Battery for motor vehicle as well as motor vehicle and manufacturing process therefor

Abstract

Battery (14) for a motor vehicle (10) that is at least partially electrically powered, comprising - a battery pack (16) with several battery cells (22), each of the battery cells (22) having two base surfaces (24) which are connected to each other via a lateral surface (26) of the respective battery cell (22), - a battery housing (18) with a slot opening (20) for receiving the battery pack (16), - a frame (32) enclosing the battery pack (16), which is designed as a hollow profile with a closed cross-section, wherein the frame (32) at least partially covers each of the battery cells (22) on the lateral surface (26) of the respective battery cell (22), and - a pretensioning device (36) with a pretensioning unit (38a) designed to generate a pretensioning force (F1) on the battery pack (16) on a first side (34a) of the frame (32).

Description

[0001] The present invention relates to a battery for an at least partially electrically driven motor vehicle. Furthermore, the present invention relates to a corresponding motor vehicle and a manufacturing method for such a battery.

[0002] A battery within the meaning of the invention comprises at least one and in particular several electrically conductively interconnected battery cells. Such a battery cell can be designed, for example, as a prismatic cell, a pouch cell, or a round cell. The battery is preferably configured as a so-called high-voltage battery, which is designed to provide an electrical voltage in the range of more than 60 volts, in particular in the range of several hundred volts. Such a high-voltage battery can be arranged in a motor vehicle, where it can supply an electrical consumer, in particular a drive motor, with electrical energy.

[0003] To ensure that such a battery cell has a long service life when used as intended and can be operated particularly safely in the event of damage, such as an internal short circuit, various approaches are known in the art. For example, a preload force can be applied to the battery cell or to a battery module comprising several battery cells to compensate for the service life-shortening expansion of the battery cell(s). Furthermore, thermal insulation can be provided to prevent or delay thermal propagation of the battery cell(s).

[0004] US 2019 / 0312323 A1 describes a thermal management system comprising a cell bank with multiple batteries and a cell frame for aligning the batteries with welding straps. A spring can be arranged between an edge of the cell bank and a battery of a battery stack to compress the batteries and a thermal interface material between the batteries, thereby increasing contact and heat transfer between the batteries.

[0005] US 2019 / 0363392 A1 discloses a battery module comprising a battery cell stack containing a plurality of battery cells and a housing surrounding the battery cell stack. Furthermore, the battery module comprises an elastic element, each connected to two inner sides of the housing, designed to apply uniform pressure to the battery cells when swelling occurs.

[0006] Furthermore, DE 29 25 248 A1 discloses a method for measuring the state of charge of rechargeable galvanic cells with swelling electrodes and alkaline electrolytes. Individual cells are arranged adjacent to one another between at least one fixed plate and a movable plate, with the movable plate being connected to a spring arrangement (e.g., consisting of several disc springs) via which a predetermined preload can be set.

[0007] In addition, further battery systems, battery arrangements and battery management systems are known from the documents US 2019 / 0 379 030 A1, US 2012 / 0 003 522 A1 and US 2005 / 0 260 488 A1.

[0008] In known pre-stressed high-voltage batteries, each cell module comprises several battery cells arranged within a module housing, which can increase the weight of the battery. Furthermore, a complex design and construction of each of the cell modules is required, for example, to absorb a force caused by the expansion of the battery cells (so-called swelling force) and to prevent thermal runaway of the battery cells in the event of damage to at least one of the battery cells.

[0009] Against this background, the object of the present invention is to provide an improved concept for a battery of the type described above, which is particularly lightweight and easy to manufacture. Furthermore, the object of the present invention is to provide a motor vehicle with such a battery and a corresponding manufacturing method.

[0010] According to the invention, this object is achieved by the subject matter of the independent patent claims. Advantageous developments of the invention are described by the dependent patent claims, the following description, and the figures.

[0011] The improved concept is based on the idea of ​​dispensing with the arrangement of the battery cells in individual cell modules and arranging the battery cells in a frame enclosing the battery pack in order to apply a preload force to the battery by means of a preload device.

