Battery specifications
Lithium-ion battery of Varta, Museum Autovision, Altlußheim, Deutschland
Energy/weight	160 Wh/kg
Energy/size	270 Wh/l
Power/weight	1800 W/kg
Charge/discharge efficiency	99. Museum Autovision is a museum for Cars, Motorcycles, Bicycles most of NSU Motorenwerke AG and Alternative propulsion in Altlußheim is a municipality in Baden-Württemberg and belongs to Rhein-Neckar-Kreis. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. The litre or liter (see spelling differences) is a unit of Volume. The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. 9%[1]
Energy/consumer-price	2. 8-5 Wh/US$[2]
Self-discharge rate	5%-10%/month
Time durability	(24-36) months
Cycle durability	~1200 cycles
Nominal Cell Voltage	3. The United States dollar ( sign: $; code: USD) is the unit of Currency of the United States; it has also been 6 / 3. 7 V

Lithium-ion batteries (sometimes abbreviated Li-ion batteries) are a type of rechargeable battery in which a lithium ion moves between the anode and cathode. The volt (symbol V) is the SI derived unit of electric Potential difference or Electromotive force. See also Rechargeable electricity storage system A rechargeable battery, also known as a storage battery, is a group of two or more secondary Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 An anode is an Electrode through which Electric current flows into a polarized electrical device A cathode is an Electrode through which (positive Electric current flows out of a polarized electrical device The lithium ion moves from the anode to the cathode during discharge and from the cathode to the anode when charging.

Lithium ion batteries are commonly used in consumer electronics. Consumer electronics include electronic equipment intended for everyday use They are currently one of the most popular types of battery for portable electronics, with one of the best energy-to-weight ratios, no memory effect, and a slow loss of charge when not in use. Energy density is the amount of Energy stored in a given system or region of space per unit Volume, or per unit Mass, depending on the context although Memory effect, also known as lazy battery effect or battery memory, is an effect observed in nickel cadmium Rechargeable batteries that causes them to Self-discharge is a phenomenon in batteries in which internal chemical reactions reduce the stored charge of the battery without any connection between the electrodes In addition to uses for consumer electronics, lithium-ion batteries are growing in popularity for defense, automotive, and aerospace applications due to their high energy density. However certain kinds of mistreatment may cause Li-ion batteries to explode.

The three primary functional components of a lithium ion battery are the anode, cathode, and electrolyte, for which a variety of materials may be used. An anode is an Electrode through which Electric current flows into a polarized electrical device A cathode is an Electrode through which (positive Electric current flows out of a polarized electrical device An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium Commercially, the most popular material for the anode is graphite, although materials such as TiS₂ (Titanium disulfide) were originally used. The Mineral graphite, as with Diamond and Fullerene, is one of the Allotropes of carbon. ^[3] The cathode is generally one of three materials: a layered oxide, such as cobalt oxide, a polyanion, such as lithium iron phosphate, or a spinel, such as manganese oxide. Lithium iron phosphate (LiFePO4 is a compound used in lithium iron phosphate batteries (related to Li-Ion batteries) The spinels are any of a class of Minerals of general formulation XY2 O 4 which Crystallize in the cubic (isometric Depending on the choice of material for the anode, cathode, and electrolyte the voltage, capacity, life, and safety of a lithium ion battery can change dramatically. Lithium ion batteries are not to be confused with lithium batteries, the key difference being that lithium batteries are primary batteries containing metallic lithium while lithium-ion batteries are secondary batteries containing an intercalation anode material. Lithium batteries are not to be confused with lithium-ion batteries which are high energy-density rechargeable batteries Lithium batteries are A primary cell is any kind of Electrochemical cell in which the electrochemical reaction of interest is not reversible so used in Disposable See also Rechargeable electricity storage system A rechargeable battery, also known as a storage battery, is a group of two or more secondary

History

Lithium ion batteries were first proposed by M.S. Whittingham, then at Exxon, in the 1970s. M Stanley Whittingham (born Manly Stanley Whittingham, 1941 is an American Chemist. Exxon is a brand of fuel sold by ExxonMobil. History Exxon formally replaced the Esso, Enco, ^[4] Whittingham used titanium sulfide as the cathode and lithium metal as the anode. Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3

Lithium batteries in which the anode is made from metallic lithium pose severe safety issues. As a result, lithium-ion batteries were developed in which the anode, like the cathode, is made of a material containing lithium ions. Lithium-ion batteries came into reality when Bell Labs developed a workable graphite anode^[5] to provide an alternative to lithium metal, the lithium battery. Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) is the Research organization Lithium batteries are not to be confused with lithium-ion batteries which are high energy-density rechargeable batteries Lithium batteries are Following groundbreaking cathode research by a team led by John Goodenough^[6], the first commercial lithium-ion battery was released by Sony in 1991. John Bannister Goodenough is an American Professor and prominent Solid-state physicist. is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with The cells utilised layered oxide chemistry, specifically lithium cobalt oxide. Lithium cobalt oxide (LiCoO2 is a Chemical compound commonly used in the positive Electrodes of Lithium-ion batteries. These batteries revolutionised consumer electronics.

