Single-phase thermally managed immersion battery pack with integrated components for marine vehicles

Abstract

The invention relates to a single-phase immersion thermally managed battery pack (BB) for a watercraft comprising: A sealed casing containing an internal heat transfer fluid, which casing is delimited by walls; Cells (1) positioned within the casing and immersed in the internal heat transfer fluid; said pack further comprising: At least one heat exchanger (19A, 19B) for heat exchange between the internal heat transfer fluid and an external heat transfer fluid, which exchanger is supported by a wall of the casing; At least one first pump (13) integrated into the casing for circulating the internal heat transfer fluid through the exchanger (19A, 19B); At least one second pump configured to pump fresh water or seawater surrounding the vehicle and circulate it through the exchanger (19A, 19B), which fresh water or seawater is the external heat transfer fluid. Figure to be published for the abstract: Figure 3

Description

Title of the invention: Single-phase thermally managed immersion battery pack with integrated components for marine vehicles. Technical field.

[0001] The present invention relates to a single-phase immersion thermally managed battery pack for a watercraft. The invention further relates to a watercraft comprising at least said battery pack.

[0002] The invention relates to the technical field of vehicle battery packs, and more particularly to battery packs for marine vehicles. More specifically, the technical field relates to the thermal management of a battery pack. State of the art.

[0003] Electric or hybrid vehicles require battery packs with greater power and capacity than those designed for internal combustion engine vehicles. This is because, in electric or hybrid vehicles, these packs also power the electric motor and therefore must deliver a greater amount of energy, and thus be more powerful and / or more numerous.

[0004] A battery pack generally consists of a sealed casing in which cells are positioned, each cell being able to store and release electrical energy. The charging and discharging phases of the cells are accompanied by the emission of heat, particularly for lithium-ion cells, which are commonly used in battery packs.

[0005] This heat emission can become detrimental to cell operation and must therefore be regulated. Indeed, the optimal functioning of a cell is limited to a given temperature range. If the temperature is too high or too low, the cells deteriorate and deform, thus becoming less efficient, or even dangerous.

[0006] This is why high-performance battery packs are generally immersed in a heat transfer fluid designed to circulate between the cells, regulating their temperature. Heat exchange occurs between the heat transfer fluid and the cells, cooling or heating them as needed. However, these fluids are generally toxic to the environment and to humans.

[0007] The most efficient thermally managed battery packs often operate by immersion with a two-phase fluid (which can therefore exist in a liquid and a gaseous state, depending on its temperature and pressure). The cooling of the two-phase fluid can be achieved by fluid / air exchanges, using a fan for example, or by fluid / fluid exchanges.

[0008] French patent application FR 2 727 247 A1 discloses a vehicle battery pack using a two-phase fluid. This fluid, in its liquid state, partially covers the cells located in the sealed casing. After being heated by the cells, it changes to a gaseous state and rises to the top of the casing. It then passes into a conduit where heat exchange occurs with cold air, which lowers its temperature. The fluid then returns to a liquid state, allowing it to fall back to the bottom of the casing. However, the battery pack described in this document is complex and bulky, and the cooling of the cells remains partial and uneven.

[0009] Patent application WO 2020 / 049248 A1 discloses another battery pack in which a two-phase fluid is used. A liquid phase of said fluid is located at the bottom of the cells, and a gaseous phase is configured to rise to the top of the casing, where it undergoes heat exchange to be cooled. This cooling then allows it to transition to a liquid state and fall back to the bottom of the casing. A bladder is also integrated into the battery pack; its volume variations maintain a constant pressure within the pack, thus making it relatively complex to manufacture and maintain.

[0010] All the battery packs described above use two-phase fluids, which makes them complex to implement and repair. Furthermore, while they are effective at cooling the cells, they are not suitable for heating them. Therefore, battery packs using a single-phase heat transfer fluid have been developed.

[0011] US patent application 2023 / 0006266 A1 describes a thermally managed battery pack using a single-phase fluid, thus configured to remain in a liquid state. However, the developed battery pack remains bulky, complex, and expensive to manufacture. Cooling the single-phase fluid is also complex, making it inefficient. In particular, it requires the integration of additional components, including conduits allowing the heat transfer fluid to pass outside the battery, resulting in a significant risk of leaks. Furthermore, these additional conduits introduce extra mass and require a larger quantity of heat transfer fluid.

[0012] The invention aims to overcome at least one of the drawbacks of the aforementioned prior art. More specifically, the invention aims to reduce the size of the single-phase immersion thermal management battery pack, as well as to facilitate its installation and maintenance. The invention also aims to reduce the manufacturing cost of said pack and to increase its safety. Presentation of the invention.

[0013] The solution proposed by the invention is a single-phase immersion thermally managed battery pack for a watercraft comprising: a sealed casing containing an internal heat transfer fluid, which casing is delimited by walls, cells positioned in the casing and immersed in the internal heat transfer fluid, said pack further comprising: at least one heat exchanger for heat exchange between the internal heat transfer fluid and an external heat transfer fluid, which heat exchanger is supported by a wall of the casing, at least one first pump integrated into the casing for circulating the internal heat transfer fluid in the heat exchanger, at least one second pump configured to pump fresh water or seawater surrounding the vehicle and circulate it in the heat exchanger, which fresh water or seawater is the external heat transfer fluid.

[0014] The term "single-phase thermally managed battery pack" refers to a battery pack whose cells are immersed in an internal heat transfer fluid (also referred to as the internal fluid in the remainder of this application). Preferably, this fluid is a high-boiling-point heat transfer fluid, or a single-phase heat transfer fluid. The use of such a fluid simplifies the manufacture of the battery pack, making it less expensive and less complex.

[0015] By "nautical vehicle" is meant any vessel, boat or drone for example that can be used for the transport of persons or goods, navigating without limitation on waterways such as rivers or streams, or on bodies of water such as lakes, seas or oceans for example.

[0016] By "sealed enclosure," we mean an enclosure that minimizes the passage of liquids or gases, thereby limiting leaks from the battery pack and the internal heat transfer fluid. Thus, a sealed enclosure helps to protect the environment. The enclosure walls can be external (to surround the battery pack and protect it from the external environment) or internal to the pack itself.

[0017] The internal fluid allows the cells to be thermoregulated in order to maintain their temperature within a range of optimal values ​​for their operation.

[0018] Preferably, the heat exchanger is positioned on an external wall of the casing and is oriented outwards, which reduces the risk of leakage by decreasing the number and length of the pipes used to circulate the various heat transfer fluids in the battery pack. Reducing the length of these pipes also leads to a decrease in pressure drop, making fluid circulation more efficient and also reducing the amount of heat transfer fluid required for its operation.

[0019] Reducing pressure losses and improving fluid circulation efficiency means that the first pump (also called the internal pump in the (This application) may be less powerful and smaller, but circulates the internal fluid with the same efficiency. The amount of energy required to circulate this fluid is therefore less.

[0020] The second pump (also referred to as the external pump in the remainder of this application) circulates fresh or seawater, thus reducing the size of the battery pack. This is because no additional external tank or heat exchanger is required to cool the external fluid, which is discharged directly into the waterway or body of water on which the vehicle is traveling.

[0021] Thus, the use of fresh or seawater simplifies the battery pack, making it less expensive and lighter. Furthermore, since heat exchange between two liquids is more efficient, it allows for the use of more compact heat exchangers with lower energy consumption. This, in turn, reduces the overall size of the battery pack.

[0022] Other advantageous features of the battery pack of the invention are listed below. Each of these features may be considered alone or in combination with the notable features defined above. Each of these features contributes, where applicable, to solving specific technical problems defined further in the description and in which the notable features defined above do not necessarily participate. The latter may, where applicable, be the subject of one or more divisional patent applications.

[0023] According to an advantageous embodiment, the first pump is positioned inside the sealed housing to be immersed in the internal heat transfer fluid.

[0024] Placing the first pump inside the battery pack housing reduces its overall size. Furthermore, installing such a pack is easy, and immersing the pump in the internal heat transfer fluid ensures its cooling, thus improving its lifespan.

