MONITORING A CELLULAR BATTERY FOR INTERNAL SHORT CIRCUIT DETECTION

Abstract

A monitoring method makes it possible to monitor a cellular battery equipping a system and comprising at least one module comprising at least two electrical energy storage cells, coupled between neighbors and each subject to successive voltage measurements at their terminals. This method comprises a step (10-40) in which, when no current flows in the cellular battery, information representative of a temporal variation of its voltage measurements is determined for each cell, and, when information determined for two neighboring cells represents temporal variations behaving in substantially opposite ways, an alarm is generated capable of signaling a short circuit in the cellular battery. Figure 3

Description

Title of the invention: MONITORING OF A CELLULAR BATTERY FOR SHORT CIRCUIT DETECTION INTERNAL Technical field of the invention

[0001] The invention relates to cellular batteries comprising modules of at least two electrical energy storage cells, and more specifically to the monitoring within such vehicles of the operation of the cellular battery to detect an internal short circuit. State of the art

[0002] Certain systems, such as for example certain vehicles (possibly automobiles), comprise a cellular battery, comprising at least one module comprising at least two cells capable of storing electrical energy, and in which an electric current (discharge or recharge) can circulate.

[0003] It will be noted that in a vehicle such a cellular battery is generally coupled to at least one electric motor of the powertrain (or GMP), in order to supply it with electrical energy so that it can produce engine torque to move this vehicle. It will be understood that during such a supply the cellular battery discharges. Such a cellular battery is generally called "main" (or "traction" or even "power").

[0004] As is known to those skilled in the art, it may happen that a (cellular) module is subject to an internal short circuit. This may for example result from a false internal contact or an unexpected internal contact (for example between two inter-cell connections) or from the presence of conductive liquid in the protective casing (or envelope) housing the modules and forming part, with the cellular battery, of what is generally called a battery assembly (or "pack"). This may in particular occur following a significant impact suffered by the protective casing and causing it to be punctured, or from the disengagement of a cooling circuit hose present in the protective casing.

[0005] These internal short circuits release stored energy in the form of thermal energy, which causes an increase in the internal temperature that can lead to thermal runaway (or "thermal runaway") which can then trigger a fire. In addition, when the short circuit results from the presence of a conductive liquid, it causes an electrolysis reaction of the liquid crossed by the current which releases hydrogen and oxygen which can potentially cause an explosion.

[0006] In order to attempt to detect short circuits linked to the sole presence of a conductive liquid, it has been proposed to install a dedicated liquid level sensor on the bottom of the protective casing or to use the information on loss of insulation of the cellular battery (developed by the computer associated with the latter) when an interface device associated with the protective casing is in its open state. The first solution (with a dedicated liquid level sensor) proves to be relatively expensive, complicates the arrangement in the battery assembly and the liquid level sensor may be subject to malfunctions. The second solution (consisting of using the information on loss of insulation) is not very reliable. Indeed, the loss of insulation can indeed result from the presence of a liquid, but also from the presence of humidity or slight, non-serious electrolyte leaks.Therefore, in practice, this information is not used to issue an alert due to the high probability of a false alert, and the vehicle is simply requested to stop immediately.

[0007] It has also been proposed to detect the presence of an internal short circuit rather than the presence of liquid by means of a current sensor implanted in the protective housing. However, such a solution is not very reliable because the current loop generated by the short circuit does not necessarily pass through the current sensor. In addition, the current sensor may be subject to malfunctions.

[0008] It has also been proposed to detect the presence of dihydrogen (or H2) in the protective housing by means of a dedicated sensor. But this proves to be relatively expensive, complicates the arrangement in the battery assembly and the dihydrogen sensor can be subject to malfunctions.

[0009] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0010] It proposes in particular for this purpose a monitoring method intended to enable monitoring of a cellular battery suitable for equipping a system and comprising at least one module comprising at least two electrical energy storage cells, coupled together and each subject to successive voltage measurements at their terminals.

[0011] This monitoring method is characterized by the fact that it comprises a step in which, when no current flows in the cellular battery, information is determined for each cell which is representative of a temporal variation of its voltage measurements, and, when information determined for two neighboring cells represents temporal variations behaving in substantially opposite ways, an alarm is generated capable of signaling a short circuit in the cellular battery.