In 1983, Michael Thackeray and coworkers identified manganese spinel as a cathode material. The spinels are any of a class of Minerals of general formulation XY2 O 4 which Crystallize in the cubic (isometric ^[7] Spinel showed great promise, since it is a low-cost material, has good electronic and lithium ion conductivity, and possesses a three-dimensional structure which gives it good structural stability. Although pure manganese spinel fades with cycling, this can be overcome with additional chemical modification of the material. ^[8] Manganese spinel is currently used in commercial cells. ^[9]

In 1989, Arumugam Manthiram and John Goodenough of the University of Texas at Austin showed that cathodes containing polyanions, eg. John Bannister Goodenough is an American Professor and prominent Solid-state physicist. sulfates, produce higher voltage than oxides due to the inductive effect of the polyanion. ^[10] Following this, in 1996 Goodenough and co-workers discovered the electrochemical utility of the olivine material lithium iron phosphate, LiFePO₄. John Bannister Goodenough is an American Professor and prominent Solid-state physicist. Lithium iron phosphate (LiFePO4 is a compound used in lithium iron phosphate batteries (related to Li-Ion batteries) It is an important and emerging cathode material for lithium-ion batteries due in part to its enhanced safety compared to other lithium-ion chemistries. Cells containing lithium iron phosphate cathodes have been commercialised by multiple companies, including Phostech, Valence Technology, A123Systems, Aleees and Lithium Technology Corp. Valence Technology Inc sells various types of Phosphate -based Lithium-ion rechargeable batteries, including N-Charge and U-Charge and has recently A123Systems is a supplier of high-power Lithium-Ion batteries

These batteries are generally used in mobile phones,digital clocks etc.

Electrochemistry

The three participants in the electrochemical reactions in a lithium ion battery are the anode, cathode, and electrolyte. An anode is an Electrode through which Electric current flows into a polarized electrical device A cathode is an Electrode through which (positive Electric current flows out of a polarized electrical device An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium

Both the anode and cathode are materials into which and from which lithium can migrate. The process of lithium moving into the anode or cathode is referred to as insertion (or intercalation), and the reverse process, in which lithium moves out of the anode or cathode is referred to as extraction (or deintercalation). When a cell is discharging, the lithium is extracted from the anode and inserted into the cathode. In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy When the cell is charging, the reverse process occurs: lithium is extracted from the cathode and inserted into the anode. In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy

The anode of a conventional Li-ion cell is made from carbon, the cathode is a metal oxide, and the electrolyte is a lithium salt in an organic solvent. An anode is an Electrode through which Electric current flows into a polarized electrical device Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 A cathode is an Electrode through which (positive Electric current flows out of a polarized electrical device An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. ^[11]

Useful work can only be extracted if electrons flow through an external circuit. Therefore the half reactions are enlightening. The following equations are written in units of moles, making it possible to use the coefficient x. The cathode half reaction (with charging being forwards) is: ^[12]

The anode half reaction is:

This reactions has limits. Overdischarge will supersaturate lithium cobalt oxide, leading to the production of lithium oxide, ^[13] possibly by the following irreversible reaction:

It is important to note that lithium ions themselves are not being oxidized; rather, in a lithium-ion battery the lithium ions are transported to and from the cathode or anode, with the transition metal, Co, in Li_xCoO₂ being oxidized from Co³⁺ to Co⁴⁺ during charging, and reduced from Co⁴⁺ to Co³⁺ during discharge. Lithium oxide ( Li2[[Oxygen O]] or lithia is an Inorganic Chemical compound. Cobalt (ˈkoʊbɒlt is a hard lustrous silver-grey Metal, a Chemical element with symbol Co.

