batteries for industrial trucks

Electric pallet truck with lithium battery

Electric industrial trucks get their energy from batteries. This applies to vehicles such as forklifts or pallet trucks. In order to meet the special requirements of logistics, the rechargeable batteries have a specific structure.

Table of contents

Construction
function
traction batteries
types
Selection

Construction

Galvanic elements are used in electrically powered forklifts and pallet trucks . The battery consists of several cells connected in parallel. The capacity of the battery depends on the number of cells. The structure includes the following components:

Negative pole made of metal, the positively charged anode
positive pole made of metal oxide, the negatively charged cathode
an electrolyte as a medium for the ion flow
separator plate or separator

function

If the forklift needs energy, for example to lift the mast, the negatively charged electrons flow from the cathode through the electrolyte to the anode in the electrolysis process. They have to pass through the separator, which is permeable to ions. At the same time, however, it is not electrically conductive and thus prevents short circuits in the cells. During this process, the acid density in the battery drops and the cell voltage falls.

When charging, the acid density increases again because the electrons are released from the anode and the original charge gradient is restored. The electrochemical processes in the battery are therefore reversible. Recharging is done with direct current. Rectification is achieved by the battery charger transforming the mains voltage to the required battery voltage.

If the electrolyte is water-based, regular water refills are required. This involves a certain amount of maintenance work for the operator and the industrial trucks are not available during maintenance.

traction batteries

The batteries used in industrial trucks are so-called traction batteries. These differ in key features from conventional starter batteries, such as those used in cars or forklifts with combustion engines.

The following differences are evident:

Traction batteries have a higher mechanical stability of the cells.
Starter batteries are only designed to deliver large amounts of energy for short periods of time.
Traction batteries achieve a higher operating voltage by connecting the cells in series.
Traction batteries have a higher capacity.

types

In practice, different types of industrial truck batteries are available. The following are among the most common:

lead-acid batteries

In this model, the anode is made of lead and the cathode is made of lead oxide. Sulfuric acid diluted with distilled water serves as the electrolyte. It has the following properties compared to lithium-ion batteries:

inexpensive purchase
high performance
long loading times
low energy density
frequent water refills

lithium-ion batteries

Lithium-ion batteries can be found in many current forklift trucks. The electrolyte is water-free, the negative electrode is made of graphite, the positive electrode is made of metal oxide. This battery technology is characterized by the following features:

high energy density
long lifespan
short loading times
high efficiency
high purchase price

nickel-cadmium batteries

Nickel-cadmium batteries use a potassium hydroxide solution as a catalyst. The memory effect no longer occurs in newer generations. They serve as an alternative to lead-acid batteries, with the following differences:

higher charging and discharging currents
low self-discharge
suitable for intermediate loads (for industrial trucks in multi-shift operation)
less sensitive to temperature

lead-gel batteries

The lead-gel batteries have the special feature of being maintenance-free. The user does not have to refill water over the entire service life. By adding silica, the manufacturer ensures that the electrolyte in this battery is no longer liquid. Unlike wet batteries, the nominal capacity is only 60 instead of 80 percent.

Selection

Logistics companies are faced with the task of choosing the right battery technology to handle their transport tasks with industrial trucks . In high-performance intralogistics, lithium-ion batteries or nickel-cadmium batteries are a very good choice because their energy density and charging and discharging currents are suitable for the demanding application.

If the use of industrial trucks plays a minor role in a company, lead-acid or lead-gel batteries are suitable as inexpensive drive batteries.