Application of DSA-type electrodes to a positive grid in lead-acid batteries

The possibility of the use of modified DSA-type electrodes as positive grids in lead-acid batteries was examined by anodic polarization measurements, charge-discharge tests and self-discharge tests of the Ti/RuO₂ and Ti/RuO₂/-PbO₂ electrodes. The passivation of a titanium base was retarded by using a very thin film of ruthenium dioxide. The Ti/RuO₂/-PbO₂ electrode could be used as a positive grid to a certain extent. On the other hand, the Ti/RuO₂ electrode showed the worse characteristics for the positive grid, mainly due to the low oxygen overvoltage of the ruthenium dioxide layer. Some other problems to be solved have also been pointed out.     

Thermal runaway of valve-regulated lead-acid batteries

Valve-regulated lead-acid (VRLA) batteries that have aged on a float charge at constant voltage occasionally suffer from thermal runaway. Operating conditions for a VRLA battery have been simulated by changing the electrolyte saturation level in the separator and the ambient temperature. The charge current, battery temperature and cell overpressure were measured during current-limited constant-voltage charging. The experiments show that applied voltage, saturation level and ambient temperature are significant variables in the oxygen cycle. However, the saturation level of the electrolyte in the separator pore volume is critical. When it is lower than 80%, thermal runaway occurs readily. Significant corrosion of the positive grid and poor conductivity between the grid and the active mass (AM) is also found in aged VRLA batteries, and many inactive PbSO₄ crystals appear on the negative plates. As a result, both positive and negative plates have a very high resistance, which can accelerate thermal runaway.     

Predicted and observed initial short circuit current for lead-acid batteries

Initial short circuit currents have been observed using our electronic short circuit switch and also predicted from terminal voltage and ohmic resistance according to Ohm's law for several kinds of lead-acid batteries in various states-of-charge. Ohmic resistance was measured by the d.c. step and the a.c. impedance methods. The predicted and the observed values have been compared in order to establish a prediction method for initial short circuit current. A good agreement was obtained, the root mean square percentage deviation of the predicted value from that observed being only 219%, which confirms the validity of the prediction method for the initial short circuit current.     

Comparative study of lead-acid batteries for photovoltaic stand-alone lighting systems

The lead-acid battery is often the weakest link in photovoltaic (PV) installations. Accordingly, various versions of lead-acid batteries, namely flooded, gelled, absorbent glass-mat and hybrid, have been assembled and performance tested for a PV stand-alone lighting system. The study suggests the hybrid VRLA batteries, which exhibit both the high power density of absorbent glass-mat design and the improved thermal properties of the gel design, to be appropriate for such an application. Among the VRLA-type batteries studied here water loss for the hybrid VRLA batteries is minimal and charge-acceptance during the service at high temperatures is better in relation to their AGM counterparts.     

优化铅酸电池管式正极制备工艺参数的研究

为提高铅酸电池管式正极容量和寿命,设定不同的浸酸浓度和固化温度,通过混料、灌粉、浸酸、固化、化成工艺制备了一系列铅酸电池管式正极,并与容量过剩的负极板组装成小电池,考察了关键工艺条件浸酸酸度和固化温度对生极板中四碱式硫酸铅（4BS）含量、形态及对熟极板容量和寿命等性能的影响,借助XRD和SEM从微观层面分析了原因。结果表明,过高或过低的酸度和固化温度都不利于提高铅酸电池正极容量和寿命,最终确定了铅酸电池管式正极容量和寿命综合性能最佳的浸渍硫酸密度为1.1 g/cm³,固化温度为60 ℃。     

Metal-oxidized graphite composite electrodes for lithium-ion batteries

The electrochemical behavior of composite electrodes obtained by mixing graphite (Timrex KS-15 by Timcall), partially oxidized by thermal treatment, with nanometric metal particles (Au, Ag, Ni, Cu, Al, Sn) at about 1% (w/o) is presented. The charge-discharge properties of the composite electrodes have been studied in the temperature range 20 to −30 °C in 1 M LiPF₆ EC-DEC-DMC (1:1:1). The main effect is a general improvement of the cycling behavior at any temperature. In particular, at −30 °C about 30% of the theoretical intercalation capacity is retained by electrodes containing Cu, Al and Sn. At the same temperature, the composites containing the above metals show evidences of lithium staging. This may indicate that certain metals affect the kinetics of phase transformation that, together with other effects including charge transfer resistance, lithium diffusion coefficient and polarization due to SEI and solvent conductivities, seems to be the main cause of the poor intercalation capacity of graphite anodes at low temperature.     

