Battery for a motor vehicle and motor vehicle with a battery

Abstract

Battery (10) for a motor vehicle (12) that is at least partially electrically powered, comprising a battery cell (14) clamped between two end plates (16), a base plate (18) having a top (20) on one side facing the battery cell (14) and a bottom (22) on one side facing away from the battery cell (14), wherein a fastening opening (24) extends through the base plate (18) between the top (20) and the bottom (22), a fastening means (28) which extends at least partially through the fastening opening (24) from the bottom (22) and engages in a receiving opening (30) formed in the end plate (16) to fasten the base plate (18) to at least one of the two end plates (16),a sleeve (26) arranged at least partially in the fastening opening (24) for guiding the fastening element (28) and for transmitting a clamping force exerted via the fastening element (28) into the base plate (18), wherein the sleeve (26) has a higher material strength than the base plate (18).

Description

The invention relates to a battery for a motor vehicle that is at least partially electrically powered, wherein the battery comprises at least one battery cell arranged between two end plates and clamped between them. A base plate is connected to the end plates in a simple manner via a fastening means. The invention further relates to a motor vehicle with the battery according to the invention. Batteries for motor vehicles are generally known. For example, WO 2012 066 875 A1 shows a battery for a motor vehicle in which a plurality of battery cells are arranged between two end plates. The battery cells are covered by upper and lower plates, respectively, which are fastened by bolts. The bolts pass through an opening in the upper and lower plates and engage in the respective end plates. The upper and lower plates are formed as deep-drawn metal parts. Because the upper and lower plates are made of the same metal, such batteries can have a higher weight. JP 2002 367 651 A describes a housing for fuel cells, wherein the housing has a seat plate in the area of ​​a mounting opening, which is fastened to the inside of the housing via a bolt or screw connection. A screw seat is arranged in the seat plate. A screw passes through the screw seat and engages in an end plate of the fuel cell pack. JP 2017 142 942 A describes an energy storage package in which cells are clamped between two end plates. Each end plate has a flange, and screws are passed through the flange to attach the cells to a wall. DE 11 2010 004 703 T5 describes a bucket excavator. The document shows storage battery cells arranged between pressure plates and tensioned by tie rods. Wall plates are arranged on the pressure plates and fastened by screws engaging in the pressure plates. One object of the invention is to provide a battery for a motor vehicle that is at least partially electrically powered, which can be assembled in a simple manner and can have a reduced weight. The problem is solved by the subject matter of the independent patent claim. Preferred embodiments of the invention are the subject matter of the dependent patent claims, whereby each feature, individually or in combination, can represent an aspect of the invention, unless the description explicitly states otherwise. According to the invention, a battery for an at least partially electrically powered motor vehicle is provided, comprising a battery cell clamped between two end plates, a base plate having a top on one side facing the battery cell and a bottom on one side facing away from the battery cell, wherein a fastening opening extends through the base plate between the top and the bottom, a fastening means which is guided at least partially through the fastening opening from the bottom and engages in a receiving opening formed in the end plate in order to fasten the base plate to at least one of the two end plates, a sleeve arranged in the fastening opening for guiding the fastening means and for transmitting a clamping force exerted via the fastening means into the base plate, wherein the sleeve has a higher material strength than the base plate. In other words, one aspect of the present invention is the provision of a battery for a motor vehicle that is at least partially electrically powered. The battery is preferably electrically connected to an electric machine located in the powertrain of the motor vehicle. The battery can therefore supply electrical energy, preferably current, to the electric machine and / or store electrical energy generated by the electric machine. The battery comprises at least one battery cell. It is conceivable that a plurality of battery cells are provided, preferably connected in series or parallel and arranged side by side or one behind the other. If a plurality of battery cells are provided, they form a battery cell module. The battery cell is arranged between two spaced-apart end plates. The end plates are preferably connected to each other via at least one tie rod or tension plate in order to tension the battery cell arranged between the end plates. In other words, a preload force is applied to the battery cell via the tie rod and the end plates. In this way, bulging of the battery cells can preferably be prevented. The battery also includes a base plate with a top and a bottom. The top faces the at least one battery cell. The bottom is formed on the side of the base plate facing away from the battery cell. A mounting opening, preferably with a closed edge, extends through the base plate between the top and bottom. A bore is particularly preferred as the mounting opening. Furthermore, a fastening element is provided which, starting from the underside, is guided at least partially through the fastening opening and engages in a receiving opening formed in the end plate in order to fasten the base plate to at least one of the two end plates. In this way, the base plate can ultimately be positively connected to and / or joined to the end plate via the fastening element. Furthermore, a sleeve is arranged at least partially within the fastening opening to guide the fastener and / or to transfer a preload force applied via the fastener into the base plate. In other words, the fastener is guided at least partially and / or section by section through the sleeve. The sleeve has a higher material strength than the base plate. Therefore, the base plate can be made of a material with a lower material strength than the sleeve. This allows, for example, a reduction in the weight of the base plate. In an advantageous embodiment of the invention, the sleeve is made of metal. A clamping force exerted by the fastening element can advantageously be transferred to the base plate via a metallic sleeve. The fastening element is preferably a bolt and / or a screw. A screw can be easily guided at least partially through the fastening opening and / or the sleeve and engage at least partially in the receiving opening to be positively and / or force-fitted to it. For this purpose, the screw is provided with an external thread and a corresponding internal thread is formed in the receiving opening. It is particularly