AUTOMOBILE WITH BATTERY AND FUEL CELL, INCLUDING A MEANS FOR HEATING THE CELL DURING START-UP UNDER LOW BATTERY LOAD, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising: - an electric motor; - a fuel cell and a traction battery; - means for evaluating the power (PFC) and temperature (TFC) of the fuel cell; and the power (PB) of the battery; - a means for heating the fuel cell; and - a means for starting the electric motor on the fuel cell or the electric battery, characterized in that if the power and temperature (PFC, TFC) are below the power thresholds (S2, S3), then the starting means activates the starting of the electric motor on the fuel cell and the heating of the fuel cell. The invention also relates to a method and a program based on such a vehicle. Figure 2

Description

Title of the invention: AUTOMOBILE WITH BATTERY AND FUEL CELL, INCLUDING A MEANS FOR HEATING THE CELL DURING START-UP UNDER LOW BATTERY LOAD, METHOD AND PROGRAM BASED ON SUCH A VEHICLE

[0001] The invention relates to the field of motor vehicles comprising a traction system connected to a traction battery and a fuel cell. The invention relates more particularly to the management of electrical energy between the traction battery and the fuel cell.

[0002] In the case of such vehicles, vehicle starting problems and breakdowns may occur when the fuel cell is cold and the battery has a low state of charge.

[0003] Document CN116198390 describes a method and system for energy management for the starting and operation of a fuel cell automobile. Energy management varies according to six scenarios based on ambient temperature and state of load. This document does not propose a solution to the aforementioned problem.

[0004] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose a solution to ensure the starting of the vehicle and avoid a breakdown when the fuel cell is cold and the battery has a low state of charge.

[0005] To achieve this objective, the invention proposes a motor vehicle comprising: - an electric motor; - an electric motor power supply system, which includes a fuel cell and a traction battery; - a means of evaluating the power of the battery; - a means of evaluating the temperature of the battery; - a means of evaluating battery power; - a means of heating the fuel cell; and - a starting means for initiating the starting of the electric motor based on a power supply from the fuel cell or the electric battery, characterized in that if the fuel cell power is below a first power threshold, the battery power is below a second power threshold, and the fuel cell temperature is below a temperature threshold, then the means The start-up activates the heating means which heats the fuel cell, and the starting means actuates the starting of the electric motor based on the power supplied by the fuel cell.

[0006] Advantageously, the invention offers an energy management solution that allows the fuel cell to be preheated when the battery has a low state of charge in order to limit vehicle starting problems and breakdowns.

[0007] The invention improves the reliability of starting and vehicle operation under low-temperature and low-battery conditions by optimizing the use of available energy. This prevents the user from experiencing a breakdown. Furthermore, it protects key components of the motor vehicle, such as the fuel cell and the battery.

[0008] Preferably, the first power threshold is 0W; the second power threshold is between 3kW and 16kW, preferably 8kW; and the temperature threshold is between 3°C and 20°C, preferably 10°C.

[0009] This helps to preserve the usual batteries for cold starts.

[0010] Preferably, the heating means heats the fuel cell to a temperature between 5°C and 20°C, preferably 15°C.

[0011] This allows the optimal operating temperature of the fuel cell to be reached.

[0012] Preferably, the traction battery is connected to a DCDC converter which is connected to the electric motor, characterized in that the starting means limits the power of the DCDC converter so as to actuate the starting of the electric motor on the basis of the fuel cell supply.

[0013] This makes it easy to limit the power allocated to the electric motor and to start on the basis of the fuel cell.

[0014] Preferably, a means of evaluating the resulting available power of the cell compared to the battery; characterized in that the means for evaluating available power assesses a limitation of available power between the battery and the fuel cell based on the following formulas: pHVB-rcS _pHVB +pFCS with r AvlDchaxxx ~ ^AvlDchüxxx Mnst P^^jCS ' the available power limitation; 'XXX , the traction battery power; and r AvlDchaXxx 1 p^ts, the power of the fuel cell.

[0015] This allows for a precise evaluation of the resulting available residual power of the cell relative to the battery.

[0016] Preferably, the motor vehicle further includes electrical consumers connected to the fuel cell and the traction battery, characterized in that the evaluation means further evaluates a priority scale of electrical consumers as well as the power allocated to electrical consumers by means of the following formula: -rnax(ftmin(p““Hw PU ) )with p?1^;[ xj] ' the Power allocated to a given consumer; P^se, the power available in high-voltage networks; pPalse, the sum of the powers of electrical consumers having a higher priority than that of the consumer; pi, the power limit of the consumer; 1 Lim pi, the maximum power of the consumer. rMax r

[0017] This allows for an accurate assessment of the power allocated to consumers.

