Electrochemical single cell

Abstract

The invention relates to an electrochemical single cell (100) with an electrically conductive cell housing (30) and at least one electrode assembly (10). The electrode assembly (10) has at least one first current supply (42) with a first polarity and at least one second current supply (43) with a different second polarity. The at least one first current supply (42) has regions (44, 46) located on opposite end faces (17, 19) of the electrode assembly (10) and electrically connected to the cell housing (30) at corresponding, opposite ends (36, 38) of the cell housing (30). The cell housing (30) has at least one first electrical terminal (40) which is electrically connected to the cell housing (30) and to which the at least one first current supply (42) is electrically connected.The cell housing (30) has at least one second electrical terminal (41) which is electrically insulated from the cell housing (30) and to which the at least one second current supply (43) is electrically connected. The at least one second current supply (43) is welded to the second electrical terminal (41).

Description

[0001] The invention relates to an electrochemical single cell with a cell housing and at least one electrode package.

[0002] In a typical design of electrochemical round cells, the cell housing is designed to conduct current, as the electrode coil arranged in the cell housing is connected to a first current lead of a first electrical polarity at the bottom of the cell housing and to a second current lead of a different electrical polarity at a terminal in the cover of the cell housing. Since the cell housing is located in the current path, such a cell typically has a higher internal electrical resistance.

[0003] In another common design, round cells, both power leads are connected to terminals located in the cover of the cell housing. Alternatively, the cover can also be designed as a terminal. Such cells usually have a poorer internal thermal conduction path for dissipating heat from the electrode coil when operated with bottom cooling.

[0004] DE 10 2022 001 865 A1 discloses a prismatic electrochemical single cell with a cell housing comprising a cell stack of at least two electrode stacks, wherein in each of the at least two electrode stacks, a first electrode layer of a first polarity with first contact lugs and a second electrode layer of a second polarity with second contact lugs, each separated by a separator, are stacked one on top of the other in a stacking direction, alternating one on top of the other, wherein the electrode stacks are each closed off by a separator on at least one side in the stacking direction. The electrode layers each have opposite longitudinal sides. The first contact lugs are arranged laterally projecting on one longitudinal side of the first electrode layers, and the second contact lugs are arranged laterally projecting on the opposite longitudinal side of the second electrode layers.The at least two electrode stacks are stacked mirror-inverted in the stacking direction with respect to a transverse plane of the cell stack. The first and second contact lugs are bent toward the transverse plane on end faces of the cell stack. A first collector plate is arranged on a side of the first contact lugs facing away from the cell stack and is electrically connected to the first contact lugs, and a second collector plate is arranged on a side of the second contact lugs facing away from the cell stack and is electrically connected to the second contact lugs. The cell housing has at least one electrical connection pole, which is electrically insulated from the cell housing and to which one of the collector plates is electrically connected.

[0005] In the prismatic cell described in DE 10 2022 001 865 A1, the electrode stack arranged in the cell housing is connected to the base of the cell housing with the first current lead of the first electrical polarity and to the terminal in the cover of the cell housing with the second current lead of the second electrical polarity. Since the cell housing is located in the current path, such a cell also typically has a higher internal resistance.

[0006] JP 2023 098 231 A discloses a secondary battery module comprising a laminated battery formed by laminating a plurality of batteries and storage elements, each comprising a negative electrode current collector and a negative electrode active material layer, a separator or a solid electrolyte, a positive electrode active material layer, and a positive electrode current collector. The current extraction layer is in contact with at least one surface of the outermost layer of the laminated battery. A vertically penetrating small hole is formed in the current extraction layer.

[0007] An object of the invention is to provide an electrochemical single cell with improved electrical and thermal properties.

[0008] The above-mentioned problem is solved by the features of the independent claim.

[0009] Advantageous embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

[0010] According to the invention, an electrochemical single cell with a cell housing and at least one electrode pack is proposed. The cell housing is electrically conductive. The electrode pack has at least one first power supply with a first polarity and at least one second power supply with a different second polarity. The at least one first power supply has regions that are located on opposite end faces of the electrode pack and are electrically connected to the cell housing at corresponding, opposite ends of the cell housing. The cell housing has at least one first electrical connection pole, which is electrically connected to the cell housing and to which the at least one first power supply is electrically connected.The cell housing further comprises at least one second electrical connection terminal, which is electrically insulated from the cell housing and to which the at least one second power supply is electrically connected. The at least one second power supply is welded to the second electrical connection terminal.

[0011] The cell housing is electrically conductive and can be made of aluminum or steel, for example.

[0012] In the proposed single electrochemical cell, the first current lead of the electrode stack is electrically connected to both a terminal in the lid of the cell housing and the base of the cell housing. This conducts part of the current from the first current lead through the cell housing, while the other part of the current flows directly from the electrode stack to the first terminal located in the lid of the cell housing, or vice versa, depending on the polarity and whether the cell is being charged or discharged.

[0013] This combined current path leads to a reduced internal electrical resistance of the entire cell. The current density distribution in the cell casing and in the electrode stack is reduced compared to prior art designs. This allows for a reduction in the foil portion of the electrode stack and the wall thickness of the cell casing, which can lead to an increase in the energy content and performance of the cell, as well as a reduction in cell manufacturing costs. A weight saving is also advantageous.

[0014] Furthermore, the proposed cell reduces temperature rise during load. This eliminates hotspots, i.e., points where significant heat is generated, in the area of ​​the terminals or between the electrode stack and the terminals. This reduces cell aging during operation.

[0015] The current-carrying cell casing has a good thermal conduction path across the bottom of the cell casing.

[0016] The second power supply of the electrode stack is directly electrically connected to the second terminal located in the cover of the cell housing. Short current paths advantageously lead to reduced electrical resistance.

[0017] According to an advantageous embodiment of the single electrochemical cell, the cell housing can have at least one housing body and / or a lid and / or a base, wherein the at least one first current lead can be electrically connected to the housing body and / or to the lid and / or to the base, in particular welded, in particular laser-welded. This advantageously ensures that at least part of the current can flow to or from the first polarity of the electrode stack via the housing body and / or the lid and / or the base. This makes it possible to achieve a lower internal electrical resistance of the cell and better heat dissipation from the cell.

[0018] According to an advantageous embodiment of the single electrochemical cell, the at least one first power supply can be electrically connected to at least one current collector, which is electrically connected to the cell housing and / or to the at least one first electrical connection pole. In particular, the base and / or the cover can be designed as a current collector. The current collector serves to collectively supply or discharge the current from the individual electrode layers of the electrode stack and is predominantly made of solid metal in order to have low electrical resistance.

[0019] According to an advantageous embodiment of the single electrochemical cell, the at least one current collector can be connected to the cell housing, in particular to the housing body and / or the cover, via welded joints. This results in a connection between the current collector and the cell housing with low electrical resistance. Hot spots between the current collector and the cell housing can thus be advantageously avoided.

[0020] According to an advantageous embodiment of the single electrochemical cell, the at least one first power supply can be connected to the base and / or to the at least one current collector via welded joints. This allows for a favorable connection between the electrode stack and the base and / or current collector with low electrical resistance. Hot spots between the electrode stack and the cell housing or current collector can thus be advantageously avoided.

[0021] According to an advantageous embodiment of the single electrochemical cell, the at least one second power supply can be laser-welded to the second electrical terminal. This allows for a favorable connection between the electrode stack and the second terminal with low electrical resistance. Hot spots between the electrode stack and the terminal can thus be advantageously avoided.

[0022] According to an advantageous embodiment of the single electrochemical cell, the cell housing can be cylindrical. Such a round cell with an electrode coil arranged in a cell housing can thus be advantageously realized with lower internal electrical resistance and better heat dissipation from the electrode stack.

[0023] According to an advantageous embodiment of the single electrochemical cell, the cell housing can be prismatic. Such a prismatic or so-called hard-case cell with an electrode stack arranged in a cell housing can thus be advantageously realized with lower internal electrical resistance and better heat dissipation from the electrode stack. The electrode stack can be designed, for example, as an electrode stack. The electrode stack can be a stack of electrode layers as individual electrode sheets or as a so-called Z-fold of electrode layers. Alternatively, one or more flat-pressed electrode coils can be arranged as an electrode stack in the cell housing.

[0024] According to an advantageous embodiment of the single electrochemical cell, the at least one electrode package can be designed as at least one electrode coil, wherein the electrode coil is designed as a coil comprising at least one layer of an electrode layer of the first polarity and an electrode layer of the second polarity, which are separated by a separator. The first current lead can be formed at least partially from the electrode layer of the first polarity, and the second current lead can be formed at least partially from the electrode layer of the second polarity. The first current lead of the electrode coil can advantageously comprise a plurality of regions located on opposite end faces of the electrode coil and electrically connected to the base of the cell housing and to a current collector and / or a first terminal on the cover of the cell housing.The second power supply can, for example, be electrically connected directly to the second connection pole on the cover of the cell housing.

