Battery cell with internal cooling element and battery module comprising it

Abstract

Battery element with internal cooling element and battery module comprising it. The invention relates, in various embodiments, to a battery element (10) with an internal cooling element (6), comprising an internal space (5) in which electrochemically active components are arranged, the internal space (5) having an external wall (21, 22) on each of at least two sides, which are connected to each other by an internal wall (23); and the internal cooling element (6) which is arranged in the internal wall (23). Furthermore, the invention relates to a battery module with at least two of the battery elements (10). Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Battery element with internal cooling element and battery module comprising same

[0001] The present invention relates to a battery element with an internal cooling element. The invention also relates to a battery module comprising at least two battery elements according to the invention.

[0002] Battery cells must be cooled to achieve good service life and performance. This is particularly the case for battery cells in traction batteries for electric vehicles, which must be able to absorb and, in particular, deliver high power levels. A large contact surface between the battery cell to be cooled and the cooling medium and a low thermal resistance are important for good heat transfer. The thermal resistance increases with the distance and the number of insulating layers between the cooling medium and the heat generation source. In battery cells, the cooling is carried out outside the battery cell, so that there is a relatively large distance between the active part of the battery cell, in which the waste heat is generated, and a cooling plate, for example.

[0003] Document DE 102009034675 A1 discloses an electrochemical energy storage device with at least two electrical current limiters for electrically connecting the electrochemical energy storage device within an application environment. The current limiters have a first region arranged inside the electrochemical energy storage device and a second region arranged outside the electrochemical energy storage device, at least one of these electrical current limiters being designed such that a liquid or gaseous heat transfer medium can flow through it in the second region.

[0004] Publication EP 2659540 B1 discloses a battery comprising a battery box having at least one open end; a battery cover sealing the open end; an electric core housed in the battery box and comprising at least one thermally conductive member, the thermally conductive member having at least one end passing through the battery cover; and an electrolyte which is charged in a space formed by the battery box with the battery cover.

[0005] Publication EP 2659540 B1 discloses an electrical energy storage element for a motor vehicle with a housing that defines an interior space in which electrochemical components of the energy storage element are housed, and with a conduit passing through the interior space, through which a cooling or heating medium can be conducted through the interior space.

[0006] On this basis, the task of the present invention may be to provide an efficient and at the same time cooling concept for a battery cell and a battery module based thereon, which also involves as little additional weight as possible.

[0007] This problem is solved by the invention by means of a battery element having an internal cooling element, comprising: - an interior space in which electrochemically active components are arranged, the interior space comprising on at least two sides a respective outer wall, which are connected to each other by an inner wall; - the internal cooling element, which is arranged in the inner wall.

[0008] The invention relates to a battery cell with an internal cooling element, having an interior space in which electrochemically active components are arranged, the interior space having an outer wall on or on at least two sides, which are connected to each other by an inner wall. The battery also comprises the internal cooling element, which is arranged in the inner wall. The electrochemically active components can be the chemical substances and elements required for energy storage in batteries. In principle, the battery cell described here can be of different types, for example, a lithium-ion battery.In such a case, the electrochemically active components may, for example, comprise a graphite electrode (negative) and a lithium metal oxide electrode (positive), wherein the lithium metal oxide may comprise different proportions of nickel, manganese and cobalt. However, the battery cell according to the invention does not depend on a specific chemical formulation or type of battery cell, but can be used in combination with different chemical formulations of battery cell.

[0009] As regards the design, the battery element according to the invention described here may correspond to a pouch element. In principle, the battery element according to the invention may be an accumulator element or a battery element of an accumulator or a battery, in particular of a traction battery of an electric vehicle.

[0010] In the battery cell according to the invention, the cooling element, which may comprise at least one cooling plate, for example, is integrated directly into the battery cell, i.e. into its interior. A refrigerant can flow through the cooling element to cool the battery cell. This results in a very small distance between the components electrochemically active inside the battery cell and the cooling element, which allows for very good heat transfer from the electrochemically active components to the refrigerant.

