A lithium ion battery thermal runaway test device and test method

Abstract

This invention relates to the field of lithium-ion battery thermal runaway testing technology, specifically to a lithium-ion battery thermal runaway testing device and method. The testing device comprises an outer shell and an inner cylinder placed inside the outer shell, with the inner side of the inner cylinder forming the test area for the lithium-ion battery. A thermal insulation layer is arranged in the gap between the outer shell and the inner cylinder. A top cover is securely connected to the top wall of the inner cylinder to seal the inner cylinder and the gap. This invention, through its three-layer structure of the inner cylinder, thermal insulation layer, and outer shell, effectively ensures the thermal insulation performance of the test area. By adjusting the temperature control device, thermal runaway tests can be conducted at different test temperatures to obtain more comprehensive test data. Simultaneously, the gas collection port allows for the collection of gas within the test area at each stage of thermal runaway, achieving the goal of simultaneously acquiring temperature data and gas generation at each stage of thermal runaway, providing reliable data support for subsequent analysis.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion battery thermal runaway test, in particular to a lithium ion battery thermal runaway test device and test method. BACKGROUND

[0002] At present, there is no commercialized lithium ion battery thermal runaway test device that can be directly used on the market, and only a few tests are carried out in the laboratory under the condition of lithium ion battery thermal runaway under the condition of needle puncture. There is no corresponding test device for the thermal runaway of 18650 type general battery under the working condition caused by short circuit.

[0003] The general lithium ion battery thermal runaway test device is usually composed of a test cylinder, a sensor and a cover plate,

[0004] Generally, only the temperature or pressure change of a single lithium ion battery under thermal runaway state can be studied, but the thermal runaway state of lithium ion under different temperature environments may be different. If the internal temperature of the cylinder cannot be stably controlled, it is difficult to accurately obtain the thermal runaway test data of lithium ion battery under different temperature environments. And lithium ion battery thermal runaway has different stages (electrolyte decomposition stage, positive material decomposition stage, negative material decomposition stage, etc.), in order to obtain more comprehensive test data, the test temperature and the gas in the test area need to be collected at different stages of thermal runaway of lithium ion battery, in order to analyze the hazard of thermal runaway. If the test temperature is greatly affected by the outside world, the test temperature and gas production of lithium ion battery under different thermal runaway stages may be affected by the outside environment, so as to ensure the reliability of the test results. SUMMARY

[0005] The present application provides a lithium ion battery thermal runaway test device, which can preferably ensure the heat preservation performance of the test area through the three-layer structure of the inner cylinder, the heat preservation layer and the shell, so as to carry out thermal runaway test at different test temperatures by adjusting the temperature control device to obtain more comprehensive test data. And the more accurate surface temperature obtained by the thermocouple sensor during the test can determine the current thermal runaway stage of the lithium ion battery, and the gas in the test area can be collected at each thermal runaway stage through the gas collection port, so as to realize the purpose of synchronously obtaining the temperature data and gas production at each thermal runaway stage, and provide reliable data support for subsequent test analysis.

[0006] The present application solves the problem by adopting the following technical scheme:

[0007] In a first aspect, the present application provides a lithium ion battery thermal runaway test device, which comprises:

[0008] a shell,

[0009] an inner cylinder placed in the outer shell, a test area being formed in the inner cylinder; a heat preservation layer arranged in a gap between the outer shell and the inner cylinder;

[0010] a top cover used for covering the top of the inner cylinder to seal the test area and the gap;

[0011] a battery holder arranged in the test area, the battery holder being used for placing a lithium ion battery, and a heating mechanism used for heating the lithium ion battery being further arranged on the battery holder;

[0012] a thermocouple sensor arranged on the battery holder; the thermocouple sensor is used for being attached to the surface layer of the lithium ion battery to obtain the surface layer temperature of the lithium ion battery in real time during the heating of the heating mechanism;

[0013] a temperature sensor arranged at the bottom wall of the top cover, the temperature sensor being used for obtaining the real-time temperature of the test area;

[0014] a temperature control device arranged on the inner cylinder, the temperature control device being used for adjusting the temperature of the test area according to the real-time temperature;

[0015] a gas collection port arranged on the top cover, the gas collection port being used for being opened for a preset time when the surface layer temperature of the lithium ion battery reaches a plurality of preset temperatures, so as to collect the gas in the test area at each stage of thermal runaway of the lithium ion battery.

