Energy storage cell with a separator featuring reduced transverse in-plane electrolyte pore flow resistance

Abstract

The invention relates to an energy storage cell, configured as a lithium-ion storage cell or sodium-ion storage cell, comprising an anode, a cathode, a separator located between the anode and the cathode, and an electrolyte solution arranged in pores of the anode, cathode, and separator, wherein the ratio of R p,Separator,t-IP / R p,Anode,t-IP has a value of 0.33 or less, preferably a value of 0.1 or less, wherein R p,Separator,t-IP the transverse in-plane pore flow resistance for the electrolyte solution in the separator is and corresponds to the quotient of the porosity of the separator and the transverse in-plane permeability for the electrolyte solution in the separator, and R p,Anode,t-IPThe transverse in-plane pore flow resistance for the electrolyte solution in the anode corresponds to the quotient of the anode porosity and the transverse in-plane permeability of the electrolyte solution in the anode. Such a power storage cell exhibits reduced aging compared to conventional power storage cells.

Description

[0001] The present invention relates to an energy storage cell with a separator having a reduced transverse in-plane electrolyte pore flow resistance compared to an anode. The present invention further relates to a use of the energy storage cell and a method for selectively reducing the transverse in-plane pore flow resistance of the electrolyte solution in a separator compared to the transverse in-plane pore flow resistance of the electrolyte solution in the anode.

[0002] In a lithium-ion or sodium-ion energy storage cell, ion transport between the anode and cathode is facilitated by an electrolyte solution containing a lithium or sodium conducting salt and at least one solvent. This electrolyte solution is present in the pores of the anode and cathode, as well as in the pores of the separator located between the anode and cathode. When filling an energy storage cell with an electrolyte solution, the solution is typically added in excess volume relative to the available pore volume in the cell to achieve a high-capacity, long-life energy storage cell.A known mechanism for the aging of energy storage cells is the deposition of lithium on the anode, known as "lithium plating" in lithium-ion cells, or the deposition of sodium on the anode, known as "sodium plating" in sodium-ion cells. This metal deposition on the anode leads to a rapid loss of the energy storage cell's capacity. To prevent metal deposition on the anode, it is desirable, especially during the charging process, to ensure that the anode potential is not less than or equal to 0 volts relative to a Li / Li cell. + or Na / Na + Reference electrode is used.

[0003] The object of the present invention is to provide an energy storage cell, configured as a lithium-ion or sodium-ion storage cell, which is improved with respect to the aforementioned disadvantages. A further object of the present invention is to specify an application of the energy storage cell according to the invention for a fast-charging method. The present invention also relates to a method for the targeted reduction of the transverse in-plane pore flow resistance for the electrolyte solution in a separator compared to the transverse in-plane pore flow resistance for the electrolyte solution in the anode and in the cathode.

[0004] One aspect of the present invention provides an energy storage cell, configured as a lithium-ion storage cell or as a sodium-ion storage cell. The energy storage cell comprises an anode, a cathode, a separator located between the anode and the cathode, and an electrolyte solution present in the pores of the anode, cathode, and separator. The separator has a transverse in-plane pore flow resistance ratio for the electrolyte solution in the separator R. p,Separator,t-IP transverse in-plane pore flow resistance for the electrolyte solution in the anode R p,Anode,t-IP of 0.33 or less, preferably 0.1 or less.

[0005] In one embodiment, the separator has a ratio of transverse in-plane pore flow resistance for the electrolyte solution in the separator R p,Separator,t-IP transverse in-plane pore flow resistance for the electrolyte solution in the cathode R p,Kathode,t-IP0.033 or less, preferably 0.01 or less.

[0006] The transverse in-plane pore flow resistance for the electrolyte solution in the separator R p,Separator,t-IP This corresponds to the quotient of the separator porosity and the transverse in-plane permeability for the electrolyte solution in the separator. Similarly, the transverse in-plane pore flow resistance for the electrolyte solution in the anode corresponds to R. p,Anode,t-IP the quotient of anode porosity and transverse in-plane permeability for the electrolyte solution in the anode and the transverse in-plane pore flow resistance for the electrolyte solution in the cathode R p,Kathode,t-IP the quotient of cathode porosity and transverse in-plane permeability for the electrolyte solution in the cathode.

[0007] The porosity n of separator, anode and cathode can each be determined from the ratio of bulk volume V bulk (English: bulk volume) to skeletal volume V skelcalculated according to the following formula: n=1−VskelVbulk

[0008] The bulk volume can be determined based on the layer thickness and the electrode area. The layer thickness can be determined by measuring it with a thickness gauge. The skeletal volume of the separator, anode, and cathode can be determined, for example, using helium pycnometry. To determine the skeletal volume, three independent measurements can be taken for each, and the average value calculated. To determine the bulk volume, three independent areas of the electrode, each with an area of, for example, 2 cm x 2 cm, can be selected. Thickness measurements are then taken at ten different points within each area, and the average value is calculated.

[0009] The porosity of the separator, anode, and cathode each refers to a formed storage cell, preferably at the time of delivery ("Beginning of Life" (BoL)), where the storage cell has already been charged and discharged once after its manufacture, resulting in the formation of boundary layers, particularly on the anode and to a lesser extent on the cathode. On the anode, this boundary layer is referred to as SEI ("solid electrolyte interphase"), and on the cathode as CEI ("cathode electrolyte interphase"). During formation, the electrodes also undergo irreversible volume expansion, particularly through the formation of the SEI or CEI and through a partial rearrangement of the particles, especially in highly compressed electrodes. The porosity is determined at a state of charge (SOC) of 50% of the storage cell.

[0010] The transverse in-plane permeabilities of the anode and cathode can be determined, for example, using flow simulation: Three-dimensional micro-computed tomography (CT) scans of the anode and cathode test volumes are performed. The particle geometries detected in this way are subtracted from the test volume (the volume measured by the CT scan), thus obtaining a geometry of the pore network. In a flow simulation, different flow velocities are applied, and the pressure increase across the test volume is calculated. The transverse in-plane permeability of a separator can also be determined, for example, using flow simulation: This involves, for instance, a digital 3D reconstruction of commonly used materials based on FIB-SEM (focused ion beam scanning electron microscopic) tomography, as described by Lagadec et al., 2018 J. Electrochem. Soc. 165 A1829.For this purpose, separator materials are first prepared by filling the pore volume. Using microstructure simulations, the pressure-dependent porosity and the pressure-dependent permeability in different spatial directions can be determined.

[0011] The relationship between flow rate and pressure increase per unit length is described by Darcy's law: q=QA≈−kμΔpL

[0012] Here, q is the flow rate determined from the volume flow rate Q per cross-sectional area A, µ is the dynamic viscosity of the fluid, and k is the permeability.

[0013] The average pore flow velocity v can now also be calculated using the permeability k and porosity n. p determine the fluid: q=nvp vp≈−knμΔpL

[0014] Expressed in the form of a pore flow resistance R p : vp≈−1Rpμ0ΔpL

[0015] With µ 0 = 1 Pa s. The pore flow resistance R p For a given fluid, the following results: Rp=nk

[0016] It contains ke=k⋅μ0μ the permeability for a given fluid with the unit [m²] 2 ].

[0017] The electrochemically active materials in the anode and the electrochemically active materials in the cathode do not expand uniformly during the charging process. Rather, the electrochemically active materials in the anode often expand significantly more than the electrochemically active materials in the cathode contract.

[0018] During charging, the expansion of the electrochemically active materials in the anode and the contraction of the electrochemically active materials in the cathode change the porosity of each electrode. When the electrochemically active materials of the anode and cathode expand collectively during the charging process, electrolyte is displaced from an electrode coil (jelly roll) or an electrode stack. This occurs through electrolyte flow in the plane of the electrodes (in-plane (IP)).

[0019] The electrochemically active materials of the anode often have a rather flat, plate-like particle shape, while the electrochemically active materials of the cathode typically have a more round, spherical particle shape. To achieve the high energy density required for the electrodes, the electrochemically active materials are usually densified by calendering during electrode production. As in Fig. As outlined in Figure 12a, this compaction at anode 2 leads to an in-plane alignment of the platelet-shaped electrochemically active materials due to the particle shape, and consequently to a comparatively low transverse in-plane pore flow resistance for the electrolyte solution in the anode (R p,Anode,t-IPIn contrast, the compaction at cathode 3, due to the round particle shape of the electrochemically active materials in the cathode, leads to an elongation of the in-plane path length and consequently to a comparatively high transverse in-plane pore flow resistance for the electrolyte solution in the cathode (R). p,Kathode,t-IP The inventors have determined, using the flow simulation described herein, that R p,Anode,t-IP for example, values ​​on the order of about 5·10 10 m -2 can exhibit, whereas for R p,Kathode,t-IP for example, values ​​on the order of about 6·10 11 m -2 This allows an anode to exhibit a pore flow resistance for the electrolyte solution that is approximately one order of magnitude lower compared to a cathode.

[0020] The transverse in-plane permeability k t-IPAccording to Lagadec, typical separator materials based on polyethylene or polypropylene without compressive stress usually exhibit values ​​in the order of k. t-IP ≤ 10 -16 m 2 on.

[0021] After ke=k μ0μ This results from using the dynamic viscosity of the electrolyte: ke,t,Separator−IP≤3⋅10−14m2

[0022] The porosities of typical separator materials are usually in the range of 35% to 50%. This results in a transverse in-plane pore flow resistance of the separator R. p, Separator-t-IP a value on the order of: Rp,separator,t−IP≥1⋅1013m−2

[0023] This allows a separator to have a pore flow resistance for the electrolyte solution that is about one order of magnitude lower compared to a cathode and about two orders of magnitude lower compared to an anode.

[0024] This results in the electrolyte flow primarily taking place in the anode, and during the charging process, the electrolyte solution located in the pores of the anode is preferentially displaced.

[0025] During the charging process, cations of a conducting salt, i.e., lithium ions or sodium ions, are incorporated into the electrochemically active materials of the anode. This incorporation of ions results in the electrolyte solution present in the anode's pores having a lower conducting salt concentration than the initially used concentration. As the inventors have discovered, this also leads to the electrolyte solution displaced from the anode's pores having a lower conducting salt concentration than the initially used concentration. Consequently, different concentrations of the conducting salt can develop in the electrolyte solution in different areas of an electrode during extended operation of the battery cell after several charge and discharge cycles.These different concentrations of conducting salt in the electrodes can lead to premature aging of the storage cell and, in particular, to the deposition of lithium in the case of a lithium-ion storage cell and to the deposition of sodium on the anodes in the case of a sodium-ion storage cell.

[0026] These varying concentrations of conducting salt can develop particularly when electrolyte solution is added in excess compared to the available pore volume of the electrodes and separator, as is normally the case. With an excess of electrolyte solution, particularly large quantities of electrolyte solution with reduced conducting salt concentrations compared to the original concentrations can be displaced from the anode during charging of the storage cell, as the inventors have observed.

[0027] To reduce or prevent this, an R is therefore used according to the invention.p,Separator,t-IP chosen that is smaller than the R p,Anode,t-IP The ratio of R p,Seprataor,t-IP / R p,Anode,t-IP It is set so that it has a value of 0.33 or less, preferably a value of 0.1 or less.

[0028] In one embodiment, the ratio of R p,Seprataor,t-IP / R p,Kathode,t-IP such that it has a value of 0.33 or less, preferably a value of 0.1 or less, more preferably a value of 0.033 or less, in particular a value of 0.01 or less.

[0029] The smaller the ratio of R p,Seprataor,t-IP / R p,Anode,t-IPThe larger the voltage, the more the electrolyte flow resulting from the expansion of the electrochemically active materials of the anode and cathode during charging is shifted from the anode to the separator. Since the separator is located between the anode and the cathode, a proportionally larger amount of electrolyte solution is also displaced from the cathode. By reducing the ratio of R p,Seprataor,t-IP / R p,Anode,t-IP It can be achieved that during the charging process of the storage cell, a similar amount of electrolyte solution with reduced conducting salt concentrations is displaced from the anode as electrolyte solution with increased conducting salt concentrations is displaced from the cathode. This reduces or prevents the formation of different conducting salt concentrations in different areas of the electrode.

[0030] The energy storage cell can comprise an electrode winding or an electrode stack. The electrode winding or the electrode stack can be housed in a casing, the electrode winding and the electrode stack comprising the anode, cathode, and separator described above. The electrode winding or the electrode stack can extend within the casing along a longitudinal axis of the energy storage cell. In the case of an electrode winding, a ribbon anode, a ribbon cathode, and a first ribbon separator located between the ribbon anode and the ribbon cathode, together with a second ribbon separator, can be wound in layers around a core. In the case of an electrode stack, individual anodes, cathodes, and separators located between them can be stacked on top of each other as plate-shaped elements.

[0031] Such energy storage cells can achieve particularly high capacities.

[0032] Preferably, the electrode winding or electrode stack has a length of at least 3 cm along the longitudinal axis of the energy storage cell. Energy storage cells with such lengths along their longitudinal axis exhibit particularly high capacities due to their size. Due to the ratio of R set according to the invention... p,Seprataor,t-IP / R p,Anode,t-IPDifferent areas with varying concentrations of conducting salt along the longitudinal axis of the energy storage cell form only to a minor extent or not at all. Due to the large extent of at least 3 cm along the main axis of the energy storage cell, different concentrations of conducting salt along this main axis cannot normally be equalized by diffusion within a very short time during operation of the energy storage cell and therefore lead to premature aging of the energy storage cell.

[0033] Energy storage cells with a longitudinal dimension of at least 3 cm include, for example, cylindrical cells of type 18650 with a longitudinal dimension of 6.5 cm. Further examples of energy storage cells with such dimensions are cylindrical cells of type 4680 with a longitudinal dimension of 8 cm, cylindrical cells of type 4695 with a longitudinal dimension of 9.5 cm, and cylindrical cells of type 46120 with a longitudinal dimension of 12 cm. Such energy storage cells can be used, in particular, in battery electric vehicles.

[0034] The housing of the energy storage cell can be arranged around the circumference of the electrode winding or electrode stack along its longitudinal axis. The housing can make contact with the main surfaces of the anode and cathode. Alternatively, the housing can completely enclose the electrode stack or electrode winding. Finally, the housing can completely enclose the electrode stack or electrode winding. In particular, a separator layer can be provided between the housing and the respective electrodes for electrical insulation. Such a housing, in which the electrodes or separators of the electrode winding or electrode stack are in contact with the housing, allows for a particularly compact design of the energy storage cells.

[0035] The housing can, in particular, comprise a metallic outer shell or an outer shell made of plastic. The housing can, in particular, be cylindrical, with poles for electrical contacting the energy storage cell located at opposite ends of the cylinder. The housing can also comprise a flexible foil, for example made of aluminum, in which the electrode stack is firmly clamped. Such housings are used, for example, in pouch cells.

[0036] Since the electrode stack or electrode winding is clamped within the housing, there is no space for electrodes perpendicular to the longitudinal axis of the energy storage cells to expand during charging. Therefore, in such energy storage cells, conventional charging with an excess of electrolyte solution particularly easily leads to displacement of the electrolyte solution from the electrode stack or electrode winding, resulting in the formation of areas with differing electrolyte concentrations during operation. This problem can be avoided due to the ratio of R set according to the invention. p,Separator,t-IP / R p,Anode,t-IP reduced or prevented.

[0037] In the energy storage cell, the anode, separator, and cathode can have a first and a second boundary region extending along the longitudinal axis, and a central region extending between the first and second boundary regions along the longitudinal axis. The first boundary region, the second boundary region, and the central region between them can each have the same extent along the longitudinal axis. Furthermore, the first boundary region, the second boundary region, and the central region between them each have an area of ​​equal size. The inventors have observed that in conventional energy storage cells, after several charge and discharge cycles, the electrolyte solution exhibits different concentrations of conducting salt in the pores of the first boundary region, in the pores of the second boundary region, and in the pores of the central region, for example, the anode.This can be achieved by adjusting the ratio of R according to the invention. p,Separator,t-IP / R p,Anode,t-IP reduced or prevented.

[0038] In one embodiment of the energy storage cell according to the invention, the energy storage cell exhibits, after at least 50 charging and discharging cycles (C-rate during charging and discharging at least C / 2, SOC range 0-100% each, temperature 25 °C), after a discharge to the cut-off voltage and resting for approximately 24 hours, a mean concentration of Li in both the first and second edge regions. + or rather, well + in the electrolyte solution, which changes by at most 30%, preferably at most 20%, more preferably at most 10% with respect to the original concentration of Li + or rather, well +in the electrolyte solution, i.e., at the time of delivery (BOL). The average C-rate can be determined, in particular, by the average C-rates occurring during charging over a period of 1 hour. Preferably, the energy storage cell can be charged with the aforementioned concentrations of Li + or rather, well + exhibit at least 130 loading and unloading cycles.

[0039] In a further embodiment of the energy storage cell according to the invention, the energy storage cell exhibits, after at least 50 charging and discharging cycles (C-rate during charging and discharging at least C / 2, SOC range 0-100% each, temperature 25 °C), after a discharge to the cut-off voltage and resting for about 24 hours, a mean concentration of Li in both the first and second edge regions. + or rather, well +in the electrolyte solution, which changes by at most 50%, preferably by at most 40%, more preferably by at most 20% with respect to the concentration of Li + or rather, well + in the electrolyte solution in the middle range. Preferably, the energy storage cell can have the above-mentioned concentrations of Li. + or rather, well + exhibit at least 130 loading and unloading cycles.

[0040] The anode can, in particular, comprise an electrochemically active anode material. An electrochemically active anode material is understood to be, in particular, a material capable of absorbing and releasing lithium ions if the energy storage device is a lithium-ion energy storage device, or sodium ions if the energy storage device is a sodium-ion energy storage device. The electrochemically active material of the anode of the energy storage cell can expand, in particular, during the charging process, depending on the state of charge. This can be attributed, in particular, to the fact that during the charging process, the volume of the electrochemically active anode material increases due to intercalation or alloying of lithium or sodium into the electrochemically active anode material, for example, graphite or silicon oxides, silicon, or mixtures thereof.In one embodiment, the volume of the electrochemically active anode material increases by 5% or more, by 10% or more, by 20% or more, by 40% or more, or by 100% or more during a charging process from 0% SOC to 50% SOC.

[0041] In particular, the electrochemically active anode material can be selected from the group consisting of: synthetic graphite, natural graphite, graphene, mesocarbon, doped carbon, hard carbon, soft carbon, fullerene, silicon-carbon composites, silicon, surface-coated silicon, silicon suboxide, silicon alloys, aluminum alloys, indium, tin alloys, cobalt alloys, and mixtures thereof. Preferably, the electrochemically active anode material can be selected from the group consisting of: graphite, silicon oxides, and silicon, or mixtures thereof. Such electrochemically active anode materials are particularly suitable for providing lithium-ion storage cells with high capacity.

[0042] In a sodium-ion battery, the anode can comprise an electrochemically active anode material. This electrochemically active anode material can be designed to absorb and release sodium ions during charging and discharging. Specifically, the electrochemically active anode material in a sodium-ion battery can be hard carbon, for example, in the form of graphite, which, similar to a lithium-ion battery, can absorb and release sodium ions through intercalation. This process can also lead to an expansion of the electrochemically active anode material in the sodium-ion battery, similar to a lithium-ion battery.

[0043] The cathode can, in particular, comprise an electrochemically active cathode material. In a lithium-ion energy storage cell, an electrochemically active cathode material is understood to be a cathode material capable of releasing and absorbing lithium ions during charging and discharging. In a lithium-ion energy storage cell, the electrochemically active cathode material can be selected from a group consisting of: lithium transition metal oxides such as lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese compounds (known by the abbreviations NCM and NMC, respectively), for example, LiCoO2, LiNi. 0,33 Co 0,33 Mn 0,33O2, lithium nickel cobalt aluminum oxides (NCA), lithium olivines such as lithium iron phosphate (LFP), lithium spinels such as lithium manganese oxide spinel (LMO), lithium manganese nickel spinel (LNMO) or combinations thereof, further preferably wherein the electrochemically active cathode material is selected from a group consisting of: lithium nickel cobalt manganese compounds.

[0044] Suitable cathode materials include, for example, materials containing sodium ions such as phosphates and diphosphates, such as sodium iron phosphates or compounds such as Na 2 / 3 Fe 1 / 2 Mn 1 / 2 O2 is used in a sodium-ion energy storage cell.

[0045] In addition to the electrochemically active anode and cathode materials, the materials for the anode and cathode can contain other materials, such as binders and conductive additives. Examples of binders that can be used include carboxymethylcellulose, polyvinylidene fluoride (PVDF), and / or polytetrafluoroethylene (PTFE).

[0046] Separator materials can include polyolefins such as polyethylene (PE) or polypropylene (PP), polyimide (PI), polyethylene terephthalate (PET), polyacrylonitrile (PAN), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), and copolymers. Commercial lithium-ion batteries frequently use polyolefin-based separators, typically made from thin polyethylene (PE) or polypropylene (PP) films. To create a porous structure, the films are often subjected to a stretching process, in which they are stretched significantly in one or more directions. In a typical separator manufacturing process, the films are stretched biaxially.

[0047] To improve safety properties, such as thermal and / or mechanical stability, the stretched films can be additionally coated with a thin ceramic layer on one or both sides. Before the ceramic coating, the stretched films can have a thickness in the range of 5 µm to 50 µm, preferably in the range of 8 µm to 20 µm, and particularly around 10 µm. Materials suitable for the ceramic coating include, for example, Al₂O₃, AlO(OH), SiO₂, TiO₂, ZrO₂, or mixtures thereof. The ceramic coating can be applied, for example, by dip coating or blade coating. For this, a slurry of ceramic particles and suitable binders is mixed in a solvent and applied to the polymer film, after which the solvent is removed.The solvent may include, in particular, aqueous solutions and / or organic solvents, such as isopropanol. The binders may include, in particular, polymers and may be selected, for example, from polyethylene glycol, polyvinyl butyral, carboxymethylcellulose, sodium alginate, polyacrylic acid (PAA), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), and mixtures thereof. Suitable methods for ceramic coating are described, for example, in US 2006 / 0147699 A1, US 11,094,998 B2, and US 2021 / 0159493 A1. Alternatively, the ceramic coating may be applied by sputtering, chemical vapor deposition (CVD), or atomic layer deposition (ALD). The ceramic coating can have a thickness in the range of 0.2 µm to 5 µm, preferably in the range of 0.5 µm to 3 µm.

[0048] The electrolyte solution for a power storage cell can include a lithium salt as a conducting salt and at least one organic solvent.

[0049] The electrolyte solution for a power storage cell can include a sodium salt as a conducting salt and at least one organic solvent.

[0050] In a lithium-ion energy storage cell, the lithium salt may preferably be selected from a group consisting of: LiPF6, LiAsF6, LiClO4, LiCF3SO3, lithium bis(trifluoromethylsulfonyl)amide or combinations thereof.

[0051] In a sodium-ion energy storage cell, the sodium salt may preferably be selected from a group consisting of: NaPF6, NaClO4, Na-bis(trifluoromethane)sulfonimide), Na-bis(fluorosulfonyl)imide, Na-difluoro(oxalato)borate), Na-bis(oxalato)borate or combinations thereof.

[0052] The organic solvent may, in particular, comprise a polar organic solvent. The organic solvent may, in particular, be selected from a group consisting of: C2 to C4 cyclic esters of carbonic acid, for example propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, lactones, for example γ-, δ- and ε-lactone or combinations thereof.

[0053] The present invention also relates to an energy storage cell, configured as a lithium-ion or sodium-ion storage cell. The energy storage cell comprises an anode, a cathode, a separator located between the anode and the cathode, and an electrolyte solution present in the pores of the anode, cathode, and separator. The anode contains an electrochemically active material that expands by at least 5%, preferably at least 10%, more preferably at least 40%, during a charging process from 0% state of charge (SOC) to 50% SOC, for example, graphite, silicon dioxide, silicon, or mixtures thereof. The energy storage cell comprises an electrode winding or an electrode stack. The electrode winding or the electrode stack can be housed in a casing, wherein the electrode winding and the electrode stack comprise the anode, cathode, and separator described above.The electrode winding or electrode stack can extend along a longitudinal axis of the energy storage cell within the housing. The energy storage cell can have a first and a second boundary region extending along the longitudinal axis, and a central region extending between the first and second boundary regions along the longitudinal axis. The first boundary region, the second boundary region, and the central region between them can each have the same extent along the longitudinal axis. After at least 50 charge and discharge cycles (C-rate during charging and discharging at least C / 2, SOC range 0-100%, temperature 25 °C), and following a discharge to the cutoff voltage and a rest period of approximately 24 hours, the energy storage cell exhibits an average concentration of Li+ in both the first and second boundary regions.Na+ in the electrolyte solution, which differs by at most 50%, preferably by at most 40%, and more preferably by at most 20%, with respect to the mean concentration of Li+ or Na+ in the electrolyte solution in the middle range.

[0054] The present invention also relates to the use of an energy storage cell according to the invention, as described above, for fast charging. Fast charging is defined as charging at an average C-rate of at least 1C. The C-rate is the ratio of the charging current of an energy storage cell in amperes (A) to the capacity of the energy storage cell in ampere-hours (Ah). Due to the ratio of R set according to the invention... p,Separator,t-IP / R p,Anode,t-IP The energy storage cells according to the invention can be charged particularly quickly using fast-charging methods without excessive aging of the energy storage cells.

[0055] The present invention also relates to a method for reducing the ratio of R p,Separator,t-IP / R p,Anode,t-IP to a value of 0.33 or less, preferably to a value of 0.1 or less, in a power storage cell, wherein the adjustment of the ratio of R p,Separator,t-IP / R p,Anode,t-IP preferably achieved by reducing the pore flow resistance for the electrolyte solution in the separator R p,Separator,t-IP.

[0056] In the following, aspects of the present invention will be explained in more detail with reference to figures and exemplary embodiments. These show: Fig. 1a) to 1e) schematic cross-sectional drawings of an anode and a cathode with exemplary conducting salt concentrations in the electrolyte solution during a charging process and a discharging process with the formation of areas of different conducting salt concentration in the electrodes, Fig. 2 a graph showing the different conducting salt concentrations in the boundary regions and in a central region of the anode flanked by the boundary regions, Fig. Figure 3 shows a schematic top view of an unrolled anode after opening a power storage cell with the positioning of the samples in the first edge area, second edge area and in the middle area of ​​the anode to determine a spatially resolved conducting salt concentration within the anode. Fig. 4. A graph showing different profiles of the conducting salt concentration in a boundary region of the anode with a time course over a large number of charging and discharging cycles as a function of the ratio of R. p,Separator,t-IP / R p,Anode, t-IP , Fig. 5. A graph showing different anode potential profiles over a large number of charge and discharge cycles as a function of the ratio of R. p,Separator, t-IP / R p,Anode, t-IP , Fig. 6 A schematic cross-sectional drawing of a power storage cell with an electrode winding and electrolyte solution squeezed out of the electrode winding, Fig. 7 a schematic cross-sectional drawing of an anode and a cathode with the flow direction “in-plane” and “through-plane”, Fig. 8a a schematic top view and Fig. 8b a schematic enlarged cross-sectional drawing of a separator with ceramic coating and with microchannels generated in the direction of the in-plane axis, Fig. 9a a schematic representation of the electrolyte flow in a conventional arrangement of anode, separator and cathode with in-plane aligned platelet-shaped electrochemically active anode material and spherical electrochemically active cathode material, and Fig. 9b a schematic representation cross-sectional drawings of the electrolyte flow in an arrangement according to the invention consisting of an anode, separator and cathode.

