Method for operating switching arrangement of energy storage system in vehicle

Abstract

The present application relates to a method for operating a switching arrangement of an energy storage system in a vehicle, in particular a computer system, comprising processing circuitry configured to: provide a characterization model for each of a plurality of contactors of the switching arrangement, each contactor is configured to connect and disconnect an associated battery pack of an energy storage system of a vehicle by closing and opening, respectively, the characterization model defining contactor wear for the opening of the contactor with respect to a plurality of system parameters including at least a current and a voltage during the opening of the contactor, determining the system parameter during operation of the switching arrangement, estimating contactor wear for each of the contactors by applying the determined system parameter to the corresponding characterization model; -controlling the sequence of contactor disconnection in response to the estimated contactor wear, and / or predicting contactor maintenance or contactor replacement in response to the estimated contactor wear.

Description

Technical Field

[0001] The present disclosure generally relates to operational management of a battery pack in an energy storage system of a vehicle. In a particular aspect, the present disclosure relates to a method for controlling a switch arrangement of an energy storage system of a vehicle. The present disclosure may be applicable to heavy vehicles such as trucks, buses, and construction equipment, among other vehicle types. Although the present disclosure may be described with respect to a particular vehicle, the present disclosure is not limited to any particular vehicle. Background Art

[0002] A vehicle typically includes an engine for propelling the vehicle. The engine may be an internal combustion engine powered by, for example, a liquid or gaseous fuel, or it may be an electric motor powered by electricity. Furthermore, there are hybrid solutions where the vehicle is propelled by both an internal combustion engine and an electric motor. Either way, an energy storage device is used to store the energy required to propel the vehicle. The energy storage device may also be used to power auxiliary loads in the vehicle.

[0003] For many vehicles, an energy storage device is included in an energy storage system, where the energy storage system is configured to power the motor used to propel the vehicle as well as any auxiliary loads. For example, for an electric vehicle, the energy storage device may be a battery or battery pack that is configured to operate the motor as well as the electric auxiliary equipment. The motor and / or the electric auxiliary equipment may generally be referred to as a load. Several batteries or several battery cells connected in series and / or in parallel may be grouped into a battery pack. The battery pack needs to be charged regularly and then electrically connected to an electrical energy source, for example via a plug connected directly to the grid or by an on-board charger. Such a charger may generally be referred to as a power source.

[0004] In many applications, several battery packs are included in an energy storage system (sometimes referred to as a multi-battery pack system) by being connected in parallel to a common traction voltage bus (or a common traction power bus). The load and / or power source are also connected to the common traction voltage bus. Thus, the power supplied can be adjusted based on the number of battery packs, and / or higher power requirements of the vehicle can be met. Typically, each battery pack is associated with a switch or contactor so that the battery pack can be connected and disconnected relative to the common traction voltage bus and the load and / or power source. However, each time the state of the contactor changes from closed to open, or vice versa, the contactor is subject to mechanical and electrical wear in the form of contactor wear.

[0005] The above-mentioned contactor wear may lead to contactor failure. In particular, premature contactor failure of a single contactor is undesirable because sometimes more than just the failed contactor needs to be replaced, which may be very troublesome. Summary of the invention

[0006] According to a first aspect of the present disclosure, a computer system including a processing circuit is provided. The processing circuit is configured to: provide a characterization model for each of a plurality of contactors of a switch arrangement, each contactor being configured to connect and disconnect an associated battery pack of an energy storage system of a vehicle by closing and opening, respectively, the characterization model defining contactor wear for contactor disconnection with respect to a plurality of system parameters, the system parameters including at least current and voltage during contactor disconnection; determine the system parameters during operation of the switch arrangement; estimate the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; control the order of contactor disconnection in response to the estimated contactor wear, and / or predict contactor maintenance or contactor replacement in response to the estimated contactor wear.

[0007] The first aspect of the present disclosure may seek to overcome problems associated with a shortened life of a switch arrangement because the estimated contactor wear due to contactor disconnection is improved by applying a characterization model. Thus, the order in which the contactors are disconnected may be controlled in response to the estimated contactor wear, thereby improving the distribution of contactor wear in the contactors in the switch arrangement, and / or contactor maintenance or contactor replacement may be predicted in response to the estimated contactor wear. Thus, contactor failures due to excessive contactor wear of a single contactor may be avoided. Therefore, the technical advantages of the first aspect of the present disclosure may include extending the life of the switch arrangement. That is, by implementing a characterization model using system parameters of each of the contactors, an improved estimate of contactor wear is provided, and an improved estimate of contactor wear may be implemented in a control strategy associated with the order in which the contactors are disconnected and / or in a maintenance strategy for the contactors. It should be noted that the system parameters including at least the current and voltage during contactor disconnection refer to the current and voltage on the corresponding contactor during contactor disconnection.

[0008] In some examples, including in at least one preferred example, preferably, the processing circuit is further configured to: receive measurement data from a plurality of sensors of the energy storage system, wherein the measurement data includes the system parameters. Technical advantages may include the use of reliable data and efficient data processing and communication. The plurality of sensors may, for example, include a current sensor and / or a voltage sensor for each of the contactors. Such current sensors and voltage sensors are typically arranged to measure the current and voltage on the corresponding contactors, respectively.

[0009] In some examples, including in at least one preferred example, preferably, the processing circuit is also configured to: identify multiple parallel-arranged battery packs connected to a common traction voltage bus of the energy storage system, and identify associated contactors to the multiple parallel-arranged battery packs, wherein the order in which the contactors are disconnected is controlled for all of the multiple parallel-arranged battery packs until no battery packs are connected to the common traction voltage bus. Technical advantages can include improved control strategies related to the order in which contactors are disconnected. For example, the last contactor to be disconnected (i.e., the contactor that is disconnected after no battery packs are connected to the common traction voltage bus) can be specifically selected based on estimated contactor wear using a characterization model.

[0010] The battery packs of the energy storage system are preferably battery packs arranged in parallel. Thus, the processing circuit of the first aspect may be described as being configured to operate a switch arrangement of an energy storage system, the energy storage system comprising a plurality of battery packs arranged in parallel, and the switch arrangement comprising an associated contactor for each battery pack, the contactor being configured to connect the battery pack to the common traction voltage bus by closing, and to disconnect the battery pack from the common traction voltage bus by opening.

[0011] In some examples, including in at least one preferred example, preferably, the processing circuit is also configured to: after controlling the order of disconnection of the contactor, connect the battery pack to the common traction voltage bus by closing the contactor, and thereafter: alternately connect and disconnect the battery pack from the common traction voltage bus, wherein the order of controlling the disconnection of the contactor is performed for each disconnection. Technical advantages may include improving control strategies related to the order of opening and closing of contactors. For example, in each disconnection or disconnection sequence of the battery pack from the common traction voltage bus, all battery packs are disconnected until no battery pack is connected to the common traction voltage bus. In addition, in each connection or connection sequence of the battery pack to the common traction voltage bus, all battery packs may be connected until all battery packs are connected to the common traction voltage bus.

[0012] In some examples, including at least one preferred example, preferably, the processing circuit is further configured to: determine the accumulated contactor wear of each of the contactors by applying the characterization model to each of the contactors during each contactor disconnection. Technical advantages can include improved estimation of contactor wear.

[0013] In some examples, including in at least one preferred example, preferably, the system parameters also include at least one of the following: temperature, inductance, height and contactor design during contactor disconnection. Technical advantages may include improved estimates of contactor wear. That is, by including additional parameters in the characterization model in addition to the current and voltage during contactor disconnection, the estimate of contactor wear during contactor disconnection can be improved. In other words, in addition to including the contactor current and voltage when the contactor is disconnected, contactor temperature, contactor inductance, height and / or contactor design can also be implemented in the characterization model. It should be understood that the system parameters of a particular contactor are usually determined immediately before disconnecting the contactor. Since height is a pressure-related parameter, and since pressure may affect contactor wear when the contactor is disconnected (e.g., related to the formation and extinguishing of an arc), pressure or atmospheric pressure may be used instead of height.

[0014] In some examples, including in at least one preferred example, preferably, the characterization model defines the contactor wear as a function of the plurality of system parameters, the system parameters including at least current and voltage during contactor disconnection, and additionally including a third system parameter, the third system parameter being at least one of: temperature during contactor disconnection, inductance, height, and contactor design. Technical advantages may include improved estimation of contactor wear.

[0015] In some examples, including at least one preferred example, preferably, the characterization model is defined by the following formula: CW = A*I+B*V+C*X Where CW is the wear of the contactor, I is the current on the contactor, V is the voltage on the contactor, X is a third system parameter when the contactor is open, such as temperature, and A, B, and C are constants. Technical advantages may include improved estimates of contactor wear.

[0016] In some examples, including at least one preferred example, preferably, the characterization model includes a function y=f(x) for each system parameter. Each function f(x) can be defined, for example, as f(x)=A*x, where A is determined during parameterization (performed by characterization testing described later), and x is a system parameter.

[0017] In some examples, including in at least one preferred example, preferably, the processing circuit is also configured to: in response to the estimated contactor wear, control the order of contactor disconnection in a manner that takes into account the contactor wear during subsequent disconnections of the contactor and uses the contactor wear to distribute the contactor wear among the contactors. Technical advantages may include improved control strategies related to the order of contactor disconnection. For example, and with reference to the aforementioned disconnection or disconnection sequence of the battery pack from the common traction voltage bus, the contactor can be disconnected in a manner that takes into account the accumulated contactor wear during the control of the order of contactor disconnection and uses the accumulated contactor wear to distribute additional contactor wear among the contactors. In other words, the processing circuit can also be configured to track the contactor wear or accumulated contactor wear of each contactor.

[0018] It should be noted that the common traction voltage bus can be electrically connected to at least one load, such as, for example, a traction motor of a vehicle. Thus, the battery pack can provide power to the load. Thus, the processing circuit can be configured to connect the battery pack to the load by closing the contactors in the aforementioned controlled sequence, and disconnect the battery pack from the load by opening the contactors.

[0019] In some examples, including in at least one preferred example, preferably, the processing circuit is also configured to: control the order of contactor disconnection in response to the estimated contactor wear in a manner that the contactor other than the contactor with the highest contactor wear is disconnected as the last contactor. Technical advantages may include extending the life of the switch arrangement. That is, by not disconnecting the contactor with the highest contactor wear last, the contactor will not suffer from the relatively high contactor wear associated with the last disconnection, and thereby a single contactor failure due to contactor wear can be avoided or at least extended. Referring to the aforementioned example of controlling the order of contactor disconnection for all multiple battery packs arranged in parallel until no battery packs are connected to a common traction voltage bus, the last contactor to be disconnected refers to the contactor that results in no battery packs being connected to the common traction voltage bus after disconnection.

[0020] The contactor wear mentioned herein can be mechanical wear and / or electrical wear. The electrical wear of the contactor is usually higher than mechanical wear, and is therefore more significant for determining the contactor wear that affects the life of the contactor. Electrical wear may, for example, originate from an arc in the air gap of a non-closed contactor. When the voltage on the air gap exceeds the breakdown voltage (3 kV / mm) of air or when the inductive circuit is destroyed due to the change of the current that the inductor hinders passing through it, an arc usually occurs. When the contactor is disconnected under load, since the air gap is initially zero, the electrical breakdown voltage is usually exceeded. The resistivity of the resulting arc is low, which means that the arc will last for a short time before it is interrupted. When the contactor is closed, on the other side, the breakdown voltage is usually exceeded just before the contactor reaches a fully closed state, thereby generating a small arc.

[0021] Therefore, the wear of the contactor when disconnected may be at least partially caused by the formation of arcs. The effect of such arcs on contactor wear can be evaluated in an advantageous manner by applying a characterization model of system parameters. Since the formation of arcs may be due to residual energy or residual inductance remaining in the energy storage system (e.g., on the common traction voltage bus) after the load is turned off, the residual energy or residual inductance may be included in the multiple system parameters. In a scenario where all battery packs of the energy storage system (disconnected by contactors) are disconnected from the common traction voltage bus so that no battery pack is connected to the common traction voltage bus, the arc will be particularly prominent, especially for the last disconnected contactor. By applying a characterization model to estimate contactor wear, and controlling the order of contactor disconnection and battery pack disconnection in response to such estimated contactor wear, for example, by controlling which contactor is disconnected last, the impending or future contactor wear can be better distributed between the contactors. For example, this can be achieved by changing or rotating the last disconnected contactor in a manner that takes into account the accumulated contactor wear in the contactor based on the characterization model. As previously mentioned, when referring to the last disconnection of the contactors, the last battery pack is disconnected from the common traction voltage bus, and after such disconnection, no battery pack is connected to the common traction voltage bus (ie, all contactors are open).

[0022] According to a second aspect of the present disclosure, a switch arrangement for an energy storage system for a vehicle is provided. The energy storage system includes a plurality of battery packs arranged in parallel, and the switch arrangement includes an associated contactor for each battery pack, the contactor being configured to connect and disconnect the battery pack by closing and opening, respectively. The switch arrangement also includes a control unit, the control unit being configured to: provide a characterization model for each of the contactors, the characterization model defining contactor wear for contactor disconnection with respect to a plurality of system parameters, the system parameters including at least current and voltage during contactor disconnection; determine the system parameters during operation of the switch arrangement; estimate the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; control the order of contactor disconnection in response to the estimated contactor wear, and / or predict contactor maintenance or contactor replacement in response to the estimated contactor wear. The second aspect of the present disclosure may seek to solve the same problem as described for the first aspect of the present disclosure. Therefore, the effects and features of the second aspect of the present disclosure are largely similar to those described above in conjunction with the first aspect of the present disclosure. The examples and disclosures mentioned with respect to the first aspect of the disclosure are largely compatible with the second aspect of the disclosure, and vice versa. For example, the energy storage system comprises a common traction voltage bus as described with reference to the first aspect of the disclosure, and the control unit is configured to connect and disconnect the battery pack from the common traction voltage bus by closing and opening, respectively. The control unit may, for example, comprise the processing circuit described in the first aspect of the disclosure or be included in the processing circuit.

[0023] According to a third aspect of the present disclosure, a vehicle is provided, the vehicle comprising the computer system of the first aspect of the present disclosure or the switch arrangement of the second aspect of the present disclosure. The third aspect of the present disclosure may seek to solve the same problems as described for the first to second aspects of the present disclosure. Therefore, the effects and features of the third aspect of the present disclosure are largely similar to those described above in conjunction with the first to second aspects of the present disclosure. The vehicle may, for example, include an energy storage system comprising a plurality of battery packs arranged in parallel as described above.

[0024] According to a fourth aspect of the present disclosure, a computer-implemented method is provided. The method includes: providing a characterization model for each of a plurality of contactors of a switch arrangement by a processing circuit of a computer system, each contactor being configured to connect and disconnect an associated battery pack of an energy storage system of a vehicle by closing and opening, respectively, the characterization model defining contactor wear for contactor disconnection with respect to a plurality of system parameters, the system parameters at least including current and voltage during contactor disconnection; determining the system parameters by the processing circuit during operation of the switch arrangement; estimating the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model by the processing circuit; controlling the order of disconnection of the contactors by the processing circuit in response to the estimated contactor wear, and / or predicting contactor maintenance or contactor replacement by the processing circuit in response to the estimated contactor wear. The fourth aspect of the present disclosure may seek to solve the same problem as described for the first to third aspects of the present disclosure. Therefore, the effects and features of the fourth aspect of the present disclosure are largely similar to those described above in conjunction with the first to third aspects of the present disclosure.

[0025] In some examples, including in at least one preferred example, preferably, the method further comprises: receiving, by the processing circuit, measurement data from a plurality of sensors of the energy storage system, wherein the measurement data comprises the system parameters. Technical advantages may include the use of reliable data and efficient data processing and communication, as described for the first aspect of the disclosure.

[0026] In some examples, including at least one preferred example, preferably, the method further comprises: identifying, by the processing circuit, a plurality of parallel-arranged battery packs connected to a common traction voltage bus of the energy storage system, and identifying, by the processing circuit, contactors associated with the plurality of parallel-arranged battery packs, wherein the order in which the contactors are disconnected is controlled for all of the plurality of parallel-arranged battery packs until no battery pack is connected to the common traction voltage bus. Technical advantages may include improving control strategies related to the order in which contactors are disconnected, as described with respect to the first aspect of the present disclosure.

[0027] In some examples, including in at least one preferred example, preferably, the method further comprises: determining, by the processing circuit, the accumulated contactor wear of each of the contactors by applying the characterization model to each of the contactors during each contactor disconnection. Technical advantages may include improved estimation of contactor wear, as described for the first aspect of the disclosure.

[0028] In some examples, including in at least one preferred example, preferably, the characterization model defines the contactor wear as a function of the plurality of system parameters, the system parameters at least including current and voltage during contactor disconnection, and additionally including a third system parameter, the third system parameter being at least one of: temperature during contactor disconnection, inductance, height, and contactor design. Technical advantages may include an improved estimate of contactor wear, as described for the first aspect of the disclosure.

[0029] In some examples, including at least one preferred example, preferably, the method further comprises: controlling, by the processing circuit in response to the estimated contactor wear, the order of disconnection of the contactors in a manner that takes the contactor wear into account during subsequent disconnections of the contactors and uses the contactor wear to distribute the contactor wear among the contactors. Technical advantages may include improving control strategies related to the order of disconnection of contactors, as described for the first aspect of the disclosure.

[0030] According to a fifth aspect of the present disclosure, a computer program product is provided. The computer program product comprises a program code. When the program code is executed by the processing circuit, it is used to perform the method of the fourth aspect of the present disclosure.

[0031] According to a sixth aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium comprising instructions, which, when executed by the processing circuit, cause the processing circuit to perform the method of the fourth aspect of the present disclosure.

[0032] The fifth to sixth aspects of the present disclosure can seek to solve the same problems as those described for the first to fourth aspects of the present disclosure. Therefore, the effects and features of the fifth to sixth aspects of the present disclosure are largely similar to those described above in conjunction with the first to fourth aspects of the present disclosure.

[0033] The disclosed aspects, examples (including any preferred examples), and / or the appended claims may be appropriately combined with each other, which is obvious to any person skilled in the art. Additional features and advantages are disclosed in the detailed description, claims, and drawings, and in part will be obvious to those skilled in the art or recognized by practicing the disclosure as described herein.

[0034] Also disclosed herein are computer systems, control units, code modules, computer-implemented methods, computer-readable media, and computer program products associated with the technical advantages discussed above. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1is an exemplary partially schematic side view of an electric vehicle according to one example, the electric vehicle including an energy storage system having a plurality of battery packs arranged in parallel and a control unit.

[0036] Figure 2 is a schematic diagram of a switch arrangement of an energy storage system for a vehicle according to an example, the energy storage system having a plurality of battery packs arranged in parallel and a control unit.

[0037] Figure 3 is a flow chart illustrating acts or steps of a method according to one example.

[0038] Figure 4 is a schematic diagram of a switch arrangement for an energy storage system for a vehicle according to one example.

[0039] Figure 5 is a schematic diagram of an exemplary computer system for implementing the examples disclosed herein, according to one example. DETAILED DESCRIPTION

[0040] The detailed description set forth below provides information and examples of the disclosed technology in sufficient detail to enable those skilled in the art to practice the disclosure.

[0041] The disclosed technology aims to solve the problems associated with the shortened life of a switching arrangement. The disclosed technology solves the problem by, inter alia, estimating the contactor wear due to contactor disconnection by applying a characterization model. The characterization model estimates the contactor wear for contactor disconnection with respect to a plurality of system parameters, which system parameters include at least the current and the voltage during the contactor disconnection. By controlling the sequence of contactor disconnections by using the characterization model in response to the estimated contactor wear, an improved distribution of contactor wear in contactors in a switching arrangement can be predicted in response to the estimated contactor wear, and / or contactor maintenance or contactor replacement.

[0042] Figure 1 A vehicle 1 is shown in the form of an exemplary heavy truck. The vehicle 1 is an electric vehicle, such as a fully electric vehicle or a hybrid vehicle, comprising at least one electric machine 10 (as a traction motor) powered by an energy storage system 30, wherein Figure 1 In the example of FIG. 1 , the energy storage system 30 includes three parallel battery packs 31 , 32 , 33 . The battery packs 31 , 32 , 33 are configured to provide power to at least one load (such as the motor 10 ). The vehicle 1 also includes a switch arrangement 15 , which includes an associated contactor (at Figure 2), the contactor is configured to connect and disconnect the battery packs 31, 32, 33 by closing and opening, respectively. In addition, the switch arrangement includes a control unit 17 (including a processing circuit or included therein), which is arranged and configured to control at least part of the operation of the switch arrangement 15 and / or the energy storage system 30. The vehicle 1 typically also includes other parts of the powertrain, such as a transmission, a drive shaft and wheels (not shown in detail). The motor 10 can act as an electric motor, consuming electricity provided by the battery packs 31, 32, 33, for example to provide propulsion power, and can act as a generator to generate electricity to charge the battery packs 31, 32, 33.

[0043] Figure 2 is a schematic diagram of a switch arrangement 115 and an energy storage system 130 having a plurality of parallel-connected battery packs 131 , 132 , 133 and a control unit 117 which includes or is included in a processing circuit. Figure 2 The examples shown in Figure 1 A plurality of battery packs 131, 132, 133 are arranged in parallel to be connected to a common traction voltage bus 135 and to provide a plurality of loads 110a, 110b (for example, one of the loads 110b is a motor, for example, as Figure 1 The switch arrangement 115 is configured to connect and disconnect the battery packs 131, 132, 133 from a common traction voltage bus 135. In some examples, the common traction voltage bus 135 may be included in a junction box.

[0044] Each of the battery packs 131, 132, 133 generally includes a plurality of battery cells connected in series. The battery cells may be clustered into battery modules, wherein each battery pack 131, 132, 133 includes a plurality of battery modules connected in series. The energy storage system 130 may be referred to as a multi-battery pack system.

[0045] In more detail, the energy storage system 130 includes a first battery pack 131, a second battery pack 132, and a third battery pack 133, but it should be noted that any number of battery packs equal to or greater than two may be included in the energy storage system 130. The switch arrangement 115 includes an associated contactor 141, 142, 143 for each battery pack 131, 132, 133. Thus, the switch arrangement 115 includes a first contactor 141 configured to connect and disconnect the first battery pack 131 to the common traction voltage bus 135 by closing and opening, respectively, and includes a second contactor 142 configured to connect and disconnect the second battery pack 132 to the common traction voltage bus 135 by closing and opening, respectively, and includes a third contactor 143 configured to connect and disconnect the third battery pack 133 to the common traction voltage bus 135 by closing and opening, respectively. Therefore, an associated contactor (here, a first contactor 141, a second contactor 142, and a third contactor 143) is provided for each battery pack (here, a corresponding first battery pack 131, a second battery pack 132, and a third battery pack 133). By closing the corresponding first contactor 141, the second contactor 142, and the third contactor 143 (i.e., by connecting the first battery pack 131, the second battery pack 132, and the third battery pack 133 to the common traction voltage bus 135), all or any one of the first battery pack 131, the second battery pack 132, and the third battery pack 133 can provide power to multiple loads 110a, 110b.