[0016] Optionally, a gasket is arranged at the top wall of the inner cylinder, and the top cover is fastened to the gasket by bolts.

[0017] Optionally, the inner cylinder and the top cover are made of stainless steel, and the gasket is made of silica gel.

[0018] Optionally, the heat preservation layer comprises heat preservation foam.

[0019] Optionally, the heating mechanism comprises a heating rod or a heating wire.

[0020] Optionally, a pressure sensor is further arranged at the bottom wall of the top cover, and the pressure sensor is used for obtaining the real-time pressure of the test area.

[0021] Optionally, the device further comprises:

[0022] an explosion-proof glass fixed on the side wall of the inner cylinder through the outer shell and the heat preservation layer, and the test area can be observed through the explosion-proof glass.

[0023] Optionally, the outer shell comprises a bottom plate and a plurality of outer shell plates vertically arranged on the bottom plate.

[0024] Optionally, the lithium ion battery is a 18650 type lithium ion battery.

[0025] In a second aspect, the present application provides a lithium ion battery thermal runaway test method, which utilizes the lithium ion battery thermal runaway test device to perform, and comprises the following steps:

[0026] Step S1: placing the lithium ion battery to be detected on the battery support in the test area;

[0027] Step S2: fastening the top cover to the inner cylinder top wall, and checking the air tightness of the test area;

[0028] Step S3: controlling the temperature control device to adjust the temperature of the test area until the real-time temperature measured by the temperature sensor reaches the preset test temperature;

[0029] Step S4: controlling the heating mechanism to heat the lithium ion battery;

[0030] Step S5: when the lithium ion battery is heated to a surface layer temperature reaching a preset value, opening the gas collection port to collect the gas in the test area at the current thermal runaway stage within a preset time;

[0031] Step S6: the temperature control device adjusts the temperature of the test area to another preset test temperature in turn, and repeats steps S4 and S5 to obtain test data at each preset test temperature.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] The three-layer structure of the shell, the inner cylinder and the heat preservation layer can better isolate the test area in the inner cylinder from the external environment, thereby improving the safety and heat preservation of the test area. Under the premise of ensuring the safety of the test, the test personnel can observe the thermal runaway process of the battery in situ during the thermal runaway process of the lithium ion battery. Under the premise of ensuring that the temperature of the test area is less affected by the external environment, the temperature sensor and the thermocouple sensor can more accurately obtain the real-time temperature of the test area at each stage of the battery thermal runaway, and the gas collection port can also collect the gas in the test area at each thermal runaway stage to analyze the gas production. In addition, the temperature control device can control the test temperature, so that the thermal runaway test of the lithium ion battery can be performed at different temperature environments to obtain more comprehensive test data. The entire test device structure of the present application is complete and reliable, and can realize the synchronous collection of temperature data, pressure data and gas production of the thermal runaway test, providing reliable data support for subsequent test analysis. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The structure of a lithium ion battery thermal runaway test device in Example 1 is shown in the figure;

[0035] Figure 2 Fig. 1 is a schematic view of the structure of the lithium ion battery according to the present application; Figure 1 Fig. 2 is a schematic view of the structure of the inner cylinder in the lithium ion battery according to the present application;

[0036] Figure 3 Fig. 3 is a schematic view of the structure of the top cover in the lithium ion battery according to the present application; Figure 1 Fig. 4 is a schematic view of the structure of the gasket in the lithium ion battery according to the present application;

[0037] Figure 4 Fig. 5 is a schematic view of the structure of the bottom plate in the lithium ion battery according to the present application; Figure 1 Fig. 6 is a schematic view of the structure of the shell plate in the lithium ion battery according to the present application;

[0038] Figure 5 Fig. 7 is a schematic view of the structure of the gasket in the lithium ion battery according to the present application; Figure 2 Fig. 8 is a schematic view of the structure of the bottom plate in the lithium ion battery according to the present application;

[0039] Figure 6 Fig. 9 is a schematic view of the structure of the shell plate in the lithium ion battery according to the present application; Figure 2 Fig. 10 is a schematic view of the structure of the shell plate in the lithium ion battery according to the present application;