[0012] The improved concept provides a battery for an at least partially electrically powered motor vehicle. The battery comprises a battery pack with a plurality of battery cells, a battery housing for accommodating the battery pack, a frame enclosing the battery pack, and a pretensioning device with a pretensioning unit for applying a pretensioning force to the battery pack. A battery within the meaning of the improved concept is preferably understood to be a battery that utilizes so-called cell-to-pack (CTP) technology. This eliminates the need to arrange the battery cells in individual cell modules, thereby particularly advantageously increasing the packing density of the battery cells and the energy density of the battery pack.

[0013] The battery pack, which can also be referred to as a cell package, comprises a plurality of battery cells. In particular, the battery cells forming the battery pack can be battery cells of the type mentioned above. The battery pack can have at least one battery cell, in particular between two and eight battery cells. Each of the battery cells of the battery pack has two base surfaces which are connected to one another via a lateral surface of the respective battery cells. Thus, each of the battery cells is delimited on the outside by the two base surfaces and the lateral surface, which together form a surface of each of the battery cells. Thus, the two base surfaces and the lateral surface can also be understood as boundary surfaces of the battery. The two base surfaces, which can also be referred to as so-called end surfaces, can be, for example, a bottom surface and a top surface opposite the bottom surface.In this case, each of the battery cells can rest, in particular, on the base surface, for example, on a wall of the battery housing, while an electrical connection can be arranged on the top surface. The outer surface can be defined by a respective circumference of each of the base surfaces and a height of the battery. In this context, the height can indicate a normal distance between the two base surfaces. The respective shape of the base surfaces and the outer surfaces can be defined, in particular, by a design of the battery cell (e.g., prismatic cell, pouch cell, or round cell).

[0014] The battery further comprises the battery housing, which has an insertion opening for receiving the battery pack. The battery housing is a casing for the battery, i.e. a particularly solid shell which surrounds the battery pack. In this case, the battery housing can in particular advantageously protect the battery pack from the environment of the battery and vice versa. For example, the battery housing can prevent liquid from entering the battery and alternatively or additionally prevent or limit the escape of gases escaping from one of the battery cells. In particular, the battery housing contains or is made of a metallic material (e.g. aluminium or steel). The insertion opening is understood to be a recess within the battery housing in which the battery pack is arranged, i.e. positioned, after the battery has been manufactured as intended.In particular, the insertion opening can be a container closed on at least three sides, especially four or five sides, with a square inner shape, which can be predetermined depending on the design of the battery cells. In particular, the battery housing can have several insertion openings arranged parallel to one another, for example, between two and six.

[0015] Furthermore, the battery pack is enclosed by the frame, which is designed as a hollow profile with a closed cross-section. The frame can therefore surround the battery pack in a tubular shape. The hollow profile forms a hollow body whose cross-section is normal to a longitudinal direction of the hollow profile and parallel to the base areas of each battery cell, for example circular, rectangular or oval at least in sections. By means of the frame, for example, the battery cells can be arranged next to one another in such a way that the battery pack is present as a single component and is particularly easy to handle during assembly (e.g. when arranged in the battery housing). In particular, the frame contains or is made of a plastic. When the frame is arranged on the battery pack, the frame at least partially covers each of the battery cells on the outer surface of the respective battery cell.Thus, the frame rests at least partially against the outer surface, particularly at the end face, of the respective battery cell, so that the frame is arranged on each of the battery cells in this area. In particular, the two base surfaces can be unobstructed by the frame, since the hollow profile is open on both sides. Compared to a module housing, the frame can thus partially cover the battery cells forming the battery pack. The advantage is that a module housing is dispensed with, thus reducing the manufacturing and material costs of the battery.

[0016] The battery also comprises the pretensioning device with the pretensioning unit. The pretensioning unit of the pretensioning device is designed to generate a pretensioning force on the battery pack on a first side of the frame. The pretensioning force can be between 1 and 10 kN, in particular between 2 and 5 kiloNewtons. In particular, a line of action of the pretensioning force can run normal to the first side of the frame and the pretensioning force can act from the environment towards the battery pack. The pretensioning force is, for example, the force required to compensate for operational swelling of at least one of the battery cells in order to advantageously increase the service life of at least one of the battery cells and therefore of the battery pack. The pretensioning unit is thus designed to apply the pretensioning force to the battery pack at the latest after assembly of the battery.

