Battery assembly for a motor vehicle

Abstract

The invention relates to a battery assembly for a motor vehicle, having a battery housing (14) and at least one battery cell module (12) arranged on a floor (16) of the battery housing (14). The at least one battery cell module (12) comprises a battery cell module housing (22) and a plurality of battery cells (24) arranged in the battery cell module housing (22). A bottom (26) of the battery cell module housing (22) is connected to the floor (16) of the battery housing (14) by means of an adhesive (28). The battery cell module housing (22) is connected to a side wall (18) of the battery housing (14) by means of a further adhesive (30). In this case, the further adhesive (30) has a higher shear strength than the adhesive (28) arranged between the bottom (26) of the battery cell module housing (22) and the floor (16) of the battery housing (14).

Description

Technical Field

[0001] This invention relates to a battery assembly for a motor vehicle, comprising a battery housing and at least one battery cell module disposed on a base plate of the battery housing. The at least one battery cell module includes a battery cell module housing and a plurality of battery cells disposed within the battery cell module housing. The bottom of the battery cell module housing is attached to the base plate of the battery housing by means of an adhesive. Background Technology

[0002] CN 112151910 A describes a liquid-cooled vehicle battery system in which a battery module is housed within a housing. The housing includes a frame surrounding the battery module and a heat sink connected to the frame. The battery module is mounted on the heat sink within the frame. The battery module is bonded to the heat sink using a thermally conductive structural adhesive. The frame is also connected to the top side of the heat sink using structural adhesive, with additional welded portions provided in the corner regions of the frame.

[0003] Alternatively, in battery assemblies used in motor vehicles, it can be specified that the battery cell modules are threadedly connected to the battery housing. In this case, thermal paste can be applied between the bottom of the battery cell module housing and the base plate of the battery housing. The battery cell module can be connected to the battery housing by inserting screws into screwdrivers located laterally next to the respective battery cell module housing. However, this design creates a gap next to the battery cell module to allow access to the screws with a screwdriver. This is disadvantageous.

[0004] In addition, the connection between the battery cell module and the battery casing, which can only be made laterally, is not ideal, especially when the battery cell module is relatively heavy, as may be the case in battery cell modules used in automotive battery assemblies.

[0005] Furthermore, in battery cell module structures where the battery cell module is threadedly connected to the battery housing via screw-on strips, the respective battery cell module only provides a relatively unuseful side profile in terms of lateral pressing into the battery housing. This results in a correspondingly low drag torque in the battery assembly. Correspondingly, with the battery cell module threadedly connected to the battery housing, the mechanical rigidity of the respective battery cell module cannot be optimally utilized for the overall mechanical performance of the battery assembly.

[0006] Furthermore, applying more expensive thermal paste between the bottom of the battery cell module housing and the battery housing base plate incurs higher costs. Additionally, the large amount of thermal paste in this case disadvantageously results in a correspondingly larger battery assembly weight.

[0007] Tolerances must be considered in the design of the gap or void between the bottom of the battery cell module housing and the battery housing base plate. This results in a relatively large gap or void between the bottom of the battery cell module housing and the battery housing base plate. Correspondingly, a relatively large amount of expensive thermal paste must be used to fill this gap or void as much as possible. This is disadvantageous in terms of the cost and weight of the battery assembly, as mentioned earlier. Summary of the Invention

[0008] The object of the present invention is to provide a battery assembly of the type described in the preamble, wherein the at least one battery cell module is better mechanically connected to the battery housing.

[0009] This task is accomplished by a battery assembly having the features of claim 1. Advantageous designs with suitable inventive improvements are indicated in the dependent claims and the following description.

[0010] The battery assembly for a motor vehicle according to the present invention includes a battery housing and at least one battery cell module. The at least one battery cell module is mounted on a base plate of the battery housing. The at least one battery cell module includes a battery cell module housing and a plurality of battery cells disposed within the battery cell module housing. The bottom of the battery cell module housing is attached to the base plate of the battery housing by means of an adhesive. Additionally, the battery cell module housing is attached to the sidewalls of the battery housing by means of another adhesive. In this case, the other adhesive has a higher shear strength than the adhesive disposed between the bottom of the battery cell module housing and the base plate of the battery housing.

