IEEE 1679.1:2017 pdf free download – IEEE Guide for the Characterization and Evaluation of Lithium-Based Batteries in Stationary Applications
5.1 General
Refer to Clause 5 of IEEE Std 1679-2010. This clause describes the main lithium-based technologies thatare either used or are being considered for stationary battery applications. These include lithium-ion (Li-ion), lithium-ion polymer (LiPo), lithium-metal polymer (LMP) and lithium-sulfur(Li-S).
Lithium-based batteries use lithium metal or some other source of lithium ions in the negative electrode.During the battery discharge, the lithium ions travel to the positive electrode, which can be one of variousmaterials，including a transition metal oxide, a transition metal phosphate, a sulfur compound,or evenoxygen in the atmosphere or water. The electrolyte is typically a conductive salt in an organic liquidsolution, or a conductive polymer.
The information provided in this clause relates predominantly to Li-ion technology, as this technology is byfar the most widely used. Differences between Li-ion and other lithium battery technologies are highlightedwhere appropriate.
Lithium-based batteries typically comprise cells and associated management systems. In many cases thesebatteries are assembled by the cell manufacturer, and in others an integrator assembles cells from a thirdparty with the integrator’s management systems. In both cases, the provider is referred to in this documentas the manufacturer.
5.2 Storage medium
5.2.1 General
Li-ion batteries are the most common lithium-based battery type, and include a wide range of chemistriesthat all operate in the same general manner. The traditional Li-ion battery has a negative electrode(commonly referred to as the anode), typically a layered carbon; a positive electrode(cathode), typically alithiated metal oxide or lithiated metal phosphate; and an electrolyte containing a lithium salt in an organicsolvent. On discharge, lithium ions flow from between the carbon layers in the negative to the oxide layersin the positive.On charge,the lithium ions flow in reverse,moving back into the carbon layers. Thisprocess is known as intercalation and referred to colloquially as a ‘rocking chair’reaction.
Figure I shows a representation of the Li-ion reaction mechanism for a typical chemistry with metal oxidepositive and carbon (graphite) negative materials.
During manufacturing, the first charge of a lithium-based cell forms a passivation layer,known as thesolid-electrolyte interphase (SEI) on the surface of the negative electrode.This layer prevents anuncontrolled reaction between the clectrolyte and lithium ions in the negative material, and its stability iscritical for the life and safety of lithium-based cells (see 6.3).One exception to this principle is LTonegative material, which has an electrode potential that is sufficiently high that the material is stable withrespect to the clectrolyte and does not form an SEL.
LiPo is a variant of the lithium-ion battery. LiPo batteries usce similar materials to Li-ion,with the maindifference being that the electrolyte is immobilized in a polymer matrix that also binds the electrodestogether and allows for flexibility in cell geometry (see 5.4.2.1).
LMP technology uses a lithium metal alloy as the negative and a metal oxide or phosphatc positive. Theelectrolyte is an ionically conductive solid polymer that may operate at a slightly elevated temperature(e.g.,40 °C to 60 °C) to improve its conductivity. LMP continues to be the subject of ongoing rescarch anddevelopment and, at the time of publication of this document, one company was in commercial productionof LMP batteries and at least two others were working to bring variants of LMP technology to market.