When it comes to designing the latest electronic device or gadget, all too often, the battery is the last thing to be considered, leading to performance issues, safety concerns, and in some cases, costly redesigns because the selection of battery was left only after the product was designed.
Michael Rogers, MD of Uniross, the industrial battery manufacturer, discusses points to keep in mind when designing an electronic device or gadget that relies on a battery for its source of power. He covers 10 points to consider before embarking on a design.
Consult a specialist:
Whilst the internet is a good source of information, it can also be inaccurate and unreliable. Rather consult with a battery engineer or specialist before you start any new development.
Use commonly available batteries:
Always try to design your equipment around commonly available battery sizes and chemistries. Due to economies of scale, mass produced batteries are always cheaper and more readily available, and remember to ascertain their dimensions before embarking on the design of the product.
Although batteries are generally manufactured according to standard sizes, it is quite common to find marginal dimensional differences between manufacturers and even batches. Where possible, try to design your equipment to accommodate these dimensional tolerances. This will also allow you to change manufacturers later down the line, should the need arise.
All batteries, no matter the chemistry or manufacturer, are susceptible to extreme temperatures – be that high or low temperatures. It is therefore imperative that you consider the environmental operating temperatures in which you will be placing the battery. These temperatures can have an adverse effect on the performance on the battery.
Allow batteries to breathe:
Where possible, try to design the battery compartment to allow the battery to breathe (vent) and expand or contract. Batteries can expand and contract during operation, and in worst-case scenarios, even vent dangerous gases. A battery compartment, which allows for this phenomenon, is good design practice.
Avoid additional heat:
Batteries are very susceptible to high temperatures, so where possible, try to locate batteries as far away as possible from any heat source to prevent service degradation. A provision for ventilation or insulation can help.
The use of good quality battery contacts is essential to good battery performance. Pure nickel is one of the best materials that one can use in the manufacturing of a battery contact.
Low voltage shut off:
Design the equipment to switch off after the battery voltage has dropped below the functional limit of the device. This is especially true of devices, which leave the battery on a virtual short circuit when the voltage level has dropped. Electrolyte leakage can occur under these conditions.
Not all batteries will give the same service life. In addition, there are many factors which can affect the service life of a battery. Factors such as environmental conditions (high and low temperatures) and operational conditions (rate of discharge and depth of discharge that all contribute to the service or cycle life of the battery.
If you are expecting to get 1,000 cycles from a rechargeable battery, for example, you need to consider the conditions the battery is being subject to. If uncertain, rather have a battery specialist perform a life cycle simulation test. In that way you can be certain that your battery will indeed give you the service life you’re expecting.
Most batteries are considered to be hazardous by the major airlines and their regulating bodies, thus classifying them as restricted cargo. This does not mean that you cannot transport batteries by air, but it is increasingly more difficult to do so. This is especially true if the equipment you designed contains a lithium type battery. Before starting the design process, simply consult with a battery specialist who can inform you of the transport regulations and restrictions for the various battery chemistries to avoid costly expenses after the fact.
By Michael Rogers, managing director of Uniross Batteries