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EP-4434787-B1 - VEHICULAR BATTERY PACK AND RELATED ASSEMBLY METHOD

EP4434787B1EP 4434787 B1EP4434787 B1EP 4434787B1EP-4434787-B1

Inventors

  • FAVARETTO, FABRIZIO

Dates

Publication Date
20260506
Application Date
20240319

Claims (13)

  1. A vehicular battery pack (9) comprising: - a support structure (11) extending along a vehicular longitudinal axis (X) and comprising a floor (12) configured to define, at least in part, a floor pan (10) of a road vehicle (1); the floor (12) having a board-like conformation comprising an inner surface (13) and an outer surface (14), opposite the inner surface (13) and configured to be externally exposed so as to face the ground (G); the support structure (11) defining within it a housing (15) limited inferiorly by said floor (12); - cylindrical electrochemical cells (16), electrically connected to each other and arranged internally on the inner surface of said housing; each of the cylindrical electrochemical cells (16) comprises a lateral surface (17) having a circular cross-section extending along an axis (A) of symmetry and two planar bases (18), which are crossed by said axis (A) of symmetry; the vehicular battery pack (9) being characterised in that the floor (12) of the support structure (11) has an at least partially curved conformation, which deflects distancing itself from the ground (G) along the longitudinal axis (X) in a direction opposite a normal travel direction (D) of the road vehicle (1); wherein said cylindrical electrochemical cells (16) are at least partially arranged side by side and with their respective axes of symmetry parallel to each other; wherein said electrochemical cells (16) are arranged with said respective lateral surface (17) in contact with the inner surface (13) of the floor (12), so as to form one or more strips (19) of electrochemical cells (16) parallel to each other and to the at least partially curved conformation of the floor (12) of the support structure (11); wherein the floor (12) comprises, along the longitudinal axis (X), a front portion (20) substantially parallel to the ground (G) and a rear portion (21) diverging from the ground (G), both planar, which are connected by a curved portion (22); the one or more strips (19) of parallel electrochemical cells (16) extending from the front portion (20) to the rear portion (21), and having at least the lateral surface (17) of one electrochemical cell of the one or more strips (19) in contact with the curved portion (22).
  2. The battery pack (9) according to claim 1, and comprising a plurality of strips (19) of electrochemical cells (16) parallel to each other, the strips (19) forming a first layer (23) covering at least for the most part the available inner surface (13) of the floor (12).
  3. The battery pack (9) according to claim 2 and comprising further layers (24) of strips (19) of electrochemical cells (16) at least partially overlapping the first layer (23) and whose cells (16) are arranged to form a quincunx formation with the cylindrical cells (16) of the first layer (23).
  4. The battery pack (9) according to claim 3, and comprising a verticalized portion (25), supported by the rear portion (21) and having a thickness (W') greater than the rest of the battery pack (9), in which there are at least three, in particular at least five further overlapping layers (24).
  5. The battery pack (9) according to claim 4 and comprising a lowered portion (27), supported by the front portion (20) and having a thickness (W") less than the verticalized portion (25), in which the first layer (23) or the first layer (23) with a single further layer (24) overlapping it are present.
  6. The battery pack (9) according to any one of claims 2 to 5, wherein the cells (16) of a first strip (19) of the plurality of strips (19) have length (L'), along the longitudinal axis (X), different from the cells (16) of a second strip (19) of the plurality of strips (19).
  7. The battery pack (9) according to any one of the preceding claims, wherein the cylindrical cells (16) of a same strip (19) have different lengths.
  8. The battery pack (9) according to claim 7, wherein the cylindrical cells (16) having different lengths are arranged to have, each, one of the two planar bases (18) of each of the cells (16) on a same feed plane.
  9. Electric or hybrid road vehicle (1) comprising: - four wheels (2, 3), of which at least one pair of driving wheels (2, 3); - a passenger compartment (6); - a power train configured to control the motion of the driving wheels (2, 3); - a battery pack (9) according to any one of claims 1 to 8 mounted to a chassis of the road vehicle (1) and arranged so as to define at least part of a floor pan (10) of the road vehicle (1).
  10. A method of assembling a vehicular battery pack (9) of any of the claims 1-8 comprising the steps of: - fabricating in metal plate or composite material a support structure (11) extending along a vehicular longitudinal axis (X) and comprising a floor (12) configured to define, at least in part, a floor pan (10) of a road vehicle (1); the floor (12) having a board-like conformation comprising an inner surface (13) and an outer surface (14), opposite the inner surface (13) and configured to be exposed externally so as to face the ground (G); the support structure (11) defining within it a housing (15) limited inferiorly by said floor (12); wherein the floor (12) of the support structure (11) has an at least partially curved conformation, which deflects away from the ground (G) along the longitudinal axis (X) in a direction opposite a normal travel direction (D) of the road vehicle (1); - arranging cylindrical electrochemical cells (16), electrically connected to each other, inside said housing, in correspondence with the inner surface; wherein each of the cylindrical electrochemical cells (16) comprises a lateral surface (17) with circular cross-section extending along an axis (A) of symmetry and two planar bases (18), which are crossed by said axis (A) of symmetry; wherein said cylindrical electrochemical cells (16) are at least partially arranged side by side and with their respective axes of symmetry parallel to each other; the method being characterised in that, during the arranging step, said electrochemical cells (16) are arranged with said respective lateral surface (17) in contact with the inner surface (13) of the floor (12), so as to form one or more strips (19) of electrochemical cells (16) parallel to each other and to the at least partially curved conformation of the floor (12) of the support structure (11).