[0046] Any or all of the first battery pack 131, the second battery pack 132, and the third battery pack 133 can be disconnected from the common traction voltage bus 135 by disconnecting the corresponding first contactor 141, the second contactor 142, and the third contactor 143. The control unit 117 is configured to control at least part of the operation of the switch arrangement 115. The switch arrangement 115 is configured via the control unit 117 to disconnect the first battery pack 131, the second battery pack 132, and the third battery pack 133 from the common traction voltage bus 135 through the first contactor 141, the second contactor 142, and the third contactor 143, respectively. The switch arrangement 115 may include additional contactors (e.g., pre-charging contactors, auxiliary contactors) for one or more of the battery packs 131, 132, 133.

[0047] In the first state (i.e., the fully connected state), each of the first contactor 141, the second contactor 142, and the third contactor 143 is closed, and each of the first battery pack 131, the second battery pack 132, and the third battery pack 133 is connected to the common traction voltage bus 135 to provide power to the plurality of loads 110a, 110b. In the second state (i.e., the disconnected state), one, two, or all three of the first contactor 141, the second contactor 142, and the third contactor 143 are opened to disconnect the corresponding first battery pack 131, the second battery pack 132, and / or the third battery pack 133 from the common traction voltage bus 135 (as indicated by the dashed contactors in each of the first contactor 141, the second contactor 142, and the third contactor 143).

[0048] Figure 2 The energy storage system 130 includes a plurality of sensors configured to measure at least the current and voltage of each of the contactors 141, 142, 143. In more detail, the first sensor 151 is configured to measure the current and voltage of the first contactor 141, the second sensor 152 is configured to measure the current and voltage of the second contactor 142, and the third current sensor 153 is configured to measure the current and voltage of the third contactor 143. Each of the first sensor 151, the second sensor 152, and the third sensor 153 is configured to measure the current and voltage of the third contactor 143. Figure 2 Schematically shown in and can be corresponding current and voltage sensors, or composed of different sensors for measuring current and voltage. Such current sensors and voltage sensors are usually arranged to measure the current and voltage on the corresponding contactors 141, 142, 143, respectively.

[0049] When the battery packs 131, 132, 133 are disconnected and the corresponding contactors 141, 142, 143 are disconnected, the contactors 141, 142, 143 are subject to contactor wear. The level of contactor wear for a particular contactor disconnection depends on various system parameters. By implementing a characterization model that estimates contactor wear when a contactor is disconnected with respect to such system parameters, an improved estimate of contactor wear can be provided.

[0050] Figure 4 An exemplary scheme 800 for characterizing such a characterization model 801 for a contactor is shown. When applying the scheme 800 to characterize a characterization model for a contactor, for example, Figure 2The corresponding switch arrangement shown includes sensors 151, 152, and 153. The characterization of the characterization model is performed by characterization tests on how contactor wear depends on at least the current 802 and the voltage 804 on the contactor when the contactor is disconnected. In addition, other system parameters when the contactor is disconnected (such as the temperature 806 of the contactor, the system inductance 808 at the common traction voltage bus, and the height 810 of the vehicle) can be included in the scheme 800. In an exemplary characterization method, multiple characterization tests are performed on the same contactor until a failure occurs, for example, the contactor breaks or welds (the "end of life" of the contactor). Characterization tests can be performed on multiple contactors (for example, contactors of different types or contactors intended for different locations in the energy storage system). In addition, multiple contactors of the same type can be tested in parallel, with the test conditions and system parameters being the same except for one intentionally changed system parameter (e.g., all contactors run characterization tests at the same voltage, temperature, inductance, and height, but each contactor is disconnected at a different current, e.g., contactor 1 is disconnected at 10A, contactor 2 is disconnected at 30A, etc.), where the characterization test is repeated until a failure occurs. Thereafter, another set of characterization tests is performed with another system parameter on each contactor changed and repeated until a failure occurs. During the characterization test, all system parameters are recorded, e.g., the voltage across the contactor poles, the current of the contactor, and the internal temperature when the contactor is disconnected, at least during the arcing phase when the contactor is disconnected. The characterization test can be referred to as parameterization of the characterization model.

[0051] A health check of the contactor contacts and a determination of the resistance 812 between the contactor poles may also be performed to track component wear until a failure occurs. A health check may be performed by measuring the contactor resistance when the contactor is closed. Since the surface of the contact of the contactor gradually becomes irregular, the resistance increases as the contactor deteriorates (i.e., the increase in contactor wear). In addition, or as an alternative, the insulation resistance between the contactor poles when the contactor is disconnected may be used to track component wear until a failure occurs. Measuring the resistance (the contactor resistance when the contactor is closed and / or the insulation resistance when the contactor is disconnected) may provide feedback of the health state to the system. Thus, a characterization model for the contactor may be formed, including the contribution of each system parameter to contactor wear. Contactor wear may be defined, for example, by a value between 0 and 100, where 0 corresponds to no wear and 100 corresponds to a single wear that results in a contactor failure ("end of life"). Contactor wear may preferably be inferred from the contactor health state, where a value of 100 corresponds to a maximum health state, i.e., the contactor is not worn, and a value of 0 corresponds to a minimum health state, i.e., the contactor is worn and does not function (i.e., contactor failure). The characterization model can also include the conditions when the contactor fails (eg, broken or welded).

[0052] The results of the characterization test can be summarized in the characterization model by the corresponding function y=f(x) for each system parameter x. Therefore, the parameter y represents the contactor wear (or contactor wear contribution), for example, a value between 0 and 100. Therefore, the cumulative contactor wear of the contactor that has undergone multiple contactor disconnections can be recorded. Each function can be plotted as a two-dimensional graph (x, y). For different types of contactors (i.e., different contactor designs), the function y=f(x) used for the system parameter and therefore the characterization model may be different (linear, exponential, etc.). The characterization model for a specific contactor (or contactor type) can be simplified by applying a Laplace transform to each function, simplifying the Laplace transform equation to an independent function, and then inverting the Laplace transform to aggregate the various functions of different system parameters.

[0053] Back to Figure 2 , the sensors 151 , 152 , 153 can therefore provide measurement data to the control unit 117 , wherein the measurement data include system parameters of at least the current and voltage across the corresponding contactors 141 , 142 , 143 . Figure 2 In addition to the sensors 151, 152, 153 shown, the switch arrangement 115 may also include additional sensors for measuring various system parameters. For example, the additional sensors may include a temperature sensor preferably arranged in close proximity to the contactor (e.g., an NTC sensor), an LCR meter circuit configured to estimate the inductance at the contactor (e.g., the inductance of the common traction voltage bus), an on-board altimeter, and an insulation resistance monitoring circuit. Figure 4 Each of the system parameters x described (current 802, voltage 804, temperature 806, inductance 808, height 810, and resistance 812) can be measured by corresponding sensors and sensor circuits in Figure 2 The LCR meter circuit may perform an inductance check and record the measured inductance during initialization of the energy storage system 130 and prior connection of the battery packs 131, 132, 133 to the common traction voltage bus 135 (i.e., the contactors 141, 142, 143). When the battery packs 131, 132, 133 are subsequently connected to the common traction voltage bus 135 (i.e., the contactors 141, 142, 143 are closed) and the contactors 141, 142, 143 are subsequently opened (typically at each opening), the control unit 117 records the current and voltage of each open contactor through sensors 151, 152, 153 and typically at least during arc formation, and optionally the temperature of the corresponding contactor. Using this measurement data and potentially in combination with the vehicle's height data and the measured inductance, a characterization model may be used to determine contactor wear or contactor wear contribution. Thus, the health state of the contactors may be taken into account and reduced in an accurate manner.

