Baterije in njihova uporaba

Primerjalna tabele med različnimi na Litiju bazečimi baterijami

C-LiFePO4 LiCoO2 LiMn2O4 Li(NiCo)O2
Varnost in obremenitev okolja Odlično, najboljše med vsemi trenutnimi Ni stabilna in zelo nevarna Sprejemljiva Ni stabilna in zelo nevarna
Življenska doba Odlična najboljša med navedenimi skupinami Sprejemljiva Nesprejemljiva Sprejemljiva
Razmerje med težo in shranjeno kapaciteto Sprejemljivo Zadovoljivo Sprejemljivo Najboljše
Dolgoročni stroški Najboljše in najbolj ekonomično Visoki Sprejemljivi Visoki
Delovna temperatura Odlična
45C-70C
Razpada pri -20C in naprej Razpada izredno hitro pri temp. večjih od 50C Razpada izredno hitro pri temp. pod -20C
ZAZNAMKI 1. Glede na to da so kislinske baterije najcenejše in relativno varne so pa izredno strupene in okolju škodljive življenska doba je kratka in so zelo težke jih nismo uvrstili v primerjavo.

2. Nikel metal Hidridne(NiMH) baterije imajo karakteristike zelo nizke moči glede na težo, razpadajo hitro pri visokih temperaturah, imajo slab spominski efekt in niso primerne za visoke obremenitve tudi niso v primerjalni tabeli.
Razstavljena baterija

3. Ogljikovo prevlečen Lithium Iron Phosphate baterije (LiFePO4) znane tudi kot LFP, so se izkazale kot najbolj okoljsko varne. So najvarnejše in najbolj primerne za visoko porabo. So tudi najboljše hranilke energije!

Graf prikazuje padanje napetosti glede na število polnilnih ciklov LiFePO4 baterije

LiFePo4 (LFP na kratko) so odkrili 1996 kot katodni del na litiju bazeče baterije. Ker je taka kombinacija za izdelavo poceni poleg tega pa je takšna kemijska struktura nestrupena, je temperaturno stabilna, ima dobre elektrokemične sposobnosti ter visoko specifično kapacitivnost (170mA-h/g), po domače shrani v gram 170miliamperskih ur.

Karakteristike so zelo podobne družini Litijevih baterij vendar je par le teh drugačnih. Ima vrhunsko temperaturno in kemično stabilnost kar pomeni večjo varnost. Ravno tako se ponaša z izredno dolgo življensko dobo ter preko 1500 polnilnih ciklov

Nekaj specifikacij:
Perioda uporabe: > 10 let
Napetost posamezne celice: 2.8V
Delovna napetost celice = 3.0V – 3.3V
Maksimalna polnilna napetost = 3.6V
DOD (Depth of Discharge) Globina praznitve: do 80% originalne kapacitet: Pri tem parametru je število polnilnih ciklov med 2000 in 7000.

Li-Ion tehnologija

Li-Ion baterije so v zelo kratkem času postale zelo popularna tehnologija. Proizvedejo enako količino energije kot NiMH vendar so za 35% lažje, kar pa pri električnih vozilih izdatno pripomore k sami teži vozila. Drugi razlog popularnosti je da Li-Ion baterije niso strupene in so okolju prijazne ker ne vsebujejo toksičnih elementov kot so Kadmij in podobno. Tretji razlog je spominski efekt katerega te baterije nimajo. Ta efekt pri določenih tipih baterij kot recimo NiMH izdatno poslabša izkoristek in življensko dobo baterij. Li-Ion se stalno izboljšuje z novimi materiali postajajo baterije temelječe na Litiju mesečno boljše.

Z pravim načinom uporabe baterije lahko povečamo njeno uporabnost.

Nove baterije pravilo pridejo v izpraznjenem stanju in jih je pred uporabo potrebno napolniti. Polno kapaciteto dosežejo šele pri 3-eh polnenjih.

Kontakte baterij po potrebi očistite umazanije ali druge nesnage, ki se lahko tam nabira. Spoji in kontakti naj bodo čimboljši in čimmanj korozivni in zrahljani.

Baterijo je traba včasih “pretegniti”. Ne pustite jo brez dela predolgo. Priporočamo, da jo vsakih 14 dni ali 3 tedne uporabljate.

