Heating control system, method and vehicle for solid-state battery

Abstract

The present application relates to the technical field of vehicle power battery, and particularly relates to a heating control system and method of solid-state battery and a vehicle, the system comprising a battery pack, a heating controller, N heating film groups and a battery management system; the battery management system is used for determining a target heating mode under a current temperature based on a maximum allowed discharge current corresponding to the current temperature of a solid-state cell in the battery pack and working currents corresponding to N heating modes respectively; the number of heating film groups working simultaneously under different heating modes is different; under any heating mode, the N heating film groups work in turn in a heating cycle, and the working time of each heating film group in the heating cycle is the same. In this way, the load resistance of the battery pack is adjusted by adjusting the number of heating film groups working simultaneously, and then the working current of the battery pack is adjusted to adapt to the discharge capacity of the solid-state cell in the battery pack under different temperatures, so that the cold start efficiency of the solid-state battery can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle power battery, and particularly relates to a heating control system and method of solid-state battery and a vehicle. BACKGROUND

[0002] Compared with a liquid battery cell, a solid-state battery cell has weak low-temperature discharge capability, and therefore a vehicle using a solid-state battery as a power battery needs to heat the solid-state battery cell at cold start to quickly improve the discharge capability of the solid-state battery cell and realize cold start of the solid-state battery.

[0003] An existing solid-state battery heating strategy uses a single heating film for heating. Since the solid-state battery cell has weak low-temperature discharge capability and the heating film is a pure resistance circuit, if the resistance of the heating film is designed to be small, the discharge cut-off voltage of the solid-state battery cell will be quickly reached, resulting in failure to continue heating; if the resistance of the heating film is designed to be large, the heating power will be slow and the heating efficiency will be low. The contradiction between the resistance of the heating film and the low-temperature discharge capability of the solid-state battery cell results in low cold start efficiency of the solid-state battery. SUMMARY

[0004] Therefore, the present application provides at least a heating control system and method of solid-state battery and a vehicle, which adjusts the number of simultaneously working heating film groups to adjust the load resistance of a battery pack, and then adjusts the working current of the battery pack to adapt to the discharge capability of a solid-state cell in the battery pack at different temperatures, so as to improve the cold start efficiency of the solid-state battery.

[0005] The present application mainly includes the following aspects:

[0006] In a first aspect, the present application provides a heating control system of solid-state battery, which comprises a battery pack, a heating controller, N heating film groups and a battery management system; the number N of the heating film groups is the same as the number M of solid-state battery modules in the battery pack; the positive electrodes of the heating film groups are connected in parallel and connected to the positive electrode of the battery pack, and the negative electrodes of the heating film groups are respectively connected to the first end of the heating controller; the second end of the heating controller is connected to the negative electrode of the battery pack; the battery management system is connected to the third end of the heating controller; wherein,

[0007] The battery management system is used to determine the target heating mode at the current temperature based on the maximum allowable discharge current corresponding to the current temperature of the solid-state cells in the battery pack and the operating current corresponding to N heating modes respectively; wherein, the number of heating film groups working simultaneously is different in different heating modes; in any heating mode, N heating film groups work in turn in a heating cycle, and each heating film group works for the same amount of time in a heating cycle.

[0008] The heating controller is used to control the working state of N heating film groups according to the target heating mode;

[0009] Any of the heating film groups is used to heat the solid-state battery module corresponding to the heating film group during operation;

[0010] The battery pack is used to power each of the heating film assemblies.

[0011] Secondly, embodiments of this application also provide a heating control method for a solid-state battery, applied to a battery management system in the heating control system of a solid-state battery as described above, the method comprising:

[0012] Obtain the current temperature of the solid-state cells in the battery pack, and determine the maximum allowable discharge current corresponding to the current temperature;

[0013] Based on the maximum allowable discharge current corresponding to the current temperature and the operating current corresponding to each of the N heating modes, a target heating mode is determined at the current temperature. This allows the heating controller to control the operating state of the N heating film groups according to the target heating mode, so that any one of the heating film groups heats the solid-state battery module corresponding to it when it is in operation. The number of heating film groups operating simultaneously varies under different heating modes. Under any heating mode, the N heating film groups work in turn during one heating cycle, and each heating film group operates for the same amount of time during one heating cycle.

[0014] Thirdly, embodiments of this application also provide a vehicle including a heating control system for a solid-state battery as described above.

[0015] This application provides a heating control system, method, and vehicle for a solid-state battery. The heating control system includes a battery pack, a heating controller, N heating film groups, and a battery management system. The number N of heating film groups is the same as the number M of solid-state battery modules in the battery pack. The positive terminals of each heating film group are connected in parallel and electrically connected to the positive terminal of the battery pack. The negative terminals of each heating film group are electrically connected to the first terminal of the heating controller. The second terminal of the heating controller is electrically connected to the negative terminal of the battery pack. The battery management system is communicatively connected to the third terminal of the heating controller. The battery management system is used to determine the target heating mode at the current temperature based on the maximum allowable discharge current corresponding to the current temperature of the solid-state cells in the battery pack and the operating current corresponding to the N heating modes. The number of heating film groups working simultaneously varies under different heating modes. Under any heating mode, the N heating film groups work sequentially in a heating cycle, and each heating film group works for the same amount of time in a heating cycle. The heating controller is used to control the working state of the N heating film groups according to the target heating mode. Each heating film group is used to heat the solid-state battery module corresponding to the heating film group during operation. The battery pack is used to supply power to each heating film group. In this way, by adjusting the number of heating film groups working simultaneously, the load resistance of the battery pack can be adjusted, thereby adjusting the operating current of the battery pack to match the discharge capacity of the solid-state cells in the battery pack at different temperatures, which can improve the cold start efficiency of solid-state batteries.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This illustration shows one of the structural schematic diagrams of a heating control system for a solid-state battery provided in an embodiment of this application;

[0019] Figure 2 A schematic diagram of the control timing for each heating mode in the example description of this application is shown;

[0020] Figure 3 A schematic diagram of the heating film assembly in an embodiment of this application is shown;

[0021] Figure 4 This paper shows a diagram illustrating the arrangement of the heating film assembly and the corresponding battery module in an embodiment of this application.

[0022] Figure 5 This is a second schematic diagram of the structure of a heating control system for a solid-state battery provided in an embodiment of this application;

[0023] Figure 6 A schematic diagram of the lumped thermal equivalent circuit model is shown.

[0024] Figure 7 A schematic diagram of the structure of the distributed thermal equivalent circuit model in an embodiment of this application is shown;

[0025] Figure 8 A flowchart of a heating control method for a solid-state battery provided in an embodiment of this application is shown;

[0026] Figure 9 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0028] To facilitate understanding of this application, the technical solutions provided in this application will be described in detail below with reference to specific embodiments.

[0029] This application provides a heating control system, method, and vehicle for solid-state batteries. By adjusting the number of heating film groups operating simultaneously, the load resistance of the battery pack is adjusted, thereby adjusting the operating current of the battery pack to adapt to the discharge capacity of the solid-state cells in the battery pack at different temperatures, which can improve the cold start efficiency of the solid-state battery.

[0030] Please see Figure 1 , Figure 1 This is one of the structural schematic diagrams of a heating control system for a solid-state battery provided in an embodiment of this application. Figure 1 As shown, the solid-state battery heating control system 100 provided in this application embodiment includes: a battery pack 110, a heating controller 120, N heating film groups 130, and a battery management system 140.

[0031] Specifically, the number N of heating film groups 130 is the same as the number M of solid-state battery modules in the battery pack 110; the positive terminals of each heating film group 130 are connected in parallel and electrically connected to the positive terminal of the battery pack 110, and the negative terminals of each heating film group 130 are electrically connected to the first terminal of the heating controller 120; the second terminal of the heating controller 120 is electrically connected to the negative terminal of the battery pack 110; and the battery management system 140 is communicatively connected to the third terminal of the heating controller 120.

[0032] The battery management system 140 is used to determine the target heating mode at the current temperature based on the maximum allowable discharge current corresponding to the current temperature of the solid-state cells in the battery pack 110 and the operating current corresponding to the N heating modes. The number of heating film groups 130 working simultaneously is different under different heating modes. Under any heating mode, the N heating film groups 130 work in turn in a heating cycle, and the working time of each heating film group 130 is the same in a heating cycle.

[0033] Here, to resolve the contradiction between the heating film resistance and the low-temperature discharge capability of solid-state battery cells in existing heating methods, this embodiment of the application sets up N heating film groups 130 in the heating control system 100. The number N of heating film groups 130 is the same as the number M of solid-state battery modules in the battery pack 110. Each heating film group 130 is responsible for heating the corresponding solid-state battery module. Depending on the number of heating film groups 130 operating simultaneously, N different heating modes can be provided, each with a different total heating film resistance. Specifically, if the module resistance of the heating film group is... N heating modes can be provided according to the different numbers of heating film groups 130 operating simultaneously. , , , There are a total of N gradients in the total resistance of the heating film. Thus, the heating mode is selected based on the maximum allowable discharge current corresponding to the current temperature of the solid-state cell in the battery pack 110 and the operating current corresponding to each of the N heating modes. When the solid-state cell temperature is low, its discharge capacity is weak, and it can only withstand a small operating current. In this case, a heating mode with fewer simultaneously operating heating film groups 130 can be used to provide a higher total heating film resistance, preventing the solid-state cell voltage from quickly reaching the discharge cutoff voltage and thus preventing further heating. As heating progresses, the temperature of the solid-state cell gradually increases, and its discharge capacity also continuously increases, allowing it to withstand a larger operating current. During the heating process of the solid-state battery, the operating mode can be gradually switched to increase the number of simultaneously operating heating film groups 130, thereby gradually reducing the total heating film resistance and gradually increasing the heating power to improve heating efficiency. This completely solves the contradiction between the heating film resistance and the low-temperature discharge capacity of the solid-state battery cell, effectively improving the cold-start efficiency of the solid-state battery.

[0034] Meanwhile, in order to ensure uniform heating of the battery pack, in any heating mode of the embodiments of this application, N heating film groups 130 work in turn in a heating cycle, and all N heating film groups 130 complete a complete heating cycle, and each heating film group 130 works for the same amount of time in a heating cycle.

[0035] In this embodiment, the number of heating film groups 130 is N=6. Note that N=6 is only used as an example and is not a specific limitation on the solution; other numbers of heating film groups 130 can also achieve the solution of this application.

[0036] The six heating film groups 130 can be divided into six heating modes: Heating Mode I, where only one heating film group works simultaneously; Heating Mode II, where two heating film groups work simultaneously; Heating Mode III, where three heating film groups work simultaneously; Heating Mode IV, where four heating film groups work simultaneously; Heating Mode V, where five heating film groups work simultaneously; and Heating Mode VI, where six heating film groups work simultaneously. The following example illustrates the cyclic heating, taking Heating Mode II as an example. In Heating Mode II, where two heating film groups work simultaneously, a high-speed cycle can be performed in the following order: heating film groups 1 and 2 work simultaneously, then heating film groups 3 and 4 work simultaneously, then heating film groups 5 and 6 work simultaneously; or heating film groups 1 and 4 work simultaneously, then heating film groups 2 and 5 work simultaneously, then heating film groups 3 and 6 work simultaneously, and so on. The key is to ensure that all six heating film groups 130 complete a full heating cycle, and that each heating film group 130 operates for the same amount of time within a heating cycle. The purpose of designing different heating modes is to change the total resistance of the entire heating circuit by altering the number of heating film groups 130 connected in parallel, thereby controlling the current in the heating circuit.

[0037] The heating controller 120 is used to control the working status of N heating film groups 130 according to the target heating mode.

[0038] Any heating film group 130 is used to heat the solid-state battery module corresponding to the heating film group 130 during operation.

[0039] Battery pack 110 is used to power each heating film assembly 130.

[0040] Furthermore, the battery management system 140 is specifically configured to determine the target heating mode at the current temperature based on the following steps:

[0041] Step a1: Query the maximum allowable discharge current corresponding to the current temperature from the preset temperature-current mapping table.

[0042] Here, based on the temperature characteristics of solid-state batteries, the maximum allowable discharge current of a solid-state battery at a certain temperature is determined. The current will increase continuously as the temperature rises. In this embodiment, the maximum allowable discharge current corresponding to the current temperature can be obtained by querying a preset temperature-current mapping table.

[0043] For example, suppose the initial heating temperature of a solid-state battery cell is -30°C. By consulting the preset temperature-current mapping table, we can see that the maximum allowable discharge current of the solid-state battery cell at this temperature is 30A. As the temperature increases, the maximum allowable discharge current is 60A at -20°C, 90A at -16°C, 60A at -13°C, 150A at -10°C, and 180A at -8°C.

[0044] Step a2: Calculate the operating current for each heating mode based on the open-circuit voltage of the battery pack, the total internal resistance of the battery pack, and the total resistance of the heating film corresponding to each heating mode.

[0045] In this embodiment of the application, the open-circuit voltage of the battery pack is The total internal resistance of the battery pack is The total resistance of the heating film depends on the number of heating film groups operating simultaneously and the resistance of each heating film group. Confirmed. When using heating mode VI, the operating current... When heating mode V is used, the operating current is... When heating mode IV is used, the operating current is... When heating mode III is used, the operating current is... When heating mode II is used, the operating current is... When heating mode I is used, the operating current is... Among them, the total internal resistance of the battery pack Based on the number of solid-state battery modules connected in parallel in battery pack 110 The number of solid-state cells connected in series in each solid-state battery module and the internal resistance of solid-state cells "Confirmed" can be expressed as: The operating current for each heating mode is then calculated.

[0046] Step a3: Among the heating modes where the operating current is less than the maximum allowable discharge current, select the heating mode with the highest operating current and determine it as the target heating mode.

[0047] Here, because the number of heating film groups 130 connected to the circuit simultaneously for different heating modes is different, the total resistance of the heating film corresponding to different heating modes is different, which in turn results in different operating currents for different heating modes. Based on the maximum allowable discharge current corresponding to the current temperature of the solid-state cell in the battery pack 110, and the operating current corresponding to each heating mode, the heating mode with the highest operating current among those whose operating current is less than the maximum allowable discharge current is selected as the target heating mode, thus adapting the determined target heating mode to the current temperature scenario of the solid-state cell. Specifically, the maximum allowable discharge current... Heating current for each heating mode , , , , , If a comparison is made, If so, select heating mode IV; if If so, select heating mode V; If so, select heating mode IV; if If so, select heating mode III; if If so, select heating mode II; if Then select heating mode I; if If the temperature is such that heating is not permitted at this temperature, then in this embodiment of the application, after a heating cycle, if... If the conditions for switching heating modes are met, the heating mode will be switched immediately to ensure the cold start efficiency of the solid-state battery.

[0048] The following example illustrates this point, showing the membrane resistor of the heating module. The resistance is designed to be 15Ω to ensure that the current does not exceed [a certain value]. 30A. Please refer to [reference needed]. Figure 2 , Figure 2 This is a schematic diagram illustrating the control timing of each heating mode in the examples described in this application. For example... Figure 2 As shown, at -30°C, At this time, heating mode I is selected, meaning that only one heating film group 130 is working at any given time, and the heating power is 13.5kW (through...). (Calculation); when the battery pack is heated to -20°C, The heating mode can be switched to Heating Mode II, in which case two heating film groups work simultaneously, and the total resistance of the heating films is... The heating power is increased to 27kW; when the temperature rises to -16°C, the maximum allowable discharge current is... Reaching 90A, The heating mode can be switched to heating mode III, which means that the number of heating film groups working simultaneously is 3, and the total resistance of the heating film is... The heating power reaches 40.5kW; when the temperature rises to -13°C, the maximum allowable discharge current... Reaching 120A, The heating mode can be switched to heating mode IV, meaning that the number of heating films working simultaneously is 4, and the total resistance of the heating films is... The heating power reaches 54kW; when the temperature rises to -10°C, the maximum allowable discharge current is... Reaching 150A, The heating mode can be switched to heating mode V, meaning that the number of heating films working simultaneously is 5, and the total resistance of the heating films is... 3Ω, heating power reaches 67.5kW; when the temperature rises to -8°C, the maximum allowable discharge current is... Reaching 180A, The heating mode can be switched to heating mode VI, which means that the number of heating films working simultaneously is 6, and the total resistance of the heating films is... With a resistance of 2.5Ω, the heating power reaches 81kW. Under this heating mode switching, the average heating power from -30°C to 0°C can reach 47.25kW, taking about 5 minutes, effectively improving the cold start efficiency of solid-state batteries.

[0049] Further, please refer to Figure 3 , Figure 3 This is a schematic diagram of the heating film assembly in an embodiment of this application. Figure 3 As shown, each heating film assembly 130 includes multiple heating films 131, multiple positive electrode connecting films 132, multiple negative electrode connecting films 133, a heating film positive electrode 134, and a heating film negative electrode 135; the multiple heating films 131 are connected in series, and two adjacent heating films 131 are connected through a positive electrode connecting film 132 and a negative electrode connecting film 133, respectively; the heating film positive electrode 134 is connected to the positive electrode of the heating film assembly 130 and the target heating film among the multiple heating films 131, respectively; the heating film negative electrode 135 is connected to the negative electrode of the heating film assembly 130 and the target heating film among the multiple heating films 131, respectively; the target heating film is the heating film among the multiple heating films 131 that is adjacent to the heating film positive electrode 134 and the heating film negative electrode 135.

[0050] In this embodiment, the heating film assembly 130 is composed of several heating films 131 connected in series, used to heat the corresponding battery module. The heating films 131 generate heat through their resistance; the positive electrode connecting film 132 and the negative electrode connecting film 133 connect the heating films 131 in series, serving as a connection and current-carrying mechanism; the positive electrode 134 and the negative electrode 135 of the heating films are used to connect the heating film assembly to an external circuit.

[0051] Furthermore, the film resistance of the heating film assembly 130 Equal to the heating film resistance of multiple heating films 131 The positive electrode connection film resistor of multiple positive electrode connection films 132 Negative electrode connection film resistor with multiple negative electrode connection films 133 The sum; the film resistance of the heating film module 130. Based on the target value and the total internal resistance of battery pack 110 The difference is determined, and the target value is the open-circuit voltage of battery pack 110. With the heating start temperature threshold of battery pack 110 The corresponding maximum allowable discharge current The ratio between them; the total internal resistance of the battery pack Based on the number of solid-state battery modules connected in parallel in battery pack 110 The number of solid-state cells connected in series in each solid-state battery module and the internal resistance of solid-state cells Sure.

[0052] In this embodiment of the application, the film resistance of the heating film assembly 130 It can be represented as: ;in, This refers to the number of heating films in heating film assembly 130. This is due to the resistance of the heating film assembly. The size directly affects the heating onset temperature threshold of solid-state batteries. Therefore, when conducting membrane resistance... When selecting, the heating start temperature threshold should be fully considered. The requirement. In the embodiments of this application, the membrane resistor The selection is calculated based on the following formula:

[0053] .

[0054] For example, suppose the minimum allowable heating temperature of battery pack 110 is, i.e., the heating start temperature threshold. For -30°C, by consulting the preset temperature-current mapping table, the maximum allowable discharge current at this temperature can be obtained. Then the membrane resistance The choice should ensure .

[0055] Further, please refer to Figure 4 , Figure 4 This is a diagram illustrating the arrangement of the heating film assembly and the corresponding battery module in an embodiment of this application. Figure 4 As shown, any heating film 131 is located between the two cells with the largest area in each cell group of the solid-state battery module; the solid-state battery module includes multiple cell groups, and each cell group includes two cells; the number of heating films 131 is equal to the number of cell groups in the solid-state battery module; the heating film resistance... Much greater than the positive electrode connection film resistance Film resistor connected to the negative electrode .

[0056] To address the issues of small effective heating area, long heat conduction path, and low efficiency per cell resulting from traditional heating schemes that use heating films on the top or bottom surface, this embodiment places the heating film 131 between the two cells with the largest area in each cell group of the solid-state battery module. This effectively shortens the heat transfer path and increases the heating area. Placing one heating film 131 between every two cells ensures uniform heating. Since the primary function of the heating film 131 is to generate heat through resistance, the resistance of the heating film... The selection is relatively large, usually With a resistance greater than 0.1Ω, and based on a 30A current, the heating power can be greater than 90W. The primary function of the positive electrode connecting film 132 and the negative electrode connecting film 133 is current carrying; heating is not required in this area. Therefore, the resistance of the positive electrode connecting film is... Film resistor connected to the negative electrode A smaller resistor will be chosen, usually With a resistance of <1mΩ, calculated at a current of 30A, the heating power can be kept <0.1W, avoiding the problem of dry burning caused by heat generation in this area, which could lead to potential insulation failure of the heating film. Therefore, in this embodiment, the heating film resistance... Much greater than the positive electrode connection film resistance Film resistor connected to the negative electrode .

[0057] Furthermore, such as Figure 4 As shown, the heating film assembly 130 also includes two end plates 136 and multiple buffer pads 137; the two end plates 136 are located at both ends of the heating film assembly 130; any buffer pad 137 is located between two adjacent cell groups; the two end plates 136 clamp and fix the heating film assembly 130 and the solid-state battery module by a preset pre-tightening force.

[0058] To address the issue of high contact thermal resistance and low heat transfer efficiency caused by the lack of close contact between the heating film and the battery cell in traditional heating solutions where the heating film is arranged on the top or bottom surface, the heating film assembly 130 in this embodiment further includes two end plates 136 and multiple buffer pads 137. The two end plates 136 are located at both ends of the heating film assembly 130; any buffer pad 137 is located between two adjacent battery cell groups; the two end plates 136 clamp and fix the heating film assembly 130 and the solid-state battery module with a preset pre-tightening force. In this way, the end plates 136 and the buffer pads 137 press the heating film 131 and the two batteries in the corresponding battery cell group together, forming a large pre-tightening force to reduce the contact thermal resistance between the heating film 131 and the battery cell, thereby improving the heat transfer efficiency between the heating film 131 and the battery cell. In this embodiment, a preload of 1 MPa or higher is used to clamp the two end plates 136, where 1 MPa is the minimum pressure required for the solid-state cell to perform normal charging and discharging functions. Furthermore, the end plates 136 can be positioned by bonding them to the lower casing of the battery pack. The buffer pad 137 is compressed in the entire pack state, and the rebound force can be controlled by designing the compression amount of the buffer pad 137.

[0059] Further, please refer to Figure 5 , Figure 5 This is a second schematic diagram of a heating control system for a solid-state battery provided in an embodiment of this application. Figure 5 As shown, the heating controller 120 includes a plurality of MOSFETs 121; the first end of each MOSFET 121 is electrically connected to the second end of each heating film assembly 130, the second end of each MOSFET 121 is electrically connected to the negative terminal of the battery pack 110, and the third end of each MOSFET 121 is communicatively connected to the battery management system 140.

[0060] The heating controller 120 is used to control the operating status of the N heating film groups 130 according to the following steps:

[0061] Based on the number of heating film groups 130 operating simultaneously under the target heating mode, determine the MOSFET 121 that is turned on at each moment and the corresponding on-time of the turned-on MOSFET 121, so as to control the operating state of the corresponding heating film group 130.

[0062] Here, the heating controller 120 determines the number of MOSFETs 121 that need to be synchronously turned on based on the target heating mode obtained from the battery management system 140, and divides the heating cycle into N equal time slots. By adjusting the duty cycle through pulse width modulation (PWM), the controller precisely controls the conduction time of each MOSFET 121, so that the N heating film groups 130 work in turn to control the working state of the corresponding heating film group 130. In this way, the heating power and temperature uniform distribution of the heating film group 130 can be adjusted.

[0063] Furthermore, the battery management system 140 is also used for:

[0064] Step b1: Determine the heating power density of the heating film group 130 based on the operating current of the target heating mode, the film resistance of the heating film group 130, the number of heating films in the heating film group 130, the area of ​​the heating film, and the duty cycle of the MOS transistor 121 corresponding to the heating film group 130.

[0065] Here, the heating film is prone to carbonization or insulation failure at high temperatures, therefore, the heating power density of the heating film needs to be controlled. In this embodiment, the battery management system 140 calculates the heating power density of the heating film in real time. Heating power density It can be represented as:

[0066] ;in, The operating current for the target heating mode. To measure the film resistance of the heating film module 130, This refers to the number of heating films in heating film assembly 130. For the heating film area, This refers to the duty cycle of the MOS transistor 121 corresponding to the heating film assembly 130.

[0067] Step b2: Based on the heating power density and the maximum allowable heating power density of the heating film group 130, adjust the duty cycle of the MOSFET 121 corresponding to the heating film group 130 so that the heating power density is maintained at the maximum allowable heating power density; the maximum allowable heating power density is determined based on the ambient temperature of the battery pack 110, the maximum allowable temperature of the heating film 131, and the cumulative usage time of the heating film 131; the duty cycle is determined based on the conduction time and heating cycle.

[0068] Here, if the heating power density is too high, it may cause risks such as delamination of the heating film insulation layer in the event of dry burning. If the heating power density is too low, it will lead to a decrease in heating efficiency. Therefore, in this embodiment, by comparing the heating power density of the heating film with the maximum allowable heating power density of the heating film and adjusting the duty cycle of the MOS transistor 121 corresponding to the heating film group 130, the heating power density is kept at the maximum allowable heating power density, which can ensure both the safety of the heating film and the heating efficiency. The maximum allowable heating power density is determined based on the ambient temperature of the battery pack 110, the maximum allowable temperature of the heating film 131, and the cumulative usage time of the heating film 131.

[0069] Furthermore, when the battery management system 140 adjusts the duty cycle of the MOSFET 121 corresponding to the heating film assembly 130 based on the heating power density and the maximum allowable heating power density of the heating film assembly 130, the battery management system 140 specifically performs the following:

[0070] Step c1: If the heating power density is greater than the maximum allowable heating power density, then reduce the duty cycle of the MOS transistor 121 corresponding to the heating film group 130.

[0071] Here, if the heating power density exceeds the maximum allowable heating power density, the duty cycle of the MOSFET 121 corresponding to the heating film assembly 130 is reduced. For example, if... Then the duty cycle Multiply by 0.9 from the original value.

[0072] Step c2: If the heating power density is less than the maximum allowable heating power density, increase the duty cycle of the MOS transistor 121 corresponding to the heating film group 130.

[0073] Here, if the heating power density is less than the maximum allowable heating power density, the duty cycle of the MOSFET 121 corresponding to the heating film assembly 130 is increased. For example, if... Then the duty cycle Multiply by 1.1 from the original value.

[0074] Furthermore, such as Figure 4 As shown, the heating control system 100 of the solid-state battery also includes a fuse 150 and a relay 160. The fuse 150 and the relay 160 are installed in parallel on the connection line between the positive terminals of each heating film group 130 and the positive terminal of the battery pack 110, so as to protect the circuit and prevent the battery pack 110 from being damaged due to abnormal control.

[0075] Furthermore, the battery management system 140 is also used to determine the current temperature of the solid-state cells in the battery pack according to the following steps:

[0076] Step d1: Input the internal temperature of the solid cell in the battery pack 110 during the previous heating cycle into the heat generation calculation model to calculate the total heat generation of the battery pack 110 and each heating film group 130 during the previous heating cycle.

[0077] Step d2: Input the internal temperature of the solid-state cells in the battery pack 110 during the previous heating cycle into the overall heat dissipation model to calculate the overall heat dissipation of the battery pack 110 during the previous heating cycle.

[0078] Step d3: The total heat generated by the battery pack 110 and each heating film group 130 in the previous heating cycle, the overall heat dissipation of the battery pack 110 in the previous heating cycle, and the surface temperature of the solid cells in the battery pack 110 in the previous heating cycle are input into the cell temperature prediction model to calculate the internal temperature of the solid cells in the battery pack 110 in the current heating cycle.

[0079] Step d4: Determine the internal temperature of the solid-state cell in the battery pack 110 during the current heating cycle as the current temperature of the solid-state cell in the battery pack 110.

[0080] In this embodiment, the battery management system can only collect the surface temperature of the solid-state cells in the battery pack through sensors. Since there is a certain difference between the surface temperature and the internal temperature of the cells, the surface temperature alone cannot accurately reflect the actual temperature of the solid-state cells, resulting in low accuracy of solid-state battery heating control and affecting the safety of solid-state battery use. Therefore, this application sets up a heat generation calculation model, a whole-pack heat dissipation model, and a cell temperature prediction model in the battery management system 140. By using the surface temperature of the solid-state cells in the battery pack 110, the internal temperature of the solid-state cells in the battery pack 110 is predicted, thereby improving the accuracy of the current temperature of the solid-state cells in the battery pack 110 and thus improving the accuracy of solid-state battery heating control.

[0081] Furthermore, the heat generation calculation model includes an operating current calculation module, a heating film heat transfer efficiency calculation module, and a heat generation calculation module. When the battery management system 140 inputs the internal temperature of the solid-state cells in the battery pack 110 during the previous heating cycle into the heat generation calculation model to calculate the total heat generation of the battery pack 110 and each heating film assembly 130 during the previous heating cycle, the battery management system 140 specifically performs the following:

[0082] Step e1: Based on the internal temperature of the solid-state cells in the battery pack 110 during the previous heating cycle and the state of charge of the battery pack 110 during the previous heating cycle, determine the open-circuit voltage of the battery pack 110 during the previous heating cycle.

[0083] Here, based on the internal temperature of the solid-state cells in the battery pack 110 State of charge of battery pack 110 The open-circuit voltage of battery pack 110 can be determined. Specifically, open-circuit voltage The internal temperature of a solid-state battery cell can be obtained by looking up a table or by training a neural network model. and state of charge As input, with open-circuit voltage The output open-circuit voltage is calculated using a model, and no specific restrictions are imposed here.

[0084] Step e2: Based on the internal temperature of the solid-state cell in the battery pack 110 during the previous heating cycle, the state of charge, duty cycle, and frequency of the battery pack 110 during the previous heating cycle, determine the internal resistance of the solid-state cell in the battery pack 110 during the previous heating cycle.

[0085] Here, based on the internal temperature of the solid-state cells in the battery pack 110 State of charge of battery pack 110 The duty cycle and frequency can be used to determine the internal resistance of the battery cells in battery pack 110. Specifically, the internal resistance of the battery cell The internal temperature of a solid-state battery cell can be measured by training a neural network model. State of charge of battery pack 110 The duty cycle and frequency are used as inputs, and the cell internal resistance is used as the input. The output is obtained from the cell internal resistance prediction model.

[0086] Step e3: Based on the heating film temperature and cumulative usage time of the heating film in the previous heating cycle, determine the film resistance of the heating film group 130 in the previous heating cycle.

[0087] Here, the film resistance of the heating film assembly 130 can be determined based on the heating film temperature and the cumulative usage time of the heating film. Specifically, the membrane resistance The neural network model can be trained using the heating film temperature and cumulative usage time of the heating film 130 as inputs, and the film resistance as input. The output heating film resistance prediction model was calculated.

[0088] Step e4: Input the open-circuit voltage of the battery pack 110 in the previous heating cycle, the internal resistance of the solid cell in the previous heating cycle, and the resistance of the heating film assembly 130 in the previous heating cycle into the working current calculation module to calculate the working current of the battery pack 110 in the previous heating cycle.

[0089] Here, the open-circuit voltage of battery pack 110 is... Internal resistance of solid-state battery cells and the film resistance of heating film module 130 Input operating current calculation module, through formula The operating current of battery pack 110 was calculated. .

[0090] Step e5: Input the state of charge of the battery pack 110 in the previous heating cycle, the cell thickness and cell expansion rate of the solid cell, and the stress-strain curve of the buffer pad 137 into the heat transfer efficiency calculation model of the heating film to calculate the heat transfer coefficient between the heating film group 130 and the corresponding solid battery module in the previous heating cycle.

[0091] Here, heat exchange between the battery and the electrothermal film is achieved through heat conduction, depending on the state of charge of the battery pack 110. By analyzing the cell thickness and expansion rate of the solid-state battery cell, as well as the stress-strain curve of the buffer pad 137, the heat transfer coefficient between the heating film assembly 130 and the corresponding solid-state battery module can be determined. Specifically, the heat transfer coefficient The state of charge of battery pack 110 can be trained using a neural network model. The solid-state battery cell's thickness and expansion rate, as well as the stress-strain curve of the buffer pad 137, are used as inputs, with the heat transfer coefficient as the parameter. The output heating film heat transfer efficiency was calculated using a model.

[0092] Step e6: Input the operating current and heat transfer coefficient of the previous heating cycle into the heat generation calculation module to calculate the total heat generation of the battery pack 110 and each heating film group 130 in the previous heating cycle.

[0093] Here, the operating current will be... and heat transfer coefficient Input into the heat generation calculation module, using the formula:

[0094] The total heat generated by the battery pack 110 and each heating film assembly 130 was calculated. .in, For the total heat generated by battery pack 110, The total heat generated by each heating film assembly 130 in the heating cycle corresponding to the heating mode. The heat generated by the battery when it performs work on the outside world. The entropy-heat coefficient term reflects the heat of reaction caused by temperature changes. In the embodiments of this application, the entropy-heat coefficient term is smaller than the Joule heat term under pulsed discharge conditions. This is mainly because the entropy-heat coefficient is on a smaller order of magnitude, and the current is already very large under pulsed discharge conditions. In the other two terms, the current is a square term, so the entropy-heat coefficient term is ignored in the calculation. Total resistance of the heating film The generated Joule heat, of which, The effective heat transfer coefficient between the heating film 131 and the battery cell is used to correct the proportion of heat actually transferred to the battery cell.

[0095] Furthermore, when the battery management system 140 inputs the internal temperature of the solid-state cells in the battery pack 110 during the previous heating cycle into the overall heat dissipation model to calculate the overall heat dissipation of the battery pack 110 during the previous heating cycle, the battery management system 140 specifically performs the following:

[0096] Step f1: Based on the internal temperature of the solid-state cells in the battery pack 110 during the previous heating cycle, the ambient temperature during the previous heating cycle, the convective heat transfer coefficient and heat dissipation area of ​​each solid-state battery module in the battery pack 110, calculate the heat dissipation power of each solid-state battery module in the battery pack 110 during the previous heating cycle.

[0097] Here, based on the internal temperature of the solid-state cells in the battery pack 110 Ambient temperature The convective heat transfer coefficient of each solid-state battery module in the battery pack 110 and heat dissipation area Through formula The heat dissipation power of each solid-state battery module in the battery pack 110 was calculated. , , , .

[0098] Step f2: Based on the heat dissipation power of each solid-state battery module in the battery pack 110 in the previous heating cycle, calculate the total heat dissipation of the battery pack 110 in the previous heating cycle.

[0099] Here, the heat dissipation power of each solid-state battery module in the battery pack 110 is... , , , Summing is performed to calculate the overall heat dissipation of battery pack 110. .

[0100] Furthermore, when the battery management system 140 inputs the total heat generation of the battery pack 110 and each heating film assembly 130 in the previous heating cycle, the overall heat dissipation of the battery pack 110 in the previous heating cycle, the heating power density of each heating film assembly 130 in the previous heating cycle, and the cell surface temperature of the solid-state cells in the battery pack 110 in the previous heating cycle into the cell temperature prediction model to calculate the internal temperature of the solid-state cells in the battery pack 110 in the current heating cycle, the battery management system 140 specifically performs the following:

[0101] Step g1: Based on the total heat generated by the battery pack 110 and each heating film group 130 in the previous heating cycle, the overall heat dissipation of the battery pack 110 in the previous heating cycle, and the heating power density of each heating film group 130 in the previous heating cycle, determine the cell heating power of the solid-state cells of the battery pack 110 in the previous heating cycle.

[0102] In this embodiment, the internal temperature of the solid-state battery cell is predicted by establishing a thermally equivalent circuit model. For details, please refer to... Figure 6 , Figure 6 This is a schematic diagram of the lumped thermal equivalent circuit model. (Example:) Figure 6 As shown, for small battery cells, assuming uniform heat generation and temperature distribution throughout the cell, the cell temperature can be described by the temperature of a single point mass, which can be represented by a lumped thermal model. Similar to the equivalent circuit model in electrical circuits, the lumped thermal equivalent circuit model vividly represents the cell's heat generation, temperature rise (heat storage), and heat exchange, as well as the cell's heat capacity. Indicates the thermal storage of the battery cell, equivalent thermal resistance. This represents the resistance to heat exchange between the battery and its surrounding environment. Thermal parameters can be compared to electrical constants; for example, heat capacity and equivalent thermal resistance can be compared to capacitance and resistance, respectively, and temperature and heating power can be compared to electric potential and current source, respectively.

[0103] However, for larger solid-state cells, especially under conditions of high heat generation, the internal temperature distribution is usually uneven. To address this, this embodiment models the temperature distribution along the battery thickness direction, assuming a uniform temperature distribution on a plane perpendicular to the cell thickness direction. This assumption is reasonable when a heating film is installed on the plane perpendicular to the battery thickness direction. The battery can then be divided into multiple equal parts along its thickness direction. Based on the principle of the lumped thermal equivalent circuit model described above, a distributed thermal equivalent circuit model along the cell thickness direction is established. Generally, the more equal parts the battery is divided along its thickness direction, the more accurate the description of the internal temperature of the cell, but the model becomes very complex and computationally intensive. Considering all factors, this embodiment divides the solid-state cells of the battery pack 110 into two equal parts along the direction perpendicular to the surface with the largest area of ​​the cell. An initial distributed thermal equivalent circuit model is constructed based on the positional relationship between the solid-state cells of the battery pack 110 and the heating film of the heating film assembly 130.

[0104] Specifically, please refer to Figure 7 , Figure 7 This is a schematic diagram of the distributed thermal equivalent circuit model in an embodiment of this application. Figure 7 As shown, it is assumed that the temperature distribution of each equal segment of the solid-state battery cell is uniform, and each segment is equivalent to a lumped thermal equivalent circuit model, which includes heat capacity, heat generation, and thermal resistance for heat exchange with surrounding objects; assuming the thermal resistance of heat exchange between the battery segments... Same, thermal resistance and thermal resistance Thermal resistance represents the resistance to heat exchange between a surface perpendicular to the battery thickness direction and its surrounding environment. and thermal resistance This represents the heat exchange resistance between the surface perpendicular to the battery thickness direction and the heating film. The ambient temperature; , , , The surface temperature of the battery cell. , This refers to the internal temperature of the battery cell. The surface temperature of the heating film. , This refers to the heating power of the battery cell.

[0105] According to Kirchhoff's Current Law, at any given moment, for any node in a circuit (the connection point of three or more circuit elements), the sum of all currents flowing into that node is equal to the sum of all currents flowing out of that node.

[0106] Regarding the cell surface temperature It satisfies the following constraints:

[0107] ; , , Similarly.

[0108] Regarding the internal temperature of the battery cell It satisfies the following constraints:

[0109] ; Similarly.

[0110] Based on Kirchhoff's circuit laws, a thermal equivalent circuit model was constructed in MATLAB. When identifying the model parameters, the measured cell surface temperature, ambient temperature, heating power of the electrothermal film, and heating power of the cell were used as inputs, and the simulated cell surface temperature and internal cell temperature were used as outputs. The model parameters were identified using the Adaptive Particle Swarm Optimization (APSO) algorithm, with the objective function being the measured cell surface temperature. , , , The cell surface temperature obtained from simulation , , , The sum of squared deviations is specifically expressed as:

[0111] ;

[0112] By minimizing this objective function, the simulated temperature of the model, especially the simulated internal temperature of the battery cell, can be optimized. , By approximating the actual internal temperature of the battery cell as closely as possible, the parameters of the thermal equivalent circuit model can be optimized and identified, resulting in a well-constructed distributed thermal equivalent circuit model.

[0113] To achieve this process, it is first necessary to determine the total heat generated by the battery pack 110 and each heating film assembly 130. Heat dissipation of the entire battery pack 110 and the heating power density of each heating film assembly 130 The cell heating power of the solid-state battery cells in battery pack 110 was calculated. .

[0114] Step g2: Input the cell heating power of the solid-state cell in the battery pack 110 in the previous heating cycle, the heating power density of each heating film group 130 in the previous heating cycle, and the cell surface temperature of the solid-state cell in the battery pack 110 in the previous heating cycle into the constructed distributed thermal equivalent circuit model to calculate the cell internal temperature of the solid-state cell in the battery pack 110 in the current heating cycle.

[0115] Here, the cell heating power of the solid-state cell in the battery pack 110 in the previous heating cycle, the heating power density of each heating film group 130 in the previous heating cycle, and the cell surface temperature of the solid-state cell in the battery pack 110 in the previous heating cycle are input into the constructed distributed thermal equivalent circuit model. According to the constraints in step g1, the cell internal temperature of the solid-state cell in the battery pack 110 in the current heating cycle is calculated to obtain the current temperature of the solid-state cell.

[0116] Specifically, a distributed thermal equivalent circuit model is constructed according to the following steps:

[0117] The solid-state cells of the battery pack are divided into two equal parts in the direction perpendicular to the surface with the largest area, and an initial distributed thermal equivalent circuit model is constructed based on the positional relationship between the solid-state cells of the battery pack and the heating film of the heating film group.

[0118] Using minimizing the sum of squares of the cell surface temperature prediction error as the objective function, the model parameters of the initial distributed thermal equivalent circuit model are adjusted to obtain the constructed distributed thermal equivalent circuit model.

[0119] This application provides a heating control system for a solid-state battery, including a battery pack, a heating controller, N heating film groups, and a battery management system. The number N of heating film groups is the same as the number M of solid-state battery modules in the battery pack. The positive terminals of each heating film group are connected in parallel and electrically connected to the positive terminal of the battery pack. The negative terminals of each heating film group are electrically connected to the first terminal of the heating controller. The second terminal of the heating controller is electrically connected to the negative terminal of the battery pack. The battery management system is communicatively connected to the third terminal of the heating controller. The battery management system is used to determine the target heating mode at the current temperature based on the maximum allowable discharge current corresponding to the current temperature of the solid-state cells in the battery pack and the operating current corresponding to the N heating modes. The number of heating film groups working simultaneously varies under different heating modes. Under any heating mode, the N heating film groups work sequentially in a heating cycle, and each heating film group works for the same amount of time in a heating cycle. The heating controller is used to control the working state of the N heating film groups according to the target heating mode. Each heating film group is used to heat the solid-state battery module corresponding to the heating film group during operation. The battery pack is used to supply power to each heating film group. In this way, by adjusting the number of heating film groups working simultaneously, the load resistance of the battery pack can be adjusted, thereby adjusting the operating current of the battery pack to match the discharge capacity of the solid-state cells in the battery pack at different temperatures, which can improve the cold start efficiency of solid-state batteries.

[0120] Based on the same application concept, this application also provides a solid-state battery heating control method corresponding to the solid-state battery heating control system provided in the above embodiments. Since the principle of solving the problem by the method in this application is similar to that of the solid-state battery heating control system in the above embodiments of this application, the implementation of the method can refer to the implementation of the system, and the repeated parts will not be described again.

[0121] The solid-state battery heating control method provided in this application embodiment is applied to the battery management system 140 in the solid-state battery heating control system 100 provided in the above embodiment. Please refer to... Figure 8 , Figure 8 This is a flowchart illustrating a heating control method for a solid-state battery provided in an embodiment of this application. Figure 8 As shown, the heating control method for solid-state batteries includes:

[0122] S801, obtain the current temperature of the solid-state cells in the battery pack, and determine the maximum allowable discharge current corresponding to the current temperature.

[0123] S802, based on the maximum allowable discharge current corresponding to the current temperature and the operating current corresponding to each of the N heating modes, a target heating mode at the current temperature is determined, so that the heating controller controls the working state of the N heating film groups according to the target heating mode, so that any one of the heating film groups heats the solid-state battery module corresponding to the heating film group when it is working; wherein, the number of heating film groups working simultaneously is different in different heating modes; in any heating mode, the N heating film groups work in turn in a heating cycle, and the working time of each heating film group is the same in a heating cycle.

[0124] This application provides a heating control method for solid-state batteries, applied to a battery management system within a heating control system for solid-state batteries. The method includes: acquiring the current temperature of the solid-state cells in the battery pack and determining the maximum allowable discharge current corresponding to the current temperature; determining a target heating mode at the current temperature based on the maximum allowable discharge current corresponding to the current temperature and the operating currents corresponding to N heating modes, so that the heating controller controls the operating state of N heating film groups according to the target heating mode, so that any heating film group heats the solid-state battery module corresponding to its operating state during operation; wherein the number of heating film groups operating simultaneously differs under different heating modes; under any heating mode, the N heating film groups operate sequentially in a heating cycle, with each heating film group operating for the same duration within a heating cycle. By adjusting the number of simultaneously operating heating film groups to adjust the load resistance of the battery pack, and thus the operating current of the battery pack, the method adapts to the discharge capacity of the solid-state cells in the battery pack at different temperatures, thereby improving the cold-start efficiency of the solid-state battery.

[0125] Based on the same concept, this embodiment also provides a vehicle including the heating control system for the solid-state battery provided in the above embodiment.

[0126] Based on the same application concept, please refer to Figure 9 , Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 9 As shown, the electronic device 900 includes a processor 910, a memory 920, and a bus 930.

[0127] The memory 920 stores machine-readable instructions executable by the processor 910. When the electronic device 900 is running, the processor 910 and the memory 920 communicate through the bus 930. When the machine-readable instructions are executed by the processor 910, they perform the steps of the solid-state battery heating control method provided in the above embodiment. For specific implementation details, please refer to the method embodiment, which will not be repeated here.

[0128] Based on the same concept, this application also provides a computer-readable storage medium storing a computer program. When the computer program is run by a processor, it executes the steps of the heating control method for solid-state batteries provided in the above embodiments. For specific implementation details, please refer to the method embodiments, which will not be repeated here.

[0129] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and unit can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0130] In the embodiments provided in this application, it should be understood that the disclosed systems, methods, and vehicles can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0131] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0132] In addition, the functional units in the embodiments provided in this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0133] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0134] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0135] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A heating control system for a solid-state battery, characterized in that, The heating control system of the solid-state battery includes a battery pack, a heating controller, N heating film groups, and a battery management system; the number N of the heating film groups is the same as the number M of the solid-state battery modules in the battery pack; the positive terminals of each heating film group are connected in parallel and electrically connected to the positive terminal of the battery pack, and the negative terminals of each heating film group are electrically connected to the first terminal of the heating controller; the second terminal of the heating controller is electrically connected to the negative terminal of the battery pack; the battery management system is communicatively connected to the third terminal of the heating controller; wherein, The battery management system is used to determine the target heating mode at the current temperature based on the maximum allowable discharge current corresponding to the current temperature of the solid-state cells in the battery pack and the operating current corresponding to N heating modes. The number of heating film groups operating simultaneously varies under different heating modes. In any heating mode, the N heating film groups operate sequentially in a heating cycle, with each heating film group operating for the same amount of time within a heating cycle. During the heating process of the solid-state battery, the heating mode is gradually switched to increase the number of heating film groups operating simultaneously. The heating controller is used to control the working state of N heating film groups according to the target heating mode; Any of the heating film groups is used to heat the solid-state battery module corresponding to the heating film group during operation; The battery pack is used to power each of the heating film assemblies.

2. The heating control system for a solid-state battery according to claim 1, characterized in that, The battery management system is specifically used to determine the target heating mode at the current temperature according to the following steps: From the preset temperature-current mapping table, look up the maximum allowable discharge current corresponding to the current temperature; The operating current of each heating mode is calculated based on the open-circuit voltage of the battery pack, the total internal resistance of the battery pack, and the total resistance of the heating film corresponding to each heating mode. Among the heating modes where the operating current is less than the maximum allowable discharge current, the heating mode with the highest operating current is selected as the target heating mode.

3. The heating control system for a solid-state battery according to claim 1, characterized in that, Each heating film assembly includes multiple heating films, multiple positive electrode connecting films, multiple negative electrode connecting films, a heating film positive electrode, and a heating film negative electrode; the multiple heating films are connected in series, and two adjacent heating films are connected by a positive electrode connecting film and a negative electrode connecting film, respectively; the heating film positive electrode is connected to the positive electrode of the heating film assembly and the target heating film among the multiple heating films; the heating film negative electrode is connected to the negative electrode of the heating film assembly and the target heating film among the multiple heating films; the target heating film is the heating film that is adjacent to the heating film positive electrode and the heating film negative electrode among the multiple heating films.

4. The heating control system for a solid-state battery according to claim 3, characterized in that, The resistance of the heating film assembly is equal to the sum of the heating film resistances of the plurality of heating films, the positive electrode connection film resistances of the plurality of positive electrode connection films, and the negative electrode connection film resistances of the plurality of negative electrode connection films. The resistance of the heating film assembly is determined based on the difference between a target value and the total internal resistance of the battery pack. The target value is the ratio between the open-circuit voltage of the battery pack and the maximum allowable discharge current corresponding to the heating start temperature threshold of the battery pack. The total internal resistance of the battery pack is determined based on the number of solid-state battery modules connected in parallel in the battery pack, the number of solid-state cells connected in series in each solid-state battery module, and the internal resistance of the solid-state cells.

5. The heating control system for a solid-state battery according to claim 4, characterized in that, Each of the heating films is located between the two largest surfaces of cells in each cell group of the solid-state battery module; the solid-state battery module includes multiple cell groups, and each cell group includes two cells; the number of heating films is equal to the number of cell groups in the solid-state battery module; the resistance of the heating film is much greater than the resistance of the positive electrode connection film and the resistance of the negative electrode connection film.

6. The heating control system for a solid-state battery according to claim 5, characterized in that, The heating film assembly also includes two end plates and multiple buffer pads; the two end plates are located at both ends of the heating film assembly; any one of the buffer pads is located between two adjacent cell groups; the two end plates clamp and fix the heating film assembly and the solid-state battery module by a preset pre-tightening force.

7. The heating control system for a solid-state battery according to claim 6, characterized in that, The heating controller includes multiple MOSFETs; the first terminal of each MOSFET is electrically connected to the second terminal of each heating film assembly, the second terminal of each MOSFET is electrically connected to the negative terminal of the battery pack, and the third terminal of each MOSFET is communicatively connected to the battery management system; the heating controller is used to control the operating state of N heating film assemblies according to the following steps: Based on the number of heating film groups operating simultaneously under the target heating mode, the MOS transistors that are turned on at each moment and the corresponding on-time of the turned-on MOS transistors are determined in order to control the operating state of the corresponding heating film groups.

8. The heating control system for a solid-state battery according to claim 7, characterized in that, The battery management system is also used for: The heating power density of the heating film group is determined based on the operating current of the target heating mode, the film resistance of the heating film group, the number of heating films in the heating film group, the area of ​​the heating film, and the duty cycle of the MOS transistor corresponding to the heating film group. Based on the heating power density and the maximum allowable heating power density of the heating film group, the duty cycle of the MOS transistor corresponding to the heating film group is adjusted so that the heating power density is maintained at the maximum allowable heating power density; the maximum allowable heating power density is determined based on the ambient temperature of the battery pack, the maximum allowable temperature of the heating film, and the cumulative usage time of the heating film; the duty cycle is determined based on the conduction time and heating cycle.

9. The heating control system for a solid-state battery according to claim 8, characterized in that, When the battery management system adjusts the duty cycle of the MOSFET corresponding to the heating film group based on the heating power density and the maximum allowable heating power density of the heating film group, the battery management system is specifically used for: If the heating power density is greater than the maximum allowable heating power density, then reduce the duty cycle of the MOS transistor corresponding to the heating film group; If the heating power density is less than the maximum allowable heating power density, then increase the duty cycle of the MOS transistor corresponding to the heating film group.

10. The heating control system for a solid-state battery according to claim 7, characterized in that, The battery management system is also used to determine the current temperature of the solid-state cells in the battery pack according to the following steps: The internal temperature of the solid-state cells in the battery pack during the previous heating cycle is input into the heat generation calculation model to calculate the total heat generation of the battery pack and each of the heating film groups during the previous heating cycle. The internal temperature of the solid-state cells in the battery pack during the previous heating cycle is input into the overall heat dissipation model of the battery pack to calculate the overall heat dissipation of the battery pack during the previous heating cycle. The total heat generated by the battery pack and each of the heating film groups in the previous heating cycle, the overall heat dissipation of the battery pack in the previous heating cycle, the heating power density of each of the heating film groups in the previous heating cycle, and the cell surface temperature of the solid-state cells in the battery pack in the previous heating cycle are input into the cell temperature prediction model to calculate the internal temperature of the solid-state cells in the battery pack in the current heating cycle. The internal temperature of the solid-state cell in the battery pack during the current heating cycle is determined as the current temperature of the solid-state cell in the battery pack.

11. The heating control system for a solid-state battery according to claim 10, characterized in that, The heat generation calculation model includes a working current calculation module, a heating film heat transfer efficiency calculation module, and a heat generation calculation module. When the battery management system inputs the internal temperature of the solid-state cells in the battery pack during the previous heating cycle into the heat generation calculation model to calculate the total heat generation of the battery pack and each of the heating film assemblies during the previous heating cycle, the battery management system is specifically used for: Based on the internal temperature of the solid-state cells in the battery pack during the previous heating cycle and the state of charge of the battery pack during the previous heating cycle, the open-circuit voltage of the battery pack during the previous heating cycle is determined. Based on the internal temperature of the solid-state cells in the battery pack during the previous heating cycle, the state of charge, duty cycle, and frequency of the battery pack during the previous heating cycle, the internal resistance of the solid-state cells in the battery pack during the previous heating cycle is determined. Based on the heating film temperature and cumulative usage time of the heating film in the previous heating cycle, the film resistance of the heating film group in the previous heating cycle is determined. The open-circuit voltage of the battery pack in the previous heating cycle, the internal resistance of the solid cell in the previous heating cycle, and the resistance of the heating film assembly in the previous heating cycle are input into the working current calculation module to calculate the working current of the battery pack in the previous heating cycle. The state of charge of the battery pack in the previous heating cycle, the cell thickness and cell expansion rate of the solid cell, and the stress-strain curve of the buffer pad are input into the heat transfer efficiency calculation model of the heating film to calculate the heat transfer coefficient between the heating film group and the corresponding solid battery module in the previous heating cycle. The operating current and heat transfer coefficient of the previous heating cycle are input into the heat generation calculation module to calculate the total heat generation of the battery pack and each of the heating film groups in the previous heating cycle.

12. The heating control system for a solid-state battery according to claim 10, characterized in that, When the battery management system inputs the internal temperature of the solid-state cells in the battery pack during the previous heating cycle into the overall heat dissipation model to calculate the overall heat dissipation of the battery pack during the previous heating cycle, the battery management system is specifically used for: Based on the internal temperature of the solid-state cells in the battery pack during the previous heating cycle, the ambient temperature during the previous heating cycle, the convective heat transfer coefficient and heat dissipation area of ​​each solid-state battery module in the battery pack, the heat dissipation power of each solid-state battery module in the battery pack during the previous heating cycle is calculated. The total heat dissipation of the battery pack in the previous heating cycle is calculated based on the heat dissipation power of each solid-state battery module in the battery pack in the previous heating cycle.

13. The heating control system for a solid-state battery according to claim 10, characterized in that, When the battery management system inputs the total heat generated by the battery pack and each of the heating film assemblies in the previous heating cycle, the overall heat dissipation of the battery pack in the previous heating cycle, the heating power density of each of the heating film assemblies in the previous heating cycle, and the surface temperature of the solid-state cells in the battery pack in the previous heating cycle into the cell temperature prediction model to calculate the internal temperature of the solid-state cells in the battery pack in the current heating cycle, the battery management system is specifically used for: The cell heating power of the solid-state cells of the battery pack in the previous heating cycle is determined based on the total heat generated by the battery pack and each of the heating film groups in the previous heating cycle, the overall heat dissipation of the battery pack in the previous heating cycle, and the heating power density of each of the heating film groups in the previous heating cycle. The solid-state cells of the battery pack in the previous heating cycle, the heating power density of each heating film group in the previous heating cycle, and the surface temperature of the solid-state cells in the battery pack in the previous heating cycle are input into the constructed distributed thermal equivalent circuit model to calculate the internal temperature of the solid-state cells in the battery pack in the current heating cycle.

14. A heating control method for a solid-state battery, characterized in that, A battery management system applied in a heating control system for a solid-state battery as described in any one of claims 1 to 13, the method comprising: Obtain the current temperature of the solid-state cells in the battery pack, and determine the maximum allowable discharge current corresponding to the current temperature; Based on the maximum allowable discharge current corresponding to the current temperature and the operating current corresponding to each of the N heating modes, a target heating mode is determined at the current temperature. This allows the heating controller to control the operating state of the N heating film groups according to the target heating mode, so that any one of the heating film groups heats the solid-state battery module it corresponds to. The number of heating film groups operating simultaneously varies depending on the heating mode. In any heating mode, the N heating film groups work sequentially in a heating cycle, with each heating film group operating for the same amount of time within that cycle. During the heating process of the solid-state battery, the heating mode is gradually switched to increase the number of heating film groups operating simultaneously.

15. A vehicle, characterized in that, Including a heating control system for a solid-state battery as described in any one of claims 1 to 13.

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