Three-electrode battery and manufacturing method thereof

Abstract

The invention provides a three-electrode battery and a manufacturing method thereof, and relates to the technical field of batteries. When the charge state of the reference electrode is adjusted, the three-electrode battery is connected with the first auxiliary electrode, the second auxiliary electrode, the first auxiliary diaphragm and the second auxiliary diaphragm. Wherein the first auxiliary electrode and the first auxiliary diaphragm are sequentially stacked between the first diaphragm and the reference electrode in the preset direction, the second auxiliary diaphragm and the second auxiliary electrode are sequentially stacked between the reference electrode and the second diaphragm in the preset direction, the auxiliary electrodes are connected with a negative electrode of an external circuit, and the reference electrode is connected with a positive electrode of the external circuit. In the process of charging and discharging a loop through an external circuit, a part of lithium ions of the reference electrode can be introduced into the auxiliary electrode, so that the charge state of the reference electrode is adjusted to be a semi-electric state, and the lithium ions of the reference electrode cannot be introduced into the original battery capacity in the process; therefore, the condition that the battery capacity has errors is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a three-electrode battery and a manufacturing method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present disclosure, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art.

[0003] Lithium iron phosphate is used as a reference electrode mainly for in-situ analysis and potential monitoring during the charge and discharge process of the three-electrode battery. Before use, the state of charge (SOC) needs to be adjusted to a half-charged state to ensure that its electrode voltage is in a stable platform area. In the related art, during the battery manufacturing process, the reference electrode and the pole ear connecting the pole piece are respectively connected to an external circuit, and the circuit is charged and discharged through the external circuit, so that the charge state of the reference electrode is adjusted to a half-charged state. However, this will introduce lithium ions of the reference electrode itself into the battery system, which is equivalent to introducing a part of additional lithium ions on the basis of the original battery capacity, which can easily lead to errors in the battery capacity. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a three-electrode battery and a method for manufacturing the same, aiming to solve the technical problem in the related art that when adjusting the charge state of the reference electrode, lithium ions of the reference electrode itself are easily introduced, resulting in errors in the battery capacity.

[0005] To achieve the above objectives, the technical solutions adopted in this application are as follows:

[0006] In a first aspect, an embodiment of the present application provides a three-electrode battery, comprising:

[0007] An electrode assembly, comprising a negative electrode sheet, a first diaphragm, a reference electrode, a second diaphragm and a positive electrode sheet stacked in sequence along a preset direction;

[0008] A packaging body, comprising a first packaging layer and a second packaging layer, wherein an edge of the first packaging layer and an edge of the second packaging layer are connected to form a receiving cavity capable of receiving an electrolyte, and the packaging body encapsulates the electrode assembly through the receiving cavity;

[0009] When adjusting the charge state of the reference electrode, the three-electrode battery connects the first auxiliary electrode, the second auxiliary electrode, the first auxiliary diaphragm and the second auxiliary diaphragm; wherein the first auxiliary electrode and the first auxiliary diaphragm are sequentially stacked between the first diaphragm and the reference electrode along the preset direction, the second auxiliary diaphragm and the second auxiliary electrode are sequentially stacked between the reference electrode and the second diaphragm along the preset direction, the first auxiliary electrode and the second auxiliary electrode are connected to the negative electrode of the external circuit, and the reference electrode is connected to the positive electrode of the external circuit.

[0010] In one embodiment of the first aspect, the three-electrode battery has a first direction, a second direction and a third direction that are perpendicular to each other, the preset direction and the third direction are parallel, the three-electrode battery also includes a positive ear and a negative ear, the positive ear and the negative ear are both connected to one side of the package along the first direction, the reference electrode is located on the other side of the package along the first direction, the positive ear is connected to the positive electrode sheet, and the negative ear is connected to the negative electrode sheet; when adjusting the charge state of the reference electrode, the first auxiliary electrode is located on one side of the package along the second direction, and the second auxiliary electrode is located on the other side of the package along the second direction.

[0011] In one embodiment of the first aspect, the reference electrode includes an aluminum foil layer and a lithium iron phosphate layer, and the two opposite sides of the aluminum foil layer along the third direction are partially coated with the lithium iron phosphate layer, and the first auxiliary electrode and the second auxiliary electrode both include a copper foil layer and a graphite layer, and the two opposite sides of the copper foil layer along the third direction are partially coated with the graphite layer.

[0012] In one of the embodiments of the first aspect, the three-electrode battery also has a projection plane, which is perpendicular to the preset direction; when adjusting the charge state of the reference electrode, the orthographic projection of the graphite layer on the projection plane completely covers the orthographic projection of the lithium iron phosphate layer on the projection plane.

