Battery and battery module

Abstract

The application relates to the battery technical field 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, two ends of the roll core are respectively provided with tab terminals, one surface of the current collecting disc is welded in one-to-one correspondence with the tab terminals, and the other surface of the current collecting disc is correspondingly formed with a welding track; the welding track is in a wave shape, and the wave peaks and wave troughs of the wave shape are all discontinuous welding tracks. According to the application, the welding track for welding the current collecting disc and the tab terminals is in a wave shape, so that the welding area between the tab terminals and the current collecting disc can be increased, and the battery internal resistance can be reduced. Meanwhile, the wave peaks and wave troughs of the wave shape are arranged as discontinuous welding tracks, so that the damage of the diaphragm caused by energy accumulation during welding can be avoided, and the performance of the battery can be effectively ensured.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery and a battery module. Background Technology

[0002] Cylindrical lithium batteries are widely used in various fields. They typically consist of a core, with both ends connected to a current collector via tabs, which are then welded together. Different welding methods and welding trajectories affect the resistance of the current collector and the core, thus significantly influencing the battery's internal resistance.

[0003] However, current welding methods typically result in a small welding area between the tabs and the current collector, leading to higher resistance between the current collector and the winding core, which affects the battery's internal resistance. Furthermore, existing welding methods involve continuous welding at weld corners, which can cause energy accumulation and damage the separator, impacting battery performance. Summary of the Invention

[0004] To address the aforementioned technical issues, this application provides a battery and battery module that increases the welding area between the tabs and the current collector, reduces the battery's internal resistance, avoids damage to the separator during welding, and ensures battery performance.

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

[0006] A battery includes a current collector, a housing, and a winding core disposed inside the housing. The winding core has tabs at both ends. One surface of the current collector is welded to the tabs in a corresponding manner, and the other surface of the current collector has a corresponding welding line trace.

[0007] The welding line trajectory is wavy, and the peaks and troughs of the wavy shape are both discontinuous welding trajectories.

[0008] Preferably, the current collector includes a negative current collector, which is circular. The surface of the negative current collector has a plurality of first bonding wire tracks evenly distributed around its center, and the first bonding wire tracks themselves extend radially along the negative current collector.

[0009] Preferably, the current collector further includes a positive current collector, which is a circle with a notch for the electrode post to pass through. The surface of the positive current collector is evenly distributed with a plurality of first liquid discharge holes and a second liquid discharge hole around its center, and the second liquid discharge hole is located close to the notch. A first bonding wire trajectory is provided between two adjacent first liquid discharge holes, and a second bonding wire trajectory is provided between the first liquid discharge hole and the second liquid discharge hole. Both the first bonding wire trajectory and the second bonding wire trajectory extend radially along the positive current collector.

[0010] Preferably, the first bonding wire trajectory includes a first trajectory line and a second trajectory line connected together, and the first trajectory line is set close to the center of the collector plate;

[0011] The first trajectory line is composed of multiple first trajectory units, the second trajectory line is composed of multiple second trajectory units, and the wave height of the second trajectory unit is greater than the wave height of the first trajectory unit.

[0012] Preferably, the positive electrode current collector and the negative electrode current collector have the same radius, and the radius is R1; the center of the positive electrode current collector and the negative electrode current collector are provided with a central hole for needle puncture test, and the radius of the central hole is R2; the radius of the first liquid outlet is R3.

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

[0014] Furthermore, 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 of the second liquid outlet 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 part, the first connecting parts of the two first welding lines intersect at the first intersection point, the first connecting part is an intermittent welding trajectory, and the length of the first connecting part is L1, the value of L1 is in the range of 1.5 to 3.6 mm;

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

[0017] Preferably, the positive electrode current collector and the negative electrode current collector have the same radius, and the radius is R1; the radius of the first liquid outlet is R3.

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

[0019] Furthermore, the value range of R1 is 8 to 24 mm, the value range of R3 is 1.4 to 3 mm, and the thickness of the collector plate is 0.1 to 0.6 mm.

[0020] Preferably, the second welding line includes a second main body and a second connecting part, the second connecting parts of the two second welding lines intersect at the second intersection point, the second connecting part is an intermittent welding trajectory, and the length of the second connecting part is L2, the value 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 of β ranges from 15 to 30°.

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

[0023] A battery module comprising the aforementioned battery.

[0024] The battery and battery module of this application embodiment have the following advantages compared with the prior art: by setting the welding line trajectory of the current collector and the electrode tab to a wavy shape, the welding area between the electrode tab and the current collector can be increased, thereby reducing the internal resistance of the battery. At the same time, by setting the peaks and troughs of the wavy shape to be discontinuous welding trajectories, that is, the corners of the welding line trajectory are discontinuous welding, the energy accumulation during welding that could damage the separator can be avoided, thereby effectively ensuring the performance of the battery. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the bonding wire trajectory of the positive current collector in this application.

[0026] Figure 2 This is a schematic diagram of the negative electrode current collector welding wire trajectory of this application.

[0027] Figure 3 This is a schematic diagram of the structure of the first bonding wire trajectory in this application.

[0028] Figure 4 This is a schematic diagram of the structure of the first trajectory unit of this application.

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

[0030] Wherein: 1-Positive electrode current collector, 11-Notch, 12-Center hole, 13-First liquid discharge hole, 14-Second liquid discharge hole, 15-Side plane, 2-Negative electrode current collector, 3-First welding line trajectory, 31-First trajectory line, 311-First trajectory unit, 3111-First welding line, 31111-First main body, 31112-First connecting part, 3112-First intersection point, 32-Second trajectory line, 321-Second trajectory unit, 3211-Second welding line, 32111-Second main body, 32112-Second connecting part, 3212-Second intersection point, 4-Second welding line trajectory, 5-Boss. Detailed Implementation

[0031] In this application, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0032] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0033] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] like Figure 1-2 As shown, a preferred embodiment of the battery of this application includes a current collector, a housing, and a winding core disposed inside the housing. The winding core has tabs at both ends. One surface of the current collector corresponds to each tab and is laser-welded, with a weld width of 0.2–0.4 mm. Specifically, the current collector includes a positive current collector 1 and a negative current collector 2. The negative current collector 2 is circular, with one surface connected to a negative tab, and a circular boss 5 at the center of the other surface. 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 0.1–0.3 mm, such as 0.15 mm, 0.2 mm, or 0.25 mm.

[0036] The housing has an opening, through which the core is inserted into the housing, and the boss 5 is connected to the bottom wall of the housing to make the housing negatively charged. The opening is covered by a cover, and the positive electrode current collector 1 is disposed between the cover and the positive electrode lug. The cover has a liquid injection hole, and the positive electrode current collector 1 has a liquid discharge hole that communicates with the liquid injection hole.

[0037] The other surface of the collector plate has a corresponding welding line trajectory; the welding line trajectory is wavy, and the peaks and troughs of the wavy shape are discontinuous welding trajectories.

[0038] Based on the above technical features, the battery increases the welding area between the current collector and the current collector by setting the welding line trajectory of the current collector and the electrode to a wavy shape, thereby reducing the battery's internal resistance. At the same time, by setting the peaks and troughs of the wavy shape as discontinuous welding lines, that is, by setting the corners of the welding line trajectory as discontinuous welding, the energy accumulation during welding that could damage the separator can be avoided, thus effectively ensuring the battery's performance.

[0039] In addition, to further ensure battery performance and prevent short circuits caused by separator damage, the core uses a 1.5–3.5 μm alumina-coated separator. Simultaneously, the current collector includes a welding part and an abutment part. The welding part connects to the electrode tab, and the abutment part connects to the core. The surface of the abutment part connected to the core is coated with a 50–150 μm alumina layer, such as 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, or any value between any two of these values ​​or any range thereof, to prevent short circuits caused by heat effects from welding that could damage the separator. The following specific embodiment and comparative example illustrate the effect of adding an alumina layer.

[0040] Example 1

[0041] The current collector was welded using the designed positive and negative electrode welding method, employing a 1.5–3.5 μm alumina-coated diaphragm and a current collector with a single-sided alumina coating of 50–150 μm. The diaphragm remained undamaged after welding, exhibiting low internal resistance.

[0042] Comparative Example 1

[0043] Conventional pulse spot welding was used, with 8 weld points connected at each of the four welding locations. A base membrane and an uncoated busbar (other specifications were the same) were used. After welding, the diaphragm experienced probabilistic damage (dents or shrinkage), resulting in high internal resistance.

[0044] battery cells Diaphragm appearance internal resistance value Example 1 20 / 20 No damage, no shrinkage 2.0 Comparative Example 1 Damaged / shrinked on 3 / 20 2.3 (Increase by 15%)

[0045] As can be seen from the table above, after the collector plate was coated with an alumina layer, the appearance of the diaphragm remained undamaged and the internal resistance remained unchanged; however, without the alumina layer, the appearance of three out of the twenty diaphragms was damaged, and the internal resistance increased by 15%.

