The previous decade, the electrical car {industry} has witnessed developments in battery pack design influenced by progressive design traits. We discover the rising traits shaping the way forward for EV batteries for each mass-market and area of interest car purposes.
The not-so-humble battery is approaching 225 years outdated. Over its lifetime, its architectures have come a really great distance from its unique uncomplicated design. From Alessandro Volta’s rudimentary breakthrough in 1801, which noticed the world’s first battery encompass copper, cardboard, zinc, leather-based separators and, unbelievably, a conducting factor that was his personal tongue. Skip ahead to 1979, and the essential breakthrough of rechargeability for lithium-ion cell batteries, found by John B. Goodenough and Koichi Mizushima despatched the battery market skyward.
At the moment, the worldwide electrical car battery market is predicted to hit US$85.35bn in 2024 and is anticipated to succeed in round US$252bn by 2032. The automotive {industry} alone expects demand for lithium-ion cells to develop by 33% yearly, reaching 4,700 GWh by the top of this decade.Regardless of these early restricted capability batteries, evolving design has opened the door for industry-changing applied sciences, notably coming to fruition within the realm of electrical mobility as engineers proceed to create extremely developed applied sciences.
The early days of EV battery design
Reflecting on the battery designs for BEVs from only a decade in the past with the e-mobility market in its nascent levels, two distinguished fashions made a huge impact: the Nissan LEAF and the Tesla Roadster, every using distinct battery applied sciences. These early designs have been closely influenced by battery applied sciences from different industries. As an example, Tesla utilized cylindrical cells like these in energy instruments, whereas Nissan adopted pouch cells, which have been extra generally utilized in client electronics.
These preliminary designs have been about assembling quite a few small cells into a big battery pack, usually involving advanced cooling techniques to handle warmth and efficiency points. These preliminary designs have been about assembling quite a few small cells into a big battery pack, usually involving advanced cooling techniques to handle warmth and efficiency points.
Professor James Marco, an skilled with 20 years of expertise in electrification who’s head of the Vitality Directorate at WMG on the College of Warwick and leads the Battery Techniques Analysis Group, recollects these early designs.
“For those who examine how battery techniques have developed once we began out, they have been designed to be like a Russian doll,” he says. “It was a battery in a field, in a field, in a field. The battery cells have been usually aggregated into modules, after which these modules turned packs. This multi-layered method resulted in important overhead, resulting in low power and volumetric density. This technique was executed primarily for upkeep as we didn’t perceive how you can optimize the battery system at the moment.”
The drawbacks of those early designs have been evident. Some techniques used air cooling, whereas others employed liquid cooling with quite a few seals that usually failed, resulting in leaks. A notable instance was the Chevrolet Bolt, which skilled frequent failures attributable to its cooling system. Tesla, regardless of utilizing liquid cooling, needed to undergo a number of iterations to optimize its association.
By the mid-2010s, the {industry} started to standardize round just a few key design rules with a big shift in battery design when prismatic and pouch cell codecs have been launched. These codecs have been designed to enhance power density and packaging effectivity, which as Marco explains, “is not only about packing in as many cells as doable; it’s about being extra environment friendly with the cells, making them bigger however extra power dense.”
The development of battery design has been much less about singular breakthroughs and extra a few gradual evolution pushed by the supply of supplies, gear, and standardized approaches. Initially, producers experimented with numerous applied sciences earlier than narrowing down to a couple viable options for mass manufacturing. The evolution has been comparatively gradual because of the readiness of suppliers at a number of ranges.
“The battery {industry} has been on an incremental journey because of value, danger, and uncertainty,” says Marco. “OEMs have been slowly evolving their innovation, however now the tempo of change is accelerating.”
Constructing for the plenty
With the worldwide EV market manufacturing greater than 750 GWh of cells in 2023 (up 40% from 2022), driving down value is paramount. Because the battery accounts for round 30% of the whole car value, this key issue has been an influential power in how battery design has modified.
Early typical battery structure took the type of a module-to-pack (MTP) setup, however new battery know-how traits are transferring in direction of a cell-to-pack (CTP) design, in addition to batteries extra intricately built-in into the car’s construction within the type of cell-to-chassis (CTC) or cell-to-body (CTB) designs that optimize area, dealing with, and efficiency.
To attain these new architectures, one of many greatest variations with trendy designs is the lowered variety of modules. Ten years in the past, opening a battery pack would reveal many modules related in sequence or parallel, usually designed underneath 60V for security causes. This design selection was pushed by upkeep and manufacturing issues. Fashionable battery packs, even when a pack makes use of a cell-to-module structure, characteristic fewer however bigger modules and cells.
