Batteries standing for a year +

[cgs]

Hello ALL.
Hope you guys are well, been a while.

I smoked my last cigarette (again) this morning and got the old vape gear out.
I have 18650s and 21700s, (sony / samsung) that have been sitting ± a year and a half in a container in a cupboard.

What do you think, yay or nay? Safe?
I prefer to use my mechanicals so just thought I'd double check with some smarter minds.

Shot.
Live long and prosper.

 

[Kuhlkatz]

If you have a multimeter or voltmeter, check to see if they are at least still above 2.5 volt. The clever people reckon that electrodes start degrading / dissolving when Lithium Ion batteries drop below 2 volt, typically when stored for long periods or over-discharged.
Also see voltage limits section at https://en.wikipedia.org/wiki/Lithium-ion_battery.

If no voltmeter is available, see if you have a facility on the Mod that will show you the actual voltage reading - before you attach an atty.
Mods typically will not fire when the battery is below 3.2 or 3.3 v.

If you have an external charger, pop them in there first to ensure that they are fully charged again before re-use.

 

[Stranger]

As above, very good advice.

If the batteries were stored at over 50% charged they will probably be as good as when you last used them.

Congrats on the last ciggie

 

[Intuthu Kagesi]

You've got some good advice above, and you could also check out;
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

It seems that they respond best to storage at room temperature, with a 40 - 50% charge as apposed fully charged or flat, and are apparently good for some 10 years plus with minimum degradation at this float.

 

[Timwis]

As above, very good advice.

If the batteries were stored at over 50% charged they will probably be as good as when you last used them.

Congrats on the last ciggie

Agree and that's the main reason new batteries are shipped with at least 50% charge to give them long shelf life!!!

 

[cgs]

If you have a multimeter or voltmeter....

I have a new one on the way.
For now I'm putting the fresh charged batts in a sigelei; it's got 2 V readings - pretty handy.

If you have an external charger...

Done. Will use the regulated for a charge cycle just to be sure.

Congrats on the last ciggie ...

TY very much

If the batteries were stored at over 50%...

It seems that they respond best to storage at room temperature...

Exactly what I did.
Thinking about older laptop batteries. They take some abuse and I've had laptops that never had a battery problem.

Thanks very much for taking the time to respond guys and for the links. Much appreciated.
I have 12 x 18650 and was looking at all of them and it would have stung to get new ones. Waste not, want not.

 

[Kuhlkatz]

Thanks very much for taking the time to respond guys and for the links. Much appreciated.
I have 12 x 18650 and was looking at all of them and it would have stung to get new ones. Waste not, want not.

Glad we could help, and thanks for the feedback. People around here are very liberal in parting with any form of advice.
You did mention mechs, so it's a good thing you had a regulated mod available to check with.

Good luck with try #2 to keep off the stinkies. Don't bash yourself over it. No-one here is going to be judgemental on that front either.
It's very easy to go back to the easiest method of getting your nic fix. A lot of people actually quit vaping not because vaping does not work, but rather due to the fact that it involves a bit more 'admin' for them to keep at it. It's just so simple to open a pack of smokes and light up, in comparison.

 

[RainstormZA]

I have a battery that sat for a year as my single battery mod needs repairing. I tried using it after a year, it’s a no go and even my battery charger says it’s bad so it’s in the battery bin

 

[Sweets]

I have x4 30Ts in my cycle with a mech at 0.09 - 0.12 with different coils for more than 3 years. These numbers will indicate consistent hard use and i can now feel they are starting to get weak... Its almost been 4 years with the 4 batteries.

Just my personal experience with samsung. I believe yours will be fine. If it was stored above 50% or 3.2v you should be ait. The brand does contribute to longevity. If it was ijoy or some other pavement brand i wouldn't even risk it.

 

[KAPOW]

When lithium-ion (Li-ion) cells are left for a long time and become over-discharged (typically below 2.0–2.5V, depending on the cell's chemistry), several internal chemical and physical changes occur that can degrade the cell's performance, safety, and longevity. Here's a detailed breakdown of what happens to the internal chemistry:

### 1. **Electrolyte Decomposition**
- **What Happens**: The electrolyte, typically a lithium salt (e.g., LiPF₆) dissolved in organic solvents (e.g., ethylene carbonate, dimethyl carbonate), is unstable at low voltages. Over-discharge causes the electrolyte to decompose, forming gases (e.g., CO₂, CO, or hydrocarbons) and solid byproducts.
- **Impact**:
- Gas generation increases internal pressure, potentially causing swelling or leakage.
- Decomposition reduces the electrolyte's ability to facilitate ion transport, leading to capacity loss.
- Byproducts may deposit on electrodes, increasing internal resistance.

