Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
  • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
  • B60L3/0046—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to electric energy storage systems, e.g. batteries or capacitors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
  • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
  • B60L58/12—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries responding to state of charge [SoC]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/44—Methods for charging or discharging
  • H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/46—Accumulators structurally combined with charging apparatus
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
  • H01M10/482—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for several batteries or cells simultaneously or sequentially
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/50—Current conducting connections for cells or batteries
  • H01M50/502—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing
  • H01M50/509—Interconnectors for connecting terminals of adjacent batteries; Interconnectors for connecting cells outside a battery casing characterised by the type of connection, e.g. mixed connections
  • H01M50/51—Connection only in series
• • 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
  • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
  • H02J7/0014—Circuits for equalisation of charge between batteries
  • H02J7/0016—Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
• • 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
  • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
  • H02J7/0014—Circuits for equalisation of charge between batteries
  • H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
• • 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
  • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
  • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
  • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
  • H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2220/00—Batteries for particular applications
  • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• • 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
  • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
  • H02J7/00302—Overcharge protection
• • 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
  • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
  • H02J7/00304—Overcurrent protection
• • 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
  • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
  • H02J7/00308—Overvoltage protection
• • 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
  • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
  • H02J7/00309—Overheat or overtemperature protection
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/60—Other road transportation technologies with climate change mitigation effect
  • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Definitions

• the invention relates to electrochemical storage battery modules, for example used in the field of electric and hybrid transport or embedded systems.
• the invention also relates to a method of balancing such a battery pack module.
• the invention can also be applied to supercapacitors.
• Hybrid combustion / electric or electric vehicles include in particular high power batteries used to drive an AC electric motor via an inverter.
• the voltage levels required for such engines reach several hundred volts, typically of the order of 400 volts.
• Such batteries also have a high storage capacity to promote the autonomy of the vehicle in electric mode.
• the electrochemical accumulators used for such vehicles are generally of the lithium-ion type for their ability to store significant energy with a weight and volume contained.
• LiFePO4 lithium iron ion-phosphate battery technologies are undergoing significant development due to a high intrinsic safety level, compared to conventional lithium-ion batteries based on cobalt oxide. .
• such a battery module Bat comprises several accumulator stages, for example four stages Eti, Et 2 , Et 3 and Et 4 , connected in series.
• Each stage comprises for example at least two, for example four, generally similar accumulators, connected in parallel.
• the voltage across the four stages is denoted respectively U1, U2, U3 and
• the total voltage U between the terminals N and P of the battery module 1 is the sum of the voltages U1, U2, U3 and U4.
• the current flowing through each accumulator of the fourth stage Et4 is noted respectively II, 12, 13 and 14.
• the current I generated on the terminal P of the battery module Bat is the sum of currents II, 12, 13 and 14.
• a charged accumulator results in a growth of the voltage at its terminals.
• a charged accumulator is considered when it has reached a voltage level defined by the electrochemical process.
• the lithium-ion type accumulators have a minimum voltage below which it is not necessary to go down so as not to degrade the accumulator.
• the paralleling accumulator branches comprising accumulators put in series, lithium-ion type does not naturally stop, are not used because it must be associated with each accumulator a clipping function and that you have to control the load of these.
• the large number of such circuits results in a high cost and a high impact on the bulk.
• One solution consists in using battery modules comprising series of accumulator stages comprising accumulators placed in parallel, as in the example of FIG. 1.
• a fault on an accumulator usually results in either short-circuiting the accumulator, either by an open circuit or by a large leakage current in the accumulator. It is important to know the impact of battery failure on the battery module. Open or short-circuiting may cause an overall failure of the entire battery module.
• the battery module behaves like a resistor which causes a discharge of the accumulators of the stage considered to zero.
• the risks of starting fire are low because the energy is dissipated relatively slowly.
• the discharge of the accumulators of the stage up to a zero voltage deteriorates them, which implies their replacement in addition to the initially defective accumulator.
• the fuse placed in series with the battery in short circuit will interrupt the parasitic discharge of the other three accumulators.
