BATTERY ARCHITECTURE INTEGRATING A CUT-OFF SYSTEM

Abstract

Battery (1) comprising: - a set of cells (2), - a container (3) having two opposite ends and adapted to house this set of cells (2) between these two opposite ends, and comprising at one of these two ends a first electrical connection socket (P11) intended for a first electrical load, - a first current interruption system (S1) adapted to decouple the first socket (P11) from the set of cells (2), - at the second of these two ends a second electrical connection socket (P22) intended for a second electrical load, - a second current interruption system (S2) adapted to decouple the second socket (P22) from the set of cells (2), one of the cells (2) being physically interposed between the first and second current interruption systems (S1, S2). Figure 1.

Description

Title of the invention: BATTERY ARCHITECTURE INTEGRATING A CUT-OFF SYSTEM

[0001] Motor vehicles comprising one or more electric powertrains generally comprise a so-called low-voltage electrical network, powered by a so-called traction battery, with a voltage generally between 180V and 1000V, or between 350 and 800V, this network supplying, for example, the electric powertrains, in particular one or more electric motors.

[0002] Throughout the text of this document, the term electric powertrain will be understood to mean an assembly comprising at least one electric motor, and possibly electronics for controlling this motor, often referred to as an inverter.

[0003] Throughout the text of this document, the term “battery” will be understood to mean an assembly comprising several electrochemical cells, for example grouped into several modules. This battery possibly includes electrical or electronic means for managing the electrical energy of these modules. When there are several modules, they are grouped in a tray or casing and then form a battery pack, this battery pack often being designated by the English expression “battery pack”, this casing generally containing a mounting interface, and connection sockets for electrical loads including the electric powertrain(s).

[0004] Throughout the text of this document, the term "electric load" will be understood to mean both a consumer of electrical energy discharging the battery and a current generator recharging the battery, for example a reversible motor or an alternator.

[0005] Furthermore, the term electrochemical cell will be understood throughout the text of this document to mean cells generating current by chemical reaction, for example of the lithium-ion (or Li-ion) type, of the Ni-Mh, or Ni-Cd or lead type or even fuel cells.

[0006] This battery further comprises a junction box, housed in an enclosure of the casing or alternatively attached to this casing, this junction box providing an electrical cut-off interface between the cells and the sockets and comprising a set of switches, fuses, or any other cut-off means making it possible to electrically isolate the battery from one or all of its loads, these cut-off means being reversible like controlled switches, or irreversible like fuses. Thus the junction box makes it possible to isolate the sockets of the cells and / or modules in the event of problem, for example if a thermal runaway onset is diagnosed.

[0007] This junction box is centralized, that is to say that all the cut-off means are placed next to each other in the same area of ​​the battery. For example, this junction box is inserted between two modules or two cells, or located at one end of the battery.

[0008] The problem with this solution is that, in the case of several sockets for several loads, and in particular when the battery is inserted between two loads, having a centralized junction box leads to: - have long busbar lengths, and / or - electrically isolate the sockets using the junction box but keep two bus bars close to each other and maintaining a potential difference likely to create an additional internal short circuit to the battery in the event of thermal runaway.

[0009] It will be recalled here that the bus bars, well known to those skilled in the art, are generally rigid conductors, for example made of copper, connecting the polarities of the cells and / or modules to the sockets, or connecting the modules to each other. These bus bars are, in an equivalent but less compact manner, replaced by multi-strand conductors having flexibility. The cutting means of the junction box are suitable for electrically insulating these conductors or bars.

[0010] The aim of the invention is to remedy this problem. To this end, the invention relates to a battery comprising: - a set of cells comprising the cells and a first network of conductors connecting the cells together, for example in series or in parallel or a combination of the two, - a container having two opposite ends and suitable for housing this set of cells between these two opposite ends, and comprising at a first of these two ends a first electrical connection socket intended for a first electrical load, - a second network of conductors, configured to bring the current from this set of cells to the first socket, - a first power cut-off system capable of cutting off the second network to decouple the first socket from the set of cells, - at the second of these two ends a second electrical connection socket intended for a second electrical load, the second network of conductors being configured to bring the current from this set of cells to the second socket, - a second power cut-off system capable of cutting off the second network to decouple the second socket from the set of cells, one of the cells being physically interposed between the first and second power cut-off systems.

