Battery management system, battery pack, and method for controlling the discharge of at least one battery cell

Abstract

The present invention relates to a battery management system, a battery comprising the battery management system, and a method for controlling the discharge of at least one battery cell. The battery management system (100) comprises a control circuit (102) configured to monitor the voltage of at least one battery cell (108) and a connector circuit (104) configured to electrically connect the control circuit (102) to the at least one battery cell (108). The control circuit (102) is mounted on a first component carrier (118) and comprises a first electronic interface having at least one contact (128) for electrically connecting a mating contact of the connector circuit. The connector circuit (104) comprises a second electronic interface having at least one mating contact for electrically contacting the at least one contact of the control circuit, at least one terminal (126) for electrically contacting a terminal of the at least one battery cell (108), and at least one balancing resistor (124) electrically connected between the at least one mating contact and the at least one terminal (126).

Description

[Technical Field]

[0001] The present invention relates to a battery management system, a battery comprising a battery management system, and a method for controlling the discharge of at least one battery cell.

[0002] As the development of electric vehicles (EVs), particularly battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs), and especially plug-in hybrid electric vehicles (PHEVs), progresses, high-voltage battery packs are increasingly being installed in vehicles such as buses, trucks, and passenger cars.

[0003] Typically, high-voltage battery packs used in electric vehicles consist of 80 to 300 battery cells connected in series and can provide high voltages ranging from 400 V to 1000 V. In future applications, even higher voltages may be provided by high-voltage battery packs. Such battery packs require a battery management system to measure cell voltages, perform cell balancing, and monitor cell temperatures to improve the usable capacity of the battery pack and extend the individual life of each cell. Throughout this specification, the terms "cell" or "battery cell" may refer to either a physical battery cell or multiple physical battery cells electrically connected in parallel at the cell level.

[0004] To measure and balance the voltage of each cell (hereinafter also referred to as "cell voltage"), a battery management system typically includes a specific integrated circuit called a cell monitoring IC. Figure 1 shows an example of a known battery management system. One or more cell monitoring ICs are typically soldered to a printed circuit board (PCB). Additionally, a filter circuit used to filter the cell voltage to add robustness against electromagnetic interference and a balancing resistor used to discharge specific battery cells to balance the voltages among the battery cells are also located on the PCB. Each of the one or more cell monitoring ICs typically measures 6 to 25 cells connected in series, although a larger number is also possible. Depending on the number and type of cell monitoring ICs used, peripheral circuits such as power supplies (linear transistors, DC / DC converters, etc.), communication interfaces (transformers, capacitors, etc.), and / or other capacitors and resistors are required. By soldering all of these components to the PCB, the PCB becomes an assembled printed circuit board (PCBA) 4.

[0005] To electrically connect the PCBA 4 to the battery cells 1 of the battery pack, a connection is established by a harness 2. The harness 2 may be formed, for example, of a wire harness with discrete wires (as shown schematically in FIG. 1 ), a PCB, or a flex circuit. The electrical connection between the harness 2 and the cells 1 is often achieved by using welding, soldering, wire bonding, screw connections, press-fit, or similar techniques. A connector 3 is often used to electrically connect the harness to the PCBA. Alternatively, the harness 2 may be connected to the PCBA 4 without the connector 3 and instead using screw connections, welding, soldering, or wire bonding.

[0006] For temperature measurement, one or more temperature sensors 5 can be used, for example in the form of NTC or PTC thermistors. The temperature sensors 5 are typically located inside the battery pack with good thermal coupling to the cells. The temperature sensors need to be connected to the electronics of the PCBA 4 to convert the temperature input from analog to digital and communicate the temperature to an external system 6 (typically an electronic control unit of an electric vehicle) on which the battery pack is mounted. The temperature sensors 5 are typically connected to the PCBA 4 using the same connector 3 or a separate connector.

[0007] The temperature sensor 5 may be soldered directly to the harness 2. Instead of using a connector, various types of temperature sensors may be wired directly to the PCBA 4 or connected by welding or soldering. The voltage across the temperature sensor is sampled by a cell monitoring IC along with the cell voltage measurement. It is also possible to have different cell monitoring ICs on the PCBA 4 for temperature and cell voltage measurements, especially if the temperatures of many different cells need to be measured. The measurement data, including cell voltage and cell temperature, is communicated digitally from the cell monitoring ICs to an external system 6.

[0008] However, the conventional battery management system has problems of requiring a large space and being heavy due to the large dimensions of the PCBA 4. Furthermore, the conventional battery management system is relatively expensive.

[0009] Therefore, there remains a need to provide an improved battery management system with a simplified circuit structure, which can save space and weight when incorporating the battery management system into a battery pack, and can provide for cost-effective assembly of the battery management system.

[0010] At least one of these objects is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0011] The present disclosure is based on the idea of ​​providing a battery management system comprising a control circuit configured to monitor a voltage of at least one battery cell and a connector circuit configured to electrically connect the control circuit to the at least one battery cell, the control circuit being mounted on a first component carrier and comprising a first electronic interface having at least one contact for electrically connecting with a mating contact of the connector circuit, the connector circuit comprising a second electronic interface having at least one mating contact for electrically connecting with the at least one contact of the control circuit, at least one terminal for electrically contacting a terminal of the at least one battery cell, and at least one balancing resistor electrically connected between the at least one mating contact and the at least one terminal.

