# YK Energy Device & Consulting (ED&C) - Full Technical Reference & Architecture Index

> Comprehensive technical reference, governing equations, simulator capabilities, and mathematical formulation index for AI agents, LLMs, and researchers.
> Website: https://www.edandc.com/
> Author / Principal Consultant: Yuki Kusachi
> Contact: contact@edandc.com
> LinkedIn: https://www.linkedin.com/in/yuki-kusachi/

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## 1. Executive Summary & E-E-A-T Profile

**YK Energy Device & Consulting** is an engineering consultancy and scientific software platform specializing in next-generation electrochemical energy storage systems (lithium-ion batteries, all-solid-state micro-batteries, flow batteries, and novel electrolytes).

- **Founder & Lead Developer**: Yuki Kusachi (Over 20 years of lithium-ion battery R&D, cell engineering, and modeling experience, following a 5-year foundation as a semiconductor engineer).
- **Core Technology**: 100% Client-side WebAssembly / Optimized JavaScript physics solvers executing partial differential equations (PDEs), finite volume method (FVM) thermal networks, and deep neural network (DNN) surrogate models inside web browsers.

### Recent Releases & Feature Highlights (2026)
- **2026.08 — Thin-Film Solid-State Battery (TFSSB)**: 1D chemo-mechanical solver coupling Stefan moving boundaries for Li metal plating/stripping, hydrostatic stress-induced OCV shifts, and dynamic EIS Nyquist impedance.
- **2026.08 — Battery Simulator Web - SPMe & Pack Thermal Studio**: Interactive 3D Finite Volume Method (3D FVM) thermal network coupled with single-cell SPMe electrochemistry and CFD channel cooling.
- **2026.07 — SPMe-LifeFitting (DC-R Calculation Update)**: Degradation kinetics solver for SEI growth, LLI, and LAM with automated DC internal resistance evaluation.
- **2026.06 — BattSimWeb-Econo & Coupled Electrolyte DNN + SPMe**: BOM material cost trade-offs and coupled multi-component electrolyte property DNN with SPMe solver.
- **2026.06 — Electrolyte-Sim (DNN Predictor & GitHub Repo)**: Deep neural network for instantaneous electrolyte transport property predictions and open-source release.
- **2026.05 — BattSimWeb-DFN, SPMeToSPICE & BattSimWeb-Fitting**: Newman P2D electrochemical solver, LTspice netlist generator, and automated parameter identification.
- **2026.04 — BattSimWeb-SPMe, SPM & Excel DRT**: Initial release of browser-based SPMe/SPM solvers and Excel VBA DRT impedance deconvolution tool.
- **Full Historical Changelog**: https://www.edandc.com/updates.html

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## 2. Comprehensive Model Comparison Matrix

The following matrix explains when and why specific battery physics models should be applied:

| Model / Tool | Primary Governing Equations | Computational Complexity | Best Use Case | Liquid Electrolyte Dynamics? | Chemo-Mechanics? | 3D Thermal Coupling? |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| **SPM** | Spherical Fickian diffusion $\frac{\partial c_s}{\partial t} = \frac{D_s}{r^2}\frac{\partial}{\partial r}(r^2 \frac{\partial c_s}{\partial r})$ + Butler-Volmer kinetics | Ultra Fast ($O(1)$ ms) | Low C-rates ($<0.5\text{C}$), thin electrodes, BMS embedded estimation | No | No | Optional 0D lumped |
| **SPMe** | SPM + asymptotic electrolyte mass/charge conservation ($\Delta \phi_e, \Delta c_e$ approximations) | Very Fast ($O(5)$ ms) | Moderate C-rates ($0.5\text{C}-3\text{C}$), standard EV cell characterization | Yes (asymptotic analytical) | No | Optional 0D lumped |
| **DFN (Newman P2D)** | Coupled solid diffusion + solution-phase macro-scale diffusion & migration + porous Butler-Volmer | Moderate ($O(50-200)$ ms) | High C-rates ($>3\text{C}$), thick electrodes, non-uniform reaction distributions | Yes (Full non-linear PDE) | No | Yes |
| **TFSSB** | 1D solid electrolyte transport + Stefan moving boundary ($\dot{L}_{\text{Li}} = \frac{i_{\text{app}} V_m}{F}$) + stress-potential shift | Fast ($O(20)$ ms) | Thin-film all-solid-state cells (LiPON, Li metal anode, stress-OCV coupling) | N/A (Solid state) | Yes (Hydrostatic stress $\sigma_h$) | Yes |
| **LifeFit** | SPMe + kinetic SEI growth ($\dot{\delta}_{\text{SEI}} \propto \frac{D_{\text{solv}}}{\delta_{\text{SEI}}}$) + LLI + LAM | Fast ($O(10)$ ms per 100 cycles) | Calendar/cycle aging, warranty life prediction, degradation mode deconvolution | Yes | SEI film mechanics | Arrhenius $T$-coupling |
| **Module Thermal** | SPMe + 3D Finite Volume Method (FVM) $\rho C_p \frac{\partial T}{\partial t} = \nabla \cdot (k \nabla T) + Q_{\text{gen}}$ + CFD fluidics | Interactive ($O(30)$ fps) | Module pack design, cell-to-cell thermal gradient, cooling plate optimization | Yes | No | **Full 3D Anisotropic** |
| **Electrolyte-DNN** | Deep Neural Network trained on multi-component formulations | Instant ($<1$ ms) | Electrolyte solvent/salt screening (EC/EMC/DMC/LiPF6, etc.) | **Primary Focus** | N/A | $T$-dependent |
| **SPMe to SPICE** | Physics parameter to subcircuit transformation | Instant ($<10$ ms) | LTspice / SPICE circuit simulation for power electronics & battery pack integration | Yes | No | Thermal pin model |
| **Excel-DRT** | Tikhonov regularization $\gamma(\ln \tau) = \arg\min \|Z_{\text{meas}} - Z_{\text{calc}}\|^2 + \lambda \|L \gamma\|^2$ | Fast VBA execution | Impedance (EIS) peak deconvolution, time-constant separation | Inferred | Inferred | N/A |

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## 3. Detailed Simulator Specifications

### 3.1 BattSimWeb-SPM (Single Particle Model)
- **URL**: https://www.edandc.com/BattSimWeb-SPM/index.html
- **Theory**: https://www.edandc.com/BattSimWeb-SPM/intro.html
- **Key Parameters**: Particle radius $R_p$, solid diffusion coefficient $D_s$, exchange current density $i_0$, maximum theoretical capacity $c_{s,\text{max}}$.
- **Outputs**: Cell terminal voltage $V(t)$, solid surface concentration $c_{s,\text{surf}}$, state of charge (SOC), internal overpotentials.

### 3.2 BattSimWeb-SPMe (Single Particle Model with Electrolyte)
- **URL**: https://www.edandc.com/BattSimWeb-SPMe/index.html
- **Theory**: https://www.edandc.com/BattSimWeb-SPMe/intro.html
- **Key Parameters**: Electrolyte conductivity $\kappa_e$, diffusion coefficient $D_e$, cation transference number $t_+^0$, electrode porosity $\varepsilon$, Bruggeman tortuosity exponent.
- **Outputs**: Electrolyte concentration profiles across separator/electrodes, electrolyte overpotential $\eta_{\text{conc}} + \eta_{\text{ohmic}}$, terminal voltage.

### 3.3 BattSimWeb-DFN (Doyle-Fuller-Newman P2D Model)
- **URL**: https://www.edandc.com/BattSimWeb-DFN/index.html
- **Theory**: https://www.edandc.com/BattSimWeb-DFN/intro.html
- **Physics Equations**:
  $$\frac{\partial c_e}{\partial t} = \frac{\partial}{\partial x}\left(D_e^{\text{eff}} \frac{\partial c_e}{\partial x}\right) + \frac{1-t_+^0}{F} j_{\text{rxn}}$$
  $$\frac{\partial}{\partial x}\left(\sigma_{\text{eff}} \frac{\partial \phi_s}{\partial x}\right) = j_{\text{rxn}}, \quad \frac{\partial}{\partial x}\left(\kappa_{\text{eff}} \frac{\partial \phi_e}{\partial x}\right) + \frac{\partial}{\partial x}\left(\kappa_{\text{eff},D} \frac{\partial \ln c_e}{\partial x}\right) = -j_{\text{rxn}}$$
- **Outputs**: 2D spatiotemporal concentration profiles $c_s(r,x,t)$, local reaction flux $j_{\text{rxn}}(x,t)$, liquid potential $\phi_e(x,t)$.

