Battery module featuring spacers, battery and associated vehicle

Abstract

Battery module with interlayer pieces, battery, and associated vehicle. This module comprises a stack including: * a plurality of electrochemical cells (18); * at least one interlayer piece (20) interposed between each pair of adjacent cells (18); * a stack retention mechanism clamping the cells (18) and the interlayer pieces (20) together; The module includes at least one dielectric coolant for the stack. The interlayer piece (20) defines at least one open channel (82A, 82B) for the circulation of the dielectric coolant. The channel (82A, 82B) opens at the periphery of the stack to allow the circulation of the dielectric fluid within the stack and opens opposite a main face (74, 76) of at least one cell (18) applied to the interlayer piece (20), to bring the main face (74, 76) into contact with the dielectric fluid. (See Figure 2 for abbreviations)

Description

Title of the invention: Battery module featuring interlayer parts, battery and associated vehicle

[0001] The present invention relates to a battery module comprising:

[0002] - a case defining an internal volume;

[0003] - a stack comprising;

[0004] * a plurality of electrochemical cells stacked in the internal volume;

[0005] * at least one interposed intermediary piece between each pair of electro-cells adjacent chemicals;

[0006] * a stacking retention mechanism designed to clamp the electro-cells chemical and intercalated parts against each other; the stack being contained within the internal volume;

[0007] - at least one dielectric liquid for cooling the stack.

[0008] Such a module is intended for use in particular in electrical power supply applications in the automotive, aerospace, and / or energy storage sectors. Such a module is particularly suited to high electrical power applications.

[0009] The ecological transition requires the use of batteries in which the electrical powers involved are increasingly higher, both when supplying a current and a voltage to a consumer system, or when recharging the battery module.

[0010] In this context, a battery module of the aforementioned type generally undergoes significant heating which requires efficient dissipation of the calories produced by Joule effect.

[0011] Furthermore, when the battery module contains cells, particularly lithium-ion cells, made of flexible casings (called pouches) or rigid prismatic casings, these tend to swell, especially during battery module charging. It is therefore necessary to ensure adequate mechanical strength of the battery module and the electrochemical cells during use.

[0012] To solve the aforementioned problems, US 2016 / 0164061 proposes a solution in which electrochemical cells are stacked one on top of the other with the interposition, between each pair of adjacent cells, of a heat dissipation plate.

[0013] The plate has lateral fins that protrude transversely from the stack. It transfers the heat produced in the The cells are directed towards the fins. Furthermore, a duct through which a coolant circulates passes. Thus, the heat present in the fins is transferred outside the battery module via the coolant.

[0014] Such a battery module does not, however, give complete satisfaction.

[0015] Firstly, heat exchange by conduction only allows limited heat dissipation, which can cause problems in certain high-power applications.

[0016] Moreover, the module equipped with the dissipation plates is heavy and bulky, particularly due to the presence of the fins, which is a major drawback for embedded applications such as in the automotive, space or aeronautical sectors.

[0017] An object of the invention is therefore to provide a battery module in which the calories generated during the delivery of electrical power, or during the recharging of the module, are dissipated very efficiently, the module remaining compact and mechanically integrated, and adaptable to various connectors.

[0018] To this end, the invention relates to a battery module of the aforementioned type, characterized in that the dielectric liquid fills the internal volume, the stack being totally immersed in the dielectric liquid,

[0019] the or each interlayer piece defining at least one open channel for the circulation of the dielectric liquid, the open channel for the circulation of the dielectric liquid opening at the periphery of the stack to allow the circulation of the dielectric liquid in the stack and opening opposite a main face of at least one electrochemical cell applied to the interlayer piece, to bring the main face of the electrochemical cell into contact with the dielectric liquid.

[0020] The battery module according to the invention may comprise one or more of the following features, taken individually or in any technically feasible combination(s):

[0021] - at least one intercalated piece defines a plurality of open channels of circumference culation of the dielectric liquid separated from each other;

[0022] - the or each intercalated piece defines at least one first open channel of circumference circulation of the dielectric liquid opening towards a first main face of a first electrochemical cell adjacent to the intercalated piece, and closed towards a second main face of a second electrochemical cell adjacent to the intercalated piece, located opposite the first electrochemical cell with respect to the intercalated piece, the intercalated piece comprising at least a second open channel for circulation of the dielectric liquid opening towards the second main face of the second electrochemical cell, and closed towards the first main face of the first electrochemical cell;

