能源收集存儲(chǔ)選項(xiàng)：可充電電池，超級(jí)電容器，或兩者兼而有之？

　　當(dāng)能量源不穩(wěn)定且不可預(yù)測(cè)時(shí)，能量收集也許更精確地稱為“能量清除”——這是一種越來(lái)越可行的供電方式，而無(wú)需提供外部電源或定期更換電池。這實(shí)際是由多種因素造成的：更好的儲(chǔ)能元件，改進(jìn)的電源管理組件，并可以操作和執(zhí)行有用的功能電路，如記錄和報(bào)告使用無(wú)線只是微安和毫瓦的功率數(shù)據(jù)。

　　能量收集系統(tǒng)由四個(gè)主要功能組成：一個(gè)能量源（換能器），一個(gè)儲(chǔ)能元件，一個(gè)啟動(dòng)過(guò)程中的整體管理控制器，收獲，操作模式（通常是重疊的）；以及負(fù)載本身（圖1）。我們來(lái)看看最常見的兩種儲(chǔ)能元件：可充電電池（在大多數(shù)情況下，鋰化學(xué)變化）和超級(jí)電容器（也稱為超級(jí)電容和超級(jí)電容，雖然正式名稱是雙電層電容器）。

　　Figure 1： Four functional elements are common to all energy-harvesting designs： the source transducer， the energy-storage element， the load， and a system controller or power-management unit.

　　Both are good options， but they have some operational differences with respect to capacity/power and energy density， charge/discharge cycles， discharge depth， form factor， ruggedness， load transient performance， lifetime， and cost. How you assess and weight these parameters depends， of course， on your application specifics， priorities， and constraints.

　　An important caution to keep in mind： the terms “energy” and “power” are both used in energy-harvesting applications. They are intimately related， of course： power is the rate which energy is being used （work is being done）， and energy is the time-integral of power—but depending on your application and which part of its operational cycles you are at， you may be more interested in one than the other. So be careful in your use of these words， and be sure you know which one you really are concerned with at any given instant.