Cathodes

Electrolytes

Liquid electrolytes in Li-ion batteries consist of solid lithium-salt electrolytes, such as LiPF₆, LiBF₄, or LiClO₄, and organic solvents, such as ether. Liquid is one of the principal States of matter. A liquid is a Fluid that has the particles loose and can freely form a distinct surface at the boundaries of An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium Lithium hexafluorophosphate ( Li[[phosphorus P]] F 6 is an inorganic chemical compound Lithium tetrafluoroborate is a chemical compound with the formula LiBF4 Lithium perchlorate is the Chemical compound with the formula LiClO4 An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. Diethyl ether, also known as ether and ethoxyethane, is a clear colorless and highly Flammable liquid with a low Boiling point and a A liquid electrolyte conducts Li ions, which acts as a carrier between the cathode and the anode when a battery passes an electric current through an external circuit. An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium A cathode is an Electrode through which (positive Electric current flows out of a polarized electrical device An anode is an Electrode through which Electric current flows into a polarized electrical device However, organic solvents are easily decomposed on anodes during charging, thus preventing battery activation. An anode is an Electrode through which Electric current flows into a polarized electrical device Nevertheless, when appropriate organic solvents are used for electrolytes, the electrolytes are decomposed and form a solid electrolyte interphase (SEI)^[14] at first charge that is electrically insulating and high Li-ion conducting. A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. The interphase prevents decomposition of the electrolyte after the second charge. For example, ethylene carbonate is decomposed at a relatively high voltage, 0. Ethylene carbonate, is an Ester of Ethylene glycol and Carbonic acid. 7 V vs. Li, and forms a dense and stable interface.

See uranium trioxide for some details of how the cathode works. Uranium trioxide (UO3, also called Uranyl oxide, uranium(VI oxide, and uranic oxide, is the hexavalent Oxide of While uranium oxides are not used in commercially made batteries, the way in which uranium oxides can reversibly insert cations is the same as the way in which the cathode in many lithium-ion cells work.

Advantages and disadvantages

Advantages

Lithium-ion batteries can be formed into a wide variety of shapes and sizes so as to efficiently fill available space in the devices they power.

Li-ion batteries are lighter than other equivalent secondary batteries—often much lighter. See also Rechargeable electricity storage system A rechargeable battery, also known as a storage battery, is a group of two or more secondary The energy is stored in these batteries through the movement of lithium ions. Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge However, the bulk of the electrodes are effectively "housing" for the ions and add weight, and in addition "dead weight" from the electrolyte, current collectors, casing, electronics and conductivity additives reduce the charge per unit mass to little more than that of other rechargeable batteries. A key advantage of using Li-ion chemistry is the high open circuit voltage that can be obtained in comparison to aqueous batteries (such as lead acid, nickel metal hydride and nickel cadmium). Open-circuit voltage or OCV is the difference of electrical potential between two terminals of a device when there is no external load connected i A wet cell is a galvanic Electrochemical cell with a liquid Electrolyte. Lead-acid batteries, invented in 1859 by French Physicist Gaston Planté, are the oldest type of Rechargeable battery. A nickel-metal hydride battery, abbreviated NiMH, is a type of Rechargeable battery similar to a nickel-cadmium ( Ni[[Cadmium Cd]] battery The nickel-cadmium battery (commonly abbreviated NiCd and ˈnɑɪˌkæd "nye-cad" is a type of Rechargeable battery using Nickel oxide hydroxide

Li-ion batteries do not suffer from the memory effect. Memory effect, also known as lazy battery effect or battery memory, is an effect observed in nickel cadmium Rechargeable batteries that causes them to They also have a low self-discharge rate of approximately 5% per month, compared with over 30% per month in common nickel metal hydride batteries (Low self-discharge NiMH batteries have much lower values, around 1. A nickel-metal hydride battery, abbreviated NiMH, is a type of Rechargeable battery similar to a nickel-cadmium ( Ni[[Cadmium Cd]] battery The low self-discharge NiMH battery ( LSD NiMH) was introduced in November 2005. 25% per month; they can still hold 85% of their charge, after one year) and 10% per month in nickel cadmium batteries. The nickel-cadmium battery (commonly abbreviated NiCd and ˈnɑɪˌkæd "nye-cad" is a type of Rechargeable battery using Nickel oxide hydroxide

According to one manufacturer, Li-ion cells (and, accordingly, "dumb" Li-ion batteries) do not have any self-discharge in the usual meaning of this word. Self-discharge is a phenomenon in batteries in which internal chemical reactions reduce the stored charge of the battery without any connection between the electrodes ^[12] What looks like a self-discharge in these batteries is a permanent loss of capacity, described in more detail below. On the other hand, "smart" Li-ion batteries do self-discharge, due to the small constant drain of the built-in voltage monitoring circuit. This drain is the most important source of self-discharge in these batteries.