[0017] Advantageously, the battery according to the improved concept is particularly easy to design and manufacture. Due to the smaller number of components that make up the battery compared to a modular design, the battery according to the improved concept is more cost-effective, has a lower weight, and requires less installation space.

[0018] An advantageous embodiment provides that the pretensioning device has a further pretensioning unit which is designed to generate a further pretensioning force on the battery pack on a second side of the frame opposite the first side, so that the pretensioning force of the pretensioning unit and the further pretensioning force of the further pretensioning unit act in opposite directions to one another. This results in the advantage that the battery pack is pretensioned particularly evenly. The pretensioning device comprises two pretensioning devices, i.e. the pretensioning device and the further pretensioning device. By means of the two pretensioning devices, a respective pretensioning force can be applied to the battery pack on a respective side of the frame assigned to the respective pretensioning device, i.e. the first pretensioning device applies the pretensioning force on the first side of the frame and the further pretensioning device applies the further pretensioning force on the second side.The first side and the second side are two opposite sides of the frame. In particular, the first side and the second side can be arranged parallel to each other. Furthermore, the lines of action of the two preload forces, i.e., the preload force and the second preload force, can be parallel to each other, but oriented opposite to each other. This can further increase the battery's service life.

[0019] A further advantageous embodiment provides that the prestressing device has a plate element which rests with an upper plate side over its entire surface on the first side of the frame and which is arranged with a lower plate side on at least one prestressed spring element. A plate element is to be understood as a plane and flat component which is delimited by the upper plate side and the lower plate side. The upper plate side and the lower plate side are arranged opposite one another and in particular parallel to one another. A normal distance between the upper plate side and the lower plate side is in particular the same over the entire plate element, i.e. the plate element is the same thickness everywhere. The plate element is preferably dimensionally stable, i.e. a shape of the plate element is designed to be resistant (for example to compressive stress).For this purpose, the plate element can be made from a metal or a plastic, for example. This has the advantage that the prestressing force of the prestressing device acts on the frame particularly evenly across the top side of the plate. Furthermore, the prestressing force is defined, i.e. predetermined, by the at least one spring element which is arranged on the underside of the plate element. The at least one spring element is a component which can be elastically and / or plastically deformed under the action of force. In particular, the spring element can be made from or contain a metal. In particular, a plurality of spring elements are provided which can be evenly distributed over the underside of the plate in order to prevent the plate element from tipping or jamming when the prestressing force is applied.In addition, the at least one spring element can have a guide element, for example a guide rail, in particular when there is a single spring element, in order to counteract tilting or canting of the plate element. The at least one spring element is preloaded, which means that it is designed to release the preload force directly outwards, in particular in the direction of the battery pack. The at least one spring element has a defined spring constant and, alternatively or additionally, a defined spring characteristic curve which specifies the preload force. The spring characteristic curve describes a relationship between a force (or a torque) acting on the at least one spring element and a deflection of the at least one spring element caused thereby, i.e. its absolute extension or twisting. The spring constant (spring stiffness) is a gradient of the spring characteristic curve in a spring diagram.Depending on the design of the at least one spring element, the spring characteristic can be linear, progressive, degressive, or a combination of these. This offers the advantage that a spring characteristic of the at least one spring element, which is determined by a spring characteristic and / or the spring constant, allows the preload force to be adjusted particularly flexibly and precisely over the service life of the battery pack.