[0018] Another object of the invention relates to a method for controlling the starting of a motor vehicle according to the invention, characterized in that it comprises the following steps:

[0019] - a step to evaluate the power of the battery; - a step to evaluate the temperature of the battery; - a step to evaluate the battery power; - a start-up stage in which the electric motor is started based on a power supply from the fuel cell or the electric battery, characterized in that if the power of the fuel cell is less than a first power threshold, the power of the battery is less than a second power threshold, and the temperature of the fuel cell is less than a temperature threshold, then the fuel cell is heated, and the electric motor is started based on the power supply from the fuel cell. Preferably, the start-up control method further includes a step for evaluating the resulting available power of the fuel cell relative to the battery, in which a limitation of available power between the battery and the fuel cell is evaluated on the basis of the following formulas: = pF^ + pTcs with PAv^æS ' 'a limitation of available power; pHVB u, the power of the traction battery; and P^s, the power of the fuel cell.

[0020] Preferably, in the evaluation step, a priority scale for electrical consumers and the power allocated to electrical consumers are further evaluated using the following formula: = max(0;min(P^s <Lp^^ pU))avec pP^[idXj] ' the power allocated to a given consumer; P^6, the power allocated to the highest priority consumer; pCulsc, the sum of the powers of electrical consumers having a rSumEKo„H1Prio' 1 1 j higher priority than that of the consumer; p£. , the power limit of the consumer; pi , the maximum power of the consumer. rMax r

[0021] The invention further relates to a computer program comprising program code instructions for executing the steps of the startup control method according to the invention, when said program is running on a computer.

[0022] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures in which: - [Fig. 1] schematically illustrates an evolution of the charge states of the battery and the fuel cell as a function of time, with priority orders of consumers within the framework of the operation of a motor vehicle according to a preferred embodiment of the invention; and - [Fig.2] illustrates a diagram of the conditions for implementing a start-up based on the fuel cell within the framework of the invention.

[0023] The invention provides a system and method for managing high-voltage energy in a vehicle comprising a traction battery and a fuel cell. The management system of the invention allows the fuel cell (FCS) to be preheated when the high-voltage battery is at a low state of charge in order to ensure the vehicle starts and prevent the user from running out of power. This strategy also protects the fuel cell and the battery.

[0024] The control strategy is based on the following steps: - a step to detect the operating situation with the fuel cell in cold conditions and the high-voltage battery in low state of charge; - a step to calculate the resulting available power limitation between the battery and the fuel cell; - a step of calculating the power allocations of high-voltage electrical systems.

[0025] Regarding the detection of the operating situation, its evaluation is based on the logic diagram of [Fig.2].

[0026] The cold start request with the FC cell is deactivated (reference FC_0) in standard conditions. In a first scenario, if the instantaneous power of the fuel cell is greater than a first threshold, here 0W, then the cold start request with the FC cell remains deactivated (reference FC_0).

[0027] If the first hypothesis is negative, a second hypothesis is used to check whether the battery power in absolute value is less than the battery power at low state of charge (for example below a second power threshold S2 between 3kW and 20kW, preferably 15kW), and whether the fuel cell temperature is less than a first temperature threshold S3. If the second hypothesis is positive, the cold start request is activated (reference FC_1).

[0028] If the second hypothesis is negative, a third hypothesis is used to check whether the fuel cell temperature FC is above a second temperature threshold S4. If the third hypothesis is positive, the request to start with the cold cell is deactivated (reference FC_0). If the third hypothesis is negative, the process returns to the first hypothesis.

[0029] Regarding power and limiting calculations, the calculation of the available power of the battery to be used is determined as follows: If pFCS pfcs ° rhist > rThdAcvl then: P^pchaxxx - min ( Pd^^; PthnDcha ) with PLtaDcha = LUT ( SOCHVB; ) Otherwise _ p^^ > pFCS > pÇC^ or the startup query with the stack at Cold is activated, then: nHVB . nHVB pHVB “AvlDchaXxx — \ ^Dchaxxx” ^ThdLimDcha / ^LimDcha ^ThdLimDcha Otherwise pFCS pFCS . pFCS p PThdÀcv2 - PThdHys2 > Plnst 0 then: pHVB = pHVB .

