Device and method for measuring gas flow rate and gas production amount of battery thermal runaway

Abstract

The present invention relates to a device for measuring the gas flow rate and gas production amount of a battery under thermal runaway, comprising a fixing part, an air duct and a measuring part, wherein the fixing part comprises a first fixing part and a second fixing part which are arranged opposite to each other, and the first fixing part and the second fixing part are connected to form a clamping fixation for the battery to be tested; the air duct is connected to the fixing part and is located at the position of the pressure relief valve of the battery to be tested, and the pressure relief valve of the battery to be tested is aligned with the air duct; the measuring part is connected to the air duct, and the pressure is measured by using the measuring part after the battery has thermal runaway, and the gas flow rate and gas production amount of the battery under thermal runaway are calculated. The test device has a simple structure, is convenient to process, is easy to operate and has a low cost, is suitable for batteries of different capacities, different sizes and different material systems, can accurately measure the gas flow rate and gas production amount of the battery under thermal runaway, and can be used in conjunction with equipment such as an adiabatic accelerating calorimeter, so as to provide technical support for researchers to design and develop high-safety batteries and thermal runaway protection products.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a device and method for measuring the gas flow rate and gas production amount of a battery during thermal runaway. Background Art

[0002] With the rapid development of the new energy vehicle industry, electric vehicle fire accidents have attracted more and more attention. These fire accidents are basically caused by thermal runaway of lithium batteries due to the abuse of lithium batteries. Therefore, it is necessary to conduct safety tests on lithium batteries. Among many safety test items, the thermal runaway gas production test of lithium batteries is one of the most important test items. This is because the key parameters of the thermal runaway test, such as pressure, temperature, gas production and gas flow rate (or gas production rate), are conducive to researchers to design and develop high-safety batteries and thermal runaway protection products, and help people more intuitively understand the hazards of thermal runaway of lithium batteries.

[0003] At present, the measurement devices for the characteristic parameters of the thermal runaway gas production process of lithium batteries are mainly based on two methods: the constant volume closed container measurement method and the mass loss measurement method. The constant volume closed container measurement method is to place the battery in a closed container, and then measure the pressure and temperature of the gas in the closed container, and under the assumption of ideal gas, obtain the gas production (volume) at different times according to the ideal gas state equation, and further obtain the volume gas production at different times. The mass loss measurement method is to fix the battery on an electronic scale, and then obtain the gas production (mass) at different times by measuring the mass of the battery during the thermal runaway process, and further obtain the mass gas production of the battery.

[0004] However, the gas production obtained by the constant volume closed container method has a spatial average property, so the disadvantage of this method is that it cannot well reflect the actual amount of gas erupting from the battery rupture, and the mass loss converted from the gas production is quite different from the actual mass loss, that is, there is an illusion of mass non-conservation. The disadvantage of the mass loss method is that it usually overestimates the gas production, and the violent eruption of the battery during thermal runaway will also cause inaccurate weighing on the electronic scale. In summary, although the existing measurement methods and devices for the characteristic parameters of the thermal runaway gas production process of lithium batteries have indeed helped researchers to reveal the laws of the thermal runaway gas production process of lithium batteries to a certain extent, there is still the problem of inaccurate measurement of the key parameter of gas production. Summary of the invention

[0005] The present invention provides a device and method for measuring the gas flow rate and gas production amount of a battery during thermal runaway, so as to solve the problem of inaccurate measurement of key parameters in the process of thermal runaway gas production test of lithium batteries in the prior art, and realize accurate measurement of the gas flow rate and gas production amount of the battery during thermal runaway.

[0006] The present invention provides a device for measuring the gas flow rate and gas production amount of a battery under thermal runaway, comprising a fixing part, an air guide pipe and a measuring part, wherein the fixing part comprises a first fixing part and a second fixing part arranged opposite to each other, and the first fixing part and the second fixing part are connected and installed in cooperation with each other to clamp and fix the battery to be measured;

[0007] The air guide tube is connected to the fixing member and is located at the position of the pressure relief valve of the battery to be tested, and the pressure relief valve of the battery to be tested is aligned with the air guide tube;

[0008] The measuring member is connected to the air guide tube.

[0009] The air duct is connected to the fixing member via a fixing plate, the fixing plate is fixedly connected to the first fixing member and the second fixing member, and a through hole for connecting the air duct is provided in the middle of the fixing plate.

[0010] At least one circle of sealing grooves is circumferentially arranged inside the air guide pipe, and a high temperature resistant sealing ring is installed in the sealing groove.

