Battery system for thermal management of battery cells

Abstract

The disclosed technology generally relates to a battery system, and more particularly to a battery system for thermal management of battery cells. From one aspect, the battery system includes a plurality of battery cells electrically coupled to each other, a plurality of switches each coupled to one of the plurality of battery cells, one or more heaters electrically coupled to the plurality of switches to dissipate power from the plurality of battery cells, and one or more thermal conduits to transmit heat generated by the one or more heaters to at least one of the battery cells.

Description

[Technical Field]

[0001] The disclosed technology relates generally to battery systems, and more particularly to battery systems for thermal management of battery cells. [Background technology]

[0002] Due to the increasing global warming caused by global economic growth, there is an urgent need for renewable and sustainable energy systems based on renewable energy sources (e.g., solar and wind energy). To improve grid network stability in the face of fluctuations due to the intermittent availability of such energy, the development of energy storage systems (ESS) has enabled the storage of excess electricity, which can then be transferred to end users or the power grid when needed. Alternatively, electrochemical-based ESS (e.g., rechargeable or secondary batteries) can provide a cost-effective and clean form of energy storage solution. Examples of electrochemical energy storage systems include lithium-ion, lead-acid, sodium-sulfur, and redox-flow batteries. Different storage times are required for different applications, such as short-term, medium-term, and long-term storage. Different types of electrochemical energy storage systems have different physical and / or chemical properties. Some of the factors that determine the suitability of the electrochemical energy storage system for a particular application include investment cost, power, energy, lifespan, recyclability, efficiency, scalability, and maintenance costs. Competitive factors are considered when selecting and designing an appropriate electrochemical storage system. Summary of the Invention [Means for solving the problem]

[0003] From a first aspect, a battery system includes a plurality of battery cells electrically coupled to one another. The battery system further includes a plurality of switches each coupled to one of the plurality of battery cells. The battery system further includes one or more heaters electrically coupled to the switches and configured to dissipate power from the plurality of battery cells. The battery system further includes one or more thermal conduits configured to transmit heat generated by the one or more heaters to at least one of the plurality of battery cells.

[0004] From a second aspect, a battery system includes a plurality of battery cells electrically coupled to each other. The battery system further includes a plurality of switches, each coupled to one of the plurality of battery cells. The battery system further includes one or more heaters electrically coupled to the plurality of switches and configured to generate heat when activating one or more switches by dissipating power from the plurality of battery cells. The one or more heaters actively or passively balance the state of charge (SoC) of the battery cells and act as one or more resistors to thermally increase the temperature of the battery cells.

[0005]

[0010] From a third aspect, a thermal management method for a battery system includes sensing a state of charge (SoC) of each of a plurality of battery cells electrically coupled to one another. The method further includes activating one or more switches coupled to the plurality of battery cells to dissipate power from one or more battery cells having an SoC above a predetermined critical value via one or more heaters to generate heat. The method further includes transmitting heat generated from the one or more heaters to at least one of the plurality of battery cells via one or more thermal conduits. The battery system may be according to one or both of the first and second aspects.

[0006] According to a fourth aspect, an energy storage system (ESS) includes a battery system including a plurality of battery cells electrically coupled to each other, a plurality of switches each coupled to one of the plurality of battery cells, and one or more resistors electrically coupled to the plurality of battery cells for actively or passively balancing the states of charge (SoC) of the battery cells. The ESS further includes a power control system (PCS) electrically coupled to the battery system. The ESS further includes an electrical load electrically coupled to the PCS. One or both of the PCS and the electrical load are electrically coupled to a grid. Furthermore, the one or more battery systems, the PCS, and the electrical load are insulated from each other by an insulating material. The battery system may be according to one or both of the first and second aspects.

[0007] According to a fifth aspect, an energy storage system (ESS) includes a battery system including a plurality of battery cells electrically coupled to each other, a plurality of switches each coupled to one of the plurality of battery cells, and one or more resistors electrically coupled to the switches for actively or passively balancing the states of charge (SoC) of the battery cells. The ESS further includes a power control system (PCS) electrically coupled to the battery system. The ESS further includes an electrical load electrically coupled to the power control unit. One or both of the PCS and the electrical load are thermally coupled to the battery system by one or more thermal conduits that transmit heat generated by one or both of the PCS and the electrical load to at least one of the battery cells. The battery system may be according to one or both of the first and second aspects. [Brief explanation of the drawings]

[0008] [Figure 1A] 1A and 1B are schematic diagrams illustrating exemplary states of charge of an unmanaged battery cell. [Figure 1B] 1A and 1B are schematic diagrams illustrating exemplary charge states of a management battery cell. [Figure 2A] FIG. 1 is a diagram illustrating an example of an active balancing method for battery cells. [Figure 2B] FIG. 1 is a diagram illustrating an example of a passive balancing method for battery cells. [Figure 3A] FIG. 1 is a diagram illustrating a schematic of an exemplary battery system including a plurality of battery cells electrically coupled to the battery system. [Figure 3B] FIG. 1 illustrates an exemplary battery management system implemented on a common substrate. [Figure 4A] FIG. 1 is a diagram illustrating an exemplary energy storage system configured for a battery system according to an embodiment. [Figure 4B] FIG. 10 is a schematic diagram of another exemplary energy storage system configured for a battery system, according to an embodiment. [Figure 5A] FIG. 1 illustrates a schematic diagram of an exemplary battery system configured for thermal management of battery cells in accordance with various embodiments. [Figure 5B] FIG. 1 illustrates a schematic diagram of an exemplary battery system configured for thermal management of battery cells in accordance with various embodiments. [Figure 5C] FIG. 1 illustrates a schematic diagram of an exemplary battery system configured for thermal management of battery cells in accordance with various embodiments. [Figure 5D] FIG. 1 illustrates a schematic diagram of an exemplary battery system configured for thermal management of battery cells in accordance with various embodiments. [Figure 5E] FIG. 1 illustrates a schematic diagram of an exemplary battery system configured for thermal management of battery cells in accordance with various embodiments. [Figure 6A] FIG. 2 is a flow chart illustrating a method for thermal management of a battery system according to an embodiment of the present invention. [Figure 6B] FIG. 2 is a flow chart illustrating a method for thermal management of a battery system according to an embodiment of the present invention. [Figure 7A] FIG. 1 illustrates a schematic diagram of an energy storage system configured for thermal management of battery cells in accordance with various embodiments. [Figure 7B]FIG. 1 illustrates a schematic diagram of a battery system configured for thermal management of battery cells according to some embodiments. [Figure 7C] FIG. 10 is a schematic diagram illustrating a battery system configured for thermal management of battery cells according to some other embodiments. [Figure 7D] FIG. 1 illustrates a schematic diagram of an energy storage system configured for thermal management of battery cells in accordance with various embodiments. [Figure 8A] 1 is a schematic diagram of a redox battery cell that may be embodied as part of a battery and energy storage system according to an embodiment; [Figure 8B] 1 is a schematic diagram of a redox battery cell that may be embodied as part of a battery and energy storage system according to an embodiment; [Figure 8C] 1 is a schematic diagram of a redox battery cell that may be embodied as part of a battery and energy storage system according to an embodiment; [Figure 8D] 1 is a schematic diagram of a redox battery cell that may be embodied as part of a battery and energy storage system according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0009] These and other objects and advantages will become apparent from the description herein. In the following detailed description, reference is made to the accompanying drawings, which form a part of this specification, and in which specific embodiments are shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it will be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the disclosed embodiments. Accordingly, the accompanying drawings are set forth merely to illustrate exemplary embodiments of the disclosed embodiments. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the disclosed embodiments is defined by the appended claims.

[0010] In consideration of the above, one objective of one or more aspects of some embodiments is to provide a thermal management method and a battery system that improves the efficiency of electrochemical energy storage. A battery management system (BMS) refers to a control system electrically coupled to a battery pack including a plurality of battery cells to supervise the battery pack, including battery monitoring, providing battery protection, estimating battery operating conditions, continuously optimizing battery performance, and communicating the operating conditions with an external device.

[0011] In some embodiments, a battery system includes a battery pack and a battery management system (BMS) coupled thereto, the function of which includes balancing multiple battery cells, which may be electrically coupled in series and / or parallel within the battery pack, such that the battery cells within the battery pack are similar or, in effect, reach the same state of charge (SoC).

[0012] In view of the fact that chemical reactions can accelerate at elevated temperatures and cause the battery management system to generate heat during operation, in some other embodiments, the heat generated by the battery management system is recovered and efficiently transferred to the battery cells to increase their temperature.

[0013] In view of the fact that high temperatures accelerate chemical reactions and battery management systems can generate heat during operation, in the embodiments disclosed herein, the heat generated by the battery management system is recovered and efficiently transferred to the battery cells to raise their temperature.

[0014] 1a and 1b schematically illustrate exemplary charge states of unmanaged and managed battery cells, respectively. Without a BMS, various processes can accelerate damage to degraded battery cells. For example, during charging, the degraded battery cells may reach their charge limit prematurely due to a decrease in their capacity. The entire battery pack may continue to charge even after the degraded battery cells have reached their charge limit. This overcharging can further exacerbate the damage caused by overcharging of the already degraded battery cells, accelerating battery pack failure. Similarly, during discharging, degraded battery cells may reach their discharge limit prematurely due to their reduced capacity. The battery pack as a whole may continue to discharge even after the degraded battery cells have reached their discharge limit. This overdischarge can further damage the already degraded battery cells. Therefore, a BMS is needed to balance the battery cells.

