Wiping system for electrodes in electrochemical cells

Abstract

A wiping system for an electrode in an electrochemical cell utilizes: a wiping blade in contact with a surface of the electrode; the blade bracket is provided with a blade mounting seat, the wiping blade is mounted on the blade bracket, and the blade bracket biases the wiping blade to the surface of the electrode so as to provide uniformly distributed contact force between the surface of the wiping blade and the surface of the electrode; the blade bracket is mounted on the translational bracket; a carriage driver on which the carriage is mounted to translate the carriage in a space; and a chassis on which the carriage drive is mounted, the chassis allowing the wiping blade to contact the electrode during operation of the wiping system.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application USSN 63 / 350,051, filed on June 8, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to electrochemical cells, and more particularly to devices and methods for keeping electrodes free of deposits during operation of an electrochemical cell. Background Art

[0004] A typical charge / discharge type electrochemical cell includes a tank containing a liquid electrolyte reservoir, wherein electrodes (cathode and anode) are located, the tank containing a discharge portion generally located at or near the bottom of the tank and a charge portion generally located at or near the top of the tank, with the storage portion located between the charge portion and the discharge portion. The charge portion is used to store electrical energy in the electrochemical cell, and the discharge portion is used to deliver the stored electrical energy to operate an electrical device. The charge portion and the discharge portion are generally not operated simultaneously.

[0005] Charge / discharge type electrochemical cells usually utilize Zn / Zn in an alkaline aqueous electrolyte. 2+ Half-cell reaction. The charging part includes a charging anode and a charging cathode, and the following chemical reactions occur at the charging anode and the charging cathode during the charging operation:

[0006] Charging Anode:

[0007] 4OH - →O2+2H2O+4e -

[0008] Charging cathode:

[0009] Zn(OH)4 2- +2e - →Zn (s) +4OH -

[0010] Solid elemental zinc formed at the charged cathode can be removed from the charged cathode by wiping or scraping. The elemental zinc then theoretically sinks to the bottom of the electrochemical cell under the influence of gravity and collects on the metal current collector, where it is converted back to Zn(OH)4 during the discharge operation of the electrochemical cell. 2-However, known zinc removal systems have one or more disadvantages, including: uneven force distribution on the charging plate, causing zinc to smear on the charging cathode and compact during subsequent wiping cycles, producing a hard, crusty zinc deposit that ultimately causes the wiper / scraper to break; too low normal force relative to the charging cathode, ultimately causing the wiper / scraper to break; too high normal force relative to the charging cathode, causing sticking to the charging cathode; and, high power required to drive the wiping mechanism, reducing the overall efficiency of the system and high parts costs.

[0011] Therefore, in certain types of electrochemical cells, there is a need for a mechanism for efficiently removing deposits of material (e.g., elemental zinc) from an electrode during operation of the electrode without stopping operation, at low cost, and without generating excessive energy parasitics, particularly during operation of the charging cathode during charging operation. Summary of the invention

[0012] A wiping system for an electrode in an electrochemical cell comprises: a wiping blade configured to contact a surface of the electrode; a blade holder having a blade mount on which the wiping blade is mounted, the blade holder being configured to bias the wiping blade toward the surface of the electrode to provide a contact force between the surface of the wiping blade and the surface of the electrode; a translatable bracket on which the blade holder is mounted; a bracket drive on which the bracket is mounted, the bracket drive being configured to translate the bracket in space; and a chassis on which the bracket drive is mounted, the chassis allowing the wiping blade to contact the electrode during operation of the wiping system.

[0013] An electrochemical cell comprises: a can for containing an electrolyte; at least one electrode disposed in the electrolyte, the at least one electrode having a surface on which metal is deposited during operation of the cell; and the above-mentioned wiping system mounted on the can so that the wiping blade contacts the surface on which the metal is deposited and the carriage translates along the electrode.

[0014] The wiping system is suitable for wiping metal deposits on electrodes in an electrochemical cell. The material is preferably an electrodeposited metal, such as zinc, copper, lead, etc. The battery is preferably a charge-discharge electrochemical cell. The electrode is usually a cathode. The wiping system is particularly useful for wiping deposits on a charged cathode. The electrochemical cell includes a tank for containing an electrolyte. At least one electrode, preferably a plurality of electrodes, is arranged in the electrolyte. At least one electrode has a surface on which a material such as a metal is deposited during operation of the battery. The wiping system is mounted on the tank so that the wiping blade contacts the surface on which the material is deposited and the carriage translates along the electrode.

