Tag Archives: Li-Ion

Could Sodium-ion Batteries be a Replacement for Li-ion Batteries?

Batteries made by Tiamat, a sodium battery startup spun off from the National Center for Scientific Research in France.

In early 1990s lithium-ion batteries started gaining popularity as a substitute for nickel-cadmium batteries. They have higher energy density, low self- discharge, and low maintenance, but it was soon found that they have short life span, unstability which causes security concerns and creates the need for protection circuits (to maintain it within safe limits), and are really expensive to produce. Lithium is scarce (or is soon going to be), only 0,06% of earth crust is made of this material and its mainly found in South America. A start up called Tiamat formed by scientists at several French universities proposed an alternative to lithium-ion batteries, they developed the first sodium-ion battery in industry standard 18650 cell size.

Unlike Lithium, sodium makes up 2.6% of earths crust which makes it the sixth most abundant element. As a raw material sodium sells at about $150 a ton compared to $15,000 a ton for lithium. Sodium batteries are cheaper to produce than lithium batteries, leading to a lower selling price. Also, the lifespan is about ten years compared to lithium which is 4 years and Sodium-ion batteries can last for up to 5000 charge/discharge cycles. Tiamat batteries are not a fire hazard, and provide more stability for a cheaper price.

Scientists want to use these batteries mainly for mass storage of interment renewable energies such as solar o wind. Tiamat is not looking to make Li-ion batteries disappear, instead they want to focus on their long lasting power, and use it for stationary storage. This type of battery could be used in electric cars to allow lasting trips with short recharge time. Production has not started, but when it is approved, and they start to sell France could become a leader in this type of technology. This startup has the support of RS2E (Réseau sur le stockage électrochimique de l’ énergie) a French research network dedicated to energy storage devices, and they plan to launch the product on 2020.

Nowadays, lithium batteries are used mainly for smartphones, laptops, and cars that means that if a new technology was going to replace them, a much better alternative would be needed. Even when sodium batteries are cheaper and safer they still have performance issues that could affect their sales, but as Tiamat said they are not looking to replace these and their market is completely different. For now, the cells produced offer only about half of the energy density of Li-ion and are yet to be improved in many aspects.

[Source]

Flexipower – A portable, Controllable, Dual Channel Power Supply

Hobbyists, makers, students and pretty much everyone who works with electronics has encountered the same issue, not having a handy power supply to test their projects. Usually, controllable power supplies are big, expensive and for some people difficult to access, and most small power supplies are not controllable. As a result, Roberto Lo Giacco created Flexipower, a small, portable, flexible, and remotely controllable dual channel power supply.

Flexipower is controlled via a mobile application and its battery operated. It can work up to a voltage of 20 V and a current of 1 A (per channel). Power supply is powered by two cell Li-Ion or Li-Poly batteries which provide 8.4 v when fully charged, to reach higher voltages the battery is fed into a voltage step up circuit, and to get lower voltages the battery is fed into a high current linear voltage regulator. Also, a simple voltage divider along with the 10-bit ADC is used to measure the produced voltage, and adjust accordingly.

Current measuring is done through a 1 Ohm shunt resistor network made by ten 10 Ohm resistors in parallel which results in 1 mV voltage drop per mA. In the case of currents lower than 320mA, the integrated circuit INA219 is used to obtain a very precise reading. When the supplied current goes above the capacity of the INA219 the shunt resistor voltage drop is measured using the 10 bit ADC.

As mentioned before, Flexipower uses 2 rechargeable batteries that are charged via a barrel jack connecting a 12 V source capable of around 1 A. An RGB LED is used to inform the user about the status of the device (power on, battery warning, connection status etc.). The LED is also used to indicate the battery status. Additionally, each channel has a green/red LED to indicate if it is enabled (green), or over current (yellow).

Furthermore, the device can create “Flexipower SSID”, an access point for people to connect and control the power supply. The app was created to avoid using a big LCD screen with limited data logging capabilities. The app allows control, unlimited data logging and visualization just with the use of a smartphone.

For complete specifications, list of materials used, schematics and app download go to official website. The creator always tried to minimize components costs while still providing a lot of capabilities. It still can be improved, but it’s a project that could make the life of people easier. Its important to clarify that this device is not a replacement for benchtop power supplies, but for portability is a great option.

Rechargeable Magnesium Batteries – Safer And Cheaper Than Li-ion Batteries

Researchers at the University of Houston reported in the journal Nature Communications the discovery of a new design that significantly improves the development of a battery based on magnesium. Magnesium batteries are considered as safe resources of power supply – unlike traditional lithium-ion batteries. They are not flammable or subject to exploding – but their ability to store energy is very limited. But the latest discovery of the new design for the battery cathode drastically increases the storage capacity.

