Summary of "Embedded Systems and Design & Development - Feb 3, 2026 | Morning | VisionAstraa EV Academy"
Session purpose and logistics
- Course focus: fundamentals of electric vehicles (EVs) with emphasis on batteries and battery-pack design as a prerequisite to later embedded-systems, control and protection design.
- Format and schedule:
- Two weeks online: daily morning/afternoon sessions on different topics; recordings shared end of day.
- Followed by two weeks offline, hands-on lab/workshops at VTU Nagari (starting ~Feb 16) and other VTU campuses (Bellagi, Bagawi). Offline accommodation available at some campuses; Bangalore students expected to arrange PG/commute.
- Morning sessions cover basics; afternoons and evenings cover deeper design and practical examples. Hands-on projects and teardown/assembly will be done in offline labs.
- Admin notes: ask questions via messages (high call volume). Recorded sessions will be shared.
High-level course message
- EVs are multidisciplinary: mechanical, electrical, electronics and computer science (embedded systems). Understand vehicle basics before programming or protective-device design.
- Strong industry opportunity: many new OEMs (post‑2019) alongside legacy ICE brands — promising prospects for students.
Battery fundamentals
A battery is an electrochemical device that stores electrical energy as chemical energy and returns it as electrical energy — often described as the “heart” of an EV.
- Two broad classes:
- Primary cells: single-use, non-rechargeable (e.g., remote controls, coin cells).
- Secondary cells: rechargeable; used in EVs (lead‑acid, gel, NiCd, sodium‑ion, lithium chemistries).
Chemistries and key comparative metrics
Lead‑acid / Gel
- Lead‑acid: low energy density (~30–50 Wh/kg), cycle life ~200–350 cycles, nominal cell voltage ≈ 2.0 V.
- Gel: similar to lead‑acid but higher cycle life (~350–500 cycles); slightly longer usable life.
- Advantages: low cost and wide availability.
Lithium‑ion (NMC / general Li‑ion)
- Nominal voltage: ~3.7–3.75 V per cell; full-charge ≈ 4.2 V; cut-off ≈ 3.0 V.
- Energy density: ~200–300 Wh/kg.
- Typical cycle life (class): ~1,200–2,800 cycles (depends on chemistry/conditions) → roughly 4–5 years at 1 cycle/day.
- Good fast‑charging potential; higher cost.
Lithium Iron Phosphate (LiFePO4 / LFP)
- Nominal voltage: ~3.2 V per cell.
- Cycle life: ~750–2,000 cycles (often used for long‑life applications) → often 6+ years.
- Energy density: ~120–200 Wh/kg (lower than NMC) but better thermal stability and safety.
- Often preferred where long life and safety are prioritized.
Sodium‑ion (overview)
- Nominal voltage: ~3.0–3.1 V per cell.
- Energy density: ~100–160 Wh/kg.
- Some claims of very high cycle life (~2,000–5,000).
- Potentially lower cost due to abundant raw materials.
Other comparison factors
- Temperature performance ranges, fast‑charging capability, cost and resource/geopolitical constraints (e.g., lithium supply concentration), and environmental aspects.
Key parameters (fundamentals to record)
- Nominal (platform) voltage per cell (used for pack calculations):
- Li‑ion (NMC): ~3.7–3.75 V
- LFP: ~3.2 V
- Lead‑acid: ~2.0 V
- Sodium‑ion: ~3.0–3.1 V
- Full‑charge voltage per cell (example for NMC/Li‑ion): 4.2 V
- Cut‑off (0% SOC) per cell (example for Li‑ion): ~3.0 V
- Cycle life (number of full charge/discharge cycles)
- Energy density (Wh/kg)
- Temperature operating range and fast‑charge capability
- Capacity units: mAh / Ah (milliamp‑hour vs amp‑hour)
- Energy calculation: Wh = V_nom × Ah
State‑of‑Charge (SOC)
- Voltage‑based SOC mapping example for Li‑ion/NMC (approximate):
- 100% ≈ 4.2 V per cell
- 50% ≈ ~3.6 V per cell
- 0% ≈ ~3.0 V per cell
- Note: voltage‑to‑SOC mapping is an approximation; accurate SOC estimation depends on manufacturer datasheets and more advanced methods (Coulomb counting, impedance, model‑based estimation).
