WO2011086562A1 - Procédé de chargement par impulsions - Google Patents

Procédé de chargement par impulsions Download PDF

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Publication number
WO2011086562A1
WO2011086562A1 PCT/IL2011/000053 IL2011000053W WO2011086562A1 WO 2011086562 A1 WO2011086562 A1 WO 2011086562A1 IL 2011000053 W IL2011000053 W IL 2011000053W WO 2011086562 A1 WO2011086562 A1 WO 2011086562A1
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WO
WIPO (PCT)
Prior art keywords
charging
pulse
battery
cell
battery cells
Prior art date
Application number
PCT/IL2011/000053
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English (en)
Inventor
Eran Ofek
Original Assignee
Eran Ofek
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eran Ofek filed Critical Eran Ofek
Publication of WO2011086562A1 publication Critical patent/WO2011086562A1/fr

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00711—Regulation of charging or discharging current or voltage with introduction of pulses during the charging process

Definitions

  • the present invention relates to a method of battery recharging, and, more specifically, it pertains to a method of pulse charging.
  • the high temperatures may also initiate unwanted or irreversible chemical reactions and/or loss of electrolyte which can cause permanent damage or complete failure of the battery. This in turn sets an upper temperature operating limit for the battery.
  • the electrolyte may freeze, setting a limit to low temperature performance. But well below the freezing point of the electrolyte, . battery performance starts to deteriorate as the rate of chemical reaction is reduced. Even though a battery may be specified to work down to -20°C or -30°C the performance at 0°C and below may be seriously impaired.
  • the lower temperature working limit of a battery may be dependent on its State of Charge.
  • Sulphuric Acid electrolyte becomes increasingly diluted with water and its freezing point increases accordingly.
  • the battery must be kept within a limited operating temperature range so that both charge capacity and cycle life can be optimized.
  • a practical system may therefore need both heating and cooling to keep it not just within the battery manufacturer's specified working limits, but within a more limited range to achieve optimal performance.
  • Nickel Metal Hydride (NiMH) cells are also exothermic during charging and as they approach full charge, and the cell temperature can rise dramatically. Consequently, chargers for NiMH cells must be designed to sense this temperature rise and cut off the charger to prevent damage to the cells.
  • Nickel based batteries with alkaline electrolytes (NiCads) and Lithium batteries are endothermic during charging. Nevertheless thermal runaway is still possible during charging with these batteries if they are subject to overcharging.
  • thermochemistry of Lithium cells is slightly more complex, depending on the state of intercalation of the Lithium ions into the crystal lattice.
  • the reaction is initially endothermic then moving to slightly exothermic during most of the charging cycle.
  • discharge the reaction is the reverse, initially exothermic then moving to slightly endothermic for most of the discharge cycle.
  • the Joule heating effect is greater than the thermochemical effect so long as the cells remain within their design limits.
  • the thermal condition of the battery is also dependent on its environment. If its temperature is above the ambient temperature it will lose heat through conduction, convection and radiation. If the ambient temperature is higher, the battery will gain heat from its surroundings. When the ambient temperature is very high the thermal management system has to work very hard to keep the temperature under control. A single cell may work very well at room temperature on its own, but if it is part of a battery pack surrounded by similar cells all generating heat, even if it is carrying the same load, it could well exceed its temperature limits.
  • thermo-electrical and thermo-chemical effects possibly augmented by the environmental conditions, is usually a rise in temperature and as noted above, this will cause an exponential increase in the rate at which a chemical reaction proceeds. It is also known that if the temperature rise is excessive the active chemicals expand causing the cell to swell. Subsequent problems include:
  • the temperature rise causes the chemical reaction to speed up increasing the temperature even more and could lead to thermal runaway
  • the cell may eventually rupture or explode
