First, price composition of lithium battery pack
The price of lithium battery is mainly composed of three parts: battery cell, protection plate and outer case. At the same time, due to the power consumption and current of electrical appliances, the selection of materials of connecting sheet(conventional nickel sheet, molded nickel sheet, copper-nickel composite sheet, jumper sheet, etc.) between battery cells will affect the cost. Different connectors (such as aviation plug, From USD5/pcs to USD300/pcs) may also have a great impact on the cost, and different Pack processes will also affect the cost.
Second, the influencing factors of the price of lithium battery pack
1.Cell selection
cell selection of different material systems will affect the price of the whole lithium battery pack. According to the different cathode materials of lithium battery, there will be lithium manganate(LMO) (3.6V), lithium cobalt acid (3.7V/3.8V), lithium nickel-cobalt manganate (commonly known as ternary,3.6V), lithium iron phosphate(LFP) (3.2V), lithium titanate(LTO) (2.3V/2.4V) and other material systems of the cell, Its voltage platform, safety factor, cycle times, energy density ratio, working temperature and so on are different. The price of different brands of cell will also vary greatly. The total price gradient can be divided into: Special batteries (including temperature, super high temperature, super high rate, alien), Japanese (panasonic, sanyo, SONY), South Korea (Samsung, LG), China (CTAL,BYD,CALB or some others), the material system and different brands of batteries, the price difference will be very big. And through the market survival of the fittest out the quality of each brand cell (safety, consistency, stability) is basically proportional to the price.
2.Requirements and design of lithium battery pack PCM
PCM design can be divided into: basic protection, communication, BMS
Basic protection: Basic protection includes over charge, 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 and so on. There is also a simple electric quantity display, which can be used by charging meter and LED indicator.
BMS: BMS is the first letter of BATTERY MANAGEMENT SYSTEM abbreviation combination, commonly known as battery nanny or battery housekeeper, mainly in order to intelligent management and maintenance of each battery unit, to prevent the battery overcharge and overdischarge, prolong the service life of the battery, monitoring 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. This system is mostly used in Power battery pack.
3.Requirements and design of the outer case of lithium battery pack
Lithium battery pack outer case design can be divided into: PVC heat seal case, plastic case and metal case.
PVC heat seal case: the outer case packaging form of the battery pack is mainly dependent on the specific needs of customers. For the packaging form of PVC heat seal, it is generally applicable to the battery string and the number is not much, the overall weight is light (≤2kg), under these conditions it can be used. However, for the battery pack with the overall weight ≥1kg, it is necessary to add a fixed bracket between the battery cells, and then use PVC heat seal after adding a glass fiber board to protect the periphery.
Plastic case: Plastic outer case, mainly different battery pack after finalize the design, involving case may need to build a new mold, mold fee is a lot of money, such as the early stage of the development, the product did not finalize the design, can use hand-made case proofing (the strength of hand-made is less much than mold production), the material and process of case (especially requirements of waterproof,dust-proof and salt-fog-proof), will also affect the cost.
Metal case: metal case is the same as plastic case in mold requirement, the product is not confirmed before batch production, it is recommended to use hand-made sample, because the delivery time of hand-made metal case is short, but if all details confirmed and batch production, also recommended to build a mold. For the metal case has waterproof grade requirements, will also greatly affect the cost. there is a special material requirement for metal case (such as titanium alloy, etc.), the cost will be higher.
The cost of lithium battery pack is mainly composed of cell, PCM and structural parts. In addition, pack cost, aging cost and management cost of the enterprise should be added. At the same time, due to the technical difficulty of the product, the purchase amount, defective rate of different requirements, the price of lithium battery pack will be very different!
