KR20170020275A - Electrode unit for a battery cell, battery cell and method for operating the battery cell - Google Patents

Abstract

The present invention relates to an electrode unit (10) comprising: an anode (21) which includes an anode active material (41) and an anode current conductor (31); a cathode (22) which includes a cathode active material (42) and a cathode conductor (32); and a separator plate (18) which separates the anode (21) from the cathode (22). According to the present invention, the anode active material (41) exists as strip-shaped anode segments (71, 72) and/or the cathode active material (42) exists as strip-shaped cathode segments (81, 82), and the separator plate (18) is formed in a continuous manner. The present invention relates not only to a batter cell comprising the above electrode unit (10), but also to a battery cell operation method, according to which a balancing current flowing from one anode segment (71, 72) to an adjacent anode segment (71, 72) is detected, and/or a balancing current flowing from one cathode segment (81, 82) to an adjacent cathode segment (81, 82) is detected.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrode unit for a battery cell, a battery cell, and a method of operating the battery cell. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to an electrode unit for a battery cell including an anode, a cathode, and a separator. The present invention also relates to a battery cell including at least one electrode unit, and a method of operating the battery cell.

The electrical energy can be stored by the batteries. Batteries convert chemical reaction energy into electrical energy. In this case, primary batteries and secondary batteries are distinguished. Primary batteries can only be operated once, while secondary batteries, also called accumulators, can be recharged. In this case, one battery includes one or a plurality of battery cells.

In the accumulator, so-called lithium ion battery cells are used. The lithium ion battery cells are particularly characterized by high energy density and low self-discharge. Lithium-ion battery cells are used particularly in automobiles, particularly in electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs).

Lithium ion battery cells include an anode electrode, also referred to as a cathode, and a cathode electrode, also referred to as an anode. The cathode and the anode each include one current conductor on which the active material is coated. The active material for the cathode is, for example, a metal oxide. The active material for the anode is, for example, graphite. However, silicon is also used as the active material for the anode.

Lithium atoms are incorporated in the active material of the anode. During operation of the battery cell, i. E. During the discharge process, electrons in the external electrical circuit flow from the anode toward the cathode. Inside the battery cell, lithium ions migrate from the anode toward the cathode during the discharge process. In this case, the lithium ions flow out in a reversible manner from the active material of the anode, which is also referred to as delithiation. During the charging process of the battery cell, lithium ions migrate from the cathode toward the anode. In this case, lithium ions are incorporated again into the active material of the anode in a reversible manner, which is also referred to as lithiation.

The electrodes of the battery cell are formed in a film type, and a separator separating the anode from the cathode is wound with the interlayer interposed therebetween to form one electrode coil. The electrode coil may also be referred to as a jelly-roll. Further, the electrodes may be stacked to form one electrode stack, or another electrode unit may be formed.

The two electrodes of the electrode unit are electrically connected to the poles of the battery cell, also referred to as terminals, by collectors. One battery cell generally includes one or a plurality of electrode units. The electrodes and the separator are surrounded by a generally liquid electrolyte. The electrolyte is conductive to the lithium ions and allows migration of lithium ions between the electrodes.

The battery cell also includes a cell housing made of, for example, aluminum. In the case of a structural shape called a prismatic battery cell, the cell housing is formed in a prismatic shape, in particular a rectangular parallelepiped shape, and is formed with pressure resistance. In this case, the terminals are disposed outside the cell housing. After connection of the terminals and the electrodes, the electrolyte is filled into the cell housing. In particular, additional structural features distinguished in the configuration of the cell housing are widely available, such as a round cell having a cylindrical cell housing and a pouch cell having a square cell housing without mechanical pressure resistance .

In today's common configurations of battery systems, a plurality of battery cells are integrated to form one battery module. The plurality of battery modules form one battery system further comprising a battery module and a control unit for monitoring and controlling the battery cells.

A battery cell of this type, comprising an electrode unit with an anode and a cathode separated by a separator, is disclosed, for example, in DE 10 2013 200 714 A1.

A battery comprising a plurality of battery cells and a method for defect detection in battery cells is disclosed in US 2013/0113495 A1.

US 2011/0110183169 A1 discloses a battery cell comprising a plurality of electrode units disposed in a common housing.

An object of the present invention is to provide an electrode unit for a battery cell including an anode, a cathode and a separator, a battery cell including the electrode unit of the above type, and a method for operating the battery cell.

According to the present invention, there is provided an anode comprising an anode active material and an anode current collector, a cathode having a cathode active material and a cathode current collector, and a separator separating the anode from the cathode, An electrode unit for a battery cell is proposed.