[0013] In one of the embodiments of the first aspect, the three-electrode battery also has a projection plane, which is perpendicular to the preset direction, and the reference electrode is located at the edge of the positive electrode sheet so that the orthographic projection of the positive electrode sheet on the projection plane completely covers the orthographic projection of the lithium iron phosphate layer on the projection plane.

[0014] In one embodiment of the first aspect, the dimensions of the aluminum foil layer and the lithium iron phosphate layer along the second direction are both W1, and the dimension of the positive electrode sheet along the second direction is W2, satisfying: W1<0.05W2.

[0015] In one embodiment of the first aspect, the dimensions of the aluminum foil layer and the lithium iron phosphate layer along the second direction are both W1, and the dimensions of the copper foil layer and the graphite layer along the first direction are both W3, satisfying: W3>W1.

[0016] In a second aspect, an embodiment of the present application provides a method for manufacturing a three-electrode battery as described in any embodiment of the first aspect above, the manufacturing method comprising:

[0017] Obtaining the first packaging layer, the negative electrode sheet, the first diaphragm, the first auxiliary electrode, the first auxiliary diaphragm, the reference electrode, the second auxiliary diaphragm, the second auxiliary electrode, the second diaphragm, the positive electrode sheet and the second packaging layer;

[0018] The first packaging layer, the negative electrode sheet, the first separator, the first auxiliary electrode, the first auxiliary separator, the reference electrode, the second auxiliary separator, the second auxiliary electrode, the second separator, the positive electrode sheet and the second packaging layer are sequentially stacked along the preset direction;

[0019] Connecting the edge of the first packaging layer and the edge of the second packaging layer outside the reference electrode to form a packaging body with a receiving cavity, then injecting electrolyte into the receiving cavity through an opening formed by the edge of the first packaging layer and the edge of the second packaging layer at the reference electrode, and then connecting the edge of the first packaging layer and the edge of the second packaging layer at the reference electrode to close the opening;

[0020] Connecting the first auxiliary electrode to the negative electrode of the external circuit, and connecting the reference electrode to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that the side of the reference electrode facing the negative electrode sheet is in a half-charge state;

[0021] Connecting the second auxiliary electrode to the negative electrode of the external circuit, and connecting the reference electrode to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that the side of the reference electrode facing the positive electrode sheet is in a half-charge state;

[0022] Cut the edge of the package body where the first auxiliary electrode and the second auxiliary electrode are located, then remove the first auxiliary electrode, the first auxiliary diaphragm, the second auxiliary electrode and the second auxiliary diaphragm, and then reconnect the cut edge of the first packaging layer with the edge of the second packaging layer.

[0023] In one embodiment of the second aspect, the step of connecting the first auxiliary electrode to the negative electrode of an external circuit, connecting the reference electrode to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that the side of the reference electrode facing the negative electrode sheet is in a half-charge state comprises:

[0024] Connecting the first auxiliary electrode to a battery testing device as a negative electrode, and connecting the reference electrode to a battery testing device as a positive electrode;

[0025] The circuit is charged by a battery testing device at a preset rate until a cut-off voltage is reached;

[0026] The charging capacity of the reference electrode facing the negative electrode sheet is obtained through a battery testing device, and then the circuit is discharged through the battery testing device at 50% of the charging capacity and the preset rate.

[0027] In one embodiment of the second aspect, the step of connecting the second auxiliary electrode to a negative electrode of an external circuit, connecting the reference electrode to a positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that a side of the reference electrode facing the positive electrode sheet is in a half-charge state comprises:

[0028] Connecting the second auxiliary electrode to a battery testing device as a negative electrode, and connecting the reference electrode to a battery testing device as a positive electrode;

[0029] The circuit is charged by a battery testing device at a preset rate until a cut-off voltage is reached;

[0030] The charging capacity of the reference electrode facing the positive electrode sheet is obtained through a battery testing device, and then the circuit is discharged through the battery testing device at 50% of the charging capacity and the preset rate.

[0031] The beneficial effects of this application are as follows:

[0032] The three-electrode battery provided in the present application is used to connect the first auxiliary electrode, the second auxiliary electrode, the first auxiliary diaphragm and the second auxiliary diaphragm when adjusting the charge state of the reference electrode. The first auxiliary electrode and the first auxiliary diaphragm are sequentially stacked between the first diaphragm and the reference electrode along a preset direction, and the second auxiliary diaphragm and the second auxiliary electrode are sequentially stacked between the reference electrode and the second diaphragm along a preset direction. The first auxiliary electrode and the second auxiliary electrode are connected to the negative electrode of the external circuit, and the reference electrode is connected to the positive electrode of the external circuit, that is, the first auxiliary electrode, the second auxiliary electrode, the first auxiliary diaphragm and the second auxiliary diaphragm are only used when adjusting the charge state of the reference electrode, and do not exist in the final three-electrode battery. In this way, in the process of charging and discharging the loop through the external circuit, a part of the lithium ions of the reference electrode can be introduced into the first auxiliary electrode and the second auxiliary electrode, so as to adjust the charge state of the reference electrode to a half-charge state. In the process, the lithium ions of the reference electrode will not be introduced into the original battery capacity, thereby effectively improving the situation of battery capacity error.

