N252-D10 TITLE: DIRECT TO PHASE II: High-Density Energy Storage System
OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials; Directed Energy (DE); Renewable Energy Generation and Storage
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.
OBJECTIVE: Develop a high-density energy storage system (HESS) for use with an existing medium voltage motor drive system.
DESCRIPTION: The Navy requires a +/- 1000 VDC, split bus HESS to deliver energy to a medium voltage motor drive. The system must store at minimum 1.1 megajoule (MJ) (Threshold) of energy, 5.5 MJ (Objective) and have a system capacitance that exceeds 2.3 Farad (F) (Threshold (T)), 11 F (Objective (O)). The energy storage system must be capable of both delivering power to a motor via a three-level neutral point clamped (NPC) inverter and accepting power from regenerative braking of the motor. Energy is supplied to the motor for approximately 0.5 seconds, with regenerative braking occurring over a span of 3-5 seconds. Then, energy is supplied to the motor for approximately 20 seconds, the bus is recharged, and the cycle repeats with variable time delay between cycles.
The HESS must be modular, meaning you can add or remove additional HESS units to change overall system capacitance. An individual unit should be no larger than 93in x 45in x 81.5in. Military standards should be referenced for shock (MIL-DTL-901E [Grade A]) [Ref 5], vibration (MIL-STD-167-1A [Type 1]) [Ref 6], electromagnetic interference (MIL-STD-461G) [Ref 4], and environmental factors (MILSTD- 810H) [Ref 3] since the system must be rugged to be viable.
The energy storage system must also interface with a charging power supply. Existing charging power supplies are capable of outputting 90 kW to each bus at 30 amperes; however, this likely will not be sufficient to charge a highly energy-dense bus in the time required. Therefore, an alternate charging system design, intermediate power electronics between the existing charging power supply and energy storage system, or a hybrid energy storage approach (e.g., using components with different characteristics to promote fast charging during initial motor start-up and maximum energy capture during regenerative braking) are all acceptable approaches and considered within scope. If a new charging system is proposed, it must accept 440 Volts (V), 3 phase AC power. The bus must be charged in 60 seconds (T) or 10 seconds (O) at start up. The charging system can be contained within the HESS cabinet, or a separate cabinet that should be no larger than 48in x 63in x 38in.
The HESS must have a locally operable disconnect switch that can be monitored. The system must be capable of being discharged to 0 V via an existing energy dump (resistor bank), must be maintainable, and must not prohibit maintenance of connected equipment. It must have a means of verifying that discharged components have a voltage value less than +/- 20 VDC.
The energy density of the system must surpass the limits of typical capacitors. _ The system must aim to minimize weight and volume. If applicable, a battery management system, or equivalent for alternate technologies, must be incorporated to monitor, control, balance, collect data, facilitate safe use of the system, and extend its life. Mean time between failures (MTBF) of the HESS must be greater than or equal to 27,000 operational hours that can be demonstrated via modeling.
Capacitors, as a commonly used method of energy storage, may be limited in energy density and ability to quickly store generated energy. Advances in supercapacitors, ultracapacitors, batteries, hybrid energy storage solutions, and other related technologies associated with high-density energy storage may be relevant. A modular or scalable approach is preferred to promote applicability for additional military and commercial use cases.
The proposed technology should also ensure that the prototype device can be:
PHASE I: For a Direct to Phase II topic, the Government expects that the small business would have accomplished the following in a Phase I-type effort and developed a concept for a workable prototype or design to address, at a minimum, the basic requirements of the stated objective above. The below actions would be required to satisfy the requirements of Phase I:
FEASIBILITY DOCUMENTATION: Offerors interested in participating in Direct to Phase II must include in their response to this topic Phase I feasibility documentation that substantiates the scientific and technical merit and Phase I feasibility described in Phase I above has been met (i.e., the small business must have performed Phase I-type research and development related to the topic NOT solely based on work performed under prior or ongoing federally funded SBIR/STTR work) and describe the potential commercialization applications. The documentation provided must validate that the proposer has completed development of technology as stated in Phase I above.
PHASE II: Develop a subscale prototype HESS. Validate and demonstrate that the proposed HESS technology meets requirements for charging, storage, delivering energy in a medium voltage motor drive system, and receiving energy generated by the motor. Develop plans for how the technology can be scaled to meet full-scale system requirements.