[0011] The measuring piece is a venturi tube, and pressure measuring heads are respectively arranged at the inlet of the contraction section of the venturi tube and the throat of the venturi tube, and pressure sensors are installed on the pressure measuring heads.

[0012] A protrusion is arranged on the outer wall of the venturi tube connected to the air guide tube, and a mounting groove matching with the protrusion is arranged on the inner wall of the air guide tube along the axial direction of the air guide tube.

[0013] The first fixing member and the second fixing member are metal shells, and an insulating layer is provided on the inner surfaces of the first fixing member and the second fixing member.

[0014] The insulating layer is an insulating coating or an insulating tape layer.

[0015] The first fixing member and the second fixing member both have through holes in their middles.

[0016] A method for measuring the gas flow rate and gas production amount of a battery during thermal runaway, using the above-mentioned device for measuring the gas flow rate and gas production amount of a battery during thermal runaway, comprises the following steps:

[0017] Step 1: placing the battery to be tested between the first fixing member and the second fixing member, installing and connecting the first fixing member and the second fixing member to clamp and fix the battery to be tested, and aligning the pressure relief valve of the battery to be tested with the air guide pipe;

[0018] Step 2: Apply high temperature resistant sealant to the gap between the fixing plate and the battery to be tested; install a high temperature resistant seal ring in the air duct, and assemble and connect the measuring piece Venturi tube to the air duct;

[0019] Step 3: generating gas inside the battery to be tested, opening the pressure relief valve of the battery to be tested, and further causing thermal runaway of the battery to be tested;

[0020] Step 4, measuring the pressure or pressure difference between the inlet of the contraction section of the Venturi tube and the cross section of the throat of the Venturi tube;

[0021] Step 5: Calculate the gas flow rate and gas production of the battery under test due to thermal runaway according to the measurement data obtained in step 4.

[0022] The means for performing step three is one of thermal radiation heating, ambient temperature rise, acupuncture, external short circuit, internal short circuit and overcharging.

[0023] The device for measuring the gas flow rate and gas production of a battery during thermal runaway provided by the present invention measures the pressure using a venturi tube after the battery undergoes thermal runaway, and calculates the gas flow rate and gas production of the battery during thermal runaway. The test device has a simple structure, is easy to manufacture, easy to operate and has low cost. It is suitable for batteries of different capacities, different sizes and different material systems, can accurately measure the gas flow rate and gas production of the battery during thermal runaway, and can be used in conjunction with equipment such as an adiabatic accelerating calorimeter (ARC), providing technical support for researchers to design and develop high-safety batteries and thermal runaway protection products. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of the overall structure of the device for measuring the gas flow rate and gas production amount of a battery during thermal runaway provided by the present invention;

[0026] Figure 2 It is a schematic diagram of the overall structure explosion of the device for measuring the gas flow rate and gas production amount of a battery thermal runaway provided by the present invention;

[0027] Figure 3 It is a schematic diagram of assembling the air guide tube, the fixing plate and the first fixing member provided by the present invention.

[0028] Reference numerals:

[0029] 1. Fixing piece; 2. Air guide tube; 3. Measuring piece; 4. Fixing piece;

[0030] 1-1, first fixing member; 1-2, second fixing member;

[0031] 3-1. Pressure measuring head. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0034] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0035] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0037] This embodiment provides a device for measuring the gas flow rate and gas production amount of a battery during thermal runaway. Figure 1 As shown, it includes a fixing member 1, an air duct 2 and a measuring member 3, the fixing member 1 includes a first fixing member 1-1 and a second fixing member 1-2 which are arranged opposite to each other, the first fixing member 1-1 and the second fixing member 1-2 are connected and installed in cooperation with each other to form a clamping fixation for the battery to be tested; the air duct 2 is connected to the fixing member 1 and is located at the position of the pressure relief valve of the battery to be tested, and the pressure relief valve of the battery to be tested is aligned with the air duct 2; the measuring member 3 is connected to the air duct 2.

[0038] See also Figure 1 As shown, the structure in this embodiment is suitable for measuring the gas flow rate and gas production of square batteries in thermal runaway, but the present invention is not limited to square batteries. Batteries of any shape can be measured by this device as long as they are fixed and the pressure relief valve is aligned with the air duct 2. The battery is thermally runaway by means of means, the pressure relief valve is opened, and the gas flow enters the measuring part 3 through the air duct 2 to measure the pressure, and the gas production is obtained by calculation. The test device has a simple structure, convenient processing, easy operation and low cost. It is suitable for batteries of different capacities, different sizes and different material systems, and can accurately measure the gas flow rate and gas production of batteries in thermal runaway.

