How to Remove Effects of Passivation and Restore Full Capacity in LiSOCl₂ Batteries

Understanding Passivation, Depassivation, and Recovery Procedure in LiSOCl₂ Batteries

LiSOCl₂ (lithium-thionyl chloride) batteries are widely valued for their high energy density, long service life, and broad temperature tolerance. However, these batteries are prone to passivation, a condition that can affect device functionality if not addressed properly. Below, we’ll cover what passivation is, why it happens, and how depassivation techniques restore battery performance. We’ll also discuss common challenges and practical solutions when using LiSOCl₂ batteries.

What is Passivation in LiSOCl₂ Batteries?

Benefits of Passivation:

• Extended shelf life: By limiting self-discharge, passivation prolongs battery life, making LiSOCl₂ batteries ideal for long-term, low-maintenance applications such as emergency power systems, military-grade equipment, and medical devices.
• Enhanced safety: The passivation layer reduces the likelihood of unwanted reactions between the anode and electrolyte, preventing risks of overheating, rupture, or, in rare cases, explosion.

Drawbacks of Passivation:

• Voltage delay: Passivation can cause a delay between battery activation and reaching the required voltage, potentially affecting correct device functionality in some devices.
• Voltage drop: During initial use, a sudden voltage drop may occur, causing unreliable performance or possible device malfunction.
• Reduced capacity: If passivation is not properly managed, the battery’s effective capacity can be compromised.

These effects are especially impactful for devices requiring immediate high current or precise voltage immediately after startup, such as GPS trackers, emergency location transmitters, and certain medical instruments.

What is Depassivation of LiSOCl₂ Batteries?  

Depassivation Techniques for LiSOCl₂ Batteries: A Step-by-Step Guide 

• Pulse load application: Apply short, high-current pulses to the battery. These brief pulses generate heat and energy to break down the LiCl passivation layer, bringing the battery back to the original operating condition.
• Gradual current increase: Instead of applying a sudden load, gradually increase the current into the battery. This gradual increase effectively dissolves the passivation layer while minimizing voltage drop.
• Rest period: In some cases, simply allowing the battery to rest briefly after the first connection can reduce the initial voltage delay, as the battery may partially recover on its own.

Recommendations to Mitigate Passivation Effects

• Avoid prolonged inactivity: Long periods of inactivity can intensify passivation. To prevent this, periodically activate the battery if it will be stored for extended durations.
• Store in optimal conditions: Keep LiSOCl₂ batteries in a cool, dry environment, avoiding extreme temperatures that could worsen passivation.
• Choose quality products: Not all LiSOCl₂ batteries are equal. Higher-quality batteries from reputable manufacturers handle passivation better and deliver more consistent performance.

CAUTION:

Depassivation requires technical skill and precision, it should be performed by qualified personnel with electrical expertise. Always use appropriate personal protective equipment and adhere to relevant local safety guidelines.
Depassivation may involve subjecting the battery cells to a brief load which reduces internal resistance temporarily and activates the battery. However, this process must be carried out with care in a controlled environment to avoid overheating or potential cell damage. Manufacturers may also recommend specific procedures, so it’s crucial to consult and follow the technical documentation provided with the battery.

A wide selection of LiSOCl₂ batteries is readily available on our website, ready to support your projects. If you are looking for different types of batteries, we are happy to supply them on order under favourable terms.