Battery and battery pack

Abstract

The battery comprises a cylindrical roll core, the cylindrical roll core comprises pole pieces, diaphragms and tabs, the pole pieces comprise a positive pole piece and a negative pole piece, the tabs comprise a positive tab and a negative tab, the positive tab is arranged on the side edge of the positive pole piece, the negative tab is arranged on the side edge of the negative pole piece, and the diaphragms are arranged between the positive pole piece and the negative pole piece; in the state that the cylindrical roll core is unfolded, a plurality of tabs are arranged on one side of the pole piece in the first direction at intervals in the length direction, a gap is formed between every two adjacent tabs, the distance between one end, close to the pole piece, of each gap and the pole piece is h1mm, and one side, close to the tabs, of each diaphragm extends out of the pole piece in the first direction; the distance between the side, close to the tab, of the diaphragm and the side, provided with the tab, of the pole piece is h2 mm, and h1 is larger than h2. According to the battery, the diaphragm and the pole piece can be prevented from wrinkling to influence the performance of the battery, and the structural strength of the tabs is also ensured.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery and battery pack. Background Technology

[0002] Currently, lithium-ion batteries can be classified into various types based on their shape, including cylindrical batteries, prismatic batteries, pouch batteries, and button batteries. Cylindrical batteries consist of a cylindrical casing and a core within the casing. The core is formed by winding a positive electrode plate, a negative electrode plate, and a separator between the positive and negative electrodes. The positive electrode plate has a positive tab extending outwards, and the negative electrode plate has a negative tab extending outwards. After the core is wound, the positive and negative tabs need to be folded to the end face of the core so that they can be connected to the positive and negative terminals of the cylindrical battery.

[0003] Because when the electrode tab is folded after the core is wound, the electrode sheet and diaphragm are prone to wrinkling, which also affects the overall structural strength of the electrode tab. Utility Model Content

[0004] The primary objective of this invention is to provide a battery that avoids wrinkling of the separator and electrode sheets, which would affect battery performance, and also ensures the structural strength of the tabs.

[0005] Another objective of this invention is to provide a battery pack using the aforementioned battery.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0007] A battery includes a cylindrical core, the cylindrical core including an electrode, a separator, and tabs, the electrode including a positive electrode and a negative electrode stacked together, the tab including a positive tab and a negative tab, the positive tab extending outward from the side of the positive electrode, the negative tab extending outward from the side of the negative electrode, and the separator being disposed between the positive electrode and the negative electrode;

[0008] When the cylindrical core is unfolded, the width direction of the electrode sheet is the first direction, the length direction of the electrode sheet is the second direction, and multiple tabs are spaced apart along the length direction on one side of the electrode sheet in the first direction. A gap is formed between two adjacent tabs. The gap extends along the first direction and is open at the end of the gap away from the electrode sheet. There is a distance h1mm between the end of the gap near the electrode sheet and the electrode sheet. The diaphragm extends beyond the electrode sheet along the first direction on the side near the tab. The distance between the side of the diaphragm near the tab and the side of the electrode sheet with the tab is h2mm, where h1>h2.

[0009] This utility model also relates to a battery pack, including the aforementioned battery.

[0010] Compared with the prior art, the battery of this utility model embodiment has the following advantages:

[0011] In this invention, during the manufacturing of the cylindrical core, the positive electrode sheet, separator, and negative electrode sheet are stacked together, with the separator located between the positive and negative electrode sheets. Then, the positive electrode sheet, separator, and negative electrode sheet are wound along a second direction to form the cylindrical core. After the electrode sheet and separator are wound, the tabs on the electrode sheet need to be folded onto the end face of the cylindrical core. Among the multiple tabs, the gap between two adjacent tabs can be used to position the folding position of the tab, allowing the tab to start folding in the area near the end of the electrode sheet. At the same time, since h1 > h2, the gap between two adjacent tabs is located in the area where the tab extends beyond the separator. Therefore, when the tab is folded, the separator will not be wrinkled, avoiding contact between the positive and negative electrode sheets and causing a short circuit. Furthermore, the separator material is relatively soft. If the separator wrinkles, it will cause uneven surface height, which will result in poor surface height consistency after the tab is folded, affecting subsequent welding and easily leading to poor welding. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a cylindrical winding core according to an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of the unfolding of the cylindrical core according to an embodiment of the present invention;

[0014] Figure 3 This is a schematic diagram showing the unfolded positive electrode sheet and separator according to an embodiment of the present invention;

[0015] Figure 4 This is a schematic diagram of the unfolded negative electrode sheet and separator according to an embodiment of the present invention;

[0016] Figure 5 This is a schematic diagram of the unfolding of a cylindrical core according to another embodiment of the present invention.

