Battery module with controlled hydraulic pressure

Abstract

The invention relates to an all-solid battery module comprising a housing that defines an internal cavity. At least one end piece closes an access to the internal cavity, the end piece being attached to the housing. There are cells present in the internal cavity, which cells are immersed in a liquid contained in the internal cavity. The battery module is sealed so that the fluid exerts isostatic pressure on the cells. The present description also relates to a method for managing the operating pressure and temperature of a battery module.

Description

HYDRAULIC PRESSURE REGULATED BATTERY MODULE TECHNICAL FIELD

[0001] This description relates to battery modules and the management of battery operating pressure. CONTEXT

[0002] Certain operating parameters allow optimal exploitation of battery cells such as all-solid-state batteries. According to current knowledge, precise, active and dynamic management of battery operating pressure and temperature values ​​is likely to be critical to minimize or eliminate the occurrence of dynamic porosities or "voids" during rapid discharge ("stripping" phase), which subsequently promote the formation of dendrites during rapid charging; to increase the charging speed while limiting / eliminating the process of dendrite formation and propagation during "plating"; to increase battery life (capacity maintenance, minimization of "dead" or inactive lithium); to limit the rate of increase in battery cell impedance over cycles; to work harden dendrite areas / tips (increase in the diffusion / transport of lithium or other metal constituting the anode);to ensure that the quality of contacts at the cathode-electrolyte-anode interfaces of the cells is maintained; to minimize / eliminate damage to the cells in the event of extraordinary stress; and / or to fully exploit the potential of new generation batteries.

[0003] On the other hand, the presence of dynamic management systems can reduce overall efficiency due to their energy consumption, volume and weight, in addition to having to take into account the costs associated with such systems. SUMMARY

[0004] An object of the present description is to propose a simplified system for managing battery operating pressure and temperature.

[0005] According to a first aspect of the present description, there is provided a battery module comprising: a housing defining an internal cavity; cells in the internal cavity, the cells being bathed in a fluid contained in the internal cavity, the cells adapted to be connected to an electrical circuit; and characterized in that the battery module The battery is hermetically sealed to allow the fluid to produce isostatic pressure on the cells, and to maintain the fluid mass in the battery module constant during use of the battery module in sealed mode.

[0006] According to the first aspect, for example, at least one Peltier module is in contact with the housing, the Peltier module being activated to selectively heat or cool the fluid contained in the internal cavity.

[0007] Still according to the first aspect, for example, the Peltier effect module includes fins on its free surface.

[0008] Still according to the first aspect, for example, at least one compression element is between at least two adjacent cells.

[0009] Still according to the first aspect, for example, at least one resistive element is in the internal cavity to heat the fluid.

[0010] Still according to the first aspect, for example, at least one finned plate is in contact with the housing.

[0011] Still according to the first aspect, for example, at least one pump is in the internal cavity of said housing to circulate the fluid.

[0012] Still according to the first aspect, for example, which fluid is oil.

[0013] According to a second aspect, there is provided a battery system comprising: at least one battery module as described below; a control system comprising at least one processor, and a computer readable memory having stored instructions to be executed by said at least one processor to: monitor the temperature and / or pressure of said at least one battery module, and when using said battery module, activate cooling or heating of said module if said temperature and / or said pressure of the module is outside predetermined values, while maintaining the mass of fluid in said battery module constant and hermetically isolating said battery module from adding and removing fluid.

[0014] According to the second aspect, for example, at least two of said battery modules, the two battery modules having characteristics defined by pressure versus temperature curves different from each other.

[0015] Still according to the second aspect, for example, the curves differ in slope.

[0016] Still according to the second aspect, for example, the curves differ in pressure value for the same temperature.

[0017] Still according to the second aspect, for example, an enclosure is provided for each battery module, the enclosure defining a convection corridor for controlling the temperature of said battery module.

[0018] Still according to the second aspect, for example, the speakers are connected in series to form a continuous convection corridor.

[0019] Still according to the second aspect, for example, at least one valve is between two of said enclosures.

[0020] Still according to the second aspect, for example, the speakers are side by side.

[0021] Still according to the second aspect, for example, each enclosure has a valve downstream of the convection corridor.

[0022] Still according to the second aspect, for example, a fan is upstream of said convection corridor of at least one of said enclosures.

[0023] According to a third aspect, there is provided a method for managing the operating pressure and / or temperature of at least one battery module, the method comprising the steps of: housing cells of the battery in an internal cavity of at least one battery module, the internal cavity being hermetically sealed and the cells being bathed in a fluid; monitoring the temperature and / or pressure of the module; and during use of the battery, cooling or heating the module if said temperature and / or said pressure of the module is deviating from predetermined values ​​by maintaining the mass of fluid constant in the battery module by hermetically isolating said battery module from fluid addition and removal.

[0024] Still according to the third aspect, for example, cooling or heating the module is done by actuating a Peltier effect module by controlling a current direction.

