Lithium Ion (Li-Ion) vs Nickel Cadmium (NiCd)

Which Battery Pack is Best?

Cordless tools have come so far in design that today most any tool can be purchased in a cordless version. With so many choices in tools and manufacturers it’s no wonder that consumers feel overwhelmed. Add to the equation all of the choices in battery packs and it’s not out of the question to become frustrated. Here at HCI we’ve tested so many cordless tools that we thought some clarification and shared experiences might be useful to many of you.

One of the biggest questions that we’ve seen lately is from users asking us which battery pack is best: Lithium Ion (Li-Ion) or Nickel Cadmium (NiCd). There is another choice; Nickel Metal Hydride (NiMH), but they are less popular and not covered in this discussion.

Another point worth mentioning is that each manufacturer uses their own design for these batteries typically which can result in some variation in performance. It also means that some manufacturers may be more prone to some issues while others may have found a better design.

The following is a very brief and generic description of the battery types along with general pros and cons.

Lithium Ion Batteries

Lithium Ion (Li-Ion) batteries use lithium ions move from the negative electrode to the positive electrode during discharge, and back when charging (ref). Lithium Ion batteries have become one of the most popular battery options for cordless tools in the last few years for several reasons including lighter weight and no memory effect. The following are pros and cons for Li-Ion Batteries.

Pros:

• Light weight to and small size allows almost any size to fit tools more proportionally.
• No memory effect.
• Increased life cycles compared to Nickel Cadmium batteries.
• Shelf Life – Li-Ion batteries dissipate power much less rapidly over time even when sitting idle.
• Higher power output at lower currents compared to NiCd batteries.
• Little if any voltage drop when the battery is near the end of it’s discharge cycle.

Cons:

• Newer technology that’s not been tested and developed as much as other battery systems.
• Can run very hot and even suffer from thermal runaway and eruption if mishandled.

Nickel Cadmium Batteries

Nickel Cadmium Batteries (NiCd or NiCad) are a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. NiCd batteries have been the workhorse of cordless tools for many years and continue to sell well in this Country. Over the last few years they have been pressured by the introduction of comparable Li-Ion batteries.

Pros:

• NiCd batteries are much more durable and less likely to be damaged during the charge and discharge process.
• Performs better at lower temperatures

Cons:

• Higher cost
• Battery uses cadmium (health/environmental concerns)
• Heavier
• Can develop a memory (from continued charging without fully discharging)

Battery Chargers

Couple of issues are worth discussing when it comes to charging lithium-ion batteries.

• Li-Ion batteries MUST be charged using a Li-Ion charger. These chargers typically have special circuitry and cooling fans required to optimize the charge and keep the batteries cool.
• Some older NiCd batteries can actually be charged in the newer Li-Ion battery chargers. Older NiCd battery chargers WILL NOT charge newer Li-Ion batteries.

Battery Sizes

It’s also very important to be sure you’re using the correct size batteries. Many manufacturers are producing compact and full size battery packs in some of the voltages. For instance DeWalt makes the compact and XRP versions (typically 1.8 and 2.6 mAh respectively). This just represents how long the battery will last and how heavy they are.

Cordless Battery Dilema

So the question of the day is which battery is better? Honestly I think the verdict is still out and when you talk to industry representatives most of them plan to continue building cordless tools on both platforms. Recently it surely appears to us that Li-Ion is starting to take the lead at least with new tool launches. However, until the Li-Ion batteries better deal with low temperatures (working here in New England during the winter is a fine example) it’s likely that NiCd will continue to sell just as well. Keep these tips in mind when you buy cordless batteries.