The growing demand for smaller, lighter, and more powerful portable electronics depends on advancements in lithium-ion (Li-ion) battery technology. Designing battery packs for modern devices requires balancing energy density, safety, size, weight, cost, and regulatory compliance.
Battery Pack Dimension and Weight Limitations
Larger battery packs usually deliver higher current for longer durations.
However, portable devices face weight and space limitations, requiring manufacturers to design lightweight packs that still provide substantial power.
Lithium-ion batteries are available in various formats for these devices, including أسطواني، المنشورية, and pouch polymer cells.
Cylindrical Cells (e.g., 18650, 26650, 21700)
Cylindrical cells are with mature manufacturing, high specific energy (200-260 Wh/kg), excellent thermal management, and cost-effectiveness. But their rigid shape limits volumetric energy density (500-600 Wh/L) and design flexibility.
Integrating multiple cells adds complexity and inefficient space. They are commonly used in portable medical devices, handheld commercial and military tools, and power tools.
Prismatic Cells
Prismatic cells have a rectangular casing and typically offer higher volumetric energy density (600-700 Wh/L) than cylindrical cells due to better space utilization.
They have intermediate design flexibility but may have slightly lower specific energy (160-220 Wh/kg) and higher cost per kWh. Thermal management can also be more challenging.
Polymer Cells (Pouch Cells)
Polymer cells have flexible aluminum laminate casings and high volumetric energy density (600-800 Wh/L), making them suitable for thin or irregular shapes.
They offer a good weight-to-capacity ratio (250-300 Wh/kg) but lack mechanical rigidity, needing strong structural support.
Challenges include thermal management and manufacturing costs. These cells are often used in portable devices like wearables, medical equipment, drones, laptops, and tablets.
Watt Hour Limitations
A key design parameter is total energy capacity, measured in Watt-hours (Wh = Voltage * Amp-hours). Increasing Wh extends runtime but also increases size, weight, and cost.
Safety regulations impose strict limits on Wh for air travel: Cells under 20 Wh and حزم البطارية under 100 Wh are allowed without restrictions.
Packs between 100-160 Wh require airline approval, with a maximum of two per passenger or spares. Packs over 160 Wh are typically banned as carry-on. These regulations significantly impact the maximum energy available for high-performance ultraportables like premium laptops.
Charging Design Options
Charging lithium-ion batteries requires specific parameters.
Unlike other batteries, they need dedicated chargers due to manufacturer design variations affecting current and voltage settings.
With lower resistance, lithium-ion cells enable faster charging, so chargers must deliver the correct current without overcharging or undercharging. Custom chargers for specific battery packs are preferred over off-the-shelf models.
BMS Designs
Battery management systems (BMS) protect lithium-ion batteries from issues like high temperatures, overcharging, undercharging, and هارب حراري. Regulations mandate BMS installation for all البطاريات القائمة على الليثيوم, including portable devices.
For portables, BMS features include temperature monitoring, overcharging and discharging management, and fault diagnosis.
Interoperability is also essential for communicating battery condition across networks and controller systems.
Enclosure Special Features
Safety is crucial for portable devices using lithium-ion batteries. These batteries must be protected from punctures and damage if the device is dropped or mishandled.
Circuit protection, like polymeric positive temperature coefficient (PPTC) devices, can safeguard circuits during shipping and transport.
Enclosures also protect lithium-ion batteries from shocks and vibrations while allowing gas venting and heat dissipation.
Manufacturers offer various enclosure options, including shrink wrap, vacuum-formed plastic, and injection-molded plastic, which undergo safety drop testing to ensure durability and reliability.
Portability Regulations
Transportation regulations for lithium-ion batteries apply to both portable and non-portable devices.
All lithium batteries must include نظام إدارة المباني components, whether shipped separately or installed. They are limited to a maximum of 100 watt-hours unless approved by the carrier. Portable devices require safety testing and certification.
Starting January 2026, lithium-ion batteries shipped alone must have a state of charge (SoC) of 30% or less. Additionally, packaging for non-specification shipping must meet the 3. 0 meter stack test if containing batteries within or packed with devices.
خاتمة
Designing lithium-ion battery packs for portable devices depends on the device’s needs, industry standards (such as those for medical or military use), and necessary regulations. A الشركة المصنعة للحزمة البطارية المخصصة like Holo Battery can help determine the right technology and features to ensure your battery pack functions effectively, remains reliable, and is safe.