[0015] Compared to many other electrochemical cells that store energy products on electrodes, the wiping mechanism allows the surface of the electrode to be "mechanically dressed or repaired" with each wipe and prevents the long-term surface change effects other cells experience, such as swelling, expansion, deformation and uncontrolled dendrites, leading to degradation / early cycle life failure.

[0016] The wiping system includes a chassis. The chassis is configured to be mounted on an electrochemical cell, preferably on top of the cell on the tank. The chassis provides a mounting seat on which other components of the wiping system can be configured, and acts as an interface between the wiping system and the tank. The chassis allows the wiping system to be aligned with the tank and then with the electrode, so that the wiping blade can contact the electrode during operation of the wiping system. The chassis can be made of any suitable non-conductive material, such as a polymer material such as an engineering plastic (e.g., polyoxymethylene (POM)). The chassis can be a single integral piece or can be composed of multiple parts. The chassis may be part of the tank.

[0017] The carriage driver is mounted on the chassis. The translatable carriage is mounted on the carriage driver. The carriage may include a block of material that can be connected to the carriage driver so that the carriage driver can translate the carriage longitudinally in the chassis. The carriage driver may include any combination of, for example, a drive rod, a motor, a gear, a pulley, a timing belt or a chain, etc. In some embodiments, the carriage driver may be a threaded drive rod (i.e., a lead screw) that is rotationally coupled to the motor so that a complementary internal threaded hole in the carriage engages with the threaded drive rod in cooperation so that the rotation of the drive rod causes the carriage to translate in space along the threaded drive rod. The internal threaded hole may be directly machined into a custom assembly of the carriage driver, or the internal threaded hole may be a thread of a capture nut captured in the carriage. The threaded drive rod may rotate in two rotational directions to be able to translate the carriage toward the front or rear of the chassis. The drive rod may be mounted on one or more bearings mounted in the chassis. The threaded drive rod preferably does not translate relative to the chassis. In other embodiments, a rack and pinion mechanism may be used with a suitable gear that connects the rack or pinion mechanism to the motor. In other embodiments, a timing belt / chain and pulleys may operatively connect the carriage to a motor to drive the carriage on the track. In other embodiments, the carriage driver may be an electric actuator or a hydraulic actuator (e.g., a hydraulic cylinder). The carriage includes appropriate connectors to allow the carriage to be operatively mounted to the carriage driver.

[0018] The wiping system may further include at least one guide rod, preferably at least two guide rods, which are mounted on the chassis in parallel with the drive rod. The translatable carriage may be mounted on at least one guide rod to reduce the rotational motion of the carriage when the carriage is translated on the drive rod. The guide rod reacts to the torque in Mx (tilt moment), My (front / rear cantilever moment) and Mz (rotation around the screw axis). Preferably, the wiping system includes multiple guide rods, such as two guide rods. In some embodiments, the drive rod is centrally positioned along the longitudinal axis of the chassis. Preferably, guide rods are provided on both sides of the chassis in the lateral direction of the drive rod. The guide rod is preferably spaced apart from the drive rod by a distance that prevents the carriage from twisting during translation without causing the carriage to be bound to the guide rod. The carriage may be mounted in the guide rod through a through hole on the carriage, and the guide rod is inserted through the through hole. In order to provide smooth sliding, the through hole has a mechanical fit or bushing insert of linear bearing quality.

[0019] At least one blade holder is mounted on the bracket, preferably rigidly mounted in the direction of motion of the wiper blade stroke, but freely pivotable and slidable transversely to the direction of motion of the wiper blade stroke. Preferably, multiple blade holders, such as 1, 2, 3, 4, 5 or 6 blade holders are mounted on the bracket. In the case of using multiple blade holders, the blade holders are preferably spaced apart from each other transversely relative to the translation direction of the translatable bracket. At least one blade holder preferably extends downward from the bracket into the electrolyte in the tank of the battery. The blade holder can be mounted on the bracket by any suitable method, such as with pins (e.g., bolts, screws, rivets, etc.), welding, gluing, stapling, clamping, etc. The blade holder may include a mounting point through which the blade holder is mounted to the bracket. In some embodiments, the mounting point includes a hole through which the pin can be inserted. Preferably, the blade holder is mounted on the bracket in a manner that enables some lateral and rotational mechanical freedom to accommodate manufacturing misalignments of the electrodes, which would otherwise result in high motor loads (parasitic losses), adhesion and / or fracture. For this reason, a pin-slot arrangement is particularly preferred.

