Power System

Abstract

The present disclosure relates to a power supply system (100). The power supply system (100) includes a high-voltage battery pack (110) including a plurality of battery modules (102) electrically connected in series to form the high-voltage battery pack (110) and configured to output a predetermined high voltage as a sum of module voltages provided by the plurality of battery modules (102), low-voltage output terminals (116a, 116b) configured to output a predetermined low voltage to at least one electrical load, and a voltage converter network (106) configured to electrically isolate the low-voltage output terminals (116a, 116b) from the high-voltage battery pack (110) and convert at least a portion of the module voltage to the predetermined low voltage. The voltage converter network (106) comprises at least one voltage converter (108) and a controller configured to control the operation of the at least one voltage converter, wherein the at least one voltage converter (108) is electrically connected to at least one of the plurality of battery modules (102) and configured to convert a module voltage supplied by the at least one of the plurality of battery modules (102) to a predetermined low voltage and output the predetermined low voltage as an output voltage to the low voltage output terminals (116a, 116b).

Description

[Technical Field]

[0001] The present disclosure relates to a power supply system that can output a predetermined high voltage to an electric load such as an electric motor of an electric vehicle, and output a predetermined low voltage to another electric load. [Background technology]

[0002] With the advanced development of electric vehicles, especially battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), high-voltage battery packs are increasingly being installed in vehicles such as buses, trucks, and passenger cars. High-voltage battery packs used in electric vehicles typically consist of 80 to 300 battery cells connected in series and are used to power the electric vehicle's high-voltage system, including, for example, the electric motor, providing a high voltage in the range of 400V to 1000V. In the future, even higher voltages may be supplied from high-voltage battery packs.

[0003] In addition to the high-voltage battery pack, a low-voltage auxiliary battery, typically 12 V or 24 V, is connected to the low-voltage bus. The low-voltage auxiliary battery acts as an energy reservoir to power electrical loads such as the vehicle's air conditioning and lighting systems.

[0004] For this purpose, as shown in Fig. 1, for example, an auxiliary battery 10 is provided via a DCDC voltage converter 20, which is electrically connected to a high-voltage bus 30. The high-voltage bus 30 is electrically connected to the terminals of a high-voltage battery 40, and a high voltage is supplied from the high-voltage battery 40. Contactors 50a, 50b are arranged between the terminals of the high-voltage battery 40 and the DCDC voltage converter 20, and can be opened to cut off the power supply to the high-voltage bus 30, for example, when the electric vehicle is powered off or when a high-voltage short circuit occurs. Therefore, the auxiliary battery 10 not only balances the load and demand of a low-voltage bus 60 electrically connected to the auxiliary battery 10, but also functions as an energy reservoir for the electrical loads connected to the low-voltage bus 60 when the electric vehicle is powered off. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inventors of the present invention have discovered that the high input voltage supplied by the high-voltage battery pack and the high output current supplied by the low-voltage bus place significant stress on the components of the DC-DC converter, causing them to deteriorate significantly. Furthermore, the typical auxiliary battery used in conventional systems is expensive, heavy, and requires a large amount of space in a secure location inside the vehicle.

[0006] Therefore, there is a need to provide a power supply system with a simplified structure that can overcome these drawbacks and reduce stress on the circuit components of the power supply system. Furthermore, there is a need to provide a space-saving and cost-effective solution. [Means for solving the problem]

[0007] At least one of these objects is solved according to the invention by the independent claims.

[0008] In particular, according to aspects of the present disclosure, a power supply system includes a high-voltage battery pack including a plurality of battery modules electrically connected in series to form the high-voltage battery pack and configured to output a predetermined high voltage as a sum of module voltages supplied by the plurality of battery modules, a low-voltage output terminal configured to output a predetermined low voltage to at least one electrical load, and a voltage converter network configured to electrically isolate the low-voltage output terminal from the high-voltage battery pack and convert at least a portion of the module voltage to the predetermined low voltage. The voltage converter network includes at least one voltage converter and a controller configured to control operation of the at least one voltage converter, the at least one voltage converter being electrically connected to at least one of the plurality of battery modules and configured to convert the module voltage supplied by the at least one of the plurality of battery modules to the predetermined low voltage and output the predetermined low voltage as an output voltage to the low-voltage output terminal.