[0017] In the figure, 100 is the cylindrical core; 101 is the core layer; 1 is the electrode sheet; 11 is the positive electrode sheet; 12 is the negative electrode sheet; 2 is the diaphragm; 3 is the tab; 31 is the positive tab; 32 is the negative tab; 33 is the first connecting part; 34 is the second connecting part; and 4 is the gap. Detailed Implementation

[0018] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0019] In the description of this utility model, it should be understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, parts, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, parts, components, and / or groups thereof. It should be understood that when we say a part is "connected" to another part, it can be directly connected to the other part, or there may be intermediate parts. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0020] like Figure 1 and Figure 4 As shown, this utility model relates to a battery, including a cylindrical core 100. The cylindrical core 100 includes an electrode 1, a separator 2, and tabs 3. The electrode 1 includes a positive electrode 11 and a negative electrode 12 stacked together. The tabs 3 include a positive tab 31 and a negative tab 32. The positive tab 31 extends outward from the side of the positive electrode 11, and the negative tab 32 extends outward from the side of the negative electrode 12. The separator 2 is disposed between the positive electrode 11 and the negative electrode 12.

[0021] When the cylindrical core 100 is unfolded, the width direction of the electrode 1 is the first direction, the length direction of the electrode 1 is the second direction, and a plurality of tabs 3 are spaced apart along the length direction on one side of the electrode 1 in the first direction. A gap 4 is formed between two adjacent tabs 3. The gap 4 extends along the first direction and is open at one end away from the electrode 1. There is a distance h1mm between the end of the gap 4 near the electrode 1 and the electrode 1. The diaphragm 2 extends beyond the electrode 1 along the first direction on the side near the tab 3. The distance between the side of the diaphragm 2 near the tab 3 and the side of the electrode 1 with the tab 3 is h2mm, where h1>h2.

[0022] Specifically, 0.5mm ≤ h1 ≤ 5mm, and the value of h1 can be 0.6mm, 0.7mm, 0.9mm, 1.2mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, or 4.9mm. Therefore, h1 cannot be too small, as this would increase the risk of the diaphragm 2 folding and wrinkling. h1 also cannot be too large, as this would result in a smaller area for electrical connection after the tab 3 folds, leading to a weakened current-carrying capacity.

[0023] It should be noted that when the cylindrical core 100 is not unfolded, the axial direction of the cylindrical core 100 is the first direction.

[0024] In this invention, during the manufacturing of the cylindrical core 100, the positive electrode 11, the separator 2, and the negative electrode 12 are stacked together, with the separator 2 located between the positive electrode 11 and the negative electrode 12. Then, the positive electrode 11, the separator 2, and the negative electrode 12 are wound along a second direction to form the cylindrical core 100. After the electrode 1 and the separator 2 are wound, the tabs 3 on the electrode 1 need to be folded onto the end face of the cylindrical core 100. Among the multiple tabs 3, the gap 4 between two adjacent tabs 3 can be used to position the folding position of the tab 3, facilitating the tab 3 to be folded into place. The area near one end of the electrode 1 begins to fold. At the same time, since h1 > h2, the gap 4 between two adjacent tabs 3 is located in the area where the tabs 3 extend beyond the diaphragm 2. Therefore, when the tabs 3 fold, the diaphragm 2 will not be wrinkled, thus avoiding contact between the positive electrode 11 and the negative electrode 12 and causing a short circuit. Furthermore, the material of the diaphragm 2 is relatively soft. If the diaphragm 2 wrinkles, it will cause uneven surface height, which will result in poor surface height consistency after the tabs 3 are folded, affecting subsequent welding and easily leading to poor welding.

[0025] In some embodiments, the four sides of the diaphragm 2 extend outward beyond the four sides of the electrode 1, thereby allowing the diaphragm 2 to completely cover the electrode 1, thus preventing the positive electrode 11 and the negative electrode 12 from coming into contact and causing a short circuit.

[0026] In this embodiment, 1.05 ≤ h1 / h2 ≤ 1.8. The value of h1 / h2 can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.75 or 1.78.

