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 capable of outputting a predetermined high voltage to an electric load such as an electric motor of an electric vehicle, and outputting 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. Typically, high-voltage battery packs used in electric vehicles consist of 80 to 300 battery cells connected in series and are used to power the high-voltage system of the electric vehicle, 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 supplying a low voltage of 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, the 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. Between the terminals of the high-voltage battery 40 and the DCDC voltage converter 20, contactors 50a, 50b are arranged that can be opened to cut off the power supply of the high-voltage bus 30, for example, when the electric vehicle is turned off or when a high-voltage short circuit occurs. Thus, the auxiliary battery 10 not only balances the load and demand of the low-voltage bus 60 electrically connected to the auxiliary battery 10, but also functions as an energy reservoir for the electric loads connected to the low-voltage bus 60 when the electric vehicle is turned off. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inventors of the present invention have found that the high input voltage supplied by the high voltage battery pack and the high output current supplied by the low voltage bus place high stress on the components of the DC-DC converter, which are prone to significant degradation. Furthermore, the typical auxiliary battery used in conventional systems is expensive, heavy, and requires a large amount of space in a safe 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 as defined in the independent claims.

[0008] In particular, according to an aspect 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 provided 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 a module voltage provided 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 part 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 does not require energy storage in an auxiliary battery connected to the low-voltage bus of the electric vehicle, since power can 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. 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, whereby the voltage converters can act as independent low-voltage power sources for electrical loads electrically connected to the low-voltage terminals of the power supply system. This parallel structure allows operation of the power supply system even in the event of a failure in one or more of the voltage converters. In this way, a continuous power supply to safety-critical electrical loads electrically connected to the low-voltage terminals can be ensured.

[0014] In another advantageous aspect of the present disclosure, the multiple voltage converters are electrically connected to the same number of battery modules, respectively. 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 at least one voltage converter, respectively. Thus, the controller may preferably be configured to activate or deactivate at least one voltage converter, respectively, based on the overall load electrically connected to the low-voltage output terminal and / or based on the state of charge of at least one battery module to which the respective 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 terminal and supplied by the voltage converter network. Furthermore, this configuration allows balancing of module voltages of battery modules at the module level without dissipating energy through the use of balancing resistors.

[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 allows the use of communication lines provided in each CMB for communication between the multiple voltage converters and a controller of the voltage converters.

[0019] In another advantageous aspect of the present disclosure, the voltage converter network is configured to generate an excitation signal for electrochemical impedance spectroscopy of at least one of the battery modules. The current generated for EIS electrochemical impedance spectroscopy (EIS) can be directly consumed by an electrical load electrically connected to the low voltage output terminal and supplied by the voltage converter network, thereby avoiding the power loss of the switch resistance used in conventional EIS. Furthermore, the reactive electrical components inside each voltage converter can generate a current sine wave with a lower total harmonic distortion (THD) compared to the excitation signal generated in a conventional manner, thereby reducing the data processing load for analyzing the results of the impedance measurement and increasing 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] In order to optimize the reduction of the required voltage conversion ratio of at least one voltage converter of the voltage converter network and the voltage stress applied to the input semiconductors of the at least one voltage converter, the module voltage provided by each battery module is in the range of 30 V to 60 V. That is to say, the high-voltage battery pack is divided into units of battery modules, each providing 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 a particular advantageous aspect of the present disclosure, the high voltage battery pack is a traction battery configured to power a motor of an electric vehicle, and for such an application, a low voltage auxiliary battery conventionally 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 200V, preferably in the range of 400V to 1000V, and the term "low voltage" refers to a voltage in the range of 0V to 100V, preferably in the range of 0V to 50V.