[0025] According to another aspect of the present disclosure, there is provided a method of managing operating pressure and temperature of a battery module, the method comprising the steps of: housing battery cells in an internal cavity of the battery module, the internal cavity being hermetically sealed and the cells being bathed in a fluid; monitoring the temperature and / or pressure of the module; and during use of the battery, cooling or heating the module if said temperature and / or said pressure of the module is outside predetermined values. DESCRIPTION OF DRAWINGS

[0026] Reference is made to the figures accompanying this text in which:

[0027] Fig. 1 is a system having battery modules designed according to an embodiment of the present disclosure;

[0028] Fig. 2 is a perspective view of a battery module designed according to the present description, with a cap removed and cells partially removed from a housing;

[0029] Fig. 3 is a perspective view of the battery module of Fig. 2 with the end cap removed and the cells fully in the housing;

[0030] Fig. 4 is a perspective view of the battery module with the end caps attached to the housing;

[0031] Fig. 5 is an exploded perspective view of the battery module housing of Fig. 1 with its end caps;

[0032] Fig. 6 is a perspective view of a series of cells of the battery module of Fig. 2, according to one embodiment;

[0033] Fig. 7 is an elevation view of the cells of Fig. 6;

[0034] Fig. 8 is a battery having a geometry distinct from the battery module of Fig. 2;

[0035] Fig. 9 is a view of the cells of the battery module of Fig. 8;

[0036] Fig. 10 is an elevation view of the cells of the battery module of Fig. 8;

[0037] Fig. 11 is a fragmentary view of a Peltier module type heating / cooling system that may be used on the battery module housing of Fig. 2, according to one embodiment;

[0038] Fig. 12 is an end view of the battery module of Fig. 2 having Peltier module type heating / cooling systems as in Fig. 11;

[0039] Fig. 13 is another end view of the battery module of Fig. 2 with Peltier module type heating / cooling systems as well as passive heat sink fins for the housing;

[0040] Fig. 14 is a perspective view of a housing having heating elements;

[0041] Fig. 15 is a schematic view of an enclosure for a battery module of Fig. 2; and

[0042] Fig. 16 is a perspective view of three enclosures used in conjunction with each enclosure incorporating one of the battery modules of Fig. 2;

[0043] Fig. 17 is a graph showing the pressure versus temperature curves for three battery modules according to Fig. 2, with different starting pressures;

[0044] Fig. 18 is a graph showing the pressure versus temperature curves for three battery modules according to Fig. 2, with different case materials;

[0045] Fig. 19 is a graph showing the pressure versus temperature curves for three battery modules according to Fig. 2, with different compression members and / or different case materials;

[0046] Fig. 20 is a graph showing the evolution of the fluid pressure as a function of its temperature for a battery module according to the present description, with a Peltier effect module;

[0047] Fig. 21 is a graph showing the evolution of the pressure and temperature of the fluid as a function of time for a battery module according to the present description, with a Peltier effect module, during a first test;

[0048] Fig. 22 is a graph showing the evolution of fluid pressure and temperature as a function of time for a battery module according to the present description, with a Peltier effect module, during a second test; and

[0049] Fig. 23 is a graph showing the evolution of the fluid pressure as a function of its temperature for a battery module according to the present description, with a Peltier effect module, with or without compression members. DETAILED DESCRIPTION

[0050] Referring to the figures and more particularly to Fig. 1, a system for the use and control of batteries according to the present description is illustrated at number 1. The system 1 comprises three battery modules 10 described below, although there may be more or fewer of these battery modules 10 in the system 1. According to one embodiment, the battery modules 10 can be described as being all-solid-state batteries and which are controllable in pressure and / or temperature, in particular by using the Peltier effect. The battery modules 10 can also be used in all-solid-state, liquid, hybrid electrolyte batteries, etc. The battery modules 10 can also be identified by battery, cell module, etc. The battery modules 10 of the system 1 may have different operating characteristics, in particular according to the configurations described for Figs. 17 to 19.As explained below, the system 1 has the characteristic of being able to be operated while maintaining a constant mass of fluid (e.g., oil) in the battery modules 10 in a hermetic mode of operation, while simultaneously allowing pressure and / or temperature control in the battery modules 10, unlike certain dynamic systems which vary the mass of oil in the battery modules 10 during operation to control the pressure and / or temperature. When mentioning the operation of the system 1, this involves recharging the batteries and / or using the batteries to supply an energy demand. The variations in pressure and / or temperature may be related to several factors, such as recharging, discharging, ambient conditions of the battery environment, cooling, etc.The system of Figure 1 shows various battery management modules, such as a BMS battery management system, a temperature control subsystem having a temperature regulation module with thermocouples or other temperature measuring devices, a temperature adjustment module, according to setpoints. The battery management system therefore comprises at least one processor, and a medium or memory readable by the processor and comprising machine instructions, the medium and / or the readable memory having stored statements and instructions which must be executed by a computer to carry out a temperature control method as described herein. Description. By the BMS management system, the current direction to a Peltier module can be reversed to heat or cool the battery module.