[0020] The blade holder may comprise one or more arms. Preferably, the blade holder is bifurcated and comprises a plurality of arms. More preferably, the blade holder comprises two spaced apart arms. Preferably, the arms meet at a mounting point of the blade holder. The blade holder comprises at least one blade mounting seat to which the wiping blade can be mounted. The wiping blade is a separate component from at least one blade mounting seat to provide rotational freedom and spring preload for the wiping blade. Preferably, each arm comprises a blade mounting seat. In some embodiments, the blade mounting seat comprises a through hole.

[0021] The wiping blade includes a contact surface that contacts the electrode when the wiping blade wipes the electrode. The wiping blade may be arcuate to produce a uniformly distributed normal force distribution on the electrode over the length of the wiping blade when the wiping blade wipes the electrode. The wiping blade also includes a mounting portion to allow the wiping blade to be mounted on a blade holder. The wiping blade may be mounted to the blade mount of the blade holder by any suitable method, such as with pins (e.g., bolts, screws, rivets, etc.), welding, gluing, stapling, clamping, etc. Preferably, the wiping blade is mounted to the blade mount in a manner that the wiping blade has some lateral and rotational mechanical freedom. In some embodiments, the wiping blade includes a U-shaped clip with holes that supports the arm of the blade holder so that the through hole of the blade mount is aligned with the hole in the U-shaped clip, so that the pin can be inserted into the three holes to fix the wiping blade to the blade holder. In a preferred embodiment, the blade holder includes two arms, each of which is mounted with a wiping blade so that the contact surfaces of the two wiping blades are opposite and face each other. In this arrangement, the electrode may be arranged between two wiping blades on the same blade holder so that during a wiping operation, opposite faces of the electrode may be wiped simultaneously by one blade holder.

[0022] The blade holder is configured to bias the wiping blade toward the surface of the electrode to provide a contact force between the wiping blade and the surface of the electrode. The bias can be achieved by an actuator, a spring, etc., but it is simpler and more robust to manufacture the blade holder (including the arm) from an elastic polymer material. When the blade holder comprises an elastic polymer material, the elasticity of the polymer material biases the wiping blade toward the surface of the electrode. The blade holder preferably applies a biasing force to the middle of the wiping blade to balance the load along the wiping blade when the wiping blade contacts the surface of the electrode. When two wiping blades are located on the same blade holder, the two wiping blades are opposite to each other and are biased toward each other by the two arms of the blade holder.

[0023] The blade holder, the wiping blade or both can be made of any suitable non-conductive material capable of withstanding the force of the wiping operation. Preferably, the material is a polymer material, more preferably an engineering plastic, such as an acrylic resin, which has elasticity and can provide the biasing force required to bias the wiping blade toward the surface of the electrode.

[0024] The wiping system is low-cost, simple to operate, and can effectively remove material deposits (e.g., elemental zinc) from electrodes during operation without stopping the operation and without generating excessive energy parasitics. The wiping system is particularly useful for wiping the charged cathode during the charging operation.

[0025] There is a relationship between charging efficiency and wiping frequency. Lower wiping frequencies lead to higher charging efficiencies, so it is desirable to keep the wiping frequency as low as possible, which can also reduce parasitic energy losses from the operation of the wiping system and reduce wear. Optimum cell efficiency comes from a balance of electrolyte concentration, contact force of the wiping blade on the surface of the electrode, wiping frequency, and size of the conductive growth points on the electrode. The wiping system described herein allows for a good balance of these factors to maintain a high charging rate while eliminating uncontrolled dendrite formation at a lower wiping frequency to reduce parasitic energy losses.

[0026] In the following detailed description, further features will be described or made apparent. It should be understood that each feature described herein can be used in any combination with any one or more other described features, and each feature does not necessarily depend on the presence of another feature unless it is obvious to a person skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] For a clearer understanding, preferred embodiments will now be described in detail by way of example with reference to the accompanying drawings, in which:

[0028] Figure 1 is a perspective view of a first embodiment of a wiping system for wiping electrodes in an electrochemical cell.

[0029] Figure 2 yes Figure 1 A perspective view of the wiping system and electrodes in an electrochemical cell is shown.

[0030] Figure 3 yes Figure 2 main view.

