Battery thermal management system with automatic hot spot detection function to achieve variable cooling rate

Abstract

The invention relates to a thermal management system for a battery module (100). The battery module comprises battery cells (102). The battery cells (102) associated with the battery module (100) are in thermal contact with one side of a thermally conductive plate (106), and a coolant (110) containing a ferromagnetic material (112) flows on the other side of the plate (106) in thermal contact with the plate (106). The system includes a winding coil (104) disposed within the battery module (100) at a predetermined position on a first side of a plate (106). When the battery cells heat, the coil (102) is configured to generate electromagnetic induction under the excitation of the direct current. The induction coil (102) on the first side of the plate (106) attracts the ferromagnetic material (112) of the coolant (110) toward the second side of the plate (106), thereby promoting heat transfer from the heating battery cell (102) to the plate (106) or the coolant (110).

Description

Background Art

[0002] Batteries are commonly used as energy storage devices in equipment and vehicles, providing power for electronic and electrical components related to the vehicles and equipment. Batteries, such as high-voltage (HV) batteries, also serve as the main propulsion source for electric vehicles and hybrid vehicles. A vehicle may include a battery pack, which includes one or more sets of battery modules. Each battery module may include one or more battery cells, and electrical interconnection is achieved between the battery cell terminals and the interconnection busbars.

[0003] Vehicles are typically equipped with a battery management system for controlling battery charging operations. In electric vehicles and hybrid vehicles, current research focuses on providing customers with a fast charging experience similar to refueling time by improving the battery charging time. This is generally achieved through a very high charging current / voltage. The increased power transfer generates thermal stress on the battery, leading to adverse consequences such as shortened battery life, degraded charging performance, and even thermal runaway in extreme cases.

[0004] Batteries generally have optimal charging performance within a narrow temperature range of 20°C to 45°C. However, during high-power fast charging, the battery temperature rises at a relatively high rate, so active battery thermal management is required. Additionally, since the battery cells within the battery degrade unevenly over time, hot spots may form, where the temperature of some battery cells / modules is higher than that of other parts. Therefore, from the perspectives of battery performance, efficiency, and service life, it is highly beneficial to provide an automated, improved, and efficient active battery thermal management solution that offers improved heat transfer capabilities, can detect hot spots, and provide more cooling for the hot spots.

[0005] Patent document US9786969B2 discloses a vehicle traction battery assembly, which includes a set of battery cells, a heat conducting plate in thermal communication with the set and defining a coolant path, and an electromagnet. The electromagnet is arranged as a solenoid valve assembly within the coolant path, selectively outputting a magnetic field to influence magnetic particles to aggregate and remain stationary in a specific pattern, so that one or more independent coolant sub-paths can be formed by the flow of coolant. The battery assembly also includes sensors, such as thermistors and thermometers, which are located near the battery and are designed to output signals indicating the temperature of the battery cells. The controller, based on the output signals from the sensors, is configured to direct the electromagnet to adjust the magnetic field based on the temperature of the battery cells, selectively outputting the magnetic field to restrict the flow of coolant through the independent coolant paths, thereby cooling the battery. Apparently, the cited reference document focuses on using an electromagnet as a valve assembly to create sub-cooling paths in the main cooling path to cool all battery cells along the sub-cooling paths, but in the case where the sensors detect an increase in the temperature of the battery cells, the sensors may be inefficient or even ineffective. However, the cited reference document does not detect hot spots within the battery and cannot provide cooling only to the hot spot areas of the battery. Therefore, the cited reference document does not provide a satisfactory solution to the above problems. Additionally, the use of sensors such as thermistors or thermometers and electromagnets makes the entire assembly complex and bulky.

[0006] Therefore, it is necessary to overcome the above-mentioned drawbacks, deficiencies and limitations associated with existing battery thermal management technologies, and to provide a simple, compact and efficient active battery pack thermal management system, which provides improved heat transfer capabilities and automatic hot spot detection functions to achieve an efficient variable cooling rate.