Disadvantages

A unique drawback of the Li-ion battery is that its life span is dependent upon aging from time of manufacturing (shelf life) regardless of whether it was charged, and not just on the number of charge/discharge cycles. So an older battery will not last as long as a new battery due solely to its age, unlike other batteries. This drawback is not widely published. ^[15]

At a 100% charge level, a typical Li-ion laptop battery that is full most of the time at 25 degrees Celsius or 77 degrees Fahrenheit will irreversibly lose approximately 20% capacity per year. A laptop computer, also known as a notebook computer, is a small Personal computer designed for mobile use. The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 However, a battery stored inside a poorly ventilated laptop may be subject to a prolonged exposure to much higher temperatures than 25 °C, which will significantly shorten its life. The capacity loss begins from the time the battery was manufactured, and occurs even when the battery is unused. Different storage temperatures produce different loss results: 6% loss at 0 °C (32 °F), 20% at 25 °C (77 °F), and 35% at 40 °C (104 °F). When stored at 40% - 60% charge level, these figures are reduced to 2%, 4%, 15% at 0, 25 and 40 degrees Celsius respectively.

Under certain temperature conditions, the batteries have a tendency to become damaged and can sometimes never fully recharge again. In certain situations where the temperature is too cold (below the recommended battery temperature) the battery will still hold its charge but cannot be recharged as a result of the cold temperature. This is most common in smaller batteries such as cellular phones and handheld devices.

As batteries age, their internal resistance rises. This causes the voltage at the terminals to drop under load, reducing the maximum current that can be drawn from them. Eventually they reach a point at which the battery can no longer operate the equipment it is installed in for an adequate period.

High drain applications such as powertools may require the battery to be able to supply a current of (15 h^-1)C - 15/hour times "C" - the battery capacity in Ampere hours, whereas MP3 players may only require (0. An ampere-hour (symbol A h or A·h, sometimes abbreviated as Ah) is a unit of Electric charge. MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a Digital audio encoding format using a form of Lossy data compression 1 h^-1)C (discharging in 10 hours). With similar technology, the MP3 battery can tolerate a much higher internal resistance, so will have an effective life of many more cycles. ^[16]

Li-ion batteries can even go into a state that is known as deep discharge. At this point, the battery may take a very long time to recharge. For example, a laptop battery that normally charges fully in 3 hours may take up to 42 hours to recharge. Or the deep discharge state may be so severe that the battery will never come back to life. Deep discharging only takes place when products with rechargeable batteries are left unused for extended periods of time (often 2 or more years) or when they are fully discharged so often that they can no longer hold a charge. This makes Li-ion batteries unsuitable for back-up applications where they may become completely discharged.

A stand-alone Li-ion cell must never be discharged below a certain voltage to avoid irreversible damage. Therefore all Li-ion battery systems are equipped with a circuit that shuts down the system when the battery is discharged below the predefined threshold. ^[12] It should thus be impossible to "deep discharge" the battery in a properly designed system during normal use. This is also one of the reasons Li-ion cells are rarely sold as such to consumers, but only as finished batteries designed to fit a particular system.

When the voltage monitoring circuit is built inside the battery (a so-called "smart" battery) rather than the equipment, it continuously draws a small current from the battery even when the battery is not in use; furthermore, the battery must not be stored fully discharged for prolonged periods of time, to avoid damage due to deep discharge.

Li-ion batteries are not as durable as nickel metal hydride or nickel-cadmium designs and can be extremely dangerous if mistreated. A nickel-metal hydride battery, abbreviated NiMH, is a type of Rechargeable battery similar to a nickel-cadmium ( Ni[[Cadmium Cd]] battery The nickel-cadmium battery (commonly abbreviated NiCd and ˈnɑɪˌkæd "nye-cad" is a type of Rechargeable battery using Nickel oxide hydroxide They are usually more expensive.

Li-ion chemistry is not as safe as nickel metal hydride or nickel-cadmium, and a Li-ion cell requires several mandatory safety devices to be built in before it can be considered safe for use outside of a laboratory. A nickel-metal hydride battery, abbreviated NiMH, is a type of Rechargeable battery similar to a nickel-cadmium ( Ni[[Cadmium Cd]] battery The nickel-cadmium battery (commonly abbreviated NiCd and ˈnɑɪˌkæd "nye-cad" is a type of Rechargeable battery using Nickel oxide hydroxide These are: shut-down separator (for overtemperature), tear-away tab (for internal pressure), vent (pressure relief), and thermal interrupt (overcurrent/overcharging). ^[12] The devices take away useful space inside the cells, and add an additional layer of unreliability. Typically, their action is to permanently and irreversibly disable the cell.

Approximately 1% of Li-ion batteries are the subject of recalls. ^[17] .

