BATTERY WITH GROUPS OF STORAGE CELLS, EACH ASSOCIATED WITH CONVERSION MODULES, FOR SUPPLYING VOLTAGE OF DIFFERENT TYPES

Description

[0001] The invention relates to rechargeable batteries which comprise several groups of electrical energy storage cell(s) and which are intended to equip certain systems.

[0002] Some systems, such as certain vehicles, of the all-electric or hybrid type and possibly of the automobile type, generally include in their base, at least one rechargeable battery comprising a casing housing groups of cell(s) responsible for storing electrical energy. These cells can, for example, be of the Li-ion or Ni-Mh or lead or Lithium-Metal-Polymer (or LMP) or even Sodium-ion type.

[0003] For example, in an all-electric or hybrid vehicle, this type of battery can be responsible for supplying different types of electrical equipment (or components) with different voltages, on different outputs. Thus, a first output can be dedicated to supplying low voltage DC power electrical equipment (typically 450 V), a second output can be dedicated to supplying three-phase AC electrical equipment (s), and a third output can be dedicated to supplying very low voltage DC electrical equipment of an on-board network (typically 12 V).

[0004] Such a battery generally comprises management means responsible for ensuring, via appropriate electronic cards, a measurement of the voltage on the output terminals, a measurement of the temperature of each group of cell(s) and a measurement of the internal current. These management means are also responsible for controlling the conditions and state of charge of each group of cell(s) to protect the battery by preventing it from operating outside a normal operating range predefined by limit charge and discharge currents, limit temperature ranges and limit operating voltage levels of the groups of cell(s).

[0005] It should be noted that this type of battery generally also includes means for turning it off in the event of an accident or maintenance work, an output fitted with a switch with a pre-charge circuit, a switch to activate rapid charging, and fuses on each input / output.

[0006] Furthermore, the operation of this type of battery is supervised by internal supervision means, using algorithms that make it possible in particular to calculate its state of charge (or SOC ("State Of Charge")), to determine its state of health (or SOH ("State Of Health")), to manage the balancing of the groups of cell(s), to communicate with a vehicle computer, to limit current draws (discharge or recharge current), and to ensure its thermal management by regulating the flow of a heat transfer liquid passing through it and / or partially surrounding it.

[0007] Today, in order to power various types of electrical equipment appropriately, it is necessary to install various energy conversion devices downstream of the battery output. Thus, a first DC-DC (continuous / continuous) converter, a possible charger, and an inverter are installed downstream of the output.

[0008] These energy conversion devices, external to the battery, are quite bulky and quite expensive, and cannot secure the battery when it is subject to an internal short circuit which instantly results in a very significant release of electrical energy linked to the discharge of all the cells.

[0009] In addition, the first DC-DC converter induces energy losses and the three-phase voltages produced by the inverter are loaded with harmonics which induce additional iron losses in an electrical machine (for example, a motor). For its part, the inverter is also a source of electromagnetic pollution which can degrade the operation of the electrical machine.

[0010] In addition, it is necessary to install numerous external filters made of inductive and capacitive elements in the electrical architecture downstream of the battery in order to obtain an acceptable level of electromagnetic compatibility for all electrical equipment. However, these external filters are particularly bulky.

[0011] It has certainly been proposed in patent document FR 2977986 to equip the battery with switching means intended to connect the cells in series and / or in parallel, in order to control the voltage delivered to the terminals. But this solution does not allow several (at least two) different types of voltage (alternating, three-phase, direct) to be generated at the battery output. Consequently, it is always necessary to use certain energy conversion devices downstream of the battery to define the different types of voltage required by the electrical equipment of the system in question.

[0012] Furthermore, the state of the art is known from document US2016311328A1 and document WO20161741117A1 corresponding to the preamble of claim 1.

[0013] The invention is intended in particular to improve the situation.

[0014] For this purpose, it offers a battery comprising electrical energy storage cells and at least two main outputs capable of delivering voltages of different types and intended to power different electrical equipment in a system.

