L11: Batteries Mechanical and Electrical Layouts

Transcription

1 L11: Batteries Mechanical and Electrical Layouts L11: 16-APR-2019 Outlook Modules and modularity Electric connections Ø18L650 battery back Web tutorials Cells and technologies Cylindrical, prismatic, Pouch heat flow in cell Packs, Banks and packing topologies Cooling integration Battery pack design Lund University / LTH / IEA / AR / MVKF25 /

2 Electric connection of cells Series [V] parallel [Ah] connections Connection busbars and cables are for electric distribution but also part of heat generation and distribution Nickel plate + spot welding = healthy low resistance connections Soldering, mechanical bolted connections, Lund University / LTH / IEA / AR / MVKF25 / s11p 51.8V18.7Ah com/watch?v=8xv8b 93EoH0 Patreon Reusing batteries <1A (2-4 peak) Series path of paralleled pairs Soldered connections 2x2.5mm 2 bus bars, 0.14mm 2 fuse wire connections Lund University / LTH / IEA / AR / MVKF25 /

3 4s30p 16.6V80Ah m/watch?v=ngp7cgby OLc&t=203s Reusage, sorting, 15x8 Cell holders & domains of parallel cells Net of spot welded Nistripes (0.15 mm thick) Lund University / LTH / IEA / AR / MVKF25 / s6p 48V20Ah m/watch?v=xoc4liy5sn I Ebikeschool New batteries, sorted Hexagon fitted and glued cells Series connected stack of paralleled cells spot welded and soldered NI-stripes Lund University / LTH / IEA / AR / MVKF25 /

4 18650 Li-ion Standard (size) cylindrical Li-ion cells ø18h65mm? Nortvolt Lingonberry NV INR21/70 E1 vs P1 Lund University / LTH / IEA / AR / MVKF25 / Xiaoyu Li et. Al A comparative study of sorting methods for Lithium-ion batteries, ITEC Asia-Pacific, 2015 Sorting methods Sorting methods Capacity and AC internal resistance (C+ACIR) Electrochemical impedance spectroscopy (EIS) Voltage curve Cell dynamic parameters Cell thermal behaviour Dynamic parameters are in interest but improved SOC aging need to be studied before producing B-pack Lund University / LTH / IEA / AR / MVKF25 /

5 Nickel connection strips, BMS Lund University / LTH / IEA / AR / MVKF25 / BPD:intro Overview: BatPackDes Battery Pack Design Mechanical and electrical layout Purpose, function, model Geometry, cell, module, pack Batteries thermal modeling Cell design and thermal loads Cooling integration Battery management Control and management (SOC) Usage and degradation (SOH) Lund University / LTH / IEA / AR / MVKF25 /

6 BPD:intro Goals Design and dimensioning of battery pack based on suitable models evaluate suitable battery technologies, specify cell and packing, electric and thermal termination battery development and energy management systems, predict state of charge, health, function,.. testbattery compatibility to operating conditions, current waveforms Ageing model Thermal model Electrical model Lund University / LTH / IEA / AR / MVKF25 / BPD:intro Background A Vehicular application Electrification improves energy usage hybrids use ICE at 35% instead of 10-20% efficiency Reuse deceleration energy for acceleration Pure renewable fuel/energy System view Charging, static vs dynamic Compatability, AC current loading Battery and Propulsion Lund University / LTH / IEA / AR / MVKF25 /

7 BPD:intro Background C M. Yilmaz P.T.Krein 2013 Machine PE Battery cell Peak power density (kw/l) Peak specific power (kw/kg) Lund University / LTH / IEA / AR / MVKF25 / PART-1: BPD.EM Electrical and mechanical layout Function and realization Performance chart Characteristics and properties Models and tests Cell construction and design Cylindrical, prismatic, pouch design and realizations Pack specification Termination Modularity Lund University / LTH / IEA / AR / MVKF25 /

