Battery management device, battery pack and power consumption device

Abstract

A battery management device includes a charging switch, a discharging switch, a DC-DC converter, an integrated circuit, a first pre-discharge circuit, and a second pre-discharge circuit. The charging switch, the discharging switch, and the DC-DC converter are arranged on a main circuit, and the charging switch, the discharging switch, and the DC-DC converter are connected in series. The integrated circuit is electrically connected to the charging switch, the discharging switch, and the DC-DC converter, respectively, and is configured to control the charging switch, the discharging switch, and the DC-DC converter. The first pre-discharge circuit is configured to have one end electrically connected to the positive electrode of the battery module and the other end electrically connected to the positive output terminal. The first pre-discharge circuit is connected in parallel with the first path where the charging switch, the discharging switch, and the DC-DC converter are located. The second pre-discharge circuit is connected in parallel with the discharge switch, and the integrated circuit is electrically connected to the first pre-discharge circuit and the second pre-discharge circuit, respectively.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of battery technology, and in particular to a battery management device, a battery pack, and an electrical device. Background Art

[0002] Second-life batteries refer to batteries that have been retired from new energy equipment such as electric vehicles and energy storage systems. Although second-life batteries do not meet the driving requirements of high-power devices, they still have considerable remaining capacity and service life. Related technologies boost the voltage of second-life batteries and transmit the boosted voltage to the load to drive the load to work, thereby realizing the secondary use of second-life batteries. Summary of the invention

[0003] One purpose of the embodiments of the present application is to provide a battery management device, a battery pack and an electrical device to improve the technical problem of high power consumption in related technologies.

[0004] In the first aspect, an embodiment of the present application provides a battery management device, including a charging switch, a discharging switch, a DC-DC converter, an integrated circuit, a first pre-discharge circuit and a second pre-discharge circuit, wherein the charging switch, the discharging switch and the DC-DC converter are arranged on the main circuit, and the charging switch, the discharging switch and the DC-DC converter are connected in series. The integrated circuit is electrically connected to the charging switch, the discharging switch and the DC-DC converter, respectively, and is configured to control the charging switch, the discharging switch and the DC-DC converter. The first pre-discharge circuit is configured such that one end thereof is electrically connected to the positive electrode of the battery module, and the other end thereof is electrically connected to the positive output terminal, and the first pre-discharge circuit is connected in parallel to the first path where the charging switch, the discharging switch and the DC-DC converter are located. The second pre-discharge circuit is connected in parallel to the discharge switch; wherein the integrated circuit is electrically connected to the first pre-discharge circuit and the second pre-discharge circuit, respectively.

[0005] In an embodiment of the present application, on the one hand, when the battery management device enters or is in a sleep state, the first pre-discharge circuit consumes less power than the DC-DC converter when connected to the load of the electrical equipment, controls the DC-DC converter not to work, reduces the power consumption of the DC-DC converter, controls the first pre-discharge circuit to enter a working state, and reduces the power consumption of the battery cell module.

[0006] Before the battery cell module enters the discharge state, before controlling the charging switch and the discharging switch to close, the second pre-discharge circuit is controlled to work first, and the discharge current charges the input capacitor and the output capacitor of the DC-DC converter through the second pre-discharge circuit, so as to avoid excessive short-circuit current when the input capacitor and the output capacitor of the DC-DC converter are not charged in advance and are instantly powered on, so as to avoid excessive short-circuit current from impacting the battery cell module and the input capacitor, output capacitor and switch in the DC-DC converter.

[0007] In one or more embodiments, the first path is arranged between the positive electrode and the positive output terminal of the battery module; the discharge switch is arranged on the first side of the DC-DC converter, and the charging switch is arranged on the second side of the DC-DC converter; wherein the first side of the DC-DC converter is configured to be closer to the positive electrode of the battery module than the second side of the DC-DC converter.

[0008] When a short circuit occurs between the positive output terminal P+ and the negative output terminal P- of the battery pack, or a short circuit occurs in the DC-DC converter, or an abnormality occurs in the circuit before the first side of the DC-DC converter, the integrated circuit controls the discharge switch to turn off, cutting off the short-circuit current, thereby protecting the cascade battery module in a timely manner.

[0009] In one or more embodiments, the number of discharge switches is N, and the N discharge switches are connected in parallel; the number of charge switches is M, and the M charge switches are connected in parallel; wherein M is less than N, and both M and N are positive integers. The embodiment of the present application saves design cost by using fewer charge switches.

[0010] In one or more embodiments, the battery management device also includes a current sensor and a current detection circuit, which are arranged on the main circuit, and the current sensor and the current detection circuit are electrically connected to the integrated circuit; the current sensor is arranged on the first side of the DC-DC converter, and the current detection circuit is arranged on the second side of the DC-DC converter; wherein the first side of the DC-DC converter is configured to be closer to the positive pole of the battery module than the second side of the DC-DC converter.

[0011] In one or more embodiments, the integrated circuit includes an analog front-end chip and a micro control unit; the current sensor and the current detection circuit are both electrically connected to the analog front-end chip; or, the current sensor and the current detection circuit are both electrically connected to the micro control unit; or, the current sensor is electrically connected to the analog front-end chip, and the current detection circuit is electrically connected to the micro control unit.

[0012] In one or more embodiments, the first preamplifier circuit includes: a first preamplifier switch, a first resistor and a boost circuit, the first preamplifier switch, the first resistor and the boost circuit are connected in series, and the integrated circuit is electrically connected to the first preamplifier switch and the boost circuit respectively; the second preamplifier circuit includes: a second preamplifier switch and a second resistor, the second preamplifier switch and the second resistor are connected in series, and the integrated circuit is electrically connected to the second preamplifier switch.

[0013] In one or more embodiments, the integrated circuit includes an analog front-end chip and a microcontroller unit; the analog front-end chip is electrically connected to the charging switch and the discharging switch, respectively, and the microcontroller unit is electrically connected to the first pre-release switch and the second pre-release switch, respectively; or, the analog front-end chip is electrically connected to the charging switch and the discharging switch, respectively; and the microcontroller unit is electrically connected to the first pre-release switch, the second pre-release switch, the charging switch, and the discharging switch, respectively.

