape, and then the sample compartment cover 15 is closed, and the nut is used to pressurize to complete the sealing of the sample compartment 20. The sample compartment 20 is taken out from the glove box, and the sample compartment 20 with the lithium battery 80 is placed in the environmental box 10, and the charging port and voltage monitoring port of the upper cover 15 are connected to the charging and discharging device 30, and the first solenoid valve 40 is led out through the first through hole of the environmental box 10 and placed outside the environmental box 10, and kept closed.

[0035] The controller 70 can start the charging and discharging device 30 to charge the lithium battery 80 until the state of charge of the lithium battery 80 reaches a preset charge range, for example, the preset charge range is 100-115%, so as to complete the lithium deposition process of the lithium battery 80. That is, by placing the lithium battery 80 under an overcharge condition, the lithium deposition phenomenon is simulated.

[0036] When the state of charge of the lithium battery 80 reaches the preset charge range, the environmental box 10 can be controlled to heat at a preset rate so that the temperature in the sample chamber 20 reaches a preset temperature threshold, and the first solenoid valve 40 is controlled to be in an open state so that the gas in the sample chamber 20 enters the gas collection device 60. For example, the preset rate may be 5°C / min, and the preset temperature threshold may be 60 degrees Celsius. That is, by controlling the environmental box 10 to start from room temperature, the temperature in the sample chamber 20 is raised to 60 degrees Celsius at a rate of 5°C / min, so that the gas collection device 60 can collect the gas generated by the lithium battery 80 when thermal runaway does not occur.

[0037] When the preset temperature threshold is reached, heating can be continued. A gradient heating method can be used for heating, such as taking 5°C as a temperature step, starting from 60°C, and heating at a rate of 5°C / min. The temperature is maintained for every 5°C increase in the environment until the temperature of the lithium battery 80 reaches the ambient temperature for one hour, and then the next 5°C temperature step is started until the temperature reaches 200°C or the battery has thermal runaway. In the above-mentioned heating process, after each temperature step is completed, the corresponding temperature gas can be collected to complete the gas collection at different high temperatures, so as to perform component analysis according to the gas collected by the gas collection device 60 at different temperatures. For example, the collected gas can be transferred to a gas phase mass spectrometer for component analysis to determine the type and concentration of thermal gas produced by the lithium battery 80 at different temperatures, and to analyze the thermal stability and gas production characteristics of the lithium battery 80 at different temperatures. As a result, the gas production behavior of the lithium battery 80 under different charge states and different temperature conditions can be understood in detail, providing important data support for the safe use and performance optimization of the battery.

[0038] According to one embodiment of the present invention, Figure 2 As shown, the test equipment 100 for thermal gas generation of the lithium battery 80 also includes: a first three-way valve 42 and a vacuum device 44, the first three-way valve 42 is arranged on the first gas guide line 50, the first end of the first three-way valve 42 is connected to the first solenoid valve 40, the second end of the first three-way valve 42 is connected to the gas collecting device 60, and the third end of the first three-way valve 42 is connected to the vacuum device 44; wherein the controller 70 ( Figure 2 The first electromagnetic valve 40 is also used to control the first electromagnetic valve 40 to be in a closed state and control the second end of the first three-way valve 42 to be connected to the third end of the first three-way valve 42 during the process of controlling the vacuum device 44 to be in a working state, and control the first end of the first three-way valve 42 to be connected to the second end of the first three-way valve 42 after the vacuum device 44 works for a first preset time. The first preset time can be determined according to actual conditions.

[0039] Specifically, the first three-way valve 42 has three ports: a first end, a second end, and a third end. The first three-way valve 42 can control the flow direction of the gas, allowing the gas to switch and flow between different ports. The vacuum device 44 is used to create and maintain a vacuum environment to ensure that there is no air or other impurity gases in the test equipment, thereby ensuring that the collected gas is pure and can accurately simulate the gas production of the lithium battery 80 in actual use.