[0011] Thus, these two separate and distant cut-off systems can each be positioned as close as possible to the cells, and if these two cut-off systems cut the second network of conductors, all the conductors close to each other or which cross and which are not at the same potential (excluding cut-off) will be de-energized, and therefore without risk of short-circuit following thermal runaway of one or more cells. Indeed, these conductors are for example coated with an electrically insulating layer of plastic, a sheath for example, which can melt due to the rise in temperature caused by this thermal runaway, thus giving rise to an increased risk of short-circuit.

[0012] Furthermore, these two separate and distant cut-off systems can each be positioned as close as possible to the two sockets and thus avoid entire loops of conductors from the second network to reach one of the two sockets, or even both sockets, thus reducing the total lengths of conductors.

[0013] According to one embodiment of the invention, the set of cells is physically interposed between the first and second power cut-off systems.

[0014] According to one embodiment of the invention, the set of cells delivers a potential difference between a first terminal and a second terminal, the second network comprising: - a first conductor connecting the second terminal to the second cut-off system, - a second conductor connecting the second cut-off system to the second socket, - a third conductor connecting the second cut-off system to the first cut-off system, - a fourth conductor connecting the first cut-off system to the first socket, the second cut-off system being configured to isolate the first conductor from the second and third conductors, the first cut-off system being configured to isolate the third conductor from the fourth conductor.

[0015] According to one embodiment of the invention, the second network comprises: - a fifth conductor connecting the first terminal to the first cut-off system, - a sixth conductor connecting the first cut-off system to the first socket, - a seventh conductor connecting the first cut-off system to the second socket, the first cut-off system being configured to isolate the fifth conductor from the sixth and seventh conductors.

[0016] According to one embodiment of the invention, the second terminal delivers a positive potential, the first terminal a negative potential.

[0017] According to one embodiment of the invention, this battery comprises several modules grouping the cells, these modules being arranged in a line.

[0018] According to one embodiment of the invention, each of the two cut-off systems comprises a cut-off means from a set comprising switches configured to be controlled, protective fuses, pyrotechnic switches.

[0019] According to one embodiment of the invention, this battery comprises several first sockets and / or second sockets.

[0020] The invention also relates to a vehicle comprising: - a first electrical charge, and - a second electrical charge, and - a battery electrically coupled to these electrical charges, the battery being as previously described, the first socket being connected to the first electrical load, in particular an electrical motor driving a set of wheels of the vehicle, the second socket being connected to the second electrical load.

[0021] According to one embodiment of this vehicle, the first electrical load is an electric motor driving a wheel set of the vehicle, this vehicle further comprising an internal combustion engine capable of driving this same wheel set.

[0022] More specifically, the invention relates to a vehicle comprising: - a first electric motor machine, and - a second electric motor and / or generator, and - a battery electrically coupled to these electric machines, this battery being as previously described, the first socket being connected to the first electrical motor, in particular an electrical motor driving a rear axle of the vehicle, the second socket being connected to the second electrical machine, in particular an electrical motor driving a front axle of the vehicle.

[0023] According to one embodiment of the invention, this vehicle further comprises a combustion engine capable of driving the front axle in series or in parallel with the second electric machine.

[0024] Other features and advantages will appear on reading the following description of a particular, non-limiting embodiment of the invention, made with reference to the single [Fig.l] in which:

[0025] [Fig.l]: represents a diagram of an architecture of a battery according to the invention.

