Three-electrode battery and manufacturing method thereof

Abstract

The application provides a three-electrode battery and a manufacturing method thereof, and relates to the technical field of batteries.In the process of adjusting the state of charge of a reference electrode, the three-electrode battery is connected with a first auxiliary electrode, a second auxiliary electrode, a first auxiliary diaphragm and a second auxiliary diaphragm.The first auxiliary electrode and the first auxiliary diaphragm are sequentially stacked between the first diaphragm and the reference electrode along a 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 auxiliary electrode is connected with a negative electrode of an external circuit, the reference electrode is connected with a positive electrode of the external circuit, and in the process of charging and discharging the loop through the external circuit, a part of lithium ions of the reference electrode can be introduced into the auxiliary electrode, the state of charge of the reference electrode is adjusted to a semi-electric state, and in the process, the lithium ions of the reference electrode are not introduced into the original battery capacity, so that the error of the battery capacity is effectively improved.

Description

TECHNICAL FIELD

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

[0002] The information disclosed in this Background section is only for the purpose of enhancing the understanding of the general background of the present disclosure and does not necessarily constitute prior art that is already known to those skilled in the art.

[0003] Lithium iron phosphate as a reference electrode is mainly used for in-situ analysis and potential monitoring in the charging and discharging process of a three-electrode battery. Before use, the state of charge (SOC) needs to be adjusted to half-electric state to ensure that the electrode voltage is in a stable platform region. In the related art, during the manufacturing process of the battery, the reference electrode and the tab of the connecting electrode are respectively connected with an external circuit, and the loop is charged and discharged through the external circuit, so as to adjust the state of charge of the reference electrode to half-electric state. However, this will introduce lithium ions of the reference electrode itself into the battery system, which is equivalent to introducing a part of extra lithium ions on the basis of the original battery capacity, thereby easily leading to errors in the battery capacity. SUMMARY

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

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] In a first aspect, the embodiments of the present application provide a three-electrode battery, comprising:

[0007] an electrode assembly comprising a negative electrode tab, a first separator, a reference electrode, a second separator and a positive electrode tab stacked in sequence along a predetermined direction;

[0008] an encapsulation body comprising a first encapsulation layer and a second encapsulation layer, an edge of the first encapsulation layer and an edge of the second encapsulation layer being connected to form an accommodation cavity capable of accommodating electrolyte, the encapsulation body encapsulating the electrode assembly through the accommodation cavity;

[0009] In the process of adjusting the state of charge of the reference electrode, the three-electrode battery is connected with a first auxiliary electrode, a second auxiliary electrode, a first auxiliary separator and a second auxiliary separator; the first auxiliary electrode and the first auxiliary separator are sequentially stacked between the first separator and the reference electrode along the preset direction, the second auxiliary separator and the second auxiliary electrode are sequentially stacked between the reference electrode and the second separator along the preset direction, the first auxiliary electrode and the second auxiliary electrode are connected with a negative electrode of an external circuit, and the reference electrode is connected with a positive electrode of the external circuit.

[0010] In one of the embodiments of the first aspect, the three-electrode battery has a first direction, a second direction and a third direction which are perpendicular to each other, the preset direction is parallel to the third direction, the three-electrode battery further comprises a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab are both connected to one side of the packaging body along the first direction, the reference electrode is located at the other side of the packaging body along the first direction, the positive electrode tab is connected with the positive electrode sheet, and the negative electrode tab is connected with the negative electrode sheet; in the process of adjusting the state of charge of the reference electrode, the first auxiliary electrode is located at one side of the packaging body along the second direction, and the second auxiliary electrode is located at the other side of the packaging body along the second direction.

[0011] In one of the embodiments of the first aspect, the reference electrode comprises an aluminum foil layer and a lithium iron phosphate layer, the aluminum foil layer is partially coated with the lithium iron phosphate layer on both opposite sides along the third direction, and the first auxiliary electrode and the second auxiliary electrode both comprise a copper foil layer and a graphite layer, the copper foil layer is partially coated with the graphite layer on both opposite sides along the third direction.

[0012] In one of the embodiments of the first aspect, the three-electrode battery further has a projection plane, the projection plane is perpendicular to the preset direction; in the process of adjusting the state of charge of the reference electrode, 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.

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

[0014] In one of the embodiments of the first aspect, the aluminum foil layer and the lithium iron phosphate layer both have a dimension W1 along the second direction, and the positive electrode sheet has a dimension W2 along the second direction, and W1 < 0.05W2 is satisfied.

[0015] In one of the embodiments of the first aspect, the aluminum foil layer and the lithium iron phosphate layer have a size of W1 along the second direction, and the copper foil layer and the graphite layer have a size of W3 along the first direction, and W3> W1.

[0016] In a second aspect, embodiments of the present application provide a manufacturing method of a three-electrode battery as described in any of the embodiments of the first aspect, and the manufacturing method comprises:

[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] stacking 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 in sequence along the preset direction;

[0019] connecting edges of the first packaging layer and edges of the second packaging layer except where the reference electrode is located to form a packaging body having a containing cavity, then injecting an electrolyte into the containing cavity through an opening formed by the edges of the first packaging layer and the edges of the second packaging layer where the reference electrode is located, and then connecting the edges of the first packaging layer and the edges of the second packaging layer where the reference electrode is located to close the opening;

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

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

[0022] cutting edges of the packaging body at the first auxiliary electrode and the second auxiliary electrode, then taking out the first auxiliary electrode, the first auxiliary diaphragm, the second auxiliary electrode, and the second auxiliary diaphragm, and then reconnecting the edges of the first packaging layer and the edges of the second packaging layer that are cut.

[0023] In one embodiment of the second aspect, the connecting the first auxiliary electrode to the negative pole of the external circuit and the connecting the reference electrode to the positive pole of the external circuit, and then charging and discharging the loop through the external circuit to make the side of the reference electrode facing the negative plate in a semi-electric state, comprises:

[0024] connecting the first auxiliary electrode to the negative pole of the battery testing device and the connecting the reference electrode to the positive pole of the battery testing device;

[0025] charging the loop through the battery testing device at a preset rate until the cut-off voltage;

[0026] obtaining the charging capacity of the side of the reference electrode facing the negative plate through the battery testing device, and then discharging the loop through the battery testing device at 50% of the charging capacity and the preset rate.

[0027] In one embodiment of the second aspect, the connecting the second auxiliary electrode to the negative pole of the external circuit and the connecting the reference electrode to the positive pole of the external circuit, and then charging and discharging the loop through the external circuit to make the side of the reference electrode facing the positive plate in a semi-electric state, comprises:

[0028] connecting the second auxiliary electrode to the negative pole of the battery testing device and the connecting the reference electrode to the positive pole of the battery testing device;

[0029] charging the loop through the battery testing device at a preset rate until the cut-off voltage;

[0030] obtaining the charging capacity of the side of the reference electrode facing the positive plate through the battery testing device, and then discharging the loop through the battery testing device at 50% of the charging capacity and the preset rate.

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

[0032] The three-electrode battery provided in the application is used for connecting the first auxiliary electrode, the second auxiliary electrode, the first auxiliary diaphragm and the second auxiliary diaphragm when the charge state of the reference electrode is adjusted, the first auxiliary electrode and the first auxiliary diaphragm are sequentially stacked between the first diaphragm and the reference electrode along a 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 with the negative electrode of the external circuit, and the reference electrode is connected with 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 the charge state of the reference electrode is adjusted, and do not exist in the finally manufactured three-electrode battery. In this way, in the process of charging and discharging the loop through the external circuit, part of the lithium ions of the reference electrode can be introduced into the first auxiliary electrode and the second auxiliary electrode, the charge state of the reference electrode is adjusted to the semi-electric state, and the lithium ions of the reference electrode are not introduced into the original battery capacity in the process, thereby effectively improving the situation that the battery capacity appears errors.