[0051] In the context of this disclosure, a battery or battery module 10 comprises cells that are composed of two electrodes - a positive pole (or cathode) and a negative pole (or anode) - separated by a medium acting as an ionic conductor, called an electrolyte. The cells can be of different architectures, formats and dimensions. The anodes, cathodes and electrolytes can be made of different materials. The electrolyte can be liquid, solid, hybrid (polymer, ceramic, liquid, etc.). The all-solid-state battery is one embodiment among others. The cells are connected to an electrical circuit for their use.

[0052] In Fig. 2, the battery module 10 is shown in a partially exploded view. The battery module 10 comprises a housing 20 (i.e., tubular element), designed to incorporate cells 30. An on-board circuit may be connected to the cells 30 to control their operation and monitor their state of charge. The on-board circuit(s) may include power units, energy dissipaters, current limiters and an intelligent charger (not shown), making it possible to generate the relevant conditions of pressure, temperature and current density to obtain the optimal performance of the battery modules 10. This or these on-board circuits may be inside or outside the modules. End caps 40 (i.e., end members) are at the ends of the housing 20 to seal the interior of the battery module 10.The battery module 10 may optionally include heating elements such as Peltier effect modules 50 shown in Fig. 11, or resistive elements 50', illustrated in Fig. 14, a pump 60 as shown in Fig. 14 also, and the battery modules 10 may be inside enclosures 70 such as shown in Fig. 16. The cells 30 are immersed in a fluid retained by the housing 20. The fluid may be a liquid, preferably an oil, and more preferably a mineral oil to neutralize potential chemical reactions in the event of a defective or damaged cell. This neutralizing effect occurs, among other reasons, due to the chemical properties of the fluid, the absence of oxygen around the cells, and / or the application of isostatic pressure based on an incompressible fluid, etc.In particular, the use of oil can help avoid the combustion effect resulting from a chemical reaction of a defective cell, by isolating such a cell from ambient oxygen.

[0053] In the embodiment of Fig. 2, the housing 20 has a hollow body 21 of cylindrical shape. This cylindrical shape is illustrated by the outer surface 21A of the hollow body 21. The outer surface 21A may be smooth and cylindrical in shape, or may have other and surface components, such as dissipation fins 21 B shown in Fig. 13, described above.

[0054] The housing 20 also defines an internal cavity 22 (Ie., a chamber) as defined by the inner surface 22A. The internal cavity 22 may be cylindrical in shape or may have other formations on its inner surface 22A, as may the outer surface 21A, with embodiments described below. Optionally, flanges 23 are positioned at the ends of the hollow body 21. The flanges 23 are of the radially projecting type. Holes 23A in the flanges 23 may be circumferentially disposed in the flange 23 to enable the end caps 40 to be secured to the housing 20. Various other features may be present, including seals to ensure that the fluid within the battery module 10 remains there, i.e., oil.

[0055] The housing 20 receives in its internal cavity 22 a plurality of cells 30. The cells 30 may have a body 31 with chemical storage elements. As illustrated in Fig. 7, the body of the cells 30 may be in the form of a bag. Connectors 32 are at the ends of the body 31 and serve for the connection of electrodes and / or for connecting the cells 30 to each other. As shown in Fig. 3, some of the cells may be separated by compression members 35. The compression members 35 are for example plates of different compressibility values, which make it possible to design battery modules 10 having a desired relationship of increase in pressure value as a function of increase in temperature value, as shown in Fig. 19, described below. The compression members 35 are optional, and may take different forms.In particular, by way of example only, the compression members 35 may be elastomeric foam panels, bubble wrap sheets, etc. Electrical connection arrangements, pads 36 and other components may be present to hold the cells 30 in position, to connect them to an electrical circuit, to space them. These components may be similar to those present in International Patent Application No. PCT / CA2022 / 051538, filed on October 19, 2002, the content of which is incorporated into the present patent application by reference.

[0056] In Figs. 2-5, the end caps 40 are shown as having a closure body 41 of hemispherical or dome shape. Other geometries are considered. Thus, the closure body 41 has an outer surface 41A of hemispherical shape. Due to the three-dimensional shape of the closure body 41, the end cap 40 may have an internal cavity 42 (Fig. 5) defined by an inner surface 42A. This internal cavity 42 may be in fluid communication with the internal cavity 22 of the housing 20, although a plate may be used to create an isolated chamber in at least one of the end caps 40. This chamber isolated could in particular receive electronic components which must not be immersed in the fluid of the housing.