[0015] This battery also includes: conversion modules each installed at the output of a group of at least one cell and each comprising a first DC-DC type converter and capable of converting a first DC voltage supplied by the output of the associated group into a second predefined DC voltage, each of the conversion modules comprising: an inverter capable of converting this first DC voltage into a third predefined AC voltage, and interconnection means capable of connecting an output of the first converter or an output of the inverter to an output of another group or to one of the main outputs as a function of a received instruction, auxiliary control means capable of generating control signals capable of placing said associated inverter in a state which is a function of a received instruction, each inverter being arranged in the form of an H-bridge,each conversion module comprising control means suitable for placing its H-bridge in a state depending on a control signal generated by said auxiliary control means, main control means suitable for generating each instruction dedicated to each conversion module depending on a received definition of the type of voltage which is required to supply at least one of the electrical equipment, , characterized in that each conversion module comprises a second DC-DC type converter capable of converting said first direct voltage into a fourth predefined direct voltage intended to supply said associated control means.

[0016] Thus, it is now possible to produce internally in the battery any type(s) of voltage (or current) according to requirements, without having to provide energy conversion devices downstream of the main outputs of this battery.

[0017] The battery according to the invention may include other characteristics which may be taken separately or in combination, and in particular: the auxiliary control means associated with each group may be capable of determining a voltage at the terminals of the associated group and a temperature within the associated group, and of estimating a current charge state of the associated group; it may comprise a multiplexed bus coupled to the main control means and to each of the conversion modules. In this case, each conversion module may comprise a controller coupled to the multiplexed bus; it may comprise three main outputs capable of respectively delivering voltages of three different types; the voltage types may be chosen from a very low direct voltage, a low direct voltage, and a single-phase or three-phase alternating voltage.

[0018] The invention also proposes a system comprising electrical equipment and at least one battery of the type presented above and capable of powering this electrical equipment. Such a system may, for example, constitute a vehicle of the all-electric or hybrid type, and possibly of the automobile type.

[0019] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which: there figure 1 schematically and functionally illustrates an example of an all-electric vehicle comprising a rechargeable battery according to the invention, the figure 2 schematically and functionally illustrates an exemplary embodiment of a rechargeable battery according to the invention, and the figure 3 schematically and functionally illustrates an exemplary embodiment of a conversion module associated with a group of cell(s) and which can be part of a rechargeable battery according to the invention.

[0020] The invention aims in particular to propose a battery B1 comprising storage cells capable of storing electrical energy and at least two main outputs SPk capable of delivering voltages of different types in order to power different electrical equipment of a system V.

[0021] In the following, it is considered by way of non-limiting example that the battery B1 is part of an all-electric motor vehicle, such as a car. However, the invention is not limited to this type of system. It relates in fact to any type of system comprising at least one rechargeable battery (comprising groups of cell(s)), and in particular vehicles, whether land, sea (or river) or air, installations, possibly industrial, and buildings. It should also be noted that when the system is a vehicle, its powertrain (or powertrain) may be all-electric or hybrid (thermal / electric).

[0022] Furthermore, it is considered in the following, by way of non-limiting example, that the (storage) cells of the (rechargeable) battery B1 are of the Li-ion type. But the invention is not limited to this type of cell. It relates in fact to any type of cell capable of storing electrical energy with a view to restoring it. Thus, the cells could also be of the Ni-Mh, or lead, or Sodium-ion, or even Lithium-Metal-Polymer (or LMP) type, for example.

[0023] We have schematically represented on the figure 1 a V system, here a motor vehicle, comprising a transmission chain comprising an all-electric powertrain (or GMP), a CS supervision computer capable of supervising (or managing) the operation of the GMP, and CP electrical power equipment. It should be noted that the GMP could also be of the hybrid type (thermal / electric).

[0024] The GMP notably comprises electrical equipment MM defining a motor machine, a coupling means MCP, and at least one battery B1 according to the invention.

[0025] The prime mover MM is an electric (and therefore non-thermal) machine or motor intended to provide torque for at least one train TV of the vehicle V via the coupling means MCL. It will be noted that in the non-limiting example of embodiment illustrated, the prime mover MM provides torque for the front train TV via the coupling means MCL. But in an alternative embodiment it could provide torque to the rear train TR only or to the front train TV and rear train TR, via the second coupling means MC2.

[0026] This MM prime mover here supplies its torque to a drive shaft AT which is coupled to the front axle TV, via the coupling means MCL. Here, given the type of vehicle described, the front axle TV and rear axle TR include wheels.

