Design Analysis of Battery-Based Power Management System

Battery-based systems are widely used in the fields of cellular phones, PDA games, medical instruments, and the like. These systems require efficient power management to optimize device size and battery life.

The battery-based power management system includes a battery and a voltage regulator circuit that supplies power to the system. The main design goals include:

Performance and charging time interval indicators, through an effective system design, to make the battery size the smallest and the lightest.

A suitable regulated output voltage is provided over a wide input voltage range, and the battery-based system operates normally as the battery voltage drops.

The power management system is required to reduce the printed circuit board size.

The minimum heat consumption of the power management system should eliminate complex thermal management, which increases weight and cost.

Optimized circuit wiring for power management systems should avoid electromagnetic interference.

Highly reliable power management system.

Battery Selection To meet the above design goals, the design of the power management system begins with the battery. The battery type has a primary battery (or non-rechargeable battery) and a rechargeable battery.

Some popular rechargeable batteries include:

Nickel-cadmium (NiCd) batteries have long life, high discharge rate and low cost. The advantage is a simple charging characteristic that can withstand multiple charges/discharges.

Nickel-metal hydride (NiMH) battery: It has a higher energy density than NiCd battery, but its energy density is 30%~40% higher than NiCd at the expense of life. The NiMH storage effect is relatively small. When charging, NiMH uses a more complex charging algorithm and consumes some heat, so the required charging time is longer than NiCd.

Lithium-ion (Li-ion) battery: high energy density and light weight. Today's lithium batteries are at the center of the cell at maximum electrochemical potential per unit weight and highest energy density. Lithium-ion batteries are safe and provide some safety measures when charging and discharging. Its energy density is twice that of a standard NiCd battery. In addition, it has a high capacity, its load characteristics are quite good, and the discharge characteristics are similar to those of NiCd. Its relatively high battery voltage (2.7~4.2V) makes many Li-ion battery packs consist of only one battery. The lifetime is 300 charge/discharge cycles and 50% capacity at 500 cycles. However, Li-ion batteries require a protection circuit that limits the peak voltage of each battery during charging and prevents the voltage drop from being too low during discharge. The protection circuit not only limits the maximum charge and discharge current, but also monitors the battery temperature. Care should be taken to short-circuit, overcharge, crush, knock, damage, penetrate, reverse polarity, expose to high temperatures or disassemble the battery when handling and testing Li-ion batteries.

Multi-purpose Tent Group

Canway multi-purpose tent groups are developed for those need large and different functional areas in fields. Typically, their fields of use involve medical care in fields, long-term military activities, team buildings and so on. These activities often need several functional areas in tents. For instance, the medical tent group include logistics support area, medical treatment area, decontamination area and so on These area tent groups constitute a hospital tent. These area tents are connectable and they can connect with each other according to the functional requirements. Inflatable tents and metallic frame tents are both suitable for the tent groups.