[0057] A flange 43 may project radially from the closure body 41. The flange 43 may have a geometry similar to the flanges 43 of the housing 20. The holes 43A are circumferentially disposed on the flange 43 and allow the use of fasteners such as screws and bolts to secure the end caps 40 to the housing 20. For example, these fasteners are illustrated as 43B in Fig. 5. Ports 44 may be at the end of the end caps 40 or at other locations. Ports 44 allow the injection of a fluid into the housing 20. It can be seen in Figs. 3 and 4 that there are ports 44 at both ends of the battery module 10. These ports 44 are fluid inlets and / or outlets, and may allow, in particular, a gas to escape when filling the battery module 10 with oil, for example.The port 44 may include a valve or other form of plug to allow the injection of liquid into the battery module 10 and its subsequent drainage, while being sealed during use. The ports 44 may be located elsewhere, such as on the housing 20. The port 44 may include a safety valve / relief valve for venting oil or gases if the pressure inside the module 10 exceeds the maximum design value. As illustrated in Fig. 5, a compression member 45 may be positioned in one or both of the end caps. The compression member 45 may be a pad with a given resilience. The compression members 45, like the compression members 35, contribute to controlling the pressure inside the battery module 10.Despite the presence of port(s) 44 in the battery modules 10, the port(s) 44 may be closed during operation of the battery modules, so that the mass of fluid in the battery modules 10 does not vary during use. The battery module 10 is in a sealed mode, in that the fluid in the battery module 10 cannot exit the housing during use of the battery module 10 in recharging / discharging, and no fluid can be added to the housing during this sealed mode. The battery module 10 is hermetically isolated from addition and removal of fluid. That being said, in certain circumstances, there may be an addition or loss of fluid mass, in particular by leakage, filling, but such variations may be negligible, and do not constitute the method by which the system 1 will regulate its temperature and / or its pressure.

[0058] Thus, the battery modules 10 comprise the series of cells 30 in a row as shown in Fig. 6. The cells 30 may therefore be inserted into the hollow body 21 so as to fill the housing 20. There may be compression members 35 between some of the cells 30.

[0059] Although the cylindrical housing shape is advantageous for a pressure vessel, it is possible to have housings 20 having a different shape. An example is shown in Figs. 8 to 10, in which the housing 20 has a prismatic shape. To allow comparison between the battery modules of Figs. 2 to 7 and Figs. 8 to 10, the same reference numbers will be used for components having the same functionalities, despite the geometric differences.

[0060] Although the cells 30 may be circular or square in shape, one configuration contemplated is to have two stacks of rectangular cells 30 as shown in Figs. 9 and 10. Thus, the cells 30 of Figs. 9 and 10 have the elongated body 31 with connectors at the ends, connectors being shown as 32. Compression members 35 may be present between some of the cells 30. Thus, as shown in Fig. 8, there may be two or more stacks of cells 30 side by side. The end caps 40 of Fig. 8 are flat plates rather than having a hollow body. Figs. 8 to 10 are only one solution among others.

[0061] Fig. 11 shows a Peltier module 50, which may optionally be used in the various battery modules 10 described in this specification. The Peltier module 50, also described as a Peltier module heating / cooling system, converts an electrical current into a temperature differential. The direction of the current supplied to the Peltier module 50 may be reversed for heating or cooling. The Peltier module 50 may thus comprise two faces, one being cold and the other being hot, the terms "cold" and "hot" being used interchangeably. In one embodiment, the Peltier module 50 is constructed from a series of semiconductor pairs, the electrons of these pairs acting as heat transfer fluids. In one embodiment, the faces are ceramic (or other material) plates, separated for example by semiconductor pellets. In Fig.11, the Peltier module 50 comprises a face 50A which has a shape corresponding to that of the outer wall 21A of the hollow body 21 of the housing 20 to bear against it for heat conduction, so that supplying a current into the Peltier module 50 makes it possible to heat or cool the fluid in the internal cavity 22. This shape is a cylindrical surface segment, but could be other, in particular if the housing 20 is prismatic. The face 50A could in particular be flat. It could also be considered that the wall of the housing, or a part of the wall, could be a Peltier module. Optionally, the opposite face of the Peltier module 50 may be provided with fins 50B to contribute to the exchange of heat with the ambient environment of the module 10.By passing a current through the Peltier effect module 50, in particular via the cables 50C, the fluid of the internal cavity 22 can be heated by conduction via the face 50A of the Peltier effect module 50 in contact with the outer wall 21A of the hollow body 21 of the housing 20. By thermal expansion effect of the. fluid, the internal pressure of the housing 20 will increase. By reversing the direction of the current in the Peltier module 50, the fluid in the internal cavity 22 is cooled by the face 50A of the Peltier module 50 in contact with the outer wall 21A of the hollow body 21 of the housing 20. The direction of the current can be controlled by the BMS. By thermal expansion effect of the fluid, the internal pressure of the housing 20 will decrease. As shown in Figs. 12 and 13, different distributions and configurations of Peltier modules 50 can be present depending on the effect that is desired. Fig. 11 shows a Peltier module 50 provided with four fins 50B, but these fins 50B are optional, where they can be less than four or more than four. In the embodiment of Fig. 12, the housing 20 is surrounded by eight of the Peltier modules 50 of Fig. 11, as an example. In Fig.13, passive dissipation fins 21 B are also present, optionally in combination with Peltier effect modules 50. These passive dissipation fins 21 B can be made directly on the outer wall 21A of the housing 20, or can have a geometry similar to the Peltier effect modules 50, among others, with a face matching the housing 20, and fins in a radial direction or other direction.

