光伏行业-储能

（2）储能过程（原理）

什么是储能？

储能是指通过介质或设备将能量转化为在自然条件下较为稳定的存在形态并存储起来，以备在需要时释放的循环过程。

储能过程（原理） ：

1）变流器与逆变器

我在《光伏行业-逆变器》这篇文章里，讲过储能逆变器的原理，但那只是非常简单介绍。

这里我要详细介绍储能的过程

在讲储能原理之前，我要先简单介绍下变流器与逆变器。

直接用一句话总结： 逆变器是变流器的一种。

先看两个名词“整流电路”与“逆变电路 ”。

整流电路 ：将 交流电源 变成直流电源 ，这就是整流电路 。

(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. 

逆变电路 ：将直流电源 变成 交流电源，这种对应于整流的逆向过程，定义为逆变电路。

然后可以定义变流器如下：

变流器 ：在一定条件下，一套晶闸管电路既可以作整流电路又可作逆变电路，这种装置称为变流器。

那么

“光伏逆变器”就是讲直流变交流（因为光伏发电发出来的是直流电）。

“储能逆变器”、“储能变流器”、“双向储能逆变器”都可以称作“变流器”。

所以逆变器的生产厂家生产储能变流器几乎没有难度。逆变器的竞争格局可以演变成储能变流器的格局。

光伏逆变器的介绍，文章链接在这里：光伏行业-逆变器

2）储能过程

先看下图。

（资料来源：阳光电源官网， 其中一种储能解决方案）

注意图中红色线是交流线，蓝色线是直流线。

注意，这只是一种解决方案，是为了清楚理解储能的过程（当然还有别的解决方案）。

储能过程如下：

A、日间发电 ：光伏阵列 发电（直流）经过 光伏逆变器 变成交流电，（变压器）升压后供负荷端使用。

如果有剩余，则可以卖给国家电网，或者存储起来。

到底是卖还是存储，或者二者都有。

这要看时段，因为分时电价不一样，可以存在在电价低的时候存储起来，电价高的时候卖出去。

甚至有差价套利的，比如在电价低的时候，将电网的电存储起来，在电价高的时候卖出去，赚取差价。

B、储电 ：（光伏发电）用不完的电（交流电），（变压器）降压后经过 存储变流器 ，变成直流电，存储到（充电）储能电池（一般是锂电池）。

C、夜间放电 ：储能电池放电（直流电）经过 存储变流器 ，变成交流电，（变压器）升压之后供负载使用。如果不足，还能够从电网中接入。

（3）储能分类

一般可根据能量存储形式的不同分为 电储能 、 热储能 和 氢储能 三类。