[0012] That is, the present invention is based on the idea of ​​arranging the balancing resistor outside the first component carrier on which the control circuit of the battery management system is mounted, and directly incorporating the balancing resistor into a connector circuit that is arranged separately from the control circuit and electrically connects the control circuit to at least one battery cell. In this way, the balancing resistor becomes the largest resistance in the balancing current path and, as a result, becomes the main source of heat when discharging at least one battery cell, thereby improving the thermal characteristics of the control circuit. As a result, by arranging the balancing resistor outside the first component carrier, there is no need to deal with the heat generated by the balancing resistor, and all components of the control circuit can be integrated into a small component carrier, for example, a printed circuit board with a form factor of 20*40 mm or less.

[0013] The connector circuit is typically a large component because it electrically connects the control circuit and multiple battery cells. Therefore, integrating the balancing resistors into the connector circuit does not require additional cost or special consideration, and sufficient spacing between the balancing resistors electrically connected to different battery cells can be easily achieved. Therefore, heat dissipation during battery cell balancing can be achieved without adding a large area to the connector circuit.

[0014] Thus, the particular arrangement of balancing resistors of the present disclosure can significantly reduce the overall size, weight, and cost of the battery management system.

[0015] According to an embodiment of the present disclosure, the connector circuit is mounted on a second component carrier that is disposed separately from the first component carrier. However, it is also possible for the connector circuit to be provided in the form of a battery harness, with the balancing resistors being mounted within the harness.

[0016] Advantageously, the second component carrier can be a flexible printed circuit board, which allows for space-saving placement of the connector circuit and balancing resistors within a battery pack in which the battery management system is used.

[0017] Preferably, the at least one balancing resistor may be soldered to the second component carrier. Alternatively or additionally, the at least one balancing resistor may be formed of a metal trace provided on the second component carrier. For this purpose, one or more thin metal traces of a specific length and width may be etched onto the second component carrier, for example, or one or more thin metal traces of a specific length and width may be deposited onto the second component carrier. The one or more thin metal traces may be made of, for example, copper or aluminum, although other suitable conductive materials are also possible.

[0018] According to another advantageous embodiment, the first component carrier can be a printed circuit board, in particular a paper printed circuit board. In this way, the control circuit can be packaged together in a single, compact integrated component and directly integrated with the connector circuit. Since at least one balancing resistor is located outside the printed circuit board, the form factor of the integrated component can be 20 x 40 mm or smaller. Furthermore, paper printed circuit boards can be used to mount the integrated components, which can be more sustainable, more flexible, and less expensive than traditional printed circuit boards.

[0019] In order to protect the control circuitry from electrostatic discharge and to increase the robustness properties of the first component carrier, particularly in automotive applications, the first component carrier is preferably at least partially overmolded.

[0020] In another advantageous embodiment of the present disclosure, the second electronic interface can be a socket and the first electronic interface can be a pin strip, or the second electronic interface can be a PCI (Peripheral Component Interconnect) connector, particularly a PCIE (Peripheral Component Interconnect Express) connector or a miniPCIE connector, the first component carrier is adapted to mate with the PCI connector, and the first electronic interface is formed on the first component carrier so as to be able to contact the PCI connector.

[0021] In this case, the pin strip is welded, soldered, or glued to the first component carrier, and the socket, PCI connector, PCIE connector, or miniPCIE connector is welded, soldered, or glued to the second component carrier. Additional mechanical fixing means, such as brackets, clips, or screws, may be provided to strengthen the fixation between the first and second electronic interfaces.

[0022] In this manner, a cost-effective solution can be provided for incorporating the control circuitry directly into the connector circuitry as an integrated component, which can be mechanically mounted to the connector circuitry with minimal space and weight requirements, eliminating the need for heavy connectors. Furthermore, the control circuitry can be easily removed and replaced in the event of failure or adaptation to the configuration of battery cells in the battery pack in which the battery management system is used.

[0023] Alternatively or additionally, the first electronic interface may be welded to the second electronic interface to avoid the need for a heavy connector between the control circuitry and the connector circuitry and to integrate the control circuitry directly into the connector circuitry in a space-saving manner.

[0024] In another preferred embodiment of the present disclosure, the control circuit may include a microcontroller configured to measure a voltage of the at least one battery cell and control discharging of the at least one battery cell, a first conductor configured to electrically connect a first controller contact of the microcontroller to the at least one contact for measuring the voltage of the at least one battery cell, and a second conductor configured to electrically connect a second controller contact of the microcontroller to the at least one contact for discharging the at least one battery cell. Because the balancing resistor is located outside the control circuit, the second conductor can be manufactured with a low resistance in the range of a few ohms or milliohms, and discharging the at least one battery cell through the second conductor generates only a small amount of heat in the control circuit.

