lithium – Battery Education

Lithium Cell Manufacturing Part 2

In this current series on lithium cell manufacturing we are going to be looking at the processes that are used to construct a lithium battery cell. These processes are highly technical and require complete precision in order to make an individual battery cell function according to the specific power demands of the device that the cell will ultimately be used within.

On a macro level when we look at a battery we see completed unit (which we call a battery) however the battery is actually an assembled collection of material and hardware. The outside plastic cover is called the casing. The casing encloses and hermetically seals the battery cell and specialized hardware. Battery casing is manufactured in layers. The casing layers are developed from various raw materials and can include one or two, for example, of polyethylene terephthalate layers, a polymer layer, and a polypropylene layer. Another example may be a casing with layers of carbonized plastic.

Within the casing is the hardware and the battery cell. When we look inside a lithium based battery cell, for example, there are four main components and they include:

The lithium (which acts as an anode)
The metallic oxide cathode
The electrolyte
The metallic current collector

Lithium

As noted above lithium within the battery cell is used as the battery’s anode. The anode is the part of the cell that acts an electrical conductor (electrode) through which electrical current flows into a polarized device. As current flows into the lithium, a chemical process called intercalation occurs. Intercalation is the joining of a molecule (or molecule group) between two other molecules (or groups). When it comes to charging your battery you are in effect pushing ions in and out of solid lithium compounds. These compounds have minuscule spaces between the crystallized planes for small ions, such as lithium, to insert themselves from a force of current. In effect ionizing the lithium loads the crystal planes to the point where they are forced into a current flow. The current flow is then channeled back and forth from anode to cathode and thereby creating an electrical flow to power on your device.

To create an electrical flow from lithium you have to move the lithium. To move the lithium chemistry (lithium-ion, lithium polymer, lithium iron phosphate, etc) you have to have a minimum voltage applied to the lithium. Most battery cells are charged up to 4.2 volts with relative safe workings at about 3.8 volts. Anything less than 3.3 volts will not be enough to charge or move the chemistry. One thing to note here is that volts are an algorithmic measurement of current. So in a sense to create current through your battery you have to introduce current into your battery’s lithium.

The Metallic Oxide Cathode

The cathode is an electrode (electrical conductor) by which electrical current flows out of a polarized electrical device. The metallic oxide component of the cathode is the composition of the cathode. Metal oxides are crystalline solids that contain a metal cation (an ion with more protons than electrons)and an oxide anion (an ion with more electrons than protons).

The Electrolyte

In the battery cell the electrolyte solution is the conducting medium in which the flow of electric current passes through between the electrodes. Electrolytes can be wet, solid, gel, or dry. Dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry. Dry polymers do not conduct electricity but allows for ion exchange. The real benefit is the fact that the dry polymer design is only one millimeter (0.039 inches) thick. The drawback is that the dry polymer design suffers from poor conductivity. Today lithium hexafluorophosphate and tetrafluoroborate are the preferred electrolyte salts for lithium batteries.

The Metallic Current Collector

A current collector is an inert structure of high electrical conductivity used to conduct/transmit current from or to an electrode during discharge or charge. There a variety of metal based current collector from zinc to liquid metal that can provide a good conductive path between the electrodes.

Closing

From the above we can see that a battery cell, being just one component of a battery is a highly complex system. As we move into the next portion of the series we will break down each of these 4 key components of a battery cell and see how they are actually made.

Until next time, Dan Hagopian – www.batteryship.com
Copyright © BatteryEducation.com. All rights reserved.

How Much Demand for Lithium is There?

Lithium is used in a very wide variety of resources including lithium for use in primary and secondary batteries. This type of lithium is called battery grade metal. Battery grade lithium has been on the increase by about 25% year over year since 2000. With the push for lithium to be used in electric cars the obvious question would be is how much lithium is available worldwide?

In the most recent edition of “The Economics of Lithium” (Roskill Market Reports, 11th Edition, 2009), worldwide lithium reserves are as follows:

Current worldwide production is about 22,800 tonnes Lithium. (or 114,000 tonnes carbonate)*
Current worldwide demand is about 23,000 tonnes Lithium. (or 122,000 tonnes carbonate)*
Current estimates of worldwide Lithium reserves total about 30,000,000 tonnes Lithium (or 150,000,000 tonnes Lithium Carbonate)*

Interesting the world’s supply of lithium is concentrated by producers in very few countries. The largest concentration of lithium is in the America’s (Argentina and Chile). Australia also has a large producer, Talison Minerals, and in the U.S. Chemetall is the only U.S. domestic source of lithium raw material and the largest global producer of lithium and lithium compounds used in batteries, pharmaceuticals and many other industries.

According to the USGS (U.S. Geological Survey, Mineral Commodity Summaries, January 2010):

identified lithium resources the United States total 2.5 million tons
identified lithium resources for Bolivia total 9 million tons
identified lithium resources for Chile total in excess of 7.5 million tons
identified lithium resources for Argentina total in excess of 2.5 million tons
identified lithium resources for China total in excess of 2.5 million tons

Until next time, Dan Hagopian – www.batteryship.com
Copyright © BatteryEducation.com. All rights reserved.

What Raw Minerals Are Used To Make a Battery?

To build a battery you have four basic overarching battery components including the casing, chemistry, electrolyte, and the internal specialized hardware. At the core of these four basic overarching battery components are the foundation blocks; the raw materials necessary for the construction of a battery. Minerals and materials used in the construction of batteries are numerous but the core mineral required to have a battery is the batteries chemical which can either be : cadmium, cobalt, lead, lithium, and nickel (along with other rare earth elements). Why is the chemical one of the most important element in a battery: because a battery at its most basic element is a system that converts and stores electrochemical energy for the purpose of providing portable power to a device. Without the chemistry changing chemical energy into electrical energy is impossible. So needless to say the availability of minerals used in batteries are highly important!

