Method for determining surface regeneration parameter of contact surface of current contactor, method for determining aging factor of contact surface of current contactor taking into account surface regeneration parameter, and method for regenerating contact surface of current contactor

Abstract

The invention relates to a method for determining a surface regeneration parameter of a contact surface (26) of a current contactor (20), in particular in a vehicle, said surface regeneration parameter representing a regeneration of the contact surface (26) of the current contactor (20) during a closed state of the current contactor (20), wherein the method comprises the steps of determining a load current flowing through a closed current contactor (20), determining a duration during which the current contactor (20) is closed, and determining the surface regeneration parameter based on the determined load current and the determined duration.

Description

Technical Field

[0001] The invention relates to a method for determining a surface regeneration parameter of a contact surface of a contactor, in particular a contactor in a vehicle. The invention further relates to a method for determining an aging factor of a contact surface of a contactor, in particular a contactor in a vehicle, taking into account such a surface regeneration parameter. The invention further relates to a method for regenerating a contact surface of a contactor, in particular a contactor in a vehicle, based on such a surface regeneration parameter. Background Art

[0002] Modern vehicles have a large number of electrical connections which have or must have so-called contactors in order to protect the electrical components connected to these electrical connections. A contactor or simply a contactor is an electrically or electromagnetically operated or operable switch which is designed in particular for high electrical powers and has two predetermined switch positions, an open switch position in which the electrical connection is interrupted and a closed switch position in which the electrical connection is closed, wherein in the case of a closed connection the resulting electrical connection is electrically conductive or can conduct load current.

[0003] Contactors are used in particular for protecting electrical components connected to an electrical connection in which the contactor is located. Unlike other switches such as relays, contactors are not only designed for high power, but are also always double interrupted. In contrast, relays are designed for lower breaking capacity and are single interruption switches. Another very important feature of contactors is the presence of so-called radio interrupters, which are used to prevent arcs from occurring at the switching contacts of the contactor or to quickly disintegrate the arc in the event of an arc occurring.

[0004] An example of such a contactor in a modern vehicle is, for example, a contactor in the electrical connection between an energy storage unit, such as a battery unit of the vehicle, and a charging unit for the energy storage unit of the vehicle. Such a contactor is also called a battery contactor, for example. But other contactors are also known, such as a contactor between an inverter and an energy storage unit or a contactor between a DC charging station and an energy storage unit.

[0005] Since contactors usually have to withstand very high electrical loads, it is not uncommon for the contact surfaces of the contactors to age over their service life due to the opening and closing of the contactors. For this reason, the contact surfaces of the contactors are usually assigned a so-called aging factor, which is ultimately intended to describe the aging state of the contact surfaces of the contactors.

[0006] However, previous methods for determining the aging state of contact surfaces of contactors are inaccurate or incomplete. Summary of the invention

[0007] It is therefore an object of the present invention to provide a method with which the aging state of the contact surface of a contactor can be determined more accurately and more completely.

[0008] This object is achieved by the subject matter of the independent claims. Further aspects and advantages of the invention are described in the dependent claims.

[0009] According to a first aspect of the invention, a method for determining a surface regeneration parameter of a contact surface of a contactor or a contactor, in particular a contactor in a vehicle, is provided. The surface regeneration parameter represents here the regeneration or self-healing of the contact surface of the contactor during the closed state of the contactor. The method according to the first aspect comprises the following steps: determining the current or load current flowing through the closed contactor, determining the duration of the contactor closure, and determining the surface regeneration parameter based on the determined current and the determined duration.

[0010] The method according to the first aspect is at least partially based on the knowledge that the contact surface of the contactor can be regenerated under certain circumstances during the closed state of the contactor. The method according to the first aspect is also based on the knowledge that the regeneration is carried out according to the duration of the closing of the contactor and according to the load current flowing through the closed contactor. The invention is also based on the knowledge that surface regeneration parameters can be described based on the determined load current and the determined duration of the closed contactor. As a result, the actual aging state of the contact surface of the contactor can be estimated more accurately. This is because it becomes understandable to what extent the contact surface can be regenerated in the closed state of the contactor and how this regeneration can be described based on the surface regeneration parameters.

[0011] A preferred embodiment of the method according to the first aspect provides that the surface regeneration parameter is determined based on the determined duration and the load integral of the determined load current. In the context of the present disclosure, the term "load integral" refers to the integral of the square of the load current I over the duration t of the contactor closure. The calculation of the load integral is therefore similar to the calculation of the limit load integral, which is also known as the fuse integral and describes, for example, the triggering behavior of a fuse.

[0012] In another preferred embodiment of the method according to the first aspect, the surface regeneration parameter is also determined as a function of the ambient temperature of the contactor. This particularly preferred embodiment is based in part on the knowledge that the surface regeneration of the contact surface of the contactor depends not only on the load current and the duration of the closed contactor, but also on the ambient temperature of the contactor. For example, it has been found that for the same load integral of load current and duration, the surface regeneration is higher at higher ambient temperatures than at lower ambient temperatures.

[0013] For example, the surface regeneration parameters can be determined based on the functional relationship between the duration, the load current and, if necessary, the ambient temperature of the contactor. For example, these functional relationships can be provided in the form of table values ​​or provided in another way for further processing. For example, it is also possible to determine the so-called aging factor of the contact surface of the contactor, wherein the aging factor represents the aging state of the contact surface of the contactor.

[0014] Therefore, the second aspect of the present invention provides a method for determining the aging factor of the current contactor in the electrical connection, especially the current contactor in the vehicle. Here, the aging factor represents the aging state of the contact surface of the current contactor. The aging factor is also a continuous counter, and the value of the continuous counter is changed according to the opening and closing of the current contactor. According to the method of the second aspect, the differential voltage at both ends of the disconnected current contactor is determined. For example, the differential voltage at both ends of the disconnected current contactor is determined by two separate voltmeters at both ends of the positive line and the negative line of the electrical connection, wherein the difference between the determined voltages represents the differential voltage of the current contactor. Therefore, in particular, the differential voltage is not determined by means of a direct voltage measurement at both ends of the disconnected current contactor by means of an electrical connection, because this will eventually lead to a high-ohmic electrical connection between the two sides of the disconnected current contactor, which should not or cannot happen, because then it is indeed impossible to interrupt the conductive line by disconnecting the contactor.

[0015] The method according to the second aspect further provides that a first additive term for the aging factor is determined based on the determined differential voltage. This can again be done, for example, using table values.

[0016] The method according to the second aspect further provides that the contactor is closed if the current aging factor calculated based on the last known aging factor before closing the contactor and adding the first addition term is below a threshold value. In other words, the first addition term is therefore added to the last current aging factor in order to obtain the current current aging factor. If this current aging factor is below a threshold value, which threshold value represents, for example, an emergency operation threshold value for operating the vehicle, the contactor is closed in the method according to the second aspect. However, on the contrary, if the current aging factor calculated in this way is above this threshold value, the contactor will not be closed.

[0017] The method according to the second aspect further provides for determining a surface regeneration parameter, which represents the regeneration of the contact surface of the contactor during the closed contactor, wherein the surface regeneration parameter is determined based on the load current flowing through the closed contactor and the duration of the contactor closure. As already described in conjunction with the method according to the first aspect, the surface regeneration parameter can be determined based on a table value or the like.

[0018] The method according to the second aspect further provides that a subtractive term for the aging factor is determined as a function of the determined surface regeneration parameter. The subtractive term can in turn be determined as a function of the determined surface regeneration parameter based on a table value or another functional relationship. The subtractive term has a nominally positive value like the first additive term, but is referred to as a subtractive term because, in contrast to the additive term, it nevertheless contributes to reducing the aging factor, as will be explained in more detail later.

[0019] The method according to the second aspect further provides that the load current at the closed contactor is determined immediately before the contactor is opened. The term "immediately before the contactor is opened" is intended to convey that the load current flows through the electrical connection during the closed contactor, but that the load current is not permanently constant, but is reduced, if necessary, by an external control unit, in particular shortly before the contactor is opened, in order in particular to also avoid arcs at the contactor to be opened to the greatest extent possible.

[0020] The method according to the second aspect further provides that a second additive term for the aging factor is determined based on the load current that has been determined immediately before the current contactor is opened. The second additive term for the aging factor is nominally positive like the first additive term for the aging factor, but contributes to increasing the aging factor, as will be shown later. Like the first additive term and the subtractive term, the second additive term can be determined according to a functional relationship or a table value.

