Energy storage module consisting of several prismatic storage cells

Abstract

Energy storage module (1) for a device for supplying power, in particular to a motor vehicle, comprising - several prismatic memory cells (2) which are stacked in at least one row (9) and arranged one behind the other, - two end plates (3) and at least one tension element (4), wherein the at least one row (9) of stacked storage cells (2) is tensioned between the two end plates (3) via the tension element (4), and - at least one thermally insulating molded part (8) between one of the end plates (3) and the storage cell (2) adjacent to the end plate (3), wherein at least one pocket (10) is formed in one of the molded part surfaces (11) of the molded part (8) facing the adjacent storage cell (2), so that the adjacent storage cell (2) does not lie completely against the molded part (8).

Description

[0001] The invention relates to an energy storage module for a voltage supply device, in particular of a motor vehicle, comprising a plurality of prismatic storage cells which are arranged one behind the other, stacked at least in one row.

[0002] In a device commonly referred to as a battery for supplying power to a motor vehicle, a plurality of energy storage modules are usually used to power the vehicle, for example, electric vehicles or hybrid vehicles. Each energy storage module typically consists of several stacked prismatic storage cells. The individual storage cells contain electrochemical cells of the battery. The row of stacked storage cells is preferably clamped between two end plates. The two end plates are connected to one another via tension elements. The tension direction is thus perpendicular to the end plates. In addition to mechanically fixing the modules to one another, the end plates and tension elements serve in particular to counteract deformation due to changes in gas pressure that occur during operation in the electrochemical cells arranged inside the modules.

[0003] Especially in a motor vehicle, the energy storage device is exposed to a wide range of thermal stresses. In winter, depending on the application, the extreme ambient temperature of the vehicle must be taken into account. In summer, the high ambient temperature is compounded by the stress from the exhaust system. Here, high radiation input can cause temperatures of over 100°C. Lithium-ion cells should be operated in an ideal operating temperature range between 20°C and 40°C.

[0004] For an optimal operating strategy, a very small temperature difference between the individual cells of the energy storage module is particularly necessary.

[0005] EP 2 403 032 A1 and EP 2 056 392 A1 disclose battery packs having layers provided with ventilation channels between the battery cells to enable convective cooling of the battery cells. The battery packs are held together by connecting plates, which engage with projections provided on the battery cells, thus forming a positive connection.

[0006] The object of the present invention is to provide an energy storage module that can be operated as efficiently as possible while being cost-effective to manufacture and assemble.

[0007] The problem is solved by independent claim 1. The dependent claims relate to preferred developments of the invention.

[0008] The object of the invention is thus achieved by an energy storage module for a voltage supply device. The energy storage module or voltage supply device is used in particular for driving a motor vehicle. The energy storage module comprises a plurality of prismatic storage cells which are stacked one behind the other in at least one row. Furthermore, two end plates and at least one tension element are provided, wherein the at least one row of stacked storage cells is braced between the two end plates via the tension element. According to the invention, a thermally insulating molded part is inserted between the end plate and the storage cell adjacent to the end plate. Particularly preferably, at least one of these molded parts is used per end plate. The molded part consists of a thermally and electrically insulating material.According to the invention, at least one pocket is formed in a molded part surface facing the adjacent storage cell.

[0009] This pocket has the effect that the adjacent storage cell no longer rests fully against the molded part, but rather, thanks to the pocket, an air space or air cushion is formed between the molded part and the adjacent storage cell. This air cushion or pocket promotes thermal insulation between the adjacent storage cell and the end plate. In contrast to conventional arrangements, this improves thermal insulation and allows the molded part to be formed with the smallest possible wall thickness. According to the invention, the air cushion is formed by means of a pocket and not by means of an opening in the molded part, thus always ensuring electrical insulation between the storage cell and the end plate.

[0010] The improved thermal insulation between the storage cell and the end plate according to the invention ensures that the desired temperature of the storage cells can be maintained even at high or low outside temperatures. In particular, the good thermal insulation to the outside promotes the smallest possible spread between the temperatures of the individual storage cells. The energy storage module according to the invention thus enables optimized temperature management of the energy storage device, which in turn leads to increased efficiency.

[0011] In a preferred embodiment, the molded part is plate-shaped. A first side of this plate shape rests against the end plate. A second side of the plate shape, opposite the first side, rests against the adjacent storage cell.

[0012] The surface of the storage cell facing the end plate is referred to as the storage cell front surface. The storage cells are shaped and arranged such that the side of the storage cell with the largest surface area is preferably the storage cell front surface and thus faces the end plate. This side with the largest surface area allows the storage cells to be optimally clamped using the end plate and tension element. At the same time, however, sufficient thermal insulation must also be provided due to the large surface area. This is made possible by the molded part according to the invention. The storage cell front surface facing the end plate is preferably a flat surface.

[0013] To ensure sufficient electrical insulation, the molded part preferably extends over the entire memory cell front surface facing the end plate.

[0014] The size of the pocket in the molded part and thus also the size of the air cushion for optimizing thermal insulation are subject to two essential design criteria. Firstly, the pocket cannot be made too large because the clamping force from the end plate is transferred to the storage cells via the molded part. Accordingly, the molded part must rest against the adjacent storage cell with a sufficiently large area. Secondly, the pocket should be as large as possible in order to obtain a sufficiently large air cushion for thermal insulation. To meet both criteria, it is defined that 10 to 90%, preferably 30 to 70%, of the storage cell front surface facing the end plate lies directly on the molded part over its entire surface and the remaining portion of the storage cell front surface facing the end plate is spaced from the molded part by the at least one pocket.

[0015] To ensure sufficient stability and improve thermal and electrical insulation, the molded part preferably has a wall thickness between 1 mm and 5 mm. The depth of the pocket in the molded part is between 0.5 mm and 3 mm. The expert recognizes that the pocket should not penetrate the molded part and therefore selects a pocket depth that is less than the wall thickness of the molded part.

[0016] The molded part can also have angled wings on its main surface, which separates the end plate from the adjacent storage cell. These wings allow the molded part to at least partially cover at least one storage cell side surface of the adjacent storage cell, thus ensuring thermal and / or electrical insulation on these side surfaces as well.

[0017] The molded part is preferably manufactured in one piece. An injection molding process is particularly suitable for this. It is particularly preferred that the molded part not be made of a typical heat-insulating material, such as foamed plastic. In the preferred embodiment, the molded part has no open or closed pores, thus ensuring sufficient stability with the smallest possible wall thickness.

[0018] Advantageously, the tension elements are designed as tension rods. Alternatively, the tension elements can also be designed as one or more tensioning straps or as combinations consisting of a number of bolts and nuts.

[0019] Further details, features, and advantages of the invention will become apparent from the following description and the figures. They show: Fig. 1 an energy storage module according to the invention according to an embodiment, Fig. 2 a detail of the energy storage module according to the invention according to the embodiment in exploded view, and Fig. 3 the thermally insulating molded part of the energy storage module according to the invention according to the embodiment.

[0020] Fig. 1 shows a storage module 1 according to the exemplary embodiment. The storage module 1 is composed of two rows 9. Each row 9 has six prismatic storage cells 2. The stacked storage cells 2 are clamped together via two parallel end plates 3 and tension elements designed as three tension rods 4. The tensioning exerts the indicated tension force F on the storage cells 2. In the example shown, the energy storage module 1 comprises several rows 9. However, the invention can just as well be implemented on an energy storage module 1 with only one row 9. The fact that the tension elements are designed as tension rods in the present exemplary embodiment should not have a limiting effect on the invention. Of course, the tension elements can also be designed as one or more tensioning straps or as combinations consisting of a number of screws and nuts.

[0021] Fig. 2 shows an exploded view of one of the end plates 3 and a storage cell 2 adjacent to the end plate 3. A molded part 8 for thermal and electrical insulation is arranged between the end plate 3 and the storage cell 2. Fig. 2 shows in contrast to Fig. 1 a slightly different construction of the end plate 3. In particular, the Fig. 2 shows the end plate 3 for an energy storage module 1 with a row 9 of storage cells 2. However, for the illustration of the invention and the exemplary embodiment, it is irrelevant whether the storage module 1 has one or two rows 9. What is crucial is that the molded part 8 is arranged between the end plate 3 and the storage cell 2 adjacent to the end plate 3.

