Desoutter Assembly Solutions for Electric Vehicles

The electrification of internal combustion engines (ICE) vehicles, to be fully or partially replaced by an electric powertrain, leads to new assembly challenges. These include among others new tightening applications in different environments, higher levels of automation and requirements on traceability, but most importantly higher safety standards for operators during the assembly of components with high-voltage contact. 

Integrated Manufacturing has supported the electric vehicle industry for 10+ years and have continued to provide manufacturers with solutions to their problems in any capacity. By working closely with our customers along with providing them with the technology and tools they need to do a more efficient job we’d like to provide some more information on how we can help your process. 

Connectors

Electric vehicles have a large amount of electrical components compared to ICE vehicles, such as chargers, DC/AC inverter, DC/DC converter, battery pack etc. Numerous connectors are required to connect these electrical components.

Some challenges that you could have with installing a connector are:

• Operators need flexibility to hold connectors while tightening.
• A large area to cover due to size of the battery pack or distance between different components.
• Plastic material can be easily damaged during the tightening process (particularly during high speed assembly).
• Safety-critical applications (class A joints).

We have a solution to all of these problems and can help with ensuring that the process is done correctly and efficiently, with a wireless transducerised battery tool or BLRT, EABCom, or EPBCom. Some positives to using these tools include:

• Battery pistol/one hand tool (i.e. EPBC/EABS range)
• Tool can be operated by only one hand while the other is free to hold the connector
• Increases operator’s flexibility as no cable restricts movement area
• Multi-step tightening program to avoid damage of plastic component while keeping high tact time
• Advanced tightening strategies to ensure zero-fault and full traceability

Busbars and High Voltage Harnesses 

High voltage harnesses connect the battery pack, DC/AC inverter and motor in electric vehicles, but also battery components within the pack such as different modules. To save space in the narrow battery pack, copper busbars are frequently used for electric vehicles.

These high voltage harnesses and busbars are charged with high current and voltage loads (rf. 800V). Manufacturing operations under high voltage conditions require special safety measures for operators as risks are high on these applications.

Some challenges that you can have with busbars and harnesses are:

• Electric vehicles have significantly higher voltages (up to 800V DC) and accidental contact with an energized source from these vehicles can be fatal.
• Operators who will be coming into contact with live circuits when working on EV’s can be at risk of electric shock, which can result in serious injury or death.
• Identify the positioning of the busbars and ensure the order of the tightening sequence
• Safety-critical applications (class A joints).

We can provide a solution to these issues in the form of tools designed to deal with high voltage and prevent injury from working with live circuits. Some of these tools include the IEC 60900 and IEC 60664 which have insulated rubber covers and protection. These tools have also been tested and approved by DEKRA. Some more positives include:

• During the assembly of components exposed to high voltage such as busbars and harnesses, using insulated tools is one of the many important steps to protect from electrical shocks and damages:
• the operators
• the tools
• the battery pack
• the assembly line
• Insulated tools and isolated sockets are designed to protect the operator in the event that they touch an energized source, such as the high voltage components (i.e. battery modules) and cabling of an electric vehicle.
• The design is following strictly the requirements of the latest International Electro technical Commission (IEC) norms IEC60900:2018 & IEC60664-1:2020 that entails to ensure operators are protected against electrical breakdown for currents less than 1000V/AC and 1500V/DC.
• Real time process monitoring and guidance with conventional or advanced positioning guide solutions to ensure sequenced tightenings for total quality control.

Module Assemblies and Battery Packs

A module assembly is a battery assembly put into a frame by combining a fixed number of cells to protect cells from external shocks, heat or vibration.

The assembly of the battery modules requires moderate tightness, and each structural component requires sufficient strength to prevent deformation or damage from external force of the battery.

Battery packs consist of several hundred cells. Each cell is delivered with at least a minimum state of charge. When connecting, the voltage can become a hazard for the worker. Simply put, cells, modules and packs are units of gathered batteries. A cluster of cells make up a module and a cluster of modules make up a pack.

Some challenges that you can have with module assemblies are

• High cycle time is requested for Module assembly
• Ensure that the modules are mounted with an adequate clamping force.
• Critical process steps that require full traceability and quality control to avoid re-work.

Some challenges that you can have with battery packs are

• Frequently, long screws are applied to tighten the modules and fix the modules on the battery pack tray.
• The assembly of modules into a battery pack are frequently highly automated (short takt time with large quantity of modules, high weight of modules, no risk electric shocks to operator) and require automatic tightening and screw-feeding solutions with long screws and high torque.
• Integration of modules are critical and require full traceability and quality control to avoid rework.

We can offer custom solutions to these issues, some of them can include a step feeder system and bowl feeder system working in tandem with your tools and manufacturing process. Another option is a multi spindle system. These options are all designed to be integrated into an automation setting. There are a large variety of these options from us and they have the following capabilities and features:

• Advanced multi-spindle solutions for the shortest takt time
• Highly integrated tightening and screw-feeding system
• Customized screw step feeder system for long module screws
• Our advanced controller solutions guarantee 100% traceability and can be easily connected to higher level systems.

Upper Cover for Battery Packs

One of the final manufacturing steps for the battery pack assembly is the fastening of the upper cover on the tray, to close and seal the entire battery pack. Typically, tightening applications are used to control the clamping force and to improve serviceability of the battery pack. In order to protect the inner part of the battery from moisture and to also avoid exposure of hazardous gasses or liquids from the inner part, a sealant is applied between cover and tray.

The challenges faced with installing the cover can be

• Due to the large size of the battery pack a large quantity of screws need to be fastened within a short time.
• The screws need to be tightened in a sequential order to ensure a uniform clamping force on the battery pack.
• Different tightening behaviors between the upper cover and tray can affect residual torque because of the sealant material (i.e. rubber material).

With a screw feeding and customized positioning system it can make it easier to apply and work with attaching the cover to the battery packs. These options can work together and reduce accidents from occuring, ensuring screws are tightened properly, and making sure everything is held in place.

• Conventional or advanced positioning guide solutions to ensure sequenced tightenings for total quality control.
• Automatic screw feeding systems to boost productivity.
• Advanced tightening strategies and multi-step tightening program to ensure uniform clamping force and distribution of sealant.

Electric Motor and Transmission

The electric motor drives the vehicle's wheels by using power from the battery pack. Some vehicles use motor generators that perform both the drive and regeneration function. Usually, direct current (DC) electricity is fed into a DC/AC inverter where it is converted to alternating current (AC) electricity and this AC electricity is connected to a 3-phase AC motor.

The power produced by the electric motor (or ICE) is transferred to the drive wheel via a transmission system. Often referred to as a gearbox in internal combustion vehicles. Most electric cars use a single speed transmission, because the motor is efficient in a wide range of operating conditions.

Some challenges that you can have with the assembly process are

• High production rate.
• Uniform clamping force for best possible sealing of the motor and transmission system.
• Safety critical joints (class A-B).

By using a combination of different solutions the tightening and assembly process can be completely monitored to ensure excellent quality control in the end product. By using screw feeding systems, motion capture, and nutrunners you can ensure that the production is efficient and calculated. With these options and combinations you can choose something that works from you, they have these capabilities:

• Conventional or advanced positioning guide solutions to ensure sequenced tightening for total quality control.
• Advanced tightening strategies and multi-step tightening program to ensure uniform clamping force and distribution of sealant.
• Automatic tightening and screw feeding systems to boost productivity.
• We offer customisable multi spindle solutions (easy robotic integration) for short takt time applications.

Power Electronics

Inverter (DC/AC): Coverts direct current (DC) power to alternating current (AC) power. The inverter can change the speed at which the motor rotates by adjusting the frequency of the alternating current. Converter (DC/DC): This device converts higher-voltage DC power from the battery pack to the lower voltage DC power needed to run vehicle accessories and recharge the auxiliary battery. On board charger (OBC): The OBC takes the incoming AC power supplied via the charge port and converts it to DC power for charging the traction battery. Battery Management System (BMS): The BMS is controlling multiple functions vital to the correct and safe operation of the electrical storage system (e.g. temperature management, battery performance optimisation).

Some challenges that you can have with the electronics are

• Numerous components and complex assembly processes for operators.
• Printed circuit board (PCB) and cover screws need to be tightened in the right sequence.
• Accessibility issue due to the design of components with narrow inner parts.
• Safety-critical applications (class A joints).
• High production rate.

For occasions like this where delicacy is required we offer narrow space solutions so you can get into tight to reach spots, along with these tools you can have an insulated option so that no electrical issues can occur. In combination with our wireless pistols and positioning arms the information for each torque target can be accounted for and recorded for quality assurance. Depending on what you might need, there’s a solution for it and with each solution being compatible with each other the software that we can offer helps keep things streamlined and upgradable. 

• Advanced (digital) process control solutions with structured sequence of work instructions and visual guidance delivered to the operator. The benefits are zero-fault assembly and complete traceability of all process steps and fastening results available.
• Conventional or advanced positioning guide solutions to ensure sequenced tightening for total quality control. 
• For applications that are difficult to access, We offer different solutions depending on the customer’s needs: crowfoot, delta wrench or angle head tools.
• Automatic tightening and screw feeding systems to boost productivity.
• Advanced tightening strategies to ensure zero-fault and full traceability.

This page has information from the Desoutter catalog, Assembly Solutions for Electric Vehicles. While the base information was not written by Integrated Manufacturing, we can provide the solutions and assistance described in this post. If you would like more information please contact us and we’ll be sure to help!