Power battery for motor vehicle

Abstract

The invention relates to a power battery (1) for a motor vehicle, comprising: a plurality of rechargeable battery cells (2); a battery cell connector (3) which electrically connects the rechargeable battery cells (2) to each other; and an assembly plate (4) that is mounted on the rechargeable battery cell (2) and receives the battery cell connector (3). The battery cell connector (3) is provided with waves (5), and the waves are arranged on ridge-shaped protrusions (6) of the assembly plate (4); the gap between the wave (5) and the ridge-shaped protrusions (6) of the assembly plate is smaller than 1 mm.

Description

Technical Field

[0001] The present disclosure relates to a power battery for a motor vehicle and a motor vehicle having the power battery. Background Art

[0002] A traction battery, also called a high-voltage battery, a traction battery or a circulating battery, is a rechargeable battery that is primarily intended to supply electrical energy to the electric motor responsible for propulsion in electric vehicles. Traction batteries are also included in fuel cell vehicles and as buffer batteries in hybrid drives.

[0003] Such traction batteries have from a few to thousands of rechargeable battery cells or battery cell blocks connected to one another in series and in parallel. So-called battery cell connectors or busbars are used to connect or electrically connect the individual rechargeable battery cells to one another.

[0004] In this context, DE102009050316A1 proposes to implement a battery cell connector, which is used to conductively connect a first battery cell terminal of a first electrochemical battery cell of an electrochemical device to a second battery cell terminal of a second electrochemical battery cell, wherein the battery cell connector allows a reliable and operationally safe connection of the battery cell terminals, and the battery cell connector includes a first contact section for connecting to the first battery cell terminal, a second contact section for connecting to the second battery cell terminal, and an elastically and / or plastically deformable compensation area, which connects the first contact section and the second contact section to each other and allows these contact sections to move relative to each other.

[0005] DE102018219478A1 describes a method for materially connecting a terminal of a battery cell to at least one battery cell connector by means of resistance welding, wherein a first electrically conductive battery cell connector is placed on the terminal of the battery cell, and a first welding electrode is placed on the first battery cell connector, and a second welding electrode is placed in electrical contact with the terminal, so that a welding current flows from the first welding electrode through the first battery cell connector and through the terminal to the second welding electrode, whereby the first battery cell connector is connected to the terminal of the battery cell by means of resistance welding. Summary of the invention

[0006] Against the background of this prior art, the object of the present disclosure is to provide a device which is suitable for improving the prior art.

[0007] The object is achieved by the features of the independent claims. The dependent claims and the independent claim contain optional developments of the invention.

[0008] Accordingly, the object is solved by a power battery for a motor vehicle. Here, the power battery can be a power battery of the same type as described at the beginning. It is conceivable that the power battery can provide a voltage in the range of 400V to 800V.

[0009] The power battery includes: a plurality of rechargeable battery cells; a battery cell connector that electrically connects the rechargeable battery cells to each other; and an assembly plate that is mounted on the rechargeable battery cells and receives the battery cell connector.

[0010] Rechargeable battery cells are to be understood as electrochemical battery cells which are designed to be repeatedly charged with electrical energy, to store this energy and to release the stored energy during operation of the traction battery.

[0011] A battery cell connector is a component made of an electrically conductive material which connects individual rechargeable battery cells to one another in series and / or in parallel.

[0012] The assembly plate can be a component made of plastic, for example, by injection molding, and is therefore non-conductive. The assembly plate is used to position the cell connector relative to the rechargeable battery cells during assembly of the power battery. During operation of the power battery, the assembly plate mechanically supports the cell connector.

[0013] The battery cell connector has waves that rest on ridges of the assembly plate.

[0014] In other words, the cell connector has a stiffness that is reduced by the waves, which serves to compensate for tolerances and operating loads (cell expansion, vibrations, thermal expansion). The waves thus reduce the forces acting on the connection points (eg weld seams) to the cell.

[0015] A wave may be understood to mean a section in which the battery cell connector has a substantially U-shaped cross section.

[0016] The gap between the waves and the ridges of the assembled plate is less than 1 mm, optionally less than 0.5 mm or less than 0.3 mm.

[0017] The gap between the corrugation and the assembly plate is therefore so small that during the foaming of the power cell no foam can enter or flow between the corrugation and the assembly plate and then harden between these two components. This allows this subregion, which is thinner than the rest of the cell connector, to be mechanically self-protected, since no mechanical connection of the cell connector to the assembly plate is produced there.

[0018] Possible configurations of the traction battery described above are explained in more detail below.

[0019] The cell connector can have a cross-sectional taper in the region of the wave in order to thereby form a fuse. Thus, during operation of the traction battery, the propagation of so-called “thermal runaway” between the cell cells can be avoided.

[0020] The cross-sectional taper can be formed by a through-hole in the region of the wave. This is a space-saving solution for forming a fuse.

