Cells, in the context of batteries, are charged by connecting their negative electrode to the negative terminal of a charger and their positive electrode to the positive terminal. This establishes a current flow from the positive terminal of the charger, through the cell, to the negative terminal. The equation V = E + Ir describes this process, where V is the voltage across the cell, E is the cell's electromotive force (EMF), I is the current, and r is the internal resistance of the cell.
Different types of cells utilize different charging mechanisms. For example:
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Lithium-ion batteries, commonly found in cell phones and laptops, utilize a chemical process involving the movement of lithium ions between the positive and negative electrodes during charge and discharge. [Source: https://www.energy.gov/energysaver/articles/how-lithium-ion-batteries-work]
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Fuel cells, like those used in some electric vehicles, generate electricity through a chemical reaction between hydrogen and oxygen, rather than relying solely on a battery for power storage. [Source: https://afdc.energy.gov/vehicles/how-do-fuel-cell-electric-cars-work]
The charging method impacts battery life. For instance, constant voltage charging protocols can lead to increased capacity fade in some battery types. [Source: https://www.sciencedirect.com/science/article/pii/S0378775303000272]
While the above focuses on charging batteries, it's important to note that "cells" can also refer to biological cells. In this context, the term "charging" is different. For instance, research explores the effects of charged particles on biological cells, for example in cancer treatment using particle therapy [Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC4751258/], or studies on how charged particles interact with DNA within cells. [Source: https://pubmed.ncbi.nlm.nih.gov/16484153/] In this biological context, "charging" doesn't refer to electrical charging in the same manner as batteries.
In summary, the method of charging a cell depends heavily on the type of cell. Batteries are charged by connecting them to a power source with the correct polarity, while the term "charging" for biological cells refers to a different process altogether.
