Bipolar Battery and its Preparation Method

Abstract

This application discloses a bipolar battery and its fabrication method. The bipolar battery includes: multiple current collectors, a positive electrode layer, a negative electrode layer, a separator, an electrolyte, and an encapsulation body. The current collectors, positive electrode layer, separator, and negative electrode layer are sequentially stacked to form multiple battery cells connected in series. The electrolyte at least impregnates the separator. Both the current collectors and the separator extend beyond the positive and negative electrode layers in a direction perpendicular to their stacking direction, forming an encapsulation region on one side of the positive and negative electrode layers. The encapsulation body is disposed within the encapsulation region and is made of a photocurable material. The advantage of this application is that it provides a bipolar battery and its fabrication method that can effectively encapsulate the sides of the bipolar battery through a photocurable effect.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a bipolar battery and its preparation method. Background Technology

[0002] A bipolar battery is a battery in which positive and negative active materials are coated on both sides of a bipolar current collector, and then connected in series with an electrolyte. The bipolar electrode structure makes it easier to achieve high voltage, is more efficient than multiple batteries in series, and minimizes the use of electrochemically inert components such as packaging bags, reducing ineffective mounting space and lowering connection resistance, thus contributing to higher energy density. Because bipolar batteries are connected in series, a "liquid electrolyte + electrode barrier insulation device" is required to prevent ion flow between adjacent cells and voltage accumulation. However, this "liquid electrolyte + electrode barrier insulation device" requires individual sealing of each layer of electrodes after electrolyte injection, which is cumbersome and poses a significant challenge to practical applications. Summary of the Invention

[0003] In view of this, this application provides a light-emitting device aimed at improving the problem of difficult packaging of existing bipolar batteries.

[0004] The embodiments of this application are implemented as follows: a bipolar battery includes:

[0005] Multiple current collectors, positive electrode layer, negative electrode layer, separator, electrolyte, and encapsulation body;

[0006] The current collector, positive electrode layer, separator, and negative electrode layer are stacked sequentially to form multiple battery units connected in series in the bipolar battery.

[0007] The electrolyte at least impregnates the diaphragm;

[0008] The current collector and the separator both extend beyond the positive electrode layer and the negative electrode layer in a direction perpendicular to their stacking direction, so that the current collector and the separator form an encapsulation region on one side of the positive electrode layer and the negative electrode layer;

[0009] The encapsulation body is disposed within the encapsulation area and is made of a light-curing material.

[0010] Optionally, in some embodiments of this application, the number of current collectors ranges from 10 to 300.

[0011] Optionally, in some embodiments of this application, the thickness of the diaphragm is in the range of 10-20 μm.

[0012] Optionally, in some embodiments of this application, the thickness of the positive electrode layer or the negative electrode layer ranges from 30 to 80 μm.

[0013] Optionally, in some embodiments of this application, the depth of the encapsulation region ranges from 80 to 100 μm.

[0014] Optionally, in some embodiments of this application, the encapsulation body of each encapsulation region is made of the same one-piece molded photocurable material.

[0015] Accordingly, embodiments of this application also provide a method for preparing a bipolar battery, comprising:

[0016] It provides multiple current collectors, positive electrode layers, negative electrode layers, separators, electrolytes, and encapsulation bodies;

[0017] The current collector, positive electrode layer, separator, and negative electrode layer are stacked sequentially such that the current collector and separator extend beyond the positive electrode layer and the negative electrode layer in the direction perpendicular to their stacking direction, so that the current collector and the separator form an encapsulation region on one side of the positive electrode layer and the negative electrode layer;

[0018] The electrolyte is used to wet the entire assembly consisting of the current collector, positive electrode layer, separator, and negative electrode layer stacked in sequence.

[0019] The current collector, positive electrode layer, separator, negative electrode layer, and electrolyte, after being impregnated, are subjected to potting treatment so that the uncured photocurable material fills all the encapsulation areas;

[0020] A light source is used to irradiate the photocurable material in the encapsulation area to cure it.

[0021] Optionally, in some embodiments of this application, the maximum unilateral illumination angle α of the light source satisfies in,

[0022] a is the thickness of the positive or negative electrode layer, b is the thickness of the separator, c is the depth of the encapsulation area, d is the shortest distance between the light source and the positive or negative electrode layer, and n is the number of current collectors.

[0023] Optionally, in some embodiments of this application, the maximum unilateral illumination angle α of the light source satisfies

[0024]

[0025] Where a is the thickness of the positive or negative electrode layer, b is the thickness of the separator, c is the depth of the encapsulation area, d is the shortest distance between the light source and the positive or negative electrode layer, and n is the number of current collectors.

[0026] Optionally, in some embodiments of this application, the light source moves along the direction of the current collector, the positive electrode layer, the separator, and the negative electrode layer.

