Armasuisse radio batteries – industrialization of three radio batteries
- Michael michael.ruhstaller@ceka.ch
- Mar 25
- 4 min read
Updated: Apr 3
From concept to series within one year
At the beginning of 2024, we started the concept phase for three types of radio batteries for military use. The key topics in developing the batteries as a successor solution to an existing battery line were:
Conceptual challenges : Better recyclability, higher mechanical resistance to reduce production costs
Setup : Collaboration in an interdisciplinary team (engineering core team, support from production and equipment construction) with new partners
Technical features of the battery :
Bonding using our own developed bonding robot → Sealing and recyclable
Reduced hand soldering → Use of flexprints for cabling
The main results
At the end of 2023, we were awarded the contract for the MIL battery project in a tender process. The main objective was to produce three battery types starting in 2025 with five-digit annual quantities. The existing battery design was to be fundamentally redesigned.
In the meantime, we are close to starting serial production and have successfully completed the 0-series production of all three batteries.
The batteries meet the stricter requirements for sealing according to protection class IP54 and can be repaired despite the necessary bonding. The battery design has been fundamentally redesigned and is based on the latest manufacturing technologies.
This project was important for us to further expand our expertise in the field of application-specific batteries. We also appreciate the great opportunity to have found a strong partner in Armasuisse.
Project process
Concept development
During the initial project phase, unexpected challenges arose that made the design even more complex than originally envisioned. A change in cell supplier led to larger cell diameter tolerances, necessitating a more compact solution for cell contacting. This limitation necessitated innovative cabling approaches. Specifically, we opted to use flexprints instead of conventional stranded wires to connect the cells and contacts. This solution enabled more efficient use of space and significantly improved ease of assembly.
Concept evaluation from basic development
The specifications stipulated compliance with the test requirements of Military Standard 810. These require various shock and vibration tests, as well as a drop test from over 1.2 meters onto concrete. These requirements could only be met with a fully bonded battery. To ensure these test requirements and the ability to disassemble and repair the batteries, we had to find innovative solutions for cell storage in the plastic housing. We opted for a cell cage that, through the appropriate choice of material, provides the required damping properties and thus relieves the load on the housing.
In order to meet the tight schedule, various sealing concepts were designed and tested, partly in parallel, for all three batteries in order to finalize the concept definition upon completion of the basic development.
Prototype development
During the initial development phase, which lasted approximately three months, all the foundations for the start of the detailed design were laid. A key part of this second phase is the detailed design of the plastic components. We had to continually focus on the compact external dimensions of the batteries, which required minimizing wall thicknesses and targeted reinforcement with suitable ribbing. Before tooling was purchased, all battery properties were tested, where possible, using prototypes and evaluated/approved by the customer.
First prototypes of the cell pack with flexprint cabling
Tool procurement as an important discipline
Despite numerous prototype tests, many mechanical requirements can only be assessed with the final series materials and corresponding components from the series tools. This means that various risks must be carried forward into the investment-intensive procurement phase. We countered these risks by specifically preparing the tool design for potential optimization loops. For example, using tool inserts, partial reinforcement ribs could be subsequently incorporated into the tool at a relatively low cost, allowing the design to be iteratively optimized even after the tool was built.
A complex mix of manufacturing technologies
As trivial as the external shape of the batteries may seem, the mix of different manufacturing technologies we chose for an efficient and performance-optimized design is just as complex. The following is an overview:
Plastic housings and cell holders made of plastic injection molding
Pressed brass contacts directly riveted to flex PCB (flexprint)
Wiring of the battery contacts via flex PCB including integrated resistors
Contact sheet fastening by hot caulking
Spot-welded battery cell sheets (semi-automated)
Sealing the battery covers
Laser-marked nameplates
Series production
Bonding and welding are carried out using specially developed bonding and welding robots. This automation enables the highest precision, consistent quality, and efficient production.
The final critical step in production is the electrical functional testing of each individual battery (charge/discharge test) before the type plate is applied and the batteries are packaged. All batteries are then sent directly to the end user without further testing.
The next steps
By the end of March 2025, we will complete the construction of production lines for three radio batteries. Serial production is scheduled to begin immediately thereafter.
Key learnings and technologies
Despite the tight timeframe, we were able to achieve the project goals on schedule and apply our experience in device development to this battery application. We benefited from the know-how gained from existing battery projects, as well as the strong commitment of the project team and the support of our partners.
The project implementation for the series production of the three batteries described represents an important milestone for us. We are proud to have gained a valuable partner in Armasuisse and look forward to starting production in Q2 2025.
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