Battery cell pole piece structure, winding battery cell and battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell pole piece structure, a winding battery cell and a battery. The battery cell pole piece structure comprises a current collector, and the current collector is provided with a double-sided area and a single-sided area which are arranged in sequence; first active material layers and second active material layers, wherein the first active material layers are arranged on two side surfaces of the double-sided region in the current collector; the second active material layer is arranged on the surface of one side of the single-sided region in the current collector; a clearance groove is formed in the junction of the first active material layer and the second active material layer; and the buffer component is connected to the interior of the clearance groove. According to the utility model, after being extruded by the expansive force of the pole piece, the pole piece is firstly compressed, so that the expansive force of each layer of pole piece is prevented from being accumulated outwards at the corner of the single-face and double-face junction of the pole piece to cause breakage at the corner; therefore, the stability of the structure can be improved, and the use safety and stability are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field, and in particular relates to a battery cell pole piece structure, a wound battery cell and a battery. Background Art

[0002] Lithium-ion batteries are composed of components such as the positive electrode, negative electrode, separator, and electrolyte. Cell production is completed through processes such as homogenization, coating, rolling, slitting, winding, injection, assembly, and formation. Increasing the energy density of the cell can be achieved by adjusting the gram capacity and thickness of each component material. For the positive electrode, energy density requirements can be met by introducing high-gram capacity positive electrode materials, increasing the positive electrode's areal density, and improving positive electrode compaction. It should be noted that lithium-ion batteries are divided into hard-shell batteries and soft-pack batteries.

[0003] However, as battery cell energy density continues to increase, the electrode compaction density increases while the foil becomes thinner. During roller pressing, a thickness difference occurs from double-sided to single-sided, and the aluminum foil strength at the junction of the single and double-sided surfaces becomes the weakest point in the cathode sheet. When the battery cell cycles, the expansion force of the anode and cathode is transmitted outward. If this expansion force is too great, it can cause fractures at the junction of the cathode and double-sided surfaces, thereby reducing structural stability, safety, and capacity, affecting the user experience. Utility Model Content

[0004] The purpose of the present invention is to provide a battery cell pole piece structure, a wound battery cell and a battery in response to the deficiencies in the prior art, which can solve the technical problem of poor structural stability of the prior art.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A battery cell electrode structure, comprising:

[0007] A current collector, wherein the current collector is provided with a double-sided area and a single-sided area arranged in sequence;

[0008] a first active material layer and a second active material layer, wherein the first active material layer is disposed on both sides of the double-sided region of the current collector; the second active material layer is disposed on one side of the single-sided region of the current collector; and a gas-proof groove is provided at the junction of the first active material layer and the second active material layer;

[0009] A buffer component is connected to the interior of the air-avoiding groove.

[0010] Preferably, the buffer component is provided at a corner section of the battery cell where the current collector is located.

[0011] Preferably, the buffer component includes an adhesive layer and a foam layer stacked in sequence; the adhesive layer is connected to the inner bottom of the air-avoiding groove; and the foam layer is extended toward the opening of the air-avoiding groove.

[0012] Preferably, the adhesive layer is made of one of acrylic resin, polycarbonate, polyurethane and rubber.

[0013] Preferably, the relationship between the width L1 of the buffer component and the width L2 of the current collector satisfies: L1 ≥ L2.

[0014] Preferably, the relationship between the length W2 of the air-avoiding groove and the length W1 of the buffer component satisfies: W2 = W1.

[0015] Preferably, the thickness D1 of the buffer component satisfies: 50 μm≤D1≤300 μm.

[0016] The present utility model also discloses a wound battery cell, comprising a first pole piece, an isolation membrane, and a second pole piece arranged in sequence; the polarity of the first pole piece is opposite to the polarity of the second pole piece; the first pole piece, the isolation membrane, and the second pole piece are stacked in sequence and wound to form a winding body; and the air-avoiding groove is arranged at the corner section of the winding body; the first pole piece and / or the second pole piece is the battery cell pole piece structure described above.

[0017] Preferably, the relationship between the length W2 of the air-avoiding groove and the thickness H of the wound body satisfies: 3mm≤W2≤π*H.

[0018] The utility model also discloses a battery, comprising the wound battery core.

[0019] The beneficial effect of the present invention is that the technical solution reserves air-avoiding grooves with air-avoiding positions in the double-sided area and the single-sided area in the long membrane surface of the battery cell electrode structure, and adds a buffer component in the air-avoiding groove, so that the buffering function of the air-avoiding position where the buffer component is located can be played, so that it is first compressed after being squeezed by the expansion force of the electrode, avoiding the expansion force of each layer of the electrode from accumulating outward at the corner of the single-sided and double-sided intersection of the electrode, causing fracture there; thereby, the stability of the structure can be improved, and the safety and stability of use can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following will refer to the attached Figures 1 to 4 To describe the features, advantages and technical effects of exemplary embodiments of the present invention.

