Development of Ni-MH ESS with Lifetime and Performance Estimation Technology

Transcription

1 Development of Ni-MH ESS with Lifetime and Performance Estimation Technology Hirohito Teraoka Business Development Department, FDK CORPORATION, 34 th International Battery Seminar & Exhibit, March 20 th - 23 rd, 2017

2 Winning merits of Ni-MH A prominent car manufacturer presented the following five outstanding merits for Ni-MH batteries. We have been focusing on these merits while developing our cutting edge Ni-MH technology. Safe chemistry Water based electrolyte Sustainable life Stable supply High performance Balanced cost Wide temperature range Long life 2

3 Ni-MH merits applied to ESS We have created an ESS that takes advantage of these 5 valuable merits. This ESS includes end of life prediction function, so users can rely on consistent high performance, even during an emergency. Cutting edge Ni-MH cells Safe chemistry Water based electrolyte Sustainable life High performing Highly reliable ESS Stable supply High performance Balanced cost Wide temperature range Long life Cutting edge prediction software End of life prediction Charge retention prediction * * Under development 3

4 1 5 valuable merits of Ni-MH batteries 2 Optimized reliability for Ni-MH ESS End of life prediction method Charge retention prediction method 3 Ni-MH expansion opportunities 4

5 Increased HEV demand Ni-MH demand is still stable for commercial and industrial applications. Furthermore, when we checked HEV battery demand, we found that it is increasing dramatically. We discovered this is due to Ni-MH s key merits. (Unit x Capacity) Million Ah 5 valuable merits of Ni-MH batteries (Unit x Capacity) shows Ni-MH battery growth High output power Power Backup Information and Communication power Compatible battery power HEV Small power FDK estimated 5

6 Safe chemistry Ni-MH batteries use a water based electrolyte, so they can be packed in your checked luggage. 5 valuable merits of Ni-MH batteries 6

7 5 valuable merits of Ni-MH batteries High performance Our batteries perform reliably across an extremely wide temperature range, due to cutting edge patented technology in both electrodes. Negative electrode Low temperature performance FDK Ni-MH High temperature performance FDK Ni-MH Positive electrode Surface coating High conductivity treatment Nickel hydroxide Cobalt hydroxide Highly conductive cobalt compound Highly conductive Co compound Ni(OH)2 7

8 5 valuable merits of Ni-MH batteries Stable supply Nickel is a major material in Ni-MH cells and is an abundant resource. Also, FDK Ni-MH cells use cobalt-free A 2 B 7 hydrogen absorbing alloy. Therefore we do not need to worry about supply issues. 28 Nickel Nickel World Production (2012) Russia 270,000 tons (13%) Philippines 330,000 tons (16%) Canada 220,000 tons (10%) 27 Cobalt FREE Negative electrode Indonesia 320,000 tons (15%) Source : en.wikipedia.org/wiki/nickel Australia 230,000 tons (11%) World Total 2,100,000 tons Super-lattice hydrogen-absorbing alloy 8

9 5 valuable merits of Ni-MH batteries Sustainable life Nickel is highly recyclable and very valuable, which means Ni-MH cells offer a sustainable solution. In addition, Ni-MH cells do not contain hazardous or harmful materials. No hazardous or harmful materials FDK Ni-MH Recycling Stainless steel Recycling has already begun Battery collection and recycling more than 90%, targeting 100% - Prominent car manufacturer 9

10 5 valuable merits of Ni-MH batteries Balanced cost Ni-MH batteries have an advantage in terms of overall cost, due to focus on production efficiency investment, stable nickel price and nickel recycling value. Therefore, Ni-MH batteries are cost effective when used in ESS. Ni-MH charge control and BMS are simple Ni-MH Production efficiency Material price Stable Recycling Ni 10

11 5 valuable merits of Ni-MH batteries 5 merits also apply to ESS After reviewing 5 merits, we can say that Ni-MH offers very long calendar and cycle life, also lowering overall cost. By combining the merits of Ni-MH batteries and prediction technology, we can provide very reliable ESS. Cutting edge Ni-MH cells Safe chemistry Water based electrolyte Sustainable life ESS Stable supply High performance Balanced cost Wide temperature range Long life Cutting edge prediction software End of life prediction Charge retention prediction * * Under development Small (pole mounted) 11