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and understandable, preferred embodiments are specifically listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 A schematic diagram of a simplified assembly structure of a three-electrode battery, a first auxiliary electrode, a second auxiliary electrode, a first auxiliary diaphragm, and a second auxiliary diaphragm in one embodiment of the present application is shown;

[0036] Figure 2 A schematic diagram of a simplified stacked structure of a first packaging layer, a negative electrode sheet, a first diaphragm, a first auxiliary electrode, a first auxiliary diaphragm, a reference electrode, a second auxiliary diaphragm, a second auxiliary electrode, a second diaphragm, a positive electrode sheet, and a second packaging layer in one embodiment of the present application is shown;

[0037] Figure 3 A simplified structural diagram of a three-electrode battery in one embodiment of the present application is shown;

[0038] Figure 4 A schematic diagram of a simplified stacked structure of a first packaging layer, a negative electrode sheet, a first diaphragm, a reference electrode, a second diaphragm, a positive electrode sheet, and a second packaging layer in one embodiment of the present application is shown;

[0039] Figure 5 The schematic diagram shows the process of the manufacturing method in one embodiment of the present application. Figure 1 ;

[0040] Figure 6 The schematic diagram shows the process of the manufacturing method in one embodiment of the present application. Figure 2 ;

[0041] Figure 7 The schematic diagram shows the process of the manufacturing method in one embodiment of the present application. Figure 3 .

[0042] Description of main component symbols:

[0043] 100-three-electrode battery; 110-electrode assembly; 111-negative electrode sheet; 112-first diaphragm; 113-reference electrode; 114-second diaphragm; 115-positive electrode sheet; 120-package; 121-first packaging layer; 122-second packaging layer; 131-positive electrode ear; 132-negative electrode ear; 210-first auxiliary electrode; 220-first auxiliary diaphragm; 230-second auxiliary electrode; 240-second auxiliary diaphragm; S-preset direction; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0044] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0045] In the description of the present application, terms such as "center", "longitudinal", "lateral", "length", "width", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0046] In addition, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0047] In the description of this application, the terms "first", "second", etc. are used to distinguish different objects and cannot be understood as indicating or implying a specific order or a primary and secondary relationship, or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0048] In the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0049] In the description of this application, the term "and / or" indicates that there may be three relationships. For example, A and / or B may indicate that A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0050] In the description of this application, "parallel" includes not only the absolutely parallel situation, but also the roughly parallel situation conventionally recognized in engineering; at the same time, "perpendicular" also includes not only the absolutely perpendicular situation, but also the roughly perpendicular situation conventionally recognized in engineering. For example, if the angle between two directions is 80° to 90°, the two directions can be considered perpendicular; if the angle between two directions is 0° to 10°, the two directions can be considered parallel.

[0051] like Figure 3 As shown, in the first aspect, an embodiment of the present application provides a three-electrode battery 100, which relates to the field of battery technology and is mainly used in electrical devices and energy storage devices.

[0052] Exemplarily, the electrical devices may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may be fuel vehicles, gas vehicles, new energy vehicles, etc. New energy vehicles may be pure electric vehicles, hybrid vehicles, and extended-range vehicles, etc. Spacecraft may be airplanes, rockets, space shuttles, and spacecrafts, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools may be metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. No specific restrictions are made on the types of electrical devices herein.

[0053] Exemplarily, the energy storage device may be an energy storage container, an energy storage power station, etc., and no specific limitation is made to the type of the energy storage device herein.

[0054] like Figures 1 to 4 As shown, the three-electrode battery 100 provided in this embodiment includes: an electrode assembly 110 and a packaging body 120 .

[0055] The electrode assembly 110 includes a negative electrode sheet 111, a first diaphragm 112, a reference electrode 113, a second diaphragm 114, and a positive electrode sheet 115 stacked in sequence along a preset direction S. The package body 120 includes a first package layer 121 and a second package layer 122, and the edge of the first package layer 121 and the edge of the second package layer 122 are connected to form a receiving cavity capable of receiving an electrolyte, and the package body 120 encapsulates the electrode assembly 110 through the receiving cavity. When adjusting the charge state of the reference electrode 113, the three-electrode battery 100 connects the first auxiliary electrode 210, the second auxiliary electrode 230, the first auxiliary diaphragm 220 and the second auxiliary diaphragm 240; wherein, the first auxiliary electrode 210 and the first auxiliary diaphragm 220 are sequentially stacked between the first diaphragm 112 and the reference electrode 113 along a preset direction S, the second auxiliary diaphragm 240 and the second auxiliary electrode 230 are sequentially stacked between the reference electrode 113 and the second diaphragm 114 along a preset direction S, the first auxiliary electrode 210 and the second auxiliary electrode 230 are connected to the negative electrode of the external circuit, and the reference electrode 113 is connected to the positive electrode of the external circuit.