[0027] The advantage of this application is that it provides a bipolar battery that can effectively encapsulate the side of a bipolar battery through the photo-solidification effect, and a method for preparing the same. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a photograph of a bipolar battery provided in an embodiment of this application;

[0030] Figure 2 This is a schematic diagram of the structure of a bipolar battery provided in an embodiment of this application;

[0031] Figure 3 This is a schematic diagram of the main steps of a method for preparing a bipolar battery provided in this application embodiment.

[0032] Meaning of the reference numerals in the diagram:

[0033] 100. Bipolar battery; 102. Positive electrode layer; 103. Negative electrode layer; 104. Separator; 105. Encapsulation space; S. Trajectory of the light source. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0037] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0038] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0039] In this application, the term "on" forming another layer on a certain layer is a broad concept. It can mean that the formed other layer is adjacent to a certain layer, or it can mean that there are other spacer structures between the other layer and the certain layer. For example, when a second electrode is formed "on" a first charge carrier functional layer, the term "on" can mean that the formed second electrode is adjacent to the first charge carrier functional layer, or it can mean that there are other spacer structures between the second electrode and the first charge carrier functional layer, such as a light-emitting layer.

[0040] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0041] The technical solution of this application is as follows:

[0042] Reference Figure 1 and Figure 2 As shown, in a first aspect, embodiments of this application provide a bipolar battery, including: a plurality of battery cells.

[0043] Specifically, a bipolar battery includes: multiple current collectors, a positive electrode layer, a negative electrode layer, a separator, an electrolyte, and a package.

[0044] The current collector, positive electrode layer, separator, and negative electrode layer are stacked sequentially to form multiple battery cells connected in series in the bipolar battery; the electrolyte impregnates at least the separator; the current collector and separator extend beyond the positive electrode layer and the negative electrode layer in a direction perpendicular to their stacking direction so that the current collector and the separator form an encapsulation region on one side of the positive electrode layer and the negative electrode layer; the encapsulation body is disposed within the encapsulation region and is made of a light-cured material.

[0045] In some embodiments of this application, the number of current collectors ranges from 10 to 300. More specifically, a more preferred range is 25 to 175.

[0046] In some embodiments of this application, the thickness of the diaphragm ranges from 10 to 20 μm. More specifically, a more preferred range is 12 to 15 μm.

[0047] Optionally, in some embodiments of this application, the thickness of the positive electrode layer or the negative electrode layer ranges from 30 to 80 μm. More specifically, a more preferred range is 40 to 65 μm.

[0048] In some embodiments of this application, the depth of the encapsulation region ranges from 20 to 1000 μm. More specifically, a more preferred range is 100 to 800 μm.

[0049] In some embodiments of this application, the encapsulation body for each of the encapsulation regions is made of the same one-piece molded photocurable material. More specifically, the photocurable material is preferably an acrylic resin.

[0050] Reference Figure 2 and Figure 3 As shown in the embodiments of this application, a method for preparing a bipolar battery is also provided.

[0051] Specifically, the preparation method includes:

[0052] S101: Provides multiple current collectors, positive electrode layers, negative electrode layers, separators, electrolytes, and encapsulation.

[0053] S102: The current collector, positive electrode layer, separator, and negative electrode layer are stacked sequentially such that the current collector and separator both extend beyond the positive electrode layer and the negative electrode layer in the direction perpendicular to their stacking direction, so that the current collector and the separator form an encapsulation region on one side of the positive electrode layer and the negative electrode layer;

[0054] S103: The electrolyte is used to wet the entire assembly consisting of the current collector, positive electrode layer, separator, and negative electrode layer stacked in sequence.

[0055] S104: The current collector, positive electrode layer, separator, negative electrode layer, and electrolyte, after being impregnated, are subjected to potting treatment so that the uncured photocurable material fills all the encapsulation areas;

[0056] S105: Use a light source to irradiate the photocurable material in the encapsulation area to cure it.

[0057] In some embodiments of this application, the maximum single-sided illumination angle α of the light source satisfies in,

[0058] a is the thickness of the positive or negative electrode layer, b is the thickness of the separator, c is the depth of the encapsulation area, d is the shortest distance between the light source and the positive or negative electrode layer, and n is the number of current collectors.

[0059] In some embodiments of this application, the maximum single-sided illumination angle α of the light source satisfies

[0060]

[0061] Where a is the thickness of the positive or negative electrode layer, b is the thickness of the separator, c is the depth of the encapsulation area, d is the shortest distance between the light source and the positive or negative electrode layer, and n is the number of current collectors.

[0062] As a specific scheme, the specific values ​​are a = 50 μm; b = 15 μm; c = 100 μm; d = 1-20 cm; n = 10-300.

