Battery cell structure and battery with same

Abstract

The utility model discloses a battery cell structure and a battery with the battery cell structure, the battery cell structure comprises a pole piece, the pole piece comprises a first side surface and a second side surface which are oppositely arranged along the length direction; the tabs are arranged on the pole pieces and are connected with the pole pieces; wherein the tabs comprise a first tab and a second tab, the first tab and the second tab are arranged at an interval along the length direction of the pole piece, and the first tab is close to the first side surface relative to the second tab; the horizontal distance between the center line of the first tab and the first side surface is X1, the horizontal distance between the first side surface and the second side surface is L, and 0.2 * L < = X1 < = 0.3 * L. The battery cell structure solves the problem that the use safety of the battery cell structure in the prior art is relatively low.

Description

Technical Field

[0001] The present application relates to the technical field of battery cell structure design, and in particular to a battery cell structure and a battery having the same. Background Art

[0002] Ion batteries are widely used in the field of new energy due to their many advantages such as high energy density, excellent power performance and long cycle life.

[0003] In the process of manufacturing ion batteries, the current collector is an important component, which is mainly welded to the tab and is used to gather and conduct the current of the positive or negative electrode materials of the battery. The composite current collector has a sandwich structure, that is, metal conductive layers are respectively arranged on both sides of the polymer support layer. It is used to replace the battery cells prepared by traditional rolled aluminum foil or electrolytic copper foil, and has the advantages of high safety, high specific energy, long life, low cost and high compatibility.

[0004] The thickness of the conductive layer of the composite current collector is mostly around 1 micron, which is thinner than the thickness of the conductive layer of the traditional metal current collector. This results in a larger current collector resistance and the presence of current-intensive areas. At high rates, the temperature of the current-intensive areas of the composite current collector will increase significantly, reducing the safety of the battery cell. Utility Model Content

[0005] The main purpose of the present application is to provide a battery cell structure and a battery having the same, so as to solve the problem of low safety of battery cell structures in the prior art.

[0006] According to one aspect of the present application, a battery cell structure is provided, including: a pole piece, the pole piece including a first side surface and a second side surface arranged opposite to each other along the length direction; a pole lug, arranged on the pole piece and connected to the pole piece; wherein the pole lug includes a first pole lug and a second pole lug, the first pole lug and the second pole lug are arranged at intervals along the length direction of the pole piece, and the first pole lug is closer to the first side surface relative to the second pole lug; the horizontal distance between the center line of the first pole lug and the first side surface is X1, and the horizontal distance between the first side surface and the second side surface is L, 0.2×L≤X1≤0.3×L.

[0007] Furthermore, the horizontal distance between the center line of the second tab and the second side surface is X2, 0.2×L≤X2≤0.3

[0008] ×L.

[0009] Furthermore, the capacity of the electrode is I, the cell rate is N, a current-intensive area is provided on the first electrode tab and / or the second electrode tab, and the length of the current-intensive area is m; wherein 2×I×N≤m≤10×I×N.

[0010] Furthermore, the first pole tab is welded to the pole piece, and the projection surface of the first pole tab on the pole piece is a current-intensive area; and / or the second pole tab is welded to the pole piece, and the projection surface of the second pole tab on the pole piece corresponds to the current-intensive area.

[0011] Furthermore, the first pole tab and the pole piece are an integrally formed structure, at least a portion of the current intensive area is located on the first pole tab, and the length of the first pole tab is A1, 0.2×A1≤m≤0.5×A1.

[0012] Furthermore, the second pole tab and the pole piece are an integrally formed structure, at least a portion of the current intensive area is located on the second pole tab, and the length of the second pole tab is A2, 0.2×A2≤m≤0.5×A2.

[0013] Furthermore, the minimum horizontal distance between the first electrode tab and the second electrode tab is H, 0.3×L≤H≤0.5×L.

[0014] Furthermore, the electrode piece includes: a supporting layer, a conductive layer is respectively provided on two opposite side surfaces of the supporting layer, and a first electrode tab and a second electrode tab are respectively provided on the conductive layer; wherein the first electrode tab and the second electrode tab are respectively welded to the conductive layer, or the first electrode tab and the second electrode tab are respectively integrally formed with the conductive layer.

[0015] Furthermore, the thickness of the first electrode tab and / or the second electrode tab is D, 3 μm≤D≤200 μm.

