Structural battery of an electric vehicle comprising a matrix of battery cells

Abstract

The present disclosure relates to an electric vehicle comprising a battery assembly (4) having battery cells (39, 40) of at least two rows (31-34) of batteries attached to a battery frame structure (30). The battery frame structure has a plurality of accommodation cavities (35, 36) arranged in a matrix form, each battery cell (39, 40) of the batteries is placed in a respective accommodation cavity (35, 36) and is connected to adjacent walls (43, 44, 45) of the respective accommodation cavity (35, 36) by a flowable adhesive substance inserted into a gap (41, 42) between the battery cell and the walls (43, 44, 45) of the respective cavity.

Description

Technical Field

[0001] This disclosure relates to an electric vehicle including a battery assembly having battery cells attached to at least two rows of batteries in a battery frame structure.

[0002] This disclosure also relates to a battery pack for such electric vehicles, and a method of manufacturing such battery components. Background Technology

[0003] Electric vehicles (also known as battery electric vehicles, or BEVs for short) use battery packs to power the drivetrain / (multiple) motors. To provide sufficient range with current battery cell technology to meet customer expectations for fossil fuel vehicles, BEV batteries are located below the passenger compartment, essentially under the floor. The overall design complexity involves maximizing the battery cell volume (range) within a given footprint (area / volume) provided by the vehicle setup to minimize weight (range / environmental impact) while maximizing highly important attributes such as crash safety and vehicle stiffness (NVH and driver experience).

[0004] Until recently, battery electric vehicle (BEV) packs were considered independent units, primarily functioning as a protective cage for battery cells and modules, preventing intrusion that could lead to catastrophic failures, while also protecting the sensitive internal electronics from external environmental influences. This idea resulted in a dual structure: the vehicle's battery and the body. If these two systems are considered as one and designed as a single system, the dual structure, with necessary clearances to allow for tolerances, typically occupies a volume that could otherwise be used to integrate more battery cells, further increasing the size. Current technology is compensating for this lower volumetric efficiency by using a larger footprint, resulting in shorter stopping distances (in both longitudinal and lateral directions) between the frame structure and the battery cell footprint. This increase in vehicle size leads to an increase in energy content.

[0005] A structural battery is known to be provided in which the battery casing forms the bottom of the vehicle body, and the conventional front floor is removed. The battery cell array is held in place within the battery pack casing by resin.

[0006] The purpose of this disclosure is to provide an electric vehicle with a battery pack having improved volumetric efficiency and forming a structural part of the vehicle body. Another purpose of this disclosure is to provide a relatively compact battery pack structure that reduces the number of components and can be manufactured efficiently. Yet another purpose of this disclosure is to provide a battery pack provided with a collision-absorbing zone that protects the battery cells from forces generated during a collision. Summary of the Invention

[0007] The electric vehicle according to this disclosure includes a battery frame structure having a plurality of receiving cavities arranged in a matrix, wherein a battery cell of each battery is placed in a corresponding receiving cavity and is connected to the adjacent wall of the corresponding receiving cavity by a flowable adhesive material inserted between the battery cell and the wall of the corresponding cavity.

[0008] The battery cells are precisely and securely positioned within a matrix structure of prefabricated housing cavities. Because the battery cells are interconnected by being firmly bonded to the cavity walls, the number of internal fastener components required to hold the battery cells in place, such as end plates, bolts, tension bands, etc., can be reduced. Compared to an equivalent modular design, this allows for a reduction in the overall battery cell footprint in the XY plane.

[0009] After the adhesive material cures, the interconnected battery cells in the matrix of the receiving cavity form a rigid and integral battery cell brick, which is easy to handle and can be accurately placed in the desired position relative to the frame or tray of the battery pack and relative to the frame components of the electric vehicle.

[0010] The battery frame structure may include longitudinal and transverse sidewalls. The sidewalls and walls of the receiving cavity may be formed by injection molding, casting, or additive manufacturing.

[0011] The battery frame structure is first formed from a flowable first material, which is then cured to harden into a solid and rigid matrix. Next, individual battery cells are inserted into their respective cavities, and the space between the battery cells and the matrix of cavities is filled with an adhesive. After the adhesive cures, the battery cells are firmly secured in place, forming a robust and rigid interconnected battery structure. This allows for reduced specifications on other frame components of the vehicle body, such as subframes, brakes, or suspensions. Once the battery cells are bonded, a single-cell composite block is formed, possessing high torsional stiffness and structural strength of the matrix of embedded battery cells. For example, if the weight of the bonded battery cells is approximately 450 kg, the peripheral structural components can achieve a 200 kg weight reduction, resulting in a total weight increase of 250 kg, where the bonded battery cells can be considered a “negative mass.”

