Method for mounting a battery system to the frame of an electric vehicle

Abstract

A method for mounting a battery system to the chassis floor of an electric vehicle, wherein the battery system is adapted to provide power to drive the rolling motion of the electric vehicle, and wherein a plane extends through and parallel to the chassis floor, a first side of the plane facing downwards during use of the electric vehicle, the method comprising: securing a plurality of battery modules to the chassis floor on the first side of the plane, each battery module including electrical terminals; subsequently electrically connecting the electrical terminals of the battery modules to each other to form a battery system; and securing a cover plate to the chassis floor such that the cover plate covers the battery modules. A vehicle chassis and a vehicle including such a chassis are also provided.

Description

Technical Field

[0001] This invention relates to a method for mounting a battery system to a frame of an electric vehicle, such as a passenger car. The invention also relates to a frame for an electric vehicle, and an electric vehicle comprising such a frame. Background Technology

[0002] A battery-electric vehicle is known in the prior art, comprising a chassis supporting the vehicle body. The chassis includes a frame structure having a pair of side rails connected by a plurality of rigid cross rails defining a plurality of bays. A battery pack, including a battery casing housing multiple energy storage devices, can be directly attached to the cross rails, at least a portion of which is located within the bays, and the cross rails extend in corresponding channels within the battery casing. The battery pack can be mounted in the frame and is replaceable when needed. However, a disadvantage of known electric vehicles is that the battery pack and the structure used to mount it to the vehicle constitute a significant portion of the vehicle's total weight.

[0003] One object of the present invention is to provide a method for mounting a battery system to a vehicle frame, and to provide a frame and a battery-electric vehicle including such a frame, wherein the disadvantage is at least partially overcome. Summary of the Invention

[0004] To this end, the present invention provides a method for mounting a battery system to the chassis floor of an electric vehicle, the battery system being adapted to provide power to drive the rolling motion of the electric vehicle, a plane extending through and parallel to the chassis floor, wherein a first side of the plane faces downward during use of the electric vehicle, the method comprising: securing battery modules of a plurality of battery modules to the chassis floor respectively on the first side of the plane, each battery module including electrical terminals; subsequently electrically connecting the electrical terminals of the battery modules to each other to form the battery system; and securing a cover plate to the chassis floor such that the cover plate covers the battery modules. The battery system is thus surrounded by the chassis floor and the cover plate during installation, eliminating the need for a separate housing for the entire battery system, thereby allowing for the construction of a lightweight battery system. In particular, no top plate for a battery housing is required between the chassis floor and the battery system.

[0005] According to this method, the battery modules are fixed to the chassis floor before they are electrically connected to form a battery system, and the battery system can be transported to the chassis and installed onto the chassis without the need for a housing.

[0006] The battery module can be placed close to or even directly in contact with the chassis floor. This results in a reduction in the height of the battery system compared to systems where a top cover exists between the battery system and the chassis floor. Due to this reduced height, any reinforcing structures used to protect the battery system can also be reduced in height, or even omitted altogether, further reducing the vehicle's weight.

[0007] In one example, securing each of the plurality of battery modules to the chassis floor includes moving the module toward a first side of the chassis floor in a direction substantially orthogonal to the first side, and then securing the module to the chassis floor.

[0008] In one example, the battery module or at least its battery cells are spaced at least 8 mm from the cover in the downward direction, for example, where the distance in the downward direction is between 8 mm and 25 mm. This prevents the formation of thermal bridges between the battery module (or its battery cells) and the cover, and reduces the impact of external weather conditions on the operation of the battery module. The space between the battery module and the cover may be filled with an insulating material, such as air or air-containing foam, and the cover is typically made of a metal or metal alloy such as aluminum.

[0009] In one example, the battery module is secured to the cover plate, for example by bolts and / or by adhesive.

[0010] In one example, when the cover is fixed to the chassis floor and parallel to the horizontal plane, and when the vehicle is stationary, the cover supports less than 50% of the total weight of the battery system. The remaining weight of the battery system is directly supported by the chassis floor.

[0011] In one example, the chassis floor has a floor lining on its interior-facing side. This floor lining typically includes carpet, padding, or soft materials such as rubber, felt, vinyl, and / or fabric. Typically, the portion of the floor lining closest to where vehicle occupants place their feet is covered with a floor mat. The distance between the battery module and the interior-facing side of the chassis floor can be, for example, less than 10 mm.

[0012] In one example, securing the battery modules to the chassis floor involves securing each battery module such that its electrical terminals face a direction opposite to the first side. This allows easy access to the electrical terminals before the cover is secured to the chassis floor.

[0013] In one example, each battery module includes multiple battery cells bonded together, and each individual battery cell includes a corresponding individual housing. The housing may, for example, be prismatic or cylindrical. Before the battery module is secured to the chassis floor, the housings of the battery cells may be exposed on the top and / or bottom sides of the battery module, so that the adhesive used to attach the battery cells to the chassis floor and / or the cover can be applied directly to the housing of each individual battery cell.

[0014] Alternatively, each battery module includes a single battery cell, each battery cell including a corresponding separate housing, and securing the battery module to the chassis floor includes securing each battery cell to the chassis floor independently.

[0015] In either case, securing the battery module to the chassis floor typically involves using an adhesive to attach the battery module to the chassis floor. Epoxy-based adhesives have been found to be particularly suitable. The adhesive allows the battery cells to be spaced less than 8 mm from the chassis floor. That is, the battery cells can directly contact the chassis floor on their non-terminal sides, for example, by extending a portion of the battery cell through the adhesive.

[0016] In one example, the electrical terminals of the battery cells are electrically connected to each other by ultrasonic welding or laser welding, for example, in this way, the battery terminals are electrically connected to each other via wires welded to the terminals. Batteries are susceptible to damage at high temperatures. Ultrasonic welding and laser welding allow conductive conduits to be attached to the terminals with relatively little heat generation.

[0017] In one example, each battery module comprises multiple battery cells enclosed by a housing. For instance, each battery module may include 24 to 48 or more battery cells internally electrically connected to each other, wherein the battery module has two or more electrical terminals. Typically, the terminals of individual battery cells are completely surrounded by the housing, and only the electrical terminals of the entire module are accessible from the outside of the housing. Multiple battery cells may be attached to each other using adhesives. The housing should support the battery cells within it, but is not necessarily required to withstand particularly strong forces. Examples of suitable materials for the housing include plastics. The housing may comprise or be made of a material with a lower density than the cover material.

[0018] In one example, the electrical terminals of the battery module are connected to each other by bolting the busbars to the terminals. Because bolted connections do not require high temperatures, heating of the terminals can be avoided.

[0019] In one example, the housings of one or more of the battery modules are bolted to the chassis floor. The chassis floor may have crossbeams on a first side for receiving the bolts.

[0020] In one example, when the battery module is attached to the chassis floor, the battery module is either in direct contact with the chassis floor or spaced apart from the chassis floor by no more than 8 mm, for example, no more than 5 mm, or for example, no more than 3 mm. This may result in a reduction in the height of the battery system, which would not be possible if there were a top cover between the chassis floor and the battery system.

[0021] In one example, the method further includes providing a reinforcing structure for the vehicle frame floor before securing the battery modules to the frame floor. The reinforcing structure may include beams and crossbeams that together define a spacer area for accommodating one or more battery modules. The reinforcing structure, such as its beams and crossbeams, may completely surround the sides of the multiple battery modules in this way, protecting the battery modules during a collision.

[0022] In one example, the chassis floor has a crossbeam on its first side.

[0023] In one example, when the vehicle is on a level surface, the lowest side of each battery module is positioned above the two distal edges of the reinforcing structure. If the vehicle travels over a bump or similar surface and the cover contacts the ground during this time, most of the impact is likely transmitted to the reinforcing structure rather than directly to the battery modules. The reinforcing structure may be positioned on a first side such that, during battery system installation and during vehicle use, no part of the battery system extends downward beyond the two distal edges of the reinforcing structure. Typically, the distal edges will be formed by longitudinal rails or beams extending along the longitudinal direction of the vehicle, wherein, when viewed in a top view, the battery system extends between the two longitudinal rails or beams.

[0024] In one example, the method includes securing the battery module to the cover. If the battery module has a housing surrounding multiple battery cells, this can be achieved, for example, by providing a beam support structure on the downward-facing side of the battery module and securing the housing to the cover using bolts extending through the beam support structure. Alternatively, particularly when the battery module is not surrounded by a common housing, the battery module can be secured to the cover using adhesive.

[0025] In one example, when viewed in a cross-section through a plane parallel to the downward direction, each line between the chassis floor and the cover plate, parallel to the downward direction, intersects at most one of the battery modules. This allows the battery modules to be positioned within 8 mm or less of the chassis floor by moving them parallel to the downward direction and toward the chassis floor by, for example, at least 10 cm, while remaining substantially unmoved in the direction parallel to the plane. Therefore, when the cover plate is removed from the chassis floor, the terminals of all battery modules in the battery system can be accessed, particularly without removing any battery module from the system to access another. Each battery module may have a height along the downward direction greater than half the distance between the chassis floor and the cover plate along the corresponding line intersecting the battery module.