[0011] The at least two outer walls may be, for example, opposing outer walls, such as the end faces of a substantially cuboidal battery cell, wherein at least some of the edges of the surrounding envelope may be rounded.

[0012] The outer walls and the inner wall may be connected to each other in a structurally stable manner, i.e. form a mechanically stable framework around which, for example, an electrically insulating jacket may be tensioned or wound. In other words, the inner wall may be a load-bearing or supporting wall or structure that transmits forces acting on the at least one outer wall to the at least one further outer wall. The internal cooling element may thus have an additional stiffening effect on the battery cell and may protect the battery cell from deformation during assembly of a corresponding battery module, during operation or in the event of damage. The internal cooling element may, therefore, be characterized by being surrounded by the active material on at least two sides.If necessary, the internal cooling element can divide the interior space of the battery cell into two compartments.

[0013] According to further embodiments of the battery element according to the invention, the battery element may further comprise a refrigerant inlet and a refrigerant outlet, which may be arranged on at least one outer side of the battery element and are provided to form a refrigerant flow through the cooling element. In principle, the refrigerant inlet and outlet may be arranged on one side of the cooling element or on an outer wall, or equally well on different outer walls.

[0014] According to other embodiments of the battery cell according to the invention, the inner wall may be arranged centrally within the battery cell. The inner wall may have a sinuous or zigzag shape in order to increase the contact surface between the inner wall and the chemically active components compared to a plate-type embodiment in which the inner wall has substantially planar surfaces.

[0015] According to other embodiments of the battery element according to the invention, the at least two external walls and the internal wall connecting them can form an H-shaped structure.

[0016] According to other embodiments of the battery element according to the invention, the electrochemically active components may comprise an active material.

[0017] According to other embodiments of the battery element according to the invention, the internal wall can be arranged in a neutral fiber of the active material.

[0018] According to other embodiments of the battery cell according to the invention, the latter may be enclosed in an electrically insulating material, which represents an envelope of the battery cell and may be understood as a "soft" housing (compared to the "rigid" housing of conventional battery cells). The outer walls, which are firmly connected to each other via the inner wall, serve as a clamping structure for the insulating material, for example, a film, which may also serve to protect the battery cell.

[0019] The invention also provides a battery module which comprises at least two battery cells as described above, which are connected to each other in series or in parallel.

[0020] In one embodiment, the battery cell according to the invention may correspond to a "turned-over" pouch cell. Until now, a rigid housing was constructed around the active material in conventional pouch cells, and then a cooling plate or cooling structure was attached to the outside of the battery cell. In the present invention, a part of the structural housing, for example two opposing outer walls, is placed towards the interior space, preferably centrally between the active material. In addition, the cooling structure is integrated or arranged in this inner wall, which may then be in the neutral fiber of the active material, for example. The cooling structure is used to dissipate heat to the outside, for example, a cooling agent may flow through it during operation.Cooling / heat dissipation then advantageously takes place over the entire surface of the core of the active material, for example along the median plane of the volume of active material.

[0021] It is understood that the above-mentioned features and the features which will be explained below can be used not only in the combination respectively specified, but also in other combinations, or alone, without departing from the scope of the present invention.

[0022] Other advantages and configurations of the invention will emerge from the description and the accompanying drawings.

[0023] [Fig. 1] shows a schematic sectional view of an ordinary battery cell.

[0024] [Fig.2] represents a schematic sectional view of an exemplary mode of production of the battery element according to the invention.

[0025] [Fig.3] represents a perspective view of an exemplary embodiment of the battery element according to the invention.

[0026] [Fig.l] shows a schematic sectional view of an ordinary battery cell 1. This has a usually rigid or stiffening casing 2 in which the active material 3 is arranged. To protect the battery element 1, the latter is sealed by an electrically insulating material 4. For cooling purposes, a cooling plate or a cooling structure is attached to the battery element 1 from the outside (not explicitly shown in [Fig.l]).

[0027] [Fig. 2] shows a schematic sectional view of an exemplary embodiment of the battery cell 10 according to the invention. In contrast to the conventional battery cell 1 shown in [Fig. 1], there is no surrounding stable housing 2 here. The exemplary embodiment of the battery cell 10 shown in [Fig. 2] has an interior space 5 in which electrochemically active components are arranged, the interior space 5 having an outer wall on each of at least two sides, in the exemplary embodiment shown a first outer wall 21 and a second outer wall 22, which are connected to each other by an inner wall 23.

[0028] Furthermore, the battery cell 10 has an internal cooling element 6, which is arranged in the inner wall 23. In the exemplary embodiment shown, the cooling element 6 is in the form of cooling ducts passing through the inner wall, the direction of the cooling ducts 6 being perpendicular to the plane of the sheet.

[0029] The number and shape of the cooling ducts forming the cooling element 6 can be adapted as required. The layout of the cooling ducts in the inner wall, for example whether each cooling duct extends between an inlet and an outlet or has several 180° deflections between the inlet and the outlet, is also a matter of design of the cooling concept and can be adapted as required. For example, only one cooling duct can be provided in the inner wall 23. Regardless of the exact structure of the cooling element 6, the outer walls of the cooling element 6 also form the inner wall 23 passing through the interior space 5.

[0030] As in the case of the conventional battery cell 1 shown in [Fig.l], the battery cell 10 according to the invention is also sealed by an electrically insulating material 4. In other embodiments, the electrically insulating material 4 may only be wound along the casing of the battery cell 10, so that the end faces are exposed, for example. The end faces may be made of a material that is electrically insulating. It should also be noted that the connection electrodes of the battery cell 10 are not shown explicitly, since they play a subordinate role from the point of view of the invention.

[0031] [Fig. 3] shows a perspective view of the exemplary embodiment of the battery cell 10. The outer casing of the battery cell 10 is formed by the first outer wall 21 and the second outer wall 22 opposite it. In this exemplary embodiment, the outer casing of the battery cell 10 is also formed by a third outer wall 24, a fourth outer wall 25, a fifth outer wall 26 and a sixth outer wall 27, each of which is arranged in pairs opposite each other. The six outer walls 21 to 27 are all connected to each other and form a box-shaped casing for the battery cell.The inner wall is arranged inside the battery cell 10 such that a coolant can flow into the cooling element 6 through the inlet 7, flow through the cooling element into the battery cell 10, and then flow out of the cooling element through the outlet 8. In a modified exemplary embodiment of the battery cell 10, the coolant inlet 7 and the coolant outlet 8 may be arranged on different, in particular opposite, outer walls of the battery cell 10. For example, the coolant inlet 7 or the coolant outlet of [Fig. 3] may equally well be arranged on the fourth outer wall 25.

[0032] Of course, the invention is not limited to the embodiment described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. Battery cell (10) having an internal cooling element (6), comprising: an interior space (5) in which electrochemically active components are arranged, the interior space (5) comprising on at least two sides a respective outer wall (21, 22), which are connected to each other by an inner wall (23); the internal cooling element (6), which is arranged in the inner wall (23).

2. The battery cell (10) of claim 1, further comprising: a refrigerant inlet (7) and a refrigerant outlet (8), which are arranged on at least one outer side of the battery cell (10) and are provided to form a refrigerant flow through the cooling element (6).

3. A battery cell (10) according to claim 1 or 2, wherein the inner wall (23) is arranged centrally in the interior space (5).

4. Battery cell (10) according to one of claims 1 to 3, wherein the at least two outer walls (21, 22) and the inner wall (23) connecting them form an H-shaped structure.

5. A battery cell (10) according to one of claims 1 to 4, wherein the electrochemically active components comprise an active material.

6. A battery cell (10) according to claim 5, wherein the inner wall (23) is arranged in a neutral fiber of the active material.

7. A battery cell (10) according to one of claims 1 to 6, wherein the battery cell (10) is enclosed in an electrically insulating material (4).

8. Battery module comprising at least two battery cells (10) according to one of claims 1 to 7, which are connected to each other in series or in parallel.

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