### 2. **Anode Degradation (Copper Dissolution)**
- **What Happens**: In over-discharged cells, the anode (typically graphite) potential rises significantly. If the cell voltage drops low enough (e.g., <1V), the copper current collector on the anode side begins to oxidize and dissolve into the electrolyte as Cu²⁺ ions.
- **Impact**:
- Dissolved copper can redeposit on the anode or cathode during recharging, forming metallic dendrites that may cause internal short circuits, posing a safety hazard.
- Loss of copper compromises the anode's structural integrity, reducing capacity and increasing resistance.
- Copper contamination in the electrolyte further degrades cell performance.

### 3. **Cathode Degradation**
- **What Happens**: The cathode (e.g., lithium cobalt oxide, lithium iron phosphate, or NMC) becomes overly lithiated during over-discharge as lithium ions are forced back into it. This can cause structural instability in the cathode material.
- **Impact**:
- Phase changes or crystal structure collapse in the cathode material reduce its ability to store lithium, leading to permanent capacity loss.
- Some cathode materials (e.g., LiCoO₂) may release oxygen or decompose, increasing the risk of thermal runaway if recharged improperly.
- Transition metal dissolution (e.g., cobalt, nickel, or manganese) can occur, contaminating the electrolyte and further degrading performance.

### 4. **Solid Electrolyte Interphase (SEI) Breakdown**
- **What Happens**: The SEI layer, a protective film on the anode formed during initial cycles, is critical for preventing unwanted reactions between the anode and electrolyte. During over-discharge, the SEI layer can partially dissolve or become unstable due to the high anode potential.
- **Impact**:
- SEI breakdown exposes the anode to the electrolyte, triggering further side reactions that consume lithium and electrolyte, reducing capacity.
- Reformation of the SEI during recharging consumes additional lithium, contributing to irreversible capacity loss.
- A compromised SEI increases the risk of lithium plating during recharge, which can cause dendrites and short circuits.

### 5. **Lithium Loss and Plating**
- **What Happens**: Over-discharge can cause irreversible lithium loss as lithium ions become trapped in the anode or cathode or are consumed in side reactions. If the cell is recharged improperly, lithium may plate as metallic lithium on the anode instead of intercalating into the graphite.
- **Impact**:
- Lithium loss directly reduces the cell's capacity.
- Lithium plating creates dendrites, increasing the risk of internal shorts, which can lead to thermal runaway, fire, or explosion.
- Plating also increases internal resistance, reducing efficiency.

### 6. **Gas Generation and Pressure Buildup**
- **What Happens**: Decomposition reactions (electrolyte breakdown, SEI dissolution, or cathode instability) produce gases such as hydrogen, CO₂, and methane.
- **Impact**:
- Gas buildup increases internal pressure, potentially causing the cell to swell, leak, or rupture.
- In extreme cases, a ruptured cell can release flammable or toxic gases, posing safety risks.

### 7. **Self-Discharge Acceleration**
- **What Happens**: Over-discharged cells often experience accelerated self-discharge due to increased side reactions and compromised electrode stability.
- **Impact**:
- The cell may discharge further, exacerbating chemical degradation.
- Prolonged storage in an over-discharged state worsens the damage, potentially rendering the cell unusable.

### Factors Influencing Severity
- **Depth of Discharge**: Cells discharged below 1V experience more severe copper dissolution and electrolyte decomposition.
- **Duration**: The longer the cell remains over-discharged, the more extensive the chemical degradation.
- **Temperature**: High temperatures accelerate side reactions, while low temperatures may slow them but can still cause irreversible damage.
- **Cell Chemistry**: Different cathode materials (e.g., LFP, NMC, LCO) and electrolyte compositions react differently to over-discharge.
- **Age and Cycle History**: Older cells or those with many cycles are more susceptible to damage due to pre-existing degradation.

### Practical Outcomes
- **Capacity Loss**: Over-discharged cells often lose significant capacity due to lithium loss, electrode degradation, and increased resistance.
- **Reduced Lifespan**: Even if recharged, the cell's cycle life is shortened due to compromised internal chemistry.
- **Safety Risks**: Over-discharged cells are prone to short circuits, dendrite formation, and thermal runaway, especially if recharged improperly.
- **Non-Functional State**: In extreme cases, the cell may become completely unusable, failing to hold a charge or exhibiting dangerously high internal resistance.

### Safety and Handling
- **Do Not Recharge Blindly**: Over-discharged cells should be tested with a multimeter. If the voltage is below the manufacturer's safe threshold (e.g., 2.0V), recharging without professional equipment risks fire or explosion.
- **Inspect for Damage**: Swelling, leakage, or a strong odor indicates severe degradation. Do not attempt to use or recharge such cells.
- **Proper Disposal**: Damaged or over-discharged cells should be disposed of at a recycling or hazardous waste facility.
- **Storage Practices**: To prevent over-discharge, store Li-ion cells at 40–60% charge in a cool, dry environment, and check voltage periodically (every 3–6 months).

In summary, over-discharge of Li-ion cells triggers a cascade of chemical reactions—electrolyte decomposition, copper dissolution, SEI breakdown, and electrode degradation—that reduce capacity, shorten lifespan, and increase safety risks. Proper storage and handling are critical to minimizing these effects.