[0040] In the process of controlling the vacuum device 44 to be in the working state, the controller 70 first controls the first electromagnetic valve 40 to be in the closed state to prevent gas from overflowing during the vacuuming process, and controls the second end of the first three-way valve 42 to be connected to the third end of the first three-way valve 42, so that the gas can flow from the gas collection device 60 through the first gas guide line 50 and the first electromagnetic valve 40 to the vacuum device 44, so as to realize the vacuuming of the gas collection device 60 and the first gas guide line 50, so that the gas collection device 60 is in a negative pressure state. After the vacuum device 44 works for a preset time, for example, the first preset time can be 3 minutes, after the vacuum device 44 works for 3 minutes, the first end of the first three-way valve 42 can be controlled to be connected to the second end of the first three-way valve 42, so that when the first electromagnetic valve 40 is opened, since the gas collection device 60 is in a negative pressure state, the gas in the sample chamber 20 can be guided to the gas collection device 60 for gas collection and analysis.

[0041] According to one embodiment of the present invention, Figure 2 As shown, the test equipment 100 for thermal gas generation of lithium battery 80 further includes: a second solenoid valve 82, a second gas pipeline 84 and an inert gas storage device 86, wherein the second gas pipeline 84 is sequentially connected to the second solenoid valve 82 and the inert gas storage device 86 through the second through hole of the environmental box 10; wherein the controller 70 is also used to control the second solenoid valve 82 to be in an open state so that the gas stored in the inert gas storage device 86 enters the sample chamber 20. The gas stored in the inert gas storage device 86 is argon.

[0042] Specifically, the test equipment 100 for thermal gas generation of the lithium battery 80 may also include a second solenoid valve 82, a second gas pipeline 84 and an inert gas storage device 86. The second gas pipeline 84 is connected to the second solenoid valve 82 and the inert gas storage device 86 in sequence through the second through hole of the environmental box 10, that is, the second gas pipeline 84 is a channel connecting the inert gas storage device 86 and the sample chamber 20, ensuring that the gas can flow smoothly from the inert gas storage device 86 to the sample chamber 20. The second solenoid valve 82 can be opened or closed by the command of the controller 70 to control the inert gas to enter the sample chamber 20. The inert gas storage device 86 is used to store inert gas, such as argon. Inert gas is not easy to react chemically with other substances and is often used to create an oxygen-free or low-oxygen environment to prevent or reduce chemical reactions that may occur inside the lithium battery 80.

[0043] The controller 70 can control the second solenoid valve 82 to be in an open state so that the gas stored in the inert gas storage device 86 enters the sample chamber 20. That is, when the second solenoid valve 82 is opened, the inert gas (such as argon) enters the sample chamber 20 from the inert gas storage device 86 through the second gas pipeline 84, which helps to maintain a stable internal environment during the test process and reduce oxidation or other chemical reactions that may affect the test results. In addition, by delivering argon gas to the sample chamber 20, the original gas distribution in the sample chamber 20 can be made more uniform, so as to improve the accuracy of the gas collected by the gas collection device 60.

[0044] According to one embodiment of the present invention, Figure 2 As shown, the testing equipment 100 for thermal gas generation of the lithium battery 80 further includes: a gas flow meter 88 , which is disposed on the second gas duct 84 and connected to the inert gas storage device 86 for adjusting the flow of the gas entering the sample chamber 20 .

[0045] Specifically, the test equipment 100 for thermal gas generation of the lithium battery 80 further includes a gas flow meter 88, which is disposed on the second gas guide line 84 and connected to the inert gas storage device 86, and is used to adjust the flow rate of the gas entering the sample chamber 20. In other words, the gas flow meter 88 is used to measure and control the flow rate of the inert gas entering the sample chamber 20 through the second gas guide line 84, so as to ensure that the gas enters the sample chamber 20 at a constant or adjustable rate. For example, the gas flow rate is adjusted to 10 ml / min to 50 ml / min.

[0046] According to one embodiment of the present invention, Figure 2 As shown, the test equipment 100 for thermal gas production of the lithium battery 80 also includes: a second three-way valve 90, the first end of the second three-way valve 90 is connected to the second solenoid valve 82, the second end of the second three-way valve 90 is connected to the gas flow meter 88, and the third end of the second three-way valve 90 is connected to the gas flow meter 88; wherein the controller 70 is also used to control the second solenoid valve 82 to be in a closed state during the process of controlling the vacuum pumping device 44 to be in a working state, and to control the first end of the second three-way valve 90 to be connected to the third end of the second three-way valve 90, and to control the second end of the second three-way valve 90 to be connected to the third end of the second three-way valve 90.