Li-Ion baterije ne marajo, da jih praznimo do skrajnih meja. Raje imajo, da se jih prazni delno. Ker nimajo spominskega efekta je to za to tehnologijo boljše.

V kolikor baterijo ne boste uporabljali dalj časa, jo je priporočljivo shraniti v suhem, čistem in na normalni temperaturi, proč od virov toplote in proč od kovinskih predmetov. NiCad, NiMH in Li-Ion baterije se sčasoma same od sebe spraznijo. Ne pozabite, da jih je potrebno napolniti pred naslednjo uporabo. Pri tehnologiji Li-Ion je najbolša shramba pri 40% napolnjenosti. Čisto prazne baterije zaradi lastne potrošnje ni priporočljivo hraniti !

Baterije imajo nazivne parametre od njih sta pomembna dva in to sta Napetost(V) ter Amperske ali miliamperske ure(Ah, mAh).

Življenska doba baterije, ki jo je mogoče polniti je med 500 in 800 polnilnih ciklov, torej povprečno 3 do 4 leta. Nove tehnologije, ki prihajajo pa tudi pri pravilni uporabi več.

Pri polnjenju Li-Ion baterij so le te zelo občutljive glede polnilne napetostji po posamezni celici, ki zaradi življenske dobe ne sme presegati 4.2V.

Baterije ravno tako ne izpostavljamo velikim temperaturnim šokom, ker s tem povzročamo efekt povečanja notranje upornosti in s tem slabše izkoristke.

Li-Ion baterija je raje na hladnem “ne mrzlem” kot toplem.

Pri Li-Ion tehnologiji ni priporočljivo praznenje pod 2.5V po posamezni celici ker s tem povzročimo “navidezno smrt” baterije in jo s klasičnim polnilcem ne moremo več oživeti. Nekateri polnilci imajo zato možnost polnilne funkcije, ki poizkuša oživeti baterijo z sunki. Če pa je napetost padla po celici pod 1.5V odsvetujemo ponovno polnenje, zaradi varnosti !

VRLA (Q & A)

Q1, What is the definition of “cycle use” and “standby use”?
“Cycle Use” – direct power source:
It can provide the power supply to power tools, portable electronic products. It can also be used for cycling charging and discharging usage such as electronics motorbike or vacuum cleaner.
“Standby Use” – back up power:
Mainly used for emergency power to avoid future damage that may be caused by a sudden power outage.

Q2, What are the concerns when using Ritar batteries in a parallel or a serial series?
1. Do not mix brands, models and date codes?
2. No separate discharge then charging in a serial configuration.
3. Under parallel usage, pay close attention to the differences in voltage in each circuit.
4. If the difference in voltage in each circuit is too high, do not charge/discharge as parallel.
5. The environment of all circuits must be similar.


Q3, How can you check a battery”s performance?
Different usage applications will use different methods for evaluating a battery”s performance. Using a 20 hour rate or the 10 hour rate, you can use 0.05CA or 0.1CA to discharge the battery until the battery reaches a terminal voltage of 10.25 volts. You can then calculate the amp hours to see if the battery fits the specifications or not. For a 5 minutes rate, such as the HC1221W, you can use a 21 watts/cell discharge till the terminal voltage reaches a terminal voltage of 9.6 volts and then measure the discharge time to see if it meets the final specifications or not.

Q4, How can the conversion be made between “watts (W)” and “amp hours (Ah)”?
W=I x V = 4I (15 minute rate) = 2CV = 2V
(Ex. HC1217W = 17/4 = 4.25Ah)

Q5, When should a deep-cycle battery be used?
Deep-cycle batteries are used when 50% or more of the capacity is used per cycle. The most common use of deep-cycle batteries is in applications that require deep, repetitive drain, like powerful car audio systems, trolling motors, golf carts, electric wheelchairs, or RV house power sources. Public safety and high-performance vehicles are other applications that call for the special characteristics of deep-cycle batteries.

Q6, Does the deep-cycle battery have a “memory”?
No. The performance of deep-cycle batteries will be reduced over time, but deep-cycle batteries do not suffer from “memory effect” such as NiCd batteries do.

Q7, How are batteries rated?
Lead acid batteries are rated based on a capacity given in a defined time. There is not a set industry standard for how to rate a battery.