[0020] A further advantageous embodiment provides that the pretensioning device is connected to a further plate element via the at least one spring element. The further plate element is preferably designed analogously to the plate element already described. The at least one spring element is thus arranged between the plate element and the further plate element. As a result, the pretensioning device is advantageously designed to generate the pretensioning force by means of the plate element and a pretensioning force acting opposite to the pretensioning force by means of the further plate element. This may be necessary, for example, if the battery has a further battery pack in addition to the battery pack and the pretensioning device is arranged between the battery pack and the further battery pack.As a result, such a pretensioning device can particularly advantageously apply the pretensioning force to the battery pack via the plate element and the opposing pretensioning force to the further battery pack via the further plate element. Alternatively or additionally, the pretensioning device is arranged directly on the battery housing. The pretensioning device can be part of the battery housing or integrated into the battery housing. In particular, the pretensioning device can be arranged on an end face of the insertion opening. This has the advantage that the installation space required for the pretensioning device can be kept to a minimum. Alternatively or additionally, the at least one spring element contains a helical spring and / or a flat spring with a wave-shaped cross-section. The helical spring can in particular be a metallic wire wound, i.e. bound, in a helical shape.For example, the coil spring is designed as a torsionally loaded helical compression spring. The coil spring is designed to introduce the preload force into the coil spring via at least one end turn of the coil spring when the coil spring is compressed, to store the preload force and to partially transmit it to the battery pack via the frame when the coil spring is released. The flat spring has a wave-shaped cross-section, so that the flat spring can correspond to the shape of a corrugated sheet. The flat spring can, for example, be punched and formed from spring strip steel. Due to the wave-shaped cross-section, the flat spring is curved, i.e. it can be composed of straight and circular arc parts. There is no need to attach the flat spring to the plate element, which would weaken the plate element as a result.By designing the at least one spring element as a helical spring and / or as a flat spring, the pretensioning device can be designed to be particularly compact.

[0021] A further advantageous embodiment provides that the frame has two further sides, each perpendicular to the first side, which are each arranged between the battery pack and a wall of the battery housing that delimits the insertion opening. The frame can thus simulate the shape of a U-profile, with the first side forming a web of the U-profile and the two further sides perpendicular to the first side forming two parallel flanges of the U-profile. The battery pack is positioned on the wall of the battery housing that delimits the insertion opening via the two further sides of the frame. In particular, the wall can encompass two long sides of the insertion opening. This has the advantage that the battery pack can be connected to the battery housing via the two further sides, either directly or via an air gap, and the battery can be designed to be particularly compact.

[0022] A further advantageous embodiment provides that the battery pack has a separating element. The separating element is positioned between two adjacent battery cells and designed to thermally insulate the two adjacent battery cells from one another. The two adjacent battery cells are battery cells arranged next to one another. Alternatively, the separating element is positioned between one end of the battery cells and the frame and designed to thermally insulate the end of the battery cells and the frame from one another. The end of the battery cells is only adjacent to another of the battery cells. In this context, the battery pack can in particular have two end battery cells. The separating element arranged between two of the battery cells or between one of the battery cells and the frame is designed to provide a thermal insulation function.This insulating function can be provided, in particular, by a material forming the separating element, which has a low thermal conductivity, for example, less than 0.5 watts per meter and Kelvin. For example, the separating element is made of a plastic. Advantageously, the battery has multiple separating elements, so that each of the battery cells is arranged at least on one side, in particular on both sides, on a respective one of the separating elements. This offers the advantage that, if at least one of the battery cells heats up or overheats, heat transfer to the battery cells differing from it can be prevented, limited, or delayed.

[0023] A further advantageous embodiment provides that the separating element is present as a separate component or is integrated into the frame.

[0024] This makes the separating element, designed as a separate component, particularly easy to replace. This can be advantageous, for example, if a requirement for the separating element's insulating function changes and a currently installed separating element needs to be replaced with one that meets the requirement. Alternatively, the separating element is integrated into the frame, i.e., the separating element is part of the frame. This reduces assembly effort, as it eliminates the need to insert the separating element, for example, between the end of the battery cells and the frame.

[0025] A further advantageous embodiment provides that the outer surface of each battery cell has a rectangular cross-section with two long sides and two end faces that are shorter than the long sides. Two adjacent battery cells are arranged next to one another along their long sides. In particular, each battery cell is designed as a prismatic cell. The rectangular cross-section of the outer surface is defined by the rectangular base surfaces, which run parallel to the rectangular cross-section of the outer surface. The outer surface can in particular comprise four rectangular surfaces, two of the rectangular surfaces being defined by the long sides of the outer surface and the height of each battery cell, and the other two rectangular surfaces being defined by the end faces of the outer surface and the height of each battery.Within the battery pack, each battery cell is positioned with at least one of its long sides against another battery cell. Since the long sides are longer than the end faces, and thus also the two rectangular surfaces formed by them, the contact area between two adjacent battery cells is advantageously particularly large.

