Standardization in Electric Vehicles

Standardization in Electric Vehicles Paulo G. Pereirinha 1,2,3, João P. Trovão 1,2, 1 IPC-ISEC, Polytechnic Institute of Coimbra, R. Pedro Nunes, P-3030-199 Coimbra, Portugal 2 Institute for Systems and Computers Engineering at Coimbra (INESC-Coimbra), Portugal 3 APVE, Portuguese Electric Vehicle Association. Participate at the Portuguese CTE 69 and CT146 ppereiri@isec.pt Abstract- Electric Vehicles, EVs, are expected to contribute definitively to the sustainable mobility. However, in order to allow a faster market penetration, standardization is of extreme importance. Indeed, for comfortable and secure vehicle utilization, there are many aspects of EVs that need to be standardized. The primary objective of this paper is to present, on a compact form, the standardization framework in the field of electric vehicles and hybrid electric vehicles, the most important and urgent standardization activities going on, and the standardization activities in Portugal. A secondary objective is to give the references allowing a non expert on standards to seek for the actualized state of the standardization activities concerning EVs in the future. I. INTRODUCTION Electric Vehicles, EVs, are expected to contribute definitively to the sustainable mobility [1][2]. However, in order to allow a faster market penetration, standardization is of extreme importance. Indeed, for comfortable and secure vehicle utilization, there are many aspects of EVs that need to be standardized as, for example, the plugs for charging, the chargers voltages, the communication between the vehicle and the chargers, fast charging systems and respective billing, security measures for vehicle safety and safety of persons against electric shock, on-board electric energy storage for propulsion and vehicle energy performance and energy measurements. In this paper, the standardization framework in the field of electric vehicles and hybrid electric vehicles (HEVs) is firstly presented, followed by the most important and urgent standardization activities going on, and finally the standardization activities in Portugal are presented. Fig. 1. IEC s structure [3] B. International Organization for Standardization, ISO Founded in 1946 in London and officially beginning its activities on 23 February 1947, in Geneva, Switzerland, ISO is the world's largest developer and publisher of International Standards, dealing with the non-electrical technologies. It is constituted by 160 national standards institutes coordinated by a Central Secretariat in Geneva. In order to avoid different acronyms in different languages it was decided to use as short name, "ISO". This was derived from the Greek isos, which means "equal". The ISO structure is represented in Fig. 2 and in 2011 has nearly 220 technical committees. II. GLOBAL STANDARDIZATION AND ELECTRIC VEHICLE STANDARDIZATION FRAMEWORK At a worldwide level, standardization is mainly under the competence of two institutions: the International Electrotechnical Commission (IEC) [3], founded on 1906, and the International Organization for Standardization (ISO) [4], founded on 1946. A. International Electrotechnical Commission, IEC IEC is the world s leading organization preparing and publishing International Standards for all electrical, electronic and associated technologies. Its structure can be seen in Fig. 1. In 2010, it had around 174 Technical Committees (TCs) and Subcommittees (SCs). TCs report to the Standardization Management Board and can form SCs to deal with items on the TCs work programme. TC membership is composed of the IEC National Committees (NCs) that can participate in the work of any TC either as Participating members (P-Members) or Observer members (O-Members). Fig. 2. ISO s structure [4]