[0054] More generally, the control unit 117 is configured to provide a characterization model for each of the contactors 141, 142, 143. As previously described, the characterization model defines contactor wear for contactor disconnection with respect to a plurality of system parameters, which system parameters include at least current and voltage during contactor disconnection. In addition, the control unit 117 is configured to determine system parameters during operation of the switch arrangement 115. For example, the sensors 151, 152, 153 measure at least contactor current and contactor voltage during contactor disconnection. Therefore, the control unit 117 is configured to estimate contactor wear for each of the contactors 141, 142, 143 by applying the determined system parameters to the corresponding characterization model. Therefore, the control unit 117 can control the order of disconnection of the contactors 141, 142, 143 in response to the estimated contactor wear, and / or predict the maintenance of the contactors 141, 142, 143 or the replacement of the contactors in response to the estimated contactor wear.

[0055] In more detail, the switch arrangement 115 is configured via the control unit 117 to disconnect the first battery pack 131, the second battery pack 132 and the third battery pack 133 from the common traction voltage bus 135 through the first contactor 141, the second contactor 142 and the third contactor 143, respectively, so that the first battery pack 131, the second battery pack 132 and the third battery pack 133 are disconnected in the order of disconnecting one contactor first (e.g., the first contactor 141), disconnecting one contactor thereafter (e.g., the second contactor 142) and disconnecting one contactor last (e.g., the third contactor 143), so that all battery packs 131, 132, 133 are disconnected (i.e., so that no battery pack is connected to the common traction voltage bus 135). For each contactor disconnection, the control unit 117 can apply a characterization model using system parameters to calculate and estimate contactor wear. Therefore, the accumulated contactor wear of each of the contactors 141, 142, 143 can be determined and recorded.

[0056] For example, in a first state (i.e., a fully connected state), each of the first contactor 141, the second contactor 142, and the third contactor 143 is closed, and each of the first battery pack 131, the second battery pack 132, and the third battery pack 133 is connected to the common traction voltage bus 135, and is therefore able to provide power to any of the loads 110a, 110b. In a second state (i.e., a disconnected state), each of the first contactor 141, the second contactor 142, and the third contactor 143 is disconnected in a manner that each of the first battery pack 131, the second battery pack 132, and the third battery pack 133 is disconnected from the common traction voltage bus 135, thereby terminating the power supply to the loads 110a, 110b (e.g., in response to a shutdown signal of the loads 110a, 110b). During disconnection, two of the battery packs (e.g., the first battery pack 131 and the second battery pack 132 in the above example) are disconnected (by disconnecting the first contactor 141 and the second contactor 142) before the third battery pack 131. When the first contactor 141 and the second contactor 142 are disconnected, a relatively small arc will occur in the air gap of the first contactor 141 and the second contactor 142 because the third battery pack 133 remains connected to the common traction voltage bus 135 and an alternative path for current is available. Therefore, the first contactor 141 and the second contactor 142 will suffer relatively small contactor wear, which is determined by implementing the characterization model by the control unit 117. During the disconnection of the third battery pack 133, the third contactor 143 is disconnected (i.e., the last contactor of the three contactors 141, 142, 143 is disconnected), which means that after disconnecting the third contactor 143, no battery pack is connected to the common traction voltage bus 135. As a result, a relatively large arc will be formed in the air gap of the third contactor 143, which is particularly prominent when all battery packs 131, 132, 133 of the energy storage system 130 are disconnected and the inductive circuit involving the loads 110a, 110b will be interrupted or disconnected. The formation of such an arc causes relatively large contactor wear of the third contactor 143, which is determined by implementing the characterization model by the control unit 117. The disconnection of the third contactor 143 leads to a third state (i.e., a disconnected state) of the energy storage system 130, each of the first contactor 141, the second contactor 142, and the third contactor 143 is disconnected, and each of the first battery pack 131, the second battery pack 132, and the third battery pack 133 is disconnected from the common traction voltage bus 135. Therefore, the loads 110a, 110b cannot be powered by the energy storage system 130.Therefore, in order to summarize the first state to the third state, the control unit 117 can be configured to identify multiple parallel-arranged battery packs 131, 132, 133 connected to the common traction voltage bus 135 of the energy storage system 130, and identify the associated contactors 141, 142, 143 of the multiple parallel-arranged battery packs 131, 132, 133, wherein the order of controlling the contactors 141, 142, 143 to be disconnected is performed for all multiple parallel-arranged battery packs 131, 132, 133 until no battery packs 131, 132, 133 are connected to the common traction voltage bus.

[0057] Assuming that the contactor wear is equal before such disconnection of the battery packs 131, 132, 133, the accumulated contactor wear of the third contactor 143 will be higher than that of the first contactor 141 and the second contactor 142. In other words, the third contactor 143 is more likely to suffer from a contactor failure than the first contactor 141 and the second contactor 142. Therefore, when the battery packs 131, 132, 133 are subsequently disconnected (obviously, after the previous connection of the battery packs 131, 132, 133 was made by closing the contactors 141, 142, 143), the control unit 117 controls the order in which the contactors 141, 142, 143 are disconnected, so that one of the first contactor 141 and the second contactor 142 is disconnected last instead. In other words, during the subsequent repetition of the first state, the second state and the third state, the higher accumulated contactor wear of the third contactor 143 as described above is taken into account. Therefore, the control unit 117 can be configured to control the order in which the contactors 141, 142, 143 are disconnected in response to the estimated contactor wear in a manner that takes into account the contactor wear during subsequent disconnections of the contactors 141, 142, 143 and uses the contactor wear to distribute the contactor wear among the contactors 141, 142, 143. Therefore, the contactor wear is better distributed among the contactors 141, 142, 143 in the switch arrangement 115. Therefore, contactor failures due to excessive contactor wear of a single contactor can be avoided or at least reduced. For example, the order in which the battery packs 131, 132, 133 are disconnected can be controlled so that the battery packs other than the battery packs with the contactors with the highest cumulative contactor wear are disconnected last.

[0058] As a supplement or alternative to controlling the order in which the contactors 141, 142, 143 are disconnected in response to estimated contactor wear as described above, the control unit 117 may predict maintenance or contactor replacement of the contactors 141, 142, 143 in response to estimated contactor wear. For example, if the cumulative contactor wear of a contactor reaches a predetermined threshold, for example, 20% of the contactor health state, the control unit 117 may indicate (for example, to the vehicle driver) that such contactor requires maintenance or replacement. Thus, contactor failures due to excessive contactor wear of a single contactor may be avoided or at least reduced. If a contactor is replaced and the old contactor is replaced with a new contactor that has no accumulated contactor wear, such contactor will be disconnected last more often due to the distribution of contactor wear among the contactors (at least at the beginning of their operation).

[0059] The control unit 117 is generally configured to track contactor wear or accumulated contactor wear of each of the first contactor 141, the second contactor 142, and the third contactor 143. Figure 2 As shown in , the switch arrangement 115 further comprises a memory 118, which is included in the control unit 117. Such a memory 118 can be used to track contactor wear or accumulated contactor wear. Furthermore, the memory 118 can be used to store a characterization model.

[0060] The switch arrangement 115 can be further configured via the control unit 117 to connect the battery packs 131, 132 and 133 to the common traction voltage bus 135 by closing the contactors 141, 142, 143, and to alternately connect and disconnect the battery packs 131, 132 and 133 from the common traction voltage bus 135, wherein the sequence of controlling the contactors 141, 142, 143 to be opened as described above is performed for each disconnection. The sequence can, for example, include alternating the last battery pack to be disconnected among the first battery pack 131, the second battery pack 132 and the third battery pack 133, and thus the last contactor to be opened among the first contactor 141, the second contactor 142 and the third contactor 143.

[0061] It should be mentioned that Figure 2The switch arrangement 115 may also include a first pre-charging contactor arranged in parallel with the first contactor 141, wherein the first pre-charging contactor is arranged in series with the first pre-charging resistor, and includes a second pre-charging contactor arranged in parallel with the second contactor 142, wherein the second pre-charging contactor is arranged in series with the second pre-charging resistor, and includes a third pre-charging contactor arranged in parallel with the third contactor 143, wherein the third pre-charging contactor is arranged in series with the third pre-charging resistor. In addition, the first battery pack 131 can be connected in series with a first auxiliary contactor, which is arranged on a side of the first battery pack 131 opposite to the first contactor 141 (for example, the first contactor 141 is arranged at the positive side of the first battery pack 131, and the first auxiliary contactor is arranged at the negative side of the first battery pack 131). Accordingly, the second battery pack 132 can be connected in series with the second auxiliary contactor, which is arranged on the side of the second battery pack 132 opposite to the second contactor 142, and the third battery pack 133 can be connected in series with the third auxiliary contactor, which is arranged on the side of the third battery pack 133 opposite to the second contactor 143.