[0007] Objects of the Invention

[0008] The general object of the present disclosure is to overcome the problems associated with vehicle battery thermal management and existing thermal management technologies.

[0009] One object of the present disclosure is to provide a solution for active battery thermal management and cooling, which can provide improved heat transfer capabilities, detect hot spots and provide more cooling to the hot spot areas.

[0010] Another object of the present disclosure is to provide a simple, compact and efficient active battery thermal management system, which provides improved heat transfer capabilities and automatic hot spot detection functions to achieve an efficient variable cooling rate.

[0011] Another object of the present disclosure is to improve the lifespan and performance of the battery in an efficient and cost-effective manner.

[0012] Another object of the present disclosure is to provide a compact and efficient fast-charging battery pack, which has improved heat transfer capabilities and is capable of achieving automatic hot spot detection to provide an efficient variable cooling rate. Summary of the Invention

[0013] Aspects of the present disclosure relate to the technical field of battery thermal management systems. In particular, the present disclosure relates to a simple, compact, and efficient active battery thermal management system that provides improved heat transfer capabilities and automatic hot spot detection functionality to achieve an efficient variable cooling rate. Additionally, the present disclosure also relates to a compact and efficient battery pack that supports "battery" fast charging, which has improved heat transfer capabilities and is capable of performing automatic hot spot detection to provide an efficient variable cooling rate.

[0014] In one aspect, a thermal management system for a battery module is disclosed. The system includes a heat conducting plate having a first side and a second side. The one or more battery cells associated with the battery module are in thermal contact with the first side of the plate, and a coolant containing a ferromagnetic material is configured to be in thermal contact with and flow across the second side of the plate. The one or more coils are disposed on the first side of the plate at a predetermined position within the battery module. The predetermined position may include a gap space between one or more of the battery cells of the battery module. In the event that the one or more battery cells are heated, the one or more coils are configured to generate electromagnetic induction under direct current (DC) current excitation. Additionally, the one or more electromagnetic induction coils on the first side of the plate are adapted to attract the ferromagnetic material of the coolant to the second side of the plate, thereby facilitating heat transfer from the one or more heated battery cells to the coolant.

[0015] The system may include one or more negative temperature coefficient (NTC) resistors that are serially connected to the one or more coils such that each of the coils is serially connected to at least one NTC resistor. Additionally, one or more NTC resistors may also be in thermal contact with the one or more battery cells such that each battery cell is in thermal contact with at least one NTC resistor.

[0016] The resistance of the one or more NTC resistors may be selected / altered to provide variable cooling, which enables automatic enhanced cooling at hot spots in the following manner: when an increase in temperature of the one or more battery cells causes a decrease in resistance, the DC current supplied to the coils associated with the heated battery cells increases, prompting the ferromagnetic material of the coolant to be attracted to the one or more heated battery cells on the second side of the plate to cool the one or more heated battery cells.

[0017] In one aspect, the system may include a power source electrically connected to the one or more coils. The power source may be configured to supply a DC current having predetermined characteristics to the one or more coils. Additionally, the power source may be connected to the vehicle's battery management system and an electronic control unit.

[0018] The power supply can be configured to supply a pulsating direct current at a predetermined frequency to the one or more coils, so that the heated ferromagnetic material at the plate returns to the coolant flow, and further attracts the ferromagnetic material at a low temperature in the coolant to the plate.

[0019] In another aspect, a battery pack is disclosed. The battery pack includes one or more battery modules, and each battery module includes one or more battery cells. The battery pack further includes a heat conducting plate having a first side and a second side. The one or more battery cells associated with each battery module are in thermal contact with the first side of the plate, and a coolant containing ferromagnetic material is configured to be in thermal contact with and flow on the second side of the plate. Additionally, the battery pack includes one or more coils, which are disposed at a predetermined position within the battery pack on the first side of the plate. In the case where one or more battery cells are heated up, the one or more coils are configured to generate electromagnetic induction under the excitation of a direct current. The electromagnetic induction coil on the first side of the plate is adapted to attract the ferromagnetic material of the coolant towards the second side of the plate, thereby facilitating the transfer of heat from the one or more heated battery cells to the coolant.

