A method and device for detecting the performance of a battery separator

Abstract

The present invention relates to a method and device for detecting the performance of a battery separator, belonging to the technical field of lithium-ion batteries. The device used includes a pipeline, a thermocouple, a temperature monitoring device, a flow monitoring device, a gas cylinder, a fixture, a pneumatic valve, etc. The separator sample forms a closed surface in the pipeline through the fixture. During the heating process, the flow monitoring device, the temperature monitoring device and the thermocouple monitor and record the flow rate and the body surface temperature of the separator in real time. By adjusting the flow rate of the second fluid outlet, the flow rate of the fluid inlet is always kept at V0, and at the same time, the flow rate V1 of the first fluid outlet is recorded; a temperature-fluid outlet flow rate percentage curve is plotted, and the temperatures corresponding to the points where the fluid outlet flow rate suddenly drops and suddenly rises are used as the initial closing temperature and the initial film-breaking temperature of the separator sample; the number of steps of the fluid outlet flow rate drop is used as the closing temperature and temperature distribution of different pore sizes. The present invention is simple and convenient, and at the same time has high safety, strong practicability and high accuracy.

Description

Technical Field

[0001] The present invention relates to a method and device for detecting the performance of a battery separator, specifically a method and device for testing the performance of a lithium-ion battery separator, and belongs to the technical field of lithium-ion batteries. Background Art

[0002] With the increasingly severe energy crisis and environmental pollution problems, lithium-ion batteries, as a new generation of green energy storage devices, have been widely used. However, safety issues have always been an important factor restricting their development. The separator is one of the four key materials that make up a lithium-ion battery. It is mainly used to isolate the positive and negative electrode materials, prevent internal short circuits from forming, and allow lithium ions to pass through freely. The quality of the separator characteristics has an important impact on the performance of lithium-ion batteries such as rate performance, cycle life, and safety. Among them, the closure temperature and breakdown temperature of the separator are important characteristics and also important indicators to ensure the safety performance of lithium-ion batteries. When there is an internal short circuit in the battery, a violent electrochemical reaction will generate a large amount of Joule heat. When the closure temperature of the separator is reached, it will shrink and close the pores by itself to hinder the passage of lithium ions, causing the internal resistance of the battery to rise sharply, thereby avoiding further thermal runaway. Therefore, it is of great significance to select a separator with an appropriate closure temperature to ensure the safety of the battery. When the internal short circuit is not effectively contained, the internal temperature further rises. Once the melting temperature is reached, the separator will melt and rupture, resulting in direct contact short circuit between the positive and negative electrodes, and there may be risks such as explosion. It can be seen that increasing the breakdown temperature of the separator is also an inevitable requirement to ensure the safety of lithium-ion batteries. Therefore, simple and effective testing of the performance such as the closure temperature and breakdown temperature of the separator is of great significance for the safety of lithium-ion batteries.

[0003] Patent CN101625271A discloses a method and device for testing the closure temperature and breakdown temperature of a battery separator, which records the resistance change of the battery under heating conditions and judges the closure temperature and breakdown temperature of the separator based on the resistance mutation points on the temperature-resistance change curve. The method includes the following steps: making a button cell using the separator and electrolyte as the test battery; heating and raising the temperature of the test battery, and raising the ambient temperature from room temperature to 200°C; recording the temperature of the test battery and the resistance value corresponding to this temperature every 5 s; data processing, and plotting the temperature-resistance curve of the test battery. However, the electrolyte used in this method has certain toxicity; secondly, due to the relatively high closure temperature and breakdown temperature of the separator, the electrolyte will volatilize and decompose during this process. After the electrolyte decreases, the overall resistance will increase, which will inevitably have a greater impact on the test results.

