Test apparatus and test method for lithium battery heat gas generation

Abstract

This invention discloses a testing device and method for thermal gas generation from lithium batteries. The device includes an environmental chamber, a sample chamber, a charging and discharging device, a first solenoid valve, a first gas guide pipe, a gas collection device, and a controller. The sample chamber has a first gas guide pipe, which is connected to the first solenoid valve and the gas collection device sequentially through a first through-hole of the environmental chamber. The environmental chamber has a heating function. The controller controls the charging and discharging device to charge and discharge the lithium battery. When the state of charge of the lithium battery reaches a preset charge range, the controller controls the environmental chamber to heat at a preset rate so that the temperature inside the sample chamber reaches a preset temperature threshold. The controller also controls the first solenoid valve to be open so that the gas inside the sample chamber enters the gas collection device. The controller also performs component analysis on the gas collected by the gas collection device at different temperatures. This enables the collection of gas from the lithium battery at different states of charge and different temperatures.

Description

Technical Field

[0001] This invention relates to the field of battery safety testing technology, and in particular to a testing device and a testing method for thermal gas generation in lithium batteries. Background Technology

[0002] Lithium-ion batteries, due to their superior performance, have become the core of modern energy technology. In the field of energy storage, they provide efficient energy storage solutions for renewable energy sources such as solar and wind power, balancing energy supply and demand and improving the stability and reliability of the power grid. In the automotive industry, lithium-ion batteries are a key component of electric vehicle power systems, providing vehicles with longer driving ranges and faster charging speeds, promoting the popularization 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 where lithium ions deposit on the surface of the negative electrode to form metallic lithium during the battery's charging and discharging process. This deposition not only leads to a rapid decline in battery capacity but also increases the battery's internal resistance, affecting its cycle stability. More seriously, lithium plating can cause internal short circuits, leading to localized overheating and potentially triggering thermal runaway. This reaction is irreversible and may ultimately cause the battery to burn or explode, posing a significant threat to personnel safety and equipment.

[0004] Lithium plating often occurs alongside internal chemical reactions within the battery, producing various gases such as hydrogen and methane. The generation and accumulation of these gases can serve as early warning signs of lithium plating. Therefore, real-time monitoring of the gas composition and concentration inside the battery is crucial for early warning of lithium plating. By installing gas sensors, the internal environment of the battery can be continuously monitored. Once abnormal gas signals are detected, such as an abnormally high gas concentration, timely measures can be taken, such as reducing the charging current, adjusting the charging and discharging strategy, or performing battery maintenance, to prevent lithium plating.

[0005] Furthermore, monitoring gas signals can provide crucial information to the battery management system (BMS), helping to optimize battery charging and discharging strategies and extend battery life. For example, by analyzing trends in gas signal changes, the health status and remaining lifespan of the battery can be predicted, providing a scientific basis for battery maintenance and replacement. This gas signal-based early warning mechanism not only improves battery safety but also enhances overall battery performance and cost-effectiveness.

[0006] Current detection methods for gas generation in lithium-ion batteries primarily focus on the thermal runaway process. This involves placing the battery in a sealed chamber and triggering thermal runaway through methods such as heating, puncture, or overcharging, then venting the gas through pipelines. However, this approach does not consider the collection of gas from the battery in the unrunaway state. Furthermore, testing based on telecommunications chemical differential mass spectrometry is only suitable for gas collection from small, material-grade and verification batteries, and is not applicable to finished batteries. Additionally, it lacks the capability to collect gas in high-temperature environments. Summary of the Invention

[0007] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to provide a testing device for thermal gas generation from lithium batteries. A controller is used to control the charging and discharging of the lithium battery via a charging and discharging device. When the lithium battery's state of charge reaches a preset range, the controller heats the environmental chamber at a preset rate to raise the temperature inside the sample chamber to a first preset temperature threshold. Simultaneously, the controller opens a first solenoid valve to allow gas from the sample chamber to enter a gas collection device. Furthermore, the controller performs component analysis on the gas collected at different temperatures. This enables the collection of gas from lithium batteries at different states of charge and temperatures, which is of great significance for improving the safety standards of lithium batteries and promoting their safe use in various applications.

[0008] The second objective of this invention is to provide a test method for thermal gas generation in lithium batteries.

