Composition of lithium battery price
Lithium battery price is mainly composed of three main parts: battery core, protection plate and casing. At the same time, due to power consumption and battery current. electrical appliances used, the impact on the battery core The choice of materials for connecting parts (conventional nickel sheets, formed nickel sheets, copper-nickel composite sheets, jumper sheets, etc.) will affect the cost of different connectors (such as aviation). sheets, ranging from more than ten yuan to thousands of yuan) Both) can also have a greater impact on costs, and different PACK processes will also affect costs.
Factors affecting the price of lithium batteries
1. Battery cell selection:
First, the selection of battery cells in different ma systemsmaterial will affect the whole. Lithium battery industry. According to the cathode material, lithium batteries include lithium manganate (3.6V), lithium cobalt oxide (3.7V/3.8V), lithium nickel cobalt manganate (commonly called ternary, 3.6 V) and lithium iron phosphate (3.2 V). , lithium titanate (2.3V/2.4V) and other battery cells with different material systems. Voltage platform, safety factor, number of cycles, energy density ratio, operating temperature, etc. Batteries with different material systems are different.
Second, the prices of battery cells from different brands also vary greatly. The overall price gradient can be divided into: special battery cells (including ultra-low temperature, ultra-high temperature and ultra-high magnification). , and special shapes), Japanese (Panasonic), Sanyo, Sony),Korean (Samsung, LG), domestic (domestic is divided into first line (Lishen, BAK, BYD, ATL), second line and even fifth-line and sixth line), with the same hardware system. The price difference between different brands of battery cells will be very large, and the quality (safety, consistency, stability) of each brand of battery cells will be eliminated through the survival of the fittest in the market is basically directly proportional to the price.
2. Requirements and design of lithium battery PCM
PCM design can be divided into: basic protection, communication, BMS
Basic protection: basic protection includes overcharge . , over-discharge, over-current and short-circuit protection, over-heat protection, etc. can be added according to product requirements
Communication: Communication protocols can be divided into I2C, RS485, RS232,CANBUS, HDQ, SMBUS, etc., as well as simple For power display, a fuel gauge can be used for LED indication.
BMS: BMS is the first abbreviation of BATTERY MANAGEMENT SYSTEM. It is called battery management system. He is commonly referred to as a battery nanny or battery butler. It is mainly intended for intelligent management and maintenance of each battery. Unit to avoid battery failure. In case of overcharging and overdischarging, extend battery life and monitor its condition. Its main functions include: real-time monitoring of battery physical parameters; estimation of battery status; online diagnosis and early warning; managing the balance of charge, discharge and precharge; The subsystems are mainly used in electric vehicle batteries.
3. Battery box application and designe lithium
Lithium battery box design can be divided into: PVC heat sealing, plastic, metal
PVC heat sealing: battery What specific methods are used in outside the group?The blister packaging form mainly depends on the specific needs of the customer. PVC heat sealed packaging form is generally applicable when the number of cells in series and parallel is small and the total weight is light (≤2kg). However, for batteries with a total weight ≥1kg, it is necessary to add fixed supports between cells, add fiberglass panels at the periphery for protection, and then use heat sealing in PVC.
Plastic: Use a plastic case, mainly because once the various battery packs are finalized, the affected case may need to be molded. The cost of the mold represents a significant expense if the product is not finalizedat first. development, you can use a prototype shell for testing (the strength of the prototype is not as good as the strength of the material once the mold is opened and finalized). Hull material and process requirements (especially three-proof requirements). ) are different, which 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 large, it is recommended to use sheet metal sample preparation. This is mainly due to sample preparation. and the delivery time is shorter. If the batch size is large, it is also recommended to open a mold. If the metal casing has waterproof requirements, it will also greatly affect the cost. There are also requirements for metal enclosures made from special materials (such asue titanium alloy, etc.), and the cost will be even higher.
The cost of lithium batteries is mainly composed of battery cells, PCM and structural parts. Added to this are the company's PACK fees, aging fees, management fees, etc. At the same time, due to the different technical difficulties of products, purchasing volume and defect rate requirements, the prices of lithium batteries will also vary greatly.
What are the four used for? lithium battery connectors?
Simple and practical solution: make two strings of lithium batteries, first connect 20-30 lithium batteries in parallel, then connect two large batteries in series. The protective panel may or may not be removed. is removed, install two strings of lithium batteries for the protection board, you can also keep the battery protection boarde original and add two sets of protective panels.
For voltage output, use a DC-DC module, and for 5V, use a step-down board of 6-12V input and 5V output. The output current is about 3 A, or 1 A. easy to find. Use USB output, used to charge mobile phones. For 9-12V you can use a booster board. The input is 6-9V and the output is 9V or 12V. It is best to separate the two fast cards. You can also find one with adjustable output voltage, but this is not the case. recommended. If you adjust it incorrectly, it can burn the equipment. So split it up, the output current is 1-2A, which is almost enough to power routers and cats. It is best to add independent input switches to all three boards to prevent static power consumption from causing the board to fail.
The charging part uses a battery chargerie two-string 8.4V lithium, and the advanced point uses 2S balance charging to reduce series overload. Balance charging may have to be homemade, but it is also simple. Lithium batteries can be charged independently. There is also a simple and effective solution, using parallel charging and serial discharge connectors. The specific method is to connect the positive and negative poles of two parallel lithium batteries to a 4-core anti-reverse socket. , then connect them in series to the socket. The connection wires must be connected in parallel. Create another outlet and connect them in parallel. The advantage is that the load is absolutely balanced. You only need one lithium charger, which is everywhere. the street. The downside is that charging and discharging cannot be done at the same time and you have to switch manually. But you are a backup, the advantages outweigh the disadvantages.The first method is to use a double-pole, double-pole switch to switch between series and parallel. The effect is the same, but the wiring is more complicated.
Note: The parallel battery connection wire should be thicker. The battery has a large capacity. If the charging current is small, it will take a long time and the current should not be too small. For example, if the capacity is 10 Ah, the load should not be less than 1 A. Depending on your situation, it should not be less than 2 A. If possible, divide the battery capacity so that you get the capacity of both. the battery packs are as close as possible. For the selection of parallel charging and serial discharge connectors, four-conductor aviation plugs are more suitable. They are a non-reverse connection and can handle excessive current. A set and a half is needed. The chSimple high current lithium batteries are hard to find, so you may need to make your own.
I guess you can only tell by disassembling the case, because there might be a network that takes up two pins for high current, and it might also contain other interfaces to sense the signals, but it cannot be a balanced load interface (because the S number is too large).
You can also purchase a special T-type adapter and use a multimeter to test which wires are connected.