Energy storage battery system

Abstract

The utility model relates to the technical field of batteries, and discloses an energy storage battery system which is composed of a lithium titanate battery pack, a lithium iron battery pack, a battery management system BMS, a pre-charging circuit, a DCDC circuit, a temperature control device, a first main positive relay, a first main negative relay, a second main negative relay, a third relay, a charging port and a discharging port. The overall performance, including environmental adaptability, stability, safety, service life and the like, of the battery system is improved, progress and development of the battery technology are promoted, and a more reliable, efficient and safe energy solution is provided for the fields of electric automobiles, energy storage systems and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an energy storage battery system. Background Art

[0002] With the continuous advancement of science and technology and the rapid development of lithium battery technology, the demand for lithium batteries in electric vehicles, energy storage systems and other fields has shown a significant growth trend. In order to meet this growing market demand, the types of lithium batteries have gradually diversified, aiming to determine the most suitable product type based on different customer needs and actual application scenarios. However, lithium batteries still face a series of challenges and limitations in practical applications.

[0003] First, the performance of lithium batteries is often significantly affected by temperature conditions. Excessively high temperatures may cause the charging and discharging performance of lithium batteries to decline, and even affect their service life and safety. Low temperatures, on the other hand, can cause lithium batteries to fail to function properly.

[0004] Secondly, differences in lithium battery material types will also limit the realization of its high-rate charge and discharge functions, thereby affecting its charge and discharge efficiency.

[0005] In addition, the service life of lithium batteries will be significantly reduced under extreme operating conditions such as overcharging and over-discharging, and may even cause serious safety problems such as thermal runaway of the battery pack.

[0006] Therefore, it is necessary to improve the existing technology.

[0007] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Utility Model Content

[0008] The utility model provides an energy storage battery system, aiming to solve the defects and shortcomings of existing lithium batteries in terms of performance, safety and reliability.

[0009] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0010] The utility model provides an energy storage battery system, including a lithium titanate battery pack, a lithium iron battery pack, a battery management system BMS, a pre-charging circuit, a DCDC circuit, a temperature control device, a first main positive relay, a first main negative relay, a second main negative relay, a third relay, a charging port and a discharging port; wherein,

[0011] The positive electrode of the iron-lithium battery pack is connected to the positive electrode of the charging port through the DCDC circuit, and the negative electrode of the iron-lithium battery pack is connected to the negative electrode of the charging port to form a first charging circuit; the positive electrode of the iron-lithium battery pack is connected to the positive electrode of the discharge port through the pre-charging circuit, and the negative electrode of the iron-lithium battery pack is connected to the negative electrode of the discharge port to form a first discharge circuit;

[0012] The positive electrode and negative electrode of the lithium titanate battery pack are respectively connected to the positive electrode and negative electrode of the charging port to form a second charging circuit; the positive electrode of the lithium titanate battery pack is connected to the positive electrode of the discharge port through the pre-charging circuit, and the negative electrode of the lithium titanate battery pack is connected to the negative electrode of the discharge port to form a second discharge circuit;

[0013] The positive electrode and negative electrode of the lithium titanate battery pack are respectively connected to the positive electrode and negative electrode of the lithium iron battery pack through a DCDC circuit;

[0014] The temperature control device is located inside the iron-lithium battery pack;

[0015] The first main positive relay is connected in series to the positive electrode of the charging port;

[0016] The first main negative relay is connected in series to the negative electrode of the lithium titanate battery pack;

[0017] The second main negative relay is connected in series to the negative electrode of the iron-lithium battery pack;

[0018] The third relay is connected in series between the positive electrode of the lithium titanate battery pack and the pre-charging circuit;

[0019] The temperature control device, the first main positive relay, the first main negative relay, the second main negative relay, the third relay, the DCDC circuit and the pre-charging circuit are respectively connected to the BMS.

[0020] Further, in the energy storage battery system, the pre-charging circuit includes a second main positive relay, a pre-charging relay and a pre-charging resistor;

[0021] The pre-charge relay is connected in series with the pre-charge resistor and then connected in parallel with the second main positive relay;

[0022] The second main positive relay and the pre-charge relay are connected to the BMS respectively.

[0023] Furthermore, the energy storage battery system further includes a first BMS acquisition board and a second BMS acquisition board;

[0024] The first BMS acquisition board is located in the lithium titanate battery pack and is connected to the battery cells in the lithium titanate battery pack;

[0025] The second BMS acquisition board is located in the iron-lithium battery pack and is connected to the battery cells in the iron-lithium battery pack;

[0026] The first BMS acquisition board and the second BMS acquisition board are respectively connected to the BMS;

[0027] The temperature control device is connected to the second BMS acquisition board.

[0028] Further, in the energy storage battery system, the temperature control device includes a heating device and a heat dissipation device;

[0029] The heating device and the heat dissipation device are respectively connected to the second BMS acquisition board.

[0030] Furthermore, in the energy storage battery system, the heating device is a heating film.

[0031] Furthermore, in the energy storage battery system, the heat dissipation device is a fan.

[0032] Furthermore, the energy storage battery system further includes a first insurance protection device;

[0033] The first fuse protection device is connected in series with the heating device.

[0034] Furthermore, the energy storage battery system also includes a second insurance protection device;

[0035] The negative electrode of the lithium titanate battery pack and the negative electrode of the lithium iron battery pack are respectively connected to the common negative electrode;

[0036] The second fuse protection device is connected in series to the common negative electrode.

[0037] Furthermore, the energy storage battery system also includes a third insurance protection device;

[0038] The third insurance protection device is connected in series between the negative electrode of the iron-lithium battery pack and the DCDC circuit.

[0039] Furthermore, in the energy storage battery system, the collection end of the first BMS collection board is connected to the battery cell in the lithium titanate battery pack;

[0040] The communication terminal of the first BMS acquisition board is connected to the BMS;

[0041] The power supply output end of the first BMS acquisition board is connected to the temperature control device through the BMS and the second BMS acquisition board.

[0042] Compared with the prior art, the utility model has the following beneficial effects:

[0043] The utility model provides an energy storage battery system, which consists of a lithium titanate battery pack, a lithium iron battery pack, a battery management system BMS, a pre-charging circuit, a DCDC circuit, a temperature control device, a first main positive relay, a first main negative relay, a second main negative relay, a third relay, a charging port and a discharging port. By performing specific circuit design, the overall performance of the battery system is improved, including environmental adaptability, stability, safety and service life, etc., which is conducive to promoting the progress and development of battery technology and providing more reliable, efficient and safe energy solutions for electric vehicles, energy storage systems and other fields.

[0044] The present invention has other characteristics and advantages, which will be apparent from the accompanying drawings and subsequent specific embodiments incorporated herein, or will be described in detail in the accompanying drawings and subsequent specific embodiments incorporated herein, which together are used to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 This is one of the circuit principle schematic diagrams of an energy storage battery system provided by an embodiment of the utility model;

[0047] Figure 2 This is the second circuit principle schematic diagram of an energy storage battery system provided by an embodiment of the utility model.

[0048] Reference numerals:

[0049] Lithium titanate battery pack 1, lithium iron battery pack 2, battery management system BMS 3, pre-charging circuit 4, DCDC circuit 5, temperature control device 6, first main positive relay 7, first main negative relay 8, second main negative relay 9, third relay 10, charging port 11, discharging port 12, first BMS acquisition board 13, second BMS acquisition board 14, first insurance protection device 15, second insurance protection device 16, third insurance protection device 17;

[0050] The second main positive relay 401, the pre-charge relay 402, the pre-charge resistor 403;

[0051] Heating device 601, heat dissipation device 602. DETAILED DESCRIPTION

[0052] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0053] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0054] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0055] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0056] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0057] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0058] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0059] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0060] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0061] Please refer to Figure 1-2 The embodiment of the utility model provides an energy storage battery system, including a lithium titanate battery pack 1, a lithium iron battery pack 2, a battery management system BMS 3, a pre-charging circuit 4, a DCDC circuit 5, a temperature control device 6, a first main positive relay 7, a first main negative relay 8, a second main negative relay 9, a third relay 10, a charging port 11 and a discharging port 12; wherein,

[0062] The positive electrode of the iron-lithium battery pack 2 is connected to the positive electrode of the charging port 11 through the DCDC circuit 5, and the negative electrode of the iron-lithium battery pack 2 is connected to the negative electrode of the charging port 11, forming a first charging circuit; the positive electrode of the iron-lithium battery pack 2 is connected to the positive electrode of the discharge port 12 through the pre-charging circuit 4, and the negative electrode of the iron-lithium battery pack 2 is connected to the negative electrode of the discharge port 12, forming a first discharge circuit;

[0063] The positive electrode and negative electrode of the lithium titanate battery pack 1 are respectively connected to the positive electrode and negative electrode of the charging port 11 to form a second charging circuit; the positive electrode of the lithium titanate battery pack 1 is connected to the positive electrode of the discharge port 12 through the pre-charging circuit 4, and the negative electrode of the lithium titanate battery pack 1 is connected to the negative electrode of the discharge port 12 to form a second discharge circuit;

[0064] The positive electrode and negative electrode of the lithium titanate battery pack 1 are also respectively connected to the positive electrode and negative electrode of the lithium iron battery pack 2 through the DCDC circuit 5;

[0065] When charging, lithium titanate battery pack 1 and lithium iron battery pack 2 can be charged synchronously. When discharging, only one discharges, and lithium iron battery pack 2 is discharged first. When discharging, lithium iron battery pack 2 is charged by lithium titanate battery pack 1 to ensure that lithium iron battery pack 2 is discharged first. When the temperature is abnormal, lithium titanate battery pack 1 works first, and after the temperature of lithium iron battery pack 2 is adjusted to the preset range, lithium iron battery pack 2 works first.

[0066] The temperature control device 6 is located in the iron-lithium battery pack 2, and is used to adjust the temperature of the iron-lithium battery pack 2 to ensure the temperature of the iron-lithium battery pack 2. Specifically, the temperature can be controlled and adjusted through the BMS 3. After the temperature of the iron-lithium battery pack 2 is adjusted to a preset range, charging and discharging are performed;

[0067] The first main positive relay 7 is connected in series to the positive electrode of the charging port 11 and is used to control different charging modes;

[0068] The first main negative relay 8 is connected in series to the negative electrode of the lithium titanate battery pack 1 and is used to control the connection and disconnection of the lithium titanate battery pack 1;

[0069] The second main negative relay 9 is connected in series to the negative electrode of the iron-lithium battery pack 2 and is used to control the connection and disconnection of the lithium battery pack 2;

[0070] The third relay 10 is connected in series between the positive electrode of the lithium titanate battery pack 1 and the pre-charging circuit 4, and is used to control the discharge of the lithium titanate battery pack 1;

[0071] The temperature control device 6, the first main positive relay 7, the first main negative relay 8, the second main negative relay 9, the third relay 10, the DCDC circuit 5 and the pre-charging circuit 4 are respectively connected to the BMS 3; the BMS 3 is used to control the normal operation of the entire battery system and ensure the safe use of the entire battery system.

[0072] It should be noted that, on the one hand, this embodiment utilizes the difference in performance between two different battery packs (i.e., lithium titanate battery pack 1 and lithium iron battery pack 2) to complement each other's advantages and disadvantages, thereby improving the overall performance of the battery system (including environmental adaptability, stability, safety and service life, etc.); on the other hand, by adding some devices and performing specific circuit design, the overall performance of the battery system is further improved.

[0073] Specifically, the lithium iron battery pack 2 has the characteristics of poor low-temperature performance (cannot be charged and discharged below zero degrees or can only be charged and discharged at a very small rate), low charge and discharge rate, and high safety performance. The lithium titanate battery pack 1 has good environmental adaptability, can be charged and discharged at minus 40°C, and has a high charge and discharge rate, can perform 6c charging and discharging, has high safety performance, and a low voltage platform.

[0074] In this embodiment, the pre-charging circuit 4 is a key component, which is used to pre-charge the battery pack before discharging. The design of the pre-charging circuit 4 ensures the safety and stability of the battery during the charging and discharging process.

[0075] Please refer again Figure 1-2 The pre-charging circuit 4 includes a second main positive relay 401, a pre-charging relay 402 and a pre-charging resistor 403; wherein,

[0076] The second main positive relay 401 is a control switch. When the BMS 3 determines that discharge is required, it controls the second main positive relay 401 to close, so that the current discharged by the battery pack can flow through the line where the second main positive relay 401 is located.

[0077] Pre-charge relay 402: It is also a control switch, but it is connected in series with the pre-charge resistor 403 and in parallel with the second main positive relay 401. In the initial stage of pre-charging, BMS 3 will first control the pre-charge relay 402 to close, while the second main positive relay 401 remains open. In this way, the current will first be limited by the pre-charge resistor 403 to achieve low-current pre-charging. When the pre-charging is completed, BMS 3 will control the pre-charge relay 402 to open, and the second main positive relay 401 to close, so that the battery pack can be discharged normally.

[0078] Pre-charge resistor 403: The main function of this resistor is to limit the current during pre-charge. The pre-charge resistor 403 is used to limit the current, thereby ensuring the safety and stability of the pre-charge process.

[0079] Please refer again Figure 1-2 In this embodiment, the energy storage battery system further includes a first BMS acquisition board 13 and a second BMS acquisition board 14;

[0080] The first BMS acquisition board 13 is located in the lithium titanate battery pack 1 and is connected to the battery cells in the lithium titanate battery pack 1. It is used to collect key parameters such as battery cell voltage and temperature of the lithium titanate battery pack 1 in real time, and transmit the data to the BMS 3 for processing and analysis;

[0081] The second BMS acquisition board 14 is located in the iron-lithium battery pack 2 and is connected to the battery cells in the iron-lithium battery pack 2. It is used to collect key parameters such as the battery cell voltage and temperature of the iron-lithium battery pack 2 in real time, and transmit the data to the BMS 3 for processing and analysis;

[0082] The first BMS acquisition board 13 and the second BMS acquisition board 14 are respectively connected to the BMS 3;

[0083] The temperature control device 6 is connected to the second BMS acquisition board 14 .

[0084] It should be noted that when the energy storage battery system starts to work, the first BMS acquisition board 13 and the second BMS acquisition board 14 respectively start to collect parameters such as voltage and temperature of the battery cells in their respective battery packs.

[0085] These data are centrally processed and analyzed by BMS 3, which determines the battery pack's charge and discharge status, health status, temperature, etc. based on these data, and adjusts the charge and discharge strategy accordingly to ensure the stability and safety of the battery system.

[0086] Specifically, when BMS 3 determines that the temperature of the iron-lithium battery pack 2 is too low, it will control the temperature control device 6 to heat the iron-lithium battery pack 2. When BMS 3 determines that the temperature of the iron-lithium battery pack 2 is too high, it will control the temperature control device 6 to dissipate heat from the iron-lithium battery pack 2.

[0087] In this embodiment, the temperature control device 6 plays a key role in ensuring that the iron-lithium battery pack 2 operates within a suitable temperature range, thereby improving the performance and safety of the battery pack. Figure 1-2 The temperature control device 6 includes a heating device 601 and a heat dissipation device 602, both of which are connected to the second BMS acquisition board 14 to achieve precise temperature control.

[0088] The heating device 601 is connected to the second BMS acquisition board 14, receives the heating instruction from the BMS 3, and adjusts the heating power according to the instruction.

[0089] The heating device 601 may be a heating film, which is a highly efficient heating element that can quickly and evenly transfer heat and is suitable for low-temperature heating of battery packs.

[0090] When the temperature of the lithium iron battery pack 2 is lower than the preset lower limit, the heating device 601 will start to release heat through the heating film to increase the temperature inside the battery pack, which helps to prevent the battery from performance degradation or damage in a low temperature environment.

[0091] The heat dissipation device 602 is also connected to the second BMS acquisition board 14, receives the heat dissipation instruction from the BMS 3, and adjusts the speed and wind direction of the fan according to the instruction.

[0092] The heat dissipation device 602 may be a fan. A fan is a common heat dissipation device that can remove heat by generating airflow to reduce the temperature inside the battery pack.

[0093] When the temperature of the lithium iron battery pack 2 is higher than the preset upper limit, the heat dissipation device 602 will start, and the airflow generated by the fan will take away the heat inside the battery pack to reduce the temperature. This helps prevent the battery from overheating in a high temperature environment, thereby improving the safety and stability of the battery.

[0094] Please refer again Figure 1-2In the embodiment, in order to improve the safety and reliability of the system, the system introduces a first insurance protection device 15, a second insurance protection device 16 and a third insurance protection device 17. These insurance protection devices play a key protective role at different positions, ensuring that the battery system can safely disconnect the circuit under abnormal conditions to prevent dangerous situations such as battery damage or fire.

[0095] The first insurance protection device 15:

[0096] Position: The first fuse protection device 15 is connected in series to the heating device 601 .

[0097] Function: When the heating device 601 is short-circuited, overloaded or in other abnormal situations, the first fuse protection device 15 can be quickly blown to cut off the circuit of the heating device 601 to prevent the heating device 601 from being damaged or causing a fire.

[0098] The second insurance protection device 16:

[0099] Position: The negative electrode of the lithium titanate battery pack 1 and the negative electrode of the lithium iron battery pack 2 are respectively connected to the common negative electrode, and the second insurance protection device 16 is connected in series to the common negative electrode.

[0100] Function: When a short circuit, overcurrent or other abnormal condition occurs in any of the lithium titanate battery packs 1 or the lithium iron battery pack 2, the second insurance protection device 16 can be quickly blown to cut off the circuit of the common negative electrode and ensure the safety of the main circuit of the entire battery system.

[0101] The third insurance protection device 17:

[0102] Position: The third insurance protection device 17 is connected in series between the negative electrode of the iron-lithium battery pack 2 and the DCDC circuit 5 .

[0103] Function: When the iron-lithium battery pack 2 discharges to the DCDC circuit 5, if a short circuit, overcurrent or other abnormal conditions occur, the third insurance protection device 17 can quickly blow, cutting off the circuit between the iron-lithium battery pack 2 and the DCDC circuit 5, preventing damage to the battery pack or the DCDC circuit 5, and protecting the safety of the entire system.

[0104] In this embodiment, the collection end of the first BMS collection board 13 is connected to the battery cell in the lithium titanate battery pack 1;

[0105] The communication terminal of the first BMS acquisition board 13 is connected to the BMS 3;

[0106] The power supply output end of the first BMS acquisition board 13 is connected to the temperature control device 6 through the BMS and the second BMS acquisition board 14 .

[0107] It should be noted that the first BMS acquisition board 13 plays a vital role in the energy storage battery system. It can not only collect the key parameters of the battery cells in the lithium titanate battery pack 1 in real time and provide accurate data support for the BMS 3; it can also communicate and coordinate with the BMS 3 to ensure the stable and safe operation of the entire system. At the same time, the power supply output end of the first BMS acquisition board 13 can also provide the necessary power support for the temperature control device 6 to ensure that the temperature control device 6 can work normally when needed.

[0108] Specific usage logic (charging):

[0109] (1) Within the normal temperature range (satisfying normal charging of the iron-lithium battery pack 2), the battery pack can be charged in the following ways:

[0110] A: When connected to an external charging system, the charging is confirmed through communication, the first main positive relay 7 and the first main negative relay 8 are closed, the lithium titanate battery pack 1 is charged, and the DCDC circuit 5 is turned on at the same time. The DCDC circuit 5 charges the iron-lithium battery pack 2 at a constant voltage. When the lithium titanate battery pack 1 is fully charged, the BMS disconnects the first main negative relay 8 and stops charging the lithium titanate battery pack 1. When the iron-lithium battery pack 2 is fully charged, the BMS 3 turns off the DCDC circuit 5 through the CAN signal to stop charging the iron-lithium battery pack 2. At the same time, the BMS 3 turns off the charging system to complete the charging process. The lithium titanate battery pack 1 and the iron-lithium battery pack 2 are controlled independently. The DCDC circuit 5 is controlled to be turned on and off by the BMS 3 to control the on and off of the charging of the iron-lithium battery pack 2.

[0111] B: When no external charging system is connected, when BMS 3 detects that the voltage of the iron-lithium battery pack 2 is too low (the charging threshold at this time can be set by the iron-lithium battery pack 2), BMS 3 closes the first main negative relay 8, opens the DCDC circuit 5, and the lithium titanate battery pack 1 charges the iron-lithium battery pack 2 through the DCDC circuit 5. After fully charged, the DCDC circuit 5 is closed and the first main negative relay 8 is disconnected. The iron-lithium battery pack 2 is charged by the lithium titanate battery pack 1, and the iron-lithium battery pack 2 is supplemented with electricity, so as to avoid the impact of the iron-lithium battery pack 2 on the battery life and improve the charging and discharging efficiency of the entire battery pack.

[0112] (2) In the case of abnormal temperature (not meeting the normal charging requirements of the lithium iron battery pack 2), the battery pack is charged using the following charging methods:

[0113] A: In low temperature conditions, when the external charging system is connected, charging confirmation is performed through communication, the first main positive relay 7 and the first main negative relay 8 are closed, and the lithium titanate battery pack 1 is charged. At this time, the 12 / 24V power supply output by the first BMS 3 acquisition board is used to heat the iron lithium battery pack 2 through the BMS 3. When the iron lithium battery pack 2 reaches the normal charging temperature after being heated by the heating film (powered by the BMS 3), the DCDC circuit 5 is turned on to charge the iron lithium battery pack 2. At the same time, the BMS 3 turns off the heating power switch and stops heating. The above conventional charging is then performed (case A in (1)). When the temperature is too low, the iron lithium battery pack 2 is heated to a certain temperature and then charged. At this time, the lithium titanate battery pack 1 is charged synchronously.

[0114] B: In low temperature conditions, when no external charging system is connected, when BMS 3 detects that the voltage of the lithium iron battery pack 2 is too low (the charging threshold at this time can be set by the lithium iron battery pack 2), BMS 3 closes the first main negative relay 8, and heats the lithium iron battery pack 2 as in the above step (case A in (2)), and then charges. After BMS 3 heats the lithium iron battery pack 2, the lithium titanate battery pack 1 charges the lithium iron battery pack 2.

[0115] C: Under high temperature conditions (not meeting the normal charging requirements of the iron-lithium battery), when the external charging system is connected, the charging is confirmed through communication, the first main positive relay 7 and the first main negative relay 8 are closed, and the lithium titanate battery pack 1 is charged. At this time, the 12 / 24V power supply output by the first BMS acquisition board 13 is supplied to the fan of the iron-lithium battery pack 2 through the BMS 3 for cooling. When the battery pack is cooled by the fan and the temperature reaches the normal charging temperature (which can be set according to the battery performance), the DCDC circuit 5 is turned on to charge the iron-lithium battery pack 2, and the fan continues to cool until the iron-lithium battery pack 2 is fully charged or the temperature reaches the fan shutdown condition (the temperature threshold is set by yourself), and then the fan is turned off. The lithium titanate battery pack 1 is charged, and the iron-lithium battery pack 2 is charged after being cooled synchronously.

[0116] D: In high temperature conditions (not meeting normal charging requirements for the iron-lithium battery), when no external charging system is connected, when BMS 3 detects that the voltage of the iron-lithium battery pack 2 is too low (the charging threshold at this time can be set according to the iron-lithium battery pack 2), BMS 3 closes the fan control switch to cool the iron-lithium battery pack 2 first. When the battery pack temperature reaches the normal charging temperature (which can be set according to the battery performance), the first main negative relay 8 is closed, and the DCDC circuit 5 is turned on to charge the iron-lithium battery pack 2. The fan continues to cool until the iron-lithium battery pack 2 is fully charged or the temperature reaches the fan shutdown condition (the temperature threshold is designed by yourself), and then the fan is turned off. After charging is completed, the first main negative relay 8 is disconnected and the DCDC circuit 5 is turned off. After BMS 3 cools the iron-lithium battery pack 2, the lithium titanate battery pack 1 charges the iron-lithium battery pack 2.

[0117] Specific use logic (discharge):

[0118] (1) Within the normal temperature range (meeting the normal discharge of the lithium iron battery pack 2), the battery pack can be discharged in the following ways. The lithium titanate battery pack 1 and the lithium iron battery pack 2 cannot be discharged at the same time to avoid the voltage difference between the parallel circuits, prevent circulating current, avoid affecting the load power supply, and prevent impact on the battery pack.

[0119] A: When the battery pack is connected to the load and there is no external charging system connected, BMS 3 closes the second main negative relay 9 and the pre-charge relay 402 to pre-charge the iron-lithium battery pack 2, and discharges the iron-lithium battery pack 2 first. When the iron-lithium battery pack 2 is discharged, the load power-off process is completed according to the normal power-off logic, and then the first main negative relay 8 and the third relay 10 are closed to pre-charge the lithium titanate battery pack 1. After the lithium titanate battery pack 1 is powered on, it supplies power to the load until the lithium titanate battery pack 1 is used up and then powered off, stopping the power supply to the load. The purpose of the pre-charge process is to charge the pre-charge capacitor of the motor controller to reduce the spark arc when the high-voltage relay is closed, avoid high-voltage shock from damaging high-voltage components, and improve the safety of the high-voltage system. After the iron-lithium battery pack 2 is discharged, the lithium titanate battery pack 1 is discharged.

[0120] B: When the battery pack is connected to a load and connected to a charging device because the battery pack is low on power, discharge is performed in the following ways:

[0121] a: When the power of the charging device is greater than the load power, the charging system will charge the lithium titanate battery pack 1 and the lithium iron battery pack 2 while meeting the power demand of the device. After the battery pack is fully charged, the BMS 3 stops charging the battery pack and reduces the power of the charging device to ensure the normal operation of the system.

[0122] b: When the power of the charging device is less than the load power, the charging system and the iron-lithium battery pack 2 supply power to the load at the same time. When the iron-lithium battery pack 2 is discharged, the second main negative relay 9 is disconnected and the first main negative relay 8 and the third relay 10 are closed. The lithium titanate battery pack 1 and the charging system supply power to the load at the same time. When the lithium titanate battery pack 1 is discharged, the BMS 3 sends a load stop command and disconnects the load and the second main positive relay 401 to complete the power-off of the load. The charger continues to charge the lithium titanate battery pack 1 and the iron-lithium battery pack 2. The charging logic is allocated according to the above situation.

[0123] (2) In the case of abnormal temperature (not meeting the normal discharge requirements of the lithium iron battery pack 2), the battery pack can be discharged in the following ways:

[0124] A: In low temperature conditions, when the battery pack is connected to a load and not connected to a charging system, BMS 3 closes the first main negative relay 8 and the third relay 10 to pre-charge the lithium titanate battery pack 1, and discharges the lithium titanate battery pack 1 first. At this time, the 12 / 24V power supply output by the first BMS acquisition board 13 heats the iron-lithium battery pack 2 through BMS 3. When the temperature of the iron-lithium battery pack 2 reaches the normal discharge temperature after being heated by the heating film, the lithium titanate battery pack 1 is powered off, and then the iron-lithium battery pack 2 is powered on and discharged. At the same time, BMS 3 turns off the heating power switch and stops heating. When the power of the iron-lithium battery pack 2 is used up, the lithium titanate battery pack 1 continues to be used until the power of the lithium titanate battery pack 1 is used up and the discharge stops (the discharge of the iron-lithium battery pack 2 is given priority because the environmental adaptability of the iron-lithium battery pack 2 is poor);

[0125] B: In low temperature conditions, when the battery pack is connected to a load and a charging device, the following conditions may occur:

[0126] a: When the power of the charging device is greater than the load power, the charging system will charge the lithium titanate battery pack 1 while meeting the power demand of the device. The 12 / 24V power output by the first BMS acquisition board 13 heats the lithium iron battery pack 2 through the BMS 3. When the temperature of the lithium iron battery pack 2 reaches the normal charging temperature after heating, the DCDC circuit 5 is turned on to charge the lithium iron battery pack 2. At the same time, the BMS 3 turns off the heating power switch and stops heating. When the lithium iron battery pack 2 is fully charged, the DCDC circuit 5 is turned off. When the lithium titanate battery pack 1 is fully charged, the BMS 3 reduces the power of the charging device to ensure the normal operation of the system. The lithium iron battery pack 2 is heated and charged, and the lithium titanate battery pack 1 is charged at the same time.

[0127] b: When the power of the charging device is less than the load power, the charging system and the iron-lithium battery pack 2 supply power to the load at the same time. The 12 / 24V power supply output by the first BMS acquisition board 13 heats the iron-lithium battery pack 2 through the BMS 3. When the temperature of the iron-lithium battery pack 2 reaches the normal discharge temperature after heating, the BMS 3 turns off the heating power switch and stops heating (when the temperature is lower than the normal temperature, the heating is turned on again). When the lithium titanate battery pack 1 is discharged, the first main negative relay 8 and the third relay 10 are disconnected, and then the second main negative relay 9 is closed. The iron-lithium battery pack 2 and the charging system supply power to the load at the same time. When the iron-lithium battery pack 2 is discharged, the BMS3 sends a load stop command, disconnects the load and closes the second main positive relay 401. The charger continues to charge the lithium titanate battery pack and 2. The charging logic is carried out according to the above situation.

[0128] C: In high temperature conditions (not meeting the normal discharge of the iron-lithium battery), when the battery pack is connected to the load and not connected to the charging system, the BMS 3 closes the first main negative relay 8 and the third relay 10, pre-charges the lithium titanate battery pack 1, and discharges the lithium titanate battery pack 1 first. The 12 / 24V power supply output by the first BMS acquisition board 13 is supplied to the fan of the iron-lithium battery pack 2 through the BMS 3 for cooling. When the iron-lithium battery pack 2 is cooled by the fan and the temperature reaches the normal discharge temperature (which can be set according to the battery performance), the fan continues to cool, first disconnects the first main negative relay 8 and then closes the second main negative relay 9, and uses the iron-lithium battery pack 2 to discharge. When the iron-lithium battery pack 2 is discharged, the iron-lithium battery pack 2 is powered off and then discharges the lithium titanate battery pack 1. After the lithium titanate battery pack 1 is discharged, it is powered off according to the normal power-off process. The lithium titanate battery pack 1 is discharged first, the iron-lithium battery pack 2 is cooled, and then the iron-lithium battery pack 2 is discharged, and finally the lithium titanate battery pack 1 is discharged.

[0129] D: Under high temperature conditions (not meeting the normal discharge requirements of the lithium iron battery pack 2), when the battery pack is connected to a load and the charging system is connected:

[0130] a: When the power of the charging device is greater than the load power, the charging system will charge the lithium titanate battery pack 1 while meeting the power demand of the device. The 12 / 24V power supply output by the first BMS acquisition board 13 supplies power to the fan of the iron-lithium battery pack 2 through the BMS 3 for cooling. When the iron-lithium battery pack 2 is cooled and the temperature reaches the normal charging temperature (which can be set according to the battery performance), the charging of the iron-lithium battery pack 2 is started. When the lithium titanate battery pack 1 and the iron-lithium battery pack 2 are fully charged, the BMS 3 reduces the power of the charging device and stops charging the lithium titanate battery pack 1 and the iron-lithium battery pack 2 to ensure the normal operation of the system (when the temperature reaches the fan closing condition in the middle, the fan is turned off, and the fan can be turned on and off according to the temperature). The lithium titanate battery pack 1 is charged, and the iron-lithium battery pack 2 is charged at the same time after cooling.

[0131] b: When the power of the charging device is less than the load power, the charging system and the lithium titanate battery pack 1 supply power to the load at the same time. The 12 / 24V power supply output by the first BMS acquisition board 13 supplies power to the fan of the iron-lithium battery pack 2 through the BMS 3 for cooling. When the temperature of the iron-lithium battery pack 2 reaches the normal discharge temperature, the first main negative relay 8 and the third relay 10 are disconnected, and then the second main negative relay 9 is closed. The iron-lithium battery pack 2 and the charging system supply power to the load at the same time. When the iron-lithium battery pack 2 is discharged, the iron-lithium battery pack 2 is powered off and the lithium titanate battery pack 1 is powered on. When the lithium titanate battery pack 1 is discharged, the BMS 3. Send a load stop command, disconnect the load and close the second main positive relay 401. The charger continues to charge the lithium titanate battery pack 1 and the iron-lithium battery pack 2. The charging logic is as above (when the iron-lithium battery pack 2 is fully discharged or the temperature reaches the fan closing condition, the fan is turned off. The fan can be turned on and off according to the temperature). The lithium titanate battery pack 1 is discharged first, and the iron-lithium battery pack 2 is cooled. After the lithium titanate battery pack 1 is fully discharged, the iron-lithium battery pack 2 is discharged.

[0132] Under normal circumstances, when the load needs to work at a high rate, the lithium titanate battery pack 1 can be preferentially controlled to supply power to the load. At the same time, the charging system is started to replenish the power of the lithium titanate battery pack 1 according to the power status of the lithium titanate battery pack 1, so as to jointly meet the power consumption of the load and ensure the normal operation of the battery pack.

[0133] The above control strategies only list some of the possible situations. This battery pack is compatible with more charging and discharging situations and meets more control strategies.

[0134] Although the terms such as lithium titanate battery pack, lithium iron battery pack, and battery management system BMS are used more frequently in this application, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

[0135] The utility model provides an energy storage battery system, which consists of a lithium titanate battery pack, a lithium iron battery pack, a battery management system BMS, a pre-charging circuit, a DCDC circuit, a temperature control device, a first main positive relay, a first main negative relay, a second main negative relay, a third relay, a charging port and a discharging port. By performing specific circuit design, the overall performance of the battery system is improved, including environmental adaptability, stability, safety and service life, etc., which is conducive to promoting the progress and development of battery technology and providing more reliable, efficient and safe energy solutions for electric vehicles, energy storage systems and other fields.

[0136] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. An energy storage battery system, characterized in that: It comprises a lithium titanate battery pack (1), a lithium iron battery pack (2), a battery management system BMS (3), a pre-charging circuit (4), a DCDC circuit (5), a temperature control device (6), a first main positive relay (7), a first main negative relay (8), a second main negative relay (9), a third relay (10), a charging port (11) and a discharging port (12); wherein: The positive electrode of the iron-lithium battery pack (2) is connected to the positive electrode of the charging port (11) through the DCDC circuit (5), and the negative electrode of the iron-lithium battery pack (2) is connected to the negative electrode of the charging port (11), so as to form a first charging circuit; the positive electrode of the iron-lithium battery pack (2) is connected to the positive electrode of the discharge port (12) through the pre-charging circuit (4), and the negative electrode of the iron-lithium battery pack (2) is connected to the negative electrode of the discharge port (12), so as to form a first discharge circuit; The positive electrode and negative electrode of the lithium titanate battery pack (1) are respectively connected to the positive electrode and negative electrode of the charging port (11) to form a second charging circuit; the positive electrode of the lithium titanate battery pack (1) is connected to the positive electrode of the discharge port (12) through the pre-charging circuit (4), and the negative electrode of the lithium titanate battery pack (1) is connected to the negative electrode of the discharge port (12) to form a second discharge circuit; The positive electrode and negative electrode of the lithium titanate battery pack (1) are also respectively connected to the positive electrode and negative electrode of the lithium iron battery pack (2) through the DCDC circuit (5); The temperature control device (6) is located inside the iron-lithium battery pack (2); The first main positive relay (7) is connected in series to the positive electrode of the charging port (11); The first main negative relay (8) is connected in series to the negative electrode of the lithium titanate battery pack (1); The second main negative relay (9) is connected in series to the negative electrode of the iron-lithium battery pack (2); The third relay (10) is connected in series between the positive electrode of the lithium titanate battery pack (1) and the pre-charging circuit (4); The temperature control device (6), the first main positive relay (7), the first main negative relay (8), the second main negative relay (9), the third relay (10), the DCDC circuit (5) and the pre-charging circuit (4) are respectively connected to the BMS (3).

2. The energy storage battery system according to claim 1, characterized in that: The pre-charging circuit (4) comprises a second main positive relay (401), a pre-charging relay (402) and a pre-charging resistor (403); The pre-charging relay (402) is connected in series with the pre-charging resistor (403) and then connected in parallel with the second main positive relay (401); The second main positive relay (401) and the pre-charge relay (402) are respectively connected to the BMS (3).

3. The energy storage battery system according to claim 1, characterized in that: It also includes a first BMS acquisition board (13) and a second BMS acquisition board (14); The first BMS acquisition board (13) is located in the lithium titanate battery pack (1) and is connected to the battery cells in the lithium titanate battery pack (1); The second BMS acquisition board (14) is located in the iron-lithium battery pack (2) and is connected to the battery cells in the iron-lithium battery pack (2); The first BMS acquisition board (13) and the second BMS acquisition board (14) are respectively connected to the BMS (3); The temperature control device (6) is connected to the second BMS acquisition board (14).

4. The energy storage battery system according to claim 3, characterized in that: The temperature control device (6) comprises a heating device (601) and a heat dissipation device (602); The heating device (601) and the heat dissipation device (602) are respectively connected to the second BMS acquisition board (14).

5. The energy storage battery system according to claim 4, characterized in that: The heating device (601) is a heating film.

6. The energy storage battery system according to claim 4, characterized in that: The heat dissipation device (602) is a fan.

7. The energy storage battery system according to claim 4, characterized in that: It also includes a first fuse protection device (15); The first fuse protection device (15) is connected in series to the heating device (601).

8. The energy storage battery system according to claim 1, characterized in that: Also includes a second fuse protection device (16); The negative electrode of the lithium titanate battery pack (1) and the negative electrode of the lithium iron battery pack (2) are respectively connected to a common negative electrode; The second fuse protection device (16) is connected in series to the common negative electrode.

9. The energy storage battery system according to claim 1, characterized in that: Also includes a third insurance protection device (17); The third fuse protection device (17) is connected in series between the negative electrode of the iron-lithium battery pack (2) and the DCDC circuit (5).

10. The energy storage battery system according to claim 3, characterized in that: The collection end of the first BMS collection board (13) is connected to the battery cell in the lithium titanate battery pack (1); The communication terminal of the first BMS acquisition board (13) is connected to the BMS (3); The power supply output end of the first BMS acquisition board (13) is connected to the temperature control device (6) via the BMS (3) and the second BMS acquisition board (14).

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