Battery connection chip, battery module, battery pack and electric device

Abstract

The invention relates to the technical field of batteries, in particular to a battery connecting piece, a battery module, a battery pack and a power utilization device.The battery connecting piece comprises a piece body, and the piece body comprises a first electric conductor, a middle body and a second electric conductor which are sequentially connected in the length direction; the first electric conductor and the second electric conductor are electrically connected with the poles of the two single batteries respectively; the intermediate is a thermosensitive conductive material, and the intermediate is in a conductive state in response to the situation that the ambient temperature around the chip body is smaller than the Curie temperature of the thermosensitive conductive material; and when the ambient temperature around the chip body is greater than or equal to the Curie temperature of the thermosensitive conductive material, the intermediate is in an insulated state. When the short circuit of the battery system is identified, the circuit is automatically disconnected, and the active protection of the internal circuit of the battery module is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a battery connection tab, a battery module, a battery pack, and an electrical device. Background Art

[0002] At present, with the booming development of the electric vehicle industry, which has brought great convenience to people's lives, at the same time, people have paid more attention to the safety performance of electric vehicles. As the core component of the three-electric system of new energy vehicles, the structural design, performance, and safety status of power batteries all have a direct and crucial impact on the performance of electric vehicles. Among them, the thermal safety issue of electric vehicles and battery modules is the top priority of battery system safety.

[0003] Nowadays, in the process of technological development of electric vehicles, the pursuit of high energy density and lightweight is synchronized, which requires highly integrated components in the entire battery system. And this trend of integration makes the safety protection scheme become increasingly complex, and the cost also increases significantly accordingly.

[0004] In related prior arts, the power battery safety protection schemes are mainly divided into two categories. One is to achieve the protection purpose by means of external protection units and systems. Although this method can achieve basic protection functions, it is difficult to adapt to the new generation of highly integrated and lightweight battery systems. The other is to conduct protection by setting safety busbars or fuses. However, this method can only protect the external circuit at the battery pack level when the battery gets out of control, and the safety problem of the internal circuit of the battery cell module still fails to be effectively solved. Once a short circuit occurs, the heat generated by the ultra-high current will be conducted to the battery cells through the internal circuit, thereby triggering a thermal runaway phenomenon. Summary of the Invention

[0005] The purpose of the present invention is to provide a battery connection tab, a battery module, a battery pack, and an electrical device, which can autonomously disconnect the circuit when a short circuit in the battery system is recognized, and achieve active protection of the internal circuit of the battery module.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention discloses a battery connection tab, including a tab body. The tab body includes a first conductor, an intermediate body, and a second conductor that are sequentially connected along the length direction. The first conductor and the second conductor are respectively electrically connected to the pole columns of two battery cells; the intermediate body is a thermosensitive conductive material. In response to the ambient temperature around the tab body being less than the Curie temperature of the thermosensitive conductive material, the intermediate body is in a conductive state; in response to the ambient temperature around the tab body being greater than or equal to the Curie temperature of the thermosensitive conductive material, the intermediate body is in an insulating state.

[0007] Further, the intermediate includes a first encapsulation layer, a functional layer, and a second encapsulation layer stacked in sequence along the thickness direction. The two ends of the functional layer in the length direction are respectively in contact and cooperation with the first conductor and the second conductor; The functional layer is filled with thermosensitive conductive particles, and the thermosensitive conductive particles include conductive microparticles and a thermosensitive conductive polymer shell wrapped on the surface of the conductive microparticles; in response to the ambient temperature around the bar body being less than the Curie temperature of the thermosensitive conductive polymer shell, the functional layer is in a conductive state; in response to the ambient temperature around the bar body being greater than or equal to the Curie temperature of the thermosensitive conductive polymer shell, the functional layer is in an insulating state.

[0008] Further, the materials of the first encapsulation layer and the second encapsulation layer are polyimide, polyether ether ketone, or liquid crystal polymer; the material of the conductive microparticles is conductive metal.

[0009] Further, the thermosensitive conductive polymer shell includes a thermally expandable polymer matrix and conductive fillers uniformly dispersed in the thermally expandable polymer matrix; in response to the ambient temperature around the bar body being less than the Curie temperature of the thermosensitive conductive polymer shell, the conductive fillers are connected to each other to form a conductive channel, making the functional layer in a conductive state; in response to the ambient temperature around the bar body being greater than or equal to the Curie temperature of the thermosensitive conductive polymer shell, the thermally expandable polymer matrix expands, the conductive fillers are separated, and the conductive channel is cut off, making the functional layer in an insulating state.