Q8, How long a battery can last?
The service design life of a battery are vary considerably with how it is used, how it is maintained and charged, temperature, and other factors.

Q9, Do I need to add water to my battery?
No. Sealed lead acid batteries do not require the use of water.

Q10, What determines the life of an VRLA battery?
Sealed lead acid battery life is determined by many factors. These include temperature, depth and rate of discharge, and the number of charges and discharges(called cycles).

Q11, What is the difference between float and cycle applications?
A float application requires the battery to be on constant charge with an occasional discharge. Cycle applications charge and discharge the battery on a regular basis.

Q12, Does overcharging damage batteries?
OVERCHARGING is the most destructive element in battery service. Usually the boater is not aware that this is occurring as he believes his alternator or battery charger is “automatic.” Unfortunately, these automatic circuits are sensitive to voltage surges, heat, direct lightening strikes and indirect lightening electromagnetic influences and could fail or shift their calibration. When they fail, overcharging begins to effect the batteries. During overcharging, excessive current causes the oxides on the plates of the battery to “shed” and precipitate to the bottom of the cell and also heat the battery, thus removing water from the electrolyte. Once removed, this material (which represents capacity) is no longer active in the battery. In addition, the loss of water from the electrolyte may expose portions of the plates and cause the exposed areas to oxidize and become inactive, thus reducing additional capacity. Sealed batteries are not immune from the same internal results when overcharged. In fact, sealed recombination absorption and gel batteries are particularly sensitive to overcharging. Once moisture is removed from the battery, it cannot be replaced. Portions of the battery damaged due to overcharging are irretrievable. However, if detected early, corrective adjustments to the charging device will save the undamaged portion of the battery. Initial signs of overcharging are excessive usage of water in the battery, continuously warm batteries, or higher than normal battery voltages while under the influence of the charger. If overcharging is suspected, correct immediately.

Q13, Does overdischarging damage batteries?
OVERDISCHARGING is a problem which originates from insufficient battery capacity causing the batteries to be overworked. Discharges deeper than 50% (in reality well below 12.0 Volts or 1.200 Specific Gravity) significantly shorten the Cycle Life of a battery without increasing the usable depth of cycle. Infrequent or inadequate complete recharging can also cause overdischarging symptoms called SULFATION. Despite that charging equipment is regulating back properly, overdischarging symptoms are displayed as loss of battery capacity and lower than normal specific gravity. Sulfation occurs when sulfur from the electrolyte combines with the lead on the plates and forms lead-sulfate. Once this condition becomes chronic, marine battery chargers will not remove the hardened sulfate. Sulfation can usually be removed by a proper desulfation or equalization charge with external manual battery chargers. To accomplish this task, the flooded plate batteries must be charged at 6 to 10 amps. at 2.4 to 2.5 volts per cell until all cells are gassing freely and their specific gravity returns to their full charge concentration. Sealed AGM batteries should be brought to 2.35 volts per cell and then discharged to 1.75 volts per cell and their this process must be repeated until the capacity returns to the battery. Gel batteries may not recover. In most cases, the battery may be returned to complete its service life.
CHARGING Alternators and float battery chargers including regulated photo voltaic chargers have automatic controls which taper the charge rate as the batteries come up in charge. It should be noted that a decrease to a few amperes while charging does not mean that the batteries have been fully charged. Battery chargers are of three types. There is the manual type, the trickle type, and the automatic switcher type.

Q14, How can I evaluate the health and charge state of a battery?
Routine battery examinations divulge irregularities in the charging system as well as in the batteries. The principle method is to examine the electrochemistry of the battery through hydrometric electrolyte inspection. As previously discussed, this important examination cannot be accomplished with sealed absorption or gel batteries. Voltage readings alone require experience to interpret. Hydrometric readings will uncover early warnings of overcharging or overdischarging before batteries are damaged. The state-of-charge and reliability of a lead acid battery can best be determined by the specific gravity of the electrolyte measured directly with a common bulb-type hydrometer with a glass float. We do not recommend the ball float type hydrometer. Specific gravity is a unit of measurement for determining the sulfuric acid content of the electrolyte. The recommended fully charged specific gravity of marine batteries is 1.255 to 1.265 taken at 80??C More than .025 spread in readings between fully charged cells indicates that the battery may need an equalization charge. If this condition persists, the cell is failing and the battery should be replaced. Since water has a value of 1.000, electrolyte with a specific gravity of 1.260 means it is 1.260 times heavier than pure water while pure concentrated sulfuric acid has a specific gravity of 1.835.