[0023] - a bottom of the first open channel for circulating the dielectric liquid is applied on the second main face of the second electrochemical cell, a bottom of the second open channel for circulating the dielectric liquid being applied to the first main face of the first electrochemical cell;

[0024] - the open channel for circulating the dielectric liquid opens at the periphery of stacking through at least two distinct openings;

[0025] - the two separate openings lead into two separate faces of stacking, advantageously in two opposite or adjacent faces of the stack, or the two distinct openings lead into the same face of the stack;

[0026] - the cross-sectional area of ​​each open liquid circulation channel electrical is less than 2 mm2, and in particular between 0.5 mm2 and 2 mm2;

[0027] - the housing defines an inlet for supplying dielectric liquid into the volume interior and a dielectric fluid discharge outlet outside the interior volume, the inlet and outlet being intended to be connected to a dielectric fluid cooling circuit advantageously comprising a pump;

[0028] - the retaining mechanism comprises two end flanges, arranged on either side and on the other side of the stacking, and at least one tie connecting the two end flanges;

[0029] - at least one of the end flanges has an inner face intended to be placed opposite an electrochemical cell of the stack, the inner face being curved before clamping the stack with the tie rod and flattening onto a main face of an electrochemical cell after clamping the stack with the tie rod;

[0030] - the housing has a side access opening and an opposite internal face located with regard to the side access opening, the retaining mechanism comprising at least one closing hatch for the side access opening designed to compress the stack between the hatch and the opposite face;

[0031] - each electrochemical cell defines at least one connection tab electrical protruding from the stack, the electrical connection tabs being immersed in the dielectric liquid;

[0032] - the battery module includes at least one connection system and / or to less an electronic battery module management system connected to each electrical connection tab, the connection system and / or the electronic management system being immersed in the dielectric liquid;

[0033] - each electrochemical cell comprises a pocket, in particular is a cell pocket-sized lithium-ion electrochemical cell, or in which each electro-cell chemical comprises a prismatic element, the dielectric liquid present in the or each open channel of dielectric liquid circulation being in contact with the pocket or prismatic element.

[0034] The invention also relates to a battery comprising at least one battery module as defined above, in particular several battery modules as defined above.

[0035] The battery advantageously includes a dielectric liquid cooling circuit, connected to the battery module, supplying the or each open channel of dielectric liquid circulation.

[0036] The invention also relates to a vehicle, in particular a motor vehicle, space vehicle or aircraft, comprising a battery as defined above.

[0037] The invention also relates to a method for generating electrical power from a battery module or for recharging a battery module, comprising the following steps:

[0038] - supply of a battery module as defined above;

[0039] - generation of electrical power from the electrochemical cells of the module battery, or recharging of electrochemical cells from an external electrical power source;

[0040] - during the generation of electrical power or recharging, putting into circulation dielectric liquid through the open channel or each dielectric liquid circulation channel to dissipate by convection on at least one main face the calories produced by the electrochemical cells.

[0041] The invention will be better understood upon reading the following description, given solely by way of example, and made with reference to the accompanying drawings, in which:

[0042] - [Fig. 1] [Fig. 1] is an exploded perspective view of a first module of battery according to the invention;

[0043] - [Fig.2] [Fig.2] is an exploded perspective view of a stack of the module of battery of the [Fig.l], comprising two electrochemical cells, separated by an intercalated piece defining open channels;

[0044] - [Fig.3] Fig.3 is a cross-sectional view taken along a longitudinal axial plane, of a detail of the stacking contained in the module of [Fig.1];

[0045] - [Fig.4] [Fig.4] is an exploded perspective view of the stack contained in the battery module of [Fig.1];

[0046] - [Fig. 5] [Fig. 5] is a cross-sectional view taken along a horizontal plane of the flanges of the ends of the stack of [Fig.4], (a) before tightening the clamping mechanism and (b) after tightening the retaining mechanism;

[0047] - [Fig.6] Fig.6 is a view illustrating an intercalary piece of a second battery module according to the invention, and next to the intercalated piece, the representation schematic of the flow of liquid circulating through the intercalated piece;

[0048] - [Fig.7] [Fig.7] is a view analogous to [Fig.6], for a third module of battery according to the invention;

[0049] - [Fig.8] [Fig.8] is a view analogous to [Fig.6] for a fourth module of battery according to the invention;

[0050] - [Fig.9] The [Fig.9] is a schematic side view of a fifth module of battery according to the invention.