[0025] Finally, this pump placement also improves cell temperature regulation by ensuring continuous and uniform fluid circulation. This reduces the length of the conduits required for its movement, thus simplifying the battery pack, making it less expensive, and reducing the risk of leaks. Therefore, improved cell temperature regulation also enhances their lifespan and performance.

[0026] According to an advantageous embodiment, the watertight housing is formed by a casing closed by a lid

[0027] The casing and the cover form the walls of the battery block, and more particularly its external walls, separating said block from the external environment.

[0028] Manufacturing a housing as a single unit with a cover allows the internal components of the housing to be adapted during manufacturing, particularly to the intended use of the battery pack. This also facilitates access to the internal components for maintenance or repair, thereby reducing costs. Furthermore, the rigidity, sealing, and strength of such a housing are improved.

[0029] The cover and / or housing can be conceptualized and adapted according to requirements. For example, they can be manufactured from different materials, which makes it possible to adapt manufacturing costs or their robustness.

[0030] Advantageously, the housing cover may include one or more pressure relief valves that are triggered when gas is present in the housing. These valves allow the trapped gas to be released into the external environment, thus limiting the risk of the battery pack exploding. Preferably, three pressure relief valves are positioned at intervals along the cover.

[0031] According to an advantageous embodiment: the first pump is located on one side of the housing, the heat exchanger is fixed to the cover and includes, on the same side as the pump, an inlet for the internal heat transfer fluid.

[0032] Attaching the heat exchanger to the cover reduces the space occupied by the battery pack, thus minimizing its overall size. Installation of the heat exchanger is also simplified.

[0033] Positioning the first pump laterally to the cells improves their cooling, thus optimizing the battery pack.

[0034] Finally, positioning the heat exchanger near the pump simplifies the internal layout of the coil block by reducing the number of pipes required for its operation. Furthermore, this eliminates the need for external pipes and a pump to transport the internal heat transfer fluid to an external exchanger. Reducing the number of pipes limits the mass of the coil block and improves its safety by preventing leaks of the internal fluid outside the block. This also reduces its manufacturing cost by limiting the amount of material required.

[0035] According to an advantageous embodiment: a suction conduit of the first pump is positioned near an upper face of the adjacent cell, and a circulation conduit extends from an outlet of the exchanger and is positioned in a bottom of the casing.

[0036] By "near" the upper face, it is meant that the suction duct is positioned a few centimeters from said face of the adjacent cell, and more preferably, at a distance of less than 8 cm from this face. This short distance improves the operating efficiency of the pump and the heat exchanger while reducing the amount of material needed to manufacture the battery pack. This therefore reduces its manufacturing costs and mass.

[0037] The efficiency of cell cooling is improved by positioning the circulation duct at the bottom of the housing, as the cooled fluid is reinjected there. This fluid, warming up upon contact with the cells, naturally becomes less dense and rises to the top of the housing. Since the suction duct is positioned near the top of the cells, it will draw in the warmer internal fluid. This results in more uniform cell cooling.

[0038] According to an advantageous embodiment, an internal circulation circuit of said block is configured to allow the circulation of the internal heat transfer fluid: from the first pump to the exchanger via a delivery conduit, from the inlet to the outlet of the exchanger, then from the circulation conduit connected to the outlet of the exchanger to the cells of the battery block in order to allow its reinjection into the sealed housing.

[0039] This internal circulation circuit improves the efficiency of heat exchange because it limits areas of stagnation of the internal fluid by improving its circulation, thus ensuring that the cells are thermoregulated uniformly.

[0040] According to an advantageous embodiment, the housing comprises at least one partition and a space arranged between said partition and the adjacent cells, this space receiving: the circulation duct comprising orifices, each orifice being positioned between two adjacent cells; and partitioning elements, each of these elements extending between one of the cells and the adjacent partition so as to form a sealed separation between two adjacent cells, each element being positioned vertically from the bottom of the housing to the upper face of the corresponding cell, each element partitioning the space arranged so as to force the internal heat transfer fluid to circulate from the circulation duct between, below, and above the cells.

[0041] The space provided between the housing partition and the cells allows the heat transfer fluid circulation duct to be held in position within the casing. The partition elements redirect the internal fluid circulation from this duct to all surfaces of the cells, making its circulation more efficient and uniform.

[0042] Advantageously, the circulation conduit also includes, at its free end, an orifice allowing the release of the internal fluid between an end partition of the housing and the large lateral faces of the adjacent end cells, so as to allow the cooling of all the faces of the cells.

[0043] Advantageously, the cells and partitioning elements are held in position by means of a lateral profile having a T-shaped cross-section. This profile bears respectively on the upper faces of the cells and on the adjacent partitioning elements.

[0044] Advantageously, another lateral profile with a T-shaped cross-section is positioned on the other side of the cells, between the side partition of the housing located near the first heat exchanger, and the adjacent cells. These two profiles allow the cells and / or partition elements to be held in position within the housing.

[0045] According to an advantageous embodiment, an external circulation circuit is configured to allow the circulation of the external heat transfer fluid, the circulation of said fluid being carried out from: a watercourse or body of water via an external supply conduit to an inlet of said fluid in the exchanger, positioned at the opposite end of the inlet of the internal heat transfer fluid, to an outlet of the exchanger positioned on the side of the inlet of the internal heat transfer fluid so that the external heat transfer fluid is evacuated from the exchanger via an external discharge conduit, and returned to the watercourse or body of water, the circulation being carried out by means of the second pump.

[0046] Integrating the heat exchanger onto the battery pack, which is usually external to said pack, improves the efficiency of heat exchange, thus enhancing the cooling or heating of the internal fluid. More specifically, this improves the thermal regulation of the cells. Consequently, the conduits normally required to transport the internal fluid to a heat exchanger and an external pump are eliminated. Finally, the overall size of the battery pack is reduced.

[0047] According to an advantageous embodiment: a cover is installed around the exchanger, and the exchanger is a plate exchanger comprising between 6 and 10 plates.

[0048] The heat exchanger cover improves the visual appearance of the battery pack, protects the heat exchanger plates, and also protects the various conduits or cables during installation or use of the pack. The cover is designed to allow for the easy addition of plates to increase the operating capacity of the heat exchanger by at least 30%, for example, to adapt it to a specific application.

[0049] The use of a plate heat exchanger also provides a larger contact surface area for regulating the temperature of the internal fluid, thus regulating its cooling and heating, thereby improving heat exchange. It also reduces the overall size compared to other types of heat exchangers, while being easily adaptable and simple to clean. Furthermore, these exchangers effectively separate different heat transfer fluids, limiting the risk of leakage. Finally, their manufacturing cost is relatively low, and their lifespan is longer.

[0050] According to an advantageous embodiment, the fixing of the exchanger on the cover is carried out at a distance of between 2 mm and 6 mm so as to free up a passage between the cover and the exchanger.

[0051] Fixing the heat exchanger away from the cover makes it easier to spot a leak from the cover.

[0052] Advantageously, the cover and the plates of the heat exchangers are fixed together on the lid by fasteners. Preferably, the distance between the heat exchanger and the lid is less than 4 mm, but never zero, so as to allow support for the seals positioned between the plates and to ensure the sealing of the heat exchangers.

[0053] According to an advantageous embodiment, each cell is positioned on a support so as to be at a distance from the bottom of the casing to allow the circulation of the internal heat transfer fluid under each cell.

[0054] The battery pack cells are placed on one or more supports which allows them to be positioned away from the bottom of the casing, allowing the internal heat transfer fluid that regulates their temperature to flow underneath. This therefore improves the durability of the cells and reduces their risk of thermal runaway.

[0055] According to an advantageous embodiment: two heat exchangers are fixed side by side on the cover; the inlet of the internal heat transfer fluid is positioned on a first heat exchanger and the outlet of said fluid is positioned on a second heat exchanger, said inlet and outlet being located at first ends of the heat exchangers oriented towards the pump; and a connecting conduit makes fluidic communication of the second ends of the heat exchangers, positioned opposite said first ends.

[0056] The presence of a second heat exchanger increases the thermal regulation capacity of the battery pack, thus improving its cooling or heating. Positioning the heat exchangers side by side on the cover reduces both the overall size of the pack and the length of the ducts required for its operation. This simplifies its manufacture and installation, while also improving thermal regulation and facilitating the circulation of the internal fluid.