[0014] In one or more embodiments, the integrated circuit includes a microcontroller unit, which is electrically connected to a DC-DC converter; the DC-DC converter includes an energy storage unit and a DC-DC conversion unit, the energy storage unit includes a first capacitor and a second capacitor, the first capacitor is arranged between the DC-DC conversion unit and the discharge switch, the first end of the first capacitor is electrically connected to the main circuit, and the second end of the first capacitor is electrically connected to the ground; the second capacitor is arranged between the DC-DC conversion unit and the charging switch, the first end of the second capacitor is electrically connected to the main circuit, and the second end of the second capacitor is electrically connected to the ground; the DC-DC conversion unit is electrically connected between the main circuit and the ground.

[0015] In one or more embodiments, the DC-DC converter includes a single-phase boost-buck circuit or a multi-phase interleaved parallel boost-buck circuit.

[0016] In one or more embodiments, the battery management device further includes a wake-up circuit, which is electrically connected to the first pre-discharge circuit and the integrated circuit respectively.

[0017] In a second aspect, an embodiment of the present application provides a battery pack, including a cascade battery cell module and the above-mentioned battery management device; the cascade battery cell module includes a plurality of battery cells, and a full charge capacity of at least one of the plurality of battery cells is less than a rated capacity.

[0018] In a third aspect, an embodiment of the present application provides an electrical device, including a load and the above-mentioned battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by the figures in the accompanying drawings, which are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.

[0020] Figure 1 A schematic diagram of the structure of a battery pack provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of the circuit structure of a battery management device provided in an embodiment of the present application;

[0022] Figure 3 A schematic diagram of the circuit structure of a battery management device provided in another embodiment of the present application is shown in FIG. Figure 3The battery management device shown in Figure 2 On the basis of the invention, a first preamplifier circuit and a second preamplifier circuit are additionally provided;

[0023] Figure 4 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Figure 4 The battery management device shown in Figure 3 On the basis of increasing the number of discharge switches and charging switches;

[0024] Figure 5 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Figure 5 The battery management device shown in Figure 4 Add a current sensor on the basis of

[0025] Figure 6 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Figure 6 The battery management device shown in Figure 5 Add current detection circuit on the basis of

[0026] Figure 7 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Figure 7 The battery management device shown in Figure 6 On this basis, the circuit structure of the current detection circuit is refined;

[0027] Figure 8 This is a schematic diagram of the circuit structure of a battery management device provided by yet another embodiment of the present application, wherein the current sensor and the current detection circuit are both electrically connected to the analog front-end chip;

[0028] Fig. 9 This is a schematic diagram of the circuit structure of a battery management device provided by yet another embodiment of the present application, wherein the current sensor and the current detection circuit are both electrically connected to the micro control unit;

[0029] Fig.10 This is a schematic diagram of the circuit structure of a battery management device provided by yet another embodiment of the present application, wherein the current sensor is electrically connected to the analog front-end chip, and the current detection circuit is electrically connected to the micro control unit;

[0030] Fig.11 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Fig.11 The battery management device shown in Fig.10 On the basis of the above, the circuit structure of the first preamplifier circuit is refined;

[0031] Fig.12 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Fig.12 The battery management device shown in Fig.11 On the basis of the above, an energy storage unit is additionally provided, and the energy storage unit includes a first capacitor and a second capacitor;

[0032] Fig.13 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Fig.13 The battery management device shown in Fig.12 On the basis of the above, the circuit structure of the second preamplifier circuit is refined;

[0033] Fig.14 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Fig.14 The battery management device shown in Fig.13 On the basis of adding the first AND gate and the second AND gate;

[0034] Fig.15 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Fig.15 The battery management device shown in Fig.14 On the basis of adding a temperature sampling circuit;

[0035] Fig.16 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Fig.15 The battery management device shown in Fig.14 Based on the above, the circuit structure of the DC-DC converter is refined. The DC-DC converter includes 4 DC-DC conversion units;

[0036] Fig.17 A schematic diagram of a specific circuit structure of a battery management device provided in yet another embodiment of the present application;

[0037] Fig.18 for Fig.17 The switching timing diagram of the first switch in the four DC-DC conversion units shown;

[0038] Fig.19 for Fig.17 The switching timing diagram of the second switch in the four DC-DC conversion units shown;

[0039] Fig. 20 This is a schematic diagram of the circuit structure of a battery management device provided in yet another embodiment of the present application. Fig. 20 The battery management device shown in Fig.16 Add a wake-up circuit on the basis of

[0040] Fig.21 This is a schematic diagram of a specific circuit structure of a battery management device provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as there is no structural conflict between them.

[0043] Hereinafter, an embodiment of the present application provides a battery pack, which is applied to an electric device, the electric device includes a load and a battery pack, and the battery pack provides power to the load. It is understandable that the product forms of the electric device are relatively diverse, including electric vehicles, energy storage systems, drones, electric tools, etc. Electric vehicles include electric two-wheelers, electric tricycles, electric vehicles, etc.

[0044] See also Figure 1 The battery pack 100 includes a secondary battery cell module 200 and a battery management device 300 , and the battery management device 300 is electrically connected to the secondary battery cell module 200 .

[0045] The second-life battery module 200 includes a plurality of battery cells, and the full charge capacity of at least one of the plurality of battery cells is less than the rated capacity. The rated capacity is the capacity of a normal battery cell in a fully charged state, and the full charge capacity is the maximum capacity of the current battery cell in a fully charged state. When the full charge capacity of a battery cell is less than the rated capacity, the performance of the battery cell decreases relative to the performance of a normal battery cell, and the battery cell is used as a second-life battery.

[0046] During the secondary use of the used battery module 200, in some embodiments, all the batteries in the used battery module 200 are used batteries. In some embodiments, some batteries in the used battery module 200 are used batteries, and the other batteries are normal batteries. The battery management device 300 is used to manage the charging and discharging of the used battery module 200.

[0047] See also Figure 2 The battery management device 300 includes a charging switch 31 , a discharging switch 32 and a DC-DC converter 33 .

[0048] The charging switch 31 and the discharging switch 32 are arranged on the main circuit 30a, and the secondary battery module 200 provides electric energy to the load through the main circuit 30a. In some embodiments of the present application, the discharging switch 32 and the charging switch 31 are electronic switch tubes or relays, and the electronic switch tubes include triodes, metal-oxide-semiconductor field effect transistors (Metal-Oxid-Semiconductor Field-Effect Transistor, MOSFET), insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT), etc.

[0049] The DC-DC converter 33 is disposed on the main circuit 30a, and the charging switch 31, the discharging switch 32 and the DC-DC converter 33 are connected in series. In some embodiments, the DC-DC converter 33 is a BUCK-BOOST converter.