As such, a lot bigger bodily, cylindrical cells are coming to market which brings the fee down per kilowatt. For prismatic cells, they’re additionally growing in measurement so {that a} battery solely wants roughly 100-200 in a pack, slightly than a a number of thousand.
The search for increased power density continues to drive innovation. New battery applied sciences, akin to BYD’s Blade battery and Tesla’s tabless 4680 cells, are setting new requirements. These standout examples of cell and pack design scale back inner resistance and enhance thermal administration, contributing to higher effectivity and security.
“The Blade’s cell and pack design is simply splendidly easy,” says Marco. “Inside its low-profile pack are slim rectangular modules, mendacity on a easy chilly plate. The vent path, within the occasion of a failure, merely vents downwards, there’s no want for advanced bus bars, there’s no want for advanced routing of gases or ejected materials. That’s the way it manages to get the packing effectivity so excessive.”
The affect from this innovation is that main automotive OEMs are actually starting to have a look at design and manufacture from the opposite path – slightly than taking a element and optimizing that element for a pack, they’re targeted on optimizing the cell itself.
“Nearly all of the big automotive organizations that we converse to are actually actively concerned in cell design,” says Marco. “They’re not particularly wanting on the electrochemistry aspect; they’re wanting on the mechanical construction of the cell, akin to its measurement and form, to extend packing density and enhance effectivity and security.”
Based on Marco, the pattern now’s for producers to not begin from a small cylindrical battery, however slightly combination up from an 18650 or a 217100.
Huge demand for bespoke batteries
Whereas the mass EV market is setting the tempo, the low-to-medium-volume EV market is to not be left in its mud. From the electrical two and three-wheeled automotive market to marine, industrial car, eVTOL, and off-highway, which mixed are bigger than the mainstream automotive market. All these purposes want battery options however for a lot of producers it’s not so simple as selecting one thing off the shelf.
Raeon, a UK firm that has been working for simply over a yr, is aiming to disrupt the established order of bespoke battery options.
“There are at present two ends of the spectrum for battery design and buying,” says Tom Brooks, co-founder and director at Raeon. “Firms can spend 1,000,000 to get precisely what they need, which comes with a really lengthy lead time. Alternatively, they will spend lots much less for one thing that they are going to in the end need to design the entire car round.”
Raeon sits straight in the midst of these two choices, in a position to make modules in low volumes for purchasers which can be on the lookout for fast prototypes.
“We’re completely aimed toward industries which can be simply dipping their toe into electrification in the intervening time and will not be in a position to undertake customary battery know-how attributable to myriad components. The dimensions of that market is large,” says Brooks.
Packaging constraint is among the greatest challenges OEMs face, notably within the two-to-three-wheeled market, that off-the-shelf battery options can’t deal with. Raeon’s skill to tailor battery packs to particular dimensions and efficiency necessities is a game-changer for these industries.
“We recognized a recurring theme inside battery growth that it’s too costly,” says Murray Schofield, co-founder and director at Raeon. “There are various causes for this, however primarily it’s the best way by which they’re constructed. Quite a lot of customized batteries use injection molders with plastic cell carriers, into which all of the cells get populated. The event and the price of this tooling may be very costly and the lead time to create, finesse and fee can also be substantial. These are one of many important sort of drivers when it comes to funding value, for folks to have the ability to pay money for customized batteries. So, we got down to straight sort out that downside.”
As a substitute of utilizing injection molded plastic carriers to carry cells collectively, Raeon makes use of reactive fluids, which the staff describes as a liquid that types the identical construction as injection molded plastic, however the materials flows across the cells and ultimately units stable. The cell chemistry agnostic materials structurally bonds to the cells themselves to offer a powerful composite matrix construction. It additionally acts a thermal insulator and affords fireplace resistant properties.
Raeon claims it’s the solely firm on the planet creating battery packs utilizing this technique – a revolutionary course of that reduces manufacturing complexity and time, permitting Raeon to supply prototypes in as little as 8 to 12 weeks and absolutely licensed customized batteries inside 6 to 12 months. Raeon additionally importantly factors out they’re much cheaper than {industry} customary.
“By making our batteries in a different way, we will deliver value and lead time down by round 10 instances,” says Schofield. “It is a essential assist to these low to medium quantity prospects recover from the hurdle acquiring a customized software optimized battery with out spending tens of millions, or getting an affordable, off the shelf, sq. field of a battery from China that doesn’t match or actually meet their necessities.”