[0011] Accordingly, at least one battery cell module is mechanically connected to the battery housing by another adhesive disposed between the battery housing sidewall and the battery cell module housing. That is, the other adhesive, with higher shear strength, bears the main load in terms of mechanical requirements. Thus, at least one battery cell module is mechanically connected to the battery housing in an improved manner in this battery assembly.

[0012] In contrast, the lower shear strength of the adhesive allows for easy separation of at least one battery cell module housing from the battery casing when disassembly is required. This is achieved, although another adhesive must first be disconnected. This is easily accomplished, for example, by using a reciprocating cutting tool, such as a vibrating blade.

[0013] After cutting the adhesive layer formed by the other adhesive, at least one battery cell module can then be easily removed from the battery casing, for example, with the aid of a removal tool. Removing at least one battery cell module from the battery casing is particularly simple because the adhesive has only low shear strength.

[0014] Cost savings and weight reduction are particularly advantageous because it eliminates the need to thread at least one battery cell module onto the battery housing and, especially, the sidewalls of the battery housing. This is achieved through efficient mechanical connection of the battery cell modules into the overall battery structure, and especially through the use of another adhesive with high shear strength.

[0015] Furthermore, this method allows for a particularly small gap or void between the bottom of at least one battery cell module housing and the battery housing base plate. This is especially applicable compared to battery assemblies where at least one battery cell module is threaded to the battery housing. Because at least one battery cell module is directly mounted to the battery housing base plate using adhesive, a shorter tolerance chain can be achieved. This saves on the cost and amount of adhesive, contributing to weight reduction in the battery assembly.

[0016] If the battery assembly is used in a motor vehicle, wherein a high-voltage battery is preferably provided by at least one battery cell module of the battery assembly, such weight reduction is particularly advantageous for the vehicle’s CO2 balance.

[0017] Furthermore, due to the small clearance tolerance between the bottom of the battery cell module housing and the battery housing base plate, the battery cells housed within the battery cell module housing can achieve particularly effective cooling during operation. This, in particular, can improve the fast-charging capability of the battery cells.

[0018] The clearance tolerances in the battery assembly advantageously arise solely from the surface shape tolerances of the bonding surfaces provided by the battery housing base plate and the bonding surfaces provided by at least one battery cell module housing base plate. This allows the battery assembly to be manufactured with relatively little adhesive.

[0019] Furthermore, in terms of structural space, the connection of at least one battery cell module to the battery housing is improved because there is no need to create a gap for a screwdriver to approach the screw. This is because a separate adhesive is used to connect the battery cell module housing to the battery housing without threading at least one battery cell module to the battery housing.

[0020] Alternatively, the battery cell module housing may contribute effectively to the mechanical properties of the entire battery or battery assembly. Furthermore, force paths can be formed and effectively utilized within the battery assembly using a simple solution. However, the at least one battery cell module can still be easily disassembled, just as when it is attached to the battery housing using screws or bolts.

[0021] The shear strength of the adhesive is preferably in the range of about 0.1 MPa to about 2 MPa. Furthermore, it has been shown to be advantageous that the shear strength of the other adhesive is in the range of about 5 MPa to about 15 MPa. This is particularly advantageous because it allows for the application of a large holding force even when the bonding surface for attaching the battery cell module housing to the sidewall of the battery housing using another adhesive is small. The relatively low shear strength or low tensile strength of the adhesive also ensures that the battery cell module can be removed without damage by pulling it upwards during maintenance or for recycling. Attached Figure Description

[0022] Other advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and in conjunction with the figures. The features and combinations of features mentioned above in the specification, as well as the features and combinations of features mentioned below in the description of the drawings and / or shown individually in the figures, may be used not only in their respective specified combinations, but also in other combinations or individually, without departing from the scope of the invention, wherein:

[0023] Figure 1 The battery assembly is shown in a highly schematic manner, in which individual battery modules are bonded to the battery housing of the battery assembly using two adhesives with different shear strengths;

[0024] Figure 2 Schematic illustration based on Figure 1 A portion of the battery assembly;

[0025] Figure 3 This schematically illustrates another part of the battery assembly and a tool for removing the battery cell module from the battery housing.

