Cells and batteries are essential electrochemical devices that convert chemical energy into electrical energy. They are the power sources behind various electronic devices and systems.
A cell is a single electrochemical unit that converts chemical energy into electrical energy. It consists of two electrodes, an anode and a cathode, which are separated by an electrolyte, a substance that facilitates the flow of ions between the electrodes. When a cell is connected to a circuit, the chemical energy stored in the cell is converted into electrical energy, allowing the current to flow through the circuit.
On the other hand, a battery is a collection of two or more cells connected together. Unlike cells, batteries are designed to provide a larger amount of electrical energy and can be used in a wider range of applications. Batteries can be classified into two categories: primary and secondary. Primary batteries are non-rechargeable and are designed to be used once and then discarded, whereas secondary batteries are rechargeable and can be reused multiple times.
These are common differences between cells and batteries below:
| Cells | Batteries |
| A cell is a single electrochemical unit that converts chemical energy into electrical energy, typically consisting of an anode and a cathode. | A battery is a collection of two or more cells interconnected to provide a more substantial and longer-lasting power source. Batteries can be either primary (non-rechargeable) or secondary (rechargeable). |
| Cells are usually non-rechargeable (primary), designed for single use, and their chemical reactions are not easily reversible. | Batteries can be rechargeable (secondary) and allow for the reversal of chemical reactions, enabling multiple charge-discharge cycles and extended use. |
| Cells are typically standalone units, often encased in metal, with their anode, cathode, electrolyte, and casing. | Batteries consist of multiple cells connected together, either in series or parallel, to achieve higher voltage, capacity, and energy output. |
| Each cell contains its anode (negative electrode) and cathode (positive electrode) to facilitate electrochemical reactions. | Each cell within the battery maintains its anode and cathode, collectively contributing to the overall battery's performance. |
| Cells are employed in smaller-scale devices, such as watches, calculators, and hearing aids, where compact size is essential. | Batteries are used in larger devices, such as laptops, cars, uninterruptible power supplies (UPS), and other applications requiring higher power capacity. |
| Cells generally produce lower voltages, typically suitable for low-power and small devices. | Batteries offer the flexibility of achieving higher voltage by combining multiple cells, making them suitable for a wide range of applications. |
| Common examples of cells include button cells (e.g., watch batteries), AA cells, and coin cells. | Batteries encompass a wide range, including car batteries, laptop batteries, and rechargeable battery packs. |
| Cells are often used in portable electronic devices, thanks to their compact size and lightweight nature. | Batteries, due to their assembly of multiple cells, are less portable and typically used in larger devices or applications. |
| Cells are generally cost-effective, making them suitable for disposable devices and low-cost applications. | Batteries can be more expensive, particularly when requiring larger capacities, due to the assembly of multiple cells and their increased power output. |
| Cells find applications in devices like remote controls, watches, hearing aids, and small consumer electronics. | Batteries are used in diverse applications, including electric vehicles (EVs), backup power systems, laptops, and energy storage for renewable sources. |
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Types of Cells
These are some different types of cells.
Primary cells
These are disposable batteries that cannot be recharged and must be replaced when they run out of energy. They are commonly used in low-drain devices such as remote controls, clocks, and radios.
Secondary cells
These are rechargeable batteries that can be reused multiple times. They are commonly used in high-drain devices such as mobile phones, laptops, and electric vehicles.
Lead-acid cells
These are the oldest type of rechargeable batteries and are widely used in cars, trucks, and backup power systems. They have a relatively low self-discharge rate and are relatively inexpensive.
Nickel-cadmium (Ni-Cd) cells
These were widely used in portable devices, but have largely been replaced by nickel-metal hydride (NiMH) and lithium-ion (Li-ion) batteries. They have a high self-discharge rate and contain toxic heavy metals.
Nickel-metal hydride (NiMH) cells
These are commonly used in hybrid and electric vehicles, as well as in portable devices. They have a lower self-discharge rate than Ni-Cd batteries and are less toxic.
Lithium-ion (Li-ion) cells
These are widely used in portable electronics, electric vehicles, and renewable energy systems. They have a low self-discharge rate and a high energy density, making them ideal for high-power applications.
Lithium-iron phosphate (LiFePO4) cells
These are similar to Li-ion batteries but have a slightly lower energy density. They are used in applications where safety and lifecycle are important, such as in electric vehicles and renewable energy systems.
Construction of Cells
Metal Case
Cells are typically housed in a metal casing, which serves as a protective shell, isolating the internal components from the external environment. The casing is essential for maintaining the structural integrity of the cell.
Electrolyte
An integral component of a cell, the electrolyte is a substance that facilitates the flow of ions between the two electrodes (anode and cathode). The choice of electrolyte can vary, and it can be liquid, gel, or solid, depending on the type of cell.
Two Electrodes
The anode is the negative electrode, where oxidation (loss of electrons) occurs during discharge. It releases electrons into the external circuit. Whereas, the cathode is the positive electrode, where reduction (gain of electrons) takes place during discharge. It receives electrons from the external circuit.
Types of Batteries
These are common types of batteries.
