Causes of e-cigarette battery bulging: overcharging, high temperature environment and identification of inferior batteries

Overcharging: Over 40% of bulging cases are caused by "overcharging."

"Lithium-ion batteries have strict charge and discharge thresholds. Once the safe range is exceeded, the internal chemical reactions become uncontrolled." A Sanlei laboratory engineer explained that the rated voltage of current mainstream e-cigarette batteries is mostly 3.7V-4.2V. Using a non-genuine charger or charging for more than 8 hours can easily cause the battery to receive excessive current.

A recent report released by the laboratory showed that of 200 cases of e-cigarette battery bulging collected on the market, 82 were directly related to overcharging, accounting for over 40%. "Non-genuine chargers may have voltage instability issues. For example, directly inputting 5V into a battery rated for 4.2V can accelerate the decomposition of electrolytes and produce gas." The engineer gave the example of a consumer who used a mobile phone fast charger to charge an e-cigarette. After three hours, the battery showed noticeable bulging. Upon disassembly, electrolyte leakage was discovered.

What’s more noteworthy is that even if the battery does not swell immediately, overcharging can cause irreversible damage. "After an overcharge of more than 8 hours, the battery cycle life will be shortened by more than 50%, and the risk of bulging during subsequent use will be greatly increased." The engineer added. High Temperature Environment: The probability of bulging increases threefold at 60°C.

"E-cigarette batteries are heat-sensitive components, and high temperatures can act as a catalyst for bulging." A quality control manager for a well-known e-cigarette brand explained that the optimal operating temperature for batteries is 0°C-45°C. When the ambient temperature exceeds this range, the internal electrode material ages three to five times faster.

Sanlei once conducted a set of experiments: placing electronic cigarettes in 25℃, 45℃, and 60℃ environments, and observing the battery status after 2 hours. The results showed that there was no bulging at 25°C, 5% of the batteries had slight bulging at 45°C, and the bulging probability soared to 30% at 60°C, which is three times that at room temperature. "In the summer, the temperature inside a car often exceeds 60°C. If you leave an e-cigarette in the car exposed to the sun, the risk is extremely high." Sanlei reminds e-cigarette consumers that they should also be vigilant against local overheating caused by equipment failure. For example, high battery temperature caused by a short circuit in the atomizer core may cause bulging within 10 minutes.

How can you identify inferior batteries? Sanlei's engineers offer four practical tips:

First, check the labeling. High-quality batteries will have the brand, model, rated voltage, capacity, and production date clearly marked on the surface, with firm, durable printing that won't peel off. Low-quality batteries often have blurred or incomplete labeling, even with typos, and some may lack any brand information at all. Secondly, check the texture. High-quality battery shells are mostly made of aluminum alloy or composite materials, which feel smooth, have no burrs on the edges, and do not deform when pressed. Low-quality batteries are mostly made of cheap plastic or thin iron sheets, which feel rough, will dent when pressed lightly, and have signs of leakage at some seams. Secondly, measure the weight. High-quality batteries with the same capacity will be 5%-10% heavier than low-quality batteries due to the high purity of the materials. When shaking the batteries, high-quality batteries will not make any loose noises, while low-quality batteries may make a "clattering" sound due to the loose internal structure.

Finally, verify the battery's certification. Genuine batteries will be certified by 3C, CE, and RoHS, and will include a test report within the packaging. If the seller cannot provide these certification documents, proceed with caution.

Don't panic if your battery is bulging: Here's how to handle it more safely.

What should you do if you discover your battery is bulging? Engineers emphasize that the first rule is to "stop using" and avoid further charging or discharging. Wear gloves when handling the battery and place it in a fireproof container such as a ceramic bowl. Never crush, puncture, or place it in fire to prevent fire or explosion.

"Bulging batteries are hazardous waste and should not be discarded carelessly." Therefore, it is recommended that you contact the brand's after-sales service for professional recycling. Some cities have battery recycling points, and you can also hand them in at these locations.

Industry experts call on consumers to give priority to regular brand e-cigarettes and original accessories, avoid overcharging and stay away from high-temperature environments during daily use.