[0062] Figure 3 is a switch arrangement for controlling an energy storage system of a vehicle (such as Figure 2 Flow chart of a computer implemented method of a switch arrangement 115 and an energy storage system 130).

[0063] In a first action or step S10, a processing circuit of a computer system provides a characterization model for each of a plurality of contactors of a switch arrangement. Each contactor of the switch arrangement is configured to connect and disconnect an associated battery pack of an energy storage system of a vehicle by closing and opening, respectively. The characterization model defines contactor wear for contactor opening with respect to a plurality of system parameters, including at least current and voltage during contactor opening. The characterization model may, for example, be a reference Figure 4 Thus, the characterization model may define the contactor wear as a function of the plurality of system parameters, the system parameters comprising at least the current and voltage during contactor disconnection, and additionally comprising a third system parameter, the third system parameter being at least one of: temperature during contactor disconnection, inductance, height, and contactor design. For example and with reference to Figure 1 The processing circuit may include or be included in the control unit 17 of the vehicle 1, or refer to Figure 2 The processing circuit may include or be included in the control unit 117 of the switch arrangement 115 .

[0064] In a second optional action or step S20, the processing circuit receives measurement data from a plurality of sensors of the energy storage system, wherein the measurement data includes system parameters.

[0065] In a third action or step S30, the processing circuit determines a system parameter during operation of the switching arrangement.

[0066] In a fourth action or step S40 , for each of the contactors, the processing circuit estimates contactor wear by applying the determined system parameters to the corresponding characterization model.

[0067] In a fifth action or step S50, the processing circuit controls the order in which the contactors are opened in response to the estimated contactor wear. That is, when the associated contactor is opened, the battery pack is disconnected.

[0068] Alternatively or additionally, in a sixth action or step S60, the processing circuit predicts contactor maintenance or contactor replacement in response to the estimated contactor wear. For example, the contactor maintenance information may be sent to a display, such as a vehicle monitor, for example. Thus, the driver of the vehicle may utilize the contactor maintenance information and decide to perform maintenance on the switch arrangement. That is, the fifth action or step S50 and the sixth action or step S60 may be parallel actions or steps, such as Figure 3 As shown, or they may be sequential actions or steps, wherein action or step S50 is performed before action or step S60, or action or step S60 is performed before action or step S50.

[0069] In a first optional pre-action or pre-step S5 of the first action or step S10, the processing circuit identifies a plurality of parallel arranged battery packs connected to a common traction voltage bus of the energy storage system. In a second optional pre-action or step S7 of the first action or step S10, the processing circuit identifies contactors associated with the plurality of parallel arranged battery packs. Thus, a fifth action or step S50 of controlling the order of opening of the contactors may be performed for all of the plurality of parallel arranged battery packs until no battery packs are connected to the common traction voltage bus.

[0070] As previously described, the method may include a seventh action or step S70: the processing circuit closes the contactor to connect the battery pack to the common traction voltage bus. In addition, as previously described, the battery pack can be alternately connected and disconnected from the common traction voltage bus, wherein the action or step of disconnecting includes controlling the order in which the contactors are disconnected. In other words, the fifth action or step S50 may include repeatedly performing the third action or step S30 and the fourth action or step S40, potentially also performing the optional second action or step S20. Therefore, the battery pack disconnection sequence controlled by the switch arrangement can be applied over time and during operation of the energy storage system. For example, the battery pack disconnection sequence controlled by the switch arrangement may include rotating the battery pack that is disconnected last.

[0071] It should be noted that not all battery packs of the energy storage system need to be connected every time the energy storage system is to power a load connected to the common traction voltage bus. For example, if the load requires only two of the three battery packs to be powered, the third battery pack and therefore the contactors associated with the third battery pack can be idle in such cases. During disconnection of the connected battery packs, the disconnection sequence controlled by the switch arrangement will be applied to the battery packs connected to the common traction voltage bus for powering the loads, i.e., in this case, the first battery pack and the second battery pack.

[0072] In an optional sub-action or sub-step S55 of the fifth action or step S50, the processing circuit determines the accumulated contactor wear of each of the contactors by applying the characterization model of each of the contactors during each contactor disconnection. The fifth action or step S50 can be performed by controlling the order of contactor disconnections in response to the estimated contactor wear in a manner that considers the contactor wear during subsequent disconnections of the contactors and uses the contactor wear to distribute the contactor wear among the contactors. In other words, the accumulated contactor wear of each contactor can be recorded.

[0073] Figure 1 The control unit 17 or Figure 2 The control unit 117 may be configured to perform as described in reference Figure 3 Therefore, as described in reference Figure 3 The described method may be implemented in a computer program product comprising a computer program product for executing a reference when executed by a processing circuit. Figure 3 Alternatively, as referenced Figure 3 The described method may be implemented in a non-transitory computer-readable storage medium comprising instructions which, when executed by a processing circuit, cause the processing circuit to perform the Figure 3 Therefore, the control unit 17 may include a method for causing the energy storage system 30 to be operated according to the reference Figure 3 Instructions describing at least some actions or steps to operate. In addition, Figure 2 The control unit 117 may include a device for causing the switch arrangement 115 to be configured according to a reference Figure 3 Instructions that describe at least some actions or steps to operate. Figure 1 The control unit 17 of the vehicle 1 and Figure 2 The control unit 117 of the switch arrangement 115 may constitute or be included in a control system comprising a control system configured to perform as described in reference Figure 3 One or more control units of the method described. Now referring to Figure 5 Such a control system 1000 is described.

[0074] Figure 5 is used to implement the examples disclosed herein (e.g., as referenced Figure 3 Schematic diagram of a computer system 1000 for executing instructions from a computer-readable medium to perform these and / or any functions or processes described herein. The computer system 1000 may be connected (e.g., networked) to other machines in a LAN, an intranet, an extranet, or the Internet. Although only a single device is shown, the computer system 1000 may include any collection of devices that execute an instruction set (or multiple instruction sets) individually or jointly to perform any one or more of the methods discussed herein. Therefore, any reference to a computer system, a computing system, a computer device, a computing device, a control system, a control unit, an electronic control unit (ECU), a processor device, a processing circuit, etc. in the present disclosure and / or claims includes a reference to one or more such devices to execute an instruction set (or multiple instruction sets) individually or jointly to perform any one or more of the methods discussed herein. For example, the control system may include a single control unit or multiple control units connected to each other or otherwise communicatively coupled, so that any executed functions may be distributed between the control units as needed. In addition, such devices may communicate with each other or other devices through various system architectures (such as directly or via a controller area network (CAN) bus, etc.).

[0075] The computer system 1000 may include at least one computing device or electronic device that can include firmware, hardware and / or execute software instructions to implement the functionality described herein. The computer system 1000 may include a processing circuit 1002 (e.g., a processing circuit including one or more processor devices or control units), a memory 1004, and a system bus 1006. The computer system 1000 may include at least one computing device having a processing circuit 1002. The system bus 1006 provides an interface for system components including, but not limited to, the memory 1004 and the processing circuit 1002. The processing circuit 1002 may include any number of hardware components for performing data or signal processing or for executing computer code stored in the memory 1004. The processing circuit 1002 may include, for example, a general purpose processor, a special purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a circuit containing a processing component, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processing circuit 1002 may also include computer executable code that controls the operation of the programmable device.