advantageous if the sleeve and the fastener are made of the same material and / or at least partially consist of the same material. This prevents contact corrosion between the fastener and the sleeve. In a preferred embodiment of the invention, the base plate is made of a plastic, in particular a thermoplastic or a thermosetting plastic. Plastics allow for the production of particularly lightweight components, thus reducing the battery's weight. The thermoplastic is most preferably a semi-crystalline thermoplastic, especially a polybutylene terephthalate (PBT) with a glass fiber content. The glass fiber content of the thermoplastic is preferably between 10% and 40% by mass, and more preferably between 20% and 30%. The limits of these values ​​are included. Advantageously, the plastic is a polybutylene terephthalate with a glass fiber content of 30% (PBT GF30). A semi-crystalline thermoplastic with a glass fiber content exhibits very high stiffness. Furthermore, its dimensional stability is increased.Furthermore, the plastic is readily weldable and exhibits increased resistance to a wide range of solvents. Thermosetting plastics have the advantage of maintaining their shape even under higher temperatures. It is also conceivable that glass fibers, preferably in the aforementioned mass percentage, are added to the thermosetting plastic. In principle, the sleeve can be arranged and / or designed in the mounting opening to guide the fastener and enable the transmission of a preload force exerted by the fastener into the base plate. An advantageous embodiment of the invention is that the sleeve is bonded to the base plate by a material-fit and / or form-fit connection. In this way, the sleeve and the base plate are permanently connected. This simplifies the battery manufacturing process, as the base plate and sleeve form a single unit, eliminating the need to consider the sleeve when inserting the fastener through the mounting opening. A material-bonded connection can be, for example, an adhesive bond. In other words, the sleeve can be at least partially glued into the mounting opening using an adhesive. This adhesive can preferably be a one-component or multi-component adhesive. However, a material-bonded connection can also include the molding of the base plate onto the sleeve. Thus, it can be designed so that the sleeve is already positioned in the base plate's injection mold during the injection molding process in such a way that the base plate is molded onto the sleeve during the injection molding process. A positive-locking connection of the sleeve to the mounting opening can be understood, for example, as a situation where the outer diameter of the sleeve is at least partially larger than the inner diameter of the mounting opening, so that the sleeve at least partially cuts into the mounting opening and is thus positively connected to the base plate. The sleeve is therefore, at least partially, press-fitted within the mounting opening. An advantageous embodiment of the invention lies in the fact that the sleeve has a first outer diameter and a second outer diameter that is larger than the first. In other words, the sleeve has a collar. The collar is preferably located on the underside of the base plate. The section of the sleeve with the first outer diameter engages in the mounting opening and faces the battery cell. When the mounting element is guided through the sleeve with the collar, force can be transmitted to the base plate via the collar, thus increasing the contact pressure of the base plate against the end plate. This also results in a better seal between the base plate and the end plate. According to a preferred embodiment of the invention, the underside of the base plate has stiffening webs and / or stiffening ribs. The stiffening webs and / or stiffening ribs are preferably arranged in a triangular, rectangular, honeycomb, and / or hexagonal configuration relative to one another. Thus, the design of the stiffening webs or stiffening ribs increases the strength and / or stiffness of the base plate and also reduces its weight. A preferred embodiment of the invention provides that a recess and / or a depression is formed on the upper surface of the base plate, and a cooling element is arranged on the upper surface, the cooling element being at least partially positioned in the depression of the base plate. The cooling element is preferably designed as a cooling plate. The cooling plate is preferably configured to guide a cooling medium, in particular a cooling fluid. Meandering cooling loops are preferably formed in the cooling element. By arranging the cooling element in the recess or depression of the base plate, the installation space in the battery can be reduced. In this context, an advantageous further development of the invention lies in the fact that a thermally conductive intermediate layer is arranged at least partially on one side of the cooling element facing the battery cell. In this way, increased thermal coupling between the battery cell and the cooling element can be achieved via the thermally conductive intermediate layer, which can also be referred to as a thermal interface, so that effective and / or increased cooling of the battery cell via the cooling element can be achieved. In this context, it is further stipulated that the thermally conductive intermediate layer is made of a resin, an elastomer, or a silicone. In other words, the thermal intermediate layer exhibits flexible properties, enabling a preferably complete, air-free, and thermally sealed connection of the cooling channel to the battery cell via the thermally conductive intermediate layer. This allows the cooling effect to be increased. According to a preferred embodiment of the invention, a first sealing element is formed between the top surface of the base plate and the cooling element in the area of ​​the mounting opening. The first sealing element can preferably be arranged in a circumferential groove and / or fold formed in the mounting opening. Thus, the first sealing element provides a seal in the area of ​​the mounting opening against the outside environment. A preferred embodiment of the invention consists in a second sealing element being formed between the head of the fastening element and the sleeve. The second sealing element can preferably be arranged in a circumferential groove on an end face of the sleeve facing the head of the fastening element and / or be formed on an end face of the head of the fastening element facing the sleeve. This allows the sealing effect of the battery to be increased in the area of ​​the connection point between the base plate and the end plate. The invention also relates to a motor vehicle with the battery according to the invention. Further features and advantages of the present invention will become apparent from the dependent claims and the following exemplary embodiment. The exemplary embodiment is not intended to be limiting, but rather to be understood as illustrative. It is meant to enable a person skilled in the art to carry out the invention. The applicant reserves the right to make one or more of the features disclosed in the