What Battery Chemistry Will Be the Best for My Device?

The battery chemistry that will be best for your device depends on the device and the application. Many devices will simply not allow you swap chemistry types. The big exception to this rule is power tools where you can use NICD, NIMH, or Li-ion battery chemistry types.

Let’s take a more detailed look at: NiCd, NiMH, Li-ion, Li-Po, and Reusable Alkaline batteries.

By the numbers we get the following:

 

NiCd

NiMH

Lead
  Acid

Li-ion

Li-ion
  polymer

Reusable

  Alkaline

Gravimetric Energy Density(Wh/kg)

45-80

60-120

30-50

110-160

100-130

80
  (initial)

Internal Resistance 
(includes peripheral circuits) in mΩ

100 to 2001

  6V pack

200 to 3001

  6V pack

<1001 

12V pack

150 to 2501

  7.2V pack

200 to 3001

  7.2V pack

200 to 20001

  6V pack

Cycle   Life (to 80% of initial capacity)

15002

300 to 5002,3

200 to 3002

500 to 10003

300 to 500

503 (to 50%)

Fast Charge Time

1h

2-4h

8-16h

2-4h

2-4h

2-3h

Overcharge Tolerance

moderate

low

high

very
  low

low

moderate

Self-discharge / Month (room temperature)

20%4

30%4

5%

10%5

~10%5

0.3%

Cell Voltage(nominal)

1.25V6

1.25V6

2V

3.6V

3.6V

1.5V

Load Current

  – peak

  – best result

  20C

  1C

  5C

  0.5C or lower

  5C7

  0.2C

  >2C

  1C or lower

  >2C

  1C or lower

  0.5C

  0.2C or lower

Operating Temperature(discharge only)

-40 to 60°C

-20 to 60°C

-20 to 60°C

-20 to 60°C

0 to 60°C

0 to 65°C

Maintenance Requirement

30 to 60 days

60 to 90 days

3 to 6 mos9

not req.

not req.

not req.

Typical Battery Cost

  (US$, reference only)

$50

  (7.2V)

$60

  (7.2V)

$25

  (6V)

$100

  (7.2V)

$100

  (7.2V)

$5

  (9V)

Cost per Cycle(US$)11

$0.04

$0.12

$0.10

$0.14

$0.29

$0.10-0.50

Commercial use since

1950

1990

1970

1991

1999

1992

 

 

1: Characteristics of commonly used rechargeable batteries

  1. Internal resistance of a battery pack varies with cell rating, type of protection
    circuit and number of cells. Protection circuit of Li‑ion and
    Li-polymer adds about 100mΩ.
  2. Cycle life is based on battery receiving regular maintenance. Failing to apply
    periodic full discharge cycles may reduce the cycle life by a factor of three.
  3. Cycle life is based on the depth of discharge. Shallow discharges provide more cycles
    than deep discharges.
  4. The discharge is highest immediately after charge, then tapers off. The NiCd
    capacity decreases 10% in the first 24h, then declines to about 10% every 30
    days thereafter. Self-discharge increases with higher temperature.
  5. Internal protection circuits typically consume 3% of the stored energy per month.
  6. 1.25V is the open cell voltage. 1.2V is the commonly used value. There is no difference
    between the cells; it is simply a method of rating.
  7. Capable of high current pulses.
  8. Applies to discharge only; charge temperature range is more confined.
  9. Maintenance may be in the form of ‘equalizing’ or ‘topping’ charge.
  10. Cost of battery for commercially available portable devices.
  11. Derived from the battery price divided by cycle life. Does not include the cost of
    electricity and chargers.

Data taken from Battery University all rights reserved