[0021] Figure 1 This is a front view of the battery cell electrode structure of an embodiment of the present utility model;

[0022] Figure 2This is a side view of a battery cell electrode structure according to an embodiment of the present invention;

[0023] Figure 3 This is a side view of a battery cell electrode structure according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic structural diagram of a wound battery cell according to an embodiment of the present invention.

[0025] In the figure: 1-current collector; 11-double-sided area; 12-single-sided area; 13-air-avoiding groove; 14-buffer component; 141-adhesive layer; 142-foaming rubber layer; 15-blank area; 2-first active material layer; 3-second active material layer; 5-first adhesive; 6-second adhesive; 100-first pole piece; 200-second pole piece; 300-isolating film; 401-ending section; 402-turning section; 403-straight section; 404-starting section. DETAILED DESCRIPTION

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0027] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0028] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or multiple situations exist. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0030] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0031] The following is combined with Figures 1 to 4 The present invention is further described in detail, but is not intended to limit the present invention.

[0032] like Figure 1 As shown, in one embodiment of the present invention, the battery cell electrode structure includes:

[0033] A current collector 1, wherein the current collector 1 is provided with a double-sided area 11 and a single-sided area 12 arranged in sequence;

[0034] A first active material layer 2 and a second active material layer 3, wherein the first active material layer 2 is disposed on both sides of the double-sided area 11 of the current collector 1; the second active material layer 3 is disposed on one side of the single-sided area 12 of the current collector 1; and a clearance groove 13 is provided at the junction of the first active material layer 2 and the second active material layer 3;

[0035] The buffer component 14 is connected to the interior of the air-avoiding groove 13 .

[0036] The technical solution of the present invention reserves air-avoiding grooves with air-avoiding positions in the double-sided area and the single-sided area in the long film surface of the battery cell electrode structure, and adds a buffer component in the air-avoiding groove, so that the buffer function of the air-avoiding position where the buffer component is located can be played, so that it is first compressed after being squeezed by the expansion force of the electrode, avoiding that the expansion force of each layer of the electrode is all accumulated outward at the corner of the single-sided and double-sided intersection of the electrode, causing fracture at that location; thereby, the stability of the structure can be improved, and the safety and stability of use can be improved.

[0037] The air-avoiding grooves 13 can be manufactured by using intermittent coating during coating, or by removing the active material at the air-avoiding position by laser etching after coating and before rolling.

[0038] The first active material layer 2 and the second active material layer 3 are both made of the same active material. When the current collector 1 is a positive electrode current collector, the first active material layer 2 and the second active material layer 3 are both made of lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. When the current collector 1 is a negative electrode current collector, the first active material layer 2 and the second active material layer 3 are both made of carbon or silicon.

[0039] Among them, such as Figure 1 and 2 As shown, the current collector 1 further includes a blank area 15 ; the double-sided area 11 , the single-sided area 12 , and the blank area 15 are sequentially arranged along the coating direction of the current collector 1 .

[0040] Specifically, in some embodiments, Figure 1 and 4 As shown, the buffer component 14 is provided at the corner section 402 of the cell where the current collector 1 is located. In other words, due to excessive accumulation of expansion force at the corner section 402, it is necessary to add an air-avoiding groove and a buffer component 14 at the location of the corner section 402 to prevent the risk of fracture of the electrode sheet (which can be a cathode sheet or an anode sheet, preferably a cathode sheet) on one or both sides due to the accumulation of expansion force.

[0041] Specifically, in some embodiments, Figure 1 and 2 As shown, the buffer component 14 includes an adhesive layer 141 and a foam layer 142 stacked in sequence; the adhesive layer 141 is connected to the inner bottom of the air-avoiding groove 13; and the foam layer 142 extends toward the opening of the air-avoiding groove 13. In other words, the adhesive layer 141 provides assembly stability to ensure the installation stability of the buffer component 14. Furthermore, the foam layer 142 has a high porosity and softness, so that it is first compressed after being squeezed by the expansion force of the electrode, preventing the expansion force of each layer of the electrode from accumulating outward at the corner where the single-sided and double-sided intersection of the electrode sheet causes fracture. This improves the stability of the structure and enhances the safety and stability of use. Furthermore, the foam layer, with its large number of voids, can increase the electrolyte storage capacity of the battery cell, thereby improving the efficiency of the battery cell. In some embodiments, the adhesive layer 141 can be made of one of acrylic resin, polycarbonate, polyurethane, and rubber. This structure further ensures the installation stability of the buffer component 14. The relationship between the thickness D3 of the adhesive layer 141 and the thickness D4 of the foam layer 142 satisfies the following equation: D3<D4. This structure can ensure the thickness of the buffer stress while ensuring the electrolyte storage capacity of the battery cell.

