Pre-charging unit and battery system including the same

Abstract

The present invention relates to a pre-charging unit (10) for a battery system, the battery system comprising a plurality of battery cells for charging a DC link capacitor. The pre-charging unit (10) comprises a printed circuit board (20) having at least one conductive layer (22, 24). Furthermore, the pre-charging unit (10) comprises a pre-charging switch (30) mounted on the printed circuit board (20). Furthermore, a pre-charging resistor (40) is electrically connected in series with the pre-charging switch (30). The pre-charging resistor (40) is formed by conductive traces (42, 44) in the at least one conductive layer (22, 24) of the printed circuit board (20). Furthermore, a pre-charging circuit (80) and a battery system (100) are disclosed.

Description

Technical Field

[0001] The present invention relates to a pre-charging unit for a battery system, a pre-charging circuit and a battery system comprising the same, the battery system comprising a plurality of battery cells for charging a DC link capacitor. Background Art

[0002] In recent years, vehicles for transporting goods and people have been developed that use electricity as a source of motion. Such electric vehicles are cars driven by electric motors, using energy stored in rechargeable batteries. Electric vehicles can be powered by batteries alone, or can be in the form of hybrid vehicles powered by, for example, a gasoline generator in combination with an electric motor. Generally, an electric vehicle battery (EVB) or traction battery is a battery used to power the propulsion of a battery electric vehicle (BEV). Electric vehicle batteries are different from starting batteries, lighting batteries, and ignition batteries because they are designed to provide power for a sustained period of time. A rechargeable battery or secondary battery differs from a primary battery in that it can be repeatedly charged and discharged, while the latter only provides an irreversible conversion of chemical energy to electrical energy. Low-capacity rechargeable batteries are used as power sources for small electronic devices (such as mobile phones, laptops, and cameras), while high-capacity rechargeable batteries are used as power sources for hybrid vehicles and the like.

[0003] Typically, a rechargeable battery includes: an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; a housing that houses the electrode assembly; and electrode terminals electrically connected to the electrode assembly. An electrolyte solution is injected into the housing so that the battery can be charged and discharged by an electrochemical reaction of the positive electrode, the negative electrode, and the electrolyte solution. The shape of the housing, such as cylindrical or rectangular, depends on the intended use of the battery. Lithium-ion (and similar lithium polymer) batteries, widely known for their use in laptops and consumer electronics, dominate the most recently developed electric vehicles.

[0004] Rechargeable batteries can be used as a battery unit formed by connecting a plurality of battery cells in series and / or in parallel to provide high energy density, particularly for motor driving of hybrid vehicles. That is, a battery unit is formed by interconnecting electrode terminals of a plurality of unit cells according to the required amount of electricity and in order to realize a high-power rechargeable battery.

[0005] A battery pack is a group of any number of (preferably identical) battery cells. They can be connected in series, parallel, or a mix of series and parallel to deliver the desired voltage, capacity, or power density. The components of a battery pack include individual battery cells and the interconnects that provide conductivity between them.

[0006] In order to meet the dynamic power requirements of various power-consuming devices connected to the battery system, static control of battery power output and charging is not enough. Therefore, a stable information exchange between the battery system and the controller of the power-consuming device is required. This information includes the actual state of charge (SoC) of the battery system, potential electrical performance, charging capacity and internal resistance, and the actual or predicted power demand or surplus of the power-consuming device.

[0007] The battery system typically includes a battery management system (BMS) and / or a battery management unit (BMU) for processing the above information. The BMS / BMU can communicate with the controllers of various power-consuming devices through a suitable communication bus, such as an SPI or CAN interface. The BMS / BMU can further communicate with each battery subunit, in particular, with the battery monitoring circuit (CSC) of each battery subunit. The CSC can be further connected to the battery connection and sensing unit (CCU) of the battery subunit, which interconnects the battery cells of the battery subunit.

[0008] Thus, a BMS / BMU is provided for managing the battery pack, such as by protecting the batteries from operating outside of their safe operating area, monitoring their status, calculating secondary data, reporting that data, controlling their environment, validating them, and / or balancing them.

