CN107275524B

CN107275524B - Battery cell

Info

Publication number: CN107275524B
Application number: CN201710197391.4A
Authority: CN
Inventors: D.绍尔泰格; H.赖因斯哈根; S.波勒
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2016-03-30
Filing date: 2017-03-29
Publication date: 2021-10-08
Anticipated expiration: 2037-03-29
Also published as: CN107275524A; DE102016205160A1

Abstract

The invention relates to a battery cell (2) comprising a battery case (3) in which an electrode unit (10) is arranged, wherein the electrode unit (10) has an anode (21) connected to the negative terminal (11) and a cathode (22) connected to the positive terminal (12), characterized in that the electrode unit (10) is configured as an electrode stack having a plurality of layers of an anode (21) and a plurality of layers of a cathode (22), the layers are stacked one on top of the other in a stacking direction (x), and the battery case (3) is constructed in a prismatic shape, wherein all faces of the battery case (3) extend parallel to the stacking direction (x) or at right angles thereto, and the battery case (3) has a first case member (61) forming the negative terminal (11) and a second case member (62) forming the positive terminal (12).

Description

Battery cell

Technical Field

The present invention relates to a battery cell comprising a battery case in which an electrode unit is disposed, wherein the electrode unit has an anode connected to a negative terminal and a cathode connected to a positive terminal.

Background

The electrical energy can be stored by means of a battery. The battery converts chemical reaction energy into electric energy. Here, the primary battery pack and the secondary battery pack are different. The primary battery pack functions only once, while the secondary battery pack, also called a battery, can be recharged. So-called lithium ion battery cells are used in particular in secondary batteries. In addition, such lithium ion battery cells are characterized by high energy density, thermal stability, and minimal self-discharge.

Lithium ion battery cells have a positive electrode, also referred to as the cathode, and a negative electrode, also referred to as the anode. The cathode and anode include a respective electrical conductor to which the active material is applied. The electrodes of the battery cell are constructed in the shape of a thin film and rolled up into one electrode winding or stacked into an electrode stack having a plurality of electrode layers with a separator (separator separating the anode from the cathode) interposed therebetween. The two electrodes of the electrode unit are electrically connected with the poles of the battery cells, which are also referred to as terminals. The electrodes and the separator are surrounded by a normally liquid electrolyte.

A battery cell of the generic type is known, for example, from DE 102012223796 a1, which comprises an electrode unit with an anode and a cathode. The battery cell has a cell casing which is made of metal, for example, and is formed in a prismatic, in particular square, shape. The anode and cathode are connected to terminals by current collectors, which are disposed outside the battery case.

From US 2012/0276437, a battery cell is known which has an electrode stack which is arranged in a metallic housing. The housing comprises two housing parts which are electrically insulated from one another by a sealing. The anode and cathode of the cell stack have contact flags therein, which are electrically connected to one housing part each. The case member thus forms the terminals of the battery cells.

From JP 2011-. The housing here likewise comprises two housing parts which form the terminals of the battery cells.

Disclosure of Invention

A battery cell, in particular a lithium ion battery cell, is suggested, comprising a battery housing in which an electrode unit is arranged. The electrode unit has an anode electrically connected to the negative terminal of the battery cell and a cathode electrically connected to the positive terminal of the battery cell.

According to the invention, the electrode unit is designed as an electrode stack having a plurality of layers of anodes and a plurality of layers of cathodes. The layers of the anode and the layers of the cathode are stacked one on top of the other in the stacking direction. The battery case is constructed in a prismatic shape in which all faces of the battery case extend parallel or perpendicular to the stacking direction. The battery case has a first case member forming a negative terminal and a second case member forming a positive terminal.

In this context, one such body is called a prism, i.e. its sides are as long as they are, and its base surface is polygonal. The battery case of the battery cell here has the shape of a straight prism, wherein the base of the prism is at right angles to the stacking direction of the electrode units.

