Secondary battery overpressure shock wave testing device and testing method

Abstract

A secondary battery overpressure shock wave testing device and a testing method, the secondary battery overpressure shock wave testing device comprising a shell, a cover, a heating mechanism, a pressure sensor and a control mechanism. The shell is provided with a first sealed cavity and a first opening communicating with the first sealed cavity, and the first sealed cavity is configured to accommodate a secondary battery. The cover is configured to be covered on the first opening to seal the first sealed cavity. The heating mechanism is connected in the first sealed cavity, and the heating mechanism is configured to heat the first sealed cavity to make the secondary battery in the first sealed cavity explode to generate an overpressure shock wave. The pressure sensor is connected to the cover and is configured to sense the pressure value in the first sealed cavity. The control mechanism is electrically connected to the pressure sensor, and the control mechanism is configured to continuously acquire the pressure value sensed by the pressure sensor and calculate the pressure value of the overpressure shock wave. The above-mentioned secondary battery overpressure shock wave testing device and testing method can improve the accuracy of the test.

Description

Technical Field

[0001] This application relates to the field of secondary battery testing technology, and in particular to a secondary battery overpressure shock wave testing device and testing method. Background Technology

[0002] Secondary batteries are at risk of explosion when subjected to external environmental interference. Currently, there are no devices or methods to accurately test the overpressure shock wave of secondary batteries, and it is impossible to simulate and assess the destructive force of the overpressure shock wave of secondary batteries. Summary of the Invention

[0003] In view of the above situation, it is necessary to provide a secondary battery overpressure shock wave testing device that can improve the accuracy of the test.

[0004] This application provides an overpressure shock wave testing device for a secondary battery. The device includes a housing, a cover, a heating mechanism, a pressure sensor, and a control mechanism. The housing has a first sealed cavity and a first opening communicating with the first sealed cavity, which is configured to accommodate a secondary battery. The cover is configured to cover the first opening to seal the first sealed cavity. The heating mechanism is connected to the first sealed cavity and configured to heat the cavity, causing the secondary battery within to explode and generate an overpressure shock wave. The pressure sensor is connected to the cover and configured to sense the pressure value within the first sealed cavity. The control mechanism is electrically connected to the pressure sensor and configured to continuously acquire the pressure value sensed by the pressure sensor and calculate the pressure value of the overpressure shock wave. Before the secondary battery explodes, the pressure value closest to the time of the explosion is defined as a first pressure value; during and after the explosion, the maximum value among the pressure values ​​is defined as a second pressure value, and the difference between the second and first pressure values ​​is the pressure value of the overpressure shock wave.

[0005] In the aforementioned secondary battery overpressure shock wave testing device, a first sealed cavity is sealed by a housing and a cover. A heating mechanism heats the first sealed cavity, causing the secondary battery inside to explode and generate an overpressure shock wave. A pressure sensor senses the pressure value of the overpressure shock wave. A control mechanism continuously acquires the pressure values ​​sensed by the pressure sensor and calculates the pressure value of the overpressure shock wave. Specifically, before the secondary battery explodes, the pressure value closest to the time of the explosion is defined as the first pressure value; during and after the explosion, the maximum pressure value is defined as the second pressure value. The difference between the second and first pressure values ​​is the pressure value of the overpressure shock wave. Calculating the overpressure shock wave pressure value using this difference improves the accuracy of the test.

[0006] In some embodiments of this application, the heating mechanism is configured to heat the first sealed cavity to bring the temperature inside the first sealed cavity to a preset temperature, the preset temperature being in the range of 30°C to 300°C, so that the preset temperature can reach the temperature of thermal runaway of the secondary battery, and the energy consumption of the heating mechanism is limited.

[0007] In some embodiments of this application, the preset temperature range is 130°C to 230°C, so as to further facilitate the preset temperature to reach the temperature of thermal runaway of the secondary battery and limit the energy consumption of the heating mechanism.

[0008] In some embodiments of this application, the heating mechanism is further configured to maintain a preset temperature in the first sealed cavity for a preset duration, the preset duration being 0 to 30 hours, so that the internal and external temperatures of the secondary battery in the first sealed cavity are consistent and reach the preset temperature.

[0009] In some embodiments of this application, the preset duration ranges from 10 minutes to 60 minutes, in order to further facilitate the uniformity of the internal and external temperatures of the secondary battery in the first sealed cavity and to reach the preset temperature.

[0010] In some embodiments of this application, the heating rate in the first sealed cavity ranges from 1°C / min to 20°C / min. This setting can improve testing efficiency, reduce the risk of inconsistent temperatures inside and outside the secondary battery, and improve testing accuracy.

[0011] In some embodiments of this application, the heating rate within the first sealed cavity is 3°C / min to 7°C / min. This setting further improves testing efficiency, reduces the risk of inconsistent temperatures inside and outside the secondary battery, and enhances testing accuracy.

[0012] In some embodiments of this application, the secondary battery overpressure shock wave testing device further includes adhesive tape, which is configured to cover the conductive parts of the secondary battery to reduce the risk of short circuits between the conductive parts of the secondary battery and the structure within the first sealed cavity, thereby improving the accuracy of the test.

