WSP Canada Inc.

Lima eBus Battery Technology

Workshop Agenda

1. Introduction to Batteries & Electrical Systems

2. Battery Types & Chemistry

3. Evolution of Battery Technology1. Impact on Price ($/kWh)2. Impact on Energy Density (kWh/kg)

4. Lifecycle Considerations (Midlife)

5. End-of-Life Considerations (Secondary Markets for eBus Batteries)1. On-site Energy Storage2. Lithium Recycling

6. Charging Tradeoffs

7. Range vs. Passengers (Battery Trade off)

8. Session Wrap & Questions

Session 4Battery Technology9:00am to 10:00am

Battery & Chemistry Overview

How a Battery Works?

Battery Capacity (kWh) – How much energy a battery can hold on a charge

Battery Power (kW) – How much energy a battery can discharge/absorb as a rate of time

Chemical reaction of electrons moving from anode (-) to cathode (+) when load is applied

Flow reversed for recharging

How a Supercapacitor Works?

Electrostatic charge applied to plates

Positive (+) and Negative (-) charges build up on plates

Plate separation stores the energy (dielectric)

Once load is applied these charges flow in the direction of opposing plate

Supercapacitors in eBus DesignSofia, Bulgaria

• European market scan of over 40 battery electric buses from 20 OEMs

• WSP assisted in developing technical specification for 30 fast charging electric buses

• Project moving to procurement and pilot phase

• Chariot Motors Supercapacitor eBus vehicle design with on-route charging

Technology Comparison

Characteristic Battery Supercapacitor

Fast Charge/Discharge (kW)

Energy Storage Capacity (kWh)

Energy Storage Efficiency (kWh/kg)

SOC Retention (%)

Hazardous Chemicals & Materials

Evolution of Battery Technology

Battery Chemistry

• Evolution of chemistry in battery design

• Traditional Lead-Acid batteries used in diesel bus auxiliary system (i.e. alternator, starter motor)

• Move towards Li-Ion for eBus battery packs

BYD Lithium Iron Phosphate Battery

Conventional Diesel Bus Lead-Acid Battery

Battery ChemistryThere are several variants of Li-Ion battery chemistries:

• Lithium Cobalt Aluminium Oxide (NCA)

• Lithium Manganese Spinel (LMO)

• Lithium Iron Manganese Phosphate (LFMP)

• Lithium Iron Phosphate (LFP)

• Lithium Nickel Manganese Cobalt (NMC)

Projected consolidation as R&D focuses with most promising

technology

NMC vs. LFPLithium Iron Phosphate (LFP)• Notable eBus OEMs: BYD

Pros:• More tolerant to higher State-of-Charge (SOC) conditions and High Voltage• Lower battery cost (manufacturing)• Proven battery technology at high production/manufacturing volumeCons:• Lower energy density in comparison to NMC• Lower power storage ability

Lithium Nickel Manganese Cobalt (NMC)• Notable eBus OEMs: Proterra, New Flyer

Pros:• Higher energy density• Better thermal management, lower self-heating rateCons:• Still in active development (risk of technology outdating current batteries)• Higher battery cost (manufacturing)

Why Lithium-Ion• Highly reactive element and high energy density (kWh/kg)• Light weight in comparison to other battery metals (i.e. Lead (Pb) and Nickel (Ni))• Abundant resource

Market Bus Battery Sizes

North America

215 kWh (9m)266 kWh (10m)352 kWh (12m)446 kWh (18m)

76 kWh (12m)Xclesior 35ft (10m)• 100, 150, 200, 394 and

492 kWh

Xclesior 40ft (12m)• 100, 150, 200, 394,

492 and 590 kWh

Xclesior 60ft (18m)• 250, 689 and 885 kWh

Catalyst 35ft (10m)• 220 kWh (XR)• 440 kWh (E2)

Catalyst 40ft (12m)• 220 kWh (XR)• 440 kWh (E2)• 660 kWh (E2 max)

Market Bus Battery Sizes

South America

Andino K9G 12m324 kWh

Andino KF1 18m450 kWh

E12 324kWh

CityWide Electric 12m150 kWh

BYD D9W 324 kWh

Under development

Battery Pricing Trend

*Source Bloomberg New Energy Finance

Today’s Pricing:GM’s LG Chem battery cells $145/kWh

Tesla Li-Ion around $150/kWh today

Average lithium-ion $209/kWh

Tipping Point for EV adoption $100/kWh (est. 2025)Breakeven energy density with gasoline/diesel

Heavy duty fleets tend to cost $900/kWh

Energy Density Trend

• Energy density improving 6 to 8% per year

• Result of new battery chemistries, improved thermal management systems

Driving Factors for Energy Density1. Battery materials2. Cooling mechanisms of cells3. Manufacturing efficiency4. Improving chemical reaction of cells

(electrolyte solution conductance)

Current cell technology Li-ion 150 to 250 W per kg

Weight of 20 kWh Battery

Lead acid 550 kg

Nickel Cadmium 500 kg

Nickel Metal Hydride 350 kg

Lithium Ion 180 kg

Operational ConsiderationsBattery Size vs. Vehicle Weight

Increased battery size and vehicle weight impacts:• Passenger Capacity• Road Surface Conditions• Energy Efficiency (kWh/km)

• Need for energy density to continue improving to address passenger capacity and range anxiety

Lifecycle Considerations

Battery Degradation

Battery degradation occurs due to:

1. Calendar Ageing: degradation caused by the battery storage conditions and chemical breakdown among other factors (time dependent)

2. Cyclical Ageing: from battery charging and discharge (usage dependent)

• The depth of discharge (DoD) factor has an exponential relationship with battery degradation.

• If a battery is consistently only recharged to half its capacity then its degradation rate is approximately 4x slower than if the battery was consistently recharged 100% (DoD = 1).

OEM Recommendation: to complete battery charging as close to bus pull-out time as possible in order to minimize time the battery is at 100% SOC.

Plug-in Depot vs. On-route Charging

Plug-in Depot Charging On-route Pantograph Fast Charging

• Fast charging exposes battery cells to higher voltage (V) and amperage (A) to reduce charging time: • Battery cells exposed to higher temperature• Increased parasitic load for thermal management• Greater rate of cyclical fading

• Fast charging accelerates battery degradation• 1 to 1.5% per year (slow charge)• 3 to 5% per year (fast charge)

• NREL and other models under development to predict battery degradation

Midlife Considerations

1. Unproven lifecycle operations of eBuses

2. Budget for midlife battery pack replacement (est. $500/kWh)

3. Staff tooling, PPE and training requirements to service high voltage systems

4. Modular swap out of battery to capitalize on new battery technology

5. Include Battery State-of-Charge (SOC) warranty in vehicle specification

6. Reassign eBus to shorter routes to accommodate drop in battery capacity

End of Life Considerations

• Secondary market emerging for resale and recycle of Li-Ion batteries1. On-site energy storage microgrid applications2. Extraction and recycle of Lithium (currently not economically viable)

• As mass market adoption of electric vehicles occurs this will drive secondary market and recycling

• Need to consider end of life disposal/reuse for circular economy and sustainability

• Microgrid benefits (on-site storage)1. Peak shaving energy demand2. Support charging of eBus fleet

Fleet charging

Thank you!

Naeem FarooqiPrincipal Consultant

Toronto, Canada

416-644-0580Naeem.Farooqi@wsp.com

Twitter: naeemfarooqi11 Linkedin: Naeem Farooqi

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