• each battery has a fuse connected to it in series.
• Fuse protection works on the principle of melting a metal conductor through which an electric current flows. When an accumulator forms a short circuit, the current flowing therethrough increases substantially and fuses its fuse in series to protect the rest of the battery pack Bat.
• the battery module comprises at least first and second branches each having at least first and second accumulators connected in series.
• the battery module further comprises a fuse via which the first accumulators of the branches are connected in parallel and through which the second accumulators of the branches are also connected in parallel.
• the cut-off threshold of the fuse is sized to open when one of the accumulators is short-circuited.
• some fuses can be crossed by the accumulation of charging or balancing currents to several accumulators of the same floor and remote charging connectivity. Some fuses may thus represent a common connection of several accumulators to the balancing circuit. Therefore, the dimensioning of the fuses of the parallel connections may be difficult to ensure both the protection of the accumulators, the continuity of service of the battery module during a malfunction of an accumulator, and the charging of different accumulators .
• the life of the fuses can also be reduced by the repeated application of load currents passing through them.
• the invention aims to at least partially solve these disadvantages of the prior art.
• the subject of the invention is a security system for a battery module, said system comprising:
• At least one battery module having a positive pole and a negative pole and defined by a matrix having a first predefined number n of columns, n being greater than or equal to two, and a second predefined number m of lines, m being greater than or equal to two, the matrix being such that:
• Each column defines a battery branch having accumulators in series, the accumulator branches being connected at their ends in parallel and to the poles of the battery module, and such that
• Each line of the matrix defines an accumulator stage, and at least one charge control device connected to the poles of the battery module,
• the battery module further comprises:
• a plurality of resistors respectively electrically connected to the intermediate point between two accumulators of two adjacent accumulator stages and
• the load control device is connected to all the connection nodes.
• the rows of resistors thus make it possible to connect each accumulator stage to a connection node common to all the n resistors of a row of resistors.
• the voltage measurement at a common node with n resistors provides information on the average voltage of a stage. Indeed, there is no paralleling of the accumulators so that the accumulator voltages of the same given floor are slightly different.
• the load control device connected to all the connection nodes can thus monitor the state of charge of all the accumulator stages by tracking their average voltage to the connection nodes. Only one load control device is required for all battery stages.
• This invention thus has the effect of benefiting from the safety of paralleling accumulators in series and the simplicity of balancing systems and monitoring of voltages.
• the resistors are simple components making it possible to limit the short-circuit current during a fault of an accumulator. In this way, a higher security is obtained in a simple manner at a lower cost than the solutions of the prior art with fuses for example.
• said resistors are identical. With identical resistors connecting each accumulator stage to a connection node, the voltage measured at the connection node necessarily corresponds to the average voltage of the accumulator stage.
• the accumulators are lithium iron ion-LiFePO4 type. Accumulators according to LiFeP04 technology generally having an end of charge voltage of the order of 3.6V can withstand an overvoltage before reaching the destruction voltage of the order of 4.5V. Such overvoltage may in particular occur in the event of malfunction with a short-circuited battery.
• the load control device comprises at least one balancing circuit electrically connected to all the connection nodes.
• the balancing circuit connected to the connection nodes can therefore monitor the state of charge of each accumulator stage and control the balance progressively for example as soon as a stage reaches the plateau voltage added to a chosen threshold. This threshold can be increased until reaching the end of charge voltage.
• Each row of n resistors is therefore arranged between two stages of accumulators. This reduces clutter and the number of components.
• the balancing circuit comprises a plurality of balancing resistors respectively connected in series with a switch, the assembly comprising a balancing resistor and a series switch being arranged in parallel with a accumulator stage while being connected to at least one connection node.
• the balancing circuit comprises m first equal balancing resistances respectively associated with a battery stage.
