Vehicle battery thermal management device and method

Abstract

The invention discloses a vehicle battery thermal management device and method, and relates to the technical field of battery temperature management, the vehicle battery thermal management device comprises a heat conduction frame, a plurality of separation areas are arranged in the heat conduction frame, the separation areas are used for placing batteries of a battery pack, and gaps between the separation areas and the batteries are filled with phase change materials; the direct cooling plate is connected with the bottom of the heat conduction frame, a heat exchange channel in the direct cooling plate is externally connected with a heat pump assembly, and refrigerants can circulate between the heat exchange channel and the heat pump assembly. According to the vehicle battery thermal management device and method provided by the invention, the energy consumption is low during high-temperature heat dissipation, and the temperature uniformity is good.

Description

Technical Field

[0001] The present invention relates to the technical field of battery temperature management, and particularly to a vehicle battery thermal management device and method. Background Art

[0002] The power system of electric vehicles generally uses power batteries. The stability of the working state, cycle life, and endurance of power batteries are all important factors that need to be considered. Lithium-ion batteries have become the first choice for power system design due to their memoryless effect, long cycle life, and high energy density. Temperature is an important factor affecting the life and safety of lithium-ion batteries. Generally, lithium batteries should operate within the range of 25 - 40 °C.

[0003] Traditional lithium battery thermal management methods mainly include air cooling, liquid cooling, phase change material cooling, etc. However, these traditional cooling methods have some limitations. For example, air cooling and phase change material cooling systems can no longer meet the current thermal management needs of high-energy batteries. The liquid cooling system has poor temperature uniformity, high energy consumption, and complex structure.

[0004] Based on the above problems, the direct cooling system has become a new choice for electric vehicle thermal management due to its high degree of integration. However, the direct cooling system will cause uneven heat dissipation of the battery, that is, poor temperature uniformity, resulting in uneven degradation of the battery and thermal safety problems.

[0005] In order to overcome the limitations of the above thermal management methods, it is urgent to design a technical solution with low energy consumption and good temperature uniformity during high-temperature heat dissipation. Summary of the Invention

[0006] The purpose of the present invention is to provide a vehicle battery thermal management device and method to solve the problems existing in the above prior art, with low energy consumption and good temperature uniformity during high-temperature heat dissipation.

[0007] To achieve the above purpose, the present invention provides the following solutions:

[0008] The present invention provides a vehicle battery thermal management device, including:

[0009] A heat conduction frame, which is provided with a plurality of partition areas inside. The partition areas are used to place the batteries of the battery pack, and phase change materials are filled in the gaps between the partition areas and the batteries.

[0010] A direct cooling plate, which is connected to the bottom of the heat conduction frame. The heat exchange channels inside the direct cooling plate are externally connected to a heat pump assembly, and a refrigerant can circulate between the heat exchange channels and the heat pump assembly.

[0011] In high-temperature heat dissipation conditions, turn on the heat pump assembly for active direct cooling. The phase change material absorbs the radial heat of the battery pack and transfers the heat in time through the heat-conducting frame. The direct cooling plate absorbs the longitudinal heat of the battery pack, and guarantees the heat dissipation efficiency to the greatest extent through the phase change of the refrigerant, while ensuring the stability of the battery pack and the consistency of temperature during the heat dissipation process. In addition, the direct cooling plate can absorb the heat transferred by the phase change material and the heat-conducting frame, and restore the heat storage capacity of the phase change material in time. Under moderate temperature conditions, thermal management without energy consumption can be achieved only through the phase change material and the heat-conducting frame. In a low-temperature environment, the direct cooling plate quickly preheats the battery pack through the heat pump assembly, and the phase change material and the heat-conducting frame ensure the temperature consistency of the process. When the battery stops working for a short time in winter, the heat stored in the phase change material can prevent the battery pack from dissipating heat quickly, and preheat it twice, thereby achieving energy-saving effects. In addition, when the passenger compartment needs additional heat, the heat pump assembly can absorb the heat of the battery pack and the composite phase change material through the direct cooling plate, further improving the winter endurance.