Raeon’s method to buyer onboarding entails detailed consultations to know particular efficiency necessities, for instance attaining a sure kilowatt hours at a sure voltage. Then, utilizing a CAD mannequin that examines the car’s tolerances and dimensions the Raeon staff proposes a number of choices that explores what number of cells will be packaged into the area and what cell chemistry is true for the applying.
“It’s essential for purchasers to get their fingers on one thing to ensure it’s appropriate for his or her software earlier than spending any cash on pre validation or certification,” says Brooks. “As soon as that after they’ve tried it, we’ll then undergo a extra sturdy validation course of, to a completely signed off, UN 38.3 licensed product.”
Raeon’s trendy product lineup consists of the X Form and X Vitality batteries, designed for various purposes from autos to industrial makes use of. Its X Form is targeted on offering no matter form and measurement battery is required for a buyer. The X Form has large applicability designed for autos and marine options the place power density is essential. Its X Vitality product employs a lot bigger cells which have a tendency to make use of LFP chemistry appropriate for a lot greater batteries. Raeon is aiming this product at extra industrial purposes the place massive mining vehicles, boats, forklift vehicles and power storage will go well with its efficiency. Lastly, it’s planning to launch a brand new providing later this yr aimed on the high-performance car market, nonetheless its specification particulars have been undisclosed.
Challenges forward
Regardless of the developments throughout mass produced and bespoke battery market, a number of challenges stay, notably concerning sustainability and recyclability.
“To see a paradigm shift, we have to perceive how you can design cells and engineer downwards slightly than upwards,” Marco emphasizes. “Fashionable battery packs are doubtlessly being designed as sealed models, optimized for first-life purposes with bonding and becoming a member of that may’t be reversed.”
The query of sustainability extends to the life cycle implications of present designs. “In comparison with the outdated battery fashions, regardless that they have been fairly inefficient when it comes to their volumetric power density, one of many advantages they supplied was that they might be repaired and maintained as you can swap a module out,” says Marco. “Are we actually going to get to a state of affairs the place we’ve got to shred an entire battery pack as a result of one or two cells have malfunctioned?”
Trying forward, Marco sees potential in superior chemistries like solid-state or sodium-ion. “Undoubtedly, the potential power density, energy density, and security alternatives related to solid-state or sodium-ion are very enticing,” he concludes. “However whereas very promising on the know-how stage, we haven’t but labored out how you can manufacture them in quantity.”
The evolution of EV battery design has been marked by important developments and challenges. Because the {industry} continues to innovate, the main focus will possible stay on bettering power density, effectivity, and sustainability whereas navigating the complexities of recent cell chemistries and manufacturing methods.
Chemical brothers
The Subsequent Cell venture, spearheaded by the UK’s Faraday Establishment, focuses on advancing the event of next-generation batteries to fulfill future power calls for. The venture in collaboration with battery producer and Tata Group’s international battery enterprise, Agratas, goals to reinforce the efficiency, lifespan, and security of lithium-ion batteries whereas lowering their prices and environmental affect. By investigating new supplies and progressive cell designs, key areas of analysis embody the exploration of solid-state batteries, which promise increased power densities and improved security profiles in comparison with conventional liquid electrolyte techniques. Moreover, the venture is inspecting different chemistries, akin to sodium-ion and lithium-sulphur batteries, which may provide extra sustainable and cost-effective options.
Efficiency enhancer
Israel-based battery innovator, Addionics, has developed an progressive method to bettering battery efficiency and effectivity by redesigning the interior construction of battery electrodes – a important element in enhancing total battery capabilities. Conventional batteries use dense, planar electrodes that restrict ion circulation, resulting in points with power density, cost/discharge charges, and thermal administration. Addionics goals to sort out these limitations by creating three-dimensional electrode buildings that considerably enhance ion circulation and floor space.
This novel 3D electrode design permits sooner charging and discharging charges, increased power density, and improved thermal stability. By optimizing the structure of the battery electrodes, Addionics claims it may well improve the efficiency of varied battery chemistries, together with lithium-ion, solid-state, and next-generation batteries akin to lithium-sulfur and silicon anode-based batteries.
The corporate’s proprietary manufacturing course of is appropriate with current battery manufacturing traces, making it simpler for producers to undertake and combine Addionics’ know-how with out substantial infrastructure modifications. This adaptability helps speed up the trail to commercialization and broad market adoption.
