A testing device and testing platform for lithium battery separator pore closure and fusing

Abstract

The utility model relates to a kind of lithium battery diaphragm closed hole and fuse testing device, it sequentially includes: exhaust passage, upper air cavity, metal disc, lower air cavity, air inlet, the metal disc is equipped with through air groove structure, it extends from the central region of the metal disc to the spiral trajectory extension of outer peripheral portion, temperature and pressure sensing component is also provided in the exhaust passage, it includes movable temperature sensing piece and bias sensing piece, wherein, the bias sensing piece can exert bias force to the movable temperature sensing piece, so that the movable temperature sensing piece is relative to the upper air cavity telescopic;In the utility model, the through air groove structure of spiral configuration makes high-pressure gas pass uniformly, and integrates movable temperature sensing piece and bias sensing piece, while monitoring diaphragm temperature and pressure change, to characterize its closed hole and fuse temperature point in real time.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery separator testing, specifically a device and testing platform for testing the pore-closure and melting of lithium battery separators. Background Technology

[0002] Lithium-ion batteries have become the mainstream of power battery development. Although they have advantages such as high specific energy, wide operating temperature range, and stable discharge, various safety hazards still exist. The pore-closing temperature and melting temperature of the separator are important indicators to ensure the safety of lithium-ion batteries. The main components of existing lithium batteries are positive electrode, negative electrode, electrolyte, and separator. The role of the separator is to separate the positive and negative electrodes. It allows ions to pass through but prevents electrons from passing through, so as to prevent the positive and negative electrode plates from directly contacting each other and causing a short circuit. Its performance determines the interface structure and internal resistance of the battery, thereby affecting the battery performance such as capacity, cycle period, and charge / discharge current density.

[0003] Because the separator's structure mainly consists of numerous micropores, with pore sizes generally below 1μm, if a short circuit occurs inside the battery, the accumulated heat causes the internal temperature to rise rapidly. The separator's micropores will slowly close, increasing the battery's internal resistance. Once the separator's micropores are completely closed, the reactions between the positive and negative electrodes will completely stop, thereby controlling the battery's internal temperature, preventing "thermal runaway," and stopping safety accidents such as lithium battery explosions or fires. The separator's pore-closing temperature must be within an appropriate range and higher than the ambient temperature at which the battery is used to ensure normal battery operation.

[0004] In extreme situations, if the internal temperature of the battery is too high, the separator may melt, causing the micropores to close and the internal temperature to rise further. After the separator melts, its viscosity decreases, causing it to rupture and the electrodes to come into direct contact, which can be dangerous. Therefore, it is essential to keep the separator intact above the melting temperature and avoid excessive thermal shrinkage. The higher the separator melting temperature, the longer it can prevent ion flow and the higher the safety.

[0005] Generally speaking, air permeability testing can indirectly reflect the pore state and internal resistance parameters of the diaphragm; however, the current air permeability tester cannot reflect the temperature points of diaphragm closure and melting in real time, making it difficult to determine the critical temperature at which closure and melting occur. Utility Model Content

[0006] In view of the shortcomings of the prior art described above, this utility model attempts to characterize the pore-closure and melting temperature points of the separator in real time by monitoring the changes in surface temperature and pressure. To this end, one aspect of this utility model provides a testing device for the pore-closure and melting of a lithium battery separator, comprising: an exhaust channel; an upper air chamber connected to one end of the exhaust channel; a lower air chamber disposed on one side of the upper air chamber relative to the exhaust channel; an air inlet channel disposed on one side of the lower air chamber relative to the upper air chamber, one end of which is connected to the lower air chamber; and a metal disc detachably disposed between the upper air chamber and the lower air chamber. The metal disk is provided with a through-slot structure, which extends in a spiral trajectory from the central region of the metal disk to the outer periphery; and a temperature and pressure sensing component is disposed in the exhaust passage, comprising: a movable temperature sensor disposed adjacent to the metal disk; and a bias sensor, one end of which is connected to the movable temperature sensor and the other end of which is fixed to the top of the upper air chamber, wherein the bias sensor is configured to apply a bias force toward the metal disk to the movable temperature sensor, thereby causing the movable temperature sensor to extend or retract relative to the upper air chamber.

[0007] As described above, the test device for the pore closure and melting of lithium battery separators includes a plurality of air holes in the through-hole structure, which are arranged sequentially at intervals along the spiral trajectory, wherein the diameter of the air holes is the same.

[0008] As described above, the lithium battery separator pore and fusion test device, wherein the through-hole structure is a continuous through-hole extending along the spiral trajectory, wherein the width of the continuous through-hole is the same along the spiral trajectory.

