The previous decade, the electrical automobile {industry} has witnessed developments in battery pack design influenced by modern design traits. We discover the rising traits shaping the way forward for EV batteries for each mass-market and area of interest automobile purposes.
The not-so-humble battery is approaching 225 years outdated. Over its lifetime, its architectures have come a really good distance from its authentic uncomplicated design. From Alessandro Volta’s rudimentary breakthrough in 1801, which noticed the world’s first battery include 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 present, the worldwide electrical automobile 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 tip of this decade.Regardless of these early restricted capability batteries, evolving design has opened the door for industry-changing applied sciences, significantly 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 outstanding fashions made a big effect: 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. For 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, typically involving complicated cooling methods to handle warmth and efficiency points. These preliminary designs have been about assembling quite a few small cells into a big battery pack, typically involving complicated cooling methods 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 Methods Analysis Group, remembers these early designs.
“In the event you examine how battery methods have advanced after 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 sometimes aggregated into modules, after which these modules grew to become packs. This multi-layered method resulted in vital overhead, resulting in low power and volumetric density. This technique was achieved primarily for upkeep as we didn’t perceive the way to optimize the battery system at the moment.”
The drawbacks of those early designs have been evident. Some methods 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 resulting from 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 a number of 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 attainable; 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, tools, and standardized approaches. Initially, producers experimented with numerous applied sciences earlier than narrowing down to some viable options for mass manufacturing. The evolution has been comparatively sluggish as a result of 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 lots
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 automobile 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 expertise traits are transferring in the direction of a cell-to-pack (CTP) design, in addition to batteries extra intricately built-in into the automobile’s construction within the type of cell-to-chassis (CTC) or cell-to-body (CTB) designs that optimize house, dealing with, and efficiency.
To attain these new architectures, one of many largest variations with trendy designs is the diminished variety of modules. Ten years in the past, opening a battery pack would reveal many modules linked in collection or parallel, sometimes designed beneath 60V for security causes. This design selection was pushed by upkeep and manufacturing concerns. Trendy battery packs, even when a pack makes use of a cell-to-module structure, function fewer however bigger modules and cells.
As such, a lot bigger bodily, cylindrical cells are coming to market which brings the associated fee down per kilowatt. For prismatic cells, they’re additionally rising in measurement so {that a} battery solely wants roughly 100-200 in a pack, fairly than a a number of thousand.
The search for greater power density continues to drive innovation. New battery applied sciences, resembling BYD’s Blade battery and Tesla’s tabless 4680 cells, are setting new requirements. These standout examples of cell and pack design scale back inside resistance and enhance thermal administration, contributing to better 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 complicated bus bars, there’s no want for complicated 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 at the moment are starting to take a look at design and manufacture from the opposite path – fairly than taking a part and optimizing that part for a pack, they’re centered on optimizing the cell itself.
“The vast majority of the big automotive organizations that we converse to at the moment are 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, resembling its measurement and form, to extend packing density and enhance effectivity and security.”
In accordance with Marco, the development now’s for producers to not begin from a small cylindrical battery, however fairly mixture up from an 18650 or a 217100.
Large 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 automobile, 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 choosing one thing off the shelf.
Raeon, a UK firm that has been working for simply over a 12 months, is aiming to disrupt the established order of bespoke battery options.
“There are presently 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 loads much less for one thing that they are going to in the end must design the entire automobile round.”
Raeon sits instantly in the course of these two choices, in a position to make modules in low volumes for purchasers which might be in search of fast prototypes.
“We’re completely geared toward industries which might be simply dipping their toe into electrification in the meanwhile and usually are not in a position to undertake customary battery expertise resulting from myriad components. The dimensions of that market is large,” says Brooks.
Packaging constraint is likely one of the largest challenges OEMs face, significantly within the two-to-three-wheeled market, that off-the-shelf battery options can not handle. Raeon’s potential 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 a lot of causes for this, however primarily it’s the way in which during which they’re constructed. Lots 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 essential type of drivers by way of funding value, for individuals to have the ability to pay money for customized batteries. So, we got down to instantly sort out that downside.”