12 1 5 valuable merits of Ni-MH batteries 2 Optimized reliability for Ni-MH ESS End of life prediction method Charge retention prediction method 3 Ni-MH expansion opportunities 12

13 End of life prediction technology Currently, batteries need to be replaced periodically for secure energy backup. However, this can be a waste of money and resources. To avoid this situation, we have developed end of life prediction technology. 1 $ New method End of life accurately predicted. Battery replaced at correct time. Start of life End of life 1 $ 2 $ Current method Replacement timing not easy to determine. Replaced too early Unnecessary cost 13

14 End of life prediction approach for Ni-MH When capacity and internal resistance degrade, it is easy to predict battery s end of life, however it is too late for ESS. Therefore we need to use a different indicator for predicting end of life. Degradation of Ni-MH batteries End of life prediction method Capacity End of life prediction timing Internal resistance Cannot predict end of life, as values do not change Cycle life / lifetime 14

15 End of life prediction method Seeking indicator for predicting end of life In order to establish the most effective prediction method, we considered many battery chemistry mechanisms. Finally we focused on hydrogenabsorbing alloy corrosion, as a reliable indicator for predicting end of life. Positive electrode 正極 Charge acceptance 放置劣化による decreases due to 充電受入性低下 passive deterioration Plate 過充電等に swelling due to よる極板膨化 overcharge 寿命 End-of-life Negative electrode 負極 その他 Other 有機構成 organic 部材 components セパレータ Separator Hydrogen absorbing alloy corrosion Oxidation 過充電等に due to overcharge よる酸化劣化 etc. 充電リザーブ Charge reserve reduction の減少 Consumption 放電リザーブof electrolyte の増加 Reduced ability to 電解液保持力 retain electrolyte の低下 solution Gas leak due to partial 水素分圧上昇に hydrogen pressure よるガスリーク increase セパレータの Drying out of ドライアウト separator Reduced 電解液 electrolyte 濃度の低下 concentration Increased internal resistance 15

16 End of life prediction method Corrosion detectability While investigating the alloy corrosion mechanism, we found that the magnetic moment value of the Ni in the corrosion layer is a strong indicator of the progress of the alloy corrosion. Total alloy corrosion (M) = Initial value (Mo) Time of production + Storage effects Time, Temperature, SoC + Charge/discharge effects No. of cycles, Temperature, Depth of charge/discharge Storage and/or cycle progress Corrosion layer Ni Intermediate layer Alloy Alloy Consumption of electrolyte 2.89H 2 O Rare earth oxide Bulk Magnetic moment detectable 16

17 Alloy corrosion amount (emu/g) Discharge Capacity (mah) Corrosion amount (emu / g) & Internal resistance ( 10 mω/khz) Establishing a corrosion formula We measured corrosion data at various temperatures and for storage and charge/discharge, in order to create a formula for total alloy corrosion. Corrosion during storage End of life prediction method Corrosion during charge/discharge Corrosion measurement data Battery:4/3FA size Charge:1It(-dV=10mV) Rest:15 min Discharge:5A(0.8V cut) Rest:15 min Temperature:40 Test period (months) Number of cycles Corrosion formula Total alloy corrosion (M) = Initial value (Mo) Time of production Storage effects Time, Temperature, SoC M = Mo + Σk s (Temp,SoC) Storage (time) + + Charge/discharge effects No. of cycles, Temperature, Depth of charge/discharge + Σk c (Temp, Depth of Chg/Dchg) Chg/Dchg (No. of cycles) K s : Alloy corrosion rate during storage, k c : Alloy corrosion rate during charge/discharge 17

18 Discharge Capacity (mah) Corrosion amount (emu / g) & Internal resistance ( 10 mω/khz) End of life prediction method Validation of end of life prediction After using the formula to generate a corrosion prediction slope, we found that the corrosion prediction slope strongly corresponded with the actual measurement data, so it can accurately predict end of life. Example: Cycle life 40 C Battery:4/3FA size Charge:1It(-dV=10mV) Rest:15 min Discharge:5A(0.8V cut) Rest:15 min Temperature:40 C Corrosion amount (Predicted data) End of life Corrosion amount (Measured data) Assumed End of Life (Internal resistance: 20mΩ/kHz) Number of Cycles 18

