A battery connection piece and a preparation method thereof

Abstract

The present invention discloses a battery connection piece and a preparation method thereof. The battery connection piece includes a conductive layer and a heat dissipation layer. The conductive layer is disposed at the bottom of the heat dissipation layer. An insulating layer is provided between the conductive layer and the heat dissipation layer. The conductive layer and the heat dissipation layer are bonded together through the insulating layer to form a battery connection piece with a composite structure. A protective layer is integrally formed at the bottom of the conductive layer. A main channel is formed in the heat dissipation layer along the long side direction, and a plurality of branch channels are formed on both sides of the main channel in a communicating manner. The battery connection piece provided by the present invention combines the conductive layer, the heat dissipation layer and the insulating layer to form a battery connection piece with a composite mechanism. The thermoelectric separation of the battery connection piece is realized through the insulation and heat conduction of the insulating layer. The temperature of the conductive layer is ensured to be stable by isolating heat dissipation, thereby reducing the fluctuation of the resistance of the conductive layer. At the same time, the insulating layer blocks the path of galvanic corrosion, effectively extending the service life of the battery connection piece.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery connection sheets, and particularly relates to a battery connection sheet and a preparation method thereof. Background Art

[0002] With the popularization of new energy vehicles, the service life and safety of batteries have become the most important aspects of new energy development. Battery connection sheets are crucial components in battery packs. A battery connection sheet refers to a component or part used to connect batteries, usually for establishing electrical connections between batteries or between batteries and other electronic devices. They play an important role in battery technology, especially in battery assembly and battery management systems. Battery connection sheets are usually made of conductive materials such as copper because they can effectively transfer current. These connection sheets can adopt different shapes and designs to adapt to specific types of batteries and connection requirements. They may have different connection methods, such as welding, threaded connection, crimping, etc., depending on the application and design. During battery assembly, battery connection sheets are used to connect multiple battery cells together to create a battery pack, which helps increase the voltage and capacity of the battery pack.

[0003] In short, battery connection sheets are key components in battery technology, used to establish electrical connections between batteries and between batteries and other electronic devices to ensure effective current transmission and achieve the required electrical energy transfer.

[0004] Existing battery connection sheets have the following problems:

[0005] 1. Resistance and heat generation: Pure metal sheets (such as copper and aluminum) are prone to oxidation, resulting in an increase in contact resistance, and serious local heat generation under high-current conditions;

[0006] 2. Insufficient corrosion resistance: Traditional plating processes (such as nickel plating) are prone to peeling in high-temperature and high-humidity environments, leading to electrochemical corrosion;

[0007] 3. Poor mechanical adaptability: The rigid structure is prone to stress concentration during battery pack vibration or expansion, and there is a risk of fracture.

[0008] Due to the problems of excessive resistance leading to heat generation, easy corrosion, and insufficient mechanical strength in the above battery connection sheets, the service life and safety of battery use are affected, which has become an urgent problem to be solved in the development of new energy vehicles.

[0009] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of implication that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0010] The object of the present invention is to provide a battery connection piece and a preparation method thereof, which can solve the problems that the excessive resistance of the battery connection piece causes heat generation, easy corrosion and insufficient mechanical strength, affecting the service life and safety of the battery during use.

[0011] In order to achieve the above object, the technical solution provided by a specific embodiment of the present invention is as follows:

[0012] A battery connection piece includes a conductive layer and a heat dissipation layer. The conductive layer is arranged at the bottom of the heat dissipation layer, and an insulating layer is arranged between the conductive layer and the heat dissipation layer. The conductive layer and the heat dissipation layer are bonded together through the insulating layer to form a battery connection piece with a composite structure. By bonding the conductive layer, the heat dissipation layer and the insulating layer together to form a battery connection piece with a composite structure, the structural composition of the traditional integrated electrical connection piece is changed. A protective layer is integrally formed at the bottom of the conductive layer. The protective layer is used to protect the surface of the conductive layer, preventing the conductive layer from being corroded during use. At the same time, when the surface of the conductive layer is scratched, self-repair of the anti-corrosion layer can be carried out to ensure that electrochemical corrosion does not occur when the connection piece is used in a high-temperature and high-humidity environment. A main channel is opened in the heat dissipation layer along the long side direction. A plurality of branch channels are opened on both sides of the main channel in a communicating manner. The main channel and the plurality of branch channels form a vein-like channel, and a heat-conducting phase-change material is filled in the main channel. When local heating of the battery cell is serious under high-current working conditions, the heat on the conductive layer will be quickly transferred to the heat dissipation layer through the insulating layer. The heat-conducting phase-change material in the main channel will absorb heat quickly and efficiently. After the heat-conducting phase-change material absorbs heat and melts, it will flow in the plurality of branch channels, so that the heat-conducting phase-change material absorbs heat and circulates in the form of a vein-like micro-channel, realizing active heat dissipation, thereby effectively avoiding the overheating of the local temperature of the insulating layer under high-current working conditions, ensuring the normal temperature of the surface of the insulating layer under high-current working conditions, and thus ensuring the safety of the battery connection piece during use. A plurality of second buffer grooves are opened on both sides of the long edge of the heat dissipation layer, so that the long edge of the battery connection piece with a composite structure is provided with second buffer grooves, effectively improving the anti-vibration fatigue performance of the battery connection piece and absorbing the transverse stress generated by the expansion of the battery during charging and discharging.

