Unit 1 - Battery Technology

Introduction to Battery Technology

• Batteries play a crucial role in everyday devices like clocks, electric vehicles, uninterruptible power supplies (UPS), remote controls, cameras, laptops, mobile phones, medical devices, and toys.
• Different applications necessitate specific battery characteristics, such as burst power for car batteries and durable, long-lasting power for pacemakers.

Types of Batteries

• Primary Batteries:

  • Galvanic cells that generate electricity through chemical reactions sealed within.
  • Non-rechargeable and known as "throw-away" batteries.
  • Examples include dry cells and lithium copper sulfide cells.

• Secondary Batteries:

  • Rechargeable batteries enabling reversal of chemical reactions through current infusion.
  • Can sustain multiple charge-discharge cycles.
  • Common types include lead-acid batteries, nickel-cadmium cells, and lithium-ion batteries.

Requirements of Batteries

• Primary Batteries:

  • Must be lightweight, compact, and made from readily available materials.
  • Should possess high energy density and long shelf life with stable voltage during discharge.

• Secondary Batteries:

  • Require a long lifespan in both charged and discharged states and fast recharge capabilities.
  • Should maintain a high power-to-weight ratio and high energy density.

Basic Principle Behind Battery Operation

• Battery function relies on electron exchange between oxidation and reduction reactions, separated physically.
• The flow of electrons through a load generates electric current, driven by electrochemical potential, which relates to battery voltage.

Components of a Battery

• Composed of electrodes (anode and cathode), electrolyte, and connectors for electron transfer.
• The choice of materials for electrodes and electrolytes greatly affects battery performance.

Electrode Functions

• Anode: Site of oxidation, providing electrons (negative).
• Cathode: Site of reduction, receiving electrons (positive).

Battery Definition and Function

• Batteries store energy chemically and convert it to electrical energy via electrochemical reactions.
• Electrons flow from one electrode through an external circuit while ions move through the electrolyte to maintain neutrality.

Battery Structure

• Comprises electrochemical cells with a pair of electrodes separated by an electrolyte.
• Separators improve mechanical strength and prevent short circuits.

Current Collectors

• Made from thin aluminum or copper foils to optimize electron flow and heat dissipation.

Requirements for Electrodes

• Cathode:

  • Should have high redox potential, specific capacity, stability, and reversibility.

• Anode:

  • Requires low redox potential, high specific capacity, and efficient conductivity.

Cell Potential

• Defined as the voltage difference between cathode and anode:
  • ( E_{cell} = E_{cathode} − E_{anode} )
• A larger difference correlates with higher voltage in the battery.

Electrolytes and Redox Reactions

• Electrolytes can be liquid, solid, polymer, or hybrid that facilitate ionic movement.
• Essential for maintaining ion transport between electrodes during operation.

Explore the fundamentals of battery technology in this quiz. From clocks to cars, discover how different batteries are designed for various applications based on their specific properties. Test your knowledge on the types and functions of batteries essential in everyday life.