Battery pack suitable for electric vehicle

Abstract

The utility model relates to the technical field of battery packs, and discloses a battery pack suitable for an electric vehicle, which comprises a main battery pack and a sub-battery pack connected with the main battery pack in series, the first three-terminal fuse is connected with the first battery pack; the first control unit is connected with the control end of the first three-end fuse; a sub-battery pack including: a second battery pack; the MOS circuit is connected with the first battery pack and the second battery pack, and the MOS circuit is used for controlling the on-off of a charging and discharging loop after the main battery pack and the sub battery packs are connected in series; and the second control unit is connected with the control ends of the plurality of MOS tubes in the MOS circuit. According to the utility model, after the main battery pack and the sub battery packs are connected in series, the MOS circuit is positioned in the middle of the battery pack in the charging and discharging processes, so that the use cost of half of the MOS circuit is reduced, that is, the use cost of a plurality of MOS tubes, resistors and other components in the MOS circuit is reduced, and the production cost of the battery pack is further greatly reduced.

Description

Technical Field

[0001] This utility model relates to the field of battery pack technology, and specifically to a battery pack suitable for electric vehicles. Background Technology

[0002] The battery pack is a core component of electric two-wheelers and electric tricycles. It consists of multiple battery cells. Electric two-wheelers and electric tricycles are collectively referred to as electric vehicles, and the battery pack is the power source for these vehicles. There are many types of battery packs, among which lead-acid batteries have the longest history. Currently, sodium-ion batteries are gradually replacing lead-acid batteries. Because the size of sodium-ion batteries must be compatible with the size of the electric vehicle's battery compartment, battery packs with nominal voltages of 48V, 60V, and 72V typically require two battery packs connected in series. Therefore, during battery pack production, two types of battery packs need to be manufactured for each nominal voltage. Simultaneously, each battery pack requires a Battery Management System (BMS) protection board; that is, a battery pack suitable for an electric vehicle requires two BMS protection boards. As the demand for electric vehicles increases, the production demand for battery packs also increases accordingly. Therefore, how to reduce the design cost of battery packs is an urgent issue that needs attention.

[0003] In related technologies, MOS circuits are usually installed in two battery packs connected in series. If battery packs are mass-produced and MOS circuits are installed in each battery pack, the production cost of the battery packs will be relatively high. Utility Model Content

[0004] In view of this, the present invention provides a battery pack suitable for electric vehicles to solve the problem of high production costs of battery packs in related technologies.

[0005] In a first aspect, this utility model provides a battery pack suitable for electric vehicles, comprising: a main battery pack and a sub-battery pack connected in series with the main battery pack, wherein the main battery pack includes:

[0006] First battery pack;

[0007] The first three-terminal fuse is connected to the first battery pack;

[0008] The first control unit is connected to the control terminal of the first three-terminal fuse;

[0009] Sub-battery pack, including:

[0010] Second battery pack;

[0011] The MOS circuit is connected to the first and second battery packs. The MOS circuit is used to control the on / off state of the charging and discharging circuit after the main battery pack and the sub-battery pack are connected in series.

[0012] The second control unit is connected to the control terminals of multiple MOS transistors in the MOS circuit.

[0013] In this embodiment, the MOS circuit is located in the sub-battery pack, and the main battery pack does not contain the MOS circuit. If the battery pack is mass-produced, half of the MOS circuit is saved, thereby reducing the production cost of the battery pack.

[0014] In some specific embodiments, the battery pack of this invention suitable for electric vehicles has multiple MOS transistors in the MOS circuit located in the middle of the series connection between the main battery pack and the sub-battery pack. The MOS circuit includes:

[0015] The main control circuit is connected between the first battery pack and the second battery pack.

[0016] The first MOSFET has its source terminal connected to the main control circuit and its control terminal connected to the second control unit.

[0017] The drain of the second MOSFET is connected to the drain of the first MOSFET through a bypass resistor, its control terminal is connected to the second control unit, and its source terminal is connected to the main control circuit.