[0027] The operation of the MM driving machine is controlled by the CS supervision computer.

[0028] Battery B1 is, for example, installed here in the underbody of vehicle V.

[0029] This battery B1 comprises a case housing, in particular, groups Gj (j = 1 to N) of at least one electrical energy storage cell and at least two main outputs SPk capable of delivering voltages of different types and intended to supply different electrical equipment MM, CP, B2 of the system V (here a motor vehicle). The value of N, which fixes the number of groups Gj depends on the needs of the system V. It can therefore take any value greater than or equal to two.

[0030] It should be noted that when a group Gj comprises several cells (for electrical energy storage), the latter can be connected in series or in parallel within their group Gj.

[0031] For example, and as illustrated without limitation on the figures 1 And 2 , in an all-electric vehicle, battery B1 can include three main outputs SP1 to SP3 (k = 1 to 3) capable of delivering voltages of three different types respectively. These voltage types can be chosen from a very low DC voltage, a low DC voltage, and a three-phase AC voltage. Thus: a first main output SP1 (k = 1) can be dedicated to the power supply of a service battery B2 and / or to supply very low direct voltage (typically 12 V) to electrical equipment of an on-board network (not shown), a second main output SP2 (k = 2) can be dedicated to the single-phase or three-phase alternating current power supply of electrical equipment(s), such as for example the prime mover MM, and a third main output SP3 (k = 3) can be dedicated to the low direct voltage power supply (typically 450 V) to power electrical equipment(s), such as for example a compressor CP of a heating / air conditioning circuit or heating resistors (possibly of the PTC type) of a heating circuit.

[0032] It will be noted that the battery B1, according to the invention, can have any number of SPk outputs, provided that this number is greater than or equal to two.

[0033] As it appears on the figure 2 , the battery B1, according to the invention, also comprises, inside its housing, conversion modules MCj and main control means MCP.

[0034] Each MCj conversion module is installed at the output of a Gj group of cell(s) and includes, as illustrated in the figure 3 , at least a first converter CV1, an inverter ON and interconnection means MCM. It is important to note that, in an alternative embodiment, each group Gj of cell(s) could be part of a conversion module MCj.

[0035] The first converter CV1 of each conversion module MCj is of the DC-DC (direct / direct) type and capable of converting a first direct voltage vc1 supplied by the output of the associated group Gj into a second predefined and preferably adjustable direct voltage vc2. For example, when each cell is of the Li-ion type, it can deliver to its terminals, in normal operation, a first direct voltage vc1 of approximately 3.3 V nominal. In this case, a group Gj of four cells can deliver to its terminals, in normal operation, a first direct voltage vc1 of approximately 13.2 V nominal.

[0036] The second DC voltage vc2 can, for example, be between 8 V and 16 V depending on the value of the first DC voltage vc1, and be delivered at a power of 75 W.

[0037] The ON inverter of each MCj conversion module is capable of converting the first direct voltage vc1 into a third predefined alternating voltage vc3.

[0038] The third alternating voltage vc3 can, for example, be equal to +vc1, -vc1 or 0 (zero), and make it possible to generate on the main output SP2 of the battery B1 a system of alternating voltages necessary, for example, for the operation of the prime mover MM.

[0039] The interconnection means MCM of each conversion module MCj are suitable for connecting an output of the first associated converter CV1 or an output of the associated inverter ON to an output of another conversion module MCj' (j' ≠ j) powered by the group Gj' or to one of the main outputs SPk depending on a received instruction. The conversion modules MCj can thus be associated in series or in parallel in order to deliver the voltages and powers according to the main outputs SPk.

[0040] The main control means MCP are capable of generating each instruction dedicated to each conversion module MCj based on a received definition of the type of voltage which is required to supply at least one of the electrical equipment MM, CP, B2 of the system V.

[0041] These main MCP control means can, for example, be implemented using a digital signal processor (or DSP), or more generally using a programmable component (for example FPGA or ASIC type).

