BATTERY PACK INCLUDING CUP-SHAPED UPPER AND LOWER COVERS AND A Z-PROFILE, MOTOR VEHICLE AND PROCESS BASED ON SUCH A BATTERY PACK

Abstract

The invention relates to a battery pack for a motor vehicle, comprising: - an upper cover (CS) having a downward projection and a first outer edge (SD), - a lower cover (CI) having an upward projection and a second outer edge (ID), - battery modules (M) arranged between the covers (CS, CI); - at least one internal cross member (TI) attached to the upper cover (CS); - at least one side profile (PL) comprising an internal portion (LP) disposed above the upper portion and / or the first inner edge (SP), and attached thereto; and an external portion (LD) disposed above the first and second outer edges (ID, SD), and attached thereto. The invention also relates to a vehicle and a method based on such a battery pack. Abstract figure: Fig. 3

Description

Title of the invention: BATTERY PACK COMPRISING DISH-SHAPED TOP AND LOWER COVERS AND A Z-SHAPED PROFILE, MOTOR VEHICLE AND METHOD BASED ON SUCH A BATTERY PACK

[0001] The invention relates to the field of high-voltage electrical energy storage systems in motor vehicles, and more particularly the protection of motor vehicle battery packs against impacts on said vehicle.

[0002] Applicant's battery packs generally consist of the following elements, illustrated in [Fig.l], from bottom to top: - a reinforced lower CI cover to resist vertical upward impacts (or so-called “stone” impacts); - a cooling system comprising a PR cooling plate in the lower part; - a Cl structural frame to resist frontal and lateral impacts on the vehicle: including an external C2 frame made of PL aluminum profiles and TL side cross members; - M battery modules fixed to the lateral cross members TL of the CS structural frame; - a bus bar (or “Busbar” in English), not shown; and - a top cover not shown.

[0003] The cooling plate PR is directly in contact with the M modules to promote heat exchange by conductivity. However, it is in the lower part of the M modules, while the heated air around the M modules tends to rise upwards, which implies a non-optimal cooling efficiency.

[0004] The height requirement is significant, because there are two empty space zones in the upper and lower parts compared to the M modules: the upper space is allocated to any gas produced in the event of thermal runaway, and the lower space is allocated to protection against vertical upward impacts (known as "stone impacts").

[0005] The lateral cross members TL forming part of the structural frame C1, have a side post impact resistance function. They are in the lower part of the battery pack, and they are limited in height in order to leave space for the bus bars in the upper part. The cross members TL are therefore not opposite a body side member where they enter during lateral impact forces. This results in a non-optimal force output, a need to reinforce these cross members TL and to couple these forces with the forces of a body base cross member.

[0006] The lateral profile PL being part of the structural frame Cl, its function is to distribute the forces on each crosspiece and to protect the modules M from intrusions in the event of a side post impact. This aluminum PL profile is bulky.

[0007] An objective of the present invention is to remedy the defects of the prior art, and in particular to limit the space taken up around the battery pack while having good mechanical strength, good shock resistance, and optimized cooling efficiency.

[0008] To achieve this objective, the invention proposes a motor vehicle in a spatial reference frame comprising a lateral axis along a lateral direction of the motor vehicle, defining an internal direction towards the inside of the motor vehicle, and an external direction towards the outside of the motor vehicle, and a vertical axis perpendicular to the lateral axis, the motor vehicle comprising a battery pack which comprises: - a hollow upper cover open downwards with reference to the vertical axis, comprising an upper part extended laterally by a first internal edge forming a downward projection with reference to the vertical axis, extended laterally by a first external edge forming an external lateral projection with reference to the lateral axis, - a hollow lower cover open upwards with reference to the vertical axis, comprising a second internal edge forming an upward projection with reference to the vertical axis, extended laterally by a second external edge forming an external lateral projection with reference to the lateral axis, the first external edge being arranged above the second external edge, - battery modules arranged between the top cover and the bottom cover; - at least one internal crosspiece passing between battery modules, said crosspiece being secured to the upper cover; - at least one lateral profile comprising an internal portion arranged above the upper part and / or the first internal edge, being secured thereto; and an external portion arranged above the first and second external edges, being secured thereto.

[0009] Advantageously, the invention makes it possible to have an arrangement of the internal elements optimized to meet the requirements of cooling, management of thermal runaway, optimization of the chemical volume (Z and Y space), management of lateral shock and vertical shock upwards (called "pebble"), compared to a standard pack. The invention consequently involves a gain in volume and performance, as well as a reduction in mass.

[0010] According to a variant, the external portion and the first and second external edges are configured to be secured to a side member of the motor vehicle body.

[0011] This allows for a mounting part that withstands impacts on the vehicle so as to protect the battery modules.

[0012] According to a variant, the external portion and the first and second external edges are configured to be secured to said spar by screwing from below with reference to the vertical axis.

[0013] This allows the battery pack to be easily attached to the motor vehicle.

[0014] According to a variant, said crosspiece is welded to the upper cover.