8 Lund University / LTH / IEA / AR / MVKF25 / B. Sarlioglu et al, Driving toward accessibility IEEE 2017 Comparison of vehicle battery types Lund University / LTH / IEA / AR / MVKF25 /

9 B. Sarlioglu et al, Driving toward accessibility IEEE 2017 Comparison of battery cell types Lund University / LTH / IEA / AR / MVKF25 / Overview of cell producers for xevs It is easier to find producer than product ;) Lund University / LTH / IEA / AR / MVKF25 /

10 Vehicular application Lund University / LTH / IEA / AR / MVKF25 / Energy storage for vehicular application Battery most important, currently most expensive Battery technology in its infancy, expectedly continues to mature, reducing price and size, increasing capacity 2010 the cost of an EV battery per kilowatt-hour (kwh) ranged from US$600 to US$1,105 (2010). Last five years has brought the estimated price near US$500/kWh. Vehicular requirement (apart from no cost): Range=energy capacity, Acceleration=Power Lund University / LTH / IEA / AR / MVKF25 /

11 Roadmap: from cell to pack Design path from topology sketching to practical realization Cell, Module, Pack/Bank Battery = Energy storage [Wh] & Power supply [W] Applications: Vehicle/Grid Technologies: Li-ion Battery cell Geometries and dimensions Characteristics and properties Cell virtual packing Electro-Thermal models Packing examples Thermal design Cells, modules, backs Battery Management System current voltage DoD Electrical model SoH Ageing model power temperature Thermal model Lund University / LTH / IEA / AR / MVKF25 / Battery back design & sizing Number of series connected cells in strings Ns=Udc/Ucell Number of parallel connected strings Np=Energy/(Ns*[Wh/kg]*[kg]) Np=Energy/(Ucell* cell capacity ) Circuits Electric, thermal, etc Protection, surge, over voltage and overheat Self study from page 161 example cell selection consequences 300 V * 100 A Pmax = 2*30kW P/E ratio 2 and 20 Lund University / LTH / IEA / AR / MVKF25 /

12 Cylindrical, Prismatic, Pouch Hundred or thousands of series and parallel coupled cells to achieve the required power and energy Joining requirements: electrode-to-tab + case container Anode Separator Cathode Lund University / LTH / IEA / AR / MVKF25 / Energy Management vs Design Information Energy Conversion Construction Production Energy Monitoring measure what is important Control keep it optimal and constrained Diagnosis keep battery cells healthy CELL Joining methods and E, M, T criteria? A cross-road of different disciplines Multi-dimensional (analysis) & multiobjective (synthesis) Pack specification System safety Pack architecture BMS design Electrical power system Pack design Electrical distribution system Module design Module CU Lund University / LTH / IEA / AR / MVKF25 / kg kw, kwh

13 Ragone plot Specific energy and power Specific energy originates from material chemistry Capacity capability Specific power is related to material physics and production Internal power losses and thermal constrains durability and safety Lund University / LTH / IEA / AR / MVKF25 / Fig.Ref.: B. Averill, P. Eldredge, General Chemistry: Principles, Patterns and Applications Value chain for EV batteries From cell realization to recycling (excluding raw materials) Vehicle power (performance), energy (range) and integration (BMS) Lund University / LTH / IEA / AR / MVKF25 /

14 R. Purkayastha, R.M. McMeeking, "A Linearized Model for Lithium Ion Batteries and Maps for their Performance and Lithium Battery Technologies Optimal performance and lifetime capacity Case sensitive: application vs cell configuration What is and can be done? Abbr Wh/kg Lithium cobalt oxide LiCoO 2 LCO Lithium manganese oxide LiMn LMO 4.0V Lithium iron phosphate LiFePO 4 LFP 3.2V Lithium nickel manganese cobalt oxide LiNiMnCo0 2 NMC 3.7V Lithium nickel manganese aluminum oxide LiNiCoAlO 2 NCA Lithium titanate Li 4 Ti 5 O 12 LTO Lund University / LTH / IEA / AR / MVKF25 / M. Yazdanpour, A circuit-based approach for electro-thermal modeling of Lithium-Ion batteries Cell material properties example material Thickness [μm] What dimensions what materials? Explore the rolled structure inside the battery cells in order to study loss generation and dissipation Thermal conductivity [W/mK] Electrical conductivity [S/m] + I collector aluminum e6 + Electrode (wet) 13.9 (wet) Electrolyte wet Separator (wet) - Electrode (wet) 100 (wet) - I collector copper e6 case Lund University / LTH / IEA / AR / MVKF25 /

