The previous decade, the electrical automobile {industry} has witnessed developments in battery pack design influenced by progressive design tendencies. We discover the rising tendencies shaping the way forward for EV batteries for each mass-market and area of interest automobile functions.
The not-so-humble battery is approaching 225 years previous. Over its lifetime, its architectures have come a really great distance from its authentic 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 component 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 automobile battery market is predicted to hit US$85.35bn in 2024 and is anticipated to achieve 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 phases, two distinguished fashions made a big effect: the Nissan LEAF and the Tesla Roadster, every using distinct battery applied sciences. These early designs had 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 had been extra generally utilized in client electronics.
These preliminary designs had been about assembling quite a few small cells into a big battery pack, usually involving complicated cooling programs to handle warmth and efficiency points. These preliminary designs had been about assembling quite a few small cells into a big battery pack, usually involving complicated cooling programs to handle warmth and efficiency points.
Professor James Marco, an knowledgeable with 20 years of expertise in electrification who’s head of the Power Directorate at WMG on the College of Warwick and leads the Battery Techniques Analysis Group, remembers these early designs.
“Should you evaluate how battery programs have advanced once we began out, they had 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 had been usually aggregated into modules, after which these modules grew to become packs. This multi-layered strategy resulted in vital overhead, resulting in low power and volumetric density. This technique was completed primarily for upkeep as we didn’t perceive optimize the battery system at the moment.”
The drawbacks of those early designs had been evident. Some programs used air cooling, whereas others employed liquid cooling with quite a few seals that always 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 major shift in battery design when prismatic and pouch cell codecs had been launched. These codecs had been designed to enhance power density and packaging effectivity, which as Marco explains, “isn’t just 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 couple of gradual evolution pushed by the supply of supplies, gear, and standardized approaches. Initially, producers experimented with varied 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 price, 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 price is paramount. Because the battery accounts for round 30% of the entire automobile price, this key issue has been an influential pressure in how battery design has modified.
Early typical battery structure took the type of a module-to-pack (MTP) setup, however new battery expertise tendencies are shifting in 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 area, dealing with, and efficiency.
To realize these new architectures, one of many greatest variations with trendy designs is the decreased variety of modules. Ten years in the past, opening a battery pack would reveal many modules linked in collection or parallel, usually designed beneath 60V for security causes. This design selection was pushed by upkeep and manufacturing issues. Trendy 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 associated fee down per kilowatt. For prismatic cells, they’re additionally growing in dimension so {that a} battery solely wants roughly 100-200 in a pack, fairly than a a number of thousand.
The search for larger power density continues to drive innovation. New battery applied sciences, similar to BYD’s Blade battery and Tesla’s tabless 4680 cells, are setting new requirements. These standout examples of cell and pack design cut back inside 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 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 have a look at design and manufacture from the opposite path – fairly than taking a element and optimizing that element for a pack, they’re targeted 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 facet; they’re wanting on the mechanical construction of the cell, similar to its dimension and form, to extend packing density and enhance effectivity and security.”
Based on Marco, the development now could be for producers to not begin from a small cylindrical battery, however fairly combination up from an 18650 or a 217100.
Massive 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 functions 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 the moment two ends of the spectrum for battery design and buying,” says Tom Brooks, co-founder and director at Raeon. “Corporations can spend 1,000,000 to get precisely what they need, which comes with a really lengthy lead time. Alternatively, they will spend so much much less for one thing that they are going to in the end should design the entire automobile round.”
Raeon sits immediately in the course of these two choices, capable of make modules in low volumes for purchasers which can be searching for fast prototypes.
“We’re completely aimed toward industries which can be simply dipping their toe into electrification for the time being and are usually not capable of undertake commonplace battery expertise resulting from myriad components. The scale of that market is large,” says Brooks.
Packaging constraint is likely one of 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 means 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 lots of causes for this, however primarily it’s the way in which by which they’re constructed. Numerous 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 could be very costly and the lead time to create, finesse and fee can also be substantial. These are one of many important type of drivers when it comes to funding price, for individuals to have the ability to pay money for customized batteries. So, we got down to immediately deal with that downside.”
As a substitute of utilizing injection molded plastic carriers to carry cells collectively, Raeon makes use of reactive fluids, which the crew describes as a liquid that varieties 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 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 supply prototypes in as little as 8 to 12 weeks and totally licensed customized batteries inside 6 to 12 months. Raeon additionally importantly factors out they’re much cheaper than {industry} commonplace.
“By making our batteries otherwise, we are able to deliver price and lead time down by round 10 occasions,” says Schofield. “This can be a essential assist to these low to medium quantity clients 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 strategy to buyer onboarding entails detailed consultations to grasp particular efficiency necessities, for instance attaining 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 might be packaged into the area and what cell chemistry is correct 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 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 fashionable product lineup consists of the X Form and X Power batteries, designed for numerous functions from automobiles to industrial makes use of. Its X Form is concentrated on offering no matter form and dimension battery is required for a buyer. The X Form has vast applicability designed for automobiles and marine options the place power density is essential. Its X Power 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 functions 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 automobile market, nevertheless its specification particulars had 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 design cells and engineer downwards fairly than upwards,” Marco emphasizes. “Trendy battery packs are doubtlessly being designed as sealed models, optimized for first-life functions 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 previous battery fashions, although they had 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 possibly can swap a module out,” says Marco. “Are we actually going to get to a situation the place we’ve got to shred a whole battery pack as a result of one or two cells have malfunctioned?”
Wanting 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 expertise degree, we haven’t but labored out 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 doubtless stay on bettering power density, effectivity, and sustainability whereas navigating the complexities of recent cell chemistries and manufacturing strategies.
Chemical brothers
The Subsequent Cell undertaking, spearheaded by the UK’s Faraday Establishment, focuses on advancing the event of next-generation batteries to fulfill future power calls for. The undertaking 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 lowering their prices and environmental influence. By investigating new supplies and progressive cell designs, key areas of analysis embody the exploration of solid-state batteries, which promise larger power densities and improved security profiles in comparison with conventional liquid electrolyte programs. Moreover, the undertaking is inspecting different chemistries, similar to 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 progressive strategy to bettering battery efficiency and effectivity by redesigning the interior construction of battery electrodes – a vital element in enhancing general 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 deal with 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, larger power density, and improved thermal stability. By optimizing the structure of the battery electrodes, Addionics claims it will probably improve the efficiency of assorted battery chemistries, together with lithium-ion, solid-state, and next-generation batteries similar to lithium-sulfur and silicon anode-based batteries.
The corporate’s proprietary manufacturing course of is suitable with current 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.
