Integrated function separator, battery cell incorporating it, and manufacturing processes

Abstract

Integrated Function Separator, Battery Cell Incorporating It, and Manufacturing Methods. The present invention relates to a separator (1) for spatially and electrically separating electrodes (2, 3) in a battery cell, the separator (1) comprising: a housing for at least one galvanic cell including an anode (2) and a cathode (3); a conductive material structure for electrically connecting the anode (2) and the cathode (3) and for establishing external contact with said at least one galvanic cell; a channel system (5) for forming a flow of cooling fluid within the separator (1); wherein at least the housing for said at least one galvanic cell and the channel system are integrally incorporated within the separator (1). A battery cell based on the separator according to the invention is further provided, as well as methods for its manufacture.Figure to be published with the abbreviation: Fig. 1.

Description

Title of the invention: Integrated function separator, battery cell incorporating it and manufacturing methods

[0001] The present invention relates to a separator with integrated function which, due to its advantageous mechanical and functional properties, can in particular be used to make a traction battery in an electric vehicle.

[0002] Given the constant increase in the number of hybrid and especially electric vehicles, the traction battery plays a very important role as an energy storage device, as it significantly affects vehicle range. Prior art batteries consist of individual cells, such as cylindrical cells or prismatic hard-shell / pocket cells, which are grouped into cell modules or directly into battery systems. These battery systems consist of at least two individual cells. The cell modules are assembled into battery systems. These battery systems are then installed in the vehicle.

[0003] It is known that a battery cell comprises a cathode and an anode that are spatially separated by a separator. The separator thus performs the central function of spatial and therefore simultaneously electrical separation of the electrodes, thereby preventing electrical short circuits. The separator can, for example, take the form of a separator sheet between the anodic and cathodic electrodes. Alternatively, it is possible to use a separator intended for the entire cell, as is the case for the Z-fold separator in certain cell variants, or a separator made from a single piece, as is the case for the cylindrical cell.

[0004] In the case of Li-ion cells, which are highly valued and widely used today, the separator is in the form of a porous sheet composed of one or more layers of plastic films. The separator can also be made from or using (additional) ceramic components.

[0005] The present invention aims to provide a separator enabling the production of a compact and lightweight battery cell.

[0006] This objective is achieved primarily by the invention, thanks to a separator intended to spatially and electrically separate electrodes in a battery cell. This separator comprises a housing for at least one galvanic cell, which includes an anode and a cathode, as well as a conductive material structure intended to electrically connect the anode and the cathode and to establish contact with said at least one galvanic cell from the outside. The separator It further comprises a system of channels for forming a flow of cooling fluid into or through the separator. The separator according to the invention is characterized in that at least the housing for said at least one galvanic cell and the system of channels are integrally formed within the separator.

[0007] The separator according to the invention is a separator with an integrated function which, in addition to its function of protecting against electrical short circuits between anode(s) and cathode(s), ensures new functions due to their spatial separation, which will be described in more detail below.

[0008] The separator according to the invention can be manufactured using an additive manufacturing process, for example by 3D printing. In this case, the separator can be manufactured separately from said at least one galvanic cell, which is introduced subsequently. The separator can preferably be manufactured as part of the manufacturing of a corresponding battery cell around cathodes and anodes arranged in a corresponding manner, so that these are thus integrated / embedded in the separator during the manufacturing process.

[0009] According to various embodiments of the separator, the separator, or more precisely, the separator structure or separator cavity, may contain a material or substance that hardens in a delayed manner, thus allowing the separator to acquire its final strength. The hardening process may be induced by the passage of time or by heat. For example, the separator may only harden upon the initial commissioning of a corresponding battery cell and under the effect of the heat emitted by the electrodes. In particular, the hardening process may be irreversible, thus enabling the mechanical strength to be achieved in the final three-dimensional shape of the separator.The delayed curing process can, for example, take place over a short timescale, chosen so that the final strength is reached very quickly, allowing the next layer of material to be applied directly to form the separator structure, for example, during the additive manufacturing process. However, the delayed curing process can also take place over a longer timescale, chosen so that the separator can be manufactured and is first sufficiently elastic to accommodate the electrodes of at least one galvanic cell. Generally, the viscosity of the material used to form the separator can be adjusted so that the separator structure does not bond to the anodic and cathodic electrodes.

[0010] According to different embodiments of the separator, it may have a porosity that allows the transport of ions. The porosity may be present as property of the material used for the manufacture of the separator from the application, i.e. during the formation of the separator structure.

[0011] According to various embodiments of the separator, an evaporable solvent may be contained within it. Evaporation of the solvent, for example by means of heat treatment or UV radiation, also makes it possible to subsequently impart porosity to the structure of the separator. This applies to both liquid-based and solid-based electrolytes.