[0042] By associating each group Gj of cell(s) with a conversion module MCj internally ensuring the conversion functions, and by controlling each of these conversion modules MCj by main control means MCP, it is now possible to produce internally in the battery B1 any type(s) of voltage (or current) as required, without it being necessary to provide energy conversion devices downstream of the main outputs SPk of this battery B1. It will be understood, in fact, that this battery B1 can now deliver on a main output SPk a voltage of a first type for at least one piece of electrical equipment, or on at least two main outputs SPk and SPk' respectively voltages of different types for different types of electrical equipment.It should be noted that it may even be possible to choose the voltage value that battery B1 delivers to a given main output SPk, by appropriately selecting the number of groups Gj used to produce this voltage. It should also be noted that since battery B1 can deliver a very low voltage permanently, it could directly supply the on-board network of vehicle V, thus making it possible to dispense with the service battery B2.

[0043] It should also be noted that the B1 battery may optionally include an ER input for rapid direct current charging or slow charging from an alternating current network (230 V - 50 Hz), and / or a natural three-phase charging input (230 V / 400 V - 50 Hz), possibly directly via one of its main SPk outputs.

[0044] It should also be noted, although this does not appear on the figures 1 à 3 , that the battery B1 may optionally include in addition to the means allowing it to be switched off during an accident or maintenance intervention, and a switch on its second main output SP2 to isolate its recharge from the driving machine MM, and fuses on each main input / output SPk.

[0045] In order to allow the series and / or parallel connection of the second DC voltages vc2, the architectures of these first CV1 converters (DC-DC type and isolated) can, for example, be of the Push-Pull type, or Forward with synchronous rectification, or with isolated interleaved choppers, or even with resonance converter. The topology of these first CV1 converters must allow power reversibility.

[0046] Preferably, each first converter CV1 is an isolated and power-reversible structure. The duty cycle denoted D and the transformation ratio (denoted m) of each first converter CV1 makes it possible to define the second galvanically isolated DC voltage vc2 at the output of the latter (CV1) according to a law that is a function of D, m and vc1, for the group Gj considered.

[0047] For example, if 15 kW are required in total to power electrical equipment connected to the main outputs SPk relating to low DC voltage (for example 450 V) consuming 12 kW and very low DC voltage (for example 12V) consuming 3 kW, then each first converter CV1 is sized to deliver a power of 75 W, if 201 cells are present in the battery B1 (i.e. 201 MCj associated with 201 Gj).

[0048] Thus, to take the previous example, the production of a direct voltage of 450 V for a power of 12 kW can be obtained by the association of 162 cells in the battery B1. The arrangement of these 162 cells can be achieved by the parallel connection of three times 54 conversion modules MCj, each of which first associated converter CV1 would deliver a direct voltage of between 8 V and 9 V.

[0049] Still following this example, the production of a direct voltage of 12 V for a power of 3 kW, usable here by the on-board network, can be obtained by paralleling 39 cells in battery B1. It will be noted that these 39 cells can possibly be dedicated exclusively, by initial configuration, to this production via the first associated converters CV1 connected in parallel and whose output voltage can also be adjusted to ensure the charging of the service battery 11 B2.

[0050] As illustrated without limitation on the figures 2 et 3 , the battery B1 may also comprise a multiplexed bus BM coupled to its main control means MCP and to each of its conversion modules MCj. In this case, each conversion module MCj may comprise a controller CB coupled to this multiplexed bus BM. It will be understood that each controller CB provides the interface between its conversion module MCj and the main control means MCP via the multiplexed bus BM. This allows the exchange of messages between the conversion modules MCj and the main control means MCP.

[0051] For example, multiplexing can be of the CAN (“Controller Area Network”) type.

[0052] Also as illustrated without limitation on the figure 3 , each conversion module MCj also comprises auxiliary control means MCA capable of generating control signals capable of placing the inverter ON in a state which is a function of a received instruction (for example coming from the supervision computer CS). These auxiliary control means MCA can also generate control signals defining the voltage levels vc2 delivered by the first associated converter CV1.

[0053] It will be noted that the auxiliary control means MCA associated with each group Gj can be capable of determining the voltage at the terminals of the associated group Gj and a temperature within the associated group Gj, and of estimating a current state of charge (or SOC) of this associated group Gj. They can then transmit at least each estimated state of charge and each determined temperature to the main control means MCP (here via the multiplexed bus BM).

[0054] Each state of charge can be estimated using an algorithm adapted to the group Gj considered.