Incidentally the available raw material supply and price often times dictates how much your battery is going to be – if the raw material price is higher, than, your battery cost will be higher (the converse of that is also true). But what are the current supplies of the battery making minerals and how much demand is out there for these minerals?

In the United States there are currently 6,841 different mining operations ranging from aluminum to zircon. Although 6,841 mines sounds like a lot of mining operations you must evaluate that number against the total demand of minerals. Consider that every American born in 2007 is estimated to use the following amounts of nonfuel mineral commodities over their lifetime (data pulled from MII):

Aluminum (bauxite) 5,677 pounds
Cement 65,480 pounds
Clays 19,245 pounds
Copper 1,309 pounds
Gold 1,576 ounces
Iron ore 29,608 pounds
Lead 928 pounds
Phosphate rock 19,815 pounds
Stone, sand, and gravel 1.61 million pounds
Zinc 671 pounds

Now consider that there were 4,315,000 babies born in 2007 (U.S. Census Bureau). So when you start multiplying the amounts of estimated use of each of the minerals you can quickly see 6,841 mines is not really a whole lot!

Lithium, Cadmium, Cobalt, Nickel By The Numbers

Chile was the leading lithium chemical producer in the world with Argentina, China, and the United States as additional major producers. The United States remained the leading consumer of lithium minerals and compounds and the leading producer of value-added lithium materials. Incidentally only one company produced lithium compounds in the U.S. and that is at the Silver Peak Mine in Nevada run by the Chemetall Foote Corporation. Lithium is used not only in batteries but also in ceramics and glass, lubricating greases, pharmaceuticals and polymers, air conditioning, primary aluminum production, continuous casting, chemical processing and other uses. In terms of annual quantity of lithium the USGS estimates that in the U.S in 2005 5,000,000 pounds of lithium was used in rechargeable batteries.

In terms of annual quantity of cadmium the USGS estimates that in the U.S in 2005 1,312,000 pounds of cadmium was used in rechargeable batteries.

In terms of annual quantity of cobalt (cobalt is used primarily for the battery’s electrodes) the USGS estimates that in the U.S in 2005 23,800,000 pounds of cobalt was used in rechargeable batteries.

In terms of annual quantity of nickel the USGS estimates that in the U.S in 2005 426,000,000 pounds of nickel was used in rechargeable batteries.

How Much Demand is there for these Minerals?

In 2002 it is estimated that 350 million batteries were purchased in the U.S. So if you assume that the past 7 years have been fairly consistent then you could assume that 2.4 Billion batteries were bought and in use and will eventually need to be recycled and replaced. This means that an ever increasing demand for minerals will be placed on the mines of the earth.

Thankfully there is enough available minerals and metals to be extracted from mines that at least for the time being we do not have to be overly concerned, but, indeed there will come a point decades down the road, that this will not always be true.

Rechargeable Batteries Can Only Be Charged 300-500 Times – Part 2

In the last two articles we addressed how and why rechargeable batteries have limited charge cycles. We reviewed in detail the effect of a charge-discharge cycle – a chemical change in a battery system that results in degradation and power loss. But there is one aspect in my last article that deserves special attention. This one factor is the basis of battery degradation. It is the reason why batteries can never just keep going and going and going. The fact is, is that all batteries degrade and lose power because there is a reduction in the battery’s active material.

We know that a battery is a device that converts chemical energy into electrical energy. In order to convert chemical energy into electrical energy there is a chain of events that have to occur prior to the creation of electrical energy. The chain of events have been discussed in depth in previous articles which you can access on my blog but what is key to the creation of electricity is that in batteries electrical energy is produced from two chemicals in a solution. After discharging you recharge the battery via a charger. The charge process involves intercalation: the joining of a molecule (or molecule group) between two other molecules (or groups). Intercalation is the process of ions being pushed by electrical current into solid lithium compounds. Lithium is one of the chemical components used to create electrical energy in batteries. Lithium compounds have minuscule spaces between the crystallized planes for small ions to insert themselves from a force of current. Ionizing lithium loads the crystal planes to the point where they are forced into a current flow. Intercalation replenishes, in effect, lithium but the net result of ionization is the ultimate depletion of the lithium reactive property. You could say if you use it you will lose it!

Why then is lithium used as the chemical to create electricity in batteries? There are a number of good reasons – let’s look at a few!

General Characteristics of Lithium

Name: lithium
Symbol: Li
Atomic number: 3
Atomic weight: [6.941 (2)] g m r
CAS Registry ID: 7439-93-2
Group number: 1
Group name: Alkali metal
Period number: 2
Block: s-block
Standard state: solid at 298 K
Color: silvery white/grey
Classification: Metallic

Lithium is one of the metals in the alkali group (the other metals include Sodium, Potassium, Rubidium, Cesium, and Francium). Lithium is a highly reactive metal. Lithium has only one electron in its outer shell (two electrons in its inner shell), which makes it chemically “ready” to lose that one electron in ionic bonding with other elements. Lithium is used as a battery anode material (due to its high electrochemical potential). Electrochemical potential is the sum of the chemical potential and the electrical potential. The higher the electrochemical potential the better the electrical current yields. In some lithium-based cells the electrochemical potential can be five times greater than an equivalent-sized lead-acid cell and three times greater than alkaline batteries. One other core advantage that lithium has is that it is soft and bendable which allows for tight configurations in small cell designs (PDAs. Laptops, Cameras etc…).

Lithium, even with all of its good chemical properties will eventually, however, react to the point where the electrochemical potential will yield a charge that is simply not enough to create current to pass to power a device.