• the balancing circuit comprises: first balancing resistances respectively in series with a switch and associated with an intermediate stage while being connected to at least one connection node and two second balancing resistors respectively in series with a switch and associated with an extreme accumulator stage being connected to at least one connection node and one pole of the battery module, and a second resistor
• the balancing circuit comprises:
• the system comprises n resistors connected to the terminals of the accumulators of each end stage which are connected to a pole of the battery module, and the balancing circuit comprises a plurality of switches respectively associated with a stage of accumulators.
• the charge control device comprises an average voltage measuring device electrically connected to the terminals of the battery module and to all the connection nodes and able to measure the average voltages of the stages of the battery. accumulators.
• Said control device is for example configured to detect a malfunction of the battery module by monitoring the average voltage across the accumulator stages. It is therefore not necessary to wait for the complete discharge of a stage to detect a malfunction. This detection can be done quickly.
• Said control device is for example configured to detect a malfunction of the battery module when the average voltage across the terminals of at least one of said accumulator stages diverges from the average voltages across the other accumulator stages.
• Said control device may be configured to detect a malfunction of the battery module when the average voltage across at least one accumulator stage drops and the average voltages of the other accumulator stages increase.
• Said control device is for example configured to detect a malfunction of the battery module in case of discharge of at least one accumulator stage.
• the control device may comprise a charger of the battery module and the average voltage measuring device may control the charger to stop the charging of the battery module, for example when the average voltages of the stages have to be balanced.
• the average voltage meter can still completely shut down the charger when all stages have reached the end of charge voltage.
• the system comprises at least two battery modules arranged in series, and an isolation device respectively associated with each battery module and comprising a first switch and a second switch.
• the first switch is arranged in series with the associated battery module and configured to be closed when the associated battery module is operational and open in the event of a malfunction of said battery module
• the second switch is arranged as a bypass of the associated battery module and configured to be open when the associated battery module is operational and closed in the event of a malfunction of said battery module.
• Said control device is for example able to apply an opening control signal of the first switch and to apply a closing control signal of the second switch associated with a battery module in the event of detecting a malfunction of said battery module.
• the isolation device makes it easy to isolate one of the battery modules, for example in case of malfunction with a short-circuited battery.
• the Other battery modules can continue to be used this ensures some continuity of service.
• the invention also relates to a method of balancing a battery module of a system as defined above, said method comprising the following steps:
• a threshold for triggering the balancing is determined
• At least one accumulator stage is detected whose average voltage reaches a predefined plateau voltage added to the determined balancing trip threshold
• the charging of the battery module is stopped when the average voltage of at least one accumulator stage reaches a predefined plateau voltage added to the determined balancing trip threshold
• At least one accumulator stage of lower average voltage than the average voltage of the other accumulator stages is determined, the closing of the switch in parallel with each accumulator stage of higher average voltage is controlled than the stage a lower average voltage accumulator, whereby the accumulators (A) of the higher average voltage accumulator stages are discharged through the balancing circuit, and
• the charge of the battery module is restarted when the equilibrium is reached between the average voltages of all the accumulator stages of the battery module.
• the determination of the threshold for triggering the balancing comprises the following steps: the difference between the plateau voltage and a predefined end of charge voltage is determined,
• said difference is divided by a predefined number n of accumulators in an accumulator stage, the result obtained is said threshold for triggering the balancing.
• the threshold to be added to the plateau voltage is gradually increased until a predefined end of charge voltage is reached.
• FIG. 1 is a schematic representation of a system comprising an example of battery and balancing circuit according to the state of the art
• FIG. 2 is a schematic representation of a system comprising a battery module according to the invention.