[0010] Further, the material of the polymer matrix is polyethylene, polypropylene, polyvinyl chloride, or thermoplastic polyurethane; the material of the conductive fillers is conductive metal nanoparticles, carbon nanotubes, carbon black particles, or polythiophene.

[0011] Further, at least one of the two side surfaces of the bar body in the thickness direction is connected with a phase change material plate, and the phase change material plate can cover the intermediate in the thickness direction of the bar body.

[0012] Further, the Curie temperature of the phase change material plate is less than the Curie temperature of the thermosensitive conductive material.

[0013] In a second aspect, the present invention discloses a battery module, which includes: A plurality of battery cells, the plurality of battery cells are arranged side by side, and each of the battery cells includes two pole columns with opposite electrode polarities; The above-mentioned battery connection bar, the first conductor and the second conductor of the battery connection bar are respectively electrically connected to the pole columns of two adjacent battery cells.

[0014] In a third aspect, the present invention discloses a battery pack, including the above-mentioned battery module.

[0015] Fourthly, the present invention discloses an electrical device, including the above-mentioned battery pack, and the battery pack is used to supply power to the electrical device.

[0016] The present invention has the following unexpected beneficial effects: 1. The intermediate of the present invention is a thermosensitive conductive material. During the operation of the battery system, once a short circuit occurs, a large amount of heat will be generated by the short-circuit current, causing the ambient temperature around the barium piece body to rise rapidly. When the temperature reaches the Curie temperature of the thermosensitive conductive material, the intermediate changes from the conductive state to the insulating state, automatically disconnecting the circuit, and thus can timely prevent the short-circuit current from continuously passing through, avoiding serious safety problems such as thermal runaway caused by the long-time passage of large current in the internal circuit of the battery module, realizing the active protection of the internal circuit of the battery module, effectively ensuring the safe operation of the battery system. At the same time, it avoids the damage to the internal structure and chemical substances of the battery caused by the high heat generated by the short-circuit current, helps to maintain the performance stability of the battery cell, and extends the service life of the battery. Overall, it improves the stability and reliability of the battery system, and reduces the maintenance and replacement costs caused by battery failures.

[0017] 2. The battery connection barium piece of the present invention directly serves as a battery connection component, integrating the thermosensitive conductive material at the intermediate position of the barium piece body. There is no need for additional complex external protection units and systems. The structure is simple and compact, and it can be well integrated into the highly integrated battery system, meeting the requirements of integration without increasing excessive space occupation and system complexity, and helping to improve the integration degree and reliability of the entire battery system.

[0018] 3. The thermosensitive conductive material of the present invention responds rapidly to temperature changes and can change its conductive performance according to temperature changes in an extremely short time. Once the ambient temperature around the barium piece body reaches the Curie temperature, the intermediate can quickly change from the conductive state to the insulating state, disconnecting the circuit and timely preventing the further harm of the short-circuit current, effectively improving the ability of the battery system to cope with sudden short-circuit conditions and enhancing the safety and stability of the battery system. Description of the Drawings

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in 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 in the following description are only some embodiments of the present invention.

[0020] Figure 1 Shows the structural schematic diagram of the battery connection barium piece provided by the embodiment of the present invention.

[0021] Figure 2 Shows the structural schematic diagram of the thermosensitive conductive particles provided by the embodiment of the present invention.

[0022] Figure 3 The schematic diagram of the state of the thermosensitive conductive polymer housing provided by the embodiment of the present invention at different temperatures is shown.

[0023] Figure 4 The schematic connection diagram of the battery connection tab and the battery cell provided by the embodiment of the present invention is shown.

[0024] Figure 5 The top view of the connection between the battery connection tab and the battery cell provided by the embodiment of the present invention is shown.

[0025] Figure 6 Shown is Figure 5 The schematic sectional view at A-A in

[0026] In the figure, 1 - the first conductor, 2 - the second conductor, 3 - the intermediate body, 31 - the first encapsulation layer, 32 - the second encapsulation layer, 33 - the functional layer, 34 - the thermosensitive conductive particles, 341 - the conductive microparticles, 342 - the thermosensitive conductive polymer housing, 3421 - the polymer matrix, 3422 - the conductive filler; 4 - the phase change material plate; 5 - the battery cell, 51 - the terminal post; 6 - the gasket. Specific embodiments

[0027] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the protection scope of the present invention.

[0028] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. The components shown in the drawings only show the components related to the present invention and are not drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0029] In one embodiment, refer to Figure 1 、 Figures 4 to 6As shown in the figure, the present invention provides a battery connection tab, which includes a tab body. The tab body includes a first conductor 1, an intermediate body 3, and a second conductor 2 that are sequentially connected along the length direction. The first conductor 1 and the second conductor 2 are respectively electrically connected to the electrode posts 51 of two battery cells 5. The intermediate body 3 is a thermosensitive conductive material. In response to the ambient temperature around the tab body being lower than the Curie temperature of the thermosensitive conductive material, the intermediate body 3 is in a conductive state; in response to the ambient temperature around the tab body being greater than or equal to the Curie temperature of the thermosensitive conductive material, the intermediate body 3 is in an insulating state.

[0030] Short circuit is one of the important factors affecting the battery life. The large current and high heat generated by the short circuit will cause irreversible damage to the internal structure and chemical substances of the battery. Since the intermediate body 3 of the present invention is a thermosensitive conductive material, during the operation of the battery system, once a short circuit occurs, the short-circuit current will generate a large amount of heat, causing the ambient temperature around the tab body to rise rapidly. When the temperature reaches the Curie temperature of the thermosensitive conductive material, the intermediate body 3 changes from a conductive state to an insulating state, automatically disconnecting the circuit, and thus being able to timely prevent the short-circuit current from continuously passing through, avoiding serious safety problems such as thermal runaway caused by the internal circuit of the battery module passing through a large current for a long time, achieving active protection of the internal circuit of the battery module, and effectively ensuring the safe operation of the battery system. At the same time, it avoids the damage to the internal structure and chemical substances of the battery caused by the high heat generated by the short-circuit current, helps to maintain the performance stability of the battery cell, and extends the service life of the battery. Overall, it improves the stability and reliability of the battery system and reduces the maintenance and replacement costs caused by battery failures.

[0031] The battery connection tab of the present invention directly serves as a battery connection component, integrating the thermosensitive conductive material at the position of the intermediate body 3 of the tab body. Without additional complex external protection units and systems, the structure is simple and compact, and it can be well integrated into a highly integrated battery system, meeting the requirements of integration without increasing excessive space occupation and system complexity, and helping to improve the integration and reliability of the entire battery system.

[0032] The thermosensitive conductive material of the present invention responds quickly to temperature changes and can change its conductive performance according to temperature changes in a very short time. Once the ambient temperature around the tab body reaches the Curie temperature, the intermediate body 3 can quickly change from a conductive state to an insulating state, disconnecting the circuit and timely preventing further harm from the short-circuit current, effectively improving the ability of the battery system to cope with sudden short-circuit conditions and enhancing the safety and stability of the battery system.

[0033] Furthermore, the Curie temperature of the thermosensitive conductive material can be adjusted in the following ways: 1. Adjust the Curie temperature by changing the chemical composition of the material, adding additives in different proportions, etc. For example, when synthesizing a temperature-sensitive conductive polymer material, adjusting the types and ratios of monomers may enable the regulation of the Curie temperature so that the battery connection tab can be suitable for the thermal management requirements of different battery systems.

[0034] 2. During the material preparation process, controlling process parameters such as the crystallinity, heat treatment temperature, and time of the material may change the microstructure of the material, thereby adjusting the Curie temperature. For example, annealing the thermosensitive conductive material at different temperatures and durations causes changes in its internal structure, ultimately changing the Curie temperature.

[0035] As a preferred embodiment of the present invention, see Figure 1 and Figure 6 As shown, the intermediate 3 includes a first encapsulation layer 31, a functional layer 33, and a second encapsulation layer 32 stacked in sequence along the thickness direction. Both ends of the functional layer 33 in the length direction are in contact and cooperation with the first conductor 1 and the second conductor 2 respectively. The functional layer 33 is filled with thermosensitive conductive particles 34. As shown in Figure 2 The thermosensitive conductive particles 34 include conductive microparticles 341 and a thermosensitive conductive polymer shell 342 wrapped around the surface of the conductive microparticles 341. In response to the temperature of the environment around the tab body being less than the Curie temperature of the thermosensitive conductive polymer shell 342, the functional layer 33 is in a conductive state. In response to the temperature of the environment around the tab body being greater than or equal to the Curie temperature of the thermosensitive conductive polymer shell 342, the functional layer 33 is in an insulating state.

[0036] At normal operating temperatures, that is, when the temperature of the environment around the tab body is less than the Curie temperature of the thermosensitive conductive polymer shell 342, the thermosensitive conductive polymer shell is in a conductive state, enabling the conductive microparticles 341 to be connected to form a conductive path. The functional layer 33 can smoothly conduct current, ensuring the normal electrical connection between battery cells 5 and maintaining the stable operation of the battery system. When the temperature reaches or exceeds the Curie temperature, the thermosensitive conductive polymer shell 342 quickly changes to an insulating state, cutting off the connection between the conductive microparticles 341. The functional layer 33 then becomes an insulating state, reliably disconnecting the circuit, timely preventing abnormal current, and avoiding safety accidents such as thermal runaway of the battery module, providing reliable safety protection for the battery system.

[0037] The intermediate 3 adopts a structure in which a first encapsulation layer 31, a functional layer 33, and a second encapsulation layer 32 are stacked in sequence, providing an all-round protection for the functional layer 33. The first encapsulation layer 31 and the second encapsulation layer 32 can effectively prevent external environmental factors, such as moisture, dust, corrosive gases, etc., from eroding the thermosensitive conductive particles 34 in the functional layer 33, ensuring the stable performance of the thermosensitive conductive particles 34 and extending the service life of the battery connection tab. During the assembly and use of the battery module, the first encapsulation layer 31 and the second encapsulation layer 32 can also buffer the impact and friction of external forces on the functional layer 33, avoiding damage to the functional layer 33, ensuring its normal operation, and thus improving the reliability of the entire battery connection tab.

[0038] In this preferred embodiment, by adjusting parameters such as the material, size, shape of the conductive microparticles 341 in the thermosensitive conductive particles 34 and the chemical composition, thickness of the thermosensitive conductive polymer shell 342, the conductive performance and Curie temperature of the functional layer 33 can be flexibly adjusted, enabling the battery connection tab to better adapt to different types of battery cells and the diverse requirements of battery systems. For battery systems with different energy densities and different operating temperature ranges, thermosensitive conductive particles 34 with specific parameters can be customized to optimize the performance of the battery connection tab and enhance its adaptability and stability under various working conditions.

[0039] As a preferred embodiment of the present invention, the materials of the first encapsulation layer 31 and the second encapsulation layer 32 are polyimide, polyether ether ketone or liquid crystal polymer.

[0040] Polyimide (PI) has outstanding high-temperature resistance, and its long-term use temperature can reach above 200 °C. It can maintain stable physical and chemical properties in the high-temperature environment generated during battery operation, and will not deform, decompose or lose its insulation performance due to high temperature, providing reliable thermal protection for the functional layer 33 and ensuring that the thermosensitive conductive particles 34 can still operate normally at high temperatures. At the same time, polyimide has excellent insulation performance, with a low dielectric constant, which can effectively prevent leakage between the functional layer and the external environment, ensuring the electrical insulation and safety of the battery connection tab. In addition, polyimide also has good mechanical properties, with a relatively high tensile strength, and can withstand the external forces during the assembly and use of the battery module, protecting the functional layer 33 from damage.

[0041] The high-temperature resistance of polyether ether ketone (PEEK) is more excellent, enabling the battery connection tab to operate stably even in extremely high-temperature environments, greatly broadening the operating temperature range of the battery system. It has extremely high mechanical strength, with a tensile strength of up to 100 - 130 MPa, excellent wear resistance and impact resistance. When the battery module is vibrated or squeezed, it can effectively protect the functional layer 33, preventing the displacement or damage of the thermosensitive conductive particles 34 due to external forces, thus maintaining the normal function of the battery connection tab. Moreover, polyether ether ketone has strong chemical stability and good corrosion resistance, capable of resisting the erosion of chemical substances such as the electrolyte inside the battery, and extending the service life of the battery connection tab.

[0042] Liquid crystal polymer (LCP) has an extremely low dielectric constant and dielectric loss. In a high-frequency environment, it can effectively reduce signal transmission loss, ensuring the stable electrical performance of the battery connection tab, which is crucial for some battery systems with high requirements for the quality of electrical signal transmission. Liquid crystal polymer has good fluidity and is easy to process and form, enabling the encapsulation of complex shapes, better fitting the functional layer 33 of the intermediate body 3 and the tab body structure, and improving the tightness and integrity of the encapsulation. In addition, liquid crystal polymer also has good flame retardancy, with an oxygen index as high as 35 - 42%. When the battery experiences abnormal overheating or even catches fire, it can delay the spread of the fire and improve the safety of the battery system.

[0043] As a preferred embodiment of the present invention, the material of the conductive particle 341 is a conductive metal.

[0044] Common conductive metals such as silver and copper have extremely high electrical conductivities. The electrical conductivity of silver can reach 6.3×10 7 S / m, and the electrical conductivity of copper is approximately 5.9×10 7 S / m. Using these conductive metals as the material of the conductive particles can effectively reduce the resistance of the battery connection tab, reduce the energy loss during current transmission, and improve the charge and discharge efficiency of the battery system. When the battery module is working, a large current can pass through the conductive particles quickly and stably, ensuring the full performance of the battery.

