As the material handling and ground support equipment sectors embrace lithium-ion batteries and outdoor charging infrastructure, they need battery connectors designed with innovative sealing and thermal management solutions in mind. This is the first part of a two-part article exploring the shift to Li-ion technology and its implications for connector design. The next part will focus on sealing requirements, thermal considerations, and key features engineers should prioritize when selecting connectors for outdoor and fast-charging environments.
Lithium-ion (Li-ion) batteries will power the future of off-highway equipment. An increasing number of material handling and airport operators are transitioning from internal combustion engine (ICE) and lead-acid battery systems to more efficient Li-ion solutions. Driven by improved operational efficiencies, sustainability initiatives, and enhancements in lithium-ion technology, this ‘electrification of everything’ trend is expected to continue.
However, with new power sources come new technical demands. Li-ion-powered equipment requires innovative battery connectors that can handle higher thermal loads and support increased battery monitoring. The growth of outdoor charging also necessitates sealed connectors capable of withstanding exposure to moisture, dust, and debris.
Today, new battery connectors are entering the market that offers engineers enhanced performance and added functionality to support their next-gen electric equipment.
A comparison: ICE, lead acid, or Li-ion?
To understand the latest battery connector designs, it’s helpful to compare the main power options available today and understand why lithium-ion is experiencing such rapid growth. Engineers evaluating power solutions for off-highway equipment, such as forklifts, belt loaders, and excavators, typically choose from three main options:
- Internal combustion engine (ICE): ICE systems use an internal engine to power their operation. These engines often rely on fossil fuels, such as gasoline or diesel, but can also use renewable or alternative fuels, including natural gas or ethanol.
- Lead-acid batteries: Invented in 1859, lead-acid powered equipment relies on an electrochemical reaction between lead plates immersed in sulfuric acid to produce electricity.
- Lithium-ion batteries: First produced commercially in the 1990s, Li-ion batteries function by discharging positive and negative lithium ions through an electrolyte, producing an electric current.
The off-highway sector is clearly on the path toward electrification. Decreasing battery costs and the expansion of Li-ion supply chain capacity are accelerating the adoption of electric vehicles (EVs). Research provider BloombergNEF reports that prices for battery electric vehicles (BEVs) crossed below the $100/kWh threshold for the first time in 2024, and battery demand across EVs and stationary energy storage is projected to grow at a rate of 53% year-on-year.
Material-handling forklifts offer one prominent example of increased electrification. By 2020, 69% of forklifts shipped within the US were electric. While the majority of electric forklifts in use today still rely on traditional lead-acid batteries, the market share for Li-ion models is growing rapidly due to reduced cost of ownership and improved operational efficiencies.
Figure 1. A technician connects a high-power battery connector to a forklift during maintenance, highlighting the importance of durable charging solutions in material handling environments.
Electrification is also gaining traction in the ground support equipment (GSE), construction, and agricultural sectors. Electric GSE is quickly gaining ground as airports look to reduce their carbon footprint. New construction equipment — such as electric excavators, cranes, and light towers — offers advancements in noise reduction and fast charging. In agriculture, the shift is slower because farmers require heavy-duty electric equipment that can perform all day on a single charge.
However, the momentum is building. More farmers are adopting next-generation equipment, such as electric tractors and crop-spraying drones. Beyond the shift toward electrification, Li-ion batteries bring several practical advantages over traditional technologies.
The Li-ion advantage
One significant reason behind the growth of Li-ion batteries involves the technology’s inherent operational convenience. Traditional lead-acid batteries require long charging and cooldown cycles (often up to eight hours each) and should be fully discharged before recharging. Partial recharging can lead to adverse effects, including shortened battery lifespan and increased maintenance needs.
These constraints lead to additional labor and infrastructure costs. Equipment operators must frequently swap discharged lead-acid batteries with fully charged ones, often at inconvenient times, such as the middle of a work shift. To facilitate these swaps, owners must also purchase extra battery inventory and employ trained technicians onsite.
In contrast, Li-ion batteries support opportunity charging or charging at any moment of downtime, regardless of the remaining charge level. Li-ion batteries’ charge can be topped off in quick bursts during employee breaks or shift changes, providing equipment with enough power to last throughout the workday.
Therefore, opportunity charging eliminates the need for time-consuming battery swaps.
