Can battery-powered equipment withstand the elements?
Traditionally, mining has relied upon diesel-powered machinery as the most resilient option regardless of the heat, noise and unavoidable pollutant emissions, all of which necessitate extensive ventilation systems to ensure worker health and safety. Now however, technological developments of Li-ion batteries mitigate against extreme heat and frigid cold, preventing disruption to the battery and greatly increasing their potential applications. This means that more industries, including mining, can embrace electrification, as modern battery-powered equipment can now withstand the inevitable harsh climates of underground mines.
There are, however, several elements to consider when it comes to ensuring a battery is durable and rugged enough to be used in underground conditions:
Coping with the heat
Underground mines are extremely hot and humid places to work and, to some, the idea of batteries being able to withstand this is unfathomable, while combustion engines have proven sufficiently robust for years. However, discounting battery power is a mistake.
Batteries have increasingly been developed to withstand harsh environmental elements, greatly improving their durability and ruggedness in these conditions. Whilst it is true that underground elements such as excessive heat, as well as strong vibrations and exposure to moisture can be disruptive to battery power, these do not prevent batteries from being able to deliver optimal power performance.
Testing capabilities for batteries have been enhanced, allowing manufacturers to expose their batteries to severe elements and ensure they can deliver an effective and efficient performance no matter the climate. At Briggs & Stratton, batteries are designed to operate in extreme temperatures from as low as -20°C to as high as 70°C, to ensure they can deliver powerful, consistent performance when it is needed most.
Staying cool
Machines used for underground mining must be able to transport heavy loads for many hours on uneven terrains whilst combatting heat, moisture, dust, and vibrations. For a battery to deliver a seamless and consistent performance despite these conditions, the temperature of the battery itself must be managed.
The battery management system (BMS) is the brains of the battery and whilst keeping tabs on the temperature of the battery may sound simple, the BMS is more than just a thermometer. To ensure the battery stays within its operating range, the BMS is constantly monitoring and measuring not only the temperature but also the charge and discharge currents, and the voltages of each individual cell bank.
The BMS also adds safety and durability features to the lithium-ion battery by protecting against over voltage and low voltage, short circuit protection and cold temperatures to ensure battery life isn’t lost due to hard conditions.
Since the primary safety concern with improperly managed lithium-ion batteries is a thermal runaway event, the BMS is a critical component. When a lithium-ion battery exceeds its maximum allowable temperature range, it can go into a thermal runaway event whereby the temperature rises rapidly, releasing the battery’s energy. However, this will not occur when the battery is properly managed and protected with a BMS.
Battery design
A poorly designed battery with incorrect housing in an unsafe or uncontrolled environment will greatly impact the health of the battery and its power capabilities. Without a sturdy protective casing that is built and tested to withstand extreme temperatures, impact, vibration, moisture and dirt, the battery could suffer internal degradation and damage to the cells during operation. Avoiding battery degradation through damage in this way is crucial to protecting the long-term health of the battery and therefore the design of the battery itself should always be considered.
The Vanguard battery packs come with an aluminium base that absorbs the pressure from external factors to prevent damage to the internal battery cells. The battery cells are then secured within the battery casing with heavy-duty busbars, connections and contactors that help to keep the matrix secure so that the batteries are not dislodged during use. Careful spacing helps to ensure critical venting for the battery cells to keep them cool during use. Additionally, ensuring that the battery casing is sealed in an effective manner protects the electrical componentry from impact, dust, and moisture, which is why the Vanguard battery range has IP66 protection, protecting from dust and wet weather.
A bonus…improving health and safety
Additional heat production and noise are commonly associated with combustion engines which add to an already tough working environment in underground mines. Battery-powered machinery underground reduces additional heat production, resulting in a quieter and more comfortable environment for mine workers, enhancing health and safety benefits.
Research and development efforts over the past few years have resulted in the creation of high-spec Li-ion batteries that are suitable for use in extreme conditions, such as those associated with underground work. With proper system management Li-ion batteries can combat the demanding needs of the mining industry, such as heat, moisture, and vibration whilst providing the high power that is essential for powering underground machinery and therefore, we are likely to see this electrification trend forge ahead in this sector.
