（2）儲能過程（原理）

什么是儲能？

儲能是指通過介質(zhì)或設(shè)備將能量轉(zhuǎn)化為在自然條件下較為穩(wěn)定的存在形態(tài)并存儲起來，以備在需要時釋放的循環(huán)過程。

儲能過程（原理） ：

1）變流器與逆變器

我在《光伏行業(yè)-逆變器》這篇文章里，講過儲能逆變器的原理，但那只是非常簡單介紹。

這里我要詳細介紹儲能的過程

在講儲能原理之前，我要先簡單介紹下變流器與逆變器。

直接用一句話總結(jié)： 逆變器是變流器的一種。

先看兩個名詞“整流電路”與“逆變電路 ”。

整流電路 ：將 交流電源 變成直流電源 ，這就是整流電路 。

(2) Energy storage process (principle)  

 

 

What is energy storage?  

 

 

 

Energy storage refers to a cyclic process in which energy is transformed into a stable form under natural conditions through media or equipment and stored for release when needed.  

 

 

 

Energy storage process (principle) :  

 

 

 

 

 

1) Converter and inverter  

 

 

 

In my article "Photovoltaic Industry - Inverters", I talked about the principle of energy storage inverters, but that was only a very brief introduction.  

 

 

 

Here I will introduce the process of energy storage in detail  

 

 

 

Before talking about the principle of energy storage, I want to briefly introduce converters and inverters.  

 

 

 

To sum up directly in one sentence: inverter is a kind of converter.  

 

 

 

First look at the two terms "rectifier circuit" and "inverter circuit".  

 

 

 

Rectifier circuit: The AC power supply into DC power supply, this is the rectifier circuit.  

 

 

 

Inverter circuit: The reverse process of converting a DC source into an AC source, corresponding to rectification, is defined as an inverter circuit.  

 

 

 

Then the converter can be defined as follows:  

 

 

 

Converter: Under certain conditions, a thyristor circuit can be used as both a rectifier circuit and an inverter circuit, this device is called converter.  

 

 

 

then  

 

 

 

"Photovoltaic inverter" is to talk about DC alternating current (because photovoltaic power generation is produced by direct current).  

 

 

 

"Energy storage inverter", "energy storage converter", "two-way energy storage inverter" can be called "converter".  

 

 

 

Therefore, it is hardly difficult for inverter manufacturers to produce energy storage converters.  The competitive pattern of inverter can evolve into the pattern of energy storage converter.  

 

 

 

For an introduction to PV inverters, the article is linked here: PV Industry - Inverters  

 

 

 

 

 

2) Energy storage process  

 

 

 

First look at the image below.  

 

The picture  

 

(Source: SunPower official website, one of the energy storage solutions)  

 

 

 

Note that the red line is the AC line and the blue line is the DC line.  

 

 

 

Note that this is only one solution, to clearly understand the storage process (there are other solutions, of course).  

 

 

 

The energy storage process is as follows:  

 

 

 

A. Daytime power generation: the photovoltaic array (DC) power generation is transformed into AC power through the photovoltaic inverter, and (transformer) is boosted to be used by the load end.  

 

 

 

If there is any surplus, it can be sold to the National Grid or stored.  

 

 

 

Whether to sell or store, or both.  

 

 

 

It depends on the time of day, because TOU prices are different, they can exist and they can be stored when the price is low, and they can be sold when the price is high.  

 

 

 

There is even arbitrage of price difference, such as storing electricity from the grid when the price is low and selling it when the price is high to earn the difference.  

 

 

 

B. electricity storage :(photovoltaic power generation) inexhaustible electricity (alternating current), (transformer) after voltage reduction, through the storage converter, into dc electricity, stored (charging) energy storage battery (usually lithium battery).  

 

 

 

C. Discharge at night: the discharge of energy storage battery (DC) is turned into AC through the storage converter, which is boosted by (transformer) for load use.   If not, it can be plugged in from the grid.  

 

 

 

(3) Energy storage classification  

 

 

Generally, energy storage can be divided into electric energy storage, thermal energy storage and hydrogen energy storage according to different forms of energy storage. 

逆變電路 ：將直流電源 變成 交流電源，這種對應(yīng)于整流的逆向過程，定義為逆變電路。

然后可以定義變流器如下：

變流器 ：在一定條件下，一套晶閘管電路既可以作整流電路又可作逆變電路，這種裝置稱為變流器。

那么

“光伏逆變器”就是講直流變交流（因為光伏發(fā)電發(fā)出來的是直流電）。

“儲能逆變器”、“儲能變流器”、“雙向儲能逆變器”都可以稱作“變流器”。

所以逆變器的生產(chǎn)廠家生產(chǎn)儲能變流器幾乎沒有難度。逆變器的競爭格局可以演變成儲能變流器的格局。

光伏逆變器的介紹，文章鏈接在這里：光伏行業(yè)-逆變器

2）儲能過程

先看下圖。

（資料來源：陽光電源官網(wǎng)， 其中一種儲能解決方案）

注意圖中紅色線是交流線，藍色線是直流線。

注意，這只是一種解決方案，是為了清楚理解儲能的過程（當然還有別的解決方案）。

儲能過程如下：

A、日間發(fā)電 ：光伏陣列 發(fā)電（直流）經(jīng)過 光伏逆變器 變成交流電，（變壓器）升壓后供負荷端使用。

如果有剩余，則可以賣給國家電網(wǎng)，或者存儲起來。

到底是賣還是存儲，或者二者都有。

這要看時段，因為分時電價不一樣，可以存在在電價低的時候存儲起來，電價高的時候賣出去。

甚至有差價套利的，比如在電價低的時候，將電網(wǎng)的電存儲起來，在電價高的時候賣出去，賺取差價。

B、儲電 ：（光伏發(fā)電）用不完的電（交流電），（變壓器）降壓后經(jīng)過 存儲變流器 ，變成直流電，存儲到（充電）儲能電池（一般是鋰電池）。

C、夜間放電 ：儲能電池放電（直流電）經(jīng)過 存儲變流器 ，變成交流電，（變壓器）升壓之后供負載使用。如果不足，還能夠從電網(wǎng)中接入。

（3）儲能分類

一般可根據(jù)能量存儲形式的不同分為 電儲能 、 熱儲能 和 氫儲能 三類。