CN219641509U - Diaphragm wetting rate testing arrangement - Google Patents

Abstract

The utility model relates to a diaphragm wetting rate testing device, comprising a bottom plate (9), a scale (2), a test box body (4), a right support platform (6), a diaphragm to be tested (8), a fixed pulley (11 ) and a torque motor (12), the left and right sides of the test box body (4) are respectively provided with a diaphragm left retainer (1) and a diaphragm right retainer (5), and the diaphragm left retainer (1) and diaphragm right retainer A drop limiter (3) is provided between the fixers (5), and a liquid feeding device (7) is provided on the drop limiter (3), and the scale (2) is connected to the diaphragm to be measured ( 8) Parallel, the right side of the diaphragm right fixer (5) is provided with a traction rope (10). The utility model can avoid wrinkling and bending of the diaphragm to be tested, and ensure that the tensile force and elastic deformation of the diaphragm are consistent during different tests, thereby improving the test accuracy.

Description

A diaphragm wetting rate testing device

technical field

The utility model relates to the technical field of production of energy storage devices, in particular to a diaphragm wetting rate testing device for lithium ion batteries.

Background technique

Lithium-ion batteries mainly include positive and negative electrode materials, separators, electrolytes, and housings. The separator is responsible for separating the positive and negative electrodes, while the electrolyte plays the role of transporting anions and cations. The wettability of the electrolyte to the separator and the positive and negative active materials is related to battery performance and manufacturing cost. The wettability of the separator is generally smaller than that of the positive and negative active materials. Therefore, the wettability of the electrolyte to the separator is a measure of the wettability of the electrolyte. Key indicators of capability.

Patent CN215179417U discloses a membrane wettability test device, including a test frame and a scale, the test frame is provided with a left clamping piece and a right clamping piece for clamping the left and right ends of the diaphragm to be tested, and the left clamping piece and the right clamping piece An electrolyte container for containing the electrolyte is provided below the holders, and a lifting platform for supporting the electrolyte container and a lifting drive mechanism for controlling the up and down movement of the lifting platform are provided on the test frame. The capillary tube through which the electrolyte penetrates upwards. The outer surface of the reagent bottle is provided with a liquid injection port. During the test, the left and right ends of the diaphragm to be tested are clamped between the left clamping piece and the right clamping piece, and the lower end of the capillary is immersed in the electrolyte. The upper end of the capillary is in contact with the lower surface of the membrane to be tested, and the scale is arranged transversely on one side of the membrane to be tested. The test process can make the lateral diffusion speed of the electrolyte more uniform and avoid the influence of gravity on the diffusion of the electrolyte on the diaphragm. However, the test results of this device are greatly affected by the surface tension of the electrolyte and the radius of the capillary, resulting in insufficient test accuracy.

Patent CN112858103A discloses a test device and test method for the wettability of a lithium-ion battery diaphragm. A water tank, the water tank is provided with a heater; a lifting device is provided above the water tank, and the lifting device is used to lift the object to be tested, and a monitor is also provided in the sealed housing, and the monitor is used to observe the seal condition inside the housing. This test method can realize the wettability measurement under different temperatures and pressures, but if the diaphragm curls during the test process, it will have a great impact on the test results, and the test accuracy will have a large error.

Existing test devices have complex structures, cannot guarantee the complete stretching of the diaphragm or cannot determine the tension applied to the diaphragm, and the deformation of the diaphragm is unknown, resulting in poor reproducibility of test results, large accuracy errors, and unsatisfactory test results.

Utility model content

The utility model aims at the problems existing in the prior art, and provides a diaphragm wetting rate test device, which can ensure that the diaphragm is fully stretched and the tensile force received when testing different diaphragms is basically the same, and the test results are less affected by the bending and deformation of the diaphragm, and the electrolytic The liquid spreads more evenly, the test accuracy is higher, and the effect is better.