C. European and National level standardization organizations Besides ISO and IEC, in the field of EVs and HEVs there are also some relevant standardization organizations at European and National level, namely: CEN, the European Commission for Standardization. Its TC 301 Road Vehicles, is responsible for electric road vehicles. CENELEC, the European Committee for Electrotechnical Standardization. EVs are dealt with by the TC 69X Electrical systems for electric road vehicles. In the U.S., the Society of Automotive Engineers (SAE). In Japan, the Japanese Electric Vehicle Association (JEVA). In Portugal, by delegation of the Portuguese Quality Institute, IPQ, the Portuguese Electric Vehicle Association, APVE, is the sector standardization organism for electric road vehicles. It has two TCs: CTE 69 Electric Road Vehicles, and CT146 Electric Systems for Electric Road Vehicles. D. Electric Vehicle Standardization Responsibility? An important issue appears concerning the EVs standardization responsibility. As a road vehicle, the EV (and the HEV) is under the competence of ISO, namely, of ISO TC22/SC21 Electrically propelled road vehicles, which has three working groups (WGs): WG 1 - Vehicle operation conditions, vehicle safety and energy storage installation; WG 2 - Definitions and methods of measurement of vehicle performance and of energy consumption; WG 3 - Lithium Ion traction Batteries. But, an electric vehicle can also be considered as an electrical device, which is in the competence of IEC, namely the IEC TC69 Electric road vehicles and electric industrial trucks. IEC TC69 has two active WGs: WG 2 - Motors and motor control systems; WG 4 - Power supplies and chargers. These two TCs, ISO TC22/SC21 and IEC TC69, have been collaborating since its foundation. Nevertheless, some discussions have arisen in the past due to various intersections on the work division by the two groups. This was solved by a consensus agreement in 1996 [5], defining the competences of the respective committees, as can be seen in Table 1. A recent ISO/IEC Memorandum of Understanding (MoU) [6][7], valid for all types of road vehicles and respective equipments, clarified the collaboration rules and modes. TABLE I BASIC WORK DIVISION BETWEEN ISO AND IEC COMMITTEES ISO Work related to the electric vehicle as a whole IEC Work related to electric components and electric supply infrastructure A list of ISO and IEC committees responsible for and involved in standardization of electrotechnology for road vehicles as by 2010 is also presented in [7]. III. MOST IMPORTANT STANDARDIZATION ACTIVITIES GOING ON IN THE ELECTRIC VEHICLES FRAMEWORK From the ISO/IEC Memorandum of Understanding, resulted the standardization activity presented in Table II (IEC/ISO on-going projects by 2010). TABLE II IEC/ISO ON-GOING PROJECTS [7] Electrotechnology/ IEC TC/SC ISO TC/SC Project Starter batteries TC 21 TC 22 Secondary lithium cells IEC 62660-1 Ed 1.0 IEC 62660-2 Ed. 1.0 TC 21/SC 21A/TC 69 TC 22/ SC 21 Lithium batteries battery pack and system level ISO 12405-1 Ed. 1.0 ISO 12405-2 Ed. 1.0 EV Charging System IEC 61851 series Vehicle to grid communication interface (JWG V2G CI) ISO 15118 Plugs and Socket-outlets IEC 62196 series TC 21/SC 21A/TC 69 TC 22/SC 21 TC 69 TC 22/SC 21 TC 69 TC 22/SC 3 SC 23H TC 22/SC 3 Lamps, lamp holders and caps SC 34A/SC 34B TC 22/SC 8 Radio interferences (>= 9 KHz) CISPR D caused by road vehicle electrical systems EMC emissions on low frequency SC 77A (<9 khz) disturbances and basic EMC immunity standards for the whole frequency range EMC immunity for EV charging TC 69 systems EMC immunity for vehicle and its TC 77 equipment Organization in bold has the administrative lead These projects are leaded by different IEC TC/SC or ISO TC/SC (Table II) and are at different developments level, as will be shown following. A. Standards and projects under the direct responsibility of ISO TC22/SC21 The International Standards developed by ISO TC and SC pass a multistep-step process, to which correspond the International harmonized stage codes in Table III. TABLE III STAGES AND CODES IN ISO STANDARDS DEVELOPMENT [8][9] Stage Associated Document 00 Preliminary stage 10 Proposal stage NP: New Proposal 20 Preparatory stage WD: Working Draft (a WG prepare a WD to the committee) 30 Committee stage DIS: Draft International Standard 40 Enquiry stage FDIS: Final Draft International Standard 50 Approval stage (Vote for: Yes/No or reconsideration) 60 Publication stage ISO International Standard 90 Review Stage 95 Withdrawal Stage A document in one stage can be at one of the substages presented in Table IV. For example, a project with the code 60.60 is at Publication stage+ Completion of main action, that is, 60.60 means International Standard published. A full stage codes table with a visual representation of the development stages can be found at [9].