[0025] Preferably, the second conductor may have a predefined test resistance, and the microcontroller may be configured to measure a first voltage at the first controller contact and a second voltage at the second controller contact when discharging the at least one battery cell, and determine a balancing current through the balancing resistor based on the predefined test resistance and the difference between the measured first voltage and the measured second voltage. In this manner, the battery management system can directly determine the resistance value of the at least one balancing resistor and the duration required to discharge the at least one battery cell from the determined balancing current. Therefore, it is possible to compensate for a larger tolerance of the at least one balancing resistor introduced during manufacturing of the battery management system without resulting in insufficient cell balancing or malfunction. This is particularly useful when the at least one balancing resistor is provided as a thin metal trace on the second component carrier of the connector circuit.

[0026] In another preferred embodiment of the present disclosure, the control circuit further includes a communication unit configured to transmit electronic signals between the control circuit and an external system and / or a power supply unit configured to supply power to the controller. Alternatively or additionally, the first conductor may include a filter circuit configured to filter a voltage signal of the at least one battery cell when the microcontroller measures the voltage of the at least one battery cell. Further, alternatively or additionally, the connector circuit may include at least one temperature sensor, and the control circuit may be electronically connected to the at least one temperature sensor and configured to monitor the temperature of the at least one battery cell via the at least one temperature sensor.

[0027] In this way, the control circuitry can be packaged into a small integrated component that provides all the functionality required for measuring the battery cell voltage and temperature, as well as communicating with external systems such as a vehicle ECU, which can then be provided on a small printed circuit board with a form factor of 20*40mm or less and directly integrated into the connector circuitry using the connection methods described above.

[0028] The present disclosure also relates to a battery pack comprising at least one battery cell and an advantageous battery management system according to the present disclosure.

[0029] The present disclosure further provides a method for controlling discharge of at least one battery cell, the method comprising: measuring a first voltage using a first conductor electrically connected to a first contact of the control circuit while a balancing switch electrically connected in series with at least one balancing resistor between first terminals of the at least one battery cell is closed; measuring a second voltage using a second conductor electrically connected to the first contact while the balancing switch is closed; determining a balance current based on a difference between the measured first voltage and the measured second voltage; determining a resistance value of at least one balancing resistor (124) based on the determined balancing current; determining a balancing time based on the determined resistance value of the balancing resistor; discharging at least one battery cell for the determined balancing time; Equipped with.

[0030] Using this method, the resistance value of the at least one balancing resistor and the balancing time required to discharge at least one battery cell can be determined directly from the determined balancing current. Therefore, it is possible to compensate for larger tolerances of the at least one balancing resistor introduced during manufacturing of the battery management system without resulting in insufficient cell balancing or malfunction. This is particularly useful when the at least one balancing resistor is provided as a thin metal trace on the second component carrier of the connector circuit, further enabling cost, weight, and space savings during manufacturing of the battery management system. The tolerance of the resistance value of the at least one balancing resistor can be increased, for example, from 0.1% or 5% accuracy required in conventional systems to up to 40% accuracy in the battery management system disclosed herein.

[0031] The invention will now be described in more detail with reference to the accompanying figures and drawings, in which similar or corresponding details are provided with the same reference numerals.

[0032] The accompanying drawings are incorporated into and constitute a part of this specification to illustrate several embodiments of the present invention. These drawings, together with the description, serve to explain the principles of the present invention. The drawings are merely for illustrating preferred and alternative examples of how the present invention can be made and used, and should not be construed as limiting the present invention to only the embodiments shown and described. Moreover, several aspects of the embodiments can form solutions according to the present invention, individually or in different combinations. Thus, the embodiments described below can be considered alone or in any combination thereof. It should be kept in mind that the described embodiments are merely possible configurations, and that individual features, as described above, can be provided independently of one another or omitted entirely while practicing the present invention. Further features and advantages will become apparent from the following more particular description of various embodiments of the present invention, as illustrated in the accompanying drawings, in which like references refer to like elements. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 shows a schematic diagram of a battery management system according to the prior art. [Figure 2] FIG. 2 shows a schematic diagram of a battery management system according to a first embodiment of the present disclosure. [Figure 3] FIG. 3 shows a schematic circuit diagram of a battery management system according to a first embodiment of the present disclosure. [Figure 4] FIG. 4 shows a schematic perspective view of a control circuit according to a first embodiment of the present disclosure. [Figure 5] FIG. 5 shows a schematic perspective view of a second interface of a connector circuit according to a first embodiment of the present disclosure. [Figure 6] FIG. 6 shows a schematic perspective view of a connector circuit according to a second embodiment of the present disclosure. [Figure 7] FIG. 7 shows a schematic perspective view of a control circuit according to a second embodiment. [Figure 8] FIG. 8 is a schematic perspective view of a battery management system according to a second embodiment. [Figure 9] FIG. 9 shows a schematic circuit diagram of a battery management system according to a third embodiment of the present disclosure. [Figure 10] FIG. 10 shows a schematic flow chart of a method for controlling the discharge of at least one battery cell.