• FIG. 3 is a schematic representation of a system comprising a battery module according to the invention, a balancing circuit, a voltage measuring device and a charger;
• FIG. 4 is a schematic representation of the battery module of FIG. 2 on which a balancing current is represented;
• FIG. 5 illustrates an exemplary balancing circuit comprising balancing resistors
• FIG. 6a is a schematic representation of a system comprising the battery module of FIG. 4 with the balancing circuit of FIG. 5;
• FIG. 6b is a schematic representation of a system comprising the battery module of FIG. 2 with a balancing circuit according to a second embodiment
• FIG. 7a is a schematic representation of a system comprising the battery module of FIG. 2 with a balancing circuit according to a third embodiment
• FIG. 7b is a schematic representation of a system comprising a variant of the battery module with a balancing circuit without balancing resistor;
• FIG. 8 is a schematic representation of the battery module of FIG. 2 during a malfunction of an accumulator of the battery module;
• FIG. 9 schematically illustrates the external currents during the malfunction of an electrochemical cell of the battery module of FIG. 8;
• FIG. 10 schematically illustrates the flow of a current from the balancing circuit when a malfunction of an electrochemical cell of the battery module
• FIG. 11 schematically shows an isolated switched battery module
• FIG. 12 schematically illustrates a battery including several modules of FIG. 11 in a normal operating mode
• FIG. 13 illustrates the battery of FIG. 12 in an operating mode in which one of the modules includes a faulty accumulator.
• FIG. 2 schematically shows a system comprising an accumulator battery module 1 according to the invention and a charge control device.
• the battery module 1 has a negative pole N and a positive pole P of large sections.
• the load control device comprises in particular a balancing circuit 2 connected to the P and N poles of the battery module 1.
• the charge control device may further comprise a charger 3 connected to the battery module 1 to charge the module. Battery 1 (see Figure 3).
• the invention applies in particular to LiFeP04 lithium-ion iron phosphate type battery modules.
• An accumulator according to LiFeP04 technology has a large voltage tolerance. Indeed, according to LiFeP04 technology, the maximum voltage is of the order of 4.5V, the margin between the end of charge voltage and the destruction voltage of the battery is large, unlike other Lithium chemistries. Indeed, the voltage specified at the end of charging is 3.6V, so the voltage margin is of the order of IV. For the other chemistries which have an end of charge voltage of the order of 4.2V, the margin is only 0.3V between the end of charge voltage of the order of 4.2V and the maximum voltage of the order of 4.5V.
• the battery module 1 is made in the form of a matrix comprising at least two columns and at least two lines, for example n columns and m rows.
• Each branch Br comprises at least two accumulators Aij connected in series. And these branches are paralleled by their extremities.
• the ends of the branches Br, - are connected to the poles P and N.
• branches Br have the same number of accumulators in series.
• a stage of accumulators And is defined by the set of accumulators which correspond to the same index i at a line of the matrix defining the battery module 1.
• the battery module 1 comprises a predefined number n of branches Br, and a predefined number m of stages Et ;.
• the index i is a natural number corresponding to the number of accumulator stages and varies from 1 to m, and the index] is a natural number corresponding to the number of branches and varies from 1 to n.
• Each floor And comprises at least two accumulators Ay, or electrochemical cells.
• Each floor And comprises a predefined number n of accumulators Aij.
• the index j also corresponds to the number of accumulators in a stage Et ; and varies from 1 to n.
• Accumulators A are advantageously chosen as similar. In the case of accumulators of unequal quality or different state of charge, it is possible to make a first initial charge slower so as to allow time accumulators to equilibrate. This charge being made only once at the end of manufacture of the battery, its impact can be considered as minor because only time consuming for a battery manufacturer. This is a compromise between the cost and a balancing time and therefore a longer immobilization at the factory outlet.
• the first branch Bri includes accumulators A to A m connected in series.
• the second branch Br 2 includes accumulators Ai, 2 to A m , 2 connected in series.
• the branch Br includes accumulators Aij to A m j connected in series.
• the last branch Br n includes accumulators Ai, n to A m , n connected in series.
• the battery module 1 therefore comprises at least one matrix of m battery stages Et; and n battery branches Br, in parallel.
• the main current of charging and discharging accumulators passes from the accumulator Ay to the accumulator A i + ij then to A i + 2 , j, and so on along the serialization of accumulators Aij, .., Ay,. .. At mj -, then this current collects at the poles P and N via the electrical connections of large sections.
• Each accumulator Ay of the matrix is electrically connected by a link dimensioned for the charging and discharging currents with the accumulator Ai + y.
