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Application of lithium-ion battery energy storage technology

(From Ofweek)

Lithium-ion battery energy storage technology mainly refers to the storage of electric energy. The stored energy can be used as emergency energy, energy storage when the grid load is low, and output energy when the grid load is high, for peak shaving and valley filling, and to reduce grid fluctuations.

Lithium-ion batteries refer to accumulators made of lithium-containing compounds, which mainly rely on lithium ions to move between the positive and negative electrodes to work. In addition to being used as a power lithium battery, lithium-ion batteries can also be used as energy storage batteries. Due to the high safety of lithium-ion batteries, most energy storage power stations choose lithium-ion ferrous phosphate batteries as energy storage batteries.

Lithium-ion batteries are currently the most common energy storage technology on the market, and are widely used in various personal electronic products, mobile devices and even vehicle batteries for electric vehicles. Lithium batteries are usually referred to as lithium-ion batteries, which are generally divided into energy storage lithium batteries and power lithium batteries according to their uses. Lithium batteries for energy storage are used in photovoltaics or UPS. The internal resistance is relatively large, charging and discharging speed is slow, generally 0.5-1C. Power batteries are generally used in electric vehicles. The internal resistance is small, and the charging and discharging speed is fast, generally reaching 3- 5C, the price is about 1.5 times more expensive than energy storage batteries.

Lithium-ion batteries rely primarily on the movement of lithium ions between the positive and negative electrodes to function. In the process of charging and discharging, there are only lithium ions, and there is no metal lithium. Compared with other batteries, the advantages of lithium batteries are: high energy density, long cycle life, low self-discharge rate, high energy conversion rate, fast charge and discharge, etc.

However, lithium-ion battery energy storage power stations are generally used in new energy power stations, and are relatively less used in traditional power stations. Due to the unstable voltage and the uncertain timing of wind and solar power generation, it is more conducive to grid operation to use energy storage power stations as power relays.

The currently popular lithium titanate material is also worthy of attention. It can replace graphite as an anode material. Although the energy density is not high, lithium titanate allow the battery to achieve high-rate charge and discharge, and has excellent safety performance and long cycle life.

It is understood that the application scenarios of lithium batteries on the power supply side, user side, and grid side of energy storage are as follows: energy storage applications on the power generation side include photovoltaic storage power stations, wind storage power stations, and AGC frequency modulation power stations; Storage and charging stations, home energy storage, backup power, etc., scenarios such as grid energy storage, substation energy storage, virtual power plants, peak shaving/frequency modulation, etc.

So far, for different fields and different needs, people have proposed and developed a variety of energy storage technologies to meet the application. Lithium-ion battery energy storage is currently the most feasible technical route.

From the perspective of the economics of energy storage technology, lithium-ion batteries have strong competitiveness, while sodium-sulfur batteries and vanadium redox flow batteries have not yet formed industrialization, supply channels are limited, and the cost is high. From the perspective of operation and maintenance costs, sodium-sulfur batteries need continuous heating, vanadium redox flow batteries need pumps for fluid control, which increases operating costs, while lithium-ion batteries require almost no maintenance.

According to public data, there are already 20 lithium-ion battery energy storage projects in China, with a total installed capacity of 39.575MW. Energy storage is one of the important means to solve the intermittent volatility of new energy wind power and photovoltaics, and realize the function of peak shaving and flat valley. Energy storage lithium-ion batteries are also gradually being valued as an emerging application scenario.

Lithium-ion battery is a very important energy storage technology, widely used in portable electronic devices and new energy vehicles, the cost of global energy storage batteries is continuing to decline. However, future energy storage methods will shift from lithium-ion batteries to more abundant and innovative solutions.

China’s Lithium-ion Battery Export Industry Report 2022

In 2022, China’s lithium battery exports were nearly 342.66 billion yuan.

Lithium battery products are becoming a new growth point for China’s foreign trade exports.

According to statistics from the General Administration of Customs of China, the export value of lithium-ion batteries in China was close to 342.656 billion yuan in 2022, an increase of 86.7% compared with 183.526 billion yuan in 2021. Compared with the growth rate of 66.5% in 2021, the growth rate in 2022 has also increased significantly by 20.2 percentage points.

From the perspective of export countries, the top five countries in domestic lithium battery exports in 2022 are the United States, Germany, South Korea, the Netherlands and Vietnam, accounting for 57.6% of the total export value. Among these, the amount of domestic lithium batteries exported to the United States was 68.21 billion yuan, year-over-year increase of 112%, 52.33 billion yuan and 35.47 billion yuan exported respectively to Germany and South Korea.

The United States has become the largest exporter of China’s lithium batteries for three consecutive years, accounting for about 19.9%.

On February 2, Li Xingqian, director of the Foreign Trade Department of the Ministry of Commerce, said that last year, represented by the export of electric vehicles, photovoltaic products, and lithium batteries, Chinese high-tech, high value-added products that lead green transformation have become new growth points for exports.

According to data previously released by EVTank, a domestic information organization, the overall global lithium battery shipments in 2022 was 957.7GWh, a year-over-year increase of 70.3%. In 2022, China’s lithium-ion battery shipments reached 660.8GWh, a year-over-year increase of 97.7%, accounting for 69.0% of the global lithium-ion battery shipments. In 2021, China’s lithium-ion battery shipments accounted for 59.4%.

According to EVTank analysis, in the next ten years, lithium-ion batteries will still be the main battery technology route in the field of new energy vehicles and energy storage. By 2030, the global sales of new energy vehicles will reach 52.12 million, the development of the energy storage industry will also greatly stimulate the demand for lithium-ion batteries. EVTank predicts that by 2025 and 2030, global lithium-ion battery shipments will reach 2211.8GWh and 6080.4GWh respectively, with a compound growth rate of 22.8%.

In 2022, lithium carbonate imports increased by 68% year-over-year.

It is worth noting that, corresponding to the substantial increase in lithium battery exports, China’s imports of battery raw materials lithium concentrate and lithium carbonate also increased significantly in 2022.

According to custom data, from January to December 2022, China imported about 2.84 million tons of lithium concentrate, mainly from Australia, Brazil, Zimbabwe, Canada and other countries, an increase of about 42% year-over-year. In 2022, the annual import of lithium carbonate reached 136,000 tons, a year-over-year increase of 68%, and the growth rate increased by 6.3 percentage points compared with 2021. An increase of about 72%.

In 2022, the apparent consumption of lithium carbonate in China will reach 474,300 tons, and the import dependence of lithium carbonate was 26.2%.

Among them, lithium carbonate from Chile was 12.17 tons, accounting for 89.5% of the total imports; lithium carbonate from Argentina was 12,800 tons, accounting for 9.4% of the total imports. The combined lithium carbonate imports of the two countries accounted for 98.9% of the total imports.

Shanghai is the province with the highest import volume of lithium carbonate in China. According to statistics from Shanghai Customs, in 2022, the cumulative import of lithium carbonate, a raw material for lithium batteries, in Shanghai was 84,000 tons, a year-over-year increase of 89.9%.

In addition, China’s net export of lithium hydroxide was 90,300 tons in 2022, a year-over-year increase of about 29%.

At present, China has become the world’s largest exporter of lithium hydroxide, and more than 95% of its products are exported to Japan and South Korea. Among them, lithium hydroxide exported to South Korea has surpassed that of Japan, accounting for 63%.

Why is China a net importer of lithium carbonate, but a net exporter of lithium hydroxide? According to the analysis of Shanghai Nonferrous Network, lithium hydroxide is mainly used as a raw material for high-nickel ternary lithium batteries, and more production and consumption in foreign markets Most of them are high-nickel batteries and supporting cars. On the contrary, the domestic demand for lithium hydroxide is relatively limited, but more than 90% of the world’s current lithium hydroxide smelting capacity is concentrated in China, this has resulted in differences in the supply and demand structures of the two markets at home and abroad.

China has become a net importer of lithium carbonate since May 2019. At that time, with the rapid decline in domestic lithium carbonate prices, a large number of overseas lithium carbonate products flooded into the Chinese market, many overseas salt lake companies also focused on the Chinese market for lithium carbonate sales.