[0034] The present disclosure will now be further described with reference to the figures, and reference will now be made first to FIG. 2. FIG. 2 shows a schematic diagram of a basic concept of a battery management system 100 according to the present disclosure. The battery management system comprises a control circuit 102 and a connector circuit 104. The control circuit 102 is configured to monitor the voltage of battery cells 108 to which the control circuit 102 is electrically connected via the connector circuit 104. The battery cells 108 may form, for example, a battery configured to power the drivetrain of an electric or hybrid vehicle, or a battery used in a stationary energy storage system.

[0035] The control circuit 102 includes a microcontroller 106, which may be provided, for example, in the form of one or more cell monitor ICs. Each cell monitor IC can monitor the voltage of multiple battery cells 108 connected in series, e.g., 6 to 25 battery cells in a typical scenario. However, any one cell monitor IC may monitor the voltage of only one battery cell 108. Thus, monitoring the voltage of a battery cell 108 includes at least measuring the voltage of the battery cell 108 and may also include controlling the discharge of the battery cell 108 to balance the state of charge of the battery cell 108 with the state of charge of other battery cells 108 to which it is electrically connected. Optionally, monitoring the voltage of a battery cell 108 may also include measuring the temperature of the battery cell 108 by a temperature sensor 110 assembled in proximity to the battery cell 108. Thus, temperature measurement of the battery cell 108 may be performed by the same cell monitor IC or by a separate cell monitor IC specially adapted for temperature measurement that is also part of the microcontroller 106.

[0036] Additionally, the microcontroller 106 may optionally include a central processing unit (CPU) or memory, e.g., a non-volatile memory such as flash memory or EEPROM. The memory may store various programs that may be executed by the CPU to manage the battery cells 108 or an assembled battery that includes the battery cells 108. However, it is also possible for the microcontroller 106 to only include one or more cell monitoring ICs that can receive instructions from an external system 116, such as a vehicle's electronic control unit.

[0037] In addition to the microcontroller 106, the control circuit 102 may further include a filter circuit 112 for filtering the voltage signal of the battery cell 108 when measuring the cell voltage. The control circuit 102 may further include a plurality of peripheral circuits 114, such as a communication unit that enables communication between the control circuit 102 and an external system 116. The peripheral circuits 114 may further include a power supply unit that supplies power to the microcontroller 106, although it is also possible to supply power to the microcontroller 106 directly from a battery comprising the battery cell 108.

[0038] 2, the microcontroller 106, the filter circuit 112, and the peripheral circuit 114 are mounted on a first component carrier 118 to form the control circuit 102 as an integrated component. Here, the term integrated component means that all components necessary for measuring, in particular, the battery cell voltage and the battery cell temperature, optionally together with components necessary for communication with the external system 116, are packaged as a single compact component. Possible steps and methods for forming the control circuit 102 as an integrated component will be described later. As illustrated in FIG. 2, the connector circuit 104 may include a socket 120 for receiving a first electronic interface of the control circuit to electrically connect the control circuit 102 to the connector circuit 104.

[0039] The connector circuit 104 is configured to electrically connect the control circuit 102 to the battery cells 108. To this end, the connector circuit 104 includes a second electronic interface (not shown in FIG. 2 ) adapted to mate with the first electronic interface of the control circuit 102 to electrically connect the control circuit 102 and the connector circuit 104. The plurality of conductors 122, which may be, for example, wires or cables of a harness or wires or metal traces formed on a printed circuit board, electrically connect the second electronic interface to terminals of the connector circuit 104, which can be used to electrically contact the terminals of the battery cells 108.

[0040] According to the present invention, balancing resistors 124 are incorporated into the connector circuit 104 and are electrically connected by conductors 122 between the contacts of the second electronic interface and the terminals of the battery cells 108. As shown in the example of Figure 2, each terminal of the battery cells 108 may be electrically connected to the second electronic interface by a conductor 122 with a balancing resistor 124 and another conductor 122 without a balancing resistor 124, which can be used to measure the battery cell voltage more accurately. However, it is also possible for each terminal of the battery cells 108 to be electronically connected to the second electronic interface by only one conductor 122 with a balancing resistor 124 or by two or more balancing resistors 124.

[0041] 3 shows a schematic circuit diagram of the battery management system 100. In this example, the microcontroller 106 is configured to monitor the voltages of three battery cells 108 connected in series, and a balancing resistor 124 is electrically connected between each terminal 126 of the connector circuit 104 connectable to the terminals of the battery cells 108 and the second electronic interface of the connector circuit, resulting in four balancing resistors 124 being arranged in the connector circuit 104. Although only the conductor 122 with the balancing resistor 124 is shown in the connector circuit 104, there may be multiple conductors 122 electrically connected between each terminal 126 and the second electronic interface.

[0042] The control circuit 102 comprises a microcontroller 106 and a peripheral circuit 114 including a power supply unit 125, for example including linear transistors, DC-DC converters or similar suitable electronic components, which supplies a voltage signal (for example 3.3 V or 5 V) to the microcontroller 106. For this purpose, the power supply unit may be electrically connected to the battery cells 108 by means of separate contacts (not shown in FIG. 3 ), which may be part of the first electronic interface or may be arranged separately, in order to be supplied by the battery voltage formed by the battery cells 108.