[0062] In Fig. 14, heating elements 50' are inside the battery module 10. The heating elements 50' are illustrated as being resistive element rods. It may be considered to install them at certain portions of the housing 20 to assist in heating the fluid of the internal cavity 22. These heating elements 50' may be on the exterior surface of the housing 20, and / or in the wall of the housing, among other possibilities.

[0063] In Figs. 15 and 16, enclosures 70 are illustrated. The enclosures 70 define an interior volume 70A in which the battery modules 10 are positioned, the interior volume 70A being a convection corridor. For each enclosure 70, an air intake flap 71 and air exhaust flaps 72A and 72B may be present and a fan 73 may cause air movement within the enclosures 70. The intake flaps 71 and exhaust flaps 72A, 72B may be arranged so that air circulates in series within the enclosures 70 which are positioned side by side. In particular, some of the exhaust valves 72A can exhaust air to the outside while other exhaust valves 72B allow air to circulate between enclosures 70. This is optional. The enclosures 70 allow cold air or hot air from a module to be recovered by convection, forced or not.This hot or cold air is either exhausted to the outside or redirected to the other enclosures to contribute to the heating or cooling of the adjacent modules. In the arrangement of Fig. 16, two types of enclosure are shown, and allow air circulation in series between enclosures 70. The enclosures 70 can also be used in parallel with each other, each of the enclosures 70 having for example its own fan 73. The control of the valves 71, 72A and 72B can be carried out so as to conform to the optimum operating pressures of the. different modules 10, according to Figs. 17 to 19. Although the enclosures 70 are illustrated side by side, with a serpentine convection path, other arrangements are considered, depending in particular on the space available. For example, enclosures 70 could be end to end, and / or one on top of the other.

[0064] Now that various embodiments of the battery module 10 are described, the control of the pressure and / or temperature of the battery modules 10 is specified. The present disclosure proposes to construct the system 1 (Fig. 1) which makes it possible to regulate the pressure of the fluid inside a module 10 while only controlling the temperature of the fluid. In other words, the system 1 (Fig. 1) makes it possible to regulate the pressure of the fluid inside a module 10 by using only electrical energy to cool or heat the module 10. This regulation can be done while keeping the mass of fluid in the module 10 constant, ie, the module 10 is sealed and does not vary its fluid content during operation and temperature control. The system 1 can be operated by monitoring only the temperature of the modules 10.This can be called the hermetic mode of operation of the battery module 10, during which there is no intentional addition or removal of fluid (e.g., oil) from the housing. This control is based on the fact that the thermal expansion of the oil or other pressurized fluid contained in a hermetic reservoir at constant volume results in an increase in the pressure in the reservoir as the temperature of the oil increases. This relationship between the increase in the temperature of the fluid and the increase in the pressure in a reservoir closed in hermetic mode, and not operating a variation in the mass of fluid, such as the housing 20 with end pieces 40, is quasi-linear, depending on the coefficient of thermal expansion and the bulk modulus of the oil.

[0065] By using several battery modules 10 in the same system (eg, system 1), it is possible to design modules 10 for which the pressure evolution profile as a function of temperature are different (non-linear or linear with different slopes), and therefore create a system 1 having different performance characteristics specific to the battery modules 10, and complementary if desired. The simplicity of this pressure control can result in the elimination of several subsystems, and therefore can result in a better energy density (Wh / I) of the modules 10; a better specific energy (Wh / kg) of the modules 10. This can be done by the design / use of several modules 10 in parallel, of the same chemistry or different chemistries, which would have complementary performance characteristics: low temperature operation module, power module, energy module (autonomy), sacrifice module.

[0066] Referring to Fig. 17, a graph is shown illustrating the pressure versus temperature curves for three different modules 10. These modules 10 have the same sealed reservoirs (volume and shape) and are made of the same material. The pressure evolution profile as a function of temperature will be the same (same slope) for the three modules 10. We can therefore design, for example, three different battery modules 10, by fixing the pressure of the modules 10 at different initial values, for an initial operating temperature value, for example 25°C.

[0067] In Figure 18, another graph is shown illustrating the pressure curves as a function of temperature, for three different modules 10. These modules 10 have the same hermetic reservoirs (volume and shape), but are made of different materials, for example magnesium, aluminum, steel. The pressure evolution profile as a function of temperature will not be the same (different slopes). We can therefore design, for example, three different battery modules 10, by fixing the pressure of the modules 10 at the same initial value, for an initial operating temperature value, for example 25°C. This approach is based on the Young's modulus of the materials, which dictates the plastic deformation of a material as a function of the stress to which it is subjected, here the internal pressure of the reservoir, i.e., the casing 20. A material whose Young's modulus is very high is said to be rigid.A 20-mm can made of standard aluminum (Young's modulus of 69 Gpa), subjected to the same operating pressure as the same 20-mm can made of stainless steel (Young's modulus of 203 Gpa), will deform more. The pressure exerted by the expanding oil (temperature increase) on the aluminum 20-mm can will therefore increase less rapidly because the volume of the 20-mm can will increase slightly under the pressure (deformation of the aluminum). Similarly, a 20-mm can made of magnesium (Young's modulus of 45 Gpa), subjected to the same operating pressure as the same standard aluminum tank (Young's modulus of 69 Gpa), will deform more.