[0042] Specifically, in some embodiments, Figure 1 and 2As shown, the relationship between the width L1 of the buffer component 14 and the width L2 of the current collector 1 satisfies the following: L1 ≥ L2. This structure, through the relatively long buffer component 14, can achieve a buffering effect on all parts of the current collector 1 at that location, thereby further preventing the expansion force of each layer of the electrode from accumulating outward at the corner where the single-sided and double-sided intersection of the electrode sheet may cause fracture at that location; thereby improving the stability of the structure and enhancing the safety and stability of use.

[0043] Specifically, in some embodiments, Figure 1 and 2 As shown, the relationship between the length W2 of the air-avoidance groove 13 and the length W1 of the buffer component 14 satisfies: W2 = W1. This structure uses the buffer component 14 to completely cover the interior of the air-avoidance groove 13 to achieve the largest possible buffer coverage area, thereby further preventing the expansion force of each layer of the electrode from accumulating outward at the corner where the single-sided and double-sided intersection of the electrode piece may cause fracture there; thereby improving the stability of the structure and enhancing the safety and stability of use.

[0044] Specifically, in some embodiments, Figure 1 and 2 As shown, the thickness D1 of the buffer component 14 satisfies the following conditions: 50μm≤D1≤300μm. This structure, through the rationally designed buffer component 14, can further prevent the expansion force of each layer of the electrode from accumulating outward at the corner where the single-sided and double-sided interfaces of the electrode can intersect, causing fractures there; thereby improving the stability of the structure and enhancing safety and stability in use.

[0045] The relationship between the thickness D1 of the buffer component 14 and the thickness D2 of the first active material layer 2 or the second active material layer 3 satisfies: D1≤D2. This structure can ensure the flatness of the entire electrode structure, thereby ensuring its structural stability.

[0046] Specifically, in some embodiments, Figure 2 and 3As shown, the cell electrode structure also includes a first adhesive 5 and a second adhesive 6; the first adhesive 5 is arranged in the single-sided area 12; and one side surface of the first adhesive 5 is respectively connected to the surface of the current collector 1 in the single-sided area 12 and the second active material layer 3; the second adhesive 6 is arranged in the double-sided area 11; and one side surface of the second adhesive 6 is respectively connected to the surface of the current collector 1 in the double-sided area 11 and the first active material layer 2; wherein, the first adhesive 5 is a first green glue; the second adhesive 6 is a second green glue. Furthermore, the length of the second adhesive 6 (second green glue) is greater than the length W1 of the buffer component 14. This structure realizes the filling and protection function of the current collector 1 in the single-sided area 12 through the first adhesive 5, and then the filling and protection function of the current collector 1 in the double-sided area 11 through the second adhesive 6; thereby, the stability of the overall structure can be improved and the safety of use can be guaranteed.

[0047] The present invention also provides a wound battery cell, such as Figure 4 As shown, the wound battery cell includes a first pole piece 100, an isolation film 300 and a second pole piece 200 arranged in sequence; the polarity of the first pole piece 100 is opposite to that of the second pole piece 200; the first pole piece 100, the isolation film 300 and the second pole piece 200 are stacked in sequence and wound to form a winding body; the winding body includes a tail section 401, a starting section 404, at least two corner sections 402 and at least two straight sections 403; one end of the starting section 404 is connected to one end of one of the corner sections 402; the other end of one of the corner sections 402 is connected to one end of one of the straight sections 403; the other end of one of the straight sections 403 is connected to one end of the other corner section 402; and the other end of the straight section 403 is connected to one end of the other corner section 402. The other end of the corner section 402 is connected to one end of the other straight section 403; the other end of the other straight section 403 is connected to one end of the tail section 401; and the air-avoiding groove 13 is provided at the corner section 402 in the first pole piece 100; and / or, the air-avoiding groove 13 is provided at the corner section 402 in the second pole piece 200; the first pole piece 100 and / or the second pole piece 200 is a cell pole piece structure; the specific structure of the cell pole piece structure refers to the above embodiment, and since the present wound cell adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here. Among them, in some embodiments, such as Figure 4 As shown, the first electrode 100 is a negative electrode; the second electrode 200 is a positive electrode.

[0048] Specifically, in some embodiments, Figure 2 and 4As shown, the relationship between the length W2 of the avoidance groove 13 and the thickness H of the wound body satisfies the following equation: 3mm≤W2≤π*H; specifically, 3mm≤W2=π*H / 2. This means that by properly configuring the avoidance groove 13, the foam layer 142 located at the corner section 402, due to its high porosity and flexibility, is compressed first after being squeezed by the electrode expansion force during the battery cell cycle. This prevents the expansion force of each electrode layer from accumulating outward at the corner where the cathode's single and double surfaces meet, causing fracture there.

