Natural balanced battery management device, system and method

Abstract

The invention discloses a naturally balanced battery management device, system and method, and the device comprises a switching module and an energy storage module. The energy storage module comprises N battery cells and N diode units, and the battery cells are connected with the diode units in series; the switching module is used for switching between a charging loop and a discharging loop; in the charging loop, the N battery cells are in a parallel connection state; and in the discharge loop, the N battery cells are in a series connection state. By adopting the embodiment of the invention, the equalization efficiency can be improved, special equalization time does not need to be consumed, charging time does not need to be prolonged, and an energy transfer circuit and a corresponding failure protection circuit and protection logic do not need to be additionally arranged.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and in particular to a naturally balanced battery management device, system and method. Background Art

[0002] Since there are inevitably certain physical differences between the multiple cells in the battery pack, the electrical parameters of each cell, especially the voltage and internal resistance, will be slightly different during use. In the series battery pack, the cell with the lowest voltage will definitely experience undervoltage protection in advance during discharge, and the cell with the highest voltage will experience overvoltage protection first during charging. At this time, the other cells in the whole pack are not fully utilized or fully charged due to protection. At the same time, due to the influence of this imbalance, after repeated charge and discharge, the weakest cell will age more rapidly, which means that the entire battery pack does not fully utilize its available capacity and shortens its service life.

[0003] Therefore, it is necessary to balance the cells in the battery pack to keep them in relatively consistent working conditions as much as possible, so as to maximize the use of battery capacity and extend battery life. This is where cell balancing technology comes from.

[0004] The current equalization technologies are divided into passive equalization and active equalization, both of which have the following problems:

[0005] (1) It needs to be done at the end of charging, that is, balancing is done when the battery is almost fully charged, and there are other constraints on the start-up balancing conditions, such as the start-up voltage and the cell differential pressure reaching the judgment threshold, the cell temperature being within the allowable range, etc.: Since it is necessary to wait for the conditions for starting balancing to be met, the cells are not balanced during most of the charging time. As the cell capacity becomes larger and larger in actual applications, the time from the completion of the entire charging to the completion of balancing will be quite long. Some batteries even require special maintenance steps to perform balancing due to the long balancing time.

[0006] (2) Due to the existence of energy transfer, it is necessary to add necessary energy transfer circuits and their corresponding failure protection circuits and protection logic: the various losses of energy transfer during the balancing process are actually from the total energy of charging, especially the passive balancing mode has the largest loss, which not only causes energy waste, but also converts the lost energy into heat energy, which is not conducive to charging in a high temperature environment. Furthermore, due to the need for the above-mentioned energy transfer, judgment and protection, the additional circuits and components will inevitably cause cost expenditure. Summary of the invention

[0007] The present application provides a naturally balanced battery management device, system and method to solve the problem in the prior art that an energy transfer circuit and its corresponding failure protection circuit and protection logic need to be added at the charging terminal.

[0008] To achieve the above-mentioned purpose, the embodiment of the present application provides a naturally balanced battery management device, comprising: a switching module and an energy storage module: the energy storage module comprises N battery cells and N diode units, the battery cells and the diode units are connected in series;

[0009] The switching module is used to switch between the charging circuit and the discharging circuit;

[0010] In the charging circuit, N of the battery cells are in parallel connection; in the discharging circuit, N of the battery cells are in series connection.

[0011] As an improvement of the above solution, when the switching module switches to the charging circuit, the charging circuit is in an open state and the discharging circuit is in a closed state, so as to allow N battery cells to be charged through the charging circuit and prevent N battery cells from being discharged through the discharging circuit;

[0012] When the switching module switches to the discharge circuit, the discharge circuit is in an open state and the charging circuit is in a closed state, so as to allow the N battery cells to discharge through the discharge circuit and prevent the N battery cells from being charged through the charging circuit.

[0013] As an improvement of the above solution, the switching module includes N-1 single-pole double-throw switches; the diode unit includes a first diode;

[0014] The fixed end of the n-th single-pole double-throw switch is connected to the negative electrode of the n-th battery cell, the positive electrode of the n-th battery cell is connected to the negative electrode of the n-th first diode, and the positive electrode of the n-th first diode is connected to the positive electrode of the charging circuit; n≤N-1;

[0015] The first active end of the nth single-pole double-throw switch is respectively connected to the positive electrode of the n+1th battery cell and the negative electrode of the n+1th first diode;

[0016] The second active end of the nth single-pole double-throw switch is respectively connected to the negative electrode of the discharge circuit and the negative electrode of the charging circuit;

[0017] The negative electrode of the Nth battery cell is respectively connected to the negative electrode of the discharge circuit and the negative electrode of the charging circuit;

[0018] The positive electrode of the first battery cell is connected to the positive electrode of the discharge circuit.

