What’s Inside a Lithium-Ion Car Battery?

Inside an EV battery, you’ll find an array of slightly mushy lithium-ion electrochemical cells. Each cell has a positive cathode and negative graphite anode, separated by a micro-permeable separator and immersed in a liquid solution called an electrolyte.

Lithium-ion batteries are used in consumer electronics and electric cars because they offer high energy density, long lifespans and reliability. Let’s explore how they achieve these qualities.

High Energy Density

A battery’s energy density is the amount of electrical power it can hold per unit of volume or weight. It is a crucial measure for any appliance that needs to pack in as much charge as possible, such as electric vehicles (EVs).

A lithium-ion car battery is a densely packed collection of hundreds or even thousands of slightly mushy electrochemical cells shaped like cylinders or pouches. Each cell consists of a positive, metal oxide-based cathode and a negative, graphite-based anode immersed in a conductive ionic liquid called the electrolyte. Each electrode lets lithium ions pass in and out through its structure via a process called intercalation or extraction. Electrons gathered in the negative electrode during discharging travel to the positive electrode via an external circuit, and this electrical energy is stored chemically as a charge.

To recharge, an external electrical power source applies a voltage higher than the battery’s own through the cells, forcing electrons to flow from the positive to the negative electrode. This also makes the positive electrode’s porous material receptive to lithium ions, which can migrate through the electrolyte and enter its structure (called intercalation).

The battery stores the charge in an arrangement of tightly packed lithium atoms that form an intercalated solid. This is what gives the battery its high energy density. Lithium ion batteries currently deliver a energy density of 200-300 Wh/kg, and technology gains could see them double to 500Wh/kg by the 2030s and treble to 750Wh/kg by the 2040s.

Long Lifespan

A lithium-ion battery has an average lifespan of 10 to 20 years. That’s longer than nickel cadmium and nickel-metal hydride batteries, which had been the technology of choice in electric vehicles until the advent of lithium-ion.

These lithium-ion batteries’ long lifespan is largely due to their ability lithium ion car battery to endure hundreds, and sometimes thousands, of charge cycles. It is also because they are more energy-dense than their predecessors, so that they can power a car for greater distances on a single charge.

However, the materials used in lithium-ion batteries are not without an eco-footprint. Mining cobalt and lithium requires a great deal of chemicals, water, and heat to process into the components that make up the battery. And the fact that this energy has to come from fossil fuels (along with other pollutants) further adds to the environmental cost of these batteries.

For those reasons, EV owners are advised to follow some routine dos and don’ts in order to maximize their battery lifespan. For example, EV drivers should park their car in shaded areas and keep the maximum battery state of charge below 100%. This is because the battery’s degradation processes are accelerated best car battery brand by high temperatures and full-charge conditions. In addition, it is advisable to drain the battery down to 80% on a regular basis in order to minimise degradation.

High Rechargeability

An important feature of lithium ion batteries is their ability to be recharged many times over the course of their lifespan. This is a key attribute that allows them to provide energy for cars at a higher capacity than other battery types, and to also offer an extended lifespan without having to be replaced as often.

When a battery is charged, the liquid electrolyte shuttles lithium ions from the cathode (graphite) to the anode (a lithium-containing oxide), which helps it produce electricity. The amount of electricity produced is measured in watt-hours, or kWh. The number of cells, their size and how they are arranged determines the voltage delivered by the battery and its capacity.

Lithium-ion batteries are extremely durable and have great power density. They can withstand vibration, shock and extreme temperatures better than lead-acid batteries. They can even be dismantled for recycling. However, it is important to understand the limits of a lithium ion battery.

When a battery is not maintained correctly, it can quickly degrade. This can result in individual cell failure or overheating. It is important to use a battery charger like the CTEK Lithium US Charger to help your vehicle perform at its best and maintain the health of your battery. The patented eight-step program tests the condition of the battery, charges and maintains it to prolong its lifespan.

Low Weight

While the energy density of lithium ion batteries is very impressive, their weight remains a concern for car buyers. A battery’s weight can affect the vehicle’s handling and performance, especially when it comes to accelerating and top speed.

Fortunately, manufacturers are working hard to bring down the weight of lithium batteries to help improve fuel efficiency and range. The best way to do this is by increasing the voltage of a battery pack. This will allow the battery to provide more electric current, which is needed to power an EV’s motor. However, higher voltage also means more cells and a larger battery, which can lead to a heavier battery.

The most advanced lithium ion batteries currently used in EVs and PHEVs have a cell voltage of around 3.7 volts per cell. This allows them to produce a significant amount of power and torque, which helps the vehicles accelerate quickly and maintain a high top speed.

Considering that the specific energy of gasoline is about 12 kWh/kg, this suggests that lithium batteries are able to hold a similar amount of power in a smaller volume, making them a great choice for EVs. For this reason, the California state government has created a Battery Recycling Advisory Group to oversee policies regarding the collection, processing and recycling of lithium batteries sold with vehicles in the state.