[0040] Figure 7 Fig. 11 is a schematic view of the structure of the shell plate in the lithium ion battery according to the present application;

[0041] In the drawings, 1 is a gas collection port; 2 is a pressure sensor interface; 3 is a temperature sensor interface; 4 is a heating mechanism; 5 is a temperature control device; 6 is a top cover; 7 is a gasket; 8 is an inner cylinder; 9 is a shell; 10 is a thermal insulation layer; 11 is a bottom plate; 12 is a battery support; 13 is a lithium ion battery; 14 is an explosion-proof glass; 15 is a shell plate; 16 is an observation window. DETAILED DESCRIPTION

[0042] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more. In the description of the present application, it needs to be explained that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0043] The present application will be further described below in conjunction with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application. Example 1

[0044] In combination Figure 1 , the present embodiment provides a lithium ion battery thermal runaway test device, which comprises: a shell 9, an inner cylinder 8, a top cover 6 and a battery support 12; in combination Figure 2 , the inner cylinder 8 is placed in the shell 9, and the inner side of the inner cylinder 8 forms a test area of the lithium ion battery 13; in the present embodiment, the lithium ion battery 13 is a 18650 type lithium ion battery. The test device body of the present embodiment is a two-layer structure of the shell 9 and the inner cylinder 8, which can preferably improve the safety so that the test personnel can observe the test situation at a closer distance. The gap between the shell 9 and the inner cylinder 8 is arranged with a heat preservation layer 10; in the present embodiment, the temperature of the test area can be ensured as much as possible by the heat preservation layer 10 not to be affected by the outside world, so as to ensure that the subsequent test data related to temperature is better in accuracy. In a specific embodiment, the heat preservation layer 10 comprises heat preservation foam composed of rubber plastic cotton.

[0045] The top cover 6 can be fastened to the top wall of the inner cylinder 8 to close the inner cylinder 8 and the gap where the heat insulation layer 10 is arranged. Figures 3 to 5 In this embodiment, the gasket 7 can be arranged at the top wall of the inner cylinder 8, and the gasket 7 can be fastened to the top cover 6 as the outer eaves of the top wall of the inner cylinder 8. In a specific embodiment, the shell 9, the inner cylinder 8, and the top cover 6 are all made of 304 stainless steel to improve the safety of the entire test device, and the gasket 7 is made of silica gel, which can not only ensure the connection between the inner cylinder 8 and the top cover 6, but also ensure that the test area maintains good airtightness after the top cover 6 closes the inner cylinder 8.

[0046] In this embodiment, the battery holder 12 is arranged in the inner cylinder 8, and the battery holder 12 is used to place the lithium ion battery 13. The battery holder 12 is also provided with a heating mechanism 4 for heating the lithium ion battery 13 to be tested. The battery holder 12 is also provided with a thermocouple sensor, which is used to abut the surface layer of the lithium ion battery 13 to obtain the surface temperature of the battery in real time during the heating process of the heating mechanism 4. In a specific embodiment, the heating mechanism 4 includes a heating rod or a heating wire. If a heating rod is used as the heating mechanism 4, the heating rod can be abutted on the lithium ion battery 13. If a heating wire is used as the heating mechanism 4, the heating wire can be wound on the lithium ion battery 13, so that a better heating effect is obtained.

[0047] The bottom wall of the top cover 6 is also provided with a temperature sensor, which is used to obtain the real-time temperature of the test area. The inner cylinder 8 is also provided with a temperature control device 5, which is used to adjust the temperature of the test area according to the real-time temperature measured by the temperature sensor. The top cover 6 is also provided with a gas collection port 1, which is used to open for a preset time when the surface temperature of the lithium ion battery 13 reaches each preset temperature, so as to collect the gas in the test area at each thermal runaway stage and analyze the gas production. After the gas collection port is opened for a preset time, the collected gas is released into a container with a label for preservation and analysis to determine the gas production of the corresponding thermal runaway stage.