In order to achieve the above object, the utility model adopts the following technical solutions:

A diaphragm wetting rate testing device, comprising a bottom plate (9), a scale (2), a test box (4), a right support platform (6), a diaphragm to be tested (8), a fixed pulley (11) and a torque motor (12), the left and right sides of the test box body (4) are respectively provided with a diaphragm left retainer (1) and a diaphragm right retainer (5), and the diaphragm left retainer (1) and diaphragm right retainer (5) ) is provided with a drip limiter (3), the drip limiter (3) is provided with a liquid addition device (7), and the scale (2) is parallel to the diaphragm to be measured (8), The right side of the diaphragm right fixer (5) is provided with a traction rope (10).

During the test, the left and right ends of the diaphragm to be tested (8) are respectively fixed on the diaphragm left retainer (1) and the diaphragm right retainer (5), and the diaphragm left retainer (1) and the diaphragm right retainer (5) Alignment marks are respectively provided to ensure that the two ends of the diaphragm (8) to be tested are aligned, the left diaphragm fixer (1) is fixed on the left side of the test box body (4), and the right diaphragm fixer (5) can pass through Traction rope (10) moves left and right on the test box body (4) and the right holder support platform (6) under the effect of torque motor (12).

As a preferred solution, the center positions of the left diaphragm fixer (1), the drop stopper (3), the right diaphragm fixer (5) and the fixed pulley (11) are located on the same horizontal straight line.

As a preferred solution, the left diaphragm fixer (1) and the right diaphragm fixer (5) are fixing clips.

As a preferred solution, the drip limiter (3) is used to limit the drip position, can move left and right on the test box body (4), and can perform multiple measurements on the diaphragm (8) to be tested; The liquid device (7) is a pipette gun, a liquid injector or a capillary. The height of the lower end of the liquid adding device from the diaphragm to be tested is 0.5-5mm.

As a preferred solution, the torque motor (12) controls the tension of the diaphragm to be tested (8) by adjusting the voltage, and the tension of the diaphragm to be tested is the same.

Compared with the prior art, the utility model has the following beneficial effects:

1. The utility model can ensure that the diaphragm to be tested is completely stretched and the tensile force on the diaphragm is basically the same in different tests. The test results are less affected by the bending and deformation of the diaphragm, ensuring the test accuracy and test effect;

2. Use the drop limiter to ensure that the liquid filling position and height are basically the same for each test, so that the electrolyte can spread evenly in the diaphragm, and the test accuracy is higher and the effect is better;

3. The utility model has the advantages of simple structure, reasonable setting and high testing precision, which is beneficial to popularization.

Description of drawings

Accompanying drawing 1 is the structural diagram of the membrane wetting rate testing device described in the embodiment of the present invention.

Detailed ways

The utility model will be further described below in conjunction with specific embodiments, but the utility model is not limited to these specific embodiments. It should be pointed out that those skilled in the art can make several similar deformations and improvements without departing from the inventive concept of the present invention, and these are also considered within the protection of the present invention.

As shown in Figure 1, a diaphragm wetting rate test device includes a base plate (9), a scale (2), a test box body (4), a right support platform (6), a diaphragm to be tested (8), and a fixed pulley (11) and torque motor (12), the left and right sides of described test box body (4) are respectively provided with diaphragm left retainer (1) and diaphragm right retainer (5), described diaphragm left retainer (1) and diaphragm A drip limiter (3) is arranged between the right diaphragm fixer (5), and a liquid adding device (7) is arranged on the drip limiter (3), and the scale (2) is connected to the The diaphragms (8) are parallel, and the right side of the diaphragm right fixer (5) is provided with a traction rope (10).