[0025] According to an advantageous embodiment of the single electrochemical cell, the at least one electrode package can be designed as at least one electrode stack, wherein the electrode stack is formed from alternating electrode layers of the first polarity and electrode layers of the second polarity, each separated by a separator. The electrode layers can each have contact tabs on the end faces of the electrode package, wherein the first power supply can be formed from contact tabs of electrode layers of the first polarity, and the second power supply can be formed from contact tabs of electrode layers of the second polarity.The first power supply of the electrode stack can advantageously have a plurality of regions, which are located, for example, on opposite end faces of the electrode stack and are electrically connected, for example, to the bottom of the cell housing and to a current collector and / or a first terminal on the cover of the cell housing. The second power supply can, for example, be electrically connected directly to the second terminal on the cover of the cell housing.

[0026] 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.

[0027] Showing: Fig. 1 a longitudinal section through an electrochemical single cell as a round cell according to an embodiment of the invention; Fig. 2 shows a longitudinal section through an electrochemical single cell as a prismatic cell according to a further embodiment of the invention; Fig. 3 a terminal of the prismatic cell according to Fig. 2 in a plan view; and Fig. 4 an insulator of the prismatic cell according to Fig. 2 in a top view.

[0028] 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.

[0029] Fig. Figure 1 shows a longitudinal section through an electrochemical single cell 100 as a round cell according to one embodiment of the invention. The round cell is rotationally symmetrical about the longitudinal axis 80. The cell housing 30 is cylindrical.

[0030] The single electrochemical cell 100 has a cell housing 30 in which an electrode package 10 is arranged in the form of an electrode coil 12. The cell housing 30 is electrically conductive, for example, made of aluminum or steel.

[0031] The electrode coil 12 is wound around a winding core 14 from at least one electrode layer of a first polarity and one electrode layer of a different second polarity, which are separated by a separator. The electrode coil 12 has at least one first power supply 42 with the first polarity and at least one second power supply 43 with the second polarity. The first power supply 42 is formed at least partially from the electrode layer of the first polarity, and the second power supply 43 is formed at least partially from the electrode layer of the second polarity. The two power supplies 42, 43 are not visible in the longitudinal section because they are located in the end faces 17, 19 of the electrode coil 12.

[0032] The at least one first power supply 42 has regions 44, 46 which are present on opposite end faces 17, 19 of the electrode package 10 and are electrically connected to the cell housing 30 at corresponding, opposite ends 36, 38 of the cell housing 30.

[0033] The cell housing 30 has at least one first electrical connection pole 40, which is electrically connected to the cell housing 30 and to which the at least one first power supply 42 is electrically connected. The first electrical connection 40 can, for example, be semicircular around the longitudinal axis 80 or circular as a ring.

[0034] The cell housing 30 further comprises at least one second electrical connection pole 41, which is electrically insulated from the cell housing 30 by an insulator 56 and to which the at least one second power supply 43 is electrically connected. The second electrical connection 41 can, for example, be cylindrical and arranged along the longitudinal axis 80.

[0035] The cell housing 30 comprises a housing body 39, the so-called cell cup, a lid 31, and a base 32. The base 32 can also be formed integrally with the housing body 39 if the housing body 39 is, for example, extruded or deep-drawn.

[0036] The first power supply 42 can, for example, be electrically connected to the housing body 39 and / or to the cover 31 and / or to the base 32, in particular welded, in particular laser welded.

[0037] In the Fig. 1, the region 44 of the first current lead 42 is electrically connected to the current collector 34 on one end face 17, while the region 46 of the first current lead 42 is electrically connected to the base 32 as current collector 33 or to the additional current collectors 35, which can be formed in a ring around the longitudinal axis 80, on the other end face 19.

[0038] The current collector 34 is designed as a first electrical connection pole 40 and is connected to the cell housing 30, in particular to the housing body 39, via lateral welded joints 22. The current collector 34 can also be connected to the cover 31 via additional welded joints 24.

[0039] The base 32 can be designed as a current collector 33.

[0040] The first current supply 42 can be connected directly to the base 32 via welded connections 26 and to the additional current collector 35 via welded connections 28.

