Method for improving performance of electrochemical cell

Abstract

A method of improving the performance of an electrochemical cell having a first electrode and a second electrode and an electrolyte between the first electrode and the second electrode. The first electrode and the second electrode define a current path, and the method includes providing a varying magnetic field through the battery.

Description

[0001] This invention application is a divisional application based on an invention patent application with an application date of January 6, 2020, application number 202080008389.8 (international application number PCT / EP2020 / 050145) and name “Method for Improving the Performance of Electrochemical Cells”. Field of the Invention

[0002] The present invention relates to the performance of electrochemical cells and, in particular, but not exclusively, to increasing the charge and discharge rate and capacity of electrochemical cells. Background Art

[0003] Electrochemical cells are essential to many electrical systems, especially portable devices such as mobile phones and laptops, and increasingly electric vehicles.

[0004] The portability of an electronic device / vehicle depends on the performance of its battery. It is generally desirable that the battery capacity be large and the charging time be short to increase the ratio of the time that the device / vehicle can operate independently of an external power source to the time that they must be connected to an external power source for charging.

[0005] Electrochemical cells can be selected from a variety of types and configurations based on size, shape, voltage, current, and other requirements. Examples of common cell shapes include pouch cells, cylindrical cells, Swagelok cells, and button cells. Cells can also be connected in battery packs to provide the appropriate voltage and / or current for a specific application.

[0006] If a battery is charged too quickly, a number of undesirable operating conditions may occur; for example: dendrite formation, metal plating, and current hot spots, each of which can potentially increase the likelihood of short circuits and battery damage.

[0007] A common method of rapidly charging a battery while avoiding overcharging is to provide a constant current in a first charging phase until a predetermined voltage is reached in the battery, and then, in a second charging phase, to maintain the voltage constant while the current decays to ensure that the battery reaches capacity. The first charging phase rapidly increases the charge in the battery, and the second charging phase is slower.

[0008] C-rate is a measure of the rate at which a battery charges or discharges. It is the current divided by the capacity, expressed in hours.

[0009] The present invention is designed based on the above considerations. Summary of the invention

[0010] The present invention provides a method of improving the performance of an electrochemical cell having a first electrode and a second electrode and an electrolyte between the first electrode and the second electrode, the first electrode and the second electrode defining a current path, the method comprising providing a varying magnetic field through the cell.

[0011] A changing magnetic field facilitates ion transport in an electrochemical cell, which means that the performance of the battery is improved. Optionally, the battery may include a separator between the electrodes. Ion transport can be improved in the electrolyte and / or the electrodes and / or the separator. A changing magnetic field across the battery means that the magnetic flux in the battery changes in size and / or direction and / or distribution over time.

[0012] One battery characteristic that can be improved using the above methods is the charging speed of the battery. Ion transport in a battery is generally the rate determining process during charging, so aiding ion transport speeds up the charging of the battery. Another battery characteristic that can be improved using the above methods is the discharge rate, since ion transport is improved in a manner similar to that during charging. Another battery characteristic that can be improved using the above methods is the capacity of the battery. This can be achieved by implementing the above methods on a battery during battery formation or during operation.

[0013] The changing magnetic field may be a rotating magnetic field and / or an oscillating magnetic field and / or a pulsed magnetic field.

[0014] The direction of the changing magnetic field may have a component perpendicular to the current path.The direction of the changing magnetic field may have a component parallel to the current path.

[0015] The rotation of the magnetic field may be about an axis having a component perpendicular to the direction of the magnetic field.The rotation of the magnetic field may be about an axis having a component parallel to the direction of the magnetic field.

[0016] The rotation of the magnetic field may be about an axis having a component perpendicular to the direction of the current path. The rotation of the magnetic field may be about an axis having a component parallel to the direction of the current path.

[0017] The rotating magnetic field may be provided by rotating permanent magnets, or temporary magnets, or electromagnets, or may be provided by an array of electromagnets that are activated sequentially to effectively rotate the magnetic field.

[0018] The electrochemical cell can be a battery. The battery can be a button cell, a cylindrical cell, a prismatic cell, or a pouch cell.