[0020] The predetermined position may include the gap space between the one or more battery cells, the gap space between the one or more modules, or a combination thereof.

[0021] The battery pack may include one or more negative temperature coefficient (NTC) resistors, which are connected in series with the one or more coils of each of the battery modules, ensuring that each coil is connected in series with at least one NTC resistor. The one or more NTC resistors may be in thermal contact with the one or more battery cells of each battery module, ensuring that each battery cell is in thermal contact with at least one NTC resistor. The resistance of the one or more NTC resistors may be selected to provide variable cooling. When the increase in temperature of one or more battery cells causes the resistance to decrease, the direct current supplied to the coil associated with the heated battery cell increases, thereby achieving automatic enhanced cooling at the hot spot.

[0022] The battery pack may include a power supply electrically connected to the one or more coils. The power supply can be configured to supply a pulsating direct current to the one or more coils, so that the heated ferromagnetic material returns to the coolant flow, and further attracts the ferromagnetic material at a low temperature in the coolant to the plate.

[0023] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of the preferred embodiments in conjunction with the accompanying drawings, in which like reference numerals represent like components. Brief Description of the Drawings

[0024] The drawings are intended to provide a further understanding of the present disclosure and are incorporated into the specification and form a part thereof. The drawings illustrate exemplary embodiments of the present disclosure and, together with the specification, are used to explain the principles of the present disclosure.

[0025] Figures 1A to 1B An exemplary diagram showing the application of the thermal management system of the present disclosure to a battery module according to an embodiment of the present disclosure. The battery module includes a plurality of battery cells.

[0026] Figure 2A and 2B An exemplary side view of the system of the present disclosure in a battery module to illustrate the working principle of the present invention. One side of the heat conducting plate has a coil, and the other side has a coolant flow with a ferromagnetic body.

[0027] Figure 3 An exemplary circuit diagram of the system of the present disclosure according to an embodiment of the present disclosure.

[0028] Figure 4 An exemplary schematic diagram showing the application of the thermal management system of the present disclosure to a battery pack according to an embodiment of the present disclosure. The battery pack includes Figure 1A and 1B a plurality of battery modules. Detailed Embodiments

[0029] The following is a detailed description of the embodiments of the present disclosure shown in the drawings. The embodiments clearly convey the content of the present disclosure in sufficient detail. However, the degree of detail provided is not intended to limit the expected variations of the embodiments; on the contrary, it is intended to cover all modifications, equivalents, and alternative forms that fall within the spirit and scope of the present disclosure as defined by the appended claims.

[0030] The embodiments of the present disclosure relate to a simple, compact, and efficient battery active thermal management system, which provides improved heat transfer capacity and automatic hot spot detection function to achieve an efficient variable cooling rate. The embodiments of the present disclosure also relate to a compact and efficient fast-charging battery pack, which has improved heat transfer capacity and is capable of automatic hot spot detection to provide an efficient variable cooling rate.

[0031] Referring to Figures 1A to 4 , the present disclosure discloses a thermal management system (hereinafter referred to as: system) for a battery module 100 and a battery pack 400. The battery pack 400 may include one or more battery modules 100-A to 100-F (collectively referred to as battery modules 100 herein, and individually also referred to as battery module 100), as Figure 4 shown. In addition, each battery module 100 may include one or more battery cells 102 (collectively referred to as battery cells 102 herein, and individually also referred to as battery cell 102), as Figure 1A and 1B shown.