[0012] In one embodiment, the height of the receiving cavity is substantially the same as the height of the battery cells, the bottom surface of the battery frame structure is substantially flat and supports a thermally conductive layer that contacts the bottom of each battery cell, and the top surface of the battery frame structure is positioned to contact the top cover. The bottom layer may be formed of a thermal interface material (TIM) for heat transfer from the battery cells to the bottom cooling plate. The top cover may be formed of an adhesive material and may be attached to a top plate that forms a shear plane for distributing lateral forces to the matrix of battery cells embedded in the battery.

[0013] The battery frame structure can be placed in a tray member, which includes two longitudinal side profiles interconnected by a front transverse beam and a rear transverse beam. The longitudinal sidewalls of the battery frame structure extend a certain distance from the longitudinal side members, and a compressible filler member is placed between the longitudinal sidewalls of the battery frame structure and the adjacent longitudinal side profiles.

[0014] The battery frame structure provides a rigid battery pack with a smaller lateral dimension. Weight reduction is achieved by leaving space between the battery cell frame structure and the sill member without increasing the width of the battery pack, allowing other vehicle components (suspension, brakes, chassis, wheels) to be manufactured with a lighter weight. Furthermore, deformable material between the battery cell and the sill member isolates the battery cell from the impact and provides enhanced safety against intrusion and catastrophic thermal runaway in side collisions.

[0015] The top and bottom plates can be positioned to contact the top and bottom surfaces of the battery frame structure to form a housing. These plates are attached to longitudinal profiles to form the battery pack. The battery pack can be bolted and / or bonded to the vehicle frame members in an easily operable manner.

[0016] In one embodiment, the base plate includes a plurality of cooling channels extending along its length, the cooling channels being connected to a cooling fluid inlet at a first transverse beam and to a cooling fluid outlet manifold at a second transverse beam.

[0017] The floor can be covered by an insulating layer that forms the outer bottom layer of the vehicle.

[0018] The front and rear transverse walls of the battery frame structure can contact corresponding parallel metal end plates rigidly connected to the transverse beams. The end plates suppress forces in the longitudinal direction caused by the expansion of the battery cells during aging, which can reach 10-30 kN in the example.

[0019] In one embodiment, the front panel includes a centrally located force-absorbing member, preferably formed by extrusion, having multiple chambers. The absorbing member provides a very rigid anchor point with minimal material usage and, in the event of a frontal collision, transfers the force to the bonded battery cells and sandwich structure, where the force is distributed across the bonded shear plane, thereby dispersing the load and keeping the battery cell intrusion within safe limits.

[0020] A method for manufacturing a battery assembly for an electric vehicle, comprising:

[0021] A battery frame structure with longitudinal and transverse sidewalls and including multiple receiving cavities is formed by injection molding, casting, or additive manufacturing.

[0022] The battery cells are inserted into the receiving cavity, the height of which roughly corresponds to the height of the battery components.

[0023] The space between the battery cells and the walls of the corresponding cavity is filled with adhesive material, and the battery cells of each battery are connected to the walls of the corresponding battery cells by adhesive material to form a single battery cell block.

[0024] The method may include:

[0025] A block of individual battery cells, formed by interconnected battery units, is placed in a tray member comprising two longitudinal side profiles interconnected by a front transverse beam and a rear transverse beam. The longitudinal sidewalls of the battery frame structure extend a certain distance from the longitudinal side profiles.

[0026] Deformable members are inserted between the longitudinal sidewalls of the battery frame structure and the adjacent longitudinal side profiles.

[0027] The top and bottom plates are placed on the upper and lower surfaces of the battery frame structure to form the casing, and

[0028] The shell is attached to the vehicle frame components. Attached Figure Description

[0029] Embodiments of the battery assembly according to this disclosure will be described in detail by way of non-limiting example with reference to the accompanying drawings. In the drawings:

[0030] Figure 1 The frame of an electric vehicle, including a structural battery, is shown.

[0031] Figure 2 A tray for a battery assembly according to this disclosure is shown.

[0032] Figure 3 The battery frame structure according to this disclosure is shown.

[0033] Figure 4 The battery frame structure according to this disclosure is shown.

[0034] Figure 5 It shows Figure 4 A top view showing magnified details of the battery frame structure.

[0035] Figure 6 The battery assembly is shown before the top cover is placed.

[0036] Figure 7 A battery pack according to this disclosure is shown.

[0037] Figure 8 A transverse cross-sectional view of the battery pack according to this disclosure is shown along the forward viewing direction.

