Battery winding structure, battery and energy storage device

Abstract

The utility model relates to the technical field of batteries, and discloses a battery winding structure, a battery and an energy storage device. The battery winding structure comprises an integrated winding core structure, wherein the winding core structure comprises a positive electrode adapter plate, a negative electrode adapter plate and two winding cores; the two roll cores are stacked along the thickness direction, the positive electrode tabs between the two roll cores are crossed to form a positive electrode tab bridge, and the negative electrode tabs between the two roll cores are crossed to form a negative electrode tab bridge; the positive pole adapter plate is arranged between the positive pole lug bridge and the roll core and is welded with the positive pole lug bridge; and the negative electrode adapter plate is arranged between the negative electrode lug bridge and the roll core and is welded with the negative electrode lug bridge. According to the utility model, an integrated roll core structure can be obtained through one-time winding, so that the energy density of the battery can be improved; working procedures such as tab matching and pre-welding are omitted, so that the production efficiency can be improved; by reducing a tab welding process, the two roll cores are communicated by using the tabs, so that the rate capability, the service life and the safety performance of the battery are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery winding structure, a battery and an energy storage device. Background Art

[0002] Secondary batteries such as lithium-ion batteries, solid electrolyte batteries, and sodium-ion batteries are widely used in the fields of electric vehicles, 3C digital products, and energy storage due to their advantages of long cycle life, good safety performance, no memory effect, and high charging efficiency. With the increasing consumption of petrochemical energy and the proposal of the zero-carbon concept, the demand for clean secondary batteries is growing. High rate performance and high energy density have become one of the current technical directions for the development of secondary batteries.

[0003] Large wound secondary batteries are usually made by connecting two or four winding cores in parallel internally. After pairing, the pole ears are pre-welded and then welded to the cover plate by transfer welding.

[0004] This solution has the following technical problems:

[0005] 1. The tabs between the cores need to be pre-welded and then bent, which results in a long tab welding path, large occupied space, and large electron transmission impedance, affecting the energy density and rate performance of the battery;

[0006] 2. The tabs need to be paired and pre-welded, which results in low production efficiency. Utility Model Content

[0007] In view of this, the utility model provides a battery winding structure, a battery and an energy storage device to solve the problem of low battery energy density or low production efficiency.

[0008] In the first aspect, the utility model provides a battery winding structure, including an integrated core structure, the core structure including a positive electrode adapter plate, a negative electrode adapter plate and two cores; the two cores are stacked along the thickness direction, the positive electrode tabs between the two cores are crossed to form a positive electrode tab bridge, and the negative electrode tabs between the two cores are crossed to form a negative electrode tab bridge; the positive electrode adapter plate is arranged between the positive electrode tab bridge and the core and welded to the positive electrode tab bridge; the negative electrode adapter plate is arranged between the negative electrode tab bridge and the core and welded to the negative electrode tab bridge.

[0009] Beneficial effects: Compared with the traditional structure of multiple winding cores connected in series to form a large battery cell, the battery winding structure provided by the utility model can obtain an integrated winding core structure through one winding. Since the space for welding and folding the pole ears between the single battery cells is reduced and the distance between the pole ears and the top of the battery is shortened, the energy density of the battery can be improved to a certain extent. At the same time, the processes of pole ear assembly and pre-welding are omitted, which can improve production efficiency; and by reducing the pole ear welding process and connecting the two winding cores with the pole ears, the positive electrode adapter is inserted between the positive pole ear bridge and the winding core, and the negative electrode adapter is inserted between the negative pole ear bridge and the winding core, which improves the welding strength of the pole ears, shortens the bending length of the pole ears, and improves the rate performance, energy density, life and safety performance of the battery.

[0010] In an optional embodiment, two winding cores of a winding core structure are formed by winding the positive electrode sheet, the negative electrode sheet and the separator once.

[0011] In an optional embodiment, the positive electrode sheet includes two positive electrode winding sheets arranged in parallel along the width direction, and the two positive electrode winding sheets are connected by a number of positive electrode tabs; the negative electrode sheet includes two negative electrode winding sheets arranged in parallel along the width direction, and the two negative electrode winding sheets are connected by a number of negative electrode tabs; and the separator is arranged between the positive electrode winding sheet and the negative electrode winding sheet.

[0012] In an optional embodiment, the positive electrode tabs of the positive electrode sheet are arranged in groups of two and tilted toward each other, and the negative electrode tabs of the negative electrode sheet are arranged in groups of two and tilted toward each other.