[0039] See also Figure 2 and Figure 3 As shown, in this embodiment, the first fixing member 1-1 and the second fixing member 1-2 are metal shells, and the material can be but not limited to structural steel, stainless steel, etc., and the inner surfaces of the first fixing member 1-1 and the second fixing member 1-2 are provided with an insulating layer, and the insulating layer is an insulating coating, or it can be affixed with an insulating tape or other solutions to prevent the fixing member from causing a short circuit in the battery. Through holes are opened in the middle of the first fixing member 1-1 and the second fixing member 1-2 to prevent the battery expansion from causing a large deformation of the fixing member 1; in addition, screw holes are left on the fixing member 1, which are used in combination with screws, nuts, and washers to fix and clamp the battery.

[0040] In the structure of the present invention, the air duct 2 is connected to the fixing member 1 through a fixing plate 4, and the fixing plate 4 is fixedly connected to the first fixing member 1-1 and the second fixing member 1-2. A through hole for connecting the air duct 2 is provided in the middle of the fixing plate 4, and the fixing method between the fixing plate 4 and the air duct 2 can be but not limited to welding. There can be multiple specific connection methods for fixing the fixing plate 4 to the first fixing member 1-1 and the second fixing member 1-2. The simplest one is to respectively set slots on the first fixing member 1-1 and the second fixing member 1-2, and respectively set clamps corresponding to the slots on the first fixing member 1-1 and the second fixing member 1-2 at the upper end and the lower end of the fixing plate 4, so that the fixing plate 4 is connected to the first fixing member 1-1 and the second fixing member 1-2 through the matching installation of the clamp and the slot; considering that as long as the first fixing member 1-1 and the second fixing member 1-2 can be matched and installed, the fixing plate 4 can be welded and fixed to one of the first fixing member 1-1 and the second fixing member 1-2, and then connected to the other through the clamp slot.

[0041] The material of the air duct 2 can be but is not limited to structural steel, stainless steel, etc., and at least one circle of sealing grooves is arranged circumferentially inside the air duct 2, and a high temperature resistant sealing ring is installed in the sealing groove. The high temperature resistant sealing ring forms a high degree of sealing during the measurement process to ensure the accuracy of the measurement. In this embodiment, the measuring member 3 is preferably a venturi tube, and a protrusion is arranged on the outer wall of the venturi tube connected to the air duct 2, and a mounting groove that cooperates with the protrusion is arranged on the inner wall of the air duct 2 along the axial direction of the air duct 2. The venturi tube is connected to the air duct 2 through the protrusion and the mounting groove. The pressure measuring head 3-1 is respectively arranged at the inlet position of the contraction section of the venturi tube and the throat position of the venturi tube. A pressure sensor is installed on the pressure measuring head 3-1. The pressure or pressure difference of the cross section of the inlet position of the contraction section of the venturi tube and the throat position of the venturi tube is measured by two pressure sensors, and finally the gas flow rate and gas production of the battery thermal runaway are obtained by precise calculation.

[0042] The following is a description of the method for measuring the gas flow rate and gas production amount of a battery during thermal runaway provided by the present invention. The method for measuring the gas flow rate and gas production amount of a battery during thermal runaway described below and the device for measuring the gas flow rate and gas production amount of a battery during thermal runaway described above can be referenced to each other.

[0043] This embodiment provides a method for measuring the gas flow rate and gas production amount of a battery due to thermal runaway, using the above-mentioned device for measuring the gas flow rate and gas production amount of a battery due to thermal runaway, including the following steps:

[0044] Step 1: Place the battery to be tested between the first fixing member 1-1 and the second fixing member 1-2, and use materials and tools such as bolts, nuts, washers, and wrenches to install and connect the first fixing member 1-1 and the second fixing member 1-2 to clamp and fix the battery to be tested, and align the pressure relief valve of the battery to be tested with the air duct 2, and make corresponding seals, so that the gas discharged from the pressure relief valve of the battery to be tested enters the air duct 2 and is not discharged outside the air duct 2;

[0045] Step 2: Apply high temperature resistant sealant to the gap between the fixing plate 4 and the battery to be tested; install a high temperature resistant seal ring in the air duct 2, and assemble and connect the venturi tube to the air duct 2;

[0046] Step 3: through some abuse means (refer to the specific means described below for details), gas is generated inside the battery to be tested. When the gas generation reaches a certain level, the pressure relief valve of the battery to be tested is opened, and the battery to be tested is further caused to have thermal runaway;

[0047] Step 4, measuring the pressure or pressure difference between the inlet of the contraction section of the Venturi tube and the cross section of the throat of the Venturi tube;

[0048] Step 5: Calculate the gas flow rate and gas volume of the battery under test due to thermal runaway according to the measurement data obtained in step 4.

