Battery system for motor vehicles including means for positioning battery cells

Abstract

The battery system (2) for a motor vehicle (1) comprises: - a battery case (3) including a support plate (24) and a cover together delimiting an internal space of the battery system (2), - a stack including several battery cells (4) arranged in the battery case (3) on the support plate (24) and aligned along a main longitudinal axis of the battery system (2), - positioning means intended to limit a displacement of at least one of the battery cells (4) along a vertical axis orthogonal to the main longitudinal axis of the battery system (2).The positioning means include at least one first positioning ring (10) forming a stop for at least part of an upper face of the first battery cell (4), the first positioning ring (10) being cantilevered on the battery case (3) with clearance along the vertical axis within a predetermined tolerance range. Figure 4.

Description

Title of the invention: Battery system for motor vehicles comprising means for positioning battery cells. Technical field of the invention

[0001] The invention relates to a battery system for a motor vehicle, including in particular means for positioning the battery cells. Technical background

[0002] Battery systems for motor vehicles, generally comprising a housing in which one or more battery modules are arranged, are already known in the art. Each battery module comprises a stack of several battery cells. To facilitate assembly and limit the swelling of the battery cells, it is known to use cell retention means configured to hold the battery cells of a battery module tightly against each other and to limit longitudinal or lateral displacement of the battery cells.

[0003] Furthermore, a battery system comprising positioning bars extending above the battery cells along the entire length of the battery module is known from document JP2023117939A. These bars are designed to limit vertical displacement or swelling of the battery cells. Such a battery system has the drawback of not taking into account assembly tolerances, particularly the possible lack of flatness in the longitudinal stacking of battery cells. Consequently, in the event of unevenness in the battery cells, there is a risk that the positioning bars will not be in contact with one or more of the battery cells and will therefore not fulfill their function of limiting displacement and swelling of these battery cells.

[0004] Document EP4145608A1 describes a battery system comprising a positioning plate arranged above the battery cells to limit their vertical displacement. The positioning plate includes lines of mechanical weakness that allow it to deform and thus tolerate a certain degree of displacement of the battery cells located beneath the plate. However, such a battery system has several drawbacks. First, the positioning plate limiting the vertical displacement of the battery cells is bulky. Furthermore, it is not possible to create a large number of points of mechanical weakness without excessively weakening the positioning plate. Consequently, the plate cannot precisely compensate for assembly defects in each individual battery cell. Summary of the invention

[0005] The invention aims in particular to provide a battery system comprising battery cells and means for positioning the battery cells allowing to limit a vertical displacement of the battery cells and taking into account the assembly tolerances.

[0006] To this end, the invention relates to a battery system for a motor vehicle, comprising: - a battery casing comprising a support plate and a cover which together define an internal space for the battery system, - a stack comprising several battery cells arranged in the battery case on the support plate and aligned along a main longitudinal axis of the battery system, - positioning means intended to limit a displacement of at least one of the first battery cells along a vertical axis, orthogonal to the main longitudinal axis of the battery system, characterized in that the positioning means comprise at least one first positioning ring forming a stop for at least part of an upper face of the first battery cell, the first positioning ring being mounted cantilevered on the battery case with a clearance along the vertical axis within a predetermined tolerance range.

[0007] The cantilevered mounting of the first positioning ring on the battery housing with a play along the vertical axis within a predetermined tolerance range makes it possible to limit a vertical displacement of the first battery cell while taking into account possible mounting tolerances.

[0008] It is understood that limiting the vertical displacement of the first battery cell by the first positioning ring corresponds to limiting the displacement of the entire battery cell or only a portion of the battery cell, particularly in the case of swelling of the first battery cell. Limiting swelling of the first battery cell improves its lifespan.

[0009] The expression "at least one first positioning ring forming a stop for at least one upper face of the first battery cell" means that the first positioning ring forms a direct or indirect stop for at least a portion of the upper face of the first battery cell. "Indirect stop" means that one or more intervening elements may be interposed between the first positioning ring and the upper face of the first battery cell. "Direct stop" means This designates the fact that the first positioning ring forms a stop for at least part of the upper face of the first battery cell by being in direct contact with that part of the upper face of the first battery cell. It is understood that the expression "first battery cell" does not necessarily refer to the first battery cell in the stack according to the stacking direction of the battery cells, but refers to any battery cell within the stack of battery cells.