[0031] Figure 4 yes Figure 2 Side view of.

[0032] Figure 5 yes Figure 1 A perspective view of the wiping system is shown without the electrodes in the electrochemical cell.

[0033] Figure 6 yes Figure 5 main view.

[0034] Figure 7 yes Figure 5 Side view of.

[0035] Fig. 8A Shows Figure 1 The blade holder of the wipe system.

[0036] Figure 8B Shown for Figure 1 The wiping blade of the wiping system shown.

[0037] Figure 8C Shows Figure 2 The wiping system is suitable for wiping the electrodes.

[0038] Fig. 9 is a graph of wiper blade deflection (mm) versus load (N). Figure 2 The actual performance of the wiping system Figure 2 The finite element analysis (FEA) modeling results of the wiping system are compared.

[0039] Fig.10 is a perspective view of a second embodiment of a wiping system for wiping electrodes in an electrochemical cell.

[0040] Fig.11 yes Fig.11 A perspective view of the wiping system and electrodes of an electrochemical cell is shown.

[0041] Fig.12 yes Fig.11 main view.

[0042] Fig.13 yes Fig.11 Side view of.

[0043] Fig.14 yes Fig.10 A perspective view of the wiping system is shown without the electrodes in the electrochemical cell.

[0044] Fig.15 yes Fig.14 main view.

[0045] Fig.16 yes Fig.14 Side view of.

[0046] Fig.17A Shows Fig.11 The blade holder of the wipe system.

[0047] Fig. 17B Shown for Fig.11 The wiping blade of the wiping system shown.

[0048] Fig. 17C Shows Fig.11 The wiping system is suitable for wiping the electrodes.

[0049] Fig.18 is a graph of wiper blade deflection (mm) versus load (N). Fig.11 The actual performance of the wiping system Fig.11 The finite element analysis (FEA) modeling results of the wiping system are compared.

[0050] Fig.19 is a perspective view of a third embodiment of a wiping system for wiping electrodes in an electrochemical cell.

[0051] Fig. 20 yes Fig.19 The wiping system is suitable for wiping the electrodes.

[0052] Fig.21 is a graph of wiper blade deflection (mm) versus load (N). Fig.19 The actual performance of the wiping system Fig.19 The finite element analysis (FEA) modeling results of the wiping system are compared. DETAILED DESCRIPTION

[0053] refer to Figures 1 to 9 , shows a first embodiment of a wiping system 1 mounted on top of an electrochemical cell 50 (preferably a charge / discharge storage cell). The cell 50 also includes a tank for containing electrolyte and other components commonly found in electrochemical cells. The wiping system 1 includes a chassis 3 having a front mounting block 4a and a rear mounting block 4b, the front mounting block 4a and the rear mounting block 4b being connected together by a guide rod 5 extending longitudinally between the mounting blocks 4a, 4b. Two laterally spaced guide rods 5a, 5b are shown, but any convenient number of guide rods may be employed depending on the size of the chassis 3. The chassis 3 is preferably made of a polymer material, such as an engineering plastic (e.g., polyoxymethylene (POM)). The chassis 3 supports a carriage drive 7, which includes a threaded drive rod 9 extending longitudinally between the mounting blocks 4a, 4b and rotatably connected to a motor 11. The threaded drive rod 9 is mounted on a bearing 13 in the rear mounting block 4b, and the motor 11 is mounted on the front mounting block 4a, so that the carriage drive 7 is mounted on the chassis 3. The motor 11 is preferably electric, but any other motor may be used, such as a pneumatic motor or a hydraulic motor.

[0054] The carriage drive is shown as a threaded drive rod (ie, leadscrew) combination, but as discussed above any suitable drive mechanism may be used.