[0068] In Figure 19, another graph is shown illustrating the pressure curves as a function of temperature, for three different modules 10. These modules 10 have the same hermetic housings 20 (shape and volume), may be made of the same material. On the other hand, a part of the interior volume is made of different compressible materials (type and / or quantity), for example in the form of compression members 35 and / or 45. Consequently, the pressure evolution profile as a function of temperature will not be the same (different slopes). It is therefore possible to design, for example, three different battery modules 10, by fixing the pressure of the modules at the same initial value or not, for an initial operating temperature value, for example 25°C.This approach is based on the compressibility modulus of the materials 35 and / or 45 which are inserted into the internal cavity of the housing 20, potentially including the interior of the end pieces 40 for the compression members 45. The compression members 35 and / or 45 could be in the form of pieces of elastomers, foams or other more or less compressible materials, in greater or lesser quantities. These compression members 35 and / or 45, depending on their isostatic elasticity moduli (or even compressibility), are. would deform more or less under the fluid pressure in the module 10, which would result in different rates of pressure increase as a function of temperature, depending on the differences between compression members 35 and / or 45. This approach can be defined by the ability to design a reservoir (i.e. casing) having a so-called global Young's modulus (MYG), determined by all the Young's moduli of the constituents of the module 10.

[0069] Figures 20 to 23 show various graphs illustrating the pressure and temperature of a battery module 10, under various operating conditions, by way of non-limiting example. Figure 20 is a graph showing the evolution of pressure as a function of temperature for a battery module according to the present disclosure, provided with an aluminum housing 20 as an example, with a Peltier module of the type illustrated by 50. The Peltier module 50 was operated to heat and then cool the battery module 10. Figures 21 and 22 are for the aluminum housing 20, and illustrate the pressure and temperature which follow, in tests at different starting temperatures and pressures, again with heating and cooling by the actuation of the Peltier module 50.Finally, Figure 23 relates to the evolution of the pressure as a function of the temperature for a battery module 10 made of aluminum or steel, by the actuation of the Peltier effect module 50, with or without compression members, such as those shown by 35. It can be seen there that the compression members 35, such as bubble wrap or foam, can modify the rate of variation of pressure of the fluid in the battery module 10, as a function of its temperature.

[0070] Having established the design of the battery module 10, the rate of change of pressure as a function of the temperature change can therefore be fixed and predictable. It is therefore necessary to be able to effectively regulate the temperature in the battery modules 10. The qualities of an effective temperature control system for such an application may be among the following: • Rate of change of operating temperature (°C / second); • Temperature uniformity over the surface area of ​​30 cells of 10 modules; • Energy consumption of system 1; • Volume and weight of system 1 (specific energy and energy density of the module); • Complexity of system 1 and its peripheral systems; • Robustness; • Safety in the event of an incident, fault, short circuit or thermal runaway.

[0071] Furthermore, some background on the chemistries of all-solid-state batteries must be considered. It is currently believed that polymer electrolytes require a lower operating pressure than that required for ceramic-based electrolytes (e.g., 200 psi versus 900 psi). A battery module 10 should therefore accommodate a fairly wide pressure range. A higher operating temperature (30°C and above), while respecting material characteristics and safety aspects, promotes better performance of the cells 30. At low temperatures (e.g., 0°C), the battery modules 10 are either unusable or perform very poorly. It is believed that a higher operating pressure, while respecting material characteristics and safety aspects, promotes better performance of the cells 30, or does not affect the performance of the cells 30.In operation, the cells 30 of the modules 10 generate heat which can be used to heat the oil of the module 10 in which they are located. This heat can also be recovered to heat the oil of another module 10. Therefore, according to one embodiment, the modules 10 will be heated, for example by the heating elements 50, and therefore operate at higher pressure. The main pressure regulation function could therefore be based on evacuating the heat to other modules 10 or to the outside of the module 10.

