Tag Archives: Battery

Carrageenan, a seaweed derivative, can stabilize lithium-sulfur batteries surprisingly

Lithium-sulfur batteries are suitable for both vehicle and grid applications as they are ultra-cheap, high-energy devices. Sulfur is a very low-cost material and the energy capacity is much higher than that of lithium-ion. So, lithium-sulfur is one chemistry that can possibly meet the demand for energy storage at a cheap price. However, the serious problem is, lithium-sulfur batteries suffer from significant capacity fading that makes them almost practically unusable. But, Lawrence Berkeley National Laboratory researchers’ recent surprising discovery could fix this problem.

Carrageenan is extracted from this red seaweeds
Carrageenan is extracted from this red seaweeds

The research team at Berkley Laboratory surprisingly found that carrageenan, a substance extracted from red seaweeds, acts as a good stabilizer in lithium-sulfur batteries. Better stability in a battery means more charge-discharge cycle and an extended lifetime. Gao Liu, the leader of the research team, said,

It (Carrageenan) actually worked just as well as the synthetic polymer—it worked as a glue and it immobilized the polysulfide, making a really stable electrode.

Lithium-sulfur batteries are already been used commercially in limited applications but the “critical killer” in the chemistry is that the sulfur starts to dissolve and creates polysulfide shuttling effect. Polysulfide shuttling is the primary cause of failure in lithium-sulfur (Li-S) battery cycling. To solve the problem, the research team was experimenting with a synthetic binder that holds all the active materials in a battery cell together.

A binder is like a glue and battery makers want this glue to be inert. The synthetic polymer Liu experimented with, worked remarkably well. The reason is, by chemically reacting with the sulfur, the binder formed a covalent bonding structure and was able to stop it from dissolving. This finding motivated the researchers to find a natural material that would do the same thing. Finally, they discovered that carrageenan has similar chemical properties as the synthetic polymer they used in their initial experiments.

Bekley Lab's researcher is working with advanced light source
Berkley Lab’s researcher is working with advanced light source

With this discovery to stabilize lithium-sulfur batteries­ Liu now wants to improve the lifetime of lithium-sulfur batteries even further. The target of the researchers is to get thousands of cycles from lithium-sulfur chemistry. They are striving to find answers to questions like after this polymer binds with sulfur, what happens next? How does it react with sulfur, and is it reversible? Liu said,

Understanding that will allow us to be able to develop better ways to further improve the life of lithium-sulfur batteries.

As lithium-sulfur batteries are much more lightweight, cheaper, and have higher energy density compared to lithium-ion batteries, they are ideal for airplanes and drones. Hence, Berkeley Lab researchers’ surprising discovery may be a game changer in the world of batteries.

Cell Phone Can Make Calls Without a Battery

Vamsi Talla at the University of Washington in Seattle build a mobile phone that can rely only on energy that it could harvest from its surroundings. Imagine if you can send SMS or make a call when you are out of battery. That’s what’s the team trying to achieve.

Ambient light can be turned into a trickle of electricity with solar panels or photodiodes. Radio-frequency TV and Wi-Fi broadcasts can be converted into energy using an antenna. A hybrid system using both technologies might generate a few tens of microwatts.

Cell Phone Can Make Calls Without a Battery – [Link]

6V Lead Acid Battery Charger using BQ24450

6V Lead acid (SLA) battery charger project is based on BQ24450 IC from Texas instruments. This charger project takes all the guesswork out of charging and maintaining your battery, no matter what season it is. Whether you have a Bike, Robot,  RC Car,  Truck, Boat,  RV, Emergency Light, or any other vehicle with a 6v battery, simply hook this charger maintainer up to the battery. The bq24450 contains all the necessary circuitry to optimally control the charging of lead-acid batteries. The IC controls the charging current as well as the charging voltage to safely and efficiently charge the battery, maximizing battery capacity and life. The IC is configured as a simple constant-voltage float charge controller. The built-in precision voltage reference is especially temperature-compensated to track the characteristics of lead-acid cells, and maintains optimum charging voltage over an extended temperature range without using any external components. The low current consumption of the IC allows for accurate temperature monitoring by minimizing self-heating effects.  In addition to the voltage- and current-regulating amplifiers, the IC features comparators that monitor the charging voltage and current. These comparators feed into an internal state machine that sequences the charge cycle.