[0004] Patent CN105738404A provides a method and device for testing the closed pore temperature and film breaking temperature of a lithium-ion battery separator. First, the separator sample is fixed at the open end of a pipeline, and the pipeline is placed in an oven and heated at a rate of 5-10 °C / min. At the same time, gas is introduced into the pipeline and made to pass through the separator sample at a uniform speed. Every 10 s, the temperature and pressure values are recorded simultaneously, and a temperature-pressure change curve is plotted. The temperature values corresponding to the points where the pressure value suddenly rises and suddenly drops as the temperature changes are the initial closed pore temperature and the initial film breaking temperature of the separator sample, respectively. The above steps are repeated at least three times, and the average value is used as the closed pore temperature and film breaking temperature of the separator. However, this method has certain deficiencies. When the separator closes pores at a certain temperature, the gas is blocked and difficult to pass through the separator. At this time, the gas still enters the measuring device at a certain flow rate and accumulates at the inlet, and the pressure on one side of the separator continuously increases. Between the closed pore temperature and the film breaking temperature, the separator is easily stretched into pores and broken under the increasing pressure, resulting in the measured film breaking temperature being lower than the actual film breaking temperature. The greater the difference between the closed pore temperature and the film breaking temperature, the greater the error in the test results. Summary of the Invention

[0005] The main object of the present invention is to provide a method for testing the performance of a lithium-ion battery separator, including the closed pore temperature, the film breaking temperature, and the distribution of closed pores and film breaking with different pore diameters during the process.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for detecting the performance of a battery separator includes the following steps:

[0008] (1) Cut out a separator sample of appropriate size and fix the separator sample in the pipeline to form a closed surface in the middle of the pipeline between the second fluid outlet and the first fluid outlet. One end of the pipeline is a fluid inlet, the other end is the first fluid outlet, and a second fluid outlet is provided on the side of the pipeline at the fluid inlet end.

[0009] (2) Control the fluid inlet flow rate to a constant value V0 through a flow monitoring device.

[0010] (3) Place the pipeline in a heating device and heat it to 300 °C at a certain speed.

[0011] (4) The flow monitoring device, the temperature monitoring device, and the thermocouple monitor and record the flow rate and the surface temperature of the separator in real time. When the separator closes pores or breaks the film, control the fluid amount passing through the surface of the separator by adjusting the flow rate of the second fluid outlet to always keep it at V0, and record the flow rate V1 at the first fluid outlet at the same time.

[0012] (5) Based on the process data, plot the curve of temperature - fluid outlet flow percentage (V1 / V0*100%) (i.e., the amount of fluid passing through the diaphragm) H = V1 / V0%;

[0013] (6) According to the temperature - fluid outlet flow percentage change curve, take the temperatures corresponding to the points where the fluid outlet flow suddenly drops and suddenly rises as the initial closing temperature and initial film - breaking temperature of the diaphragm sample; take the number of steps of the fluid outlet flow drop in the curve as the closing temperature and temperature distribution of different pore sizes;

[0014] (7) Repeat the above steps (1)-(6) at least three times, and take the average value of the measured initial closing temperature and initial film - breaking temperature as the closing temperature and film - breaking temperature of the diaphragm.

[0015] In step (2), the fluid used in the method of the present invention is air, nitrogen or any other non - toxic, harmless and safe gas. The fluid inlet flow rate can be adjusted according to the pressure resistance of the diaphragm. For example, the value range of the fluid inlet flow rate is 2 - 10 ml / s to avoid the influence of high pressure on the test results.

[0016] In step (3), the heating device is an oven; the heating rate is 3 - 5 °C / minute.

[0017] The diaphragm performance test method of the present invention adopts the method of increasing the second fluid outlet to adjust the flow rate on one side of the diaphragm, and also includes other methods that can adjust the flow rate stably. During the process, a thermocouple is used to measure and monitor the temperature of the diaphragm body, and other temperature acquisition methods can also be used. The fluid inlet and outlet structure can be in any form, such as a single - hole or multi - hole form to ensure uniform gas distribution.

[0018] The present invention can accurately and effectively analyze the closing temperature, film - breaking temperature of the diaphragm body and the distribution of closing and film - breaking of different pore sizes during the process.