[0019] The battery pack may be a positive ion battery pack, and the current path may be the direction of travel of the positive ions. The battery pack may be a lithium ion battery pack. Alternatively, the battery pack may be a negative ion battery pack, and the current path may be the direction of travel of the negative ions.

[0020] The battery may be used to power an electric vehicle, a mobile phone, a laptop, a tablet or other portable or stationary device. The battery may be a fuel cell.

[0021] The electrochemical cell may be part of a battery array consisting of two or more cells.

[0022] The magnetic field can be provided by permanent magnets or temporary magnets or electromagnets.

[0023] The electrolyte may be a solid, liquid or gel. In particular, the electrolyte may be non-aqueous, including organic electrolytes.

[0024] A magnetic field generator may be provided to generate a changing magnetic field. The magnetic field generator may be inside the battery, or outside the battery.

[0025] In another aspect, the present invention provides a charging accelerator for improving the performance of an electrochemical cell. The device is configured to perform the above-mentioned method for improving the performance of an electrochemical cell.

[0026] In another aspect, the present invention provides a method for charging an electrochemical cell, comprising the step of providing a current or voltage from a power source to the cell while performing one of the above methods for improving the performance of an electrochemical cell. In the present disclosure, charging the cell includes causing ions in the cell to move, whether due to the action of a current or voltage or due to the spontaneous movement of the ions.

[0027] In another aspect, the present invention provides a method for discharging an electrochemical cell, the method comprising the step of extracting current or voltage from the cell while performing one of the above methods for improving the performance of an electrochemical cell.

[0028] In another aspect, the present invention provides a method for improving the capacity of an electrochemical cell, the method comprising the following steps: forming an electrochemical cell or performing one of the above methods for improving the performance of an electrochemical cell simultaneously during the operation of the electrochemical cell.

[0029] The present invention includes any combination of the described aspects and preferred features unless such a combination is expressly impermissible or expressly intended to be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Embodiments and experiments illustrating the principles of the present invention will now be discussed with reference to the accompanying drawings, in which:

[0031] Figure 1 A side view of an example arrangement of equipment for improving battery performance is shown.

[0032] FIG. 2 shows a schematic diagram of an example arrangement for improving pouch cell performance. Figure 2A shows a cross-sectional side view, Figure 2B A top view is shown.

[0033] Figure 3 The change in battery capacity over time of a pouch cell is shown when charged from 3.4 V to 4.2 V at 0.841 A until 4.2 V is reached and then maintained at a constant voltage while the current decays and reaches capacity under (i) a varying magnetic field (dashed line) and (ii) a permanent magnetic field (solid line).

[0034] Figure 4 The current and voltage of the pouch cell over time are shown when charged from 3.4 V to 4.2 V at 0.841 A until 4.2 V is reached and then held at a constant voltage while the current decays and reaches capacity in (i) the presence of a rotating magnetic field (dashed line) and (ii) a permanent magnetic field (solid line).

[0035] Figure 5 The change in battery capacity over time of a pouch cell is shown when charging from 3.4 V to 4.2 V at 0.841 A until 4.2 V is reached and then held at a constant voltage while the current decays and reaches capacity in (i) the presence of a rotating magnetic field (dashed line), and (ii) a permanent magnetic field (solid line).

[0036] Figure 6 The charging rate in each cycle of a 400 mAh pouch cell under a rotating magnetic field and a permanent magnetic field is shown.

[0037] Figure 7 The results show that the Figure 6 The time it takes to charge a 400mAh soft-pack battery, as well as the size and properties of the battery used.

[0038] Figure 8 The charging speed of a 200mAh soft-pack battery at 4C under a rotating magnetic field and a permanent magnetic field is shown.

[0039] Fig. 9 The results show that the Figure 8 The time it takes to charge a 200mAh soft pack battery, as well as the size and properties of the battery used.

[0040] FIG. 10 shows a schematic diagram of an example arrangement for improving the performance of a Swagelok type battery. Fig. 10A shows a cross-sectional side view, Fig. 10B A top view is shown.

