Pack of 2 units of Duracell 3V 20xx2.5mm CR2025 lithium button cell

Li-Ion or Lithium batteries are one of the most common batteries used today.
We can find this type of battery in mobile phones, wireless headphones, UPS, smartwatches, cars, etc.

Lithium is a very light metal capable of generating ions easily, making it ideal for the manufacture of batteries.

Unlike other types of batteries, they are a bit more expensive, but in return, they are much smaller and lighter, capable of doubling the duration of a Ni-Cd battery.

Thanks to their composition, they can be manufactured in different shapes, adapting to the device where they are to be located, and their low memory effect makes them ideal for any type of device.

Summarizing their positive points:

• Easy to find
• Many different sizes and shapes
• Small size
• Lightweight
• Capable of accumulating more charge
• Less memory effect
• Long lasting
• Low self-discharge rate.

These batteries also have their negative points, namely:

• Lifespan of about 3 years.
• Limited number of charges, between 300 and 1000.
• They are more expensive.
• They can overheat to the point of exploding.
• Poorer performance in cold conditions.
• Highly variable voltage.

Within lithium batteries, we can find 3 types:

• Lithium-ion polymer batteries.
• Lithium iron phosphate (LiFePO4).
• Olivine-type lithium iron phosphate batteries.

BATTERY TYPE	NI-CD	NI-MH	LI-ION	LI-PO
Charging time	10 to 14 hours	2 to 4 hours	2 to 4 hours	1 to 1.5 hours
Discharge time/month	30.00 %	20.00 %	6.00 %	6.00 %
Number of recharges	approx. 500	approx. 1000	approx. 4000	approx. 5000
Discharge	Necessary	Recommended	Failure at 2.5 v	Failure at 2.5 v
Overcharge	Supported	NOT recommended	Supported	Supported
Power/kilo	50 Wh/kg	70 Wh/Kg	110-160 Wh/Kg	100-130 Wh-Kg
Memory effect	Very High	Low	None	None
Ah (Ampere hours)	0.5 – 1Ah	0.5 – 10 Ah	-	-
Voltage per cell	1.2 V	1.2 V	3.7 V	3.7 V

This type of batteries are very common in devices such as watches, computers, calculators, remote controls etc .. thanks to its small size is ideal for small devices.

Its very peculiar shape is of cylindrical and flat type, with two discs, one upper connected to the positive pole (4) and one in the lower part connected to the negative pole (5).

According to the model we will find them with voltages of vary between 1.2and 3 V (3).

This type of stack can be divided into two large groups:

• Primary batteries: They are depleted as they are used.
• Secondary batteries: They can be recharged by passing an electric current through them in the opposite direction.

Since there are numerous types of button-type batteries in the market, it is advisable that before buying it, the model of the battery is verified, all battery models inu upper part indicate the model, normally this reference begins with two or three letters (1) followed by a numbering (2).

It is mandatory to dispose of exhausted batteries at a recycling point, as these types of batteries are highly polluting due to their composition.

1. Metal cathode (+).
2. Zinc anode (-).
3. Zinc (Electrolytic).
4. Isolation.
5. Separator (porous).
6. PaAg2o sta.

Inside the button cells you will find 4 types according to their chemical composition.

• Alkaline: They are the most common, are composed of zinc as anode and manganese dioxide (MnO2) as cathode, its voltage is 1.5 volts, the most common: LR54, LR44, LR43, LR9.
• Lithium: Its chemical composition can be Manganese-Lithium Dioxide, LiMnO2, Polycarbonate-Lithium Monofluoride or Thionyl Chloride-LiUncle Tadiran. The most common, CR1025, CR1216, CR1220, BR1225, CR1612, CR1616, CR1620, CR1632, CR2016, CR2025, BR/CR2032, BR2325, BR/CR2330, CR2354, CR2450, CR2477, CR3032. Their voltages vary between 3 and 3.6 volts.
• Silver oxide: Very good at low temperatures, its voltage is 1.55 volts. The most common, SR41, SR42, SR43, SR44, SR45, SR48, SR54, SR55, SR57, SR58, SR59, SR60, SR62, SR63, SR64, SR65, SR66, SR67, SR68, SR69.
• Zinc air cells: Normally used in hearing aids, their voltage is 1.4 volts., The most common: PR70, PR48, PR41 or PR44.

Within the wide range of batteries on the market we can differentiate two large groups, disposable batteries and rechargeable batteries.
Disposable batteries are those that only allow a single use and when they are exhausted they can not be recharged. These batteries can store their energy for years.

Rechargeable batteries are those that can be recharged once exhausted. This type is losing charge when they are storedaccording to voltage. The most common we can find them of 1.2V and 3.7V

As a last point you have to take into account that lithium batteries, Lipo, Life etc. Due to its composition, specific loaders should be used.