[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 refer to the entire wire that conductively couples 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 indicated with the same reference numerals, and in which: [Brief description of the drawings]

[0027] The accompanying drawings are incorporated herein and form a part of the 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 on how to implement and use the present invention, and should not be construed as limiting the present 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 mentioned above can be provided independently of each other or can be omitted entirely during the implementation of the present invention. Further features and advantages will become apparent from the following more specific description of the various aspects, as illustrated in the accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of a prior art power supply system. [Diagram 2] FIG. 2 is a schematic diagram of a power supply system according to one embodiment of the present disclosure. [Diagram 3] FIG. 3 is another schematic diagram of a power supply system according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0029] The power supply system 100 is provided with a high-voltage battery pack 110 (sometimes referred to herein as a high-voltage battery 110), which 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-potential terminal and a low-potential terminal of the battery pack 110 and can supply the predetermined high voltage to an electric motor of a vehicle. The contactors 114a and 114b are disposed on the high-voltage bus 112. In this example, the contactor 114a may be electrically connected to a high-potential terminal of the high-voltage battery pack 110, and the contactor 114b may be electrically connected to a low-potential terminal of the high-voltage battery pack 110. By opening and closing the contactors 114a and 114b, the supply of power from the high-voltage battery pack 110 to the electric motor via the high-voltage bus 112 can be interrupted.

[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 to the upper high potential side of the high-voltage battery pack 110 for ease of distinction.

[0031] The multiple battery modules 102 are subunits of the high-voltage battery pack 110, and supply a module voltage that, in total, is 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 comprises a number of battery cells electrically connected in series. The battery cells may be physical battery cells or may comprise a number of physical battery cells electrically connected in parallel at the cell level. As an example, 12 to 14 battery cells, each having a cell voltage of 3.3V to 4.3V, may be electrically connected in series to form each battery module 102. Thus, in this example, each battery module 102 may provide a module voltage of 30V to 60V. However, other predetermined numbers of battery cells with other predetermined cell voltages may be electrically connected to form the battery module 102 to provide a smaller or larger module voltage.

[0033] To supply a predetermined low voltage to some electric loads in addition to the predetermined high voltage supplied to the electric motor of the vehicle, the power supply system 100 comprises a voltage converter network 106. The voltage converter network 106 is configured to convert at least a part of the module voltage supplied by the battery module 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 configured to supply the electric loads at the predetermined low voltage.

[0034] The voltage converter network 106 includes voltage converters 108. In order to distinguish each of the M voltage converters 108, in Fig. 2, the M voltage converters 108 are denoted 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.

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

[0036] However, the total number M of the voltage converters 108 in the voltage converter network 106 does not necessarily have to be equal to the total number N of the 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 to convert an input voltage as a sum of a portion of the module voltages. Here, it is preferable that each voltage converter 106 is electrically connected to the same number of battery modules 102 to equalize the input voltages of the voltage converters 108. This can simplify the control of the voltage converters 108, which 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 the low-voltage bus 120 electrically connected to the voltage converter network 106 at low-voltage terminals 116a, 116b (also shown as low-voltage output terminals 116a, 116b). The low-voltage terminals 116a, 116b 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 116a, 116b, but the voltage converters 108 of the voltage converter network 106 may be electrically connected to a common low-voltage terminal 116a of the power supply system 100 that is electrically connectable to the high-potential side of the low-voltage bus 120. Additionally, the voltage converters 108 of the voltage converter network 106 may be electrically connected to a common low-voltage terminal 116b of the power supply system 100 that is electrically connectable to the high-potential side of the low-voltage bus 120. The structure in which multiple different voltage converters 108 are paralleled as a power source of a predetermined low voltage has a high degree of 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 comprise two low-voltage supply lines electrically connecting different electrical loads to the low-voltage output terminals 116a, 116b. Thus, for example, the low-voltage bus 120 may be divided into a first low-voltage bus supplying a predetermined low voltage to the electrical loads via the first low-voltage supply line and a second low-voltage bus supplying a predetermined low voltage to the electrical loads via the second low-voltage supply line. The first low-voltage supply line may, for example, supply electrical loads that are not critical to the operation of the electric vehicle (or the energy storage system using the power supply system 100), i.e. non-critical loads. The second low-voltage supply line may, for example, supply loads that are critical to the operation of the electric vehicle (or the energy storage system using the power supply system 100), i.e. safety-critical loads. Non-critical loads include, for example, loads such as an air conditioning system, a heating system, one or more infotainment systems, USB charging points, an interior lighting system, etc. Safety-critical loads include, for example, loads such as a lighting system, airbags, ADAS systems, etc.

