UDT 2020 Lithium-Ion Batteries for Submarines: development and - PDF document

UDT 2020 UDT Extended Abstract Presentation/Panel UDT 2020 – Lithium-Ion Batteries for Submarines: development and operational benefits Marie LEVEQUE 1 , Hervé FERAL 2 and Anthony COVARRUBIAS 3 1 Lithium-Ion Batteries Project Director, NAVAL GROUP, Bouguenais, France, marie.leveque@naval-group.com 2 Lithium-Ion Batteries Architect, NAVAL GROUP, Lorient, France, herve.feral@naval-group.com 3 Business Development Senior Manager, NAVAL GROUP, Paris, France, anthony.covarrubiascastro@naval-group.com Abstract — In 2014, we had the opportunity to present at UDT Liverpool edition the vision of what Lithium-Ion technology could bring to submarines, describing what steps and considerations should be adopted in their integration on board [1], with special emphasis on the safety aspects. For this edition of UDT, we will present the development achieved by Naval Group in the integration of Lithium-Ion batteries onboard submarines, considering the high demands of safety, architecture and of course the operational advantages that respond to the demanding challenges of submarine warfare, describing the process that allowed us to move from a vision to a real and safe existing solution. 1 Introduction chemicals (batteries) and pyrotechnical components (weapons), human presence (crew). In addition to advances in sensors, weapons and stealth, the evolution of conventional submarines, begin to break Since the beginning of our development, the main factors the paradigm of the small submarine restricted to a small that were considered in the integration of this type of patrol zone at low speed waiting for a surface force. batteries were the chemical intrinsic stability, the use of Today conventional submarines are looking for long industrial cells, parameter monitoring and battery range deployments with an enhanced endurance, management, the arrangement architecture, the potential increasing in some cases their size and displacement. evolution offered by this technology and the most These advances must be accompanied by a coherent important topic, safety analysis methodology and power system, i.e. the main battery, which must be a expertize regarding safety barriers like physical, electrical source of energy that facilitates the submarine missions and thermal. and does not restrict them. To address these constraints, we managed several topics: With the need to increase the dived autonomy, improving the useful range of available capacity of the batteries, the 2.1. Architecture: lithium technology appears as a solution in which In order to obtain the best performances from the submarine designers have fixed their interest. technology, it was important to consider an arrangement of the LIB fully adapted to the submarine architecture from the first stages. This allowed taking advantage of 2 Main integration constraints of Li-Ion mass gain provided by LIB, without excluding a batteries on submarines possibility for retrofitting an existing submarine. This architecture must be adapted to evolve during the Even if Lithium-Ion battery (LIB) technology is strongly lifecycle of the submarine, according to expected widespread in the civilian field, especially in transport evolution of Li-Ion technology. Thanks to LIB flexibility applications, including maritime, as far as submarines are for arrangement on board, Naval Group opted for a concerned, Li-Ion is a new technology. Indeed, if the horizontal configuration, which provides more energy potential of LIB is enormous, so is the technical than the vertical arrangement. Another challenge of LIB challenge of its integration on board submarines. LIBs integration to a power plant was the short circuit current can certainly increase the operational performance of management, which becomes more relevant in a submarines, but how can several hundred strings be submarine network, where selectivity must be guaranteed integrated into a coherent system that will provide a to avoid blackouts. For this purpose, Naval Group submarine with the energy it needs? developed a specific solution of DC/DC converters in The main constraints respond to two specificities: order to optimize the global battery efficiency. Large quantities of energy to be stored, compared to - current civilian applications, Safety aspects related to the specific environment of - Moreover, the LIB unlike lead-acid battery must be submarines: confined atmosphere, co-localization of monitored by a BMS. In a submarine equipped with LIB

UDT 2020 Presentation/Panel UDT Extended Abstract the number of elementary cells imposes a huge number of String design include mechanical barrier to prevent the propagation of a possible thermal runaway and protect BMS electronics devices. Another challenge has also cells again high temperatures. been to have an easy access to the electronic, without removing the battery, which is particularly important for maintenance. 2.2.4. Battery Management System Fig.1. LIB architecture Naval Group has implemented a precise management of cells, through dedicated electronics, such as its charge/discharge, balance of voltage and a real surveillance of all individual cells parameters such as temperature, voltage, state of charge, remaining capacity. To control and monitor each string, a Battery Management Module (BMM) was integrated to each string in order to maintain this surveillance even in case of failure of the Master Battery Management Module 2.2.5. Safety validation conclusion 2.2. Safety Safety has been successfully validated through Due to the high-energy concentration and confined incremental tests: environment on board the submarine, feared events were Cell abusive tests to validate the chemistry; - identified with the corresponding causes. Module non-propagation tests to validate module - barrier; Pack non-propagation to validate pack barrier ; - Safety is based on the depth defense concept. This Internal short circuit test to verify that there is concept is applied by Naval Group for all submarine - neither impact on the battery, nor the submarine; designs. Safety barriers are defined at each level of the Water immersion ; battery. - Heat-exposure. - To prevent these risks and consequences, a series of tests were carried out to qualify the cells in abusive conditions, according to Naval Group methodology and expertise in 3 System validation process propulsion, energy and weapons integration on board submarines. Functional and environment tests have been performed: Short circuit management system test to validate the - 2.2.1. Chemistry concept of DC/DC converter and interactions between converts and between converters and Naval Group selected a chemistry considering its low circuit breaker. level of reactivity under abusive conditions. This choice Vibration and choc test to validate mechanical - does not rule out access in the near future to other conception. chemistries that may give a better overall advantage, with Functional tests on the BMS functions to validate - increased energy for the same level of safety. balancing, safety functions. EMC test on electronics. - 2.2.2. Cell manufacturing Finally, the performance of the system, with charge and discharge cycle tests on single and multiple strings, has With an experienced supplier in the development of LIB, been validated and the battery performance measured. capable of providing cells already developed for the civilian field with a good reliability and intrinsic safety. Fig.2. Validation test 4 Operational benefits 2.2.3. String Higher available energy: for the same battery volume Cells are organized in modules, modules in packs and on board, this means a prolonged submerged period. finally in strings (pack and control electronics). Modules and packs are placed on a specific casing with their own Reduced indiscretion rate: there is no charge rate sensors and electrical connectors. reduction while charging even for a full charge at sea. With the appropriate diesel generator set, the charging time will be less and in addition, due to this efficiency,