IT202200023418A1 - BATTERY MODULE, RELATED BATTERY PACK, AND ASSEMBLY PROCESS TO FORM SUCH BATTERY PACK - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

?BATTERY MODULE, ITS BATTERY PACK, AND THE ASSEMBLY PROCESS TO FORM SUCH BATTERY PACK?

Technical Sector of the Invention

The present invention relates to a battery module which includes a plurality of battery cells and is suitable for forming a battery pack consisting of multiple modules, in particular for the transport sector, for example for motor vehicles.

State of the Art

As is known, in the battery-powered power sector, especially in the automotive field, there is a need to cool the batteries themselves, or in general the need to maintain the battery temperature within pre-established value ranges in order to optimize performance and functionality with regard to the storage and transmission of electrical energy.

Typically, in electric or hybrid vehicles with battery packs, the latter are each formed by a plurality of storage modules arranged in positions close to each other. Each of the modules includes, in turn, a plurality of battery cells, wrapped in a sheet of steel or aluminum, and the poles of these cells are connected to each other to generate the electrical voltage foreseen in the design. Usually, the set of modules is housed in a housing structure, which may have appropriate measures to physically separate each module from the adjacent ones, so as to ensure that any fire on one of these modules does not lead to either a cascade degeneration or to the compromise of the integrity of the external walls of the housing structure.

At the same time, there is a need to provide a cooling system that is effective and allows for adequate heat exchange, without compromising the lightness and compactness requirements of vehicles.

As regards cooling, the battery pack is generally cooled by one or more channels, in which a heat exchange fluid flows. This fluid can be defined by a liquid, which in turn is cooled by the air conditioning system of the vehicle's passenger compartment, or it can be defined by the same fluid that flows in the air conditioning system. In known solutions, the channels in which the heat exchange fluid flows are arranged in correspondence with a wall that constitutes part of the housing structure mentioned above and defines the support base for the storage modules.

Solutions of this type, however, are not very satisfactory, since the amount of heat exchanged is relatively low, since it only affects the lower area of the battery cells. Furthermore, generally, the lower area is not the main source of heat in battery cells.

On the other hand, it is very important that the heat exchange is efficient since the batteries cannot tolerate temperatures above about 45?C. In particular, the heat exchange must be such as to:

- ensure rapid charging (with charging times that we want to reduce from 30 to 15 minutes), for which the battery cells must release a high thermal power;

- limit the temperature differences between the various battery cells, within 5?C, otherwise during the various recharges and subsequent use, the hotter cells tend to lose more and more effectiveness, compromising the nominal power of the battery pack,

It is therefore essential to have a cooling and heating system that is as uniform as possible between the cells, as well as efficient.

In this context, therefore, there is a need to improve the known solutions described above, in addition to providing a battery module, or storage module, that can be assembled simply and relatively quickly to form the entire battery pack.

At the same time, preferably, it is appropriate that the characteristics of the battery module and the related battery pack do not compromise the requirements of lightness and compactness normally required of vehicles, as already mentioned above.

Furthermore, there is a need to provide housing structures, even relatively complex ones, that can be built in a relatively simple way and/or with a limited number of components.

Subject and Summary of the Invention

The aim of the present invention is therefore to provide a battery module that allows the above-mentioned needs to be met in a simple and economical manner.

According to the present invention, a battery module is provided, in particular for forming a vehicle battery pack, as defined in claim 1.

The present invention further relates to a battery pack as defined in claim 10, and to an assembly process for forming a battery pack as defined in claim 12.

Brief Description of the Drawings

The invention will now be described with reference to the attached drawings, which illustrate non-limiting examples of its implementation, in which:

- figure 1 illustrates, in perspective and in a schematic and/or simplified manner, a battery pack consisting of a plurality of storage modules, made according to a preferred embodiment of the present invention;

- figure 2 shows, on an enlarged scale, one of the storage modules of figure 1; - figures 3a and 3b are enlargements, in schematic form, of a material of a casing of the storage module of figure 2;

- figure 4 is a schematic cross-section, according to the vertical section plane identified by trace IV-IV in figure 2;

- figure 5 is similar to figure 2 and shows a further embodiment of the storage module, according to the dictates of the present invention; and

- Figure 6 illustrates a detail of the embodiment of Figure 5, to show cooling channels inside the storage module.