[0057] According to an advantageous embodiment, the internal circulation circuit is configured to allow the circulation of the internal heat transfer fluid between the two exchangers: from the first to the second end of the first exchanger, then from the first to the second exchanger via the connecting conduit, and from the second to the first end of the second exchanger, before its reinjection into the sealed housing via the circulation conduit.

[0058] Passing the internal heat transfer fluid successively through the two exchangers increases heat exchange with the external heat transfer fluid, which improves their efficiency. Thus, with more efficient regulation of the internal fluid temperature, this reduces the amount of energy needed to maintain the cell temperature within an optimal range.

[0059] The presence of the second heat exchanger also ensures redundancy of the battery block. Thus, if one of the heat exchangers loses efficiency, the second can compensate for this deficiency and ensure the thermoregulation of the internal fluid.

[0060] According to an advantageous embodiment, the external circulation circuit is configured to allow the circulation of the external heat transfer fluid between the two exchangers: from the second to the first end of the second exchanger, then from the second to the first exchanger via a connecting conduit, and from the first to the second end of the first exchanger before its discharge into the watercourse or body of water.

[0061] The circulation of the external heat transfer fluid successively through the two heat exchangers optimizes heat exchange with the internal heat transfer fluid by increasing the exchange surface area between the two fluids. This improves the efficiency of temperature regulation of the internal fluid, thus improving its cooling or heating. Thermal regulation of the cells is therefore ensured.

[0062] According to an advantageous embodiment, the first pump is mounted on an electronic board comprising a battery pack control system, said board extending vertically in the sealed housing and parallel to the cells to be immersed in the internal heat transfer fluid, the battery pack control system being configured to control the operation of the first and second pumps at the housing.

[0063] Mounting the internal pump on the electronic board reduces the size of the battery pack, thus simplifying its design and internal layout. This simplification reduces the number of cables and conduits required for its operation.

[0064] The vertical arrangement of the electronic board and the internal pump optimizes the use of space within the housing and allows for a more compact battery pack design. This pump arrangement also improves the circulation of the internal heat transfer fluid and optimizes the thermoregulation of the cells, thereby increasing their lifespan and efficiency.

[0065] Immersing the battery pack control system (whose acronym is "BMS" in English) improves its cooling and increases its lifespan.

[0066] This control system manages the operation of the battery pack, and therefore controls the operation of the internal and external pumps that contribute to its thermal regulation. This control allows for optimal adaptation of the pumps' operation to The thermoregulation of the cells improves their efficiency and lifespan, while increasing the safety of the battery pack. The thermal management of the battery pack is therefore optimized.

[0067] According to an advantageous embodiment, the battery pack comprises: at least one pressure sensor for the internal heat transfer fluid, and / or a level sensor for said fluid, said sensors being mounted on the electronic board, controlled by the battery pack control system and immersed in the internal heat transfer fluid.

[0068] The pressure sensors detect gas releases from the cells.

[0069] The level sensor detects the internal fluid level in the sealed housing, thus serving to verify its cooling. Indirectly, it can also indicate the presence of a leak in the housing.

[0070] Since these sensors are managed by the battery pack control system, it can detect a problem and trigger the appropriate procedure. These sensors therefore allow for precise monitoring of the fluids and the battery pack, thus improving its safety.

[0071] According to an advantageous embodiment, one end of the cover comprises: power connectors; and / or control connectors for the battery block control system preferably mounted on a connector box, all of said connectors being partially immersed in the internal heat transfer fluid and positioned at a distance from the battery block control system.

[0072] The power connectors transfer the energy stored and released by the battery pack. The control system connectors transfer, in particular, data from the various sensors in said system. These connectors can also be used for the safety and control of the battery pack; therefore, they can activate protection circuits and control devices capable of interrupting or modulating the current, thus protecting the battery pack.

[0073] Installing the control connectors on a single housing simplifies their assembly, while also facilitating their management and possible replacement during battery block maintenance.

[0074] Positioning the various connectors so as to be partially immersed in the internal fluid improves their cooling, since each connector produces heat.

[0075] Advantageously, the connectors are mounted on the upper face of the cover. This arrangement facilitates the integration of the battery pack into the bottom of a watercraft.

[0076] According to an advantageous embodiment, at least two temperature sensors are installed in the battery pack and controlled by the control system of said pack, including a first sensor positioned at the inlet of the external circulation circuit and a second sensor positioned at the outlet of said circuit.

[0077] Temperature sensors measure the temperature of the external fluid and are therefore used to verify the efficiency of the heat exchangers. For example, when the temperature of the battery pack is too high, the heat exchange between the internal and external fluids occurs in such a way that the temperature of the internal fluid decreases between the inlet and outlet of the heat exchanger. Therefore, the temperature of the external fluid measured in this case is lower at the inlet of the heat exchanger compared to its outlet temperature.

[0078] Another example is when the temperature of the internal fluid in the battery pack is too low. In this case, the heat exchange between the internal and external fluids is carried out in such a way that the temperature of the internal fluid is increased from its inlet to the outlet of the heat exchanger. Therefore, the measured temperature of the external fluid is higher at the inlet of the heat exchanger than its temperature at the outlet.

[0079] The presence of temperature sensors located on the external circulation circuit therefore makes it possible to verify that the heat exchanges are carried out correctly.

[0080] Advantageously, one or more temperature sensors may also be present in the internal circulation circuit and allow the battery pack control system to know the temperature of the internal fluid, and to regulate the operation of the battery pack accordingly.

[0081] According to an advantageous embodiment, the cells of the battery block are sodium-ion cells connected to each other by busbars immersed in the internal heat transfer fluid.

[0082] Sodium-ion cells are more environmentally friendly and more economical to produce than lithium cells. They are also safer because their risk of explosion is lower. They are also particularly resistant to cold and can operate normally down to -20°C, so they do not require a heating system to maintain the internal fluid temperature within the optimal range for proper cell operation. As a result, these battery packs are simpler to manufacture and install, and are less bulky.

[0083] Alternatively, the cells may be lithium-ion cells, which are more efficient but require particularly precise temperature control. Heating the cells via the heat exchangers may be sufficient. However, for particularly low operating temperatures, an additional external heating device for the heat transfer fluid may also be added.

[0084] Immersing the busbars in the internal fluid improves their cooling, which limits cell heating. This improves the the operation and longevity of said cells and reduces the electrical resistance of the busbars.

[0085] According to an advantageous embodiment, two first pumps are immersed and mounted side-by-side on the electronic board comprising the battery block control system, each pump comprising a suction line with a non-return valve, this line being terminated by a filter.

[0086] The presence of two internal pumps allows one of the pumps to be replaced by the other if one of them stops working. Furthermore, the simultaneous operation of both pumps allows the thermal regulation capacity to be increased if necessary.

[0087] The positioning of the two pumps on the electronic board also reduces the size of the battery pack, and their immersion improves their cooling.

[0088] The presence of a non-return valve on each suction line prevents the backflow of internal fluid emitted by one of the pumps into the pump that is not operating. Finally, the filter prevents the introduction of particles or other elements into the pump, thus improving its lifespan.

[0089] The invention also relates to a watercraft used for the transport of persons or goods and comprising several thermally managed immersion battery packs, each battery pack being according to the invention, and each battery pack includes an external circulation circuit using fresh water or sea water, all of said circuits being partially fused upstream and downstream of the battery packs and being mounted in parallel so that: a single external cold water supply conduit comes from outside the watercraft and segments upstream of the battery packs to supply them individually, and external discharge conduits exiting the battery packs merge to form a single external discharge conduit containing the hot water, and returning this water to the watercourse or body of water.

[0090] For their operation, it is generally understood that watercraft have several battery packs, particularly in the case of electric or hybrid watercraft. Thermal management of these packs by single-phase immersion is particularly advantageous because the circulation circuits used are simplified and generally less expensive.

[0091] Using fresh or seawater to cool or heat the battery packs simplifies and reduces the load on the external circulation circuit, as no additional tanks, pipes, or external heat exchangers need to be installed. The water can be drawn directly, using a pump, from the yards or bodies of water. of water on which the vehicle travels. This simplification avoids any risk of leakage and reduces the volume of internal fluid needed circulating in the battery pack.