• the battery module 1 further comprises secondary electrical connections provided with resistors Rt between all the accumulators Ay.
• the battery module comprises a plurality of resistors Rt respectively electrically connected to the intermediate point between two accumulators Ay, Ai + ij of two adjacent accumulator stages And ; , And i + i and a third predefined number of NC connection nodes ; respectively connected to a set of n resistors Rt connected to the intermediate points of the accumulators Ay, A i + ij of two adjacent accumulator stages Et ; , And i + i.
• the battery module 1 comprises at least one row of n resistors Rt connected to the accumulators Ay, A i + ij of two adjacent accumulator stages Et ; , And i + i.
• the battery module 1 comprises the predefined number p of rows of resistors Rt. According to the embodiment illustrated in FIG. 1, this third predefined number p_ satisfying the relation (1):
• p m - 1 where m is the number of accumulator stages And ; .
• Each row of resistors Rt comprises n resistors Rt, which is the same number as accumulators Aij in an accumulator stage Et ; .
• the set of accumulators Aij a stage And ; have a terminal connected to a common NG connection node through the resistors Rt.
• the other terminal of the accumulators Ay can be connected to another common connection node NC; via other respective resistors Rt.
• the resistors Rt of the first row of resistors connect the negative terminals of the accumulators Ai j of the first stage Eti to the common connection node NG and, on the other hand, connect the positive terminals of the accumulators A. 2j of the second stage And 2 to this common NG connection node.
• the resistors Rt of the row of resistors of order i connect the negative terminals of the accumulators Ay of the stage Et; to the common connection node NG and on the other hand connect the positive terminals of the accumulators A i + ij of the second stage Et i + i to this common connection node NG.
• the load control device is also connected to all the common NG connection nodes.
• the balancing circuit 2 is connected to the common connection nodes NG.
• the main current in a branch passes through all the accumulators connected in series in this branch.
• no transverse current flows through the resistors Rt.
• the dimensioning of the resistances Rt is defined by a compromise between various parameters on which one wants to act, such as:
• the dimensioning must therefore be done according to the architecture of the module and accumulators used.
• resistors Rt of large value severe ohms or even tens of ohms
• the range of values of the resistors Rt may be of the order of 10 ⁇ to 1kH.
• the resistors Rt may for example be chosen with a value of the order of 50 ⁇ .
• the voltage measured at the common node NC corresponds to the average voltage of accumulators Aj.
• the load control device may comprise an average voltage measuring device 5 of the accumulator stages And ; (see Figure 3).
• This average voltage measuring device 5 is electrically connected to the common nodes NC; to which the accumulator stages Et are respectively connected ; via the resistors Rt and the terminals P and N of the battery module 1.
• the invention is distinguished from the state of the art by measuring the average voltage of a given stage while conventionally in the prior art the measurement of the voltage of all the accumulators is required. For this, in the prior art, the paralleling of the accumulators by strong current link or fuses cause all the accumulators of the given stage have the same voltage.
• the plateau voltage is for example of the order of 3.3V. If the measured average voltage is of the order of this plateau voltage added to a given threshold, for example is of the order of 3.4V, the accumulators are considered to have respectively a minimum voltage equal to this plateau voltage of 3 3V. Indeed, by construction, the dispersion of the accumulators according to the LiFePO4 technology is low, in particular of the order of 10%, so when the average measured voltage is of the order of 3.4V, the accumulators of this stage all have a minimum voltage of the order of 3.3V.
• the average voltage Umoy provides information on the voltages of the accumulators of the given floor to 100mV in the example described. A battery balancing strategy will be described later in more detail.
• the balancing circuit 2 can thus detect a failure, for example by noting that a stage discharges or charges differently from the other stages. Since a short-circuited accumulator remains connected in parallel with the other accumulators of the stage, it can be detected that the other accumulators are gradually discharged therein. This makes it possible to quickly detect that an accumulator is in fault. The operation in case of malfunction of an accumulator Ay will be detailed later.
• the load balancing circuit 2 is electrically connected to each of the stages Eti to Et m , as previously described by the common nodes NC; and are also connected to the N and P terminals of the battery module 1.
