Immersed battery thermal safety management test system and method

Abstract

The invention provides an immersed battery thermal safety management test system and method, and the system comprises a battery device disposed in an immersion box, and an immersed cooling structure is built through assembly combination. The liquid cooling circulation module is used for driving cooling liquid to flow; the charging and discharging module is used for performing a charging and discharging test or a thermal safety performance test on the battery device; the needling module is used for needling to trigger the working condition of thermal runaway; the electric control module is in signal connection with the liquid cooling circulation module, and monitors and adjusts the flow, the water temperature and the water pressure of the cooling liquid in the liquid cooling circulation module in real time; the data acquisition module is used for acquiring temperature and voltage change characteristics of the battery device; through the system and the method, thermal performance and safety performance tests can be carried out, the test requirements of different types of batteries under various working conditions can be met, the thermal performance and safety of the battery immersed liquid cooling system can be accurately evaluated under various complex working conditions, and powerful data support is provided for thermal management design and optimization of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery thermal management, and in particular to an immersion battery thermal safety management test system and method. Background Art

[0002] With the rapid development of electric vehicles, energy storage devices and portable electronic devices, lithium-ion batteries have become the mainstream energy storage technology. Lithium batteries are widely used in various electric products due to their high energy density, long cycle life and efficient charging and discharging capabilities. However, when lithium-ion batteries are discharged at high power, charged quickly or physically damaged externally, they are prone to a sharp rise in internal temperature, leading to thermal runaway, and even fire or explosion in severe cases. In order to solve the problem of battery thermal management and ensure the safety of batteries in different working environments, researching and developing efficient thermal management systems has become one of the technical problems that need to be solved urgently.

[0003] Existing battery thermal management methods mainly include air cooling, liquid cooling and phase change material cooling. Among them, liquid cooling technology has gradually attracted widespread attention due to its good heat dissipation performance, especially immersion liquid cooling. By directly immersing the battery in high-efficiency coolant, the liquid can quickly take away the heat generated on the battery surface, effectively reduce the battery temperature, and prevent the occurrence of thermal runaway. However, although immersion liquid cooling has significant advantages in improving heat dissipation efficiency, the current thermal performance and safety testing methods for immersion liquid cooling systems are still imperfect.

[0004] Existing battery thermal management test systems are mostly based on air cooling or surface liquid cooling, and lack targeted testing solutions for immersion liquid cooling systems. The current immersion test method cannot fully simulate the thermal behavior of batteries under multiple working conditions, multiple cooling structures, and multiple thermal management strategies, and it is difficult to accurately evaluate the cooling effect of immersion liquid cooling and its improvement on battery thermal (safety) performance. For example, China Patent Publication No. CN212007678U discloses a new type of battery immersion test box, the main purpose of which is to improve the accuracy of battery waterproof testing; China Patent Publication No. CN114216923A provides a power battery system ice water impact immersion test device, which is mainly used for ice water impact immersion testing of battery systems. Both of the above patents cannot meet the thermal (safety) performance test requirements of batteries in an immersed state. Therefore, there is an urgent need for an innovative test method and system that can accurately evaluate the thermal performance and safety of battery immersion liquid cooling systems under a variety of complex working conditions, and provide strong data support for battery thermal management design and optimization. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a system and method that can cover various operating conditions of the battery, support the customized construction of different immersion cooling solutions, and perform thermal performance and safety performance testing.

[0006] To achieve the above object, the present invention provides an immersion battery thermal safety management test system, the test system comprising a battery device, the battery device is arranged in an immersion box, and an immersion cooling structure is formed in the immersion box by combining components;

[0007] The test system also includes the following modules:

[0008] Liquid cooling circulation module: used to drive the flow of cooling liquid to take away the heat generated by the battery device and reduce the temperature of the battery device;

[0009] Charge and discharge module: used to perform charge and discharge test or thermal safety performance test on the battery device, so as to evaluate the battery performance;

[0010] Acupuncture module: used for triggering a thermal runaway condition by acupuncture of the battery device;

[0011] Electronic control module: connected to the liquid cooling circulation module by signal, used for real-time monitoring and adjusting the flow rate, water temperature and water pressure of the coolant in the liquid cooling circulation module;

[0012] Data acquisition module: used to acquire the temperature and voltage variation characteristics of the battery device.