[0012] According to other embodiments of the separator, the channel system formed therein can be constituted by hollow molds arranged within the separator. In this case, the hollow molds can be inserted during the fabrication of the separator structure. After the separator structure has hardened, these molds can be dissolved using a solvent, thereby creating the molded channels / cooling systems.

[0013] In cases where the separator exhibits some porosity, the hollow molds may, for example, consist of two layers. The inner layer can be dissolved using a solvent. The outer layer remains in place, thus ensuring a seal. Alternatively, after the single-layer hollow mold has been dissolved by a solvent, a sealing agent can be introduced to seal the porous openings of the separator at the interface with the dissolved hollow mold. This makes it possible to form a channel system for a cooling system within the separator, which has few partial components with few interfaces and therefore few potential leakage points.

[0014] When using the separator according to the invention to manufacture a corresponding battery cell, it allows for the mechanical attachment of other components, such as electrodes / anode stacks, busbars, etc., to ensure mechanical stability in the event of vibrations and shocks occurring in the vehicle. The separator according to the invention can then be subjected to tensile, compressive, and torsional stresses in all directions thanks to its integral construction. The separator material may, however, preferably exhibit sufficient elasticity to compensate, for example, for variations in tolerance, aging effects, or material stresses generated by temperature differences.

[0015] The separator according to the invention may further include reinforcement elements incorporated therein, such as metal profiles and / or glass fibers, which are introduced during its manufacture to achieve a predetermined mechanical strength in the final form or to further increase this strength.

[0016] In various embodiments, a battery cell is also provided which includes at least one galvanic cell comprising an anode and a cathode, said at least one galvanic cell being incorporated or arranged in the separator according to the invention described above, such that, by means of the conductive material structure, it is possible to establish contact with said at least one galvanic cell from the outside, and that its anode and cathode are electrically connected to each other, and that a cooling circuit is established by means of the channel system. To form the cooling circuit, the channel system can be coupled to a coolant reservoir and a pump. The battery cell thus formed can exhibit all the spatial structural characteristics of the separator according to the invention described above. In a battery cell designed on the basis of the separator according to the invention, the latter can surround or contain at least two stacks of electrodes, composed of anodes and cathodes as respective galvanic cells.The separator can preferably be an integral component of the entire battery system and include all the galvanic cells. By integral component, we mean a component that does not have conventional assembly points where separate parts are joined by gluing, welding, riveting or other means, but which is manufactured as a single unit during a manufacturing process, for example by additive manufacturing, such as by a 3D printing process.

[0017] A battery cell designed based on the integrated function separator according to the invention can be a single-unit cell intended for direct use in a traction battery. The battery sub-components known to date according to the prior art, such as cell casings, cell module frames, etc., can be eliminated, as their functions are performed by the separator. The use of the integrated function separator according to the invention makes it possible to manufacture batteries that are smaller, lighter, and less expensive to produce than current batteries. The existing properties of a conventional separator—electrical and spatial separation of the electrodes of the galvanic cell—are not negatively affected by the extended functions of the separator described herein according to the invention.Similarly, other components of a conventional battery structure, such as the electronics for monitoring the different electrode stacks, can be used as before and can advantageously be directly integrated into the separator and thus mechanically fixed by it.

[0018] Busbars insulated separately from batteries known to date can also be integrated / embedded in the separator. This reduces the mounting space and materials required, thus making the corresponding battery lighter overall.

[0019] According to the invention, it also provides a method for manufacturing a separator, comprising the step of forming a separator structure by an additive process. The step of forming the separator structure includes the formation of a number of cavities for receiving at least one galvanic cell comprising an anode and a cathode, the formation of a structure made of conductive material for electrically connecting the anode and the cathode and for establishing contact with said at least one galvanic cell from the outside, and the formation of a channel system for creating a flow of cooling fluid in and through the separator. At least the housing for said at least one galvanic cell and the channel system are integrally formed within the separator. The separator provided may, in particular, be the separator described above.

[0020] The conductive material structure can be formed by depositing an electrically conductive material directly during the manufacture of the separator according to the invention or by placing / inserting prefabricated electrically conductive elements at appropriate positions in the separator structure during its manufacture.

[0021] According to other embodiments of the process, the channel system can be formed by inserting hollow molds into the separator structure. The hollow molds can be formed from a single layer or two layers and are placed at appropriate positions in the separator structure "in formation" during the additive manufacturing process.

[0022] According to other embodiments of the process, the material of the separator or the separator structure may contain a material that hardens in a delayed manner, thus allowing the separator to acquire its final strength. This aspect has already been discussed in detail in relation to the nature of the separator according to the invention.

