Types of Power Battery

Backup power batteries are the lifeline for critical appliances when a hazard or a power outage occurs. They help businesses keep operations running smoothly during outages and emergencies.

Batteries allow you to rely less on the traditional grid, reducing your peak demand charges on your electricity bill. They also facilitate renewable energy sources like solar and wind.

High-Energy Batteries

Batteries come in a variety of shapes and sizes to suit different devices. However, they all share one thing: the power to deliver energy. To produce that power, battery electrodes accept and release electrons in an electrolyte to drive the chemical reaction that generates electricity.

The more electrons a battery can accept and release, the higher its energy density. This characteristic is often measured in mAh (milliampere-hours) and is the key Power Battery factor to consider when choosing batteries for your needs.

AA alkaline batteries, for example, can sustain a device that draws 250 mA of current for 10 hours and are available in several mAh capacities. The higher the mAh number, the more energy the battery can hold and the longer it will retain its charge.

Nickel-metal hydride, or NiMH, batteries are a common choice for cordless phones and digital cameras because of their low cost, high energy storage capacity and the absence of toxic materials like cadmium. They are also known for their ability to maintain a steady voltage over time, making them a great choice for flashlights and other high drain devices.

Lithium-sulfur batteries, which lack the critical materials found in graphite anodes, offer promise for electric vehicles by storing twice as much energy as batteries on store shelves today. PNNL researchers are working to help bring this promising technology to real-world applications.

Lithium-Ion Batteries

Compared to alkaline, nickel-cadmium and lead-acid batteries, lithium-ion batteries store much more energy per kilogram. This is because of how they are constructed and because the chemistry inside them is different.

Lithium ions are stored (intercalated) in both the anode and cathode materials of a lithium-ion battery. This happens because the ions are small enough to fit in between the 2D layers of graphene that make up bulk graphite. They also have a positive charge, which is why they are able to attract and tie to electrons from the anode. When the lithium ions are de-intercalated during discharge, they release their positive charge. This enables them to travel through the electrolyte to the cathode where they are re-attached to their negative charge and create the electric current that we use.

The anode of a lithium-ion battery contains a combination of manganese, nickel and cobalt. The chemistry is designed to maximize efficiency. The nickel promotes ion flow and prevents the battery from overheating, while the manganese and cobalt stabilize it. Lithium-ion batteries are very durable and a good choice for power tools, e-bikes and other applications with high discharge rates.

The only drawback is that a lithium battery may explode if damaged or overheated. Because of this, they are not allowed on airplanes. However, they are very popular in RV, marine and light-duty vehicles.

Lead-Acid Batteries

Lead-acid batteries were invented in the nineteenth century and remain the most popular battery type on the EnergySage marketplace. They have a high surge-to-weight ratio and can deliver a burst of power when required. Despite this advantage, they are less durable than nickel- and lithium-based systems and have one of the lowest energy densities. Nonetheless, they have a good service life and are cheap.

They are constructed with a series of alternating lead and lead dioxide plates and an electrolyte of sulfuric acid. The positive plates are called the anode and the negative ones the cathode. The electrolyte prevents short circuits between the plates, and during use electrons flow from the anode to the cathode converting the lead into solid lead sulfate. When a battery discharges, the lead sulfate is converted back to the anode and cathode. A new charge reverses the process and restores battery capacity.

Two variants of the lead-acid battery emerged driven by different market needs; small sealed lead acid (SLA), also known as gel cell, and large valve-regulated lead-acid (VRLA). Both have an electrolyte, but VRLA has a special design that prevents water depletion during stressful charging and discharging. To do so, it has added vents to release gases during pressure buildup. The other style suspends the electrolyte in an absorbed glass mat, a design similar to that used by nickel- and lithium-based systems.

Nickel-Cadmium Batteries

Nickel-cadmium batteries (NiCd) use nickel oxyhydroxide as the cathode and metallic cadmium as the anode with a potassium hydroxide electrolyte. They are widely used in portable applications such as power tools and emergency lighting. They are also used as backup battery for power systems and can be stored at almost any state of charge and under a wide range of temperature conditions.

During discharge, the cadmium metal in the anode reacts with hydroxide ions to form cadmium hydroxide and electrons, while the nickel oxide hydroxide in the cathode is reduced by these electrons to produce nickel hydroxide. The flow of these reactants produces a current that can supply a significant amount of energy to the load.

Nickel Cadmium Batteries have a relatively low internal resistance and can handle high charging/discharging rates without loss of performance. This makes them ideal for devices that require a burst of power and then remain operational for a portable lithium battery long time. Their cycle life is much higher than that of lead-acid batteries and about half that of lithium-ion batteries.

They can suffer from the memory effect, which reduces their capacity over time if they are not fully discharged before being recharged. They also contain toxic materials, particularly cadmium, which raises safety concerns in their production, usage, and disposal. Consequently, they are usually subject to strict environmental regulations and must be recycled properly.