6V Lead Acid Battery Charger using BQ24450 – [Link]

Solar Power Module v2

Chip McClelland @ hackster.io published his solar li-po battery charger based on MCP73871 to manage the solar and DC charging of the LiPo battery, TPS63020 Buck-Boost Converter and Maxim 74043 LiPo Fuel Gauge. He writes:

I build connected sensor which are often deployed in local parks where there is no access to utility power. Over the past couple years, I have been refining and testing my solar power modules and have arrived at this compact integrated design. I have a number of these deployed and they have been in continuous service for up to two years. I wanted to share this design in case it might be helpful for your projects. I would also greatly appreciate any input or suggestions on this design so v3 will be even better.

Solar Power Module v2 – [Link]

Fuel gauge needs no battery characterization

by Susan Nordyk @ edn.com

The MAX17055 single-cell fuel gauge from Maxim not only eliminates battery characterization, but also keeps SOC (state-of-charge) error to within 1% in most scenarios. With its ModelGauge m5 EZ algorithm, the device provides tolerance against battery diversity for most lithium batteries and applications. It also allows system designer’s to decide when to shut down the device when the battery gets low, maximizing device runtime.

As the battery approaches the critical region near empty, the ModelGauge m5 algorithm invokes a special error correction mechanism that eliminates any error. In addition, it provides three methods for reporting the age of the battery: reduction in capacity, increase in battery resistance, and cycle odometer.

Fuel gauge needs no battery characterization – [Link]

Simple circuit indicates health of lithium-ion batteries

Fritz Weld @ edn.com proposes a simple circuit to check li-ion battery health. He writes:

Lithium-ion batteries are sensitive to bad treatment. Fire, explosions, and other hazardous condition may occur when you charge the cell below the margin that the manufacturer defines. Modern battery chargers can manage the hazardous conditions and deny operation when illegal situations occur. This fact doesn’t mean, however, that all cells are bad. In most cases, you can replace the discharged battery and increase your device’s lifetime. Figure 1 shows the circuit for testing battery packs.

Simple circuit indicates health of lithium-ion batteries – [Link]

Simple circuit indicates a low battery

@ edn.com writes:

The Design Idea in Figure 1 indicates a low-battery condition in an audio test instrument that is powered by four AA cells. As the instrument was otherwise an all-discrete design, this same approach seemed more in keeping with the spirit of the project than the use of a single-sourced integrated circuit.

Simple circuit indicates a low battery – [Link]

Flow battery can run for 10 years with zero maintenance

by Jan Buiting @ elektormagazine.com:

Harvard University researchers have developed a low-cost flow battery that stores energy in organic molecules dissolved in neutral pH water. In their report (see below) they claim that the new battery can run for a decade or more without maintenance.

Flow battery can run for 10 years with zero maintenance – [Link]

2.5V-4.2V input to 3.3V output – 1A Buck Boost Converter using LTC3441

This circuit can produce an output of 3.3V and 1A current continuously for a voltage input varying from 2.5V to 4.2V. The LTC3441 is a high efficient buck boost converter which plays a vital role in portable instrumentation because of its fixed frequency operation. This circuit produces the output from a single Li-ion battery. Multiple cells can also be used within the specified range of input voltage.

Features

  • Input(V): 2.5V DC to 4.2V DC
  • Output(V): 3.3V DC
  • Output load: 1A
  • PCB:21mmX12mm

2.5V-4.2V input to 3.3V output – 1A Buck Boost Converter using LTC3441 – [Link]

Replacing a dead iPhone battery

discuss his experience replacing an iphone battery @ edn.com:

About a week ago, in preparing to run some errands, I plugged my iPhone 4S into the charger in my car so that I could stream Pandora while I drove. Oddly, a “this accessory may not be supported” message appeared on-screen; when I unplugged and re-plugged the iPhone to the charger, it didn’t reappear, so I didn’t think anything more of it … until a half hour later, when the iPhone again alerted me, this time with a “low battery” message.

Replacing a dead iPhone battery – [Link]