[0057] In the following, elements with the same function will be given the same reference symbols.

[0058] The Fig. Figures 1a) to 1e) show schematic cross-sectional drawings of exemplary concentrations of the conducting salt in the electrolyte solution in the pores of the anode 2 and the pores of the cathode 3 of an electrode winding of a conventional lithium-ion energy storage cell before charging at a state of charge of 0%. The anode 2 and the cathode 3 are separated from each other by a separator layer 4. An excess of electrolyte solution containing a conducting salt was introduced into the lithium-ion energy storage cell compared to the available pore volume of the anode, the cathode, and the separator layer. Due to the excess of electrolyte solution, a small portion 27 of the electrolyte solution is already located outside the electrode winding. As shown in Fig. As shown in 1a), the concentration of the conducting salt is 1 mol / l. The anode 2 has a first edge region 2A and a second edge region 2C at the respective poles of the lithium-ion storage cell, which flank a centrally located middle region of the anode 2B (poles not in the Fig. (1a) to 1e). Similarly, the cathode 3 has a first edge region of cathode 3A and a second edge region of cathode 3C, which flank a central region of cathode 3B. The respective edge regions and the central regions extend along a longitudinal axis 7 of the energy storage cell 1. Before the start of the charging process, the concentration of the lithium conducting salt is 1 mol / l in all regions of the electrodes of the electrode winding and in the portion 27 of the electrolyte solution located outside the electrode winding. A distance 26 perpendicular to the longitudinal axis 7 between the anode 2 and the cathode 3 across the separator layer 4 is typically a few hundred µm, for example, 200 µm. In contrast, the anode 2, the cathode 3, and the separator 4 extend along the longitudinal axis 7 over a greater distance 25, which is generally at least a few centimeters, for example, at least 3 cm.

[0059] During the fast charging process, which takes place in Fig. As shown in Figure 1b), the volume of the electrochemically active anode material, for example graphite, expands because lithium is intercalated into the anode during the charging process. This expansion of the volume of the electrochemically active anode material causes the electrolyte solution located in the pores of the anode to be displaced from the anode 2, as indicated by arrows 5. Since Li is intercalated at the anode during the charging process, + When lithium is absorbed from the electrolyte solution into the anode, the electrolyte solution there is depleted of lithium conducting salt, with a concentration of, for example, 0.5 mol / l, as in Fig. 1b) shown. As the inventors of the present invention have demonstrated, the electrolyte solution 6 displaced from the anode is therefore also depleted of lithium conducting salt and has a concentration of, for example, 0.5 mol / l. In particular, the electrolyte solution depleted of lithium conducting salt can be displaced from the anode 2 at both ends of the electrode winding, so that the electrolyte solution 6 displaced at both ends of the electrode winding collects outside the electrode winding. In contrast, at the cathode 3, lithium ions are released from the electrochemically active cathode material, resulting in an increased concentration of lithium conducting salt in the electrolyte solution adjacent to the cathode. The concentration of lithium conducting salt there is, for example, 1.5 mol / l.Since the transverse in-plane pore flow resistance for the electrolyte solution along the longitudinal axis 7 is smaller for the anode than for the cathode, and since the volume of the electrochemically active anode material increases, lithium-conducting electrolyte solution 6 is predominantly displaced from the anode.

[0060] Fig. 1c) shows the electrode winding with the anode 2 and the cathode 3 after completion of the in Fig. 1b) shown charging process and after a rest period of at least one hour at a state of charge of 100%. The concentration of lithium conducting salt in the anode 2 and in the cathode 3 has equalized again over the short distance 26 between the anode and cathode by diffusion and is slightly increased compared to the original lithium conducting salt concentration, for example at 1.1 mol / l. In contrast, the concentration of lithium conducting salt in the electrolyte solution 6 displaced from the electrode winding, as shown in Fig. 1b) described, is reduced compared to the original conducting salt concentration and is, for example, approximately 0.5 mol / l.

[0061] Fig. 1d) shows the discharge process of the lithium-ion energy storage cell after the in Fig. 1c) shown. During the discharge process, the processes are reversed compared to the charging process. In particular, the anode 2 Li +off, so that the concentration of lithium conducting salt adjacent to anode 2 increases, while Li +The electrolyte solution at cathode 3 is transferred to the cathode, thus decreasing the lithium conducting salt concentration adjacent to cathode 3. Since the volume of the electrochemically active anode material decreases during the discharge process, electrolyte 6 located outside the electrode winding can simultaneously be drawn into the anode 2, as indicated by arrows 8. Because this electrolyte 6 located outside the electrode winding has only a low lithium conducting salt concentration, regions with different lithium conducting salt concentrations form along the longitudinal axis 7 over a distance 25. For example, the lithium conducting salt concentration can be 1.2 mol / l in the first boundary region 2A and in the second boundary region 2B of the anode, while it is 1.5 mol / l in the central region 2C of the anode 2.

[0062] Fig. The image shows the discharged lithium-ion energy storage cell after at least one hour of rest at a state of charge of 0%. Due to the small distance 26 between the anode and cathode, the different lithium conducting salt concentrations have equalized horizontally along the longitudinal axis 7 by diffusion. However, due to the significantly larger distance 25, a conducting salt gradient exists along the longitudinal axis 7, with the first and second outer regions of the anode 2 and cathode 3 each exhibiting lower conducting salt concentrations of, for example, 0.85 mol / l, while the central regions of the anode and cathode exhibit higher conducting salt concentrations of, for example, 1.15 mol / l. Depending on the size of the distance 25, the conducting salt concentration gradient built up along the longitudinal axis 7 may only equalize after several days, or, at larger distances of 8 or 9 cm, as found in larger cylindrical cells, only within months by diffusion.The uncharged lithium-ion energy storage cell of the . Fig. 1e) will then resume normal operation and a charging process, for example a fast charging process, as in Fig. 1b) shown, subjected to this. As a result, with an increasing number of charge and discharge cycles, an increasing gradient of conducting salt concentration builds up along the longitudinal axis 7 in the conventional energy storage cell. This increasing gradient of conducting salt concentration leads to accelerated aging of the energy storage cell and can, in particular, also lead to lithium plating.

[0063] Fig. Figure 2 shows a graph of experimentally determined lithium electrolyte concentrations along the longitudinal axis of a lithium-ion battery in the anode of conventional batteries. Graphs 12 and 13 show significantly different electrolyte concentrations in conventional batteries. The values ​​labeled 14 and 16, respectively, for graphs 12 and 13 represent the electrolyte concentrations in the first and second boundary regions of the anode, while the values ​​labeled 15 represent the lithium electrolyte concentrations in the central region of the anode.

