Electric battery pack, with forced air flow thermoregulation system

Description

DESCRIPTION of the industrial invention entitled: “Electric battery pack, with forced flow thermoregulation system of air", by: CRF Consortium Company, Italian nationality, Strada Torino, 50 - 10043 Orbassano (TO). Designated inventors: Raffaele RICCO; Nicolas BERTIER. Filed on: **** DESCRIPTION TEXT Field of invention The present invention relates to the field of electric batteries, in in particular to electric batteries for powering electric traction motors for electric or hybrid vehicles. More specifically, the invention relates to battery packs equipped with of an air thermoregulation system. Background of the invention In general, it is of fundamental importance to ensure that during the use of an electric vehicle, the battery cells are always located at a temperature contained within a predetermined range, typically between a minimum threshold of 20° C and a maximum threshold of 55° C. The battery cells used in electric vehicles are typically lithium-ion battery cells, which tend to develop heat as a result of the chemical reaction that takes place inside the battery cell during operation, and also for the effect Joule due to the passage of current inside the battery. With the term "battery operation" here means both the charging process of the battery, both the discharge process, which typically occurs while driving of the vehicle. It should be noted that the most critical conditions of battery operation, which carries a risk of overheating of the cells, are those related to the fast charging process, that is to say battery charging in less than an hour, and those relating to a fast discharge process. A particular case of fast discharge is when the vehicle is used to provide electricity to a home, acting as a energy accumulator not for traction, but for domestic use. Numerous Electric vehicle models include this feature. During normal operating conditions of the battery pack, it is it is necessary to have a thermoregulation system capable of carrying out a cooling action, to counteract the increase in temperature due to the heat that develops in the cells for the reasons indicated above. On the contrary, in the for example, in the case of activation of the vehicle's electric motor after a stop prolonged at a very low ambient temperature, it is necessary to have a thermoregulation system capable of performing a heating action. A first type of solutions known in this field involves the use of a thermoregulation system configured to supply a flow of air to controlled temperature inside the battery pack container, so the air flow comes into direct contact with the battery cells (see, for example, (US 2016 / 211560 A1 and US 2016 / 211561 A1). These solutions have However, they proved to be completely unsatisfactory, mainly because the air can cause corrosion of the terminals, or “tabs” of the battery cells and the casing of individual cells. A second type of known solutions includes a thermoregulation system immersion, where the battery cells are in direct contact with a flow of a temperature-regulating liquid (see for example document DE 1020 / 21120074 A1). These solutions are, however, relatively complex and expensive, even for the need to prepare a circuit for the thermoregulation liquid, with tank, pump and heat exchangers. Furthermore, the thermoregulation systems of this type further increase the weight of a vehicle's drive system electric, which is in itself relatively high due to the weight of the battery pack. Another problem encountered in the application of battery packs in electric vehicles it is due to the need to find adequate space inside the vehicle. The Applicant has already proposed several solutions in the above field indicated. See for example the Italian patent applications 102023000022692, 102023000022698, 102023000022704, 102023000025884, 102024000002776, 102024000002779, 102024000004423, 102024000007807, 102024000007813, 102024000007816, 102024000007828, 102024000013039, 102024000013492, 102024000014308, 102024000014314, 102024000014326, 102024000015637, 102024000016354, 102024000016933, all still not available to the public on the priority date of the present invention. Figure 1 of the attached drawings shows a typical solution, where the package battery, indicated with 1 in the figure, is located under the floor of the motor vehicle and extends over a prevalent portion of the floor underneath of the front seats and rear seats of the motor vehicle (figure 1 illustrates, for simplicity, the driver and a rear passenger, without illustrating the seats). the above solution involves an increase in the height H of the vehicle, which It also translates into an increase in the aerodynamic drag coefficient (Cx) of the motor vehicle. One possible solution to the above problem is to adopt a battery pack of different configurations, suitable to be contained in space underneath the rear seats of the motor vehicle, as illustrated in figure 2. This solution however requires increasing the battery efficiency and increasing in particular the efficiency of the thermoregulation system. The present invention stems from these needs. Purpose of the invention It is therefore an object of the present invention to to create an electric battery pack equipped with a thermoregulation system perfected, highly efficient, yet simple in construction, light and above all takes up