[0013] In some embodiments of this application, the cover has a second sealing cavity and a second opening communicating with the second sealing cavity. The second sealing cavity is configured to communicate with the first sealing cavity through the second opening when the cover is placed over the first opening. A pressure sensor is connected to the second sealing cavity. At least a portion of the heating mechanism is connected to the second sealing cavity. The ratio of the volume of the second sealing cavity to the volume of the first sealing cavity ranges from 5% to 50%, and the second and first sealing cavities are configured to accommodate the secondary battery in either the second or first sealing cavity, which is adapted to the volume of the secondary battery. The secondary battery overpressure shock wave testing device also includes a partition, which is configured to communicate between the first and second sealing cavities when the secondary battery is accommodated in the first sealing cavity, and to separate the first and second sealing cavities when the secondary battery is accommodated in the second sealing cavity. By adapting the second and first sealing cavities to secondary batteries of different volumes, the risk of insufficient pressure variation within the sealing cavity due to a large difference between the volume of the secondary battery and the volume of the sealing cavity affects the test accuracy. Simultaneously, by sharing a pressure sensor between the second and first sealing cavities, production costs can be reduced.

[0014] In some embodiments of this application, when the ratio of the volume of the secondary battery to the volume of the first sealed cavity is between 50% and 95%, the first sealed cavity is adapted to the volume of the secondary battery, and the secondary battery is contained in the first sealed cavity; when the ratio of the volume of the secondary battery to the volume of the second sealed cavity is between 50% and 95%, the second sealed cavity is adapted to the volume of the secondary battery, and the secondary battery is contained in the second sealed cavity.

[0015] In some embodiments of this application, the distance between the pressure sensor and the secondary battery in the first sealed cavity ranges from 5 cm to 10 cm, and the distance between the pressure sensor and the secondary battery in the second sealed cavity ranges from 1 mm to 5 mm. This arrangement reduces the risk of damage to the pressure sensor and improves the accuracy of the test.

[0016] Embodiments of this application also provide a method for testing overpressure shock waves of a secondary battery, the method comprising:

[0017] The secondary battery is placed in a sealed cavity;

[0018] Heating the sealed cavity causes the secondary battery inside to explode, generating an overpressure shock wave.

[0019] Sensing the pressure value inside the sealed cavity;

[0020] The pressure value of the overpressure shock wave is calculated by measuring the change in pressure within the sealed cavity.

[0021] In the above-mentioned overpressure shock wave test method for secondary batteries, the secondary battery inside the sealed cavity is exploded by heating the sealed cavity to generate an overpressure shock wave. The pressure value of the overpressure shock wave is calculated by the change in pressure value inside the sealed cavity, which helps to improve the accuracy of the test.

[0022] In some embodiments of this application, before the secondary battery explodes, the pressure value in the sealed cavity closest to the time of the secondary battery explosion is defined as the first pressure value. During and after the secondary battery explosion, the maximum value among the pressure values ​​in the sealed cavity is defined as the second pressure value. The difference between the second pressure value and the first pressure value is the pressure value of the overpressure shock wave. Calculating the pressure value of the overpressure shock wave through the difference is beneficial to improving the accuracy of the test.

[0023] In some embodiments of this application, the overpressure shock wave test method for secondary batteries further includes: adjusting the volume of the sealed cavity to match the volume of the secondary battery, thereby reducing the risk that a large difference between the volume of the secondary battery and the volume of the sealed cavity would result in a small change in the pressure value inside the sealed cavity, affecting the test accuracy. Specifically, when the ratio of the volume of the secondary battery to the volume of the sealed cavity is between 50% and 95%, the volume of the sealed cavity is considered to match the volume of the secondary battery.

[0024] In some embodiments of this application, the overpressure shock wave test method for secondary batteries further includes: wrapping the conductive parts of the secondary battery with adhesive tape to reduce the risk of short circuits in the conductive parts and the structure inside the sealed cavity of the secondary battery, thereby improving the accuracy of the test.

[0025] In some embodiments of this application, the heating of the sealing cavity brings the temperature inside the sealing cavity to a preset temperature, which ranges from 30°C to 300°C. This facilitates reaching the temperature at which the secondary battery thermally runs away and limits energy consumption.

[0026] In some embodiments of this application, the sealed cavity is controlled to maintain a preset temperature for a preset duration, which is 0 to 30 hours, so that the internal and external temperatures of the secondary battery in the sealed cavity are consistent and reach the preset temperature.

[0027] In some embodiments of this application, the heating rate within the sealed cavity is controlled to range from 1°C / min to 20°C / min. This setting improves testing efficiency, reduces the risk of inconsistent temperatures inside and outside the secondary battery, and enhances testing accuracy. Attached Figure Description

[0028] Figure 1 This is a first structural schematic diagram of a secondary battery overpressure shock wave testing device in one embodiment of this application.

[0029] Figure 2 This is a schematic diagram of the control mechanism of a secondary battery overpressure shock wave testing device in one embodiment of this application.

[0030] Figure 3 This is a schematic diagram of the second structure of a secondary battery overpressure shock wave testing device in one embodiment of this application.

[0031] Figure 4 This is a flowchart illustrating a secondary battery overpressure shock wave testing method in one embodiment of this application.

