Forklifts with Lithium-ion batteries in cold store: Is that a thing?

Lithium-ion battery technology fitted to your forklifts and warehouse equipment can be very beneficial for your intralogistics processes. It is energy-efficient, allows for opportunity charging and has no drop in performance. The question is if this is also true in temperature-controlled environments, for example in cold stores? Read how the performance of lithium-ion batteries can be maintained in cold conditions.

Frozen goods handling: time is critical

Li-ion batteries are a good solution for time-critical processes for instance in food logistics. In this industry we find the dry assortment, fresh goods and frozen goods. While the dry assortment is stored at normal room temperature, goods from the fresh assortment, such as dairy products, fresh meat or fresh fish and fruits and vegetables, must be stored at temperatures between 2 to 8 degrees Celsius. As a rule, these products have a short shelf life and must therefore be handled in the shortest possible time. Frozen food and ice cream are stored at lower temperatures of -18 degrees Celsius or even colder.

The challenge for forklifts in the cold

For storage and transport under these extreme conditions, dedicated forklifts and warehouse equipment with condensation protection is needed. Condensation is formed when trucks go in and out of the cold area. For the driver, heated cabins offer a more comfortable workspace.

The challenge for batteries in the cold

Lead-acid forklift batteries

Batteries discharge faster at low temperatures, losing power. In general, the lower the temperature, the lower the battery capacity. The capacity of a lead-acid battery is at its highest at an electrolyte temperature of 30 degrees Celsius; at an electrolyte temperature of -20 degrees Celsius, the available capacity drops to 55 percent. Charging also takes longer at low temperatures, because the battery absorbs the energy poorly and this even becomes impossible at sub-zero temperatures. Therefore, lead-acid batteries must be stored and charged at room temperature. For deep-freeze applications, therefore, two replaceable batteries, i.e. three lead-acid batteries per device, are usually required. In addition, the maintenance and care costs for lead-acid batteries in deep-freeze applications are higher, an example being the prevention of so-called creepage currents and attendant discharges, which favour the development of moisture and dirt on the surface.

Li-ion forklift batteries

What many fleet managers and operators do not know is that, even under extreme conditions, the use of lithium-ion batteries makes sense for several reasons:

• Higher energy efficiency and low CO₂ emissions
• Easy and safe handling
• Shorter charging times
• No replacement batteries needed
• Maintenance-free and no outgassing during charging or operation
• Guaranteed safe system with high availability
• Thermal management system monitors the temperature of each individual cell within the battery
• Availability of battery heating for continuous operation in cold store:
  • Battery heating integrated into each module and only activated when required protects the cells from cooling down
  • Lithium-ion batteries can be charged in the deep-freeze area as often as needed
    
    

Toyota’s Li-ion solution for cold environments

Our battery solution is specially designed to meet the needs of industrial trucks and is also available in a cold store version. The system offers a robust design, a high quality of the individual cells and modules as well as complex safety components. This means that every single module and the entire battery system are protected against dust and splashing water. The self-contained system is completely maintenance-free and does not release gases into the environment during charging or operation. This eliminates the need for extra ventilation of the loading area and operators do not have to fill up water nor handle acid.

Thanks to the protective cover and the heat generated during operation, the Toyota Li-ion batteries do not cool down quickly and keep performance standards, even at low temperatures. The standard Li-ion battery comes with a thermal management system that monitors the temperature inside the cells of a module. If a module inside the lithium-ion battery becomes too cold, the driver receives a warning message informing him to drive into a warmer environment. Consequently, the truck can be operated at -10 °C for up to 4 hours and at -30 °C for up to 2 hours. If the vehicle is to be used permanently in the cold store and even charged there, the cold store version with battery heater is available.

Our Li-ion solution is extremely energy-efficient. Only when a module falls below a certain temperature, the battery heating activates. This prevents the battery from getting too cold and thus losing capacity. This has a positive effect on availability and operating costs and increases the service life of the devices. Thanks to the thermal management and the battery heating, the forklift can constantly remain in the deep-freeze area, even at temperatures down to -30 degrees Celsius. The additional costs for the increased energy consumption are offset by savings due to the reduced wear of the battery and device.