[0009] As described above, in the test apparatus for the pore closure and melting of lithium battery separators, the side of the metal disk facing the upper air chamber protrudes from the top of the lower air chamber.

[0010] As described above, the lithium battery separator pore closure and melting test device is provided with a first funnel-shaped air chamber in the upper air chamber.

[0011] As described above, the lithium battery separator pore closure and melting test device has a second funnel-shaped air chamber corresponding to the first funnel-shaped air chamber in the lower air chamber.

[0012] The lithium battery separator pore closure and melting test device described above further includes a heater connected to the lower air chamber, wherein the heater is selected from the group consisting of a silicone heater, a polyimide heating film, a resistance heating strip, a ceramic heater, a PTC heater, and a ring heater.

[0013] As described above, the test device for lithium battery separator pore closure and melting includes a movable temperature sensing element equipped with a contact temperature sensing component, which is at least one of a thermocouple, a platinum resistance temperature sensor, or a thermistor.

[0014] As described above, the lithium battery separator pore closure and melting test device includes a bias sensing element comprising a bias mechanism, one end of which is connected to the movable temperature sensing element, including at least one of an elastic bias element, a fluid pressure bias element, a magnetic bias element, or a gravity bias element; and a pressure sensor comprising: a sensing end connected to the bias mechanism and configured to generate a pressure signal in response to pressure changes in the bias mechanism; and a transmitting end, one end of which is connected to the sensing end and the other end of which is connected to the top of the upper air chamber, configured to transmit the pressure signal.

[0015] Another aspect of this utility model provides a test platform for the pore closure and melting of lithium battery separators, comprising: a calculator; a base for supporting the calculator; a sample stage disposed above the calculator relative to the base; a test device for the pore closure and melting of lithium battery separators as described above, disposed on the sample stage; and a drive mechanism disposed on the sample stage, comprising: a drive arm and a motor, wherein one end of the drive arm is connected to the test device and the other end is connected to the motor, and the motor is signal-connected to the calculator, wherein: the lower air chamber is fixed to the sample stage, and the drive arm is connected to the upper air chamber; during the test phase, the drive arm is driven by the motor to make the upper air chamber and the lower air chamber fasten together.

[0016] As described above, this invention utilizes a spirally configured through-hole structure to allow high-pressure gas to pass through more evenly, and the upper air chamber tightly fits the lower air chamber to ensure that the diaphragm under test is tightly adhered, thereby ensuring the accuracy of the data read by the testing device. In addition, this invention is also equipped with a calculator to read the temperature and pressure information returned by the temperature and pressure sensing components in real time and to further process the data.

[0017] The testing device provided by this utility model is compact. A spiral-shaped through-slot structure on the metal disc ensures uniform pressure on the sample under test and guarantees a constant heating rate. A movable temperature sensor and a bias sensor are installed in the exhaust channel of the upper air chamber to ensure complete contact between the movable temperature sensor and the sample during testing, reducing the error rate of temperature information. Furthermore, the multiple exhaust channels allow multiple temperature sensing components to simultaneously test the sample, monitoring the surface temperature of the sample. Simultaneously, the bias sensor can apply pressure to the diaphragm, reducing the diaphragm's contraction during heating and allowing for real-time monitoring of pressure changes during diaphragm contraction. Attached Figure Description

[0018] Figure 1The diagram shows the structure of a test device for testing the pore closure and melting of a lithium battery separator. Figure 2 It is shown as a through-hole structure with air holes arranged at intervals on a metal disk; Figure 3 Displayed as a continuous through-hole structure on a metal disk; Figure 4 The diagram shows the structure of a test platform for testing the pore closure and melting of a lithium battery separator. Detailed Implementation

[0019] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0020] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and objectives of this utility model, should still fall within the scope of the technical content disclosed in this utility model. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this utility model.

[0021] Please see Figures 1 to 3The first embodiment of this utility model is a testing device 100 for the pore closure and melting of a lithium battery separator, comprising: an exhaust duct 1; an upper air chamber 2 internally connected to the exhaust duct 1; a lower air chamber 3 disposed on one side of the upper air chamber 2 relative to the exhaust duct 1; an air inlet duct 4 disposed inside the lower air chamber 3 relative to the upper air chamber 2 and connected to the interior of the lower air chamber 3; and a metal disk 5 detachably disposed between the upper air chamber 2 and the lower air chamber 3, wherein the metal disk 5 has a through-slot structure 51, the through-slot structure 51 extending in a spiral trajectory from the central region C of the metal disk 5 to the outer periphery O; and a temperature and pressure sensor. Component 6, which passes through the exhaust duct 1, includes: a movable temperature sensor 61 disposed adjacent to the metal disk 5; and a bias sensing element 62, one end of which is connected to the movable temperature sensor 61 and the other end is fixed to the top of the upper air chamber 2. The bias sensing element 62 is configured to apply a bias force toward the metal disk 5 to the movable temperature sensor 61, thereby causing the movable temperature sensor 61 to extend and retract relative to the upper air chamber 2. In this way, the movable temperature sensor 61 can contact the sample 8 to be tested for temperature change sensing, and the pressure change of the sample 8 to be tested is sensed by the bias sensing element 62, thus simultaneously recording the temperature and pressure changes of the diaphragm surface in the air chamber.