[0050] Please continue reading Figure 2 The battery management device 300 includes an integrated circuit 34, which is electrically connected to the charging switch 31, the discharging switch 32 and the DC-DC converter 33 respectively, and is used to control the charging switch 31, the discharging switch 32 and the DC-DC converter 33.

[0051] In some embodiments, the battery pack enters or is in a discharging state, the integrated circuit 34 controls the charging switch 31 and the discharging switch 32 to close, so that the charging switch 31 and the discharging switch 32 enter the working state, and controls the DC-DC converter 33 to enter the boost state, and the electric energy output by the ladder battery module 200 is transmitted to the load through the charging switch 31, the discharging switch 32 and the DC-DC converter 33. Specifically, the DC-DC converter 33 boosts the voltage provided by the ladder battery module 200 and transmits it to the load in the electrical equipment, such as the motor, instrument, lamp, horn, etc. in the electric tricycle. As a specific example, the output voltage of the ladder battery module 200 is 40V, and the integrated circuit 34 controls the DC-DC converter 33 to perform a boost operation to increase the 40V voltage of the ladder battery module 200 to 60V.

[0052] In some embodiments, when the battery pack enters or is in a charging state, the integrated circuit 34 controls the charging switch 31 and the discharging switch 32 to close, so that the charging switch 31 and the discharging switch 32 enter the working state, and controls the DC-DC converter 33 to enter the step-down state, and the electric energy provided by the charging device is transmitted to the ladder battery module 200 through the charging switch 31, the DC-DC converter 33 and the discharging switch 32 to charge the ladder battery module 200. Specifically, the DC-DC converter 33 steps down the voltage provided by the charging device and transmits it to the ladder battery module 200. For example, the output voltage of the charging device is 60V, and the integrated circuit 34 controls the DC-DC converter 33 to perform a constant current step-down operation to reduce the 60V voltage output by the charging device to the voltage of the battery pack to charge the ladder battery module 200.

[0053] See also Figure 3 The battery management device 300 includes a first pre-discharge circuit 35, one end of which is electrically connected to the positive electrode B+ of the battery module, and the other end is electrically connected to the positive output terminal P+. It can be understood that the battery module is a ladder cell module 200, and the positive output terminal P+ is the positive terminal of the ladder cell module 20 to output power to the load.

[0054] The first preamplifier circuit 35 is connected in parallel with the first path 30b where the charging switch 31, the discharging switch 32 and the DC-DC converter 33 are located. The integrated circuit 34 is electrically connected to the first preamplifier circuit 35 to control the working state of the first preamplifier circuit 35.

[0055] In some embodiments, the battery management device enters or is in a sleep state, the integrated circuit 34 controls the first pre-discharge circuit 35 to work, controls the charging switch 31, the discharging switch 32, and the DC-DC converter 33 on the first path 30b to stop working, and the current of the cascade battery module 200 is transmitted to the positive output terminal P+ through the first pre-discharge circuit 35, and then transmitted to the load of the electrical equipment through the positive output terminal P+, thereby maintaining the operation of the battery management device in the sleep state.

[0056] In the embodiment of the present application, when the battery management device is in a sleep state, the first pre-discharge circuit consumes less power than the DC-DC converter when connected to the load of the electrical equipment, controls the DC-DC converter not to work, reduces the power consumption of the DC-DC converter, controls the first pre-discharge circuit to enter a working state, and reduces the power consumption of the cascade battery cell module.

[0057] In some embodiments, before the cascade battery cell module 200 enters the discharge state, the integrated circuit first controls the first pre-discharge circuit 35 to be in a working state, and the cascade battery cell module 200 charges the load capacitor at the end of the electrical device, thereby preventing the integrated circuit 34 from directly controlling the discharge switch 32 and the charging switch 31 to enter the working state, thereby instantaneously generating excessive short-circuit current.

[0058] In some embodiments, the battery management device enters or is in a sleep state, the first pre-amplifier circuit 35 is electrically connected to the transistor and the comparator, the comparator is electrically connected to the integrated circuit, and when the first pre-amplifier circuit 35 is in a working state and the current flowing through the first pre-amplifier circuit 35 exceeds a certain value, the integrated circuit is awakened, and then the battery management device is awakened.

[0059] Please continue reading Figure 3 The battery management device 300 further includes a second pre-discharge circuit 36 ​​, which is connected in parallel with the discharge switch 32 , and the integrated circuit 34 is electrically connected to the second pre-discharge circuit 36 ​​.

[0060] In some embodiments, when the battery pack enters or is in a pre-discharge state, the integrated circuit 34 controls the second pre-discharge circuit 36 ​​to operate before controlling the charging switch 31 and the discharging switch 32 to close. The discharge current charges the input capacitor and the output capacitor in the DC-DC converter 33 through the second pre-discharge circuit 36, thereby preventing the input capacitor and the output capacitor of the DC-DC converter 33 from being energized instantly without being charged in advance and preventing excessive short-circuit current from impacting the secondary battery module 200 and the input capacitor, output capacitor, and switch in the DC-DC converter 33.

[0061] Please continue reading Figure 3 , the first path 30b is provided between the positive electrode B+ and the positive output terminal P+ of the ladder battery module 200. The discharge switch 32 is provided on the first side 33a of the DC-DC converter 33, and the charging switch 31 is provided on the second side 33b of the DC-DC converter 33. The first side of the DC-DC converter 33 is closer to the positive electrode B+ of the ladder battery module 200 than the second side 33b of the DC-DC converter 33.

[0062] It is understandable that if the discharge switch 32 is provided on the second side 33b of the DC-DC converter 33, and the charging switch 31 is provided on the first side 33a of the DC-DC converter 33, when a short circuit occurs in the DC-DC converter 33 or an abnormality occurs in the circuit on the first side 33a of the DC-DC converter 33, if the charging switch 31 is a semiconductor field effect transistor, because the charging switch 31 includes a body diode, disconnecting the discharge switch 32 or disconnecting the charging switch 31 cannot shield the effect of the short circuit on the cascade battery module 200, and the short-circuit current cannot be cut off. In the above situation, the large current caused by the short circuit triggers the fuse of the battery management device to cut off the short-circuit current, thereby protecting the cascade battery module 200. However, after the fuse is activated, it is necessary to manually install the fuse or manually restart the fuse.

[0063] In some embodiments of the present application, the discharge switch 32 is arranged on the first side 33a of the DC-DC converter 33, and the charging switch 31 is arranged on the second side 33b of the DC-DC converter 33. When a short circuit occurs in the DC-DC converter 33 or an abnormality occurs in the circuit located on the first side 33a of the DC-DC converter 33, the integrated circuit 34 controls the discharge switch 32 to enter the disconnected state, cutting off the excessive short-circuit current, thereby providing more timely and comprehensive protection for the battery pack 100.

[0064] See also Figure 4 , the number of discharge switches 32 is N, N discharge switches 32 are connected in parallel, and N is a positive integer. If a single discharge switch 32 is used to receive and transmit the current of the ladder battery module 200, since the current of the ladder battery module 200 is relatively large, for example, the current reaches 40A, the current stress on the single discharge switch 32 is relatively large, which makes it difficult to select the discharge switch, and the large current stress is easy to damage the discharge switch 32. In the embodiment of the present application, multiple discharge switches 32 are provided, and the multiple discharge switches 32 shunt the current of the ladder battery module 200, effectively alleviating the current stress on the single discharge switch 32, which is conducive to reducing the design difficulty and improving the working stability and reliability of the discharge switch 32.

[0065] Please continue reading Figure 4 , the number of charging switches 31 is M, M charging switches 31 are connected in parallel, and M is a positive integer. As described above, the embodiment of the present application is provided with multiple charging switches 31, and the current flowing through the multiple charging switches 31 on the main circuit is divided, which effectively alleviates the current stress on a single charging switch 31, which is conducive to reducing the design difficulty and improving the working stability and reliability of the charging switch 31.

[0066] As mentioned above, if the discharge switch 32 is disposed on the second side 33b of the DC-DC converter 33 and the charging switch 31 is disposed on the first side 33a of the DC-DC converter 33, there is a risk that the short-circuit current cannot be turned off. However, if both the discharge switch 32 and the charging switch 31 are disposed on the first side 33a of the DC-DC converter 33, there are also the following disadvantages: the number of the discharge switches 32 and the number of the charging switches 31 need to be consistent, for example, N=M needs to be maintained, resulting in an increase in the cost of the battery pack.

[0067] For example, the output voltage of the ladder battery module 200 is 40V, and the integrated circuit 34 controls the DC-DC converter 33 to perform a boost operation to increase the 40V voltage of the ladder battery module 200 to 60V. After the battery pack is connected to the electrical equipment, it discharges the load of the electrical equipment. If the current required by the load is 40A, ignoring the energy loss caused by energy efficiency conversion, the ladder battery module 200 outputs a corresponding current of 60A, so that both the charging switch 31 and the discharging switch 32 need to withstand a current of 60A, that is, the number of charging switches 31 needs to be set equal to the number of discharging switches 32. It is understandable that in this scenario, the current of the first side 33a of the DC-DC converter 33 is 60A, which is greater than the current of 40A on the second side 33b of the DC-DC converter 33, then more charging switches 31 need to be set.

[0068] In some embodiments of the present application, the discharge switch 32 is disposed on the first side 33a of the DC-DC converter 33, and the charging switch 31 is disposed on the second side 33b of the DC-DC converter 33, and the number of the discharge switches 32 does not need to be consistent with the number of the charging switches 31. In the embodiment of the present application, M is less than N, and the design cost is saved by reducing the number of the charging switches 31.

[0069] For some examples, see Figure 5 The battery management device 300 includes a current sensor 37 , which is disposed on the main circuit, and the integrated circuit 34 is electrically connected to the current sensor 37 .

[0070] The current sensor 37 is disposed on the first side 33 a of the DC-DC converter 33 . The current sensor 37 is used to collect the current on the main circuit 30 a , for example, the discharge current and the charge current.

[0071] When the battery pack 100 is discharging, the integrated circuit 34 detects that the discharge current on the main circuit 30a is greater than the discharge current threshold, for example, the discharge current threshold is the maximum discharge current of the battery pack, and the integrated circuit controls the discharge switch 32 to stop working and cut off the main circuit to prevent excessive discharge current from impacting the switching devices on the secondary battery module 200 and the battery management device 300.

[0072] When the charging device charges the battery pack 100, the integrated circuit 34 monitors that the charging current on the main circuit 30a is greater than the charging current threshold, for example, the charging current threshold is the maximum charging current of the battery pack, and the integrated circuit controls the charging switch 31 to stop working and cut off the main circuit to prevent excessive charging current from impacting the switching devices on the cascade battery module 200 and the battery management device 300.

[0073] In some embodiments of the present application, the current sensor 37 is a current sampling resistor or a Hall sensor.

[0074] See also Figure 6 The battery management device 300 includes a current detection circuit 38 , which is disposed on the main circuit and electrically connected to the integrated circuit 34 .

[0075] The current detection circuit 38 is disposed on the second side 33b of the DC-DC converter 33. When the battery pack 100 is discharging, the current detection circuit 38 is used to detect the current flowing through the load. When the integrated circuit 34 detects that the current is greater than a discharge current threshold, for example, the discharge current threshold is the maximum discharge current of the battery pack, the integrated circuit controls the discharge switch 32 to stop working and cut off the main circuit to prevent excessive discharge current from impacting the switch devices on the secondary battery module 200 and the battery management device 300.

[0076] In some operating conditions, a short circuit occurs on the load side, that is, a short circuit occurs between the positive output terminal P+ and the negative output terminal P- of the battery pack. The current detection circuit 38 detects that the current flowing through the load is too large, for example, exceeding the maximum discharge current of the battery pack. The integrated circuit 34 controls the discharge switch 32 to turn off, cutting off the main circuit 30a, thereby avoiding the impact of the large current caused by the short circuit on the discharge switch 32 and the cascade battery module 200.

[0077] See also Figure 7 The current detection circuit 38 includes a shunt 381, an amplifier 382 and a comparator 383. The shunt 381 is arranged on the main circuit, the amplifier 382 is electrically connected to the shunt 381, the amplifier 382 is electrically connected to the comparator 383, and the comparator 383 is electrically connected to the integrated circuit 34.

[0078] The shunt 381 is used to collect the current flowing through the load, the amplifier 382 amplifies the current, and the comparator 383 compares the amplified current with the preset current threshold to obtain the current detection result. The integrated circuit 34 controls the working state of the discharge switch 32 based on the current detection result, and / or controls the working state of the charging switch 31 and the DC-DC converter.

[0079] When the current flowing through the load is greater than the discharge current threshold, the output terminal of the comparator outputs a high level, and the I / O pin of the integrated circuit 34 receives the high level, further controlling the discharge switch 32 to turn off, and / or further controlling the charging switch 31 and the DC-DC converter 33 to stop working.