[0056] Exemplarily, the first encapsulation layer 121 and / or the second encapsulation layer 122 may be an aluminum-plastic film, a polypropylene film (PP film for short), a polycarbonate film (PC film for short), etc., and no specific limitation is made herein.

[0057] It can be understood that the three-electrode battery 100 provided in this embodiment is used to connect the first auxiliary electrode 210, the second auxiliary electrode 230, the first auxiliary diaphragm 220 and the second auxiliary diaphragm 240 when adjusting the charge state of the reference electrode 113. Among them, the first auxiliary electrode 210 and the first auxiliary diaphragm 220 are sequentially stacked between the first diaphragm 112 and the reference electrode 113 along the preset direction S, the second auxiliary diaphragm 240 and the second auxiliary electrode 230 are sequentially stacked between the reference electrode 113 and the second diaphragm 114 along the preset direction S, the first auxiliary electrode 210 and the second auxiliary electrode 230 are connected to the negative electrode of the external circuit, and the reference electrode 113 is connected to the positive electrode of the external circuit, that is, the first auxiliary electrode 210, the second auxiliary electrode 230, the first auxiliary diaphragm 220 and the second auxiliary diaphragm 240 are only used when adjusting the charge state of the reference electrode 113, and do not exist in the finally manufactured three-electrode battery 100.

[0058] In this way, in the process of charging and discharging the loop through an external circuit, a part of the lithium ions of the reference electrode 113 can be introduced into the first auxiliary electrode 210 and the second auxiliary electrode 230, so that the charge state of the reference electrode 113 is adjusted to a half-charged state. During the process, the lithium ions of the reference electrode 113 will not be introduced into the original battery capacity, thereby effectively improving the error in the battery capacity.

[0059] like Figure 1 and Figure 3 As shown, in one embodiment, the three-electrode battery 100 has a first direction X, a second direction Y and a third direction Z which are perpendicular to each other, the preset direction S is parallel to the third direction Z, and the three-electrode battery 100 further includes a positive electrode ear 131 and a negative electrode ear 132, the positive electrode ear 131 and the negative electrode ear 132 are both connected to one side of the package 120 along the first direction X, the reference electrode 113 is located on the other side of the package 120 along the first direction X, the positive electrode ear 131 is connected to the positive electrode sheet 115, and the negative electrode ear 132 is connected to the negative electrode sheet 111; when adjusting the charge state of the reference electrode 113, the first auxiliary electrode 210 is located on one side of the package 120 along the second direction Y, and the second auxiliary electrode 230 is located on the other side of the package 120 along the second direction Y. Such an arrangement allows the lithium ions of the reference electrode 113 to be better introduced into the first auxiliary electrode 210 and the second auxiliary electrode 230 when the loop is charged and discharged through an external circuit, thereby adjusting the charge state of the reference electrode 113 to a half-charged state while improving the error in battery capacity.

[0060] Exemplarily, the dimensions of the positive electrode tab 131 and the negative electrode tab 132 along the first direction X are both 49 mm, and the dimensions of the positive electrode tab 131 and the negative electrode tab 132 along the second direction Y are both 10 mm. Of course, other dimensions are also possible and are not specifically limited here.

[0061] In a specific embodiment, the reference electrode 113 includes an aluminum foil layer and a lithium iron phosphate layer, and the two opposite sides of the aluminum foil layer along the third direction Z are locally coated with the lithium iron phosphate layer. The first auxiliary electrode 210 and the second auxiliary electrode 230 both include a copper foil layer and a graphite layer, and the two opposite sides of the copper foil layer along the third direction Z are locally coated with the graphite layer.

[0062] It can be understood that the reference electrode 113 having an aluminum foil layer and a lithium iron phosphate layer serves as a positive electrode when connected to an external circuit, and the first auxiliary electrode 210 and the second auxiliary electrode 230 having a copper foil layer and a graphite layer serve as negative electrodes when connected to an external circuit, thereby forming a complete circuit, which is convenient for the external circuit to charge and discharge it, and to introduce a portion of the lithium ions of the reference electrode 113 into the first auxiliary electrode 210 and the second auxiliary electrode 230, thereby adjusting the charge state of the reference electrode 113 to a half-charged state.

[0063] At the same time, the lithium iron phosphate layer as a positive electrode material has a stable voltage range, and is used to make the reference electrode 113, which can make the potential of the reference electrode 113 more stable and have a longer service life, so that it can be better used for electrochemical analysis such as in-situ analysis and potential monitoring of the three-electrode battery 100.

