Battery and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery and a battery pack, the battery comprises a pole piece, the pole piece comprises a composite current collector, the composite current collector comprises at least one composite material layer made of an insulating material and a conductive layer arranged on at least one side surface of the composite material layer; tabs are formed on the pole pieces; the pole post is provided with a welding surface which is in welding connection with the tab; the welding surface is provided with a puncture part, and the puncture part is suitable for puncturing the composite material layer and is in contact with the conductive layer; the thickness of the composite current collector is D, the thickness of the composite material layer is L, the included angle between the side surface of the puncture part and the welding surface is A, and L / (D.A) is more than or equal to 0.00625 and less than or equal to 0.085. According to the battery provided by the utility model, before the pole and the tab are welded, the pole and the tab are pressed tightly, so that the puncture part can puncture the composite material layer and is in contact with the conductive layer; and therefore, the pole and the tab form a conducting loop, and resistance heat is conveniently generated when current passes through a weldment and a contact part during resistance welding.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery technology field, concretely relates to a battery and battery pack. BACKGROUND

[0002] Resistance welding refers to a method of welding by using resistance heat generated by current through welding pieces and contact points as heat source to locally heat welding pieces and pressurize simultaneously.

[0003] In the related art, some pole pieces adopt a composite current collector form. Since the composite current collector contains a non-conductive composite material layer, the non-conductive property of the composite material layer causes difficulty in welding the composite current collector during resistance welding, gaps exist between the pole pieces, false welding is formed, and the problem of affecting conductivity is caused. SUMMARY

[0004] Therefore, the utility model provides a battery and battery pack to solve the problem of difficulty in resistance welding of the composite current collector.

[0005] In a first aspect, the utility model provides a battery, which comprises:

[0006] The pole piece comprises a composite current collector, the composite current collector contains at least one composite material layer made of insulating material and a conductive layer arranged on at least one side surface of the composite material layer, and the pole piece is formed with a tab.

[0007] The pole column is used for electrically connecting with the tab, the pole column has a welding surface for welding connection with the tab, the welding surface is provided with a puncture part, and the puncture part is adapted to pierce the composite material layer and contact the conductive layer.

[0008] The thickness of the composite current collector is D, the thickness of the composite material layer is L, the included angle between the side surface of the puncture part and the welding surface is A, and the following condition is met: 0.00625≤L / (D·A)≤0.085, unit 1 / °.

[0009] Beneficial effects: the battery provided by the embodiment of the utility model, through setting the puncture part on the welding surface of the pole, the puncture part is suitable for piercing the composite material layer and contacting with the conductive layer, so that the pole and the tab are pressed before the pole and the tab are welded, so that the puncture part can pierce the composite material layer and contact with the conductive layer, and then the pole and the tab form a conduction loop, which is convenient for resistance welding, current passes through the welding piece and the contact to generate resistance heat, realizes local heating of the welding piece, and then realizes the connection of the pole and the tab, solves the problem of difficult resistance welding of the composite current collector. The embodiment limits the range of L / (D·A), the larger L / D is, that is, the larger the proportion of the composite material layer in the composite current collector is, the thicker the composite material layer is, and the more difficult it is to pierce, at this time, the tip of the puncture part needs to be more pointed to smoothly pierce the composite material layer and contact with the conductive layer. On the contrary, the smaller L / D is, that is, the smaller the proportion of the composite material layer in the composite current collector is, the thinner the composite material layer is, and the easier it is to be pierced, at this time, the sharpness of the tip of the puncture part can be appropriately reduced to smoothly pierce the composite material layer and contact with the conductive layer.

[0010] In a second aspect, the utility model also provides a battery pack, include: as above-mentioned battery.

[0011] Because the battery pack includes the battery, has the same effect with the battery, and will not be described here. ACCURATE DRAWINGS

[0012] In order to more clearly illustrate the specific embodiment of the utility model or the technical scheme in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiment or the prior art description, and obviously, the drawings in the following description are some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creating labor.

[0013] Figure 1 It is the cross-sectional view of the pole of the utility model;

[0014] Figure 2 It is the side view of the pole of the utility model;

[0015] Figure 3 It is the schematic diagram of the installation state of the pole and the pole piece of the utility model;

[0016] Figure 4 It is the schematic diagram of the battery of the utility model leading to multiple tabs.

