Battery system for thermal management of battery cells

Abstract

This invention provides a battery system and a thermal management method for managing the thermal properties of battery cells. [Solution] The battery system includes a plurality of battery cells electrically connected to each other, a plurality of switches each connected to one of the plurality of battery cells, one or more heaters electrically connected to the plurality of switches to dissipate power from the plurality of battery cells, and one or more heat conduits that send the heat generated by the one or more heaters to at least one of the battery cells.

Description

[Technical Field]

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

[0002] As global warming progresses with 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 prepare for fluctuations due to the intermittent availability of such energy and to improve the stability of grid networks, the development of energy storage systems (ESS) is used to store surplus electricity, which can then be transmitted to end customers or the power grid when needed. In addition, electrochemical energy-based ESSs (e.g., rechargeable or secondary batteries) can provide cost-effective and clean forms of energy storage solutions. Examples of electrochemical energy storage systems include lithium-ion, lead-acid, sodium-sulfur, and redox-flow batteries. Different storage cycles 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. Factors that determine the suitability of the aforementioned electrochemical energy storage system for a specific application include investment costs, power, energy, lifespan, recyclability, efficiency, scalability, and maintenance costs. Competitive factors should be considered when selecting and designing an appropriate electrochemical storage system. [Overview of the project] [Means for solving the problem]

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

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

[0005] From a third perspective, a thermal management method for a battery system includes the step of sensing the state of charge (SoC) of each of a plurality of battery cells that are electrically connected to each other. The method further includes the step of dissipating power from one or more battery cells having an SoC above a set critical value via one or more heaters to generate heat by activating one or more switches connected to the plurality of battery cells. The method further includes the step of sending the heat generated from one or more heaters via one or more heat conduits to at least one of the plurality of battery cells. The battery system may be based on one or both of the first and second aspects.

[0006] From a fourth perspective, the energy storage system (ESS) includes a battery system comprising a plurality of battery cells electrically connected to each other, a plurality of switches each connected to one of the plurality of battery cells, and one or more resistors electrically connected to the plurality of battery cells to balance the charge state (SoC) of the battery cells actively or passively. The ESS further includes a power control system (PCS) electrically connected to the battery system. The ESS further includes an electrical load electrically connected to the PCS. Either or both of the PCS and the electrical load are electrically connected to the grid. In addition, one or more battery systems, PCS and electrical loads are insulated from each other by thermal insulation. The battery system may be based on either or both of the first and second perspectives.

[0007] From the fifth aspect, the energy storage system (ESS) includes a battery system comprising a plurality of battery cells electrically connected to each other, a plurality of switches each connected to one of the plurality of battery cells, and one or more resistors electrically connected to the switches to actively or passively balance the charge state (SoC) of the battery cells. The ESS further includes a power control system (PCS) electrically connected to the battery system. The ESS further includes an electrical load electrically connected to the power control unit. Either or both of the PCS and the electrical load are thermally connected to the battery system by one or more heat conduits that send the heat generated by either or both of the PCS and the electrical load to at least one of the battery cells. The battery system may be based on either or both of the first and second aspects. [Brief explanation of the drawing]

[0008] [Figure 1A] This diagram schematically shows an example of the charge state of an unmanaged battery cell. [Figure 1B] This diagram schematically shows an example of the charge state of a managed battery cell. [Figure 2A] This diagram schematically illustrates an example of an active balancing method for battery cells. [Figure 2B] It is a diagram schematically showing an example of a passive balancing method for battery cells. [Figure 3A] It is a diagram schematically showing an exemplary battery system including a plurality of battery cells electrically connected to a battery system. [Figure 3B] It is a diagram showing an exemplary battery management system embodied on a common substrate. [Figure 4A] It is a diagram schematically showing an exemplary energy storage system configured for a battery system according to an embodiment. [Figure 4B] It is a diagram schematically showing another exemplary energy storage system configured for a battery system according to an embodiment. [Figure 5A] It is a diagram schematically showing an exemplary battery system configured for thermal management of battery cells according to various embodiments. [Figure 5B] It is a diagram schematically showing an exemplary battery system configured for thermal management of battery cells according to various embodiments. [Figure 5C] It is a diagram schematically showing an exemplary battery system configured for thermal management of battery cells according to various embodiments. [Figure 5D] It is a diagram schematically showing an exemplary battery system configured for thermal management of battery cells according to various embodiments. [Figure 5E] It is a diagram schematically showing an exemplary battery system configured for thermal management of battery cells according to various embodiments. [Figure 6A] It is a flowchart showing a method for thermal management of a battery system according to an embodiment of the present invention. [Figure 6B] [[ID=3�]]It is a flowchart showing a method for thermal management of a battery system according to an embodiment of the present invention. [[ID=3Ą]] [Figure 7A] It is a diagram schematically showing an energy storage system configured for thermal management of battery cells according to various embodiments. [Figure 7B]A diagram schematically showing a battery system configured for thermal management of battery cells according to some embodiments. [Figure 7C] A diagram schematically showing a battery system configured for thermal management of battery cells according to some other embodiments. [Figure 7D] A diagram schematically showing an energy storage system configured for thermal management of battery cells according to various embodiments. [Figure 8A] A diagram schematically showing a redox battery cell that can be embodied as part of a battery and an energy storage system according to an embodiment. [Figure 8B] A diagram schematically showing a redox battery cell that can be embodied as part of a battery and an energy storage system according to an embodiment. [Figure 8C] A diagram schematically showing a redox battery cell that can be embodied as part of a battery and an energy storage system according to an embodiment. [Figure 8D] A diagram schematically showing a redox battery cell that can be embodied as part of a battery and an energy storage system according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and other objects and advantages will become apparent from the description of this specification. Inspecification. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration specific embodiments. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the disclosed embodiments. Thus, the accompanying drawings are shown for purposes of merely illustrating examples 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 light of the circumstances described above, one of the objectives of one or more aspects of some embodiments is to provide a thermal management method and battery system that improves the efficiency of electrochemical energy storage. A battery management system (BMS) means a control system that is electrically connected to a battery pack containing multiple battery cells and monitors the battery pack, including battery monitoring, providing battery protection, estimating the battery operating state, continuously optimizing battery performance, and communicating the operating state to an external device.

[0011] In some embodiments, the battery system includes a battery pack and a battery management system (BMS) connected thereto. The functions of the BMS include balancing multiple battery cells that may be electrically connected in series and / or parallel within the battery pack so that the battery cells within the battery pack are similar or actually reach the same state of charge (SoC).

[0012] From the perspective that the increased temperature accelerates the chemical reaction and allows the battery management system to generate heat while operating, in some other embodiments, the heat generated by the battery management system is recovered and efficiently sent to the battery cells to raise their temperature.

[0013] From the perspective that chemical reactions are accelerated at high temperatures, and that the battery management system can generate heat while operating, in the embodiments disclosed herein, the heat generated by the battery management system is recovered and efficiently sent to the battery cells to raise their temperature.

[0014] Figures 1a and 1b schematically show exemplary charge states for uncontrolled and controlled battery cells, respectively. Without a BMS, the damage to degraded battery cells can be accelerated by various processes. For example, during charging, a degraded battery cell may reach its charge limit prematurely due to a decrease in capacity. Even though a degraded battery cell has reached its charge limit, the entire battery pack may continue to charge. Such overcharging can further exacerbate the damage to already degraded battery cells and accelerate battery pack failure. Similarly, during discharge, a degraded battery cell may reach its discharge limit prematurely due to its low capacity. Even though a degraded battery cell has reached its discharge limit, the battery pack as a whole may continue to discharge. Such over-discharge can further damage battery cells that have already been degraded by over-discharge. Therefore, a BMS is necessary to balance the battery cells.

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

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

[0017] Passive balancing has several obvious disadvantages. For example, the energy waste can be harmful to the environment. Also, the heat generated by high balancing currents can have a fatal impact on battery cells. On the other hand, passive balancing has the advantages of being simple and low cost. Active balancing does not waste much energy and has obvious advantages, but it can also have disadvantages. For example, because it uses more electrical components, active balancing can be disadvantageous due to higher cost, lower reliability, and / or larger volume. Also, the standby current generated in active balancing can result in even greater power loss than in passive balancing.

[0018] Some battery cells lose capacity at low temperatures due to relatively slow chemical reaction rates that affect charging and discharging. 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 sub-zero charging. This plating not only causes permanent damage to the battery cell and reduces its capacity, but it can also make the battery cell more susceptible to failure when exposed to vibration or other stressors. On the other hand, lithium-ion battery cells can experience performance loss when operating at temperatures significantly higher than room temperature (e.g., above approximately 30°C). If lithium-ion battery cells are continuously charged and then recharged above this temperature, the performance loss can increase considerably (e.g., up to 50%). In particular, continuous exposure to overheating during rapid charge-discharge cycles can lead to premature aging and reduced battery life. For these reasons, a BMS (Battery Management System) is needed that can control the temperature of the battery pack by heating and cooling the battery cells.

[0019] Figure 3a schematically shows an exemplary battery system 10, which includes a plurality of battery cells 12-1, ... 12-(n-2), 12-(n-1), 12-n electrically connected to a battery management system (BMS) 14. Depending on the embodiment, the BMS 14 can function as a basic BMS that can embody 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 referred to as battery cells 12) are electrically connected to each other 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 referred to as switches 16) each connected 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 resistor 18) electrically connected to the switch 16, which dissipate power from the battery cells when one or more switches 16 are activated. The battery system 10 further includes a control unit 26 that senses the charge state (SoC) of the battery cells 12 and selectively activates one or more switches 16 based on the SoC. For example, when the SoC of one or more of the battery cells 12 is sensed to be higher than a critical value after being charged for a set period of time, for example by measuring the voltage of the battery cells, the control unit 26 can activate each of the switches 16 connected to one or more of the battery cells 12 and selectively dissipate excess charge from the battery cells using the respective connected resistors 18. The control unit 26 can extract excess charge from one or more battery cells 12 until one or more of the battery cells 12 have similar or actually the same SoC, for example, as shown in Figure 1b.

[0020] Figure 3b shows an exemplary battery management system 20 implemented on a common board. The battery management system 20 can represent a physical implementation of the BMS 14 shown in Figure 3a. Resistors 18, switches 16, and control units 26 are integrated on a common circuit board 22. The circuit board 22 includes terminals 24 for electrically connecting to multiple battery cells.

[0021] Figure 4a schematically shows an exemplary energy storage system (ESS) 30 configured for a battery system 10 (Figure 3a) according to an embodiment. The exemplary ESS 30 can, according to the embodiment, function as a base ESS including the battery system 10, which includes a BMS 14 (Figure 3a). The ESS 30 further includes a power control system (PCS) 32 electrically connected to a grid 34. The PCS 32 is electrically connected at its center to the battery system 10 and the electrical load 36. The PCS 32 is configured to receive power, for example, AC power. The PCS 32 is configured to receive power, for example, AC power from the grid 34 and control the power, for example, DC power, that is transmitted to the battery system 10 and the electrical load 36. The PCS 32 is further configured to control the transmission of power from the battery system 10 to the load 36. When configured in this way, the PCS 32 is configured to control the transmission 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] Figure 4b schematically shows another exemplary energy storage system (ESS) 30 configured for the battery system 10 (Figure 3a) according to an embodiment. The exemplary ESS 30 can, according to the embodiment, function as a base ESS including the battery system 10, which includes a BMS 14 (Figure 3a). The ESS 30 includes a power control system (PCS) 32 electrically connected to a grid 34. Similar to the ESS 30 shown in Figure 4a, in the shown ESS 30, the PCS 32 is electrically connected to the battery system 10 and the 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, that is transmitted to the battery system 10 and the load 36. However, unlike the ESS 30 shown in Figure 4a, both the PCS 32 and the electrical load 36 are connected to the grid.

[0023] Battery system for thermal management of battery cells As mentioned above, a battery management system (BMS) can be used to control the temperature of battery cells by heating and / or cooling. For heating, some battery systems can use an active heater to heat the battery cells. The active heater may be powered by an external power source, such as an AC power source, or by an internal power source, such as the battery pack of the battery system. For example, a thermal hydraulic system can be used as the active heater, which includes an electric heater that heats a fluid that is pumped and distributed throughout the battery pack. Some 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 acting as a load to heat the battery cells. In such battery systems, the BMS can be used to manage heat transfer from the heat source to the battery cells. However, existing heating technologies involve further energy consumption and / or heat that is not controlled by the battery system. Therefore, there is a need to provide a system and method that can control and efficiently provide heat from the battery cells themselves using a BMS that provides heat to the battery cells.

[0024] To address at least these requirements, the present invention discloses a battery system comprising a plurality of battery cells electrically connected to one of the battery cells. The battery system comprises a plurality of switches, each connected to one of the battery cells. The battery system further comprises one or more heaters electrically connected to the switches, which generate heat when activating one or more switches by dissipating power from the battery cells. The battery system further comprises one or more heat conduits that send the heat generated by the one or more heaters to at least one battery cell to raise its temperature.

[0025] Figures 5a to 5e schematically show exemplary battery systems 10 configured for thermal management of battery cells 12 in various embodiments. Each of the exemplary battery systems 10 shown includes a plurality of battery cells 12-1, ..., 12-(n-2), 12-(n-1), 12-n (hereinafter referred to as battery cells 12) and a battery management system (BMS) 14. The plurality of battery cells 12 are electrically connected to each other 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 referred to as switches 16) each connected to one of the battery cells 12. The battery system 10 further includes one or more heaters 17-1, ..., 17-(n-2), 17-(n-1), 17-n (hereinafter referred to as heaters 17) electrically connected to the switches 16 which act as effective heat sources. The battery system 10 may further include a control unit 26 that senses the charge state (SoC) of the battery cells 12 and selectively activates one or more switches 16 based on the SoC. A heater 17 is electrically connected to the switches 16 and generates heat when it activates the connected switches 16 by dissipating power from the battery cells 12. The heater 17 may include one or more common resistors, copper wires, nichrome wires, SMD resistors (surface mount resistors or chip resistors), an electric boiler, and a heat pump.