[0026] According to the improved concept, a motor vehicle with a battery is also provided, wherein the battery is designed to electrically supply a drive motor of the motor vehicle. The battery is preferably an advantageous embodiment of the battery according to the improved concept. The motor vehicle is preferably designed as a motor vehicle, in particular as a passenger car or a truck, or as a passenger bus or a motorcycle. The drive motor of the motor vehicle can be designed, for example, as an electric drive or a hybrid drive.

[0027] The invention also includes further developments of the motor vehicle according to the invention that have features already described in connection with the further developments of the battery according to the invention, and vice versa. For this reason, the corresponding further developments of the motor vehicle according to the invention are not described again here.

[0028] According to the improved concept, a method for producing a battery is also provided. The method for producing the battery can also be referred to as a manufacturing method. The battery is preferably an advantageous embodiment of the battery according to the improved concept. The battery comprises a battery pack with a plurality of battery cells, each of the battery cells having two base surfaces connected via a lateral surface. The battery further comprises a battery housing with an insertion opening for receiving the battery pack and a pretensioning device with a pretensioning unit.

[0029] In a first step of the process, the battery pack is enclosed by a frame formed as a hollow profile with a closed cross-section, so that the frame at least partially covers the outer surface of each battery cell. The two base surfaces, however, remain unobstructed.

[0030] In a second step of the method, an assembly state of the pretensioning device is set, wherein before being arranged within the battery housing, the pretensioning unit is pretensioned and fixed in such a way that an outwardly directed pretensioning force is prevented. When setting the assembly state of the pretensioning device, the pretensioning force is first introduced into the pretensioning unit. Fixing the pretensioning device, which can in particular be done mechanically, prevents the pretensioning force from being transmitted outwards, thereby preventing a reduction in the pretensioning force and allowing it to be stored temporarily, i.e. until the fixation is released, in the pretensioning device. The second step of the method can be carried out before, after or simultaneously with the first step of the method.

[0031] In a third step of the method, the enclosed battery pack and the fixed pretensioning device are arranged in the insertion opening of the battery housing, with the fixed pretensioning unit adjacent to a first side of the frame. The enclosed battery pack and the fixed pretensioning device are thus positioned together within the battery housing in the insertion opening. The fixed pretensioning device and the enclosed battery pack are arranged adjacent to one another via the first side of the frame.

[0032] In a fourth step of the method, an operating state of the pretensioning device arranged in the battery housing is set. The pretensioning unit's fixation is released, so that the pretensioning force is applied to the battery pack on the first side of the frame. By transferring the pretensioning device from the assembled state to the operating state, the pretensioning force stored in the pretensioning unit can act on the battery pack via the first side of the frame. This can particularly advantageously increase the service life of the battery cells forming the battery pack.

[0033] The invention also includes further developments of the method according to the invention that have features already described in connection with the further developments of the battery according to the invention and / or the motor vehicle according to the invention, and vice versa. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0034] The invention also includes combinations of the features of the described embodiments.

[0035] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 is a schematic representation of an exemplary embodiment of a motor vehicle according to the improved concept; and Fig. 2 is a schematic sectional view of an exemplary embodiment of a battery according to the improved concept.

[0036] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0037] In the figures, identical reference numerals designate functionally identical elements. For the sake of clarity, identical and multiple-illustrated elements, particularly in the Fig. 2, incomplete but at least once provided with a corresponding reference symbol.

[0038] The Fig. 1 shows, by way of example, a motor vehicle 10 configured as a passenger car with a drive motor 12 and a battery 14. The battery 14 can be configured as a so-called high-voltage battery to electrically supply the drive motor 12. Thus, the motor vehicle 10 can be at least partially electrically driven, and the drive motor 12 can be configured as an electric drive or a hybrid drive.

[0039] The Fig. 2 shows, by way of example, with reference to the information provided in connection with the Fig. 1 shows a section of the battery 14 in a plan view of the components shown and described. The battery 14 comprises four battery packs 16, a battery housing 18, a respective frame 32 enclosing each battery pack 16, and a pretensioning device 36.

