Distributed low voltage power generation architecture for battery electrified aircraft

Abstract

The power distribution system, the battery pack, and the battery employ battery modules connected in series to generate a high voltage output and connected in parallel to generate a low voltage output. The battery includes a battery module and a DC-to-DC converter. The battery modules are electrically connected in series to generate a first battery high voltage output. The battery modules are electrically connected in parallel to generate a battery module low voltage output. A DC-to-DC converter generates a battery low voltage output from the battery module low voltage output.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 430,313, filed on December 5, 2022, the disclosure of which is incorporated herein by reference. Background of the Invention

[0003] Aircraft typically include a variety of power - driven systems and devices, such as propulsion systems, avionics, control surfaces, lights, high - lift devices, and passenger systems and devices. These power - driven systems and devices typically have different power requirements. In battery - electrified aircraft, the different power requirements may result in using different voltages to supply power to the power - driven systems and devices. For example, a relatively high voltage may be used to supply power to high - power - consumption systems such as propulsion systems (e.g., lift / thrust fan units). A relatively low voltage may be used to supply power to low - power - consumption systems such as avionics, control surfaces, lights, and passenger systems and devices. However, the use of both high and low voltages in battery - electrified aircraft presents challenges for meeting aircraft design requirements such as safety, weight, aircraft production cost, and aircraft operating cost. Summary of the Invention

[0004] A simplified overview of some embodiments of the present invention is presented below to provide a basic understanding of the present invention. This overview is not an extensive summary of the present invention. It is not intended to identify key / critical elements of the present invention or to delineate the scope of the present invention. Its sole purpose is to present some embodiments of the present invention in a simplified form as a prelude to the more detailed description that follows.

[0005] A power distribution system, a battery pack, and a battery are presented that supply both high-voltage power and low-voltage power. In one example, an aircraft power distribution system is configured to supply high-voltage power to a propulsion load and low-voltage power to a system load. The aircraft power distribution system includes batteries, where each of the batteries includes battery modules. The battery modules are electrically connected in series to generate a high-voltage output. The battery modules are also electrically connected in parallel to generate a low-voltage output. The parallel connection between the battery modules can employ a passive current flow control component (such as a diode) to preferentially discharge the battery module with a higher state of charge based on the voltage of the battery module, thereby distributing the contribution to the low-voltage output among the battery modules. The battery can include a DC-to-DC converter to generate the low-voltage output of the battery from the combined output of the battery modules. The DC-to-DC converter can be configured to implement a voltage drop in the low-voltage output of the battery to provide passive balancing with the (one or more) low-voltage outputs of one or more other batteries to preferentially discharge the battery with a higher state of charge. The outputs from two or more batteries can be combined to provide fail-safe redundancy for power supply from two or more batteries in the event of a failure in one of the two or more batteries.

[0006] Thus, in one aspect, an aircraft power distribution system for supplying power to a high-voltage propulsion load and a low-voltage system load includes a battery pack, a first power distribution unit, and a second power distribution unit. The battery pack includes a first battery and a second battery. The first battery includes a first battery module and a first DC-to-DC converter. The second battery includes a second battery module and a second DC-to-DC converter. The first battery module is electrically connected in series to generate a first battery high-voltage output. The second battery module is electrically connected in series to generate a second battery high-voltage output. The first battery high-voltage output and the second battery high-voltage output are used to supply power to a group of high-voltage propulsion loads. The first battery module is electrically connected in parallel to generate a first battery module low-voltage output. The first DC-to-DC converter generates a first battery low-voltage output from the first battery module low-voltage output. The second battery module is electrically connected in parallel to generate a second battery module low-voltage output. The second DC-to-DC converter generates a second battery low-voltage output from the second battery module low-voltage output. The first power distribution unit distributes the first battery low-voltage output to a first group of low-voltage system loads. The second power distribution unit distributes the second battery low-voltage output to a second group of low-voltage system loads.

[0007] Each of the first battery and the second battery can include any suitable number of battery modules. For example, the first battery can include two, three, four, five, six, or more first battery modules. Similarly, the second battery can include two, three, four, five, six, or more second battery modules.