Description of Preferred Embodiments of the Invention

In figure 1, the reference number 1 indicates, as a whole, a vehicle battery pack (partially and schematically illustrated).

The teachings reported below apply, in general, not only to the automotive and transport sector, but to any application that has the need to store electrical energy and cool the battery pack, even if this description makes explicit reference to the vehicle example.

The battery pack 1 extends in length along a rectilinear horizontal axis 6, which may correspond for example to the longitudinal direction of travel of the vehicle on which it is mounted.

The battery pack 1 comprises a plurality of rechargeable storage modules, connected to an electrical system (not illustrated) of the vehicle and indicated, each, by the reference number 10. Preferably, the modules 10 are identical to each other, in terms of shape, size and structure. A control unit, not illustrated, is configured in a known manner and not described in detail, to transfer the electric current from the storage modules 10 to the electrical system and vice versa, monitor the charge status and efficiency of the modules 10, etc.

According to one aspect of the present invention, the storage modules 10 are arranged in aligned positions adjacent to each other, i.e. they are arranged along the axis 6. In the particular example illustrated, the storage modules 10 are aligned so as to form a single row. It is not excluded that solutions having a plurality of rows of modules, parallel to each other, can be envisaged.

Each module 10 comprises a plurality of battery cells 12 (illustrated schematically in dotted lines, and not described in detail, being known per se), for example prismatic type battery cells, identical to each other in shape and size, placed side by side along a transverse direction, orthogonal to the axis 6.

With reference to the perspective view of figure 2, the following description is related to only one of the modules 10, the latter being preferably identical to each other.

Module 10 comprises an external box or casing 13 which comprises: a base wall 15, on which the battery cells 12 are supported vertically, and a perimeter wall 16, which extends upwards from a perimeter edge of wall 15, is made up of a plurality of consecutive sides, and defines the outline of a housing 18, which houses the battery cells 12. In particular, wall 15 is a quadrilateral, so wall 16 is made up of four sides.

Preferably, the casing 13 further comprises a covering wall 19 (shown in dotted line in figure 1), which closes the housing 18 from above. The wall 19 is defined by a piece distinct from the walls 15 and 16 and is superimposed on the latter as a closure, being coupled in a fixed position to an upper edge of the wall 16, and therefore allows the insertion of the battery cells 12 from above into the housing 18 during assembly.

Preferably the walls 15,16 together form a single piece.

For example, walls 15,16 are walls without through holes.

With reference to figures 3a and 3b, preferably, the set of walls 15 and 16 is obtained through an additive manufacturing technique, also known in English as "additive manufacturing", among those available: the material of the walls 15 and 16 has an internal configuration or structure designed/chosen in such a way as to combine lightness and heat exchange. According to the example in figure 3a, the material of the walls 15,16 has a reticular internal configuration or structure, also known as "lattice" in English, while in the example in figure 3b, it has an internal configuration or structure called "honeycomb". These types of internal structure and the additive manufacturing techniques allow for the optimization of the lightness requirement of the walls 15 and 16, while maintaining, in the casing 13, the necessary support, resistance, and thermal transmissibility properties to dissipate heat. Furthermore, the additive manufacturing techniques allow for a high level of flexibility. in the design choice of the shapes to be built.

According to one aspect of the present invention, the wall 16 comprises two external lateral faces 20, which are arranged on opposite sides of the housing 18 and the cells 12 and carry a respective set of conduits 22 for the flow of a heat exchange fluid, of a known type. Preferably, the conduits 22 and the wall 16 together form a single piece, made by the additive manufacturing process. Obviously, the internal structure of the material forming the conduits 22 must be continuous to ensure fluid tightness, and therefore is not of the “lattice” or “honeycomb” type, but additive manufacturing techniques allow for a high degree of flexibility in the choice of the internal structure of the material to be formed, as well as in the choice of the overall external shapes and dimensions of the various parts.

