Traction battery wound cell

Abstract

Traction battery wound cell (10) with an externally cylindrical winding core (20), a foil composite (300) wound onto the winding core (20), which is formed by an anode foil (31), a cathode foil (32) and two insulator foils (341,342), and a fluid-tight cell housing (40) which encloses the film composite (300) in a fluid-tight manner, wherein the winding core (20) is formed by a hollow cylindrical anode tube (22) and a hollow cylindrical cathode tube (24), which are connected by an electrically non-conductive separating ring body (26) to form a fluid-tight axial cooling channel (29) for a cooling liquid, and wherein the cathode foil (32) is electrically connected to the cathode tube (24) and the anode foil (31) is electrically connected to the anode tube (22).

Description

[0001] The invention relates to a traction battery wound cell having an outer cylindrical winding core onto which a foil composite is wound spirally.

[0002] A typical traction battery for a passenger car currently has a capacity in the order of 100 kWh, making the traction battery a major cost factor in the manufacture of a motor vehicle. Wound-type battery cells are known from CN 1 01 393 973 A and CN 2 02 749 463 U, are generally inexpensive to manufacture, and are therefore well suited for automotive traction batteries. High electrical currents flow during both rapid charging and discharging while driving, requiring powerful cooling of the traction battery. Even with active liquid cooling of the fluid-tight housing of a traction battery wound cell, the center of the wound cell is cooled only relatively slowly, so that the maximum power during charging and discharging is very limited.

[0003] DE 10 2011 010 664 A1 and WO 2022 / 063 632 A1 disclose a cylindrical traction battery wound cell whose cell core is formed by a hollow cylindrical tube, allowing the center of the battery cell to be actively liquid-cooled via the tube. The terminal anode and the terminal cathode of the traction battery wound cell are formed by separate annular bodies surrounding the tube.

[0004] The object of the invention is to create a traction battery wound cell with a simple structure.

[0005] This object is achieved according to the invention with a traction battery wound cell having the features of claim 1.

[0006] The traction battery wound cell according to the invention has an outer cylindrical winding core onto which a foil composite is wound, preferably spirally wound. The foil composite is formed by an anode foil, a cathode foil, and two insulator foils, each of which is located between an anode foil and an adjacent cathode foil. Thus, viewed in the radial direction, a plurality of anode foil layers and cathode foil layers lie one above the other. A typical capacity of such a traction battery wound cell is in the range of a few watt-hours.

[0007] The entire cylindrical foil composite is enclosed in a fluid-tight cell housing. This allows the traction battery wound cell to be cooled externally, for example, with a suitable electrically non-conductive coolant, such as cooling oil.

[0008] The winding core is formed by a hollow cylindrical, electrically conductive anode tube and a hollow cylindrical, electrically conductive cathode tube. The two tubes have approximately the same outer diameter and the same inner diameter. The cathode tube and the anode tube are axially aligned and connected to each other by an electrically non-conductive separating ring body to form a fluid-tight axial cooling channel. The cathode foil is electrically connected only to the cathode tube, and the anode foil is electrically connected only to the anode tube. The electrical connection of the traction battery winding cell to its electrical periphery can therefore be established directly via the cathode tube and the anode tube, respectively. Separate components of the traction battery winding cell are not required for this purpose.

[0009] Preferably, the cell housing is designed entirely as an electrical insulator, whereby contact protection is easily implemented, particularly in the event of an electrical defect within the traction battery winding cell.

[0010] The cell housing preferably has a housing cylinder formed from a plastic film, which is particularly preferably a shrink tube. This allows the traction battery wound cell to be manufactured very easily and inexpensively.

[0011] Preferably, the anode tube, on the one hand, and the cathode tube, on the other, each protrude axially from the cell housing. This simplifies the electrical connection of the traction battery wound cell and can, for example, be achieved using a simple contact terminal that can directly contact the tube stub protruding from the cell housing.

[0012] Preferably, the anode foil and the cathode foil are each made of aluminum, wherein the annular space defined by the cell housing and the winding core is filled with an electrolyte liquid.

[0013] An embodiment of the invention is explained in more detail below with reference to the drawings. They show: Fig. 1 a schematic longitudinal section of a traction battery wound cell with a wound core formed by a cathode tube and an anode tube and wound with a foil composite, Fig. 2 an enlarged view of a detail II of the traction battery wound cell with the anode tube leading out of the cell housing, and Fig. 3 an enlarged view of the anode tube of the Fig. 1 and Fig. 2 when wrapping with the film composite.