[0047] Specifically, the test equipment 100 for thermal gas generation of lithium battery 80 also includes a second three-way valve 90, which is a multi-port valve that can control the flow direction of gas and allow gas to switch and circulate between different ports, that is, it has three ports: a first end, a second end, and a third end. The first end of the second three-way valve 90 is connected to the second solenoid valve 82, which is used to control the passage of inert gas (such as argon) from the inert gas storage device 86 to the sample chamber 20. The second end is connected to the gas flow meter 88 as an input port for inert gas. The third end is connected to the vacuum device 44, which is used to extract gas when necessary to create or maintain a vacuum environment.

[0048] In the process of controlling the vacuum pumping device 44 to be in working state, the controller 70 also needs to control the second solenoid valve 82 to be in a closed state, that is, to prevent the air in the sample chamber 20 from being extracted, and control the first end of the second three-way valve 90 to be connected with the third end of the second three-way valve 90 to vacuum the gas in the second solenoid valve 82, the second three-way valve 90 and the pipeline where the vacuum pumping device 44 is located, and after a period of time, the second end of the second three-way valve 90 can be controlled to be connected with the third end of the second three-way valve 90 to vacuum the gas in the pipeline where the inert gas storage device 86, the gas flow meter 88, the second three-way valve 90 and the vacuum pumping device 44 are located, so as to prevent other gases from affecting the gas in the sample chamber 20 and ensure the accuracy of the test results.

[0049] According to one embodiment of the present invention, the controller 70 is further used to: after controlling the vacuum device 44 to work for the second preset time, control the inert gas storage device 86 to inject gas into the second gas pipeline 84, and after injecting gas, control the vacuum device to be in a working state again, control the second solenoid valve 82 to be in a closed state, control the first end of the second three-way valve 90 to be connected to the third end of the second three-way valve 90, and control the second end of the second three-way valve 90 to be connected to the third end of the second three-way valve 90. The second preset time can be determined according to actual conditions.

[0050] Specifically, after the vacuum device 44 is controlled to work for a second preset time, for example, the second preset time can be 3 minutes, that is, after the vacuum device 44 works for 3 minutes, the controller 70 can control the inert gas storage device 86 to inject gas into the second gas pipeline 84, and the original gas (such as air) in the pipeline can be pushed out more effectively by injecting gas. Therefore, after injecting gas, the vacuum device can be controlled to be in a working state again, and the second electromagnetic valve 82 can be controlled to be in a closed state, and the first end of the second three-way valve 90 can be controlled to be connected with the third end of the second three-way valve 90 to vacuumize the gas in the pipeline where the second electromagnetic valve 82, the second three-way valve 90 and the vacuum device 44 are located, and after a period of time, the second end of the second three-way valve 90 can be controlled to be connected with the third end of the second three-way valve 90 to vacuumize the gas in the pipeline where the inert gas storage device 86, the gas flowmeter 88, the second three-way valve 90 and the vacuum device 44 are located, so as to prevent other gases from affecting the gas in the sample chamber 20 and ensure the accuracy of the test results. The above steps are repeated multiple times to complete the gas replacement in the pipeline.

[0051] According to an embodiment of the present invention, before placing the lithium battery 80 in the sample chamber 20 , the controller 70 is further configured to control the charging and discharging device 30 to adjust the lithium battery 80 to an empty state.

[0052] Specifically, before placing the lithium battery 80 in the sample chamber 20, the SOC (State of Charge) of the lithium battery 80 cell can also be adjusted to 0% to ensure that the lithium battery 80 is in an empty state, that is, to ensure that all tested lithium batteries 80 start from the same starting conditions, which is convenient for comparing the performance and behavior of the lithium battery 80 under different test conditions, and at the same time better simulating and studying various situations that the lithium battery 80 may encounter in actual use. It can provide a known starting point for subsequent high temperature tests or other types of tests, ensuring the accuracy and effectiveness of the test.

[0053] According to an embodiment of the present invention, before controlling the charging and discharging device 30, the controller 70 is further used to control the ambient temperature in the environmental box 10 to be lower than a second preset temperature threshold, wherein the second preset temperature threshold can be determined according to actual conditions.

