Integrated composite battery pole piece with integrated self-heating circuit

Abstract

The application provides an integrated composite battery pole piece with a self-heating circuit, wherein the battery pole piece is sequentially provided with a pole piece layer, an insulating support base material layer, an electric heating layer, a conductive circuit layer, a sealing isolation protection layer and the pole piece layer from bottom to top; the electric heating layer is arranged on the insulating support base material layer; the conductive circuit layer is symmetrically arranged on both sides of the electric heating layer and electrically connected with the electric heating layer; the sealing isolation protection layer is used for encapsulating the insulating support base material layer, the electric heating layer and the conductive circuit layer into an integral independent heating circuit; the conductive circuit layer is connected with a power supply; and the pole piece layer is arranged outside the sealing isolation protection layer and the insulating support base material layer and forms a reliable electrical isolation structure between the sealing isolation and the heating circuit. The application integrates the heating circuit and the battery pole piece, directly arranges a heat source in the pole piece, and maximally reduces the negative influence on the energy density of the battery under the premise of ensuring the heating effect.

Description

Technical Field

[0001] This invention relates to the field of power battery thermal management technology, and in particular to an integrated composite battery electrode with an integrated self-heating circuit. Background Technology

[0002] With the rapid development of the new energy industry, the environmental adaptability, charge / discharge efficiency, and lifespan of power batteries, as core energy storage components, have become key bottlenecks in the industry's development. Lithium-ion batteries experience significant performance degradation at low temperatures, specifically manifested as increased SEI film impedance on the negative electrode surface, decreased electrolyte ionic conductivity, and a slower lithium intercalation reaction kinetic rate in the active materials. This leads to a sharp reduction in battery discharge capacity, a significant increase in DC internal resistance, and a significant decrease in charging efficiency. Test data shows that at -7℃, the driving range of new energy vehicles is reduced by an average of 41% compared to 24℃; and in extremely cold environments of -30℃ and below, batteries may even fail to start normally or complete charging. These problems severely restrict the widespread adoption of downstream applications such as new energy vehicles and energy storage power stations that rely on power batteries.

[0003] The current mainstream technology in the industry involves installing heating devices inside the battery pack or outside the cells to achieve low-temperature heating through indirect heat transfer to the cell casing. However, this traditional heating method has three inherent drawbacks: First, it has low heat conduction efficiency, as heat must first pass through the air gap between the heating device and the cell casing before being conducted to the inside of the cell, resulting in significant heat loss. Second, it suffers from poor heating uniformity, with the temperature rising rapidly in areas near the heating device, while heat conduction is slow in the central area and areas far from the heating device, easily leading to large local temperature differences and exacerbating local stress attenuation within the cell. Third, the heating device occupies additional internal space in the battery pack, reducing the overall energy density of the battery pack.

[0004] Recently, a few built-in heating technologies have emerged in the industry, such as setting a heating element separately inside the battery cell or integrating a heating layer on the outside of the electrode. However, these solutions still have significant technical shortcomings: First, the heating layer in these solutions can only heat the electrode on one side, failing to cover the entire active area of ​​the electrode, resulting in uneven heating. Second, the insulation isolation between the heating circuit and the electrode charging and discharging circuit in these solutions is not perfect, making it prone to safety risks such as insulation layer damage and short circuits during long-term charge-discharge cycles of the battery cell or during long-term thermal cycles of the heating circuit. In addition, the integration of the heating device and the electrode in these solutions is low, requiring additional fixing structures, which not only further occupies valuable space inside the battery cell but also increases the complexity of the battery cell manufacturing process.

[0005] Therefore, developing a built-in heated composite electrode that is compatible with existing winding / stacking processes, has high heating efficiency, good heating uniformity, high safety and reliability, and minimal impact on cell energy density has become a technological necessity in the field of power battery thermal management. Summary of the Invention

[0006] This invention provides an integrated composite battery electrode with an integrated self-heating circuit to solve one or more technical problems encountered in the prior art.