[0018] In this embodiment, after the main battery pack and the sub-battery pack are connected in series, the MOS circuit is located in the middle of the battery pack during its charging and discharging process, which reduces the cost of using the MOS circuit by half. That is, it reduces the cost of using multiple MOS transistors and resistors in the MOS circuit, thereby greatly reducing the production cost of the battery pack.

[0019] In some specific embodiments, the battery pack and sub-battery pack of this invention for electric vehicles further include:

[0020] The LDO chip is connected to the MOS circuit and the external power supply. It is used to turn on the output voltage of the external power supply, control the first MOS transistor to turn on, and then charge the first and second battery packs through the external power supply.

[0021] Bypass resistor, used to assist in turning on the first MOSFET;

[0022] An optocoupler, connected to a second control unit, is used to obtain an optocoupler signal through the second control unit when the charging power obtained by the first battery pack and the second battery pack meets the requirements. This signal controls the output terminal of the LDO chip to connect to the source terminal of the first MOS transistor, making the gate-source voltage of the first MOS transistor in the MOS circuit zero. The first MOS transistor in the MOS circuit is then disconnected, and charging is performed through the main control loop.

[0023] This embodiment, through the aforementioned LDO chip, bypass resistor, and optocoupler, can not only achieve normal charging of the first and second battery packs, but also achieve 0V charging of the first and second battery packs when the external power supply is disconnected.

[0024] In some specific embodiments, the battery pack of this utility model applicable to electric vehicles further includes a second three-terminal fuse, the control terminal of which is connected to a second control unit.

[0025] In this embodiment, the second three-terminal fuse is used as a three-terminal fuse for safety certification, serving as a one-time safety protection switch for abnormal operating conditions, thereby protecting the safety of the second battery pack.

[0026] In some specific embodiments, the battery pack of this utility model applicable to electric vehicles is provided with a communication line and a charging line between the main battery pack and the sub-battery pack, wherein the communication line is used to establish a communication connection between the first control unit and the second control unit.

[0027] In this embodiment, communication between the main battery pack and the sub-battery pack is achieved through a communication line, and charging and discharging between the main battery and the sub-battery are achieved through a charging line.

[0028] In some specific embodiments, the battery pack of this utility model for electric vehicles, the main battery pack, further includes:

[0029] The power absorption circuit is connected to the first three-terminal fuse and the charging line, and is used to absorb the power of the charging line when a load to be charged is connected between the main battery pack and the sub-battery pack.

[0030] In this embodiment, when the battery pack supplies power to the outside, the external inductive load to be charged will generate a reverse electromotive force. Through the energy absorption circuit, the reverse electromotive force is absorbed and dissipated, thus avoiding damage to the core components of the battery pack.

[0031] In some specific embodiments, the main battery pack of the present invention for electric vehicles further includes:

[0032] The communication chip connects to the first control unit and the user terminal to transmit operating status information of the main battery pack and sub-battery pack to the user.

[0033] This embodiment enables wireless connection with the user's mobile terminal via a communication chip, allowing the user to query the battery pack's operating status information.

[0034] In some specific embodiments, the battery pack of this utility model applicable to electric vehicles has the following battery packs: the first battery pack has 13 or 8 battery strings, and the second battery pack has 13, 12, 9, or 8 battery strings.

[0035] This embodiment determines the number of battery strings in the first and second battery packs to facilitate battery combination according to nominal 48V, nominal 60V, and nominal 72V battery packs.

[0036] In some specific embodiments, the battery pack of this utility model applicable to electric vehicles has a first battery pack with a first nominal voltage and a second nominal voltage sharing 13 strings, and a second battery pack with a third nominal voltage sharing 9 or 8 strings.

[0037] In this embodiment, the first nominal voltage and the second nominal voltage share a first battery pack with 13 strings, and the third nominal voltage and the first nominal voltage share a second battery pack with 9 strings or 8 strings. By combining the two in pairs, three battery pack specifications can be obtained. Therefore, the number of production lines is greatly reduced in production, thereby reducing production and maintenance costs.

[0038] In some specific embodiments, the main battery pack of the present invention for electric vehicles further includes:

[0039] The first analog front-end circuit is connected to the first battery pack and is used to sample key parameters of the first battery pack.

