FR3141808A1 - Electric drum set - Google Patents

Abstract

The invention relates to an assembly for an electric battery comprising at least one electrical storage cell (3), said cell (3) comprising at least two electrical connection connectors (7, 8), said assembly further comprising at least one device for cooling (10) comprising an enclosure (11) comprising a refrigerant, said enclosure (11) comprising a zone capable of forming a condenser and a zone capable of forming an evaporator, the zone forming an evaporator being capable of exchanging heat with at minus one of the connectors (7, 8) of the cell (3), the condenser zone being capable of exchanging heat with a fluid external to said enclosure (11), the condenser zone having an exchange surface of heat with the external fluid greater than the heat exchange surface with the connectors (7, 8). Figure to be published with the abstract: [Fig. 1]

Description

Electric drum kit Technical field of the invention

The invention relates to an electric battery assembly, intended to equip a motor vehicle, in particular a vehicle with an electric or hybrid motor.

State of the prior art

A vehicle with an electric or hybrid motor typically includes a battery pack intended to power one or more electric motors. This includes a housing containing several electric accumulators, also called cells, intended to store and deliver electrical energy. The cells can be prismatic and arranged adjacent to each other.

The cells are also electrically connected within the battery pack using series and parallel connections. Connecting the cells in series increases the battery voltage, while connecting the cells in parallel increases the current delivered.

Cells require temperature management throughout their life cycle to avoid premature cell wear and severe battery malfunction, particularly a fire hazard. Temperature management is essential, both to recharge the battery at high power and to ensure that the amount of energy required to power the engine is delivered. The optimum operating temperature for a Li-ion cell, for example, is around 25°C. Cells maintain excellent performance if their temperature varies by less than 15°C from this optimum temperature.

The battery is conventionally cooled by circulating air or heat transfer fluid.

However, the cells are generally arranged in such a way as to reduce the overall size, so that only the end zones of the cells are accessible to exchange heat with the cooling fluid (water or heat transfer fluid).

Such cooling may be insufficient to ensure rapid recharge cycles which can lead to significant heating of the cells.

Presentation of the invention

This document aims to remedy this drawback in a simple, reliable and inexpensive way.

For this purpose, the present document relates to an assembly for an electric battery comprising at least one electrical storage cell, said cell comprising at least two electrical connection connectors, said assembly further comprising at least one cooling device comprising an enclosure comprising a refrigerant fluid, said enclosure comprising a zone capable of forming a condenser and a zone capable of forming an evaporator, the zone forming the evaporator being capable of exchanging heat with at least one of the connectors of the cell, the zone forming the condenser being capable of exchanging heat with a fluid external to said enclosure, the zone forming the condenser having a heat exchange surface with the external fluid larger than the heat exchange surface with the connector.

The enclosure thus forms a steam chamber operating according to the general principle of a heat pipe. Heat is taken from the connection and is transmitted to an external fluid, through the refrigerant fluid. The external fluid can be air or glycolated water, for example.

In operation, heat is produced by the cell and transferred to the refrigerant in the evaporator zone. The refrigerant is then evaporated and moves to the condenser zone where the calories are evacuated to the outside fluid, the refrigerant being then condensed and directed again to the evaporator zone.

The fact that the heat exchange surface of the evaporator zone is large makes it possible to maximize the evacuation of calories to the external fluid.

The connectors can be connected to an anode and a cathode of the cell.

Said assembly may be intended to equip a motor vehicle battery pack.

The assembly may comprise at least a first and a second electrical storage cell, the evaporator-forming zone exchanging heat with a first connection of the first cell and with a second connection of the second cell, said evaporator-forming zone comprising at least one electrically conductive part ensuring an electrical connection between said first connection of the first cell and said second connection of the second cell.

In this way, the enclosure not only ensures the heat extraction function but also the function of electrical connector between the connectors of the different cells. Indeed, the first connector can be connected to the anode of the first cell and the second connector can be connected to the cathode of the second cell, several cells can thus be connected in series, so as to form a battery.

Of course, a cooling device can be connected to a single connector of a single cell. Such a device can, for example, equip the corresponding connector of the first cell or the last cell of a set of cells electrically connected in series.

The entire enclosure can be made of a thermally and electrically conductive material.

The enclosure can be made by forming and assembling sheet metal.

The enclosure can be made of a copper or aluminum type material.

The assembly may comprise, for example, at least three cells intended to be electrically connected in series via at least two cooling devices. The cells are thus connected in groups of two cells.

At least the evaporator area may have cooling fins.

