Advanced algorithms and hardware for intelligent batteries

New portable equipment tends to use rechargeable (secondary) batteries because they are cost-effective over the lifetime of the product. Manufacturers who use rechargeable batteries also need advanced electronics to accurately predict a battery's fuel capacity and quickly recharge the battery. All of this capability is needed in a compact, cost-effective package. National Semiconductor is introducing packaged solutions that meet a user's needs. This paper discusses the problem and shows how a joint hardware and firmware package solves a wide range a users needs. Portable notebook computers are a significant portion of the market size where a National solution fits. The computer market uses numerous batteries (usually eight to ten in each computer battery pack) and users often buy an extra pack or two because they don't want to be caught short-charged. Every mobile computer's power management circuitry needs accurate charging and discharging algorithms. National's solution provides advanced algorithms that utilize NeuFuz (technology in standard product availability). This technique uses Ni-Cd (nickel-cadmium) and Ni-MH (nickel-metal-hydride) battery packs as its test vehicle. These chemistries represent challenges for state-of-charge determination, due to their discharge profile being nearly flat. It is equally difficult to terminate fast charging because relatively rapid temperature and voltage changes occur suddenly. National's method monitors several crucial battery parameters: cell temperature, pack voltage and current flowing into or out of the battery pack.<>