Energy diagrams for the intercalation and diffusion of Mg2+ and MgCl+
Energy diagrams for the intercalation and diffusion of Mg2+ and MgCl+ in magnesium batteries

In order to make magnesium batteries, the magnesium-chloride bond must be broken before inserting magnesium into the host, and this is very hard to do. Hyun Deog Yoo, the first author of the paper, said,

First of all, it is very difficult to break magnesium-chloride bonds. More than that, magnesium ions produced in that way move extremely slowly in the host. That altogether lowers the battery’s efficiency.

The new battery technology stores energy by inserting magnesium monochloride into titanium disulfide, which acts as a host. By keeping the magnesium-chloride bond intact, the cathode showed much faster diffusion than traditional magnesium batteries.

The researchers managed to achieve a storage capacity density of 400 mAh/g – a quadruple increase compared with 100 mAh/g for earlier magnesium batteries. This achievement even overpowered the 200 mAh/g cathode capacity of commercially available lithium-ion batteries. Yoo, who is also the head investigator with the Texas Center for Superconductivity at UH, confirmed this fact.

The cell voltage of a magnesium cell is only 1V which is significantly less than a lithium-ion battery which has 3.7V cell voltage. Higher cell voltage and high cathode capacity made Li-ion batteries the standard. Li-ion batteries suffer from an internal structural breach, known as dendrite growth what makes them catch fire. Being an earth-abundant material, magnesium is less expensive than lithium and is not prone to dendrite growth.

The magnesium monochloride molecules are too large to be inserted into the titanium disulfide using conventional methods. The trick they developed is to expand the titanium disulfide to allow magnesium chloride to be inserted rather than breaking the magnesium-chloride bonds and inserting the magnesium alone. Retaining the magnesium-chloride bond doubled the charge the cathode could store. Yoo said,

We hope this is a general strategy. Inserting various polyatomic ions in higher voltage hosts, we eventually aim to create higher-energy batteries at a lower price, especially for electric vehicles.

Integrated 36V buck battery charger provides seamless backup power

By Graham Prophet @ eedesignnewseurope.com:

LTC4091 is a complete lithium-ion battery backup management system for 3.45V to 4.45V supply rails that must be kept active during a long duration main power failure. The LTC4091 employs a 36V monolithic buck converter with adaptive output control to provide power to a system load and enable high efficiency battery charging from the buck output.

Integrated 36V buck battery charger provides seamless backup power – [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]

TP4056 3V3 Load Share Upgrade

A lot of project are battery powered and some of them need dual battery links. Robert on hackaday.io had shared his new project that shed light on this issue. He built an load sharing addon board with the ability to charge the battery while the project is operating.

Many Chinese charger boards are out there based on TP4056, but these boards don’t have the load sharing or voltage regulator features.

Load sharing means that you can power your circuit in two ways, from battery and from Vcc if a charger is connected. Once the charger is connected the battery will start charging and the load will be powered directly from Vcc. Robert added this feature to a recent design and also he added voltage regulation by using MCP1252.

The Components needed to build this project:

  • 1x  MCP1252-33X50/MS Power: Management IC / Switching Regulators
  • 1x  FDN304P: Discrete Semiconductors / Diode-Transistor Modules
  • 1x  SGL1-40-DIO: Schottky diode
  • 2x  100k 1206 resistor
  • 3x  10uF 1206 capacitor X7R
  • 1x  2.2uF 0805 capacitor X7R
  • 1x  ON/OFF switch (optional)
  • 2x  2 pin pcb connector
  • 1x  PCB from OSHpark

This schematic was inspired by multiple designs and modified by Robert.

“The advantage of MCP1252 is automatic buck/boost feature, it will maintain the regulated output voltage whether the input voltage is above or below the output voltage (2.1 to 5.0 V input range) so it is ideal for the lithium battery voltage. If you read the datasheet for the MCP1252-33X50I/MS there is clearly specified what type of MLCC capacitor should be used.”

The maximum output current of this board is 120mA and the output voltage is 3.3 V. It may sound not that suitable for your projects if you want to power an ESP8266, but still you can build your own board with different components to achieve the outputs you need. For example, by using MCP1253, which is identical to MCP1252, you will get  higher switching frequency (1MHz). Robert’s plan is to use this board with CO2 sensor (about 30 mA) and other low power sensors, some MCU and LCD, which can be powered using 120 mA.

