Battery Cell Insulation and Cooling Unit

Abstract

The present invention relates to an insulation and cooling unit for at least one battery cell, having at least one cooling plate comprising a first main surface for thermal contact with at least one battery cell, a first end face and a second end face on the opposite side, and an insulating element for electrical insulation at the first end face of the cooling plate, wherein a first side surface of the insulating element is substantially in the same plane as the first main surface of the cooling plate.

Description

Technical Field

[0001] The present invention relates to an insulation and cooling unit for battery cells, and in particular to a battery cell unit with an insulation and cooling unit, which is used for traction batteries.

Background Art

[0002] In many technical fields, the concept of a battery is also recognized for accumulators and is used in the same way in the present application. This is particularly effective in applications in vehicles and aircraft, such as motor vehicles or rail vehicles with prime movers.

[0003] In vehicles and aircraft, traction batteries are used, and the traction batteries need to be cooled to ensure their performance and sufficient service life. For the battery cells of such batteries, various structures are known, especially prismatic, circular and pouch cells. For cooling, when the performance requirements are high, mainly water-cooled cooling plates made of aluminum alloy are used. Through the series connection of battery cells, the required voltage is achieved, and this voltage is in the kV range in traction batteries. For the cooling system, correspondingly good insulation needs to be ensured, because if it is not done, it will lead to short circuits and damage of the battery. Furthermore, a compact and lightweight structure of the traction battery is required, and at the same time, high mechanical and environment-related requirements over a long service life need to be met.

[0004] Ensuring reliable insulation of the battery cells from the cooling plate is also difficult in a structure that is as compact as possible, because when leakage current occurs through air and leakage paths, it is difficult to access the related system components. Furthermore, the insulation properties of materials are, from a physical point of view, in a position opposite to mechanical flexibility and good heat conduction, where the heat conduction is necessary to transfer the heat of the battery cells to the cooling plate.

[0005] It is known to attach a thin insulating film, such as Kapton or polyester, onto a battery cell. However, due to these materials being very mechanically delicate and thin, there is a risk of partial discharge. At corners and edges, insulation is often insufficient. The same applies to silicon-based films with or without glass fiber reinforcement. Certainly, depending on the hardness of the material used, tolerance compensation (i.e., adjustment of manufacturing tolerances in battery components) is possible, but it is also difficult to apply the material across corners and edges, and the edges of the heat insulation section are important with respect to air and leakage paths.

[0006] It is also possible to apply an insulating paint to the cooling plate. In this case, it is difficult to ensure good adhesion on the surface over a long period, and there is also a risk of cracking, perforation, or peeling at corners, edges, and holes. Tolerance compensation is not possible.

[0007] Finally, it is also known to achieve only low-voltage insulation in the battery area and high-voltage insulation at another location, for example, between the primary structure and the chassis of a vehicle. However, this leads to a costly structure because both the coolant and the connection point (primary structure to the vehicle's chassis) must be highly insulated over a long period and under all conditions. As a result, sufficient insulation is often not achievable. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0008] An object of the present invention is to provide a cooling unit for a battery cell that enables reliable insulation and good cooling at the same time. MEANS FOR SOLVING THE PROBLEM

[0009] This problem is solved by an insulation and cooling unit and by a battery cell unit having each feature of the independent claims. Advantageous forms of the invention are indicated in each of the dependent claims.

[0010] A first aspect of the invention is an insulation and cooling unit for at least one battery cell, comprising at least one cooling plate having a first main surface for thermal contact with at least one battery cell, a first end face, and a second end face opposite thereto, and an insulating element for electrical insulation at the first end face of the cooling plate, wherein a first side surface of the insulating element is substantially coplanar with the first main surface of the cooling plate.

[0011] The invention assumes that an insulating element is provided in contact with the first end face of the cooling plate, and a side surface of the insulating element is substantially coplanar with a side surface of the cooling plate. The side surface of the cooling plate is provided for thermal contact with the battery cell and is shown as the first main surface. The insulating element thus extends the first main surface of the cooling plate beyond its first end face. Since the end faces are substantially coplanar, there is a substantially flat base for the insulating layer, whereby the insulating layer does not need to go around edge portions or corner portions. Possible leakage paths to the cooling plate are clearly enlarged, and thereby the insulation performance is improved. The concept of the cooling plate includes various forms of cooling devices and does not only indicate a plate-like structure in a narrow sense, and in particular the side surfaces do not necessarily have to be flat. Advantageously, a coolant such as water flows through the cooling plate.