[0033] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the following preferred embodiments are specifically described below, and the detailed description is made below by referring to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

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

[0036] Figure 2 A simple layering structure schematic diagram 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 an embodiment of the application is shown;

[0037] Figure 3 A simple structure schematic diagram of a three-electrode battery in an embodiment of the application is shown;

[0038] Figure 4 A simple layering structure schematic diagram 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 an embodiment of the application is shown;

[0039] Figure 5 Shows a schematic diagram of the process of the manufacturing method in one embodiment of the present application Figure 1 ;

[0040] Figure 6 Shows a schematic diagram of the process of the manufacturing method in one embodiment of the present application Figure 2 ;

[0041] Figure 7 Shows a schematic diagram of 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; 112-first diaphragm; 113-reference electrode; 114-second diaphragm; 115-positive electrode; 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 following describes embodiments of the present application in detail. 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 are not to be construed as limiting the present application.

[0045] In the description of this application, the terms "center", "longitudinal", "lateral", "length", "width", "height", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like 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 this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to this application.

[0046] In addition, unless specifically stated and limited otherwise, a first feature being "on" or "under" a second feature can mean that the first feature is directly in contact with the second feature, or that the first feature is indirectly in contact with the second feature through an intermediate medium. Moreover, the first feature being "over", "above" and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. The first feature being "under", "below" and "underneath" the second feature can mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

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

[0048] In the description of the present application, unless otherwise specifically stated and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0049] In the description of the present application, the term "and / or" indicates that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / ", in general, indicates that the front and rear associated objects are in an "or" relationship.

[0050] In the description of the present application, "parallel" not only includes the case of absolute parallel, but also includes the case of approximate parallel which is generally recognized in engineering; at the same time, "perpendicular" not only includes the case of absolute perpendicular, but also includes the case of approximate perpendicular which is generally recognized in engineering. Illustratively, the included angle between two directions is 80°-90°, which can be considered as the two directions being perpendicular; the included angle between two directions is 0°-10°, which can be considered as the two directions being parallel.

[0051] As shown in Figure 3 In the first aspect, the embodiments of the present application provide a three-electrode battery 100, which relates to the technical field of battery and is mainly applied to power consumption devices and energy storage devices.

[0052] Exemplarily, the electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, or the like. The vehicle can be a fuel automobile, a gas automobile, a new energy automobile, or the like, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, a range extended automobile, or the like. The spacecraft can be an airplane, a rocket, a space shuttle, a spacecraft, or the like. The electric toy includes a fixed or mobile electric toy, for example, a game machine, an electric automobile toy, an electric ship toy, an electric airplane toy, or the like. The electric tool can be a metal cutting electric tool, a grinding electric tool, an assembling electric tool, a railway electric tool, or the like, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, an electric planer, or the like. The type of the electric device is not specifically limited herein.

[0053] Exemplarily, the energy storage device can be an energy storage container, an energy storage power station, or the like. The type of the energy storage device is not specifically limited herein.

[0054] As shown in the figure, the three-electrode battery 100 provided by the embodiment includes an electrode assembly 110 and an encapsulation body 120. Figures 1 to 4

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

[0056] Exemplarily, the first encapsulation layer 121 and / or the second encapsulation layer 122 can be an aluminum plastic film, a polypropylene film (PP film), a polycarbonate film (PC film), or the like. The type of the encapsulation layer is not specifically limited herein.

[0057] ​It will be appreciated 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 state of charge of the reference electrode 113. The first auxiliary electrode 210 and the first auxiliary diaphragm 220 are sequentially stacked along a predetermined direction S between the first diaphragm 112 and the reference electrode 113, and the second auxiliary diaphragm 240 and the second auxiliary electrode 230 are sequentially stacked along a predetermined direction S between the reference electrode 113 and the second diaphragm 114. 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. In other words, 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 state of charge of the reference electrode 113 and are not present in the final three-electrode battery 100.