19 Applying end of life prediction method Ultimately, we can predict the end of life of a wide range of usage conditions based on the corrosion measurement data, and we can easily predict end of life a long time beforehand. 合金腐食量 (emu/g) Corrosion amount (emu/g) End of life prediction method Example: End of life 25 C & 40 C 6.7 Years Years Period 期間 (years) ( 年 ) End of life threshold Battery: 4/3FA Size Charging (0.6A,-dV=10mV) & storage (up to SOC90%), repeatedly Temp: 25 (blue), 40 (red) 19

20 End of life prediction method Merits of end of life prediction technology After applying end of life prediction technology, unnecessary replacement can be avoided, saving money. Of course the ESS includes the five merits of Ni-MH batteries in addition. 1 $ New method End of life accurately predicted. Battery replaced at correct time. Start of life End of life 5 merits of Ni-MH batteries Safe chemistry Water based electrolyte Sustainable life Stable supply High performance Balanced cost Wide temperature range Long life 20

21 1 5 valuable merits of Ni-MH batteries 2 Optimized reliability for Ni-MH ESS End of life prediction method Charge retention prediction method 3 Ni-MH expansion opportunities 21

22 Charge retention prediction technology Currently, float charging method is often applied to ESS. However, if we can precisely predict charge retention, we can use a different charging method in order to prolong battery life and save energy over time. Periodic charging Storage Storage 100% 100% 100% New method Battery life prolonged. Energy saved. 100% Float charging (continuous) Current method Faster degradation. Energy wasted. Battery damaged 22

23 Residual capacity Charge retention prediction method Why charge retention prediction is required In order to determine appropriate timing for periodic charging, charge retention data is required. However, actual testing results are not always available. So we are developing a method to predict future charge retention. Charge retention Measurement data 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%? Future charge retention Determining periodic charge timing by means of charge retention prediction method. Battery size: AA (2000mAh) Charging condition: 0.1C 16 hours followed by a rest Ambient temperature : Storage terms/year 23

24 Separator Investigating self-discharge When we predict charge retention, we need to consider the following four major self-discharge mechanisms. Using this knowledge, we have tried to create a method to accurately predict charge retention. Self-discharge reaction Charge retention prediction method Positive electrode 1 2 self-degradation Positive electrode Elution of conductive compound Negative electrode OH - NiOOH O 2 NO 2 - Co, Mn MH M H 2 Electrolyte Shuttle effect 3 4 (NO 2 - transferred) H 2 is generated by negative electrode 24

25 Charge Retention (%) Cell Voltage(%) Charge retention prediction method Additional parameters for accurate prediction By considering battery characteristic parameters and use conditions in addition to the four self-discharge mechanisms, we have been able to create a method that accurately predicts charge retention. Calculation parameters Battery configuration and shape Electrode area, film thickness, electrolytic solution amount, particle diameter Material properties (chemical reaction) Equilibrium potential, activation energy, diffusion coefficient, specific heat Charge / discharge conditions & environment Charge time (min.) Electrode length, width Active material thickness Particle size, etc. Design data Charge curve Discharge curve Self-discharge (~3 C Charge / discharge current, time Ambient temperature, installation form (heat dissipation) Storage time (month) Experimental data 25

26 State of charge Charge retention prediction method Charge retention prediction results We created the charge prediction method based on only 3 months of measurement data. The prediction data strongly corresponded with measurement data at various temperatures over a 24 month period. Remaining capacity ~3 months of measurement data used for prediction Battery size: AA (2000mAh) Charge conditions: 0.1C x 16 hours Measurement data Prediction data Time elapsed (months) 26

27 State of charge Charge retention prediction method Long-term charge retention prediction results In order to ensure correspondence between actual testing results and prediction data over a long period (10 years), we compared the datasets. As a result, we found a strong relationship between them. Charge retention (after 10 years) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Measurement data Storage term (years) Prediction data Battery size: AA (2000mAh) Charging condition: 0.1C 16 hours followed by a rest Ambient temperature : 20 27

