Epsilon Archive for Student Projects

Abstract

The purpose of this master thesis was to clarify how a standardized and replaceable battery module for working machines can be constructed together with the necessary components and systems. For example were battery technology, cell format, charge and discharge intervals, working temperature, the need of cooling etc. investigated. The purpose has also been to investigate which energy content and characteristics that are required of a battery module to meet the needs in the studied industries. The industries that were investigated were agriculture, forestry, military and construction. In order to find out what was required of the battery, semi-instructed interviews were held with people in the different industries. From the interviews it emerged that userfriendliness, safety, reliability and long battery life were important characteristics of the battery module. Other important features that emerged was that the battery module need a protective encapsulation material, that does not chemically react with the battery chemistry and resists external effects such as dirt, water, varying temperature and ultraviolet light from the sun. The battery module should also be protected against fire, explosion, vibration, collision, penetration and theft. What limited the design of the battery module was mainly the space in smaller working machines. The calculation models in Excel showed that a battery module of about 200 kWh would be enough for all studied working machines in the different industries, provided that the battery worked between 10–60 % of its total capacity and that replacement batteries were used if needed. The result also showed that an amount of maximal three battery replacements were enough to work throughout the day with a heavier machine. The battery module designed in this thesis had an energy content of 221 kWh, a module voltage of 601 V, a module capacity of 368 Ah and a physical size of 1.2x0.6x0.9 m3 without a cooling system. The price based on the price per energy content and BMS was estimated to 469 000 SEK and the mass based only on the number of battery cells was estimated to 832 kg.