Battery module housing for a battery module, battery module, and electrical energy storage unit

Abstract

The present invention relates to a battery module housing (22) for a battery module (14, 16), at least one battery cell (18) undergoing a volumetric change depending on a cell condition, the battery module housing (22) having at least one module frame (24), the module frame (24) forming at least one first accommodation area (26) for the battery cell (18) and a second accommodation area (28) for a pressure regulator (20), the pressure regulator (20) being configured to regulate the volume of the battery module housing (22) relative to the battery cell (18). The pressure regulator (20) is configured to contact the battery cells (18) and regulate a predetermined value of pressure on the battery cells (18) in response to a volume change, the pressure regulator (20) having at least one tubular and flexible first pressure body (30) and a separate tubular and flexible second pressure body (32), between which a movable intermediate pressure plate (34) is formed in at least partial contact with the first pressure body (30) and the second pressure body (32). The present invention further relates to a battery module (14, 16) and an electric energy storage unit (12).

Description

[Technical Field]

[0001] The present invention relates to a battery module housing for a battery module of an electrical energy store with at least one battery cell according to the preamble of claim 1. Furthermore, the invention relates to a battery module and an electrical energy store. [Background technology]

[0002] Battery module housings, which are designed for electrical energy storage, for example, in automotive applications, are already known from the prior art. At least one battery cell, particularly a plurality of battery cells, can be mounted in the battery module housing, thus forming a frame for the battery cells. The battery cells can be, for example, pouch cells, which can undergo volume changes depending on the cell state, particularly the actual charge state, and depending on the aging of the battery cells. This volume change, also known as cell breathing, is important here. It is important that the volume changes of the battery cells can be compensated for within the battery module housing. Furthermore, for example, with prismatic cells, a certain amount of pressure must be applied to the battery cells, thereby enabling the battery cells to utilize their increased capacity.

[0003] Patent Document 1 discloses a battery including at least one battery cell having a plurality of electrodes stacked in parallel, and a pressure device capable of applying pressure to the electrodes. The frame is closed on all sides. The pressure device and the at least one battery cell are arranged in the frame in the longitudinal direction of the frame such that, when the pressure device applies pressure, a pressure region of the pressure device presses the electrodes in the longitudinal direction, and a support region of the pressure means, facing the pressure region, is supported by a first frame wall of the frame in the longitudinal direction opposite the aforementioned longitudinal direction. [Patent Document 1] DE 10 2018 204 220 A1

[0004] Patent document 2 relates to a clamping device for battery cells, in which a container including a space with a variable volume is formed to contain a fluid, and the container is formed so that one or more battery cells can be clamped. [Patent Document 2] EP 3 189 552 A2

[0005] Patent Document 3 relates to an electric energy storage unit having at least one electrode stack, the electrode stack including multiple layers of electrodes arranged one behind the other in a stacking direction and separators arranged between the electrodes. At least one pressure plate is provided to apply pressure to the electrode stack acting in the stacking direction. At least one actuator is provided to apply a force to the pressure plate. The electrode stack and the pressure plate are arranged in a housing of the electric energy storage unit. The electric energy storage unit has a control device for driving and controlling the at least one actuator. The control device is configured to apply a substantially constant force to the pressure plate using the actuator depending on the respective thicknesses of the at least one electrode stack. [Patent Document 3] DE 10 2019 007 748 A1 Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery module housing, a battery module, and an electrical energy storage unit that can achieve improved operation of the battery cells. [Means for solving the problem]

[0007] This problem is solved by a battery module housing, a battery module and an electrical energy store according to the independent claims. Advantageous embodiments are described in the dependent claims.

[0008] A first independent aspect of the present invention relates to a battery module housing for a battery module of an electrical energy storage unit, comprising at least one battery cell, the at least one battery cell undergoing a volume change depending on a cell state, and at least one module frame, which forms in the battery module housing at least one first accommodating area for the at least one battery cell and a second accommodating area for a pressure regulating device, the pressure regulating device being at least partially in contact with the at least one battery cell when the battery module is assembled and configured to regulate a predetermined value of pressure on the battery cell depending on the volume change.

[0009] Here, the pressure regulating device has at least a first tubular flexible pressure body and a separate second tubular flexible pressure body, and a movable intermediate pressure plate is formed between the first and second pressure bodies and is in at least partial contact with the first and second pressure bodies.

[0010] This allows for a continuous and simple structure of the pressure regulating device, thereby improving the operation of at least one battery cell. In particular, the tubular, flexible pressure body allows for a reliable and evenly distributed pressure to be applied to the at least one battery cell. Thus, slight volume changes within the pressure body can be achieved by the first and second pressure bodies, but a corresponding pressure can still be reliably applied by the at least two pressure bodies. The intermediate pressure plate, in particular, is configured to apply the pressure of the first pressure body to the second pressure body in a uniform and evenly distributed manner, for example, while the second pressure body is in contact with the at least one battery cell via the pressure plate. In particular, in the above-described embodiment, the first pressure body can be supported, for example, on a module frame, thereby allowing a corresponding pressure to be applied to at least one battery cell supported on the opposite side of the module frame.

[0011] By using multiple pressure bodies or multiple pressure bodies, it is possible to achieve large volume compensation for cells with varying volumes in an even more space-saving manner.

[0012] Here, the intermediate pressure plate being movable is understood to mean, in particular, that the position of the intermediate pressure plate can be changed within the module frame in response to a volume change or pressure adjustment, in particular that the intermediate pressure plate can move within the module frame.

[0013] In particular, this allows for full-surface contact of the pressure bodies on the intermediate pressure plates and pressure plates, and thus allows for accurate force determination on each plate via the tube pressure. No special sensors are required for this, which reduces costs. Furthermore, it is not necessary to detect deflections of the pressure plates. Furthermore, lower pressure levels in the tubes can be achieved at the same cell pressure compared to, for example, air bellows. Furthermore, compared to solutions using air bellows, the construction space can be reduced due to the significantly shorter block length. Furthermore, particularly tubular pressure bodies can be integrated into the rectangular, often flat, construction space of a battery module housing or battery module more easily than corresponding air bellows or cylinders, thus providing a high degree of flexibility in construction space. Furthermore, corresponding tubular pressure bodies are very thin and light, which also allows for weight savings. Pressure plates or intermediate pressure plates can likewise be made very narrow and made of thin material. In particular, this allows for a very uniform pressure distribution on the battery cell surface.

[0014] In particular, the present invention solves the problem of clamping at least one battery cell, in particular a plurality of battery cells, within a battery module, and in this case, within a battery module housing. In particular, the battery cells are so-called pouch cells or prismatic cells, which exhibit, for example, enhanced cell breathing. Here, cell breathing refers to a volume change or a state of charge, or the so-called SoC (State of Charge). Therefore, a system for compensating for volume changes is required. Furthermore, many battery cells require a so-called clamping force, i.e., pressure perpendicular to the battery cell surface, to function properly. For example, such clamping force is required in solid-state cells, where layers are pressed against each other via pressure to optimize surface contact and reduce cell resistance. Furthermore, a corresponding clamping force is required for so-called lithium metal anodes, where layers are generated during charging and then removed during discharging. Therefore, so-called cell breathing occurs in particular. Furthermore, clamping such battery cells is required to realize deposition or accumulation processes, allowing the generation and removal of flat layers. This requires, in particular, that pressure be constantly applied to the battery cell, whereby the pressure-regulating member, which may also be referred to as a pressure-applying member, must be in contact with the cell at any time and transmit force, regardless of volumetric changes in the battery cell.

[0015] Furthermore, the first pressure body and / or the second pressure body have reinforcements at their edge regions and / or corner regions. For example, if the battery module housing is provided in a substantially rectangular parallelepiped shape, reinforcements can be provided at the corresponding corners, so that the first pressure body and / or the second pressure body can have a long service life.

[0016] According to an advantageous embodiment, the first and second pressure members are made of a rubber-like material. Therefore, in particular, the first and second pressure members can be provided as a type of bicycle tube. This allows pressure regulation within the battery module housing in a simple manner. In particular, since the rubber-like material is very lightweight and inexpensive, the first and second pressure members can be provided within the battery module housing with high flexibility.

