CN211825790U

CN211825790U - Testing device for testing thermal closed hole temperature and film breaking temperature of lithium battery diaphragm in batch

Info

Publication number: CN211825790U
Application number: CN201922072177.3U
Authority: CN
Inventors: 程跃; 匡吴奇; 庄志; 鲍晋珍
Original assignee: Wuxi Enjie New Material Technology Co ltd
Current assignee: Wuxi Enjie New Material Technology Co ltd
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2020-10-30
Anticipated expiration: 2029-11-27

Abstract

The utility model relates to a test device for batch testing of the thermal closed hole temperature and the film breaking temperature of lithium battery diaphragms, wherein the test die comprises a CR2016 button battery, a T-shaped thermocouple and a polytetrafluoroethylene nut; go up screw terminal and screw terminal down and pass through the electric welding and connect on the nut of last screw and screw down, go up the screw and screw precession polytetrafluoroethylene nut down through the screw thread, polytetrafluoroethylene nut center department opens has the aperture, passes the aperture with T type thermocouple, fixes in the recess of screw down, and CR2016 button cell's negative pole face down screw side is placed in polytetrafluoroethylene nut, places the spring in polytetrafluoroethylene nut, makes it and button cell present free contact state. This application is through connecting a plurality of test mould on multichannel data acquisition appearance, and the development and the production of diaphragm product can effectively be instructed to the hot hole temperature of closing and the rupture of membranes temperature of big batch, quick, accurate test diaphragm.

Description

Testing device for testing thermal closed hole temperature and film breaking temperature of lithium battery diaphragm in batch

Technical Field

The utility model belongs to the technical field of diaphragm test equipment technique and specifically relates to a test device of test lithium cell diaphragm heat shut hole temperature and rupture of membranes temperature in batches.

Background

With the development of science and technology, lithium ion batteries have been widely applied to 3C electronic devices and power automobiles, which rapidly drives the production of diaphragms, which are important constituent materials of lithium ion batteries. However, in recent years, the safety accidents of the lithium battery are frequent, which causes a great amount of property loss and even threatens the personal safety, so that the improvement of the safety performance of the lithium battery in all aspects is not slow to the development of the whole industry, and the diaphragm serving as one of four core materials in the lithium battery is of great importance to the safety performance of the lithium battery.

As is well known, the separator has the function of separating the positive electrode and the negative electrode of the battery to prevent the contact between the positive electrode and the negative electrode from causing safety problems, and the microporous structure of the separator can allow electrolyte ions to pass through. The performance directly determines the interface structure, internal resistance and heat resistance of the battery, and further directly influences the electrical performance and safety performance of the battery. When the diaphragm reaches a certain temperature, the internal micropores of the diaphragm are closed to a certain degree, so that the flow channel of lithium ions is cut off, the temperature of the battery is prevented from rising continuously, and the safety of the lithium ion battery is guaranteed; if the temperature continues to rise, the membrane can be fused, so that the whole membrane is broken, the effect of isolating the positive electrode and the negative electrode disappears, and the lithium ion battery is easy to lose control. Therefore, the two critical temperatures have very important influence on the safety performance of the lithium ion battery, and how to test the thermal closed pore temperature and the membrane breaking temperature of the diaphragm quickly, accurately and in batch is a continuously pursued target in the whole industry.

At present, the thermal pore-closing temperature and the rupture temperature of the diaphragm also have partial testing methods, including a method for testing the change of the internal resistance value of the diaphragm along with the temperature and a method for testing the change of the gas throughput of the diaphragm along with the temperature, however, the methods are all faced with a method with single testing times, if the diaphragm is required to be tested simultaneously in a large batch, additional testing equipment is required, and the cost is increased. In order to solve the difficulty of rapidly, accurately and massively testing the thermal closed pore temperature of the diaphragm of the lithium ion battery required in the diaphragm industry, the invention develops a testing device for testing the thermal closed pore temperature and the rupture temperature of the diaphragm of the lithium ion battery in batches.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's is not enough, provides a test device of test lithium cell diaphragm heat shut hole temperature and rupture of membranes temperature in batches.

The purpose of the utility model is realized through the following technical scheme:

a test device for batch testing of the thermal closed hole temperature and the membrane breaking temperature of a lithium battery diaphragm comprises a CR2016 button battery, a T-shaped thermocouple and a polytetrafluoroethylene nut; go up screw terminal and screw terminal down and pass through the electric welding and connect on the nut of last screw and screw down, go up the screw and screw precession polytetrafluoroethylene nut down through the screw thread, polytetrafluoroethylene nut center department opens has the aperture, passes the aperture with T type thermocouple, fixes in the recess of screw down, and CR2016 button cell's negative pole face down screw side is placed in polytetrafluoroethylene nut, places the spring in polytetrafluoroethylene nut, makes it and button cell present free contact state.

