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 Advantages

  • High energy density  potential for yet higher capacities.
  • Does not need prolonged priming when new. One regular charge is all that's needed.
  • Relatively low self-discharge self-discharge is less than half that of nickel-based batteries.
  • Low Maintenance no periodic discharge is needed; there is no memory.
  • Specialty cells can provide very high current to applications such as power tools.

 Limitations

  • Requires protection circuit to maintain voltage and current within safe limits.
  • Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.

If you have any other questions or requirements for lithium ion cells or customized lithium ion battery packs feel free to contact us via the Contact Us form or at the phone number                                  

Lithium Ion Cell / Battery

The energy density of lithium-ion is typically twice that of the standard nickel-cadmium. There is potential for higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium in terms of discharge. The high cell voltage of 3.6 volts allows battery pack designs with only one cell. Most of today's mobile phones run on a single cell. A nickel-based pack would require three 1.2-volt cells connected in series.

 

Lithium-ion is a low maintenance battery, an advantage that most other chemistries cannot claim. There is no memory and no scheduled cycling is required to prolong the battery's life. In addition, the self-discharge is less than half compared to nickel-cadmium, making lithium-ion well suited for modern fuel gauge applications.

 

Despite its overall advantages, lithium-ion has its drawbacks. It is fragile and requires a protection circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge. In addition, the cell temperature is monitored to prevent temperature extremes.

 

Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every six months or so. With such rapid progress, it is difficult to assess how well the revised battery will age. 

 

Storage in a cool place slows the aging process of lithium-ion (and other chemistries). Manufacturers recommend storage temperatures of 15°C (59°F). In addition, the battery should be partially charged during storage. The manufacturer recommends a 40% charge.

 

The most economical lithium-ion battery in terms of cost-to-energy ratio is the cylindrical 18650 (size is 18mm x 65.2mm). This cell is used for mobile computing and other applications that do not demand ultra-thin geometry. If a slim pack is required, the prismatic lithium-ion cell is the best choice. These cells come at a higher cost in terms of stored energy.

 

 


 

 Advantages

  • Very low profile batteries resembling the profile of a credit card are feasible.
  • Flexible form factor manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.
  • Lightweight gelled electrolytes enable simplified packaging by eliminating the metal shell.
  • Improved safety more resistant to overcharge; less chance for electrolyte leakage.

Limitations

  • Expensive to manufacture.
  • No standard sizes. Most cells are produced for high volume consumer markets.
  • Higher cost-to-energy ratio than lithium-ion

If you have any other questions or requirements for lithium polymer cell or customized lithium polymer battery pack feel free to contact us via the Contact Us form or Call Us On +91-44-45587022 / +91-9884851940                              

Lithium Polymer Cell / Battery

The lithium-polymer differentiates itself from conventional battery systems in the type of electrolyte used. The original design, dating back to the 1970s, uses a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that does not conduct electricity but allows ions exchange (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.

The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry. With a cell thickness measuring as little as one millimeter (0.039 inches), equipment designers are left to their own imagination in terms of form, shape and size. 

To compromise, some gelled electrolyte has been added. The commercial cells use a separator/ electrolyte membrane prepared from the same traditional porous polyethylene or polypropylene separator filled with a polymer, which gels upon filling with the liquid electrolyte. Thus the commercial lithium-ion polymer cells are very similar in chemistry and materials to their liquid electrolyte counter parts. 

Lithium-ion-polymer has not caught on as quickly as some analysts had expected. Its superiority to other systems and low manufacturing costs has not been realized. No improvements in capacity gains are achieved - in fact, the capacity is slightly less than that of the standard lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, such as batteries for credit cards and other such applications.


 

Protection Circuit Module

 

The protection circuits are contained in what is commonly referred to as the Protection Circuit Module (PCM). While there are many off the shelf PCMs that you can buy, each individual application requires unique parameters are maintained so it is not recommended that these off the shelf modules are used for anything.

The primary safety circuits manage all the basic safety functions: over-voltage, under-voltage, over-current and sometimes over and under temperature. Additionally, most of the world class designs also include a secondary safety circuit which is there to protect the cell from charge in the event the primary safety circuit fails.

Battery protection circuits for the most demanding applications are operated mostly by Integrated Circuits (ICs) typically using MOSFETs to switch lithium cells in and out of circuit. The over-current protection is normally provided when the IC detects the upper current limit of the battery being reached and then interrupts the circuit.

If you have any other questions or requirements for Protection Circuit Module feel free to contact us via the Contact Us form or at the phone number


 

 Battery Management System

A BMS (Battery Management System) is essential in a Lithium-Ion battery system. This device manages a real-time control of each battery cell, communicates with external devices, manages SOC calculation, measures temperature and voltage, etc. (see key features on the right bar). The choice of BMS determines the quality and lifespan of the final battery pack.

Several types of BMS can be used depending on the intended application and desired features.

Centralized BMS typology for medium power applications (electric bikes, scooters, etc.). For stationary batteries or high power batteries, distributed or master-slave BMS can be also managed.

BMS that we use have been selected for their quality, technical performance, robustness and low power consumption. Battery pack assembly and BMS programming and installation is made in our workshops.

If you have any other questions or requirements for Battery Management System feel free to contact us via the Contact Us form or at the phone number

 


 

Charging lithium batteries can be split into two main stages:

Constant current charge:   In the first stage of charging a lithium battery or cell, the charge current is controlled. Typically this will be between 0.5C and 1.0 C, during this stage the voltage across the lithium cell/battery increases for the constant current charge. The charge time may be around an hour for this stage.

 

Saturation charge:   After a time the voltage peaks at 4.2 Volts per cell. At this point the cell or battery must enter a second stage of charging known as the saturation charge. A constant voltage of 4.2 volts per cell is maintained and the current will steadily fall. The end of the charge cycle is reached when the current falls to around 10% of the rated current. The charge time may be around two hours for this stage dependent upon the type of cell and the manufacturer, etc..

The charge efficiency, i.e. the amount of charge retained by the battery or cell against the amount of charge entering the cell is high. Charge efficiencies of around 95 to 99% can be achieved. This reflects into relatively low levels of cell temperature rise.

If you have any other questions or requirements for Battery Management System feel free to contact us via the Contact Us form or at the phone number

 

Lithium Battery Charger

Lithium ion / polymer, Li-ion / Lithium-polymer batteries offer an excellent level of performance. To gain the best from them, they must be charged correctly.

If lithium battery charging is not undertaken in the proper manner, the battery operation can be impaired and they can even be destroyed - so care msut be taken.

Proper charging of Lithium batteries enables the best performance and longest operational life to be obtained. As a result, lithium battery charging is normally undertaken in conjunction with a battery management system. This controls the level of charge, discharge and the rates at which these can occur.

Lithium battery basics

Charging lithium batteries is very different to charging Ni-Cads or NiMH batteries.

Charging lithium batteries is voltage sensitive rather than current based. Charging lithium batteries is more akin to charging lead acid batteries.

Differences are found in that the lithium batteries have a higher voltage per cell. They also require much tighter voltage tolerance on detecting full charge and once fully charged they do not allow or require to be trickle or float charged. It is particularly important to be able to detect the full charge state accurately because lithium batteries do not tolerate overcharging.

Most consumer orientated lithium batteries charge to a voltage of 4.2 volts per cell and this has a tolerance of around ± 50 mV per cell. Charging beyond this causes stress to the cell and results in oxidation that reduces service life and capacity. It can also cause safety issues as well.