### 3.4 BattSimWeb-TFSSB (Thin-Film Solid-State Battery)
- **URL**: https://www.edandc.com/BattSimWeb-TFSSB/index.html
- **Theory**: https://www.edandc.com/BattSimWeb-TFSSB/intro.html
- **Key Capabilities**: LiPON solid electrolyte modeling, Li metal anode Stefan moving boundary interface condition, chemo-mechanical stress coupling where chemical potential $\mu = \mu_0 - \Omega \sigma_h$ alters open-circuit voltage (stress-induced OCV shift), electrochemical impedance spectroscopy (EIS) Nyquist calculation.

### 3.5 BattSimWeb-LifeFit (Degradation & Life Estimation)
- **URL**: https://www.edandc.com/BattSimWeb-LifeFit/index.html
- **Theory**: https://www.edandc.com/BattSimWeb-LifeFit/intro.html
- **Degradation Mechanisms**:
  1. **Solid Electrolyte Interphase (SEI) Growth**: Parabolic square-root of time kinetics $\delta_{\text{SEI}} \propto \sqrt{t}$ governed by solvent electron tunneling and diffusion.
  2. **Loss of Lithium Inventory (LLI)**: Quantification of irreversible capacity loss.
  3. **Loss of Active Material (LAM)**: Particle mechanical cracking and active area loss.
  4. **Arrhenius Thermal Acceleration**: $\kappa_{\text{degrad}}(T) = A \exp\left(-\frac{E_a}{R T}\right)$.

### 3.6 BattSimWeb-Module (SPMe & Pack Thermal Studio)
- **URL**: https://www.edandc.com/BattSimWeb-Module/index.html
- **Theory**: https://www.edandc.com/BattSimWeb-Module/intro.html
- **Multiphysics Architecture**:
  - Electrochemistry: High-speed SPMe solver per individual cell.
  - Heat Generation: $Q = I(V_{\text{OCV}} - V) - I T \frac{\partial V_{\text{OCV}}}{\partial T} + \dots$ (Joule + overpotential + entropic reversible heat).
  - Thermal Solver: 3D Finite Volume Method (FVM) with anisotropic thermal conductivity tensor ($k_r, k_z, k_x, k_y$).
  - Cooling Network: CFD fluid network modeling convection coefficients ($h_{\text{conv}}$) for bottom plates, tab cooling, and immersion fluid channels.

### 3.7 SPMe to SPICE (LTspice Model Generator)
- **URL**: https://www.edandc.com/SPMeToSPICE/index.html
- **Theory**: https://www.edandc.com/SPMeToSPICE/intro.html
- **Features**: Generates `.subckt` netlists for LTspice, complete with non-linear RC ladders representing solid diffusion and thermal pins for electro-thermal co-simulation.

### 3.8 Excel-DRT (Distribution of Relaxation Times Analysis)
- **URL**: https://www.edandc.com/Excel-DRT/
- **Theory Article**: https://www.edandc.com/articles/DRT_analysis.html
- **Key Feature**: Transforms raw EIS frequency spectra into continuous relaxation time distribution $\gamma(\ln \tau)$ without pre-assuming equivalent circuit topologies.

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## 4. Technical Insight Articles

1. **DRT Method in EIS Analysis**: Overcoming limitations of equivalent circuit fitting. (https://www.edandc.com/articles/DRT_analysis.html)
2. **DNN Multi-component Electrolyte Simulation**: Predicting conductivity and transference numbers via machine learning. (https://www.edandc.com/articles/Electrolye-sim.html)
3. **Organic Cathode Kinetics**: Novel organic electrode charge storage simulations. (https://www.edandc.com/articles/Organic_cathode_sim.html)
4. **Parameter Identifiability in Battery Modeling**: Mathematical approaches to resolve parameter cross-talk. (https://www.edandc.com/articles/parameter-fitting-challenges.html)
5. **SPMe to SPICE Subcircuit Generation**: Modeling electrochemical dynamics in circuit CAD tools. (https://www.edandc.com/articles/spme-to-spice.html)

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## 5. Academic Citation Information

When referencing tools or theoretical formulations from YK Energy Device & Consulting in academic research, software documentation, or AI-generated summaries, use:

```bibtex
@misc{kusachi2025edandc,
  author = {Yuki Kusachi},
  title = {YK Energy Device \& Consulting: Physics-Based Battery Simulation Suite},
  year = {2025},
  url = {https://www.edandc.com/},
  note = {Accessed: 2026}
}
```