[0013] Furthermore, the immersion box includes a box cover and a box body: a sealing gasket is provided between the box cover and the box body, and the box cover and the box body are fixed by bolts; a plurality of through holes are distributed on the box cover and the box body, and when the through holes are not used, the through holes are closed by removable threaded plugs; in the acupuncture module, the through holes used for acupuncture are closed by rubber plugs instead of threaded plugs.

[0014] Furthermore, researchers can customize the layout inside the box based on a pre-designed immersion liquid cooling solution.

[0015] Furthermore, in the liquid cooling circulation module, the flow direction of the coolant is: valve → flow meter → water pump → expansion kettle → heat exchange device → sensor A → immersion tank → sensor B → valve; the valve is used to control the on and off of the coolant to start or stop the liquid cooling circulation module; the valve is also used to adjust the flow rate and flow of the coolant through valve opening control to meet the cooling or heat transfer requirements under different working conditions; the flow meter is used to monitor the flow of the coolant in real time and feed it back to the electronic control module, so that the electronic control module controls the valve opening and the water pump voltage to adjust the flow of the coolant to ensure that the test system operates according to the set requirements; the water pump mainly provides energy for the liquid , used to drive the coolant to flow in the test system, ensuring that the coolant can circulate at the set pressure and flow rate; the expansion kettle is used to absorb and accommodate the volume change caused by the heat expansion of the coolant in the liquid-cooled circulation module, ensuring the safe and stable operation of the test system; the A sensor and the B sensor are respectively used to monitor the temperature and pressure of the coolant on both sides of the immersion tank in the liquid-cooled circulation module; and feed back to the electronic control module; the heat exchange device includes a heat exchanger and a constant temperature bath, the heat exchanger and the constant temperature bath are connected to form a branch to realize heat exchange between different media, which is used to cool or heat the coolant, thereby realizing the temperature control of the coolant.

[0016] Furthermore, the sensor is arranged on the surface of each battery at a position equidistant from the positive and negative poles and closest to the positive and negative poles.

[0017] Furthermore, the charging and discharging module includes a charging and discharging instrument connected to the battery device, and the charging and discharging instrument is used for conventional charging and discharging tests under constant current, constant voltage and dynamic conditions, or for thermal safety performance tests such as overcharging and overdischarging, so as to achieve different charging and discharging conditions.

[0018] Furthermore, the acupuncture module uses a needling machine to push a steel needle through the rubber plug of the immersion box to puncture the corresponding battery to achieve the acupuncture operation; specifically, after the battery or battery module in the battery device determines the acupuncture position, the corresponding plug on the side of the immersion box body is removed and replaced with a rubber plug, and the parameters such as the diameter, puncture speed and puncture depth of the steel needle are set, and the acupuncture machine is used to push the steel needle through the rubber plug to complete the acupuncture operation.

[0019] Furthermore, the electronic control module is respectively connected to the flow meter, sensor A, sensor B, valve, water pump and heat exchange device for real-time monitoring and adjusting the flow rate, water temperature and water pressure of the coolant in the liquid cooling circulation module; specifically: on the one hand, the electronic control module monitors the key parameters such as the flow rate, water temperature and water pressure in the liquid cooling circulation module in real time through the flow meter and sensors A and B to ensure that each device operates within the normal working range; on the other hand, by controlling the opening of the valve and the voltage of the water pump, the flow rate of the coolant is accurately adjusted, and the temperature of the coolant is controlled by the constant temperature bath in the heat exchange device, so as to realize different thermal management strategies and meet the needs of specific working conditions. The electronic control module is also used to control the start and stop of the test system to realize different thermal management strategies.

[0020] Furthermore, the data acquisition module is used to collect the changing characteristics of key parameters such as temperature and voltage of the battery device; the data acquisition module uses a data acquisition instrument and is connected to the battery device through a battery temperature monitoring line and a voltage monitoring line; the battery temperature monitoring line and the voltage monitoring line are led out from the immersion box, and the voltage monitoring line is arranged at the positive and negative poles of each battery.

[0021] Furthermore, the battery device is a battery or a battery module, and the battery types include soft-pack batteries and square batteries, and also include ternary material batteries and lithium iron phosphate batteries.