[0009] That is, the present disclosure is based on the idea of ​​connecting a voltage converter directly to a battery module of a high-voltage battery, i.e., to a portion of the high-voltage battery, so that the input voltage supplied to the voltage converter is a fraction of the predetermined high voltage supplied by the high-voltage battery pack, thereby significantly reducing the desired voltage conversion ratio of the voltage converter and the voltage stress applied to the input semiconductors of the voltage converter.

[0010] Furthermore, at least one voltage converter is electrically connected directly to at least one connection node of the battery modules of the high-voltage battery, and is not necessarily connected to the high-voltage bus of the power supply system. As a result, the specific configuration of the power supply system according to the present disclosure allows power to be supplied from the input side to the output side via the converter network even when the contactor provided on the high-voltage bus is open, eliminating the need to store energy in an auxiliary battery connected to the low-voltage bus of the electric vehicle. This eliminates the need to provide a heavy auxiliary battery for storing energy in the power supply system.

[0011] In an advantageous aspect of the present disclosure, the voltage converter network includes a plurality of voltage converters, each of which is electrically connected to at least one of the plurality of battery modules and configured to convert a module voltage supplied by the at least one of the plurality of battery modules to a predetermined low voltage and output the predetermined low voltage as an output voltage to a low-voltage output terminal.

[0012] That is, the present disclosure provides an advanced, redundant network of voltage converters electrically connected to the individual battery modules of a high-voltage battery pack. This distributed configuration of the voltage converter network provides higher efficiency in voltage conversion, reduces design complexity, and significantly reduces volume and weight compared to using a single auxiliary battery as the energy source for the low-voltage bus of an electric vehicle.

[0013] Preferably, the voltage converters are connected in parallel to one another in a voltage converter network, so that the voltage converters can function as independent low-voltage power supplies for the electrical loads electrically connected to the low-voltage terminals of the power supply system. This parallel configuration allows the power supply system to operate even if one or more of the voltage converters fail. In this way, continuous power supply to the safety-critical electrical loads electrically connected to the low-voltage terminals can be ensured.

[0014] In another advantageous aspect of the present disclosure, multiple voltage converters are electrically connected to the same number of battery modules. This allows each voltage converter to receive the same input voltage, i.e., a voltage that is a multiple of the module voltage. The number of battery modules to which each of the multiple voltage converters is electrically connected is preferably one, so that the input voltage can be reduced to the module voltage of one battery module. For example, when n battery modules are electrically connected in series to form a high-voltage battery pack, the module voltage may be given as (HV / n), where HV represents a predetermined high voltage of the high-voltage battery pack. In this example, each voltage converter can reduce the input voltage by a factor n compared to the conventional case in which the full high voltage HV of the battery pack is used as the input voltage of a single voltage converter.

[0015] To enable the voltage converters to rapidly respond to load demands of electrical loads electrically connected to the low-voltage output terminals and supplied by the voltage converter network, at least one voltage converter may each include a measurement circuit configured to measure an actual output voltage of the voltage converter, and a microcontroller configured to adjust the output voltage of the voltage converter based on the measured actual output voltage.

[0016] Preferably, to enable centralized control of the management of the loads of a plurality of voltage converters, at least one voltage converter each comprises a communication circuit configured to communicate its measured actual output voltage to a controller of the voltage converter network.

[0017] In another advantageous aspect of the present disclosure, the controller of the voltage converter network is configured to activate or deactivate each of the at least one voltage converter. Preferably, the controller may be configured to activate or deactivate each of the at least one voltage converter based on the overall load electrically connected to the low-voltage output terminals and / or based on the state of charge of at least one battery module to which each voltage converter is electrically connected. This allows the present disclosure to rapidly respond to the power demands of the electrical loads electrically connected to the low-voltage output terminals and supplied by the voltage converter network. Furthermore, this configuration allows module voltage balancing of the battery modules at the module level without the need for balancing resistors to dissipate energy.

[0018] In another advantageous aspect of the present disclosure, at least one voltage converter is provided on a printed circuit board provided as part of a battery management system of a high-voltage battery pack. For example, each voltage converter may be located on a charge monitoring board (CMB) provided in the battery management system of the battery to monitor the charge and / or temperature of one or more of the battery modules. In this manner, the present disclosure enables communication between the multiple voltage converters and the voltage converter controller using communication lines provided in each CMB.