[0022] Fig. 3 shows the molded part 8 in detail. The molded part 8 is plate-shaped and has a first molded part surface 11 and a second molded part surface 12. The first molded part surface 11 faces the storage cell 2. The second molded part surface 12 faces the end plate 3. Accordingly, the molded part 8 rests against the storage cell 2 with the first molded part surface 11. The molded part 8 rests against the end plate 3 with the second molded part surface 12. Thus, the clamping force F can be transmitted from the end plate 3 to the row 9 of storage cells 2 via the molded part 8.

[0023] The Fig. The storage cell 2 shown in Figure 2 has two terminal poles 5 on its upper side. The side facing the end plate 3 is referred to as the storage cell front surface 6. Storage cell side surfaces 7 are perpendicular to the storage cell front surface 6. The molded part 8 has side wings 13 that cover the storage cell side surfaces 7.

[0024] Fig. Figure 3 shows the first molded part surface 11 of the molded part 8 facing the storage cell front surface 6. A pocket 10 is arranged in this first molded part surface 11. In the assembled state, the storage cell front surface 6 does not rest against the first molded part surface 11 via the surface of the pocket 10. Thus, the pocket 10 forms an air cushion between the molded part 8 and the adjacent storage cell 2.

[0025] In Fig. 3 shows a pocket width of 14 and a pocket height of 15. The corresponding depth of pocket 10 is measured perpendicular to the pocket width of 14 and pocket height of 15. Fig. 2 shows a memory cell width of 16 and a memory cell height of 17.

[0026] The pocket width 14 and the pocket height 15 result in an area of ​​the pocket 10. The storage cell width 16 and the storage cell height 17 result in an area of ​​the storage cell front surface 6. The area of ​​the pocket 10 is preferably 10 to 90% of the area of ​​the storage cell front surface 6. This provides sufficient thermal insulation on the one hand and also ensures stable transmission of the clamping force F on the other. List of reference symbols 1 energy storage module 2 memory cells 3 end plates 4 Tension element, designed as a tension anchor 5 connection poles 6 Facing memory cell front surface 7 Memory cell side surface 8 molded part 9 row 10 bags 11 First molded part surface 12 Second molded part surface 13 side wings 14 pocket width 15 pocket height 16 memory cell width 17 memory cell height F clamping force

Claims

[1] Energy storage module (1) for a device for supplying voltage, in particular of a motor vehicle, comprising - several prismatic memory cells (2) which are stacked in at least one row (9) and arranged one behind the other, - two end plates (3) and at least one tension element (4), wherein the at least one row (9) of stacked storage cells (2) is clamped between the two end plates (3) via the tension element (4), and - at least one thermally insulating molded part (8) between one of the end plates (3) and the storage cell (2) adjacent to the end plate (3), wherein at least one pocket (10) is formed in a molded part surface (11) of the molded part (8) facing the adjacent storage cell (2), so that the adjacent storage cell (2) does not lie fully against the molded part (8). [2] Energy storage module according to claim 1, characterized bythat the molded part (8) is plate-shaped, with a first side against which the end plate (3) rests, and with a second side opposite the first side against which the adjacent storage cell (2) rests. [3] Energy storage module according to one of the preceding claims, characterized by that a memory cell front surface (6) facing the end plate (3) is a side of the memory cell (2) with the largest surface. [4] Energy storage module according to claim 3, characterized by that the memory cell front surface (6) facing the end plate (3) is a flat surface. [5] Energy storage module according to one of the preceding claims 3 or 4, characterized by that the molded part (8) extends over the entire storage cell front surface (6) facing the end plate. [6] Energy storage module according to one of the preceding claims 3 to 5, characterized bythat 10% to 90%, preferably 30% to 70%, of the storage cell front surface (6) facing the end plate (3) lies directly on the molded part (8) over its entire surface and the remaining portion of the storage cell front surface (6) facing the end plate (3) is spaced from the molded part (8) by the at least one pocket (10). [7] Energy storage module according to one of the preceding claims, characterized by that the molded part (8) has a wall thickness between 1 mm and 5 mm. [8] Energy storage module according to one of the preceding claims, characterized by that the depth of the pocket (10) is between 0.5 mm and 3 mm. [9] Energy storage module according to one of the preceding claims, characterized by that the molded part (8) at least partially covers at least one storage cell side surface (7) of the adjacent storage cell (2), wherein the storage cell side surface (7) is angled towards the storage cell front surface (6) facing the end plate (3). [10] Energy storage module according to one of the preceding claims, characterized by that the molded part (8) is manufactured in one piece, in particular as an injection-molded part.

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