[0012] Preferably, it further comprises a thermal pad, which is sleeved on the outside of the battery of the battery pack, and the inner wall of the thermal pad is in contact with the side wall of the battery; the phase change material is filled between the inner wall of the separation area and the outer wall of the thermal pad.

[0013] Preferably, the phase change material is a composite phase change material; the composite phase change material is made of a mixture of foam metal and paraffin. The addition of foam metal improves the problem of poor thermal conductivity of paraffin, while also ensuring the stability of the structure during the cycle. In addition, the soft nature of the phase change material also ensures that the batteries will not squeeze each other during exercise, causing safety problems.

[0014] Preferably, a battery management system is also included, and the battery management system includes a current sensor, a voltage sensor and a temperature sensor arranged on the battery pack, and the battery management system is used to monitor the working status of the battery.

[0015] Preferably, the heat-conducting frame includes a plurality of first partitions arranged in parallel, a plurality of second partitions are penetrated through the plurality of first partitions, a plurality of second partitions are arranged in parallel, and the second partitions are arranged at an angle to the first partitions. The heat-conducting frame is made of aluminum alloy, which ensures that the heat of the phase change material can be timely discharged and dissipated by external air convection heat exchange or absorbed by the direct cooling plate or utilized by other systems. In addition, the heat-conducting frame ensures the mechanical stability of the entire structure, prevents the phase change material from melting and leaking, and by separating the batteries in the battery pack, it is beneficial to the uniform heat dissipation of the battery, which plays a positive role in preventing thermal runaway of the battery.

[0016] Preferably, the heat exchange channels in the direct cooling plate are arranged in a serpentine structure or a meandering structure. The direct cooling plate is made of aluminum-magnesium-manganese alloy, which has the characteristics of high strength, corrosion resistance, good thermal conductivity, and light weight. In addition, the internal heat exchange flow channels are arranged in a serpentine structure or a meandering structure, which can effectively reduce the energy consumption caused by the flow resistance of the direct cooling plate.

[0017] Preferably, the phase change temperature of the composite phase change material is 35-40 °C.

[0018] Preferably, one end of the battery pack is attached to the outer surface of the direct cooling plate close to the heat conduction frame.

[0019] The present invention also provides a vehicle battery thermal management method, which includes the following steps:

[0020] Step 1, when the temperature sensor monitors that the temperature of the battery pack exceeds the liquid phase limit temperature of the phase change material, turn on the heat pump assembly for active direct cooling;

[0021] Step 2, when the temperature sensor monitors that the temperature of the battery pack is within the phase change temperature range of the phase change material, achieve heat dissipation without energy consumption through the phase change material and the heat conduction frame;

[0022] Step 3, in a low-temperature environment, the direct cooling plate preheats the battery pack through the heat pump assembly. During the preheating process, heat is transferred through the phase change material and the heat conduction frame to ensure the temperature consistency of the battery pack.

[0023] Preferably, in Step 1, the process of the heat pump assembly performing active direct cooling includes:

[0024] The phase change material absorbs the radial heat of each battery of the battery pack and transfers the heat to the direct cooling plate through the heat conduction frame. The direct cooling plate absorbs the longitudinal heat of the battery pack; the heat pump assembly drives the refrigerant to circulate between the heat exchange channel and the heat pump assembly, and dissipates heat at the direct cooling plate through the phase change of the refrigerant to ensure the temperature consistency of the battery pack during the heat dissipation process.