[0043] The peripheral circuitry 114 may further comprise a communication unit 127, which may include, for example, a transformer, a capacitor, or similar suitable electronic components. The peripheral circuitry 114 may provide galvanic isolation for digital communication signals transmitted between the microcontroller 106 and an external system to which the microcontroller 106 is connected.

[0044] 3, the electronic interface of the control circuit 102 includes one or more contacts 128 connectable to mating contacts of a second electronic interface (not shown in FIG. 3) for electronically connecting the microcontroller 106 to each of the monitored battery cells 108. Two controller contacts of the microcontroller, a first controller contact 130 (the "c-pin") and a second controller contact 132 (the "s-pin"), are electrically connected to respective contacts 128 of the electronic interface. Of course, each first controller contact 130 and each second controller contact 132 can also be electrically connected to a different contact 128 of the first electronic interface.

[0045] Each c-pin 130 is electrically connected to a contact 128 via a first conductor 134, which may include a filter resistor 136. First conductors 134 electrically connected to different terminals of the same battery cell 108 via the connector circuit 104 may further be connected to each other via a filter capacitor. Using one or more analog-to-digital converters ("ADC converters") each electrically connected between two c-pins 130, the microcontroller can measure the voltage of each battery cell 108 between each two c-pins.

[0046] Meanwhile, each s-pin 132 is electrically connected to a contact 128 via a second conductor 138. Microcontroller s-pins 132 that are electrically connected to different terminals of the same battery cell 108 via the second conductor 138 and the connector circuit 104 may be electrically connected to each other by a balancing switch 140 of the microcontroller 106. The balancing switch 140 may be, for example, a MOSFET or other semiconductor switch.

[0047] By controlling the opening and closing of the balancing switch 140, the microcontroller 106 can control the discharge of each battery cell 108 via the balancing resistor 124 connected in series with the balancing switch 140. Because the balancing resistor is located outside the control circuit 102, the resistance value of the second conductor 138 can be reduced to a range of a few ohms, for example, less than 5 ohms, and more preferably less than 0.5 ohms, for example, 0.1 ohms or less. In particular, the resistance of the second conductor 138 can be smaller than the resistance of the first conductor 134 that constitutes the filter resistor 136, which typically has a resistance value of 100 ohms to 1 kilohm.

[0048] Therefore, the second conductor 138 generates a small amount of heat when discharging one of the battery cells 108 through the balancing resistor 124. This results in good thermal characteristics for the control circuit 102 and the first component carrier 118 on which the control circuit 102 is mounted, making it possible to integrate all components of the control circuit 102 into a small component carrier 118 having a form factor of, for example, 20*40 mm or less.

[0049] The first electronic interface of the control circuit 102 may further include contacts 142 that allow the microcontroller 106 to be electrically connected to one or more temperature sensors 110 disposed on the connector circuit 104. In this manner, the temperature of one or more battery cells 108 may also be measured by the microcontroller 106.

[0050] The connector circuit 104 may be mounted on a second component carrier (not shown in FIG. 3 ) that is preferably arranged separately from the first component carrier 118. Preferably, the second component carrier may be a flexible printed circuit board (also referred to as a flex circuit). Such a flexible circuit board may be formed from a flexible plastic substrate, typically polyimide, polyetheretherketone (PEEK), or transparent conductive polyester. In this case, the conductors 122 of the connector circuit 104 may be structured on the substrate by photolithography techniques or may be formed from metal strips (preferably copper or a copper alloy) with a thickness of 0.1 mm or less that are laminated between the plastic substrates.

[0051] A balancing resistor 124 is connected between each terminal 126 and a mating contact of the second electronic interface of the connector circuit 104. The resistance value of each balancing resistor 124 is typically in the range of 1 ohm to 100 ohms, preferably in the range of 20 ohms to 50 ohms. However, resistance values ​​higher than 100 ohms are also possible. Because the connector circuit 104 electrically connects the control circuit 102 to each battery cell 108, the flexible printed circuit board on which the connector circuit 104 is preferably mounted is a large component, and the balancing resistors 124 can be distributed at sufficient intervals on the flexible printed circuit board. Therefore, heat generated when discharging at least one of the battery cells 108 can be dissipated through one or more balancing resistors 124 without increasing the area of ​​the flexible printed circuit board.

[0052] The balancing resistors 124 may be, for example, soldered or welded to a flexible printed circuit board on which the connector circuit 104 is mounted. Alternatively, the balancing resistors 124 may be fabricated by etching elongated traces of conductors connecting each terminal 126 to a respective mating contact of the second electronic interface, or by depositing elongated metal traces, for example made of aluminum, copper, or other metal with suitable conductivity, onto the flexible printed circuit board to provide an electrical connection between each terminal 126 and a respective mating contact of the second electronic interface.

