6.9: Secondary batteries
- Page ID
- 21173
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Secondary (rechargeable) batteries can be recharged by applying a reverse current, as the electrochemical reaction is reversible. The original active materials at the two electrodes can be reconstituted chemically and structurally by the application of an electrical potential between the electrodes to “inject” energy. These batteries can be discharged and recharged many times.
Applications:
These fall into two categories:
(a) The battery is used as an energy storage device. It is constantly connected to an energy source and charged by it. It can then release the stored energy whenever needed, e.g. in
- Car battery used to start engine
- Aircraft systems
- Standby power resources
- Emergency no-fail systems
(b) The battery is used as a primary battery would be but is then recharged instead of being disposed of, e.g. in
- Electric vehicles
- Mobile phones
- Cameras
- Power tools
- Toys
- Portable computers
Advantages:
- High power density
- High discharge rate
- Good low temperature performance
Disadvantages:
- Lower Energy density
- Poorer charge retention
- Safety issues
- Lack of standards
- High initial costs
The table below demonstrates the properties of various rechargeable batteries:
| System | Nominal Cell Voltage (V) | Capacity (Wh/kg) | Advantages | Disadvantages | Applications |
|---|---|---|---|---|---|
|
2.00
|
35
|
Low cost; good high and low-temperature operation
|
Low cycle life; low energy density; poor charge retention
|
Cars; lawn mowers; aircraft
|
|
|
Ni/Cd
|
1.20
|
30
|
Good physical durability; good charge retention; good cycle life
|
High cost; memory effect
|
Aircraft; emergency power applications
|
|
Ni/Fe
|
1.20
|
60
|
Good physical durability; long cycling and standing life
|
Low power and energy density; high self discharge; high cost
|
Stationary applications; fork lift trucks
|
|
Ni/Zn
|
1.60
|
27
|
High energy density; low cost; good low-temperature performance
|
Poor cycle life
|
Electric scooters/bikes; military vehicles
|
|
Zn/AgO
|
1.50
|
90
|
Highest energy density; low self discharge; high discharge rate
|
High cost; low cycle life; low performance at low temperatures
|
Military equipment eg torpedo propulsion, submarines
|
|
Cd/AgO
|
1.20
|
55
|
High energy density; low self discharge; Good cycle life
|
High cost; low performance at low temperatures
|
Portable power tools; satellites
|
|
Ni/H2
|
1.40
|
55
|
High energy density; good cycle life; can tolerate over charge
|
High initial cost; self discharge proportional to H2 pressure
|
Aerospace
|
|
Ag/H2
|
1.40
|
80
|
High energy density; good cycle life
|
High cost - limited to military and aerospace applications
|
Aerospace
|
|
up to 4.2
|
135
|
High specific energy; good shelf life; moldable; non-volatile
|
High cost; expensive control methods needed for charge/discharge
|
Mobile phones
|