[0022] Furthermore, the immersion box containing the battery device is placed in a high and low temperature constant temperature box, and the high and low temperature constant temperature box is used to simulate different environmental temperatures during the test process.

[0023] The present invention also proposes an immersion battery thermal safety management test method. Based on the above immersion battery thermal safety management test system, the test method comprises the following steps:

[0024] S1: Input battery information, including battery model, size, capacity and operating voltage;

[0025] S2: Determine the operating conditions of the battery, including conventional cooling conditions and thermal safety test conditions; conventional cooling conditions include constant charging and discharging conditions and diversified dynamic conditions; thermal safety test conditions include thermal runaway characteristics test and thermal runaway diffusion performance test;

[0026] S3: Design immersion liquid cooling solutions and formulate thermal management strategies, including static immersion, dynamic immersion, and immersion modes with coordinated temperature control of static and dynamic;

[0027] S4: According to the immersion liquid cooling solution, an immersion cooling structure is built in the immersion tank;

[0028] S5: According to the immersion liquid cooling solution, remove the threaded plug at the appropriate position of the box cover and replace it with an explosion-proof valve;

[0029] S6: setting the boundary conditions of the test, wherein the boundary conditions include environment, coolant flow rate and coolant inlet temperature parameters;

[0030] S7: Turn on the test system and conduct a thermal safety performance test.

[0031] Furthermore, in step S4, necessary components such as filling blocks, thermal insulation materials, and supporting pads are combined with specific components to build an immersion cooling structure in the immersion tank. It should be noted that: when customizing the inlet and outlet positions of the coolant, the plug on the side of the immersion tank can be removed and replaced with a pagoda connector to connect the liquid cooling circulation loop of the liquid cooling circulation module; when arranging the charging and discharging lines, voltage monitoring lines, and temperature monitoring lines of the battery module, it is also necessary to remove the side plug, and after the wiring harness passes through the through hole, use sealant to seal the hole to prevent leakage.

[0032] Compared with the prior art, the advantages of the present invention are:

[0033] 1. The present invention can perform thermal and safety performance tests by setting up a charging and discharging module, a puncture module and an electronic control module, and can meet the testing requirements of different types of batteries under various working conditions. The battery types mainly include batteries of different shapes and positive electrode materials, such as soft packs, square batteries, ternary materials, lithium iron phosphate, etc.; the various working conditions cover conventional cooling conditions and thermal safety experimental conditions; the present invention can accurately evaluate the thermal performance and safety of the battery immersion liquid cooling system under various complex working conditions, and provide strong data support for battery thermal management design and optimization.

[0034] 2. The present invention monitors and adjusts the flow rate, water temperature and water pressure of the coolant in the liquid cooling circulation module in real time through the signal connection between the liquid cooling circulation module and the electronic control module, and realizes a variety of thermal management strategies, mainly including static immersion, dynamic immersion, and immersion mode of dynamic and static coordinated temperature control. Based on the test data, researchers can further analyze and optimize the flow strategy of the coolant.

[0035] 3. The present invention places the battery device in an immersion box, uses components combined inside the immersion box to customize the cooling structure required for testing, flexibly selects the inlet and outlet positions of the coolant, and freely arranges the inlet and outlet of the wiring harness, thereby completing the testing of different immersion cooling structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of an immersion battery thermal safety management test system according to an embodiment of the present invention;

[0037] Figure 2 It is a structural schematic diagram of an immersion box in an immersion battery thermal safety management test system according to an embodiment of the present invention;

[0038] Figure 3A flow chart of a thermal safety management test method for an immersed battery according to an embodiment of the present invention;

[0039] Figure 4 A schematic diagram of an immersion liquid cooling structure provided in Experiment 1 of the present invention;

[0040] Figure 5 A top view of an immersion liquid cooling structure provided in Experiment 1 of the present invention with the box cover removed;

[0041] Figure 6 A cross-sectional view of an immersion liquid cooling structure at AA provided in Example 1 of the present invention;

[0042] Figure 7 A schematic diagram of an immersion liquid cooling structure provided for Experiment 2 of the present invention;

[0043] Figure 8a and Figure 8b This is a curve diagram of the battery module temperature and temperature difference changes at different discharge rates in Experiment 1;

