Method for testing liquid leakage prevention performance of alkaline battery sealing ring

Abstract

The invention provides a method for testing the liquid leakage prevention performance of an alkaline battery sealing ring, which is used for detecting the liquid leakage prevention performance of the alkaline battery sealing ring by detecting the impact strength of a cantilever beam notch of a nylon material for the battery sealing ring, and specifically comprises the following steps: when the impact strength of the cantilever beam notch of the nylon material is 5-33.67 KJ / m, detecting the liquid leakage prevention performance of the alkaline battery sealing ring; and the liquid leakage prevention performance of the corresponding alkaline battery sealing ring reaches the standard. Based on the discovery of relevance between cantilever beam notch impact strength of a nylon material and liquid leakage prevention performance of the alkaline battery sealing ring, a novel method for testing the liquid leakage prevention performance of the alkaline battery sealing ring is developed by breaking through the conventional method, the testing time is greatly shortened, and the testing efficiency is improved. The battery liquid leakage risk when the nylon material is used as the alkaline battery sealing ring can be pre-judged before use, irreversible loss is avoided for battery manufacturers, meanwhile, waste of battery raw materials is reduced, and improvement of the overall quality and market competitiveness of the battery is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of performance testing of battery sealing rings, and particularly to a method for testing the liquid leakage prevention performance of alkaline battery sealing rings. Background Art

[0002] Nylon 610 occupies an important position in the nylon family. It is a polyamide engineering plastic formed by polycondensation of hexamethylenediamine and sebacic acid. Its properties are similar to those of nylon 66 in many aspects, and at the same time, it has advantages such as low water absorption, good dimensional stability of products, excellent electrical insulation, and low stiffness. These characteristics make it an ideal material for battery sealing rings.

[0003] However, there are certain problems with the nylon materials used for battery sealing rings in the prior art. As the storage time increases, the battery is prone to liquid leakage, which not only affects the service life of the battery but also may pose potential hazards to the environment and users.

[0004] Generally speaking, the reasons for liquid leakage of alkaline batteries can be roughly divided into two types. One is material rupture under high-temperature assessment. This structural rupture will cause the material to directly leak liquid, which is mainly related to the physical and chemical properties of the nylon material itself. Another factor is that alkaline vapor slowly seeps out from the central hole of the sealing ring and slowly forms black spots on the bottom cover of the battery, thus forming a black cover, and then slowly leaks liquid over time. There are many influencing factors for this phenomenon, including the size of the central hole diameter, the matching degree between the copper pin and the sealing ring, the type of electro-acupuncture glue coated on the copper pin, and the type of sealing ring material, etc. It can be seen that the performance of the sealing ring nylon material has an obvious impact on the black cover and liquid leakage of alkaline batteries.

[0005] In order to avoid the phenomenon of black cover and liquid leakage easily occurring in batteries after long-term use due to the insufficient performance of the sealing ring nylon material, currently, the battery is subjected to a liquid leakage prevention performance test before leaving the factory. The specific test method is: making the nylon material into a battery sealing ring, assembling it into a battery, then putting the battery into an oven at 60°C and 90% RH for 60 days, and observing the liquid leakage or black cover situation of the battery to measure whether the alkaline battery can be placed at room temperature for more than 5 years without liquid leakage and black cover. However, the existing liquid leakage prevention performance test method has obvious deficiencies: on the one hand, the test takes too long and cannot meet the requirements of rapid production and quality control; on the other hand, especially for battery manufacturers, this method cannot timely detect potential liquid leakage problems of the nylon material as an alkaline battery sealing ring before use. Once a problem is found, irreversible losses are often caused, seriously affecting the overall quality and market competitiveness of the battery. Moreover, the test requires assembling the battery into a complete product, and the battery samples cannot be reused after the test is completed, resulting in waste of raw materials. Summary of the Invention

[0006] The object of the present invention is to provide a method for testing the liquid leakage prevention performance of the sealing ring of an alkaline battery.

[0007] The technical solution for achieving the object of the present invention is: a method for testing the liquid leakage prevention performance of the sealing ring of an alkaline battery, which detects the liquid leakage prevention performance of the sealing ring of the alkaline battery by detecting the notched Izod impact strength of the nylon material used for the battery sealing ring. The specific method is: when the notched Izod impact strength of the nylon material is 5 - 33.67 KJ / m, the corresponding liquid leakage prevention performance of the sealing ring of the alkaline battery meets the standard.

