The Benefits of a Lithium Battery
Pound for pound, lithium batteries pack more energy than other rechargeable battery types. They’re found in a variety of products, including power tools and digital cameras.
These batteries can also pose a fire risk when improperly disposed of, especially in homes and recycling bins. They contain lithium metal, a porous separator and an electrolyte that conducts lithium ions during charging and discharging.
1. Energy Density
Pound for pound lithium batteries have one of the highest energy densities of any rechargeable battery. High energy density is important because it allows for the use of smaller, lighter batteries that emit power for longer periods of time. This is especially helpful in applications such as electric vehicles and handheld devices where space and weight are a concern.
Lithium batteries come in a variety of shapes and sizes, with some containing an aluminum current collector and others using a graphite one. They’re often housed in a metal case with a pressure-sensitive vent hole. This is a safety feature that prevents the battery from building up too much pressure and exploding.
Lithium-ion cell chemistry has a large number of variations, but the most common is lithium iron phosphate (LiFePO4) with a graphite anode. Other chemistries such as lithium nickel cobalt oxide and lithium manganese cobalt aluminum oxide offer lower energy densities but better safety characteristics. Energy densities vary across cell type, thickness and conditions, but most show a monotonic decrease with increasing thickness.
2. Lightweight
When it comes to batteries, weight is an important factor. No one wants to haul around a battery that isn’t going to give them the power they need. For this reason, lithium lithium battery batteries are a very light choice for many applications.
Button-cell, coin and other single-use lithium batteries use lithium metal as their primary component. They are used in a variety of products, including hearing aids, keyless car remotes and medical devices. Because of their small size, they can be a swallowing hazard for young children and should be stored away from them. They are also prone to spontaneously combusting if they are accidentally punctured or crushed.
Lithium-ion batteries contain a positive electrode made of lithium cobalt oxide and a negative electrode made of graphite. The lithium ions are transferred between the electrodes by a process called intercalation. During charging, the anode releases lithium ions to the cathode and vice versa during discharge. This allows the battery to quickly provide high-quality currents. A protective circuit is built into every lithium-ion battery pack to ensure safe operation. It prevents the cell voltage from getting too high during charge or too low during discharge and protects against overcharge and overheating.
3. Long Lifespan
Lithium batteries are designed to provide long battery life. They are capable of hundreds of charge/discharge cycles, but they will eventually reach the end of their life. This is because the lithium ions inside of them are moving in and out of their respective electrodes, creating a small electrical current (voltage times energy) which depletes the battery’s capacity over time.
The lithium ions that move in and out of the electrodes are also creating chemical reactions that result in the formation of an electrolyte film on the negative electrode. The film grows thicker, reduces cycling capacity and creates gases that increase the cell’s internal resistance. This process is called “aging” or simply “wearing out.”
Fortunately, there are ways to prolong your battery’s lifespan and ensure that you get the maximum longevity from it. These include avoiding heat, keeping the battery’s stamped date in mind, and only using it as instructed. In addition, smart charging systems can monitor a battery’s temperature, state of charge and voltage to regulate the current it receives. This helps extend its lifespan by preventing overcharging.
4. Low Self-Discharge Rate
A battery’s self-discharge rate is the amount of power it loses over time when not in use. It affects how often you should charge your lithium battery and it can impact how long your battery will last.
Lithium batteries typically have a low self-discharge rate. However, that can be different depending on the temperature of your battery and how long you are using it.
Battery performance is affected by temperature because it impacts the reversible capacity degradation of the battery. High temperatures cause the electrolyte salt to be oxidized. This can result in metallic lithium plating on the anode. This plating is a serious concern because it can lead to an internal short circuit on recharge.
This is because the metallic lithium can pierce through the separator sheet and then lithium battery conduct current between the negative and positive electrodes. This causes the battery to heat up and potentially explode. To prevent this from happening, it’s important to keep the temperature of your battery as low as possible.
5. No Venting Gases
Although lithium batteries are quite safe, a battery pack can become overcharged, which causes the cells to vent. When this happens, the organic solvent used as an electrolyte can be ignited by heat and cause a fire. The fire can then spread to the other cells in the battery and cause a larger fire that could affect the entire pack.
To prevent this, most packs are built with a protection circuit that limits the peak voltage of each cell during charge and prevents the cells from dropping too low on discharge. The protection circuit also monitors the temperature of each cell to ensure that it does not get too hot.
In addition to the cell failure detection, gas sensors are used for fault detection. Gas sensors detect the presence of early volatile organic compounds (VOCs) in the first vent-gas and the carbon monoxide (CO) found in the vent-gas during cell thermal runaway. The flammability range of the vent-gas is affected by the state of charge (SOC) and the initial temperature and pressure. The sensor can quickly react to the change in flammability range to alert the user of a potential problem.
