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"Life in Japan 2023" We found the manufacturer of the most powerful and safe mobile battery!

Nowadays, each person carries a mobile battery. While they are convenient, they also have an image of being dangerous due to accidents such as ignition. Today, we would like to explain about such mobile batteries and introduce recommended products.

Lithium-ion battery safety

With the revision of the notification dated February 1, 2008, mobile batteries are now subject to regulation under the Electrical Appliance and Material Safety Law. Since then, as proof that the notified business operator has fulfilled its obligations such as technical standards compliance stipulated in the law, the PSE mark, etc., can be displayed on the product. Currently, only electrical appliances and materials bearing the PSE mark and the required labeling can be sold.
Topics - Electrical Appliance and Material Safety Law (METI/Ministry of Economy, Trade and Industry)
Cautions on the use of lithium-ion batteries and chargers (announcement information)National Consumer Affairs Center

As a result, a certain degree of safety is now assured, but the reality is that some products are still being recalled.

Reason for Recall
Two incidents of lithium-ion battery cell ruptures were investigated, and as a result, the possibility of ignition was identified in some lots of products.

Product Safety (METI/Ministry of Economy, Trade and Industry)


Lithium-ion battery types

First, many people think that all mobile batteries are made of lithium-ion batteries, but this is not the case. There is a similarly used battery called a lithium polymer battery. Compared to lithium-ion batteries, they have the following characteristics, and if you do not care about thinness, lithium-ion batteries are safer as mobile batteries.

  • Low profile makes it suitable for power supplies for small devices
  • More stable than liquid lithium-ion batteries because the electrolyte is in gel form
  • The laminate outer skin is more vulnerable to external shocks than lithium-ion batteries, which use metal tubes.
  • Not suitable for use in high temperature, high humidity environments

Performance Comparison of Lithium Ion and Lithium Polymer Batteries


Next, we will discuss the classification of lithium-ion batteries. There are three types of lithium-ion batteries: cylindrical, rectangular, and laminated. The rectangular and laminated types have the property of expanding through repeated charge-discharge cycles.


The cylindrical type has the lowest cost and the highest capacity for the same volume. The external dimensions are also stable. However, when many cells are combined, gaps are created and density is reduced. Cylindrical cans are all made of steel.

■Square (iron cans, aluminum cans)

Square cans are available in steel or aluminum, and aluminum cans are becoming more common these days to reduce weight.


The thickness of the square type expands with charge/discharge cycles. After 100 cycles of charging and discharging, a 5 mm thick can can become 6 mm thick, so the design of the set should take this into account and allow for gaps.

■Laminate type

The laminated type uses laminated film in place of the square metal can, but the electrolyte inside is either the same liquid as that in the conventional metal can or a polymer-like material that encapsulates the electrolyte in a gel. In either case, the thickness of the laminate type increases with charge/discharge cycles as much as or more than the square type.
Ltd. for lithium-ion batteries - 4. Types of lithium-ion batteries


However, manufacturers also take expansion into account in their designs, and it is not necessary to replace the battery as soon as it expands. However, expansion can directly damage the lithium-ion battery when a shock is applied to the main body of the mobile battery. Therefore, among lithium-ion batteries, we recommend mobile batteries that use cylindrical batteries.

The reason why cylindrical lithium-ion batteries do not expand with gas is because they are designed to allow the generated gas itself to escape.

[ 4/6 ] Panasonic's "New Storage Battery Business Strategy" for Residential Applications | Electricity Storage/Energy Storage | Smart Grid Forum


However, the specifications and instruction manuals for each manufacturer's mobile batteries do not even say what type of battery they use. In many cases, it does not even say whether lithium-ion or lithium-polymer batteries are used. What we would like to refer to is the thickness. The most widely used cylindrical lithium-ion battery is the 18650 type, with a diameter of 18 mm and a total length of 65 mm. Therefore, we assume that mobile batteries that are less than 2 cm thick and 8 cm long, including the base and outer box, do not use cylindrical lithium-ion batteries.


Battery capacity

Although it depends on usage, it is said to reach the end of its service life after 500 repeated charge and discharge cycles. In the example below, after 500 repeated charge and discharge cycles, the full charge capacity of 1,000mAh is reduced to 750mAh, and after another 700 cycles, the capacity is reduced to 600mAh.

Batteries deteriorate! Four points to prevent unnecessary deterioration (1/2) - FMV Support : Fujitsu PCs


Second, the voltage of a lithium-ion battery is 3.7V, so there is a loss in the process of boosting the voltage to match the standard USB voltage of 5.0V, or being released as heat. As a result, only about 60% of the mobile battery's stated capacity can actually be charged. A 10,000 mAh mobile battery in its new condition can charge an iPhone 13 with 3,227 mAh, which is about 2 times, or a Google Pixel 6 with 4,614 mAh, which is about 1.5 times. Considering weight and lifespan, I would recommend the 10,000 mAh mobile battery.

fast charge

As lightly mentioned earlier, the electricity that can be supplied by the normal USB standard is as follows

type USB 2.0 USB3.x
Supply voltage 5V 5V
Supply current 900mA 900 ~ 1,500mA


This is too slow for charging, so the USB standard, which was created to allow for greater power flow, allows for fast charging. Initially, there were various standards in disarray, but now there are two

Charging the latest smartphones in a flash! The latest USB high-speed charging standard" - ELECOM


The mobile battery, cable, and device (smartphone, tablet, or laptop) must be compatible with the USB Power Delivery or Quick Charge standard. Specifically, which devices are compatible depends on the model, not strictly on the manufacturer. The following is a list of the latest models from each manufacturer at this time.

model PD support QC support
AQUOS sense 6 -
Galaxy S22 Ultra -
Google Pixel 6 -
iPhone 13 -
OPPO Reno 5
Xperia 8 -
Zenfone 8


Other Functions

Battery level check

Information on how much charge is left is always information that we would like to know.


We have determined that built-in cables, integrated batteries and plugs, and wireless charging are less important and will not be included in this blog.

Product Comparison Chart

Considering the above, the following mobile batteries are recommended.

  • lithium-ion battery
  • At least 8 cm long and 2 cm thick
  • Quick Charging Support
  • Battery level can be checked

The table below compares mobile batteries with a capacity of 10,000 mAh.

Manufacturer Anker Anker
model number PowerCore 10000 PD Redux PowerCore Speed 10000 QC
Battery level check
PD -
QC -
size 106 x 52 x 25 mm 100 x 63 x 22mm
weight 192g 198g
Price*1 4,490 yen -

*1...Price on Amazon on April 8, 2023.


In many cases, they were lithium polymer batteries or less than 2 cm thick, and Anker was the only model that made it to the table.

As a result, we recommend Anker's PowerCore 10000 PD Redux.


A USB Power Delivery compatible cable is included with the mobile battery, but a charger is required separately. The following product has two ports and can quickly charge a MacBook Air.

I hope the above is helpful.