[0012] Thanks to the invention, the safety of users of the system is significantly and reliably improved, even though no sensor dedicated to detecting internal short circuits has been used.

[0013] The monitoring method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0014] - in its step, we can determine for each cell information which is re presenting a temporal variation of its voltage measurements over a chosen and sliding time interval;

[0015] - in its step, we can determine for each cell an average voltage at from its successive voltage measurements, and the alarm can be generated when the information, determined for two neighboring cells, represents temporal variations in relation to their respective determined average voltages behaving in opposite ways;

[0016] - in the presence of the first and second options, in its step, it is possible to determine for each cell the average voltage from its successive voltage measurements in the chosen time interval;

[0017] - in the presence of the second option, in its step, we can determine for each cell a difference between a last voltage measurement and the average voltage, then a cumulative difference equal to a sum of a previous cumulative difference and the determined difference, then, when a determined cumulative difference is lower than a negative threshold, we can associate with the cell concerned a so-called negative information, while when a determined cumulative difference is higher than a positive threshold, we can associate with the cell concerned a so-called positive information, and, when two neighboring cells are associated respectively with negative information and positive information, we can generate the alarm.

[0018] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a monitoring method of the type presented above, in a system comprising a cellular battery comprising at least one module comprising at least two electrical energy storage cells, coupled between neighbors and each subject to successive voltage measurements at their terminals, to monitor this cellular battery.

[0019] The invention also proposes a monitoring device intended to be part of a system comprising a cellular battery comprising at least one module comprising at least two electrical energy storage cells, coupled between neighbors and each subject to successive voltage measurements at their terminals.

[0020] This monitoring device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting of, when no current flows in the cellular battery, to determine for each cell information representative of a temporal variation of its voltage measurements, and, when information determined for two neighboring cells represents temporal variations behaving in substantially opposite ways, to trigger generation of an alarm capable of signaling a short circuit in the cellular battery.

[0021] The invention also proposes a system comprising, on the one hand, a cellular battery comprising at least one module comprising at least two electrical energy storage cells, coupled together and each subject to successive voltage measurements at their terminals, and, on the other hand, a monitoring device of the type presented above.

[0022] For example, this system may constitute a vehicle, possibly of the automobile type. In this case, the vehicle may also comprise at least one electric motor capable of being supplied with electrical energy by the cellular battery. Brief description of the figures

[0023] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0024] [Fig. 1] schematically and functionally illustrates an exemplary embodiment of a vehicle comprising a monitoring device according to the invention and a GMP transmission chain with an electric motor associated with a battery assembly comprising a cellular battery and a battery box with an interface device and battery calculator,

[0025] [Fig.2] schematically and functionally illustrates an exemplary embodiment of a battery calculator comprising an exemplary embodiment of a monitoring device according to the invention,

[0026] [Fig.3] schematically illustrates an example of an algorithm implementing a monitoring method according to the invention, and

[0027] [Fig.4] schematically illustrates within a diagram an example of temporal variations (t (in seconds)), behaving in substantially opposite ways, of the respective cell voltages (uc2 and uc3) of second and third neighboring cells of the same module. Detailed description of the invention

[0028] The invention aims in particular to propose a monitoring method, and an associated monitoring device DS, intended to enable the monitoring of the operation of a cellular battery BC, equipping a system S and comprising at least one module MC comprising at least two energy storage cells CEn electrical, to detect an internal short circuit in such an MC module.

[0029] In the following, it is considered, by way of non-limiting example, that the system S is a vehicle of the automobile type, such as for example a car (as illustrated in [Fig.l]). But the invention is not limited to this type of system. Indeed, the cellular batteries BC can be part of any system, and in particular vehicles (land, sea (or river), or air), electronic devices (possibly household appliances), mobile machines (including those which provide a lifting function), installations (possibly industrial), and buildings, for example.

[0030] Furthermore, it is considered in the following, by way of non-limiting example, that the system S (here a vehicle) 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 electric motor MME). But the GMP could be of the hybrid type (thermal and electric).