[0017] It is also advantageous if at least the first and second pressure bodies are fluidly connected to one another, so that only a pressure regulating device is required to regulate the pressure in both the first and second pressure bodies, which allows for a reduction in the construction space and the number of components.

[0018] In a further advantageous embodiment, at least the first and second pressure bodies are fluidly connected to one another via a fluid connection that is guided through a cavity in the intermediate pressure plate. This allows the fluid connection between the first and second pressure bodies to be realized in a space-saving manner. The cavity can be provided, for example, in the form of a hole or a cylinder, in which case the first pressure body can be connected or welded to the second pressure body via a rubber or tubular connection as well. This allows for simple yet reliable pressure regulation within the pressure regulating device.

[0019] Furthermore, it has proven advantageous if a filling valve is formed in the module frame for filling the first and / or second pressurized body with a fluid. In particular, the module frame has only one filling valve, in which case the first and / or second pressurized body are fluidly connected to each other in the same way. Thus, the first and / or second pressurized body can be fluidly filled outside the module frame.

[0020] It has further proven advantageous if the shape of the first and / or second pressure body at least partly substantially corresponds to the shape of the second receiving area. In particular, a flexible first and / or second pressure body, in particular a tubular and rubber-like first and / or second pressure body, allows the first and / or second pressure body to be adapted to the shape of the receiving area. Furthermore, the first and / or second pressure body can already have a substantially pre-fabricated shape, for example a substantially rectangular parallelepiped shape, so that an improved pressure distribution can be achieved by the first and / or second pressure body.

[0021] It has also proven advantageous if the cross section of the first and / or second pressure body is substantially oval or substantially circular. This allows for a simple manufacturing process for the first and / or second pressure body. In particular, the first and / or second pressure body is flexible so that, after pressure is applied, the oval or circular shape can be adapted to the corresponding shape of at least the second receiving area. This allows for a reliable and simple adjustment of pressure within the battery module housing.

[0022] Another aspect of the present invention relates to a battery module for electrical energy storage, comprising at least one battery module housing according to the previous aspect and at least one battery cell, the at least one battery cell undergoing a volume change depending on the cell condition.

[0023] Another aspect of the present invention relates to an electric energy storage unit, particularly for an at least partially electrically driven motor vehicle, comprising at least one battery module according to the aforementioned aspect. In particular, for example, the electric energy storage unit can further comprise a second battery module according to the aforementioned aspect. Furthermore, the electric energy storage unit can comprise further battery modules. Furthermore, the electric energy storage unit can have a corresponding management system, for example, for regulating the pressure of the battery modules and monitoring the corresponding state of charge. The electric energy storage unit can, for example, be formed as an electric vehicle battery of an at least partially electrically driven motor vehicle.

[0024] Furthermore, a further aspect of the invention relates to a motor vehicle comprising at least one electric energy store according to the aforementioned aspect, which can in particular be configured as an at least partly electrically driven motor vehicle, in particular as a fully electrically driven motor vehicle.

[0025] A second independent aspect of the present invention relates to a battery module housing for a battery module of an electrical energy storage device, comprising at least one battery cell, the at least one battery cell undergoing a volume change depending on the cell state, and at least one module frame, which defines in the battery module housing at least one first accommodation area for the at least one battery cell and a second accommodation area for a pressure regulating device, the pressure regulating device being at least partially in contact with the at least one battery cell in an assembled state of the battery module and configured to regulate a predetermined value of pressure on the battery cell depending on the volume change, wherein the pressure regulating device has at least one first tubular and flexible pressure body, which is made of a rubber-like material.

[0026] Furthermore, a third independent aspect of the present invention relates to a battery module housing for a battery module of an electrical energy storage device, comprising at least one battery cell, the at least one battery cell undergoing a volume change depending on a cell state, and at least one module frame, which defines in the battery module housing at least one first accommodation area for the at least one battery cell and a second accommodation area for a pressure regulating device, the pressure regulating device being at least partially in contact with the at least one battery cell in an assembled state of the battery module and configured to regulate a predetermined pressure value on the battery cell depending on the volume change, wherein the pressure regulating device comprises at least one tubular flexible pressure body, the at least one pressure body having reinforcements in each edge and / or corner region.

