Connecting piece suitable for lithium ion battery

Abstract

The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a connecting piece suitable for a lithium ion battery. According to the utility model, the plurality of heat dissipation fins are arranged on the non-welding area, so that the heat dissipation area is effectively increased, the heat dissipation speed is accelerated, the heat dissipation effect is favorably improved, and the temperature rise in the battery is further promoted to be smaller. The heat dissipation coating has good horizontal heat conductivity and vertical heat resistance effect, and is combined with the structural design of the heat dissipation fins, so that the purpose of accelerating heat conduction is achieved, heat generated at the welding part in the battery, a battery core pole piece and the like can be quickly dissipated, and a large amount of heat is effectively prevented from being accumulated in a local area in the battery. The heat dissipation efficiency is further improved, the heat distribution is uniform, the temperature is uniform, and the surface temperature rise of the connecting piece is effectively reduced under the condition that the same heat is absorbed. The connecting piece suitable for the lithium ion battery is simple in structure, convenient to install and beneficial to popularization and application in production practice.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium ion batteries, and in particular relates to a connecting piece suitable for lithium ion batteries. Background Art

[0002] The lithium-ion batteries currently on the market are mainly composed of a shell, a cover plate, a sealing nail, and a battery core. The positive and negative poles on the cover plate and the positive and negative pole ears on the battery core are electrically connected through connecting pieces by ultrasonic welding and laser welding. Since lithium-ion batteries generate a lot of heat during the charging and discharging process (only considering the direction of electronic impedance: Joule's law), their own temperature rises. Excessive temperature rise will have a great impact on battery performance and seriously affect the battery's service life, and there are also major safety hazards.

[0003] Although the outer surface of lithium-ion batteries can be forced to cool down through the external environment (such as by blowing cold air, liquid cooling, etc.), from the source, it is still necessary to improve the internal structure design of the battery to reduce the temperature of the heat source. When lithium-ion batteries are charging and discharging, the temperature distribution is mainly reflected in: the temperature of the welding part between the pole and the connecting piece > the temperature of the ultrasonic welding part between the connecting piece and the pole ear > the temperature of the battery cell pole piece. It can be seen that the design of the connecting piece has a great influence on temperature control.

[0004] The current design of the connecting piece used in lithium-ion batteries is relatively simple. The positive electrode uses an aluminum sheet and the negative electrode uses a copper sheet. The pole and the battery core are electrically connected by the connecting piece through laser welding and ultrasonic welding. However, due to the increasing market demand for fast charging of lithium-ion batteries, the temperature rise of the welding area during the charging and discharging process is directly affected. The existing methods that can be used are: increasing the thickness of the connecting piece, increasing the area of ​​the welding area, and increasing the number of pole ears on the battery core (the purpose is to reduce the internal resistance). Although it can meet the temperature rise requirements of lithium-ion battery fast charging to a certain extent, because the internal space of the battery is limited and the area of ​​the welding area is also limited, from the actual measured temperature distribution area, there is still a temperature distribution phenomenon: the temperature of the welding part of the pole and the connecting piece > the temperature of the ultrasonic welding part of the connecting piece and the pole ear > the temperature of the battery cell pole piece. Therefore, it is necessary to solve the problem of temperature rise and also consider the problem of temperature uniformity, so as to ensure the heat dissipation effect and effectively improve the charging and discharging safety of lithium-ion batteries. Utility Model Content

[0005] The utility model aims to overcome the defects of poor heat dissipation effect of the connecting piece in the prior art, which causes excessive temperature rise inside the battery, uneven heat distribution and easy accumulation, and provides a connecting piece suitable for lithium ion batteries to overcome the above defects.

[0006] In order to achieve the purpose of the above invention, the utility model is implemented through the following technical solutions:

[0007] A connecting piece suitable for lithium-ion batteries is arranged in cooperation with a battery cover plate and a pole ear on a battery coil core. The connecting piece includes a plurality of welding areas and a non-welding area. A plurality of heat dissipation fins are arranged on the non-welding area. The surface of the heat dissipation fins is coated with a heat dissipation coating.

[0008] The utility model provides a connecting piece suitable for lithium-ion batteries, which is arranged in cooperation with the battery cover plate and the pole ears on the battery coil core. The connecting piece includes a plurality of welding areas and non-welding areas, and a plurality of heat dissipation fins are arranged on the non-welding areas, and the surface of the heat dissipation fins is coated with a heat dissipation coating. The utility model effectively increases the heat dissipation area and accelerates the heat dissipation speed by arranging a plurality of heat dissipation fins on the non-welding area, which helps to improve the heat dissipation effect and further promotes a smaller temperature rise inside the battery. In addition, the utility model utilizes the good horizontal thermal conductivity and vertical heat resistance of the heat dissipation coating, combined with the structural design of the heat dissipation fins, to achieve the purpose of accelerating heat conduction, so that the heat generated in the welding parts and the battery cell pole pieces inside the battery can be quickly dissipated, effectively avoiding a large amount of heat accumulation in local areas of the battery. The heat dissipation efficiency is further improved, thereby achieving uniform heat distribution and uniform temperature, and effectively reducing the surface temperature rise of the connecting piece when absorbing the same amount of heat.

[0009] Preferably, the welding area includes at least one laser welding area and at least two ultrasonic welding areas, and the laser welding area and the ultrasonic welding area are arranged parallel to each other.

[0010] Preferably, ultrasonic welding areas are symmetrically arranged on both sides of the connecting sheet and on the surface of the connecting sheet, and a laser welding area is arranged above the connecting sheet and on the surface of the connecting sheet.

[0011] Preferably, the width of the laser welding area is longer than the width of the ultrasonic welding area, and the length of the laser welding area is shorter than the length of the ultrasonic welding area.

[0012] Preferably, the connecting piece is provided with a protrusion extending outwardly along the length direction of the laser welding area, and one side of the protrusion is provided with a chamfer.

[0013] By setting the chamfer, it plays a guiding and positioning role when the connecting piece is assembled, which is convenient for subsequent processing and assembly. It effectively prevents the connecting piece from being placed in the wrong direction when it is electrically connected to the battery coil core and the battery cover.

[0014] Preferably, the connecting piece is provided with an inner recess extending inwardly along the length direction of the laser welding area.

[0015] Providing the inner recess helps to increase the local strength and rigidity of the connecting piece, enhance the mechanical properties of the connecting piece, and save materials, which helps to reduce production costs.

[0016] As a further preference, the inner recessed portion has a U-shaped structure.

[0017] Preferably, gaps are provided between adjacent heat dissipation fins and the fins are arranged parallel to each other.

[0018] The above arrangement helps to improve the heat dissipation efficiency, effectively prevents heat accumulation on the surface of the heat dissipation fins, reduces thermal resistance, and further improves the heat dissipation effect. In addition, the gap and parallel arrangement between adjacent heat dissipation fins help to reduce thermal stress caused by temperature changes, thereby improving the structural stability of the heat dissipation fins. At the same time, it is also convenient for later inspection and maintenance, effectively improving the service life of the connecting piece.

[0019] Preferably, the cross section of the heat dissipation fin is rectangular or trapezoidal.

[0020] Preferably, the plurality of heat dissipation fins and the connecting sheet are integrally formed.

[0021] Preferably, the heat dissipation coating is a graphene or carbon nanotube material coating.

[0022] Both graphene and carbon nanotubes have efficient thermal conductivity and can quickly transfer heat from the heat source to a larger heat dissipation area, thereby accelerating heat conduction. Using graphene or carbon nanotube materials as heat dissipation coatings allows the heat generated in the welding parts inside the battery and the battery core pole pieces to be quickly dissipated, effectively avoiding the accumulation of large amounts of heat in local areas of the battery, further improving the heat dissipation efficiency. The structural design of coating the heat dissipation coating on the surface of the heat dissipation fins helps to achieve uniform heat distribution and uniform temperature, and effectively reduces the temperature rise on the surface of the connecting piece when absorbing the same amount of heat. In addition, graphene and carbon nanotube materials also have the excellent characteristics of light weight, high strength, good chemical stability, and strong adhesion.

[0023] Therefore, the utility model has the following beneficial effects:

[0024] (1) The utility model provides a plurality of heat dissipation fins on the non-welding area, which effectively increases the heat dissipation area, speeds up the heat dissipation speed, helps to improve the heat dissipation effect, and further promotes a smaller temperature rise inside the battery;

[0025] (2) The utility model utilizes the good horizontal thermal conductivity and vertical heat resistance of the heat dissipation coating, combined with the structural design of the heat dissipation fins, to achieve the purpose of accelerating heat conduction, so that the heat generated by the welding parts inside the battery and the battery cell poles can be quickly dissipated, effectively avoiding the accumulation of large amounts of heat in local areas of the battery. The heat dissipation efficiency is further improved, thereby achieving uniform heat distribution and uniform temperature, and effectively reducing the temperature rise on the surface of the connecting piece when absorbing the same amount of heat;

[0026] (3) The connecting piece of the utility model suitable for lithium-ion batteries has a simple structure and is easy to install, which is conducive to popularization and application in production practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of a connecting piece suitable for lithium-ion batteries.

[0028] Figure 2 It is a schematic diagram of the structure of the heat dissipation fins on the connecting plate.

[0029] Figure 3 Schematic diagram of the assembly of the connecting piece.

[0030] In the figure: battery cover 1; battery roll core 2; pole ear 3; connecting piece 4; welding area 5; non-welding area 6; heat dissipation fin 7; laser welding area 8; ultrasonic welding area 9; raised part 10; chamfer 11; inner recess 12. DETAILED DESCRIPTION

[0031] The utility model is further described below in conjunction with the drawings and specific embodiments of the specification. A person of ordinary skill in the art will be able to implement the utility model based on these descriptions. In addition, the embodiments of the utility model involved in the following description are usually only embodiments of a part of the utility model, rather than all of the embodiments. Therefore, based on the embodiments in the utility model, all other embodiments obtained by a person of ordinary skill in the art without making creative work should fall within the scope of protection of the utility model.

[0032] like Figure 1-3As shown, the utility model provides a connecting piece 4 suitable for lithium-ion batteries, which is arranged in cooperation with the battery cover plate 1 and the pole ear 3 on the battery coil core 2. The connecting piece 4 includes a plurality of welding areas 5 and a non-welding area 6, and a plurality of heat dissipation fins 7 are arranged on the non-welding area 6, and the surface of the heat dissipation fins 7 is coated with a heat dissipation coating. The utility model effectively increases the heat dissipation area and accelerates the heat dissipation speed by arranging a plurality of heat dissipation fins 7 on the non-welding area 6, which helps to improve the heat dissipation effect and further promotes a smaller temperature rise inside the battery. In addition, the utility model utilizes the good horizontal thermal conductivity and vertical heat resistance of the heat dissipation coating, combined with the structural design of the heat dissipation fins 7, to achieve the purpose of accelerating heat conduction, so that the heat generated at the welding parts and the battery cell pole pieces inside the battery can be quickly dissipated, effectively avoiding a large amount of heat accumulation in a local area of ​​the battery. The heat dissipation efficiency is further improved, thereby achieving uniform heat distribution and uniform temperature, and effectively reducing the surface temperature rise of the connecting piece 4 when absorbing the same amount of heat.

[0033] As an embodiment, the welding area 5 includes at least one laser welding area 8 and at least two ultrasonic welding areas 9, and the laser welding area 8 and the ultrasonic welding area 9 are arranged parallel to each other.

[0034] As an implementation manner, ultrasonic welding areas 9 are symmetrically arranged on both sides of the connecting sheet 4 and on the surface of the connecting sheet 4 , and a laser welding area 8 is arranged above the connecting sheet 4 and on the surface of the connecting sheet 4 .

[0035] As an implementation manner, the width of the laser welding area 8 is longer than the width of the ultrasonic welding area 9 , and the length of the laser welding area 8 is shorter than the length of the ultrasonic welding area 9 .

[0036] As an implementation manner, the connection sheet 4 is provided with a protrusion 10 extending outwardly along the length direction of the laser welding area 8 , and a chamfer 11 is provided on one side of the protrusion 10 .

[0037] The chamfer 11 is provided to guide and position the connecting piece 4 during assembly, facilitating subsequent processing and assembly, thereby effectively preventing the connecting piece 4 from being placed in the wrong direction when electrically connecting the battery coil core 2 and the battery cover plate 1 .

[0038] As an implementation manner, the connecting sheet 4 is provided with an inner recess 12 extending inwardly along the length direction of the laser welding area 8 .

[0039] The inner recess 12 is provided to increase the local strength and rigidity of the connecting piece 4 and enhance the mechanical properties of the connecting piece 4 . At the same time, it can save materials and help reduce production costs.

[0040] As another embodiment, the inner recess 12 is a U-shaped structure.