[0021] The method according to the second aspect further provides that the current contactor is disconnected, and after the current contactor is disconnected, the current aging factor of the current contactor is determined based on the last known aging factor before the current contactor is disconnected and the second addition term is added and the subtraction term is subtracted. The last known aging factor before the current contactor is disconnected has already taken into account the first addition term, which should describe the aging of the contact surface when the current contactor is closed. By now adding the second addition term and subtracting the subtraction term after the current contactor is disconnected, the current aging factor thus obtained more accurately and more completely represents the aging state of the contact surface of the current contactor. This is because the aging not only when the current contactor is closed (first addition term) but also when the current contactor is disconnected (second addition term) has been taken into account, as well as the regeneration or self-healing of the contact surface that occurs during the closed current contactor (subtraction term).

[0022] The method according to the second aspect therefore determines the aging factor of the contactor more accurately than the known methods according to the prior art, since the surface regeneration of the contact surface(s) taking place in the closed contactor is taken into account by the subtraction term.

[0023] The method according to the second aspect uses essentially the same knowledge as the method according to the first aspect, namely determining the surface regeneration parameter based on the load current flowing during the closed contactor and based on the duration of the contactor closure.

[0024] A preferred embodiment of the method according to the second aspect provides for determining the surface regeneration parameter based on the load integral of the determined load current and the determined duration. The load integral is here again the integral of the square of the load current I over the duration t of the contactor closure.

[0025] Another preferred embodiment of the method according to the second aspect provides that the surface regeneration parameter is determined as a function of the ambient temperature. In this case, the following knowledge is again used: at the same load current and the same duration, the regeneration of the contact surface is greater if the ambient temperature of the contactor is higher.

[0026] Another preferred design of the method according to the second aspect provides that if a short circuit occurs in an electrical connection in the vehicle during the closing of the current contactor, the following steps are performed: determining the short circuit, determining the value of the limit load integral of the automatic cut-out that has interrupted the short circuit, and determining a third additive term for the aging factor based on the determined value of the limit load integral. The third additive term takes into account the additional aging of the contact surface caused by the short circuit in the electrical connection and, like the other two additive terms, can be determined by a functional relationship or a table value based on the determined limit load integral. This preferred design is at least partially based on the following knowledge: for example, the value of the limit load integral for the current monitoring of the high-voltage battery can be 1.5 million A 2 s (ampere squared second), while the value of the limit load integral of the discharge of the capacitor of the EMC filter of the inverter may be 10000A. 2 s (ampere squared seconds). The aging factor can therefore increase differently depending on the value of the limit load integral.

[0027] A particularly preferred embodiment provides that the current aging factor taking into account the short circuit is determined based on the last current aging factor and adding a third addition term. Since, as already described, the last known or current aging factor is calculated by adding the first and second addition terms and subtracting the subtraction term, in this particularly preferred embodiment, the third addition term is now finally added, which should represent the aging of the contact surface caused by the short circuit. Thus, the current aging factor is obtained by adding all three addition terms and subtracting the subtraction term.

[0028] Another preferred embodiment of the method according to the second aspect provides that if the aging factor after adding the first additive term exceeds a warning threshold value that is below the emergency operating threshold value, a notification is made about a vehicle workshop stop for surface regeneration, for example to the driver of the vehicle. This preferred embodiment is based at least in part on the knowledge that if a threshold value that is above the warning threshold value but below the emergency operating threshold value is exceeded, the contact surface of the contactor can be regenerated accordingly, for example by a workshop stop.

[0029] According to a third aspect of the invention, a method for regenerating the contact surface of a contactor, in particular a contactor in a vehicle, is proposed. The method according to the third aspect comprises the following steps: determining that regeneration of the contact surface is required, and regenerating the contact surface by closing the contactor for the duration required for the regeneration. The method according to the third aspect of the invention also makes use of the knowledge that the contact surface of the contactor can be regenerated by the closed contactor and the load current associated therewith, given an appropriate duration of the contactor closure.

[0030] In a preferred embodiment of the method according to the third aspect, a load current flowing through the closed contactor is determined, and a time duration required for the regeneration is determined as a function of the determined load current.

[0031] In another preferred design of the method according to the third aspect, the current contactor is located between the energy storage unit of the vehicle and the charging unit for the energy storage unit, in particular the DCDC charging unit, in the electrical connection, and when the contactor is closed, the contact surface is regenerated by starting the charging process of the energy storage unit.