[0080] In the embodiment of the present application, a current sensor 37 is set on one side of the positive electrode B+ of the cascade battery cell module 200 to monitor the overcurrent condition of the cascade battery cell module 200 in the charging and discharging state, and a current detection circuit 38 is set on one side of the positive output terminal P+ to monitor the overcurrent condition on the load side (for example, a short circuit occurs on the load side) so as to protect the cascade battery cell module 200 in time.

[0081] Typically, the DC-DC converter 33 includes an inductor, which has a hysteresis effect on the current. When a short circuit occurs on the load side and a large current appears, the current detection circuit 38 relative to the current sensor 37 can quickly and timely collect the large current on the load side so that the integrated circuit 34 can perform the short circuit protection operation in a timely and rapid manner.

[0082] See also Figure 8 The integrated circuit 34 includes an analog front end chip (Ana l og Front End, AFE) 341 and a micro control unit 342, and the analog front end chip 341 communicates and interacts with the micro control unit 342.

[0083] In some embodiments, Figure 8 As shown, the current sensor 37 and the current detection circuit 38 are both electrically connected to the analog front-end chip 341 .

[0084] The analog front-end chip 341 processes and analyzes the real-time current collected by the current sensor 37. When the real-time current is greater than the charging current threshold or the discharging current threshold, the charging switch 31 and / or the discharging switch 32 are controlled to stop working.

[0085] The analog front-end chip 341 controls the working state of the discharge switch 32 in response to the current detection result output by the current detection circuit 38. Specifically, when the current detection circuit 38 detects that the current flowing through the load is greater than the discharge current threshold, the analog front-end chip 341 controls the discharge switch 32 to be turned off.

[0086] In other embodiments, see Fig. 9 The current sensor 37 and the current detection circuit 38 are both electrically connected to the micro control unit 342 .

[0087] The micro control unit 342 processes and analyzes the real-time current collected by the current sensor 37. When the real-time current is greater than the charging current threshold or the discharging current threshold, the DC-DC converter 33 is controlled to stop working. Alternatively, the micro control unit 342 communicates with the analog front-end chip 341 to notify the analog front-end chip 341 to control the charging switch 31 and / or the discharging switch 32 to stop working.

[0088] The micro control unit 342 controls the working state of the DC-DC converter 33 in response to the current detection result output by the current detection circuit 38. Specifically, when the current detection circuit 38 detects that the current flowing through the load is greater than the discharge current threshold, the micro control unit 342 controls the DC-DC converter to shut down, or the micro control unit 342 communicates with the analog front-end chip 341 to notify the analog front-end chip 341 to control the charging switch 31 and / or the discharging switch 32 to stop working.

[0089] In other embodiments, see Fig.10The current sensor 37 is electrically connected to the analog front-end chip 341 , and the current detection circuit 38 is electrically connected to the micro control unit 342 .

[0090] The analog front-end chip 341 processes and analyzes the real-time current collected by the current sensor 37. When the real-time current is greater than the charging current threshold or the discharging current threshold, the charging switch 31 and / or the discharging switch 32 are controlled to stop working.

[0091] The micro control unit 342 controls the working state of the charging DC-DC converter 33 in response to the current detection result output by the current detection circuit 38. Specifically, when the current detection circuit 38 detects that the current flowing through the load is greater than the discharge current threshold, the micro control unit 342 controls the DC-DC converter to shut down, or the micro control unit 342 communicates with the analog front-end chip 341 to notify the analog front-end chip 341 to control the charging switch 31 and / or the discharging switch 32 to stop working.

[0092] The embodiment of the present application assigns the task of detecting the charging and discharging current of the cascade battery module 200 to the analog front-end chip 341, and assigns the task of detecting the load current to the microcontroller unit 342, thereby improving the timeliness of detecting excessive short-circuit current.

[0093] See also Fig.11 The first preamplifier circuit 35 includes a first preamplifier switch 351, a first resistor 352 and a boost circuit 353. The first preamplifier switch 351, the first resistor 352 and the boost circuit 353 are connected in series, and the integrated circuit 34 is electrically connected to the first preamplifier switch 351 and the boost circuit 353 respectively.

[0094] The first preamp switch 351 is controlled by the integrated circuit 34. When the integrated circuit 34 applies a first level signal to the first preamp switch 352, the first preamp switch 351 enters an on state. When the integrated circuit 34 applies a second level signal to the first preamp switch 352, the first preamp switch 351 enters an off state. For example, the first level signal is a high level and the second level signal is a low level; or, the first level signal is a low level and the second level signal is a high level.

[0095] The first resistor 352 is used to limit the current provided by the first preamplifier circuit 35 to the load.

[0096] The boost circuit 353 is used to boost the voltage of the secondary battery module 200. For example, the voltage of the secondary battery module 200 is 40V, and the voltage requirement range of the load is 40-58V. The boost circuit boosts 40V to 40-58V, for example, to 58V, and then outputs it to the load.

[0097] See also Fig.12The DC-DC converter 33 includes an energy storage unit 39 and a DC-DC conversion unit 40 . The energy storage unit 39 includes a first capacitor 391 and a second capacitor 392 .

[0098] The first capacitor 391 is disposed between the DC-DC conversion unit 40 and the discharge switch 32 . A first end of the first capacitor 391 is electrically connected to the main circuit 30 a , and a second end of the first capacitor 391 is electrically connected to the ground.

[0099] The second capacitor 392 is provided between the DC-DC conversion unit 40 and the charging switch 31, the first end of the second capacitor 392 is electrically connected to the main circuit 30a, the second end of the second capacitor 392 is electrically connected to the ground, and the DC-DC conversion unit 40 is electrically connected between the main circuit and the ground.

[0100] Before controlling the charging switch 31 and the discharging switch 32 to close, the integrated circuit 34 first controls the second pre-discharge circuit 36 ​​to enter the working state. The current provided by the cascade battery module 200 charges the first capacitor 391 and the second capacitor 392 through the second pre-discharge circuit 36, avoiding directly closing the charging switch 31 and the discharging switch 32, and generating an excessive discharge current to impact the charging switch 31, the discharging switch 32 and the cascade battery module 200.

[0101] See also Fig.13 The second preamplifier circuit 36 ​​includes a second preamplifier switch 361 and a second resistor 362 , the second preamplifier switch 361 and the second resistor 362 are connected in series, and the integrated circuit 34 is electrically connected to the second preamplifier switch 361 .

