Battery and battery module

Abstract

The invention relates to the technical field of batteries, and discloses a battery and a battery module. The battery comprises a current collecting disc, a shell and a roll core arranged in the shell, tabs are arranged at the two ends of the roll core respectively, one surface of the current collecting disc is welded with the tabs in a one-to-one correspondence mode, and a welding line track is correspondingly formed on the other surface of the current collecting disc; the welding line track is in a wave shape, and the wave crests and the wave troughs of the wave shape are intermittent welding tracks. According to the invention, the welding line track for welding the current collecting plate and the tab is set to be wave-shaped, so that the welding area between the tab and the current collecting plate can be increased, and the internal resistance of the battery is reduced. Meanwhile, intermittent welding tracks are arranged at the wave crests and the wave troughs of the wave shape, so that the diaphragm can be prevented from being damaged due to energy accumulation during welding, and the performance of the battery is effectively ensured.

Description

Technical Field

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

[0002] Cylindrical lithium batteries are widely used in various fields. They usually include a core, and the two ends of the core are connected to the collector plate through the tabs, and the tabs and the collector plate are connected by welding. Different welding methods and welding trajectories affect the resistance of the collector plate and the core, which has a great impact on the internal resistance of the battery.

[0003] However, in the current welding method, the welding area between the tab and the collector plate is usually small, which leads to a large resistance between the collector plate and the winding core, affecting the internal resistance of the battery. In addition, the existing welding method is continuous welding at the corner of the weld, which will cause energy accumulation and damage the diaphragm, affecting the performance of the battery. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a battery and a battery module, which increases the welding area between the pole ear and the collecting plate, reduces the internal resistance of the battery, avoids damage to the diaphragm during welding, and ensures battery performance.

[0005] The technical solution adopted by this application to solve its technical problem is:

[0006] A battery comprises a current collecting plate, a shell and a winding core arranged inside the shell, wherein two ends of the winding core are respectively provided with pole ears, one surface of the current collecting plate is welded to the pole ears in a one-to-one correspondence, and another surface of the current collecting plate is correspondingly formed with a welding line track;

[0007] The welding line track is wavy, and the crests and troughs of the wavy shape are intermittent welding tracks.

[0008] Preferably, the current collecting disc comprises a negative current collecting disc, the negative current collecting disc is circular, a plurality of first welding wire tracks are evenly distributed on the surface of the negative current collecting disc around the center thereof, and the first welding wire tracks themselves extend in the radial direction of the negative current collecting disc.

[0009] Preferably, the current collecting plate also includes a positive current collecting plate, which is a circle with a notch, and the notch is used for the pole to pass through. The surface of the positive current collecting plate is evenly distributed with multiple first down liquid holes and one second down liquid hole around its center, and the second down liquid hole is arranged close to the notch, and the first welding wire track is arranged between two adjacent first down liquid holes, and the second welding wire track is arranged between the first down liquid hole and the second down liquid hole, and the first welding wire track and the second welding wire track themselves extend along the radial direction of the positive current collecting plate.

[0010] Preferably, the first welding line track includes a first track line and a second track line connected to each other, and the first track line is arranged close to the center of the collecting plate;

[0011] The first track line is composed of a plurality of first track units, the second track line is composed of a plurality of second track units, and the wave height of the second track units is greater than the wave height of the first track units.

[0012] Preferably, the radius of the positive current collector disc and the negative current collector disc is the same, and the radius is R1; the center of the positive current collector disc and the negative current collector disc is provided with a center hole for a needle puncture test, and the radius of the center hole is R2; the radius of the first lower liquid hole is R3;

[0013] The first track unit includes two first welding lines, one end of the two first welding lines intersects at a first intersection, and the wave height of the first track unit is H1, wherein: ;

[0014] The value range of R1 is 8-24 mm, the value range of R2 is 1.5-4 mm, the value range of R3 is 1.4-3 mm, the radius range of the second lower liquid hole is 1-2.5 mm, and the thickness of the collecting plate is 0.1-0.6 mm.

[0015] Preferably, the first welding line includes a first main body and a first connecting portion, the first connecting portions of two first welding lines intersect at the first intersection, the first connecting portion is an intermittent welding track, and the length of the first connecting portion is L1, and the value range of L1 is 1.5 to 3.6 mm;

[0016] The included angle between the two first main body parts is α, and the value range of α is 20-30°.

[0017] Preferably, the radius of the positive electrode current collecting disc and the radius of the negative electrode current collecting disc are the same, and the radius is R1; the radius of the first lower liquid hole is R3;

[0018] The second track unit includes two second welding lines, one end of the two second welding lines intersects at a second intersection, and the wave height of the second track unit is H2, wherein: ;

[0019] The value range of R1 is 8-24 mm, the value range of R3 is 1.4-3 mm, and the thickness of the collecting plate is 0.1-0.6 mm.

[0020] Preferably, the second welding line includes a second main body and a second connecting portion, the second connecting portions of two second welding lines intersect at the second intersection, the second connecting portion is an intermittent welding track, and the length of the second connecting portion is L2, and the value range of L2 is 1.5 to 3.6 mm;

[0021] The included angle between the two second main body parts is β, and the value range of β is 15-30°.

[0022] Preferably, the second wire bonding track is composed of a plurality of the first track units.

[0023] A battery module comprises the above-mentioned battery.

[0024] Compared with the prior art, the battery and battery module of the embodiment of the present application have the following beneficial effects: by setting the welding line track of the current collector plate and the pole lug to be wavy, the welding area between the pole lug and the current collector plate can be increased, and the internal resistance of the battery can be reduced. At the same time, by setting the wave crests and troughs of the wave shape to intermittent welding tracks, that is, the corners of the welding line track are intermittently welded, it is possible to avoid energy accumulation during welding that causes damage to the diaphragm, thereby effectively ensuring the performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the positive electrode current collecting plate welding line track of the present application.

[0026] Figure 2 This is a schematic structural diagram of the welding line track of the negative electrode current collector of the present application.

[0027] Figure 3 This is a schematic structural diagram of the first welding wire track of the present application.

[0028] Figure 4 This is a schematic structural diagram of the first track unit of the present application.

[0029] Figure 5 This is a schematic diagram of the structure of the second track unit of the present application.

[0030] Among them: 1-positive electrode current collecting plate, 11-notch, 12-center hole, 13-first lower liquid hole, 14-second lower liquid hole, 15-side plane, 2-negative electrode current collecting plate, 3-first welding line track, 31-first track line, 311-first track unit, 3111-first welding line, 31111-first main body, 31112-first connecting part, 3112-first intersection, 32-second track line, 321-second track unit, 3211-second welding line, 32111-second main body, 32112-second connecting part, 3212-second intersection, 4-second welding line track, 5-boss. DETAILED DESCRIPTION

[0031] In this application, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0033] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0034] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] like Figure 1-2 As shown, a battery of a preferred embodiment of the present application includes a current collector, a shell and a winding core arranged inside the shell, and pole ears are respectively provided at both ends of the winding core, and one surface of the current collector corresponds to the pole ears one by one, and is laser welded, and the width of the weld is 0.2-0.4mm. Specifically, the current collector includes a positive current collector 1 and a negative current collector 2, and the negative current collector 2 is circular, one surface of which is connected to the negative ear, and a circular boss 5 is provided at the center of the other surface, and the radius of the boss 5 is approximately 0.2 times the radius of the negative current collector 2, and the height of the boss 5 is 0.1-0.3mm, such as 0.15mm, 0.2mm, 0.25mm, etc.

[0036] The shell has an opening, the winding core is inserted into the shell through the opening, and the boss 5 is connected to the bottom wall of the shell so that the shell is negatively charged. The opening is covered with a cover body, the positive electrode current collecting disc 1 is arranged between the cover body and the positive electrode ear, the cover body is provided with a liquid injection hole, and the positive electrode current collecting disc 1 is provided with a lower liquid hole connected to the liquid injection hole.

[0037] A welding line track is correspondingly formed on the other surface of the current collecting plate; the welding line track is wavy, and the crests and troughs of the wavy shape are intermittent welding tracks.

[0038] Based on the battery with the above technical features, by setting the welding line track of the current collector and the pole ear to be wavy, the welding area between the pole ear and the current collector can be increased, and the internal resistance of the battery can be reduced. At the same time, by setting the wave crest and trough of the wave shape to intermittent welding tracks, that is, the corners of the welding line track are intermittently welded, it is possible to avoid energy accumulation during welding that causes damage to the diaphragm, thereby effectively ensuring the performance of the battery.

[0039] In addition, in order to further ensure the performance of the battery and avoid short circuit caused by diaphragm damage, the winding core uses a 1.5-3.5um alumina coated diaphragm. At the same time, the collecting plate includes a welding portion and an abutting portion, the welding portion is connected to the pole ear, and the abutting portion is connected to the winding core. The surface where the abutting portion is connected to the winding core is coated with a 50-150um alumina layer, such as 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, etc., or a value or any range between any two of the above values, to prevent the heat generated by welding from causing the diaphragm to be damaged and causing a short circuit. The following is a specific example and a comparative example to illustrate the effect of adding an alumina layer.

[0040] Embodiment 1

[0041] The collector plate is welded using the designed positive and negative electrode welding method, using a 1.5-3.5um alumina coated diaphragm and a single-sided 50-150um alumina layer collector plate. After welding, the diaphragm is not damaged and the internal resistance is small;

[0042] Comparative Example 1

[0043] Conventional pulse spot welding is used, 4 welding positions are connected using 8 welding points, using base film and uncoated busbar (other specifications are the same). After welding, the diaphragm is prone to damage (pits or shrinkage) and the internal resistance value is large.

[0044] Battery Cell Diaphragm appearance Internal resistance Embodiment 1 20 / 20 no damage no shrinkage 2.0 Comparative Example 1 3 / 20 Damage / Shrinkage 2.3 (increase by 15%)

[0045] It can be seen from the above table that after the current collecting plate was coated with the aluminum oxide layer, the appearance of the diaphragm was not damaged and the internal resistance remained unchanged; without the aluminum oxide layer, three of the twenty diaphragms were damaged in appearance and the internal resistance increased by 15%.

[0046] In this embodiment, the welding wire track includes a first welding wire track 3 and a second welding wire track 4. Specifically, a plurality of first welding wire tracks 3 are evenly distributed in a ring array around the center of the surface of the negative electrode current collector 2, and the first welding wire track 3 itself extends along the radial direction of the negative electrode current collector 2. Preferably, four first welding wire tracks 3 are provided on the negative electrode current collector 2, and the center lines of any two adjacent first welding wire tracks 3 are perpendicular.

[0047] The positive electrode current collector 1 is a circle with a notch 11, and the notch 11 is used for the pole to pass through. The notch 11 can be of different shapes, preferably a semi-elliptical shape, so as to divide the outer side of the positive electrode current collector 1 into an arc surface and a side plane 15. The surface of the positive electrode current collector 1 is evenly distributed with a plurality of first liquid holes 13 and a second liquid hole 14 in a circular array around its center. The setting of multiple liquid holes can increase the penetration efficiency of the electrolyte. Preferably, there are three first liquid holes 13, and the connecting line of the centers of each liquid hole forms a square. The second liquid hole 14 is arranged close to the notch 11, and the radius of the second liquid hole 14 is smaller than the radius of the first liquid hole 13, so as to ensure the setting of the second liquid hole 14. Specifically, the radius of the first liquid hole 13 is 1.4-3mm, such as 1.5mm, 1.8mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.8mm, etc. The radius of the second lower liquid hole 14 is 1-2.5 mm, such as 1.1 mm, 1.2 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, etc.

[0048] The first welding line track 3 is provided between two adjacent first lower liquid holes 13, and the second welding line track 4 is provided between the first lower liquid hole 13 and the second lower liquid hole 14, that is, there are two first welding line tracks 3 and two second welding line tracks 4 on the positive electrode current collecting disc 1. The first welding line track 3 and the second welding line track 4 themselves extend along the radial direction of the positive electrode current collecting disc 1.

[0049] like Figure 3-5As shown, the first welding wire track 3 includes a first track line 31 and a second track line 32 connected to each other, and the first track line 31 is arranged close to the center of the collector plate. The first track line 31 is composed of a plurality of first track units 311, and the second track line 32 is composed of a plurality of second track units 321, and the wave height of the second track unit 321 is greater than the wave height of the first track unit 311. That is, the welding track length of the inner circle from the center of the circle is short, and the distance from the center of the circle is shorter than that of the outer circle. Due to the increase in the curvature of the winding core, the area of ​​the outer circle pole piece is larger, so that the welding track length can be increased and the track angle can be reduced, and the welding area can be increased, so that the collector plate and the winding core are better connected, the connection area is wider and the resistance is smaller.

