CARBON ADDITIVES IN ADVANCED LEAD ACID BATTERIES: SOLUTIONS AND OPPORTUNITIES

Transcription

1 CARBON ADDITIVES IN ADVANCED LEAD ACID BATTERIES: SOLUTIONS AND OPPORTUNITIES Paolina Atanassova 1, Aurelien DuPasquier 1, Miki Oljaca 1, Plamen Nikolov 2, Maria Matrakova 2, Detchko Pavlov 2 1 Cabot Corporation, Billerica, Massachusetts, USA 2 Institute of Electrochemistry and Energy Systems (IEES), Sofia, Bulgaria 10 th International Conference LABAT 2017, Golden Sands, Bulgaria, June 13-16, 2017

2 Market Adoption of Carbon Additives Lead acid batteries are currently dominating microhybrids and storage applications due to low cost and existing broad manufacturing infrastructure, but threat from lithium is very real and growing Carbon additives are a critical part of the solution for improved performance of lead acid batteries and gaining market adoption, but formulation optimization is needed Often less than 1% additive to negative mass can bridge key performance gaps like dynamic charge acceptance and cycle life, but issues with meeting existing water consumption tests had to be addressed Carbon additives provide solutions and new learnings open further opportunities 2

3 Cabot s Energy Materials Business Part of Performance Chemicals business Located at our Billerica, MA Business and Technical Center Focus is energy storage applications Lithium ion, lead acid, supercapacitors, fuel cell, others Performance additives for energy storage applications Carbon black, activated carbon, fumed silica, fumed alumina and graphenes Neat and formulated systems Dedicated Applications and R&D groups Cell making and testing Leverage full capabilities of Cabot for product and material developments 3

4 PBX Additive Properties and Typical Applications 0.25% PBX % PBX51

5 High and Controlled Purity of PBX Carbon Additives PBX products produced at scale, impurities part of COA PBX 135 carbon additive typical values* Property Test Method Unit Value BET Nitrogen surface area ASTM D6556 m 2 /g OAN ASTM D2414 ml/100g Iron Internal method ppm <20 Total Co, Cr, Cu, Fe, Mn, Ni Internal method General Characteristics Formula: Carbon Aspect: Carbon black pellets CAS Number: ppm <40 *The data in the table above are typical test values intended as guidance only, and are not product specifications. Standard Packaging 5 kg bags Focus on metals which have strong influence on hydrogen evolution 5

6 New PBX 300G Graphene-based Additive 1 µ Incorporation in negative paste at loading of % loading can improved cycle life in deep discharge applications Maintain high discharge rates at low temperatures Battery applications: E-bikes Energy Storage Micro hybrid vehicles 10kg containers 6

7 Carbon Blacks Most Widely Used in Advanced Lead Acid Batteries Activated carbons Aerogels Carbon blacks Nanofibers Fibers Graphenes 0.5µ Higher purity Superior performance 2µ Graphites Most widely used materials Large scale production Good performance Carbide-derived Nanotubes carbons Higher cost 10µ 7

8 Carbon Additives Enable Significant Improvements in Dynamic Charge Acceptance (DCA) and Cycle Life % improvement in DCA, and 3-10 times improvement in cycle life have been demonstrated on a cell and battery level Full spectrum of carbon s effects not completely known yet, but some performance effects are clear: Increased NAM surface area Capacitive contribution Additional nucleation sites Restriction of crystal growth S C carbon contact surface area with solution S NAM = S PB S PBSO4 + S C I charge /given current constant current I Tafel equation: Δφφ = αα + bb. lg D. Pavlov et all, J. Power Sources, 191 (2009) 58 SS PPPP SS PPPPPPOO 4 +SS CC 8

9 Carbon Type and Morphology of Negative Electrodes CB CB Pb Pb Pb Pb AC/G CB CB Pb Electrode with CB Electrode with AC or Graphene 1 µm 10 µm

