Winding battery

Abstract

The utility model discloses a winding battery which comprises a winding core main body, tabs and electrode connecting sheets, and the winding core main body is provided with axially opposite end surfaces; the tab is provided with a fixed end and a free end which are opposite in the length direction, the fixed end of the tab is connected with the roll core main body, and the tab is bent and arranged on the side of the end surface of the roll core main body; the electrode connecting piece is provided with a first end and a second end which are opposite in the length direction, the first end of the electrode connecting piece is connected with the free end of the tab, and the second end of the electrode connecting piece is connected with the pole; the electrode connecting sheet is bent; and the tabs are flattened and clamped between the electrode connecting sheets and the end surface of the roll core main body or between the electrode connecting sheets. According to the winding battery, the bending points are arranged on the electrode connecting pieces, so that the extension length of the tabs of the electrode pieces is shortened, and the problem that the tabs are bent inwards in the high-speed winding process of the winding core main body is solved; and the rigidity of the electrode connecting piece is generally greater than that of the tab laminated piece, so that the probability of deflection of the assembly of the electrode connecting piece and the tab when the assembly is transferred to the next process at a high speed is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of battery production, in particular to a wound battery. Background Art

[0002] Multi-electrode winding technology means first cutting a fixed electrode shape on the electrode sheet. After winding, the multi-layered electrodes of the winding core are stacked and led out, and the bent electrodes are connected to the battery poles. The multi-electrode structure of cylindrical batteries is conducive to reducing battery impedance, improving the battery's high-rate charge and discharge performance, and effectively reducing the temperature rise of the battery under high-rate discharge; the battery temperature is low, which significantly increases the battery cycle life. The design production capacity limit of cylindrical batteries is usually greater than 100PPM (100 per minute).

[0003] In order to meet the bending requirements, the tabs extending from the winding core body must have a predetermined length. During the high-speed winding process of the winding core, the tabs are prone to fold inward, which will greatly reduce the quality rate of the winding process; taking the negative electrode as an example, the longer negative tab is connected to the pole through the negative connecting piece, and the total length of the tab and the negative connecting piece is too long, which is easy to be skewed when transferred to the next process at high speed, resulting in a reduction in the quality rate of the negative cover plate laser welding process. Utility Model Content

[0004] One of the purposes of the utility model is to overcome the defects existing in the prior art and provide a wound battery, in which a bending portion is arranged on the electrode connecting sheet, the extension length of the pole ear of the winding core is shortened, and the deformation probability of the pole piece is reduced during the high-speed winding process of the winding core.

[0005] In order to achieve the above technical effects, the technical solution of the utility model is: a wound battery, comprising:

[0006] A winding core body having axially opposite end surfaces;

[0007] The pole ear has a fixed end and a free end opposite to each other in the length direction, the fixed end is connected to the winding core body, and is bent and arranged on the side of the end surface of the winding core body;

[0008] An electrode connecting piece, having a first end and a second end opposite to each other in a length direction, wherein the first end is connected to the free end of the electrode lug, and the second end is connected to the electrode column;

[0009] The electrode connecting sheet is bent; the electrode tab is flattened and clamped between the electrode connecting sheet and the end surface of the winding core body or between the electrode connecting sheets.

[0010] A preferred technical solution is that the flattened length of the electrode connecting sheet is greater than the length of the electrode lug.

[0011] A preferred technical solution is that the electrode tab is connected to the electrode connecting sheet by welding via an overlapping area, and the length of the overlapping area is not less than half of the length of the electrode tab.

[0012] A preferred technical solution is that the tab is flattened and clamped between the electrode connecting sheet and the end surface of the winding core body.

[0013] A preferred technical solution is that the electrode connecting sheet has one bending point.

[0014] A preferred technical solution is that the bending point of the electrode connecting sheet is provided with an arc-shaped bending section.

[0015] A preferred technical solution is that the electrode connecting sheet comprises a first flattened and bent section and a second flattened and bent section connected in the length direction, the first flattened and bent section is connected to the electrode lug, and the second flattened and bent section is connected to the electrode column;

[0016] The length of the first flattened and bent section is greater than that of the second flattened and bent section, and the second flattened and bent section is arranged on a side of the first flattened and bent section away from the winding core body.

[0017] A preferred technical solution is that the pole ear and the second flattened and bent section are staggered in the orthographic projection of the end surface of the winding core body.

[0018] A preferred technical solution is that the pole ear and the second flattened and bent section are respectively disposed on opposite sides of the center of the end surface of the winding core body in an orthographic projection on the end surface of the winding core body.

[0019] A preferred technical solution is that the length of the pole ear is no more than 10 mm.

[0020] The advantages and beneficial effects of the utility model are:

[0021] The tabs in the wound battery are flattened and clamped between the electrode connecting sheet and the end surface of the winding core body, and the bending point is set at the electrode connecting sheet to shorten the extension length of the tabs of the electrode sheet, effectively solving the problem of tab inward folding caused by high-speed winding of the winding core.

[0022] The stiffness of the electrode connecting sheet is usually greater than that of the tab stack. The length configuration of the tab and the electrode connecting sheet helps to reduce the probability of the assembly of the electrode connecting sheet and the tab being skewed when being transferred to the next process at high speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the flattened tab of a wound battery in the prior art;

[0024] Figure 2 yes Figure 1 Schematic diagram of the structure of the tab bending state of the mid-wound battery;

[0025] Figure 3 is a schematic structural diagram of an electrode connecting sheet of a wound battery in an embodiment in a flattened state;

[0026] Figure 4 yes Figure 3 A partial enlarged view of middle A;

[0027] Figure 5 It is a cross-sectional view of the wound battery along the plane where the central axis of the core body is located;

[0028] Figure 6 yes Figure 5 A partial enlarged view of B in the middle;

[0029] Figure 7 It is a structural schematic diagram of the bending structure of the tab and the electrode connecting piece;

[0030] In the figure: 1. winding core body; 2. pole ear;

[0031] 3. Electrode connecting sheet; 301. Arc-shaped bending section; 302. First flattened bending section; 303. Second flattened bending section;

[0032] 4. Pole; 5. Gasket; 6. Metal block;

[0033] b. Overlapping area. DETAILED DESCRIPTION

[0034] The following examples are used to further describe the specific implementation of the present invention. The following examples are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0035] In the description of the present application, it should be noted that, unless otherwise specified, “plurality” means more than two; the terms “upper”, “lower”, “left”, “right”, “inside”, “outside”, etc., indicating directions or positional relationships, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present application.

[0036] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0037] In the description of the present invention, "first", "second" and the like are used to distinguish different objects rather than to describe a specific order or a primary-secondary relationship.

[0038] The battery structure in the prior art is as follows Figure 1-2 As shown, it includes a winding core body 1, a pole ear 2, an electrode connecting sheet 3 and a metal block 6 of a cover plate connected in sequence, and the shadow of the overlapping part of the electrode connecting sheet 3 and the metal block 6 represents the laser welding area; Figure 2 The middle electrode tab has a bending point, and the electrode connecting sheet 3 is flattened and clamped between the bent electrode tab and the cover plate.

[0039] Example

[0040] like Figure 3-7 As shown, the wound battery of the embodiment includes a winding core body 1, a pole ear 2 and an electrode connecting sheet 3. The winding core body 1 has axially opposite end faces; the pole ear 2 has a length direction ( Figure 3 The electrode tab 2 has a fixed end and a free end opposite to each other in the X-direction, the fixed end of the pole tab 2 is connected to the core body 1, and the pole tab 2 is bent and arranged on the side of the end surface of the core body 1; the electrode connecting sheet 3 has a first end and a second end opposite to each other in the length direction, the first end of the electrode connecting sheet 3 is connected to the free end of the pole tab 2, and the second end of the electrode connecting sheet 3 is connected to the pole 4; the electrode connecting sheet 3 is bent; the pole tab 2 is flattened and clamped between the electrode connecting sheet 3 and the end surface of the core body 1 or between the electrode connecting sheets 3.