[0092] Merging the external supply and discharge lines upstream and downstream of the battery packs significantly simplifies the external circulation circuit, limiting the amount of material required for its production. This therefore reduces its cost and mass, while also decreasing the amount of energy required to move the vehicle and thus reducing the number of battery packs needed for its operation.

[0093] Supplying water in parallel to the exchangers of each battery block allows the same heat exchange efficiency to be maintained between said blocks.

[0094] Advantageously, the supply conduit may include, at its most distal end relative to the blocks, a filter limiting the introduction of particles into the external circulation circuit, which makes it possible to limit the premature degradation of said circuit. Brief description of the figures.

[0095] Other advantages and features of the invention will become more apparent upon reading the description of a preferred embodiment which follows, with reference to the accompanying drawings, which are provided by way of illustrative and non-limiting examples and on which: - [Fig. 1] shows a perspective view of a battery pack casing. - [Fig.2] shows a view of the case of [Fig.1] without the cover and without the heat exchangers. - [Fig.3] shows a side view of the battery pack of figures 1 and 2 without the case, representing an internal pump mounted on an electronic board. - [Fig.4] shows a perspective view of the battery block, with arrows reproducing the circulation of the internal heat transfer fluid. - [Fig.5] shows a top view of the battery block, with arrows reproducing the circulation of the external heat transfer fluid. - [Fig.6] shows an alternative embodiment of the invention, in which two internal pumps are mounted on the electronic board. - [Fig.7] shows a diagram representing a set of battery blocks with partially fused external circulation circuits. Description of the implementation methods.

[0096] As used here, and unless otherwise indicated, the use of the ordinal adjectives "first", "second", etc., to describe an object simply indicates that different occurrences of similar objects are mentioned and does not imply that the objects thus described must be in a given sequence, whether in time, space, ranking, etc. "X and / or Y" means: X alone or Y alone or X+Y. In general, it is appreciated that the objects are arbitrarily drawn to facilitate their reading on the various attached drawings.

[0097] The adverbs "upstream" and "downstream" are used in relation to the flow of fluid in the battery pack housing and / or in the circulation circuits of said pack.

[0098] By "external" we mean the components positioned outside the battery pack housing, and by "internal" we mean the components positioned inside this housing.

[0099] The term "watercourse" means navigable waterways such as rivers, streams and canals. The term "body of water" means navigable bodies of water, such as seas, oceans, and lakes, for example.

[0100] By "immersed" means that the component of the battery pack, for example a cell, a busbar or an electronic board, is totally covered by the internal heat transfer fluid.

[0101] In these figures, three axes are shown to position a battery pack in space. The x-axis represents the principal axis of the battery pack when it is in the mounting position, also called its length axis for a parallelepiped-shaped battery pack. The y-axis is the transverse axis to the x-axis in a horizontal plane when the battery pack is in the mounting position. It therefore extends along the width of the battery pack. Finally, the z-axis extends perpendicularly to the horizontal plane passing through the x and y axes; it represents the height of the battery pack when it is in the mounting position.

[0102] Figures 1 to 3 show different views of a battery pack according to the invention. These figures will be described together.

[0103] A BB battery pack according to the invention is generally intended for a watercraft and is used in particular to power its engine and to operate some of its components.

[0104] The BB battery block according to the invention comprises a plurality of cells 1 used for storing and releasing electrical energy. These cells 1 can take different shapes depending on their purpose, for example being cylindrical or prismatic.

[0105] In the context of the invention, the cells 1 of the battery block BB are preferably prismatic cells, the number of which varies between 8 and 24 cells per block. Each cell 1 therefore has two large lateral faces IA closed respectively at their upper and lower ends by an upper face 1B and a lower face IC, and laterally by two small lateral faces 1D.

[0106] The chemical composition of the cells 1 can also vary, affecting the power and capacity of the battery pack BB. Thus, lithium-ion cells are generally used in vehicle battery packs, allowing for greater power but requiring more efficient cooling. In the context of this As an invention, sodium-ion cells can also be used, as they have the advantage of being less expensive and less prone to overheating. These sodium cells also perform better at low temperatures.

[0107] In a battery block, two adjacent cells 1 are generally electrically connected by means of busbars 3 (visible in [Fig.2]) which allow current to flow between them.

[0108] The BB battery block of the invention further comprises a sealed housing 5 surrounding the cells 1, the shape of the housing 5 generally being correlated to the shape of said cells. In these figures, the housing 5 has a parallelepiped shape so as to accommodate a maximum number of prismatic cells. Its shape will also facilitate the integration of the BB battery block into the vehicle.

[0109] The housing 5 can be made of metallic materials such as aluminum, but it is preferably made of polymer materials, which are lighter and less expensive. Advantageously, the polymer housing is produced by pressure injection, the material preferably chosen being PA6+GF30% (polyamide filled with 30% glass).

[0110] The housing 5 is also delimited by walls forming, in particular, a casing 5A. This casing comprises two lateral partitions 5A.1 extending along the main x-axis of the battery pack, and two end partitions 5A.2 joining said lateral partitions 5A.1 together to form a parallelepiped-shaped housing. Thus, the end partitions 5A.2 extend along the y-axis of the width of said pack, and transversely to the lateral partitions 5A.1.

[0111] Advantageously, the cells 1 of the battery pack can be positioned in rows within the housing 5A. For example, these cells can be arranged in two rows of eight cells each, with two adjacent cells in the same row positioned so that their large lateral faces IA are opposite each other. The small lateral faces 1D of the cells in the same row are then positioned opposite one of the lateral partitions 5A.1 of the housing 5A. Preferably, two adjacent cells 1 in the same row are not placed next to each other; they have a gap between them to facilitate heat exchange. On each row, two end cells are also positioned at the ends of said row, so that one of their large lateral faces IA is opposite the adjacent end partition 5A.2 of the housing.

[0112] The housing 5A further comprises a base 5A.3 which supports and closes the cells 1, this base forming one of the walls of the housing. This base 5A.3 may also have reinforced areas in the form, for example, of edges or bumps, which will strengthen the housing 5A.

[0113] Advantageously, the cells 1 are positioned at a distance from the bottom 5A.3 by means of one or more supports 5A.4, which facilitate the flow of a heat transfer fluid under the cells. Preferably, each cell 1 is mounted individually on its own support 5A.4, each support having openings for the passage of said fluid.

[0114] The housing 5 further comprises a final wall forming a lid 5B, which seals the housing 5A. This cover is therefore complementary in shape to the housing. The cover 5B can be closed onto the housing 5A using any method known to those skilled in the art, such as welding or bonding. However, the use of fasteners is preferred, as it allows the housing 5 to be easily opened for maintenance, for example. These fasteners can be, for example, screws or bolts, which can secure the cover 5B and the housing 5A together thanks to the presence on each of them of holes configured to be positioned opposite each other when the housing 5 is in the closed position. A gasket can also be provided in this case to maintain the seal of the housing 5.

[0115] The cover 5B may also include, at one end of a top face, power connectors 5B.1 which transfer electrical energy to and / or from the battery block BB.

[0116] This cover 5B may also include control connectors 5B.2, these connectors being more preferably control connectors of the battery pack control system (whose English acronym is "BMS"), which can therefore control or transfer information to and from the battery pack BB.

[0117] This control system comprises a plurality of electronic components that control the various components of the BB battery pack, such as the cells, in order to manage energy transfer or to monitor it. Advantageously, the various control connectors 5B.2 are all mounted on a connector housing 5B.3, which facilitates their maintenance.

[0118] Other types of connectors may optionally be installed on the battery pack as required, such as safety or maintenance connectors, for example. Advantageously, these connectors (5B.1, 5B.2) are positioned close to each other to simplify the design of the battery pack. However, they could be positioned on different walls of the housing 5, such as on one of the side or end partitions (5A.1, 5A.2) of the housing 5A, for example.

[0119] The cover 5B further includes one or more overpressure valves 5B.4 which can release gases produced in particular by cells 1 in the event of Overheating. These 5B.4 valves reduce the risk of battery pack explosions. Three 5B.4 overvoltage valves are preferably positioned along the 5B cover.

