Battery cell and motor vehicle having the battery cell

Abstract

A battery cell (100) has: a housing (101); and a safety valve (10) for venting the housing (101); the safety valve (10) having a tripping element (11) and being designed to open owing to a change in shape from a first state of the tripping element (11) to a second state of the tripping element (11) when a temperature prevailing in the housing (101) rises above a threshold value, in order to allow a medium to flow out of the housing (101).

Description

[0001] 23-3670

[0002] BATTERY CELL AND MOTOR VEHICLE INDICATING THE BATTERY CELL

[0003] The present invention relates to a battery cell, in particular a lithium-ion battery cell, and to a motor vehicle which has the battery cell.

[0004] In the event of thermal runaway of a battery cell, particularly a cylindrical cell, the cell is vented, regardless of its form factor, by a rupture of the battery cell casing. During thermal runaway, hot gases are generated, and the resulting pressure forces the casing to burst, allowing the hot gases to escape from the inside of the battery cell. To prevent an uncontrolled escape of the hot gases, predetermined breaking points, for example, in a "C" shape, are incorporated into the casing to direct the escaping gases in a desired direction. These predetermined breaking points are implemented as indentations in the casing wall; that is, the areas of the casing wall that are expected to rupture first are thinner. The intentionally weakened areas of the battery cell are typically located at the ends of the battery cell, namely at the top or bottom.

[0005] However, the forces acting on the casing, particularly on the area with the predetermined breaking point, are distributed evenly and not always uniformly. The components of the battery cell located inside the casing, such as the electrode coil (jelly roll), the current collector, etc., can influence the distribution of forces in such a way that the pressure causes the predetermined breaking point to tear, rather than the intended breaking point, but rather another area without a predetermined breaking point.

[0006] The variations in battery cell production are relatively large because the coiling or winding of the electrode winding, the voltages of the electrode winding, movement of the electrode winding, and relative positions between the individual components of the battery cell all play a role. For example, applying pressure to the inside of the bottom of the battery cell, which moves during thermal runaway (documented with X-ray videos), can prevent the gases from exerting a force on the notched area or the predetermined breaking point, thus preventing the notch from being stressed locally (as desired). 23-3670

[0007] If all these factors coincide unfavorably, the casing of the battery cell may crack in an undesirable location, which can cause the hot gases to flow onto a neighboring battery cell, ignite it, and ultimately cause a chain reaction.

[0008] One of the objectives of the present invention is to improve a battery cell.

[0009] This problem is solved by the features of the independent patent claims. Further preferred embodiments of the invention are the subject of the dependent patent claims.

[0010] According to a first aspect of the present invention, a battery cell comprises: a housing; and a safety valve for venting the housing; wherein the safety valve has a release element which is configured to open, or be opened, by a change in shape from a first state of the release element to a second state of the release element when a temperature prevailing in the housing rises above a threshold value, in order to allow a medium to flow out of the housing.

[0011] In some designs, this can prevent the escaping medium, in some designs hot gas, from hitting a neighboring battery cell and igniting it, thus improving the safety of the battery cell.

[0012] The temperature threshold can, in some designs, be selected to correspond to an upper range, for example 100°C, of ​​the permissible operating range of the battery cell. Depending on the choice of triggering element, the temperature threshold at which the deformation of the release element is triggered can also be a single temperature value from a range of other values. 23-3670

[0013] The term "vehicle" as used here refers in particular to a passenger car, including all types of motor vehicles, hybrid and battery-powered electric vehicles, as well as vehicles such as sedans, vans, buses, trucks, delivery vans, and the like. In particular, a vehicle may have a wireless communication device or communication equipment for wireless communication with a mobile device.

[0014] Any terms used herein, such as "comprises," "includes," "features," "has," "with," or any other variant thereof, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or features a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent in such method or apparatus.

[0015] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive or and not an exclusive "or". For example, a condition A or B is satisfied by one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0016] The terms "ein" or "eine," as used here, are defined as "one or more." The terms "ein anderer" and "ein Weitere," as well as any other variant thereof, are to be understood as "at least one more."

[0017] The term "plural", as used here, is to be understood in the sense of "two or more".

[0018] The terms "configured" or "set up" to perform a specific function (and their respective variations) are understood within the meaning of the invention to mean that the corresponding device or apparatus already exists in a configuration or setting in which it can perform the function, or at least that it is adjustable—i.e., configurable—so that it can perform the function after appropriate adjustment. Configuration can be achieved, for example, by adjusting parameters of a process sequence or by using switches 23-3670 or similar devices to activate or deactivate functionalities or settings. In particular, the device or apparatus can have several predetermined configurations or operating modes, so that configuration can be performed by selecting one of these configurations or operating modes.