[0019] Another object of the present invention is to provide a test device for the performance of a lithium - ion battery diaphragm. The device has a simple structure and strong practicability, and can accurately measure the closing temperature, film - breaking temperature of the diaphragm and the distribution of closing and film - breaking of different pore sizes during the process.

[0020] A detection device for the performance of a battery separator, comprising a pipeline, a thermocouple, a temperature monitoring device, a flow monitoring device, a gas cylinder, a fixture and a pneumatic valve, etc. The pipeline is divided into two sections. The separator sample is fixed between the two sections of the pipeline by a fixture, and the two ends of the pipeline are hermetically connected into one body through the fixture. The open end on one side of the pipeline is a fluid inlet, which is connected to the gas cylinder through a gas pipeline. The open end on the other side of the pipeline is a first fluid outlet; a second fluid outlet is provided on the side surface of the pipeline at the fluid inlet end; the separator sample forms a closed surface in the pipeline between the second fluid outlet and the first fluid outlet; the thermocouple is arranged at one end of the separator sample and is connected to the temperature monitoring device through a wire; the flow monitoring devices are respectively installed between the second fluid outlet and the separator sample and at the first fluid outlet.

[0021] The second fluid outlet is connected to a gas pipeline and a valve. The flow rate of the fluid discharged from the second fluid outlet is controlled by the valve, so that the amount of fluid passing through the surface of the separator sample is always kept as the fluid inlet flow rate V0.

[0022] The cross-section of the pipeline is square or rectangular.

[0023] The fixture includes upper and lower clamping plates and movable bolts. The upper and lower clamping plates have the same structure; the separator sample is placed between the upper and lower clamping plates and is fixed by tightening the movable bolts. The rubber sealing structure on the surface of the clamping plates plays a sealing role. The upper and lower clamping plates are buckled with each other to form a square or rectangular frame structure, whose shape is the same as the cross-section of the pipeline and whose size is mutually matched with the inner diameter size of the pipeline.

[0024] The upper clamping plate or the lower clamping plate of the fixture includes a metal main body and a sealing rubber structure. The sealing rubber structure is sleeved on the metal main body. The metal main body of the clamping plate includes a test frame and connecting parts connected to both sides of the test frame. A first opening of the metal main body is provided on the test frame, and a second opening of the metal main body is provided on the connecting part. The first opening of the metal main body is a separator test hole. During the test, the separator is fixed on the first opening of the metal main body, which is installed between the first fluid outlet and the second fluid outlet, and its size is mutually matched with the pipeline size. The second opening of the metal main body is matched with the movable bolt for fixing the separator. The sealing rubber structure includes a groove and an opening of the rubber structure; a groove is provided on one side of the sealing rubber structure, and the groove is annular; a rubber structure opening is provided in the middle of the sealing rubber structure, and the rubber structure opening is mutually matched with the first opening of the metal main body. The sealing rubber structure is sleeved on the test frame of the metal main body. The groove serves as the positioner for the first fluid outlet and the second fluid outlet during the feeding of the fixture and connects the two sections of the pipeline to ensure the sealing performance during the test. There is no groove on the other side of the sealing rubber structure, and the rest of the structure is completely the same on both sides.

[0025] The closed surface formed by the separator sample is perpendicular to the extension direction of the pipeline and parallel to the cross-section of the pipeline.

[0026] The thermocouple contacts with the fixture and transmits the temperature signal to the temperature monitoring device for detecting the temperature of the diaphragm sample.

[0027] The flow monitoring device is a flow sensor.

[0028] The pneumatic valve is connected to the pipeline to control the left and right movement of the pipeline for loading and unloading the diaphragm fixture.

