Tag Archives: Li-Ion

Buck battery charger handles multiple chemistries

4015

by Susan Nordyk @ edn.com:

The LTC4015 synchronous step-down battery charger controller from Linear Technology offers charge current of up to 20 A, multiple-chemistry operation, and onboard digital telemetry. The controller transfers power from a variety of input sources, such as wall adapters and solar panels, to a Li-Ion polymer, LiFePO4, or lead-acid battery stack with system load up to 35 V.

Operating over an input voltage range of 4.5 V to 35 V, the LTC4015 provides ±5% charge-current regulation up to 20 A and ±0.5% charge-voltage regulation. While a host microcontroller is required to access the most advanced features of the LTC4015, the use of an I2C port is optional.

Buck battery charger handles multiple chemistries – [Link]

How to make a USB Li-Ion charger

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by Robert Gawron @ robertgawron.blogspot.com:

Li-ion cells become more and more popular due to their capacity and reasonable prices. In this entry I will present how to build a simple li-ion battery charger based on MCP73831 chip. It’s a quite useful device for DYI projects,in addition its cost is only around 1,5 euro.

The device uses USB port as a power supply (mini-USB connector). I use the standard gold-pins as an output socket. There’re three of them, but only two are used (looking on the image, counting from top: V+, V-). I will design my li-ion based devices in the same way (same socket, but female), then if I will connect it in the incorrect direction (rotated 180 degrees) they won’t be damaged (V- connected to V-, but V+ connected to n/c pin) – simple way to avoid plugging in an incorrect way.

How to make a USB Li-Ion charger – [Link]

Research Points the way to Safer Lithium Batteries

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by Martin Cooke @ elektormagazine.com:

A paper published in the June 17th edition of Nature Communications describes how the addition of two chemicals to the electrolyte of lithium metal batteries can prevent the formation of dendrites. These are needles of lithium which grow in the battery and eventually puncture the barrier between the two battery halves. Their formation can cause short circuits in the battery which leads to overheating and sometimes combustion.

According to the paper this breakthrough could help remove a major barrier to the future development of lithium-sulfur and lithium-air batteries. These promising new battery technologies could store up to 10 times more energy per weight than batteries in use today in consumer electronics and electric cars.

Research Points the way to Safer Lithium Batteries – [Link]

Samsung Researchers Nearly Double Lithium-ion Battery Capacity

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by GardenState @ element14.com:

Silicon is receiving considerable attention as an active material for next- generation lithium-ion battery anodes because of its gravimetric capacity–a measure in mAh/g of the total charge capacity stored by the cell or battery, per gram of the battery’s weight.

Unfortunately, the large volume change of silicon during charge–discharge cycles has in the past weakened its competitiveness. Recently, however, a research group from Samsung reported in the publication Nature Communications that using direct graphene growth over silicon nanoparticles without silicon carbide formation resulted in a near doubling of run-time by expanding energy density– the amount of stored power in a given area — to 1.8 times that of current batteries.

Samsung Researchers Nearly Double Lithium-ion Battery Capacity – [Link]

IC manages battery-backup systems

4040

Housed in a low-profile 24-pin QFN package, the LTC4040 from Linear Technology is a 2.5-A lithium-battery–backup power-management system for 3.5-V to 5-V supply rails that must be kept active during a main power failure. The device uses an on-chip bidirectional synchronous converter to provide high-efficiency battery charging, as well as high-current, high-efficiency backup power.

When external power is available, the LTC4040 operates as a step-down battery charger for single-cell lithium ion or lithium iron phosphate batteries, while giving preference to the system load. When the input supply drops below the adjustable power-fail-input threshold, the LTC4040 operates as a step-up regulator capable of delivering up to 2.5 A to the system output from the backup battery. In the event of a power failure, the part provides reverse blocking and a seamless switchover between input power and backup power.

IC manages battery-backup systems – [Link]

Charging batteries rapidly and safely

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by Steve Taranovich @ edn.com

Any hobbyist can charge a battery quickly, but can you do it without an explosion, excessive heating or major degradation in battery cycle life?

Well many companies have managed fast charging techniques that typically use specialized algorithms. These algorithms take into account the chemistry of the battery and some sort of non-standard charging rate curve. Many device manufacturers and wireless operators are now providing a minimum two-year warranty on smart phone devices setting 800 cycles as the battery cycle life of the battery.

Charging batteries rapidly and safely – [Link]

Single-cell 5-A Li-Ion battery charger with MaxCharge™ technology

 

BQ25890

TI’s new bq25890, bq25892, and bq25895 5A chargers with TI’s MaxCharge™ technology charge your mobile device faster while keeping your device cooler. The switch-mode chargers can charge a 1-S Li-Ion cell to 80% capacity in 30 minutes, while traditional devices only reach 30%. The I2C-controlled chargers’ high efficiency and thermal management result in the fastest, safest and coolest charging capability.

