Den voksende efterspørgsel efter mindre, lettere og mere kraftfulde bærbare elektronik afhænger af fremskridt i Lithium-ion (Li-ion) batteri teknologi. At designe batteripakker til moderne enheder kræver afbalancering af energitæthed, sikkerhed, størrelse, vægt, omkostninger og lovgivningsmæssig overholdelse.
Batteripakke -dimension og vægtbegrænsninger
Større batteripakker leverer normalt højere strøm i længere varighed.
Imidlertid står bærbare enheder over for vægt og pladsbegrænsninger, hvilket kræver, at producenterne designer lette pakker, der stadig giver betydelig strøm.
Lithium-ion-batterier fås i forskellige formater til disse enheder, herunder Cylindrisk, prismatiskog posepolymerceller.
Cylindriske celler (f.eks. 18650, 26650, 21700)
Cylindriske celler er med moden fremstilling, høj specifik energi (200-260 WH/kg), fremragende termisk styring og omkostningseffektivitet. Men deres stive form begrænser volumetrisk energitæthed (500-600 WH/L) og designfleksibilitet.
Integrering af flere celler tilføjer kompleksitet og ineffektiv plads. De bruges ofte i bærbart medicinsk udstyr, håndholdte kommercielle og militære værktøjer og elværktøj.
Prismatiske celler
Prismatiske celler har et rektangulært hus og tilbyder typisk højere volumetrisk energitæthed (600-700 WH/L) end cylindriske celler på grund af bedre pladsudnyttelse.
De har mellemliggende designfleksibilitet, men kan have lidt lavere specifik energi (160-220 WH/kg) og højere omkostninger pr. KWh. Termisk styring kan også være mere udfordrende.
Polymerceller (poseceller)
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 Batteripakker 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 termisk flugt. Regulations mandate BMS installation for all Lithiumbaserede batterier, 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 BMS 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.
Konklusion
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 Brugerdefineret batteripakkeproducent like Holo Battery can help determine the right technology and features to ensure your battery pack functions effectively, remains reliable, and is safe.