According to an advantageous embodiment of the invention, the first housing part forming the negative terminal and the second housing part forming the positive terminal are electrically conductive, in particular metallic. The first housing part and the second housing part can be electrically insulated from one another by a surrounding insulator.

The insulator advantageously projects into the mounting element, which has a cooling channel and/or a voltage connection and/or a sensor. The attaching member is thus securely coupled with the battery case of the battery cell.

According to an advantageous variant of the invention, the anode has a contact flag and the cathode has a contact flag. Here, the contact flag of the anode and the contact flag of the cathode protrude on opposite sides from the electrode unit configured as an electrode stack.

The contact flag of the anode is preferably connected directly to the first housing part. The contact flag of the cathode is also preferably directly connected to the second housing member. It is therefore preferred that no additional current collector is required and used to connect the contact flag with the housing member.

According to an advantageous embodiment of the invention, the contact flag material of the anode is connected in a bonded manner to the first housing part. Likewise, the contact flag of the cathode is advantageously connected in a material-bonded manner to the second housing part.

According to a further advantageous embodiment of the invention, the contact flag of the anode is connected to the first housing part in a form-fitting manner. Likewise, the contact flag of the cathode is advantageously connected with a form-fit with the second housing part.

According to an advantageous variant of the invention, the base surface of the prismatic battery case, which is at right angles to the stacking direction, has a hexagonal shape.

According to another advantageous variant of the invention, the first housing part has a protruding bulge. The second case member also has a protruding boss. The electrical contact of the case member forming the terminal of the battery cell is facilitated by the protruding bosses.

The battery cells according to the invention are advantageously used in Electric Vehicles (EV), Hybrid Electric Vehicles (HEV), plug-in hybrid electric vehicles (PHEV), in particular stationary battery cells for stabilizing the domestic power grid, battery cells in maritime applications (for example shipbuilding or motorboats) or battery cells in aeronautical applications (in particular in aircraft construction). Other applications are also contemplated.

Advantages of the invention

The construction of the battery cell according to the invention advantageously increases the electrochemically usable volume in the battery housing. This is particularly true when the contact flag of the electrode is directly connected to the housing member, thus eliminating the need for an additional current collector to connect the electrode to the terminal. The volume saved can be used, for example, for an external sensor system or for a cooling system. Furthermore, the connection of a plurality of battery cells to one another is also achieved while the available volume is effectively utilized.

By arranging the contact flags of the electrodes on opposite sides, the current density within the electrode unit is homogenized, which results in an extended service life of the battery cell.

Drawings

Embodiments of the invention are explained in more detail with the aid of the figures and the description below.

The figure is as follows:

fig. 1 is a schematic sectional view of a battery cell;

fig. 2 is a partially transparent schematic view of a battery cell according to a first embodiment;

FIG. 3 is a schematic diagram of a cross section of an electrode for the battery cell of FIG. 2;

fig. 4 is a partially transparent schematic view of a battery cell according to a second embodiment;

FIG. 5 is a schematic diagram of a cross section of an electrode for the battery cell of FIG. 4;

fig. 6 is a partially transparent schematic view of a battery cell according to a third embodiment;

fig. 7 is a partially transparent schematic view of a battery cell according to a fourth embodiment;

fig. 8a and 8b are schematic sectional views of a battery cell having one possible connection of the contact flag and the case member;

fig. 9 is a schematic sectional view of a battery cell having another possible connection of the contact flag and the case member;

fig. 10 is a schematic sectional view of a battery cell having still another possible connection of contact flags with a case member;

fig. 11 is a schematic sectional view of a battery cell having still another possible connection of contact flags to a case member;

fig. 12 is a schematic sectional view of a battery cell having still another possible connection of contact flags with a case member;

FIG. 13 is a partially transparent schematic detail view of the battery cell of FIG. 2 with an attachment member; and

fig. 14 is a schematic sectional view of the battery cell of fig. 13.