[0027] Advantageous embodiments of the first aspect of the present invention can be considered as advantageous embodiments of a battery module and an electric energy store and a motor vehicle. Likewise, advantageous embodiments of the first aspect of the present invention can be considered as advantageous embodiments of two independent second and third aspects, i.e., as advantageous embodiments of a pressure regulating device with a tubular, flexible pressure body, the pressure body consisting of a rubber-like material and / or the pressure body having reinforcements in each edge region and / or corner region. Features of the first independent aspect can be freely combined with features of the second independent aspect and the third independent feature.

[0028] Further advantages, features and details of the present invention will become apparent from the following description based on preferred embodiments and drawings. The features and combinations of features mentioned in the above description and the following description of the figures and / or shown only in the figures can be used not only in the respective combinations presented, but also in other combinations or alone without departing from the scope of the present invention. [Brief explanation of the drawings]

[0029] [Figure 1] 1 shows a schematic side view of an embodiment of a motor vehicle equipped with an embodiment of an electrical energy storage; [Figure 2] 1 shows a schematic diagram of one embodiment of a battery module. [Figure 3] 3 shows another schematic plan view of the battery module shown in FIG. 2. [Figure 4] 1 shows a schematic perspective view of an embodiment of a pressurizing body of an embodiment of a battery module housing. [Figure 5] 1 illustrates a schematic perspective view of one embodiment of a battery module. DETAILED DESCRIPTION OF THE INVENTION

[0030] In the drawings, identical or functionally identical elements are designated by identical reference numbers.

[0031] 1 shows a schematic side view of an embodiment of a motor vehicle 10 equipped with an embodiment of an electric energy storage unit 12. The motor vehicle 10 can be configured, in particular, as an at least partially electrically driven motor vehicle, in particular as a fully electrically driven motor vehicle. The electric energy storage unit 12 can be configured, for example, as an electric vehicle battery for driving an electric drive of the at least partially electrically driven motor vehicle 10. Furthermore, the electric energy storage unit 12 can be configured to operate the onboard electrical grid of the motor vehicle 10. In this case, in particular, the electric energy storage unit 12 has a first battery module 14 and a second battery module 16.

[0032] FIG. 2 shows a schematic plan view of one embodiment of the battery modules 14, 16. In the following, the corresponding features will be described only for the first battery module 14. However, these features can also be applied to the second battery module 16. Accordingly, FIG. 2 particularly shows the first battery module 14. The battery module 14 has at least one battery cell 18, in particular four battery cells 18. The battery cells 18 are, in particular, so-called solid-state cells that undergo cell breathing, during which a volume change occurs depending on the aging and charge state of the battery cells 18. To enable cell breathing, a pressure regulator 20 is provided according to the present invention. The pressure regulator 20 itself is part of the battery module housing 22.

[0033] The battery module housing 22 is particularly designed for the electrical energy store 12, with at least one battery cell 18 undergoing a volume change depending on the respective cell state. In this regard, the battery module housing 22 has in particular a module frame 24, which at least defines a first receiving area 26 for the at least one battery cell 18 and a second receiving area 28 for a pressure regulating device 20, which, in the assembled state of the battery module 14, is at least partially in contact with the at least one battery cell 18 and is designed to regulate a predetermined value of pressure on the battery cell 18 depending on the volume change.

[0034] Here, the pressure regulating device 20 includes at least a tubular, flexible first pressure body 30 and a separate tubular, flexible second pressure body 32. A movable intermediate pressure plate 34 is formed between the first pressure body 30 and the second pressure body 32, and is in at least partial contact with the first pressure body 30 and the second pressure body 32. In particular, here, the pressure regulating device 20 can also include a third pressure body 36, in which case another intermediate plate 38 is formed between the second pressure body 32 and the third pressure body 36. Furthermore, in this embodiment, it can be seen that a pressure plate 40 is formed between the third pressure body 36 and one of the battery cells 18. For example, if the battery module housing 22 includes only two pressure bodies 30, 32, the pressure plate 40 can be formed between the second pressure body 32 and the battery cell 18. The pressure regulating device 20 can also include more than three pressure bodies 30, 32, 36.