[0041] The second power supply 43 can be welded, in particular laser welded, to the second electrical connection pole 41.

[0042] The electrical connection poles 40, 41 are electrically connected to cell connectors 52, 54.

[0043] At the Fig. In the round cell shown in Figure 1, the first terminal 40 is designed as the anode (negative pole) and the second terminal 41 as the cathode (positive pole). In a further embodiment of the single electrochemical cell, the first terminal 40 can be designed as the cathode (positive pole) and the second terminal 41 as the anode (negative pole).

[0044] Current paths are represented by solid arrows. A portion of the current from the first current lead 42 with the first electrical polarity can therefore flow from the electrode winding 12 via the region 46 directly into the base 32 and / or via the additional current collector 35 into the base 32 and flow via the wall of the housing body 39 to the cell connector 52. The other portion of the current from the first current lead 42 can flow via the region 44 into the first terminal 40, designed as a current collector 34, and from there into the cell connector 52.

[0045] The current of the second power supply 43 with the second electrical polarity can flow directly into the electrode coil 12 via the second electrical connection 41.

[0046] Since the current from the first power supply 42 flows evenly across the cell housing 30, the heat generated in the electrode coil 12 is also better distributed. The heat flow 70, represented by dashed arrows, can thus advantageously flow from the electrode coil 12 into cooling elements 60, 62, which are arranged on the wall of the housing body 39 at the bottom 32. The cooling elements 60, 62 can be, for example, cooling plates or cooling coils.

[0047] The illustrated single cell 100 also has an improved internal electrical resistance compared to a connection of the electrode package 10 to the terminal poles 40, 41 according to the prior art.

[0048] Fig. Figure 2 shows a longitudinal section through an electrochemical single cell 100 as a prismatic cell according to another embodiment of the invention. The cell housing 30 has a prismatic design.

[0049] The cell housing 30 has a housing body 39, a cover 31, and a base 32. The cover 31 or base 32 can also be formed integrally with the housing body 39, for example, if the housing body 39 is extruded or deep-drawn.

[0050] The electrode package 10 is designed as an electrode stack 20, wherein the electrode stack 20 is formed from alternately arranged electrode layers of individual electrode sheets of the first polarity and electrode layers of individual electrode sheets of the second polarity, which are each separated by a sheet of a separator.

[0051] The electrode layers each have contact lugs 16, 18 on the end faces 17, 19 of the electrode package 10, wherein the first current lead 42 is formed from contact lugs 16 of electrode layers of the first polarity and the second current lead 43 is formed from contact lugs 18 of electrode layers of the second polarity.

[0052] The region 46 of the first power supply 42 is electrically connected to the base 32 of the cell housing 30, which is designed as a current collector 33 for this purpose, while the region 44 of the first power supply 42 is electrically connected to another current collector 34, which in turn is electrically connected to current feedthroughs 50. The current feedthroughs 50 are also electrically connected to the cell housing 30 and to a first terminal 40, which in turn can be contacted with cell connectors (not shown).

[0053] The current path, again shown with arrows, runs partly via the current feedthroughs 50 and the contact lugs 18 into the electrode stack 20. The other part of the current path runs from the first connection pole 40 via the housing body 39 into the base 32 and from there via the contact lugs 18 into the electrode stack 20.

[0054] The current path of the second current lead 43 runs from the electrode stack 20 via the contact tabs 16 into a current collector 37, which is also electrically connected to current feedthroughs 51. However, these current feedthroughs 51 are electrically insulated from the cell housing 30 by insulators 56, 58.

[0055] The current feedthroughs 51 are electrically connected to one another outside the cell housing 30 via the second connection pole 41.

[0056] The second electrical connection pole 41 and the insulator 58 are provided with the corresponding recesses 48 for the current feedthroughs 51 in the Fig. 3 and Fig. 4 is shown as an example.

[0057] At the Fig. 2 is, in contrast to the prismatic cell shown in Fig. 1, the first connection pole 40 is designed as a cathode (positive pole) and the second connection pole 41 as an anode (negative pole).

[0058] The design of the two terminals 40, 41 and their position on the cell housing 30 are only examples. Other arrangements of the terminals 40, 41 are also possible.

[0059] Since this, as with the one in Fig. In the embodiment shown in Figure 1, of a single electrochemical cell 100, the current from the first power supply 42 flows evenly across the cell housing 30, which also improves heat distribution in the electrode stack 10. The heat can thus advantageously flow from the electrode stack 10 into the wall of the housing body 39 and the base 32, and from there, dissipate via cooling elements (not shown). Cooling elements can be, for example, cooling plates or cooling coils.