[0032] Explanation of main component symbols

[0033] Secondary battery overpressure shock wave testing device 100

[0034] Casing 10

[0035] First sealing cavity 11

[0036] First opening 12

[0037] Cover 20

[0038] Second sealing cavity 21

[0039] Second opening 22

[0040] Heating mechanism 30

[0041] Pressure sensor 40

[0042] Control mechanism 50

[0043] Get Module 51

[0044] First Calculation Module 52

[0045] Judgment Module 53

[0046] Second calculation module 54

[0047] Recording Module 55

[0048] partition 60

[0049] Secondary battery 90

[0050] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0052] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have a component that is centrally located. When a component is considered to be "set" on another component, it can be directly set on the other component or may also have a component that is centrally located.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0054] This application provides an overpressure shock wave testing device for a secondary battery. The device includes a housing, a cover, a heating mechanism, a pressure sensor, and a control mechanism. The housing has a first sealed cavity and a first opening communicating with the first sealed cavity, which is configured to accommodate a secondary battery. The cover is configured to cover the first opening to seal the first sealed cavity. The heating mechanism is connected to the first sealed cavity and configured to heat the cavity, causing the secondary battery within to explode and generate an overpressure shock wave. The pressure sensor is connected to the cover and configured to sense the pressure value within the first sealed cavity. The control mechanism is electrically connected to the pressure sensor and configured to continuously acquire the pressure value sensed by the pressure sensor and calculate the pressure value of the overpressure shock wave. Before the secondary battery explodes, the pressure value closest to the time of the explosion is defined as a first pressure value; during and after the explosion, the maximum value among the pressure values ​​is defined as a second pressure value, and the difference between the second and first pressure values ​​is the pressure value of the overpressure shock wave.

[0055] In the aforementioned secondary battery overpressure shock wave testing device, a first sealed cavity is sealed by a housing and a cover. A heating mechanism heats the first sealed cavity, causing the secondary battery inside to explode and generate an overpressure shock wave. A pressure sensor senses the pressure value of the overpressure shock wave. A control mechanism continuously acquires the pressure values ​​sensed by the pressure sensor and calculates the pressure value of the overpressure shock wave. Specifically, before the secondary battery explodes, the pressure value closest to the time of the explosion is defined as the first pressure value; during and after the explosion, the maximum pressure value is defined as the second pressure value. The difference between the second and first pressure values ​​is the pressure value of the overpressure shock wave. Calculating the overpressure shock wave pressure value using this difference improves the accuracy of the test.

[0056] The embodiments of this application also provide a method for testing overpressure shock waves of a secondary battery. The method includes: placing the secondary battery in a sealed cavity; heating the sealed cavity to cause the secondary battery inside the sealed cavity to explode and generate an overpressure shock wave; sensing the pressure value inside the sealed cavity; and calculating the pressure value of the overpressure shock wave by measuring the change in the pressure value inside the sealed cavity.

[0057] In the above-mentioned overpressure shock wave test method for secondary batteries, the secondary battery inside the sealed cavity is exploded by heating the sealed cavity to generate an overpressure shock wave. The pressure value of the overpressure shock wave is calculated by the change in pressure value inside the sealed cavity, which helps to improve the accuracy of the test.

[0058] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0059] Please see Figure 1 One embodiment of this application provides a secondary battery overpressure shock wave testing device 100 for testing the pressure of an overpressure shock wave from a secondary battery 90. Optionally, the secondary battery 90 is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, and lithium-ion polymer secondary batteries.

[0060] The secondary battery overpressure shock wave testing device 100 includes a housing 10, a cover 20, a heating mechanism 30, a pressure sensor 40, and a control mechanism 50. The housing 10 has a first sealed cavity 11 and a first opening 12 communicating with the first sealed cavity 11. The first sealed cavity 11 is configured to accommodate a secondary battery 90. The cover 20 is configured to cover the first opening 12 to seal the first sealed cavity 11, thereby placing the secondary battery 90 in a closed space to reduce interference from the external environment.

[0061] A heating mechanism 30 is connected to the first sealed cavity 11. The heating mechanism 30 is configured to heat the first sealed cavity 11, causing the secondary battery 90 inside the first sealed cavity 11 to explode and generate an overpressure shock wave. Specifically, the temperature of the first sealed cavity 11 gradually increases under the continuous heating of the heating mechanism 30, thereby gradually increasing the temperature of the secondary battery 90 located inside the first sealed cavity 11. Under high temperature conditions, a large number of exothermic side reactions occur inside the secondary battery 90, causing the internal temperature of the secondary battery 90 to rise uncontrollably and rapidly, leading to thermal runaway. Thermal runaway causes the internal pressure of the secondary battery 90 to increase rapidly, resulting in an explosion. The explosion causes the air inside the first sealed cavity 11 to expand rapidly in a short time, resulting in a rapid increase in air pressure and generating an overpressure shock wave. Optionally, the heating mechanism 30 is a heating rod.

[0062] Pressure sensor 40 is connected to cover 20 and located on the side of cover 20 facing the first sealing cavity 11. Pressure sensor 40 is configured to sense the pressure value of the first sealing cavity 11.

