LCVTP WS1 Battery & Battery Packs

Transcription

1 LCVTP WS1 Battery & Battery Packs Workstream members Mark Amor-Segan & Yue Guo Jeremy Greenwood, Kotub Uddin Nigel Taylor, Khoon Meng Tan Robert Ball & Julian Dunn James Marco & Cip Antaloae Gary Kirkpatrick, Robinson Stonely, Tony Smith, Stene Charmer, Salvio Chacko, Mark Tucker, John Lewis & Valerie Self WMG JLR Ricardo Cranfield TMETC Presented by Valerie Self WS1 Lead

2 Summary Workstream goal and structure Task responsibilities Summary of status current tasks Conclusion

3 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

4 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

5 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 L L S S S Module & Pack Concept Design

6 WP1.1 Cell Selection Vehicle / Battery System Targets JLR and Tata GTV vehicle performance and range simulation completed to enable cascade of requirements to battery system > Real world usage and legislated drive cycles > Performance over Battery State of Charge (SOC) window > Battery degradation over time Targets developed for energy, power, mass & volume Vehicle Requirements Vehicle Testing Vehicle Simulation Vehicle Level Verification Simulate Aggregate Level Targets Aggregate Level Verification Validate Design and Implementation

7 Energy Yield [%] WP1.1 Cell Selection Cell Selection Process Summary Lithium-Ion database developed (> 800 cells) Initial filtering to remove nonautomotive cells (< 35 cells) Pugh Chart Analysis to compare cell Relative Scoring for each Chemistry (best chemistry =10, remaining relative) chemistry and format 9 short listed cells exercised through selection of screening tests Li-Titanate (LTO) Li-Fe-Phosphate (LFP) Li-MnO (LMO) Ni-Maganese-Cobalt (NMC) Verification of manufacturers performance and capacity figures Testing at 0, 25, 45 deg C 3 cells chosen to complete full IEC performance testing & GTV module design Li-NiAlCo (NCA) Energy Yield at 25 C Safety Aging Servicability Durability (manufacturing quality) Cost Performance Packaging Thermal Management 90.0 Cell 1 Cell 2 Cell 3 Cell 4 Cell 5 Cell 6 Cell 7 Cell 8 Cell 9

8 Module Concept and Design (WP 1.1 & WP 1.9) Module concept and design underway for each of the 3 chosen cells Module must be flexible and scalable such that it is suitable for Tata and JLR GTV vehicles Competitor benchmarking / reference Benchmark Battery Tata GTV Vehicle Battery Package Space JLR GTV Vehicle Battery Package Space Benchmark Module

9 Task 1.2 Battery Modelling Module and pack level overview - Design parameters - Manufacturing tolerances - Active/Passive balancing - Interconnect impedances - Chemistries - Calendar age - Cycle life Getting the required data into model - Matlab 4(.mat) files - Comma separated values files (.csv) Real-time performance and scalability

10 Battery Modelling Equivalent cell circuit model

11 Task 1.3 Battery Testing Battery cell received Testing methodology - IEC (Annex A): Secondary lithium-ion cells for the propulsion of electric road vehicles - Additional tests: Continues power tests, AC spectrum impedance testing Testing Progress - Initial test (NCM) - Completed at UoG - Short-listing tests - Completed at UoG - Additional tests underway

12 Battery Testing New Li-ion testing facility - Battery cell cycler with Environmental Chamber - High Temperature Battery Storage Chamber - Multi-channel temperature measurement system - Thermal Imaging Cameras - AC spectrum impedance tester

13 Tasks 1.4 &1.6 BMS Objectives Report battery status > Instantaneous data e.g. state-of-charge, state-of-health, > Short term high resolution data e.g. diagnostic data > Long term low resolution data e.g. for warranty purposes Safety and protection of the battery/vehicle e.g. control of main and precharge contactors Maximise the energy that can be extracted from a battery pack whilst maintaining the cells voltages within predefined limits (outside of which cell damage or safety hazard may occur) e.g. balancing

14 BMS System Design Battery management hardware- JLR > Temperature, voltage and current measurement > Balancing circuitry Battery management algorithms TMETC > State-of-charge and state-of-health estimation > Balancing control 1 Current In Cells1 Slave 1 Master 1 Estimated SOC Energy etc Cells2 Slave 2 Cellsn Slave n

15 Balancing Considerations Cell imbalance caused by cells of different capacities, state-of-charge or internal resistance Effect of cell imbalance > Early charge termination - energy stored is less than capacity > Early discharge termination - energy used is less than available Balancing Solutions > Charge shunting - charging current by-passes a cell > Passive balancing - dissipate energy from highly charged cells > Active balancing - redistribute energy between cells