[0049] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, which is coated on the surface of the positive electrode current collector. The positive electrode current collector includes a positive electrode coating region and a positive electrode tab connected to the positive electrode coating region. The positive electrode coating region is coated with the positive electrode active material layer, while the positive electrode tab is not coated with the positive electrode active material layer. The positive electrode current collector can be made of aluminum, and the positive electrode active material layer includes a positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, which is coated on the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode coating region and a negative electrode tab connected to the negative electrode coating region. The negative electrode coating region is coated with the negative electrode active material layer, while the negative electrode tab is not coated with the negative electrode active material layer. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes a negative electrode active material, which can be carbon or silicon, etc. The material of the isolation film 300 can be PP (polypropylene) or PE (polyethylene).

[0050] The present invention also proposes a battery, which includes a wound battery cell. The specific structure of the wound battery cell refers to the above-mentioned embodiment. Since this battery adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0051] A battery refers to a cup, tank, or other container, or a portion of a composite container, that contains an electrolyte solution and metal electrodes to generate an electric current. It is a device capable of converting chemical energy into electrical energy. Batteries have positive and negative electrodes. With technological advancements, batteries have become a general term for small devices that can generate electrical energy, such as solar cells. Key battery performance parameters include electromotive force, capacity, specific energy, and resistance. Battery Principle: In chemical batteries, the direct conversion of chemical energy into electrical energy occurs through spontaneous chemical reactions within the battery, such as oxidation and reduction, which occur at the two electrodes. The negative electrode active material consists of a reducing agent with a relatively negative potential and is stable in the electrolyte, such as active metals like zinc, cadmium, and lead, and hydrogen or hydrocarbons. The positive electrode active material consists of an oxidizing agent with a relatively positive potential and is stable in the electrolyte, such as metal oxides like manganese dioxide, lead dioxide, and nickel oxide, oxygen or air, halogens and their salts, and oxygen-containing acids and their salts. The electrolyte is a material with good ionic conductivity, such as aqueous solutions of acids, bases, and salts, organic or inorganic non-aqueous solutions, molten salts, or solid electrolytes.

[0052] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0053] Based on the disclosure and teachings of the above description, those skilled in the art will be able to make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above. Any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present invention fall within the scope of protection of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience only and do not constitute any limitation on the present invention.

Claims

1. A battery cell electrode structure, characterized by: include: A current collector, wherein the current collector is provided with a double-sided area and a single-sided area arranged in sequence; a first active material layer and a second active material layer, wherein the first active material layer is disposed on both sides of the double-sided region of the current collector; the second active material layer is disposed on one side of the single-sided region of the current collector; and a gas-proof groove is provided at the junction of the first active material layer and the second active material layer; A buffer component is connected to the interior of the air-avoiding groove.

2. The battery cell electrode structure according to claim 1, characterized in that: The buffer component is arranged at a corner section of the battery cell where the current collector is located.

3. The battery cell electrode structure according to claim 1 or 2, characterized in that: The buffer component includes an adhesive layer and a foam layer stacked in sequence; the adhesive layer is connected to the inner bottom of the air-avoiding groove; and the foam layer is extended toward the opening of the air-avoiding groove.

4. The battery cell electrode structure according to claim 3, characterized in that: The adhesive layer is one of acrylic resin, polycarbonate, polyurethane and rubber.

5. The battery cell electrode structure according to claim 1 or 2, characterized in that: The relationship between the width L1 of the buffer component and the width L2 of the current collector satisfies: L1 ≥ L2.

6. The battery cell electrode structure according to claim 1 or 2, characterized in that: The relationship between the length W2 of the air-avoiding groove and the length W1 of the buffer component satisfies: W2 = W1.

7. The battery cell electrode structure according to claim 1 or 2, characterized in that: The thickness D1 of the buffer component satisfies: 50 μm≤D1≤300 μm.

8. A wound battery cell, characterized in that: It includes a first pole piece, an isolation membrane and a second pole piece arranged in sequence; the polarity of the first pole piece is opposite to the polarity of the second pole piece; the first pole piece, the isolation membrane and the second pole piece are stacked in sequence and wound to form a winding body; and the air avoidance groove is arranged at the corner section of the winding body; the first pole piece and / or the second pole piece is the battery cell pole piece structure as described in any one of claims 1 to 7 above.

9. The wound battery cell according to claim 8, characterized in that: The relationship between the length W2 of the air-avoiding groove and the thickness H of the wound body satisfies: 3mm≤W2≤π*H.

10. A battery, characterized in that: Including the wound battery cell according to claim 8 or 9.

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