[0008] The high-voltage output of the first battery and the high-voltage output of the second battery can be combined in any suitable manner. For example, the high-voltage output of the first battery and the high-voltage output of the second battery can be electrically connected in parallel to generate a high-voltage output of the battery pack, which is supplied to the group of high-voltage propulsion loads. In another example, the high-voltage output of the first battery and the high-voltage output of the second battery can be electrically connected in series to generate a high-voltage output of the battery pack, which is supplied to the group of high-voltage propulsion loads.

[0009] Current flow control components such as diodes can be employed to passively control the discharge of the battery modules to preferentially discharge the battery modules with a higher state of charge. For example, the first battery can include a first current flow control component (e.g., a diode) connected between the low-voltage output of the first battery module and the first battery module to block current from flowing from the low-voltage output of the first battery module to the first battery module and to allocate the contribution of the first battery module to the low-voltage output of the first battery module based on the output voltage of the first battery module. The second battery can include a second current flow control component (e.g., a diode) connected between the low-voltage output of the second battery module and the second battery module to block current from flowing from the low-voltage output of the second battery module to the second battery module and to allocate the contribution of the second battery module to the low-voltage output of the second battery module based on the output voltage of the second battery module.

[0010] Each of the first battery and the second battery can incorporate a voltage drop into its respective low-voltage output to provide passive balancing of the discharge of the first battery and the second battery. For example, a first DC-DC converter can be configured to generate a first battery low-voltage output from the low-voltage output of the first battery module to create a first voltage drop in the first battery low-voltage output. A second DC-DC converter can be configured to generate a second battery low-voltage output from the low-voltage output of the second battery module to create a second voltage drop in the second battery low-voltage output.

[0011] The aircraft power distribution system may further include a second battery pack, a third power distribution unit, and a fourth power distribution unit. The second battery pack may include a third battery and a fourth battery. The third battery may include a third battery module and a third DC-DC converter. The fourth battery may include a fourth battery module and a fourth DC-DC converter. The third battery modules may be electrically connected in series to generate a third battery high-voltage output. The fourth battery modules may be electrically connected in series to generate a fourth battery high-voltage output. The third battery high-voltage output and the fourth battery high-voltage output may be used to power a second group of high-voltage propulsion loads. The third battery modules may be electrically connected in parallel to generate a third battery module low-voltage output. The third DC-DC converter may be configured to generate a third battery low-voltage output from the third battery module low-voltage output. The fourth battery modules may be electrically connected in parallel to generate a fourth battery module low-voltage output. The fourth DC-DC converter may be configured to generate a fourth battery low-voltage output from the fourth battery module low-voltage output. The third power distribution unit may be configured to distribute the third battery low-voltage output to a third group of low-voltage system loads. The fourth power distribution unit may be configured to distribute the fourth battery low-voltage output to a fourth group of low-voltage system loads.

[0012] The aircraft power distribution system may be configured to provide power distribution redundancy. For example, the first power distribution unit, the second power distribution unit, the third power distribution unit, and the fourth power distribution unit may be electrically connected to the low-voltage system loads such that each of the low-voltage system loads is powered by at least two of the first power distribution unit, the second power distribution unit, the third power distribution unit, and the fourth power distribution unit.

[0013] Each of the third battery and the fourth battery may include any suitable number of battery modules. For example, the third battery may include two, three, four, five, six, or more third battery modules. Similarly, the fourth battery may include two, three, four, five, six, or more fourth battery modules.

[0014] The third battery high-voltage output and the fourth battery high-voltage output may be combined in any suitable manner. For example, the third battery high-voltage output and the fourth battery high-voltage output may be electrically connected in parallel to generate a second battery pack high-voltage output, which is supplied to the second group of high-voltage propulsion loads. In another example, the third battery high-voltage output and the fourth battery high-voltage output may be electrically connected in series to generate a second battery pack high-voltage output, which is supplied to the second group of high-voltage propulsion loads.