[0026] According to a second aspect, the present invention provides a frame for an electric vehicle, the frame comprising: a frame floor, wherein a plane extends through and parallel to the frame floor, wherein a first side of the plane faces downward during use of the electric vehicle; a battery system comprising a plurality of battery modules having terminals electrically connected to each other, wherein the battery system is adapted to provide power to drive the rolling motion of the electric vehicle; and a cover plate fixed to the frame floor such that the cover plate covers the battery modules, wherein the battery modules are fixed to the frame floor on the first side of the plane, and wherein each battery module includes terminals facing the cover plate. The battery modules are fixed to the frame floor, thus eliminating the need for a top plate or similar structure for battery housings between the frame floor and the battery system, thereby reducing weight. After removing the cover plate, the downward-facing terminals can be easily accessed. Typically, each battery module is spaced apart from the cover plate.

[0027] In one example, when viewed in a cross-section through a plane parallel to the downward direction, each line between the chassis floor and the cover plate, parallel to the downward direction, intersects at most one of the battery modules. Therefore, when the cover plate is removed from the chassis floor, the terminals of all battery modules in the battery system can be accessed, particularly without removing any of the battery modules from the system to access another battery module.

[0028] In one example, each battery module includes multiple battery cells bonded together, each individual battery cell including a corresponding individual housing, or each battery module includes multiple battery cells surrounded by housings.

[0029] According to a third aspect, the present invention provides an electric vehicle including a frame according to a second aspect, the vehicle further comprising: at least four wheels arranged to contact the ground; one or more electric motors for driving rotation of the wheels; and a controller connected to the one or more electric motors and the battery system, adapted to control the amount of electricity supplied from the battery system to the one or more electric motors. Typically, the vehicle will be a passenger car with only four wheels in contact with the ground. Attached Figure Description

[0030] The invention will now be discussed in more detail with reference to the accompanying drawings, in which:

[0031] Figure 1 A schematic side view of an electric vehicle is shown, to which the battery system has been installed according to the method of the present invention;

[0032] Figure 2A An exploded perspective view of an embodiment of the present invention is shown, wherein a battery module having multiple battery cells is fixed to the vehicle frame floor.

[0033] Figure 2B and 2C They are shown respectively Figure 2A Top view of the battery module and through Figure 2B A cross-sectional view of the plane IIC-IIC;

[0034] Figure 3 Examples of a vehicle frame, battery module, and cover plate that can be used according to the present invention are shown;

[0035] Figure 4A and 4B An exploded perspective view of another embodiment of the invention is shown (in which each battery module is formed by individual battery cells bonded together and fixed to the vehicle's chassis floor) and a bottom view of the battery module are shown respectively.

[0036] Figure 5 A flowchart of the method of the present invention is shown. Detailed Implementation

[0037] Figure 1 An electric vehicle 1 according to the present invention is schematically shown. The vehicle is provided with an electric motor 3 for driving the rotation of wheels 2. A controller 4 is configured to control the amount of electricity supplied to the electric motor 3 from a battery system 120. The battery system 120 is attached to the underside of the vehicle to a frame floor 110 that generally faces downwards in the direction D during vehicle use. In the example shown, vehicle 1 is a passenger car with four wheels in contact with the ground.

[0038] Figure 2AAn exploded perspective view of a vehicle frame 100 according to a first embodiment of the present invention is shown. Although the frame 100 has an opening O on its underside in the exploded view, when the frame is assembled, the frame floor 110 substantially closes the opening O and provides support for mounting vehicle seats, etc., inside the vehicle. A plane P extends through and is substantially parallel to the frame floor 110. When assembled, the first side 111 of the plane P faces downward in the direction D. A floor upholstery 113 is provided on the side 112 of the frame floor 110 facing the opposite direction to the vehicle interior. The floor upholstery 113 is in the form of fabric or a soft material that can generally be directly contacted by vehicle occupants. When the frame floor 110 forms part of the frame 100, a plurality of battery modules 140 are fixed to the downward-facing side of the frame floor at the first side 111 of the plane P. The modules 140 are fixed to crossbeams 160 in a spaced-apart manner. The crossbeams are fixed to the frame floor and also increase the structural rigidity of the frame floor 110. On the lower side, the battery module 140 rests on a structure 170 in the form of an additional crossbeam, which is fixed to the bottom side plate 150 and further helps to increase the structural rigidity of the battery system 120. Once all battery modules 140 have been fixed to the chassis floor 110 and are electrically connected to each other, as shown in the reference... Figure 2B This forms the battery system 120. When the battery system 120 has been formed in this way, the cover plate 150 is fixed to the vehicle frame floor to cover the battery module, so that the module is vertically clamped between the crossbeam 160 and the structure 170, and the module is supported by the crossbeam 160 and supported on the structure 170.

