This is between 20 and 80 mΩ. The chemical composition capacity of ordinary 18650 model cylindrical lithium batteries commonly seen in the market is generally around 150 mAh/g, while the negative pressure value depends on different manufacturers and models and is approximately between 20 and 80 mΩ. The chemical capacity of a lithium battery refers to the amount of charge a battery can store, usually expressed in mAh/g per unit area.
How to assemble lithium batteries yourself
With the rapid development of electric vehicles and automobiles, vehicle power sources are also developing rapidly, but There are problems in battery production. Many problems have made the quality of battery products on the market very uneven. The capacity and life of the battery in the later period cannot reach the expected lifeeu. This has a lot to do with unique production. battery process in production.
The battery structure consists of an outer casing, a top cover, pole plates, separators, bus bars, poles, bridge protection plates, terminals and other components.
The processes of each lithium battery manufacturer have some differences, but they remain the same. The main processes are: batch processing, coating, rolling, cutting, slitting, tab welding and winding. baking, liquid injection, forming, molding, volume separation and testing.
The time for each step is different. Generally, the ingredients, cooking and processing time are relatively long, which can take 10 to 48 hours. Other processes are faster, taking 4 to 8 hours. It will take around 15 days in total.
Why the rIs the internal resistance of lithium batteries less than the capacity after training?
1. Sludge making:Use special solvents and binders to mix the positive and negative active materials into powder respectively, and stir evenly to form positive and negative form slurry. materials.
2. Coating film:The positive and negative electrode slurries are evenly coated on the surface of the metal sheet through a dynamic coating machine, then dynamically dried and then positive sheared. and negative pole pieces.
3. Assembly:In the order positive electrode sheet - separator - negative electrode sheet - separator from top to bottom, the processes include winding, electrolyte injection, sealing and welding. of positive and negative electrode tabs, i.e. complete the assembly processage of the battery and manufacture the finished battery.
4. Training:Put the finished battery into the testing cabinet for charging and discharging testing, and select qualified finished batteries before leaving the factory.
Notes on lithium batteries:
Firstly, lithium-ion batteries can be seen everywhere in people's lives, including various portable electronic products, vehicle GPS, etc. . Lithium-ion batteries have become tools to maintain these important parts of the operation. Keeping lithium-ion batteries properly charged and discharged can extend battery life. Keeping the lithium-ion battery power between 10% and 90% is beneficial to protect the battery. This means that when charging batteries of digital products such as mobile phones and laptops, it is not necessary to reach the maximum value.
If digital products with lithium-ion batteries are exposed to sunlight or stored in hot cars, it is best to keep them. Some products are discontinued because lithium-ion batteries age faster if the operating temperature exceeds 60 degrees Celsius. Lithium battery charging temperature range: 0 ~ 45 degrees Celsius, lithium battery discharge temperature range 0 ~ 60 degrees Celsius.
Second, if the cell phone battery needs to be charged every day, the reason may be that the battery is defective or it is time to "retire".
For laptop owners, it is best to remove the battery if it is plugged in for a long time (the high heat generated by the computer while in use is not good for the battery of the laptop).
Third, under normal circumstances, a power of50% is the most conducive to the preservation of lithium-ion batteries.
The formation process of lithium batteries generally requires an amount of current and how long it takes.
The internal resistance of cylindrical lithium-ion batteries changes significantly (14,500) after training. . The internal resistance is several tens or even hundreds of milliohms, higher than before. In some cases, the internal resistance after training is lower than before training. What are the reasons? THANKS. This is not a manufacturing problem. Most batteries in the same batch are normal. Use 0.2C to charge and discharge lithium iron phosphate.
How lithium batteries are made
Small battery: charge from 0.2C to 4, 1V
Large battery: 0.05C is charged to 3.45V; 0.1 C is charged to 3.95 V; 0.2 C is charged to 3.95 V.
It is necessary to charge with a psmall common at first, as this is the initial training process. from the movie SEI. After that, the current can be slightly increased.
Step 1: Ingredients
Fully automatic stirring of the materials under high vacuum for 10 hours to evenly disperse the materials needed for lithium batteries and improve consistency. and consistency of overall battery performance. Why are you doing this? Since ingredients are the core of lithium battery production, poor quality ingredients directly affect the performance of lithium batteries.
Step 2: Coating
Use automatic feeding system, automatic knife adjustment system and online thickness measuring system to evenly coat the positive and negative. Why are you doing this? The coating being the basis of the production of lithium batteries, it determines the consistency of the batterie.
Step 3: Aligning the rollers
After the positive and negative electrode sheets are covered, the positive and negative materials are relatively loose and some pressure must be applied to the sheets of electrodes to compact the positive and negative electrode materials within a certain range.
Step 4: Splitting
Depending on the battery model, the positive and negative electrode plates need to be cut into the required widths. For example, in an 18650 lithium battery, the width of the pole piece is between 56 and 58 mm.
Step 5: Filming and winding
Use a fully automatic filmmaking machine to weld the positive and negative electrode tabs to the positive and negative electrode sheets. A fully automatic winding machine is used to wind the positive and negative electrode sheets and separator together into a fcylindrical elm.
Step 6: Bottom rolling groove and vacuum drying
Put the core into the steel shell, automatically weld the negative electrode tab, and automatically roll the groove. In addition, it is fired under high vacuum and high temperature to dry out a small amount of moisture, so that the performance of the lithium battery can be guaranteed.
Step 7: Composition and Composition
Lithium batteries need to be treated before shipment.Perform charge and discharge test. The battery is charged before leaving the factory.
Step 8: Assemble the lithium battery
Fully automatic welding machine, weld multiple battery combinations with connection sheets, then install the circuit board and carry out aging tests and inspections. Shipping.
In brief, the production process of lithium batteries for electric vehicles of haute quality is very rigorous, because only in this way can its quality be guaranteed. For users, they should be more careful when choosing lithium batteries and not be greedy for cheap to avoid encountering inferior lithium batteries.