[0016] On the other hand, the present application also provides a battery, including a battery cell structure, which is the battery cell structure described above.

[0017] Compared with the existing technology, the technical solution of this application has at least the following technical effects:

[0018] To address the problem in the prior art that only a single tab is provided on a pole piece, resulting in current concentration in the connection area between the tab and the pole piece, excessive resistance in the current-dense area, a high temperature rise rate, and reduced rate performance and safety performance of the battery cell, the present invention provides a battery cell structure comprising a pole piece and a tab, the pole piece comprising a first side surface and a second side surface disposed opposite each other along the length direction, the tab being disposed on and connected to the pole piece, wherein the tab comprises a first tab and a second tab, the first tab and the second tab being spaced apart along the length direction of the pole piece, the first tab being closer to the first side surface than the second tab; the horizontal distance between the center line of the first tab and the first side surface being X1, the horizontal distance between the first side surface and the second side surface being L, 0.2×L≤X1≤0.3×L. By limiting the relationship between the length of the pole piece and the position of the first tab, i.e., limiting the range, the first tab is placed in an optimal position, thereby increasing the current flow range, reducing the internal resistance of the battery cell, and reducing the temperature rise rate at high rate of the battery cell, thereby improving the rate performance and safety performance of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0020] Figure 1 This is a top view of the structure of the first embodiment of the electrode in the battery core structure disclosed in the present utility model;

[0021] Figure 2 This is a top view of the second embodiment of the electrode in the battery cell structure disclosed in the utility model.

[0022] Figure 3 It is a side view of the pole piece in the battery core structure disclosed in the present utility model.

[0023] The above drawings include the following reference numerals:

[0024] 1. Pole piece; 10. First side surface; 11. Second side surface; 2. Tab; 21. First tab; 22. Second tab;

[0025] 23. Current-intensive area; 12. Support layer; 13. Conductive layer. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as being merely exemplary, not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0029] As mentioned in the background technology, in the existing battery cell structure, a composite current collector is used to replace the battery cell prepared by traditional rolled aluminum foil or electrolytic copper foil. The thickness of the conductive layer of the composite current collector is thinner than that of the traditional current collector, and the length of the current flow area is short, resulting in a larger resistance of the current collector. There are current-intensive areas in the conductive layer. At high rates, the temperature of the current-intensive areas will increase significantly, leading to safety hazards of the battery cell. Therefore, in response to the above technical problems, the utility model provides a battery cell structure, in which a first pole ear 21 and a second pole ear 22 are provided on the pole piece 1, and the first pole ear 21 and the second pole ear 22 are spaced apart along the length direction of the pole piece 1. The length of the overflow area is increased by the first pole ear 21 and the second pole ear 22. In addition, the length of the pole piece 1 is L, and the pole piece 1 includes a first side surface 10 and a second side surface 11 arranged opposite to each other along the length square. The first pole ear 21 is close to the first side surface 10 relative to the second pole ear 22, and the horizontal distance X1 between the center line of the first pole ear 21 and the first side surface 10 is limited to 0.2×L≤X1≤0.3×L. Within this range, when the pole piece 1 is wound or laminated to form a cylindrical or square battery cell, the first pole ear 21 can be in the optimal position to cooperate with the pole column. At the same time, the first pole ear 21 can increase the length of the overflow area of the pole piece 1, reduce the internal resistance of the battery cell, reduce the temperature rise rate at high rate, and improve the safety of the battery cell.

[0030] See also Figures 1 to 3As shown, the utility model provides a battery cell structure, including: a pole piece 1, the pole piece 1 includes a first side surface 10 and a second side surface 11 arranged opposite to each other along the length direction; a pole tab 2, arranged on the pole piece 1 and connected to the pole piece 1; wherein the pole tab 2 includes a first pole tab 21 and a second pole tab 22, the first pole tab 21 and the second pole tab 22 are spaced apart along the length direction of the pole piece 1, and the first pole tab 21 is closer to the first side surface 10 than the second pole tab 22; the horizontal distance between the center line of the first pole tab 21 and the first side surface 10 is X1, and the horizontal distance between the first side surface 10 and the second side surface 11 is L, 0.2×L≤X1≤0.3×L.

