Product Engineering Processes Battery Primer

Transcription

1 Product Engineering Processes Battery Primer A short battery primer Handbook of batteries, Linden and Reddy

2 Types Primary (dry cell): non rechargeable low power applications infrequent use Secondary: rechargeable high discharge rates frequent use

3 Selection considerations Physical characteristics: size, shape weight Voltage: nominal, maximum, minimum, discharge profile Load current: rate, constant power, constant resistance, pulsed Duty cycle: continuous, intermittent, cyclic Charge/discharge cycle: cycling (float), deep cycle, efficiency of charging Temperature range: maximum, minimum and nominal Service life: required operation time Safety: failure rates, leakage, off-gassing, toxicity, disposal Environment: vibration, acceleration, orientation Maintenance: regular upkeep, replacement Cost: initial, life-cycle cost

4 Cell voltage Cell voltage Voltage (V) Alkaline (p) Lead-acid (s) Nickel-Cadmium (s) Nickel-metal hydride (s) Battery type Lithium-ion (s)

5 Specific energy Specific energy Specific energy (Wh/kg) Alkaline (p) Lead-acid (s) Nickel-Cadmium (s) Nickel-metal hydride (s) Battery type Lithium-ion (s)

6 Energy density Energy density Energy density (Wh/l) Alkaline (p) Lead-acid (s) Nickel-Cadmium (s) Nickel-metal hydride (s) Battery type Lithium-ion (s)

7 Self discharge Shelf life 60 Shelf life Celcius) Alkaline (p) Lead-acid (s) Nickel-Cadmium (s) Nickel-metal hydride (s) Battery type Lithium-ion (s)

8 Estimated cycle life Typical cycle life 1200 Typical cycle life (discharge/charge cycles) Alkaline (p) Lead-acid (s) Nickel-Cadmium (s) Nickel-metal hydride (s) Battery type Lithium-ion (s)

9 Temperature range Operating temperature Temperature (Celcius) Alkaline (p) Lead-acid (s) Nickel-Cadmium (s) Nickel-metal hydride (s) Lithium-ion (s) Battery type

10 Relative cost Cost Relative cost/wh Alkaline (p) Lead-acid (s) Nickel-Cadmium (s) Nickel-metal hydride (s) Battery type Lithium-ion (s)

11 Voltage and state-of-charge

12 Temperature and energy density

13 Temperature and shelf life

14 Power and discharge rate 1000 Watts/litre Nickel-metal hydride (s) Nickel-Cadmium (s) Hours to discharge Alkaline (p) Lithium ion (s)

15 Secondary battery comparison Lead-acid SLI (starting, lighting, ignition) Lead-acid traction Lead-acid stationary Lead-acid portable Nickel-Cadmium (sealed) Nickel-metal hydride Lithium ion advantages disadvantages Cycle life Life (years) low cost, high availability, low cycle life, shallow high current, low discharge cycles, low temperature, good float energy density, poor service, maintenance free charge retention, lowest cost of deep cycle systems designed specifically for float charging cycles maintenance free, long flat service life, low and high temperature, operates in any position rugged, excellent storage, high current, low temperature, operates in any position rugged, high energy density, high current, operates in any position, good cycle life rugged, high energy density, high specific energy, operates in any position, good cycle life, low self discharge hydrogen evolution low energy density, less rugged, hydrogen evolution hydrogen evolution 25 Cannot be stored discharged, lower cycle life, difficult for small batteries high cost, memory effect, poor for float service high cost (between Nickel-Cadmium and Lithium ion) lower current, very high cost

16 Cycle life and discharge depth (lead-acid)

17 Secondary battery charging charge method current rate C(A) charging energy efficiency Lead-acid constant current, constant voltage % Nickel-Cadmium (sealed) constant current % Nickel-metal hydride constant current, constant voltage % Lithium ion constant current, constant voltage %

18 Constant voltage charging (lead-acid)

19 Constant current charging (lead-acid)