[0029] During the diaphragm loading process, the non-grooved sides of the upper and lower clamping plates of the diaphragm fixture are adjacent to the diaphragm, and the grooved sides of the upper and lower clamping plates of the diaphragm fixture are used for sealing and connecting two sections of the pipeline; the rubber sealing structure on the surface of the diaphragm fixture plays a sealing role. The pneumatic valve is connected to the pipeline and can control the pipeline to move left and right, so that the two sections of the pipeline are respectively moved to both sides of the fixture, pressed and sealed, or moved away from both sides of the fixture to facilitate the loading and unloading of the diaphragm fixture.

[0030] The steps of detecting by using this detection device include:

[0031] (1) First, place the diaphragm sample between the upper and lower clamping plates of the fixture, tighten the bolts to fix the diaphragm;

[0032] (2) Load the diaphragm fixture and fix and seal the diaphragm in the device through the pneumatic valve;

[0033] (3) Set the temperature and flow rate and conduct diaphragm detection;

[0034] (4) After the test is completed, remove the diaphragm fixture.

[0035] Advantages of the present invention:

[0036] The present invention uses the flow mutation method to test the closed-hole temperature, film-breaking temperature of the diaphragm body and the distribution of closed holes and film-breaking with different pore diameters during the process. The test steps are simple and convenient; at the same time, the use of toxic and harmful electrolytes is avoided during the process, with high safety, strong practicability and high accuracy.

[0037] The following further illustrates the present invention through the drawings and specific embodiments, but it does not mean to limit the protection scope of the present invention. Description of the Drawings

[0038] Figure 1 It is a schematic structural diagram of the battery diaphragm test device of the present invention.

[0039] Figure 2-1 It is a schematic view of surface A of the upper clamping plate or lower clamping plate structure of the diaphragm fixture.

[0040] Figure 2-2 It is a schematic view of surface B of the upper clamping plate or lower clamping plate structure of the diaphragm fixture.

[0041] Figure 3 The temperature-fluid outlet flow percentage curve drawn by using the method of the present invention.

[0042] Description of main reference numerals:

[0043] 1 Diaphragm test device 2 Fluid inlet

[0044] 3 First fluid outlet 4 Second fluid outlet

[0045] 5 Diaphragm sample 6 Thermocouple

[0046] 7 Temperature monitoring device 8 Flow monitoring device

[0047] 9 Upper or lower splint 10 Metal body

[0048] 11 First opening of the metal body 12 Second opening of the metal body

[0049] 13 Sealing rubber structure 14 Groove

[0050] 15 Opening of the rubber structure Detailed implementation manners

[0051] As Figure 1 shown, the battery diaphragm test device 1 of the present invention includes pipelines, a thermocouple 6, a temperature monitoring device 7, a flow monitoring device 8, a gas cylinder, a fixture, a pneumatic valve, etc. The pipeline is divided into two sections. The diaphragm sample 5 is fixed between the two sections of pipelines through the fixture. The two ends of the pipelines are hermetically connected into one body through the sealing rubber structure 13 on the fixture. The open end on one side of the pipeline is the fluid inlet 2, which is connected to the gas cylinder through a gas pipe. The open end on the other side of the pipeline is the first fluid outlet 3; a second fluid outlet 4 is arranged on the side surface of the pipeline at the fluid inlet 2 end; the diaphragm sample 5 forms a closed surface in the pipeline between the second fluid outlet 4 and the first fluid outlet 3, and the closed surface formed by the diaphragm sample 5 is perpendicular to the extension direction of the pipeline; the thermocouple 6 is arranged at one end of the diaphragm sample 5, the thermocouple 6 is in contact with the fixture and is connected to the temperature monitoring device 7 through a wire to transmit the temperature signal to the temperature monitoring device for detecting the temperature of the diaphragm sample; the flow monitoring device 8 is respectively installed at one end of the fluid inlet 2 close to the diaphragm sample 5 and one end of the first fluid outlet 3, and the flow monitoring device 8 is a flow sensor or other device; the second fluid outlet 4 is connected to a gas pipe and a valve, and the fluid flow discharged from the second fluid outlet 4 is controlled by the valve to ensure that the fluid volume passing through the surface of the diaphragm sample 5 always remains at V0. The cross-section of the pipeline is square or may also be rectangular.