[0041] The production method of the winding core is that the positive electrode sheet, the negative electrode sheet and the separator are rolled together by the winding needle mechanism of the winding machine, and its main body includes but is not limited to a cylindrical or elliptical cylindrical shape. The pole ear 2 is a single-layer pole ear 2 or a multi-layer pole ear 2, preferably a multi-layer pole ear 2. The pole ear 2 and the electrode sheet in the winding core body 1 can be optionally connected as one piece.

[0042] In the battery structure, the tab 2 connected to the electrode connecting sheet 3 can be selected as a positive tab and / or a negative tab, and the electrode connecting sheet 3 is a corresponding positive connecting sheet and / or a negative connecting sheet.

[0043] The number of bending points of the electrode connecting sheet 3 can be selected to be one or more than two. When the number of bending points of the electrode connecting sheet 3 is one, the electrode connecting sheet 3 is bent in a "V" shape, and the lengths of the bending sections of the connecting sheet located on both sides of the bending point and in a flattened state can be selected to be equal or unequal; when the number of bending points of the electrode connecting sheet 3 is two, the electrode connecting sheet 3 is bent in a "Z" shape, and the electrode connecting sheet 3 is composed of a middle bending section and end bending sections at both ends, the length of the middle bending section is equal to or greater than the length of the end bending section, and the lengths of the two end bending sections can be selected to be the same or different.

[0044] In this embodiment, the tab 2 is a negative tab, and the electrode connecting piece 3 is a negative connecting piece. Specifically, the first end of the negative connecting piece is connected to the free end of the tab 2 by ultrasonic welding, and the second end of the negative connecting piece is connected to the pole 4 by laser welding.

[0045] The first end of the negative electrode connecting sheet is overlapped and welded with the free end of the pole tab 2. The relative position of the pole tab 2 and the electrode connecting sheet 3 in the battery depends on the bending direction of the pole tab 2 and the electrode sheet overlapping region b. When the overlapping region b is folded along the overlapping direction from the electrode connecting sheet 3 to the pole tab 2, the pole tab 2 is flattened and clamped between the electrode connecting sheet 3 and the end surface of the winding core body; when the overlapping region b is folded along the overlapping direction from the pole tab 2 to the electrode connecting sheet 3, the pole tab 2 is clamped between the flattened and bent sections of the electrode connecting sheet 3.

[0046] like Figure 4 As shown, in another preferred embodiment, the flattened length of the electrode connecting sheet 3 is greater than the length of the electrode tab 2. The flattened length of the electrode connecting sheet 3 refers to the length of the electrode connecting sheet 3 after the bending point is unfolded to a straight state.

[0047] In this embodiment, the ratio of the flattened length of the negative electrode connecting sheet to the length of the tab 2 is 1:(1.5-3), preferably 1:(1.7-2.8), and more preferably 1:(1.9-2.5). It can be understood that the length of the tab 2 is based on the size, thickness, material, winding speed, etc. of the tab 2 so as to ensure that there is no obvious inward folding or deformation when the core body 1 is wound at a high speed.

[0048] like Figure 7 As shown, in another preferred embodiment, the tab 2 and the electrode connecting sheet 3 are welded and connected through the overlapping region b, and the length of the overlapping region b is not less than half the length of the tab 2. Compared with the multi-layer tab stacking structure, the electrode connecting sheet 3 usually has a higher rigidity or a larger thickness. If the length of the overlapping region b is too small, the assembly of the tab 2 and the electrode connecting sheet 3 is easily deformed when the battery assembly is transported at a high speed.

