FR3015124A1 - CHARGING A BATTERY - Google Patents

Abstract

A method of charging a battery from a charging device (1), characterized in that it comprises the following steps: - (E12) Estimation of the future temperature of the battery over a future period between a moment of beginning and end of period; - (E25) Planning of the battery charge in the future period according to the estimated future temperature of the battery in said future period, in order to minimize the calendar aging of the battery; - (E3) Charging the battery during at least one charge period defined during the planning stage.

Description

The invention relates to a method for charging a battery used at a charging device powered by at least one energy source. It also relates to a battery charging device as such implementing such a method. Finally, it also relates to a data medium comprising software means for implementing such a method.

There are many devices operating with a rechargeable battery, such as electric or hybrid motor vehicles. When the user of such an electrical device realizes that the charge of his battery is too low, he connects it to a recharging device which uses as input the power supplied by a source of electrical energy to transmit an output. charging current of the battery. This management of the charge of a battery can also be done automatically and autonomously, without the intervention of a user, the electrical device alone detecting a need for charging of its battery and being linked to a charging means of its battery.

When the electrical device concerned is an electric vehicle, the charging device of the battery may be in the form of a shelter defining a parking space and electrically equipped for the electrical connection with the battery. Such a shelter can be equipped with photovoltaic panels generating electrical energy which is used for recharging the vehicle's battery. In practice, the driver positions his vehicle under the shelter, electrically connects to a power socket arranged at the shelter, which usually has the effect of immediately initiating recharging of the battery of his vehicle. The charging phase is then automatically stopped by the charging system as soon as the battery reaches its full charge. Such existing battery charging methods are not optimized.

Indeed, the charging of the different batteries is generally initiated from their electrical connection with the system, with the objective of their full load, as has been explained above. It is even sometimes expected accelerated loads compared to nominal charging regimes provided by the manufacturer of the batteries, to allow a possible early reuse of the battery, to reduce the waiting time of its user. Naturally, such an approach causes premature aging of the batteries. In addition, it does not seek any optimization of a charging phase.

On the contrary, other charging systems, such as those described in documents WO201151144 and WO2013014238 provide for future planning of the charge of a battery bank in order to optimize the cost of the energy expended for the load and taking into account the future need for a certain battery.

However, all prior art approaches mentioned above do not take into account the phenomenon known as calendar aging, whereby a charged battery will undergo aging during a period of non-use. This aging is manifested by an alteration of the storage properties of the battery, leading to a decrease in its storage capacity and therefore its energy return. This calendar aging is all the more important as the charge stored by the battery is important.

This is why, to take into account this phenomenon, the document WO2012028572 proposes a particular solution which is based on a charge level of a battery generally lower than its maximum capacity, since this maximum capacity is rarely necessary and induces faster aging. of the battery by the phenomenon of calendar aging. However, the existing solutions for charging a battery are insufficient in that they do not reach an optimal compromise between two contradictory constraints: on the one hand, the need to provide a sufficient charge of a battery, sufficiently quickly , to meet a future need for battery use, and secondly the need to minimize the deterioration of the state of the battery by the calendar aging phenomenon, which tends to reduce the charge stored in the battery and to shift the charge of the battery over time to reduce the phases of non-use at high load. As can be seen from the previous presentations of the state of the art, existing solutions are generally best suited to one of these two contradictory constraints.

A general object of the invention is therefore to propose an optimized charging solution for a battery, which represents a better compromise than existing solutions.

More specifically, a first object of the invention to provide a charging solution of a battery to achieve a sufficient load and within a satisfactory battery time to meet the energy requirement for future use.

A second object of the invention is to provide a charge solution of a battery for minimizing aging of the battery by the calendar aging phenomenon.

A third object of the invention is to provide a charging solution of a battery compatible with a variety of uses, and optimizing the cost of the energy used for the load. For this purpose, the invention is based on a method of charging a battery from a charging device, characterized in that it comprises the following steps: - Estimation of the future temperature of the battery over a future period between a moment of beginning and end of period; - Planning of the battery charge in the future period according to the estimated future temperature of the battery in said future period, in order to minimize the calendar aging of the battery; - Charge the battery during at least one charge period defined during the planning stage.

The planning step can define at least one battery charge period and at least one idle period, the charging and idle periods being planned in the future period depending on the estimated future battery temperature.

The step of planning the charge of the battery can take into account at least one high threshold of temperature, in particular between 20 and 35 ° C inclusive, above which the aging of a battery is considered high, and can provide a period of charging the battery after a rest period during which the temperature is above the high temperature threshold. The step of planning the charging of the battery can provide an incomplete charge of the battery and / or a rapid charge of the battery substantially at the end of said future period, after a rest period of the battery, if the future temperature estimated exceeds a predefined high temperature threshold during this rest period.

The step of planning the charge of the battery can take into account at least a high threshold of state of charge, in particular between 40 and 60% inclusive, above which the calendar aging of a battery is considered high.

The step of planning the charge of the battery can predict the charge during two periods of charge separated by a rest period during which the estimated future temperature of the battery passes above a high temperature threshold Tsh a first partial load up to an intermediate state of charge at most equal to one of said at least one high state of charge threshold, during a first period preceding a rest period; then - a second load, especially until full load, for a second period following said rest period.

The step of scheduling the charging of the battery may comprise a step of comparing the state of charge of the battery on arrival at the charging device with a high threshold of state of charge, and may provide a step charging the battery to a state of charge corresponding to the high threshold state of charge if its state of charge is below the high threshold of state of charge, and / or may provide an initial period of discharge of the battery to a state of charge corresponding to the high threshold of state of charge if its state of charge is higher than the high threshold of state of charge. The step of planning the charge of the battery can take into account at least one low temperature threshold and / or a low threshold of state of charge and / or can take into account a temperature threshold defined as a function of a state of charge threshold. The battery charge planning step can provide for the immediate charge of the battery if the estimated future temperature falls below a low temperature threshold. The step of estimating the future temperature of the battery may comprise: a reception of weather forecast data, and / or a consideration of any shading of the battery; and / or - taking into account the precise position of a battery, as under the hood of a motor vehicle; and / or - taking into account an actual temperature measurement of the battery or ambient near the battery at a given moment; and / or - taking into account the day, the date and the time considered, and / or - taking into account historical data of temperature values measured in the past, and a predictive model based on these data. historical; a repetition of the future estimate of the temperature of the battery, to readjust the estimated future temperature over time. The charging method of a battery may comprise a step of determining all or part of the following parameters related to the battery, by a transmission by the battery or by a communication with a charging device with which it is connected, or by an estimate of the charging device: - the charge profile of the battery; - The state of charge of the battery, especially at its arrival time at the charging device; - A planned departure date of the battery; - the temperature of the battery; - A future need for battery power. The method of charging a battery may comprise a step of calculating a prediction of renewable energy production by a photovoltaic or wind renewable energy source, and the planning step may provide an incomplete charge of the battery up to at a maximum state of charge strictly less than 100% over a prediction period of high renewable energy production.

The invention also relates to a computing support readable by a computer, characterized in that it comprises a registered computer program comprising computer program code means for implementing the method of charging a battery as described above.

The invention also relates to a device for charging a battery, comprising at least one charging terminal electrically powered from at least one power generation source, the charging terminal being connectable to a battery to be loaded in a future period, characterized in that it comprises: - a device for indicating a date of beginning and end of said future period; a device for estimating the future temperature of the battery in said future period; a device for planning the charge of the battery over the future period as a function of the estimated future temperature of the battery over said future period, in order to minimize the calendar aging of the battery; and - a device for connecting the battery to the charging terminal to control the charging of the battery during at least one charging period defined in the planning step. The charging terminal can be arranged in a parking space for recharging a battery of an electric motor vehicle. These objects, features and advantages of the present invention will be set forth in detail in the following description of a particular embodiment made in a non-limitative manner with reference to the appended figures in which: FIG. 1 schematically represents a charging device a battery according to one embodiment of the invention. FIG. 2 diagrammatically represents an algorithm of a charging method of a battery according to one embodiment of the invention. Figures 3a to 3f illustrate different scenarios considered by the charging method of a battery according to the embodiment of the invention. Figures 4a and 4b illustrate various advantageous effects obtained by the method of charging a battery according to the embodiment of the invention.

FIG. 5 shows in more detail an algorithm according to a variant of the charging method of a battery according to one embodiment of the invention. Throughout this document, by "state of charge", or also by the name SOC, the term "state of charge" commonly used, means a battery charge level expressed as a percentage of the maximum capacity. charging the battery. On the other hand, this maximum charging capacity of a battery, that is to say the maximum amount of charge it can store, decreases with time, this phenomenon being referred to as the aging of the battery . An index called "state of health" or also SOH, because of the English name "state of health" commonly used, to measure the aging of the battery at a given time. This index is defined as the reference capacity of a battery at the instant considered divided by this reference capacity in new condition. The invention is particularly interested in the minimization of calendar aging, defined above, which represents one of the aging phenomena of a battery.

In addition, in this document, said calendar aging corresponds to the aging of the battery at rest, that is to say outside periods of charging or discharging the battery. The so-called cycling aging occurs in periods of activity when the battery is charging or discharging. In any case, the aging of the battery is accelerated when the temperatures are high and this aging is even more pronounced that the state of charge is high. It is furthermore considered that the battery is in cycling period, in charge or discharge, when the current passing therethrough is significant, that is to say at least equal to 0.1% of the nominal current that can be discharged. by the battery. Thus, in the case where the battery mainly supplies an electrical power device, such as a car engine, and also supplies an auxiliary electrical device (electronic card), the consumption of the auxiliary device is often much less important than that of the device. electric power (a ratio of 10, 100 or more, between the powers, and generally of the order of one hundred microamperes, at most a few milliamps) and it will be considered later that the battery is at rest if only the auxiliary device is powered. In other words, the concept of rest or activity is defined according to the electrical device of higher power can be powered by the battery. The invention will be illustrated in the case of an electric motor vehicle as an example. Such an electric vehicle can be an electric bike, an electric car, a segway personal transporter, an electric scooter, etc. Naturally, the invention could easily be transposed to any electrical device equipped with a battery for its power supply, and requiring recharging phases of its battery. In addition, for reasons of simplification, it will be considered in the following description that each vehicle is equipped with a single battery. However, the process could of course be applied similarly to vehicles with multiple batteries. Therefore, the invention applies to the problem of the charge of a battery, especially in the case where we know the date for which the load must be performed. Nevertheless, it will be seen that the method of the present invention can be implemented even in the absence of such a date. FIG. 1 thus schematically represents a system implementing the method of charging a battery according to one embodiment of the invention, in which a battery charging device 1, connected to one or more sources of power generation. electrical S (j) by an electrical connection 2, is able to charge the battery 11 of an electric vehicle 10 via a terminal 8 for an electrical connection with the battery of the motor vehicle. In the illustrated example, the charging system comprises various types of energy sources: renewable and intermittent energy sources, from photovoltaic panels 3 for local production of solar electric power and wind sources 5, which can be local or distant, and traditional energy sources 6 (gas, coal, nuclear ...), whose electrical energy is accessible via an electrical network 4. The charging device 1 comprises an intelligence, under the form of a logic processing unit, for example any type of computer 7, allowing the implementation of the battery charging method which will be detailed later, and in particular the implementation of an associated algorithm, to determine the charging conditions of a connected battery 11. The computer 7 comprises memories and software modules, computer programs. The charging device may comprise a data storage medium, readable by the computer, on which is recorded a computer program comprising software means for implementing the steps of the charging method which is the subject of the invention. on the other hand, the charging device 1 comprises a communication device 9 for exchanging data with the vehicle and / or its driver, such as the charge level of the battery 11, the desired charging requirement and / or the envisaged departure time. These data, which will be detailed in the following description of the charging process, can be transmitted to the charging device 1 by the driver himself, via a human-machine interface, or manually, from example of an electronic calendar, a telephone, an electronic message, or automatically, via the electric vehicle itself, etc. The communication device 9 also makes it possible to receive data from an external system, for example weather forecast data.

According to the embodiment of the invention, the charge of the battery takes into account the phenomenon of the calendar aging of the battery. As has been explained above, this aging depends on the charge stored in the battery. The invention further notes that this calendar aging also strongly depends on the temperature of the battery. Following these elements, the charging process of the battery will notably plan the load to be achieved in the future taking into account the estimated future temperature of the battery. To refine this approach, this consideration of the temperature will be combined with the state of charge of the battery, in an advantageous embodiment.

We will now describe, in connection with Figure 2, an embodiment of a method of charging a battery, implemented by the charging device 1 described above. This method makes it possible to plan the charge of the battery over time, and in particular to determine at what moment the charge must be engaged and possibly stopped, in what conditions this charge must be carried out, and up to what state charge (how much charge is stored in the battery). The charging method comprises a first phase El of initialization, 5 definition and storage of important parameters, then used in a second phase E2 for defining future charging conditions, before the implementation of this charge in a third phase E3 . In this embodiment, the first phase E1 first comprises a step E1 of determining parameters related to the battery to be charged. In particular, the following parameters may be considered, depending on the embodiment: the charge profile of the battery, as supplied by the battery manufacturer, for example; - The state of charge of the battery, which can be transmitted by the motor vehicle for example, or alternatively be estimated by the charging device by any means; - a planned departure date of the battery; The temperature of the battery; - As an option, a future need for battery energy, depending on the future route planned by the driver after the departure date. These parameters can be automatically transmitted by the on-board computer of the vehicle when it enters the charging system, by any means of remote communication with the computer 7 of the charging device 1 for example. This step thus allows the acquisition by the charging device 1 and the memorization of certain parameters useful for planning the charge of the battery, as will be detailed later. The first phase E1 of the method comprises a second estimation step E12 of the future evolution of the temperature of the battery over time, over a future period considered. This future period can either be predefined, from a fixed future time to be considered, or extend to an estimated or expected starting time of the motor vehicle (and therefore the battery). According to this embodiment, the charging device 1 receives by its communication device 9 weather forecast data, which allow it to deduce an estimate of the evolution of the temperature of the battery on the future period considered. For this, it implements a first calculation taking into account the peculiarity of the parking space associated with the charging device 1, where the battery is positioned during this stationary period, to take into account any shading, which may vary in the time, over the period considered. The shading can be known from the charging device 1 by past measurements, especially on sunny days. This first calculation thus uses a first law for estimating the temperature at the parking space from weather forecast data. Then, the estimated temperature takes into account the precise positioning of the battery, under the hood of a motor vehicle in the embodiment considered. For this, a second calculation, from a second law, obtained empirically or by any physical model, allows the deduction of the temperature under a hood of a motor vehicle from the temperature at the parking place. This last temperature can be likened to the estimated future temperature of the battery. Optionally, this estimation calculation can also take into account a measurement of real temperature at a given moment, for example to correct the parameters and / or laws of the calculations mentioned above. Naturally, this estimation step E12 can be implemented differently. Thus, according to a first variant, it may be based on a local periodic measurement of the temperature, then on an estimate of the future temperature of the battery according to the date and time considered, and / or taking into account data including temperature values measured in the past. In particular, this temperature at the parking place can be estimated from a self-learning based on temperature measurements made the few days prior to this estimation calculation.

According to another variant, the estimate of the future temperature of the battery can also take into account data transmitted by the motor vehicle, based on direct measurements by a temperature sensor disposed within the motor vehicle of past data and // or present of the temperature of the battery and / or an estimate of its temperature by an on-board computer of the motor vehicle. This estimation step E12 of the battery temperature can be implemented periodically, to readjust the estimated temperature over time. It can also be implemented on an ad hoc basis, in particular at the moment of arrival of a battery at the level of the charging device 1. Next, a second phase E2 of the method comprises a planning step E25, which has the objective of to plan the future charge of the battery over the future period considered, until the departure of the battery, in order to reach a sufficient load, defined by the process, while minimizing the calendar aging of the battery.

According to this embodiment, the method first takes into account a high temperature threshold Tsh, beyond which the calendar aging of the battery is considered problematic, and below which its calendar aging is considered acceptable. By way of example, this high temperature threshold may be set at 30 ° C., more generally between 20 ° and 35 ° inclusive, or even between 25 ° and 32 ° C. inclusive, in particular for a lithium battery, for example of the lithium-type type. ion. According to this embodiment, the method then takes into account a SOCsh high state of charge threshold, beyond which the calendar aging of the battery is considered problematic, and below which its calendar aging is considered acceptable. By way of example, this high threshold of state of charge can be set at 50%, more generally between 40% and 60% inclusive, or even between 45% and 55% inclusive, in particular for a lithium battery, for example lithium-ion type. The planning step E25 of this second phase E2 thus comprises a step of taking into account the estimated future temperature of the battery, in particular by comparing it with the high temperature threshold, to define the charge schedule of the battery. This planning will depend on the estimation of the future temperature of the battery.

The embodiment chosen is based on the example of an electric vehicle, and deals particularly with the most likely scenarios of a vehicle arriving at a parking lot at a certain time and leaving it on the same day a few hours later. The planning period thus extends over a few hours, at most a dozen hours. In this approach, four particular situations are envisaged, predefined, for which the battery charging strategies will be different. Naturally, the same principle can be adapted to any other period of planning period, and for any other number of battery charging situations and strategies. Various predefined scenarios are illustrated in FIGS. 3a to 3f, which represent a curve 15 of evolution of an estimated future battery temperature over a given period, a day in FIGS. 3a to 3d and 3f, as well as the times t i d arrival of a vehicle and departure tf. In the first predefined scenario, represented by FIG. 3a, the estimated future temperature of the battery remains high, above the high temperature threshold Tsh over the entire period considered, between an initial moment ti and a final instant tf. In such a case, it is inevitable to charge the battery in a period of high temperature, and therefore to potentially reach an adverse situation with strong calendar aging since the battery will be likely to accumulate a high load at a high temperature. . In this first scenario, the charging method according to this embodiment will at best limit this unfavorable situation by preferably implementing at least one of the following two actions: the charge will be carried out at a fast rate, it is that is faster than a nominal load. Such an action has the effect of enabling the charge to be initiated as late as possible, and therefore of reducing the storage time of a high charge at high temperature of the battery, and therefore its aging; and / or - The charge is carried out incompletely, that is to say up to a value lower than the maximum charge that the battery could receive, voluntarily stopping the charge before reaching the end of charge criteria defined by the battery manufacturer to achieve a full charge. By way of example, the maximum state of charge can for example be set at 80%, more generally between 70% and 90%, and even between 75% and 85%, to form a compromise between a load that is sufficient for future use. of the battery while limiting its aging due to a high temperature and a high SOC. Indeed, it turns out in practice that the aging at high temperature is often significantly accentuated when the state of charge exceeds this level. One can thus plan a rest period before time t1 (when the temperature is high), for example between t1 and t1, and a charging period between time t1 and time tf. The calendar aging is minimized on the first rest period (t1 to t1), and the aging is also minimized throughout the future period. The time t1 of start of charge is the latest possible. It should be noted that accelerated charging tends to age the batteries more quickly (compared to a normal charge). Nevertheless, for a majority of battery chemistries, rapid recharge-induced aging is less compared to high-temperature calendar aging and high SOC state of charge (greater than about 50% or worse, greater than about 80%).