[0035] Figure 3 shows another schematic plan view according to the embodiment shown in Figure 2. In Figure 3, it can be seen that, due to cell breathing, for example of the battery cell 18, the pressure regulator 20 accordingly "inflates" the pressurizing bodies 30, 32 and 36, thus adapting the pressure values. In particular, it can be seen here that the pressurizing bodies 30, 32 and 36 are supported on the module frame 24. Furthermore, the battery cell 18 is also supported on the module frame 24.

[0036] In particular, the first pressure body 30 and / or the second pressure body 32, and here also the third pressure body 36, can be made from a rubber-like material, which can also be considered an independent aspect of the invention.

[0037] 3 further shows that at least the first pressure body 30 and the second pressure body 32 are connected to one another via a fluid connection 42. Furthermore, in this embodiment, the second pressure body 32 is fluidly connected to the third pressure body 36 via the fluid connection 42. In particular, here the fluid connection 44 can be guided through a cavity 44 in the intermediate pressure plate 34.

[0038] FIG. 3 further shows that a fill valve 46 is formed in the module frame 24 for filling the first pressurized body 30 and / or the second pressurized body 32 with fluid.

[0039] Furthermore, the shape of the first pressure body 30 and / or the second pressure body 32 can at least partially correspond substantially to the shape of the second receiving area 28, and in this case, the cross section of the first pressure body 30 and / or the second pressure body 32 can be formed to be substantially oval or substantially circular.

[0040] 2 and 3 show that a fluid can be pumped through elastic tubes or pressure bodies 30, 32, 36, which may be compressible, such as air, or incompressible, such as liquid. The pressure bodies 30, 32, 36 are in particular tubes, but may also have other shapes, such as rubber balloons or bellows. In the case of tubes, the cross section may be circular or elliptical, for example. The open ends of the tubes may be closed, for example, by welding.

[0041] The tubes themselves are not self-supporting; they are supported by the module frame 24, which allows them to be very thin and flexible, resulting in a very high degree of deformability. This support allows the tubes to be inflated to pressures much higher than would be possible without the sheath. Pressures exceeding 16 bar can be achieved, making it possible to use similar materials, particularly those used in the bicycle industry. As the thin tubes inflate, they fill the cavity of the module's structural form, which is typically rectangular. The material is flexible enough to allow the tubes to conform to the geometry of the module. The module's cavity is designed to prevent damage from sharp edges. The radius ensures good tube contact. Corresponding gaps are minimized. Another possibility is for the tubes to plastically deform upon initial inflation, taking on the shape of the module's cavity. As mentioned above, the tubes are typically oval in shape. However, it is also conceivable to design the tubes so that they expand into a square shape within the cavity. Additionally, the tubing may be reinforced in certain locations, for example to protect bends / radii.

[0042] To achieve a larger stroke, multiple tubes can be inserted one after the other and separated by thin plates. These plates, specifically referred to as intermediate pressure plates 34, do not serve as mechanical supports but simply serve as abutment surfaces between the air tubes, thereby preventing changes in the shape of the air tubes. When multiple tubes are connected one after the other, they are connected via corresponding air connections, such as valves or locking devices, that equalize the fluid pressure between the tubes. Fluid is supplied to one of the tubes, specifically the tube located at the module edge, specifically the first pressure body 30. This valve is a pressure-regulating valve that measures and regulates the pressure in the tube. The valve and air connections are specifically mounted in the center of the intermediate pressure plate 34 and the pressure bodies 30, 32, and 36. The pressure valve allows the pressure in the tube to be controlled. Other valves and connecting elements can also be used depending on the fluid used, without limiting the invention.

[0043] Since the tube is always in contact over its entire surface with the intermediate pressure plate 34 and the pressure plate 40, which marks the transition to the battery cell 18, the pressure on the battery cell 18 at any given time can be determined via the pressure inside the tube. This can only be achieved if the tube is thin and flexible, so that it completely fills the cavity and takes the shape of the cavity at minimum pressure. If the material has already plastically deformed and taken the geometric shape of the cavity after the first pumping, this shape will be maintained even at very low pressures.