[0064] Fig. Figure 3 shows a schematic top view of an unwound anode 2 or cathode 3 after opening a power storage cell. The unwound anode 2 can have a length of up to 2.5 m in the electrode winding of the power storage cell. Fig. Figure 3 also shows the distance 25 over which the first edge region 2A, the second edge region 2C, and the intermediate middle region 2B of the anode 2 extend. The width of the anode 2, the distance 25, can be approximately 8 cm. To determine the different concentrations of the conducting salt, for example LiPF6, with spatial resolution along the distance 25, round samples 130A can be taken from the first edge region 2A, round samples 30B from the middle region 2B, and round samples 130C from the second edge region 2C of the anode. Samples 130A, 130B, and 130C each have the same area. The solvent of the electrolyte solution, for example ethylene carbonate, can be determined from these samples using liquid chromatography / mass spectrometry (LC-MS). Furthermore, the amounts of the conducting salt can also be determined from the samples using ion chromatography.To determine the spatially resolved amount of conducting salt in the electrode coil, the cell is discharged to its lower cutoff voltage after cycling and left to rest for one day. The cell is then opened in an argon-filled glovebox, the electrode coil is removed, and unwound approximately halfway. Round electrode samples (called "coins") are then taken using a hole punch (e.g., 12 mm diameter). Coins are taken from the outer areas in the first and second marginal regions, approximately 1 to 2 mm from the edge of the electrode coating, and from the center of the electrode coating. Fifteen coins are taken from each region and placed together in previously dried glass containers. Sampling can theoretically be performed at either the anode or the cathode, but sampling at the cathode is preferable because no distortion of the result due to SEI formation is expected.Five milliliters of dried dimethyl carbonate (DMC) or acetonitrile (ACN) are added to each coin as the extraction solvent, and the glass containers are tightly sealed. The coins are left in the extraction solvent for at least 16 hours, ideally on a shaker plate, to ensure complete extraction of the conducting salt. The concentration of the conducting salt in the extraction solvent is then determined. This is done by taking the average of the concentrations determined for the 15 individual coins. The results of the ion chromatography can be directly compared to the concentrations of the conducting salt at the different positions.

[0065] Fig. Figure 6 schematically shows a cross-sectional view of a conventional lithium-ion battery cell 1 with a housing 20 that contacts the anodes 2 and cathodes 3 of the electrode winding around its circumference. A mandrel 24 is located in the center of the electrode winding. The separator layer 4 is arranged between the anodes 2 and the cathodes 3. Due to the mechanically rigid housing 20, the electrode winding cannot expand perpendicular to the longitudinal axis 7 during charging of the battery cell 1. Because of this tension of the electrode winding within the housing, electrolyte solution 23 with a depleted concentration of lithium conducting salt is displaced from the electrode stack, particularly from the outer regions of the anodes, and collects above and below the electrode stack.The lithium-ion storage cell 1 also has poles 21 and 22, which are electrically contacted by the current collector foils 18 of the anodes 2 or the current collector foils 19 of the cathodes 3.

[0066] Fig. Figure 7 schematically shows in cross-section the sequence of layers in a conventional energy storage cell, with anode current collector 29, anode 2, separator 4, cathode 3, and cathode current collector 34. "Through-plane" refers to the plane perpendicular to the main axis 7 and "in-plane" to the plane parallel to the main axis 7.

[0067] According to the invention, by selectively adjusting the ratio R p,Separator, t-IP / R p,Anode, t-IPThe goal is to ensure that, during the charging process of the storage cell, a similar amount of electrolyte solution with reduced conducting salt concentrations is displaced from the anode via the separator as electrolyte solution with increased conducting salt concentrations is displaced from the cathode via the separator. This reduces or prevents the formation of different conducting salt concentrations in different areas of the electrode.

[0068] The ratio of R p,Separator, t-IP / R p,Anode, t-IP can be influenced by various measures, in particular by reducing the pore flow resistance for the electrolyte solution in the separator R p,Separator, t-IP , an increase in the pore flow resistance for the electrolyte solution in the anode R p,Anode, t-IP or a combination of both measures.

[0069] The present invention therefore further relates to a method for reducing the ratio of R p,Separator, t-IP / R p,Anode, t-IPto a value of 0.33 or less, preferably to a value of 0.1 or less, in a power storage cell.

[0070] According to the invention, the ratio of R is adjusted p,Separator, t-IP / R p,Anode, t-IP by (a) reducing the transverse in-plane pore flow resistance for the electrolyte solution in the separator R p,Separator, t-IP and / or (b) increasing the transverse in-plane pore flow resistance for the electrolyte solution in the anode R p,Anode, t-IP .

[0071] The reduction according to the invention of the transverse in-plane pore flow resistance for the electrolyte solution in the separator R p,Separator,t-IPThis can be achieved, for example, by subjecting suitable polymer films to a stretching process in which they are strongly stretched in one or more directions. The parameters of the stretching process can be adjusted so that the pores created by the stretching exhibit a stronger in-plane orientation. A slight reduction in, for example, the through-plane permeability and / or the mechanical stability of the separator can be accepted in this process.

[0072] Alternatively, the reduction of the transverse in-plane pore flow resistance according to the invention for the electrolyte solution in the separator R can be achieved. p,Separator,t-IPThis is achieved by additionally providing stretched polymer films with a thin ceramic coating on one or both sides, whereby the ceramic coating is applied in such a way that the ceramic material is applied in a specific pattern, leaving, for example, microchannels in the transverse direction. Fig. 8a and Fig. Figure 8b shows a separator 4 with a ceramic coating 4a. The ceramic coating has several in-plane microchannels 33. The dashed line shows the center 28e of the separator 4, and the arrows indicate the flow direction of the electrolyte solution during charging. The microchannels serve to reduce the transverse in-plane pore flow resistance for the electrolyte solution in the separator R. p,Separator,t-IP to reduce and thus facilitate the in-plane electrolyte flow in the separator.

[0073] The width 37b of a microchannel 33 is preferably as small as possible to minimize the loss of ceramic material, and as large as necessary to achieve the desired effect on the transverse in-plane pore flow resistance for the electrolyte solution in the separator R. p,Separator,t-IP to achieve the desired effect on the transverse in-plane pore flow resistance for the electrolyte solution in the separator R. The microchannels 33 can have a width in the range of 1 µm to 10 µm, preferably in the range of 2 µm to 3 µm. The spacing 37a between the microchannels is preferably as small as possible to achieve the desired effect on the transverse in-plane pore flow resistance for the electrolyte solution in the separator R. p,Separator,t-IPThe distance 37a between two parallel microchannels can be 0.1 mm or less, preferably 0.05 mm or less, for example in the range of 10 µm to 50 µm. The microchannels 33 can have a depth corresponding to the thickness 35 of the ceramic coating 4a. Alternatively, the microchannels 33 can also have a shallow depth. If the ceramic coating is applied to both sides of the separator, microchannels can be introduced on both sides.

[0074] Microchannels can be created using various technical methods.

[0075] Microchannels can be created by first applying a thin, structured layer of a release agent in a specific spatial pattern to the separator. This is followed by coating the separator with a ceramic coating material. The release agent is selected to reduce or prevent adhesion of the ceramic coating to the separator material in the coated areas. This allows for the creation of in-plane microchannels in the transverse direction, corresponding to the spatial pattern of the release agent. The release agent can be, for example, a polymer, a wax, or another type of release agent.