According to a possible variant, in the case where the state of charge at the initial instant ti is relatively high, for example greater than about 50%, it will be possible to provide a discharge period for the battery, from the initial instant ti up to at a time t2 shown in Figure 3a, before a high temperature rest period between times t2 and t1, so as to lower the state of charge of the battery to a value less than 50% to minimize calendar aging during this period of rest at high temperature.

In the second scenario, represented by FIG. 3b, the estimated future temperature of the battery is low, remains below the high temperature threshold over the entire future period considered (between t 1 and t f). In such a case, the situation is the most favorable since the calendar aging is considered to be small. To limit it to the maximum, the battery will be charged at any rate, preferably at nominal speed, and at a time as late as possible. The charging start time t1 can thus be calculated to reach a complete charge, and therefore a charging state substantially equal to 100%, at the start time tf provided for the battery. The battery will thus be in a state of rest between instants t1 and t1, then charging between times t1 and tf. In the third scenario, represented by FIG. 3c, the estimated initial and final future temperatures of the battery are low (at times t 1 and t f). However, during an intermediate period, the temperature is high, above the high temperature threshold. In such a case, one will seek to minimize the level of state of charge during the period at high temperature. The charging method may for example consider the times tup and tdown for which the estimated future temperature respectively passes above and below the high threshold Tsh, and implement the load in two parts: - During a first period between a time t1 (after ti) and the time tup, the charge is made, as late as possible, to reach a maximum intermediate charge state which corresponds to a maximum acceptable state of charge to not significantly degrade the battery when a consecutive period of heating at high temperature. By way of example, the maximum intermediate state of charge in this first period can be set at 50%, more generally between 40% and 60%, and even between 45% and 65% (this value can be taken as equal to the value SOCsh defined above); - As soon as the temperature falls below the high threshold, from the moment tdown, a second charging period can be carried out to reach if possible the full charge on the departure date tf of the battery. This approach ensures that the state of charge does not exceed a maximum value during the period at high temperature, to limit the calendar aging of the battery. In a fourth scenario, represented by FIG. 3d, the estimated future temperature of the battery at the initial instant ti is small while the temperature at the final instant tf is high, above the high threshold of temperature. In such a case, it is necessary to seek, as in the first situation, to reduce at best the accumulation of a high state of charge during a high battery temperature. For this, the same charging strategy as in the first scenario can be implemented, with a moment of charging start at time t1 in the high temperature period as late as possible. Note however that the situation is more favorable insofar as it is possible to consider charging a little battery at the beginning of the future period while the temperature is below the high threshold Tsh, as represented between times t2 and t3 , while maintaining a state of charge lower for example equal to 50% (this value may correspond to the value of SOCsh defined above) before a consecutive rest period between instants t3 and t1, comprising at least a portion at high temperature. Indeed, since the charge of the battery tends to heat the battery, it is better to charge the battery when the temperature is not too high to not accelerate aging. Naturally, the charging method according to the invention is not limited to the four scenarios predefined by the embodiment described above. Other scenarios could be envisaged, for example with more complex temperature profiles, which could be applicable in particular if a longer period of planning is considered, of several days or even weeks.