[0026] In the figure, identical or functionally identical parts are marked with the same reference numerals. Detailed Implementation

[0027] Figure 1 The battery assembly 10 is shown schematically, in which a battery cell module 12 is disposed within a battery housing 14. The battery housing 14 includes a recessed portion having a base plate 16 and sidewalls 18 surrounding the base plate 16. The sidewalls 18 may, as exemplarily shown herein, be designed to be integral with the base plate 16 of the battery housing 14. Additionally, the battery housing 14 includes a cover 20, which is connected to the recessed portion in a manner not shown in detail herein. The at least one battery cell module 12 is disposed within a cavity defined by the recessed portion and the cover 20.

[0028] At least one battery cell module 12 here comprises a battery cell module housing 22 and battery cells 24 arranged inside the battery cell module housing 22, which are not shown in detail herein. In practice, these battery cells 24 of the battery cell module 12 are electrically conductively connected to each other, wherein the battery cells 24 of each battery cell module 12 can be electrically connected in series and / or in parallel.

[0029] Particularly when the battery assembly 10 is intended to provide a high-voltage battery for a motor vehicle, that is, an accumulator for a traction battery of a motor vehicle which is preferably designed to have a rated voltage higher than 60 volts and especially up to hundreds of volts, a plurality of battery cell modules 12 can be electrically conductively connected within the battery housing 14.

[0030] The battery cell module housing 22 comprises a bottom portion 26, which faces a bottom plate 16 of the battery housing 14. An adhesive compound 28 is provided between the bottom portion 26 and the bottom plate 16. The adhesive compound 28 is preferably designed to be thermally conductive, so that heat dissipated by the battery cells 24 during operation can be well transferred to the battery housing 14 or a corresponding cooling mechanism via the adhesive compound 28. For example, the thermal conductivity of the adhesive compound 28 may be about 2W / mK and particularly in a range from 2W / mK to 2.5W / mK.

[0031] Although the adhesive compound 28 is used for reliably fixing the battery cell module 12 in the battery housing 14, the shear strength or holding force of the adhesive compound 28 is preferably specified such that the battery cell module 12 can be easily separated from the battery housing 14, especially the bottom plate 16, in case of maintenance or replacement of at least one battery cell module 12. The adhesive compound 28 preferably has minimal adhesiveness, so that collision requirements and working strength requirements can be satisfied. However, due to the relatively low shear strength or tensile strength of the adhesive compound 28, non-destructive removal of the battery cell module 12 from the battery housing 14 and especially taking it out from the groove-shaped receiving portion of the battery housing 14 is still ensured.

[0032] Different from the adhesive compound 28 serving as a thermally conductive adhesive, another adhesive 30 is used for structurally connecting at least one battery cell module 12 to the battery housing 14. By means of the Figure 1 another adhesive 30 schematically shown herein, the battery cell module housing 22 is connected herein to a side wall 18 of the battery housing 14. The another adhesive 30 has a high shear strength, for example, which can particularly be in a range of 8MPa to 14MPa. In comparison, the shear strength or tensile strength of the adhesive compound 28 may particularly be in a range of about 0.5MPa to 1.5MPa, for example.

[0033] Both the shear strength or tensile strength of the another adhesive 30 serving as a fixing adhesive and the shear strength or tensile strength of the adhesive compound 28 serving as a thermally conductive adhesive can be determined particularly according to DIN EN ISO 527-2.

[0034] To stably secure the at least one battery cell module 12 within the battery housing 14, another adhesive 30 is disposed beside the battery cell module 12, particularly between the side wall 32 of the battery cell module housing 22 and the side wall 18 of the groove-shaped receiving portion of the battery housing 14. To facilitate disassembly of the battery cell module 12, the other adhesive 30, having high shear strength, can be broken, for example, by means of a vibrating cutter. This is particularly easy because the side of the battery cell module housing 22 allows for good access to such a cutting tool.

[0035] Preferably, the adhesive 28 covers the bottom 26 of the battery cell module housing 22 in a substantially planar shape. To ensure that the adhesive 28 is flat and fills the gaps or seams between the bottom plate 16 of the battery housing 14 and the bottom 26 of the battery cell module housing 22 as evenly as possible, boundary members can be provided to define the corresponding bonding surfaces.