[0052] The diaphragm clamp includes upper and lower clamping plates and movable bolts. The upper and lower clamping plates of the clamp have the same structure. The diaphragm sample 5 is placed between the upper and lower clamping plates and fixed by tightening the movable bolts. The rubber sealing structure 13 on the surface of the clamping plates plays a sealing role. The upper and lower clamping plates are buckled with each other to form a square or rectangular frame structure, whose shape is the same as the cross-section of the pipeline and the size is matched with the inner diameter size of the pipeline.

[0053] As Figure 2-1 and Figure 2-2 shown, the structure of the upper or lower clamping plate 9 of the diaphragm clamp of the present invention includes a metal body 10 and a sealing rubber structure 13. The sealing rubber structure 13 is sleeved on the metal body 10. The metal body 10 of the clamp includes a test frame and connecting parts connected to both sides of the test frame. A first metal body opening 11 is provided on the test frame, and a second metal body opening 12 is provided on the connecting part. The first metal body opening 11 is a diaphragm test hole, which can communicate with the first fluid outlet 3 and the second fluid outlet 4 during the test process, and its size is matched with the pipeline size. The second metal body opening 12 is matched with the movable bolt and is used to fix the diaphragm. The sealing rubber structure 13 includes a groove 14 and a rubber structure opening 15. As Figure 2-1 shown, a groove is provided on the A-side sealing rubber structure 13 of the upper or lower clamping plate 9 of the diaphragm clamp, and the groove is annular; the groove 14 serves as the positioner for the first fluid outlet 3 and the second fluid outlet 4 during the feeding of the clamp, so as to ensure the sealing performance during the test process. A rubber structure opening 15 is provided in the middle of the sealing rubber structure 13, and the size of the rubber structure opening 15 is matched with that of the first metal body opening 11. The sealing rubber structure 13 is sleeved on the test frame of the metal body 10. As Figure 2-2 shown, there is no groove 14 on the B-side sealing rubber structure 13 of the upper or lower clamping plate 9 of the diaphragm clamp, and the rest of the structure is exactly the same as that of the A side.

[0054] During the diaphragm feeding process, the B side of the structures of the upper and lower clamping plates of the diaphragm clamp is adjacent to the diaphragm sample 5, and the A side of the upper and lower clamping plates of the diaphragm clamp is adjacent to the first fluid outlet 3 and the second fluid outlet 4. The rubber sealing structure 13 on the surface of the diaphragm clamp plays a sealing role. The pneumatic valve is connected to the pipeline and can control the left and right movement of the pipeline. The gas inlet and outlet pipeline is controlled by the pneumatic valve to move left and right, so that the two sections of the pipeline are respectively moved to both sides of the clamp, pressed and sealed, or moved away from both sides of the clamp to facilitate the feeding and taking of the diaphragm clamp.

[0055] When using the above device to detect the performance of the lithium-ion battery diaphragm, the specific implementation steps are as follows:

[0056] (1) Cut out a PP diaphragm sample 5 with appropriate size and fix the sample in the pipeline;

[0057] (2) Control the fluid inlet flow rate to a fixed value V0 through the flow monitoring device 8, where V0 = 5 ml / s;

[0058] (3) Place the pipeline in a heating device, such as an oven, and heat it up to 300 degrees Celsius at a rate of 5 °C per minute;

[0059] (4) The flow monitoring device 8, the temperature monitoring device 7 and the thermocouple 6 monitor and record the flow rate and the body surface temperature of the diaphragm in real time. When the diaphragm closes or breaks, the fluid inlet flow rate will change. It can be controlled by adjusting Figure 1 the flow rate of the second fluid outlet in to control the amount of fluid passing through the left surface of the diaphragm, so that it always remains at V0, and record Figure 1 the flow rate V1 of the first fluid outlet in;

