Customers who require battery packs for devices have a wide selection to choose from to provide the appropriate amount of power to applications. When selecting a battery pack, choosing a customized design provides you with more control and design freedom when it comes to picking specific materials, charge rates, battery enclosure designs, and capacities.
One factor to consider is a battery's lifespan when seeking a custom battery pack design.
How Customizing Battery Electronics Helps to Improve Lifespans
Battery pack electronics consist of the actual cells, wiring harness, components such as relays and resistors, the battery management system (BMS), the charger, and sometimes a heating/cooling system depending on the application and the environment. Each factor can be customizable, or a mixture of customization and ready-made components. Customizing these components allows you to make the battery specific to an application, which can help improve battery lifespan.
Custom battery packs utilizing a battery management system (BMS).
For example, a battery pack used for an outdoor power tool, and one used for an indoor UPS system have different load requirements, power capacities, and mechanical stresses. You would need to design a cable assembly and battery enclosure to withstand the constant vibrations and shocks that may be experienced when operating the power tool or when it is dropped to the ground. The design specifications would consider this factor and the risks that would be involved. If the harness becomes loose and disconnects, the device fails.
For lithium-based batteries, the BMS is designed to monitor the state of health (SoH) and state of charge (SoC) of the battery pack. This electronic device also monitors the temperature and voltage, as well as providing overcurrent protection. The BMS can detect if the battery pack is charging too quickly and reaching the high voltage limit. In this instance, the BMS can limit or stop the current to prevent battery damage and a loss of capacity.
This protection device can also prevent over-discharging of the battery pack. If the demands of the application force the battery pack to reach a very low voltage, the BMS can disconnect the power to protect the battery and improve its lifespan.
Improving Battery Lifespan with Customized Mechanical Features
The mechanical design of the battery pack brings together all the cell elements to create a battery that has a long-lasting capacity and provides the ultimate power. While selecting the right cell chemistry is essential to determine the battery's shelf-life, you also must consider the container in which will hold the electrolyte, the anode, and the cathode. Battery cell manufacturing offers a range of different cell formats, such as prismatic, cylindrical, pouch, and button configurations.
Each cell formats the active ingredients inside. They can also provide additional benefits such as venting, varying location of the positive and negative tabs, and safety features to address thermal runaway. Customizing the mechanical features can allow you to select a cell format that best fits into the available space of the application.
If you have an application that is very thin, you may require a pouch cell format that can easily provide battery power despite space limitations. However, due to the lack of structural strength of the pouch since they lack rigid materials, you may deal with an increased risk of battery damage. Customizations in battery pack designs can take dynamic stiffness, static stiffness, and the movement of internal components into consideration to provide a design that can offer greater protection for the battery pack. If a pouch battery must be used, the customer can consider how the enclosure can be changed to provide more strength, stability, and venting options.
Customizing Charge and Discharge Rate Parameters
Battery packs go through a certain amount of charging and discharging cycles. Each type of battery chemistry has a range of charge/discharge that the cell can go through before it starts to lose capacity and experiences aging. For example, a lithium-ion battery has an average lifespan of 300 cycles up to 500 cycles depending on usage -- or roughly 2-3 years.
Battery cell rate parameters are measured in amp-hours (how much amps can be given in a set amount of time) and as a C-rating (the amount of time to charge or discharge the battery). Both parameters can be customized to improve the lifespan of the battery.
To change amp hours, a manufacturer can place the batteries either in a series or a parallel connection format. If the batteries are placed in a series, the voltage amount increases without increasing the capacity. This format leads to having more voltage from the battery for high power-demand devices. When you place batteries in a parallel connection, the amp increases yet the voltage remains the same, as this format leads to a longer battery lifespan.
In the case of C ratings, the lower the rating that the battery has increases the lifespan of the battery. So, if a battery has a 0.05 C rating (C/20), this measurement means that it has a 20-hour charge/discharge. While this C rating may be good for some devices, other applications will require faster charging and discharging rates.
Selecting the best C rating will depend on the application’s power needs. While selecting a high C rating will be ideal for some high-powered devices, the offset is that it will lower the overall lifespan of the battery due to an increase in the number of charging cycles it will experience.
Summary
The application itself will dictate the types of customizations that will be required to meet specifications. Manufacturers can provide the custom design required to power your device, while also providing suggestions regarding how certain changes can be made to improve the overall lifespan. Then the customer can select the appropriate changes that will not impact the battery pack's productivity.
