Оценка несущей способности контактного соединения полюсного вывода свинцовой аккумуляторной батареи

Abstract

Introduction. The data given in the article show that the problem of increase of fire safety at operation of vehicles is actual. The main purpose of the article is to develop a scientifically based method of examination of contact connections of pole terminals of starter batteries, which have signs of high transient resistance or change in geometrical shape in order to find out the reason of damage in the course of fire-technical expertise. Materials and methods. The researches were carried out with the use of a scanning-electron microscope JSM-6390LV with an attachment for energy-dispersive microanalysis. The objects of research were pole terminals of a lead-acid storage battery of European type and their tips. Contact surfaces of the tips were analyzed without preliminary sample preparation. Theoretical background (theory and calculations). A physical and mathematical model of ultimate load-bearing capacity of lead battery terminal, which corresponds to real design, has been developed. On this basis, there is formulated a computational and practical algorithm for expert analysis of its mechanical and geometrical characteristics. The solution has been simplified to short calculating formulas, allowing to estimate the contact load-bearing capacity. The applicability of the developed mathematical model to carrying out fire-technical exami­nations is shown by a concrete example. Results and discussion. Examples are given of car fires, which were caused by loss of load-bearing capacity in the contact of battery terminals with wire-end terminals during in the process of operation. Pictures of the result of high transient resistance on the contact surface and its elemental composition are given. Experimental data confirmed that the transfer of the material of the pole leads to the tips of wires in the form of drops of lead and its layers is a significant forensic feature in determining the cause of the fire. Conclusions. The method of determination of load-bearing capacity of contact of a lead battery pole to the wire end, on the basis of which it is possible to draw a conclusion about participation of great transient resistance in the contact to the subsequent fire, is offered. The data given in the article may be used by specialists during an expert examination of lead battery terminals, seized from places of fires, in order to establish the mechanism of their damage and, finally, the cause of a fire.