How Lithium-ion Batteries Work - The Scoop

Many people in the construction industry understand the basics of how internal combustion engines work — but what about the batteries used to power electric construction equipment? Now’s a great time to learn since battery-electric machines are becoming more common on jobsites.

For more information, please visit Godson Tech.

Most electric vehicles — like cars and Volvo electric machines — use lithium-ion batteries, which are rechargeable batteries also used in electronic devices such as mobile phones, laptops and more. They’re called “lithium-ion” because lithium ions move between two electrodes during the charging and discharging cycles to store and release energy.

Let’s take a deeper look at what makes up a lithium-ion battery and how the components inside work.

THE COMPONENTS OF A LITHIUM-ION BATTERY

First off, electricity can’t be captured and stored. It must be converted into another energy form (e.g chemical energy) which can then be stored.

Batteries are like fuel tanks — they don’t produce energy, but rather store it. In an internal combustion engine, the bond energies within gasoline or diesel molecules are broken and converted to heat, which in turn transforms into the mechanical energy needed to drive the piston inside the engine. Similarly, batteries store electricity from the power grid in the form of chemical potential and then discharge that energy to provide electricity when it’s needed.

Lithium-ion batteries contain four major components:

1. Anode (-)
2. Cathode (+)
3. Electrolyte
4. Separator

A battery must be connected to an external circuit (e.g. an electric machine or a mobile , as examples) to absorb and release energy. Electrons are the energy that provide the power. They move from the anode through the external circuit to the cathode while lithium ions stay inside the battery and move through the electrolyte to the other side — we’ll explain this more in a bit.

First, what are anodes, cathodes, separators and electrolytes? Let’s take a look:

• The anode (the negative end) is the “giver” in the battery. It releases or “gives” electrons and lithium ions to the cathode during discharge, and then it takes them back during charging. Anodes are typically made of carbon graphite because it arranges and stores lithium in an optimized state.
• The cathode (the positive end) is the “receiver” of the battery. It receives lithium ions during discharge, and then releases them during charging. Cathodes are typically made of metal-oxides [e.g., NMC (nickel, manganese and cobalt oxide), NCA (nickel, cobalt and aluminum) or LFP (lithium, iron and phosphate)] that want to take on available electrons.
• The electrolyte is a chemical solution (e.g. a liquid) between the anode and cathode that allows lithium ions to transfer back and forth between the anode and cathode.
• The separator is non-conductive, semipermeable and divides the anode and cathode. It allows only lithium-ions to pass through — it prevents electrons from doing the same. The electrons take a different path to the other side (through the external circuit that powers a machine or device). This selective permeability is crucial for the battery’s function and safety, as it prevents short circuits and ensures efficient energy storage and release.
  • Note: The separator is what keeps the chemical reactions inside a lithium-ion battery from getting out of control. This is why you’re always asked not to check lithium batteries on a plane.

WHY LITHIUM IS USED IN MOST RECHARGEABLE BATTERIES

Lithium is popular because it’s incredibly reactive and can store a lot of energy. This reactivity allows lithium-ion batteries to be small and lightweight, yet powerful — which is ideal for portable electronics and electric vehicles.

On the periodic table of elements, you’ll notice that Lithium is #3, meaning it has three protons (+) in its nucleus and three electrons (-) arranged in two “shells” around the nucleus — this electron arrangement is the key.

The first shell holds two electrons — further out, the second shell holds one. This single electron in the outer shell makes lithium highly reactive, as it wants to lose this electron to achieve a more stable configuration.

When lithium loses its electron, the remaining subatomic particles become what’s called an ion. An ion is simply an atom that has an electric charge because it either gained electrons, making it negatively charged, or lost electrons, making it positively charged. In this case, lithium loses an electron and becomes a positively charged lithium ion. This is where lithium-ion batteries get their name.

So, where do these lost electrons and newly formed lithium ions go?