Key features and benefits

  • Fast charging to high capacity battery with up to 5A high charging current
  • Optimized for high voltage input: >91% charging efficiency at 3A with 9V input
  • Innovative Input Current Optimizer (ICO) to maximize input power without overloading adapter
  • Resistance compensation from charger output to cell terminal to enhance power delivery to battery
  • Integrated ADC for charging system monitoring

Single-cell 5-A Li-Ion battery charger with MaxCharge™ technology – [Link]

Intelligent 4-Cell Lithium Battery Management with CAN/LIN Interface

This design is a battery management circuit, which involves the use of CAN/LIN interface. The system addresses the matter about managing rechargeable batteries. This design features an 8-output hardware configurable, high side/low switch with 16-bit serial input control using the serial peripheral interface (SPI). Two of the outputs are directly controlled using a microcontroller which are applicable in pulse-width modulation. The design also features high-speed CAN interface that is use to convert digital protocol information into an analog CAN communication.

The RD9Z1-638-4Li reference design is a Battery Management System (BMS) for 4-Cell Li-Ion battery applications featuring the MM9Z1_638 Battery Sensor Module. The RD9Z1-638-4Li is built to demonstrate the product capabilities in a 4-cell Li-Ion application where high EMC performance is required to obtain high accuracy measurements on key battery parameters. The board features an 8-pin standalone CAN transceiver to interface with others modules. Very high EMC robustness and performances are achieved by the Freescale MC33901 CAN High-Speed Transceiver. For cell balancing function and general purpose switches, the board features the Freescale MC33879 Configurable Octal Serial Switch.

The design is useful to automotive applications such as engine management, climate controls, communications and safety systems. The circuits function is suitable for a hybrid electric vehicle which monitors the condition of individual cells which make up the battery and maintains all the cells within the operating limits. It also provides information on the state of charge (SOC) and state of health (SOH) of the battery.

Intelligent 4-Cell Lithium Battery Management with CAN/LIN Interface – [Link]

With MCP73831 you’ll charge lithium cells easily and safely

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And it can be added that also simply and cheaply. MCP73831 from company Microchip is „all-in-one“ solution for charging a single Li-ion/Li-Po cell.

Li-Ion a Li-Polymer cells are becoming a No.1 choice for many applications, where they persuade by high energy density, low weight, low self-discharge and for majority of applications also by their favorable flat shape (Li-Po). Their price is also affordable (in regard to their properties) and so there´s usually only one “difficulty” – to solve charging, or more exactly – overall management of these cells. Basic principles were highlighted to you in our article “Try the most favourite types of batteries”. To reach a maximum cell lifetime, it´s also advisable to use initial (preconditioning) slow charging and also important is a proper charging termination as well as repeated recharging after reaching a certain degree of discharge.It´s obvious, that to construct such a circuit from discrete components would be possible, but impractical, bulky and expensive. That´s why there are various charging controllers on the market and in many cases a single chip solution is an ideal solution. This is also a case of MCP73831 chip – a fully integrated linear charging controller. If you use only a single cell and maximum charging current of 500mA is sufficient for you, then MCP73831 will meet all requirements for a quality and safe recharging solution. MCP73831 has integrated output (FET) transistor, current sensing and reverse discharge protection.

Charging current can be easily adjusted by a single resistor, what´s also associated with other parameters like preconditioning current and charging termination. MCP73831 also contains a thermal regulation, which decreases output current in case of increased chip temperature (for example because of higher ambient temperature).

MCP7383x is available in four versions with factory-set regulation (max. charging) voltage. In our store can be found “the safest” first version with 4.20V regulation voltage – MCP73831T-2ATI/OT. In datasheet (p. 25) we can also read that this is the “AT“ version, which starts repeated charging at 94% Vreg (i.e. at approx. 3.95V), in a SOT23-5 package. Supply voltage can be in a range of 3.75-6V, while in respect to a thermal stress of a chip it´s better to supply it by a voltage close to max. output voltage (4,20V).

The chip can be easily supplied by a standard 5V voltage, but in cases of increased risk of overheating (operation at higher ambient temperatures, densely populated PCB,…), a common Si diode in series can be helpful. This will decrease supply voltage in 0.6-0.7V (and takes a portion of thermal loss on itself).
Charging status can be found at the “Charge status output” pin, which can drive an indication LED or can be connected to a host microcontroller.

With MCP73831 you’ll charge lithium cells easily and safely – [Link]