6.4: Primary batteries
- Page ID
- 7817
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Primary batteries are not easily rechargeable, and consequently are discharged then disposed of. Many of these are “dry cells” – cells in which the electrolyte is not a liquid but a paste or similar. The cell electrochemical reactions are not easily reversible and cell is operated until the active components in the electrodes are exhausted. Generally primary batteries have a higher capacity and initial voltage than rechargeable batteries.
Applications:
- Portable devices
- Lighting
- Toys
- Memory back-up
- Watches/clocks
- Hearing aids
- Radios
- Medical implants
- Defence related systems such as missiles
Advantages:
- Inexpensive
- Convenient
- Lightweight
- Good shelf life
- High Energy density at low/moderate discharges
Disadvantages:
- Can only be used once
- Leads to large amount of waste batteries to be recycled
- Batteries put into landfill sites have severe environmental impact
- Life cycle energy efficiency < 2 %
The table below demonstrates the properties of various primary batteries:
| System | Nominal Cell Voltage (V) | Capacity (Wh/kg) | Advantages | Disadvantages | Applications |
|---|---|---|---|---|---|
|
1.50
|
65
|
Lowest cost; variety of shapes and sizes
|
Low energy density; poor low-temperature performance
|
Torches; radios; electronic toys and games
|
|
|
Mg/MnO2
|
1.60
|
105
|
Higher capacity than C/Zn; good shelf life
|
High gassing on discharge; delayed voltage
|
Military and aircraft receiver-transmitters
|
|
1.50
|
95
|
Higher capacity than C/Zn; good low-temperature performance
|
Moderate cost
|
Personal stereos; calculators; radio; TV
|
|
|
Zn/HgO
|
1.35
|
105
|
High Energy density; flat discharge; stable voltage
|
Expensive; energy density only moderate
|
Hearing aids; pacemakers; photography; military sensors/detectors
|
|
Cd/HgO
|
0.90
|
45
|
Good high and low-temperature performance; good shelf life
|
Expensive; low energy density
|
|
|
1.50
|
130
|
High Energy density, good high rate performance
|
Expensive (but cost effective)
|
Watches; photography; missiles; Larger space applications
|
|
|
Zn/Air
|
1.50
|
290
|
High Energy density; long shelf life
|
Dependent on environment; limited power output
|
Watches; hearing aids; railway signals; electric fences
|
|
Li/SOCl2
|
3.60
|
300
|
High Energy density; long shelf life
|
Only low to moderate rate applications
|
Memory devices; standby electrical power devices
|
|
Li/SO2
|
3.00
|
280
|
High energy density; best low-temperature performance; long shelf life
|
High-cost pressurized system
|
Military and special industrial needs
|
|
Li/MnO2
|
3.00
|
200
|
High energy density; good low-temperature performance; cost effective
|
Small in size, only low-drain applications
|
Electrical medical devices; memory circuits; fusing
|