Flooded lead acid battery (FLAB)
This type of battery is commonly used in applications such as backup power systems, off-grid solar systems, and electric vehicles.
Deep cycle battery
This type of battery is designed for applications that require frequent deep discharges, such as sailboats, recreational vehicles, and electric vehicles.
Traction battery
This type of battery is used in electric vehicles, golf carts, and other electric vehicles.
Stationary battery
This type of battery is used in stationary energy storage applications, such as grid-scale energy storage.
Consumer battery
This type of battery is used in portable devices, such as mobile phones, laptops, and cameras.
Electric vehicle battery
This type of battery is used in electric vehicles, such as electric cars, buses, and bicycles.
Renewable energy battery
This type of battery is used in renewable energy systems, such as solar and wind turbines.
Backup battery
This type of battery is used in backup power systems, uninterruptible power supplies, and standby power systems.
Construction of Batteries
Collection of Cells
Batteries are created by connecting two or more cells in series or parallel. The combination of multiple cells within a single unit increases the overall voltage, capacity, and energy output. This interconnected arrangement allows batteries to provide a stable and more practical power supply.
Anode and Cathode for Each Cell
Each cell within a battery retains its anode and cathode. The electrodes in all cells work collectively to produce the total battery output.
Applications of Cells and Batteries
Cells and batteries are integral power sources for various applications, enabling portability, reliability, and energy storage in different industries:
Cells and batteries power a vast array of portable devices, including smartphones, laptops, tablets, digital cameras, and handheld gaming consoles. Their compact size and energy density make them ideal for these applications.
Lithium-ion and other advanced batteries drive electric cars, buses, and bikes. They offer the energy density required for extended driving ranges and are central to reducing fossil fuel dependency.
Cells and batteries are essential components of energy storage systems for renewable energy sources like solar and wind. They store excess energy generated during periods of high supply and release it during demand spikes or when renewable sources are inactive.
Implantable medical devices such as pacemakers and hearing aids rely on small, long-lasting cells to ensure uninterrupted operation. These batteries must provide a stable power supply for critical healthcare devices.
In industrial settings, batteries are employed for backup power in case of grid failures, as well as for autonomy in mobile equipment like forklifts and robotics.
The military relies on batteries to power various equipment, including communication devices, drones, GPS systems, night-vision goggles, and missile systems. High-performance batteries are essential for mission success.
Beyond smartphones and laptops, cells and batteries are used in everyday consumer electronics such as remote controls, toys, flashlights, and cordless phones.
Batteries are crucial for aviation and aerospace applications, powering avionics, drones, satellites, and spacecraft. High-performance batteries are essential for the reliability and safety of these systems.
Cells and batteries are used to store excess energy from renewable sources such as wind and solar for use during periods of low energy production or high demand, helping stabilize the grid.
Cells and batteries are being employed in emerging technologies like wearable devices, electric bikes, and advanced robotics, expanding their applications into new frontiers.
Key Takeaways
Concepts Berg
What is the difference between a cell and a battery?
A cell is a single electrochemical unit that converts chemical energy into electrical energy, consisting of an anode and a cathode. A battery, on the other hand, is a collection of two or more cells interconnected. It can be primary (non-rechargeable) or secondary (rechargeable).
How are cells and batteries constructed?
Cells typically have a metal casing, an electrolyte, and two electrodes (anode and cathode). Batteries are constructed by connecting multiple cells, each with its anode and cathode, in series or parallel, depending on the required voltage and capacity.
What are some common types of cells and batteries?
Common types of cells include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries. Batteries can vary based on the application’s requirements and voltage needs.
What is the role of the electrolyte in cells and batteries?
The electrolyte in cells and batteries facilitates the flow of ions between the anode and cathode, allowing the electrochemical reactions that convert chemical energy into electrical
energy.
Why are primary batteries non-rechargeable, while secondary batteries are rechargeable?
Primary batteries are designed for single use, and their chemical reactions are not easily reversible. Secondary batteries, being rechargeable, can reverse these chemical reactions, allowing multiple charge-discharge cycles.
What are the applications of cells and batteries in portable electronics?
Cells and batteries power devices like smartphones, laptops, digital cameras, and portable gaming consoles, providing them with the necessary energy for portability and usage on the go.
How are cells and batteries used in electric vehicles (EVs)?
Electric vehicles, including cars, buses, and bikes, use high-capacity lithium-ion batteries to store electrical energy and power electric motors, enabling emission-free transportation.
What is the significance of cells and batteries in renewable energy storage?
Cells and batteries are crucial for storing excess energy generated from renewable sources like solar panels and wind turbines. They release stored energy during peak demand or when renewable sources are inactive, enhancing grid stability.
In what way do cells and batteries support medical devices?
Cells and batteries power medical devices such as pacemakers and hearing aids, ensuring these devices continue to function reliably over extended periods.
What are the emerging applications for cells and batteries?
Cells and batteries are finding new applications in emerging technologies, including wearable devices, electric bikes, advanced robotics, and energy-efficient lighting, expanding their usage into innovative fields.