Said fins may have a flat shape or any other shape allowing to maximize the heat exchange surfaces between the fins and the external fluid. Said fins may be made of metal sheets, connected to the enclosure. The fins may for example be welded to the enclosure.

Said sheet metal may have corrugations, for example corrugations of rounded or polygonal sections, for example of rectangular sections, certain parts of which are connected to the enclosure and certain parts are intended to exchange heat with the external fluid.

The surface of the enclosure in contact with the connectors is for example between 5% and 30% of the total surface of the enclosure. Said surface in contact with the connectors may be flat.

The ratio of the total surface area of the fins to the external surface area of the enclosure is, for example, between 8 and 30.

The enclosure may have, when viewed from above, a generally rectangular shape. The length is defined as the largest dimension of the enclosure along a first axis. The width of the enclosure is defined as the second largest dimension of the enclosure along a second axis. The thickness of the enclosure is defined as the dimension of the enclosure along a third axis. The first, second and third axes may be orthogonal.

The first and second axes may define a plane generally parallel to the plane passing through the connectors or the corresponding ends of the cells.

The third axis can be roughly parallel to the largest dimension of the cells, that is, the longitudinal axis of the cells.

Each cell can be prismatic in shape.

Each cell, for example, has a parallelepiped shape, with four side faces and two end faces.

Alternatively, the cells may be cylindrical or pouch-shaped.

The connectors can be two in number per cell. The connectors can be located at one of the end faces of the prismatic cell.

The assembly may include several cells adjacent to their lateral faces.

The cells are for example Li-ion type cells.

The enclosure can be prismatic in shape.

The enclosure may comprise a first wall facing the cells and a second opposite wall, comprising at least one zone parallel to at least one zone of the first wall.

Spacers may be mounted between the first and second walls of the enclosure. Said spacers make it possible to avoid a separation or a rapprochement of the walls relative to each other.

The first wall and/or the second wall may be equipped with cooling fins.

A major part, i.e. at least 50% of the surface, of the first wall and/or the second wall may be equipped with cooling fins.

The evaporator area can be welded to each corresponding connector.

The enclosure may include at least one recess to facilitate spot welding of the enclosure to the corresponding connector from the side of the enclosure opposite the cells. Welding can thus be carried out in the bottom of the recess.

The internal surface of the enclosure may include capillary means allowing the movement by capillary effect of the refrigerant in liquid form from the condenser zone to the evaporator zone.

The capillary means may include channels formed on the internal surface of the enclosure.

The channels have, for example, a rectangular section. The section and/or shape of the channels are suitable for allowing such a capillary effect. Each channel can, for example, have a width and/or depth of between a few hundredths and a few mm.

Said channels may be parallel to each other, at least in part.

Alternatively, the capillary means may be formed by a wick covering at least a portion of the internal surface of the enclosure. Said wick may be formed by a layer of sintered material, such as for example a layer of sintered powder. Said sintered material is for example of the copper type.

Alternatively, the enclosure may be devoid of capillary means, the transport of liquid refrigerant from the condenser zone to the evaporator zone being able to be ensured by thermosiphon effect. In other words, the movement of the refrigerant is then ensured by temperature difference between the condenser zone and the evaporator zone.

The assembly may include at least two cooling devices capable of cooling cell connectors, said devices being mounted on a common support made of electrically insulating material.

Said support can be made of a flexible material allowing for acceptance of positioning defects of the cooling devices or assembly clearances between the different cells.

The said support is for example a plastic film.

Said support can be made of polyimide.

Said support can be made by a printed circuit. Such a printed circuit can provide other related functions, such as temperature or pressure sensors, or even means of transmitting or receiving low-power signals.

The refrigerant can be acetone, ethanol, methanol or a refrigerant liquid type R1233zd.

This document also concerns a vehicle comprising at least one assembly of the aforementioned type.

The vehicle is, for example, a motor vehicle, for example a car or a truck. Said vehicle is, for example, a vehicle with an electric or hybrid motor.

Said assembly may be suitable for equipping a battery pack of a vehicle.

Such a pack comprises, for example, a housing in which a large number of cells arranged adjacently are housed, for example in the form of at least one cell layer, said layer comprising cells arranged in rows and columns. At least some of the cells may be in contact with each other via lateral surfaces of said cells.

Brief description of the figures

is a perspective view of a portion of a battery pack according to one embodiment of the present document,

is a front view of part of said pack,

is a sectional view of a cooling device,

is a schematic view of a cell equipped with a cooling device,

is a top view showing the electrical connections between the connectors of several adjacent cells.