The button cell needs to be packaged, the diaphragm sample wafer is assembled according to the assembly sequence of the positive electrode shell, the first stainless steel gasket, the diaphragm, the second stainless steel gasket, the elastic sheet and the negative electrode shell, the diaphragm is packaged into the CR2016 type button cell through a button cell sealing machine, and the packaging pressure of the button cell is 1000 PSI.

The temperature measuring range of the T-shaped thermocouple is 0-350 ℃, and the temperature precision is 0.5 ℃.

And connecting a plurality of test dies on test equipment in parallel, and testing the thermal closed hole temperature and the rupture temperature of the diaphragm in batches.

And 5 test dies are connected in parallel on the test equipment.

The test equipment comprises five test dies, a lead, a temperature data acquisition module, a resistance data acquisition module and a multi-channel data acquisition instrument; the upper and lower screw binding posts of the 5 testing dies are respectively connected to the resistance data testing module through leads, the thermocouples of the dies are connected to the temperature data testing module through leads, and the resistance data acquisition module and the temperature data acquisition module are welded on the multi-channel data acquisition instrument.

Compared with the prior art, the utility model has the positive effects that:

by designing a convenient and practical test die, the packaged button cell is placed in the die, and the obtained data is accurate, stable and reliable; and a plurality of testing dies can be connected on the multi-channel data acquisition instrument to test the hot closed hole temperature and the film breaking temperature of the diaphragm in batches, so that the testing efficiency of the hot closed hole temperature and the film breaking temperature of the diaphragm is greatly improved.

Drawings

FIG. 1 is a block diagram of a test fixture according to the present application;

FIG. 2 is a top view of an upper screw in a test mold of the present application;

FIG. 3 is a top view of a Teflon nut in the test fixture of the present application;

FIG. 4 is a top view of a lower screw and a lower screw recess in a test mold of the present application;

FIG. 5 is a connection diagram of the test equipment of the present application;

the labels in the figures are:

1, a screw binding post is arranged on the screw,

2, the screw is arranged on the screw rod,

3, a polytetrafluoroethylene nut is arranged on the outer side of the nut,

4, a spring is arranged in the groove,

a 5CR2016 type button cell battery,

a type 6T thermocouple is arranged on the base,

7 a lower screw is arranged on the lower part of the screw,

8, a lower screw wiring terminal is arranged on the lower screw,

9 a first test mould to be tested is provided,

10 a second test mould to be tested,

11 a third test mould to be tested,

12 a first conductive line of a first type,

13 a fourth test mould to be used in the method,

14 a fifth test mold, the test mold,

15 a second conductive line(s) formed on the first conductive line,

16 a temperature data acquisition module for acquiring the temperature data,

17 a resistance data acquisition module for acquiring the resistance data,

18 a multichannel data acquisition instrument;

FIG. 6 is a flow chart of a test method of the present application.

Detailed Description

The following provides the utility model relates to a test device's of batch test lithium cell diaphragm hot closed pore temperature and rupture of membranes temperature concrete implementation mode.

Example 1

Referring to the attached drawings 1-5, a test device for batch testing of the thermal closed hole temperature and the membrane rupture temperature of a lithium battery diaphragm comprises a CR2016 button battery 5, a T-shaped thermocouple 6 and a polytetrafluoroethylene nut 3; go up screw terminal 1 and screw terminal 8 down and through the electric welding connection on the nut of last screw 2 and screw 7 down, go up screw 2 and screw 7 down and screw precession polytetrafluoroethylene nut 3 through the screw thread, polytetrafluoroethylene nut center department opens has aperture 3, pass T type thermocouple 6 aperture, fix in the recess 11 of screw down, CR2016 button cell 5's negative pole face down screw side is placed in polytetrafluoroethylene nut, place spring 4 in polytetrafluoroethylene nut, make it present free contact state with button cell.

The button cell 5 needs to be packaged, the diaphragm sample sheet is assembled according to the assembly sequence of the positive electrode shell, the first stainless steel gasket, the diaphragm, the second stainless steel gasket, the elastic sheet and the negative electrode shell, the diaphragm is packaged into a CR2016 type button cell through a button cell sealing machine, and the packaging pressure of the button cell is 1000 PSI.

The temperature measuring range of the T-shaped thermocouple 6 is 0-350 ℃, and the temperature precision is 0.5 ℃.

And connecting 5 test dies on the test equipment in parallel, and testing the hot closed hole temperature and the membrane rupture temperature of the diaphragm in batches.

The test equipment comprises a first test die 9, a second test die 10, a third test die 11, a fourth test die 13, a fifth test die 14, a first lead 12, a second lead 15, a temperature data acquisition module 16, a resistance data acquisition module 17 and a multi-channel data acquisition instrument 18; the upper and lower screw terminals of the first test mould 9, the second test mould 10, the third test mould 11, the fourth test mould 13 and the fifth test mould 14 are connected to the resistance data test module 13 through the first lead 12, the thermocouple of the mould is connected to the temperature data acquisition module 17 through the second lead 15, and the resistance data acquisition module 16 and the temperature data acquisition module 17 are welded on the multi-channel data acquisition instrument 18.

