Lithium-Ion Battery Technology – Comprehensive Study Notes

Page 1

• Topic introduction: “Lithium-Ion Battery Technology – Is Lithium-Ion Battery Technology Right For You?”
• Presenter: Marlene McCartha, AC & DC Power Technologies.

Page 2 – Applications

• Industrial / stationary uses only (consumer & motive loads excluded).
Applications considered:
– Station Power (switchgear, control power, PV)
– Uninterruptible Power Systems (UPS)
– +24 VDC / –48 VDC Telecom
– Engine-generator start / centrifugal fire pump
– Transit switching & signalling
– Energy storage / load levelling
– Voltage support / flicker control
• Chemistries referenced: NMC, LFP, LTO, NCA.

Page 3 – Key Performance Topics

• Capacity: Watt-hours vs. ampere-hours.
• High energy density; fast recharge; flat discharge curve.
• Predicted float life (shelf life).
• Cycle life vs. float life.
• Temperature tolerance, reliability, safety.

Page 4 – “Spider-Graphs” (qualitative radar charts)

• Figures compare chemistries (LTO, LCO, etc.) across performance traits (energy, power, life, cost, safety…).
• Source: Battcon paper (Jim McDowell) & Battery University.

Page 5 – Spider-Graph Example Discussion

Example metric – Power Density: very high but life & high-temperature operation poor; energy density & safety excellent.

Page 6 – Standards Effort

Reference: Mitsubishi Electric site.
IEEE WG 1679-1 is writing common criteria for performance & safety comparison of lithium chemistries.

Page 7 – Wh vs. Ah (lead-acid context)

Charts show discharge current vs. time vs. end-voltage.

Page 8 – Classical 10-h “nameplate” rating

Formula $\text{Capacity (Ah)} = I \times t$. Example: $10\;h \times 23\;A = 230\;Ah$.

Page 9 – Rate-of-discharge effect

30-min: $30\;\text{min}\times \tfrac{1\,h}{60\,min} \times 144\,A = 72\,Ah$. 10-h: $10\,h \times 23\,A = 230\,Ah$.
Slower discharge ⇒ more delivered energy.

Page 10 – Watts relationship

$P = V \times I$.
Energy (Wh) = $V \times I \times t$.

Page 11 – Watt-hour rating methodology

Lithium vendors quote Wh to highlight energy density. Example: $3.6\,V \times 42\,Ah = 151\,Wh$.

Page 12 – Ragone-type plot

Specific power vs. specific energy.
Li-ion variants occupy high-energy / high-power corners vs. Ni-Cd, Ni-MH, lead, super-caps.

Page 13 – 240 Vdc Generation-plant load profile

Loads: continuous UPS, control loads, trip coils, spring-charge motors, DC lube-oil pump; 8-h profile illustrated.

Page 14 – Raw-material spot prices (USD/lb)

Titanate oxide $25.70$, cobalt oxide $14.52$, lithium carbonate $7.36$, nickel $5.60$, new lead $0.92$, scrap lead $0.75$.
Shows transparency issue of true cost.

Page 15 – Cost comparison 240 Vdc / 50 kW × 8 h (400 kWh) plant UPS

Flooded/VRLA/Ni-Cd solutions $135–384\,k$.
Lithium LFP $288\,k$ (higher CapEx but lower space & maintenance).

Page 16 – Substation 120 Vdc load profile

Worst case: all breakers trip at outage start & again at restoration. 8-h continuous control load in between.

Page 17 – Substation 120 Vdc cost table

Range: VRLA calcium $2.8\,k$ (cheapest) → Lithium Titanate $14\,k$ (highest). SLFP $12.2\,k$.

Page 18 – Data-Center UPS profile

480 Vdc, 15-min discharge, 750 kW. Voltage vs. time graphs show falling V during load.

Page 19 – 15-min 750 kW UPS Comparison (480 V)

Weights, footprints, cost: lithium LFP $214.8\,k$, NMC $205\,k$ at 28 klb; Lead-acid VRLA needs six strings, heavier (29 klb) but cheaper $98\,k$; flooded Ni-Cd is $390\,k$ and 47 klb.

