Subsea Reserve Battery with Remote Replaceable Couplings
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Solution Overview
Problem
Subsea electrical power systems face reliability issues due to battery degradation over time, especially in harsh deepwater environments, requiring a power source that maintains high reliability and low maintenance with ease of remote replacement.
Innovation Solution
A reserve battery system is electrically coupled to a subsea control system, detachably attached via high-pressure connectors, which remains inert until activated, using chemistries like lithium alloy/iron disulfide thermal batteries or silver zinc batteries, and can be replaced remotely using a ROV, ensuring immediate power availability in critical situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary battery is used to provide continuous power, then the battery can immediately supply power when needed, but the battery degrades over time causing decreased reliability and reduced ability to hold charge
Solution Approach 1:
The power system is segmented into a primary battery for immediate power needs and a reserve battery for long-term reliability. The reserve battery remains inactive during storage, avoiding degradation, and can be activated when the primary battery fails or is insufficient.
Solution Approach 2:
The reserve battery is prepared in advance in an inactive state, with all necessary components (electrodes, electrolyte, separator) already in place but not yet engaged in electrochemical reactions. This preliminary preparation allows the battery to maintain full capacity during storage while being ready for immediate activation when needed.
2Duration of action of moving object
If a rechargeable battery is used to extend power duration, then the battery can be recharged multiple times, but the battery still degrades over time and requires monitoring and maintenance
Solution Approach 1:
The reserve battery is designed as a single-use, non-rechargeable unit optimized for long-term storage reliability rather than multiple charge cycles. After activation and use, the battery is replaced rather than recharged, eliminating the degradation issues associated with rechargeable batteries while providing sufficient power for the critical period needed.
3Duration of action of stationary object
If a reserve battery is used to maintain long storage life, then the battery avoids deterioration during storage, but the battery requires activation before use and may not be immediately ready
Solution Approach 1:
All components of the reserve battery (electrodes, electrolyte, separator, housing) are prepared and assembled in advance in an inactive state. The electrochemical components are positioned and connected, but the electrochemical reactions are prevented until activation. This preliminary preparation ensures the battery can transition from storage to full power delivery immediately upon activation without delay.
Solution Approach 2:
An activation mechanism serves as an intermediary between the inactive stored state and the active power-delivering state. This intermediary system (such as a breakable seal, removable barrier, or electrical trigger) allows controlled transition from storage to operation, ensuring the battery is immediately ready for use once the activation step is completed.
4Ease of repair
If the reserve battery is designed for remote replacement in subsea environments, then maintenance and replacement are easier, but the battery requires unique alterations and specialized connectors
Solution Approach 1:
The reserve battery is designed as a self-contained, modular unit with all necessary components (electrochemical cells, housing, connectors, activation mechanism) integrated into a single replaceable package. This segmentation allows the entire battery unit to be replaced as one component rather than requiring disassembly or repair of individual parts, simplifying remote replacement operations in subsea environments.
Solution Approach 2:
The battery housing and connector design incorporates universal features that allow the same basic unit to serve multiple functions and be compatible with different installation configurations. The standardized connector interface and housing design enable the battery to be replaced using the same procedure regardless of specific application, reducing the need for specialized tools or procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The reserve battery system provides ultrahigh reliability and ease of remote replacement, maintaining full power capacity for extended storage periods and ensuring immediate readiness in critical situations, such as controlling oil/gas flow on rigs, without degrading until activated.
Implementation Method 1
Reserve batteries are primary batteries which are inert until the battery is activated and used. More specifically, the active chemical components of a reserve battery are inactive until such time as the battery is needed
Implementation Method 2
using chemistries like lithium alloy/iron disulfide thermal batteries
Data Source
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AI summary
A subsea system includes an electrically powered control system for controlling the subsea system and a replaceable reserve battery electrically coupled to the control system to provide backup and/or supplemental power to the control system when the reserve battery is activated. The reserve battery is provided in a housing having a first coupling, the subsea system includes a second coupling, and the first and second couplings are detachably connectable to each other and include electrical connections so that the reserve battery is replaceable while the subsea system remains below the sea-surface.