[0064] Furthermore, the three-electrode battery 100 also has a projection plane, which is perpendicular to the preset direction S; when adjusting the charge state of the reference electrode 113, the positive projection of the graphite layer on the projection plane completely covers the positive projection of the lithium iron phosphate layer on the projection plane, that is, the areas coated with the lithium iron phosphate layer on the two opposite sides of the reference electrode 113 along the third direction Z are completely covered by the graphite layer. In this way, when the circuit is charged and discharged through an external circuit, the lithium ions of the reference electrode 113 can be better introduced into the first auxiliary electrode 210 and the second auxiliary electrode 230, so as to adjust the charge state of the reference electrode 113 to a half-charged state while improving the error in the battery capacity.

[0065] Furthermore, the three-electrode battery 100 also has a projection plane, which is perpendicular to the preset direction S, and the reference electrode 113 is located at the edge of the positive electrode sheet 115, so that the positive projection of the positive electrode sheet 115 on the projection plane completely covers the positive projection of the lithium iron phosphate layer on the projection plane, that is, the areas coated with the lithium iron phosphate layer on the two opposite sides of the reference electrode 113 along the third direction Z are completely covered by the positive electrode sheet 115. In this way, the reference electrode 113 can be better used for electrochemical analysis such as in-situ analysis and potential monitoring of the three-electrode battery 100.

[0066] like Figure 1As shown, illustratively, the size of the aluminum foil layer and the lithium iron phosphate layer along the second direction Y is W1, the size of the positive electrode sheet 115 along the second direction Y is W2, and the following conditions are met: W1<0.05W2, that is, when manufacturing the reference electrode 113, the size of the aluminum foil layer and the lithium iron phosphate layer along the second direction Y is less than 5% of the size of the positive electrode sheet 115 along the second direction Y. The size of the aluminum foil layer and the lithium iron phosphate layer along the second direction Y is W1, and the size of the copper foil layer and the graphite layer along the first direction X is W3, and the following conditions are met: W3>W1, that is, when manufacturing the first auxiliary electrode 210 and the second auxiliary electrode 230, the size of the copper foil layer and the graphite layer along the first direction X is greater than the size of the aluminum foil layer and the lithium iron phosphate layer along the second direction Y.

[0067] For example, when the size of the positive electrode sheet 115 along the second direction Y is 48 mm, and the size of the positive electrode sheet 115 along the first direction X is 55 mm, the sizes of the aluminum foil layer and the lithium iron phosphate layer along the second direction Y can be set to 2 mm, the size of the lithium iron phosphate layer along the first direction X can be 2 mm, the size of the aluminum foil layer along the first direction X can be 40 mm, and the sizes of the copper foil layer and the graphite layer along the first direction X can be 2.5 mm, and the size of the copper foil layer along the second direction Y can be 40 mm.

[0068] Exemplarily, the size of the negative electrode sheet 111 along the first direction X can be 56 mm, the size of the negative electrode sheet 111 along the second direction Y can be 50 mm, the sizes of the first diaphragm 112, the second diaphragm 114, the first auxiliary diaphragm 220, and the second auxiliary diaphragm 240 along the first direction X and the second direction Y can all be 60 mm, the thickness of the first diaphragm 112, the second diaphragm 114, the first auxiliary diaphragm 220 and the second auxiliary diaphragm 240 can be 12 μm, the size of the package 120 along the first direction X can be 110 mm, and the size of the package 120 along the second direction Y can be 80 mm.

[0069] It should be noted that when the three-electrode battery 100 has length, width and thickness, the first direction X is the length direction of the three-electrode battery 100 , the second direction Y is the width direction of the three-electrode battery 100 , and the third direction Z is the thickness direction of the three-electrode battery 100 .

[0070] like Figure 5 As shown, in a second aspect, an embodiment of the present application provides a method for manufacturing a three-electrode battery 100 as in any embodiment of the first aspect above, the manufacturing method comprising the following steps:

[0071] S310, obtaining the first packaging layer 121, the negative electrode sheet 111, the first diaphragm 112, the first auxiliary electrode 210, the first auxiliary diaphragm 220, the reference electrode 113, the second auxiliary diaphragm 240, the second auxiliary electrode 230, the second diaphragm 114, the positive electrode sheet 115 and the second packaging layer 122;

[0072] S320, stacking the first packaging layer 121, the negative electrode sheet 111, the first separator 112, the first auxiliary electrode 210, the first auxiliary separator 220, the reference electrode 113, the second auxiliary separator 240, the second auxiliary electrode 230, the second separator 114, the positive electrode sheet 115 and the second packaging layer 122 in sequence along a preset direction S;

[0073] S330, connecting the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 outside the reference electrode 113 to form a package body 120 having a receiving cavity, then injecting electrolyte into the receiving cavity through an opening formed by the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 at the reference electrode 113, and then connecting the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 at the reference electrode 113 to close the opening;

