Sodium chemistry has begun making inroads into lithium-ion’s market, because the two designs are structurally similar. However, research on Science Direct cautions against sodium-ion battery overcharging, because this may threaten battery performance. We report on the relationship between overcharging and degradation in this short post.
Battery Management and Sodium-Ion Overcharging
It should not normally be possible to overcharge a sodium-ion battery significantly, if it has a functional battery management system on board. However, this error is still statistically feasible, and if it occurs, there may be battery damage.
Besides that, there is also the possibility of manufacturing errors leading to some individual cells having lower resistance, the researchers note. In this case, those inferior cells may pass their cut-off points and continue charging.
Sodium-ion battery overcharging is not unique to sodium-ion chemistry. There are rogue manufacturers in every sector of the battery industry. Our best defence against this, as consumers, it to purchase batteries from suppliers we trust.
What If Sodium-Ion Chemistry Charges for Too Long?
If we over-charge sodium chemistry for too long, then complex electrochemical reactions and physical changes may occur inside the battery. Dendrites may pierce the separator, the researchers warn, whereafter the electrolyte may release flammable gas.
The research team experimented with different levels of sodium-ion overcharging, to determine the threshold at which thermal runaway becomes a risk. Then they experimented within that limit, and developed the risk profile we summarise below:
- There was little battery degradation before the state of charge reached 120%.
- But at 130%, the electrode showed significant irreversible loss of sodium inventory.
- While beyond 140% of normal charge, there was ‘significant capacity degradation ‘.
This study suggests that the sodium ion batteries used for this particular experiment incorporated a margin of error. However, we warn against attempting to replicate these trials, under any circumstances regardless of the temptation to do so.
More Information
Sodium-Ion Invading Lithium-Ion’s Market
Could Sodium-Ion Outwit Lithium-Ion Soon?
