LCVTP WS1 Battery & Battery Packs Workstream members John Lewis, Tony Smith, Robinson Stonely, Mark Tucker, Gary Kirkpatrick, Stene Charmer, Salvio Chacko & Valerie Self Jeremy Greenwood & Kotub Uddin Mark Amor-Segan & Yue Guo Robert Ball James Marco & Cip Antaloae TMETC JLR WMG Ricardo Cranfield Presented by Valerie Self Tata Motors WS1 Lead
Summary Workstream Goal and Structure Task Responsibilities Summary of WS1 Tasks Conclusions Questions
Workstream Goal & Structure Workstream Goal To develop modules suitable for battery packs for GTVs Source and validate suitable cells and the hardware and software for associated BMS Develop processes & methodologies to support workstream goals Workstream Structure Divided into nine sub-tasks Each task has set of deliverables Task deliverables have interdependencies
Workstream Structure Task 1.1 Validate Cell Claims Task 1.9 Packaging Task 1.2 Modelling Task 1.3 Testing Task 1.5 Integration Task 1.7 Long term targets Battery Management System Task 1.8 Recycling issues Task 1.4 BMS design Task 1.6 BMS algorithms
Task Responsibilities JLR Tata Ricardo WMG Cranfield S L S S S Validate Cell Claims S S S L L Battery Modelling S S S L S Characterisation & Accelerated Life Testing L S S S S Validate BMS System Design S L L S S Pack Integration L L S S S Develop Suitable BMS Algorithms & Hardware S S L S S Longer Term Targets for Next Generation Technologies S S S L S Recycling Issues L = Leader of Task S = In Support S L S S S Module & Pack Concept Design
Task 1.1- Database of Li-ion Cells Suppliers Based on manufacturer s data for 860 cells Wide range of cells included (not just EV traction cells) Includes original datasheets Allows initial comparison of claimed performance, prior to more rigorous testing
Task 1.1- Report on Abuse Testing Methodology Report allowing the initial comparison of abuse test types Further work to establish WS testing methods
Task 1.2 - Battery Modelling Determine model requirements - Select model architecture & tools - Cell equivalent electrical circuit model Dymola chosen as modelling tool Cell model - Literature review completed Model is completed and parameterised against A123, EIG & Dow Kokam cells Pack model - Takes into account design parameters, manufacturing tolerances, interconnect impedances, cell chemistries, calendar age and life cycle to allow predictions to be made.
Task 1.3 - Battery Testing Initial Cell characterisation testing Final Cell characterisation and project specific testing Cells chosen for module Pulse Power Tests Charge Retention Test OCV vs. SoC Test Cell Expansion Test Thermal Characterisation Test Storage Life Test Energy Efficiency Test Agreement on Real World Accelerated Life Testing Protocol Methodology is defined, IEC 62660-1 Cycle life testing will be run continuously
Task 1.3 - Battery Testing University of Warwick Li-ion testing facility Battery cell cycler: Bitrode MCV16-100-5 x 2 Environmental Chamber: Weiss Gallenkamp Votsch VC3 4060 x 2 High Temperature Battery Storage Chamber: Weiss Gallenkamp Votsch VT3050 Multi-channel temperature measurement system Thermal Imaging Cameras FLIR T425 x 2 AC spectrum impedance tester Weld Testing Cell Expansion Testing
Task 1.4 - Validate BMS System Design 1 Current In 1 Cell s1 Slave 1 Estimated SOC Energy etc Master Cell s2 Cell sn Initial Requirements Specification for BMS Generic requirements developed within WS1 Slave 2 Slave n BMS Concept FMEA Developed by TMETC, JLR, Ricardo and WMG in association with hardware and battery integration suppliers BMS Test Specification Used to assess WS1 BMS hardware capabilities Initial Functional Safety Developed by TMETC & JLR to work towards an ISO26262 compliant system Assessment BMS Test Report Report demonstrating the capability of the BMS hardware, software and algorithms
Task 1.5 - Module Specification Specification document that derives the characteristics of the desired module from a consideration of GTV applications and the shortlisted cells. The specification covers electrical, physical, thermal and environmental characteristics of the module, together with safety features and the BMS.
Task 1.5 - Patent Report on Module & Interconnect Design Completed Espacenet searches by Keywords or Applicant- then filtered down to 223 relevant results Output was presented in a very useable format as a Mindmap, covering interconnects, cell, module and pack design.