Detailed Description

In the following description of embodiments of the invention, identical or similar elements are denoted by identical reference numerals, wherein repeated descriptions of these elements are omitted in individual cases. The figures only schematically show the subject of the invention.

Fig. 1 is a schematic sectional view of a battery cell 2. The battery cell 2 includes a battery case 3, which is constructed to be electrically conductive. The battery case 3 has a first case member 61 and a second case member 62, which are electrically insulated from each other by the surrounding insulator 50. The shell member is made of metal, such as aluminum. The first case member 61 forms the negative terminal 11 and the second case member 62 forms the positive terminal 12. The voltage supplied by the battery cells 2 can be taken via the terminals 11, 12. The battery cell 2 can also be charged via the terminals 11, 12.

Inside the battery case 3 of the battery cell 2, there is disposed an electrode unit 10 constructed in an electrode stack having two electrodes, i.e., an anode 21 and a cathode 22. The anode 21 and the cathode 22 are each configured in the form of a thin film and each have a plurality of layers. The layers of the anode 21 and the layers of the cathode 22 are stacked one on top of the other in the stacking direction x with the separator 18 in the form of a thin film layer in between.

The battery case 3 is configured in a prismatic shape. The battery housing 3 has a base surface and a cover surface which are congruent and which are oriented parallel to one another and at right angles to the stacking direction x. Furthermore, the battery case 3 has a plurality of side faces that are oriented parallel to the stacking direction x.

The anode 21 includes an anode active material 41, which is configured in a thin film shape. The anode 21 also comprises an electrical conductor 31, which is likewise configured in the form of a film and is electrically conductive. The active material 41 of the anode is now arranged on both sides of the current conductor 31 of the anode 21 and is connected to this current conductor. The cathode 22 includes a cathode active material 42, which is configured in a thin film shape. The cathode 22 also comprises an electrical conductor 32, which is likewise configured in the form of a film and is electrically conductive. The active material 42 of the cathode is now arranged on both sides of the electrical conductor 32 of the cathode 22 and is connected to this electrical conductor.

The electrical conductors 31 of the layers of the anode 21 each have, in the end region, contact flags 35 of the anode 21, which project from the electrode unit 10. The electrical conductors 32 of the layers of the cathode 22 each have, in the end region, contact flags 36 of the cathode 22, which project from the electrode unit 10. The contact flags 35 of the anode 21 and the contact flags 36 of the cathode 22 here project from the electrode unit 10 on opposite sides along the longitudinal direction y. The longitudinal direction y is here perpendicular to the stacking direction x. The transverse direction z, which is also used in the following, is at right angles to the stacking direction x and at right angles to the longitudinal direction y.

The contact flag 35 of the anode 21 is guided to the first housing part 61 and connected to this first housing part at the negative coupling position 71. The negative terminal 11 of the battery cell 2 is electrically connected to the anode 21. The contact flag 36 of the cathode 22 is guided to the second housing member 62 and connected to this second housing member at the positive coupling position 72. Thus, the positive terminal 12 of the battery cell 2 is electrically connected to the cathode 22.

Fig. 2 shows a partially transparent schematic illustration of a battery cell 2 according to a first exemplary embodiment. The base surface of the battery can 3 here has a hexagonal shape. The battery case 3 has two side faces oriented at right angles to the longitudinal direction y. The battery housing 3 furthermore has two side faces which are oriented at right angles to the transverse direction z. The battery housing 3 also has two side faces which are inclined at an angle of currently 45 ° to the longitudinal direction y and the transverse direction z. At one of the two sides there is a negative coupling position 71 where the contact flag 35 of the anode 21 is connected with the first case member 61. At the other of the two sides there is a positive coupling location 72 where the contact flag 36 of the cathode 22 is connected with the second case member 62.