Li-ion batteries also facilitate easier and quicker charging. Equipment operators can plug in their equipment to charge with no trained technicians required. Since lithium-ion batteries charge faster than their lead-acid counterparts, Li-ion equipment can get back to work more quickly. Reducing downtime is particularly crucial for the ground support equipment industry, where quickly returning to work is essential in busy airport operations.
Charging convenience is a primary factor driving the shift from lead-acid to lithium-ion batteries. However, other Li-ion performance advantages over lead-acid and ICE-powered equipment include:
- Higher energy capacity: Lithium-ion batteries provide roughly three to ten times more usable energy capacity than lead-acid models. They also offer higher energy density.
- Improved durability: lithium-ion batteries can withstand more charge/discharge cycles and maintain more consistent performance over time compared to lead-acid batteries. Lead-acid batteries tend to degrade more rapidly and charge more sluggishly toward the end of their life cycle.
- Less maintenance: although lead-acid batteries are less expensive to purchase and install than Li-ion batteries, they’re often more costly to maintain over time due to their regular watering and cleaning requirements. A recent industry study found that Li-ion batteries have a lower life cycle cost than lead-acid batteries, primarily due to their extended lifespan, higher capacity, and reduced maintenance needs. In general, electric equipment is also easier to service than ICE-powered equipment because fewer fluids, oils, and coolants are involved in its operation.
- Quieter operation: compared to ICE vehicles, battery-powered equipment produces significantly less noise while operating. This is a particular advantage in construction environments where local noise restrictions are in place.
- Zero emissions: Li-ion systems eliminate concerns associated with indoor exhaust emissions. ICE vehicles can emit harmful gasoline or diesel emissions that require ventilation systems to process if used indoors. Zero-emission electric equipment avoids the hassle and the expense of installing such systems.
One ongoing challenge with lithium-ion technology involves its complex recycling process. The rare minerals within Li-ion batteries require specialized processes to break down. In response, different countries are investing in more recycling facilities. The US Department of Energy recently passed a bill that earmarked $335 million for lithium recycling.
How electrification is advancing sustainability
An additional advantage of lithium-ion batteries involves their environmental benefits. Sustainability is of particular concern to the ground support equipment market, which includes the equipment that supports airport operations. This includes applications such as electric belt loaders, tugs, pushback vehicles, boarding bridges, and de-icing vehicles.
Reducing emissions is a key pillar of many airports’ goals for the future. Aviation accounts for approximately 2.5% of the world’s CO2 emissions, and airports are strategic, single-point sources of emissions well-suited for sustainability initiatives. More than 300 airports across 32 European countries have already committed to achieving net-zero carbon emissions by 2050. Many other airports worldwide have adopted similar resolutions to reduce their carbon footprint.
Figure 2. Battery-electric ground support equipment, such as cargo loaders, are helping airports reduce emissions while introducing new demands for connector performance in harsh conditions. Stay tuned for Part II of this article, which explores how advanced connector designs support safety, durability, and high-voltage system integration.
To achieve more sustainable operations, increasing numbers of airports are making the switch to electric ground support equipment (eGSE). A recent European study found that electric GSE reduces CO2 emissions by 48% compared to GSE with traditional internal combustion engines. Electric GSE equipment also helps airports meet local air quality standards and reduces the health risk of emissions to airport workers and nearby communities.
Government policy is also incentivizing this shift, particularly in the airport and transportation sectors. In the U.S., the Federal Aviation Administration’s Voluntary Airport Low Emissions (VALE) program helps airports fund the purchase of low- and zero-emission vehicles and charging infrastructure. Since 2021, the EU has granted over €1.3 billion (approximately $1.4 billion) to several projects that electrified ground operations in 63 airports.
Broader sustainability regulations are also impacting the entire off-highway market. The EU has announced a total ban on the sale of internal combustion engine (ICE) vehicles by 2035, a significant step toward its goal of being completely carbon-neutral by 2050. Thirteen of the top 15 original equipment manufacturers (OEMs) in Europe have already announced they will ban ICE vehicles to achieve their emission-reduction targets.
Summary
As more equipment owners transition to lithium-ion systems for their superior efficiency, lower maintenance, and sustainability advantages, engineers must also reconsider the components that enable reliable, day-to-day operation. From opportunity charging to lower total cost of ownership, the shift to Li-ion is accelerating across off-highway applications.
In the next part, we’ll explore the specific connector requirements for outdoor charging infrastructure and how features like IP68 sealing, contact temperature sensing, and advanced signal capabilities are helping engineers meet the evolving demands of Li-ion electrification.