[0036] For example, a boundary element designed as a sealing strip or sealing band 34 thus defines the edge of the surface occupied by the adhesive 28 on the base plate 16 of the battery housing 14. In this case, the sealing band 34 or an equivalent boundary element may be placed on the battery cell module 12 and / or the base plate 16 before at least one battery cell module 12 is installed into the battery housing 14.

[0037] Foam materials are particularly suitable for providing such boundary elements. When the conductive connection between the battery cell module 12 and the base plate 16 needs to be specified, such foam materials can also be coated with metal. Accordingly, the foam material can be surrounded by the conductive metal of the boundary element.

[0038] You can also from Figure 1 As seen in the diagram, the battery cell module 12 can have an energy-absorbing element 36, thereby providing a collision geometry. Such an energy-absorbing element 36 can absorb collision energy through deformation when the battery assembly 10 is subjected to lateral forces, thus preventing damage, especially to the battery cell 24. Figure 1 In the schematic design, another adhesive 30 is arranged between the outer side 38 of the energy absorber 36 and the side wall 18 of the groove-shaped receiving portion of the battery housing 14.

[0039] Figure 2 An exemplary design is shown of an energy absorber 36, which is specifically designed to be integral with the sidewall 32, in the form of a cavity.

[0040] In comparison, it can be seen from Figure 3 The image shows a possible design for the circumferential flange 40, which may correspond to the groove-shaped receiving portion of the battery housing 14. The cover 20 of the battery housing 14 (see...) Figure 1 It can be fixed, in particular, to this circumferential flange 40.

[0041] Figure 3 Also schematically shown is a removal device 42, which can be used to remove the battery cell module 12 from the battery housing 14 after the adhesive 30 is broken. Therefore, by operating this removal device 42, the bottom 26 of the battery cell module housing 22 can be separated from the bottom plate 16 of the battery housing 14 (see figure). Figure 1 Separation of the battery cell module 12. The removal device 42 can be operated after another adhesive 30 has been disconnected, which is used to structurally attach the battery cell module 12 to the battery housing 14 and can therefore be called a fixing adhesive.

[0042] For example, the removal device 42 may include a screw 44, which, by rotating the screw 44, can remove the bottom 26 of the battery cell module housing 22 and thus the entire battery cell module 12 from the bottom plate 16 of the battery housing 14 (see...). Figure 1 The battery cell module 12 can be easily removed from the slot-shaped receiving portion of the battery housing 14 when such a removal device 42 is provided.

[0043] By providing an adhesive in the form of a preferred thermally conductive adhesive 28 with different shear strengths and another adhesive 30 serving as a fixing adhesive, two mutually coordinated connection designs are achieved here. These mutually coordinated connection designs provide sufficient holding force to secure the battery cell block or battery cell module 12 within the battery housing 14 to meet the requirements of normal use of the battery assembly 10, but also meet the requirements for special events such as accidents involving vehicles equipped with the battery assembly 10.

[0044] Furthermore, there is a possibility of non-destructive disassembly of at least one battery cell module 12 and continued use of the individual component in maintenance situations, without the need for laborious surface cleaning. In addition, sufficient heat dissipation is ensured from the battery cells 24 of the battery cell module 12 to the battery housing 14, and especially the integrated cooling mechanism.

[0045] Possible parameters for the connection design provided by the thermally conductive adhesive or bonding agent 28 should be explained, for example, as follows. Therefore, the bonding agent 28 can be an adhesive obtained from Sika GmbH, Germany, which can be marketed under its trademark... -953L30 is obtained. In this case, it is a two-component adhesive containing a silane-terminated polymer. This adhesive has a tensile strength of 0.5 MPa to 1.5 MPa and a viscosity of 30 + / - 20 Pa·s. The thermal conductivity of this adhesive or binder 28 is in the range of 2 W / mK to 2.5 W / mK. Furthermore, when using this material, the elongation at break of binder 28 is approximately 20% to 50% according to DIN EN ISO 527-2.

