A New Generation of Paste Additive for Enhanced Flooded Batteries SHANDONG JINKELI POWER SOURCES TECHNOLOGY CO., LTD, CHINA

Transcription

1 A New Generation of Paste Additive for Enhanced Flooded Batteries SHANDONG JINKELI POWER SOURCES TECHNOLOGY CO., LTD, CHINA 1

2 As the number of urban motor vehicle grows, the amount of harmful carbon dioxide released into the atmosphere has increased significantly. In order to reduce vehicle exhaust emission and save oil, most of well-known car producers gradually use idle start/stop system for micro-hev. The vehicles with start/stop system can achieve better fuel economy with lower cost and lower emission. There are currently two types of lead-acid batteries for start/stop system: Enhanced flooded battery (EFB) and absorptive glass mat (AGM) battery. It is reported that there will be a rapid growth of AGM batteries, while such increase will occur from 2018 for EFB batteries and overpass the AGM batteries two years later. Comparing the performance of the two types of batteries, EFB has a bit lower performance on cold cranking ability, charge acceptance, deep discharge and cycle life under PSoC than AGM. Consequently, we ve been focusing on solving the above shortcomings of EFB through continuous selection, optimization and improvement of paste additives and successfully developed a new generation paste additive for EFB. This new generation additive will significantly improve the cold cranking, charge acceptance and cycle life of EFB. 2

3 Contents 1. Background and EFB battery used in HEV with start/stop function 2. Negative additive selection & trial Selection and test of ligninsulfonates Selection and test of carbon materials Selection and test of barium sulfates 3. Testing of cell with composite additive formula 4. Testing of EFB with composite additive formula 5. Conclusion 3

4 1. Background and EFB battery used in HEV with start/stop function 4

5 Trends of global automobile CO 2 emission 5

6 Carbon emission targets of vehicles for some countries and regions CO 2 emission g/km Deadline EU US Canada Japan China India New technologies including HEV and EV have been developed to achieve the above goals. 6

7 Trends of HEV sales in the world World Europe Source: 2013 Valeo Powertrain Forecast, D. Benchentrite, EEHE meeting, Bamberg, Germany, May 2014 In recent years, HEV with start/stop system has been developed rapidly. EFB and AGM batteries can be used in start/stop system. 7

8 Lead-acid battery technology comparison The above data show that the cold cranking, cycle life and deep discharge capacity of EFB are a bit lower than that of AGM battery. 8

9 2. Negative additives selection & trial 9

10 The 3 important components of negative additives are ligninsulfonate, carbon and barium sulfate Ligninsulfonate Influences the growth of spongy lead and lead sulfate crystallization Carbon Improves conductivity of lead sulfate and charge - discharge capacity Barium sulfate Provides nucleus for the formation of lead sulfate 10

11 Cell, Test standard Laboratory cell design Container size length/ mm width/ mm height/ mm Grid size length/ mm height/ mm thickness/ mm Active material/g Quantity Overall Core cavity Positive Negative Test standard JB/T (Chinese standard) equals to SBA S 0101:2014, EN , VDA AGM: Five cells per batch are made for every recipe. 11

12 2.1 Selection and test of ligninsulfonates 12

13 Lignin sulfonate as an important negative organic expander can significantly improve discharge performance at low temperature, but not good for charge acceptance. The solubility, particle size of ligninsulfonate in sulphuric acid solution and their effect on the charging and discharging properties of batteries have been studied in this work. The tentative additives contain ligninsulfonate %, carbon 0.25% and BaSO 4 1%. 13

14 Particle size of ligninsulfonates in sulphuric acid solution of 1.28g/cm³ varies with temperature. MALVERN particle size analyzer 14

15 Particle size of ligninsulfonates in sulphuric acid solution of 1.24 g/cm³ at different temperature a:5 b:25 c:50 Particle size of ligninsulfonates increases with the temperature. Different ligninsulfonates have different tendency of particle size change. 15

16 Solubility of different ligninsulfonates g/100g 25 THERMO UV spectrophotometer d,g/cm 3 There's a big difference in solubility of different ligninsulfonates in sulfuric acid solution 16

17 Effect of lignosulfonate on capacity of cells Ah Test method: 0.3A to 1.75V The most suitable additive amount is different for different lignosulfonates. 17

18 Ligninsulfonates effect on CCA, V 10s Cold 40A(8C) for 10s at -18 V Test method: 40A(8C) for 10s, -18 The discharge voltage,v 10s has big difference with the increase of additive amount for different ligninsulfonates. 18

