Cellular battery with one or more non-disruptive switching devices, for a battery assembly of a system

Abstract

The invention relates to a battery (BC) comprising M modules (MC), each comprising at least one electrical energy storage cell (CE), which modules are mounted in series with a switching device (DC) having open and closed states, and are coupled to analysis devices (DA) determining current values of quantities representative of the cells (CE) and communicating with one another via a communication line (LC) comprising isolation capacitors, some of which are coupled to terminals of the switching device (DC). This battery (BC) further comprises a resistive element (ER) mounted in parallel with the switching device (DC) in order to minimise the voltage, across the isolation capacitors coupled to the terminals of the switching device (DC), to prevent communication over the communication line (LC) from being interrupted when the switching device (DC) is in its open state.

Description

DESCRIPTION TITLE: CELLULAR BATTERY WITH NON-INTERFERING SWITCHING DEVICE(S), FOR A BATTERY ASSEMBLY OF A SYSTEM The present invention claims priority from French application No. 2305481 filed on 01.06.2023, the content of which (text, drawings and claims) is incorporated herein by reference. Technical field of the invention

[0001] The invention relates to cellular batteries comprising at least one anti-thermal runaway switching device and intended to be part of a battery assembly of a system. State of the art

[0002] In many systems, such as vehicles (possibly automotive), cellular batteries are used as part of (cellular) modules connected in series. Here, the term "cellular battery" means a battery comprising M modules, each comprising at least one electrical energy storage cell, and connected in series with at least one switching device (with open and closed states), with M > 2.

[0003] For example, in a vehicle the cellular battery is generally coupled to at least one electric motor of a powertrain (or GMP) in order to supply it with current so that it produces engine torque, and possibly to be supplied with recharging current by this electric motor. It will be noted that in such an example, the cellular battery constitutes a main (or traction) battery. It will also be noted that in such a cellular battery the electrical energy storage cells may possibly be electrochemical (for example of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type).

[0004] Sometimes, a cellular battery is part of a battery assembly (or "pack") which also includes a battery case comprising analysis devices capable of determining current values ​​of quantities representative of the cells and communicating with each other via a communication line comprising isolation capacitors, and a battery computer coupled to this communication line to receive the determined current values ​​and responsible for controlling the operation of this cellular battery according to these received values.

[0005] Since the (each) switching device of a cellular battery is connected in series between two cellular modules, it makes it possible to at least delay the thermal runaway of its cellular battery when it is placed in its open state by the battery computer. This is particularly useful for the safety of the vehicle and its passengers and the environment of this vehicle.

[0006] However, due to its series connection between two cell modules, a switching device becomes coupled to some of the isolation capacitors of the communication line that supplies the battery computer with determined current values. Therefore, when a switching device is placed in its open state, this causes a charging of the isolation capacitors that are coupled to its terminals, which causes them to lose a significant part of their capacitive effect. As a result, the communication between the two analysis devices that are coupled via these charged isolation capacitors is impacted and the "receiving" analysis device considers that there is a communication interruption on the communication line.

[0007] It will be understood that such an interruption prevents the battery computer, when starting its system (for example a vehicle), from initializing communication with the analysis devices, to receive the current values ​​of quantities representative of the cells. In the absence of this reception, the battery computer is not able to determine whether it is possible to place each analysis device in its closed state, and therefore it generates an alert message signaling a failure, and prevents the use of the cellular battery (which prevents any movement of the vehicle when its GMP is all electric).

[0008] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0009] It proposes in particular for this purpose a battery, intended to be part of a system, and comprising M modules, on the one hand, each comprising at least one electrical energy storage cell, on the other hand, mounted in series with at least one switching device having open and closed states, with M > 2, and, on the other hand, capable of being coupled to analysis devices capable of determining current values ​​of quantities representative of these cells and communicating with each other via a communication line comprising isolation capacitors, some of which are capable of being coupled to terminals of the (one) switching device.

[0010] This battery is characterized by the fact that it also comprises at least one resistive element mounted in parallel with the (one) switching device in order to minimize a voltage, seen by the isolation capacitors which are coupled to the terminals of this switching device, to avoid an interruption of communication on the communication line when this switching device is in its open state.

[0011] Thanks to the invention, the switching device is now "non-disruptive" for the communication line when it is placed in its open state, since it can no longer induce any interruption of communication on this communication line.

[0012] The battery according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0013] - the (each) resistive element may have a first resistance which is a function of a second equivalent resistance of the communication line with the analysis devices;

[0014] - in the presence of the first option, the first resistance can be between 90% of the second equivalent resistance and 110% of the second equivalent resistance;

[0015] - in the presence of the last sub-option, the first resistance can be between 600 kQ and 1 MQ when the second equivalent resistance is between 600 kQ and 1 MQ;

[0016] - the (each) resistive element may comprise at least one resistor;

[0017] - the (each) switching device may be a relay;

[0018] - the cells can be of the electrochemical type.