[0039] Figure 2B The diagram shows a bottom view of the battery module 140 before it is secured to the reinforcing structure 170 and the cover plate 150 is secured to the chassis floor. Each battery module 140 includes multiple battery cells (only in...). Figure 2B (Seen in the cross-section of the leftmost module 140) and a housing 142 surrounding the battery cells. Each battery module 140 is individually mounted to two crossbeams 160 of the frame floor 110 via flanges 147 of its housing 142 using bolts 145. The crossbeams 160 are connected at their distal ends to longitudinal rails 162, which together form a frame. On the underside of each module, electrical terminals 143a, 143b are accessible from the underside of the frame floor, allowing busbars 148a, 148b to electrically connect the terminals of the different battery modules to each other, thus forming a battery system. Figure 2B In the middle, the battery system is not yet complete, because all the busbars except one have been connected to the terminals by bolts 146, while the uppermost busbar 148b on the right, shown in dashed line, has not yet been connected.

[0040] Figure 2C A cross-sectional view through plane IIC-IIC is shown, in which the battery module is fixed to both the crossbeam 160 and the reinforcing structure 170, and the cover plate 150 is fixed to the chassis floor 110. The upper side of the battery module abuts against the first downward side of the chassis floor 110 or is arranged within 1 cm of the first downward side of the chassis floor 110, and the floor lining 113 in the form of fabric or soft material is provided on the upper side of the opposite side. Figure 2C As shown, once the cover plate 150 has been installed onto the chassis floor 110, each battery module 140 is also supported on the support structure 170 and can be secured to the support structure 170, for example, using bolts (not shown), thereby clamping the module between the crossbeam 160 and the support structure 170. The structure 170 is typically secured to the cover plate 150 using bolts 159, which extend through the support structure 170 and into the flange 147 of the module housing 142, thus securing the module to the cover plate in this manner. However, the distal lower surface of each battery module 140 is spaced at a distance S between 5 and 10 cm from the upward-facing inner surface 151 of the cover plate 150. This allows the plate 150 to deform slightly without causing deformation of one or more battery modules when it encounters a protrusion, etc. Additionally, the busbars 148a, 148b can extend in the space between the lower surface of the battery module and the cover plate.

[0041] It should be noted that, according to the present invention, the chassis floor may be fixed to the vehicle frame before the battery system is installed, or the battery system may be formed and mounted on the chassis floor while the chassis floor is spaced apart from the vehicle frame, wherein once the battery system has been formed and fixed to the chassis floor, the chassis floor is mounted to the vehicle frame.

[0042] Figure 3 An exploded view of one embodiment of the invention is shown, wherein the chassis floor 310 is formed as an integral part of the vehicle chassis 300. The battery module 340, corresponding to the battery module 140, is directly attached to the first downward-facing side 311 of the chassis floor, after which a cover plate is also fixed to the chassis floor. Although not shown, a support structure corresponding to the support structure 170 may be provided, such that the module is sandwiched between the chassis floor and the support structure.

[0043] Figure 4A A perspective view of a vehicle frame 400 with a frame floor 410 is shown. The frame floor 410 has a crossbeam 460 on its underside, which defines a spacer area for receiving batteries therein. When a cover 450 is fixed to the frame floor, each spacer area is surrounded by a downward-facing first side 411 of the frame floor 410, the crossbeam 460, and the cover 450.

[0044] Figure 4B It shows Figure 4AA bottom view of the chassis floor 400, in which the battery system is formed by multiple individual prismatic battery cells as follows:

[0045] First, multiple battery cells are bonded together, for example, using epoxy glue, to form a battery module 430 that can be individually mounted to the chassis floor. Each battery cell 431 includes a separate housing 432, and each module can be formed as a separate housing without all its battery cells surrounding it and providing basic structural rigidity to the module. In the example shown, each module includes a total of 24 battery cells, consisting of 6 rows of 4 battery cells each. The electrical terminals of the battery cells are interconnected by conductive leads connected to the terminals. When the module is formed in this way, all terminals of the battery cells except for terminals 443a and 444b can be connected to another terminal via conductive leads. Next, the modules are placed in the spacer area and secured to the downward-facing first side 411 of the chassis floor using an adhesive 459, such as epoxy glue, through their upper sides.