[0009] Conventionally, when a battery voltage source of a battery system comprising a plurality of battery cells is electrically connected to a load, before the main contactor / switch is closed, a so-called DC link capacitor is charged, which is connected in parallel to the load and between the battery system and the load. The reason for this is that the charged DC link capacitor prevents high current peaks during the closing of the main contactor. Such high current peaks can be very harmful to the contactor.

[0010] According to the prior art, an ohmic pre-charge resistor with a typical resistance of 10Ω to 100Ω is used and electrically interconnected between the battery voltage source (i.e., a plurality of connected battery cells) and the DC link capacitor. When the DC link capacitor is sufficiently charged, the main capacitor can be turned off and the current peak is reduced. The ohmic resistor is usually a high power device, usually packaged in ceramic. Alternatively, it can be formed as a copper wire wound on a ceramic core.

[0011] The problem with these known solutions is that the conventional pre-charge resistor consumes space, especially in the HV battery system housing. In addition, it requires separate wires and connectors to the busbars of multiple battery cells. This implementation also leads to higher costs.

[0012] Therefore, an object of the present invention is to overcome or reduce at least some of the disadvantages of the prior art and to provide a pre-charging unit and a battery system that can be compactly integrated to reduce volume space but still provide sufficient resistance to limit the switching current. Further objective problems to be solved will become clearer from the following description. Summary of the invention

[0013] Embodiments of the present disclosure seek to solve at least one problem existing in the prior art to at least some extent. Specifically, a pre-charging unit for a battery system is provided, the battery system comprising a plurality of battery cells for charging a DC link capacitor. The pre-charging unit comprises a printed circuit board having at least one conductive layer. The pre-charging unit further comprises a pre-charging switch mounted on the printed circuit board. The pre-charging unit comprises a pre-charging resistor electrically connected in series with the pre-charging switch. The pre-charging resistor is formed by a conductive trace in the at least one conductive layer of the printed circuit board.

[0014] The ohmic resistance of the conductive trace can be set or defined by the width, thickness and trace length of the resistive trace. These parameters can be pre-selected, i.e. selected during the manufacturing process, in order to customize the desired resistance value. The pre-charge switch can be a pre-charge relay for switching high voltages (e.g., more than 100V or more than, for example, 400V), in other words, the device mounted thereon can be attached thereto. The conductive trace can preferably be a copper trace, i.e., comprising copper. The conductive trace can also be referred to as a conductive track.

[0015] The technical advantage of the present invention is that the resistor is integrated in the printed circuit board together with the pre-charge switch, thereby reducing the space and cost for cables, because no separate resistor components and connecting cables are required. In particular, the present invention also uses the printed circuit board required for the pre-charge switch to implement the resistor. Therefore, the present invention provides an efficient use of the printed circuit board in combination with the pre-charge switch.

[0016] In a preferred embodiment, the conductive trace in the conductive layer may be formed to comprise a plurality of parallel arranged strip portions. The trace length of the conductive trace may be maximized in this way.

[0017] Preferably, the width of the conductive trace in the conductive layer is greater than the distance between two parallel strip portions. Thus, the trace length of the conductive trace can be increased, so that sufficient resistance can be obtained. In case the printed circuit board has a single conductive layer, a high footprint of the conductive trace relative to the printed circuit board can be achieved, for example higher than 50% or more.

[0018] In a preferred embodiment, the conductive trace may be formed to include a wrapped end portion electrically connecting two adjacent ribbon portions.A stable (ie, continuous) conductive trace is formed which meanders across an area of ​​the conductive layer.

[0019] Preferably, the winding end can be located at an edge portion of the printed circuit board. The trace length of the conductive trace can be increased, which can be used to achieve a higher resistance value. In other words, the positioning of the winding end can also be positioned at an edge portion of the conductive layer.

[0020] Preferably, the conductive trace of the pre-charge resistor can be thermally coupled to a cooling plate provided on at least one side of the conductive trace. Thus, a temperature rise and possible damage due to high temperature caused by resistive heating at the conductive trace can be prevented.

