A.
First of all, a cell is a single encased electrochemical unit, which exhibits a voltage differential across its two terminals. A battery is one or more cells which are electrically connected together by permanent means. There could be a battery with only one cell. Following is a recap of the limits of lithium contents of items carried by passenger and crew.

2.3.2.4 Wheel chairs with lithium batteries: There is no limit to the batteries/cells.
2.3.2.6 Security type equipment with lithium batteries: Subparagraph (c) stipulates the limit of cells and batteries.
2.3.3.2 Lithium ion batteries: More than 100Wh, but not to exceed 160Wh. Needless to mention, the aggregate amount of lithium in all the cells must not exceed 160Wh.
2.3.4.8 Portable medical electronic devices: Lithium metal batteries not to exceed 8g. Lithium ion batteries not to exceed 160Wh. Needless to mention, the aggregate amount of lithium in all the cells must be within 8g for metal and 160Wh for ion cells.
2.3.5.9 Portable electronic devices: Including spares, Lithium metal batteries not to exceed 2g, and Lithium ion batteries not to exceed 100Wh. Needless to mention, the aggregate amount of lithium in all the cells must be within 2g for metal and 100Wh for ion cells.