[0050] When setting, the first track unit 311 and the second track unit 321 are determined based on the size of the lower liquid hole, the size of the central hole 12 for the needle puncture test set in the center of the collecting plate, and the size of the collecting plate itself. Specifically:

[0051] The positive electrode current collecting disc 1 and the negative electrode current collecting disc 2 have the same radius, which is R1; the centers of the positive electrode current collecting disc 1 and the negative electrode current collecting disc 2 are both provided with a center hole 12 for a needle puncture test, and the radius of the center hole 12 is R2; the radius of the first lower liquid hole 13 is R3.

[0052] The first track unit 311 includes two first welding lines 3111. One end of the two first welding lines 3111 intersects at a first intersection 3112. The wave height of the first track unit 311 is H1. The second track unit 321 includes two second welding lines 3211, one end of the two second welding lines 3211 intersects at a second intersection 3212, and the wave height of the second track unit 321 is H2. .

[0053] At the same time, the value range of R1 is 8 to 24 mm, such as 9 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 21 mm, 22 mm, 23 mm, etc., or a value or any range between any two of the above values. The value range of R2 is 1.5 to 4 mm, such as 1.6 mm, 1.8 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 3.6 mm, 3.8 mm, etc., or a value or any range between any two of the above values. The value range of R3 is 1.4 to 3 mm, such as 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.5 mm, 2.6 mm, 2.8 mm, 2.9 mm, etc., or a value or any range between any two of the above values. The radius of the second lower liquid hole ranges from 1 to 2.5 mm, such as 1.1 mm, 1.2 mm, 1.3 mm, 1.5 mm, 1.8 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, etc., or a value or any range between any two of the above values.

[0054] In addition, the line connecting the center of the center hole 12 of the positive electrode current collecting disc 1 and the center of the second lower liquid hole 14 is perpendicular to the side plane 15 of the positive electrode current collecting disc 1, and the distance between the center of the center hole 12 and the perpendicular line of the side plane 15 is E, E=0.75R1+R2, so that the size of the notch 11 can be determined. At the same time, the centers of the second lower liquid hole 14, the center hole 12, and the first lower liquid hole 13 opposite to the second lower liquid hole 14 are on the same straight line, and the straight line is perpendicular to the side plane 15, so that the position of each lower liquid hole can be determined.

[0055] In this embodiment, the first welding line 3111 and the second welding line 3211 both include a main body and a connecting portion. Specifically:

[0056] The first welding line 3111 includes a first main body 31111 and a first connecting portion 31112. The first connecting portions 31111 of the two first welding lines 3111 intersect at the first intersection 3112. The first connecting portion 31112 is an intermittent welding track, and the length of the first connecting portion 31112 is L1. The value range of L1 is 1.5 to 3.6 mm, such as 1.6 mm, 1.8 mm, 2 mm, 2.5 mm, 3 mm, 3.1 mm, 3.2 mm, 3.5 mm, etc., or a value or any range between any two of the above values. The first connecting portion 31112 can be an arc, and the value of L1 is the length of the line connecting the two ends of the arc; the first connecting portion 31112 can also be a straight line.

[0057] The angle between the two first main bodies 31111 of the first welding line 3111 is α, and the value range of α is 20-30°, such as 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, etc.

[0058] The second welding line 3211 includes a second main body 32111 and a second connecting portion 32112. The second connecting portions 32112 of the two second welding lines 3211 intersect at the second intersection 3212. The second connecting portion 32112 is an intermittent welding track, and the length of the second connecting portion 32112 is L2. The value range of L2 is 1.5 to 3.6 mm, such as 1.6 mm, 1.8 mm, 2 mm, 2.5 mm, 3 mm, 3.1 mm, 3.2 mm, 3.5 mm, etc., or a value or any range between any two of the above values. The second connecting portion 32112 can be an arc, and the value of L2 is the length of the line connecting the two ends of the arc; the second connecting portion 32112 can also be a straight line.

[0059] The angle between the two second main body parts 32111 of the second welding line 3211 is β, and the value range of β is 15-30°, such as 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, etc.

[0060] In this embodiment, the second wire welding track 4 is composed of a plurality of the first track units 311 , and the first track unit 311 is the above-mentioned first track unit 311 , which will not be described in detail herein.

[0061] In this embodiment, the thickness of the collecting plate is 0.1-0.6 mm, such as 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc. If possible, the collecting plate can be set to be as thick as possible, so as to better reduce its own resistance and ensure the performance of the battery.

