Recently, the power bank industry has been in turmoil, with Anker Innovations recalling 710,000 pieces of power banks in China, 1.158 million pieces of power banks in the United States, and 490,000 pieces of Roma in China. According to multiple sources, the recall may be related to the battery cell supplier Amprius (Wuxi) Co., Ltd., the company's 3C certificate was suspended or revoked, and it also affected the 3C certification of many brands of mobile power supplies such as Greenlink Technology and Baseus Technology. Although the recall reflects the company's responsibility to consumers, it also exposes the loopholes in the management of brands and suppliers and the potential safety hazards in the industry. As a necessary "life-sustaining artifact" for going out, the product classification, cell quality, safety hazards and other knowledge of power bank are hidden in the doorway, and the next full strategy will reveal the hard-core knowledge that 99% people don't know, to help you buy lightning protection and charge safely.
1. Classification of power banks
1.1 Classification by cell type
The "heart" of power banks - the cell type, directly affects performance and safety. Currently, mainstream cells can be divided into two camps:
Among lithium-ion cells (cylindrical), 18650 batteries are considered "star players". With mature and stable technology and high cost performance, it has become the first choice for basic models of many brands; the advanced 21700 battery has gone a step further in terms of safety. It not only has more cycles of charge and discharge and a longer service life, but is also suitable for mid-to-high-end mobile power supplies, but the corresponding price is also higher.
Lithium polymer cells (soft packs) focus on "customization" and "flexibility". It breaks through the traditional shape restrictions and can create a thin and portable appearance. However, due to technology and material costs, its price is slightly higher than that of 18650 cells. Nowadays, big-name power banks that pursue extreme lightness and thinness mostly use lithium polymer cells; while high-end products that support TFT multi-functions and high-power output often use 21700 cells, taking into account both performance and quality.
1.2 Classification by charging method
Wired power bank: "Hard power" for multi-protocol fast charging
Equipped with USB-A and USB-C dual interfaces, it can be called an "all-round player" in charging scenarios. Among them, the USB-A interface covers a variety of fast charging protocols: the general charging mode is adapted to basic devices, QC fast charging (Qualcomm solution), FCP (Huawei fast charging) and Huawei 22.5W super fast charging, which can achieve efficient charging for Android devices; the USB-C interface is mainly based on the PD fast charging protocol, which is compatible with the high-power charging requirements of Apple, notebooks and other devices, and has stronger adaptability.
Wireless power bank: Get rid of the "free charging" experience of wires. The wireless power bank is based on the Qi wireless charging standard. It can be charged without plugging in a wire. Just place the device on the charging panel to automatically power it. The upgraded Qi2 magnetic wireless power bank also adds a magnetic suction function, which can fit the iPhone 12 and above models accurately, and the charging stability is stronger. It is very suitable for Apple users who pursue convenience.
Pitfall avoidance guide: If you are looking for charging efficiency, you can give priority to a power bank with its own cable - it not only retains the convenience of wireless charging, but also can achieve PD/super fast charging through the built-in cable. It is especially suitable for users who have dual needs of "fast charging + portability".
1.3 Classification by usage scenario
Daily commuting: It is recommended to choose a 5000-10000mAh power bank. They are small and light, and can be easily put into a backpack or pocket without any pressure. They can easily meet the power needs of the mobile phone 1-2 times, so that you don't have to worry about the power on the way to and from get off work.
Business trips and travel: 20000mAh is the golden capacity, which can not only achieve multiple full-charge endurance of devices, but also meet the carrying standards of public transportation such as aviation and high-speed rail. With the fast charging function, you can quickly recover blood during the waiting time, which is efficient and worry-free for business trips and travel.
Outdoor adventure: In the face of complex environments far away from power sources, large-capacity power banks above 30000mAh are the "endurance kings". Some products are also equipped with hard-core functions such as solar panels, SOS rescue lights, and LED emergency lighting. At critical moments, they become outdoor survival artifacts and continue to "extend life" for multiple devices.
Buying tips: For those who travel frequently, a 20,000mAh power bank is the best choice as it combines capacity and portability. For outdoor enthusiasts, it is recommended to choose a large-capacity + fast-charging model to ensure that multiple devices such as mobile phones, cameras, and drones are online 24/7.