Task 1.5- FE Analysis of Module CAD Design Finite Element analysis of the 48-cell module for static and dynamic loadings- both during module construction and during vehicle service. Loads transferred to individual cells were modelled. Peak cell acceleration 300g over 3ms. Highest accel seen on RH side as closing velocity increases with rotation Drop 100mm at 50 Module deforming during simulated 100mm drop test
Task 1.5 - Distribution of Modules Report has considered the options for distributed packs Series vs. parallel modules Switching, fusing, interconnection options Compliance with standards, cell manufacturers recommendations, reliability, cost, weight.. ECE/TRANS/WP.29/2010/52 SAE J2289 SAE J2344 Report concludes series connection lower risk
Task 1.5- Interconnect Testing Interconnect materials have been chosen to represent the chosen cell and interconnect geometry 160 samples have been joined using ebeam and ultrasonic welding, soldering, clinching and gluing on different tab materials Testing has shown no overall best joining solution Some techniques (ultrasonic welding, clamping) showed lack of maturity in process settings and would need to be optimised for a specific tab application Some (gluing, soldering) had more inherent difficulties in application
1.5 Thermal Management Strategy Maintain cell temperature at around 20 C to ensure safety, performance and life Requirements influenced by cell choice, vehicle operating environment and duty cycle A flexible and scalable module should be capable of accommodating a number of thermal management solutions to optimise system efficiencies (energy, mass, volume, cost) Thermal management elements Inter-cell Phase Change Material (PCM) Inter-cell Heat Transfer Plate Inter-cell Active Cooling Plate Module base / side plate with Active Cooling Initial module is designed around a 2C maximum discharge rate (EV) Analysis to determine requirements for 4C and 10C applications Inter-cell active cooling plates Inter-cell HT plates + PCM + active base plate Inter-cell HT plates + active base plate PCM No cooling 1 2 4 Maximum Discharge Rate [C] 10+ Thermal Pack Model Simulation TMETC have developed a Li-Ion pouch cell electro thermal 3D CAE model It allows engineers to simulate heat generation as a function of electrical discharge/soc It is an insightful design tool, facilitating the virtual evaluation and development of battery thermal management systems prior to sourcing hardware/test
Task 1.6 Develop BMS Algorithms/Hardware Hardware for Master & Slave and associated embedded software with integrated SOC estimation File: A10_NEDCx3_41%SOC_020610_log3 20 3.7 10 Load Current - [A] Terminal Voltage - [V] State-of-Charge Comparison: Commercial BMS v EKF 3.75 3.65 3.6 3.55 3.5 0 1000 2000 3000-20 0 1000 2000 3000 4000 50 State-of-Charge - [%] Temperature - [oc] -10-30 4000 25.8 25.6 25.4 25.2 25 0 0 1000 2000 3000 4000 Commercial BMS EKF 45 40 35 30 25 0 1000 2000 3000 4000 Graph shows a cell being discharged The WS1-developed BMS is shown to give a more realistic step change and is far less noisy than the commercial BMS
Task 1.7- Long-Term Targets & Next Generation Technologies & 1.8 Recycling Issues 1.7 Long Term Targets Report analysing the likely OEM demand for EV batteries by 2020, and the required changes in battery capacity, power, weight, lifetime and recycling needs 1.7 Next Generation Technologies Forward-looking report covering the likely developments in traction batteries by 2020 1.8 Battery Recycling Issues Report showing potential range of 2nd life usages adding value for vehicle OEM battery packs. Report highlights barriers to be addressed and issues with battery cell recycling
Task 1.9 Tata & JLR GTV Battery Concept Packaging Tata Battery Concept Packaging Battery packaged centrally under floor EV Target = 25.5 kwh, 320V Nominal WS1 Module Solution: > 3x 10S4P modules + > 3x 22S4P modules Total Pack: 96S4P (25.3 kwh, 317V Nominal) Battery packaged under floor together with APU fuel tank RE-EV Target = 12.75 kwh, 320V Nominal WS1 Module Solution: > 5x 20S2P modules Total Pack: 100S2P (13.2 kwh, 330V Nominal) JLR Battery concept Packaging Target = 12kWh useable Target = 360V Use 475.2V (144s1p)
Task 1.9 Concept Module Hardware build requirements Mini modules (2P, 3S) for abuse testing Thermal shock Thermal runaway Propagation Spare 1 1 1 1 Full modules (2P, 12S) for dynamic testing Mechanical shock 3 Vibration 1 Demonstration unit 1 (Note: Demonstration unit is a fully functioning battery module complete with wiring harness)
Conclusions Modelling Initial cell and pack models have been created to simulate performance which are suitable for further development Testing Results from comprehensive cell testing will provide valuable information on comparative performance for range of cells Performance and abuse testing Battery Management System Initial work on algorithms, hardware and software for a cell agnostic battery management system has been completed which is suitable for further development Module Phase 1 design and feasibility of the module concept has been delivered This will provide flexible design to meet pack requirements of JLR and Tata GTV s
Questions Thank You Any Questions?