[0012] A second aspect of the invention is a battery cell unit comprising at least one battery cell and an insulation and cooling unit according to the invention, wherein a first main surface of the battery cell is in thermal contact with the first main surface of a cooling plate (4), and an insulating layer is arranged between these first main surfaces, the insulating layer extending substantially over the entire first main surface of the cooling plate and substantially over the entire first side surface of the insulating element.

[0013] The present invention also includes, thereby, one or more battery cells, and a battery cell unit having an insulation and cooling unit. In this case, the first main surface of the battery cell is in thermal contact with the first main surface of the insulation and cooling unit. An insulation layer is disposed between the first main surface of the cooling plate and the first main surface of the battery cell, and the insulation layer has sufficient thermal conductivity and at the same time sufficient electrical insulation properties. The insulation layer extends substantially over the entire first main surface of the cooling plate and at least a part of the first side surface of the insulation element. Due to the side surface of the cooling plate and the insulation element being substantially on the same plane, the insulation layer is provided in a planar manner, which is simple in manufacturing technology and reduces the risk of weak parts or breakage. Further, a certain tolerance compensation may be performed.

[0014] The battery cell may have a general structural type. In particular, it may be a prismatic cell, a pouch cell, or a circular cell.

[0015] According to an embodiment, the first end face of the battery cell is substantially flush with the first end face of the cooling plate. In other words, this part is at the "same height", and the heat insulation element protrudes therefrom. Alternatively, the first end face of the cooling plate may be at a higher or lower position than the end face of the battery cell. In the former case (a larger cooling plate), the cooling is improved. In the case of a smaller cooling plate, when the first end face of the cooling plate is at a lower position than the end face of the battery cell, the required space can be reduced. For example, the surface of the insulation element not facing the cooling plate can be flush with the first end face of the battery cell, whereby the insulation element does not protrude from the battery cell, and a particularly compact arrangement is achieved.

[0016] Advantageously, the insulation layer covers the entire first side surface of the insulation element, but there may be a non-covered part if sufficient insulation is ensured in the region of the first end face of the cooling plate.

[0017] The insulating element may be at least partially covered by an electrically insulated mounting element. The mounting element in particular serves to attach the insulating element to the cooling plate and / or to adequately fix the battery cell. The mounting element covers at least part of the battery cell, thereby achieving fixation in the corresponding direction. The mounting element may be connected to the insulating element, for example, by its shape, in particular, by a toothed shape or interlocking, or a screw connection may be provided.

[0018] The first end face of the cooling plate may be flat, but may also have a convex surface or a protrusion with an insulating element protruding therein. Thereby, the insulating effect is improved.

[0019] There may be a further insulating element in contact with the second end face on the opposite side of the first end face of the cooling plate. The first side face of the insulating element is likewise substantially in the same plane as the first main face of the cooling plate. That is, an equally advantageous effect occurs here. This is because the insulating layer is provided on a substantially smooth surface, so there is no need to wind the insulating layer around corners or edges, which is unnecessary for good insulation. Even if there is some deviation from a completely smooth surface due to manufacturing tolerances, the insulating layer can make the necessary adjustments.

[0020] For the further insulating element, basically the same type as the insulating element is possible. It is particularly suitable if the further insulating element also constitutes a holder or support for the battery cell or for the adjacent battery cell here. Depending on the arrangement of the battery cells, the battery cell adjacent to the further insulating element may be a battery cell different from the battery cell adjacent to the insulating element. The further insulating element may have a T-shaped or angled cross-section and may extend at least partially below the adjacent battery cell. Furthermore, the second end face of the cooling plate may have a convex surface or a protrusion as described in relation to the first end face.