[0038] Figure 9 The end plate used to reinforce the battery frame structure is shown, as well as

[0039] Figure 10 The front portion of the front frame is shown connected to the battery pack according to this disclosure via anchor brackets. Detailed Implementation

[0040] Figure 1 A frame 1 for an electric vehicle is shown, comprising a front frame structure 2 of the body-in-white, a rear floor structure 3 of the body-in-white (including a mounting or rocker arm), and a structural battery assembly 4 forming the underbody structure 5 of the vehicle. The structural battery assembly 4 includes longitudinal sill profiles 6 and 7 that interconnect the front and rear frame structures 2 and support battery packs 9 of interconnected battery cells. Crossbeams 11 and 12 are connected, for example by spot welding, to the top plate 10 of the battery pack 9 and extend laterally, interconnecting the sill profiles 6 and 7 and supporting the front passenger seats.

[0041] Figure 2 A tray 13 for the battery pack 9 is shown, having longitudinal side members 14, 15 interconnected by a front transverse beam 16 and a rear transverse beam 17. A metal base plate 18 with longitudinal cooling channels 19, 20 forms the bottom of the tray 13. A cooling inlet manifold 21 distributes cooling fluid into the channels 19, 20, and a rear outlet manifold 22 removes heated coolant from the channels and delivers it to a heat exchanger. At the front transverse beam 16, connecting brackets 24, 25 are provided to provide a rigid connection between the tray 13 and the front frame structure 2.

[0042] Figure 3A battery frame structure 30 is shown that carries four rows of battery cells 31-34. Each individual battery cell is placed in cavities 35, 36 of the battery frame structure 30 and is securely held in place by an adhesive material filling the walls of cavities 35, 36 and the space between the battery cells within the cavities. The battery frame structure 30 has longitudinal peripheral walls 37 and transverse peripheral walls 38, forming a matrix of interconnected battery cells that can be handled as a unit and precisely positioned in a tray 13. The heights of the peripheral walls 37, 38 and the cavity walls substantially correspond to the heights of the battery cells 31-34, such that the top and bottom surfaces of the battery frame structure 30 and the assembly of battery cells 31-34 are substantially planar.

[0043] Figure 4 Enlarged details of the battery frame structure 30 near the front transverse beam 16 are shown. Battery cells 39, 40 are enclosed within the walls 38, 37, 43, 44 and 37, 43, 44, 45 of corresponding cavities in the battery frame structure. The gaps 41 and 42 between the battery cells 39, 40 and the cavity walls are filled with an adhesive material, which may be formed of an adhesive material or an expanding compound, capable of flowing and filling the gaps and expanding and curing to firmly bond the battery cells to the cavity walls. The expanding compound may provide pre-compression on the individual battery cells.

[0044] Figure 5 An adhesive layer 49 is shown on top of the battery cell of the battery located in the battery frame structure 30. The space between the longitudinal side members 14, 15 and the longitudinal outer wall 37 of the battery frame structure 30 is filled with foam blocks or honeycomb structures 47, 48.

[0045] like Figure 6 As shown, the battery pack 9 is completed by placing a metal top cover 50 on the battery frame structure 30 and attaching the top cover to the adhesive layer 49 and side members 14, 15 to form a robust casing around the battery cells.

[0046] Figure 7 The battery pack 9 is shown connected to the sill profiles 6 and 7 and the transverse beams 11 and 12. In the event of a side impact at the sill profile 7, the lateral force Fs is distributed along the longitudinal side member 15 to a shear plane defined by the lower plate 18 and upper plate of the top cover 50. A deformation zone with a lateral width D is formed by the sill profile 7, the side member 15, and the foam block or honeycomb material 48. The deformation zone protects the battery cells 31-34 during a side impact and prevents cell rupture and intrusion during the impact.

[0047] Figure 8Enlarged details of the longitudinal exhaust channel 52, which extends longitudinally above the cooling channel 19 in the base plate 18, are shown. In the event of a thermal event, gas is exhausted through the exhaust channel 52 to the rear transverse beam 17, where it can escape into the environment. Because the exhaust channel 52 is cooled by the cooling channel 19 in the cooling plate 18, the risk of burn-through is significantly reduced.

[0048] A replaceable insulating layer 53 can be provided on the cooling plate 18 to form the outer layer of the vehicle. The thermal insulation provided by the layer 53 mitigates the wind chill effect on the battery pack 9 and prevents uncontrolled heat transfer. In the event of damage to the insulating layer 53, such as in the event of a road accident, it can be easily removed, inspected, repaired, or replaced.

[0049] Figure 9 A reinforcing metal end plate 55 is shown, which is attached to the transverse wall 38 and the front transverse beam 16 of the battery frame structure via anchor brackets 56 and 57. The reinforcing end plate 55 can counteract the expansion of the battery cells during aging, which generates a force of 10-30 kN on the sidewall of the transverse outer wall 38 of the battery frame structure 30.