[0045] Conductive metals are relatively chemically stable under normal battery operating conditions. Although copper is easily oxidized in air, in this embodiment, the conductive particle 341 is encapsulated in the thermosensitive conductive polymer shell 342 and protected by the encapsulation layer, which can effectively prevent oxidation and ensure long-term stable conductive performance. This stability enables the battery connection tab to not experience a significant decline in conductive performance during long-term use, ensuring the reliability and service life of the battery system.

[0046] Conductive metals generally have good processability and can be easily made into conductive particles of various shapes and sizes, which can better meet the filling requirements of the functional layer. For example, metals can be processed into nano-scale or micro-scale particles by physical or chemical methods to increase their specific surface area and improve the contact area with the thermosensitive conductive polymer shell 342, further optimizing the conductive performance and temperature response characteristics.

[0047] As a preferred embodiment of the present invention, refer to Figure 3 As shown, the thermosensitive conductive polymer shell 342 includes a thermally expandable polymer matrix 3421 and conductive fillers 3422 uniformly dispersed in the thermally expandable polymer matrix 3421. In response to the ambient temperature around the tab body being less than the Curie temperature of the thermosensitive conductive polymer shell 342, the conductive fillers 3422 are connected to each other to form a conductive channel, making the functional layer 33 in a conductive state; in response to the ambient temperature around the tab body being greater than or equal to the Curie temperature of the thermosensitive conductive polymer shell 342, the thermally expandable polymer matrix 3421 expands, and the conductive fillers 3422 are separated, cutting off the conductive channel, making the functional layer 33 in an insulating state.

[0048] The thermally expandable polymer matrix 3421 is sensitive to temperature changes and can rapidly expand when approaching the Curie temperature, causing the conductive fillers 3422 to be quickly separated, thereby cutting off the conductive channel. This sensitive and accurate temperature response characteristic helps to promptly detect and respond to temperature anomalies in the battery system, and immediately take insulation measures when the temperature just reaches or exceeds the Curie temperature, preventing the battery from overheating further, and thus effectively protecting the safety of the battery and the entire system.

[0049] The conductive fillers 3422 are uniformly dispersed in the thermally expandable polymer matrix 3421, so that the conductive and insulating properties of the functional layer 33 have good consistency and uniformity in each part. No matter which position of the tab body, when the temperature changes, the functional layer 33 can change its conductive-insulating state in the same way and speed, avoiding problems such as overheating or uneven conduction caused by local performance differences, and improving the stability and reliability of the overall performance of the battery connection tab.

[0050] In this preferred embodiment, parameters such as the Curie temperature, expansion coefficient, and conductive performance of the thermosensitive conductive polymer shell can be flexibly adjusted by selecting different thermally expandable polymer matrix materials, types of conductive fillers, and adjusting their ratios to adapt to different types of batteries, different working environments, and battery systems with different safety requirements. For example, for batteries operating in high-temperature environments, material combinations with higher Curie temperatures can be selected; for battery systems with strict weight requirements, thermally expandable polymer matrices and conductive fillers with lower densities can be used to reduce the weight of the tab while meeting the performance requirements.

[0051] As a preferred embodiment of the present invention, the polymer matrix 3421 is made of polyethylene, polypropylene, polyvinyl chloride or thermoplastic polyurethane.

[0052] Polyethylene (PE) has excellent flexibility, enabling the fabricated thermosensitive conductive polymer housing 342 to adapt to battery connection tabs of different shapes and sizes. During the assembly process of the battery module, it can withstand a certain degree of bending and stretching without breaking, ensuring the integrity and stability of the functional layer. Moreover, polyethylene also has excellent chemical stability, is resistant to acid and alkali corrosion, and is not easily eroded by chemical substances such as the electrolyte inside the battery, thereby extending the service life of the battery connection tab and ensuring that the performance of the thermosensitive conductive polymer housing does not change due to chemical effects during long-term use. At the same time, polyethylene is a common plastic with relatively low production costs and wide availability, which helps to reduce the overall cost of the battery connection tab and improve the market competitiveness of the product.

[0053] Polypropylene (PP) has high heat resistance and can maintain good physical properties at relatively high temperatures without being easily deformed. This enables the battery connection tab to still maintain its shape and structure under the heat generated during battery operation, ensuring the stable performance of the thermosensitive conductive polymer housing 342. Polypropylene also has good mechanical strength and relatively high tensile strength, and can withstand various external forces during the use of the battery module, such as vibration and extrusion, protecting the internal conductive filler 3422 and conductive channels from being damaged, thereby ensuring that the conductive performance and temperature response characteristics of the functional layer 33 are not affected. At the same time, polypropylene has a low density and is lightweight, which helps to reduce the overall weight of the battery module without affecting the performance of the battery connection tab, and is of great significance for some application scenarios with strict weight requirements, such as electric vehicles and drones.

[0054] Polyvinyl chloride (PVC) itself has excellent insulation properties, which provides additional insulation protection for the battery connection tab. Even when an abnormality occurs in the functional layer of the thermosensitive conductive polymer housing 342 for some reason, the PVC matrix can, to a certain extent, prevent the occurrence of leakage, improving the safety of the battery system. PVC has good processability and is easy to be made into products of different shapes and sizes through various molding processes, which can meet the diverse requirements of different battery modules for connection tabs. At the same time, its performance can be adjusted by adding different additives. For example, plasticizers can improve its flexibility, and flame retardants can enhance its fire resistance, further optimizing the comprehensive performance of the battery connection tab.

[0055] Thermoplastic polyurethane (TPU) has excellent elasticity and wear resistance, and can maintain good performance when the battery connection tab is subjected to repeated mechanical stress, such as the stress caused by the volume change during battery charging and discharging. TPU can still maintain good flexibility and elasticity at low temperatures. Its glass transition temperature is relatively low, generally between -30°C and -60°C, which enables the battery connection tab to work properly in cold environments without becoming brittle or losing function due to low temperature, thus broadening the operating temperature range of the battery system.

[0056] As a preferred embodiment of the present invention, the conductive filler 3422 is made of conductive metal nanoparticles, carbon nanotubes, carbon black particles or polythiophene.

[0057] Conductive metal nanoparticles such as silver, gold, copper, etc. have extremely high electrical conductivity, which can significantly improve the electrical conductivity of the functional layer. Below the Curie temperature, a small amount of metal nanoparticles can connect with each other to form an efficient conductive channel, greatly reducing the resistance of the battery connection tab, reducing the energy loss during current transmission, and improving the charge and discharge efficiency of the battery system. The nano-scale size makes the metal particles have a large specific surface area, which can fully contact with the thermally expandable polymer matrix 3421, increasing the interfacial area of interaction. Therefore, when the thermally expandable polymer matrix 3421 expands, it is easier to separate the conductive particles, improving the response sensitivity of the thermosensitive conductive polymer housing to temperature changes. And protected by the thermally expandable polymer matrix 3421, the conductive metal nanoparticles are not easily oxidized or corroded, and can maintain stable electrical conductivity during long-term use, ensuring the performance reliability and service life of the battery connection tab.

[0058] Carbon nanotubes have an extremely high aspect ratio, and the ratio of their length to diameter can reach several thousand or even higher, enabling them to form an efficient conductive network in the thermally expandable polymer matrix 3421, and achieving good electrical conductivity even at a relatively low filling amount. At the same time, carbon nanotubes have relatively high electrical conductivity, which can quickly conduct current, reduce the resistance of the battery connection tab, and improve the performance of the battery system. Moreover, carbon nanotubes have excellent mechanical properties, such as high strength and high modulus, which can enhance the mechanical properties of the polymer matrix. When the battery connection tab is subjected to external force, carbon nanotubes can play a role in strengthening and toughening, preventing cracks or damage in the functional layer, and improving the reliability and durability of the product.

[0059] Carbon black particles are a common industrial raw material with relatively low prices and wide sources. Using carbon black particles as conductive fillers can effectively reduce production costs and improve the market competitiveness of products while ensuring the performance of battery connection tabs. Carbon black particles have good dispersibility in the thermally expandable polymer matrix 3421 and can be evenly distributed within the thermally expandable polymer matrix 3421 to form a stable conductive network. This uniform distribution makes the conductive performance of the functional layer relatively consistent in each part, improving the performance stability and consistency of the product. By selecting carbon black particles with different particle sizes, structures, and surface properties, the conductive performance and temperature response characteristics of the thermosensitive conductive polymer housing 342 can be adjusted to meet the requirements of different battery systems. For example, carbon black particles with smaller particle sizes can improve the conductive performance and temperature response sensitivity, while carbon black particles with larger particle sizes can reduce costs to a certain extent and increase the stability of the material.

[0060] Polythiophene can be modified through methods such as chemical synthesis or physical doping to make it have good processability. Polythiophene is well mixed with the thermally expandable polymer matrix 3421 to form a uniform composite material, which is convenient for preparing the required shapes and sizes of battery connection tabs through various forming processes. Moreover, the conductivity of polythiophene can be adjusted by changing factors such as its molecular structure, dopant type, and concentration. This enables it to precisely adjust the conductive performance of the thermosensitive conductive polymer housing according to the requirements of different battery systems to achieve the best battery connection effect and temperature response characteristics. Additionally, polythiophene has certain thermal response characteristics. When the temperature rises above the Curie temperature, the movement of its molecular chains intensifies, the intermolecular interactions change, and the ordered structure that was originally beneficial for electron transport is destroyed, resulting in the obstruction of the electron transport path and thus a decrease in conductivity.