exemplary embodiment the subject of patent claims or to include such features in existing patent claims. The exemplary embodiment is explained in more detail with reference to a drawing. In this work: Fig. 1 shows a three-dimensional view of a battery according to a preferred embodiment of the invention; Fig. 2 shows a longitudinal section through the battery according to a preferred embodiment of the invention; Fig. 3 shows a motor vehicle with the battery. Figure 1 shows a three-dimensional view of a battery 10. Figure 2 shows a longitudinal section through the battery 10. Reference is made to Figures 1 and 2 simultaneously below. The battery 10 is designed and / or intended for use in a motor vehicle 12 that is at least partially electrically powered. A motor vehicle 12 that is at least partially electrically powered can be one that has an internal combustion engine and an electric motor for propelling the motor vehicle 12. It is also conceivable that the motor vehicle 12 is propelled exclusively by an electric motor. The battery 10 is preferably electrically connected to an electric machine that is arranged in the drivetrain of the motor vehicle 12. It can thus supply energy in the form of current to the electric machine for propelling the motor vehicle 12, or store electrical energy generated by the electric machine.The battery 10 comprises a plurality of battery cells 14 arranged in series. Alternatively, the battery 10 may also comprise a plurality of battery cells 14 connected partially in parallel. The plurality of battery cells 14 form a battery cell module. The battery cells 14 are arranged and clamped between two spaced-apart end plates 16. In this way, the battery cells 14 are firmly seated between the two end plates 16. Furthermore, the battery 10 is provided with a base plate 18. The base plate 18 has a top surface 20 on one side facing the battery cells 14. On the other side, the base plate 18 has a bottom surface 22. A mounting opening 24 extends through the base plate 18 between the top surface 20 and the bottom surface 22. A sleeve 26 is arranged in the mounting opening 24.A fastening element 28 extends from the underside 22, at least partially, through the fastening opening 24 and the sleeve 26, and engages in a receiving opening 30, which is arranged or formed in the end plate 16. In this way, the base plate 18 can be easily screwed to the end plates 16 via the fastening element 28, which is preferably designed as a screw, in order to delimit or enclose the battery cells 14 from their underside. The sleeve 26 has a higher material strength than the end plate 18. This allows a preload force or clamping force exerted via the fastening element 28 to be effectively transferred through the sleeve 26 into the base plate 18, resulting in increased contact pressure of the base plate 18 against the end plates 16. The base plate 18 can therefore be made of a lighter and less expensive material, thus reducing the cost and weight of the battery 10. In the exemplary embodiment, the sleeve 26 is made of a metal. The metal can, for example, be stainless steel. It is also conceivable that the sleeve is made of aluminum. The sleeve 26 has a first outer diameter and a second outer diameter that is larger than the first. A bore passing through the sleeve 26 has a uniform diameter along its entire length. The sleeve 26 thus has a kind of outer collar or flange. This flange allows the sleeve to rest, at least partially, on the underside 22. The section of the sleeve 26 with the first outer diameter is therefore located on the side facing the battery cells 14. A head 32 of the fastening element 28 can transmit a force into the sleeve 26 and from the collar into the base plate 18 via the collar or flange of the sleeve 26. The base plate 18 is made of a semi-crystalline thermoplastic with a glass fiber content of 30%. This thermoplastic is polybutylene terephthalate (PBT). Due to the choice of material, the base plate 18 exhibits high rigidity. It also has increased dimensional stability and is resistant to a wide range of solvents. Furthermore, plastics can be lightweight, thus reducing the weight of the battery 10. In addition, plastics are inexpensive to manufacture. Stiffening webs 34 are arranged on the underside 22 of the base plate 18. The stiffening webs 34 are predominantly square or rectangular, although triangular, honeycomb, or hexagonal arrangements and / or designs are also conceivable. The stiffening webs 34 can also be referred to as stiffening ribs. The stiffening webs 34 increase the rigidity of the base plate 18. The sleeve 26 is bonded to the base plate 18 by a material bond. In the present embodiment, the base plate 18 is injection-molded and / or cast onto the sleeve 26. In other words, the sleeve 26 is placed into an injection mold for the base plate 18, and subsequently, the injection molding material is introduced into the mold, thereby bonding the material to the sleeve 26. In this way, the sleeve 26 is bonded to the base plate 18 by a material bond. Consequently, the sleeve 26 is captive and attached to the base plate 18. Therefore, when mounting the base plate 18 to the end plates 16, it is not necessary to ensure that the sleeve 26 does not fall out of the mounting opening 24. This allows the assembly and manufacturing process of the battery 10 to be accelerated and simplified, thereby reducing the manufacturing costs of the battery 10. The upper surface 20 of the base plate 18 is recessed, at least in part. A cooling element 36 is arranged on the upper surface 20, the cooling element 36 engaging or being arranged at least in part within the recessed portion of the base plate 18. Because part of the cooling element 36 is arranged within the recess of the base plate 18, the dimensions of the battery 10 can be reduced. In this way, a compact battery 10 can be provided for installation in a motor vehicle 12. On the upper side of the cooling element 36, i.e., the side facing the battery cells 14, a thermally conductive intermediate layer (not shown) is arranged. This thermally conductive intermediate layer allows for an airtight connection between the cooling element 36 and the battery cells 14, thus increasing the cooling effect of the cooling element 36 on the battery cells 14. In this example, the thermally conductive intermediate layer is made of silicone. A first sealing element 38 is arranged around the sleeve 26 on the upper surface 20 of the base plate 18, so that the upper surface 20 forms a seal against the cooling element 36 via the first sealing element 38. Furthermore, a second sealing element 40 is arranged between the head 32 of the fastening element 28 and the sleeve 26. In this way, the battery cells 14 can preferably be sealed from the outside world via the first sealing element 38 and the second sealing element 40. Figure 3 shows a motor vehicle 12 with the battery 10 according to the invention. In the present example, the motor vehicle 12 is at least partially electrically powered. The battery 10 is located in the drive train of the motor vehicle 12 and is electrically connected to an electric motor for powering the motor vehicle 12.