[0051] A first battery module 10 according to the invention is schematically illustrated in Figures 1 to 5. The battery module 10 is intended to be integrated into a battery system (not shown) comprising one or more identical battery modules 10.

[0052] The battery module 10 comprises a housing 12, defining an internal volume 14. It further comprises a stack 16 received in the inner volume 14, the stack 16 comprising a plurality of electrochemical cells 18, spacers 20 separating each pair of adjacent electrochemical cells 18, and a retaining mechanism 22 for the electrochemical cells 18 and the spacers 20.

[0053] The battery module 10 further includes a connection system 24 for connecting the electrochemical cells 18 to terminals 26 and an electronic battery management system 28, the connection system 24 and the electronic management system 28 also being arranged in the internal volume 14.

[0054] The internal volume 14 of the housing 12 is further filled with a dielectric liquid 30, in which the stack 16, the connection system 24, the terminals 26, and the electronic management system 28 are immersed.

[0055] The battery module 10 is connected to a cooling circuit 32 ensuring the circulation of the dielectric liquid in the internal volume 14 and the evacuation of the heat it contains, outside the battery module 10.

[0056] With reference to [Fig. 1], the housing 12 has a base 40, and side walls 42 projecting out from the base 40.

[0057] In this example, the case 12 has four side walls 42 perpendicular in pairs defining between themselves and with the bottom 40, the internal volume 14.

[0058] The side walls 42 further define a top opening 44 for access to the interior volume 14.

[0059] The housing 12 further includes a cover 46 suitable for removably closing the access opening 44 in order to allow the loading of the stack 16 into the internal volume 14 and its possible unloading.

[0060] The housing 12 further defines an inlet 48 for supplying dielectric fluid into the internal volume 14 and an outlet 50 for draining dielectric fluid out of the internal volume 14. The inlet 48 and the outlet 50 are each connected to the cooling circuit 32.

[0061] In the example shown in [Fig.1], the supply inlet 48 is located near the bottom 40, on a side wall 42. The evacuation outlet 50 is located near the access opening 44, on a side wall 42 opposite to the one where the supply inlet 48 is located.

[0062] In this example, the stack 16 extends along an axis A-A' parallel to the bottom 40 of the internal volume 14 of the housing 12 when the stack 16 is received in the internal volume 14.

[0063] The stack 16 comprises more than five electrochemical cells 18, preferably between 5 and 20 electrochemical cells 18 stacked against each other with interposition of an intercalary piece 20 between each pair of adjacent electrochemical cells 18.

[0064] In this example, each electrochemical cell 18 comprises an outer envelope or pocket 60 containing a plurality of electrodes (not shown) of opposite polarities, arranged in the pocket 60 and separated from each other by an internal separator (not shown).

[0065] The flexible pouch or bag 60 is advantageously formed by welding the edges of two multilayer films, each multilayer film comprising a metallic layer, generally aluminum, sandwiched between two layers of plastic material. The pouch thus formed is filled with electrodes of opposite polarities separated by an internal separator, with an electrolyte, and then sealed airtight.

[0066] Pocket 60 is advantageously deformable to the touch.

[0067] Alternatively, the electrochemical cell 18 comprises a prismatic-shaped envelope containing electrodes of opposite polarities. The prismatic element is non-deformable under touch.

[0068] In a non-limiting example, the electrochemical cell 18 is a lithium-ion electrochemical cell.

[0069] Each electrochemical cell 18 further comprises at least one electrical connection tab 62 to the positive polarity electrodes, and at least one electrical connection tab 64 to the negative polarity electrodes. In the example shown in [Fig. 2], the electrochemical cell 18 further comprises a support frame 68 defining electrical connection plates 70 located between the pocket 60 and the tabs 62, 64.

[0070] The frame 68 further includes lateral supports defining lateral edges 72A, 72B of the electrochemical cell 18.

[0071] Each flexible outer pocket 60 has a first main face 74, and a second main face 76 located opposite face 74. The main faces 74, 76 extend perpendicularly to the axis A-A', and perpendicularly to the bottom 40 of the case 12, when the stack 16 is received in the inner volume.

[0072] The main faces 74, 76 extend to the lateral edges 72A, 72B of the electrochemical cell 18. They extend between a lower edge 72C of the electrochemical cell 18 and the stiffening plates 70 under the tabs 62, 64.