In this case, according to the present invention, the anode active material is present in the form of strip-shaped anode segments, and / or the cathode active material is present in the form of strip-shaped cathode segments, and the separator plate is formed in a continuous manner.

According to one preferred embodiment of the invention, the anode current conductor is formed in the following manner, and / or the cathode current conductor is formed in a continuous manner.

According to another preferred embodiment of the present invention, the anode current conductor is in the form of strip-like anode conductor segments, and / or the cathode current conductor is in the form of strip-shaped cathode conductor segments.

In this case, preferably, the anode conductor segments of the anode current conductor are connected to one another via connection weg, and / or the cathode conductor segments of the cathode current conductor are connected to one another through the connecting webs.

Further, according to the present invention, a battery cell including at least one electrode unit according to the present invention is also proposed.

Further, according to the present invention, a method for operating a battery cell according to the present invention is also proposed. In this case, a balancing current flowing from one anode segment toward the neighboring anode segment is detected, and / or a balancing current flowing from one cathode segment to the neighboring cathode segment is detected.

According to one preferred embodiment of the method of the present application, the magnetic field produced by the balancing current flowing through the anode current conductor formed in the following manner and / or flowing through the cathode current conductor formed in the following manner is measured.

According to another preferred embodiment of the method of the present application, a magnetic field generated by the balancing current flowing through the connecting web connecting the anode conductor segments of the anode current conductor to each other and / or connecting the cathode conductor segments of the cathode current conductor to each other .

According to another preferred embodiment of the method of the present application, the voltage applied to the connecting web connecting the anode conductor segments of the anode current conductor to each other and / or the cathode conductor segments of the cathode current conductor to each other is measured, Is generated by the balancing current flowing through the connecting web.

The battery according to the present invention is preferably used in a fixed energy storage device, in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV), or in a consumer electronics product. Consumer electronics means especially mobile phones, tablet PCs or notebooks.

The electronic unit formed in accordance with the present invention allows relatively simple defect detection. When the electrode unit is operating normally, current flows through all anode segments and through all cathode segments in the same direction. If the electrode unit is defective, the defective anode segment or the defective cathode segment exhibits altered electrical properties. As a result, a balancing current may flow, for example, from the defective anode segment toward the neighboring anode segment, or from the defective cathode segment toward the neighboring cathode segment. If there is no defect in the electrode unit, there is no balancing current, or there is only a balancing current that is only small and varies slowly in time.

The balancing current of this type is therefore an indicator of a defect in the battery cell that can result from heating of the battery cell to exceeding the critical temperature. In this case, an exothermic reaction of the battery cell, also referred to as "thermal runaway" As a result, a fire or explosion of the battery cell may also occur. When the defects are timely detected by detecting the balancing current in the electrode unit, the battery cell can be deactivated in a timely manner, and / or additional safety measures can be carried out, in particular discharge of the battery cell.

The detection of the balancing current flowing in the other direction through the anode segments and the normal currents flowing through the cathode segments can be performed relatively simply. Particularly, the balancing current generates a magnetic field having a different direction from the magnetic fields generated by the normal currents. Whereby defects on the electrode unit are detected in a timely and reliable manner.

The distinction between a defective battery cell and a non-defective battery cell can be performed, for example, via an electronic device in an electronic module device, for example, on an integration tier in or on a battery cell or on a relatively higher level. For example, if the balancing current and associated measurement variables change rapidly over time, or if the variables rise above a standard threshold for a defective battery cell, the battery cell is classified as defective.

In addition to cell monitoring during operation of the battery cell as an energy storage device in a battery system, it is also possible to use the method according to the invention for cell defect inspection after manufacture or during transport or storage.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention are described in more detail in accordance with the drawings and the following description.

1 is a schematic view showing a battery cell.
FIG. 2 is a perspective view showing an electrode unit of the battery cell of FIG. 1. FIG.
3 is a schematic cross-sectional view showing the electrode unit of Fig. 2 according to the first embodiment.
Fig. 4 is a schematic sectional view showing the electrode unit of Fig. 2 according to the second embodiment. Fig.
Fig. 5 is a schematic plan view showing the electrode unit of Fig. 2 according to the third embodiment. Fig.
6 is a schematic diagram illustrating a battery cell including an integrated sensor.

In the following description of the embodiments of the present invention, the same or similar elements are denoted by the same reference numerals, and the repetitive description of the elements in each case is omitted. The drawings show only the subject matter of the present invention schematically.

