Battery cell

Abstract

The invention relates to a battery cell comprising a first electrode arrangement and a second electrode arrangement and a separating element (37), wherein the separating element (37) is arranged between the first electrode arrangement and the second electrode arrangement. According to the invention, the porous and / or compressible separating element (37) is designed and / or suitable for being reversibly compressed in its thickness direction when the first electrode arrangement and / or the second electrode arrangement expands and / or increases in volume.

Description

[0001] The invention relates to a battery cell according to the preamble of claim 1.

[0002] A battery cell of this type is known from EP 2 742 551 B1. The battery cell has an interior housing that is bounded externally by the cell casing. An electrode stack with several electrodes is arranged within this interior housing. A pocket-shaped separating element made of a glass fiber fleece is slid over one electrode of the electrode stack, thereby optimizing the ion conductivity within the housing. When the battery cell is charged, the electrode stack expands primarily in its thickness direction, causing the cell casing to bulge outwards and the battery cell to occupy more space. The battery cell thus has the disadvantage of requiring a large amount of space during operation.

[0003] One object of the invention is to provide a battery cell that can be operated with a smaller installation space requirement compared to the known battery cell.

[0004] This problem is solved by the features of the independent claim. Preferred embodiments of the invention are disclosed in the dependent claims.

[0005] The invention proposes a battery cell comprising a first electrode arrangement, a second electrode arrangement, and a separating element, the separating element being arranged between the first and second electrode arrangements. The invention provides that the porous and / or compressible separating element is designed and / or suitable for reversibly compressing in its thickness direction when the first and / or, preferably, the second electrode arrangement expands and / or increases in volume, preferably in the thickness direction. Because the separating element compensates for the expansion of the electrode arrangements, also referred to as swelling, within the interior of an enclosure enclosed by the battery cell, the space required by the battery cell remains unchanged during operation.The battery cell therefore requires less space during operation and compared to conventional battery cells. This simplifies the packaging of the battery cell, especially when assembling it with other battery cells to form a battery cell array or a battery.

[0006] Furthermore, the use of the separating element allows the cell intermediate element between the battery cell and an adjacent battery cell to be significantly thinner and / or, for example, incompressible, since the cell intermediate element does not have to absorb any forces caused by the expansion of the electrode arrangements.

[0007] For example, it is provided that the first electrode arrangement is formed by a cell stack or a cell coil, and / or that the second electrode arrangement is formed by a cell stack or a cell coil.

[0008] In the case of more than two electrode arrangements, the battery cell can have two or more, preferably identical, separating elements, wherein it is preferably provided that exactly one of the separating elements is arranged between each pair of adjacent electrode arrangements.

[0009] In order to manufacture and assemble the electrode arrangements of the battery cell independently of the separating element, in an exemplary embodiment, preferably in which the first electrode arrangement and / or the second electrode arrangement is each formed by a cell winding, it is provided that the separating element neither projects into nor is integrated into the first electrode arrangement or the second electrode arrangement, and / or that the separating element is arranged completely between a first electrode of the first electrode arrangement and a second electrode of the second electrode arrangement.

[0010] Preferably, the first electrode is part of the first electrode arrangement, and / or the second electrode is part of the second electrode arrangement.

[0011] It is particularly preferred that the separating element is in direct contact with only exactly two electrodes, namely exclusively with an electrode of the first electrode arrangement and a second electrode of the second electrode arrangement, and / or that the separating element does not surround either of the electrodes of the first electrode arrangement and / or the second electrode arrangement.

[0012] In order to manufacture the battery cell in a space-saving manner and with high energy density, an exemplary embodiment provides that the battery cell has a housing and an interior of the housing which is bounded externally by the housing, wherein the battery cell has an electrolyte which is arranged in the interior of the housing together with the first electrode arrangement and the second electrode arrangement and the separating element, and wherein the separating element is at least partially wetted with the electrolyte and / or the electrolyte is at least partially absorbed by the separating element.

[0013] For example, the battery cell is a pouch battery cell, and / or the housing is formed by a pouch, preferably made of plastic. Alternatively or additionally, for example, the battery cell is a prismatic battery cell, and / or the housing is formed by a cuboid cell casing.