Fig. 3 shows a schematic representation of a section of the electrode for the battery cell 2 of fig. 2, in the present case the cathode 22. The cathode active material 42 is applied to the film-shaped current conductor 32 of the cathode 22, wherein the current conductor 32 of the cathode 22 is free of the cathode active material 42 in each lateral strip. The individual layers of the cathode 22 are currently blanked to a 45 ° angle. One corner of the punched layer projects into the free strip of the electrical conductor 32 of the cathode 22 and there forms a contact flag 36 of the cathode 22. Gaps are provided at the opposing corners. The layers of the anode 21 are punched out similarly. The layers of the anode 21 and the intermediate layers of the cathode 22 and the layers of the separator 18 are then stacked such that the contact flag 36 of the cathode 22 is above the gap of the anode 21 and the contact flag 35 of the anode 21 is above the gap of the cathode 22. The contact flags 35, 36 can be extended if necessary by welding additional blocks.

Fig. 4 shows a partially transparent schematic representation of a battery cell 2 according to a second embodiment. Two projecting ridges are provided on each of the two opposite sides of the battery case 3 in the longitudinal direction y. A negative coupling location 71 is in the region of one of the protruding bumps, where the contact flag 35 of the anode 21 is connected with the first housing part 61. The positive coupling position 72, at which the contact flag 36 of the cathode 22 is connected with the second housing member 62, is in the region of the other raised boss. The two projecting elevations are arranged diagonally opposite one another, i.e. opposite one another in the longitudinal direction y and in the transverse direction z, on the battery housing 3.

Fig. 5 is a schematic diagram of one cross section, now the cathode 22, of the electrode for the battery cell 2 of fig. 4. The cathode active material 42 is applied to the film-shaped current conductor 32 of the cathode 22, wherein one strip of the current conductor 32 of the cathode 22 in the lateral direction is free of the cathode active material 42. The individual layers of the cathode 22 are blanked: so that a part of the punched out layer projects into the free strip of the electrical conductor 32 of the cathode 22 and there forms the contact flag 36 of the cathode 22. The layers of the anode 21 are punched out similarly. The layers of the anode 21 and the intermediate layers of the cathode 22 and the layers of the separator 18 are then stacked such that the contact flag 36 of the cathode 22 is diagonally offset from the contact flag 35 of the anode 21. The contact flags 35, 36 may be extended if necessary by welding additional parts.

Fig. 6 is a partially transparent schematic view of a battery cell 2 according to a third embodiment, which is largely similar to the second embodiment. In contrast to the battery cell 2 according to the second exemplary embodiment, in the battery cell 2 according to the third exemplary embodiment, the protruding beads at the battery housing 3 are arranged opposite in the longitudinal direction y and flush in the transverse direction z.

Fig. 7 is a partially transparent schematic view of a battery cell 2 according to a fourth embodiment, which is largely similar to the second embodiment. In contrast to the battery cell 2 according to the second exemplary embodiment, in the battery cell 2 according to the fourth exemplary embodiment, the convex bulges on the battery housing 3 are arranged in an opposing and central manner in the longitudinal direction y and flush with one another in the transverse direction z.

Fig. 8a and 8b are schematic sectional views of the battery cell 2 with possible connection of the contact flag 35 of the anode 21 to the first case member 61. The second case member 62 and the insulator 50 are not shown here. The contact flag 35 of the anode 21 is here guided from the electrode unit 10 to the base surface of the battery case 3 in the stacking direction x and in the longitudinal direction y. From there, the contact flag 35 of the anode 21 extends parallel to the base surface along the longitudinal direction y to the side of the battery case 3. The contact flag 35 of the anode 21 continues to extend away from the base surface in the stacking direction x.

