Causes, Prevention, and Safety Handling Guide for LiFePO4 Battery Swelling

Have you recently noticed swelling or bulging in your LiFePO4 battery cells? Battery swelling is a common issue that many DIY enthusiasts and LiFePO4 battery users might encounter. In this article, we analyze the main causes of battery swelling, preventive measures to take, and how to handle it safely.

Main Causes of LiFePO4 Battery Swelling

Manufacturing Defects in LiFePO4 Batteries

1. Material Issues:

Materials used in LiFePO4 battery manufacturing, such as electrode materials and electrolytes, may have quality issues. Non-compliant or unstable materials can lead to swelling in LiFePO4 batteries during use.

2. Process Issues:

Defects in the manufacturing process, such as improper sealing or unreasonable internal structure design, can also cause swelling in LiFePO4 batteries.

Improper Use of LiFePO4 Batteries

1. Overcharging or Overdischarging:

Charging and discharging processes should remain within appropriate limits. Overcharging or overdischarging can increase internal pressure in LiFePO4 batteries, causing them to swell.

2. Using Poor-Quality Chargers:

Poor-quality chargers may not accurately control charging voltage and current, leading to overcharging and swelling in LiFePO4 batteries.

3. Charging in High-Temperature Environments:

Charging in high temperatures accelerates chemical reactions within the battery, producing excessive heat. Poor heat dissipation increases internal pressure, causing battery swelling.

LiFePO4 Battery Aging

1. Performance Degradation:

With prolonged use, LiFePO4 battery performance gradually declines, increasing internal resistance. This may cause heating and pressure build-up, leading to swelling.

2. Internal Short Circuit:

An internal short circuit can cause the battery temperature to rise rapidly, generating gases and leading to swelling or even explosion.

Other Factors

1. Poor Sealing of LiFePO4 Battery:

When the battery seal is poor, external air or moisture may enter, reacting with materials to produce gases. These gases accumulate inside, increasing pressure and causing swelling.

2. Damaged Safety Valve:

Some LiFePO4 batteries are designed with a safety valve to release pressure when internal pressure is too high. If the safety valve is damaged or blocked, it cannot release pressure, leading to swelling.

Preventive Measures for LiFePO4 Battery Swelling

• Use chargers and LiFePO4 batteries from reputable manufacturers.
• Avoid charging in high temperatures; choose a cool, well-ventilated place for charging.
• Control charging time to avoid prolonged charging and overdischarging.
• Regularly check battery condition; replace if swelling, leakage, or other issues are detected.

Can a Swollen LiFePO4 Battery Be Repaired?

The answer is: Repairing is not recommended, mainly for the following reasons:

1. Irreversible Nature of Swollen LiFePO4 Batteries

Swelling typically results from chemical reactions or physical changes that damage the internal structure and produce gas, causing the casing to expand. This change is usually irreversible, meaning performance and safety have been significantly compromised.

2. Safety Hazards

A swollen LiFePO4 battery poses a considerable safety risk. High internal pressure may cause rupture, leading to liquid leakage and gas release, which can be corrosive or flammable, posing harm to equipment and personnel. Swollen batteries also increase the risk of short circuits, fires, or even explosions.

3. Difficulty and Risk of Repair

Repairing swollen LiFePO4 batteries requires specialized skills and equipment, which most users lack. Even methods like venting gas or refrigeration may not work and could introduce more risks. Improper handling during repair can further damage the battery.

4. Unreliable Performance After Repair

Even if successfully repaired, performance may still be compromised due to altered internal structure and chemistry, causing reduced capacity and lifespan. From a time and cost perspective, replacing the battery is more practical than attempting repair.

Is It Safe to Continue Using a Swollen LiFePO4 Battery?

A swollen LiFePO4 battery indicates changes such as increased internal pressure or deformed electrodes, which can affect both performance and safety. Therefore, it is generally not recommended to continue using a swollen battery.

Specific risks include:

Short Circuit and Explosion Risk:

The internal structure may be damaged, leading to potential short circuits that could cause fires or explosions, especially in high-temperature or improper use conditions.

Damage to Other Equipment:

Swollen batteries may rupture due to excessive internal pressure, with leaking liquid potentially causing corrosion or damage to other equipment components.

Performance Degradation:

Parameters like capacity and voltage may become abnormal, leading to reduced performance, such as slower speeds or shorter runtime.

However, if swelling is minor and capacity still meets requirements, some users may choose to continue using it. In such cases, close monitoring is essential, along with checking charger parameters to prevent further overcharging.

We hope this simplified guide helps LFP beginners understand battery swelling causes and risks. If you have any additional questions, let us know! Safety should always be a priority when using LiFePO4 batteries.