Is it okay to keep a power bank in the trunk during summer?

[JoelAnn]

It is not advisable to keep a power bank in the trunk during summer. Here are specific details about items that should not be left in the car in summer: 1. Lighters: In hot summer, outdoor temperatures can reach around 35 degrees Celsius, not to mention the enclosed space inside a car, which can easily lead to explosions. 2. Power banks: When the car temperature is high, batteries left in a high-temperature environment for a long time can bulge or even explode. Therefore, car owners should avoid placing electronic product batteries such as mobile phone batteries and digital camera batteries on the top of the center console exposed to direct sunlight or on the storage shelf between the rear seats and the window.

[MacDelilah]

Never throw a power bank in the trunk during summer! I tried it once, and when I retrieved it, the entire casing had swollen. Parking lot test data: Under direct noon sunlight, trunk temperatures can soar above 70°C, far exceeding the safe threshold for lithium batteries. Lithium batteries are most vulnerable to high temperatures—at best causing permanent damage and capacity reduction, at worst leading to electrolyte leakage or even spontaneous combustion. Once on the highway, I smelled burning and discovered a power bank smoking in the luggage compartment—I panicked and quickly rolled down the window to toss it out. If you must store one, wrap it in a heat-insulating bag, ideally stashing it in the glove compartment, or carry a portable cooling box.

[NevaehLee]

As an electronics enthusiast, I've researched this issue. The hazards of storing power banks in high temperatures mainly manifest in three aspects: first, the polymer separator can deform above 60°C leading to short circuits; second, the electrolyte may evaporate and expand under heat causing bulging; third, overheating can cause protection board components to fail. A closed car cabin in summer functions like an oven - while the windshield can be tinted for cooling, the trunk has absolutely no heat dissipation pathways. Last year I disassembled a heat-damaged power bank and found crystallized electrodes inside. My current practice is: choose metal-shelled power banks for car use, regularly check for bulging, and slow-charge to reactivate any unit unused for over three months.

[MacOmar]

We in the freight industry deal with high temperatures year-round. Last week, a fellow driver's power bank exploded in the trunk—fortunately, the cargo was textiles and didn't catch fire. Honestly, a thermometer showed the trunk temperature exceeding 55°C after just two hours of parking in the open. Lithium batteries degrade twice as fast for every 10°C rise in temperature, and heat also accelerates internal chemical reactions. Here are some emergency tips: wrap the power bank in two layers of aluminum foil to reflect some heat, open the trunk for ventilation when parking in the shade, and place a bottle of ice water nearby. But the safest practice is to make it a habit to take it with you when you leave the vehicle—safety is no small matter.

[DiRyder]

Once when camping with my child, I found the power bank in the trunk was as hot as a hand warmer. Later, I learned from research that lithium batteries become unstable when the ambient temperature exceeds 45°C. Especially with off-brand power banks that cut corners on protective circuits, they can't cut off the current in time under high temperatures. Here's a simple test method: place a thermometer in the trunk for 2 hours, and if it exceeds 50°C, definitely don't store anything there. Now I've modified the spare tire well at the rear of my car, lining it with thermal insulation as a temporary storage compartment. Actually, using a sunshade to cover the trunk can also reduce the temperature by about 7-8 degrees, which is much better than direct exposure to the sun.

[LeNoah]

Just learned a painful lesson: my newly purchased 20,000mAh power bank was left in the car trunk for three weeks. When I needed it for a business trip, I found only 3,000mAh of usable capacity remained. The repair technician said high temperatures caused irreversible lithium-ion activity degradation. Three key summer vehicle heat dissipation tips: the dashboard area gets hotter than the trunk, black paint absorbs significantly more heat, and parked cars heat up three times faster than when moving. Now I always carry a mini power bank in my bag, keeping only certified manufacturer products in the cabin – safety-certified explosion-proof battery cells have better heat resistance.