[0019] In another advantageous aspect of the present disclosure, a voltage converter network is configured to generate an excitation signal for electrochemical impedance spectroscopy (EIS) of at least one of the plurality of battery modules. The generated current for EIS electrochemical impedance spectroscopy (EIS) can be directly consumed by an electrical load electrically connected to the low-voltage output terminals and supplied by the voltage converter network, thereby avoiding power losses in switch resistances used in conventional EIS. Furthermore, reactive electrical components within each voltage converter can generate a current sine wave with lower total harmonic distortion (THD) compared to excitation signals generated using conventional methods, thereby reducing the data processing load required to analyze the results of the impedance measurement and improving the accuracy of the impedance measurement.

[0020] To supply a predetermined low voltage to the at least one electrical load, the power supply system may further comprise a low voltage bus configured to electrically connect the low voltage output terminal to the at least one electrical load.

[0021] Optionally, for further energy optimization, the low-voltage bus may comprise a first low-voltage supply line and a second low-voltage supply line, which may optionally supply different classes of electrical loads, thereby allowing to classify electronic components in classes of electrical loads according to their energy demands and / or safety features.

[0022] To reduce the required voltage conversion ratio of at least one voltage converter of the voltage converter network and to optimize the voltage stress applied to the input semiconductors of the at least one voltage converter, the module voltage supplied by each battery module is in the range of 30 V to 60 V. That is, the high-voltage battery pack is divided into units of battery modules, each supplying a module voltage of 30 V to 60 V, to which the voltage converters of the voltage converter network can be electrically connected.

[0023] In certain advantageous aspects of the present disclosure, the high-voltage battery pack is a traction battery configured to power the motor of an electric vehicle, and in such an application, the low-voltage auxiliary battery traditionally used as a low-voltage power source for the electric vehicle can be replaced by a voltage converter network connected directly to a single battery module of the high-voltage battery.

[0024] In this specification, the term "high voltage" refers to a voltage in the range of more than 200 V, preferably in the range of 400 V to 1000 V, and the term "low voltage" refers to a voltage in the range of 0 V to 100 V, preferably in the range of 0 V to 50 V.

[0025] Additionally, the term "terminal" is intended to refer to a point at which a conductor from a power source, such as a battery pack or battery, an electrical device, an electrical circuit, an electrical component, or an electrical load terminates and a point is provided for electrically connecting a power source, an external electrical device, an external electrical circuit, an external electrical component, or an electrical load to the conductor. The term "node" or "connection node" is intended to refer to a connection point of the terminals of one or more circuit components, and may also refer to the entire electrical wire conductively coupling the terminals of one or more electrical circuit components.

[0026] The present invention will now be described in more detail with reference to the accompanying drawings, in which like or corresponding details are designated with the same reference numerals, and in which: [Brief explanation of the drawings]

[0027] The accompanying drawings are incorporated herein and form a part of this specification to illustrate several aspects of the present disclosure. These drawings, together with the description, serve to explain the principles of the present invention. The drawings merely illustrate preferred alternatives for how to make and use the invention and should not be construed as limiting the invention to only the aspects shown and described. Furthermore, several aspects can form solutions according to the present disclosure individually or in different combinations. Thus, the aspects described below can be considered either alone or in any combination thereof. It should be noted that the described aspects 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 aspects, as illustrated in the accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of a prior art power supply system. [Figure 2] FIG. 2 is a schematic diagram of a power supply system according to one embodiment of the present disclosure. [Figure 3] FIG. 3 is another schematic diagram of a power supply system according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present disclosure will now be described in more detail with reference to the drawings. First, reference is made to FIG. 2, which is a schematic circuit diagram of a power supply system 100 illustrating the effects of the present disclosure. In the exemplary application described below, the power supply system 100 is used to power electrical loads, such as electric motors in an electric vehicle, that are supplied at a predetermined high voltage, and electrical loads, such as air conditioning systems and lightning systems, that are supplied at a predetermined low voltage. However, the power supply system 100 can also be used in other energy storage systems that supply electrical loads at different voltage levels, including at least one predetermined high voltage level and at least one predetermined low voltage level.

