Protection assembly, battery, photovoltaic unit, means of transport and production line

Abstract

Schützbaugruppe (15) comprising: • a first contactor (HS1) with a first blow magnet (9a), • a second contactor (HS2) with a second blow magnet (9b), and • one evaluation unit (6), wherein the first contactor (HS1) and the second contactor (HS2) each have a preferred current direction (14a, 14b) in which their respective blow-out magnet (9a, 9b) is able to extinguish an arc better than in a reverse current direction; wherein the first contactor (HS1) and the second contactor (HS2) are connected to each other in such a way that a first current flows through the first contactor (HS1) in the preferred current direction (14a) and through the second contactor (HS2) in the reverse current direction (14b), and the evaluation unit (6) is set up, • to interrupt the first current, open the first contactor (HS1) and then open the second contactor (HS2) and / or • to interrupt a second current, open the second contactor (HS2) and then open the first contactor (HS1).

Description

[0001] The invention relates to a protection assembly, a battery, a photovoltaic unit, a means of transport and a production line.

[0002] Many high-voltage circuits incorporate electromechanical contactors. A contactor is a switch used to interrupt an electrical circuit. In the case of traction batteries for road vehicles, these contain a switching unit with two electromechanical contactor units, each capable of electrically connecting or disconnecting the positive and negative paths, respectively. If the current-carrying capacity of a contactor is exceeded in a high-voltage battery, it opens. This is particularly important in traction batteries to protect the high-voltage components and prevent damage. When the contactors open due to current flow under load, arcs form between the contactor contacts. With increasing use and a growing number of switching operations, the contactors are at risk of wearing out or even welding together. In the event of such welding, for example,Due to an electric arc, orderly opening is no longer possible despite the withdrawal of a control signal, which poses a potential danger.

[0003] To minimize this potential hazard, contactors are equipped with a so-called arc-extinguishing magnet. This magnet uses the Lorentz force to lengthen the arcs within the contactor, thus extinguishing them more quickly. During this arc extinguishing process, the magnets divert the resulting arc against a housing wall of the contactor. The contactors have a preferred direction of current flow in which arc extinguishing functions in this way. With a reversed current flow direction, the arc would be deflected towards the center of the contactor housing, i.e., between the contactor contacts, and the targeted arc lengthening would not occur. This would result in an increased risk of damage to the contactors. Therefore, the main contactors of the battery junction box for traction batteries in road vehicles are installed in such a way that the preferred direction of the contactors corresponds to that of the initial current, e.g.,of the discharge current. However, currents cannot be switched in the direction of flow independently of their amplitude while minimizing damage to the contactor contacts.

[0004] DE 10 2012 018 321 A1 relates to a method for disconnecting a battery system under load, wherein the battery system comprises an arrangement of a first contactor connected to a first terminal (e.g., negative terminal) of a battery cell, a second contactor connected to a second terminal of a battery cell (e.g., positive terminal), and a pre-charging relay. Before the first contactor opens, the pre-charging relay, which is connected in series with it and equipped with a pre-charging resistor, is closed. Then, first the first contactor and then the second contactor and / or the pre-charging relay are opened.

[0005] DE 10 2012 021 397 A1 discloses a single, small-dimension electromagnetic contactor which, due to its symmetry properties, ensures arc quenching regardless of the direction of the current through the contact point. The objective is therefore to provide a contactor assembly that reduces damage to the contactor contacts regardless of the current direction or amplitude.

[0006] The aforementioned problem is solved according to the invention by the subject matter of claim 1. According to a first aspect, the present invention relates to a contactor assembly. The contactor assembly comprises a first contactor with a first blow-out magnet and a second contactor with a second blow-out magnet and an evaluation unit, e.g., a CPU and / or a microcontroller. Here, the first and the second contactors each have a preferred current direction in which their respective blow-out magnet is able to extinguish an arc, as already explained above, better than in a reverse current direction. Here, the first contactor and the second contactor are connected to each other such that a first current, e.g., a discharge current, particularly during the operation of a means of transport, flows through the first contactor in the preferred current direction and through the second contactor in the reverse current direction. This has the effect that a second current, e.g.,A charging current flows through the second contactor in the preferred current direction and the first contactor in the opposite direction. This can be implemented, for example, within a traction battery of a vehicle. Here, the first and second contactors, together with the evaluation unit, can form a so-called "battery junction box." Furthermore, the evaluation unit is configured to interrupt the first current, e.g., the discharge current, by opening the first contactor and then the second contactor, and / or to interrupt a second current, e.g., a charging current, by opening the second contactor and then the first contactor. In other words, the evaluation unit opens the contactor through which the current flows in its preferred direction first, in order to achieve optimal arc quenching by the blow-out magnet.The second contactor, which is arranged in the opposite direction and would not achieve optimal arc extinguishing as discussed above, is opened later to prevent damage (or welding due to arcing) to the contactor contacts. This minimizes damage to the contactor contacts, thereby reducing the aforementioned risks and minimizing costs, such as those associated with replacing a contactor.

[0007] Any contactor suitable for use in a high-voltage circuit, preferably a DC circuit, can be used as the contactor of the present invention. This could include, for example, all DC contactors. Communication between the contactor and the evaluation unit, i.e., the control signal, can be transmitted via a bus system, e.g., a CAN bus system, and / or via a power line, and / or wirelessly (e.g., via Bluetooth, infrared, and / or radio waves), and / or via other communication methods known from the prior art.

[0008] Suitable blow-out magnets include permanent magnets and / or electromagnets, provided they are configured to lengthen the arc using the appropriate Lorentz force. The blow-out magnet thus generates a magnetic field in the area of ​​the separable contacts.

[0009] The sub-claims include beneficial further training opportunities.

[0010] In an advantageous further development, the evaluation unit is configured to open the first contactor to interrupt the initial current, e.g., a discharge current, and only after a predefined time period and / or after the initial current, e.g., the discharge current, which is preferably necessary to create an arc, has decayed to a predefined value, does it open the second contactor. The longer the predefined time period, the lower the arc energy and thus the risk of arc formation or welding of the contactor contacts. For example, the predefined time period can be set such that only 1 / 10 of the original current is present when the second contactor is opened. The evaluation unit can, for example, access a storage unit, e.g., a magnetic storage device, on which a predefined time period is stored based on the battery current or...The decay time of the second contactor is stored as a function of when the first contactor opens. Alternatively, to interrupt the second current, e.g., the charging current, the second contactor can be opened by the evaluation unit, and only after a predefined time period and / or after the second current, e.g., the charging current, has decayed to a predefined value, can the first contactor be opened. Communication between the memory and the evaluation unit, or between the evaluation unit and the contactor, can take place, for example, via a bus system, e.g., a CAN bus system, and / or via other communication methods mentioned above.

[0011] According to a further advantageous embodiment of the present invention, the first contactor can be arranged in a positive path and the second contactor in a negative path of the circuit. Thus, a separate contactor is provided for each battery terminal.

[0012] According to a further advantageous embodiment, the contactor assembly also includes a pre-charging contactor at one pole. The pre-charging contactor is preferably also controlled by the evaluation unit. The pre-charging contactor is, for example, connected to a resistor so that when the traction battery is connected to the vehicle's electrical system, a comparatively small current initially flows, thus preventing damage to the components connected to the circuit, such as the power electronics of a vehicle. Preferably, the pre-charging contactor is arranged in parallel with the first and / or second contactor. Instead of a pre-charging contactor, a pre-charging relay is also possible, for example. Furthermore, a pre-charging contactor and / or a pre-charging relay can be arranged at either the positive or the negative pole.

[0013] According to a further embodiment of the contactor assembly according to the invention, the evaluation unit is further designed such that the first contactor opens to interrupt a first current, e.g., a discharge current, and / or the second contactor opens to interrupt a second current, e.g., a charging current, in response to one of the following conditions. A fault condition can, for example, include damage to a component present in the circuit. Furthermore, a fault condition, e.g., in the case of an arrangement of the contactor assembly within a battery, can include a reduction in insulation resistance and / or a short circuit. Such a condition can also be due to exceeding the protective current carrying capacity of the contactor. In this case, immediate opening must occur, as otherwise there is a risk that the closed contactor contacts will weld together and the contactor will thus be irreversibly damaged and cannot be opened.Furthermore, a contactor can be opened during commissioning to prevent damage to the components caused by excessively high current gradients. A contactor can also be opened during decommissioning, for example, when a battery is disconnected. Additionally, a contactor can be opened during a charging interruption to eliminate potential hazards for the user.

[0014] In a further advantageous embodiment of the contactor assembly according to the invention, the first and / or the second contactor can incorporate an inert gas for arc quenching. In this case, an inert gas can be introduced inside the contactor housing, for example, at low pressure, e.g., 1 to 2 bar, to further enhance arc quenching. Since inert gases are less ionizable than air, the inert gas contributes to arc quenching and thus to reduced damage to the contactor. Suitable inert gases include carbon dioxide, nitrogen, noble gases such as argon and / or helium and / or neon. Sulfur hexafluoride is also a particularly effective inert gas.

[0015] The following aspects of the invention encompass the advantageous embodiments and further developments as well as the general advantages of the device according to the invention and the associated technical effects.

[0016] According to a second aspect, the invention relates to a battery comprising the contactor assembly according to the first aspect. The battery can, for example, be a traction battery of a means of transportation. The contactor assembly can be arranged within the battery as a so-called "battery junction box".

[0017] According to a third aspect, the present invention relates to a photovoltaic unit comprising a contactor assembly according to the first aspect of the invention. Due to the necessity of installing contactors in photovoltaic units because of high voltages, arc suppression is also required when the contactors open. The contactor assembly according to the invention, which is arranged in the photovoltaic unit, can therefore significantly reduce contactor wear there as well. For example, a solar panel connected to the corresponding circuitry can serve as a photovoltaic unit. Photovoltaic systems on buildings can also serve as photovoltaic units.

[0018] According to a fourth aspect, the present invention relates to a means of transport comprising a contactor assembly according to the first aspect of the invention. For example, automobiles, in particular cars and / or trucks, and / or aircraft and / or ships and / or motorcycles, are suitable means of transport within the meaning of the invention. Preferably, the contactor assembly is arranged in the traction batteries of these means of transport.

[0019] A fifth aspect of the invention relates to a production line comprising a contactor assembly according to the first aspect of the invention. In particular, this refers to a production line with an electric drive in which contactors are also used.

[0020] Furthermore, a contactor is disclosed in which the orientation of the blow-out magnet is such that, compared to conventional contactors, it is rotated by 90° with respect to its vertical axis. In this case, the arc is deflected not towards the side walls, which in particular have an insulating material such as ceramic (i.e., the walls that extend only along one contactor contact), but towards the front and rear walls (i.e., the walls that extend along both contactor contacts). Such a device is disclosed in US 2,506,991.

[0021] Furthermore, an arrangement of this contactor in a contactor assembly comprising two contactors and an evaluation unit, which is configured to communicate with the contactors, is disclosed. Due to the special design of this contactor, it is bidirectional, meaning that it is always ideally able to extinguish the arc as quickly as possible, regardless of the current direction. Therefore, a first contactor can be such a bidirectional contactor, and a second contactor does not necessarily need to have a blow-out magnet. In such an arrangement, during both charging and discharging, the first contactor can be opened first, followed by the second contactor, to minimize wear. Brief description of the characters

[0022] Exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings. The drawings show: Fig. 1 a battery with state-of-the-art power electronics; Fig. 2. A safeguarding concept to prevent battery overload in accordance with the state of the art; Fig. 3a a contactor in accordance with the state of the art; Fig. 3b a visualization of the deflection of an electric arc within a contactor in accordance with the state of the art; Fig. 4 a battery with two identically oriented contactors according to the state of the art; Fig. 5 an embodiment of a battery according to the invention comprising an embodiment of the contactor assembly according to the invention, and Fig. 6 an embodiment of a means of transport according to the invention. Embodiments of the invention

[0023] Fig. Figure 1 shows, for better understanding of the invention, a battery 1 with connected power electronics 2, which may include, for example, an air conditioning compressor and / or a high-voltage auxiliary heater and / or a DC / DC converter. Battery cells 3 are also arranged in the battery 1. The battery 1 further includes a fuse 5, a current sensor 4, and an evaluation unit 6. The evaluation unit 6 communicates with the current sensor 4, the first contactor HS1, the second contactor HS2, and a pre-charging contactor S. VL .

[0024] Fig. Figure 2 shows a protection concept 7, as known from the prior art. This includes graphs of the switching threshold of the peak current 8a, the switching threshold of the continuous current 8b, the current-disconnecting capability 8c of the contactor, the short-circuit current 8d, the continuous current 8e of the battery, the current-carrying capacity 8f of the contactor, and the current-carrying capacity 8g of the fuse. The protection concept 7, represented by a coordinate system, shows the current I plotted against time t. The case of battery discharge with the time-limited peak current over a long period is marked by time t1. Time t2, on the other hand, marks the case of exceeding the current-carrying capacity 8f of the contactor, at which point the contactors must be opened immediately.

[0025] Fig. Figure 3a shows a perspective view of a contactor HS, as known from the prior art. The contactor HS comprises two contacts 10a and 10b, which are conductively connected to each other by an upward movement when the normally closed contact 13 is closed, causing current to flow through the contactor HS. When the contactor HS opens, the blow-out magnet 9 ensures arc quenching between contacts 10a, 10b and the normally closed contact 13.

[0026] Fig. Figure 3b shows the arc quenching process, as known from the prior art, in more detail. Here, when a contactor HS opens, an arc 11 is generated between the contacts 10a, 10b and the closing contact 13. An enlarged view of the arc 11 shows that it is directed by the blow-out magnet 9 (not shown here) to a side wall 12a or 12b of the contactor HS, thereby cooling it further and extinguishing it.