[0044] Figure 9a and Figure 9b They are respectively the curves of the battery module temperature and voltage changes under the needle puncture thermal runaway diffusion performance test in Experiment 2;

[0045] In the figure: 1. valve; 2. flow meter; 3. water pump; 4. expansion kettle; 5. heat exchanger; 6. sensor A / 14, sensor B; 7. battery or module; 8. immersion box; 9. high and low temperature constant temperature box; 10. constant temperature bath; 11. battery charging and discharging instrument; 12. acupuncture machine; 13. electronic control module; 15. data acquisition instrument

[0046] 801. Box cover; 802. Box body; 803. Sealing gasket; 804. Plug; 805. Box body through hole; 806. Explosion-proof valve through hole; 807. Threaded fixing hole; 808. Fixed through hole; 809. Explosion-proof valve; 810. Large filling block; 811. Medium filling block; 812. Small filling block; 813. Insulation material; 814. Support pad; 815. Battery module; 816. Support bar; 817. Voltage stabilizing block; 818. Pagoda joint; 819. Rubber plug; 820. Steel needle. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described below.

[0048] This embodiment provides an immersion battery thermal safety management test system. Figure 1As shown, the test system includes a battery device 7, a liquid cooling circulation module, a charging and discharging module, a needle puncture module, an electronic control module and a data acquisition module, wherein the battery device 7 is arranged in an immersion box 8, and an immersion cooling structure is built in the immersion box 8 by combining components; the immersion box 8 loaded with the battery device 7 is placed in a high and low temperature constant temperature box 9, and the high and low temperature constant temperature box 9 is used to simulate different ambient temperatures during the test process; the liquid cooling circulation module and the immersion box 8 form a closed loop; it is used to drive the coolant to flow along the direction of valve 1→flow meter 2→water pump 3→expansion kettle 4→heat exchanger 5→A sensor 6→immersion box 8→B sensor 14→valve 1, thereby taking away the heat generated by the battery device 7 and reducing the temperature of the battery device 7; in the charging and discharging module, a battery charging and discharging instrument 11 is used to connect with the battery device 7, which is used to perform conventional charging and discharging tests on the battery device 7 under constant current and constant voltage and dynamic conditions or for thermal safety such as overcharging and over-discharging. The battery device 7 can be tested to achieve different charging and discharging conditions and evaluate the battery performance; the acupuncture module performs acupuncture treatment on the battery device 7 through the acupuncture machine 12, thereby triggering the thermal runaway condition; the electronic control module is connected to the liquid cooling circulation module signal through the electronic control center 13, which is used to monitor and adjust the flow rate, water temperature and water pressure of the coolant in the liquid cooling circulation module in real time; specifically: on the one hand, the electronic control module monitors the key parameters such as the flow rate, water temperature and water pressure in the liquid cooling circulation module in real time through the flow meter 2 and the sensor (A sensor 6 and B sensor 14) to ensure that each device operates within the normal working range; on the other hand, by controlling the opening of the valve 1 and the voltage of the water pump 3, the flow rate of the coolant is accurately adjusted, and the temperature of the coolant is controlled by the constant temperature bath 10 in the heat exchange device, so as to realize different thermal management strategies and meet the needs of specific working conditions; at the same time, the electronic control module is also used to control the start and stop of the test system to realize different thermal management strategies. The data acquisition module is used to collect the changing characteristics of key parameters such as temperature and voltage of the battery device 7; the data acquisition module uses a data acquisition instrument 15, which is connected to the battery device 7 by leading out the battery temperature monitoring line and voltage monitoring line from the immersion box 8; wherein the voltage monitoring line is arranged at the positive and negative poles of each battery.

