LEAD ACID vs. LITHIUM-ION BATTERIES

The world is evolving, and batteries are transforming how power is used. It’s time to harness a sustainable, in-demand power source. However, selecting the right battery pack for an application can be challenging, with various factors to consider, such as voltage, safety, cycle life, and capacity. Understanding the key differences between lead-acid and lithium-ion batteries is essential for making the best choice.

Lead acid batteries are also known for being particularly heavy. While weight is often seen as a disadvantage, there are cases where it can be beneficial. In forklifts, for example, the battery acts as a counterweight at the back, offsetting the load in the front and preventing the vehicle from tipping over.

In essence, a lead acid battery provides a straightforward and reliable power source but comes with certain limitations. Its high internal resistance causes it to heat up during charging and discharging, leading to energy loss. This is especially noticeable when large amounts of current flow in or out of the battery, where efficiency can drop to as low as 50%.

Additionally, lithium-ion batteries are significantly lighter. For the same amount of stored energy, they weigh about five times less than lead acid batteries, offering a key advantage for manufacturers when designing equipment.

In essence, lithium-ion batteries provide high energy density, long cycle life, and efficient power management. They retain charge well, integrate with modern technology, and are lightweight. However, they require advanced electronics, have higher upfront costs, and can be sensitive to extreme conditions.

Which Battery is Right for you?

While there are distinct differences between lead acid and lithium-ion batteries, your application will often determine which battery is the right power solution for your needs. A lead acid battery may fit the bill for some short-term applications where high surge currents are all you need, and weight isn’t a factor. 

For everything else, look to lithium-ion solutions, such as the Vanguard Battery, for an intelligent battery that can provide superior performance over the lifetime of your equipment.

Drink Up

Lead acid batteries get thirsty. The plates in a lead acid battery need to be continuously soaked in a liquid mixture of sulphuric acid and water to operate correctly. Over time, the water portion of that mixture in flooded lead acid batteries, such as those used in golf carts or some forklifts, will need to be replenished.

A flooded lead acid battery requires regular watering to replace the water that evaporates out of it through normal use. (Note: Sealed lead acid batteries do not require watering). This ‘watering’ should occur on an as-needed basis and should be conducted after you charge the lead acid battery to ensure it’s healthy and safe for use. Over-watering can significantly damage the battery by diluting the electrolyte solution or causing the battery to overflow, while not watering at all can lead to performance issues.

Block and Tackle

The majority of commercial batteries, whether lead acid or lithium-ion, are constructed in large, integrated blocks. These blocks consist of numerous cells that are permanently interconnected, meaning that if a single cell or component fails, the operator is generally required to replace the entire assembly.

By breaking those blocks down into smaller, modular components, both serviceability, flexibility, and safety of the battery can be increased. This is why Briggs & Stratton developed the Vanguard lithium-ion batteries around a modular concept.

A module comprises just 32 small cylindrical cells, and in the case of a failure within a larger pack, the user is typically required to replace the entire assembly, resulting in significant cost implications. However, with the Vanguard lithium-ion battery, only approximately eight percent of the pack's cells require replacement if a failure occurs, owing to the innovative design and modular construction of the cell modules within the pack.

The BMS also adds safety and durability features to the lithium-ion battery. It offers overvoltage and undervoltage protection, short circuit protection, and cold temperature protection to ensure the battery’s lifespan is not compromised by harsh conditions.

Additionally, the BMS provides high-temperature shutdown capabilities and smart charging. Since the primary safety concern with improperly managed lithium-ion batteries is thermal runaway, the BMS is a critical component. When a lithium-ion battery exceeds its maximum allowable temperature range, it can enter a thermal runaway event—the temperature rises rapidly, releasing the battery’s energy and potentially causing a fire. This only occurs when the battery is not properly managed or protected with a BMS. To mitigate thermal runaway risks, the Briggs & Stratton incorporated additional safety layers into the Vanguard lithium-ion battery packs. They are designed with safety measures that disconnect when certain data points become too high or low, unlike lead-acid batteries, which lack such safeguards.

In the event of a short circuit in a lead-acid battery, there is no protection for either the battery or the user. However, with the Vanguard lithium-ion batteries, the system can effectively "turn off the switch," open the circuit, and prevent rapid energy discharge, safely avoiding a thermal runaway event.