[0076] Alternatively, the reduction of the transverse in-plane pore flow resistance according to the invention for the electrolyte solution in the separator R can be achieved. p,Separator,t-IPThis can be achieved through manufacturing processes such as electrospinning of polyethylene or polypropylene, for example. By appropriately selecting process parameters during electrospinning, such as voltage, flow rate, needle-collector spacing, and collector type, the morphology, orientation, and structure of the manufactured separator can be influenced to achieve a spatially anisotropic porosity. A targeted increase in porosity in the transverse direction (in-plane) leads to a reduction, according to the invention, of the transverse in-plane pore flow resistance for the electrolyte solution in the separator R. p,Separator,t-IP . Example of implementation

[0077] The influence of the transverse in-plane pore flow resistance on the formation of an in-plane salt concentration gradient and the anode potential during battery cycling was derived using computer-aided simulations.

[0078] First, a flow simulation was performed. For this purpose, a three-dimensional micro-CT scan was created of a conventional anode and cathode, each covering an area of ​​approximately 70 µm². 2 The detected particle geometries were subtracted from the test volume (volume measured by CT). The resulting geometry of a pore network was obtained. From this, and taking into account the fluid dynamic properties of the electrolyte, the transverse in-plane permeability of the individual layers (anode and cathode) could be determined. For this purpose, different flow velocities were applied within the framework of the microstructure flow simulation, and the pressure increase across the test volume was calculated.

[0079] From the transverse in-plane permeability determined by flow simulation and from porosity values ​​measured by He pycnometry, the following values ​​were obtained for the transverse in-plane pore flow resistance for the electrolyte solution in the anode and in the cathode, respectively: Rp,anode,transversal,in−plane=5⋅1010m−2 Rp, cathode, transversal, in−plane=6⋅1011m−2

[0080] The subsequent simulations of the battery cell were performed in the Abaqus software (Dassault Systèmes) according to the Doyle-Fuller-Newman (DFN) approach on two-dimensional FEM models of the battery cell with coupling of electrochemistry and electrolyte flow (hereinafter referred to as DFN / electrolyte flow simulations). The battery cell was represented as a simplified single-layer 2D model (i.e., a single sequence of the layers anode current collector 29, anode 2, separator 4, cathode 3, cathode current collector 34) (see Fig. 7). “Fully Coupled Thermal-Electrochemical-Structural-Pore Pressure Analysis” was used in Abaqus.

[0081] At the top and bottom edges of the electrode winding, the electrolyte is forced out during cell charging and collects in a free volume between the current collectors, which acts like an overflow reservoir (see Fig. 6) During cell discharge, the electrolyte is drawn back into the electrode winding. It was assumed that all nodes of the model, with the exception of the aforementioned reservoir, are in fixed positions. This assumption stems from the fact that lithium-ion cells are typically housed in a rigid casing or subjected to high external mechanical pressure, preventing outward deformation of the cell. Consequently, changes in the volume of the anode particles are accompanied by changes in porosity and thus electrolyte movement.

[0082] The simulation was based on the following parameters: Layer thickness: • Anode: 70 µm • Cathode: 50 µm • Separator: 12 µm Porosity (discharged cell): • Anode: 0.3 • Cathode: 0.25 • Separator: 0.45 Volume expansion of the electrochemically active electrode materials: • Anode particles: 13% volume change. • Cathode particles: Volume change assumed to be negligible. Salt concentration in the electrolyte: • 0.9 mol / l LiPF6

[0083] The results of the DFN / electrolyte flow simulations of the battery cell are in Fig. 4 and Fig. 5 shown.

[0084] Fig. Figure 4 shows the result of the DFN / electrolyte flow simulation of the conducting salt concentration in a marginal region of the anode over a period of more than 60 hours with a large number of charge and discharge cycles for ratios R. p,Separator,t-IP / R p,Anode,t-IP of 0.1 (solid line), 0.2 (dotted line), 0.33 (gray dashed line), and 10 (black dashed line). At the beginning of the charge and discharge cycles, in all four cases, an initial drop in the lithium conduction salt concentration is observed during charging of the energy storage cell, followed by a rapid increase in the lithium conduction salt concentration in the anode during discharging of the energy storage cell. It can be observed that for a ratio R p,Separator,t-IP / R p,Anode,t-IP From 10 (black dashed line) with each charge and discharge cycle, the concentration of the lithium conducting salt in the edge region of the anode successively decreases from a concentration of less than 200 mol / m³ to below 200 mol / m³. 3decreases. In contrast, it shows that for a ratio R p,Separator,t-IP / R p,Anode,t-IP of 0.33 (grey dashed line) or for a ratio R p,Separator,t-IP / R p,Anode,t-IP from 0.2 (dotted line) the concentration of the lithium conducting salt in the edge region of the anode only reaches a concentration of about 400 mol / m³ 3 or approximately 600 mol / m³ 3 decreases. For a ratio R p,Separator,t-IP / R p,Anode,t-IP At 0.1 (solid line), the concentration of the lithium conducting salt remains constant in the edge region of the anode.

[0085] Fig. Figure 5 shows the result of the DFN simulation with coupled fluid flow, showing the course of the anode potential over a large number of charge and discharge cycles for ratios R. p,Separator,t-IP / R p,Anode,t-IP of 0.1 (solid line), 0.2 (dotted line), 0.33 (gray dashed line), and 10 (black dashed line). It can be observed that for a ratio R p,Separator,t-IP / R p,Anode,t-IPFrom 10 (black dashed line), the anode potential decreases from approximately 43 mV to approximately 35 mV with each charge and discharge cycle. In contrast, it is shown that for a ratio R p,Separator,t-IP / R p,Anode,t-IP of 0.33 (grey dashed line) or for a ratio R p,Separator,t-IP / R p,Anode,t-IP From 0.2 (dotted line), the anode potential decreases to a value of only about 42 mV. For a ratio R p,Separator,t-IP / R p,Anode,t-IP At 0.1 (solid line), the anode potential remains constant.

[0086] This shows that an undesirable decrease in the lithium conducting salt concentration in the edge region of the anode or an undesirable decrease in the anode potential can be achieved by adjusting the ratio R according to the invention. p,Separator,t-IP / R p,Anode,t-IP It can be reduced or prevented.