[0015] Some balancing methods are dissipative, where energy is removed from the most charged cell and lost as heat. Other balancing methods are non-dissipative, where energy is transferred between different cells, significantly reducing the energy lost as heat. Dissipative balancing methods are also called passive balancing methods, and non-dissipative balancing methods are also called active balancing methods.

[0016] 2a and 2b schematically illustrate exemplary methods for active and passive balancing of battery cells, respectively. However, for illustrative purposes, FIG. 2a illustrates active balancing between two battery cells 12A-1 and 12A-2. Similarly, FIG. 2b illustrates passive balancing between two battery cells 12B-1 and 12B-2. Passive and active cell balancing monitors the battery cells of a battery stack to maintain a robust battery state of charge (SoC). This extends battery life and, as previously discussed, prevents battery cell damage that can occur due to overcharging and / or over-discharging. Referring to FIG. 2b, passive balancing results in battery cells 12B-1 and 12B-2 having similar or even identical SoCs by simply dissipating excess charge through bleed resistors. However, this does not extend the run time of the system. Referring to FIG. 2a, active cell balancing is a more complex balancing technique that redistributes charge between battery cells 12A-1, 12A-2 during charge / discharge cycles, increasing the total charge available in the battery pack, increasing system run time, reducing charging time compared to passive balancing, and reducing heat generated during balancing.

[0017] Passive balancing has some obvious disadvantages. For example, the wasted energy can be harmful to the environment. Also, the heat generated by high balancing currents can be detrimental to battery cells. On the other hand, passive balancing has the advantage of being simple and low cost. Active balancing, while having the obvious advantage of not wasting much energy, can also have disadvantages. For example, because more electrical components are used, active balancing can be disadvantaged by higher cost, lower reliability, and / or larger volume. Also, the standby current generated by active balancing can result in greater power loss than passive balancing.

[0018] Some battery cells lose capacity at low temperatures due to the relatively slow chemical reaction rates that govern charge and discharge. For example, charging lithium-ion battery cells below approximately 0°C (32°F) can be problematic because metallic lithium plating can occur on the positive electrode during charging at sub-zero temperatures. Plating can permanently damage the battery cell, resulting in a loss of capacity and potentially weakening it to failure if the battery cell is exposed to vibration or other stress conditions. On the other hand, lithium-ion battery cells can experience performance loss when operated at temperatures much higher than room temperature (e.g., above approximately 30°C). If lithium-ion battery cells are continuously charged and recharged above this temperature, the performance loss can increase significantly (e.g., up to 50%). Continuous exposure to excessive heat, especially during rapid charge and discharge cycles, can prematurely age and reduce battery life. For these reasons, a BMS capable of controlling the temperature of the battery pack by heating and cooling the battery cells is needed.

[0019] FIG. 3a schematically illustrates an exemplary battery system 10 including a plurality of battery cells 12-1,..., 12-(n-2), 12-(n-1), 12-n electrically coupled to a battery management system (BMS) 14. The BMS 14 may, depending on the embodiment, serve as a basic BMS capable of implementing various thermal management features and methods described herein. The illustrated BMS 14 may be a passive or active BMS 14. The plurality of battery cells 12-1,..., 12-(n-2), 12-(n-1), 12-n (hereinafter commonly referred to as battery cells 12) are electrically coupled to one another in series and / or parallel. The battery system 10 further includes a plurality of switches 16-1,..., 16-(n-2), 16-(n-1), 16-n (hereinafter commonly referred to as switches 16) each coupled to a corresponding battery cell 12. The battery system 10 further includes one or more resistors 18-1,...,18-(n-2), 18-(n-1), 18-n (hereinafter referred to as resistors 18) electrically coupled to the switches 16 to dissipate power from the battery cells when one or more of the switches 16 are activated. The battery system 10 further includes a controller 26 that senses the state of charge (SoC) of the battery cells 12 and selectively activates one or more of the switches 16 based on the SoC. For example, when the controller 26 senses that the SoC of one or more of the battery cells 12 is higher than a critical value after charging for a predetermined period of time, for example, by measuring the voltage of the battery cell, the controller 26 can activate each of the switches 16 coupled to one or more of the battery cells 12 and selectively dissipate excess charge from the battery cells using the associated respective resistors 18. The controller 26 can remove excess charge from one or more of the battery cells 12 until the one or more battery cells 12 have similar or actually the same SoC, as shown in FIG. 1b, for example.

[0020] Figure 3b shows an exemplary battery management system 20 implemented on a common substrate. Battery management system 20 may represent a physical implementation of BMS 14 shown in Figure 3a. Resistors 18, switches 16, and controller 26 are integrated onto a common circuit board 22. Circuit board 22 includes terminals 24 for electrically coupling to multiple battery cells.

[0021] FIG. 4a schematically illustrates an exemplary energy storage system (ESS) 30 configured for the battery system 10 (FIG. 3a), according to an embodiment. The illustrated ESS 30 can serve as a base ESS including the battery system 10, including the BMS 14 (FIG. 3a), according to an embodiment. The ESS 30 further includes a power control system (PCS) 32 electrically coupled to a grid 34. The PCS 32 is centrally electrically coupled to the battery system 10 and an electrical load 36. The PCS 32 is configured to receive power, e.g., AC power, from the grid 34 and control the power, e.g., DC power, it transfers to the battery system 10 and the electrical load 36. The PCS 32 is further configured to control the transfer of power from the battery system 10 to the load 36. When configured in this manner, the PCS 32 is configured to control the transfer of power between the battery system 10 and the grid 34, between the load 36 and the grid 34, and between the battery system 10 and the load 36.

[0022] FIG. 4b schematically illustrates another exemplary energy storage system (ESS) 30 configured for the battery system 10 (FIG. 3a), according to an embodiment. The exemplary ESS 30 can serve as a base ESS including the battery system 10, including the BMS 14 (FIG. 3a), according to an embodiment. The ESS 30 includes a power control system (PCS) 32 electrically coupled to a grid 34. Similar to the ESS 30 illustrated in FIG. 4a, in the illustrated ESS 30, the PCS 32 is electrically coupled to the battery system 10 and a load 36. The PCS 32 is configured to receive power, e.g., AC power, from the grid 34 and control the power, e.g., DC power, delivered to the battery system 10 and the load 36. However, unlike the ESS 30 illustrated in FIG. 4a, both the PCS 32 and the electrical load 36 are coupled to the grid.

[0023] Battery system for thermal management of battery cells As described above, a battery management system (BMS) can be used to control the temperature of battery cells through heating and / or cooling. For heating, some battery systems can use an active heater to heat the battery cells. The active heater can be powered by an external power source, such as an AC power source, or an internal power source, such as the battery pack of the battery system. For example, a thermal hydraulic system, including an electric heater that heats a fluid that is pumped and dispersed throughout the battery pack, can be used as an active heater. Other battery systems can recover externally generated heat that would otherwise be wasted. For example, some electric vehicles can be configured to recover heat generated by a motor, which acts as a load, to heat the battery cells. In such battery systems, a BMS can be used to manage the heat transfer from a heat source to the battery cells. However, existing heating techniques involve additional energy consumption and / or result in heat that is not controlled by the battery system. Therefore, there is a need to provide a system and method that can efficiently provide heat that can be controlled using a BMS provided from the battery cells themselves to the battery cells.

[0024] To address at least these needs, the present application discloses a battery system including a plurality of battery cells electrically coupled to one another. The battery system includes a plurality of switches, each coupled to one of the battery cells. The battery system further includes one or more heaters electrically coupled to the switches and configured to generate heat when activating one or more switches by dissipating power from the battery cells. The battery system further includes one or more thermal conduits configured to transmit heat generated by the one or more heaters to at least one battery cell to raise its temperature.

[0025] 5a-5e schematically illustrate example battery systems 10 configured for thermal management of battery cells 12 in accordance with various embodiments. Each of the illustrated example battery systems 10 includes a plurality of battery cells 12-1,...,12-(n-2), 12-(n-1), 12-n (hereinafter commonly referred to as battery cells 12) and a battery management system (BMS) 14. The plurality of battery cells 12 are electrically coupled to one another in series and / or parallel. The battery systems 10 further include a plurality of switches 16-1,...,16-(n-2), 16-(n-1), 16-n (hereinafter commonly referred to as switches 16) each coupled to one of the battery cells 12. The battery systems 10 further include one or more heaters 17-1,...,17-(n-2), 17-(n-1), 17-n (hereinafter commonly referred to as heaters 17) electrically coupled to the switches 16 to act as an effective heat source. The battery system 10 may further include a controller 26 that senses a state of charge (SoC) of the battery cells 12 and selectively activates one or more switches 16 based on the SoC. The heater 17 is electrically coupled to the switches 16 and generates heat when it dissipates power from the battery cells 12 to activate the associated one or more switches 16. The heater 17 may include one or more of a common resistor, copper wire, nichrome wire, an SMD resistor (surface mount resistor or chip resistor), an electric boiler, and a heat pump.

[0026] To efficiently transfer heat, the battery system further includes one or more thermal conduits 19-1,...,19-(n-2), 19-(n-1), 19-n (hereinafter referred to as thermal conduits 19) that transfer heat generated by the one or more heaters 17 to at least one of the battery cells 12, thereby increasing the temperature of one or both of the resistors 18 and the thermal conduits 19 by at least 2°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, or any of these values ​​within a range defined by the same battery system arrangement. In addition to providing heat to the battery cells 12, at least the switches 16 and the heaters 17 may be part of the BMS 14 configured to actively or passively balance the battery cells 12. The controller 26 may be configured to sense the state of charge (SoC) of the battery cells 12 and selectively activate one or more switches 16 based on the SoC, for example, when the sensed SoC falls outside a predetermined range. The sensed SoC may be proportional to the battery capacity and may be different for different ones of the battery cells 12 .

