Designing an IoT application involves a lot of choices. Designers are looking for performance and quality, but need to balance those alongside a low Total Cost of Ownership (TCO).
When it comes to battery choice, it is no different. Decisions about the type of cell needed will likely have been made and datasheets explored – and more often than not the declared performance of the battery options presented are broadly similar. It is natural then, to go for the cheapest option that will ‘get the job done’.
However, not all batteries are the same. Datasheet performance is not always an indicator of how batteries will perform in a year’s time, or in extreme conditions. If batteries have to be replaced in all devices sooner than expected, any short-term cost savings are quickly lost.
While price does not always indicate quality, there are times when it can be a useful guide.
So, what is behind the price of a battery? What are the elements that make a difference in a battery, and how do these elements impact the success of a project, the customer’s return on investment (ROI), and the satisfaction of the end user?
Quality and performance
Batteries are made up of several components that react chemically to provide energy. Although the main chemistry used in a cell might bear the same name from one manufacturer to the next (Lithium-Thionyl chloride, for example), each manufacturer develops its own proprietary recipe.
Various ingredients will be added to the chemistry to offer a more stable voltage, deliver more energy density, limit voltage delays, etc., which explains why performances vary from one cell to another.
The construction of the cell may also differ from one manufacturer to the next; various materials can be used for the anode and cathode, the separators, or the sealing. Their composition and physical properties also vary depending on the quality or the metal grade that is being used.
The sealing is a good example: the glass-to-metal seal that is often used is quite a complex component for which the manufacturing process is key to provide a qualitative sealing performance of the cell. A leaking cell could provoke irreversible damages to an IoT device. To protect it, it is therefore crucial to ensure that the mechanical components used in the battery are carefully selected and controlled.
Same for the casing; if you want the connected object to be resistant in harsh environments, designers may want to make sure that the can of the cell is made of high-grade stainless steel.
Impurities or low-quality active materials and mechanical components can lead to lower performances or safety risks, impacting the reliability of the battery and the repeatability of performance. When the solution is being deployed in the field, safety, performance and repeatability of the performances are equally important.
The manufacturing process should also be taken into account. Does the manufacturer control the products at all stages of the manufacturing process? Are the connections soldered manually or automatically? Automated lines combined with process control at all stages of manufacturing are a guarantee of the repeatability of the results and performance. It also ensures less scrap and easier integration of the batteries in your connected object.
Security and responsibility
Batteries are hazardous goods and as such, they are to be handled with care. The price of a battery can reflect the additional safety features included and the number of relevant certifications.
Battery manufacturers can include additional safety features on their cells to add to their security. Saft, for example, have Li-SOCL2 spiral cells that feature a fuse that can be triggered in case of an external short circuit. These specific cells also feature safety vents that can release the pressure instead of exploding if the cell is subjected to an incident in the field.
Whatever the features chosen, batteries need to pass a number of safety tests and certifications, which are not easy to get. They are tested and re-tested to get the right certifications. This is especially important if your device is deployed in explosive (ATEX) or other risky environments, or if you need to ship your devices.
The manufacturer should also provide technical reports committing them to the lifespan of their products. A few examples of such certifications are:
• The IEC 60086-4 that specifies tests and requirements for primary lithium batteries to ensure their safe operation under their intended use and anticipated misuse.
• The UL1642 that aims to reduce the risk of fire or explosion when lithium batteries are used in products.
• The UN38.3 transport regulation, which also requires several tests to guarantee high safety standards of the cells so they conform to IATA regulations and can be shipped.
The list of the raw materials needs to be certified too and the EU, in particular, has a very strict policy on this matter. All applicable batteries in the EU market must pass RoHS compliance that specifies maximum levels of phthalates for some restricted substances. The REACH certification (Registration, Evaluation, Authorisation, and Restriction of Chemicals) addresses the production and use of chemical substances, and their potential impacts on both human health and the environment.
A battery’s end of life is not the end of the story. As an end user of the battery and in some specific supply chain schemes, you might be held responsible for the disposal and the recycling of the batteries – this is not a cheap exercise.
The EU battery directive (2006/66/EC) specifies an obligation from manufacturers, distributors, or even users, to organise the collection and recovery of wasted industrial batteries to ensure proper recycling.
In these above instances, the price is not only a guarantee of safety, but a token of the manufacturer’s responsibility.
Service
The final piece of the ‘price’ jigsaw is in the additional services.
Batteries can be complex to understand with various factors to consider. You might benefit from the help of a technical expert to help you choose the right solution for your device; this will ensure the success of your project. Ideally, this expert can provide you with a lifetime calculation of your battery whilst taking all the parameters into account.
Once a battery has been selected, there are other decisions that may require professional insight. One might have to navigate the challenges of transporting lithium batteries, get additional certifications for the device, or, once the device is deployed in the field, new issues that were not foreseen may crop up. In these cases, having an expert to turn to, to evaluate the situation, and determine a plan of action can be of great help.
This service is often included as an added benefit with higher price batteries. Having the right support at hand can save you time and money.
Conclusion
There is a lot that goes into the price of a battery.
While the cheaper option might seem sensible to maintain a lower TCO, that is not always the case because of the hidden costs. A poor-quality battery that requires replacement will send costs soaring. Not having the right support or certification can expose both you and your end user to additional costs that eat into the ROI.
That is why Saft use first class components, ethically sourced, to ensure the stability and the reliability of its cells, which are controlled at all steps of the production.
Our selected suppliers are using only high-grade raw material in the cells, ensuring a high resistance in harsh environments. The batteries are amongst the best performers on the market, and we are not afraid of committing over their lifespan.
The production lines we use allow us to integrate the elements in an automatic, repeatable way, without scrap on the customer or integrator side.
Our batteries have received all the necessary certifications, which makes them a favourite choice for many IoT developers conceiving products for the industry.
We support our customers to help them comply with the European Directive regulations and we take care of our batteries’ disposal and recycling.
Finally, we offer an array of support and services throughout our products’ lifetime, including lifetime calculation based on proprietary mathematical models, and aftersales management.
| Tel: | +27 11 466 1156 |
| Email: | [email protected] |
| www: | www.uniross.co.za |
| Articles: | More information and articles about Uniross Batteries |
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