[0031] According to the battery cell structure provided by the present invention, it includes a pole piece 1 and a pole tab 2. The pole piece 1 includes a first side surface 10 and a second side surface 11 arranged opposite to each other along the length direction. The pole tab 2 is arranged on the pole piece 1 and connected to the pole piece 1. The pole tab 2 includes a first pole tab 21 and a second pole tab 22. The first pole tab 21 and the second pole tab 22 are spaced apart along the length direction of the pole piece 1. The first pole tab 21 is closer to the first side surface 10 than the second pole tab 22. The horizontal distance between the center line of the first pole tab 21 and the first side surface 10 is X1, and the horizontal distance between the first side surface 10 and the second side surface 11 is L, and 0.2×L≤X1≤0.3×L. By limiting the positional relationship between the length of the pole piece 1 and the first pole tab 21, that is, limiting the range of X1, the first pole tab 21 is placed in the optimal position, thereby increasing the current flow area range, reducing the internal resistance of the battery cell, and reducing the temperature rise rate at high rate of the battery cell, thereby improving the rate performance and safety performance of the battery cell.

[0032] Furthermore, the horizontal distance between the center line of the second pole tab 22 and the second side surface 11 is X2, 0.2×L≤X2≤0.3×L. By limiting the positions of the first pole tab 21 and the second pole tab 22, it is ensured that the first pole tab 21 and the second pole tab 22 can increase the flow range of the current collector, thereby reducing the resistance of the current collector. Among them, if X1 and X2 are too small, the first pole tab 21 and the second pole tab 22 are respectively located near the edge of the pole piece 1. If X1 and X2 are too large, the distance between the first pole tab 21 and the second pole tab 22 becomes smaller, both of which will lead to an increase in the resistance of the current collector and an increase in the internal resistance of the battery cell, thereby resulting in a higher temperature rise rate of the battery cell.

[0033] In a specific implementation, the capacity of the electrode 1 is I (Ah), the cell rate is N, and a current-dense area 23 is provided on the first electrode tab 21 and / or the second electrode tab 22. The length of the current-dense area 23 is m, where 2×I×N≤m≤10×I×N. By defining the relationship between the length of the current-dense area 23, the capacity of the electrode 1, and the cell rate, the length of the current-dense area 23 is adjusted to ensure that the cell internal resistance reaches an optimal value at high rates. Combined with the positional conditions of the first electrode tab 21 and the second electrode tab 22, the cell internal resistance is reduced, thereby improving the rate performance of the cell.

[0034] In the first embodiment provided by the present invention, the first pole tab 21 is welded to the pole piece 1, and the projection surface of the orthographic projection of the first pole tab 21 on the pole piece 1 is the current-intensive area 23; and / or the second pole tab 22 is welded to the pole piece 1, and the projection surface of the orthographic projection of the second pole tab 22 on the pole piece 1 corresponds to the current-intensive area 23. It should be noted that the orthographic projection refers to the projection along the surface perpendicular to the first pole tab 21 and / or the second pole tab 22 onto the surface of the pole piece 1. Since the current on the electrode 1 is discharged through the first electrode 21 and the second electrode 22, after the first electrode 21 is welded to the electrode 1, the joint between the first electrode 21 and the electrode 1 is the current-intensive area 23. By increasing the length of the current-intensive area 23, the current flow area is increased and the collector resistance is reduced. Similarly, after the second electrode 22 is welded to the electrode 1 between the first electrode 21 and the electrode 1, the joint between the second electrode 22 and the electrode 1 is the current-intensive area 23. Combined with the length range of the current-intensive area 23 on the first electrode 21, the overall current flow area of the electrode 1 is increased, so that the battery cell can achieve high-rate output.