[0021] In particular, the assembly plate can have a rectangular parallelepiped block which is arranged in the through-hole and which projects beyond the wave in a direction perpendicular to the rechargeable battery cells.

[0022] The block of the assembly plate can thus protrude in a space-saving manner through the opening in the wave (also referred to as “fuse”) and thus protect the relatively mechanically sensitive component from loads.

[0023] The gap between the wave and the cuboid-shaped mass of the assembled plate may be less than 1 mm.

[0024] Therefore, the gap between the wave and the assembly plate is also so small that when the power cell is foamed, no foam can enter or flow between the wave and the block of the assembly plate and then harden between these two components. The mechanical self-protection of this subregion, which is thinner than the rest of the battery cell connector, which has been described above, can be further achieved, because no mechanical connection of the battery cell connector to the assembly plate is produced here either.

[0025] The cross-sectional taper can be dimensioned such that the wave reaches a temperature of more than 80° C., optionally more than 100° C., during operation of the power battery.

[0026] At the fuse or wave, the mechanical properties of the material of the battery cell connector can be reduced in an advantageous manner due to such high temperatures, since the material becomes softer and therefore less load acts on the connection point of the battery cell connector to the respective battery cell. In addition, due to such temperatures, material phenomena can occur, which can further positively influence the mechanical properties and service life. For example, an increased creep tendency can be caused, so that mechanical stresses can be dissipated, especially through long-term changes (such as tolerances and expansions). Small cross sections in the region of the wave can increase the effectiveness of the wave as a compensation element.

[0027] The power battery can have a housing and a polymer foam, with which the battery cell connector is foamed relative to the housing.

[0028] In other words, foaming of the rechargeable battery cells and / or the battery cell connectors relative to the (high voltage storage) housing is conceivable. In particular, in conjunction with waves reaching high temperatures during operation (e.g., from more than 100° C. up to 150° C.), it can be said that the foam that is latently and / or partially attached can burn or melt freely through the power battery according to the present disclosure. This means that the foam loses its mechanical properties (e.g., from the glass transition temperature of the polyurethane material of approximately 80° C.). As a result, the waves themselves can be protected from this disadvantageous additional mechanical load input.

[0029] It is conceivable that the gap between the wave and the housing has the gap size already specified above, ie less than 1 mm, optionally less than 0.5 mm or less than 0.3 mm.

[0030] The gap between the wave and the housing, in particular the housing upper part, is therefore so small that during foaming of the power cell no foam can enter or flow between the wave and the housing and then harden between these two components. The mechanical self-protection already described above of this subregion, which is thinner than the rest of the cell connector, can thus be further achieved, since no mechanical connection of the cell connector to the housing is produced here either.

[0031] The battery cell connector can be welded to each individual rechargeable battery cell. It is conceivable that the assembly plate is made of plastic.

[0032] Furthermore, a motor vehicle is provided, which has the power battery described above.

[0033] The motor vehicle can be a single-track or double-track motor vehicle. It is conceivable that the motor vehicle is a passenger vehicle (eg a passenger car) and / or a commercial vehicle (eg a truck).

[0034] The power battery can be connected to an electric motor of the motor vehicle and is configured to supply the electric motor with electrical energy during operation of the power battery. The electric motor can be configured to drive the motor vehicle with the electrical energy obtained from the power battery.

[0035] The above descriptions of the traction battery also apply analogously to the motor vehicle, and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Refer to the following Figure 1 An implementation method is described.

[0037] Figure 1 A traction battery for a motor vehicle is schematically shown in a top view, wherein a partial region of the traction battery is depicted enlarged for illustrative purposes. DETAILED DESCRIPTION

[0038] exist Figure 1 A Cartesian coordinate system is described in which the X axis of the coordinate system extends along the longitudinal direction X of the vehicle, the Y axis of the coordinate system extends along the width direction Y of the vehicle, and the Z axis of the coordinate system extends along the height direction Z of the vehicle. The three axes or directions are perpendicular to each other. The longitudinal direction X of the vehicle and the width direction Y of the vehicle form an essentially horizontal plane, and the height direction Z of the vehicle, which extends essentially parallel to the vertical line, is perpendicular to the horizontal plane. The longitudinal direction X of the vehicle extends from the front to the rear of the vehicle (not described further).

[0039] As in Figure 1 As can be seen on the right side of the top view in the figure, the power battery 1 for a motor vehicle includes: a plurality of rechargeable battery cells 2; a plurality of battery cell connectors 3, which electrically connect the rechargeable battery cells 2 to each other accordingly; and an assembly plate 4 constructed as an injection-molded component, which is mounted on each rechargeable battery cell 2 and receives each battery cell connector 3.