Detailed description of the invention

Figures 1 and 2 represent a battery pack 1 intended to equip a motor vehicle for example. This comprises a housing 2 inside which are housed cells 3, here prismatic cells 3, for example of the Li-ion type.

Each cell 3 (figures 4 and 5) has the shape of a rectangular parallelepiped, comprising four side faces 5, an end face called upper 6 in that it is shown on top in the figures, and an end face called lower 7.

The cells 3 can be arranged in rows and columns and may or may not be in contact with the adjacent cells by side faces 5. The upper end face 6 of each cell comprises a first and a second electrical connector 7, 8, connected respectively to a cathode and to an anode of the cell 3. Each connector 7, 8 comprises a flat upper end surface 9.

Cells 3 are intended to be electrically connected to each other, for example in series.

Pack 1 also includes cooling devices 10. Each cooling device 10 includes an enclosure 11 containing a refrigerant fluid, such as methanol for example.

The enclosure 11 comprising a zone 12 capable of forming an evaporator and a zone 13 capable of forming a condenser ( ). The enclosure 11 is formed by cutting, forming and welding two walls or metal sheets 14, 15 and delimits a sealed internal volume 16 containing the refrigerant, for example methanol. The sheets 14, 15 are for example made of copper.

The enclosure 16 is delimited by a lower wall 14, facing the cells 3, and an opposite upper wall 15. The walls or sheets 14, 15 are welded to each other at their periphery and spaced apart elsewhere from each other so as to delimit said internal volume 16. Spacers 17 can connect the lower wall 14 and the upper wall 15 and extend through said volume 16.

The internal surface of the enclosure may be covered, on the first wall and/or the second wall, with capillary means 18 allowing the displacement by capillary effect of the refrigerant fluid in liquid form from the condenser-forming zone 13 to the evaporator-forming zone 12.

The capillary means 18 may comprise channels formed on the internal surface of the enclosure 11. Such channels have, for example, a rectangular section. The section and/or the shape of the channels are capable of allowing such a capillary effect. Each channel may, for example, have a width and/or a depth of between hundredths and a few mm.

Said channels may be parallel to each other, at least in part.

Alternatively, the capillary means 18 may be formed by a wick covering at least part of the internal surface of the enclosure 11. Said wick may be formed by a layer 18 of sintered material, such as for example a layer of sintered powder. Said sintered material is for example of the copper type.

Alternatively, the enclosure 11 may be devoid of capillary means, the transport of liquid refrigerant from the condenser zone 13 to the evaporator zone 12 being able to be ensured by thermosiphon effect. In other words, the movement of the refrigerant is then ensured by temperature difference between the condenser zone 13 and the evaporator zone 12.

The enclosure 11 has a prismatic shape and, when viewed from above, a generally rectangular shape. The length is defined as the largest dimension of the enclosure 11 along a first axis X. The width of the enclosure 11 is defined as the second largest dimension of the enclosure along a second axis Y. The thickness of the enclosure 11 is defined as the dimension of the enclosure along a third axis Z. The first, second and third axes X, Y, Z may be orthogonal.

The first and second axes X, Y can define a plane generally parallel to the plane passing through the connectors 7, 8 or through the upper ends 6 of the cells 3. The third axis Z is parallel to the largest dimension of the cells 3, that is to say to the longitudinal axis of the cells 3.

A portion of the lower wall 14 constitutes the evaporator-forming zone 12 and is in contact and welded to two connectors 7, 8 of two adjacent cells 3, for example to an anode of a first cell 3 and to a cathode of a second cell 3. The evaporator-forming zone 12 thus ensures the electrical connection function between the corresponding electrodes or connectors 7, 8.

Thus, in a set of cells 3 connected in series, for example a row of cells 3 connected in series, the adjacent cells 3 are connected two by two via the zones forming an evaporator 12 of enclosures 11 of several cooling devices 10.

The electrical connection can be provided by the material of the corresponding wall 14 of the enclosure 11 or by an intermediate layer of electrically conductive material.

A cooling device 10 thus ensures the connection of two connectors 7, 8 of two different adjacent cells 3.

Two other cooling devices 10 can equip the connectors 7, 8 of the end cells 3 of the row. In such a case, the evaporator-forming zone 12 of each of these two devices 10 is in contact and welded to a single connector 7 or 8.

The cooling devices 10 cover the majority of all the cells 3 and are regularly distributed according to the position of the connectors 7, 8 of the cells 3.

Depending on the available space and the positions of the connectors 7, 8, the dimensions of the different speakers 11 may vary.

In the embodiment shown in , three groups of cooling devices 10 of different sizes are shown for example.