[0073] Each interlayer piece 20 is interposed between a pair of adjacent electrochemical cells 18. Each interlayer piece 20 comprises in this example a lower region 80 provided with open channels 82A, 82B and, between the channels 82A, 82B, support zones 83A, 83B for the interlayer piece 20 on a respective face 74, 76 of an electrochemical cell 18.

[0074] Each interleaf piece 20 here further comprises an upper region 84 for separating the tabs 62, 64 of the successive cells 18.

[0075] Each intercalary piece 20 further advantageously includes lateral tabs 86, projecting laterally on either side of the intercalary piece 20, beyond the lateral edges 72A, 72B of the electrochemical cells 18 for guiding the retaining mechanism 22.

[0076] The spacer pieces 20 are preferably made of plastic, for example polyamide (in particular PA66, PA12, PA12GF30).

[0077] In the example shown in Figures 2 and 3, the channels 82A, 82B and the support areas 83A, 83B are defined by a plurality of adjacent hollow ribs. Each hollow rib internally delimits an open channel 82A opening towards a first main face 74 of a first electrochemical cell 18 of the battery. The adjacent ribs delimit between themselves second channels 82B opening opposite a second face 76 of a second electrochemical cell 18 adjacent to the first electrochemical cell 18.

[0078] With reference to [Fig.3], each channel 82A opening opposite a first main face 74 is laterally delimited (here horizontally upwards and downwards) by two lateral partitions 90C, 90D which are common with adjacent channels 82B.

[0079] Each channel 82A is further delimited by a bottom 92A which defines a support area 83A on the second main face 76. In this example, the bottom 92A of the channel 82A connects the side partitions 90C, 90D.

[0080] Similarly, each channel 82B opening opposite a second main face 76 is delimited laterally (here horizontally upwards and downwards) by two lateral partitions 90C, 90D which are common with adjacent channels 82A.

[0081] Each channel 82B is further delimited by a bottom 92B which defines a support area 83B on the first main face 74. In this example, the bottom 92B of the channel 82B connects the side partitions 90C, 90D.

[0082] Each channel 82A, 82B opens respectively opposite a respective face 74, 76 of a respective cell 18 by a longitudinal opening 87A, 87B extending over the entire length of the channel 82A, 82B.

[0083] As can be seen in [Fig.2], each channel 82A, 82B also opens at its ends by at least a first lateral opening 88C and by a second lateral opening 88D which in this example open into opposite lateral faces of the stack 16, on either side of the axis A-A'.

[0084] Each longitudinal opening 87A, 87B of a channel 82A, 82B is located opposite the respective bottom 92A, 92B of the channel 82A, 82B opposite a respective main face 74, 76 of an electrochemical cell 18.

[0085] Advantageously, the channels 82A, 82B are all disjoint. Thus, no channel 82A, 82B opens into another channel 82A, 82B, or communicates with another channel 82A, 82B. The channels 82A, 82B thus define separate paths for the circulation of the dielectric fluid.

[0086] In this example, channels 82A and 82B are all parallel to each other and parallel to the bottom 40 of housing 12. Other examples of channel 82A and 82B configurations will be described below.

[0087] Each channel 82A, 82B preferably has a cross-section for the circulation of the dielectric liquid 30, with an area greater than 0.5 mm2, and preferably less than 5 mm2. This cross-section is in particular between 1 mm2 and 2 mm2.

[0088] The depth of each channel 82A, 82B, taken along the axis A-A' between the bottom 92A, 92B and the longitudinal opening 87A, 87B is preferably between 0.5 and 2 times the thickness of the bottom 92A, 92B.

[0089] The number of channels 82A, 82B on each face of the interlayer piece 20 is for example greater than 5, in particular greater than 10. It depends on the size of the electrochemical cell 18.

[0090] The side partitions 90C, 90D generally have a thickness between 0.5 mm and 1 mm.

[0091] The thickness of the intercalated piece 20, taken along the axis A-A', remains less than the thickness of each adjacent electrochemical cell 18.

[0092] Preferably, the ratio of the total area of ​​the bearing zones 83A, 83B to the total area of ​​the longitudinal openings 87A, 87B of the channels 82A, 82B on each face 74, 76 is generally between 20% and 80%, in particular between 40% and 60%. This ensures both broad exposure of the main faces 74, 76 to direct contact with the dielectric liquid 30 and structural robustness of the interlayer piece 20 to resist deformation, in particular swelling of the electrochemical cells 18.