[0008] Regarding the liquid leakage prevention performance of the sealing ring of an alkaline battery, currently, it is mostly adopted that: after cutting the nylon material used for the battery sealing ring into the required shape, assembling it into a battery, and evaluating the battery in an oven at 60°C and 90% RH to predict and measure the black cap liquid leakage time of the battery at room temperature. Generally speaking, if the battery is evaluated in an oven at 60°C and 90% RH for 60 days without liquid leakage and black cap, it means that it will not leak liquid and have a black cap when placed at room temperature for more than 5 years. And the notched Izod impact strength is mainly used to measure the brittleness of the material to prevent the materials assembled in the workshop from being too brittle and damaged. Therefore, generally, the higher the notched Izod impact strength of the material is, the better. However, the inventor of the present invention accidentally discovered during the long-term production practice process that: for alkaline batteries, the notched Izod impact strength of the nylon material is closely related to the liquid leakage prevention performance of the battery sealing ring; and through gradient tests, the change law of the liquid leakage prevention performance of the battery sealing ring with the notched Izod impact strength was investigated, and it was further found that: the smaller the notched Izod impact strength, the better the liquid leakage prevention performance of the sealing ring of the alkaline battery; but the smaller the notched Izod impact strength, the greater the difficulty in preparing the sealing ring of the alkaline battery and the worse the workshop adaptability. Therefore, when the notched Izod impact strength is 5 - 33.67 KJ / m, it can not only ensure that the alkaline battery is evaluated in an oven at 60°C and 90% RH for 60 days without liquid leakage and black cap, that is, the alkaline battery will not leak liquid and have a black cap when placed at room temperature for more than 5 years, but also has good workshop adaptability. Based on this, a new method for testing the liquid leakage prevention performance of the sealing ring of an alkaline battery, which predicts the liquid leakage prevention performance of the sealing ring of an alkaline battery through the notched Izod impact strength of the nylon material, has been developed by breaking through the convention. Since the testing process of the notched Izod impact strength mainly involves the specimen state adjustment time (about 16 hours) and the actual testing time (from a few minutes to several minutes), the total testing period of the notched Izod impact strength is usually within 17 hours, which is much less than the testing time (60 days) required by the existing testing method for the liquid leakage prevention performance of alkaline batteries. And it can predict the liquid leakage risk of the battery with the nylon material as the sealing ring of the alkaline battery before use, avoid irreversible losses to the battery manufacturer, improve the overall quality and market competitiveness of the battery, and at the same time, also avoid the waste of raw materials caused by the battery manufacturer testing the liquid leakage prevention performance with complete battery products.

[0009] Further, the notched Izod impact strength of the nylon material in the specific method is 10 - 22.43 KJ / m. At this time, the alkaline battery is tested in an oven at 60°C and 90% RH for 100 - 120 days without leakage and blackening of the cover, that is, the alkaline battery will not leak or blacken the cover after being placed at room temperature for more than 10 years.

[0010] Further, the melt mass flow rate of the nylon material in the specific method is 50 - 60 g / 10 min. If the melt mass flow rate is too large or too small, appearance defects such as mucosal, burrs, and bubbles will occur during the production of nylon materials. Therefore, the melt flow rate of the nylon material is preferably controlled within the range of 50 - 60 g / 10 min. Detailed implementation mode

[0011] The following details the preferred embodiments of the method for testing the anti-leakage performance of the sealing ring of an alkaline battery of the present invention.

[0012] A method for testing the anti-leakage performance of the sealing ring of an alkaline battery detects the anti-leakage performance of the sealing ring of an alkaline battery by detecting the notched Izod impact strength of the nylon material used for the battery sealing ring. The specific method is as follows: when the notched Izod impact strength of the nylon material is 5 - 33.67 KJ / m, the anti-leakage performance of the corresponding alkaline battery sealing ring meets the standard.

[0013] The method for testing the anti-leakage performance of the sealing ring of an alkaline battery of the present invention is a technical solution proposed based on the following test results. Specifically: 1. Comparison of the anti-leakage performance of the sealing rings of alkaline batteries made of nylon materials from different manufacturers Three types of nylon materials (nylon 610) purchased from different manufacturers were made into two types of alkaline batteries, LR03 and LR6, respectively, under the same conditions of battery sealing ring manufacturing method and battery assembly method. And the existing method of "testing the battery in an oven at 60°C and 90% RH" was used to evaluate its anti-leakage performance. The notched Izod impact strength and the corresponding blackening rate of the three types of nylon materials (materials A, B, and C) are shown in Tables 1 and 2 respectively.

[0014] Table 1

[0015] Table 2

[0016] It can be seen from Tables 1 and 2 that the smaller the notched Izod impact strength of the nylon material, the better the anti-leakage performance of the corresponding alkaline battery sealing ring, and the two are negatively correlated.

[0017] 2. Notched Izod impact strength gradient test Select six groups of nylon materials (nylon 610) with six gradients of Izod impact strength of the cantilever beam being 5.27 KJ / m 2 , 11.72 KJ / m 2 , 16.28 KJ / m 2 , 22.43 KJ / m 2 , 33.67 KJ / m 2 , 43.89 KJ / m 2 Under the conditions of the same battery seal ring manufacturing method and battery assembly method, make two types of alkaline batteries, LR03 and LR6 respectively, and use the existing method of "testing the battery in an oven at 60°C and 90% RH" to evaluate its anti-leakage performance. The performance indicators such as the Izod impact strength of the cantilever beam and the corresponding black cover rates of the six groups of nylon materials (1#, 2#, 3#, 4#, 5#, 6#) are shown in Table 3 and Table 4 respectively.

