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Along with lead acid, nickel-cadmium (NiCd) was one of the first batteries ever invented.
Dating back to the 1800s, lead acid and NiCad chemistry spent most of the 20th century competing over which was the most viable rechargeable battery type.
During that time, NiCd offered numerous advantages over lead acid. But with the advent of lithium-ion and, more recently, lithium iron phosphate (LFP/LiFePO4) battery technologies, NiCd has taken a back seat.
Except for very specific — primarily industrial — applications, LiFePO4 batteries are a much better option.
Read on to find out why…
What Is a NiCd Battery?
Nickel-cadmium batteries (NiCd/NiCad) are rechargeable batteries that were once commonly used in many electricity storage applications — for example, power tools, portable electronic devices, and solar batteries.
NiCd batteries have a long history — the first was invented in 1899 — and are in many ways superior to lead acid batteries, the most widely used alternative rechargeable battery for most of the 20th century.
In more recent years, the use of NiCd batteries has declined, primarily because of improved battery chemistries like nickel-metal-hydride, lithium-ion (Li-ion), and, more recently, lithium iron phosphate (LiFePO4/LFP) becoming affordable, widely available, and offering significantly better performance.
Additionally, the disposal of cadmium – a primary material used in NiCd batteries — has a devastating impact on the environment, the food chain, and human health. The European Union (EU) began banning the manufacture of NiCd batteries in 2006, and NiCd batteries can now only be used in limited applications under stringent manufacturing, disposal, and recycling regulations.
Advantages of a NiCd Battery
When lead acid batteries were the only alternative, nickel-cadmium batteries were seen to have numerous advantages. With today’s superior battery chemistry options, NiCd has very few advantages in comparison. However, they are still widely used in specific applications.
Here are the advantages of nickel-cadmium batteries over Li-ion and LiFePO4 that prevent their obsolescence in select (primarily commercial/industrial) use cases.
Uninterruptible Backup Power
NiCd batteries are sometimes preferred over newer technologies like Li-ion in applications where 100% reliable, uninterrupted electricity output is required in a wide range of environmental conditions. Examples include backup systems on airplanes, in hospitals, and in data centers where an uninterruptible power supply (UPS) is needed.
Even though the LiFePO4 batteries found in devices like EcoFlow’s portable power stations have an almost imperceptible switchover speed of less than 30 ms in a power outage, even that can damage sensitive electronic equipment like hard drives and desktop computers.
However, a <30ms Emergency Power System (EPS) auto-switch is perfectly acceptable in but a handful of applications.
Minimal Impact of Temperature on Performance
In applications where extreme fluctuations in temperature are expected — such as in airplane systems compartments and specific manufacturing processes — NiCd batteries offer highly reliable performance.
Extreme temperature changes — for example, from 14°F (-10°C) to 86°F (30°C) within hours or minutes — rarely occur in the natural environment but are common in industrial applications.
Additionally, the operating temperature range of NiCd batteries is exceptionally broad, averaging from −40°F (-40°C) to + 158°F (70 °C).
Depth of Discharge
NiCd batteries offer greater depth of discharge (DoD) than many other battery chemistries — especially lead acid. Higher DoD means NiCd batteries deliver a consistent electrical current and wattage even when almost fully discharged.
NiCd batteries can also tolerate deep discharges for extended periods without incurring damage. By contrast, many lead acid batteries will sustain permanent damage and suffer from reduced performance when discharged below 50% of their maximum storage capacity.
What Is a LiFePO4 (LFP) Battery?
Lithium iron phosphate (LiFePO4/LFP) batteries are a newer subset of Li-ion chemistry that offers numerous advantages over traditional lithium-ion batteries as well as NiCd and lead acid.
LiFePO4 batteries were invented in 1996, but the technology has vastly improved and seen much broader adoption in recent years. LFP batteries gained significant public attention when Tesla announced in late 2021 that it was switching to LiFePO4 chemistry for all its standard-range EVs.
As you can see from the chart above, the demand for LiFePO4 (LFP) batteries in the EV market has been explosive — a sign of its maturity as a technology that gives it many advantages over other battery chemistries.
Advantages of a LiFePO4 Battery
Electric vehicle manufacturers are by no means the only companies making the switch to LFP batteries. As the technology improves and prices plummet, industry-leading solar battery and off-grid power innovators like EcoFlow are also making the switch from NiCd and traditional Li-ion batteries to lithium iron phosphate (LFP).
Here are the major benefits of LiFePO4 batteries over NiCd — especially as related to solar and off-grid power solutions.
LiFePO4 batteries are less expensive to produce than NiCd, both when it comes to the cost of materials and the manufacturing process.
Unlike with lead acid, chronological time has minimal impact on the lifespan of Ni-CD and LiFePO4 batteries. Instead, it’s how often and how you use the battery (or batteries) in your portable power station or Power Kit that determines how long it will last before you notice a decline in performance.
That’s why understanding cycle life is crucial when researching which battery option is best for you. A “cycle” represents one full discharge and recharge of a battery. Cycle life is typically listed as a manufacturer’s specification indicating how many cycles your battery can provide before noticeably declining in performance.
Let’s make an “apples to apples” comparison that helps illustrate the vast superiority of LiFePO4 batteries to NiCd regarding cycle life…
The recently released DELTA 2 Max has already won a Red Dot Design Award and represents a massive upgrade on the original DELTA Max by virtually any metric.