As an alternative, although not the preferred one, the ducts 22 can be made of separate pieces from the casing 13, and be fixed in contact with the faces 20 after the production of the wall 16.

The wall 16 also comprises a front face 23a and a rear face 23b, which are arranged transversely to the axis 6 and face in opposite directions to each other. In particular, the faces 23a and 23b are free of ducts. More specifically, the wall 15 is also free of ducts; at most, the ducts 22 may comprise sections of duct that extend along the two edges defined between the wall 15 and the faces 20, as in the examples illustrated.

With reference to figure 1, the faces 23a and 23b of the different modules 10 face each other, considering the row along the axis 6; the face 23a can be supported by the corresponding face 23b of the adjacent module 10, without the axial interposition of ducts or channels between the modules 10 to limit the axial dimensions of the battery pack 1.

Again with reference to figure 2, preferably, on each of the two faces 20, the ducts 22 form a respective network or mesh of channels, to have the greatest possible surface extension and therefore have a relatively high heat exchange.

The configuration of the ducts 22 on the two faces 20 is symmetrical and equal, so it will be described only for one of the two faces 20.

According to the present invention, for each face 20, the ducts 22 comprise at least one mouth 31a arranged in correspondence with the face 23a (i.e. at the front end of the casing 13) and at least one mouth 31b arranged in correspondence with the face 23b (i.e. at the rear end of the casing 13).

In the specific example illustrated, for each face 20, the ducts 22 also comprise a mouth 32a, arranged in correspondence with the face 23a and vertically spaced from the mouth 31a, and a mouth 32b, arranged in correspondence with the face 23b and vertically spaced from the mouth 31b.

According to a preferred aspect of the present invention, furthermore, the mouth 31a is arranged at the same height as the mouth 31b, in order to be more easily connected in a fluid-tight manner with the mouth 31b of another module 10 which is adjacent axially along the row of modules; similarly, the mouth 32a is arranged at the same height as the mouth 32b in order to be more easily connected with the mouth 32b of the module 10 which is adjacent axially along the row of modules.

The modules 10 may be equipped with suitable quick-connection devices, of a known type and not described in detail, arranged in correspondence with the mouths 31a and/or 31b and/or 32a and/or 32b, to connect these mouths to the ducts 22 of the adjacent modules 10, for example by means of a simple male-female axial coupling action. The quick-connection devices and/or any valves (for example non-return valves, flow control valves, regulation valves, etc.) may be integrated directly inside said mouths, or may define separate components that are added to the ducts 22 during assembly of the battery pack 1.

Preferably, on each face 20, the ducts 22 also comprise a straight section of duct 33 that joins the mouth 31a to the mouth 31b, and/or a straight section of duct 34 that joins the mouth 32a to the mouth 32b. The sections of duct 33 and 34 are spaced apart vertically and are parallel to the axis 6. The ducts 22 then comprise transverse connecting sections 35 that permanently connect the section of duct 33 with the section of duct 34, thus forming the aforementioned network of passages.

In use, preferably, the section of duct 33 serves as a delivery branch, and the section of duct 34 serves as a return branch. In particular, the mouth 31a and the mouth 31b respectively define an inlet and an outlet for the section of duct 33; and the mouths 32a and 32b respectively define an outlet and an inlet for the section of duct 34.

With reference to figure 1, for a first module 10 which is arranged at the beginning of the row of modules, the inlet defined by the mouth 31a is connected to a supply duct 36, for example via a manifold 37, to receive the heat exchange fluid. Similarly, again at the beginning of the row of modules, the outlet defined by the mouth 32a is connected to an outlet duct 38, for example via a manifold 39, to recirculate the heat exchange fluid towards a heat exchanger (not illustrated) configured so as to lower the temperature of the same fluid. Between this heat exchanger and the manifold 39, an electric pump is preferably arranged for the suction of the heat exchange fluid from the modules 10.

