|It was not until the early 1970s that the first non-rechargeable lithium batteries became commercially available. Attempts to develop rechargeable lithium batteries followed in the 1980s but the endeavor failed because of instabilities in the metallic lithium used as anode material.|
Lithium is the lightest of all metals, has the greatest electrochemical potential and provides the largest specific energy per weight. Rechargeable batteries with lithium metal on the anode (negative electrodes) could provide extraordinarily high energy densities, however, cycling produced unwanted dendrites on the anode that could penetrate the separator and cause an electrical short. The cell temperature would rise quickly and approaches the melting point of lithium, causing thermal runaway, also known as “venting with flame.”
The inherent instability of lithium metal, especially during charging, shifted research to a non-metallic solution using lithium ions. Although lower in specific energy than lithium-metal, Li-ion is safe, provided cell manufacturers and battery packers follow safety measures in keeping voltage and currents to secure levels. In 1991, Sony commercialized the first Li-ion battery, and today this chemistry has become the most promising and fastest growing on the market. Meanwhile, research continues to develop a safe metallic lithium battery in the hope to make it safe.
In 1994, it cost more than $10 to manufacture Li-ion in the 18650* cylindrical cell delivering a capacity of 1,100mAh. In 2001, the price dropped to $2 and the capacity rose to 1,900mAh. Today, high energy-dense 18650 cells deliver over 3,000mAh and the costs have dropped further. Cost reduction, increase in specific energy and the absence of toxic material paved the road to make Li-ion the universally acceptable battery for portable application, first in the consumer industry and now increasingly also in heavy industry, including electric powertrains for vehicles.
In 2009, roughly 38 percent of all batteries by revenue were Li-ion. Li-ion is a low-maintenance battery, an advantage many other chemistries cannot claim. The battery has no memory and does not need exercising to keep in shape. Self-discharge is less than half compared to nickel-based systems. This makes Li-ion well suited for fuel gauge applications. The nominal cell voltage of 3.6V can power cell phones and digital cameras directly, offering simplifications and cost reductions over multi-cell designs. The drawback has been the high price, but this leveling out, especially in the consumer market.
Types of Lithium-ion Batteries
|SpecificationsLi-cobaltLi-manganeseLi-phosphateNMC 1Voltage3.60V3.70V3.30V3.60/3.70VCharge limit4.20V4.20V3.60V4.20VCycle life 2500500–1,0001,000–2,0001,000–2,000Operating temperatureAverageAverageGoodGoodSpecific energy150–190Wh/kg100–135Wh/kg90–120Wh/kg140Wh/kgSpecific power1C10C, 40C pulse35C continuous10CSafetyAverage. Requires protection circuit and cell balancing of multi cell pack. Requirements for small formats with 1 or 2 cells can be relaxedVery good, needs cell balancing and V protectionGood, needs cell balancingand voltage protectionThermal runaway 3150°C(302°F)250°C(482°F)270°C(518°F)210°C(410°F)CostRaw material highMaterial 30% less than cobaltHighHighIn use since1994200219992003Researchers, manufacturersSony, Sanyo, FDK, SaftNEC, Samsung, HitachiUT, QH, MIT A123, ValenceSony, Sanyo, Nissan MotorNotesVery high specific energy, limited power; for cell phones, laptopsHigh power, average to high specific energy, power tools, medical, EVsHigh power, average specific energy, higher self-discharge than other Li-ionVery high specific energy, high power; tools, medical, EVs|
|Table 2: Characteristics of the four most commonly used lithium-ion batteries|
|1NMC, NCM, CMN, CNM, MNC and MCN are basically the same. The stoichiometry is usually Li[Ni(1/3)Co(1/3)Mn(1/3)]O2. The order of Ni, Mn and Co does not matter much.2Application and environment govern cycle life; the numbers do not always apply correctly.3A fully charged battery raises the thermal runaway temperature, a partial charge lowers it.|
* Standard of a cylindrical Li-ion cell developed in the mid 1990s; measures 18mm in diamter and 65mm in length; commonly used for laptops.
** Some Lithium Nickel Manganese Cobalt Oxide systems go by designation of NCM, CMN, CNM, MNC and MCN. The systems are basically the same.
- Aug 14, 2017-