[0029] The power supply system 100 includes a high-voltage battery pack 110 (sometimes referred to herein as a high-voltage battery 110) that functions as an energy storage for outputting a predetermined high voltage to a predetermined high-voltage bus 112 that is electrically connected to a high-side terminal and a low-side terminal of the battery pack 110 and can supply the predetermined high voltage to an electric motor of a vehicle. Contactors 114a and 114b are disposed on the high-voltage bus 112. In this example, the contactor 114a may be electrically connected to the high-side terminal of the high-voltage battery pack 110, and the contactor 114b may be electrically connected to the low-side terminal of the high-voltage battery pack 110. Opening and closing the contactors 114a and 114b can supply or interrupt power from the high-voltage battery pack 110 to the electric motor via the high-voltage bus 112.

[0030] The high-voltage battery pack 110 includes a plurality of battery modules 102, which are connected in series at connection nodes 104 to form the high-voltage battery pack 110. In Fig. 2, the N battery modules 102 are designated as battery modules 102(1), 102(2), ..., 102(N) from the lower low-potential side of the high-voltage battery pack 110 toward the upper high-potential side, for ease of identification.

[0031] The multiple battery modules 102 are subunits of the high-voltage battery pack 110, and supply a module voltage that sums to a predetermined high voltage output from the high-voltage battery pack 110 to the high-voltage bus 112. That is, if N is the number of battery modules 102, the value of the module voltage supplied by each battery module 102 can be obtained by dividing the predetermined high voltage value output from the high-voltage battery pack 110 by N. For example, if the battery pack 110 outputs a predetermined high voltage value of 800V and N=20, the battery modules 102 share and output a module voltage of (800V / 20)=40V.

[0032] Each battery module 102 includes a plurality of battery cells electrically connected in series. The battery cells may be physical battery cells or may include a plurality of physical battery cells electrically connected in parallel at the cell level. As an example, each battery module 102 may be formed by electrically connecting 12 to 14 battery cells, each having a cell voltage of 3.3V to 4.3V, in series. Thus, in this example, each battery module 102 may provide a module voltage of 30V to 60V. However, other predetermined numbers of battery cells having other predetermined cell voltages may be electrically connected to form a battery module 102 to provide a smaller or larger module voltage.

[0033] To supply a predetermined low voltage to some electrical loads in addition to the predetermined high voltage supplied to the vehicle's electric motor, the power supply system 100 includes a voltage converter network 106. The voltage converter network 106 is configured to convert at least a portion of the module voltage supplied by the battery modules 102 to a predetermined low voltage, for example, 12 V or 24 V. Furthermore, the voltage converter network 106 electrically isolates the high-voltage battery pack 110 from a low-voltage bus 120 that is configured to supply the electrical loads at the predetermined low voltage.

[0034] The voltage converter network 106 includes voltage converters 108. In Fig. 2, the M voltage converters 108 are designated as voltage converters 108(1), 108(2), ..., 108(M) from the lower low-potential side to the upper high-potential side of the high-voltage battery pack 110 in order to distinguish them from one another.

[0035] 2, in the illustrated example, the total number M of voltage converters 108 may be set equal to the total number N of battery modules 102, and each voltage converter 108 may be electrically connected to the connection node 104 of one of the plurality of battery modules 102. In this way, each voltage converter 108 converts the module voltage of one of the plurality of battery modules 102 into a predetermined low voltage.

[0036] However, the total number M of voltage converters 108 in the voltage converter network 106 does not necessarily have to be equal to the total number N of battery modules 102 in the high-voltage battery pack 110. For example, the number M may be smaller than the number N, and each voltage converter 108 may be electrically connected to two or more of the battery modules 102 and convert an input voltage that is the sum of a portion of the module voltages. Here, it is preferable that each voltage converter 106 be electrically connected to the same number of battery modules 102 to equalize the input voltages of the voltage converters 108. This simplifies the control of the voltage converters 108, as will be described later. Furthermore, it should be noted that all N battery modules 102 do not necessarily have to be connected to one of the voltage converters 108.