Assess the prototype focused on energy storage capacity, energy efficiency, heat dissipation, safety, maintainability, and integration compatibility with other system components. Scalability and cost-effectiveness of the proposed technology will also be explored and evaluated.
PHASE III DUAL USE APPLICATIONS: Develop a full-scale HESS design and integrate it into the existing medium voltage motor drive system, test the new system, and prepare for acquisition into the corresponding program of record.
Energy storage for vehicles and renewable energy storage are potential commercial markets for this technology.
REFERENCES:
KEYWORDS: Energy storage; High power density; Capacitors; Supercapacitors; Energy; Power; Batteries; HESS
** TOPIC NOTICE ** |
The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 25.2 SBIR BAA. Please see the official DoD Topic website at www.dodsbirsttr.mil/submissions/solicitation-documents/active-solicitations for any updates. The DoD issued its Navy 25.2 SBIR Topics pre-release on April 2, 2025 which opens to receive proposals on April 23, 2025, and closes May 21, 2025 (12:00pm ET). Direct Contact with Topic Authors: During the pre-release period (April 2, 2025, through April 22, 2025) proposing firms have an opportunity to directly contact the Technical Point of Contact (TPOC) to ask technical questions about the specific BAA topic. The TPOC contact information is listed in each topic description. Once DoD begins accepting proposals on April 23, 2025 no further direct contact between proposers and topic authors is allowed unless the Topic Author is responding to a question submitted during the Pre-release period. DoD On-line Q&A System: After the pre-release period, until May 7, 2025, at 12:00 PM ET, proposers may submit written questions through the DoD On-line Topic Q&A at https://www.dodsbirsttr.mil/submissions/login/ by logging in and following instructions. In the Topic Q&A system, the questioner and respondent remain anonymous but all questions and answers are posted for general viewing. DoD Topics Search Tool: Visit the DoD Topic Search Tool at www.dodsbirsttr.mil/topics-app/ to find topics by keyword across all DoD Components participating in this BAA.
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| 5/6/25 | Q. |
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| A. | (1) There is no hard minimum, but the motor performance will absolutely decrease with a lower voltage. The higher you can sustain the voltage, the better. I would (engineering judgement) consider it problematic if the bus voltage dropped below 500V.
(2) There is an energy dump (a large resister system) that is water-cooled. It is to be expected that there will be excessive electricity generated by the motor / generator during this 3-5 seconds. If this system can fully recharge from the regenerative motor, that would be ideal, but it is not a hard requirement because it shall also be capable of recharging from the ship. As the amount of energy recovered by the motor will not be consistent, any such system needs to also have the ability to fully recharge from the ship’s grid. (3) It is hard to say definitively, as the 20 seconds are actuated manually. I will simply say the energy required for this 20 second retract (resetting the system) will be low enough that the ship’s grid without an energy storage system likely will be sufficient. (4) The equipment will be kept indoors in an effectively air conditioned space. There exists a cooling water system for thermal management; the cooling water will not be chilled, but it will be heat-exchanged with the ocean water. If the ship is operating in the arctic, it will be close to freezing; if the ship is operating near the equator, it can be up to 100F. |
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| 5/6/25 | Q. | Is there a known cycle rate of discharge to discharge? |
| A. | The specified cycle time between discharge to discharge is 45 seconds as the required minimum capability. In practice, it will often vary and be longer than this time scale. | |
| 5/6/25 | Q. | All systems have some amount of hysteresis or delay. For the HESS, is there any advance signal or sensor that initiates the motor control before the 0.5 second run time to offset any delay of function? If not, is there an acceptable delay period prior to the energy dump? Or, can the proposed HESS incorporate a sensor to announce that a dump is needed and when? |
| A. | I do not know of a specified maximum delay between detection of the need to dump energy into the motor, versus the need to actually dump the energy into the motor. I would say it is simply necessary that the time between detection and total discharge of the threshold energy (1.1 MJ) must fall within 0.5 seconds or less. | |
| 5/3/25 | Q. | In the question and answers section: in the answer to question #1 it is stated that the stored energy is dumped to the motor during the 0.5 seconds to drive the cable. Is that energy dump the 1.1 MJ of the minimum or the 5.5 MJ of the Objective? If so, what powers the motor during the 20 seconds after the 3-5 seconds of regen; the regen or ship grid? Is the amount of regen energy variable with respect to the HESS ability to recharge from the regen? |
