Page 122 - Toucpad robotics C11

Advantages
Lightweight: Very good power-to-weight ratio, allowing robots to carry less weight for the same energy, or perform
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tasks for longer durations.
Compact Size: High volumetric energy density means they can be made small, fitting into confined robot chassis.
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Long Cycle Life: Can withstand many charge-discharge cycles before their capacity significantly degrades (though
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this varies by chemistry).
High Efficiency: Very efficient in storing and releasing energy.
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Flexible Designs: Can be manufactured in various shapes and sizes (e.g., cylindrical, pouch, prismatic cells).
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Disadvantages
Cost: Generally more expensive to manufacture and purchase compared to Lead-acid batteries.
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Safety Concerns: Can be prone to thermal runaway (overheating leading to fire or explosion) if overcharged,
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over-discharged, physically damaged, or subjected to extreme temperatures. This requires sophisticated Battery
Management Systems (BMS) to monitor and control their operation, adding to complexity and cost.
Temperature Sensitivity: Performance and lifespan can be significantly affected by extreme hot or cold temperatures.
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Degradation Over Time: Even if not used, Lithium-ion batteries gradually lose capacity over their lifespan (calendar
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ageing).
Transportation Restrictions: Due to safety concerns, there are strict regulations for transporting large Lithium-ion
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battery packs.

Lead-Acid Batteries

Terminal Posts
Vent Caps
Cells
Cover Connectors
Cell
Partitions Cells
Case Plates

Separators
Electrolyte

Lead-acid batteries are one of the oldest and most mature rechargeable battery technologies, first invented in 1859. They
are robust, reliable, and known for their ability to deliver high surge currents.

Description and Working Principle
A Lead-acid battery consists of electrodes made of lead and lead dioxide, immersed in an electrolyte of
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sulphuric acid.
During discharge, lead on the negative electrode and lead dioxide on the positive electrode react with the sulphuric
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acid to form lead sulphate on both electrodes, while releasing electrons to the external circuit.
During charge, the external current reverses this chemical reaction, converting the lead sulphate back into lead and
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lead dioxide, and regenerating the sulphuric acid.
They are commonly available as flooded (wet cell) batteries (requiring maintenance of electrolyte levels) or sealed
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(Valve Regulated Lead-Acid - VRLA) batteries, which include Absorbent Glass Mat (AGM) and Gel Cell types
(maintenance-free).

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Touchpad Robotics - XI