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CN-121994635-A - Device and method for testing swelling rate of adhesive

CN121994635ACN 121994635 ACN121994635 ACN 121994635ACN-121994635-A

Abstract

The application belongs to the technical field of lithium ion battery testing, and particularly relates to a device and a method for testing the swelling rate of an adhesive. Including glass cover (1), filter bag (2), lift hack lever (3), couple (6), tension sensor (7), swelling room (8) and weighing platform (9), the swelling room sets up weighing bench is used for holding electrolyte, the couple sets up on the lift frame, the lift frame passes through the internal connection hack lever structure and realizes going up and down, link to each other with tension sensor (7) and filter bag (2) in proper order through the rope below the couple, filter bag (2) can hold the object and make the electrolyte pass through, glass cover (1) adopts the glass material for the cover is outside whole testing arrangement. The device provided by the application is used for testing the swelling rate of the adhesive, can determine the swelling saturation state of the adhesive sample in real time, can replace electrolyte in a swelling chamber, and is simple and convenient in principle and equipment.

Inventors

  • DENG JUNYU
  • LIU YUTING
  • GENG KEYI
  • XU TAO
  • ZHANG TINGXU
  • ZHANG RUI

Assignees

  • 中汽新能电池科技有限公司

Dates

Publication Date
20260508
Application Date
20260129

Claims (10)

  1. 1. The utility model provides a binder swelling rate testing arrangement, its characterized in that includes glass cover (1), filter bag (2), lifting frame pole (3), couple (6), tension sensor (7), swelling room (8) and weighing platform (9), the swelling room sets up weighing bench is used for holding electrolyte, the couple sets up on the lifting frame, the lifting frame realizes going up and down through internal connection hack lever structure, link to each other with tension sensor (7) and filter bag (2) in proper order through the rope below the couple, filter bag (2) can hold the object and make the electrolyte pass through, glass cover (1) adopts the glass material for the cover is outside whole testing arrangement.
  2. 2. The adhesive swelling ratio testing device according to claim 1, further comprising a weight indication panel (10), a function button (5) and a tension sensor indication panel (4) below the weighing table.
  3. 3. A testing method using the adhesive swelling ratio testing device according to any one of claims 1 to 2, comprising the steps of: s1, placing a swelling chamber (8) on a weighing table (9), peeling, pouring electrolyte with a fixed volume, weighing and reading the electrolyte mass of a weighing display panel (10) to be m 0 , and calculating to obtain electrolyte density rho 0 ; S2, manufacturing an adhesive sample by using a tablet press die, enabling the density rho 1 ＞ρ 0 of the pressed adhesive sample to be the same, calculating the minimum mass m 1 of the adhesive sample, and calculating the volume V 1 by using a cylindrical volume formula; S3, driving the lifting frame rod (3) to descend so that the filter bag (2) is completely immersed in electrolyte, and reading the mass indication m 2 by the weighing table (9); S4, placing the adhesive sample in the filter bag (2), completely immersing the adhesive sample in electrolyte in the swelling chamber (8), covering the filter bag with the glass cover (1) to reduce environmental interference, and reading the mass indication m 3 through the weighing table (9) when the adhesive sample reaches a swelling saturated state; S5, taking out the electrolyte liquid level of the filter bag (2) filled with the adhesive sample, when the adhesive sample is dried, and the indication number of the tension sensor is stable and unchanged within 10min, calculating the mass after swelling and saturation at the moment to be m 4, by using a formula of F=G=mg, and reading out the indication number m 5 of the weighing indication panel (10) at the moment; and S6, calculating the volume swelling rate and the mass swelling rate according to the test result.
  4. 4. The method according to claim 3, wherein the specific calculation method of the electrolyte density ρ 0 in the step S1 is that the volume of the poured electrolyte is denoted as V, and the electrolyte density ρ 0 is calculated according to the formula ρ 0 =m 0 /V.
  5. 5. A method according to claim 3, wherein the volume V 1 of the adhesive sample in step S2 is determined by a die of fixed size of the tablet press, and the minimum mass m 1 of the adhesive sample is obtained according to formula m 1 =ρ 1 V 1 .
  6. 6. A method according to claim 3, wherein in the step S3, the lifting knob (31) is rotated to drive the lifting frame rod (3) to descend so as to fully submerge the filter bag (2) in the electrolyte, the indication number of the weighing table is m 2 , and the filter bag is discharged from the volume V 2 =（m 2 -m 0 ）/ρ 0 of the electrolyte.
  7. 7. The method according to claim 3, wherein the method for evaluating the swelling saturated state of the adhesive sample in the step S4 is specifically that the tension value F Pulling device of the tension sensor display panel (4) is observed in real time, and the monitoring is continuously carried out for 5-10min, and if the display number does not fluctuate or fluctuates within +/-0.01N, the adhesive sample is judged to reach the swelling saturated state.
  8. 8. The method of claim 3, wherein the calculation formula of the total volume of the electrolyte V 3 discharged by the filter bag and the binder sample at the time when the binder sample reaches the swelling saturated state in the step S4 is V 3 =(m 3 -m 5 )/ρ 0 , and the volume of the electrolyte V 4 =V 3 -V 2 =(m 3 -m 5 -m 2 +m 0 )/ρ 0 discharged by the swelled binder sample is obtained.
  9. 9. The method according to claim 3, wherein the volume swelling ratio Q 1 in the step S6 is calculated as Q 1 =（V 4 -V 1 ）/V 1 ×100%, and the mass swelling ratio Q 2 is calculated as Q 2 =（m 4 -m 1 ）/m 1 ×100%.
  10. 10. The adhesive swelling ratio testing device according to claim 2, wherein the function button (5) integrates peeling, switching on and off, zeroing operation functions.

