18650 7.4V 4400mAh Small Lithium Battery

7.4V lithium battery pack belongs to the multi-series parallel lithium battery pack, its application are as following:

• Communication equipment:

Cordless phones, mobile phones, fax machines, mobile POS machines

• Audiovisual equipment:

Video cameras, portable stereos, MD players, portable DVD and VCD players, wireless speakers

• Electronic equipment:

Laptops/Tablets/Netbooks, PDAs, Portable Printers, Smart Vacuum Cleaners, GPS Navigators

• Industrial instrument:

Flaw detectors, laser detectors, atmospheric samplers, water quality detectors, laser pointers, fiber optic fusion splicers, frequency selection and leveling meters, etc.

• Medical instruments:

Monitors, ECG machines, B-ultrasound machines, ventilators, laser blood collection machines, etc.

Assemble lithium batteries first in parallel or in series?

• Lithium battery pack series-parallel topology
  
  The typical connection methods for forming a lithium battery pack include parallel connection first and then series connection, series connection first and then parallel connection method, and mixed connection method.
  Lithium battery packs for pure electric buses are usually connected in parallel first and then in series.
  Lithium battery packs for grid energy storage are often connected in series and then in parallel.
• The advantages of lithium batteries in parallel first and then in series

  The lithium battery will automatically exit when it fails, except for the capacity reduction, it will not affect the use after parallel connection;
  When a lithium battery cell in parallel is short-circuited, the parallel circuit current is very large, which is usually avoided by adding fusing protection technology.
  
  

• Disadvantages of lithium batteries in parallel first and then in series

  Due to the difference in the internal resistance of the lithium battery cells and the uneven heat dissipation, the cycle life of the lithium battery pack after being connected in parallel will be affected.
  
  

• The advantages of lithium batteries in series first and then in parallel

  According to the lithium battery cell capacity, first connect in series, such as 1/3 of the capacity of the whole group, and finally connect in parallel, which reduces the failure probability of large-capacity lithium battery modules.