[0027] For example, if the controller 26 detects that the SoC of one or more of the battery cells 12 is above a critical value after charging for a certain period of time, such as by measuring the voltage of the battery cells 12, the controller 26 may activate a respective one of the switches 16 coupled to one or more batteries 12 to selectively dissipate excess charge from the batteries using a respective heater 17 coupled to each of the batteries. The controller 26 may release excess charge from one or more battery cells 12 until the one or more battery cells 12 have similar or actually the same SoC. Thus, the heater 17 not only heats the battery cells 12 but also performs the dual function of cell balancing.

[0028] According to various embodiments, the controller 26 activates one or more switches 16 when it determines that the temperature of the at least one battery cell 12 is lower than a pre-set temperature. In some embodiments, the controller 26 activates the one or more switches 16 after cooling the at least one battery cell 12 to a temperature lower than the pre-set temperature. The pre-set temperature may be, for example, approximately 15°C, 17°C, 19°C, 21°C, 23°C, 25°C, or a value within a range defined by any of these values, e.g., approximately 20°C. The controller 26 may be further configured to deactivate the activated one or more switches 16 when it senses that the temperature of the at least one battery cell 12 has increased by at least approximately 2°C, 4°C, 6°C, 8°C, 10°C, or a value within a range defined by any of these values, e.g., approximately 5°C.

[0029] According to various embodiments, the heat generated by the one or more heaters 17 may cause the temperature of at least one of the battery cells 12 to reach a temperature within a range defined by 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, or any of these values, depending on the application of the battery system 10 and the type of battery cell 12. For example, when integrated as part of the ESS 30, the battery cell 12 may be heated to within a range of approximately 20-30°C. If the battery cell 12 is a redox battery cell, e.g., a vanadium-ion battery cell, the battery cell 12 may be heated to within a range of 15-40°C.

[0030] One or more heaters 17 can simultaneously act as an effective heat source as well as cell balancing resistor 18 if the one or more heaters 17 have a resistance within a range defined by 100 mΩ to 100 Ω, 200 mΩ to 10 Ω, 500 mΩ to 1 Ω, or any of these values.

[0031] 5a-5e collectively, the heat conduits 19 may include any suitable heat transfer medium for efficiently transferring heat from the heater 17 to the battery cells 12. In some embodiments, the heat conduits 19 include air conduits that transfer heat by convection. In other embodiments, the heat conduits include heat transfer pipes that transfer heat by conduction.

[0032] 5a schematically illustrates an exemplary battery system 10 configured for thermal management of battery cells 12, according to some embodiments. In the illustrated battery system 10, each battery cell 12 is coupled to a dedicated heater 17 by a dedicated conduit 19. In these embodiments, each heater 17 is located physically closer to a dedicated switch 16 than to the dedicated battery cell 12. The switch 16, heater 17, and controller 26 are integrated as part of the BMS 14.

[0033] In some embodiments, the switch 16, heater 17 and control unit 26 may be integrated onto a common substrate, for example in a manner similar to that shown in Figure 3b.

[0034] FIG. 5b schematically illustrates an exemplary battery system 10 configured for thermal management of battery cells 12 according to some other embodiments. In the illustrated battery system 10, each battery cell 12 is coupled to a dedicated heater 17 by a dedicated conduit 19. However, unlike the battery system 10 illustrated in FIG. 5a, in these embodiments, each heater 17 is physically located closer to its dedicated battery cell 12 than its dedicated switch 16. In the illustrated arrangement, the switch 16 and controller 26 are integrated as part of the BMS 14, while the heater 17 may be formed external to the BMS 14, e.g., integrated as part of the battery pack.

[0035] 5a-5b, a dedicated heater 17 is provided for each battery cell 12. However, embodiments are not limited thereto, and in other embodiments, there may be fewer or more heaters 17 than battery cells 12 configured to heat multiple battery cells 12. For example, one central heater 17 may be configured to deliver heat to each battery cell 12 as described herein.

[0036] FIG. 5c schematically illustrates an exemplary battery system 10 configured for thermal management of battery cells 12 according to some other embodiments. In the exemplary battery system 10, one or more heaters 17, e.g., a single P2H element, are electrically coupled to multiple switches 16, each centrally coupled to a battery cell 12. The single heater 17 dissipates power from the battery cell 12 when the one or more switches 16 are activated. The single heater 17 may be comprised of multiple resistors 18 mounted on a single circuit board. The single heater 17 is centrally thermally coupled to the multiple battery cells 12 via one or more thermal conduits 19, e.g., dedicated thermal conduits. As shown in FIG. 5b, the switches 16 and controller 26 are integrated as part of the BMS 14, while the heater 17 may be formed external to the BMS 14, e.g., integrated as part of a battery pack.

[0037] FIG. 5d schematically illustrates an exemplary battery system 10 configured for thermal management of battery cells 12 according to some other embodiments. In the illustrated battery system 10, one or more heaters 17, e.g., a single P2H element, are wirelessly centrally coupled to multiple switches 16, each coupled to a battery cell 12. The wireless coupling is configured to communicatively couple and wirelessly activate the heaters 17 via the one or more switches 16. In a manner similar to the battery system of FIG. 5c, the single heater 17 is, in turn, centrally thermally coupled to multiple battery cells 12 via one or more thermal conduits 19, e.g., dedicated thermal conduits. Similar to the battery system 10 illustrated in FIG. 5b, the switches 16 and controller 26 are integrated as part of the BMS 14, while the heaters can be formed external to the BMS, e.g., integrated as part of a battery pack.

[0038] 5a-5d, one or more heaters 17 are activated when one or more switches 16 are activated. In some embodiments, each of these systems can be configured to allow one or more heaters 17 to be actively cooled, for example, to prevent overheating.

[0039] FIG. 5e schematically illustrates an exemplary battery system 10 configured for thermal management of battery cells 12 according to some other embodiments. In the illustrated battery system 10, one or more heaters 17, e.g., a single P2H element, are centrally electrically coupled to multiple switches 16, each coupled to a battery cell 12, in a manner similar to that described for FIGS. 5c and 5d. The heaters 17 actively cool to dissipate excess heat once a target temperature is reached. The exemplary battery system 10 also includes a cooling unit that actively cools the heaters 17. The cooling unit may include any suitable cooling means, including air cooling and liquid cooling.

[0040] Thermal management method for battery systems FIG. 6a is a flow chart illustrating a thermal management method for the battery system 10 according to some embodiments. FIG. 6b is a flow chart illustrating a thermal management method for the battery system 10 according to other some embodiments. According to various embodiments, a thermal management method for the battery system 10 includes step 40 of sensing a state of charge (SoC) of each of a plurality of battery cells electrically coupled to one another. The method further includes step 41 of dissipating power from one or more battery cells having an SoC above a pre-established critical value by one or more heaters to generate heat by activating one or more switches coupled to the battery cells. The method further includes step 42 of transmitting heat generated from the one or more heaters to at least one battery cell via one or more thermal conduits to raise the temperature by at least 5° C. The thermal management method can be implemented in any battery system 10 disclosed herein.

[0041] Referring to FIG. 6a, the method includes step 40 of sensing the state of charge (SoC) of each of a plurality of battery cells electrically coupled together.

[0042] In some embodiments, the battery cells may be charged or discharged as shown in step 50 of Figure 6b before sensing the SoC of each battery cell 12 as shown in Figure 6a. The controller 26 (Figures 5a-5e) may sense the SoC of each battery cell 12.

[0043] 6b, in some embodiments, sensing the SoC of each battery cell includes measuring or sensing the cell voltage of each battery cell, as shown in step 51. The controller may measure the cell voltage of each battery cell.

[0044] In some embodiments, the method further includes, before performing the operation, determining whether the average cell voltage reaches the target voltage from the measured cell voltages of the battery cells in step 52. The controller 26 may, before performing the operation, determine whether the average cell voltage reaches the target voltage from the measured cell voltages of the battery cells. If it is determined in step 52 that one or more battery cells have an SoC exceeding a predetermined critical value, for example, as indicated by the battery cell voltage, the method may apply a cell balancing scheme to balance the battery cells. On the other hand, if it is determined in step 52 that no cells have an SoC or cell voltage above the predetermined critical value, the method may return to step 50 to charge or discharge the battery cells. For example, the target voltage for charging or discharging may be approximately 1.0 V, 1.5 V, 2.0 V, 2.5 V, 3.0 V, or a value within a range defined by any of these values, for example, approximately 1.2 V.

[0045] 6b, after determining that the average cell voltage reaches the target voltage in step 52 after charging and discharging in step 50, the method proceeds to determining whether to trigger a cell balancing method in step 53 and / or whether to heat the battery cells in step 57. The control unit 26 may determine whether to trigger the cell balancing method in step 53 and / or whether to heat the battery cells in step 57. For example, the abnormal parameter may be a relatively high range of SoC or cell voltage. For example, the abnormal parameter may be a relatively high range of SoC or cell voltage. In this example, if it is determined that the SoC range or cell voltage range measured from the battery cells 12 is outside a previously set range, the cell balancing method may be triggered. For example, if the cell voltage range exceeds a value within a range defined by 20 mV, 40 mV, 60 mV, 80 mV, 100 mV, or any value thereof, for example, 50 mV, the method may trigger a cell balancing scheme in step 53 according to some embodiments, as shown in Figure 6b. That is, the controller may measure the cell voltage in step 51 to sense the SoC, and selectively activate one or more switches when the controller measures a cell voltage range of approximately 50 mV or greater.