[0041] As an implementation mode, gaps are provided between adjacent heat dissipation fins 7 and the fins 7 are arranged parallel to each other.

[0042] The above arrangement helps to improve the heat dissipation efficiency, effectively prevents heat from accumulating on the surface of the heat dissipation fins 7, reduces thermal resistance, and further improves the heat dissipation effect. In addition, the gaps and parallel arrangement between adjacent heat dissipation fins 7 help to reduce thermal stress caused by temperature changes, thereby improving the structural stability of the heat dissipation fins 7. At the same time, it is also convenient for later inspection and maintenance, effectively improving the service life of the connecting sheet 4.

[0043] As an implementation manner, the cross section of the heat dissipation fin 7 is rectangular or trapezoidal.

[0044] As an implementation mode, a plurality of heat dissipation fins 7 and the connecting sheet 4 are integrally formed.

[0045] As an implementation manner, the heat dissipation coating is a graphene or carbon nanotube material coating.

[0046] Both graphene and carbon nanotubes have efficient thermal conductivity and can quickly conduct heat from the heat source to a larger heat dissipation area to accelerate heat conduction. Using graphene or carbon nanotube materials as heat dissipation coatings allows the heat generated in the welding parts inside the battery and the pole pieces of the battery core 2 to be quickly dissipated, effectively avoiding the accumulation of large amounts of heat in local areas of the battery, further improving the heat dissipation efficiency. The structural design of coating the heat dissipation coating on the surface of the heat dissipation fins 7 helps to achieve uniform heat distribution and uniform temperature, and effectively reduces the temperature rise on the surface of the connecting piece 4 when absorbing the same amount of heat. In addition, graphene and carbon nanotube materials also have the excellent characteristics of light weight, high strength, good chemical stability, and strong adhesion.

[0047] As another implementation, a plurality of heat dissipation fins 7 may be provided on both the front and back sides of the connection sheet 4 , and a heat dissipation coating may be coated on the surface of the heat dissipation fins 7 .

Claims

1. A connecting sheet suitable for a lithium-ion battery, which is arranged in cooperation with a battery cover plate (1) and a tab (3) on a battery coil core (2), characterized in that: The connecting sheet (4) comprises a plurality of welding areas (5) and a non-welding area (6); a plurality of heat dissipation fins (7) are arranged on the non-welding area (6); and the surface of the heat dissipation fins (7) is coated with a heat dissipation coating.

2. A connecting sheet suitable for lithium-ion batteries according to claim 1, characterized in that: The welding area (5) comprises at least one laser welding area (8) and at least two ultrasonic welding areas (9), and the laser welding area (8) and the ultrasonic welding area (9) are arranged parallel to each other.

3. A connecting sheet suitable for lithium-ion batteries according to claim 1 or 2, characterized in that: Ultrasonic welding areas (9) are symmetrically arranged on both sides of the connecting sheet (4) and located on the surface of the connecting sheet (4), and a laser welding area (8) is arranged above the connecting sheet (4) and located on the surface of the connecting sheet (4).

4. A connecting sheet suitable for lithium-ion batteries according to claim 2, characterized in that: The width of the laser welding area (8) is longer than the width of the ultrasonic welding area (9), and the length of the laser welding area (8) is shorter than the length of the ultrasonic welding area (9).

5. A connecting sheet suitable for lithium-ion batteries according to claim 2 or 4, characterized in that: The connecting piece (4) is provided with a protrusion (10) extending outwardly along the length direction of the laser welding area (8), and a chamfer (11) is provided on one side of the protrusion (10).

6. A connecting sheet suitable for lithium-ion batteries according to claim 2 or 4, characterized in that: The connecting piece (4) is provided with an inner recess (12) extending inwardly along the length direction of the laser welding area (8).

7. A connecting sheet suitable for lithium-ion batteries according to claim 1, characterized in that: Adjacent heat dissipation fins (7) are provided with gaps between them and are arranged parallel to each other.

8. A connecting sheet suitable for lithium-ion batteries according to claim 1 or 7, characterized in that: The cross section of the heat dissipation fin (7) is rectangular or trapezoidal.

9. A connecting sheet suitable for lithium-ion batteries according to claim 8, characterized in that: A plurality of heat dissipation fins (7) and the connecting sheet (4) are integrally formed.

10. The connecting sheet suitable for lithium-ion batteries according to claim 1, characterized in that: The heat dissipation coating is a graphene or carbon nanotube material coating.

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