During the test, the left and right ends of the diaphragm to be tested (8) are respectively fixed on the diaphragm left retainer (1) and the diaphragm right retainer (5), and the diaphragm left retainer (1) and the diaphragm right retainer (5) Alignment marks are respectively provided to ensure that the two ends of the diaphragm (8) to be tested are aligned, the left diaphragm fixer (1) is fixed on the left side of the test box body (4), and the right diaphragm fixer (5) can pass through Traction rope (10) moves left and right on the test box body (4) and the right holder support platform (6) under the effect of torque motor (12). The central positions of the left diaphragm fixer (1), the drop stopper (3), the right diaphragm fixer (5) and the fixed pulley (11) are located on the same horizontal straight line.

The torque motor (12) of the utility model controls the pulling force of the diaphragm to be tested (8) by adjusting the voltage, so that the pulling force of the diaphragm to be tested is the same. Specifically, during each measurement, the tension of the diaphragm to be tested is guaranteed to be The value of the force coefficient k is the same, so that the deformation of the test diaphragm is guaranteed to be consistent.

Diaphragm force coefficient k value calculation method: according to the formula Calculate the force coefficient k value of the diaphragm;

k: diaphragm force coefficient per unit area; F: pull force provided by the torque motor, N;

X: the distance between the left diaphragm holder and the right diaphragm holder, mm; d: the width of the diaphragm to be tested, mm.

A method for testing the wettability of a diaphragm by adopting the utility model, specifically comprising the following steps:

A1. First use the diaphragm left retainer (1) and diaphragm right retainer (5) to fix the left and right ends of the diaphragm to be tested (8), turn on the torque motor (12), and pull the diaphragm right retainer ( 5) Move to the right and control the pulling force F to cause a certain elastic deformation of the diaphragm (8) to be tested until the diaphragm (8) to be tested is completely stretched;

A2. Add the electrolyte dropwise to the surface of the diaphragm to be tested (8) through the liquid feeding device (7) on the drop stopper (3), and record the diffusion of the electrolyte on the diaphragm within a unit time t after the drop of the electrolyte distance;

A3. Wetting rate determination: by formula Calculate the wetting rate V of the electrolyte solution to be measured diaphragm (8);

t: diffusion time of the electrolyte on the diaphragm, s; L: maximum diffusion diameter of the electrolyte on the diaphragm, mm; d: width of the diaphragm to be tested, mm.

The greater the wetting rate V of the diaphragm (8) to be tested, the better the wettability of the electrolyte to the diaphragm (8) to be tested, and vice versa.

Example 1

(1) Basic electrolyte configuration: In a glove box filled with argon (moisture content <5ppm, oxygen content <10ppm), ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are prepared by mass ratio as EC:EMC= Mix evenly at 3:7, slowly add lithium hexafluorophosphate (LiPF ₆ ) into the mixed solution until the molar concentration of LiPF ₆ is 1.0 mol/L, and obtain basic electrolyte 1.

(2) Determination of diaphragm wetting rate:

A1. Fix the diaphragms with a width of 3 mm and a length of about 200 mm on the left and right diaphragm holders of the test device respectively, start the torque motor, and adjust the output tension so that the force coefficient k of the diaphragm is 0.02N/mm ² ;

A2. Use a pipette gun to drop 30uL of the above-mentioned basic electrolyte 1 onto the diaphragm through the liquid adding device, and record the diffusion distance L of the electrolyte on the diaphragm after 20s;

A3. Determination of wetting rate: Calculate the wetting rate V of the electrolyte to the diaphragm, and record the test result as 1, as shown in Table 1;

Move the drip stopper 80mm to the left, repeat the operations of A2 and A3, and record the test result as 2, as shown in Table 1;

Replace the diaphragm, repeat operations A1 to A3, and record the test result as 3, as shown in Table 1.

Example 2

(1) Basic electrolyte configuration: the operation is the same as in Example 1, the difference is only that ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are uniformly mixed according to the mass ratio of EC:EMC=3:7, and the other operations are not Change to obtain the basic electrolyte 2.