15 Cell construction Electrode arrangement: spiral wound jelly roll, stacked electrodes, bobbin type Geometry: Cylindrical, Prismatic, Pouch, Button Components Case: plastic (PET) or metallic (steel, Al) Core=active components +collectors, separator Terminals Lund University / LTH / IEA / AR / MVKF25 / Prismatic Cells Some cell producers Hitachi, Samsung-SDI, Panasonic (Sanyo) Northvolt Cloudberry , Lingonberry NV INP27/91/148 L1 vs E1 PHEV2 format Prismatic p, c, L, [mm] W, [mm] T, [mm] M, [kg] U, [V] C,[Ah] cell [W/kg] [Wh/kg] Hitatchi SDI-1 37 SDI-2 60 SDI-3 94 Lund University / LTH / IEA / AR / MVKF25 /

16 Kokam.com Kokam s SLPB cell SLPB Superior Lithium Polymer Battery Pouch type improved heat dissipation due to larger surfaces Example 240Ah 4.8kg cell 480A Acool=2x0.15 m 2 V=46.2x32.7x1.58 cm specific energy, w cell [Wh/kg] Kokam large cells SLPB specific power, p cell [W/kg] Lund University / LTH / IEA / AR / MVKF25 / Specification list Forced heating/cooling for battery back Concepts, topologies, realization ideas, Battery cell Construction, properties, heat sources, thermal loads, Heat conductor Thermal accessibility, thermal contacts, Cooling plate Realisation, performance, Source Link Sink BPD:TH Lund University / LTH / IEA / AR / MVKF25 /

17 BPD:TH Thermal design CELL PACK SYSTEM Chemistry Geometry Properties Heat Thermal interface Cooling integration Electricity Methods, models, calculation examples for thermal design Practical realisation examples from some car manufacturers Lund University / LTH / IEA / AR / MVKF25 / Thermal modelling Models 1D, 2D, 3D analytic or numeric Computation time vs accuracy, Single cell, a module of cells, battery back Specification of equivalent cell volume with specific losses, Assembling, heat transport and temperature distribution Mechanical assembly and thermal accessibility, thermal contacts Integration of active cooling circuits Realisation, estimation of coolant flow and performance, Source Link Sink Lund University / LTH / IEA / AR / MVKF25 /

18 Lund University / LTH / IEA / AR / MVKF25 / Thermal integration Power semiconductor example Direct cooling where it is most needed in order to minimize heat transport through the solids that causes interior temperature rise and uneven temperature distribution Consider the effects of thermal cycling and expansion Experiences from other electric drive components Lund University / LTH / IEA / AR / MVKF25 /

19 Cooling integration Cooling mechanisms Cooling flow determination Cooling duct and system design From rough design point of view identify cooling surface and applied HTC on the surface Lund University / LTH / IEA / AR / MVKF25 / Cell library Connect geometry and power capability into battery-pack layout Selected cell examples: cylindrical, prismatic, pouch This information is used for virtual packing and rough estimation on temperature rise and distribution Manufacture configuration Geometry Voltage Capacity Specific r power Weight [mm] [V] [Ah] [W/kg] [g] Panasonic Cylindrical Ø18.5x Hitatchi Prismatic 148x91x Kokam Pouch 462x327x Lund University / LTH / IEA / AR / MVKF25 /