TABLE IV SUBSTAGES AND CODES IN ISO STANDARDS DEVELOPMENT Substage 00 Registration 20 Start of main action 60 Completion of main action 90 Decision Substages 92 Repeat an earlier phase 93 Repeat current phase 98 Abandon 99 Proceed The standard and/or projects in Table V have been published, while those in Table VI are under development by May 2011 [10]. TABLE V STANDARDS/PROJECTS PUBLISHED BY ISO TC22/SC21 Standard and/or project ISO 6469-1:2009 Electrically propelled road vehicles Safety 60.60 specifications Part 1: On-board rechargeable energy storage system (RESS) ISO 6469-2:2009 Electrically propelled road vehicles Safety 60.60 specifications Part 2: Vehicle operational safety means and protection against failures ISO 6469-3:2001 Electric road vehicles Safety specifications 90.92 Part 3: Protection of persons against electric hazards ISO 6469-3:2001/Cor 1:2003 60.60 ISO 8713:2005 Electric road vehicles Vocabulary 90.92 ISO 8714:2002 Electric road vehicles Reference energy consumption and range Test procedures for passenger cars and light commercial vehicles ISO 8715:2001 Electric road vehicles Road operating 90.60 characteristics ISO/TR 11954:2008 Fuel cell road vehicles Maximum speed 60.60 measurement ISO/TR 11955:2008 Hybrid-electric road vehicles Guidelines 60.60 for charge balance measurement ISO 23273-1:2006 Fuel cell road vehicles Safety specifications Part 1: Vehicle functional safety ISO 23273-2:2006 Fuel cell road vehicles Safety specifications Part 2: Protection against hydrogen hazards for vehicles fuelled with compressed hydrogen ISO 23273-3:2006 Fuel cell road vehicles Safety specifications Part 3: Protection of persons against electric shock ISO 23274:2007 Hybrid-electric road vehicles Exhaust 90.60 emissions and fuel consumption measurements Non-externally chargeable vehicles ISO 23828:2008 Fuel cell road vehicles - Energy consumption 90.60 measurement Vehicles fuelled with compressed hydrogen TABLE VI STANDARDS/PROJECTS UNDER DEVELOP. BY ISO TC22/SC21 Standard and/or project ISO/FDIS 6469-3 Electrically propelled road vehicles Safety 50.20 specification Part 3: Protection of persons against electric shock ISO/DTR 8713 Electric road vehicles Vocabulary 30.60 ISO/PRF 12405-1 Electrically propelled road vehicles Test 50.20 specification for lithium-ion traction battery packs and systems Part 1: High-power applications ISO/DIS 12405-2 Electrically propelled road vehicles Test 40.60 specification for lithium-ion traction battery packs and systems Part 2: High energy application ISO/NP 12405-3 Electrically propelled road vehicles - Test 10.99 specification for Lithium-ion traction battery packs and systems Part 3: Safety performance requirements ISO/NP PAS 16898 Electrically propelled road vehicles 10.99 Battery system design Requirements on dimensions for lithiumion cells for vehicle propulsion ISO/CD 23274-1 Hybrid-electric road vehicles Exhaust 30.20 emissions and fuel consumption measurements Part 1: Nonexternally chargeable vehicles ISO/DIS 23274-2 Hybrid-electric road vehicles Exhaust 40.20 emissions and fuel consumption measurements Part 2: Externally chargeable vehicles B. Standards and projects under the direct responsibility of IEC TC69 TABLE VII STANDARDS/ PROJECTS PUBLISHED BY IEC TC69 Reference, Edition, Date, Title IEC/TR 60783 Edition 1.0 (1984-12-30) Wiring and connectors for electric road vehicles Stability Date : 2008 IEC/TR 60784 Edition 1.0 (1984-12-30) Instrumentation for electric road vehicles Stability Date : 2008 IEC/TR 60785 Edition 1.0 (1984-12-30) Rotating machines for electric road vehicles Stability Date : 2008 IEC/TR 60786 Edition 1.0 (1984-12-30) Controllers for electric road vehicles Stability Date : 2008 IEC 61851-1 Edition 2.0 (2010-11-25) Electric vehicle conductive charging system - Part 1: General requirements Stability Date : 2012 IEC 61851-21 Edition 1.0 (2001-05-04) Electric vehicle conductive charging system - Part 21: Electric vehicle requirements for conductive connection to an a.c./d.c. supply Stability Date : 2010 IEC 61851-22 Edition 1.0 (2001-05-04) Electric vehicle conductive charging system - Part 22: AC electric vehicle charging station Stability Date : 2010 IEC 62576 Edition 1.0 (2009-08-18) Electric double-layer capacitors for use in hybrid electric vehicles - Test methods for electrical characteristics Stability Date : 2014 TABLE VIII STANDARDS/PROJECTS UNDER DEVELOPMENT BY IEC TC69 Project Reference IEC 61851-21 Ed. 2.0 Review Report on IEC 61851-21 Ed. 1.0: Electric vehicle conductive charging system - Part 21: Electric vehicle requirements for conductive connection to an