Post-Info Session Questions.pdf

UNCLASSIFIED

Thursday Feb 27, 2025 – Battery RFP – Information Session Q&A Documentation

1. The RFP specifically cites lithium-ion batteries. Will proposals for other battery chemistries be considered?

a. If there is a chemistry that matches or exceeds lithium-ion in terms of energy, lifetime, and safety characteristics, and it appears to be at a reasonably high TRL with respect to commercial industry production, then we would still be interested in seeing those proposals. Furthermore, there is no preference on the specific chemistry or cell energy density being targeted, as long as the requirements for 2.4 MWh worth of usable energy density (at the end of life) within the volume constraints.

2. Given the wide voltage range allowed, is it expected that the delivered system include full load rated power conversion equipment to provide additional safety and fault tolerance, or is the intent for the system to provide raw battery power to the host DC bus?

a. The host DC bus will provide any necessary power conversion to the final voltage requirements of the downstream loads. The intent is for the battery system to interface in that range of 210-355VDC, but there should be ability to scale up the battery string voltage higher if the requirement ever changes in the future. Additionally, power conversion equipment is not necessary, but if it is needed for the proposed system, that could be acceptable. Ultimately, energy content needs to be extracted within this voltage band of 210-

355VDC.

3. Is cooling water available for the energy storage media and/or power electronics? If so, what is the allowed temperature range and flow rate?

a. Cooling water could be available but specific temperature ranges and flow rates will not be provided at this time. Rather, we would be seeking for the proposal to specify the temperature and flow rate that is needed for the battery system.

b. Additionally, in the scenarios where the operational demand (discharge) on the battery is the highest, it should not be expected to have an active thermal management system available or powered. Therefore, our perspective is that thermal management shouldn’t be relied upon for the battery to simply function. It should be there to help with benefits such as lifetime by reducing the thermal fluctuations on the battery during routine or standby operational modes.

4. Is there a preference for air-cooled vs water-cooled system?

a. Our requirements are open to either, and there are compelling reasons to use either method. However, an active system can not be relied upon during the worst case operational discharge. It is also acknowledged that there are many examples in the large-scale battery world where catastrophic casualties have occurred or become worse when water was introduced in places it wasn’t supposed to be. However, each method of thermal management for a given battery architecture can be optimized in a different way. As long as it meets the needs of host asset and is sufficiently safe, it would be considered acceptable.

5. Is the expectation that the battery system would need to operate continuously at a 1C discharge rate (2.4 MW) during the full duration of discharge? (Alternately, what is the intended usage for the battery system, and what are the specific charging and discharging cycles it will undergo?)

a. The 1C discharge rate (2.4 MW) shows the upper limit of power needed during the maximum operational event. If the proposed battery system can meet the 1C rate, it should be able to meet the other varying demands on the system. The specific details of events can be described in greater detail at the contract negotiation and Functional Requirements Document state.

b. Also it should be noted that the 2.4 MW power capability is needed at the end of life. As such, the C-rate is expected to be lower at the beginning of battery life due to the expected reduction of energy capacity over the system lifetime. 2.4 MW is the constant power requirement.

6. How might the charging requirements be different from the [discharge] power capability of 1 C or 2.4 MW for the 2.4 MWh battery system? Would 1/2 C be acceptable?

a. Yes, 1/2 C charging rate should be acceptable. It is possible that the charging requirement could be relaxed further if needed, but that should be identified in the proposal.

7. Is there a reason for the 50V limit on modules, or the 30V preference for modules?

Will there be leeway for modules above 50V?

a. These values are taken from various electrical standards and internal maintenance manuals. If the proposed battery system has a module voltage higher than the 50V limit, that may still be acceptable. It would then be desired to understand the necessary actions or precautions to ensure that the module is below 50V during installation or maintenance evolutions for operator safety.

8. The RFP specifies cycle life at 1000 cycles of service life. Is one cycle defined as a full charge and a full discharge?

a. Similar to the question on power discharge capability, the capacity discharged during each cycle can vary. If the proposed battery system can meet a full discharge and full charge, we are reasonably confident that it could meet the varying partial, lower rate discharges that would be demanded of the system. Details of the varying cycle demands can be described in greater detail at the contract negotiation and Functional Requirements Document state.