Safety is First with lithium-ion batteries

Taking all safety concerns into consideration, Briggs & Stratton added extra layers of safety to the battery packs. The industry has learned from earlier safety issues with lithium-ion batteries caused by design errors. By incorporating the battery management system and the additional layer of inherent safety it provides, the battery gains substantial benefits in terms of functionality and safety.

In conclusion, lithium-ion, with proper system management, is safer, longer-lasting, and more powerful than lead-acid.

Lithium-Ion Lifecycle 

Compared to lead-acid batteries, lithium-ion batteries are more environmentally friendly throughout their lifecycle. They are cleaner to produce, cleaner to consume, and have a longer lifespan in the field. As a result, less waste is generated over the battery's life, and when it’s time for a replacement, the battery can be recycled or repurposed in another application. Vanguard batteries are specifically designed for easy repurposing and recycling, with reusable aluminium castings and easily removable cell modules.

Many are familiar with the established infrastructure for recycling lead-acid batteries, initially developed to handle the nickel-cadmium batteries once used in power tools. This infrastructure is often used for recycling car or golf cart batteries. A similar system is now being developed for the end-of-life management of lithium-ion batteries, with several companies working to integrate these processes.

Additionally, there are companies specialising in recycling and refurbishing lithium-ion batteries. In Europe, Vanguard collaborates with NOWOS to extend battery life through repair and remanufacturing, promoting a circular economy. This approach helps ensure batteries maintain performance while minimising their environmental impact at the end of their life.

Vanguard steps it up

While all batteries contain materials that could be harmful to the environment if improperly disposed of, lead acid batteries present the added risk of potential sulphuric acid and/or lead leakage if damaged or stored incorrectly. Both substances can contaminate soil and groundwater and are linked to negative health effects in humans.

Lithium-ion batteries are not subject to the same 'leakage' concerns as lead acid. Nevertheless, Briggs & Stratton has engineered the Vanguard lithium-ion batteries to be particularly environmentally stable and durable. These batteries feature an outstanding Ingress Protection (IP) 67 dust and waterproof rating, which sets them apart from many other batteries on the market. The IP rating indicates the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact, and water.

The IP67 rating means that the Vanguard lithium-ion batteries can be submerged in up to a metre of water for 30 minutes without water infiltrating the battery. Essentially, the Vanguard lithium-ion batteries can be submerged in water, pressure-washed, or left outside in the elements without the risk of moisture or water ingress damaging the pack. In contrast, batteries with lower ratings could become unusable under such conditions.

While it is never advisable to intentionally expose any battery to such situations, the IP67 rating ensures that, in the event of an accident, the Vanguard batteries remain protected. This reduces the risk of a potentially wasted battery and mitigates any environmental impact caused by damage.

A Greener Alternative

Batteries are a reliable alternative power source, and there are unique instances where a battery is the best choice for the job. There are certainly applications where it is safer for operators and the environment to use a battery, particularly in indoor locations, such as building construction after the walls and ceiling have been put in place.

The absence of emissions allows operators to continue working safely without concerns about air quality. Reduced noise emissions are not only beneficial for the user, but also enable operators to work in sensitive areas and timeframes. Additionally, the lack of vibration enhances the operator experience, leading to improved productivity.

There are also applications where explosions due to environmental factors pose a significant risk. For example, in natural gas drilling or oil fields, there is concern about natural gas leaking into the atmosphere and being drawn into running engines. Battery-powered solutions are particularly advantageous in these situations, as they eliminate these risks. The ability to power equipment without combustion can greatly enhance productivity on job sites where open flames and sparking are major concerns.

The benefits and drawbacks of lithium-ion and lead-acid batteries are now widely recognised. Ultimately, the choice of battery solution for equipment depends on the priorities of the OEM or user. For applications requiring lithium-ion batteries, the Vanguard lithium-ion battery packs and the additional Battery System components present an optimal solution.

Engineered as a flexible, integrated electrification system, capable of delivering between 1,5 kWh and 70 kWh of power, these batteries are a crucial option in a market that increasingly seeks emissions-free and sustainable alternativesto comply with regulatory and cost constraints. Their ability to offer versatile power and performance makes the Vanguard lithium-ion battery packs well-suited to satisfy the varied demands of numerous industries.

_{* Total energy measured using a 0.2C discharge per IEC 61960-3:2017}