At Epec, we are in a unique position of having the capabilities to produce domestically at our Colorado tech center, our Massachusetts assembly facility, or your partner factories in Asia. This allows us both flexibility and control on prototype development, regulatory builds, pilot ruins, and production quantities.
Being an approved battery pack assembler for some of the top tier manufacturers such as Panasonic, A123, and Varta, the approval process is streamlined to be able to begin designs and prototypes without delay. We have designed various handheld instrumentation and medical devices for these suppliers to understand our emphasis on safety.
There are challenges with lithium battery pack designs to ensure the safety and shipping requirements are met, the goal being to pass regulatory testing at the first submission. Our track record for this is second to none. We take great pride in working closely with the customer at the development stage to understand the scope of the project, chemistry and cell selections, long term goals, and to educate them on potential transportation restrictions to meet a robust design solution they can market and manage.
Batteries Charging Prior to Shipment
When it comes down to specific battery pack lead time to market, there are several things to consider. The first being the chemistry selection, understanding design needs to be developed and approved. Actual prototype builds need to be produced, tested, and approved prior to regulatory or production builds, and with lithium, the UN38.3 transportation certification is required.
Custom Battery Design Timelines
Our design timelines vary depending on the chemistry and complexity of the battery functions, but a general rule of thumb is 3-4 weeks for this step. Once the design has been approved, we produce prototypes to allow the customer to test the battery in their intended device. Producing samples is typically a 4-week process but will vary depending on the cell selection and availability from that manufacturer. The prototype(s) then requires the customer to physically test them for form fit and function. Sometimes this is a fast bench verification process, but it may also require actual field testing that should be considered in the lead times.
Epec can also design and manage any enclosures that may be required. We can also assist in the design to ensure all battery protocol and transportation requirements are met. The enclosure design step should be considered when factoring lead times as it requires in-depth reviews with Epec and customer design team, frequently on line reviews and data changes before the final version is met. The design step is approximately another 4 week process depending on the complexity, and as stated, requires involvement and approvals from the customer before moving to tooling.
Tooling & Battery Pack Enclosures
Tooling an enclosure is a lengthy mold process. A common method to confirm enclosure designs and provide low quantities for prototyping is done using FDM (Fused Deposition Modeling). FDM is a great option when you need freedom of design with high build accuracy and you require engineering-grade accuracy. FDM parts are durable and ideal for low volume of end use parts (1-10), conceptual models, engineering models, and functional testing prototypes. They are ideal for form fit and function testing because they are able to withstand rigorous testing, won’t shrink, warp, or absorb moisture. Epec has FDM capability and is used in many applications including this prototype step.
The actual tooling of plastic enclosures can also vary in lead times. Design, material intended, and finishes to the part are all factors to be considered. A first article approval step is required once the tooling has been finished. There are really no “averages” when it comes to tooling lead times due to the variables. However, considerations should be taken and accurate timelines can be provided once the design is finalized.
Most battery pack enclosures are designed to be ultrasonically sealed. Epec manages that process as well, typically done laterally with the enclosure tooling, coordinated and confirmed with the first articles produced through the enclosure molds. This step will add a few weeks to the lead time because the welding has to be confirmed on the actual tooled samples prior to the ultrasonic horn and nest being finalized through a surface hardening process.
Battery Regulatory Testing
With the lithium chemistry, the regulatory testing step needs to be performed as the battery is intended to be shipped. If the battery requires an enclosure, the above steps need to be taken prior to submitting to the UN38.3 transportation testing. The design needs to be approved by the customer regardless if it is intended to be supplied within an enclosure or provided as a soft pack.
We are very familiar with UN38.3 transportation requirements, as earlier stated, design to meet all criteria with the goal to pass on first submissions. This step requires an additional sample lot produced and submitted once the design has been approved. Typically 17 samples are required, the test itself takes anywhere from 6-8 weeks depending on the agency backlog at the time of submission. The sample lot may take up to an additional 4 weeks to produce (depending on cell selection and availability), so a total of 8-10 weeks should be factored in on this step.
Other chemistries such as Ni-MH, Ni-Cd, or Alkaline do not require regulatory testing or certification for transportation, and would follow the above outline minus the UN38.3 step.
Conclusion
The best way to determine specific custom battery pack lead times on any chemistry or design is to send us your project. We would be happy to discuss and provide a detailed proposal.