a.c./d.c. supply IEC 61851-22 Ed. 2.0 Electric vehicle conductive charging system - Part 22: a.c. electric vehicle charging station IEC 61851-23 Ed. 1.0 Electric vehicle conductive charging system - Part 2-3: D.C electric vehicle charging station IEC 61851-24 Ed. 1.0 Electric vehicles conductive charging system - Part 24: Control communication protocol between off-board d.c. charger and electric vehicle IEC 61980-1 Ed. 1.0 Electric equipment for the supply of energy to electric road vehicles using an inductive coupling - Part 1: General requirements IEC 61980-2 Ed. 1.0 Electric equipment for the supply of energy to electric road vehicles using an inductive coupling - Part 2: Manual connection system using a paddle IEC 61981 Ed. 1.0 On board electric power equipment for electric road vehicles ISO/IEC 15118-1 Ed. 1.0 Road vehicles - Vehicle to grid communication interface - Part 1: General information and use-case definition 60069-182 Ed. 1.0 Electric vehicle charging and discharging metering and billing equipment 69-176 Ed. 1.0 Utility grid communication network in electric vehicle charging infrastructure 69-177 Ed. 1.0 IEC 61851-2-x: Electric vehicle conductive charging system - Part 2-x: Control communication protocol between a.c./d.c. supply hybrid charging system and electric vehicle 69-181 Ed. 1.0 Electric charging station - Charging supervisor system 69-183 Ed. 1.0 General technical requirements for off-board charging and discharging equipment 69-1 Ed. 1.0 Electric vehicle conductive charging system - Part 24: Communication protocol between off-board charger and electric vehicle 69-2 Ed. 1.0 Battery exchange infrastructure Stage 1CD (1st Committee Draft) 1CD 1CD ANW (Approved New Work) (Proposed New Work) (Potential new work item) 2CD (2nd Committee Draft) The standards and projects under the direct responsibility of IEC TC69 [11] already published are shown in Table VII

and Table VIII, this later with the stage codes. It should be noticed, that even though the stages and associated documents have in most cases similar codes and names for both ISO and IEC (cf. Table III, Table V, Table VI and Table VIII), they are not always exactly the same. A full list of IEC stage codes (as those in Table VIII), its meaning and the equivalent harmonized stage codes can be found in [12]. C. ISO/IEC Directives, Procedures for the technical work As said previously, to avoid conflicts and overlaps between ISO and IEC standards a consensus agreement and an ISO/IEC Memorandum of Understanding (MoU) were done. Also, to overcome the issues raised by different procedures of each organization, ISO/IEC Directives were established to standardize common standardization activities (cf. Table II): ISO/IEC Directives, Part 1: Procedures for the technical work [13]; ISO/IEC Directives, Part 2: Rules for the structure and drafting of International Standards [14]; ISO Supplement, Procedures specific to ISO [15]; For example, the ISO/IEC Directives, Part 1, shows the project stages and associated documents as to be used by the both organizations and joint working groups, as in Table IX. TABLE IX PROJECT STAGES AND DOCUMENTS FOR ISO/IEC [13] Project stage Associated document Name Abbreviation Preliminary stage Preliminary work item Proposal stage New work item proposal 1) NP Preparatory stage Working draft(s) 1) WD Committee stage Committee draft(s) 1) CD Enquiry stage Enquiry draft 2) ISO/DIS IEC/CDV Approval stage final draft International FDIS Standard 3) Publication stage International Standard ISO, IEC or ISO/IEC 1) These stages may be omitted, as described in Annex F of [13] 2) Draft International Standard in ISO, committee draft for vote in IEC. 3) May be omitted (see 2.6.4 of [13]). As all these stages and process can seen a little bit fuzzy, a flowchart showing the process for the development of new standards and the maintenance of existing standards and another with the overview of the processes for the withdrawal and the systematic review of existing standards can be found in the ISO Supplement [15]. D. Standardisation Mandate to CEN, CENELEC and ETSI Concerning the Charging of Electric Vehicles IEC and ISO have published or started to develop the previously mentioned standards. However, there are some difficulties on ensuring interoperability between chargers of EVs, as, for example, at IEC level there are at least three different types of plugs under consideration (IEC 62196-2, Table II), and different power levels (charge modes) previewed (IEC 61851-1, Table VII) [16]. A freely available short explanation on this subject can be found in [17]. This lack of interoperability