[0054] Specifically, before controlling the charging and discharging device 30, the controller 70 is also used to control the ambient temperature in the environmental box 10 to be lower than the second preset temperature threshold. Among them, the second preset temperature threshold can be -10°C. That is to say, when the ambient temperature in the environmental box 10 is low, the lithium deposition phenomenon of the lithium battery 80 will be more obvious, that is, under low temperature conditions, the chemical reaction rate inside the lithium battery 80 will slow down, and the migration rate of lithium ions will also decrease, which will increase the probability of lithium deposition, thereby helping to study and test the behavior of the battery in the lithium deposition state. For example, the temperature of the environmental box 10 can be adjusted to -20°C to 0°C, preferably -10°C (second preset temperature threshold), and the temperature of the lithium battery 80 is monitored until the temperature of the lithium battery 80 reaches near the preferred temperature (such as between -10.5°C and -9.5°C), and the temperature range is maintained for more than 1 hour.

[0055] In summary, according to the test equipment for thermal gas production of lithium batteries in the embodiment of the present invention, the controller is used to control the charge and discharge device to control the charge and discharge of the lithium battery, so that when the state of charge of the lithium battery reaches the preset charge range, the environmental box is controlled to heat at a preset rate so that the temperature in the sample chamber reaches the preset temperature threshold, and the first solenoid valve is controlled to be in an open state so that the gas in the sample chamber enters the gas collection device, and the gas collected by the gas collection device at different temperatures is analyzed for composition. Therefore, the test equipment can realize the collection of gas from lithium batteries at different states of charge and different temperatures, which is of great significance for improving the safety standards of lithium batteries and promoting their safe use in various applications.

[0056] Corresponding to the above embodiment, the present invention also proposes a method for testing thermal gas generation of a lithium battery.

[0057] like Figure 3 As shown, the test method for thermal gas generation of a lithium battery according to an embodiment of the present invention may include the following steps:

[0058] S1, adjusting the state of charge of the lithium battery and the temperature of the lithium battery.

[0059] S2, when the state of charge reaches a preset charge range and the temperature reaches a preset temperature threshold, obtain the gas generated by the lithium battery at different ambient temperatures and perform component analysis based on the gas. The preset charge range and the preset temperature threshold can be determined according to actual conditions.

[0060] Specifically, the state of charge is a measure of the current charge of a lithium battery, usually expressed as a percentage. Adjusting the state of charge to a preset charge range means charging and discharging the battery so that its charge reaches a specific level, which is the starting point for the test. The temperature of the lithium battery can be adjusted by placing it in a specific environmental chamber and adjusting the temperature of the environmental chamber to a preset temperature threshold. Temperature has a significant effect on battery performance and chemical reactions. For example, the preset charge range is 100% to 120%, and the preset temperature threshold can be 60 degrees Celsius. When the state of charge reaches the preset charge range and the temperature reaches the preset temperature threshold, the lithium battery may produce gases at a specific ambient temperature. These gases may include hydrogen, methane, carbon monoxide, etc., and their generation may be related to the chemical reactions inside the battery.

[0061] The temperature of the lithium battery can be further adjusted to obtain the gas generated by the lithium battery at different ambient temperatures. For example, the gas escaping from the lithium battery can be collected by using a gas collection device (such as an air bag or a gas cylinder). The collected gas is transferred to a gas chromatograph or other analytical equipment for component analysis to determine the type and concentration of the gas. In this way, the performance and safety of lithium batteries at different ambient temperatures can be comprehensively evaluated, providing a scientific basis for the research and development and application of lithium batteries.

[0062] It should be noted that for details not disclosed in the test method for thermal gas generation of a lithium battery in an embodiment of the present invention, please refer to the details disclosed in the test device for thermal gas generation of a lithium battery in an embodiment of the present invention, and the details will not be repeated here.

[0063] According to the test method for thermal gas generation of lithium batteries in the embodiment of the present invention, the state of charge and the temperature of the lithium battery are adjusted; when the state of charge reaches a preset charge range and the temperature reaches a preset temperature threshold, the gas generated by the lithium battery at different ambient temperatures is obtained, and the composition analysis is performed based on the gas. Therefore, the method can realize the collection of gas at different states of charge and different temperatures of lithium batteries, which is of great significance for improving the safety standards of lithium batteries and promoting their safe use in various applications.

[0064] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection portion with one or more wirings (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0065] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0066] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0067] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0068] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0069] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A test device for thermal gas generation of lithium batteries, characterized in that: The device comprises: an environmental box, a sample chamber, a charging and discharging device, a first electromagnetic valve, a first air guide line, a gas collecting device and a controller, wherein the lithium battery is placed in the sample chamber, the sample chamber is placed in the environmental box, the sample chamber has a first air guide line, the first air guide line is connected to the first electromagnetic valve and the gas collecting device in sequence through the first through hole of the environmental box, and the environmental box has a heating function, wherein, The controller is used to control the charging and discharging device to control the charging and discharging of the lithium battery, so that when the charge state of the lithium battery reaches a preset charge range, the environmental box is controlled to heat at a preset rate so that the temperature in the sample chamber reaches a first preset temperature threshold, and the first solenoid valve is controlled to be in an open state so that the gas in the sample chamber enters the gas collection device, and the composition of the gas collected by the gas collection device at different temperatures is analyzed.

2. The lithium battery thermal gas generation testing equipment according to claim 1, characterized in that: Also includes: A first three-way valve and a vacuum pumping device, wherein the first three-way valve is arranged on the first air guide line, a first end of the first three-way valve is connected to the first solenoid valve, a second end of the first three-way valve is connected to the gas collecting device, and a third end of the first three-way valve is connected to the vacuum pumping device; wherein The controller is also used to control the first solenoid valve to be in a closed state and control the second end of the first three-way valve to be connected to the third end of the first three-way valve during the process of controlling the vacuum pumping device to be in a working state, and control the first end of the first three-way valve to be connected to the second end of the first three-way valve after the vacuum pumping device has been working for a first preset time.

3. The testing equipment for thermal gas generation of lithium batteries according to claim 2, characterized in that: Also includes: A second solenoid valve, a second air pipeline and an inert gas storage device, wherein the second air pipeline is connected to the second solenoid valve and the inert gas storage device in sequence through the second through hole of the environmental box; wherein, The controller is further used to control the second solenoid valve to be in an open state so that the gas stored in the inert gas storage device can enter the sample chamber.

4. The lithium battery thermal gas generation testing equipment according to claim 3, characterized in that: Also includes: A gas flow meter is arranged on the second gas guide pipe and connected to the inert gas storage device, and is used to adjust the flow of the gas entering the sample chamber.

5. The lithium battery thermal gas generation testing equipment according to claim 4, characterized in that: Also includes: a second three-way valve, wherein a first end of the second three-way valve is connected to the second solenoid valve, a second end of the second three-way valve is connected to the gas flow meter, and a third end of the second three-way valve is connected to the vacuum pump; wherein The controller is also used to control the second solenoid valve to be in a closed state, control the first end of the second three-way valve to be connected to the third end of the second three-way valve, and control the second end of the second three-way valve to be connected to the third end of the second three-way valve during the process of controlling the vacuum pumping device to be in a working state.

6. The lithium battery thermal gas generation testing equipment according to claim 5, characterized in that: The controller is also used for: After controlling the vacuum device to work for a second preset time, controlling the inert gas storage device to inject gas into the second gas duct, and after injecting the gas, controlling the vacuum device to be in a working state again, controlling the second solenoid valve to be in a closed state, controlling the first end of the second three-way valve to be connected to the third end of the second three-way valve, and controlling the second end of the second three-way valve to be connected to the third end of the second three-way valve.

7. The lithium battery thermal gas generation testing equipment according to any one of claims 3 to 5, characterized in that: The gas stored in the inert gas storage device is argon gas.

8. The lithium battery thermal gas generation testing equipment according to claim 1, characterized in that: Before placing the lithium battery in the sample chamber, the controller is further used to control the charging and discharging device to adjust the lithium battery to an empty state.

9. The lithium battery thermal gas generation testing equipment according to claim 1, characterized in that: Before controlling the charging and discharging device, the controller is further used to control the ambient temperature in the environmental box to be lower than a second preset temperature threshold.

10. A method for testing thermal gas generation of a lithium battery, characterized in that: The method comprises: Adjusting the state of charge of the lithium battery and the temperature of the lithium battery; When the state of charge reaches a preset charge range and the temperature reaches a preset temperature threshold, gas generated by the lithium battery at different ambient temperatures is obtained, and component analysis is performed based on the gas.

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