310102h Cells and batteries 2025 (TF) (2)

Overview of Cells & Batteries

• Cells and batteries are vital components used in various industries, including automotive, commercial, and electronics.

• Understanding their construction, operation, and applications is crucial for maintenance and replacement tasks.

• The global market for batteries is projected to grow significantly from $112 billion in 2021 to nearly $424 billion by 2030.

Objectives

1. Define basic terminology related to cells and batteries.

2. Describe construction and operation of basic primary cells.

3. Explain the types and operation of lead-acid batteries.

4. Discuss nickel-cadmium (NiCd) battery construction and operation.

5. Explain lithium battery construction and operation.

6. Identify hazards and precautions when charging batteries.

7. Understand common battery performance ratings.

8. Analyze the effects of battery internal resistance.

Historical Context

• First Battery:

  • Created by Alessandro Volta in 1800, called the voltaic pile.

  • Constructed with alternating layers of zinc, moist blotting paper, and silver.

  • Voltage and current can be measured across the top and bottom by attaching wires.

Definitions

What is a Cell?

• A device that converts chemical energy into electrical energy.

• Schematic symbols illustrate different types of cells.

What is a Battery?

• Composed of multiple cells connected in series to achieve higher voltages.

• Example: For cells of 1.5V, 6 cells yield 9V (6 x 1.5V).

Battery & Cell Polarities

• Meter readings on battery terminals can vary based on connections.

• Example voltages:

  • 4 cells yield 6V if each cell is 1.5V (4 x 1.5V).

  • Paralleled batteries increase output current without increasing voltage.

Electrode and Electrolyte Effects

• The energy output is influenced by electrode materials and electrolyte type.

• Larger electrode areas increase energy capacity and current output over various durations.

Primary Cells and Batteries

• Defined as non-rechargeable, designed for light-duty and single-use applications.

• Proper disposal is crucial.

The Leclanché Cell

• Invented by Georges Leclanché in 1866.

• Contains an ammonium chloride electrolyte, manganese dioxide cathode, and zinc anode, generating 1.5V.

• Modern versions include carbon rods and zinc canisters, referred to as dry cells.

Examples of Primary Cell Types

• Alkaline Cells:

  • Used widely and found in sizes like AAA, AA, C, and D.

  • Higher capacity than Leclanché cells thanks to improved materials.

• Lithium Cells:

  • Commonly used in compact electronics, producing 3.0V as seen in wristwatches and calculators.

Secondary Cells and Batteries

• Rechargeable options that can restore full capacity.

• Three types of lead-acid cells:

  1. Flooded Lead Acid

  2. Gelled Electrolyte Acid

  3. Absorptive Glass Mat (AGM)

Lead-Acid Batteries

• Oldest rechargeable batteries, first developed in 1859, commonly used in vehicles.

• Advantages: Low initial cost and reliability.

• Disadvantages: Efficiency drops in cold temperatures; corrosive electrolyte; risk of explosive gases during recharging; need regular maintenance.

State of Charge Measurements

• Monitored using specific gravity (SG) and voltage readings.

• Example indicates 100% charge with 1.265 SG and 12.7V.

Common Battery Hazards

• Sulfation: Occurs if SG falls below 1.225 or voltage drops below specified levels, impeding battery performance.

Lead-Acid Battery Types

Flooded Cells

• Produce approximately 2 to 2.1V per cell with 6 cells forming a standard 12V battery.

Gelled Electrolyte and AGM

• Maintenance-free, operate without leaks, and can be used in any position.

• Suitable for high-output applications such as UPS systems.

Nickel-Cadmium (NiCd) Batteries

• Constructed from nickel hydroxide and cadmium hydroxide, operating at 1.2V.

• Known for consistent voltage throughout discharge cycles and high current capabilities.

• Advantages include rapid recharging, long shelf life, and resistance to temperature variations.

Lithium Batteries

• Rechargeable lithium polymer batteries produce 3.7V for portable electronics.

Testing Batteries

Load Testing

• Evaluates battery performance by drawing amperes similar to real-world usage.

• Must be conducted on a near full charge.

Amp-Hour Rating

• Indicates the energy capacity of batteries (e.g., 90A can sustain various currents for specific hours).

Internal Resistance

• Influences terminal voltage as load is applied.

• Calculations for internal resistance can utilize open circuit voltage, load measurements, and resistance values.