Page 20 – 5-min UPS comparison

Lithium LFP cheapest ($107.4\,k$) & lightest (5.2 klb); LTO highest at $312\,k$. Lead alternatives heavier.

Page 21 – Electrode configuration table

Chemistries vs. construction: LTO (prismatic), LFP / SLFP / NCA / NMC (cylindrical jelly-roll). Implication: thermal control & form factor.

Page 22 – Cylindrical cell benefits

• Good heat dissipation, high-temp management, flexible mechanical design, lower cost (figs 1–4 illustrate jelly roll structure).

Page 23 – Prismatic cell benefits

• Good heat dissipation, flexible shapes, super-fast charging, reduced SEI growth & Li plating at low T.

Page 24 – Electrolyte flashpoints

IFC-2018 Ch-12 & NFPA-1 Ch-52 list FP of popular solvents (e.g., ethylene carbonate, dimethyl-carbonate) ➔ fire-code relevance.

Page 25 – Cycle life curve: Ni-Cd pocket plate

Shows 1 400 cycles ≈ 80 % capacity left, IR rise, self-discharge trends.

Page 26 – Lead-acid grid alloy cycle testing

Lead-selenium best; calcium weakest; 1 600 cycles max at ≈20 % capacity.

Page 27 – Li-ion vs. graphite/LTO cycle life

At 10 C charge & 25 °C, LTO retains >80 % for >10 000 cycles; graphite anode drops earlier. Demonstrates superior cycle life.

Page 28 – Standards matrix

Sizing IEEE 485/1115 (lead/Ni-Cd) – none yet for Li-ion.
Maintenance IEEE 450/1188/1106 vs. IEEE 2030.2.1 for Li-ion BESS.
Fire protection NFPA 52.3.2.7-8 & NFPA 850 Ch-4 for all chemistries.

Page 29 – Operating-temperature comparison

Table of chemistries (cell voltage, Wh/kg, temp range, cycles). Highlights:
– LTO: $2.3\,V$, $60–110\,Wh/kg$, $0–40\,°C$, >10 000 cycles.
– SLFP+NCA: $3.7\,V$, $90–120\,Wh/kg$, −40–50 °C, 7 000 cycles.
– NCA >200 Wh/kg but only 4 300 cycles.

Page 30 – Specific-energy re-tabulation

Same numeric table emphasizes Wh/kg hierarchy: NCA > SLFP > LFP > LTO > lead.

Page 31 – Cycle-life re-tabulation

Same data focusing on cycles: LTO > SLFP > LFP > NCA > Ni-Cd > VRLA > flooded lead.

Page 32 – Storage / self-discharge table

LTO & LFP+NCA shelf life 12–15 yrs, low self-discharge. VRLA Ca only 6 months. Humidity / temp constraints listed.

Page 33 – Limitations (general)

Humidity, storage limits, code-imposed quantity limits, fire clearances, shipping, proprietary BMS, cost, and best value only for short-duration discharges.

Page 34 – Maintenance (IEEE 2030.2.1)

Tasks: vacuum/clean, torque checks, BMS data download, thermal scans, firmware updates. UL 1642.5 requirement for field-replaceable modules.

Page 35 – Safety architecture

Per-cell monitoring (V, T, I); per-string protection, hardened PLC, thermal-runaway alarms at $55\,°C$, disconnect at $65\,°C$, CANbus comms; cell-level disconnect enables N+1 fault tolerance.

Page 36 – Cabinet types

NEMA 1, 3R, 4X; top cabling, hinged doors, seismic/non-seismic.

Page 37 – Natural aging modes

Intercalation side-reactions ↓conductivity. Repetitive cycling gradually reduces beginning-of-life (BOL) capacity.

