Skip to main content

Charging and Discharging Li-ion Cells / Batteries Systems

Find out how to extend your Battery Systems using the best charging methods

When charging and discharging batteries a chemical reaction occurs, but with lithium ions there is an exception. Scientists speak of the energies flowing into and out of the battery as part of the movement of ions between the anode and the cathode. If scientists were right, according to this statement the battery would live forever but it is not. They blame the fading of the trapped ions, but as with all battery systems, internal corrosion and other degenerative effects also known as parasitic reactions on the electrolyte and electrodes play a role.

The lithium ion charger is a voltage limiting device that has similarities to the lead-acid battery system. Differences from Li-ion are found in higher voltage per cell, tighter voltage tolerances, and the absence of drip or float charge at full charge. While lead acid offers some flexibility in terms of cut-off voltage, Li-ion manufacturers are very decisive in the correct setting because Li-ion cannot accept any overload. The so-called "miracle charger" that promises to extend Battery Systems life and increase extra capacity does not exist. The Li-ion system is a "clean" system and only takes what it can absorb.

Charging cobalt batteries mixed with Li-ion

Specifically, we refer to Li-ion batteries made with the traditional cathode materials of cobalt, nickel, manganese and aluminum, charging typically at 4.20V / cell. Tolerance is +/- 50mV / cell. Some nickel-based varieties are charged at 4.10V / per cell; The high capacity Li-ion can go to 4.30V / per cell. Increasing the voltage also increases the capacity, but going beyond the specification can overcharge the battery. Protection circuits incorporated in the package do not allow exceeding the set voltage.

the variation of voltage and current when lithium ion passes through the current phases. Full load is reached when the current drops to between 3% and 5% of the Ah rating.

The temperature oscillation in the charge of a power cell is between 0.5C and 1C and the full charge time is approximately 2-3 hours. The manufacturers of these cells recommend charging at 0.8C or lower to prolong battery life. Most power cells can take a more powerful charger. The charging efficiency is around 99% and the cell stays cool during charging.

Some Li-ion batteries may experience a temperature rise of approximately 5ºC when fully charged. Discontinue use of the battery or charger if the temperature rises above 10ºC under moderate charging speeds.

Full charge occurs when the battery reaches the voltage threshold and the current drops to 3% of the rated current. A Battery Systems is also considered fully charged if the levels turn off and cannot drop any further. An increase in charge current does not advance a full charge. Although the battery reaches peak voltage faster, as a result the saturation charge will take longer. With higher current, Stage 1 is shorter, but saturation during Stage 2 will take longer. A high current charge, however, will quickly fill the battery to approximately 70%.

A Li-ion battery does not need to be fully charged as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge it because high voltage will overload the Battery Systems. Choosing a lower voltage threshold or eliminating saturation charging entirely prolongs battery life, but this reduces runtime. Chargers for other products go to maximum capacity and cannot be adjusted; so the useful life of the product itself is perceived as less important.

Some low-cost consumer chargers can use the simplified "charge and run" method that charges a lithium-ion battery in one hour or less without going to Stage 2 saturation charging. "Ready" appears when the Battery reaches threshold voltage in Stage 1. The state of charge (SoC) at this point is approximately 85%, a level that may be sufficient for many users. Some industrial chargers purposely set the charge voltage threshold lower to prolong battery life. Table 2 illustrates the estimated capacities when charged at different voltage thresholds with and without saturation charging.

Comments

Popular posts from this blog

Bathroom renovation principles

Professional builders and designers classify bathrooms as "complex" spaces, the design of which has many nuances. Bathroom renovation design should combine aesthetics and functionality.  In the morning they take an invigorating shower, in the evening - a relaxing bath.  The finished bathroom design project should take into account convenience and beauty. The basic idea of ​​the new arrangement and design should be developed before renovation.  Of course, repairing a spacious room is easier.  You do not need to think long about the placement of plumbing, furniture and household items.  It's more difficult with a small bathroom. When creating a  Bathroom renovation  design project, do not limit yourself to choosing a style.  The bathroom can be in harmony with other rooms or be separate.  The optimal design will help hide all the flaws.  When developing a concept, it is important to take into account all the details: from lighting the ceiling to decorative elements. The fi

Floor Types from Around the World with tilling

Do you feel bored with the appearance of the floor that seems like all? Which type of floor is most interesting? Rather than curious, this time we will provide a review of several types of floors For that, let's just watch it! Flooring tilling is a general term for a permanent undercover cover. Unlike the 'floor coverings' which describe each final material that is applied on the floor structure to provide a surface for walking.The two terms are used interchangeably but floor covering refers more to loose material. The floor that is under the floor is usually called a subfloor, this is useful to provide support for the upper floor so that it is always strong to support the load.Subfloors that are under the floor (underground) or ground floor tilling in buildings without basements usually have very strong concrete subfloors. Wood is one of everyone's favorite flooring types. Wooden floors provide a combination of beauty and appeal that is rarely found in other types of

HOW TO RENOVATE A FLOOR SANDING?

Are you thinking about replacing an old wooden floor?  When does a wooden floor need renovation, when renovation and when is proper cleaning enough?  How to know and how to cope?  Long-used wooden floors in old buildings due to  moisture, due to poor installation, incorrect maintenance or simply old age  lose their original appearance and good utility properties.  Usually, users are sorry to tear out and replace the entire  Floor Sanding  so they are looking for ways to gently renovate it, which could save old wood.  Sometimes it works, other times it's too late to save. RECONSTRUCTION By floor reconstruction is meant a complete  renovation, including the subsoil  .  How do we know if such a radical intervention is needed or not? The key is to judge whether the subsoil under the roofing is in order.  It's not easy without pulling out part of the floor and looking under it.  As a first step, however, we can perform  our own self-diagnosis  . Clear the whole room, move out the fu