[0027] If h1 / h2 is too small, it indicates that the distance between the gap 4 between the tabs 3 and the electrode 1 is too small, or that the distance between the side of the diaphragm 2 adjacent to the tab 3 in the first direction and the side of the electrode 1 with the tab 3 is too large. Simultaneously, if the distance between the gap 4 between the tabs 3 and the electrode 1 is too small, the risk of the tabs 3 causing the diaphragm 2 to fold when the tabs 3 are folded increases, increasing the risk of the diaphragm 2 wrinkling. If h1 / h2 is too large, it indicates that the distance between the gap 4 between the tabs 3 and the electrode 1 is too large, or... The diaphragm 2 has a smaller dimension on the side of the electrode 1 adjacent to the tab 3 in the first direction than the side of the electrode 1 where the tab 3 is located. This results in a smaller area of ​​the tab 3 at the end face of the cylindrical core 100 after folding, leading to insufficient electrical connection area for the tab 3. In addition, the smaller dimension of the diaphragm 2 beyond the electrode 1 also increases the risk of contact and short circuit between the positive electrode 11 and the negative electrode 12. Therefore, maintaining 1.05≤h1 / h2≤1.8 is necessary to avoid short circuits in the battery and to prevent wrinkles in the diaphragm 2.

[0028] In this embodiment, in the first direction, the distance between the side of the tab 3 away from the electrode 1 and the electrode 1 is H mm, where 0.1 ≤ (H-h1) / H ≤ 0.5, and 3 mm ≤ H ≤ 9 mm. The value of (H-h1) / H can be 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.47, or 0.49; the value of H can be 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, or 8.5.

[0029] The distance between the side of the tab 3 away from the electrode plate 1 and the electrode plate 1 is H, that is, the dimension of the tab 3 in the first direction is H. The distance between the end of the gap 4 near the electrode plate 1 and the electrode plate 1 is h1. Then H-h1 is the dimension of the gap 4 in the first direction. (H-h1) / H will not be too large. The dimension of the gap 4 in the first direction is smaller than the dimension of the tab 3 in the first direction, so that the root of the tab 3 near the electrode plate 1 is not provided with the gap 4. This can strengthen the structural strength of the root of the tab 3, so that when the tab 3 is folded, it is not easy to cause the root of the tab 3 to fold. Therefore, it will not cause the diaphragm 2 to fold, and will not cause the diaphragm 2 to wrinkle. At the same time, (H-h1) / H will not be too small, so that after the tab 3 is folded, the electrical connection area formed at the end of the cylindrical core 100 meets the welding requirements and ensures the stability of the electrical connection.

[0030] In this embodiment, the electrode tab 3 has a dimension of L mm in the second direction, where 2 ≤ L ≤ 9 and 0.15 ≤ h1 / L ≤ 0.9. The value of h1 / L can be 0.2, 0.22, 0.25, 0.27, 0.3, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.82, 0.85, 0.88, or 0.89. The value of L can be 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, or 8.5 mm.

[0031] When the cylindrical core 100 is unfolded, the dimension of the tab 3 in the second direction is L, that is, the connection length of the tab 3 and the electrode 1 is L. The weldable area and current carrying capacity of the tab 3 after folding are related not only to the dimension of the gap 4 in the first direction, but also to the dimension of the tab 3 in the second direction. If h1 / L is too large, h1 will be too large, or L will be too small, which will result in the tab 3 having a smaller weldable area after folding, which will not meet the current carrying capacity of the battery. If h1 / L is too small, h1 will be too small, or L will be too large, which will result in the tab 3 easily causing the separator 2 to fold and wrinkle after folding, which will also increase the risk of short circuit. Therefore, in order to ensure the stability and current carrying capacity of the battery, 0.15≤h1 / L≤0.9 should be maintained.

[0032] In this embodiment, the diameter of the cylindrical core 100 is D mm, where 0.002 ≤ h1 / D ≤ 0.16. The value of h1 / D can be 0.005, 0.008, 0.01, 0.015, 0.02, 0.025, 0.03, 0.04, 0.06, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.152, 0.155, 0.158, or 0.159.

[0033] Since the larger the diameter D of the cylindrical core 100 is, the more layers the surface electrode 1 is wound up, and the larger the required flow area is. In order to meet the flow capacity, the size of the gap 4 between the tabs 3 in the first direction cannot be too small, so it is necessary to keep 0.002≤h1 / D≤0.16.

[0034] In this embodiment, 0.5≤h1≤5 and / or 0.5≤h2≤4.