[0023] According to other embodiments of the process, an evaporable solvent may be contained within the material of the separator structure. As already described, in the case of a non-porous separator structure, porosity may be created in the separator structure by evaporation of the solvent.

[0024] According to the invention, it further provides a method for manufacturing a battery cell, comprising implementing the method for supplying the separator according to the invention mentioned above, such that, during the formation of the separator structure by means of the additive process, the material is deposited around the anode and cathode of said at least one galvanic cell, which take the place of the cavities. In the same way as the formation of the separator structure around the electrodes of said at least one galvanic cell, other components described above can, if necessary, be placed in the separator. according to the invention, at appropriate times during the manufacturing process of the latter in order to be incorporated therein. Therefore, this manufacturing process of the battery cell refers to the case where, during the manufacture of the separator, its functional elements, such as the electrodes, bus bars and terminals, as well as the hollow bodies intended to form the channel system, are introduced into the separator structure.

[0025] It goes without saying that the characteristics mentioned above and those which will be explained further can be used not only in the combination indicated in each case, but also in other combinations or alone, without going out of the scope of the present invention.

[0026] Other advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0027] [Fig.1] represents a schematic cross-sectional view of an example embodiment of a separator with integrated function.

[0028] Figure 1 shows a schematic cross-sectional view of an example embodiment of an integrated-function separator 1. Only a portion of the separator 1 is shown; two electrodes 2, 3 – an anode 2 and a cathode 3 – of a galvanic cell are also shown. The figure illustrates the basic principle by which a corresponding battery cell can be made based on the separator 1 according to the invention. The two electrodes are incorporated into the separator 1. The separator material contains materials 4 that harden irreversibly, such that the separator 1 reaches its mechanical strength in its final three-dimensional form after a predetermined time.

[0029] In addition, channels 5 are provided in the separator 1 for liquid cooling of the electrodes 2, 3. As described previously, these can be formed by inserting hollow profiles of one or two corresponding layers into the separator structure during its manufacture. A busbar 6 incorporated into the separator 1 is also shown. The busbar 6 allows the corresponding poles of the galvanic cells of the battery cell to be connected in series or parallel, according to the desired configuration, and is capable, by its nature, of transmitting higher currents.

[0030] Of course, the invention is not limited to the embodiment described and shown in the accompanying drawings. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Demands

1. Separator (1) for spatially and electrically separating electrodes (2, 3) in a battery cell, the separator (1) comprising: a housing for at least one galvanic cell which includes an anode (2) and a cathode (3); a structure of conductive material for electrically connecting the anode (2) and the cathode (3) and for establishing contact with said at least one galvanic cell from the outside; a channel system (5) for forming a flow of cooling fluid in the separator (1); wherein at least the housing for said at least one galvanic cell and the channel system are integrally made in the separator (1).

2. Separator (1) according to claim 1, the separator containing a material which hardens in a delayed manner, thereby enabling the separator (1) to acquire its final strength.

3. Separator (1) according to claim 1 or 2, the separator (1) having a porosity which allows the transport of ions.

4. Separator (1) according to any one of claims 1 to 3, wherein the channel system (5) is constituted by hollow molds arranged in the separator (1).

5. Battery cell, comprising: at least one galvanic cell including an anode (2) and a cathode (3); wherein said at least one galvanic cell is incorporated in the separator (1) according to any one of claims 1 to 4, such that by means of the conductive material structure, it is possible to establish contact with said at least one galvanic cell from the outside and that its anode (2) and cathode (3) are electrically connected to each other and that a cooling circuit is achieved by means of the channel system (5).

6. A method for manufacturing a separator (1), comprising: the formation of a separator structure by an additive process, including: the formation of a number of cavities intended to receive at least one galvanic cell comprising an anode (2) and a cathode (3); the formation of a structure of conductive material intended to electrically connect the anode and the cathode and to establish contact with said at least one galvanic cell from the outside; the formation of a channel system (5) intended to form a flow of cooling fluid in the separator (1); wherein at least the housing intended for said at least one galvanic cell and the channel system (5) are integrally made in the separator.

7. Method according to claim 6, wherein the channel system (5) is formed by inserting hollow molds into the separator structure.

8. A method according to claim 6 or 7, wherein the material of the separator structure contains a material which hardens in a delayed manner, thereby enabling the separator (1) to acquire its final strength.

9. A method according to any one of claims 6 to 8, wherein an evaporable solvent is contained in the material of the separator structure.

10. A method for manufacturing a battery cell, comprising: implementing the method for supplying a separator (1) according to any one of claims 6 to 9, in such a way that, during the formation of the separator structure by means of the additive process, the material is deposited around the anode and cathode of said at least one galvanic cell, which take the place of the cavities.

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