Thus, FIG. 3e illustrates by way of example a scenario in which the temperature profile has several oscillations above and below the high temperature threshold Tsh, which can for example occur over a considered period of almost two years. days between times ti and tf. In such a scenario, load planning can be similar to that chosen in the fourth previous scenario. Since the final instant tf occurs in a period at high temperature, the charge will be made as late as possible from a time tl close to the final instant tf. On the other hand, optionally, one or more partial charges can be implemented between instants t2 and t3 intermediate, during low temperature periods, under the high temperature threshold. FIG. 3f illustrates another scenario which considers a low temperature threshold Tsb, in addition to the high threshold Tsh. It will be detailed later. The method therefore comprises a step of observing the estimated future temperature of the battery over the future period considered to select the predefined scenario that corresponds to the estimated situation, or which is closest to it. Each typical scenario can be defined by the following data: a temperature profile, and / or certain particular temperatures, especially for certain times when this temperature reaches or falls below a threshold; - One or more load criteria, to define the planning of the load. Then, when the load planning has been defined, the method triggers the charging of the battery as such, as planned, in a third phase E3. As a remark, according to an alternative embodiment of the method, iterations of the previous steps can be imagined, to adjust the planning during the period considered, in particular to take into account a possible change in the actual temperature of the battery that s would distance the estimated future temperature. These iterations can be periodic, or triggered by a particular predefined event, such as a difference between the actual temperature of the battery and its estimated temperature that exceeds a threshold.30 Naturally, the actions chosen to define the charging strategy have been explained as example. It is possible to imagine other solutions to reach other compromises, especially depending on whether we want to limit more or less calendar aging.

In any case, the future charge of the battery is planned according to the estimated future temperature of the battery, in particular with a view to minimizing the accumulation of a high charge with a high temperature.

According to a variant of the method described above, the initial state of charge of the battery is taken into account. For this, the method comprises a step of acquiring the initial state of charge of the battery, preferably during step E11. This approach makes it possible to take into account the fact that if this state of charge is low, under a high threshold of the SOCsh state of charge, then the phenomenon of calendar aging can be neglected. In this case, the battery can be charged, regardless of the temperature, until its state of charge reaches the threshold value. Then, the process can be continued by observing the temperature according to the principle explained above. This approach makes it possible to start the load earlier when it is very low, to ensure that the user will have a minimum state of charge in his battery, for example if he decides to recover his vehicle earlier than expected.

In this variant, the method thus implements a step E21 for comparing the state of charge SOC of the battery with a threshold of state of charge, then a step of charging E22 of the battery to reach this threshold if its state of charge is lower. This threshold may correspond to the high threshold of state of charge mentioned above, and be substantially 50%, or even between 40 and 60%. According to another variant embodiment, if the state of charge of the battery is above the threshold value when comparing step E21, then it may be decided to implement a step of discharging the battery up to this threshold value. This discharge decision can alternatively be implemented only after the step of observing the estimated future temperature of the battery, and only if the latter will exceed the high temperature threshold. Note, an implementation of the method of the invention with battery discharge can be advantageous in the case where multiple charging terminals are provided at a charging device, to manage the charging of several batteries simultaneously. In such a situation, the energy from the discharge of one battery can be exploited for charging another battery. The method has been illustrated previously on the basis of the choice of the battery charge strategy on the basis of a high temperature threshold Tsh, and possibly taking into account a SOCsh high state of charge threshold. Different alternative embodiments can be obtained by considering several temperature thresholds and / or several thresholds of state of charge, to allow to define a greater number of planning strategies.

For example, an alternative embodiment of the method is based on taking into account a low temperature threshold Tsb, advantageous to take into account the fact that it is not possible to recharge a battery below this threshold without causing degradation . In this embodiment, if it turns out that the estimated future temperature of the battery will fall below this low temperature threshold, the load is anticipated, for example triggered immediately, to be sure to be able to charge the battery, fully or to the state of charge corresponding to the high threshold of state of charge, before the temperature of the battery falls below this threshold. If the outside temperature is already below this threshold when the battery arrives, it is advantageous to engage the charge immediately, while the battery is still hot since the vehicle has just run. Thus, FIG. 3f illustrates a scenario taking into account a low temperature threshold Tsb, in addition to the high temperature threshold Tsh. The estimated future temperature of the battery has a profile which will first fall below the low threshold Tsb, then rise above the high threshold Tsh, before the final instant. In this configuration, the first action consists of a first charge period, up to a charge state corresponding to the high threshold SOCsh, between times t1 and t2: beyond time t2, the temperature is below the threshold low and the charge is no longer possible. Then, the load is completed between times t1 and tf. By this strategy, it is noted that the battery remains at rest between times t2 and t1, under favorable conditions, especially during the tup to tl period during which the temperature is high. In addition, it may be harmful to maintain a state of charge too low, not only because it would not allow a great responsiveness when needed earlier than expected battery, but also because in practice the battery can be during the rest phases by an auxiliary electronic device associated with the battery and, although very low currents are often necessary, the battery charge can go down significantly if the rest period is very long and its level can become critical and lead to damage to the battery, often resulting in aging of the battery. Thus, according to a complementary variant, a low state of charge threshold SOCsb is defined, and the planning ensures that the state of charge is at least brought above this low threshold during the future period.

