Energica motorcycle battery housing

Energica motorcycle battery housing
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Energica motorcycle battery housing: A major technical component created through CRP Group’s innovative technology

At the heart of Energica motorcycles lies the battery case. It is the technical component that contains all the rechargeable batteries.
The battery case is a sealed housing that holds battery cells, the Battery Management System (BMS), and all the necessary provisions to ensure the safety of the vehicle. The battery case keeps all high-voltage components encapsulated, making it unlikely to accidentally be exposed to damage.
Usually the batteries contained in this component warm up: the heat produced dissipates only minimally.
In the Energica motorcycles, heat develops especially when a lot of power is required (during the acceleration phase) and when they are rapidly recharged (Fast Charge).
Energica’s battery case has been designed to avoid overheating of the batteries during these phases.
The battery case is an “intelligent” device with its own electrical brain, comprising dozens of sensors and electromechanical devices that constitute a closed subsystem to ensure maximum vehicle performance and driver safety in all environmental conditions.
Energica has designed a passive air cooling system for the battery case that is superior thanks to its specific ventilation paths that limit heat stress on the batteries. This provides considerable benefits to both performance of the vehicle and battery life.
The battery case includes an aluminum cooling plate (the “central septum”). It conveys the incoming air and facilitates heat dissipation.
Energica is the only company in the world that has designed, patented and adopted this type of technology on its own bikes.

The battery housing and the central cooling septum are excellent examples of the advanced engineering CRP Meccanica has developed over 45 years of experience in general Motosports, F1 and demanding sectors that require state-of-the-art customized technology.
CRP Meccanica is the CRP Group’s leading company in the field of high precision CNC machining and cutting-edge technology.

Battery housing (setting-up phase)

Battery housing (setting-up phase)

The object of this case study is the creation of the Energica Ego battery housing.
Team Energica took advantage of the support and expertise of CRP Technology, the CRP Group company leader in the field of professional 3D printing with Windform® composite materials, and CRP Meccanica as well.

Energica and CRP Technology worked together to redesign the battery housing.
The redesign was necessary to meet two specific needs: space containment and cell cooling.

The prototyping phase: First step. Creation of the functional prototype via professional 3D printing

The decision to opt for the creation of a functional 3D printed prototype via Laser Sintering technology using Windform® LX 2.0 composite material. That is the result of a process undertaken by CRP Technology together with the Energica Motor Company team engineers.
Windform® LX 2.0 is a composite polyamide-based material which is reinforced with a new generation glass fiber, now replaced by its technical evolution, Windform® LX 3.0.

The prototype was built in one of the large frame systems available at CRP Technology, which has maximum working dimensions are 550X x 550Y x 450Z mm.
This is noteworthiness, as it is difficult to find a 3D printing service able to guarantee the manufacturing of such large pieces.

3D printed functional prototype in LS technology and Windform LX 2.0

3D printed functional prototype in LS technology and Windform® LX 2.0

3D printed central septum

3D printed “central septum”

The mechanical characteristics of the Windform® LX 2.0 composite material (high level of temperature resistance, not electrically conductive) in addition to the peculiarities of the LS technology, it allowed the manufacturing of a high-performance functional component.
Thus, the Energica staff was able to directly perform the R&D and testing phases on the Windform® 3D printed prototype, in order to shorten design and product development activities.

Detail of manual sanding/de-burring on the 3D printed prototype in order to fit it

Detail of manual sanding/de-burring on the 3D printed prototype in order to fit it

Detail of the Aluminum cast battery housing: the area has been profiled and adapted

Detail of the Aluminum cast battery housing: the area has been profiled and adapted

The prototyping phase: Second step. Creation of the CNC machined Aluminum rapid casting component

In the second step of the prototyping phase, the Energica battery housing was made up of two shells manufactured in Aluminum rapid casting and then CNC machined.

In this phase, the CRP Group developed a working method that was then applied to the entire production system.

the CNC machined Aluminum rapid casting component

the CNC machined Aluminum rapid casting component

CRP has worked closely with the foundry chosen by Energica for the creation of the CNC machined Aluminum rapid casting prototype, yet another example of rapid prototyping.

“We also used process simulation programs to study the behavior of the casting flow. In this way we were able to prevent and limit issues, and ease manufacturing of the component”.

The battery housing is one of the most difficult structures to melt because it tends to distort and to complicate subsequent mechanical processing.
To avoid these issues, we modified the geometries of the component and developed a shape that would be stable and rigid during processing phases.
The manufacturing process we refined, was transmitted to the foundry, which was able to realize the component without incurring unpleasant surprises.

detail of the manual finishing to refine CNC machined areas

3D printed Windform® LX 2.0 functional prototype – detail of the manual finishing to refine CNC machined areas

CNC machined Aluminium rapid casting component– Detail of the CNC machined part

CNC machined Aluminium rapid casting component– Detail of the CNC machined part

No other supplier has succeeded in what CRP has done – Energica staff commented -. We asked the CRP staff for the impossible and … they made it possible, respecting high level precision requirements. The staff of CRP has obtained very tight tolerances, perfectly in line with our requests and needs”.

Third phase: industrial production of the component via sand casting process

In the third phase, the industrial production, the component was manufactured by traditional sand casting process, with the same alloy used in the second phase, taking advantage from the previous experience.

“It represents a precise choice – CRP team added – during the phase 2 not only the CNC machined Aluminium rapid casting functional prototype was manufactured, but we also developed the process parameters to be used in the last and third phase.
This allowed us to approach the last phase in total safety; in fact, we did not find any issues or unexpected problems during the production of the battery housing.”

For this reason, phase 2 is to be considered very important.

Aluminium cast battery housing ready to be mounted on Energica's bikes

Aluminium cast battery housing ready to be mounted on Energica’s bikes

Detail of the battery housing (setting up phase)

Detail of the battery housing (setting up phase)

It is very interesting to notice the “sui generis” solution to enclose the cells inside a metal battery housing manufactured via rapid casting.
By experiences gained in the field of electric racing and by few examples of electric motorcycles currently on the market, CRP has noticed that the battery housing is often manufactured using composite material. It caused several issues:

  • Safety wise, in terms of electrical conductivity: composite materials, if reinforced with carbon fiber, tends to be slightly conductive and since there is a high-voltage electrical component inside, it can be dangerous.
  • in terms of road safety: when one falls off a motorcycle, the composite material, if not structural, does not guarantee adequate protection. The Energica staff, supported by CRP, has sized the aluminum casting battery housing in order to cope with issues caused from any falls of the motorbike during the ride, ensuring maximum safety for the rider and for the rescue personnel

EMI source and the EMC testing

All vehicles, vehicle parts, and electronic products for vehicles must be subject to EMC testing prior to their commercialization.
In all Energica motorcycles the Battery Management System (BMS) is contained in the sealed metal battery housing: thus, the component is protected against electromagnetic radiation.
By manufacturing the battery housing via sand casting process with metal, Energica has successfully passed all EMC tests right away.
The battery housings made of composite materials, on the other hand, must be submitted to a preliminary screening operation, which leads to high costs and extended handling times.