HOW LITHIUM-ION BATTERIES WORK

To explain what’s happening, we’ll use the NMC (nickel, manganese and cobalt oxide) battery configuration on an electric machine as our example:

• To start, a battery is fully charged and not connected to a machine. The transfer of molecules that creates energy from the anode to the cathode cannot begin until they’re connected via a circuit — in this case, when the battery is turned on and the machine is being used.
• While the battery is discharging during use, lithium ions move from the anode (negative side) to the cathode — remember, the cathode wants electrons, and the lithium in the anode wants to give them up. This flow of electrons from the anode to the cathode is forced through the circuitry of the machine to power it. The electrons facilitate the transfer of energy from the battery to the machine, but they themselves do not get consumed.
• To help bring electrons over to the cathode, a conductive aluminum layer is added to this side.
• The electrons moving to the positive side of the battery start to build up a negative charge in the cathode — and electrons, which are negative, don’t like to move toward a negative environment. Remember, opposites attract — so to keep the reaction going, the anode simultaneously releases positive lithium ions to the cathode through the electrolyte inside the battery.

Once most of the lithium has moved from the anode to the cathode during discharge, the battery is empty.

DISCHARGING: LITHIUM IONS & ELECTRONS MOVE FROM ANODE TO CATHODE
CHARGING: LITHIUM IONS & ELECTRONS MOVE FROM CATHODE TO ANODE

• Then, when you plug the machine into an external power source to recharge it, the electrons on the cathode side are forced back to the anode side where they started. And as a result, the lithium ions once again pass through the electrolyte and separator back to the anode to produce a balanced system. What happens during machine charging is simply the opposite of what happens during discharging.
• To help bring electrons back to the anode, a conductive copper layer is added to this side.
• These opposite reactions are what make lithium-ion batteries rechargeable.

Over time, though, the irreversible nature of the process can change the chemistry and structure of battery materials, which, in turn, can reduce battery life and performance.

WHY WE USE NMC LITHIUM-ION BATTERIES AT VOLVO

It’s worth noting too that different types of lithium-ion batteries have slightly different chemistries. Still, they all rely on the movement of electrons and lithium ions between electrodes to store and release energy.

Are you interested in learning more about Lithium Battery for Electric Devices? Contact us today to secure an expert consultation!

The most common types of batteries are lead acid, nickel based and lithium-ion — and there are a few different kinds of lithium-ion batteries based on the material they’re made from. Here at Volvo, we’re currently using NMC (nickel, manganese, cobalt oxide) because they:

• have the most technological maturity
• are currently the easiest to manufacture
• have high energy density
• provide a long battery lifecycle
• are a safer option compared to some other configurations
• can be recycled

Lithium-ion batteries are superior to lead-acid batteries because they:

• have triple the energy density
• provide double the battery life
• consistently outperform in high-temperature applications
• charge quickly
• have no memory effect and no maintenance

Among lithium-ion batteries, NMC has better fast-charging capabilities, better cold-weather performance and a higher energy density when compared with LFP.

CHARGING TIPS FOR LITHIUM-ION BATTERIES IN ELECTRIC CONSTRUCTION EQUIPMENT

If you own electric heavy equipment, here are a few tips to help ensure you have plenty of power when you need it and limit battery degradation over time:

• Keep the electric machine at around 90% State of Charge and refrain from charging up to 100% too often.
• Avoid allowing the battery to get too low. If you can, don’t let your battery run down to 0%.
• If you aren’t going to use your electric machine for an extended period, keep it around 40-50% charged (a fully charged battery has a higher self-discharge rate).
• Try to use an AC slow charger at least once a week and let the battery management system (BMS) balance the battery packs.
• Pre-condition your machine, particularly during cold winter months. This may involve warming up the battery pack or machine to an appropriate temperature range to enhance the efficiency of the charging process. By preconditioning, the battery’s internal temperature is brought to an ideal level, allowing for more effective charging and potentially extending overall battery life.

Note that for Volvo electric equipment, the SOC window is between 10% and 90%, versus for cars where the SOC window is wider. An electric machine showing 0% SOC is actually 10% for the battery and showing 100% SOC is actually 90%.

We recognize this all may still seem a bit complicated, but a big part of that is because it’s still fairly new to our industry. Think about how confusing it can be for someone new to learn about how an internal combustion engine works. With time and experience, though, it all starts to make more sense — and this will too.