The battery cell 2 is schematically shown in Fig. The battery cell 2 includes a cell housing 3 formed in a rectangular parallelepiped shape in this case. The cell housing 3 is realized in this case electrically conductive and is made, for example, of aluminum. In addition, the cell housing 3 may be made of an electrically insulating material, such as plastic, and / or may be realized in another structural form, for example as a circular cell or a pouch cell.

The battery cell 2 includes a negative electrode terminal 11 and a positive electrode terminal 12. Through the terminals 11 and 12, the voltage supplied from the battery cell 2 can be tapped. Also, the battery cell 2 may be charged through the terminals 11, 12. The terminals 11 and 12 are spaced apart from each other and disposed on the cover surface of the prismatic cell housing 3. [

In the cell housing 3 of the battery cell 2, an electrode unit 10 realized as an electrode coil in this case is disposed. The electrode unit 10 includes two electrodes, that is, an anode 21 and a cathode 22. The anode 21 and the cathode 22 are each realized as a film type, and the separator plate 18 is wound with the intermediate layer interposed therebetween to form an electrode coil. It is also conceivable that a plurality of electrode units 10 are provided in the cell housing 3. The electrode unit 10 can be realized, for example, as an electrode stack instead of being realized as an electrode coil.

The anode 21 comprises an anode active material 41 realized as a film type. The anode active material 41 includes, for example, graphite or silicon or an alloy containing these materials as a base material. In addition, the anode 21 further includes an anode current conductor 31 likewise formed in a film type. The anode active material 41 and the anode current conductor 31 are arranged in parallel to each other and connected to each other.

The anode current conductor 31 is realized as electrically conductive and is made of metal, e.g., copper. The anode current conductor 31 is electrically connected to the cathode terminal 11 of the battery cell 2 by a collector 52. [

The cathode 22 comprises a cathode active material 42 realized as a film type. The cathode active material 42 contains, for example, a metal oxide as a base material. In addition, the cathode 22 further includes a cathode current conductor 32 likewise formed in film type. The cathode active material 42 and the cathode current conductor 32 are arranged side by side flat and connected to each other.

The cathode current conductor 32 is realized as electrically conductive and is made of metal, for example aluminum. The cathode current conductor 32 is electrically connected to the cathode terminal 12 of the battery cell 2 by a collector 52. [

The anode 21 and the cathode 22 are separated from each other through a separator plate 18. The separator plate 18 is likewise formed of a film type. The separator 18 is formed of an electrically insulating material, but is formed to be ion conductive, that is, to be permeable to lithium ions.

The cell housing 3 of the battery cell 2 is filled with an electrolyte 15, such as a liquid electrolyte, or with a polymer electrolyte. In this case, the electrolyte 15 surrounds the anode 21, the cathode 22 and the separator plate 18. The electrolyte 15 is also ion conductive.

2, the electrode unit 10 of the battery cell 2 of Fig. 1 is shown in a perspective view. In this case, the electrode unit 10 is realized as an electrode coil in this case, as already mentioned. The anode 21, the cathode 22 not visible in the figure, and the separator 18 are wound around the winding axis A to form an electrode coil.

The anode 21 includes an anode current conductor 31 and an anode active material 41. In this case, the anode active material 41 comprises a first strip-shaped anode segment 71 and at least one second strip-shaped anode segment 72. The strip-shaped anode segments 71 and 72 are disposed on the anode current conductor 31 in parallel with each other. The strip-shaped anode segments 71 and 72 are separated from each other. In addition, additional strip-shaped anode segments may still be provided. The separator plate 18 is integrally formed in a continuous manner.

In Fig. 3, the electrode unit 10 of Fig. 2 according to the first embodiment is shown in a schematic sectional view. In this case, the anode current conductor 31 is formed integrally in a continuous manner. In this case, at least two strip-like anode segments 71, 72 are arranged parallel to each other on the subsequent anode current conductor 31 and separated from each other.

The cathode 22 is constructed similarly to the anode 21 and comprises a cathode active material 42 comprising a first strip-shaped cathode segment 81 and at least one second strip-shaped cathode segment 82 ). The strip-shaped cathode segments 81 and 82 are arranged parallel to one another on the cathode current conductor 32, which is integrally formed in the following manner. In addition, additional strip-shaped cathode segments may still be provided.

In addition, at least two strip-like anode segments 71, 72 and at least two strip-shaped cathode segments 81, 82 are also located on the following integral separator plate 18.

Further, in one modification of the first embodiment of the electrode unit 10, the anode active material 41 or the cathode active material 42 may be formed integrally in a continuous manner.