[0014] In the Fig. Figure 1 shows a schematic longitudinal section of a traction battery wound cell 10 installed in a motor vehicle with an electric traction drive as part of a traction battery. Typically, several thousand such traction battery wound cells 10 are physically and electrically combined to form the traction battery.

[0015] The essentially externally cylindrical traction battery wound cell 10 has an externally cylindrical wound core 20 formed by a hollow cylindrical anode tube 22, a hollow cylindrical cathode tube 24, and an electrically non-conductive separating ring body 26, which connects the anode tube 22 and the cathode tube 24 in a fluid-tight manner and electrically separates them. The separating ring body 26, which is approximately T-shaped in cross-section, is formed by a separating ring plastic body 26' and is adhesively bonded in a fluid-tight manner to the adjacent anode tube 22 and the oppositely adjacent cathode tube 24. The wound core 20 thus forms a fluid-tight axial cooling channel 29 for a cooling liquid, for example, a cooling oil. The anode tube 22 and the cathode tube 24 each consist of an electrically conductive stainless metal tube 22', 24'. The winding core 20 is rotationally symmetrical with respect to a cell axial A.

[0016] A film composite 300 is wound spirally onto the outer cylindrical winding core 20 to form a plurality of layers, in the present embodiment to a total of five film composite layers 301 - 305, which together form a layer assembly 30. A film composite 300 consists, as shown in the Fig. 3, of a first insulator foil 341, an anode foil 31, a second insulator foil 342 and a cathode foil 32. The four foils of the foil composite 300 are each glued to one another, so that the foil composite 300 as a whole is wound spirally onto the winding core 20, as shown in the Fig. 3, which shows the winding cell 10' during the winding process step.

[0017] A flag-like and radially inner end section 31' of the anode foil 31 is electrically conductively connected exclusively to the anode tube 22 via an electrical connection C22, as shown in Fig.3. In an analogous manner, a corresponding radially inner end portion of the cathode foil 32 is electrically conductively connected exclusively to the cathode tube 24 via an electrical connection C24.

[0018] The traction battery wound cell 10 has an electrically non-conductive cell housing 40 formed from a substantially cylindrical plastic housing cylinder 42 and two housing annular discs 44, 45, which, together with the fluid-tight winding core 20, form a fluid-tight annular space for the entire layer assembly 30. The annular disc-shaped annular discs 44, 45 each consist of a plastic annular body 44', 45'. The plastic housing cylinder 42 is formed from a shrink-wrapped plastic film (42').

[0019] An anodic tube stub 22" of the anode tube 22 on the one hand and a cathodic tube stub 24" of the cathode tube 24 on the other hand each protrude axially from the cell housing 40 and can be electrically contacted in a simple manner, for example by a contact terminal.

Claims

[1] Traction battery wound cell (10) with an externally cylindrical winding core (20), a foil composite (300) wound onto the winding core (20), which is formed by an anode foil (31), a cathode foil (32) and two insulator foils (341,342), and a fluid-tight cell housing (40) which encloses the film composite (300) in a fluid-tight manner, wherein the winding core (20) is formed by a hollow cylindrical anode tube (22) and a hollow cylindrical cathode tube (24), which are connected by an electrically non-conductive separating ring body (26) to form a fluid-tight axial cooling channel (29) for a cooling liquid, and wherein the cathode foil (32) is electrically connected to the cathode tube (24) and the anode foil (31) is electrically connected to the anode tube (22). [2] Traction battery wound cell (10) according to claim 1, wherein the cell housing (40) is designed as an electrical insulator. [3] Traction battery wound cell (10) according to one of the preceding claims, wherein the anode tube (22) and the cathode tube (24) each protrude axially from the cell housing (40). [4] Traction battery wound cell (10) according to one of the preceding claims, wherein the anode foil (31), the cathode foil (32) and the two insulator foils (341,342) are glued together to form the foil composite (300). [5] Traction battery wound cell (10) according to one of the preceding claims, wherein the anode foil (31) and the cathode foil (32) consist of aluminum and wherein the annular space defined by the cell housing (40) and the winding core (20) is filled with an electrolyte liquid. [6] Traction battery wound cell (10) according to one of the preceding claims, wherein the cell housing (40) has a housing cylinder (42) which is formed by a plastic film (42'), which is particularly preferably a shrink tube.

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