[0026] [Fig.l] discloses a battery 1 according to the invention, comprising: - a set of cells 2 comprising the cells 2 and a first network of conductors RI connecting the cells 2 together, for example here in series, but this could be in parallel or a series and parallel combination, - a tray 3 having two opposite ends and suitable for housing this set of cells 2 between these two opposite ends, and comprising at a first of these two ends a first electrical connection socket PI 1 intended for a first electrical load, - a second network Ci of conductors, configured to bring the current from this set of cells in series 2 to the first socket Pli, - a first current cut-off system SI capable of cutting the second network Ci to decouple the first socket PI 1 from the set of cells in series 2, - at the second of these two ends a second electrical connection socket P22 intended for a second electrical load, the second network of conductors Ci being configured to bring the current from this set of cells in series 2 to the second socket P22, - a second power cut-off system S2 suitable for cutting the second network Ci to decouple the second socket P22 from the set of cells in series 2, one of the cells 2 being physically interposed between the first and second power cut-off systems SI, S2.

[0027] As previously defined, the term “electric load” will be understood throughout the text of this document to mean both a consumer of electrical energy discharging the battery 1 and a current generator recharging the battery, for example a reversible motor or an alternator. Other examples are mentioned in this text and in accordance with this definition, for an automotive application: Electric motor, reversible or not, a battery charger, a charging cable, a charging terminal, a direct-direct current converter, an inverter, an electric air conditioning compressor, an electric heater for a passenger compartment, this list not being exhaustive.

[0028] It will be noted that [Fig.l] does not represent the cells 2, but four modules 2 grouping cells 2. This can be less than 4 modules, or even a single module 2, thus reducing the first network of conductors RI to a network internal to the single module 2 connecting the cells 2 together. This can also be more than 4 modules of course. These modules 2 are well known to those skilled in the art, and will not be described further in this text. It will just be noted that these modules 2 are not obligatory, the battery 1 can comprise cells 2, not grouped in a module 2, however having one or more sets of cells, each of these sets having cells 2 connected in series and / or in parallel. These four modules 2 are connected to each other in series, but could also be connected in parallel, thus creating a circuit of all the cells 2 in series and parallel.

[0029] The conductors RI, Ci are for example what the person skilled in the art calls bus bars, which are easy to integrate into the reduced enclosure of tray 3 due to their rigidity. These bus bars are, for example, coated with an electrically insulating layer which can unfortunately melt in the event of thermal runaway of a cell. However, if two of these conductors are close to each other and are at different potentials, once the insulating layer melts, a short circuit can occur, further aggravating the situation.

[0030] Regardless of whether or not this electrically insulating layer melts, it is useful to note that the gases emitted during thermal runaway of a cell are not only hot, but also include electrically conductive particles which can be deposited at any location in the enclosure of the tank 3, thus creating short circuits between two conductors which are not sheathed or whose sheath is melted. This risk is considerably reduced thanks to the invention.

[0031] This thermal runaway, mentioned several times, is also a phenomenon known to those skilled in the art, the origin of which generally comes from an internal short circuit in cell 2 causing a rise in temperature of the cell, thus increasing this internal short circuit, then this increase in temperature propagates to neighboring cells and so on.

[0032] Alternatively, these conductors are for example electrical cables, made of copper or aluminum, comprising several strands or strands, or single strands, and also coated with an electrically insulating outer layer which can also melt in the event of thermal runaway of the battery 1.

[0033] The first network of conductors RI thus comprises a set of conductors connecting a positive terminal of a first cell to a negative terminal of a second cell and so on, so as to connect in series all of the cells of the set of cells 2. For the sake of simplicity, these conductors all bear the same sign RI but are not necessarily all the same.

[0034] The second network Ci of conductors, the letter or index i being a number assigned to each of the conductors Cl, C2, C3 and so on, comprises all the conductors bringing the current from the set of cells 2 to the sockets P1, P12, P22, P21. Thus the second network Ci of conductors comprises: - a first set of conductors Cl, C2, C3, C4 subjected to a positive potential by convention, and - a second set of conductors C5, C6, C7 subjected to a negative potential by convention, the potential difference between these two sets being the potential difference at the terminals of the set of cells 2 in series, that is to say more precisely the voltage of battery 1 between 180 and 1000 V or between 350 and 800 V.

