Winding type sodium ion battery cell and battery

Abstract

The utility model provides a coiled sodium ion cell and a battery, which belong to the technical field of batteries, and comprise: a common current collector which is distributed in a coiled shape and forms an isolation space, two ends of the common current collector respectively extend to form a first pole end and a second pole end, the first pole end is inclined inwards, and the second pole end is inclined outwards; one surface of the common current collector is coated with the first active material layer; the second active material layer is coated on the other surface of the common current collector; and an isolating membrane. The winding type battery cell has the beneficial effects that the two ends of the common current collector respectively extend to form the first pole end which is inclined inwards and the second pole end which is inclined outwards, and the first active material layer and the second active material layer are respectively connected from the two ends to form the winding type battery cell, so that the two ends of the winding type battery cell are fully utilized.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries and relates to a wound sodium ion battery cell and a battery. Background Art

[0002] Sodium-ion batteries (Na-ion batteries) are an important energy storage technology with high energy density and good cycle life. However, Na-ion batteries still face some challenges in the selection of anode materials and battery structure.

[0003] Sodium-ion batteries are mainly composed of positive electrode sheets, negative electrode sheets, separators, electrolytes, and shells; the positive electrode sheets are mainly composed of a mixed slurry of (positive electrode active material-conductive agent-binder-solvent), which is coated on a carrier metal aluminum foil, and the coated material is rolled and cut to complete the positive electrode sheets required for the battery; the negative electrode sheets are mainly composed of a mixed slurry of (negative electrode active material-conductive agent-binder-solvent), which is coated on a carrier metal copper foil, carbon-coated aluminum foil, or metal aluminum foil, and the coated material is rolled and cut to complete the negative electrode sheets required for the battery.

[0004] For example, a utility model patent with application number CN202323210442.2 provides a wound sodium-ion battery cell and a battery, which belongs to the field of battery technology, including: a common current collector, which is distributed in a wound shape and forms an isolation space; a first active material layer, which is coated on one side of the common current collector; a second active material layer, which is coated on the other side of the common current collector; an isolation membrane, which is distributed in a wound shape and is located in the isolation space, and the isolation membrane separates the first active material layer and the second active material layer on the inner and outer sides of the common current collector.

[0005] To sum up, in some existing technical solutions, both pole ears are located at one end of the wound sodium ion battery cell. In order to separate the two pole ears, it is necessary to ensure that the space at this end of the wound sodium ion battery cell needs to be reserved. At the same time, the space at the other end of the wound sodium ion battery cell is not fully utilized, and there is a large room for improvement. Summary of the Invention

[0006] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a wound sodium ion battery cell and a battery.

[0007] The purpose of the utility model can be achieved by the following technical solutions: A wound sodium ion battery cell, comprising:

[0008] A common current collector is arranged in a coiled shape and forms an isolation space, wherein two ends of the common current collector extend to form a first extreme point and a second extreme point, respectively, wherein the first extreme point is inclined inwardly and the second extreme point is inclined outwardly;

[0009] a first active material layer, coated on one side of the common current collector;

[0010] a second active material layer coated on the other side of the common current collector;

[0011] The isolation film is distributed in a winding shape and is located in the isolation space. The isolation film separates the first active material layer and the second active material layer on the inner and outer sides of the common current collector.

[0012] In the above-mentioned wound sodium-ion battery cell, the first terminal is coated with the first active material layer, and the side of the first terminal coated with the first active material layer is exposed.

[0013] In the above-mentioned wound sodium-ion battery cell, the second terminal is coated with the second active material layer, and the side of the second terminal coated with the second active material layer is exposed.

[0014] In the above-mentioned wound sodium ion battery cell, the first active material layer is one of the positive electrode active material layer and the negative electrode active material layer, and the second active material layer is the other of the positive electrode active material layer and the negative electrode active material layer.

[0015] In the above-mentioned wound sodium ion battery cell, the common current collector includes a polymer substrate and two aluminum coatings, the two aluminum coatings are respectively arranged on the two sides of the polymer substrate, the first active material layer is arranged on one of the aluminum coatings, and the second active material layer is arranged on the other of the aluminum coatings.

[0016] In the above-mentioned wound sodium ion battery cell, the polymer substrate is a polypropylene member, a polyethylene member, or a polyethylene terephthalate member.

[0017] Secondly, a battery includes the wound sodium ion battery cell, and further includes: a shell, the shell covers the common current collector and the isolation membrane.

[0018] The above-mentioned battery further includes a first cover plate and a second cover plate. The first cover plate covers one end of the shell and contacts the first terminal. The second cover plate covers one end of the shell and contacts the second terminal.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. A first active material layer and a second active material layer are respectively coated on both sides of a common current collector to form two poles, respectively. The two ends of the common current collector extend to form a first extreme point inclined inward and a second extreme point inclined outward. The first active material layer and the second active material layer are respectively connected from both ends to form the wound sodium ion battery cell, thereby fully utilizing the two ends of the wound sodium ion battery cell.