[0040] The battery housing 18 has two insertion openings 20 for receiving the battery packs 16, wherein the two insertion openings 20 are arranged one above the other in the y-direction. In the respective insertion opening 20, the battery packs 16 are positioned in pairs next to one another in the x-direction, i.e., left and right. The battery packs 16 are relatively displaceable in the x-direction and relatively immovable in the y-direction within the insertion openings 20. Each battery pack 16 comprises six battery cells 22 arranged next to one another, wherein each battery cell 22 has two base surfaces 24, which are connected to one another via a lateral surface 26 of the respective battery cell 22. In total, the battery 14 can have, for example, between 150 and 200 battery cells 22. In the Fig. 2, only one of the two base surfaces 24, i.e., a top surface with an electrical connection, is shown visible, while the second of the two base surfaces 24, i.e., a bottom surface, is concealed. In particular, each battery cell 22 can be designed as a prismatic cell, so that the two base surfaces 24 are rectangular, and thus the lateral surface 26 of each battery cell 22 has a rectangular cross-section with two long sides 28 in the y-direction and two end faces 30 in the x-direction that are shorter than the long sides 28. Two adjacent battery cells 22 within the battery pack 16 are arranged adjacent to one another at their long sides 28.

[0041] Each battery pack 16 is enclosed by the frame 32, which is designed as a hollow profile with a closed cross-section, wherein the frame 32 at least partially covers each of the battery cells 22 on the outer surface 26. In particular, each battery cell 22 is covered by the frame 32 on the end faces 30 of the outer surface 26. Additionally, in the case of the end battery cells 22 of each battery pack 16, one of the longitudinal sides 28, which outwardly delimits the battery pack 16, can be covered by the frame 32. The two base surfaces 24 of each of the battery cells 22 are not covered by the frame 32. The frame 32 has a first side 34a, an opposite second side 34b, each in the y-direction, as well as two further sides 34c, 34d. The two further sides 34c, 34d are each perpendicular to the first side 34c and the second side 34b, ie in the x-direction.Thus, the longitudinal sides 28 of each battery cell 22 are parallel to the first side 34a and the second side 34b and the end sides 30 are parallel to the two other sides 34a, 34d.

[0042] Furthermore, the battery 14 has the pretensioning device 36. The pretensioning device 36 comprises a pretensioning unit 38a and a further pretensioning unit 38b. The two battery packs 16 located at the ends of the insertion openings 20, ie the two in the Fig. 2 battery packs 16, shown on the right in the x-direction and shown one above the other in the y-direction, are each arranged with the first side 34a of the frame 32 on the pretensioning unit 38a, each with the second side 34b of the frame 32 on the further pretensioning unit 38b and each with the further sides 34c, 34c of the frame 32 on a wall 40 delimiting the insertion opening 20. The pretensioning unit 38a is designed to apply a pretensioning force F1 to the first side 34a of the frame 32 arranged thereon, which pretensioning force is schematically shown as an arrow running opposite to the x-direction.Analogously, the further pretensioning unit 38b is designed to apply a further pretensioning force F2 to the second side 34b of the frame 32 arranged thereon, which is schematically shown as an arrow running in the x-direction, so that the pretensioning force F1 of the pretensioning unit 38a and the further pretensioning force F2 of the further pretensioning unit 38b act in opposite directions to one another, as for the one shown in the . Fig. 2 in the top right arranged battery pack 16 is shown as an example.

[0043] The pretensioning device 36 has a plate element 42a, which rests with a plate upper side over its entire surface on the first side 34a of the frame 32 and is arranged with a plate underside on a pretensioned spring element 44. The at least one spring element 44 has a defined spring constant and alternatively or additionally a defined spring characteristic curve, which specifies the pretensioning force F1 and the further pretensioning force F2. The pretensioning device 36 is here, as shown in each case on the pretensioning unit 38b, connected to a further plate element 42b via the spring element 44 designed as three helical springs 46a. Alternatively or additionally, the pretensioning device 36 can be arranged directly on the battery housing 18, as shown in each case for the pretensioning unit 38a. In this case, in the Fig. 2 battery packs 16 arranged at the top right are fastened to the battery housing 18 via a flat spring 46b with a wave-shaped cross-section (corrugated sheet) and the plate element 42a of the battery packs 16 arranged at the bottom right three further coil springs 46a.