[0019] As an improvement of the above solution, the switching module includes N-1 single-pole single-throw switches, and the diode unit includes a second diode and a third diode;

[0020] The first end of the nth single-pole single-throw switch is respectively connected to the negative electrode of the nth battery cell and the positive electrode of the nth third diode; the positive electrode of the nth battery cell is connected to the negative electrode of the nth second diode, and the positive electrode of the nth second diode is connected to the positive electrode of the charging circuit; the negative electrode of the nth third diode is connected to the negative electrode of the charging circuit; n≤N-1;

[0021] The second end of the nth single-pole single-throw switch is respectively connected to the positive electrode of the n+1th battery cell and the negative electrode of the n+1th second diode;

[0022] The negative electrode of the Nth battery cell is connected to the positive electrode of the Nth third diode and the negative electrode of the discharge circuit respectively; the negative electrode of the Nth third diode is connected to the negative electrode of the charging circuit;

[0023] The positive electrode of the first battery cell is connected to the positive electrode of the discharge circuit.

[0024] As an improvement of the above solution, the battery management device further includes:

[0025] Control module for:

[0026] When it is detected that the battery management device is connected to an external charger, the switching module is controlled to switch from the discharge circuit to the charging circuit, the charging circuit is controlled to be opened, and the discharge circuit is controlled to be closed, so as to allow the N battery cells to be charged through the charging circuit and prevent the N battery cells from being discharged through the discharge circuit;

[0027] When it is detected that the battery management device is not connected to an external charger or the battery cell is fully charged, the switching module is controlled to switch from the charging circuit to the discharging circuit, the discharging circuit is controlled to be opened, and the charging circuit is controlled to be closed, so as to allow N battery cells to be discharged through the discharging circuit and prevent N battery cells from being charged through the charging circuit.

[0028] To achieve the above objectives, an embodiment of the present application further provides a naturally balanced battery management system, including the above-mentioned naturally balanced battery management device.

[0029] As an improvement of the above solution, the battery management system further includes: an external charger; one end of the external charger is connected to the positive electrode of the charging circuit, and the other end of the external charger is connected to the negative electrode of the charging circuit.

[0030] As an improvement of the above solution, the battery management system further includes: a load; one end of the load is connected to the positive electrode of the discharge circuit, and the other end of the load is connected to the negative electrode of the discharge circuit.

[0031] To achieve the above object, an embodiment of the present application further provides a battery management method, which is applied to the above-mentioned natural balanced battery management device, and the battery management method includes:

[0032] When it is detected that the battery management device is connected to an external charger, the switching module is controlled to switch from the discharge circuit to the charging circuit, the charging circuit is controlled to be opened, and the discharge circuit is controlled to be closed, so as to allow N battery cells to be charged through the charging circuit and prevent N battery cells from being discharged through the discharge circuit.

[0033] As an improvement of the above solution, the battery management method further includes:

[0034] When it is detected that the battery management device is not connected to an external charger or the battery cell is fully charged, the switching module is controlled to switch from the charging circuit to the discharging circuit, the discharging circuit is controlled to be opened, and the charging circuit is controlled to be closed, so as to allow N battery cells to be discharged through the discharging circuit and prevent N battery cells from being charged through the charging circuit.