[0093] The upper region 84 is devoid of channels 82A, 82B. It extends opposite the connecting tabs 62, 64, and the stiffening plates 70.

[0094] The length of each channel 82A, 82B taken linearly between the lateral openings 88C, 88D is greater than its width, in particular 10 times its width, the width being taken at the level of the longitudinal opening 87A, 87B,

[0095] With reference to figures 4 and 5, the retaining mechanism 22 comprises two end flanges 100A, 100B arranged on either side of the stack 16 of electrochemical cells 18 and intercalated pieces 20.

[0096] The retaining mechanism 22 further includes tie rods 102, intended to clamp the stack 16 of electrochemical cells 18 and spacer pieces 20 between the end flanges 100A, 100B.

[0097] The flanges 100A, 100B are arranged opposite two electrochemical cells 18 located at the axial ends of the stack 16 of electrochemical cells 18 and intercalated pieces 20 along the axis A-A'.

[0098] Each flange 100A, 100B has an inner face 104 intended to be placed opposite a main face 74, 76 of an electrochemical cell 18A, 18B and an outer face 106, intended to cooperate with the tie rods 102. It also has guide lugs 108 for the tie rods 102, which protrude laterally from the outer face 106.

[0099] As illustrated by [Fig.4], the inner face 104 of each end flange 100A, 100B defines open channels 82A, 82B intended to open opposite the main face 74, 76 opposite which the flange 100A, 100B is placed.

[0100] The channels 82A, 82B each have a structure identical to those described above for each interlayer piece 20.

[0101] As illustrated by [Fig.5](a), in section in a horizontal plane parallel to the bottom 40 of the housing 12, the inner face 104 of each end flange 100A, 100B has at rest an inner contour curved towards the main face 74, 76, before the installation of the tie rods 102.

[0102] Once the tie rods 102 are mounted to clamp the electrochemical cells 18 and the spacer pieces 20 interposed between the flanges 100A, 100B, the flanges 100A, 100B are deformable, so that in cross-section in the horizontal plane parallel to the bottom 40 of the housing 12, the inner face 104 is flat and applies itself against the main face 74, 76 of the electrochemical cell 18A, 18B. This ensures homogeneous contact between each end flange 100A, 100B and the electrochemical cell 18A, 18B opposite which it is placed.

[0103] To ensure such deformation, the flanges 100A, 100B are preferably made of plastic, in particular polyphenylene sulfide (PPS), or alternatively, of metal, in particular aluminum.

[0104] The outer face 106 of each flange 100A, 100B is provided with horizontal locking grooves 110, into which each tie rod 102 is inserted.

[0105] As illustrated by [Fig.4], each tie rod 102 here comprises a first stirrup 112A intended to be placed on one side of the stack 16, opposite the first flange 100A, and a second stirrup 112B intended to be placed on the other side of the stack 16, opposite the second flange 100B.

[0106] The stirrups 112A, 112B each have a C shape with free ends 114A, 114B. They are provided with a means of fixing the ends 114A, 114B together, for example a screw mechanism which allows adjustment of the distance between the flanges 100A, 100B, and therefore the clamping of the stack 16.

[0107] In an alternative (not shown), the 102 tie rods are straight and not U-shaped.

[0108] With reference to [Fig. 1], the connection system 24 is intended to electrically connect the tabs 62, 64 to the terminals 26, via the electronic control system 28, when the latter is present. The connection system 24 and the electronic control system 28 are located above the stack 16 under the cover 46, in the internal volume 14.

[0109] The connection system 24 includes electrical connections. In the example shown in [Fig.1], it includes an insulating piece which covers the electrical connections and integrates a connector part for measuring the individual voltages of each electrochemical cell.

[0110] The electronic management system 28 includes electronic components for controlling the voltage and / or current delivered by the battery module 10 during its discharge, and the voltage and / or current received by the battery module 10 during its recharge.

[0111] The entire stack 16, including the electrochemical cells 18, the interlayer pieces 20 and the retaining mechanism 22, is immersed in the dielectric liquid 30. The connection system 24 and the electronic management system 28 are also advantageously totally immersed in the dielectric liquid 30.