[0014] For example, it is provided that the electrolyte comprises lithium hexafluorophosphate as the conducting salt, preferably together with cyclic carbonates and / or acyclic carbonates, and / or that the electrolyte is free of SO2, and / or that the electrolyte contains so little SO2 that charge transport between electrodes of the first electrode arrangement and / or the second electrode arrangement is not caused by SO2.

[0015] In order to manufacture the separating element cost-effectively, in an exemplary embodiment it is provided that the separating element is formed by a textile surface structure, preferably by a nonwoven fabric, or by a foam, preferably by a polyurethane foam.

[0016] In order to compensate for a relatively larger extent of the first electrode arrangement and / or the second electrode arrangement by means of the separating element, an exemplary embodiment provides that the separating element has a thickness, wherein it is provided that the thickness has a basic value in the mechanically unloaded state of the separating element, and wherein it is provided that the separating element is designed and / or suitable to be compressible in the thickness direction to 55% or to more than 55% of the basic value.

[0017] In order to compensate for a relatively larger extent of the first electrode arrangement and / or the second electrode arrangement by means of the separating element, a preferred embodiment provides that the separating element has a thickness, wherein the thickness has a base value of 110 µm in the mechanically unloaded state of the separating element, and wherein the thickness has a first value of 92 µm under a pressure load of 50 kPa, and / or wherein the thickness has a second value of 55 µm under a pressure load of 500 kPa.

[0018] The textile fabric, preferably the nonwoven, can be porous and / or compressible. The foam, preferably polyurethane foam, can be porous and / or compressible.

[0019] Preferably, the separating element is cuboid and / or plate-shaped, at least in a mechanically unloaded state.

[0020] In order to manufacture the battery cell with the highest possible energy density, in an exemplary embodiment it is provided that the opposing electrodes of the first electrode arrangement and the second electrode arrangement are each separated by a separator of the battery cell, preferably electrically insulated from each other, wherein it is provided that the separators each have a thickness with a thickness value in the range of 10 µm to 15 µm.

[0021] The invention further proposes a battery cell arrangement, preferably a battery, comprising a first battery cell as described above and a second battery cell as described above and / or identical in construction to the first battery cell, wherein the battery cell arrangement includes an intermediate cell element, the intermediate cell element being arranged between the first battery cell and the second battery cell. Because each of the battery cells is space-saving during operation, the battery cell arrangement or battery can be manufactured with a higher energy density.

[0022] In order to achieve flame and / or heat propagation, a so-called thermal propagation, within the battery cell arrangement in the most efficient way possible by means of the cell inter-element, an exemplary embodiment provides that the, preferably plate-shaped, cell inter-element and / or the material of the cell inter-element has a mechanically higher stiffness and / or is incompressible and / or rigid compared to the separating element.

[0023] The following are descriptions of embodiments of the invention with reference to the accompanying figures.

[0024] They show: Fig. 1 in a partial sectional view from above a battery cell arrangement, and Fig. 2 in a partial sectional view from above another battery cell arrangement.

[0025] In the Fig. Figure 1 shows a battery cell arrangement 1. The battery cell arrangement 1 comprises a battery cell 11 and a battery cell 21. The battery cell 11 is located in the Fig. 1 is shown in a cross-sectional view from above, whereas battery cell 21 is only shown in a top view.

[0026] Battery cell 11, shown here only as an example, is a prismatic battery cell. Battery cell 11 has an internal housing and a dimensionally stable enclosure 31 that forms the external boundary of the internal housing. Furthermore, battery cell 11 has a first electrode arrangement with several electrodes, formed by a cell winding 33, and a second electrode arrangement with several electrodes, formed by a cell winding 35. Battery cell 11 also has a separating element 37, which, together with the first electrode arrangement 33, the second electrode arrangement 35, and an electrolyte (not shown) of battery cell 11, is arranged within the internal housing. The electrolyte consists of lithium hexafluorophosphate with cyclic and / or acyclic carbonates as the conducting salt. Ideally, the electrolyte is free of SO2.At the very least, the electrolyte contains so little SO2 that charge transport between the electrodes of the first electrode arrangement and the second electrode arrangement is essentially not caused by SO2.

