By Battery Engineering Team – Epec Engineered Technologies
In today's battery and charger market companies may provide either battery assemblies or battery chargers, but few provide both. In the past buying a battery from one source and a charger from another worked just fine when using the older NiCd batteries with overnight chargers. However, with today’s new battery chemistries and the increasing need for faster charge times, careful matching of the charger to the battery is essential. Without proper matching, safety, cycle life, or run-time may be greatly affected.
Fast-charging NiCd batteries at rates of 1C to 4C, safety can be an issue. In these high-current applications, battery temperature must be monitored electronically, so precise control of the charger can be obtained. Once the battery is fully charged, the high-charge rate must be reduced to prevent the battery from going into thermal runaway and venting.
The end result is improved time-to-market, reduced development cost, and a finely tuned battery and charger system. The ultimate benefit is that the customer can concentrate on their core competency, which will ultimately affect the competitiveness of their end product in the marketplace.
Feel free to visit our Battery Pack Development Timeline for additional information on process expectancy.
In today's battery and charger market companies may provide either battery assemblies or battery chargers, but few provide both. In the past buying a battery from one source and a charger from another worked just fine when using the older NiCd batteries with overnight chargers. However, with today’s new battery chemistries and the increasing need for faster charge times, careful matching of the charger to the battery is essential. Without proper matching, safety, cycle life, or run-time may be greatly affected.
Fast-charging NiCd batteries at rates of 1C to 4C, safety can be an issue. In these high-current applications, battery temperature must be monitored electronically, so precise control of the charger can be obtained. Once the battery is fully charged, the high-charge rate must be reduced to prevent the battery from going into thermal runaway and venting.
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| Lithium Polymer Pack & Custom Charger |
Charger Impact on Battery Cycle Life
Cycle life can be impacted by treating batteries from different battery manufacturers in the same manner. While there are numerous manufacturers providing Li-lon and NiMH batteries, this doesn’t mean they should all be treated the same way. Inspection of the manufacturer's data sheet revealed that some types of NiMH batteries can take a continuous C/1O overcharge, while the most popular types of NiMH batteries cannot take this type of overcharge without severely affecting the cycle life of the battery. Precaution must be taken to understand the difference between the various manufacturers of Li-Ion batteries and how these differences affect the charging characteristics of their batteries. Some manufacturers require 4.1Vlcell charge voltage while others require 4.15 V/cell or 4.2 V/cell charge. If these voltages are exceeded by as much as 50mV, the battery will overcharge affecting the cycle life of the battery and causing safety issues.Insufficient Battery Run Times
Insufficient run time is caused by undercharging the battery, which can happen by misapplying technology. An example would be the charging of a 4.2 V/cell Li-Ion battery using a 4.1 V/cell Li-Ion charger or by not fully characterizing the system dynamics. Some early termination problems can be caused by system noise by operating outside the temperature range of the battery or by using a mismatched thermistor in the battery pack. The only way to insure the battery and charger are matched correctly is to buy the whole unit from one source that has the expertise in designing and providing fully custom battery assemblies and fully custom chargers to meet the requirements of the customer.Sourcing a Complete Battery, Charger, and Power Solutions
This "one stop shop" approach to battery and chargers can be extremely beneficial to the source purchasing the batteries and chargers. Primarily, if the battery and charger are ordered from two different sources, the customer will need to coordinate the design of both the battery and charger. This may require the customer to have expertise on batteries, chargers, and inherent safety devices. This is especially true in the newer Li-Ion or NiMH technologies are implemented using a fast charger and fuel-gauge. If the overall battery and charger system does not work, who will take the blame? Ultimately, it will be the responsibility of the customer to determine if the battery or charger or both are at fault. Since the two sources that provided the equipment may be reluctant to change their designs, the intervention of a third engineering party may be required. This can prove costly. By using a source that specializes in providing complete battery, charger, and power solutions, the customer only needs to provide the overall system performance requirements, and the engineers at the "one-stop shop" will work out all the engineering details.The end result is improved time-to-market, reduced development cost, and a finely tuned battery and charger system. The ultimate benefit is that the customer can concentrate on their core competency, which will ultimately affect the competitiveness of their end product in the marketplace.
Feel free to visit our Battery Pack Development Timeline for additional information on process expectancy.