When I was young, Santa gave me a present that came without batteries. In the 60’s, finding an open store on Christmas day was rare. Fortunately, my dad found a Walgreens open and saved the day. When batteries are working, they are great. When a flashlight in a kitchen drawer is dead in a blackout, swear words ensue.
We’ve come a long way in battery technologies, but it has come with more safety concerns due to lithium cells.
A Brief History
In the 60’s the main battery type was a carbon-zinc cell. They held their charge but tended to leak.
In the 70’s alkaline became prevalent. They were also able to maintain their charge and had about 3 times the energy density of carbon-zinc. Devices also came rechargeable using nickel-cadmium batteries. Ni-Cad batteries were OK, but they had an undesirable memory effect when recharging them from being partially discharged, which caused them to not ever fully recharge. They also self-discharged about 20% per month. Leaving Ni-Cad batteries on a 1970s charger for a long time to overcome the self-discharge problem ruined the batteries. Cadmium is a toxic metal, so recycling it is imperative.
In the 90’s nickel metal hydride appeared and was rechargeable. The chemistry produced 1.55V, close enough to substitute for alkaline. All those alkaline batteries that were thrown away after being in Walkman now could be replaced by NiMH rechargeables. NiMH could be recharged about 1,000 times and was much better than Ni-Cad.
Today’s Technology
Today, lithium batteries rule for the highest power density. There are many chemistries of lithium batteries. The most common cell chemistries are lithium cobalt oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese cobalt oxide (NMC), and lithium iron phosphate (LFP). Indesign is using LFP for a project because it is safer than other chemistries, but it has a lower power density compared to the other chemistries.
Lithium batteries have been in the news due to thermal runaway and fires occurring. The liquid electrolyte is flammable, combustible, corrosive, and toxic. Computers, hoverboards, e-cigarettes, EVs, and other devices have had problems with fires from lithium batteries. The hoverboard issue caused UL to issue a new standard of safety. The boards were previously unregulated. E-cigarettes on planes are also now regulated.
Current research is working towards making solid-state lithium batteries instead of using liquid electrolytes. Solid-state batteries should be safer with even higher energy densities. Many companies have prototypes but are finding scaling to production difficult. Toyota is working with Idemitsu Kosan, another Japanese company, to develop the solid-state battery. They expect it to be commercialized by 2027 or 2028. If solid-state batteries do become successful, the range anxiety of electric cars should be eliminated.
About Indesign, LLC
Indesign, LLC is a multi-discipline engineering design firm that provides full turnkey electronic product development to allow clients to get their new product ideas into the market quickly. We provide specific design engineering services and expertise in electrical design, RF/wireless design, embedded software design, and mechanical design. Our broad experience in electronic product development is evident in the wide variety of products we have designed for our clients. To learn more about us and our services, contact us at (317) 377-5450 today!