[0015] A current flow control component such as a diode can be employed to passively control the discharge of the third battery module and the fourth battery module to preferentially discharge the battery module with a higher state of charge. For example, the third battery may include a third current flow control component (e.g., a diode) connected between the low-voltage output of the third battery module and the third battery module to block current from flowing from the low-voltage output of the third battery module to the third battery module and distribute the contribution of the third battery module to the low-voltage output of the third battery module based on the output voltage of the third battery module. The fourth battery may include a fourth current flow control component (e.g., a diode) connected between the low-voltage output of the fourth battery module and the fourth battery module to block current from flowing from the low-voltage output of the fourth battery module to the fourth battery module and distribute the contribution of the fourth battery module to the low-voltage output of the fourth battery module based on the output voltage of the fourth battery module.

[0016] Each of the third battery and the fourth battery can incorporate a voltage drop into its respective low-voltage output to provide passive balancing of the discharges of the third battery and the fourth battery. For example, the third DC-DC converter can be configured to generate a third battery low-voltage output from the low-voltage output of the third battery module to create a third voltage drop in the third battery low-voltage output. The fourth DC-DC converter can be configured to generate a fourth battery low-voltage output from the low-voltage output of the fourth battery module to create a fourth voltage drop in the fourth battery low-voltage output.

[0017] In another aspect, the battery pack includes a first battery and a second battery. The first battery includes a first battery module and a first DC-DC converter. The first battery module is electrically connected in series to generate a first battery high-voltage output. The first battery module is electrically connected in parallel to generate a first battery module low-voltage output. The first DC-DC converter is configured to generate a first battery low-voltage output from the low-voltage output of the first battery module. The second battery includes a second battery module and a second DC-DC converter. The second battery module is electrically connected in series to generate a second battery high-voltage output. The second battery module is electrically connected in parallel to generate a second battery module low-voltage output. The second DC-DC converter is configured to generate a second battery low-voltage output from the low-voltage output of the second battery module.

[0018] Each of the first battery and the second battery in the battery pack can include any suitable number of battery modules. For example, the first battery can include two, three, four, five, six, or more first battery modules. Similarly, the second battery can include two, three, four, five, six, or more second battery modules.

[0019] The high-voltage outputs of the first battery and the second battery in the battery pack can be combined in any suitable manner. For example, the high-voltage outputs of the first battery and the second battery can be electrically connected in parallel to generate the high-voltage output of the battery pack. In another example, the high-voltage outputs of the first battery and the second battery can be electrically connected in series to generate the high-voltage output of the battery pack.

[0020] Current flow control components such as diodes can be employed in the battery pack to passively control the discharge of the battery modules to preferentially discharge the battery modules with a higher state of charge. For example, the first battery can include a first current flow control component (such as a diode) connected between the low-voltage output of the first battery module and the first battery module to block current from flowing from the low-voltage output of the first battery module to the first battery module and distribute the contribution of the first battery module to the low-voltage output of the first battery module based on the output voltage of the first battery module. The second battery can include a second current flow control component (such as a diode) connected between the low-voltage output of the second battery module and the second battery module to block current from flowing from the low-voltage output of the second battery module to the second battery module and distribute the contribution of the second battery module to the low-voltage output of the second battery module based on the output voltage of the second battery module.

[0021] Each of the first battery and the second battery in the battery pack can incorporate a voltage drop into their respective low-voltage outputs to provide passive balancing of the discharges of the first battery and the second battery. For example, a first DC-to-DC converter can be configured to generate a first battery low-voltage output from the low-voltage output of the first battery module to create a first voltage drop in the first battery low-voltage output. A second DC-to-DC converter can be configured to generate a second battery low-voltage output from the low-voltage output of the second battery module to create a second voltage drop in the second battery low-voltage output.

[0022] On the other hand, the battery includes a battery module and a DC-to-DC converter. The battery modules are electrically connected in series to generate a first battery high-voltage output. The battery modules are electrically connected in parallel to generate a battery module low-voltage output. The DC-to-DC converter is configured to generate a battery low-voltage output from the battery module low-voltage output.

[0023] The battery can include any suitable number of battery modules. For example, the battery can include two, three, four, five, six, or more battery modules.

[0024] The battery may include a current flow control component such as a diode to passively control the discharge of the battery module to preferentially discharge the battery module with a higher state of charge. For example, the battery may include a current flow control component (e.g., a diode) connected between the low voltage output of the battery module and the battery module to block current from flowing from the low voltage output of the battery module to the battery module and to allocate the contribution of the battery module to the low voltage output of the battery module based on the output voltage of the battery module.