[0009] To achieve the above objectives, a first aspect of the present invention provides a testing device for thermal gas generation from a lithium battery. The device includes an environmental chamber, a sample chamber, a charging / discharging device, a first solenoid valve, a first gas conduit, a gas collection device, and a controller. The lithium battery is placed inside the sample chamber, which is also placed inside the environmental chamber. The sample chamber has a first gas conduit, which is sequentially connected to the first solenoid valve and the gas collection device through a first through-hole in the environmental chamber. The environmental chamber has a heating function. The controller controls the charging / discharging device to charge and discharge the lithium battery. When the state of charge of the lithium battery reaches a preset charge range, the controller controls the environmental chamber to heat at a preset rate to raise the temperature inside the sample chamber to a first preset temperature threshold. The controller also controls the first solenoid valve to be open, allowing gas from the sample chamber to enter the gas collection device. Furthermore, the controller performs component analysis on the gas collected by the gas collection device at different temperatures.

[0010] According to an embodiment of the present invention, a testing device for thermal gas generation from lithium batteries includes a controller that controls the charging and discharging of the lithium battery via a charging and discharging device. When the state of charge (SOC) of the lithium battery reaches a preset range, the controller controls the environmental chamber to heat at a preset rate to raise the temperature inside the sample chamber to a first preset temperature threshold. The controller also controls a first solenoid valve to open, allowing gas from the sample chamber to enter a gas collection device. Furthermore, the controller performs component analysis on the gas collected by the gas collection device at different temperatures. Therefore, this testing device enables the collection of gas from lithium batteries at different SOCs and temperatures, which is of great significance for improving lithium battery safety standards and promoting their safe use in various applications.

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

[0012] According to one embodiment of the present invention, the device further includes: a first three-way valve and a vacuuming device, wherein the first three-way valve is disposed on the first gas guide pipe, 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 vacuuming device; wherein the controller is further configured to, during the process of controlling the vacuuming device to be in the working state, control the first solenoid valve to be in the 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, and after the vacuuming device has been in operation for a first preset time, control the first end of the first three-way valve to be connected to the second end of the first three-way valve.

[0013] According to one embodiment of the present invention, the device further includes: a second solenoid valve, a second gas guide line, and an inert gas storage device, wherein the second gas guide line is sequentially connected to the second solenoid valve and the inert gas storage device through a second through hole of the environmental chamber; wherein the controller is further configured to control the second solenoid valve to be in an open state so that the gas stored in the inert gas storage device enters the sample chamber.

[0014] According to one embodiment of the present invention, it further includes: a gas flow meter, which is disposed on the second gas guide pipe and connected to the inert gas storage device, for adjusting the flow rate of gas entering the sample chamber.

[0015] According to one embodiment of the present invention, the device further 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 pumping device; wherein the controller is further configured to, during the process of controlling the vacuum pumping device to be in the working state, control the second solenoid valve to be in the 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.

[0016] According to an embodiment of the present invention, the controller is further configured to: after controlling the vacuum device to operate for a second preset time, control the inert gas storage device to inject gas into the second gas guide pipe, and after injecting gas, control the vacuum device to operate again, control the second solenoid valve to be closed, 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 configured to control the charging and discharging device to adjust the lithium battery to a depleted state.

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

[0020] To achieve the above objectives, a second aspect of the present invention provides a method for testing thermally generated gas from a lithium battery. The method includes: adjusting the state of charge (SOC) and temperature of the lithium battery; acquiring the gas generated by the lithium battery at different ambient temperatures when the SOC reaches a preset SOC range and the temperature reaches a preset temperature threshold, and performing component analysis based on the gas.

[0021] According to the present invention, a method for testing the thermally generated gas from a lithium battery involves adjusting the state of charge (SOC) and temperature of the lithium battery. When the SOC reaches a preset range and the temperature reaches a preset temperature threshold, the gas generated by the lithium battery at different ambient temperatures is acquired, and its composition is analyzed. Therefore, this method enables the collection of gas from lithium batteries at different SOCs and temperatures, 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 invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

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

[0024] Figure 2 This is a schematic diagram of a testing device for thermal gas generation from a lithium battery according to a specific embodiment of the present invention.