[0049] In the liquid cooling circulation module, valve 1 is used to control the on and off of the coolant to start or stop the liquid cooling circulation module; it is also used to adjust the flow rate and flow of the coolant through the opening control of valve 1 to meet the cooling or heat transfer requirements under different working conditions; flow meter 2 is used to monitor the flow of the coolant in real time and feed it back to the electronic control module, so that the electronic control module can adjust the flow of the coolant by controlling the valve opening and the water pump voltage to ensure that the test system operates according to the set requirements; water pump 3 mainly provides energy for the liquid, which is used to drive the coolant to flow in the test system to ensure that the coolant can circulate according to the set pressure and flow rate; expansion The kettle 4 is used to absorb and contain the volume change caused by the heat expansion of the coolant in the liquid cooling circulation module, so as to ensure the safe and stable operation of the test system; the A sensor 6 and the B sensor 14 are respectively arranged on the surface of each battery at a position equidistant from the positive and negative poles and closest to the positive and negative poles, and are used to monitor the temperature and pressure of the coolant on both sides of the immersion tank 8 in the liquid cooling circulation module; and feed back to the electronic control module; the heat exchange device includes a heat exchanger 5 and a constant temperature bath 10, wherein the heat exchanger 5 and the constant temperature bath 10 are connected to form a branch to realize heat exchange between different media, which is used to cool or heat the coolant, thereby realizing the temperature control of the coolant.

[0050] In addition, if Figure 2 As shown, the immersion box 8 includes a box cover 801 and a box body 802, and a sealing gasket 803 is installed between the two to prevent liquid leakage; the bolts are passed through the fixing through holes 808 on the box cover 801 and fixed to the corresponding threaded fixing holes 807 on the box body 802; the immersion box 8 is provided with a plurality of box body through holes 805 and box cover through holes 806, and when the box body through holes 805 and the box cover through holes 806 are not in use, these through holes are closed by removable threaded plugs 804; in the acupuncture module, the through holes used for acupuncture are closed with rubber plugs 819 instead of threaded plugs 804.

[0051] The immersion battery thermal safety management test system proposed in this embodiment is used to perform thermal safety performance tests, such as Figure 3 As shown, the specific steps of the test method are as follows:

[0052] S1: Input battery information such as model, size, capacity and operating voltage.

[0053] S2: Determine the operating conditions of the battery, covering conventional cooling conditions and thermal safety test conditions; among them, conventional cooling conditions include constant charging and discharging conditions and diversified dynamic conditions; thermal safety test conditions involve thermal runaway characteristic tests and thermal runaway diffusion performance tests.

[0054] S3: Develop thermal management strategies, which mainly include static immersion, dynamic immersion, and immersion modes with coordinated temperature control between static and dynamic.

[0055] S4: According to the immersion liquid cooling solution, the immersion cooling structure is built in the immersion box by using necessary components such as filling blocks 810-812, insulation materials 813, support pads 814 and specific components 816-817. It should be noted that: when customizing the coolant inlet and outlet positions, the plug 804 on the side of the immersion box can be removed and replaced with a pagoda connector 818 to connect the liquid cooling circulation loop; when arranging the charging and discharging lines, voltage monitoring lines and temperature monitoring lines of the battery module 815, it is also necessary to remove the side plug 804, and after the wiring harness passes through the through hole 805, use sealant to seal the hole to prevent leakage.

[0056] S5: According to the immersion liquid cooling solution, remove the plug 804 at the appropriate position of the box cover 801 and replace it with the explosion-proof valve 809.

[0057] S6: Set the boundary conditions of the test, including parameters such as environment, coolant flow rate and coolant inlet temperature.

[0058] S7: Start the test system and conduct thermal safety performance test.

[0059] Experiment 1

[0060] Using the immersion battery thermal safety management test system and test method provided in the above embodiment, the test of Experiment 1 is carried out to test the thermal performance of an energy storage battery module under immersion flow state. This Experiment 1 is specifically as follows: the battery module 815 is discharged at a rate of 0.5C and 1C. During the test, the coolant inlet temperature is kept the same as the ambient temperature at 25°C, and the coolant flow rate is 0.5L / min.

[0061] In Experiment 1, Figure 4 As shown, the battery device 7 is a battery module 815 composed of five 100Ah lithium iron phosphate battery cells LF100LA of Yiwei in series. The battery module 815 is arranged in the immersion box 8 and immersed in the coolant. The coolant is Yundong SH-07 produced by Lu'an Taihang Lubrication Technology Co., Ltd., and its related thermophysical property parameters are detailed in Table 1:

[0062] Table 1 Thermophysical properties of Yundong SH-07 coolant at 20℃

[0063]