[0087] The invention is not limited by the description based on the exemplary embodiments. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes every combination of features in the patent claims, even if this feature or combination itself is not explicitly specified in the patent claims or exemplary embodiments. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2006 / 0147699 A1

[0047] US 11,094,998 B2

[0047] US 2021 / 0159493 A1

[0047] Cited non-patent literature

[0000] Lagadec et al, 2018 J. Electrochem. Soc. 165 A1829

[0010]

Claims

Energy storage cell, configured as a lithium-ion storage cell or sodium-ion storage cell, comprising an anode, a cathode, a separator located between the anode and the cathode, and an electrolyte solution arranged in pores of the anode, cathode, and separator, wherein the ratio of Rp,Separator,t-IP / Rp,Anode,t-IP has a value of 0.33 or less, preferably a value of 0.1 or less, wherein Rp,Separator,t-IP is the transverse in-plane pore flow resistance for the electrolyte solution in the separator and corresponds to the quotient of the porosity of the separator and the transverse in-plane permeability for the electrolyte solution in the separator, and Rp,Anode,t-IP is the transverse in-plane pore flow resistance for the electrolyte solution in the anode and corresponds to the quotient of the porosity of the anode and the transverse in-plane permeability for the electrolyte solution in the anode. Energy storage cell according to claim 1, wherein the ratio of Rp,separator,t-IP / Rp,cathode,t-IP has a value of 0.033 or less, preferably a value of 0.01 or less, and wherein Rp,cathode,t-IP is the transverse in-plane pore flow resistance for the electrolyte solution in the cathode and corresponds to the quotient of cathode porosity and transverse in-plane permeability for the electrolyte solution in the cathode. Energy storage cell according to the preceding claim, wherein the anode comprises an electrochemically active anode material selected from the group consisting of: synthetic graphite, natural graphite, graphene, mesocarbon, doped carbon, hard carbon, soft carbon, fullerene, silicon-carbon composites, silicon, surface-coated silicon, silicon suboxide, silicon alloys, aluminum alloys, indium, tin alloys, cobalt alloys and mixtures thereof, further preferably wherein the electrochemically active anode material is selected from the group consisting of: graphite, silicon oxide and silicon and mixtures thereof. Energy storage cell according to one of the preceding claims, wherein the cathode comprises an electrochemically active cathode material selected from the group consisting of: lithium transition metal oxides such as lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese compounds (known by the abbreviation NCM or NMC), for example LiCoO2, LiNi0,33Co0,33Mn0,33O2, lithium nickel cobalt aluminum oxides (NCA), lithium olivines such as lithium iron phosphate (LFP), lithium spinels such as lithium manganese oxide spinel (LMO) or combinations thereof, further preferably wherein the electrochemically active cathode material is selected from the group consisting of: lithium nickel cobalt manganese compounds. Energy storage cell according to one of the preceding claims, wherein the electrolyte solution for a lithium-ion storage cell comprises a lithium salt as a conducting salt and at least one organic solvent, and for a sodium-ion storage cell comprises a sodium salt as a conducting salt and at least one organic solvent, wherein the lithium salt is preferably selected from the group consisting of: LiPF6, LiAsF6, LiClO4, LiCF3SO3, lithium bis(trifluoromethylsulfonyl)amide or combinations thereof, or the sodium salt is preferably selected from the group consisting of: NaPF6, NaClO4, Na-bis(trifluoromethane)sulfonimide, Na-bis(fluorosulfonyl)imide, Na-difluoro(oxalato)borate, Na-bis(oxalato)borate or combinations thereof;and / or wherein the organic solvent comprises a polar organic solvent, preferably wherein the organic solvent is selected from a group consisting of: C2 to C4 cyclic esters of carbonic acid, for example propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate; lactones, for example γ-, δ- and ε-lactone or combinations thereof.; Energy storage cell according to one of the preceding claims, comprising an electrode winding or an electrode stack, wherein the electrode winding or the electrode stack is housed in a casing and comprises the anode, the cathode, the separator and the electrolyte solution, wherein the electrode winding or the electrode stack extends in the casing along a longitudinal axis of the energy storage cell. Energy storage cell according to the preceding claim, wherein the electrode winding or the electrode stack has an extent of at least 3 cm along the longitudinal axis. Energy storage cell according to one of the preceding claims, wherein the porosity of the anode, the cathode and the separator is determined by means of He pycnometry. Energy storage cell, configured as a lithium-ion storage cell or sodium-ion storage cell, comprising an anode, a cathode, a separator located between the anode and the cathode, and an electrolyte solution arranged in pores of the anode, cathode, and separator, wherein the anode comprises an electrochemically active material that expands by at least 5% during a charging process from 0% SOC to 50% SOC, wherein the energy storage cell comprises an electrode winding or an electrode stack, the electrode winding or the electrode stack being housed in a casing and comprising the anode, the cathode, the separator, and the electrolyte solution, wherein the electrode winding or the electrode stack extending in the casing along a longitudinal axis of the energy storage cell, and the anode,The separator and the cathode have a first and a second boundary region extending along the longitudinal axis and a central region extending between the first and second boundary regions along the longitudinal axis, characterized in that, after at least 50 charging and discharging cycles, after a discharge to the cut-off voltage and resting for approximately 24 hours, the mean concentration of Li+ or Na+ in the electrolyte solution differs by at most 50%, preferably by at most 40%, and more preferably by at most 20% in both the first and second boundary regions compared to the mean concentration of Li+ or Na+ in the electrolyte solution in the central region. Use of a power storage cell according to one of the preceding claims for fast charging, wherein fast charging is charging at an average C-rate of at least 1C, wherein C-rate is the ratio of the charging current of a power storage cell in amperes (A) to the capacity of the power storage cell in ampere-hours (Ah). Method for reducing the ratio of Rp,Separator,t-IP / Rp,Anode,t-IP to a value of 0.33 or less, preferably to a value of 0.1 or less, in a power storage cell, configured as a lithium-ion storage cell or sodium-ion storage cell, comprising an anode, a cathode, a separator located between the anode and the cathode, and an electrolyte solution arranged in pores of the anode, cathode, and separator, wherein Rp,Separator,t-IP is the transverse in-plane pore flow resistance for the electrolyte solution in the separator and corresponds to the quotient of the porosity of the separator and the transverse in-plane permeability for the electrolyte solution in the separator, and Rp,Anode,t-IP is the transverse in-plane pore flow resistance for the electrolyte solution in the anode and corresponds to the quotient of the porosity of the anode and the transverse in-plane permeability for the electrolyte solution in the separator. in-plane permeability for the electrolyte solution in the anode corresponds to. Method according to the preceding claim, wherein the adjustment of the ratio of Rp,Separator,t-IP / Rp,Anode,t-IP is achieved by lowering the transverse in-plane pore flow resistance for the electrolyte solution in the separator. Method according to the preceding claim, wherein the reduction of the transverse in-plane pore flow resistance for the electrolyte solution in the separator Rp,Separator,t-IP is achieved by applying a ceramic coating to at least one side of a separator which has one or more in-plane microchannels. Method according to the preceding claim, wherein the microchannels are generated by applying a structured layer of a separating material to a separator, subsequently coating the separator with a ceramic coating material, and selectively removing the ceramic coating material in the area of ​​the structured separating material to generate microchannels. Method according to one of the preceding claims 13 or 14, wherein the microchannels have a width in the range of 1 µm to 10 µm, preferably in the range of 2 µm to 3 µm, and / or wherein the distance between two adjacent microchannels is 0.1 mm or less, preferably 0.05 mm or less, and / or wherein the microchannels have a depth in the range of 1 / 10 to 1 / 1 of the thickness of the separator.

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