[0025] The present invention has achieved the following technical effects compared with the prior art:

[0026] In the present invention, multiple batteries of a battery pack are separated into multiple separated areas by a heat-conducting frame, and each battery of the battery pack is wrapped with a phase-change material; in a high-temperature heat dissipation condition, the phase-change material absorbs the radial heat of each battery in the battery pack and transfers the heat in time through the heat-conducting frame, so that the temperatures of the multiple batteries in the battery pack are uniform. The direct cooling plate is attached to one end of the battery pack and can absorb the longitudinal heat of the battery pack. At the same time, the direct cooling plate can also absorb the heat conducted by the heat-conducting frame; then, the direct cooling plate ensures the heat dissipation efficiency to the greatest extent through the phase change of the refrigerant, and at the same time ensures the consistency of the stable temperature of the battery pack during the heat dissipation process. In a situation where the temperature is moderate, when the battery temperature is within the phase-change temperature range of the phase-change material, the heat pump assembly can be not started, and the battery pack can be cooled only by the heat exchange between the phase-change material and the heat-conducting frame and the battery pack, so that the heat management of the battery pack without energy consumption can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a schematic structural diagram of a vehicle battery thermal management device in one or some embodiments of the present invention;

[0029] Figure 2 It is a schematic structural diagram of a battery pack of a vehicle battery thermal management device in one or some embodiments of the present invention;

[0030] Figure 3 It is a schematic structural diagram of a heat-conducting frame of a vehicle battery thermal management device in one or some embodiments of the present invention;

[0031] Figure 4 It is a schematic structural diagram of a heat-conducting pad of a vehicle battery thermal management device in one or some embodiments of the present invention;

[0032] Figure 5 It is a schematic structural diagram of a composite phase-change material of a vehicle battery thermal management device in one or some embodiments of the present invention;

[0033] Figure 6 It is a schematic structural diagram of a direct cooling plate of a vehicle battery thermal management device in one or some embodiments of the present invention.

[0034] In the figure: 1 - battery pack, 2 - composite phase-change material, 3 - battery management system, 4 - heat-conducting pad, 5 - heat-conducting frame, 501 - first partition, 502 - second partition, 6 - direct cooling plate, 601 - heat exchange channel. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] The object of the present invention is to provide a vehicle battery thermal management device and method to solve the problems existing in the above-mentioned prior art, with low energy consumption during high-temperature heat dissipation and good temperature uniformity.

[0037] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] In the prior art, the thermal management system of pure electric vehicles has high energy consumption and poor temperature uniformity during high-temperature heat dissipation. To solve this problem, the present invention provides a vehicle battery thermal management device for thermal management of lithium-ion battery packs, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6As shown in the figure, it includes a heat-conducting frame 5, which is provided with a plurality of partition areas for placing the batteries of the battery pack 1; a direct cooling plate 6 is connected to the bottom of the heat-conducting frame 5, and a heat exchange channel 601 in the direct cooling plate 6 is externally connected to a heat pump assembly, and a refrigerant can circulate between the heat exchange channel 601 and the heat pump assembly; one battery of the battery pack 1 is placed in each partition area, so that the plurality of partition areas arrange the plurality of batteries of the battery pack 1 in sequence, and a phase change material is filled in the gap position between the partition area and the battery. In one embodiment, the phase change material is a composite phase change material 2, which is made by mixing foam metal and paraffin, and the phase change temperature is 35-40 °C, further improving the thermal conductivity of the phase change material and ensuring the stability of the shape of the phase change material during the phase change process. The thickness dimension of the phase change material filling is 2 mm, and the characteristics of the phase change material can also ensure that the batteries in the battery pack 1 will not be squeezed against each other during the driving of the vehicle, causing possible safety problems. In the present invention, the plurality of batteries of the battery pack 1 are separated into a plurality of partition areas by the heat-conducting frame 5, and each battery of the battery pack 1 is wrapped with a phase change material; in the high-temperature heat dissipation condition, the phase change material absorbs the radial heat of each battery in the battery pack 1 and transfers the heat in time through the heat-conducting frame 5, so that the temperatures of the plurality of batteries in the battery pack 1 are uniform. The direct cooling plate 6 is attached to one end of the battery pack 1, which can absorb the longitudinal heat of the battery pack 1, and at the same time, the direct cooling plate 6 can also absorb the heat conducted by the heat-conducting frame 5; then the direct cooling plate 6 ensures the heat dissipation efficiency to the greatest extent through the phase change of the refrigerant, and at the same time ensures the consistency of the stable temperature of the battery pack 1 during the heat dissipation process. The heat pump assembly and the working principle of the heat pump assembly are both prior arts. The heat pump assembly is a device that transfers the heat energy of a low-temperature heat source to a high-temperature heat source, and its working principle is based on the thermodynamic principle, and forces the heat to flow from a low-temperature object to a high-temperature object in a reverse cycle manner. The heat pump can obtain a large amount of heat supply by consuming a small amount of net work in the reverse cycle (such as electric energy), so as to effectively utilize the difficult-to-apply low-grade heat energy to achieve the purpose of energy conservation. The refrigerant flowing between the heat exchange channel 601 in the direct cooling plate 6 and the heat pump assembly is converted between gaseous and liquid states and absorbs and releases heat, so that the direct cooling plate 6 can absorb the heat of the battery pack 1 or transfer the released heat to the battery pack 1.