[0019] Preferred embodiments of the invention and their further developments are described below, which, unless expressly excluded, can be combined arbitrarily with each other as well as with the second aspect of the invention and the third aspect of the invention described below.

[0020] In some embodiments, the release element is a bimetallic snap disc with a projection, in some embodiments a pin, extending from a main surface, in some embodiments a center of the main surface, of the bimetallic snap disc, wherein the housing has a housing wall, and the housing wall has a material weakening, the bimetallic snap disc is arranged to cause, upon rise of the temperature prevailing in the housing above the threshold, by deformation, the projection to strike the material weakening in order to open the housing wall.

[0021] In some designs, the projection extends from the main surface, in some designs from a center of the main surface, the bimetallic snap disc, in the direction of the material weakening.

[0022] The operating range of the bimetallic snap disc can, for example, extend from -60°C to 320°C. Such bimetallic snap discs are offered, for instance, by the Austrian company Wurmb GmbH. In some models, the triggering / snapping of the bimetallic snap disc is quick and reliable, and this principle has also proven effective in fuses and switches.

[0023] When the bimetallic snap disc snaps, forces of up to 10,000 N can be generated in some designs, depending on the shape, thickness, and material of the bimetallic snap disc, with the acceleration (of a 23-3670 middle section) of the bimetallic snap disc during the shape change from the first (e.g., convex) state to the second (e.g., concave) state being approximately 30,000 m / s². 2 can amount to.

[0024] In some designs, the projection of the bimetallic snap disc is spaced away from the housing wall in the first state.

[0025] In some designs, the battery cell further comprises an electrode winding and a current collector, which in some designs is disc-shaped, which are received in the housing, wherein the current collector is arranged at an axial end of the electrode winding and the bimetallic snap disc is arranged between the current collector and an axial end of the housing wall.

[0026] The axial end of the housing wall can, for example, be a lid or a bottom of the housing or housing wall, which covers or closes a cylindrical housing part of the housing.

[0027] In some designs, the electrode winding has an axial cavity, with the current collector having an opening that overlaps with an opening of the axial cavity, in some designs is coaxial to the axial opening of the cavity, and in some designs correlates with it.

[0028] In some designs, this allows an additional force to be exerted on the bimetallic snap disc by the medium or hot gas flowing out of the opening of the axial cavity and through the opening of the current collector, in order to further increase the force exerted on the material weakening by the projection.

[0029] In some versions, raised areas are arranged on the inside of the axial end of the housing wall, on which the bimetallic snap disc rests.

[0030] In some designs, the protrusions are arranged in a ring shape, with a recess between each protrusion, and the current collector is located on a side facing the axial end of the housing wall, in some 23-3670

[0031] The design features protrusions formed by deformation, each of which extends into a respective recess.

[0032] In some designs, this allows at least part of the medium or hot gas flowing out through the opening of the axial cavity of the electrode winding to flow radially through the recesses towards the housing wall, thus better distributing the medium exiting the housing.

[0033] In some designs, the protrusions are designed to limit radial movement of the bimetallic snap disc.

[0034] In some embodiments, a central section of the material weakening is arranged in the center of the axial end of the housing wall, with the bimetallic snap disc being designed to cause, upon rising of the temperature prevailing in the housing above the threshold, the deformation to cause the projection to strike the section of the material weakening in order to open the housing wall.

[0035] In some designs, one or more sections of the material weakening extend from the central section at least partially radially towards a circumference of the axial end of the housing wall.

[0036] In some versions, this can make it easier to tear open the casing.

[0037] In some designs, the sections of material weakness can be arranged in a flower-like pattern so that a larger area of ​​the housing wall can rupture more easily, thereby distributing the energy of the gases over a larger area (outside the housing).

[0038] In some designs, the current collector has one or more radially extending slots.

[0039] In some designs, this allows an additional force to be exerted on the bimetallic snap disc by the medium or hot gas passing through the slots and striking the bimetallic snap disc, in order to further increase the force exerted on the material weakening by the projection.

[0040] In some designs, the bimetallic snap disc is curved towards the inside of the housing in the first state, and towards the outside of the housing in the second state.

[0041] According to a second aspect of the present invention, a motor vehicle has a battery cell as described above.

[0042] The features and advantages described in relation to the first aspect of the invention and its advantageous embodiment also apply, at least where technically appropriate, to the second aspect of the invention and its advantageous embodiments, and vice versa.

[0043] Further advantageous developments result from the following description of preferred embodiments. This is shown, in part schematically:

[0044] Fig. 1 shows a cross-sectional view of a battery cell according to one embodiment,

[0045] Fig. 2 shows a cross-sectional view of a safety valve of the battery cell in a first state according to one embodiment.