• the balancing circuit 2 is configured to implement load balancing of the accumulators j of these stages Et ; , depending on the monitoring of their state of charge. A balancing strategy will be described in more detail later.
• the balancing circuit 2 comprises a predefined number of balancing resistors Req.
• the balancing circuit 2 comprises, according to a first embodiment illustrated in FIGS. 5 and 6a, a first balancing resistor Req in series with a switch 4 for each accumulator stage And;
• the value of the first balancing resistors Req is chosen as a function, in particular, of the performance of the accumulators used, the desired balancing time, and the dissipation that may be admitted in the resistor, the electronic support, and more generally the battery module. .
• These first balancing resistors Req can have a value of the order of 10 ohms.
• the first resistors Req and switches 4 associated in series arranged in extreme position can be connected firstly to a terminal P or N of the battery module 1 and secondly to NC common connection node ;.
• the balancing current Ieq is defined by the first balancing resistors Req but also the resistors Rt which when the switches 4 are closed are in series with the first balancing resistors Req.
• the equivalent resistance of the circuit corresponds to a first balancing resistor Req added twice to a resistor Rt divided by the number n of resistors Rt, according to relation (2):
• the equivalent resistance corresponds to a first balancing resistor Req added to a resistor Rt divided by the number n of resistors Rt, according to relation (3):
• the equivalent resistance is therefore lower for the extreme stages Eti and Et m , and the current is therefore stronger.
• the balancing circuit 2 comprises a first balancing resistor Req in series with a switch 4 for each intermediate stage of accumulators Et 2 to Et m _i, and for the extreme stages Eti and Et m a second balancing resistor Req 'also in series with a switch 4. It is also possible to provide an alternative embodiment making it possible to eliminate at least some of the balancing resistors, in particular the first balancing resistors Req of the embodiment illustrated in FIG. 6b, since the resistors Rt can serve as resistor balancing, as shown in Figure 7a.
• the balancing circuit In particular according to the embodiment of FIG. 7a, the balancing circuit
• n resistors Rt are connected to the terminals of the accumulators Ay of the first stage Eti and to the pole P, and n other resistors Rt are connected to the terminals of the accumulators A mj - of the last stage Et m and to the pole N.
• each accumulator Aj is connected to a resistor Rt at each of its terminals.
• the additional resistors Rt connected to the pole P are connected to a common node NCo and the additional resistors Rt connected to the pole N are connected to a common node Nc m .
• the third predefined number satisfies the following relation (5):
• the resistors Rt make it possible to keep the accumulators Ay in temperature or to heat them in cold weather, for example by a transfer of heat to the two terminals of the accumulators Aj.
• a balancing strategy according to the invention consists in waiting for the average voltage Umoy of a stage Et; reaches a plateau end voltage, for example of the order of 3.3V plus a threshold chosen for a storage battery 1 according to LiFeP04 technology.
• the measuring device 5 can measure the average voltage Umoy of a stage Eti.
• a charge stop control signal coming for example from the measuring device 5 is transmitted to the charger 3 to stop the charging of the battery module 1 and control the balancing between the stages Eti to Et m .
• the average voltage measuring device 5 is able to control the charger 3.
• the plateau corresponding to a charge of between 10% and 90% is of the order of 3.3V. If an imbalance appears, it will therefore be between this plateau voltage of 3.3V and the end of charge voltage generally of the order of 3.6V.
• the maximum difference is therefore of the order of 0.3V. This maximum deviation is divided by the number n of branches Br, of the battery module 1 and becomes 0.3V / n.
• This value of 0.3V / n can be the starting point for a preferred balancing solution to set the balancing trip threshold to be added to the 3.3V plateau voltage to stop the load and start the load. balancing. According to the example described, it is chosen to stop the charge as soon as the measured average voltage reaches 3.3V + 0.3V / n, for example 3.36V for a battery module 1 comprising five Br branches.