[0017] Explanation of reference signs:

[0018] 1, pole piece;11, conductive layer;12, composite material layer;13, tab;

[0019] 2, pole; 21, welding surface; 22, puncture part. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0024] In the related art, some pole pieces adopt a composite current collector form, the composite current collector includes a composite material layer 12 and a conductive layer 11 arranged on at least one side surface of the composite material layer 12. Since the composite material layer is made of a non-conductive material, when the pole piece containing the composite current collector needs to be welded with the pole, especially when the pole lug extending from the pole piece is welded with the pole, if resistance welding is performed, the non-conductive property of the composite material layer will cause the composite current collector to be difficult to weld, and gaps are easily formed between the pole pieces to form a false weld, thereby easily affecting the conductivity.

[0025] The embodiments of the present application will be described below in conjunction with Figures 1 to 4 ​

[0026] According to the embodiment of the utility model, on the one hand, a battery is provided, comprising:

[0027] The pole piece 1 comprises a composite current collector, and the composite current collector comprises at least one composite material layer 12 made of insulating material and a conductive layer 11 arranged on at least one side surface of the composite material layer 12; the pole piece 1 is formed with a tab 13;

[0028] The pole post 2 is used for electrically connecting with the tab 13, and the pole post 2 has a welding surface 21 welded with the tab 13; the welding surface 21 is provided with a puncture part 22, and the puncture part 22 is adapted to pierce the composite material layer 12 and contact the conductive layer 11;

[0029] The thickness of the composite current collector is D, the thickness of the composite material layer 12 is L, and the included angle between the side surface of the puncture part 22 and the welding surface 21 is A, and the following condition is met: 0.00625≤L / (D·A)≤0.085, unit 1 / °.

[0030] The pole piece 1 of the embodiment comprises a composite current collector, and the composite current collector comprises a composite material layer 12 and a conductive layer 11 arranged on at least one side surface of the composite material layer 12. For example, the conductive layer 11 can be arranged on one side surface of the composite material layer 12, or the conductive layer 11 can be arranged on both side surfaces of the composite material layer 12.

[0031] The pole piece 1 specifically comprises a positive pole piece layer, a negative pole piece layer and a composite current collector located in the middle, the composite current collector separates the positive pole piece layer and the negative pole piece layer, and the electrons in the battery cannot freely pass through, but the ions in the electrolyte can freely pass between the positive and negative electrodes.

[0032] The composite current collector comprises a composite material layer 12, wherein the material of the composite material layer 12 can comprise PP, PET or PI, etc.

[0033] In addition, since the local area of the pole piece 1 forms the tab, in the embodiment, the tab also comprises the composite current collector, and the composite current collector of the tab also comprises the composite material layer 12 and the conductive layer 11 arranged on at least one side surface of the composite material layer 12.

[0034] The embodiment also comprises a pole post 2, and the pole post 2 is used for welding with the tab 13 to realize the conduction connection between the pole group in the battery and the pole post 2, so as to be connected with the external circuit.

[0035] In Figure 1The two side surfaces of the composite material layer 12 are provided with the conductive layer 11, and the composite current collector comprises a first conductive layer, the composite material layer 12 and a second conductive layer which are sequentially stacked; in the welding process, since the composite material layer is made of a non-conductive material, if direct resistance welding is performed, due to the non-conductive characteristic of the composite material layer, the composite current collector is generally difficult to weld, and a gap is easily formed between the pole pieces, thereby affecting the conductivity. In the embodiment, the piercing portion 22 is arranged on the welding surface 21 of the pole 2, and the pole 2 and the tab 13 are pressed before being welded, so that the piercing portion 22 can pierce the composite material layer 12 and contact the conductive layer 11; thereby the pole 2 and the tab 13 form a conduction loop, and when resistance welding is performed, current passes through the welding part and the contact part to generate resistance heat, thereby locally heating the welding part, and the pole 2 and the tab 13 are connected.

[0036] It should be noted that the piercing portion 22 of the embodiment is adapted to at least pierce the composite material layer 12 when piercing the tab 13. For example, when the conductive layer 11 is arranged on one side surface of the composite material layer 12, whether the piercing portion 22 pierces from the side where the composite material layer 12 is arranged or from the side where the conductive layer 11 is arranged, the pole 2 can contact the conductive layer 11 and form a conduction loop for resistance welding. For another example, when the conductive layer 11 is arranged on both side surfaces of the composite material layer 12, whether the piercing portion 22 pierces from the first conductive layer 11 or from the second conductive layer 11, the pole 2 can contact the conductive layer 11 and form a conduction loop for resistance welding after the tab 13 pierces the composite material layer 12.

[0037] The battery provided by the embodiment of the utility model, through setting the piercing portion 22 on the welding surface 21 of the pole 2, the piercing portion 22 is adapted to pierce the composite material layer 12 and contact the conductive layer 11, so that the pole 2 and the tab 13 are pressed before being welded, the piercing portion 22 can pierce the composite material layer 12 and contact the conductive layer 11, the pole 2 and the tab 13 form a conduction loop, when resistance welding is performed, current passes through the welding part and the contact part to generate resistance heat, thereby locally heating the welding part, the pole 2 and the tab 13 are connected, and the problem that the composite current collector is difficult to be welded by resistance welding is solved.

[0038] In combination Figure 1 As shown, the thickness of the composite current collector is D, which refers to the overall thickness of the composite material layer 12 and the conductive layer 11. The thickness of the composite material layer 12 is L, that is, the pole 2 needs to pierce at least the thickness L.

[0039] In some embodiments, the puncture portion 22 can be in the form of a cone, a conical frustum, a triangular conical frustum, or other irregular conical frustum. By adopting a structure in which the area near the welding surface 21 is large and the area far from the welding surface 21 is small, the tab 13 can be easily punctured, and the processing difficulty can be reduced.

[0040] In the embodiment, the angle between the side surface of the puncture portion 22 and the welding surface 21 is A, where A is used to represent the sharpness of the puncture portion 22. When A is smaller, the side surface of the puncture portion 22 is flatter with respect to the welding surface 21, and the tip of the puncture portion 22 far from the welding surface 21 is flatter, and it is less likely to pierce the tab 13. When A is larger, the side surface of the puncture portion 22 is steeper with respect to the welding surface 21, and the tip of the puncture portion 22 far from the welding surface 21 is sharper, and it is more likely to pierce the tab 13.

[0041] In the embodiment, by limiting the range of L / (D·A), when L / D is larger, that is, when the proportion of the composite material layer 12 in the composite current collector is larger, the composite material layer 12 is thicker and more difficult to pierce, and the tip of the puncture portion 22 needs to be sharper to smoothly pierce the composite material layer 12 and contact the conductive layer 11. Conversely, when L / D is smaller, that is, when the proportion of the composite material layer 12 in the composite current collector is smaller, the composite material layer 12 is thinner and more easily pierced, and the sharpness of the tip of the puncture portion 22 can be appropriately reduced to smoothly pierce the composite material layer 12 and contact the conductive layer 11.

[0042] However, the sharpness of the tip of the puncture portion 22 cannot be too flat, otherwise the puncture portion 22 cannot pierce the conductive layer 11. If the tip is too sharp, there is a risk of injuring other parts inside the battery when piercing the tab.

[0043] In some embodiments, in combination with Figure 1 As shown in FIG. 6, the thickness L of the composite material layer 12 satisfies: 0.02 mm≤L≤2.4 mm.

[0044] For example, the thickness L of the composite material layer 12 can be 0.02 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.14 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.24 mm, or other ranges formed by any two of the above values.

[0045] In some embodiments, in combination with Figure 2 As shown in FIG. 7, the angle A between the side surface of the puncture portion 22 and the welding surface 21 satisfies: 10°≤A≤80°.

[0046] For example, the angle A between the side surface of the puncture portion 22 and the welding surface 21 can be 10°, 15°, 20°, 30°, 35°, 45°, 55°, 65°, 70°, 75°, 80°, or any interval formed by any two of the above values.

[0047] For example, the angle A between the side surface of the puncture portion 22 and the welding surface 21 can be measured as follows: the angle A is generally calculated according to the taper, which is equal to the diameter divided by the height. The diameter of the tooth is generally 0.5-3.0, and the height of the tooth is generally 0.5-3.0. That is, A = arctan (tooth height / tooth radius). In this embodiment, A satisfies 10°≤A≤80°.

