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# Redox Flow batteries at CEA-Liten: Test facilities, some examples of characterization and feedback

Nicolas Guillet, Jean-Marie Klein

► To cite this version:

Nicolas Guillet, Jean-Marie Klein. Redox Flow batteries at CEA-Liten: Test facilities, some examples of characterization and feedback. Annual Scientific Meeting of the GDR RFB, Groupement De Recherche Redox Flow – GDR2070, Nov 2021, Paris, France. cea-04202846

HAL Id: cea-04202846

https://cea.hal.science/cea-04202846

Submitted on 11 Sep 2023

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# REDOX FLOW BATTERIES AT CEA-LITEN: TEST FACILITIES, SOME EXAMPLES OF CHARACTERIZATION AND FEEDBACK

Annual Scientific Meeting of the GDR RFB, 3 and 4 November 2021 – Paris

| Nicolas Guillet

Nicolas GUILLET & Jean-Marie KLEIN

Univ. Grenoble Alpes, CEA, Liten, Campus Ines, 73375 Le Bourget du Lac, France

ines
NATIONAL INSTITUTE
OF SOLAR ENERGY
# INES CAMPUS : PRESENTATION & TESTS FACILITIES

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## Institut National de l'Energie Solaire (INES)

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~ 450-500 persons

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~ 70 patents per year

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200 industrial partners

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Budget ~ 60 M€

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## Photovoltaic

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material
cells
modules
equipment
process

## Systems

software
electronics
storage
grid
mobility & loading

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## Building

thermal systems
envelope
management

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ELECTROCHMICAL STORAGE OF ENERGY

* Three mains domains addressed by the laboratory

Stand-alone
systems

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Grid-connected
systems

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Building integration

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* Selection of the most appropriate battery

* Definition of advanced management strategies
# TESTS FACILITIES AT INES CAMPUS

* Tests & characterization of batteries

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* Small size (up to 20 V, 10 to 800 A) → 280 channels

* Module size (up to 150 V and 800 A) → 40 channels

* Pack size (up to 800 V and 600 A – 250 kW max) → 12 channels

* Battery monitoring & management

## Benchmarking

- Performance

- Durability

- Safety

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## Ageing modelling

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## Management algorithms

Optimization of operating strategies

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# TESTS FACILITIES AT INES CAMPUS

* EMS microgrid platform

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## Objectives

* ✓ Functional tests on equipments

* ✓ EMS algorithms development and validation

* ✓ Smart Charging tests/ V2G / V2H

* 170 kVA connection to "Public Grid"

* 6 AC LV Bus bars (400 VAC)

* 45 kVA AC Grid simulation

* 3 Ph 120V-690V

* 0-2500 Hz fundamental / Up to 50 kHz Harmonics

* PHIL Simulations

* BESS characterization and control development

* 3 test channels for BESS (on/off grid)

* Up to 250A @400V

* 600A Bus bar with islanding capabilities

* 110 kWc configurable PV fields

* 120 kWc PV simulation

* 100 kW batteries simulation

* ...
* Lead soluble - methanesulfonic acid type redox battery – Pb-MSA (Lab. scale)

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$$ \text{Pb}^{2+}_{(\text{aq})} + 2 \text{H}_2\text{O} \leftrightarrow \text{PbO}_{2(\text{s})} + 4 \text{H}^+ + 2\text{e}^- \quad (\text{E}_0=1.46 \text{ V vs. SHE}) $$

$$ \text{Pb}^{2+}_{(\text{aq})} + 2\text{e}^- \leftrightarrow \text{Pb}_{(\text{s})} \quad (\text{E}_0=-0.13 \text{ V vs. SHE}) $$

$$ \text{Pb}^{2+}_{(\text{aq})} + 2 \text{H}_2\text{O} \leftrightarrow \text{PbO}_{2(\text{s})} + \text{Pb}_{(\text{s})} + 4 \text{H}^+ $$