| A. | The Navy requires a device capable of energy storage (ex. capacitors, batteries, hydrogen fuel cells, novel-technologies, etc.) that after being charged up, it can discharge a minimum of 1.1 MJ to the motor in half a second, and ideally up to 5.5 MJ. The ship has (effectively) unlimited electrical energy, but it is far from capable of delivering the 2.2 to 11 megawatts of power we seek; therefore the ship already has an energy storage system, and the Navy is seeking an upgrade to hopefully increase the power and energy availability. Not every event will consume the full amount, but the ability to discharge 1.1 MJ minimum is essential. During the 3 seconds afterwards, the motor will be acting as a generator; it is desired (but not absolutely required) that the energy storage system can recover as much of this regenerated energy as possible, to both (1) reduce the load on the ship’s grid, and (2) reduce the need to “dump” the excess electrical energy. The 20 seconds after the event (motor spin up + regeneration) will be a manual actuation of the motor at a significantly reduced torque; ideally this energy storage device proposed will have enough recovered energy stored to power the motor during this time, but if not then the ship’s grid can provide sufficient power. | |
| 4/23/25 | Q. | Can you provide more context as to how this HESS will be used in a real world environment? It is ship based, that is clear, but can any more details be given for what type of work this system will do/support (use case examples)? |
| A. | The primary goal of this effort is to serve as an upgrade to the Advanced Arresting Gear, which is used on the new CVN-78 Ford-class aircraft carrier. The AAG consists of a spool known as the Purchase Cable Drum (PCD) that the arresting wire (purchase cable) wraps around, and sandwiched between the PCD is both an electric motor and a water brake. The water brake is effectively an upright dynamo, and absorbs the vast majority of the kinetic energy of an arresting aircraft. The electric motor has two functions: (1) to push the wire forward and start the rotary motion once it detects an aircraft caught the wire, to avoid excessive shock on the aircraft; and (2) to serve a regenerative brake, absorbing a small fraction of the aircrafts kinetic energy and allowing for fine tuning of the reacting torque. The first requirement, pushing the wire forward, requires a significant amount of power that the ship’s electrical grid alone cannot provide.
For this reason, Navy seeks a technology for an energy storage device, such that the ship’s electrical grid can charge it up, and then it can be fully discharged during the initial half-second that the motor pushes the wire forward. A secondary goal would be for this energy storage device to be able to be partially recharged via the energy generated by the motor / regenerative brake; this would reduce the load on the ship’s electrical grid, as well as reduce the amount of excess electrical energy that needs to be “dumped.” This is the context as to why the Navy seeks an energy storage technology. |
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| 4/10/25 | Q. | Comment: The DON SBIR/STTR Program Office provides notice that the Description of Direct to Phase II topic N252-D10 was updated on April 4, 2025 (noted in yellow above). |
| A. | Accurate topic requirements can be found at https://navysbir.com/n25_2/N252-D10.htm and https://www.dodsbirsttr.mil/submissions/solicitation-documents/active-solicitations. Previous versions of the topic found on other websites should be considered invalid. | |
| 4/8/25 | Q. | Given the requirement of achieving 171 Wh/L and 100 Wh/kg, are you specifically seeking purely battery or capacitor-based systems, or would you be open to considering a hybrid powerplant approach (engine + generator + power electronics + battery/cap) that could provide enhanced operational flexibility, extended endurance, and potentially reduced logistical burden in field operations? |
| A. | In this topic, we do not wish to limit ourselves to any particular technology; the goal nevertheless is energy storage. There is (effectively infinite) electricity available from the ship’s grid, but this grid will not supply the power necessary for our applications. We seek a battery-like solution that can be charged from an electrical grid, and then discharge at the energy and power levels we seek, meeting all of the requirements (ex. energy density) listed in the SBIR topic. While it is true that, at first glance, a battery or a capacitor technology is the likely best fit, we are open to any energy-storage technology, be it a tradition anode-cathode battery, a capacitor, a hydrogen fuel cell, a fly-wheel inertial generator, or any other energy-storage technology or a combination of technologies; provided our requirements are met and the device is practical and safe to operate. |