Lithium-ion batteries are integral to powering a wide range of devices, from small gadgets to large construction tools. As such, understanding the difference between the two common types of lithium-ion cells, 21700 and 18650, is essential. These designations primarily refer to the physical size of the cells. The 18650 cell has a diameter of 18 millimeters and a length of 65 millimeters, while the 21700 cell is 21 millimeters in diameter and 70 millimeters long. This size difference may seem minor, but it results in a 47% increase in volume, allowing the 21700 to hold significantly more energy.
The increased size of the 21700 cell provides more space for energy-storing components—namely the anode, cathode, and electrolyte. This translates into a higher energy density, which is crucial for devices that require long-lasting power. For instance, batteries used in power tools that operate with 18650 cells typically range from 1 to 3 amp hours per cell. However, cells at the higher end of this range have experienced issues, with 2.5 amp hours per cell being about the maximum feasible capacity without sacrificing reliability.
On the other hand, 21700 cells start at around 3 amp hours and can go up to 4 amp hours per cell. This capacity increase is particularly beneficial in the construction industry, where tools powered by 21700 cells. Furthermore, these batteries have improved cooling mechanisms and materials that reduce electrical resistance, enhancing overall power delivery.
This advancement in battery technology has expanded the possibilities for cordless tools, enabling more powerful and efficient tools traditionally tied to corded or gas-powered sources. Now, heavy-duty equipment like table saws, 12-inch miter saws, and 2-inch SDS max rotary hammers are becoming cordless. The landscaping and lawn care industry, along with sectors traditionally dominated by gas-powered machinery, are also benefiting from these powerful battery options.
FAQs
Q1: Why are 21700 cells considered better than 18650 cells for power tools?
A1: The 21700 cells offer a larger volume, which allows for a higher capacity and energy density. This means power tools equipped with 21700 batteries can run longer and deliver more power, making them more efficient for professional use where performance and runtime are critical.
Q2: How do the improvements in 21700 battery technology impact tool performance?
A2: The increased energy capacity and reduced electrical resistance in 21700 batteries allow for higher power output and longer run times. These improvements enhance the overall performance of power tools, enabling more demanding applications that were previously not possible with battery-powered tools.
Q3: What future advancements can we expect in cordless tool technology due to 21700 batteries?
A3: As 21700 battery technology continues to evolve, we can expect to see further advancements in cordless tool capabilities, including more robust power delivery and longer battery life. Additionally, the range of tools and equipment that can effectively transition to cordless will expand, likely including more heavy-duty machinery and traditionally gas-powered equipment.