[0074] S340, connecting the first auxiliary electrode 210 to the negative electrode of the external circuit, and connecting the reference electrode 113 to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit, so that the side of the reference electrode 113 facing the negative electrode sheet 111 is in a half-charge state;

[0075] S350, connecting the second auxiliary electrode 230 to the negative electrode of the external circuit, and connecting the reference electrode 113 to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit, so that the side of the reference electrode 113 facing the positive electrode sheet 115 is in a half-charge state;

[0076] S360, cutting the edge of the package body 120 where the first auxiliary electrode 210 and the second auxiliary electrode 230 are located, then taking out the first auxiliary electrode 210, the first auxiliary diaphragm 220, the second auxiliary electrode 230 and the second auxiliary diaphragm 240, and then reconnecting the cut edge of the first packaging layer 121 and the edge of the second packaging layer 122.

[0077] Exemplarily, the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 may be connected by heat sealing, welding, bonding, clamping, etc., which is not specifically limited here.

[0078] It can be understood that in the method for manufacturing the three-electrode battery 100 provided in this embodiment, S310 is executed to obtain the first encapsulation layer 121, the negative electrode sheet 111, the first diaphragm 112, the first auxiliary electrode 210, the first auxiliary diaphragm 220, the reference electrode 113, the second auxiliary diaphragm 240, the second auxiliary electrode 230, the second diaphragm 114, the positive electrode sheet 115 and the second encapsulation layer 122. S320 is executed to stack the first encapsulation layer 121, the negative electrode sheet 111, the first diaphragm 112, the first auxiliary electrode 210, the first auxiliary diaphragm 220, the reference electrode 113, the second auxiliary diaphragm 240, the second auxiliary electrode 230, the second diaphragm 114, the positive electrode sheet 115 and the second encapsulation layer 122 in sequence along the preset direction S. Execute S330, connect the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 outside the reference electrode 113 to form a package body 120 with a receiving cavity, then inject electrolyte into the receiving cavity through the opening formed by the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 where the reference electrode 113 is located, and then connect the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 where the reference electrode 113 is located to close the opening. Execute S340, connect the first auxiliary electrode 210 to the negative electrode of the external circuit, and connect the reference electrode 113 to the positive electrode of the external circuit, and then charge and discharge the circuit through the external circuit so that the side of the reference electrode 113 facing the negative electrode sheet 111 is in a half-electric state. Execute S350, connect the second auxiliary electrode 230 to the negative electrode of the external circuit, connect the reference electrode 113 to the positive electrode of the external circuit, and then charge and discharge the loop through the external circuit so that the side of the reference electrode 113 facing the positive electrode sheet 115 is in a half-charged state.

[0079] Thereby, the charge state of the reference electrode 113 is adjusted to a half-charge state.

[0080] Furthermore, after executing S320 to S350, that is, adjusting the charge state of the reference electrode 113 to a half-charged state, execute S360 to cut the edges of the package body 120 where the first auxiliary electrode 210 and the second auxiliary electrode 230 are located, and then take out the first auxiliary electrode 210, the first auxiliary diaphragm 220, the second auxiliary electrode 230 and the second auxiliary diaphragm 240, and then reconnect the cut edge of the first packaging layer 121 and the edge of the second packaging layer 122 to obtain the final three-electrode battery 100.

[0081] Since the first auxiliary electrode 210, the second auxiliary electrode 230, the first auxiliary diaphragm 220 and the second auxiliary diaphragm 240 are only used to adjust the charge state of the reference electrode 113 and do not exist in the final three-electrode battery 100, the lithium ions of the reference electrode 113 will not be introduced into the original battery capacity, thereby effectively improving the situation of battery capacity error. That is, the three-electrode battery 100 obtained by executing S310~S360 has the advantage of smaller battery capacity error.

[0082] It should be noted that the manufacturing method provided in this embodiment is not limited to being executed in the order of S310 to S360, wherein the execution order of S340 and S350 can be exchanged, for example, S340 can be executed first, and then S350, or S350 can be executed first, and then S340, both of which can achieve the purpose of adjusting the charge state of the reference electrode 113 to a half-charged state, and no specific restrictions are made here.

[0083] like Figure 6 As shown, in one embodiment, S340, the first auxiliary electrode 210 is connected to the negative electrode of the external circuit, and the reference electrode 113 is connected to the positive electrode of the external circuit, and then the circuit is charged and discharged through the external circuit so that the side of the reference electrode 113 facing the negative electrode sheet 111 is in a half-charged state, including the following sub-steps:

[0084] S341, connecting the first auxiliary electrode 210 to the battery testing device as a negative electrode, and connecting the reference electrode 113 to the battery testing device as a positive electrode;

[0085] S342, charging the circuit by a battery testing device according to a preset rate until a cut-off voltage is reached;

[0086] S343, obtaining the charging capacity of the reference electrode 113 facing the negative electrode sheet 111 through a battery testing device, and then discharging the loop through the battery testing device at 50% of the charging capacity and a preset rate.