[0025] Figure 3 This is a flowchart of a test method for thermal gas generation in a lithium battery according to an embodiment of the present invention. Detailed Implementation

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

[0027] The following description, with reference to the accompanying drawings, describes the testing equipment and method for testing thermal gas generation in lithium batteries according to embodiments of the present invention.

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

[0029] like Figure 1 As shown, the testing equipment 100 for the 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 pipe 50, a gas collection device 60, and a controller 70.

[0030] The lithium battery 80 is placed inside the sample chamber 20, which is then placed inside the environmental chamber 10. The sample chamber 20 has a first gas guide pipe 50, which is connected to a first solenoid valve 40 and a gas collection device 60 sequentially through a first through-hole in the environmental chamber 10. The environmental chamber 10 has a heating function. The controller 70 controls the charging and discharging device 30 to charge and discharge the lithium battery 80. When the state of charge of the lithium battery 80 reaches a preset charge range, the controller controls the environmental chamber 10 to heat at a preset rate to raise the temperature inside the sample chamber 20 to a first preset temperature threshold. The controller also controls the first solenoid valve 40 to open, allowing gas from the sample chamber 20 to enter the gas collection device 60. The controller also performs component analysis on the gas collected by the gas collection device 60 at different temperatures. The preset charge range, preset rate, and first preset temperature threshold can be determined according to actual conditions.

[0031] Specifically, in one embodiment of the present invention, the lithium battery 80 can be a single lithium-ion battery cell, and the lithium battery 80 can be placed in the sample chamber 20, which is made of steel plate, with a top cover ( Figure 2 The top cover (15) is removable and sealed to the main body of the compartment using a gasket. Pressure is applied using a nut. The gasket can withstand temperatures up to 200°C and can be made of silicone or graphite. For example, ... Figure 2 As shown, the sample chamber 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 cover 15 by welding. The interface located on the outer end of the cover 15 is directly connected to the charging and discharging device 30, and the interface located on the inner side of the chamber is connected to the positive and negative terminals of the lithium battery 80 respectively. In addition, the sample chamber cover 20 also has a thermocouple connection port, which is connected to the cover 15 by welding, and the cover 15 has two thermocouple connection interfaces (sample chamber internal temperature sensing interface 11 and lithium battery temperature sensing interface 12), one connected to the battery surface and the other placed in the space of the sample chamber 20, for monitoring the internal temperature of the sample chamber 20. The sample chamber 20 also has a first gas guide pipe 50, which is made of steel and welded to the sample chamber 20 for gas output.

[0032] The first gas delivery line 50 is connected sequentially to the first solenoid valve 40 and the gas collection device 60 through the first through hole of the environmental chamber 10. The first solenoid valve 40 can control the opening and closing of the first gas delivery line 50, so that when the first gas delivery line 50 is open, the gas collection device 60 can collect the gas in the sample chamber 20. The environmental chamber 10 has a high-temperature heating function, with a temperature range covering -20℃ to 200℃, a temperature rise rate of ≥5℃ / min, a temperature fluctuation of ≤0.5℃, and a temperature uniformity of ≤0.5℃. The environmental chamber 10 can be used to control the temperature of the sample chamber 20.

[0033] The lithium battery 80 is placed in the sample chamber 20, and the positive and negative terminals of the battery are connected to the charging interface and voltage monitoring interface inside the sample chamber 20. It can be connected to the charging / discharging device 30 via the charging interface, allowing the lithium battery 80 to be charged and discharged. To prevent adverse reactions between the lithium battery 80 and oxygen and water vapor during charging and discharging, thus ensuring the safety and accuracy of the test, the discharged lithium battery 80 and the sample chamber 20 can be placed in a glove environment. The glove environment requires an argon atmosphere with an oxygen content <1 ppm and a water content <1 ppm. The sample chamber cover 15 can be opened, and the lithium battery 80 placed in the sample chamber 20. The positive and negative terminals of the battery are connected to the charging interface and voltage monitoring interface inside the sample chamber 20, respectively. The thermocouple for monitoring temperature is also connected to the temperature monitoring interface on the cover 15. The thermocouple for monitoring battery temperature inside the sample chamber 20 is fixed to the center of the large surface of the individual battery using high-temperature resistant tape.

