ThePowerofInformationTechnology

1、1The Power of Information TechnologyBattery used in Portable Device2How important?lTell you a StoryWhat a fancy watch!3Wonderful!Only $100!4Critical Preference lEnergy Density( Watt hours per kilogram (Wh/kg). )lWeightlself discharge for spare idle lRecharge ratelCycle Life (to 80% of initial capaci

2、ty) lMemory EffectlSafety and Environmental hazardlCost5Technology Using or will uselNickel Cadmium (NiCd) lNickel-Metal Hydride (NiMH) lLithium Ion (Li-ion).lLithium Ion Polymer (Li-ion polymer).lReusable Alkaline 6Nickel Cadium(NiCd)lmature and well understood lAlkaline nickel battery technology o

3、riginated in 1899 lWaldmar Jungner invented la strong and silent worker , the only battery type that performs best under rigorous working conditions. lMain applications are two-way radios, biomedical equipment, professional video cameras and power tools 7Nickel Cadium(NiCd)lTysonic AA NiCd Battery8A

4、dvantage (NiCd)lFast and simple charge even after prolonged storage.lHigh number of charge/discharge cycles if properly maintained, the NiCd provides over 1000 charge/discharge cycles.lGood load performance the NiCd allows recharging at low temperatures.lLong shelf life in any state-of-charge.lSimpl

5、e storage and transportation most airfreight companies accept the NiCd without special conditions.lGood low temperature performance.lForgiving if abused the NiCd is one of the most rugged rechargeable batteries.lEconomically priced the NiCd is the lowest cost battery in terms of cost per cycle. lAva

6、ilable in a wide range of sizes and performance options most NiCd cells are cylindrical.9LimitationlRelatively low energy density compared with newer systems.lMemory effect the NiCd must periodically be exercised to prevent memory.lEnvironmentally unfriendly the NiCd contains toxic metals. Some coun

7、tries are limiting the use of the NiCd battery.lHas relatively high self-discharge needs recharging after storage.10Nickel-Metal Hydride (NiMH) lNiMH system started in the 1970slHigher energy density than NiCdlAt the expense of reduced cycle life (1/5-1/3 of NiCd)lNo toxic metals lSimilar cost of Ni

8、Cdlmainly used for satellite , applications include mobile phones and laptop computers. 11Nickel-Metal Hydride (NiMH)lFor Nokia 100Category: Ni-mhCapacity: 1200 mahVoltage : 4.8 VStand by: 52-120 h 12Advantagel30 40 percent higher capacity over a standard NiCd. The NiMH has potential for yet higher

9、energy densities.lLess prone to memory than the NiCd. Periodic exercise cycles are required less often.lSimple storage and transportation transportation conditions are not subject to regulatory control.lEnvironmentally friendly contains only mild toxins; profitable for recycling.13LimitationlLimited

10、 service life if repeatedly deep cycled, especially at high load currents, the performance starts to deteriorate after 200 to 300 cycles. Shallow rather than deep discharge cycles are preferred.lLimited discharge current although a NiMH battery is capable of delivering high discharge currents, repea

11、ted discharges with high load currents reduces the batterys cycle life. Best results are achieved with load currents of 0.2C to 0.5C (one-fifth to one-half of the rated capacity).lMore complex charge algorithm needed the NiMH generates more heat during charge and requires a longer charge time than t

12、he NiCd. The trickle charge is critical and must be controlled carefully.lHigh self-discharge the NiMH has about 50 percent higher self-discharge compared to the NiCd. New chemical additives improve the self-discharge but at the expense of lower energy density.lPerformance degrades if stored at elev

13、ated temperatures the NiMH should be stored in a cool place and at a state-of-charge of about 40 percent.lHigh maintenance battery requires regular full discharge to prevent crystalline formation.lAbout 20 percent more expensive than NiCd NiMH batteries designed for high current draw are more expens

14、ive than the regular version.14Lithium Ion (Li-ion) lPioneer work with the lithium battery began in 1912 under G.N. Lewis learly 1970s that the first non-rechargeable lithium batteries became commercially available. lfastest growing battery system lLi-ion is used where high-energy density and light

15、weight is of prime importance lmore expensive than other systems and must follow strict guidelines to assure safety. lApplications include notebook computers and cellular phones. 15lFor Nokia 3310/3390 Category: Li-ionCapacity: 950 mahVoltage : 3.6 VStand by: 72-120 h16AdvantagelHigh energy density

16、potential for yet higher capacities.lRelatively low self-discharge self-discharge is less than half that of NiCd and NiMH.lLow Maintenance no periodic discharge is needed; no memory.17LimitationlRequires protection circuit protection circuit limits voltage and current. Battery is safe if not provoke

17、d.lSubject to aging, even if not in use storing the battery in a cool place and at 40 percent state-of-charge reduces the aging effect.lModerate discharge current.lSubject to transportation regulations shipment of larger quantities of Li-ion batteries may be subject to regulatory control. This restr

18、iction does not apply to personal carry-on batteries.lExpensive to manufacture about 40 percent higher in cost than NiCd. Better manufacturing techniques and replacement of rare metals with lower cost alternatives will likely reduce the price.lNot fully mature changes in metal and chemical combinati

19、ons affect battery test results, especially with some quick test methods.18The Lithium Polymer Battery ldifferentiates itself from other battery systems in the type of electrolyte used lThe polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte lno danger of

20、flammability ,suffers from poor conductivity lA dry solid Li-polymer version is expected to be commercially available by 2005. 19The Lithium Polymer Battery (Cont.)lsome Li-polymers are used as standby batteries in hot climates lunique in that it uses a solid electrolyte, replacing the porous separa

21、tor. The gelled electrolyte is simply added to enhance ion conductivity. lpostponement, as some critics argue, is due to cashing in on the Li-ion battery lcompelled mobile phone manufacturers to use this promising technology for their new generation handsets. 20The Lithium Polymer Battery (Cont.)lAn

22、imal Cam From Ultralife21AdvantagelVery low profile batteries that resemble the pro a credit card are feasible.lFlexible form factor manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.lLight weight gelled rather than liquid electr

23、olytes enable simplified packaging, in some cases eliminating the metal shell.lImproved safety more resistant to overcharge; less chance for electrolyte leakagelLeakage proof (no free electrolyte) lHigh energy density lLong cycle life lEnvironmentally friendly22LimitationlLower energy density and de

24、creased cycle count compared to Li-ion potential for improvements exist.lExpensive to manufacture once mass-produced, the Li-ion polymer has the potential for lower cost. Reduced control circuit offsets higher manufacturing costs.23Reusable Alkaline Batteries lreplaces disposable household batteries;l suitable for low-power applications. lIts limited cycle life is compensated by low self-discharge, lideal for portable entertainment devices and flashlights. 24Reusable Alkaline Batteries(Cont.)lRenewal Reusable A