9. Are there any limitations on the country of origin for the components?

a. The preference is that components would be domestic. However, it is acknowledged that many cells, battery system components, or aspects of the components would be sourced from foreign countries. For the purposes of the prototypes, the source country of origin is not as important. Future delivered systems would be to need to be discussed.

10. Does the system need to be installed as one big block, or will it have to be brought in as a series of smaller pieces via hatches?

a. We don’t have specific requirements here, but it is expected that an initial installation (with all the infrastructure and supporting, equipment) will be implemented as 1 big block with easier access. Attritable parts, or parts that are foreseen to need to be replaced in a second system such as modules with the active material inside them, should fit the volume requirement provided for the modules.

11. Regarding the requirement to self-charge using the host asset’s power bus, will there be “regen” on the power bus?

a. This will just be a normal power bus. It is not within our target use case to have “regen” in the traditional sense of large battery energy storage systems applied to the grid. Note that we are interpreting this question about regenerative charging as intermittent and somewhat uncontrolled charging like that performed on EV platforms.

12. Can you provide additional technical information on the power bus or characteristics on the voltage and power? Alternately, which power generation system is used to charge the batteries, and what is its operating voltage?

a. Additional technical details will be provided during contract negotiations and development of more detailed requirements for interfacing with the host asset. Note that, if the proposed battery system can interface with the host asset within the provided voltage band, it is expected that the battery system would be acceptable and compatible with our system.

13. Do you have a size or expectation of how large a portion of the system can be taken offline?

a. There is not a specific expectation for the portion of a system that can be taken down during a given scenario. We expect that to be dependent on the proposed battery system’s architecture and its concept of operation during various operating modes or casualties. The need to maintain operations during a credible casualty, combined with the portion of the battery that may be impacted during the credible casualty, should help determine the acceptable portion of the system that could be taken offline. This general logic also applies to maintenance that could occur when the battery is expected to be operational.

14. If liquid cooling is proposed, would there be water pumps available, or would the vendor have to define and select that as well?

a. We are interested in understanding both perspective and options in the proposal (i.e. What would the system look like if the vendor provided the water pumps? What would the system look like if the host provided the water pumps, and what are the required flow characteristics?).

15. Would you want a full scale build and test of the system? What kind of testing?

a. Ideally yes. At a minimum, we would expect that a representative number of modules, packs, strings, up to and including a full-scale build, would be operationally tested by the vendor during the period of performance for this contract. In addition to this, we would want to procure a certain number (to be determined in the future) of modules/strings for external safety testing.

There is a potential that we would procure up to an additional full scale system for safety testing, to confirm and/or complement the vendor testing, both with respect to operational and safety capabilities.

16. Does the S9310 testing need to be performed at the module level?

a. The invoked testing would depend on the system architecture. There may be different levels of testing in accordance with S9310 that may be acceptable.

At a minimum, a prospective module will need to go through S9310 to characterize safety performance within that program. Ultimately, we would need to understand and characterize the operational and safety performance of the battery system, and that will likely be accomplished through the combination of analyzing and testing several levels of the proposed battery system.

17. Is certification from external organizations required prior to final implementation?

a. Testing and certification will be necessary before future implementation.

Note that this RFP is for development of a prototype only, and additional unit purchase are not guaranteed at the present time. The extent of the testing will be dependent on the battery system and architecture, as well as the operations and casualty considerations.

18. Are there electrical testing requirements in terms of EMI or EMC?

a. The electrical testing requirements are not specified at this time, due to the nature of this program targeting determination of safety feasibility and targeted delivery of a prototype. If vendors believe significant risks to feasibility that might be incurred due to EMI or EMC standards, then those risks should be identified for consideration if pursued for contract.

19. Are there any requirements on communication from battery to the host, or any software related requirements? Alternately, What is the central control system with which the battery system must communicate for monitoring and remote control, and which protocol does it use?

a. Currently, there are no requirements on specific methods of communication for this feasibility development effort.

20. Are there any limitations on control power requirements?

a. There are no limitations, but it is our expectation that the proposal identifies the needs for control power based on the battery system architecture, and whether it would be internally provided or if the control power is needed from an external source. Where control power is required, this should count against the total system capacity (i.e. the net output of the system in terms of energy and power must not be reduced by the need for control power, which may power support loads such as thermal management systems).