[0112] The dielectric liquid 30 fills in particular the channels 82A, 82B located between the electrochemical cells 18, and comes into direct contact with the main faces 74, 76 of the electrochemical cells 18 through the longitudinal openings 87A, 87B.

[0113] Thus, a heat exchange by convection occurs directly at the level of each main face 74, 76 of each electrochemical cell 18, between the dielectric liquid 30 and the electrochemical cell 18, allowing the very efficient evacuation of the heat generated in the electrochemical cell 18.

[0114] Preferably, the dielectric liquid 30 is circulated in the internal volume 14 by means of a pump in the cooling circuit 32.

[0115] Dielectric liquid 30 intended to be heated is conveyed into the internal volume 14 through the inlet 48, to circulate from bottom to top and laterally from the inlet 48 to the outlet 50 through the channels 82A, 82B.

[0116] The dielectric liquid 30 thus enters each channel 82A, 82B through a first end opening 88C, sweeps across a main face 74, 76 along the longitudinal opening 87A, 87B where it heats up, and exits the stack 16 through a second end opening 88D, before reaching the discharge outlet 50.

[0117] The dielectric liquid 30 advantageously has a resistivity greater than 50 GQ and a breaking voltage greater than 40 kV for an air gap of 2.5 mm, preferably between 45 kV and 55 kV for an air gap of 2.5 mm.

[0118] The dielectric liquid 30 furthermore has a density less than 1, for example between 0.7 and 0.9, and a low viscosity, for example less than 3.3 mPa.s at 25°C, as measured by ASTM Standard D7042.

[0119] The assembly of the battery module 10 is particularly simple to carry out.

[0120] The electrochemical cells 18 and the spacer pieces 20 are provided and are mounted alternately against each other, each spacer piece 20 being inserted between two adjacent electrochemical cells 18. Then, end flanges 100A, 100B are placed at the ends of the stack 16. The stirrups 112A, 112B are then inserted into the grooves 110 in contact with the outer face 106 of each end flange 100A, 100B.

[0121] The stirrups 112A, 112B are inserted into the tabs 86, 108 on either side of the intermediate pieces 20 and the flanges 100A, 100B.

[0122] The free ends 114A, 114B of the stirrups 112 are then joined together, and a clamping force is applied so that the tie rods 102 maintain the stack 16 in compression.

[0123] The connection system 24 and the electronic management system 28 are then mounted on the stack 16.

[0124] Then, the stack 16 is introduced into the inner volume 14 of the housing 12 through the upper opening 44. The cover 46 is then put in place to close the upper opening 44.

[0125] The internal volume 14 of the battery module 10 is then filled with coolant 30 and is connected to the cooling circuit 32.

[0126] During operation, during a discharge phase of the battery module 10, a current and a voltage are delivered through the terminals 26 of the battery module 10. Conversely, during a charging phase, a current and a voltage are applied to the terminals 26 of the battery module 10.

[0127] The heat generated in the electrochemical cells 18 is dissipated by circulating the dielectric liquid 30 from the supply inlet 48, in the internal volume 14 around the stack 16, through the first end openings 88C of the channels 82A, 82B and then along the channels 82A, 82B in contact with the faces main 74, 76 of the electrochemical cells 18.

[0128] The dielectric liquid 30 then heats up by convection, and is evacuated through the second end openings 88D, then through the liquid evacuation outlet before being cooled in the circuit 32.

[0129] The shape of the channels 82A, 82B delimited by the intercalated pieces 20 ensures an appropriate flow of dielectric liquid 30 in contact with the faces 74, 76 of the electrochemical cells 18, while allowing the intercalated pieces 20 to maintain excellent mechanical contact with the electrochemical cells 18.

[0130] The presence of the support zones 83A, 83B prevents the electrochemical cells 18 from swelling and maintains the integrity of the stack 16, even under high power delivery and / or during charging. The reduced dimensions of the channels 82A, 82B compared to the volume outside the channels 82A, 82B further accelerate the flow of dielectric fluid 30 within the channels 82A, 82B, thereby increasing the heat exchanged within the channels 82A, 82B and thus the cooling capacity within the battery module 10.

[0131] The circulation of a dielectric liquid 30 as defined above further ensures that the battery module 10 is reliable and safe, while also providing high cooling performance. This performance is due in particular to direct convection from the electrochemical cells 18 to the dielectric liquid 30.