[0032] In a particularly preferred embodiment of the method according to the third aspect, a notification is issued, according to which the charge state of the energy storage unit should be adapted accordingly, if the duration of the charging process required for regeneration is greater than the current maximum possible charging duration, which is determined according to the current charge state of the energy storage unit. In other words, it is conceivable that, although regeneration of the contact surface of the contactor is necessary, the charging duration required for regeneration is greater than the current maximum possible charging duration, because the energy storage unit is, for example, still too full at the time when regeneration will be required, and thus cannot be charged over the entire required duration that will be necessary for regenerating the contact surface. In this case, the notification output indicates, for example, that the driver of the vehicle or a third party still needs to empty the energy storage unit by a predetermined value, in that the driver of the vehicle or a third party, for example, drives the minimum road section without charging the vehicle. The next charging process will then take place in a workshop, where, due to the additionally emptied energy storage unit, the vehicle can now be charged for the charging duration required for regeneration.

[0033] Preferred embodiments of the method according to the first aspect are preferred embodiments of the method according to the second aspect and / or according to the third aspect, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Other features and tasks of the present invention will become apparent to those skilled in the art by practicing the present teachings and considering the accompanying drawings, wherein:

[0035] Figure 1 A schematic diagram showing an electrical connection with a contactor,

[0036] Figure 2 A schematic illustration showing a flow chart for carrying out the method according to the invention according to the first aspect,

[0037] Figure 3 a schematic diagram showing a flow chart for carrying out the method according to the invention according to the second aspect,

[0038] Figure 4Shown for execution Figure 3 A schematic illustration of a flow chart of one specific embodiment of the method according to the invention,

[0039] Figure 5 Shown for execution Figure 3 A schematic illustration of a flow chart of a further specific embodiment of the method according to the invention,

[0040] Figure 6 a schematic diagram showing a flow chart for carrying out the method according to the invention according to the third aspect, and

[0041] Figure 7 Shown for execution Figure 6 FIG. 1 is a schematic illustration of a flow chart of one specific embodiment of the method according to the invention. DETAILED DESCRIPTION

[0042] First, you should refer to Figure 1 , Figure 1 An electrical connection 10 between an energy storage unit 12 and a charging unit 14 for the energy storage unit 12 is shown. Figure 1 In the specific example, the electrical connection 10 is an electrical connection in the vehicle, but in other embodiments not shown, it may also be other electrical connections. The energy storage unit 12 may, for example, be a battery unit for a battery-powered vehicle. However, the energy storage unit 12 may also be other energy storage units as would be present, for example, in the case of a fuel cell-powered vehicle. The charging unit 14 may be a charging column for charging the energy storage unit 12, such as a DCDC charging column. However, the charging unit 14 may also be an inverter unit of an on-board charging unit of the vehicle. It is important that the charging unit 14 can be used to charge the energy storage unit 12.

[0043] As is customary for such electrical connections, the electrical connection 10 between the charging unit 14 and the energy storage unit 12 has two electrical lines 16 , 18 , wherein one of the two lines 16 , 18 connects the two positive poles of the charging unit 14 and the energy storage unit 12 , and the other of the two lines 16 , 18 connects the two negative poles of the charging unit 14 and the energy storage unit 12 .

[0044] So-called current contactors or contactors 20 for short are arranged in each of the two electrical lines 16, 18. The contactors 20 are electrically or electromagnetically operated or operable switches which are designed in particular for high electrical powers and have two predetermined switch positions. Figure 1 In the open first switching position of the contactor 20 shown in FIG. , the corresponding electrical lines 16 , 18 are interrupted, so that no current can flow between the charging unit 14 and the energy storage unit 12 . In the closed second switching position of the contactor 20 ( FIG. 1 ), the corresponding electrical lines 16 , 18 are interrupted, so that no current can flow between the charging unit 14 and the energy storage unit 12 . Figure 1), the corresponding electrical lines 16 , 18 are closed so that current, in particular load current, can flow between the charging unit 14 and the energy storage unit 12 .

[0045] So external Figure 1 As shown in FIG. 1 , there is a first voltmeter 22 between the lines 16, 18 and a second voltmeter 24 between the lines 16, 18. The two voltmeters 22, 24 are arranged on opposite sides of the contactor 20. With the aid of the voltmeters 22, 24, the voltage difference between the lines 16, 18 can be measured upstream and downstream of the contactor 20. By comparing the two measured voltage differences, the differential voltage across the disconnected protection device 20 can be determined, as is known to a person skilled in the art in the case of such a device.