19 Ligninsulfonates effect on CCA, V 30s Cold 40A(8C) for 30s at -18 V Test method: 40A for 30s at -18 The discharge voltage, V 30s has small difference with the increase of additive amount. 19

20 Ligninsulfonates effect on static charge acceptance A Static charge acceptance reduces with the increase of additive amount, but the reduction level is different for different ligninsulfonates. 20

21 Summary There are some relation between the particle size, solubility of ligninsulfonate and CCA, charge acceptance of battery. The most of ligninsulfonates improve low temperature performance. But the ligninsulfonates have a negative impact on charge acceptance, and the more dosage the worse charge acceptance. 21

22 2.2 Selection and test of carbon materials 22

23 Carbon as negative expander has a big impact on battery low temperature performance and charge acceptance We ve done the comparison tests of carbons having different surface area and particle size with additive of ligninsulfonate 0.2% and BaSO 4 1.0% 23

24 Effect of carbon on capacity of cell Ah Test method: 0.3A to 1.75V Different carbon materials have different optimal additive amount. 24

25 Carbon effect on CCA; V 10s, V 30s Voltage of cold 40A(8C) for 10s and 30s at -18 V Different carbon materials have different influence on CCA. 25

26 Carbon s effect on static charge acceptance A With the increase of carbon additive amount, the static charge acceptance improves. But the charge acceptance for some carbon might quickly reduces when the additive amount reaches a certain value. 26

27 Summary Different carbon materials have different optimal additive amount. Most of carbon has negative impact on CCA of batteries. Carbon improves charge acceptance. But if the surface area of carbon is too large, the charge acceptance might quickly reduces when the additive amount reaches a certain value. 27

28 2.3 Selection and test of barium sulfates 28

29 The function of barium sulfate is to work as the crystal nucleus of lead sulfate, preventing the plate shrink during the charging cycle and improving battery discharge and charge acceptance. Due to different process technologies, the particle size and distribution as well as structure of barium sulfates vary a lot, which will have different effects on battery performance. 29

30 The particle size distribution of barium sulfates Sample N Sample Y 30

31 SEM of BaSO 4 Ball morphology of sample N Enlarged image of the ball morphology 31

32 SEM of BaSO 4 Structure of sample A Enlarged image of sample A 32

33 Barium sulfate effect on CCA, V 10s, V 30s Voltage of cold 8C for 10s, 30s at -18 V Test method: 40A for 10s, 30s at

34 Barium sulfate effect on static charge acceptance A 34

35 Summary In a certain range, barium sulfate with small particle size can improve the cold cranking ability, but may reduce the charge acceptance. Similarly, the addition of barium sulfate can increase the cold cranking ability, but may reduce the charge acceptance. 35

36 3. Testing of cell with composite additive formula 36

37 Testing Cell Capacity:65Ah Plates:7 Positive, 6 Negative Separator:PE We assemble testing cell and make trials with different composite additive formulas. 37

38 Results of testing cells with different composite additive formulas Cell weight /g OCV /V Capacity 1 /Ah Capacity 2 /Ah Capacity 3 /Ah Internal resistance /mω 10s Voltage /V 30s Voltage /V SCA /A Control Formula Formula Formula Formula Formula Formula

39 Cold cranking voltage, V 10s, V 640A for 10s & 30s at -18 V 39

40 Static charge acceptance A 40

41 From the cell test results, we can see that CCA and charge acceptance have been significantly improved with some formulas, and then we assemble batteries and test them with the further optimization of the formula. 41

42 4. Testing of EFB with new composite additive formula 42

43 Test results of EFB (sample battery with new composite additive formula ) Battery A V T L Sample Type 12V65Ah 12V65Ah 12V60Ah 12V60Ah 12V60Ah Weight(kg) I.R.(mΩ) C 20 (Ah) A 10s Voltage(V) s Voltage(V) C 20 (Ah) A 10s Voltage(V) s Voltage(V) C 20 (Ah) Charge acceptance(a) DCA(As)

44 Voltage of cold cranking, V 10s, V 640A for 10s & 30s at -18 V 44

45 Charge acceptance A As Static charge acceptance Dynamic charge acceptance 45

46 Start-stop cycling ability testing V Cycles 46

47 17.5%DOD cycle life 47

48 5. Conclusion 48

49 Conclusion Through the study of additive s characteristic and its influence to battery performance, and a series of the cell and battery testing, we ve successfully developed a new generation of paste additive for EFB, which can significantly improve the CCA, charge acceptance and cycle life. We sincerely hope to work closely with battery producers for further improvement. 49

50 Thanks for your attention! Exhibition site of JINKELI, booth #64 http: