A battery

Abstract

The present application provides a battery, the battery comprising a cell and a pole, the cell comprising a cell body and a tab, the tab comprising a plurality of tab monoliths, each tab monolith comprising two conductive layers and an insulating layer between the two conductive layers, when connecting the tab monoliths of each layer, an indentation is formed on the first end face of the tab away from the pole, the depth of the indentation accounts for a ratio y of the total thickness of the tab, the thickness of the insulating layer of the tab monolith accounts for a ratio h of the thickness of the tab monolith, 1≤h / y≤6. The battery provided by the present application will not lose the tabs in the process of connecting the tab monoliths of each layer and will ensure the connection strength of the tab monoliths of each layer, and will not cause the tab monoliths of each layer to become loose in the process of welding the tabs and the pole, thereby not affecting the welding yield of the tabs and the pole.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery. Background Art

[0002] The battery includes a cell and a pole, the cell includes a cell body and a tab, and the tab is welded to the pole. The tab's multi-layer tab single piece is easy to loosen, affecting the welding yield of the tab and the pole. It is necessary for those skilled in the art to solve the problem of the tab's multi-layer tab single piece loosening. Summary of the invention

[0003] In order to solve the above technical problems, the present application provides a battery, wherein the battery includes a battery cell and a pole, the battery cell includes a battery cell body and a pole lug, the pole lug includes a multi-layer pole lug monolith, each layer of the pole lug monolith includes two conductive layers and an insulating layer located between the two conductive layers, and when connecting the layers of the pole lug monoliths, an indentation is formed on the first end face of the pole lug away from the pole, the depth of the indentation accounts for a ratio y of the total thickness of the pole lug, the thickness of the insulating layer of the pole lug monolith is a ratio h of the thickness of the pole lug monolith, and 1≤h / y≤6.

[0004] In the battery provided in the present application, when connecting the layers of the tab sheets, an indentation is formed on the first end face of the tab away from the pole body, and by controlling the ratio (h / y) of the ratio of the thickness of the insulating layer of the tab sheet to the thickness of the tab sheet to the ratio of the depth of the indentation to the total thickness of the tab within the range of 1-6, damage to the tab is avoided during the process of connecting the layers of the tab sheets, while ensuring the connection strength of the layers of the tab sheets of the tab, so that the layers of the tab sheets are not easy to loosen during the subsequent welding of the tab 2 and the pole, thereby not affecting the welding yield of the tab and the pole. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 A partial top view of an embodiment of a battery provided in the present application;

[0006] Figure 2 It is a side view of the welding of the pole ear and the pole.

[0007] The following are the descriptions of the reference numerals:

[0008] 1 pole body, 2 pole ear, 2a first end face, 21 pole ear single piece, 3 indentation, 4 welding mark, 5 metal sheet, 6 cover plate, 7 pole body, 8 protrusion. DETAILED DESCRIPTION

[0009] The present application provides a battery. In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0010] The battery provided in this application includes a battery cell and a pole, such as Figure 1 As shown, the battery further includes a cover plate 6 and a shell (not shown in the figure), the cover plate 6 and the shell are enclosed to form a receiving cavity, the battery cell is located in the receiving cavity, and the pole is arranged on the cover plate 6.

[0011] like Figure 1 As shown, the battery cell includes a battery cell body 1 and a tab 2. The battery cell body 1 includes a positive electrode sheet and a negative electrode sheet, which are arranged alternately one by one, and a separator is provided between adjacent positive electrode sheets and negative electrode sheets. The tab 2 is led out from at least one end of the battery cell body 1. In the illustrated embodiment, the tabs 2 are led out from both opposite ends of the battery cell body 1.

[0012] like Figure 2 As shown, the tab 2 has a plurality of tab sheets 21, and the plurality of tab sheets 21 are stacked. Each tab sheet 21 includes two conductive layers and an insulating layer between the two conductive layers. Specifically, the conductive layer is generally a metal layer, and illustratively, the conductive layer may be made of copper or aluminum.

[0013] like Figure 2 As shown, when connecting the layers of tab sheets 21, an indentation 3 is formed on the first end surface 2a of the tab 2 away from the pole. Specifically, one indentation 3 may be formed on the first end surface 2a of the tab 2 away from the pole, or multiple indentations 3 may be formed. Specifically, the method of connecting the layers of tab sheets 21 may be ultrasonic welding, hot rolling, hot pressing, etc. After connection, the parts of the tab sheets 21 of each layer corresponding to the indentation 3 are connected into a whole.

[0014] The depth of the indentation 3 accounts for a ratio of y to the total thickness N of the tab 2, and the total thickness N of the tab 2 refers to the sum of the thicknesses of each layer of the tab sheet 21. The thickness of the insulating layer of the tab sheet 21 accounts for a ratio of h to the thickness of the tab sheet 21. 1≤h / y≤6, and illustratively, the value of h / y ​​can be 1, 2, 3, 4, 5, 6. Specifically, the range of y is: 0.05≤y≤0.8. Exemplarily, the value of y can be 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80. Exemplarily, the depth M of the indentation 3 may range from 0.1 mm to 0.5 mm, and the value of M may specifically be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm. Exemplarily, the total thickness of the tab 2 may range from 0.2 mm to 0.6 mm, and specifically may be 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or 0.6 mm.

[0015] The greater the ratio h of the thickness of the insulating layer of the tab sheet 21 to the thickness of the tab sheet 21, the greater the ratio h of the thickness of the tab sheet 21 to the thickness of the tab sheet 21. In order to ensure that the multi-layer tab sheet 21 is fixed more firmly during the process of connecting the tab sheets 21, and to facilitate the subsequent welding of the tab 2 and the pole, it is necessary to increase the ratio of the depth of the indentation 3 to the total thickness of the tab 2, that is, to increase the value of y. However, if the ratio y of the depth of the indentation 3 to the total thickness of the tab 2 is too large, the tab 2 may be damaged during the process of connecting the tab sheets 21. If the ratio y of the depth of the indentation 3 to the total thickness of the tab 2 is too small, the connection strength of the tab sheets 21 is not high, and when subjected to external force (for example, the subsequent welding of the tab 2 and the pole will cause the tab sheet 21 to be subjected to external force), the tab sheets 21 may still be loose. By controlling the value of h / y ​​within the range of 1-6, damage to the tab 2 is avoided during the process of connecting the tab sheets 21 of each layer, while the connection strength of the tab sheets 21 of each layer is guaranteed, so that the tab sheets 21 of each layer will not become loose during the subsequent welding of the tab 2 and the pole, thereby not affecting the welding yield of the pole column and the tab 2.

[0016] In some embodiments, 0.55≤h≤0.8. Exemplarily, the value of h can be 0.55, 0.6, 0.65, 0.7, 0.75, 0.8. h is the ratio of the thickness of the insulating layer of the tab monolith 21 to the thickness of the tab monolith 21. The thickness of the tab monolith 21 is the sum of the thickness of the two conductive layers and the thickness of the insulating layer between the two conductive layers. Specifically, the thickness of the insulating layer of the tab monolith 21 ranges from 2μm to 8μm. Exemplarily, the specific values ​​can be 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm. Specifically, the thickness of the single-layer conductive layer of the tab monolith 21 ranges from 1μm to 2μm. Exemplarily, the specific values ​​can be 1μm, 1.5μm, 2μm.

[0017] When the thickness of the tab single sheet 21 is constant, the greater the ratio h of the thickness of the insulating layer of the tab single sheet 21 to the thickness of the tab single sheet 21, the greater the thickness of the insulating layer of the tab single sheet 21, and the smaller the thickness of the conductive layer of the tab single sheet 21. If h is too large, the thickness of the insulating layer of the tab single sheet 21 will be too large. If the thickness of the insulating layer of the tab single sheet 21 is too large, the portion of the tab single sheet 21 corresponding to the indentation 3 will be compressed to a great extent when connecting the tab single sheets 21 of each layer, causing the edge of the tab single sheet 21 to be lifted, which is not conducive to the life of the tab 2. If h is too large, the thickness of the conductive layer of the tab single sheet 21 will be too small. If the thickness of the conductive layer of the tab single sheet 21 is too small, the battery overcurrent capacity will be insufficient. If h is too small, the thickness of the insulation layer of the tab sheet 21 will be too small. If the thickness of the insulation layer of the tab sheet 21 is too small, the portion of the insulation layer of the tab sheet 21 corresponding to the indentation 3 will be easily crushed when connecting the tab sheets 21. To avoid crushing, the ratio y of the depth of the indentation 3 to the total thickness of the tab 2 can only be controlled to be smaller, which is not conducive to the connection strength of the tab sheets 21. Therefore, h cannot be too large or too small. By controlling h within the range of 0.55-0.8, the overcurrent capacity of the battery can be guaranteed, the connection strength of the tab sheets 21 can be guaranteed, and the life of the tab 2 can be guaranteed.

[0018] In some embodiments, the conductive layer of the tab sheet 21 is made of aluminum. In this case, the range of h is: 0.7≤h≤0.8. Exemplarily, the value of h can be 0.55, 0.6, 0.65, 0.7, 0.75, 0.8. Specifically, in this case, the thickness of the insulating layer of the tab sheet 21 ranges from 6μm to 8μm. Exemplarily, the specific values ​​can be 6μm, 6.5μm, 7μm, 7.5um, 8μm.

[0019] In some embodiments, the conductive layer of the tab monolith 21 is made of copper. In this case, the range of h is 0.55≤h≤0.69. Exemplarily, the value of h can be 0.55, 0.6, 0.625, 0.65, 0.67, 0.69. Specifically, in this case, the thickness of the insulating layer of the tab monolith 21 ranges from 2.5 μm to 4.5 μm. Exemplarily, the specific value can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm.

[0020] In some embodiments, the total area of ​​all indentations 3 on the first end surface 2a is S, 100 mm 2 ≤S≤1000mm 2 , for example, the value of S can be 100 mm 2 , 200mm 2 、300mm 2 , 400mm 2 , 500mm 2、600mm 2 、700mm 2 , 800mm 2 , 900mm 2 , 1000mm 2 In this case, 1.5≤h / y≤6. By way of example, the value of h / y ​​can be 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6.

[0021] After the tab 2 is led out from the battery body 1, it is generally necessary to be bent so that it can be connected to the pole. If the total area S of the indentation 3 is too large, the tab 2 is easily damaged when it is bent. If the total area S of the indentation 3 is too small, the connection strength of each layer of the tab single piece 21 is not high. By controlling the total area S of the indentation 3 to 100mm 2 -1000mm 2 The total area S of the indentation 3 is within 100 mm. 2 -1000mm 2 When it is within the range, the connection strength of each layer of the tab single piece 21 has been guaranteed to a certain extent, so the ratio y of the depth of the indentation 3 to the total thickness of the tab 2 can be appropriately reduced, so the range of h / y ​​can be further limited to the range of 1.5-6.

[0022] In some embodiments, the distance between the edge of the indentation 3 and the edge of the first end face 2a of the pole ear 2 away from the pole body 7 is L, 0.5mm≤L≤5mm, and illustratively, the value of L can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm. In this case, 1≤h / y≤5.6, and illustratively, the value of h / y ​​can be 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.6.