[0013] In one or more embodiments of the present invention, a plurality of first buffer grooves are opened on both sides of the long edge of the conductive layer, effectively improving the anti-vibration fatigue performance of the conductive layer and absorbing the transverse stress generated by the expansion of the battery during charging and discharging. At least two of the plurality of first buffer grooves are provided. The depths of the plurality of first buffer grooves are set in a manner that gradually increases from the center of the conductive layer to the outside. The depth of the first buffer groove is set to 0.1-0.3 mm, so as to match the stress distribution gradient. The edges of the groove walls of the first buffer grooves are all rounded, effectively reducing stress concentration. The groove walls of the first buffer grooves are shot-peened to fill micro-cracks and improve the corrosion resistance of the groove walls at the same time.

[0014] In one or more embodiments of the present invention, honeycomb holes are provided in the protective layer. The honeycomb holes are disposed on the side close to the conductive layer. The honeycomb holes are filled with microcapsules, and a mixture of a corrosion inhibitor and conductive filler is provided in the microcapsules. The side of the protective layer away from the conductive layer is provided with a graphene conductive layer by means of laser cladding. When the battery connection piece is in use, if the surface of the conductive layer is scratched and the anti-corrosion layer is damaged, the damaged anti-corrosion layer can be repaired automatically by the mixture released by the microcapsules, ensuring the anti-corrosion performance of the surface of the conductive layer and ensuring that the connection piece will not undergo electrochemical corrosion when used in a high-temperature and high-humidity environment. The graphene conductive layer can maintain the conductive continuity of the scratched area.

[0015] In one or more embodiments of the present invention, the aperture of the main channel is 30% - 50% of the thickness of the heat dissipation layer, and the ratio between the aperture of the branch channel and the aperture of the main channel is 1:5. The thermally conductive phase change material is paraffin or a graphene composite material, so that the thermally conductive phase change material has good heat absorption performance.

[0016] In one or more embodiments of the present invention, there are at least two of the plurality of second buffer grooves. The depths of the plurality of second buffer grooves are arranged in a manner that gradually increases from the center of the conductive layer to the outside. The depth of the second buffer groove is set to 0.2 - 0.6 mm, so as to be able to match the stress distribution gradient. The edges of the groove walls of the second buffer grooves are all rounded to effectively reduce stress concentration. The groove walls of the second buffer grooves are shot peened to fill microcracks and improve the corrosion resistance of the groove walls at the same time.

[0017] In one or more embodiments of the present invention, a plurality of heat dissipation portions are formed on the top of the heat dissipation layer, and a graphene-based high-radiation coating is coated on the upper surface of the heat dissipation layer. Through the arrangement of the heat dissipation portions and the graphene-based high-radiation coating, the heat dissipation performance of the surface of the heat dissipation layer is effectively improved. At the same time, the graphene-based high-radiation coating has excellent anti-corrosion performance, improving the anti-corrosion property of the surface of the heat dissipation layer.

[0018] In one or more embodiments of the present invention, the conductive layer, the heat dissipation layer, and the insulating layer are all arranged in a matching wavy shape, so that the battery connecting piece of the composite structure is arranged in a wavy shape. The corrugated structure enables the connecting piece to be axially telescopically deformed, relieving the battery expansion stress and effectively avoiding the fracture caused by the hard pulling of the battery connecting piece. When the conductive layer, the heat dissipation layer, and the insulating layer are bonded together, positioning holes are provided at both ends. An anti-corrosion layer is coated on the inner side wall of the positioning hole, and the battery connecting piece of the composite structure is connected to the battery through the positioning hole. The conductive layer is made of copper or copper alloy, so that the conductive layer has excellent electrical conductivity. The heat dissipation layer is made of aluminum or aluminum alloy, so that the heat dissipation layer has excellent heat transfer performance. The insulating layer is made of aluminum nitride, so that the insulating layer has insulating properties, realizing thermoelectric separation, and enabling the heat on the conductive layer to be transferred to the heat dissipation layer through the insulating layer for heat dissipation.

[0019] In one or more embodiments of the present invention, an alumina transition layer is provided between the conductive layer and the insulating layer, and a solder layer is provided between the heat dissipation layer and the insulating layer. The conductive layer and the insulating layer are bonded together through the alumina transition layer, and metallurgical bonding is achieved between the conductive layer and the insulating layer through the alumina transition layer. The heat dissipation layer and the insulating layer are bonded together through the solder layer, and metallurgical bonding is achieved between the heat dissipation layer and the insulating layer through the solder layer.

[0020] A preparation method of a battery connecting piece, the preparation method comprising:

[0021] S1. According to the battery connecting piece to be manufactured, design the corresponding sizes of the conductive layer, the heat dissipation layer, and the insulating layer; since different batteries require different sizes of battery connecting pieces when connected, it is necessary to design the corresponding sizes of the conductive layer, the heat dissipation layer, and the insulating layer on the required composite structure battery connecting piece according to the battery, so as to manufacture according to the designed sizes.

[0022] S2. Cut the blank according to the size of the conductive layer, and then pre-treat the surface of the blank. After pre-treatment, the first buffer grooves are opened at both side edges of the long side of the blank by laser cutting, so that the opening of the first buffer grooves will not affect the structure of the conductive layer. The conductive layer is processed into the required wavy shape by hydraulic forming, so that the bending of the first buffer grooves will not affect its own structure and strength. A protective layer is made at the bottom of the conductive layer. When making the protective layer, first make honeycomb holes at the bottom of the first buffer grooves by 3D printing. Due to the special structure of the honeycomb holes, the efficiency and accuracy of making the honeycomb holes are improved by 3D printing. Microcapsules are filled in the honeycomb holes, and a layer of graphene conductive layer is provided at the bottom of the honeycomb holes by laser cladding, so that the production of the conductive layer can be completed.

[0023] S3. Fabricate the heat dissipation layer by 3D printing according to the designed dimensions of the heat dissipation layer. When fabricating, it is necessary to complete the fabrication of the main channels and branch channels in the shape of leaf veins inside the heat dissipation layer, and fill the main channels with a thermally conductive phase change material. Since the main channels and branch channels need to be fabricated inside the heat dissipation layer, the heat dissipation layer is fabricated by 3D printing, which improves the fabrication efficiency and accuracy of the heat dissipation layer, and can ensure that the strength of the fabricated heat dissipation layer meets the requirements.

[0024] S4. After pretreating the upper and lower side walls of the insulating layer, install the conductive layer at the bottom of the insulating layer by bonding, bond the heat dissipation layer on the top of the insulating layer, complete the fabrication of the main body of the battery connection piece, and then open positioning holes at both ends of the main body, so that the composite mechanism composed of the conductive layer, the heat dissipation layer and the insulating layer forms a stable battery connection piece structure.

[0025] In one or more embodiments of the present invention, the surface of the insulating layer in contact with the conductive layer is pretreated by pre-oxidation to obtain an alumina transition layer, and then a eutectic liquid phase of copper and copper oxide is formed at 1065 - 1083 to chemically react with the alumina layer to generate spinel, realizing the metallurgical bonding between the conductive layer and the insulating layer. After the conductive layer and the insulating layer are bonded, they have excellent thermal conductivity, strong adhesion and high bonding strength, which are suitable for high-frequency and high-current scenarios, but the oxidation process needs to be controlled to avoid a decrease in thermal conductivity caused by an overly thick transition layer. Use a solder of an active metal on the surface of the insulating layer in contact with the heat dissipation layer, and form a TiN transition layer through vacuum brazing at a temperature of about 900 - 1100 under the condition, so that a metallurgical bonding is formed between the heat dissipation layer and the insulating layer, and the bonding strength between the heat dissipation layer and the insulating layer is high while the thermal conductivity is excellent. The conductive layer, the heat dissipation layer and the insulating layer are metallurgically bonded by bonding to ensure the bonding stability of the battery connection piece of the composite structure and the strength during use meet the requirements of use, so that the insulating layer can realize efficient and reliable double-sided metallization connection and meet the requirements of high-power and high-frequency electronic packaging

[0026] When bonding the conductive layer (1) and the insulating layer (3) and the insulating layer (3) and the conductive layer (1) together, it needs to be completed under specific process conditions, so the fabrication cost of the battery connection piece of the composite structure will be increased. Therefore, the technical solution provided in this application is applicable to large-scale production in order to reduce the fabrication cost of the battery connection piece.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. The battery connection piece provided by the present invention is a battery connection piece with a composite structure formed by a conductive layer, a heat dissipation layer, and an insulating layer. The thermoelectric separation of the battery connection piece is achieved through the insulation and heat conductivity of the insulating layer. By isolating heat dissipation, the temperature of the conductive layer is ensured to be stable, thereby reducing the fluctuation of the conductive layer resistance. At the same time, the insulating layer blocks the galvanic corrosion path, effectively extending the service life of the battery connection piece.

[0029] 2. The present invention is provided with a protective layer on the surface of the conductive layer, and microcapsules are filled in the honeycomb holes arranged in the protective layer. When the surface of the battery piece is scratched during use, the mixed material in the microcapsules will be released to repair the scratched anticorrosive layer, ensuring that electrochemical corrosion will not occur when the battery connection piece is used in a high-temperature and high-humidity environment.

[0030] 3. The present invention is provided with a vein-like channel composed of a main channel and a plurality of branch channels in the heat dissipation layer, and a thermally conductive phase change material is arranged in the main channel. When the conductive layer generates serious heat under a large current condition, the heat will quickly be transferred to the heat dissipation layer through the insulating layer. After the thermally conductive phase change material absorbs heat and undergoes a phase change, it flows through the branch channels to achieve active heat dissipation, ensuring the normal temperature of the conductive layer under a large current condition, and thus ensuring the safety of the battery connection piece during use.

[0031] 4. The conductive layer and the insulating layer of the present invention achieve metallurgical bonding through a transition layer, and the heat dissipation layer and the insulating layer achieve metallurgical bonding through a solder layer, so that the bonding strength of the battery connection piece with a composite structure has the strength of an integral structure. Moreover, the battery connection piece with a composite structure is provided with a wavy shape, enabling the connection piece to be axially telescopic, relieving the battery expansion stress, effectively preventing the battery connection piece from being pulled and broken during use, and ensuring the safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is a schematic diagram of a battery connection piece in an embodiment of the present invention;

[0034] Figure 2 It is a three-dimensional view of a battery connection piece in an embodiment of the present invention;

[0035] Figure 3 It is a front sectional view of a battery connection piece in an embodiment of the present invention;

[0036] Figure 4A right-side sectional view of a battery connection piece in an embodiment of the present invention;

[0037] Figure 5 of the present invention Figure 2 A schematic diagram of part A in the present invention;

[0038] Figure 6 A schematic diagram of the conductive plate in the present invention;

[0039] Figure 7 A sectional view of the heat dissipation plate in the present invention;

[0040] Figure 8 of the present invention Figure 7 A schematic diagram of part B in the present invention;

[0041] Figure 9 A partial schematic diagram of the protective layer in the present invention.

[0042] Main reference numeral description:

[0043] 1 - Conductive layer, 11 - First buffer groove, 12 - Protective layer, 13 - Honeycomb holes, 14 - Microcapsules, 15 - Graphene conductive layer, 2 - Heat dissipation layer, 21 - Main channel, 22 - Branch channel, 23 - Thermally conductive phase change material, 24 - Second buffer groove, 25 - Heat dissipation part, 3 - Insulating layer, 4 - Positioning hole. Detailed implementation manners

[0044] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] As Figures 1 to 4 shown, a battery connection piece in an embodiment of the present invention can solve the problems that excessive resistance in the battery connection piece causes heat generation, easy corrosion, and insufficient mechanical strength, which affect the service life and safety of the battery.

[0046] As Figures 1 to 4As shown in the figure, the battery connection piece includes a conductive layer 1 and a heat dissipation layer 2. The conductive layer 1 is disposed at the bottom of the heat dissipation layer 2. An insulating layer 3 is provided between the conductive layer 1 and the heat dissipation layer 2. The conductive layer 1 and the heat dissipation layer 2 are bonded together through the insulating layer 3 to form a battery connection piece with a composite structure. By bonding the conductive layer 1, the heat dissipation layer 2 and the insulating layer 3 together to form a battery connection piece with a composite structure, the structural composition of the traditional integrated electrical connection piece is changed. Since the conductive layer 1 is used for conducting electricity and the heat dissipation layer 2 is used for dissipating heat, and an insulating layer 3 is provided between the conductive layer 1 and the heat dissipation layer 2, due to the insulation and excellent heat conductivity of the insulating layer 3, the separation of heat and electricity of the battery connection piece is realized. High temperature will cause the resistivity of the metal conductive layer to increase, and the thermoelectric separation maintains the temperature of the conductive layer 1 stable by isolating heat dissipation, reducing the range of resistance fluctuation of the conductive layer 1; the conductive layer 1 and the heat dissipation layer 2 are isolated by the insulating layer 3, blocking the path of galvanic corrosion and prolonging the service life of the battery connection piece; at the same time, the insulating layer 3 can withstand high voltage, avoiding the risk of leakage current or short circuit, especially suitable for high-voltage battery systems, and the insulating layer 3 can suppress abnormal discharge, reducing the probability of thermal runaway of the battery cell.

[0047] As Figures 1 to 4 shown, a protective layer 12 is integrally formed at the bottom of the conductive layer 1. The protective layer 12 is used to protect the surface of the conductive layer 1, preventing the conductive layer 1 from being corroded during use. At the same time, when the surface of the conductive layer 1 is scratched, self-repair of the anti-corrosion layer can be carried out to ensure that electrochemical corrosion does not occur when the connection piece is used in a high-temperature and high-humidity environment.

[0048] As Figure 3 、 Figure 7 and Figure 8 shown, a main channel 21 is formed in the heat dissipation layer 2 along the long side direction. A plurality of branch channels 22 are formed on both sides of the main channel 21 in a communicating manner. The main channel 21 and the plurality of branch channels 22 form a vein-like channel. A heat-conducting phase-change material 23 is filled in the main channel 21. When local heating of the battery cell is severe under high-current conditions, the heat on the conductive layer 1 will be quickly transferred to the heat dissipation layer 2 through the insulating layer 3. The heat-conducting phase-change material 23 in the main channel 21 will quickly and efficiently absorb heat. After the heat-conducting phase-change material 23 absorbs heat and undergoes a phase change, it will flow in the plurality of branch channels 22, so that the heat-conducting phase-change material 23 can flow in the form of a vein-like microchannel after absorbing heat, realizing active heat dissipation, thus effectively avoiding the overheating of the local temperature of the insulating layer 3 under high-current conditions, ensuring the normal temperature on the surface of the insulating layer 3 under high-current conditions, and thus ensuring the safety of the battery connection piece during use. When the current drops and the temperature of the heat-conducting phase-change material 23 decreases, the heat-conducting phase-change material 23 solidifies after cooling, realizing self-repair of the structure, enabling the heat-conducting phase-change material 23 to be reused, and ensuring the cooling effect of the heat-conducting phase-change material 23 on the insulating layer 3 under high-current conditions.

[0049] AsFigures 3 to 5 As shown, a plurality of second buffer grooves 24 are provided on both sides of the heat dissipation layer 2 located at the long edges, so that the second buffer grooves 24 are provided at the long edge of the battery connection piece of the composite structure, effectively improving the anti-vibration fatigue performance of the battery connection piece and absorbing the lateral stress generated by the expansion of the battery during charge and discharge.

[0050] As Figures 4 to 6 shown, a plurality of first buffer grooves 11 are provided on both sides of the conductive layer 1 located at the long edges, effectively improving the anti-vibration fatigue performance of the conductive layer 1 and absorbing the lateral stress generated by the expansion of the battery during charge and discharge. At least two of the plurality of first buffer grooves 11 are provided, and the depths of the plurality of first buffer grooves 11 are arranged in a manner of gradually increasing from the center of the conductive layer 1 to the outside. The depth of the first buffer groove 11 is set to 0.1 - 0.3 mm, so as to match the stress distribution gradient. The edges of the groove walls of the first buffer grooves 11 are all rounded to effectively reduce stress concentration. The groove walls of the first buffer grooves 11 are shot-peened to fill microcracks and improve the corrosion resistance of the groove walls at the same time.

[0051] Optionally, the first buffer grooves 11 can be selected according to the actual structure of the conductive layer 1. If opening the first buffer grooves 11 on the conductive layer 1 affects the electrical conductivity of the conductive layer 1, then the first buffer grooves 11 are not opened at the side wall edges of the conductive layer 1.

[0052] As Figure 4 and Figure 9 shown, honeycomb holes 13 are provided in the protective layer 12, and the honeycomb holes 13 are provided on the side close to the conductive layer 1. Microcapsules 14 are filled in the honeycomb holes 13, and a mixture of a corrosion inhibitor and a conductive filler is provided in the microcapsules 14. A graphene conductive layer 15 is provided on the side of the protective layer 12 away from the conductive layer 1 by means of laser cladding. When the battery connection piece is in use, if the surface of the conductive layer 1 is scratched and the anti-corrosion layer is damaged, the damaged anti-corrosion layer can be repaired by itself through the mixture released by the microcapsules 14, ensuring the anti-corrosion performance of the surface of the conductive layer 1 and ensuring that electrochemical corrosion does not occur when the connection piece is used in a high-temperature and high-humidity environment. The graphene conductive layer 15 can maintain the electrical conductivity continuity of the scratched area.

[0053] Preferably, the aperture of the main channel 21 is 30% - 50% of the thickness of the heat dissipation layer 2, and the ratio between the aperture of the branch channel 22 and the aperture of the main channel 21 is 1:5. The thermally conductive phase change material 23 is made of paraffin or a graphene composite material, so that the thermally conductive phase change material 23 has good heat absorption performance.

[0054] As Figure 2 Combined Figure 4As shown, there are at least two of the multiple second buffer grooves 24. The depths of the multiple second buffer grooves 24 are set in a way that gradually increases from the center of the conductive layer 1 to the outside. The depth of the second buffer groove 24 is set to 0.2 - 0.6 mm, so as to be able to match the stress distribution gradient. The edges of the groove walls of the second buffer groove 24 are all rounded to effectively reduce stress concentration. The groove walls of the second buffer groove 24 are shot peened to fill microcracks and improve the corrosion resistance of the groove walls at the same time.

[0055] As Figure 2 shown, multiple heat dissipation parts 25 are formed on the top of the heat dissipation layer 2. The upper surface of the heat dissipation layer 2 is coated with a graphene-based high-radiation coating. Through the settings of the heat dissipation parts 25 and the graphene-based high-radiation coating, the heat dissipation performance of the surface of the heat dissipation layer 2 is effectively improved. At the same time, the graphene-based high-radiation coating has excellent corrosion resistance, improving the corrosion resistance of the surface of the heat dissipation layer 2.

[0056] As Figures 1 to 3 shown, the conductive layer 1, the heat dissipation layer 2, and the insulating layer 3 are all set to be matching wavy shapes, so that the battery connection piece of the composite structure is set to be wavy. The corrugated structure enables the connection piece to be axially stretchable and deformable, relieving the battery expansion stress and effectively avoiding the fracture caused by the hard pulling of the battery connection piece. At the same time, the corrugated structure extends the actual conduction path of the conductive layer 1, and it is necessary to maintain the resistivity by increasing the thickness of the conductive layer 1 or increasing the corrugation density. When the conductive layer 1, the heat dissipation layer 2, and the insulating layer 3 are bonded together, positioning holes 4 are opened at both ends. An anti-corrosion layer is coated on the inner side wall of the positioning hole 4. The battery connection piece of the composite structure is connected to the battery through the positioning hole 4. The conductive layer 1 is made of copper or copper alloy, so that the conductive layer 1 has excellent electrical conductivity. The heat dissipation layer 2 is made of aluminum or aluminum alloy, so that the heat dissipation layer 2 has excellent heat transfer performance. The insulating layer 3 is made of aluminum nitride, so that the insulating layer 3 has excellent insulation performance and excellent heat conduction performance at the same time, realizing thermoelectric separation, and enabling the heat on the conductive layer 1 to be transferred to the heat dissipation layer 2 through the insulating layer 3 for heat dissipation. Since the conductive layer 1, the heat dissipation layer 2, and the insulating layer 3 are set to be wavy, the contact area between them is effectively increased, thereby improving the heat transfer effect and avoiding the accumulation of heat on the conductive layer 1, ensuring the normal temperature of the conductive layer 1 during use.

[0057] Preferably, an alumina transition layer is provided between the conductive layer 1 and the insulating layer 3, and a solder layer is provided between the heat dissipation layer 2 and the insulating layer 3. The conductive layer 1 and the insulating layer 3 are bonded together through the alumina transition layer, and metallurgical bonding is achieved between the conductive layer 1 and the insulating layer 3 through the alumina transition layer. The heat dissipation layer 2 and the insulating layer 3 are bonded together through the solder layer, and metallurgical bonding is achieved between the heat dissipation layer 2 and the insulating layer 3 through the solder layer. Through the bonding method, metallurgical bonding is achieved between the conductive layer 1 and the insulating layer 3 and between the insulating layer 3 and the heat dissipation layer 2, so that the bonding strength of the battery connection piece with a composite structure composed of the conductive layer 1, the heat dissipation layer 2, and the insulating layer 3 has the strength of an integral battery connection piece.

[0058] Optionally, the thickness ratio among the conductive layer 1, the heat dissipation layer 2, and the insulating layer 3 is preferably 1:2.5:0.5, and can be appropriately adjusted according to the specific battery cells during actual production.

[0059] It should be noted that the battery connection piece with a composite structure provided in this application is applicable to various structural battery connection pieces, and can be manufactured by designing and improving according to the specific structure during production.

[0060] A preparation method of a battery connection piece, the preparation method includes:

[0061] S1. According to the battery connection piece to be manufactured, design the corresponding sizes of the conductive layer 1, the heat dissipation layer 2, and the insulating layer 3; since different batteries require different sizes of battery connection pieces during connection, it is necessary to design the corresponding sizes of the conductive layer 1, the heat dissipation layer 2, and the insulating layer 3 on the required composite structure battery connection piece according to the battery, so as to manufacture according to the designed sizes.

[0062] S2. Cut the blank according to the size of the conductive layer 1, and then pre-treat the surface of the blank. After pre-treatment, the first buffer groove 11 is opened at both side edges of the long side of the blank by laser cutting, so that the opening of the first buffer groove 11 will not affect the structure of the conductive layer 1. The conductive layer 1 is processed into the required wavy shape by hydraulic forming, so that the bending of the first buffer groove 11 during production will not affect its own structure and strength. A protective layer 12 is made at the bottom of the conductive layer 1. When making the protective layer 12, first, the honeycomb holes 13 are made at the bottom of the first buffer groove 11 by 3D printing. Due to the special structure of the honeycomb holes 13, the efficiency and accuracy of making the honeycomb holes 13 are improved by 3D printing. After filling the microcapsules 14 into the honeycomb holes 13, a layer of graphene conductive layer 15 is provided at the bottom of the honeycomb holes 13 by laser cladding, and thus the production of the conductive layer 1 can be completed.

[0063] S3. Fabricate the heat dissipation layer 2 by 3D printing according to the designed dimensions of the heat dissipation layer 2. When fabricating, it is necessary to complete the fabrication of the main channels 21 and branch channels 22 in the shape of imitation leaf veins inside the heat dissipation layer 2, and fill the main channels 21 with a thermally conductive phase change material 23. Since the main channels 21 and branch channels 22 need to be fabricated inside the heat dissipation layer 2, the heat dissipation layer 2 is fabricated by 3D printing, which improves the fabrication efficiency and accuracy of the heat dissipation layer 2, and can ensure that the strength of the fabricated heat dissipation layer 2 meets the requirements.

[0064] S4. After preprocessing the upper and lower side walls of the insulating layer 3, install the conductive layer 1 at the bottom of the insulating layer 3 by bonding, and bond the heat dissipation layer 2 on the top of the insulating layer 3 to complete the fabrication of the battery connection piece body. Then, open positioning holes 4 at both ends of the body, so that the battery connection piece structure of the composite mechanism composed of the conductive layer 1, the heat dissipation layer 2 and the insulating layer 3 is stable.

[0065] Specifically, the surface of the insulating layer 3 in contact with the conductive layer 1 is pretreated by pre-oxidation to obtain an alumina transition layer. Subsequently, a eutectic liquid phase of copper and copper oxide is formed at 1065 - 1083 to chemically react with the alumina layer to generate spinel, realizing the metallurgical bonding between the conductive layer 1 and the insulating layer 3. After the conductive layer 1 and the insulating layer 3 are bonded, they have excellent thermal conductivity, strong adhesion and high bonding strength, and are suitable for use in high-frequency and high-current scenarios. During fabrication, the oxidation process needs to be controlled to avoid a decrease in thermal conductivity caused by an overly thick transition layer. On the surface of the insulating layer 3 in contact with the heat dissipation layer 2, an active metal solder is used, and a TiN transition layer is formed by vacuum brazing at a temperature of about 900 - 1100 to form a metallurgical bonding between the heat dissipation layer 2 and the insulating layer 3, so that the bonding strength between the heat dissipation layer 2 and the insulating layer 3 is high and the thermal conductivity is excellent at the same time. At the same time, when performing vacuum brazing at high temperature, the temperature acts on the surfaces of the heat dissipation layer and the insulating layer, avoiding the influence of ultra-high temperature on the performance of the thermally conductive phase change material 23 in the heat dissipation layer 2. The conductive layer 1, the heat dissipation layer 2 and the insulating layer 3 are metallurgically bonded by bonding to ensure the bonding stability of the battery connection piece of the composite structure and the strength during use meet the requirements of use, enabling the insulating layer 3 to achieve efficient and reliable double-sided metallization connection and meeting the requirements of high-power and high-frequency electronic packaging.

[0066] When bonding the conductive layer 1 and the insulating layer 3 and the insulating layer 3 and the conductive layer 1 together, it needs to be completed under specific process conditions, so the fabrication cost of the battery connection piece of the composite structure will be increased. Therefore, the technical solution provided in this application is applicable to large-scale production in order to reduce the fabrication cost of the battery connection piece.

[0067] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0068] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard 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.