[0025] The battery may incorporate a voltage drop into the battery low voltage output to provide passive balancing of the discharge of the battery and one or more other batteries. For example, a DC-to-DC converter may be configured to generate the battery low voltage output from the low voltage output of the battery module to create a voltage drop in the battery low voltage output.

[0026] To more fully understand the nature and advantages of the present invention, reference should be made to the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 An electric aerial vehicle including a power distribution system according to an embodiment is depicted.

[0028] Figure 2 Schematically illustrates Figure 1 the low voltage distribution aspect of the power distribution system of

[0029] Figure 3 Schematically illustrates Figure 1 the battery pack of the power distribution system of

[0030] Figure 4 Shows an example voltage drop relationship that can be achieved by the DC-to-DC converter of the battery pack of Figure 3

[0031] Figure 5 Shows a graph illustrating Figure 3 an example variation of the battery module output voltage with the state of charge of the battery module in the battery pack of

[0032] Figure 6 Shows a graph illustrating Figure 1 an example variation of the battery module output voltage with flight duration in the power distribution system of DETAILED DESCRIPTION

[0033] In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to those skilled in the art that the present invention may be practiced without specific details. Furthermore, well-known features may be omitted or simplified so as not to obscure the described embodiments.​

[0034] A power distribution system, a battery pack, and a battery that supply both high-voltage power and low-voltage power are presented. In the illustrated embodiment, the aircraft power distribution system is configured to supply high-voltage power to a propulsion load and low-voltage power to a system load. The aircraft power distribution system employs batteries including battery modules that are electrically connected in series to generate a high-voltage output used to power the high-voltage propulsion load, and the battery modules are electrically connected in parallel to generate a low-voltage output used to power the low-voltage system load. The aircraft power distribution system employs redundant power distribution to provide fail-safe power distribution in the event of one or more failures (such as battery failures, short circuits) in the aircraft power distribution system. The aircraft power distribution system employs load balancing such that battery modules with a higher state of charge discharge prior to battery modules with a lower state of charge. The aircraft power distribution system includes a battery pack. Each of the battery packs in the illustrated embodiment includes two batteries. Although the battery packs and batteries are described herein as components of the illustrated aircraft distribution system, any suitable number of battery packs (e.g., one, two, three, or more) can be employed in any suitable application to store and supply power. Similarly, any suitable number of batteries (e.g., one, two, three, or more) can be employed in any suitable application to store and supply power.

[0035] Turning now to the drawings, where like reference identifiers are used to designate like elements in the various figures, Figure 1 An electric aerial vehicle 100 including a power distribution system 102 is depicted according to an embodiment. As Figure 1 shown, the aerial vehicle 100 includes twelve motors 105a - 105l. The power distribution system 102 includes six battery packs 110a, 110b, 110c, 110d, 110e, 110f and a high-voltage distribution subsystem 115, and the twelve motors 105a - 105l are coupled to the battery packs 110a - f via the high-voltage distribution subsystem 115. In many embodiments, each of the twelve motors 105a - 105l is used to drive a propulsion fan 112 (e.g., a tiltable lift / propulsion fan) and is configured to operate at a relatively high supply voltage (e.g., up to 792V), which is supplied by the battery packs 110a - f. The high-voltage subsystem 115 can have any suitable configuration for operably coupling each of the motors 105a - 105l to the battery packs 110a - f to meet airworthiness requirements.

[0036] In addition to motors 105a - 105l, the aerial vehicle 100 also includes a low - voltage system that is also powered by the battery pack 110. The low - voltage system includes 24 motor controllers (MCs) (2 for each of the 12 motors to provide redundancy), 6 tilt brakes (T - act) (1 for each tilt mechanism to tilt the corresponding pair of motors mounted on respective pylons), 4 aileron brakes (A - act), 2 elevator brakes (E - act), 1 rudder brake (R - act), an avionics unit (A - unit), a passenger system line replaceable unit (PAX - LRU), lights, and various other low - voltage systems. Each of the low - voltage systems is configured to operate at relatively low - voltage power (e.g., 28V nominal voltage).

