Deliverable 9.8 Report on Mobile Battery Test Platform and Results Of
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Deliverable 9.8 Report on mobile battery test platform and results of the measurements Prepared by: Kim Winther, DTI [email protected] Morten Holst, DTI [email protected] Date: December 18th, 2014 Version: 4.1 GA MOVE/FP7/265499/Green eMotion WP 9: Deliverable 9.8 Page 1 of 55 Document Information Authors Name Company Key author Kim Winther DTI Further authors Morten Holst DTI Distribution Dissemination level PU Public x PP Restricted to other programme participants (including the Commission Services) RE Restricted to a group specified by the consortium (including the Commission Services) CO Confidential, only for members of the consortium (including the Commission Services) Revision history Version Date Author Description 1.0 August 8th, 2014 Kim Winther Initial version 2.0 November 12th, 2014 Morten Holst Thorough draft 3.0 November 26th, 2014 Morten Holst Final version 4.0 December 17th, 2014 Luis de Prada External Review 4.1 December 18th 2014 Kim Winther For Approval Status For Information Draft Version Final Version (Internal document) Submission for Approval (deliverable) X Final Version (deliverable, approved on) GA MOVE/FP7/265499/Green eMotion WP 9: Deliverable 9.8 Page 2 of 55 Table of Contents 1 Executive Summary .................................................................................................................. 7 2 Introduction ............................................................................................................................... 8 2.1 Purpose and background ................................................................................................................... 8 2.2 Important definitions ........................................................................................................................... 9 2.2.1 What is Capacity? ........................................................................................................................... 9 2.2.2 What is state of health? ................................................................................................................ 10 2.2.3 What is State of Charge? .............................................................................................................. 11 2.2.4 What is Impedance? ..................................................................................................................... 11 2.3 Battery types used in this project ..................................................................................................... 12 3 Battery performance evaluation .............................................................................................. 13 3.1 Mobile test platform .......................................................................................................................... 13 3.1.1 Electro Impedance Spectrography ............................................................................................... 16 3.1.2 CAN communication ..................................................................................................................... 17 3.1.3 Non-intrusive methods .................................................................................................................. 18 3.2 Discharging through DC fast charge connector ............................................................................... 18 3.2.1 Gaining access to the traction battery through DC fast charge connector ................................... 19 3.2.2 Designing a mobile load bank ....................................................................................................... 19 3.2.3 Quantifying the auxiliary consumption during capacity measurements........................................ 20 3.2.4 Automated internal resistance measurement ............................................................................... 20 3.3 Hardware and software implementation .......................................................................................... 22 3.3.1 Implementation of load bank and associated data acquisition equipment ................................... 22 3.3.2 Implementation of DC fast charge connector ............................................................................... 23 3.3.3 Improvements to increase EV usability ........................................................................................ 24 3.3.4 Pulse discharging during driving ................................................................................................... 24 3.3.5 C/3 discharging ............................................................................................................................. 25 3.3.6 Capacity vs. temperature .............................................................................................................. 26 3.3.7 Battery efficiency .......................................................................................................................... 27 3.4 Battery modelling ............................................................................................................................. 28 3.4.1 Equivalent circuit model ................................................................................................................ 28 3.4.2 Full performance sheet ................................................................................................................. 32 3.4.3 Power losses in battery model ...................................................................................................... 36 3.4.4 Nyquist plot ................................................................................................................................... 36 3.4.5 EVPC pulse sequence simulation ................................................................................................ 39 3.4.6 ISO 12405-2 simulation ................................................................................................................ 41 3.4.7 Randle coefficients vs. age of battery ........................................................................................... 44 3.5 Experiments versus model ............................................................................................................... 46 4 Conclusions ............................................................................................................................ 54 4.1 What can be learned about modelling ............................................................................................. 54 4.2 Why is vehicle power not affected by SOH ...................................................................................... 54 4.3 What are the implications of our findings for policy in general......................................................... 55 GA MOVE/FP7/265499/Green eMotion WP 9: Deliverable 9.8 Page 3 of 55 List of Figures Figure 2.2.1: Capacity and degradation explained 9 Figure 2.2.2 SOH indicator on a Nissan Leaf 10 Figure 2.2.3: Degradation data obtained from a fleet of Renault Zoe vehicles 11 Figure 2.2.4: Impedance explained 12 Figure 3.1.1: The mobile test platform delivered at DTI grounds in Aarhus, Denmark 13 Figure 3.1.2: The mobile test platform in action on proving grounds in Karup, Denmark 14 Figure 3.1.3: Mobile test platform in action on proving grounds in Værløse, Denmark 14 Figure 3.1.4: CAN communication as used in the CHAdeMO protocol 17 Figure 3.1.5: The SORDS drive cycle test scheme 18 Figure 3.2.1: The mobile load bank in action on parking lot in Aarhus, Denmark 20 Figure 3.2.2: Visualizing the load sequence 21 Figure 3.2.3: Example of measured pulse used to determine battery internal resistance, at 50% SOC 21 Figure 3.2.4: Example of measured battery discharge period, 100% to 90% SOC at 25A 22 Figure 3.3.1: Mobile load bank unit in the battery service vehicle 23 Figure 3.3.2: Retrofitted J1772, DC connector and pin-out 23 Figure 3.3.3: Upper cable conduits are retrofitted for DC connector 24 Figure 3.3.4: Non-intrusive field measurements of step response with Renault Fluence ZE 25 Figure 3.3.5: Energy capacity versus ambient temperature 26 Figure 3.3.6: Grid-to-road efficiencies for the EVs used in the on-road tests 27 Figure 3.4.1: 2nd order Randle circuit model 29 Figure 3.4.2: Illustration of the OCV volume model, “the bohemian floor vase” 30 Figure 3.4.3: Discharge performance shown in charge (Ampere-hours), illustrated by Renault Fluence ZE battery (25-02-2014, 7.5°C). 33 Figure 3.4.4: Discharge performance shown in energy, illustrated by Renault Fluence ZE battery (25-02- 2014, 7.5°C). 33 Figure 3.4.5: Discharge performance shown in charge (Ampere-hours), illustrated by Nissan Leaf battery (25-02-2014, 7.5°C). 34 Figure 3.4.6: Discharge performance shown in energy, illustrated by Nissan Leaf battery (25-02-2014, 7.5°C). 34 Figure 3.4.7: Reconstructed Nissan Leaf battery cell discharge characteristics 35 Figure 3.4.8: Nissan Leaf battery cell discharge characteristics 35 Figure 3.4.9: Nyquist plot of the Mitsubishi i-MiEV battery progressing over three years of time. 37 Figure 3.4.10: Nyquist plot of the Nissan Leaf battery short term progress. The vehicle was new (mileage: 50 km). 37 Figure 3.4.11: Nyquist plot of the Nissan Leaf battery short term progress. The 2014 Nissan Leaf was more experienced (mileage: 3,300 km) than the 2013 one. 38 Figure 3.4.12: Nyquist plot of two different Renault Fluence ZE batteries. 38 Figure 3.4.13: Input battery current and modelled voltage waveforms, illustrated by the Mitsubishi i-MiEV 39 Figure 3.4.14: