The integration of second life EV battery and vehicle-to-grid charging into a Micro-

grid environment

by Xander Theron, uYilo e-Mobility programme

Introduction

•What is e-Mobility

•Storage technology within EV’s

•What happens at end of EV battery life

•Second life battery process and implementation factors

•Second life applications in a Micro-Grid environment

•Vehicle-to-grid technology

•Vehicle-to-grid application factors

Transitions to eMobility in our every day lives

Global Statistics

Source: IEA

The global electric car stock surpassed 2 million vehicles in 2016 after crossing the 1 million threshold in 2015

• 29% market share by Norway has incontestably achieved the most successful deployment

• China was by far the largest electric car market, accounting for more than 40% of electric cars sold worldwide

• India - Every car sold in India from 2030 will be electric

• France and Britain - No more petrol or diesel cars to be sold in the country by 2040

Global Projections

Diesel car sales are declining amid government clampdowns

• All Volvo cars to be electric or hybrid from 2019

• Jaguar Land Rover commits to all vehicles being electric or hybrid from 2020

Source: FT

Unpacking Electric vehicle battery packs

• Battery chemistry: Lithium-Ion cells

• Average life expectancy of 8-10 years, OEM’s use lower DOD to achieve high number of

cycles

• EV battery packs are fitted with Battery Management system (BMS) to ensure battery

operates safe and reliably

• Two important factors in battery status:

– State of charge (SoC): Level of charge stored in battery

– State of health (SoH): Remaining storage capacity of battery

• EV battery reach end of life when SoH<80%

What happens at end of life?

Source: Charged EV

•

•

•

Source: Nissan

Battery Second Life (B2L)

•

•

•

•

•

Source: BMW Source: BMW

2nd-life battery application factors and implementationsApplying the battery packs to a secondary application has the following advantages:

• Reduced cost of EV ownership, the owner can now sell the old battery at the end of EV battery

lifespan

• Business case for second life battery assessment and re-fitment

• Using less new batteries reducing impact of environment

• Battery storage could be cheaper enabling mass roll out benefiting various industries

Factors to consider for second life battery applications:

• Second life batteries will be competing with other battery chemistries that will be first life

• Second life battery performance and reliability still being assessed for feasibility which can impact the

value of the second life battery applications

• Cost of assessment and possible customized BMS fitment in the case of scaling the battery

Micro-Grids inclusive of Energy Storage Systems

The uYilo Micro-grid pilot project

• Solar energy generation (12kWh)

• Stationary second life EV battery for storage

• Demand side load management of charger network

• Individual charger load levelling

• Holistic energy management

• Reduced load onto local grid network

• Lower costs for grid infrastructure upgrades for EV charging

Micro-grid layout

Micro-grid layout

Typical South African daily demand cycle. Source: BusinessTech 2015

2nd-life battery application within a Micro-grid

Factors to consider:

• Battery pack high DC bus voltage interface to the inverter and DC bus

• BMS functionality to the energy management system via CAN bus

• Specified charging philosophy

• Battery pack balancing

• SOC/battery level indication

• Operating environment

Vehicle-to-Grid (V2G)

Source: Nissan

Vehicle-to-Home (V2H)

Source: Nissan

Vehicle-to-Grid (V2G) operating models

LTE Micro-Grid with Energy Management

LTE Micro-Grid with Energy Management

www.uYilo.org.za

Thank You * Re a leboga * Siyathokoza * Enkosi

Siyabonga * Re a leboha * Ro livhuha * Ha Khensa * Dankie