[0030] If the fuel cell is operating, and this is detected by the hysteresis beyond the discharge power limit, the power for electric traction must be limited to the lower charge states of the high-voltage battery. This prevents the battery from discharging completely before the hydrogen tank is empty. If the fuel cell is off, the algorithm is the same as for conventional electric vehicles (BEVs).

[0031] The explanation is that if the vehicle is traveling at maximum speed, the energy supply from the fuel cell is insufficient, so the high-capacity battery The voltage must provide supplementary energy. Without this strategy, the high-voltage battery will completely discharge and the vehicle will stop, even though the fuel cell can still supply power. This strategy ensures a minimum state of charge in the battery as long as the fuel cell is operating.

[0032] The resulting available power between the battery and the fuel cell is: nHVB-FCS _ tjHVB , DFCS r AvlDchaxxx ~ FAvlDchaxxx *Inst

[0033] Regarding power allocations in high-voltage electrical systems, the calculation of the stabilized nominal peak power vector depends on the following flows: - the power available in the high-voltage networks (P^6), equal to the maximum power that the battery can supply (peak, nominal, stabilized), in addition to the power of the electrical machine in generator mode: D _ pHVB-FCS , pMELs-Gen • *AvlDcha ^AvlDehasxx + *Inst ' - the power limiting vector: p . _ [p1. pN. 1, depending on The activation, deactivation and power limit information for high voltage (HV) consumers, consists of two main functions: power limitation of consumers and the limiting vector for all electrical consumers.

[0034] Regarding the power limitation of electrical consumers, it is calculated for each high-voltage electrical consumer: - the DCDC converter (noted DC): its power is based on the maximum potential that the DCDC converter can provide, this depends on several parameters such as temperature, the voltage of the DCDC converter in the high or low voltage network; - the thermal system: its power is based on a mapping dependent on the state of charge (SOC) and the temperature of the high-voltage battery in the nominal case or only on the temperature of the high-voltage battery in the event of failure of the thermal system (cooling of the high-voltage battery); - etc.

[0035] In the case where the cold start request is active, a second limiting vector will be added for all electrical consumers on the high voltage side in order to ensure that there is more power for the thermal system, and to ensure the heating of the fuel cell to allow its activation.

[0036] The power limiting vector for high-voltage electrical consumers is based on: - the limitation of power from high-voltage electrical consumers;

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[0047] - the authorization to activate high voltage electrical consumers based on a "48V electrical system request" and / or an "internal high voltage electrical system mission" in connected mode (or "Plugln" in English) or not. Priority vectors for high-voltage electrical consumers allow for the implementation of a priority scale. These are priority index vectors denoted idx = [idx1 idxN] - the creation of these vectors is based on several flows such as the "48V electrical system demand" and / or the "48V electrical consumer needs". In the event of a cold start request, the priority order will be changed, placing the thermal system in second priority in order to ensure the heating of the fuel cell to allow its activation. Furthermore, an instantaneous power vector for consumers at 48V is provided: p_[p!pN]; and a calibration is used to define the maximum power. electrical consumers at 48V T itt — P — [p! P^ 1 Preferably, the state of the high-voltage electrical system is determined: In the first step, we calculate the power allocated to the highest priority electrical consumer using the equation: ^.[idxi] =max(0;min(P^1se; P[im; P^ax)) Priority index vectors allow us to know the component with the highest priority order index (the first index idxp. Using this index, we can determine the power limit of this electrical consumer (P^^) and the maximum power of the high-voltage consumer (P^). In the next step, we calculate the allocated power according to the following equation: ^maxfaminfp^p^^^ P^; PmJ) Priority index vectors allow us to know the component with the priority index] (the index idxj). Using this index, we can determine the power limit of this electrical consumer (pi. ) and the maximum power of the high-voltage consumer (p^ j • pPower CS( |a sum of the powers of the high-voltage electrical consumers voltage having a higher priority than that of the electrical consumer j. This power depends on the state of demand of the electrical system, power allocation vectors and instantaneous power vectors.

[0048] Using this index, we can determine the power limit of this electrical consumer (pJ) and the maximum power of the high-voltage circuit (pj). rMax

[0049] pPutse CS( |a sum of the powers of the high-power electrical consumers rSumElCo.!Hlffio 1 voltage having a higher priority than that of the high-voltage electrical consumer voltage j. This power depends on the state of demand of the high voltage electrical system, power allocation vectors and instantaneous power vectors.

[0050] The interest of the invention lies particularly in the limitation of maintenance operations: indeed, by avoiding breakdowns related to an impossible cold start with a battery in a low state of charge, this invention makes it possible to limit the repair and replacement operations of components under warranty.