Fig. 8a shows a first step for connecting the contact flag 35 of the anode 21 and the first case member 61. In said side face a projecting lug is provided, to which the contact flag 35 of the anode 21 is guided. The contact flag 35 of the anode 21 is connected in the present material-bonded manner, for example by means of ultrasonic welding, resistance welding or laser welding, to the projecting lug which represents the negative connection point 71. As an alternative, the contact flag 35 of the anode 21 can also be connected in a form-fitting manner, for example by snapping or clipping, to the protruding lug which represents the negative coupling point 71.

In the next step shown in fig. 8b, the negative coupling position 71 is bent into the battery can 3 together with the contact flag 35 of the anode 21 connected thereto.

Fig. 9 shows a schematic cross-sectional view of the battery cell 2 with another possible connection of the contact flag 35 of the anode 21 to the first case member 61. The contact flag 35 of the anode 21 is here guided from the electrode unit 10 to the base surface of the battery case 3 in the stacking direction x and in the longitudinal direction y. The contact flag 35 of the anode 21 is directly connected, preferably materially bonded, to the first housing part 61 at a negative coupling location 71 on the base surface. The insulator 50, which insulates the first housing part 61 from the second housing part 62, is here partially located inside the battery housing 3 and partially outside the battery housing 3 and is connected to the housing parts 61, 62 by means of the housing connector 56. The case connector 56 is, for example, an adhesive.

Fig. 10 shows a schematic cross-sectional view of the battery cell 2 with another possible connection of the contact flag 35 of the anode 21 to the first case member 61. The contact flag 35 of the anode 21 is here guided from the electrode unit 10 to the base surface of the battery case 3 in the stacking direction x and in the longitudinal direction y. From there, the contact flag 35 of the anode 21 extends parallel to the base surface along the longitudinal direction y to the side of the battery case 3. The flag 35 of the anode 21 is directly connected, preferably materially bonded, to the first housing part 61 at a negative coupling location 71 on this side. The insulator 50, which insulates the first case member 61 from the second case member 62, is configured similarly to that shown in fig. 9 and is connected to the case members 61, 62.

Fig. 11 is a schematic sectional view of the battery cell 2 having still another possible connection of the contact flag 35 of the anode 21 to the first case member 61. The contact flags 35 of the anode 21 are here guided from the electrode unit 10 first in the stacking direction x and in the longitudinal direction y to the coupling elements 54 connected with the first housing part 61. The contact flag 35 of the anode 21 is preferably connected in a form-fitting manner to the coupling element 54 at a negative coupling location 71 at the coupling element 54. The contact flag 35 of the anode 21 is indirectly connected to the first case member 61. The insulator 50, which insulates the first case member 61 from the second case member 62, is configured similarly to that shown in fig. 9 and is connected to the case members 61, 62.

Fig. 12 is a schematic sectional view of the battery cell 2 having still another possible connection of the contact flag 35 of the anode 21 to the first case member 61. The contact flag 35 of the anode 21 is here led from the electrode unit 10 first in the longitudinal direction y to the current collector 52 and is connected to this current collector. The current collector 52 is connected to the first case member 61 at a negative coupling position 71 at the first case member 61. The contact flag 35 of the anode 21 is indirectly connected to the first case member 61. The insulator 50, which insulates the first case member 61 from the second case member 62, is configured similarly to that shown in fig. 9 and is connected to the case members 61, 62.

Fig. 13 shows a partially transparent detail view of the battery cell 2 of fig. 2 with an attachment element 80. The attachment element 80 is of prismatic configuration and has a triangular base surface in the present case. The attachment member 80 abuts to the side of the battery case 3 at which the positive coupling position 72 is located, and which is oriented obliquely with respect to the longitudinal direction y and the lateral direction z at an angle of currently 45 °. The other attachment element 80 abuts to the side of the battery pack case 3 at which the negative coupling position 71 is located and which is oriented obliquely with respect to the longitudinal direction y and the transverse direction z at the present angle of 45 °. The attachment member 80 is constructed such that the battery case 3 and the attachment member 80 complement a rectangular body.