[0048] In this embodiment, the angle A between the side surface of the puncture portion 22 and the welding surface 21 represents the sharpness of the puncture portion 22. When A is larger, the side surface of the puncture portion 22 is steeper, and the tip of the puncture portion 22 away from the welding surface 21 is sharper, which is easier to pierce the tab 13. However, it also means that the height of the puncture portion 22 is higher, which may cause the puncture portion 22 to be less resistant to bending and even break. When A is smaller, the side surface of the puncture portion 22 is flatter, and the tip of the puncture portion 22 away from the welding surface 21 is flatter, which is less likely to pierce the tab 13. Therefore, the angle A between the side surface of the puncture portion 22 and the welding surface 21 needs to be within a reasonable range.

[0049] In some embodiments, the puncture strength of the composite material layer 12 is less than 190 gf / μm, and satisfies 0.007≤L / (D·A)≤0.085, with the unit being 1 / °.

[0050] The material of the composite material layer 12 can be a polyethylene film, a polypropylene film, or a polyethylene / polypropylene composite film. When the puncture strength of the composite material layer 12 is large, it is more difficult to be punctured, and the angle A between the side surface of the puncture portion 22 and the welding surface 21 needs to be larger so that the tip of the puncture portion 22 is sharper, thereby facilitating the puncture of the composite material layer 12. Therefore, the upper limit of the value of L / (D·A) needs to be smaller.

[0051] In some embodiments, in combination with Figure 4 As shown in FIG. 1, the number of layers of the tab 13 includes one or more layers, the total thickness of the welding position of the tab 13 and the pole 2 is E, and the height of the puncture portion 22 protruding from the welding surface 21 is H, which satisfies E≤H.

[0052] When the number of layers of the tab 13 is multiple, in combination with Figure 4As shown, by stacking the multiple layers of the tab 13 to form a tab group, when the tab 13 is welded with the pole 2, the piercing portion 22 needs to pierce all the multiple layers of the tab 13 to realize the conduction of the resistance welding circuit, so as to smoothly perform the resistance welding. Therefore, the height H of the piercing portion 22 protruding from the welding surface 21 needs to be not less than the total thickness E of the welding position of the tab 13 and the pole 2. Before the pole 2 and the tab 13 are welded, the pole 2 and the tab 13 need to be pressed tightly, and the piercing portion 22 needs to penetrate all the tab 13, so as to ensure the smooth performance of the resistance welding.

[0053] In addition, since the tab is usually formed by mixing multiple layers of single-piece tabs, by using the piercing portion 22 to simultaneously penetrate all the tab 13, the contact resistance of the multiple layers of the tab 13 can be reduced, and the false welding is not easy to occur, so as to optimize the welding firmness of the pole 2 and the tab 13 and reduce the safety hidden danger.

[0054] In some embodiments, the number of layers of the tab 13 includes one or more layers, and the total thickness of the welding position of the tab 13 and the pole 2 is E, which satisfies: 0.00025 mm / °≤E / A≤0.288 mm / °.

[0055] In the embodiment, the range of E satisfies: 0.02 mm≤E≤2.88 mm.

[0056] When the number of layers of the tab 13 is more, the total thickness E of the welding position of the tab 13 and the pole 2 is thicker, and correspondingly, the number of layers of the composite current collector is also more, and a more sharp piercing portion 22 is needed to pierce all the tab 13. Therefore, when the total thickness E is thicker, the included angle A should be larger, so as to meet the piercing requirement. However, the included angle A should not be too large, so as to avoid that the bending resistance of the piercing portion 22 is reduced due to the too high height of the piercing portion 22, and the risk of breaking is reduced.

[0057] In some embodiments, the composite material layer 12 includes multiple layers, which satisfies: 0.08≤L / (D·A)≤0.00625, unit: 1 / °.

[0058] When the composite material layer 12 is multiple layers, it is more difficult to pierce, and a more sharp piercing portion 22 is needed to pierce, that is, the included angle A needs to be larger, so as to pierce the multiple layers of the composite material layer 12.

[0059] In some embodiments, the area of the projection of the region where the single piercing portion 22 contacts the welding surface 21 on the welding surface 21 is S, which satisfies: 0.058 mm 2 ≤S≤6.36 mm 2 .

[0060] The region where the piercing portion 22 contacts the welding surface 21 is the root of the connection of the piercing portion 22 and the welding surface 21.

[0061] When the area S of the projection of the welding surface 21 is too small, the overcurrent area is insufficient, and the conductive requirement of the pole 2 cannot be met. When the area S of the projection of the welding surface 21 is too large, the resistance welding process cannot quickly melt the composite material layer 12, thereby reducing the welding efficiency and easily causing false welding.