[0072] Various embodiments can be implemented for the management of pressure and temperature in the battery modules 10, taken individually or in groups. In particular, the circulation of oil can be induced in the module 10, for the exchange of heat with the cells 30, aiming at the uniformity of the temperature of the cells 30. One approach recommends heating the oil from the bottom of the housing 20 (eg, Fig. 14, heating elements 50) and the hot oil migrates upwards, by gravity, due to the lower density of the hot oil compared to the cold oil, the oil circulating through the interstices separating the cells 30. In the same way, the cells are cooled from the top of the housing 20 and the cold oil migrates downwards. The heat dissipation fins 21 B of Fig. 13 and an external convection on the housing 20 can among other things contribute to the cooling of the oil. The circulation of the oil can be forced, for example by pump 60 (Fig.14) located in the housing 20, so as to force the circulation of the oil on the cells 30 by conduits promoting an optimal heat exchange, without however modifying the mass of fluid in the module 10 during the operation, in a hermetic mode. In addition to the different systems shown above, such as the Peltier effect modules 50, the heating elements 50', etc., it is possible to use other means to heat or cool the battery modules 10. For example, the battery modules 10 could be heated and / or cooled by an external refrigeration system of the pipe type with refrigerant, in particular used as a heat pump, the refrigerant pipes being in contact with the housing 20. Another example of a refrigeration system with Carnot cycle would be achieved by an external heating system using heat transfer fluid, eg, water, glycol, circulating in pipes and. surrounding the housing 20 of the module or modules 10, etc. In another example, a refrigeration system uses a heat transfer circuit with a heat sink (eg, ambient convection by radiator for moving vehicle), without a Carnot cycle. These examples are some among others allowing the temperature of the modules 10 to be controlled.

[0073] The heat generated by the cells 30 themselves may contribute to temperature control. The oil is heated using the heat generated by the cells 30 in operation, and the pressure of the module 10 is adjusted. The system 1 may include multiple modules 10, and recovery of the heat removed by one of the modules 10 having reached its operating temperature to contribute to heating the other modules 10. The enclosures 70, or other conduits may in particular serve to contain the heat and direct it to other enclosures to heat the modules 10 in these other enclosures. Fans may be used to force convection and removal of heat to the other modules 10 requiring heat.

[0074] The system 1 may also be provided with one or more Peltier effect modules 50. Such module(s) 50 has one surface in contact with the wall(s) of the housing 20, and another surface exposed to the ambient environment. In a heat dissipation scenario, the Peltier effect module 50 may be powered so that its cold surface is in contact with the walls of the housing 20, and the hot surface is toward the outside of the housing 20.

[0075] Various of these configurations can be combined according to the needs of the system 1 .

[0076] Overall, the system 1 can be controlled according to certain considerations. From the perspective of regulating the temperature of the oil in which the cells 30 are immersed, the heat generated by the latter during operation can be either recovered or evacuated. It is generally advantageous to operate all-solid-state batteries at the highest possible temperatures, while remaining below the limit values ​​dictated by the properties of the materials from which the cells are made. At low ambient temperatures (0°C for example), it will be advantageous to retain this heat for optimal operation of the cells 30, or to recover it from one module 10 to allow the temperature of another module 10 to be raised. At high ambient temperatures (45°C for example), the all-solid-state battery cells 30 will be more efficient / effective.

[0077] The housing 20 of the modules 10 includes the cells 30, the fluid such as oil and the oil heating / cooling systems discussed above, the latter being located inside or outside the housing 20.

[0078] For the purposes of heat recovery and exchange between the different modules 10, the latter can be placed in enclosures 70, isolating the modules 10 from each other, the enclosures 70 communicating with each other when necessary depending on the temperatures. The heat exchange system between the different modules 10, in particular by the enclosures 70, therefore aims to optimally use the heat naturally generated by the cells 30 during their operation. The heat generated by its cells 30 can be stored in a module 10, redirected to another module 10, or evacuated from the system 1.

[0079] Devices for cooling the oil (e.g., Peltier module 50, fins 21 B, enclosures 70) or heating the oil (heating element 50', Peltier module 50) are used when the operating parameters of the battery suggest it and the conditions naturally generated by the system (including the ambient temperature parameter) do not allow the battery to operate optimally. Despite its heating and cooling, the system 1 keeps the mass of oil in the battery module 10 constant. This can be called a hermetic mode of operation of the battery.

[0080] The enclosures 70 therefore define a closed structure, provided with valves which can be in the open or closed position, and these are controlled by a control system managed by the BMS battery management system, for example via an actuator, of the solenoid type for example. These valves 71 and 72A.72B allow the admission of outside air into the enclosure 70, the exhaust of air to the outside of the enclosure 70 or the exhaust of air to the enclosure 70 incorporating the adjacent module 10. Each valve may correspond to an aligned opening in the adjacent module.

[0081] To enable efficient heat exchange, by convection, a fan may be placed at the end of the enclosure 70. To enable efficient transfer of air from one enclosure 70 to another, different designs of enclosure 70 may be used. Thus, according to Fig. 1, the air expelled from an enclosure 70 is either hot or cold. An efficient example of a possible module configuration (module 1, module 2, module 3) would involve the hot air from the enclosures being expelled to the adjacent module (T°Module 1 < T°Module 2 < T°Module 3). In this way, the system design would result in three complementary modules 10, either based on cells with different chemistries, and / or based on modules 10 with different functions (energy versus power, for example), and / or either on modules having different pressure evolution profiles as a function of temperature, therefore also dedicated to different functions, in particular according to Figs. 17 to 19.