[0046] Fig. 3 shows a cross-sectional view of the safety valve of the battery cell in a second state according to one embodiment.

[0047] Fig. 4 shows a perspective view from below of a bimetallic snap disc and a current collector of the battery cell according to one embodiment.

[0048] Fig. 5 shows a perspective view of the inside of an axial end of a battery cell housing according to one embodiment.

[0049] Fig. 6 shows an exploded view of a battery cell according to one embodiment, and 23-3670

[0050] Fig. 7 shows a motor vehicle according to one embodiment.

[0051] Fig. 1 schematically shows a cross-sectional view of a battery cell 100, which is designed, for example, as a lithium-ion battery cell, according to one embodiment. The battery cell 100 has a housing 101 with a housing wall 102 in which an electrode arrangement, in some embodiments an electrode winding 130, as well as an electrolyte (not shown), are arranged. Ions can be transferred between the two electrodes, between which a separator is arranged, and between the electrode arrangement.

[0052] Furthermore, in the housing 101, in some embodiments disc-shaped current collectors 160, 170 are arranged between the electrode arrangement or the electrode winding 130 and the axial ends 104, 111 of the housing wall 102, which are connected to current conductors of the electrode arrangement or the electrode winding 130 (not shown) and to a positive terminal 195 or a negative terminal, which is formed by the outside of the housing wall 102, of the battery 100 shown in Fig. 6.

[0053] With reference to Fig. 6, insulations 180, 190 are also provided for electrical insulation between the current collector 170 and the axial end 111 of the housing wall 102 and between the axial end 111 of the housing wall 102 and the positive terminal 195.

[0054] The battery cell 100 further comprises a safety valve 10 for venting the housing 101 or an interior of the housing 101. The safety valve 10 has a release element 11 which is configured to open, upon an increase in the temperature prevailing in the housing 101 or its interior above a threshold value, by a change in shape from a first state of the release element 11, illustrated in Fig. 2, to a second state of the release element 11, illustrated in Fig. 3, in order to allow the outflow of a medium from the housing 101 or its interior.

[0055] In the illustrated embodiment, the release element 11 is a bimetallic snap disc 11, which has a projection 13, in some embodiments a pin, 23-3670 which extends from a main surface 12 facing the axial end 104 of the housing wall 102, in some embodiments bottom or cover, in the illustrated embodiment bottom, of the housing 101, in some embodiments a center of the main surface 12, of the bimetallic snap disc 11 in the direction of the axial end 104 of the housing wall 102.

[0056] The housing wall 102 has a material weakening 103, for example in the form of an indentation, which reduces the material thickness of the housing wall 102 in the area of ​​the material weakening 103 compared to other areas of the housing wall 102. The bimetallic snap disc 11 is designed to cause, when the temperature prevailing in the housing 101 or its interior rises above the threshold, the change in shape or the snapping from the first state to the second state, causing the projection 13 to strike the material weakening 103 (at high speed) in order to tear open the housing wall 102.

[0057] As illustrated in Fig. 2, the projection 13 of the bimetallic snap disc 11 is spaced away from the housing wall 102 in the first state, while in the second state, as illustrated in Fig. 3, the projection 13 of the bimetallic snap disc 11 is in contact with the housing wall 102 and / or passes at least partially through it or through a hole in the housing wall 102 created by the impact. In the first state, the bimetallic snap disc 11 is curved towards an interior of the housing 101, while in the second state, the bimetallic snap disc 11 is curved towards an exterior of the housing 101 or towards the axial end 104 of the housing wall 102.

[0058] With reference to Fig. 1 and Fig. 6, the current collector 160 is arranged at an axial end 132 of the electrode winding 130 facing the axial end 104 of the housing, while the bimetallic snap disc 11 is arranged between the current collector 160 and the axial end 104 of the housing wall 102.

[0059] The electrode winding 130 has an axial cavity 131, and the current collector

[0060] 160 an opening 161 which overlaps or correlates with an opening of the axial cavity 131 23-3670, in some embodiments is coaxial to the opening of the axial cavity 131.

[0061] With reference to Figs. 5 and 6, projections 105 are arranged on an inner surface 109 of the axial end 104 of the housing wall 102, on which the bimetallic snap disc 11, in particular the radially outer areas of the bimetallic snap disc 11, rests or rests.

[0062] As illustrated in Figs. 5 and 6, the protrusions 105 are arranged in a ring shape, with a recess 106 or no protrusion 105 being arranged between the protrusions 105, and the current collector 160 has projections 163 on a side 162 facing the axial end 104 of the housing wall 102, which in the assembled state of the battery cell 100 each project into a respective recess 106.