[0044] 4 shows a schematic perspective view of one embodiment of the pressure bodies 30, 32, 36. This embodiment shows in particular that the pressure bodies 30, 32, 36 have a substantially rectangular shape and are adapted to the shape of the battery module housing 22. Furthermore, it is particularly shown that the corresponding corner regions 48 are provided with reinforcements 50, which prevent damage to the pressure bodies 30, 32, 36. This embodiment is also an independent aspect of the invention that can be considered either in combination with the two pressure bodies 30, 32 or alone.

[0045] FIG. 5 shows a schematic perspective view of one embodiment of a battery module 14. The module frame 24 is particularly shown. Three pressure bodies 30, 32, and 36 are also shown. The pressure bodies 30, 32, and 36 are separated from one another by intermediate pressure plates 34 and 38, respectively. A pressure plate 18 is also disposed between the third pressure body 36 and the battery cells 18. In this embodiment, the battery module 14 includes multiple battery cells 18. In particular, in this embodiment, the battery cells 18 are disposed within cassette guides 52, which can move within the module frame 24 during cell respiration. In other words, the battery cells 18 are movably suspended on corresponding rails 54 and can expand accordingly in response to cell respiration and pressure regulation. 5 shows that the battery cells 18 are supported in particular on a first side wall 56 of the module frame 24, and that the first pressure body 30 is supported on a second side wall 58 located opposite the first side wall 56. This support also allows a corresponding pressure value to be adjusted within the battery module 14 via pressure control and expansion of the battery cells 18.

Claims

1. A battery module housing (22) for a battery module (14, 16) of an electrical energy storage unit (12), the battery module housing (22) having at least one battery cell (18), the at least one battery cell (18) undergoing a volume change depending on a cell state, the battery module housing (22) having at least one module frame (24), the at least one module frame (24) forming at least one first accommodation area (26) for the at least one battery cell (18) and a second accommodation area (28) for a pressure regulating device (20) of the battery module housing (22); the pressure adjusting device (20) is configured to at least partially contact the at least one battery cell (18) when the battery modules (14, 16) are assembled, and to adjust a predetermined value of pressure on the battery cell (18) in response to the volume change; In the battery module housing (22), the pressure regulating device (20) has at least a tubular, flexible first pressure body (30) and a separate tubular, flexible second pressure body (32), and a movable intermediate pressure plate (34) is formed between the first pressure body (30) and the second pressure body (32) and is in at least partial contact with the first pressure body (30) and the second pressure body (32). The battery module housing (22) is characterized in that the first pressure body (30) and / or the second pressure body (32) are rectangular in shape and have reinforcing portions (50) formed in each edge region and / or each corner region (48).

2. The battery module housing (22) according to claim 1, characterized in that the first pressure body (30) and / or the second pressure body (32) are made of a rubber-like material.

3. 3. The battery module housing (22) according to claim 1 or 2, characterized in that at least the first pressurizing body (30) and the second pressurizing body (32) are fluidly connected to each other.

4. 4. The battery module housing (22) according to claim 3, characterized in that at least the first pressure body (30) and the second pressure body (32) are fluidly connected to each other via a fluid connection (42) guided through a cavity (44) in the intermediate pressure plate (34).

5. 3. The battery module housing (22) according to claim 1 or 2, characterized in that the module frame (24) is formed with a filling valve (46) for filling the first pressurizing body (30) and / or the second pressurizing body (32) with a fluid.

6. 3. The battery module housing (22) according to claim 1 or 2, characterized in that the shape of the first pressure body (30) and / or the second pressure body (32) corresponds at least in part to the shape of the second accommodating area (28).

7. 3. The battery module housing (22) according to claim 1 or 2, wherein the cross section of the first pressure body (30) and / or the second pressure body (32) is formed in an oval or circular shape.

8. A battery module (14, 16) for an electrical energy storage unit (12), comprising at least one battery module housing (22) according to claim 1 or 2, and at least one battery cell (18), the at least one battery cell (18) undergoing a volume change depending on a cell state.

9. 10. An electric energy store (12), in particular for an at least partly electrically driven motor vehicle (10), said electric energy store (12) comprising at least one battery module (14, 16) according to claim 8.

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