In the case of using the refrigerant from the vehicle's air conditioning system to define the heat exchange fluid of the battery pack, the manifold 37 is preferably coupled to an expansion valve, for example electronically controlled.

At the same time, for the last module 10 (at the end of the row of modules, i.e. at the axial end opposite to the supply duct 36) on each of the faces 20, the mouths 31b and 32b are closed, for example by means of respective caps (not illustrated) which can be added during the assembly of the battery pack 1. In this way, therefore, in the particular example illustrated, the heat exchange fluid enters and exits at the same axial end of the battery pack 1.

As mentioned above, flow control valves and/or regulation valves may be provided along the conduits 22 of the battery pack 1 to calibrate the hydraulic resistances along the circuit that is formed on each side of the battery pack 1, and therefore ensure that the heat exchange fluid also circulates in the last module 10 (at the end of the row of modules), i.e. to ensure that the heat exchange fluid is not stagnant in this last module. Suitable simulations and/or experimental tests may be appropriate to determine the amount of such hydraulic resistances at design stage.

Alternatively or in combination with the presence of valves, the passage sections of the ducts 22 are different from each other, for example progressively increasing going from one axial end to the other of the battery pack 1.

According to an alternative not illustrated, the outlet duct 38 is connected to the mouth 32b, in correspondence with the face 23b of the last module 10 (at the end of the row of modules). In this case, the mouth 32a of the first module 10 (at the beginning of the row of modules) is closed by a cap. In other words, in this case the heat exchange fluid enters and exits at opposite axial ends of the battery pack 1.

From the above, it is evident that the procedure for assembling battery pack 1 is relatively simple.

In fact, it is sufficient to arrange the modules 10 in positions aligned with each other along the axis 6, with the faces 23a and 23b of adjacent modules 10 facing each other, and couple the modules 10 to each other, connecting the mouth 31a to a corresponding mouth 31b and connecting the mouth 32a to a corresponding mouth 32b, for each of the two faces 20. In particular, the aforementioned quick-connection devices can make this connection operation even faster. Any additional connection devices, not illustrated, can be provided to constrain the face 23a to the corresponding face 23b of the adjacent module 10.

According to variants not illustrated, at least part of the wall 16 can be equipped with external fins, appendages or ribs and/or can be perforated or formed from a sufficiently rigid mesh.

Figure 5 shows a different embodiment of the battery module 10, the constituent parts of which have been indicated, where possible, by the same reference numbers used in the previous figures.

Unlike the embodiment of figure 2, the housing 18 is divided into a plurality of compartments 41, each of which houses at least one battery cell 12. In particular, the compartments 41 are separated from each other by partitions 42, which are orthogonal to the wall 15, are parallel to each other and preferably define a single piece with the walls 15 and/or 16, being made through the same additive manufacturing process.

The ducts 22, in addition to being provided externally on the faces 20, are also provided internally, on at least one of the partitions 42. Preferably, the ducts 22 are provided on all the partitions 42. For example, with reference to figure 6, each partition 42 is made up of two walls, and the ducts 22 border both walls, to exchange heat on both sides. The configuration and arrangement of the ducts 22 along the partitions 42 is similar to that described above with reference to each of the faces 20, so their description is not repeated for reasons of brevity.

From the above, it is evident that each module 10 is relatively simple to manufacture, is completely separate from the other storage modules of the battery pack 1, has an efficient heat exchange, and can be easily assembled together with the other storage modules to form the battery pack 1.

In particular, for the assembly process, it is sufficient to align the storage modules 10 along the axis 6 and connect them together at the mouths 31a, 31b, 32a, 32b, for example by means of male-female coupling actions in directions parallel to the axis 6.

In addition to the connections at the mouths 31a, 31b, 32a, 32b, other mechanical hooking and/or connection systems may be provided to constrain the walls 16 to each other at the faces 23a and 23b, and/or to constrain the walls 15 to each other.

Finally, from the above it appears evident that modifications and variations can be made to the casing 13, to the module 10, to the battery pack 1 and to the relative assembly process, described above with reference to the attached figures, which do not go beyond the scope of protection of the present invention, as defined in the attached claims.