[0049] The pressure sensor measures the pressure values ​​at the inlet and throat sections of the venturi tube contraction section, and the gas flow rate is calculated based on the pressure, and the gas production volume is finally obtained. The specific calculation process is as follows:

[0050] The continuity equation and the total flow Bernoulli equation are listed for the cross sections at the inlet and throat of the venturi tube contraction section, respectively, and we can get:

[0051]

[0052] Wherein, V1 is the velocity of the fluid flowing through the inlet cross-section of the contraction section of the Venturi tube; V2 is the velocity of the fluid flowing through the throat cross-section of the Venturi tube; A1 is the area of ​​the inlet cross-section of the contraction section of the Venturi tube; A2 is the area of ​​the throat cross-section of the Venturi tube; P1 is the pressure of the fluid flowing through the inlet cross-section of the contraction section of the Venturi tube; P2 is the pressure of the fluid flowing through the throat cross-section of the Venturi tube; ρ is the fluid density (the density value of typical flue gas is taken as the fluid density value here); g is the acceleration of gravity; Z1 is the height of the center of the inlet cross-section of the contraction section of the Venturi tube relative to the ground; Z2 is the height of the center of the throat cross-section of the Venturi tube relative to the ground;

[0053] Combining equation 1 and equation 2 and eliminating V1, we get:

[0054]

[0055] Where d is the diameter of the throat section of the Venturi tube; D is the diameter of the inlet section of the contraction section of the Venturi tube.

[0056] Let ΔP = P1-P2. Then formula 3 can be simplified to

[0057] Thermal runaway gas volume flow rate Q v and thermal runaway gas mass flow rate Q m It can be obtained through the following calculation:.

[0058]

[0059] Correspondingly, the thermal runaway gas volume v and gas mass m can be calculated based on the thermal runaway gas volume flow rate Q v and thermal runaway gas mass flow rate Q m The integral of the test time t is calculated separately:

[0060] <![CDATA[v=∫Q v dt]]> Formula 6 <![CDATA[m=∫Q m dt]]> Formula 7

[0061] Substituting equation 4 into equation 6, the volume v of the gas produced by thermal runaway can be obtained through calculation. Substituting equation 5 into equation 7, the mass m of the gas produced by thermal runaway can be obtained through calculation. Among them, ρ takes the density value of typical flue gas as the fluid density value here. It can also measure the gas composition and compare the composition to take the density of the same gas as it as the density value here. The pressure P1 of the fluid flowing through the inlet cross-section of the contraction section of the Venturi tube, the pressure P2 of the fluid flowing through the throat cross-section of the Venturi tube, the height Z1 of the center of the inlet cross-section of the contraction section of the Venturi tube relative to the ground, the height Z2 of the center of the throat cross-section of the Venturi tube relative to the ground, the diameter D of the inlet cross-section of the contraction section of the Venturi tube, and the diameter d of the throat cross-section of the Venturi tube are all known quantities.

[0062] The volume v of thermal runaway gas and the mass m of thermal runaway gas are the battery thermal runaway gas flow rate and gas production to be measured. By measuring the thermal runaway gas flow rate and gas production of a battery under thermal runaway, the safety performance and safety factor of batteries of the same specifications can be further understood.

[0063] In the above method, the means to cause step three to occur include but are not limited to thermal radiation heating, ambient temperature rise, acupuncture, external short circuit, internal short circuit and overcharging, which are described in detail below.

[0064] The preparations before the operation are as follows. (1) Photographing and recording: Before and after the test, the physical parameters of the battery, such as mass, size, voltage, internal resistance, etc., need to be measured, and the above-mentioned battery physical parameters, various surfaces of the battery, and details of concern need to be photographed and recorded. (2) Battery capacity calibration: Before the thermal runaway test, the battery needs to be calibrated. The capacity calibration method is: at 22℃±5℃, discharge the battery in CC mode, then let it stand for 60 minutes, then charge the battery in CC-CV mode, and then let it stand for 60 minutes; repeat the above steps 4 times, take the 4th discharge capacity as the nominal capacity, and record it as C0. (3) Adjust the battery SOC: If the thermal runaway gas production flow rate is measured under different states of charge (State of Charge, SOC), and the target state of charge is recorded as SOC obj , then the discharge capacity C is (100% - SOC obj )*C0, therefore, the method to adjust the battery SOC is: at 22℃±5℃, discharge the battery in CC mode, the discharge amount is C, and then let it stand for 60 minutes. It should be noted that the discharge current for adjusting the battery SOC should be based on C0 as a reference. (4) Arrange the measurement harness: Arrange thermocouples at the center of the front of the battery and voltage monitoring lines at the positive and negative electrodes of the battery to monitor the temperature of the center of the front of the battery and the battery voltage.

