Secure Battery Production for Electronic Cars with Fiber Lasers

The automotive industry is facing rapid change with the switch from internal combustion engine (ICE) vehicles to electric vehicles (in the form of all-electric, hybrid and hydrogen fuel cell models). This rapid change is bringing unique challenges to vehicle manufacturers, not only in the quality of production, but also the quantity required to meet immense consumer demand. SPI Lasers sell a range of Pulsed and CW fiber lasers, which are ideally suited to automate and deliver many of the tasks required for the high-volume production of batteries for electronic cars.

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Toyota Mirai electric battery and hydrogen pack

Advances in battery technology required

Further advances in technology will be required to improve reliability, lifespan between charges and reduction of costs (to be competitive with ICE battery costs) for producing Lithium-ion batteries for electric vehicles. The battery industry has used these types of batteries for years in laptops and cell phones, but electric vehicles require often in excess of 1,000 times more power. These batteries have to endure in various climatic conditions (e.g. heat and cold), as well as last for 10+ years (ideally), whilst starting every time!

Scaling up new battery technology production is a real challenge

As well as addressing the technology challenge, another major hurdle facing the industry is the rapid rise in demand for electric vehicles, for which there is often minimal existing manufacturing infrastructure. Vehicle manufacturers have been fine in manufacturing smaller numbers of electric vehicle units, but making these by the million is a new and exciting challenge, which we summarise below:

Electric vehicle worldwide population statistics over the past 5 years have been, Source: EV-Volumes:

  • 2018 – 5.4 million
  • 2017 – 3.3 million [Backed up by: T&D World]
  • 2016 – 2.04 million
  • 2015 – 1.25 million and
  • 2014 – 0.74 million

So, over the period 2014 through to 2018 we have already seen a 630% increase in electric vehicle populations! But we haven’t seen anything yet, as projections are suggesting:

Projections for electric car worldwide population, standard and high take-up models

Projections for electric car worldwide population, standard and high take-up models

Projections for electric car worldwide population, standard and high take-up models

Extracting from the chart above from the International Energy Agency (IEA), forecast worldwide electric vehicle populations are summarised:

  • 2020 – 20 million to 25 million
  • 2025 – 50 to 90 million
  • 2030 – 125 million to 225 million

The IEA has 2 models, one which is their expected progression based on current trends and government policies. The second is aggressive and assumes progression at its highest and based on major adoption.

With a growth in worldwide electric vehicles population from 0.74 million electric vehicles in 2014 to between 125 and 225 million by 2030 one thing is for sure, there will be at least a 150x increase in demand for electrical vehicle components, including batteries!

Batteries need to be of extremely high reliability and also rapidly produced. Manufacturing needs to change quickly, one tool for certain which can massively help with the high-volume manufacturing of batteries for electric vehicles are fiber lasers.

The three components of an electric vehicle battery

An electric vehicle battery is a form of energy storage device, which is specifically designed to work in electric vehicles. The electric vehicle battery is formed of three main parts:

  • Battery cells – these are assembled to become battery modules
  • Battery modules – the battery modules are then assembled into battery packs
  • Battery packs – the finished battery packs are then assembled into the electric vehicle

We expand on the above three components in the section below and advise on how fiber lasers are an effective solution in these areas of battery manufacture.

1)    Battery cells

Battery cells manufacturing offer many opportunities for fiber lasers including cleaning, cutting, drilling and welding, we explore these below.

Electric vehicle battery cells are currently Lithium-ion based, these consist of built up layers of coated aluminium and copper foil which are layered together with graphite (anode) and lithium metal oxide (cathode). Laser-cutting is ideal to cut the foils as it’s a non-contact process and also as the foils are very thin (c100 microns). Next liquid electrolyte is added and then the battery cell can be weld sealed with a cap and valve. This is where precision is required, as the welding must adequately seal the battery cell, whilst not penetrating so deeply that the battery cell itself is damaged (possibly beyond repair). Fiber lasers are ideal for this type of precision welding.

