The Evolution of Batteries
by Jon Lung
From the miniature battery in a pacemaker that keeps a heart beating, to the large “battery rooms” that act as standby power for computing equipment in data centers, these artifacts of electrochemical power untether us from wall outlets and long unwieldy cables. This is an overview of how the modern battery formed, and what the future of the battery has to look forward to.
Batteries Then and Now:
Invented in 1800 and named after its inventor Alessandro Volta, the Voltaic Pile was the first true battery capable of providing a stable current. Since then, the principle of how a battery works has remained largely the same. Simply put, a chemical reaction causes electrons to move from one electrode to another through a conductive medium and collects at one end of the battery; an imbalance which give the battery its charge. The largest physical change happened in 1887 when German scientist Karl Gassner developed an electrolyte paste to replace its previous liquid form allowing for batteries to be used in any orientation, reducing the need for maintenance and the risk of spillage. Though a majority of batteries used today are dry cell, wet cell batteries have survived and are used in applications such as car batteries.
Types of Batteries:
All batteries fall into two categories: primary (single use) and secondary (rechargeable). During the lifespan of a primary battery, the Anode (positive terminal) transfers electrons to the Cathode (negative terminal) due to an internal chemical reaction. Once this reaction is exhusted, the battery dies. In secondary batteries like Lithium-ion (used most commonly in electronics today), lead acid (car batteries) and nickel metal hydride, this chemical reaction can be reversed with the application of a current (which is what happens when you plug them in to be recharged). Adversely, primary batteries, typically zinc-carbon and alkaline, cannot reliably have their chemical reactions reversed.
Under the umbrella of these two categories, there lies a whole host of variations on the internal reactants. Some on the primary cell list are alkaline, which rely on zinc and manganese dioxide, metal-air cells, that use pure metals at the anode end such as aluminum, calcium, and potassium to react with ambient air, and lithium cells that use a lithium anode and various cathodes to produce a reaction.
From the secondary side, lithium-ion as the name suggests, uses lithium ions to move between the negative and positive electrodes. Nickel cadmium, nickel metal hydride and lithium ion polymer are among the more common types of rechargeable batteries.
A larger battery of the same voltage and same internal chemistry will have a longer lifespan. Think of it as replacing the gas tank in your car with a larger one, giving you a longer ride before having to fuel up.
Self-discharge in various cells also becomes an important factor. Primary batteries fair better in this area with a 8-20% discharge per year, while secondary batteries, for example nickel based, lose 10% within the first 24 hours, and continue to lose roughly 10% a month after. Chemically, the battery can succumb to parasitic reactions that consume active chemicals, decreasing efficiency. Cycle life is also a factor to consider in secondary batteries as the aging processes of repeatedly being charged reduces its capacity over time.
Standard Battery Sizes:
Inside the swirling mess of standard and non-standard batteries, the basic size falls within three families of shape: cylindrical, non-cylindrical, and button cell. Each size and shape has a different voltage and best case scenario for use. When developing a product, choosing a battery comes down to the following considerations:
- Looking at application and questions of size constraints
- Required use time between charges and/or replacement
- Consumer access to a product’s internal workings
- Importance of battery toxicity and other details that allow us to sort through the myriad of options
Attempts to Disrupt:
In the world of batteries there are four main factors to consider:
- Size: Imprint Energy are using their ZincPoly™ technology to screen print paper thin batteries, trying to create an alternative to lithium-ion batteries that don’t perform well when created extra slim.
- Cost: Alveo energy is harnessing the power of water and Prussian blue dye, containing iron and copper, to create incredibly inexpensive, but long lasting batteries.
- Charge Rate: Available for pre-order now is the Pronto: Fast-Charge battery pack that can store enough power in a 5-minute charge to charge a completely dead smartphone to 100%.
- Capacity: Prieto is also working on a battery that lasts five times longer than traditional Lithium-ion. They also claim a 5-minute recharge.
The Future of Batteries:
With developments currently focused on near-field power transferring techniques such as inductive charging found in technologies like RFID tags, smartcards, and pacemakers, an interesting leap for battery technology lies in far-field techniques. Known as “power beaming”, power is transmitted via electromagnetic radiation such as laser beams and has suggested applications like powering space elevators and drone aircrafts in-flight. The issue with this system is the potential harmful exposure of people to electromagnetic radiation.
There is also a push towards renewable battery technologies that look to nature to provide sustainable battery materials. Sustainable Alternative Lighting (SALt), uses seawater as the electrolytic fluid to power a lamp in order to eliminate the need for kerosene and traditional battery-powered lamps and candles in the Philippines, where most islands do not have access to electricity. Biological batteries use bacteria in soil, or sometimes sugar, to react with the anode, but are far from being able to give power significantly.
No matter where we source our energy from in the future — be it fossil fuels or green energy — we’ll need batteries with enough capacity to store it all. Currently, companies like Sakti are developing solid state batteries that use solid electrodes and electrolytes. These alternatives offer extremely low internal resistance, which translates to higher energy density — a.k.a. longer battery life.
As humanity’s ever-growing mastery over the sciences continues to forge ahead, there will always be developments in making things smaller, cheaper, longer lasting, and faster working. Its important for us here at Tomorrow Lab to keep up with the swift-moving current of the tech world in order to create relevant, long lasting products. In terms of batteries, perhaps one day the constant need to recharge will be pushed into the background of our consciousness with incredible near-everlasting power sources.