[0021] Generally, a plurality of battery cells, hereinafter referred to as modules, are arranged between two insulation and cooling units, interconnected in a desired manner, and generate the required voltage and current. The geometric arrangement of the battery cells in the module depends on the structural type of the battery cells. Advantageously, a plurality of such modules are arranged adjacent to each other, and between each two modules, there is an insulation and cooling unit. These so-called inner insulation and cooling units also have an insulation layer on the second main surface opposite to the first main surface. Advantageously, the inner insulation and cooling units are symmetrically configured.

[0022] There may be a heat conduction structure between some or all of the battery cells of the module. The heat conduction structure advantageously has thermal conductivity and electrical conductivity, and the electrical conductivity may particularly play a role in connecting the battery cells.

[0023] Particularly advantageously, the battery cell unit is configured as a traction battery for a vehicle, particularly a rail vehicle.

[0024] The present invention will be described in more detail by the following examples.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

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Figure 10

Embodiments for Carrying Out the Invention

[0026] Although cross-sections are shown in the figures, for clarity, the internal structures of each component, such as the cooling plate and the battery cell, are not shown.

[0027] FIG. 1 shows a battery cell unit 1 including an insulation and cooling unit 2 and a battery cell 3 in a first embodiment. The insulation and cooling unit 2 includes a cooling plate 4 having a first main surface 4a and a first end surface 4b. An insulating element 5 is disposed in contact with the first end surface 4b, and the insulating element has a first side surface 5a. The first side surface 5a and the first main surface 4a are in the same plane, thereby forming a continuous smooth installation surface for the insulating layer 6 here. The insulating layer 6 extends over the entire first main surface 4a of the cooling plate and the entire first side surface 5a of the insulating element. The battery cell 3 is electrically insulated through the insulating layer 6 of the cooling plate on its first main surface 3a, but is thermally connected. For the insulating layer, for example, a glass fiber-reinforced silicon material with a ceramic filler in the range of 0.1 mm to 5 mm in thickness for better thermal conductivity is used, or another material at the current technical level, such as Kapton or polyester, is used. Also, a combination of such a glass fiber-reinforced silicon material and a reticulated initial liquid silicon material is possible.

[0028] In this embodiment, the first end surface 3b of the battery cell is in the same plane as the first end surface 4b of the cooling plate. However, the first end surfaces 3b and 4b may also be in different planes.

[0029] Typically, a plurality of battery cells are connected in series front to back, i.e., on the front or back surface at the drawing level, and are connected as one module in an appropriate manner. And the insulation and cooling units correspondingly extend over the length of the module on the front and back surfaces at the drawing level. In this embodiment, prismatic battery cells are assumed.

[0030] Figure 2 shows an insulation and cooling unit comprising adjacently installed battery cell units with battery cells 3, 30, 31, and cooling plates 4, 40 and insulation elements 5, 50 therebetween. Here, an insulation layer 6 is installed or arranged on the first main surfaces 4a, 40a of the cooling plates and on the second main surfaces 4c, 40c on the opposite side. The insulation layers 6 may each have a greater length, and the lengths protruding beyond the first end faces 3b, 30b, 31b of the battery cells 3, 30, 31 respectively, or beyond the insulation elements 5, 50 respectively, may be distributed over adjacent battery cells or insulation elements. Also, even if damage occurs in this area, the leakage path is not thereby shortened. This is because the leakage path is continuously guaranteed by the insulation elements. In this embodiment, the surfaces 5b, 50b of the insulation elements 5, 50 on the side opposite to the cooling plates are placed on the same plane as the first end faces 3b, 30b, 31b of the battery cells. By having the same height, as a result, a particularly space-saving structure is achieved. Similarly, on the surface on the side opposite to the first end face 4b of the cooling plate, another insulation element is provided, i.e., the cooling plate 4 is correspondingly short, and it is significant that the another insulation element is placed on the same plane as the back side of the battery cell. Thereby, while achieving very reliable electrical insulation, at the same time, an overall very space-saving structure is obtained.