[0019] The invention also provides a battery assembly comprising:

[0020] - a battery box comprising analysis devices capable of determining current values ​​of quantities representative of cells and communicating with each other via a communication line comprising isolation capacitors,

[0021] - a battery calculator coupled to this communication line to receive the current values ​​determined, and

[0022] - a battery of the type presented above and having its modules coupled to the analysis devices and each switching device coupled to some of the isolation capacitors.

[0023] The invention also proposes a system comprising at least one battery assembly of the type presented above.

[0024] For example, this system may constitute a vehicle. In this case, the vehicle may include a powertrain (or GMP) comprising at least one electric motor coupled to the battery assembly. Brief description of the figures

[0025] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0026] [Fig. 1] schematically and functionally illustrates an exemplary embodiment of a vehicle comprising an exemplary embodiment of a battery assembly according to the invention and a GMP transmission chain with an electric motor coupled to this battery assembly, and

[0027] [Fig. 2] schematically and functionally illustrates an electrical diagram equivalent to the battery assembly of Figure 1. Detailed description of the invention

[0028] The invention aims in particular to propose a battery BC intended to be part of a battery assembly EB, itself intended to equip a system S and also comprising a battery box BB, and not causing interruption of the communication line LC of the battery box BB when the (one) DC switching device that it comprises is in its open state.

[0029] In the following, it is considered, by way of non-limiting example, that the system S is a motor vehicle, such as for example a car, as illustrated in Figure 1. But the invention is not limited to this type of system. It in fact relates to any type of system comprising at least one battery assembly with a cellular battery. Thus, it relates to vehicles (land, sea (or river), and air), buildings, and installations (possibly industrial).

[0030] Furthermore, it is considered in the following, by way of non-limiting example, that the vehicle S comprises a transmission chain with a powertrain (or GMP) of the all-electric type (and therefore whose drive is provided exclusively by at least one machine MME electric motor). But the GMP could be of the hybrid type (thermal and electric).

[0031] Figure 1 schematically shows a system S (here a vehicle) comprising an electric GMP transmission chain (and therefore an electric motor MME), a supervision computer CS, an on-board network RB, a service battery BS, a battery assembly EB comprising a cellular battery BC according to the invention and a battery box BB, and an electrical power supply system.

[0032] The power supply system comprises a main electrical circuit connected to a power connector CR and a charger CH comprising a charger computer CA as well as here a converter CV, as well as to the electric motor MME.

[0033] The on-board network RB is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume electrical energy are coupled.

[0034] The service battery BS is responsible for supplying electrical energy to the on-board network RB, in addition to that supplied by the CV converter powered by the cellular battery BC via the main electrical circuit, and sometimes instead of this CV converter. For example, this service battery BS can be arranged in the form of a very low voltage type battery (typically 12 V, 24 V or 48 V). It is rechargeable at least by the CV converter. In the following, as a non-limiting example, it is considered that the service battery BS is of the 12 V Lithium-ion type.

[0035] The main electrical circuit (or "high voltage") is more precisely connected, on the one hand, to the cellular battery BC via the battery box BB, and, on the other hand, to electronic equipment, such as for example the converter CV and the electric motor MME. It also allows the recharging of the cellular battery BC by an external power source and temporarily coupled to the power connector CR of the vehicle S. In the example illustrated non-limitingly in figure 1 the main electrical circuit allows to recharge the cellular battery BC not only in direct current (or mode 4), but also in alternating current (or mode 2 or 3), under the control of the charger calculator CA (of the charger CH) and battery calculator CB (of the battery box BB). But in variant embodiments not illustrated, the main electrical circuit could only allow recharges in direct current (or mode 4) or only recharges in alternating current (or mode 2 or 3).

[0036] The transmission chain has a GMP which is, here, purely electric and therefore which comprises, in particular, an electric motor MME, a motor shaft AM, and a transmission shaft AT. Here, the term "electric motor" means an electric machine arranged so as to provide torque to move the vehicle S when it is supplied with electrical energy, as well as possibly to recover torque in the transmission chain.

[0037] The operation of the transmission chain (and therefore of the GMP) is supervised by a CS supervision computer.

[0038] The electric motor MME (here an electric motor) is here coupled to the cell battery BC via the main electrical circuit and the battery box BB, in order to be supplied with electrical energy, as well as possibly to supply this cell battery BC with electrical energy, for example during a regenerative braking phase.

[0039] Furthermore, this electric motor MME is coupled to the motor shaft AM, to provide it with torque by rotating it. This motor shaft AM is here coupled to a reducer RD which is also coupled to the transmission shaft AT, itself coupled to a first train T1 (here of wheels), preferably via a differential DV.