As a remark, in the variants where two high and low thresholds are defined for respectively the temperature and the state of charge, the method will finally have the effect of maximizing the duration during which the battery will be in a state defined by the rectangle 16 illustrated. 4a, which thus represents the ideal conditions for a rest period (of non-use) of the battery, limiting as much as possible the duration in the gray part 17 which represents the states of the battery with strong calendar aging.

According to another variant embodiment, it is possible to link the value of the temperature with that of the state of charge, and to carry out the steps of observing these quantities in a combined manner and no longer by distinct and successive approaches. Indeed, the high temperature threshold can be chosen all the lower as the state of charge of the battery is high. This approach is illustrated by curve 18 of FIG. 4b, which represents the high temperature threshold as a function of the high threshold of the state of charge. All the points to the left of this curve represent favorable states, at low calendar aging of the battery, while the states to the right in the gray area 19 are to be avoided. Thus, the scheduling of the battery charge will minimize the time during which the idle battery (not used) will be in a state on the right of this curve 18. Figure 5 illustrates an algorithm that can be implemented by software of a calculator of a charging device, which implements a charging method according to one embodiment of the invention, taking a combination of the possible steps explained above. This algorithm takes the steps El 1, El 2, E21, E22 which have been presented previously. It then comprises the implementation of a planning step E25 incorporating the principles presented above if the state of charge of the battery is greater than a high threshold of state of charge. Otherwise, the calendar aging phenomenon is considered acceptable. As it explicitly appears on the algorithm, when the state of charge of the battery is higher than a high threshold of state of charge, four cases are considered, identified by simple tests based on the estimated future temperature of the battery. According to the results of these tests, the load planning is defined, so as to reach the load necessary for x% at the moment of departure of the vehicle.

The invention thus makes it possible to reduce the periods with higher calendar aging, as has been described on the basis of a strategy defined from the estimated future temperature of the battery. According to the embodiment described, this strategy is defined from simple tests that have been set out as examples. As a variant, any other algorithm, any calculation, making it possible to define a strategy as a function of the estimated future temperature of the battery, thus to fix at least one load parameter, such as a charging instant, a charge setpoint level, a charging regime, depending on the estimated future temperature of the battery can achieve an equivalent effect. Thus, the invention generally relates to the definition of a future charge of a battery according to its estimated future temperature.

According to another variant, the date of departure of the battery is unknown, for example because the driver did not indicate it to the charging device. In such a situation, a duration for example equal to 24 hours can be taken by default as a future period. A default value will preferably be chosen which corresponds to the average duration of parking on the terminal considered. Note, in all these process variants, a step of measuring and / or evaluating the state of charge of the battery is implemented, in particular during its charging. All variants of the battery charging method described above can be combined to form other embodiments.

The method of the invention can be implemented with any type of battery, for example lithium type as mentioned above but also NiMH. In addition, although the method has been described in the context of electric vehicles, it can of course be implemented for charging any battery of any device. In addition, the invention may be combined with other approaches for managing a battery, and a user may have the choice between several modes of operation, including a mode for example called "battery preservation mode", wherein the charge of the battery would be managed according to the method of the invention. A user could make this choice through an interface at the dashboard of a motor vehicle or through a human machine interface of the charging device. On the other hand, this same man-machine interface could transmit an alert signal when the battery is in a state of strong calendar aging, to allow a user to possibly choose in response a suitable strategy. In addition, for all the loads planned by the charging device, it can also remain a flexibility on the moment of start of charge, without or with little impact on the calendar aging of the battery. In such a situation, it may then be decided to choose the charging time according to a complementary criterion such as the minimum cost of the load or the maximum use of the energy produced by a renewable energy source. In particular, in the case of a charging device associated with a photovoltaic power generation, the charging method described above can be adapted to allow charging from the energy coming from this source while maintaining the objective of minimizing calendar aging, even though there is an additional paradox in the fact that this energy will then be most available generally at the hottest times. The charging method as described above can then more generally schedule a charge during periods of high irradiation, even if the temperature is high, but an incomplete charge, up to a set point at a charge state less than or equal to 80 %, even less than or equal to 65%, or even less than or equal to 50%. The additional load will then be planned if possible in a lower temperature period.25

Claims (15)