[0021] In a preferred embodiment, the printed circuit board may comprise at least two conductive layers, each conductive layer comprising conductive traces and the at least two conductive layers being arranged perpendicular to each other, wherein the pre-charge resistor is formed by the at least two conductive traces. Due to the two conductive layers, the trace length and therefore the resistance value of the conductive trace can be advantageously increased. In addition, the area occupied by the conductive traces for each conductive layer can be reduced.

[0022] Preferably, the conductive traces of different conductive layers are electrically connected in series by at least one conductive vertical interconnect unit, which vertically passes through at least one insulating layer interposed between the different conductive layers. The vertical interconnect unit can especially be a vertical interconnect channel, also known as a via or VIA. The concept of the vertical interconnect unit is thereby transferred so as to increase the resistance of the combined conductive traces by providing a direct connection through one or more insulating layers. Due to the vertical interconnect unit, the trace length and the resistance of the connected traces can be increased, or the area occupied by the conductive traces in each conductive layer can be reduced.

[0023] The at least one vertical interconnect unit may be located at the end of a conductive layer of the printed circuit board. The vertical interconnect unit located at the end allows for a maximum trace length in each conductive layer. Each conductive trace can be used optimally and a maximum resistance can be obtained.

[0024] In a preferred embodiment, each of the plurality of conductive layers including conductive traces may be two, or in an alternative embodiment, the number of each conductive layer including conductive traces may be an odd number. Two conductive layers may be a preferred embodiment, as complexity increases with the number of conductive layers. When the number of conductive layers is an odd number, the trace ends may be located at different ends of the printed circuit board. Thus, the conductive traces may be conveniently electrically coupled to, for example, a pre-charge switch.

[0025] In a preferred embodiment, the fraction of the occupied area of ​​the conductive layer occupied by the conductive traces compared to the area of ​​the conductive layer at the pre-charge resistor is less than 50%. Therefore, when two or more conductive layers are used, the trace length can be reduced, thereby also making the occupied area covered by the conductive traces have a smaller occupied density. For example, in the case of two conductive layers, the occupied area by the conductive traces can be, for example, 74cm 2 , but the present invention is not limited to this.

[0026] In another aspect of the present invention, a pre-charging circuit for charging a DC link capacitor is disclosed, comprising a pre-charging unit according to one of the above embodiments and a plurality of battery cells electrically connected to a pre-charging switch of the pre-charging unit.

[0027] In a preferred embodiment, the control unit can be configured to open the pre-charge switch of the pre-charge unit based on the charging time exceeding a predetermined charging time, wherein the predetermined charging time is based on the voltage of the battery cell and the resistance of the conductive trace. This allows preventing the conductive trace from overheating, thereby preventing the pre-charge resistor from overheating. In particular, it is understood that Joule heating will depend on the applied voltage of multiple battery cells and the selected resistance value of the resistive trace. The control unit can then calculate / determine the corresponding maximum charging time. This limited charging time may result in the DC link capacitor not being fully charged. However, it may be sufficient to prevent high current peaks while ensuring circuit integrity. For voltages above 100V or 400V, the maximum charging time may be less than 10 to 100ms, but the present invention is not limited to this.

[0028] In another aspect of the present invention, a battery system including a pre-charging circuit and / or a pre-charging unit may be provided. In particular, the main switch and the pre-charging unit may be connected in parallel.

[0029] According to another aspect of the present invention, a vehicle may include the battery system according to one of the above embodiments.

[0030] Further aspects of the invention can be gathered from the dependent claims or the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0032] Figure 1 A schematic diagram showing a pre-charging unit and a battery system according to an embodiment of the present invention is shown;

[0033] Figure 2 shows a top perspective view of a portion of a pre-charge resistor according to an embodiment of the present invention;

[0034] Figure 3 A perspective view showing a portion of a pre-charging unit according to another embodiment of the present invention; and

[0035] Figure 4 A side perspective view of a portion of a pre-charging unit according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0036] Reference will now be made in detail to embodiments, examples of which are shown in the accompanying drawings. Effects and features of exemplary embodiments and methods of implementing the same will be described with reference to the accompanying drawings. In the accompanying drawings, like reference numerals denote like elements, and redundant descriptions are omitted. When used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, when describing embodiments of the present invention, the use of "may" refers to "one or more embodiments of the present invention."

