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Self-monitored, safe and smart batteries

November 16, 2020



Bratislavsky kraj


Outsmarting thermal runaway through predictive maintenance is within everybody’s benefit

Just like gold, the battery industry has been around for a long time now, and the users are naturally questioning, “can there be a new, or better element fully replacing them?”, and just like for gold, for batteries as well we can answer with a question “is what we have now so bad, or did we never use them properly?”. To get relief from this agonizing question, let’s have a look into the battery industry as such. What are some of the general trends within “the batteries’’? why are people so afraid of some types of batteries? and of course, how can we push this incredible energy-filled instrument to their full potential in the safest way possible!

Based on what market researchers say, the global battery market within the forecast period of 2020–2025 will have a compound annual growth rate of more than 12%. The number is undoubtedly massive if only in 2019 it was valued at USD 108.4 billion . The reasons vary, of course, the increased adoption of electric vehicles, the renewable sector, consumer electronics, and surely, a rather large piece is taken by the rapid growth in lithium-ion batteries consumption.

The secondary batteries: common trends and difficulties

While primary batteries are designed to be used only once, secondary – rechargeable types of batteries are allowing energy used then can be loaded up again. Even though this makes secondary batteries more cost-effective in the long run, it also brings up some complications. Let’s try to look into those complications by further classifying the secondary batteries, based on the chemistries used in them:

1. Lithium-ion(Li-ion) – high energy density, little or no memory effect, and low self-discharge, however, have potential energy loss, fragile, safety issues like thermal runaway were documented

2. Nickel Cadmium(Ni-Cd) – Good physical durability; good charge retention; decent cycle life, however, has a high cost; memory effect

3. Nickel-Metal Hydride(Ni-MH) – Resistance to over-charging and over-discharging, no hazardous chemicals included, however, rapid self-discharge while stored, rapidly cut power

4. Lead-Acid – low-cost, serve for non-portable, heavy-duty demands, relatively large power to weight ratio, very low energy to volume and energy to weight ratio

Each of these has its niche applications, and problematic areas framing their growth potential. The lithium-ion batteries(LIB), however, are arguably the most efficient types of secondary batteries for the majority of applications at the moment, this is the main reason why they are estimated to have a market size of 71 billion US dollars by 2025. Another reason being, of course, the price decreases per unit.

Issues common within the energy storage industry:

Basic Safety

Each of the energy storage solutions mentioned above has their niche strengths, however, if we were to identify the main problem occurring in batteries within the global energy storage industry, we would most commonly stumble upon Thermal Runaway, (and other battery thermal management related issues). Thermal runaways: These can be defined as the final critical effect of constant voltage charging. For example, a LIB is overused; the performance can be raised, but heat generation within the battery cannot, eventually bringing the battery to extreme temperatures that can cause an exothermic decomposition of electrodes and electrolyte materials, separator shrinkage, inducing internal short circuit, which itself can be followed by dangerous circumstances. In other, more digestible ways, these are generally caused by electric, mechanical, or heat abuses, these bring to a heat generation that can be too fast and too quick, be followed with smoke, fire, and/or an explosion. Some reasons for thermal runaways other than the main internal short circuit are external abuse like physical damage or the external, environmental temperature.

Battery Capacity Waste

Batteries are essentially energy storage instruments, so if during an operation they give up the heat, vibration, or any other type of energy that is not within their main application spectrum, then these quantities(vi­bration, heat) is purely wasted energy. This is not only a dangerous but also an economically painful stretch for the user – be it an end-user or a business (i.e power plant), it has quantifiable financial impact on the company's bot­tomline. In cases like crack on the battery case, overheating, cooling systems only partially cooling batteries, wrong welding or welding cracks, or just vibration in the applications that the batteries are used in – the battery system loses vast amounts of energy into the air. Many batteries are also found to be affected with the memory effect. when they stop providing the full capacity after continuous ineffective charging(i.e. a half-way-charge). This wasted energy, instead of being recycled, controlled, and used properly is not only just wasted, but transformed into potential danger too.

Environmental & Economic issues / Battery Waste:

It is expected that China alone will produce around 500,000 metric tons of used Li-ion batteries by 2020 and by 2030, the number generally in the world will reach 2 million metric tons annually. Especially when you consider the volumes of secondary batteries production and waste also due to the counterfeit market, rapid adoption of EVs, etc, it is now obvious that the battery industry has been stagnating in terms of recycling and overall end-user instructions. There are of course various waste management strategies, and practices in place to raise awareness and decrease battery waste globally, p, however, the waste largely comes from the misuse of the batteries(i.e due to energy waste, battery memory effect, etc.), and unfortunately, there aren’t any large-scale feasible practices in place to tackle this issue.

Battery predictive maintenance performed properly solves problems and add values:

The rise of the energy storage industry and the problems within the batteries are not something new either, thus, the market has been trying to fix them for quite some time as well. There are various thermal management solutions for LIBs and lead-acid batteries, welding cracks and caging damages, recycling old batteries, vibration management, preventive maintenance to control thermal issues, etc.

Unfortunately, there is no feasible and entirely effective maintenance solution for batteries by far, and with the rising demand from the market – either the safety or efficiency of batteries is being compromised. The main reasons are the fact that making batteries smarter would mean making them bigger, bulkier, and/or more expensive, thus the market, as always, chooses the most practical solution out there.

We in RVmagnetics, being essentially a data production company, can address all the above-mentioned issues with the safest, smallest, and most relevantly inexpensive solution imaginable! Our solution lays in MicroWire – a sensor of physical quantities like temperature, vibration, position, electric current, magnetic field, etc.

The MicroWire is a miniaturized sensor, thin like human hair, it is resistant to chemically aggressive environments, thus can be embedded directly into the batteries’(even supposing the internal hazardous, acidic environments), and provide contactless and spark-less sensing (this prevents any ignition possibilities). It has an operating temperature range of –273 to 600°C and a sensing frequency of up to 10.000 times per second and a diameter of only 50um. Ultimately we have a sensor and sensing system that provides accurate non-destructive testing and measurements from within the battery, without any contact or wiring, with no influence from an aggressive chemical environment, thus enabling predictive maintenance for the whole battery unit in the safest way possible.

Can you imagine a secondary battery like lithium-ion warning you, when it gets an internal chemical reaction which in two weeks may cause a thermal runaway? We can now make this possible, making the batteries work at their maximum efficiency, without compromising the safety of the application, thus increasing the comfort and decreasing the waste!