  • the thermal capacity of an object defines its ability to absorb heat. In simple terms for a given amount of heat, the bigger and heavier the object is, the smaller will be the temperature rise caused by the heat.
  • the operating temperature which is reached in a battery is the result of the ambient temperature augmented by the heat generated by the battery. If a battery is subject to excessive currents the possibility of thermal runaway arises resulting in catastrophic destruction of the battery. This occurs when the rate of heat generation within the battery exceeds its heat dissipation capacity. There are several conditions which can bring this about:
  • the thermal management system must keep all of these factors under control.
  • This thermal model is developed based on the pseudo two-dimensional (P2D) model and a thermal electrochemistry coupled model.
  • P2D pseudo two-dimensional
  • the diffusion coefficient of Li ions in the solid phase and electrolyte, the reaction rate constants of the electrochemical reactions, the open circuit potentials and the thermal conductivity of the binary electrolyte depend on the temperature in the model presented here.
  • h is the heat transfer coefficient
  • T ⁇ is the environmental temperature
  • Q rev is the total reversible heat generation rate
  • Q ohm is the total ohmic heat generation rate.
  • the temperature dependent open circuit potential of electrode is approximated by Taylor's first order expansion around a reference temperature:
  • a ID geometry which consists of three sequentially connected lines to represent the positive electrode, the separator and the negative electrode, respectively
  • a 2D geometry which consists of two rectangles to denote the solid phase in the electrodes are considered.
  • the considered geometries are shown in Fig. 1.
  • the vertical coordinate in the 2D geometry indicates the radial direction of the solid particles. Since we ignore the diffusion of Li ions in the x-direction in the particle, the corresponding diffusion coefficient is set to zero in this direction.
  • the concentration of the binary electrolyte, the potential in the electrolyte, the potential in the solid phase and the pore wall flux are solved in the ID geometry.
  • the concentration of Li ions in the solid phase is solved in the 2D geometry.
  • the pore wall flux is extruded from the ID domain and projected to the top boundary of the 2D geometry by using "subdomain extrusion coupling variables".
  • concentration of Li ions on the top boundary in the 2D geometry is projected to the ID domain by using "boundary extrusion coupling variables”.
  • the battery is discharged for 3000s at C/2 rate first and then discharged at 3C rate until the cell voltage drops to 2.5V.
  • the change of the applied current density is implemented by using the smoothed Heaviside function "flsmhs" and is shown in Fig. 2.
  • Fig. 3 shows the temperature on the cell surface at 1C discharge process under three different cooling conditions where the heat transfer coefficient is 10.0, 1.0 and 0.1 W/m2/K, respectively, and two limiting conditions: the isothermal condition and the adiabatic condition.
  • the thermal effect on the cell voltage is shown in Fig. 4.
  • the cell provides more discharge capacity when it is placed in a better heat isolation environment (i.e. adiabatic condition). In a better isolated environment, the cell temperature increases faster during the 1C discharge process which results in the higher diffusion coefficient for the binary electrolyte and reduces the diffusion limitations.
  • Fig. 5 shows the concentration profiles of the electrolyte at the end of 1C discharge process under the two limiting conditions.
  • the concentration profile under the adiabatic condition is flatter than that in the isothermal case, which indicates a better diffusion property in the electrolyte under the adiabatic condition than under the isothermal condition.
  • Fig. 6 shows the cell temperature during the 1C discharge process at different current rates as the heat transfer coefficient is 1.0 W/m2/K. As expected, the cell gets hotter as the discharge current rate increases. It is also noticed that the wave part which appears in beginning of the temperature curve at low current rate (less than 2C) does not exist in the high current rate cases. The wave part on the temperature curve is characterized by the reversible heat generation during discharging. Under low current rate discharging, the reversible heat is roughly equivalent to the ohmic heat, but becomes unimportant as the discharge current rate increases.
  • the P2D model mentioned in section 2 is also useful for simulating the discharge process with pulse. Fig.