Fig. 4 shows a schematic cross-sectional view of the electrode unit 10 of Fig. 2 according to the second embodiment. In this case, the anode current conductor 31 comprises a first strip-shaped anode conductor segment 76 and at least one second anode conductor segment 77, which are separated from one another while extending parallel to one another . In addition, additional strip-shaped anode conductor segments may still be provided.

The first strip-shaped anode segment 71 is disposed on the first strip-shaped anode conductor segment 76. The second strip-type anode segment 72 is disposed on the second strip-type anode conductor segment 77. In addition, additional strip-shaped anode segments may still be placed on additional anode conductor segments.

The cathode 22 is constructed similarly to the anode 21 and includes a cathode active material 42 that includes a first strip cathode segment 81 and a second strip cathode segment 82 do. In addition, additional strip-shaped cathode segments may still be provided. The cathode current conductor 32 includes a first strip-shaped cathode conductor segment 86 and a second cathode conductor segment 87, which are separated from one another while extending parallel to one another. In addition, additional strip-shaped cathode conductor segments may still be provided.

The first strip-shaped cathode segment 81 is disposed on the first strip-shaped cathode conductor segment 86. The second strip-shaped cathode segment 82 is disposed on the second strip-shaped cathode conductor segment 87. In addition, still further strip cathode segments may also be placed on the additional cathode conductive segments.

In addition, the strip-shaped anode segments 71, 72 and the strip-shaped cathode segments 81, 82 are also located on the succeeding integral separator plate 18.

Further, in a modification of the second embodiment of the electrode unit 10, the anode current conductor 31 or the cathode current conductor 32 may be formed integrally in a continuous manner.

Fig. 5 shows a schematic top view of the electrode unit 10 of Fig. 2 according to the third embodiment. The electrode unit 10 according to the third embodiment is similar to the electrode unit 10 shown in Fig. 4 according to the second embodiment.

4, the first anode conductor segment 76 of the anode current conductor 31 and the second anode conductor segment 77 of the anode current conductor 31 are connected to the connecting webs 90, Lt; / RTI > In the same manner, the first cathode conductor segment 86, which is not visible in this view of the cathode current conductor 32, and the second cathode conductor segment 87, which is not visible in this view, And are connected to each other via non-visible connection webs 90.

In a variation of the third embodiment of the electrode unit 10 the connecting webs 90 of the anode current conductor 31 or the connecting webs 90 of the cathode current conductor 32 may be omitted. Further, in another modification of the third embodiment of the electrode unit 10, the anode current conductor 31 or the cathode current conductor 32 may be formed integrally in a continuous manner.

For example, if there is a defect in the first anode segment 71, the balancing current Ia will flow through at least one connecting web of connecting webs 90, for example from the defective first anode segment 71 to the neighboring second And flows toward the anode segment 72. In this case, the balancing current Ia flows in parallel to the winding axis A of the electrode unit 10 realized as the electrode coil in this case. During times when the battery cell 2 is neither charged nor discharged, the balancing currents Ia directly indicate the presence of a cell defect. When discharging or charging the battery cell 2, the normal currents flowing through the anode segments 71 and 72 flow in a direction different from the balancing current Ia, in this case, almost at right angles to the balancing current.

Accordingly, the balancing current Ia produces a magnetic field having a different directionality from the magnetic fields generated by the normal currents flowing through the anode segments 71, 72. [

For example, if there is a defect in the first cathode segment 81, the balancing current Ia may flow through at least one connecting web of connecting webs 90, such as from a defective first cathode segment 81 to a neighboring 2 cathode segment < RTI ID = 0.0 > 82 < / RTI > In this case, the balancing current Ia flows parallel to the winding axis A of the electrode unit 10 realized as the electrode coil. The normal currents flowing through the cathode segments 81 and 82 flow around the winding axis A in the present embodiment. Accordingly, the normal currents flowing through the cathode segments 81 and 82 flow in a direction different from the balancing current Ia, in this case, almost at right angles to the balancing current.

Accordingly, the balancing current Ia produces a magnetic field having a different directionality from the magnetic fields generated by the normal currents flowing through the cathode segments 81 and 82. [

The detection of the balancing current Ia is possible through the detection of the magnetic field generated by the balancing current Ia. In Fig. 6, a battery cell 2 including an integrated sensor 50 for the detection of a magnetic field is shown schematically.

The electrode unit 10 realized as the electrode coil is disposed in the cell housing 3 in such a manner that the winding axis A extends in a direction extending parallel to the connection line between the cathode terminal 11 and the cathode terminal 12. [ .

An anode current conductor (not shown) 31 is connected to the cathode terminal 11 by a collector 52. The cathode current conductor 32, not shown, is connected to the cathode terminal 12 by a collector 52.