[0013] In an optional embodiment, along the direction from the beginning to the end of the winding direction, the length of each group of positive electrode tabs increases gradually, and the length of each group of negative electrode tabs increases gradually.

[0014] In an optional embodiment, the positive electrode adapter is provided with a raised positive electrode post, and the negative electrode adapter is provided with a raised negative electrode post.

[0015] In an optional embodiment, the positive electrode column and the negative electrode column are both close to or located at the junction of the two winding cores.

[0016] In an optional embodiment, the battery winding structure further includes an insulating mesh, and the positive electrode adapter and the negative electrode adapter are arranged on the insulating mesh, and the insulating mesh is arranged toward one side of the winding core. In this way, the insulation between the positive electrode adapter or the negative electrode adapter and the electrode of the battery cell can be ensured.

[0017] In a second aspect, the utility model further provides a battery, comprising the battery winding structure of any one of the above embodiments, as well as a top cover plate and an insulating plate. The top cover plate is provided with a positive pole cap and a negative pole cap; the insulating plate is provided with a positive pole mounting hole and a negative pole mounting hole; the positive pole of the battery winding structure passes through the positive pole mounting hole and is conductively connected to the positive pole cap; the negative pole of the battery winding structure passes through the negative pole mounting hole and is conductively connected to the negative pole cap.

[0018] Because the battery includes a battery winding structure, it has the same effect as the battery winding structure and is not described in detail here.

[0019] In a third aspect, the utility model further provides an energy storage device, comprising the battery of any one of the above embodiments.

[0020] Since the energy storage device includes a battery and has the same effect as the battery, it will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a schematic structural diagram of a positive electrode sheet in a battery winding structure according to an embodiment of the utility model;

[0023] Figure 2 This is a schematic structural diagram of a negative electrode sheet in a battery winding structure according to an embodiment of the utility model;

[0024] Figure 3 This is a schematic diagram of stacking materials in a battery winding structure according to an embodiment of the utility model;

[0025] Figure 4 Reason Figure 3 A schematic diagram of the structure of the integrated winding core structure formed after the material is wound is in a flat state;

[0026] Figure 5 for Figure 4 The schematic diagram of the structure of the winding core structure shown is in a folded state along the thickness direction;

[0027] Figure 6 For adapter and Figure 5 The structural schematic diagram of the assembly method of the winding core structure shown;

[0028] Figure 7 for Figure 6The schematic diagram of the structure after the adapter sheet and the winding core structure are assembled is shown;

[0029] Figure 8 for Figure 7 Schematic diagram of the exploded structure between the winding core structure, the top cover plate and the insulation plate.

[0030] Description of reference numerals:

[0031] 1. Positive electrode sheet; 11. Positive electrode winding sheet; 12. Positive electrode ear; 2. Negative electrode sheet; 21. Negative electrode winding sheet; 22. Negative electrode ear; 3. Diaphragm; 4. Positive electrode adapter sheet; 5. Negative electrode adapter sheet; 6. Positive electrode ear bridge; 7. Negative electrode ear bridge; 8. Positive electrode column; 9. Negative electrode column; 10. Insulating mesh; 20. Top cover plate; 201. Positive electrode column cap; 202. Negative electrode column cap; 30. Insulating plate; 301. Positive electrode mounting hole; 302. Negative electrode mounting hole; 40. Explosion-proof valve; 50. Liquid injection port; 100. Winding core; 1000. Winding core structure. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0033] Combine the following Figures 1 to 8 , describing an embodiment of the utility model.

[0034] According to an embodiment of the utility model, in the first aspect, a battery winding structure is provided, including an integrated core structure 1000, the core structure 1000 includes a positive electrode adapter sheet 4, a negative electrode adapter sheet 5 and two cores 100; the two cores 100 are stacked along the thickness direction, the positive electrode tabs 12 between the two cores 100 are crossed to form a positive electrode tab bridge 6, and the negative electrode tabs 22 between the two cores 100 are crossed to form a negative electrode tab bridge 7; the positive electrode adapter sheet 4 is arranged between the positive electrode tab bridge 6 and the core 100 and is welded to the positive electrode tab bridge 6; the negative electrode adapter sheet 5 is arranged between the negative electrode tab bridge 7 and the core 100 and is welded to the negative electrode tab bridge 7.

[0035] Compared with the traditional structure of multiple winding cores connected in series to form a large battery cell, the battery winding structure provided by the embodiment of the utility model can obtain an integrated winding core structure through one winding. Since the space for welding and folding the tabs between the single battery cells is reduced and the distance between the tabs and the top of the battery is shortened, the energy density of the battery can be improved to a certain extent. At the same time, the processes of tab assembly and pre-welding are omitted, which can improve production efficiency; and by reducing the tab welding process and connecting the two winding cores 100 with the tabs, the positive electrode adapter 4 is inserted between the positive pole tab bridge 6 and the winding core 100, and the negative electrode adapter 5 is inserted between the negative pole tab bridge 7 and the winding core 100, the tab welding strength is improved, the tab bending length is shortened, and the battery rate performance, battery energy density, life and safety performance are improved.

[0036] In related technologies, large-scale wound secondary batteries are mostly realized by connecting two or four winding cores in parallel internally. After pairing, the pole ears are pre-welded and then welded to the cover plate by transfer welding. This solution is prone to problems such as welding through and cold welding, resulting in low tensile strength. Under abnormal external forces, the battery will fail due to pole ear detachment and fracture, affecting the battery's electrical performance and safety performance.

[0037] The positive electrode tabs 12 between the two winding cores 100 are arranged in pairs and crosswise, and the negative electrode tabs 22 between the two winding cores 100 are arranged in pairs and crosswise.

[0038] The positive electrode tab 12 and the negative electrode tab 22 are arranged in this cross-arrangement manner. After crossing, the restraint force between the layers of the tabs can make the tabs fit more closely, thereby effectively avoiding welding problems such as cold welding and welding penetration during the welding process, and improving the yield rate of the welding process.

[0039] By connecting the positive electrode adapter 4 and the positive electrode tab 12, and the negative electrode adapter 5 and the negative electrode tab 22, the battery cell can be electrically conductive to the outside. Specifically, the positive electrode adapter 4 and the positive electrode tab 12 are connected by welding. Since the positive electrode tabs 12 are arranged in multiple groups, each group contains at least two tabs, after being wound into a battery cell, the two positive electrode tabs 12 in each group can overlap to form an "X"-shaped cross structure, or can form two or more "X"-shaped cross structures. Regardless of the number of cross structures formed by the positive electrode tabs 12, they are all welded to the positive electrode adapter 4. The implementation method on the negative electrode side is the same and will not be repeated here.

[0040] Since the two winding cores 100 are stacked in the thickness direction, the positive pole tab 12 and the negative pole tab 22 between the two winding cores 100 are bent, and a positive pole tab bridge 6 and a negative pole tab bridge 7 are formed to bridge the two winding cores 100. Since the positive pole tab bridge 6 and the negative pole tab bridge 7 are the connection structures between the two winding cores 100, the pre-welding process can be avoided, and they can be connected to the adapter through one welding, which reduces the welding points, reduces the ohmic resistance of the battery cell, improves the electron transmission rate, and improves the rate performance of the battery. Compared with the traditional structure of welding multiple battery cell tabs together, the cross-type tab is a continuous structure. The continuous tab structure reduces the risk of tab pulling and tearing under abnormal external forces such as vibration, collision, and falling, and improves the safety and stability of the battery.

[0041] In some embodiments, two winding cores 100 of a winding core structure 1000 are formed by winding the positive electrode sheet 1 , the negative electrode sheet 2 and the separator 3 once.

[0042] The battery winding structure provided in the embodiment of the utility model can obtain an integrated core structure 1000 through one winding. Due to the reduction of auxiliary materials between the cores 100 and 100 (tape, 3 layers of the tail diaphragm, etc.), the energy density of the battery can be improved to a certain extent.

[0043] In some embodiments, the positive electrode sheet 1 includes two positive electrode winding sheets 11 arranged in parallel along the width direction, and the two positive electrode winding sheets 11 are connected by a plurality of positive electrode tabs 12; the negative electrode sheet 2 includes two negative electrode winding sheets 21 arranged in parallel along the width direction, and the two negative electrode winding sheets 21 are connected by a plurality of negative electrode tabs 22; the separator 3 is arranged between the positive electrode winding sheet 11 and the negative electrode winding sheet 21.

[0044] Specifically, the middle of the positive electrode sheet 1 can be cut by laser die-cutting to form two positive electrode winding sheets 11 with multiple tabs in the middle, and the spaces between adjacent tabs are hollowed out. The negative electrode sheet 2 can be arranged in the same manner.

[0045] Specifically, the materials are stacked in the order of the separator 3 , the negative electrode sheet 2 , the separator 3 and the positive electrode sheet 1 .

[0046] Furthermore, in some embodiments, the positive electrode tabs 12 of the positive electrode sheet 1 are arranged in pairs and tilted toward each other.

[0047] In this way, after the positive electrode sheet 1 is wound to form the winding core 100, the positive electrode tabs 12 can be crossed with each other, so that there is a restraining force between the layers of the positive electrode tabs 12, ensuring the firmness of the welding between the positive electrode tabs 12 and the positive electrode adapter 4. The negative electrode sheet 2 has the same effect, which will not be repeated here.

[0048] In some embodiments, along the direction from the beginning to the end of the winding direction, the length of each group of the positive electrode tabs 12 increases, and the length of each group of the negative electrode tabs 22 increases, that is, the lengths of the positive electrode tabs 12 and the negative electrode tabs 22 in different groups show an increasing trend along the direction from the beginning to the end of the winding direction, but the lengths of the two positive electrode tabs 12 or the two negative electrode tabs 22 in each group are the same.

[0049] With this arrangement, the positive electrode tab 12 and the negative electrode tab 22 can effectively adjust the length of the inner and outer tabs, avoiding problems such as tab wrinkles, breakage, and poor interlayer bonding that affect welding due to uneven stress during the folding process, thereby effectively improving the welding process yield and battery cell rate performance.

[0050] It can be understood that since the positive electrode tab 12 connects two positive electrode winding sheets 11, the longer the length of the positive electrode tab 12, the smaller the angle between the positive electrode tab 12 and the edge of the positive electrode winding sheet 11 along the length direction. Of course, in some embodiments, the positive electrode tab 12 can also be arranged perpendicular to the edge of the positive electrode winding sheet 11 along the length direction. However, compared with this scheme, the positive electrode tab 12 is arranged at an angle, and the length of the positive electrode tab 12 of the inner and outer layers can be changed by adjusting the inclination angle of the positive electrode tab 12, so that the length of the positive electrode tab 12 of the inner and outer layers forms a gradient distribution, thereby reducing the uneven stress of the positive electrode tab 12 during the folding and closing of the battery cell after winding, which causes the tab wrinkles, fractures, and poor interlayer contact. The negative electrode tab 22 adopts the same implementation method and has the same technical effect, which will not be repeated here. Specifically, the "inner and outer layers" here refer to the winding core 100, that is, the positive electrode tab 12 near the beginning of the winding direction is located in the inner layer of the winding core 100 after winding, and the positive electrode tab 12 near the end of the winding direction is located in the outer layer of the winding core 100 after winding.

[0051] In some embodiments, the battery winding structure further includes an insulating mesh 10, on which the positive electrode adapter 4 and the negative electrode adapter 5 are disposed, and the insulating mesh 10 is disposed toward one side of the winding core 100. This ensures that the positive electrode adapter 4 or the negative electrode adapter 5 is insulated from the end surface of the winding core 100.

[0052] In some embodiments, the positive electrode adapter plate 4 is provided with a raised positive electrode column 8 , and the negative electrode adapter plate 5 is provided with a raised negative electrode column 9 .

[0053] The positive electrode post 8 is used for conductive connection with the positive side of the top cover plate 20 of the battery, and the negative electrode post 9 is used for conductive connection with the negative side of the top cover plate 20 of the battery.

[0054] In some embodiments, the positive electrode column 8 and the negative electrode column 9 are both close to or located at the junction of the two winding cores 100. This arrangement is conducive to stabilizing the electrical conduction performance.

[0055] Compared with the battery in the related art that adopts the solution of internal multiple winding cores in parallel, the battery winding structure provided in this embodiment forms an integrated winding core structure 1000 through a single winding, which improves the production efficiency while also improving the strength of the pole ear after welding. The pole ear can be integrated into the adapter through a single welding, thereby improving the rate performance and safety performance of the battery.

[0056] According to an embodiment of the utility model, in a second aspect, a battery is further provided, comprising a battery winding structure according to any one of the above embodiments, and a top cover plate 20 and an insulating plate 30. The top cover plate 20 is provided with a positive pole cap 201 and a negative pole cap 202; the insulating plate 30 is provided with a positive pole mounting hole 301 and a negative pole mounting hole 302; the positive pole 8 of the battery winding structure passes through the positive pole mounting hole 301 and is conductively connected to the positive pole cap 201; the negative pole 9 of the battery winding structure passes through the negative pole mounting hole 302 and is conductively connected to the negative pole cap 202.

[0057] This arrangement enables the insulating plate 30 and the top cover plate 20 of the battery cell to be connected to transfer electrical energy to the outside.