[0021] 2. The first pole is coated with the first active material layer and one side of the first pole coated with the first active material layer is exposed. Therefore, the exposed first active material layer on the first pole can be directly used as a tab of corresponding polarity without the need for additional tab blocks.

[0022] 3. The second pole is coated with a second active material layer and one side of the second pole coated with the second active material layer is exposed. Therefore, the second active material layer exposed on the second pole can be directly used as a tab of corresponding polarity without the need for an additional tab block. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the internal structure of the wound sodium ion battery cell of the present invention.

[0024] Figure 2 for Figure 1 Magnified view of part A.

[0025] Figure 3 for Figure 1 Enlarged view of part B.

[0026] Figure 4 This is an exploded view of the battery of the present invention.

[0027] In the figure, 100 is a common current collector; 110 is a first pole; 120 is a second pole; 200 is a first active material layer; 300 is a second active material layer; 400 is an isolation membrane; 500 is a housing; 600 is a first cover plate; and 700 is a second cover plate. DETAILED DESCRIPTION

[0028] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0029] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] In addition, terms such as "first," "second," and "an" in this utility model are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0031] In this utility model, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0032] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0033] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

[0034] like Figure 1-Figure 3 As shown, a wound sodium ion battery cell includes: a common current collector, a first active material layer, a second active material layer and an isolation membrane.

[0035] The common current collector is distributed in a winding shape and forms an isolation space. Two ends of the common current collector extend to form a first extreme point and a second extreme point, respectively. The first extreme point is inclined inward, and the second extreme point is inclined outward.

[0036] Wherein, the first active material layer is coated on one side of the common current collector.

[0037] Specifically, the first active material layer is one of a positive electrode active material layer and a negative electrode active material layer.

[0038] Wherein, the second active material layer is coated on the other side of the common current collector.

[0039] Specifically, the second active material layer is the other of the positive electrode active material layer and the negative electrode active material layer.

[0040] The isolation film is distributed in a winding shape and is located in the isolation space. The isolation film separates the first active material layer and the second active material layer on the inner and outer sides of the common current collector.

[0041] In addition, the isolation membrane is resistant to high temperatures, further enhancing the safety performance of the battery.

[0042] In this embodiment, the first active material layer and the second active material layer are respectively coated on both sides of the common current collector to form two poles, respectively. The two ends of the common current collector extend to form a first extreme point inclined inward and a second extreme point inclined outward. The first active material layer and the second active material layer are respectively connected from the two ends to form the wound sodium ion battery cell, thereby fully utilizing the two ends of the wound sodium ion battery cell.

[0043] like Figure 1-Figure 3 As shown, based on the above embodiment, the first pole end is coated with the first active material layer, and the side of the first pole end coated with the first active material layer is exposed.

[0044] In this embodiment, the first pole is coated with a first active material layer and one side of the first pole coated with the first active material layer is exposed. Therefore, the exposed first active material layer on the first pole can be directly used as a tab of corresponding polarity without the need for an additional tab block.

[0045] like Figure 1-Figure 3 As shown, based on the above embodiment, the second pole terminal is coated with the second active material layer, and the side of the second pole terminal coated with the second active material layer is exposed.

[0046] In this embodiment, the second pole is coated with a second active material layer and one side of the second pole coated with the second active material layer is exposed. Therefore, the exposed second active material layer on the second pole can be directly used as a tab of corresponding polarity without the need for an additional tab block.

[0047] like Figure 1-Figure 3 As shown, based on the above embodiment, the common current collector includes a polymer substrate (not shown in the figure) and two aluminum coatings (not shown in the figure), the two aluminum coatings are respectively arranged on the two sides of the polymer substrate, the first active material layer is arranged on one of the aluminum coatings, and the second active material layer is arranged on the other of the aluminum coatings.

[0048] It is worth mentioning here that in the prior art, although cheap aluminum foil can be used as the negative electrode coating carrier of sodium ion batteries and it will not produce alloy reaction with sodium, various problems will occur when pure electrolytic aluminum foil is used as the negative electrode current collector of sodium battery. Since the aluminum foil surface is relatively "smooth" and the tension generated by the negative electrode slurry is too small, it will cause "shrinkage (slurry shrinkage)" and foil leakage during coating, which is difficult to process. If carbon-coated aluminum foil is used and the material cost is high, new directions will be adopted for negative electrode current collection on aluminum foil when sodium ion batteries are manufactured. For example, the formula of the slurry is mainly to increase the adhesion to make up for the material disadvantages.

