| Abstract | Kako je kupnja električnih automobila posljednjih godina u porastu, sve više pažnje usmjerava
se na poboljšanje njihovih performansi. S obzirom da su performanse vozila kao što su energija,
snaga i velika brzina punjenja moguće samo ukoliko je hlađenje baterije dobro osmišljeno, u
ovom radu analiziran je rashladni sustav baterije. Kod vozila visokih performansi baterija se
hladi s kapljevinom u direktnom ili indirektnom kontaktu, a u ovom radu analiziran je sustav
indirektnog sustava hlađenja. Usmjerila se pažnja na kontaktni otpor između baterije i rashladne
ploče, odnosno ljepilo koje ih drži zajedno. U radu se ispitalo kako prekrivenost ljepila utječe
na prijenos topline – točnije koliko je aksijalni prijenos topline oslabljen ukoliko se ljepilo ne
nanese u dovoljnoj količini na površinu baterije. Ispitivanje je napravljeno za 4 vrste ljepila od
kojih su dva strukturna, a dva su termalna, te su njihovi rezultati međusobno uspoređeni.
Ispitivanje se provodilo na način da se između dviju aluminijskih pločica nanijelo ljepilo u
promjerima od 20 i 80 mm, u debljini od 0,5 mm koja se osigurala postavljanjem mjernih listića
između pločica. Svako ljepilo ispitano je kroz 2 ispitna modela (pokrivenost od 20 i 80 mm) za
koja su korištena po 3 ispitna uzorka. Prijenos topline mjeren je na način da su uzorci stavljeni
na grijač konstante temperature od 60°C mjereći vrijeme u kojem svaki od njih dostigne
ustaljenu temperaturu. Grijač je napravljen pomoću ARDUINO sustava i postavljena mu je PID
regulacija. Prije samog ispitivanja, napravljena je simulacija u Simulinku kako bi se dobili
okvirni rezultati te je opisan matematički model koji je korišten za modeliranje.
Za vrijeme ispitivanja mjerile su se temperatura grijača i gornje pločice te PWM signal u
razmacima od 300 ms, a vrijednosti su im automatski zapisane u Excel tablicu. Obradom tih
podataka dobili su se rezultati koji prikazuju da je prijenos topline svih ljepila značajno bolji
kod uzoraka od 80 mm. Gornja pločica se kod njih zagrijavala puno brže te na više temperature
nego kod uzoraka od 20 mm. Kod uzoraka od 20 mm gornja pločica strukturnih ljepila se
zagrijala na temperaturu od 52°C, dok se kod termalnih ljepila u istom vremenu postigla
temperatura od 55°C. Kod uzoraka od 80 mm strukturna ljepila postigla su temperaturu od
56°C, a termalna 58°C. Tromost ljepila opisana je vremenskom konstantom τ koja daje vrijeme
u kojem se temperatura termopara povisi za 68,3%. Za termalna ljepila prosječan τ kod uzoraka
od 80 mm iznosi 1.34 min, a kod strukturnih je njegova vrijednost 2.00 min. Kod uzoraka od
20 mm vrijednost τ strukturnih ljepila povećala se u prosjeku za 35%, a kod termalnih za 47.5%. |
| Abstract (english) | As the purchase of electric cars has been on the rise in recent years, more and more attention is
focused on improving their performance. Given that the performance of the vehicle, such as
energy, power, and high charging speed, is possible only if the cooling of the battery is well
thought out, in this paper the cooling system of the battery is analyzed. In high-performance
vehicles, the battery is cooled with liquid in direct or indirect contact, and this paper analyzes
the system of the indirect cooling system. Attention was focused on the contact resistance
between the battery and the cooling plate, the glue that holds them together. The paper examined
how the coverage of the adhesive affects the heat transfer - more precisely, how much the axial
heat transfer is weakened if the adhesive is not applied in sufficient quantity to the surface of
the battery. The test was done for 4 types of glue, two structural and two
thermal, and their results were compared with each other. The test was carried out in such a way
that glue was applied between two aluminum tiles in diameters of 20 and 80 mm, with a thickness
of 0.5 mm, which was ensured by placing measuring sheets between the tiles. Each adhesive
was tested through 2 test models (coverage of 20 and 80 mm), for which 3 test samples were
used. Heat transfer was measured in such a way that the samples were placed on a heater with
a constant temperature of 60°C, measuring the time in which each of them reached the
established temperature. The heater is made using the ARDUINO system and has PID
control. Before the test, a simulation was made in Simulink to obtain preliminary
results, and the mathematical model used for modeling was described.
During the test, the temperature of the heater and the upper plate, and the PWM signal were
measured at intervals of 300 ms, and their values were automatically recorded in an Excel table.
By processing these data, results have shown that the heat transfer of all adhesives
is significantly better with 80 mm samples. In the case of 20 mm samples, the upper plate of
structural adhesives heated up to a temperature of 52°C, while in the case of thermal adhesives,
a temperature of 55°C was reached at the same time. In the case of 80 mm samples, structural
adhesives reached a temperature of 56°C, and thermal 58°C. The inertia of the glue is described
by the time constant τ which gives the time in which the temperature of the thermocouple rises
by 68.3%. For thermal adhesives, the average τ for 80 mm samples is 1.34 min, and for
structural adhesives, its value is 2.00 min. For 20 mm samples, the τ value of structural
adhesives increased by 35% on average, and for thermal adhesives 47.5%. |
| Study programme | Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering, Mechatronics and Robotics, Autonomous Systems
Course: Process and Energy Engineering
Study programme type: university
Study level: graduate
Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva) |