[0102] The second preamp switch 361 is controlled by the integrated circuit 34. When the integrated circuit 34 applies the third level signal to the second preamp switch 361, the second preamp switch 361 enters the on state. When the integrated circuit 34 applies the fourth level signal to the second preamp switch 361, the second preamp switch 361 enters the off state. For example, the third level signal is a high level, and the fourth level signal is a low level; or, the third level signal is a low level, and the fourth level signal is a high level.

[0103] The second resistor 352 is used to limit the current output by the second preamplifier circuit 35 .

[0104] Before controlling the DC-DC converter 33 to enter the working state, the integrated circuit 34 controls the second pre-discharge switch 361 to enter the conducting state, and the current provided by the cascade battery module 200 charges the first capacitor 391 and the second capacitor 392 through the second pre-discharge switch 361 .

[0105] Since the voltage across the first capacitor 391 and the second capacitor 392 has been pre-charged to be equal to or close to the voltage of the ladder cell module 200 during the pre-charging stage, when the integrated circuit 34 controls the DC-DC converter 33 to enter the working state, the instantaneous charging current provided by the ladder cell module 200 to the first capacitor 391 and the second capacitor 392 is smaller than the instantaneous charging current provided to the first capacitor 391 and the second capacitor 392 without the pre-charging process, thereby avoiding the occurrence of a large current caused by the first capacitor 391 and the second capacitor 392 being short-circuited in an instant due to the lack of stored energy.

[0106] It can be understood that the first pre-amp switch 351 and the second pre-amp switch 361 are electronic switch tubes or relays, and the electronic switch tubes include triodes, metal-oxide-semiconductor field effect transistors, insulated gate bipolar transistors, etc.

[0107] In some embodiments, please refer to Fig.13 The micro control unit 342 is electrically connected to the first pre-amp switch 351 and the second pre-amp switch 352. The analog front-end chip 341 is electrically connected to the charging switch 31 and the discharging switch 32.

[0108] In some other embodiments, see Fig.14 The analog front-end chip 341 is electrically connected to the charging switch 31 and the discharging switch 32 respectively, and the microcontroller unit 342 is electrically connected to the first preamplifier switch 351, the second preamplifier switch 361, the charging switch 31 and the discharging switch 32 respectively, that is: the microcontroller unit 342 and the analog front-end chip 341 jointly control the discharging switch 32 and the charging switch 31, and the microcontroller unit 342 controls the first preamplifier switch 351 and the second preamplifier switch 361 respectively.

[0109] Please continue reading Fig.14 The battery management device 300 includes a first AND gate 310 and a second AND gate 311. The two input ends of the first AND gate 310 are electrically connected to the analog front-end chip 341 and the micro control unit 342, respectively, and the output end of the first AND gate 310 is electrically connected to the discharge switch 32. The two input ends of the second AND gate 311 are electrically connected to the analog front-end chip 341 and the micro control unit 342, respectively, and the output end of the second AND gate 311 is electrically connected to the charging switch 31.

[0110] The first AND gate 310 controls the state of the discharge switch 32 in response to the first control signal of the analog front-end chip 341 and the second control signal of the micro control unit 342 .

[0111] The analog front-end chip 341 communicates with the micro control unit 342 to determine the working state of the battery management device 300. When the battery management device 300 enters the discharge state, the analog front-end chip 341 outputs a first control signal, and the micro control unit 342 outputs a second control signal. Both the first control signal and the second control signal are high level. Under the action of the first control signal and the second control signal, the first AND gate 310 outputs a high level, and the discharge switch 32 responds to the high level input and enters the conduction state.

[0112] When the battery management device 300 does not need or cannot enter the discharge state, the analog front-end chip 341 outputs a low level, or the micro control unit 342 outputs a low level. The first AND gate 310 outputs a low level under the action of a low level and a high level, or under the action of two low levels. The discharge switch 32 responds to the low level input and enters the disconnected state.

[0113] Similarly, the second AND gate 311 controls the state of the charging switch 31 in response to the third control signal of the analog front-end chip 341 and the fourth control signal of the micro control unit 342 .

[0114] When the battery management device 300 enters the charging state, the analog front-end chip 341 outputs the third control signal, and the micro control unit 342 outputs the fourth control signal. The third control signal and the fourth control signal are both high level. Under the action of the third control signal and the fourth control signal, the second AND gate 311 outputs a high level, and the charging switch 31 responds to the high level input and enters the conducting state.

[0115] When the battery management device 300 does not need or cannot enter the charging state, the analog front-end chip 341 outputs a low level, or the micro control unit 342 outputs a low level. The second AND gate 311 outputs a low level under the action of a low level and a high level, or under the action of two low levels. The charging switch 31 responds to the low level input and enters the disconnected state.

[0116] In the embodiment of the present application, based on the first AND gate and the second AND gate, the analysis result of the analog front-end chip 341 and the analysis result of the micro control unit 342 are comprehensively processed, so as to more reliably control the states of the charging switch 31 and the discharging switch 32 .

[0117] See also Fig.15 The battery management device 300 includes a temperature sampling circuit 312, which is electrically connected to the micro control unit 342 and is used to collect the operating temperature of the battery management device 300. The micro control unit 342 generates a prompt message in response to the operating temperature being greater than a preset temperature threshold.

[0118] As mentioned above, the DC-DC converter 33 is a boost-buck circuit. In some embodiments, the DC-DC converter 33 is a single-phase boost-buck circuit. In some embodiments, the DC-DC converter 33 is a multi-phase interleaved parallel boost-buck circuit.

[0119] The DC-DC converter 33 includes α DC-DC conversion units, the α DC-DC conversion units are connected in parallel, the difference between any two adjacent phases in the α DC-DC conversion units is β, and the sum of the phases of the α DC-DC conversion units is 360 degrees, that is, α*β=360, α and β are both positive integers. Exemplarily, α is 4, and β is 90 degrees.

[0120] See also Fig.16 , the four DC-DC conversion units are respectively the first DC-DC conversion unit 331, the second DC-DC conversion unit 332, the third DC-DC conversion unit 333 and the fourth DC-DC conversion unit 334. For the same switch of the above four DC-DC conversion units, the switch of the first DC-DC conversion unit 331 is turned on at the first moment, and after a phase interval of 90 degrees, the switch of the second conversion unit 332 is turned on, after a phase interval of 90 degrees, the switch of the third conversion unit 333 is turned on, and after a phase interval of 90 degrees, the switch of the fourth conversion unit 334 is turned on. The embodiment of the present application adopts a multi-phase interleaved parallel boost-buck circuit, which can disperse the load current, reduce the current stress of each DC-DC conversion unit, and effectively improve the power conversion efficiency.