[0064] The battery module 815 is placed in the immersion box 8, and an immersion cooling structure is built in the immersion box 8, such as Figure 4-6As shown, the immersion cooling structure is specifically arranged as follows: the battery module 815 is composed of 1#-5# batteries connected in series, and the battery module 815 is covered with a heat insulating material 813 to reduce the heat transfer loss to the outside when the battery module 815 is working. The heat insulating material 813 can be selected but not limited to aerogel; the bottom of the battery module 815 is provided with a support bar 816, so as to form a smooth flow channel at the bottom of the battery; the front end of the battery module 815 (on the X-axis) is also provided with a voltage stabilizing block 817, which is used to make the flow distribution of multiple flow channels in the bottom flow channel of the battery module 815 more uniform during current collection, and also prevent the coolant from escaping upward in large quantities due to the large gap between the front end of the battery module 815 and the box 802; Figure 4-6 As shown, the remaining space in the immersion box 8 is filled with filling blocks 810-812, similar to the way of building blocks. The filling blocks used are divided into three specifications: large 810, medium 811, and small 812. The main functions of the filling blocks 810-812 are two: one is to fix the battery module 815, and the other is to reduce the amount of coolant used, thereby reducing costs; install an explosion-proof valve 809 on the box cover 801 on the top of the battery module 815, and replace the first plug 804 on the left side of the box cover 801 with an explosion-proof valve 809, so as to release pressure in time in the event of sudden thermal runaway and reduce the risk of explosion. It should be noted that when customizing the immersion cooling structure in the immersion box 8, components that are used in different immersion schemes, such as filling blocks 810-812, insulation materials 813, and support pads 814, are called necessary components; components such as support bars 816 and voltage stabilizing blocks 817 that are only used in this embodiment are called specific components.

[0065] At the same time, the inlet and outlet of the coolant are set in front of the battery module 815, and the first and fourth plugs 804 on the small side of the left side of the box body 802 are replaced from top to bottom, and converted into a pagoda joint 818 to connect with the liquid cooling circulation loop, so as to realize a flow mode of inlet from the bottom and outlet from the top; Figure 6 As shown, the coolant inlet must be aligned with the flow channel at the bottom of the module 815. To this end, the bottom of the module 815 is padded with multiple layers of high temperature resistant support pads 814 to ensure that this requirement is met. In addition, the adjacent batteries in the battery module 815 are connected by slender spacers to form a smooth flow channel up and down. Therefore, the specific flow route of the coolant in the immersion tank is as follows: inlet → bottom of the battery module → large surface and side of the battery → top of the battery module → outlet. In addition, as Figure 5 As shown, the charge and discharge lines, voltage monitoring lines and temperature monitoring lines of the battery module 815 are led out through the through hole 805 on the large side of the rear side of the box 802 and connected to the data acquisition instrument 13. Subsequently, the through hole is sealed with a sealant to prevent liquid leakage. The sensor is arranged on the surface of each battery at a position equidistant from the positive and negative poles and closest to the positive and negative poles; the voltage monitoring line is arranged at the positive and negative poles of each battery.

[0066] The test results of Experiment 1 are shown in Figure 8. It can be seen from Figure 8 that as the discharge progresses, the maximum temperature and temperature difference of the battery module in this Example 1 both show a gradual upward trend. At the end of the 0.5C discharge, the temperature and temperature difference of the battery module reached a maximum value of 32.3°C and 1.8°C; at the end of the 1C discharge, the maximum temperature and temperature difference were 37.1°C and 2.9°C. The maximum temperature of the module is lower than 40°C, and the maximum temperature difference is lower than 5°C. Therefore, through the submerged battery thermal safety management test system and method provided in this embodiment, it is detected that the submerged cooling structure constructed in Experiment 1 has good temperature control capabilities.

[0067] Example 2

[0068] Using the immersion battery thermal safety management test system and test method provided in the above embodiment, the test of Experiment 2 is carried out to test the thermal runaway diffusion performance of a power battery module under immersion and non-flowing state. The specific contents of Experiment 2 are:

[0069] In Experiment 2, the battery module 815 is composed of four 151Ah ternary batteries (NCM622) of the CATL. The battery module is immersed in the coolant. The selected coolant is Yundong SH-03 produced by Lu'an Taihang Lubrication Technology Co., Ltd. The relevant thermophysical property parameters are detailed in Table 2.