[0063] In some embodiments of this application, the light source moves along the direction of the current collector, the positive electrode layer, the separator, and the negative electrode layer. Specifically, the light source is a UV LED light source (wavelength range of 340-420nm); its light intensity ranges from 50-4000mW / cm². 2 The preferred value is 500-2500mW / cm². 2 .

[0064] Compared to insulating components such as electrode gaskets and sealing rings, the above solution not only solves the cumbersome process of single-layer liquid injection and single-layer sealing, improving the efficiency of the packaging process, but also reduces the overall system cost and better meets the comprehensive needs of practical applications.

[0065] As a practical application, a battery cell can be obtained by stacking bipolar electrodes, single-sided positive electrodes, single-sided negative electrodes, and separators in an electrode-separator-electrode sequence. The battery cell is then immersed in an electrolyte solution to achieve complete immersion. The battery cell is then removed and pressurized to remove excess electrolyte solution between layers. The pressurized battery cell is then placed in a polymer potting solution, ensuring that the interlayer of the current collector is fully filled with the potting solution without over-wetting the active material layers. After being irradiated with ultraviolet light, the interlayer of the electrode and current collector is wrapped with a cross-linked polymer film. Finally, the battery cell undergoes encapsulation, formation, and aging processes to obtain a bipolar polymer lithium-ion battery.

[0066] The bipolar battery and its preparation method provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A bipolar battery, characterized in that: the bipolar battery comprises: a plurality of current collectors, positive electrode layers, negative electrode layers, separators, electrolytes, encapsulants; wherein the current collectors, positive electrode layers, separators, and negative electrode layers are sequentially stacked to form a plurality of series-connected battery units; the electrolyte at least impregnates the separators; the current collectors and separators each extend beyond the positive electrode layers and the negative electrode layers in a direction perpendicular to the stacking direction of the current collectors and separators to form an encapsulation region on one side of the positive electrode layers and the negative electrode layers; the encapsulants are disposed in the encapsulation regions and are made of light-curing materials; the electrolyte impregnates the entire structure formed by the sequentially stacked current collectors, positive electrode layers, separators, and negative electrode layers; the entire structure formed by the impregnated current collectors, positive electrode layers, separators, negative electrode layers, and electrolytes is subjected to a glue-filling process to fill all the encapsulation regions with uncured light-curing materials; a light source is used to irradiate the light-curing materials in the encapsulation regions to cure them; The maximum single-side irradiation angle a of the light source satisfies a = 90° - a0 ; wherein, a is the thickness of the positive electrode layers or the negative electrode layers, b is the thickness of the separators, c is the depth of the encapsulation regions, d is the shortest distance from the light source to the positive electrode layers or the negative electrode layers, and n is the number of current collectors. 2.The bipolar battery of claim 1, characterized in that: the number of current collectors ranges from 10 to 300. 3.The bipolar battery of claim 1, characterized in that: the thickness of the separators ranges from 10 to 20 μm. 4.The bipolar battery of claim 1, characterized in that: the thickness of the positive electrode layers or the negative electrode layers ranges from 30 to 80 μm. 5.The bipolar battery of claim 1, characterized in that: the depth of the encapsulation regions ranges from 80 to 100 μm. 6.The bipolar battery of claim 1, characterized in that: the encapsulants of each encapsulation region are made of light-curing materials formed in the same molding process. 7.A method for preparing a bipolar battery, characterized in that: the method comprises: providing a plurality of current collectors, positive electrode layers, negative electrode layers, separators, electrolytes, and encapsulants; sequentially stacking the current collectors, positive electrode layers, separators, and negative electrode layers to form a plurality of series-connected battery units, wherein the current collectors and separators each extend beyond the positive electrode layers and the negative electrode layers in a direction perpendicular to the stacking direction of the current collectors and separators to form an encapsulation region on one side of the positive electrode layers and the negative electrode layers; impregnating the entire structure formed by the sequentially stacked current collectors, positive electrode layers, separators, and negative electrode layers with the electrolyte; subjecting the entire structure formed by the impregnated current collectors, positive electrode layers, separators, negative electrode layers, and electrolytes to a glue-filling process to fill all the encapsulation regions with uncured light-curing materials; irradiating the light-curing materials in the encapsulation regions with a light source to cure them; The maximum single-side irradiation angle a of the light source satisfies a = 90° - a0, wherein a0 is the maximum single-side irradiation angle of the light source in the absence of the light guide plate. ; a is the thickness of the positive or negative electrode layer, b is the thickness of the separator, c is the depth of the encapsulation region; d is the shortest distance of the light source from the positive or negative electrode layer; n is the number of current collectors.

8. The method of claim 7, wherein: the light source moves along the direction of the current collector, positive electrode layer, separator, negative electrode layer.

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