[0061] As a preferred embodiment of the present invention, referring to Figure 1 and Figure 6 as shown, at least one of the two side surfaces of the tab body in the thickness direction is connected with a phase change material plate 4, and the phase change material plate 4 can cover the intermediate body 3 in the thickness direction of the tab body.

[0062] Since the phase change material plate 4 is on the side surface of the tab body and can cover the intermediate body 3, when a short circuit or abnormal heating occurs in the battery system, the temperature of the tab body rises, and the phase change material in the phase change material plate 4 will absorb a large amount of heat and undergo a phase change, such as from a solid state to a liquid state. In this way, it can effectively take away the heat of the intermediate body 3 and the tab body, reduce the temperature of the tab body, and thus reduce the decline in battery performance and safety risks caused by high temperature. For example, at the moment of short circuit, the phase change material plate 4 quickly absorbs heat, preventing the intermediate body 3 from entering the insulating state too quickly due to overheating and affecting the stability of battery protection, and maintaining the normal operation of the battery system.

[0063] The presence of the phase change material plate 4 plays an auxiliary role in protecting the intermediate 3. During the process in which the thermosensitive conductive material responds to temperature changes and the intermediate 3 changes from a conductive state to an insulating state, the phase change material plate 4 can help control the rate of temperature change, avoid the adverse effects of sudden temperature changes on the performance of the thermosensitive conductive material, ensure that the intermediate 3 can stably switch between the conductive and insulating states, thereby enhancing the reliability of the battery connection tab to independently disconnect the circuit and protect the internal circuit of the battery module, and reducing the probability of safety accidents such as thermal runaway.

[0064] Preferably, the Curie temperature of the phase change material plate is lower than the Curie temperature of the thermosensitive conductive material.

[0065] During the operation of the battery system, when the temperature rises to the Curie temperature of the phase change material plate, the phase change material plate 4 first undergoes a phase change and reduces the temperature of the tab body and the surrounding environment by absorbing heat. For example, when the battery just starts to show slight overheating, the phase change material plate 4 can promptly activate the heat dissipation mechanism, avoid continuous heat accumulation, effectively reduce the temperature burden on the thermosensitive conductive material, and delay the time for it to reach the Curie temperature. During the phase change process of the phase change material plate 4, a relatively stable temperature range can be maintained within a certain period of time, creating a more stable working environment for other components in the battery module and reducing the impact of temperature fluctuations on the battery performance and lifespan. During the process in which the phase change material plate 4 continuously absorbs heat and maintains temperature stability, the charge and discharge efficiency of the battery can be maintained at a good level, thereby improving the overall performance of the battery system.

[0066] Since the Curie temperature of the phase change material plate is lower than the Curie temperature of the thermosensitive conductive material, that is, the phase change material plate 4 starts to dissipate heat at a lower temperature. If the temperature continues to rise, the thermosensitive conductive material will respond. This progressive protection mechanism enables the battery system to have corresponding protection measures in the face of different degrees of thermal anomalies. When the temperature only rises slightly, the phase change material plate 4 conducts preliminary cooling; only when the temperature seriously exceeds the standard, the thermosensitive conductive material disconnects the circuit, avoiding frequent disconnection of the circuit due to minor temperature fluctuations and ensuring the stability of the power supply of the battery system. By setting the phase change material plate 4 to intervene in heat dissipation in advance, the possibility of misjudgment of the thermosensitive conductive material is reduced. Because without the pre-heat dissipation of the phase change material plate, when the temperature rises rapidly, the thermosensitive conductive material may malfunction due to the temperature shock within a short period of time. The presence of the phase change material plate 4 stabilizes the rate of temperature change, ensures that the thermosensitive conductive material can accurately respond when the circuit really needs to be disconnected, and improves the reliability of the entire protection mechanism.

[0067] In the case where thermal runaway may occur in the battery system, the hierarchical protection of the phase change material plate 4 and the thermosensitive conductive material greatly enhances the safety of the system. The phase change material plate 4 suppresses the temperature rise in the early stage, buys time for the thermosensitive conductive material to play a role, prevents the further deterioration of thermal runaway, reduces the occurrence probability of serious safety accidents such as battery fire and explosion, and ensures the safe operation of electric vehicles and related equipment.