The number of safety features can be compared with that of a nickel metal hydride cell, which only has a hydrogen/oxygen recombination device (preventing damage due to mild overcharging) and a back-up pressure valve. A nickel-metal hydride battery, abbreviated NiMH, is a type of Rechargeable battery similar to a nickel-cadmium ( Ni[[Cadmium Cd]] battery

Specifications and design

A lithium-ion battery from a mobile phone.

• Specific energy density: 150 to 200 Wh/kg (540 to 720 kJ/kg)
• Volumetric energy density: 250 to 530 Wh/l (900 to 1900 J/cm³)
• Specific power density: 300 to 1500 W/kg (@ 20 seconds^[18] and 285 Wh/l)

Because lithium-ion batteries can have a variety of cathode and anode materials, cell specifications, such as the energy density and voltage vary from chemistry to chemistry. The joule (written in lower case ˈdʒuːl or /ˈdʒaʊl/ (symbol J) is the SI unit of Energy measuring heat, Electricity

Lithium ion batteries with a lithium iron phosphate cathode and graphite anode have a nominal open-circuit voltage of 3. Open-circuit voltage or OCV is the difference of electrical potential between two terminals of a device when there is no external load connected i 6 V and a typical charging voltage of 4. The volt (symbol V) is the SI derived unit of electric Potential difference or Electromotive force. 2 V. The charging procedure is done at constant voltage with current limiting circuitry. This means charging with constant current until a voltage of 4. 2 V is reached by the cell and continuing with a constant voltage applied until the current drops close to zero. Typically the charge is terminated at 7% of the initial charge current. In the past, lithium-ion batteries could not be fast-charged and typically needed at least two hours to fully charge. Current generation cells can be fully charged in 45 minutes or less; some Lithium-Ion variants can reach 90% in as little as 10 minutes. ^[19]

Commercialization of Lithium Ion Batteries

Lithium Cobalt Oxide Cathodes

Lithium ion batteries were first commercialized by Sony in 1991. ^[20] The cells utilized a lithium cobalt oxide cathode and a graphite anode. The Mineral graphite, as with Diamond and Fullerene, is one of the Allotropes of carbon. Sony and Sanyo are the leading producers of lithium ion batteries. ^[21][22] A variety of Chinese, Japanese, and South Korean companies produce cells based on the lithium cobalt oxide cathode chemistry. ^[23]

Manganese Spinel Cathodes

LG, which is the third largest producer of lithium ion batteries, uses the lithium manganese spinel for its cathode. LG Chem Ltd ( Hangul: 엘지화학 LG화학) often referred to as LG Chemical is the largest Korean Chemical company and is headquartered in It is working with its subsidiary CPI to commercialize lithium ion batteries containing manganese spinel for HEV applications. CPI redirects here For other uses see CPI (disambiguation. A consumer price index ( CPI) is a measure of the average price of consumer A hybrid electric vehicle (HEV is a Hybrid vehicle which combines a conventional propulsion system with a Rechargeable energy storage system (RESS ^[24] Several other companies are also working on manganese spinel, including NEC and Samsung. is a Japanese multinational IT company headquartered in Minato Tokyo, Japan. The Samsung Group ( Korean:, Samsung Guerup) is South Korea 's largest company or Chaebol and the world's largest conglomerate ^[25]

Lithium Iron Phosphate Cathodes

The University of Texas first licensed its patent for lithium iron phosphate cathodes to HydroQuebec. Hydro-Québec is a Crown corporation that provides electricity to Quebec, Canada and the north-eastern parts of the United States ^[26] Phostech was later spun-off from Hydroquebec for the sole development of lithium iron phosphate. Hydro-Québec is a Crown corporation that provides electricity to Quebec, Canada and the north-eastern parts of the United States

Valence Technology, located in Austin, TX, is also working on lithium iron phosphate cells. Valence Technology Inc sells various types of Phosphate -based Lithium-ion rechargeable batteries, including N-Charge and U-Charge and has recently Since March 2005, the Segway Personal Transporter has been shipping with extended-range lithium-ion batteries^[27] made by Valence Technology using iron phosphate cathode materials. The Segway PT is a two-wheeled, self-balancing Electric vehicle invented by Dean Kamen. Segway, Inc. chose to build their large-format battery with this cathode material because of its improved safety over metal-oxide materials.

