Cell casing and battery cell

Abstract

The invention relates to a cell housing (11) for receiving an electrochemically active electrode element arrangement (15) for a battery cell (1) designed as a prismatic hard-shell cell, comprising a container element (111) open at one end, and a lid element (112) designed to receive at least one cell terminal (14) and which can be connected to the container element (111) in a liquid-tight manner, wherein the container element (111) and the lid element (112) are made of electrically non-conductive material. The invention further relates to an electrochemical battery cell (1) with such a cell housing (11).

Description

[0001] The invention relates to a cell housing for accommodating an electrochemically active electrode element arrangement for a battery cell designed as a hard-shell cell. The invention further relates to an electrochemical battery cell with such a cell housing.

[0002] Electrochemical battery cells for arrangement in high-voltage batteries for vehicle applications are known from the prior art, for example, DE 21 2013 000 214 U1 and EP 3 794 665 B1. These cells are designed as cylindrical, cuboid-shaped, or otherwise prismatic hard-shell cells. The term "prismatic" is intended to encompass all designs in which the cell housing has base and top surfaces that are identical in shape and size. Battery cells designed as prismatic hard-shell cells comprise an electrochemically active electrode element arrangement, for example in the form of an electrode foil coil or an electrode foil stack, which is arranged together with a liquid electrolyte in a rigid cell housing.

[0003] Cell casings for prismatic battery cells are typically made of a metallic material, such as aluminum, to achieve high mechanical strength. They usually comprise a container element that is open on one side and a cover element designed to accommodate cell terminals. This cover element is integrally bonded to the container element to create a liquid-tight seal around the cell casing. Inside the cell casing, the electrode element arrangement must be insulated from the cell casing in order to maintain the electrical clearance and creepage distances. For this purpose, the electrode element arrangement must be insulated from the cell casing in a separate process before being inserted into the cell casing. This is typically achieved by wrapping the electrode element arrangement with one or more external insulating elements, such as a Mylar film.These inner insulating elements are generally not liquid-tight, so the cell casing is in contact with the electrolyte, creating a positive electrical potential across the cell casing. For this reason, and to maintain electrical clearance and creepage distances outside the battery cell, the exterior of the cell casing must also be insulated in a separate process to prevent potential flashovers and insulation failures. This is typically achieved by wrapping the cell casing with one or more outer insulating elements, such as a Mylar film, and then gluing the outer insulating element(s) to the cell casing.

[0004] The invention is based on the object of providing a cell housing which is improved compared to the prior art, in particular constructed from fewer parts and which can be produced more easily and cost-effectively, as well as a correspondingly improved electrochemical battery cell.

[0005] With regard to the cell housing, the object is achieved according to the invention by the features specified in claim 1. With regard to the electrochemical battery cell, the object is achieved according to the invention by the features specified in claim 6.

[0006] Advantageous embodiments of the invention are the subject of the subclaims.

[0007] In a cell housing for accommodating an electrochemically active electrode element arrangement for a battery cell designed as a prismatic hard-shell cell, comprising a container element open on one side, and a cover element designed to accommodate at least one cell terminal and connectable to the container element in a liquid-tight manner, it is provided according to the invention that the container element and the cover element are formed from, for example consist of, electrically non-conductive material.

[0008] By using non-metallic, electrically non-conductive housing materials, the number of components required for a battery cell can be significantly reduced, simplifying manufacturing processes and reducing the number of steps required. Furthermore, this eliminates any electrical potential from the electrolyte to the cell housing, thus preventing electrochemical corrosion with the housing over its lifetime.

[0009] According to one embodiment, the electrically non-conductive material can be a plastic. Plastics are inexpensive, easy to process, chemical-resistant, and electrically non-conductive.

[0010] For example, the plastic can be an injection-moldable thermoplastic. Injection molding is an established, reliably controllable primary molding process that enables the production of large quantities in a short time and with high manufacturing quality. Advantageously, it can also be provided that the at least one cell terminal is embedded in the cover element as an overmolded insert. This eliminates at least one additional process step because the cell terminal is electrically insulated and connected to the cover element in a liquid-tight manner immediately after production.