(2) Determination of membrane wetting rate: the operation is the same as in Example 1, and the test result is recorded as 4, specifically as shown in Table 1;

Move the drop stopper 80mm to the left, repeat the A2 and A3 operations of embodiment 1, and the test result is recorded as 5, specifically as shown in table 1;

The diaphragm was replaced, and the operations A1 to A3 of Example 1 were repeated, and the test result was recorded as 6, as shown in Table 1.

The membranes tested in Example 1 and Example 2 are the same batch of membranes.

The test result of table 1 embodiment 1 and embodiment 2

By testing the wettability of electrolytes in two different solvent systems to the separator, it can be found that the wetting effect of EC/EMC/DMC=2/1/7 is significantly better than that of EC/EMC=3/7; the same electrolyte sample is repeated After the test, the test results have good reproducibility and high test accuracy.

To sum up, the utility model fixes the diaphragm to be tested by the left and right holders of the diaphragm, and uses the torque motor to pull the right holder to move, so that the diaphragm to be tested is evenly stressed and undergoes a certain elastic deformation, so that the diaphragm to be tested is completely stretched out. , by controlling the voltage of the torque motor to ensure that the tension of different test diaphragms is the same, it can ensure that the diaphragm to be tested is completely stretched and the tension of the diaphragm is basically the same in different tests, the test results are less affected by the bending and deformation of the diaphragm, and the test accuracy is guaranteed And the test effect; moreover, the height and position of the dripping liquid are controlled by the drip limiter to ensure that the position and height of the liquid addition are basically the same in each test, so that the electrolyte can spread evenly in the diaphragm, thus effectively avoiding the liquid addition The influence of factors such as height and location on the test accuracy. In addition, the utility model has the advantages of simple structure, reasonable setting and high testing precision, which is beneficial to popularization.

Claims (7)

1. A device for testing the wetting rate of a diaphragm, characterized by: the diaphragm wetting rate testing device comprises a bottom plate (9), a graduated scale (2), a testing box body (4), a right supporting table (6), a diaphragm (8) to be tested, a fixed pulley (11) and a torque motor (12), wherein a diaphragm left fixer (1) and a diaphragm right fixer (5) are respectively arranged on the left side and the right side of the testing box body (4), a liquid dropping limiter (3) is arranged between the diaphragm left fixer (1) and the diaphragm right fixer (5), a liquid adding device (7) is arranged on the liquid dropping limiter (3), the graduated scale (2) is parallel to the diaphragm (8) to be tested, and a traction rope (10) is arranged on the right side of the diaphragm right fixer (5).

2. The separator wetting rate testing device according to claim 1, wherein: during testing, the left end and the right end of the diaphragm (8) to be tested are respectively fixed on the left diaphragm fixer (1) and the right diaphragm fixer (5), and the left diaphragm fixer (1) and the right diaphragm fixer (5) are respectively provided with alignment marks for guaranteeing alignment of the two ends of the diaphragm (8) to be tested, the left diaphragm fixer (1) is fixed on the left side of the test box body (4), and the right diaphragm fixer (5) can move left and right on the test box body (4) and the right fixer supporting table (6) under the action of the torque motor (12) through the traction rope (10).

3. The separator wetting rate testing device according to claim 2, wherein: the left diaphragm fixer (1) and the right diaphragm fixer (5) are fixing clamps.

4. The separator wetting rate testing device according to claim 1, wherein: the liquid adding device (7) is a liquid transferring gun, a liquid injector or a capillary tube.

5. The separator wetting rate testing device according to claim 1, wherein: the height of the lower end of the liquid adding device from the diaphragm to be measured is 0.5-5 mm.

6. The separator wetting rate testing device according to claim 1, wherein: the center positions of the left diaphragm fixer (1), the drip limiter (3), the right diaphragm fixer (5) and the fixed pulley (11) are positioned on the same horizontal straight line.

7. The separator wetting rate testing device according to claim 1, wherein: the torque motor (12) adjusts the tensile force of the diaphragm (8) to be tested through voltage, so that the tensile force of the diaphragm to be tested is the same.