[0037] It will be understood that although the terms "first" and "second" are used 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, a first element may be named a second element, and similarly, a second element may be named a first element without departing from the scope of the present invention.

[0038] In the following description of the embodiments of the present invention, terms in the singular form may include plural forms unless the context clearly indicates otherwise.

[0039] It will be further understood that the terms “comprises,” “includes,” “including,” or “comprising,” indicate attributes, regions, fixed numbers, steps, processes, elements, components, and combinations thereof, but do not exclude other attributes, regions, fixed numbers, steps, processes, elements, components, and combinations thereof.

[0040] It will also be understood that when a film, region or element is referred to as being “on” or “over” another film, region or element, it can be directly on the other film, region or element or intervening films, regions or elements may also be present.

[0041] Here, the terms "upper" and "lower" are defined according to the z-axis. For example, the upper cover is located at the upper part of the z-axis, and the lower cover is located at the lower part thereof. In the accompanying drawings, the size of the elements may be exaggerated for clarity. For example, in the accompanying drawings, the size or thickness of each element may be arbitrarily displayed for the purpose of illustration, and thus the embodiments of the present invention should not be construed as being limited thereto.

[0042] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the scope of the present invention, the first element, component, region, layer or part described below may be referred to as a second element, component, region, layer or part.

[0043] It will be understood that when an element or layer is referred to as being “on,” “connected to” or “coupled to” another element or layer, it can be directly on, directly connected to or coupled to the other element or layer, or one or more intervening elements or layers may be present. Additionally, it will be understood that when an element or layer is referred to as being “between” two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers may also be present.

[0044] Figure 1 A schematic diagram of a battery system 100 according to an embodiment of the present invention is shown, which has a pre-charging circuit 80 and a pre-charging unit 10 integrated in the battery system 100 .

[0045] According to an embodiment of the present invention, Figures 2 to 4 The pre-charging unit 10 according to the present invention is described in more detail in FIG.

[0046] The battery system 100 may include a pre-charging circuit 80. The battery system 100 may further include a plurality of battery cells 110. For compactness, the plurality of battery cells 110 may be arranged in a plurality of Figure 1 A plurality of battery cells 110 may also be part of the pre-charge circuit 80 .

[0047] The battery system 100 may be accommodated in a battery housing 105. The battery system 100 may have electrical contacts C2, C1 to be electrically connected to and supply power to a load 140. In an embodiment, the load 140 may preferably be a motor, but the present invention is not limited thereto.

[0048] For exemplary purposes only, the inverter 130 may be interconnected between the electrical contacts C1, C2 and the load 140. The inverter 130 may convert the output voltage generated by the plurality of battery cells 110 into a voltage required by the corresponding load 140. The inverter 130 may be a DC / DC converter in this case.

[0049] The battery system 100 may be connected to an external DC link capacitor 120. In other words, the DC link capacitor may be an intermediate capacitor to the load 140. Figure 1 , the DC link capacitor 120 may be further electrically connected to a load 140, for example, via an inverter 130. Here, the DC link capacitor 120 may be electrically connected to electrical contacts C1, C2 of the battery system 100.

[0050] The battery system 100 may include a first main switch M1. The battery system 100 may further include a second main switch M2. In some embodiments, the second main switch M2 may be omitted. The main switches M1 and M2 may preferably be relays to switch high voltages, such as higher than 100V, higher than 400V, or higher. When the first main switch M1 or the first main switch M1 and the second main switch M2 are in a conductive state, i.e., a closed state, the main switch may electrically connect the plurality of battery cells 110 to the load 140. A control unit 70 may be provided, which is configured to control the switches M1 and M2. The control unit 70 may be a microcontroller. The microcontroller may be part of a battery management system.