[0063] The control mechanism 50 is electrically connected to the pressure sensor 40. The control mechanism 50 is configured to continuously acquire the pressure value sensed by the pressure sensor 40 and calculate the pressure value of the overpressure shock wave. Specifically, before the secondary battery 90 explodes, the pressure value closest to the time of the secondary battery 90 explosion is defined as the first pressure value; during and after the secondary battery 90 explosion, the maximum value among the pressure values ​​is defined as the second pressure value, and the difference between the second pressure value and the first pressure value is the pressure value of the overpressure shock wave.

[0064] In the aforementioned secondary battery overpressure shock wave testing device 100, the first sealing cavity 11 is sealed by the cooperation of the housing 10 and the cover 20. The heating mechanism 30 heats the first sealing cavity 11, causing the secondary battery 90 inside to explode and generate an overpressure shock wave. A pressure sensor 40 senses the pressure value of the overpressure shock wave from the secondary battery 90. A control mechanism 50 continuously acquires the pressure values ​​sensed by the pressure sensor 40 and calculates the pressure value of the overpressure shock wave. Specifically, before the secondary battery 90 explodes, the pressure value closest to the time of the explosion is defined as the first pressure value; during and after the explosion, the maximum value among the pressure values ​​is defined as the second pressure value. The difference between the second and first pressure values ​​is the pressure value of the overpressure shock wave. Calculating the pressure value of the overpressure shock wave using this difference improves the accuracy of the test.

[0065] In some embodiments, the cover 20 is fixedly connected to the housing 10 by bolts (not shown). Specifically, multiple bolts are spaced apart along the edge of the cover 20 to ensure that the cover 20 is subjected to uniform force on its periphery and to improve the connection stability between the cover 20 and the housing 10.

[0066] In some embodiments, a sealing ring (not shown) is also provided between the cover 20 and the housing 10 to improve the sealing stability of the first sealing cavity 11.

[0067] In some embodiments, the first sealed cavity 11 and the battery compartment for assembling the secondary battery 90 are configured in a contoured manner to mimic the diffusion direction of the overpressure shock wave of the secondary battery 90 in the battery compartment, thereby enabling the test results to be closer to the real situation.

[0068] In some embodiments, the heating mechanism 30 is configured to heat the first sealed cavity 11 to a preset temperature, the preset temperature being in the range of 30°C to 300°C. If the preset temperature is too low (e.g., below 30°C), it will be below the thermal runaway temperature of the secondary battery 90, making it difficult for the secondary battery 90 to explode. If the preset temperature is too high (e.g., above 300°C), it will increase the energy consumption of the heating mechanism 30 even after the thermal runaway temperature of the secondary battery 90 has been reached. By setting the preset temperature to a range of 30°C to 300°C, it is easier for the preset temperature to reach the thermal runaway temperature of the secondary battery 90, while limiting the energy consumption of the heating mechanism 30.

[0069] Optionally, the preset temperature can be one of the following: 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, or any other value within the range of 30℃ to 300℃.

[0070] Furthermore, the preset temperature range is 130°C to 230°C, so as to facilitate the preset temperature reaching the thermal runaway temperature of the secondary battery 90 and limit the energy consumption of the heating mechanism 30.

[0071] In some embodiments, the heating mechanism 30 is further configured to maintain a preset temperature in the first sealed cavity 11 for a preset duration, the preset duration being 0 to 30 hours, so that the internal and external temperatures of the secondary battery 90 in the first sealed cavity 11 are consistent and reach the preset temperature.

[0072] Optionally, the preset duration can be one of the following: 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h, 30h, or any other value within the range of 0 to 30h.

[0073] Furthermore, the preset duration ranges from 10 minutes to 60 minutes, so as to further facilitate the uniformity of the internal and external temperatures of the secondary battery 90 in the first sealed cavity 11 and to reach the preset temperature.

[0074] In some embodiments, the heating rate within the first sealed cavity 11 ranges from 1°C / min to 20°C / min. A heating rate that is too slow (e.g., less than 1°C / min) results in a longer testing time, affecting testing efficiency. A heating rate that is too fast (e.g., greater than 20°C / min) leads to inconsistent temperatures inside and outside the secondary battery 90, affecting testing accuracy. By using a heating rate range of 1°C / min to 20°C / min, testing efficiency can be improved, the risk of inconsistent temperatures inside and outside the secondary battery 90 can be reduced, and testing accuracy can be improved.

[0075] Optionally, the heating rate within the first sealed cavity 11 can be any one of the following values: 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, 11℃ / min, 12℃ / min, 13℃ / min, 14℃ / min, 15℃ / min, 16℃ / min, 17℃ / min, 18℃ / min, 19℃ / min, 20℃ / min, or any other value within the range of 1℃ / min to 20℃ / min.

[0076] Furthermore, the heating rate within the first sealed cavity 11 is 3°C / min to 7°C / min to further improve testing efficiency and reduce the risk of inconsistent temperatures inside and outside the secondary battery 90, thereby improving testing accuracy.

[0077] In some embodiments, the control mechanism 50 is further configured to generate a graph showing the change of pressure value in the first sealed cavity 11 with test duration as the X-axis variable and pressure value as the Y-axis variable.

