Battery module, method for assembling the battery module, and vehicle

Abstract

The invention relates to a cell holder (1) comprising a separating wall (2) and two sliding guide elements (3) which are provided on opposite edges of the separating wall (2) and are configured so that when arranged in a packaging space (4) of a module frame (5) each is supported via sliding guide surfaces (6) that positively fit sliding guide rails (7) on the module frame (5), wherein at least two cell holders (1) can be stacked orthogonally to a plane of extension (E) of the separating wall (2) to form a cell receptacle for a galvanic cell (8), wherein in their stacked condition cell holders (1) can be moved relative to the module frame (5) and relative to one another in the stacking direction (SR). The cell holder according to the invention is characterized in that each of the sliding guide elements (3) has an opening (9) through which cell surge protectors (10) of galvanic cells (8) can pass, and also has an electrically conductive clamping element (11) for clamping the cell surge protectors (10) in the opening (9); and each of the sliding guide elements (3) has at least one connection element (12) for mechanically connecting an additional component (13).

Description

[0001] Mercedes-Benz Group AG

[0002] Battery module, method for mounting the battery module and vehicle

[0003] The invention relates to a battery module of the type defined in more detail in the preamble of claim 1, a method for assembling the battery module and a vehicle.

[0004] Battery cells can change their volume over their lifespan. This is particularly true for battery cells with lithium anodes. During a charge or discharge cycle, the battery cells can expand and contract. This phenomenon is also known as "breathing" or "cell breathing." In addition, volume changes occur due to aging.

[0005] Typically, several battery cells are electrically connected to each other to achieve a desired cell voltage or capacity. The battery cells are arranged within a housing. Several battery cells can be connected together to form modules. Each battery module or battery must be designed so that changes in the volume of the individual battery cells do not adversely affect their operation. In particular, sufficient space should be provided to accommodate these volume changes. If the battery cells are restricted in their expansion, they will be compressed against each other and subjected to pressure. This can cause the materials from which the battery cells are made to wear down and accelerate the aging of the battery cells.

[0006] German patent application DE 102020 003 892 B4 discloses a cell holder for at least one battery cell and a cell module. The document describes a carrier for battery cells. The carrier consists of essentially rectangular walls that can be stacked in a stacking direction. Cavities are formed between the individual walls, which serve to hold the battery cells. The arrangement of battery cells and carrier is inserted into a module frame of a corresponding battery module. The respective carriers are supported on the module frame by corresponding guide structures. The carriers are not fixed relative to the module frame in the stacking direction, so that the carriers can move together with the battery cells in the stacking direction. This allows the aforementioned volume changes of the battery cells to be accommodated. The battery cells are preferably so-called pouch cells.

[0007] During operation, it is essential to monitor the battery cells to verify that the battery is functioning within its intended parameters. The mobility of the battery cells relative to one another complicates this monitoring. Furthermore, the demands on the electrical interconnection of relevant electronic components increase. Assembling a battery module is also challenging. Therefore, maintaining the safety of the individual battery components, particularly preventing short circuits, is a critical task under these demanding conditions.

[0008] The operating parameters of a corresponding battery module can be monitored by means of a dedicated processing unit, usually implemented as a so-called system-on-a-chip (SoC). This allows the galvanic cells to be electrically connected to the processing unit, enabling the acquisition of electrical parameters such as the voltage and / or current of each individual cell. Furthermore, dedicated sensor elements, such as temperature sensors, can be incorporated to monitor, for example, the temperature of a galvanic cell. Due to the mobility of the galvanic cells relative to each other, connecting them to the processing unit is challenging. A reliable connection to the processing unit must be possible regardless of the position of the galvanic cells. In particular, no connecting cables may break during operation. The relative movement of the galvanic cells to one another must not be restricted.Furthermore, all components must be designed in such a way as to prevent short circuits between them.

[0009] Furthermore, US 2019 / 0067762 A1 discloses a fastening element, a battery unit, and a battery module. The fastening element comprises a thermally conductive plate for mounting a battery cell. Several fastening elements with battery cells attached to them can be stacked to form a cell stack. On both sides, transverse to the stacking direction, each fastening element has a projection extending along its height. Openings are located at the top and bottom of this projection for attaching a housing cover. For this purpose, the housing cover has projections arranged in a row adjacent to each other. Because the housing cover is rigid and the projections are monolithic to it, the fastening elements are held immovably relative to the housing cover and thus to the housing of the battery module in the stacking direction.

[0010] Furthermore, CN 219937259 U discloses a battery module with pouch cells. The battery module also comprises a cell stack consisting of a multitude of battery cells arranged by means of mounting elements. Here, too, the mounting elements consist of a plate and sliding guide elements arranged laterally to it. The sliding guide elements have holes for the passage of rods in the stacking direction. A collector plate can be connected laterally to each mounting element between the rods in the vertical direction. The collector plates each have an opening for the passage and attachment of cell terminals. The collector plates of adjacent mounting elements are attached to one another in the stacking direction, so that the mounting elements with the battery cells are also immobile relative to each other in the stacking direction.

[0011] Furthermore, DE 102014 019 074 A1 discloses a cell block for a

[0012] Motor vehicle battery. Here too, the movement of adjacent cell holders with battery cells of a cell stack is prevented by two cover plates connected to the respective end faces.

[0013] Furthermore, CN 214753951 U reveals a module frame for lithium-ion pouch cells.

[0014] The present invention is based on the objective of providing an improved battery module with cell holders which meets the requirements described above.

[0015] According to the invention, this problem is solved by a battery module with the features of claim 1. Advantageous embodiments and further developments, as well as a method for mounting the battery module and a vehicle with such a battery module, are set forth in the dependent claims.

[0016] A battery module of this type, comprising a module frame, at least one galvanic cell and at least two cell holders, each cell holder comprising a partition and two sliding guide elements provided on opposite edges of the partition, which are configured to support themselves positively against sliding guide rails of the module frame via sliding guide surfaces when arranged in a packaging space of a module frame, wherein at least two cell holders are stackable orthogonally to a plane of extension of the partition to form a cell receptacle for a galvanic cell, wherein each cell holder is movable relative to the module frame and to each other in the stacking direction when stacked, further provides thatthat the sliding guide elements each have a recess for guiding cell arresters of galvanic cells through them, as well as an electrically conductive clamping element for clamping the cell arresters in the recess; and that the sliding guide elements each have at least one connection element for mechanically connecting an additional component, and is further developed according to the invention in that, as an additional component, at least one clamping element cover for the clamping element of at least one of the cell holders, a circuit board and a circuit board cover for the circuit board are connected to at least one of the respective cell holders.

[0017] The clamping elements allow the cell arresters of the galvanic cells to be reliably fixed in the corresponding recess when the cells are arranged on the cell holder. Each sliding guide element also has at least one connection element for attaching additional components to the cell holder. As will be described later, this allows for the particularly simple and reliable connection of components such as insulating shields, a processing unit for recording and processing the operating parameters of the galvanic cells, and the like. Since the respective components are connected directly to the cell holder, they can move with it. This prevents the cell holder's freedom of movement in the stacking direction from being restricted or even completely blocked by the additional components.This allows the mobility of the cell holder to be maintained, thus ensuring reliable operation of a corresponding battery module.

[0018] Preferably, the clamping element and the connection element are located on the same side of their respective sliding guide elements, so that the electrical connection of the battery module components and the execution of assembly steps are only required on one side. This simplifies the assembly of the battery module.

[0019] The terminal element cover and the circuit board cover are preferably made of an electrically insulating material. The terminal element cover protects the cell arresters of the galvanic cells from contact with other conductive components of the battery module, thus preventing short circuits. The terminal element cover moves with the respective cell holders, ensuring reliable protection of the cell arresters regardless of their position. The circuit board can be equipped with a processing unit for acquiring and analyzing the operating parameters of the battery module. The circuit board can be connected to any cell holder, particularly one located centrally in the stacking arrangement. The circuit board cover allows for the monitoring of the electrical and / or...Protect the electronic components of the circuit board from short circuits, contamination, and / or mechanical damage. Especially when multiple connection elements are provided for on the same cell holder, several of the additional components can be connected to a single cell holder. It is also conceivable to use a hollow screw as a fastener, for example, to attach the circuit board to a cell holder and then secure the board cover with a solid screw in the hollow screw.

