Dear All,
I have built a Lithium ion pouch battery cell from NMC 111 and graphite with a specific seperator and electrolyte.
I now want to do the first steps in testing this battery cell, ie. formation, charging, discharging and calculating the actual capacity. I need to understand the different steps involved in this procedure and need access to where I can read about them - publications/websites and any other literature links would be greatly helpful.
Looking forward to your comments. Thanks!
The smallest working unit in a battery is the electrochemical cell, consisting of a cathode and an anode separated and connected by an electrolyte. The electrolyte conducts ions but is an insulator to electrons. In a charged state, the anode contains a high concentration of intercalated lithium while the cathode is depleted of lithium. During the discharge, a lithium ion leaves the anode and migrates through the electrolyte to the cathode while its associated electron is collected by the current collector to be used to power an electric device. he cell designs and combinations in modules and packs differ greatly. To establish a base understanding, this paper shows the main cell designs and then focuses on materials, processing, and manufacturing with special emphasis on batteries for transportation. The electrodes in lithium-ion cells are always solid materials. One can distinguish between cell types according to their electrolytes, which may be liquid, gel, or solid-state components. The electrolytes in gel and solid-state cells represent a structural component and do not need additional separators for the effective separation of electrodes and avoidance of short circuits. Cells come in button, cylindrical, and prismatic forms.
Cathode Materials State-of-the-art cathode materials include lithium-metal oxides [such as LiCoO2, LiMn2O4, and Li(NixMnyCoz)O2], vanadium oxides, olivines (such as LiFePO4), and rechargeable lithium oxides.
Anode Materials Anode materials are lithium, graphite, lithium-alloying materials, intermetallics, or silicon. Lithium seems to be the most straight forward material but shows problems with cycling behavior and dendritic growth, which creates short circuits. Carbonaceous anodes are the most utilized anodic material due to their low cost and availability.
Electrolytes A safe and long-lasting battery needs a robust electrolyte that can withstand existing voltage and high temperatures and that has a long shelf life while offering a high mobility for lithium ions. Types include liquid, polymer, and solid-state electrolytes. Liquid electrolytes are mostly organic, solventbased electrolytes containing LiBC4O8 (LiBOB), LiPF6, Li[PF3(C2F5)3], or similar. The most important consideration is their flammability; the bestperforming solvents have low boiling points and have flash points around 30°C. Therefore, venting or explosion of the cell and subsequently the battery pose a danger. Electrolyte decomposition and highly exothermic side reactions in lithium-ion batteries can create an effect known as “thermal runaway.” Thus, selection of an electrolyte often involves a tradeoff between flammability and electrochemical performance.
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