[0022] In some embodiments, such as Figure 2 As shown, the through-hole structure 51 includes a plurality of air holes 510, which are arranged sequentially at intervals along a spiral trajectory extending from the central region C to its outer periphery O, wherein the diameter of the air holes 510 is the same.

[0023] In other embodiments, the through-slot structure 51 is a continuous through-slot extending along the spiral trajectory, wherein the width of the continuous through-slot is the same along the spiral trajectory.

[0024] In several embodiments, the side of the metal disk 5 facing the upper air chamber 2 protrudes from the top of the lower air chamber 3; it is understood that when the upper air chamber 2 and the lower air chamber 3 are closed relative to each other, the protruding metal disk 5 can flatten the diaphragm sample to ensure that the diaphragm sample is subjected to uniform force.

[0025] In several embodiments, the upper air chamber 2 is provided with a first funnel-shaped air chamber 21, configured to contain high-pressure gas from the lower air chamber 3 through the through-hole structure 51.

[0026] In several embodiments, the lower air chamber 3 is provided with a second funnel-shaped air chamber 31 corresponding to the first funnel-shaped air chamber 21; in principle, the dimensions of the first funnel-shaped air chamber 21 and the second funnel-shaped air chamber 31 are basically the same.

[0027] In several embodiments, the testing device 100 further includes a heater 7 connected to the lower air chamber 3, wherein the heater 7 may be a silicone heater, a polyimide heating film, a resistance heating strip, a ceramic heater, a PTC heater, or a ring heater.

[0028] In some embodiments, the movable temperature sensing element 61 is a contact temperature sensing component, which is at least one of a thermocouple, a platinum resistance temperature sensor, or a thermistor.

[0029] In some embodiments, please continue reading Figure 1 The bias sensing element 62 includes a bias mechanism 621 and a pressure sensor 622. One end of the bias mechanism 621 is connected to the movable temperature sensing element 61. The pressure sensor 622 includes a sensing end and a transmitting end. The sensing end is connected to the bias mechanism 621 and configured to generate a pressure signal in response to pressure changes in the bias mechanism 621. One end of the transmitting end is connected to the sensing end, and the other end is connected to the top of the upper air chamber 2, configured to send the pressure signal. In a preferred embodiment, the bias mechanism 621 includes at least one of an elastic bias element, a fluid pressure bias element, a magnetic bias element, or a gravity bias element, which generates a pressure change signal through displacement changes of the bias sensing element body.

[0030] The second embodiment of this utility model provides a test platform 200 for lithium battery separator pore closure and melting, such as... Figure 4 As shown, it includes: a calculator 201; a base 202 for carrying the calculator 201; a sample stage 203 disposed above the calculator 201 relative to the base 202; a lithium battery separator pore closure and melting test device 100 as described in the first embodiment, disposed on the sample stage 203; and a drive mechanism 204 disposed on the sample stage 203, which includes: a drive arm 204a and a motor 204b, wherein one end of the drive arm 204a is connected to the test device 100 and the other end is connected to the motor 204b, and the motor 204b is signal-connected to the calculator 201, wherein: the lower air chamber 3 is fixed to the sample stage 203, and the drive arm 204a is connected to the upper air chamber 2. During the test phase, the drive arm 204a is driven by the motor 204b to make the upper air chamber 2 and the lower air chamber 3 fasten together.