[0046] So external Figure 1 As shown in FIG. 2 , an ammeter 25 is also present. With the aid of the ammeter 25 , it is possible to measure the load current flowing between the units 12 and 14 via the closed contactor 20 .

[0047] The contactor 20 has one or more contact surfaces 26, which are in contact in an electrically conductive and voltage-carrying manner in the closed state of the contactor 20, so that in the closed state of the contactor 20, the load current can ultimately flow between the units 12 and 14 via the lines 16, 18. As already mentioned in detail, the contact surfaces 26 of the contactor 20 are subject to material-dependent aging. Due to the high electrical powers that the current contactor 20 has to conduct, aging of the contact surfaces 26 can occur. However, as already mentioned several times within the scope of the present disclosure, it is entirely possible that in the closed state of the contactor 20, the contact surfaces 26 can be subject to self-healing, so that any aging of the contact surfaces 26 that may occur can be partially or even completely compensated.

[0048] exist Figures 2 to 7 The following method is proposed, with which it is possible to determine the regeneration of the contact surface 26 of the contactor 20 in the closed state of the contactor 20 and to map the regeneration by means of a so-called surface regeneration parameter. The surface regeneration parameter can then be taken into account, for example, when determining an aging factor of the contact surface 26, in order to determine a more accurately adapted current aging state of the contact surface 26 for regeneration, the aging factor reflecting the current aging state of the contact surface 26.

[0049] Should refer to Figure 2 , Figure 2 A flow chart for carrying out a method for determining a surface regeneration parameter of a contact surface 26 of a contactor 20 is shown, wherein the contactor 20 is arranged, for example, in combination with Figure 1 An electrical connection 10 has been shown.

[0050] The method starts at step 200 .

[0051] In step 202 , the method determines the load current which flows between the two units 12 , 14 when the contactor 20 is closed. This is done by means of an ammeter 25 .

[0052] Furthermore, in step 204, the method determines the duration during which the contactor 20 is closed.

[0053] Based on the determined duration of the closing of the contactor 20 and based on the load current determined when the contactor 20 is closed, a surface regeneration parameter is determined in step 206. The determination of the surface regeneration parameter can be determined, for example, based on the load integral of the determined duration and the determined load current, and can be provided, for example, by a functional relationship or a table value. Optionally, the surface regeneration parameter is also determined taking into account the ambient temperature of the contactor 20, because it has been found that, with the same load current and the same duration, the regeneration of the contact surface 26 may be greater at a higher ambient temperature. The ambient temperature can also be part of the table record, so that ultimately there is a characteristic curve family for the surface regeneration parameter according to the ambient temperature, the determined duration of the closing of the contactor 20 and the determined load current.

[0054] Now, when determining the aging factor of the contact surface 26 of the contactor 20, the surface regeneration parameter determined in this way can also be taken into account, as shown below in conjunction with Figures 3 to 5 Described in more detail.

[0055] Figure 3The method is used to determine the aging factor of the contact surface 26 of the contactor 20. The aging factor represents the aging state of the contact surface 26 of the contactor 20 and is basically a continuous counter, the value of which is changed according to the opening and closing of the contactor 20. Therefore, for example, when the current contactor 20 is opened or closed, the aging factor can be set to high. However, the aging factor can also be reduced by a predetermined value. Then, that is, when the aging of the contact surface 26 does not occur at all in the end, but the opposite fact of aging occurs, that is, the surface regeneration of the contact surface 26. The name "aging" refers to, for example, the roughening or material erosion or corrosion of the contact surface 26. This corrosion of the contact surface 26 may be carried out in the following way, that is, due to the high electrical power that the current contactor 20 must conduct, an arc occurs between the contact surfaces 26 and material corrosion occurs on the contact surface 26. The material corrosion on the contact surface 26 causes: the functionality of the current contactor 20 may no longer exist from a specific state. In contrast, the term "regeneration" refers to the self-healing of the contact surface 26, which takes place in the closed state of the contactor 20 under certain conditions, in particular depending on the load current and on the duration of the closure of the contactor 20. The regeneration of the contact surface 26 leads to at least partial smoothing of the contact surface 26, thereby counteracting erosion processes, hence the term self-healing. For example, the smoothing of the contact surface 26 takes place in that the contact surface 26 is heated for a corresponding duration at a corresponding load current and is thereby automatically smoothed.