[0058] In this way, during the process of charging and discharging the loop through an external circuit, a portion 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 situation where errors in the battery capacity occur.

[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 that are perpendicular to each other, and the preset direction S is parallel to the third direction Z. The three-electrode battery 100 further includes a positive electrode tab 131 and a negative electrode tab 132. The positive electrode tab 131 and the negative electrode tab 132 are both connected to one side of the package body 120 along the first direction X. The reference electrode 113 is located on the other side of the package body 120 along the first direction X. The positive electrode tab 131 is connected to the positive electrode sheet 115, and the negative electrode tab 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 body 120 along the second direction Y, and the second auxiliary electrode 230 is located on the other side of the package body 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 the battery capacity.

[0060] Illustratively, 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 one specific embodiment, the reference electrode 113 includes an aluminum foil layer and a lithium iron phosphate layer, the aluminum foil layer is partially coated with the lithium iron phosphate layer on both opposite sides along the third direction Z, the first auxiliary electrode 210 and the second auxiliary electrode 230 each include a copper foil layer and a graphite layer, the copper foil layer is partially coated with the graphite layer on both opposite sides along the third direction Z.

[0062] It can be understood that the reference electrode 113 with the aluminum foil layer and the lithium iron phosphate layer serves as a positive electrode when connecting an external circuit, and the first auxiliary electrode 210 and the second auxiliary electrode 230 with the copper foil layer and the graphite layer serve as negative electrodes when connecting the external circuit, so as to form a complete loop, facilitate the external circuit to charge and discharge, and realize the introduction of part of lithium ions of the reference electrode 113 into the first auxiliary electrode 210 and the second auxiliary electrode 230, thereby adjusting the state of charge of the reference electrode 113 to a semi-electric state.

[0063] Meanwhile, the lithium iron phosphate layer as a positive electrode material has a smooth voltage interval, and is used to make the reference electrode 113, so that the potential of the reference electrode 113 is more stable and the service life is longer, thereby being better used for in-situ analysis, potential monitoring and other electrochemical analysis of the three-electrode battery 100.

[0064] Further, the three-electrode battery 100 also has a projection plane, the projection plane is perpendicular to the preset direction S; when adjusting the state of charge of the reference electrode 113, 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, that is, the region of the reference electrode 113 coated with the lithium iron phosphate layer on both opposite sides along the third direction Z is completely covered by the graphite layer. In this way, when the loop is charged and discharged by the external circuit, lithium ions of the reference electrode 113 can be better introduced into the first auxiliary electrode 210 and the second auxiliary electrode 230, and the state of charge of the reference electrode 113 is adjusted to a semi-electric state while improving the error of the battery capacity.

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

[0066] As Figure 1As shown, 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 positive plate 115 along the second direction Y is W2, which satisfies: W1 < 0.05W2, that is, when the reference electrode 113 is made, 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 plate 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, which satisfies: W3 > W1, that is, when the first auxiliary electrode 210 and the second auxiliary electrode 230 are made, 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 plate 115 along the second direction Y is 48mm, and the size of the positive plate 115 along the first direction X is 55mm, the size of the aluminum foil layer and the lithium iron phosphate layer along the second direction Y can be set to 2mm, the size of the lithium iron phosphate layer along the first direction X can be 2mm, the size of the aluminum foil layer along the first direction X can be 40mm, and the size of the copper foil layer and the graphite layer along the first direction X can be 2.5mm, and the size of the copper foil layer along the second direction Y can be 40mm.

[0068] As an example, the size of the negative plate 111 along the first direction X can be 56mm, the size of the negative plate 111 along the second direction Y can be 50mm, the size of the first separator 112, the second separator 114, the first auxiliary separator 220 and the second auxiliary separator 240 along the first direction X and the second direction Y can be 60mm, the thickness of the first separator 112, the second separator 114, the first auxiliary separator 220 and the second auxiliary separator 240 can be 12μm, the size of the package 120 along the first direction X can be 110mm, and the size of the package 120 along the second direction Y can be 80mm.