[0051] When the external DC link capacitor 120 is sufficiently charged, the main switches M1, M2 can be closed without generating high current peaks that may damage or even destroy the main switch M1 or M2. In other words, the charged DC link capacitor 120 can prevent high current peaks when closing the first main switch M1 and / or the second main switch M2.

[0052] The charging of the DC link capacitor 120 must be performed in a previous step before the step of closing the main switches M1 , M2 .

[0053] Therefore, the battery system 100 includes an additional pre-charging circuit 80, which will be described in more detail below.

[0054] In particular, the battery system 100 and the pre-charging circuit 80 include a pre-charging unit 10 for charging a DC link capacitor 120. The pre-charging unit 10 and the first main switch M1 may be connected in parallel and electrically connected to a plurality of battery cells 110. In addition, according to a switching state of the first main switch M1 and a state of the pre-charging unit 10, the pre-charging unit 10 and the main switch M1 may be electrically connected to a node N1, which is electrically connected to an external DC link capacitor for charging the DC link capacitor 120, and is electrically connected to a load 140 for power supply.

[0055] The pre-charging unit 10 according to the present invention will now be described in more detail. The pre-charging unit 10 may include a pre-charging switch 30. The pre-charging switch 30 may be controlled by a control unit 70 to charge a DC link capacitor 120. The pre-charging switch 30 may be electrically connected to a plurality of battery cells 110. When a second switch M2 is provided, the second switch M2 may also be set to be turned on by the control unit 70 for pre-charging.

[0056] The pre-charging unit 10 according to the present invention comprises a printed circuit board 20, such as Figure 1 The pre-charging switch 30 is here mounted on or attached to the printed circuit board 20 .

[0057] In addition, the printed circuit board 20 includes conductive layers 22, 24, for example, see the disclosure of several embodiments of the present invention. Figures 2 to 4 In an embodiment, one or more conductive layers 22, 24 may be formed in the printed circuit board 20. In at least one conductive layer 22, 24, conductive traces 42, 44 are formed. Preferably, the conductive traces 42, 44 may be copper traces.

[0058] The pre-charge resistor 40 is formed by conductive traces 42, 44 in at least one conductive layer 22, 24 of the printed circuit board 20, such as Figure 1 Schematically indicated in FIG. 1 and will be more clearly shown in the following figures. A pre-charge resistor 40 formed by conductive traces 42, 44 is electrically connected in series with the pre-charge switch 30. The resistance value of each conductive trace 42 can be defined by its length, width and thickness.

[0059] According to the present invention, the resistor for limiting the current is integrated in the printed circuit board 20 together with the pre-charge switch 30. This means that a separate resistor does not have to be provided. In addition, there is no need to mount an additional resistor on the printed circuit board 20 and connect it to the wire. Therefore, the space and cost of the cable are reduced because a separate resistor component and a connecting cable are not required. Therefore, when the pre-charge switch 30 is mounted in the printed circuit board 20 and the resistor is implemented by a conductive trace, the printed circuit board 20 is used efficiently. Therefore, existing resources are effectively utilized. In particular, the battery housing 105 sets a specific volume for the internal space and components. This solution brings the advantage of compact space, which is very important when implementing a battery system in an application.

[0060] Figure 2 A cross section in a top perspective view of a printed circuit board 20 is shown in which a pre-charge resistor 40 used in a pre-charge unit 10 according to an embodiment of the present invention is formed. The cross section shows a conductive layer 22 of the printed circuit board 20. The conductive layer 22 includes a conductive trace 42 that forms the pre-charge resistor 40. In an embodiment, the conductive trace 42 may include copper.

[0061] In Figure 2 the present example, the printed circuit board 20 includes a conductive layer 22. However, the present invention is not limited thereto, for example, see Figure 3 and Figure 4 embodiments of

[0062] wherein more than one conductive layer 22, 24 is implemented.

[0063] It is noted that for a very high voltage of a plurality of battery cells 110, it means a high current. Therefore, for a higher voltage, a higher resistance is also required. Therefore, the present invention also aims to provide sufficient resistance to limit the current for a higher battery voltage as well. For example, the resistance can be about 10 Ω to 100 Ω or up to 1000 Ω, while voltages greater than 100 V or greater than 400 V can be used.

[0063] The conductive traces 42 in the conductive layer 22 can be formed to include a plurality of strip portions S1, ……, Sn arranged in parallel. Adjacent strip portions Si, Si+1 can carry currents having opposite directions to each other, where 1 < i < n-1. The strip portions S1, ……, Sn can constitute the main contribution to the resistance of the conductive trace 42, which results in an effective limitation of the current peak in response to the closing of the pre-charge switch 30.

[0064] Furthermore, in this example and also as Figure 3 shown, the width W of the conductive trace 42 in the conductive layer 22 can be greater than the distance D between two parallel strip portions Si, Si+1, where 1 < i < n-1. The space between adjacent strip portions Si, Si+1 can include an insulator 46, which electrically isolates the strip portions S1, ……, Sn from their adjacent strip portions. The short distance D means that only a narrow gap is generated between the strip portions S1, ……, Sn, and the trace length of the conductive trace 42 can be increased because the number of strip portions S1, ……, Sn of a fixed length can be higher. Therefore, the resistance length of the conductive trace 42 can be increased.

[0065] The conductive trace 42 can be further formed to include winding ends W1, ……, Wn. Each winding end W1, ……, Wn can electrically connect two adjacent strip portions Si, Si+1. The winding ends can have at least one bent portion or can be completely bent. The winding ends W1, ……, Wn can provide a 180-degree turn of the conductive trace 42. The winding ends W1, ……, Wn cause the conductive trace to meander over the entire area of the conductive layer 22. In particular, the winding ends W1, ……, Wn can be located at the edge portion ED of the printed circuit board 20. Furthermore, this feature can effectively utilize the available geometric area / space, in particular the width of the printed circuit board 20 and / or the conductive layer 22, to increase the trace length of each strip portion S1, ……, Sn, thus increasing the trace length of the conductive trace 42.

[0066] The conductive trace 42 can be formed so that, in the case of only one conductive layer 22, the fraction of the occupied area of ​​the conductive layer 22 / printed circuit board 20 occupied by the conductive trace 42 can exceed 50% in a top view compared to the area of ​​the conductive layer 22 at the pre-charge resistor 40. The area provided by the printed circuit board 20, in particular the conductive layer 22, can then be effectively used to form the resistance of the pre-charge resistor 40 according to the present invention.

[0067] Since the printed circuit board 20 according to the present embodiment includes only one conductive layer 22, the conductive trace 42 may include two trace ends TE1, TE2 on opposite sides for connecting the conductive trace 42 with the precharge switch 30 and connecting the wiring to the load 140. The trace ends TE1, TE2 may be located at opposite ends of the precharge resistor 40. The trace ends TE1, TE2 may be located at opposite sides with respect to the strip portions S1, ..., Sn and include the strip portions S1, ..., Sn therebetween, but the present invention is not limited thereto.

[0068] The pre-charging circuit 80 may include a plurality of battery cells 110. In addition, the pre-charging circuit 80 may include a control unit 70, which is configured to open (i.e., set to non-conductive) the pre-charging switch 30 of the pre-charging unit 10 based on the charging time exceeding the pre-charging time. That is, the conductive trace 42 on the printed circuit board 20 may be heated due to resistive heating. The predetermined charging time may be calculated based on the voltage of the plurality of battery cells 110 and the resistance of the conductive trace 42. The control unit 70 may be, for example, a microprocessor of a battery management system. The predetermined charging time may be in the range of less than 100 ms, preferably less than 50 ms or even less than 10 ms. Due to the personalized predetermined charging time, the charging time may be adjusted so that the risk of high temperature at the conductive trace 42 is reduced.

[0069] Figure 3 and Figure 4 A precharge resistor 40 according to another embodiment of the present invention is disclosed. In particular, Figure 3 A perspective view of the pre-charge resistor 40 is shown, and Figure 4 A side view of the pre-charge resistor 40 is shown.

[0070] In this preferred embodiment, the printed circuit board 20 may include two conductive layers 22, 24, wherein each conductive layer 22, 24 includes conductive traces 42, 44, such as Figure 3 and Figure 4 The pre-charge resistor 40 is formed by conductive traces 42, 44 so that a high resistance can be generated.

[0071] In other embodiments of the present invention, the number of conductive layers 22, 24 including conductive traces 42, 44 may be three or four, but the present invention is not limited thereto. The conductive layers 22, 24 may be arranged perpendicular to each other, such as Figure 3 and Figure 4 The pre-charge resistor 40 is then formed by two conductive tracks 42, 44. Each conductive track 42, 44 can in principle be connected in accordance with Figure 1 and Figure 2 The previously disclosed embodiments are formed in the same manner as the embodiments disclosed above.

[0072] The conductive traces 42, 44 of the two different conductive layers 22, 24 may be electrically connected in series. Then, the trace length of the common conductive traces 42, 44 may be approximately doubled. At least one conductive vertical interconnect unit 26 may be provided. In this case, three vertical interconnect units 26 are provided, but the present invention is not limited thereto. Figure 3 As seen in FIG. 1 , the vertical interconnect unit 26 may vertically pass through at least one insulating layer 25, which is interposed between the conductive layers 22, 24. The conductive layers 22, 24 may each include a conductive connector plate 28, to which the vertical interconnect unit 26 may be connected, respectively. The trace length of the conductive trace is then increased. This allows a higher resistance to be generated. In other words, the footprint of the conductive traces 42, 44 of each conductive layer 22, 24 may also be reduced due to the use of two traces.

[0073] The vertical interconnect units 26 may be located at the end portions EP of the conductive layers 22, 24. For example, each of the three vertical interconnect units 26 is formed at the end portions EP. Thus, the full conductive traces 42, 44 of each conductive layer 22, 24 may be used at full length.

[0074] In this embodiment, the trace ends T1, T2 may be located on the same side relative to the strip portions S1, ..., Sn of the conductive traces 42, 44, see Figure 4 In one embodiment of the present invention, the number of each conductive layer 22 including conductive traces 42 may be an odd number, such as 3, 5 or 7, or according to Figure 2 1. Then, the trace ends can be located on the opposite side, similar to Figure 1 shown.

[0075] Since more than one conductive layer 22 is used to provide resistance, the conductive layer 22 can be formed so that the fraction of the area of ​​the conductive layer 22 / printed circuit board 22 occupied by the conductive trace 42 in a plan view can be less than 50% compared to the area of ​​the conductive layers 22, 24 at the pre-charge resistor 40. Due to two or more conductive layers, in this embodiment, compared with the case of using only one conductive layer (see, for example, Figure 2), the trace length of each conductive layer 22, 24 can be reduced. The loss of trace length of each conductive layer 22, 24 is compensated by the series connection of conductive traces 42, 44 of different conductive layers 22, 24.

[0076] As in Figure 4 As can be seen in FIG. 1 , the conductive traces 42, 44 of the pre-charge resistor 40 are thermally coupled to the cooling plate 50. The cooling plate 50 may be disposed on at least one side of the conductive traces 42, 44. The pre-charge resistor 40 may be thermally coupled to the cooling plate 50 disposed on at least one side of the printed circuit board 20. Figure 4 As shown, such a cooling plate 50 may be placed on both sides of the printed circuit board 20 at least at the conductive traces 42, 44 to effectively transfer the heat generated by Joule heating when current is transmitted through the conductive traces 42, 44. The cooling plate 50 may also be used Figure 2 In the implementation mode, a high temperature state is prevented.