[0049] In this embodiment, the ratio of the length of the overlapping region b to the length of the electrode tab 2 is 1:(1.4-1.99), preferably 1:(1.6-1.9), and more preferably 1:(1.7-1.85).

[0050] like Figure 5-7 As shown, in another preferred embodiment, the electrode tab 2 is flattened and sandwiched between the electrode connecting sheet 3 and the end surface of the winding core body 1 .

[0051] During the bending process, the bending knife is used to bend the electrode connecting sheet 3 with greater rigidity, which is beneficial to reduce the damage to the electrode connecting sheet 3 caused by the pressing force between the bending knife and the electrode connecting sheet 3. Figure 4As shown by the unidirectional arrow in the figure, the contact area is the dot-dash line of the electrode connecting sheet 3. In addition, the bend of the electrode connecting sheet 3 is folded toward the side of the tab stacking structure, and the welding structure of the tab 2 and the electrode connecting sheet 3 is more stable; on the contrary, the bend of the electrode connecting sheet 3 is folded away from the tab stacking structure, and the anti-deformation ability of the tab 2 itself makes the tab stacking structure have a tendency to detach from the electrode connecting sheet 3 and destroy the welding structure of the tab 2 and the electrode connecting sheet 3.

[0052] like Figure 7 As shown, in another preferred embodiment, the number of bending points of the electrode connecting sheet 3 is one. The electrode connecting sheet 3 has a predetermined thickness, and the more bending points there are, the greater the height space occupied by the folded electrode connecting sheet 3 in the axial direction of the winding core body, which is not conducive to maintaining a high utilization rate of the internal space of the battery; or increases the probability that the electrode connecting sheet 3 wears the end surface gasket 5 of the winding core body.

[0053] like Figure 7 As shown, in another preferred embodiment, the bending point of the electrode connecting sheet 3 is provided with an arc-shaped bending section 301 .

[0054] The electrode connecting sheet 3 has a predetermined thickness, and the arc-shaped bending section 301 is provided due to the bending radius of the electrode connecting sheet 3. Furthermore, the arc-shaped bending section 301 has a first surface facing the end face of the core body and a second surface away from the end face of the core body, and the first surface is approximately parallel to the end face of the core body; when the core body 1 vibrates during use of the battery, the contact surface between the first surface and the gasket 5 on the end face of the core body tends to be larger, which is conducive to dispersing the force of the arc-shaped bending section 301 on the gasket 5.

[0055] like Figure 7 As shown, in another preferred embodiment, the electrode connecting sheet 3 includes a first flattened bent section 302 and a second flattened bent section 303 connected in the length direction, the first flattened bent section 302 is connected to the pole ear 2, and the second flattened bent section 303 is connected to the pole 4; the length of the first flattened bent section 302 is greater than the length of the second flattened bent section 303, and the second flattened bent section 303 is arranged on the side of the first flattened bent section 302 away from the winding core body 1.

[0056] On the basis of satisfying the connection with the pole 4, the length of the second flattened and bent section 303 is set to be smaller, so as to reduce the length of the electrode connecting piece 3. In this embodiment, the second flattened and bent section 303 is connected to the pole 4 of the cover plate through the metal block 6, and the second flattened and bent section 303 is connected to the area of ​​the metal block close to the bending point of the electrode connecting piece.

[0057] like Figure 4As shown, in the battery assembly before the electrode connecting piece 3 is bent, the cover surface of the cover plate is perpendicular or approximately perpendicular to the end face of the core body. When the second flattened bending section 303 is connected to the area of ​​the metal block away from the bending point of the electrode connecting piece, the distance between the bottom end of the cover plate and the end face of the core body or the shell port is too small, which is not conducive to the use of corresponding bending equipment such as bending jaws to process the electrode connecting piece 3; on the contrary, the second flattened bending section 303 is connected to the area of ​​the metal block close to the bending point of the electrode connecting piece, which effectively increases the distance between the bottom end of the cover plate and the end face of the core body or the shell port. Usually, the distance is greater than or equal to 5 mm, which facilitates the setting of the bending jaws and helps to achieve 100ppm high-speed automated production.