[0032] The system may include one or more coils 104 (collectively referred to herein as coils 104, and individually also referred to as coil 104). The coils may be micro-wound coils 104 having a predetermined number of turns. Thus, by exciting the coil 104 with a DC power supply 302 or a DC current, the coil 104 can be transformed into an electromagnet. In addition, the system or the battery module 100 / battery pack 400 may include a heat conducting plate 106 (hereinafter referred to as: plate 106) having a first side and a second side. The battery module 100 or the battery cells 102 associated with the battery module 100 may be positioned in thermal contact with the first side of the plate 106. Additionally, the coil 104 may also be positioned on the first side of the plate 106 near the battery cell 102 (i.e., on one side of the battery cell 102).

[0033] In addition, the system or the battery module 100 / battery pack 400 may include a coolant 110 containing a ferromagnetic material 112, and the coolant is configured to flow in thermal contact with the second side of the plate 106. In one embodiment, the second side of the plate 106 may be provided with channels 114, and the coolant 110 may be circulated through the channels 114 by a pump so that the flowing coolant 110 can maintain thermal contact with the second side of the plate 106. In one example, iron / Glycol or other ferromagnetic materials 112 (nanoparticles or microparticles of ferromagnetic materials) may be suspended in the coolant 110.

[0034] The system may include one or more negative temperature coefficient (NTC) resistors (collectively referred to herein as NTC resistors 108, and individually also referred to as NTC resistor 108), as Figure 1B and 3 shown, the resistor is in series with the one or more coils 104 to ensure that each coil 104 is at least in series with one NTC resistor 108. The one or more NTC resistors 108 may be positioned in thermal contact with the battery cell 102 to ensure that each battery cell 102 is at least in thermal contact with one NTC resistor 108. In one embodiment, the network formed by the coil 104 and the NTC resistor 108 may be placed and encapsulated in the gap space between the battery cells 102 and between the battery modules 100 within the battery pack 400, but is not limited to this case. In one example, the NTC resistor 108 may be positioned on one side of the battery cell 102, as Figure 1B shown.

[0035] In one embodiment, in the case where one or more battery cells 102 generate heat, the coil 104 is configured to generate electromagnetic induction under the excitation of a DC current or a DC power supply 302. Thus, one or more electromagnetic induction coils 104 on the first side of the plate 106 can act as electromagnets to attract the ferromagnetic material 112 of the coolant 110 towards the second side of the plate 106, causing the ferromagnetic material 112 to adhere to the second side of the plate 106, asFigure 2A and 2B as shown. This promotes and enhances the heat exchange between the heated battery cell 102 of the battery module 100 and the plate 106 or the coolant 110. The thermal conductivity between the heated battery cell 102 and the coolant 110 is now significantly increased because the plate 106 not only exchanges heat directly with the coolant 110 flow but also with the attached ferromagnetic material. Therefore, the battery cell 102 can now transfer more heat to the plate 106.

[0036] The NTC resistor 108 is selected to provide variable cooling to achieve automatic enhanced cooling at the hot spot (heated battery cell 102) as follows: When the temperature rise causes the resistance of the NTC resistor 108 to decrease, the direct current supplied to the coil 104 associated with the heated battery cell 102 increases, prompting the ferromagnetic material 112 of the coolant 110 to be attracted towards one or more heated battery cells 102 on the second side of the plate 106 to cool one or more heated battery cells 102. The NTC resistor 108 has a negative temperature coefficient, so when any battery cell 102 (at the hot spot within the battery module 100) generates heat and causes the NTC resistor 108 to heat up, the resistance of the NTC resistor 108 in thermal contact with the heated battery cell 102 decreases. The decrease in the resistance of the NTC resistor 108 at the hot spot only increases the direct current supplied to the coil 104 at the hot spot without affecting the remaining coils 104. This prompts the ferromagnetic material 112 suspended in the coolant 110 to be mostly attracted to the heated battery cell 102 (hot spot) to cool the heated battery cell 102 at the hot spot.