[0046] Referring further to FIG. 6A, the method further includes step 41 of dissipating power from one or more battery cells 12 having an SoC equal to or greater than a predetermined critical value via one or more heaters to generate heat by activating one or more switches 16 coupled to the battery cells 12 after sensing the SoC. The controller 26 may dissipate power from one or more battery cells 12. Dissipating power may occur when a cell balancing scheme is triggered. For example, the cell balancing scheme according to step 53 shown in FIG. 6B may be configured to selectively dissipate power from battery cells having an SoC, e.g., cell voltage, higher than a predetermined value. For example, the predetermined value may be an average cell voltage. For example, if the target charge / discharge voltage is 1.2 V, the switches 16 corresponding to battery cells having cell voltages greater than 1.2 V are activated to trigger the cell balancing scheme in step 53. That is, the controller 26 senses the SoC by measuring cell voltages in step 51, as shown in FIG. 6B, and selectively activates one or more switches when the average cell voltage is greater than approximately 1.2 V.

[0047] 6a, in connection with power dissipation, the method further includes step 42 of transmitting heat generated from one or more heaters 17 to at least one of the battery cells 12 via one or more thermal conduits 19 to raise the temperature by at least 5°C. In some embodiments, before transmitting the heat, a temperature control loop may be initiated to sense the temperature of the battery cells, as shown in step 54 of FIG. 6b, to determine whether to heat the battery cells 12, as shown in step 55 of FIG. 6b. In these embodiments, the method further includes measuring the temperature of at least one of the battery cells before transmitting the heat. The temperature of the battery cells 12 may be measured using one or more temperature sensors 13 disposed adjacent to the one or more battery cells 12.

[0048] If it is determined in step 55 that the measured temperature exceeds the preset value, then instead of activating the switch to heat the battery cell, the method may cool the battery cell to a temperature below the preset temperature as shown in step 56 of Figure 6b, in which case the method returns to the beginning of the method, step 50, shown in Figure 6b.

[0049] On the other hand, if it is determined in step 55 that the measured temperature does not exceed the preset value, the method proceeds by transferring heat in step 57 of FIG. 6b. According to an embodiment, the preset temperature may be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, or a value within a range defined by any of these values, depending on the application of the battery system 10 and the type of battery cell 12. For example, when integrated as part of the ESS 30, the battery cell 12 may be heated within a range of, for example, 20 to 30°C. If the battery cell is a redox battery cell, e.g., a vanadium ion battery cell, the battery cell may be heated within a range of 15 to 40°C.

[0050] After the battery cells have been heated to a pre-set temperature or heating has commenced in step 57, the method proceeds to charging and discharging the battery cells in step 50, as shown in FIG. 6b.

[0051] Energy storage system for thermal management of battery cells According to various embodiments described above, thermal management of the battery cells 12 of the battery system 10 may be accomplished using one or more heaters 17 electrically configured to generate heat by dissipating power from the battery cells 12 upon activation, and one or more thermal conduits 19 that route the heat generated by the one or more heaters 17 to at least one of the battery cells 12. When integrated as part of an energy storage system (ESS) 30, additional or alternative thermal management features may be implemented as described herein.

[0052] FIG. 7a schematically illustrates an energy storage system 30 configured for thermal management of battery cells 12 according to various embodiments. The illustrated ESS 30 may include similar features as those described above with respect to FIG. 4b, and a detailed description thereof will not be provided here for brevity. It will be appreciated that in other embodiments, the ESS 30 may be configured in a manner similar to that shown in FIG. 4a. The illustrated PCS 32 is electrically coupled to the battery system 10 and the load 36. In a manner similar to the ESS 30 described above with respect to FIG. 4b, the PCS 30 is configured to receive power, e.g., AC power, from the grid 34 and control the power, e.g., DC power, delivered to the battery system 10 and the load 36.

[0053] 7a, the illustrated energy storage system (ESS) 30 includes a battery system 10 including a plurality of battery cells 12 electrically coupled to one another, a plurality of switches 16 each coupled to one of the battery cells 12, and one or more heaters 17 (or resistors 18) electrically coupled to the switches 16 for actively or passively balancing the state of charge (SoC) of the battery cells 12. The ESS 30 may further include a power control system (PCS) 32 electrically coupled to the battery system 10. The ESS 30 may further include an electrical load 36 electrically coupled to the PCS 32.

[0054] In some embodiments, one or both of the PCS 32 and the electrical load 36 are configured to be electrically coupled to the grid 34. Additionally, one or more of the battery system 10, the PCS 32, and the electrical load 36 are insulated from air by a thermal insulator 38. The thermal insulator 38 may include, for example, without limitation, a polymeric material such as polypropylene, polyester, or polyimide, a paper-based material, or a glass-based material. The thermal insulator 38 recovers heat generated by the PCS 32 to heat the battery cells 12. The thermal insulator 38 enhances heat conservation for efficient and rapid heating of the battery cells 12 using any of the battery system 10 configurations described. The inventors have found that to this end, the insulator 38 has a thermal conductivity within a range defined as 0.01 to 0.2, 0.2 to 0.4, 0.4 to 0.6, or 0.8 to 1 W / m·K, or any of these values. Thus, as shown, the insulation 38 can provide a partially or completely thermally closed ESS 30 for efficient heating of the battery cells 12 .

[0055] In the illustrated embodiment, the battery system 10 and the PCS 32 are insulated by air as well as the insulation 38. However, embodiments are not limited thereto, and in other embodiments, one or more of the battery system 10, the PCS 32, and the electrical load 36 may be insulated from one another by air as well as the insulation 38. For example, in some embodiments, the battery system 10, the PCS 32, and the electrical load 36 may all be insulated by the insulation 38.

[0056] As described herein, the electrical load 36 may be any component, element, device, or system intended to be powered by the battery system 10. Examples of the electrical load 36 include, for example, the BMS 14, the PCS 32, a data center, a deep learning center, a blockchain mining center, and an electric vehicle. In one particular embodiment, when the electrical load 36 includes an electric vehicle, heat generated by the electric vehicle can be further recovered to heat the battery cells 12. In this embodiment, a charging station or garage housing the electric vehicle can be considered to be included as part of the thermally closed ESS system 30.

[0057] According to various embodiments, when insulating the battery system 10, one or more of its components can be selectively isolated. That is, any of the battery cells 12, the switch 16, the one or more heaters 17, and the one or more thermal conduits 19 of the battery system 10 as described above can be encapsulated in a non-air insulating material 38. Figures 7b and 7c show two exemplary implementations.

[0058] 7b schematically illustrates a battery system 10 configured for thermal management of battery cells according to some embodiments. In the illustrated embodiment, the battery cells 12 and one or more heaters 17 are encapsulated in insulation 38. For example, a battery rack housing the battery cells 12 may be insulated, and the battery cells 12 and heaters 17 may be housed within.

[0059] 7c schematically illustrates a battery system 10 configured for thermal management of battery cells 12, according to some other embodiments. In the illustrated implementation, the battery cells 12 and one or more heaters 17 are encapsulated in thermal insulator 38 in a manner similar to the embodiment illustrated in FIG. 7b. Also encapsulated in the illustrated embodiment is the BMS 14, including switches 16 and controller 26. For example, a battery rack housing the battery cells 12 may be insulated and may house the battery cells 12, heaters 17, and BMS 14 therein.

[0060] FIGURE 7d schematically illustrates an energy storage system 30 configured for thermal management of battery cells 12, according to various alternative embodiments. The illustrated ESS may include similar features as those described above with respect to FIGURES 4b and 7a, and for the sake of brevity, a detailed description will not be provided here. However, it will be appreciated that in alternative embodiments, the ESS 30 may be configured in a manner similar to that shown in FIGURE 4a.

[0061] 7d, an energy storage system (ESS) 30 is shown including a battery system 10 including a plurality of battery cells 12 electrically coupled to one another, a plurality of switches 16 each coupled to one of the battery cells 12, and one or more heaters 17 (or resistors 18) electrically coupled to the switches 16 for actively or passively balancing the state of charge (SoC) of the battery cells 12. The ESS further includes a power control system (PCS) 32 electrically coupled to the battery system 10. The ESS 32 further includes an electrical load 36 electrically coupled to the power control unit 32. One or both of the PCS 32 and the electrical load 36 are thermally coupled to the battery system 10 by one or more thermal conduits 19 that transmit heat generated by one or both of the PCS 32 and the electrical load 36 to at least one battery cell 12 to increase the temperature of the battery cell. The battery system 10 may be according to any of the embodiments described above.

[0062] According to various embodiments, the thermal conduits 19 may include any suitable thermally conductive medium for efficiently conducting heat from the PCS 32 and / or the electrical load 36 to the battery cells 12. In some embodiments, the thermal conduits 19 include air conduits that transfer heat by convection. The air conduits may include, for example, at least partially enclosed tubular conduits that transport heated air. In other embodiments, the thermal conduits 19 include thermally conductive pipes that transport heat by conduction. The thermally conductive pipes may include, for example, solid or hollow pipes filled with a thermally conductive medium, such as a metal or other solid-state thermally conductive material. In still other embodiments, the thermal conduits 19 include thermally conductive pipes or conduits that transport heat by a combination of conduction and convection. The thermally conductive pipes may include, for example, hollow pipes filled with a thermally conductive medium, such as a liquid, that is heated by one or both of the PCS 32 and the electrical load 36 by conduction, and then transports the heated liquid to the battery cells 12 by convection.

[0063] 7d, in the illustrated embodiment, the battery system 10 is insulated, while the PCS 32 and the electrical load 36 are not. However, the illustrated configuration is merely exemplary, and the embodiments are not limited thereto. For example, according to other embodiments, one or both of the PCS 32 and the electrical load 36 may be insulated from one another by non-air insulation 38, as described above with respect to FIG. 7a.