[0027] The opposing electrodes of the electrode arrangements are each electrically isolated from each other by separators 39 of battery cell 1. The separators 39 are only present in the Fig. 2 indicated, however in the Fig. 1 not shown. The separators 39 each have a thickness parallel to a transverse axis Q of the battery cell 1 with a thickness value in the range of 10 µm to 15 µm.

[0028] The separating element 37 is arranged between the first electrode arrangement and the second electrode arrangement. The separating element 37 is, for illustrative purposes only, plate-shaped. The separating element 37 does not project into either the first or the second electrode arrangement and is completely positioned between an electrode of the first electrode arrangement and an electrode of the second electrode arrangement. A first side surface of the separating element 37 is in planar contact with an electrode of the first electrode arrangement, and a second side surface of the separating element 37, opposite the first side surface, is in planar contact with a second electrode of the second electrode arrangement.

[0029] The separating element 37, shown here only as an example, is reversibly compressible and formed by a textile fabric in the form of a nonwoven. When the first electrode arrangement and the second electrode arrangement expand or increase in volume, primarily along the transverse axis Q, the separating element 37 is reversibly compressed in its thickness direction, i.e., parallel to the transverse axis Q. The separating element 37 has a thickness D in the thickness direction. The thickness direction is in the Fig. 1 and Fig. 2 is indicated by a double arrow 41 and extends parallel to the transverse axis Q. In the mechanically unloaded state of the separating element 37, i.e., primarily when the battery cell 11 is electrically uncharged, the thickness has a base value of 110 µm. The separating element 37, specifically the material of the separating element 37, is selected such that the separating element 37 is compressible in the thickness direction to 55% or more than 55% of the base value. At a pressure load of 50 kPa, the separating element 37 has a thickness with a first value of 92 µm. At a pressure load of 500 kPa, the separating element 37 has a thickness with a second value of 55 µm. The separating element 37, specifically the material of the separating element 37, is wetted with the electrolyte, and the electrolyte is at least partially absorbed by the separating element 37.

[0030] A plate-shaped cell interelement 51 is arranged between battery cell 11 and battery cell 21. The cell interelement 51, specifically its material, is incompressible or at least less compressible than the material of the separating element 37. Thus, in battery cell 11, there is a functional separation between the separating element 37 and the cell interelement 51, whereby the expansion of the first and second electrode arrangements along the thickness direction during operation of battery cell 11 is efficiently compensated solely by the separating element 37. Conversely, the cell interelement 51 is designed to prevent any potential flame and / or heat propagation, a so-called thermal propagation, between battery cells 11 and 21 as efficiently as possible.

[0031] Battery cell 21 is identical to battery cell 11. The previously mentioned characteristics and properties for battery cell 11 therefore also apply without restriction to battery cell 21.

[0032] In the Fig.Figure 2 shows a battery cell arrangement 101. Elements of the battery cell arrangement 101 that are structurally and functionally identical to the elements of the battery cell arrangement 1 are designated with the same reference numerals. The battery cell arrangement 101 comprises a battery cell 111 and a battery cell 121 that is structurally identical to battery cell 111. Battery cell 111 is essentially identical to battery cell 11 and differs from battery cell 11 only in that the first electrode arrangement of battery cell 111 is formed by an electrode stack 131, and that the second electrode arrangement of battery cell 111 is formed by an electrode stack 133. Battery cell arrangement 111 is otherwise identical to battery cell arrangement 1. The electrodes of electrode stack 131 and electrode stack 133 are stacked one behind the other along the transverse axis Q of battery cell 111.

[0033] In this or another embodiment of the battery cells 1 or 101, the separating element 37 can also be formed, for example, by a porous and / or compressible foam, preferably by a polyurethane foam.