minimal space. Summary of the invention In order to achieve the above-mentioned aim, the invention has as its object a electric battery pack, including: - a plurality of battery cell groups, - in which the cells of each group are placed side by side along a first horizontal direction, - in which the different groups of battery cells are placed side by side in said first horizontal direction and / or in a second horizontal direction orthogonal to the first horizontal direction, - in which the battery cell groups are arranged within a container inside of the battery pack, surrounded by an outer battery pack container drums, - where the inner container has an upper wall), a lower wall, two end walls parallel to said first horizontal direction and two walls laterals parallel to said second horizontal direction, - where the outer container has an upper wall, a lower wall, two end walls parallel to said first horizontal direction and two walls laterals parallel to said second horizontal direction, - where between the walls of the outer container and the walls of the container internal passages are defined for a flow of thermoregulating air, communicating with an inlet opening for the thermoregulation air flow formed in one end wall of the outer container of the battery pack, and a thermoregulating air flow outlet opening formed in the wall opposite end of the outer container of the battery pack, - in which the aforementioned passages for the flow of thermoregulating air include: - an upper passage, between the upper wall of the container exterior of the battery pack and the upper wall of the internal container of the battery pack, - a lower passage, between the lower wall of the outer container of the battery pack and the bottom wall of the internal container of the battery pack drums, - a front passage, formed between the end wall of the external container having said entrance opening and the adjacent wall end of the internal container of the battery pack, - a rear passage, formed between the end wall of the external container having said outlet opening and the adjacent wall end of the internal container of the battery pack, - wherein the battery pack includes at least one adjacent fan to the said outlet opening, to force a flow of thermoregulating air from said inlet opening to said outlet opening through the passage front, the upper and lower passages, and the rear passage, - said front passage and said rear passage being configured in such a way that the flow of thermoregulating air comes into contact with a prevalent portion of said end walls of the internal container of the battery pack. In the battery pack according to the invention, a thermoregulation efficiency of the cells is achieved thanks to the forced flow of air which is activated by one or more fans directly associated with the battery pack and thanks to the fact that the air flow is guided in such a way as to touch a prevalent portion of the walls of the internal container of the battery pack. At the same time, a contact direct contact between the air flow and the battery cells is avoided, which solves the root cause the problem related to the risk of oxidation of the poles and the cell casing. In a preferred embodiment, the battery pack comprises an additional fan adjacent to said inlet opening and arranged in a chamber defined between the outer container and the inner container. This fan is preferably in series with a HVAC cold air generation system located at the front of the vehicle. Preferably, in order to maintain the vertical dimension of the package of very small battery, the battery cells are arranged horizontally horizontally (especially if the cells are pouch or prismatic type, with a very thin and long configuration), each with its respective positive and negative poles negative arranged on a vertical surface at the end of the cell, adjacent to one or the other of said end walls of the internal container of the pack of battery. The defined passages between the internal container and the external container are configured in such a way as to ensure that a predominant portion of the walls of end of the inner container is covered by the air flow of thermoregulation, which allows for high thermoregulation efficiency of the cell poles, which are located adjacent to the said end walls of the internal container. In one variant, the space inside the inner container that is not occupied from the battery cells is filled with a dielectric liquid (e.g. an oil dielectric), which improves the heat exchange between the walls of the internal container and the battery cells. The present invention also relates to an electric motor vehicle or hybrid, equipped with the battery pack described above. In one example, the opening of inlet for the flow of thermoregulating air that is formed on the wall front of the external container of the battery pack is in communication with a automotive HVAC system. In one example, the battery pack is contained in a space below the rear seats of the motor vehicle. Detailed description of the invention Further features and advantages of the present invention will be from the following description with reference to the attached drawings, provided for illustrative purposes only as a non-limiting example, where: Figures 1, 2 are schematic cross-sectional views of a motor vehicle, which show two different solutions for housing the battery pack, Figure 3 is a schematic perspective