[0037] For example, the voltage converter network 106 may include one voltage converter 108 electrically connected to one of the battery modules 102 or to two or more of the battery modules 102. As another example, the voltage converter network 106 may include two voltage converters 108 electrically connected to two different battery modules 102, with the other N-2 battery modules 102 not electrically connected to a voltage converter.

[0038] As described above, the module voltage of one of the battery modules 102 is only a portion of the predetermined high voltage output by the high voltage battery pack 110. Thus, by electrically connecting each voltage converter 108 to only one or a portion of the multiple battery modules 102, the input voltage applied to the voltage converter 108 can be significantly reduced, reducing the voltage conversion ratio of the voltage converter 108 and the voltage stress applied to the input semiconductors of the voltage converter 108.

[0039] 2 , in the voltage converter network 106, the voltage converters 108 are electrically connected in parallel with each other and function as parallel power supplies for a low-voltage bus 120 electrically connected to the voltage converter network 106 at low-voltage terminals 116 a, 116 b (also shown as low-voltage output terminals 116 a, 116 b). The low-voltage terminals 116 a, 116 b output a predetermined low voltage from the voltage converters 108 to the low-voltage bus 120. In this example, each voltage converter 108 has its own low-voltage output terminal 116 a, 116 b, but the voltage converters 108 of the voltage converter network 106 may also be electrically connected to a common low-voltage terminal 116 a of the power supply system 100 that is electrically connectable to a high-voltage side of the low-voltage bus 120. Additionally, the voltage converters 108 of the voltage converter network 106 may also be electrically connected to a common low-voltage terminal 116 b of the power supply system 100 that is electrically connectable to a high-voltage side of the low-voltage bus 120. A structure in which multiple different voltage converters 108 are paralleled as a power source for a predetermined low voltage has high redundancy for supplying a predetermined low voltage to the low voltage bus 120 even if one or more voltage converters 108 fail.

[0040] Optionally, the low-voltage bus 120 may include two low-voltage supply lines electrically connecting different electrical loads to the low-voltage output terminals 116a, 116b. For example, the low-voltage bus 120 may be divided into a first low-voltage bus that supplies a predetermined low voltage to the electrical loads via the first low-voltage supply line and a second low-voltage bus that supplies a predetermined low voltage to the electrical loads via the second low-voltage supply line. The first low-voltage supply line may supply electrical loads that are not critical to the operation of the electric vehicle (or an energy storage system using the power supply system 100), i.e., non-critical loads. The second low-voltage supply line may supply loads that are critical to the operation of the electric vehicle (or an energy storage system using the power supply system 100), i.e., safety-critical loads. Non-critical loads include loads such as an air conditioning system, a heating system, one or more infotainment systems, USB charging points, and an interior lighting system. Safety-critical loads include loads such as a lighting system, airbags, and an ADAS system.

[0041] To ensure the safety of the power supply, optionally, one of the first and second low-voltage supply lines may be electrically connected to a low-voltage battery capable of storing the predetermined low voltage output by the voltage converter network 106. Because the first and second low-voltage buses only need to supply a portion of the total electrical load compared to a conventional power supply system, this low-voltage battery can have a much smaller capacitance and size than the auxiliary battery of a conventional vehicle power supply system.

[0042] Instead of or in addition to distinguishing between critical loads and non-critical loads, the electrical loads supplied by the power supply system 100 may be classified and distinguished according to their power consumption. For example, a first low-voltage bus may supply a predetermined low voltage to electrical loads whose current consumption is equal to or greater than a predetermined threshold, and a second low-voltage bus may supply a predetermined low voltage to electrical loads whose current consumption is less than the predetermined threshold.

[0043] To convert the module voltage to a predetermined low voltage, a DC-DC converter is used as the voltage converter 108. A full-bridge phase-shift converter can be used as an example of an implementation form of each DC-DC converter. Such converters are often used in step-down, isolated, medium- to high-power applications. A full-bridge phase-shift converter uses four electrical switches, such as MOSFET switches or insulated-gate bipolar transistors (IGBTs), to form a full-bridge input, generating a 50% duty cycle in each bridge leg. Power transfer from the input side (primary side) of the full-bridge phase-shift converter to the output side (secondary side) can be controlled by phase-shifting the two signals. A high-frequency transformer can provide isolation between the primary and secondary sides, i.e., galvanic isolation between the high-voltage battery pack 110, which is at least partially electrically connected to the input side of each voltage converter 108, and the low-voltage bus 120, which is connected to the output side of the voltage converter 108 via the low-voltage output terminals 116a and 116b.