[0039] The direct cooling plate 6 is the core component in the direct cooling type thermal management technology, and it mainly absorbs or releases heat through the phase change of the refrigerant. The refrigerant is compressed into a high-temperature and high-pressure gas in the compressor, that is, the heat pump assembly, and then enters the condenser to be condensed into a normal-temperature and high-pressure liquid. The liquid refrigerant then enters the expansion valve, and after expansion, it becomes a low-temperature and low-pressure two-phase flow (a mixture of liquid and gas) and enters the direct cooling plate (i.e., the evaporator). Inside the direct cooling plate 6, the two-phase flow completely becomes gaseous after absorbing heat, and then returns to the inside of the compressor through the pipeline to complete a complete cycle.

[0040] In this embodiment, the metal foam selected is copper foam; by adding copper foam, on the one hand, the problem of poor thermal conductivity of paraffin is improved, and at the same time, the stability of the structure during the cycle is ensured. In addition, the soft characteristics of the phase change material also ensure that during the movement process, the batteries will not be squeezed against each other to cause safety problems.

[0041] Under the condition of moderate temperature, when the battery temperature is within the phase change temperature range of the phase change material, the heat pump assembly can be not started, and only the heat exchange between the phase change material and the heat conduction frame 5 and the battery pack 1 is carried out to realize the cooling of the battery pack 1, and then the thermal management of the battery pack 1 without energy consumption can be realized.

[0042] In order to perform more accurate thermal management on the battery pack 1, in one embodiment, a battery management system 3 is designed, that is, a BMS monitoring device, which also belongs to the prior art. The BMS monitoring device is a key component, which is responsible for monitoring the state of the battery pack, including voltage, current, temperature, etc., to ensure the safe operation of the battery, optimize the performance and extend the service life. The BMS monitoring device can also realize the balanced charging of the battery pack, prevent individual batteries from being overcharged or over-discharged, so as to protect the safety of the entire battery pack. The battery management system 3 includes a current sensor, a voltage sensor and a temperature sensor arranged on the battery pack 1. The battery management system 3 is used to monitor the working state of the battery and can trigger the control end of the heat pump assembly according to the battery state, so that the heat pump assembly is turned on or off to ensure that the battery pack 1 is in a stable working state. The overall structure of the present invention has the characteristics of high integration and automation. All thermal management conditions can be evaluated by the BMS monitoring device for appropriate thermal management to achieve maximum energy saving.

[0043] In order to separate the multiple batteries of the battery pack 1, so that the heat dissipation of the batteries in the battery pack 1 is more uniform, the heat conduction frame 5 in this embodiment is made of aluminum alloy material, which has the characteristics of high melting point and high thermal conductivity, and the thickness dimension is 1 mm, ensuring excellent adhesion and stability with the direct cooling plate 6 and the composite phase change material 2; its structure includes a plurality of first partitions 501 arranged in parallel, and a plurality of second partitions 502 penetrate through the plurality of first partitions 501. The plurality of second partitions 502 are arranged in parallel, and the second partitions 502 are arranged at an angle with the first partitions 501. In one embodiment, the second partitions 502 are perpendicularly arranged with the first partitions 501, so that the partition areas separated by the first partitions 501 and the second partitions 502 are all rectangular structures.