[0048] The heating process of the lithium ion battery 13 has at least the following stages: an initial heating stage (the internal resistance of the battery increases, the internal resistance generates heat, and the temperature rises), an electrolyte decomposition stage (the electrolyte begins to decompose, decomposition generates gas and heat, and the battery may swell or bulge), a positive electrode material decomposition stage (the positive electrode material decomposes, further releasing heat and gas), a negative electrode material decomposition stage (the negative electrode material reacts with the electrolyte, generating more heat and gas), and a thermal runaway stage (the entire battery system loses control, and intense heat release and gas release occur). The preset temperatures corresponding to different stages can be set or calibrated according to actual conditions, so that the corresponding test data and corresponding gas products of each stage of the lithium ion battery 13 thermal runaway can be accurately obtained.

[0049] In combination with a specific test method, a specific test method of the lithium ion battery 13 thermal runaway test device in this embodiment includes: step S1: placing the lithium ion battery 13 to be detected on the battery support 12 in the test area; step S2: tightly connecting the top cover 6 and the top wall of the inner cylinder 8; step S3: controlling the temperature control device 5 to adjust the temperature of the test area until the real-time temperature measured by the temperature sensor reaches the preset test temperature; step S4: controlling the heating mechanism 4 to heat the lithium ion battery 13; step S5: when the lithium ion battery 13 is heated to a surface layer temperature reaching a preset value, the gas collection port 1 is opened to collect the gas in the test area of the current thermal runaway stage; step S6: the temperature control device 5 adjusts the temperature of the test area to each preset test temperature in turn, and repeats steps S4 and S5 to record the test data at different test temperatures.

[0050] Through the above steps, the test area can be better isolated from the external environment by the double-layer structure of the outer shell 9 and the inner cylinder 8 cooperating with the heat preservation layer 10 between the two layers, which not only improves the heat insulation performance of the test area, but also ensures the safety of the test. Under the premise of good heat insulation performance of the test area, the test personnel can more accurately obtain the test data of each stage of the lithium ion battery 13 thermal runaway at different test temperatures through the temperature control device 5, the temperature sensor, and the thermocouple sensor. The test data obtained is accurate and comprehensive, thereby providing reliable data support for subsequent test analysis.

[0051] In a specific embodiment, to obtain more comprehensive test data, a pressure sensor is further arranged at the bottom wall of the top cover 6, and the pressure sensor is used to obtain the real-time pressure of the test area. Through the pressure sensor, the pressure data at each stage of the lithium ion battery 13 thermal runaway can be obtained to cooperate with the temperature data and the collected gas to analyze the lithium ion battery 13 thermal runaway in more detail. Through the above test method, the temperature, pressure, and gas production in each stage of the lithium battery thermal runaway process can be simultaneously collected under the premise of ensuring safety.

[0052] In this embodiment, the combination of Figure 2 and Figure 6 The shell 9 comprises a bottom plate 11 and a plurality of shell plates 15 erected on the bottom plate 11. The shell plates 15 are fixed on the bottom plate 11 by bolts, and are convenient to disassemble and assemble. The thermocouple sensor and the heating mechanism 4 in this embodiment are connected with the external communication terminal through the interfaces provided on the shell plates 15. A plurality of open grooves are provided on the shell plates 15, and corresponding positions on the inner cylinder 8 are also provided with openings. The thermocouple interface and the heating rod interface are respectively installed in each of the open grooves on the shell plates 15. In this embodiment, the heat preservation layer 10 is also provided with openings corresponding to the positions of the thermocouple interface and the heating rod interface to ensure that the interfaces can be connected with the thermocouple and the heating rod in the inner cylinder. Similarly, the temperature sensor interface 3 and the pressure sensor interface 2 are also provided on the top cover 6 to be connected with the external communication terminal. Embodiment 2

[0053] The difference between this embodiment and embodiment 1 is that, in this embodiment, under the premise of ensuring the safety of the test device, the combination of Figure 7 The test device further comprises an explosion-proof glass 14, which is fixed on the side wall of the inner cylinder 8 through the shell 9 and the heat preservation layer 10. The test area can be observed through the explosion-proof glass 14. At least one of the shell plates 15 is provided with an observation window 16, and the corresponding position of the inner cylinder 8 is also provided with an opening. The explosion-proof glass 14 is fixed on the inner cylinder 8 through the observation window 16, the heat preservation layer 10 and the opening on the inner cylinder 8, so that the test personnel can directly observe the thermal runaway process of the lithium ion battery.

[0054] This embodiment can synchronously collect the temperature, pressure and gas production in each stage of the thermal runaway process of the lithium battery under the premise of ensuring safety through the above test method, and can observe the test situation in real time through the explosion-proof glass 14.