[0044] The phase-shift topology of a full-bridge phase-shift converter allows zero-voltage switching of the switches in at least one of the bridge legs of the half-bridge, thereby reducing switching losses and improving power conversion efficiency. The secondary side of a full-bridge phase-shift converter can use active or passive rectification. Active rectification with switches allows for more efficient bidirectional voltage conversion, while passive rectification with diodes reduces cost and design complexity.

[0045] The magnetic transformer is a key component in the full-bridge phase-shift converter design and may consist of a planar transformer integrated into the full-bridge phase-shift converter's printed circuit board. The magnetic components may be integrated into the printed circuit board using traces printed along the layer structure of the printed circuit board to form the magnetic windings. The transformer's magnetic core may be integrated by appropriately slotting the PCB. This design of the voltage converter 108 allows for high-frequency operation while minimizing leakage inductance and AC losses.

[0046] To optimize load management in the voltage converter network 106 , the voltage converter network 106 includes at least one controller that controls the operation of at least one voltage converter 108 .

[0047] If the voltage converter network 106 includes a single voltage converter 108, the controller may be, for example, a microcontroller of the single voltage converter 108 that adjusts the output voltage of the single voltage converter 108 based on the actual output voltage of the single voltage converter 108. For example, the single voltage converter 108 may use different transformation ratios for voltage drops depending on the instantaneous power demand.

[0048] The actual output voltage of the single voltage converter 108 may be measured, for example, by a measurement circuit in the single voltage converter 108. This allows the microcontroller to, for example, ensure that the actual output voltage of the single voltage converter 108 is stepped down depending on the load supplied to the electronic components electrically connected to the low voltage bus 120.

[0049] When the voltage converter network 106 includes multiple voltage converters 108, each voltage converter 108 may include a microcontroller that adjusts the output voltage of the voltage converter 108 based on the actual output voltage of a single voltage converter 108 as a primary control circuit. The actual output voltage of an individual voltage converter 108 can be adjusted, for example, by adapting the voltage transformation ratio of the voltage converter 108. For example, different transformation ratios can be used in the individual voltage converters 108 to provide voltage drops according to instantaneous power demands.

[0050] In this case, the actual output voltage of the voltage converters 108 may be measured, for example, by a measurement circuit in a single voltage converter 108. The actual output voltage of each voltage converter 108 may be measured, for example, by a measurement circuit in each voltage converter 108. This ensures that the actual output voltage of each voltage converter 108 drops in response to the load supplied to the electronic components electrically connected to the low-voltage bus 120. This allows each voltage converter 108 to behave like a virtual resistor, adapting the actual output characteristics of the voltage converter 108 to the load required by the low-voltage bus 120 while distributing the required load among the individual voltage converters 108. Therefore, this technique can achieve a fast transient response to changing load conditions and good power supply stability on the low-voltage bus 120.

[0051] In this case, the voltage converter network 106 further includes a central controller, also denoted as a controller, as a secondary control for controlling the operation of the multiple voltage converters 108. This central controller may be, for example, a microcontroller in a battery management system of the high-voltage battery pack 110, or a dedicated controller provided for the voltage converter network 106 that communicates with a vehicle ECU (engine control unit) that controls the operation of the high-voltage battery pack 110 (e.g., a battery ECU), or may be the vehicle ECU. The central controller is connected to the microcontroller of each voltage converter 108 via communication lines and can activate or deactivate each voltage converter 108 based on the load condition of the low-voltage bus 120. For example, when a large load is supplied by the low-voltage bus 120, the central controller can increase the number of operable voltage converters 108 in the voltage converter network 106, and when a small load is supplied by the low-voltage bus 120, the central controller can reduce the number of active voltage converters 108 in the voltage converter network 106.