[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 a predetermined low voltage output by the voltage converter network 106. Since 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 be of much smaller capacitance and size than the auxiliary battery of a conventional vehicle power supply system.

[0042] Alternatively or in addition to distinguishing between critical and non-critical loads, the electrical loads supplied by the power supply system 100 may be classified and differentiated 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. As an example of an implementation form of each DC-DC converter, a full-bridge phase-shift converter can be used. Such converters are often used in step-down, isolated, and medium to high power applications. The 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 and generate a 50% duty cycle in each bridge leg. The power transfer from the input side (primary side) to the output side (secondary side) of the full-bridge phase-shift converter can be controlled by phase-shifting two signals. A high-frequency transformer can provide isolation between the primary side and the secondary side, 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, 116b.

[0044] The phase-shift topology design of the full-bridge phase-shift converter allows zero-voltage switching on the switches of at least one bridge leg of the half-bridge, which reduces switching losses and improves power conversion efficiency. The secondary side of the full-bridge phase-shift converter can use active or passive rectification. Active rectification with switches allows bidirectional voltage conversion with higher efficiency, while passive rectification using 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 printed circuit board of the full-bridge phase-shift converter. 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 magnetic core of the transformer may be integrated by appropriately slotting the PCB. Such a design of the voltage converter 108 allows high frequency operation with minimal 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 of the single voltage converter 108. This allows the microcontroller, for example, to ensure that the actual output voltage of the single voltage converter 108 is stepped down in response to the load supplied to the electronic components electrically connected to the low voltage bus 120.

[0049] When the voltage converter network 106 comprises multiple voltage converters 108, each voltage converter 108 may comprise 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] Also, in this case, the actual output voltage of the voltage converter 108 may be measured, for example, by a measurement circuit of a single voltage converter 108. The actual output voltage of each voltage converter 108 may be measured, for example, by a measurement circuit of each voltage converter 108. This ensures that the actual output voltage of each voltage converter 108 is dropped according to the load supplied to the electronic components electrically connected to the low-voltage bus 120. This allows the individual voltage converters 108 to behave like virtual resistors, and the actual output characteristics of the voltage converters 108 can be adapted to the load required by the low-voltage bus 120 while distributing the required load to the individual voltage converters 108. Thus, the present technique can achieve a fast transient response to changes in load conditions and good stability of the power supply on the low-voltage bus 120.

[0051] In this case, the voltage converter network 106 further comprises a central controller, also indicated as a controller for controlling the operation of the multiple voltage converters 108, as a secondary control. This central controller may be, for example, a microcontroller of the battery management system of the high-voltage battery pack 110, or may be 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., battery ECU), or may be the vehicle ECU. The central controller is connected to the microcontrollers of each voltage converter 108 via communication lines and can control each voltage converter 108 to be activated or deactivated 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 decrease 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 control the activation or deactivation of 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 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 of 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 battery modules 102 may be balanced by supplying power to an electrical load electrically connected to the low-voltage bus 120, without the need to waste energy by dissipating the load in a balancing resistor.

[0053] In another embodiment, shown in the schematic diagram of FIG. 3, the voltage converters 108 of the voltage converter network 106 may be arranged 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 provided as a printed circuit board provided with one or more cell monitor ICs and other peripheral circuits such as a communication interface that allows 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, it is preferable that 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, a charging monitoring board 122 is disclosed that includes an integrated voltage converter 108 that converts the module voltage of the battery module 102 to which the charging monitoring board 122 is attached to a predetermined low voltage. Each charging monitoring 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 the communication lines provided in the charging monitoring board 122 in which they are located when communicating with, for example, a central controller of the voltage converter network 106. Thus, each charging monitoring board incorporating a voltage converter can achieve the effects of the present disclosure described above, and can minimize costs and design man-hours with a highly integrated design.