[0015] This allows for good cohesion of the internal reinforcement parts of the battery pack and internal reinforcement of the upper cover.

[0016] According to one variant, the upper cover is welded to the side profile.

[0017] This allows for good cohesion of the battery pack and external reinforcement secured to the upper cover.

[0018] According to one variant, the side profile comprises steel.

[0019] This allows for good mechanical strength of this flat reinforcement part.

[0020] According to a variant, said internal cross member is configured to extend laterally along the lateral axis perpendicular to said spar.

[0021] This allows the impacts of the side member to be made on the internal cross member.

[0022] According to one variant, the battery pack comprises an immersive fluid cooling system.

[0023] This allows for efficient cooling by means of a cooling fluid in the battery pack.

[0024] According to one variant, the motor vehicle further comprises a body side member, and the battery pack is fixed to the body side member.

[0025] Another object of the invention relates to a method of mounting a battery pack of a motor vehicle according to the invention, comprising the following steps: - a step of placing the battery pack so that the external portion and the first and second external edges are arranged below the body side member; and - a securing step to screw the external portion and the first and second external edges to the body side member, by screwing from below.

[0026] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates an exploded view in space of a first type of motor vehicle battery pack arrangement according to the prior art; - [Fig.2] schematically illustrates a sectional view of a second type of battery pack arrangement according to the prior art, fixed in a vehicle body automobile; - [Fig.3] schematically illustrates a sectional view of a battery pack arrangement according to a first embodiment of the invention, fixed in a motor vehicle body; - [Fig.4] schematically illustrates a sectional view of a battery pack arrangement according to a second embodiment, fixed in a motor vehicle body; and - [Fig.5] schematically illustrates a sectional view of a battery pack arrangement according to a third embodiment, fixed in a motor vehicle body.

[0027] The invention relates to a novel arrangement of a motor vehicle battery pack. The invention is described in a spatial reference frame comprising a lateral axis Y along a lateral direction of the battery pack, and a vertical axis Z perpendicular to the lateral axis Y.

[0028] In this new arrangement, the battery pack includes: - an upper cover CS of modified shape compared to those of the prior art; - a thin lateral PL profile, preferably made of steel, replacing the thick aluminum profile of the prior art; - raised TI internal crossmembers along the Z axis, aligned and assembled with the new PL profile via the CS upper cover; the height of the TI internal crossmember can be optimized to allow 100% overlap with the LV body side member profile. A bracket E can be added to the lower part of the TI internal crossmember as illustrated in [Fig.5], to allow support in the area of ​​the rebates (edges ID, SD detailed below) of the CS upper and CI lower covers, in order to limit intrusion in this area. - an immersive cooling system that replaces the prior art cooling plate; - a lower cover CI of modified shape compared to those of the prior art.

[0029] The invention makes it possible to have a gain in volume along the Y and Z axes; and a gain in mass and performance.

[0030] The arrangements of Figures 2 and 3 show the evolution of the invention. The lateral transverse TL fixed to the cover in the prior art has been replaced by the upper cover CS in the form of an inverted bowl with an upper part at the bottom of the bowl, a first lateral internal edge SP and a first external edge SD at a lateral end. In particular, the upper part is extended laterally by the first internal edge SP which forms a downward projection with reference to the vertical axis Z. The first internal edge SP is extended laterally by the first external edge SD which forms a lateral projection with reference to the lateral axis Y,

[0031] The lower cover CI also has a bowl shape with optionally a lower part at the bottom of the bowl, a second lateral internal edge IP and a second external edge ID at a lateral end. In particular, the second internal edge IP forms an upward projection with reference to the vertical axis Z, and is extended laterally by the second external edge ID forming a lateral projection with reference to the lateral axis Y.

[0032] In the context of the invention, the first external edge SD is arranged above the second external edge ID. They can be against each other or spaced apart depending on the variant considered. The same applies to the parts of the upper cover CS and the side profile PL. They are spaced apart at the external part in [Fig.5].

[0033] Furthermore, the outer edges SD, ID are secured together and to the side profile PL, and are configured to be secured to a body side member LV. A fixing part F1 is provided for this purpose, for example a fixing screw.

[0034] In the arrangements of Figures 2 and 3, the differences are as follows: - the CS top cover replaces the external vertical wall of the TL profile; - the lower cover CI replaces the intermediate vertical wall of the TL profile; - the remaining part of the TL profile is removed; - the bending resistance shock function (called "post shock") is ensured by the addition of the PL side profile in low-profile steel, on the outside of the CS top cover; - the internal cross members TI are raised along the Z axis so as to be opposite the LV side member and welded to the upper cover CS and the lateral profile PL. In this way, a new structural frame is reconstituted between the side members and the lateral profile PL in steel in the shape of a Z or L bracket.

[0035] In addition to the gain in mass and performance associated with the optimization of thermal and shock management, there is a gain in space along the Y axis due to the reduction in the size of the PL profile. This new PL profile, preferably made of steel, more preferably with a very high elastic limit (of the order of 1000 - 1500 MPa), has an L or Z shape, the upper edge being able to increase the bending stiffness to counter intrusions.