[0053] 4 shows an example of packaging the control circuit 102 as an integrated component. The microcontroller 106, along with a filter circuit 112 and optional peripheral circuits 114, is mounted on a printed circuit board (PCB) as a first component carrier 118. Optionally, a paper printed circuit board can be used as the first component carrier 118 to provide a sustainable, flexible, and cost-effective solution.

[0054] To mount the control circuit 102, the electronic components of the control circuit 102 may be welded, soldered, or mounted by other suitable methods to, for example, a printed circuit board serving as the first component carrier 118. A pin strip 144 is soldered to the underside of the printed circuit board 118 and functions as the first electronic interface, so that the contacts 128 (and 142) of the first electronic interface are provided in the form of pins. As shown in FIG. 4 , the pin strip 144 may be soldered to both elongated side edges of the PCB 118, although other arrangements of the pin strip 144 are also possible. FIG. 5 shows an exemplary socket 120 suitable for receiving the pin strip 144. The socket 120 may be welded, soldered, or glued to a flex circuit on which the connector circuit 104 is mounted, for example, to function as the second electronic interface of the connector circuit 104. Thus, in this example, mating contacts of the second electronic interface are provided in the form of receptacles in the socket 120.

[0055] By forming the first and second electronic interfaces in this manner, the assembled control circuit 102 can be pressed into the socket 120, and an electrical connection can be established between the control circuit 102 and the connector circuit 104 via the pin strip 144 and the socket 120. As a result, there is no need to provide an expensive and heavy automotive connector to establish such a connection, thereby significantly reducing the weight and cost of the battery management system 100. To further enhance the stability of the electrical connection between the control circuit 102 and the connector circuit 104, mechanical fastening means such as brackets, clips, or screws can be provided on either the pin strip 144 or the socket 120, or both.

[0056] A second example of packaging control circuit 102 as an integrated component and efficiently connecting it to connector circuit 104 is shown in Figures 6-8. Figure 6 shows a miniPCIE connector 246 that is secured to a flex circuit 148 on which connector circuit 104 is mounted and that serves as a second electrical interface for connector circuit 104. MiniPCIE connector 246 can be secured to flex circuit 148 by, for example, soldering, welding, or adhesive bonding.

[0057] FIG. 7 shows a state in which the control circuit 102 including the microcontroller 106 is mounted on a PCB (or a paper PCB) as a first component carrier 118 by, for example, welding or soldering. In the second embodiment, the PCB 118 is formed to have a shape that fits into the miniPCIE connector 246 shown in FIG. 6. The contacts 128 (and 142) for connecting with the mating contacts of the miniPCIE connector 246 are formed directly on the PCB 118. In this way, there is no need to provide an expensive and heavy connector on the PCB 118, and the control circuit 102 mounted on the PCB 118 can be directly inserted into the miniPCIE connector 246 as shown in FIG. 8. Furthermore, the control circuit 102 can be easily removed and retracted from the battery management system 100, and can be easily replaced in the event of a malfunction or a change in the battery cell configuration. In addition, in this embodiment, to strengthen the fixation between the miniPCIE connector 246 and the PCB 118, the miniPCIE connector 246, the PCB 118, or both may be provided with mechanical fixing means such as brackets, clips, or screws.

[0058] Alternatively in the second embodiment, any other type of PCIE or PCI connector may be mounted on the flex circuit 148 or any other type of second component carrier that may be used instead of the miniPCIE connector 246. The PCB 118 or other first component carrier 118 that may be used to mount the control circuit 102 may be configured to mate with and electrically connect to a PCIE or PCI connector of the type mounted on the second component carrier.

[0059] In addition to the mounting methods described above, the first component carrier 118 may optionally be at least partially overmolded to increase the stability of the control circuit 102 and to protect the electronic components of the control circuit 102 from electrostatic discharge.

[0060] In this regard, it is also possible to directly wire-bond and then overmold the electrical components without using a PCB as the first component carrier 118. In this example, the overmolded control circuit 102 may include weld tabs as contacts 128 of the first electronic interface, which may be welded directly onto the flex circuit on which the connector circuit 104 is mounted to establish an electrical connection between the wire-bonded control circuit 102 and the connector circuit 104. In this example, a space-saving solution is achieved because the control circuit 102 may be integrated directly onto the flex circuit on which the connector circuit 104 is mounted.

[0061] Notably, the described methods and embodiments for packaging the control circuit 102 into an integrated component are not only suitable for control circuit 102 in which the balancing resistors 124 are removed and placed in the connector circuit 104, but can also be applied to control circuit 102 that includes balancing resistors 124, as long as sufficient thermal management of the control circuit 102 can be achieved during discharge of the battery cells 108 through at least one of the balancing resistors 124.

[0062] FIG. 9 is a schematic circuit diagram of a second exemplary battery management system 200. The battery management system 200 largely corresponds to the battery management system 100 shown in FIG. 3. However, the battery management system 200 further includes at least one test resistor 150 as part of the second conductors 138. The test resistor 150 is electrically connected between each s-pin 132 and each respective contact 128 to which the s-pin 132 is electronically connected to enable discharging one of the battery cells 108. Knowing the resistance of the test resistor 150 allows the battery management system 200 to determine the resistance of the balancing resistor 124 when discharging the electrically connected battery cells 108. To avoid extensive heating in the control circuit 102 during discharging one of the battery cells, the resistance of the test resistor can be selected to be 2 ohms or less, more preferably 0.5 ohms or less, and even more preferably 0.1 ohms or less.