OCV ~ 1.6 V, solubility of Pb(CH₃SO₂)₂ in MSA ~ 2 mol/L

* **Advantages :**

- High theoretical active lead fraction (> 80 %)

- Membraneless (low cost)

- Solid $\leftrightarrow$ aqueous species reaction : no solid phase evolution

* **Hurdles :**

- Low kinetic of PbO₂/Pb²⁺ couple; high overpotentials

- Incomplete reduction of PbO₂; build-up of PbO₂ at both electrodes

- Poor PbO₂ adherence; loss of PbO₂ particles in the electrolyte
* Lead soluble - methanesulfonic acid type redox battery – Pb-MSA (Lab. scale)

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Oury et al. / Electrochimica Acta 71 (2012) 140–149
http://dx.doi.org/10.1016/j.electacta.2012.03.116

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* Limitations:

- $O_2$ evolution during charge

- Irreversible old state reaction $PbO_2 \rightleftharpoons PbO_x$

- $PbO_x$ acts as a passivation layer when $[H^+] > 1mol/L$
• Zinc – Bromine (Redflow)

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Power / energy capacity : 5 kW (7.5 kW peak) / 11 kWh

Voltage application : 53 Vdc

Net energy efficiency : 80% DC–DC Max

**Dimensions / weight**

845 L x 823 H x 400 W (mm)

90 kg without electrolyte

240 kg with electrolyte (100L)

Internal operating temperature : 10–50 °C

$$
\text{Positive :} \quad \mathrm{Br}_2 + 2 \mathrm{e}^- \leftrightarrow 2 \mathrm{Br}^- \qquad \mathrm{Q}(\mathrm{Br}^-)_{\mathrm{aq}} + n \mathrm{Br}_2 \leftrightarrow \mathrm{Q}(\mathrm{Br}_2)_n \mathrm{Br}^-_{\mathrm{aq}}
$$

$$
\text{Negative :} \quad \mathrm{Zn} \leftrightarrow \mathrm{Zn}^{2+} + 2 \mathrm{e}^{-}
$$

$$
\frac{\text{Br}_2 + \text{Zn} \rightarrow 2 \text{Br}^- + \text{Zn}^{2+}}{
$$

<figure><img src="image_37.png" /><figcaption>ENERGY - CAPACITY CURVES</figcaption></figure>

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• **Advantages** :

- Good specific energy density and round trip efficicy

- 100 % depth discharge available

• **Hurdles** :

- Self discharge

- Zinc dendrites formation
* Zinc – Bromine (Redflow)

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Power / energy capacity : 5 kW (7.5 kW peak) / 11 kWh

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* Zinc – Bromine (Redflow)

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Power / energy capacity : 5 kW (7.5 kW peak) / 11 kWh

* Efficiency:

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* Self discharge : SoC decreases linearly with time > 1 %/h at 25 °C

* Limitations: works very well but

- Balance of système is a major cost element

- System design and energy management system had to be improved

- Periodic self maintenance (minimum once every 72 hours of zinc pump operation)
* All Vanadium redox flow battery (VRB)

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$$ \text{Positive :} \quad \mathrm{VO}_2^{+} + 2 \mathrm{H}^{+} + \mathrm{e}^{-} \leftrightarrow \mathrm{VO}^{2+} + \mathrm{H}_2\mathrm{O} $$

$$ \text{Negative :} \quad \frac{\mathrm{V}^{2+} \leftrightarrow \mathrm{V}^{3+} + \mathrm{e}^{-}}{\mathrm{VO}_2^{+} + 2 \mathrm{H}^{+} + \mathrm{V}^{2+} \leftrightarrow \mathrm{VO}^{2+} + \mathrm{H}_2\mathrm{O} + \mathrm{V}^{3+}} $$

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Noak et al., 2020

* **Advantages :**

- Simple system

- 100 % depth discharge available

* **Hurdles :**

- Self-discharge

- Low specific density

- Cost of vanadium
* All Vanadium redox flow battery (VRB)

