Take a moment and realize how essential batteries are.
Most devices and gadgets that have become inseparable in your daily life would turn lifeless without batteries.
If processor and storage form the brain of your devices, the battery is the heart that pumps energy through your device’s veins.
Yet if you are not an engineer or science major, there is a good chance you know very little about this crucial component.
So, let’s change that a little bit.
While the type of batteries and their use cases vary, this article discusses common questions about the most popular one.
Do lithium-ion batteries have memory?
Lithium Ion batteries are high-energy density batteries widely used in many commercial appliances. Lithium Ion batteries do not have a memory effect, meaning they don’t lose their efficiency if subjected to recharge cycles on partial discharge.
If you find this statement challenging, don’t worry; I will make it simple as we progress.
When understanding a concept, it is essential to cover all basics. In the subsequent sections, we will cover all basics and arrive at a comprehensive understanding.
Therefore, I urge you to read the article till the very end.
What is Memory Effect in Batteries?
So, why is the term memory used with batteries?
In everyday language, memory is generally associated with one’s capacity to recall something.
And if devices like your smartphone are concerned, memory means its RAM or storage capacity.
In the context of batteries, the memory effect is the ability of a battery to remember its usage patterns.
Recharging a battery repeatedly after it is only partially discharged, it slowly loses its usable capacity and outputs reduced working voltage.
The memory effect is also known as the lazy battery effect.
It causes the battery to hold less charge and lose its maximum energy capacity.
The battery seems to “remember” the smaller charge capacity and thus the name.
Memory effect is most profound in nickel-cadmium and nickel-metal hydride batteries.
A battery with a memory effect will discharge at a lower capacity. Any device attached to the battery will show a lower energy estimate than the battery can deliver.
Do Lithium Ion Batteries Degrade over Time?
Now that we know Li-ion batteries don’t exhibit a memory effect, is it true that Lithium-Ion batteries still degrade over time?
Yes, Li-Ion batteries do degrade with time. All components, including batteries, are subject to time-bound wear and tear.
You might have observed that with time your laptops and smartphones require more frequent charging than when you first got them.
So, to understand how and why Li-Ion batteries degrade, let me give you a brief overview of how LiBs operate.
As indicated by the name, LiBs operate because of the movement of Lithium ions.
The Lithium ions move from one electrode(cathode and anode) to the other through an electrolyte during charge and discharge cycles.
The cathode is created out of a layer of lithium-rich material. On the other hand, the anode is made from graphite layers into which the lithium ions can be pushed and trapped during charging.
The lithium ions move from one electrode to the other via a conductive medium known as the electrolyte.
When charging, the energy from the outlet pushes lithium ions from the cathode to the anode via the electrolyte.
The device uses the potential energy generated during this transfer to function.
During usage, the trapped Li-ions in the graphite anode move back to the cathode, and the electrons released during the transition power the device.
Now you see that battery isn’t just a static part of your device. There is continuous development and release of energy within LiBs.
So, your battery’s performance won’t remain the same forever.
Going just a little deep, here are some other reasons that cause the degradation of a lithium-ion battery.
- With time and usage, the electrodes go through mechanical degradation. These days manufacturers use suitable electrolyte additives and careful cell design to minimize this, but it is just something that happens over the long run.
- Solid Electrolyte Interface, or SEI, causes capacity loss in almost all graphite-based lithium-ion batteries. The loss happens because of the formation of a barrier that obstructs the interaction with graphite. Using proper electrolytes can reduce this internal resistance.
- Capacity loss can also happen because of electrolytic oxidation at the cathode. High voltage and high temperature is the main contributor to electrolytic oxidation.
- Lithium plating on anode due to high charging rates is also one significant cause behind capacity loss in LiBs.
Tips to Improve Lithium Ion Battery Life
Now that we know the core technical reasons behind the degradation of LiBs, it’s only logical to discuss actionable steps that help prevent that.
Here are some tips you, as a user, can follow to ensure that your battery lasts longer.
- Never keep a fully charged battery at an elevated temperature for an extended period.
Temperature-based degradation is more widespread in automobile lithium-ion batteries, but it also applies to consumer devices.
At elevated temperatures, the electrodes and electrolytes do not perform optimally.
If the electrodes and electrolytes aren’t in their optimal shape, a fair exchange of lithium ions will not take place.
If this continues for an extended period, the battery life decreases.
- Try not to charge over 80% and discharge lower than 20%
Lithium-ion batteries hate getting too charged or even too discharged.
Both extremely high and low “states of charge” put a lot of internal stress on batteries. Charge the battery until 80% of the maximum charge instead of 100%.
Manufacturers like Samsung and LG suggest recharging the battery when it is at 20% state of charge.
Outside the 80-20 range, the internal stresses cause battery degradation and capacity loss.
- Maintain an Optimal Charge Rate
It’s slightly less convenient, but lithium-ion batteries last longer when the charging process is slow.
High current flow via a fast charging process will heat and degrade the battery fast.
The same applies to very high discharge rates as well.
- Lower Charge Voltages Prolong a Lithium Ion Battery Life
Using lower charge voltages on a Lithium Ion battery will prolong its life. Using low-charge voltage is already a practice in electric vehicles and satellites.
And we are beginning to see the same provision applied to consumer devices like laptops.
Li-ion batteries charge to a maximum of 4.20V/cell. LiBs tend to last long if a reduction in peak charge voltage of 0.10V/cell is applied.
For instance, a LiB charged to 4.20V/cell is good for 300-500 cycles. Reducing the voltage by 0.10V/cell and charging it to 4.10V/cell provides 600-1000 cycles.
Therefore, if you want the battery to last longer, try reducing the peak charge voltage.
- Control Charging and DOD
How you charge your battery will determine how long your LiB will last.
At what temperature are you charging the battery, how fast are you charging the battery, and till what state of charge will determine how long the battery will last.
DoD, or Depth of Discharge, is another critical parameter that will dictate battery life.
Conclusion
This article has been a little more technical than what you guys are used to at Yantraas.
But I couldn’t help it because the topic of whether lithium-ion batteries have memory did deserve to go a bit deep.
Yet, I have tried to keep the language suitable for both beginners and experienced tech people.
Let me quickly summarize everything we have learned today.
- Unlike Nickel Cadmium and Nickel Metal Hydride batteries, Lithium Ion batteries are immune to the memory effect.
- Just because Li-Ion batteries don’t exhibit a memory effect doesn’t mean they don’t degrade with time.
- LiBs degrade due to time wear, SEI, electrolytic oxidation, and lithium plating.
- To prolong battery life, use optimal charge rate, don’t use the battery at extreme temperatures, recharge between 20-80%, maintain optimal charge rate, and use low charge voltage.
I hope you enjoyed reading the article as much as I enjoyed writing it.
If you have any other questions regarding Lithium Ion batteries, just shoot them in the comments section below.
Remember to join my badass group of tech enthusiasts.
Take care of yourselves, and I will see you at the next one!