[0037] Figure 2 Schematically illustrates the high - level aspects of supplying low - voltage power to the low - voltage system. The power distribution system 102 includes a low - voltage distribution subsystem 114 through which the battery packs 110a - f supply low - voltage power to the low - voltage system. In the illustrated embodiment, the power distribution system 102 includes six battery packs 110a - f. Each of the battery packs 110 includes two battery assemblies 116, 118. Each of the two battery assemblies 116, 118 includes a battery module 120 and a direct - current to direct - current (DC / DC) converter 122. In one example embodiment, each of the battery assemblies 116, 118 includes 10 battery modules 120. However, each of the battery assemblies 116, 118 can include any suitable number of battery modules 120. In each of the battery assemblies 116, 118, the battery modules 120 are electrically coupled in parallel to supply low - voltage input power (e.g., 36V to 75V) to the associated DC / DC converter 122. Each DC / DC converter 122 is configured to generate low - voltage output power (e.g., 28V nominal voltage), which is output from the battery assemblies 116, 118. In the illustrated embodiment, the battery packs 110a - f have a total of 12 battery assemblies 116, 118.

[0038] In the illustrated embodiment, the power distribution system 102 includes twelve power distribution units (PDU1, PDU12, PDU2, PDU22, PDU3, PDU32, PDU4, PDU42, PDU5, PDU52, PDU6, PDU62). Each of the twelve power distribution units receives low voltage output power from an associated one of the twelve battery assemblies 116, 118. The twelve power distribution units are connected to a suitable subset of the low voltage system to provide a suitable level of redundancy for the power supply of the low voltage system. Each of the twelve power distribution units may include power monitoring elements (such as voltage sensors, current sensors) and power control elements (such as controlled power transistors for isolating faults in any one or more of the battery assemblies 116, 118).

[0039] Figure 3 Schematically illustrates one of the battery banks 110a-f of the low voltage distribution subsystem and associated downstream components. Each of the battery banks 110a-f includes a first battery assembly 116 and a second battery assembly 118. In the illustrated embodiment, each of the battery assemblies 116, 118 includes six battery modules 120, an associated DC / DC converter 122, a battery management system (BMS) 124, and a pre-charge contactor / current sensing / bus bar 126. Although in the illustrated embodiment, each of the battery assemblies 116, 118 includes six battery modules 120, each of the battery assemblies 116, 118 may include any suitable number of battery modules 120, such as, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more battery modules 120.

[0040] The output terminals of each of the battery modules 120 in each of the battery assemblies 116, 118 are electrically connected in series to generate high voltage power that is supplied to the twelve motors 105a-105l. The resulting high voltage power generated by the battery modules 120 connected in series in the first battery 116 and the second battery 118 is electrically connected in parallel to produce a single high voltage power output from each of the battery banks 110a-f.

[0041] The output terminals of each of the battery modules 120 in each of the battery assemblies 116, 118 are electrically connected in parallel to supply low-voltage input power to the DC / DC converters 122. Each of the battery assemblies 116, 118 includes a diode 128 connected between the battery module 120 and the DC / DC converter 122. Each of the diodes 128 blocks current from flowing back into the associated one of the battery modules 120. Including the diodes 128 serves to cause the battery modules 120 with relatively higher state of charge to discharge preferentially over the battery modules 120 with relatively lower state of charge, because the battery modules 120 with relatively higher state of charge will output power at a relatively higher voltage, thereby inhibiting the battery modules 120 with relatively lower state of charge from outputting power. Each of the battery modules 120 will have an internal resistance, which causes a decrease in the output voltage as the power discharge rate increases, and this further serves to distribute the discharge of the battery modules 120 based on the relative state of charge and the total power supplied by the battery modules 120 to the DC / DC converter 122 at any given time point.

