Rapid evaluation and selection method for bonding strength of battery sealant

Abstract

The invention discloses a rapid evaluation and selection method for the bonding strength of a battery sealant, which comprises the following steps of: 1) bonding two staggered and superposed nylon sheets together by using different sealants to form a plurality of samples to be tested; 2) placing a sample to be detected on the strength detection tool; (3) the lifting rod is started, the lifting rod drives the ejector rod to move downwards at a constant speed until the two nylon pieces are separated, and at the moment, the testing instrument displays the maximum force value occurring in the nylon piece separation process; and 4) replacing the to-be-tested sample, repeating the steps 1) to 3), recording the maximum force value for separating the nylon sheets bonded by the different sealants in each group, comparing the data of the maximum force values, and selecting the sealant used by the to-be-tested sample with the maximum force value. Compared with the prior art, the test and verification period of the alkaline battery sealant can be remarkably shortened, the bonding performance of the sealant is represented by peel strength detection data between nylon sheets, and the sealant is rapidly screened.

Description

Technical Field

[0001] This invention relates to battery processing technology, and more particularly to a method for rapid evaluation and selection of the bonding strength of battery sealant. Background Technology

[0002] In alkaline batteries, it is necessary to solve the problem of KOH alkaline electrolyte leakage between the stainless steel casing and the nylon material to avoid risks such as reduced battery storage time and corrosion damage to electrical appliances due to seal failure. The bonding strength between the sealant and the nylon material and casing directly determines the battery's lifespan; alkaline batteries even require a seal that can be maintained for 6-10 years.

[0003] Current methods for testing sealant strength primarily employ static battery evaluation, such as applying sealant to the opening of the battery's steel casing, assembling the battery, and then conducting tests, including high and low temperature cycling tests (-20℃ to 70℃) with a testing cycle of 5-7 days; high temperature and humidity tests (60℃ to 90RH) with a testing cycle of 60-100 days; and high temperature tests (90℃) with a testing cycle of 35-70 days. This results in long testing cycles for the sealant, and the test results deviate from the actual sealing performance in actual use. Therefore, there is an urgent need to establish an evaluation method that closely reflects the actual operating conditions of batteries and can quickly assess the bonding strength of sealants. Summary of the Invention

[0004] The purpose of this invention is to provide a rapid evaluation and selection method for the bonding strength of battery sealant.

[0005] The technical solution to achieve the objective of this invention is: a method for rapid evaluation and selection of the bonding strength of battery sealant, comprising the following steps: 1) Use different sealants to bond two nylon sheets that are stacked alternately to form several test samples; 2) Place one of the test samples on a strength testing fixture, the strength testing fixture including a testing platform, on which a first clamping mechanism and a second clamping mechanism are respectively installed. The first clamping mechanism includes a first gripper located on the lower side of the second clamping mechanism, the first gripper clamping the lower layer of the nylon sheet in the test sample; the second clamping mechanism includes a lifting rod and a second gripper, the lifting rod being vertically and vertically mounted on the testing platform, a testing instrument for sensing the pressure of the top material rod being fixedly mounted on the lifting rod, the second gripper being mounted on the bottom of the lifting rod, the second gripper clamping the top material rod, the axis of the top material rod being perpendicular to the horizontal plane, and the suspended part of the upper layer of the nylon sheet being located on the moving path of the top material rod; 3) Start the lifting rod, which drives the top material rod to move down at a constant speed until the two nylon sheets are separated. At this time, the test instrument displays the maximum force value that occurs during the separation of the nylon sheets. 4) Replace the sample to be tested and repeat steps 1) to 3), and record the maximum force value of the nylon sheet separation when bonded with different sealants in each group. Compare the data of each maximum force value and select the sealant used for the sample to be tested with the largest maximum force value.

[0006] Furthermore, the lifting rod is fixed to the nut of the lead screw lifting mechanism by a bracket.

[0007] Furthermore, a vernier displacement display device is installed on the lead screw lifting mechanism.

[0008] Furthermore, the bottom of the top rod is shaped like a sharp arrowhead.

[0009] The core function of sealant is to "block the penetration of media (gas, liquid, dust) through interface adhesion and its own deformation." Traditional static evaluation methods for batteries neglect the crucial issue that sealing failure in actual battery operation begins at the interface between the sealant and the nylon material. The strength of the sealant determines whether the bond between the sealant and the nylon material can be maintained in the long term: without sufficient strength support, the sealing performance will fail over time or due to environmental changes, and it is impossible to simulate the peeling characteristics caused by relative displacement between the material interfaces. The inventors have broken through the rigid thinking of traditional sealant sealing performance testing by constructing a detection model of interface peeling state, enabling direct evaluation of the interfacial peeling bond strength of the sealant. Compared with existing technologies, this invention can significantly shorten the testing and verification cycle of alkaline battery sealants, characterize the performance of the sealant by using the peeling strength test data between nylon sheets, and quickly screen the adhesive strength of the sealant. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the strength testing fixture described in this invention. Detailed Implementation