As an alternative of utilizing injection molded plastic carriers to carry cells collectively, Raeon makes use of reactive fluids, which the crew describes as a liquid that kinds the identical construction as injection molded plastic, however the materials flows across the cells and finally units stable. The cell chemistry agnostic materials structurally bonds to the cells themselves to offer a robust composite matrix construction. It additionally acts a thermal insulator and affords hearth resistant properties.
Raeon claims it’s the solely firm on this planet creating battery packs utilizing this technique – a revolutionary course of that reduces manufacturing complexity and time, permitting Raeon to provide 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 another way, we will deliver value and lead time down by round 10 instances,” says Schofield. “This can be a essential assist to these low to medium quantity clients recover from the hurdle acquiring a customized utility optimized battery with out spending thousands and thousands, or getting an inexpensive, 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 grasp particular efficiency necessities, for instance reaching a sure kilowatt hours at a sure voltage. Then, utilizing a CAD mannequin that examines the automobile’s tolerances and dimensions the Raeon crew proposes a number of choices that explores what number of cells could be packaged into the house and what cell chemistry is true for the applying.
“It’s essential for purchasers to get their palms on one thing to verify it’s appropriate for his or her utility earlier than spending any cash on pre validation or certification,” says Brooks. “As soon as that when they’ve tried it, we’ll then undergo a extra strong validation course of, to a totally signed off, UN 38.3 licensed product.”
Raeon’s trendy product lineup contains the X Form and X Vitality batteries, designed for numerous purposes from autos to industrial makes use of. Its X Form is concentrated on offering no matter form and measurement battery is required for a buyer. The X Form has huge 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 giant mining vans, boats, forklift vans and power storage will swimsuit its efficiency. Lastly, it’s planning to launch a brand new providing later this 12 months aimed on the high-performance automobile market, nevertheless its specification particulars have been undisclosed.
Challenges forward
Regardless of the developments throughout mass produced and bespoke battery market, a number of challenges stay, significantly relating to sustainability and recyclability.
“To see a paradigm shift, we have to perceive the way to design cells and engineer downwards fairly than upwards,” Marco emphasizes. “Trendy 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, although they have been fairly inefficient by way of 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 to shred a whole 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 engaging,” he concludes. “However whereas very promising on the expertise stage, we haven’t but labored out the way to manufacture them in quantity.”
The evolution of EV battery design has been marked by vital developments and challenges. Because the {industry} continues to innovate, the main target will seemingly 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 world battery enterprise, Agratas, goals to boost the efficiency, lifespan, and security of lithium-ion batteries whereas decreasing their prices and environmental impression. By investigating new supplies and modern cell designs, key areas of analysis embody the exploration of solid-state batteries, which promise greater power densities and improved security profiles in comparison with conventional liquid electrolyte methods. Moreover, the venture is inspecting different chemistries, resembling sodium-ion and lithium-sulphur batteries, which might provide extra sustainable and cost-effective options.
Efficiency enhancer
Israel-based battery innovator, Addionics, has developed an modern method to bettering battery efficiency and effectivity by redesigning the inner construction of battery electrodes – a important part in enhancing total battery capabilities. Conventional batteries use dense, planar electrodes that restrict ion movement, resulting in points with power density, cost/discharge charges, and thermal administration. Addionics goals to sort out these limitations by creating three-dimensional electrode constructions that considerably enhance ion movement and floor space.
This novel 3D electrode design allows quicker charging and discharging charges, greater power density, and improved thermal stability. By optimizing the structure of the battery electrodes, Addionics claims it will possibly improve the efficiency of varied battery chemistries, together with lithium-ion, solid-state, and next-generation batteries resembling lithium-sulfur and silicon anode-based batteries.
The corporate’s proprietary manufacturing course of is suitable with present battery manufacturing traces, making it simpler for producers to undertake and combine Addionics’ expertise with out substantial infrastructure modifications. This adaptability helps speed up the trail to commercialization and broad market adoption.