[0078] In some embodiments, the control mechanism 50 is further configured to determine the destructive force of the overpressure shock wave of the secondary battery based on the pressure value of the overpressure shock wave. Specifically, the control mechanism 50 acquires comparative data on the symptoms of injury caused by the pressure of the overpressure shock wave to the human body (see Table 1), determines the range of the pressure value of the overpressure shock wave, and indicates the corresponding symptoms of injury to the human body.

[0079] Table 1. Comparison of the harmful effects of shock wave pressure on the human body

[0080]

[0081] In some embodiments, the control mechanism 50 is further configured to calculate the explosion energy of the secondary battery 90. Specifically, the calculation formula is as follows:

[0082]

[0083] Where Eg is the explosion energy of the gas, in kJ; P is the pressure of the overpressure shock wave, in MPa; and V is the volume of the first sealed cavity 11, in m³. 3 ; k is the adiabatic index value of the gas.

[0084] Please refer to the following: Figure 2 Specifically, the control mechanism 50 includes an acquisition module 51, a first calculation module 52, a judgment module 53, a second calculation module 54, and a recording module 55. The control mechanism 50 performs the following steps:

[0085] The acquisition module 51 is configured to continuously acquire the pressure value sensed by the pressure sensor 40;

[0086] The first calculation module 52 is configured to calculate the pressure value of the overpressure shock wave. Before the secondary battery 90 explodes, the pressure value closest to the pressure value obtained when the secondary battery 90 explodes is defined as the first pressure value. When and after the secondary battery 90 explodes, the maximum value of the pressure values ​​is defined as the second pressure value. The difference between the second pressure value and the first pressure value is the pressure value of the overpressure shock wave.

[0087] The judgment module 53 is configured to judge the destructive force of the overpressure shock wave of the secondary battery based on the pressure value of the overpressure shock wave.

[0088] The second calculation module 54 is configured to calculate the explosion energy of the secondary battery 90.

[0089] The recording module 55 is configured to continuously record the pressure value and generate a graph showing the change of the pressure value over the test duration.

[0090] In some embodiments, the secondary battery overpressure shock wave testing device 100 further includes adhesive tape (not shown), which is configured to cover the conductive parts of the secondary battery 90 to reduce the risk of short circuits between the conductive parts of the secondary battery 90 and the structure within the first sealed cavity 11, thereby improving the accuracy of the test. Optionally, the conductive parts of the secondary battery 90 may include tabs, terminals, or circuit board assemblies, etc.

[0091] Please see Figure 3 In some embodiments, the cover 20 has a second sealing cavity 21 and a second opening 22 communicating with the second sealing cavity 21. The second sealing cavity 21 is configured to communicate with the first sealing cavity 11 through the second opening 22 when the cover 20 is placed over the first opening 12. A pressure sensor 40 is connected to the second sealing cavity 21. At least a portion of the heating mechanism 30 is connected to the second sealing cavity 21.

[0092] The ratio of the volume of the second sealing cavity 21 to the volume of the first sealing cavity 11 is in the range of 5% to 50%. The second sealing cavity 21 and the first sealing cavity 11 are configured to accommodate the secondary battery 90 in the second sealing cavity 21 or the first sealing cavity 11 adapted to the volume of the secondary battery 90.

[0093] The secondary battery overpressure shock wave testing device 100 also includes a partition 60. The partition 60 is configured to connect the first sealed cavity 11 and the second sealed cavity 21 when the second sealed cavity 11 contains the secondary battery 90. In this case, the pressure sensor 40 in the second sealed cavity 21 senses the pressure value in the first sealed cavity 11. The partition 60 is also configured to separate the first sealed cavity 11 and the second sealed cavity 21 when the second sealed cavity 21 contains the secondary battery 90. In this case, the pressure sensor 40 senses the pressure value in the second sealed cavity 21. By adapting the second sealed cavity 21 and the first sealed cavity 11 to accommodate secondary batteries 90 of different volumes, the risk of small pressure changes within the sealed cavity due to a large difference between the volume of the secondary battery 90 and the volume of the sealed cavity, which affects the test accuracy, is reduced. At the same time, by sharing the pressure sensor 40 between the second sealed cavity 21 and the first sealed cavity 11, production costs can be reduced.

[0094] It is understood that when the partition 60 separates the first sealing cavity 11 and the second sealing cavity 21, the heating mechanism 30 in the second sealing cavity 21 is configured to heat the second sealing cavity 21 to a preset temperature and to maintain the preset temperature in the second sealing cavity 21 for a preset duration. The preset temperature and preset duration of heating the second sealing cavity 21 by the heating mechanism 30 are the same as those of heating the first sealing cavity 11 by the heating mechanism 30. The calculation method for the pressure value of the overpressure shock wave of the secondary battery 90 in the second sealing cavity 21 is the same as that for the overpressure shock wave of the secondary battery 90 in the first sealing cavity 11. The calculation method for the explosion energy of the secondary battery 90 in the second sealing cavity 21 is the same as that for the explosion energy of the secondary battery 90 in the first sealing cavity 11, except that V is modified to be the volume value of the second sealing cavity 21.

[0095] Optionally, the ratio of the volume of the second sealing cavity 21 to the volume of the first sealing cavity 11 can be one of 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any other value within the range of 5% to 50%.

