Electrochemical single cell and battery

Abstract

The invention relates to an electrochemical single cell (10) for a battery, in particular for a high-voltage traction battery of an electrically powered vehicle, comprising at least a cell housing (12) with a first terminal (22) and a second terminal (24), an electrode assembly (30) arranged in an interior (14) of the cell housing (12), which has a plurality of first and second electrodes (32, 34), each separated by a separator. The first and second electrodes (32, 34) have conductors (36, 38) which project from the first and second electrodes (32, 34) in an axial direction (80), wherein the conductors (36, 38) are electrically connected to the first terminal (22) and the second terminal (24) by means of electrical connecting lines (26). The conductors (36, 38) of at least one of the two electrodes (32, 34) are subdivided by slots (46) extending in the axial direction (80). The invention further relates to a battery (100) with electrochemical individual cells (10) connected in series and / or parallel with each other.

Description

[0001] The invention relates to an electrochemical single cell for a battery, in particular for a high-voltage traction battery of an electrically driven vehicle, and to a battery, in particular a high-voltage traction battery of an electrically driven vehicle.

[0002] Traction batteries for electric vehicles contain multiple battery cells, often designed as so-called prismatic hardcase cells. These contain wound or stacked electrodes.

[0003] A battery cell with an electrode coil is known from WO 2022 / 061187 A1. An electrode of the electrode coil has many directly adjacent conductor tabs. These small conductor tabs can be mechanically folded at an angle of 90° within an electrode coil, i.e., at curves. Electrically, the conductor tabs behave like a continuous, wide conductor with regard to the transition of the electron flow from the individual conductor tabs to the main electrode surface, i.e., as if the slots between the conductor tabs were not present.

[0004] An object of the invention is to provide an improved electrochemical single cell for a battery, in particular for a high-voltage traction battery of an electrically powered vehicle.

[0005] A further object is to create an improved battery, in particular a high-voltage traction battery for an electrically powered vehicle.

[0006] The above-mentioned objects are solved by the features of the independent claims.

[0007] Advantageous embodiments and advantages of the invention emerge from the further claims, the description and the drawings.

[0008] According to one aspect of the invention, an electrochemical single cell for a battery, in particular for a high-voltage traction battery of an electrically powered vehicle, is proposed, at least comprising a cell housing with a first terminal connection and a second terminal connection, and an electrode pack arranged in an interior of the cell housing, which electrode pack has a plurality of first and second electrodes, each separated by a separator. The first and second electrodes have conductors that protrude from the first and second electrodes in an axial direction, wherein the conductors are electrically connected to the first terminal connection and the second terminal connection by means of electrical connecting lines. The conductors of at least one of the two electrodes are divided by slots running in the axial direction.

[0009] In the proposed single electrochemical cell, the conductors of at least the first electrode or the second electrode are slotted and therefore consist of individual conductor tabs. All conductors of the first and second electrodes can also be slotted. A geometric extension, for example, a circular one, can be attached to the electrode-side end of the slots in the conductors.

[0010] Advantageously, the electrical potential is scaled according to the number of arrester tabs, thus reducing the profile. Only very close to the arrester tabs is the potential curve curved. Even in the immediate vicinity of the arrester tabs, the individual potentials of the respective arrester tabs superimpose themselves to form a common sum potential, which is thus flattened compared to the potential curve of an unslotted arrester. The potential curve remains relatively flat over large sections of the electrode foil. Therefore, the voltage difference to the neighboring electrode, especially near the arrester, is constant across the electrode width.

[0011] The ion flow between an electrode and a neighboring electrode located in front of or behind it is essentially homogeneous. This is because the ion flow is driven perpendicular to the electrode surface by the local potential difference between two neighboring electrodes.

[0012] The active material of the electrodes therefore has a substantially uniform current density. This results in flatter charge and discharge curves. The electrochemical cell has a higher energy density because the active material is distributed more uniformly and thus better utilized. The temperature distribution in the electrochemical cell is significantly more uniform during operation. Even at high currents, hot spots that could lead to thermal runaway of the cell no longer occur.

[0013] According to an advantageous embodiment of the single electrochemical cell, the arresters can have a plurality of slots extending in the axial direction, in particular parallel slots. Thus, the arresters can be divided into a plurality of narrow arrester lugs, which result in an electrical potential distribution favorable for the ion flow.

[0014] According to an advantageous embodiment of the single electrochemical cell, the arresters can be divided into individual, adjacent arrester lugs of equal width. This allows a uniform, essentially linearized potential distribution across the entire arrester width to be achieved.

[0015] According to an advantageous embodiment of the single electrochemical cell, the width of the arrester lugs can be smaller than their height. This allows a uniform, essentially linearized potential distribution across the entire arrester width to be achieved.

[0016] According to an advantageous embodiment of the single electrochemical cell, at least one of the slots can have a widened portion, particularly a circular portion, at its electrode-side end. This widened portion can prevent potential increases at the transition from the conductor lugs to the electrode surface.