[0055] According to another aspect of the 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 model electrochemical processes inside the high voltage battery pack 110 or a subunit of the high voltage battery pack 110, such as a number of battery modules 102. This is done by exciting the high voltage battery pack 110 or a portion of the battery module 102 with excitation currents having different frequencies and determining the impedance response of the high voltage battery 110 or the portion of the battery module 102. Since the increase in impedance is directly proportional to the decrease in capacitance of the high voltage battery pack 110 or the portion of the battery module 102 due to aging, the degradation of the high voltage battery 110 or the portion of the battery module 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] By performing online EIS in the power supply system 100, it becomes possible to monitor the SOH of the high voltage battery pack 110 during the service life of the electric vehicle. In conventional power supply systems, additional hardware is required to generate a current excitation signal as a perturbation signal. Furthermore, if existing electrical components are used for voltage measurement of the CMB, a high excitation current is required to measure the resulting voltage perturbation with sufficient accuracy. Generally, the online EIS method uses a switched resistive load to generate the current excitation signal. Typically, a sinusoidal modulated signal, generated for example using pulse width modulation, is applied to the switch. By varying the frequency of the modulated signal, the impedance response can be measured as a function of frequency. However, the conventional technique has a large current ripple and requires a lot of effort in data processing to remove high frequency noise resulting from the switching current component.

[0058] This drawback can be remedied by using a particular 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 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). Thus, the burden of data processing to determine the impedance response can be reduced, and the overall accuracy of the impedance measurement can be improved. Furthermore, since the existing voltage converter 108 is used, no extra hardware is required, and the energy used during EIS is dissipated in an electrical load electrically connected to the low voltage bus 120, rather than being dissipated 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 Contactor 116a, 116b Low voltage terminals 120 Low Voltage Bus 122 Charging monitoring board

Claims

1. a high-voltage battery pack (110) comprising 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 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; 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) comprises: at least one voltage converter (108), 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 (116a, 116b); a controller configured to control operation of the at least one voltage converter. A power supply system (100).

2. The voltage converter network (106) comprises a plurality of voltage converters (108); each of the plurality of voltage converters (108) is electrically connected to at least one of the plurality of battery modules (102), and is configured to convert the module voltage supplied by at least one of the plurality of battery modules (102) to the predetermined low voltage, and to output the predetermined low voltage as an output voltage to the low voltage output terminals (116a, 116b); The power system (100) of claim 1.

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

4. 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 2 or 3.

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

6. Each of the at least one voltage converters (108) comprises a measurement circuit configured to measure an actual output voltage of the voltage converter (108) and a microcontroller configured to adjust the output voltage of the voltage converter (108) based on the measured actual output voltage. A power supply system (100) according to any one of the preceding claims.

7. each of the at least one voltage converters (108) includes a communication circuit configured to communicate a measured actual output voltage to the controller of the voltage converter network (106); A power supply system (100) according to any one of the preceding claims.

8. The controller is configured to control each of the at least one voltage converter (108) to be active or inactive. A power supply system (100) according to any one of the preceding claims.

9. the controller is configured to control the activation or deactivation of each of the at least one voltage converter (108) based on an overall load electrically connected to the low-voltage output terminals (116a, 116b) and / or 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 8.

10. each of the at least one voltage converters (108) is provided on a printed circuit board (122) provided as part of a battery management system for the high voltage battery pack (110); A power supply system (100) according to any one of the preceding claims.

11. 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); A power supply system (100) according to any one of the preceding claims.

12. a low-voltage bus (120) configured to electrically connect the low-voltage output terminals (116a, 116b) to the at least one electrical load. A power supply system (100) according to any one of the preceding claims.

13. 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 optionally supplying different classes of electrical loads; The power system (100) of claim 12.

14. The module voltage is in the range of 30V to 60V; A power supply system (100) according to any one of the preceding claims.

15. The high-voltage battery pack (110) is a traction battery configured to supply power to a motor of an electric vehicle. A power supply system according to any one of claims 1 to 14.

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