[0044] In one embodiment, the heat exchange channels 601 in the direct cooling plate 6 are arranged in a serpentine structure or a meandering structure, which increases the heat exchange area of the direct cooling plate 6. The direct cooling plate 6 is made of aluminum-magnesium-manganese alloy, which has the characteristics of high strength and light weight, and has good compatibility with the composite phase change material 2 while ensuring good thermal conductivity.

[0045] To avoid direct contact between the battery and the phase change material, which may damage the side wall of the battery by the phase change material, in one embodiment, a heat conductive pad 4 is sleeved on the outer wall of the battery. The heat conductive pad 4 is made of silicone with good heat conductivity, has a thickness dimension of 1 mm, and has the advantages of low density, good flexibility, and strong corrosion resistance. It can achieve heat conduction between the battery and the phase change material, and at the same time ensure that there is no chemical reaction outside the battery during operation. All the structures that need to be connected in the present invention are adhered by high-temperature glue. For example, the direct cooling plate 6 and the heat conductive frame 5 are adhered by high-temperature glue, and the heat conductive pad 4 and the side wall of the battery can also be adhered by high-temperature glue, which not only ensures the stable and compact structure, but also maximizes the optimal heat conduction capacity of each part.

[0046] In the prior art, generally only the heat dissipation problem of the battery pack 1 is considered, and the preciousness of heat in electric vehicles in winter is not noticed. However, the heat stored by the phase change of the composite phase change material 2 in the present invention in a low-temperature environment can delay the heat dissipation of the battery pack 1, and can also supply the heat stored by the phase change of the composite phase change material 2 in the low-temperature environment to the passenger compartment through the direct cooling plate 6, maximizing the battery health and the optimal utilization of energy.

[0047] In the cold stop process in winter of the present invention, the battery pack 1 is thermally insulated for a longer time by the solidification and heat release of the phase change material. When the heat in the passenger compartment is insufficient in winter, the direct cooling plate 6 absorbs the heat of the battery and the phase change material and supplies it to the passenger compartment to complete further energy saving. The thermal protection of each single battery of the battery pack 1 is completed by the way of wrapping with the phase change material and spacing with the heat conductive frame 5, and the process of thermal runaway of the battery is delayed as much as possible.

[0048] The present invention also provides a vehicle battery thermal management method, which includes the following steps:

[0049] Step 1, when the temperature sensor monitors that the temperature of the battery pack 1 exceeds the liquid phase limit temperature of the phase change material, the heat pump assembly is turned on for active direct cooling; the phase change material absorbs the radial heat of each battery of the battery pack 1, and transfers the heat to the direct cooling plate 6 through the heat conductive frame 5, and the direct cooling plate 6 absorbs the longitudinal heat of the battery pack 1; the heat pump assembly drives the refrigerant to circulate between the heat exchange channel 601 and the heat pump assembly, and dissipates heat at the direct cooling plate 6 through the phase change of the refrigerant, ensuring the temperature consistency of the battery pack 1 during the heat dissipation process.

[0050] Step 2, when the temperature sensor monitors that the temperature of the battery pack 1 is within the phase change temperature range of the phase change material, heat dissipation without energy consumption is achieved through the phase change material and the heat conductive frame 5;

[0051] Step 3: In a low-temperature environment, the direct cooling plate 6 preheats the battery pack 1 through the heat pump assembly. During the preheating process, the phase change material and the heat conduction frame 5 ensure the temperature consistency of the battery pack 1. In the winter parking condition, the heat stored in the phase change material can be provided to the battery pack 1 through phase change to achieve longer heat preservation. In addition, in winter, the direct cooling plate 6 can absorb the heat of the composite phase change material 2 and the battery pack 1 to the passenger compartment to achieve further energy conservation.