[0063] FIG. 10 shows a schematic flowchart of a method executed by the battery management system 200 for controlling the discharge of at least one battery cell 108, the method including determining a balancing resistance value of a balancing resistor 124 connected in series with at least one battery cell 108 (hereinafter referred to as the “battery cell 108 to be balanced”).

[0064] To determine the balancing resistance value, the microcontroller 106 closes the balancing switch 140 connected in series with the battery cell 108 to be balanced (step S102). After closing the balancing switch 140, the microcontroller 106 measures a first voltage at the c-pin 130 electrically connected to the terminal of the battery cell 108 to be balanced. Furthermore, the microcontroller 106 measures a second voltage at the s-pin 132 connected to the terminal of the battery cell 108 to be balanced by a voltage measurement device, such as an ADC, provided between the c-pin 130 and the s-pin 132 to enable redundant voltage measurement of the battery cell voltage at the c-pin 130 and the s-pin 132 (step S104).

[0065] Because the test resistor 150 is electrically connected in series with the balancing resistor 124 between the S-pin 132 and the contact 128, the first voltage and the second voltage differ by the voltage drop across the test resistor.

number

[0066] Determined equilibrium current I balance Based on this, the microcontroller 106 determines the resistance R of the balancing resistor 124. balance To this end, the microcontroller 106 measures a third voltage (cell voltage V of the battery cell 108 to be balanced) at the c-pin 130, which is electrically connected to the terminal of the battery cell 108 to be balanced, while the balancing switch 140 is open. cell Determine the equilibrium current I balance and the voltage difference between the third voltage and the first voltage, the microcontroller 106 determines the resistance R of the balancing resistor 124. balance of

number

[0067] In the next step (S112), the microcontroller 106 determines whether balancing of the voltage of the battery cell 108 to be balanced is required, i.e., whether the voltage of the battery cell 108 to be balanced exceeds the voltage of at least one of the other battery cells 108 by a predetermined amount. For simplicity, it is assumed below that cell balancing is performed only on the battery cell 108 to be balanced, but cell balancing may be performed on multiple battery cells 108 at the same time. If cell balancing is not required (NO in step S112), the method ends or returns to the start again, and the resistance value of the balancing resistor 124 may be determined again, for example, after a predetermined time has elapsed.

[0068] If cell balancing is required (YES in step S112), the microcontroller 106 starts discharging control of the battery cells 108 to be balanced. The cell balancing process may be initiated, for example, at the end of charging the battery pack when the battery cells 108 are about to reach a full charge state (100% SOC), or at the end of discharging the battery pack when the battery cells 108 are about to reach a minimum charge state.

[0069] The microcontroller 106 first calculates the determined resistance value R of the balancing resistor 124. balance The balancing time is determined based on the known balancing resistance and other parameters, such as the cell state of charge or the cell health status of the battery cells 108 to be balanced (step S114). A variety of different balancing techniques are known that can be used to determine the balancing time based on the known balancing resistance values. The microcontroller 106 then closes the balancing switches 140 and controls the discharge of the battery cells 108 to be balanced until the determined balancing time has elapsed from the start of discharge (step S116). Once the time equivalent to the balancing time has elapsed from the start of discharge, the microcontroller 106 determines that cell balancing is complete and opens the balancing switches 140 to stop the discharge of the battery cells 108 to be balanced.

[0070] By implementing the method for determining the resistance of balancing resistor 124 shown in FIG. 10 before cell balancing is performed, the required balancing time can be determined more accurately. Therefore, the tolerance of the resistance of balancing resistor 124 can be taken into account. In particular, the disclosed method can compensate for up to 40% of the tolerance of the resistance of balancing resistor 124, which is significantly greater than conventional systems that can only compensate for tolerances in the range of 0.1% to 5%. This is particularly interesting when balancing resistor 124 is fabricated as a thin metal trace on a second component carrier (e.g., flex circuit 148) on which connector circuit 104 is mounted, because fabricating thin metal traces results in greater tolerance variations.

[0071] Notably, the resistance value of balancing resistor 124 may be determined regardless of whether discharging one of the at least one battery cells 108 is required, or may be determined as part of a cell balancing process prior to discharging any of the battery cells 108. After the resistance value of balancing resistor 124 is determined in step S110, microcontroller 106 or external system 116 may store the determined resistance value of balancing resistor 124, for example, in non-volatile memory.