[0065] An embodiment of the present invention for causing a battery to have thermal runaway is to trigger thermal runaway by overcharging. The specific method is as follows: a fully charged battery (100% SOC) is charged at a constant current of 1C until the battery explosion relief valve opens and thermal runaway occurs, and then charging is stopped. During the test, a measuring device records in real time the pressure of the gas passing through the inlet and throat section of the contraction section.

[0066] Another embodiment of the present invention that causes thermal runaway of a battery triggers thermal runaway by acupuncture. The specific method is as follows: draw two diagonal lines on the large surface of the battery with a SOC of 75%, determine the acupuncture point in the center of the large surface, and then install the measuring device and arrange the measuring harness. After completing the preparations before the test, place the battery on the acupuncture machine to ensure that the needle tip points to the acupuncture point. The acupuncture test uses a steel needle with a cone angle of 20° to 45°, a diameter of 5mm, and a length of 150mm. Start the acupuncture machine, and the steel needle pierces the center of the large surface at a speed of 25mm / s until the battery's explosion relief valve opens and thermal runaway occurs, then stop acupuncture. During the test, the measuring piece records the pressure of the gas passing through the inlet and throat section of the contraction section in real time.

[0067] Another embodiment of the present invention that causes thermal runaway of the battery triggers thermal runaway by means of environmental temperature rise. The specific method is as follows: after completing the preparatory work before the test, place the battery with 50% SOC in an incubator, and then start the incubator. The incubator is heated to 130℃±2℃ at a rate of 5℃ / min and maintained for 2h; if the battery does not experience thermal runaway, the incubator continues to heat at a rate of 5℃ / min, and the temperature is maintained for 1h every time it rises by 5℃, until the battery experiences thermal runaway and the incubator stops heating. During the test, the measuring piece records the pressure of the gas passing through the inlet and throat section of the contraction section in real time.

[0068] Another embodiment of the present invention that causes thermal runaway of a battery triggers thermal runaway through ARC, and the specific method is as follows: after completing the preparatory work before the test, place a battery with 100% SOC into the ARC, and then start the ARC. The ARC heats up at a rate of 2°C / min, and stops heating every time the temperature rises by 5°C. After the temperature of the battery and the shell are consistent, the ARC starts the "search" working mode. If ARC finds that the battery temperature rise is not less than 0.02°C / s, it is determined that the battery begins to self-heat and enters the "adiabatic tracking" working mode until the battery has thermal runaway and stops heating. During the test, the measuring piece records the pressure of the gas passing through the inlet and throat section of the contraction section in real time, and ARC measures and records parameters such as the ambient temperature and the battery self-heating temperature.

[0069] Another embodiment of the present invention that causes thermal runaway of a battery triggers thermal runaway by heating with a heating plate. The specific method is as follows: select a heating plate with a peak heating power of 900W that is substantially the same size as the battery, connect the heating plate to a heating power source, and then turn on the power for a few seconds to test whether the heating plate can work normally. After confirming that the heating plate can work normally and the temperature of the heating plate returns to room temperature, fix the heating plate on a battery with a 25% SOC with a high-temperature resistant tape or other material (a thermocouple can be arranged at the center of the contact surface between the heating plate and the battery during the process of fixing the heating plate). Then install the measuring device and arrange the measuring harness. After completing the above procedures, start the heating power source, and the heating plate heats the battery at a constant power of 900W until the battery has an explosion relief valve that opens and thermal runaway occurs. Then turn off the heating power source. During the test, the measuring piece records the pressure of the gas passing through the inlet and throat section of the contraction section in real time.

