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EV Batteries

Falling Prices

The uptake of today’s EVs has a lot to do with the advent of Lithium battery technology.  Lithium-ion batteries are comparatively lightweight, energy dense and capable of being re-charged many times.  They are at least three times lighter than equivalent lead acid batteries, approximately three times more powerful and offer three times the cycle life.  In the July 2012 quarterly, McKinsey & Company reported that the price of lithium-ion batteries could fall dramatically by 2020 potentially disrupting the transportation, power, and petroleum sectors.  Current lithium-ion costs are about $500 per kilowatt hour – the McKinsey article sees this price dropping to about $200 kWh by 2020 and $160 by 2025.  Others such as Navigant Research are predicting the price to drop to $300 by 2015.  EV battery prices have already dropped 40% between 2010 and 2012. No matter who gets the figures right it is an inevitability that prices will fall pretty dramatically over the next 5 years removing the biggest cost impediment to more widespread EV adoption.

Environmental Concerns

According to Kate Krebs from the U.S. National Recycling Coalition, “Lithium Ion batteries are classified by the federal (U.S.) government as non-hazardous waste and are safe for disposal in the normal municipal waste stream.”

The metals in lithium ion batteries – cobalt, copper, nickel and iron – are considered safe for landfills or incinerators. The lithium in lithium ion batteries is in an ionic form (hence the name) but they do not contain lithium metal which is very reactive and corrodes quickly in air. It is also highly flamable in its elemental state.

How Lithium Ion batteries are made:

Lithium ion batteries are made from nontoxic lithium carbonate (often used in ovenware), nontoxic cobalt oxide (used as a pottery glaze), nontoxic graphite (used in pencils), and a polymer (plastic) membrane. The most toxic components in the final product are the electrolyte and lithium cobalt oxide, neither of which are persistent in the environment and both of which are increasingly being replaced by more benign compounds.

However why would anyone want to dispose of this profitable resource in landfill when it can be recycled. At Tesla for example its EV batteries are recycled with Umico in Europe and with Kinsbursky Brothers in North America for a tidy profit.

Here’s an extract from an article on Tesla’s Closed Loop Battery Recycling Program.
“At Tesla we have been refining our recycling program for years. Before sending our battery packs to be recycled we can reuse about 10% of the battery pack (by weight), e.g. the battery case and some electronic components. In North America we work with Kinsbursky Brothers to recycle about 60 percent of the battery pack. In Europe, we recently started working with Umicore, and now that we are selling cars in Japan and the Asia Pacific region, we will soon have news about recycling in Asia.

Let’s focus on Tesla’s recycling process with Umicore, which is the first time we’ve been able to use a closed loop recycling system. Umicore’s factory plants are able to recycle our batteries into completely reusable materials and substantially reduce the carbon footprint of manufacturing Lithium-ion batteries.

The Umicore battery recycling technology is able to save at least 70 percent on CO2 emissions at the recovery and refining of these valuable metals. It does this by creating “products” and “byproducts,” rather than following a mechanical separation process.”
Click here for the full article.

Recycling lead acid batteries from vehicles is one of the world’s most successful recycling stories with a recycling rate over 90%.  As can be seen from Tesla’s experience, recycling Lithium batteries not only makes environmental sense it makes economic sense. 

Battery Research

Research into lithium batteries has accelerated over the past the past ten years with the promise of energy density being quadrupled or even enhanced by a factor of ten.  Promising areas of research are for lithium-vanadium-phosphate batteries (also called vanadium redox flow batteries), lithium-sulphur batteries and lithium-air batteries.

Lithium Vanadium Phosphate

The vanadium flow batteries (VFBs) hold enormous promise in battery storage technology and have been touted as the next big thing.

When applied to EVs the higher voltage in this type of battery results in higher speed and acceleration.  The energy density of this battery will result in more light weight EVs.

LVP batteries charge faster and also have a higher life expectancy than current lithium-ion batteries.

Lithium-sulphur batteries would increase the energy density of batteries by a factor of four whereas lithium-air would increase the energy density up to a factor of ten.

There are challenges to develop and commercialise both types of batteries.