16 Algorithm Design Extended Kalman filter state-of-charge estimator per cell defined, comprising: > Corrector > Predictor that includes an internal cell model Equivalent electrical circuit model (simple low parameter model is suitable for automotive ECU with processing /memory constraints) Equivalent electrical circuit model equations derived and algorithms developed to extract parameters from open circuit voltage, pulse and discharge test data Equivalent electrical circuit model ready to be incorporated into Extended Kalman Filter

17 Task 1.5 Patent Search- interconnects and cell support Espacenet searches carried out by Keywords or Applicant - then manually filtered down to 223 relevant results Re-presented these results in a more useable format as a Mindmap, covering interconnects, cell, module and pack design (relevant to WS1 tasks).

18 Pouch Cell Support Structure Two approaches to determining strength required in cell support structures (pouch cell example shown here): No exact FE data exists for pouch cells (complex - Finite Element Analysis structure, solid & semisolid elements, behaves differently at different temperatures and SOCs) - Mechanical testing (vibration, shock loads) of prototype structure Aimed at answering the questions: - how strong does the support structure need to be? - will it still work with cells mounted horizontally or obliquely? - how does it cope with stresses from cell expansion?

19 Cell Interconnect Test pieces Test Sequences comprising some of: Electrical resistance test Microsection X-Ray Vibration Thermal Shock Exposure to automotive fluids Destructive pull Test Test Piece Design Joined area Test assemblies are made up of combinations of two parts: Part 1 Aluminium Foil (Nickel plated) Part 2 Copper Foil (Nickel plated) Combinations to be tested are Al/Al, Al/Cu and Cu/Cu Laser welding, ultrasonic welding, and clinching chosen as potential lowcost, high reliability joining methods

20 Thermal Simulation Of Cells Method Proposal Step 1 Cell electro thermal characterisation tests Record Current and Temperature Characteristics Step 2 - Parameterise cell data into a 3D cell level model that can predict thermal characteristics as a function of current Step 3 - Build 3D module level model using 3D cell level model apply thermal conduction paths and convection paths Step 5 - Parameterise 3D module model for 1D simulation here we will assess a means to extract 3D data into a 1D model assessing Lumped mass with conduction/convection paths Foster Network model may require broader 3D simulation runs Step 4 - Assess thermal management concepts Using the 3D module level model 3 Packs ~ 3 thermal concepts 2 drive cycles Step 6 provide Link For vehicle level simulation

21 Thermal Simulation Of Cells Method Evaluation Status Electro thermal parameterization tests for a 20Ah Pouch cell have been conducted. Data set used for initial model assessment. Electro thermal parameterization methods have been researched and the following techniques have been identified for evaluation Potential & current distribution in electro chemical cells, John Newman & William Tiedeman, Johnson Controls Modelling for the scaling-up of a lithium ion polymer battery Ui Seong Kima, Chee Burm Shina, Chi-Su Kimb, Ajou University, Kim, Shin and Kim (Journal of Power Sources ), Calculates cell heat flux/temperature based on current density in XYZ The team have completed evaluation of the method above, figures below present results from these initial simulations The graphs present test data and CAE predictions of single cell current, voltage and averaged cell surface temperature during a transient discharge and charge cycle, high correlation with the test data was achieved This figure presents the predicted surface temperature of the cell, the temperature field closely represented that recorded during the test

22 Thermal Simulation Of Cells - Next Steps Three cells have been identified for in depth evaluation, two cells from each batch will be subjected to electro thermal characterisation tests in a thermally controlled environment, characterisation tests include Two cells from each batch fully thermo coupled with ~ 16 thermo couples each (T type) The cells will be tested in parallel in a thermally controlled chamber The cells will be subjected to constant and transient charge and discharge rates The tests will be repeated for a broad range of ambient temperatures Data from these tests will then be used to construct electro thermal CAE models for each cell Team are currently evaluating module level thermal management systems using lumped mass heat dissipation. It is envisaged that following completion of the single cell tests that these simulations will be performed using electro thermal model, here simulations can be conducted inline with vehicle level discharge rates

23 Conclusions Deliverables completed > Database of Li-ion suppliers & Pugh Chart analysis of cell chemistries and cell type > Initial performance tests to assist with cell selection > Final choice of cells for full evaluation > CAD packaging analysis to confirm cell selection > Review of abuse test standards and test identification > Initial cell level model including first parameterisation Other deliverables for all tasks are in progress Demonstration modules for target GTVs key deliverable

24 Thank you