[0055] The above is only the preferred embodiment of the present application. It should be noted that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A lithium-ion battery thermal runaway test device, characterized in that, The device comprises: a shell (9), an inner cylinder (8) placed in the shell (9), a test area being formed in the inner cylinder (8); a heat preservation layer (10) being arranged in the gap between the shell (9) and the inner cylinder (8); a top cover (6) used for covering the top of the inner cylinder (8) to seal the test area and the gap; a battery support (12) arranged in the test area, the battery support (12) being used for placing a lithium ion battery (13), and a heating mechanism (4) for heating the lithium ion battery (13) being further arranged on the battery support (12); a thermocouple sensor arranged on the battery support (12); the thermocouple sensor is used for being attached to the surface layer of the lithium ion battery (13) to obtain the surface layer temperature of the lithium ion battery (13) in real time during the heating of the lithium ion battery (13) by the heating mechanism (4); a temperature sensor arranged at the bottom wall of the top cover (6), the temperature sensor being used for obtaining the real-time temperature of the test area; a temperature control device (5) arranged on the inner cylinder (8), the temperature control device (5) being used for adjusting the temperature of the test area according to the real-time temperature; a gas collection port (1) opened on the top cover (6), the gas collection port (1) being used for being opened for a preset time when the surface layer temperature of the lithium ion battery (13) reaches a preset temperature, so as to collect the gas in the test area at each stage of thermal runaway of the lithium ion battery (13).

2. The lithium-ion battery thermal runaway test device of claim 1, wherein, A gasket (7) is arranged at the top wall of the inner cylinder (8), and the top cover (6) is fastened and connected with the gasket (7) through bolts.

3. The device of claim 2, wherein the device is configured to: The inner cylinder (8) and the top cover (6) are made of 304 stainless steel, and the gasket (7) is made of silica gel.

4. The lithium-ion battery thermal runaway test device of claim 1, wherein, The heat preservation layer (10) comprises heat preservation foam.

5. The lithium-ion battery thermal runaway test device of claim 1, wherein, The heating mechanism (4) comprises a heating rod or a heating wire.

6. The lithium-ion battery thermal runaway test device of claim 1, wherein, A pressure sensor is further arranged at the bottom wall of the top cover (6), and the pressure sensor is used for obtaining the real-time pressure of the test area.

7. The lithium-ion battery thermal runaway test device of claim 1, wherein, Further comprising: an explosion-proof glass (14) fixed on the side wall of the inner cylinder (8) through the shell (9) and the heat preservation layer (10), and the test area can be observed through the explosion-proof glass (14).

8. The lithium-ion battery thermal runaway test device of claim 1, wherein, The shell (9) comprises a bottom plate (11) and a plurality of shell plates (15) vertically arranged on the bottom plate (11).

9. The lithium-ion battery thermal runaway test device of claim 1, wherein, The lithium ion battery (13) is a 18650 type lithium ion battery.

10. A method of testing a lithium-ion battery for thermal runaway, the method comprising: providing a lithium-ion battery; providing a thermal runaway test device; and placing the lithium-ion battery in thermal communication with the thermal runaway test device. The lithium ion battery thermal runaway test device of any one of claims 1-9 is used to perform the following steps: Step S1: placing a lithium ion battery (13) to be detected on a battery support (12) in a test area; Step S2: covering a top cover (6) on the inner cylinder (8), and checking the air tightness of the test area to ensure that the air tightness is good; Step S3: controlling a temperature control device (5) to adjust the temperature of the test area until the real-time temperature measured by a temperature sensor reaches a preset test temperature; Step S4: controlling a heating mechanism (4) to heat the lithium ion battery (13); Step S5: opening a gas collection port (1) on the top cover (6) for a preset time when the surface layer temperature of the lithium ion battery (13) reaches a preset temperature, so as to collect the gas in the test area at each stage of thermal runaway of the lithium ion battery (13). Step S5: when the lithium ion battery (13) is heated to the surface temperature reaching each preset value, the gas collection port (1) is opened to collect the gas in the test area of each thermal runaway stage for a preset time; Step S6: the temperature control device (5) adjusts the temperature of the test area to another preset test temperature, and repeats steps S4 and S5.

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