[0041] Fig.11 The charging speed of LMO / Graphite Swagelok cells at 1C, 2C and 3C under rotating magnetic field and permanent magnetic field is shown.

[0042] Fig.12 The results show that the Fig.11 The time it takes to charge the LMO / graphite Swagelok battery at 1C, 2C, and 3C, as well as the size of the battery used.

[0043] FIG. 13 shows a schematic diagram of an example arrangement for improving the performance of cylindrical batteries. Fig.13A shows a cross-sectional view along line AA, Fig. 13B shows a cross-sectional side view along line BB, Fig. 13C A top view is shown.

[0044] Fig.14 The charging rate over various cycles for a cylindrical 2190 mAh LG 18650 cell under a rotating magnetic field, with the cell oriented in two orientations offset 90 degrees from each other, and under a permanent magnetic field are shown.

[0045] Fig.15 The results show that the battery is oriented in two directions with a 90-degree deviation from each other under a rotating magnetic field and a permanent magnetic field. Fig.14 The cylindrical 2190mAh LG 18650 battery is charged at this time. DETAILED DESCRIPTION

[0046] Various aspects and embodiments of the present invention will now be discussed with reference to the accompanying drawings. Other aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated herein by reference.

[0047] Figure 1 The equipment arrangement shown can be used to improve and monitor the performance of a battery 1 when it is charged or discharged. The battery 1 is located on top of a rotating magnetic field generator 2. The battery 1 is connected to a potentiostat and a computer 3 via terminals 4. The potentiostat controls the potential across the battery 1 and can charge or discharge the battery 1. The computer monitors the current and / or capacity and / or voltage of the battery 1. The rotating magnetic field generator 2 provides a rotating magnetic field that passes through the battery 1.

[0048] This arrangement can be used to test a battery, but when monitoring of the battery 1 is not required, the potentiostat, computer 3 and terminals 4 can be removed and optionally replaced by a power source for charging the battery or a load for discharging it.

[0049] exist Figure 1 In the arrangement, the battery 1 is located on top of the rotating magnetic field generator 2, but in other embodiments of the present invention, the unit 1 and the rotating magnetic field generator 2 can be oriented differently as long as the rotating magnetic field generator 2 is capable of generating a magnetic field passing through the unit 1.

[0050] The rotation of the magnetic field may be about an axis substantially parallel to the direction of the generated magnetic field. For example, the direction of the magnetic field generated in the battery 1 may be substantially parallel to the direction between the magnetic field generator 2 and the battery 1, and the rotation of the magnetic field may be about an axis parallel to the direction between the magnetic field generator 2 and the battery 1, such as Figure 2A and Figure 2B shown.

[0051] Alternatively, the rotation of the magnetic field may be about an axis substantially perpendicular to the direction of the generated magnetic field. For example, the direction of the magnetic field generated in the battery 1 may be substantially perpendicular to the direction between the magnetic field generator 2 and the battery 1, and the rotation of the magnetic field may be about an axis parallel to the direction between the magnetic field generator 2 and the battery 1.

[0052] Figure 1 The rotating magnetic field generator 2 in the arrangement can be replaced by a variable magnetic field generator that generates a variable magnetic field that changes in another way. For example, a variable magnetic field generator can be used to generate a rotating and / or oscillating and / or pulsed magnetic field.

[0053] The following apparatus and method examples illustrate the effect of a varying magnetic field on the charging of several commercially available batteries. All examples show that the time it takes to charge the battery is reduced in the presence of a varying magnetic field. These batteries have different geometries and chemistries and are described in more detail below.

[0054] In the present disclosure, the term "under magnetic field conditions" refers to the presence of a changing magnetic field. In the examples explained below, the results of charging a battery in the presence of a changing magnetic field and a comparative example of a battery in the absence of a changing magnetic field are shown. The only difference between the arrangements used in these examples and the comparative examples is that the magnetic field provided in the comparative example is constant in direction and magnitude, while the magnetic field provided in the examples is variable.