[0035] Compared with the prior art, the embodiment of the present application provides a naturally balanced battery management device, system and method, which solves the impact problem of mutual charging between cells by switching N cells to a parallel state when charging, and limiting the current of each branch in one direction through a series diode unit. At the same time, the external charging current will be automatically distributed due to the voltage difference of each cell, and a larger current will be allocated to the cell with low voltage and a smaller current to the cell with high voltage, that is, the cell with low cell voltage is charged faster to catch up with the cell with high cell voltage to achieve natural balance. This process does not need to wait for specific start-up balancing conditions to be met before starting, and does not need to wait until the charging end to balance, but naturally completes this process from the beginning of charging, thus saving the time consumed by traditional balancing technology for balancing. Furthermore, since the energy of the high-voltage cell is not moved or consumed in this process, there is no loss of these energies, which is more energy-saving and environmentally friendly. There is no complex energy transfer circuit in the entire circuit design, and there is no need for the failure protection circuit and protection logic corresponding to these added circuits, so it is simpler than the traditional solution, and the cost is naturally significantly reduced. The embodiment of the present application can significantly reduce the overall cost and improve the balancing efficiency. Whether the battery is full or not, it will achieve maximum automatic balancing within this time period, without consuming special balancing time and extending the charging time. In addition, the natural balancing battery management device provided by the embodiment of the present application has wide compatibility, and different battery packs can share a common charger, that is, the charger is of the same low-voltage specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1It is a structural block diagram of a natural balanced battery management device provided in an embodiment of the present application;

[0037] Figure 2 This is a connection method in a charging mode provided in an embodiment of the present application;

[0038] Figure 3 This is a connection method in a discharge mode provided in an embodiment of the present application;

[0039] Figure 4 It is another connection method in a charging mode provided in an embodiment of the present application;

[0040] Figure 5 This is another connection method in a discharge mode provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0042] See also Figure 1 , Figure 1 It is a structural block diagram of a naturally balanced battery management device provided in an embodiment of the present application, wherein the naturally balanced battery management device switching module 11 and the energy storage module 12: the energy storage module 12 comprises N battery cells 121 and N diode units 122, and the battery cells 121 and the diode units 122 are connected in series;

[0043] The switching module 11 is used to switch between the charging circuit and the discharging circuit;

[0044] In the charging circuit, the N battery cells 121 are in parallel connection; in the discharging circuit, the N battery cells 121 are in series connection.

[0045] The embodiment of the present application realizes the switching of the connection state of each battery cell 121 through the switching module 11, which is in series state during discharge and in parallel state during charging. During charging, it is obvious from Kirchhoff's law that each parallel branch will distribute different currents due to different battery cell voltages, and the branch with lower battery cell voltage will get a larger current. This law just meets the need to eliminate the difference between them, so the purpose of balancing between the battery cells 121 is naturally achieved.

[0046] The equalization process of the embodiment of the present application is highly superimposed with the charging process, and is implemented naturally without too much additional circuit assistance. In other words, using traditional equalization technology, charging takes about q time, equalization takes about p time, and the whole process takes about q+p time. Using the embodiment of the present application, charging takes about q time, and the whole process only takes about q time. The embodiment of the present application starts automatic equalization at the beginning of charging, which significantly saves special equalization time.

[0047] The embodiment of the present application does not use an energy acquisition circuit connected across the two ends of the battery cell 121, so there will be no hidden dangers and risks of over-discharge after loss of control. Not only is there no loss of energy, it is more energy-saving and environmentally friendly, but there is also no need for failure protection circuits and protection logic corresponding to these added circuits, which is more concise and significantly reduces costs.

[0048] The embodiment of the present application prevents surge current that may occur due to mutual charging between the battery cells 121 by providing a diode unit 122; and due to the characteristics of the circuit, the diode unit 122 also simplifies and ensures the correct connection of the charging circuit.

[0049] The charging voltage of the embodiment of the present application is low, which makes it easy for battery packs of different specifications to share a charger, fully utilizing resources and reducing the risk of uncontrolled charging.

[0050] The embodiment of the present application does not discharge during charging and does not charge during discharging, thereby avoiding the use scenario of charging and discharging at the same time, reducing the risk of loss of control and extending the life of the battery cell.

[0051] The naturally balanced battery management device provided in the embodiment of the present application has wide compatibility, and different battery packs can share a common charger, that is, the chargers are of the same low-voltage specification.

[0052] In an optional embodiment, when the switching module 11 switches to the charging circuit, the charging circuit is in an open state and the discharging circuit is in a closed state, so as to allow the N battery cells 121 to be charged through the charging circuit and prevent the N battery cells 121 from being discharged through the discharging circuit;

[0053] When the switching module 11 switches to the discharge circuit, the discharge circuit is in an open state and the charging circuit is in a closed state, so as to allow the N battery cells 121 to discharge through the discharge circuit and prevent the N battery cells 121 from charging through the charging circuit.

[0054] In the embodiment of the present application, by putting the discharge circuit and the charge circuit in different states, the charge and discharge of the battery cell 121 are mutually exclusive, thereby avoiding the situation of charging and using at the same time.

[0055] In an optional embodiment, the switching module 11 includes N-1 single-pole double-throw switches; the diode unit 122 includes a first diode;

[0056] The fixed end of the n-th single-pole double-throw switch is connected to the negative electrode of the n-th battery cell 121, the positive electrode of the n-th battery cell 121 is connected to the negative electrode of the n-th first diode, and the positive electrode of the n-th first diode is connected to the positive electrode of the charging circuit; n≤N-1;

[0057] The first active end of the nth single-pole double-throw switch is respectively connected to the positive electrode of the n+1th battery cell 121 and the negative electrode of the n+1th first diode;

[0058] The second active end of the nth single-pole double-throw switch is respectively connected to the negative electrode of the discharge circuit and the negative electrode of the charging circuit;

[0059] The negative electrode of the Nth battery cell 121 is connected to the negative electrode of the discharge circuit and the negative electrode of the charging circuit respectively;

[0060] The positive electrode of the first battery cell 121 is connected to the positive electrode of the discharge circuit.

[0061] For example, take three groups of battery cells 121 as an example. Figure 2-Figure 3 ,include:

[0062] 2 single-pole double-throw switches: the first single-pole double-throw switch SW4 and the second single-pole double-throw switch SW5;

[0063] 3 battery cells 121: the first battery cell B6, the second battery cell B5 and the third battery cell B4;

[0064] Three first diodes: a first first diode D25, a second first diode D24 and a third first diode D23.

[0065] When charging is required, the discharge circuit is switched to the charging circuit. At this time, the cells 121 are connected in series with the first diode and then in parallel. Specifically, the first single-pole double-throw switch SW4 and the second single-pole double-throw switch SW5 are both switched to their respective second active ends 3, so that the fixed ends 2 of the first single-pole double-throw switch SW4 and the second single-pole double-throw switch SW5 are connected to their respective second active ends 3. Figure 2 .

[0066] At this time, the required charging voltage is only slightly higher than the voltage of a group of battery cells 121. The charging current can enter from the positive electrode CH+ of the charging circuit, flow into the positive electrode of the battery cell 121 after passing through the first diode of each branch, and then flow out from the negative electrode of the battery cell 121 and return to the negative electrode CH- of the charging circuit.

[0067] Since each branch has a unidirectional first diode, the charging current from CH+ can smoothly pass through the first diode and charge the battery cell 121, while the battery cell 121 is blocked from discharging externally by the first diode, and there is no path, that is, each branch only has the possibility of current in the charging direction of the battery cell, either there is charging current or there is no current, and there is no current in the discharging direction, so the high-voltage battery cell will not charge the low-voltage battery cell back, and there will be no impact due to the back-injection current when the switch is switched;

[0068] For each branch, the voltage at both ends is the charging circuit voltage, and they are equal. Inside each branch, this voltage is equal to the voltage at both ends of the battery cell 121 and the conduction voltage drop of the first diode, as well as the voltage drop on the total resistance of the branch path. When the battery cell 121 is charging, the voltage U at both ends is the sum of the electromotive force E of the battery cell, the internal resistance R0 of the battery cell and the product I of the charging current (U=E+R0*I). The electromotive force of the battery cell is basically similar to the external voltage of the battery cell when it is stationary, that is, the electromotive force of the battery cell with low voltage will be low at this time, and the difference between the internal resistances of the batteries is temporarily considered to be close (batteries with similar internal resistances will be grouped together during assembly, and the difference in internal resistances of batteries with similar lifespans is not large). Therefore, the charging current of the branch with low battery cell voltage will be larger (when U is equal, the smaller E is, the larger the value of R0*I is, and the larger I is when R0 is similar); the larger the charging current is, the more energy this branch obtains, and naturally the faster its charging speed is, so it will naturally catch up with the branch with small charging current, thereby achieving natural balance.

[0069] In principle, when charging starts, the cells 121 will naturally tend to balance, that is, achieve the purpose of balancing, and this process does not need to wait until the end of charging. This natural balancing process is highly superimposed on the entire charging process, making full use of the charging time and charging energy, and achieving an efficient and energy-saving natural balancing effect.

[0070] When discharge is required, the charging circuit is switched to the discharging circuit. At this time, the connection between the cells 121 is in series, and the voltage between the positive electrode B+ of the discharging circuit / the negative electrode B- of the discharging circuit is the sum of the series connection of the first cell B6, the second cell B5 and the third cell B4. Specifically, the first single-pole double-throw switch SW4 and the second single-pole double-throw switch SW5 are both switched to their respective first active terminals 1, so that the fixed terminals 2 of the first single-pole double-throw switch SW4 and the second single-pole double-throw switch SW5 are both connected to their respective first active terminals 1, see Figure 3 .

[0071] At this time, the current is supplied to the load by the positive pole B+ of the discharge circuit, flows back to the negative pole B- of the discharge circuit after passing through the load, enters the negative pole of the third battery cell B4, and then comes out from the positive pole of the third battery cell B4 through the second single-pole double-throw switch SW4 to the negative pole of the second battery cell B5, and so on until it comes out from the positive pole of the first battery cell B6 to the positive pole B+ of the discharge circuit, completing the entire discharge circuit.

[0072] In the embodiment of the present application, the interfaces of the discharge circuit and the charging circuit are separate and not shared, which makes it easier to achieve charger compatibility and can achieve automatic identification and switching when there is a huge difference between the charging voltage and the discharging voltage.

[0073] In an optional embodiment, the switching module 11 includes N-1 single-pole single-throw switches, and the diode unit 122 includes a second diode and a third diode;

[0074] The first end of the nth single-pole single-throw switch is respectively connected to the negative electrode of the nth battery cell 121 and the positive electrode of the nth third diode; the positive electrode of the nth battery cell 121 is connected to the negative electrode of the nth second diode, and the positive electrode of the nth second diode is connected to the positive electrode of the charging circuit; the negative electrode of the nth third diode is connected to the negative electrode of the charging circuit; n≤N-1;

[0075] The second end of the nth single-pole single-throw switch is respectively connected to the positive electrode of the n+1th battery cell 121 and the negative electrode of the n+1th second diode;

[0076] The negative electrode of the Nth battery cell 121 is connected to the positive electrode of the Nth third diode and the negative electrode of the discharge circuit respectively; the negative electrode of the Nth third diode is connected to the negative electrode of the charging circuit;

[0077] The positive electrode of the first battery cell 121 is connected to the positive electrode of the discharge circuit.

[0078] For example, take three groups of battery cells 121 as an example. Figure 4-Figure 5 ,include:

[0079] 2 single-pole single-throw switches: the first single-pole single-throw switch SW2 and the second single-pole single-throw switch SW3;

[0080] 3 battery cells 121: a first battery cell B1, a second battery cell B2 and a third battery cell B3;

[0081] 3 second diodes: a first second diode D20, a second second diode D21 and a third second diode D22;

[0082] Three third diodes: a first third diode D17, a second third diode D18 and a third third diode D19.

[0083] When charging is required, the discharge circuit is switched to the charging circuit. At this time, the cells 121 are connected in series with the second diode and then in parallel. Specifically, the first single-pole single-throw switch SW2 and the second single-pole single-throw switch SW3 are disconnected. Figure 4 .

[0084] At this time, the required charging voltage is only slightly higher than the voltage of a group of battery cells 121 to achieve charging. The charging current can enter from the positive electrode CH+ of the charging circuit, flow into the positive electrode of the battery cell 121 after passing through the second diode of each branch, and then flow out from the negative electrode of the battery cell 121 to the positive electrode of the third diode, and return to the negative electrode CH- of the charging circuit from the negative electrode of the third diode.

[0085] Since each branch has a unidirectional second diode, the charging current from CH+ can smoothly pass through the second diode and charge the battery cell 121, while the battery cell 121 is blocked from discharging externally by the second diode, and there is no path, that is, each branch only has the possibility of charging current for the battery cell 121, either there is charging current or there is no current, and there is no discharge current, so the high voltage battery cell 121 will not charge the low voltage battery cell 121 back, and there will be no impact due to the back current when the switch is switched;

[0086] For each branch, the voltage at both ends is the charging circuit voltage, and they are equal. Inside each branch, this voltage is equal to the voltage at both ends of the battery cell 121 and the conduction voltage drop of the first diode, as well as the voltage drop on the total resistance of the branch path. When the battery cell 121 is charging, the voltage U at both ends is the sum of the electromotive force E of the battery cell, the internal resistance R0 of the battery cell and the product I of the charging current (U=E+R0*I). The electromotive force of the battery cell is basically similar to the external voltage of the battery cell when it is stationary, that is, the electromotive force of the battery cell with low voltage will be low at this time, and the difference between the internal resistances of the batteries is temporarily considered to be close (batteries with similar internal resistances will be grouped together during assembly, and the difference in internal resistances of batteries with similar lifespans is not large). Therefore, the charging current of the branch with low battery cell voltage will be larger (when U is equal, the smaller E is, the larger the value of R0*I is, and the larger I is when R0 is similar); the larger the charging current is, the more energy this branch obtains, and naturally the faster its charging speed is, so it will naturally catch up with the branch with small charging current, thereby achieving natural balance.

[0087] When discharge is required, the charging circuit is switched to the discharging circuit. At this time, the connection between the battery cells 121 is in series, and the voltage between the positive electrode B+ of the discharging circuit / the negative electrode B- of the discharging circuit is the sum of the series connection of the first battery cell B1, the second battery cell B2 and the third battery cell B3. Specifically, the first single-pole single-throw switch SW2 is connected to the second single-pole single-throw switch SW3.

[0088] At this time, the current is supplied to the load by the positive electrode B+ of the discharge circuit, flows back to the negative electrode B- of the discharge circuit after passing through the load, enters the negative electrode of the third battery cell B3, and then flows into the negative electrode of the second battery cell B2 from the two single-pole single-throw switches SW5, and so on until it comes out from the positive electrode of the first battery cell B1 to the positive electrode B+ of the discharge circuit, completing the entire discharge circuit, as shown in FIG. Figure 5 .

[0089] In the embodiment of the present application, the interfaces of the discharge circuit and the charging circuit are separate and not shared, which makes it easier to achieve charger compatibility and can achieve automatic identification and switching when there is a huge difference between the charging voltage and the discharging voltage.

[0090] Figure 2-Figure 5 The difference is the switch used. Figure 4 and Figure 5 A single-pole single-throw switch is used, but an additional diode is added in the charging branch. The circuit switching is simple, but due to the additional diode, the charging loss will increase slightly due to the forward conduction voltage drop of the diode. Figure 2 and Figure 3 There is one less diode, but the switching switch needs to use a single-pole double-throw switch, and the switching circuit will be complicated.

[0091] The types of the first diode, the second diode, and the third diode may be the same or different. A diode with a low forward voltage drop may be selected to improve the charging efficiency. For example, the forward conduction voltage of an ordinary silicon diode is about 0.7V. For example, the cell voltage of a ternary lithium battery is about 3.6V, so the charging efficiency is 3.6 / (3.6+0.7)=83.7%. If a high-efficiency synchronous rectifier diode IC is selected, the forward voltage drop can be lower than 0.1V, and the efficiency is 3.6 / (3.6+0.1)=97.3%. It can be seen that the efficiency of different diodes varies significantly, and can be selected based on cost and performance.

[0092] In addition, the switching module 11 of the embodiment of the present application can also be of other types, such as a mechanical switch, such as a self-locking bi-stable relay (a relay that switches when powered on and maintains the state after power failure); an electronic switch, such as a power semiconductor switch, can also be used. The mechanical switch circuit is simple, with high voltage resistance and good weather resistance, but the contact resistance is larger than that of the semiconductor electronic switch, and the switching mechanism has a limited life; the electronic switch has a small on-resistance and can pass large currents, but the voltage resistance is lower than that of the mechanical switch, and the drive circuit is relatively complex, and can also be selected based on cost and application indicators.

[0093] In an optional embodiment, the battery management device further includes:

[0094] Control module for:

[0095] When it is detected that the battery management device is connected to an external charger, the switching module 11 is controlled to switch from the discharge circuit to the charging circuit, the charging circuit is controlled to be opened, and the discharge circuit is controlled to be closed, so as to allow the N battery cells 121 to be charged through the charging circuit and prevent the N battery cells 121 from being discharged through the discharge circuit;

[0096] When it is detected that the battery management device is not connected to an external charger or the battery cell 121 has been charged, the switching module 11 is controlled to switch from the charging circuit to the discharging circuit, the discharging circuit is controlled to be opened, and the charging circuit is controlled to be closed, so as to allow N battery cells 121 to discharge through the discharging circuit and prevent N battery cells 121 from being charged through the charging circuit.

[0097] In the embodiment of the present application, when the control module detects that the battery management device is connected to an external charger, it indicates that there is an intention to charge. At this time, the switching module 11 is controlled to switch from the discharge circuit to the charging circuit, the charging circuit is controlled to be opened, and the discharge circuit is controlled to be closed, so as to allow N of the battery cells 121 to be charged through the charging circuit and prevent N of the battery cells 121 from being discharged through the discharge circuit. Specifically, when it is detected that the battery management device is connected to an external charger, the discharge circuit is closed, and after the discharge current drops to 0, the switching module 11 is controlled to switch, so that the battery cells 121 are connected in parallel; after confirming that the switching is completed and stable, the charging circuit is opened, that is, the external charging circuit is connected to CH+ / CH- to allow the charging current of the charger to be sent to each parallel branch.

[0098] At this time, the charging current is applied to each battery cell 121 branch through the charging circuit trunk line, and different charging currents are obtained according to the differences in electrical characteristics of each branch. As mentioned above, the battery cell 121 branch with a lower voltage will obtain a larger charging current. As the voltage increases, the difference between the battery cells 121 will also decrease, and the charging currents obtained will tend to be balanced. This process naturally eliminates the differences between the battery cells 121 and achieves the purpose of balancing the battery cells 121.

[0099] When the control module detects that charging is complete or that the battery management device is not connected to an external charger, there is no loop between B+ / B-, and the circuit is still in charging mode. The discharge port is not open, so there is no discharge current. At this time, the switch is executed, and the battery cell 121 changes to the series mode. After confirming that the switch is completed, B+ / B- is the total voltage of the battery cell 121 after the series connection. At this time, the battery pack is ready to discharge. The discharge port can be controlled to supply power to the outside according to the external load status, including load connection or pre-discharge judgment, or the strategy of allowing discharge.

[0100] In addition, an embodiment of the present application also provides a naturally balanced battery management system, including the naturally balanced battery management device described in any of the above embodiments.

[0101] Optionally, the battery management system further includes: an external charger; one end of the external charger is connected to the positive pole of the charging circuit, and the other end of the external charger is connected to the negative pole of the charging circuit.

[0102] Optionally, the battery management system further includes: a load; one end of the load is connected to the positive electrode of the discharge circuit, and the other end of the load is connected to the negative electrode of the discharge circuit.

[0103] It is worth noting that the working process of the naturally balanced battery management system described in the embodiment of the present application can refer to the working process of the naturally balanced battery management device described in the above embodiment, which will not be repeated here.

[0104] In addition, an embodiment of the present application further provides a battery management method, which is applied to the natural balanced battery management device described in any of the above embodiments, and the battery management method includes:

[0105] When it is detected that the battery management device is connected to an external charger, the switching module is controlled to switch from the discharge circuit to the charging circuit, the charging circuit is controlled to be opened, and the discharge circuit is controlled to be closed, so as to allow N battery cells to be charged through the charging circuit and prevent N battery cells from being discharged through the discharge circuit.

[0106] Optionally, the battery management method further includes:

[0107] When it is detected that the battery management device is not connected to an external charger or the battery cell is fully charged, the switching module is controlled to switch from the charging circuit to the discharging circuit, the discharging circuit is controlled to be opened, and the charging circuit is controlled to be closed, so as to allow N battery cells to be discharged through the discharging circuit and prevent N battery cells from being charged through the charging circuit.

[0108] It is worth noting that the working process of the naturally balanced battery management method described in the embodiment of the present application can refer to the working process of the naturally balanced battery management device described in the above embodiment, which will not be repeated here.

[0109] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A naturally balanced battery management device, characterized in that: include: Switching module and energy storage module: the energy storage module includes N battery cells and N diode units, the battery cells and the diode units are connected in series; The switching module is used to switch between the charging circuit and the discharging circuit; In the charging circuit, N of the battery cells are in parallel connection; in the discharging circuit, N of the battery cells are in series connection.

2. The natural balanced battery management device according to claim 1, characterized in that: When the switching module switches to the charging circuit, the charging circuit is in an open state and the discharging circuit is in a closed state, so as to allow the N battery cells to be charged through the charging circuit and prevent the N battery cells from being discharged through the discharging circuit; When the switching module switches to the discharge circuit, the discharge circuit is in an open state and the charging circuit is in a closed state, so as to allow the N battery cells to discharge through the discharge circuit and prevent the N battery cells from being charged through the charging circuit.

3. The natural balanced battery management device according to any one of claims 1 to 2, characterized in that: The switching module includes N-1 single-pole double-throw switches; the diode unit includes a first diode; The fixed end of the n-th single-pole double-throw switch is connected to the negative electrode of the n-th battery cell, the positive electrode of the n-th battery cell is connected to the negative electrode of the n-th first diode, and the positive electrode of the n-th first diode is connected to the positive electrode of the charging circuit; n≤N-1; The first active end of the nth single-pole double-throw switch is respectively connected to the positive electrode of the n+1th battery cell and the negative electrode of the n+1th first diode; The second active end of the nth single-pole double-throw switch is respectively connected to the negative electrode of the discharge circuit and the negative electrode of the charging circuit; The negative electrode of the Nth battery cell is respectively connected to the negative electrode of the discharge circuit and the negative electrode of the charging circuit; The positive electrode of the first battery cell is connected to the positive electrode of the discharge circuit.

4. The naturally balanced battery management device according to any one of claims 1 to 2, characterized in that: The switching module includes N-1 single-pole single-throw switches, and the diode unit includes a second diode and a third diode; The first end of the nth single-pole single-throw switch is respectively connected to the negative electrode of the nth battery cell and the positive electrode of the nth third diode; the positive electrode of the nth battery cell is connected to the negative electrode of the nth second diode, and the positive electrode of the nth second diode is connected to the positive electrode of the charging circuit; the negative electrode of the nth third diode is connected to the negative electrode of the charging circuit; n≤N-1; The second end of the nth single-pole single-throw switch is respectively connected to the positive electrode of the n+1th battery cell and the negative electrode of the n+1th second diode; The negative electrode of the Nth battery cell is connected to the positive electrode of the Nth third diode and the negative electrode of the discharge circuit respectively; the negative electrode of the Nth third diode is connected to the negative electrode of the charging circuit; The positive electrode of the first battery cell is connected to the positive electrode of the discharge circuit.

5. The natural balanced battery management device according to any one of claims 1 to 2, characterized in that: The battery management device further comprises: Control module for: When it is detected that the battery management device is connected to an external charger, the switching module is controlled to switch from the discharge circuit to the charging circuit, the charging circuit is controlled to be opened, and the discharge circuit is controlled to be closed, so as to allow the N battery cells to be charged through the charging circuit and prevent the N battery cells from being discharged through the discharge circuit; When it is detected that the battery management device is not connected to an external charger or the battery cell is fully charged, the switching module is controlled to switch from the charging circuit to the discharging circuit, the discharging circuit is controlled to be opened, and the charging circuit is controlled to be closed, so as to allow N battery cells to be discharged through the discharging circuit and prevent N battery cells from being charged through the charging circuit.

6. A naturally balanced battery management system, characterized in that: A naturally balanced battery management device comprising the battery management device as described in any one of claims 1-5.

7. The natural balanced battery management system according to claim 6, characterized in that: The battery management system further includes: an external charger; one end of the external charger is connected to the positive electrode of the charging circuit, and the other end of the external charger is connected to the negative electrode of the charging circuit.

8. The natural balanced battery management system according to claim 6, characterized in that: The battery management system further includes: a load; one end of the load is connected to the positive electrode of the discharge circuit, and the other end of the load is connected to the negative electrode of the discharge circuit.

9. A battery management method, characterized in that: Applied to the natural balanced battery management device as claimed in any one of claims 1 to 5, the battery management method comprises: When it is detected that the battery management device is connected to an external charger, the switching module is controlled to switch from the discharge circuit to the charging circuit, the charging circuit is controlled to be opened, and the discharge circuit is controlled to be closed, so as to allow N battery cells to be charged through the charging circuit and prevent N battery cells from being discharged through the discharge circuit.

10. The battery management method according to claim 9, characterized in that: The battery management method further comprises: When it is detected that the battery management device is not connected to an external charger or the battery cell is fully charged, the switching module is controlled to switch from the charging circuit to the discharging circuit, the discharging circuit is controlled to be opened, and the charging circuit is controlled to be closed, so as to allow N battery cells to be discharged through the discharging circuit and prevent N battery cells from being charged through the charging circuit.

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