[0031] [Fig.l] schematically shows a system S (here a vehicle) comprising a monitoring device DS, an electrical power supply system, a transmission chain with electric GMP (here) (and therefore with electric motor MME), a supervision computer CS, an on-board network RB, a service battery BS, a converter CV, and a battery assembly EB comprising a cellular battery BC and a battery box BB comprising an interface device DI and a battery computer CB.

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

[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. It is considered in the following, by way of non-limiting example, that the service battery BS is of the 12 V Lithium-ion type.

[0035] The main (or "high voltage") electrical circuit is more precisely connected, on the one hand, to the cellular battery BC via the battery box BB (and more precisely its interface device DI), and, on the other hand, to electronic equipment, such as for example the CV converter and the MME electric motor. It also allows the recharging of the cellular battery BC by an external power source and for example temporarily coupled to the possible CR power connector. In the example illustrated non-limitingly in [Fig.l] the main electrical circuit allows the recharging of 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 alternative embodiments not illustrated, the main electrical circuit could only allow recharging in direct current (or mode 4) or only recharging 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 cellular battery BC via the main electrical circuit and the battery box BB (and more precisely its interface device DI), in order to be supplied with electrical energy, as well as possibly to supply this cellular 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 rotational drive. 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 DF.

[0040] This first train T1 is here located in the front part PVV 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 part PRV 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 electrical energy stored in the cellular battery BC to supply the on-board network RB and the service battery BS (to recharge it) with converted electrical current.

[0042] It will be noted, as illustrated non-limitingly in [Fig.l] 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 battery. BC cell phone.

[0043] The cellular battery BC here supplies the electric motor MME, it constitutes a main battery (or traction or power). It (BC) comprises at least one module MC comprising at least two cells CEn each capable of storing electrical energy. As illustrated in [Fig.l], the cells CEn are coupled between neighbors (CEn-1 and CEn) or (CEn and CEn+1) via inter-cell conductive physical connections. In operation (discharge or recharge), a current (discharge or recharge) flows in the cellular battery BC.

[0044] The interface device DI has, for example, an open (or non-conducting) state in which it prohibits the flow of the aforementioned current, and a closed (or conducting) state in which it authorizes the flow of the aforementioned current. It is therefore arranged so as to isolate, if necessary, the cellular battery BC at least from the entirety of the main electrical circuit. It notably comprises contactors (or switches or relays), possibly based on MOSFET(s), and protective fuses.

[0045] Each cell CEn is subject to successive measurements of the cell voltage at its terminals ucn. For example, these measurements can be carried out periodically (the period can be between 50 milliseconds and 100 milliseconds, for example).

[0046] For example, CEn cells can be electrochemical. In this case, they can be of the lithium-ion (or Li-ion) or Ni-Mh or Ni-Cd type, for example. Also for example, the BC cell battery can be of the low voltage type (typically 450 V for illustration). But it could be of the medium voltage or high voltage type.

[0047] It will be noted that in the example illustrated non-limitingly in [Fig.l] each (cellular) module MC comprises four cells CEn (n = 1 to 4) coupled between neighbors. But the number of cells CEn of a cellular module 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 [Fig.l] the cellular battery BC comprises six cellular modules MC. But the number of cellular modules MC can take any value greater than or equal to one.

[0049] Furthermore, the cellular battery BC is (here) housed in a battery case (or envelope) BB, preferably sealed, which also houses, in particular, the interface device DI, analysis devices (not shown), and the battery calculator CB. For example, the cellular battery BC, the battery case BB, the interface device DI, the analysis devices and the battery calculator CB can constitute a battery assembly (or "pack") EB.

[0050] The analysis devices are capable of determining current values ​​of quantities representative of the cells CEn (and in particular their respective cell voltages ucn), and communicate with the battery calculator CB so that the latter (CB) can receive these determined current values ​​and control the operation of the BC cell battery based on these determined and received current values.

[0051] It will also be noted that in the example illustrated non-limitingly in [Fig. 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).

[0052] As mentioned above, the invention notably proposes a monitoring method intended to enable monitoring of the operation of the cellular battery BC to detect an internal short circuit in a module MC.

[0053] This (monitoring) method can be implemented at least partially by the monitoring device DS (illustrated at least partially in FIGS. 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD. This monitoring device DS can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller.