[0055] FIG2 shows an arrangement for improving the performance of a soft pack battery 11. The magnetic field generator 12 generates a magnetic field in a direction parallel to Figure 2A The magnetic field is in the direction indicated by the arrow. Figure 2B The magnetic field passes through the soft pack battery 11.

[0056] The magnetic field is offset from the axis of rotation to ensure that the magnetic flux in the cell varies over time.

[0057] The magnetic field generator 12 is an electromagnet powered by a power source 15. The potentiostat 13 is connected to the pouch cell 11, controls the potential across the cell and can be used for charging or discharging the cell.

[0058] The pouch cell 11 is formed of a first electrode and a second electrode separated from each other by an electrolyte. The electrodes are substantially parallel and extend across the length and width of the cell. Each electrode of the pouch cell 11 has a contact that can be connected to a potentiostat, as shown in FIG2 .

[0059] The soft pack battery 11 is oriented so that the direction of the magnetic field passes through the first electrode, the electrolyte and the second electrode of the battery. The direction of the magnetic field is parallel to the direction of the current path between the electrodes. The rotation plane of the magnetic field is parallel to the electrode plane.

[0060] Figure 3 The capacity of the soft pack battery 11 charged when the magnetic field: (i) rotates (shown by the dotted line), and (ii) does not rotate (shown by the solid line) in the presence of a magnetic field generated by the magnetic field generator 12 is shown. The soft pack battery 11 is charged in two stages. In the first stage, the battery is charged from 3.4V to 4.2V at 0.841A until 4.2V is reached, and then in the second stage, the battery is maintained at a constant voltage while the current decays and reaches the capacity.

[0061] The first stage of applying a constant current to the battery can be achieved by Figure 4 The horizontal line portion of the current graph is seen in the middle. In the second stage, the voltage remains constant, the current decays, and full capacity is reached at the same time, which can be seen from where the current changes. The horizontal lines at t = 220 and t = 300 seconds represent the constant current portion of charging under the constant magnetic field and the changing magnetic field, respectively, and the subsequent t represents the constant voltage portion of charging.

[0062] The magnetic field is generated by an electromagnet in the magnetic field generator 12. In the cycle shown by the dotted line, the electromagnet rotates at a speed of 1160 rpm. The results show that the charging time of the battery is reduced by 68% in the presence of a rotating magnetic field.

[0063] Figure 4 Shown in about Figure 3 Current and voltage during charging of the soft pack battery 11 under the conditions described. Again, the dotted line represents charging when the magnetic field rotates, and the solid line represents charging when the magnetic field does not rotate (it is constant). The image shows that in the presence of a rotating magnetic field, the time taken to reach a voltage of 4.2V increases, allowing the first stage of charging, where current is applied, to be maintained for a longer time. Since the first stage of charging increases the charge held by the battery faster than the second stage, this means that overall charging is faster when a rotating magnetic field is present in the battery.

[0064] Figure 5The capacity of the soft pack battery 11 when charging is shown in the presence of a magnetic field generated by the magnetic field generator 12 when the magnetic field (i) rotates (shown by a dotted line) and (ii) does not rotate (shown by a solid line). The soft pack battery 11 is charged in two stages. In the first stage, the battery is charged from 3.4V to 4.2V at 0.841A until 4.2V is reached, and then in the second stage, the battery is maintained at a constant voltage while the current decays and reaches the capacity.

[0065] from Figure 5 It can be seen that in both cycles the battery was charged to 4.2V, but in the cycle where the magnetic field was rotated, the battery's capacity increased by 5%. The rotation of the magnetic field also increased the speed of charging.

[0066] Figure 6 The results of testing the soft pack battery 21 are shown. The soft pack battery 21 has a capacity of 400 mAh and a size of 5 cm by 2 cm by 0.5 cm. The soft pack battery 21 is commercially available through the part information: +PL-402248-2C, 3.7V 400mAh-PO700620140726.

[0067] Figure 6 The charging rate of the soft pack battery 21 for nine charging cycles is shown. Cycles 1 to 3, 7 and 8 are in the presence of a magnetic field rotating at 1170 rpm, and cycle 9 is in the presence of a magnetic field rotating at 1000 rpm. Cycles 4 to 6 are in the presence of a static magnetic field.