[0011] In other embodiments, the electrically non-conductive material may be a thermosetting plastic, a technical ceramic, or a fiber composite material. The advantage of these materials lies in their greater strength than most thermoplastic materials, as well as in their higher temperature resistance.

[0012] The aforementioned advantages of the cell housing according to the invention are naturally transferred to a battery cell manufactured using such a cell housing. In a battery cell designed as a prismatic hard-shell cell, comprising a cell housing with at least two cell terminals, an electrochemically active electrode element arrangement arranged in the cell housing, and an electrolyte arranged in the cell housing, the invention therefore provides that the cell housing is also designed according to the invention as described above.

[0013] During manufacture of the battery cell, its internal components, namely an electrochemically active electrode element arrangement, are arranged in the container element which is open on one side, before the container element is closed by the cover element. According to one embodiment of the invention, such a battery cell can be manufactured particularly advantageously, namely simply and cost-effectively, in that the electrically non-conductive material of the container element and the cover element of the cell housing is weldable and the container element and the cover element are joined to one another by welding, for example by laser welding. This also results in the plant-related advantage that the non-metallic cell housings can be laser-welded in conventional production systems, i.e. systems already used in battery cell production.As already explained in connection with the proposed cell housing, thermoplastics, for example, can be used as a weldable material for the cell housing.

[0014] Alternatively, it can also be provided that the electrically non-conductive material is not weldable, and the container element and the lid element are / are bonded together by adhesive bonding. This design is suitable, for example, for the use of thermosetting plastic, technical ceramics, or fiber composite materials, as already explained in connection with the proposed cell housing.

[0015] The inventive design of the cell housing of the proposed battery cell advantageously allows the electrode element arrangement to be arranged uninsulated in the cell housing.

[0016] In summary, the invention can achieve the following advantageous effects: • simple and cost-effective way to reduce the number of components in the battery cell and the costs of production, • no additional insulation of the cell housing necessary, • Electrocorrosion of the housing can be avoided, and • Use of injection molding processes (e.g. for plastic) to produce the cell housing • Reduced weight due to the use of plastic.

[0017] Embodiments of the invention are explained in more detail below with reference to drawings.

[0018] Showing: Fig. 1 an exploded view of a prismatic battery cell according to the prior art, Fig. 2 an exploded view of a cell housing according to the prior art, Fig. 3 an exploded view of a cell housing according to the invention, Fig. 4 closing the cell housing by laser welding, and Fig. 5 examples of different designs of prismatic battery cells.

[0019] Corresponding parts are provided with the same reference numerals in all figures.

[0020] Fig. 1 shows a battery cell 1 and Fig. 2 a cell housing 11, both according to the prior art, in an exploded view.

[0021] The cell housing 11 comprises a container element 111 with a rectangular base and vertical side walls, and is open on one side, opposite the base, at its top. An electrode element assembly 15 is inserted into this container element 111. The electrode element assembly 15 is surrounded by internal insulating elements 22, but is not liquid-tight.

[0022] The electrode element assembly 15 is arranged together with the inner insulating element 22 in the container element 111 of the cell housing 11. The electrode element assembly 15 is also electrically connected to the cell terminals 14, which are electrically insulated from the cover element 112 by terminal insulators 141. Subsequently, the container element 111 and the cover element 112 are connected to one another in a liquid-tight manner. The cover element 112 also has a DMC (Data Matrix Codes) label 13 and a seal 12, which closes a vent opening provided in the cover element 112 and thus acts as a pressure relief valve.

[0023] The container element 111 and the lid element 112 are made of aluminum, meaning they are electrically conductive. The cell housing 11 is electrically insulated from the outside by two outer insulating elements 21, which are glued to the outer sides of the container element 111 and the lid element 112.

[0024] Fig. 3 schematically shows a cell housing 11 according to the invention for accommodating an electrochemically active electrode element arrangement 15 for a battery cell 1 designed as a prismatic hard-shell cell (not shown here).