In addition, the lithium products extracted from salt lakes in South America are basically lithium carbonate, and the integrated production capacity of salt lake resources and lithium processing is mature, so the average price of imported lithium carbonate is far lower than the domestic spot price of lithium carbonate. Taking December 2022 as an example, the average import price of lithium carbonate in that month was 384,700 yuan/ton, which was far lower than the domestic battery-grade lithium carbonate price of about 500,000 yuan/ton in December.

According to the forecast of industry organizations, with the increase of production by leading lithium extraction enterprises in South American salt lakes and the continued expansion of China’s domestic lithium battery production capacity, the demand for raw materials will increase. From 2023 to 2032, China’s lithium carbonate imports will continue to grow.

Battery Safety: Why do I need to use the same type and brand of battery?

Why do I need to use the same type and brand of battery? Why is the mix of old-new and other battery types bad?

It is highly advisable to use batteries of the same type, brand, size and expiry date in one appliance. The electrical capacity of different types or batches can differ. If such different batteries are used the difference in electrical capacity will grow during usage which could eventually cause one of the batteries to over discharge, leak and even explode.

Never use old and new batteries together, as this may cause leakage or worse. The remaining electrical capacity in a used battery is less than a new battery, even when it was only used shortly. This causes that when used together with one or more fresh batteries, that this used battery will lose capacity and voltage faster than the new batteries, which could cause eventually an over discharge and leakage of that battery.

Do not mix old and new as the new battery will start charging old battery in one group that will make the new battery fade quickly. The mixed use of different types and specifications will cause serious safety hazards. The mixed use of different brands, specs., old and new will also reduce the performance of batteries and affect stability and consistance.

Charged up: the history and development of batteries

(Authors  Jose Alarco / Peter Talbot)

Batteries are so ubiquitous today that they’re almost invisible to us. Yet they are a remarkable invention with a long and storied history, and an equally exciting future.

A battery is essentially a device that stores chemical energy that is converted into electricity. Basically, batteries are small chemical reactors, with the reaction producing energetic electrons, ready to flow through the external device.
Batteries have been with us for a long time. In 1938 the Director of the Baghdad Museum found what is now referred to as the “Baghdad Battery” in the basement of the museum. Analysis dated it at around 250BC and of Mesopotamian origin.

Controversy surrounds this earliest example of a battery but suggested uses include electroplating, pain relief or a religious tingle.

American scientist and inventor Benjamin Franklin first used the term “battery” in 1749 when he was doing experiments with electricity using a set of linked capacitors.

The first true battery was invented by the Italian physicist Alessandro Volta in 1800. Volta stacked discs of copper (Cu) and zinc (Zn) separated by cloth soaked in salty water.

Wires connected to either end of the stack produced a continuous stable current. Each cell (a set of a Cu and a Zn disc and the brine) produces 0.76 Volts (V). A multiple of this value is obtained given by the number of cells that are stacked together.

One of the most enduring batteries, the lead-acid battery, was invented in 1859 and is still the technology used to start most internal combustion engine cars today. It is the oldest example of rechargeable battery.
Today batteries come in a range of sizes from large Megawatt sizes, which store the power from solar farms or substations to guarantee stable supply in entire villages or islands, down to tiny batteries like those used in electronic watches.

Batteries are based on different chemistries, which generate basic cell voltages typically in the 1.0 to 3.6 V range. The stacking of the cells in series increases the voltage, while their connection in parallel enhances the supply of current. This principle is used to add up to the required voltages and currents, all the way to the Megawatt sizes.
There is now much anticipation that battery technology is about to take another leap with new models being developed with enough capacity to store the power generated with domestic solar or wind systems and then power a home at more convenient (generally night) time for a few days.

How do batteries work?
When a battery is discharged the chemical reaction produces some extra electrons as the reaction occurs. An example of a reaction that produces electrons is the oxidation of iron to produce rust. Iron reacts with oxygen and gives up electrons to the oxygen to produce iron oxide.

The standard construction of a battery is to use two metals or compounds with different chemical potentials and separate them with a porous insulator. The chemical potential is the energy stored in the atoms and bonds of the compounds, which is then imparted to the moving electrons, when these are allowed to move through the connected external device.