view of a system of air thermoregulation studied by the Applicant previously to the present invention, Figure 4 is a schematic cross-sectional view of a battery pack according to the invention, and Figure 5 is a schematic sectional view referring to a variant relating to a battery pack with cylindrical cells. Figures 1, 2 have already been described above. As indicated, one of the advantages of the present invention is to allow the production of a package highly efficient battery, with an effective thermoregulation system, suitable to be contained in a relatively limited space, under the seats rear of a motor vehicle (as shown in figure 2). It is evident, however, that the invention is of general application and can be used to make battery packs of any shape and size arranged in the vehicle. Figure 3 schematically illustrates the general characteristics of a air-operated thermoregulation system, of a type that has been studied by the Applicant prior to the present invention. The number of reference 1 indicates the battery pack as a whole, which includes a external container 2, inside which an internal container 3 is placed, in which several groups of battery cells are housed. Between the container external 2, which can be made of metal or plastic material, and the internal container 3, which is for example made of dielectric plastic material, and defined a thermoregulation shirt 4, which is crossed by a flow of air at controlled temperature. The solution illustrated in figure 3 includes two layers of battery cell groups. Each layer comprises battery cell groups of Prismatic type. The battery cells of each group are placed side by side along a horizontal direction X. Furthermore, each layer of battery cells includes several groups of cells placed side by side both in the X direction and in a horizontal direction Y orthogonal to the X direction. In the case of the solution previously studied by the Applicant, illustrated in figure 3, the thermoregulation jacket 4 communicates via a portion of duct 5, having a divergent configuration in the direction of the battery pack 1, with an additional conduit 6 connected to the system HVAC ("Heating, Ventilation and Air Conditioning") air conditioning of a hybrid electric vehicle on which the battery pack is installed. In the previously studied solution, illustrated in figure 3, it was a fan 7 is foreseen, placed in the duct 6, upstream of the portion of duct 5, to activate the air flow. A door 6A was also provided in a part of the duct 6 which could be opened to connect the internal cavity of the duct 6 with the external environment. Still with reference to the previously studied solution, the air flow fed through the portion of duct 5 provided for a passage 8 of the thermoregulation air flow both above the inner container, both below the inner container, and in a space formed between two overlapping layers of battery cell clusters. Starting from the solution previously studied and illustrated in the figure 3, the Applicant has come to realize the battery pack according to this invention. An example of implementation of the battery pack according to the invention is illustrated in figure 4, which represents a sectional view of the battery pack in a plane orthogonal to the horizontal direction X. In figure 4, the parts common to those in figure 3 are indicated by the same references The solution illustrated in figure 4 involves a single layer of cells drums. The battery cells of the battery pack according to the invention, indicated by reference 9 in figure 4, are prismatic type battery cells, having each a casing with two opposite main surfaces, arranged orthogonally to the horizontal direction X, two horizontal end surfaces and two vertical end surfaces. As visible in figure 4, in the preferred implementation example, they are two groups of 9 cells are planned side by side along the Y direction, with the positive and negative poles negative P, N of the cells facing opposite sides. With reference to figure 4, in order to maintain the vertical dimension of the very compact battery pack, the battery cells are arranged horizontally horizontally, each with the respective positive and negative poles P, N arranged on a vertical end surface of the cell. The two groups of cells 9 are arranged inside an internal container 3, having an upper wall 30, a lower wall 31, two end walls 32, 33 orthogonal to the Y direction, and two side walls orthogonal to the X direction (not visible in figure 4). The external container 2 of the battery pack 1 also comprises a upper wall 20, a lower wall 21, a front end wall 22, in which an opening 220 is formed for the inlet of the air flow of thermoregulation, a rear end wall 23, having an opening of 230 outlet for the thermoregulation air flow outlet and two side walls orthogonal to the X direction, not visible in figure 4. As also illustrated in figure 4, between the external container 2 and the internal container 3 are defined the passages for the air flow of thermoregulation that connects the 220 input opening to the output opening 230. The passages for the thermoregulation air flow include, in particular, an upper passage A, formed between the upper wall 20 of the outer container 2 and the upper wall 30 of the inner container 3 which is it faces, a passage B between the lower wall 21 of the external container and the lower wall 31 facing it, of the internal container 3; a passage C, formed