[0046] The adhesive 28 can be applied extensively / over a large area to the substantially horizontal surface between the base plate 16 of the battery housing 14 and the bottom 26 of at least one battery cell module 12. However, the surface of the base plate 16 to which the adhesive 28 is applied does not need to be perfectly horizontal. In particular, a deviation of +10° to -10° from the horizontal plane is possible.

[0047] Preferably, the joint or gap between the base plate 16 and the bottom 26 is as small as possible to ensure good heat dissipation. In particular, the size of the gap can be in the range of 0.5 mm to 3 mm.

[0048] At this connection point, the adhesive 28 is arranged as comprehensively as possible between the bottom plate 16 of the battery housing 14 and the bottom 26 of the corresponding battery cell module housing 22, so as to achieve uniform heat transfer on the one hand and uniform fixation of the battery cell module 12 on the other hand.

[0049] In contrast, for structural bonding using another adhesive 30, a two-component adhesive in the form of a polyurethane glue, such as BETAFORCE purchased from DuPont, can be used. TM The adhesive is 9050, and may accordingly have the identification number BF9050. This adhesive has a viscosity of less than 1 Pa·s and a thermal conductivity of less than 0.3 W / mK.

[0050] Furthermore, the elongation at break of this adhesive is in the range of 150% to 250% according to DIN EN ISO 527-2. Additionally, this adhesive has a Shore hardness of approximately less than 100 Shore A and heat resistance up to approximately 800 degrees Celsius.

[0051] Another adhesive 30 is preferably applied to a substantially vertical surface between the two longitudinal sides of the battery cell block or battery cell module 12 and the battery housing 14, specifically the sidewall 18. However, this surface does not need to be perfectly vertical, but may have a deviation of +10° to -10°, particularly in the vertical direction.

[0052] The joint into which another adhesive 30 is added preferably has a thickness of at least 1.5 mm, taking all relevant tolerances into account. This allows a cutting tool, such as a vibratory tool, to be inserted into the area to separate the adhesive in repair situations.

[0053] Preferably, the other adhesive 30 meets the strength requirement of having a shear strength of at least 8 MPa. In this way, the other adhesive 30 can exert a large holding force even over a small area.

[0054] In particular, compared to the area covered by the adhesive 28 on the bottom 26 of the battery cell module housing 22, the area covered by the adhesive 30 on the side wall 32 of the battery cell module housing 22 is very small, and preferably many times smaller. Providing a correspondingly small area occupied by the adhesive 30 is advantageous because it allows for the use of shorter cutting tools with lower cutting force, or for the adhesive 30 to be cut off and the subsequent removal of the battery cell module 12 within a short processing time.

[0055] Additionally, a large area in the sidewall 32 region of the battery cell module 12 is provided for measures to address potential failures of the battery cells 24. For example, lateral vents or openings can be easily provided on the battery cell module 12 or the battery cell block, or an open air gap can be provided in the sidewall 32 region. In particular, this measure allows gas or fluid flowing from at least one of the battery cells 24 to be directed, specifically directed, to a corresponding opening in the battery casing 14 in the event of a thermal event.

[0056] Furthermore, these two connection designs are preferably separated by a sealing strip 34 or a corresponding sealing lip and / or foam strip, i.e., the structural connection achieved by another adhesive 30 can be effectively broken. Additionally, for example, as shown... Figure 1 The boundary element in the form of the sealing strip 34 shown in the example is used to keep the thermally conductive adhesive or bonding agent 28 within the horizontal plane.

[0057] If cleaning of the adhesive joints is required, different methods can be used. For example, adhesive 28 can be easily removed manually from the bottom side of the battery cell module 12 or the battery cell module housing 22, or from the top side of the base plate 16, using a simple plastic scraper. Residue of the other adhesive 30 used as a lateral fixing adhesive can be mechanically removed using a simple sharp tool. Furthermore, in maintenance cases, it is not necessary to completely remove the adhered residual adhesive. Instead, here it is only necessary to consider the gap height to be set for re-adding adhesive 28 or the gap width to be set for re-adding the other adhesive 30.