[0096] In some embodiments, when the ratio of the volume of the secondary battery 90 to the volume of the first sealed cavity 11 is between 50% and 95%, the first sealed cavity 11 is adapted to the volume of the secondary battery 90, and the secondary battery 90 is accommodated in the first sealed cavity 11.

[0097] Optionally, the ratio of the volume of the secondary battery 90 to the volume of the first sealed cavity 11 can be one of 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any other value within the range of 50% to 95%.

[0098] When the ratio of the volume of the secondary battery 90 to the volume of the second sealed cavity 21 is between 50% and 95%, the volume of the second sealed cavity 21 is adapted to the volume of the secondary battery 90, and the secondary battery 90 is accommodated in the second sealed cavity 21.

[0099] Optionally, the ratio of the volume of the secondary battery 90 to the volume of the second sealed cavity 21 can be one of 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any other value within the range of 50% to 95%.

[0100] In some embodiments, the partition 60 is fixedly connected to the cover 20 by bolts (not shown). Specifically, multiple bolts are spaced apart along the edge of the partition 60 to ensure that the force on the periphery of the partition 60 is uniform and to improve the connection stability between the partition 60 and the cover 20.

[0101] In some embodiments, a sealing ring (not shown) is also provided between the partition 60 and the cover 20 to improve the sealing stability of the first sealing cavity 11.

[0102] In some embodiments, the second sealed cavity 21 and the battery compartment for assembling the secondary battery 90 are configured in a contoured manner to mimic the diffusion direction of the overpressure shock wave of the secondary battery 90 in the battery compartment, thereby enabling the test results to be closer to the real situation.

[0103] In some embodiments, the distance between the pressure sensor 40 and the secondary battery 90 in the first sealed cavity 11 ranges from 5 cm to 10 cm. When the distance between the pressure sensor 40 and the secondary battery 90 in the first sealed cavity 11 is too short (e.g., less than 5 cm), the risk of the high temperature caused by the secondary battery 90 exploding and affecting the pressure sensor 40 increases. When the distance between the pressure sensor 40 and the secondary battery 90 in the first sealed cavity 11 is too long (e.g., greater than 10 cm), the time it takes for the overpressure shock wave to travel from the secondary battery 90 to the pressure sensor 40 increases, causing a delay in the pressure sensor 40's sensing and affecting the accuracy of the test. By keeping the distance between the pressure sensor 40 and the secondary battery 90 in the first sealed cavity 11 from 5 cm to 10 cm, the risk of damage to the pressure sensor 40 can be reduced, and the accuracy of the test can be improved.

[0104] Optionally, the distance between the pressure sensor 40 and the secondary battery 90 in the first sealed cavity 11 is one of 5cm, 6cm, 7cm, 8cm, 9cm, 10cm, or any other value within the range of 5cm to 10cm.

[0105] The distance between the pressure sensor 40 and the secondary battery 90 in the second sealed cavity 21 ranges from 1 mm to 5 mm. It is understood that, due to size and weight limitations, the explosion energy of the secondary battery 90 housed in the second sealed cavity 21 is typically less than that of the secondary battery 90 housed in the first sealed cavity 11. When the distance between the pressure sensor 40 and the secondary battery 90 in the second sealed cavity 21 is too short (e.g., less than 1 mm), the risk of the high temperature caused by the explosion of the secondary battery 90 affecting the pressure sensor 40 increases. When the distance between the pressure sensor 40 and the secondary battery 90 in the second sealed cavity 21 is too long (e.g., greater than 5 mm), the time it takes for the overpressure shock wave to travel from the secondary battery 90 to the pressure sensor 40 increases, causing a delay in the pressure sensor 40's sensing and affecting the accuracy of the test. By maintaining a distance between the pressure sensor 40 and the secondary battery 90 in the second sealed cavity 21 ranging from 1 mm to 5 mm, the risk of damage to the pressure sensor 40 can be reduced, and the accuracy of the test can be improved.

[0106] Optionally, the distance between the pressure sensor 40 and the secondary battery 90 in the second sealed cavity 21 is one of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or any other value within the range of 1 mm to 5 mm.

[0107] Please see Figure 4 An embodiment of this application also provides a method for testing overpressure shock waves of a secondary battery. The method for testing overpressure shock waves of a secondary battery includes:

[0108] The secondary battery 90 is placed in a sealed cavity;

[0109] Heating the sealed cavity causes the secondary battery 90 inside the sealed cavity to explode, generating an overpressure shock wave.

[0110] Sensing the pressure value inside the sealed cavity;

[0111] The pressure value of the overpressure shock wave is calculated by measuring the change in pressure within the sealed cavity.

[0112] Specifically, the pressure value inside the sealed cavity before the secondary battery 90 explodes is defined as the first pressure value, and the pressure value inside the sealed cavity during and after the secondary battery 90 explodes is defined as the second pressure value. The difference between the maximum value of the second pressure value and the first pressure value is the pressure value of the overpressure shock wave. Calculating the pressure value of the overpressure shock wave by using the difference is beneficial to improving the accuracy of the test.