[0060] (5) According to the process data, plot the curve of temperature - fluid outlet flow percentage (V1 / V0 * 100%) (i.e., the amount of fluid passing through the diaphragm), as shown in Figure 3 ;

[0061] (6) According to the Figure 3 curve of temperature - fluid outlet flow percentage change, take the temperatures corresponding to the points where the fluid outlet flow rate suddenly drops and suddenly rises as the initial closing temperature and the initial breaking temperature of the diaphragm sample 5. The initial closing temperature and the initial breaking temperature of the diaphragm sample 5 are T0 and T4 respectively; take the number of steps of the fluid outlet flow rate drop in the curve as the closing temperatures and the temperature distribution of different pore sizes. Please describe the closing temperatures and the temperature distribution of different pore sizes; it can be seen from the curve that there are two dropping steps, indicating that there are two regions with concentrated pore sizes in the diaphragm. Among them, the closing temperature of the smaller pore size is in the range of T0 - T1, and the closing temperature of the larger pore size is in the range of T2 - T3. The slope of the curve in the T0 - T1 region is larger, which can to a certain extent indicate that the pore size distribution is wider at the smaller pore size of the diaphragm; the slope of the curve in the T2 - T3 region is smaller, indicating that the pore size distribution is concentrated at the larger pore size of the diaphragm. H0 - H1 and H2 - H3 can represent the proportions of the smaller pore size and the larger pore size in the diaphragm, which are (H0 - H1) * 100% / (H0 - H1 + H2 - H3) or (H0 - H1) * 100% / (H0 - H3); (H2 - H3) * 100% / (H0 - H1 + H2 - H3) or (H2 - H3) * 100% / (H0 - H3).

[0062] (7) Repeat the above steps (1) - (6) at least three times, and take the average value of the initial closing temperature and the initial breaking temperature measured each time as the closing temperature and the breaking temperature of the diaphragm, to obtain the average initial closing temperature and the average initial breaking temperature of the diaphragm sample 5 (T01 + T02 + T03 + … + T0 n ) / n, (T41 + T42 + T43 + … + T4 n ) / n, and the performance test results are shown in Table 1.

[0063] Table 1 PP diaphragm performance test results

[0064]

[0065] Note: The values in the test data are all the average values of 5 measurements. The existing method 1 uses the resistance method, and the value is taken at the resistance mutation point. The existing method 2 uses TG thermal analysis, and the temperature at the peak is taken.

[0066] The present invention provides a simple diaphragm performance test method and device, which can accurately and effectively analyze the closed pore temperature, film rupture temperature of the diaphragm body, and the distribution of closed pores and film rupture with different pore diameters during the process. The fluid used in this method can be air, or nitrogen or any other non-toxic, harmless and safe gas. A thermocouple can be used to measure and monitor the temperature of the diaphragm body during the process, and other temperature acquisition methods can also be used. According to the pressure resistance of the diaphragm, the inlet flow rate of the fluid during the process can be adjusted to avoid the influence of high pressure on the test results. The fluid inlet and outlet structure can be in any form. This method adjusts the flow rate on one side of the diaphragm by increasing the fluid outlet 2, and also includes other methods that can adjust the flow rate stability.