The sensor 50 for detecting the magnetic field is mounted in such a manner that it is spaced at substantially the same distance from the terminals 11 and 12 inside the cell housing 3 in this embodiment. In this case, the sensor 50 is oriented in such a manner that the sensor 50 can detect a magnetic field generated by a current flowing in parallel to the winding axis A. In particular, the sensor 50 does not detect a magnetic field generated by a current flowing tangentially to the winding axis A along the circumference of the winding axis A.

In the case of the electrode units 10 shown in Figs. 2, 3, 4 and 5, the strip-type anode segments 71 and 72, the strip-shaped cathode segments 81 and 82, Shaped cathode conductor segments 86, 87 extend tangentially to the winding axis A, respectively. In addition, the strip-shaped anode segments 71, 72, the strip-shaped cathode segments 81, 82, the strip-shaped anode conductor segments 76, 77 and the strip-shaped cathode conductor segments 86, It is also possible to extend parallel to the plane A of FIG.

In such a case, the balancing current Ia caused by the defect may flow in a direction tangential to the winding axis A to produce a corresponding magnetic field. Then, for the detection of the balancing current Ia, a sensor 50 is provided which is oriented in such a way that the sensor 50 can detect the magnetic field generated by the current flowing tangentially to the winding axis A. .

The present invention is not limited to the embodiments described herein and to the aspects emphasized in these embodiments. On the contrary, it is intended to cover various modifications within the scope of the invention as defined by the appended claims.

2: Battery cell
3: Cell housing
10: electrode unit
11: cathode terminal
12: positive terminal
15: electrolyte
18: Split plate
21: anode
22: Cathode
31: anode current conductor
32: cathode current conductor
41: anode active material
42: cathode active material
50: Sensor
52: Collector
71: first strip anode segment
72: second strip-shaped anode segment
76: first strip-type anode conductor segment
77: second strip-type anode conductor segment
81: first strip-shaped cathode segment
82: Second strip-shaped cathode segment
86: first strip-shaped cathode conductor segment
87: second strip-shaped cathode conductor segment
90: connecting web
A: Winding axis
Ia: Balancing current

Claims (10)

An electrode unit (10) for a battery cell (2)
An anode 21 having an anode active material 41 and an anode current conductor 31,
A cathode 22 having a cathode active material 42 and a cathode current conductor 32, and
And a separator plate (18) separating the anode (21) from the cathode (22), the electrode unit comprising:
The anode active material 41 is in the form of strip-shaped anode segments 71 and 72 and / or the cathode active material 42 is in the form of strip-shaped cathode segments 81 and 82 , And the separator plate (18) is formed in a continuous manner. The electrode unit (10) for a battery cell according to claim 1, characterized in that the anode current conductor (31) is formed in a continuous manner and / or the cathode current conductor (32) is formed in a continuous manner. 7. A device according to claim 1, characterized in that the anode current conductor (31) is in the form of strip-like anode conductor segments (76, 77) and / or the cathode current conductor (32) , 87). ≪ / RTI > 7. A method according to claim 3, wherein the anode conductor segments (76,77) are connected to one another via connecting webs (90) and / or the cathode conductor segments (86,87) (10). The electrode unit (10) for a battery cell according to any one of claims 1 to 3, A battery cell (2) comprising at least one electrode unit (10) according to any one of claims 1 to 4. A method for operating a battery cell (2) according to claim 5,
The balancing current Ia flowing from one anode segment 71 or 72 to the neighboring anode segment 71 or 72 is detected and /
Characterized in that a balancing current (Ia) flowing from one cathode segment (81, 82) to a neighboring cathode segment (81, 82) is detected. The method according to claim 6,
Flows through the anode current conductor 31 formed in the following manner, and / or
Characterized in that the magnetic field produced by the balancing current (Ia) flowing through the cathode current conductor (32) formed in the following manner is measured. The method according to claim 6,
Connecting the anode conductor segments 76, 77 to each other, and / or
Characterized in that a magnetic field produced by the balancing current (Ia) flowing through the connecting web (90) connecting the cathode conductor segments (86, 87) to each other is measured. The method according to claim 6,
Connecting the anode conductor segments 76, 77 to each other, and / or
The voltage applied to the connecting web 90 connecting the cathode conductor segments 86, 87 to each other is measured,
Characterized in that the voltage is generated by the balancing current (Ia) flowing through the connecting web (90). Use of the battery cell (2) according to claim 5 in a fixed energy storage device, in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV) or in a consumer electronics product.

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