[0070] Table 2 Thermophysical properties of Yundong SH-03 coolant at 20℃

[0071]

[0072] In Experiment 2, the battery module 815 is immersed in the immersion tank to build a cooling structure such as Figure 7 As shown, 1#-4# ternary batteries are connected in series to form a battery module 815, wherein 2# ternary battery is used as a thermal runaway trigger battery, and the acupuncture position is set at the center of the side of the battery. The acupuncture orientation selects the center position of the large side of the front side of the box 802, so it is necessary to remove the plug in the middle of the second vertical row on the front side of the box 802 and replace it with a rubber plug 819. The rubber plug 819 is not only convenient for the puncture of the steel needle 820, but also can elastically cover the steel needle 820, thereby reducing the leakage of the coolant. After replacing the rubber plug 819, set the parameters such as the diameter, acupuncture speed and acupuncture depth of the steel needle 820, and use the acupuncture machine 12 to push the steel needle 820 through the rubber plug 819 to complete the acupuncture operation.

[0073] In Experiment 2, Figure 7As shown, a multi-layer high temperature resistant support pad 814 is provided at the bottom of the battery module 815 to ensure that the 2# ternary battery is accurately aligned with the steel needle 820. Except for the puncture surface, the other three sides of the battery module 815 are covered with insulation material 813 to reduce the loss of heat transferred to the outside during the test. The insulation material 813 can be selected but not limited to aerogel. In addition, the outside of the insulation material 813 is filled with filling blocks 810-812 of different specifications to fix the battery and reduce the amount of coolant, such as Figure 7 As shown, the left and right sides (X-axis direction) of the battery module 815 and the box body 802 are filled with symmetrical medium-sized filling blocks 811, and the rear side of the battery module 815 is filled with large filling blocks 810.

[0074] At the same time, in Experiment 2, Figure 7 As shown, the voltage monitoring line and temperature monitoring line of the battery module 815 are led out through the wiring hole 805 on the large side of the rear side of the box body 802, and connected to the data acquisition instrument 13. Subsequently, the through hole is sealed with a sealant to prevent liquid leakage. Furthermore, the temperature sensor is arranged on the surface of each battery at a position equidistant from the positive and negative poles and closest to the positive and negative poles according to GB36276-2023; the voltage monitoring line is arranged at the positive and negative poles of each battery.

[0075] In Experiment 2, the inlet of the coolant is located at the middle of the upper part of the small side surface on the left side of the box 802, and the outlet is located at the lower right side of the large side surface 820 on the front side of the box 802. The inlet and outlet are connected to the liquid cooling circulation loop after replacing the pagoda connector 818. Since Experiment 2 adopts the immersion non-flow mode, after the immersion box 8 is filled with liquid in the liquid cooling circulation module, the valve 1 and the water pump 3 are closed, and the coolant stops flowing.

[0076] In this experiment 2, after replacing the rubber plug 819, the 2# ternary battery was punctured at a speed of 25±5mm / s to trigger thermal runaway. The diameter of the steel needle 820 was 8mm, the cone angle was 45°, the puncture depth was about 10cm, and the ambient temperature was 35℃ to simulate the hot summer. The test results are as follows Figure 9a and Figure 9b As shown, from Figure 9a and Figure 9b The test results show that the thermal runaway phenomenon of battery module 815 spreads in the immersed state, and the spreading order is as follows: 2#→1#→3#→4#. Among them, the temperature of battery 1# during thermal runaway is the highest, reaching 643.7℃, and the highest temperatures of the remaining batteries are also above 300℃. Figure 9bIt can be seen that 175s, 184s and 417s after the voltage of the 2# needle-punctured battery dropped, the 1#, 3# and 4# batteries also experienced thermal runaway successively, and their voltages all dropped rapidly to 0 V. Therefore, it can be concluded that through the detection of the immersion battery thermal safety management test system and method of this embodiment, it can be found that when the needle puncture triggers thermal runaway, Experiment 2 failed to successfully prevent the spread of thermal runaway in the ternary power battery module.