[0068] from Figure 6 It can be seen that the charging rate is increased by about 15% by the rotation of the magnetic field.

[0069] Figure 7 The figure shows the time taken to charge the soft pack battery 21 in 8 charging cycles under a rotating magnetic field of 1170 rpm, a rotating magnetic field of 1000 rpm, and a static magnetic field (marked as "no magnetic field" in the figure). Figure 7 It can be seen that in the presence of a rotating magnetic field, the time required to charge the battery is consistently reduced by about 15%.

[0070] Figure 8 The results of testing the soft pack battery 31 are shown. When the capacity of the soft pack battery 31 is 200mAh, the size is 2.5cm x 1.7cm x 0.5cm. The soft pack battery 31 can be purchased through the part information: -PL-651628-2C, 3.7V 210mAh+PO7994.

[0071] Figure 8The charge rate of the pouch cell 31 is shown for two charge cycles. The first cycle is in the presence of a magnetic field rotating at 1160 rpm and the second cycle is in the presence of a static magnetic field.

[0072] from Figure 8 As can be seen in Figure 3, the charging rate is greatly increased by the rotation of the magnetic field.

[0073] Fig. 9 The time taken to charge the soft pack battery 31 in a charging cycle with a rotating magnetic field of 1160 rpm and a static magnetic field (labeled as "no magnetic field" in the figure) is shown. Fig. 9 As can be seen in the graph, the time required to charge the battery at 4C is reduced by 58% in the presence of a rotating magnetic field.

[0074] FIG10 shows an arrangement for improving the performance of a Swagelok type battery 41. The magnetic field generator 42 generates a magnetic field in a direction parallel to Fig. 10A The magnetic field is in the direction indicated by the arrow. Fig. 10B The magnetic field passes through the Swagelok cell 41.

[0075] The magnetic field is offset from the axis of rotation to ensure that the magnetic flux in the cell varies over time.

[0076] The magnetic field generator 42 is an electromagnet powered by a power source 45. A potentiostat 43 is connected to the Swagelok battery 41, controls the potential across the battery and can be used to charge the battery.

[0077] The Swagelok cell 41 is formed of a first electrode and a second electrode separated from each other by an electrolyte and a separator material. The electrodes are substantially parallel and extend across the length and width of the cell. Each electrode of the Swagelok cell 41 has a contact that can be connected to a potentiostat, as shown in FIG. 10 .

[0078] The Swagelok cell 41 is oriented so that the direction of the magnetic field through the cell is perpendicular to the direction of the current path between the electrodes. The plane of rotation of the magnetic field is perpendicular to the plane of the electrodes.

[0079] Fig.11 The test results of Swagelok cell 51 are shown. The dimensions of Swagelok cell 51 are 5 cm by 2.5 cm. Swagelok cell 51 is commercially available as an LMO / graphite Swagelok cell.

[0080] Fig.11 The charge rate of a Swagelok battery 51 is shown for charge cycles at 1C, 2C, and 3C, each cycle in the presence of a rotating magnetic field and in the presence of a static magnetic field (labeled as no magnetic field in the figure). The speed of the rotating magnetic field is 1100 rpm.

[0081] from Fig.11 It can be seen that the charging rate is increased uniformly by the rotation of the magnetic field.

[0082] Fig.12 The time taken to charge a Swagelok battery 51 in 1C, 2C, and 3C charging cycles is shown, each cycle being in the presence of a rotating magnetic field and a static magnetic field (labeled as no magnetic field in the figure). Fig.12 It can be seen that in the presence of a rotating magnetic field, the time taken to charge the battery 51 is consistently reduced.

[0083] FIG13 shows an arrangement for improving the performance of a cylindrical battery 61. The magnetic field generator 62 generates a magnetic field parallel to Fig. 13B The magnetic field is in the direction indicated by the arrow. Fig. 13C The magnetic field passes through the cylindrical battery 61.