[0120] The BB battery block further comprises at least one electronic board 7 on which the control system of said block is integrated. Preferably, in these figures, the BB battery block comprises two electronic boards 7.

[0121] A first card 7 is positioned vertically with respect to the cells 1, between one of the end partitions 5A.2 of the housing 5A and the adjacent end cells. This card is preferably positioned in the housing at an end opposite to the connectors (5B.1, 5B.2).

[0122] A second electronic board 7 extends preferably along the x-axis of the length of the battery block BB and above the cells 1, and more preferably at the junction of the two rows of cells. This second board 7 may include part of the control system for the battery block BB. The overvoltage relief valves 5B.4 are advantageously positioned above this second board 7.

[0123] In the housing 5 of the battery block BB, a space is also arranged between a row of cells 1 and one of the adjacent side partitions 5A.1 of the housing 5A, this space being sectioned by a plurality of partitioning elements 9. The number of partitioning elements 9 is identical to the number of cells 1, each element extending from the bottom 5A.3 of the housing 5A towards the upper face 1B of the adjacent cell 1.

[0124] Each element is advantageously positioned to be in contact with both the small lateral face 1D of cell 1 and the adjacent lateral partition 5A.1. Preferably, these elements extend over only a portion of the small lateral face 1D, preferably less than 75%, and even more preferably less than 50%, of the total surface area of ​​the corresponding small lateral face. These elements are preferably made of elastomers such as natural or synthetic rubbers, polychloroprene, or silicone, but other elastomers known to those skilled in the art and capable of providing a seal may be considered. This partitioning ensures homogeneous circulation of the heat transfer fluid between all the cells.

[0125] On the other hand, no space with partitioning elements is provided between the other side partition 5A.1 of the housing 5A and the small side faces 1D of the adjacent cells.

[0126] The BB battery block further comprises two lateral profiles 11 extending along the x-axis between the side partition of the housing 5A, the cells 1 and / or said elements, these profiles serving to retain the cells and / or the elements of partitioning in position in the housing. Each profile 11 has a T-shaped cross-section, comprising an upper portion 11A and a lower portion 11B.

[0127] On the side of the housing 5A where the partition elements 9 are located, the upper portion 1 IA of the profile 11 extends both over said elements and over each upper face IB of the adjacent cells 1. Its transverse portion 11B therefore extends between said elements and the small lateral faces 1D of the adjacent cells.

[0128] On the other side of the housing 5A, where the cells 1 are positioned near the other lateral partition 5A.1, the upper portion 1IA of the profile 11 extends over one upper end of said partition and over the upper faces IB of the adjacent cells 1. The transverse portion 1IB of said profile therefore extends between said partition and the small lateral faces 1D of the cells 1.

[0129] Each profile 11 can also be fixed to the cells 1, to the side partition 5A.1 of the housing 5A, or to the corresponding partition elements 9 using methods known to those skilled in the art, such as gluing. Preferably, these profiles 11 are held in position by fasteners so that they can be easily removed during maintenance of the battery pack BB.

[0130] However, for optimal operation, the cells 1 of the BB battery pack must be maintained within a specific temperature range. Therefore, thermal regulation of the BB battery pack is provided. This regulation consists of cooling it when the temperature of the pack exceeds the optimal operating temperature range, or heating it when its temperature falls below this range. Exceeding the temperature range may be caused by prolonged operation of the battery pack, excessive ambient temperature, or very high charge / discharge currents. A temperature below this range may occur during the start-up of the pack, particularly when the ambient temperature is too low.

[0131] The temperature regulation of the battery pack consists of circulating an internal heat transfer fluid (also referred to as the internal fluid in this application) which flows between, under, and over the cells 1. A "heat transfer fluid" is understood to be a fluid that can transport or dissipate heat. It can thus cool or heat them as needed. The thermal management of the battery pack BB is achieved here by immersion, meaning that the cells 1 are completely immersed in the internal heat transfer fluid.

[0132] The internal heat transfer fluids used in the present invention have a high boiling point, that is to say, they only transition to a gaseous state at temperatures above 190°C, or even above 300°C. These fluids include for example silicone or mineral oils, fluorocarbon-based fluids or polyalphaolefins.

[0133] Preferably, the heat transfer fluid chosen for these BB battery packs is an ester. Esters offer several advantages over other heat transfer fluids. First, they have good thermal conductivity, making them particularly efficient at transferring heat. Furthermore, they also have a high specific heat capacity, allowing them to store and transport a large amount of heat. Esters are also particularly chemically stable, which reduces the risk of corrosion of the BB battery pack and increases its shelf life. In addition, they are less toxic, less flammable, and biodegradable.

[0134] Advantageously, the internal heat transfer fluid also covers the electronic boards 7, the busbars 3, and the portion of the connectors (5B.2, 5B.1) located inside the housing, thus promoting their cooling and improving the efficiency of the battery pack. An air gap can also be provided above the upper faces IB of the cells 1 and below the cover 5B, allowing the housing 5 to adapt to a change in the volume of the internal fluid (particularly caused by a change in its temperature).

[0135] The BB battery pack may also include one or more internal fluid pressure sensors. These sensors are used to detect the presence of gas release from one or more cells, thus detecting whether the cells have degraded. The presence of several pressure sensors at various locations within the BB battery pack ensures redundancy in the fluid pressure measurements taken.

[0136] The battery block BB may also include a fluid level sensor that detects the level of internal fluid present in the housing 5 and ensures proper cooling of said block. Additional level sensors may be positioned within the battery block BB to provide redundancy in the measurements obtained. These level sensors may indirectly detect an internal fluid leak from the housing 5.

[0137] Advantageously, other types of sensors can also be positioned in the BB battery block, such as, for example, one or more fluid temperature sensors. Generally, all sensors in the BB battery block are managed by the control system and serve to verify the proper functioning of the block and to adapt its operation accordingly.

[0138] All of these sensors are preferably immersed in the internal fluid, which allows them to be cooled and increases their lifespan. They are advantageously positioned on the first and / or second electronic boards 7.

[0139] Thus, the thermal management of the BB battery block requires an internal circulation circuit comprising at least one first pump 13 (also called the internal pump), positioned inside the housing 5 and used to circulate the internal fluid within said block. This pump is immersed in the internal fluid to be cooled during operation. Advantageously, it is positioned on one side of the housing 5 so as to be oriented laterally to the cells 1. It is more preferably mounted on the first electronic board 7, thus reducing the overall size of the BB battery block. This pump 13 is advantageously controlled by the control system of said block.

[0140] Alternatively, this pump can be fixed to one of the walls of the battery pack forming the housing or cover. It can be positioned on the outside of the housing, or on the inside. When the pump is positioned on the outside of the housing, channels will allow circulation to and from the pump within the battery pack. This pump could optionally be mounted on an internal wall of the housing, if one is present. These variations are not shown in these figures.

[0141] The internal pump can be, for example, a direct drive cooling (DDC) pump, which is particularly well-suited for integration into the housing 5. It is compact, powerful, and ideal for battery packs using an internal liquid heat transfer fluid. This pump includes a self-adjusting spherical rotor and pulse width modulation (PWM) control for precise speed management. It is constructed from corrosion-resistant materials. These characteristics ensure efficient heat dissipation, increased reliability, and quiet operation with minimal maintenance.

[0142] The internal circulation circuit further comprises a suction conduit 15 terminating in a filter 15A, which carries the internal fluid from the housing 5 to the internal pump 13. The term "conduit" means a flexible hose, a rigid conduit, a tube, or a circuit formed within one or more partitions that allows the passage of a fluid. The filter 15A prevents particles produced by the wear of the battery block BB from being drawn into the pump 13. This filter is preferably positioned high up in the housing 5 in order to collect the hot internal fluid and send it to the pump 13. Preferably, it is positioned near the upper face IB of the adjacent end cells.

[0143] The internal circulation circuit also includes a sending conduit 17 for the internal fluid, allowing its passage from the internal pump 13 to one or more heat exchangers (19A, 19B) in order to allow for heat exchange. In Figures 1 and 3, two heat exchangers (19A, 19B) are shown, but a smaller battery pack could have only one heat exchanger and a larger battery pack could have more than two heat exchangers.