[0054] The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the monitoring method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out at least one electrical or electronic operation.

[0055] In the example illustrated non-limitingly in Figures 1 and 2, the monitoring device DS is part of the battery computer CB. But this is not obligatory. Indeed, the monitoring device DS could comprise its own dedicated computer, which is then coupled to the battery computer CB, or could be part of another computer embedded in the system S and providing at least one other function.

[0056] As illustrated non-limitingly in [Fig. 3], the (monitoring) method, according to the invention, comprises a step 10-40 which is implemented each time the system S (here a vehicle) is in operation but no electric current flows in the cellular battery BC (for example, here, because the interface device DI is in its open state).

[0057] Step 10-40 of the method comprises a sub-step 20 in which, one (for example the monitoring device DS) determines for each cell CEn an information ivtjn which is representative of a temporal variation of its successive voltage measurements ucn.

[0058] Step 10-40 of the method also comprises a sub-step 40 in which, when information iv^n determined for two neighboring cells CEn (for example CEn-1 and CEn or CEn and CEn+1) represents temporal variations which behave in substantially opposite ways, an alarm is generated (for example the monitoring device DS triggers the generation) which is suitable for signaling a short circuit in the cell battery BC.

[0059] Here, the expression "temporal variations which behave in substantially opposite ways" means temporal variations which have respective values ​​of opposite signs and amplitudes whose absolute values ​​are identical or slightly different, substantially simultaneously. In other words, and as schematically illustrated in the diagram of the temporal evolution of the cellular voltages ucn of [Fig. 4], when the temporal variation of the cellular voltage ucn of a first cell CEn of an MC module is positive (growth), the temporal variation of the cellular voltage ucn' of a second cell CEn' (with n' = n-1 or n+1) of this same MC module (coupled to this first cell CEn) is negative (decrease). For example, the absolute values ​​of the amplitudes of the temporal variations of the neighboring CEn cells concerned may be identical to + / - 30%.Furthermore, the expression "substantially simultaneously" means exactly at the same time or almost at the same time within + / - 5 s.

[0060] It will be understood that these temporal variations behave in substantially opposite ways at the level of two neighboring CEn cells (for example CEn-1 and CEn or CEn and CEn+1) of the same MC module, it is considered that they are characteristic of an internal short circuit in the latter (MC). Indeed, in the absence of a short circuit between neighboring CEn cells, each CEn cell is electrically isolated from the other CEn' cells (with n' n), and therefore no short-circuit current can flow between these CEn and CEn' cells. On the other hand, in the presence of a short circuit between two neighboring CEn cells, a current can be created at each point of common potential (for example due to the conductive nature of the conductive liquid present in the BB battery case).Therefore, in the absence of electrical consumers connected to the cellular battery BC, the appearance of a short-circuit current will cause characteristic temporal variations, because they are substantially opposite, of the voltages ucn and ucn' of the neighboring cells CEn and CEn'. This is what is illustrated in [Fig.4].

[0061] More precisely, in the diagram of [Fig.4] are illustrated two examples of temporal variations (t (in seconds)), behaving in substantially opposite ways, of the cellular voltages uc2 (n = 2) and uc3 (n = 3) of second CE2 and third CE3 neighboring cells of the same MC module.

[0062] Consequently, by comparing the temporal variations of the cell voltages ucn and ucn' of the neighboring cells CEn and CEn' of each module MC, it is now possible to determine whether two of them behave in substantially opposite ways, and if so, reliably deduce that their module MC is subject to an internal short circuit. An alarm, signaling a short circuit in the cell battery BC, is then generated.

[0063] It will be noted that since the MC module in which the short circuit was detected is known, the alarm may possibly signal the identifier of this MC module.

[0064] The invention therefore makes it possible to significantly and reliably improve the safety of users of the system S, even though no sensor dedicated to detecting internal short circuits has been used.

[0065] It will also be noted that the alarm may be intended for a computer of the system S, such as for example the supervision computer CS, and / or for a user of the system S (for example the driver in the case of a vehicle), as well as possibly for an emergency service.

