Electric forklifts and industrial trucks rely on powerful batteries. But not every forklift battery is the same.
Differences in structure and cell chemistry have a direct impact on performance, charging behavior and service life.
In this article, you will learn how forklift batteries work, which technologies are used, and what you should pay attention to when selecting and operating them.
How is a forklift battery constructed?
A forklift battery generally consists of several battery cells connected in series or parallel to achieve the required nominal voltage. Each of these cells contains an anode and a cathode floating in an electrolyte. Through an electrochemical reaction, chemical energy is converted into electrical energy, which then powers the forklift.
The most important components of a forklift battery:
- Battery cells: Each cell has a voltage of approximately 2 volts.
- Electrolyte: Depending on the battery type, it consists of sulfuric acid, nickel-cadmium or lithium-ion compounds.
- Separators: They prevent a short circuit between the two electrodes.
- Housing/tray: Robust, often acid-resistant material protects the battery from external influences.
Which types of batteries are used for forklifts and industrial trucks?
Forklift batteries come in a variety of technologies, each with its own advantages and disadvantages. The most important types are:
Lead batteries
Lead-acid batteries are the most commonly used batteries in forklifts and industrial trucks. They use diluted sulfuric acid as an electrolyte and consist of cells connected in series.
Advantages
- Cheap to buy
- Robust and proven technology
- High capacity for long operating times
Disadvantages
- Long charging times and no quick recharging possible
- Regular maintenance required (e.g. refilling water)
- Self-discharge during prolonged non-use
Nickel-cadmium batteries
Ni-Cd batteries have a higher cycle life than lead batteries and are significantly less sensitive to temperature. They consist of a cadmium anode and a nickel oxide hydroxide cathode.
Advantages
- High energy density and long service life
- Temperature-resistant and work reliably even under extreme conditions
- Fast charging and intermediate charging possible
Disadvantages
- More expensive than lead batteries
- Contain cadmium, an environmentally critical heavy metal
- Memory effect can reduce capacity over time
Lithium-ion batteries
Li-ion batteries are a relatively new technology in the world of traction batteries. They consist of several electrochemical cells that convert electrical energy into chemical energy and are particularly efficient.
Advantages
- Maintenance-free and no water refilling required
- Fast charging and no memory effects
- Higher efficiency and longer lifespan than conventional batteries
Disadvantages
- Significantly higher acquisition costs
- Limited cell voltage, requires precise battery management
How does a battery work in a forklift or pallet truck?
The operation of a forklift battery is based on a simple principle: During charging, charged electrons are absorbed by the cathode and converted into chemical energy. When discharging the battery, the process is reversed: The stored chemical energy is converted into electrical energy and powers the forklift or pallet truck's motor.
Important aspects of how it works:
- Series or parallel connection of the cells determines the capacity and nominal voltage.
- Separators ensure that only ions, not electrons, flow between the electrodes.
- During charging and discharging, chemical processes occur that vary depending on the battery type.
How does the structure affect the performance of a forklift battery?
The design of a forklift battery determines how much electrical energy it can store and release. The key factors here are the number and arrangement of battery cells, the choice of electrode materials, and the type of electrolyte.
- More cells in series connection = higher nominal voltage (e.g. 24V, 48V or 80V).
- Cells connected in parallel = larger capacity, but same voltage.
- Electrode materials such as lead or nickel-cadmium influence the charging capacity and service life.
- Separators and housings must be permeable to ions but stable against chemical reactions.
A well-thought-out design ensures stable power output, efficient charging and discharging, and the longest possible use without loss of performance.
Why do forklift batteries differ in their design?
The structure of a forklift battery varies depending on the technology and intended use. Lead batteries, for example, require a liquid electrolyte, while lithium-ion batteries have a more solid cell structure.
Differences in construction
- Lead batteries → Liquid electrolyte, must be regularly refilled with distilled water.
- Ni-Cd batteries → Robust construction, resistant to high ambient temperatures, but with memory effect.
- Lithium-ion batteries → More compact, lighter and maintenance-free, but more expensive to purchase.
Depending on the requirements for capacity, charging times, and maintenance, a certain design is more suitable. The battery design is therefore always a compromise between performance, cost, and handling.