[0063] The projections 163 can, for example, be formed from the blank of the current collector 160 by forming.

[0064] Preferably, the projections 163 are also designed to limit radial movement of the bimetallic snap disc 10, for example by the projections 163 being in contact with the axial end 104 of the housing wall 102.

[0065] Furthermore, a central section 107 of the material weakening 103 is preferably arranged in the center of the axial end 104 of the housing wall 102, wherein the bimetallic snap disc 11 is configured to cause, when the temperature prevailing in the housing 101 rises above the threshold value, the projection 13 of the bimetallic snap disc 11 to strike the central section 107 of the material weakening 103 by means of a deformation, in order to tear open the housing wall 102.

[0066] As illustrated in Figures 5 and 6, one or more sections 108 of the material weakening 103 extend at least partially radially from the central section 107 towards a circumference of the axial end 104 of the housing wall 102. 23-3670

[0067] With reference to Fig. 6, the current collector 160 preferably has one or more radially extending slots 164. The projections 163 can be formed from the material obtained by forming the slots 164.

[0068] Fig. 7 shows a motor vehicle 200 according to an embodiment which has a battery cell 100 as described above, which is, for example, configured to supply electrical energy to a drive motor of the motor vehicle 200 which is not shown.

Claims

23-3670 REQUIREMENTS 1. Battery cell (100), comprising: a housing (101); and a safety valve (10) for venting the housing (101); wherein the safety valve (10) has a release element (11) which is configured to open, upon an increase of a temperature prevailing in the housing (101) above a threshold value, by a change in shape from a first state of the release element (11) to a second state of the release element (11) in order to allow a medium to escape from the housing (101).

2. Battery cell (100) according to claim 1, wherein the release element (11) comprises a bimetallic snap disc (11) with a projection (13), in particular a mandrel, extending from a main surface (12), in particular a center of the main surface (12), of the bimetallic snap disc (11), the housing (101) comprising a housing wall (102), and the housing wall (102) comprising a material weakening (103), wherein the bimetallic snap disc (11) is configured to cause, upon the rise of the temperature prevailing in the housing (101) above the threshold value, by means of a change in shape, the projection (13) to strike the material weakening (103) in order to open the housing wall (102).

3. Battery cell (100) according to claim 1 or 2, wherein the projection (13) of the bimetallic snap disc (11) is spaced apart from the housing wall (102) in the first state.

4. Battery cell (100) according to claim 2 or 3, further comprising an electrode winding (130) and a current collector (160), in particular a disc-shaped one, which are received in the housing (101), wherein the current collector (160) is arranged at an axial end (132) of the electrode winding (130) and the bimetallic snap disc (11) is arranged between the current collector (160) and an axial end (104) of the housing wall (102). 23-3670 5. Battery cell (100) according to the preceding claim, wherein the electrode winding (130) has an axial cavity (131) and the current collector (160) has an opening (161) which overlaps with an opening of the axial cavity (131), in particular being coaxial to the opening of the axial cavity (131).

6. Battery cell (100) according to one of claims 4 or 5, in which projections (105) are arranged on an inner side (109) of the axial end (104) of the housing wall (102) on which the bimetallic snap disc (11) rests.

7. Battery cell (100) according to the preceding claim, in which the projections (105) are arranged in a ring shape, a respective recess (106) is arranged between the projections (105), and the current collector (160) has projections (163) on a side (162) facing the axial end (104) of the housing wall (102), in particular formed by forming, which each project into a respective recess (106).

8. Battery cell (100) according to the preceding claim, wherein the projections (163) are configured to limit radial movement of the bimetallic snap disc (10).

9. Battery cell (100) according to one of claims 4 to 8, in which a central section (107) of the material weakening (103) is arranged in a center of the axial end (104) of the housing wall (102) and the bimetallic snap disc (11) is configured to cause, upon the rise of the temperature prevailing in the housing (101) above the threshold value, by means of a change in shape, the projection (13) of the bimetallic snap disc (11) to strike the central section (107) of the material weakening (103) in order to open the housing wall (102).

10. Battery cell (100) according to one of claims 4 to 9, in which one or more sections (108) of the material weakening (103) extend at least sectionally radially from the central section (107) in the direction of a circumference of the axial end (104) of the housing wall (102). 23-3670 11. Battery cell (100) according to one of claims 4 to 10, wherein the current collector (160) has one or more radially extending slots (164).

12. Battery cell (100) according to one of the preceding claims, wherein the bimetallic snap disc (11) is curved in the first state towards an interior of the housing (101) and in the second state is curved towards an exterior of the housing (101).

13. Motor vehicle (200) comprising a battery cell (100) according to one of the preceding claims. 14 / 15

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