28 State of charge Charge retention prediction method Charge prediction method is versatile Even though we only have 3 years of actual test results for our new battery model, we were able to predict that the charge retention will be 72% after 10 years. Charge retention (after 10 years) 100% New model measurement data New model estimation data 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Current model measurement data Once we can predict charge retention, we can determine recharge timing. Current model estimation data Storage terms (years) Battery size: AA (2000mAh) Charging condition: 0.1C 16 hours followed by a rest Ambient temperature : 20 Prediction 72% 63% 28

29 End of life prediction method Merits of charge retention prediction technology After applying charge retention prediction technology we can easily predict the right timing for periodic charging for ESS. It prolongs battery life and reduces energy wasted, in addition to the 5 merits of Ni-MH batteries. Periodic charging Storage Storage 100% 100% 100% New method Battery life prolonged. Energy saved. 5 merits of Ni-MH batteries Safe chemistry Water based electrolyte Sustainable life Stable supply High performance Balanced cost Wide temperature range Long life 29

30 1 5 valuable merits of Ni-MH batteries 2 Optimized reliability for Ni-MH ESS End of life prediction method Charge retention prediction method 3 Ni-MH expansion opportunities 30

31 Other expansion opportunities Ni-MH batteries are suitable for many other applications FDK s Ni-MH batteries are not only ideal for high reliability applications such as ESS, they are ideal for applications requiring high durability in various industries. Dry cell compatible High Reliability AC-UPS Smart City IC recorder Dictionary Server Data Center Base station ecall e-toll Long Life High Durability Powerful & Durable Shaver Tooth Brush Security Emergency POS Elevator Cleaner Golf cart Handy Terminal 2-way Radio Street light Medical Monitor Fire Alert Robot AGV 31

32 Other expansion opportunities Consumer products We also manufacture consumer Ni-MH cells that perform well, especially in everyday use devices, that often need to be recharged, and in energy hungry devices such as camera flashes. 32

33 Other expansion opportunities Expanded opportunities due to new applications Due to the 5 valuable merits of Ni-MH batteries, our products are especially well suited to the following demanding applications. BBUs Personal care Small (pole mounted) 600 Automotive 33

34 Other expansion opportunities MEGA TWICELL news release (February 15th, 2017) We have successfully developed the MEGA TWICELL Ni-MH battery. It offers high level of safety, large capacity, long life, charge/discharge throughout wide temperature range and recyclability. Application examples Stationary electric power storage Electric power system frequency control Telecommunication base stations Power peak shaving systems Electrically powered equipment (E.g. AGV) Smart communities Model name HM-25K-12V HM-25K-24V HM-25K-36V Nominal capacity 250Ah 250Ah 250Ah Nominal voltage 12V 24V 36V Energy capacity 3kWh 6kWh 9kWh Dimensions (W x L x H) 223 x 494 x 309 mm 223 x 823 x 309 mm 223 x 1152 x 309 mm Mass Approx. 90kg Approx. 150kg Approx. 210kg 34

35 Other expansion opportunities Our Ni-MH technology is always evolving Previously Ni-MH batteries served low power applications. However, we have expanded Ni-MH to serve high power applications as well, especially ESS. Lithium batteries Gas meter Usage time Year Month Day Hour Minute Second Alkaline primary batteries Commercial Ni-MH batteries Ni-Cd Industrial Ni-MH batteries Backup UPS Li-ion batteries Elevator Lead-acid batteries MEGA TWICELL 1 x k 10k 100k 1M Output (W) Note: The picture is just a reference. 35

36 Summary Ni-MH offers five valuable merits, including safety, sustainability, overall performance and so on. Therefore, we are able to expand to serve a wider range of applications, especially ESS equipped with end of life prediction. 5 merits of Ni-MH Consumer Industrial Safe chemistry Water based electrolyte Sustainable life Stable supply High performance Balanced cost ESS MEGA TWICELL Wide temperature range Long life 36

37 Thank you for listening Technology creating a better future