[0062] In some embodiments, the composite current collector comprises a plurality of layers of the composite material layer 12, and each two adjacent active material layers are provided with at least one layer of the composite material layer 12, and satisfies 0.008≤L / (D·A)≤0.085, unit 1 / °. Figure 2 As shown, the number of the piercing parts 22 is multiple, and satisfies 0.007≤L / (D·A)≤0.08, unit 1 / °.

[0063] By arranging multiple piercing parts 22, the contact area between the pole 2 and the conductive layer 11 of the pole piece 1 can be increased, and the overcurrent conduction capacity can be improved.

[0064] In some embodiments, the composite current collector comprises a plurality of layers of the composite material layer 12, and each two adjacent active material layers are provided with at least one layer of the composite material layer 12, and satisfies 0.008≤L / (D·A)≤0.085, unit 1 / °.

[0065] The active material layer in this embodiment refers to the positive pole piece layer or the negative pole piece layer.

[0066] According to the embodiments of the utility model, on the other hand, a battery pack is also provided, which comprises the battery as described above.

[0067] Obviously, the above embodiments are only examples for clearly illustrating, and are not limited to the embodiments. Although the embodiments of the utility model are described in combination with the drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the utility model, and such modifications and variations all fall within the scope defined by the utility model.

Claims

1. A battery, characterized by, The application relates to a battery, comprising: a pole piece (1) comprising a composite current collector, the composite current collector comprising at least one composite material layer (12) made of insulating material and a conductive layer (11) arranged on at least one side surface of the composite material layer (12); the pole piece (1) is formed with a tab (13); a pole column (2) for electrically connecting with the tab (13), the pole column (2) having a welding surface (21) welded with the tab (13); the welding surface (21) is provided with a piercing part (22) adapted to pierce the composite material layer (12) and contact the conductive layer (11); the thickness of the composite current collector is D, the thickness of the composite material layer (12) is L, and the included angle between the side surface of the piercing part (22) and the welding surface (21) is A, and the following condition is met: 0.00625 <= L / (D*A) <= 0.085, unit: 1 / degree.

2. The battery of claim 1, wherein, The thickness L of the composite material layer (12) meets the following condition: 0.02 mm <= L <= 2.4 mm.

3. The battery of claim 1, wherein, The included angle A between the side surface of the piercing part (22) and the welding surface (21) meets the following condition: 10 <= A <= 80.

4. The battery of claim 1, wherein, The thickness D of the composite current collector ranges from 0.04 mm to 3.2 mm.

5. The battery of claim 1, wherein, The piercing strength of the composite material layer (12) is less than 190 gf / mu m, and L / (D*A) meets the following condition: 0.007 <= L / (D*A) <= 0.085, unit: 1 / degree.

6. The battery of claim 1, wherein, The tab (13) comprises one or more layers, the total thickness of the tab (13) at the welding position with the pole column (2) is E, the height of the piercing part (22) protruding from the welding surface (21) is H, and the following condition is met: E <= H.

7. The battery of claim 1, wherein, The tab (13) comprises one or more layers, the total thickness of the tab (13) at the welding position with the pole column (2) is E, and the following condition is met: 0.00025 mm / degree <= E / A <= 0.288 mm / degree.

8. The battery of claim 1, wherein, The composite material layer (12) comprises multiple layers, and the following condition is met: 0.08 <= L / (D*A) <= 0.00625, unit: 1 / degree.

9. The battery of claim 1, wherein, The area of the projection of the welding surface (21) in the region where the single piercing portion (22) is in contact with the welding surface (21) is S, satisfying: 0.058 mm 2 ≤ S ≤ 6.36 mm 2 .

10. The battery according to any one of claims 1 to 8, characterized in that, The number of the piercing parts (22) is multiple, and the following condition is met: 0.007 <= L / (D*A) <= 0.08, unit: 1 / degree.

11. The battery according to any one of claims 1 to 8, characterized in that, The composite current collector comprises multiple composite material layers (12), at least one composite material layer (12) is arranged between every two adjacent active material layers, and the following condition is met: 0.008 <= L / (D*A) <= 0.085, unit: 1 / degree.

12. A battery pack, characterized by, The application further relates to a battery comprising any one of the batteries as claimed in claims 1 to 11.

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