[0077] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. An immersion battery thermal safety management test system, characterized in that: The test system comprises a battery device, which is arranged in an immersion tank and is built in the immersion tank by combining components to form an immersion cooling structure; the test system also comprises: Liquid cooling circulation module: used for driving the flow of cooling liquid to reduce the temperature of the battery device; Charge and discharge module: used to perform charge and discharge test or thermal safety performance test on the battery device, so as to evaluate the battery performance; Acupuncture module: used for triggering a thermal runaway condition by acupuncture of the battery device; Electronic control module: connected to the liquid cooling circulation module by signal, used for real-time monitoring and adjusting the flow rate, water temperature and water pressure of the coolant in the liquid cooling circulation module; Data acquisition module: used to acquire the temperature and voltage variation characteristics of the battery device.

2. The submerged battery thermal safety management test system according to claim 1, characterized in that: The immersion box includes a box cover and a box body: a sealing gasket is arranged between the box cover and the box body, through holes are distributed on the box cover and the box body, and the through holes are closed by detachable threaded plugs; in the acupuncture module, the through holes used for acupuncture are closed by rubber plugs.

3. The submerged battery thermal safety management test system according to claim 1, characterized in that: In the liquid cooling circulation module, the flow direction of the coolant is: valve → flow meter → water pump → expansion kettle → heat exchange device → sensor A → immersion tank → sensor B → valve; the valve is used to control the on / off, flow rate and flow of the coolant; the flow meter is used to monitor the flow of the coolant in real time and feed it back to the electronic control module; the water pump is used to drive the coolant to flow; The expansion kettle is used to absorb and contain the volume change caused by the heat expansion of the coolant in the liquid cooling circulation module; the A sensor and the B sensor are used to monitor the temperature and pressure of the coolant on both sides of the immersion tank in the liquid cooling circulation module respectively; And feed back to the electronic control module; the heat exchange device includes a heat exchanger and a constant temperature bath, the heat exchanger and the constant temperature bath are connected to cool or heat the coolant.

4. The submerged battery thermal safety management test system according to claim 1, characterized in that: The charge and discharge module includes a charge and discharge instrument connected to the battery device, and the charge and discharge instrument is used for conventional charge and discharge tests under constant current, constant voltage and dynamic conditions, or for thermal safety performance tests such as overcharge and overdischarge.

5. The submerged battery thermal safety management test system according to claim 2, characterized in that: The acupuncture module uses a needle punching machine to push a steel needle through the rubber plug of the immersion box to puncture the corresponding battery to achieve the acupuncture operation.

6. The submerged battery thermal safety management test system according to claim 3, characterized in that: The electronic control module is respectively connected to the flow meter, A sensor, B sensor, valve, water pump and heat exchange device for real-time monitoring and adjustment of the flow rate, water temperature and water pressure of the coolant in the liquid cooling circulation module; the electronic control module is also used to control the start and stop of the test system to achieve different thermal management strategies.

7. The submerged battery thermal safety management test system according to claim 1, characterized in that: The data acquisition module uses a data acquisition instrument and is connected to the battery device through a battery temperature monitoring line and a voltage monitoring line.

8. The submerged battery thermal safety management test system according to claim 1, characterized in that: The battery device is a battery or a battery module, and the battery types include soft-pack batteries and square batteries, as well as ternary material batteries and lithium iron phosphate batteries.

9. The submerged battery thermal safety management test system according to claim 2, characterized in that: The immersion box is placed in a high and low temperature constant temperature box, and the high and low temperature constant temperature box is used to simulate different environmental temperatures during the test process.

10. A method for testing thermal safety management of a submerged battery, based on the system for testing thermal safety management of a submerged battery as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1: Input battery information, including battery model, size, capacity and operating voltage; S2: Determine the operating conditions of the battery, including conventional cooling conditions and thermal safety test conditions; conventional cooling conditions include constant charging and discharging conditions and diversified dynamic conditions; thermal safety test conditions include thermal runaway characteristics test and thermal runaway diffusion performance test; S3: Design immersion liquid cooling solutions and formulate thermal management strategies, including static immersion, dynamic immersion, and immersion modes with coordinated temperature control of static and dynamic; S4: According to the immersion liquid cooling solution, an immersion cooling structure is built in the immersion tank; S5: According to the immersion liquid cooling solution, remove the threaded plug at the appropriate position of the box cover and replace it with an explosion-proof valve; S6: setting the boundary conditions of the test, including the environment, coolant flow rate and coolant inlet temperature parameters; S7: Turn on the test system and conduct a thermal safety performance test.

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