In November 2005, A123Systems announced^[28] the development of lithium iron phosphate cells based on research licensed from MIT. A123Systems is a supplier of high-power Lithium-Ion batteries ^[29][30] While the battery has slightly lower energy density that other competing Lithium Ion technologies, a 2 Ahr cell can provide a peak of 70 Amps without damage and operate at temperatures above 60 degrees C. Their first cell is in production (1Q/2006) and being used in consumer products including DeWalt power tools, aviation products, automotive hybrid systems and PHEV conversions. DeWalt is a world-wide brand of Power tools for the Construction and Woodworking industries A plug-in hybrid electric vehicle ( PHEV) is a Hybrid vehicle with batteries that can be recharged by connecting a plug to an Electric power

Titanate Anodes

Altairnano, a small firm based in Reno, Nevada, has announced a nano-sized titanate electrode material for lithium-ion batteries. Altair Nanotechnologies is a Reno Nevada -based research company that develops Nanotechnology -based solutions for energy storage and the life sciences Titanic acid refers to the Chemical compound with the formula H2TiO3 An electrode is an Electrical conductor used to make contact with a nonmetallic part of a circuit (e It is claimed the prototype battery has three times the power output of existing batteries and can be fully charged in six minutes. However the energy capacity is about half that of normal li-ion cells. The company also says the battery can handle approximately 20,000 recharging cycles, so durability and battery life are much longer, estimated to be around 20 years or four times longer than regular lithium-ion batteries. The batteries can operate from -50 °C to over 75 °C and will not explode or result in thermal runaway even under severe conditions because they do not contain graphite-coated-metal anode electrode material. ^[31] The batteries are currently being tested in a new production car made by Phoenix Motorcars which was on display at the 2006 SEMA motorshow. Phoenix Motorcars is a California-based company that focuses on developing electric vehicles

Enerdel, which is jointly owned by Ener1 and Delphi, is working to commercialize cells containing a titanate anode and manganese spinel cathode. Delphi is an Automotive parts company headquartered in Troy Michigan, USA. ^[32] Although the cells show excellent thermal properties and cyclability, their low voltage may hamper commercial success. ^[33]

All these formulations involve new electrodes (anodes or cathodes). An electrode is an Electrical conductor used to make contact with a nonmetallic part of a circuit (e By increasing the effective electrode area—thus decreasing the internal resistance of the battery—the current can be increased during both use and charging. This is similar to developments in ultracapacitors. Electric double-layer capacitors, also known as supercapacitors, electrochemical double layer capacitors ( EDLCs) or ultracapacitors Therefore, the battery is capable of delivering more power (watts); however, the battery's capacity (ampere-hours) is increased only slightly. An ampere-hour (symbol A h or A·h, sometimes abbreviated as Ah) is a unit of Electric charge.

Breakthrough Research

In April 2006, a group of scientists at MIT announced a process which uses viruses to form nano-sized wires. These can be used to build ultrathin lithium-ion batteries with three times the normal energy density. ^[34]

As of June 2006, researchers in France have created nanostructured battery electrodes with several times the energy capacity, by weight and volume, of conventional electrodes. ^[35]

In the September 2007 issue of Nature, researchers from the University of Waterloo, Canada, reported a new cathode chemistry, whereby the hydroxide group in the iron phosphate cathode was replaced by fluorine. [1] The advantages seem to be two-fold. First, there is less volume change in the cathode over a charge cycle which indicates a possibility for longer battery life. Second, the chemistry allows the substitution of Sodium or a Sodium/Lithium mixture for the Lithium in the battery (hence their reference to it as an Alkali-Ion battery).

In November 2007, Subaru unveiled their concept G4e electric vehicle with a lithium vanadium oxide based lithium ion battery, promising double the energy density of a conventional lithium ion battery (lithium cobalt oxide and graphite). is the automobile manufacturing division of Japanese transportation conglomerate Fuji Heavy Industries Co Vanadium (vəˈneɪdiəm is a Chemical element that has the symbol V and Atomic number 23 [2] In the lab, Lithium vanadium oxide anodes, paired with lithium cobalt oxide cathodes, have achieved 745Wh/l, nearly three times the volumetric energy density of conventional lithium ion batteries. [3]

In December 2007, researchers at Stanford university reported creating a lithium ion battery with ten times the energy density (amount of energy available by weight) through using silicon nanowires deposited on stainless steel as the anode. A nanowire battery is a Lithium-ion battery invented by a team led by Dr The battery takes advantage of the fact that silicon can hold large amounts of lithium, and helps alleviate the longstanding problem of cracking by the small size of the wires. [4] To gain a tenfold improvement in energy density, the cathode would need to be improved as well; however, just improving the anode as such could provide "several" times the energy density, according to the team. The team leader, Yi Cui, expects to be able to commercialize the technology in about five years. [5].

Silicon nanowire lithium ion battery has a anode made out of Silicon nano wires. Having a large capacitive anode wont increase the capacity of the battery as predicted by the author when the cathode material is far less capacitive than the anode. Current Li-ion capacity is mainly limited by the capacity of the cathode materials.