[0087] It is understandable that in the method for manufacturing the three-electrode battery 100 provided in this embodiment, S341 is executed to connect the first auxiliary electrode 210 to the battery testing device as a negative electrode, and the reference electrode 113 is connected to the battery testing device as a positive electrode. S342 is executed to charge the circuit through the battery testing device at a preset rate until the cut-off voltage, so that the first auxiliary electrode 210 continuously plates lithium ions of the reference electrode 113 during the charging process. S343 is executed to obtain the charging capacity of the reference electrode 113 toward the negative electrode sheet 111 side through the battery testing device, and then discharge the circuit through the battery testing device at 50% of the charging capacity and the preset rate, thereby adjusting the reference electrode 113 toward the negative electrode sheet 111 side to a half-electric state.

[0088] It should be noted that the battery testing device is used to provide an external circuit for adjusting the charge state of the reference electrode 113 for the three-electrode battery 100. For example, the preset rate may be 0.05C and the cut-off voltage may be 3.7V, which may be set according to design requirements and are not specifically limited here.

[0089] like Figure 7 As shown, in one embodiment, S350, the second auxiliary electrode 230 is connected to the negative electrode of the external circuit, and the reference electrode 113 is connected to the positive electrode of the external circuit, and then the circuit is charged and discharged through the external circuit so that the side of the reference electrode 113 facing the positive electrode sheet 115 is in a half-charged state, including the following sub-steps:

[0090] S351, connecting the second auxiliary electrode 230 to the battery testing device as a negative electrode, and connecting the reference electrode 113 to the battery testing device as a positive electrode;

[0091] S352, charging the circuit by a battery testing device according to a preset rate until a cut-off voltage is reached;

[0092] S353, obtaining the charging capacity of the reference electrode 113 facing the positive electrode sheet 115 through a battery testing device, and then discharging the circuit through the battery testing device at 50% of the charging capacity and a preset rate.

[0093] It is understandable that in the method for manufacturing the three-electrode battery 100 provided in this embodiment, S351 is executed to connect the second auxiliary electrode 230 to the battery testing device as a negative electrode, and the reference electrode 113 is connected to the battery testing device as a positive electrode. S352 is executed to charge the circuit through the battery testing device at a preset rate until the cut-off voltage, so that the second auxiliary electrode 230 continuously plates the lithium ions of the reference electrode 113 during the charging process. S353 is executed to obtain the charging capacity of the reference electrode 113 toward the positive electrode sheet 115 side through the battery testing device, and then discharge the circuit through the battery testing device at 50% of the charging capacity and the preset rate, thereby adjusting the reference electrode 113 toward the positive electrode sheet 115 side to a half-electric state.

[0094] It should be noted that the battery testing device is used to provide an external circuit for adjusting the charge state of the reference electrode 113 for the three-electrode battery 100. For example, the preset rate may be 0.05C and the cut-off voltage may be 3.7V, which may be set according to design requirements and are not specifically limited here.

[0095] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0096] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A three-electrode battery, characterized in that: include: An electrode assembly, comprising a negative electrode sheet, a first diaphragm, a reference electrode, a second diaphragm and a positive electrode sheet stacked in sequence along a preset direction; A packaging body, comprising a first packaging layer and a second packaging layer, wherein an edge of the first packaging layer and an edge of the second packaging layer are connected to form a receiving cavity capable of receiving an electrolyte, and the packaging body encapsulates the electrode assembly through the receiving cavity; When adjusting the charge state of the reference electrode, the three-electrode battery connects the first auxiliary electrode, the second auxiliary electrode, the first auxiliary diaphragm and the second auxiliary diaphragm; wherein the first auxiliary electrode and the first auxiliary diaphragm are sequentially stacked between the first diaphragm and the reference electrode along the preset direction, the second auxiliary diaphragm and the second auxiliary electrode are sequentially stacked between the reference electrode and the second diaphragm along the preset direction, the first auxiliary electrode and the second auxiliary electrode are connected to the negative electrode of the external circuit, and the reference electrode is connected to the positive electrode of the external circuit.

2. The three-electrode battery according to claim 1, characterized in that: The three-electrode battery has a first direction, a second direction and a third direction which are perpendicular to each other, the preset direction and the third direction are parallel, the three-electrode battery also includes a positive electrode ear and a negative electrode ear, the positive electrode ear and the negative electrode ear are both connected to one side of the package along the first direction, the reference electrode is located on the other side of the package along the first direction, the positive electrode ear is connected to the positive electrode sheet, and the negative electrode ear is connected to the negative electrode sheet; when adjusting the charge state of the reference electrode, the first auxiliary electrode is located on one side of the package along the second direction, and the second auxiliary electrode is located on the other side of the package along the second direction.