[0062] In order to solve the above technical problems, the present application also provides a battery module, including a conductive connector and a plurality of the above batteries, two adjacent batteries are connected via the conductive connector, and series-parallel connection between the battery cells is formed by connecting the conductive connectors.

[0063] The battery module of the present application can increase the welding area between the pole ear and the current collecting plate, reduce the internal resistance of the battery, avoid damage to the diaphragm during welding, and ensure the performance of the battery module.

[0064] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present application. These improvements and substitutions should also be regarded as the scope of protection of the present application.

Claims

1. A battery, characterized in that: It comprises a current collecting plate, a shell and a winding core arranged inside the shell, wherein two ends of the winding core are respectively provided with pole ears, one surface of the current collecting plate is welded with the pole ears in a one-to-one correspondence, and a welding line track is formed correspondingly on the other surface of the current collecting plate; The welding line track is wavy, and the crests and troughs of the wavy shape are intermittent welding tracks.

2. The battery according to claim 1, characterized in that: The current collecting disc comprises a negative current collecting disc, which is circular, and has a plurality of first welding wire tracks evenly distributed on the surface of the negative current collecting disc around the center thereof, and the first welding wire tracks themselves extend in the radial direction of the negative current collecting disc.

3. The battery according to claim 2, characterized in that: The current collecting plate also includes a positive current collecting plate, which is a circle with a notch, and the notch is used for the pole to pass through. The surface of the positive current collecting plate is evenly distributed with multiple first lower liquid holes and one second lower liquid hole around its center, and the second lower liquid hole is arranged close to the notch, and the first welding wire track is arranged between two adjacent first lower liquid holes, and the second welding wire track is arranged between the first lower liquid hole and the second lower liquid hole, and the first welding wire track and the second welding wire track themselves extend along the radial direction of the positive current collecting plate.

4. The battery according to claim 3, characterized in that: The first welding line track includes a first track line and a second track line connected to each other, and the first track line is arranged close to the center of the collecting plate; The first track line is composed of a plurality of first track units, the second track line is composed of a plurality of second track units, and the wave height of the second track units is greater than the wave height of the first track units.

5. The battery according to claim 4, characterized in that: The positive electrode current collecting disc and the negative electrode current collecting disc have the same radius, and the radius is R1; the positive electrode current collecting disc and the negative electrode current collecting disc are both provided with a central hole for a needle puncture test in the center, and the radius of the central hole is R2; the radius of the first lower liquid hole is R3; The first track unit includes two first welding lines, one end of the two first welding lines intersects at a first intersection, and the wave height of the first track unit is H1, where: H1 = √2 (R1-R2-R3) 2 -1; The value range of R1 is 8-24 mm, the value range of R2 is 1.5-4 mm, the value range of R3 is 1.4-3 mm, the radius range of the second lower liquid hole is 1-2.5 mm, and the thickness of the collecting plate is 0.1-0.6 mm.

6. The battery according to claim 5, characterized in that: The first welding line includes a first main body and a first connecting portion, the first connecting portions of the two first welding lines intersect at the first intersection, the first connecting portion is an intermittent welding track, and the length of the first connecting portion is L1, and the value range of L1 is 1.5 to 3.6 mm; The included angle between the two first main body parts is α, and the value range of α is 20-30°.

7. The battery according to claim 4, characterized in that: The radius of the positive electrode current collecting disc and the negative electrode current collecting disc is the same, and the radius is R1; the radius of the first lower liquid hole is R3; The second track unit includes two second welding lines, one end of the two second welding lines intersects at a second intersection, and the wave height of the second track unit is H2, where: H2 = √2 (R1-R3) 2 -1; The value range of R1 is 8-24 mm, the value range of R3 is 1.4-3 mm, and the thickness of the collecting plate is 0.1-0.6 mm.

8. The battery according to claim 7, characterized in that: The second welding line includes a second main body and a second connecting portion, the second connecting portions of the two second welding lines intersect at the second intersection, the second connecting portion is an intermittent welding track, and the length of the second connecting portion is L2, and the value range of L2 is 1.5 to 3.6 mm; The included angle between the two second main body parts is β, and the value range of β is 15-30°.

9. The battery according to claim 4, characterized in that: The second wire bonding track is composed of a plurality of the first track units.

10. A battery module, characterized in that: Comprising a battery as claimed in any one of claims 1 to 9.

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