[0055] The carriage driver 7 supports the carriage 15. The carriage 15 has a through hole therein, and each guide rod 5 and the threaded drive rod 9 extend through the corresponding through hole. The guide rod 5 has a smooth surface, and its respective through hole has a smooth inner surface, so that the carriage 15 can translate smoothly when supported on the guide rod 5. The through hole through which the threaded drive rod 9 extends has a threaded inner surface (e.g., an inner thread of a capture nut), which is engaged with the thread of the threaded drive rod 9. Since the drive rod 9 is threadedly engaged with the threaded inner surface of the through hole through which the drive rod 9 extends, the rotation of the threaded drive rod 9 causes the carriage 15 to translate along the drive rod 9. The threaded drive rod 9 can rotate bidirectionally to drive the carriage 15 to advance and retreat longitudinally, but the threaded drive rod 9 does not translate relative to the chassis 3. The carriage 15 passes through the chassis 3 laterally, and the through hole extends between the front and back of the carriage 15. In the configuration shown, two guide rods 5a, 5b are laterally symmetrically located on either side of a centrally located drive rod 9, and the guide rods 5a, 5b and the drive rod 9 extend longitudinally between the mounting blocks 4a, 4b. The central location of the drive rod 9 allows for smooth translation of the carriage 15 by reducing the torsional forces on the carriage 15 when the threaded drive rod 9 rotates, and the guide rods 5a, 5b further reduce the rotational motion (e.g., torsion) of the carriage 15, so that the carriage 15 can move forward and backward along the drive rod 9 evenly and smoothly. To provide smooth sliding, the through-holes through which the guide rods 5a, 5b extend have linear bearing quality mechanical fits or bushing inserts.

[0056] The bracket 15 provides a mounting seat on which one or more blade holders 21 can be mounted. The blade holders 21 are rigidly connected to the bracket 15, for example, by means of a pin 16 that passes through a slot 17 and extends downwardly from the bracket 15. The slot 17 provides translational and rotational freedom for positioning the pin 16 to accommodate manufacturing misalignment. Four blade holders 21 are shown, but any number of blade holders may be used depending on the configuration and number of electrodes 25. Fig. 8A As shown, each blade holder 21 includes a mounting point 24, at least one arm 22 and at least one blade mounting seat 23 near the end of the arm 22. In the embodiment shown, the blade holder 21 is bifurcated, including a first arm 22a and a second arm 22b spaced apart, and the first arm 22a and the second arm 22b have a first blade mounting seat 23a and a second blade mounting seat 23b, respectively. The two arms 22a, 22b meet at the mounting point 24, which is shown as a hole, and the pin 16 (e.g., a bolt, a screw, a rivet, etc.) can be inserted into the hole to fix the blade holder 21 to the bracket 15. However, any other suitable method can also be used to mount the blade holder 21 to the bracket 15. In addition, in some embodiments, each blade holder can have only one arm.

[0057] Each blade holder 21 supports at least one wiping blade 27 mounted thereon. In this embodiment, the first wiping blade 27a and the second wiping blade 27b are mounted at the first blade mounting seat 23a and the second blade mounting seat 23b on one blade holder 21, respectively. Figure 8B As shown, each wiping blade 27 includes a wiping surface 28 that contacts the surface of the electrode during operation of the wiping system 1 and a mounting U-shaped clip 29 that supports one of the blade holders 23 so that the other pin 26 (see Figure 6 ) can be inserted through the aligned holes of the U-shaped clip 29 and the holes in the blade holder 23 to secure the wiping blade 27 to the blade holder 23. However, any other suitable manner of mounting the wiping blade 27 on the blade mount 23 may be used. In the illustrated embodiment, the wiping surfaces 28 of the first wiping blade 27a and the second wiping blade 27b face each other, so that the opposite sides of one electrode 25 can be wiped by the wiping blades 27 mounted on a single blade holder 21.

[0058] like Figure 2 and Figure 3 As best shown in FIG. 1 , the electrodes 25 are formed of or are strips of material arranged parallel to each other and extending longitudinally between the mounting blocks 4a and 4b. The electrodes 25 include anodes 25a (e.g., charged anodes) and cathodes 25b (e.g., charged cathodes). The anodes 25a and cathodes 25b are laterally alternated. The blade holders 21 are arranged in a row and are laterally spaced relative to the translation direction of the carriage 15, so that each blade holder 21 is sufficiently close to one of the electrodes 25, particularly one of the cathodes 25b, so that the first wiping blade 27a and the second wiping blade 27b wipe two faces of the electrode 25, respectively.

[0059] The first wiping blade 27a and the second wiping blade 27b are respectively opposite to each other and are biased toward each other by the first arm 22a and the second arm 22b. The blade holder 21, including the first arm 22a and the second arm 22b, is made of an elastic polymer material (e.g., an engineering plastic (e.g., an acrylic polymer)), wherein the elasticity of the polymer material biases the wiping surface 28 of the wiping blades 27a, 27b toward the surface of the electrode 25. Other means may also be used to bias the wiping blades 27a, 27b, such as an actuator, a spring, etc., but the use of an elastic polymer material is simpler and stronger. Further, the mounting U-shaped clip 29 of each wiping blade 27 is located in the middle of the wiping blade 27, so that when the wiping surface 28 of the wiping blade 27 contacts the surface of the electrode 25, the arm 22 of the blade holder 21 applies a biasing force to the middle of the wiping blade 27 to balance the load along the wiping blade 27. Furthermore, the wiper blade 27 is arcuate to produce an evenly distributed normal force distribution to the electrode 25 over the length of the wiper blade 27. The wiper blade 27 is also preferably made of a polymer material, such as an engineered plastic (eg, an acrylic polymer).

[0060] Wiping system 1 is best suited for wiping Figure 8C Electrode 25 of the size and configuration shown. Electrode 25, particularly a charging cathode, suitably comprises a conductive metal (e.g., steel) plate 33 (current collector) with graphite particles 32 (only one labeled) inserted into through holes in the metal plate 33 such that the particles 32 protrude from two opposing surfaces of the metal plate 33. Both sides of the metal plate 33 are insulated with a layer of cured epoxy 31, leaving the end faces of the particles 32 exposed but flush with the surface of the cured epoxy layer 31. Smaller holes 34 in the metal plate 33 improve the adhesion between the cured epoxy layer 31 and the metal plate 33. Electrode 25 has high conductivity, low adhesion, easy removal of Zn when the electrode 25 is used as a charging cathode, and easy adjustment of the array of electrochemical cells according to the electrode design requirements of different applications. The surface area, active site distribution, size and shape of the electrode 25 can be easily adjusted to change the operating conditions of different applications. Laboratory tests were conducted using charging cathodes with two graphite diameters (1 mm and 6.35 mm) at variable current density, zincate concentration and wipe interval. The results showed that Zn adhesion was low even at low currents, while the charging efficiency was high at high currents.

[0061] refer to Figures 10 to 18, shows a second embodiment of a wiping system 100 mounted on top of an electrochemical cell 50. The wiping system 100 includes: a chassis 103 having a front mounting block 104a, a rear mounting block 104b and a guide rod 105; a carriage drive 107, the carriage drive 107 including a threaded drive rod 109 and a motor 111; a carriage 115; a blade holder 121, the blade holder 121 including an arm 122 (a first arm 122a and a second arm 122b spaced apart, respectively), the blade holder 121 having a blade mount 123 (a first blade mount 123a and a second blade mount 123b, respectively); a wiping blade 127 (a first wiping blade 127a and a second wiping blade 127b, respectively), the wiping blade 127 having a wiping surface 128 and a mounting U-shaped clip 129. The blade holder 121 is rigidly connected to the bracket 115, for example, by means of a pin 116 passing through a slot 117 and extending downwardly from the bracket 115. The slot 117 provides translational and rotational freedom for positioning the pin 116 to accommodate manufacturing misalignment. The wiping system 100 is the same as the wiping system 1, except that the blade holder 121, while still bifurcated, is slightly different in shape from the blade holder 21, the arm 122 of the blade holder 121 is longer than the arm 22 of the blade holder 21, and the wiping blade 127 is longer than the wiping blade 27, as shown in FIG. Fig.17A and Fig. 17B and Fig. 8A and Figure 8B As can be seen when comparing. Due to the different lengths of the wiping blades 127, the wiping system 100 is suitable for wiping electrodes 125 of different sizes (compare Fig. 17C and Figure 8C ). The electrode 125 also includes a conductive metal (e.g., steel) plate 133 (current collector) in which graphite (cathode) particles 132 (only one is labeled) are inserted into through holes in the metal plate 133 so that the particles 132 protrude from two opposite surfaces of the metal plate 133. Both sides of the metal plate 133 are insulated with a layer of cured epoxy 131, leaving the end faces of the particles 132 exposed but flush with the surface of the cured epoxy layer 131. The smaller holes 134 on the metal plate 133 improve the adhesion between the cured epoxy layer 131 and the metal plate 133.

