Energy storage battery temperature control method and energy storage system

Abstract

The invention relates to an energy storage battery temperature control method and an energy storage system.The method is used for the energy storage system, the energy storage system comprises an inversion module and further comprises a battery connected with the inversion module, and the method comprises the steps that S1, under the condition that the battery cell temperature of the battery meets a first condition, the battery cell temperature of the battery meets the first condition; pushing an option whether to start self-heating or temperature keeping to the user; s2, if it is received that the user selects to start the self-heating mode, an instruction is sent to the battery to enter the self-heating mode; and S3, the battery receives the self-heating instruction, and requests the inversion module to charge and discharge under the condition that the battery cell temperature of the battery meets a second condition, so that the conversion between the low-temperature self-heating mode and the temperature maintaining mode of the battery is realized. According to the scheme provided by the invention, the problem that the energy storage lithium ion battery cannot be charged at the temperature below zero DEG C can be solved, and the temperature of the battery cell can be kept in a proper temperature interval of more than 2 DEG C.

Description

Technical Field

[0001] The present invention relates to the technical field of battery thermal management, and in particular to a temperature control method for an energy storage battery and an energy storage system. Background Art

[0002] Currently, lithium-ion batteries used in the energy storage industry are limited by their cells and cannot be charged below zero degrees Celsius. This means that if lithium-ion batteries are charged below zero degrees Celsius, lithium will be deposited, affecting battery life and safety. However, in some cold regions, such as the modular regions of Europe and North America, users have an urgent need to charge and use lithium-ion batteries during the winter.

[0003] Existing lithium-ion batteries for energy storage use a "heating film" method. This is relatively expensive and can easily lead to defects such as "poor temperature field consistency" during heating. This not only creates a poor user experience for end users but also increases the cost of the energy storage system. To address these technical shortcomings, this application proposes a temperature control method for energy storage batteries and an energy storage system. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: how to design a temperature control solution for the battery core of an energy storage battery, which can solve the problem that the energy storage lithium-ion battery cannot be charged below zero degrees Celsius.

[0005] In a first aspect, an embodiment of the present invention provides a method for controlling the temperature of an energy storage battery. The method is used in an energy storage system, wherein the energy storage system includes an inverter module and a battery connected to the inverter module. The method includes: S1, when the battery cell temperature meets a first condition, pushing an option of whether to turn on self-heating or temperature maintenance to the user; S2, if the user selects to turn on the self-heating mode, sending an instruction to the battery to enter the self-heating mode; S3, the battery receives the self-heating instruction and, when the battery cell temperature meets a second condition, requests charging and discharging from the inverter module, thereby achieving a transition between the battery's low-temperature self-heating mode and the temperature maintenance mode. In the above scheme, when the battery cell temperature meets the first condition and meets the second condition, the logic of the first and second conditions is opposite; for example, if the first condition is met, it belongs to situation A, and if the situation A is not met, it belongs to the second condition; that is, when the battery cell temperature does not meet the first condition but meets the second condition, charging and discharging is requested from the inverter module.

[0006] A further technical solution is that, when the battery cell temperature meets the first condition, S1 pushes to the user the option of whether to turn on self-heating or temperature maintenance, including: S11, obtaining the battery cell temperature, and if the battery cell temperature is lower than the first temperature Ta, pushing to the user via a remote server the option of whether to turn on self-heating or temperature maintenance. Furthermore, if the battery cell temperature is not lower than the first temperature Ta, the status quo is maintained. In the above solution, the user can choose whether to turn on the self-heating mode and the temperature maintenance mode on the mobile phone or PC, and the self-heating mode and the temperature maintenance mode are in a two-choice logical relationship.

[0007] Its further technical solution is that, when the battery cell temperature meets the first condition, S2 pushes to the user the option of whether to turn on self-heating or temperature maintenance, including: S21, if the user chooses to turn on the self-heating mode, the inverter module determines whether it is in a grid-connected state, and if it is in a grid-connected state, sends an instruction to the battery to enter the self-heating mode.

[0008] Its further technical solution is that the step S3 includes: S31, the battery receives a self-heating instruction, first judges the current battery cell temperature, and if the temperature is greater than the first temperature Ta, requests the inverter module to charge and discharge until the SOC is greater than or equal to the first percentage value A; S32, when it is detected that the battery cell temperature meets the third condition, first converts to discharging and then continues charging; S33, when it is detected that the battery cell temperature meets the fourth condition, first converts to discharging and then continues charging; S34, when it is detected that the battery cell temperature meets the fifth condition, first converts to discharging and then continues charging.

[0009] Its further technical solution is that the first temperature Ta is less than the second temperature Tb; the step of S32 includes: S302, when it is detected that the battery cell temperature is between the first temperature Ta and the second temperature Tb and the battery SOC is greater than or equal to the first percentage value A, requesting discharge from the inverter module, when the battery cell temperature is greater than or equal to the first temperature Ta after discharge, requesting the inverter module to charge the battery, and when the battery cell temperature is greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, when both conditions are met, exiting the self-heating mode. Furthermore, if the temperature does not reach the first temperature Ta during the discharge process and the battery SOC is less than or equal to the fourth percentage value D, the battery enters a dormant state; when in the self-heating mode, if the heating does not reach the preset temperature Te, the battery enters a temperature holding state, so that the battery cell temperature is maintained above the first temperature Ta, and can be charged at any time to store energy. In the above solution, the discharge energy during the self-heating process can be provided to the load or sold to the power grid, creating income for users.

[0010] A further technical solution is that the second temperature Tb is less than the third temperature Tc; the step S33 includes: S303, when it is detected that the battery cell temperature is between the second temperature Tb and the third temperature Tc and the battery SOC is greater than or equal to the second percentage value B, requesting discharge from the inverter module; when the battery cell temperature is greater than or equal to the first temperature Ta after discharge, requesting the inverter module to charge the battery; when the battery cell temperature is greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, if both conditions are met, exiting the self-heating mode. Furthermore, if the temperature does not reach the first temperature Ta during discharge and the battery SOC is less than or equal to the fourth percentage value D, the battery enters a dormant state.

[0011] Its further technical solution is that the third temperature Tc is less than the fourth temperature Td; the step S34 includes: S304, when it is detected that the battery cell temperature is between the third temperature Tc and the fourth temperature Td and the battery SOC is greater than or equal to the third percentage value C, requesting discharge from the inverter module; when the battery cell temperature is greater than or equal to the first temperature Ta after discharge, requesting the inverter module to charge the battery; when the battery cell temperature is greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, when both conditions are met, exiting the self-heating mode. Furthermore, when in the self-heating mode, if the heating does not reach the preset temperature Te, the temperature maintenance state is entered to maintain the battery cell temperature above the first temperature Ta, so that charging and energy storage can be carried out at any time.

[0012] A further technical solution is that the method further includes: if the battery cell temperature drops below a preset temperature Te, entering a temperature holding state to maintain the battery cell temperature above a first temperature Ta, thereby maintaining the battery cell in a ready-to-charge state and storing energy. In one embodiment, if the battery cell temperature drops from a second temperature Tb to below the preset temperature Te, the battery cell temperature ultimately remains no lower than the value of the first temperature Ta.

[0013] In a second aspect, the present invention provides an energy storage system comprising a battery, configured to implement the energy storage battery temperature control method described in the first aspect. The technical effect of the energy storage system is to resolve the problem of lithium-ion batteries being unable to charge at temperatures below zero degrees Celsius.

[0014] In summary, the current energy storage lithium-ion batteries in the energy storage industry are limited by the battery cells and do not support charging below zero degrees Celsius. In other words, if the lithium-ion battery is charged below zero degrees Celsius, lithium will be deposited, affecting the battery life and safety. However, in some low-temperature areas in winter, users will have an urgent need to charge and use the energy storage lithium-ion batteries, such as the modular areas of Europe and the modular areas of North America. Based on this, the energy storage battery temperature control method and energy storage system described in this application can not only solve the problem of energy storage lithium-ion batteries not being able to charge below zero degrees Celsius, but also maintain the battery cell temperature in a suitable temperature range above two degrees Celsius. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0016] 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A flow chart of a method for controlling the temperature of an energy storage battery provided in an embodiment of the present invention.

[0018] Figure 2 Another flow chart of the energy storage battery temperature control method provided by an embodiment of the present invention.

[0019] Figure 3 A schematic diagram of a framework of an energy storage system provided in an embodiment of the present invention.

[0020] Figure 4 A logical diagram of an energy storage system provided in an embodiment of the present invention.

[0021] Figure 5 Another logical schematic diagram of the energy storage system provided by an embodiment of the present invention.

[0022] Figure 6 A simplified schematic diagram of the electronic device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] It will be understood that when used in this specification and the appended claims, the terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or other features, integers, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should be further understood that the term "and / or" used in the present description and the appended claims refers to one or any combination and all possible combinations of the associated listed items, and includes these combinations.

[0027] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0028] In this specification and the appended claims, there may be multiple ways of expressing the same technical feature or professional term, such as adopting different forms of expression such as superordinate generalization, subordinate limitation or synonym replacement; those skilled in the art can clearly understand the essentially same technical meaning pointed to by different ways of expression based on their professional knowledge and in combination with the overall content of the specification and the drawings; the differences between different ways of expression are only reflected in the diversity at the textual level, and do not constitute a substantial modification or restriction of the technical solution, and will not affect the certainty of the scope of protection of the claims of this patent and the full disclosure of the technical content of the specification.

[0029] Example 1

[0030] See also Figures 1 to 5As shown, a temperature control method for an energy storage battery proposed in an embodiment of the present invention is used in an energy storage system, wherein the energy storage system includes an inverter module and a battery connected to the inverter module. The method includes: S1, when the battery cell temperature meets the first condition, pushing the option of whether to turn on self-heating or temperature maintenance to the user; S2, if the user selects to turn on the self-heating mode, sending an instruction to the battery to enter the self-heating mode; S3, the battery receives the self-heating instruction, and when the battery cell temperature meets the second condition, requests charging and discharging from the inverter module, thereby realizing the conversion between the low-temperature self-heating mode and the temperature maintenance mode of the battery. In the above scheme, when the battery cell temperature meets the first condition and the second condition, the logic of the first condition and the second condition is opposite; for example, if the first condition is met, it belongs to situation A, and if it does not meet situation A, it belongs to the second condition; that is, when the battery cell temperature does not meet the first condition but meets the second condition, charging and discharging is requested from the inverter module. Among them, the option of whether to turn on self-heating or temperature maintenance is pushed to the user, which can be pushed to the user, or set by the user himself in the APP or the user himself on the WEB.

[0031] In one embodiment, the S1, when the battery cell temperature meets the first condition, pushes the option of whether to turn on self-heating or temperature maintenance to the user, including: S11, obtaining the battery cell temperature, if the battery cell temperature is lower than the first temperature Ta, pushing the option of whether to turn on self-heating or temperature maintenance to the user through a remote server. Furthermore, if the battery cell temperature is not lower than the first temperature Ta, the status quo is maintained. In the above scheme, the user can choose whether to turn on the self-heating mode and the temperature maintenance mode on the mobile phone or PC, and the self-heating mode and the temperature maintenance mode are in a logical relationship of choosing one from the other. Among them, in the scenario of pushing to the user, the way to obtain the battery cell temperature is that the inverter module detects the battery cell temperature; if the user sets it himself on the APP or WEB, the inverter module does not detect the battery temperature.

[0032] In one embodiment, S2, when the battery cell temperature meets the first condition, pushes to the user the option of whether to turn on self-heating or temperature maintenance, including: S21, if the user chooses to turn on the self-heating mode, the inverter module determines whether it is in a grid-connected state, and if it is in a grid-connected state, sends an instruction to the battery to enter the self-heating mode.

[0033] In one embodiment, the step S3 includes: S31, the battery receives a self-heating instruction, first judges the current battery cell temperature, and if the temperature is greater than the first temperature Ta, requests the inverter module to charge and discharge until the SOC is greater than or equal to the first percentage value A; S32, when it is detected that the battery cell temperature meets the third condition, first changes to discharging and then continues charging; S33, when it is detected that the battery cell temperature meets the fourth condition, first changes to discharging and then continues charging; S34, when it is detected that the battery cell temperature meets the fifth condition, first changes to discharging and then continues charging.

[0034] In one embodiment, the first temperature Ta is less than the second temperature Tb; the step S32 includes: S302, when it is detected that the battery cell temperature is between the first temperature Ta and the second temperature Tb and the battery SOC is greater than or equal to the first percentage value A, requesting discharge from the inverter module; when the battery cell temperature is greater than or equal to the first temperature Ta after discharge, requesting the inverter module to charge the battery; when the battery cell temperature is greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, when both conditions are met, exiting the self-heating mode. Furthermore, if the temperature does not reach the first temperature Ta during discharge and the battery SOC is less than or equal to the fourth percentage value D, the battery enters a dormant state; when in the self-heating mode, if the heating does not reach the preset temperature Te, the battery enters a temperature holding state, so that the battery cell temperature is maintained above the first temperature Ta, and can be charged at any time to store energy. In the above scheme, the discharge energy during the self-heating process can be provided to the load or sold to the power grid, creating revenue for users.

[0035] In one embodiment, the second temperature Tb is less than the third temperature Tc; the step S33 includes: S303, when it is detected that the battery cell temperature is between the second temperature Tb and the third temperature Tc and the battery SOC is greater than or equal to a second percentage value B, requesting discharge from the inverter module; when the battery cell temperature is greater than or equal to the first temperature Ta after discharge, requesting the inverter module to charge the battery; when the battery cell temperature is greater than or equal to the SOC before self-heating and the temperature is greater than or equal to a preset temperature Te, and both conditions are met, exiting the self-heating mode. Furthermore, if the temperature does not reach the first temperature Ta during discharge and the battery SOC is less than or equal to a fourth percentage value D, the battery enters a dormant state.

[0036] In one embodiment, the third temperature Tc is less than the fourth temperature Td; the step S34 includes: S304, when it is detected that the battery cell temperature is between the third temperature Tc and the fourth temperature Td and the battery SOC is greater than or equal to a third percentage value C, requesting discharge from the inverter module; when the battery cell temperature is greater than or equal to the first temperature Ta after discharge, requesting the inverter module to charge the battery; when the battery cell temperature is greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, and both conditions are met, exiting the self-heating mode. Furthermore, when in the self-heating mode, if the heating does not reach the preset temperature Te, entering the temperature holding state, so that the battery cell temperature is maintained above the first temperature Ta, and can be charged at any time to store energy.

[0037] In one embodiment, the method further includes: if the battery cell temperature drops below a preset temperature Te, entering a temperature holding state to maintain the battery cell temperature above a first temperature Ta, thereby maintaining the battery cell temperature in a ready-to-charge state and storing energy. In one embodiment, if the battery cell temperature drops from a second temperature Tb to below the preset temperature Te, the battery cell temperature ultimately remains at or above the value of the first temperature Ta.

[0038] In one embodiment, the present invention provides an energy storage system comprising a battery. The energy storage system is configured to implement the energy storage battery temperature control method described in the above embodiment. The technical effect of the energy storage system is to resolve the problem of lithium-ion batteries being unable to charge at temperatures below zero degrees Celsius.

[0039] In summary, the current energy storage lithium-ion batteries in the energy storage industry are limited by the battery cells and do not support charging below zero degrees Celsius. In other words, if the lithium-ion battery is charged below zero degrees Celsius, lithium will be deposited, affecting the battery life and safety. However, in some low-temperature areas in winter, users will have an urgent need to charge and use the energy storage lithium-ion batteries, such as the modular areas of Europe and the modular areas of North America. Based on this, the energy storage battery temperature control method and energy storage system described in this application can not only solve the problem of energy storage lithium-ion batteries not being able to charge below zero degrees Celsius, but also maintain the battery cell temperature in a suitable temperature range above two degrees Celsius.

[0040] Example 2

[0041] See also Figure 4 , Figure 4This is a block diagram of an electronic device provided by the present invention. This electronic device can be a terminal or a server. A terminal can be a smartphone, tablet computer, laptop computer, desktop computer, personal digital assistant, wearable device, or other electronic device with communication capabilities. The device includes a processor 111, a communication interface 112, a memory 113, and a communication bus 114. The processor 111, communication interface 112, and memory 113 communicate with each other via the communication bus 114.

[0042] The memory 113 is used to store computer programs.

[0043] In one embodiment of the present invention, the processor 111 is configured to implement the method provided by any one of the aforementioned method embodiments when executing a program stored in the memory 113 .

[0044] It should be understood that in the embodiment of the present application, the processor 111 may be a central processing unit (CPU), and the processor 502 may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0045] Those skilled in the art will appreciate that all or part of the steps in the method of the above-described embodiment can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. The computer program is executed by at least one processor in the computer system to implement the steps in the method of the above-described embodiment.

[0046] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions, but such implementation should not be considered to be beyond the scope of the present invention.

[0047] In the several embodiments provided herein, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the various units is merely a logical functional division, and actual implementation may employ other division methods. For example, units or components may be combined or integrated into another system, or some features may be omitted or not implemented.

[0048] The steps in the methods of the embodiments of the present invention may be adjusted in order, combined, or deleted as needed. The units in the devices of the embodiments of the present invention may be combined, divided, or deleted as needed. Furthermore, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit.

[0049] If this integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the existing technology, or all or part 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 a number of instructions for causing a computer device (which can be a personal computer, terminal, or network device, etc.) to execute all or part of the steps of the method described in various embodiments of the present invention.

[0050] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0051] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, to the extent such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to encompass such changes and modifications.

[0052] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A method for controlling the temperature of an energy storage battery, characterized in that: The method is used for an energy storage system, wherein the energy storage system includes an inverter module and a battery connected to the inverter module. The method includes: S1: When the battery cell temperature meets the first condition, the user is prompted with an option to enable self-heating or maintain temperature. S2, if the user selects to turn on the self-heating mode, a command is sent to the battery to enter the self-heating mode; S3, the battery receives the self-heating instruction, and when the battery cell temperature meets the second condition, requests charging and discharging from the inverter module, thereby realizing the conversion between the low-temperature self-heating mode and the temperature maintenance mode of the battery.

2. The energy storage battery temperature control method according to claim 1, characterized in that: The step S1, when the battery cell temperature meets the first condition, pushes to the user an option of whether to enable self-heating or temperature maintenance, including: S11, obtaining the battery cell temperature. If the battery cell temperature is lower than a first temperature Ta, a remote server is used to push an option to the user to enable self-heating or temperature maintenance.

3. The energy storage battery temperature control method according to claim 2, characterized in that: The step S2, when the battery cell temperature meets the first condition, pushes to the user an option of whether to enable self-heating or temperature maintenance, including: S21, if the user selects to start the self-heating mode, the inverter module determines whether it is in the grid-connected state. If it is in the grid-connected state, it sends a command to the battery to enter the self-heating mode.

4. The energy storage battery temperature control method according to claim 3, characterized in that: The steps of S3 include: S31, the battery receives a self-heating instruction and first determines the current cell temperature. If the temperature is greater than a first temperature Ta, the battery requests the inverter module to charge or discharge until the SOC is greater than or equal to a first percentage value A; S32, when it is detected that the battery cell temperature meets the third condition, first switching to discharge and then continuing to charge; S33, when it is detected that the battery cell temperature meets the fourth condition, first switching to discharge and then continuing to charge; S34, when it is detected that the battery cell temperature meets the fifth condition, the battery cell is first discharged and then charged.

5. The energy storage battery temperature control method according to claim 4, characterized in that: The first temperature Ta is lower than the second temperature Tb; the step S32 includes: S302, when it is detected that the battery cell temperature is between the first temperature Ta and the second temperature Tb and the battery SOC is greater than or equal to the first percentage value A, request discharge to the inverter module, when the battery cell temperature is greater than or equal to the first temperature Ta after discharge, request the inverter module to charge the battery, when the SOC is greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, when both conditions are met, exit the self-heating mode.

6. The energy storage battery temperature control method according to claim 5, characterized in that: The second temperature Tb is lower than the third temperature Tc; the step S33 includes: S303, when it is detected that the battery cell temperature is between the second temperature Tb and the third temperature Tc and the battery SOC is greater than or equal to the second percentage value B, request discharge to the inverter module, when the battery cell temperature is discharged to be greater than or equal to the first temperature Ta, request the inverter module to charge the battery, when the SOC is charged to be greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, if both conditions are met, exit the self-heating mode.

7. The energy storage battery temperature control method according to claim 6, characterized in that: The third temperature Tc is lower than the fourth temperature Td; the step S34 includes: S304: When it is detected that the battery cell temperature is between the third temperature Tc and the fourth temperature Td and the battery SOC is greater than or equal to the third percentage value C, discharge is requested to the inverter module. When the battery cell temperature is discharged to be greater than or equal to the first temperature Ta, the inverter module is requested to charge the battery. When the battery is charged to an SOC greater than or equal to the SOC before self-heating and the temperature is greater than or equal to the preset temperature Te, if both conditions are met, the self-heating mode is exited.

8. The energy storage battery temperature control method according to claim 7, characterized in that: The method further comprises: If the battery cell temperature drops below the preset temperature Te, the battery enters the temperature holding state, so that the battery cell temperature is maintained above the first temperature Ta, and the battery is in a charging state at any time to store energy.

9. An energy storage system, characterized in that: The energy storage system includes a battery therein, and the energy storage system is used to implement the energy storage battery temperature control method according to any one of claims 1 to 8.

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