[0113] In some embodiments, the overpressure shock wave test method for secondary batteries further includes: adjusting the volume of the sealed cavity to match the volume of the secondary battery 90, thereby reducing the risk that a large difference between the volume of the secondary battery 90 and the volume of the sealed cavity would result in a small change in the pressure value inside the sealed cavity, affecting the test accuracy. Specifically, when the ratio of the volume of the secondary battery 90 to the volume of the sealed cavity is between 50% and 95%, the volume of the sealed cavity is considered to match the volume of the secondary battery.

[0114] Optionally, the ratio of the volume of the secondary battery 90 to the volume of the sealed cavity can be one of 50%, 55%, 60%, 65%, 70%, 75%, 80%, 75%, 90%, 95%, or any other value within the range of 50% to 95%.

[0115] In some embodiments, the overpressure shock wave test method for secondary batteries further includes: wrapping the conductive parts of the secondary battery 90 with adhesive tape to reduce the risk of short circuits between the conductive parts of the secondary battery 90 and the structure within the sealed cavity, thereby improving the accuracy of the test. Optionally, the conductive parts of the secondary battery 90 include tabs, terminals, or circuit board assemblies, etc.

[0116] In some embodiments, the secondary battery overpressure shock wave test method further includes: determining the destructive force of the secondary battery overpressure shock wave based on its pressure value. Specifically, by using comparative data on the symptoms of human injury caused by the pressure of the overpressure shock wave (see Table 1), the range of the pressure value of the overpressure shock wave is determined and the corresponding symptoms of human injury are indicated.

[0117] In some embodiments, the overpressure shock wave test method for a secondary battery further includes: calculating the explosion energy of the secondary battery 90. Specifically, the calculation formula can refer to the calculation formula used by the control mechanism 50 to calculate the explosion energy of the secondary battery 90.

[0118] In some embodiments, the heated sealing cavity is heated to a preset temperature, which ranges from 30°C to 300°C. If the preset temperature is too low (e.g., below 30°C), it will be below the thermal runaway temperature of the secondary battery 90, making it difficult for the secondary battery 90 to explode. If the preset temperature is too high (e.g., above 300°C), it will increase energy consumption even after the thermal runaway temperature of the secondary battery 90 has already been reached. By limiting the preset temperature to 30°C to 300°C, it is easier to reach the thermal runaway temperature of the secondary battery 90 while limiting energy consumption.

[0119] Furthermore, the preset temperature range is 130°C to 230°C, so as to facilitate the preset temperature reaching the 90°C thermal runaway temperature of the secondary battery and limit energy consumption.

[0120] In some embodiments, the temperature inside the sealed cavity is controlled to be maintained at a preset temperature for a preset duration, which is 0 to 30 hours, so that the internal and external temperatures of the secondary battery 90 inside the sealed cavity are consistent and reach the preset temperature.

[0121] Furthermore, the preset duration ranges from 10 minutes to 60 minutes, in order to further ensure that the internal and external temperatures of the secondary battery 90 inside the sealed cavity are consistent and reach the preset temperature.

[0122] In some embodiments, the heating rate within the sealed cavity is controlled to range from 1°C / min to 20°C / min. A heating rate that is too slow (e.g., less than 1°C / min) results in a longer testing time, affecting testing efficiency. A heating rate that is too fast (e.g., greater than 20°C / min) leads to inconsistent temperatures inside and outside the secondary battery 90, affecting testing accuracy. By controlling the heating rate to range from 1°C / min to 20°C / min, testing efficiency can be improved, the risk of inconsistent temperatures inside and outside the secondary battery 90 can be reduced, and testing accuracy can be improved.

[0123] Furthermore, the heating rate inside the sealed cavity is 3℃ / min to 7℃ / min to further improve testing efficiency and reduce the risk of inconsistent temperatures inside and outside the secondary battery, thereby improving testing accuracy.

[0124] In the above-mentioned overpressure shock wave test method for secondary batteries, the secondary battery 90 inside the sealed cavity is exploded by heating the sealed cavity to generate an overpressure shock wave. The pressure value of the overpressure shock wave is calculated by the change in pressure value inside the sealed cavity, which helps to improve the accuracy of the test.

[0125] In addition, those skilled in the art may make other changes within the spirit of this application. Of course, all such changes made in accordance with the spirit of this application should be included within the scope disclosed in this application.