[0011] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0012] A rapid evaluation and selection method for the bonding strength of battery sealant, comprising the following steps: 1) Two nylon sheets 102, which are stacked in an alternating manner, are bonded together using two different sealants 101 to form two test samples 10; (Sample 1, produced in Shenzhen, Guangdong; Sample 2, produced in Nanping, Fujian). 2) Place one of the test samples in Figure 1The strength testing fixture shown includes a testing platform 1, on which a first clamping mechanism 2 and a second clamping mechanism 3 are respectively installed. The first clamping mechanism 2 includes a first jaw 21 for clamping the nylon sheet assembly 10, and the first jaw 21 is located on the lower side of the second clamping mechanism 3. The second clamping mechanism 3 includes a lifting rod 31 and a second jaw 32. A screw lifting mechanism 4 is installed on the testing platform 1. The lifting rod 31 is fixedly installed on the nut (not shown) of the screw lifting mechanism 4 by a bracket 33. The second jaw 32 is installed on the lifting rod 31. At the bottom, the second gripper 32 holds the top material rod 34, the axis of the top material rod 34 is perpendicular to the horizontal plane, and the bottom 341 of the top material rod 34 is in the shape of a sharp arrow. A test instrument 5 for sensing the pressure of the top material rod 34 is fixedly installed on the lifting rod 31. A vernier displacement display device 6 is installed on the screw lifting mechanism 4. The nylon sheet group 10 includes two staggered nylon sheets 102. The overlapping positions of the two nylon sheets 102 are bonded and fixed by sealant 101. The suspended part 1021 of the upper nylon sheet 102 is located on the moving path of the top material rod 34. 3) Start the lifting rod 31. The lifting rod 31 drives the top material rod 34 to move down at a constant speed until the two nylon sheets 102 are separated. At this time, the test instrument displays the maximum force value that occurs during the separation of the nylon sheets 102. 4) Test the two commercially available sealants according to steps 1)-3 above, and record the maximum force value of nylon sheet separation. The results are shown in Table 1.

[0013] Table 1

[0014] Table 1 shows that sample 1 has the best bonding strength.

[0015] Next, the two sealants tested above were applied to battery production on the applicant's conventional production line to produce alkaline battery LR03 finished products. This batch of finished batteries was then aged under high temperature and humidity conditions, and leakage was monitored during the aging process. The monitoring results are shown in Table 2. (Note: The blackening rate of the battery refers to the phenomenon where, during storage in a high temperature and humidity environment, the plating on the bottom cover of the alkaline battery reacts with the sealant due to leakage of alkaline solution, forming a black compound adhesion.) Table 2

[0016] Combining the test results in Tables 1 and 2, it is evident that the battery prepared from Sample 1 exhibits a later onset time and a lower probability of sealant failure under high temperature and humidity conditions. This verifies that the rapid evaluation and selection method for the sealant bonding strength of the battery in this invention requires only a few hours of testing time. Compared to the conventional long-term testing methods involving five days or more under high temperature and humidity conditions, this method allows for earlier identification of sealants with excellent performance in alkaline batteries and enables rapid screening of different types of sealants.

[0017] The testing instrument described in this invention can be a common force gauge, the structure of which is existing technology and will not be described in detail here.

[0018] The lifting mechanism that drives the lifting rod to rise and fall can be a manual screw lifting mechanism, a pneumatic screw lifting mechanism, or other conventional linear displacement drive mechanisms in the mechanical field, which will not be elaborated here.

[0019] The shape of the top rod is not limited to that shown in the embodiment, but the top rod with a sharp bottom facilitates the application of force to the nylon sheet.

[0020] The structure of the vernier displacement display device is existing technology. Adding a vernier displacement display device is beneficial for controlling the movement speed.

[0021] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent process transformations made using the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for rapid evaluation and selection of the bonding strength of battery sealant, characterized in that: It includes the following steps: 1) Use different sealants to bond two nylon sheets that are stacked alternately to form several test samples; 2) Place one of the test samples on a strength testing fixture, the strength testing fixture including a testing platform, on which a first clamping mechanism and a second clamping mechanism are respectively installed. The first clamping mechanism includes a first gripper located on the lower side of the second clamping mechanism, the first gripper clamping the lower layer of the nylon sheet in the test sample; the second clamping mechanism includes a lifting rod and a second gripper, the lifting rod being vertically and vertically mounted on the testing platform, a testing instrument for sensing the pressure of the top material rod being fixedly mounted on the lifting rod, the second gripper being mounted on the bottom of the lifting rod, the second gripper clamping the top material rod, the axis of the top material rod being perpendicular to the horizontal plane, and the suspended part of the upper layer of the nylon sheet being located on the moving path of the top material rod; 3) Start the lifting rod, which drives the top material rod to move down at a constant speed until the two nylon sheets are separated. At this time, the test instrument displays the maximum force value that occurs during the separation of the nylon sheets. 4) Replace the sample to be tested and repeat steps 1) to 3), and record the maximum force value of the nylon sheet separation when bonded with different sealants in each group, and compare the magnitude of each maximum force value data, and select the sealant used for the sample to be tested with the largest maximum force value.

2. The method for rapid evaluation and selection of battery sealant bonding strength according to claim 1, characterized in that: The lifting rod is fixed to the nut of the lead screw lifting mechanism by a bracket.

3. The method for rapid evaluation and selection of battery sealant bonding strength according to claim 1, characterized in that: The lead screw lifting mechanism is equipped with a vernier displacement display device.

4. The method for rapid evaluation and selection of battery sealant bonding strength according to claim 1, characterized in that: The bottom of the top rod is shaped like a sharp arrowhead.

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