20 Cell virtual packing For 300V there is need of 84 series connected 3.6V cells First draft of 148x26.5 mm prismatic cell arrangement where 5 mm distance is left between the rows and groups of 7 cells First draft of ø18 mm 4 parallel cylindrical cell arrangement with cooling channel in between the cells Not only visualization but a parameterized model with coupling to finite element analysis (FEA) Lund University / LTH / IEA / AR / MVKF25 / Battery pack with cylindrical cells Empty space between cells Cross-flow through battery module Narrow spacing expectedly no cooling Large spacing for sake of better cooling is often considered impractical CFD vs fast design approaches Lund University / LTH / IEA / AR / MVKF25 /

21 Battery back with prismatic cells Temperature homogenization analysis Analysis of thermal runaway Lund University / LTH / IEA / AR / MVKF25 / Battery pack with pouch cells Coupled electro-thermal FE+model order reduction (MOR) simulation compared to thermographic images A reduced order model (ROM) based on singular value decomposition (SVD) Direct air-cooled Li-ion pouch battery cell in order to improve the understanding (modelling) and practical realization of battery module Lund University / LTH / IEA / AR / MVKF25 /

22 Chevy 104kW 20kWh GM Volt and Spark EV use thin prismatic shaped cooling plates in between the cells with the liquid coolant circulating thru the plate. The Volt cooling scheme is very effective from a cooling point of view but it is complicated. The cells are encased in multiple plastic frames Lund University / LTH / IEA / AR / MVKF25 / Tesla S 285kW 70kWh Tesla snakes a flattened cooling tube thru their cylindrical cells resulting in a very simple cooling scheme with very few points for leakage. Lund University / LTH / IEA / AR / MVKF25 /

23 BWM i3 125kW 21-33kWh The BMW i3 cools the bottom of the battery case with refrigerant eliminating the liquid coolant entirely. New energy dense lithium ion cells (50% more) Lund University / LTH / IEA / AR / MVKF25 / Integration example by BMW Lund University / LTH / IEA / AR / MVKF25 /

24 Integration example by Tesla 60kWh, 352V, 14 modules, 6216 cells in groups of 74=6x14 85kWh, 402V, 16 modules, 7104 cells Lund University / LTH / IEA / AR / MVKF25 / Integration example by Tesla Lund University / LTH / IEA / AR / MVKF25 /

25 Accommodation of cylindrical cells Lund University / LTH / IEA / AR / MVKF25 / Cool-plate and coolant Single stage heat transfer insufficient ha vs UA Lund University / LTH / IEA / AR / MVKF25 /

26 B. Sundén, Introduction to Heat transfer Heat transfer mapping 220 Cooling power, p= c p Q( out - in ) [W] Nusselts number, Nu=f(Re,Pr) [-] Heat transfer coefficient, h=nu k/d h [W/(m 2 K)] Temperature across boundary, P cool /(ha cool ) [ C] Pressure drop, dp 28[Pa] Ideal cooling supply power, 27 dpq [-] Cooling power, p= c flow rate, Q [L/min] p Q( out - in ) [W] flow rate, Q [L/min] flow rate, Q [L/min] flow rate, Q [L/min] flow rate, Q [L/min] flow rate, Q [L/min] flow rate, Q [L/min] flow rate, Q [L/min] outlet temperature, out [ C] outlet temperature, out [ C] outlet temperature, out [ C] outlet temperature, out [ C] outlet temperature, out [ C] outlet temperature, out [ C] outlet temperature, out [ C] wall temperature, out [ C] 100 Reynolds number, Re=2d h Q/(A ) [-] outlet temperature, out [ C] Driving parameters for cooling P=f( out,q) at in Flow (Re) and coolant (Pr) characterization Heat transfer correlations (Nu) and coefficient h Wall and winding temperature Pressure across cooling channel Power for supply Expected cooling power P=f( w,q) at in Lund University / LTH / IEA / AR / MVKF25 / cooling power, p= c p Q( out - in ) [W] 4000 c=3500j/kgk, =900kg/m flow rate, Q [L/min] Thermal analysis of cell assembly Hitachi 3.6v 35Ah 0.8mΩ@10A 155x27x118 incl terminals 810g Geometric data Defined by German standard DIN Heat transfer inside the cell From cell to module and pack Cell = Jelly-roll (heater) + carrier (assembly) Heating power Worst case P=I 2 R o =50W Lund University / LTH / IEA / AR / MVKF25 /

