What are the common batteries for electric bicycles?
The common batteries for electric bicycles on the market now include lithium batteries and lead-acid batteries. So how are they different?
One: lithium battery
Lithium batteries can be divided into cylindrical batteries, square batteries, and soft-pack batteries according to the subdivision of the batteries.
1: Cylindrical battery
Common cylindrical battery cell specifications are: 18650, 32650. The most common is 18650 batteries. 18650 batteries are divided into energy storage batteries and power batteries. Energy storage batteries are suitable for electric bicycles that do not require high discharge current, such as small electric bicycles that require a driving speed of 30KM/H. The power cell has a large discharge current, such as 3C discharge, 5C discharge and 10C discharge; it is often used for electric bicycles and electric motorcycles that require driving speed.
Cylindrical batteries have the advantages of mature technology, wide range of applications, variable combinations, and low prices. Cylindrical batteries are divided into lithium ion batteries and lithium iron phosphate batteries from the positive electrode material. The lithium ion batteries have a rated voltage of 3.6V or 3.7V, a full charge of 4.2V, and a discharge limit of 2.75 or 3.0V. Common materials for lithium-ion batteries include lithium manganese oxide, lithium cobalt oxide, and ternary lithium. The lithium iron phosphate battery has a rated voltage of 3.2V and a full charge of 3.6V; the discharge voltage is limited to 2.5V or 2.0V. Cylindrical batteries are currently the main force of electric bicycle batteries.
2: Square battery
Commonly used square battery cells for electric bicycles are 3.2V lithium iron phosphate square batteries and 3.7V lithium ion square batteries. Different from cylindrical batteries, the capacity of square batteries is generally very large, such as 50Ah, 60Ah, 80Ah, etc. The size is generally large and the price is also expensive. A battery is calculated according to how much 1Ah is. Compared with cylindrical batteries, it is more convenient to form an electric bicycle battery, just connect in series. It is used more on electric motorcycles, and the batteries used in low-speed vehicles are generally square batteries.
3: Soft pack battery
The difference between a soft pack battery and a cylindrical battery is not that big, but the shape and process are different. The voltage is generally 3.7V, and the small capacity is only a few hundred mAh and the large capacity is more than 10,000 mAh. Soft pack batteries are also known as lithium polymer batteries. They are a little safer than cylindrical batteries. They will not explode like cylindrical batteries, but will catch fire or deflagration. Only some electric bicycles use soft pack batteries as batteries.
Two: Lead-acid battery
Lead-acid batteries used in electric bicycles are mostly maintenance-free. Lead-acid batteries are batteries whose electrodes are mainly made of lead and its oxides and whose electrolyte is a sulfuric acid solution. In the discharge state of a lead-acid battery, the main component of the positive electrode is lead dioxide and the main component of the negative electrode is lead; in the charged state, the main component of the positive and negative electrodes are lead sulfate. The nominal voltage of a single-cell lead-acid battery is 2.0V, which can be discharged to 1.5V and can be charged to 2.4V; 6 single-cell lead-acid batteries are often connected in series to form a lead-acid battery with a nominal 12V. Common capacities are 12Ah, 20Ah. It is similar to a prismatic battery but heavier than a prismatic battery. When using, only a single battery is connected in series to form 48V and 60V. The lead-acid capacity is generally not large. The number of cycles is about 300-500, and it is not resistant to low temperatures. In the northern winter, the battery usage time may be directly discounted by 50%.
The above is the introduction of two common batteries for electric bicycles. For the time being, lead-acid batteries still account for the majority of batteries. However, due to the emergence of the new national standard, which limits the weight and volume of electric bicycles, it is believed that lithium batteries will gradually replace lead-acid batteries.