<table><thead><tr><th></th><th>Parameter</th><th>Data from supplier</th></tr></thead><tbody><tr><td rowspan="2">Performance</td><td>P charge nominale 15 - 80% SOC</td><td>10 kW DC<br>15 kVA onduleur</td></tr><tr><td>Nominal energy</td><td>100 kWh</td></tr><tr><td rowspan="2">Voltage output</td><td>AC voltage</td><td>400 V<sub>AC</sub></td></tr><tr><td>DC voltage range</td><td>36V<sub>DC</sub> - 63V<sub>DC</sub></td></tr><tr><td>Efficiency</td><td>Round trio DC efficiency</td><td>70-80%</td></tr><tr><td rowspan="2">Self-discharge</td><td>Within Cells</td><td>0,07 kW</td></tr><tr><td>Within tankks</td><td>Not significant</td></tr><tr><td rowspan="3">Weight & size</td><td>Size (mm)</td><td>4500*2200*2403</td></tr><tr><td>Empty mass</td><td>3500 kg</td></tr><tr><td>Mass with electrolyte</td><td>10300 kg</td></tr></tbody></table>

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* Cell: 1,2 V / 50 W

* Module (20 cells - 20S) : 24 V / 1 kW

* Battery (10 modules - 2S5P) : 48 V / 10 kW
# FEEDBACK ON SYSTEMS WITH VARYING DEGREES OF TECHNOLOGICAL MATURITY

* All Vanadium redox flow battery (VRB)

* Tests according to the DERri protocol http://www.der-lab.net/downloads/noe_003_grid_connected_storage.pdf

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Data often given by the supplier but have to be confirmed on the whole operation range

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Not or rarely available ; test to be conducted
# FEEDBACK ON SYSTEMS WITH VARYING DEGREES OF TECHNOLOGICAL MATURITY

* All Vanadium redox flow battery (VRB)

* Example of DERri test : State of Available Power (SoAP)

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Operation range limited to 0 – 80 % SoC by the BMS

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Power limitation with SoC (Umax)
* All Vanadium redox flow battery (VRB)

* Example of DERri test : one-way AC efficiency

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Low AC efficiency at low rcharge and discharge rates (auxiliaries)
* All Vanadium redox flow battery (VRB)

* Example of DERri test : time response

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<table><thead><tr><td>From / to</td><td>10 kW charge</td><td>10 kW discharge</td></tr></thead><tbody><tr><td>10 kW charge</td><td>-</td><td>10s</td></tr><tr><td>2kW charge</td><td>5s</td><td>7s</td></tr><tr><td>STOP</td><td>8s</td><td>8s</td></tr><tr><td>2 kW discharge</td><td>6s</td><td>5s</td></tr><tr><td>10 kW discharge</td><td>9s</td><td>-</td></tr></tbody></table>

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Time constants of few seconds
* All Vanadium redox flow battery (VRB)

* Onsite experiment (Projet AO CRE 2012 PV ZNI) : 500 days of operation

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* No evolution of performance during 500 days of operation

* No evolution of the DC efficiency but slight increase of the internal impedance

* 50% of operation points are at an efficiency lower than 50% → operation at low power
* All Vanadium redox flow battery (VRB)

**Conclusions over 3 years of evaluation**

- Strong deviation between standard datasheet and the real life

- Power limitations are mostly related to electrochemical phenomena

- Efficiency is lower than expected and is highly depending on the power request

- OPEX higher than expected (maintenance, electrolyte leak, pump failure...)

- Stable performance over 3 years while there was no temperature regulation of the battery

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CONCLUSIONS

* Stationary application storage and power grid management

* A complete ecosystem and experts in the field of electrochemical storage

* Characterization and evaluation of redox flow batteries of different levels of maturity

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liten
ceatech

Thank you for your attention !

Questions ?

nicolas.gilet@cea.fr