[0066] When the alarm is intended at least for the driver, its purpose may be to ask him to quickly leave the vehicle S (with any passengers). In this case, the alarm may be done by lighting a warning light on the vehicle S and / or by displaying a text message and / or by broadcasting an audible message. The warning light may be part of the dashboard of the vehicle S or be displayed on a display screen of the vehicle S (possibly that of the central instrument panel installed on or in the dashboard). It may be a dedicated warning light or a service warning light (not dedicated). The text message may be displayed on at least one screen of the vehicle S (for example the dashboard or the central instrument panel) or on the screen of a smartphone of the driver. The audible message may be broadcast by at least one loudspeaker of the vehicle S or of the aforementioned smartphone.

[0067] When the alarm is also intended for an emergency service, it can be transmitted by radio to the latter by a communication module of the vehicle S or by the aforementioned smartphone. This option is particularly advantageous because it can allow a relatively rapid intervention where the vehicle S has been immobilized by its driver (in order to evacuate it), such as to avoid thermal runaway of the cellular battery BC and thus prevent a fire from occurring in the vehicle S. This therefore also makes it possible to improve the safety of the vehicle S.

[0068] It will also be noted that each information ivtjn can be a value equal to a temporal variation or can simply be an identifier or a parameter which is representative of this temporal variation.

[0069] For example, in sub-step 20 of step 10-40 one (for example the device of DS monitoring) can determine for each cell CEn information ivtjn which is representative of a temporal variation of its successive voltage measurements ucn over a time interval it which is chosen and sliding. This makes it possible to avoid taking into account temporal variations occurring suddenly and in a non-sustainable manner, for example due to a very temporary malfunction of voltage sensors or a communication network (possibly multiplexed) of the system S, and therefore a priori not significant in a certain way of the presence of a real and lasting short circuit.

[0070] Also for example, in step 10-40 the time interval it may have a duration between 35 min and 45 min. As an illustrative example, this duration may be equal to 40 min. But other values ​​of this duration may be used. For example, the value of this duration may be chosen during the development phase of the system S (or of the cellular battery BC).

[0071] Also for example, and as illustrated non-limitingly in [Fig. 3], step 10-40 may also comprise a sub-step 10 in which one (for example the monitoring device DS) can determine for each cell CEn an average voltage ucmn from its successive voltage measurements ucn. In this case, in sub-step 40 one can generate (for example the monitoring device DS can trigger the generation of) the alarm when the information ivtjn determined for two neighboring cells CEn represents temporal variations with respect to their respective determined average voltages ucmn which behave in substantially opposite ways. This makes it possible to detect more easily and more precisely a growth or decrease trend in progress at the level of a cell CEn.

[0072] It will be noted that in sub-step 10 of step 10-40 one (for example the monitoring device DS) can determine for each cell CEn the average voltage ucmn from its successive voltage measurements ucn in the chosen time interval it. Thus, one has the same time scale for the average voltages ucmn and the information iv^n.

[0073] Also for example, in sub-step 20 of step 10-40 one (for example the monitoring device DS) can determine for each cell CEn a difference eun(t) between its last voltage measurement ucn(tl) and the average voltage ucmn(t), i.e. eun(t) = ucn(tl) - ucmn(t), t representing the instant considered. Then, in sub-step 20 one (for example the monitoring device DS) can determine for each cell CEn a cumulative difference cen(t) equal to the sum of the previous cumulative difference cen(tl) and the determined difference eun(t) (i.e. cen(t) = cen(tl) + eun(t)). Then, in sub-step 20, when a cumulative deviation cen(t) determined for the instant t is lower than a negative threshold sn (i.e. cen(t) < sn), one (for example the monitoring device DS) can associate with the cell CEn concerned a so-called negative information ivtin (j = 1). On the other hand, in the sub-step 20, when a cumulative deviation cen(t) determined for the instant t is greater than a positive threshold sp (i.e. cen(t) > sp), one (for example the monitoring device DS) can associate with the cell CEn concerned a so-called positive information ivt2n (j = 2).

[0074] Then, as illustrated non-limitingly in [Fig.3], step 10-40 can also comprise a sub-step 30 in which one (for example the monitoring device DS) can compare two by two the information ivtjn of neighboring cells within each module MC.

[0075] If there are not at least two neighboring CEn cells associated respectively with negative information ivtin and positive information ivt2n, we return to perform sub-step 10. On the other hand, when at least two neighboring CEn cells are associated respectively with negative information ivtin and positive information ivt2n, we generate (for example the monitoring device DS triggers the generation of) the alarm in sub-step 40.

[0076] It will also be noted, as illustrated non-limitingly in [Fig. 2], that the battery calculator CB (or the calculator of the monitoring device DS) may also comprise a mass memory MM1, in particular for storing each measured cell voltage ucn, as well as any intermediate data involved in all its calculations and processing. Furthermore, this battery calculator CB (or the calculator of the monitoring device DS) may also comprise an input interface IE for receiving at least the measured cell voltages ucn, possibly after having shaped and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2. In addition, this battery calculator CB (or the calculator of the monitoring device DS) may also comprise an output interface IS, in particular for generating and delivering each alarm message.

[0077] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the monitoring method described above to monitor in the system S the operation of the cellular battery BC in order to detect an internal short circuit by comparison of temporal variations of cellular voltages ucn.

Claims

Claims

1. Method for monitoring a cellular battery (BC) suitable for equipping a system (S) and comprising at least one module (MC) comprising at least two electrical energy storage cells (CEn), coupled between neighbors and each subject to successive voltage measurements at their terminals, characterized in that it comprises a step (10-40) in which, when no current flows in said cellular battery (BC), information representative of a temporal variation of its voltage measurements is determined for each cell (CEn), and, when information determined for two neighboring cells (CEn) represents temporal variations behaving in substantially opposite ways, an alarm is generated suitable for signaling a short circuit in said cellular battery (BC).

2. Method according to claim 1, characterized in that in said step (10-40) information representative of a temporal variation of its voltage measurements over a chosen and sliding time interval is determined for each cell (CEn).

3. Method according to claim 1 or 2, characterized in that in said step (10-40) an average voltage is determined for each cell (CEn) from its successive voltage measurements, and said alarm is generated when said information determined for two neighboring cells (CEn) represents temporal variations with respect to their respective determined average voltages behaving in substantially opposite ways.

4. Method according to the combination of claims 2 and 3, characterized in that in said step (10-40) said average voltage is determined for each cell (CEn) from its successive voltage measurements in said chosen time interval.

5. Method according to claim 3 or 4, characterized in that in said step (10-40) a difference between a last voltage measurement and said average voltage is determined for each cell (CEn), then a cumulative difference equal to a sum of a previous cumulative difference and said determined difference, then, when a determined cumulative difference is less than a negative threshold, so-called negative information is associated with the cell (CEn) concerned, while when a determined cumulative difference is greater than a positive threshold, so-called positive information is associated with the cell (CEn) concerned, and, when two neighboring cells (CEn) are associated respectively with negative information and positive information, the said alarm is generated.

6. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the monitoring method according to one of claims 1 to 5, in a system (S) comprising a cellular battery (BC) comprising at least one module (MC) comprising at least two electrical energy storage cells (CEn), coupled between neighbors and each subject to successive voltage measurements at their terminals, to monitor said cellular battery (BC).

7. Monitoring device (DS) for a system (S) comprising a cellular battery (BC) comprising at least one module (MC) comprising at least two electrical energy storage cells (CEn), coupled between neighbors and each subject to successive voltage measurements at their terminals, characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, when no current flows in said cellular battery (BC), in determining for each cell (CEn) information representative of a temporal variation of its voltage measurements, and, when information determined for two neighboring cells (CEn) represents temporal variations behaving in substantially opposite ways, in triggering generation of an alarm capable of signaling a short circuit in said cellular battery (BC).

8. System (S) comprising a cellular battery (BC) comprising at least one module (MC) comprising at least two electrical energy storage cells (CEn), coupled between neighbors and each subject to successive voltage measurements at their terminals, characterized in that it further comprises a control device (DC) according to claim 7.

9. System according to claim 8, characterized in that it constitutes a vehicle.

10. System according to claim 9, characterized in that it comprises at least one electric motor (MME) capable of being supplied with electrical energy by said cellular battery (BC).

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