[0023] If the distance L between the edge of the indentation 3 and the edge of the first end face 2a is too small, the first end face 2a of the tab 2 cannot completely cover the pressure head of the connection device (when ultrasonic welding is used, the pressure head of the connection device is the welding head of the ultrasonic welding device) during the process of connecting the tab single sheets 21 of each layer, which affects the life of the connection device. If the distance L between the edge of the indentation 3 and the edge of the first end face 2a is too large, the edge of the tab single sheet 21 is easy to warp during the process of connecting the tab single sheets 21 of each layer. By controlling L within the range of 0.5mm-5mm, it can be ensured that the life of the connection device is not affected, and the edge of the tab single sheet 21 is not easy to warp when connecting the tab single sheets 21 of each layer. When the distance L between the edge of the indentation 3 and the edge of the first end face 2a is within the range of 0.5mm-5mm, the problem of edge warping of the tab single sheet 21 has been suppressed to a certain extent, so the ratio y of the depth of the indentation 3 to the total thickness of the tab 2 can be appropriately increased, so the range of h / y ​​can be further limited to the range of 1-5.6.

[0024] In some embodiments, Figure 2 As shown, the pole includes a pole body 7 and a protrusion 8, the protrusion 8 protrudes from the side of the pole body 7 close to the pole lug 2, and the protrusion 8 passes through each layer of the pole lug single piece 21 of the pole lug 2 and is welded to the pole lug 2. Each layer of the pole lug single piece 21 is pre-connected together before the protrusion 8 passes through. Specifically, one protrusion 8 can be provided on the side of the pole body 7 close to the pole lug 2, or multiple protrusions 8 can be provided. Specifically, the welding method of the pole and the pole lug 2 is preferably resistance welding. The positive projection of the weld mark 4 formed when the protrusion 8 is connected to the pole lug 2 on the first end face 2a of the pole lug 2 is located within the range of the indentation 3. The shortest distance between the edge of the weld mark 4 and the edge of the indentation 3 is x, 0.055≤h / x≤0.8. The value of h / x can specifically be 0.055, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8. Specifically, the range of x is 1 mm-10 mm. Exemplarily, the value of x can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm.

[0025] The greater the ratio h of the thickness of the insulation layer of the tab monolith 21 to the thickness of the tab monolith 21, the more molten material will be melted in the portion of the insulation layer corresponding to the indentation 3 when welding the tab 2 and the pole, and the easier it will be for the molten material to spread to the edge of the insulation layer, causing the edge of the insulation layer to be more easily melted by heat. Once the edge of the insulation layer is also melted by heat, the insulation will fail completely. To avoid the edge of the insulation layer from melting by heat, the greater the total thickness h of the insulation layer of the tab 2, the greater the shortest distance x between the edge of the weld mark 4 and the edge of the indentation 3. However, the shortest distance x between the edge of the weld mark 4 and the edge of the indentation 3 cannot be too large. When the area of ​​the weld mark 4 is constant, if x is too large, it means that the total area S of the indentation 3 is too large. The tab 2 generally needs to be bent after being led out from the battery body 1 so that it can be connected to the pole. If the total area S of the indentation 3 is too large, the tab 2 is easily damaged when it is bent. By controlling h / x within the range of 0.055-0.8, it is possible to prevent the edge of the insulating layer from being melted by heat, resulting in complete insulation failure, and it is also possible to prevent the pole lug 2 from being damaged when the pole lug 2 is bent.

[0026] In some embodiments, the protrusion 8 is a conical protrusion, and the diameter of the protrusion 8 gradually decreases in the direction away from the pole body 7, the end of the protrusion 8 close to the pole body 7 is the large diameter end, and the end away from the pole body 7 is the small diameter end. The conical protrusion is easier to pierce the various layers of the tab single pieces 21 of the pole lug 2. Because the various layers of the tab single pieces 21 of the pole lug 2 are pre-connected with high strength before the protrusion 8 passes through the various layers of the tab single pieces 21 of the pole lug 2, the various layers of the tab single pieces 21 of the pole lug 2 will not be loose when the protrusion 8 passes through the various layers of the tab single pieces 21 of the pole lug 2, so the cone angle of the protrusion 8 can be larger, and a larger cone angle is conducive to the pole mold opening.