[0056] The method for determining or determining an aging factor of the contactor 20 begins at step 300 .

[0057] In step 302, the differential voltage across the open contactor 20 is determined. Figure 1 The two voltmeters 22, 24 depicted make this determination.

[0058] Based on the determined differential voltage across the open contactor (step 302), a first additive term for the aging factor is determined in step 304. For example, the first additive term may be determined based on a functional relationship or a table value according to the determined differential voltage.

[0059] In the next step 306, the current aging factor is determined. The current aging factor is an updated aging factor. The current aging factor is obtained from the last current aging factor before closing the contactor 20 and adding the first additive term, which reproduces the aging of the contact surface 26 caused by the closing of the contactor 20.

[0060] In the next step 308, it is checked whether the current aging factor thus determined is greater than a threshold value. The threshold value may be, for example, an emergency operation threshold value. If the current aging factor thus calculated is greater than the threshold value, an emergency operation is triggered in step 309. The emergency operation may, for example, include that the vehicle in which the contactor 20 is installed can no longer be driven. However, if it is determined in step 308 that the current aging factor thus determined is not greater than the threshold value, the steps in the dashed box 310 are processed.

[0061] In block 310 , the contactor 20 is now first closed in step 312 . For the reasons already mentioned, the closing of the contactor 20 contributes to the aging of the contact surface 26 , wherein the resulting current aging state of the contact surface 26 is represented by the current aging factor already determined in step 306 .

[0062] In the next step 314, since the contactor 20 is closed and the above-mentioned regeneration process of the contact surface 26 occurs, the surface regeneration parameters are determined. Figure 2 The described determination of the load current in the case of a closed contactor 20 , the determination of the duration of the closing of the contactor 20 and, if applicable, the ambient temperature of the contactor 20 are determined.

[0063] In the next step 316, a subtraction term for the aging factor is determined based on the determined surface regeneration parameter. The subtraction term can in turn be present as a table value depending on the surface regeneration parameter. The subtraction term for the aging factor is nominally a positive value, but as will be shown later, the subtraction term will reduce the aging factor because it is deducted or subtracted from the last current aging factor. This subtraction expresses that the current aging state is partially or completely reset due to the mentioned surface regeneration, because the self-healing of the contact surface 26 is carried out within the corresponding duration under the corresponding load current.

[0064] After the subtraction term has now been determined in step 316, in the next step 318, the load current is determined immediately before opening the contactor 20. The load current immediately before opening the contactor 20 will generally be smaller than the load current during the duration of the closed contactor 20. This is because when opening the contactor 20, the maximum load current, which is used, for example, for charging the energy storage unit 12 or provided by the energy storage unit 12, should be prevented from flowing via the contact surface 26 when opening the contactor 20. This would therefore contribute to a disproportionately high erosion of the contact surface 26, which is undesirable or should be avoided.

[0065] Based on the determination of the load current immediately before opening the contactor (see step 318), a second additive term for the aging factor is now determined in step 320. Exactly like the first additive term, the second additive term contributes to the aging of the contact surface 26. This is because even in the event of opening of the contactor 20 and a possible arc on the contact surface 26, erosion and thus aging of the contact surface 26 can occur.

[0066] In the next step 322 , the contactor 20 is now opened.

[0067] In the next step 324, the current aging factor is determined. The current aging factor is an aging factor that characterizes the aging state after the closing and disconnecting contactor 20 and after the contactor 20 is disconnected again. The current aging factor is determined based on the last known aging factor before disconnecting the contactor 20 and adding the second addition term and subtracting the subtraction term. Since the last known aging factor before disconnecting the contactor 20 already takes into account the first addition term, in the process of closing and subsequently disconnecting the contactor 20, the two addition terms are finally added to the last known aging factor before the last closing of the contactor 20 and the subtraction term is additionally subtracted. The current aging factor determined in this way therefore takes into account the aging of the contact surface 26 caused by the closing and disconnection of the contactor 20 on the one hand, and also takes into account the surface regeneration of the contact surface 26 performed during the closed contactor 20.

[0068] Now you should refer to Figure 4 , Figure 4 Show Figure 3 A design scheme of the method. Figure 3 As mentioned in steps 306 and 308 , an aging factor is calculated taking into account the first additive term and compared with a threshold value.

[0069] exist Figure 4 In this design, there are ultimately two thresholds: a warning threshold and an emergency operation threshold. The warning threshold is below the emergency operation threshold.