[0049] Therefore, the current choice of copper foil for sodium-ion battery anodes is too costly, and the use of electrolytic aluminum foil as the current collector for sodium-ion battery anodes presents various coating problems. Furthermore, the energy density and safety of existing sodium-ion batteries, due to their imperfect structure, still need further improvement.

[0050] In this embodiment, the polymer substrate of the shared current collector provides insulation, making the first active material layer and the second active material layer incompatible with each other and able to exist independently. The shared current collector can reduce the space used by the original two current collectors and increase the energy density of the sodium ion battery by more than 10%.

[0051] At the same time, the common current collector formed by the two aluminum coatings respectively arranged on the two sides of the polymer substrate has high electrical conductivity and chemical stability, can achieve higher energy storage efficiency, and enable the sodium ion battery to have higher energy storage capacity in a limited space.

[0052] It is also worth mentioning here that compared with the existing technology, the positive and negative electrodes require aluminum foil layers and copper foil layers respectively, which reduces the cost of using the current collector, and uses aluminum foil layers instead of copper foil layers in the negative electrode, which greatly reduces the cost and weight of the negative electrode current collector.

[0053] like Figure 1-Figure 3 As shown, based on the above embodiment, the polymer substrate is a polypropylene piece, a polyethylene piece, or a polyethylene terephthalate piece.

[0054] In this embodiment, the polymer substrate is a polypropylene member, a polyethylene member, or a polyethylene terephthalate member. The insulation of the polymer substrate improves battery safety, reduces independent negative electrode current collectors, and greatly improves production efficiency during coating.

[0055] Specifically, polypropylene or polyethylene parts have good insulation properties, which can effectively isolate the positive and negative electrodes in the battery, reduce the risk of short circuits, and are crucial to improving battery safety; polypropylene or polyethylene parts have high chemical stability and can withstand chemical reactions inside the battery and corrosion from the electrolyte. This helps to extend the service life and stability of the battery; polypropylene or polyethylene parts have good mechanical strength and toughness, and can provide the physical support required for battery components. They have high tear and impact resistance and can maintain structural integrity during battery assembly and use; polypropylene or polyethylene parts are common plastic materials with low cost and wide supply, which reduces the cost of sodium-ion battery manufacturing and increases feasibility and sustainability.

[0056] like Figure 1-Figure 4 As shown, a battery includes the wound sodium ion battery cell described above, and further includes: a shell, the shell covering the common current collector and the isolation membrane.

[0057] In this embodiment, the battery cell is assembled into a casing, and the electrolyte is injected and packaged to ensure the sealing of the battery.

[0058] like Figure 1-Figure 4 As shown, based on the above embodiment, it further includes a first cover plate and a second cover plate, the first cover plate covers one end of the shell and contacts the first extreme end, and the second cover plate covers one end of the shell and contacts the second extreme end.

Claims

1. A wound sodium ion battery cell, characterized in that: include: A common current collector is arranged in a coiled shape and forms an isolation space, wherein two ends of the common current collector extend to form a first extreme point and a second extreme point, respectively, wherein the first extreme point is inclined inwardly and the second extreme point is inclined outwardly; a first active material layer, coated on one side of the common current collector; a second active material layer coated on the other side of the common current collector; The isolation film is distributed in a winding shape and is located in the isolation space. The isolation film separates the first active material layer and the second active material layer on the inner and outer sides of the common current collector.

2. A wound sodium ion battery cell according to claim 1, characterized in that: The first pole terminal is coated with the first active material layer, and a side of the first pole terminal coated with the first active material layer is exposed.

3. The wound sodium ion battery cell according to claim 1, wherein: The second active material layer is coated on the second terminal end, and a surface of the second terminal end coated with the second active material layer is exposed.

4. The wound sodium ion battery cell according to claim 1, wherein: The first active material layer is one of the positive electrode active material layer and the negative electrode active material layer, and the second active material layer is the other of the positive electrode active material layer and the negative electrode active material layer.

5. The wound sodium ion battery cell according to claim 1, wherein: The common current collector includes a polymer substrate and two aluminum coatings, wherein the two aluminum coatings are respectively arranged on two sides of the polymer substrate, the first active material layer is arranged on one of the aluminum coatings, and the second active material layer is arranged on the other of the aluminum coatings.

6. A wound sodium ion battery cell according to claim 5, characterized in that: The polymer substrate is a polypropylene member, a polyethylene member, or a polyethylene terephthalate member.

7. A battery, characterized in that: The invention comprises a wound sodium ion battery cell according to any one of claims 1 to 6, further comprising: a shell, wherein the shell covers the common current collector and the isolation membrane.

8. A battery according to claim 7, characterized in that: The first cover plate covers one end of the housing and contacts the first pole, and the second cover plate covers one end of the housing and contacts the second pole.

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