[0017] According to an advantageous embodiment of the single electrochemical cell, the conductor lugs of the first electrodes can each be electrically connected to the first terminal, and the conductor lugs of the second electrodes can each be electrically connected to the second terminal. This results in a particularly favorable electrical connection of the conductor lugs to the terminals, thereby achieving a largely flat potential distribution across the width of the conductor.

[0018] According to an advantageous embodiment of the single electrochemical cell, the conductor lugs of the first electrodes can each be individually electrically connected to the first terminal, and the conductor lugs of the second electrodes can each be individually electrically connected to the second terminal. In this way, a uniform, essentially linearized potential distribution across the entire conductor width can be achieved in a particularly advantageous manner.

[0019] According to an advantageous embodiment of the single electrochemical cell, corresponding conductor tabs of successively arranged first electrodes can be electrically connected, and corresponding conductor tabs of successively arranged second electrodes can be electrically connected. This allows the conductor tabs to be conveniently combined, resulting in favorable potential equalization between the conductors of the various electrodes.

[0020] According to an advantageous embodiment of the single electrochemical cell, electrically connected conductor lugs can each be electrically connected to the first or second terminal connection via a connecting line. This allows a uniform electrical potential to be achieved across the conductor lugs.

[0021] According to a further aspect of the invention, a battery, in particular a high-voltage traction battery of an electrically driven vehicle, with a plurality of individual electrochemical cells connected in series and / or in parallel is proposed.

[0022] The proposed battery can comprise the electrochemical individual cells described above. The favorable electrical potential distribution of the individual cells allows for the construction of a particularly efficient battery with advantageous electrical behavior and increased resistance to thermal runaway of the individual cells.

[0023] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0024] Showing: Fig. 1 shows a schematic structure of an electrochemical single cell for a battery, in particular for a high-voltage traction battery of an electrically powered vehicle, according to an embodiment of the invention; Fig. 2 a course of electrical potential lines around an enlarged view of the arrester of the electrochemical single cell according to Fig. 1; and Fig. 3 shows a schematic structure of a battery, in particular a high-voltage traction battery of an electrically driven vehicle, according to an embodiment of the invention.

[0025] In the figures, identical or similar components are numbered with the same reference numerals. The figures show only examples and are not to be understood as limiting.

[0026] Fig. 1 shows a schematic structure of an electrochemical single cell 10 for a battery 100, in particular for a high-voltage traction battery of an electrically powered vehicle, according to an embodiment of the invention.

[0027] The single electrochemical cell 10 comprises a cell housing 12 with a first terminal connection 22 and a second terminal connection 24, as well as an electrode package 30 arranged in an interior space 14 of the cell housing 12, which has a plurality of first and second electrodes 32, 34, which are each separated by a separator, not shown.

[0028] The prismatic cell housing 12 is formed by a wall 18, a base 20, and a cover 16. The electrode pack 30 and liquid electrolyte 28 are arranged in the interior 14 of the cell housing 12. The electrode pack 30 is electrically insulated from the metallic cell housing 12 by an insulating foil 40. The single electrochemical cell 10 is located on the base of a battery housing 102 of a battery 100.

[0029] The first and second electrodes 32, 34 have conductors 36, 38 that protrude from the first and second electrodes 32, 34 in an axial direction 80. The conductors 36, 38 are electrically connected to the first pole terminal 22 and the second pole terminal 24 by means of electrical connecting lines 26. The conductors 36, 38 are divided by slots 46 extending in the axial direction 80.

[0030] The pole connections 22, 24 can, for example, be designed as contact rivets which are firmly riveted to the cover 16 of the cell housing 12.

[0031] The arresters 36, 38 have a plurality of slots 46, in particular parallel slots 46, and are divided by these into individual arrester lugs 42, 44 of the same width 50 arranged next to one another.

[0032] As with the Fig. 1, a width 50 of the arrester lugs 42, 44 can be smaller than their height 52 in order to accommodate as many arrester lugs 42, 44 as possible over the total width of the arresters 36, 38.

[0033] The slots 46 have an extension 48, in particular a circular extension, at their electrode-side end.

[0034] The conductor lugs 42 of the first electrodes 32 are each electrically connected to the first pole terminal 22 and the conductor lugs 44 of the second electrodes 34 are each electrically connected to the second pole terminal 24.

[0035] It is advantageous if the conductor lugs 42 of the first electrodes 32 are each individually electrically connected to the first terminal connection 22 and the conductor lugs 44 of the second electrodes 34 are each individually electrically connected to the second terminal connection 24. This can be achieved by electrically connecting corresponding conductor lugs 42 of successively arranged first electrodes 32 and also electrically connecting corresponding conductor lugs 44 of successively arranged second electrodes 34. For example, the conductor lugs 42, 44 can be welded together by laser welding or ultrasonic welding. The electrically connected conductor lugs 42, 44 can then, as in Fig. 1, each electrically connected to the first or second pole connection 22, 24 by means of a connecting line 26.

[0036] In Fig. 2 is a course of electrical potential lines 60, 62 around an enlarged view of the arrester 38 of the single electrochemical cell 10 according to Fig. 1 shown.

