Topic 1: Introduction to Battery Safety Basics
Batteries Have Evolved
There has been a fairly well published science portraying the electrical-chemical processes involved in battery energy storage and then usage. Fortunately, there has never stopped being improvements on this process since it was originally configured by Volta and others. Unfortunately, while the newer materials and processes have evolved, there has not been a complete understanding of the complexities of the newly evolving technology.
From the manufacturer-retail side, these newer applications mean a volume of higher sales potentials. Again, on the less fortunate side, the availability of (a) newer scientific developments, (b) increased applications, and (c) utilization in popular, high profile consumer markets, has lead to increased battery damage incidents.
To the extent that the science allows, most manufacturers have attempted to control the hazards associated with such incidents through research, design, good quality control procedures, and hazard analyses. But many of the hazards still remain and addressing them necessitates well formulated instructions and warnings. The writing and analyses of these warnings and instructions, as well as what role such warnings might play in accidents is where we at Miller Engineering can make a contribution. Writing effective warnings and instructions starts with knowledge about the product – such knowledge which might reveal the hazards and remedies which warnings are intended to address. The following is some of that knowledge we have gained from other expert sources in the field.
Why so many battery types?
Optimizing a battery for an application usually deals with such issues as:
(a) if a low delivery of electrical energy is required; if a high amount of delivery energy is required;
(b) for what duration will each demand use be;
(c) how long would one like the battery energy to be available over hours – minutes, days or longer;
(d) what weight of battery can an application tolerate; and, of course,
(e) what risk might be associated with the sale and use of any “optimized battery solution”.
Much of this optimization is embodied within the electrochemical expertise area, which, of course, resides heavily with researchers and manufacturers.
The simple electro chemical-physics behind the battery is that certain elements have additional electrons in their molecular structure they can give up electrons, as designated by the (+) in their chemical designation. Other elements have room for additional electrons in their molecular structure and they are designated with a (-).
It is not surprising that the specifics of a particular battery’s design is proprietary. As such, one typically only discusses the general model which describes the types of components within a design. The first source to thank is OSHA for their requirements for Safety Data Sheets (previously MSDS). With these, one does have some idea what internal chemicals and components exist within a given battery, assuming accurate disclosure. A second source of really useful information about batteries come from companies other than battery manufacturers which have had to gain expertise in order to make and market products which support the batteries, like those supplying battery analyzing, testing and charging devices. There are several of these which provide useful battery information as a public service, in the interest of education and safety. I found the Cadex company websites particularly useful in this regard. They call their site education site “batteryuniversity.com”. I have used it liberally including some of the contents herein, and I can recommend it to readers of this article.
For example, the diagram below is the simplest way of explaining what is happening electrochemically within any rechargeable battery. The only thing that is not named is the elecrolyte which is where the ions are shown moving to and from as they try to achieve electro neutrality during the charging and discharging processes.
When one puts the above illustration in terms of the typical round and long battery, it looks like the following figure. The many components in this figure should suggest that the manufacturing process is not simple.