Current collector and battery
By introducing buffer and weak point designs into the current collector, the problem of the inability to release cell expansion pressure was solved, thus improving battery safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- EVE POWER CO LTD
- Filing Date
- 2022-07-28
- Publication Date
- 2026-07-31
AI Technical Summary
Existing current collector structures cannot effectively release the cell expansion pressure in cylindrical lithium-ion batteries, resulting in insufficient safety.
Design a current collector, comprising a collector body, a buffer, and a weak member. The buffer is pressed against the battery casing, and the weak member connects the buffer and the collector body. When the cell expands, the weak member breaks, and the buffer deforms to absorb the pressure and provide expansion space.
This improves battery safety, ensures that the cell expansion pressure can be fully released, avoids battery explosion, and enhances the battery's safety factor.
Smart Images
Figure CN115207360B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of batteries, and more particularly to a current collector and a battery including the current collector. Background Technology
[0002] As lithium-ion batteries are increasingly used in electric bicycles, electric vehicles, and large-scale energy storage power stations, the industry is placing increasingly higher demands on their specifications, technical performance, and reliability. Among these, cylindrical lithium-ion batteries are attracting significant attention due to their high energy density, low cost, and good safety performance.
[0003] When assembling cylindrical lithium-ion batteries, a current collector is typically used to connect the tabs to the battery cap. One end of the current collector is welded to the battery tab using laser welding, while the other end is connected to the battery cap by welding or riveting, thus sealing the cylindrical lithium-ion battery and forming a current loop.
[0004] As a current collector, the current collector has been found to be strongly correlated with cell safety in cylindrical lithium-ion battery research. However, the safety function of existing current collector structures is relatively weak. When the cell expands, the current collector cannot effectively release the expansion pressure, thus failing to meet the battery's safety requirements. Summary of the Invention
[0005] One objective of this invention is to provide a current collector that has a simple structure and can provide expansion space for the battery cell.
[0006] Another objective of this invention is to provide a battery with a high safety factor.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] In a first aspect, a current collector is provided, comprising a collector body and a buffer member, wherein at least two buffer members are provided, each buffer member having a bent abutment portion protruding from the side of the collector body away from the battery cell, the abutment portion abutting against the battery casing, one end of two adjacent buffer members being connected by a weak member, and the end of the buffer member away from the weak member being connected to the collector body.
[0009] As a preferred embodiment of the current collector, the disk body is provided with at least two current collector plates, which are used to be welded to the tabs of the battery cell. The current collector plates are spaced apart from the buffer. Each current collector plate includes a current collector body and a connecting part. The connecting part protrudes from the current collector body on the side close to the disk body and is connected to the disk body. The current collector body is spaced apart from the disk body.
[0010] As a preferred embodiment of the current collection plate, the plate body is annular, the current collection plate is located within the annular area of the plate body, and the shape of the current collection plate matches the area enclosed by the plate body, the buffer, and the weak member.
[0011] As a preferred embodiment of the current collection disk, the buffer components are evenly distributed in a ring around the circumference of the disk body, and a current collection plate is provided between two adjacent buffer components.
[0012] As a preferred embodiment of the collector plate, the spacing between the collector plate and the buffer element is 0.6mm-2mm; and / or,
[0013] The distance between the current collector plate and the disk body is 0.3mm-0.8mm; and / or,
[0014] The current collector is in the shape of a fan ring, with an inner diameter of 12mm-18mm and an outer diameter of 40mm-44.5mm.
[0015] As a preferred embodiment of the current collector, two adjacent buffer components are connected by a weak component, and all the buffer components are enclosed by the weak component to form a first through hole, which is directly opposite to the center of the battery cell.
[0016] As a preferred embodiment of the collector plate, the buffer is provided with a second through hole.
[0017] As a preferred embodiment of the collector plate, the outer periphery of the plate body is provided with a flange.
[0018] As a preferred embodiment of the collector plate, the bent area of the flange is provided with a plurality of third through holes, which are arranged at intervals along the circumference of the plate body.
[0019] As a preferred embodiment of the manifold, the flange is on the same side as the abutting portion.
[0020] As a preferred embodiment of the manifold, the cross-sectional shape of the contact portion is arc-shaped, flat-topped, or wavy.
[0021] As a preferred embodiment of the collector plate, the width of the plate body is 1mm-3mm, and the width of the weak member is 0.3mm-0.8mm.
[0022] Secondly, a battery is provided, including a housing and the aforementioned current collector, wherein the housing includes a housing body and a cover plate, a sealing element is provided between the housing body and the cover plate, the current collector body is connected to the housing body, and a buffer element abuts against the cover plate.
[0023] The beneficial effects of this invention are as follows: by setting a weak component to connect the buffer component, when the battery cell undergoes thermal runaway expansion, the pressure generated by the expansion of the battery cell or the pressure inside the buffer cavity can squeeze the current collector, causing the weak component on the current collector to break. After the weak component breaks, the bent buffer component can deform to absorb the pressure generated by the expansion of the battery cell, so that the expansion pressure of the battery cell can be fully released. Attached Figure Description
[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.
[0025] Figure 1 This is a schematic diagram of the collector disk as described in an embodiment of the present invention.
[0026] Figure 2 for Figure 1 Enlarged diagram of point A.
[0027] Figure 3 This is a schematic diagram of the collector disk from another perspective according to an embodiment of the present invention.
[0028] Figure 4 for Figure 3 Enlarged diagram of point B.
[0029] Figure 5 for Figure 3 Enlarged diagram of point C.
[0030] In the picture:
[0031] 1. Disc body; 2. Collector plate; 3. Buffer component; 301. First plate; 302. Second plate; 303. Abutment part; 304. Second through hole; 4. Weak component; 5. First through hole; 6. Flanged edge; 601. Third through hole. Detailed Implementation
[0032] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0033] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" 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 invention based on the specific circumstances.
[0034] like Figures 1 to 3 As shown, the present invention provides a current collector, including a disk body 1 and a buffer 3. At least two buffers 3 are provided. Each buffer 3 is bent into an abutment portion 303. The abutment portion 303 protrudes from the side of the disk body 1 away from the battery cell and abuts against the battery casing. One end of two adjacent buffers 3 is connected by a weak member 4. The end of the buffer 3 away from the weak member 4 is connected to the disk body 1. The weak member 4 can be broken by the expansion and compression of the battery cell. In this embodiment, the current collector is disposed inside the battery casing and located on one side of the battery cell. One side of the current collector is pressed against the battery cell, and the other side is pressed against the inner wall of the end of the battery casing, so that a buffer cavity is formed between the battery cell and the battery casing. The buffer 3 is connected by a weak member 4. When the battery cell undergoes thermal runaway expansion, the pressure generated by the battery cell or the pressure inside the buffer cavity can squeeze the current collector, causing the weak member 4 on the current collector to break. After the weak member 4 breaks, the bent buffer 3 can deform to absorb the pressure generated by the expansion of the battery cell, so that the expansion pressure of the battery cell can be fully released.
[0035] In this embodiment, the width of the disk body 1 is 1mm-3mm, referring to... Figure 2 The width L1 of the weak component 4 is 0.3mm-0.8mm. By limiting the width of the disk body 1, the strength of the disk body 1 can be guaranteed, ensuring the connection stability between the current collector and the battery casing. By limiting the width of the weak component 4, the strength of the weak component 4 can be guaranteed. When the battery cell expands normally, the weak component 4 will not break. When the battery cell undergoes thermal runaway expansion, the weak component 4 will be broken by the pressure generated by the expansion of the battery cell or the pressure inside the buffer cavity.
[0036] Specifically, at least two current collectors 2 are provided on the disk body 1. The current collectors 2 are spaced apart from the buffer 3. Each current collector 2 includes a current collector body and a connecting part. The connecting part protrudes from the current collector body on the side near the disk body 1 and is connected to the disk body 1. The current collector body is spaced apart from the disk body 1. In this embodiment, the current collectors 2 are welded to the tabs of the battery cell. The current collectors 2 transmit the current from the battery cell to the battery casing. By setting the current collectors 2 spaced apart from the disk body 1 and spaced apart from the buffer 3, when the battery cell generates gas and expands, the spaced areas between the current collectors 2 and the disk body 1 and between the current collectors 2 and the buffer 3 can form unobstructed exhaust channels, allowing the gas generated by the battery cell to be discharged in a timely manner.
[0037] Specifically, the disk body 1 is annular, and the current collector 2 is located within the annular area of the disk body 1. The shape of the current collector body matches the area enclosed by the disk body 1, the buffer 3, and the weak member 4. In this embodiment, the current collector body is fan-shaped. By setting the current collector body to be fan-shaped, the shape of the current collector 2 can be adapted to the disk body 1, increasing the welding area between the current collector 2 and the battery cell, and ensuring that the battery can supply power stably.
[0038] In this embodiment, the spacing between the current collector 2 and the buffer 3 is 0.6mm-2mm. The current collector 2 is a fan ring with an inner diameter of 12mm-18mm. When the battery cell experiences thermal runaway, it ensures that the battery cell has sufficient space for core removal. The outer diameter of the current collector 2 is 40mm-44.5mm. A gap of 0.3mm-0.8mm is maintained between the current collector 2 and the disk body 1. When the battery cell experiences thermal runaway, the current collector 2 can move together with the battery cell's tabs to prevent the gas generated by the battery cell from being unable to escape smoothly, which could lead to the battery cell exploding.