[0035] It will be noted that in [Fig. 1], the first set of conductors C1, C2, C3, C4 subjected to a positive potential is represented by dotted lines, while the second set of conductors C5, C6, C7 subjected to a negative potential is represented by a solid line.

[0036] By cutting of the second network Ci of conductors, we will understand an isolation by one of the cutting systems SI, S2 of at least one of the conductors C2, C4, C6, C7 directly connected to a terminal or pin of one of the sockets P1, P22, thus achieving the decoupling of a socket from the set of cells in series 2 according to the invention.

[0037] Throughout the text of this document, sockets will be understood to mean an electrical connection interface between the battery 1 and the electrical loads: male or female multi-pin sockets, or even a connection terminal block using bolted connections, or any other connection interface adapted to the current intensities consumed by the load according to the knowledge of those skilled in the art.

[0038] This socket is advantageously secured through a wall of the tray 3, but this is not obligatory, it can for example be internal to the enclosure of the tray 3, a power supply cable of the load passing through the partition of the tray 3 via a partition pass-through.

[0039] The set of cells 2 is for example physically interposed between the first and second power cut-off systems SI, S2.

[0040] For example, the power cut-off system is a box containing electrical cut-off means such as fuses or switches as will be described below, called a junction box, and which can, for example, directly support the sockets P1, P22, this junction box being able to be housed in the enclosure of the tray 3 or outside the tray 3. But this box can be fictitious, the cut-off system then being a simple grouping of cut-off means.

[0041] The set of cells 2 delivers a potential difference between a first terminal B1 and a second terminal B2, the second network Ci comprising: - a first conductor Cl connecting the second terminal B2 to the second cut-off system S2, - a second conductor C2 connecting the second cut-off system S2 to the second socket P22, - a third conductor C3 connecting the second cut-off system S2 to the first cut-off system SI, - a fourth conductor C4 connecting the first SI cut-off system to the first Pli socket, the second cutting system S2 being configured to isolate the first conductor Cl from the second and third conductors C2, C3, the first cutting system SI being configured to isolate the third conductor C3 from the fourth conductor C4.

[0042] The second network further comprises: - a fifth conductor C5 connecting the first terminal B1 to the first cut-off system SI, - a sixth conductor C6 connecting the first SI cut-off system to the first PI socket, - a seventh conductor C7 connecting the first cut-off system SI to the second socket P2, the first SI cut-off system being configured to isolate the fifth conductor C5 from the sixth and seventh conductors C6, C7.

[0043] The second terminal B2 delivers a positive potential, the first terminal B1 a negative potential.

[0044] It can be seen, with this architecture and as illustrated in [Fig.l], that the third conductor C3 and the seventh conductor C7 are close to each other, each being at a different potential. In the event of thermal runaway of the cells 2, or even in the event of shock or accident of a vehicle carrying this battery 1, the risk of short circuit between these two conductors is real. The second cut-off system S2 judiciously makes it possible to de-energize the third conductor C3 and therefore, no more short circuits are to be feared.

[0045] This battery comprises, for example, several modules 2 grouping the cells 2, these modules 2 being arranged in line.

[0046] Each of the two cut-off systems SI, S2 comprises a cut-off means Ki, Fi from a set comprising switches configured to be controlled, protective fuses, pyrotechnic switches.

[0047] For example and as illustrated in [Fig.l], the second cut-off system S2 comprises a single controlled switch K22, capable of electrically isolating the second conductor C2 (supplying the second socket P22) from the first conductor CL. This second cut-off system S2 could comprise several switches, each isolating a second second socket P21 from the first conductor Cl but, as illustrated, this same single controlled switch K22 is also capable of electrically isolating an eighth conductor C8 from the second network Ci of conductors, this eighth conductor C8 supplying current to the second second socket P21.