How many electronic devices do you use? These days, it is not odd for one person to be carrying several gadgets such as smartphones, tablet PCs, laptops, and wireless earphones. Did you know that Lithium-ion batteries power all those devices? Today, lithium-ion batteries dominate the battery industry. Let’s take a look at how they are structured and how they work.

Lithium ions in lithium-ion batteries move between cathode and anode, causing a chemical reaction and generating electricity.

A battery is charged when lithium ions move from cathode to anode, and is discharged when the lithium ions move back to the cathode as it releases energy. For this process to happen, the battery needs an electrolyte through which lithium ions can pass, and a separator to keep the cathode and anode separated. In general, the cathode, anode, separator, and electrolyte make up the four major components of a lithium-ion battery.

Cathode

In a lithium-ion battery, lithium ions enter into the cathode, which can be thought of like a house for lithium ions. Lithium is a perfect cathode material since it tends to lose electrons and turn into a positive ion. However, since elemental lithium is unstable, lithium oxide, a combination of lithium and oxygen, is used instead.

The cathode determines the capacity and voltage of a battery, which are the critical components of battery performance. Battery capacity improves as the lithium proportion increases. The voltage is determined by the potential difference between the electrodes. Therefore, the potential value due to the structure of the cathode and anode influences voltage. Recently, as the demand for high-performance cathode materials increases, various cathode materials like NCA (nickel/cobalt/aluminum) and NCMA (nickel/cobalt/manganese/aluminum) are under development.

Anode

Anode materials store and release lithium ions from the cathode, allowing current to flow through an external circuit. When the battery is charged, lithium ions are in the anode. When the anode and cathode are connected with a conducting wire, lithium ions move from the anode to the cathode via the electrolyte, while the electron separated from the lithium ions move along the wire, generating electricity. You can think of it as lithium ions leaving home and generating electricity while working.

Graphite can store many ions and is mainly used for anode materials. However, as the process of storing and releasing lithium ions is repeated, the structure of graphite changes, and the number of ions that can be stored decreases, reducing battery life. That is why the next-generation anode materials, such as silicon with a large capacity and can accelerate charging, are currently being developed.

Electrolyte

Electrolyte is a medium that helps lithium ions move between the cathode and anode inside the battery. It can be thought of as a form of transportation that lithium ions take to commute to work. The electrolyte must have high ionic conductivity for the smooth movement of lithium ions, as well as high electrochemical stability and high flash point for safety. Also, it is necessary to prevent the electrons from entering the electrolyte and make them only move along the external conducting wire.

Currently, liquid electrolytes are widely used for this purpose. However, research is now being carried out on solid or gel-type electrolytes with better safety and performance.

Separator

As it is essential to completely separate work from home to achieve a good work-life balance, a separator prevents the cathode and anode from having physical contact. Tiny pores on the separator allow lithium ions to move. In other words, the separator blocks the contact between the two electrodes but allows ions to move through.

The separator needs to have high electrical insulation and thermal stability for safety, and it must also automatically block the movement of ions at a temperature above a certain level. Currently, polyethylene (PE) and polypropylene (PP) are widely used as separators. A study is currently being conducted on making the separator thinner to miniaturize the battery.

So far, we have looked at the four main components of a lithium-ion battery and how they work. Lithium-ion batteries have made our lives as convenient as it is today, and yet, even at this moment, more studies are being carried out to overcome their limitations. LG Energy Solution is leading the industry and is heading the development of next-generation batteries. On held in April , LG Energy Solution announced plans to commercialize lithium-sulfur batteries in and all-solid-state batteries between and .

In September , LG Energy Solution, through a joint study with the University of California San Diego (UCSD), announced that it had overcome the technical limitations of the all-solid-state battery, which could only be charged above 60℃. The company has developed a long-life all-solid-state battery technology that can be charged at room temperature (25℃) at a fast rate. The technological breakthrough was recognized and published in the renowned scientific journal, Science. Even now, many people are striving to commercialize next-generation batteries, and we are, in fact, a step closer to the future without even noticing it.

Want more information on LED emergency driver power supply? Feel free to contact us.