[0044] Furthermore, the battery 14 comprises a plurality of separating elements 48 for thermal insulation. A respective separating element 48 can be positioned between two adjacent battery cells 22 in order to thermally insulate the two adjacent battery cells 22 from one another. Alternatively or additionally, separating elements 48 can each be arranged between an end of the battery cells 22 and the frame 32 in order to thermally insulate the end of the battery cell 22 and the frame 32 from one another. The separating elements 48 can each be present as a separate component 50 or integrated into the frame 32.

[0045] In a first step S1 of a method for producing the battery 14, the battery pack 16 is enclosed by the frame 32, such that each of the battery cells 22 is at least partially covered by the frame 32 on the outer surface 26 of the respective battery cell 22. In a second step S2 of the method, an assembly state of the pretensioning device 36 is set, wherein, before being arranged within the battery housing 18, the pretensioning unit 38a is pretensioned and fixed in such a way that the outwardly directed pretensioning force F1 is prevented. The second step S2 of the method can be carried out before, after, or simultaneously with the first step S1 of the method. In a third step S3 of the method, the enclosed battery pack 16 and the fixed pretensioning device 36 are arranged in the insertion opening 20 of the battery housing 18, wherein the fixed pretensioning unit 38a adjoins the first side 34a of the frame 32.Alternatively or additionally, the fixed further pretensioning unit 38b can be arranged on the second side 34b of the frame 32, as in connection with the two in the . Fig. 2 battery packs 16 shown on the right. In a fourth step S4 of the method, an operating state of the pretensioning device 36 arranged in the battery housing 18 is set. In this case, a fixation of the pretensioning unit 38a is released, so that the pretensioning force F1 is applied to the battery pack 16 on the first side 34a of the frame 32. If the further pretensioning unit 38a is also present, by releasing its fixation, the further pretensioning force F2 can act on the second side 34b of the frame 32 opposite to the pretensioning force F1 of the pretensioning unit 38a.

[0046] The improved concept is based on the knowledge that the battery 14, which is designed as a high-voltage battery, for the motor vehicle 10 can currently have at least one cell module with a cell packet (battery pack 16). When designing this, it is necessary for the at least one cell module to have both the required bias voltage to withstand or compensate for a swelling force of the cell packet and also thermal propagation protection, the latter being designed to prevent or delay thermal propagation of the cell packet. This can result in great effort in manufacturing the at least one cell module and a high weight of the battery 14 due to increased material requirements (e.g. module housing). Furthermore, due to the increased material requirements and increased manufacturing effort, the battery 14 can be cost-intensive and the design of the at least one cell module with regard toa swelling behavior over the lifetime of the battery 14 can be very complex.

[0047] Thus, the improved concept is based on the idea that the cell pack can be inserted directly into a simple support frame (frame 32) in a housing frame of the battery housing 18. A required preload (preload force F1 and further preload force F1) can be applied via two respective plate elements 42a, 42b via the spring element 44. In this way, the required preload can be adjusted via the spring characteristic curve and swelling of the battery cells 22 can be compensated via the preloaded spring element 44. This results in the advantage that the cell pack is easier to design and manufacture compared to the previously mentioned at least one rigid cell module. The preload force F1 and further preload force F1 can also be adjusted particularly flexibly and precisely over the service life of the battery 14. Furthermore, by eliminating many module components (e.g.Module housing) such a battery 14 can be manufactured particularly cheaply, be lightweight and have a small installation space requirement.

[0048] If rapid aging of the battery cells 22 is advantageous, the prestressing device can also comprise only the prestressing unit 38a, whereby an asymmetry in rigidity that promotes aging can be provided, ie, the battery housing 18 is stiffer than the plate element 40a with the spring element 44. In particular, two prestressing units 38a, 38b are provided to prestress the battery pack 16 and the battery cells 22 contained therein from both sides 34a, 34b with equal prestressing forces F1, F2.

[0049] Overall, the examples show how the battery 14 can be provided with the cell packages (battery packs 16) integrated into the battery frame, wherein the cell packages are prestressed via spring plates (plate elements 42a, 42b with at least one spring element 44).