[0034] To prevent the lithium battery 80 from rupturing due to gas generation at high temperatures, a hole no larger than 1.5mm can be pre-punctured at the vent of the lithium battery 80 using a 1mm ceramic steel needle to allow the battery gas to escape from the inside. The hole is then sealed with high-temperature tape. The sample chamber cover 15 is then closed, and a nut is used to pressurize and seal the sample chamber 20. The sample chamber 20 is then removed from the glove box and placed in the environmental chamber 10 containing the lithium battery 80. The charging port and voltage monitoring port of the cover 15 are connected to the charging / discharging device 30. The first solenoid valve 40 is led out through the first through-hole of the environmental chamber 10 and placed outside the environmental chamber 10, remaining closed.

[0035] The controller 70 can activate 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%, to complete the lithium plating process of the lithium battery 80. In other words, by placing the lithium battery 80 under overcharge conditions, the lithium plating phenomenon is simulated.

[0036] When the state of charge of the lithium battery 80 reaches a preset charge range, the ambient chamber 10 can be controlled to heat at a preset rate to bring the temperature inside the sample chamber 20 to a preset temperature threshold, and the first solenoid valve 40 can be controlled to open to allow the gas inside the sample chamber 20 to enter the gas collection device 60. For example, the preset rate can be 5°C / min, and the preset temperature threshold can be 60 degrees Celsius. That is, by controlling the ambient chamber 10 to raise the temperature inside the sample chamber 20 from room temperature to 60 degrees Celsius at a rate of 5°C / min, the gas collection device 60 can collect the gas generated by the lithium battery 80 when thermal runaway has not occurred.

[0037] Once the preset temperature threshold is reached, heating can continue. A gradient heating method can be used, such as setting temperature steps in 5°C increments, starting at 60°C, with a heating rate of 5°C / min. This temperature is maintained for every 5°C increase in ambient temperature until the lithium battery 80 reaches ambient temperature for one hour, at which point the next 5°C temperature step is initiated, until the temperature reaches 200°C or the battery experiences thermal runaway. During this heating process, gas samples are collected at each temperature step to collect gases at different high temperatures. The gas collection device 60 can then analyze the composition of the gases collected at different temperatures. For example, the collected gases can be transferred to a gas chromatograph-mass spectrometer for compositional analysis to determine the type and concentration of thermally generated gases from the lithium battery 80 at different temperatures, and to analyze the thermal stability and gas generation characteristics of the lithium battery 80 at different temperatures. This provides a detailed understanding of the gas generation behavior of the lithium battery 80 under different states of charge and temperature conditions, offering crucial data support for the safe use and performance optimization of the battery.

[0038] According to one embodiment of the present invention, such as Figure 2 As shown, the testing equipment 100 for the thermal gas generation of lithium battery 80 further includes: a first three-way valve 42 and a vacuum device 44. The first three-way valve 42 is disposed on the first gas guide pipe 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 collection 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 (Not shown) It is also used to, during the process of controlling the vacuum pumping device 44 to be in the working state, control the first solenoid valve 40 to be in the 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, and after the vacuum pumping device 44 has been in operation for a first preset time, 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. The first preset time can be determined according to the actual situation.

[0039] Specifically, the first three-way valve 42 has three ports: a first port, a second port, and a third port. The first three-way valve 42 can control the gas flow direction, allowing gas to switch 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 gas in the test equipment, thereby ensuring that the collected gas is pure and can accurately simulate the gas production situation of the lithium battery 80 in actual use.

[0040] During the operation of the vacuuming device 44, the controller 70 first closes the first solenoid valve 40 to prevent gas from overflowing during the vacuuming process. It then connects the second and third ends of the first three-way valve 42, allowing gas to flow from the gas collection device 60 through the first gas guide pipe 50 and the first solenoid valve 40 to the vacuuming device 44, thus creating a vacuum inside the gas collection device 60 and the first gas guide pipe 50, placing the gas collection device 60 under negative pressure. After a preset operating time (e.g., 3 minutes), the controller connects the first and second ends of the first three-way valve 42. When the first solenoid valve 40 opens, the gas in the sample chamber 20 can be guided to the gas collection device 60 under negative pressure for gas collection and analysis.