[0048] The first cut-off system SI is more complex, and comprises for example three controlled switches K12, K13, K14, a pyrotechnic switch K11, and three fuses F1, F2, F3. This first cut-off system SI is thus capable of cutting the second network Ci to decouple the first socket P11 but also a second first socket P12 as illustrated. The internal architecture of this first cut-off system SI does not provide essential characteristics to the invention, so one can refer directly to [Fig.l] for more details.

[0049] Thus this battery comprises for example several first sockets PI 1, P12 and / or second sockets P22, P21.

[0050] The pyrotechnic switch Kl 1 is known to those skilled in the art. It is distinguished from three controlled switches K12, K13, K14 because it is irreversible due to the fact that it destroys the conductor on which it is fixed on the one hand, and on the other hand its trigger signal is emitted by a more direct trigger system than that of the three controlled switches K12, K13, K14, and above all secure, that is to say including its own energy reserve (other than the so-called traction battery and the so-called service battery). This trigger system is for example an airbag trigger system, or even an overcurrent measurement system independent of a computer often called by the English acronym BMS which will be presented below.

[0051] This battery is advantageously applied to a vehicle comprising: - a first electric motor machine, and - a second electric motor and / or generator, and - the battery 1 as previously described and electrically coupled to these electrical machines, the first socket PI 1 being connected to the first electrical motor machine, in particular an electrical motor machine driving a rear axle of the vehicle, the second socket P22 being connected to the second electrical machine, in particular an electrical motor machine driving a front axle of the vehicle.

[0052] This vehicle comprises, for example, a combustion engine capable of driving the front axle in series or in parallel with the second electric machine.

[0053] For example, this vehicle is a motor vehicle further comprising: - a very low voltage electrical network, for example operating at a voltage between 12 and 24 V, or even between 10V and 30V, - a low voltage electrical network, for example operating at a voltage between 180V and 1000V or even between 350 and 800V, the second network Ci of conductors being part of this low voltage electrical network, - battery 1, traction, with a service voltage for example between 180V and 1000V or even between 350 and 800V, - a so-called service battery, with a service voltage generally of 12 to 24V or even 10 to 30V, - a calculator, - a direct current to direct current converter.

[0054] The very low voltage electrical network is powered by the so-called service battery, this very low voltage electrical network powering the computer and for example one or more secondary computers of the vehicle as well as accessories. This very low voltage electrical network also powers communication networks between the vehicle computers, sensors or probes, control actuators such as relays or micromotors operating under the voltage of this electrical network very low voltage, or even the controlled switches K22, K12, K13, K14 according to the invention.

[0055] The low-voltage electrical network is powered by the traction battery 1, and is configured to power, for example, the electric powertrain(s), in particular an electric motor, via the first and / or second sockets P11, P12, P22, P21.

[0056] The very low voltage electrical network and the low voltage electrical network are for example connected to each other through the direct current - direct current converter, the traction battery 1 then being able to recharge the service battery via this converter. But this connection and this converter are not obligatory, the service battery being able to be recharged by other means, such as for example an alternator of a combustion engine if this vehicle is equipped with one, this combustion engine being able to participate or not in the drive of the vehicle. This converter is for example connected to the second second socket P21 or the second first socket P12 and is considered, according to the invention, as an electrical load.

[0057] This calculator, often referred to by the English acronym BMS for “battery management System”, comprises the means of acquisition, processing by software instructions stored in a memory as well as the control means required for the implementation of a method for managing the cells or modules 2, for example to establish the state of charge of the battery 1, the state of health, manage the balancing between the cells, determine the start of thermal runaway of a cell, or control the controllable switches K22, K12, K13, K14, this list not being exhaustive. This calculator is for example integrated into the battery 1.

[0058] This calculator can comprise several secondary calculators, for example one for each module 2.