[0084] The cylindrical battery 61 is formed by a first electrode and a second electrode separated from each other by an electrolyte. The electrodes are rolled into a spiral configuration and extend through the length of the battery. As shown in Figure 13, each electrode of the cylindrical battery 61 has a contact, which can be connected to a potentiostat.

[0085] The cylindrical battery 61 is oriented in Figure 13 so that the direction of the magnetic field passes through the cross section of the cylinder, perpendicular to the direction between the flat ends of the cylinder. The plane of rotation of the magnetic field is perpendicular to the plane of the cylindrical battery end faces.

[0086] As discussed further below, in other embodiments, the cylindrical battery may alternatively be oriented such that the direction of the magnetic field passes through the ends of the cylindrical unit.

[0087] The magnetic field is offset from the axis of rotation to ensure that the magnetic flux in the cell varies over time.

[0088] The magnetic field generator 62 is an electromagnet powered by a power source 65. A potentiostat 63 is connected to the cylindrical battery 61, controls the potential across the battery and can be used to charge the battery.

[0089] Fig.14 The results of testing a cylindrical cell 71 are shown. The dimensions of the cylindrical cell 71 were 6.5 cm by 1.8 cm. The cylindrical cell 51 is commercially available as a cylindrical 2190 mAh LG 18650 cell.

[0090] Fig.14The charge rates for six charge cycles of cylindrical battery 71 are shown in FIG. Cycles 1 and 2 are in the presence of a magnetic field rotating at 1170 rpm, cycle 5 is in the presence of a magnetic field rotating at 1500 rpm, and cycle 6 is in the presence of a magnetic field rotating at 1200 rpm. Cycles 3 and 4 are in the presence of a static magnetic field. In cycles 5 and 6, the cylindrical battery is positioned with Fig.13A The position shown is oriented at a 90 degree angle so that the flat end of the battery faces the magnetic field generator 62 .

[0091] from Fig.14 It can be seen that in the presence of a rotating magnetic field, the charging rate is generally higher.

[0092] Fig.15 Shown in Fig.14 The time it takes to charge the cylindrical battery 71 in a charging cycle. Fig.15 It can be seen that in the presence of a rotating magnetic field, the time taken to charge the battery 71 is generally lower.

[0093] The principle that the improved ion transport shown in the above examples leads to improved charging rate and / or increased capacity in electrochemical cells can be explained by the reduction of activation energy, which is explained below using a positive ion battery as an example.

[0094] The ionic velocity v in the liquid electrolyte will increase until it is overcome by the resistance F D Overcome. The electric field force F that drives the ions to move E It can be described as:

[0095]

[0096] z i The charge of the ion

[0097] q The elementary charge of an electron (1.6×10 -19 C)

[0098] dV voltage difference

[0099] dx space difference

[0100] The drag force can be approximated using Stokes' law:

[0101] F D =6πμrv Equation 2

[0102] μViscosity of the liquid

[0103] rIonic radius

[0104] vIon speed

[0105] Equating the electric force with the drag determines the final velocity of the ions and thus the mobility, u i :

[0106]

[0107] Mobility affects conductivity via the following equation:

[0108] σ i =(|z i |F)c i u i Equation 5

[0109] c i Molar concentration

[0110] therefore:

[0111] F E ∝u i ∝σ i Equation 6

[0112] In polymer electrolytes, the ohmic resistance σ can be described as:

[0113]

[0114] ΔG act activation energy

[0115] F Faraday constant

[0116] k Boltzmann constant

[0117] Temperature

[0118] therefore:

[0119] F E ∝u i ∝σ i ∝exp(-ΔG act ) Equation 8

[0120] The Maxwell–Faraday equations predict that a time-varying magnetic field δB / δt will always be accompanied by a spatially varying non-conservative electric field E(r, t), which is described as:

[0121]

[0122] Curl operator (infinitesimal rotation of a 3D vector field)

[0123] r-position

[0124] t time

[0125] The electric field E at a given point is defined as the vector electric force F E, for a given charge q:

[0126] F E =qE Equation 10

[0127] Therefore, the effect of the magnetic field on the activation energy is:

[0128] B ∝ E ∝ F E ∝u i ∝σ i ∝exp(-ΔG act ) Equation 11

[0129] Final conductivity and cell resistivity ρ i , related to, so the ohmic potential loss η ohmic ,pass:

[0130]

[0131] Therefore, in the presence of a magnetic field, a polymer membrane conducting positive ions will experience reduced ohmic potential losses through a net reduction in the activation energy associated with the ion mobility accompanying proton transport.

[0132] B∝η ohmic Equation 13

[0133] Magnetic fields can be generated using permanent magnets or electromagnets.

[0134] Using a permanent magnet, in the presence of a magnetic field, a polymer membrane conducting positive ions will experience reduced ohmic potential losses through a net reduction in activation energy.

[0135]

[0136] B Magnetic Induction

[0137] A Cross-sectional area of ​​the plunger

[0138] μ 0 Space Permeability

[0139] Using an electromagnet, in the presence of a magnetic field, a polymer membrane conducting positive ions will experience a reduced loss of ohmic potential through a net reduction in activation energy:

[0140]

[0141] C proportional constant

[0142] A Cross-sectional area of ​​the plunger

[0143] nThe number of turns of the solenoid

[0144] I Current

[0145] l Length of solenoid

[0146] The features disclosed in the preceding description, or in the following claims, or in the accompanying drawings, in their specific form, or expressed in terms of means for performing the disclosed functions, or methods or processes for obtaining the disclosed results, may, where appropriate, be used alone or in any combination of these features to realize the invention in different forms.

[0147] Although the present invention has been described in conjunction with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art when this disclosure is given. Therefore, the exemplary embodiments of the present invention described above are considered to be illustrative rather than restrictive. Various changes may be made to the described embodiments without departing from the spirit and scope of the present invention.

[0148] For the avoidance of any doubt, any theoretical explanations provided herein are intended to improve the reader's understanding. The inventors do not wish to be bound by any of these theoretical explanations.

[0149] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0150] Throughout the specification, including the following claims, unless the context requires otherwise, the words "comprise" and "comprising", and variations such as "which includes", "comprising" and "including", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0151] It must be noted that, as used in the specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when a value is expressed as an approximation by using the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" in relation to a numerical value is optional, and means, for example, + / - 10%.

Claims

1. A method of improving the performance of an electrochemical cell, the electrochemical cell having a first electrode and a second electrode and an electrolyte between the first electrode and the second electrode, the first electrode and the second electrode defining a current path, the method comprising providing a varying magnetic field through the cell. 2 . The method of claim 1 , wherein a direction of the changing magnetic field has a component perpendicular to the current path.

3. The method according to claim 1 or claim 2, wherein the changing magnetic field is a rotating magnetic field.

4. The method of claim 1 or claim 2, wherein the varying magnetic field is an oscillating magnetic field.

5. The method according to claim 1 or claim 2, wherein the changing magnetic field is a pulsed magnetic field.

6. A method according to any preceding claim, wherein the magnetic field rotates about an axis parallel to the current path.

7. A method according to any preceding claim, wherein the electrochemical cell is a battery.

8. The method of claim 6, wherein the battery is a positive ion battery and the current path is the direction of travel of positive ions.

9. A method according to any preceding claim, wherein the magnetic field is provided by a permanent magnet, or a temporary magnet, or an electromagnet.

10. A method according to any preceding claim, wherein the electrolyte is organic.

11. A charging accelerator for improving the performance of an electrochemical battery, the device being configured to perform the method according to any one of claims 1 to 10.

12. A method of charging an electrochemical cell comprising the step of providing a current or voltage from a power source to the cell while carrying out the method according to any one of claims 1 to 10.

13. A method of discharging an electrochemical cell comprising the step of extracting current or voltage from the cell while carrying out the method according to any one of claims 1 to 10.

14. A method of increasing the capacity of an electrochemical cell, comprising the step of forming the electrochemical cell while performing the method according to any one of claims 1 to 10.

15. A method for increasing the capacity of an electrochemical cell, comprising the step of charging or discharging the electrochemical cell while performing the method according to any one of claims 1 to 10.

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