[0067] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the above embodiments have described the present invention in detail, those skilled in the relevant art should understand that any equivalent transformation made by using the content of the specification of the present invention, or any modification and replacement directly or indirectly applied in the relevant technical field without departing from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for detecting the performance of a battery separator, comprising the following steps: (1) Cut out a separator sample of appropriate size and fix the separator sample in a pipeline to form a closed surface in the middle of the pipeline between the second fluid outlet and the first fluid outlet; one end of the pipeline is a fluid inlet, the other end is the first fluid outlet, and a second fluid outlet is provided on the side of the pipeline at the fluid inlet end; (2) Control the fluid inlet flow rate to a fixed value V0 through a flow monitoring device; (3) Place the pipeline in a heating device and heat it up to 300 °C at a certain speed; (4) The flow monitoring device, temperature monitoring device and thermocouple monitor and record the flow rate and the surface temperature of the separator in real time. When the separator closes pores or breaks, adjust the flow rate of the second fluid outlet to control the fluid volume passing through the separator surface so that it always remains V0, and record the flow rate V1 of the first fluid outlet at the same time; (5) According to the process data, plot the temperature-fluid outlet flow percentage curve H = V1 / V0 * 100%; (6) According to the temperature-fluid outlet flow percentage change curve, take the temperatures corresponding to the points where the fluid outlet flow rate suddenly drops and suddenly rises as the initial pore closing temperature and initial film breaking temperature of the separator sample; take the number of steps of the fluid outlet flow rate drop in the curve as the pore closing temperature and temperature distribution of different pore sizes; (7) Repeat the above steps (1)-(6) at least three times, and take the average value of the measured initial pore closing temperature and initial film breaking temperature as the pore closing temperature and film breaking temperature of the separator.

2. The detection method for the performance of the battery separator according to claim 1, characterized in that: The fluid used in the method is air or nitrogen; the fluid inlet flow rate is adjusted according to the pressure resistance of the separator.

3. The detection method for the performance of the battery separator according to claim 1, characterized in that: The heating device is an oven; the heating rate is 3-5 °C per minute.

4. A detection device for the performance of a battery separator, characterized in that: It includes a pipeline, a thermocouple, a temperature monitoring device, a flow monitoring device, a gas cylinder, a fixture and a pneumatic valve. The pipeline is divided into two sections. The diaphragm sample is fixed between the two sections of the pipeline by the fixture, and the two ends of the pipeline are hermetically connected into one body through the fixture. The open end on one side of the pipeline is the fluid inlet, which is connected to the gas cylinder through a gas pipe. The open end on the other side of the pipeline is the first fluid outlet; a second fluid outlet is provided on the side surface of the pipeline at the fluid inlet end; the diaphragm sample forms a closed surface in the pipeline between the second fluid outlet and the first fluid outlet; the thermocouple is arranged at one end of the diaphragm sample and is connected to the temperature monitoring device through a wire; the flow monitoring devices are respectively installed between the second fluid outlet and the diaphragm sample and at the first fluid outlet; the fixture includes upper and lower clamping plates and movable bolts, and the upper and lower clamping plates have the same structure; the upper clamping plate or the lower clamping plate of the fixture includes a metal main body and a sealing rubber structure, and the sealing rubber structure is sleeved on the metal main body; the diaphragm sample is placed between the upper and lower clamping plates and is fixed by tightening the movable bolts, and the rubber sealing structure on the surface of the clamping plate plays a sealing role; the metal main body includes a test frame and connecting parts connected to both sides of the test frame, a first opening of the metal main body is provided on the test frame, and a second opening of the metal main body is provided on the connecting part; the first opening of the metal main body is a diaphragm test hole, and its size matches that of the pipeline, and the second opening of the metal main body matches the movable bolt; the sealing rubber structure includes a groove and an opening of the rubber structure; a groove is provided on one side of the sealing rubber structure, and the other structures on both sides are exactly the same; an opening of the rubber structure is provided in the middle of the sealing rubber structure, and the sealing rubber structure is sleeved on the test frame of the metal main body; the thermocouple contacts the fixture and transmits the temperature signal to the temperature monitoring device; the flow monitoring device is a flow sensor; the pneumatic valve is connected to the pipeline to control the left and right movement of the pipeline for feeding and taking the diaphragm fixture.

5. The detection device for the performance of the battery separator according to claim 4, wherein: The second fluid outlet is connected to a gas pipe and a valve, and the flow rate of the fluid discharged from the second fluid outlet is controlled by the valve so that the amount of fluid passing through the surface of the diaphragm sample always remains the same as the fluid inlet flow rate.

6. The detection device for the performance of the battery separator according to claim 4, characterized in that: The cross-section of the pipeline is square or rectangular.

Images