[0076] The system bus 1006 can be any of several types of bus structures, which can be further interconnected to a memory bus (with or without a memory controller), a peripheral bus, and / or a local bus using any of a variety of bus architectures. The memory 1004 can be one or more devices for storing data and / or computer code to complete or facilitate the methods described herein. The memory 1004 may include a database component, an object code component, a script component, or any type of information structure for supporting various activities herein. Any distributed or local memory device can be utilized with the systems and methods of the present specification. The memory 1004 can be communicatively connected to the processing circuit 1002 (e.g., via a circuit or any other wired, wireless, or network connection) and can include computer code for performing one or more processes described herein. The memory 1004 may include nonvolatile memory 1008 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.) and volatile memory 1010 (e.g., random access memory (RAM)), or any other medium that can be used to carry or store desired program code in the form of machine-executable instructions or data structures and that can be accessed by a computer or other machine having the processing circuit 1002. A basic input / output system (BIOS) 1012 may be stored in the nonvolatile memory 1008 and may include the basic routines that help to transfer information between elements within the computer system 1000.

[0077] The computer system 1000 may also include or be coupled to non-transitory computer-readable storage media such as storage device 1014, which may include, for example, an internal or external hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), a HDD for storage (e.g., EIDE or SATA), flash memory, etc. The storage device 1014 and other drives associated with computer-readable and computer-usable media may provide non-volatile storage of data, data structures, computer-executable instructions, etc.

[0078] The hard-coded or soft-coded computer code may be provided in the form of one or more modules. The module may be implemented as software and / or hard-coded in the circuit to implement the functions described herein in whole or in part. These modules may be stored in the storage device 1014 and / or the volatile memory 1010, which may include an operating system 1016 and / or one or more program modules 1018. All or part of the examples disclosed herein may be implemented as a computer program 1020 stored on a temporary or non-temporary computer-usable or computer-readable storage medium (e.g., a single medium or multiple media) such as the storage device 1014, which includes complex programming instructions (e.g., complex computer-readable program code) that cause the processing circuit 1002 to perform the actions described herein. Therefore, the computer-readable program code of the computer program 1020 may include software instructions for implementing the functions of the examples described herein when executed by the processing circuit 1002. In some examples, storage device 1014 may be a computer program product (e.g., a readable storage medium) having computer program 1020 stored thereon, wherein at least a portion of computer program 1020 may be loadable (e.g., loaded into a processor) for implementing the functionality of the examples described herein when executed by processing circuit 1002. Processing circuit 1002 may serve as a controller or control system of computer system 1000 for implementing the functionality described herein.

[0079] The computer system 1000 may include an input device interface 1022 configured to receive input and selections to be transmitted to the computer system 1000 when executing instructions, such as from a keyboard, mouse, touch-sensitive surface, etc. Such input devices can be connected to the processing circuit 1002 through an input device interface 1022 coupled to the system bus 1006, but can be connected through other interfaces (such as a parallel port, an Institute of Electrical and Electronics Engineers (IEEE) 1394 serial port, a universal serial bus (USB) port, an IR interface, etc.). The computer system 1000 may include an output device interface 1024, which is configured to forward output to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system 1000 may include a communication interface 1026 suitable for communicating with a network as appropriate or as needed.

[0080] The actions described in any of the exemplary aspects of this article are described to provide examples and discussions. These actions can be performed by hardware components, can be embodied in machine executable instructions so that a processor performs these actions, or can be performed by a combination of hardware and software. Although a specific order of method actions can be shown or described, the order of these actions may be different. In addition, two or more actions may be performed simultaneously or partially simultaneously.

[0081] Example 1. A computer system comprising a processing circuit configured to: - providing a characterization model for each of a plurality of contactors of a switch arrangement, each contactor being configured to connect and disconnect an associated battery pack of an energy storage system of a vehicle by closing and opening, respectively, the characterization model defining contactor wear for contactor opening with respect to a plurality of system parameters, the system parameters comprising at least current and voltage during contactor opening, - determining said system parameters during operation of said switching arrangement, - estimating the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; - controlling a sequence of opening of the contactors in response to the estimated contactor wear, and / or predicting contactor maintenance or contactor replacement in response to the estimated contactor wear.

[0082] Example 2. The computer system of Example 1, wherein the processing circuit is further configured to: receive measurement data from a plurality of sensors of the energy storage system, wherein the measurement data includes the system parameters.

[0083] Example 3. A computer system as described in any of Examples 1 to 2, wherein the processing circuit is further configured to: identify multiple parallel-arranged battery packs connected to a common traction voltage bus of the energy storage system, and identify the associated contactors of the multiple parallel-arranged battery packs, wherein the order of controlling the contactors to open is performed for all of the multiple parallel-arranged battery packs until no battery packs are connected to the common traction voltage bus.

[0084] Example 4. A computer system as described in Example 3, wherein the processing circuit is further configured to: after controlling the sequence of opening the contactors, connect the battery pack to the common traction voltage bus by closing the contactors, and thereafter: alternately connect and disconnect the battery pack from the common traction voltage bus, wherein the sequence of controlling the opening of the contactors is performed for each disconnection.

[0085] Example 5. A computer system as described in any of Examples 1 to 4, wherein the processing circuit is further configured to: determine the accumulated contactor wear of each of the contactors by applying the characterization model to each of the contactors during each contactor disconnection.

[0086] Example 6. The computer system of any of Examples 1 to 5, wherein the system parameters further include at least one of: temperature during contactor opening, inductance, height, and contactor design.

[0087] Example 7. A computer system as described in any of Examples 1 to 6, wherein the characterization model defines the contactor wear as a function of the multiple system parameters, the system parameters including at least current and voltage during contactor disconnection, and further including a third system parameter, the third system parameter being at least one of: temperature, inductance, height, and contactor design during contactor disconnection.

[0088] Example 8. The computer system of any one of Examples 1 to 7, wherein the characterization model is defined by the following formula: CW = A*I+B*V+C*X Where CW is the wear of the contactor, I is the current on the contactor, V is the voltage on the contactor, X is a third system parameter when the contactor is open, such as temperature, and A, B and C are constants.

[0089] Example 9. A computer system as described in any of Examples 1 to 8, wherein the processing circuit is further configured to: in response to the estimated contactor wear, control the order of the contactor disconnections in a manner that takes the contactor wear into account during subsequent disconnections of the contactors and distributes the contactor wear among the contactors using the contactor wear.

[0090] Example 10. A computer system as described in any of Examples 1 to 9, wherein the processing circuit is further configured to: control the order of disconnection of the contactors in response to the estimated contactor wear in a manner such that a contactor other than a contactor with the highest contactor wear is disconnected as the last contactor.

[0091] Example 11. A switch arrangement for an energy storage system for a vehicle, the energy storage system comprising a plurality of battery packs arranged in parallel, the switch arrangement comprising: - an associated contactor for each battery pack, the contactor being configured to connect and disconnect the battery packs by closing and opening, respectively, - a control unit, the control unit being configured to: - providing a characterization model for each of the contactors, the characterization model defining contactor wear for contactor opening with respect to a plurality of system parameters, the system parameters comprising at least current and voltage during contactor opening, - determining said system parameters during operation of said switching arrangement, - estimating the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; - controlling a sequence of opening of the contactors in response to the estimated contactor wear, and / or predicting contactor maintenance or contactor replacement in response to the estimated contactor wear.

[0092] Example 12. A vehicle comprising a computer system as described in any one of Examples 1 to 10 or a switch arrangement as described in Example 11.

[0093] Example 13. A computer-implemented method comprising: - providing, by processing circuitry of the computer system, a characterization model for each of a plurality of contactors of the switch arrangement, each contactor being configured to connect and disconnect, by closing and opening, respectively, an associated battery pack of an energy storage system of the vehicle, the characterization model defining contactor wear for contactor opening with respect to a plurality of system parameters, the system parameters including at least current and voltage during contactor opening, - determining, by said processing circuit, said system parameter during operation of said switching arrangement, - estimating, by the processing circuitry, the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; - controlling, by the processing circuit, a sequence of opening of the contactors in response to the estimated contactor wear, and / or predicting, by the processing circuit, contactor maintenance or contactor replacement in response to the estimated contactor wear.