  11. The method according to claim 10, wherein, during the arranging step, said electrochemical cells (16) are arranged so as to form a first layer (23) covering at least for the most part the available inner surface (13) of the floor (12).
  12. The method according to claim 11 and comprising the further step of arranging further layers (24) of strips (19) of electrochemical cells (16) at least partially overlapping the first layer (23) and the cells (16) of which are arranged so as to form a quincunx formation with the cylindrical cells (16) of the first layer (23).
  13. The method according to claim 12, wherein, during the further arranging step, a verticalized portion (25) is formed, supported by the rear portion (21) and having a thickness (W') greater than the rest of the battery pack (9); in the verticalized portion (25) at least three, in particular at least five, further overlapping layers (24) are arranged.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This invention claims priority from Italian patent application no. 102023000005253 filed on March 21, 2023. TECHNICAL FIELD The present invention refers to the field of the energy storage systems in the automotive sector and relates to a vehicular battery pack and to a related assembly method. In particular, the present invention is advantageously, but not exclusively applied to battery packs for high-performance road vehicles, to which the following description will explicitly refer without thereby losing generality. PRIOR ART Lithium batteries in relation to their high energy density increasingly allow the implementation of the electric power in the automotive sector. Lithium polymers, in particular, currently represent, from the electrochemical point of view, the state of the art in the production of high-capacity batteries. Solutions are known which provide for the interconnection in series and in parallel of several cells (generally, each one of 3.7 V) for reaching the target total voltage and energy density for a vehicular battery pack. Various types of vehicular battery packs are known mainly comprising cylindrical or planar (prismatic or pocketed, so-called pouch) batteries. The batteries are generally anchored to the floor (floor pan) of the vehicle. In some cases, the batteries are housed in the same floor pan, in other cases, they are arranged in place of a traditional heat power train assembly. Patent document EP3674122 describes a battery pack in which the battery modules are made of a plurality of cylindrical batteries arranged parallel to each other and with their longitudinal axis (i.e. the axis of rotation around which the jelly-roll forming the cylindrical cell of each battery is formed) perpendicular to the floor pan. Alternatively, the battery modules usually available on the market (not only the automotive market, but also the consumer electronics market) often consist of planar pouch batteries, which have a very limited thickness with respect to the other dimensions. Two very wide opposite faces (through which the heat is almost integrally dissipated) are identified and four thin elongated sides are identified, wherein on one or on two opposite sides, the positive and negative terminals of the cell are arranged. In any case, the battery packs according to the prior art are configured to have the lower surface flat, and hence the batteries contained therein direct to the ground a flat surface (for example one of the main faces of the planar batteries or the base of the cylindrical batteries). For high-performance vehicles, it is preferable to have a conformation of the lower part of the chassis of the vehicle such to satisfy predetermined mechanical and aerodynamic requirements. In accordance with what described by European patent EP3674122, road vehicles are known comprising a floor pan divided into two planar portions, a front one and a rear one, joined transversally, wherein the front portion is parallel to the ground and the rear portion determines a progressive moving away from the ground towards the rear of the road vehicle. In particular, the front planar portion and the rear planar portion are inclined with respect to each other by an angle less than 5°. However, the presence of such angle causes disadvantages from the aerodynamic point of view. In particular, the angle of the floor pan represents an unevenness which leads the fluid vein to detach from the bottom of the vehicle, thus reducing the rear aerodynamic load (contrary to what desired). Simultaneously, though, the planarity of the floor pan is made necessary by the presence of the battery modules, which are usually provided with planar surfaces and, in order to prevent wasting large amounts of space, need a planar support. The need is thus felt to optimize the aerodynamics of the road vehicle without wasting useful space for the batteries. Document FR2868387A1 describes a moped having electric propulsion which operates utilizing a battery provided with a plurality of cylindrical cells. Document US2020207201A1 describes an electric or hybrid sports car which comprises a battery pack which incorporates at least one structural element of the chassis of the vehicle, wherein such structural element can be removed from the chassis of the vehicle only together with the battery pack. DESCRIPTION OF THE INVENTION The object of the present invention is to provide a vehicular battery pack and a related assembly method, and a related vehicle which are at least partially exempt from the drawbacks described above and, simultaneously, are simple and cost-effective to fabricate. According to the present invention, a vehicular battery pack and a related assembly method, and a related vehicle are provided according to what claimed in the following independent claims and, preferably, in any one of the claims directly or indirectly dependent on the independent claims. The claims describe preferred em