Battery Storage Lab
Classroom worksheet · Interactive simulation: https://lkforge.com/tools/physics/battery/
Name: Date:
Learning objectives
- Describe how a battery stores and releases energy.
- Relate capacity, charge, and discharge.
- Define round-trip efficiency.
Variables to change
- Charge/discharge rate (C-rate)
- Capacity
- State of charge
Procedure
- Charge the battery and watch the state of charge rise.
- Discharge it under load and watch it fall.
- Compare energy put in during charging with energy delivered on discharge.
Observations
Record energy in vs energy out, and how discharge rate affects delivered energy.
Questions
- What form of energy does a battery store?
- What is battery capacity?
- What is round-trip efficiency?
- Why does energy out fall short of energy in?
- What does a high C-rate mean?
Answer key (instructors)
- 1. Chemical energy, converted to and from electrical energy.
- 2. The charge it can deliver, usually in amp-hours (Ah) or energy in watt-hours (Wh).
- 3. The fraction of energy recovered on discharge compared with energy used to charge (typically ~85–95% for lithium-ion).
- 4. Internal resistance and chemical inefficiencies dissipate some energy as heat.
- 5. Fast charging or discharging relative to capacity, which usually lowers efficiency and can heat the cell.
A battery stores chemical energy and converts it to electricity on demand. Its capacity (Ah/Wh) sets how much it holds; round-trip efficiency (~85–95% for Li-ion) reflects losses to internal resistance, which grow at high charge/discharge rates.