1.4 Classification by charging and discharging speed
Slow charging power bank: The output power is 5V/2A. It takes 2-3 hours to fully charge a mobile phone. It is more suitable for charging low-power devices such as Bluetooth headsets and smart watches. Although the speed is slow, it is stable and safe, and is suitable for old models that do not support fast charging.
Ordinary fast charging power bank: It supports mainstream fast charging protocols such as PD and QC. The power is concentrated between 18W-45W, which can quickly "recharge" common devices such as mobile phones, tablets, and headphones. Taking the iPhone as an example, it can be charged to 50% in 30 minutes, which efficiently meets the needs of daily commuting and short-distance travel.
Laptop power bank: The power is more than 45W, designed for business people, and can be used for emergency fast charging of laptops. It is also compatible with tablets, mobile phones and other devices to achieve "one machine for multiple uses". On a business trip, it is not only a "life-saving straw" for laptops, but also a battery life guarantee for electronic devices in all scenarios.
Purchase suggestion: If you only need to charge your mobile phone or tablet, a fast charging model below 45W is sufficient; if you need to take into account the emergency of a laptop, it is recommended to choose a high-power power bank, which can easily cover the power needs of all types of devices and say goodbye to power anxiety.
2. Revealing the secrets of power bank batteries
In simple terms, the battery core is the "heart" of the mobile power bank, responsible for storing and releasing electrical energy. It is usually composed of a positive electrode, a negative electrode, an electrolyte and a separator. There are two types of battery cells commonly found in mobile power banks: cylindrical battery cells (such as 18650) and polymer lithium battery cells. Don't underestimate them, the performance differences are significant!
2.1 In the "core" world of power banks, the 18650 battery cell can be called a "classic hardcore player". When you disassemble an old mobile power bank, you can often see several cylindrical cells similar to AA batteries, which are 18650 cells. As an old-fashioned battery cell pioneered by Japanese companies, 18650 stands out with its mature technology and super high cost performance. The capacity of a single battery cell can reach 2000-3500mAh, which can not only meet daily power needs, but also become the first choice for entry-level products of many brands due to its stable technology and low production cost. It can be called the "evergreen tree" in the power bank industry.
Cold knowledge: The 18650 battery cell was actually originally designed for laptops, and later it was widely used in the field of mobile power supplies and electric vehicles. For example, Tesla uses it in large quantities. Its advantages are durability and strong stability, but its disadvantages are also obvious-it has a fixed shape and a large volume, so the mobile power supplies made with it are often not thin and light enough.
2.2 Unlike the "hard-core" image of 18650, polymer lithium battery cells (commonly known as "soft-pack batteries") have become the new favorite of portable devices with their "flexible body". It abandons the metal shell and uses aluminum-plastic film to wrap the battery cell. This structure allows it to completely get rid of shape restrictions - from ultra-thin card-shaped to special-shaped round, and even customized curved shapes for smart wearable devices, it can be easily achieved. With the design advantage of "no fixed shell", power banks equipped with polymer batteries can often be extremely light and thin, and the thickness can be compressed to less than 1cm, which can be put into a wallet or pocket without any burden. It can be called a master of balancing "lightness and performance".
Cold knowledge: Polymer lithium batteries were mostly designed for small smart devices such as mobile phones and Bluetooth headsets in the early days. Because of its flexible and customizable characteristics, it can adapt to the compact space of portable devices, providing key support for the lightness and thinness of small smart devices.
2.3 Why is the power bank marked with 10000mAh, but the actual battery life is reduced?
Have you ever encountered this situation: you bought a 10000mAh power bank, but it ran out of power after charging your phone a few times? Behind this is the "mathematical mystery" of battery capacity - nominal capacity ≠ actual available power.
The capacity marked on the battery cell (such as 10000mAh) is the theoretical value at 3.7V voltage, but when actually charging, the battery cell needs to be boosted to 5V output through the circuit, and energy will inevitably be lost in this process. Coupled with factors such as circuit board heating and component resistance, the power that can be delivered to the device is usually only 60%-70% of the nominal value. Taking 10000mAh as an example, the actual effective power that can be provided to the mobile phone is about 6000-7000mAh, which is the truth of your feeling of "reduced battery life".
Key points: Don't just look at the nominal capacity when purchasing. Pay attention to the "rated capacity" (usually marked on the power bank parameter page), which can more truly reflect the actual battery life.