27 Thermal accessibility of a cell Available thermal connection areas Large long sides 2x134cm 2 but low thermal conductivity Sides, lateral sides 2x24cm 2 and Bottom side 39cm 2 Bottom and short sides have expectedly better inherit thermal contact Lund University / LTH / IEA / AR / MVKF25 / H. Lundgren et al, Thermal Management of Large-Format Prismatic Lithium-Ion Battery in PHEV Application Inside a battery cell DIN SPEC 91252:2011 Lundgren et al 2016 Cell dimensions are known, jelly-roll geometry only guessed Heat conductivity defined in-plane and cross-plane for whole cell unit and jelly roll (including heat capacity) Important part for thermal models are termination and equivalent jelly-roll Lund University / LTH / IEA / AR / MVKF25 /

28 H. Lundgren et al, Thermal Management of Large-Format Prismatic Lithium-Ion Battery in PHEV Application Surface temperature response Thermal vs electric power extraction and comparison Thermal conductivity Through-foil 0.95W/mK Along foil 30.8 W/mK Lund University / LTH / IEA / AR / MVKF25 / D FE over cross-sections 1 Q v =140W/dm 3, surf =30 o C 3 Temperature, [ C] λ cell =20 W/mK Case Q base [W] Q lateral [W] max [ o C] λ cell =1 W/mK Lund University / LTH / IEA / AR / MVKF25 /

29 Observations A Battery cell P=50 W heating, 1/R={ } K/W, Δ ={ } K Heat conductor Ideal 1/R=0 K/W, Δ =0 K Cooling plate Ideal fluid = wall = surf =30 o C cell = surf +Δ Source surf =30 o C wall =30 o C fluid =30 o C Link Sink 50 W per cell Lund University / LTH / IEA / AR / MVKF25 / Realization A Mechanical assembly in cross plane direction Thermal enhancement both in plane directions.. Lateral clamp or forcing plate Battery to base contact Lund University / LTH / IEA / AR / MVKF25 /

30 Cell clamped into heat conductor 1 Q v =140W/dm 3, surf =30 o C 3 Temperature, [ C] height, [m] length, [m] 10μm gap Δ gap =3 o C 100μm gap Δ gap =21 o C Case Q base [W] Q lateral [W] Lund University / LTH / IEA / AR / MVKF25 / max [ o C] Cell linked to cool-plate 1 2 Q v =140W/dm 3, fluid =25 o C 3 Temperature, [ C] Case Q base [W] Q lateral [W] max [ o C] height, [m] length, [m] h 1 =1000W/Km 2 wall Δ wall =15 o C h 2 =200W/Km 2 wall Δ wall =95 o C 2-h h Lund University / LTH / IEA / AR / MVKF25 /

31 Transient heating 5 minutes between the frames (FEMM transient HT) Hot side of the scale (usually presented in between o C) One dominating heat capacitance only Lund University / LTH / IEA / AR / MVKF25 / Summary Battery cell Δ b={ } 50W actual load is lower Heat conductor Insufficient thermal contact 0.1 mm air Δ 50W Cooling plate Insufficient heat transfer h 2 =200W/Km 2 wall Δ w l =95 o C cell = surf +Δ b surf = wall +Δ c wall = fluid +Δ w fluid =30 o C Source Link Sink 50 W per cell Lund University / LTH / IEA / AR / MVKF25 /

32 Thermal design, control and management.j. Li, Z. Zhu, Battery Thermal Management Systems of Electric Vehicles, MSc Chalmers /17.7 kwh &1700/270 kg Lund University / LTH / IEA / AR / MVKF25 /