Lithium Sulphur

Lithium-sulphur batteries have a shorter lifespan than current lithium-ion batteries and can’t be charged as many times.  Pacific Northwest National Laboratory (PNNL) announced on 9th Jan 2014 they have developed a hybrid anode for lithium-sulphur batteries that increases the cycle rate of this type of battery by providing a graphite shield around the anode.

Research carried out at Stanford University is providing battery researchers with tools that investigate the way the battery behaves in real time.

Lithium Air

IBM started investigating lithium-air battery technology in 2009 with the Battery 500 Project.  There are certainly challenges to develop air breathing batteries but the prize is a battery with the energy density of gasoline.  This would extend the range of EVs approximately tenfold.

click here for more information on the IBM 500 project.

Solid State Batteries

Solid state lithium batteries present the most potential for breakthrough over the next few years.  Density levels in lithium ion batteries (those with a liquid electrolyte) have been improving markedly over the past 20 years (about tripled) but the improvement curve is finite for this type of technology and only so much tweaking can be done.  Solid state batteries (no liquid electrolyte) offer much higher energy density than current lithium ion batteries (about double) – have much less fade, they are easier to shape, have no fire risk and don’t swell!  Solid state batteries remove much of the complexity built in to today’s lithium ion batteries.
The manufacturing process for solid state batteries is very similar to a number of current industrial processes so there’s no major work to be done on tooling up for manufacture.  Because of this, the potential for solid state EV batteries to be introduced over the next two to three years is reasonably high.  One particular company developing this technology right now is Sakti3, headed up by Dr. Ann Marie Sastry.  There are a number of youtube videos featuring Anne Marie describing solid state batteries.

Aluminium-Ion Battery

Researchers at Stanford University have announced their discovery of an aluminium-ion battery in the journal Nature that holds promise of cheap, ultra-fast charging, flexible batteries with thousands of charge cycles.  The team led by Professor Hongjie Dai made the accidental discovery of using a graphite cathode that proved to have quite astounding results.  Aluminium batteries have long held promise as an advanced technology as they are cheap, safe (non flammable) and capable of high-charge storage capacity.  Part of the problem however is that charge cycles have been miserably poor.

By using the graphite cathode in the make up the researchers discovered the cycle rate (number of charge discharge cycles) was in the thousands with virtually no loss of capacity.  Lithium-ion batteries suitable for EVs usually have a cycle life of about 1,500 – the researchers claim a cycle rate for the experimental batteries of 7,500.

There is still work to be done on these batteries but this could be a major breakthrough. These batteries could potentially charge a mobile phone in a minute rather than the hours it currently takes using lithium-ion technology.  Read more here.

1,600 Kilometer Range? It’s already here

The aluminium manufacturer Alcoa has teamed up with Israeli based company Phinergy and announced the development of a battery that will deliver a 1,600 kms range for EVs.  The aluminium air battery’s only servicing requirement is for water top ups every three or four hundred kilometers.  Energy is released through the reaction of aluminium and water when mixed with oxygen (from the air) using a silver based catalyst.  The venture has already tested the battery and intends to go into production late 2014.  This type of battery is one use – it cannot be recharged and because of this is being promoted as a supplemental technology.
The battery could be used in hybrids or pure electrics as a supplement to the existing lithium-ion battery pack.  It would certainly put paid to the limited range currently viewed by many as a drawback to EV adoption.  When the battery is depleted it is simply replaced giving a further 1,600 kms of range.  There is no mention on the Phinergy website of the amount of electricity used to create the aluminium which is an electricity intensive industrial process.  This is however a demonstration that battery technology can deliver extended range for electric vehicles.

Peak Lithium

Lithium is considered a comparatively rare element (actually a rare earth metal) according to the Handbook of Lithium and Natural Calcium with limited world supplies, (discounting the seemingly inexhaustible amount of 230 billion tonnes found in sea water).  The current EV recycling programs will be expanded further as battery use accelerates.

Having said that research carried out in 2004 sponsored by the United States Department of Energy, Office of Transportation Technologies, Office of Advanced Automotive Technologies indicates that supply of the materials used in the construction of lithium batteries (including the lithium) will not be problematic.  Further research carried out by the University of Michigan in conjunction with Ford motor company in 2010 indicates there are sufficient resources for the remainder of this century.  Technology to extract lithium from seawater has been developed by South Korean company POSCO.  There is simply no basis to think there will be a shortage of lithium in the way we have come to understand peak oil.