[0121] Understandably, see Fig.17 Each DC-DC conversion unit includes an inductor, a first switch and a second switch. The same switch for the four DC-DC conversion units is the first switch for each DC-DC conversion unit, or the second switch for each DC-DC conversion unit.

[0122] The DC-DC conversion unit includes an inductor, a first switch and a second switch. The inductor and the first switch are connected in series to the main circuit. The second switch is electrically connected between the inductor and the first switch and in parallel with the first switch. Both the first switch and the second switch are electrically connected to the micro control unit 342.

[0123] Please also read Fig.18 and Fig.19 When the battery management device 300 is in a discharging state, the micro control unit 342 controls the first switch and the second switch tube according to the discharge switch timing of the first switch and the discharge switch timing of the second switch, respectively, so that the DC-DC conversion unit boosts the voltage of the cascade battery module 200 to provide it to the load.

[0124] Similarly, when the battery management device 300 is in a charging state, the micro control unit 342 controls the first switch and the second switch tube according to the charging switch timing of the first switch and the charging switch timing of the second switch respectively, so that the DC-DC conversion unit steps down the voltage provided by the charging device so as to provide it to the cascade battery cell module 200.

[0125] The inductor provided in the embodiment of the present application adopts an EI E type magnetic integrated inductor, which is composed of two E-type magnetic cores and one I-type magnetic core. The magnetic flux paths of the two E-type magnetic cores are coupled to each other through the I-type magnetic core. Such coupling helps to reduce magnetic flux leakage and electromagnetic interference, improve magnetic flux utilization, thereby reducing losses and improving energy transfer efficiency.

[0126] See also Fig. 20 The battery management device 300 further includes a wake-up circuit 41 , which is electrically connected to the first pre-discharge circuit 35 and the integrated circuit 34 .

[0127] When the wake-up circuit 41 detects that the current applied to the load by the ladder cell module 200 is less than the current wake-up threshold, it sends a first trigger level to the integrated circuit 34, and the first trigger level is used to indicate that the load is in a sleep state.

[0128] When the wake-up circuit 41 detects that the current applied to the load by the ladder battery module 200 is greater than the current wake-up threshold, it sends a second trigger level to the integrated circuit 34 to enable the integrated circuit to enter a normal working state. The first trigger level is opposite to the second trigger level. When the first trigger level is high, the second trigger level is low, and when the first trigger level is low, the second trigger level is high.

[0129] See also Fig.21 The wake-up circuit 41 includes a third resistor 411, a fourth resistor 412, a PNP transistor 413, a fifth resistor 414, a sixth resistor 415, a seventh resistor 416 and a first N-type MOS transistor 417. The third resistor 411 is connected in series with the fourth resistor 412 and then connected in parallel with the first resistor 352. The emitter of the PNP transistor 413 is electrically connected to one end of the third resistor 411, the base of the PNP transistor 413 is electrically connected to the other end of the third resistor 411, the collector of the PNP transistor 413 is electrically connected to one end of the fifth resistor 414, the other end of the fifth resistor 414 and one end of the sixth resistor 415 are both electrically connected to the gate of the first N-type MOS transistor 417, the other end of the sixth resistor 415 is grounded, the source of the first N-type MOS transistor 417 is electrically connected to one end of the seventh resistor 416 and the micro control unit 342 respectively, the other end of the seventh resistor 416 is applied with the system power supply VCC, and the drain of the first N-type MOS transistor 417 is grounded.

[0130] When the load is in a sleep state, the current applied to the load by the ladder cell module 200 is relatively small, and the voltage drop between the emitter and the base of the PNP transistor 413 meets the conduction condition. Therefore, the PNP transistor 413 enters the conduction state, and the voltage of the gate of the first N-type MOS transistor 417 is raised, so that the first N-type MOS transistor 417 enters the conduction state, and the micro control unit 342 receives the first trigger level as a low level.

[0131] When the load is in normal working state, the current applied to the load by the ladder cell module 200 is relatively large, and the voltage drop between the emitter and the base of the PNP transistor 413 does not meet the conduction condition. Therefore, the PNP transistor 413 enters the off state, and the voltage of the gate of the first N-type MOS transistor 417 is pulled down, so that the first N-type MOS transistor 417 enters the off state, and the micro control unit 342 receives the second trigger level as a high level. The micro control unit 342 responds to the second trigger level and enters the normal working state.

[0132] In order to explain the working principle of the battery management device provided in the embodiment of the present application in detail, the embodiment of the present application is described in detail with reference to the following examples, which are as follows:

[0133] like Fig.17 As shown, the load 160 is electrically connected between the positive output terminal P+ and the negative output terminal P-. The first pre-discharge switch 351 is set to the on state by default. When the load 160 enters the dormant state, the current provided by the ladder battery module 200 is transmitted to the load 160 through the first pre-discharge switch 351, the first resistor 352 and the boost circuit 353 to maintain the power required by the load 160 in the dormant state.

[0134] The first DC-DC conversion unit 331 of the DC-DC converter 33 includes an inductor L1-1, a first switch H01 and a second switch L01, the second DC-DC conversion unit 332 includes an inductor L1-2, a first switch H02 and a second switch L02, the third DC-DC conversion unit 333 includes an inductor L1-3, a first switch H03 and a second switch L03, and the fourth DC-DC conversion unit 334 includes an inductor L1-4, a first switch H04 and a second switch L04.

[0135] When the battery management device 300 is in a discharging state:

[0136] When the load 160 enters a normal working state, the wake-up circuit 41 detects that the current applied to the load 160 from the positive output terminal P+ is greater than the current wake-up threshold, and the wake-up circuit 41 sends a high level to the micro control unit 342. The micro control unit 342 is triggered by the high level and enters a normal working state.

[0137] Under normal working conditions, the microcontroller unit 342 first controls the second pre-release switch 361 to enter the on state, and the current provided by the ladder battery module 200 charges the first capacitor 391 and the second capacitor 392 respectively. When the voltage across the first capacitor 391 and the second capacitor 392 is equal to or close to the voltage of the ladder battery module 200, the microcontroller unit 342 turns off the second pre-release switch 361, communicates with the analog front-end chip 341, and controls the charging switch 31 and the discharging switch 32 to close.

[0138] Specifically, under the joint action of the analog front-end chip 341 and the micro control unit 342, the first AND gate 310 sends a high level DSG_EN to the discharge switch 32, and under the joint action of the analog front-end chip 341 and the micro control unit 342, the second AND gate 311 sends a high level to the charging switch 31, and the discharge switch 32 enters the on state, and the charging switch 31 enters the on state.

[0139] The microcontroller unit 342 performs a voltage boost operation according to the DC-DC converter 33, wherein the switching timing of the second switch and the first switch of each DC-DC conversion unit in the DC-DC converter 33 is referred to as Fig.18 and Fig.19 The actions are performed and will not be described in detail here.

[0140] The charging device is electrically connected between the positive output terminal P+ and the negative output terminal P-.

[0141] When the battery management device 300 is in a charging state:

[0142] The micro control unit 342 controls the second pre-release switch 361 to enter the on state, and the current provided by the ladder battery module 200 charges the first capacitor 391 and the second capacitor 392 respectively. When the voltage across the first capacitor 391 and the second capacitor 392 is equal to or close to the voltage of the ladder battery module 200, the micro control unit 342 turns off the second pre-release switch 361, communicates with the analog front-end chip 341, and controls the charging switch 31 and the discharging switch 32 to close.

[0143] Under the joint action of the analog front-end chip 341 and the micro control unit 342, the first AND gate 310 sends a high level to the discharge switch 32, and under the joint action of the analog front-end chip 341 and the micro control unit 342, the second AND gate 311 sends a high level CHG_EN to the charging switch 31, and the discharge switch 32 enters the on state, and the charging switch 31 enters the on state.

[0144] The micro control unit 342 performs a step-down operation according to the DC-DC converter 33, wherein the switching timing of the second switch and the first switch of each DC-DC conversion unit in the DC-DC converter 33 is the same as that of the first switch. Fig.18 and Fig.19The principle of the switching timing is the same and will not be repeated here.

[0145] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A battery management device, comprising: A charging switch, a discharging switch and a DC-DC converter are arranged on the main circuit, wherein the charging switch, the discharging switch and the DC-DC converter are connected in series; An integrated circuit is electrically connected to the charging switch, the discharging switch and the DC-DC converter respectively, and is configured to control the charging switch, the discharging switch and the DC-DC converter; characterized in that the battery management device also includes: A first pre-discharge circuit is configured to have one end electrically connected to the positive electrode of the battery module and the other end electrically connected to the positive output terminal, the first pre-discharge circuit being connected in parallel with the first path where the charging switch, the discharging switch and the DC-DC converter are located; A second pre-discharge circuit is connected in parallel with the discharge switch; The integrated circuit is electrically connected to the first preamplifier circuit and the second preamplifier circuit respectively.

2. The battery management device according to claim 1, characterized in that: The first path is provided between the positive electrode of the battery module and the positive output terminal; The discharge switch is disposed on a first side of the DC-DC converter, and the charge switch is disposed on a second side of the DC-DC converter; The first side of the DC-DC converter is configured to be closer to the positive electrode of the battery module than the second side of the DC-DC converter.

3. The battery management device according to claim 2, characterized in that: The number of the discharge switches is N, and the N discharge switches are connected in parallel; The number of the charging switches is M, and the M charging switches are connected in parallel; Wherein, M is less than N, and both M and N are positive integers.

4. The battery management device according to any one of claims 1 to 3, characterized in that: Also includes: A current sensor and a current detection circuit provided on the main circuit, wherein the current sensor and the current detection circuit are both electrically connected to the integrated circuit; The current sensor is arranged on a first side of the DC-DC converter, and the current detection circuit is arranged on a second side of the DC-DC converter; The first side of the DC-DC converter is configured to be closer to the positive electrode of the battery module than the second side of the DC-DC converter.

5. The battery management device according to claim 4, characterized in that: The integrated circuit includes an analog front-end chip and a micro control unit; The current sensor and the current detection circuit are both electrically connected to the analog front-end chip; or, The current sensor and the current detection circuit are both electrically connected to the micro control unit; or, The current sensor is electrically connected to the analog front-end chip, and the current detection circuit is electrically connected to the micro control unit.

6. The battery management device according to any one of claims 1 to 5, characterized in that: The first preamplifier circuit comprises: a first preamplifier switch, a first resistor and a boost circuit, the first preamplifier switch, the first resistor and the boost circuit are connected in series, and the integrated circuit is electrically connected to the first preamplifier switch and the boost circuit respectively; The second preamplifier circuit includes: a second preamplifier switch and a second resistor, the second preamplifier switch and the second resistor are connected in series, and the integrated circuit is electrically connected to the second preamplifier switch.

7. The battery management device according to claim 6, characterized in that: The integrated circuit includes an analog front-end chip and a micro control unit; The analog front-end chip is electrically connected to the charging switch and the discharging switch respectively; The micro control unit is electrically connected to the first pre-release switch and the second pre-release switch respectively; or, The analog front-end chip is electrically connected to the charging switch and the discharging switch respectively; The micro control unit is electrically connected to the first pre-discharge switch, the second pre-discharge switch, the charging switch and the discharging switch respectively.

8. The battery management device according to any one of claims 1 to 7, characterized in that: The integrated circuit includes a micro control unit, and the micro control unit is electrically connected to the DC-DC converter; The DC-DC converter includes an energy storage unit and a DC-DC conversion unit, and the energy storage unit includes: A first capacitor is provided between the DC-DC conversion unit and the discharge switch, a first end of the first capacitor is electrically connected to the main circuit, and a second end of the first capacitor is electrically connected to a ground end; A second capacitor is provided between the DC-DC conversion unit and the charging switch, a first end of the second capacitor is electrically connected to the main circuit, and a second end of the second capacitor is electrically connected to the ground; The DC-DC conversion unit is electrically connected between the main circuit and the ground terminal.

9. The battery management device according to any one of claims 1 to 8, characterized in that: The DC-DC converter includes a single-phase step-up / step-down circuit or a multi-phase interleaved parallel step-up / step-down circuit.

10. The battery management device according to any one of claims 1 to 9, characterized in that: It also includes a wake-up circuit, which is electrically connected to the first preamplifier circuit and the integrated circuit respectively.

11. A battery pack, comprising a secondary battery cell module and a battery management device as claimed in any one of claims 1 to 9; The cascade battery cell module includes a plurality of battery cells, and a full charge capacity of at least one battery cell among the plurality of battery cells is less than a rated capacity.

12. An electrical device, characterized in that The invention comprises a load and the battery pack as claimed in claim 10.

Images