Guidelines for prolonging Li-ion battery life

• Unlike Ni-Cd batteries, lithium-ion batteries should be charged early and often. The nickel-cadmium battery (commonly abbreviated NiCd and ˈnɑɪˌkæd "nye-cad" is a type of Rechargeable battery using Nickel oxide hydroxide However, if they are not used for a long time, they should be brought to a charge level of around 40% - 60%. Lithium-ion batteries should not be frequently fully discharged and recharged ("deep-cycled") like Ni-Cd batteries, but this is necessary after about every 30th recharge to recalibrate any external electronic "fuel gauge" (e. g. State Of Charge meter). This prevents the fuel gauge from showing an incorrect battery charge. ^[16]
• Li-ion batteries should never be depleted to below their minimum voltage, 2. 4v to 3. 0v per cell.
• Li-ion batteries should be kept cool. Ideally they are stored in a refrigerator. Aging will take its toll much faster at high temperatures. The high temperatures found in cars cause lithium-ion batteries to degrade rapidly.
• Li-ion batteries should not be frozen ^[36] (most lithium-ion battery electrolytes freeze at approximately −40 °C; however, this is much colder than the lowest temperature reached by household freezers).
• Li-ion batteries should be bought only when needed, because the aging process begins as soon as the battery is manufactured. ^[16]
• When using a notebook computer running from fixed line power over extended periods, the battery should be removed,^[37] and stored in a cool place so that it is not affected by the heat produced by the computer.

Storage temperature and charge

Storing a Li-ion battery at the correct temperature and charge makes all the difference in maintaining its storage capacity. The following table shows the amount of permanent capacity loss that will occur after storage at a given charge level and temperature.

It is significantly beneficial to avoid storing a lithium-ion battery at full charge. A Li-ion battery stored at 40% charge will last many times longer than one stored at 100% charge, particularly at higher temperatures. ^[16]

If a Li-ion battery is stored with too low a charge, there is a risk of allowing the charge to drop below the battery's low-voltage threshold, resulting in an unrecoverable dead battery. Once the charge has dropped to this level, recharging it can be dangerous. Some batteries therefore feature an internal safety circuit which will prevent charging in this state, and the battery will be for all practical purposes dead.

In circumstances where a second Li-ion battery is available for a given device, it is recommended that the unused battery be discharged to 40% and placed in the refrigerator to prolong its shelf life. While the battery can be used or charged immediately, some Li-ion batteries will provide more energy when brought to room temperature.

Prolonging Life in Multiple Cells Through Cell Balancing

Analog front ends that balance cells and eliminate mismatches of cells in series or parallel significantly improve battery efficiency and increase the overall pack capacity. As the number of cells and load currents increase, the potential for mismatch also increases. There are two kinds of mismatch in the pack: State-of-Charge (SOC) and capacity/energy (C/E) mismatch. Though the SOC mismatch is more common, each problem limits the pack capacity (mAh) to the capacity of the weakest cell.

It is important to recognize that the cell mismatch results more from limitations in process control and inspection than from variations inherent in the Lithium Ion chemistry. The use of cell balancing can improve the performance of series connected Li-ion Cells by addressing both SOC and C/E issues. ^[38] SOC mismatch can be remedied by balancing the cell during an initial conditioning period and subsequently only during the charge phase. C/E mismatch remedies are more difficult to implement and harder to measure and require balancing during both charge and discharge periods.

Cell Balancing

Cell balancing is defined as the application of differential currents to individual cells (or combinations of cells) in a series string. Normally, of course, cells in a series string receive identical currents. A battery pack requires additional components and circuitry to achieve cell balancing. However, the use of a fully integrated analog front end for cell balancing^[39] reduces the required external components to just balancing resistors.

This type of solution eliminates the need for discrete capacitors, diodes and most other resistors to achieve balance.

Battery pack cells are balanced when all the cells in the battery pack meet two conditions.

1. If all cells have the same capacity, then they are balanced when they have the same relative State of Charge (SOC. ) In this case, the Open Circuit Voltage (OCV) is a good measure of the SOC. If, in an out of balance pack, all cells can be differentially charged to full capacity (balanced), then they will subsequently cycle normally without any additional adjustments. This is mostly a one shot fix.

2. If the cells have different capacities, they are also considered balanced when the SOC is the same. But, since SOC is a relative measure, the absolute amount of capacity for each cell is different. To keep the cells with different capacities at the same SOC, cell balancing must provide differential amounts of current to cells in the series string during both charge and discharge on every cycle.

