LITHIUM ION BATTERY PORTABLE

Silicon achieves a 20 to 30 percent increase in specific energy at the cost of lower load currents and reduced cycle life. Developments also occur on the anode and several additives are being tried, including silicon-based alloys. Sony’s original lithium-ion battery used coke as the anode (coal product), and since 1997 most Li-ion batteries use graphite to attain a flatter discharge curve. Common cathode material are Lithium Cobalt Oxide (or Lithium Cobaltate), Lithium Manganese Oxide (also known as spinel or Lithium Manganate), Lithium Iron Phosphate, as well as Lithium Nickel Manganese Cobalt (or NMC)** and Lithium Nickel Cobalt Aluminum Oxide (or NCA). For the last 10 years or so, the cathode has characterized the Li-ion battery. Charge reverses the movement.Īll materials in a battery possess a theoretical specific energy, and the key to high capacity and superior power delivery lies primarily in the cathode. On discharge, the anode undergoes oxidation, or loss of electrons, and the cathode sees a reduction, or a gain of electrons. When the cell charges and discharges, ions shuttle between cathode (positive electrode) and anode (negative electrode).

Figure 1 illustrates the process.įigure 1: Ion flow in lithium-ion battery During discharge, the ions flow from the anode to the cathode through the electrolyte and separator charge reverses the direction and the ions flow from the cathode to the anode. The cathode is a metal oxide and the anode consists of porous carbon. Types of Lithium-ion Batteries Similar to the lead- and nickel-based architecture, lithium-ion uses a cathode (positive electrode), an anode (negative electrode) and electrolyte as conductor. The drawback has been the high price, but this leveling out, especially in the consumer market. The nominal cell voltage of 3.6V can power cell phones and digital cameras directly, offering simplifications and cost reductions over multi-cell designs. This makes Li-ion well suited for fuel gauge applications.

Self-discharge is less than half compared to nickel-based systems. The battery has no memory and does not need exercising to keep in shape. Li-ion is a low-maintenance battery, an advantage many other chemistries cannot claim. In 2009, roughly 38 percent of all batteries by revenue were Li-ion.

LITHIUM ION BATTERY PORTABLE

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. Today, high energy-dense 18650 cells deliver over 3,000mAh and the costs have dropped further. In 2001, the price dropped to $2 and the capacity rose to 1,900mAh. In 1994, it cost more than $10 to manufacture Li-ion in the 18650* cylindrical cell delivering a capacity of 1,100mAh. Meanwhile, research continues to develop a safe metallic lithium battery in the hope to make it safe. In 1991, Sony commercialized the first Li-ion battery, and today this chemistry has become the most promising and fastest growing on the market. 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. The inherent instability of lithium metal, especially during charging, shifted research to a non-metallic solution using lithium ions. The cell temperature would rise quickly and approaches the melting point of lithium, causing thermal runaway, also known as “venting with flame.” 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. Lithium is the lightest of all metals, has the greatest electrochemical potential and provides the largest specific energy per weight. 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. It was not until the early 1970s that the first non-rechargeable lithium batteries became commercially available. Please read our new ' Lithium-based Batteries' for an updated version.

Lithium ion battery