What role do materials play in forklift battery construction?
The choice of materials significantly influences the performance and durability of a forklift battery. The metals in the electrodes and the electrolyte, in particular, determine how efficiently chemical energy is converted into electrical energy.
Anode and cathode
- In lead batteries, the anode is made of lead and the cathode is made of lead oxide (metal oxide).
- Nickel-cadmium batteries use a cadmium anode and a nickel oxide cathode.
- Lithium-ion batteries rely on modern metal compounds with high energy density.
electrolyte
- Lead batteries use a sulfuric acid solution that moves ions during charging and discharging.
- Nickel-cadmium batteries use a basic solution as an electrolyte, which ensures low self-discharge.
- Lithium-ion batteries contain an organic electrolyte mixture that enables particularly fast charging.
Depending on the composition of the accumulator, a battery cell can store more or less electrical energy, which affects the nominal voltage and service life.
Why is the negative terminal crucial for battery efficiency?
The negative pole (anode) plays a central role in the electrochemical reaction of a forklift battery. During charging, electrons are added, while during discharging, they are released to supply the forklift with electrical energy.
Important processes at the negative pole
- In lead batteries, the negative pole is made of pure lead, which reacts with acid when charged.
- The cadmium metal contained in Ni-Cd batteries ensures a long service life.
- In lithium-ion batteries, the negative pole is made of lithium metal compounds, which enable a particularly high energy density.
A well-chosen metal on the negative pole determines the capacity, the discharge rate and the number of possible charges of a forklift battery.
What temperature conditions affect battery operation?
The ambient temperature plays a major role in the performance and service life of a forklift battery. Extreme cold or heat can slow or accelerate the chemical processes in the battery.
High temperatures
- Accelerate the chemical reaction, which leads to higher capacity but also faster wear.
- Can cause the electrolyte mixture to decompose.
- Increase the risk of overheating and possible damage to the battery cells.
Low temperatures
- Slow down the movement of ions, which slows down the discharge of the battery.
- Lead batteries lose power faster than Ni-Cd or Li-ion batteries because the liquid electrolyte carrier reacts.
- Nickel-cadmium batteries are particularly insensitive to temperature and work reliably even under extreme conditions.
How does the separator influence the battery structure?
An often overlooked but crucial component of a forklift battery is the separator. It ensures that the two electrodes do not come into direct contact, allowing only ions to pass through.
Functions of the separator
- Prevents short circuit between anode and cathode.
- Is permeable to ions, but not to negatively charged electrons.
- Influences the self-discharge of the battery because it regulates the flow of ions.
Depending on the battery type, separators are made of different materials:
- Lead batteries use plastic separators that remain stable in sulfuric acid.
- Ni-Cd and lithium-ion batteries use special polymer-based separators that are particularly resistant.
The quality of the separator is an important factor for a long service life and consistent power output of the forklift battery.
Conclusion: The right battery technology for maximum performance
The design of a forklift battery is crucial for its performance, service life, and efficiency. Each technology has its own strengths and weaknesses: Lead-acid batteries are inexpensive and proven, but require regular maintenance. Nickel-cadmium batteries are less sensitive to temperature and operate reliably even under extreme conditions, but they suffer from the memory effect. Lithium-ion batteries offer high energy density, fast charging times, and are maintenance-free, but with higher initial costs.
A sophisticated electrochemical design ensures the most efficient current flow from the anode to the cathode. The choice of electrolyte, the electrode material, and the number of battery cells connected in series are crucial factors, which determine the nominal voltage.
Modern batteries are made of specially developed conductive materials that optimize the chemical reaction between the cathode and anode. While primary batteries, such as zinc-carbon or alkaline-manganese batteries, must be disposed of after a single use, forklift batteries are designed as accumulators that can be recharged repeatedly.
Ultimately, the choice of the right forklift battery depends on the specific application. Those looking for a long-lasting, low-maintenance solution should opt for lithium-ion technology. Those seeking a proven and cost-effective option should stick with lead-acid batteries. The key is that the battery's design is precisely tailored to the forklift's requirements and operating conditions.