[0035] In a second embodiment of the present invention, the first pole tab 21 is integrally formed with the pole piece 1, and at least a portion of the current-dense region 23 is disposed on the first pole tab 21. The length of the first pole tab 21 is A1, and m is in the range of 0.2×A1≤m≤0.5×A1. The second pole tab 22 is integrally formed with the pole piece 1, and at least a portion of the current-dense region 23 is disposed on the second pole tab 22. The length of the second pole tab 22 is A2, and 0.2×A2≤m≤0.5×A2. When the first pole tab 21 and the second pole tab 22 are integrally formed with the pole piece 1, the first pole tab 21 and the second pole tab 22 protrude from the side of the pole piece 1. In this case, the relationship between the length of the current-dense region 23 and the length of the first pole tab 21 and the second pole tab 22 is limited, so that the first pole tab 21 and the second pole tab 22 have sufficient length to meet the current overcurrent in the current-dense region 23, thereby preventing excessive temperature rise in the current-dense region 23 during high-rate output of the battery cell. Preferably, A1 ≥ 10 mm, A2 ≥ 10 mm, and the range of m is greater than or equal to 2 mm. In the embodiment provided by the present invention, A1 and A2 are 20 mm respectively, and the range of m is 4 mm to 10 mm. Specifically, m is 4 mm or 5 mm or 6 mm or 7 mm or 8 mm or 9 mm or 10 mm, or m is any value between 5 mm and 8 mm.

[0036] Furthermore, in the specific implementation process, the minimum horizontal distance between the first pole tab 21 and the second pole tab 22 is H, 0.3×L≤H≤0.5×L. By limiting the minimum horizontal distance H between the first pole tab 21 and the second pole tab 22, the first pole tab 21 and the second pole tab 22 can respectively realize the output of the current on the pole piece 1. At the same time, the distance between the first pole tab 21 and the second pole tab 22 can well realize the diversion of the current on the pole piece 1. Compared with the method of providing only one pole piece 1 on the pole piece 1, the current flow area is increased. There will not be only one area where the current is concentrated on the pole piece 1, and the area where the current is concentrated is also dispersed, thereby reducing the internal resistance of the battery cell and improving the rate performance of the battery cell.

[0037] In specific implementation, Figure 3As shown, the electrode piece 1 includes: a support layer 12, a conductive layer 13 is respectively provided on two opposite side surfaces of the support layer 12, and a first electrode tab 21 and a second electrode tab 22 are respectively provided on the conductive layer 13; wherein the first electrode tab 21 and the second electrode tab 22 are respectively welded to the conductive layer 13, or the first electrode tab 21 and the second electrode tab 22 are respectively integrally formed with the conductive layer 13. When the first electrode tab 21 and the second electrode tab 22 are welded to the conductive layer 13, current is conducted to the first electrode tab 21 and the second electrode tab 22 through the conductive layer 13. In this case, the current-dense area 23 is located at the contact surface between the first electrode tab 21 and the second electrode tab 22 and the conductive layer 13. When the first electrode tab 21 and the second electrode tab 22 are integrally formed with the conductive layer 13, current is directly output from the conductive layer 13 to the first electrode tab 21 and the second electrode tab 22. In this case, the current-dense area in the current flow path is located near the first electrode tab 21 and the second electrode tab 22. The first electrode tab 21 and the second electrode tab 22 are used to realize current diversion on the electrode piece 1 , thereby preventing the temperature on the electrode piece 1 from being too high.

[0038] Preferably, the thickness D of the first and / or second electrode tabs 21 and 22 is 3 μm ≤ D ≤ 200 μm. By limiting the thickness of the first and second electrode tabs 21 and 22, the first and second electrode tabs 21 and 22 have sufficient strength and enhance the flow-guiding effect of the first and second electrode tabs 21 and 22. Specifically, D is 3 μm, 10 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, or 200 μm, or any value between 20 μm and 160 μm.

[0039] Compared with the traditional cell structure, the cell structure of the present invention adopts the 18650 cell as an example. The first tab 21 and the second tab 22 adopt the traditional welding method. The internal resistance of the cell increases from 13mΩ to 35mΩ, and the maximum ratio is reduced from 4 to 1.5. When the x=1 / 4L position is adopted and the length m is increased to 58mm, the internal resistance of the cell is 12.4mΩ and the ratio is 4.4, as shown in the following table:

[0040] Example 1: 18650 battery cell

[0041]

[0042]

[0043] In Example 2, taking the blade battery cell as an example, the first tab 21 and the second tab 22 are welded using a traditional welding method. The internal resistance of the cell increases from 1.1 mΩ to 1.9 mΩ, and the maximum ratio is reduced from 2 to 0.8. When the x=1 / 4L position is adopted and the Y length is increased to 80 mm, the internal resistance of the cell is 1.19 mΩ and the ratio is 2.6; as shown in the following table:

[0044]

[0045] The utility model also provides a battery, comprising a battery core structure, and the battery core structure is the battery core structure of the above embodiment.

