Battery system, battery module and battery equalization method

Abstract

The invention discloses a battery system, a battery module and a battery equalization method, and the battery system comprises a DCDC module, a battery pack in the battery module, a control module and a voltage detection module. The input end of the DCDC module is connected with an external power supply, and the output end of the DCDC module is connected with the battery pack; the voltage detection module is connected with the control module and is used for detecting a voltage value of an external power supply and outputting the voltage value to the control module; the control module is respectively connected with the battery module and the battery pack and is used for acquiring voltage values of the battery module and the battery pack; the control module is further used for controlling the DCDC module to work to charge the battery pack when the voltage value of the external power supply is larger than a first set voltage value, the voltage value of the battery module is larger than a second set voltage value, and the voltage difference value of the battery module and the battery pack is larger than a third set voltage value. Therefore, the voltage difference between the battery pack of the battery module is reduced.

Description

Technical Field

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

[0002] The single cells in the battery pack will have performance differences during the charge and discharge process due to factors such as manufacturing process and use environment. If balancing is not performed, the single cells with poor performance may be overcharged or over-discharged, which will accelerate their aging and shorten the life of the entire battery pack.

[0003] The high-voltage system generally installs the battery module first. There must be inconsistencies in the voltages between the battery packs connected in series and parallel in the battery module. The existing technology can only solve the inconsistency in the voltage of the single cells in a single battery pack, but cannot solve the inconsistency in the voltage between battery packs. Summary of the invention

[0004] The main object of the present invention is to provide a battery system, aiming to reduce the voltage difference between battery packs in a battery module.

[0005] To achieve the above object, the present invention provides a battery system, which includes:

[0006] DCDC module, a battery pack in the battery module, a control module and a voltage detection module;

[0007] The input end of the DCDC module is connected to the external power supply, and the output end is connected to the battery pack; the voltage detection module is connected to the control module, and is used to detect the voltage value of the external power supply and output it to the control module;

[0008] The control module is connected to the battery module and the battery pack respectively, and is used to obtain the voltage values ​​of the battery module and the battery pack;

[0009] The control module is also used to control the DCDC module to operate and charge the battery pack when the external power supply voltage value is greater than the first set voltage value, the battery module voltage is greater than the second set voltage value, and the voltage difference between the battery module and the battery pack is greater than the third set voltage value, so as to reduce the voltage difference between the battery module and the battery pack.

[0010] Optionally, the battery system further includes:

[0011] A first switch device is provided between the DCDC module and the circuit of the battery pack, and is used to control the on / off of the circuit between the DCDC module and the battery pack; the voltage detection module is also connected to the output end of the DCDC module, and is used to detect the voltage output by the DCDC module, and output it to the control module;

[0012] The control module is connected to the controlled end of the first switch device, and is used to control the first switch device to be turned on when the output voltage of the DCDC module is within a first set voltage range.

[0013] Optionally, the DCDC module includes: a second switch device and a DCDC circuit;

[0014] A second switch device is provided in the circuit between the external power supply and the DCDC circuit, and is used to control the on / off of the circuit between the external power supply and the DCDC circuit;

[0015] The control module is connected to the controlled end of the second switch device, and is used for controlling the second switch device to be turned on so that the DCDC circuit chops the voltage output by the external power supply and then outputs it.

[0016] Optionally, the DCDC module further includes: a constant current circuit;

[0017] The input end of the constant current circuit is connected to the output end of the DCDC circuit, and the output end is connected to the first switching device;

[0018] The constant current circuit is used to transform the current output by the DCDC circuit and to output a constant set current value to charge the battery pack.

[0019] Optionally, the battery system further comprises: an anti-reverse diode;

[0020] The anti-reverse diode is arranged in a circuit between the first switching device and the battery pack, wherein an anode of the anti-reverse diode is connected to the first switching device, and a cathode of the anti-reverse diode is connected to the battery pack.

[0021] Optionally, the control module is a battery management system in the battery pack.

[0022] Optionally, the battery pack further includes:

[0023] A plurality of battery cells are arranged in series; a resistor and a switch device are arranged in parallel at both ends of each battery cell, and the resistor and the switch device are arranged in series;

[0024] The battery management system is connected to the controlled ends of all switching devices in the battery pack; the battery management system is used to detect the voltage value of each battery cell, and when the voltage difference between a single battery cell voltage and the battery pack voltage is greater than a set voltage difference value, control the switching device corresponding to the battery cell to turn on, so that the resistor consumes the electric energy of the battery cell, thereby reducing the voltage of the battery cell.

[0025] The present invention also proposes a battery module, which includes a plurality of the battery systems described above; the control modules in the battery system are interconnected and used to output the voltage value of the battery pack in which they are located; the control module is also used to receive the voltage values ​​of other battery packs and determine the voltage value of the battery module based on the voltage values ​​of all battery packs.

[0026] The present invention further provides a battery balancing method, which is applied to the battery system according to any one of claims 1 to 7, and comprises:

[0027] Get the voltage values ​​of external power supply, battery pack and battery module;

[0028] Subtract the voltage value of the battery module from the voltage value of the battery pack to obtain the voltage difference;

[0029] If the external power supply voltage value is greater than the first set voltage value, the battery module voltage value reaches the second set voltage value, and the voltage difference value is greater than the third set voltage value, the DCDC module is controlled to charge the battery pack.

[0030] Optionally, the battery pack further includes:

[0031] A plurality of battery cells are arranged in series; a resistor and a switch device are arranged in parallel at both ends of each battery cell, and the resistor and the switch device are arranged in series;

[0032] The battery balancing method further includes:

[0033] Detect the voltage values ​​of multiple cells in the battery pack;

[0034] If the difference between the cell voltage and the battery pack voltage is greater than the set voltage difference value, the corresponding switch device is controlled to be turned on so that the resistor consumes the electric energy of the cell.

[0035] The present invention discloses a battery system, a battery module and a battery equalization method, wherein the battery system comprises: a DCDC module, a battery pack in a battery module, a control module and a voltage detection module; the input end of the DCDC module is connected to an external power supply, and the output end is connected to the battery pack; the voltage detection module is connected to the control module, and is used to detect the voltage value of the external power supply and output it to the control module; the control module is respectively connected to the battery module and the battery pack, and is used to obtain the voltage values ​​of the battery module and the battery pack; the control module is also used to control the DCDC module to work and charge the battery pack when the voltage value of the external power supply is greater than a first set voltage value, the battery module voltage is greater than a second set voltage value, and the voltage difference between the battery module and the battery pack is greater than a third set voltage value, so as to reduce the voltage difference between the battery module and the battery pack. The present invention charges the battery pack by obtaining the voltage of the external power supply, the battery module voltage and the voltage value of the battery pack, and when the voltage difference between the battery module and the battery pack is greater than the third set voltage value, so as to reduce the voltage difference between the battery module and the battery pack. In order to ensure normal charging, it is also necessary to ensure that the voltage of the external power supply and the battery module meet the voltage requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention 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 present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0037] Figure 1 It is a structural schematic diagram of an embodiment of a battery system of the present invention;

[0038] Figure 2 It is a structural schematic diagram of a first embodiment of a battery system of the present invention;

[0039] Figure 3 It is a structural schematic diagram of a second embodiment of a battery system of the present invention;

[0040] Figure 4 It is a first structural schematic diagram of a third embodiment of a battery system of the present invention;

[0041] Figure 5 It is a second structural schematic diagram of the third embodiment of the battery system of the present invention.

[0042] Description of Figure Numbers:

[0043] Label name Label name 10 Voltage detection module 310 The second switching device 20 Control Module 320 DCDC circuit 30 DCDC module 330 Constant current circuit 40 Battery Pack 50 The first switching device

[0044] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0049] The battery module is composed of multiple battery packs 40, each of which includes multiple battery cells. Due to factors such as the manufacturing process and the use environment, the performance of the single battery cells varies during the charge and discharge process. Specifically, after the battery module is charged and discharged, the voltages of the multiple battery cells in the battery pack 40 are inconsistent, and the resulting voltages between the battery packs 40 are inconsistent. A small voltage difference may not have a significant impact on the use of the battery module, but if the voltage difference between the battery packs 40 is too large, it will cause the following problems:

[0050] 1. Affect the overall performance of the battery module, such as capacity reduction, unstable output power, etc.

[0051] 2. It may cause overcharging or over-discharging of part of the battery pack 40, accelerate battery aging, and shorten the battery life.

[0052] 3. Increase safety risks, such as thermal runaway, fire, etc.

[0053] Based on the above problems, the present invention proposes a battery system, referring to Figure 1 , the battery system comprises:

[0054] A DCDC module 30, a battery pack 40 in a battery module, a control module 20 and a voltage detection module 10;

[0055] The input end of the DCDC module 30 is connected to the external power supply, and the output end is connected to the battery pack 40; the voltage detection module 10 is connected to the control module 20, and is used to detect the voltage value of the external power supply and output it to the control module 20;

[0056] The control module 20 is connected to the battery module and the battery pack 40 respectively, and is used to obtain the voltage values ​​of the battery module and the battery pack 40;

[0057] The control module 20 is also used to control the DCDC module 30 to operate and charge the battery pack 40 when the external power supply voltage value is greater than the first set voltage value, the battery module voltage is greater than the second set voltage value, and the voltage difference between the battery module and the battery pack 40 is greater than the third set voltage value, so as to reduce the voltage difference between the battery module and the battery pack 40.

[0058] It should be noted that the battery module includes a plurality of battery packs 40, and the battery system of this solution includes a battery pack 40 in the battery module. The control module 20 is connected to the battery module and the battery pack 40 respectively to obtain the voltage values ​​of the battery module and the battery pack 40; it is easy to understand that the voltage value of the battery pack 40 and the voltage value of the battery module can be obtained by detecting the output voltage of the battery pack 40 and the output voltage value of the battery module respectively. Alternatively, the battery module and the battery pack 40 have a battery management system respectively, and the voltage value of the battery module and the voltage value of the battery pack 40 can be obtained by the battery management system in the battery module and the battery pack 40 respectively. Alternatively, by obtaining the voltage values ​​of all battery packs 40 in the battery module, the average value or mode of the voltage values ​​of all battery packs 40 is used as the voltage value of the battery module. It should be explained that the voltage of the battery module is determined by the voltage values ​​of all battery packs 40 in the battery module, and the consistency of the battery pack 40 with other battery packs 40 in the battery module can be judged by the difference between the voltage of the battery pack 40 and the voltage of the battery module.

[0059] The battery pack 40 is connected to the DCDC module 30; the DCDC module 30 is used to convert the voltage of the external power supply to charge the battery pack 40. This solution detects the voltage value of the battery pack 40 in the battery system and the voltage value of the battery module; compares the voltage value of the battery pack 40 with the voltage value of the battery module, and charges the battery pack 40 through the DCDC module 30 when the voltage of the battery pack 40 is less than the voltage of the battery module and the voltage difference between the battery module and the battery pack 40 is large. This solution charges the battery pack 40 in the battery module through the DCDC module 30, increases the voltage of the battery pack 40, and thus reduces the voltage difference between the battery modules and the battery packs 40.

[0060] In addition, if the voltage of the battery module is too low, it may mean that the battery has been over-discharged. At this time, voltage balancing may not achieve the expected effect and may even further damage the battery performance. Generally, when the total voltage of the battery module is lower than a certain threshold, it may be necessary to perform charging and other operations first to increase the voltage of the battery module to an appropriate range before balancing. Therefore, before performing voltage balancing on the battery pack 40, the voltage value of the battery module needs to be considered.

[0061] In addition, considering the working conditions of the DCDC module 30, the voltage at the input end of the DCDC module 30 should be neither too large nor too small. Specifically, if the input voltage amplitude is too high, the electronic components inside the DCDC module, such as power switch tubes, capacitors, inductors, etc., may be damaged. This may lead to safety issues such as module failure, overheating, and even fire. If the input voltage is too low, the DCDC module may not start normally or work stably. Because the circuit inside the module requires a certain voltage to establish a suitable working state, a too low input voltage may not meet its startup conditions or seriously affect the output performance of the module, such as unstable output voltage, insufficient output power, etc.

[0062] The voltage detection module 10 detects the voltage value of the external power supply and outputs it to the control module 20. The control module 20 obtains the voltage values ​​of the battery module and the battery pack 40. When the voltage value of the external power supply is greater than the first set voltage value, the battery module voltage is greater than the second set voltage value, and the voltage difference between the battery module and the battery pack 40 is greater than the third set voltage value, the control module 20 controls the DCDC module 30 to work and charge the battery pack 40.

[0063] The first set voltage value, the second set voltage value and the third set voltage value can be determined by research and development personnel respectively.

[0064] The control module 20 may include a controller such as MCU, FPGA, SOC or IC. The voltage detection module 10 may include a voltage sensor and an analog-to-digital converter.

[0065] The present invention discloses a battery system, which includes: a DCDC module 30, a battery pack 40 in a battery module, a control module 20 and a voltage detection module 10; the input end of the DCDC module 30 is connected to an external power supply, and the output end is connected to the battery pack 40; the voltage detection module 10 is connected to the control module 20, and is used to detect the voltage value of the external power supply and output it to the control module 20; the control module 20 is respectively connected to the battery module and the battery pack 40, and is used to obtain the voltage values ​​of the battery module and the battery pack 40; the control module 20 is also used to control the DCDC module 30 to work and charge the battery pack 40 when the voltage value of the external power supply is greater than a first set voltage value, the battery module voltage is greater than a second set voltage value, and the voltage difference between the battery module and the battery pack 40 is greater than a third set voltage value, so as to reduce the voltage difference between the battery module and the battery pack 40. The present invention obtains the voltage of the external power supply, the voltage of the battery module and the voltage of the battery pack 40, and charges the battery pack 40 when the voltage difference between the battery module and the battery pack 40 is greater than the third set voltage value, so as to reduce the voltage difference between the battery module and the battery pack 40. In order to ensure normal charging, it is also necessary to ensure that the voltage of the external power supply and the battery module meets the voltage requirements.

[0066] When the battery is charged, the voltage output by the DCDC module 30 cannot exceed the maximum allowable charging voltage of the battery, and the voltage output by the DCDC module 30 needs to be greater than the battery voltage.

[0067] Based on the above reasons, the first embodiment of the present invention is proposed. Figure 2 In this embodiment, the battery system further includes:

[0068] A first switch device 50 is provided between the circuit of the DCDC module 30 and the battery pack 40, and is used to control the on / off of the circuit between the DCDC module 30 and the battery pack 40; the voltage detection module 10 is also connected to the output end of the DCDC module 30, and is used to detect the voltage output by the DCDC module 30, and output it to the control module 20;

[0069] The control module 20 is connected to the controlled end of the first switch device 50 and is used to control the first switch device 50 to be turned on when the output voltage of the DCDC module 30 is within a first set voltage range.

[0070] It should be noted that, in this solution, the DCDC module 30 may be a DCDC module 30 with adjustable output voltage, or a DCDC module 30 with non-adjustable output voltage. If the output voltage of the DCDC module 30 is adjustable, the voltage value output by the DCDC module 30 may be adjusted so that the output voltage is within the first set voltage range. If the output voltage of the DCDC module 30 is non-adjustable, that is, the gain of the DCDC module 30 with respect to voltage is a fixed value; the magnitude of the external power supply voltage directly affects the output voltage value of the DCDC module 30. In order to prevent the DCDC module 30 from outputting a charging voltage that does not meet the requirements to the battery pack 40, in this embodiment, a first switch device 50 is provided in the circuit between the DCDC module 30 and the battery pack 40, and the controlled end of the first switch device 50 is connected to the control module 20. The control module 20 is used to control the first switch device 50 to be turned on when the output voltage of the DCDC module 30 is within the first set voltage range, otherwise, the first switch device 50 is controlled to turn off the path between the DCDC module 30 and the battery pack 40.

[0071] It is easy to understand that the first set voltage range is less than the maximum allowable charging voltage of the battery. The first set voltage range is specifically determined by R&D personnel.

[0072] The first switch device 50 can be a fully controlled device such as a triode, a MOS tube, a relay or an IGBT tube.

[0073] The DCDC module 30 includes: a second switch device 310 and a DCDC circuit 320;

[0074] A second switch device 310 is provided in a circuit between an external power source and the DCDC circuit 320, and is used to control the on / off of the circuit between the external power source and the DCDC circuit 320;

[0075] The control module 20 is connected to the controlled end of the second switch device 310 and is used to control the second switch device 310 to be turned on so that the DCDC circuit 320 chops the voltage output by the external power supply and then outputs it.

[0076] In order to ensure the safety of the circuit, a second switch device 310 is provided between the external power supply and the DCDC circuit 320. In a natural state, the second switch device 310 is in an off state, disconnecting the connection between the external power supply and the DCDC circuit 320. After confirming that the voltage value of the external power supply is greater than the first set voltage value, the voltage of the battery module is greater than the second set voltage value, and the voltage difference between the battery module and the battery pack 40 is greater than the third set voltage value, the control module 20 controls the second switch device 310 to turn on; the DCDC circuit 320 chops the voltage output by the external power supply and outputs it. The voltage detection module 10 detects the voltage output by the DCDC circuit 320 and outputs it to the control module 20; the control module 20 controls the first switch device 50 to turn on when the output voltage value of the DCDC circuit 320 is within the first set voltage range. The second switch device 310 can be a fully controlled device such as a triode, a MOS tube, a relay or an IGBT tube.

[0077] In the second embodiment of the present invention, referring to Figure 3 , the DCDC module 30 further includes: a constant current circuit 330;

[0078] The input end of the constant current circuit 330 is connected to the output end of the DCDC circuit 320, and the output end is connected to the first switch device 50;

[0079] The constant current circuit 330 is used to convert the current output by the DCDC circuit 320 and output a constant set current value to charge the battery pack 40 .

[0080] It is easy to understand that constant current charging can avoid battery overcharging to a certain extent. In the early stage of charging, the battery voltage is low, and constant current charging can provide energy to the battery with a stable current without causing a sharp increase in charging current due to voltage changes. When the battery is close to full, its voltage gradually increases. If an inappropriate charging method is used, the charging current may continue to increase, thereby causing the risk of overcharging. Constant current charging can effectively control the charging process by coordinating with subsequent charging stages (such as constant voltage charging) to prevent overcharging from damaging the battery.

[0081] In addition, different types and specifications of batteries may require different charging strategies during the charging process. Constant current charging is suitable for a variety of battery types and is suitable for charging a variety of batteries. It has strong versatility. The current size of constant current charging is relatively easy to control and adjust, and can be reasonably set according to factors such as battery capacity and charging time requirements.

[0082] The set current value is determined by research and development personnel.

[0083] The battery system further comprises: an anti-reverse diode;

[0084] The anti-reverse diode is arranged in a circuit between the first switch device 50 and the battery pack 40 , wherein an anode of the anti-reverse diode is connected to the first switch device 50 , and a cathode of the anti-reverse diode is connected to the battery pack 40 .

[0085] The anti-reverse diode can prevent the battery pack 40 from outputting current to the DCDC module 30 in reverse when the output voltage of the DCDC module 30 is lower than the voltage of the battery pack 40 .

[0086] It should be noted that the battery module includes a plurality of battery packs 40, and the battery pack 40 includes a battery management system; a DCDC module 30, a battery pack 40, a voltage detection module 10 and a control module 20 with logic operation capability constitute the battery system. It is easy to understand that the control module 20 can be integrated into the battery pack 40, and in particular, the battery management system in the battery pack 40 also has logic operation capability, so that the battery management system can be used as the control module 20 of the battery system.

[0087] In one example, the control module 20 is a battery management system in the battery pack 40. In this example, the battery management system in the battery pack 40 can obtain the voltage information of the battery pack 40 and the voltage information of other battery packs 40 in the same battery module, thereby obtaining the voltage difference between the battery module and the battery pack 40.

[0088] In order to achieve voltage balancing of the battery module, in addition to voltage balancing between battery packs 40, voltage balancing of the cells in the same battery pack 40 is also required. Based on this, a third embodiment of the present invention is proposed, referring to Figure 4 and Figure 5 , the battery pack 40 further includes:

[0089] A plurality of battery cells are arranged in series; a resistor and a switch device are arranged in parallel at both ends of each battery cell, and the resistor and the switch device are arranged in series;

[0090] The battery management system is connected to the controlled ends of all switching devices in the battery pack 40; the battery management system is used to detect the voltage value of each battery cell, and when the voltage difference between the voltage of a single battery cell and the voltage of the battery pack 40 is greater than a set voltage difference value, the switching device corresponding to the battery cell is controlled to be turned on, so that the resistor consumes the electric energy of the battery cell, thereby reducing the voltage of the battery cell.

[0091] It should be noted that a resistor and a switch device are arranged in parallel at both ends of the battery cell, wherein the resistor and the switch device are connected in series, and the series-connected resistor and the switch device are arranged in parallel with the battery cell. If the voltage difference between the voltage of a certain battery cell and the voltage of the battery pack 40 is greater than the set voltage difference value, that is, the voltage value of the battery cell is greater than the voltage value of other batteries in the same battery pack 40, the switch device corresponding to the battery cell will be turned on to make the resistor consume the electric energy of the battery cell, thereby reducing the voltage of the battery cell and realizing voltage balancing for the batteries in the same battery pack 40. The switch device is a fully controlled switch device.

[0092] The present invention also proposes a battery module, which includes multiple battery systems as described above; the control modules 20 in the battery system are interconnected and used to output the voltage value of the battery pack 40 in which they are located; the control module 20 is also used to receive the voltage values ​​of other battery packs 40, and determine the voltage value of the battery module based on the voltage values ​​of all battery packs 40.

[0093] It is easy to understand that the control module 20 can determine the voltage value of the battery module according to the voltage values ​​of all battery packs 40 in the battery module. If the control module 20 is a battery management system in the battery pack 40,

[0094] If the control module 20 is a battery management system in a battery pack 40 , the battery management systems in the multiple battery packs 40 of the battery module are electrically connected to each other and communicate with each other to transmit the voltage value of the battery pack 40 in which it is located, and receive the voltage values ​​of other battery packs 40 .

[0095] The specific structure of the battery system refers to the above embodiments. Since the battery module adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0096] The present invention further proposes a battery balancing method, which is applied to the battery system, and includes:

[0097] Obtaining voltage values ​​of the external power source, the battery pack 40 and the battery module;

[0098] Subtract the voltage value of the battery module from the voltage value of the battery pack 40 to obtain a voltage difference;

[0099] If the external power voltage is greater than the first set voltage, the battery module voltage reaches the second set voltage, and the voltage difference is greater than the third set voltage, the DCDC module 30 is controlled to charge the battery pack 40 .

[0100] The battery balancing method determines whether a voltage balancing operation needs to be performed between multiple battery packs 40 in the battery module according to the external power supply voltage, the battery pack 40 voltage and the battery module voltage.

[0101] The battery pack 40 further includes:

[0102] A plurality of battery cells are arranged in series; a resistor and a switch device are arranged in parallel at both ends of each battery cell, and the resistor and the switch device are arranged in series;

[0103] The battery balancing method further includes:

[0104] Detecting voltage values ​​of multiple cells in the battery pack 40;

[0105] If the difference between the cell voltage and the battery pack 40 voltage is greater than the set voltage difference value, the corresponding switch device is controlled to be turned on so that the resistor consumes the electric energy of the cell.

[0106] The battery balancing method also determines whether a voltage balancing operation among multiple battery cells in the battery pack 40 is required based on the voltage value of the battery pack 40 and the voltage values ​​of the battery cells in the battery pack 40 .

[0107] The above descriptions are only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A battery system, characterized in that: The battery system comprises: DCDC module, a battery pack in the battery module, a control module and a voltage detection module; The input end of the DCDC module is connected to the external power supply, and the output end is connected to the battery pack; the voltage detection module is connected to the control module, and is used to detect the voltage value of the external power supply and output it to the control module; The control module is connected to the battery module and the battery pack respectively, and is used to obtain the voltage values ​​of the battery module and the battery pack; The control module is also used to control the DCDC module to operate and charge the battery pack when the external power supply voltage value is greater than the first set voltage value, the battery module voltage is greater than the second set voltage value, and the voltage difference between the battery module and the battery pack is greater than the third set voltage value, so as to reduce the voltage difference between the battery module and the battery pack.

2. The battery system according to claim 1, characterized in that: The battery system further comprises: A first switch device is provided between the DCDC module and the circuit of the battery pack, and is used to control the on / off of the circuit between the DCDC module and the battery pack; the voltage detection module is also connected to the output end of the DCDC module, and is used to detect the voltage output by the DCDC module, and output it to the control module; The control module is connected to the controlled end of the first switch device, and is used to control the first switch device to be turned on when the output voltage of the DCDC module is within a first set voltage range.

3. The battery system according to claim 2, characterized in that: The DCDC module includes: a second switch device and a DCDC circuit; A second switch device is provided in the circuit between the external power supply and the DCDC circuit, and is used to control the on / off of the circuit between the external power supply and the DCDC circuit; The control module is connected to the controlled end of the second switch device, and is used for controlling the second switch device to be turned on so that the DCDC circuit chops the voltage output by the external power supply and then outputs it.

4. The battery system according to claim 3, characterized in that: The DCDC module also includes: a constant current circuit; The input end of the constant current circuit is connected to the output end of the DCDC circuit, and the output end is connected to the first switching device; The constant current circuit is used to transform the current output by the DCDC circuit and to output a constant set current value to charge the battery pack.

5. The battery system according to claim 4, characterized in that: The battery system further comprises: an anti-reverse diode; The anti-reverse diode is arranged in a circuit between the first switching device and the battery pack, wherein an anode of the anti-reverse diode is connected to the first switching device, and a cathode of the anti-reverse diode is connected to the battery pack.

6. The battery system according to any one of claims 1 to 5, characterized in that: The control module is a battery management system in the battery pack.

7. The battery system according to claim 6, characterized in that: The battery pack further comprises: A plurality of battery cells are arranged in series; a resistor and a switch device are arranged in parallel at both ends of each battery cell, and the resistor and the switch device are arranged in series; The battery management system is connected to the controlled ends of all switching devices in the battery pack; the battery management system is used to detect the voltage value of each battery cell, and when the voltage difference between a single battery cell voltage and the battery pack voltage is greater than a set voltage difference value, control the switching device corresponding to the battery cell to turn on, so that the resistor consumes the electric energy of the battery cell, thereby reducing the voltage of the battery cell.

8. A battery module, characterized in that: The battery module includes multiple battery systems as described in any one of claims 1-7; the control modules in the battery system are interconnected and used to output the voltage value of the battery pack in which they are located; the control module is also used to receive the voltage values ​​of other battery packs and determine the voltage value of the battery module based on the voltage values ​​of all battery packs.

9. A battery balancing method, characterized in that: The battery balancing method is applied to the battery system according to any one of claims 1 to 7, and the battery balancing method comprises: Get the voltage values ​​of external power supply, battery pack and battery module; Subtract the voltage value of the battery module from the voltage value of the battery pack to obtain the voltage difference; If the external power supply voltage value is greater than the first set voltage value, the battery module voltage value reaches the second set voltage value, and the voltage difference value is greater than the third set voltage value, the DCDC module is controlled to charge the battery pack.

10. The battery equalization method according to claim 9, characterized in that: The battery pack further comprises: A plurality of battery cells are arranged in series; a resistor and a switch device are arranged in parallel at both ends of each battery cell, and the resistor and the switch device are arranged in series; The battery balancing method further includes: Detect the voltage values ​​of multiple cells in the battery pack; If the difference between the cell voltage and the battery pack voltage is greater than the set voltage difference value, the corresponding switch device is controlled to be turned on so that the resistor consumes the electric energy of the cell.

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