JP7546608B2 - Thermal management system and method for lithium battery pack - Google Patents

Description

The present invention relates to a thermal management system and method for a lithium battery pack, and is in the field of heat dissipation for battery packs in electric vehicles.

Thermal management of lithium battery packs is not only critical to battery life, but also to battery safety.

Air-cooling technology, a conventional method for managing the heat in battery packs, is not only unable to meet the protection rating requirements for lithium battery packs, but also has little value at present because the large temperature difference between the inlet and outlet of the air-cooling system creates a large temperature difference between the batteries, causing significant damage to the lithium batteries.

The thermal management method of conventional lithium battery packs with high protection grades generally adopts a liquid cooling mode, and currently, the liquid-cooled bottom plate adopted by most manufacturers is a single liquid cooling plate installed only at the bottom of the battery module. The single liquid cooling plate heat dissipation method at the bottom of the battery module can cause a very large temperature difference between the top and bottom of the battery cell, which can cause great damage to the battery during rapid charging and discharging and low-temperature preheating. Tesla is the only company that adopts a liquid cooling mode on the entire side surface of all batteries. However, currently, direct cooling is performed using antifreeze or refrigerant as the liquid refrigerant, the latter being equivalent to a direct expansion evaporator. Direct expansion cooling using refrigerant has a refrigerant temperature that is too low, which can cause a serious low-temperature shock to the battery, generating an extremely large temperature difference inside the battery and causing great damage to the battery, and is of little practical value. Antifreeze is the most commonly used antifreeze, which contains water and has many welds on the bottom plate, so the welds are easily damaged during use, which can cause the antifreeze to leak from inside. Tesla uses full-side liquid cooling tubes, whose welds are on the outside of the battery pack, but once a collision occurs, the liquid cooling tubes between the battery cells will be destroyed, which can also cause the antifreeze to leak. The welds are distributed on all sides, so there is a high possibility that the welds will be damaged. In any case, if the leaked antifreeze comes into contact with the batteries in the battery pack, it will cause a short circuit in the battery pack, resulting in a serious safety accident.

To solve the problems of the prior art, such as high hidden dangers, low heat dissipation efficiency, and large damage to the battery in the thermal management system of a lithium battery pack, the present invention proposes a thermal management system and method for a lithium battery pack.

The technical solutions of the present invention are as follows:

That is, the thermal management system for a lithium battery pack according to the present invention includes a battery pack consisting of one or more layers of vertical batteries and/or battery modules , a battery pack case providing a closed structure surrounding the battery pack , a heat exchange system , and a micro heat pipe array bonded to the front and both side surfaces of the battery pack , the micro heat pipe array being arranged inclined laterally at an angle of not less than 1° with respect to the horizontal, with its upper end bonded to one side of the battery pack to form a condensation section, its lower end bonded to the other side of the battery pack to form an evaporation section, and an intermediate section between the upper end and lower end bonded to the front of the battery pack to form a heat conduction section, a heater being provided on the outer surface of the evaporation section, and the heat exchange system being bonded to the outer surface of the battery pack case at a location corresponding to the condensation section.

Preferably, the heat exchange system comprises a liquid-cooled plate-tube heat exchanger attached to at least the outer surface of the micro heat pipe array at a location corresponding to the condensation portion, connected to an external cooling system of the battery pack, and having a sealed substrate, the heat exchange system being completely physically isolated from the battery and/or battery module via the battery pack case; or a heat exchange system comprising a liquid-cooled plate-tube heat exchanger attached to at least the outer surface of the micro heat pipe array at a location corresponding to the condensation portion, connected to an external cooling system of the battery pack, and having a sealed substrate, and an air-cooled module having air-cooled fins therein and a fan on a side surface, the substrate of the air-cooled fins being attached to the outside of the liquid-cooled plate-tube heat exchanger and having a sealed substrate, the heat exchange system being completely physically isolated from the battery and/or battery module via the battery pack case; or an external air-cooled module attached to the outer surface of the micro heat pipe array at a location corresponding to the condensation portion, having air-cooled fins therein, and having a fan on a side surface.

Preferably, the substrate of the liquid-cooled plate-tube heat exchanger is connected or welded to the outer surface of the battery pack case by a seal ring, and the battery pack case is IP67 rated.

Preferably, a compressible, thermally conductive spacer is provided between the micro heat pipe array and the battery and/or battery module.

More preferably, the system includes an automatic control system and a battery cell temperature detection unit, the automatic control system being connected to the battery cell temperature detection unit, the electric vehicle cooling system and the heater, respectively.

Preferably, the micro heat pipe array is a flat heat conductor having a porous structure formed by extruding a metal material, has multiple micro heat pipes arranged in parallel inside but not connected to each other and operating independently, each micro heat pipe has a hydraulic diameter of 0.2-3.0 mm, and the internal phase change working medium is a non-conductive medium.

In addition, the thermal management method for a lithium battery pack according to the present invention is characterized in that it employs the above-mentioned thermal management system and dissipates heat absorbed by the micro heat pipe array by conducting it to a heat exchange system attached to the outer surface of the portion of the micro heat pipe array corresponding to the condensation portion .

Preferably, the heat exchange system is a liquid-cooled plate-tube heat exchanger connected to a battery pack external cooling system, and when the detected battery cell temperature is higher than a first set value, the control system automatically starts the cooling system, drives and starts the liquid-cooled plate-tube heat exchanger, and dissipates heat from the battery pack, and when the battery cell temperature is lower than the first set value, the cooling system stops supplying cooling to the liquid-cooled plate-tube heat exchanger.

More preferably, when the battery temperature is lower than the second set temperature, the heater that is in direct or indirect contact with the micro heat pipe array is heated, and the battery is heated by the micro heat pipe array, at which time the cooling system stops operating.

Preferably, the heat exchange system is a liquid-cooled plate-tube heat exchanger connected to the battery pack external cooling system and an external air-cooled fin equipped with a fan, and heat is conducted via a heat-conducting partition plate to the liquid-cooled plate-tube heat exchanger and the external air-cooled fin attached to the outer surface of the heat-conducting partition plate. When the detected battery cell temperature reaches a first set value, the control system first turns on the fan, and the heat is automatically dissipated by the external air-cooled fin. When the detected battery cell temperature becomes higher than a third set value, the control system automatically starts the cooling system, drives and starts the liquid-cooled plate-tube heat exchanger, and dissipates heat from the battery cell simultaneously with the external air-cooled fin.

More preferably, when the battery temperature is lower than the second set value, a heater that is in direct or indirect contact with the micro heat pipe array is heated and heat is exchanged with the battery and/or battery module via the micro heat pipe array, and at this time the fan and cooling system stop operating.

Preferably, the heat exchange system is an external air-cooling module, and when the detected battery cell temperature is higher than a first set value, the control system automatically starts the fan and automatically dissipates heat through the fins of the external air-cooling module, and when the battery cell temperature is lower than the first set value, the fan stops operating.

More preferably, when the battery temperature is lower than the second set value, a heater that is in direct or indirect contact with the micro heat pipe array is heated and heat is exchanged with the battery and/or battery module via the micro heat pipe array, and at this time the fan stops operating.

The advantageous technical effects of the present invention are as follows:

The thermal management system for the lithium battery pack of the present invention employs an indirect liquid cooling method, or two types of cooling methods, such as liquid cooling and air cooling, or an air cooling method, to manage the temperature of the battery pack, and a micro heat pipe array thermal conductor is attached laterally to the surface of the battery (battery cell) and/or battery module placed horizontally or vertically, and heat is transported via a heat conductive partition plate to a heat exchange system, i.e., a liquid-cooled plate-tube heat exchanger and/or an external air-cooled module connected to the cooling system.

When the micro heat pipe array is vertical, each group is attached to the front of the vertical battery (battery cell) and/or battery module to form a heat conductive section, and both ends are bent and then the vertical parts are attached to the two sides of the battery and/or battery module to form an evaporation section and a condensation section, respectively, and the condensation section is further attached to a heat conductive partition plate, so that the heat of the battery is transferred to the condensation section via the evaporation section and the heat conductive section, and the contact area between the micro heat pipe and the battery and/or battery module and the heat conductive partition plate is increased, and the heat conduction efficiency is greatly improved. Meanwhile, when multiple groups are stacked and arranged in sequence, the above-mentioned Only the front side of the battery and/or battery module is attached to the micro heat pipe array, and the back side is attached to the micro heat pipe array attached to the front side of the adjacent group, ensuring that both the front and back sides of each group of battery and/or battery module are attached to the micro heat pipe array with fewer micro heat pipes, thereby making it possible to dissipate heat from the battery cells located inside with fewer micro heat pipes and heat exchange systems, ensuring a uniform temperature of the battery pack placed vertically, high heat dissipation efficiency, and low cost.

The micro heat pipe array is a flat heat conductor with a porous structure formed by extruding a metal material. It has multiple micro heat pipes arranged in parallel inside but not connected to each other. The hydraulic diameter of each micro heat pipe is only 0.2-3.0 mm, and in some cases even smaller. The tube wall pressure bearing capacity is extremely high, so there is no need to consider the leakage problem. The phase change working medium is a non-conductive medium in small amounts, so even if it is damaged and leaks in extreme circumstances, the battery will not be damaged. The heat conductive partition plate also serves as a protective case for the battery cell, isolating the liquid-cooled plate-tube heat exchanger and the substrate of the external air-cooling fin from the battery pack. The substrate of the liquid-cooled plate-tube heat exchanger is sealed by sealing means such as a seal ring or welding, completely physically isolating it from the battery cell in the case. This effectively prevents leakage of antifreeze in the liquid-cooled plate-tube heat exchanger, ensures that the protection rating of the battery pack reaches IP67 waterproof and dustproof rating, and there is no risk of liquid contamination in the air-cooling system.

In the battery pack thermal management system of the present invention, when the heat exchange system is a liquid-cooled plate-tube heat exchanger, when the temperature of the battery cell is higher than a first set value, for example 35°C, the control system automatically starts the liquid cooling system of the vehicle, and the micro heat pipe array evaporator (or the evaporator and heat conduction section) attached to the surface of the battery cell and/or battery module absorbs heat and conducts it to the micro heat pipe array condenser, and the condenser conducts the heat through the battery pack case to the liquid-cooled plate-tube heat exchanger attached to it for dissipation, and the liquid-cooled plate-tube heat exchanger is generally connected to the electric vehicle cooling system, but a dedicated cooling system may also be used, and the coolant circulation of the liquid cooling system is stopped when the temperature of the battery cell is lower than the set value.

When the heat exchange system is a liquid-cooled plate-tube heat exchanger and an external air-cooling module, when the detected battery temperature is higher than a first set value, for example 35°C, the fan is first automatically started to dissipate heat through the external air-cooling fins, the micro heat pipe array evaporator (or the evaporator and heat conduction part) attached to the surface of the battery cell and/or battery module absorbs heat and transfers it to the micro heat pipe array condenser, and the condenser transfers the heat to the external air-cooling fins attached to it through the battery pack case to dissipate the heat, thereby realizing non-cooling energy-saving heat dissipation in seasons other than the hot summer season, and allowing the electric vehicle to operate Regardless of whether the battery is in a standby state or a stopped state, the air-cooling system is in a standby state, and therefore automatically dissipates heat when the battery generates heat during the electric vehicle stop period, i.e., during the period when the cooling system is not in operation, greatly reducing the serious risk of thermal runaway, etc. Also, in extreme conditions such as high summer temperatures, when the detected battery temperature is higher than the third set value, if the heat dissipation by the external air-cooling fins cannot meet the lithium battery thermal control conditions, for example at 40°C, the liquid-cooling system is automatically started to dissipate heat from the battery, and when the battery temperature is lower than 35°C, the liquid-cooling system stops operating, thereby enabling significant energy savings. The liquid-cooled plate-and-tube heat exchanger is generally connected to the electric vehicle cooling system, but a dedicated cooling system may also be used.

When the heat exchange system is an external air-cooling module, when the temperature of the lithium battery is higher than a first set value, for example 35°C, the fan is automatically started, and the micro heat pipe array evaporator (or the evaporator and heat-conducting part) attached to the surface of the battery cell and/or battery module absorbs heat and conducts it to the micro heat pipe array condenser, and the condenser conducts the heat to the external air-cooling fin attached to it through the battery pack case to dissipate the heat, realizing non-cooling energy-saving heat dissipation, thereby enabling uniform heat dissipation and significant energy saving. Regardless of whether the electric vehicle is in operation or stopped, the air-cooling system is in standby, i.e., the fan can be automatically started to dissipate heat even when the battery generates heat during the electric vehicle stop period, greatly reducing the serious risk of thermal runaway, etc.

An electric heater is installed on the evaporator part (or the lower surface) of the micro heat pipe array, and when the temperature of the battery cell is lower than a second set value, e.g., 0°C, the control system automatically turns off the cooling system and supplies power to the electric heater, which generates heat rapidly after being powered, and the heat is rapidly and evenly transferred to other parts of the micro heat pipe array, further preheating the battery and/or battery module rapidly and evenly.

The thermally conductive spacer has functions such as thermal conduction, electrical insulation, and ensuring good contact between the micro heat pipe array and the battery.

The air passage of the external air-cooling module is a plenum chamber type or a uniform fan distribution type, which ensures that the temperature difference between the air entering and exiting the air-cooling module is small, and ensures that the temperature difference between all batteries is no higher than 5°C.

Preferably, when the micro heat pipe array is vertical, each of the micro heat pipe arrays is arranged with a horizontal inclination, with an inclination angle β of not less than 1°, with one end attached to the side of the battery and/or battery module and located on the upper side being a condensation section, and one end attached to the other side of the battery and/or battery module and located on the lower side being an evaporation section, whereby the working medium in the condensation section of the micro heat pipe is rapidly returned to the evaporation section by gravity, increasing the thermal conduction efficiency of the micro heat pipe.

To sum up, the present invention effectively combines a micro heat pipe array capable of efficient heat conduction with a liquid cooling and/or air cooling method, and automatically controls the activation method of the cooling mode according to the temperature. Furthermore, according to the relative positioning relationship between the micro heat pipe array and the battery or battery module, an external liquid-cooled plate-tube type heat exchanger and/or an external air cooling fin are installed on the outside of each battery pack, which can effectively conduct and dissipate the temperature inside the battery, prevent excessively high temperatures, ensure a uniform battery temperature, have high heat dissipation efficiency, and separate dry and wet, solving the problems of conventional liquid cooling modules that have high hidden dangers and great damage to the battery.

FIG. 2 is a schematic diagram of a thermal management structure of a vertical cell. FIG. 2 is a schematic diagram of the thermal management structure of a vertical cell from another viewing angle. FIG. 1 is a schematic diagram of a thermal management structure of a vertical battery module formed by connecting two battery cells in series. FIG. 13 is a schematic diagram of the thermal management structure of a vertical battery module formed by connecting two battery cells in series, viewed from another viewing angle. FIG. 2 is a schematic diagram of the thermal management structure of all modules in a vertical battery pack. FIG. 13 is a schematic diagram of the thermal management structure of all modules in a vertical battery pack from another viewing angle. FIG. 1 is a plan view showing the layout of a micro heat pipe array in a vertical type single cell. FIG. 1 is a plan view showing the layout of a micro heat pipe array in a vertical battery module formed by connecting two battery cells in series. FIG. 2 is a schematic diagram of an exploded structure of the first embodiment of the present invention. FIG. 10 is a schematic diagram of the assembly of FIG. 9 . FIG. 1 is an enlarged top view of a cell or battery module according to Example 1-5. FIG. 11 is a schematic diagram of an exploded structure of the second embodiment of the present invention. FIG. 13 is a schematic diagram of the assembly of FIG. 12 . FIG. 11 is a schematic diagram of the assembled embodiment 3. FIG. 13 is a schematic diagram of an exploded structure of the fourth embodiment of the present invention. FIG. 16 is a schematic diagram of the assembly of FIG. 15 . FIG. 13 is a schematic diagram of Example 5. FIG. 13 is a schematic diagram of an exploded structure of the sixth embodiment of the present invention. FIG. 19 is a schematic diagram of FIG. 18 after assembly. FIG. 1 is a schematic diagram of a cross section of one end of a battery of Example 6-10. FIG. 13 is a schematic diagram of an exploded structure of Example 7. FIG. 22 is a schematic diagram of FIG. 21 after assembly. FIG. 23 is a schematic diagram of FIG. 22 from another angle. FIG. 13 is a schematic diagram of Example 8 after assembly. FIG. 13 is a schematic diagram of an exploded structure of Example 9. FIG. 26 is a schematic diagram of FIG. 25 after assembly. FIG. 27 is a schematic diagram of FIG. 26 from another angle. FIG. 23 is a schematic diagram of Example 10 after assembly. FIG. 23 is a schematic cross-sectional view of a battery unit according to an eleventh embodiment.

To make the present invention more clearly understandable, the present invention will be described in detail with reference to drawings and specific examples.

As shown in Figures 1-10, the thermal management system of this embodiment has a vertical battery and/or battery module, and includes a battery pack and a liquid-cooled plate-tube heat exchanger 7 attached to the outside of a battery pack case 6. The battery pack is formed by sequentially stacking two single battery cells 1 and three battery modules 2, in which there is one single battery cell 1 at the front and one at the back, with three battery modules 2 sandwiched between them, for a total of eight battery cells connected in series. The single battery cells 1 and battery modules 2 can be replaced with a flexible packing battery module having an external structural strength case, which is made by combining soft packing single batteries. Each battery cell is placed vertically with the battery electrodes facing upward, and a micro heat pipe array is attached laterally to the surface of the battery cell. The micro heat pipe array is a thermal conductor with enhanced thermal conduction effect, and is a flat thermal conductor with a porous structure formed by extruding a metal material. It has multiple micro heat pipes arranged in parallel inside but not connected to each other, and a phase-change working medium is sealed inside the micro heat pipes, and the phase-change working medium transfers heat by repeatedly absorbing heat by evaporation and releasing heat by condensation. In this embodiment, two micro heat pipe arrays are attached to the front of each group of the single battery cell 1 and battery module 2, and the two micro heat pipe arrays may be distributed at an interval between each other or may be closely arranged. The back surface of the battery and/or battery module is attached to the micro heat pipe array attached to the front of the adjacent single battery cell 1 or battery module 2 stacked on each other. The micro heat pipe array thermal conductive part 4 is attached to the front of the battery cell and the back surface of the adjacent battery cell. The micro heat pipe array thermal conductive part 4 serves as an evaporation part when the battery needs to be cooled or dissipate heat, and serves as a condensation part when the battery needs to be heated or increase in temperature. Both ends of each micro heat pipe array are bent to the sides of the single battery cell 1 or battery module 2, and the vertical parts are attached to two sides of the single battery cell 1 and battery module 2 of each group by thermal conductive silica gel, respectively, to form the micro heat pipe array evaporation part 3 and the micro heat pipe array condensation part 5, and are attached to the inside of the corresponding battery pack case 6. The battery pack case 6 surrounds the battery pack to form a closed structure, and is attached to the micro heat pipe array evaporator 3 and the micro heat pipe array condenser 5, and at least the part attached to the micro heat pipe array condenser 5 is a heat conductive partition plate. The liquid-cooled plate tube heat exchanger 7 is attached to at least the outer surface of the heat conductive partition plate to exchange heat with the micro heat pipe array condenser 5 through the heat conductive partition plate. The liquid-cooled plate tube heat exchanger 7 has a refrigerant inlet 8 and a refrigerant outlet 9 on the substrate, and is connected to the cooling system of the electric vehicle to form a liquid cooling system. One side surface of the substrate of the liquid-cooled plate tube heat exchanger 7 is welded to the outer surface of the battery pack case 6, but may be connected by a seal ring, which realizes complete physical isolation of the liquid-cooled plate tube heat exchanger 7 from the internal battery cells and ensures that the protection rating of the battery pack reaches IP67.

As shown in Figures 7-8, preferably, each of the micro heat pipe arrays is arranged at a lateral inclination, with an inclination angle β greater than 1°, 10° in this embodiment, with one end located on the upper side and attached to the side of the single battery cell 1 or battery module 2 being the micro heat pipe array condensation section 5, and one end located on the lower side and attached to the other side of the single battery cell 1 or battery module 2 being the micro heat pipe array evaporation section 3.

As shown in FIG. 11, an electric heater 14 is further installed on the outer surface of the micro heat pipe array evaporator 3, and when the electric heater 14 is activated, the micro heat pipe evaporator can be considered as a micro heat pipe heating section. A compressible and deformable thermally conductive spacer 13 is installed between the micro heat pipe array and the single battery cell 1 and the battery module 2, and the thermally conductive spacer has functions such as thermal conduction, electrical insulation, and ensuring good contact between the micro heat pipe array and the battery.

The thermal management system of this embodiment further includes an automatic control system and a battery cell temperature detection unit, and the automatic control system is connected to the battery cell temperature detection unit and the cooling system of the electric vehicle, respectively.

In the liquid-cooled thermal management method for a lithium battery pack with wet and dry separation using the above thermal management system, the micro heat pipe array evaporator 3 attached to one side of the single battery cell 1 and the battery module 2 and the micro heat pipe array thermal conductive part 4 attached to the front absorb heat from the single battery cell 1 and the battery module 2 and conduct it to the micro heat pipe array condenser 5 located on the side of the single battery cell 1 and the battery module 2. The condenser then conducts the heat to the thermal conductive partition plate attached to it, and the thermal conductive partition plate transfers the heat to the outer surface of the thermal conductive partition plate. The heat is conducted to and dissipated by the liquid-cooled plate-tube heat exchanger 7, which is combined with the liquid-cooled plate-tube heat exchanger 7 and connected to the cooling system of the electric vehicle; at the same time, the heat-conducting partition plate physically isolates the internal battery cell from the external cold source; when the temperature of the battery cell detected by the detection unit is higher than the first set value of 35°C, the control system automatically starts the cooling system of the electric vehicle to dissipate heat from the battery cell through the liquid-cooled plate-tube heat exchanger 7, the heat-conducting partition plate and the micro heat pipe array, and dissipate the heat of the battery cell; when the temperature of the battery cell is lower than 35°C, the cooling system of the electric vehicle stops cooling to the liquid cooling system.

When the ambient temperature is lower than a second set value, e.g., 0°C, the control system automatically turns off the cooling system and supplies power to the electric heater 14, e.g., a PTC thermistor or an electric heating film, installed in the micro heat pipe array evaporator section 3. The PTC thermistor or the electric heating film generates heat rapidly after being powered, and the heat is transferred rapidly and uniformly to the micro heat pipe array thermal conduction section 4 and the condenser section 5 via the micro heat pipe array evaporator section 3, and further preheats the single battery cell 1 and the battery module 2 rapidly and uniformly.

As shown in Figures 1-8 and 12-13, the thermal management system of this embodiment includes a battery pack, a liquid-cooled plate-tube heat exchanger 7 attached to the outside of the battery pack case 6, and an external air-cooling module 10, and the battery and/or battery module are vertical. The battery pack and battery pack case are the same as those of Example 1. The liquid-cooled plate-tube heat exchanger 7 is attached to at least the outer surface of a heat-conducting partition plate and exchanges heat with the micro heat pipe array condenser 5 through the heat-conducting partition plate, and one side surface of the substrate is welded to the outer surface of the battery pack case 6, but may also be connected by a seal ring, thereby achieving complete physical isolation of the liquid-cooled plate-tube heat exchanger 7 and the external air-cooling module 10 from the internal battery cells and ensuring that the protection rating of the battery pack reaches IP67. The liquid-cooled plate-type heat exchanger 7 has a refrigerant inlet 8 and a refrigerant outlet 9 on the substrate, and is connected to the cooling system of the electric vehicle to form a liquid cooling system for the battery. The external air-cooling module 10 is attached to the surface of the liquid-cooled plate-type heat exchanger 7 as an air-cooling system, has multiple air-cooling fins 11 inside, and has a fan 12 on one side of the air-cooling fins 11.

As shown in FIG. 11, a compressible and deformable thermally conductive spacer 13 is installed between the micro heat pipe array and the single battery cell 1 and battery module 2. The thermally conductive spacer 13 has functions such as thermal conduction, electrical insulation, and ensuring good contact between the micro heat pipe array and the battery. An electric heater 14 is further installed on the outer surface of the micro heat pipe array evaporator 3. When the electric heater 11 is activated, the micro heat pipe evaporator may be considered as a micro heat pipe heating section.

The thermal management system of this embodiment further includes an automatic control system and a battery cell temperature detection unit, and the automatic control system is connected to the battery cell temperature detection unit, the cooling system of the electric vehicle, the electric heater 14, and the fan 12, respectively.

In the safe and energy-saving lithium battery pack dual mode thermal management method using the thermal management system, the micro heat pipe array evaporator 3 attached to the side of the single battery cell 1 and the battery module 2 and the micro heat pipe array thermal conduction part 4 attached to the front and/or back absorb the heat of the single battery cell 1 and the battery module 2 and exchange heat with the micro heat pipe array condenser 5 located on the other side of the single battery cell 1 and the battery module 2, and then the condenser conducts the heat to the thermal conduction partition plate attached thereto, and the thermal conduction partition plate conducts the heat to the liquid-cooled plate-tube heat exchanger 7 and the external air-cooling module 10 attached to the outer surface of the thermal conduction partition plate and connected to the cooling system of the electric vehicle. When the temperature of the battery cell detected by the detection unit is higher than a first set value, for example 35°C, the fan 12 is automatically started to dissipate heat, and when the detected battery temperature is higher than a second set value, for example 40°C, the liquid cooling system is started to dissipate heat from the battery, and when the battery temperature is lower than 35°C, the liquid cooling system stops operating.

When the ambient temperature is lower than a third set value, e.g., 0°C, the control system automatically turns off the cooling system and supplies power to the electric heater 14 installed in the micro heat pipe array evaporator 3, e.g., a PTC thermistor or an electric heating film. The PTC thermistor or the electric heating film generates heat rapidly after being powered, and the micro heat pipe array evaporator 3 absorbs and evaporates the heat, which is then rapidly and evenly transferred to the thermal conduction section 4 and the condensation section 5 of the micro heat pipe array, and further rapidly and uniformly preheats the single battery cell 1 and the battery module 2.

In order to ensure that the temperature difference between the air entering and leaving the external air-cooling module 10 is small and that the temperature difference between all batteries is not higher than 5°C, in this embodiment, the air passage of the external air-cooling module 10 is in the form of a plenum chamber 15 as shown in Figure 14, and the other structures and operating methods are similar to those of embodiment 2, and the temperature difference between the air entering and leaving the air-cooling module is small and that the temperature difference between all batteries is not higher than 5°C.

As shown in Figures 1-8 and 15-16, the thermal management system of this embodiment includes a battery pack and an external air-cooling module 10 attached to the outside of the battery pack case 6, and the battery and/or battery module are vertical. The battery pack and the battery pack case are the same as those of the first embodiment. The external air-cooling module 10 is installed outside the battery pack, and is attached to at least the outer surface of a heat-conducting partition plate to exchange heat with the micro heat pipe array condenser 5 through the heat-conducting partition plate. One side surface of the substrate is welded to the outer surface of the battery pack case 6, but may be connected by a seal ring, which realizes complete physical isolation of the external air-cooling module 7 from the internal battery cells and ensures that the protection rating of the battery pack reaches IP67.

As shown in FIG. 11, a compressible and deformable thermally conductive spacer 13 is installed between the micro heat pipe array and the single battery cell 1 and battery module 2. The thermally conductive spacer 13 has functions such as thermal conduction, electrical insulation, and ensuring good contact between the micro heat pipe array and the battery. An electric heater 14 is further installed on the outer surface of the micro heat pipe array evaporator 3. When the electric heater 14 is activated, the micro heat pipe evaporator may be considered as a micro heat pipe heating section.

The vertical lithium battery pack air-cooled thermal management system with a high degree of protection according to this embodiment further includes an automatic control system and a battery cell temperature detection unit, and the automatic control system is connected to the battery cell temperature detection unit and the electric heater 14.

In the heat management method of the air-cooled battery pack with a high degree of protection using the above heat management system, the micro heat pipe array heat conductive part 4 attached to the front of the single battery cell 1 and the battery module 2 and the micro heat pipe array heat conductive part attached to the side absorb and evaporate the heat of the single battery cell 1 and the battery module 2, and conduct it to the micro heat pipe array condensation part 5 located on the other side of the single battery cell 1 and the battery module 2. The condensation part then conducts the heat to the heat conductive partition plate attached to it, and the heat conductive partition plate conducts the heat to the external air cooling module 7 attached to the outer surface of the heat conductive partition plate. When the temperature of the battery cell detected by the detection unit is higher than 35°C, the control system automatically starts the external air cooling module 7 and turns on the fan 9 to dissipate heat from the battery cell through the external air cooling module 7, the heat conductive partition plate and the micro heat pipe array, and dissipates the heat of the battery cell. When the temperature of the battery cell is lower than 35°C, the external air cooling module 6 is turned off and does not dissipate heat.

When the ambient temperature is lower than a second set value, e.g., 0°C, the control system automatically turns off the cooling system and supplies power to the electric heater 14 installed in the micro heat pipe array evaporator 3, e.g., a PTC thermistor or an electric heating film. After being powered, the PTC thermistor or the electric heating film rapidly generates heat, and the heat is rapidly and uniformly transferred to the thermal conduction section 4 and the condensation section 5 of the micro heat pipe array through the micro heat pipe array evaporator 3, and further rapidly and uniformly preheats the single battery cell 1 and the battery module 2.

In order to ensure that the temperature difference between the air entering and leaving the external air-cooling module 10 is small and that the temperature difference between all batteries is no higher than 5°C, in this embodiment, the air passage of the external air-cooling module 10 is a plenum chamber 15 type as shown in Figure 17, and the other structures and operation methods are similar to those of embodiment 4.

As shown in Fig. 18-20, the battery pack thermal management system of this embodiment includes a battery pack and a liquid-cooled plate-tube heat exchanger 7 attached to the outside of a battery pack case 6, the battery and/or battery module is horizontal, and the battery cells in the battery pack are divided into a total of four layers, with three in each layer in the vertical and horizontal directions. Two groups of micro heat pipe arrays 16 extending in the horizontal direction are attached to the upper and lower surfaces of the three single battery cells 1 in the horizontal direction of each layer. The micro heat pipe arrays 16 are attached to the surfaces of the single battery cells 1 by thermally conductive silica gel and are distributed at intervals from each other, but may be closely arranged. The part of the micro heat pipe array 16 attached to the battery unit 5 is an evaporation part, and the part whose length is longer than that of each group of battery cells forms a protruding part 17, which is a condensation part. A battery pack case 6 is installed outside the battery pack, and the battery pack case 6 is surrounded to form a closed structure. The protruding portion 17 of each of the micro heat pipe arrays 16 is bent in a direction perpendicular to the plane of the micro heat pipe array, and the vertical portion is attached to the inside of the battery pack case 1, and the portion corresponding to the condensation portion in the battery pack case 6 is a heat conductive partition plate. The liquid-cooled plate-tube heat exchanger 7 is attached to at least the outer surface of the heat conductive partition plate, and exchanges heat with the protruding portion 17 of the micro heat pipe array 16 through the heat conductive partition plate, and one side surface of the substrate is welded to the outer surface of the battery pack case 6, but may be connected by a seal ring, which realizes complete physical isolation of the liquid-cooled plate-tube heat exchanger 7 from the internal battery, and ensures that the protection grade of the battery pack reaches IP67. The liquid-cooled plate-tube heat exchanger 7 is connected to the cooling system of the electric vehicle to form a liquid cooling system for the battery.

As shown in FIG. 18, the protruding portions of the micro heat pipe array 16 located on the upper plane of the battery cells of each group are bent downward, and those located on the lower plane are bent upward, so that both surround the single battery cells 5 of each group inward and stop the outward displacement of the single battery cells 1 located on the outside.

The liquid-cooled plate-tube heat exchanger 2 has a refrigerant inlet 8 and a refrigerant outlet 9 on the substrate and is connected to the electric vehicle cooling system.

Also, as shown in FIG. 20, a compressible and deformable thermally conductive spacer 13 may be provided between the micro heat pipe array 16 and the single battery cell 1.

The individual battery cells 5 may be replaced with a flexible packing battery module made up of two or more soft packing individual batteries combined together and having an external structural strength case.

This embodiment further includes an automatic control system and a battery cell temperature detection unit, and the automatic control system is connected to the battery cell temperature detection unit and the electric vehicle cooling system, respectively.

During use, the evaporative portion of the micro heat pipe array 6 attached to both side surfaces of the battery unit 5 of each group absorbs the heat of each battery unit 5 and transfers it to the condensing portion formed by the protruding portion located at one end of the micro heat pipe array 6, the condensing portion then transfers the heat to the heat conductive partition plate 8 attached to it, and the heat conductive partition plate 8 transfers the heat to the liquid-cooled plate-tube heat exchanger 2 attached to the outer surface of the heat conductive partition plate 8 and connected to the electric vehicle cooling system, when the temperature of the battery unit 5 detected by the detection unit is higher than 35°C, the control system automatically starts the electric vehicle cooling system to dissipate heat from the battery cells through the liquid-cooled plate-tube heat exchanger 2, the heat conductive partition plate and the micro heat pipe array, and dissipates the heat from the battery cells, and when the temperature of the battery unit 5 is lower than 35°C, the electric vehicle cooling system stops cooling to the liquid cooling system. As shown in FIG. 3, an electric heater 14, such as an electric heating film, may be installed on the lower surface of the micro heat pipe array. When the battery temperature is lower than the set temperature, the electric heating film 8 is heated and the battery is heated by the micro heat pipe array, at which time the cooling system stops operating.

As shown in Figures 21-23, the thermal management system of the lithium battery pack of this embodiment includes a battery pack, a liquid-cooled plate-tube heat exchanger 7 attached to the outside of the battery pack case 6, and an external air-cooling fin 11 equipped with a fan 12, and the battery and/or battery module are horizontal. The battery pack and the battery pack case are the same as those of Example 6, and the battery pack case 1 has a heat-conducting partition plate at the location corresponding to the condenser. The liquid-cooled plate-tube heat exchanger 7 is attached to at least the outer surface of the heat-conducting partition plate and exchanges heat with the protruding portion 17 of the micro heat pipe array 16 through the heat-conducting partition plate 8, and one side surface of the substrate is welded to the outer surface of the battery pack case 6, but may be connected by a seal ring, which realizes complete physical isolation of the liquid-cooled plate-tube heat exchanger 2 from the internal battery unit 5 and ensures that the protection grade of the battery pack reaches IP67. The liquid-cooled plate-tube heat exchanger 2 is connected to the cooling system of the electric vehicle to form a liquid cooling system for the battery. The substrate of the external air-cooling fins 11 is attached to the outside of the liquid-cooled plate-tube heat exchanger 7. In order to keep the temperature difference between the air entering and leaving the air-cooling module small, it is better to distribute the fans 12 as evenly as possible.

As shown in FIG. 21, the protruding portions 17 of the micro heat pipe arrays 16 located on the upper plane of the single cells 1 of each group are bent downward, and those located on the lower plane are bent upward, both of which surround the battery unit inward to stop the outward displacement of the single cells 1 located on the outside.

The liquid-cooled plate-tube heat exchanger 7 has a refrigerant inlet 8 and a refrigerant outlet 9 on the substrate and is connected to the electric vehicle cooling system.

Also, as shown in FIG. 20, a compressible and deformable thermally conductive spacer 13 may be provided between the micro heat pipe array 16 and the single battery cell 1.

The individual battery cells 1 may be replaced with a flexible packing battery module made up of two or more soft packing individual batteries combined together and having an external structural strength case.

This embodiment further includes an automatic control system and a battery cell temperature detection unit, and the automatic control system is respectively connected to the battery cell temperature detection unit, the fan, and the electric vehicle cooling system.

During use, the evaporative portion of the micro heat pipe array 16 attached to both side surfaces of the single battery cell 1 of each group absorbs heat from each single battery cell 1 and transfers it to the condensing portion formed by the protruding portion 17 located at one end of the micro heat pipe array 16, the condensing portion then transfers the heat to the thermally conductive partition plate attached to it, and the thermally conductive partition plate transfers the heat to the liquid-cooled plate-tube heat exchanger 7 and external air-cooled fins 11 attached to the outer surface of the thermally conductive partition plate and connected to the electric vehicle cooling system. Regardless of whether the electric vehicle is in operation or stopped, the air-cooling system is in standby mode. When the temperature of the lithium battery reaches the first set value of 35°C, the fan 12 is automatically started without starting the liquid-cooling system. The heat is transferred to the external air-cooling fins 11 via the liquid-cooled plate-tube heat exchanger 7 for heat exchange, and the heat is automatically dissipated by the air-cooling fins. This realizes non-cooling energy-saving heat dissipation in seasons other than the hot summer season, and automatic heat dissipation when the battery heats up during the electric vehicle stop period, that is, the cooling system operation stop period, and greatly reduces serious risks such as thermal runaway. In addition, in extreme conditions such as hot summer, for example, when the third set value of 40°C is reached, if the heat dissipation by the external air-cooling fins cannot meet the lithium battery heat control conditions, liquid cooling is automatically performed by the vehicle's cooling system, and when the system cools down to the first set value of 35°C, the liquid-cooling system is turned off. As a result, the overall temperature reduction requirement and safety are achieved, while significant energy savings are also achieved.

As shown in FIG. 20, an electric heater 14, such as an electric heating film, may be further installed on the outer surface of the micro heat pipe array, and when the battery temperature is lower than the set temperature, the electric heating film is heated and the battery is heated by the micro heat pipe array, at which time the cooling system stops operating.

In order to ensure that the temperature difference between the air entering and leaving the air cooling module is small and that the temperature difference between all batteries is no higher than 5°C, the air passage of the air cooling module in this embodiment is a plenum chamber type as shown in Figure 24, and the other structures and operating methods are similar to those of Example 7.

As shown in Figs. 25-27, the thermal management system of the lithium battery pack of this embodiment includes a battery pack and an external air-cooling module 10 attached to the outside of the battery pack case 6, the battery and/or battery module are horizontal, and the external air-cooling module includes a fan 12 and air-cooling fins 11. The battery pack and the battery pack case are the same as those of the sixth embodiment, in which the part of the battery pack case 1 corresponding to the condensation part is a heat-conducting partition plate. The external air-cooling module 10 exchanges heat with the protruding part 17 of the micro heat pipe array 16 through the heat-conducting partition plate, and one side surface of the substrate is welded to the outer surface of the battery pack case 6, but may be connected by a seal ring, which realizes complete physical isolation of the external structure from the internal single battery cell 1 and ensures that the protection grade of the battery pack reaches IP67. In order to ensure a small temperature difference between the air entering and leaving the external air-cooling module 10, it is better to distribute the fans 12 as evenly as possible.

As shown in FIG. 25, the protruding portions of the micro heat pipe array 16 located on the upper plane of the single battery cells 1 of each group are bent downward, and those located on the lower plane are bent upward, both of which surround the entire single battery cells 1 inward and stop the outward displacement of the single battery cells 1 located on the outside.

Also, as shown in FIG. 31, a compressible and deformable thermally conductive spacer 7 may be provided between the micro heat pipe array 16 and the single battery cell 1.

The individual battery cells 1 may be replaced with a flexible packing battery module made up of two or more soft packing individual batteries combined together and having an external structural strength case.

This embodiment further includes an automatic control system and a battery cell temperature detection unit, and the automatic control system is connected to the battery cell temperature detection unit and the fan 12, respectively.

During use, the evaporator of the micro heat pipe array 16 attached to both sides of the single battery cell 1 of each group absorbs heat from each single battery cell 1 and transfers it to the condenser formed by the protruding part located at one end of the micro heat pipe array 16, the condenser then transfers the heat to the heat conductive partition plate attached thereto, the heat conductive partition plate transfers the heat to the external air-cooling module 10, and the air-cooling fins 11 dissipate the heat through the action of the fan 12. Regardless of whether the electric vehicle is in operation or stopped, the air-cooling system is in standby mode, and when the temperature of the lithium battery reaches the first set value of 35°C, the fan 12 is controlled by the control system to automatically start up and transfer the heat to the external air-cooling fins 11 for automatic heat dissipation, which not only realizes non-cooling energy-saving heat dissipation during operation, but also realizes automatic heat dissipation for the heat generated by the battery during the stop period of the electric vehicle, greatly reducing the serious risk of thermal runaway and achieving significant energy saving.

As shown in FIG. 20, an electric heater 14, for example an electric heating film 8, may be further installed on the outer surface of the micro heat pipe array, and when the battery temperature is lower than the set temperature, the electric heating film is heated and the battery is heated by the micro heat pipe array, at which time the fan stops operating.

In order to ensure that the temperature difference between the air entering and leaving the air cooling module is small and that the temperature difference between all batteries is no higher than 5°C, in this embodiment, the air passage of the air cooling module is a plenum chamber type as shown in Figure 28, and the other structures and operating methods are similar to those of Example 9.

As shown in Figure 29, the internal structure of the battery in this embodiment has a micro heat pipe array only on the bottom side, and has protruding parts 61 on both sides that are both bent upwards, and the other structures and principles are the same as those of Examples 6-10.

The above is merely a preferred specific embodiment of the present invention and does not limit the scope of protection of the present invention. Any modifications that a person skilled in the art can easily conceive without departing from the technical scope disclosed in the present invention are included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should conform to the scope of the claims.

Reference Signs List 1 Single battery cell 2 Battery module 3 Micro heat pipe array evaporator section 4 Micro heat pipe array thermal conduction section 5 Micro heat pipe array condenser section 6 Battery pack case 7 Liquid-cooled plate-tube heat exchanger 8 Refrigerant inlet 9 Refrigerant outlet 10 External air-cooling module 11 Fins 12 Fan 13 Thermally conductive spacer 14 Electric heater 15 Plenum chamber 16 Micro heat pipe array 17 Protruding section

Claims (15)

A battery pack including one or more layers of vertical batteries and/or battery modules , a battery pack case providing a closed structure surrounding the battery pack , a heat exchange system , and a micro heat pipe array bonded to the front and both sides of the battery pack ,
the micro heat pipe array is arranged inclined in the lateral direction at an angle of not less than 1° with respect to the horizontal, its upper end is attached to one side surface of the battery pack to form a condensation portion, its lower end is attached to the other side surface of the battery pack to form an evaporation portion, and an intermediate portion between the upper end and the lower end is attached to a front surface of the battery pack to form a heat conduction portion;
A heater is provided on the outer surface of the evaporation section,
A thermal management system for a lithium battery pack , wherein the heat exchange system is attached to an outer surface of the battery pack case at a location corresponding to the condensation portion. The thermal management system of claim 1, characterized in that the heat exchange system is a liquid-cooled plate-tube heat exchanger, which is attached to an outer surface of at least a portion of the micro heat pipe array corresponding to the condenser portion and connected to an external cooling system of a battery pack, the substrate of the liquid-cooled plate-tube heat exchanger being sealed and completely physically isolated from the battery and/or battery module via the battery pack case. 2. The thermal management system according to claim 1, wherein the heat exchange system is a liquid-cooled plate-tube heat exchanger and an external air-cooling module, the liquid-cooled plate-tube heat exchanger is attached to at least the outer surface of the micro heat pipe array corresponding to the condensation portion and connected to a cooling system outside the battery pack, the external air-cooling module has air-cooling fins inside and a fan on the side, the substrate of the air-cooling fins is attached to the outside of the liquid-cooled plate-tube heat exchanger, the substrate of the liquid-cooled plate-tube heat exchanger and the substrate of the external air-cooling module are both sealed, and are completely physically isolated from the battery and/or battery module via the battery pack case. 2. The thermal management system of claim 1, wherein the heat exchange system is an external air-cooling module, which is in close contact with the outer surface of the portion of the micro heat pipe array corresponding to the condensation portion, has air-cooling fins inside, and has a fan on the side. The thermal management system according to claim 2 , wherein the substrate of the liquid-cooled plate-tube heat exchanger is connected or welded to the outer surface of the battery pack case by a seal ring, and the battery pack case is IP67 rated. The thermal management system of claim 1 , further comprising a compressible thermally conductive spacer disposed between the micro heat pipe array and the battery pack. The thermal management system of claim 1 , further comprising an automatic control system and a battery cell temperature detection unit, the automatic control system being connected to the battery cell temperature detection unit, the electric vehicle cooling system and the heater. The thermal management system according to claim 1, characterized in that the micro heat pipe array is a flat thermal conductor having a porous structure formed by extruding a metal material, has a plurality of micro heat pipes arranged in parallel inside but not connected to each other and operating independently, each micro heat pipe has a hydraulic diameter of 0.2-3.0 mm, and the internal phase change working medium is a non-conductive medium. A thermal management method for a lithium battery pack, comprising: adopting the thermal management system according to any one of claims 1 to 8; and conducting and dissipating heat absorbed by a micro heat pipe array to a heat exchange system attached to an outer surface of the micro heat pipe array at a location corresponding to the condensation portion. The method according to claim 9, wherein the heat exchange system is a liquid-cooled plate-tube heat exchanger connected to a battery pack external cooling system, and when the detected battery cell temperature is higher than a first set value, the control system automatically starts the cooling system, drives and starts the liquid-cooled plate-tube heat exchanger to dissipate heat from the battery pack, and when the battery cell temperature is lower than the first set value, the cooling system stops supplying cooling to the liquid-cooled plate-tube heat exchanger. The method according to claim 10, characterized in that when the battery temperature is lower than a second set temperature, a heater in direct or indirect contact with the micro heat pipe array is heated, and the battery is heated by the micro heat pipe array, at which time the cooling system stops operating. The method according to claim 9, wherein the heat exchange system is a liquid-cooled plate-tube heat exchanger connected to a battery pack external cooling system and an external air-cooled fin equipped with a fan, and heat is conducted through a heat conductive partition plate to the liquid-cooled plate-tube heat exchanger and the external air-cooled fin attached to the outer surface of the heat conductive partition plate; when the detected battery cell temperature reaches a first set value, the control system first turns on the fan to automatically dissipate heat through the external air-cooled fin; when the detected battery cell temperature is greater than a third set value, the control system automatically starts the cooling system to drive and start the liquid-cooled plate-tube heat exchanger, and dissipate heat from the battery cell simultaneously with the external air-cooled fin. The method according to claim 12, characterized in that when the battery temperature is lower than a second set value, a heater in direct or indirect contact with the micro heat pipe array is heated and heat is exchanged with the battery and/or battery module through the micro heat pipe array, and at this time the fan and cooling system stop operating. The method according to claim 9, wherein the heat exchange system is an external air-cooling module, and when the detected battery cell temperature is higher than a first set value, the control system automatically starts a fan to automatically dissipate heat through the fins of the external air-cooling module, and when the battery cell temperature is lower than the first set value, the fan stops working. The method according to claim 14, characterized in that when the battery temperature is lower than a second set value, a heater in direct or indirect contact with the micro heat pipe array is heated and heat is exchanged with the battery and/or battery module through the micro heat pipe array, and at this time the fan stops operating.