[0007] In a first aspect, embodiments of the present invention provide an integrated composite battery electrode with an integrated self-heating circuit, suitable for liquid, semi-solid, and all-solid-state battery systems. From bottom to top, it comprises an electrode layer, an insulating support substrate layer, an electrothermal layer, a conductive circuit layer, a sealing and isolation protective layer, and the electrode layer itself. The electrothermal layer is disposed on the insulating support substrate layer. The conductive circuit layers are symmetrically disposed on both sides of the electrothermal layer and electrically connected to it. The sealing and isolation protective layer encapsulates the insulating support substrate layer, the electrothermal layer, and the conductive circuit layer into an integrated independent heating circuit. The conductive circuit layer is connected to a power source. The electrode layer is disposed outside the sealing and isolation protective layer and the insulating support substrate layer, forming a reliable electrical isolation structure between it and the heating circuit through sealing and isolation.

[0008] In a preferred embodiment, the electric heating layer is a full-surface heating structure, the outline of which is adapted to the outline of the electrode layer to achieve synchronous and uniform heat release across the entire electrode area; or, the electric heating layer is an S-shaped bending structure, the bending spacing and number of which are adjusted to meet the thermal management requirements of different electrodes.

[0009] In a preferred embodiment, the conductive circuit layer consists of symmetrically arranged positive and negative conductive circuits; the positive and negative conductive circuits extend along the length of the electrode layer, and their relative distance remains consistent throughout the entire length; the leads of the positive and negative conductive circuits are each connected to an independent heating electrode tab; the heating electrode tab and the charging / discharging electrode tab of the electrode layer are spatially staggered, and an insulating separator is provided between them.

[0010] In a preferred embodiment, the edge region of the sealing and protective layer extends at least 1 mm beyond the edge regions of the electrothermal layer and the conductive circuit layer.

[0011] In a preferred embodiment, the electrode layer is disposed on the outer surface of the sealing and protective layer and the insulating support substrate layer, and the inner surface of the electrode layer forms a tightly fitted insulating structure with the outer surface of the sealing and protective layer and the insulating support substrate layer.

[0012] In a preferred embodiment, the conductive circuit layer is connected to an independent heating tab, and the heating tab and the charge / discharge tab of the electrode layer are spatially misaligned.

[0013] In a preferred embodiment, the electrothermal layer is a semiconductor electrothermal thin film layer composed of a main phase metal oxide matrix, a doped modified component, and an oxygen vacancy defect regulating component. The metal oxide matrix is ​​at least one of the following metal oxide semiconductor materials: fluorine-doped tin dioxide, antimony-doped tin dioxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, vanadium pentoxide, indium zinc oxide, molybdenum-doped indium oxide, and indium tin oxide; or one or more of the following conductive polymers: graphene, carbon nanotubes, metal alloys, or conductive polymers, prepared by physical vapor deposition, printing, or coating processes. The insulating support substrate layer and the sealing and protective layer are made of at least one of the following materials: electrolyte-resistant and high / low temperature resistant polyester polymer film, polyimide polymer film, or special high-temperature resistant engineering polymer film. The total thickness of the insulating support substrate layer and the sealing and protective layer does not exceed 1 mm.

[0014] In a preferred embodiment, when the composite battery electrode is adapted to a liquid battery, a conventional porous membrane structure is provided on the outer side of its electrode layer; when adapted to a semi-solid battery, a polymer-inorganic composite solid electrolyte layer is provided on the outer side of its electrode layer; and when adapted to an all-solid battery, a polymer, oxide, or sulfide solid electrolyte layer is provided on the outer side of its electrode layer.

[0015] In a preferred embodiment, the electrode layer is a positive electrode or a negative electrode, wherein the active material layer of the positive electrode is at least one of layered oxide, spinel oxide, olivine phosphate and lithium-rich manganese-based, and the active material layer of the negative electrode is at least one of carbon-based, silicon-based, titanium-based and alloy-based.

[0016] In a preferred embodiment, the composite battery electrode, separator, and paired electrode are stacked in sequence and then a fixed structure is formed by thermal bonding process, which is suitable for manufacturing battery cells using winding or stacking processes.

[0017] One of the above technical solutions has the following advantages or beneficial effects: (1) High heating efficiency: This invention integrates the electric heating layer directly inside the composite battery electrode. The entire electric heating layer is completely wrapped by the electrode layer. The heat generated during operation is directly transferred to the active material layer of the electrode through thermal conduction, and then further transferred to the inside of the battery cell. This eliminates the additional air layer thermal resistance and shell conduction thermal resistance in traditional external heating schemes, and greatly improves the thermal conduction efficiency. Actual test data shows that in an environment of -30℃, the battery cell using the composite electrode of this invention can achieve a heating rate of more than 5℃ / min, and the time required to heat to 0℃ is only 1 / 5 to 1 / 10 of that of the traditional external heating scheme; and the energy consumption during the heating process accounts for less than 5% of the battery's own energy.