[0037] Advantageously, the electrical potential 60 is scaled according to the number of arrester lugs 44, thus reducing the profile. Only at a very short distance from the arrester lugs 44 is the potential profile 60 arcuate. Even in the immediate vicinity of the arrester lugs 44, their individual potentials 60 of the respective arrester lug 44 superpose to form a common electrical sum potential 62, which is thereby flattened compared to the potential profile of an unslotted arrester 38. Over large sections of the electrode foil 34, the potential profile 62 remains relatively flat. Therefore, the voltage difference to the neighboring electrode 34 is constant across the electrode width, particularly near the arrester.

[0038] The circular extensions 48 at the electrode-side end of the slots 46 prevent potential increases at the transition from the conductor lugs 44 to the electrode surface.

[0039] The ion flow between an electrode 34 and a neighboring electrode 32 located in front of or behind it is essentially homogeneous. This is due to the fact that the ion flow is driven perpendicular to the electrode surface by the local voltage difference between two neighboring electrodes 32, 34.

[0040] A substantially uniform current density therefore prevails in the active material of the electrodes 32, 34. This results in flatter charging and discharging curves. The electrochemical cell 10 has an increased energy density because the active material is more uniform and thus better utilized. The temperature distribution in the electrochemical cell 10 is significantly more uniform during operation. Even at high currents, hotspots that could lead to thermal runaway of the cell 10 no longer occur.

[0041] In Fig. 3 shows a schematic structure of a battery 100, in particular a high-voltage traction battery of an electrically powered vehicle, according to an embodiment of the invention.

[0042] The battery 100 comprises a plurality of individual electrochemical cells 10 connected in series. The individual cells 10, which are stacked in a battery housing 102, are electrically connected by cell connectors 104. The high-voltage terminals 106, 108 extend out of the battery housing 102. List of reference symbols 10 battery cells 12 cell housings 14 Interior 16 lids 18 wall 20 floor 22-pin connection 24-pin connection 26 connecting line 28 Electrolyte 30 electrode pack 32 first electrode 34 second electrode 36 arresters 38 arresters 40 insulating foil 42 arrester lug 44 arrester lug 46 slot 48 Extension 50 wide arrester lug 52 height of arrester lug 60 individual potential 62 Total potential 80 axial direction 100 batteries 102 Battery housing 104 cell connectors 106 High-voltage connection 108 High-voltage connection 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] WO 2022 / 061187 A1

[0003]

Claims

[1] Electrochemical single cell (10) for a battery, in particular for a high-voltage traction battery of an electrically driven vehicle, comprising at least - a cell housing (12) with a first terminal connection (22) and a second terminal connection (24), - an electrode package (30) arranged in an interior space (14) of the cell housing (12), which has a plurality of first and second electrodes (32, 34), each separated by a separator, wherein the first and second electrodes (32, 34) have conductors (36, 38) projecting from the first and second electrodes (32, 34) in an axial direction (80), wherein the conductors (36, 38) are electrically connected to the first pole terminal (22) and the second pole terminal (24) by means of electrical connecting lines (26), wherein the conductors (36, 38) of at least one of the two electrodes (32, 34) are divided by slots (46) extending in the axial direction (80). [2] Electrochemical single cell according to claim 1, wherein the conductors (36, 38) have a plurality of slots (46) extending in the axial direction (80), in particular parallel slots (46). [3] Single electrochemical cell according to claim 1 or 2, wherein the conductors (36, 38) are divided into individual, juxtaposed conductor lugs (42, 44) of equal width (50). [4] Electrochemical single cell according to one of the preceding claims, wherein a width (50) of the conductor lugs (42, 44) is smaller than their height (52). [5] Electrochemical single cell according to one of the preceding claims, wherein at least one of the slots (46) has an extension (48), in particular a circular extension, at its electrode-side end. [6] Electrochemical single cell according to one of the preceding claims, wherein the conductor lugs (42) of the first electrodes (32) are each electrically connected to the first pole terminal (22) and the conductor lugs (44) of the second electrodes (34) are each electrically connected to the second pole terminal (24). [7] Single electrochemical cell according to one of the preceding claims, wherein the conductor lugs (42) of the first electrodes (32) are each individually electrically connected to the first pole terminal (22) and the conductor lugs (44) of the second electrodes (34) are each individually electrically connected to the second pole terminal (24). [8] Electrochemical single cell according to one of the preceding claims, wherein corresponding conductor lugs (42) of successively arranged first electrodes (32) are electrically connected and wherein corresponding conductor lugs (44) of successively arranged second electrodes (34) are electrically connected. [9] Electrochemical single cell according to claim 8, wherein electrically connected conductor lugs (42, 44) are each electrically connected to the first or second pole terminal (22, 24) by a connecting line (26). [10] Battery (100), in particular a high-voltage traction battery of an electrically driven vehicle with a plurality of electrochemical individual cells (10) connected in series and / or in parallel according to one of the preceding claims.

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