Claims

1. A secondary battery overpressure shock wave testing device, characterized in that, The secondary battery overpressure shock wave testing device includes: The housing has a first sealed cavity and a first opening communicating with the first sealed cavity, the first sealed cavity being configured to accommodate a secondary battery; A cover is configured to cover the first opening to seal the first sealing cavity; A heating mechanism is connected to the first sealed cavity, and the heating mechanism is configured to heat the first sealed cavity to cause the secondary battery inside the first sealed cavity to explode and generate an overpressure shock wave. A pressure sensor is connected to the cover and configured to sense the pressure value within the first sealed cavity; A control mechanism, electrically connected to the pressure sensor, is configured to continuously acquire the pressure value sensed by the pressure sensor and calculate the pressure value of the overpressure shock wave. Specifically, before the secondary battery explodes, a first pressure value is defined as the pressure value closest to the time of the secondary battery explosion; during and after the secondary battery explosion, the maximum value among the pressure values ​​is defined as a second pressure value, and the difference between the second pressure value and the first pressure value is the pressure value of the overpressure shock wave. The cover has a second sealing cavity and a second opening communicating with the second sealing cavity. The second sealing cavity is configured to communicate with the first sealing cavity through the second opening when the cover is placed over the first opening. The pressure sensor is connected to the second sealing cavity. At least a portion of the heating mechanism is connected to the second sealing cavity. The ratio of the volume of the second sealing cavity to the volume of the first sealing cavity is in the range of 5% to 50%. The second sealing cavity and the first sealing cavity are configured to accommodate the secondary battery in the second sealing cavity or the first sealing cavity that is adapted to the volume of the secondary battery, according to the volume of the secondary battery. The secondary battery overpressure shock wave testing device further includes a partition, which is configured to connect the first sealed cavity and the second sealed cavity when the second sealed cavity contains the secondary battery, and to separate the first sealed cavity and the second sealed cavity when the second sealed cavity contains the secondary battery.

2. The secondary battery overpressure shock wave testing device as described in claim 1, characterized in that, The heating mechanism is configured to heat the first sealing cavity to bring the temperature inside the first sealing cavity to a preset temperature, the preset temperature being in the range of 30°C to 300°C.

3. The secondary battery overpressure shock wave testing device as described in claim 2, characterized in that, The preset temperature range is 130°C to 230°C.

4. The secondary battery overpressure shock wave testing device as described in claim 2 or 3, characterized in that, The heating mechanism is also configured to maintain the preset temperature in the first sealed cavity for a preset duration, the preset duration being in the range of 0 to 30 hours.

5. The secondary battery overpressure shock wave testing device as described in claim 4, characterized in that, The preset duration ranges from 10 minutes to 60 minutes.

6. The secondary battery overpressure shock wave testing device as described in claim 3, characterized in that, The heating rate within the first sealed cavity ranges from 1°C / min to 20°C / min.

7. The secondary battery overpressure shock wave testing device as described in claim 6, characterized in that, The heating rate within the first sealed cavity is 3°C / min to 7°C / min.

8. The secondary battery overpressure shock wave testing device as described in claim 1, characterized in that, The secondary battery overpressure shock wave testing device also includes adhesive tape, which is configured to cover the conductive parts of the secondary battery.

9. The secondary battery overpressure shock wave testing device as described in claim 1, characterized in that, When the ratio of the volume of the secondary battery to the volume of the first sealed cavity is between 50% and 95%, the first sealed cavity is adapted to the volume of the secondary battery, and the secondary battery is accommodated in the first sealed cavity. When the ratio of the volume of the secondary battery to the volume of the second sealed cavity is between 50% and 95%, the second sealed cavity is adapted to the volume of the secondary battery, and the secondary battery is contained within the second sealed cavity.

10. The overpressure shock wave testing device for secondary batteries as described in claim 1, characterized in that, The distance between the pressure sensor and the secondary battery in the first sealed cavity ranges from 5cm to 10cm; the distance between the pressure sensor and the secondary battery in the second sealed cavity ranges from 1mm to 5mm.

11. A method for testing overpressure shock waves in a secondary battery, characterized in that, The secondary battery overpressure shock wave testing method uses the testing apparatus described in any one of claims 1 to 10, and the secondary battery overpressure shock wave testing method includes: The secondary battery is placed in a sealed cavity; Heating the sealed cavity causes the secondary battery inside to explode, generating an overpressure shock wave. The pressure value inside the sealed cavity is sensed; The pressure value of the overpressure shock wave is calculated by measuring the change in pressure within the sealed cavity.

12. The overpressure shock wave test method for secondary batteries as described in claim 11, characterized in that, Before the secondary battery explodes, the pressure value inside the sealed cavity closest to the time of the secondary battery explosion is defined as the first pressure value. During and after the secondary battery explosion, the maximum value of the pressure values ​​inside the sealed cavity is defined as the second pressure value. The difference between the second pressure value and the first pressure value is the pressure value of the overpressure shock wave.

13. The overpressure shock wave test method for secondary batteries as described in claim 11, characterized in that, The overpressure shock wave test method for secondary batteries further includes: adjusting the volume of the sealed cavity to match the volume of the secondary battery, wherein the volume of the sealed cavity matches the volume of the secondary battery when the ratio of the volume of the secondary battery to the volume of the sealed cavity is in the range of 50% to 95%.

14. The overpressure shock wave test method for secondary batteries as described in claim 11, characterized in that, The overpressure shock wave test method for secondary batteries further includes: wrapping the conductive parts of the secondary battery with adhesive tape.

15. The overpressure shock wave test method for secondary batteries as described in claim 11, characterized in that, The sealing cavity is heated to bring the temperature inside the sealing cavity to a preset temperature, which is in the range of 30°C to 300°C.

16. The overpressure shock wave test method for secondary batteries as described in claim 15, characterized in that, The temperature inside the sealed cavity is controlled to be maintained at a preset temperature for a preset duration, which is 0 to 30 hours.

17. The overpressure shock wave test method for secondary batteries as described in claim 11, characterized in that, The temperature rise rate within the sealed cavity is controlled within the range of 1°C / min to 20°C / min.

Images