[0069] It should be noted that when the three-electrode battery 100 has a length, a width and a 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] As shown in the first aspect, the embodiment of the present application provides a three-electrode battery 100. Figure 5 As shown in the second aspect, the embodiment of the present application provides a manufacturing method of the three-electrode battery 100 in any of the embodiments of the first aspect, which comprises the following steps:

[0071] S310, obtaining the first packaging layer 121, the negative plate 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 plate 115 and the second packaging layer 122;

[0072] S320, sequentially laminating the first encapsulation layer 121, the negative tab 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 tab 115 and the second encapsulation layer 122 in the preset direction S;

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

[0074] S340, connecting the first auxiliary electrode 210 with the negative electrode of the external circuit and connecting the reference electrode 113 with the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit, so that the reference electrode 113 is in a semi-electric state towards the side of the negative tab 111;

[0075] S350, connecting the second auxiliary electrode 230 with the negative electrode of the external circuit and connecting the reference electrode 113 with the positive electrode of the external circuit, and then charging and discharging the circuit through the external circuit, so that the reference electrode 113 is in a semi-electric state towards the side of the positive tab 115;

[0076] S360, cutting the edge of the encapsulation body 120 at the places 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 separator 220, the second auxiliary electrode 230 and the second auxiliary separator 240, and then reconnecting the edge of the first encapsulation layer 121 and the edge of the second encapsulation layer 122 which are cut.

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

[0078] It can be understood that in the manufacturing method of the three-electrode battery 100 provided in the embodiment, S310 is performed to obtain 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. S320 is performed to sequentially stack 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 in the preset direction S. S330 is performed to connect the edges of the first packaging layer 121 and the edges of the second packaging layer 122 except the edges of the first packaging layer 121 and the edges of the second packaging layer 122 where the reference electrode 113 is located to form a packaging body 120 having a containing cavity, then inject an electrolyte into the containing cavity through an opening formed by the edges of the first packaging layer 121 and the edges of the second packaging layer 122 where the reference electrode 113 is located, and then connect the edges of the first packaging layer 121 and the edges of the second packaging layer 122 where the reference electrode 113 is located to close the opening. S340 is performed to connect the first auxiliary electrode 210 to a negative electrode of an external circuit and connect the reference electrode 113 to a positive electrode of the external circuit, and then charge and discharge the circuit through the external circuit to make the reference electrode 113 at a side of the negative electrode sheet 111 in a half-electric state. S350 is performed to connect the second auxiliary electrode 230 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 to make the reference electrode 113 at a side of the positive electrode sheet 115 in the half-electric state.

[0079] Thus, the charging state of the reference electrode 113 is adjusted to the half-electric state.

[0080] Further, after S320-S350, that is, after the charging state of the reference electrode 113 is adjusted to the half-electric state, S360 is performed to shear the edges of the packaging body 120 at the positions of the first auxiliary electrode 210 and the second auxiliary electrode 230, 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 edges of the first packaging layer 121 and the edges of the second packaging layer 122 that are sheared to obtain the final three-electrode battery 100.

[0081] Since the first auxiliary electrode 210, the second auxiliary electrode 230, the first auxiliary separator 220 and the second auxiliary separator 240 are only used when adjusting the state of charge of the reference electrode 113 and are not present in the final three-electrode battery 100, 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 performing S310-S360 has the advantage of smaller battery capacity error.

[0082] It should be noted that the manufacturing method provided in the embodiment is not limited to being executed in the order of S310-S360, and the execution order of S340 and S350 can be exchanged, for example, S340 can be executed first, and then S350 can be executed, or S350 can be executed first, and then S340 can be executed, which can all achieve the purpose of adjusting the state of charge of the reference electrode 113 to half-electricity, and is not specifically limited here.