[0040] This first train T1 is here located in the front part PW of the vehicle S. But in a variant this first train T1 could be the one which is here referenced T2 and which is located in the rear PRV part of the vehicle S.

[0041] The CV converter can also be responsible, during the driving phases of the vehicle S, for converting part of the electric current stored in the cellular battery BC to supply converted electric current to the on-board network RB and the service battery BS (to recharge it).

[0042] It will be noted, as illustrated non-limitingly in Figure 1 and as indicated above, that the CV converter can be part of the CH charger which also includes the CA charger calculator responsible, at least, for controlling the recharges of the BC cellular battery.

[0043] The BC cell battery here powers the electric motor MME, it constitutes a main (or traction) battery. It (BC) comprises M MC modules each comprising at least one CE cell for storing electrical energy, and connected in series with at least one DC switching device having open and closed states, with M > 2.

[0044] The (each) DC switching device allows to prevent the flow of current in its cell battery BC when it is placed in its open state by the battery computer CB. In this case, it (DC) allows to at least delay the thermal runaway of its cell battery BC.

[0045] It will be noted that in the example illustrated non-limitingly in Figure 1, the cellular battery BC only comprises one DC switching device connected in series between two cellular modules MC. But the cellular battery BC could comprise several (at least two) DC switching devices.

[0046] For example, the (each) DC switching device can be a relay (preferably static (and therefore fully electronic)). But this is not mandatory, the important thing being that it includes an open (or non-passing) state and a closed (or passing) state.

[0047] It will also be noted that in the example illustrated non-limitingly in Figure 1, the cellular battery BC comprises six (M = 6) cellular modules MC. But the number of cellular modules MC can take any value greater than or equal to two.

[0048] It will also be noted that in the example illustrated non-limitingly in Figure 1, each MC cell module comprises three CE cells (for electrical energy storage). But the number of CE cells in each MC cell module can take any value greater than or equal to one.

[0049] For example, CE cells can be electrochemical type (e.g. lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type). Also for example, BC cell battery can be low voltage type (typically 450 V for illustration). But it could be medium voltage or high voltage type.

[0050] Furthermore, the battery box BB also includes analysis devices DA which are capable of determining current values ​​of quantities representative of the cells CE and which communicate with each other via a communication line LC comprising isolation capacitors (not shown). This communication line LC is coupled to the battery computer CB so that it can receive these determined current values ​​and control the operation of the cell battery BC according to these determined and received current values.

[0051] For example, the quantities, the values ​​of which are determined by a DA analysis device, can be cell temperatures and voltages.

[0052] It will be noted that in the example illustrated non-limitingly in Figure 1 each DA analysis device is associated and coupled to two MC cellular modules. But the number of MC cellular modules to which a DA analysis device can be coupled can take any value greater than or equal to one.

[0053] It should also be noted that some of the isolation capacitors are coupled across the terminals of the (a) DC switching device. This is more specifically the case for those associated with the MC cellular module coupled to one of the terminals of the (a) DC switching device.

[0054] It will also be noted that in the example illustrated non-limitingly in Figure 1, the vehicle S also comprises a distribution box BD to which the service battery BS, the converter CV and the on-board network RB are coupled. This distribution box BD is responsible for distributing in the on-board network RB the electrical energy stored in the service battery BS or produced by the converter CV, for the supply of the electrical components (or equipment) coupled to the on-board network RB according to power supply requests received (in particular from the supervision computer CS of the GMP).

[0055] As illustrated in Figure 1, the cell battery BC also includes at least one resistive element ER which is connected in parallel with the (one) DC switching device in order to minimize the voltage seen by the isolation capacitors which are coupled across the terminals of this DC switching device. This minimization is intended to avoid a communication interruption on the communication line LC when the DC switching device is placed in its open state.

[0056] It will be understood in fact, by observing the equivalent electrical diagram of the battery assembly EB illustrated in figure 2, that the installation of a resistive element ER in parallel with the terminals of a DC switching device amounts to defining a divider bridge which minimizes the voltage seen by the insulation capacitors concerned, and therefore makes it possible to prevent the latter from charging when the DC switching device is placed in its open state. From this In fact, the information bits, which are communicated via the LC communication line by propagation from one DA analysis device to the next DA analysis device, are at a sufficiently high level to remain interpretable, which means that there is no communication interruption on the LC communication line when the DC switching device is placed in its open state. In other words, the DC switching device is now non-disruptive to the LC communication line when it is placed in its open state.