[0064] Additionally, according to various embodiments of the present invention, when insulating the battery system 10, one or more of its components can be selectively insulated. That is, any of the battery cells 12, the switch 16, the one or more heaters 17, and the one or more thermal conduits 19 of the battery system 10 as described above can be encapsulated with a non-air insulating material 38. Figures 7a and 7b show two exemplary implementations.

[0065] Redox battery system with thermal management As previously mentioned, other competitive factors considered in selecting and designing an appropriate electrochemical energy storage system for a particular application include investment cost, power, energy, lifespan, recyclability, efficiency, scalability, and maintenance costs. Among various electrochemical energy storage systems, redox batteries (RBs) are considered preferable for stationary energy storage. RBs are electrochemical energy conversion devices that use the oxidation-reduction process of redox species dissolved in a solution. Some favorable features of RBs are their independent scalability of power and energy, high depth of discharge (DOD), and reduced environmental impact. These features enable a wide range of operating power and discharge times, making RBs suitable for storing electricity generated from renewable resources.

[0066] In view of the battery system aspects disclosed herein, RB may be particularly suitable for various embodiments of the battery system, thermal management method, and energy storage system disclosed herein. One such advantage arises from the fact that the redox chemical reactions that govern the charging and discharging of redox batteries can accelerate at elevated temperatures, for example, due to Arrhenius behavior. While obtaining such advantages, the risk of overheating and / or explosion is relatively low for RB compared to lithium-ion batteries, making RB particularly suitable for implementing various embodiments of the thermal management methods disclosed herein.

[0067] Thus, according to various embodiments disclosed herein, thermal management features relate to redox batteries. FIG. 8a is a schematic diagram of an embodiment of a redox battery. The illustrated redox battery 200A includes a first half-cell 204A and a second half-cell 204B. The first half-cell 204A includes a positive electrolyte reservoir 106A having a first or positive electrolyte disposed therein in contact with the positive electrode. The first electrolyte contains a first redox couple dissolved therein, in which a first redox half-reaction occurs. The second half-cell 204B includes a negative electrolyte reservoir 106B having a second or negative electrolyte disposed therein in contact with the negative electrode. The second electrolyte contains a second redox couple dissolved therein, in which a second redox half-reaction occurs. The positive and negative electrolyte reservoirs 106A, 106B define reaction spaces for their respective half-reactions. The redox battery 200A further includes an ion exchange membrane 112 separating the positive electrolyte reservoir 106A and the negative electrolyte reservoir 106B. The positive electrode is electrically connected to the positive current collector 108A, and the negative electrode is electrically connected to the negative current collector 108B. In some embodiments, a first bipolar plate 208A is interposed between the positive current collector 108A and the positive electrolyte reservoir 106A, and a second bipolar plate 208B is interposed between the negative current collector 108B and the negative electrolyte reservoir 106B.

[0068] Unlike a conventional RB, in the redox battery 200, the first half-cell 204A, the second half-cell 204B, and the ion exchange membrane 112 define a redox battery cell enclosed in a casing or frame 212. The enclosed casing 212 ensures that its internal contents are not physically accessible from the outside during normal operation. That is, the positive and negative electrolytes are not in fluid communication with an external container, such as an electrolyte tank. The casing 212 completely and / or permanently encloses the redox battery 200A. This configuration contrasts with a conventional redox flow battery, in which the redox battery cell is in fluid communication with an external tank. That is, in a redox battery, neither the positive electrolyte reservoir 106A nor the negative electrolyte reservoir 106B of the enclosed cell is in fluid communication with or physically connected to a separate electrolyte tank that stores the first or second electrolyte, respectively. In this manner, substantially the entire volume of positive and negative electrolytes is stored within the redox battery and hermetically enclosed by the casing 212. That is, the first electrolyte reservoir 106A stores substantially the entire volume of the first electrolyte for the first half-cell 204A, and the second electrolyte reservoir 106B stores substantially the entire volume of the second electrolyte for the second half-cell 204B. In part because the redox battery 200A is not separately connected to a storage tank, the redox battery 200A preferably does not include conduits for conveying electrolyte to and from the battery cells or pumps for circulating the electrolyte.

[0069] As previously mentioned, a notable structural feature of the redox battery 200A compared to conventional redox batteries, such as redox flow batteries (RFBs), is the omission of a pump. Instead, in the redox battery 200A according to the embodiment, first and second electrolytes circulate naturally within the positive electrode electrolyte reservoir 106A of the first half-cell 204A and the negative electrode electrolyte reservoir 106B of the second half-cell 204B. In various configurations, the self-circulation of the first and second electrolytes is driven by one or more of the following: an osmotic pressure difference between the first and second electrolyte reservoirs; density changes in one or both of the first and second electrolytes; diffusion or migration of one or both of the first and second electrolytes; affinity of one or both of the first and second electrolytes for the first and second electrodes, respectively; the first and second redox half-reactions; and thermal expansion or contraction of one or both of the first and second electrolytes. The inventors have found that self-circulation is effective in providing stability in power and energy output if the thickness of the positive and negative electrolyte reservoirs 106A, 106B in the cross-sectional view of FIG. 8a does not exceed 20 cm, 15 cm, 10 cm, 5 cm, 2 cm, 1 cm, or a value within a range defined by any of these values.

[0070] Referring to FIG. 8a, the casing 212 is formed of a suitable corrosion-resistant material to accommodate the positive and negative electrolytes, which can be highly acidic. In addition to providing corrosion resistance, the casing 212 may be rigid to provide mechanical support for the redox battery 200. In some embodiments, at least a portion of the casing 212 may be formed of a flexible material that deforms to accommodate changes in internal pressure within the positive and negative electrolyte reservoirs 106A, 106B. Increases in internal pressure may be caused, for example, by various effects described below for pressure-regulated redox batteries. In configurations where only a portion of the casing is formed of a flexible material, the remainder may be formed of a rigid material. For example, the flexible portion may be configured to expand with increased pressure to accommodate increases in volume of one or both of the positive and negative electrolyte reservoirs 106A, 106B of greater than 0.1%, 0.2%, 0.5%, 1%, 2%, 5%, 10%, 20%, or 50%. Suitable materials for the casing 212 may include polyvinyl chloride (PVC), polyethylene (PE), polystyrene (PS), polypropylene (PP), polycarbonate (PC), ABS, reinforced plastics, and the like.

[0071] The redox battery 200A configured in this manner offers various technical and commercial advantages. For example, various reliability issues associated with the pump for circulating the electrolyte as well as the conduits between the battery cells and the tank, e.g., pipe joints, are effectively reduced or eliminated, thereby reducing safety hazards, operational costs, and unplanned repairs associated with the operation of the redox battery 200A. Furthermore, external efficiency is substantially improved by eliminating the need to circulate the electrolyte between the battery cells and the tank using a pump. By eliminating the need to circulate the electrolyte between the cells and the electrolyte tank, the redox battery 200A can achieve power densities up to 2 to 50 times higher than conventional RFBs, depending on the system size. As previously mentioned, power density refers to the power or energy output of a storage device relative to the total volume of the energy storage device. Therefore, in the case of a redox battery, power or energy density refers to the ratio of power or output to the total volume of the redox battery. Furthermore, space efficiency is further improved by eliminating the need for a separate circulation system, including a tank, pump, and conduits. Moreover, the system complexity is significantly reduced, significantly lowering the barriers to commercial implementation of the redox battery 200A. For example, unlike conventional RFBs, the redox battery 200A can be manufactured in packs similar to lithium-ion batteries for modular implementation, eliminating the need for intrusive structures required to install conventional RFBs and making it more suitable for automation and mass production.

[0072] In the following, the operating principles and aspects of redox battery 200A are described using the example of a vanadium redox battery based on a vanadium (V)-based redox couple, but it will be understood that embodiments are not so limited and that the principles described herein may be applied to redox batteries with various other redox couples.

[0073] In an example V redox battery, the first redox couple dissolved in the first or positive electrolyte of the first half-cell 204A is V 4+ / V 5+The second redox couple dissolved in the second or negative electrolyte of the second half-cell 204B may be a redox couple, V 2+ / V 3+ The redox reaction during charging and discharging can be described using the following equation, where → indicates the discharge reaction direction and ← indicates the charge reaction direction: Second half-cell / negative electrode: V 2+ ←→V 3+ +e - First half cell / positive electrode: V 5+ +e - ←→V 4+ Overall response: V 2+ +V 5+ ←→V 3+ +V 4+

[0074] During charging, in the first half-cell 204A, V 4+ The tetravalent vanadium in the ion is V 5+ In the second half-cell 204B, the vanadium ions are oxidized to pentavalent vanadium, while in the second half-cell 204B, the vanadium ions are oxidized to trivalent vanadium. 3+ is a divalent ion V 2+ During discharge, in the first half-cell 204A, V 5+ The pentavalent vanadium in the ion is V 4+ In the second half-cell 204B, the ions are reduced to tetravalent vanadium, while in the second half-cell 204C, the ions are reduced to divalent ions V 2+ is a trivalent ion V 3+ During these redox reactions, electrons are transferred through an external circuit and specific ions diffuse across the ion exchange membrane 112, balancing the electroneutrality of the positive and negative half-cells, respectively.

[0075] Other redox reactions can be implemented in redox battery 200A according to embodiments. In various embodiments, the first redox couple and / or the second redox couple include one or more ions of vanadium (V), zinc (Zn), bromine (Br), chromium (Cr), manganese (Mn), titanium (Ti), iron (Fe), cerium (Ce), and cobalt (Co). In some embodiments, the first and second redox couples include the same metal ions, such as the V redox battery described above. In these embodiments, mixing of the positive and negative electrode electrolytes preferably does not result in cross-contamination of these electrolytes.

[0076] As previously mentioned, the electrolyte of a redox battery is a solution that conducts electrical current through ionization. The electrolyte supports the reduced and oxidized forms of a redox couple, as well as the cation and anion, to balance the charge of the ions in the solution during oxidation and reduction of the redox couple. In one embodiment, the positive and negative electrode electrolytes comprise an acidic aqueous solution. In the case of a V redox battery, the concentration of V ions is related to the energy density of the electrolyte. A higher energy density can preferably serve to reduce the volume of the positive and negative electrode electrolyte reservoirs 106A, 106B required for a given amount of energy and power output. However, very high V ion concentrations can reduce the stability of V ions. Thus, there is an optimal range of V ions for a given application. For example, the vanadium ions dissolved in one or both of the first and second electrolytes may be greater than 1.0 M, 1.5 M, 2.0 M, 2.5 M, or values ​​within the ranges defined by any of these values. On the other hand, V ion concentrations below 1.0 M may result in energy levels that are not suitable for some applications. On the other hand, a concentration of V ions greater than 2.5 M, for example, at operating temperatures above 50 °C, 5+ The ionic stability may be even lower, e.g., at operating temperatures below -20°C, the V 2+ and V 3+ The solubility limit of the ion can be reached.

[0077] Preferably, according to some embodiments, the positive and negative electrode electrolytes may contain the same solvent and / or ions of the same metal. In such embodiments, mixing of the positive and negative electrode electrolytes through the ion exchange membrane 112 prevents contamination of each half-cell. Also, the positive and negative electrode electrolytes may be prepared from the same starting solvent and solute. For example, in the case of a V redox battery according to some embodiments, both the positive and negative electrode electrolytes contain sulfuric acid. Tetravalent vanadium ions (V 4+ ) and / or trivalent vanadium ions (V 3+ For example, an electrolyte can be prepared by dissolving 0.1M to 2.5M vanadyl sulfate (VSO4) in an aqueous solution with 0.1M to 6M H2SO4. The tetravalent / trivalent vanadium ions are electrochemically oxidized to form the positive electrode electrolyte (negative electrode solution), which is converted to pentavalent vanadium ions (V 5+ ) solution. Conversely, the tetravalent / trivalent vanadium ions are electrochemically reduced to form the negative electrode electrolyte (cathode solution), which is converted to divalent vanadium ions (V 2+ ) solution.

[0078] Referring to FIG. 8a, in various embodiments, the positive and negative electrodes disposed in the positive and negative electrolyte reservoirs 106A, 106B, respectively, comprise carbon-based materials, such as carbon or graphite felt, carbon cloth, carbon black, graphite powder, and graphene. The carbon-based materials preferably provide a relatively high operating range, excellent stability, and high reversibility. The electrodes are optimized for relatively high electrochemical activity, low bulk resistivity, and large non-surface area. Improving the electrochemical activity of the electrodes increases the energy efficiency of the redox battery 200A. To improve the performance of the redox battery 200A, the surfaces of the electrodes can be modified, for example, by coating with a metal to increase surface roughness or by doping with an additive.

[0079] The positive and negative electrode electrolyte reservoirs 106A, 106B, if present, defining the reaction spaces are partially or completely filled with the respective electrodes between the ion exchange membrane 112 and the first and second positive electrode plates 208A, 208B, respectively, and between the ion exchange membrane 112 and the positive and negative electrode current collectors 108A, 108B, respectively. After filling the respective electrodes, the remaining spaces of the positive and negative electrode electrolyte reservoirs 106A, 106B, if present, are partially or completely filled with the respective electrolytes between the ion exchange membrane 112 and the first and second positive electrode plates 208A, 208B, respectively, and between the ion exchange membrane 112 and the positive and negative electrode current collectors 108A, 108B, respectively. In various embodiments, unless intentionally perforated or porous as described below, the ion exchange membrane 112 substantially separates the two half-cells, substantially preventing mixing of the two electrolytes and redox couples, and providing H to balance the charge between the two half-cells to complete the circuit while current is flowing. + The ion exchange membrane 112 allows the transport of ions such as ions. The ion exchange membrane 112 may be an anion exchange membrane or a cation exchange membrane. The ion exchange membrane 112 may include several categories of materials, such as perfluorinated ionomers, partially fluorinated polymers, and non-fluorinated hydrocarbons. Specific examples of ion exchange membranes 112 include Nafion®, Flemion®, NEOSEPTA-F®, and Gore Select®, which offer excellent chemical stability, high conductivity, and mechanical strength.

[0080] While the various embodiments shown include, but are not limited to, ion exchange membranes 112 that may be selective for particular ion types, such as anions or cations, for example, in various embodiments, ion exchange membranes 112 may be non-selective membranes, such as porous membranes.

[0081] Referring to FIG. 8a, in some embodiments, output power can be expanded by connecting multiple single redox battery cells, for example, in series, to form a cell stack. In such a configuration, first and second positive electrode plates 208A, 208B facilitate the series connection of single cells, eliminating the need for current collectors 108A, 108B between adjacent positive electrode plates. The first and second positive electrode plates 208A, 208B are formed of a suitable material, such as graphite, carbon, carbon plastic, etc., to provide high electrical conductivity and low internal resistance to the cell stack. The first and second positive electrode plates 208A, 208B also support contact pressure when pressed against the electrodes to increase electrical conductivity. Furthermore, the first and second positive electrode plates 208A, 208B are provided with high acid resistance to prevent corrosion and oxidation of the current collectors 108A, 108B.

[0082] The positive and negative electrode current collectors 108A, 108B contain a metal with high electrical conductivity, such as copper or aluminum, and function to pass current during charge and discharge processes.

[0083] Since the single redox battery 200A described above has an output voltage characterized by an electrochemical reaction of, for example, about 1.65 V or less, additional cells can be electrically connected in series or parallel to achieve even higher voltages and currents, respectively, as described above.

[0084] FIG. 8b is a schematic diagram of a redox battery including multiple sealed redox battery cells in a stacked configuration, according to some embodiments. The illustrated redox battery 200B includes multiple stackable battery cells 200B-1, 200B-2, ..., 200B-n, each configured in a manner similar to redox battery 200A (FIG. 2a) (FIG. 8a). Each of the multiple battery cells 200B-1, 200B-2, ..., 200B-n includes a positive electrode electrolyte reservoir 106A, a negative electrode electrolyte reservoir 106B, and an ion exchange membrane 112. In the illustrated embodiment, each of the multiple battery cells 200B-1, 200B-2, ..., 200B-n is separately surrounded by a casing 212. The multiple battery cells 200B-1, 200B-2, ..., 200B-n are electrically connected in series to increase the output voltage.

[0085] 8c is a schematic diagram of a redox battery including multiple redox battery cells in a stacked configuration, according to some other embodiments. The illustrated redox battery 200C includes multiple stackable battery cells 200C-1, 200C-2, ..., 200C-n, each of which is configured in a manner similar to redox battery 200A (FIG. 8a), including a positive electrolyte reservoir 106A, a negative electrolyte reservoir 106B, and an ion exchange membrane 112. However, unlike redox battery 200B (FIG. 8B), in the illustrated embodiment, the multiple battery cells 200C-1, 200C-2, ..., 200C-n are surrounded by a common casing 222. In a manner similar to redox battery 200B (FIG. 8b), multiple battery cells 200C-1, 200C-2, ..., 200C-n are electrically connected in series to increase the output voltage. Also, in some embodiments, the positive electrode electrolyte reservoirs 106A of multiple battery cells 200C-1, 200C-2, ..., 200C-n can be in fluid communication with each other, and the negative electrode electrolyte reservoirs 106B of multiple battery cells 200C-1, 200C-2, ..., 200C-n can be in fluid communication with each other. Redox battery 200C can be constructed as a pouch-type battery or a rigid-case type battery.

[0086] 8d is a schematic diagram of a redox battery including multiple redox battery cells in a cylindrical stacked configuration, according to an embodiment. The illustrated redox battery 200D includes multiple cylindrically stackable battery cells 200D-1, 200D-2, ..., 200D-n, each of which is configured in a manner similar to redox battery 200A (FIG. 8a), including a positive electrolyte reservoir 106A, a negative electrolyte reservoir 106B, and an ion exchange membrane 112. The multiple battery cells 200D-1, 200D-2, ..., 200C-n may be individually enclosed in casings in a manner similar to that described above for redox battery 200B (FIG. 8b). Alternatively, the plurality of battery cells 200D-1, 200D-2, ..., 200C-n may be enclosed in a common casing 222 in a manner similar to that described above for redox battery 200C (FIG. 8c). In a manner similar to redox battery 200B (FIG. 8b), the plurality of battery cells 200D-1, 200D-2, ..., 200D-n may be electrically connected in series to increase the output voltage. Also, in some embodiments, the positive electrode electrolyte reservoirs 106A of the plurality of battery cells 200D-1, 200D-2, ..., 200D-n may be in fluid communication with one another, and the negative electrode electrolyte reservoirs 106B of the plurality of battery cells 200D-1, 200D-2, ..., 200D-n may be in fluid communication with one another.

[0087] In each of the stacked configurations described above with respect to Figures 8b and 8c, it can be understood that some or all of the multiple battery cells are electrically connected in series by appropriately electrically connecting the opposite polarity current collectors of some or all of the cells, or are electrically connected in parallel by appropriately electrically connecting some of the same polarity current collectors of all the cells.

[0088] Further examples 1. A battery system includes a plurality of battery cells electrically coupled to each other, a plurality of switches each coupled to one of the battery cells, and one or more heaters electrically coupled to the switches and configured to generate heat when activating one or more of the switches by dissipating power from the battery cells, wherein the one or more thermal conduits are configured to transmit heat generated by the one or more heaters to at least one of the battery cells to increase its temperature.

[0089] 2. A battery system includes a plurality of battery cells electrically coupled to each other, a plurality of switches each coupled to one of the battery cells, and one or more heaters electrically coupled to the switches and configured to generate heat when activating one or more switches by dissipating power from the battery cells, wherein the heaters are configured to actively or passively balance the state of charge (SoC) of the battery cells and act as one or more resistors to increase the temperature of the battery cells by the heat.

[0090] 3. The battery system of Example 1 includes one or more heaters configured to act as one or more resistors to actively or passively balance the state of charge (SoC) of the battery cells.

[0091] 4. The battery system of Example 2 further includes one or more thermal conduits configured to transmit heat generated by the one or more heaters to at least one of the battery cells to increase its temperature.

[0092] 5. The battery system of any of the first to fourth embodiments has a plurality of battery cells that are oxidation-reduction cells.

[0093] 6. The battery system of any of Examples 1 to 5 further includes a control unit electrically connected to the battery cells and the switches, and the control unit is configured to sense a state of charge (SoC) of each of the battery cells and selectively activate one or more switches based on the sensed SoC.

[0094] 7. The battery system of Example 6 includes a control unit configured to selectively activate one or more switches coupled to the battery cells when the control unit detects that the SoC has fallen outside a previously set range.

[0095] 8. The battery system of Example 7 uses the sensed SoC, which is proportional to battery capacity and unique to each of the battery cells.

[0096] 9. The battery system of any of Examples 6 to 8 includes a controller configured to sense the state of charge (SoC) by measuring cell voltages and selectively activate one or more switches when measuring an average cell voltage greater than about 1.2 V.

[0097] 10. The battery system of any of Examples 6 to 9 includes a controller configured to sense the state of charge (SoC) by measuring cell voltages and selectively activate one or more switches when measuring a cell voltage range greater than about 50 mV.

[0098] 11. The battery system of any one of embodiments 1-10 further includes a plurality of temperature sensors, each configured to measure a temperature of at least one of the battery cells.

[0099] 12. The battery system of any of Examples 6 to 9 further includes a controller configured to activate the one or more switches when it determines that the temperature of at least one of the battery cells is lower than a preset temperature.

[0100] 13. The battery system of any of Examples 6 to 10 further includes a controller configured to activate the one or more switches after cooling at least one of the battery cells to a temperature lower than a previously set temperature.

[0101] 14. The battery system of any of Examples 6 to 11 includes a control unit configured to deactivate activated ones of the above switches when it detects that the temperature of at least one of the battery cells has increased by at least 5°C.

[0102] 15. The battery system of any one of embodiments 1 to 14 uses the heat generated by the one or more heaters to make the temperature of the at least one of the battery cells reach 20 to 30°C.

[0103] 16. The battery system of any one of Examples 1 to 15, wherein the heat conduit includes an air conduit that transfers the heat by convection.

[0104] 17. The battery system of any one of Examples 1 to 16 further includes a heat conduit including a heat conduction pipe that transfers the heat by conduction.

[0105] 18. The battery system of any of embodiments 1-17 uses the heat generated by dissipating power from the battery cells to be sent to the same battery cells.

[0106] 19. The battery system of any one of embodiments 1 to 17 uses the heat generated by dissipating power from the battery cells to be sent to different ones of the battery cells.

[0107] 20. In any one of the battery systems of Examples 1-19, each of the battery cells is a redox battery cell, the redox battery cell including: a first half-cell including a first electrolyte having a first redox couple dissolved therein configured for a first redox half-reaction to occur; a second half-cell including a second electrolyte having a second redox couple dissolved therein configured for a second redox half-reaction to occur; and an ion exchange membrane separating a positive electrode electrolyte reservoir and a negative electrode electrolyte reservoir, the redox battery cell storing chemical energy in the first and second electrolytes.

[0108] 21. The battery system of Example 20 has the first redox couple or the second redox couple including one or more ions of vanadium (V), zinc (Zn), bromine (Br), chromium (Cr), manganese (Mn), titanium (Ti), iron (Fe), cerium (Ce), and cobalt (Co).

[0109] 22. The battery system of Example 21 has first and second redox couples including V ions.

[0110] 23. The battery system of any one of Examples 1 to 22 is a redox battery cell comprising a redox flow battery cell that includes separate tanks for storing the first electrolyte and the second electrolyte outside the battery cell.

[0111] 24. In any one of the first to twenty-third embodiments, each of the battery cells of the battery system is connected to a dedicated heater among the heaters by a dedicated conduit among the conduits.

[0112] 25. Each heater in the battery system of Example 24 is physically located closer to a dedicated one of the switches than to a dedicated one of the battery cells.

[0113] 26. The battery system of Example 24 has a switch, heater, and control integrated as part of the battery management system.

[0114] 27. The battery system of Example 26 has the switch, heater, and control unit integrated on a common substrate.

[0115] 28. Each heater in the battery system of Example 24 is physically located closer to a dedicated one of the battery cells than to a dedicated one of the switches.

[0116] 29. The battery system of any of Examples 1 to 23 further includes a central heater electrically connected centrally to a number of the switches among the plurality of switches, and the central heater is thermally connected centrally to a number of the battery cells among the plurality of battery cells via the one or more thermal conduits.

[0117] 30. The battery system of any of Examples 1 to 23 has a central heater that is wirelessly connected to the multiple switches at a central location and thermally connected to the multiple battery cells at a central location via the one or more thermal conduits.

[0118] 31. The battery system of Examples 29 or 30 has the central heater being a single heater.

[0119] 32. The battery system of any one of Examples 1 to 31 includes a heater configured to actively cool to dissipate excess heat when a target temperature is reached.

[0120] 33. The battery system of any one of Examples 1 to 32 includes the one or more heaters having a resistance in the range of 100 mΩ to 100Ω.

[0121] 34. The battery system of any one of Examples 1 to 33 includes one or more of the battery cells, the switch, one or more of the heaters, and the one or more heat conduits encapsulated with a thermal insulator in addition to air.

[0122] 35. The battery system of Example 34 includes the respective battery cells encapsulated in thermal insulation, the one or more heaters, and the one or more thermal conduits.

[0123] 36. The battery system of Example 34 includes the respective battery cells, the switch, the one or more heaters, and the one or more thermal conduits encapsulated in a thermal insulator.

[0124] 37. The battery system of any one of Examples 34 to 36 includes a thermal insulator having a thermal conductivity of 0.01 to 1 W / m·K.

[0125] 38. In any of Examples 1 to 37, the battery system is electrically coupled to one or both of an external power control system and an external electrical load, and one or both of the external power control system and the external electrical load are thermally coupled to the battery system by an external thermal conduit configured to transmit heat generated by one or both of the external power control system and the external electrical load to at least one of the battery cells to increase their temperature.

[0126] 39. The battery system of any one of Examples 1 to 38, wherein the one or more heaters have a resistance of 100 mΩ to 100Ω.

[0127] 40. A thermal management method for a battery system, comprising: sensing a state of charge (SoC) of each of a plurality of battery cells electrically coupled to one another; dissipating power from one or more of the battery cells having an SoC above a pre-established critical value by activating one or more switches coupled to the battery cells via one or more heaters to generate heat; and transmitting heat generated from the one or more heaters via one or more thermal conduits to at least one of the battery cells to increase a temperature of the at least one.

[0128] 41. The battery system used in the method of Example 40 is any one of Examples 1 to 39.

[0129] 42. The method of example 40 or 41 includes charging and discharging the plurality of battery cells before sensing the SoC.

[0130] 43. The method of any of Examples 40-42 further includes charging and discharging the plurality of battery cells to an average cell voltage of about 1.0 to 2.0 V before sensing the SoC.

[0131] 44. Any of the methods of embodiments 40-43, wherein sensing the SoC includes measuring a cell voltage, and the predetermined critical value of the SoC corresponds to the average cell voltage.

[0132] 45. The method of any of Examples 40-44, further comprising activating a cell balancing scheme based on the sensed SoC.

[0133] 46. ​​In the method of Example 45, the step of activating the cell balancing scheme is activated upon determining that the cell voltage range exceeds a preset value of approximately 50 mV.

[0134] 47. The method of Example 46 further includes selectively activating the one or more switches coupled to the one or more battery cells having the SoC equal to or greater than the predetermined critical value when the range of the cell voltages exceeds the predetermined value.

[0135] 48. The method of any of Examples 40-46 further includes sensing the temperature of at least one of the battery cells before transmitting the heat.

[0136] 49. In the method of example 48, the step of transmitting heat includes the step of transmitting upon sensing that the temperature of at least one of the battery cells is less than a pre-set temperature.

[0137] 50. When it is sensed that the temperature of the at least one of the battery cells is equal to or greater than the preset temperature, the method of example 48 further includes a step of cooling the at least one of the battery cells to a temperature below the preset temperature.

[0138] 51. In the method of example 48 or 49, the step of transferring heat includes transferring heat until the temperature of the at least one of the battery cells reaches at least the predetermined temperature.

[0139] 52. The method of any one of Examples 48 to 51, wherein the battery cells include lithium ion battery cells, and the preset temperature is 20 to 30°C.

[0140] 53. The method of any of Examples 48-52, wherein each of the battery cells comprises a redox battery cell, and wherein the preset temperature of any of Examples 48-52 is 30-30°C.

[0141] 54. An energy storage system (ESS) includes a battery system, a power control system (PCS) electrically connected to the battery system, and an electrical load electrically connected to the power control unit, wherein the battery system includes a plurality of battery cells electrically connected to each other, a plurality of switches each connected to one of the battery cells, and one or more heaters electrically connected to the switches for actively or passively balancing the states of charge (SoC) of the battery cells, wherein one or both of the PCS and the electrical load are configured to be electrically connected to a grid, and the one or more battery systems, the PCS, and the electrical load are insulated from each other by an insulating material other than air having a thermal conductivity of 0.01 to 1 W / m·K.

[0142] 55. An energy storage system (ESS) includes a battery system, a power control system (PCS) electrically coupled to the battery system, and an electrical load electrically coupled to the power control unit, wherein the battery system includes a plurality of battery cells electrically coupled to each other, a plurality of switches each coupled to one of the battery cells, and one or more heaters electrically coupled to the switches for actively or passively balancing the states of charge (SoC) of the battery cells, and one or both of the PCS and the electrical load are thermally coupled to the battery system by one or more thermal conduits configured to direct heat generated by the PCS and one or both of the electrical load to at least one of the battery cells to increase its temperature.

[0143] 56. An energy storage system (ESS) includes a battery system, a power control system (PCS) electrically coupled to the battery system, and an electrical load electrically coupled to the power control unit, wherein the battery system includes a plurality of battery cells electrically coupled to each other, a plurality of switches each coupled to one of the battery cells, and one or more resistors electrically coupled to the switches for actively or passively balancing the state of charge (SoC) of the battery cells, and the battery system is according to any of Examples 1 to 37.

[0144] 57. The ESS of Example 54 has one or both of the PCS and the electrical load thermally coupled to the battery system by one or more thermal conduits configured to direct heat generated by the one or both of the PCS and the electrical load to at least one of the battery cells to increase its temperature.

[0145] 58. The ESS of Example 54 includes the battery system according to any one of Examples 1 to 39.

[0146] 59. The ESS of Example 55 has one or more of the battery systems, the PCS, and the electrical load insulated from each other by a thermal insulator that is not air and has a thermal conductivity of 0.01 to 1 W / m·K.

[0147] 60. The ESS of Example 55 includes the battery system according to any one of Examples 1 to 39.

[0148] 61. The ESS of Example 56 has one or more of the battery systems, the PCS, and the electrical load insulated from each other by an insulating material that is not air and has a thermal conductivity of 0.01 to 1 W / m·K.

[0149] 62. The ESS of Example 56 has one or both of the PCS and the electrical load thermally coupled to the battery cells by one or more thermal conduits configured to transmit heat generated by one or both of the PCS and the electrical load to the at least one of the battery cells to raise its temperature by at least 5°C.

[0150] Unless the context clearly requires otherwise, the words "comprise," "comprising," "including," and the like throughout the description and claims are to be interpreted in an inclusive sense, as opposed to an exclusive or exhaustive sense, i.e., meaning "including, but not limited to." The word "coupled," as used generally herein, refers to two or more elements, either directly connected or connected via one or more intermediate elements. Additionally, the words "herein," "above," "below," and similar meanings, when used herein, refer to this application as a whole, not to particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number, respectively. When referring to a list of two or more items, the word "or" includes any of the items in the list, any of the items in the list, and any combination of the items in the list.

[0151] Additionally, conditional language used herein, such as "can," "could," "would," "might," "example," "for example," "such as," and the like, is intended to generally convey that certain embodiments include certain features, elements, and / or conditions, but other embodiments do not, unless specifically stated otherwise or understood otherwise within the context in which it is used. Thus, such conditional language is not intended to generally imply that features, elements, and / or conditions are required in any way for one or more embodiments, or that these features, elements, and / or conditions may or may not be included in or performed in any particular embodiment.

[0152] Although specific embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. Indeed, the novel apparatus, methods, and systems described above may be embodied in a variety of other forms, and various omissions, substitutions, and modifications may be made to the methods and systems described herein without departing from the scope of the present disclosure. For example, while blocks are presented in a given arrangement, other embodiments may perform similar functions with other components and / or circuit topologies, and some blocks may be removed, moved, added, subdivided, combined, and / or modified. Each of these blocks may be embodied in a variety of different ways. Any suitable combination of elements and operations of the various embodiments described above may be combined to provide further embodiments. The various features and processes described above may be embodied independently of each other or combined in various ways. All possible combinations and subcombinations of features of the present disclosure are understood to be within the scope of the present disclosure.

Claims

1. a plurality of battery cells electrically connected to one another; a plurality of switches each connected to one of the plurality of battery cells; one or more heaters electrically coupled to the plurality of switches to dissipate power from the plurality of battery cells; one or more thermal conduits for transmitting heat generated by the one or more heaters to at least one of the plurality of battery cells; a cooling unit that actively cools the heater to dissipate excess heat when the heater reaches a target temperature; Including, Battery system.

2. The heat delivered by the one or more heat conduits causes the temperature of the at least one of the plurality of battery cells to reach 20 to 30°C. The battery system of claim 1 .

3. The heat conduit includes an air conduit that transfers the heat by convection. The battery system of claim 1 .

4. The heat conduit includes a heat conduction pipe that transfers the heat by conduction. The battery system of claim 1 .

5. the heat generated by dissipating power in the plurality of battery cells is transferred to the same battery cells that dissipate the power; The battery system of claim 1 .

6. The heat generated by dissipating power in the plurality of battery cells is transferred to the battery cells dissipating the power and other battery cells. The battery system of claim 1 .

7. a control unit electrically connected to the plurality of battery cells and the plurality of switches, the controller actively or passively balances the state of charge (SoC) of the battery cells using the one or more heaters; The battery system of claim 1 .

8. a control unit electrically connected to the plurality of battery cells and the plurality of switches, The controller senses a state of charge (SoC) of each of the plurality of battery cells and selectively activates one or more of the switches based on the sensed SoC. The battery system of claim 1 .

9. further comprising a plurality of temperature sensors each measuring a temperature of at least one of the plurality of battery cells; The battery system of claim 8 .

10. The control unit activates one or more of the switches when it is determined that the temperature of the at least one of the plurality of battery cells is lower than a preset temperature. The battery system of claim 8 .

11. the control unit cools the at least one of the plurality of battery cells to a temperature lower than a preset temperature, and then activates one or more of the switches; The battery system of claim 8 .

12. each of the plurality of battery cells is a redox battery cell; The redox battery cell comprises: a first half-cell containing a first electrolyte having a first redox couple dissolved therein in which a first redox half-reaction occurs; a second half-cell containing a second electrolyte having a second redox couple dissolved therein in which a second redox half-reaction occurs; an ion exchange membrane separating the first half-cell and the second half-cell; Including, The battery system of claim 1 .

13. sensing a state of charge (SoC) of each of a plurality of battery cells electrically connected to each other; dissipating power and generating heat from one or more of the battery cells having a state of charge above a predetermined critical value by one or more heaters by activating one or more switches coupled to the plurality of battery cells; transmitting heat generated from the one or more heaters to at least one of the plurality of battery cells via one or more thermal conduits; actively cooling the heater to dissipate excess heat when the heater reaches a target temperature; Including, Thermal management methods for battery systems.

14. and further comprising charging and discharging the plurality of battery cells before sensing the state of charge.

14. The method of thermal management of a battery system according to claim 13.

15. the step of sensing the state of charge includes measuring a cell voltage; The predetermined critical value of the state of charge is an average cell voltage.

14. The method of thermal management of a battery system according to claim 13.

16. and activating a cell balancing method based on the sensed state of charge.

14. The method of thermal management of a battery system according to claim 13.

17. and sensing a temperature of at least one of the plurality of battery cells prior to transmitting the heat.

14. The method of thermal management of a battery system according to claim 13.

18. The step of transmitting the heat includes a step of transmitting the heat when it is detected that the temperature of at least one of the plurality of battery cells is lower than a predetermined temperature.

20. The method of thermal management of a battery system according to claim 17.

19. and further comprising: when detecting that the temperature of at least one of the plurality of battery cells is equal to or higher than the preset temperature, cooling the at least one of the plurality of battery cells to a temperature lower than the preset temperature.

20. The method of thermal management of a battery system according to claim 17.

20. The step of transferring heat includes transferring heat until the temperature of the at least one of the battery cells reaches at least the predetermined temperature.

20. The method of thermal management of a battery system according to claim 17.

21. A battery system; a power control system (PCS) electrically coupled to the battery system; an electrical load electrically coupled to the power control system; Including, The battery system includes: a plurality of battery cells electrically connected to one another; a plurality of switches each connected to one of the plurality of battery cells; one or more heaters electrically coupled to the plurality of switches to actively or passively balance the state of charge (SoC) of the plurality of battery cells; a cooling unit that actively cools the heater to dissipate excess heat when the heater reaches a target temperature; Including, one or both of the power control system and the electrical load are electrically coupled to a grid; one or more of the battery system, the power control system, and the electrical load are insulated from one another by a thermal insulator; Energy storage systems.

22. A battery system; a power control system (PCS) electrically coupled to the battery system; an electrical load electrically coupled to the power control system; Including, The battery system includes: a plurality of battery cells electrically connected to one another; a plurality of switches each connected to one of the plurality of battery cells; one or more heaters electrically coupled to the plurality of switches to actively or passively balance the state of charge (SoC) of the plurality of battery cells; a cooling unit that actively cools the heater to dissipate excess heat when the heater reaches a target temperature; Including, the power control system and / or the electrical load are both thermally coupled to the battery system by one or more thermal conduits that transmit heat generated by the power control system and / or the electrical load to at least one of the battery cells; Energy storage systems.

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