[0055] It should also be noted that the main control means MCP can calculate the overall state of charge of their battery B1 at any time. The main control means MCP can also determine the state of health (or SOH ("State Of Health")) of their battery B1, manage the balancing of the groups Gj of cell(s), communicate with the supervision calculator CS of the GMP, limit current draws (discharge and recharge currents), and ensure the thermal management of their battery B1 by regulating the flow of a heat transfer fluid passing through it and / or partially surrounding it.

[0056] The main control means MCP can thus optimize the management of the cells of the battery B1, in order to optimize their lifespan and the autonomy of the vehicle V. They can also, by individual control of each group Gj of cell(s), achieve dynamic balancing and control of the state of charge of these groups Gj when the vehicle V is in operation (groups can be recharged while others, at the same time, are discharging or doing nothing). This management of the groups Gj can be defined according to the mission profiles of the vehicle V. In addition, the individual control of each group Gj of cell(s) makes it possible to limit the use of group(s) Gj whose temperature is the highest in order to maintain a uniform temperature within the battery B1.

[0057] When each conversion module MCj comprises a controller CB, its auxiliary control means MCA are connected to the multiplexed bus BM in order to receive each instruction which concerns them and from which they will generate the aforementioned control signals for the inverter ON and the first associated converter CV1.

[0058] These MCA auxiliary control means can, for example, each be arranged in the form of a programmable digital component (such as a microcontroller or a DSP).

[0059] Each ON inverter is arranged in the form of an H-bridge, well known to those skilled in the art. In this case, as illustrated in the figure 3 , each conversion module MCj comprises control means (or “drivers”) MP capable of placing its H bridge ON in a state which is a function of a control signal generated by its auxiliary control means MCA.

[0060] As illustrated in the figure 3, these MP control means may also be capable of placing the first associated converter CV1 in a state which is a function of a control signal generated by the associated auxiliary control means MCA and defining the voltage level vc2 to be delivered by this first converter CV1.

[0061] Each H-bridge may, for example, comprise four electronic components such as power transistors (possibly of the MOSFET type) whose respective states can be controlled by voltage commands. These four power transistors may be arranged in pairs in two half-bridges. In this case, the MP control means may, for example, be arranged in the form of two Bootstrap-type circuits, well known to those skilled in the art. These two Bootstrap-type circuits may themselves be powered by a second boost-type converter CV2 (or “step-up regulator”) if the number of cells in group Gj is not sufficient to ensure a sufficient control voltage. It will be noted that if group Gj is made up of a sufficient number of cells in series, the second converter CV2 is not necessary.

[0062] For example, the power transistors can be controlled so as to place the H-bridge (i.e. the ON inverter) in three different states. These three states can be materialized by a variable denoted uj associated with MCj (or Gj) and which can take three values ​​-1, 0, +1. For example, the first state associated with the first value of uj equal to -1 can allow the inversion of the first (input) voltage vc1, the second state associated with the second value of uj equal to 0 can allow a zero voltage to be defined at the output of the ON inverter, and the third state associated with the third value of uj equal to +1 can allow a voltage to be delivered at the output equal to that vc1 delivered by the associated group Gj of cell(s). The output voltage vc3 of an ON inverter associated with the group Gj of cell(s) can then be expressed by the formula vc3 = vc1*uj.

[0063] This three-state control principle makes it possible to produce a positive, zero or negative voltage at the main output of battery B1 and, for example, to recharge at least one group Gj of cell(s) while at least one other group Gj' of cell(s) is discharging or doing nothing. Thus, the invention makes it possible, for example, not to use two groups Gj and Gj' by placing the associated ON inverters in their second state (uj = 0), and depending on the direction of the current to discharge a group Gj" by placing the associated ON inverter in the third state (u3 = +1), or to discharge two groups Gj and Gj' by placing the associated ON inverters in the third state (uj = uj' = +1), and to recharge a group Gj" by placing the associated ON inverter in the first state (uj" = -1).

[0064] Each possible second converter CV2, of the DC-DC type, of a conversion module MCj, can, if necessary, convert the first direct voltage vc1 into a fourth predefined direct voltage vc4 intended to supply the associated MP control means. This fourth direct voltage vc4 can, for example, be equal to 12 V for a power of 1 W.