In particular, the shape, internal material structure, and manufacturing technique of the casing 13, as well as the specific shape and arrangement of the ducts 22, may be different from those indicated by way of example.

Furthermore, the walls 19 could be absent or perforated, or a single closing cover could be foreseen, common for all the modules 10.

Claims (13)

1. Storage module (10) for forming a battery pack (1), in particular a vehicle battery pack, the storage module (10) comprising a casing, which has a longitudinal axis (6), defines a housing (18) suitable for containing a plurality of battery cells (12), and comprises: - a base wall (15) and - a perimeter wall (16), which extends from a perimeter of said base wall (15) so as to delimit said housing (18) and has or a front face (23a) and a rear face (23b), facing in opposite directions to each other and transverse to said longitudinal axis (6), and or two lateral faces (20) arranged on opposite lateral parts of said housing (18); characterised by comprising heat exchange ducts (22) arranged along said lateral faces (20); for each of said lateral faces (20), said heat exchange ducts (20) comprising a first and a second mouth (31a, 31b) arranged respectively in correspondence with said front face (23a) and said rear face (23b), suitable for defining, in use, an inlet and/or an outlet for a heat exchange fluid, and positioned in such a way as to be able to be connected, in use, to other storage modules (10) arranged in aligned and adjacent positions along said longitudinal axis (6) in said battery pack (1). 2. The storage module according to claim 1 or 2, wherein said heat exchange ducts (22), on each of said lateral faces (20), define a network of channels. 3. The storage module according to claim 1 or 2, wherein said first mouth and said second mouth, for each of said lateral faces (20), are arranged at the same height with respect to said base wall (15). 4. The storage module according to claim 3, wherein said heat exchange ducts (22) comprise, for each said lateral face (20), a straight section of duct (33) which joins said first mouth (31a) to said second mouth (31b). 5. The storage module according to any of the preceding claims, wherein said heat exchange ducts (22) comprise, for each of said lateral faces (20), a third and a fourth mouth (32a,32b) arranged respectively in correspondence with said front face (23a) and said rear face (23b) and suitable for defining, in use, an inlet and/or an outlet for a heat exchange fluid and positioned in such a way as to be able to be connected, in use, to a fourth and a third mouth (32b, 32a) forming part of said other storage modules (10). 6. The storage module according to any of the preceding claims, wherein said perimeter wall (16) and said heat exchange ducts (22) form parts of a single piece. 7. The storage module according to claim 6, wherein at least part of said perimeter wall (16) is defined by an internal structure of the honeycomb type. 8. The storage module according to claim 6, wherein at least part of said perimeter wall (16) is defined by an internal structure of the reticular type. 9. The storage module according to any of the preceding claims, wherein said heat exchange ducts (22) comprise quick connection devices at at least one of said first and second mouths (31a, 31b). 10. The storage module according to any of the preceding claims, wherein said housing (18) comprises a plurality of compartments, separated from each other by partitions (42) and each housing at least one battery cell; said heat exchange ducts (22) also being arranged along at least one of said partitions (42). 11. Battery pack (1), in particular vehicle battery pack, comprising a plurality of storage modules (10), each of which is made according to any of the preceding claims, is arranged in positions aligned with each other along said longitudinal axis (6) so that they face each other at said front and rear faces (23a, 23b), and is coupled with each other at said first and second mouths (31a, 31b) so as to be able to channel, in use, a heat exchange fluid into said heat exchange ducts (22) along said lateral faces (22). 12. The battery pack according to claim 11, wherein said storage modules (10) are identical to each other. 13. Assembly method for forming a battery pack according to claim 11 or 12, the method comprising the steps of - arrange said storage modules (10) in positions aligned with each other along said longitudinal axis (6) so that they face each other in correspondence with said front and rear faces (23a, 23b), and - coupling the storage modules which are adjacent to each other along said longitudinal axis (6), the coupling comprising a connection at said first and second mouths (31a, 31b) so as to be able to channel, in use, a heat exchange fluid into said heat exchange ducts (22) along said lateral faces (22).