[0082] The system 1 is therefore simple in that it operates heating and / or cooling while keeping the oil mass constant in hermetic mode, and makes it possible to regulate both the operating temperature of the cells 30 and the pressure of the fluid inside a module 10, by controlling only the temperature of the fluid trapped in the module 10, i.e., no addition or removal of oil during the operation. If desired, the system can therefore operate without a mechanical or other pressure system, cell cooling system, pump, valve, reservoir, etc. In addition, the oil in which the cells 30 are bathed serves to neutralize / delay / prevent the chemical reactions of the cells 30 in the event of failure.

[0083] The battery module 10 can therefore be defined as comprising a housing defining an internal cavity; at least one end piece closing an access to the internal cavity, the end piece being fixed to the housing, the end piece being optional. Cells are in the internal cavity, the cells being bathed in a liquid contained in the internal cavity. The battery module is hermetically sealed so that the fluid produces an isostatic pressure on the cells. The fluid having a very high modulus of bulk (oil versus air) will be said to be incompressible. Incompressible fluids, versus so-called compressible fluids, applying an isostatic pressure on the battery cells, can have a favorable effect on the performance of the battery cells and on their safety of use.A battery system may comprise at least two of these battery modules, the two battery modules having characteristics defined by pressure-temperature curves that are different from each other. In particular, the curves differ in slope and / or the curves differ in pressure value for the same temperature.

[0084] The present disclosure also provides a method for managing operating pressure and temperature of a battery module, the method comprising the steps of: housing battery cells in an internal cavity of the battery module, the internal cavity being hermetically sealed and the cells being bathed in a fluid; monitoring the temperature and / or pressure of the module; and during use of the battery, cooling or heating the module if said temperature and / or said pressure of the module is outside predetermined values.

Claims

CLAIMS 1. A battery module comprising: a housing defining an internal cavity; cells in the internal cavity, the cells being bathed in a fluid contained in the internal cavity, the cells adapted to be connected to an electrical circuit; and characterized in that the battery module is hermetically sealed so that the fluid produces an isostatic pressure on the cells, and to maintain the mass of fluid constant in the battery module during use of the battery module in a hermetic mode.

2. The battery module of claim 1, comprising at least one Peltier effect module in contact with the housing, the Peltier effect module being activated to selectively heat or cool the fluid contained in the internal cavity.

3. The battery module of claim 2, wherein the Peltier effect module comprises fins on its free surface.

4. The battery module of any one of claims 1 to 3, comprising at least one compression element between at least two adjacent cells.

5. The battery module of any one of claims 1 to 4, comprising at least one resistive element in the internal cavity for heating the fluid.

6. The battery module of any one of claims 1 to 5, comprising at least one finned plate in contact with the housing.

7. The battery module of any one of claims 1 to 6, comprising at least one pump in the internal cavity of said housing for circulating the fluid.

8. The battery module of any one of claims 1 to 7, wherein the fluid is oil.

9. A battery system comprising: at least one battery module according to any one of claims 1 to 8; a control system comprising at least one processor, and a computer-readable memory having stored instructions to be executed by said at least one processor for: monitoring the temperature and / or pressure of said at least one battery module, and when using said battery module, activating cooling or heating of said module if said temperature and / or said pressure of the module is outside predetermined values, while maintaining the mass of fluid in said battery module constant and hermetically isolating said battery module from adding and removing fluid.

10. The battery system of claim 9, comprising at least two of said battery modules, the two battery modules having characteristics defined by pressure versus temperature curves different from each other.

11. The battery system of claim 10, wherein the curves differ in slope.

12. The battery system according to claim 10 or claim 11, according to which the curves differ in pressure value for the same temperature.

13. The battery system of any one of claims 9 to 12, comprising an enclosure for each battery module, the enclosure defining a convection corridor for controlling the temperature of said battery module.

14. The battery system of claim 13, wherein the enclosures are connected in series to form a continuous convection corridor.

15. The battery system of claim 14, comprising at least one valve between two of said enclosures.

16. The battery system of claim 15, wherein the enclosures are side by side.

17. The battery system of any one of claims 13 to 16, wherein each enclosure comprises a valve downstream of the convection corridor.

18. The battery system of any one of claims 13 to 17, comprising a fan upstream of said convection corridor of at least one of said enclosures.

19. A method of managing operating pressure and / or temperature of at least one battery module, the method comprising the steps of: housing battery cells in an internal cavity of at least one battery module, the internal cavity being hermetically sealed and the cells being bathed in a fluid; monitoring the temperature and / or pressure of the module; and when using the battery, cooling or heating the module if said temperature and / or said pressure of the module is outside predetermined values by maintaining the mass of fluid in the battery module constant by hermetically isolating said battery module from adding and removing fluid.

20. The method of claim 19, wherein cooling or heating the module is done by operating a Peltier effect module by controlling a current direction.

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