[0065] It should also be noted that the use of high-frequency power semiconductor components integrated in the same MCj conversion module, possibly on the same substrate, can, for example, be considered in GaN or Si technology.

[0066] The invention offers several advantages, including: it improves operational safety due to the possibility of disconnecting (or not using) at least one group of cell(s) that is faulty or whose temperature is too high, while keeping the system functional, or even disconnecting all the cells of the battery in the event of a prolonged shutdown of the system or in the event of an incident, it avoids harmonics in the injected current, and therefore a significant reduction in iron losses, it allows the internal use of DC / DC converters operating at high current and very low voltage (typically less than 20 V), unlike current external DC / DC converters which operate at high current and low voltage (typically 400 V), it can eliminate the need for a charger in the battery, but in this case the latter must have switches that can be switched off (absence of pre-charge circuit) to switch from traction / propulsion mode to recharge mode,it allows easy adaptation of the battery to the different currents delivered by the network (direct, alternating, single-phase, three-phase), it makes it possible to improve efficiency while reducing the overall volume and overall mass compared to a battery of the prior art associated with an inverter, converters and an external and conventional charger, it makes it possible to reduce costs due to the absence of an inverter, converters and an external and conventional charger, or even a service battery (of the 12 V type), it can make it possible to operate electrical machines with voltages which are higher than the current voltages of approximately 450 V, without having to resort to classes of power components which are much more expensive beyond 600 V. Consequently,This possibility of increasing the operating voltage combined with the absence of harmonics in the injected current can allow the use of new electrical machines offering better volume power density, better mass power density, better maximum operating speed and better efficiency.

Claims

1. Battery (B1) comprising electrical energy storage cells and at least two main outputs (SPk) capable of delivering voltages of different types and intended to power different electrical equipment (MM, CP, B2) of a system (V), this battery comprising: i) conversion modules (MCj) each installed at the output of a group (Gj) of at least one cell and each comprising a first converter (CV1) of the DC-DC type and capable of converting a first direct voltage supplied by the output of said group (Gj) into a second predefined direct voltage, each of the conversion modules (MCj) comprising: - an inverter (ON) capable of converting said first direct voltage into a third predefined alternating voltage, and interconnection means (MCM) capable of connecting an output of said first converter (CV1) or an output of said inverter (ON) to an output of another group (Gj') or to one of said main outputs (SPk) according to a received instruction, - means of auxiliary control means (MCA) capable of generating control signals capable of placing said associated inverter (ON) in a state which is a function of a received instruction, each inverter (ON) being arranged in the form of an H-bridge, each conversion module (MCj) comprising control means (MP) capable of placing its H-bridge (ON) in a state which is a function of a control signal generated by said auxiliary control means (MCA), ii) main control means (MCP) capable of generating each instruction dedicated to each conversion module (MCj) according to a received definition of the type of voltage required to power at least one of said electrical equipment (MM, CP, B2), characterized in that each conversion module (MCj) comprises a second converter (CV2) of the DC-DC type and capable of converting said first DC voltage into a fourth predefined DC voltage intended to power said associated control means (MP).

2. Battery according to claim 1, characterized in that said auxiliary control means (MCA) associated with each group (Gj) are capable of determining a voltage at the terminals of the associated group (Gj) and a temperature within the associated group (Gj), and of estimating a current state of charge of the associated group (Gj).

3. Battery according to claim 1 or 2, characterized in that it comprises a multiplexed bus (BM) coupled to said main control means (MCP) and to each of said conversion modules (MCj), and in that each conversion module (MCj) comprises a controller (CB) coupled to said multiplexed bus (BM).

4. Battery according to one of claims 1 to 3, characterized in that it comprises three main outputs (SPk) capable of respectively delivering voltages of three different types.

5. Battery according to one of claims 1 to 4, characterized in that said voltage types are chosen from a very low direct voltage, typically 12 V, a low direct voltage, typically 450 V and a single-phase or three-phase alternating voltage.

6. System (V) comprising electrical equipment (MM, CP, B2), characterized in that it further comprises at least one battery (B1) according to one of the preceding claims, capable of powering said electrical equipment (MM, CP, B2).

7. System according to claim 6, characterized in that it constitutes a vehicle of the all-electric or hybrid type.