[0039] Specifically, the buffer members 3 are evenly distributed in a ring around the circumference of the disk body 1, and a current collector 2 is disposed between two adjacent buffer members 3. By providing buffer members 3 in a ring around the circumference of the disk body 1, the contact parts 303 can be evenly distributed in the circumference of the disk body 1, so that the current collector disk and the battery casing can make uniform contact. In this embodiment, three buffer members 3 and three current collector 2 are provided. The three buffer members 3 are evenly distributed in the circumference of the disk body 1, and the three current collector 2 are also evenly distributed in the circumference of the disk body 1.
[0040] Specifically, the buffer 3 includes a first piece 301 and a second piece 302 connected at an angle. The first piece 301 is connected to the disk body 1, and the second piece 302 is connected to the weak member 4. The first piece 301 and the second piece 302 are connected to form an abutment portion 303, which abuts against the shell. The abutment portions 303 of all buffer 3 have the same height, meaning that the abutment force between the abutment portions 303 of all buffer 3 and the shell is the same. By setting the first piece 301 and the second piece 302, the bent buffer 3 can increase the venting channels of the battery cell and improve the thermal runaway safety of the battery cell. By setting all the abutment portions 303 to have the same height, the abutment force between all the buffer 3 and the shell can be made consistent, so that the weak member 4 can be subjected to uniform force and avoid the weak member 4 being squeezed and broken by other external forces. In this embodiment, the width of the buffer 3 is 4mm-8mm, that is, the width of the first piece 301 and the second piece 302 is 4mm-8mm, which ensures that the buffer 3 can provide sufficient rebound force after being compressed; the height of the abutting part 303 of all buffers 3 is 1.5mm-3mm, where the height refers to the distance between the abutting part 303 and the side of the disk body 1 away from the battery cell.
[0041] The buffer member 3 is formed by bending, and the bent portion of the buffer member 3 is the abutment portion 303. In this embodiment, the buffer member 3 is bent once, and the cross-sectional shape of the abutment portion 303 is arc-shaped. In other embodiments, the buffer member 3 can be bent multiple times. For example, the buffer member 3 can be bent twice, and the portion between the two bending positions forms the abutment portion 303. In this case, the abutment portion 303 is flat-topped. Or, the buffer member 3 can be bent three or more times, and the portion between the two outermost bending positions forms the abutment portion 303. In this case, the abutment portion 303 is wavy. By setting abutment portions 303 of various shapes, the strength of the buffer member 3 can be changed, thereby adjusting the preload between the current collector and the battery cell.
[0042] Specifically, multiple weak points 4 are provided, and adjacent buffers 3 are connected by a weak point 4. All buffers 3 are enclosed by the weak points 4 to form a first through hole 5, which is directly opposite the center of the battery cell. By providing the first through hole 5, the venting channel of the battery cell can be increased, allowing for better venting during winding. The first through hole 5 also improves the flexibility of the buffers 3; when the weak point 4 breaks, the bent buffer 3 can straighten, thereby allowing the buffer 3 to deform and absorb the expansion of the battery cell. In this embodiment, the width of the first through hole 5 is 8mm-12mm.
[0043] Specifically, the buffer 3 is provided with a second through hole 304. In this embodiment, the second through hole 304 is provided on the first piece 301 and extends to the second piece 302. The provision of the second through hole 304 can further increase the venting channel of the battery cell, so that the battery cell can better vent during winding.
[0044] Reference Figures 3 to 5 Specifically, the outer periphery of the disk body 1 is provided with a flange 6. In this embodiment, the flange 6 is welded to the battery casing, and the battery casing is provided with a narrowing structure. The flange 6 is located below the narrowing. By providing the flange 6, the strength of the disk body 1 can be improved, ensuring the reliability of the electrical connection between the current collector and the battery casing, and preventing the current collector from deforming during the narrowing process. This avoids the current collector deforming and squeezing the battery cell or inserting into the battery cell at this stage, which could lead to a battery cell open circuit failure. In this embodiment, three flanges 6 are provided, and the three flanges 6 are evenly spaced along the periphery of the disk body 1. The arc length of each flange 6 is 13mm-25mm, and the width H is 1.5mm-3mm.
[0045] In this embodiment, the flange 6 is on the same side as the abutment portion 303, and the flange 6 is pressed against the side of the constriction. It can be understood that the flange 6 has a certain elasticity after bending, and the abutment portion 303 of the current collector is pressed against the battery casing. Both the flange 6 and the abutment portion 303 can provide pre-tightening force. Setting the flange 6 and the abutment portion 303 on the same side can also reduce the space occupied by the current collector, thereby reducing the size of the battery.