[0072] Instead of placing test resistor 150 on second conductor 138, it is also possible to implement a predetermined test current sink in parallel with second conductor 138 and measure a first voltage at s-pin 132 when the test current sink is OFF and a second voltage at s-pin 132 when the test current sink is ON. The balanced current and balanced resistance value can then be determined from the difference between the first and second voltages. Furthermore, instead of implementing the method for determining the balanced resistance value of at least one of balancing resistors 124 in microcontroller 106, the method may be performed by, for example, a vehicle electronic control unit supervising microcontroller 106. [Explanation of symbols]

[0073] [Table 1]

Claims

1. a control circuit (102) configured to monitor the voltage of at least one battery cell (108); a connector circuit (104) configured to electrically connect the control circuit (102) to at least one battery cell (108); Equipped with the control circuit (102) is mounted on a first component carrier (118); a first electronic interface having at least one contact (128) for electrically connecting a mating contact of the connector circuit; The connector circuit (104) a second electronic interface having at least one mating contact for electrically contacting said at least one contact of said control circuit; at least one terminal (126) for making electrical contact with a terminal of said at least one battery cell (108); at least one balancing resistor (124) electrically connected between the at least one mating contact and the at least one terminal (126); Equipped with The control circuit (102) includes a measurement circuit for measuring a battery cell voltage and a discharge control circuit for controlling discharge, the measurement circuit is electrically connected to the first electronic interface via a first conductor (134), and the discharge control circuit is electrically connected to the first electronic interface via a second conductor (138); Each pair of the first conductor (134) and the second conductor (138) is electrically connected to the same contact (128) corresponding to the corresponding battery cell (108).

2. 10. The battery management system (100) of claim 1, wherein the connector circuit (104) is mounted on a second component carrier located separately from the first component carrier.

3. The battery management system (100) of claim 2, wherein the second component carrier is a flexible printed circuit board (148).

4. The battery management system (100) of claim 2 or 3, wherein the at least one balancing resistor (124) is soldered to the second component carrier.

5. 4. The battery management system according to claim 2, wherein the at least one balancing resistor (124) is formed by a metal trace provided on the second component carrier.

6. The battery management system (100) according to any one of claims 1 to 3, wherein the first component carrier (118) is a printed circuit board, in particular a paper printed circuit board.

7. The battery management system (100) of any one of claims 1 to 3, wherein the first component carrier (118) is at least partially overmolded.

8. the second electronic interface is a socket (120) and the first electronic interface is a pin strip (144); or 4. The battery management system (100) of claim 1, wherein the second electronic interface is a Peripheral Component Interconnect (PCI) connector, in particular a Peripheral Component Interconnect Express (PCIE) connector or a miniPCIE connector (246), the first component carrier (118) is adapted to mate with the PCI connector, and the first electronic interface is formed on the first component carrier (118) so as to be able to contact the PCI connector.

9. The battery management system (100) of any one of claims 1 to 3, wherein the first electronic interface is welded to the second electronic interface.

10. The control circuit (102) a microcontroller (106) configured to measure the voltage of the at least one battery cell (108) and to control the discharge of the at least one battery cell (108); a first conductor (134) configured to electrically connect a first controller contact (130) of the microcontroller (106) to the at least one contact for measuring the voltage of the at least one battery cell (108); a second conductor (138) configured to electrically connect a second controller contact (132) of the microcontroller to the at least one contact for discharging the at least one battery cell (108); The battery management system (100) of any one of claims 1 to 3, comprising:

11. the second conductor (138) has a predefined test resistance (150); 11. The battery management system of claim 10, wherein the microcontroller is configured to measure a first voltage at the first controller contact and a second voltage at the second controller contact when discharging the at least one battery cell, and to determine a balancing current through the balancing resistor based on a resistance of the test resistor and a difference between the measured first voltage and the measured second voltage.

12. The control circuit (102) a communication unit (127) configured to transmit electronic signals between the control circuit (102) and an external system (116); and / or a power supply unit (125) configured to supply power to said microcontroller (106); and / or 11. The battery management system (100, 200) of claim 10, wherein the first conductor comprises a filter circuit (112) configured to filter a voltage signal of at least one battery cell (108) when the microcontroller (106) measures the voltage of the at least one battery cell (108).

13. the connector circuit (104) includes at least one temperature sensor (110); the control circuit (102) is electronically connected to the at least one temperature sensor (110) and configured to monitor the temperature of the at least one battery cell (108) via the at least one temperature sensor (110); The battery management system according to claim 1 .

14. A battery pack comprising at least one battery cell (108) and a battery management system (100, 200) according to any one of claims 1 to 3.

15. A method for controlling discharge of at least one battery cell (108) using the battery management system of claim 1, comprising: measuring (S104) a first voltage while a balancing switch (140) electrically connected in series with at least one balancing resistor (124) between first terminals of at least one battery cell (108) is closed, using a first conductor (134) electrically connected to a first contact (128) of the control circuit (102); measuring (S104) a second voltage using a second conductor (138) electrically connected to the first contact (128) while the balancing switch (140) is closed; determining a balance current based on a difference between the measured first voltage and the measured second voltage (S106); determining (S110) a resistance value of at least one balancing resistor (124) based on the determined balancing current; determining a balancing time based on the determined resistance value of the balancing resistor (124) (S114); Discharging (S116) at least one battery cell (108) for the determined balancing time; A method for providing the above.

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