[0144] In the context of the invention, the heat exchanger (19A, 19B) is preferably a plate heat exchanger because it maximizes heat exchange, thus maximizing the cooling or heating of the internal fluid. Each heat exchanger (19A, 19B) is configured to include between 6 and 10 plates, this number varying according to the desired thermal management capacity. Indeed, the plates of a heat exchanger are fixed together by fastening devices that can easily accept additional plates.

[0145] Each heat exchanger (19A, 19B) is preferably surrounded by a cover (19A.3, 19B.3) which protects it, this cover (19A.3, 19B.3) being configured to receive a ten-plate heat exchanger. This therefore improves its modularity.

[0146] Advantageously, each heat exchanger (19A, 19B) is configured to be mounted on the cover 5B at a distance of between 2 mm and 6 mm and preferably at a distance of less than 4 mm. This distance allows the BB battery block to remain compact.

[0147] Alternatively, but not preferably due to its size, the heat exchanger may be a shell and tube heat exchanger. The use of such a heat exchanger can be advantageous in the marine sector, as these exchangers are constructed from resistant materials, thus exhibiting increased durability in corrosive environments. They are also easy to clean and are very efficient at heat exchange.

[0148] In Figures 1 and 3, a first heat exchanger 19A and a second heat exchanger 19B are configured to extend over a portion of the cover 5B, preferably over at least 50%, and more preferably over at least 75% of said cover. These heat exchangers (19A, 19B) comprise a first end (19A.1, 19B.1) positioned near the internal pump 13, and a second end (19A.2, 19B.2) positioned near the connectors (5B.1, 5B.2).

[0149] Alternatively, the heat exchanger can be mounted on a wall of the housing other than the cover. Thus, the heat exchanger can also be mounted on one of the bulkheads of the casing. The inlet and outlet ducts of the heat exchanger will be adapted accordingly.

[0150] The supply conduit 17, which originates from the internal pump 13, is preferably inserted at an inlet located at the first end 19A.1 of the first heat exchanger 19A. At the second ends (19A.2, 19B.2) of the first and second heat exchangers (19A, 19B) are two second heat transfer devices (23A, 23B) respectively. These devices are in communication The fluid is transferred via a connecting conduit 21 and is positioned on the covers (19A.3, 19B.3) of the heat exchangers. Thus, the second transfer device 23A recovers the internal fluid from the first heat exchanger 19A and sends it, via the connecting conduit 21, to the second transfer device 23B, which then transfers it to the second heat exchanger 19B.

[0151] The outlet of the internal fluid of the second heat exchanger 19B is located at its first end 19B.1, a circulation conduit 25 extending from said outlet, vertically and laterally to the internal pump 13. This conduit extends into the bottom 5A.3 of the housing 5A, more specifically into the space located between its lateral partition 5A.1 and the small lateral faces 1D of the adjacent cells 1, before ending near its end partition 5A.2 located opposite the internal pump 13. The positioning of this conduit allows for better distribution of the internal fluid and improves the thermal management of the battery block BB.

[0152] Orifices are positioned along the entire length of the circulation conduit so as to inject the internal fluid near the junction between two large lateral faces IA of two adjacent cells 1. This conduit 25 also terminates in an orifice that injects the internal fluid between the end partition 5A.2 and the large lateral faces IA of the adjacent end cells. Thus, thermal regulation of all the cell faces and connectors (5B.1, 5B.2) is achieved.

[0153] The BB battery pack also includes an external circulation circuit that carries an external heat transfer fluid to the heat exchangers (19A, 19B) to regulate the temperature of the internal fluid. This external fluid can be fresh water or seawater, which are readily available on a marine vehicle.

[0154] This external heat transfer fluid (also referred to as the external fluid in this application) is supplied to the BB battery pack by means of a second pump (also called the external pump). Alternatively, there may be several external pumps, particularly in the case of a large watercraft. However, the use of a single pump is preferred, as it helps to reduce the size of the battery pack.

[0155] The external pump can be positioned upstream or downstream of the battery pack on the external circulation circuit to allow circulation of the external fluid. It can be installed separately from the battery pack, or optionally mounted on the outside of one of the walls of the housing of said pack.

[0156] The external pump (visible in [Fig. 7]) can draw external fluid from a stream or body of water and deliver it via an external supply conduit (visible in [Fig. 7]) to the heat exchanger of the battery pack. This conduit may include one or more filters at its distal end, particularly if said pack is integrated into a watercraft, in order to limit the introduction of particles into the circuit. external circulation. The external pump can be powered electrically by the battery pack or by an external source (e.g., the ship's 12V circuit).

[0157] This external supply conduit is mounted at the second transfer device 23B via an external fluid inlet fitting 23B.1, positioned above the second end 19B.2 of the second heat exchanger 19B. Generally, the second transfer devices (23A, 23B) are configured to allow for a tight separation between the internal and external fluids and prevent them from mixing. Alternatively, a second transfer device mounted on a cover can form two separate devices, each receiving either the internal fluid or the external fluid ([Fig. 1]).

[0158] A first transfer device (27A, 27B) is also respectively positioned above the first ends (19A.1, 19B.1) of each of the first or second exchangers (19A, 19B). These devices are in fluidic communication via a junction conduit 29, which transfers only external fluid.

[0159] The term “first” in the expression “first transfer device” describes the transfer device according to its positioning at the first end (19A.1, 19B.1) of the corresponding heat exchanger (19A, 19B). Similarly, the term “second” in the expression “second transfer device” describes the positioning of said devices at the second ends (19A.2, 19B.2) of the corresponding heat exchangers.

[0160] A bypass fitting 23A.1 is positioned at the second transfer device 23A located at the second end 19A.2 of the first heat exchanger 19A, on which an external discharge pipe will be mounted. This pipe will serve to discharge the external fluid from the battery block BB and return it to the watercourse or body of water.

[0161] Advantageously, the temperature sensors are located at the inlet and outlet of the external circulation circuit, respectively at the external fluid inlet of the second heat exchanger and the external fluid outlet of the first heat exchanger. These sensors measure the temperature of the external fluid upstream and downstream of the heat exchangers in order to determine whether heat exchange with the internal fluid is occurring.

[0162] The circulation of external and internal fluids in the different circulation circuits are described in Figures 4 and 5, in correlation with Figures 1 to 3.

[0163] The circulation of the internal fluid is more particularly represented by means of arrows in [Fig.4]. This fluid is drawn in by the internal pump 13 at the filter 15A located at the end of the suction line 15. After passing through the pump 13, the fluid is injected into the delivery line 17 to reach the inlet of the first heat exchanger 19 A.

[0164] The internal fluid then flows from the first 19A.1 to the second end 19A.2 of the first exchanger 19A, from where it is sent into the second device of transfer 23A. This fluid then passes into the connecting conduit 21 and enters the second transfer device 23B, which transfers the internal fluid to the second end 19B.2 of the second heat exchanger 19B. The fluid then reaches the outlet of the heat exchanger 19B located at its first end 19B.1. The circulation conduit 25, attached to said outlet, allows the internal fluid to be reinjected into the housing 5 through the various orifices located along said conduit.

[0165] Each of these orifices being preferably located near the space between two adjacent cells 1, it will allow the introduction of the internal fluid between two large lateral faces IA opposite said cells, or between the large lateral faces IA of the end cells and the end partition 5A.2. Furthermore, the positioning of the cells 1 on their support 5A.4 allows the internal fluid to pass beneath their lower face IC. Since the cells 1 are immersed, their upper face IB can be thermally regulated as required. Thus, all faces of the cells and the associated busbars 3 can be cooled.

[0166] Finally, the presence of the partition elements 9 forces the circulation of the fluid between the large lateral faces IA of the cells 1, and prevents its backflow towards the internal pump 13. This improves the efficiency of the thermal regulation of the battery block.

[0167] The heated internal fluid will rise to the top of the housing, where it can again be drawn in through the suction conduit 15 of the pump 13.

[0168] The circulation of the external fluid in the external circulation circuit is more specifically represented in [Fig.5] by arrows.