[0046] In this embodiment, the bonding wire trajectory includes a first bonding wire trajectory 3 and a second bonding wire trajectory 4. Specifically, the surface of the negative electrode current collector 2 is evenly distributed with multiple first bonding wire trajectories 3 in a ring array around its center, and the first bonding wire trajectories 3 extend radially along the negative electrode current collector 2. Preferably, the negative electrode current collector 2 is provided with four first bonding wire trajectories 3, and the center lines of any two adjacent first bonding wire trajectories 3 are perpendicular.

[0047] The positive electrode current collector 1 is circular with a notch 11 for the electrode post to pass through. The notch 11 can be of different shapes, preferably semi-elliptical, thereby dividing the outer side of the positive electrode current collector 1 into an arc-shaped surface and a side plane 15. Multiple first liquid discharge holes 13 and one second liquid discharge hole 14 are evenly distributed in a ring array around the center of the surface of the positive electrode current collector 1. The arrangement of multiple liquid discharge holes can increase the permeation efficiency of the electrolyte. Preferably, there are three first liquid discharge holes 13, and the line connecting the centers of the liquid discharge holes forms a square. The second liquid discharge hole 14 is located close to the notch 11, and the radius of the second liquid discharge hole 14 is smaller than the radius of the first liquid discharge hole 13, ensuring the proper placement of the second liquid discharge hole 14. Specifically, the radius of the first liquid discharge hole 13 is 1.4–3 mm, such as 1.5 mm, 1.8 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.8 mm, etc. The radius of the second liquid outlet 14 is 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.

[0048] A first bonding wire trajectory 3 is provided between two adjacent first liquid discharge holes 13, and a second bonding wire trajectory 4 is provided between the first liquid discharge hole 13 and the second liquid discharge hole 14. That is, there are two first bonding wire trajectories 3 and two second bonding wire trajectories 4 on the positive electrode current collector 1. Both the first bonding wire trajectory 3 and the second bonding wire trajectory 4 extend radially along the positive electrode current collector 1.

[0049] like Figure 3-5As shown, the first welding wire trajectory 3 includes a first trajectory line 31 and a second trajectory line 32 connected to each other, with the first trajectory line 31 positioned close to the center of the current collector. The first trajectory line 31 is composed of multiple first trajectory units 311, and the second trajectory line 32 is composed of multiple second trajectory units 321, with the wave height of the second trajectory units 321 being greater than that of the first trajectory units 311. That is, the welding trajectory length is shorter in the inner circle and longer in the outer circle than in the center. Due to the increased curvature of the core, the outer electrode area is larger, thereby increasing the welding trajectory length and reducing the trajectory angle, increasing the welding area, and allowing for better connection between the current collector and the core, resulting in a wider connection area and lower resistance.

[0050] During setup, both the first trajectory unit 311 and the second trajectory unit 321 are determined based on the size of the liquid discharge hole, the size of the central hole 12 for needle puncture testing located at the center of the collecting plate, and the size of the collecting plate itself. Specifically:

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

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

[0053] Meanwhile, the value of R1 ranges from 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, or any value between any two of the above values ​​or any range thereof. The value of R2 ranges from 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, or any value between any two of the above values ​​or any range thereof. The value of R3 ranges from 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, or any value between any two of the above values ​​or any range thereof. The radius of the second liquid outlet is in the range of 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 any value between any two of the above values ​​or any range.

[0054] Furthermore, the line connecting the center of the central hole 12 of the positive electrode current collector 1 and the center of the second liquid discharge hole 14 is perpendicular to the side plane 15 of the positive electrode current collector 1, and the distance between the center of the central hole 12 and the perpendicular line to the side plane 15 is E, where E = 0.75R1 + R2, thereby determining the size of the notch 11. Simultaneously, the centers of the second liquid discharge hole 14, the central hole 12, and the first liquid discharge hole 13 opposite to the second liquid discharge hole 14 are on the same straight line, and this straight line is perpendicular to the side plane 15, thereby determining the position of each liquid discharge hole.

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

[0056] The first welding line 3111 includes a first main body 31111 and a first connecting part 31112. The first connecting parts 31111 of the two first welding lines 3111 intersect at the first intersection point 3112. The first connecting part 31112 is an intermittent welding trajectory, and the length of the first connecting part 31112 is L1. The value of L1 is in the range of 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 any value between any two of the above values ​​or any range. The first connecting part 31112 can be arc-shaped, in which case the value of L1 is the length of the line connecting the two ends of the arc; the first connecting part 31112 can also be a straight line.