[0057] In the equivalent electrical diagram of the EB battery pack shown in Figure 2:

[0058] - the first resistance r1 represents the resistance of the resistive element ER,

[0059] - the second resistance r2 represents the equivalent resistance of the LC communication line with the DA analysis devices,

[0060] - the reference v1 represents the first voltage across the terminals of the DC switching device and therefore of the resistive element ER,

[0061] - the reference v2 represents the second voltage created by the MC cellular modules which are located downstream of the DC switching device and therefore of the resistive element ER,

[0062] - the reference v3 represents the third voltage created by the MC cellular modules which are located upstream of the DC switching device and therefore of the resistive element ER, and

[0063] - the reference v4 represents the fourth voltage at the terminals of the cellular battery BC, and which is equal to v2 + v3 when we neglect the first voltage v1.

[0064] In the presence of such an equivalent electrical diagram, the first voltage v1 is given by the equation v1 = [r1 / (r1 + r2)]*v4, and the second voltage v2 is given by the equation v2 = [r2 / (r1 + r2)]*v4.

[0065] It is important to note that the divider bridge thus formed is sized so that it is always possible to achieve diagnostics of the DC switching device concerned (it must in fact be possible to determine by comparing the voltage measurements taken upstream and downstream of the DC switching device whether the latter (DC) is in its open state or its closed state.

[0066] For this purpose, the (each) resistive element ER may have a first resistance r1 which is a function of the second equivalent resistance r2 of the communication line LC with the analysis devices DA. In this case, the first resistance r1 may, for example, be between 90% of the second equivalent resistance r2 and 110% of the second equivalent resistance r2.

[0067] For example, the first resistance r1 may be between 600 kΩ and 1 MΩ when the second equivalent resistance r2 is also between 600 kΩ and 1 MΩ. As an illustrative example, the first resistance r1 may be equal to 800 kΩ when the second equivalent resistance r2 is equal to 800 kΩ. These values ​​of the first r1 and second r2 resistances are particularly well suited to the case where the fourth voltage v4 across the terminals of the cellular battery BC is approximately 400 V.

[0068] It can be shown that, in the presence of the values ​​(r1, r2 and v4) mentioned in the previous paragraph and isolation capacitors having a capacity of 6.8 nF, the parallel connection of an ER resistive element and a DC switching device results in a reduction of 109 V in the voltage seen by the isolation capacitors concerned. Consequently, the loss of capacity caused by this reduction is only 10%, which corresponds to a reduced capacity equal to 6.12 nF (instead of 6.8 nF), almost three times the minimum required (2.2 nF) for the information bits communicated by the LC communication line to be at a level high enough to remain interpretable.

[0069] Also for example, the (each) resistive element ER may comprise at least one resistor. Thus, it may comprise a resistor or several resistors (at least two) connected in series and / or in parallel or it can be an “RP” type filter or an “RC” type device, for example.

Claims

CLAIMS

1. Battery (BC) comprising M modules (MC) i) each comprising at least one cell (CE) for storing electrical energy, ii) mounted in series with at least one switching device (DC) having open and closed states, with M > 2, and ll) suitable for being coupled to analysis devices (DA) suitable for determining current values of quantities representative of said cells (CE) and communicating with each other via a communication line (LC) comprising isolation capacitors, some of which are suitable for being coupled to terminals of said switching device (DC), characterized in that it further comprises at least one resistive element (ER) mounted in parallel with said switching device (DC) in order to minimize a voltage, seen by said isolation capacitors coupled to said terminals of the switching device (DC),to avoid an interruption of communication on said communication line (LC) when said switching device (DC) is in its open state.,

2. Battery according to claim 1, characterized in that said resistive element (ER) has a first resistance depending on a second equivalent resistance of said communication line (LC) with said analysis devices (DA).

3. Battery according to claim 2, characterized in that said first resistance is between 90% of said second equivalent resistance and 110% of said second equivalent resistance.

4. Battery according to claim 3, characterized in that said first resistance is between 600 kΩ and 1 MΩ when said second equivalent resistance is between 600 kΩ and 1 MΩ.

5. Battery according to one of claims 1 to 4, characterized in that said resistive element (ER) comprises at least one resistor.

6. Battery according to one of claims 1 to 5, characterized in that said switching device (DC) is a relay.

7. Battery according to one of claims 1 to 6, characterized in that said cells (CE) are of the electrochemical type.

8. Battery assembly (EB) comprising a battery housing (BB) comprising i) analysis devices (DA) capable of determining current values of quantities representative of cells (CE) and communicating with each other via a communication line (LC) comprising isolation capacitors, and ii) a battery computer (CB) coupled to said communication line (LC) to receive said determined current values, characterized in that it further comprises a battery (BC) according to one of the preceding claims, having its modules (MC) coupled to said analysis devices (DA) and each switching device (DC) coupled to some of said isolation capacitors.

9. System (S), characterized in that it comprises at least one battery assembly (EB) according to claim 8.

10. System according to claim 9, characterized in that it constitutes a vehicle.

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