Electric Vehicles

Defining An Accuracy Limit in Battery State Estimation

Jiang, Shida
Tao, Shengyu
Lee, Jaewoong
Scott Moura
2026

Batteries are everywhere in our daily lives. Their applications span from electronic devices to electric vehicles (EVs) and further to grid-scale energy storage systems. Accurate battery state of charge (SOC) and state of health (SOH) estimations are essential elements of a battery management system (BMS) that ensure the safe and efficient operation of various battery-powered equipment. SOC describes the remaining charge of the battery. It is defined as the ratio of the instantaneous remaining capacity to its present maximum capacity....

Joint Fleet Sizing and Charging System Planning for Autonomous Electric Vehicles

Hongcai Zhang
Colin Sheppard
Tim Lipman
Scott Moura
2020

This paper studies the joint fleet sizing and charging system planning problem for a company operating a fleet of autonomous electric vehicles (AEVs) for passenger and goods transportation. Most of the relevant published papers focus on intracity scenarios and adopt heuristic approaches, e.g., agent based simulation, which do not guarantee optimality. In contrast, we propose a mixed integer linear programming model for intercity scenarios. This model incorporates comprehensive considerations of 1) limited AEV driving range; 2) optimal AEV routing and relocating operations; 3) time-varying...

Charging Infrastructure Demands of Shared-Use Autonomous Electric Vehicles in Urban Areas

Hongcai Zhang
Colin Sheppard
Tim Lipman
Teng Zeng
Scott Moura
2020

Ride-hailing is a clear initial market for autonomous electric vehicles (AEVs) because it features high vehicle utilization levels and strong incentive to cut down labor costs. An extensive and reliable network of recharging infrastructure is the prerequisite to launch a lucrative AEV ride-hailing fleet. Hence, it is necessary to estimate the charging infrastructure demands for an AEV fleet in advance. This study proposes a charging system planning framework for a shared-use AEV fleet providing ride-hailing services in urban area. We first adopt an agent-based simulation model, called BEAM...

Exploring Bidirectional Charging Strategies for an Electric Vehicle Population

Soomin Woo
Leo Strobel
Yuhao Yuan
Marco Pruckner
Tim Lipman
2025

Vehicle-grid integration (VGI) technologies control the energy exchange of electric vehicles (EVs) with power grids for economic and environmental benefits. Despite early investigations, it is still unclear how VGI operations should be designed to balance the goals of mobility needs and electrical grid operational costs. In this paper, our objectives are to examine VGI strategies including bidirectional or vehicle-to-grid (V2G) concepts reflecting realistic operation scenarios, evaluate the performance of the proposed strategies using actual EV charging data and future concepts for hourly...

Economic and Environmental Benefits for Electricity Grids from Spatiotemporal Optimization of Electric Vehicle Charging

Soomin Woo
Zhe Fu
Elpiniki Apostolaki-Iosifidou
Tim Lipman
2021
This article addresses the problem of estimating the potential economic and environmental gains for utility grids of shifting the electric-vehicle (EV) charging time and location. The current literature on shifting EV charging loads has been limited by real-world data availability and has typically therefore relied on simulated studies. Collaborating with a large automobile company and a major utility grid operator in California, this research used actual EV operational data and grid-operation data including locational marginal prices, marginal-grid-emission-rate data, and renewable-energy-...

Plug-in-Hybrid Vehicle Use, Energy Consumption, and Greenhouse Emissions: An Analysis of Household Vehicle Placements in Northern California

Brett Williams
Elliot Martin
Tim Lipman
Daniel Kammen
2011
We report on the real-world use over the course of one year of a nickel-metal-hydride plug-in hybrid—the Toyota Plug-In HV—by a set of 12 northern California households able to charge at home and work. From vehicle use data, energy and greenhouse-emissions implications are also explored. A total of 1557 trips—most using under 0.5 gallons of gasoline—ranged up to 2.4 hours and 133 miles and averaged 14 minutes and 7 miles. 399 charging events averaged 2.6 hours. The maximum lasted 4.6 hours. Most recharges added less than 1.4 kWh, with a mean charge of 0.92 kWh. The average power drawn was...

Analysis of The Combined Vehicle-and Post‐Vehicle-Use Value of Lithium‐Ion Plug-In-Vehicle Propulsion Batteries

Brett Williams
Tim Lipman
2011

Advances in electric-drive technology, including lithium-ion batteries, as well as the development of strong policy drivers such as California’s Global Warming Solutions Act, now contribute to a more promising market environment for the widespread introduction of plug-in vehicles in California. Nevertheless, battery costs remain high and uncertain, presenting significant hurdles to commercialization. This report builds upon previous research (CEC-500-2009-091) investigating the potential reduction in plug-in-hybrid battery lease payments that incorporation of value from postvehicle...

Strategy for Overcoming Cost Hurdles of Plug-In–Hybrid Battery in California: Integrating Post-Vehicle Secondary Use Values

Brett Williams
Tim Lipman
2010

Advances in electric drive technology, including lithium ion batteries as well as the development of strong policy drivers such as California's Global Warming Solutions Act, now contribute to a more promising market environment for the widespread introduction of plug-in vehicles in California. Nevertheless, battery costs remain high. This study explores a strategy for overcoming the significant hurdle to electric transportation fuel use presented by high battery costs. It describes offsetting plug-in-vehicle battery costs with value derived from post-vehicle stationary use of hybrid...

Aging Diagnostics for a Commercial Sodium-ion Cell: Experimental and Simulation-based Transfer from Lithium-ion Systems

Quade, Katharina Lilith
Sauer, Dirk Uwe
Scott Moura
2025

Sodium-ion batteries are gaining attention as a cost-effective and sustainable complementary technology to their lithium counterpart. However, fully realizing their drop-in potential and integrating them into applications requires a deeper understanding of their aging behavior, as well as the implications for the overall system. A high-power, cost-sensitive application is selected, where lithium-ion cells could potentially be replaced by a cheaper complementary technology with similar power characteristics and energy density. An extensive field dataset from this application is then...

Modeling the Future California Electricity Grid and Renewable Energy Integration with Electric Vehicles

Florian Triel
Tim Lipman
2020

This study focuses on determining the impacts and potential value of unmanaged and managed uni-directional and bi-directional charging of plug-in electric vehicles (PEVs) to integrate intermittent renewable resources in California in the year 2030. The research methodology incorporates the utilization of multiple simulation tools including V2G-SIM, SWITCH, and GridSim. SWITCH is used to predict a cost-effective generation portfolio to meet the renewable electricity goals of 60% in California by 2030. PEV charging demand is predicted by incorporating mobility behavior studies and...