WO2014037169A1

WO2014037169A1 - Electrical energy storage cell and method for producing an electrical energy storage cell

Info

Publication number: WO2014037169A1
Application number: PCT/EP2013/066186
Authority: WO
Inventors: Martin Kessler; Volker Doege; Andy Tiefenbach; Alexander Schmidt
Original assignee: Robert Bosch Gmbh
Priority date: 2012-09-05
Filing date: 2013-08-01
Publication date: 2014-03-13
Also published as: CN104584275B; CN104584275A; DE102012215748A1

Abstract

The invention relates to an electrical energy storage cell with a plurality of first planar electrode foils having cutouts on a long side thereof, and a plurality of second planar electrode foils having contact lugs on a long side thereof, said contact lugs being congruent with the cutouts. The first planar electrode foils and the second planar electrode foils are stacked alternately and in plane-parallel relative each other to give a storage cell stack such that the contact lugs alternately overlap the cutouts.

Description

Description title

Electric energy storage cell and method for producing an electrical

Energy storage cell

The invention relates to an electrical energy storage cell and a method for

Producing an electrical energy storage cell.

State of the art

Usually, electrical energy storage cells are taken from direct current or direct current fed into them. Therefore, the previously known construction of

Energy storage cells designed to optimize the ohmic internal resistance and the specific energy and power density of the energy storage cells.

In many applications of electrical energy storage cells, memory cells are connected in series or in parallel with each other to battery modules to set desired output parameters such as total voltage, voltage range, energy content or power density. The document DE 10 2010 035 1 14 A1 discloses, for example, a battery unit with a multiplicity of cell units, each of which has accumulator cells which are electrically coupled via busbars. Document EP 2 413 414 A2 discloses a battery cell with stacked anode and cathode foils in a foil housing, which are connected via cathode and anode conductors to pole terminals of the battery cell.

The document WO 201 1/1 16807 A1 discloses a battery cell with a

electrochemically active electrode stack, whose electrode films each with

Contact lugs are connected to Polleiteranschlüssen. The document WO 2009/073492 A2 discloses a battery cell with electrode foils which

Have extension sections, which can be connected to Polanschlüssen. Document JP 2008108477 A discloses a production method for an electrical energy store with a cylindrical electrode foil stack, from which electric contacting lugs protrude in helical staircase-like form. If currents with increasing alternating component are removed from such energy storage cells, the influence of the distributed inductance of the frequency increases depending on frequency

Energy storage cells. The inductive losses of an energy storage cell are composed of the individual components of the loss contributions of the electrodes, the Polverschaltung and the arrangement of the electrodes in the housing. In addition, at

Operating frequencies in the kHz range due to the skin effect Losses in the current-carrying areas and eddy currents in electrically conductive areas, for example in the

Housing, occur. Energy storage cells may typically include one or more cell wraps integrated into their own or common housings. Usual forms of

Energy storage cells are cylindrical cells, pouch cells or flat cells. In this case, the energy storage cells on distributed inductors, which are due to the cell-internal interconnection, the Ableitergeometrie and the Polanschlüsse. If the energy storage cells are used for example in battery systems with integrated converter, so-called BDIs, these inductive components of the

Energy storage cell impedance at high operating frequencies of the inverter lead to correspondingly high energy losses in the power electronic switching devices of the inverter. As a result, this can lead to increased wear of the

Switching devices, a lower efficiency of the BDIs and increased production engineering effort to implement cooling systems with sufficient cooling performance.

There is a need for energy storage cells which have lower losses with regard to the removal of alternating currents of high frequency and thus the

Improve the efficiency of the system using the energy storage cells.

Furthermore, there is a need for such energy storage cells, which can be wired in a simple manner and with low ohmic and inductive impedance to energy storage modules.

Disclosure of the invention

The present invention provides in one aspect an electrical

Energy storage cell, comprising a plurality of first planar electrode films, each having a recess on one longitudinal side, and a plurality of second planar electrode films, each having on a longitudinal side a Kontaktierungsfahne, which is congruent with the recesses, wherein the first planar

Electrode sheets and the second planar electrode films plane-parallel to each other and are stacked alternately to a storage cell stack, so that the

Contact lugs alternately overlap with the recesses.