[0132] In addition, the dielectric liquid 30 filling the entire internal volume 14, it cools the various connection tabs 62 and 64 of each electrochemical cell 18 and the electronic management system 28 which are immersed.

[0133] The advantageous properties stated above in terms of cooling, mechanical robustness, reliability and safety are obtained while maintaining maximum compactness of the battery module 10, in particular compared to existing solutions.

[0134] This is the case in relation to conventional exchangers, which are interposed between electrochemical cells, but in which the heat exchange between the coolant and the cell wall takes place solely by thermal conduction without contact.

[0135] Furthermore, since the stack 16 is totally immersed in the internal volume 14, it is not necessary to provide a storage capacity for dielectric liquid 30, the internal volume 14 constituting this storage capacity.

[0136] The mass and volume gain compared to a conventional battery module can therefore be in the order of 30% to 50%, particularly when the intercalated parts 20 are made of plastic.

[0137] In addition, the configuration of channels 82A, 82B is modifiable to adapt to various positions of the supply inlets 48 and the evacuation outlets 50.

[0138] In the example of [Fig.6], the liquid inlet 48 is located at the bottom of the housing 12. The liquid outlet 50 is located in the cover 46.

[0139] In this case, the channels 82A, 82B extend vertically, perpendicular to the axis A-A' and to the bottom 40. The first openings 88C open into a lower face of the stack 16, while the second openings 88D open into a higher face of the stack 16. The interlayer pieces 20 of [Fig.6] further differ from those of [Fig.2] in that the upper region 84 is also provided with channels 82A, 82B.

[0140] In the variant shown in [Fig.7], the liquid inlet 48 and the liquid outlet 50 are located on the same lateral wall 42, on the same side of the housing 12.

[0141] In this case, the first openings 88C and the openings 88D open into the same lateral face of the stack 16. Each channel then has a U shape with a half turn opposite the openings 88C, 88D.

[0142] In the example shown in [Fig. 7], the channels 82A, 82B further adopt a nested configuration with the outermost channel 82A, 82B having the outermost openings 88C, 88D and a U-shape of maximum width. The outermost channel 82A, 82B contains all the channels 82A, 82B having a U-shape of smaller width, each channel 82A, 82B having a U-shape of smaller width being nested within a channel 82A, 82B having a U-shape of larger width.

[0143] The variant of [Fig.8] differs from that of [Fig.7] in that the supply inlet 48 and the discharge outlet 50 open into the bottom 40.

[0144] The end openings 88C, 88D of each channel 82A, 82B all open into a lower face of the stack 16.

[0145] Each channel 82A, 82B also has a U shape, with channels 82A, 82B advantageously in a nested configuration, as described previously.

[0146] In another variant shown in [Fig.9], the housing 12 is provided with a top wall 42A fixed relative to the side walls 42.

[0147] The side walls 42 define a lateral access opening 44 to the interior volume in a lateral face of the housing 12.

[0148] In this example, the retaining mechanism 22 is without a tie rod 102. The first flange 100A is formed by the inner face of a side wall 42. The second flange 100B is formed by a hatch 120, suitable for closing the access opening 44, by compressing the electrochemical cells 18 and the intercalated pieces 20 against each other to hold them in contact with the flange 100A.

[0149] This variant further reduces the number of parts required to achieve the 16-piece stacking, increases compactness, while retaining the advanced properties. tagers described above.

Claims

Demands

1. Battery module (10) comprising: - a housing (12) defining an internal volume (14); - a stack (16) comprising: * a plurality of electrochemical cells (18) stacked in the internal volume (14), each electrochemical cell (18) defining at least one electrical connection tab (62, 64) projecting from the stack (16); * at least one spacer piece (20) interposed between each pair of adjacent electrochemical cells (18); * a stack retention mechanism (22) adapted to clamp the electrochemical cells (18) and the spacers (20) together; the stack (16) being contained within the internal volume (14);- at least one dielectric liquid (30) for cooling the stack (16), characterized in that the dielectric liquid (30) fills the internal volume (14), the stack (16) being totally immersed in the dielectric liquid (30), the interlayer piece(s) (20) defining at least one open channel (82A, 82B) for the circulation of the dielectric liquid, the open channel (82A, 82B) for the circulation of the dielectric liquid opening at the periphery of the stack (16) to allow the circulation of the dielectric liquid (30) within the stack (16) and opening opposite a main face (74, 76) of at least one electrochemical cell (18) applied to the interlayer piece (20), to bring the main face (74, 76) of the electrochemical cell (18) into contact with the dielectric liquid (30), the interlayer piece(s) (20) further comprising a upper region (84) of separation of the tabs (62, 64) of successive cells (18).;

2. Battery module (10) according to claim 1, wherein at least one interlayer piece (20) defines a plurality of open channels (82A, 82B) for the circulation of dielectric liquid separated from each other.