[0018] (2) Good heating uniformity: The electric heating layer of the present invention adopts a full-surface heating structure, and its contour shape is perfectly matched with the contour shape of the electrode layer, which can uniformly heat the entire active area of ​​the electrode. At the same time, the electric heating layer is located in the middle of the electrode layer, and the heat can be conducted to the electrode layers on both sides simultaneously, effectively reducing the local temperature difference on the electrode surface. Even in areas with large differences in heat transfer characteristics, such as the arc area and the straight area of ​​the wound cell, the full-surface heating characteristic of the electric heating layer can compensate for the differences in heat transfer resistance in different areas. Actual test data show that the maximum local temperature difference on the electrode surface of the cell using the composite electrode of the present invention is ≤5℃ during the heating process, which is much lower than the 10℃~15℃ of the traditional external heating scheme, effectively avoiding local overheating or overcooling, and is conducive to improving the cycle life of the battery.

[0019] (3) High safety and reliability: This invention uses a double-layer insulation structure consisting of an insulating support substrate layer and a sealed isolation protective layer to completely isolate the heating layer, conductive circuit layer, and electrode layer. The edge of the sealed isolation protective layer extends at least 1 mm beyond the edge of the heating layer, forming a reliable insulation barrier. Simultaneously, the heating tabs and charging / discharging tabs are spatially staggered, avoiding the risk of electrical short circuits between the tabs. Furthermore, the use of an insulating material with good compatibility with the electrolyte effectively prevents corrosion and insulation layer damage in the heating circuit during long-term use. Experimental data shows that after more than 1000 thermal cycle tests, the composite electrode of this invention still meets battery safety standards, with a near-zero risk of short circuits.

[0020] (4) High integration and low energy density loss: The present invention designs the heating circuit and the electrode layer as an integrated composite structure. The electric heating layer and the conductive line layer are completely encapsulated between the insulating support substrate layer and the sealing isolation protection layer, without occupying additional radial space inside the cell. At the same time, by optimizing the thickness parameters of each layer, the total thickness of the insulating support substrate layer and the sealing isolation protection layer is controlled within 1 mm, and the thickness of the electric heating layer is controlled within 50 μm. The negative impact on the energy density of the cell is controlled within 5%, which is far lower than the 10% to 15% of the traditional built-in heating scheme. Under the premise of ensuring the heating effect, the battery energy density and low temperature heating performance are taken into account to the maximum extent.

[0021] (5) Strong process adaptability: The composite electrode of the present invention can be combined with the separator and the paired electrode to be prefabricated into a fixed structure by the thermal composite process, and then directly adapted to the winding or stacking process to manufacture the cell. There is no need to make large-scale modifications to the existing power battery mass production process line. Only the corresponding deposition or coating process needs to be added in the electrode manufacturing process to complete the mass production upgrade. At the same time, by adjusting the material, power density and contour size of the electric heating layer, it can be flexibly adapted to power batteries with different chemical systems (liquid, semi-solid, all-solid) and different shapes and specifications, and has extremely strong process compatibility and mass production feasibility.

[0022] (6) Significantly Improved Low-Temperature Performance: The built-in electrothermal layer of this invention can raise the temperature of the electrode itself to the optimal operating range in a very short time, directly accelerating the electrochemical reaction rate between the active material of the electrode and the electrolyte, and significantly improving the discharge performance of the battery in low-temperature environments. Actual test data show that in an environment of -30℃, the discharge capacity retention rate of the battery cell using the composite electrode of this invention is more than 30% higher than that of the battery cell using the traditional external heating solution; at 50% state of charge (SOC), the discharge power density is 5 to 6 times that of ordinary battery cells; in an extremely cold environment of -40℃, the battery cell temperature can still be raised to 0℃ within 45s, meeting the normal charging and discharging requirements.

[0023] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0024] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in the invention and should not be construed as limiting the scope of the invention.

[0025] Figure 1This is a schematic diagram of the overall structure of the integrated composite battery electrode with a self-heating circuit integrated in this embodiment. Detailed Implementation

[0026] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0027] This invention provides an integrated composite battery electrode with an integrated self-heating circuit, see [link / reference]. Figure 1 As shown, the integrated composite battery electrode sheet comprises, from bottom to top, an electrode layer 100, an insulating support substrate layer 200, an electric heating layer 300, a conductive circuit layer 400, a sealing and isolation protective layer 500, and an electrode layer 100. The electric heating layer 300 is disposed on the insulating support substrate layer 200. The conductive circuit layer 400 is disposed on both sides of the electric heating layer 300 and electrically connected to the electric heating layer 300. The sealing and isolation protective layer 500 is used to encapsulate the insulating support substrate layer 200, the electric heating layer 300, and the conductive circuit layer 400 into an integrated independent heating circuit. The conductive circuit layer 400 is connected to a power source. The electrode layer 100 is disposed outside the sealing and isolation protective layer 500 and the insulating support substrate layer 200 and electrically isolated from the heating circuit through sealing and isolation.

[0028] This embodiment integrates the heating circuit with the battery electrode into a composite design, placing the heat source directly inside the electrode. This minimizes the negative impact on the battery's energy density while ensuring heating performance.

[0029] As a preferred embodiment, the electric heating layer 300 is a full-surface heating structure, and its outline shape is adapted to the outline shape of the electrode layer 100.

[0030] As a preferred embodiment, the conductive circuit layer 400 is composed of symmetrically arranged positive conductive circuits and negative conductive circuits, which respectively form a complete electrical connection loop with the two sides of the electric heating layer 300.

[0031] As a preferred embodiment, the edge region of the sealing and protective layer 500 extends at least 1 mm beyond the edge regions of the electric heating layer 300 and the conductive circuit layer 400.

[0032] As a preferred option, see Figure 1 As shown, the electrode layer 100 covers the outer surfaces of the sealing and protective layer 500 and the insulating support substrate layer 200, and a tightly fitted insulating and protective structure is formed between the inner surface of the electrode layer 100 and the outer surface of the sealing and protective layer 500.

[0033] As a preferred embodiment, the conductive line layer 400 is connected to an independent heating tab, and the heating tab is spatially offset from the charging and discharging tab of the electrode layer 100.

[0034] As a preferred embodiment, the material of the electric heating layer 300 is at least one of nickel, indium tin oxide, graphene, and carbon nanotubes; the material of the insulating support substrate layer 200 is at least one of polypropylene, polyethylene, and polyimide; and the material of the sealing and protective layer 500 is at least one of thermally conductive silicone and thermally conductive polyimide.

[0035] As a preferred embodiment, the total thickness of the insulating support substrate layer 200 and the sealing and protective layer 500 does not exceed 1 mm.

[0036] In a preferred embodiment, when the composite battery electrode is adapted to a liquid battery, a conventional porous membrane structure is provided on the outer side of its electrode layer 100; when adapted to a semi-solid battery, a polymer-inorganic composite solid electrolyte layer is provided on the outer side of its electrode layer 100; and when adapted to an all-solid battery, a polymer, oxide, or sulfide solid electrolyte layer is provided on the outer side of its electrode layer 100.

[0037] As a preferred embodiment, the electrode layer 100 is a positive electrode or a negative electrode, wherein the active material layer of the positive electrode is at least one of layered oxide, spinel oxide, olivine phosphate and lithium-rich manganese-based, and the active material layer of the negative electrode is at least one of carbon-based, silicon-based, titanium-based and alloy-based.

[0038] As a preferred embodiment, the composite battery electrode, separator, and paired electrode are stacked in sequence and then a fixed structure is formed by thermal composite process, which is suitable for manufacturing battery cells using winding or stacking processes.

[0039] As a preferred embodiment, the power density of the electric heating layer 300 is 0.05 to 1 W / cm²; the thickness of the electric heating layer 300 is 15 μm to 50 μm; the thickness of the insulating support substrate layer 200 is 0.5 μm to 1 μm; and the thickness of one side of the sealing and protective layer 500 is 0.4 μm to 0.5 μm.

[0040] As a preferred embodiment, the insulating support substrate layer 200 and the sealing and protective layer 500 are composite structures, with the base material being at least one of polyimide and polypropylene, and the surface material being thermally conductive silicone; the preparation process of the insulating support substrate layer 200 and the sealing and protective layer 400 is at least one of injection molding, compression molding, and coating processes.