For one, the DELTA 2 Max utilizes a LiFePo4 (LFP) battery. DELTA Max uses NiCd. Check out how this impacts cycle life alone.
- DELTA Max 2000 (Original) Cycle Life: 800 cycles to 80% capacity
- Delta 2 Max Cycle Life: 3000 cycles to 80+% capacity
That’s 275% more cycles at a 21% lower list price from the DELTA 2 Max with a LiFePO4 battery than DELTA Max with NiCD.
Note that diminished performance to 80% capacity doesn’t mean the PPS won’t work. You’ll just have to recharge it more often. DELTA 2 Max will last for 10+ years of regular use.
Faster Charge Times
LiFePO4 charges much faster than other battery chemistries — making them uniquely suited for EVs. Spend time at a charging station and more time on the road.
It’s also a massive advantage for solar power systems, where electricity generation potential is naturally limited by available peak sunlight hours in your location.
DELTA 2 Max can achieve a 0-80% charge of its 2,048Wh storage capacity LFP battery in a world-beating 43 minutes when combining 1000W solar input with AC (household) electricity. Or in 1.1 hours, using AC alone.
Wide Operating Temperature Range
Although LFP batteries can’t match NiCd for operating at extreme temperatures, they still have a more comprehensive operating temperature range than lead acid or traditional lithium-ion batteries.
Less Environmental Impact
The negative impact on human health and the environment of improper disposal of NiCd batteries — particularly the cadmium they contain — has already led to them being largely banned in the EU.
LiFeP04 batteries are considered far more eco-friendly. Dangerous heavy metals like lead or cadmium aren’t used in their production, and vast investments in lithium recycling mean that more lithium is being reused rather than mined from the Earth.
Additionally, LFP’s exceptionally long cycle life means that the batteries must be replaced less often — good for you as the consumer. And the environment.
More Humane Production and Supply Chain
Cobalt is essential for traditional lithium-ion batteries to function. Around 70% of the world’s cobalt is mined and processed in the Democratic Republic of Congo under brutal labour conditions.
DRC is one of the world’s poorest countries, and the skyrocketing demand for cobalt due to EV and other clean energy technologies hasn’t improved life for most of its people. Instead, women and children as young as six or seven work to meet global demand without reaping the benefits.
According to The Guardian, Apple, Google, Dell, Microsoft, and Tesla have even been sued “by Congolese families who say their children were killed or maimed while mining for cobalt.”
By opting for LiFeP04 batteries instead of Li-on, you’re making a choice that you can feel good about — both as a consumer and as someone who cares about human rights.
What Are the Differences Between NiCd and LFP Batteries?
Energy Density & Capacity
LiFePO4 batteries have more energy storage capacity by volume than NiCd batteries, which means you can store the same amount of electricity with less space.
Additionally, current LFP batteries have about double the energy density of NiCd, meaning they’re not only smaller than NiCd batteries of the same capacity, they’re lighter too.
Safety & Thermal Stability
LiFePO4 batteries are safer than both traditional Li-ion batteries and NiCd options. NiCd batteries are more likely to overheat, leading to diminished performance and even potential fire hazards.
Li-ion batteries are prone to thermal runaway, which can lead to a steep increase in internal battery temperature. Thermal runaway has been known to cause fires and even explosions.
By contrast, LFP batteries have greater thermal stability, making them considerably safer.
One of the most significant drawbacks of NiCd batteries is what’s known as the memory effect. When a NiCad battery is only partially discharged, it has a tendency to “remember” the level it was discharged to as its maximum storage capacity, significantly reducing subsequent battery life.
There are ways to potentially reverse the memory effect — such as fully discharging and recharging the battery and other reconditioning methods.
But this can be a considerable waste of your time and effort.
LiFePO4 batteries are not subject to the memory effect.
Cycle Life & Lifespan
As discussed previously, LiFePO4 batteries have a significantly longer cycle life than NiCd — often between 200 – 300%. More cycles mean a longer lifespan and a better return on investment.
It’s easier on your bank account and the planet because LFP batteries can be replaced far less frequently than their NiCd counterparts.
LiFePO4 batteries are less expensive to manufacture in terms of cost of materials and ease of production. Along with their many other benefits, decreased cost is one significant reason why so many EV manufacturers have embraced LFP battery chemistry in recent years.
However, depending on the application, a cheaper battery won’t always translate to a substantially lower price tag. With solar generators, for example, LiFePO4-powered models require additional/more complex components besides the battery to function optimally.
Frequently Asked Questions
For the vast majority of consumer applications — from RVs to power tools to off-grid power solutions — LFP batteries are far superior to NiCd batteries in many ways. LiFePO4 has NiCd beat on price, cycle life, charging speed, portability, and more. Unless you need a NiCd battery to start the engine of a commercial jet, LFP batteries have NiCd beat — hands down.
Back in the day, when there were only two consumer rechargeable battery technologies — lead acid and nickel cadmium — NiCd chemistry had some significant advantages.
But those days are long gone.
Except in applications where an uninterruptible power supply (UPS) is a necessity and in limited industrial use cases, NiCm is inferior to lithium iron phosphate (LiFePO4) in virtually every way.
At EcoFlow, LiFePO4 battery chemistry is at the heart of our off-grid power solutions like Power Kits and Smart Home Ecosystem.
Find out how to switch to clean, renewable energy with EcoFlow products today.