  • Fig. 7 shows the cell voltage during the C/2 discharge for 3000s followed by a 3C pulse discharge until the cell voltage drops to 2.5V.
  • the corresponding temperature on the surface of the cell is also plotted in Fig. 8.
  • the surface temperature at the end of the 3C pulse is slightly less than that in the pure 3C discharge process.
  • Fig. 9 shows the concentration of the binary electrolyte at the two ends of the cell during the pulse discharge process. At the beginning of the pulse, the concentration of the electrolyte changes extremely, after that it relaxes and tend to a stable value.
  • US Patent 5945811 discloses a pulse charging method and charging system for use with non-aqueous secondary batteries, employing a pulse charge controlling method all the way from the start to the end of charging.
  • the pulse charging method has an on-duty ratio of pulses in a next specified charge period reduced when an average battery voltage has exceeded a charge control voltage during a specified charge period, has an on-duty ratio of pulses in a next specified charge period increased when the average battery voltage has not exceeded the charge control voltage and has the pulse charging ended when an on-duty ratio of pulses has reached a specified value.
  • the pulse charging system comprises an on-duty ratio reducing means for having an on-duty ratio of pulses reduced, an on-duty ratio increasing means for having an on-duty ratio increased and a means for determining pulse charge ending for having the pulse charging ended when an on-duty ratio of pulses has reached a specified value.
  • the aforesaid method comprises the steps of: (a) providing a charging device connectable to a source of electric energy; the charging device adapted for providing a voltage pulse train to the terminals; (b) electrically connecting the charging device to the terminals of battery cells; and (c) pulse charging the pack of battery cells by means of applying a train of the voltage pulse train to the terminals.
  • the step of pulse charging is performed by means of applying the train of voltage pulses over the battery cells in a cyclic consecutive manner.
  • Another object of the invention is to disclose a time interval between said charging pulses at said step of pulse charging which are applied to each cell is sufficient for dissipating heat generated by a charging current conducted across said cell.
  • a further object of the invention is to disclose the interval between the charging pulses comprising at least one voltage pulse of an opposite polarity.
  • a further object of the invention is to disclose the train of charging pulses comprising a plurality of sutbrains.
  • the charging pulses belonging to one subtrain are identically to each other.
  • the charging pulses belonging to one subtrain are consecutively distributed over said battery cells.
  • a further object of the invention is to disclose a duration of the charging pulse increasing over time of charging.
  • a further object of the invention is to disclose a duration of the pulse interval increases over time of charging.
  • a further object of the invention is to disclose a step of monitoring battery pack parameters and optimizing charging process.
  • a further object of the invention is to disclose a device for pulse charging of a pack of battery cells provided with battery terminals.
  • the aforesaid device is connectable to a source of electric energy.
  • the pulse charging device comprises a generator of a voltage pulse train provided to the terminals.
  • the commutating circuitry is adapted to commutate the voltage pulses over the battery cells in a cyclic consecutive manner.
  • Fig. 1 is a scheme presenting geometries and variables coupling between the geometries
  • Fig. 2 is a graph of current density profile in the discharge process including a 3C pulse
  • Fig. 3 is a graph of the temperature on the cell surface during 1C discharge process under different cooling conditions
  • Fig .4 is a graph of the cell Voltage for 1C discharge process under different cooling conditions
  • Fig. 5 is a graph of the concentration profiles of the binary electrolyte at the end of the 1C discharge process under the isothermal condition and the adiabatic condition;
  • Fig. 6 is a graph of the temperature on the cell surface during discharge process under different current rates
  • Fig. 7 is a graph of the cell Voltage at C/2 discharge for 3000s followed by a 3C pulse discharge
  • Fig. 8 is a graph of the temperature on the cell surface in the discharge process with 3C pulse