[0036] Some principle calculations were carried out in order to demonstrate the potential of the concept. The fixing part F1 is bent due to the shocks, but the battery modules M are not significantly affected.

[0037] For reasons of modeling simplicity, in [Fig.5], the vertical wall of the upper cover CS and the angle-shaped profile PL are merged, while keeping representative thickness and material properties.

[0038] The upper cover CS can be obtained by several different shaping processes, for example by stamping or by folding.

[0039] In the case of stamping, the advantage is that a single, watertight part is obtained. The disadvantage is that the size of the stamping tool is relatively large and the cup shape requires stamping slopes of around 6 degrees ([Fig.4]), which is unfavorable for the transmission of shock forces.

[0040] In the case of folding, the advantage is that the tooling is more accessible than for stamping, and it is possible to have a practically vertical wall inclination ( [Fig.5]), favorable to the passage of impact force. The disadvantage is that the four corners of the cover are obtained by welding between folded edges, the seal is then not ensured. This requires the addition of four plastic inserts with swelling product or another solution.

[0041] The proposed battery pack can be obtained according to several different mounting methods, preferably with fixing of the external portion LD and of the first and second external edges ID, SD to the spar LV, from below as illustrated in Figures 3 to 5.

[0042] The assembly can be carried out by an assembly method equivalent to the standard pack, with installation of the M modules from above (upper cover CS turned over), to which is added a 180° rotation of the upper cover CS and the M modules around the longitudinal axis of the vehicle.

[0043] The assembly can also be done by an assembly process with installation of the M modules from below, by robots and screwed onto the structural frame, directly in the vehicle position.

[0044] Cooling can be done by a cooling plate as in the prior art or by an immersive fluid cooling system.

[0045] The body floor can be standard, or it can be removed. In this case, it is a part of the upper cover CS of the battery pack which provides at least a partial floor function (sealing of the body, support for the occupants, etc.).

Claims

Claims

1. Motor vehicle in a spatial reference frame comprising a lateral axis (Y) along a lateral direction of the motor vehicle, defining an internal direction towards the inside of the motor vehicle, and an external direction towards the outside of the motor vehicle, and a vertical axis (Z) perpendicular to the lateral axis (Y), the motor vehicle comprising a battery pack which comprises: - a hollow upper cover (CS) open downwards with reference to the vertical axis (Z), comprising an upper part extended laterally by a first internal edge (SP) forming a downward projection with reference to the vertical axis (Z), extended laterally by a first external edge (SD) forming an external lateral projection with reference to the lateral axis (Y), - a hollow lower cover (CI) open upwards with reference to the vertical axis (Z), comprising a second internal edge (IP) forming an upward projection with reference to the vertical axis (Z),extended laterally by a second external edge (ID) forming an external lateral projection with reference to the lateral axis (Y), the first external edge (SD) being arranged above the second external edge (ID), - battery modules (M) arranged between the upper cover (CS) and the lower cover (CI); - at least one internal crosspiece (TI) passing between battery modules, said crosspiece (TI) being secured to the upper cover (CS); - at least one lateral profile (PL) comprising an internal portion (LP) arranged above the upper part and / or the first internal edge (SP), being secured thereto; and an external portion (LD) arranged above the first and second external edges (ID, SD), being secured thereto.,

2. Motor vehicle according to claim 1, characterized in that the external portion (LD) and the first and second external edges (ID, SD) are configured to be secured to a side member (LV) of the body of the motor vehicle.

3. Motor vehicle according to any one of claims 1 to 2, characterized in that the external portion (LD) and the first and second external edges (ID, SD), are configured to be secured to said side member (LV) by screwing from below with reference to the vertical axis (Z).

4. Motor vehicle according to any one of claims 1 to 3, characterized in that said crossmember (TI) is welded to the upper cover (CS).

5. Motor vehicle according to any one of claims 1 to 4, characterized in that the upper cover (CS) is welded to the side profile (PL).

6. Motor vehicle according to any one of claims 1 to 5, characterized in that the lateral profile (PL) comprises steel.

7. Motor vehicle according to any one of claims 1 to 6, characterized in that said internal cross member (TI) is configured to extend laterally along the lateral axis (Y) perpendicular to said side member (LV).

8. Motor vehicle according to any one of claims 1 to 7, characterized in that it comprises an immersible fluid cooling system.

9. Motor vehicle according to any one of claims 1 to 8, further comprising a body side member (LV), characterized in that the battery pack is fixed to the body side member (LV).

10. Method for mounting a battery pack of a motor vehicle according to claim 9, comprising the following steps: - a step of positioning the battery pack so that the external portion (LD) and the first and second external edges (ID, SD) are arranged below the body side member (LV); and - a securing step for screwing the external portion (LD) and the first and second external edges (ID, SD) to the body side member (LV) by screwing from below.

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