According to a further aspect, the present invention provides a method for producing an electrical energy storage cell, comprising the steps of alternately arranging a plurality of first planar electrode films, each having a recess on one longitudinal side, and a plurality of second planar electrode films, each at one Longitudinal side a Kontaktierungsfahne, which is congruent with the recesses, have, wherein the first flat

Electrode foils and the second planar electrode foils are stacked plane-parallel to each other alternately to a memory cell stack, so that the

Contact lugs each overlap alternately with the recesses, the electrical contacting of the recesses surrounding

Contacting areas with a first planar contact element, which in an extension plane perpendicular to the plane of extension of the first planar

Electrode foils is arranged, and the electrical contacting of the

Contact lugs with a second planar contact element, which in an extension plane perpendicular to the plane of extension of the first planar

Electrode foils is arranged.

Advantages of the invention

It is an idea of the present invention to reduce the losses caused by eddy currents occurring in the control of an electrical energy storage cell in the interior of the energy storage cell and / or in its housing by means of a suitable internal structure of the energy storage cell with the lowest possible internal cell inductance. In this case, a film geometry for the stacked electrode films of the energy storage cell is used, in which by the

Contacting the electrode films with Zellpolanschlüssen minimal cell inductance results. This is achieved in that the electrode films in perpendicular to the

Have film plane staggered contacting lugs that interlock with each other in a stacking of the electrode films in the film normal direction. A significant advantage is that the energy loss can be significantly reduced, especially in the removal of high frequency alternating current from the energy storage cell. Especially in battery systems with integrated inverter, so-called battery direct inverters ("BDI"), in which a quick change of the power supply through a battery module to vary the

Voltage is applied, this reduction in energy loss is a great advantage. This is possible to a large extent by the reduction of the cell inductance by low-resistance internal electrode interconnection and a reduction of the contact resistances, in particular at the pole connections of the energy storage cell.

Particularly advantageous is the two-dimensional contacting of the individual electrode films and the contact lugs with the Zellpolanschlüssen, resulting in minimized ohmic resistance within the energy storage cell and minimized by the current within the energy storage cell enclosed flooding surfaces. This can reduce the eddy current formation and thus the energy losses in the AC operation of the energy storage cell.

Another advantage is that the short-term dynamics of such

Energy storage cells is improved by the delay of the energy or

Load output of the energy storage cells is minimized after load changes. As a result, it is advantageously possible to dispense with otherwise possibly compensating components such as, for example, buffer capacitors, which can reduce the space requirement and the manufacturing costs of components which insert energy storage cells. In addition, due to the improved dynamics of the energy storage cells, the avalanche energy, which reduces the AC losses in the energy storage cells for feeding a BDI from an energy storage module with such energy storage cells, is reduced

Switching devices of the BDI means. Moreover, by avoiding inductive loss shares through the

Energy storage cells, the electromagnetic compatibility (EMC) can be improved because the emitted electromagnetic fields can be reduced and interference on adjacent electronic components can be reduced. Furthermore, ohmic losses, for example, due to the skin effect, largely reduced, which is advantageously associated with increased efficiency and lower heat generation.

According to one embodiment of the energy storage cell according to the invention, the first and second sheet-like electrode films can form anode foils or cathode foils of the energy storage cell.

According to a further embodiment of the energy storage cell according to the invention, the recesses and the contact lugs can have a rectangular outline exhibit. These outline shapes are simple and inexpensive to manufacture. Furthermore, rectangular outline shapes provide sufficiently wide longitudinal sides

Contacting sections to which surface contacting elements can be attached.

According to a further embodiment of the energy storage cell according to the invention, the recesses and the contacting lugs can each be formed in the middle of the longitudinal sides of the first or second planar electrode foils. According to a further embodiment of the energy storage cell according to the invention, the energy storage cell further comprises a first planar contact element, which is arranged in an extension plane perpendicular to the plane of extension of the first planar electrode foils, and which is electrically contacted with the contact areas surrounding the recesses, a second planar contact element, which in a Extension plane is arranged perpendicular to the plane of extension of the second planar electrode films, and which is electrically contacted with the Kontaktierungsfahnen, and having an insulating layer, which is disposed between the first planar contact element and the second planar contact element, and which the first planar contact element electrically from the second insulated flat contact element. By this type of contacting a low-resistance and low-inductive connection of the memory cell stack can be realized with Zellpolanschlüssen the energy storage cell.