[0060] The illustrated single cell 100 also has an improved internal electrical resistance compared to a connection of the electrode package 10 to the terminal poles 40, 41 according to the prior art.

[0061] The features and advantages described herein with respect to one embodiment of a single electrochemical cell may also relate to another embodiment described herein and vice versa. List of reference symbols 10 electrode pack 12 electrode coils 14 winding core 16 Contact flag 18 Contact flag 20 electrode stacks 22 Welded joint 24 Welded joint 26 Welded joint 28 Welded joint 30 cell casings 31 lids 32 Floor 33 Current collector 34 Current collector 35 Current collector 36 End 37 Current collector 38 End 40 connection pole 41 connection pole 42 Power supply 43 Power supply 44 Area 46 Area 48 recess 50 power feedthrough 51 Power feedthrough 52 cell connectors 54 cell connectors 56 Insulator 58 Insulator 60 cooling element 62 cooling element 70 Heat flow 80 Longitudinal axis 100 single cells

Claims

[1] Electrochemical single cell (100) with a cell housing (30) and at least one electrode package (10), wherein the cell housing (30) is electrically conductive, wherein the electrode package (10) has at least one first current lead (42) with a first polarity and at least one second current lead (43) with a different second polarity, wherein the at least one first power supply (42) has regions (44, 46) which are located on mutually opposite end faces (17, 19) of the electrode package (10) and are electrically connected to the cell housing (30) at corresponding, mutually opposite ends (36, 38) of the cell housing (30), wherein the cell housing (30) has at least one first electrical connection pole (40) which is electrically connected to the cell housing (30) and to which the at least one first power supply (42) is electrically connected, wherein the cell housing (30) has at least one second electrical connection pole (41) which is electrically insulated from the cell housing (30) and to which the at least one second power supply (43) is electrically connected, and wherein the at least one second power supply (43) is welded to the second electrical connection pole (41). [2] Electrochemical single cell according to claim 1, wherein the cell housing (30) has at least one housing body (39) and / or a cover (31) and / or a base (32), wherein the at least one first power supply lead (42) is electrically connected, in particular welded, in particular laser-welded, to the housing body (39) and / or to the cover (31) and / or to the base (32). [3] Electrochemical single cell according to claim 1 or 2, wherein the at least one first current supply (42) is electrically connected to at least one current collector (33, 34, 35) which is electrically connected to the cell housing (30) and / or to the at least one first electrical connection pole (40), in particular wherein the base (32) and / or the cover (31) is designed as a current collector (33, 34). [4] Electrochemical single cell according to claim 3, wherein the at least one current collector (33, 34, 35) is connected to the cell housing (30), in particular to the housing body (39) and / or the cover (31) via welded joints (22, 24). [5] Electrochemical single cell according to claim 3 or 4, wherein the at least one first current lead (42) is connected to the base (32) and / or to the at least one current collector (33, 35) via welded joints (26, 28). [6] Electrochemical single cell according to one of the preceding claims, wherein the at least one second power supply (43) is laser-welded to the second electrical connection pole (41). [7] Electrochemical single cell according to one of the preceding claims, wherein the cell housing (30) is cylindrical. [8] Electrochemical single cell according to one of claims 1 to 6, wherein the cell housing (30) is prismatic. [9] Electrochemical single cell according to one of the preceding claims, wherein the at least one electrode package (10) is designed as at least one electrode coil (12), wherein the electrode coil (12) is designed as a coil of at least one layer of an electrode layer of the first polarity and an electrode layer of the second polarity, which are separated by a separator, wherein the first current lead (42) is formed at least partially from the electrode layer of the first polarity and wherein the second current lead (43) is formed at least partially from the electrode layer of the second polarity. [10] Electrochemical single cell according to one of claims 1 to 8, wherein the at least one electrode package (10) is designed as at least one electrode stack (20), wherein the electrode stack (20) is formed from alternatingly arranged electrode layers of the first polarity and electrode layers of the second polarity, which are each separated by a separator, wherein the electrode layers each have contact lugs (16, 18) on the end faces (17, 19) of the electrode package (10), wherein the first current lead (42) is formed from contact lugs (16) of electrode layers of the first polarity and wherein the second current lead (43) is formed from contact lugs (18) of electrode layers of the second polarity.

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