As a new drone enthusiast, you must be curious about how to choose a drone battery? What are the differences between different types of batteries? What should you pay attention to when using it?
This article will introduce the types of batteries and understand the battery parameters.
Principle
How batteries work
Batteries are composed of positive electrode materials, negative electrode materials, separators and electrolytes.
When the battery is discharged, electrons move from the negative electrode to the positive electrode to generate electric current. In this process, the flow of electrons generates electrical energy.
Categories
What are the differences between different types of batteries?
The battery is composed of positive electrode material, negative electrode material, separator and electrolyte.
Wet cell battery
Lead-acid batteries are common wet batteries. The positive electrode material is lead dioxide, the negative electrode material is metallic lead, and the electrolyte is sulfuric acid solution.
Commonly used in automobile starting batteries, communications, automatic control, and backup power batteries for emergency equipment.
The advantages are low cost, durability and reliability, but the disadvantages are heavy weight, low energy density and the need for regular maintenance.
Dry Cell
Dry cells are the batteries we use most often, including disposable batteries and rechargeable batteries.
Disposable batteries, such as alkaline batteries and carbon batteries, cannot be recharged after use and are widely used in daily electronic devices;
Common rechargeable batteries include lithium iron phosphate batteries, polymer lithium batteries, lithium-ion batteries, and nickel-cadmium batteries.
Lithium iron phosphate battery (LiFePO4): It has stable chemical properties, high safety, long cycle life, but low energy density.
Commonly used in power tools, electric vehicles and energy storage systems.
Polymer lithium battery (Li-po): High energy density, but requires strict safety management to prevent overcharging and discharging.
Commonly used in drones, model aircraft and other high-power demand equipment.
Lithium ion battery (Li-ion): Energy density is lower than Li-po battery, but the number of cycles is more and the safety is better.
Commonly used in electronic products such as smartphones and laptops.
Nickel cadmium battery (NiCd): Early mobile phone batteries, simple maintenance, but gradually eliminated due to memory effect and environmental issues.
Commonly used in professional tools and emergency lights and other equipment.
What is energy density?
Energy density refers to the energy stored per unit volume or mass, and the unit is usually MJ/L or MJ/kg. Under the same volume, the higher the energy density, the more energy can be generated.
For example, to heat 1 liter of water from 20°C to 100°C, about 0.3135 MJ of energy is required. So 1 MJ of energy can boil about 6 bottles of 500 ml of water.
The energy density of different substances is listed below
(unit volume: MJ/L)
Gasoline: 32
Diesel: 35.8 Aviation fuel: 34
Coal: 22-24
Lithium iron phosphate battery: 0.792-1.26
Lithium ion battery: 0.9-1.62
Polymer lithium battery: 1.08-1.8
Combined with the above battery characteristics, unmanned vehicles generally choose polymer lithium batteries (Li-po) and lithium iron phosphate batteries (LiFePO4).
Since unmanned aircraft are sensitive to weight, polymer lithium batteries with high energy density are usually used; unmanned vehicles are not very sensitive to weight and can use lithium iron phosphate batteries.
Basic parameters of the battery
The important parameters of batteries include charge and discharge rate, battery capacity and voltage.
The charge rate and discharge rate of a battery indicate the rate at which the battery is charged or discharged.
The charge rate is the maximum charge current of the battery. Similarly, the discharge rate indicates the maximum discharge current.
For example: When the battery capacity is 5300mah,
The charging rate of 2C means that the maximum charging current of the battery is 10.6 A.
* [5300 mah (5.3 Ah) * 2 = 10.6 A]
The discharge rate of 10C means that the maximum discharge current of the battery is 53 A.
* [5300 mah (5.3 Ah) * 10 = 53 A]
Battery charge calculation
Batteries with high capacity (mAh or Ah) do not necessarily contain more energy. Based on the basic parameters of the battery, we can derive the power of different batteries.
Battery energy calculation formula is:
Energy (Wh) = Capacity (Ah) × Voltage (V)
For example:
Battery A: capacity 2000 mAh, voltage 4.2 V, then the battery energy = 2 Ah × 4.2 V = 8.4 Wh
Battery B: capacity 2000 mAh, voltage 12.6 V, then the battery energy = 2 Ah × 12.6 V = 25.2 Wh
Battery usage environment and precautions
Operating ambient temperature:
High temperature (over 65 degrees) will cause the electrolyte to decompose, produce gas, increase internal pressure, shorten life and even cause explosion. High temperature will also accelerate the side reaction between the electrolyte and the positive and negative electrode materials, increase internal resistance and reduce performance.
Low temperature will increase electrolyte viscosity, reduce conductivity, affect discharge capacity and capacity, and reduce charging efficiency.
In daily life, I also encounter such situations, such as the battery of mobile phones in winter is not as long as in summer, or the performance of new energy vehicles in the north is reduced due to low temperatures in winter.
Precautions:
The battery must be charged at room temperature and in a dry environment using professional charging equipment.
The full voltage of lithium polymer battery (Li-po) and lithium ion battery (Li-ion) is 4.2V. The full voltage of lithium iron phosphate battery (LiFePO4) is 3.6V. (See the battery manufacturer's manual for details)
The following are the number of charge and discharge cycles of each battery under normal conditions:
Polymer lithium battery (Li-po): 300 to 500 times
Lithium ion battery (Li-ion): 500 times
Lithium iron phosphate battery (LiFePO4): 5000 times
Note when storing the battery: If the battery is not used for a long time, the lithium battery voltage needs to be charged to 3.8-3.85V, and the lithium iron phosphate battery (LiFePO4) needs to be charged to 3.2-3.3V.
In general, when choosing a drone battery, you should calculate the required battery capacity based on the specific needs of the drone (such as load, flight time, etc.), and choose the appropriate battery type and configuration. At the same time, pay attention to the battery's weight, safety, and performance to achieve the best flight effect.