[0046] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0047] According to the battery cell structure provided by the present invention, it includes a pole piece 1 and a pole tab 2. The pole piece 1 includes a first side surface 10 and a second side surface 11 arranged opposite to each other along the length direction. The pole tab 2 is arranged on the pole piece 1 and connected to the pole piece 1. The pole tab 2 includes a first pole tab 21 and a second pole tab 22. The first pole tab 21 and the second pole tab 22 are spaced apart along the length direction of the pole piece 1. The first pole tab 21 is closer to the first side surface 10 than the second pole tab 22. The horizontal distance between the center line of the first pole tab 21 and the first side surface 10 is X1, and the horizontal distance between the first side surface 10 and the second side surface 11 is L, and 0.2×L≤X1≤0.3×L. By limiting the positional relationship between the length of the pole piece 1 and the first pole tab 21, that is, limiting the range of X1, the first pole tab 21 is placed in the optimal position, thereby increasing the current flow area range, reducing the internal resistance of the battery cell, and reducing the temperature rise rate at high rate of the battery cell, thereby improving the rate performance and safety performance of the battery cell.

[0048] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0049] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0050] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell structure, characterized in that: include: A pole piece (1), the pole piece (1) comprising a first side surface (10) and a second side surface (11) arranged opposite to each other along a length direction; A pole lug (2) is provided on the pole piece (1) and connected to the pole piece (1); The pole lug (2) comprises a first pole lug (21) and a second pole lug (22), the first pole lug (21) and the second pole lug (22) being spaced apart along the length direction of the pole piece (1), and the first pole lug (21) being closer to the first side surface (10) relative to the second pole lug (22); The horizontal distance between the center line of the first tab (21) and the first side surface (10) is X1, the horizontal distance between the first side surface (10) and the second side surface (11) is L, and 0.2×L≤X1≤0.3×L.

2. The battery cell structure according to claim 1, characterized in that: The horizontal distance between the center line of the second tab (22) and the second side surface (11) is X2, 0.2×L≤X2≤0.3×L.

3. The battery core structure according to claim 1, characterized in that: The capacity of the pole piece (1) is I, the cell rate is N, a current-intensive area (23) is provided on the first pole tab (21) and / or the second pole tab (22), and the length of the current-intensive area (23) is m; Among them, 2×I×N≤m≤10×I×N.

4. The battery core structure according to claim 3, characterized in that: The first pole tab (21) is welded to the pole piece (1), and the projection surface of the orthographic projection of the first pole tab (21) on the pole piece (1) is the current-intensive area (23); and / or, The second pole tab (22) is welded to the pole piece (1), and the projection surface of the orthographic projection of the second pole tab (22) on the pole piece (1) corresponds to the current intensive area (23).

5. The battery core structure according to claim 3, characterized in that: The first pole lug (21) and the pole piece (1) are an integrally formed structure, at least a portion of the current-intensive area (23) is located on the first pole lug (21), and the length of the first pole lug (21) is A1, 0.2×A1≤m≤0.5×A1.

6. The battery cell structure according to claim 3, characterized in that: The second pole tab (22) and the pole piece (1) are an integrally formed structure, at least a portion of the current-intensive area (23) is located on the second pole tab (22), and the length of the second pole tab (22) is A2, 0.2×A2≤m≤0.5×A2.

7. The battery core structure according to any one of claims 1 to 6, characterized in that: The minimum horizontal distance between the first pole tab (21) and the second pole tab (22) is H, 0.3×L≤H≤0.5×L.

8. The battery core structure according to any one of claims 1 to 6, characterized in that: The pole piece (1) comprises: A supporting layer (12), conductive layers (13) being respectively provided on two oppositely arranged side surfaces of the supporting layer (12), and the first pole tab (21) and the second pole tab (22) being respectively provided on the conductive layers (13); The first pole tab (21) and the second pole tab (22) are respectively welded to the conductive layer (13), or the first pole tab (21) and the second pole tab (22) are respectively formed into an integral structure with the conductive layer (13).

9. The battery core structure according to any one of claims 1 to 6, characterized in that: The thickness of the first pole tab (21) and / or the second pole tab (22) is D, 3 μm≤D≤200 μm.

10. A battery comprising a cell structure, characterized in that: The battery cell structure is the battery cell structure according to any one of claims 1 to 9.

Images