[0027] In some embodiments, the maximum diameter of the protrusion 8 is w, 2≤w / x≤20. When the value of the shortest distance x between the edge of the weld mark 4 and the edge of the indentation 3 is constant, the value of w needs to be controlled within a certain range. If w is too large, the protrusion 8 will press against the edge of the tab sheet 21 when passing through each layer of the tab sheet 21, causing the edge of the tab sheet 21 to warp. If w is too small, when welding the tab 2 and the pole, the protrusion 8 cannot withstand the high current and will melt.

[0028] In some embodiments, the battery includes a metal sheet 5, the pole tab 2 is located between the pole body 7 and the metal sheet 5, and the orthographic projection of the weld mark 4 on the first end face 2a of the pole tab 2 is located within the orthographic projection range of the metal sheet 5 on the first end face 2a of the pole tab 2. Specifically, the metal sheet 5 can be made of a material with a lower melting point, such as copper. The metal sheet 5 plays a role of flux, which is more conducive to improving the connection reliability and current capacity of the pole tab 2 and the pole after resistance welding.

[0029] The above specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the present application.

Claims

1. A battery, characterized in that: The battery comprises a cell and a pole, wherein the cell comprises a cell body (1) and a pole tab (2), wherein the pole tab (2) comprises a plurality of pole tab sheets (21), wherein each layer of the pole tab sheet (21) comprises two conductive layers and an insulating layer located between the two conductive layers, and when the layers of the pole tab sheets (21) are connected, an indentation (3) is formed on a first end surface (2a) of the pole tab (2) away from the pole, wherein the depth of the indentation (3) accounts for a ratio y of the total thickness of the pole tab (2), and the thickness of the insulating layer of the pole tab sheet (21) accounts for a ratio h of the thickness of the pole tab sheet (21), and 1≤h / y≤6.

2. The battery according to claim 1, characterized in that 0.55≤h≤0.8。 3. The battery according to claim 2, characterized in that The conductive layer of the tab single piece (21) is made of aluminum, with a value of 0.7≤h≤0.

8.

4. The battery according to claim 2, characterized in that The conductive layer of the tab single piece (21) is made of copper, with a value of 0.55≤h≤0.

69.

5. The battery according to claim 1, characterized in that The total area of ​​all the indentations (3) on the first end surface (2a) is S, 100 mm 2 ≤S≤1000mm 2 , 1.5≤h / y≤6.

6. The battery according to claim 1, characterized in that The distance between the edge of the indentation (3) and the edge of the first end surface (2a) is L, 0.5 mm ≤ L ≤ 5 mm, 1 ≤ h / y ≤ 5.

6.

7. The battery according to any one of claims 1 to 6, characterized in that: The pole comprises a pole body (7) and a protrusion (8), wherein the protrusion (8) protrudes from a side of the pole body (7) close to the pole lug (2), the protrusion (8) passes through each layer of the pole lug single sheet (21) of the pole lug (2) and is welded to the pole lug (2), the orthographic projection of a weld mark (4) formed when the pole lug (2) and the protrusion (8) are welded on the first end face (2a) is located within the range of the indentation (3), and the shortest distance between the edge of the weld mark (4) and the edge of the indentation (3) is x, 0.055≤h / x≤0.

8.

8. The battery according to claim 7, characterized in that The protrusion (8) is a conical protrusion, and the diameter of the protrusion (8) gradually decreases in a direction gradually moving away from the pole body (7).

9. The battery according to claim 8, characterized in that The maximum diameter of the protrusion (8) is w, 2≤w / x≤20.

10. The battery according to claim 7, characterized in that The battery comprises a metal sheet (5), the pole lug (2) is located between the pole body (7) and the metal sheet (5), and the orthographic projection of the weld mark (4) on the first end surface (2a) is located within the orthographic projection range of the metal sheet (5) on the first end surface (2a).

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