[0018] Table 3

[0019] Table 4

[0020] It can be seen from Table 3 and Table 4 that: (1) The Izod impact strength of the cantilever beam of the nylon material has a significant impact on the anti-leakage performance of the battery seal ring; for the two types of alkaline batteries, LR6 and LR03, when the Izod impact strength of the nylon material is between 5.27 and 22.43 KJ / M 2 , the corresponding batteries placed in an oven at 60°C and 90% RH can reach 100 days without blackening the cover and leaking liquid, and the anti-leakage performance of the alkaline battery seal ring meets the standard; as the Izod impact strength of the nylon material increases, the anti-leakage time gradually decreases; (2) For the LR6 type of alkaline battery, when the Izod impact strength of the cantilever beam increases to 33.67 KJ / M 2 , 43.89 KJ / M 2 respectively, it can reach 80 days and 60 days without blackening the cover and leaking liquid; for the LR03 type of alkaline battery, when the Izod impact strength of the cantilever beam increases to 33.67 KJ / M 2 , 43.89 KJ / M 2 respectively, it can reach 60 days and 30 days without blackening the cover and leaking liquid; therefore, considering comprehensively the higher standard that the anti-leakage performance of the battery seal ring reaches no leakage and no blackening of the cover for more than 10 years at room temperature and good workshop adaptability, it is best to select the nylon material with an Izod impact strength of the cantilever beam between 10 and 22.43 KJ / M 2 ; (3) The flexural properties and tensile properties of nylon materials with different Izod impact strengths of the cantilever beam do not change much, indicating that: the correlation between the flexural properties and tensile properties of nylon materials and the anti-leakage performance of battery seal rings is not significant.

[0021] 3. Influence of Bending Performance on the Leakage Prevention Performance of Battery Sealing Rings Six groups of nylon materials (nylon 610) with different flexural strengths or flexural moduli were selected. Under the conditions of the same battery sealing ring manufacturing method and battery assembly method, LR03 or LR6 alkaline batteries were made, and the existing method of "examining the battery in an oven at 60°C and 90% RH" was used to evaluate its leakage prevention performance. The performance indexes such as flexural strength and flexural modulus of the six groups of nylon materials (7#, 8#, 9#, 10#, 11#, 12#) and the corresponding black cover rates are shown in Table 5 and Table 6 respectively.

[0022] Table 5

[0023] Table 6

[0024] It can be seen from the results of Table 5 and Table 6 that the bending performance of nylon materials has no obvious influence on the leakage prevention performance of battery sealing rings.

[0025] In addition, the inventor also investigated the influence of the tensile properties (tensile yield stress and tensile modulus) of nylon materials on the leakage prevention performance of battery sealing rings. The results show that the tensile properties of nylon materials also have no obvious influence on the leakage prevention performance of battery sealing rings.

[0026] The above-mentioned notched Izod impact strength is 10 - 22.43 KJ / M 2 of nylon 610 materials, and the performance parameters are shown in Table 7 below.

[0027] Table 7

[0028] In addition, if the melt mass flow rate is too large or too small, it will cause appearance defects such as mucosal, burrs, and bubbles during the production of nylon materials. Therefore, the melt flow rate of the nylon material used for the battery sealing ring of the present invention is optimally in the range of 50 - 60 g / 10 min.

[0029] All the performance parameters (including heat distortion temperature under load, specific gravity, flexural strength, flexural modulus, notched Izod impact strength, melt mass flow rate, molding shrinkage rate, Rockwell hardness, tensile modulus, tensile yield strength, elongation at break, water absorption rate) mentioned in the method embodiment for testing the leakage prevention performance of the alkaline battery sealing ring of the present invention are detected in accordance with the relevant requirements of national standards.

[0030] The above are only embodiments of the present invention, and do not thus limit the patent scope of the present invention. Any equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall similarly be included within the patent protection scope of the present invention.

Claims

1. A method for testing the liquid leakage prevention performance of the sealing ring of an alkaline battery, characterized in that, It detects the liquid leakage prevention performance of the alkaline battery sealing ring by detecting the notched Izod impact strength of the nylon material used for the battery sealing ring. The specific method is as follows: when the notched Izod impact strength of the nylon material is 5 - 33.67 KJ / m, the liquid leakage prevention performance of the corresponding alkaline battery sealing ring meets the standard.

2. The method for testing the liquid leakage prevention performance of the sealing ring of an alkaline battery according to claim 1, wherein: In the specific method, the notched Izod impact strength of the nylon material is 10 - 22.43 KJ / m.

3. The method for testing the liquid leakage prevention performance of the sealing ring of an alkaline battery according to claim 1, characterized in that: In the specific method, the melt mass flow rate of the nylon material is 50 - 60 g / 10 min.

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