[0068] In one embodiment, the present invention also discloses a battery module. Refer to Figure 4 and Figure 5 as shown, which includes: A plurality of battery cells 5, the plurality of battery cells 5 are arranged side by side, and each of the battery cells 5 includes two pole columns 51 with opposite electrode polarities; The battery connection busbar according to any one of the above embodiments, the first conductor 1 and the second conductor 2 of the battery connection busbar are respectively electrically connected to the pole columns 51 of two adjacent battery cells 5.

[0069] In one embodiment, the present invention also discloses a battery pack, including the above battery module.

[0070] In one embodiment, the present invention also discloses an electrical device, including the above battery pack, and the battery pack is used to supply power to the electrical device.

[0071] The above embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention.

Claims

1. A battery connection tab, characterized in that: It includes a bar piece body, and the bar piece body includes a first conductor (1), an intermediate body (3), and a second conductor (2) that are sequentially connected along the length direction. The first conductor (1) and the second conductor (2) are respectively electrically connected to the pole columns (51) of two battery monomers (5); The intermediate body (3) is a thermosensitive conductive material. In response to the ambient temperature around the bar piece body being less than the Curie temperature of the thermosensitive conductive material, the intermediate body (3) is in a conductive state; in response to the ambient temperature around the bar piece body being greater than or equal to the Curie temperature of the thermosensitive conductive material, the intermediate body (3) is in an insulating state.

2. The battery connection tab according to claim 1, characterized in that: The intermediate body (3) includes a first encapsulation layer (31), a functional layer (33), and a second encapsulation layer (32) that are sequentially stacked along the thickness direction. The two ends of the functional layer (33) in the length direction are respectively in contact and cooperation with the first conductor (1) and the second conductor (2); The functional layer (33) is filled with thermosensitive conductive particles (34). The thermosensitive conductive particles (34) include conductive microparticles (341) and a thermosensitive conductive polymer shell (342) that wraps the surface of the conductive microparticles (341); in response to the ambient temperature around the bar piece body being less than the Curie temperature of the thermosensitive conductive polymer shell (342), the functional layer (33) is in a conductive state; in response to the ambient temperature around the bar piece body being greater than or equal to the Curie temperature of the thermosensitive conductive polymer shell (342), the functional layer (33) is in an insulating state.

3. The battery connection tab according to claim 2, wherein: The materials of the first encapsulation layer (31) and the second encapsulation layer (32) are polyimide, polyether ether ketone, or liquid crystal polymer; The material of the conductive microparticles (341) is conductive metal.

4. The battery connection tab according to claim 2, wherein: The thermosensitive conductive polymer shell (342) includes a thermally expandable polymer matrix (3421) and conductive fillers (3422) uniformly dispersed in the thermally expandable polymer matrix (3421); in response to the ambient temperature around the bar piece body being less than the Curie temperature of the thermosensitive conductive polymer shell (342), the conductive fillers (3422) are connected to each other to form a conductive channel, making the functional layer (33) in a conductive state; in response to the ambient temperature around the bar piece body being greater than or equal to the Curie temperature of the thermosensitive conductive polymer shell (342), the thermally expandable polymer matrix (3421) expands, and the conductive fillers (3422) are separated, cutting off the conductive channel, making the functional layer (33) in an insulating state.

5. The battery connection tab according to claim 4, characterized in that: The material of the polymer matrix (3421) is polyethylene, polypropylene, polyvinyl chloride, or thermoplastic polyurethane; The material of the conductive fillers (3422) is conductive metal nanoparticles, carbon nanotubes, carbon black particles, or polythiophene.

6. The battery connection tab according to claim 1, wherein: At least one of the two side surfaces of the bar piece body in the thickness direction is connected with a phase change material plate (4), and the phase change material plate (4) can cover the intermediate body (3) in the thickness direction of the bar piece body.

7. The battery connection tab according to claim 6, wherein: The Curie temperature of the phase change material plate (4) is less than the Curie temperature of the thermosensitive conductive material.

8. A battery module, characterized in that, It includes: A plurality of battery cells (5), the plurality of battery cells (5) are arranged side by side, and each battery cell (5) includes two pole posts (51) with opposite electrode polarities; The battery connection tab according to any one of claims 1 to 7, wherein the first conductor (1) and the second conductor (2) of the battery connection tab are respectively electrically connected to the pole posts (51) of two adjacent battery cells (5).

9. A battery pack, characterized in that: A battery module including the battery module according to claim 8.

10. An electrical device, characterized in that, A battery pack including the battery pack according to claim 9, the battery pack being used to supply power to the electrical device.

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