基于氢气充放试验及数值模拟的储氢气瓶安全评价

储氢气瓶是新能源汽车的重要储能设备,其可靠性直接关系到汽车的安全性。研究了不同环境温度下,35 MPa铝合金内胆车用储氢III型气瓶在充放气时的最终温度和应力分布情况,并对其安全性进行了评价。借助试验测试平台,在不同温度下进行了实际充放试验。试验过程中无漏气现象,且最终温度符合要求,表明储氢气瓶在试验条件下是安全的。由此,在获得了储氢气瓶充放时热响应规律的基础上,对不同温度下的氢气充放过程进行了数值模拟,得到其应力分布情况。结果表明,储氢气瓶复合层的应力远小于其材料抗拉强度,即内胆和复合层的强度均可视为满足要求。研究结果可为储氢气瓶的试验开展、安全评价、寿命预测提供依据。

Safety evaluation of hydrogen storage tank based on the hydrogen filling and emptying test and the numerical simu-lation mode

This paper intends to present the author’s investigation and research results of the final temperature and the stress distribution of the hydrogen storage tank at the different service temperatures in the refilling and emptying process based on the safety evaluation being done. As is known,hydrogen storage tank is the important energy storage device for new-energy vehicles,whose reliability plays a significant role in guaranteeing the energy saving and storage. And,speaking in a detailed way,the tank is composed of the aluminum alloy liner and a winded carbon fibers/epoxy composite layer,whose design pressure should be set about at 5 MPa. To check its functions,the filling and emptying test has to be performed by means of an experimental test rig specific for such hydrogen storage tanks. The results of our study indicate that no leakage has been found with the hydrogen storage tank in the testing process,till the final temperature of the tank can be pushed up to the limited safe range according to the national standard,thus proving that the tank proves safe under the needed testing conditions. What is more,based on the testing results of the mechanical autofrettage,a numerical simulation can be conducted for the stress distribution on the tank surface after the test. The stress on the liner tends to be slightly beyond the yield strength of the material,whereas the stress on the composite layer proves to be far lower than the tensile strength of the material. Nevertheless,considering that the pressure on the hydrogen storage tank has to be predominantly sustained by the composite layer,the strength of the entire hydrogen storage tank has to be highly qualified enough to meet the demands of its application. In other words,the tank should be made safe enough for its filling and emptying process in the actual application practices. And,therefore,what we have done in this paper should be sufficient enough to provide the technical support for testing safety evaluation,as well as the service life prediction of such hydrogen storage tanks,which has had sufficient significance in engineering.