Comparison Table of Secondary Batteries

Rechargeable batteries play an important role in our life and many daily chores would be unthinkable without the ability to recharge an empty battery. Points of interest are specific energy, years of service life, load characteristics, safety, price, self-discharge, environmental issues, maintenance requirements, and disposal.

Lead Acid — One of the oldest rechargeable battery systems; is rugged, forgiving if abused and economical in price; has a low specific energy and limited cycle life. Lead acid is used for wheelchairs, golf cars, personnel carriers, emergency lighting and uninterruptible power supply (UPS).

Nickel-cadmium (NiCd) — Mature and well understood; is used where long service life, high discharge current, extreme temperatures and economical price are of importance. Due to environmental concerns, NiCd is being replaced with other chemistries. Main applications are power tools, two-way radios, aircraft and UPS.

Nickel-metal-hydride (NiMH) — A practical replacement for NiCd; has higher specific energy with fewer toxic metals. NiMH is used for medical instruments, hybrid cars and industrial applications. NiMH is available in AA and AAA cells for consumer use.

Lithium-ion (Li‑ion) — Most promising battery systems; is used for portable consumer products as well as electric powertrains for vehicles; is more expensive than nickel- and lead acid systems and needs protection circuit for safety.

The lithium-ion family is divided into three major battery types, so named by their cathode oxides, which are cobalt, manganese and phosphate. The characteristics of these Li-ion systems are as follows.

Lithium-ion-cobalt or lithium-cobalt (LiCoO2): Has high specific energy with moderate load capabilities and modest service life. Applications include cell phones, laptops, digital cameras and wearable products.

Lithium-ion-manganese or lithium-manganese (LiMn2O4): Is capable of high charge and discharge currents but has low specific energy and modest service life; used for power tools, medical instruments and electric powertrains.

Lithium-ion-phosphate or lithium-phosphate (LiFePO4): Is similar to lithium-manganese; nominal voltage is 3.3V/cell; offers long cycle life, has a good safe record but exhibits higher self-discharge than other Li-ion systems.

There are many other lithium-ion based batteries, some of which are described further on this website. Missing in the list is also the popular lithium-ion-polymer, or Li-polymer. While Li-ion systems get their name from their unique cathode materials, Li-polymer differs by having a distinct architecture. Nor is the rechargeable lithium-metal mentioned. This battery requires further development to control dendrite growth, which can compromise safety. Once solved, Li-metal will become an alternative battery choice with extraordinary high specific energy and good specific power.

Table 1 compares the characteristics of four commonly used rechargeable battery systems showing average performance ratings at time of publication.

Table 1: Characteristics of commonly used rechargeable batteries
The figures are based on average ratings of commercial batteries at time of publication; experimental batteries with above-average ratings are excluded.

1 Internal resistance of a battery pack varies with milliampere-hour (mAh) rating, wiring and number of cells. Protection circuit of lithium-ion adds about 100mW.
2 Based on 18650 cell size. Cell size and design determines internal resistance.
3 Cycle life is based on battery receiving regular maintenance.
4 Cycle life is based on the depth of discharge (DoD). Shallow DoD improves cycle life.
5 Self-discharge is highest immediately after charge. NiCd loses 10% in the first 24 hours, then declines to 10% every 30 days. High temperature increases self-discharge.
6 Internal protection circuits typically consume 3% of the stored energy per month.
7 The traditional voltage is 1.25V; 1.2V is more commonly used.
8 Low internal resistance reduces the voltage drop under load and Li-ion is often rated higher than 3.6V/cell. Cells marked 3.7V and 3.8V are fully compatible with 3.6V.
9 Capable of high current pulses; needs time to recuperate.
10 Do not charge regular Li-ion below freezing. See Charging at High and Low Temperatures.
11 Maintenance may be in the form of equalizing or topping charge to prevent sulfation.
12 Cut-off if less than 2.20V or more than 4.30V for most Li-ion; different voltage settings apply for lithium-iron-phosphate.

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