between the end front wall 22 of the outer container and the wall end 32 of the internal container 3 facing it; a passage D between the rear end wall 23 of the outer container 2 and the end wall 33 facing it of the internal container 3. According to the invention, passages A, B, C, D, are configured so that the flow of air from the inlet opening 220 reaches the opening of exit 230 after having grazed a prevalent portion of the end wall front 32 of the internal container 3, the upper and lower walls 30, 31 of the internal container 3, and a prevalent portion of the rear wall 33 of the internal container 3. In this way, a high efficiency of the action is achieved thermoregulation, especially at the end walls 32, 33 of the internal container 3, which are adjacent to the positive and negative poles P, N of all 9 cells, that is, the area subject to the highest temperature variations. The fluid entering from opening 220 may be hot (i.e. it may have a temperature above 20°C) in case it is necessary to pre-heat the package battery or it may be cold (i.e. it may have a temperature lower than 25°C) if you want to cool the battery pack (for example during a fast charging). Heat exchange occurs thanks to the direct contact of the faces lower and rear of the cells with walls 30 and 31; To compensate for the surface irregularities of the cells or walls 30 and 31 can be interposed a (electrically insulating) thermally conductive paste of a known type. The faces cells containing the poles cannot be in direct contact with the walls 32 and 33 to avoid short circuits (unless a material is interposed electrically insulating but thermally conductive, for example a paste known type or a PCM): however also the walls 32 and 33, simply as to direct contact with the walls 30 and 31, are designed to dissipate heat and therefore they deserve to be cooled or reheated. According to a further essential feature of the invention, the package battery comprises at least one fan V, adjacent to the outlet opening 230, configured to draw airflow out of battery pack 1. THE Preferably, the battery pack also includes an additional V fan, arranged in a chamber 40 formed between the facing walls 22, 32 of the external container 2 and internal container 3, and configured to suck the air flow from the inlet opening 220 and push it towards the outlet opening 230. As is evident from the above description, the battery pack according to the invention, it is characterized by a series of important advantages. The package battery can be configured to have a very low height, thanks to the arrangement of the battery cells with the electrodes facing the front and rear end surfaces of the inner container of the pack battery. The flow of thermoregulation air does not come into direct contact with the battery cells, which solves the problem of oxidation of the electrodes and the battery cell casing. The preparation of one or more fans in the battery pack ensures that a forced flow of air is obtained thermoregulation, which allows to significantly increase the capacity of heat exchange. Furthermore, the passages for the air flow, defined between the container external the internal container of the battery pack, are configured in such a way to force the flow of thermoregulation air to touch a portion prevailing of the front and rear end surfaces of the internal container of the battery pack, which increases the thermoregulation efficiency right in the areas where the battery cell electrodes are preferably located. As indicated, in one variant the internal space of the internal container 3 which is not occupied by the battery cells 9 is filled with a dielectric liquid, for example a dielectric oil, in order to increase the efficiency of the exchange thermal between the walls of the internal container 3 and the battery cells 9. Alternatively A phase change material (PCM) can be used instead of the dielectric liquid of any type known to be used for electronic applications. The invention is particularly suitable for the creation of a package of battery of relatively small dimensions, suitable for being housed in a space beneath the rear seats of a motor vehicle, as illustrated in the figure 2. However, the invention is applicable to any battery pack configuration and any arrangement of the battery pack within the motor vehicle. For example, the invention is also applicable to the case in which the cells of battery 9 are of cylindrical type and are arranged in several overlapping layers, each layer including multiple rows of horizontally arranged cylindrical cells (see the figure 5, which schematically shows only cells 9 and walls 30 and 31 of the internal container). In this case it is necessary to avoid contact between the poles of each single cell with container walls 30, 31, 32, 33 to avoid short circuits. To optimize the contact of the cylindrical surfaces of the cells with the walls, it is possible think of making the walls with a shape of the type illustrated in the figure in contact with the cells with cylindrical geometry, so as to maximize the contact. Cylindrical cells can also be arranged vertically, in the in which case the walls 30, 31 are flat. Naturally, without prejudice to the principle of the invention, the details of construction and forms of implementation may vary widely from as described and illustrated purely by way of example, without thereby departing from the scope of the present invention.