• the mean voltages Umoy of the accumulator stages Et are compared ; between them, so as to determine at least one stage of accumulators And; average voltage lower than the average voltage of the other battery stages.
• the accumulators of the higher average voltage storage stage or stages are discharged into the balancing circuit 2, for example through a resistor
• the discharge of the accumulators of the stage being balanced is represented by the balancing current leq flowing from the accumulator stages to the balancing circuit 2 to discharge for example in the balancing resistors Req or
• the balancing current in each accumulator j corresponds to the current
• the balancing current in each accumulator is therefore very low.
• the balancing current Ieq is of the order of 250mA, the balancing current
• each accumulator A of a stage Eti is therefore of the order of 250 mA / n or a few tens of mA at the most for ten accumulators j in parallel.
• This operation can be done for several floors at the same time.
• One variant is to provide sequential balancing of two stages of successive accumulators.
• the balancing operation is repeated until the average voltages of the higher voltage stages reach the average voltage of the lower voltage stage.
• the threshold chosen can be gradually increased to accelerate the balancing.
• the measured average voltage value can be raised to 3.6V and thus obtain a complete load at 100% of the stage. It is possible in the example described to have a threshold evolving in this way: 3.36V-3.40V-3.45V-3.50V-3.55V-3.60V.
• the final charge stop is done as an example when all stages are at
• a final charge stop threshold of less than 3.6V can be chosen, for example between 3.3V and 3.6V
• the voltage measuring device 5 can determine the presence of a faulty accumulator by identifying a stage at the terminals of which the voltage varies abnormally with respect to the other stages, either during a charge or during a discharge.
• the neighboring accumulators will inject a current into the battery A 3; 3 in short circuit.
• resistors Rt Due to the presence of the resistors Rt, the currents between the branches are weak because limited by the resistors Rt. The use of resistors Rt thus makes it possible to protect the accumulators j simply and at a lower cost.
• the transverse load currents from neighboring accumulators are relatively limited.
• the current is limited in the neighboring branches of the faulty accumulator A 3 , 3 (shown in bold in FIG. 8).
• the current is limited to ⁇ in the accumulator A 3; 3 in default. This current is low, for example less than 100mA, which will help to discharge the stage Et3 containing the faulty accumulator A 3; 3 in a very slow manner.
• the overcurrent is limited in amplitude and the battery A 3; 3 in default only dissipates a small amount of energy from its neighbors. It is not likely to overheat violently. The risk of fire starting is eliminated or greatly minimized.
• the accumulators A respectively have a voltage of the order of the plateau voltage, or 3.3V, in normal operation.
• the measured average voltage Umoy of the stage Et3 will fall by a value corresponding to the plateau voltage, ie 3.3V, divided by the number n Br branches, five in the example of Figures 8 and 9,
• the average voltage Umoy of the stage Et3 comprising the accumulator A 3; 3 in default will be of the order of 2.64V (see Figure 9).
• a branch Br has a voltage of the order of the plateau voltage 3.3V multiplied by the number m of stages Et, therefore in the example illustrated with five stages Et ; the voltage of a branch Br is of the order of 3.3 V x 5 5 or 16.5V.
• the branch Br 3 presenting the battery A 3; 3 in default will drop by a value of the order of the battery voltage of the accumulators, here 3.3V, ie from 16.5V to 13.2V.
• the branch Br 3 having its voltage dropping from 16.5V to 13.2V a large current I flows through the ends (see Figure 9).
• the current flowing in the transverse branches contributes to recharge the accumulators in series with the faulty accumulator by the external connections of the battery module 1 as shown in FIG. 9.
• This transient current thus distributes the plateau voltage on the accumulators in series with the one in default by recharging them.
• the measuring device 5 measures a voltage which has fallen with respect to the plateau voltage, for example here 2.64V, for the stage Et 3 comprising the accumulator A 3 , 3 in error while it measures a average voltage which has increased on the stages remaining for example here 3,465V corresponding to the average of four accumulators at 3,3V and an accumulator in series with the faulty accumulator A 3; 3 to 4,125V.
