## 1 Introduction
### Contribution and Paper Organization  
In light of previous research that demonstrated various wireless data links [24; 25] utilizing platforms external situated on different battery's architecture level such as cells, packs, modules and batteries [5; 6; 20; 25; 26; 27; 28], this study will investigate the possibility of establishing a viable data link by transmitting from within an 18650-cell shell. Additionally, since examples of RF transceivers being used within a restrictive metal enclosure have been reported in both the communication [29; 30] and radio location [31] domains, this study's scenario proposes a challenging but realistic perspective. In this experiment, the selected frequencies of 868 MHz and 2.4 GHz will be tested on a range of 1 m up to 10 m using two types of radiative structures inside an 18650-cell shell: sub miniature version A (SMA) connector and a wire loop. Furthermore, the test will be conducted at close range of 0.1 m-0.2 m of a reflective surface emulating a mobile platform's battery environment, with the radiative cell oriented vertically and then horizontally in relation to the surface. The tri-dimensional (3D) radiation pattern from insertion of antenna inside the cell's shell will be visualized using a MATLAB electromagnetic simulation, whereas the experimental test results will be validated using RF modelling.  
Towards the development of a network communication demonstrator based on smart cells, preliminary studies such as this one are essential, where simplifications and system-specific lab tests required lead to more advanced technological readiness levels (TRL) [32; 33]. In Figure 2, we highlight briefly the particular case of a smart cylindrical Li-ion cell to be developed in the next TLR stage once we have proven that wireless communication can be successfully implemented inside a metal enclosed shell. The work's metrics such as transmission range, frequency, data rate, payload derived from the received signal strength indicator (RSSI), bit error rate (BER) and packet error rate (PER), provides possible  
Figure 1: Battery monitoring system (BMS) research objectives.  
fundamental references for studies addressing similar structural functionality. In contrast, the constructed legacy will support and reinforce future laborious development efforts, such as PCB design, electrolyte-resisting coating, encapsulation inside a cell, and testing within a compact network for accessibility and reliability.  
The work presented in this article is organised in four main sections. The introduction explains the study's background and motivation. The second section presents the methodology, instruments, systems interconnectivity and characteristics. In this methodology section, the RF experimental ranging setup is accompanied by a MATLAB simulation which provides complementary data regarding the 3D resulted radiative elements and laboratory propagation profile based on a three-ray model. Based on simulations and empirical results, the third section discusses the results and the potential implications of data variation. The final section concludes with a summary of the study's findings and a list of possible benefits.