10 Different Applications Require Different Solutions Reliable grid SLI Unreliable grid Time at Float Water Loss Grid Corrosion PAM Failure PSoC: NAM Sulfation Traction/ Forklifts µ HEV E-bikes Time Cycling/ Depth of Discharge 10

11 NAM Surface Area Depends on Carbon Type and Loading 1% PBX09 Pb Carbons vary in morphology (size and shape), 0.25% surface area and surface properties PBX51 The theoretical NAM surface area is calculated by the following formula: 0.5% PBX135 1% PBX135 1% PBX09 Carbon BET * Carbon wt. % + Lead BET * Lead wt.% = Theoretical NAM BET [m 2 /g] For Carbon with BET = 1000 m 2 /g: 1000 * *0.99 = = m 2 /g or approximately 10.5 m 2 /g NAM porosity and pore size distribution are also important Pb factors determining DCA, cycle life and low temperature discharge performance 11

12 High Rate Partial State of Charge Cycling vs. NAM Area 1% PBX 09 (1.4m 2 /g NAM) #cycles Control 2,329 PBX51_1% 15,104 PBX09_1% 6,583 HRPSoC Cycling 4.8Ah AGM Cell 5% DOD with 3C rate 50% SOC 2.83V - 1.7V Control (0.5m 2 /g NAM) 1% PBX 51 (7.8m 2 /g NAM ) 12

13 Cell voltage / V Effect of Carbon Blacks on 50% DoD Cycling % Carbon 0.5% PBX51 1.0% PBX09 Discharge C/10 A down to 80% SoC Discharge with C/2 down to 30% SoC Charge with C/2 to 30% SoC After 6 cycles, 12h charge with C/10 Above combined: one cycling unit, 32h Time / h Control (0% carbon) 16 cycling units PBX 135 (0.5% and 1%), PBX09 (1%) 18 cycling units PBX 51 (0.5%) 25 cycling units End of life: V<1.7V 13

14 Synergistic Effect of Combined CB and AC 3.0 Cell voltage / V % Carbon 0.5% PBX % ABG % PBX % ABG % PBX % PBX101 Time / h PBX 135 (0.5%) 18 cycling units ABG 1010 (1%) 28 cycling units PBX 135 (0.5%) + 1% ABG units PBX 135 (0.5%) + 1% PBX units Discharge C/10 A down to 80% SoC Discharge with C/2 down to 30% SoC Charge with C/2 to 30% SoC After 6 cycles, 12h charge with C/10 Above combined: 1 cycling unit, 32h End of life: V<1.7V 14

15 Optimal NAM Morphology Depends on Application Combination of high NAM surface area and pore size <2µ is beneficial for HRPSoC cycling, while high NAM surface area and pore size >2µ are best for deep cycling applications. 15

16 New PBX Additives Aim to Offer Tailored Solutions New PBX PBX 300G Increased performance at various operating conditions of power, cycling and reliability protocols Increased charge acceptance and cycle life while maintaining low water loss at high temperature operation Morphology and surface properties of carbon can be controlled to maximize performance benefit and minimize hydrogen evolution and water loss 16

17 Acknowledgements Cabot Corporation, USA Institute of Electrochemistry and Energy Systems - BAS, Bulgaria Thank you for your attention! The data and conclusions contained herein are based on work believed to be reliable, however, Cabot cannot and does not guarantee that similar results and/or conclusions will be obtained by others. This information is provided as a convenience and for informational purposes only. No guarantee or warranty as to this information, or any product to which it relates, is given or implied. This information may contain inaccuracies, errors or omissions and CABOT DISCLAIMS ALL WARRANTIES EXPRESS OR IMPLIED, INCLUDING MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE AS TO (i) SUCH INFORMATION, (ii) ANY PRODUCT OR (iii) INTELLECTUAL PROPERTY INFRINGEMENT. In no event is Cabot responsible for, and Cabot does not accept and hereby disclaims liability for, any damages whatsoever in connection with the use of or reliance on this information or any product to which it relates Cabot Corporation.