Description

Device and method for testing swelling rate of adhesive Technical Field The invention belongs to the technical field of lithium ion battery testing, and particularly relates to a device and a method for testing the swelling rate of an adhesive. Background The electrochemical performance of the lithium battery as a core energy storage device in the new energy field directly depends on the stability of electrode materials, and the binder as a key material in the electrode is a core for firmly combining active substances, conductive agents and current collectors. At present, the binder for the lithium battery is mostly a polymer material with a cross-linked structure, and the material is generally not dissolved in electrolyte by virtue of a three-dimensional cross-linked network structure, but can absorb the electrolyte to generate swelling, and is particularly characterized by volume expansion and mass increase of the binder. The swelling behaviour of the binder has a significant impact on the overall performance of the lithium battery. When the swelling is excessive, the battery can bulge, and the increase of the thickness of the pole piece aggravates the corner wrinkles of the pole piece C. When the swelling is too small, the battery tends to be fluffy, and the battery performance is adversely affected, so that the swelling rate of the binder in the electrolyte is a very important evaluation index. However, since the binder material is mostly a polymer, the components are not uniform, and the crosslinking degree and the component ratio of different areas are different, so that the swelling degree of each area is not uniform, the morphology is irregularly changed after swelling, and the swelling volume cannot be obtained through simple calculation and measurement. The existing adhesive swelling ratio testing method mostly adopts an off-line weighing method or a volume measuring method, and has a plurality of limitations. The off-line weighing method needs to take out the swelled binder from the electrolyte and dry the swelled binder, and then the swelled binder is weighed, so that electrolyte residues or binder loss are easily caused in the operation process, and the measurement error is larger. The volumetric measurement method usually adopts naked eyes to observe the change of the height of the electrolyte level and converts the change into volume, but the measurement method also causes large errors, and the swelling saturation state of the adhesive immersed in the electrolyte is difficult to determine. In addition, most of the existing methods can only measure the mass swelling rate or the volume swelling rate independently, synchronous and accurate detection of two indexes cannot be realized, and the swelling characteristics of the adhesive are difficult to reflect comprehensively. In view of the above technical drawbacks, there is a need to develop a device and a method for testing the swelling rate of a binder in real time with high precision, which can synchronously measure the volume swelling rate and the mass swelling rate of the binder in an electrolyte, accurately judge and determine the swelling saturation state, improve the accuracy and the reliability of test data, and provide scientific and effective technical support for performance evaluation of the binder of a lithium battery. Disclosure of Invention In view of the above, the application provides a device and a method for testing the swelling ratio of a binder, which can judge the swelling saturation state and calculate the swelling degree by observing the readings of a tension sensor and a weighing display screen, can measure the volume of an irregular polymer in and after the swelling in real time, does not need to repeatedly take out the binder from electrolyte to determine the swelling saturation state in the measuring process, can replace the electrolyte in the swelling chamber, and is simple and convenient in principle and equipment, thereby solving the problems that the irregular swelling volume change and the swelling saturation state cannot be accurately tested in real time in the prior art. In order to achieve the above purpose, the invention adopts the following technical scheme: In one aspect of the application, an adhesive swelling rate testing device is provided, which comprises a glass cover 1, a filter bag 2, a lifting rack rod 3, a hook 6, a tension sensor 7, a swelling chamber 8 and a weighing platform 9, wherein the swelling chamber is arranged on the weighing platform and is used for containing electrolyte, the hook is arranged on the lifting rack, the lifting rack is lifted through an internal connecting rack rod structure, the lower part of the hook is connected with the tension sensor 7 and the filter bag 2 in sequence through a rope, the filter bag 2 can contain objects and enable the electrolyte to pass through, and the glass cover 1 is made of glass materials and is used for covering the outside of the whole testin