[0031] Please see Figure 1The following describes the operation of this utility model in detail: The diaphragm is cut into a sample 8 to be tested with an area greater than 5*5cm and placed on the metal disk 5 to cover the through-hole structure 51 leading to the lower air chamber 3; the calculator 201 is started, and the motor 204b is controlled by software to drive the drive arm 204a to drive the upper air chamber 2 to lock the lower air chamber 3; the sample 8 to be tested naturally adheres to the metal disk 5, and the edge of the upper air chamber 2 is pressed to compact the sample 8 to be tested; the movable temperature sensor 61 is configured with a contact temperature sensing component, and under the bias force provided by the bias sensing component 62 towards the metal disk 5, it contacts the surface of the sample 8 to be tested; and air is introduced through the air passage 4. High-pressure gas, with a pressure value between 4 kPa and 110 kPa; heater 7 continuously heats the lower gas chamber 3, for example, at a rate of 5°C / min, 10°C / min or 20°C / min, up to 200°C, to perform the closed-cell and melting tests on the sample 8 to be tested; throughout the test process, the temperature and pressure sensing signals of the movable temperature sensor 61 and the bias sensor 62 are transmitted back to the calculator 201 in real time, and the monitoring software draws images so that the operator can perform visual analysis; after the test is completed, the diaphragm residue in the upper gas chamber 2 is removed, and the test device 100 is allowed to cool down on its own.

[0032] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A testing device for the pore-closure and melting of a lithium battery separator, characterized in that, It includes: Exhaust duct; The upper air chamber is connected to one end of the exhaust passage; The lower air chamber is disposed on one side of the upper air chamber relative to the exhaust passage; An air intake is disposed on one side of the lower air chamber relative to the upper air chamber, with one end connected to the lower air chamber; A metal disc, detachably disposed between the upper air chamber and the lower air chamber, wherein the metal disc has a through-slot structure, the through-slot structure extending in a spiral trajectory from the central region of the metal disc to the outer periphery; and A temperature and pressure sensing component, disposed within the exhaust duct, includes: A movable temperature sensor is disposed adjacent to the metal disc; and A bias sensing element, one end of which is connected to the movable temperature sensing element and the other end of which is fixed to the top of the upper air chamber, wherein the bias sensing element is configured to apply a bias force toward the metal disk to the movable temperature sensing element, thereby causing the movable temperature sensing element to extend or retract relative to the upper air chamber.

2. The testing device for lithium battery separator pore closure and melting as described in claim 1, characterized in that, The through-hole structure includes a plurality of air holes, which are arranged sequentially at intervals along the spiral trajectory, wherein all air holes have the same diameter.

3. The testing device for lithium battery separator pore closure and melting as described in claim 1, characterized in that, The through-slot structure is a continuous through-slot extending along the spiral trajectory, wherein the width of the continuous through-slot is the same along the spiral trajectory.

4. The testing device for lithium battery separator pore closure and melting as described in claim 3, characterized in that, The side of the metal disc facing the upper air chamber protrudes from the top of the lower air chamber.

5. The testing apparatus for lithium battery separator pore closure and melting as described in claim 1, characterized in that, The upper air chamber is provided with a first funnel-shaped air chamber.

6. The testing apparatus for lithium battery separator pore closure and melting as described in claim 5, characterized in that, The lower air chamber is provided with a second funnel-shaped air chamber corresponding to the first funnel-shaped air chamber.

7. The testing apparatus for lithium battery separator pore closure and melting as described in claim 1, characterized in that, The testing device further includes a heater connected to the lower air chamber, wherein the heater is selected from the group consisting of a silicone heater, a polyimide heating film, a resistance heating strip, a ceramic heater, a PTC heater, and a ring heater.

8. The testing apparatus for lithium battery separator pore closure and melting as described in claim 1, characterized in that, The movable temperature sensor is provided with a contact temperature sensing component, which is at least one of a thermocouple, a platinum resistance temperature sensor, or a thermistor.

9. The testing apparatus for lithium battery separator pore closure and melting as described in claim 1, characterized in that, The bias sensing element includes: A biasing mechanism, one end of which is connected to the movable temperature sensor, includes at least one of an elastic biasing element, a fluid pressure biasing element, a magnetic biasing element, or a gravity biasing element; and Pressure sensor, including: The sensing end is connected to the bias mechanism and configured to generate a pressure signal in response to pressure changes in the bias mechanism. The transmitting end is connected at one end to the sensing end and at the other end to the top of the upper air chamber, and is configured to send the pressure signal.

10. A test platform for the pore-closure and melting of lithium battery separators, characterized in that, include: calculator; The base carries the calculator; The sample stage is positioned above the calculator relative to the base. ； The testing apparatus for the pore closure and melting of lithium battery separators as described in any one of claims 1 to 9 is disposed on the sample stage; A driving mechanism, disposed on the sample stage, includes: A drive arm and a motor, wherein one end of the drive arm is connected to the testing device, and the other end is connected to the motor, and the motor is signal-connected to the calculator, wherein: The lower air chamber is fixed to the sample stage, and the drive arm is connected to the upper air chamber. During the testing phase, the drive arm is driven by the motor to make the upper air chamber and the lower air chamber fasten together.

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