[0058] In some embodiments, the top cover plate 20 is provided with an explosion-proof valve 40 , and the explosion-proof valve 40 is arranged corresponding to the gap between the two winding cores 100 .

[0059] Since the explosion-proof valve 40 is arranged corresponding to the gap between the two winding cores 100, that is, along the height direction of the winding core 100, as shown in FIG. Figure 5 In the direction indicated by X, the projection of the explosion-proof valve 40 is located in the gap between the two winding cores 100, that is, the projection of the explosion-proof valve 40 is located Figure 8 In the area indicated by the dotted box at A in the middle, this is conducive to the exhaust of the battery and improves the safety performance of the battery.

[0060] Furthermore, the top cover plate 20 is also provided with a liquid injection port 50, such as Figure 8 As shown, the liquid injection port 50 is disposed close to or located at the gap between the two winding cores 100. This is beneficial to the infiltration of the electrolyte.

[0061] According to an embodiment of the present utility model, in a third aspect, there is also provided an energy storage device, comprising the battery of any one of the above embodiments.

[0062] Because the energy storage device includes a battery winding structure, it has the same effect as the battery winding structure and will not be described in detail here.

[0063] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery winding structure, characterized in that: It comprises an integrated winding core structure (1000), wherein the winding core structure (1000) comprises a positive electrode adapter sheet (4), a negative electrode adapter sheet (5) and two winding cores (100); The two winding cores (100) are stacked in the thickness direction, the positive electrode tabs (12) between the two winding cores (100) cross to form a positive electrode tab bridge (6), and the negative electrode tabs (22) between the two winding cores (100) cross to form a negative electrode tab bridge (7); The positive electrode adapter sheet (4) is arranged between the positive electrode tab bridge (6) and the winding core (100) and is welded to the positive electrode tab bridge (6); the negative electrode adapter sheet (5) is arranged between the negative electrode tab bridge (7) and the winding core (100) and is welded to the negative electrode tab bridge (7).

2. The battery winding structure according to claim 1, characterized in that: The two winding cores (100) of a winding core structure (1000) are formed by winding a positive electrode sheet (1), a negative electrode sheet (2) and a separator (3) once.

3. The battery winding structure according to claim 2, characterized in that: The positive electrode sheet (1) comprises two positive electrode winding sheets (11) arranged in parallel along the width direction, and the two positive electrode winding sheets (11) are connected via a plurality of positive electrode tabs (12); The negative electrode sheet (2) comprises two negative electrode winding sheets (21) arranged in parallel along the width direction, and the two negative electrode winding sheets (21) are connected via a plurality of negative electrode tabs (22); The separator (3) is arranged between the positive electrode wound sheet (11) and the negative electrode wound sheet (21).

4. The battery winding structure according to claim 3, characterized in that: The positive pole tabs (12) of the positive pole sheet (1) are arranged in pairs and tilted toward each other, and the negative pole tabs (22) of the negative pole sheet (2) are arranged in pairs and tilted toward each other.

5. The battery winding structure according to claim 4, characterized in that: Along the direction from the beginning to the end of the winding direction, the length of each group of positive electrode tabs (12) increases gradually, and the length of each group of negative electrode tabs (22) increases gradually.

6. The battery winding structure according to any one of claims 1 to 5, characterized in that: The positive electrode adapter plate (4) is provided with a raised positive electrode pole (8), and the negative electrode adapter plate (5) is provided with a raised negative electrode pole (9).

7. The battery winding structure according to claim 6, characterized in that: The positive electrode column (8) and the negative electrode column (9) are both close to or located at the junction of the two winding cores (100).

8. The battery winding structure according to any one of claims 1 to 5, characterized in that: It also comprises an insulating mesh (10), the positive electrode adapter plate (4) and the negative electrode adapter plate (5) are arranged on the insulating mesh (10), and the insulating mesh (10) is arranged toward one side of the winding core (100).

9. A battery, characterized in that: include: The battery winding structure according to any one of claims 1 to 8; A top cover plate (20), wherein the top cover plate (20) is provided with a positive pole cap (201) and a negative pole cap (202); An insulating plate (30), wherein the insulating plate (30) is provided with a positive electrode mounting hole (301) and a negative electrode mounting hole (302); The positive pole post (8) of the battery winding structure passes through the positive pole mounting hole (301) and is conductively connected to the positive pole post cap (201); the negative pole post (9) of the battery winding structure passes through the negative pole mounting hole (302) and is conductively connected to the negative pole post cap (202).

10. An energy storage device, characterized in that: A battery comprising the battery of claim 9.

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