According to one embodiment of the method according to the invention, the method may further comprise the step of forming an insulating layer between the first planar contact element and the second planar contact element, which electrically isolates the first planar contact element from the second planar contact element. Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

Brief description of the drawings In the drawings:

Fig. 1 is a schematic representation of an electrode foil of an electrical

Energy storage cell according to an embodiment of the invention; FIG. 2 shows a schematic illustration of a further electrode foil of an electrical energy storage cell according to a further embodiment of the invention; FIG.

3 shows a schematic representation of an electrical energy storage cell according to a further embodiment of the invention;

4 shows a schematic illustration of an electrical energy storage cell according to a further embodiment of the invention; and

5 shows a schematic representation of a method for producing an electrical energy storage cell according to a further embodiment of the invention.

The directional terminology used herein, that is, terms such as "left," "right," "top," "bottom," "front," "rear," "above," "behind," and the like, will be understood only for convenience of the drawings, and shall in no case constitute a restriction on the general public. Like reference numerals generally designate like or equivalent components. The illustrations shown in the figures are partly perspective representations of elements which, for reasons of clarity, are not necessarily depicted true to scale. It is understood that in the figures schematic diagrams of components and

Elements whose specific dimensions are considered in the context of a

Vary professional and can be adapted to the particular application.

Electric energy storage cells in the sense of the present invention include all devices which store electrical energy over a predefined period of time and can deliver it again over a further period of time. Energy storage cells in the context of the present invention encompass all types of secondary and primary energy stores, in particular electrically capacitive, electrochemical

(faradaysche) and combined storage types. The periods considered can range from seconds to hours, days or years.

Electrical energy storage cells can be, for example, lithium-ion cells, lithium-polymer cells, nickel-metal hydride cells, ultracapacitors, supercapacitors, power capacitors, BatCaps, batteries based on lead, zinc, sodium, lithium, magnesium, sulfur or other metals, Elements or alloys, or include similar systems. The functionality of the encompassed by the invention electric energy storage cells can be used on intercalation electrodes,

Reaction electrodes or alloy electrodes in combination with aqueous, aprotic or polymeric electrolytes are based. The construction of electrical energy storage cells in the sense of the present invention can be both different outer structures, such as

prismatic shapes or so-called "pouch" shapes, as well as different electrode structures, such as wound, stacked, folded or other constructions include.

Electrode foils in the sense of the present invention can be produced from various electrically conductive, for example metallic, materials such as copper, aluminum, nickel, chromium, silver, gold, platinum, zinc, tin or alloys of these metals. Electrode foils, in particular anode foils and / or cathode foils in the sense of the present invention, can be coated and / or produced with a large active surface area. In this case, the electrode films can be designed to lie flat and plane-parallel to one another. The electrode films can be different

Have dimensions, for example, the thickness of electrode elements may have orders of magnitude of a few μηη to several mm. The electrode elements may be folded, stacked or wound, and it may be provided to form insulation or separation layers between the electrode films which galvanically separate the electrode films from one another and can separate the electrolyte into individual regions within the cell housing. It may also be possible to build up the electrode foils in bipolar form. The planar shape of the electrode films can be square, rectangular, round, elliptical or any other design.

Electric energy storage modules according to the present invention comprise components which have one or more electrical energy storage cells in a housing, wherein the electrical energy storage cells are suitably electrically coupled to one another in order to ensure a serial or parallel connection of the energy storage cells. Electrical energy storage modules can have module connections to which an output voltage dependent on the internal connection of the electrical energy storage cells of the electrical energy storage module can be tapped off.

Housing in the context of the present invention include all components which have a recess for receiving one or more electrical energy storage cells and the electrically conductive interconnection elements of the electrical energy storage cells and which can mechanically and / or electrically shield the recorded energy storage cells and elements from the outside world. Housings may comprise electrically conductive materials, electrically non-conductive materials or only poorly conductive materials or combinations of partial areas of such materials, such as, for example, plastics, metals, alloys of metals. The shape and size of the housing can be adapted to the recorded energy storage cells and elements.