Cold knowledge: In order to pursue high capacity, some low-priced mobile power supplies may use inferior battery cells or even recycle old battery cells. Not only is the capacity falsely marked, but the safety is also worrying. Therefore, don't just look at the numbers when purchasing. It is more reliable to recognize the brand and certification (such as 3C certification)!
2.4 The "lifespan secret" of battery cells
Battery cells also have a "lifespan", which is usually calculated by the number of charge and discharge cycles. High-quality 18650 and polymer battery cells can generally support 500-1000 cycles, but this is closely related to usage habits. For example, always letting the battery run out before charging, or using it in a high temperature environment, will accelerate the aging of the battery cell.
Cold knowledge: Did you know? The battery cell is most afraid of "over-discharge". If the mobile power bank is not used for a long time, the power may slowly run out to 0%, causing the battery cell to enter "deep sleep" or even completely damaged. Therefore, it is recommended to charge the idle mobile power bank once every 3 months!
3. Safety knowledge about power banks
3.1 Core safety hazards: potential risks of lithium batteries
Thermal runaway principle
When the lithium battery (18650 or polymer battery cell) of a power bank is overcharged, over-discharged, short-circuited or physically damaged, it will generate a lot of heat due to the uncontrolled internal chemical reaction, which may cause smoke, fire or even explosion, that is, "thermal runaway".
Risk scenarios: changes in air pressure during takeoff and landing of an aircraft (as described above); high temperature environment (such as exposure to the sun, confined space in a car); inferior products or knockoff batteries; overcharging (plugging in all night) or charging while using.
3.2 Use: 90% of accidents can be avoided through standardized operation
Charging safetyAvoid using non-original chargers (unstable current can easily damage the battery cell); stay away from flammable items such as bedding and clothing when charging, and keep ventilation; unplug the battery in time after it is fully charged, and avoid continuous charging for more than 8 hours.
Carrying and storage aviation restrictions: The capacity of a single power bank is ≤100Wh (about 27000mAh), which must be carried with you and is prohibited from being checked in; avoid putting it in the same pocket with metal objects such as keys and coins to prevent short circuits; when not in use for a long time, keep the power at 30%-50% and store it in a cool and dry place (temperature ≤25℃).
Abnormal handlingIf you find that the power bank is bulging, hot, has an odor, or makes an abnormal sound when charging, stop using it immediately, stay away from people and contact the brand after-sales service; in case of fire, cover the fire with a fire extinguisher or heavy clothing, and do not pour water (lithium batteries may react more rapidly when exposed to water).
3.3 Popular science to dispel rumors: These "common sense" are actually misunderstandings
"The larger the capacity, the more dangerous"?
The risk factor is related to the quality of the battery cell and the protection circuit. Large-capacity products from regular brands are safer.
"Power banks cannot be brought on planes"?
Products that meet the capacity requirements (≤100Wh) and are clearly marked can be carried on board, but are prohibited from being checked in.
"Will it explode while charging and using"?
The over-temperature protection of regular products will automatically cut off the power, but long-term charging and using will accelerate the aging of the battery cell. It is recommended to fully charge before use.
4. Conclusion
A small power bank contains a lot of knowledge. From the type of battery to the charging protocol, from scene adaptation to safety regulations, every detail may become the key to "stepping into the pit" - 99% of people may only look at the nominal capacity, but ignore the real meaning of the rated power; think "the cheaper the better", but don't know that the counterfeit battery has the risk of thermal runaway; use the power bank casually on the plane, but don't understand the safety hazards under the change of air pressure...
Choosing a power bank is never a simple question of "buy big and get small free": look for 3C certification and brand guarantee, match the capacity according to commuting/business trip/outdoor scenes, pay attention to the rated power instead of false parameters, and standardize charging and carrying habits, so that this "life-extending artifact" can truly become a safety backup.
Acey Intelligent specializes in providing one-stop solutions for semi-automatic/fully-automatic assembly lines of lithium battery packs used in ESS, UAV, E-Bike, E-Scooter, Power Tools, Two/Three Wheelers, Etc. The 3C type battery manufacturing machines can also be consulted with us. In Addition, we provide a complete set of battery pack assembly equipment, such as Cell Grading Machine, Battery Sorting Machine, Insulation Paper Sticking Machine, CCD tester, Manual/Automatic Spot Welding Machine, BMS Tester, Battery Comprehensive Tester and Battery Pack Test System, etc.