[0020] An advantageous embodiment of the battery module according to the invention provides that at least two connection elements are provided for at least one cell holder for connecting at least two additional components to a respective sliding guide element. This allows not only one additional component, but several additional components to be provided for each cell holder. Furthermore, a single additional component can be fixed particularly reliably. According to a further advantageous embodiment of the battery module according to the invention, at least one connection element for at least one cell holder is formed by a threaded insert or an opening for the passage of a fixing pin. Thus, a respective sliding guide element can have a recess, such as a cylindrical recess. A threaded set can be inserted into this recess.The threaded insert is fixed in this recess, for example by screwing it in, gluing it in, or similar methods. The additional component can then be attached to the threaded insert using a screw. Instead of screws, fixing pins can also be used. For this purpose, a through-hole can be provided in one of the sliding guide elements. Fixing pins can also be secured within the threaded insert.

[0021] A further advantageous embodiment of the battery module according to the invention provides that at least one connection element for at least one cell holder is embedded in a projection of the sliding guide element, which has a sliding guide surface. The projection extends particularly far from the cell holder, thus providing excellent accessibility to the connection element. This further facilitates the attachment of corresponding additional components. Moreover, due to the spatial proximity, there is a geometric relationship between the respective connection elements and the clamping element. This makes it particularly advantageous to attach additional components that are related to the clamping element or the cell terminals, for example, in the form of an insulating cover.

[0022] According to a further advantageous embodiment of the battery module according to the invention, the partition and the sliding guide elements for at least one cell holder are designed as multi-part components. This increases the flexibility in the manufacture of individual cell holders and the adaptation of the cell holders to the respective operating conditions. For example, the partition can be made of metal, which promotes mechanical rigidity and stability while simultaneously ensuring good heat dissipation. The sliding guide elements are preferably made of plastic, which allows for low static friction between the sliding guide surfaces and the sliding guide rails of the module frame. Furthermore, the sliding guide elements can be manufactured cost-effectively, for example, by injection molding. However, a monolithic design of the partition and sliding guide elements is also possible.Preferably, at least one additional component is connected exclusively to a single cell holder. Generally, it is conceivable that an additional component is connected to multiple cell holders. However, this can restrict the movement of the cell holders in the stacking direction. This may, however, be desirable. If the additional component is attached exclusively to a single cell holder, the cell holder can continue to move freely in the stacking direction.

[0023] A further advantageous embodiment of the battery module according to the invention provides that the processing board has a cable guide for receiving and routing connecting cables, wherein the processing board is electrically connected via the respective connecting cables to the respective galvanic cells and / or sensors arranged on the respective cell holders. As already described, this enables the processing board to monitor the operating parameters of the respective galvanic cells. The cable guide allows for space-efficient and reliable routing of the connecting cables to the processing board. This prevents the connecting cables from dangling freely in the packaging space, which increases the risk of the connecting cables becoming caught on components in the packaging space during relative movement of the cell holders and galvanic cells. This could lead to the corresponding connecting cables being torn off.The circuit board cover provides additional protection against short circuits and corresponding mechanical damage.

[0024] According to the invention, a method for assembling the battery module comprises the following process steps:

[0025] - Forming a cell stack consisting of at least two cell holders and a galvanic cell arranged between the cell holders in the cell receptacle;

[0026] - Attaching the respective clamping element cover for each clamping element;

[0027] - Attaching the computer board;

[0028] - Attaching the circuit board cover; and

[0029] - Introducing the cell stack into the packaging space.

[0030] As previously described, the terminal cover protects both the terminal element and the respective cell arresters. The circuit board can then be placed on one of the cell holders, facing the partition. The terminal cover prevents short circuits between the circuit board and the terminal element, or between the circuit board and the cell arrester. Specifically, the terminal cover is secured to a terminal element or a threaded insert provided on a terminal element using fixing pins, and the circuit board is secured to the terminal element using screws. The circuit board cover can then be attached. This cover can also be attached to one of the cell holders or directly to the circuit board.

[0031] Forming the cell stack involves additional steps, such as clamping the cell arresters to the clamping element and welding the cell arresters to each other and / or to the clamping element. Further assembly steps may include connecting sensors and wiring galvanic cells. Connection points for the control board may also be provided, for example, in the form of plug connectors for electrical contact or reading data signals. After the control board is in place, the corresponding plug connections can be made using connecting cables.

