Frequently Asked Questions

▣ Does VARTA Microbattery provide custom battery pack solutions?

Yes.  Our innovative battery pack solutions span a variety of chemistries, and support all major markets including medical, commercial and consumer electronics. Using our technology expertise, innovative and flexible engineering, comprehensive testing and efficient manufacturing capabilities, we help our customers meet any power challenge

▣ What is the difference between Lithium batteries and Lithium Ion batteries?

There are several important differences. The practical difference between Lithium batteries and Lithium-ion (Li-ion) batteries is that most Lithium batteries are not rechargeable but Li-ion batteries are rechargeable.  From a chemical standpoint Lithium batteries use lithium in its pure metallic form.  Li-ion batteries use lithium compounds which are much more stable than the elemental lithium used in lithium batteries. A lithium battery should never be recharged while lithium-ion batteries are designed to be recharged hundreds of times.

▣ Do NiMH batteries have memory effect?

NiMH batteries do not have a "memory effect".  However NiMH batteries can experience what is known as "voltage depression", similar to NiCd batteries, but the effect is generally less noticeable.  To eliminate the possibility of NiMH batteries suffering voltage depression manufacturers recommend an occasional, complete discharge of NiMH batteries followed by a full recharge. NiMH batteries can also be damaged by overcharge and improper storage. Most users of NiMH batteries don't have to be concerned with this voltage depression effect, but if you use a device for only a short period of time every day, and then charge the batteries every night, you will need to let the NiMH batteries run down occasionally to keep this effect from occurring.

▣ What are the differences in capacity loss (self-discharge) during storage between NiMH & Li-Ion batteries?

NiMH batteries will lose approximately 20% of their available capacity after the first month of storage, and about 40% of their available capacity after 12 months of storage at room temperature.  Li-Ion batteries will lose approximately 10% of their available capacity after the first month of storage, and about 20% of their available capacity after 12 months of storage at room temperature.

▣ What is the definition of "Capacity" related to a battery?

Capacity is the measure of the energy stored in a battery. Expressed in Ah (Ampere hour) or mAh (milli-Ampere hour), capacity defines the ability of a battery to perform  under specified discharge criteria over a set period of time.


▣ What is the best way to store Lithium Ion batteries?

Lithium Ion batteries are able to hold a charge for many months. It is best to store a lithium-ion battery with a partial or full charge. If a lithium-ion battery with a very low charge is stored for a long period of time its voltage can drop below the level at which its built in safety mechanism allows it to be charged again.  If the battery is going to be stored for several months it's a good idea to take it out and recharge it after a few months.  It would be even better to actually use the battery every few months and then leave it partially or fully charged.

▣ Can VARTA assist with the certification required to meet UN 38.3 Lithium Transportation Regulations?

Yes.  VARTA Microbattery can provide assistance in managing the testing and certification required to meet the UN 38.3 Lithium Transportation Regulations.  VARTA Microbattery can also assist in the completion of regulatory compliance testing used for individual cells and custom battery packs (UL1642, UL2054, IEC62133 & others).

▣ What are the advantages and disadvantages of Bobbin constructed lithium cells?

Advantages: Bobbin constructed lithium primary cells are very good at providing a shelf life (they have a low self discharge rate), and they also provide very high capacity  which means longer runtimes (the construction is capable of storing a large amount of electrolyte).

Disadvantages: The bobbin construction makes for a smaller electrode  surface area which results in higher internal resistance, and this in-turn limits the amount  of current the cells can deliver.  This makes the bobbin cell construction poor for  applications requiring higher discharge rates.