[0042] Each of the DC / DC converters 122 is configured to generate low-voltage output power from the low-voltage input power and supply the low-voltage output power to the associated one of the power distribution units (PDU1 - PDU62). Each of the DC / DC converters 122 includes a DC / DC circuit 130 and a controller 132. The DC / DC circuit 130 is configured to generate low-voltage output power from the low-voltage input power. The controller 132 is configured to monitor the voltage and / or current of the low-voltage input power and control the DC / DC circuit 130 based on the low-voltage input power to generate low-voltage output power within the voltage range of the low-voltage input power. In many embodiments, each of the DC / DC converters 122 is configured to create a voltage drop in the low-voltage output power to passively control the power distribution between the power distribution units that supply low-voltage power to the low-voltage systems of the aerial vehicle 100. Figure 4 An example voltage drop relationship that can be achieved by each of the DC / DC converters 122 is shown.

[0043] The DC / DC converters 122 are configured to accommodate different voltage ranges of the low-voltage input power supplied by the battery modules 120 while still generating low-voltage output power that has as Figure 4The voltage as a function of current as shown. For example, each DC / DC converter 122 can be configured to produce a low-voltage output power with a voltage of 30 volts for any resulting voltage within a suitable range (e.g., 36V to 75V) for a low-voltage input power at an output current (I-1), thereby accommodating the natural decrease in the output voltage of the battery module 120, which occurs during high instantaneous discharge rates during discharge of the battery module 120 due to the internal resistance of the battery module 120 and due to the cumulative decrease in the state of charge of the battery module 120. For example, Figure 5 A graph is shown that illustrates an example change in the battery module output voltage as a function of the state of charge of the battery module 120. Figure 6 A graph is shown that illustrates an example change in the battery module output voltage of the power distribution system 102 as a function of flight duration. The ability to generate a suitable low-voltage output power for use by the low-voltage system when the state of charge of the battery module is relatively low provides the ability to more fully utilize the power stored in the battery packs 110a-f to operate the low-voltage system, thereby providing an increased ability to support the continued safe flight and landing of the aircraft when the state of charge of the battery packs 110a-f is low.

[0044] Although described herein in the context of the aerial vehicle 100, the power distribution system 102, one or more battery packs 110a-f, and / or one or more battery assemblies 116, 118 can be employed in any suitable electric vehicle, system, or device. For example, any electric vehicle that receives at least a portion of its power from one or more batteries can be used in conjunction with embodiments of the present disclosure. In some instances, embodiments of the present disclosure are particularly suitable for use with aerial vehicles due to the reliability and fault isolation provided.

[0045] Other variations are within the spirit of the invention. Thus, although the invention is susceptible to various modifications and alternative constructions, certain illustrative embodiments of the invention have been shown in the drawings and described in detail above. However, it should be understood that the intention is not to limit the invention to the particular forms disclosed, but on the contrary, the invention covers all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the appended claims.

[0046] In the context of describing the present invention (particularly in the context of the following claims), the use of the terms "a", "an", "the", and similar referents are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by the context. The terms "comprising", "having", "including", and "containing" are to be construed as open-ended terms (i.e., meaning "including but not limited to") unless otherwise noted. The term "connected" is to be construed as being included, attached, or joined in whole or in part, even if there is something in between. Unless otherwise indicated herein, the recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein may be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by the context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein is merely intended to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise stated. No language in the specification should be construed as indicating any non-recited element as essential to the practice of the invention.

[0047] Preferred embodiments of the invention are described herein, including the best mode known to the inventors for practicing the invention. Variations of these preferred embodiments may become apparent to those of ordinary skill in the art upon reading the above description. The inventors expect those skilled in the art to appropriately adopt these variations, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, the invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. In addition, the invention covers any combination of all possible variations of the above-described elements, unless otherwise indicated herein or clearly contradicted by the context.

[0048] All references cited herein, including publications, patent applications, and patents, are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in full herein.

Claims

1. An aircraft electrical power distribution system for supplying electrical power to high-voltage propulsion loads and low-voltage system loads, the system comprising: A battery pack, the battery pack including a first battery and a second battery, wherein the first battery includes a first battery module and a first DC-DC converter, wherein the second battery includes a second battery module and a second DC-DC converter, wherein the first battery modules are electrically connected in series to generate a first battery high-voltage output, wherein the second battery modules are electrically connected in series to generate a second battery high-voltage output, wherein the first battery high-voltage output and the second battery high-voltage output are used to power a group of high-voltage propulsion loads, wherein the first battery modules are electrically connected in parallel to generate a first battery module low-voltage output, wherein the first DC-DC converter generates a first battery low-voltage output from the first battery module low-voltage output, wherein the second battery modules are electrically connected in parallel to generate a second battery module low-voltage output, and wherein the second DC-DC converter generates a second battery low-voltage output from the second battery module low-voltage output; A first power distribution unit that distributes the first battery low-voltage output to a first group of low-voltage system loads; And A second power distribution unit that distributes the second battery low-voltage output to a second group of low-voltage system loads.