21. Can the requirement for gas containment be clarified? Does all of the gas from credible casualty events need to be contained? Is it expected that non-hazardous gas should also be contained? How should the S9310 requirements be invoked?

a. First, the battery system should be designed such that it can meet the most stringent set of requirements for S9310, based on the expected casualties being applied to the given battery architecture.

b. Secondly, regardless of whether they are hazardous or non-hazardous, we would expect that the gases would be handled in some manner. This could include full containment, transfer to some pressure system, chemical making the gases inert, or potential filtering, to name a few methods. We would seek a recommendation from the vendor, based on the constituents of the released gas during the operational or casualty scenario.

22. What is an example of a credible casualty (RFP Requirement 1.17)?

a. The credible casualty is described as a discrete set of events, similar to how an organization might perform a fault tree analysis. The purpose of the set of events is to drive the design to have fault tolerance, even when a latent cell defect results in a thermal runaway of the cell, such that it does not exceed design limits. Said another way, the design should not allow exceeding of design limits during a thermal runaway, even when compounded by some initiating event and a related system failure in the most limiting location. Not exceeding design limits is interpreted to mean as a consequence, that in these scenarios, the latent defect causing a cell thermal runaway will not lead to propagation.

b. For this example, we will consider an over current condition from an externally applied short circuit at the system terminals. The system is described as 20 strings in parallel, where each string is made up of 10 series connected modules to achieve desired system voltage. Strings are connected in parallel as 5-string sub-groups with a fuse at their combined output. All four of the 5-string sub-groups are electrically connected in parallel to obtain total system capacity. Each individual string has a load rated contactor. Each module has a fuse at the positive and negative rail.

Inside the module is an array of lithium-ion cells to provide desired module voltage and current. The string contactor opening setpoint is lower than the fuse rating of the modules, and the string group (5 strings) fuse is rated at less than 5x the string contactor setpoint.

c. The initiating event of this example occurs when a bolted fault making electrical connection between the positive and negative connections of a string, between the string contactor and the 5 string fuse. The subsequent failure occurs when the string contactor of the affected string fails to open.

Additionally, a single cell within a module of the affected string goes into thermal runaway due to a latent manufacturing defect.

d. The resulting progression of the example casualty includes the module fuse clearing, interrupting the current path. The 5 string fuse opens to interrupt current from the other strings. The short circuit event compounded with the heat and effects of the single cell thermal runaway, do not exceed design limits of the cells. No further damage to the system occurs. No other cells undergo thermal runaway and therefore propagation does not occur.

23. On the concept of redundancy, could a design approach where multiple modules communicate to a centralized battery management system utilizing multiple, independent, discrete fiber optic signals so that you wouldn't have one single point of failure for all of your modules?

a. That could be a potential solution, but it doesn’t necessarily have to be implemented that way. Different solutions may be possible, dependent on the battery architecture and the approach to designing redundancy into the system.

24. What are redundancy, independence, and coincidence?

a. Redundancy = The use of multiple (more than one) components or features to ensure continued functionality in the event of a failure within the original component. In the example of sensors and control systems for a protective feature, a redundancy will continue to provide the desired functionality to activate the protective feature if the original component fails.

b. Coincidence = The use of an additional component or feature (beyond what is determined to be needed to meet redundancy) to prevent a false positive from activating a control feature. In the example of sensors and control systems for a protective feature, coincidence could require two sensors and their respective control systems to send a signal before the critical feature responds. This design technique can be especially important in situations where the activation of the critical features has the potential to impact continued operation of the system or to damage the system (e.g. disconnect contactor for battery pack, fire suppression system).

c. Independence = A design strategy employed which yields portions of a system, control system, etc. where a fault present on that portion of the system would not cause a fault or other adverse behavior on a different portion of that system. In the example of sensors and control features for a protective system, the opposite of independence would be a level of commonality within the system which allows a fault in one portion of the functional area of the architecture to adversely affect the redundant portion of the functional area of the architecture.

25. If full load rated power conversion equipment is not to be included, what is the expected/allowed changeover time from a controlled charging mode to a raw battery discharge mode?

a. Expected/allowed changeover time is not specified at this time, but this information may be discussed in greater detail during the contract negotiations phase. Vendors should provide a statement about how, and potentially at what threshold, changeover time from charge to discharge becomes an issue, as well as whether slower or faster changeover times are better for the proposed system.

26. What are the overall system weight requirements?

a. We don’t have a specific requirement for weight to provide at this time. Our expectation is that the battery system should be optimize for volume instead.

The total weight of the system should still be provided in the proposal.