1 shows a schematic representation of a sheet-like electrode film 1 which can be used for the production of an electrical energy storage cell 10. The electrode film 1 can be used, for example, as an anode or cathode film for forming a memory cell stack of an energy storage cell 10. The

Electrode foil 1 has a main section or stack section 2, in which the electrochemically active region of the energy storage cell 10 is formed. In the example of FIG. 1, the electrode film 1 is rectangular in outline. The electrode film 1 also has on a lower longitudinal side a recess 2e, of two

Contacting sections 2c and 2d is surrounded. The recess 2e can

preferably be arranged in the middle of the longitudinal side of the electrode film 1. The recess 2e has a rectangular outline. However, it is clear that other contours for the recess 2e are also possible. The depth of the recess 2 e may preferably occupy a fraction of the depth of the entire depth extension of the electrode film 1. The length of the recess 2e may correspond, for example, the width of the contacting sections 2c and 2d, that is, the

Recess has a length which is about one third of the total length of the electrode film 1. However, it is clear that other dimensions of the length of the recess 2e are also possible.

FIG. 2 shows a schematic representation of a further planar electrode film 3 which can be used for the production of an electrical energy storage cell 10. The electrode foil 3 may be used as the anode foil or cathode foil for forming a storage cell stack as the electrode foil 1 in FIG

Energy storage cell 10 can be used. The electrode foil 3 has a

Main section or stacking section 4, in which the electrochemically active region of the energy storage cell 10 is formed. In the example of FIG. 2 is the

Electrode foil 3 rectangular in outline. The electrode foil 3 also has on a lower longitudinal side a contacting lug 4c whose outline is congruent to the outline of the recesses 2e of the electrode foils 1. It can the

Kontaktierungsfahne 4c preferably in the middle of the longitudinal side of the electrode film. 3 be arranged. The Kontaktierungsfahne 4c has a rectangular outline. However, it will be understood that other contours for the contacting tab 4c are also possible, and that the contour shape will depend on the shape of the recesses 2e. The depth of the Kontaktierungsfahne 4c may preferably occupy a fraction of the depth of the entire depth extent of the electrode film 3. The length of the

Kontaktierungsfahne 4c may correspond, for example, the width shortened end portions 4a, 4b of the electrode film 3, that is, the Kontaktierungsfahne has a length which is about one third of the total length of the electrode film 3. However, it is clear that other dimensions of the length of Kontaktierungsfahne 4c are also possible.

FIG. 3 shows a schematic representation of a storage cell stack comprising a plurality of first planar electrode films 1 and a plurality of second planar ones

Electrode foils 3. Here are the first two-dimensional electrode foils anode foils 1 and the second flat electrode foils without limiting the generality

Cathode foils 3.

The anode foils 1 and cathode foils 3 are each plane-parallel to each other and stacked in an alternating sequence, so that the recesses 2 e and the

Contact lugs 4c having longitudinal sides of the electrode films 1 and 3 each come to lie one above the other and form a memory cell stack. The

Anode foils 1 and cathode foils 3 may, for example, have a rectangular, square, parallelogram-shaped, trapezoidal or strip-like shape. The number of anode foils 1 and cathode foils 3 is shown in Fig. 3, each with three, but their number is not limited in principle. Advantageously, the number of

Anodenfolien 1 and cathode foils 3 may be the same, so that each pair of anode foils 1 and cathode foils 3 can be formed in the memory cell stack. The pairs of anode foils 1 and cathode foils 3 can each be separated by a layer of a separator layer or insulation layer (not explicitly shown), which are arranged plane-parallel in the memory cell stack between one of the anode foils 1 and one of the cathode foils 3. The anode foils 1 and cathode foils 3 can be galvanically separated from one another within the energy storage cell 10 by the separator layers. In particular, the separator layers serve to separate the electrolyte into segments so that a specific electrical potential difference within this segment in the electrolyte is not exceeded. They can do this

For example, thin layers of electrically or only slightly conductive materials exhibit. It should be clear that there are plenty of opportunities that

To arrange anode foils 1, cathode foils 3 and separator layers in a memory cell stack, and that the selection of an arrangement of the used

Memory technology, the constraints on the external shape of the

Energy storage cell 10 and / or to be achieved electrical characteristics of the energy storage cell 10 may be dependent. For example, it may be advantageous to design the storage cell stack such that the internal volume of the