[0035] Maintaining a size of 0.5 ≤ h2 ≤ 4 ensures that the separator 2 is not too small beyond the electrode 1, reducing the risk of short circuits in the battery. Conversely, the separator 2 is also not too large beyond the electrode 1, reducing the risk of wrinkles. Since the gap 4 needs to be placed in the area not covered by the separator 2, the size of the separator 2 is not too large, preventing the tab 3 from being too large in the first direction, or the gap 4 from being too small in the first direction, which would affect subsequent welding and current carrying capacity. Simultaneously, maintaining a size of 0.5 ≤ h1 ≤ 5 is crucial. If h1 is too small, it increases the risk of the separator 2 folding and wrinkling. If h1 is too large, after the tab 3 folds, the area for electrical connection of the tab 3 will be smaller, resulting in weaker current carrying capacity.

[0036] like Figure 3As shown, in this embodiment, the positive electrode sheet 11 has a plurality of positive electrode tabs 31 spaced apart along its length on one side in the first direction. A gap 4 is provided between two adjacent positive electrode tabs 31. The distance between the end of the gap 4 near the positive electrode sheet 11 and the positive electrode sheet 11 is h3 mm, where 0.5 ≤ h3 ≤ 5. The value of h3 can be 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.5, 3.8, 4, 4.2, 4.5, 4.6, 4.8, or 4.9.

[0037] That is, by maintaining 0.5≤h3≤5, the positive electrode tab 31 is less likely to cause the diaphragm 2 to wrinkle after being folded, and it also has sufficient current carrying capacity.

[0038] like Figure 4 As shown, in this embodiment, the negative electrode sheet 12 has a plurality of negative electrode tabs 32 spaced apart along its length on one side in the first direction. A gap 4 is provided between two adjacent negative electrode tabs 32. The distance between the end of the gap 4 closest to the negative electrode sheet 12 and the negative electrode sheet 12 is h4 mm, where 0.5 ≤ h4 ≤ 4. The value of h4 can be 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.5, 3.8, or 3.9.

[0039] That is, by maintaining 0.5≤h4≤4, the negative electrode tab 32 is less likely to cause the diaphragm 2 to wrinkle after being folded, and it also has sufficient current carrying capacity.

[0040] In this embodiment, the positive electrode 11 has a plurality of positive electrode tabs 31 spaced apart along its length on one side in the first direction, and a gap 4 is provided between two adjacent positive electrode tabs 31. The negative electrode 12 has a plurality of negative electrode tabs 32 spaced apart along its length on one side in the first direction, and a gap 4 is provided between two adjacent negative electrode tabs 32. The size of the gap 4 between the positive electrode tabs 31 in the first direction is b1 mm, and the size of the gap 4 between the negative electrode tabs 32 in the first direction is b2 mm, wherein -3 ≤ b1 - b2 ≤ 2. The values ​​of b1 - b2 can be -2.5, -2, -1.5, -1, -0.5, 0, 0.5, 1, 1.5, or 1.8.

[0041] Specifically, 3≤b1≤8, 3≤b2≤8, the value of b1 can be 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm and 7.5mm, and the value of b2 can be 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm and 7.5mm.

[0042] That is, by keeping -3≤b1-b2≤2, the difference between the gap 4 of the positive electrode 31 and the gap 4 of the negative electrode 32 is small, so as to control the slit size of the positive electrode 31 and the negative electrode 32. After the positive electrode 31 and the negative electrode 32 are folded, the weldable areas of the positive electrode 31 and the negative electrode 32 at the end face of the cylindrical core 100 are similar, so as to achieve a balance in the current carrying capacity of the positive electrode 31 and the negative electrode 32.

[0043] like Figure 5 As shown, in some embodiments, the tab 3 is trapezoidal, and the two sides of the tab 3 in the first direction are a first connecting portion 33 and a second connecting portion 34, respectively, and the size of the first connecting portion 33 in the second direction is larger than the size of the second connecting portion 34 in the second direction.

[0044] That is, the tab 3 is trapezoidal, and the first connecting part 33 of the tab 3 is connected to the electrode 1, which can increase the structural strength of the root of the tab 3 and make it less likely to cause the diaphragm 2 to wrinkle when the tab 3 is bent.

[0045] In this embodiment, the tab 3 is rectangular and the gap 4 is rectangular, which allows for better control of the size of the gap 4, and the tab 3 has good strength consistency in the lead-out direction.

[0046] In this embodiment, the cylindrical core 100 includes multiple core layers 101. Each core layer 101 includes the electrode sheet 1 and the diaphragm 2 stacked together. Each core layer 101 also includes a plurality of electrode tabs 3 arranged circumferentially. There is a gap 4 between two adjacent electrode tabs 3, and the distance between each gap 4 and the electrode sheet 1 is the same. This facilitates the folding of the electrode tabs 3 on the same core layer 101 and avoids the risk of increased wrinkling of the diaphragm 2 when folding locally.