[0052] In the present invention, multiple batteries of the battery pack 1 are separated into multiple separated areas by the heat conduction frame 5, and each battery of the battery pack 1 is wrapped with a phase change material; in the high-temperature heat dissipation condition, the phase change material absorbs the radial heat of each battery in the battery pack 1 and transfers the heat in time through the heat conduction frame 5, so that the temperatures of the multiple batteries of the battery pack 1 are uniform. The direct cooling plate 6 is attached to one end of the battery pack 1 and can absorb the longitudinal heat of the battery pack 1. At the same time, the direct cooling plate 6 can also absorb the heat conducted by the heat conduction frame 5; then the direct cooling plate 6 ensures the heat dissipation efficiency to the greatest extent through the phase change of the refrigerant and ensures the consistency of the stable temperature of the battery pack 1 during the heat dissipation process. When the temperature is moderate and the battery temperature is within the phase change temperature range of the phase change material, the heat pump assembly can be not started, and only the heat exchange between the phase change material and the heat conduction frame and the battery pack is carried out to realize the cooling of the battery pack, and further the heat management of the battery pack without energy consumption can be realized.

[0053] In the present invention, specific examples are used to illustrate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A vehicle battery thermal management device, characterized in that: Comprising: A heat-conducting frame, in which there are a plurality of partition regions for placing the batteries of the battery pack, and a phase change material is filled in the gaps between the partition regions and the batteries. A direct cooling plate, connected to the bottom of the heat-conducting frame. An external heat exchange channel in the direct cooling plate is connected to a heat pump assembly, and a refrigerant can circulate between the heat exchange channel and the heat pump assembly.

2. The vehicle battery thermal management device according to claim 1, wherein: It further includes a heat-conducting pad, which is sleeved outside the batteries of the battery pack, and the inner side wall of the heat-conducting pad is attached to the side wall of the battery; the phase change material is filled between the inner side wall of the partition region and the outer side wall of the heat-conducting pad.

3. The vehicle battery thermal management device according to claim 2, characterized in that: The phase change material is a composite phase change material, which is made by mixing metal foam and paraffin.

4. The vehicle battery thermal management device according to claim 1, characterized in that: It further includes a battery management system, which includes a current sensor, a voltage sensor and a temperature sensor arranged on the battery pack, and the battery management system is used to monitor the working state of the battery.

5. The vehicle battery thermal management device according to claim 1, characterized in that: The heat-conducting frame includes a plurality of first partitions arranged in parallel. A plurality of second partitions penetrate through the plurality of first partitions. The plurality of second partitions are arranged in parallel, and the second partitions and the first partitions are arranged at an angle.

6. The vehicle battery thermal management device according to claim 1, wherein: The heat exchange channel in the direct cooling plate is arranged in a serpentine structure or a meandering structure.

7. The vehicle battery thermal management device according to claim 3, characterized in that: The phase change temperature of the composite phase change material is 35 - 40 °C.

8. The vehicle battery thermal management device according to claim 1, characterized in that: One end of the battery pack is attached to the outer surface of the direct cooling plate close to the heat-conducting frame.

9. A vehicle battery thermal management method, characterized in that: Including the following steps: Step 1, when the temperature sensor monitors that the temperature of the battery pack exceeds the liquid phase limit temperature of the phase change material, turn on the heat pump assembly for active direct cooling. Step 2, when the temperature sensor monitors that the temperature of the battery pack is within the phase change temperature range of the phase change material, achieve heat dissipation without energy consumption through the phase change material and the heat-conducting frame. Step 3, in a low-temperature environment, the direct cooling plate preheats the battery pack through the heat pump assembly. During the preheating process, heat is transferred through the phase change material and the heat-conducting frame to ensure the temperature consistency of the battery pack.

10. The vehicle battery thermal management method according to claim 9, characterized in that: In Step 1, the process of the heat pump assembly performing active direct cooling includes: The phase change material absorbs the radial heat of each battery of the battery pack, and transfers the heat to the direct cooling plate through the heat-conducting frame. The direct cooling plate absorbs the longitudinal heat of the battery pack; the heat pump assembly drives the refrigerant to circulate between the heat exchange channel and the heat pump assembly, and dissipates heat at the direct cooling plate through the phase change of the refrigerant to ensure the temperature consistency of the battery pack during the heat dissipation process.

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