[0058] As an alternative to the products exemplified above for providing adhesive 28 and another adhesive 30, products such as those from Polytec PT LLC, such as the VP2108 type, can be used for the thermally conductive adhesive or adhesive 28, which has a strength or shear strength of 0.5 MPa at a thermal conductivity of approximately 2.5 W / mK. Other thermally conductive adhesives can also be obtained from Polytec PT LLC to provide adhesive 28, such as epoxy resin-based boron nitride filler adhesives, identification number TC433.

[0059] Alternatively, products for providing adhesive 28, such as ST25 or ST30 types, can be obtained from the company Copaltec. Such polyurethane potting compounds also advantageously possess low strength or shear strength in the range of 2 MPa at a thermal conductivity of approximately 1.5 W / mK.

[0060] For the other adhesive 30 used as a fixing adhesive, products from Rühl, such as Purocast 765, can be used, with shear strengths ranging from 3 MPa to 10 MPa.

[0061] In addition, to provide another adhesive 30, a product of the PU 10Guss type from L&L Products Company, which has a shear strength of approximately 10 MPa, can be used.

[0062] List of reference numerals

[0063] 10 Battery Assembly

[0064] 12 battery cell modules

[0065] 14 Battery casing

[0066] 16 base plate

[0067] 18 Sidewalls

[0068] 20. Shell Cap

[0069] 22 Battery cell module housing

[0070] 24 battery cells

[0071] 26 Bottom

[0072] 28 Adhesives

[0073] 30 Shell Cap

[0074] 32 Sidewalls

[0075] 34 Sealing tape

[0076] 36 Energy-absorbing components

[0077] 38. Outer surface

[0078] 40 circumferential flange

[0079] 42 Removal device

[0080] 44 screw

Claims

1. A battery assembly for a motor vehicle, comprising a battery housing (14) and at least one battery cell module (12) disposed on a base plate (16) of the battery housing (14), wherein, The at least one battery cell module (12) includes a battery cell module housing (22) and a plurality of battery cells (24) disposed in the battery cell module housing (22), wherein the bottom (26) of the battery cell module housing (22) is connected to the base plate (16) of the battery housing (14) by means of an adhesive (28). Its features are, The battery cell module housing (22) is attached to the side wall (18) of the battery housing (14) by means of another adhesive (30), wherein the other adhesive (30) has a higher shear strength than the adhesive (28) disposed between the bottom (26) of the battery cell module housing (22) and the bottom plate (16) of the battery housing (14).

2. The battery assembly according to claim 1, characterized in that, The shear strength of the adhesive (28) is in the range of 0.1 MPa to 2 MPa and / or the shear strength of the other adhesive (30) is in the range of 5 MPa to 15 MPa.

3. The battery assembly according to claim 1 or 2, characterized in that, The adhesive (28) has higher thermal conductivity than the other adhesive (30).

4. The battery assembly according to claim 1 or 2, characterized in that, The sidewall (18) is designed to be integrated with the base plate (16) of the battery casing (14).

5. The battery assembly according to claim 1 or 2, characterized in that, The adhesive (28) covers the bottom (26) of the battery cell module housing (22) in a substantially planar form, wherein the area of ​​the bottom (26) of the battery cell module housing (22) covered by the adhesive (28) is much larger than the area of ​​the sidewall (32) of the battery cell module housing (22) covered by the other adhesive (30).

6. The battery assembly according to claim 1 or 2, characterized in that, The area occupied by the adhesive (28) on the bottom plate (16) of the battery housing (14) is defined at the edge by a boundary member arranged between the bottom plate (16) of the battery housing (14) and the bottom (26) of the battery cell module housing (22).

7. The battery assembly according to claim 6, characterized in that, The boundary element is designed as a sealing strip and / or sealing band (34).

8. The battery assembly according to claim 1 or 2, characterized in that, The battery cell module housing (22) includes an energy-absorbing element (36) having an outer side (38) facing the sidewall (18) of the battery housing (14), wherein another adhesive (30) is disposed between the outer side (38) of the energy-absorbing element (36) and the sidewall (18).

9. The battery assembly according to claim 1 or 2, characterized in that, The sidewall (18) and the bottom plate (16) provide a groove-shaped receiving portion for the battery housing (14), wherein the battery housing (14) includes a cover (20) connected to the receiving portion.

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