[0032] According to the invention, a vehicle is further developed by an at least partially electrified powertrain, wherein a traction battery provided for supplying the powertrain comprises at least one battery module as described above. The battery module according to the invention is characterized by quick and easy assembly. This reduces manufacturing costs. Furthermore, particularly reliable operation is possible because the respective cell holders and galvanic cells can move freely in the stacking direction during operation, and protection against short circuits is improved. The vehicle can be any road vehicle such as a car, truck, van, bus, or the like. It could also be a rail vehicle, watercraft, or aircraft.

[0033] Further advantageous embodiments of the cell holder, the battery module and the method for mounting the battery module according to the invention will also be evident from the exemplary embodiments which are described in more detail below with reference to the figures.

[0034] This shows:

[0035] Fig. 1 shows a schematic representation of a cell holder according to the invention;

[0036] Fig. 2 is a schematic representation of a battery module according to the invention; Fig. 3 is a schematic detail representation of several sliding guide elements of adjacent cell holders;

[0037] Fig. 4 shows a schematic exploded view of several additional components that can be connected to the stacked cell holders; and

[0038] Fig. 5 shows a schematic detail of a computer board and a board cover.

[0039] Figure 1 shows a cell holder 1 according to the invention, comprising a partition 2 and two sliding guide elements 3 arranged on opposite edges of the partition 2. The partition 2 extends in a plane E, and several cell holders 1 can be stacked relative to each other in a stacking direction SR orthogonal to the plane E. Two adjacent partitions 2 each form a cell receptacle for galvanic cells 8 shown in Figure 2. In the embodiment shown, the galvanic cells 8 are pouch cells.

[0040] As shown in Figure 2, the cell holders 1 and galvanic cells 8 stacked in this manner can be inserted into the packaging space 4 of a module frame 5 to form a battery module 16.

[0041] The sliding guide elements 3 have sliding guide surfaces 6 which are positively engaged with sliding guide rails 7 of the module frame 5. This allows the cell holders 1 to be laterally fixed within the module frame 5, while each cell holder 1 remains movable relative to each other and relative to the module frame 5 in the stacking direction SR. Thus, the cell holders 1 and galvanic cells 8 can move in the stacking direction SR as the volume of the galvanic cells 8 increases or decreases. The resulting volume changes of the galvanic cells 8 can therefore be compensated, thereby minimizing the mechanical stress on the galvanic cells 8. The galvanic cells 8 can be electrically connected via cell connectors 10 shown in Figure 3. The cell connectors 10 can be fixed in recesses 9 of the sliding guide elements 3 by means of the clamping elements 11 shown in Figure 1.

[0042] Figure 3 shows an enlarged view of several sliding guide elements 3 of respective cell holders 1. Two adjacent connecting elements 12 for additional components 13 shown in Figures 4 and 5 are shown on those projections of the sliding guide elements 3 that also form the sliding guide surfaces 6. In the illustrated embodiment, threaded inserts 14 are provided as connecting elements 12.

[0043] The connection elements 12 are particularly preferably provided on the side where the terminal elements 11 or cell connectors 10 also point away from the respective cell holders 1. This allows assembly or pre-assembly steps to be carried out on only one side of a corresponding cell stack 21 shown in Figure 4, which simplifies the effort required to assemble the cell stack 21 and thus the battery module 16.

[0044] Additional components 13 can be attached to the respective cell holders 1 using the connecting elements 12. In Figures 4 and 5, these additional components 13 are several terminal element covers 17, a computation board 18, and a circuit board cover 19. For clarity, only some of the same elements are shown with the same reference numerals.

[0045] The clamping element covers 17 are fastened in the threaded inserts 14 with fixing pins 15. Instead of threaded inserts 14, openings (not shown) for receiving said fixing pins 15 could also be provided.

[0046] The terminal element covers 17 are made of an electrically insulating material, for example, rubber, silicone, plastic, or the like. Preferably, one terminal element cover 17 covers several terminal elements 11 or cell arresters 10 in the stacking direction SR. The terminal element covers 17 are sufficiently wide or stretchable in the stacking direction SR to ensure reliable coverage of the respective cell arresters 10 and terminal elements 11, even during relative movement of the cell holders 1 and galvanic cells 8 in the stacking direction SR.