[0050] Figure 10 The front frame component 65 of the vehicle is shown, which is attached to the anchor bracket 56 by bolts 60 and 61, and to the bracket 24 on the front transverse beam 16 by bolts 62. Frontal impact force F f The load is deflected downwards to the anchor bracket 56. The anchor bracket 56 is arc-welded to the end plate 55 and has multiple bonded shear planes that distribute the load across the surface of the anchor bracket across the end plate 55, thereby keeping intrusion into the battery cells of the battery in the battery frame structure within safe limits.

Claims

1. An electric vehicle including a battery assembly having battery cells attached to at least two rows of batteries in a battery frame structure, wherein the battery frame structure includes a plurality of receiving cavities arranged in a matrix, wherein the battery cells of each battery are placed in a respective receiving cavity and connected to adjacent walls of the respective receiving cavity by a flowable adhesive material inserted into a gap between the battery cells and the walls of the respective cavity.

2. The electric vehicle according to claim 1, wherein, The battery frame structure includes a longitudinal outer wall and a transverse outer wall, and the longitudinal outer wall, the transverse outer wall and the wall of the receiving cavity are formed by injection molding, casting or additive manufacturing of a first cured material.

3. The electric vehicle according to claim 1 or 2, wherein, The height of the receiving cavity is substantially the same as the height of the battery cell of the battery. The bottom surface of the battery frame structure is substantially flat and supports the base plate that contacts the bottom of the battery cell of each battery. The top surface of the battery frame structure is positioned to contact the top cover.

4. The electric vehicle according to claim 1 or 2, wherein, The battery frame structure is placed in a tray member, the tray member including two longitudinal side profiles interconnected by a front transverse beam and a rear transverse beam, the longitudinal outer wall of the battery frame structure extending a distance from the longitudinal side profiles, and a compressible filler member placed between the longitudinal outer wall of the battery frame structure and the corresponding adjacent longitudinal side profile.

5. The electric vehicle according to claim 4, wherein the top plate and the bottom plate are positioned to contact the top and bottom surfaces of the battery frame structure, and the top plate and the bottom plate are attached to the longitudinal side profile forming the housing.

6. The electric vehicle according to claim 5, wherein the floor includes a plurality of cooling channels extending along the length direction, the cooling channels being connected to a cooling fluid inlet manifold at the front transverse beam and to a cooling fluid outlet manifold at the rear transverse beam.

7. The electric vehicle according to claim 6, wherein the floor is covered by an insulating layer, the insulating layer forming the outer bottom layer of the vehicle.

8. The electric vehicle according to claim 5, wherein the front transverse outer wall and the rear transverse outer wall of the battery frame structure contact corresponding parallel metal reinforcing plates, the parallel metal reinforcing plates contacting the front transverse outer wall and the rear transverse outer wall and connected to the front transverse beam and the rear transverse beam along their width direction.

9. The electric vehicle according to claim 8, wherein the front parallel metal reinforcing plate includes a centrally located reinforcing member formed by extrusion and has a plurality of compartments.

10. A battery assembly for an electric vehicle, comprising battery cells having at least two rows of batteries attached to a battery frame structure having a plurality of receiving cavities arranged in a matrix, wherein a battery cell of each battery is placed in a corresponding receiving cavity and connected to an adjacent wall of the corresponding receiving cavity by a flowable adhesive material inserted into a gap between the battery cell and the wall of the corresponding cavity, the battery frame structure being placed in a tray member comprising two longitudinal side profiles interconnected by a front transverse beam and a rear transverse beam, wherein a longitudinal peripheral wall of the battery frame structure extends a distance from the longitudinal side profiles, and a compressible filler member is placed between the longitudinal peripheral wall of the battery frame structure and the adjacent longitudinal side profiles.

11. A method for manufacturing a battery assembly for an electric vehicle, comprising: A battery frame structure is formed, the battery frame structure having longitudinal peripheral walls and transverse peripheral walls, and including multiple receiving cavities arranged in a matrix form by injection molding, casting, or additive manufacturing. Insert the battery cells into the receiving cavity, and The gap between the battery cell and the wall of the corresponding cavity is filled with a flowable adhesive material, and the battery cell of each battery is connected to the wall of the corresponding cavity through the flowable adhesive material to form a single battery cell block.

12. The method of claim 11, comprising: The individual battery cell block, formed by the battery frame structure and the connected battery cells, is placed in a tray member, the tray member including two longitudinal side profiles interconnected by a front transverse beam and a rear transverse beam, the longitudinal outer wall of the battery frame structure extending a distance from the longitudinal side profiles. A compressible filler member is inserted between the longitudinal outer wall of the battery frame structure and the adjacent longitudinal side profile. The top plate and bottom plate are placed on the top and bottom surfaces of the battery frame structure.

13. The method of claim 12, further comprising attaching the top plate and the bottom plate to the vehicle frame.

14. The method according to claim 12 or 13, further comprising connecting the top plate and the bottom plate to longitudinal side profiles to form a housing.

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