[0062] refer to Figures 19 to 21The wiping system 200 of the third embodiment includes an integral chassis 203, and a guide rod extends within the chassis 203 between the front and rear of the chassis 203. A bracket drive 207 composed of a threaded drive rod and a motor 211 is installed in the chassis 203. The bracket is mounted on the threaded drive rod, and a blade holder is mounted on the bracket. The blade holder includes an arm 222 (a first arm 222a and a second arm 222b that are spaced apart), a blade mounting seat 223 (a first blade mounting seat 223a and a second blade mounting seat 223b, respectively), and a wiping blade 227 (a first wiping blade 227a and a second wiping blade 227b, respectively). Due to the different lengths of the wiping blades 227, the sizes of the electrodes 225 suitable for wiping by the wiping system 200 are also different (compare Figure 8C and Fig. 17C and Fig. 20 ).

[0063] The operation of the wiping system 200 is the same as that of the wiping system 1 and the wiping system 100, but several design features of the wiping system 200 are different. The wiping system 200 has a higher preload in the wiping blade 227, mainly due to the shape of the blade holder and the longer length of the wiping blade 227, but at the same time has the largest wiping area. Insufficient preload in the wiping area may cause deposits (such as zinc) to smear on the electrode, and these deposits may grow into large continuous blocks and then cause the blade to break. In addition, the chassis 203 of the wiping system 200 is a large integral piece machined from a single piece of material and placed on top of the battery can, which is more expensive. The guide rods are far from the outermost edges of the chassis 203. In contrast, the wiping system 1 and the wiping system 100 have a three-piece design with a wiping blade 27 and a wiping blade 127. The wiping system 1 and the wiping system 100 provide less local stress on the arm 22, the arm 122, the wiping blade 27, and the wiping blade 127. Further, the chassis 3 and chassis 103 of the wiping system 1 and the wiping system 100 are split into a front component and a rear component. Because in order to achieve an ideal guide bushing design (the ratio of the distance between the guide rod and the lead screw and the distance between the two ends of the bushing surface in the front-to-back direction of the bracket), the guide rod 5 and the guide rod 105 are closer to the drive rod 9 and the drive rod 109, and the wiping system 1 and the wiping system 100 reduce or eliminate the restraint of the bracket 15 and the bracket 115 under all load conditions. This reduces the tilting moment (Mx) applied to the bracket 15 and the bracket 115, so that the bracket 15 and the bracket 115 are no longer hindered under high load and / or offset load conditions.

[0064] Wiper blade 227 is 26.5 cm long, wiper blade 127 is 12.5 cm long, and wiper blade 27 is 3.2 cm long. Shorter wiper blades and arms can reduce the "cantilever effect" (My), which introduces a large amount of deflection at the distal end of the wiper blade for a given zinc removal force and reduces the number of zinc spots seen by the wipe, thereby reducing the force experienced by the wipe. Both of these effects can reduce wipe breakage and improve wipe quality. Therefore, the length of the wiper blade is preferably 1.0-15 cm, and more preferably 1.5-12.5 cm.

[0065] The blade holder and wiper blade must be able to handle the required zinc loading scenarios (front / rear loading) and load mounting conditions (arm extension and wiper blade deflection) without yielding under the highest load conditions or fatigued from prolonged use. Finite element analysis of the wiper blade and blade mount arm was used to design the arm and wiper blade to meet these criteria. Empirical testing was performed to obtain the optimal normal force on the wiper blade in Wiping System 1, Wiping System 100, and Wiping System 200 to ensure that the wiping process is as efficient as possible over the required current density and molar concentration range. From Fig. 9 , Fig.18 and Fig.21 It can be seen that for each wiping system, the nominal normal force applied to the electrode was maintained or increased while maintaining or reducing the stress on the arm and wiping blade, thereby reducing high loads and fatigue and eliminating the occurrence of mechanical failure. In addition, for each wiping system, the force deflection of the arm increased linearly, which is consistent with the finite element analysis model, indicating that the wiping system can withstand the force required to wipe zinc from the surface of the electrode without breaking.

[0066] Compared to wiping system 100, wiping system 1 has a lower cantilever load from the bracket to the center of action of the wiping blade, resulting in an evenly distributed normal force, so wiping system 1 is less prone to deflection / fracture during the forward and backward drive action of wiping. Wiping system 1 also allows for reduced electrode cost and reduced battery cube size. However, in some use cases (such as renewable integration), wiping system 100 is more popular than wiping system 1 because of its fast charging function. Therefore, wiping system 1 has lower cost and better reliability due to the smaller cantilever load, but is more suitable for trickle charging in shallow cycle and backup power use cases. Wiping system 200 has a higher and shallower wiping stroke than wiping systems 1 and 100. Since the electrode size follows the battery cube size, and the wiping stroke follows the electrode size, the use of any given embodiment of the wiping system stems from a higher-level strategic decision on the final system packaging and market use cases. The various embodiments described herein enable the charging current range to be adjusted for different applications.