3. The three-electrode battery according to claim 2, characterized in that: The reference electrode includes an aluminum foil layer and a lithium iron phosphate layer, and the lithium iron phosphate layer is partially coated on two opposite sides of the aluminum foil layer along the third direction. The first auxiliary electrode and the second auxiliary electrode both include a copper foil layer and a graphite layer, and the graphite layer is partially coated on two opposite sides of the copper foil layer along the third direction.

4. The three-electrode battery according to claim 3, characterized in that: The three-electrode battery also has a projection plane, which is perpendicular to the preset direction; when adjusting the charge state of the reference electrode, the orthographic projection of the graphite layer on the projection plane completely covers the orthographic projection of the lithium iron phosphate layer on the projection plane.

5. The three-electrode battery according to claim 3, characterized in that: The three-electrode battery also has a projection plane, which is perpendicular to the preset direction. The reference electrode is located at the edge of the positive electrode sheet so that the orthographic projection of the positive electrode sheet on the projection plane completely covers the orthographic projection of the lithium iron phosphate layer on the projection plane.

6. The three-electrode battery according to claim 3, characterized in that: The dimensions of the aluminum foil layer and the lithium iron phosphate layer along the second direction are both W1, and the dimension of the positive electrode sheet along the second direction is W2, satisfying: W1<0.05W2.

7. The three-electrode battery according to claim 3, characterized in that: The sizes of the aluminum foil layer and the lithium iron phosphate layer along the second direction are both W1, and the sizes of the copper foil layer and the graphite layer along the first direction are both W3, satisfying: W3>W1.

8. A method for manufacturing a three-electrode battery as claimed in any one of claims 1 to 7, characterized in that: The production method comprises: Obtaining the first packaging layer, the negative electrode sheet, the first diaphragm, the first auxiliary electrode, the first auxiliary diaphragm, the reference electrode, the second auxiliary diaphragm, the second auxiliary electrode, the second diaphragm, the positive electrode sheet and the second packaging layer; The first packaging layer, the negative electrode sheet, the first separator, the first auxiliary electrode, the first auxiliary separator, the reference electrode, the second auxiliary separator, the second auxiliary electrode, the second separator, the positive electrode sheet and the second packaging layer are sequentially stacked along the preset direction; Connecting the edge of the first packaging layer and the edge of the second packaging layer outside the reference electrode to form a packaging body with a receiving cavity, then injecting electrolyte into the receiving cavity through an opening formed by the edge of the first packaging layer and the edge of the second packaging layer at the reference electrode, and then connecting the edge of the first packaging layer and the edge of the second packaging layer at the reference electrode to close the opening; Connecting the first auxiliary electrode to the negative electrode of the external circuit, and connecting the reference electrode to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that the side of the reference electrode facing the negative electrode sheet is in a half-charge state; Connecting the second auxiliary electrode to the negative electrode of the external circuit, and connecting the reference electrode to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that the side of the reference electrode facing the positive electrode sheet is in a half-charge state; Cut the edge of the package body where the first auxiliary electrode and the second auxiliary electrode are located, then remove the first auxiliary electrode, the first auxiliary diaphragm, the second auxiliary electrode and the second auxiliary diaphragm, and then reconnect the cut edge of the first packaging layer with the edge of the second packaging layer.

9. The method for manufacturing a three-electrode battery according to claim 8, characterized in that: The method of connecting the first auxiliary electrode to the negative electrode of the external circuit and the reference electrode to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that the side of the reference electrode facing the negative electrode sheet is in a half-charge state, comprises: Connecting the first auxiliary electrode to a battery testing device as a negative electrode, and connecting the reference electrode to a battery testing device as a positive electrode; The circuit is charged by a battery testing device at a preset rate until a cut-off voltage is reached; The charging capacity of the reference electrode facing the negative electrode sheet is obtained through a battery testing device, and then the circuit is discharged through the battery testing device at 50% of the charging capacity and the preset rate.

10. The method for manufacturing a three-electrode battery according to claim 8, characterized in that: The step of connecting the second auxiliary electrode to the negative electrode of the external circuit, and connecting the reference electrode to the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit so that the side of the reference electrode facing the positive electrode sheet is in a half-charge state comprises: Connecting the second auxiliary electrode to a battery testing device as a negative electrode, and connecting the reference electrode to a battery testing device as a positive electrode; The circuit is charged by a battery testing device at a preset rate until a cut-off voltage is reached; The charging capacity of the reference electrode facing the positive electrode sheet is obtained through a battery testing device, and then the circuit is discharged through the battery testing device at 50% of the charging capacity and the preset rate.

Images