[0052] Similarly, the central controller may use each voltage converter 108 to balance the charging of the battery modules 102. In this case, the central controller may activate or deactivate each voltage converter 108 based on the state of charge (SOC) or voltage of the battery module 102 to which the respective voltage converter 108 is electrically connected. For example, if the central controller determines that the SOC or voltage of one of the multiple battery modules 102 is higher than the SOC or voltage of the other battery modules 102, the central controller may activate the voltage converter 108 electrically connected to one battery module 102 and deactivate the other voltage converters 108 in the voltage converter network 106 so that the excess SOC or voltage can be discharged via the low-voltage bus 120. In this manner, the SOC or voltage of the multiple battery modules 102 can be balanced by supplying power to electrical loads electrically connected to the low-voltage bus 120, thereby eliminating the need to waste energy by dissipating energy in balancing resistors.

[0053] In another embodiment, shown in the schematic diagram of FIG. 3, the voltage converters 108 of the voltage converter network 106 may be disposed on a charge monitoring board 122 that includes one or more integrated circuits (cell monitor ICs) for monitoring the charging of one or more of the battery modules 102(1)-102(N) to which the charge monitoring board 122 is attached. The charge monitoring board 122 may be implemented as a printed circuit board that includes one or more cell monitor ICs and other peripheral circuits, such as a communication interface that enables communication between each cell monitor IC and an external controller (e.g., a main control circuit of a battery management system). As shown in FIG. 3, preferably, one charge monitoring board 122(1), 122(2), ..., 122(N) is attached to each of the battery modules 102(1), 102(2), ..., 102(N).

[0054] That is, according to this aspect of the present disclosure, charging monitor boards 122 are disclosed that include integrated voltage converters 108 that convert the module voltage of the battery module 102 to which each charging monitor board 122 is attached to a predetermined low voltage. Each charging monitor board 122 can function as a power source for the low-voltage bus 120 electrically connected to the low-voltage terminals 116a, 116b. This allows the voltage converters 108 to share communication lines provided in the charging monitor boards 122 on which they are located when communicating with, for example, a central controller of the voltage converter network 106. Therefore, each charging monitor board with an integrated voltage converter can achieve the effects of the present disclosure described above, and can minimize costs and design man-hours through a highly integrated design.

[0055] According to another aspect of the present disclosure, the voltage converter network 106 generates an excitation signal for performing electrochemical impedance spectroscopy (also referred to as EIS) of at least one of the plurality of battery modules 102 or the entire high-voltage battery 110.

[0056] Electrochemical impedance spectroscopy (EIS) is based on a safe perturbation technique and can be used to model the electrochemical processes within the high-voltage battery pack 110 or a subunit of the high-voltage battery pack 110, such as a predetermined number of battery modules 102. This is done by exciting the high-voltage battery pack 110 or a portion of the battery modules 102 with excitation currents having different frequencies and determining the impedance response of the high-voltage battery 110 or a portion of the battery modules 102. Because an increase in impedance is directly proportional to the decrease in capacitance of the high-voltage battery pack 110 or a portion of the battery modules 102 due to aging, degradation of the high-voltage battery 110 or a portion of the battery modules 102 can be determined. Therefore, the state of health (SOH) of the high-voltage battery pack 110 can be determined by analyzing the impedance response as a function of frequency using EIS.

[0057] Performing online EIS in the power supply system 100 enables monitoring of the SOH of the high-voltage battery pack 110 throughout the life of the electric vehicle. Conventional power supply systems require additional hardware to generate a current excitation signal as a perturbation signal. Furthermore, using existing electrical components to measure the CMB voltage requires a high excitation current to measure the resulting voltage perturbation with sufficient accuracy. Online EIS techniques typically use a switched resistive load to generate the current excitation signal. Typically, a sinusoidal modulation signal, generated using pulse-width modulation, for example, is applied to the switch. By varying the frequency of the modulation signal, the impedance response can be measured as a function of frequency. However, conventional techniques suffer from large current ripple and require significant data processing efforts to remove high-frequency noise resulting from the switching current component.

[0058] This drawback can be remedied by using a specific configuration of the power supply system 100. In particular, the power supply system 100 includes a voltage converter network 106 of voltage converters 108 that act as a parallel power source for the low-voltage bus 120. However, each voltage converter 108 can also be used to generate a current excitation signal that performs EIS for one or more battery modules 102, or for the entire high-voltage battery pack 110.