  • Fig. 9 is a graph of the concentration of the binary electrolyte at the two ends of the cell.
  • Fig. 10 is a block diagram of the pulse charging device connected to the battery pack
  • Fig. 1 1 is a graph of the train of the pulses applied to one battery cell
  • Fig. 12 is a graph of voltage on the battery cell which is charged by the pulse train
  • Fig. 13 is a graph of the train of the pulses applied to three battery cells
  • Fig. 14 a-c are a schematic presentation of cylindrical battery cell and a graph of the dependence of the form factor on cell quantity;
  • Fig. 15 a-c are a schematic presentation of brick battery cell and a graph of the dependence of the form factor on cell quantity;
  • Fig. 16 is a pseudo-color pattern of the temperature distribution over battery cell.
  • Fig. 17 is a pseudo-color pattern of the temperature distribution over multi-cell battery created in the course of the pulse charging process.
  • dQ sen /dt is generated energy per unit of time
  • dQ &ss ldt is dissipated energy per unit of time
  • flatt is specific-heat capacity of a battery.
  • Damage to weaker cells can also continue during the discharge cycle.
  • the capacity of the weakest cell in the chain will be depleted before the others. If the discharge is continued (to discharge the remaining good cells), the voltage on the low capacity cell will reach zero then reverse due to the IR voltage drop across the cell. Subsequent heat and pressure build up within the cell due to "cell reversal" can then cause catastrophic failure.
  • cyclically consecutively charging refers to consecutively charging battery cells of a battery pack.
  • the sequence of charging is a closed-loop cycle.
  • Fig. 10 shows a pulse charging device 100 electrically connected to a battery pack 150 comprising a plurality of battery cells 160.
  • the pulse charging device 100 is energized by a power source 110.
  • the pulse charging device comprises a pulse generator adapted to generate a train of voltage pulses characterized by variable pulse durations and intervals between pulses and a commutation circuitry 130 which distributes the pulses belonging to the generated train over the battery cells 160 is a consecutive cyclic manner.
  • Fig. 11 presenting a train of voltage pulses applied to one battery cell.
  • the pulses in the train are separated by time intervals which are sufficient for dissipation of heat generated by charging current.
  • cell charging is performed by the train of pulses of relatively short duration in comparison with the interval therebetween.
  • the aforesaid pulse train comprises a voltage pulse of opposite polarity.
  • Fig. 12 showing a time curve of voltage at the terminals of the battery cells in the process of charging.
  • the battery cell is provided with charging current.
  • the cell is charged in a continuous manner. Further, the cell is charged by the train of pulses of increasing relative pulse duration.
  • Fig. 13 illustrates the core of the present invention.
  • a train of voltage pulses is distributed over a group of three battery cells in a consecutive cyclic manner.
  • the charging process is organized in such a way that each battery cell is charged in a time period when the other two cells dissipate the heat generated by the charging current therein.
  • the proposed technical solution reduces likelihood of a battery fault because of thermal runaway. It is herein acknowledged that in some embodiments of the invention, any number of battery cells can constitute a chargeable pack.
  • Figs 14 a-c depicting dependence of heat dissipation on a form factor of a cylindrical battery.
  • FIG. 15a-c depicting dependence of heat dissipation on a form factor of a parallelepiped-like battery.
  • Fig. 16 presenting pseudo-color patterns characterizing temperature distribution over the battery body induced by charging/discharging current.
  • Fig. 17 showing pseudo-color patterns characterizing temperature distribution induced by charging/discharging current in the multi-cell battery.
  • the charging voltage pulses are applied to battery cells in a consecutive cyclic manner such that the interval between charging impulses applied to each battery cell is sufficient for dissipating the heat generated by the induced charging current.
  • a cell 5 is under action of charging pulse, while other cells 1-4 dissipated received heat and cool down.
  • the temperature distribution pattern of the battery cells corresponds to a charging protocol (cell sequence of charging). In this case cell of sequence 1-2-3-4-5, the cell 5 is the hottest one and cell 1 is coolest.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Secondary Cells (AREA)

