Power battery system

Abstract

The invention provides a power battery system. The power battery system comprises a plurality of battery branches connected in parallel; the battery management module comprises a first-stage management and control unit, a second-stage management and control unit and a third-stage management and control unit; wherein the three-stage management and control unit is configured to obtain first state information of each single battery; the second-stage management and control unit is connected with the third-stage management and control unit, and is configured to obtain the first state information from the third-stage management and control unit, calculate the second state information of the corresponding battery branch according to the first state information, and determine the fault information of the battery branch; and the first-stage management and control unit is connected with the second-stage management and control unit and is configured to obtain the first state information, the second state information and the fault information from the second-stage management and control unit, and determine whether to cut off the fault branch based on the fault information. The fault branch can be automatically cut off, and the situation that the whole power battery system cannot operate is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a power battery system. Background Art

[0002] As new energy vehicles have less impact on the environment than traditional vehicles, they are widely considered to be one of the main ways to solve problems such as automobile exhaust pollution and oil energy shortages, and are the current development trend of the automobile industry. As the energy source of new energy vehicles, power batteries are an important part of new energy vehicles.

[0003] In order to increase the power and voltage of the power battery, the power battery generally uses multiple single cells connected in series to form a battery branch, and then multiple battery branches are used in parallel, thereby improving the endurance of new energy vehicles. However, when the power battery has the following problems: when a single cell or a battery branch fails, the entire battery system will be out of service as a whole, causing the vehicle to break down directly. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the entire power battery cannot be used when a single battery or a battery branch fails. The present invention provides a power battery system that can automatically cut off the faulty branch to prevent the entire power battery system from being unable to operate.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a power battery system, comprising:

[0006] A plurality of parallel battery branches, each battery branch includes a plurality of single cells and a switch unit, and the plurality of single cells are connected in series to form a battery pack and then connected in series with the switch unit;

[0007] and, a battery management module, including a primary control unit, a secondary control unit, and a tertiary control unit;

[0008] Wherein, a three-level control unit is respectively arranged in each battery pack, and the three-level control unit is configured to obtain first status information of each single battery;

[0009] A secondary control unit is respectively provided in each battery branch, the secondary control unit is connected to the tertiary control unit of the battery branch, and is configured to obtain first status information from the tertiary control unit and calculate second status information of the corresponding battery branch according to the first status information and determine fault information of the battery branch;

[0010] The primary control unit is connected to the secondary control unit, and is configured to obtain first state information, second state information and fault information from the secondary control unit, and determine whether to cut off the fault branch based on the fault information.

[0011] According to another specific embodiment of the present invention, the first status information includes a cell voltage value, a cell temperature value and a balancing circuit state of the single cell.

[0012] According to another specific embodiment of the present invention, the second status information includes a voltage comparison result of a single cell, a temperature comparison result, a total voltage of a battery branch, a current, SOX, information on whether the battery branch is in a charging or discharging state, and a communication state with a third-level control unit, wherein the second-level control unit obtains a voltage comparison result by comparing a single cell voltage value and a single cell temperature value of the single cell with an overvoltage setting threshold and an undervoltage setting threshold, respectively, and obtains a temperature comparison result by comparing a single cell temperature value with a high temperature setting threshold and a low temperature setting threshold, respectively.

[0013] According to another specific embodiment of the present invention, the secondary management and control unit determines the fault information of the corresponding battery branch based on the voltage comparison result, the temperature comparison result and the communication status, and the fault information includes the address of the faulty single cell and the address of the corresponding battery branch, the fault type and the fault level.

[0014] According to another specific embodiment of the present invention, determining whether to cut off the fault branch based on the fault information includes:

[0015] The primary control unit determines whether the corresponding battery branch needs to be disconnected based on the fault level, and sends a branch disconnection instruction to the secondary control unit of the battery branch that needs to be disconnected;

[0016] After the secondary control unit receives the branch disconnection instruction, the secondary control unit controls the switch unit of the battery branch to disconnect.

[0017] According to another specific embodiment of the present invention, the switch unit is a relay.