Claims

[1] Battery (14) for an at least partially electrically driven motor vehicle (10), comprising - a battery pack (16) with a plurality of battery cells (22), each of the battery cells (22) having two base surfaces (24) which are connected to one another via a lateral surface (26) of the respective battery cell (22), - a battery housing (18) with an insertion opening (20) for receiving the battery pack (16), - a frame (32) enclosing the battery pack (16), which frame is designed as a hollow profile with a closed cross-section, wherein the frame (32) at least partially covers each of the battery cells (22) on the lateral surface (26) of the respective battery cell (22), and - a pretensioning device (36) with a pretensioning unit (38a) which is designed to generate a pretensioning force (F1) on the battery pack (16) on a first side (34a) of the frame (32). [2] Battery (14) according to claim 1, wherein the pretensioning device (36) has a further pretensioning unit (38b) which is designed to generate a further pretensioning force (F2) on the battery pack (16) on a second side (34b) of the frame (32) opposite the first side (34a), so that the pretensioning force (F1) of the pretensioning unit (38a) and the further pretensioning force (F2) of the further pretensioning unit (38b) act in opposite directions to one another. [3] Battery (14) according to one of the preceding claims, wherein the prestressing device (36) comprises a plate element (42a) which rests with a plate upper side over its entire surface on the first side (34a) of the frame (32) and is arranged with a plate underside on at least one prestressed spring element (44), wherein the at least one spring element (44) has a defined spring constant and / or a defined spring characteristic curve which specifies the prestressing force (F1). [4] Battery (14) according to claim 3, wherein - the pretensioning device (36) is connected to a further plate element (42a) via the at least one spring element (44) and / or is arranged directly on the battery housing (18) and / or - the at least one spring element (44) contains a helical spring (46a) and / or a flat spring (48b) with a wave-shaped cross-section. [5] Battery (14) according to one of the preceding claims, wherein the frame (32) has two further sides (34c, 34d) which are each perpendicular to the first side (34a) and which are each arranged between the battery pack (16) and a wall (40) of the battery housing (18) which delimits the insertion opening (20). [6] Battery (14) according to one of the preceding claims, wherein the battery pack (16) has a separating element (48) which - is positioned between two adjacent battery cells (22) and is designed to thermally insulate the two adjacent battery cells (22) from each other or - is positioned between an end of the battery cells (22) and the frame (32) and is designed to thermally insulate the end of the battery cells (22) and the frame (32) from each other. [7] Battery (14) according to claim 6, wherein the separating element (22) is present as a separate component (50) or is integrated into the frame (32). [8] Battery (14) according to one of the preceding claims, wherein the lateral surface (26) of each battery cell (22) has a rectangular cross-section with two longitudinal sides (28) and two end faces (30) which are shorter than the longitudinal sides (28), wherein two adjacent battery cells (22) are arranged on one another at their longitudinal sides (28). [9] Motor vehicle (10) with a battery (14) according to one of the preceding claims, wherein the battery (14) is designed to electrically supply a drive motor (12) of the motor vehicle (10). [10] Method for producing a battery (14), wherein the battery (14) has a battery pack (16) with a plurality of battery cells (22), wherein each of the battery cells (22) has two base surfaces (24) connected via a lateral surface (26), wherein the battery (14) further comprises a battery housing (18) with an insertion opening (20) for receiving the battery pack (16) and a pretensioning device (36) with a pretensioning unit (38a), characterized by following steps: (S1) enclosing the battery pack (16) by means of a frame (32) which is designed as a hollow profile with a closed cross-section, so that each of the battery cells (22) is at least partially covered by the frame (32) on the lateral surface (26) of the respective battery cell (22); (S2) Setting an assembly state of the pretensioning device (36), wherein, before being arranged within the battery housing (18), the pretensioning unit (38a) is pretensioned and fixed in such a way that an outwardly directed pretensioning force (F1) is prevented; (S3) arranging the enclosed battery pack (16) and the fixed pretensioning device (36) in the insertion opening (20) of the battery housing (18), wherein the fixed pretensioning unit (38a) is adjacent to a first side (34a) of the frame (32); and (S4) Setting an operating state of the pretensioning device (36) arranged in the battery housing (16), wherein a fixation of the pretensioning unit (38a) is released so that the pretensioning force (F1) is applied to the battery pack (16) on the first side (34a) of the frame (32).

Images