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All colleagues unite and focus their efforts to write a new chapter of developmentSafety Requirements for Lithium-Ion Battery Chargers and UL Certification Standards for Chargers
所属分类： Industry News
发布时间：2020-07-14
Battery technology continues to advance alongside today’s rapid technological progress and growing environmental awareness. Rechargeable batteries, with their ability to be reused repeatedly, are now widely employed in numerous portable 3C devices, such as mobile phones, MP3 players or iPods, digital cameras, and laptops.
As the safety of rechargeable batteries has become a matter of widespread public concern, we must also not overlook the developments that accompany them— Charger Safety requirements. In response to the trend toward increasingly compact and multifunctional 3C products, battery technologies must also evolve, becoming smaller in size. However, whether they are nickel‑cadmium, nickel‑metal hydride, lithium‑ion, or lithium‑polymer batteries, all carry the potential—due to insufficient design—to harbor substantial hazardous energy that could cause injury or even death. This is one of the primary reasons why battery safety standards have continued to attract international attention in recent years.
UL has progressively developed corresponding standards to serve as evaluation criteria for the safety of various battery products, and these standards have earned widespread recognition within the industry. As battery technology continues to advance, it is essential to extend safety considerations to charger products as well. Once a battery is fully charged, it effectively becomes another DC power source at the charger’s output terminal—beyond the mains power outlet. If the charger is improperly designed or if internal components fail or short‑circuit, hazards can arise. For example, if the energy from a fully charged battery is fed back into the charger via its output terminals or connectors, the insulation inside the charger may overheat and degrade, leading to melting of the housing and potentially even causing a fire. Several years ago, the United States experienced a similar incident: a fully charged battery caused a short circuit in the charger’s internal output wiring, creating an extremely high‑current discharge path that overheated the unit, resulting in the breakdown of the isolation transformer’s insulation and the melting of the housing. Because chargers and their associated rechargeable batteries must be designed to meet the requirements of their intended end‑use applications, UL has established a series of safety standards tailored to different types of power‑supply products. For instance, UL 1310 evaluates chargers with Class 2 outputs; UL 1012 assesses chargers for non‑automotive batteries; UL 1236 covers chargers for automotive batteries; and UL 1564 addresses chargers for golf‑cart electric vehicles, among others.
Among the safety‑assessment requirements, the most noteworthy is the newly introduced “Backfeed Protection” (BFP) provision, which stems from the aforementioned U.S. case. This applies to chargers covered by UL 1310 and UL 1012. In addition to mandating that the product’s design incorporate a backfeed‑protection feature at the output, UL also requires that actual product testing include an independent evaluation of backfeed protection. Because chargers pose greater potential hazards than typical power supplies, both their structural design and testing criteria are more stringent, with additional provisions aimed at simulating abnormal conditions users may encounter during charging. To provide an extra layer of user protection, charger labeling is also subject to UL review; for instance, products must bear explicit markings such as “Backfeed Protection” or “BFP,” and the accompanying user manual must clearly specify the types, models, and quantities of batteries approved for use with that charger.