The challenge for many manufacturers of Light Electric Vehicles is how to achieve high capacity and high power in combination battery swapping. Cleantron has developed a powerful, modular battery system: the High Power Multi Pack Configuration. The future for Light Electric Vehicles such as scooters and minicars begins with Cleantron HP MPC.
Electric driving is ‘in’, but is also in danger of stagnation. Many countries cannot sufficiently expand the charging infrastructure in urban environments. This impedes the further advance of e-mobility with electric vehicles and LEVs (Light Electric Vehicles). What’s more, interchangeable batteries are often heavy and difficult to handle, and their performance is often inadequate. Because of these factors vehicle manufacturers are limited in their sales opportunities.
Cleantron has therefore developed modular technology to increase capacity (Multi-Pack Configuration, or MPC) and generate more power (High Power MPC). High Power MPC is a groundbreaking battery system that can kick-start the transport energy transition.
Cleantron has years of experience with the development and production of 48V portable lithium-ion batteries. On the basis of this expertise a special team of engineers developed the High Power MPC system. This is an integrated system in which one fixed high-power lithium-ion battery-pack and one (or more) compact, high-capacity lithium-ion battery module(s) work intelligently together via a special unidirectional DC/DC converter with no loss of performance (range and speed).
To guarantee that the vehicle can both operate for long periods and accelerate well, the portable batteries provide as much energy (kWh) as possible while the fixed battery creates maximum power (kW). Both the portable battery component and the fixed battery can comply with the safety requirements of ECE R100 (electric vehicles) and NEN-EN 50604-1 (rechargeable lithium batteries for Light Electric Vehicles).
Cleantron has designed the portable component in such a way that as much energy as possible (1.4 to 2.4 kWh per battery) is generated by batteries that are as light and compact as possible. A vehicle compartment can contain several low voltage (less than 60V) battery modules or cartridges. The end user can therefore change the touch-safe battery modules with no risk.
The portable battery modules weigh less than 10 kg. and can be employed like a laptop. To achieve this low weight Cleantron limits the discharge power, so that lighter wiring and smaller connectors can be used and deterioration of the battery cells is limited.
The portable battery modules are switched in parallel using the Cleantron MPC system. This system controls the communication between the batteries, which for safety reasons all have their own BMS (Battery Management System). The MPC system determines which battery has to be activated on the basis of the charge status of the portable batteries, and seamlessly switches over to that battery. In principle, the number of battery modules that can be connected is endless: with the low weight of the portable batteries, the MPC system modular offers great flexibility.
The DC/DC converter allow that the – low voltage- portable battery modules charge up the High Power component of the system. A low, constant current flows from the portable battery modules to the fixed battery-pack via the converter. Because there are less current peaks, there is less warming and deterioration of the fixed battery, and this battery is used to the full. Cleantron offers a choice of three types of converters (48/48 V, 48/100 V and 48/400 V) for different power trains.
The following aspects play a role in the choice of the type of converter:
Cleantron can supply a low or high voltage battery-pack to match the powertrain in question and performance requirements. There is also a choice of different chemistries in line with their use, especially LFP and LTO (low voltage) and NMC and NCA (high voltage).
Every chemical composition has its own specific characteristics and performance in terms of energy density, capacity, safety, lifespan and costs (see spider diagram). LFP (Lithium Ferro Phosphate), and especially LTO (Lithium Titanate Oxide) chemistries offer a high power per battery cell, and can therefore remain a compact – and cost effective- component of the fixed battery.
In case of a low voltage High Power MPC system, the fixed battery can be executed in LTO. The LTO chemistry is characterised by a long lifespan, large temperature range and low cell impedance, which limits the heating of the cell. This minimal temperature development makes LTO batteries eminently suitable for high discharge currents in high ambient temperatures, without the need for active cooling. The chemistry of LTO also offers the advantage that batteries can be recharged below 0 degrees Celsius, so no heating is needed.
Due to the more attractive cost level, NMC (Lithium Nickel Manganese Cobalt Oxide) and NCA (Lithium Nickel Cobalt Aluminum Oxide) will be the candidate chemistries for larger, high voltage, HP MPC systems. Cleantron produces and supplies fixed batteries with a capacity of choice between 1 and 60 kWh. With so many options one can configure the optimal battery system, taking into account performance and service life.
The High Power MPC system offers vehicle manufacturers the possibility of combining portable batteries and a fixed battery in optimal application-specific ways. The system is particularly suitable for micro-mobility (two-wheeled vehicles such as electric motorcycles and scooters, and minicars), urban distribution (last mile cargo delivery), multi-person transport (taxis and minibuses) and maritime applications (dinghies, water taxis and motor yachts). By sharing ideas in a customer-oriented way Cleantron can design and build the ideal configuration for every application and operating radius.
Cleantron has simulated and accurately calculated various configurations of the High Power MPC system. Both when used in an electric motorcycle and in a small city distribution vehicle (for last mile delivery vehicle), the system appears to function very well.
The High Power MPC system never comes to a standstill during a journey because of the emptying of the fixed battery: the portable batteries make sure the fixed battery constantly has sufficient voltage by recharging it. The average usage of the vehicle (kW) is about the same as the recharging of the portable batteries.
During acceleration the charge status or SOC (State of Charge) of the fixed battery fluctuates, because the energy consumption of the power train is higher than the capacity of the DC/DC converter. The charge status stabilises at cruising speed, recovers during braking and while the vehicle is stationary. In this way the system guarantees a relatively stable charge status of the fixed battery. Eventually, when driving both the fixed battery and the portable batteries empty, this gives the following picture:
Figure 1a SOC of the fixed High Power Battery Pack over time.
Figure 1b SOC of the 2 portable Battery Modules over time.
Specifications of a High Power MPC system for an electric motorcycle:
World Motorcycle Test Cycle WMTC:
Figure 2 World Motorcycle Test Cycle (WMTC) at an average speed of 38.7 km/h.
The operating radius of an urban distribution vehicle can be increased with the use of portable batteries, matched to the required operating radius for the day in question.
The charge status of the fixed battery will slowly decrease (figure 3a), but is continually recharged by four portable batteries (figure 3b).
Figure 3b SOC of the 4 portable Battery Modules over time.
The fixed battery can also continue to be recharged while the vehicle is parked (without any charging infrastructure). That’s a major benefit. Of course it’s also possible to change a portable battery module while parked up, and to continue the route with fully charged portable batteries in order to make use of the maximum operating radius.
Specifications of High Power MPC system:
World Motorcycle Test Cycle WMTC: