Battery thermal management structure based on heat pipe and phase change material and manufacturing method thereof

Abstract

The application discloses a battery thermal management structure based on a heat pipe and a phase change material and a manufacturing method thereof. The structure comprises a battery box, a plurality of batteries, a heat pipe, a phase change material and a cooling liquid flow channel. The battery box adopts an integrated design and additive manufacturing, and is internally integrated with a flat plate heat pipe, a phase change material and a baffle type cooling liquid flow channel. A plurality of L-shaped or U-shaped designed flat plate heat pipes are arranged between the batteries, and directly exchange heat with the batteries and the cooling liquid flow channel. The phase change material is filled between the flat plate heat pipes, directly contacts the flat plate heat pipe wall surface, and contacts the batteries through the plate structure of the battery box end plate and the partition plate. Through the coupling of the flat plate heat pipe and the phase change material, the baffle cooling liquid flow channel is arranged in a staggered mode, efficient heat dissipation and low temperature heating of the batteries are realized, and the batteries work in an optimal temperature range. The structure has high integration, good heat dissipation effect and is suitable for batch manufacturing, and ensures that the batteries can maintain the optimal working temperature under different environments and working conditions.

Description

Technical Field

[0001] This invention belongs to the field of battery thermal management and relates to a battery thermal management structure, particularly a battery thermal management structure based on heat pipes and phase change materials and its manufacturing method. It can effectively reduce the number of parts, simplify the assembly process, reduce thermal resistance, lower the maximum battery temperature, improve battery temperature uniformity, and realize the integrated design of load-bearing and thermal control structure and function. Background Technology

[0002] Battery thermal management technology is used to control the temperature and heat flow of a battery to improve its performance, safety, and lifespan. To enhance battery safety and extend its lifespan, thermal management technology is particularly important. Batteries generate a significant amount of heat during high-rate charging and discharging. If this heat is not dissipated in time, the battery temperature will rise excessively, exceeding its normal operating temperature (25℃-45℃). Overheating accelerates irreversible reactions in battery materials, reduces battery capacity, and shortens lifespan. Conversely, if lithium batteries are used in low-temperature environments, the increased electrolyte viscosity and decreased ion conductivity result in poor performance during both charging and discharging. Battery power and capacity will significantly decrease, and in severe cases, lithium ions may precipitate due to excessive concentration, forming lithium dendrites that could puncture the separator, leading to internal short circuits, reduced capacity, and shortened cycle life. Therefore, maintaining the battery within its normal operating temperature range can reduce the risk of thermal runaway and the rate of battery aging, thus extending battery lifespan.

[0003] Currently, common technologies used in battery thermal management systems include air cooling, liquid cooling, phase change material (PCM) cooling, and heat pipe cooling. Each technology has its advantages and disadvantages, requiring selection and optimization based on different application scenarios and needs. Heat pipe cooling utilizes heat pipes as heat exchange carriers, controlling battery temperature through heat conduction via the phase change of the working medium. During the evaporation phase, the PCM absorbs heat generated by the battery and then transfers it to the external environment through the condensation section, achieving rapid cooling of the battery pack. Heat pipe cooling technology boasts advantages such as high equivalent thermal conductivity, fast response speed, and high reliability, making it widely applicable in scenarios requiring high efficiency and uniformity. Phase change material (PCM) cooling, on the other hand, uses PCMs as heat exchange carriers, controlling battery temperature by absorbing or releasing large amounts of heat through latent heat of phase change. PCM cooling can absorb or release large amounts of heat at constant temperatures using latent heat of phase change, offering advantages such as good temperature uniformity and no need for external energy sources. It is widely used in scenarios requiring relief of peak loads or reduction of frequent air conditioning start-ups and shutdowns.

[0004] By employing heat pipes coupled with various heat exchange technologies, such as flat-plate heat pipes with liquid cooling plates, flat-plate heat pipes with phase change materials, and flat-plate heat pipes with air cooling, the temperature rise of the battery pack can be significantly reduced and its temperature uniformity improved compared to a single heat dissipation technology. For prismatic batteries, the flat-plate heat pipe provides a surface for direct contact with the battery. Positioned between two batteries, the heat pipe rapidly transfers the heat generated during charging and discharging to the outside of the battery, where it is then transferred to the environment via air cooling or liquid cooling. In low-temperature environments, the coolant can be heated externally within the battery pack to raise the battery temperature and mitigate the impact of low temperatures on battery performance.

[0005] However, existing battery module structures require multiple flat heat pipes for heat exchange. One end of each heat pipe needs to be attached to a liquid cooling plate to transfer heat, and the pipes are secured with bolts or adhesive. This structure suffers from numerous parts, structural complexity, and multiple installation steps, increasing manufacturing and maintenance difficulty and cost. Furthermore, the limited contact area, uneven contact pressure, and different contact materials between the heat pipes and the liquid cooling plate generate additional thermal resistance, reducing heat exchange efficiency. Therefore, simplifying the battery's thermal management structure, reducing the number of components, lowering assembly difficulty, and improving heat dissipation efficiency are pressing technical challenges that need to be addressed. Summary of the Invention

[0006] (I) Purpose of the Invention

[0007] To address the aforementioned shortcomings and deficiencies of existing technologies, and to solve the technical problems of numerous structural components, complex structures, high thermal resistance between heat pipes and liquid cooling plates, and unsatisfactory heat dissipation in current battery thermal management systems, this invention proposes a battery thermal management structure based on heat pipes and phase change materials, along with its manufacturing method. This structure is a semi-enclosed design that achieves heat exchange and storage through the coupling of heat pipes and phase change materials, while exchanging heat with the external environment via coolant. This enables temperature control of the battery (including cooling and heating), improving battery thermal management performance and maintaining the battery at its optimal operating temperature. The structure is integrally formed using additive manufacturing, which reduces the number of parts, simplifies the assembly process, reduces thermal resistance, lowers the maximum battery temperature, and improves battery temperature uniformity, achieving an integrated structural and functional design that combines load-bearing and thermal control.

[0008] (II) Technical Solution

[0009] To achieve the objective of this invention and solve its technical problems, the present invention adopts the following technical solution:

[0010] The first objective of this invention is to provide a battery thermal management structure based on heat pipes and phase change materials, comprising at least a battery box and a plurality of individual cells discretely arranged in an array along the length of the box. The outer wall shape and dimensional parameters of each individual cell are adapted to the inner wall of the battery box, and the width direction of each individual cell is consistent with the length direction of the battery box, the length direction of each individual cell is consistent with the width direction of the battery box, and at least the length dimension of each individual cell is equivalent to the width dimension of the inner wall of the battery box.

[0011] The battery box is an additively manufactured, one-piece structure. Its bottom wall is integrally formed as a coolant channel interlayer. End plates at both ends along its length and partitions distributed between adjacent individual cells divide the internal space of the battery box into several independent individual cell housing spaces along its length. Each individual cell housing space has a heat insulation sheet at its bottom to prevent heat conduction between the bottom of the individual cell and the top surface of the coolant channel interlayer.

[0012] Each end plate and partition is a plate-shaped structure extending along the height and width of the housing. Each plate-shaped structure is provided with a plurality of flat heat pipes spaced apart along the width of the housing. A porous lattice structure is provided in the space between two adjacent flat heat pipes.

[0013] Each of the aforementioned flat plate heat pipes has an overall structure that is L-shaped or U-shaped, including a first plate-shaped heat exchange functional section extending along the height direction and a second plate-shaped heat exchange functional section formed at the bottom of the first plate-shaped heat exchange functional section and extending along the horizontal direction. The main body of the first plate-shaped heat exchange functional section is completely formed in each of the plate-shaped structures, and heat exchange between the flat plate heat pipe and the individual battery is achieved through close contact with the left and right sides of each individual battery in the width direction. The main body of the second plate-shaped heat exchange functional section is completely formed in the top surface of the coolant flow channel interlayer, and heat exchange between the two is achieved through the coolant in the coolant flow channel interlayer.

[0014] Each of the porous lattice structures has a layered overall structure and is distributed in the space between the first plate-shaped heat exchange functional sections of adjacent flat plate heat pipes in the width direction of the box. The porous lattice space inside is filled with phase change material. The phase change material achieves heat exchange with the individual cells through close contact with the inner wall of the end plate or the left and right side walls of the partition in the width direction. It also achieves heat exchange with the flat plate heat pipes through close contact with the first plate-shaped heat exchange functional sections of each flat plate heat pipe in the width direction of the box.

[0015] In a preferred embodiment of the present invention, a plurality of heat exchange fins are distributed on the bottom surface of the second plate-shaped heat exchange functional section of each of the flat plate heat pipes, extending into the coolant flow channel interlayer and directly exchanging heat with the coolant therein.

[0016] In a preferred embodiment of the present invention, a porous lattice structure is also provided in the coolant flow channel interlayer to enhance the structural strength of the coolant flow channel interlayer space and improve its load-bearing capacity.

[0017] In a preferred embodiment of the present invention, the coolant flow channel interlayer is provided with a coolant inlet and a coolant outlet, and the coolant flow channel interlayer is provided with a plurality of baffles extending along the length of the box body in a staggered manner in the width direction of the box body, so that the coolant entering the internal space of the coolant flow channel interlayer through the coolant inlet flows along the serpentine baffle channel formed by the baffles and then flows out through the coolant outlet.

[0018] In a preferred embodiment of the present invention, in non-low temperature environments, part of the heat generated by the high-rate charging and discharging of the battery is transferred to the coolant in the coolant channel interlayer through each of the flat heat pipes, and the heat is transferred to the external environment through the coolant circulation. Another part of the heat is transferred to the phase change material. The phase change material plays the role of peak shaving and valley filling. The phase change material absorbs heat and undergoes a phase change, and has good temperature retention properties to maintain a constant temperature and suppress the temperature rise of the battery.

[0019] In a preferred embodiment of the present invention, in non-low temperature environments, when the battery is charged and discharged at low rates, the latent heat of phase change in the phase change material is transferred to the coolant in the coolant flow channel interlayer through each of the flat plate heat pipes, and the heat is transferred to the external environment through coolant circulation.

[0020] In a preferred embodiment of the present invention, in a low-temperature environment, the coolant entering the coolant channel interlayer is heated externally. The heat passes through each of the flat heat pipe batteries and the phase change material. After the battery temperature rises to near the normal operating temperature, the coolant circulation is shut off. The latent heat of phase change and the heat generated by battery charging and discharging are released through the phase change material to raise the battery temperature to the optimal operating temperature.

[0021] In a preferred embodiment of the present invention, the basic unit of the porous lattice structure is columnar, tetrahedral, or pyramidal.

[0022] In a preferred embodiment of the present invention, the structural material of the battery box is a metal with high thermal conductivity, the phase change material is paraffin or eicosane, and the coolant in the coolant flow channel interlayer is mineral oil, ethylene glycol, or NOVEC 7000.

[0023] The second objective of this invention is to provide a design method for a battery thermal management structure based on heat pipes and phase change materials, as described in the first objective above, characterized in that the design method includes at least the following design steps:

[0024] SS1. Determine the external dimensions of the battery box based on the size, arrangement, and quantity requirements of each individual battery cell;

[0025] SS2. Select appropriate battery box structural materials, heat pipe working medium, coolant, and phase change material based on the battery's operating ambient temperature;

[0026] SS3. Based on the battery's maximum operating temperature and temperature uniformity requirements, comprehensively calculate the number of heat pipes, cross-sectional dimensions, liquid filling volume, pipe wall thickness, pipe spacing, heat pipe surface fin type, fin size, and fin arrangement parameters.

[0027] SS4. Design the capillary wick microstructure based on the limit forming capability of additive manufacturing. The wick microstructure is designed as a channel structure or a capillary micropore structure.

[0028] SS5. Determine the type, unit size, and relative density of the lattice structure in the porous lattice structure based on the mechanical load it bears;

[0029] SS6. Perform strength and heat transfer performance verification analysis on the battery thermal management structure. If the requirements are not met, repeat steps SS3-6; if the requirements are met, the design process ends.

[0030] The third objective of this invention is to provide a method for manufacturing a battery thermal management structure based on a heat pipe and a phase change material, as described in the first objective above, characterized in that the manufacturing method includes at least the following manufacturing steps:

[0031] SS1. Adjust the model's attitude with the principle of adding the least amount of process support, then set the support structure, slice the layers, set the process path and parameters, and perform laser selective melting additive manufacturing;

[0032] SS2. Heat treatment is performed on the substrate to remove thermal stress, and the battery box is separated from the substrate by wire cutting to remove the support.

[0033] SS3. The surface is treated with sandblasting or manual grinding to remove the adhering powder, while the inner wall surface is treated with abrasive flow or electrochemical polishing to remove the adhering powder.

[0034] SS4. Clean each flat heat pipe to remove all impurities;

[0035] SS5. Vacuum the battery box, heat it to remove gas, and then fill it with working fluid;

[0036] SS6. Weld and seal each flat heat pipe and test it with a helium mass spectrometer. The leak rate must be less than the specified value.

[0037] SS7. Fill the porous lattice structure with phase change material;

[0038] SS8. Conduct load-bearing and heat dissipation performance tests on the battery thermal management structure. Test whether the load-bearing performance, temperature uniformity, thermal response characteristics, heat transfer performance, and critical heat flux density of the battery thermal management structure meet the design requirements. If the requirements are met, the manufacturing is completed.

[0039] (III) Technical Effects

[0040] Compared with the prior art, the battery thermal management structure based on heat pipes and phase change materials of the present invention has the following beneficial and significant technical effects:

[0041] (1) Fewer structural parts, simpler structure, and fewer installation steps. This structure is integrally formed using additive manufacturing, eliminating the need for additional fasteners or connectors. This invention integrates the flat heat pipe and phase change material into the end plate and partition, and integrally forms the coolant flow channel jacket into the bottom wall. This reduces the number of parts, simplifies the assembly process, and lowers manufacturing costs.

[0042] (2) This invention achieves heat exchange and storage through a coupling of two heat exchange technologies: heat pipes and phase change materials (PCMs). Heat exchange between the coolant and the external environment enables temperature control of the battery (including cooling and heating). In non-low-temperature environments, the heat generated by high-rate charging and discharging of the battery is partly transferred to the coolant via the flat heat pipe and then circulated to the external environment. The other part of the heat is transferred to the PCM, which acts as a peak-shaving and valley-filling agent. The PCM absorbs heat and undergoes a phase change, exhibiting excellent temperature retention to maintain a constant temperature and suppress battery temperature rise. During low-rate charging and discharging, the latent heat of phase change in the PCM is transferred to the coolant via the flat heat pipe and then circulated to the external environment. In low-temperature environments, the coolant entering the coolant channel is heated externally. The heat is transferred to the battery via the flat heat pipe and PCM. Once the battery temperature reaches near its normal operating temperature, the coolant circulation is shut off. The latent heat of phase change and the heat generated by battery charging and discharging are released through the PCM, raising the battery temperature to its optimal operating temperature. This ensures that the battery can maintain a suitable temperature range under different environments and operating conditions, thereby improving battery performance and lifespan.

[0043] (3) The battery thermal management structure uses a lattice structure, which has the effect of being lightweight and high-strength, improving the strength of the battery thermal management structure while reducing weight; the lattice structure is filled with phase change material, which utilizes the large latent heat of phase change and constant heat absorption and release temperature of the phase change material, and the lattice structure can enhance the thermal conductivity of the phase change material to further improve the battery temperature uniformity, improve the battery charge and discharge performance and life.

[0044] (4) The additive manufacturing method can form the battery thermal management structure in one step, reduce thermal resistance, reduce processing steps, simplify assembly process, shorten manufacturing cycle, and realize the integration of load-bearing and thermal control structure functions.

[0045] (5) Additive manufacturing can be used to process heat pipe cores with complex structures. The resulting micro-surface can improve wettability and heat pipe performance. Complex and efficient heat dissipation fins can be processed on the contact surface between the heat pipe and the coolant to improve heat exchange performance. Attached Figure Description

[0046] Figure 1 The figure shown is a perspective view of the battery thermal management structure based on heat pipe and phase change material of the present invention.

[0047] Figure 2 The figure shown is a cross-sectional view of the battery thermal management structure based on heat pipes and phase change materials of the present invention.

[0048] Figure 3 The diagram shows the bottom dot matrix structure and heat dissipation fins of the battery thermal management structure of the present invention.

[0049] Figure 4 The diagram shown is a schematic of the bottom coolant flow channel interlayer of the battery thermal management structure of the present invention.

[0050] Figure 5 The diagram shown is a schematic diagram of the battery thermal management structure of the present invention during heat dissipation and heat transfer (left A is the top view, and right B is the front view).

[0051] Figure 6 The diagram shown is a schematic diagram of the battery thermal management structure of the present invention during heat transfer (left A is a top view, and right B is a front view).

[0052] Explanation of reference numerals in the attached figures:

[0053] Battery box 10, end plate 11, separator 12, single cell housing space 13, flat heat pipe 14, porous lattice structure 15, coolant flow channel interlayer 16, coolant inlet 161, baffle 162, heat insulation sheet 17, heat exchange fin 18, single cell 20. Detailed Implementation

[0054] To better understand the present invention, the following embodiments further illustrate its content. Throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The described embodiments are some, but not all, of the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The structure and technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings, providing one embodiment of the present invention.

[0055] like Figures 1-4 As shown, the battery thermal management structure based on heat pipe and phase change material of the present invention includes at least a battery box 10 and a plurality of individual cells 20 arranged in an array at discrete intervals along the length of the box. The outer wall shape and size parameters of each individual cell 20 are adapted to the inner wall of the battery box 10, and the width direction of each individual cell 20 is consistent with the length direction of the battery box 10, and the length direction is consistent with the width direction of the battery box 10. At least the length dimension of each individual cell 20 is equivalent to the width dimension of the inner wall of the battery box 10.

[0056] The battery box 10 is a one-piece structure, with its bottom wall integrally formed as a coolant flow channel interlayer 16. End plates 11 at both ends along its length and partitions 12 distributed between adjacent individual cells 20 divide the internal space of the battery box 10 into several independent individual cell housing spaces 13 along the length of the box. Each individual cell housing space 13 has a heat insulation sheet 17 at its bottom to prevent heat conduction between the bottom of the individual cell 20 and the top surface of the coolant flow channel interlayer 16. Each end plate 11 and partition 12 is a plate-shaped structure extending along the height and width of the box. Each plate-shaped structure contains several flat heat pipes 14 spaced apart along the width of the box. A porous lattice structure 15 is disposed in the space between two adjacent flat heat pipes 14.

[0057] Each flat heat pipe 14 has an L-shaped or U-shaped overall structure, including a first plate-shaped heat exchange functional section extending along the height direction and a second plate-shaped heat exchange functional section formed at the bottom of the first plate-shaped heat exchange functional section and extending along the horizontal direction. The main body of the first plate-shaped heat exchange functional section is completely formed in each plate structure, and heat exchange between the flat heat pipe and the individual battery is achieved through close contact with the left and right sides of each individual battery cell 20 in the width direction. The main body of the second plate-shaped heat exchange functional section is completely formed in the top surface of the coolant flow channel interlayer 16, and heat exchange between the two is achieved through the coolant in the coolant flow channel interlayer 16. Multiple heat exchange fins 18 are distributed on the bottom surface of the second plate-shaped heat exchange functional section of each flat heat pipe 14, extending into the coolant flow channel interlayer 16 and directly exchanging heat with the coolant therein.

[0058] Each porous lattice structure 15 has a layered structure and is distributed in the space between the first plate-shaped heat exchange functional sections of adjacent flat heat pipes 14 in the width direction of the housing. The porous lattice space inside is filled with a phase change material, such as paraffin or eicosane. The phase change material achieves heat exchange with the individual cells through close contact with the inner wall of the end plate or the left and right side walls of the partition in the width direction, and with the flat heat pipes through close contact with the first plate-shaped heat exchange functional sections of each flat heat pipe 14 in the width direction of the housing. A porous lattice structure 15 is also provided in the coolant flow channel interlayer 16, with heat exchange fins 19 that directly exchange heat with the coolant therein. The basic unit of the porous lattice structure 15 is columnar, tetrahedral, or pyramidal.

[0059] The coolant flow channel interlayer 16 is provided with a coolant inlet 161 and a coolant outlet. Several baffles 162 extending along the length of the housing are staggered along the width direction of the interlayer. This allows the coolant entering the internal space of the coolant flow channel interlayer 16 through the coolant inlet 161 to flow along the serpentine flow channel formed by the baffles 162 and then exit through the coolant outlet. The coolant in the coolant flow channel interlayer 16 is mineral oil, ethylene glycol, or NOVEC7000.

[0060] The main working process of the battery thermal management structure of the present invention is as follows:

[0061] 1. In non-low temperature environments, part of the heat generated by the battery during high-rate charging and discharging is transferred to the coolant through heat pipes, and then the coolant circulates to transfer the heat to the environment; another part of the heat is transferred to the phase change material (PCM). The PCM plays a role in peak shaving and valley filling. The PCM absorbs heat and undergoes a phase change, which has excellent temperature retention properties and can maintain a constant temperature, suppressing the battery temperature rise. During low-rate charging and discharging, the latent heat of phase change in the PCM is transferred to the coolant through heat pipes, and then the coolant circulates to transfer the heat to the environment.

[0062] 2. In low-temperature environments, the coolant is heated externally, and the heat is transferred to the battery and phase change material through heat pipes. After the battery temperature rises to near the normal operating temperature, the coolant circulation can be shut off. The latent heat of phase change and the heat generated by battery charging and discharging are released through the phase change material to raise the battery temperature to the optimal operating temperature.

[0063] The design steps of the battery thermal management structure of the present invention are as follows:

[0064] 1. Determine the external dimensions of the battery thermal management structure based on the battery's size, arrangement, and quantity requirements;

[0065] 2. Select appropriate structural materials (aluminum, etc.), heat pipe working medium (methanol, ethanol, propanol, etc.), coolant (mineral oil, ethylene glycol, NOVEC 7000, etc.) and phase change materials (paraffin, eicosane, etc.) according to the battery's operating environment temperature;

[0066] 3. Based on the battery's maximum operating temperature and temperature uniformity requirements, comprehensively calculate the following parameters: number of heat pipes, cross-sectional dimensions (heat pipe width between 10 and 40 mm), liquid filling volume, pipe wall thickness (pipe wall thickness between 0.2 and 1 mm), pipe spacing, heat pipe surface fin type (rectangular straight fins, rectangular pin fins, cylindrical pin fins, triangular pin fins, etc.), fin size, and fin arrangement dimensions.

[0067] 4. Design the capillary wick microstructure based on the limiting forming capability of additive manufacturing. The wick can be designed as a rectangular channel or other shaped channel (e.g., Ω-shaped, trapezoidal, triangular, etc.) as well as a capillary micropore structure.

[0068] 5. Determine the type, element size, and relative density of the lattice structure based on the mechanical loads it bears;

[0069] 6. Perform strength and heat transfer performance verification analysis on the battery thermal management structure. If the requirements are not met, repeat steps 3-6; if the requirements are met, the design process ends.

[0070] The battery thermal management structure of the present invention is manufactured in the following steps:

[0071] 1. Adjust the model's posture to minimize the need for additional process support, then set the support structure, slice the layers, set the process path and parameters, and perform laser selective melting additive manufacturing;

[0072] 2. Heat treatment is performed on the substrate to remove thermal stress, and the battery thermal management structure is separated from the substrate by wire cutting to remove the support;

[0073] 3. Remove adhering powder from the surface by sandblasting or manual grinding; remove adhering powder from the inner wall surface by abrasive flow or electrochemical polishing.

[0074] 4. Clean the heat pipes to remove all impurities;

[0075] 5. Vacuum heating is performed on the battery thermal management structure to remove gas, and then the working fluid is filled in;

[0076] 6. The heat pipe is welded and sealed, and then leaked using a helium mass spectrometer. The leak rate must be less than the specified value.

[0077] 7. Fill the lattice structure with phase change material;

[0078] 8. Conduct load-bearing and heat dissipation performance tests on the battery thermal management structure, and test whether the load-bearing performance, temperature uniformity, thermal response characteristics, heat transfer performance, and critical heat flux density of the battery thermal management structure meet the design requirements.

[0079] The objectives of this invention have been fully and effectively achieved through the above embodiments. Those skilled in the art will understand that this invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments described above. Although the invention has been described with reference to what is currently considered the most practical and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments, and any modifications that do not depart from the functional and structural principles of the invention will be included within the scope of the claims.

Claims

1. A battery thermal management structure based on heat pipes and phase change materials, comprising at least a battery box and a plurality of individual cells discretely arranged in an array along the length of the box, wherein the outer wall shape and size parameters of each individual cell are adapted to the inner wall of the battery box, and the width direction of each individual cell is consistent with the length direction of the battery box, the length direction of each individual cell is consistent with the width direction of the battery box, and at least the length dimension of each individual cell is equivalent to the width dimension of the inner wall of the battery box, characterized in that, The battery box is an additively manufactured, one-piece structure. Its bottom wall is integrally formed as a coolant channel interlayer. End plates at both ends along its length and partitions distributed between adjacent individual cells divide the internal space of the battery box into several independent individual cell housing spaces along its length. Each individual cell housing space has a heat insulation sheet at its bottom to prevent heat conduction between the bottom of the individual cell and the top surface of the coolant channel interlayer. Each end plate and partition is a plate-shaped structure extending along the height and width of the housing. Each plate-shaped structure is provided with a plurality of flat heat pipes spaced apart along the width of the housing. A porous lattice structure is provided in the space between two adjacent flat heat pipes. Each of the aforementioned flat plate heat pipes has an overall structure that is L-shaped or U-shaped, including a first plate-shaped heat exchange functional section extending along the height direction and a second plate-shaped heat exchange functional section formed at the bottom of the first plate-shaped heat exchange functional section and extending along the horizontal direction. The main body of the first plate-shaped heat exchange functional section is completely formed in each of the plate-shaped structures, and heat exchange between the flat plate heat pipe and the individual battery is achieved through close contact with the left and right sides of each individual battery in the width direction. The main body of the second plate-shaped heat exchange functional section is completely formed in the top surface of the coolant flow channel interlayer, and heat exchange between the two is achieved through the coolant in the coolant flow channel interlayer. Each of the porous lattice structures has a layered overall structure and is distributed in the space between the first plate-shaped heat exchange functional sections of adjacent flat plate heat pipes in the width direction of the box. The porous lattice space inside is filled with phase change material. The phase change material achieves heat exchange with the individual cells through close contact with the left and right sides in the width direction of each individual cell through the inner wall of the end plate or the left and right side walls of the partition. It also achieves heat exchange with the flat plate heat pipes through close contact with the first plate-shaped heat exchange functional sections of each flat plate heat pipe in the width direction of the box. On the bottom surface of the second plate-shaped heat exchange functional section of each of the flat plate heat pipes, multiple heat exchange fins are distributed, extending into the coolant flow channel interlayer and directly exchanging heat with the coolant therein. The coolant flow channel interlayer is also provided with a porous lattice structure to enhance the structural strength of the coolant flow channel interlayer space and improve its load-bearing capacity. The coolant flow channel interlayer is provided with a coolant inlet and a coolant outlet, and the coolant flow channel interlayer is provided with a number of baffles extending along the length of the box body in a staggered manner in the width direction of the box body, so that the coolant entering the internal space of the coolant flow channel interlayer through the coolant inlet flows along the serpentine baffle channel formed by the baffles and then flows out through the coolant outlet.

2. The battery thermal management structure based on heat pipes and phase change materials according to claim 1, characterized in that, In non-low temperature environments, the heat generated by the high-rate charging and discharging of the battery is partly transferred to the coolant in the coolant channel interlayer through the flat heat pipes, and then transferred to the external environment through coolant circulation. Another part of the heat is transferred to the phase change material. The phase change material plays the role of peak shaving and valley filling. The phase change material absorbs heat and undergoes a phase change, which has good temperature retention and can maintain a constant temperature, suppressing the temperature rise of the battery.

3. The battery thermal management structure based on heat pipes and phase change materials according to claim 1, characterized in that, In non-low temperature environments, when the battery is charged and discharged at low rates, the latent heat of phase change in the phase change material is transferred to the coolant in the coolant flow channel interlayer through each of the flat plate heat pipes, and the heat is transferred to the external environment through coolant circulation.

4. The battery thermal management structure based on heat pipes and phase change materials according to claim 1, characterized in that, In low-temperature environments, the coolant entering the coolant channel interlayer is heated externally. The heat is transferred through each of the flat heat pipes and the phase change material. After the battery temperature rises to near the normal operating temperature, the coolant circulation is shut off. The latent heat of phase change and the heat generated by battery charging and discharging are released through the phase change material to raise the battery temperature to the optimal operating temperature.

5. The battery thermal management structure based on heat pipes and phase change materials according to claim 1, characterized in that, The basic unit of the porous lattice structure is columnar, tetrahedral, or pyramidal.

6. A design method for a battery thermal management structure based on heat pipes and phase change materials as described in any one of claims 1 to 5, characterized in that, The design method includes at least the following design steps: SS1. Determine the external dimensions of the battery box based on the size, arrangement, and quantity requirements of each individual battery cell; SS2. Select appropriate battery box structural materials, heat pipe working medium, coolant, and phase change material based on the battery's operating ambient temperature; SS3. Based on the battery's maximum operating temperature and temperature uniformity requirements, comprehensively calculate the number of heat pipes, cross-sectional dimensions, liquid filling volume, pipe wall thickness, pipe spacing, heat pipe surface fin type, fin size, and fin arrangement. SS4. Design the capillary wick microstructure based on the limiting forming capability of additive manufacturing. The wick microstructure is designed as a channel structure or a capillary micropore structure. SS5. Determine the type, unit size, and relative density of the lattice structure in the porous lattice structure based on the mechanical load it bears; SS6. Perform strength and heat transfer performance verification analysis on the battery thermal management structure. If the requirements are not met, repeat steps SS3 to SS6; if the requirements are met, the design process ends.

7. A method for manufacturing a battery thermal management structure based on a heat pipe and phase change material as described in any one of claims 1 to 5, characterized in that, The manufacturing method includes at least the following manufacturing steps: SS1. Adjust the model's attitude with the principle of adding the least amount of process support, and then set the support structure, layer slicing, process path and parameters, and laser selective melting additive manufacturing; SS2. Heat treatment is performed on the substrate to remove thermal stress, and the battery box is separated from the substrate by wire cutting to remove the support. SS3. The surface is cleaned by sandblasting or manual grinding to remove the adhering powder, and the inner wall surface is cleaned by abrasive flow or electrochemical polishing to remove the adhering powder. SS4. Clean each flat heat pipe to remove all impurities; SS5. Vacuum heating is performed on each flat heat pipe to remove gas, and then the working fluid is filled in; SS6. Weld and seal each flat heat pipe and test for leaks using a helium mass spectrometer. The leak rate must be less than the specified value. SS7. Fill the porous lattice structure with phase change material; SS8. Conduct load-bearing and heat dissipation performance tests on the battery thermal management structure. Test whether the static compression, static bending, dynamic compression, temperature uniformity, thermal response characteristics, heat transfer performance, and critical heat flux density of the battery thermal management structure meet the design requirements. If the requirements are met, the manufacturing is completed.

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