3. Battery module (10) according to claim 2, wherein the interlayer piece or pieces (20) define at least one first open channel (82A) for the circulation of the dielectric liquid opening towards a first main face (74) of a first electrochemical cell (18) adjacent to the intercalated piece (20), and closed towards a second main face (76) of a second electrochemical cell (18) adjacent to the intercalated piece (20), located opposite the first electrochemical cell (18) with respect to the intercalated piece (20), the intercalated piece (20) comprising at least one second open channel (82B) for the circulation of the dielectric liquid opening towards the second main face (76) of the second electrochemical cell (18), and closed towards the first main face (74) of the first electrochemical cell (18).

4. Battery module (10) according to claim 3, wherein a bottom (92A) of the first open channel (82A) of dielectric fluid circulation is applied to the second main face (76) of the second electrochemical cell (18), a bottom (92B) of the second open channel (82B) of dielectric fluid circulation being applied to the first main face (74) of the first electrochemical cell (18).

5. Battery module (10) according to any one of the preceding claims, wherein the open channel (82A, 82B) for circulating the dielectric liquid opens at the periphery of the stack (16) through at least two separate openings (88C, 88D).

6. Battery module (10) according to claim 5, wherein the two separate openings (88C, 88D) open into two separate faces of the stack (16), advantageously into two opposite or adjacent faces of the stack (16), or wherein the two separate openings (88C, 88D) open into the same face of the stack (16).

7. Battery module (10) according to any one of the preceding claims, wherein the cross-sectional area of ​​each open channel (82A, 82B) for the circulation of the dielectric fluid is less than 2 mm2, and in particular between 0.5 mm2 and 2 mm2.

8. Battery module (10) according to any one of the preceding claims, wherein the housing (12) defines an inlet (48) for supplying dielectric fluid (30) into the inner volume (14) and an outlet (50) for draining dielectric fluid (30) outside the inner volume (14), the inlet (48) and the outlet (50) being intended to be connected to a cooling circuit (32) for the dielectric fluid (30) advantageously comprising a pump.

9. Battery module (10) according to any one of the preceding claims preceding, in which the retaining mechanism (22) comprises two end flanges (100A, 100B), arranged on either side of the stack (16), and at least one tie rod (102) connecting the two end flanges (100A, 100B).

10. Battery module (10) according to claim 9, wherein at least one of the end flanges (100A, 100B) has an inner face (104) intended to be placed opposite an electrochemical cell (18) of the stack (16), the inner face (104) being curved before clamping the stack (16) with the tie rod (102) and flattening onto a main face (74, 76) of an electrochemical cell (18) after clamping the stack (16) with the tie rod (102).

11. Battery module (10) according to any one of claims 1 to 7, wherein the housing (12) has a side access opening (44) and an opposite inner face located opposite the side access opening (44), the retaining mechanism (22) having at least one hatch (120) for closing the side access opening (44) adapted to compress the stack (16) between the hatch (120) and the opposite face.

12. Battery module (10) according to any one of the preceding claims, wherein the electrical connection tabs (62, 64) are immersed in the dielectric liquid (30).

13. Battery module (10) according to claim 12, comprising at least one connection system (24) and / or at least one electronic management system (28) of the battery module (10) connected to each electrical connection tab (62, 64), the connection system (24) and / or the electronic management system (28) being immersed in the dielectric liquid (30).

14. Battery module (10) according to any one of the preceding claims, wherein each electrochemical cell (18) comprises a pouch (60), in particular is a pouch-format lithium ion electrochemical cell or wherein each electrochemical cell comprises a prismatic element, the dielectric liquid present in the or each open channel (82A, 82B) of dielectric liquid circulation being in contact with the pouch (60) or the prismatic element.

15. Battery, comprising at least one battery module (10) according to any one of the preceding claims.

16. Vehicle, in particular motor vehicle, space vehicle or aircraft, comprising at least one battery according to claim 15.

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