[0067] For those skilled in the art, these novel features will become apparent after reading the specification. However, it should be understood that the scope of the claims should not be limited by the embodiments, but should be given the broadest interpretation consistent with the wording of the claims and the entire specification.

Claims

1. A wiping system for an electrode in an electrochemical cell, the wiping system comprising: a wiping blade configured to contact a surface of the electrode; a blade holder having a blade mount on which the wiper blade is mounted, the blade holder being configured to bias the wiper blade toward a surface of an electrode to provide a contact force between a surface of the wiper blade and a surface of the electrode; a translatable bracket, the blade bracket being mounted on the translatable bracket; a carriage driver, the carriage being mounted on the carriage driver, the carriage driver being configured to translate the carriage in space; as well as A chassis to which the carriage drive is mounted allows the wiping blade to contact an electrode during operation of the wiping system.

2. The system according to claim 1, wherein: The blade holder comprises a resilient polymer material, whereby the resiliency of the polymer material biases the wiper blade toward the surface of the electrode.

3. The system according to claim 1 or 2, wherein: When the wiping blade contacts the surface of the electrode, the blade support applies a biasing force to the middle portion of the wiping blade to balance the load along the wiping blade.

4. The system according to any one of claims 1 to 3, wherein: The wiper blade is arcuate to produce an evenly distributed normal force distribution to the electrode.

5. The system according to any one of claims 1 to 4, wherein: The carriage driver includes a threaded drive rod, and the carriage includes an internally threaded hole, the drive rod being threaded into the threaded hole such that rotation of the drive rod causes the carriage to translate in space along the threaded drive rod.

6. The system according to claim 5, wherein: The threaded drive shaft rotates in both rotational directions but does not translate relative to the chassis.

7. The system according to claim 5 or 6, wherein: The carriage drive includes a motor rotationally coupled to the drive rod to rotate the drive rod.

8. A system according to any one of claims 5 to 7, wherein: The internally threaded hole is provided by a capture nut.

9. The system according to any one of claims 5 to 8 further comprises at least two guide rods mounted on the chassis and parallel to the drive rod, the movable bracket being mounted on at least one guide rod to reduce the rotational movement of the bracket when the bracket translates on the drive rod.

10. The system according to any one of claims 1 to 9, wherein: The blade holder is a first blade holder, and the wiping system comprises at least one other blade holder mounted on the movable carriage, the blade holders being laterally spaced apart from each other relative to a translation direction of the movable carriage.

11. A system according to any one of claims 1 to 10, wherein: The blade holder is bifurcated, the blade holder comprising a first arm and a second arm spaced apart, the first arm and the second arm having a first blade mounting seat and a second blade mounting seat respectively; The wiping blade is a first wiping blade mounted on the first blade mounting seat; The wiping system further comprises a second wiping blade mounted on the second blade mounting seat, Wherein, the first wiping blade and the second wiping blade are opposite to each other and are biased against each other by the first arm and the second arm.

12. An electrochemical cell comprising: a tank for containing electrolytes; at least one electrode disposed in the electrolyte, the at least one electrode having a surface on which the metal is deposited during operation of the cell; and, A wiping system according to any one of claims 1 to 11, mounted to the tank so that the wiping blade contacts the metal deposited surface and the carriage translates along the electrode.

13. The electrochemical cell of claim 12, wherein: The blade holder is bifurcated, the blade holder comprising a first arm and a second arm spaced apart, the first arm and the second arm having a first blade mounting seat and a second blade mounting seat respectively; The wiping blade is a first wiping blade mounted on the first blade mounting seat; The wiping system further comprises a second wiping blade mounted on the second blade mounting seat, Wherein, the first wiping blade and the second wiping blade are opposite to each other and are biased against each other by the first arm and the second arm.

14. The electrochemical cell according to claim 13, wherein: The first wiping blade and the second wiping blade scrape opposing surfaces of the same electrode.

15. The electrochemical cell according to any one of claims 12 to 14, wherein The electrodes include a charged cathode.

16. The electrochemical cell according to any one of claims 12 to 15, wherein The at least one electrode is a plurality of electrodes, and the wiping system comprises a plurality of blade holders mounted on the bracket, each of the blade holders having two wiping blades mounted thereon.

Images