Ask The Experts: Martyn Sly-Jex, Regional Sales Manager, EMEA, Anton/Bauer
What should I know about the chemistries behind lithium-ion batteries?
When Li-ion cell chemistry was first introduced, it was hailed as a breakthrough, lightweight power solution for broadcast and video professionals. It incorporated high-energy density and low-self-discharge cells, promising superior performance benefits and minimal maintenance. While these new Li-ion cells could maintain their charge longer than other chemistries, if stored for extended periods of time, they would lose capacity and often die. Newer cell technologies have emerged to overcome these inadequacies, providing high-load capacities and substantially longer battery-life expectancy. Today, there are more than 12 different variants of Li-ion, with chemical mixes on anode and cathode material, such as manganese, iron phosphate and cobalt.
It is important to note that the Li-ion electrolyte has a low flashpoint and therefore a low tolerance to overcharge. It can become volatile if over-discharged. Li-ion packs with imbalanced cells, for example, can readily lead to one cell igniting an entire pack. When purchasing batteries, one should look to a manufacturer that invests in high-quality cells from a leading cell manufacturer. High-quality cells are pre-tested and matched for balance, mitigating cell failure and potential hazards.
What is important to know about travelling with my lithium-ion batteries?
Over the past several years, in light of multiple air incidents involving batteries,government and global transportation agencies such as the Federal Aviation Administration (FAA), International Air Transport Association (IATA) and Department of Transportation (DOT) have issued bans and limitations on transporting Li-ion batteries. Li-ion batteries that are considered to be “dangerous goods” are those with more than 160 watt hours (Wh). Li-ion batteries between 101 and 160Wh sometimes incur carry-on and check-in luggage limitations. To ensure customers carry goods that meet international travel standards, all Anton/Bauer batteries are sold with compliable packaging and inspected to U.N. standards—whether they’re classified as dangerous goods or not.
While we recommend that travelers consult the IATA and DOT websites for specifics, we have developed some helpful guidelines, based on IATA regulations, for traveling with Li-ion batteries. In carry-on baggage, you are able to fly with an unlimited amount of batteries under 100Wh. For batteries between 101Wh and 160Wh, passengers are limited to two batteries uninstalled, with any additional batteries required to be installed on a device. It is Anton/Bauer’s recommendation that batteries not installed on equipment be individually protected to prevent short circuits. This requires placing them in the original packaging or otherwise insulating terminals, which can be accomplished by placing tape over terminals or ensuring each battery is packed in a separate plastic bag, for example. Any battery that is 160Wh or more is forbidden as carry-on luggage. When checking batteries, any batteries less than 160Wh must be installed on a device. Again, air travel with batteries 160Wh or more is forbidden. Carry-on and check-in luggage containing Li-ion batteries are ultimately subject to individual airline and TSA approvals.
How can I ensure my Li-ion battery is safe?
It all begins with the investment you make. Well-designed Li-ion-based batteries have built-in safety mechanisms. One such example is the honeycomb cell design, where each individual battery cell is self-contained. This prevents cells that are damaged from damaging adjacent cells, as the thermal heat transfer is minimized. It also protects the person handling the battery by preventing fuel leakage and therefore increasing battery life—a beneficial side effect.
Battery cells also become dangerous when exposed to the heat inherent in the charging process. Overcharging can increase internal cell pressure, causing the cell to vent flammable material. Likewise, ruptured cells can also cause short circuits and subsequent explosions.
Equally important to the quality of the cell itself are the operational cell functions. Each cell has specification ranges that must be maintained, not only to ensure optimal performance, but to prevent failure which, in the case of lithium-ion, can be disastrous. Cells become vulnerable when voltage drops or spikes, or during excessive charging and discharging. In order to prevent potential dangers, leading battery manufacturers incorporate protection circuits that monitor cell activity. The protection circuits will automatically disable a battery if a cell fails and will not resume operation until the operating conditions return to normal. Protection circuits also guard against the pack short circuits and temperature changes that occur when charging, discharging or when environmental conditions such as extreme temperature changes occur. This not only keeps you safe, it also prevents expensive equipment from being damaged.
What are some tips for properly charging Li-ion batteries?
Similar to batteries, not all chargers are created equal. In order for a battery to yield superb performance and ensure safety, it needs a sophisticated charging system that can provide appropriate charge algorithms specific to its chemistry. At Anton/Bauer, we do not recommend mixing chargers and batteries from different manufacturers.
Unsophisticated chargers cannot identify what type of battery they have on board. If the charger simply runs current, it could subsequently heat a potentially explosive electronic device. Not an advisable idea. All Anton/Bauer digital Logic Series® batteries, for example, are able to communicate with the charger, exchanging parameter data, so that the correct charging algorithms can be applied and the relevant charge cut off programs are activated at the correct time. These features ensure the batteries have been charged precisely and to the individual characteristics of a particular battery. Special software and fuel gauging will shut down the battery if it is placed on a charger that it doesn’t recognize, or if the battery is too hot or too cold.
Another feature of a sophisticated charging system is longevity. When it comes to finding a charger that provides longevity, and therefore protects your investment, if the manufacturer of the battery you’re considering claims that it can be used with any type of charger, it’s unlikely the design is sophisticated enough for long-term professional use. Again, the battery may even pose a possible safety hazard. Instead, look for a charger that has two-way communications with the battery and the ability to test and calibrate. It should also have temperature channels and the ability to be upgraded for future algorithms, as technology develops.
In what instances would you recommend a customer select a NiMH battery over a Li-ion one?
As with any production purchase, you must consider your needs, including capacity, load-carrying abilities, charger options and safety mechanisms when making the decision to choose between a nickel-metal hydride (NiMH) and Li-ion battery. The advantages of Li-ion batteries outweigh their drawbacks, so when you’re looking for a lightweight power solution, they are ideal.
High-power NiMH batteries are tried and true, as the NiMH technology behind them is used extensively in rechargeable batteries for consumer electronics such as power tools, back-up battery systems and even electric vehicles. The technology provides maximum battery performance, superior reliability, while also offering a counterbalance and suiting the power demands of today's high definition equipment and on-camera lighting systems, without limits or travel restrictions. Another benefit to the myriad of applications and uses of NiMH, is the technology’s ability to withstand a wide range of climate changes. What’s more, NiMH batteries are able to be fully charged as fast as one hour (depending on the charger) unlike Li-ion batteries.
Understanding the benefits and potential hazards or restrictions of batteries—not to mention the safety provisions available to address them—can help you make an informed decision when investing in a quality battery.