The flow chart of the test method of the application is shown in FIG. 6:

the test method comprises the following specific steps:

1) firstly, the testing method needs to use a die cutter to cut the diaphragm into a circular sample piece with the thickness of 15.8mm, and soak the sample piece in 10mL of electrolyte for 2h to enable the diaphragm to be fully soaked.

2) And then assembling the diaphragm sample wafer according to the assembly sequence of the positive electrode shell, the first stainless steel gasket, the diaphragm, the second stainless steel gasket, the elastic sheet and the negative electrode shell, and packaging the diaphragm sample wafer into the CR2016 type button battery by using a button battery sealing machine, wherein the packaging pressure is 1000 PSI.

3) And placing the packaged button battery with the negative electrode surface facing downwards into a testing mold, placing a spring on the button battery, screwing the upper screw into the testing mold, enabling the spring to apply certain pressure to the battery, and ensuring the stable connection of the whole testing mold.

4) And simultaneously assembling 5 batches of test dies, and respectively connecting an upper screw wiring terminal, a lower screw wiring terminal and a thermocouple of the test dies to a resistance acquisition module connecting line and a temperature acquisition module connecting line of the multichannel data acquisition instrument so as to acquire internal resistance and temperature data of the diaphragm.

5) And (3) putting the whole testing mold into an oven for heating, and simultaneously, starting to record the resistance and temperature data of the diaphragm by the multi-channel data acquisition instrument.

6) The resistance value of the diaphragm can also be increased and then decreased along with the temperature rise, and when the temperature of the diaphragm reaches 180 ℃, the oven stops heating, and the test mold is removed.

7) Making a curve of the resistance data and the temperature data of the diaphragm, deriving the curve, and taking the maximum value of the derivative of the whole curve as the thermal closed hole temperature of the diaphragm, wherein the value means the point at which the resistance value of the diaphragm increases fastest along with the temperature, namely the temperature at which the diaphragm starts to close the hole; the minimum value of the derivative of the whole curve is taken as the film breaking temperature of the diaphragm, and the meaning of the value is the point at which the resistance of the diaphragm is reduced fastest along with the temperature, namely the temperature at which the diaphragm starts to break the film.

The test method takes five groups of data as a reliability judgment basis, if the temperature range of the five groups of data tested at the same time is within 1 ℃, the test result data can be considered to be reliable, and the average value of the five groups of test data is taken as the diaphragm thermal-closing hole temperature and the diaphragm rupture temperature.

Table 1: the hot closed pore temperature and the rupture temperature of a certain polyethylene-based wet diaphragm and a ceramic coating film are obtained by one-time measurement through the test method;

TABLE 1

According to the testing method, the temperature range of the testing data is basically within 1 ℃ in the same test, and the standard deviation 3 value of the diaphragm closed pore temperature and the diaphragm rupture temperature is also within 1, which shows that the testing method is accurate, stable and reliable.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the concept of the present invention, and these improvements and decorations should also be considered as within the protection scope of the present invention.

Claims

1. A test device for batch test of the thermal closed hole temperature and the film breaking temperature of a lithium battery diaphragm is characterized in that a test die comprises a CR2016 button battery, a T-shaped thermocouple and a polytetrafluoroethylene nut; go up screw terminal and screw terminal down and pass through the electric welding and connect on the nut of last screw and screw down, go up the screw and screw precession polytetrafluoroethylene nut down through the screw thread, polytetrafluoroethylene nut center department opens has the aperture, passes the aperture with T type thermocouple, fixes in the recess of screw down, and CR2016 button cell's negative pole face down screw side is placed in polytetrafluoroethylene nut, places the spring in polytetrafluoroethylene nut, makes it and button cell present free contact state.

2. The apparatus of claim 1, wherein the CR2016 coin cell is packaged by assembling a sample piece of the diaphragm according to the assembly sequence of the positive casing, the first stainless steel gasket, the diaphragm, the second stainless steel gasket, the spring plate and the negative casing, and packaging the diaphragm into the CR2016 coin cell by a coin cell sealing machine with a packaging pressure of 1000 PSI.

3. The apparatus as claimed in claim 1, wherein the T-type thermocouple has a temperature measuring range of 0-350 ℃ and a temperature accuracy of 0.5 ℃.

4. The apparatus for batch testing of thermal shutdown temperature and rupture temperature of lithium battery separator as claimed in claim 1, wherein a plurality of said test dies are connected in parallel to a test device for batch testing of thermal shutdown temperature and rupture temperature of separator.