[0037] The automatic detection of the hot spot and the implementation of variable cooling are accomplished as follows: The resistance value of the NTC resistor 108 varies with the heat generated by different battery cells 102. For example, the more heat the battery cell 102 generates, the smaller the resistance of the NTC resistor 108. Additionally, the smaller the resistance of the NTC resistor 108, the greater the current flowing into the coil 104 associated with the corresponding battery cell 102 and NTC resistor 108. Therefore, the current and magnetic field intensity generated by different coils 104 can be automatically adjusted such that the hottest battery cell 102 obtains the maximum magnetic field intensity, thereby achieving the maximum degree of cooling, and vice versa. For example, as Figure 2B shown, since the battery cell 102 associated with the coil 104-2 heats up more, the ferromagnetic material 112 of the coolant 110 is attracted more strongly to the plate 106 in the hot spot area (near the coil 104-2) generated by the heated battery cell 102 than to other battery cells 102 (near the coils 104-1 and 104-2).

[0038] See Figure 3, in one embodiment, the system or battery module 100 / battery pack 400 may include a power source 302, which is electrically connected to one or more coils 104 through an NTC resistor 108 in series with each coil 104. The power source 302 may also be operatively coupled to the battery management system (BMS) 304 and / or the electronic control unit (ECU) 306 of the vehicle on which the battery pack 400 is mounted. The power source 302 is configurable to supply a direct current having predetermined characteristics to one or more coils 104. In one embodiment, the power source 302 is configurable to supply a pulsating direct current of a predetermined frequency (preferably a low frequency or an extremely low frequency) to the one or more coils 104. This causes the ferromagnetic material 112 on the second side of the plate 106 that is magnetically attracted and heated to return to the flowing coolant 110, and also causes the ferromagnetic material 112 with a lower temperature in the coolant 110 to be attracted to the plate 106 for further heat exchange. The size and number of turns of the coil 104 can be selected to generate a magnetic field strength sufficient to pull the weight of the ferromagnetic material nanoparticles / microparticles suspended in the coolant 110.

[0039] Accordingly, the present disclosure overcomes the disadvantages, deficiencies, and limitations associated with battery module heating and existing battery thermal management systems, and provides a simple, compact, and efficient active battery thermal management system for this purpose, which provides improved heat transfer capabilities and an automatic hot spot detection function to achieve an efficient variable cooling rate. In addition, the present disclosure also provides a compact and efficient fast-charging battery pack, which has improved heat transfer capabilities and can achieve automatic hot spot detection to provide an efficient variable cooling rate. This supports fast charging, extends battery life, and improves the state of health, improves charging performance, and eliminates thermal problems such as battery thermal runaway or overheating.

[0040] Although the above describes various embodiments of the present invention, other or further embodiments of the present invention can be conceived without departing from its basic scope. The scope of the invention is determined by the appended claims. The present invention is not limited to the described embodiments, versions, or examples, which are intended to enable those of ordinary skill in the art to practice and use the present invention in combination with the information and knowledge available to those of ordinary skill in the art.

[0041] Advantages of the Invention

[0042] The present invention overcomes the problems associated with vehicle battery thermal management and existing thermal management technologies.

[0043] The present invention provides a solution for active battery thermal management and cooling, which can provide improved heat transfer capabilities, detect hot spots, and provide more cooling for hot spots.

[0044] The present invention provides a simple, compact, and efficient active battery thermal management system, which provides improved heat transfer capabilities and an automatic hot spot detection function to achieve an efficient variable cooling rate.

[0045] The present invention improves the service life and performance of a battery in an efficient and cost-effective manner.

[0046] The present invention provides a compact, efficient and fast-charging support battery pack, which has improved heat transfer ability and can achieve automatic hot spot detection to provide an efficient variable cooling rate.

Claims

1. A thermal management system for a battery module (100), the system comprising: A heat conducting plate (106) having a first side and a second side, wherein one or more battery cells (102) associated with the battery module (100) are in thermal contact with the first side of the plate (106), and a coolant (110) containing a ferromagnetic material (112) is configured to flow in thermal contact with the second side of the plate (106); and One or more coils (104) disposed at a predetermined position on the first side of the plate (106) within the battery module (100), wherein when the one or more battery cells (102) generate heat, the one or more coils (104) are configured to generate electromagnetic induction under direct current excitation; Wherein the one or more electromagnetic induction coils (104) on the first side of the plate (106) are adapted to attract the ferromagnetic material (112) of the coolant (110) towards the second side of the plate (106), thereby promoting heat transfer from the heated one or more battery cells (102) to the coolant (110).