[0070] In step 400, the step may first check whether the current aging factor determined in step 306 is greater than a warning threshold value, after or instead of step 308. If this is not the case, i.e. if the warning threshold value is not exceeded, a combined Figure 3If, however, the result of step 400 is that the current aging factor determined from step 306 is greater than the warning threshold, a query is made in step 402 whether the current aging factor is less than the emergency operation threshold. If the query in 402 shows that the aging factor determined from step 306 is not less than the emergency operation threshold, an emergency operation of the vehicle is performed as already described in connection with step 309. If, however, in the case of step 402 the query shows that the current aging factor determined in step 306 is less than the emergency operation threshold, a notification is made in step 404 about a vehicle workshop stop for surface regeneration of the contact surface 26.

[0071] Therefore, according to Figure 4 The two-stage threshold query ultimately does not immediately trigger the emergency operation of the vehicle, but instead outputs a notification if the current aging factor is less than the emergency operation threshold but greater than the warning threshold: surface regeneration of the contact surface 26 of the contactor 20 is possible, for example with the aid of a vehicle workshop stop.

[0072] Now you should refer to Figure 5 , Figure 5 describe Figure 3 Another embodiment of the method.

[0073] exist Figure 5 In one embodiment, a short circuit which may occur while the contactor 20 is closed is checked.

[0074] For this purpose, it is first determined in step 500 whether a short circuit has occurred in an electrical connection, in particular in an electrical connection of a vehicle, while contactor 20 is closed.

[0075] If no short circuit occurs, the final execution Figure 3 Steps 314 to 320 of the dotted line frame, and disconnecting the current contactor 20 (step 322), and according to Figure 3 Step 324 calculates the current aging factor.

[0076] However, if a short circuit has been determined during the closed contactor 20 in step 500, then steps 314 to 320 are first processed. However, in addition, the limiting load integral of the automatic fuse of the component in the vehicle that has interrupted the short circuit is determined in step 502. Therefore, depending on which component in the vehicle caused the short circuit, different values ​​of the limiting load integral of the automatic fuse associated with the component are obtained.

[0077] In step 504, a third additive term is determined based on the value of the limiting load integral of the automatic cutout that has interrupted the short circuit. The third additive term can in turn be available based on a table value or a functional relationship depending on the determined value of the limiting load integral.

[0078] As also in the case of a short circuit that has not occurred, the current contactor 20 is now opened in step 322. However, in the subsequent step 506, compared to step 324, the current aging factor is taken into account taking into account the third additive term that has already been determined in conjunction with step 504. The difference between steps 506 and 324 in the calculation of the current aging factor is therefore ultimately the third additive term, which takes into account the aging of the contact surface 26 that has occurred due to the short circuit that is present in the closed state of the contactor 20.

[0079] Should refer to Figure 6 , Figure 6 A further method is described which uses the knowledge of a possible regeneration of the contact surface 26 during the closing of the contactor 20 .

[0080] Specifically, Figure 6 Description for regeneration e.g. Figure 1 A method of electrically connecting the contact surface 26 of the contactor 20 in the embodiment of the present invention.

[0081] The method starts at step 600 .

[0082] In step 602, a required regeneration of the contact surface 26 of the contactor 20 is determined. The required regeneration of the contact surface 26 may be determined, for example, in that the aging factor exceeds a threshold value.

[0083] After the required regeneration has been determined in step 602, the contact surface 26 is regenerated in a subsequent step 604, wherein the contactor 20 is closed for the predetermined duration required for the regeneration. The duration required for the regeneration of the contact surface 26 can again be based on table values ​​and ultimately use the relationship between the load current, the surface regeneration parameters and, if necessary, the ambient temperature of the contactor 20, as has already been mentioned several times in conjunction with the present invention.

[0084] Finally, you should refer to Figure 7 , Figure 7 Show Figure 6 A design scheme for the method.

[0085] exist Figure 7 In step 700 , a time duration required for regeneration of the contact surface 26 is determined as a function of the load current when the contactor 20 is closed.

[0086] In step 702, a check is performed to determine whether the duration required for the regeneration is greater than the currently maximum possible charging duration of the energy storage unit 12 (see Figure 1If the duration required for the regeneration is not greater than the currently maximum possible charging duration determined based on the current charge state of the energy storage unit 12 , then in step 704 the energy storage unit 12 is charged for the duration required for the regeneration.