[0094] Example 14. The method of Example 13, further comprising: - receiving, by the processing circuit, measurement data from a plurality of sensors of the energy storage system, wherein the measurement data comprises the system parameters.

[0095] Example 15. A method as described in any one of Examples 13 to 14, further comprising: - identifying by the processing circuit a plurality of parallel-arranged battery packs connected to a common traction voltage bus of the energy storage system, and identifying by the processing circuit the associated contactors of the plurality of parallel-arranged battery packs, wherein the order of controlling the contactors to be disconnected is performed for all of the plurality of parallel-arranged battery packs until no battery pack is connected to the common traction voltage bus.

[0096] Example 16. The method of any one of Examples 13 to 15, further comprising: - determining, by the processing circuit, accumulated contactor wear of each of the contactors by applying the characterization model to each of the contactors during each contactor opening.

[0097] Example 17. A method as described in any of Examples 13 to 16, wherein the characterization model defines the contactor wear as a function of the multiple system parameters, the system parameters including at least current and voltage during contactor disconnection, and further including a third system parameter, the third system parameter being at least one of: temperature, inductance, height, and contactor design during contactor disconnection.

[0098] Example 18. A method as described in any one of Examples 13 to 17, further comprising: - controlling, by the processing circuit in response to the estimated contactor wear, the order of disconnection of the contactors in a manner that takes into account the contactor wear during subsequent disconnections of the contactors and distributes the contactor wear among the contactors using the contactor wear.

[0099] Example 19. A computer program product comprising program code for performing the method of any one of Examples 12 to 18 when executed by the processing circuit.

[0100] Example 20. A non-transitory computer-readable storage medium comprising instructions that, when executed by the processing circuit, cause the processing circuit to perform the method of any of Examples 12 to 18.

[0101] The terms used herein are only for the purpose of describing specific aspects and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an" and "said" are intended to include plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It should also be understood that the terms "include" and / or "comprising" when used herein indicate the presence of stated features, integers, actions, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components and / or their groups.

[0102] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0103] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element to another element as shown in the figures. It should be understood that these terms and the terms discussed above are intended to cover different orientations of the device in addition to the orientation depicted in the figures. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, the element may be directly connected or coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0104] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It should also be understood that, unless otherwise clearly defined herein, the terms used herein should be interpreted as meanings consistent with their meanings in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0105] It should be understood that the present disclosure is not limited to the aspects described above and shown in the accompanying drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and the appended claims. In the drawings and description, various aspects have been disclosed for illustrative purposes only and not for limiting purposes, and the scope of the present disclosure is set forth in the appended claims.

Claims

1. A computer system comprising a processing circuit, wherein the processing circuit is configured to: - providing a characterization model for each of a plurality of contactors of a switch arrangement, each contactor being configured to connect and disconnect an associated battery pack of an energy storage system of a vehicle by closing and opening, respectively, the characterization model defining contactor wear for contactor opening with respect to a plurality of system parameters, the system parameters comprising at least current and voltage during contactor opening, - determining said system parameters during operation of said switching arrangement, - estimating the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; - controlling a sequence of opening of the contactors in response to the estimated contactor wear, and / or predicting contactor maintenance or contactor replacement in response to the estimated contactor wear.

2. The computer system of claim 1, wherein the processing circuit is further configured to: receive measurement data from a plurality of sensors of the energy storage system, wherein the measurement data includes the system parameters.

3. A computer system as described in any one of claims 1 to 2, wherein the processing circuit is further configured to: identify multiple parallel-arranged battery packs connected to a common traction voltage bus of the energy storage system, and identify the associated contactors of the multiple parallel-arranged battery packs, wherein the order of controlling the contactor disconnection is performed for all of the multiple parallel-arranged battery packs until no battery pack is connected to the common traction voltage bus.

4. The computer system of claim 3, wherein the processing circuit is further configured to: after controlling the sequence of opening of the contactors, connect the battery pack to the common traction voltage bus by closing the contactors, and thereafter: The battery pack is alternately connected and disconnected from the common traction voltage bus, wherein the sequence of controlling the contactors to open is performed for each disconnection.

5. The computer system of any one of claims 1 to 4, wherein the processing circuit is further configured to determine accumulated contactor wear of each of the contactors by applying the characterization model to each of the contactors during each contactor opening.

6. A computer system as described in any one of claims 1 to 5, wherein the characterization model defines the contactor wear as a function of the multiple system parameters, the system parameters including at least the current and voltage during contactor disconnection, and additionally including a third system parameter, the third system parameter being at least one of the following: temperature during contactor disconnection, inductance, height, and contactor design.

7. A computer system as described in any one of claims 1 to 6, wherein the processing circuit is further configured to: in response to the estimated contactor wear, control the order of disconnection of the contactors in a manner that takes into account the contactor wear during subsequent disconnections of the contactors and uses the contactor wear to distribute the contactor wear among the contactors.

8. A computer system as described in any one of claims 1 to 7, wherein the processing circuit is further configured to: control the order of disconnection of the contactors in a manner such that a contactor other than a contactor with the highest contactor wear is disconnected as the last contactor in response to the estimated contactor wear.

9. A switch arrangement (15, 115) for an energy storage system (30, 130) for a vehicle (1), the energy storage system comprising a plurality of battery packs (31, 32, 33, 131, 132, 133) arranged in parallel, the switch arrangement include: - an associated contactor (141, 142, 143) for each battery pack, the contactor being configured to connect and disconnect the battery packs by closing and opening, respectively, - a control unit (117), the control unit being configured to: - providing a characterization model for each of the contactors, the characterization model defining contactor wear for contactor opening with respect to a plurality of system parameters, the system parameters comprising at least current and voltage during contactor opening, - determining said system parameters during operation of said switching arrangement, - estimating the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; - controlling a sequence of opening of the contactors in response to the estimated contactor wear, and / or predicting contactor maintenance or contactor replacement in response to the estimated contactor wear.

10. A vehicle comprising a computer system as claimed in any one of claims 1 to 8 or a switch arrangement as claimed in claim 9.

11. A computer-implemented method, wherein include: - providing (S10) by a processing circuit of the computer system a characterization model for each of a plurality of contactors of the switch arrangement, each contactor being configured to connect and disconnect an associated battery pack of an energy storage system of the vehicle by closing and opening, respectively, the characterization model defining contactor wear for contactor opening with respect to a plurality of system parameters, the system parameters comprising at least current and voltage during contactor opening, - determining (S30) by the processing circuit the system parameter during operation of the switching arrangement, - estimating ( S40 ), by the processing circuit, the contactor wear for each of the contactors by applying the determined system parameters to the corresponding characterization model; - controlling (S50) by the processing circuit a sequence of contactor openings in response to the estimated contactor wear, and / or predicting (S60) by the processing circuit a contactor maintenance or contactor replacement in response to the estimated contactor wear.

12. The method of claim 11, wherein the characterization model defines the contactor wear as a function of the plurality of system parameters, the system parameters comprising at least current and voltage during contactor disconnection, and additionally comprising a third system parameter, the third system parameter being at least one of: temperature during contactor disconnection, inductance, height, and contactor design.

13. The method according to any one of claims 11 to 12, further comprising: include: - controlling (S50a) the sequence of opening of the contactors by the processing circuit in response to the estimated contactor wear in a manner that takes the contactor wear into account during subsequent openings of the contactors and distributes the contactor wear among the contactors using the contactor wear.

14. A computer program product comprising program code for performing the method of any one of claims 11 to 13 when executed by the processing circuit.

15. A non-transitory computer-readable storage medium comprising instructions which, when executed by the processing circuit, cause the processing circuit to perform the method of any one of claims 11 to 13.

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