On August 31, 2026, the Ministry of Economy, Trade and Industry (METI) of Japan held a joint meeting of the Safety and Consumer Product Safety Subcommittee under the Industrial Structure Council and the Product Safety Committee of the Consumer Economic Council. The meeting submitted the document Initiatives on Product Safety. One of the confirmed policy directions is to reclassify mobile power banks (モバイルバッテリー) from the self-declaration scheme under Circle PSE to the third-party conformity inspection scheme under Diamond PSE.

For manufacturers exporting power banks to Japan, this change is far more than “re-testing products and replacing the marking”. The scope of inspection will be expanded from finished products to the whole manufacturing process.

I. Background: Accident Cases Quadrupled in Four Years

Mobile power banks are not newly added to Japan’s regulatory scope. On February 1, 2018, METI revised the interpretation of electrical appliance categories, bringing portable lithium-ion cells and battery packs with an energy density above 400Wh/L under the Electrical Appliance and Material Safety Law. Starting from February 1, 2019, non-compliant products were prohibited from production, import and sale, and products must bear the Circle PSE mark.

Nevertheless, the existing scheme follows a self-check and self-declaration model: manufacturers or importers verify compliance with technical standards on their own, file a notification with METI, and then affix the PSE mark. The effectiveness of supervision under this system has long been questioned.

Rising accident statistics reflect the safety risks. According to NITE (National Institute of Technology and Evaluation), the number of safety incidents involving lithium-ion power banks surged from 51 cases in 2021 to 192 cases in 2025. In August this year, a power bank fire broke out on a train of the Midosuji Line of Osaka Metro, disrupting service. Japan has also introduced restrictions on the use of power banks inside passenger cabins.

Most fires occur in enclosed public transport such as subways and buses. Once ignition and smoke happen, secondary disasters can easily follow. In addition, cross-border e-commerce enables low-quality products to reach consumers directly, shifting the regulatory focus from offline retail stores to online marketplaces.

II. Three Major Changes: More Than Marking from ○ to ◇

Based on meeting documents and Japanese media reports, the revision covers three core dimensions: inspection authority, applicable standards and inspection coverage. The comparison table below shows the differences clearly.

表格

In short: previously, passing product testing was sufficient; manufacturers will now need to prove that their production line can consistently manufacture compliant products.

III. Timeline: Enforcement in March 2027 with a 12-Month Transition Period

表格

Note: The above schedule is extracted from meeting materials. Ministerial ordinances have not been released yet, and the timeline is subject to adjustment.

IV. Impacts on Export Enterprises

1. Revised certification route. Diamond PSE requires Japan-registered inspection bodies, usually accompanied by factory audits. The lead time and cost will be higher than the existing self-declaration scheme. Testing and audit schedules may become tight when a large number of manufacturers submit applications.
2. Traceable supply chain management. Records of cell incoming inspection, foreign object prevention, key process parameters and batch traceability must be available. The previous practice relying merely on finished product sampling will not satisfy factory audit requirements.
3. Clarified accountability. The revised version of Japan’s Four Product Safety Laws came into force on December 25, 2025. Overseas sellers who sell regulated products directly to Japanese consumers via e-commerce platforms are classified as “specified importers”. They are required to file notifications with METI and appoint a domestic administrator in Japan.
4. Avoid rush stock preparation or redesign for existing SKUs. Rules for legacy models during the transition period and compliance judgment criteria will be specified in the upcoming ordinances. Blind bulk stocking may result in non-compliant inventory.

V. Recommendations for Manufacturers

1. Clarify product scope. Confirm whether your product falls under the definition of “mobile power bank” in this revision. Products with AC outlets such as portable power stations will be assessed separately after the final official text is released.
2. Evaluate cells and protection circuits. Overcharge, overdischarge and short-circuit protection design, as well as charge-discharge control logic, will be key assessment items under the tightened technical standards.
3. Complete quality documentation. Conduct internal audits covering foreign object control, key process parameters, inspection records and traceability systems in preparation for factory inspection.
4. Schedule certification in advance and prepare documents. Japanese manual, label information, importer details and consistency between test reports and physical samples are common bottlenecks for approval. Early preparation is strongly advised.

Closing Remarks

GTG Energy Storage Testing will keep tracking official updates from Japan and release in-depth interpretations once formal standards are published. If you have questions about power bank certification for the Japanese market, feel free to contact our team. We can help coordinate PSE testing transition and support smooth testing and factory audit arrangements.