[0059] By using the voltage converter 108 to generate the current excitation signal, the reactive components of the voltage converter 108 can generate a sinusoidal current with low total harmonic distortion (THD) as the excitation signal (or perturbation signal). This reduces the data processing burden for determining the impedance response and improves the overall accuracy of the impedance measurement. Furthermore, using the existing voltage converter 108 eliminates the need for extra hardware, and the energy used during EIS is dissipated in an electrical load electrically connected to the low-voltage bus 120, rather than in a resistor. [Explanation of symbols]

[0060] 10 Auxiliary Battery 20 DC / DC voltage converter 30 High Voltage Bus 40 High Voltage Battery 50a, 50b contactors 60 Low Voltage Bus 100 Power System 102 Battery Module 104 Connecting Nodes 106 Voltage Converter Network 108 Voltage Converter 110 High Voltage Battery Pack 112 High Voltage Bus 114a, 114b contactors 116a, 116b Low voltage terminals 120 Low Voltage Bus 122 Charging monitoring board

Claims

1. a high-voltage battery pack (110) including a plurality of battery modules (102) electrically connected in series to form the high-voltage battery pack (110), the high-voltage battery pack (110) being configured to output a predetermined high voltage as a sum of module voltages supplied by the plurality of battery modules (102); low-voltage output terminals (116a, 116b) configured to output a predetermined low voltage to at least one electrical load; a voltage converter network (106) configured to electrically isolate the low voltage output terminals (116a, 116b) from the high voltage battery pack (110) and to convert at least a portion of the module voltage to the predetermined low voltage; The voltage converter network (106) a plurality of voltage converters (108), each electrically connected to at least one of the plurality of battery modules (102), configured to convert the module voltage supplied by the at least one of the plurality of battery modules (102) to the predetermined low voltage, and output the predetermined low voltage as an output voltage to the low-voltage output terminals (116 a, 116 b); a controller configured to control the operation of the plurality of voltage converters (108) and to activate or deactivate each of the plurality of voltage converters (108); Each of the plurality of voltage converters (108) comprises a measurement circuit configured to measure an actual output voltage of the voltage converter (108); and a microcontroller configured to adapt a voltage conversion ratio of the voltage converter (108) based on the actual output voltage measured by the measurement circuit, and to convert a module voltage supplied by at least one battery module (102) to which the voltage converter (108) is electrically connected in accordance with an instantaneous power demand; the controller is configured to activate or deactivate each of the plurality of voltage converters (108) to increase or decrease, respectively, the number of voltage converters (108) operating within the voltage converter network (106) based on the total load electrically connected to the low-voltage output terminals (116a, 116b); A power supply system (100).

2. The plurality of voltage converters (108) are connected in parallel with one another within the voltage converter network (106). The power system (100) of claim 1.

3. The plurality of voltage converters (108) are each electrically connected to an equal number of battery modules (102). The power supply system (100) of claim 1 or 2.

4. The number of the same number of battery modules (102) is 1. The power supply system (100) of claim 3.

5. each of the plurality of voltage converters (108) comprising a communication circuit configured to communicate a measured actual output voltage to the controller of the voltage converter network (106); The power system (100) of claim 1.

6. the controller is configured to activate or deactivate each of the plurality of voltage converters (108) based on a state of charge of at least one battery module (102) to which each of the voltage converters (108) is electrically connected. The power system (100) of claim 1.

7. The plurality of voltage converters (108) are each mounted on a printed circuit board (122) provided as part of a battery management system for the high-voltage battery pack (110). The power system (100) of claim 1.

8. the voltage converter network (106) is configured to generate an excitation signal for electrochemical impedance spectroscopy of at least one of the plurality of battery modules (102); The power system (100) of claim 1.

9. a low-voltage bus (120) configured to electrically connect the low-voltage output terminals (116a, 116b) to the at least one electrical load; The power system (100) of claim 1.

10. the low-voltage bus (120) comprises a first low-voltage supply line and a second low-voltage supply line, the first low-voltage supply line and the second low-voltage supply line supplying different classes of electrical loads; The power supply system (100) of claim 9.

11. The module voltage is in the range of 30V to 60V; The power system (100) of claim 1.

12. The high-voltage battery pack (110) is a traction battery configured to supply power to a motor of an electric vehicle. The power supply system of claim 1 .

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