[0083] As shown in FIG. 4, 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 loop is charged and discharged through the external circuit, so that the side of the reference electrode 113 towards the negative electrode sheet 111 is in half-electricity, including the following sub-steps: Figure 6 S341, the first auxiliary electrode 210 is connected 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;

[0084] S342, charge the loop through the battery testing device according to a preset rate until the cut-off voltage;

[0085] S343, obtain the charging capacity of the side of the reference electrode 113 towards the negative electrode sheet 111 through the battery testing device, and then discharge the loop through the battery testing device according to 50% of the charging capacity and a preset rate.

[0086]

[0087] ​It is understood 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 the negative electrode, and the reference electrode 113 is connected to the battery testing device as the positive electrode. S342 is executed to charge the circuit at a preset rate through the battery testing device until the cutoff voltage is reached, so that the first auxiliary electrode 210 continuously plates lithium ions from the reference electrode 113 during the charging process. S343 is executed to obtain the charging capacity of the reference electrode 113 on the side facing the negative electrode sheet 111 through the battery testing device, and then the circuit is discharged through the battery testing device at 50% of the charging capacity and at a preset rate, thereby adjusting the reference electrode 113 on the side facing the negative electrode sheet 111 to a half-charged state.

[0088] It should be noted that the battery testing device described above is used to provide an external circuit for adjusting the state of charge of the reference electrode 113 for the three-electrode battery 100. For example, the preset rate may be 0.05C and the cutoff voltage may be 3.7V. These settings can be made according to design requirements and are not specifically limited herein.

[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 side 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 can be understood that in the manufacturing method of the three-electrode battery 100 provided by the embodiment, the second auxiliary electrode 230 is connected 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 in S351. In S352, the circuit is charged by the battery testing device at a preset rate until the cut-off voltage, so that the second auxiliary electrode 230 continuously plating lithium ions into the reference electrode 113 during the charging process. In S353, the charging capacity of the side of the reference electrode 113 facing the positive electrode sheet 115 is obtained by the battery testing device, and then the circuit is discharged by the battery testing device at 50% of the charging capacity and the preset rate, so as to realize the adjustment of the side of the reference electrode 113 facing the positive electrode sheet 115 to the half-electric state.

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

[0095] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art 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 limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A three-electrode cell, characterized in that, The three-electrode battery has a first direction, a second direction and a third direction perpendicular to each other, and comprises: an electrode assembly comprising, in sequence along a preset direction, a negative electrode sheet, a first separator, a reference electrode, a second separator and a positive electrode sheet, the preset direction being parallel to the third direction; a package comprising a first package layer and a second package layer, edges of the first package layer and edges of the second package layer being connected to form a receiving cavity capable of containing electrolyte, the package containing the electrode assembly through the receiving cavity; when adjusting the state of charge of the reference electrode, the three-electrode battery is connected with a first auxiliary electrode, a second auxiliary electrode, a first auxiliary separator and a second auxiliary separator; the first auxiliary electrode is located on one side of the package along the second direction, the second auxiliary electrode is located on the other side of the package along the second direction, the first auxiliary electrode and the first auxiliary separator are sequentially stacked between the first separator and the reference electrode along the preset direction, the second auxiliary separator and the second auxiliary electrode are sequentially stacked between the reference electrode and the second separator along the preset direction, the first auxiliary electrode and the second auxiliary electrode are connected with a negative electrode of an external circuit, the reference electrode is connected with a positive electrode of the external circuit, the reference electrode comprises an aluminum foil layer and a lithium iron phosphate layer, the aluminum foil layer is partially coated with the lithium iron phosphate layer on both opposite sides along the third direction, the first auxiliary electrode and the second auxiliary electrode each comprise a copper foil layer and a graphite layer, the copper foil layer is partially coated with the graphite layer on both opposite sides along the third direction, the three-electrode battery further has a projection plane, the projection plane is perpendicular to the preset direction, and a normal projection of the graphite layer on the projection plane completely covers a normal projection of the lithium iron phosphate layer on the projection plane.

2. The three-electrode cell of claim 1, wherein, The three-electrode battery further comprises a positive electrode tab and a negative electrode tab, the positive electrode tab and the negative electrode tab 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 tab is connected with the positive electrode sheet, and the negative electrode tab is connected with the negative electrode sheet.