Claims

1. Electric battery pack (1), comprising: - a plurality of battery cell groups (9), - wherein the cells (9) of each group are arranged side by side along a first horizontal direction (X), - wherein the different battery cell groups are arranged side by side in said first horizontal direction and / or in a second horizontal direction (Y) orthogonal to the first horizontal direction (X), - wherein the battery cell groups (9) are arranged within an internal battery pack container (3), surrounded by an external battery pack container (2), - wherein the internal container (3) has an upper wall (30), a lower wall (31), two end walls (32, 33) parallel to said first horizontal direction (X) and two side walls parallel to said second horizontal direction (Y), - wherein the external container (2) has an upper wall (20), a lower wall (21), two end walls (22, 23) parallel to said first horizontal direction (X) and two side walls parallel to said second horizontal direction (Y),23) parallel to said first horizontal direction (X) and two side walls parallel to said second horizontal direction (Y), - wherein between the walls (20-23) of the outer container (2) and the walls (30-33) of the inner container (3) are defined passages (A, B, C, D) for a flow of thermoregulating air, communicating with an inlet opening (220) of the flow of thermoregulating air formed in an end wall (22) of the outer container (2) of the battery pack, and an outlet opening (230) of the flow of thermoregulating air formed in the opposite end wall of the outer container (2) of the battery pack, - wherein the said passages for the flow of thermoregulating air comprise: - an upper passage (A), between the upper wall (20) of the outer container (2) of the battery pack and the upper wall (30) of the inner container (3) of the battery pack, - a lower passage (B),between the lower wall (21) of the outer container (2) of the battery pack and the lower wall (31) of the inner container (3) of the battery pack, - a front passage (C), formed between the end wall (22) of the outer container (2) having said inlet opening (220) and the adjacent end wall (32) of the inner container (3) of the battery pack, - a rear passage (D), formed between the end wall (23) of the outer container (2) having said outlet opening (230) and the adjacent end wall (33) of the inner container (3) of the battery pack, - wherein the battery pack comprises at least one fan (V) adjacent to said outlet opening (230), for forcing a flow of thermoregulating air from said inlet opening (220) to said outlet opening (230) through the front passage (C), the upper and lower passages (A, B), and the rear passage (D),- said front passage (C) and said rear passage (D) being configured in such a way that the flow of thermoregulating air comes into contact with a prevalent portion of said end walls (32, 33) of the internal container of the battery pack., 2. Battery pack according to claim 1, characterised in that it comprises a further fan (VI) adjacent to said inlet opening (220) and arranged in a chamber (40) defined between the external container (2) and the internal container (3) 3. Battery pack according to claim 1, characterised in that the battery cells (9) are arranged horizontally, each with the respective positive and negative poles (P, N) arranged on a vertical end surface of the cell, adjacent to one or the other of said end walls (32, 33) of the internal container (3) of the battery pack (1).

4. Battery pack according to claim 1, characterised in that the space inside the internal container (3) which is not occupied by the battery cells (9) is filled with a dielectric liquid.

5. Battery pack according to claim 1, characterised in that the battery cells (9) are cylindrical cells arranged horizontally in several superimposed layers, each layer having several parallel rows of cells, and in which the upper and lower walls (30, 31) of the internal container (3) have a shape that follows the profile of the cells adjacent to them.

6. Battery pack according to claim 1, characterised in that the battery cells (9) are vertically arranged cylindrical cells and in which the upper and lower walls (30, 31) of the internal container (3) are flat walls.

7. Electric or hybrid motor vehicle, characterised in that it comprises an electric battery pack according to any of the preceding claims.

8. Motor vehicle according to claim 7, characterised in that the inlet opening (220) on the front wall (22) of the external container (2) of the battery pack is in communication with an HVAC system of the motor vehicle.

9. Motor vehicle according to claim 7, characterised in that the battery pack (1) is contained in a space underneath the rear seats of the motor vehicle.