2. The system according to claim 1, wherein The system includes one or more negative temperature coefficient (NTC) resistors (108), the NTC resistors being connected in series with the one or more coils (104) such that each of the coils (104) is connected in series with at least one NTC resistor (108), and Wherein the one or more NTC resistors (108) are in thermal contact with the one or more battery cells (102) such that each of the battery cells (102) is in thermal contact with at least one NTC resistor (108).

3. The system according to claim 2, wherein, The resistance of the one or more NTC resistors (108) is selected to provide variable cooling in the following manner to achieve higher automatic cooling at hot spots: the resistance decreases due to heating, such that the direct current supplied to the coils (104) associated with the heated one or more battery cells (102) increases, thereby causing the ferromagnetic material (112) of the coolant (110) to be attracted towards the heated one or more battery cells (102) on the second side of the plate (106) to cool the heated one or more battery cells (102).

4. The system according to claim 2, wherein The system includes a power supply (302) electrically connected to the one or more coils (104), wherein the power supply (302) is configured to supply direct current having predetermined characteristics to the one or more coils (104).

5. The system according to claim 4, wherein, The power supply (302) is configured to supply pulsating direct current of a predetermined frequency to the one or more coils (104) to return the heated ferromagnetic material (112) at the plate (106) to the flowing coolant (110), and further to attract the low-temperature ferromagnetic material (112) from the coolant (110) towards the plate (106).

6. The system according to claim 1, wherein, The predetermined position includes the gap space between the one or more battery cells (102) of the battery module (100).

7. A battery pack (400), comprising: One or more battery modules (100), each of the battery modules including one or more battery cells (102); A heat conducting plate (106) having a first side and a second side, wherein one or more battery cells (102) associated with each battery module (100) are in thermal contact with the first side of the plate (106), and a coolant (110) containing a ferromagnetic material (112) is configured to flow in thermal contact with the second side of the plate (106); and One or more coils (104) disposed at a predetermined position on the first side of the plate (106) within the battery pack (400), wherein when the one or more battery cells (102) generate heat, the one or more coils (104) are configured to generate electromagnetic induction under the excitation of a direct current; Wherein the electromagnetic induction coil (104) on the first side of the plate (106) is adapted to attract the ferromagnetic material (112) of the coolant (110) towards the second side of the plate (106), thereby promoting heat transfer from the heated one or more battery cells (102) to the coolant (110).

8. The battery pack (400) according to claim 7, wherein, The battery pack (400) includes one or more negative temperature coefficient (NTC) resistors (108), the NTC resistors being connected in series with the one or more coils (104) of each battery module (100) such that each coil (104) is connected in series with at least one NTC resistor (108), and Wherein the one or more NTC resistors (108) are in thermal contact with the one or more battery cells (102) of each battery module (100) such that each battery cell (102) is in thermal contact with at least one NTC resistor; and Wherein the resistance of the one or more NTC resistors (108) is selected to increase the direct current fed into the coil (104) associated with the heated one or more battery cells (102) by reducing the resistance due to heating, thereby providing variable cooling to achieve higher automatic cooling at hot spots.

9. The battery pack (400) according to claim 8, wherein, The battery pack (400) includes a power source (302) electrically connected to the one or more coils (104), wherein the power source is configured to supply a pulsating direct current to the one or more coils (104) to return the heated ferromagnetic material (112) to the flowing coolant (110), and further to attract the low-temperature ferromagnetic material (112) from the coolant (110) towards the plate (106).

10. The battery pack (400) according to claim 8, wherein, The predetermined position includes: a gap space between the one or more battery cells (102), a gap space between the one or more modules, or a combination thereof.

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