[0027] Fig. Figure 4 shows a battery 1 with power electronics 2 analogous to the Fig. 1. Here, the preferred direction 14a of the first contactor HS1 and the second contactor HS2 is shown. Current flows through contactors HS1 and HS2 in the preferred direction 14a. In the reverse case, i.e., when the current flows in the opposite direction, the arcs 11 are directed by the blow-out magnet 9 towards the center of the respective contactor by the resulting Lorentz force, which inevitably leads to welding or wear of the contacts 10a and 10b.

[0028] Fig. Figure 5 shows an embodiment of a battery 16 according to the invention. The battery 16 according to the invention comprises an embodiment of a contactor assembly 15 according to the invention. Here, the contactors HS1, HS2 have opposite preferred directions 14a, 14b. Due to the different preferred directions 14a, 14b, depending on whether the battery 16 is being discharged or charged, if it becomes necessary to open the contactor, the contactor through which a current flows in the preferred direction (e.g., 14a) can be opened first. Subsequently, the second contactor can be opened, thereby reducing the damage to the contacts 10a, 10b of the second contactor, since the current has usually decayed by the time the second contactor opens. This process is controlled by the evaluation unit 6. Thus, the assembly 15 according to the invention can control both a first current, e.g., a discharge current, and a second current, e.g.,a charging current is applied to the battery, whereby the contactor HS1, HS2, each operated in the preferred direction 14a, 14b, is opened to prevent arcing in the contactor that is operated against its preferred direction.

[0029] Fig. Figure 6 shows an embodiment of a means of propulsion 17 according to the invention, which has a battery 16 according to the invention as a traction battery. A contactor assembly 15 according to the invention is arranged inside the battery 16. Reference symbol list 1 battery (state of the art) 2 Power Electronics 3 battery cells 4 Current sensor 5 fuse 6 evaluation unit 7. Safeguarding concept 8a Switching threshold Peak current 8b Switching threshold continuous current 8c Current disconnection capability 8d Short-circuit current 8e Continuous current battery 8f Current carrying capacity contactor 8g current carrying capacity fuse 9 blow magnet 9a first blow magnet 9b second blow magnet 10a first contact 10b second contact 11 arcs 12a first side wall 12b second side wall 13 closing contacts 14a first preferred direction 14b second preferred direction 15 Protection assembly 16 Battery (embodiment according to the invention) 17 means of transport HS1 first shooter HS2 second contactor C ZK capacitor S VL Loading guard R VL Pre-charge contactor resistor

Claims

[1] Schütz assembly (15) comprising: • a first contactor (HS1) with a first blow magnet (9a), • a second contactor (HS2) with a second blow magnet (9b), and • one evaluation unit (6), wherein the first contactor (HS1) and the second contactor (HS2) each have a preferred current direction (14a, 14b) in which their respective blow-out magnet (9a, 9b) is able to extinguish an arc better than in a reverse current direction; wherein the first contactor (HS1) and the second contactor (HS2) are connected to each other in such a way that a first current flows through the first contactor (HS1) in the preferred current direction (14a) and through the second contactor (HS2) in the reverse current direction (14b), and the evaluation unit (6) is set up, • to interrupt the first current, open the first contactor (HS1) and then open the second contactor (HS2) and / or • to interrupt a second current, open the second contactor (HS2) and then open the first contactor (HS1). [2] Protection assembly according to claim 1, wherein the evaluation unit (6) is configured, • to open the first contactor (HS1) to interrupt the first current and only after a predefined time period and / or after the first current has decayed to a predefined value to open the second contactor (HS2). • to open the second contactor (HS2) to interrupt the second current and only to open the first contactor (HS1) after a predefined time period and / or after the second current has decayed to a predefined value. [3] Contactor assembly according to claim 1 or 2, wherein the first contactor (HS1) is arranged in a positive path and the second contactor (HS2) is arranged in a negative path of a circuit. [4] A guard assembly according to one of the preceding claims further comprising a preloading guard (S VL) at a pole. [5] Contactor assembly according to one of the preceding claims, wherein the evaluation unit (6) is further configured to interrupt the first contactor (HS1) for the first current and / or the second contactor (HS2) for the second current in response to • an error; and / or • exceeding the protective current carrying capacity (8f) of the contactor (HS1, HS2); and / or • commissioning; and / or • a decommissioning; and / or • a charging interruption; to open. [6] Contactor assembly according to one of the preceding claims, wherein the first contactor (HS1) and / or the second contactor (HS2) comprise an inert gas for arc quenching. [7] Battery (1) comprising a contactor assembly (15) according to any one of claims 1 to 6. [8] Photovoltaic unit comprising a contactor assembly (15) according to any one of claims 1 to 6. [9] Means of transport (17) comprising a guard assembly (15) according to any one of claims 1 to 6. [10] Production line comprising a guard assembly (15) according to any one of claims 1 to 6.

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