Influence of superimposed alternating current on capacity and cycle life for lead-acid batteries

Capacity and cycle life have been measured for commercially available lead-acid batteries by superimposing an a.c. upon the charge and discharge d.c. to clarify the influence of an a.c. invasion into the d.c. system on battery performance in an electric power storage system. The current was controlled to beI=I ₀(1+sint) in all the experiments. The value ofI ₀ corresponded to 5 or 8 HR and the frequency range was 0.1 to 4000 Hz. No capacity change was observed for the a.c. superimposition on the charge current in this frequency range. When an a.c. was superimposed upon the discharge current the capacity of the battery increased by less than 1%. No effect on the cycle life caused by the a.c. superimposition on the charge and the discharge current was observed, as the inherent distribution of the cycle life of the batteries used was much greater than the change caused by the a.c. superimposition. Thus, it was clarified that the influence of the a.c. superimposition on battery capacity and cycle life is practically negligible for lead-acid batteries.     

A novel cureless pure lead oxide plate for valve-regulated lead-acid batteries

Pure lead oxide has been tested as a starting material for VRLA lead-acid batteries. The influence of the acid- to-oxide ratio and the paste density on the plate formation and battery performance has been investigated. The results show that the plates can be directly formed without undergoing the conventional plate curing process if pure lead oxide is used. The new process shows significant advantages in simplifying the conventional plate making processes for lead acid batteries and reducing the production cost and time.     

废铅酸蓄电池铅膏回收利用技术研究进展

总结了废铅酸蓄电池铅膏资源化利用技术的发展现状。重点介绍了废铅膏固相电解法回收铅工艺和废铅膏直接制备氧化铅的工艺。指出了经典火法工艺和湿法工艺未来的发展方向应主要集中于绿色环保和降低能耗等方面;同时废铅膏的固相电解法也为湿法技术的发展提供了一个值得关注的方向;废铅膏直接制备氧化铅的工艺现阶段还处于实验室水平,但是发展潜力很大,是未来铅膏回收领域的主流方向,应集中克服该工艺的低经济性和提高氧化铅纯度等问题。     

废铅酸蓄电池铅膏回收利用技术研究进展

总结了废铅酸蓄电池铅膏资源化利用技术的发展现状。重点介绍了废铅膏固相电解法回收铅工艺和废铅膏直接制备氧化铅的工艺。指出了经典火法工艺和湿法工艺未来的发展方向应主要集中于绿色环保和降低能耗等方面;同时废铅膏的固相电解法也为湿法技术的发展提供了一个值得关注的方向;废铅膏直接制备氧化铅的工艺现阶段还处于实验室水平,但是发展潜力很大,是未来铅膏回收领域的主流方向,应集中克服该工艺的低经济性和提高氧化铅纯度等问题。     

Theory of porous electrodes—XIV the lead-acid cell

Based on the theory of the positive and negative plates of the lead-acid battery, a system of six partial differential equations and one integral equation was derived describing the behaviour of the complete cell. The theoretical discharge behaviour of the plates either separately or in a cell was compared. The theoretical discharge capacity of a lead-acid cell at normal temperature and discharge rates is limited by the positive plate. The theory shows that a certain optimum plate distance exists at which the cell capacity is highest.     

Ideally rechargeable cadmium electrodes for alkaline storage batteries

Cd/Cd(OH)₂ electrodes based on sintered nickel substrate have been developed which show a stabilized capacity-utilisation of 96±2% pf the theoretical value even at the end of fifty cycles of deep discharge at ambient temperatures. Simultaneously, the extent of cadmium migration into the separator on extended cycling or storage has been found to be practically negligible. These improvements have been realized by the incorporation of an alkali-stable colloidal surfactant into the electrode during its fabrication so that both the crystal growth and migration of cadmium hydroxide are suppressed by a protective-colloid action of the surfactant.     

湿法回收废旧铅酸蓄电池中铅的研究进展

随着铅资源的日益枯竭,铅回收技术引来了人们广泛的研究。与传统的火法处理废旧铅蓄电池的技术相比,湿法处理技术作为一类环境友好型方法备受关注。本文阐述了各种湿法处理废旧铅蓄电池的工艺,并进行了评述。最后对我国未来铅回收工艺进行了展望。     

On the characterization of oxygen recombination in sealed lead-acid batteries

For characterizing the oxygen cycle in sealed lead-acid batteries the technological terms oxygen recombination efficiency and oxygen recombination conditions are introduced and their different meanings explained. Numerical values are calculated or estimated from plots of overpressure against time. Emphasis is placed on investigations of the influence of technological parameters on oxygen recombination conditions.Nomenclature F Faraday constant - D diffusion coefficient - L solubility coefficient - A effective surface area on the negative electrode covered with an electrolyte film - diffusion layer thickness - p _{O 2} oxygen partial pressure - p _{H 2} hydrogen partial pressure - I _OC overcharging current (defined negative) - I _{O 2red} oxygen reduction current - I _{H 2ev} hydrogen evolution current - I _{PhSO 4red} cathodic formation (recharge) current - P _{O 2}(St) steady-state P_{O 2} - p _{O 2} quasi steady-state p_{O 2} - R gas constant - T temperature - V gas space volume - (I_OC–I_{O 2red}–I_{H 2ev}) - viscosity - d electrode distance - l crack length - p electrolyte density     

Development of gel-polymer electrolytes and nano-structured electrodes for Li-ion polymer batteries

A novel methacrylic gel-polymer membrane was synthesized by free radical photo polymerisation (UV-curing technique). The polymerisation was very easy, fast and reliable and the membrane shows good behaviour in terms of both conductivity and cyclability in Li cells. The anode materials were prepared by high energy ball milling obtaining nanocrystalline Ni–Sn alloys, while the hydrothermal processing in presence of a template was used to prepare nanostructured LiFePO₄/C as cathode material. Every component has been characterised separately from the structural and electrochemical point of view. The first experimental data on the performance of a complete Li-ion polymer cell assembled with the components studied are also presented. The results obtained demonstrate the overall satisfying, and some superior performances of the various single components and their feasibility as a complete system.     

A modelling approach to the optimizaton of lead-acid battery electrodes

A resistive grid model was used to study the current and ohmic overpotential distributions along the surface of lead-acid battery electrodes. Analyses were made under two different regimes: the initial behaviour at high current densities and the response with time at low current densities. At high discharge currents the theoretical results show that the geometry of the electrodes and the position of the lug play the most important role in controlling the magnitude of ohmic losses. The best geometry is a square grid with the lug positioned at the upper centre of the electrode. At low discharge currents the model was used to follow the current distribution along the electrode surface as a function of time. In this last study the appearance, for long discharge times, of short-circuited concentration microcells localized in certain regions of the electrode surface was noted. The other regions of the electrode supply the external discharge current and the excess current necessary to charge the internal microcell.     

Effects of electrolyte stratification on performances of AGM valve-regulated lead-acid batteries

Two absorptive glass mat (AGM) valve-regulated lead-acid batteries with concentration and saturation stratification were simulated. Results indicate that the concentration stratification makes the active mass (AM) in lower part discharge deeply, which results in more irreversible sulphate on the negative plate because of inefficient recharge. In saturation stratification, more AM is also discharged in lower part, but the high oxygen recombination and undercharge in the upper part of the negative plate also leads to its sulphation. When the battery is in short-time rest state, the self-charge process occurs in the upper part and self-discharge process in the lower part of the same plate, but the processes differs with rest continuing. All these make the negative plate sulphation.