Coated aluminium and copper foil, as used in electric vehicle batteries

Coated aluminium and copper foil, as used in electric vehicle batteries

1)    Battery modules

Battery modules are formed by the grouping of typically up to twelve battery cells. Battery modules work by inter-connecting the cells together to perform as if “one unit”. Inter-connectivity is achieved through welding very thin sheets (often called tabs) of aluminium or copper to each cell. These sheets carry electric current supplies both out of and into the battery cells. Fiber lasers can be used to precisely weld to the required depth, which maximises the flow of electricity and in turn the battery charge.

The busbar works similarly for connecting all the battery cells together within a module and actively collects the current.

This process can be automated into manufacturing assembly lines with many battery cells being welded into modules every minute, all with absolute precision in a no-contact process of low risk to humans. This most often involves the welding of aluminium and copper, which poses its challenges as these are dissimilar metals and also both highly reflective. SPI Lasers patented back reflection technology is ideal in preventing reflection, and fiber lasers in general are ideal for welding busbars within battery modules and overcoming the challenges of welding dissimilar metals.

Electric cars will play a significant part in creating a green friendly future

Electric cars will play a significant part in creating a green friendly future

1)    Battery packs

The battery pack is the third and final stage, where the self-contained battery modules are sealed within the final battery pack. It is the battery pack, which actually ends up installed within the electric vehicle, as with fuel tanks, the battery pack needs to remain in place under all driving conditions including crashes.

Typical metals within battery packs include:

  • Aluminum alloys
  • Aluminum to copper
  • Aluminum to nickel
  • Copper
  • Copper to stainless steel
  • Copper to pure nickel and
  • Nickel coated steel

Given the production volumes of these batteries, the high-quality, repeatable functionality of fiber lasers where human errors are removed is of great value. The programmability of fiber lasers will help in the welding of various thicknesses and material types, which can vary considerably.

Battery pack welding in general can be considered quite complex in that usually highly-conductive and reflective (often dissimilar) metals such as copper and aluminium need to be joined.

The pack is welded underneath the body of the vehicle and is located close to the road surface. There will literally be hundreds if not thousands of individual battery cells, which will form the battery pack. Therefore, the welding joints need to be of high-quality, reliable and absolutely precise in sealing to prevent:

  • Battery chemicals dripping out of the battery pack onto the surface below and
  • Water and dirt from penetrating inside the battery pack

The battery pack is usually glued in place (rather than welded), to allow later re-opening. Fiber lasers play an important role here too through cleaning and surface preparation techniques to ensure the glue absolutely adheres.

Fiber lasers will also be of high value in welding battery packs for special models, country variants and any other type of short run.

Qualities which fiber laser welding gives to battery packs are:

  • Gives excellent static and fatigue strength
  • Provide excellent electrical contact resistance to avoid efficiency power losses at each joint
  • Eliminates mechanical approaches (e.g. nuts and bolts), which add weight, extra complexity, cost and reduce long-term reliability
  • The entire process is no-contact, which reduces contamination and risk to human operators

Please read our detailed guide to tab welding and Bus Bar welding of battery packs here.

Frequently asked questions about batteries in electronic cars

We realise that consumers have many questions about batteries in electronic cars, so we have answered a few in the section below?

1)    Will batteries require extra space in electronic cars?

It’s true that batteries require space, but most batteries are integrated well so as to maximise the available space. In many cases space savings will arise as there will be no need or reduced need for fuel tanks (as needed in ICE cars).

1)    Can batteries be recycled in electronic cars?

Due to the amount of precious materials within Li-ion batteries, attempts will always be made to recycle. Currently, the costs are quite high, but as electronic cars become more popular the costs will reduce (as Li-ion batteries increase in popularity). Similarly, the rise in popularity of e-vehicle batteries is likely to create innovations in recycling, as “necessity is the Mother of invention”.

Batteries can also be converted into energy storage devices, which is another way of extending the lifespan of a battery.

SPI Lasers – developing solutions for e-mobility

Undoubtedly, e-mobility will not thrive without advances in battery technology and capabilities. SPI Lasers are working hard with our Pulsed and Continuous Wave fiber laser models to advance the batteries market through the development of cutting-edge manufacturing solutions in this industry. If you have battery requirements for e-mobility projects, then why not contact SPI Lasers?

An electric battery installed inside a car

An electric battery installed inside a car

Image Credits: Wikipedia, Geralt and Kaboom Pics

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