[0051] The invention further implies an increase in the service life of key components: indeed, by protecting the fuel cell and the battery from damage related to improper use in cold conditions, the invention extends their service life, reducing premature replacement operations.

Claims

Demands

1. A motor vehicle comprising: - an electric motor (EM); - an electric motor power supply system, which includes a fuel cell (FC) and a traction battery; - a means for evaluating the power of the fuel cell (PFC); - a means for evaluating the temperature of the fuel cell (TFC); - a means for evaluating the power of the battery (PB); - a means for heating (TS) the fuel cell;and - a starting means actuating the starting of the electric motor (ME) on the basis of a power supply from the fuel cell (FC) or the electric battery, characterized in that if the power of the fuel cell (PFC) is less than a first power threshold, the power of the battery is less than a second power threshold (S2), and the temperature of the fuel cell (Tfc) is less than a temperature threshold (S3), then the starting means activates the heating means (TS) which heats the fuel cell (FC), and the starting means actuates the starting of the electric motor (ME) on the basis of the power supply from the fuel cell (FC).;

2. Motor vehicle according to claim 1, characterized in that the heating means (TS) heats the fuel cell (FC) to a temperature between 5°C and 20°C, preferably 15°C.

3. Motor vehicle according to any one of claims 1 to 2, wherein the traction battery is connected to a DCDC (DC) converter which is connected to the electric motor (ME), characterized in that the starting means limits the power of the DCDC (DC) converter so as to actuate the starting of the electric motor (ME) on the basis of the fuel cell (FC) supply.

4. A motor vehicle according to any one of claims 1 to 3, further comprising a means for evaluating the resulting available power of the fuel cell relative to the battery; characterized in that the means for evaluating the available power assesses a limitation of available power between the battery and the fuel cell based on the following formulas: rjHVB-FCS nHVB , nFCSavPC *AvlDchaxxx = r AvlDchaxxx + *Inst PAvlDdia^ ' 'a of available power; pVYR i , the power of the traction battery; and pFCS , the power of the fuel cell.

5. A motor vehicle according to claim 4, further comprising electrical consumers connected to the fuel cell (FC) and the traction battery, characterized in that the evaluation means further evaluates a priority scale (PI, P2) of the electrical consumers as well as the power allocated to the electrical consumers by means of the following formula: [PI, P2] | ' 'the power allocated to a given consumer; P1, the power available in the high-voltage networks; pPulse, the sum of the powers of the electrical consumers having a higher priority than that of the consumer; pi, the power limit of the consumer; pi, the maximum power of the consumer. rMax r

6. A method for controlling the starting of a motor vehicle according to any one of claims 1 to 5, characterized in that it comprises the following steps: - a step for evaluating the power of the fuel cell (PFC); - a step for evaluating the temperature of the fuel cell (TFC); - a step for evaluating the power of the battery (PB); - a starting step in which the electric motor (ME) is started based on a power supply from the fuel cell (FC) or the electric battery, characterized in that if the power of the fuel cell (PFC) is less than a first power threshold, the power of the battery is less than a second power threshold (S2), and the temperature of the fuel cell is less than a temperature threshold (S3), then the fuel cell (FC) is heated, and the electric motor (ME) is started based on the power supply from the fuel cell (FC).

7. A starting control method according to claim 6, further comprising a step of evaluating the resulting available power of the fuel cell relative to the battery, in which We evaluate a limitation of available power between the battery and the fuel cell on the basis of the following formulas: pHVB-FCS _ pHVB , pFCS with rAvlDchaxxx - rAvlDchaxxx + Hnst , the limitation of available power; PAvlDcha ' 'a Pu'ssancc of the traction battery; and P^s, the power of the fuel cell.

8. A start-up control method according to claim 7, characterized in that, in the evaluation step, a priority scale (PI, P2) of electrical consumers and the power allocated to the electrical consumers are further evaluated using the following formula: [P^aidXj] = max(ftmin(p^-PE^ PU, pU) )«« PaHq6 [^Xi] ' 'a Power allocated to a given consumer; p^se, the power allocated to the highest priority consumer; pl11186, the sum of the powers of the electrical consumers having a higher priority than that of the consumer; pj, the power limit of the consumer; pi, the maximum power of the consumer. rMax r

9. Computer program comprising program code instructions for performing the steps of the startup control method according to any one of claims 6 to 8, when said program is running on a computer.

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