would fragment the market, creating difficulties to the EVs mobility between regions and states. Being aware of this, in June 2010 the European Commission, EC, by the Mandate M/468, has requested the CEN, the CENELEC and the ETSI (European Telecommunications Standards Institute) to develop European standards or to review existing standards in order to: a) Ensure interoperability and connectivity between the electricity supply point and the charger of electric vehicles, including the charger of their removable batteries, so that this charger can be connected and be interoperable in all EU States. b) Ensure interoperability and connectivity between the charger of electric vehicle- if the charger is not on board- and the electric vehicle and its removable battery, so that a charger can be connected, can be interoperable and re-charge all types of electric vehicles and their batteries. c) Appropriately consider any smart-charging issue with respect to the charging of electric vehicles. d) Appropriately consider safety risks and electromagnetic compatibility of the charger of electric vehicles in the field of Directive 2006/95/EC (LVD) and Directive 2004/108/EC (EMC). [18] As a consequence of this mandate, the Focus Group on European Electro-Mobility has been created and a Final Report to CEN and CENELEC Technical Boards in response to Commission Mandate M/468 concerning the charging of electric vehicles is expected by the end of June 2011. IV. EVS STANDARDIZATION ACTIVITIES IN PORTUGAL Due to the intense standards development activities presented before for EVs, also APVE and its two TCs [19], CTE 69 Electric Road Vehicles, and CT146 Electric Systems for Electric Road Vehicles, have been very active, especially during the last two years, as these TCs participate on that do IEC/ISO and CEN/CENELEC standards development process, having at least to review and comment the standards on its different stages, and to give advice to the IPQ vote for the Portuguese position. Furthermore, in order to help the Portuguese entities concerned with the EVs, APVE with CTE69 and CT146 is preparing the translation to Portuguese of the standards presented in Table X. TABLE X STANDARDS TO BE TRANSLATED TO PORTUGUESE Standards EN 1986-2:2001: Electrically propelled road vehicles - Measurement of energy performances - Part 2: Thermal electric hybrid vehicles EN 61851-21:2002 : Electric vehicle conductive charging system Part 21: Electric vehicle requirements for conductive connection to an a.c/d.c. supply EN 61851-22:2002: Electric vehicle conductive charging system - Part 22: AC electric vehicle charging station ISO 6469-1:2009: Electric road vehicles Safety specifications -Part 1: On-board electrical energy storage ISO 6469-2:2009: Electric road vehicles Safety specifications - Part 2: Functional safety means and protection against failures ISO 6469-3:2009: Electric road vehicles Safety specifications - Part 3: Protection of persons against electric hazards ISO 8713:2005: Electric road vehicles Vocabulary ISO 8714:2002: Reference energy consumption and range - Test procedures for passenger cars and light commercial vehicles ISO 8715:2001: Road operating characteristics ISO 23273-1:2006: Fuel cell road vehicles - Safety specifications Part 1: Vehicle functional safety ISO 23273-2:2006: Fuel cell road vehicles - safety specifications Part 2: Protection against hydrogen hazards for vehicles fuelled with compressed hydrogen

ISO 23273-3:2006: Fuel cell road vehicles - Safety specifications Part 3: Protection of persons against electric shock ISO 23274:2007: Exhaust emissions and fuel consumption measurements Non-externally chargeable vehicles ISO 23828:2008: Energy consumption measurement - Vehicles fuelled with compressed hydrogen V. CONCLUSIONS Before concluding, it is important to clarify the differences between Standards and Regulations. Standards are voluntary documents produced by technical committees and approved by the representatives of the concerned and interested entities in the countries (namely the IEC National Committees or ISO national standards institutes). On the other hand, regulations are legally binding documents, which are issued by government. Nevertheless, our modern way of life would not be possible without standards (and many standards finally are adopted has regulation by the countries). From an electrical point of view, it suffices to think what would happen if we had several different plugs in each country, with different voltage levels and frequencies! The same happens with the EVs, and at this stage of the first wave of modern EVs reaching