The mounting element 80 now has two cooling channels 84 extending in the stacking direction x and a negative voltage connection 81 and a positive voltage connection 82, which cannot be seen in this figure. The attachment element 80 may also have other elements, such as sensors.

Fig. 14 shows a sectional view of the battery cell 2 of fig. 13 along a sectional line S, which extends obliquely to the longitudinal direction y as well as to the transverse direction z. The contact flag 36 of the cathode 22 is guided from the electrode unit 10 to the base surface of the battery case 3. The contact flag 36 of the cathode 22 is directly connected to the second housing member 62 at the positive attachment location 72 on the base surface. The insulator 50, which insulates the first case member 61 from the second case member 62, is configured similarly to that shown in fig. 9 and is connected to the case members 61, 62.

The insulator 50 here projects into the attachment element 80. The attachment member 80 is thus firmly connected to the battery case 3. Preferably, the insulator 50 is also made of a material that conducts heat well, thereby improving the conduction of heat from the inside of the battery case 3 to the cooling channel 84 in the attaching member 80. The insulating body 50 can have, for example, a metallic core with an electrically insulating coating. The negative voltage terminal 81 is connected to the first case member 61 forming the negative terminal 11. The positive voltage terminal 82 is connected to the second case member 62 forming the positive terminal 12.

The present invention is not limited to the embodiments described herein and the aspects emphasized herein. In fact, within the scope given by the present invention, many variations are possible within the scope of practice of the person skilled in the art.

Claims

1. A battery cell (2) comprising a battery case (3) in which an electrode unit (10) is disposed, wherein the electrode unit (10) has an anode (21) connected to a negative terminal (11) and a cathode (22) connected to a positive terminal (12),

it is characterized in that the preparation method is characterized in that,

the electrode unit (10) is configured as an electrode stack having a plurality of layers of anodes (21) and a plurality of layers of cathodes (22) stacked one above the other in a stacking direction (x),

and the battery case (3) is configured in a prismatic shape, wherein all faces of the battery case (3) are parallel or perpendicular to the stacking direction (x), and

the battery case (3) has a first housing part (61) forming the negative terminal (11) and a second housing part (62) forming the positive terminal (12), the first housing part (61) and the second housing part (62) being designed to be metallic and electrically insulated from one another by a surrounding insulating body (50), the insulating body (50) projecting into an attachment element (80) having a cooling channel (84) and/or voltage terminals (81, 82) and/or a sensor.

2. The battery cell (2) according to claim 1,

the anode (21) has a contact flag (35) and the cathode (22) has a contact flag (36), wherein the contact flag (35) of the anode (21) and the contact flag (36) of the cathode (22) protrude from the electrode unit (10) at opposite sides.

3. The battery cell (2) according to claim 2, wherein the contact flag (35) of the anode (21) is directly connected with the first case member (61), and/or,

the contact flag (36) of the cathode (22) is directly connected to the second case member (62).

4. Battery cell (2) according to claim 3, characterized in that the contact flag (35) of the anode (21) is connected with the first housing part (61) in a material-bonded manner and/or,

the contact flag (36) of the cathode (22) is materially bonded to the second housing member (62).

5. Battery cell (2) according to claim 3, characterized in that the contact flag (35) of the anode (21) is connected with a form fit with the first housing part (61) and/or,

the contact flag (36) of the cathode (22) is connected with the second housing part (62) in a form-fitting manner.

6. Battery cell (2) according to any of the claims 1 to 5,

the base surface of the battery case (3) at right angles to the stacking direction (x) has a hexagonal shape.

7. Battery cell (2) according to any of the claims 1 to 5,

the first case member (61) has a protruding boss, and/or,

the second case member (62) has a protruding boss.

8. Use of a battery cell (2) according to any of the preceding claims in an Electric Vehicle (EV), a Hybrid Electric Vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a stationary battery pack, a battery pack in maritime applications or a battery pack in aeronautical applications.