Battery heating method and device of active equalization energy storage parallel system

Abstract

The invention discloses a battery heating method and device of an active equalization energy storage parallel system, and belongs to the field of energy storage battery management. The method comprises the following steps: adjusting and controlling the voltage of an embedded capacitor according to the adjusting current of an auxiliary power supply electrically connected with the input end of the embedded capacitor of the active equalization energy storage parallel system, so as to enable the embedded capacitor to be in a voltage stabilization state; and when the embedded capacitor is in a voltage stabilizing state, heating current for heating each branch battery is generated according to excitation signals applied to the two sides of the half-bridge switch of each branch of the active equalization energy storage parallel system. According to the invention, the battery of the active equalization energy storage parallel system can be heated without adding new elements.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage battery management, and in particular to a battery heating method and device for an active balanced energy storage parallel system. Background Art

[0002] With the development of new energy systems and the continued rapid increase in the proportion of renewable energy installed capacity, the intermittent and unstable nature of fluctuating renewable energy sources has led to an increasing reliance on energy storage in power systems. This has made new energy storage a key technology in building new power systems. This has led to the development of active balancing energy storage, connecting parallel battery clusters to store energy, to meet the large-capacity requirements of energy storage systems.

[0003] In related technologies, batteries need to be heated to ensure they maintain good performance, safety, and a long service life in low-temperature environments. Traditional heating methods often require additional heating elements or complex heating circuits, which not only pose safety risks but also generate electromagnetic interference to surrounding electronic equipment.

[0004] Based on this, there is an urgent need for a battery heating method and device for an active balanced energy storage parallel system to solve the above technical problems. Summary of the Invention

[0005] The present invention provides a method and device for heating batteries in an active balancing energy storage parallel system, which can achieve heating of batteries in the active balancing energy storage parallel system without adding new components. The technical solution is as follows:

[0006] In one aspect, a method for heating batteries in an active balanced parallel energy storage system is provided, the method comprising:

[0007] Regulating and controlling the voltage of the embedded capacitor according to the regulated current of the auxiliary power supply electrically connected to the input terminal of the embedded capacitor of the active balanced energy storage parallel system, so that the embedded capacitor is in a voltage-stabilized state;

[0008] When the embedded capacitor is in a voltage-stabilizing state, a heating current for heating the battery in each branch is generated according to the excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system.

[0009] In another aspect, a battery heating device for an active balanced energy storage parallel system is provided, the device comprising:

[0010] A control module, configured to regulate and control the voltage of the embedded capacitor according to a regulated current of an auxiliary power supply electrically connected to an input terminal of the embedded capacitor of the active balanced energy storage parallel system, so as to keep the embedded capacitor in a voltage-stabilized state;

[0011] A generating module is used to generate a heating current for heating the battery of each branch according to the excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system when the embedded capacitor is in a voltage-stabilized state.

[0012] On the other hand, a computer device is provided, comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of the above-mentioned battery heating method and device for the active balancing energy storage parallel system.

[0013] The technical solution provided by the present invention can achieve at least the following beneficial effects: Utilizing an embedded converter, an excitation signal with variable frequency and amplitude is applied to its switching device, thereby inducing an AC heating current. This method not only eliminates the need for complex pulse generation and control circuitry, reducing system design complexity and cost, and improving battery life, but also avoids compatibility issues such as electromagnetic interference caused by the transient impact of the pulse current, which can affect the normal operation of surrounding electronic devices. Furthermore, this method is simple to control, easy to implement, and does not require the addition of new components, making it suitable for active balanced energy storage parallel systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 This is a flow chart of a battery heating method for an active balanced energy storage parallel system provided by one embodiment of the present invention;

[0016] Figure 2 This is a circuit diagram of an active balanced energy storage parallel system provided by an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of a heating mode circuit of an active balanced energy storage parallel system provided by an embodiment of the present invention;

[0018] Figure 4 This is a flow chart of embedded capacitor voltage regulation provided by one embodiment of the present invention;

[0019] Figure 5 1 is a voltage diagram of an embedded converter in an active balancing energy storage parallel system provided by an embodiment of the present invention;

[0020] Figure 6Schematic diagram of a heating current simulation curve and a solved heating current function curve provided by an embodiment of the present invention;

[0021] Figure 7 1 is a schematic diagram of an excitation signal waveform provided by an embodiment of the present invention;

[0022] Figure 8 This is a schematic diagram of the relationship between the heating current and the amplitude and frequency of the excitation signal provided by an embodiment of the present invention;

[0023] Figure 9 This is a structural diagram of a battery heating device in an active balanced energy storage parallel system provided by one embodiment of the present invention;

[0024] Figure 10 This is a hardware architecture diagram of a computer device provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] As mentioned above, in the field of battery heating technology, traditional heating methods have many limitations. External heating methods will cause a large amount of heat to be lost during conduction, resulting in low heating efficiency; long-term use of pulse heating will significantly shorten battery life, so neither is suitable for active balancing energy storage parallel systems.

[0027] Based on this, the idea of ​​the present invention is to use the system's built-in converter to apply a switching function with variable frequency and amplitude to its switching device, thereby inducing an AC heating current. This method is simple to control, easy to implement, and does not require the addition of new components. It is suitable for active balanced energy storage parallel systems.

[0028] The specific implementation of the above concept is described below.

[0029] Please refer to Figure 1 An embodiment of the present invention provides a battery heating method for an active balanced energy storage parallel system, the method comprising:

[0030] Step 100, regulating and controlling the voltage of the embedded capacitor according to the regulated current of the auxiliary power supply electrically connected to the input terminal of the embedded capacitor of the active balanced energy storage parallel system, so that the embedded capacitor is in a voltage-regulated state;

[0031] Step 102 : When the embedded capacitor is in a voltage-stabilized state, a heating current for heating the battery in each branch is generated according to an excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system.

[0032] In an embodiment of the present invention, an embedded converter is used to apply a variable-frequency and variable-amplitude excitation signal to its switching device, thereby inducing an AC heating current. This approach not only eliminates the need for complex pulse generation and control circuitry, reducing system design complexity and cost, and improving battery life, but also avoids compatibility issues such as electromagnetic interference caused by the transient surge of the pulse current, which can affect the normal operation of surrounding electronic devices. Furthermore, this method is simple to control and implement, and does not require the addition of new components, making it suitable for active balanced energy storage parallel systems.

[0033] Described below Figure 1 How to perform the steps shown.

[0034] First, for step 100, the voltage of the embedded capacitor is regulated and controlled according to the regulated current of the auxiliary power supply electrically connected to the input terminal of the embedded capacitor of the active balanced energy storage parallel system, so that the embedded capacitor is in a stable voltage state.

[0035] like Figure 2 As shown, it is a circuit diagram of an active balancing energy storage parallel system provided by an embodiment of the present invention. The active balancing energy storage parallel system improves the topology on the basis of the centralized energy storage converter, and only adds a small-capacity, low-cost embedded converter to connect different battery clusters, thereby forming a series-parallel current regulation. It has the following advantages: 1. The embedded converter only needs to transmit part of the battery charge and discharge power, which still ensures a small number of devices; 2. The embedded converter adopts a non-isolated structure, and realizes the voltage stability of the embedded capacitor through energy balance control, saving the isolation transformer. Therefore, the embedded converter increases the power density and reduces the cost on the basis of realizing the parallel circulation suppression and active regulation of the charge and discharge current between each battery cluster.

[0036] Furthermore, when the battery needs to be heated, the energy storage converter (PCS) is in an inoperative state. At this time, the embedded capacitor input terminal is switched to the auxiliary power supply and the input half-bridge is normally open. Its topology is as follows: Figure 3 The size of the auxiliary power supply is determined by the design value of the embedded capacitor voltage. When calculating the main circuit parameters, the embedded capacitor voltage is 133V, and the margin is considered to be 1.5 to 2 times, so this design selects a 200V auxiliary power supply.

[0037] Since the embodiment of the present invention generates a heating current by applying an excitation signal across the half-bridge switch of the active balanced energy storage parallel system, and the generation of the heating current is not only related to the half-bridge switch function, but also to the embedded capacitor voltage, the stability of the embedded capacitor voltage is a prerequisite for generating the excitation voltage.

[0038] Therefore, an embodiment of the present invention controls the voltage of the embedded capacitor by adjusting the current of the auxiliary power supply, including the following steps: calculating a time-domain expression for the voltage of the embedded capacitor based on the average current of the auxiliary power supply, the average switching function of the half-bridge switch, and the average charge and discharge current of the branch battery; and performing a Laplace transform on the voltage time-domain expression to obtain a regulated current of the auxiliary power supply for regulating the voltage of the embedded capacitor.

[0039] Specifically, first establish the time domain expression of the embedded capacitor voltage using the following formula:

[0040]

[0041] Where C sc is the capacitance value of the embedded capacitor; T is the mean value of the variable; <V sc (t)> T is the average voltage of the embedded capacitor,<I(t)> T is the average value of auxiliary power supply current, j1 (t)> T is the average value of the half-bridge switching function on the jth battery side, j (t)> T is the average value of the charge and discharge current of the jth battery.

[0042] Furthermore, the design Figure 4 The auxiliary power current controller shown is used to regulate the voltage of the embedded capacitor. The regulated current is calculated by the following formula:

[0043]

[0044] Where, I(s) is the regulated current of the auxiliary power supply; K P K is the proportional control coefficient of the embedded capacitor voltage; I is the integral control coefficient of the embedded capacitor voltage; is the small signal value of the embedded capacitor voltage; is the reference value of the unsteady-state voltage of the embedded capacitor; I is the steady-state current of the auxiliary power supply; C sc is the capacitance of the embedded capacitor; s is the Laplace operator.

[0045] ​​With respect to step 102 , when the embedded capacitor is in a voltage-stabilizing state, a heating current for heating the battery in each branch is generated according to an excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system.

[0046] In an embodiment of the present invention, the heating current is generated by the following steps: establishing a time domain expression of the excitation voltage generated by the excitation signal based on the signal parameters of the excitation signal and the voltage of the embedded capacitor; establishing a time domain expression of the heating current generated by the excitation signal based on the time domain expression of the excitation voltage and the open circuit voltage of the branch battery; solving and calculating the time domain expression of the heating current, and establishing a specific expression of the heating current based on the voltage of the embedded capacitor in a steady-state state; determining an influencing parameter based on the specific expression of the heating current, and adjusting the excitation signal based on the influencing parameter to generate a heating current for heating each branch battery.

[0047] Specifically, when the actual excitation signal is given, the generated AC excitation voltage is:

[0048] V cj (t) = V sc ×Asin(ωt+ψ j )

[0049] Where V sc is the stable voltage of the embedded capacitor; A is the amplitude of the excitation signal; ω is the angular frequency of the excitation signal, ψ j is the phase of the jth excitation signal; V cj (t) is the excitation voltage generated by the j-th excitation signal at time t.

[0050] The corresponding time domain expression of the heating current is established by the following formula:

[0051]

[0052] Where, I j is the heating current generated by the jth excitation signal; r is the internal resistance of the battery; L is the battery filter inductance; V OCVj is the open circuit voltage of the battery.

[0053] By solving the above formula, the specific expression of heating current can be obtained as follows:

[0054]

[0055] Where i j (t) is the specific value of heating current; V = V sc ×A; ω = 2 × π × f, f is the frequency of the excitation signal; n is the total number of excitation signals.

[0056] It is worth noting that to ensure the safety and effectiveness of battery heating, for the case of multiple branches, the excitation signal applied to each branch needs to have a phase difference. Taking three clusters as an example, the specific expression of the heating current can be obtained:

[0057]

[0058] For n clusters of branches, n excitation signals are required, where the heating current generated by the jth excitation signal is:

[0059]

[0060] Where j = 1, 2, 3,…, n.

[0061] By comparing the coefficients, we can see that the second term is dominant, and the above formula can be simplified as:

[0062]

[0063] Corresponding:

[0064]

[0065] It can be determined that the heating current is related to the frequency and amplitude of the excitation signal. In the variable AC battery heating system, the frequency and amplitude of the heating current are usually obtained by nonlinear programming. However, in the present invention, no optimal solution is performed, and only a heating current with controllable frequency and amplitude is designed. Additional constraint adjustments are required, including the maximum current allowed by the IGBT selection.

[0066] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0067] MATLAB / Simulink software was used to build a preferred topology of an embedded converter for energy storage as shown in the figure. Simulation verification was performed on the topology. The simulation parameters are shown in Table 1 below:

[0068] Table 1

[0069]

[0070] Figure 5 The voltage of the built-in converter can achieve energy balance. Figure 6 When the excitation signal has an amplitude of 0.2 and a frequency of 100 Hz, the Simulink simulation waveform of the heating current of branch 1 and the calculated current 1 function waveform are shown. It can be seen from the waveforms that the two completely overlap, proving the correctness of the established current model. Figure 7is the excitation signal waveform. The amplitude and frequency of the excitation signal are continuously changing. The excitation signal is turned on at 0.05s. The excitation signal amplitude is 0.1 and the frequency is 50 from 0.05 to 0.2. The excitation signal amplitude is 0.2 and the frequency is 50 from 0.2 to 0.3. The excitation signal amplitude is 0.2 and the frequency is 50 from 0.3 to 0.4. The excitation signal amplitude is 0.2 and the frequency is 100 from 0.4 to 0.5. The excitation signal amplitude is 0.3 and the frequency is 100 from 0.5 to 0.55. The excitation signal is stopped. Figure 8 is the AC heating current, and the heating current changes with the excitation signal. It can be seen that the heating current is related to the amplitude and frequency of the excitation signal.

[0071] The above examples prove that the variable current control method of the active balanced energy storage parallel system implemented in this example is feasible and effective, and can achieve continuous control of the heating current frequency and amplitude.

[0072] Please refer to Figure 9 , an embodiment of the present invention provides a battery heating device for an active balanced energy storage parallel system, the device comprising:

[0073] A control module 900 is configured to regulate and control the voltage of the embedded capacitor according to a regulated current of an auxiliary power supply electrically connected to an input terminal of the embedded capacitor of the active balanced energy storage parallel system, so as to keep the embedded capacitor in a voltage-regulated state;

[0074] The generating module 902 is configured to generate a heating current for heating the battery in each branch according to the excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system when the embedded capacitor is in a voltage-stabilized state.

[0075] In an embodiment of the present invention, the voltage of the embedded capacitor is regulated and controlled according to the regulated current of the auxiliary power supply electrically connected to the input terminal of the embedded capacitor of the active balanced energy storage parallel system, including:

[0076] Calculating a time-domain expression of the voltage of the embedded capacitor according to the average current of the auxiliary power supply, the average switching function of the half-bridge switch, and the average charge and discharge current of the branch battery;

[0077] The voltage time-domain expression is subjected to Laplace transformation to obtain a regulation current of an auxiliary power supply for regulating the voltage of the embedded capacitor.

[0078] In the embodiment of the present invention, the voltage time domain expression is established by the following formula:

[0079]

[0080] Where C sc is the capacitance value of the embedded capacitor; T is the mean value of the variable; <V sc(t)> T is the average voltage of the embedded capacitor,<I(t)> T is the average value of auxiliary power supply current, j1 (t)> T is the average value of the half-bridge switching function on the jth battery side, j (t)> T is the average value of the charge and discharge current of the jth battery.

[0081] In the embodiment of the present invention, the regulating current is calculated by the following formula:

[0082]

[0083] Where, I(s) is the regulated current of the auxiliary power supply; K P K is the proportional control coefficient of the embedded capacitor voltage; I is the integral control coefficient of the embedded capacitor voltage; is the small signal value of the embedded capacitor voltage; is the reference value of the unsteady-state voltage of the embedded capacitor; I is the steady-state current of the auxiliary power supply; C sc is the capacitance of the embedded capacitor; s is the Laplace operator.

[0084] In an embodiment of the present invention, the method of generating a heating current for heating each branch battery based on the excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system includes: establishing a time domain expression of the excitation voltage generated by the excitation signal based on the signal parameters of the excitation signal and the voltage of the embedded capacitor; establishing a time domain expression of the heating current generated by the excitation signal based on the time domain expression of the excitation voltage and the open circuit voltage of the branch battery; solving and calculating the time domain expression of the heating current, and establishing a specific expression of the heating current based on the voltage of the embedded capacitor in a voltage-stabilizing state; determining an influencing parameter based on the specific expression of the heating current, and adjusting the excitation signal based on the influencing parameter to generate a heating current for heating each branch battery.

[0085] In the embodiment of the present invention, the time domain expression of the excitation voltage is established by the following formula:

[0086] V cj (t) = V sc ×Asin(ωt+ψ j )

[0087] Where V sc is the stable voltage of the embedded capacitor; A is the amplitude of the excitation signal; ω is the angular frequency of the excitation signal, ψ j is the phase of the jth excitation signal; V cj ​​(t) is the excitation voltage generated by the j-th excitation signal at time t.

[0088] In the embodiment of the present invention, the time domain expression of the heating current is established by the following formula:

[0089]

[0090] Where, I j is the heating current generated by the jth excitation signal; r is the internal resistance of the battery; L is the battery filter inductance; V OCVj is the open circuit voltage of the battery.

[0091] In the embodiment of the present invention, the specific expression of the heating current is established by the following formula:

[0092]

[0093] Where i j (t) is the specific value of heating current; V = V sc ×A; ω = 2 × π × f, f is the frequency of the excitation signal; n is the total number of excitation signals.

[0094] It should be noted that the battery heating device for the active balancing energy storage parallel system provided in the above embodiment is merely exemplified by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the battery heating device for the active balancing energy storage parallel system provided in the above embodiment and the battery heating method and device embodiment of the active balancing energy storage parallel system are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0095] The embodiment of the present application also provides a computer device, please refer to Figure 10 The computer device includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set, or instruction set, and the at least one instruction, at least one program, code set, or instruction set is loaded and executed by the processor to implement the battery heating method and device for the active balancing energy storage parallel system provided by the above-mentioned method embodiments.

[0096] An embodiment of the present application also provides a computer-readable storage medium, on which is stored at least one instruction, at least one program, code set, or instruction set, which is loaded and executed by a processor to implement the battery heating method and device for the active balancing energy storage parallel system provided by the above-mentioned method embodiments.

[0097] An embodiment of the present application further provides a computer program product, which includes a computer program. A processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes the battery heating method and device of the active balancing energy storage parallel system described in any of the above embodiments.

[0098] For the convenience of description, the above systems or devices are described as being divided into various modules or units according to their functions. Of course, when implementing this application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0099] Through the description of the above embodiments, it can be seen that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present application or certain parts of the embodiments.

[0100] Finally, it should be noted that, in this document, relational terms such as first, second, third, and fourth are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0101] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A battery heating method for an active balanced energy storage parallel system, characterized in that: The method comprises: Regulating and controlling the voltage of the embedded capacitor according to the regulated current of the auxiliary power supply electrically connected to the input terminal of the embedded capacitor of the active balanced energy storage parallel system, so that the embedded capacitor is in a voltage-stabilized state; When the embedded capacitor is in a voltage-stabilizing state, a heating current for heating the battery in each branch is generated according to the excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system.

2. The method according to claim 1, wherein The step of regulating and controlling the voltage of the embedded capacitor according to the regulated current of the auxiliary power supply electrically connected to the input terminal of the embedded capacitor of the active balanced energy storage parallel system includes: Calculating a time-domain expression of the voltage of the embedded capacitor according to the average current of the auxiliary power supply, the average switching function of the half-bridge switch, and the average charge and discharge current of the branch battery; The voltage time-domain expression is subjected to Laplace transformation to obtain a regulation current of an auxiliary power supply for regulating the voltage of the embedded capacitor.

3. The method according to claim 2, wherein The voltage time domain expression is established by the following formula: Where C sc is the capacitance value of the embedded capacitor; T is the mean value of the variable; <V sc (t)> T is the average voltage of the embedded capacitor,<I(t)> T is the average value of auxiliary power supply current, j1 (t)> T is the average value of the half-bridge switching function on the jth battery side, j (t)> T is the average value of the charge and discharge current of the jth battery.​​ 4. The method according to claim 2, wherein The regulating current is calculated by the following formula: Where, I(s) is the regulated current of the auxiliary power supply; K P K is the proportional control coefficient of the embedded capacitor voltage; I is the integral control coefficient of the embedded capacitor voltage; is the small signal value of the embedded capacitor voltage; is the reference value of the unsteady-state value of the built-in capacitor voltage; I is the steady-state current of the auxiliary power supply; C sc is the capacitance value of the embedded capacitor; s is the Laplace operator.

5. The method according to claim 1, wherein The step of generating a heating current for heating the battery in each branch according to the excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system comprises: Establishing a time-domain expression of an excitation voltage generated by the excitation signal according to signal parameters of the excitation signal and the voltage of the embedded capacitor; Establishing a time-domain expression for the heating current generated by the excitation signal according to the time-domain expression for the excitation voltage and the open-circuit voltage of the branch battery; Solving and calculating the time domain expression of the heating current, and establishing a specific expression of the heating current according to the voltage of the embedded capacitor in the voltage stabilization state; An influencing parameter is determined according to a specific expression of the heating current, and the excitation signal is adjusted according to the influencing parameter to generate a heating current for heating each branch battery.

6. The method according to claim 5, wherein The time domain expression of the excitation voltage is established by the following formula: V cj (t)=V sc ×Asin(ωt+ψ j ) Where V sc is the stable voltage of the embedded capacitor; A is the amplitude of the excitation signal; ω is the angular frequency of the excitation signal, ψ j is the phase of the jth excitation signal; V cj (t) is the excitation voltage generated by the j-th excitation signal at time t.

7. The method according to claim 6, wherein The time domain expression of the heating current is established by the following formula: Where, I j is the heating current generated by the jth excitation signal; r is the internal resistance of the battery; L is the battery filter inductance; V OCVj is the open circuit voltage of the battery.

8. The method according to claim 7, wherein The specific expression of the heating current is established by the following formula: Where i j (t) is the specific value of heating current; V = V sc ×A; ω = 2 × π × f, f is the frequency of the excitation signal; n is the total number of excitation signals.

9. A battery heating device for an active balanced energy storage parallel system, characterized in that: The device comprises: A control module, configured to regulate and control the voltage of the embedded capacitor according to a regulated current of an auxiliary power supply electrically connected to an input terminal of the embedded capacitor of the active balanced energy storage parallel system, so as to keep the embedded capacitor in a voltage-stabilized state; A generating module is used to generate a heating current for heating the battery of each branch according to the excitation signal applied to both sides of the half-bridge switch of each branch of the active balanced energy storage parallel system when the embedded capacitor is in a voltage-stabilized state.

10. A computer device, characterized in that: The computer device includes a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of any one of the methods described in claims 1-8.

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