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

[0027] For example, after charging one or more battery cells 12 for a certain period of time by measuring the voltage of those cells, the control unit 26 can detect that the SoC is above a critical value and then activate one of the switches 16 connected to each of the batteries using the respective heaters 17 connected to each battery to selectively dissipate excess charge from the batteries. The control unit 26 can release excess charge from one or more battery cells 12 until they are similar or actually have the same SoC. Therefore, the heaters 17 not only heat the battery cells 12 but also perform a dual function of cell balancing.

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

[0029] According to various embodiments, the heat generated by one or more heaters 17 causes 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 into a part of the ESS 30, the battery cell 12 is heated to, for example, a range of about 20-30°C. If the battery cell 12 is a redox battery cell, for example a vanadium ion battery cell, the battery cell 12 can be heated to within 15-40°C.

[0030] If one or more heaters 17 have resistance values ​​within the range defined by 100mΩ to 100Ω, 200mΩ to 10Ω, 500mΩ to 1Ω, or any of these values, then they can simultaneously function as both a cell balancing resistor 18 and an effective heat source.

[0031] Furthermore, referring to Figures 5a to 5e together, the heat conduit 19 may include any suitable heat conducting medium to efficiently conduct heat from the heater 17 to the battery cell 12. In some embodiments, the heat conduit 19 includes an air conduit that carries heat by convection. In other embodiments, the heat conduit includes a heat conducting pipe that carries heat by conduction.

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

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

[0034] Figure 5b schematically shows an exemplary battery system 10 configured for thermal management of the battery cells 12 in some other embodiments. In the shown battery system 10, each battery cell 12 is connected to a dedicated heater 17 by a dedicated conduit 19. However, unlike the battery system 10 shown in Figure 5a, in these embodiments, each heater 17 is physically positioned closer to the dedicated battery cell 12 than to the dedicated switch 16. In the shown arrangement, the switch 16 and control unit 26 are integrated as part of the BMS 14, while the heaters 17 may be formed outside the BMS 14 and integrated, for example, as part of a battery pack.

[0035] In the battery system 10 described in Figures 5a and 5b, a dedicated heater 17 is provided for each battery cell 12. However, the 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, a single central heater 17 may be configured to deliver heat to each battery cell 12, as described herein.

[0036] Figure 5c schematically shows 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, for example, a single P2H element, are electrically connected to a plurality of switches 16, each connected to a battery cell 12 at the center. The single heater 17 dissipates power from the battery cell 12 when one or more switches 16 are activated. The single heater 17 may consist of a plurality of resistors 18 mounted on a single circuit board. The single heater 17 is thermally connected at the center to the plurality of battery cells 12 via one or more heat conduits 19, for example, dedicated heat conduits. As shown in Figure 5b, the switches 16 and control unit 26 are integrated as part of the BMS 14, while the heater 17 may be formed outside the BMS 14, for example, integrated as part of a battery pack.

[0037] Figure 5d schematically shows 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, for example, a single P2H element, are wirelessly connected to a plurality of switches 16, each connected to a battery cell 12. The wireless connection is configured to wirelessly activate the heaters 17 by communicatively connecting them via one or more switches 16. In a manner similar to the battery system in Figure 5c, a single heater 17 is sequentially thermally connected to a plurality of battery cells 12 at the center via one or more heat conduits 19, for example, dedicated heat conduits. Similar to the battery system 10 shown in Figure 5b, the switches 16 and control unit 26 are integrated as part of the BMS 14, while the heaters may be formed outside the BMS, for example, integrated as part of a battery pack.

[0038] In Figures 5a to 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 so that one or more heaters 17 are actively cooled, for example, to prevent overheating.

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

[0040] Thermal management methods for battery systems Figure 6a is a flowchart illustrating a thermal management method for a battery system 10 according to one embodiment. Figure 6b is a flowchart illustrating a thermal management method for a battery system 10 according to another embodiment. According to various embodiments, a thermal management method for a battery system 10 includes a step 40 of sensing the state of charge (SoC) of a plurality of battery cells that are electrically connected to each other. The method further includes a step 41 of dissipating power from one or more battery cells that have an SoC above a critical value already set by one or more heaters to generate heat, by activating one or more switches connected to the battery cells. The method further includes a step 42 of sending the heat generated by one or more heaters to at least one battery cell via one or more heat conduits to raise the temperature by at least 5°C. The thermal management method can be embodied in any battery system 10 disclosed herein.

[0041] Referring to Figure 6a, the above method includes step 40 of sensing the charge state (SoC) of each of a plurality of battery cells that are electrically connected to one another.

[0042] In some embodiments, as shown in Figure 6a, the battery cells may be charged and discharged before the SoC of each battery cell is detected 40, as shown in step 50 of Figure 6b. The control unit 26 (Figures 5a to 5e) can detect the SoC of each battery cell 12.

[0043] Referring to Figure 6b, in some embodiments, the step of sensing the SoC of each battery cell includes a step of measuring or sensing the cell voltage of each battery cell, as shown in step 51. The control unit can measure the cell voltage of each battery cell.

[0044] In some embodiments, the method further includes a step in step 52 in which the control unit determines whether the average of the cell voltages has reached a target voltage from the measured cell voltages of the battery cells before proceeding. The control unit 26 can determine from the measurement of the cell voltages of the battery cells that the average of the cell voltages has reached a target voltage before proceeding. If the control unit detects in step 52 that one or more battery cells have an SoC that exceeds a set critical value, for example, as indicated by the battery cell voltage, the method can apply a cell balancing scheme to balance the battery cells. On the other hand, if the control unit detects in step 52 that there are no cells with an SoC or cell voltage that exceeds a set critical value, the method can return to step 50 to charge or discharge the battery cells. For example, the target voltage for charging and discharging may be a value within a range defined by approximately 1.0V, 1.5V, 2.0V, 2.5V, 3.0V, or any value among these, for example, approximately 1.2V.

[0045] Referring further to Figure 6b, after charging and discharging in step 50 and determining that the average cell voltage has reached the target voltage in step 52, the method proceeds to the step of determining whether to trigger the cell balancing method in step 53 and / or whether to heat the battery cell in step 57. The control unit 26 can determine whether to trigger the cell balancing method in step 53 and / or whether to heat the battery cell in step 57. For example, an abnormal parameter may be a relatively high range of SoC or cell voltage. For example, an abnormal parameter may be a relatively high range of SoC or cell voltage. In this example, if the range of SoC or cell voltage measured from the battery cell 12 is determined to be outside the already set range, the cell balancing method may be triggered. For example, if the cell voltage range exceeds 20mV, 40mV, 60mV, 80mV, 100mV, or any value defined by any of these values, for example, 50mV, the above method triggers the cell balancing mechanism in step 53 in some embodiments, as shown in Figure 6b. That is, the control unit measures the cell voltage in step 51 to sense the SoC, and if it measures a cell voltage range of approximately 50mV or more, it can selectively activate one or more switches.

[0046] Referring further to Figure 6a, the method further includes step 41, after sensing the SoC, dissipating power from one or more battery cells having an SoC above a set critical value via one or more heaters to generate heat by activating one or more switches 16 connected to the battery cell 12. The control unit 26 can dissipate power from one or more battery cells 12. Dissipation of power may occur when triggering the cell balancing scheme. For example, the cell balancing scheme by step 53 shown in Figure 6b can be configured to selectively dissipate power from battery cells having an SoC higher than a set value, for example, a cell voltage higher than a set value. For example, the set value may be the average cell voltage. For example, if the target charge / discharge voltage is 1.2V, the switches 16 corresponding to battery cells with a cell voltage greater than 1.2V are activated to trigger the cell balancing scheme in step 53. That is, as shown in Figure 6b, the control unit 26 senses the SoC by measuring the cell voltage in step 51 and selectively activates one or more switches when it measures an average cell voltage greater than approximately 1.2V.

[0047] Referring further to Figure 6a, in relation to power dissipation, the method further includes step 42 of sending heat generated from one or more heaters 17 to at least one of the battery cells 12 via one or more heat conduits 19 to raise the temperature by at least 5°C. In some embodiments, a temperature control loop may be initiated to sense the temperature of the battery cells, as shown in step 54 of Figure 6b, in order to determine whether or not the battery cells 12 should be heated, as shown in step 55 of Figure 6b, before sending the heat. In these embodiments, the method further includes a step of measuring the temperature of at least one of the battery cells before sending the heat. The temperature of the battery cells 12 can be measured using one or more temperature sensors 13 positioned adjacent to one or more battery cells 12.

[0048] If the temperature measured in step 55 is determined to exceed an already set value, the method may cool the battery cell to a temperature lower than the already set temperature, as shown in step 56 of Figure 6b, instead of activating the switch to heat the battery cell. In this case, the method returns to step 50, which is the starting part of the method shown in Figure 6b.

[0049] On the other hand, if it is determined that the temperature measured in step 55 does not exceed a previously set value, the above method is carried out by supplying heat in step 57 of Figure 6b. According to the embodiment, the previously set temperature may be a value 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 in the range of, for example, 20 to 30°C. If the battery cell is a redox battery cell, for example, a vanadium ion battery cell, the battery cell may be heated within 15 to 40°C.

[0050] Once the battery cell has been heated to the set temperature, or after heating has started in step 57, the method proceeds to charge and discharge the battery cell in step 50, as shown in Figure 6b.

[0051] Energy storage system for thermal management of battery cells According to the various embodiments described above, thermal management of the battery cells 12 of the battery system 10 can be performed using one or more heaters 17 electrically configured to generate heat by dissipating power from the battery cells 12 during activation, and one or more heat conduits 19 that further deliver 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, further or alternative thermal management features can be realized as described herein.

[0052] Figure 7a schematically shows an energy storage system 30 configured for thermal management of the battery cell 12 in various embodiments. The shown ESS 30 may include the same features as described above for Figure 4b, and for simplicity, a detailed explanation is omitted here. It can be seen that in other embodiments, the ESS 30 can be configured in the same manner as shown in Figure 4a. The shown PCS 32 is electrically connected to the battery system 10 and the load 36. In the same manner as the ESS 30 described above for Figure 4b, the PCS 30 is configured to receive power, for example AC power, from the grid 34 and control the power, for example DC power, that is transmitted to the battery system 10 and the load 36.

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

[0054] In some embodiments, one or both of the PCS32 and the electrical load 36 are configured to be electrically connected to the grid 34. Furthermore, one or more of the battery system 10, PCS32, and electrical load 36 are insulated by air, as well as by a thermal insulator 38. The thermal insulator 38 may include, but are not limited to, some polymer materials such as polypropylene, polyester, or polyimide, paper-based materials, or glass-based materials. The thermal insulator 38 recovers the heat generated by the PCS32 to heat the battery cells 12. The thermal insulator 38 improves heat storage for efficient and rapid heating of the battery cells 12 using any of the described battery system 10 configurations. For this purpose, the inventors have found that the insulator 38 has a thermal conductivity within a defined range of 0.01-0.2, 0.2-0.4, 0.4-0.6, 0.8-1 W / m·K, or any value among these. Therefore, as shown, the thermal insulation material 38 can provide a partially or completely thermally sealed ESS 30 for effective heating of the battery cell 12.

[0055] In the shown embodiment, the battery system 10 and PCS 32 are insulated by air and an insulating material 38. However, the embodiment is not limited to this, and in other embodiments, one or more of the battery system 10, PCS 32, and electrical load 36 may be insulated from each other by air and an insulating material 38. For example, in some embodiments, the battery system 10, PCS 32, and electrical load 36 may all be insulated by an insulating material 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, a BMS 14, a 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, the 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 as part of a thermally enclosed ESS system 30.

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

[0058] Figure 7b schematically shows a battery system 10 configured for thermal management of battery cells in some embodiments. In the shown embodiments, the battery cells 12 and one or more heaters 17 are encapsulated in an insulating material 38. For example, the battery rack housing the battery cells 12 may be insulated, and the battery cells 12 and heaters 17 may be housed inside it.

[0059] Figure 7c schematically shows a battery system 10 configured for thermal management of the battery cells 12, as in some other embodiments. In the shown embodiment, the battery cells 12 and one or more heaters 17 are encapsulated in a thermal insulator 38 in a manner similar to that shown in the embodiment in Figure 7b. In the shown embodiment, the BMS 14, including the switch 16 and control unit 26, is also encapsulated. For example, a battery rack housing the battery cells 12 can be insulated and can house the battery cells 12, heaters 17, and BMS 14 inside.

[0060] Figure 7d schematically shows an energy storage system 30 configured for thermal management of the battery cell 12 in various other embodiments. The shown ESS may include the same features as described above for Figures 4b and 7a, and for simplicity, a detailed explanation is omitted here. However, it can be seen that in other embodiments, the ESS 30 can be configured in a manner similar to that shown in Figure 4a.

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

[0062] In various embodiments, the heat conduit 19 may include any suitable heat conductive medium to efficiently conduct heat from the PCS 32 and / or electrical load 36 to the battery cell 12. In some embodiments, the heat conduit 19 includes an air conduit that conducts heat by convection. The air conduit may include, for example, a tubular conduit that carries heated air and is at least partially sealed. In other embodiments, the heat conduit 19 includes a heat conduction pipe that carries heat by conduction. The heat conduction pipe may include a solid or hollow pipe filled with a heat conductive medium, such as a metal or other solid heat conductive material. In yet another embodiment, the heat conduit 19 includes a heat conduction pipe or conduit that carries heat by a combination of conduction and convection. The heat conduction pipe may include a hollow pipe filled with a heat conductive medium, such as a liquid that is heated by conduction by one or both of the PCS 32 and the electrical load 36, and then the heated liquid is transported to the battery cell 12 by convection.

[0063] Referring further to Figure 7d, in the shown embodiment, the battery system 10 is insulated, while the PCS 32 and electrical load 36 are not. However, the shown configuration is illustrative only, 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 each other by a non-air insulating material 38, as described above with respect to Figure 7a.

[0064] Furthermore, 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, switches 16, one or more heaters 17, and one or more heat conduits 19 of the battery system 10 described above can be encapsulated with an insulating material 38 other than air. Figures 7a and 7b show two exemplary embodiments.

[0065] Redox battery system with thermal management function As mentioned above, other competitive factors to consider 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 the various electrochemical energy storage systems, redox batteries (RBs) appear to be preferred for stationary energy storage. An RB is an electrochemical energy conversion device that utilizes the redox process of redox species dissolved in a solution. Some preferred features of RBs include 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 time, making RBs suitable for storing electricity generated from renewable resources.

[0066] From the perspective of the battery systems disclosed herein, RB may be particularly suitable for various embodiments of the battery systems, thermal management methods, and energy storage systems disclosed herein. One such advantage arises from the fact that the redox chemical reactions that influence the charging and discharging of redox batteries can be accelerated at elevated temperatures, for example, by Arrhenius behavior. While obtaining such advantages, the risk of overheating and / or explosion is relatively lower in RB compared to lithium-ion batteries, so RB may be particularly suitable for the implementation of various embodiments of thermal management disclosed herein.

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

[0068] Unlike conventional redox batteries, 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 sealed within a case or frame 212. The sealed case 212 prevents its internal contents from being physically accessible from the outside during normal operation. That is, the positive and negative electrode electrolytes do not have fluid communication with an external container such as an electrolyte tank. The casing 212 completely and / or permanently seals the redox battery 200A. This configuration, in contrast to conventional redox flow batteries, means that the redox battery cell has fluid communication with an external tank. That is, in a redox battery, neither the positive electrode electrolyte storage 106A nor the negative electrode electrolyte storage 106B of the enclosed cell has fluid communication with or is physically connected to a separate electrolyte tank storing the first or second electrolyte, respectively. Thus, the substantial total volume of the positive and negative electrode electrolytes is stored within the redox battery and sealed and enclosed by the casing 212. Specifically, the first electrolyte storage 106A stores the substantial total volume of the first electrolyte for the first half cell 204A, and the second electrolyte storage 106B stores the substantial total volume of the second electrolyte for the second half cell 204B. Partially because the redox battery 200A is not connected to a separate storage tank, the redox battery 200A preferably does not include conduits for transferring electrolyte to and from the battery cells, or pumps for circulating the electrolyte.

[0069] As mentioned above, 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, the first and second electrolytes circulate 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, respectively. In various configurations, the self-circulation of the first and second electrolytes is caused by one or more of the following: osmotic pressure difference between the first and second electrolyte reservoirs; density changes of 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 to the respective first and second electrodes; redox half-reactions of the first and second electrolytes; and thermal expansion or contraction of one or both of the first and second electrolytes. The inventors have found that if the thickness of the positive and negative electrode electrolyte storage units 106A and 106B in the cross-sectional view of Figure 8a does not exceed a value within the range defined by 20 cm, 15 cm, 10 cm, 5 cm, 2 cm, 1 cm, or any of these values, then self-circulation is effective in providing stability of power and energy output.

[0070] Referring to Figure 8a, the casing 212 is formed of a suitable corrosion-resistant material to accommodate the positive and negative electrode electrolytes, which may 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 according to the embodiment may be formed of a flexible material that deforms to accommodate changes in internal pressure within the positive and negative electrode electrolyte storage units 106A, 106B. Increases in internal pressure can be caused, for example, by various effects described later for a pressure-regulated redox battery. In a configuration in which only the portion of the casing is formed of a flexible material, the remainder can be formed of a rigid material. The flexible portion can be configured to expand with increasing pressure, for example, to accommodate increases in volume of either or both of the positive and negative electrode electrolyte storage units 106A, 106B by more than 0.1%, 0.2%, 0.5%, 1%, 2%, 5%, 10%, 20%, and 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 oxidation-reduction battery 200A configured in this way offers various technical and commercial advantages. For example, various reliability errors associated with conduits between the battery cells and the tank, such as pipe joints, as well as pumps for circulating the electrolyte, are effectively reduced or eliminated, thereby reducing unplanned repairs as well as safety hazards and operating costs associated with the operation of the oxidation-reduction 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 inventors have made it possible to improve the power density of the oxidation-reduction battery 200A by up to 2 to 50 times compared to conventional RFBs, depending on the size of the system. As mentioned above, power density indicates the power or energy output of the energy storage device relative to the total volume of the energy storage device. Therefore, in the case of an oxidation-reduction battery, the power or energy density indicates the ratio of power or output to the total volume of the oxidation-reduction battery. Furthermore, space efficiency is further improved by omitting a separate circulation system including tanks, pumps, and conduits. Moreover, the system complexity is greatly reduced, significantly lowering the barriers to the commercial implementation of the redox battery 200A. For example, unlike conventional RFBs, the redox battery 200A is manufactured in packs similar to lithium-ion batteries for modular implementation, eliminating the need for the embedded structure required for installing conventional RFBs, making it more suitable for automation and mass production.

[0072] In the following, the operating principle and aspects of the 200A redox battery will be explained using an example of a vanadium redox battery based on a vanadium (V)-based redox pair. However, the examples are not limited to this, and it can be understood that the principle described in this application can be applied to various other redox batteries with different redox pairs.

[0073] In the V oxidation-reduction battery according to the example, the first oxidation-reduction pair dissolved in the first or positive electrode electrolyte of the first half cell 204A is V 4+ / V 5+It may be a redox pair, and the second redox pair dissolved in the second or negative electrode electrolyte of the second half-cell 204B is V 2+ / V 3+ It may also be a redox pair. The redox reaction during charge and discharge can be explained using the following mathematical formula, 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 reaction: V 2+ +V 5+ ←→V 3+ +V 4+

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

[0075] Other redox reactions can be embodied in the 200A redox battery according to the examples. In various examples, the first and second redox pairs contain one or more ions from vanadium (V), zinc (Zn), bromine (Br), chromium (Cr), manganese (Mn), titanium (Ti), iron (Fe), cerium (Ce), and cobalt (Co). In some examples, the first and second redox pairs contain the same metal ions, as in the V redox battery described above. In these examples, cross-contamination of the electrolytes is preferably avoided by mixing the positive and negative electrode electrolytes.

[0076] As mentioned above, the electrolyte of a redox battery is a solution that conducts electric current through ionization. The electrolyte supports the reduced and oxidized forms of the redox pair, as well as the cations and anions, in order to balance the charge of the ions in the solution during the oxidation and reduction of the redox pair. The positive and negative electrode electrolytes in the examples contain acidic aqueous solutions. 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 reduce the volume of the positive and negative electrode electrolyte storage 10⁶A,10⁶B required for a given amount of energy and power output. However, very high concentrations of V ions can reduce the stability of the V ions. Therefore, 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 the range defined by 1.0 M, 1.5 M, 2.0 M, 2.5 M, or any of these values. On the other hand, V ion concentrations lower than 1.0 M may result in energy levels that are not suitable for the application. On the other hand, V ion concentrations greater than 2.5 M are, for example, V at operating temperatures above 50°C. 5+ The ion stability may be even lower; for example, at operating temperatures below -20°C, the V of the electrolyte may be lower. 2+ and V 3+ The solubility limit of ions can be reached.

[0077] Preferably, according to the examples, the positive and negative electrode electrolytes may contain the same solvent and / or ions of the same metal. In such examples, the mixing of the positive and negative electrode electrolytes by the ion exchange membrane 112 prevents contamination of each half cell. Furthermore, the positive and negative electrode electrolytes can be prepared from the same starting solvent and solute. For example, in the case of a V oxidation-reduction battery according to some examples, both the positive and negative electrode electrolytes contain sulfuric acid. Tetravalent vanadium ions (V 4+ ) and / or trivalent vanadium ions (V 3+ To form the positive electrode electrolyte, for example, 0.1 M to 2.5 MVOSO4 (vanadyl sulfate) can be dissolved in 0.1 M to 6 M H2SO4 in an aqueous solution to provide an electrolyte. The tetravalent / trivalent vanadium ions are electrochemically oxidized to form the positive electrode electrolyte (negative electrode solution), which is composed of pentavalent vanadium ions (V 5+ This is a solution of ). Conversely, the tetravalent / trivalent vanadium ions are electrochemically reduced to form a negative electrode electrolyte (positive electrode solution), which is a solution of divalent vanadium ions (V 2+ It is a solution of ).

[0078] Referring to Figure 8a, in various embodiments, the positive and negative electrodes, respectively, located in the positive and negative electrode electrolyte storage units 106A and 106B, include, for example, carbon or graphite felt, carbon cloth, carbon black, graphite powder, and graphene carbon-based materials. 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 a 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 surface of the electrodes may be modified, for example, by coating with a metal to increase surface roughness or by doping with additives.

[0079] If positive and negative electrode electrolyte storage units 106A and 106B that define the reaction space exist, the spaces between the ion exchange membrane 112 and the first and second positive electrode plates 208A and 208B, respectively, and between the ion exchange membrane 112 and the positive and negative electrode current collectors 108A and 108B, respectively, are partially or completely filled with each electrode. After being filled with each electrode, if the remaining space of the positive and negative electrode electrolyte storage units 106A and 106B exists, the spaces between the ion exchange membrane 112 and the first and second positive electrode plates 208A and 208B, respectively, and between the ion exchange membrane 112 and the positive and negative electrode current collectors 108A and 108B, respectively, are partially or completely filled with each electrolyte. In various embodiments, except when holes are intentionally perforated or the membrane becomes porous, as will be described later, the ion exchange membrane 112 substantially separates the two half-cells, substantially preventing the mixing of the two electrolytes and redox pairs, and balances the charge between the two half-cells in order to complete the circuit while current flows. + This enables the transport of ions such as [specific ions]. The ion exchange membrane 112 may be an anion exchange membrane or a cation exchange membrane. The ion exchange membrane 112 may contain materials from several categories, 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] The various embodiments shown include, but are not limited to, an ion exchange membrane 112 that may be selective for a particular ion type, such as anions or cations. For example, in various embodiments, the ion exchange membrane 112 may be a non-selective membrane, such as a porous membrane.

[0081] Referring to Figure 8a, in some embodiments, the output power can be extended by connecting many single redox battery cells in series, for example, to form a cell stack. In such a configuration, the first and second positive plates 208A, 208B facilitate the series connection of single cells and eliminate the current collector plates 108A, 108B between adjacent positive plates. The first and second positive plates 208A, 208B are formed from suitable materials such as graphite, carbon, or carbon plastic, providing high electrical conductivity and low internal resistance to the cell stack. Furthermore, the first and second positive plates 208A, 208B support the contact pressure they receive when pressed against the electrodes to increase electrical conductivity. Moreover, the first and second positive plates 208A, 208B are provided to have high acid resistance to prevent corrosion and oxidation of the current collector plates 108A, 108B.

[0082] The positive and negative electrode current collectors 108A and 108B contain metals with high electrical conductivity, such as copper and aluminum, and function to conduct electric current during the charging and discharging process.

[0083] As mentioned above, a single 200A oxidation-reduction battery has an output voltage characterized by electrochemical reactions of approximately 1.65V or less. Therefore, additional cells can be electrically connected in series or parallel to achieve even higher voltages and currents, as previously described.

[0084] Figure 8b is a schematic diagram of a redox battery, in some embodiments, which includes a plurality of sealed redox battery cells in a stacked configuration. The shown redox battery 200B includes a plurality of stackable battery cells 200B-1, 200B-2, ..., 200B-n, each cell configured in a similar manner to the redox battery 200A (Figure 2a) (Figure 8a). Each of the plurality of 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 shown embodiments, each of the plurality of battery cells 200B-1, 200B-2, ..., 200B-n is enclosed separately by a casing 212. The plurality of battery cells 200B-1, 200B-2, ..., 200B-n are electrically connected in series to increase the output voltage.

[0085] Figure 8c is a schematic diagram of a redox battery comprising multiple redox battery cells in a stacked configuration, as in some other embodiments. The shown redox battery 200C comprises multiple stackable battery cells 200C-1, 200C-2, ..., 200C-n, each of which is configured in a manner similar to redox battery 200A (Figure 8a), including a positive electrode electrolyte reservoir 106A, a negative electrode electrolyte reservoir 106B, and an ion exchange membrane 112. However, unlike redox battery 200B (Figure 8B), in the shown embodiment, the multiple battery cells 200C-1, 200C-2, ..., 200C-n are surrounded by a common casing 222. Similar to the oxidation-reduction battery 200B (Figure 8b), multiple battery cells 200C-1, 200C-2, ..., 200C-n are electrically connected in series to increase the output voltage. In some embodiments, the positive electrode electrolyte storage cells 106A of multiple battery cells 200C-1, 200C-2, ..., 200C-n can be fluidically communicated with each other, and the negative electrode electrolyte storage cells 106B of multiple battery cells 200C-1, 200C-2, ..., 200C-n can be fluidically communicated with each other. The oxidation-reduction battery 200C can be composed of a pouch-type battery or a rigid-case-type battery.

[0086] Figure 8d is a schematic diagram of an oxidation-reduction battery, according to an embodiment, which includes a plurality of oxidation-reduction battery cells in a cylindrical stacked configuration. The shown oxidation-reduction battery 200D includes a plurality of battery cells 200D-1, 200D-2, ..., 200D-n that can be stacked in a cylindrical shape, and each of the plurality of battery cells 200D-1, 200D-2, ..., 200D-n is configured in the same manner as oxidation-reduction battery 200A (Figure 8a), which includes a positive electrode electrolyte storage 106A, a negative electrode electrolyte storage 106B, and an ion exchange membrane 112. The plurality of battery cells 200D-1, 200D-2, ..., 200C-n may be individually enclosed in a casing in the same manner as described above for oxidation-reduction battery 200B (Figure 8b). Alternatively, multiple battery cells 200D-1, 200D-2, ..., 200C-n may be surrounded by a common casing 222 in the same manner as described above for the redox battery 200C (Figure 8c). In the same manner as for the redox battery 200B (Figure 8b), multiple battery cells 200D-1, 200D-2, ..., 200D-n are electrically connected in series to increase the output voltage. In some embodiments, the positive electrode electrolyte storage cells 106A of multiple battery cells 200D-1, 200D-2, ..., 200D-n can be fluidically communicated with each other, and the negative electrode electrolyte storage cells 106B of multiple battery cells 200D-1, 200D-2, ..., 200D-n can be fluidically communicated with each other.

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

[0088] Further examples 1. 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 and configured to generate heat when activating one or more of the switches by dissipating power from the battery cells, wherein one or more heat conduits are configured to send the heat generated by the one or more heaters to at least one of the battery cells to raise its temperature.

[0089] 2. 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 and configured to generate heat when one or more switches are activated by dissipating power from the battery cells, wherein the heaters are configured to act as one or more resistors to actively or passively balance the charge state (SoC) of the battery cells and raise the temperature of the battery cells by the heat.

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

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

[0092] 5. Any of the battery systems in Examples 1 to 4 has a plurality of battery cells that are oxidation-reduction cells.

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

[0094] 7. The battery system of Embodiment 6 has a control unit configured to selectively activate one or more switches connected to the battery cell when it senses that the SoC has moved outside a previously set range.

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

[0096] 9. Any of the battery systems in Examples 6 to 8 senses the charge state (SoC) by measuring the cell voltage and has a control unit configured to selectively activate one or more switches when measuring an average cell voltage greater than approximately 1.2V.

[0097] 10. Any of the battery systems in Examples 6 to 9 has a control unit configured to sense the charge state (SoC) by measuring the cell voltage and to selectively activate one or more switches when measuring a cell voltage range greater than approximately 50 mV.

[0098] 11. Any of the battery systems in Examples 1 to 10 further includes a plurality of temperature sensors, each configured to measure the temperature of at least one of the battery cells.

[0099] 12. Any of the battery systems in Examples 6 to 9 has a control unit configured to activate one or more switches when it is determined that the temperature of at least one of the battery cells is lower than a previously set temperature.

[0100] 13. Any of the battery systems in Examples 6 to 10 has a control unit configured to activate one or more switches after cooling at least one of the battery cells to a temperature lower than a previously set temperature.

[0101] 14. Any of the battery systems in Examples 6 to 11 has a control unit configured to deactivate any of the above switches that have been activated when it senses that the temperature of at least one of the battery cells has increased by at least 5°C.

[0102] 15. Any of the battery systems in Examples 1 to 14 uses heat generated by one or more heaters to raise the temperature of at least one of the battery cells to 20 to 30°C.

[0103] 16. Any of the battery systems in Examples 1 to 15 has a heat conduit that includes an air conduit that delivers the heat by convection.

[0104] 17. Any of the battery systems in Examples 1 to 16 has a heat conduit including a heat conduction pipe that transmits the heat by conduction.

[0105] 18. Any of the battery systems in Examples 1 to 17 utilizes the heat generated by dissipating power from the battery cell to which power is supplied.

[0106] 19. Any of the battery systems in Examples 1 to 17 uses the heat generated by dissipating power from the battery cells, which is then sent to different battery cells among the battery cells.

[0107] 20. In any of the battery systems of Examples 1 to 19, each of the battery cells is a redox battery cell, the redox battery cell comprising: a first half-cell containing a first electrolyte in which a first redox pair configured to undergo a first redox half-reaction is dissolved; a second half-cell containing a second electrolyte in which a second redox pair configured to undergo a second redox half-reaction is dissolved; and an ion exchange membrane separating a positive electrode electrolyte storage area and a negative electrode electrolyte storage area, 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 pair or the second redox pair, which contains one or more ions from 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 oxidation-reduction pairs containing V ions.

[0110] 23. Any of the battery systems in Examples 1 to 22 is a redox battery cell comprising a redox flow battery cell, which includes a separate tank for storing the first electrolyte and the second electrolyte outside the battery cell.

[0111] 24. Each of the battery cells in any of the battery systems in Examples 1 to 23 is connected to a dedicated heater among the heaters by a dedicated conduit among the conduits.

[0112] 25. In the battery system of Example 24, each heater is physically positioned closer to the dedicated switch than to the dedicated battery cell among the battery cells.

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

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

[0115] 28. In the battery system of Example 24, each heater is physically positioned closer to the dedicated battery cell than to the dedicated switch among the switches.

[0116] 29. Any of the battery systems in Examples 1 to 23 further includes a central heater that is electrically connected at the center to a plurality of switches, the central heater being thermally connected at the center to a plurality of battery cells via one or more heat conduits.

[0117] 30. Any of the battery systems in Examples 1 to 23 has a central heater which is wirelessly connected to the plurality of switches in the center and thermally connected to the plurality of battery cells in the center via one or more heat conduits.

[0118] 31. The battery system of Example 29 or 30 has the central heater which is a single heater.

[0119] 32. Any of the battery systems in Examples 1 to 31 has a heater configured to actively cool to dissipate overheating when it reaches a target temperature.

[0120] 33. Any of the battery systems in Examples 1 to 32 has one or more heaters having a resistance of 100 mΩ to 100 Ω.

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

[0122] 35. The battery system of Example 34 comprises each of the battery cells encapsulated in a thermal insulator, one or more of the heaters, and one or more of the heat conduits.

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

[0124] 37. Any of the battery systems in Examples 34 to 36 has a thermal insulator having a thermal conductivity of 0.01 to 1 W / m·K.

[0125] 38. Any of the battery systems in Examples 1 to 37 is electrically connected to one or both of an external power control system and an external electrical load, and the external power control system and the external electrical load are thermally connected to the battery system by an external heat conduit configured to send the 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 raise its temperature.

[0126] 39. Any of the battery systems in Examples 1 to 38 has one or more heaters having a resistance of 100 mΩ to 100 Ω.

[0127] 40. A thermal management method for a battery system includes the steps of: sensing the charge state (SoC) of each of a plurality of battery cells electrically connected to each other; activating one or more switches connected to the battery cells to dissipate power from one or more of the battery cells having an SoC above a set critical value by one or more heaters to generate heat; and sending the heat generated from one or more heaters via one or more heat conduits to at least one of the battery cells to raise the temperature of the at least one.

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

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

[0130] 43. Any of the methods in Examples 40 to 42 further includes the step of 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. In any of the methods in Examples 40 to 43, the step of sensing the SoC includes a step of measuring the cell voltage, wherein the already set critical value of the SoC corresponds to the average cell voltage.

[0132] 45. Any of the methods in Examples 40 to 44 further includes the step of activating a cell balancing method based on the sensed SoC.

[0133] 46. ​​In the method of Example 45, the step of activating the cell balancing method is activated when it is determined that the cell voltage range exceeds a previously set value of approximately 50 mV.

[0134] 47. The method of Example 46 further includes the step of selectively activating one or more switches connected to one or more battery cells having an SoC greater than or equal to the already set critical value when the range of the cell voltage exceeds the already set value.

[0135] 48. Any of the methods in Examples 40 to 46 further includes the step of sensing the temperature of at least one of the battery cells before delivering the heat.

[0136] 49. In the method of Example 48, the step of supplying heat includes a step of supplying heat when it is detected that the temperature of at least one of the battery cells is below a set temperature.

[0137] 50. When the method of Embodiment 48 senses that the temperature of at least one of the battery cells is above the previously set temperature, the method further includes the step of cooling at least one of the battery cells to below the previously set temperature.

[0138] 51. In the method of Example 48 or 49, the step of supplying heat includes supplying heat until the temperature of at least one of the battery cells reaches at least the already set temperature.

[0139] 52. In any of the methods of Examples 48 to 51, the battery cell includes a lithium-ion battery cell, and the previously set temperature is 20 to 30°C.

[0140] 53. In any of the methods of Examples 48 to 52, each of the battery cells includes an oxidation-reduction battery cell, and the previously set temperature in any of the methods of Examples 48 to 52 is 30 to 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 to actively or passively balance the charge state (SoC) of the battery cells, and either or both of the PCS and the electrical load are configured to be electrically connected to a grid, and one or more of the 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 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 to actively or passively balance the charge state (SoC) of the battery cells, and either or both of the PCS and the electrical load are thermally connected to the battery system by one or more heat conduits configured to send heat generated by either or both of the PCS and the electrical load to at least one of the battery cells to raise its temperature.

[0143] 56. 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 resistors electrically connected to the switches to balance the charge state (SoC) of the battery cells actively or passively, and the battery system is according to any of Examples 1 to 37.

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

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

[0146] 59. The ESS of Example 55 comprises one or more of the battery systems, the PCS and the electrical loads, which are insulated from each other by an insulating material having a thermal conductivity of 0.01 to 1 W / m·K other than air.

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

[0148] 61. The ESS of Example 56 comprises one or more of the battery systems, the PCS and the electrical loads, which are insulated from each other by an insulating material having a thermal conductivity of 0.01 to 1 W / m·K, other than air.

[0149] 62. The ESS of Example 56 has one or both of the PCS and the electrical loads thermally connected to the battery cells by one or more heat conduits configured to send heat generated by one or both of the PCS and the electrical loads to at least one of the battery cells, raising its temperature by at least 5°C.

[0150] Unless explicitly required otherwise in the context, words such as “comprise,” “include,” and “comprising,” as understood throughout the description and claims, are interpreted in a comprehensive sense, as opposed to an exclusive or complete sense, i.e., “including, but not limited to.” Here, the commonly used word “combined” refers to two or more elements that may be directly linked or linked through one or more intermediate elements. Also, “here,” “above,” “below,” and words of similar meaning, when used in this application, refer to the application as a whole, rather than to a specific part of it. Where the context allows, the words in the above detailed descriptions that use singular or plural may each include plural or singular. Referring to two or more item lists, the word “or” includes any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0151] Furthermore, the conditional language used here, such as "can," "was able to," "had done," "may do," "example," "for example," and "like," is generally intended to convey that a particular embodiment includes certain features, elements, and / or states, but other embodiments do not, unless otherwise specified or understood within the context in which they are used. Therefore, these conditional words are not generally intended to imply that features, elements, and / or states are required in any way for one or more embodiments, or that these features, elements, and / or states are included in or performed in any particular embodiment.

[0152] While specific embodiments have been described, these embodiments are presented merely as examples and are not intended to limit the scope of this disclosure. In fact, the novel apparatus, methods, and systems described above can be embodied in a variety of other forms, and various omissions, substitutions, and modifications in the form of methods and systems described herein can be made without exceeding the scope of this disclosure. For example, while blocks are presented in a given arrangement, other embodiments may perform similar functions to other components and / or circuit topologies, and some blocks may be removed, moved, added, subdivided, combined, and / or modified. Each of these blocks can be embodied in a variety of ways that differ from one another. Any suitable combination of components and operations of the various embodiments described above can be combined to provide further embodiments. The various features and processes described above can be embodied independently of one another or combined in a variety of ways. Any possible combinations and subcombinations of the features of this disclosure are understood to be included within the scope of this disclosure.

Claims

1. Multiple battery cells electrically connected to each other, Multiple switches connected to each of the multiple battery cells, One or more heaters are electrically connected to the plurality of switches and dissipate power from the plurality of battery cells, One or more heat conduits are provided to send the heat generated by one or more heaters to at least one of the plurality of battery cells, including, Battery system.

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

3. The heat conduit includes an air conduit that delivers the heat by convection. The battery system according to claim 1.

4. The heat conduit includes a heat conduction pipe that transmits the heat by conduction. The battery system according to claim 1.

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

6. The heat generated by dissipating power in the plurality of battery cells is sent to the battery cell that dissipates the power and to the other battery cells. The battery system according to claim 1.

7. The system further includes a control unit electrically connected to the plurality of battery cells and the plurality of switches, The control unit uses one or more heaters to actively or passively balance the charge state (SoC) of the battery cell. The battery system according to claim 1.

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

9. The system further includes a plurality of temperature sensors that measure the temperature of at least one of the plurality of battery cells, The battery system according to claim 8.

10. When the control unit determines that the temperature of at least one of the plurality of battery cells is lower than a previously set temperature, it activates one or more of the switches. The battery system according to claim 8.

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

12. Each of the aforementioned plurality of battery cells is an oxidation-reduction battery cell, The aforementioned oxidation-reduction battery cell is A first half-cell containing a first electrolyte in which the first redox pair, which undergoes the first redox half-reaction, is dissolved inside, A second half-cell containing a second electrolyte in which a second redox pair, in which a second redox half-reaction occurs, is dissolved, An ion exchange membrane separating the first half cell and the second half cell, including, The battery system according to claim 1.

13. The process involves sensing the charge state (State of Charge) of multiple battery cells that are electrically connected to each other, The steps include: activating one or more switches connected to the plurality of battery cells to dissipate power and generate heat from one or more of the battery cells that have a charge state above a critical value already set by one or more heaters; A step of sending heat generated from one or more heaters via one or more heat conduits to at least one of the plurality of battery cells, including, Thermal management methods for battery systems.

14. The process further includes the step of charging and discharging the plurality of battery cells before sensing the aforementioned charge state, The thermal management method for a battery system according to claim 13.

15. The step of sensing the charging state includes the step of measuring the cell voltage, The aforementioned critical value of the charging state that has already been set is the average cell voltage. The thermal management method for a battery system according to claim 13.

16. The step further includes activating the cell balancing system based on the sensed charging state, The thermal management method for a battery system according to claim 13.

17. The process further includes sensing the temperature of at least one of the plurality of battery cells before transferring the heat, The thermal management method for a battery system according to claim 13.

18. The step of sending heat includes a step of sending heat when it is detected that the temperature of at least one of the plurality of battery cells is below a previously set temperature. The thermal management method for a battery system according to claim 17.

19. If the temperature of at least one of the plurality of battery cells is detected to be above the previously set temperature, the further step includes cooling at least one of the plurality of battery cells to a temperature below the previously set temperature. The thermal management method for a battery system according to claim 17.

20. The step of supplying heat includes supplying heat until the temperature of at least one of the battery cells reaches at least the previously set temperature. The thermal management method for a battery system according to claim 17.

21. Battery system and, A power control system (PCS) electrically connected to the aforementioned battery system, An electrical load electrically connected to the power control system, Includes, The aforementioned battery system Multiple battery cells electrically connected to each other, Multiple switches connected to each of the multiple battery cells, One or more heaters electrically connected to the plurality of switches to balance the charge state (SoC) of the plurality of battery cells actively or passively, Includes, The power control system and the electrical load, or one or both, are electrically connected to the grid. One or more of the battery system, the power control system, and the electrical loads are insulated from each other by an insulating material. Energy storage system.

22. Battery system and, A power control system (PCS) electrically connected to the aforementioned battery system, An electrical load electrically connected to the power control system, Includes, The aforementioned battery system Multiple battery cells electrically connected to each other, Multiple switches connected to each of the multiple battery cells, One or more heaters electrically connected to the plurality of switches to balance the charge state (SoC) of the plurality of battery cells actively or passively, Includes, The power control system and the electrical load, or both, are thermally connected to the battery system by one or more heat conduits that send the heat generated by the power control system and the electrical load, or both, to at least one of the battery cells. Energy storage system.

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