[0040] As especially by Figure 1 The left-hand illustration in FIG. 1 (which depicts an enlarged detail of the power battery 1 ) shows that the battery cell connector 3 has a wave or corrugated section 5 for each connection location 9 (in the present case a welded connection) to one of the rechargeable battery cells 2 , which is arranged on a ridge-like protrusion 6 of the assembly plate 4 .

[0041] In order to mechanically decouple the waves 5 and therefore the battery cell connector 3 in the section formed with the waves 5 from the ridges 6 and therefore from the assembly plate 4, a circumferential gap is provided between the waves 5 and the ridges 6 of the assembly plate 4, but this gap produces a spacing of less than 1 mm between the ridges 6 and the waves 5.

[0042] The cell connector 3 has a through-opening 7 in the region formed with the ripples 5 , so that a cross-sectional taper of the cell connector 3 is achieved in this region in the vehicle width direction Y and the region formed with the ripples 5 serves as a fuse.

[0043] A substantially cuboid block 8 is formed in a space-saving manner in the through-opening 7 as part of the assembly plate 4 , which protrudes beyond the corrugations 5 in the vehicle height direction Z and thus prevents or at least reduces the introduction of loads onto the corrugations 5 from above.

[0044] Like the gaps between the waves 5 and the ridges 6 , gaps are also formed between the waves 5 and the rectangular blocks 8 of the assembly plate 4 . The gaps are smaller than 1 mm, and the waves 6 are mechanically decoupled from the blocks 8 of the assembly plate 4 .

[0045] The power cell 1 described above is provided with a housing (not described) during assembly, and a liquid polymer foam (e.g., with polyurethane) is introduced between the housing, in particular the upper part of the housing, and the power cell 1, which expands and hardens. Due to the small gap dimensions between the waves 5 and the ridges 6 of the assembly plate 4 and the blocks 8, no polymer foam enters these gaps, and the mechanical decoupling remains even after foaming. It is also conceivable to select the gap between the waves 5 and the housing as described above, i.e., less than 1 mm, so that no polymer foam enters between the waves 5 and the housing, and a mechanical decoupling also exists here.

[0046] This mechanical decoupling relieves the cell connector 3 in particular and prevents component failures during the subsequent driving operation of the motor vehicle. In order to ensure the mechanical decoupling, the through-hole 7 forming the cross-sectional taper is also dimensioned such that the waves reach a temperature of more than 80° C. during operation of the power battery 1 . As a result, the polymer foam substantially loses its adhesion in the region of the waves 5 and the waves 5 are exposed and supported in the polymer foam. Reference numerals list

[0047] 1 Power battery

[0048] 2 rechargeable battery cells

[0049] 3 battery cell connector

[0050] 4 Assemble the board

[0051] Wave 5

[0052] 6 Ridges

[0053] 7 Through Holes

[0054] 8 blocks

[0055] 9Connection parts

[0056] X Longitudinal direction of vehicle

[0057] Y Vehicle width direction

[0058] Z vehicle height direction

Claims

1. A power battery (1) for a motor vehicle, the power battery (1) comprising: - a plurality of rechargeable battery cells (2); - a battery cell connector (3), which electrically connects the rechargeable battery cells (2) to each other; and - an assembly plate (4) mounted on the rechargeable battery cell (2) and receiving the battery cell connector (3); It is characterized in that - the battery cell connector (3) has a wave (5) which is placed on a ridge-like protrusion (6) of the assembly plate (4); and - The gap between the waves (5) and the ridges (6) of the assembled plate is less than 1 mm.

2. The power battery (1) according to claim 1, characterized in that: The battery cell connector has a cross-sectional taper in the region of the wave (5) in order to thereby form a fuse.

3. The power battery (1) according to claim 2, characterized in that: The cross-sectional taper is formed by a through-opening (7) in the region of the waves (5).

4. The power battery (1) according to claim 3, characterized in that: The assembly plate (4) has a rectangular parallelepiped block (8) which is arranged in the through hole (7) and protrudes beyond the wave (5) in a direction (Z) perpendicular to the rechargeable battery cell (2).

5. The power battery (1) according to claim 4, characterized in that: The gap between the wave (5) and the rectangular block (8) of the assembly plate (4) is less than 1 mm.

6. The power battery (1) according to any one of claims 2 to 5, characterized in that: The cross-sectional taper has such a size that the wave (5) reaches a temperature of more than 80° C. during operation of the power battery (1).

7. The power battery (1) according to any one of claims 1 to 6, characterized in that: The power battery (1) comprises a housing and polymer foam, and the battery cell connector (3) is foamed with the polymer foam relative to the housing (1).

8. The power battery (1) according to any one of claims 1 to 7, characterized in that: The battery cell connector (3) is welded to each single rechargeable battery cell (2).

9. The power battery (1) according to any one of claims 1 to 8, characterized in that: The assembly plate (4) is made of plastic.

10. A motor vehicle, characterized in that: The motor vehicle comprises a traction battery (1) according to any one of claims 1 to 9.

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