Energy storage cell 10 is utilized to the maximum. 4 shows a schematic representation of an electrical energy storage cell 10, whose first planar electrode films 1 are electrically connected to a first planar contact element 5. The first planar contact element 5 can in a

Extension plane perpendicular to the plane of extension of the first planar

Electrode sheets 1 may be arranged. In this case, the first planar contact element 5 is electrically contacted with the contacting regions 2c, 2d which surround the recesses 2e on the longitudinal side of the electrode films 1. Similarly, the second planar electrode films 3 are electrically connected to a second planar contact element 6, which is arranged in an extension plane perpendicular to the plane of extent of the second planar electrode films 3. The second planar contact element 6 contacts the Kontaktierungsfahnen 4c electrically.

Between the first planar contact element 5 and the second planar

Contact element 6 may be provided an insulating layer 7, which electrically isolates the first planar contact element 5 from the second planar contact element 6. As symbolized schematically by the ring currents I in FIG. 4, eddy currents flow very closely through the respective electrode films 1 and 3, that is, the flow areas enclosed by the ring currents I are very small. As a result, the input inductance of the energy storage cell 10 is also very low. Due to the central arrangement of the recesses 2e and the Kontaktierungsfahnen 4c two parallel ring current paths I are also constructed, the parallel circuit, the resulting

Total inductance of the energy storage cell can further reduce.

The first and second planar contact elements 5 and 6 can each be electrically connected to not explicitly shown first and second Zellpolanschlüssen the energy storage cell 10. In this case, the cell pole connections can be led out of a (not explicitly shown) cell housing of the energy storage cell 10 in order to minimize the distance between the storage cell stack and the cell housing. The cell pole connections are implemented in such a way that at least one of the Zellpolanschlüsse is electrically insulated from the cell housing. In this case, for example, a metallic cell housing or a cell housing made of an insulating material such as plastic may be used. The energy storage cell 10 may for example be enclosed by a prismatic cell housing. However, it will be understood that any other shape for the cell housing is also possible, and that this shape may be, for example, the dimensions of the enclosed ones

Energy storage cell 10 may be dependent.

Electrical energy storage modules can be an array of electrical

Energy storage cells 10 which are coupled together along their Zellpolanschlüsse in series or parallel connection. It should, however, be clear that any other arrangement of different energy storage cells 10 is also possible by adapting the respective interconnected energy storage cells 10 for an electrical energy storage module. In particular, parallel and / or series connection or combined parallel and series connection of energy storage cells 10 can be realized. The electrical energy storage module, for example, have a module housing, from which at the end cell pole connections in each case

Modulpolanschlüsse are led out of the module housing. The

Module pole connections can be, for example, flat contact elements, of which at least one is electrically insulated from the module housing.

Overall, Figs. 1 to 4 show only exemplary embodiments of energy storage cells 10. Variations and modifications may be under

Be taken into account by purposeful design criteria.

In general, it is advantageous, the distances between current-carrying elements of both

Keep polarities as low as possible in order to minimize the active flooding area enclosed by these elements. This means that the inductive impedance of the current-carrying elements inside the energy storage cells 10 can be minimized. Moreover, it is advantageous to design the current-carrying elements as large as possible in order to distribute the current density as homogeneously as possible. Is an ideal area, closely fitting to the active areas of the contact elements Polkontaktierung only under certain conditions possible, such as

Safety requirements or technical constraints, so it is at least to make sure to ensure the merger of the current-carrying elements of different polarity at a small distance from each other. Furthermore, it is advantageous to minimize the number of necessary pole connections of the energy storage cells 10 to the housing by means of suitable module-internal connection of the energy storage cells. As a result, the ohmic line resistances are reduced, which in turn results in both DC operation as well as in AC operation in a minimization of ohmic losses, in particular due to the skin effect, results.

For example, the illustrated energy storage cells 10 may be preferably used in systems where high frequency alternating currents are out of the

Energy storage cells 10 are removed, for example, in Batteriedirektumrichtern with drive frequencies above about 100 Hz. In these systems 10 due to the design of the energy storage cells inductive losses due to the high AC frequency can be minimized. At the same time, that improves

Responses of the energy storage cells 10 in the short-term range, which significantly improves the dynamics and reliability of the systems.