[0057] The included angle between the two first main body parts 31111 of the first welding line 3111 is α, and the value of α is in the range of 20 to 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 part 32112. The second connecting parts 32112 of the two second welding lines 3211 intersect at the second intersection point 3212. The second connecting part 32112 is an intermittent welding trajectory, and the length of the second connecting part 32112 is L2. The value of L2 is in the range of 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 any value between any two of the above values ​​or any range. The second connecting part 32112 can be arc-shaped, in which case the value of L2 is the length of the line connecting the two ends of the arc; the second connecting part 32112 can also be a straight line.

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

[0060] In this embodiment, the second bonding wire trajectory 4 is composed of a plurality of first trajectory units 311, and the first trajectory unit 311 is the first trajectory unit 311 mentioned above, which will not be described again here.

[0061] In this embodiment, the thickness of the current collector is 0.1 to 0.6 mm, such as 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc. Under possible conditions, the current collector can be made as thick as possible, so as to better reduce its own resistance and ensure the performance of the battery.

[0062] To address the aforementioned technical problems, this application also provides a battery module, including conductive connectors and multiple batteries as described above. Two adjacent batteries are connected through the conductive connectors, and series and parallel connections between battery cells are formed by connecting the various conductive connectors.

[0063] The battery module of this application can increase the welding area between the tab and the current collector, reduce the internal resistance of the battery, avoid damage to the separator during welding, and ensure the performance of the battery module.

[0064] The above description is only a preferred embodiment of this application. 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 this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A battery, characterized in that: It includes a collector plate, a housing, and a core disposed inside the housing. The core has tabs at both ends. One surface of the collector plate is welded to the tabs in a corresponding manner, and the other surface of the collector plate has a corresponding weld line trace. The welding line trajectory is wavy, and the peaks and troughs of the wavy shape are all discontinuous welding trajectories. The current collector includes a negative current collector and a positive current collector. The positive current collector is a circle with a notch for the electrode post to pass through. The surface of the positive current collector has a plurality of first liquid discharge holes and a second liquid discharge hole evenly distributed around its center. The second liquid discharge hole is located close to the notch. A first welding wire trajectory is provided between two adjacent first liquid discharge holes. A second welding wire trajectory is provided between the first liquid discharge hole and the second liquid discharge hole. Both the first welding wire trajectory and the second welding wire trajectory extend radially along the positive current collector. The first bonding wire trajectory includes a first trajectory line and a second trajectory line connected together, and the first trajectory line is set close to the center of the current collector; the first trajectory line is composed of a plurality of first trajectory units, the second trajectory line is composed of a plurality of second trajectory units, and the wave height of the second trajectory unit is greater than the wave height of the first trajectory unit; The positive electrode current collector and the negative electrode current collector have the same radius, and the radius is R1; the center of the positive electrode current collector and the negative electrode current collector are provided with a central hole for needle puncture test, and the radius of the central hole is R2; the radius of the first liquid outlet is R3. The first trajectory unit includes two first welding lines, one end of which intersects at a first intersection point. The wave height of the first trajectory unit is H1, wherein: ; Furthermore, the value range of R1 is 8~24mm, the value range of R2 is 1.5~4mm, the value range of R3 is 1.4~3mm, the radius of the second liquid outlet is 1~2.5mm, and the thickness of the collecting plate is 0.1~0.6mm.

2. The battery as described in claim 1, characterized in that: The negative electrode current collector is circular, and multiple first bonding wire tracks are evenly distributed around its center on the surface of the negative electrode current collector, and the first bonding wire tracks themselves extend radially along the negative electrode current collector.

3. The battery as described in claim 1, characterized in that: The first welding line includes a first main body and a first connecting part. The first connecting parts of the two first welding lines intersect at the first intersection point. The first connecting part is an intermittent welding trajectory, and the length of the first connecting part is L1, with L1 ranging from 1.5 to 3.6 mm. The included angle between the two first main body parts is α, and the value of α ranges from 20 to 30°.

4. The battery as described in claim 1, characterized in that: The second trajectory unit includes two second welding lines, one end of which intersects at a second intersection point. The wave height of the second trajectory unit is H2, wherein: ; Furthermore, the value range of R1 is 8~24mm, the value range of R3 is 1.4~3mm, and the thickness of the collector plate is 0.1~0.6mm.

5. The battery as described in claim 4, characterized in that: The second welding line includes a second main body and a second connecting part. The second connecting parts of the two second welding lines intersect at the second intersection point. The second connecting part is an intermittent welding trajectory, and the length of the second connecting part is L2, with the value of L2 ranging from 1.5 to 3.6 mm. The included angle between the two second main body parts is β, and the value of β ranges from 15 to 30°.

6. The battery as described in claim 1, characterized in that: The second bonding wire trajectory is composed of several first trajectory units.

7. A battery module, characterized in that: Includes the battery as described in any one of claims 1-6.

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