[0070] In summary, the device for measuring the gas flow rate and gas production of a battery during thermal runaway provided by the present invention measures the pressure using a venturi tube after the battery undergoes thermal runaway, and calculates the gas flow rate and gas production of the battery during thermal runaway. The test device has a simple structure, is easy to process, easy to operate and has low cost. It is suitable for batteries of different capacities, different sizes and different material systems, can accurately measure the gas flow rate and gas production of a battery during thermal runaway, and can be used in conjunction with equipment such as an adiabatic accelerating calorimeter (ARC), providing technical support for researchers to design and develop high-safety batteries and thermal runaway protection products.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for measuring the gas flow rate and gas production amount of a battery thermal runaway, characterized in that: include: A fixing member (1), the fixing member (1) comprising a first fixing member (1-1) and a second fixing member (1-2) arranged opposite to each other, the first fixing member (1-1) and the second fixing member (1-2) being connected and installed in cooperation with each other to clamp and fix the battery to be tested; slots are respectively arranged on the first fixing member (1-1) and the second fixing member (1-2), and through holes are opened in the middle of the first fixing member (1-1) and the second fixing member (1-2); An air duct (2), the air duct (2) being connected to the fixing member (1) through a fixing plate (4) and being located at the position of the pressure relief valve of the battery to be tested, the pressure relief valve of the battery to be tested being aligned with the air duct (2); the fixing plate (4) being fixedly connected to the first fixing member (1-1) and the second fixing member (1-2), a through hole for connecting the air duct (2) being provided in the middle of the fixing plate (4), and clamps corresponding to the slots on the first fixing member (1-1) and the second fixing member (1-2) being provided at the upper end and the lower end of the fixing plate (4), respectively, and the fixing plate (4) is connected to the first fixing member (1-1) and the second fixing member (1-2) by the matching installation of the clamps and the slots; A measuring piece (3), wherein the measuring piece (3) is connected to the airway tube (2).

2. The device for measuring gas flow and gas production of battery thermal runaway according to claim 1, characterized in that: At least one circle of sealing grooves is circumferentially arranged inside the air guide pipe (2), and a high temperature resistant sealing ring is installed in the sealing groove.

3. The device for measuring the gas flow rate and gas production amount of a battery due to thermal runaway according to claim 1, characterized in that: The measuring member (3) is a Venturi tube, and pressure measuring heads (3-1) are respectively arranged at the inlet position of the contraction section of the Venturi tube and the throat position of the Venturi tube, and a pressure sensor is installed on the pressure measuring head (3-1).

4. The device for measuring the gas flow rate and gas production amount of a battery due to thermal runaway according to claim 3, characterized in that: A protrusion is provided on the outer wall of the venturi tube connected to the air guide tube (2), and a mounting groove cooperating with the protrusion is arranged on the inner wall of the air guide tube (2) along the axial direction of the air guide tube (2).

5. The device for measuring the gas flow rate and gas production amount of a battery thermal runaway according to claim 1, characterized in that: The first fixing member (1-1) and the second fixing member (1-2) are metal shells, and an insulating layer is provided on the inner surfaces of the first fixing member (1-1) and the second fixing member (1-2).

6. The device for measuring the gas flow rate and gas production amount of a battery due to thermal runaway according to claim 5, characterized in that: The insulating layer is an insulating coating or an insulating tape layer.

7. A method for measuring the gas flow rate and gas production of a battery due to thermal runaway, characterized in that: The device for measuring the gas flow rate and gas production amount of a battery during thermal runaway as described in any one of claims 1 to 6 comprises the following steps: Step 1: placing the battery to be tested between the first fixing member (1-1) and the second fixing member (1-2), installing and connecting the first fixing member (1-1) and the second fixing member (1-2) to clamp and fix the battery to be tested, and aligning the pressure relief valve of the battery to be tested with the air guide pipe (2); Step 2: Apply high temperature resistant sealant to the gap between the fixing plate (4) and the battery to be tested; A high temperature resistant sealing ring is installed in the air guide pipe (2), and the measuring piece (3) and the venturi tube are assembled and connected to the air guide pipe (2); Step 3: generating gas inside the battery to be tested, opening the pressure relief valve of the battery to be tested, and further causing thermal runaway of the battery to be tested; Step 4, measuring the pressure or pressure difference between the inlet of the contraction section of the Venturi tube and the cross section of the throat of the Venturi tube; Step 5: Calculate the gas flow rate and gas production of the battery under test due to thermal runaway according to the measurement data obtained in step 4.

8. The method for measuring the gas flow rate and gas production amount of a battery due to thermal runaway according to claim 7, characterized in that: The means for performing step three is one of thermal radiation heating, ambient temperature rise, acupuncture, external short circuit, internal short circuit and overcharging.

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