[0025] As in the prior art, the cell housing 11 according to the invention comprises a container element 111 with a rectangular base surface and vertical side walls and is open on one side, opposite the base surface, at its top. An electrode element arrangement 15 (not shown here) is introduced into this container element 111, and the container element 111 is then closed in a liquid-tight manner by the cover element 112. The container element 111 and the cover element 112 are made of thermoplastic material, i.e., they are electrically non-conductive, and are manufactured using an injection molding process. Two cell terminals 14 are embedded in the cover element 112 as overmolded inserts, i.e., without separate terminal insulators 141. Unlike in the prior art, the electrode element arrangement 15 does not need to be electrically insulated from the cell housing 11 because it is electrically non-conductive.For the same reason, the cell housing 11 does not need to be electrically insulated from the outside.

[0026] In the cell housing 11 according to the invention of the illustrated embodiment, the cover element 112 also has a DMC label 13 and a seal 12, which closes a vent opening provided in the cover element 112 and thereby acts as a pressure relief valve.

[0027] The thermoplastic material from which the container element 111 and the cover element 112 are made is weldable, so that the liquid-tight connection between them can be produced, for example, by laser welding, as has previously been the case for conventional cell housings 11 made of metallic materials such as aluminum, so that the battery cell 1 according to the invention can be manufactured on the same production facilities. Fig. 4 shows that there is no difference between the laser welding of the cell housing 11 by means of a laser welding device 3 according to the prior art (left illustration) and the laser welding of the cell housing 11 according to the invention by means of a laser welding device 3 (right illustration).

[0028] In the same way, Fig. 5 that the cell housings 11 according to the invention (right illustration) can take on the same shapes as the conventional cell housings 11 (left illustration), ie prismatic battery cells 1 can, as before, also have, for example, a rectangular, hexagonal, round base and cover surface, so that the conventional battery cells can be easily replaced at any time by the battery cells 1 according to the invention without having to change anything on the battery module.

[0029] The features and advantages described herein with respect to a cell casing may also relate to a battery cell described herein and vice versa. List of reference symbols 1 battery cell 11 Cell housing 111 Container element 112 cover element 12 Sealing 13 DMC labels 14 Cell terminal 141 Terminal insulator 15 Electrode element arrangement 21 outer insulating element 22 inner insulating element 3 Laser welding device QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 21 2013 000 214 U1

[0002] EP 3 794 665 B1

[0002]

Claims

[1] Cell housing (11) for accommodating an electrochemically active electrode element arrangement (15) for a battery cell (1) designed as a prismatic hard-shell cell, comprising a container element (111) open on one side, and a cover element (112) designed to receive at least one cell terminal (14) and connectable to the container element (111) in a liquid-tight manner, characterized by , that the container element (111) and the lid element (112) are formed from electrically non-conductive material. [2] Cell housing (11) according to claim 1, characterized by that the electrically non-conductive material is a thermoplastic. [3] Cell housing (11) according to claim 2, characterized by that the thermoplastic material is injection-moldable and the container element (111) and the lid element (112) are produced by injection molding. [4] Cell housing (11) according to claim 3, characterized bythat the at least one cell terminal (14) is embedded in the cover element (112) by overmolding with plastic. [5] Cell housing (11) according to claim 1, characterized by that the electrically non-conductive material is a thermosetting plastic or a technical ceramic or a fiber composite material. [6] Battery cell (1) which is designed as a prismatic hard-shell cell, comprising a cell housing (11) with at least two cell terminals (14), an electrochemically active electrode element arrangement (15) arranged in the cell housing (11), and an electrolyte arranged in the cell housing (11), characterized by , that the cell housing (11) is designed according to one of claims 1 to 5. [7] Battery cell (1) according to claim 6 characterized bythat the electrically non-conductive material is weldable and the container element (111) and the lid element (112) are connected to one another by laser welding. [8] Battery cell (1) according to claim 6 characterized by that the electrically non-conductive material is not weldable and the container element (111) and the lid element (112) are connected to one another by gluing. [9] Battery cell (1) according to one of claims 6 to 8, characterized by that the electrode element arrangement (15) is arranged uninsulated in the cell housing (11).

Images