[0046] In this embodiment, the bending area of the flange 6 is provided with multiple third through holes 601, which are arranged at intervals along the circumference of the disk body 1. By providing the third through holes 601, the strength of the bending area of the flange 6 can be reduced, thereby improving the deformation capacity of the bending area of the flange 6, reducing the thickness of the flange 6 after bending, reducing the core compression of the battery cell, and improving the safety of the battery cell. In this embodiment, the thickness D of the bending area of the flange 6 is 0.5mm-1.2mm, the distance L2 between two adjacent third through holes 601 is 2.5mm-5mm, the arc length of the flange 6 is H, and the length L3 of the third through hole 601 is 0.3H.
[0047] In this embodiment, the flow collector is integrally formed, that is, the structure of the disk body 1, the flow collector plate 2, the buffer 3, the flange 6, the weak part 4, etc. are integrally formed, and the buffer 3 can be formed by stamping.
[0048] This embodiment also provides a battery, including a casing and a current collector as described in any of the above embodiments. The casing includes a casing body and a cover plate, with a sealing element provided between the casing body and the cover plate. The current collector plate's disk body 1 is welded to the casing body, and the buffer 3 is pressed against the cover plate. In one embodiment, the casing body and the cover plate are integrally formed. In this case, the cover plate can be bent from a blank of the casing body. In this embodiment, the casing body and the cover plate are two separate parts, and the gap between them is sealed by the sealing element. In this embodiment, the casing body is connected to the negative electrode of the battery cell through the disk body 1. At this time, the casing body is negatively charged. A sealing element is provided between the cover plate and the casing body. The sealing element is usually made of materials such as rubber and has an insulating function. By setting the buffer 3 to press against the cover plate, the cover plate can be negatively charged to form cathodic protection, improve the corrosion resistance of the cover plate, and thus ensure the safety of the battery cell cover plate. The formed and bent buffer 3 can also give the buffer 3 sufficient rebound force, so that it can fully rebound after being pressed down, ensuring the effectiveness of the cathodic protection of the cover plate.
[0049] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings, and are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are used merely for descriptive distinction and have no special meaning.
[0050] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.
[0051] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
[0052] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.
Claims
1. A current collector plate, characterized by, The device includes a disk body and a buffer component. At least two buffer components are provided. Each buffer component has a bent abutment portion that protrudes from the side of the disk body away from the battery cell and abuts against the battery casing. One end of two adjacent buffer components is connected by a weak member. The end of the buffer component away from the weak member is connected to the disk body. When the battery cell undergoes thermal runaway expansion, the weak member on the current collector disk breaks. After the weak member breaks, the expansion pressure of the battery cell can be fully released. The buffer includes a first piece and a second piece connected at an angle. The first piece is connected to the disk body, and the second piece is connected to the weak member. The first piece and the second piece are connected to form the abutment portion. The width of the disk body is 1mm-3mm, and the width of the weak component is 0.3mm-0.8mm.
2. The collector disk according to claim 1, characterized in that, The disk body is provided with at least two current collectors, which are used to be welded to the tabs of the battery cell. The current collectors are spaced apart from the buffer. Each current collector includes a current collector body and a connecting part. The connecting part protrudes from the current collector body on the side close to the disk body and is connected to the disk body. The current collector body is spaced apart from the disk body.
3. The collector disk according to claim 2, characterized in that, The disk body is annular, the current collector is located within the annular area of the disk body, and the shape of the current collector matches the area enclosed by the disk body, the buffer, and the weak member.
4. The collector disk according to claim 2, characterized in that, The buffer components are evenly distributed in a ring around the circumference of the disk body, and a current collector is provided between two adjacent buffer components.
5. The collector disk according to claim 2, characterized in that, The distance between the current collector and the buffer is 0.6mm-2mm; and / or, The distance between the current collector plate and the disk body is 0.3mm-0.8mm; and / or, The current collector is in the shape of a fan ring, with an inner diameter of 12mm-18mm and an outer diameter of 40mm-44.5mm.
6. The collector disk according to claim 1, characterized in that, Two adjacent buffer components are connected by a weak component, and all the buffer components are enclosed by the weak component to form a first through hole, which is directly opposite to the center of the battery cell.
7. The collector disk according to claim 1, characterized in that, The buffer component is provided with a second through hole.
8. The collector disk according to claim 1, characterized in that, The outer periphery of the disk body is provided with a flange.
9. The collector disk according to claim 8, characterized in that, The bent area of the flange is provided with a plurality of third through holes, which are arranged at intervals along the circumference of the disk body.
10. The collector disk according to claim 8, characterized in that, The flange is on the same side as the abutting part.
11. The collector disk according to claim 1, characterized in that, The cross-sectional shape of the contact portion is arc-shaped, flat-topped, or wavy.
12. A battery, comprising a casing, the casing including a casing body and a cover plate, wherein a sealing element is disposed between the casing body and the cover plate, characterized in that, It also includes a collector plate as described in any one of claims 1-11, wherein the plate body of the collector plate is connected to the shell body, and the buffer member abuts against the cover plate.