A first group 10a is made up of the two devices 10 equipping the end connectors 7, 8, not connected to other connectors. The other two groups 10b, 10c concern devices 10 each intended to electrically connect two connectors 7, 8 of two different cells 3. Thus a second group 10b comprises devices 10 whose enclosure 11 is of relatively elongated shape when viewed from above and a third group 10c comprises devices 10 whose enclosure 11 is generally square when viewed from above.

The condenser zone 13 of the enclosure 11 is constituted by the parts of the walls 14, 15 of the enclosure 11 not belonging to the evaporator zone 12. In other words, the condenser zone 13 constitutes the majority of the walls 14, 15 of the enclosure 11, and may be located both at the level of the first wall 14 and the second wall 15.

The condenser zone 13 is equipped with fins 19 formed by flat sheets 19a ( ) or by corrugated sheets 19b (figures 1, 2) whose corrugations have a rectangular or square shape.

Some parts of the corrugations are flat, in contact with said walls 14, 15 and welded to the corresponding walls 14, 15. Of course, other types of fins 19 can also be used. The fins 19 are intended to exchange heat with a heat transfer fluid external to the enclosure 11, for example air.

It will be noted that each enclosure 11 may include at least one recess 20 (figures 1 and 2) to facilitate spot welding of the enclosure 11 to the corresponding connectors 7, 8 from the side of the enclosure 11 opposite the cells 3, i.e. from above in the figures. Welding can thus be carried out in the bottom of the recess 20.

The enclosures 11 of the different devices 10 are also mounted on a common support 21 made of electrically insulating material ( ).

Said support 21 can be made of a flexible material allowing for acceptance of positioning defects of the cooling devices 10 or assembly clearances between the different cells 3.

Said support 21 may be a plastic film, for example made of polyimide.

Alternatively, said support 21 may be produced by a printed circuit. Such a printed circuit may provide other related functions, such as temperature or pressure sensors, or means for transmitting or receiving low-power signals.

In operation, heat is produced by the cell 3 and transmitted to the refrigerant fluid at the evaporator zone 12. The refrigerant fluid is then evaporated and moves to the condenser zone 13 where the calories are evacuated to the external fluid, the refrigerant fluid then being condensed and directed again to the evaporator zone 12.

Thus, each enclosure 11 forms a steam chamber operating according to the general principle of a heat pipe. Calories are thus taken at the level of the connections 7, 8 and are transmitted to the external fluid, through the refrigerant fluid.

The fact that maximizing the heat exchange surface using the fins 19 in particular makes it possible to extract sufficient calories towards the external fluid.

Claims (10)

An assembly for an electric battery comprising at least one electrical storage cell (3), said cell (3) comprising at least two electrical connection connectors (7, 8), said assembly further comprising at least one cooling device (10) comprising an enclosure (11) comprising a refrigerant fluid, said enclosure (11) comprising a zone (13) capable of forming a condenser and a zone (12) capable of forming an evaporator, the zone forming the evaporator (12) being capable of exchanging heat with at least one of the connectors (7, 8) of the cell (3), the zone forming the condenser (13) being capable of exchanging heat with a fluid external to said enclosure (11), the zone forming the condenser (13) having a heat exchange surface with the external fluid larger than the heat exchange surface with the connectors (7, 8). Assembly according to the preceding claim, comprising at least a first and a second electrical storage cell (3), the evaporator-forming zone (12) exchanging heat with a first connection (7) of the first cell (3) and with a second connection (8) of the second cell (3), said evaporator-forming zone (12) comprising at least one electrically conductive part ensuring an electrical connection between said first connection (7) of the first cell (3) and said second connection (8) of the second cell (3). Assembly according to one of the preceding claims, in which at least the evaporator zone (12) comprises cooling fins (19). Assembly according to one of the preceding claims, in which the enclosure (11) is of prismatic shape. Assembly according to one of the preceding claims, in which the evaporator-forming zone (12) is welded to each corresponding connector (7, 8). Assembly according to one of the preceding claims, characterized in that the internal surface of the enclosure (11) comprises capillary means (18) allowing the displacement by capillary effect of the refrigerant fluid in liquid form from the condenser-forming zone (13) to the evaporator-forming zone (12). Assembly according to the preceding claim, in which the capillary means (18) comprise channels formed on the internal surface of the enclosure (11). Assembly according to one of the preceding claims, comprising at least two cooling devices (10) capable of cooling connectors (7, 8) of cells (3), said devices (10) being mounted on a common support (21) made of electrically insulating material. Assembly according to one of the preceding claims, in which the refrigerant fluid is methanol. Vehicle comprising at least one assembly according to one of the preceding claims.