[0041] According to one embodiment of the present invention, such as Figure 2 As shown, the testing equipment 100 for the thermal gas generation of the lithium battery 80 further includes: a second solenoid valve 82, a second gas guide pipe 84, and an inert gas storage device 86. The second gas guide pipe 84 is connected sequentially to the second solenoid valve 82 and the inert gas storage device 86 through a second through-hole in the environmental chamber 10. The controller 70 is further configured 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 testing equipment 100 for the thermal gas generation of the lithium battery 80 may further include a second solenoid valve 82, a second gas guide pipe 84, and an inert gas storage device 86. The second gas guide pipe 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 chamber 10. That is, the second gas guide pipe 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 entering the sample chamber 20. The inert gas storage device 86 is used to store inert gases, such as argon. Inert gases do not readily react chemically with other substances and are often used to create an oxygen-free or low-oxygen environment to prevent or reduce possible chemical reactions inside the lithium battery 80.

[0043] The controller 70 can control the second solenoid valve 82 to be in the open state, allowing the gas stored in the inert gas storage device 86 to enter the sample chamber 20. That is, when the second solenoid valve 82 is open, inert gas (such as argon) will enter the sample chamber 20 from the inert gas storage device 86 through the second gas guide pipe 84. This helps maintain a stable internal environment during testing, reducing oxidation or other chemical reactions that may affect the test results. Furthermore, by supplying argon gas into the sample chamber 20, the original gas distribution in the sample chamber 20 can be made more uniform, thereby improving the accuracy of the gas collected by the gas collection device 60.

[0044] According to one embodiment of the present invention, such as Figure 2 As shown, the testing equipment 100 for the thermal gas generated by the lithium battery 80 also includes a gas flow meter 88, which is installed on the second gas guide pipe 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.

[0045] Specifically, the testing equipment 100 for the thermally generated gas from the lithium battery 80 also includes a gas flow meter 88. The gas flow meter 88 is installed on the second gas delivery pipe 84 and connected to the inert gas storage device 86, 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 delivery pipe 84 to ensure that the gas enters the sample chamber 20 at a constant or adjustable rate. For example, the gas flow rate can be adjusted from 10 ml / min to 50 ml / min.

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

[0047] Specifically, the testing equipment 100 for the thermal gas generated by the lithium battery 80 also includes a second three-way valve 90. The second three-way valve 90 is a multi-port valve that controls the gas flow direction, allowing gas to switch between different ports, i.e., it has three ports: a first port, a second port, and a third port. The first port of the second three-way valve 90 is connected to a second solenoid valve 82, used to control the flow of inert gas (such as argon) from the inert gas storage device 86 to the sample chamber 20. The second port is connected to a gas flow meter 88, serving as the inert gas input port. The third port is connected to a vacuum device 44, used to extract gas when needed, creating or maintaining a vacuum environment.

[0048] During the process of controlling the vacuum pumping device 44 to be in working condition, the controller 70 also needs to control the second solenoid valve 82 to be in the 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 connect the third end of the second three-way valve 90 to evacuate the gas in the pipeline where the second solenoid valve 82, the second three-way valve 90 and the vacuum pumping device 44 are located. After a period of time, the controller can control the second end of the second three-way valve 90 to connect the third end of the second three-way valve 90 to evacuate 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, to prevent other gases from affecting the gas in the sample chamber 20 and to ensure the accuracy of the test results.

[0049] According to one embodiment of the present invention, the controller 70 is further configured to: after controlling the vacuum pumping device 44 to operate for a second preset time, control the inert gas storage device 86 to inject gas into the second gas guide pipe 84, and after injecting gas, control the vacuum device to operate again, control the second solenoid valve 82 to be closed, 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 pumping device 44 has been operating for a second preset time, for example, 3 minutes, the controller 70 can control the inert gas storage device 86 to inject gas into the second gas conduit 84. Injecting gas can more effectively expel the existing gas (such as air) from the conduit. After the gas is injected, the vacuum device can be controlled to operate again, and the second solenoid valve 82 can be closed. The first end of the second three-way valve 90 can be connected to the third end of the second three-way valve 90 to evacuate the gas in the conduit containing the second solenoid valve 82, the second three-way valve 90, and the vacuum pumping device 44. After a period of time, the second end of the second three-way valve 90 can be connected to the third end of the second three-way valve 90 to evacuate the gas in the conduit containing the inert gas storage device 86, the gas flow meter 88, the second three-way valve 90, and the vacuum pumping device 44, preventing other gases from affecting the gas in the sample chamber 20 and ensuring the accuracy of the test results. The above steps are repeated multiple times to complete the gas replacement of the pipeline.