[0047] The computing board 18 is preferably fastened to threaded inserts 14 by means of screws 22. Particularly preferably, two screws 22 per side are used, i.e., a total of four screws 22, since the computing board 18 is heavy and / or sensitive with regard to its mechanical load-bearing capacity compared to the terminal element covers 17. Particularly preferably, the circuit board 18 is screwed to threaded inserts 14 on both opposite sides of the same sliding guide element 3. This ensures a reliable mechanical connection to the respective cell holder 1. Figure 5 also shows the circuit board cover 19, shown here in white, detached from the computing board 18. This allows a view of the cable routing on the computing board 18 as well as connecting cables 20 for connecting the computing board 18 to the cell arresters 10 or the terminal elements 11 and / or sensors (not shown) for recording operating parameters of the galvanic cells 8.

[0048] For example, the temperature of the galvanic cells 8 or a force acting on a galvanic cell 8 can be measured in this way. The connecting cables 20 can be connected to the connectors 23 provided on the respective cell holders 1 for this purpose.

[0049] The circuit board cover 19 can also be attached to corresponding connection elements 12 of cell holders 1. In the embodiment shown in Figures 4 and 5, however, the circuit board cover 19 is attached to the computing board 18 itself.

[0050] For example, the circuit board cover 19 can be clipped onto corresponding support elements of the computing board 18.

[0051] Preferably, all additional components 13 are connected exclusively to a single cell holder 1. This prevents the relative mobility of the cell holders 1 and galvanic cells 8 in the stacking direction SR from being restricted or even prevented. Thus, particularly reliable operation of the battery module 16 comprising the cell stack 21 is possible.

Claims

Mercedes-Benz Group AG Patent claims 1. Battery module (16) comprising a module frame (5), at least one galvanic cell (8) and at least two cell holders (1), each cell holder (1) comprising a partition (2) and two sliding guide elements (3) provided on opposite edges of the partition (2), which are configured to be positively supported on sliding guide rails (7) of the module frame (5) via sliding guide surfaces (6) when arranged in a packaging space (4) of a module frame (5), wherein at least two cell holders (1) are stackable orthogonally to an extension plane (E) of the partition (2) to form a cell receptacle for a galvanic cell (8), wherein each cell holder (1) is movable relative to the module frame (5) and to each other in the stacking direction (SR) when stacked.wherein the sliding guide elements (3) each have a recess (9) for guiding cell arresters (10) of galvanic cells (8) through it, and an electrically conductive clamping element (11) for clamping the cell arresters (10) in the recess (9); and the sliding guide elements (3) each have at least one connecting element (12) for mechanically connecting an additional component (13), characterized in that the additional component (13) is at least one clamping element cover (17) for the clamping element (11), at least one of the cell holders (1), a circuit board (18), and a circuit board cover (19) for the circuit board (18) connected to at least one of the respective cell holders (1).

2. Battery module (16) according to claim 1, characterized by at least one cell holder (1) with at least two connection elements (12) for connecting at least two additional components (13).

3. Battery module (16) according to claim 1 or 2, characterized in that for at least one cell holder (1) at least one connection element (12) is formed by a threaded insert (14) or an opening for passing a fixing pin (15).

4. Battery module (16) according to one of claims 1 to 3, characterized in that for at least one cell holder (1) at least one connection element (12) is embedded in a projection of the sliding guide element (3) having the sliding guide surface (6).

5. Battery module (16) according to one of claims 1 to 4, characterized in that for at least one cell holder (1) the partition (2) and the sliding guide elements (3) are designed in multiple parts relative to each other.

6. Battery module (16) according to one of claims 1 to 5, characterized in that at least one of the additional components (13) is connected exclusively to a single cell holder (1).

7. Battery module (16) according to one of claims 1 to 6, characterized in that the computing board (18) has a cable guide for receiving and guiding connecting cables (20), wherein the computing board (18) is electrically connected via respective connecting cables (20) to respective galvanic cells (8) and / or sensors arranged on respective cell holders (1).

8. Method for assembling a battery module (16) according to one of claims 1 to 7, characterized by the following method steps: - Forming a cell stack (21) from at least two cell holders (1) and a galvanic cell (8) arranged between the cell holders (1) in the cell receptacle; - Attaching the respective clamping element cover (17) for each clamping element (11); - Attaching the computation board (18); - Attaching the circuit board cover (19); and - Introducing the cell stack (21) into the packaging space (4).

9. Vehicle characterized by an at least partially electrified powertrain, wherein a traction battery provided for supplying the powertrain comprises at least one battery module (16) according to one of claims 1 to 7.

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