Pack‑design fundamentals — series & parallel wiring
Wiring basics
- Parallel: connect all positives together and all negatives together.
- Voltage remains same as one cell; capacity (Ah) adds.
- Example: three 4.0 V / 2.6 Ah cells in parallel → 4.0 V, 7.8 Ah.
- Series: connect positive of one cell to negative of the next.
- Voltage adds; capacity (Ah) remains that of a single cell.
- Example: three 4.0 V / 2.6 Ah cells in series → 12.0 V, 2.6 Ah.
Design steps / decision flow
- Define required pack nominal voltage and required pack capacity (Ah).
- Choose cell chemistry and cell nominal voltage and capacity (from datasheet).
- Calculate series count (S) = required pack voltage / cell nominal voltage (round to integer).
- Calculate parallel count (P) = required pack capacity / cell capacity (Ah) (round up; choose integer).
- Pack total cells = S × P.
- Compute pack nominal voltage = S × cell nominal voltage.
- Compute pack full‑charge voltage = S × cell full‑charge voltage (e.g., S × 4.2 V for Li‑ion).
- Compute pack cut‑off voltage = S × cell cut‑off voltage (e.g., S × 3.0 V).
- Compute pack energy (Wh) = pack nominal voltage × pack Ah.
- Select charger rated to the pack full‑charge voltage (charger V ≈ pack full‑charge voltage).
- Consider BMS, protective devices, balancing method, temperature limits, and required C‑rate.
- Validate cycle‑life, safety and thermal management requirements for chosen chemistry.
Worked examples
- Convert a 12 V, 20 Ah battery to 36 V, 20 Ah: use 3 × 12 V batteries in series.
- Make 60 V, 20 Ah from 12 V, 20 Ah: need 5 in series.
- Using 18650 cells:
- Dimensions: 18 mm diameter × 65 mm height.
- Example cell spec: 2,600 mAh (2.6 Ah), nominal 3.7 V (some examples used rounded 4.0 V for easier arithmetic).
- 3 cells in series of 4.0 V nominal → 12 V nominal; full charge ≈ 12.6 V (3 × 4.2 V); 50% ≈ 10.8 V (3 × 3.6 V); 0% ≈ 9.0 V (3 × 3.0 V).
Important unit distinctions
- mAh / Ah = capacity.
- Amp (A) = instantaneous current.
- C‑rating relates to charge/discharge rate.
- Watt‑hours (Wh) = V_nom × Ah = energy content.
Additional technical points
- Practical design must consider balancing, BMS, thermal behavior, charging protocol and safety (operating voltage window, temperature).
- Manufacturer datasheets and application‑specific constraints affect usable SOC limits and pack energy.
- Energy density, cost, supply‑chain factors (e.g., lithium sourcing), and charge/discharge performance influence chemistry selection.
What to expect next in the course
- Afternoon/evening sessions: deeper calculations (Ah/Wh/VAR), larger battery‑pack design, protective device design, BMS and safety, and practical assembly/teardown in labs.
- Offline hands‑on sessions will include manufacturing and testing battery packs, full teardown of vehicles, integration and protective circuit design.
Speakers / sources featured
- Nikil G — host / introducer (VisionAstraa EV Academy)
- Punit K — main instructor / mentor (industry practitioner; runs multi‑brand EV service company)
- Vajira — backend / session coordinator
- Aish — moderator support (closed session)
- Audience / students — participated in Q&A
(End of summary.)
Category
Educational
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