Battery Power - 2012 Resource Guide - (Page 9)

Feature Article Cost and Performance of Electric Vehicle Batteries Celine Cluzel, Shane Slater, Element Energy George Paterson, Rebecca Trengove, Axeon Recognizing the threat of rising temperature brought by climate change and what, as a developed country, the UK’s fair contribution to the global effort should be, the UK Government has set a legally binding target of 80 percent CO2 reduction by 2050 compared to 1990. The Committee on Climate Change (CCC) is an independent body that advises the UK Government on setting and meeting carbon reduction targets and on preparing for the impacts of climate change. Given that around 22 percent of UK CO2 emissions are from surface transport, deep cuts in emissions from this sector are required. Decarbonization of road transport will rely on the electrification of vehicles combined with increased renewable electricity generation. Although electric vehicles (EVs) have been available to consumers for a number of years, uptake to date has been low, largely due to the higher capital cost of EVs relative to traditional vehicles. The battery is a key component in EVs, with a significant impact on overall cost and vehicle performance. The CCC therefore commissioned Element Energy (a UK energy consultancy), Axeon (Europe’s leading independent designer and manufacturer of lithium-ion EV battery systems) and Professor Peter Bruce of St Andrews University, Scotland (an expert on lithium batteries) to investigate the future trajectory of EV batteries’ cost and performance. The team developed a detailed cost model capable of analyzing costs of current and future cell chemistries, made robust by collecting the latest empirical data and interviewing industry experts, including cell suppliers, cell component manufacturers and battery pack manufacturers. 1. Current Performance Characteristics A range of battery chemistries has been deployed in EVs, most notably nickel metal hydride used in the Toyota Prius. However, lithium family chemistries have become the dominant chemistry for pure EV and Plug in Hybrid EV (PHEV) applications, implying that energy density is the most important metric in battery design. Currently, cells suitable for transport applications typically have an energy density of 100 to 180 Wh/kg and are available at a capacity of 40 Ah/cell. Based on laboratory testing the expected life of cells is 1,000+ cycles and five to 10 years, depending on cell chemistries and how the battery is managed. It should be noted that due to the development time-lag in the automotive market between the mule (proof of concept vehicle) and the final production vehicle, which can take three to four years, pack life is yet to be tested in real world conditions. Because high temperatures diminish the life of the cells, thermal control is critical, and the associated costs must be included in pricing models. www.BatteryPowerOnline.com Achieving a 10 year battery life in automotive applications requires careful thermal and operational management, a task fulfilled by the Battery Management System (BMS). The BMS is an essential component within a multiple cell battery pack, monitoring the state of a battery, measuring and controlling key operational parameters, and thus ensuring safety and life. The BMS, housing and other components add weight and reduce the energy density of the battery, typically to 100 Wh/kg. For comparison, gasoline has an energy density of 13,000 Wh/kg. 2. Current Price Characteristics Cell prices have been relatively stable in recent years, with prices partly reflecting the strategy of different cell suppliers (e.g. to secure market share) as well as quality differences. Today’s average EV cell price can be approximated at $400 to $450/kWh. However, high power cells, i.e. for hybrid applications, are typically 30 percent more expensive, though it is harder to generalize on price here as it is very sensitive to the power performance and total pack size. The cells however represent only 60 percent of the total pack price; non-cell components bring the price to approximately $730/kWh for a midsize car. These components include the BMS, power electronics, wiring harnesses, pack housing and thermal management. Therefore for a midsized car with ~100 mile range, a typical battery system might cost around $22,000 (weight ~300 kg, 30 kWh, 80 percent usable energy). Cell materials (electrodes, separator and electrolyte) account for around 30 percent of the overall pack price, with the electrodes being the most expensive components. Their cost is expected to decrease by reducing the amount of high-priced materials such as nickel and cobalt or developing cell materials that deliver more vehicle range per mass, i.e. with higher energy density. Non-cell pack components account for another 30 percent of the overall pack price, with the BMS, housing and power electronics particularly significant. Standardization of these components, currently customized for each vehicle model in the Overview of Current Lithium-Ion Batteries 2012 Resource Guide • Battery Power 9  http://www.BatteryPowerOnline.com

Table of Contents for the Digital Edition of Battery Power - 2012 Resource Guide

Global Market for Battery Control Technology: Battery Chargers, Smart Batteries and Battery Conditioners
Cost and Performance of Electric Vehicle Batteries
Battery Power 2012 Conference Preview
Battery Manufacturers
Battery Chemistries
Markets/Industry Served
Suppliers
Marketplace
Calendar of Events

Battery Power - 2012 Resource Guide

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