A conducting fluid such as salt and water is used to transfer soluble ions from one metal to the other during the reaction and is called the electrolyte.

The metal or compound that loses the electrons during discharge is called the anode and the metal or compound that accepts the electrons is called the cathode. This flow of electrons from the anode to the cathode through the external connection is what we use to run our electronic devices.

Primary vs rechargeable batteries
When the reaction that produces the flow of electrons cannot be reversed the battery is referred to as a primary battery. When one of the reactants is consumed the battery is flat.

The most common primary battery is the zinc-carbon battery. It was found that when the electrolyte is an alkali, the batteries lasted much longer. These are the alkali batteries we buy from the supermarket.

The challenge of disposing with such primary batteries was to find a way to reuse them, by recharging the batteries. This becomes more essential as the batteries become larger, and frequently replacing them is not commercially viable.

One of the earliest rechargeable batteries, the nickel-cadmium battery (NiCd), also uses an alkali as an electrolyte. In 1989 nickel-metal hydrogen batteries (NiMH) were developed, and had a longer life than NiCd batteries.
These types of batteries are very sensitive to overcharging and overheating during charge, therefore the charge rate is controlled below a maximum rate. Sophisticated controllers can speed up the charge, without taking less than a few hours. In most other simpler chargers, the process typically takes overnight.

Portable applications – such as mobile phones and laptop computers – are constantly looking for maximum, most compact stored energy. While this increases the risk of a violent discharge, it is manageable using current rate limiters in the mobile phone batteries because of the overall small format. But as larger applications of batteries are contemplated the safety in large format and large quantity of cells has become a more significant consideration. The first mobile phone had a large battery and short battery life – modern mobile and smart phones demand smaller batteries but longer lasting power.

First great leap forward: lithium-ion batteries
New technologies often demand more compact, higher capacity, safe, rechargeable batteries. In 1980, the American physicist Professor John Goodenough invented a new type of lithium battery in which the lithium (Li) could migrate through the battery from one electrode to the other as a Li+ ion.

Lithium is one of the lightest elements in the periodic table and it has one of the largest electrochemical potentials, therefore this combination produces some of the highest possible voltages in the most compact and lightest volumes.
This is the basis for the lithium-ion battery. In this new battery, lithium is combined with a transition metal – such as cobalt, nickel, manganese or iron – and oxygen to form the cathode. During recharging when a voltage is applied, the positively charged lithium ion from the cathode migrates to the graphite anode and becomes lithium metal.
Because lithium has a strong electrochemical driving force to be oxidised if allowed, it migrates back to the cathode to become a Li+ ion again and gives up its electron back to the cobalt ion. The movement of electrons in the circuit gives us a current that we can use.

The second great leap forward: nano technology
Depending on the transition metal used in the lithium-ion battery, the cell can have a higher capacity but can be more reactive and susceptible to a phenomenon known as thermal runaway.

In the case of lithium cobalt oxide (LiCoO2) batteries made by Sony in the 1990s, this led to many such batteries catching fire. The possibility of making battery cathodes from nano-scale material and hence more reactive was out of the question. But in the 1990s Goodenough again made a huge leap in battery technology by introducing a stable lithium-ion cathode based on lithium iron and phosphate.This cathode is thermally stable. It also means that nano-scale lithium iron phosphate (LiFePO4) or lithium ferrophosphate (LFP) materials can now be made safely into large format cells that can be rapidly charged and discharged.

Many new applications now exist for these new cells, from power tools to hybrid and electric vehicle. Perhaps the most important application will be the storage of domestic electric energy for households.

Electric cars
The leader in manufacturing this new battery format for vehicles is the Tesla electric vehicle company, which has plans for building “Giga-plants” for production of these batteries. The size of the lithium battery pack for the Tesla Model S is an impressive 85kWh. This is also more than enough for domestic household needs, which is why there has been so much speculation as to what Tesla’s founder Elon Musk is preparing to reveal this week.
A modular battery design may create battery formats that are somewhat interchangeable and suited to both vehicle and domestic applications without need for redesign or reconstruction.

Perhaps we are about to witness the next generational shift in energy generation and storage driven by the ever-improving capabilities of the humble battery.

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