3. The three-electrode cell of claim 1, wherein, The reference electrode is located at an edge of the positive electrode sheet, so that a normal projection of the positive electrode sheet on the projection plane completely covers a normal projection of the lithium iron phosphate layer on the projection plane.

4. The three-electrode cell of claim 1, wherein, The aluminum foil layer and the lithium iron phosphate layer each have a dimension W1 along the second direction, and the positive electrode sheet has a dimension W2 along the second direction, and W1 < 0.05W2 is satisfied.

5. The three-electrode cell of claim 1, wherein, The aluminum foil layer and the lithium iron phosphate layer each have a dimension W1 along the second direction, and the copper foil layer and the graphite layer each have a dimension W3 along the first direction, and W3 > W1 is satisfied.

6. A method of manufacturing a three-electrode battery as claimed in any one of claims 1 to 5, characterized in that, The manufacturing method comprises: obtaining the first package 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 package layer; stacking the first encapsulation 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 encapsulation layer in sequence along the preset direction; connecting edges of the first encapsulation layer and edges of the second encapsulation layer except where the reference electrode is located to form an encapsulation body having a containing cavity, then injecting an electrolyte into the containing cavity through an opening formed by the edges of the first encapsulation layer and the edges of the second encapsulation layer where the reference electrode is located, and then connecting the edges of the first encapsulation layer and the edges of the second encapsulation layer where the reference electrode is located to close the opening; connecting the first auxiliary electrode to a negative electrode of an external circuit and connecting the reference electrode to a positive electrode of the external circuit to form a first loop, and then charging and discharging the first loop through the external circuit to make the reference electrode at a side facing the negative electrode sheet in a semi-electric state; connecting the second auxiliary electrode to a negative electrode of an external circuit and connecting the reference electrode to a positive electrode of the external circuit to form a second loop, and then charging and discharging the second loop through the external circuit to make the reference electrode at a side facing the positive electrode sheet in a semi-electric state; cutting edges of the encapsulation body at where the first auxiliary electrode and the second auxiliary electrode are located, then taking out the first auxiliary electrode, the first auxiliary separator, the second auxiliary electrode and the second auxiliary separator, and then reconnecting the cut edges of the first encapsulation layer and the edges of the second encapsulation layer.

7. The method of claim 6, wherein the method further comprises: The connecting the first auxiliary electrode to a negative electrode of an external circuit and connecting the reference electrode to a positive electrode of the external circuit to form a first loop, and then charging and discharging the first loop through the external circuit to make the reference electrode at a side facing the negative electrode sheet in a semi-electric state, comprises: connecting the first auxiliary electrode to a battery testing device as a negative electrode and connecting the reference electrode to the battery testing device as a positive electrode; charging the first loop through the battery testing device at a preset rate until a cut-off voltage; obtaining a charging capacity of the reference electrode at a side facing the negative electrode sheet through the battery testing device, and then discharging the first loop through the battery testing device at 50% of the charging capacity and the preset rate.

8. The method of claim 6, wherein the method further comprises: The connecting the second auxiliary electrode to a negative electrode of an external circuit and connecting the reference electrode to a positive electrode of the external circuit to form a second loop, and then charging and discharging the second loop through the external circuit to make the reference electrode at a side facing the positive electrode sheet in a semi-electric state, comprises: connecting the second auxiliary electrode to a battery testing device as a negative electrode and connecting the reference electrode to the battery testing device as a positive electrode; charging the second loop through the battery testing device at a preset rate until a cut-off voltage; obtaining a charging capacity of the reference electrode at a side facing the positive electrode sheet through the battery testing device, and then discharging the second loop through the battery testing device at 50% of the charging capacity and the preset rate. The charging capacity of the side of the reference electrode facing the positive electrode sheet is acquired by the battery testing device, and then the second loop is discharged by the battery testing device at 50% of the charging capacity and the preset rate.

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