[0169] The external fluid is supplied to the housing 5 of the battery pack BB via the external supply conduit, connected to the inlet fitting 23B.1 of the second transfer device 23B. The fluid is propelled by the external pump (shown schematically in [Fig. 7]). This pump can be electrically powered by the battery pack or by an external source (e.g., the ship's 12V circuit).

[0170] Next, this second transfer device 23B injects the external fluid into the second end 19B.2 of the second exchanger 19B, the fluid joining its first end 19B.1 to be recovered by the first transfer device 27B. This device then transfers the external fluid to the junction conduit 29, which injects it into the first transfer device 27A.

[0171] This device 27A then injects the external fluid into the first end 19A.1 of the first exchanger 19A, the fluid then flowing to its second end 19A.2 where it is recovered by the second transfer device 23A. The fluid is then sent into the external discharge conduit via the discharge fitting 23A.1, and is reinjected into the watercourse or body of water on which the watercraft is traveling.

[0172] Since heat exchange takes place in the heat exchangers (19A, 19B), the heat produced by the BB battery pack can be recovered by the internal fluid and transferred to the external fluid, from where it will be discharged. Alternatively, heat can be drawn from the external environment by water and returned to the heat exchangers, where it can be recovered by the internal fluid and used to heat the cells for optimal operation.

[0173] In the case where there is only one heat exchanger, the inlet of the internal fluid is preferably located near the internal pump in order to limit the length of the conduits, and the outlet of the heat exchanger is preferably positioned at its opposite end. The circulation conduit then extends from the outlet along the bottom of the housing and near the cells, so as to achieve heat exchange with the same efficiency. The circulation of the external fluid is preferably reversed with respect to the circulation of the internal fluid.

[0174] The circulation of heat transfer fluids in their respective circuits is also simplified.

[0175] Thus, the internal fluid is drawn through the suction line filter by the internal pump. It passes through the pump again to be sent to the heat exchanger via the delivery line. After entering the first end of the heat exchanger, the fluid circulates along the length of the exchanger to its second end and reaches the outlet to which the circulation line is attached. The internal fluid then flows down this line to be reinjected into the housing through the various orifices positioned along its length.

[0176] The internal fluid circulation in the casing is achieved in the same way, the presence of the various partitioning elements allowing the fluid to be forced between the large lateral and lower faces of the cells.

[0177] Since the flow of the external fluid is reversed compared to the internal fluid, the external fluid is brought to the housing via the external supply line. This line is mounted on the inlet fitting positioned on the second transfer device located above the second end of the heat exchanger. This device injects the external fluid into said end, the fluid then reaching the outlet positioned at the first end of the heat exchanger to be collected by the first transfer device and sent to the external discharge line via the discharge fitting. The external fluid is also propelled by the external pump, which can be positioned, as before, before or after the battery pack, and optionally mounted on said pack. This external pump can be electrically powered by the battery pack or by an external source (e.g., the ship's 12V circuit).

[0178] Generally, while two heat exchangers are ideal for a battery pack according to the invention, this number can be adapted according to the desired number of cells, and / or the required cooling capacity. Similarly, in order to best adapt the circulation circuit, the number of pumps can also be increased.

[0179] Figure 6 shows an alternative embodiment of the invention, in which two internal pumps are mounted side by side on the electronic board.

[0180] In this embodiment, a suction line 15 for the internal fluid is provided by an internal pump 13, each line terminating in a filter 15A and also including a check valve (visible but not numbered in these figures). This valve prevents the fluid from being reintroduced into the line when the corresponding pump is off. Finally, each line 15 is configured to be positioned above the pump 13 for which it draws the fluid.

[0181] In order to limit the length of the conduits and maintain good efficiency of the battery block, the delivery conduits 17 are preferably partially fused, allowing for a single inlet of the internal fluid into the first heat exchanger 19A. The remainder of the internal fluid circulation circuit is similar to the internal circulation circuit described in Figures 1 to 5; however, it is more efficient because the two internal pumps 13 act more effectively to move the internal fluid.

[0182] The invention also relates to a watercraft for the transport of persons or goods, this watercraft comprising several BB battery packs with thermal management by immersion. Each pack comprises the internal and external cooling circuits described above, the external heat transfer fluid being fresh water or seawater taken directly from the watercourse or body of water on which the watercraft is navigating.

[0183] The external cooling circuits of the various BB battery packs are partially merged upstream and downstream of said packs in order to limit the number of conduits present in the vehicle. This variant is shown schematically in [Fig. 7]. Advantageously, the battery packs and their corresponding external cooling circuits are mounted in parallel so that their cooling remains equally efficient.

[0184] Thus, a single cold water supply line (UCAE) arrives from outside the vehicle and branches upstream of the BB battery blocks to supply them individually, thereby forming an external CAE supply line for each block. The water is delivered to the BB battery block by means of the external PE pump.

[0185] Similarly, all the external CEE drain pipes exiting each BB battery block merge to form a single external UCEE drain pipe containing the hot water, which returns it to the watercourse or body of water.

[0186] The invention also relates to a method of thermal management by immersion of a battery pack as described above. The method comprises the following steps and will be described in correlation with the preceding Figures 1 to 7.

[0187] First, a first step of sampling the internal fluid from the sealed housing 5 of the battery block BB takes place, this sampling being carried out by the suction conduit 15 of the internal pump(s) 13. Advantageously, the fluid is filtered before being sampled.

[0188] Next, a second stage of sending the internal fluid into the first exchanger 19A takes place, and is carried out via the sending conduit 17.

[0189] Next, a third heat exchange stage is carried out in the first and second exchangers (19A, 19B) between the internal fluid and the external fluid.

[0190] In this step, the internal fluid flows more specifically from the first to the second end (19A.1, 19A.2) of the first heat exchanger 19A. Then, it enters the second heat exchanger 19B through the connecting conduit 21, before flowing through the second heat exchanger 19B from its second to its first end (19B.2, 19B.1). Preferably, the internal fluid also flows through the first and second transfer devices (23A, 23B; 27A, 27B), as described in [Fig. 4].

[0191] The internal fluid is cooled by the external fluid, which enters at the second end 19B.2 of the second heat exchanger 19B, where it flows from its second end to its first end (19B.2, 19B.1). It then passes into the first heat exchanger 19A via the connecting conduit 29 to flow from its first end to its second end (19A.1, 19A.2) before being discharged from the first heat exchanger 19A.

[0192] A fourth stage takes place in which the internal fluid exits the second exchanger 19B through the circulation conduit 25, this conduit extending along the cells 1 of the battery block BB.

[0193] Finally, a fifth step of reinjecting the internal fluid from the orifices of the circulation duct 25 to the cells 1 takes place. This fluid is configured to circulate between, under, and over the cells 1 before being drawn back into the suction duct 15 of the internal pump(s) 13.

[0194] The circulation of the internal fluid ensures efficient cooling or heating of the cells 1. This fluid can also cool the busbars 3, the electronic board(s) 7 and the internal pump(s) 13.

[0195] More specifically, since the external fluid is fresh water or sea water, the circulation of the external fluid also includes the following steps.

[0196] First, water is pumped from the stream or body of water by means of the external PE pump, filtered (the filter not being shown on the diagram) and then sent to the battery block BB by means of the external supply conduit CAE, mounted on said block by means of the inlet fitting 23B.1. At the outlet of the exchangers, the water is discharged by means of the external discharge conduit CEE connected to the outlet fitting 23A.1, this conduit returning it to the stream or body of water.

[0197] Circulating the internal fluid in the two heat exchangers improves its cooling or heating by increasing its surface area for heat exchange with the external heat transfer fluid. Heat exchange is also smoother and more efficient. Overall, improved internal fluid circulation reduces areas where heat dissipation is less efficient, thereby extending cell life and improving the performance and safety of the battery pack.

[0198] The arrangement of the various elements and / or means and / or steps of the invention, in the embodiments described above, should not be understood as requiring such an arrangement in all implementations. In any event, it will be understood that various modifications may be made to these elements and / or means and / or steps, without departing from the spirit and scope of the invention.

[0199] Furthermore, one or more features described only in one embodiment can be combined with one or more other features described only in another embodiment. Similarly, one or more features described only in one embodiment can be generalized to other embodiments, even if this or these features are described only in combination with other features.

