Energy Storage Systems Overview

  • Introduction to Energy Storage Systems

  • Energy storage is essential in many areas of life, enabling separation of energy production and consumption in time and space.

  • Key focus areas include:

    • Basic applications of energy storage (Section 2.2)
    • Different applications (Section 2.3) including:
    • Mobile applications (e.g., vehicles)
    • Stationary systems linked to power grids

  • What Storage is Used For

  • Nature's principle of storage:

    • Plants store water; animals store food or energy reserves.
    • Humans store assets and fuel supplies (e.g., filling gas tanks).

  • The primary goal of storage:

    • To utilize surplus energy at future times when shortages occur.

  • Energy vs. Power

  • Energy denotes how much power can be added or extracted from a system.

  • Example Calculation:

    • For a phone with a 24 Wh initial charge, charged at 15W for 8 hours, and discharged at 10W for 12 hours:
    • Final energy (E(T)) = 24 Wh + (8h x 15W) - (12h x 10W) = 24 Wh

  • Types of energies:

    • Electrical, mechanical, and thermal energy dissected in Section 2.2.1.

  • Efficiency and Transformation Costs

  • Energy forms: mechanical, electrical, and thermal.

  • Transformations can be categorized by:

    • Efficiency (η) defined as output/input energy ratio (η = Eout/Ein).

  • Importance for design:

    • Higher losses imply that design decisions should take these efficiencies into account.

  • Applications of Energy Storage Systems

  • Mobile Applications

    • Examples: smartphones, laptops, power tools (e.g., cordless drills).
    • Increased demand for portability requires balancing storage capacity, weight, and cost.
    • Power demands vary widely across applications with mobile tools requiring high short-duration power (up to 2000W).

  • E-Mobility and Mobile Machinery

    • Storage systems required in vehicles for transporting payloads or performing functions (e.g., construction machinery).
    • Powertrain configurations are influenced by efficiency and energy sources (internal combustion vs. electric).
    • Example challenges and design considerations for electric and hybrid vehicles:
    • Recovery of energy during braking and acceleration impacts energy management decisions.

  • Stationary Applications

    • Applications include household energy storage for grid-connected or off-grid systems, capturing surplus energy for future use.
    • Energy storage in this context serves as a buffer to smooth out supply/demand mismatches.
    • Devices include heat storage, storage batteries linked to renewable energy sources.

  • Characteristics of Storage Applications

  • Applications categorized using:

    • Energy demand
    • Power demand
    • E-Rate (ratio of power demand to energy stored) helps classify applications as either power or energy focused.

  • Example:

    • E-Rates help differentiate between applications—higher for tools needing bursts of power, lower for devices like phones relying on prolonged usage.

  • Conclusion and Summary of Key Points

  • Energy storage systems are crucial for effectively managing energy in modern society.

  • Utilize a clear understanding of energy and power demands along with E-Rates for tailoring applications to needed specifications.

  • Recognize that losses occur during energy transformations, underscoring the importance of system efficiency for practical applications.