Coup De Fouet Research Articles

Predicting the state of health of VRLA batteries in UPS using data-driven method

Uninterruptible power battery (UPS) is an important part to ensure the stable operation of data center. Its security is related to the reliability and stability of power system. Among them, the state of health (SOH) prediction is a key issue of the valve regulated lead–acid (VRLA) battery operation and maintenance in data center. In this work, the battery SOH is predicted by the correlation between the nadir voltage value of Coup De Fouet (CDF) phenomenon and SOH. Then, the CDF phenomenon is combined with popular data-driven methods, such as linear regression, regression tree, support-vector machine, gaussian process, neural network, to predict battery SOH through 215 features. Finally, the above method is verified with the real discharge dataset of UPS battery in data center. The experimental results show that the data-driven method combining big data has higher accuracy than the simple prediction of battery SOH based on the nadir voltage value of CDF phenomenon and its variants.

Charge coup de fouet phenomenon in soluble lead redox flow battery

The charge coup de fouet phenomenon, known in the context of lead-acid battery, refers to the presence of a voltage dip shortly after charging of a fully discharged battery begins. While the attempts to relate magnitude of coup de fouet phenomena with the state of health of battery have appeared in the literature, the phenomena continue to be poorly understood. The soluble lead redox flow battery (SLRFB), with potential for energy storage at large scale at low cost, also displays similar features. We report in this work our modeling and experimental efforts aimed at understanding charge coup de fouet phenomenon in natural convection driven SLRFB. We present a model that incorporates the presence of non-conducting PbO in deposits through a percolation type model for conductivity. The associated potential drop across the deposits is incorporated in the model through reduced overpotential available for driving Butler–Volmer kinetics. The complete model with coupled natural convection induced by non-uniform concentration of Pb ions in electrolyte successfully captures charge coup de fouet phenomenon, and explains the measured variation of its magnitude with the depth of discharge in the previous cycle. The model explains our earlier observation that during the discharge process, a receding zone of deposits is seen only on cathode but not on anode. The approach used is applicable to electrochemical systems in which solid conducting matrix evolves to non-conducting or poorly conducting and vice-versa, with a change in composition.

VRLA Battery SOH Estimation Based on WCPSO-LVSVM

The correlation between operation parameters including coup de fouet and SOH was analyzed to choose the input parameters of the battery SOH estimation model, and then the battery SOH estimation model was made based on least square support vector machine (LSSVM). For more prediction accuracy and efficiency, the advanced particle swarm optimization (WCPSO) is used to optimize the parameters of the LS-SVM regression model. The battery SOH was estimated only with measured data (plateau voltage, discharge rate and temperature) of short time discharge, so it is efficient. The verification result shows that the WCPSO-LSSVM model can be used to predict the battery SOH, and the precision is above 93%.

State-of-health estimator based-on extension theory with a learning mechanism for lead-acid batteries

The main objective of this paper is to design and implement an improved intelligent state-of-health (SOH) estimator for estimating the useful life of lead-acid batteries. Laboratory studies were carried out to measure and record the distributed range of characteristic values in each SOH cycle for the battery subject to cycles of charging and discharging experiments. The measured coup de fouet voltage, internal resistance, and transient current are used as characteristics to develop an intelligent SOH evaluation algorithm. This method is based on the extension matter-element model that has been modified in this research by adding a learning mechanism for evaluation SOH of batteries. The proposed algorithm is relatively simple so that it can be easily implemented with a programmable system-on-chip (PSOC) microcontroller achieve rapid evaluation of battery SOH with precision by using a concise hardware circuit.

Isolated Rupture of the Plantaris Tendon in a High School Track Athlete

P lantaris muscle or tendon injuries, although rare, have been discussed for over a century. The plantaris is a rudimentary muscle located in the superficial posterior compartment of the leg and varies in its size and development. It originates at the inferior aspect of the lateral supracondylar line of the femur and consists of a small fusiform fleshy muscle belly with a long, slender tendon that crosses obliquely between the gastrocnemius and soleus before inserting into the medial posterior calcaneus, sometimes via the Achilles tendon or occasionally fusing with the flexor retinaculum or leg fascia. Reports of isolated ruptures of the plantaris muscle or tendon are rare, but this is probably related more to misdiagnosis as Achilles tendon pathology, and that they heal quickly, than the paucity of the injury. Plantaris tendon ruptures rarely are isolated, often involving the gastrocnemius or the Achilles tendon. The term coup de fouet, or snap of the whip, was coined in 1597 to describe an Achilles tendon rupture; some authors have used the term, inappropriately, to describe plantaris tendon ruptures. Tennis leg was used to describe plantaris tendon and muscle ruptures, causing more confusion and debate. Few cases of isolated plantaris tendon rupture have been reported. These ruptures occurred at the insertion on the calcaneus or at the proximal musculotendinous junction. To our knowledge, no case has been reported regarding the rupture of the mid-plantaris tendon in isolation, making our patient’s case unique. CASE REPORT A 16-year-old male high school track athlete (6’3’’, 158 lbs) presented to the office complaining of pain in the right Achilles tendon region. He was in his mid-season training, performing modest speed work twice weekly coupled with distance running of roughly 30–40 miles weekly; he performed no plyometric training. On the previous day (weather was sunny, approximately 501F), while performing an afternoon speed workout, he was nearing the end of his fourth 200-meter sprint and felt a ‘‘pop’’ in his right posterior lower-leg region, causing him to fall. He was able to walk, stiffly, afterwards, but incurred mild swelling and pain that evening. The patient denied numbness, tingling, weakness, joint pain, and previous injuries and was otherwise in excellent health, with no allergies and no present or recent medication or supplement use. Standing exam revealed normal foot structure. Strong, equal pulses were palpated bilaterally at his distal lower extremities and capillary refill was less than 2 seconds. No motor or sensory deficits were identified, and excellent plantar

Study of the “coup de fouet” of lead-acid cells as a function of their state-of-charge and state-of-health

This paper shows some new results concerning the influence of operating conditions on the phenomenon known as “coup de fouet”, a voltage drop which occurs at the beginning of the discharge of lead-acid batteries (LABs) previously fully charged. Even if this phenomenon is often suggested for diagnosing the state-of-charge (SOC) and the state-of-health (SOH) of LABs, it remains badly understood. Furthermore, this study deals with other transient voltage responses of LABs to galvanostatic polarisations that depend on their SOC, either on discharge or on charge. A special attention is paid to a phenomenon occurring at the beginning of the charge of these batteries after a full discharge, and which can be compared to the “coup de fouet” on many aspects. Without giving a final answer concerning the origin of these two phenomena, our results present some contradictions with the explanation generally accepted today. It is, also, shown that the study of these phenomena constitutes an original means to investigate the full-charge and full-discharge conditions, together with other characterization methods like impedance spectroscopy. On the other hand, results presented show that it is not possible to connect the “coup de fouet” parameters to the battery capacity without taking care of the high-SOC level, the rest time preceding the discharge, and the depth of the latter discharge, which compromises the reliability of this method suggested in several papers and patents, in particular in applications with irregular cyclings.

Standby Power System VRLA Battery Reserve Life Estimation Scheme

This paper presents a valve-regulated lead acid (VRLA) battery reserve life estimation scheme. The scheme is adaptive in both type and frequency of involvement. The scheme is based on capacity trending with the support of a number of state-of-health (SOH) indicators. These SOH indicators include accumulated thermal stress, float voltage, and indicators acquired from the start-of-discharge (coup de fouet) region. An implementation test case is given, indicating that the scheme is capable of providing an accurate estimation of reserve life long before the end of life. Furthermore, the estimation accuracy improves as the end of battery life approaches.

04/02795 Control-oriented nonlinear modelling of moltencarbonate fuel cells: Shen, C. et al. International Journal of Energy Research, 2004, 28, (5), 403–410

This paper presents the results of an investigation into the initial stage of the discharge voltage response of valve-regulated lead–acid (VRLA) batteries. This region is dominated by the phenomenon known as the coup de fouet which manifests itself as a voltage dip followed by a recovery. The research focuses on two parameters found within the coup de fouet region, namely, the trough and the plateau voltage. It is found that these parameters are influenced by the operating conditions and the sate-state-of health (SoH) of the battery. The operating conditions considered are discharge rate, ambient temperature, depth of previous discharge, charge duration, and float voltage. The coup de fouet parameters corresponding to high rate discharges, as well as discharges conducted at low temperatures, have reduced magnitudes compared with those conducted at lower rates or higher temperatures. This behaviour mirrors the availability of capacity when the battery is discharged under the same operating conditions. The float voltage is found to have a direct relationship with the trough and plateau voltages, whereas an indirect relationship between charge duration and the trough and plateau voltages is observed. The influence of variations in discharge depth on the coup de fouet is more complex. For consecutive discharge depths below approximately 10% of rated capacity, the coup de fouet becomes distorted and exhibits a second voltage dip. For consecutive discharges of greater depth, this does not occur. The influence of the degradation in battery SoH due to accelerated thermal ageing, water replenishment post-accelerated thermal ageing, and field ageing is investigated. The coup de fouet parameters associated with the discharge of batteries with low SoH have a reduced magnitude compared with those associated with the discharge of batteries with a high SoH.

Early stages of the lead-acid battery discharge

New electrochemical investigations of the Pb/PbO2/PbSO4 electrode are reported. In this study we focus on two related phenomena: an anodic peak that appears on cathodic sweep, which we regard as a reactivation peak and a voltage dip that appears in galvanostatic discharges, commonly known as “coup de fouet”. It was possible to demonstrate that the commonly accepted interpretation for the “coup de fouet” as PbSO4 nucleation over PbO2 surface is incorrect. From the comparison between galvanostatic and voltammetric experiments, the connection between the “coup de fouet” and the reactivation peak is elucidated and a model that explains the overall behavior is proposed.

A VRLA battery simulation model

A valve regulated lead acid (VRLA) battery simulation model is an invaluable tool for the standby power system engineer. The obvious use for such a model is to allow the assessment of battery performance. This may involve determining the influence of cells suffering from state of health (SOH) degradation on the performance of the entire string, or the running of test scenarios to ascertain the most suitable battery size for the application. In addition, it enables the engineer to assess the performance of the overall power system. This includes, for example, running test scenarios to determine the benefits of various load shedding schemes. It also allows the assessment of other power system components, either for determining their requirements and/or vulnerabilities. Finally, a VRLA battery simulation model is vital as a stand alone tool for educational purposes. Despite the fundamentals of the VRLA battery having been established for over 100 years, its operating behaviour is often poorly understood. An accurate simulation model enables the engineer to gain a better understanding of VRLA battery behaviour. A system level multipurpose VRLA battery simulation model is presented. It allows an arbitrary battery (capacity, SOH, number of cells and number of strings) to be simulated under arbitrary operating conditions (discharge rate, ambient temperature, end voltage, charge rate and initial state of charge). The model accurately reflects the VRLA battery discharge and recharge behaviour. This includes the complex start of discharge region known as the coup de fouet.

The behaviour of the coup de fouet of valve-regulated lead–acid batteries

This paper presents the results of an investigation into the initial stage of the discharge voltage response of valve-regulated lead–acid (VRLA) batteries. This region is dominated by the phenomenon known as the coup de fouet which manifests itself as a voltage dip followed by a recovery. The research focuses on two parameters found within the coup de fouet region, namely, the trough and the plateau voltage. It is found that these parameters are influenced by the operating conditions and the sate-state-of health (SoH) of the battery. The operating conditions considered are discharge rate, ambient temperature, depth of previous discharge, charge duration, and float voltage. The coup de fouet parameters corresponding to high rate discharges, as well as discharges conducted at low temperatures, have reduced magnitudes compared with those conducted at lower rates or higher temperatures. This behaviour mirrors the availability of capacity when the battery is discharged under the same operating conditions. The float voltage is found to have a direct relationship with the trough and plateau voltages, whereas an indirect relationship between charge duration and the trough and plateau voltages is observed. The influence of variations in discharge depth on the coup de fouet is more complex. For consecutive discharge depths below approximately 10% of rated capacity, the coup de fouet becomes distorted and exhibits a second voltage dip. For consecutive discharges of greater depth, this does not occur. The influence of the degradation in battery SoH due to accelerated thermal ageing, water replenishment post-accelerated thermal ageing, and field ageing is investigated. The coup de fouet parameters associated with the discharge of batteries with low SoH have a reduced magnitude compared with those associated with the discharge of batteries with a high SoH.

The syndrome of the "coup de fouet". Is it always a benign disease?

The "coup de fouet" syndrome is an uncommon condition characterized by a spontaneous intramuscular venous hemorrhage of the calf, sometimes accompanied by a deep thrombosis of the leg. The purpose of this work is to verify the real incidence of the thrombotic complications, making use of the most recent noninvasive diagnostic instruments, such as the duplex scanner and color Doppler. From January 1992 to December 1993, we examined 24 subjects (average age, 38.5 years) suffering from the so-called "coup de fouet" syndrome, which had appeared during physical activity: walking (nine cases), running (six cases), and sudden changes of position (nine cases). In all cases we performed a clinical and instrumental examination (analogical and tensive arterial and venous Doppler, arterial and venous duplex scanner, and color Doppler). Clinically we found, in 17 subjects, a hematoma in the posterior calf with increased thickness and, in 10 cases, with spontaneous sharp pain. In the other seven cases we found a modest hematoma without subjective or other objective symptoms. The arterial Doppler and scanner findings were normal. In the first group of 17 cases, the average clinostatic Doppler venous pressure, measured using a method developed by us and already described, was 32 +/- 4 mm Hg (normal value, 15 +/- 7 mm Hg); in the other seven cases the value was 19 +/- 4 mm Hg. The duplex scanner and color Doppler examination confirmed in all subjects the presence of an intrafascial hematoma in the gemellar zone; in 10 cases (41.7%), with more painful symptomatology, in a zone contiguous to the hemorrhage, we found a gemellar (six cases) or popliteal (four cases) phlebothrombosis. Lastly, we must point out that the syndrome is not always benign and that, therefore, a correct and more vigilant diagnostic and therapeutic approach is necessary.

Nucleation of Lead Sulfate in Porous Lead‐Dioxide Electrodes

A one‐dimensional mathematical model of a porous lead‐dioxide electrode is described and used to investigate lead‐sulfate nucleation and growth during discharge. Derivation of a nucleation rate expression that is based on classical, heterogeneous nucleation theory is outlined. An electrochemical kinetic expression is derived based on a reaction mechanism involving elementary steps, and concentrated ternary electrolyte theory is used in formulating material‐transport equations. Nucleation and electrochemical kinetic parameters are estimated by comparison of model results with experimental results available in the literature. The interplay of nucleation and growth kinetics of lead sulfate is responsible for the initial minimum in the voltage‐time curve that is commonly observed during constant‐current discharge. The model simulates the voltage minimum, which is referred to as the coup de fouet, and calculates the degree of lead‐ion supersaturation, the number density of lead‐sulfate particles, and the free energy of formation as well as the size of critical nuclei. The model also predicts a disappearance of the voltage minimum with the addition of seed particles for lead‐sulfate nucleation, which is experimentally observed. The satisfactory agreement between model and experimental results confirms that the voltage dip is caused by a temporary oversaturation of lead ions during discharge and supports the proposed theoretical approach.

The formation of soluble Pb(IV) and Pb(II) species in the reactions of the PbSO 4/PbO 2 electrode

Using a rotating gold ring—lead disc electrode and analysing the deposit on the ring surface with X-ray photoelectron spectroscopy, soluble Pb(IV) species were detected during the anodic reaction of the PbSO 4/PbO 2 electrode in sulfuric acid. The Pb(IV) species are not intermediates in the PbO 2 formation but result from the chemical solubility of PbO 2. Measurements of soluble Pb(II) proved that the “coup de fouet” commonly observed during the discharge of the lead acid battery is due to the oversaturation of Pb(II) ions.

A syndrome that is already a syndrome. "Coup de fouet" is "tennis leg".

A syndrome that is already a syndrome. "Coup de fouet" is "tennis leg".

THE "COUP DE FOUET" SYNDROME OF LOWER EXTREMITIES.

THE "COUP DE FOUET" SYNDROME OF LOWER EXTREMITIES.