[0051] According to one embodiment of the present invention, before placing the lithium battery 80 into the sample chamber 20, the controller 70 is also used to control the charging and discharging device 30 to adjust the lithium battery 80 to a depleted state.

[0052] Specifically, before placing the lithium battery 80 into the sample chamber 20, the SOC (State of Charge) of the individual lithium battery 80 cells can be adjusted to 0% to ensure that the lithium battery 80 is in a depleted state. This ensures that all tested lithium batteries 80 start from the same initial conditions, facilitating comparison of the performance and behavior of the lithium battery 80 under different test conditions. It also allows for better simulation and research of various situations that the lithium battery 80 may encounter in actual use, providing a known starting point for subsequent high-temperature tests or other types of tests, ensuring the accuracy and effectiveness of the tests.

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

[0054] Specifically, before controlling the charging / discharging device 30, the controller 70 also controls the ambient temperature inside the environmental chamber 10 to be below a second preset temperature threshold. This second preset temperature threshold can be -10°C. In other words, a lower ambient temperature inside the environmental chamber 10 makes lithium plating in the lithium battery 80 more pronounced. Specifically, at low temperatures, the chemical reaction rate inside the lithium battery 80 slows down, and the migration rate of lithium ions decreases, increasing the probability of lithium plating. This helps in studying and testing the battery's behavior under lithium plating conditions. For example, the temperature of the environmental chamber 10 can be adjusted from -20°C to 0°C, with a preferred temperature of -10°C (the second preset temperature threshold). The temperature of the lithium battery 80 is monitored until it reaches near the preferred temperature (e.g., between -10.5°C and -9.5°C), and this temperature range is maintained for more than one hour.

[0055] In summary, the lithium battery thermal gas generation testing equipment according to embodiments of the present invention includes a controller that controls the charging and discharging device to charge and discharge the lithium battery. When the lithium battery's state of charge reaches a preset range, the controller controls the environmental chamber to heat at a preset rate to raise the temperature inside the sample chamber to a preset temperature threshold. The controller also controls the first solenoid valve to open, allowing gas from the sample chamber to enter the gas collection device. Furthermore, the controller performs component analysis on the gas collected by the gas collection device at different temperatures. Therefore, this testing equipment enables the collection of gas from lithium batteries at different states of charge and temperatures, which is of great significance for improving lithium battery safety standards and promoting their safe use in various applications.

[0056] Corresponding to the above embodiments, the present invention also proposes a test method for thermal gas generation in lithium batteries.

[0057] like Figure 3 As shown, the testing method for thermal gas generation in lithium batteries according to embodiments of the present invention may include the following steps:

[0058] S1 adjusts the state of charge and 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, acquire the gas generated by the lithium battery at different ambient temperatures, and perform composition analysis based on the gas. The preset charge range and preset temperature threshold can be determined according to actual conditions.

[0060] Specifically, the state of charge (SOC) is a measure of the current charge level of a lithium battery, usually expressed as a percentage. Adjusting the SOC to a preset range means charging and discharging the battery until it reaches a specific level of charge, which serves as the starting point for testing. The temperature of a lithium battery can be controlled by placing it in a specific environmental chamber and adjusting the temperature to a preset threshold. Temperature has a significant impact on battery performance and chemical reactions. For example, a preset SOC range might be 100% to 120%, and a preset temperature threshold could be 60 degrees Celsius. When the SOC is within the preset range and the temperature reaches the preset threshold, lithium batteries may produce gases at specific ambient temperatures. These gases may include hydrogen, methane, carbon monoxide, etc., and their generation may be related to internal chemical reactions within the battery.

[0061] The temperature of the lithium battery can be continuously adjusted to obtain the gases produced by the lithium battery at different ambient temperatures. This can be achieved by using a gas collection device (such as a gas bag or gas cylinder) to collect the gases escaping from the lithium battery. The collected gases are then transferred to a gas chromatograph or other analytical equipment for component analysis to determine the types and concentrations of gases. This allows for a comprehensive evaluation of the performance and safety of the lithium battery under different ambient temperatures, 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 lithium battery thermal gas generation test method of the present invention, please refer to the details disclosed in the lithium battery thermal gas generation test device of the present invention, which will not be repeated here.

[0063] According to the present invention, a method for testing the thermally generated gas from a lithium battery involves adjusting the state of charge (SOC) and temperature of the lithium battery. When the SOC reaches a preset range and the temperature reaches a preset temperature threshold, the gas generated by the lithium battery at different ambient temperatures is acquired, and its composition is analyzed. Therefore, this method enables the collection of gas from lithium batteries at different SOCs and temperatures, 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 embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0065] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0066] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0068] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0069] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A testing device for thermal gas generation in lithium batteries, characterized in that, The device includes: an environmental chamber, a sample chamber, a charging / discharging device, a first solenoid valve, a first gas delivery pipeline, a gas collection device, and a controller. The lithium battery is placed inside the sample chamber, which is placed inside the environmental chamber. The sample chamber has a first gas delivery pipeline, which is connected sequentially to the first solenoid valve and the gas collection device through a first through-hole in the environmental chamber. The environmental chamber has a heating function. The controller is used to control the charging and discharging device to charge and discharge the lithium battery, so that when the state of charge of the lithium battery reaches the preset state of charge range, the controller controls the environmental chamber to heat at a preset rate so that the temperature in the sample chamber reaches a first preset temperature threshold, and controls the first solenoid valve to be in the open state so that the gas in the sample chamber enters the gas collection device, and performs component analysis on the gas collected by the gas collection device at different temperatures. The device further includes: a first three-way valve and a vacuum pumping device. The first three-way valve is disposed on the first gas guide pipe. 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 collection device, and the third end of the first three-way valve is connected to the vacuum pumping device. The controller is further configured to: control the first solenoid valve to be closed 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 operation of the vacuum pumping device; 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 operating for a first preset time. The controller is further configured to continue heating when the first preset temperature threshold is reached. The heating adopts a gradient heating method to generate multiple temperature steps. The corresponding temperature is maintained at each temperature step until the temperature of the lithium battery is consistent with the temperature of the environmental chamber for one hour, and then the next temperature step is started until 200°C is reached or the lithium battery experiences thermal runaway. After each temperature step is completed, the first solenoid valve is controlled to be in the open state so that the gas in the sample chamber can enter the gas collection device, and the composition analysis is performed on the gas collected by the gas collection device at different temperatures.

2. The testing equipment for thermal gas generation in lithium batteries according to claim 1, characterized in that, Also includes: The system comprises a second solenoid valve, a second gas delivery pipeline, and an inert gas storage device, wherein the second gas delivery pipeline is sequentially connected to the second solenoid valve and the inert gas storage device through a second through-hole in the environmental chamber; 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 enters the sample chamber.

3. The testing equipment for lithium battery thermal gas generation according to claim 2, characterized in that, Also includes: A gas flow meter is installed on the second gas guide pipe and connected to the inert gas storage device to adjust the flow rate of gas entering the sample chamber.

4. The testing equipment for lithium battery thermal gas generation according to claim 3, characterized in that, Also includes: The second three-way valve has its first end connected to the second solenoid valve, its second end connected to the gas flow meter, and its third end 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 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.

5. The testing equipment for lithium battery thermal gas generation according to claim 4, characterized in that, The controller is also used for: After controlling the vacuum device to operate for a second preset time, the inert gas storage device is controlled to inject gas into the second gas pipeline. After the gas is injected, the vacuum device is controlled to operate again, the second solenoid valve is controlled to be closed, the first end of the second three-way valve is connected to the third end of the second three-way valve, and the second end of the second three-way valve is connected to the third end of the second three-way valve.

6. The testing equipment for thermal gas generation in lithium batteries according to any one of claims 2-5, characterized in that, The inert gas storage device stores argon gas.

7. The testing equipment for thermal gas generation in lithium batteries according to claim 1, characterized in that, Before placing the lithium battery into the sample chamber, the controller is also used to control the charging and discharging device to adjust the lithium battery to a depleted state.

8. The testing equipment for thermal gas generation in lithium batteries according to claim 1, characterized in that, Before controlling the charging and discharging device, the controller is also used to control the ambient temperature inside the environmental chamber to be lower than a second preset temperature threshold.

9. A test method for a lithium battery thermal gas generation test device based on any one of claims 1-8, characterized in that, The method includes: Adjust the state of charge and temperature of the lithium battery; 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 of the gas is analyzed.

Images