Some measurements will be done to test the functionality of this board. To keep updated with the news of this project, you can follow the project on hackaday.io. You can also check other projects by Robert here.

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]

Supercapacitors Surpassing Conventional Batteries

Researchers at the University of Central Florida have been looking for alternatives for lithium rechargeable batteries which are largely used in every device.

Using two-dimensional (2D) transition-metal dichalcogenides (TMDs) capacitive materials, they are building a new supercapacitor that overcomes the performance of conventional lithium battery and replaces its efficiently.

Transition metal dichalcogenide monolayers (TMDs) are atomically thin semiconductors of the type MX₂, with M a transition metal atom and X a chalcogen atom. One layer of M atoms is sandwiched between two layers of X atoms.

TMDs are considered as promising capacitive materials for supercapacitor devices since they provide a suitable current conduction path and a robust large surface to increase the structure’s high energy and power density.

Researchers have developed “high-performance core/shell nanowire supercapacitors based on an array of one-dimensional (1D) nanowires seamlessly integrated with conformal 2D TMD layers. The 1D and 2D supercapacitor components possess “one-body” geometry with atomically sharp and structurally robust core/shell interfaces, as they were spontaneously converted from identical metal current collectors via sequential oxidation/sulfurization” according to the research paper.

The new prototype is said to be charged 30,000 times without any draining, 20 times the lifetime of an ordinary battery.

“You could charge your mobile phone in a few seconds and you wouldn’t need to charge it again for over a week,” says UCF postdoctoral associate Nitin Choudhary.

This research was published in the NANO science journal, you can check the scientific paper here.

Nanotechnoloy – Nano coating prevents exploding Li-ion batteries

Lithium-ion batteries are very popular as they’re lightweight and have high energy density. But at the same time, li-ion batteries are very sensitive to overcharge/over discharge. An internal short circuit can cause fire and it may even lead to a violent explosion. Fortunately, nanotechnology found a way to prevent this kind of nightmare. How? let’s discuss:

Why Does li-ion Battery Explode?

When a device draws too much power from a Li-Ion battery, it heats up and thus melts the internal separator between the two flammable electrolytes. This phenomenon ignites a chemical reaction between the electrolytes causing them to explode. Once their package ruptures, the oxygen in the surrounding air helps the flammable electrolytes to catch fire. The fire then spreads quickly to other cells and loads a thermal runaway.

Thermal runaway in Li-ion Battery
Thermal runaway in Li-ion Battery

During a thermal runaway, the high heat of the damaged or malfunctioning cell can propagate to the next cell, causing it to become completely thermally unstable as well. In some worse cases, a chain reaction occurs in which each cell disintegrates at its own timetable.

So, in a nutshell, Li-ion cells possess the potential of a thermal runaway. The temperature quickly rises to the melting point of the metallic lithium and cause a violent reaction, which finally causes an explosion.

How Can Nanotechnology Prevent This?

Recently conducted research shows that atomic layer deposition (ALD) of titania (TiO2) and alumina (Al2O3) on Ni-rich FCG NMC and NCA active material particles could substantially improve Li-ion battery’s performance and allow for increased upper cutoff voltage (UCV) during charging, which delivers significantly increased specific energy utilization.

Atomic Layer Deposition in li-ion CellsAtomic Layer Deposition in li-ion Cells
Atomic Layer Deposition in li-ion Cells

 

A company called Forge Nano claims to prevent this thermal runaway situation by never letting it get started even if the battery electrodes are shorted out. Forge Nano’s precision coatings on cathode and anode powders protect against the most common degradation mechanisms found in Li-ion batteries.

The benefits of Forge Nano precision coatings include extended battery life and greater safety, especially in extreme situations such as high-temperature operation, fast cycling rates, and overvoltage conditions.

By implementing lithium-based ALD films in nanostructured 3D lithium-ion batteries, significant gains in power density, cycling performances during charge/discharge, and safety is noticed.

What’s the Result?

Some of Forge Nano’s accomplishments in the Li-ion battery space includes:

  • Increased lifetime of commercial cathode material by as much as 250%
  • 15% higher energy density in large format pouch cells (40 Ah) that pass nail penetration testing
  • 60% reduced gas generation in cathode material
  • A low-cost high-voltage cathode powder with exceptional performance
  • Increased rate capability of conventional materials for enhanced fast charge acceptance using Forge Nano’s proprietary solid electrolyte coatings

    ForgeNano Claims Their Technology as Best Solution
    ForgeNano Claims Their Technology as Best Solution

Since the solution found by the research, Forge Nano has been working on a commercial version of the product that they finally believe they can place in the market very soon.