[0059] It will be noted, of course, that this vehicle may include an on-board charger, coupled to the low-voltage electrical network or directly coupled to the traction battery 1 via, for example, one of the sockets, in particular the second first socket P21. Alternatively, this charger may be integrated into the traction battery 1, for example; it is then a deployable charging cable that will directly connect one of the sockets, and in particular the second first socket P21, to a land-based electrical network, for example via a charging station. This charger may, for example, include a charging calculator for managing the on-board charger according to different charging modes known to those skilled in the art, conventionally referred to as mode 1, mode 2, mode 3 or even mode 4.In general, the vehicle includes an external socket through which the land-based electrical network can be connected to the on-board charger or directly to the traction battery 1 via the charging cable, for example removable.

[0060] This traction battery 1 has a much greater energy storage capacity than the service battery, and is regularly discharged when the vehicle driven by the electric powertrain(s) is running.

Claims

Claims

1. Battery (1) comprising: - a set of cells (2) comprising the cells and a first network of conductors (RI) connecting the cells (2) together, in particular in series, - a tray (3) having two opposite ends and suitable for housing this set of cells (2) between these two opposite ends, and comprising at a first of these two ends a first electrical connection socket (PI 1) intended for a first electrical load, - a second network (Ci) of conductors, configured to bring the current from this set of cells (2) to the first socket (Pli), - a first current cut-off system (SI) suitable for cutting the second network (Ci) to decouple the first socket (PI 1) from the set of cells (2), characterized in that it further comprises: - at the second of these two ends a second electrical connection socket (P22) intended for a second electrical load,the second network of conductors (Ci) being configured to bring the current from this set of cells (2) to the second socket (P22), - a second current cut-off system (S2) capable of cutting the second network (Ci) to decouple the second socket (P22) from the set of cells (2), one of the cells (2) being physically interposed between the first and the second current cut-off system (SI, S2).,

2. Battery according to claim 1, the set of cells (2) being physically interposed between the first and second current cut-off systems (S1, S2).

3. Battery according to one of the preceding claims, the set of cells (2) delivering a potential difference between a first terminal (B1) and a second terminal (B2), the second network (Ci) comprising: - a first conductor (Cl) connecting the second terminal (B2) to the second cut-off system (S2), - a second conductor (C2) connecting the second cut-off system (S2) to the second socket (P22), - a third conductor (C3) connecting the second cut-off system (S2) to the first cut-off system (SI), - a fourth conductor (C4) connecting the first cut-off system (SI) to the first socket (Pli), the second cut-off system (S2) being configured to isolate the first conductor (Cl) from the second and third conductors (C2, C3), the first cut-off system (SI) being configured to isolate the third conductor (C3) from the fourth conductor (C4).

4. Battery according to claim 3, the second network comprising: - a fifth conductor (C5) connecting the first terminal (Bl) to the first cut-off system (SI), - a sixth conductor (C6) connecting the first cut-off system (SI) to the first socket (PI), - a seventh conductor (C7) connecting the first cut-off system (SI) to the second socket (P2), the first cut-off system (SI) being configured to isolate the Fifth conductor (C5) from the sixth and seventh conductors (C6, C7).

5. Battery according to claim 3 or 4, the second terminal (B2) delivering a positive potential, the first terminal (B1) a negative potential.

6. Battery according to one of the preceding claims, comprising several modules (2) grouping the cells (2), these modules (2) being arranged in line.

7. Battery according to one of the preceding claims, each of the two cut-off systems (SI, S2) comprising a cut-off means (Ki, Fi) from a set comprising switches configured to be controlled, protective fuses, pyrotechnic switches.

8. Battery according to one of the preceding claims, comprising several first sockets (P11, P12) and / or second sockets (P22, P21).

9. Vehicle comprising: - a first electrical load, and - a second electrical load, and - a battery (1) electrically coupled to these electrical loads, characterized in that the battery conforms to one of the preceding claims, the first socket (Pli) being connected to the first electrical load, in particular an electrical motor driving a set of wheels of the vehicle, the second socket (P22) being connected to the second electrical load.

10. A vehicle according to claim 9, the first electrical charge being an electric motor driving a wheel set of the vehicle, this vehicle further comprising an internal combustion engine capable of driving this same wheel set.

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