Page 38 – Premature aging / abuse

Internal overheating ⇒ venting & string removal.
Cell imbalance (over/under-charge) accelerates aging & temperature rise.
Lithium plating from deep discharge + fast recharge or cold-charge.
Dendrite deposition ⇒ internal shorts.

Page 39 – Cabinetized system design

90 in (2 286 mm) typical; multi-string vs. single; DC disconnects. Components: BMS, alarms, comms, hardened electronics, NEMA 1/3R/IP54 enclosures; seismic rated IFC 1206.2.4.

Page 40 – Safety concern matrix & remedies

Over-T, over-V, over-discharge, thermal-runaway (alarms $55\,°C$, terminate $70\,°C$), moisture, rupture, fire propagation, comm failure, BMS failure, charge-control failure – each mitigated by cabinet/system features (disconnects, redundancy, containment, UL 9540A testing, etc.).

Page 41 – Certification landscape

UL 9540/9540A, UL 1973, IEC 61508, IEC 62040-1-3, IEEE P2686, FCC Part 15, FM DS 5-33.

Page 42 – Additional cabinet safety details

UL 1642/1973/9540 cell tests; per-cell OC/OV/OT, impedance measurement, module-level fuse & microcontroller, non-combustible cabinets (IFC 608.4.2), hardened electronics (UL 1998, IEC 61000-6-2), redundant monitoring; cell balancing standard.

Page 43 – Shipping regulations

Each cell/module ships individually; replacement cells carrier-restricted.
UN Classes: Stand-alone Li-ion UN 3480 (P.I. 965), packed w/ equipment UN 3481 (P.I. 966/967).
Spent batteries = Class 9; 3–6 mo to secure air approval; CDL haz-mat driver; UN/DOT 38.3 testing; 49 CFR 173.185 packing.

Page 44 – LiFePO₄ electrochemistry (schematic)

Two-part reaction: $\text{LiFePO}<em>4 \leftrightarrow \text{FePO}</em>4 + \text{Li}^+ + e^-$ (cathode) and $\text{Li}^+ + e^- + C \leftrightarrow \text{Li}C_5$ (anode).
Collecting foils: Al (cathode), Cu (anode).
Charging = left→right. Electrolyte mixture EC/DMC.

Page 45 – LiFePO₄ chemistry (continued)

Same reaction reiterated; EC & DMC solvents defined. Larger per-cell voltage reduces series cell count.

Page 46 – Nominal voltage determination

Flat discharge plateau intersects average line at $3.2\,V_{nom}$ for LiFePO₄.

Page 47 – Gravimetric capacity gain

LiFePO₄ delivers ≈3.5× capacity per kilogram vs. high-rate lead-acid.

Page 48 – End-of-discharge voltage differences

Lead-acid standard $2.0$ or $1.75/1.68\,V$ pc; Li-ion spec different (higher) – impacts usable capacity & sizing.

Page 49 – Charge characteristics & self-balancing

Graphs compare LiFePO₄ vs. lead-acid charging voltage/current vs. SOC. LiFePO₄ tolerates some over-charge and shows cell self-balancing near 90–100 % SOC; 10 % cell imbalance example.

Page 50 – Charger compatibility warning

UPS/charger float & boost voltages adjustable; must align with Li-ion spec for proper sizing & life.

Page 51 – Self-balancing explanation

Cells exhibit slight divergence in reaching 100 % SOC; BMS ensures equilibrium over cycles.

Page 52 – LTO chemistry overview

Reaction: $\text{Li}<em>4\text{Ti}</em>5\text{O}<em>{12} + 6\text{LiCoO}</em>2 \leftrightarrow \text{Li}<em>7\text{Ti}</em>5\text{O}<em>{12} + 6\text{Li}</em>{0.5}\text{CoO}_2$.
Cell potential $2.1\,V$. Patented; Al & Cu collectors; note absence of carbon (improved safety; prevents SEI & plating).

