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毕业论文网 > 毕业论文 > 机械机电类 > 过程装备与控制工程 > 正文

PEM燃料电池关键构件材料的疲劳行为研究毕业论文

 2022-03-14 07:03  

论文总字数:37761字

摘 要

PEM燃料电池(质子交换膜燃料电池)因为其比功率高、启动快等特点,成为燃料电池的首选技术。自20世纪90年代以来,燃料电池研发在国际范围内蓬勃兴起。目前影响燃料电池广泛商业化的主要技术难点来自于燃料电池的价格与耐久性问题。燃料电池的耐久性问题尤为突出,主要是因为车载工况对燃料电池的影响,比如频繁起停、快速变载等此类非稳态操作以及低温、杂质环境的影响等,都会导致燃料电池加速老化,由此引起使用寿命的缩短。弹性体垫片材料作为质子交换膜(PEM)燃料电池的密封关键组件,用来密封隔离阳极和阴极的反应气体(氢气和氧气/空气)。PEM燃料电池运行过程中,弹性体垫片材料长时间地暴露在燃料电池里的酸性环境、湿空气和氢环境中,并承受机械压缩载荷。若是出现老化(如失弹),导致密封失效,PEM燃料电池将可能发生泄漏,这不仅将影响PEM燃料电池的电化学性能,还会引发安全问题。因此,PEM燃料电池弹性体垫片材料性能的耐久性和稳定性对PEM燃料电池高效、可靠和长久地运行至关重要。本文的主要工作和结论如下:

(1)本文从众多的橡胶生产厂家以及橡胶生胶牌号中,针对PEM燃料电池密封垫片橡胶材料,选出了一种具有代表性的硅橡胶作为研究对象,制备了一种甲基乙烯基硅橡胶。

(2)基于甲基乙烯基硅橡胶材料,提出了硅橡胶材料的硫化方法,并按照该硫化方法改变其硫化工艺制备了后面的橡胶弹性体材料。

(3)利用对比分析的方法,研究了力学性能较好的硫化橡胶试件所对应的初始硫化条件,逐步确定最佳的硫化温度。为垫片材料的性能优化提供科学方法。

(4)研究了硫化胶材料的力学性能(包括拉伸强度、压缩应力应变、压缩永久变形、压缩应力松弛等)测定的基本原理、仪器设备、试样及其制备、测定过程步骤、数据处理方法等。通过拉伸试验得出:材料抗拉强度和100%定伸应力在160℃时升至最大,说明其综合的拉伸性能是最佳的。四种硫化温度下试样的延伸率均超过600%,说明材料的分子间作用力较大,不易受外力破坏。

压缩弹性模量是通过压缩应力应变实验测得。通过实验数据可以看出,在硫化温度为160℃的时候,VMQ材料的压缩弹性模量最大,说明在相同应力的情况下,应变最小,材料的变形量也最小,回弹性能最佳。

压缩永久变形在开始阶段变化量最大,随着时间的推移,永久变形量越来越不明显,24h的永久变形率是最大的,综合四种硫化温度得出的实验数据,无论是在24h、72h、168h,160℃时的压缩永久变形量都是最小的,即此时材料的压缩永久变形性能较好,压缩永久变形率最小。

(5)通过进行曲挠龟裂测定的实验得出:在硫化温度为160℃时,材料开始出现针刺点的时间最晚,所需的千周数最长,虽然在出现裂纹后也很快出现了疲劳失效,但是其抗疲劳性能还是显著优于其他硫化温度下的VMQ材料。

关键词:弹性体垫片 甲基乙烯基硅橡胶 机械性能 硫化温度 疲劳性能

ABSTRACT

Proton exchange membrane fuel cell is the preferred technology for fuel cells, it has a high power, fast start and so on. Since the 20th century, 90 years, fuel cell research and development in the international context of the vigorous rise. The main technical difficulties that affect the commercialization of fuel cells are from the life and cost of fuel cells. low temperature, impurity environmental impact, etc., will lead to accelerated fuel cell attenuation, resulting in shortened life The Elastomeric gasket material is used as a sealing key component for proton exchange membrane (PEM) fuel cells to seal the reaction gases (hydrogen and oxygen / air) that isolate the anode and cathode. During the operation of the PEM fuel cell, the elastomeric gasket material is exposed to the acidic environment, humid air and hydrogen environment of the fuel cell for a long time and subjected to mechanical compression loads. If there is an aging (such as loss), resulting in sealing failure, PEM fuel cell will leak, which will not only affect the electrochemical performance of PEM fuel cell, but also lead to safety problems. Therefore, the durability and stability of PEM fuel cell elastomer gasket material properties are critical to the efficient, reliable and long-term operation of PEM fuel cells. The main work and conclusions of this paper are as follows:

  1. This paper from a large number of rubber manufacturers and rubber raw rubber grades, for PEM fuel cell gasket rubber material, selected a representative silicone rubber as a research object,a methyl vinyl silicone rubber was prepared.

(2) Based on the methyl vinyl silicone rubber material, the vulcanization method of the silicone rubber material was proposed, and the rubber elastomer material was prepared according to the vulcanization method.

(3) Using the method of comparative analysis, the initial vulcanization conditions corresponding to the vulcanized rubber specimens with good mechanical properties were studied, and the optimum vulcanization temperature was determined step by step. To provide scientific methods for the optimization of the performance of the gasket material.

(4) The basic principle, instrument and equipment, sample preparation and determination of the mechanical properties of the vulcanizate (including tensile strength, compressive stress strain, compression set, compressive stress relaxation, etc.) are studied. Methods and so on. Through the tensile test, the tensile strength and the 100% modulus of the material were increased at 160 ℃, which indicated that the tensile properties were the best. Four kinds of vulcanization temperature of the sample elongation of more than 600%, indicating that the material between the intermolecular force is greater, less susceptible to external damage.

The compressive elastic modulus is measured by compressive stress and strain experiments. It can be seen from the experimental data that the compressive elastic modulus of the VMQ material is the largest when the vulcanization temperature is 160 ℃, indicating that the strain is the smallest under the same stress, the deformation of the material is the smallest and the springback performance is the best.

Compressive permanent deformation is the largest in the initial stage, and the permanent deformation is becoming more and more obvious with the passage of time. The permanent deformation rate of 24h is the largest, and the experimental data obtained from four kinds of vulcanization temperature, 72h, 168h, 160 ℃ when the compression deformation is the smallest, that is, the material at this time the compression of the permanent deformation performance is better, the minimum compression deformation rate.

  1. Through the experiment of flexural cracking test, it is concluded that the time of starting the acupuncture point at the time of vulcanization temperature is 160 ℃, the maximum number of weeks is required, although it is fast after crack Fatigue failure occurs, but its anti-fatigue performance is significantly better than other curing temperature of the VMQ material.

Keywords: elastomer gasket Polymethyl -vinyl siloxane rubber(MVQ) Mechanical behavior Vulcanization temperature Fatigue performance

目 录

摘 要 I

ABSTRACT I

第一章 绪论 1

1.1引言 1

1.1.1课题来源、选题依据和背景情况 1

1.1.2 课题研究目的及工程应用价值 2

1.2 燃料电池简介 3

1.2.1燃料电池的发展动向 3

1.2.2燃料电池的工作原理 3

1.2.3 燃料电池的结构 4

1.2.4 PEM燃料电池(质子交换膜燃料电池)简介 4

1.3弹性体垫片概述 5

1.3.1弹性体垫片简介 5

1.3.2弹性体垫片的研究进展 8

1.4 本文主要的研究内容 8

第二章 PEM燃料电池垫片材料配方设计及制备 15

2.1引言 15

2.2 PEM燃料电池垫片材料配方设计 15

2.2.1 原材料的选取 16

2.2.2 硅橡胶材料的配方设计 16

2.3 PEM燃料电池垫片材料试样制备方法 17

2.3.1 混炼 18

2.3.2 材料硫化特性参数测定 19

2.3.3 硫化 19

2.4 本章小结 22

第三章 PEM燃料电池密封垫片橡胶材料机械性能研究 23

3.1 引言 23

3.2硫化温度的选取及橡胶材料制备 23

3.2.1 配方设计及硫化温度的选取 24

3.2.2 称料混炼及硫化制备制样 25

3.3橡胶材料机械性能试验设备 26

3.4橡胶材料机械性能测试标准 26

3.4.1拉伸性能的测定 26

3.4.2压缩永久变形性能的测定 27

3.4.3压缩应力应变性能的测定 28

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