Claims

1. A battery connection piece, characterized in that, It includes a conductive layer and a heat dissipation layer. The conductive layer is disposed at the bottom of the heat dissipation layer. An insulating layer is provided between the conductive layer and the heat dissipation layer. The conductive layer and the heat dissipation layer are bonded together through the insulating layer to form a battery connection piece with a composite structure. A protective layer is integrally formed at the bottom of the conductive layer. A main channel is formed in the heat dissipation layer along the long side direction. A plurality of branch channels are provided on both sides of the main channel in a communicating manner. The main channel and the plurality of branch channels form a vein-like channel. The main channel is filled with a thermally conductive phase change material. A plurality of second buffer grooves are provided on both sides of the heat dissipation layer located at the long edges; Honeycomb holes are provided in the protective layer. The honeycomb holes are disposed on the side close to the conductive layer. The honeycomb holes are filled with microcapsules. A mixed material of a corrosion inhibitor and a conductive filler is provided in the microcapsules. A graphene conductive layer is provided on the side of the protective layer away from the conductive layer by laser cladding; An alumina transition layer is provided between the conductive layer and the insulating layer. A solder layer is provided between the heat dissipation layer and the insulating layer. The conductive layer and the insulating layer are bonded together through the alumina transition layer. The heat dissipation layer and the insulating layer are bonded together through the solder layer.

2. The battery connecting piece according to claim 1, characterized in that, A plurality of first buffer grooves are provided on both sides of the conductive layer located at the long edges. At least two of the plurality of first buffer grooves are provided. The depths of the plurality of first buffer grooves are set in a manner that gradually increases from the center of the conductive layer to the outside. The depth of the first buffer groove is set to 0.1 - 0.3 mm. The edges of the groove walls of the first buffer groove are all rounded. The groove walls of the first buffer groove are shot peened.

3. A battery connection piece according to claim 1, characterized in that, The aperture of the main channel is 30% - 50% of the thickness of the heat dissipation layer. The ratio between the aperture of the branch channel and the aperture of the main channel is 1:

5. The thermally conductive phase change material is paraffin or a graphene composite material.

4. The battery connecting piece according to claim 1, wherein, At least two of the plurality of second buffer grooves are provided. The depths of the plurality of second buffer grooves are set in a manner that gradually increases from the center of the conductive layer to the outside. The depth of the second buffer groove is set to 0.2 - 0.6 mm. The edges of the groove walls of the second buffer groove are all rounded. The groove walls of the second buffer groove are shot peened.

5. A battery connection piece according to claim 1, characterized in that A plurality of heat dissipation parts are formed on the top of the heat dissipation layer. The upper surface of the heat dissipation layer is coated with a graphene-based high-radiation coating.

6. The battery connecting piece according to claim 1, characterized in that, The conductive layer, the heat dissipation layer, and the insulating layer are all set to be matching wavy shapes. When the conductive layer, the heat dissipation layer, and the insulating layer are bonded together, positioning holes are provided at both ends. An anti-corrosion layer is coated on the inner side wall of the positioning hole. The conductive layer is made of copper or a copper alloy. The heat dissipation layer is made of aluminum or an aluminum alloy. The insulating layer is made of aluminum nitride.

7. A preparation method of a battery connecting piece, which is used for the preparation of a battery connecting piece according to any one of claims 1 to 6, characterized in that, The preparation method includes: S1. According to the battery connection piece to be manufactured, design the corresponding dimensions of the conductive layer, the heat dissipation layer, and the insulating layer; S2. Cut the blank according to the size of the conductive layer, and then pre-treat the surface of the blank. The pre-treated blank is processed by laser cutting to form the first buffer grooves at both side edges of the long side, and the conductive layer is processed into the required wavy shape by hydroforming, and then a protective layer is made at the bottom of the conductive layer; S3. Fabricate the heat dissipation layer by 3D printing according to the designed size of the heat dissipation layer. When fabricating, it is necessary to complete the fabrication of the main channels and branch channels of the vein-like channels inside the heat dissipation layer, and fill the main channels with a thermally conductive phase change material; S4. After pre-treating the upper and lower side walls of the insulating layer, the conductive layer is installed at the bottom of the insulating layer by bonding, and the heat dissipation layer is bonded to the top of the insulating layer to complete the fabrication of the battery connection piece body, and then positioning holes are drilled at both ends of the body; Specifically, the surface of the insulating layer in contact with the conductive layer is pre-oxidized to obtain an alumina transition layer, and then a eutectic liquid phase of copper and copper oxide is formed at 1065-1083 °C, which reacts chemically with the alumina layer to generate spinel, realizing the metallurgical bonding between the conductive layer and the insulating layer; on the surface of the insulating layer in contact with the heat dissipation layer, a solder of an active metal is used, and a TiN transition layer is formed by vacuum brazing at a temperature of 900-1100 °C, so that a metallurgical bonding is formed between the heat dissipation layer and the insulating layer.

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