Page 53 – LTO notes continuation

Same reaction; highlights carbon-free anode -> high rate, long life, safer; $2.1\,V$ cells require more in series for given system V.

Page 54 – 2018 IFC chapters affecting lithium

Ch 7–10 (fire/smoke, finish, life safety, egress) & Ch 12 (energy systems, §1206.2 stationary batteries) & Ch 33 (construction fire safety).

Page 55 – Battery-room design checklist

Lead/Ni-Cd vs. Li-ion: Li-ion needs electrical PPE, disconnects, gas detection, signage, fire suppression, 36 in clearances; no spill containment/neutralization required.

Page 56 – Code matrix (IFC 608.1 ≤2018)

Venting, spill control, neutralization, ventilation: required for lead/Ni-Cd; thermal-runaway management required for Li-ion; seismic & smoke detection required for all.

Page 57 – Additional IFC/NFPA lithium restrictions

• Auto-disconnect on over-T
• Install below 75 ft height but >30 ft below grade
• High-hazard classification when MAQ exceeded
• 36 in separation between arrays/equipment unless 1-h rated
• Extra permits & placement rules (§506.4/5, 508.2.3, etc.).

Page 58 – Maximum Allowable Quantities (MAQ)

Overall facility: Li-ion limited to $600\,kWh$ before Group H-2. Lead & Ni-Cd unlimited; flow, sodium also 600 kWh.

Page 59 – MAQ example for 750 kW, 15-min UPS

Energy needed $E = 750\,kW \times 15/60\,h = 187.5\,kWh$.
$600/187.5 ≈ 3.2$ → maximum three such UPS battery systems per building without H-2 classification.

Page 60 – Single-string MAQ

Li-ion limited to $20\,kWh$ per string; lead/Ni-Cd 70 kWh. Exceeding triggers Group H-2.

Page 61 – Flow-battery primer

Depicts redox flow cell with pumps, bipolar plates, membranes; suited for PV/wind, regen, standby, prime power.

Page 62 – Benefits summary

• Excellent vs. single-string VLA/Ni-Cd: cycling, temp range, rapid recharge, size/weight, predictable life (12-15 yr “maintenance-free”), built-in BMS & TR control, shelf life.

Page 63 – Best application niches

• Single-string replacements
• Engine-gen start
• Switchgear/process control
• Wind / PV storage
• <5 min UPS
• Flicker & voltage control.

Page 64 – Large BESS container concept

Container with HVAC/liquid cooling; modifiable racks; controller handles charge, balancing, SOC targets, active/reactive power, protection, DC contactors. NFPA 850 §4.4.3.2: if ≥100 ft from occupancies, water supply & suppression can be omitted (AHJ discretion). Max dims 45 × 8 × 9.5 ft.

Page 65 – Large-power BESS benefits (18 MWh example)

Super cycling, fast recharge, no building code compliance (remote), high/low T capable, compact, 12-15 yr life, full monitoring. Ideal for renewables & grid services.

Page 66 – Utility interconnection compliance

UL 9540, UL 1741 SA or CSA 107.1, IEEE 1547 series, NERC PRC-024-1 as applicable.

Page 67 – Overall limitations (recap)

Codes & best-practice lag, charger compatibility, external DC breaker for >3 cabinets, replacement compatibility, MAQ & 36 in clearances, evolving suppression rules, DOT transport, proprietary sizing tools, high initial cost.

Page 68 – Additional limitations

Electronics not as temperature-rugged as batteries, NFPA 850 capacity/size limits, shipping batteries loose → requires certified installers.

Page 69 – Generic recharge curve

Illustrates CC/CV charge; current tapers to “end-of-charge current”; 100 % returned at T_final; float voltage indicated.

Page 70 – Classical thermal-runaway diagram

Shows elevated battery temperature causing runaway during charge; underscores need for BMS cut-off & cooling.