[0087] However, if it is determined in step 702 that the duration required for the regeneration is greater than the current maximum possible charging duration of the energy storage unit 12, then in step 706 it is communicated that the charge state of the energy storage unit 12 should be adapted accordingly. In other words, the energy storage unit 12 must be discharged more in order to increase the maximum possible charging duration. In particular, the maximum possible charging duration must then be at least as long as the duration required for the regeneration. This ensures that the energy storage unit 12 can be charged for a sufficiently long time in order to be able to carry out the required regeneration of the contact surface 26 while the energy storage unit 12 is being charged.

Claims

1. A method for determining a surface regeneration parameter of a contact surface (26) of a contactor (20), in particular a contactor (20) in a vehicle, wherein the surface regeneration parameter represents a regeneration of the contact surface (26) of the contactor (20) during a closed state of the contactor (20), wherein the method comprises the following steps: - determining the load current flowing through the closed contactor (20), - determining the duration of the closure of the contactor (20), and - determining the surface regeneration parameter based on the determined load current and the determined duration. 2 . The method of claim 1 , wherein the surface regeneration parameter is determined based on the determined duration and a load integral of the determined load current.

3. The method according to any of the preceding claims, wherein the surface regeneration parameter is determined as a function of the ambient temperature of the contactor.

4. A method for determining an aging factor of a contact surface of a contactor (20), in particular a contactor (20) in a vehicle, wherein the aging factor represents the aging state of the contact surface (26) of the contactor (20), wherein the aging factor is a continuous counter, the value of which is changed according to the opening and closing of the contactor (20), and wherein the method comprises the following steps: - determining the differential voltage across the open contactor (20), - determining a first additive term for the aging factor based on the determined differential voltage, - closing the contactor (20) if the current aging factor calculated based on the last known aging factor before closing the contactor and adding the first added term is below a threshold value, - determining a surface regeneration parameter, which represents the regeneration of a contact surface (26) of the contactor (20) during the closing of the contactor (20), wherein the surface regeneration parameter is determined based on a load current flowing through the closed contactor (20) and a duration of the closing of the contactor (20), - determining a subtraction term for said aging factor as a function of the determined surface regeneration parameter, - determining the load current at the closed contactor (20) immediately before opening said contactor (20), - determining a second additive term for the aging factor based on the load current which has been determined immediately before opening the contactor (20), - opening the contactor (20), and After the contactor (20) is opened, the current aging factor of the contactor (20) is determined based on the last known aging factor before the contactor is opened and the second addition term is added and the subtraction term is subtracted. The method of claim 4 , wherein the surface regeneration parameter is determined based on the determined duration and a load integral of the determined load current.

6. The method according to any one of claims 4 to 5, wherein the surface regeneration parameters are determined as a function of the ambient temperature.

7. The method according to any one of claims 4 to 6, wherein if a short circuit occurs in an electrical connection in the vehicle during the closed contactor (20), the following steps are performed: - determining said short circuit, - determine the value of the limiting load integral of the automatic cut-out which has interrupted the short circuit, and - determining a third additive term for the aging factor based on the determined value of the limit load integral.

8. The method according to claim 7, further comprising: - Based on the last current aging factor and adding the third addition term, calculating the current aging factor taking the short circuit into account. 9 . The method according to claim 4 , wherein a notification regarding a vehicle workshop stop for surface regeneration is made if the aging factor after adding the first additive term exceeds a warning threshold value below an emergency operating threshold value.

10. A method for regenerating a contact surface (26) of a contactor (20), in particular a contactor (20) in a vehicle, wherein the method comprises the following steps: - determining that regeneration of the contact surface (26) is required, and - regenerating the contact surface (26) by closing the contactor (20) for the duration required for regeneration.

11. The method according to claim 10, wherein a load current flowing through the closed contactor (20) is determined and a required duration for the regeneration is determined as a function of the determined load current.

12. A method according to any one of claims 10 to 11, wherein the current contactor (20) is arranged in the electrical connection (10) between the vehicle's energy storage unit (12) and a charging unit (14) for the energy storage unit (12), and regeneration of the contact surface (26) is performed when charging the energy storage unit (12).

13. The method according to claim 12, wherein a notification is issued if the required duration is greater than the currently maximum possible charging duration, which is determined based on the current charging state of the energy storage unit (12), based on which the charging state of the energy storage unit (12) should be adapted accordingly.

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