Safety

Lithium-ion batteries can rupture, ignite, or explode when exposed to high temperature environments, for example in an area that is prone to prolonged direct sunlight. ^[40] Short-circuiting a Li-ion battery can cause it to ignite or explode, and as such, any attempt to open or modify a Li-ion battery's casing or circuitry is dangerous. Li-ion batteries contain safety devices that protect the cells inside from abuse, and, if damaged, can cause the battery to ignite or explode.

Contaminants inside the cells can defeat these safety devices. For example, the mid-2006 recall of approximately 10 million Sony batteries used in Dell, Sony, Apple, Lenovo/IBM, Panasonic, Toshiba, Hitachi, Fujitsu and Sharp laptops was stated to be as a consequence of internal contamination with metal particles. The multinational technology company Dell Inc develops manufactures sells and supports Personal computers and other computer-related products is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics Lenovo Group Limited (,) is China's largest and the world's fourth largest Personal computer manufacturer after Hewlett-Packard and Dell of the U International Business Machines Corporation abbreviated IBM and nicknamed "Big Blue", is a multinational Computer Technology ( is a multinational conglomerate manufacturing company headquartered in Tokyo, Japan. () is a Multinational corporation specializing in high-technology and services headquartered in Marunouchi Itchome Chiyoda, Tokyo, Japan. is a Japanese company specializing in Semiconductors Computers ( Supercomputers Personal computers, servers, Telecommunications () is a Japanese Electronics manufacturer founded in 1912 It takes its name from one of its founder's first inventions the Ever-Sharp Mechanical pencil, which Under some circumstances, these can pierce the separator, causing the cell to short, rapidly converting all of the energy in the cell to heat resulting in an exothermic oxidizing reaction, increasing the temperature to a few hundred degrees Celsius in a fraction of a second. ^[41] This causes the neighboring cells to heat up, causing a chain thermal reaction.

The mid-2006 Sony laptop battery recall was not the first of its kind, however it was the largest to date. During the past decade there have been numerous recalls of lithium-ion batteries in cellular phones and laptops owing to overheating problems. In October 2004, Kyocera Wireless recalled approximately 1 million batteries used in cellular phones, due to counterfeit batteries produced in Kyocera's name. Kyocera Wireless Corporation ( KWC) is a manufacturer of mobile telephones for CDMA networks and is a wholly owned subsidiary of Kyocera Corporation ^[42] In December 2006, Dell recalled approximately 22,000 batteries from the U. The multinational technology company Dell Inc develops manufactures sells and supports Personal computers and other computer-related products S. market. ^[43] In March 2007, Lenovo recalled approximately 205,000 9-cell lithium-ion batteries due to an explosion risk. In August 2007, Nokia recalled over 46 million lithium-ion batteries, warning that some of them might overheat and possibly explode. Nokia Corporation (pronunciation /'nɔkiɑ/),,) is a Finnish multinational Communications Corporation, headquartered ^[44] There was an incident in the Philippines involving a Nokia N91, which uses the BL-5C battery. The Philippines ( Filipino: Pilipinas, officially known as the Republic of the Philippines (fil ''Republika ng Pilipinas'' RP The Nokia N91 is a Mobile phone that was released to the public in April of 2006. ^[45]

It is possible to replace the lithium cobalt oxide cathode material in li-ion batteries with lithiated metal phosphate cathodes that are not as sensitive to temperature, and so are less prone to explode. Lithium cobalt oxide (LiCoO2 is a Chemical compound commonly used in the positive Electrodes of Lithium-ion batteries. This also extends their shelf life. Shelf life is that length of time that Food, drink Medicine and other perishable items are given before they are considered unsuitable for sale or However, currently these 'safer' li-ion batteries are mainly destined for electric cars and other large-capacity battery applications, where the safety issues are more critical. An electric car is a type of alternative fuel Car that utilizes Electric motors and Motor controllers instead of an Internal combustion engine Unfortunately, a problem with these 'safer' li-ion batteries is that lithiated metal phosphate batteries hold only about 75 percent as much energy. ^[46]

Another option is to use manganese oxide or iron phosphate cathode. Iron(III phosphate, also ferric orthophosphate, or ferric phosphate, FePO4 is a Phosphate of Iron. ^[47]

See also

• Battery balancer
• Battery holder
• Battery recycling
• Lithium battery
• Lithium iron phosphate battery - LiFePO₄
• Valence Technology

References

External links

• Charging the Lithium Ion Battery.
• How Lithium-ion Batteries Work.
• Stanford's nanowire battery holds 10 times the charge of existing ones, Stanford Report, December 18, 2007
• The Lithium Ion Battery.
• Advantages and Limitations of the Lithium Polymer Battery.