[0031] Figure 3 shows a third embodiment, in which the insulating element 5 is covered by an electrically insulated mounting element 7. The mounting element 7 also extends over the insulating layer 6 and the upper parts of the adjacent battery cells 3, 31. The battery cells are thus fixed. The fixing or support in opposite directions to each other is achieved by another insulating element 8 which abuts against a second end face 4d on the side opposite to the first end face of the cooling plate. This other insulating element 8 has a T-shaped cross-section and extends partly below the adjacent battery cells, i.e. below the second end faces 3c, 31c on the side opposite to the first end face 3a. The side faces of the other insulating element 8 are flush with the first or second main faces 4a, 4c of the insulating and cooling unit. In a variant, the other insulating element 8 may have a rectangular cross-section, i.e. it does not extend below the adjacent battery cells and does not serve for fixing or support. Advantageously, as already described in the description of FIG. 2, the other insulating element 8 is continuous with the second end faces 3c, 31c. The mounting element 7 may be connected to the insulating element 5 and optionally to the cooling plate, for example by a screw connection. The insulating element 5 and the mounting element 7 may also be formed to be connected to each other by interlocking. In the third embodiment, the insulation is also improved in the lower region of the battery cells by another insulating element 8. This is because the possible leakage paths are clearly extended. There, the lower insulating element is coated only by one insulating material, the core of which is composed of another material, for example a thermally conductive material, advantageously the material of the cooling plate.

[0032] Figure 4: In this embodiment, the first end face 4b of the cooling plate has a projection protruding into the insulating element 5. Thereby, the cooling plate 4 can be enlarged without substantially reducing the insulating effect.

[0033] Figure 5 shows the upper part of the insulating and cooling unit when the first or second main faces 4a, 4c of the cooling plate 4 and the corresponding side faces 5a of the insulating element 5 are not completely flush. The slight step that occurs can be compensated for by the insulating layer 6 if the insulating layer 6 selected is sufficiently plastic.

[0034] FIG. 6 shows an embodiment in which the insulating element 5 is continuous at the top with the first end faces 3b, 31b of the battery cells at a protrusion of the cooling plate 4 where another insulating element 8 protrudes therein. By this measure, a very good insulation and cooling effect is achieved while having a compact structure. It is also possible that the cooling plate further protrudes inside another insulating element and extends downward of the battery cell, and the other insulating element partially wraps the cooling plate here. This is advantageous for stability because the cooling plate 4 is usually made of a conductive metal. Wrapping in this way is preferably provided at locations where an extension of the leakage path is required. This can be, for example, the interface between the insulating element 8, the insulating layer 6, and the battery cells 3, 31.

[0035] FIGS. 7 and 8 show an embodiment including battery cells 3, 32, 33, 34, and FIG. 8 shows a cross-sectional view at the level indicated by the line in FIG. 7, that is, at the height of the insulating element 5. In FIG. 8, the battery cells 32, 33, 34 placed one behind the other can be recognized, and the battery cells are configured as pouch cells. For better heat removal, a heat conduction structure 9 is added, for example, every three cells, and the heat conduction structure extends to the insulating layer 6 on one side, the right side in FIG. 8, and can be connected here, thereby having a comb-shaped structure or a repeated L-shaped structure. The heat conduction structure 9 may extend to the insulating layer alternately on one side and the opposite side for each section, that is, the repeated L-shaped structures are stacked in mirror image with the structures below respectively. At the very front and very rear of the module, cover plates 10 are provided as the final parts. As long as the cover plate 10 is made of a conductive material, the cover plate needs to be additionally electrically insulated from the battery cell 32 or the heat conduction structure 9 in contact with each cover plate 10. For this purpose, plates or blocks of electrical insulating material may be provided, and according to the example of FIG. 8, they are arranged above the upper battery cell 32 or below the teeth of the lower heat conduction structure 9. Each of the plates or blocks has a thickness corresponding to the required extension of the leakage path.

[0036] Figures 9 and 10 are examples with circular cells, and Figure 10 shows a cross-sectional view at the level indicated by the line in Figure 9, that is, parallel and closely adjacent to the insulating layer 6. Battery cells 32, 33, 34 are arranged horizontally, and their poles are appropriately connected by a conductive heat conduction structure. In the example, as can be recognized in Figure 10, 14 cells are connected in a row. The heat conduction structure 9 further serves as a heat connection to the insulating layer 6 on both sides of the module. The cooling plate 4 is in contact with the boundary of the insulating element 5 and another insulating element 8. The first side surfaces 5a, 8a of the insulating elements 5, 8 and the first main surface 4a of the cooling plate are here on the same plane, so that the insulating layer 6 does not need to cover corners or edges.

[0037] The features and aspects of the present invention described in the examples can of course be combined with each other in different forms. In particular, the features can be used not only in the described combinations but also in other combinations or by themselves.

Explanation of reference numerals

[0038] 1 Battery cell unit 2 Insulation and cooling unit 3, 30, 31, 32, 33, 34 Battery cells 3a First main surface of the battery cell 3b First end surface of the battery cell 3c Second end surface of the battery cell 4, 40 Cooling plates 4a, 40a First main surface of the cooling plate 4b First end surface of the cooling plate 4c, 40c Second main surface of the cooling plate 4d Second end surface of the cooling plate 5 Insulating element 5a First side surface of the insulating element 5b Opposite side surface of the insulating element 6 Insulating layer 7 Mounting element 8 Another insulating element 8a First side of another insulating element 9 Heat conduction structure 10 Cover plate

Claims

1. An insulation and cooling unit (2) for at least two battery cells (3, 31), comprising at least: - a cooling plate (4) having a first main surface (4a) for thermal contact with a battery cell (3) and one of second main surfaces (4c, 40c) on the opposite side of the first main surface for thermal contact with a second battery cell (31), a first end face (4b) and a second end face (4d) on the opposite side; - an insulating element (5) for electrical insulation at the first end face (4b) of the cooling plate (4); characterized in that: - a first side surface (5a) of the insulating element (5) is substantially coplanar with the first main surface (4a, 40a) of the cooling plate. Insulation and cooling unit.

2. The insulation and cooling unit further has an insulating layer (6) for electrical insulation, and the insulating layer is installed on the first main surface (4a) of the cooling plate (4) and at least part of the first side surface (5a) of the insulating element (5). The insulation and cooling unit according to claim 1.

3. A battery cell unit (1) comprising at least one battery cell (3) and the insulation and cooling unit according to claim 2, characterized in that: - a first main surface (3a) of the battery cell (3) is in thermal contact with the first main surface (4a) of the cooling plate (4), and an insulating layer (6) is arranged between the first main surfaces (3a, 4a); - the insulating layer (6) extends substantially over the entire first main surface (4a) of the cooling plate (4) and at least part of the first side surface (5a) of the insulating element (5). Battery cell and battery cell unit (1).

4. The battery cell unit (1) according to claim 3, characterized in that a first end face (3b) of the battery cell (3) is substantially coplanar with the first end face (4b) of the cooling plate (4) or substantially coplanar with a surface (5b) of the insulating element (5) on the side opposite to the cooling plate (4).

5. The battery cell unit (1) according to claim 3 or 4, characterized in that the insulating element (5) is at least partially covered by an electrically insulated mounting element (7), and the insulated mounting element (7) fixes the battery cell (3).

6. The battery cell unit (1) according to any one of claims 3 to 5, characterized in that the first end face (4b) of the cooling plate (4) has a raised portion or a protrusion protruding into the interior of the insulating element (5).

7. The battery cell unit (1) according to any one of claims 3 to 6, characterized in that another insulating element (8) is arranged in contact with the second end face (4d) of the cooling plate (4), and the side face (8a) of the another insulating element (8) is placed substantially flush with the first main surface (4a, 40a) of the cooling plate (4).

8. The battery cell unit (1) according to claim 7, characterized in that the another insulating element (8) has a T-shaped or angled cross-section and extends at least partially below the second end face (3c) of the battery cell (3) on the side opposite to the first end face (3b).

9. The battery cell unit (1) according to claim 8, characterized in that the another insulating element (8) is made of a heat-conductive material and is at least partially coated with an insulating material for electrical insulation.

10. The battery cell unit (1) according to any one of claims 3 to 9, characterized in that a heat-conductive structure (9) is arranged between two battery cells (3, 30, 31, 32, 33, 34) and / or between the battery cell (3, 30, 31, 32, 33, 34) and the insulating layer (6).

11. The battery cell unit (1) according to any one of claims 3 to 10, characterized in that it is configured as a traction battery for a vehicle, in particular a rail vehicle.

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