[0046] Next, once all modules are secured to the chassis floor in this manner, conductive leads are connected between terminals 443a and 444b of the different modules to form the battery system. Therefore, the battery system is only complete after the modules have been secured to the chassis floor. The conductive leads between the terminals of the different modules are interconnected by laser welding or ultrasonic welding to prevent battery damage due to overheating, for example, by using spot welding instead of conventional welding. Figure 4B In this battery system, all modules are electrically connected to each other to form a battery system with external power leads 439a and 439b.

[0047] Figure 5 A flowchart of a method 500 according to the present invention is shown. The method includes independently securing 510 of a plurality of battery modules to a vehicle frame floor at a first side of the plane. Next, the electrical terminals of the battery modules are connected to each other 520 to form a battery system. Once the battery system is formed in this manner, a cover is secured 530 to the vehicle frame floor such that the cover covers the battery modules.

[0048] The invention has been described above with reference to several exemplary embodiments shown in the accompanying drawings. Modifications and alternative implementations of some components or elements are possible and are included within the scope of protection defined in the appended claims.

Claims

1. A method (500) for mounting a battery system to a frame floor (110; 310; 410) of an electric vehicle (1), the battery system being adapted to provide power to drive the rolling motion of the electric vehicle, a plane (P) extending through and parallel to the frame floor, a first side (111) of the plane (P) during use of the electric vehicle. 311； 411) Facing downwards (D), the method includes: Battery modules (140; 340; 440) of a plurality of battery modules are respectively fixed (510) to the vehicle frame floor on the first side of the plane, and each battery module includes electrical terminals (133a, 133b; 443a, 443b). The electrical terminals of the battery modules are then electrically connected to each other (520) to form the battery system (120); and The cover plate (150; 350; 450) is then fixed (530) to the chassis floor so that the cover plate covers the battery module.

2. The method according to claim 1, wherein the battery module is spaced at least 8 mm (S) from the cover plate (150) in the downward direction.

3. The method according to claim 1 or 2, wherein the chassis floor (110) has a floor trim (113) on its side (112) facing the vehicle interior.

4. The method according to claim 1 or 2, wherein securing the battery module to the vehicle frame floor (110; 310; 410) comprises securing each battery module such that the electrical terminals of the battery module face a direction opposite to the first side (111; 311; 411).

5. The method according to claim 1 or 2, wherein each battery module comprises a plurality of battery cells (441) bonded together, and each individual battery cell comprises a corresponding individual housing (132).

6. The method of claim 5, wherein securing the battery module to the chassis floor comprises securing the battery module to the chassis floor using an adhesive (459).

7. The method according to claim 5, wherein the electrical connection of the electrical terminals (433a, 433b) of the module to each other is performed by ultrasonic welding or laser welding.

8. The method according to claim 1 or 2, wherein each battery module (140; 340) comprises a plurality of battery cells (141) surrounded by a housing (142).

9. The method of claim 8, comprising securing the housing of one or more of the battery modules (140; 340) to the vehicle frame floor using bolts (145).

10. The method according to claim 1 or 2, further comprising securing the battery module (140; 340; 440) to the cover plate (150; 350; 450).

11. The method according to claim 8, wherein the electrical connection of the electrical terminals of the battery module to each other is performed by bolting the busbars (145a, 145b) to the terminals (433a, 433b).

12. The method according to claim 1 or 2, wherein, When fixed to the chassis floor, the battery module (140; 340; 440) is in direct contact with the chassis floor (110) or spaced apart from the chassis floor by no more than 8 mm.

13. A frame (100; 300; 400) for an electric vehicle (1), comprising: Frame floor (110; 310; 410), a plane (P) extends through and parallel to the chassis floor, and during use of the electric vehicle, a first side (111; 311; 411) of the plane faces downward (D). A battery system (120) comprising a plurality of battery modules (140; 340; 440) having terminals electrically connected to each other, the battery system being adapted to provide power to drive the rolling motion of the electric vehicle; A cover plate (150; 350; 450) is fixed to the chassis floor such that the cover plate covers the battery module; The battery modules are fixed to the vehicle frame floor on the first side (111; 311; 411) of the plane (P), and each battery module includes electrical terminals (133a, 133b; 143a, 143b) facing the cover.

14. The frame according to claim 13, wherein each battery module includes a plurality of battery cells (131) bonded together, each individual battery cell (131) including a corresponding individual housing (132), or each battery module (140) includes a plurality of battery cells (141) surrounded by housings (142).

15. An electric vehicle (1) including the frame (100) according to claim 13 or 14, further comprising: Arranged for contact with the ground at least four wheels (2); One or more electric motors (3) for driving the rotation of the wheels; and A controller (4) is connected to one or more motors and the battery system and is adapted to control the amount of electricity supplied from the battery system to the one or more motors.

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