Abstract

L'invention concerne un procédé de chargement par impulsions d'un bloc de cellules de batterie comportant des bornes de batterie. Plusieurs cellules de batterie sont disposées sous forme d'un bloc. Le procédé susmentionné comprend les étapes suivantes : (a) fournir un dispositif de chargement pouvant être connecté à une source d'énergie électrique; (b) connecter électriquement le dispositif de chargement aux bornes de la cellule de batterie; et (c) charger par impulsions le bloc de cellules de batterie en appliquant un train d'impulsions de tension aux bornes. L'étape de connexion électrique du dispositif de chargement aux bornes des cellules de batterie se fait individuellement pour chaque cellule. L'étape de chargement par impulsions se fait en appliquant le train d'impulsions de tension sur des groupes de cellules de batterie dans le bloc, ceci de manière cyclique et consécutive.
PCT/IL2011/000053 2010-01-18 2011-01-18 Procédé de chargement par impulsions WO2011086562A1 (fr)

Applications Claiming Priority (2)

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US29577910P 2010-01-18 2010-01-18
US61/295,779 2010-01-18

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WO2011086562A1 true WO2011086562A1 (fr) 2011-07-21

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109270460A (zh) * 2018-09-04 2019-01-25 南京工业大学 锂离子电池热失控的能量计算方法
WO2023017336A1 (fr) * 2021-08-12 2023-02-16 Tula eTechnology, Inc. Procédé d'optimisation d'efficacité de système pour moteurs électriques alimentés par batterie
US11888424B1 (en) 2022-07-18 2024-01-30 Tula eTechnology, Inc. Methods for improving rate of rise of torque in electric machines with stator current biasing

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US588938A (en) * 1897-08-31 Press
US5686815A (en) * 1991-02-14 1997-11-11 Chartec Laboratories A/S Method and apparatus for controlling the charging of a rechargeable battery to ensure that full charge is achieved without damaging the battery
US6124698A (en) * 1998-06-09 2000-09-26 Makita Corporation Battery charger
US6307352B1 (en) * 1999-10-19 2001-10-23 Enrev Corporation High energy charge and depolarization pulse conditioner for an enhanced-reliability lead-acid battery charger
US20050275381A1 (en) * 2004-06-09 2005-12-15 Guang Huang T Battery charger with dual use microprocessor
US20070212596A1 (en) * 1999-06-25 2007-09-13 Nebrigic Dragan D Single and multiple cell lithium ion battery with built-in controller
US20080272736A1 (en) * 2007-05-01 2008-11-06 Jenn-Yang Tien Smart lead acid battery (dis)charging management system
US20090289602A1 (en) * 2008-05-22 2009-11-26 Man Oi Ng Battery rejuvenation method and apparatus

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US588938A (en) * 1897-08-31 Press
US5686815A (en) * 1991-02-14 1997-11-11 Chartec Laboratories A/S Method and apparatus for controlling the charging of a rechargeable battery to ensure that full charge is achieved without damaging the battery
US6124698A (en) * 1998-06-09 2000-09-26 Makita Corporation Battery charger
US20070212596A1 (en) * 1999-06-25 2007-09-13 Nebrigic Dragan D Single and multiple cell lithium ion battery with built-in controller
US6307352B1 (en) * 1999-10-19 2001-10-23 Enrev Corporation High energy charge and depolarization pulse conditioner for an enhanced-reliability lead-acid battery charger
US20050275381A1 (en) * 2004-06-09 2005-12-15 Guang Huang T Battery charger with dual use microprocessor
US20080272736A1 (en) * 2007-05-01 2008-11-06 Jenn-Yang Tien Smart lead acid battery (dis)charging management system
US20090289602A1 (en) * 2008-05-22 2009-11-26 Man Oi Ng Battery rejuvenation method and apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109270460A (zh) * 2018-09-04 2019-01-25 南京工业大学 锂离子电池热失控的能量计算方法
CN109270460B (zh) * 2018-09-04 2021-08-24 南京工业大学 锂离子电池热失控的能量计算方法
WO2023017336A1 (fr) * 2021-08-12 2023-02-16 Tula eTechnology, Inc. Procédé d'optimisation d'efficacité de système pour moteurs électriques alimentés par batterie
US11673476B2 (en) 2021-08-12 2023-06-13 Tula eTechnology, Inc. Method of optimizing system efficiency for battery powered electric motors
US11888424B1 (en) 2022-07-18 2024-01-30 Tula eTechnology, Inc. Methods for improving rate of rise of torque in electric machines with stator current biasing

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