• the accumulators of the branch Br 3 comprising the accumulator A 3; 3 in default and having an overvoltage as explained above are discharged in the adjacent accumulators of the stage concerned.
• the other stages apart from the stage Et 3 comprising the faulty accumulator discharging completely, the other stages progressively reach a voltage close to the plateau voltage at 3.3V.
• Another detection mode may be to observe the discharge of the accumulators in parallel in the faulty accumulator.
• the current flowing through the resistor Rt connected to the faulty accumulator A 3; 3 is smaller than a current F coming from the balancing circuit 2.
• the current of discharge from the accumulators of the stage Et3 comprising the faulty accumulator A3 may be completely or partially compensated by the current F coming from the balancing circuit 2, according to the dimensioning of the balancing resistors Req, Req '.
• A3, 3 do not discharge in the latter.
• FIG. 11 shows a switched module, that is to say a battery module 1 as defined previously associated with a first power switch 6 and a second power switch 7.
• the first switch 6 is arranged in series with the battery module 1.
• the second switch 7 is arranged in parallel with the battery module 1.
• the switches 6 and 7 may be MOSFET transistors, which can easily be appropriately sized at a relatively low cost.
• the control device is able to control the closing and opening of the switches 6, 7.
• the switches 6, 7 form an isolation device 8 of the associated battery module 1.
• the first switch 6 is configured to be closed and the second switch 7 is configured to be open.
• the opening of the first switch 6 is controlled and the closing of the second switch 7 is controlled.
• a storage device also called battery, for example whose nominal voltage is for example greater than 100V, generally comprises several battery modules 1 connected in series as shown in Figure 12.
• the battery has two + and - power output poles.
• Each battery module 1 is as previously defined with several accumulator stages Et ; in series defining several branches Br, in parallel and is associated with two power switches 6, 7.
• the battery modules 1 are all operational. Consequently, their first associated switches 6 are closed and their associated second switches 7 are open, so that the battery modules 1 are connected in series.
• control device can advantageously command short-circuiting this battery module 1 to ensure continuity of service of the rest of the battery.
• the control device detects a malfunction as explained above by monitoring the average voltages of the stages Et, the first switch 6 is open and kept open in order to isolate the module automatically. battery 1 in case of malfunction. The closing of the second switch 7 is controlled.
• the battery can be used in a degraded way ensuring continuity.
• the security system as described above makes it possible to obtain lithium-ion batteries tolerant to the short circuit or open circuit failure of an accumulator, provided with balancing circuits to maximize the life of the accumulators Aj, with the advantage of minimizing the number of circuits balancing and monitoring the high and low voltages of all accumulators.
• the resistors Rt connect the accumulators of a stage to a common connection node NG on which the average voltage Umoy of the stage can be measured.
• the detection of a faulty accumulator can take place instantaneously without having to wait for the complete discharge of the accumulator stage comprising the accumulator by detecting a variation of the average voltage at the common node, for example a fall in the average voltage of one stage while the tensions of the other floors increase.
• the resistors Rt are simple components making it possible to limit the current at a lower cost in order to protect the accumulators in the event of a short circuit in particular.
• the distribution of the resistors Rt within the battery module 1 ensures a better heat distribution.
• the plurality of resistors Rt makes it possible to heat up or maintain the temperature of the accumulators A of the battery module 1, especially when used in cold weather.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Chemical & Material Sciences (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Charge And Discharge Circuits For Batteries Or The Like (AREA)
• Secondary Cells (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=49753250

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (15)

Family Cites Families (7)

• 2013
  • 2013-05-09 FR FR1354217A patent/FR3005535B1/fr not_active Expired - Fee Related
• 2014
  • 2014-05-07 WO PCT/EP2014/059399 patent/WO2014180935A1/fr active Application Filing
  • 2014-05-07 EP EP14723765.5A patent/EP2994341A1/de not_active Withdrawn
  • 2014-05-07 US US14/889,046 patent/US20160118819A1/en not_active Abandoned

Also Published As

Similar Documents

Legal Events