the market, there are many aspects of EVs that still can and need to be standardized as, for example, the plugs for charging, the chargers voltages, the communication between the vehicle and the chargers, fast charging systems and respective billing, security measures for vehicle safety and safety of persons against electric shock, electromagnetic compatibility and health effects issues [20], on-board electric energy storage for propulsion and vehicle energy performance and energy measurements. The evolution of electric vehicle standardization, from the very beginning, was the subject of an important doctoral thesis on this subject, The Electric Vehicle: Raising the Standards, from the actual IEC TC69 Secretary, Prof. Peter Van den Bossche [21]. Nowadays there is still an intense effort on this subject endured by different standardization organizations and also by European Commission. In this paper, the EV standardization framework was presented on a compact form as well as the most important standardization activities going on at world, Europe and Portugal levels. References were given allowing the non standards expert, to easily and quickly access the state of the standardization activities in the EVs frameworks also in the future. The Standardization in Electric Vehicles is not an easy task. But a serious amount of effort is being put on this in order to ensure that there are no obstacles from this point of view to the EVs massive spread as a sustainable mobility solution. VI. REFERENCES [1] P.G. Pereirinha, J.C. Quadrado, J. Esteves, Sustainable Mobility: Part I Main Problems, Proceedings of the CEE'05 - International Conference on Electrical Engineering - 10-12 October 2005, Coimbra Portugal, in CD-ROM. [2] P.G. Pereirinha, J.C. Quadrado, J. Esteves, Sustainable Mobility: Part II Some Possible Solutions Using Electric and Hybrid Vehicles, Proceedings of the CEE'05 - International Conference on Electrical Engineering - 10-12 October 2005, Coimbra Portugal, in CD-ROM. [3] International Electrotechnical Commission (IEC) web-site, www.iec.ch [4] International Organization for Standardization (ISO), www.iso.org [5] Peter Van den Bossche, Joeri Van Mierlo, Yonghua Cheng, Jean Timmermans, Evolution of international standardization of electrically propelled vehicles, Proc. of the European Ele-Drive Transportation Conference 2007, EET-2007, 30th May - 1st June 2007, Brussels, Belgium, in CD-ROM. [6] ISO shapes future of electric vehicles, Press Release, 2011-02-17, www.iso.org/iso/pressrelease.htm?refid=ref1402 [7] ISO/IEC Agreement Concerning Standardization of Electrotechnology for Road Vehicles and the Cooperation Between ISO/TC 22 Road Vehicles and IEC Technical Committees, 2010. [8] Stages of the development of International Standards, ISO, www.iso.org/iso/standards_development/processes_and_procedures/ stages_description.htm [9] International harmonized stage codes, ISO, www.iso.org/iso/standards_development/processes_and_procedures/ stages_description/stages_table.htm [10] ISO, Standards and projects under the direct responsibility of the Secretariat of TC 22/SC 21 - Electrically propelled road vehicles, www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_tc_browse. htm?commid=46946 [11] IEC - TC 69, Electric road vehicles and electric industrial trucks, Projects / Publications, www.iec.ch/dyn/www/f?p=103:23:0::::fsp_ ORG_ID,FSP_LANG_ID:1255,25 [12] Stage s, IEC, www.iec.ch/standardsdev/how/processes/stage_ codes.htm [13] ISO/IEC Directives, Part 1: Procedures for the technical work (8th edition, 2011). [14] ISO/IEC Directives, Part 2: Rules for the structure and drafting of International Standards (6th edition, 2011). [15] ISO Supplement, Procedures specific to ISO (2nd edition, 2011); [16] Plug them in and move them on!, IEC e-tech, April 2011, www.iec.ch/etech/2011/etech_0411/tc-1.htm [17] IEC 62196, http://en.wikipedia.org/wiki/iec_62196 [18] M/468 EN, Standardisation Mandate to CEN, CENELEC and ETSI Concerning the Charging of Electric Vehicles, European Commission, Brussels, 4th June 2010, http://ec.europa.eu/energy/ gas_electricity/smartgrids/doc/2010_06_04_mandate_m468_en.pdf [19] Normalização, Associação Portuguesa do Veículo Eléctrico, www.apve.pt/content01.asp?treeid=06 [20] International Commission on Non-Ionizing Radiation Protection, Guidelines for Limiting Exposure to Time-Varying Electric and Magnetic Fields (1 Hz to 100 khz), ICNIRP Guidelines, Health Physics, December 2010 Vol. 99 - Issue 6 - pp 818-836. [21] P. Van den Bossche, The electric vehicle: raising the standards, PhD thesis, Vrije Universiteit Brussel, 2003.