[0034] The battery cell arrangement 1 or 101 can each be part of a battery comprising a battery housing and a battery housing interior, which is bounded externally by the battery housing. Within the battery housing interior, the battery cell arrangement 1 or 101 can be arranged together with the cell intermediate element 51. Reference symbol list 1 Battery cell arrangement 11 battery cell 21 battery cells 31 Enclosure 33 Electrode arrangement 35 Electrode arrangement 37 Separating element 39 Separator 41 Double Arrow 51 Cell interelement 101 Battery cell arrangement 111 Battery cell 121 battery cells 131 electrode stacks 133 electrode stacks Q transverse axis QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 742 551 B1

[0002]

Claims

[1] Battery cell with: a first electrode arrangement, a second electrode arrangement, and a separating element (37), wherein the separating element (37) is arranged between the first electrode arrangement and the second electrode arrangement, characterized by , that the porous and / or compressible separating element (37) is designed and / or suitable to be reversibly compressed in its thickness direction when the first electrode arrangement and / or the second electrode arrangement expands and / or increases in volume. [2] Battery cell according to claim 1, characterized by , that the separating element (37) neither projects into nor is integrated into the first electrode arrangement or the second electrode arrangement, and / or that the separating element (37) is completely arranged between a first electrode of the first electrode arrangement and a second electrode of the second electrode arrangement. [3] Battery cell according to claim 1 or 2, characterized by , that the battery cell (11; 21; 111; 121) has a housing (31) and an interior of the housing which is bounded externally by the housing (31), wherein the battery cell (11; 21; 111; 121) has an electrolyte which is arranged in the interior of the housing together with the first electrode arrangement and the second electrode arrangement and the separating element (37), and wherein the separating element (37) is at least partially wetted with the electrolyte and / or the electrolyte is at least partially absorbed by the separating element (37). [4] Battery cell according to claim 3, characterized by, that the electrolyte comprises lithium hexafluorophosphate as the conducting salt, preferably together with cyclic carbonates and / or acyclic carbonates, and / or that the electrolyte is free of SO2, and / or that the electrolyte contains so little SO2 that charge transport between electrodes of the first electrode arrangement and / or the second electrode arrangement is not caused by SO2. [5] Battery cell according to any one of the preceding claims, characterized by , that the separating element (37) is formed by a textile surface structure, preferably by a nonwoven fabric, or by a foam, preferably by a polyurethane foam. [6] Battery cell according to any one of the preceding claims, characterized by, that the separating element (37) has a thickness, wherein it is provided that the thickness has a basic value in the mechanically unloaded state of the separating element (37), and wherein it is provided that the separating element (37) is designed and / or suitable to be compressible in the thickness direction to 55% or to more than 55% of the basic value. [7] Battery cell according to any one of the preceding claims, characterized by , that the separating element (37) has a thickness, wherein it is provided that the thickness, in the mechanically unloaded state of the separating element (37), has a basic value, wherein it is provided that the basic value is 110 µm, and wherein it is provided that the separating element (37) has a thickness with a first value of 92 µm when subjected to a pressure load of 50 kPa, and / or wherein it is provided that the separating element (37) has a thickness with a second value of 55 µm when subjected to a pressure load of 500 kPa. [8] Battery cell according to any one of the preceding claims, characterized by , that the opposing electrodes of the first electrode arrangement and the second electrode arrangement are each separated by a separator (39) of the battery cell (11; 21; 111; 121), preferably electrically insulated from each other, wherein it is provided that the separators (39) each have a thickness with a thickness value in the range of 10 µm to 15 µm. [9] Battery cell arrangement with: a first battery cell (11; 111) according to one of the preceding claims, and a second battery cell (21; 121) according to one of the preceding claims, wherein the battery cell arrangement (1; 101) has a cell intermediate element (51), wherein the cell intermediate element (51) is arranged between the first battery cell (11; 111) and the second battery cell (21; 121), and wherein the cell intermediate element (51) is arranged between the first battery cell (11; 111) and the second battery cell (21; 121). [10] Battery cell arrangement according to claim 9, characterized by that the, preferably plate-shaped, cell inter-element (51) and / or the material of the cell inter-element (51) has a mechanically higher stiffness and / or is incompressible and / or rigid compared to the separating element (37).

Images