[0047] In this embodiment, the battery further includes a housing, the cylindrical core 100 is disposed inside the housing, the end of the housing is provided with a terminal post, and the tab 3 is electrically connected to the terminal post or the housing.

[0048] After the tab 3 is folded to the end face of the cylindrical core 100, the tab 3 can be directly electrically connected to the pole post or indirectly electrically connected through the current collector. The tab 3 can also be directly electrically connected to the housing or indirectly electrically connected through the current collector. Specifically, the end of the housing is provided with two pole posts, and the positive tab 31 and the negative tab 32 are electrically connected to the two pole posts respectively. Alternatively, the end of the housing is provided with only one pole post, and one of the positive tab 31 and the negative tab 32 is electrically connected to the pole post, while the other is electrically connected to the housing.

[0049] This utility model also relates to a battery pack, including the battery.

[0050] The battery pack, by employing the aforementioned battery, ensures its performance and stability, and is highly practical.

[0051] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A battery, characterized by, The cylindrical winding core comprises pole pieces, diaphragms and pole tabs, the pole pieces comprise positive pole pieces and negative pole pieces stacked together, the pole tabs comprise positive pole tabs and negative pole tabs, the side edges of the positive pole pieces extend outwardly with the positive pole tabs, the side edges of the negative pole pieces extend outwardly with the negative pole tabs, and the diaphragms are arranged between the positive pole pieces and the negative pole pieces; In the unfolded state of the cylindrical winding core, the width direction of the pole pieces is a first direction, the length direction of the pole pieces is a second direction, a plurality of pole tabs are arranged along the length direction on one side of the pole pieces in the first direction, a gap is formed between adjacent two pole tabs, the gap extends along the first direction, one end of the gap away from the pole pieces is arranged in an open manner, and the distance between the end of the gap close to the pole pieces and the pole pieces is h1 mm.

2. The battery of claim 1, wherein, 1.05≤h1 / h2≤1.

8.

3. The battery of claim 1, wherein, In the first direction, the distance between the side of the pole tab away from the pole pieces and the pole pieces is Hmm, wherein 0.1≤h1 / H≤0.

5.

4. The battery of claim 1, wherein, The size of the pole tab in the second direction is L mm, wherein 0.15≤h1 / L≤0.

9.

5. The battery of claim 1, wherein, 0.5≤h1≤5 and / or 0.5≤h2≤4.

6. The battery of claim 1, wherein, A plurality of the positive pole tabs are arranged along the length direction on one side of the positive pole pieces in the first direction, a gap is arranged between adjacent two positive pole tabs, and the distance between the end of the gap close to the positive pole pieces and the positive pole pieces is h3 mm, wherein 0.5≤h3≤5.

7. The battery of claim 1, wherein, A plurality of the negative pole tabs are arranged along the length direction on one side of the negative pole pieces in the first direction, a gap is arranged between adjacent two negative pole tabs, and the distance between the end of the gap close to the negative pole pieces and the negative pole pieces is h4 mm, wherein 0.5≤h4≤4.

8. The battery of claim 1, wherein, A plurality of the positive pole tabs are arranged along the length direction on one side of the positive pole pieces in the first direction, a gap is arranged between adjacent two positive pole tabs, a plurality of the negative pole tabs are arranged along the length direction on one side of the negative pole pieces in the first direction, a gap is arranged between adjacent two negative pole tabs, the size of the gap between the positive pole tabs in the first direction is b1 mm, and the size of the gap between the negative pole tabs in the first direction is b2 mm, wherein -3≤b1-b2≤2.

9. The battery of claim 1, wherein, The pole tab is trapezoidal, the two sides of the pole tab in the first direction are a first connecting part and a second connecting part respectively, and the size of the first connecting part in the second direction is greater than the size of the second connecting part in the second direction.

10. The battery of claim 1, wherein, The pole tab is a rectangular pole tab, and the gap is a rectangular gap.

11. The battery of claim 1, wherein, The cylindrical winding core comprises a plurality of winding layers, each winding layer comprises the pole pieces and the diaphragms stacked together, each winding layer comprises a plurality of pole tabs arranged along the circumferential direction, a gap is arranged between adjacent two pole tabs, and the distance between each gap and the pole pieces is the same.

12. The battery of claim 1, wherein, Also included is a housing, the cylindrical winding core is arranged in the housing, an end of the housing is provided with a pole column, the tab is electrically connected with the pole column or the housing.

13. A battery pack, characterized by The battery includes any one of claims 1-12.

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