[0200] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

Claims

Demands

1. A single-phase thermally managed immersion battery pack (BB) for a watercraft comprising: • A sealed casing (5) containing an internal heat transfer fluid, which casing is delimited by walls, • Cells (1) positioned in the casing (5) and immersed in the internal heat transfer fluid, characterized in that said pack further comprises: • At least one heat exchanger (19A, 19B) for heat exchange between the internal heat transfer fluid and an external heat transfer fluid, which heat exchanger is supported by a wall of the casing, • At least one first pump (13) integrated into the casing for circulating the internal heat transfer fluid in the heat exchanger (19A, 19B), • At least one second pump (PE) configured to pump fresh water or seawater surrounding the vehicle and circulate it in the heat exchanger (19A, 19B), which fresh water or seawater is the fluid external heat transfer fluid.

2. Battery block (BB) according to claim 1, wherein the first pump (13) is positioned inside the sealed housing (5) to be immersed in the internal heat transfer fluid.

3. Battery block (BB) according to any one of claims 1 or 2, in 1e wherein the sealed housing (5) is formed by a casing (5A) closed by a cover (5B).

4. Battery block (BB) according to claims 2 and 3, in which: • the first pump (13) is disposed at one side of the housing (5), • the heat exchanger (19A, 19B) is fixed on the cover (5B) and includes, on the same side as the pump (13), an inlet for the internal heat transfer fluid.

5. Battery pack (BB) according to claim 4, wherein: • a suction conduit (15) of the first pump (13) is positioned near an upper face (IB) of the adjacent cell (1), and • a circulation conduit (25) extends from an outlet of the exchanger (19A, 19B) and is positioned in a bottom (5A.3) of the housing (5A).

6. Battery block (BB) according to claims 4 and 5, wherein an internal circulation circuit of said block is configured to permit the circulation of the internal heat transfer fluid: • From the first pump (13) to the heat exchanger (19A, 19B) via a delivery conduit (17), • from the inlet to the outlet of the heat exchanger (19A, 19B), then • from the circulation conduit (25) connected to the outlet of the heat exchanger (19A, 19B) to the cells (1) of the battery block (BB) in order to permit its reinjection into the sealed housing (5).

7. Battery block (BB) according to any one of claims 5 or 6, wherein the housing (5A) comprises at least one partition (5A.1) and a space arranged between said partition and the adjacent cells (1), this space receiving: • the circulation conduit (25) comprising orifices, each orifice being positioned between two adjacent cells (1); and • partitioning elements (9), each of these elements extending between one of the cells (1) and the adjacent partition (5A.1) so as to form a sealed separation between two adjacent cells (1), each element being positioned vertically from the bottom (5A.3) of the housing (5A) to the upper face (IB) of the corresponding cell, each element partitioning the space arranged so as to force the internal heat transfer fluid to circulate from the circulation conduit (25) between, below, and above the cells (1).

8. Battery block (BB) according to any one of claims 4 to 7, wherein an external circulation circuit is configured to permit the circulation of the external heat transfer fluid, the circulation of said fluid being carried out from: • a watercourse or body of water via an external supply duct (CAE) to • an inlet of said fluid in the exchanger (19A, 19B), positioned at the opposite end of the inlet of the internal heat transfer fluid, to • an outlet of the exchanger (19A, 19B) positioned on the side of the inlet of the internal heat transfer fluid so that the external heat transfer fluid is evacuated from the exchanger (19A, 19B) via an external discharge duct (CEE), and to • be returned to the watercourse or body of water, the circulation being carried out by means of the second pump (PE).

9. Battery block (BB) according to any one of the preceding claims, wherein: • a cover (19A.3, 19B.3) is installed around the exchanger (19A, 19B), and • the exchanger (19A, 19B) is a plate exchanger comprising between 6 and 10 plates.

10. Battery block (BB) according to claims 3 and 9, wherein the fixing of the exchanger (19A, 19B) on the cover (5B) is made at a distance between 2 mm and 6 mm so as to free up a passage between the cover (5B) and the exchanger (19A, 19B).

11. Battery block (BB) according to any one of claims 5 to 10, wherein each cell (1) is positioned on a support (5A.4) so ​​as to be at a distance from the bottom (5A.3) of the casing (5A) to allow circulation of the internal heat transfer fluid under each cell.

12. Battery block (BB) according to claims 4 and 5 in combination with any one of claims 6 to 11, wherein: • two heat exchangers (19A, 19B) are fixed side by side on the cover (5B); • the inlet of the internal heat transfer fluid is positioned on a first heat exchanger (19A) and the outlet of said fluid is positioned on a second heat exchanger (19B), said inlet and outlet being located at first extremities (19A.1, 19B.1) of the exchangers (19A, 19B) oriented towards the side of the pump (13); and • a connecting conduit (21) connects the second ends (19A.2, 19B.2) of the exchangers (19A, 19B), positioned opposite the said first ends (19A.1, 19B.1).

13. Battery block (BB) according to claims 6 and 12, wherein the internal circulation circuit is configured to permit the circulation of the internal heat transfer fluid between the two heat exchangers (19A, 19B): • From the first to the second end (19A.1, 19A.2) of the first heat exchanger (19A), then • From the first to the second heat exchanger (19A, 19B) via the connecting conduit (21), and • From the second to the first end (19B.2, 19B.1) of the second heat exchanger (19B), before its reinjection into the sealed casing (5) via the circulation conduit (25).

14. Battery block (BB) according to claims 8 and 12, wherein the external circulation circuit is configured to permit the circulation of the external heat transfer fluid between the two exchangers (19A, 19B): • From the second to the first end (19B.2, 19B.1) of the second exchanger (19B), then • From the second to the first exchanger (19B, 19A) through a connecting conduit (29), and • From the first to the second end (19A.1, 19A.2) of the first exchanger (19A) before its discharge to the watercourse or body of water.

15. Battery block (BB) according to any one of claims 2 to 14, wherein the first pump (13) is mounted on an electronic board (7) comprising a control system for the battery block (BB), said board extending vertically in the sealed housing (5) and parallel to the cells (1) to be immersed in the internal heat transfer fluid, the control system for the battery block (BB) being configured to control the operation of the first and second pumps (13, PE) at the housing (5).

16. Battery pack (BB) according to claim 15, comprising: • at least one internal heat transfer fluid pressure sensor, and / or • a level sensor for said fluid, said sensors being mounted on the electronic board (7), controlled by the battery block control system (BB) and immersed in the internal heat transfer fluid.

17. Battery block (BB) according to any one of claims 15 or 16, wherein one end of the cover (5B) comprises: • power connectors (5B.1); and / or • control connectors (5B.2) of the battery block (BB) control system preferably mounted on a connector housing (5B.3), all of said connectors (5B.1, 5B.2) being partially immersed in the internal heat transfer fluid and positioned at a distance from the battery block (BB) control system.

18. Battery block (BB) according to claim 8 in combination with any one of claims 15 to 17, wherein at least two temperature sensors are installed in the battery block and controlled by the control system of said block, including a first sensor positioned at the inlet of the external circulation circuit and a second sensor positioned at the outlet of said circuit.

19. Battery block (BB) according to any one of the preceding claims, wherein the cells (1) of the battery block (BB) are sodium-ion cells (1) connected together by busbars (3) immersed in the internal heat transfer fluid.

20. Battery block (BB) according to any one of claims 15 to 19, wherein two first pumps (13) are immersed and mounted side-by-side on the electronic board (7) comprising the control system of the battery block (BB), each pump (13) comprising a suction conduit (15) with a non-return valve, this conduit being terminated by a filter (15A).

21. A watercraft for the transport of persons or goods comprising several immersion-controlled thermally managed battery packs (BBs), characterized in that each battery pack (BB) is according to any one of claims 1 to 20, and Each battery block (BB) includes an external circulation circuit using fresh water or seawater, all of said circuits being partially merged upstream and downstream of the battery blocks (BB) and being mounted in parallel such that: • A single external cold water supply line (UCAE) enters from outside the watercraft and branches upstream of the battery packs (BB) to supply them individually, and • External discharge conduits (CEE) exiting the battery blocks (BB) merge to form a single external discharge conduit (UCEE) containing the hot water, and returning this water to the stream or body of water.

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