Specialists from Alexander Battery Technologies share their perspectives on the challenges, common oversights and practical considerations that can make the transition easier.
Define the requirements before committing to a design
Before getting too far into designing the battery pack, the first thing is to define the requirements. This involves a whole host of issues from looking at voltage, energy, peak and continuous current to duty cycle, the environment the battery will operate in, how it’ll be charged, how it’ll communicate with the equipment, the space it needs to fit into and how long it’s expected to last.
Although this sounds like basic due diligence before any work starts, changing those requirements once the project has started can cause significant delays because so many other decisions have already been made around them. The same applies to regulatory obligations and the markets where the product is going to be sold.
These are not things that can always be dealt with at the end, because they can affect the design of the battery, including its mechanical construction, serviceability and battery management system (BMS) and this is where OEMs can sometimes get caught out. They might already have a few working prototypes and know that the battery powers the product, but that doesn’t mean the pack is suitable for manufacturing at scale or meeting regulatory requirements. Before going too far into computer-aided design (CAD), cells or even a quotation, there needs to be an understanding of what the battery is going to do, where it’s going to go and what it needs to be certified against.
Alexander Battery Technologies production floor
Design for repeatable manufacture, not just a working prototype
There’s a big difference between design for manufacture and design for assembly. You can design every individual component so that it’s easy to manufacture, but when you bring all those parts together, the battery can still be a nightmare to build.
“A prototype that works is not necessarily a product that can be built repeatedly,” explains Owen McNally, Principal Design Engineer at Alexander Battery Technologies.
You can have two nuts and bolts that look absolutely fine when you are looking at the design on a CAD screen because everything appears much bigger, but once you have the physical parts in your hand, you can find there just isn’t enough room to access them easily.
When making one or two packs, somebody might be able to find a workaround. When it comes to making hundreds or thousands, that workaround becomes part of the production process and starts to affect build time and cost, consistency and potentially safety. That’s why design for manufacture and design for assembly need to be part of the new product introduction process, rather than engineers being called back to the line later to do that work retrospectively.
Plan manufacturing and validation alongside development
Product validation and manufacturing process validation need to be considered together, with responsibilities agreed between the OEM and manufacturing partner. This includes establishing the critical-to-quality elements, control plans, acceptance criteria and sample sizes, then using pilot builds to validate manufacturing processes before production ramps up. Process Failure Mode and Effects Analysis (PFMEA) is part of that process too, especially because many of the steps involved in building a battery are similar regardless of battery design. Problems encountered on previous projects can be considered when reviewing a new design. If a particular issue has occurred before, the question is whether the new design works around it, reduces the risk or eliminates it altogether.
One of the biggest mistakes is treating mass production as something that starts after the battery has been designed. Certification, manufacturing and supply chain validation need to influence the design from the very beginning.
Consider how and when the battery will be tested
With a small-scale sample, it can be difficult to determine the true upper and lower performance limits and whether the performance observed across tens of parts will translate to thousands or hundreds of thousands, or whether too many will fall outside those limits.
There’s also the question of where in the manufacturing process the testing should take place. If a printed circuit board (PCB) can be tested before it has been built into the plastics and everything else that makes up the finished battery, it’s much cheaper to discard it at that point than after the additional components and labour have gone into the pack, only to test it at the end of the line and find that it fails.
The same applies to calibration and test fixturing where the manufacturer needs to understand at what point testing and calibration can be carried out and what equipment is needed. Where possible, common test fixtures can make testing easier and less expensive, although some products will require bespoke solutions. Discussing these requirements early can help determine the most efficient approach and influence the battery design where necessary.
The supply chain that works for 100 units may not work for 10,000
A component being available at low volume doesn’t necessarily mean it will be available at production volume. A supplier who can easily produce a few hundred parts could struggle to support tens of thousands without additional tooling, machinery or investment.
The Purchasing team should be involved early on to identify potential issues, understand supplier capacity and lead times, and consider alternative sources where needed. It’s much easier to change a component or supplier before the design is agreed upon than during the production ramp-up, so suppliers need to be asked about target volumes.
Battery cells and battery management systems are particularly important because prototypes can be built quickly using readily available components to prove that the product works, only to find later that the same cell isn’t available from a reliable source or that the BMS lacks the communication required by the finished product. This can mean going back into the design and changing something that had already seemed to be settled.
Forecast confidence becomes more important as volumes increase because suppliers need visibility to plan raw materials and capacity. If a forecast is for 50,000 units but actual demand turns out to be 10,000, a supplier may have invested in materials or capacity that are no longer needed; conversely, an increase from 50,000 to 100,000 could create the opposite problem if there’s not enough capacity to support it.
“Customers don’t need to have everything completely figured out from day one, but the earlier they can share where they believe the programme is heading, the more opportunity there is for us to prepare for the ramp-up rather than react to it,” explains Calvin Fahey, Purchasing Manager at Alexander Battery Technologies.
Strong supplier relationships become increasingly valuable as a project moves into full-volume manufacture. Where there is trust, good communication, and visibility into the longer-term opportunity, suppliers can also be in a better position to consider areas such as holding stock or managing minimum order quantities. Lead times and availability can also directly affect cost. Components that can be sourced quickly in small quantities might have much longer lead times at volume, and if parts then must be air-freighted or sourced rapidly to keep production moving, the additional cost can start to erode product margin.
Scaling production takes more than a manufacturing plan
As volumes increase, one of the biggest challenges is ensuring the entire business is ready, not just the production line. Engineering, purchasing, quality, production, logistics and supply chain all need to work towards the same production plan, and on both the customer and supplier sides there needs to be an understanding of how each other’s activities fit into that plan.
There are a lot of moving parts and often a mismatch between what the customer wants, what the manufacturer wants and what can be delivered, so managing expectations and keeping oversight of the different teams becomes an important part of the project. There will also be risks or areas of uncertainty that remain open as the project progresses, but the important thing is to understand the potential impact, what can be done to reduce the uncertainty and what mitigation is in place if the project continues with that risk still open.
This can be particularly difficult for smaller or start-up businesses that are in a rush to get into production and start generating revenue. They may understand what needs to be done, but under time pressure, processes can be bypassed and things put off on the grounds that they can be fixed later, when the danger is that the work never gets done.
“The sooner you identify and fix a problem, the cheaper it is,” says Chris Muteham, Senior Project Manager at Alexander Battery Technologies.
Change is inevitable in any project, but it needs to be controlled. Changes should be documented and approved, with drawings, specifications and revisions updated so that everyone is working from the latest information. Without a clear process, changes can cause confusion, delays and unnecessary costs, particularly when multiple teams and suppliers are involved.
It’s also important to consider everything needed to deliver the finished product, not just the battery pack itself. Packaging, labelling, documentation and user manuals, including any translation requirements, all need to be accounted for in the project plan. Overlooking these details until late in development can create further costs and delays.
For OEMs moving from small-batch production to volume manufacturing, this can sometimes mean taking a couple of steps backwards before moving forwards, particularly if some of this work was bypassed during development. Making sure the drawings, work instructions, supply chain and responsibilities are in place before going too far down the line provides a much stronger foundation for scaling production.
Ultimately, the transition from prototype to volume manufacture is about much more than producing larger quantities of the same battery pack. It requires engineering, purchasing, quality and production teams to consider how the product will be built, tested, supplied and managed at scale.
The earlier these considerations are brought into the development process, the greater the opportunity to identify potential problems, make informed decisions and avoid costly changes later. For OEMs, involving their manufacturing partner early can help ensure that a battery pack is not only fit for its intended application, but ready for reliable, repeatable production.
Learn more https://www.alexandertechnologies.com/