Claims

Battery (10) for a motor vehicle (12) that is at least partially electrically powered, comprising a battery cell (14) clamped between two end plates (16), a base plate (18) having a top (20) on one side facing the battery cell (14) and a bottom (22) on one side facing away from the battery cell (14), wherein a fastening opening (24) extends through the base plate (18) between the top (20) and the bottom (22), a fastening means (28) which extends at least partially through the fastening opening (24) from the bottom (22) and engages in a receiving opening (30) formed in the end plate (16) to fasten the base plate (18) to at least one of the two end plates (16),a sleeve (26) arranged at least partially in the fastening opening (24) for guiding the fastening element (28) and for transmitting a clamping force exerted via the fastening element (28) into the base plate (18), wherein the sleeve (26) has a higher material strength than the base plate (18). Battery according to claim 1, characterized in that the sleeve (26) is made of a metal. Battery according to one of the preceding claims, characterized in that the base plate (18) is made of a plastic. Battery according to one of the preceding claims, characterized in that the sleeve (26) is bonded to the base plate (18) in a material-bonded and / or form-bonded manner. Battery according to one of the preceding claims, characterized in that the sleeve (26) has a first outer diameter and a second outer diameter larger than the first outer diameter. Battery according to one of the preceding claims, characterized in that the underside (22) of the base plate (18) has stiffening webs (34) and / or stiffening ribs. Battery according to one of the preceding claims, characterized in that a recess and / or a depression is formed on the top (20) of the base plate, and a cooling element (36) is arranged on the top (20) which is arranged at least partially in the depression of the base plate (18). Battery according to claim 7, characterized in that a thermally conductive intermediate layer is arranged at least partially on one side of the cooling element (36) facing the battery cell (14). Battery according to claim 8, characterized in that the thermally conductive intermediate layer is formed from a resin, an elastomer or a silicone. Battery according to one of claims 7 to 8, characterized in that a first sealing element (38) is formed between the top (20) of the base plate (18) and the cooling element (36) in the area of ​​the mounting opening (24). Battery according to one of the preceding claims, characterized in that a second sealing element (40) is formed between a head (32) of the fastening means (28) and the sleeve (26). Motor vehicle (12) with a battery (10) according to one of the preceding claims.

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