[0041] As a preferred embodiment, the conductive circuit layer 400 is made of at least one of copper, aluminum, and copper-nickel plating; the conductive circuit layer 400 is prepared by at least one of physical vapor deposition, printing, and coating processes.

[0042] As a preferred embodiment, the distance between the heating tab and the charge / discharge tab is not less than 5 mm; the lead-out direction of the heating tab is completely opposite to the lead-out direction of the charge / discharge tab; the heating tab and the charge / discharge tab are electrically isolated from the battery cell casing by an insulating isolator.

[0043] As a preferred embodiment, the electric heating layer 300 has an S-shaped bending structure or a planar structure that continuously covers the entire surface; the resistance of the electric heating layer 300 is 8mΩ to 10mΩ.

[0044] Example 1 This embodiment provides an integrated composite battery electrode with an integrated self-heating circuit. See also... Figure 1 As shown, the integrated composite battery electrode sheet comprises, from bottom to top, an electrode layer 100, an insulating support substrate layer 200, an electric heating layer 300, a conductive circuit layer 400, a sealing and isolation protective layer 500, and an electrode layer 100. The electric heating layer 300 is disposed on the insulating support substrate layer 200. The conductive circuit layer 400 is disposed on both sides of the electric heating layer 300 and electrically connected to the electric heating layer 300. The sealing and isolation protective layer 500 is used to encapsulate the insulating support substrate layer 200, the electric heating layer 300, and the conductive circuit layer 400 into an integrated independent heating circuit. The conductive circuit layer 400 is connected to a power source. The electrode layer 100 is disposed outside the sealing and isolation protective layer 500 and the insulating support substrate layer 200 and electrically isolated from the heating circuit through sealing and isolation.

[0045] Specifically, the electric heating layer 300 is a planar heating structure that continuously covers the entire surface. Its outline shape is perfectly matched with the outline size of the electrode layer 100, which can uniformly heat the entire active area of ​​the electrode layer 100. The electric heating layer 300 is made of indium tin oxide, and its thickness is controlled within the range of 30nm. It is uniformly prepared on the upper surface of the insulating support substrate layer 200 by physical vapor deposition (PVD).

[0046] Specifically, the conductive circuit layer 400 consists of a positive conductive circuit and a negative conductive circuit, which are respectively arranged on the left and right edges of the electric heating layer 300 and extend along the length of the electrode sheet; the conductive circuit layer 400 is made of copper plated with nickel, and is prepared and formed simultaneously with the electric heating layer through PVD process, and its thickness is consistent with that of the electric heating layer 300.

[0047] Specifically, both the insulating support substrate layer 200 and the sealing and isolation protective layer 500 are made of high-temperature resistant polypropylene and are prepared by molding process. The thickness of the insulating support substrate layer 200 is controlled within the range of 0.8 mm, and the thickness of one side of the sealing and isolation protective layer 500 is controlled within the range of 0.4 mm. The left and right edge areas of the sealing and isolation protective layer 500 extend 1.5 mm beyond the edge areas of the electric heating layer 300 and the conductive line layer 400, respectively, forming a reliable side insulation barrier.

[0048] Specifically, the electrode layer 100 includes a positive electrode layer and a negative electrode layer, which are respectively disposed on the upper surface of the sealing and protective layer 500 and the lower surface of the insulating support substrate layer 200; the active material of the positive electrode layer is lithium iron phosphate, and the active material of the negative electrode layer is artificial graphite; the electrode layer 100 is bonded and fixed to the sealing and protective layer 500 and the insulating support substrate layer 200 into an integrated structure by means of insulating and thermally conductive adhesive.

[0049] Specifically, the positive and negative conductive lines of the conductive line layer 400 are each led out with independent heating tabs from the same edge of the electrode sheet; the material of the heating tabs is consistent with that of the conductive line layer 400, and they are welded and fixed to the lead-out end of the conductive line layer 400 by ultrasonic welding process; the heating tabs and the charge / discharge electrodes of the electrode sheet layer 100 are completely staggered in space by being led out from opposite sides, and the straight-line distance between them is controlled to be more than 5mm to avoid the risk of electrical short circuit between the electrodes; the heating tabs and the charge / discharge electrodes are completely electrically isolated from the subsequently assembled cell housing by matching insulating isolation components.

[0050] Example 2 The only difference between this embodiment and Embodiment 1 is the material and manufacturing process of the electric heating layer 300: See Figure 1 As shown, in this embodiment, the electric heating layer 300 is a graphene conductive heating film, uniformly prepared on the upper surface of the insulating support substrate layer by screen printing. The thickness of the electric heating layer 300 is controlled within 20 nm, and the heating power density is controlled within 0.8 W / cm². The insulating support substrate layer 200 and the sealing and protective layer 500 are made of polyimide and are prepared by coating. The edge region of the sealing and protective layer 500 extends 2 mm beyond the edge region of the electric heating layer 300. The remaining structures and preparation processes of this embodiment are consistent with those of Embodiment 1.

[0051] Example 3 The only difference between this embodiment and Embodiment 1 is the structure of the electric heating layer 300: the electric heating layer 300 in this embodiment has an S-shaped bending structure. This structure allows for flexible adjustment of the total resistance of the electric heating layer within a limited electrode space by adjusting the spacing and number of bends, stabilizing its resistance within the range of 8mΩ to 10mΩ. The electric heating layer 300 is made of nickel and is fabricated using a PVD process. The thickness of the insulating support substrate layer 200 is controlled within 1mm, and the thickness of the sealing and protective layer 500 on one side is controlled within 0.5mm. The remaining structures and fabrication processes of this embodiment are consistent with those of Embodiment 1.

[0052] Example 4 This embodiment provides a method for preparing the integrated composite battery electrode with an integrated self-heating circuit as described in Embodiment 1. See [link to previous embodiment]. Figure 1 As shown, it includes the following steps: Step 1: Preparation of insulating support substrate layer 200: High-temperature resistant polypropylene raw material is processed into sheet insulating substrate using molding process, and the substrate sheet is cut into appropriate size according to the target electrode size. The upper surface of the substrate sheet is corona treated to improve its surface adhesion strength. Step 2: Preparation of the electric heating layer 300: Using PVD process, a 30nm thick indium tin oxide heating film is uniformly deposited on the corona-treated upper surface of the insulating support substrate layer 200. The conductive circuit layer 400 is reserved on the left and right sides of the heating film by a precision mask. Step 3: Fabrication of conductive circuit layer 400: Using PVD process, copper-plated nickel conductive circuits with the same thickness as the electric heating layer 300 are simultaneously deposited in reserved areas on both sides of the electric heating layer 300. The edges of the circuits are trimmed by laser precision cutting process to ensure that the accuracy of the circuit width and spacing meets the design requirements. Step 4: Encapsulating the heating circuit: The surrounding areas of the prepared electric heating layer 300 and conductive circuit layer 400 are filled and sealed with matching insulating strips; then, high-temperature resistant polypropylene raw material preheated to 120°C in a molten state is uniformly coated on the upper surface of the electric heating layer 300 and conductive circuit layer 400, and sealed and bonded to the edge area of ​​the insulating support substrate layer 200 through a hot pressing process to form a sealed and protective layer 500, which completely encapsulates the electric heating layer 300 and conductive circuit layer 400. Step 5: Preparation of electrode layer 100: The positive electrode active material slurry is uniformly coated on one side of the aluminum current collector, and the negative electrode active material slurry is uniformly coated on one side of the copper current collector. After drying, rolling and cutting, the positive electrode layer and the negative electrode layer are formed respectively. Step Six: Composite Molding: A uniformly thick layer of insulating and thermally conductive adhesive is applied to the upper surface of the sealing and protective layer 500 and the lower surface of the insulating support substrate layer 200. Subsequently, the positive electrode layer and the negative electrode layer are precisely bonded to the corresponding adhesive layer. The layers are then bonded and fixed into a whole through a thermal bonding process to obtain an integrated composite battery electrode. The temperature of the thermal bonding process is controlled within the range of 100℃ to 120℃, and the pressure is controlled within the range of 0.2MPa to 0.5MPa to ensure tight bonding between the layers. Step 7: Electrode welding: The heating electrode tabs are welded and fixed to the lead-out end of the conductive circuit layer 400 using ultrasonic welding process, and the charge / discharge electrode tabs are welded and fixed to the current collector of the electrode layer; the welding position of the electrode tabs is wrapped with insulating materials to complete the preparation of the composite electrode.

[0053] Example 5 This embodiment provides a heating control system for a battery cell. The control system includes the composite battery electrode sheet described in Embodiment 1, a BMS main control unit, a power drive module, a temperature acquisition module, and a temperature sensor. The BMS main control unit is electrically connected to the heating tab of the composite electrode sheet through the power drive module. The temperature acquisition module is electrically connected to the BMS main control unit and also electrically connected to the temperature sensor disposed inside the battery cell. The detection end of the temperature sensor is directly attached to the surface of the positive electrode layer of the composite electrode sheet to collect temperature data of the electrode surface in real time.

[0054] Specifically, the BMS main control unit has a built-in multi-battery system adaptation algorithm, which can automatically match the corresponding heating parameters according to the thermal characteristics of different battery systems. The BMS main control unit also has an interlock control function. When it is detected that the charging and discharging current of the battery cell exceeds the preset safe current threshold, or the internal temperature of the battery cell exceeds the preset safe upper temperature threshold, or an insulation fault occurs in the heating circuit, the output of the power drive module will be automatically cut off, and the heating of the electric heating layer will be stopped to ensure the safety of the battery cell.

[0055] Specifically, the control system has three operating modes that can be automatically switched according to different actual scenarios: (1) Low temperature static preheating mode: When the vehicle is stationary and the ambient temperature is lower than the low temperature start-up threshold of the battery system, the BMS main control unit controls the power drive module to deliver rated power to the electric heating layer and quickly raise the internal temperature of the cell to the optimal working range. (2) Driving constant temperature maintenance mode: When the vehicle is in driving state and the battery cell is in charging and discharging state, the BMS main control unit dynamically adjusts the input power of the electric heating layer according to the real-time temperature data fed back by the temperature acquisition module, so as to accurately maintain the internal temperature of the battery cell within the optimal working range of 25℃~35℃. (3) Preheating mode before charging: When the vehicle is connected to the charging equipment, the BMS main control unit detects that the internal temperature of the battery cell is lower than the low temperature charging threshold. It first starts the electric heating layer for preheating. After the internal temperature of the battery cell reaches the safe charging range, the charging process is started.

[0056] Example 6 To verify the technical effect of the present invention, a performance comparison test was conducted on the soft-pack battery cell using the composite electrode sheets described in Examples 1-3 and the same soft-pack battery cell using a traditional external heating scheme (comparative example) under extremely cold conditions. The test conditions were in accordance with GB / T31486-2015 "Electrical Performance Requirements and Test Methods for Power Batteries for Electric Vehicles". The test results are as follows: Electric heating layer material Indium Tin Oxide graphene nickel External heating film heating rate 5.2℃ / min 5.5℃ / min 5.8℃ / min 0.5℃ / min Time required to heat to 0℃ 48s 45s 42s 720s Maximum temperature difference on electrode surface 3.2℃ 2.9℃ 2.5℃ 12.3℃ heating energy consumption ratio 4.2% 4.5% 4.8% 15.2% Table 1 Comparison of heating performance under different heating schemes (ambient temperature -40℃) Discharge capacity retention 82.3% 83.5% 84.2% 52.7% Discharge voltage plateau 3.22V 3.25V 3.28V 2.85V Discharge power density at 50% SOC 1025W / kg 1080W / kg 1120W / kg 210W / kg Table 2 Comparison of low-temperature discharge performance under different heating schemes (ambient temperature -40℃, 0.3C discharge) Capacity retention after 1000 cycles 95.2% 95.8% 96.1% 89.5% Insulation resistance after heating 1000 times 1200MΩ 1250MΩ 1300MΩ No heating circuit Energy density loss rate 3.2% 3.5% 3.8% 12.5% Table 3 Comparison of cycle performance under different heating schemes (ambient temperature 25℃, 1C charge / discharge) As can be seen from the above test data, the integrated composite electrode solution of the present invention is significantly superior to the traditional external heating solution in terms of core indicators such as heating efficiency, heating uniformity, low-temperature discharge performance, and cycle stability. Moreover, the electric heating layers of different materials and structures can stably achieve rapid internal heating of the cell while controlling the energy density loss rate to within 5%, which fully meets the actual usage requirements of vehicle power batteries and energy storage batteries.

[0057] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0058] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0060] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An integrated composite battery electrode with an integrated self-heating circuit, suitable for liquid, semi-solid, and all-solid-state battery systems, characterized in that, From bottom to top, the device comprises an electrode layer, an insulating support substrate layer, an electric heating layer, a conductive circuit layer, a sealing and isolation protective layer, and an electrode layer. The electric heating layer is disposed on the insulating support substrate layer. The conductive circuit layers are symmetrically disposed on both sides of the electric heating layer and electrically connected to it. The sealing and isolation protective layer is used to encapsulate the insulating support substrate layer, the electric heating layer, and the conductive circuit layer into an integrated independent heating circuit. The conductive circuit layer is connected to a power source. The electrode layer is disposed outside the sealing and isolation protective layer and the insulating support substrate layer, forming a reliable electrical isolation structure between it and the heating circuit through sealing and isolation.

2. The integrated composite battery electrode with integrated self-heating circuit according to claim 1, characterized in that, The electric heating layer is a full-surface heating structure, and its outline shape is adapted to the outline shape of the electrode layer to achieve synchronous and uniform heat release across the entire electrode area; or, the electric heating layer is an S-shaped bending structure, and the bending spacing and number are adjusted to meet the thermal management requirements of different electrodes.

3. The integrated composite battery electrode with an integrated self-heating circuit according to claim 1, characterized in that, The conductive circuit layer consists of symmetrically arranged positive and negative conductive circuits; the positive and negative conductive circuits extend along the length of the electrode layer, and their relative distance remains consistent throughout the entire length; the leads of the positive and negative conductive circuits are each connected to an independent heating electrode tab; the heating electrode tab and the charging / discharging electrode tab of the electrode layer are spatially staggered, and an insulating separator is provided between them.

4. The integrated composite battery electrode with an integrated self-heating circuit according to claim 1, characterized in that, The edge region of the sealed isolation protective layer extends at least 1 mm beyond the edge regions of the electric heating layer and the conductive circuit layer.

5. The integrated composite battery electrode with an integrated self-heating circuit according to claim 1, characterized in that, The electrode layer is disposed on the outer surface of the sealing and protective layer and the insulating support substrate layer, and the inner surface of the electrode layer forms a tightly fitted insulating structure with the outer surface of the sealing and protective layer and the insulating support substrate layer.

6. The integrated composite battery electrode with an integrated self-heating circuit according to claim 1, characterized in that, The conductive circuit layer is connected to an independent heating tab, and the heating tab and the charging / discharging tab of the electrode layer are spatially misaligned.

7. The integrated composite battery electrode with an integrated self-heating circuit according to claim 1, characterized in that, The electrothermal layer is a semiconductor electrothermal thin film layer composed of a main phase metal oxide matrix, doped modified components, and oxygen vacancy defect regulating components. The metal oxide matrix is ​​at least one of the following metal oxide semiconductor materials: fluorine-doped tin dioxide, antimony-doped tin dioxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, vanadium pentoxide, indium zinc oxide, molybdenum-doped indium oxide, and indium tin oxide; or one or more of the following conductive polymers: graphene, carbon nanotubes, metal alloys, or conductive polymers, prepared by physical vapor deposition, printing, or coating processes. The insulating support substrate layer and the sealing and isolation protective layer are made of at least one of the following materials: electrolyte-resistant and high / low temperature resistant polyester polymer film, polyimide polymer film, or special high-temperature resistant engineering polymer film. The total thickness of the insulating support substrate layer and the sealing and isolation protective layer does not exceed 1 mm.

8. The integrated composite battery electrode with an integrated self-heating circuit according to claim 1, characterized in that, When the composite battery electrode is adapted to a liquid battery, a conventional porous membrane structure is provided on the outer side of its electrode layer; when adapted to a semi-solid battery, a polymer-inorganic composite solid electrolyte layer is provided on the outer side of its electrode layer; when adapted to an all-solid battery, a polymer, oxide, or sulfide solid electrolyte layer is provided on the outer side of its electrode layer.

9. The integrated composite battery electrode with an integrated self-heating circuit according to claim 1, characterized in that, The electrode layer is a positive electrode or a negative electrode, wherein the active material layer of the positive electrode is at least one of layered oxide, spinel oxide, olivine phosphate and lithium-rich manganese-based, and the active material layer of the negative electrode is at least one of carbon-based, silicon-based, titanium-based and alloy-based.

10. The integrated composite battery electrode with an integrated self-heating circuit according to any one of claims 1-9, characterized in that, The composite battery electrode, separator, and paired electrode are stacked in sequence and then a fixed structure is formed by thermal composite process, which is suitable for winding or stacking process to manufacture battery cells.

Images