5 shows a schematic representation of a method 30 for producing an electrical energy storage cell 10, in particular an energy storage cell 10 shown schematically in connection with FIGS. 1 to 4. In a first step 31, an alternating arrangement of a multiplicity of first planar electrode films 1 takes place. which each have a recess 2e on one longitudinal side, and a multiplicity of second planar electrode films 3, which each have a longitudinal side

Contact lug 4c, which is congruent with the recesses 2e have. In this case, the planar electrode films 1 and 3 are stacked plane-parallel to each other and alternately to a memory cell stack, so that the Kontaktierungsfahnen 4c each overlap alternately with the recesses 2e.

In a second step 32, an electrical contacting of the recesses 2e surrounding contacting regions 2c and 2d takes place with a first planar

Contact element 5, which in an extension plane perpendicular to the

Extension plane of the first planar electrode films 1 is arranged. Then, in a third step 33, an electrical contacting of the contacting lugs 4 c with a second planar contact element 6, which is arranged in an extension plane perpendicular to the plane of extension of the first planar electrode films 1.

Optionally, furthermore, the step 34 of forming an insulation layer 7 between the first planar contact element 5 and the second planar contact element 6 can take place, the insulation layer 7 electrically insulating the first planar contact element 5 from the second planar contact element 6.

Claims

Claims 1. Electric energy storage cell (10), with:

a plurality of first planar electrode foils (1) which each have a recess (2e) on one longitudinal side; and

a plurality of second sheet-like electrode foils (3) each having on a longitudinal side a contacting lug (4c) which is congruent with the recesses (2e),

wherein the first two-dimensional electrode films (1) and the second planar

Electrode sheets (3) plane parallel to each other and alternately to a

Memory cell stack are stacked, so that the Kontaktierungsfahnen (4c) each overlap alternately with the recesses (2e).

2. Electrical energy storage cell (10) according to claim 1, wherein the first and second sheet-like electrode films (1; 3) anode foils or cathode foils of

Form energy storage cell (10).

3. Electrical energy storage cell (10) according to any one of claims 1 and 2, wherein the recesses (2e) and the Kontaktierungsfahnen (4c) have a rectangular outline.

4. Electrical energy storage cell (10) according to one of claims 1 to 3, wherein the recesses (2 e) and the contacting lugs (4 c) respectively in the middle of

Longitudinal sides of the first and second sheet-like electrode films (1, 3) are formed.

5. Electrical energy storage cell (10) according to one of claims 1 to 4, further comprising: a first planar contact element (5) which is arranged in an extension plane perpendicular to the plane of extension of the first planar electrode films (1), and which with the recesses ( 2e) surrounding

Contacting regions (2c, 2d) is electrically contacted;

a second planar contact element (6), which is arranged in an extension plane perpendicular to the plane of extent of the second planar electrode films (3), and which is in electrical contact with the contact lugs (4c); and

an insulating layer (7) which is arranged between the first planar contact element (5) and the second planar contact element (6), and which is the first flat contact element (5) electrically isolated from the second flat contact element (6).

6. Method (30) for producing an electrical energy storage cell (10), comprising the steps:

alternating arrangement (31) of a multiplicity of first planar electrode foils (1) which each have a recess (2e) on one longitudinal side and a multiplicity of second planar electrode foils (3) which each have on one longitudinal side a contact lug (4c) is congruent with the recesses (2e), in which the first planar electrode films (1) and the second planar electrode films (3) are stacked plane-parallel to each other alternately to a memory cell stack, so that the contacting lugs (4c) each alternately with the recesses (2e ) overlap;

electrically contacting (32) surrounding the recesses (2e)

Contacting regions (2c, 2d) having a first planar contact element (5) which is arranged in an extension plane perpendicular to the plane of extent of the first planar electrode films (1); and

electrically contacting (33) the contacting lugs (4c) with a second planar contact element (6), which is arranged in an extension plane perpendicular to the plane of extent of the first planar electrode foils (1).

The method (30) of claim 6, further comprising the step:

Forming (34) an insulating layer (7) between the first planar

Contact element (5) and the second planar contact element (6) which electrically isolates the first planar contact element (5) from the second planar contact element (6).