2. The system according to claim 1, wherein: The first battery includes four first battery modules; and The second battery includes four second battery modules.

3. The system according to claim 2, wherein: The first battery includes five first battery modules; and The second battery includes five second battery modules.

4. The system according to claim 3, wherein: The first battery includes six first battery modules; and The second battery includes six second battery modules.

5. The system according to claim 1, wherein, The first battery high-voltage output and the second battery pack high-voltage output are connected in parallel to generate a battery pack high-voltage output, and the battery pack high-voltage output is supplied to the group of high-voltage propulsion loads.

6. The system according to claim 1, wherein: The first battery includes a first current flow control component connected between the first battery module low-voltage output and the first battery module to block current from flowing from the first battery module low-voltage output to the first battery module and to distribute the contribution of the first battery module to the first battery module low-voltage output based on the output voltage of the first battery module; And The second battery includes a second current flow control component connected between the second battery module low-voltage output and the second battery module to block current from flowing from the second battery module low-voltage output to the second battery module and to distribute the contribution of the second battery module to the second battery module low-voltage output based on the output voltage of the second battery module.

7. The system according to claim 6, wherein Each of the first current flow control component and the second current flow control component includes a diode.

8. The system according to claim 6, wherein: The first DC-DC converter is configured to generate a first battery low-voltage output from the first battery module low-voltage output to produce a first voltage drop in the first battery low-voltage output; And The second DC-to-DC converter is configured to generate a second battery low voltage output from the low voltage output of the second battery module to create a second voltage drop in the second battery low voltage output.

9. The system according to claim 8, further comprising: A second battery pack, the second battery pack including a third battery and a fourth battery, wherein the third battery includes a third battery module and a third DC-to-DC converter, wherein the fourth battery includes a fourth battery module and a fourth DC-to-DC converter, wherein the third battery modules are electrically connected in series to generate a third battery high voltage output, wherein the fourth battery modules are electrically connected in series to generate a fourth battery high voltage output, wherein the third battery high voltage output and the fourth battery high voltage output are used to power a second group of high voltage propulsion loads, wherein the third battery modules are electrically connected in parallel to generate a third battery module low voltage output, wherein the third DC-to-DC converter generates a third battery low voltage output from the third battery module low voltage output, wherein the fourth battery modules are electrically connected in parallel to generate a fourth battery module low voltage output, and wherein the fourth DC-to-DC converter generates a fourth battery low voltage output from the fourth battery module low voltage output; A third power distribution unit, the third power distribution unit distributing the third battery low voltage output to a third group of low voltage system loads; and A fourth power distribution unit, the fourth power distribution unit distributing the fourth battery low voltage output to a fourth group of low voltage system loads.

10. The system according to claim 9, wherein, The first power distribution unit, the second power distribution unit, the third power distribution unit, and the fourth power distribution unit are electrically connected to the low voltage system loads such that each of the low voltage system loads is powered by at least two of the first power distribution unit, the second power distribution unit, the third power distribution unit, and the fourth power distribution unit.

11. The system according to claim 9, wherein: The third battery includes four third battery modules; and The fourth battery includes four fourth battery modules.

12. The system according to claim 11, wherein: The third battery includes five third battery modules; and The fourth battery includes five fourth battery modules.

13. The system according to claim 12, wherein: The third battery includes six third battery modules; and The fourth battery includes six fourth battery modules.

14. The system according to claim 9, wherein, The third battery high voltage output and the fourth battery high voltage output are connected in parallel to generate a second battery pack high voltage output, the second battery pack high voltage output being supplied to a second group of high voltage propulsion loads.