Further details on weight can be provided later during the contract negotiations phase.

27. How is the space thermally coupled to the outside world (both in terms of available active cooling, and mechanical mounting).

a. Discussion can be provided and discussed during the contract negotiations phase. The vendor should identify the proposed interface requirements, which is expected to include the heat rate that the proposed battery system needs to reject heat at (e.g. BTU/hr during charge/discharge), required flow rates, required purity/cleanliness requirements or other relevant aspects for their cooling medium to integrate with the host asset.

28. What are the most critical operational conditions that must be evaluated during certification testing?

a. Requirements 1.16 and 1.18 discuss the concepts for continuity of power, protection posture, and safety for which the proposed battery system must meet. Operationally, it is expected that the most critical operational conditions would be the discharge power/energy requirements specified in the RFP, combined with the various credible casualties that may occur for a given battery architecture.

29. Should the battery design allow for on-site maintenance and replacement, or will replacements be carried out off the host asset?

a. The battery design should allow for an operator to enter the volume of the battery system to perform maintenance. Replacement of attritable parts, or parts that are foreseen to need to be replaced in a second system such as modules with the active material inside them, should fit the volume requirement provided for the modules. It is expected that changeout and replacement of components (not including initial installation) would be carried out of the host asset.

30. Will the battery be placed in a temperature-controlled enclosed space, or will it be exposed to varying humidity, vibration, and extreme temperature conditions? Is the battery expected to operate in areas prone to saltwater exposure, corrosive gases, or high vibration?

a. Beyond the requirements provided in the RFP, the proposal should identify the environmental boundary conditions that the proposed battery system is rated for.

Contracting/Procurement

31. Do you have a notional timeline or budget limit?

a. We do not have a specific timeline or budget in mind. We don’t want to drive or guide the cost or schedule identified in the proposals. Instead, the cost and schedule should be an accurate balance of the company’s capability and type of work/system development that is being executed. The span of potential schedules and budgets is large, dependent on whether the proposal’s design approach aims to develop a design from the ground up or if it seeks to leverage and adapt existing battery system designs.

32. When will we announce the RFP winners?

a. This answer is highly dependent on workload, proposal number/detail, and various internal priorities and pressures. NNL has to internally assess the proposals. We will notionally make a decision and downselect during the summer and then recommend 1 or 2 courses of action to our customer for approval. Our intended timeline is to initiate a contract and work in October

2025 (FY26).

33. Are you anticipating multiple awards?

a. There are always possibilities for multiple rewards based on the available funding, changing need, and the quality of the potential proposal and follow-on work.

34. Which contract vehicle or contract type will you use? Federal Acquisition Regulation (FAR) or Department of Defense's (DoD) Ordnance Technology Consortium (DOTC)?

a. NNL/FMP utilizes FAR and DEAR clauses, please visit our website for possible term sets that could be used for solicitation if awarded.

Navalnuclearlab.energy,gov

35. Will the contract be fixed price or cost plus?

a. I have no expectation for what is chosen, but I expect that it will reflect how you best choose to balance the execution of work and deliverables with the flexibility for system development.

36. What type of security clearance are you expecting?

a. The project is expected to progress into classified territory at the Controlled Unclassified Information (CUI) level and invoke the necessary information protection requirements. At this time, no specific security clearance will be needed. If that need arises, it would be discussed and supported via the contract negotiations.

37. Are there limitations on the employees working on project and their country citizenship?

a. It is expected that export controls and information protection requirements would be invoked on the contract. Further details of those requirements and limitations would be communicated and discussed during the contract placement phase.

38. If a vendor is considering submitting a proposal for developing the module from scratch as well as submitting a proposal for integrating existing commercial modules, can both be submitted? If so, should they be combined or presented as separate documents?

a. Yes. Both design approaches can be submitted for consideration in parallel.

To ensure clarity in the proposal content, it is requested that the 2 proposals are provided separately.

39. Do the company information, personnel profiles, and success cases count toward the required 5-page limit? Additionally, is there any possibility to extend this limit?

a. Upon reflection, the 5-page limit will be increased to 20-pages. The 5-page limit was intended to aid the evaluation team in comparing the vendors based on proposal content and technical merit. It is expected that the pages submitted under the limit will contain mostly, if not only, technical information. Additional information that is related to procurement, contracting, marketing, or otherwise can be provided is a separate from the technical proposal document.