[0018] According to another specific embodiment of the present invention, the primary control unit is also connected to the vehicle controller;

[0019] When the primary control unit determines that the battery branch needs to be disconnected, it also includes:

[0020] The first-level control unit sends a request to the vehicle controller to reduce the output current of the power battery system. When the output current of the power battery system is reduced to below the allowable load cut-off current, the first-level control unit sends a branch disconnection instruction to the second-level control unit of the battery branch.

[0021] According to another specific embodiment of the present invention, the secondary control unit further calculates the total voltage of the battery branch based on the voltage of each single battery and sends the total voltage to the primary control unit;

[0022] When charging the power battery system, the primary control unit calculates the difference in the total voltage between each battery branch. When the maximum value of the difference in the total voltage between the battery branches is greater than the total voltage difference set threshold:

[0023] The primary control unit sends a branch closing instruction to the secondary control unit of the battery branch with the lowest total voltage. The secondary control unit that receives the branch closing instruction closes the switch unit of the battery branch to charge the battery branch until the difference between the total voltage of the battery branch and the battery branch with the second lowest total voltage is less than the total voltage difference setting threshold. The primary control unit sends a branch closing instruction to the secondary control unit of the battery branch with the second lowest total voltage.

[0024] The above steps are repeated until the total voltage differences between the battery branches are all less than the total voltage difference set threshold.

[0025] According to another specific embodiment of the present invention, it also includes multiple current sensors, which correspond one to one with multiple battery branches. The current sensors are connected in series in the battery branch and connected to the secondary control unit of the battery branch, and are used to collect the current state of the battery branch and send it to the primary control unit. The primary control unit determines whether the battery branch is in a charging state or a discharging state according to the current state of the battery branch.

[0026] According to another specific embodiment of the present invention, it also includes a pre-charging circuit, which is connected to the first-level management and control unit. The pre-charging circuit is arranged between the parallel connection end of the battery branch and the battery output end. The pre-charging circuit includes a main control relay, a pre-charging relay and a pre-charging resistor. After the pre-charging relay is connected in series with the pre-charging resistor, it is connected in parallel with the main control relay.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] By configuring a three-level control unit for each battery pack, configuring a secondary control unit for each battery branch to manage the battery branch, and configuring a primary control unit on the output main road of the power battery, wherein the three-level control unit is used to obtain the first state information of the single battery, and output the first state information of each single battery to the secondary control unit of the battery branch where it is located, the secondary control unit calculates the second state information of the battery branch according to the received first state information and determines the fault information of the battery branch, and outputs the first state information of the single battery, the second state information of the battery branch and the fault information to the primary control unit, the primary control unit monitors the state of each single battery and each battery branch in real time according to the first state information and the second state information, and determines whether it is necessary to cut off the fault branch according to the fault information. The power battery system provided by the present invention can monitor the battery state in real time, and when one of the battery branches fails, the fault branch can be cut off, while other battery branches can continue to supply power, so that the power battery system can continue to work, ensuring that the vehicle can temporarily run or travel to the maintenance place, avoiding the problem that the entire power battery cannot be used due to the failure of one battery branch or the single battery in the battery branch. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic structural diagram of a power battery system provided by an embodiment of the present invention is shown;

[0030] Figure 2 A circuit connection diagram of a power battery system provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0031] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0032] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0033] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0035] In the description of this embodiment, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0036] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic diagram of the structure of a power battery system provided by an embodiment of the present invention. In this embodiment, the power battery system includes:

[0038] A plurality of parallel battery branches, each battery branch includes a plurality of single cells and a switch unit, and the plurality of single cells are connected in series to form a battery pack and then connected in series with the switch unit;

[0039] And, the battery management module includes a primary management and control unit BAU (Battery Array Unit), a secondary management and control unit BCU (Battery Cluster Management Unit) and a tertiary management and control unit BMU (Battery Management Unit);

[0040] Wherein, a three-level control unit is respectively arranged in each battery pack, and the three-level control unit is configured to obtain first status information of each single battery;

[0041] A secondary control unit is respectively provided in each battery branch, the secondary control unit is connected to the tertiary control unit of the battery branch, and is configured to obtain first status information from the tertiary control unit and calculate second status information of the corresponding battery branch according to the first status information and determine fault information of the battery branch;

[0042] The primary control unit BAU is connected to the secondary control unit BCU, and is configured to obtain first status information, second status information and fault information from the secondary control unit BCU, and determine whether to cut off the fault branch based on the fault information.

[0043] This technical solution is adopted by configuring a three-level management and control unit BMU for each battery pack, configuring a secondary management and control unit BCU for each battery branch to manage the battery branch, and configuring a primary management and control unit BAU on the output main road of the power battery, wherein the three-level management and control unit BMU is used to obtain the first status information of the single cell battery, and output the first status information of each single cell battery to the secondary management and control unit BCU of the battery branch where it is located, the secondary management and control unit BCU calculates the second status information of the battery branch according to the received first status information and determines the fault information of the battery branch, and outputs the first status information of the single cell battery, the second status information of the battery branch and the fault information to the primary management and control unit BAU, the primary management and control unit BAU monitors the status of each single cell battery and each battery branch in real time according to the first status information and the second status information, and determines whether the faulty branch needs to be cut off according to the fault information. The power battery system provided by the present invention can monitor the battery status in real time. When a fault occurs in one of the battery branches, the faulty branch can be cut off, while other battery branches can continue to supply power, thereby maintaining the operation of the power battery system and ensuring that the vehicle can be temporarily operated or travel to a maintenance site, avoiding the problem of the entire power battery being unusable due to a fault in a battery branch or a single cell in the battery branch.

[0044] Figure 2 The following is a schematic diagram of the circuit connection of a power battery system provided by an embodiment of the present invention. Figure 1 and Figure 2 As shown, in this embodiment, the power battery system includes three parallel battery branches (battery branch 1, battery branch 2 and battery branch 3), each battery branch includes a battery pack formed by connecting a plurality of single cells in series and a switch unit (K21~K23), and a switch unit is connected in series with a battery pack to form the battery branch.

[0045] Each battery pack is equipped with a three-level management and control unit BMU, which is used to monitor each single battery in the battery pack and obtain the first status information of each single battery. Figure 2 As shown, each battery pack can be configured with more than one three-level management and control unit BMU. The number of the three-level management and control units BMU can be set according to the number of single cells connected in series in the battery pack.

[0046] Each battery branch is configured with a secondary control unit BCU, which is connected to the tertiary control unit BMU of the battery branch through a communication link to obtain the first status information of each single battery in the battery branch, and determine the second status information of the battery branch and the fault information of the battery branch according to the first status information. In this embodiment, the secondary control unit includes 1#BCU, 2#BCU and 3#BCU respectively managing three parallel battery branches. Figure 1 As shown, in this embodiment, three secondary control units BCU can be integrated into one control box.

[0047] The primary control unit BAU is connected to the secondary control unit BCU of each battery branch through a communication link, and is used to monitor the status of each single battery and each battery branch in real time and manage the secondary control unit BCU of each battery branch. The primary control unit BAU obtains the first status information, the second status information and the fault information output by the secondary control unit BCU, and determines whether the battery branch needs to cut off the faulty branch according to the fault information. If it is determined that the faulty branch needs to be cut off, the corresponding battery branch is cut off.

[0048] Therefore, a three-level control architecture is adopted, in which the third-level control unit BMU obtains the first status information of each single battery, and a second-level control unit BCU manages a battery branch, and the first-level control unit BAU is responsible for overall control. This can avoid information confusion caused by too much communication data and improve the effectiveness, reliability and stability of control.

[0049] Optionally, in this embodiment, the communication link is a CAN (Controller Area Network) bus.

[0050] Furthermore, the first status information includes a cell voltage value, a cell temperature value and a balancing circuit state of the single cell.

[0051] Furthermore, the second status information includes the voltage comparison result of the single cell, the temperature comparison result, the total voltage and current of the battery branch, SOX (State Of X, a general term for battery status, including SOH, SOC, SOP and SOE, which respectively represent battery health status, battery remaining power, battery power status and battery energy status), information on whether the battery branch is in a charging or discharging state and a communication status with the third-level control unit BMU, wherein the second-level control unit BCU obtains a voltage comparison result by comparing the single cell voltage value of the single cell with the overvoltage setting threshold and the undervoltage setting threshold, and obtains a temperature comparison result by comparing the single cell temperature value with the high temperature setting threshold and the low temperature setting threshold.

[0052] Thus, the status of each single battery and the status of each battery branch can be obtained in real time.

[0053] Specifically, after obtaining the single cell voltage value and single cell temperature value of each single cell in its battery branch, the secondary control unit BCU compares the set overvoltage setting threshold, undervoltage setting threshold, high temperature setting threshold and low temperature setting threshold, and reports the comparison result to the primary control unit BAU.

[0054] The secondary control unit BCU also calculates the total voltage of the battery branch according to the single cell voltage values ​​of each single cell in the battery branch.

[0055] Optionally, the second status information also includes the highest single cell voltage, the highest temperature, the lowest single cell voltage and the lowest temperature determined by the secondary control unit BCU according to the single cell voltage values ​​and single cell temperature values ​​of each single cell of the battery branch.

[0056] Furthermore, the secondary control unit BCU determines the fault information of the corresponding battery branch based on the voltage comparison result, the temperature comparison result and the communication status. The fault information includes the address of the faulty single cell and the address of the corresponding battery branch, the fault type and the fault level.

[0057] By adopting this technical solution, the fault point and type of fault can be determined.

[0058] Specifically, the secondary control unit BCU determines whether the single cell has an overvoltage, undervoltage, high temperature or low temperature fault based on the comparison results of the single cell voltage value of the single cell with the set overvoltage setting threshold and undervoltage setting threshold, and the comparison results of the single cell temperature value with the set high temperature setting threshold and low temperature setting threshold, and determines whether there is a communication fault based on the communication status with the tertiary control unit BMU. Fault types include voltage fault, temperature fault and communication fault.

[0059] The secondary control unit BCU reports the address of the faulty single cell and the address of the corresponding battery branch, the fault type and the fault level to the primary control unit BAU. Among them, the fault level includes primary fault, secondary fault and severe fault. The secondary control unit BCU determines the fault level according to the voltage comparison result, temperature comparison result and communication status of its battery branch. Specifically, in this embodiment, by setting different levels of overvoltage setting threshold, undervoltage setting threshold, high temperature setting threshold and low temperature setting threshold, the voltage value and temperature value of the acquired single cell are compared with the set thresholds of different levels, so as to determine the fault level. For example, the overvoltage setting threshold includes three different levels, namely, the first level overvoltage setting threshold, the second level overvoltage setting threshold and the severe overvoltage setting threshold (for example, the first level overvoltage setting threshold is 3.4V, the second level overvoltage setting threshold is 3.5V, and the severe overvoltage setting threshold is 3.6V). When the cell voltage value of the single cell obtained by the battery branch exceeds 3.6V, the fault level of the battery branch is determined to be a severe fault; when the cell voltage value of the single cell obtained by the battery branch exceeds 3.5V but does not exceed 3.6V, the fault level of the battery branch is determined to be a second level fault; when the cell voltage value of the single cell obtained by the battery branch exceeds 3.4V but does not exceed 3.5V, the fault level of the battery branch is determined to be a first level fault. In addition, if the fault type is a communication fault, the fault level is determined to be a severe fault.

[0060] Further, determining whether to cut off the fault branch based on the fault information includes:

[0061] The primary control unit BAU determines whether the corresponding battery branch needs to be disconnected based on the fault level, and the primary control unit BAU sends a branch disconnection instruction to the secondary control unit BCU of the battery branch that needs to be disconnected;

[0062] After the secondary control unit BCU receives the branch disconnect instruction, the secondary control unit BCU controls the switch unit of the battery branch to disconnect.

[0063] Specifically, after the secondary control unit BCU reports the fault information to the primary control unit BAU, the primary control unit BAU determines whether the battery branch needs to be disconnected based on the fault level reported by the secondary control unit BCU, and when it is determined that the battery branch needs to be disconnected, it sends a branch disconnection instruction to the secondary control unit BCU of the battery branch that needs to be disconnected.

[0064] In this embodiment, if the fault level of the secondary control unit BCU received by the primary control unit BAU is a serious fault, the primary control unit BAU determines that the corresponding battery branch has a fault and needs to be disconnected. At this time, the primary control unit BAU sends a branch disconnection instruction to the secondary control unit BCU of the battery branch determined to be a serious fault. After receiving the branch disconnection instruction, the secondary control unit BCU controls the switch unit of the battery branch to disconnect, thereby disconnecting the faulty branch.

[0065] If the fault level of the secondary control unit BCU received by the primary control unit BAU is a primary fault or a secondary fault, it is considered that the battery system can continue to operate in the current state.

[0066] Optionally, in this embodiment, the switch unit is a relay.

[0067] Furthermore, the primary control unit BAU is also connected to the vehicle control unit VCU (Vehicle Control Unit);

[0068] When the primary control unit BAU determines that the battery branch needs to be disconnected, it also includes:

[0069] The first-level control unit BAU sends a request to the vehicle controller VCU to reduce the output current of the power battery system. When the output current of the power battery system is reduced to below the allowable load cut-off current, the first-level control unit BAU sends a branch disconnection instruction to the second-level control unit BCU of the battery branch.

[0070] Specifically, the first-level management and control unit BAU is electrically connected to the vehicle controller VCU through a communication link to exchange information with the vehicle controller VCU.

[0071] When the primary control unit BAU determines that a battery branch needs to be disconnected, if the secondary control unit BCU directly disconnects the relay controlling the battery branch after receiving the branch disconnection instruction, relay adhesion is likely to occur, thereby causing relay failure. Therefore, in this embodiment, when the primary control unit BAU determines that a battery branch needs to be disconnected, the primary control unit BAU exchanges information with the vehicle controller VCU, and the vehicle controller VCU reduces the output current of the entire power battery to below the allowable load cut-off current of the relay. The primary control unit BAU monitors the output current in real time. When the output current of the entire power battery is reduced to below the allowable load cut-off current, the primary control unit BAU sends a branch disconnection instruction to the secondary control unit BCU of the faulty branch, thereby completing the disconnection of the faulty branch, and the power battery is in a disconnected state.

[0072] After disconnecting the faulty circuit, the first-level management and control unit BAU sends the current branch status to the vehicle controller VCU. The vehicle controller VCU restores the output current of the entire power battery to the total current that can be output by the remaining battery branches to ensure the continuous operation of the vehicle, avoid vehicle breakdown, and save costs caused by the fault.

[0073] Furthermore, the secondary control unit BCU also calculates the total voltage of the battery branch based on the voltage of each single battery and sends the total voltage to the primary control unit BAU;

[0074] When charging the power battery system, the primary control unit BAU calculates the difference in the total voltage between each battery branch respectively. When the maximum value of the difference in the total voltage between the battery branches is greater than the set total voltage difference threshold:

[0075] The primary control unit BAU sends a branch closing instruction to the secondary control unit BCU of the battery branch with the lowest total voltage. The secondary control unit BCU that receives the branch closing instruction closes the switch unit of the battery branch, and charges the battery branch through an external DC charging device until the difference in total voltage between the battery branch and the battery branch with the second lowest total voltage is less than the total voltage difference set threshold. The primary control unit BAU sends a branch closing instruction to the secondary control unit BCU of the battery branch with the second lowest total voltage.

[0076] The above steps are repeated until the total voltage differences between the battery branches are all less than the total voltage difference set threshold.

[0077] Specifically, in this embodiment, the power battery system is connected to an external charging device through a power cable to charge it. Optionally, the external charging device is a DC charging device. While sending the closing branch instruction, the primary control unit BAU also sends a charging permission instruction to the vehicle controller VCU. After receiving the charging permission instruction, the vehicle controller VCU controls the external charging device to charge the battery. With this technical solution, the input voltage and current can be dynamically adjusted and controlled in real time through the external DC device charging method and through the communication link connection between the primary control unit BAU and the vehicle controller VCU or the DC charging device. This method has high charging efficiency and can effectively avoid thermal runaway failures caused by uncontrollable current.

[0078] In this embodiment, if a faulty branch occurs, after the faulty branch is repaired, when charging the power battery through an external DC charging device, the primary control unit BAU sorts each battery branch according to the total voltage of each battery branch or the remaining battery capacity (SOC, State of Charge) sent by the secondary control unit BCU, and determines the difference in the total voltage between the battery branches according to the total voltage of each battery branch. If the difference in the total voltage is within the range of the total voltage difference setting threshold, each battery branch is allowed to be charged in parallel, that is, the primary control unit BAU sends a closing instruction to the secondary control unit BCU of each battery branch, and the secondary control unit BCU closes the relay of the corresponding branch. If the difference in the total voltage is greater than the total voltage difference setting threshold, the battery branch with the lowest total voltage is closed first, and the battery branch with the lowest total voltage is charged first; when the voltage of the battery branch with the lowest total voltage reaches a total voltage difference less than the total voltage difference setting threshold, the battery branch with the second lowest total voltage is closed, and the two branches are charged together. The above steps are repeated until the total voltage differences between the battery branches are all less than the total voltage difference set threshold, thereby completing the automatic voltage equalization control of the battery branches.

[0079] By adopting this technical solution, after the faulty branch is repaired and restored to normal, the uncontrollable current of the voltage equalization maintenance can be reduced, the voltage difference between the battery branches can be reduced, and intelligent voltage equalization maintenance and parallel operation can be realized.

[0080] Furthermore, it also includes multiple current sensors, which correspond one to one with multiple battery branches. The current sensors are connected in series in the battery branch and are connected to the secondary control unit BCU of the battery branch. They are used to collect the current state of the battery branch and send it to the primary control unit BAU. The primary control unit determines whether the battery branch is in a charging state or a discharging state according to the current state of the battery branch.

[0081] Specifically, Figure 2 As shown, in this embodiment, the current sensor includes current sensor 1, current sensor 2 and current sensor 3 connected in series in three battery branches. By connecting the current sensors in series on each battery branch, the current sensor is connected to the secondary control unit BCU of the corresponding battery branch, so that the detected current of the battery branch, including the charging current and the discharging current, is output to the secondary control unit BCU. The secondary control unit BCU can determine whether the battery branch is in a charging state or a discharging state according to the current size of the received battery branch, and calculate the remaining battery power in real time, so as to obtain the power state of the battery branch in real time. In addition, the secondary control unit BCU can also determine whether overcurrent occurs during charging and discharging according to the current size, and perform circulating current judgment.

[0082] The secondary control unit BCU outputs the current and remaining power of the corresponding battery branch to the primary control unit BAU. Based on the above information, the primary control unit BAU accumulates the current of each battery branch in real time to obtain the total current of the entire power battery, and calculates the total remaining power based on the total current, so that the power status of the entire power battery can be obtained in real time.

[0083] Furthermore, if Figure 2 As shown, the power battery system according to an embodiment of the present invention also includes a pre-charging circuit, which is connected to the first-level management and control unit BAU. The pre-charging circuit is arranged between the parallel connection end of the battery branch and the battery output end. The pre-charging circuit includes a main control relay K11, a pre-charging relay K12 and a pre-charging resistor R1. After the pre-charging relay K12 is connected in series with the pre-charging resistor R1, it is connected in parallel with the main control relay K11.

[0084] According to the power battery system provided by the present invention, when a single cell or battery branch is found to be faulty, the faulty branch can be disconnected without affecting the normal operation of other battery branches, thereby ensuring the temporary operation of the entire power battery system and avoiding the problem of the entire power battery being down. In addition, when charging the power battery system, intelligent voltage balancing and parallel operation can be achieved.

[0085] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A power battery system, characterized in that: include: A plurality of parallel battery branches, each battery branch comprising a plurality of single cells and a switch unit, wherein the plurality of single cells are connected in series to form a battery pack and then connected in series with the switch unit; and, a battery management module, including a primary control unit, a secondary control unit, and a tertiary control unit; Wherein, the three-level control unit is respectively arranged in each of the battery packs, and the three-level control unit is configured to obtain the first status information of each of the single cells; The secondary control unit is respectively arranged in each of the battery branches, and the secondary control unit is connected to the tertiary control unit of the battery branch, and is configured to obtain the first state information from the tertiary control unit and calculate the second state information of the corresponding battery branch according to the first state information and determine the fault information of the battery branch; The primary control unit is connected to the secondary control unit, and is configured to obtain the first state information, the second state information, and the fault information from the secondary control unit, and determine whether to cut off the fault branch based on the fault information.

2. The power battery system according to claim 1, characterized in that: The first status information includes a cell voltage value, a cell temperature value, and a balancing circuit state of the cell.

3. The power battery system according to claim 2, characterized in that: The second status information includes the voltage comparison result of the single cell, the temperature comparison result, the total voltage, current, SOX of the battery branch, the charging or discharging state of the battery branch and the communication status with the three-level control unit, wherein the secondary control unit obtains the voltage comparison result by comparing the single cell voltage value of the single cell with the overvoltage setting threshold and the undervoltage setting threshold respectively, and obtains the temperature comparison result by comparing the single cell temperature value with the high temperature setting threshold and the low temperature setting threshold respectively.

4. The power battery system according to claim 3, characterized in that: The secondary control unit determines the fault information of the corresponding battery branch based on the voltage comparison result, the temperature comparison result and the communication status, and the fault information includes the address of the faulty single battery and the address of the corresponding battery branch, the fault type and the fault level.

5. The power battery system according to claim 4, characterized in that: The determining whether to cut off the fault branch based on the fault information includes: The primary control unit determines whether the corresponding battery branch needs to be disconnected based on the fault level, and sends a branch disconnection instruction to the secondary control unit of the battery branch that needs to be disconnected; After the secondary control unit receives the branch circuit disconnection instruction, the secondary control unit controls the switch unit of the battery branch circuit to disconnect.

6. The power battery system according to claim 5, characterized in that: The switch unit is a relay.

7. The power battery system according to claim 6, characterized in that: The primary control unit is also connected to the vehicle controller; When the primary control unit determines that the battery branch needs to be disconnected, the method further includes: The first-level control unit sends a request to the vehicle controller to reduce the output current of the power battery system. When the output current of the power battery system is reduced to below the allowable load cut-off current, the first-level control unit sends the branch disconnection instruction to the second-level control unit of the battery branch.

8. The power battery system according to claim 7, characterized in that: The secondary control unit further calculates the total voltage of the battery branch based on the voltage of each of the single cells and sends the total voltage to the primary control unit; When the power battery system is charged, the primary control unit calculates the difference of the total voltage between each of the battery branches respectively. When the maximum value of the difference of the total voltage between the battery branches is greater than the total voltage difference setting threshold: The primary control unit sends a branch closing instruction to the secondary control unit of the battery branch with the lowest total voltage, and the secondary control unit that receives the branch closing instruction closes the switch unit of the battery branch to charge the battery branch until the difference in total voltage between the battery branch and the battery branch with the second lowest total voltage is less than the total voltage difference setting threshold, and the primary control unit sends a branch closing instruction to the secondary control unit of the battery branch with the second lowest total voltage; The above steps are repeated until the total voltage differences between the battery branches are all smaller than the total voltage difference setting threshold.

9. The power battery system according to claim 3 or 8, characterized in that: It also includes multiple current sensors, which correspond one to one with the multiple battery branches. The current sensors are connected in series in the battery branch and connected to the secondary control unit of the battery branch, and are used to collect the current state of the battery branch and send it to the primary control unit. The primary control unit determines whether the battery branch is in a charging state or a discharging state according to the current state of the battery branch.

10. The power battery system according to claim 9, characterized in that: It also includes a pre-charging circuit, which is connected to the first-level control unit. The pre-charging circuit is arranged between the parallel connection end of the battery branch and the battery output end. The pre-charging circuit includes a main control relay, a pre-charging relay and a pre-charging resistor. After the pre-charging relay is connected in series with the pre-charging resistor, it is connected in parallel with the main control relay.

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