15. The system according to claim 9, wherein: The third battery includes a third current flow control component connected between the third battery module low voltage output and the third battery module to block current from flowing from the third battery module low voltage output to the third battery module and to allocate the contribution of the third battery module to the third battery module low voltage output based on the output voltage of the third battery module; and The fourth battery includes a fourth current flow control component connected between the fourth battery module low voltage output and the fourth battery module to block current from flowing from the fourth battery module low voltage output to the fourth battery module and to allocate the contribution of the fourth battery module to the fourth battery module low voltage output based on the output voltage of the fourth battery module.

16. The system according to claim 15, wherein, Each of the third current flow control component and the fourth current flow control component includes a diode.

17. The system according to claim 15, wherein: The third DC-DC converter is configured to generate a third battery low voltage output from the third battery module low voltage output to generate a third voltage drop in the third battery low voltage output; And The fourth DC-DC converter is configured to generate a fourth battery low voltage output from the fourth battery module low voltage output to generate a fourth voltage drop in the fourth battery low voltage output.

18. A battery pack, comprising: A first battery, the first battery includes a first battery module and a first DC-DC converter, wherein the first battery modules are electrically connected in series to generate a first battery high voltage output, wherein the first battery modules are electrically connected in parallel to generate a first battery module low voltage output, and wherein the first DC-DC converter generates a first battery low voltage output from the first battery module low voltage output; And A second battery, the second battery includes a second battery module and a second DC-DC converter, wherein the second battery modules are electrically connected in series to generate a second battery high voltage output, wherein the second battery modules are electrically connected in parallel to generate a second battery module low voltage output, and wherein the second DC-DC converter generates a second battery low voltage output from the second battery module low voltage output.

19. The battery pack according to claim 18, wherein: The first battery includes four first battery modules; and The second battery includes four second battery modules.

20. The battery pack according to claim 19, wherein: The first battery includes five first battery modules; and The second battery includes five second battery modules.

21. The battery pack according to claim 20, wherein: The first battery includes six first battery modules; and The second battery includes six second battery modules.

22. The battery pack according to claim 18, wherein, The first battery high voltage output and the second battery pack high voltage output are connected in parallel to generate a battery pack high voltage output.

23. The battery pack according to claim 18, wherein: The first battery includes a first current flow control component connected between the first battery module low voltage output and the first battery module to block current from flowing from the first battery module low voltage output to the first battery module and distribute the contribution of the first battery module to the first battery module low voltage output based on the output voltage of the first battery module; And The second battery includes a second current flow control component connected between the second battery module low voltage output and the second battery module to block current from flowing from the second battery module low voltage output to the second battery module and distribute the contribution of the second battery module to the second battery module low voltage output based on the output voltage of the second battery module.

24. The battery pack according to claim 23, wherein, Each of the first current flow control component and the second current flow control component includes a diode.

25. The battery pack according to claim 23, wherein: The first DC-DC converter is configured to generate a first battery low voltage output from the first battery module low voltage output to generate a first voltage drop in the first battery low voltage output; And The second DC-to-DC converter is configured to generate a second battery low-voltage output from the low-voltage output of the second battery module, so as to generate a second voltage drop at the second battery low-voltage output.

26. A battery, comprising: A battery module, the battery modules being electrically connected in series to generate a first battery high-voltage output, wherein the battery modules are electrically connected in parallel to generate a battery module low-voltage output; and A DC-to-DC converter, the DC-to-DC converter generating a battery low-voltage output from the battery module low-voltage output.

27. The battery according to claim 26, wherein, The battery includes four of the battery modules.

28. The battery according to claim 27, wherein, The battery includes five of the battery modules.

29. The battery according to claim 28, wherein, The battery includes six of the battery modules.

30. The battery according to claim 26, further comprising a current flow control component connected between the battery module low-voltage output and the battery module to block current from flowing from the battery module low-voltage output to the battery module and to allocate the contribution of the battery module to the battery module low-voltage output based on the output voltage of the battery module.

31. The battery according to claim 30, wherein The current flow control component includes a diode.

32. The battery according to claim 26, wherein, The DC-to-DC converter is configured to generate the battery low-voltage output from the battery module low-voltage output, so as to generate a voltage drop in the battery low-voltage output.

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