REVENDICATIONS1. A method of charging a battery from a charging device (1), characterized in that it comprises the following steps: - (E12) Estimation of the future temperature of the battery over a future period between a moment of beginning and end of period; - (E25) Planning of the battery charge in the future period according to the estimated future temperature of the battery in said future period, in order to minimize the calendar aging of the battery; - (E3) Charging the battery during at least one charge period defined during the planning stage. 2. Method of charging a battery according to the preceding claim, characterized in that the planning step (E25) defines at least one charging period of the battery and at least one rest period, the charging and charging periods. rest being planned during the future period depending on the estimated future temperature of the battery. 3. A method of charging a battery according to claim 2, characterized in that the planning step (E25) of the charge of the battery takes into account at least one high temperature threshold, in particular between 20 and 35 ° C inclusive, above which the calendar life of a battery is considered high, and provides a period of charging the battery after a rest period during which the temperature is above the high temperature threshold. 4. A method of charging a battery according to claim 3, characterized in that the planning step (E25) of the charge of the battery provides an incomplete charge of the battery and / or a rapid charge of labatterie substantially to the end of said future period, after a rest period of the battery, if the estimated future temperature exceeds a preset high temperature threshold during this period of rest. 5. Method for charging a battery according to one of the preceding claims, characterized in that the planning step (E25) of the battery charge takes into account at least one high threshold state of charge, in particular between 40 and 60% inclusive, above which the calendar aging of a battery is considered high. 6. A method of charging a battery according to the preceding claim, characterized in that the planning step (E25) of the charge of the battery provides charging during two periods of charge separated by a rest period during which the estimated future temperature of the battery passes above a high temperature threshold Tsh: - a first partial load up to an intermediate state of charge at most equal to one of said at least one high threshold of state of charge during a first period preceding a rest period; then - a second load, especially until full load, for a second period following said rest period. 7. A method of charging a battery according to the preceding claim, characterized in that the planning step (E25) of the battery charge comprises a step of comparing (E21) the state of charge of the battery to its arrival at the charging device (1) with a high threshold of state of charge, and provides a charging step (E22) of the battery to a state of charge corresponding to the high threshold of state of charge if its state of charge is below the high threshold of state of charge, and / or provides an initial period of discharge of the battery to a state of discharge corresponding to the high threshold of state of charge if its state of charge is greater than the high threshold of state of charge. 8. A method of charging a battery according to one of the preceding claims, characterized in that the planning step (E25) of the battery charge takes into account at least a low temperature threshold and / or a threshold low state of charge and / or in that it takes into account a temperature threshold defined as a function of a state of charge threshold. 9. A method of charging a battery according to the preceding claim, characterized in that the planning step (E25) of the charge of the battery provides for the immediate charge of the battery if the estimated future temperature falls below a low threshold of temperature. 10. A method of charging a battery according to one of the preceding claims, characterized in that the estimation step (E12) of the future temperature of the battery comprises: - reception of weather forecast data, and / or - taking into account any shading of the battery; and / or - taking into account the precise position of a battery, such as under the hood of a motor vehicle; and / or - taking into account an actual temperature measurement of the battery or ambient near the battery at a given moment; and / or - a consideration of the day, date and time considered, and / or - a consideration of historical data of temperature values measured in the past, and a predictive model based on these historical data ; a repetition of the future estimate of the temperature of the battery, to readjust the estimated future temperature over time. 11. A method of charging a battery according to one of the preceding claims, characterized in that it comprises a step (El 1) of determining all or part of the following parameters related to the battery, by a transmission by the battery or by communication with a charging device with which it is connected, or by an estimation of the charging device (1): - the charge profile of the battery; - The state of charge of the battery, especially at its arrival time at the charging device (1); - A planned departure date of the battery; - the temperature of the battery; - A future need for battery power. 12. A method of charging a battery according to one of the preceding claims, characterized in that it comprises a step of calculating a prediction of renewable energy production by a photovoltaic or wind renewable energy source, and in that the planning step (E25) provides an incomplete charge of the battery up to a maximum state of charge strictly less than 100% over a prediction period of high production of renewable energy. 13. Computer support readable by a computer, characterized in that it comprises a computer program recorded comprising computer program code means 25 for implementing the method of charging a battery according to one of the preceding claims. 14. A charging device for a battery, comprising at least one charge terminal (9) electrically powered from at least one power generation source (5, 30 6), the charging terminal being connectable to a battery to be charged in a future period, characterized in that it comprises: - a device for indicating a date of beginning and end of said future period; a device for estimating the future temperature of the battery in said future period; a device for planning the charge of the battery over the future period as a function of the estimated future temperature of the battery over said future period, in order to minimize the calendar aging of the battery; and - a device for connecting the battery to the charging terminal for controlling the charging of the battery during at least one charging period defined in the planning step. 15. Device for charging a battery according to the preceding claim, characterized in that the charging terminal (9) is arranged in a parking space for recharging a battery of an electric motor vehicle.