[0077] Reference Symbols

[0078] 10 pre-charge units

[0079] 20 PCB

[0080] 22 Conductive layer

[0081] 24 Conductive layer

[0082] 25 Insulation layer

[0083] 26 vertically interconnected units

[0084] 28 Connector Board

[0085] 30 Pre-charge switch

[0086] 40 pre-charge resistor

[0087] 42 conductive traces

[0088] 44 conductive traces

[0089] 46 Insulator

[0090] 50 cooling plates

[0091] 70 control unit

[0092] 80 Pre-charge Circuit

[0093] 100 battery system

[0094] 105 Shell

[0095] 110 battery cells

[0096] 120DC link capacitor

[0097] 130 Inverter

[0098] 140 load

[0099] C1 electrical contacts

[0100] C2 electrical contacts

[0101] N1 node

[0102] S1, ..., Sn band part

[0103] W1, ..., Wn winding end

[0104] ED edge part

[0105] WWidth

[0106] D distance

[0107] M1 main switch

[0108] M2 Main switch

[0109] EP end

[0110] TE1 trace end

[0111] TE2 trace end

Claims

1. A pre-charging unit (10) for a battery system comprising a plurality of battery cells, for charging a DC link capacitor, comprising: A printed circuit board (20) comprising at least one conductive layer (22, 24); a pre-charge switch (30) mounted on the printed circuit board (20); a precharge resistor (40) electrically connected in series with the precharge switch (30); and The printed circuit board (20) comprises at least two conductive layers (22, 24), each conductive layer (22, 24) comprises conductive traces (42, 44) and the at least two conductive layers (22, 24) are arranged perpendicular to each other, wherein the pre-charge resistor (40) is formed by the conductive traces (42, 44), The conductive traces (42, 44) of different conductive layers (22, 24) are electrically connected in series via at least one conductive vertical interconnect unit (26), and the at least one conductive vertical interconnect unit (26) vertically passes through at least one insulating layer (25) interposed between the different conductive layers (22, 24).

2. The pre-charging unit (10) according to claim 1, wherein: The conductive traces (42, 44) in the at least one conductive layer (22, 24) are formed to include a plurality of parallel-arranged strip portions (S1, . . . , Sn).

3. The pre-charging unit (10) according to claim 2, wherein: The conductive trace (42, 44) in the at least one conductive layer (22, 24) has a width (W) that is greater than the distance (D) between two parallel strip portions (S1, . . . , Sn).

4. The pre-charging unit (10) according to any one of claims 2 and 3, wherein the conductive trace (42, 44) is formed to include a winding end (W1, ..., Wn) electrically connecting two adjacent strip portions (S1, ..., Sn).

5. The pre-charging unit (10) according to claim 4, wherein the winding ends (W1, ..., Wn) are located at an edge portion (ED) of the printed circuit board (20).

6. The pre-charging unit (10) according to claim 1, wherein: The conductive traces (42, 44) of the pre-charge resistor (40) are thermally coupled to a cooling plate (50) disposed on at least one side of the conductive traces (42, 44).

7. The pre-charging cell (10) according to claim 1, wherein the at least one vertical interconnect cell (26) is located at an end portion (EP) of the conductive layer (22, 24).

8. The pre-charging unit (10) of claim 7, wherein the number of conductive layers (22, 24) is two and each conductive layer (22, 24) comprises a conductive trace (42, 44), or wherein the number of conductive layers (22) is an odd number and each conductive layer (22) comprises a conductive trace (42).

9. The pre-charging unit (10) according to claim 1, wherein: The fraction of the occupied area of ​​the conductive layer (22, 24) occupied by the conductive trace (42, 44) is less than 50% compared to the area of ​​the conductive layer (22, 24) at the conductive trace.

10. A pre-charging circuit (80) for charging a DC link capacitor, comprising a pre-charging unit (10) according to one of claims 1 to 9 and a plurality of battery cells (110) electrically connected to the pre-charging switch (30) of the pre-charging unit (10).

11. The pre-charging circuit (80) according to claim 10, comprising a control unit (70), which is configured to open the pre-charging switch (30) of the pre-charging unit (10) based on a charging time exceeding a predetermined charging time, wherein the predetermined charging time is based on the voltage of the plurality of battery cells (110) and the resistance of the conductive trace (42, 44).

12. A battery system (100) comprising the pre-charging circuit (80) according to one of claims 10 and 11.

13. A vehicle comprising the battery system (100) according to claim 12.

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