[0058] like Figure 6 , 7 As shown, in another preferred embodiment, the tab 2 and the second flattened bent section 303 are staggered in the orthographic projection of the end surface of the winding core body 1. The above structure is conducive to reducing the height space occupied by the tab 2 and the electrode connecting sheet 3 assembly in the axial direction of the winding core body.

[0059] As shown in Figures 6 and 7, in another preferred embodiment, the tab 2 and the second flattened and bent section 303 are respectively disposed on opposite sides of the center of the end surface of the core body 1 in the orthographic projection of the end surface of the core body 1. The multi-layer tab superposition structure and the second flattened and bent section 303 are respectively superimposed on the two ends of the first flattened and bent section 302, and the multi-layer tab superposition structure and the second flattened and bent section 303 are respectively disposed on both sides of the first flattened and bent section 302 along the axial direction of the core body, and the multi-layer tab superposition structure provides the arc-shaped bent section 301 with an axial accommodation space for the core body.

[0060] In some embodiments, the length of the tab 2 is no greater than 10 mm. Optionally, the length of the tab 2 includes, but is not limited to, 8 mm, 9 mm, 10 mm, and 11 mm. Further, the flattened length of the tab 2 and the electrode connecting sheet 3 assembly is 22 to 27 mm, including, but not limited to, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, and 27 mm.

[0061] It is understandable that the wound battery also includes known components such as a stop frame integrated with the cover plate, a shell for accommodating the winding core body, and an insulating layer attached to the folded surface of the electrode connecting piece.

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A wound battery comprising: A winding core body having axially opposite end surfaces; The pole ear has a fixed end and a free end opposite to each other in the length direction, the fixed end is connected to the winding core body, and is bent and arranged on the side of the end surface of the winding core body; The electrode connecting piece has a first end and a second end opposite to each other in the length direction, the first end is connected to the free end of the pole ear, and the second end is connected to the pole; characterized in that; The electrode connecting sheet is bent; the electrode tab is flattened and clamped between the electrode connecting sheet and the end surface of the winding core body or between the electrode connecting sheets.

2. The wound battery according to claim 1, characterized in that: The flattened length of the electrode connecting sheet is greater than the length of the electrode tab.

3. The wound battery according to claim 1, characterized in that: The electrode tab is connected to the electrode connecting sheet by welding through an overlapping area, and the length of the overlapping area is not less than half of the length of the electrode tab.

4. The wound battery according to claim 1, characterized in that: The tab is flattened and sandwiched between the electrode connecting sheet and the end surface of the winding core body.

5. The wound battery according to claim 1, characterized in that: The electrode connecting sheet has one bending point.

6. The wound battery according to claim 1, characterized in that: The bending point of the electrode connecting sheet is provided with an arc-shaped bending section.

7. The wound battery according to claim 1 or 6, characterized in that: The electrode connecting sheet comprises a first flattened and bent section and a second flattened and bent section connected in a length direction, the first flattened and bent section is connected to the electrode lug, and the second flattened and bent section is connected to the electrode column; The length of the first flattened and bent section is greater than that of the second flattened and bent section, and the second flattened and bent section is arranged on a side of the first flattened and bent section away from the winding core body.

8. The wound battery according to claim 7, characterized in that: The pole ear and the second flattened and bent section are staggered in the orthographic projection of the end surface of the winding core body.

9. The wound battery according to claim 7, characterized in that: The pole ear and the second flattened and bent section are respectively disposed on two opposite sides of the center of the end surface of the winding core body in an orthographic projection on the end surface of the winding core body.

10. The wound battery according to claim 1, characterized in that: The length of the pole ear is not more than 10 mm.

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