[0010] It is understood that the predetermined tolerance range varies according to the embodiment, particularly depending on the dimensions of the battery system and the various elements included therein. In particular, it can be foreseen that the predetermined tolerance range varies according to the dimensions of the battery cells. Depending on the embodiment, it can, for example, be foreseen that the predetermined tolerance range is 1 to 6 mm, preferably 2 to 5 mm, and even more preferably 3 to 4 mm.

[0011] The invention may also include one or more of the following features the following optional ones, taken alone or in combination.

[0012] Advantageously, the first positioning ring forms a stop for at least part of an upper face of a second battery cell, the second battery cell being adjacent to the first battery cell. It is thus understood that a first positioning ring can form a stop for two battery cells, reducing the number of first positioning rings required, and therefore reducing the mass of the battery system and its manufacturing cost.

[0013] Advantageously, the first positioning ring acts as a stop for a first lateral edge of the upper face of the first battery cell. The positioning means further comprise at least one second positioning ring acting as a stop for a second lateral edge of the upper face of the first battery cell, opposite and facing the first positioning ring. Limiting the vertical displacement of the first battery cell by means of the first and second positioning rings arranged respectively at its first and second lateral edges allows for better control of the vertical positioning of the first battery cell.

[0014] According to one embodiment, the battery system further comprises an interlayer element arranged between, on the one hand, the first positioning ring and / or the second positioning ring, and, on the other hand, at least a portion of the upper face of the first battery cell. Such an interlayer element may have various functions, such as a function of protecting the battery cells. or a function of positioning the battery cells relative to each other or a support function for another component of the battery system. It is understood that, due to the presence of an intervening element between the first positioning ring and / or the second positioning ring and at least part of the upper face of the first battery cell, the first positioning ring and / or the second positioning ring form(s) an indirect stop for at least part of the upper face of the first battery cell.

[0015] Preferably, a positioning relief extends projecting from an inner face of a side wall of the battery housing and forms a support for at least one first positioning ring. The positioning relief has a stepped shape comprising an upper step and a lower step. A portion of the lower face of the first positioning ring rests on the upper step of the positioning relief. The height difference between the upper and lower steps is configured to allow the first positioning ring to be cantilevered, with the clearance around the vertical axis within a predetermined tolerance range. Such a positioning relief provides a simple and economical way to cantilever the first positioning ring.It is understood that it is possible to adjust, among other things, the height difference between the upper and lower steps so that the play along the vertical axis of the first positioning ring is within the predetermined tolerance range.

[0016] Preferably, the positioning relief extends axially along the inner face of the side wall of the housing from a first longitudinal end to a second longitudinal end of the battery housing so as to form a support for several first positioning rings. Such a positioning relief makes it possible to achieve a simple and economical cantilevered mounting of several first positioning rings.

[0017] Advantageously, at least one of the first positioning rings and / or at least one of the second positioning rings comprises a central through hole, the positioning means further comprising means for attaching the first positioning ring and / or the second positioning ring to the battery housing, including a positioning screw extending through the central through hole of the first positioning ring and / or the second positioning ring and being screwed into a corresponding tapped hole in the battery housing. This is a simple and economical means of attaching the first positioning ring and / or the second positioning ring. to the battery case. This method of attachment also allows the first positioning ring to be mounted in cantilever mode with play along the vertical axis.

[0018] Advantageously, at least a portion of an external thread of the positioning screw is coated with threadlocker. The use of threadlocker reduces the risk of the positioning screw loosening, for example due to vibrations, even with a low tightening torque of the positioning screw.

[0019] Preferably, the positioning screw is screwed in with a tightening torque of between 2 and 8 Nm, preferably between 2 and 5 Nm, preferably again between 2 and 3 Nm. Such a tightening torque is high enough to reduce the risk of loosening the positioning screw, for example due to vibrations, and low enough to prevent the first positioning ring or the second positioning ring from applying pressure on the first battery cell and, possibly, the second battery cell, which is greater than a mechanical resistance threshold of the first or second battery cell.

[0020] Advantageously, the battery housing comprises at least one positioning member extending vertically from the support plate. The positioning member has a free end in which a tapped hole is provided. A second positioning ring is attached to the free end of the positioning member by screwing a positioning screw, passing through the central orifice of the second positioning ring, into the tapped hole of the positioning member. The positioning member extending from the support plate thus allows the second positioning ring to be screwed in and ensures correct positioning of the second positioning ring relative to the battery cell, for which it acts as a stop.Preferably, the positioning member forms a positioning rod extending vertically from the support plate, a tapped hole being provided in the free end of the positioning rod, a second positioning ring being fixed to the free end of the positioning rod by screwing a positioning screw, passing through the central orifice of the second positioning ring, into the tapped hole of the positioning rod.

[0021] Preferably, the first positioning ring and / or the second positioning ring has a shape with rotational symmetry about its principal axis. Such a shape facilitates the assembly of the battery system since the orientation of the positioning ring with respect to its axis of symmetry is irrelevant when installing the first and / or the second positioning ring. Brief description of the figures

[0022] The invention will be better understood upon reading the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0023] Fig. 1 is a view of a motor vehicle comprising a motor vehicle battery system according to an embodiment of the invention.

[0024] Fig. 2 is a perspective view of the battery system of Fig. 1 in which the battery system cover is not shown.

[0025] Fig. 3 is a close-up perspective view of part of the battery system of Fig. 2.

[0026] Fig. 4 is a cross-sectional view of part of the battery system of Fig. 2.

[0027] Fig. 5 is an exploded view of the positioning means.

[0028] Fig. 6 is a cross-sectional view of part of the battery system. Detailed description

[0029] Figure 1 shows a motor vehicle 1 comprising a battery system 2 according to the invention. In this case, the battery system 2 is intended to supply electrical energy to the motor vehicle 1, for example, for the propulsion of the motor vehicle 1. The invention applies to any type of motor vehicle 1, in particular "heavy goods vehicles" such as buses and road transport vehicles (trucks, tractors, trailers).

[0030] Figures 2 to 6 show the battery system 2 according to the present embodiment. The battery system 2 includes, in particular, a battery housing 3 comprising a support plate 24 and a cover (not shown) together defining an internal space of the battery system 2.

[0031] The battery system 2 comprises a stack of several battery cells 4 arranged in the battery housing 3 on the support plate 24 and aligned along a principal longitudinal axis A of the battery system 2. According to the present embodiment, the battery cells 4 are divided into two subsets 5 of battery cells 4, also called battery modules or "strings," each subset 5 of battery cells 4 being divided into three blocks 6 of battery cells 4, each block 6 of battery cells 4 comprising a stack of several battery cells 4 aligned along the principal longitudinal axis A of the battery system 2. Of course, the arrangement of the battery cells in subsets 5 and blocks 6 may vary according to the embodiment.Each battery cell 4 comprises an upper face having a first lateral edge 7 arranged opposite a lateral wall 8 of the battery case 3 and a second lateral edge 9, . opposite to the first lateral edge 7 and extending, in this case, into a median portion of the battery housing 3.

[0032] The battery system 2 includes positioning means for limiting the displacement of at least one of the battery cells 4 along a vertical axis orthogonal to the main longitudinal axis 6 of the battery system 2. According to this embodiment, the positioning means include first positioning rings 10, each first positioning ring 10 forming a stop for the first lateral edge 7 of the upper face of at least one of the battery cells 4. The positioning means further include second positioning rings 11 forming a stop for the second lateral edge 9 of the upper face of at least one of the battery cells 4, opposite and facing the first positioning rings 10. According to this embodiment, the positioning means include eighteen first positioning rings 10 and nine second positioning rings 11.

[0033] As illustrated in [Fig. 2], each first positioning ring 10 forms a stop for the first lateral edge 7 of the upper face of two adjacent battery cells within the same block 6 of battery cells 4. Each second positioning ring 11 forms a stop for the second lateral edge 9 of the upper face of four battery cells 4 distributed into two adjacent battery cells 4 within the same block 6 of battery cells 4 of a first subset 5 of battery cells 4 and two adjacent battery cells 4 within the same block 6 of battery cells 4 of a second subset 5 of battery cells 4 (Figures 2 and 3). Thus, it is understood that four first positioning rings 10 and two second positioning rings 11 are sufficient to form a stop for the two respective lateral edges 7, 9 of the upper faces of four battery cells 4.According to other embodiments, the number of first positioning rings 10 and / or the number of second positioning rings 11 may vary. For example, the battery system 2 may include as many first positioning rings 10 and / or as many second positioning rings 11 as there are battery cells 4.

[0034] According to this embodiment, the first positioning rings 10 are all identical to each other and the second positioning rings 11 are all identical to each other. According to other embodiments, it may be provided that at least one of the first positioning rings 10 has a different shape from that of the other first positioning rings 10 and / or that at least one of the second positioning rings 11 has a different shape from that of the other second positioning rings 11. According to this embodiment, the first positioning rings 10 are identical to the second positioning rings 11. Positioning. More specifically, as illustrated in [Fig. 5], each first positioning ring 10 and each second positioning ring 11 has a shape with rotational symmetry about its principal axis 12. Each first positioning ring 10 and each second positioning ring 11 includes a central through-hole 13 and reinforcing ribs 25 extending from the central through-hole 13 to a peripheral edge of the first positioning ring 10 or the second positioning ring 11. The reinforcing ribs 25, six in number in this case, are regularly distributed around the central through-hole 13.The reinforcing ribs 25 are particularly useful when the first or second positioning ring 10, 11 is made of plastic so as to reduce the risk of deformation of the first or second positioning ring 10, 11 which could impair its positioning function.

[0035] The positioning means further include means for attaching the first positioning rings 10 and the second positioning rings 11 to the battery housing 3. The attachment means include positioning screws 14, each positioning screw 14 extending through the central through hole 13 of one of the first or second positioning rings 11 and being screwed into a corresponding tapped hole 15 in the battery housing 3. According to the present embodiment, for the first positioning rings 10, the tapped hole 15 is provided in a positioning relief 16, and for the second positioning rings 11, the tapped hole 15 is provided in a positioning member 17, which, according to the present embodiment, is formed by a positioning rod.

[0036] Each positioning screw 14 has an external thread 22 that complements the tapped hole 15 into which it is screwed. In embodiments, each positioning screw 14 is screwed into a tapped hole 15 with a tightening torque of between 2 and 8 Nm, preferably between 2 and 5 Nm, and even more preferably between 2 and 3 Nm. Such a tightening torque is sufficiently high to reduce the risk of the positioning screw 14 loosening, for example, due to vibrations, and sufficiently low to prevent the first positioning ring 10 and / or the second positioning ring 11 from applying pressure to the battery cell 4 that exceeds a mechanical resistance threshold of the battery cell 4. In the present embodiment, at least a portion of the external thread 22 of each positioning screw 14 is coated with threadlocker.The use of threadlocker reduces the risk of loosening the positioning screw 14, for example due to vibrations, even with tightening torque. weak positioning screw 14, for example with a tightening torque between 2 and 3 Nm

[0037] As illustrated in Figures 4, 5 and 6, a washer 23 is arranged between the head of each positioning screw 14 and the first or second positioning ring 10, 11 to which it is associated. Such a washer 23 is particularly useful when the first positioning ring 10 or the second positioning ring 11 is made of plastic so as to reduce the risk of damaging the first positioning ring 10 or the second positioning ring 11 when tightening the positioning screw 14.

[0038] According to the present embodiment, the battery system 2 comprises two positioning ridges 16 (only one of the two positioning ridges 16 being visible in the figures). Each positioning ridge 16 projects from an inner face of one of the two side walls 8 of the battery housing 3. Each positioning ridge 16 forms a support for several first positioning rings 10. More specifically, in the present case, each positioning ridge 16 extends axially along the inner face of one of the two side walls 8 of the battery housing 3 from a first longitudinal end to a second longitudinal end of the battery housing 3 so as to form a support for several first positioning rings 10. In particular, in the present case, each positioning ridge 16 forms a support for nine first positioning rings 10.Consequently, nine tapped holes 15 are provided in each positioning relief 16. According to this embodiment, each positioning relief 16 has a stepped shape comprising an upper step 18 and a lower step 19 (Figures 3, 4, and 6). The positioning relief 16 is, for example, formed by machining the side wall 8 of the battery housing 3. It is also possible for the positioning relief 16 to be formed by any other known means, for example, by bonding or welding a positioning relief 16 to the inner face of the side wall 8 of the battery housing. According to this embodiment, the tapped holes 15 are provided in the lower step 19 of each positioning relief 16.Thus, as illustrated in particular in Figures 4 and 6, a portion of the lower face of each first positioning ring 10 rests on the upper step 18 of one of the two positioning reliefs 16, the height difference between the upper step 18 and the lower step 19 being configured to allow the cantilevered mounting of the first positioning ring 10. As illustrated in [Fig. 6], the first positioning ring 10 is mounted with a clearance J along the vertical axis which is within a predetermined tolerance range. The predetermined tolerance range varies according to the embodiments, in particular depending on the dimensions of the . battery system 2 and its various components. In particular, the predetermined tolerance range can be expected to vary according to the dimensions of the battery cells 4. Depending on the embodiment, the predetermined tolerance range can, for example, be 1 to 6 mm, preferably 2 to 5 mm, and even more preferably 3 to 4 mm. The cantilevered mounting of the first positioning ring 10 on the battery housing 3 with a clearance J along the vertical axis within the predetermined tolerance range limits the vertical displacement of the battery cell 4 while taking into account any mounting tolerances, in particular any flatness defects in the block 6 of battery cells 4.

[0039] As illustrated in Figures 4 and 6, an interlayer element 20 is arranged between each first positioning ring 10 and the upper surface of the battery cells 4. In this case, this interlayer element 20 is formed by an electronic card holder 21 of the battery system 2. According to other embodiments, the interlayer element 20 may be formed by another component of the battery system 2, or no interlayer element 20 may be placed between the first positioning ring 10 and at least one of the battery cells 4. It is understood that, in this case, the interlayer element 20 formed by the electronic card holder 21 extends over the entire upper surface of each battery cell 4, so that the interlayer element 20 is also arranged between each second positioning ring 11 and the upper surface of the battery cells 4.Thus, according to the present embodiment, the first positioning rings 10 and the second positioning rings 11 form an indirect stop for the respective upper faces of the battery cells 4.

[0040] The battery system 2 comprises as many positioning members 17 as there are second positioning rings 11, i.e., nine in this case. This number may vary depending on the embodiment. According to the present embodiment, each positioning member 17 forms a positioning rod that extends vertically from the support plate 24. Each positioning member 17 comprises a free end in which a tapped hole 15 is provided. A second positioning ring 11 is fixed to the free end of each of the positioning members 17 by screwing a positioning screw 14, passing through the central orifice 13 of the second positioning ring 11, into the tapped hole 15 of the positioning member 17.At its end fixed to the support plate 24, each positioning member 17 includes a fixing head 26 intended to be screwed into the support plate 24 so as to fix the positioning member 17 to the support plate 24. According to other embodiments, the positioning member 17 may be fixed differently to the support plate 24, for example by welding or by clipping.

[0041] The invention is not limited to the embodiments shown and other embodiments will be obvious to a person skilled in the art. List of references

[0042] 1: motor vehicle 2: Battery system 3: Battery box 4: battery cell 5: Battery cell subset 6: Battery cell block 7: first lateral edge of the upper face of the battery cell 8: Side panel of the case 9: second lateral edge of the upper face of the battery cell 10: First positioning ring 11: Second positioning ring 12: Main axis of the first and second positioning rings 13: Central orifice passing through the first and second positioning rings 14: Positioning screw 15: tapped hole 16: Positioning relief 17: Positioning device 18: upper step of the positioning relief 19: Lower step of the positioning relief 20: Intercalated element 21: electronic card 22: External thread of the positioning screw 23: washer 24: support plate 25: Reinforcing rib 26: Fixing head A: Main longitudinal axis of the battery system; J: Vertical play of the first positioning ring

Claims

Demands

1. A battery system (2) for a motor vehicle (1), comprising: - a battery case (3) including a support plate (24) and a cover together defining an internal space of the battery system (2), - a stack including several battery cells (4) arranged in the battery case (3) on the support plate (24) and aligned along a principal longitudinal axis (A) of the battery system (2), - positioning means for limiting a displacement of at least one of the battery cells (4) along a vertical axis orthogonal to the principal longitudinal axis (A) of the battery system (2), characterized in that the positioning means include at least one first positioning ring (10) forming a stop for at least a portion of an upper face of the first battery cell (4),the first positioning ring (10) being cantilevered onto the battery housing (3) with a clearance (J) along the vertical axis within a predetermined tolerance range.

2. Battery system (2) according to claim 1, wherein the first positioning ring (10) forms a stop for at least a portion of an upper face of a second of the battery cells (4), the second battery cell (4) being adjacent to the first battery cell (4).

3. Battery system (2) according to claim 1 or 2, wherein the first positioning ring (10) forms a stop for a first lateral edge (7) of the upper face of the first battery cell (4), and wherein the positioning means further comprise at least a second positioning ring (11) forming a stop for a second lateral edge (9) of the upper face of the first battery cell (4), opposite and facing the first positioning ring (10).

4. Battery system (2) according to any one of the preceding claims, further comprising an intercalated element (20) arranged between, on the one hand, the first positioning ring (10) and / or the second positioning ring (11), and, on the other hand, at least a part of the upper face of the first battery cell (4).

5. Battery system (2) according to any one of the preceding claims, wherein a positioning relief (16) projects outward from an inner face of a side wall (8) of the battery housing (3) and forms a support for at least one first positioning ring (10), the positioning relief (16) having a stepped shape comprising an upper step (18) and a lower step (19), a portion of a lower face of the first positioning ring (10) bearing on the upper step (18) of the positioning relief (16), the height difference between the upper step (18) and the lower step (19) being configured to permit cantilever mounting of the first positioning ring (10) with the clearance (J) along the vertical axis within the predetermined tolerance range.

6. Battery system (2) according to claim 5, wherein the positioning relief (16) extends axially along the inner face of the side wall (8) of the housing (3) from a first longitudinal end to a second longitudinal end of the battery housing (3) so as to form a support for several first positioning rings (10).

7. Battery system (2) according to any one of the preceding claims, wherein at least one of the first positioning rings (10) and / or at least one of the second positioning rings (11) comprises a through central orifice (13), the positioning means further comprising means for fixing the first positioning ring (10) and / or the second positioning ring (11) to the battery housing (3) comprising a positioning screw (14) extending through the through central orifice (13) of the first positioning ring (10) and / or the second positioning ring (11) and being screwed into a corresponding tapped hole (15) of the battery housing (3).

8. Battery system (2) according to the preceding claim, wherein at least a portion of an external thread (22) of the positioning screw (14) is coated with threadlocker.

9. Battery system (2) according to claim 7 or 8, wherein the positioning screw (14) is screwed in with a tightening torque

10.

11. between 2 and 8 Nm, preferably between 2 and 5 Nm, preferably even more preferably between 2 and 3 Nm Battery system (2) according to any one of claims 7 to 9, wherein the battery housing (3) comprises at least one positioning member (17) extending vertically projecting from the support plate (24), the positioning member (17) comprising a free end in which a tapped hole (15) is provided, a second positioning ring (11) being fixed to the free end of the positioning member (17) by screwing a positioning screw (14), passing through the central orifice (13) of the second positioning ring (11), into the tapped hole (15) of the positioning member (17). Battery system (2) according to any one of the preceding claims, wherein the first positioning ring (10) and / or the second positioning ring (11) has a shape with rotational symmetry about its main axis (12).

Images