Experimental Evaluation of “Memory Effect” on a Nickel-Metal Hydride Power Battery

Shallow discharge cycling have been performed on a Nickel Metal Hydride battery specifically designed for automotive application. The voltage depression phenomenon, commonly named “Memory effect”, has been reproduced under controlled conditions. The growth process of the voltage lowering as function of shallow discharge cycle number and the cycle discharge depth has been investigated. The influence of the voltage depression on the battery performances has been investigated too. The paper describes the main test results and proposes a technique to take into account the battery memory effect at the design stage of a Ni-MH battery storage system, with particular reference to systems for electric or hybrid vehicles

Urban textiles, a design workshop

This discussion presents Urban Textiles, a design workshop with students from Politecnico di Torino in Ameno (Novara, Italy). By working with an ecodesign approach, the workshop led to the production of pieces of street furniture, by using waste material provided from local industries. Those products acted as info-design tools and gave local and incoming communities a new vision about the identity of the territory. The paper focuses on the performing feature of this design experience and how this approach increased the connections between landscape, people and industry. The Urban Textiles workshop is an example of an action-research process applied to specific territory: the skills of design are enhanced to explore the reality in which we work, to analyze the production processes and to introduce changes to create innovation

Modelling of a PEFC-SC hybrid electric drive-train

For electric vehicular propulsion the generation of electricity can be made using systems based on Proton Exchange Membrane Fuel Cells, that allow vehicle operation with zero emissions in urban environments. It is often advantageous to couple these Fuel cells with supercapacitors for improved performance. For correnct design of different parts of this hybrid generation system it is important to have suitable models for all components, to be insterted in simulation programs. This paper is intended to propose these models, posing the maximum care in choosing the right complexity level to obtain a good balance between model manageability and precision of results

A Comparison of different fuel-cell based drive train typologies to be used on two-wheel vehicles

based electric supply systems [4,8,11]. Under funding from Piaggio & C. S.p.A. they have developed a MATLAB/SIMULINK simulation package for PEM fuel-cell vehicles either with or without the presence of electro-chemical energy storage. The paper shows a comparison of two-wheel vehicles equipped with electric drive-trains in which the electricity generators are composed by: 1. PEFC system 2. PEFC system plus electrochemical storage constituted by a super-capacitor 3. PEFC system plus electrochemical storage constituted by a high power Ni-MH battery The comparison is performed based on realistic vehicle and cycle data, coming from Piaggio’s experience. Since the second and third topologies are hybrids (different independent sources can generate the power needed for propulsion), for them suitable control strategies defined prior to perform actual performance compari-son

Insieme / Collaborazioni inclusive

Come designer e antropologi da anni lavoriamo nell’accompagnare la trasformazione dei Centri di accoglienza per le persone senza dimora verso una dimensione di dignità e rispetto della persona; per noi questo significa mettersi in ascolto di chi beneficerà del cambiamento che i progetti produrranno; significa valorizzarne le capacità, le speranze, facendo anche i conti con la fragilità e con il senso di precarietà che vive chi non gode di una dimora stabile e sicura

Memory effect on a Nickel - Metal Hydride Automotive Battery

Tests on a Nickel Metal Hydride battery specifically designed for automotive application have been performed with joint funding from the University of Pisa and Arsenal Research. The well known phenomenon commonly named "Memory effect" has been reproduced in a way that makes it possible to clarify the relationships between the involved parameters. The paper describes the main results of the tests, and proposes a technique to evaluate the battery memory effect at the design stage of a system, with particular reference to electric or hybrid vehicle application

Experimental evaluation of aging indicators for lithium–iron–phosphate cells

Degradation mechanism of batteries has to be carefully studied when considering their utilization in electrical power systems. This paper presents the results of an extensive experimental campaign, through which three different lithium–iron–phosphate (LFP) cells were subjected to different electrical cycling stresses. The purpose of the campaign was to evaluate the cells’ aging, as well as to try to find parameters on the cell behavior before its end of life, able to act as state-of-life (SOL) (or aging) indicators. The considered stress consists of the cyclic repetition of fixed-duration discharge steps, followed by full charge phases. The three cells under study were subjected to the very same stress pattern but with three different discharge and charge power levels: low, medium, and high. The results showed that the end-of-discharge voltage and the cell internal resistance can be used as good SOL indicators. However, both are significant functions of the cell conditions, such as the state of charge (SOC) and the cell temperature