Lithium battery energy storage is an inevitable trend of the development of the times. The application and development of lithium battery is very rapid. It has the advantages of high energy density, long service life, green and environmental protection.
Lithium battery is a kind of battery with lithium metal or lithium alloy as cathode material and non-aqueous electrolyte solution. Because the chemical properties of lithium metal are very active, the processing, preservation and use of lithium metal have very high requirements for the environment. Lithium battery is widely used in electric vehicle industry, especially the emergence of lithium iron phosphate battery, which promotes the development and application of lithium battery industry.
Price composition of lithium battery
The price of lithium battery is mainly composed of three parts: cell, protective plate and shell. At the same time, due to the power consumption and current of the electrical appliances, the material selection of the connecting piece between the electric cores will affect the cost. Different connectors may also have a great impact on the cost, and different pack processes may also affect the cost.
Factors affecting the price of lithium battery
Selection of cell
The selection of cells with different material systems will affect the price of the whole lithium battery. According to different cathode materials, lithium battery pack will have lithium manganate (3.6V), lithium cobaltate (3.7V / 3.8V), nickel cobalt lithium manganate (commonly known as ternary, 3.6V), lithium iron phosphate (3.2V), lithium titanate (2.3V / 2.4V) and other material systems. The voltage platform, safety factor, cycle times, energy density ratio and working temperature of cells with different material systems are different.
The prices of different brands of batteries will also vary greatly. The total price gradient can be divided into: the price difference of different brands of cells with the same material system will also be very large. Moreover, the quality of each brand of electric core through the survival of the fittest in the market is basically proportional to the price.
Demand and design of lithium battery PCM
PCM design can be divided into: basic protection, communication and BMS.
Basic protection: basic protection includes overcharge, over discharge, over-current and short circuit protection, and over-temperature protection can be added according to product requirements.
Communication: the communication protocol can be divided into I2C, RS485, RS232, CANbus, HDQ, SMBus, etc. there is also a simple power display, which can be indicated by power meter and led.
BMS: battery management system is mainly used to intelligently manage and maintain each battery unit, prevent overcharge and overdischarge of the battery, prolong the service life of the battery and monitor the state of the battery. Its main functions include real-time monitoring of battery physical parameters, battery state estimation, online diagnosis and early warning, charge, discharge and precharge control, balance management and thermal management.
Demand and design of lithium battery shell
Lithium battery shell design can be divided into: PVC heat seal, plastic and metal
PVC heat seal: what kind of shell packaging form is used outside the battery pack, mainly depends on the specific needs of customers. For the packaging form of PVC heat seal, it is generally applicable to the case that the number of series and parallel cells is small and the overall weight is light. However, for the battery pack with an overall weight of ≥ 1kg, it is necessary to add a fixed support between the cells, add glass fiber board on the periphery for protection, and then use PVC heat sealing.
Plastic: plastic shell is adopted, mainly after different battery packs are finalized, the shell involved may need to be opened. Mold cost is not a small expense. For example, in the early stage of development, if the product is not finalized, the hand board shell can be used for proofing. The different material and process requirements of the shell will also affect the cost.
Metal: the metal shell is the same as the plastic shell. Before the product is finalized or the quantity demand is not much. It is recommended to use sheet metal for sample preparation, which is mainly because the sample preparation delivery time is short. If the batch is large, it is also recommended to open the mold. For the metal shell with waterproof grade requirements, it will also greatly affect the cost. There are also requirements for special material metal shell, and the cost will be higher.
The cost of lithium battery is mainly composed of battery cell, PCM and structural parts. In addition, the pack cost, aging cost and management cost of the enterprise need to be added. At the same time, due to the different requirements of product technical difficulty, purchase amount and defect rate, the price of lithium battery will also vary greatly.
Factors affecting the safety of lithium batteries
1. The ambient temperature should not be too high or too low. It is best to work at normal temperature.
2. If you receive a violent impact or puncture, it will immediately cause fire.
3. Excessive discharge greatly reduces the service life of lithium battery.
4. Poor circuit insulation, water inflow, resulting in short circuit, etc.