[0040] The sub-battery pack also includes:

[0041] The second analog front-end circuit is connected to the second battery pack and is used to sample key parameters of the second battery pack.

[0042] In this embodiment, the first analog front-end circuit facilitates the collection of key data such as cell voltage and temperature of the first battery pack, and the second analog front-end circuit facilitates the collection of key data such as cell voltage and temperature of the second battery pack. Attached Figure Description

[0043] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a first circuit diagram of a battery pack for electric vehicles according to an embodiment of the present invention;

[0045] Figure 2 This is a second circuit diagram of a battery pack for electric vehicles according to an embodiment of the present invention;

[0046] Figure 3This is a third circuit diagram of a battery pack for electric vehicles according to an embodiment of the present invention.

[0047] Figure label:

[0048] 11-Main battery pack; 12-Sub-battery pack; 13-Communication line; 14-Charging line;

[0049] 111-First battery pack; 112-First three-terminal fuse; 113-First control unit;

[0050] 114 - Power absorption circuit; 115 - Communication chip; 116 - First analog front-end circuit;

[0051] 121 - Second battery pack; 122 - MOS circuit; 123 - Second control unit;

[0052] 1221 - Main control circuit; 1222 - First MOSFET; 1223 - Second MOSFET;

[0053] 124 - LOD chip; 125 - Bypass resistor; 126 - Optocoupler;

[0054] 127 - Second three-terminal fuse; 128 - Second analog front-end circuit. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0056] According to an embodiment of the present invention, a battery pack suitable for electric vehicles is provided, such as... Figure 1 As shown, there is a main battery pack 11 and a sub-battery pack 12 connected in series with the main battery pack. The main battery pack 11 includes: a first battery group 111, a first three-terminal fuse 112, and a first control unit 113. The sub-battery pack 12 includes: a second battery group 121, a MOS circuit 122, and a second control unit 123.

[0057] The main battery pack and sub-battery packs typically integrate battery cells, a battery management system (BMS), a thermal management system, structural components, and electrical components. The main battery pack is usually responsible for overall control, while the sub-battery packs, as subordinate units of the main battery pack, perform scheduling tasks through the main battery pack and generally do not have independent management capabilities.

[0058] Among them, Figure 1 In the main battery pack 11, there are: a first battery 111, a first three-terminal fuse 112, and a first control unit 113. The sub-battery pack 12 includes: a second battery pack 121, a MOS circuit 122, and a second control unit 123.

[0059] In a specific example, the number of battery strings in the first battery pack may be 13 or 8; the number of battery strings in the second battery pack may be 13, 12, 9 or 8.

[0060] exist Figure 1 In the diagram, the first battery pack is designated BT-L, with the anode terminal of the first battery pack 111 being terminal 1 and the cathode terminal of the first battery pack 111 being terminal 2. The second battery pack 121 is designated BT-H, with the anode terminal of the second battery pack 121 being terminal 1 and the cathode terminal of the second battery pack 121 being terminal 2.

[0061] In another specific example, the first nominal voltage and the second nominal voltage share a first battery pack of 13 strings, and the third nominal voltage and the first nominal voltage share a second battery pack of 9 strings or 8 strings.

[0062] Specifically, the first nominal voltage is 60V, the second nominal voltage is 72V, and the third nominal voltage is 48V. Figure 1 This is the circuit diagram for a battery pack with a nominal voltage of 60V. Figure 2 This is the circuit diagram for a battery pack with a nominal voltage of 72V. Figure 3 This is a circuit diagram for a battery pack with a nominal voltage of 48V. Figures 1-3 The circuit structures are the same, the difference lies in the combination of battery strings. The battery string is represented by S. Figure 1 In the context of a nominal 60V voltage: 13S + 9S = 22S, Figure 2 In the nominal 72V: 13S + 13S = 26S, Figure 3 In the case of a nominal 48V: 8S + 9S = 17S.

[0063] In this embodiment, the main battery pack and sub-battery pack use sodium batteries, and the rated voltage of each sodium battery string is approximately 2.8V.

[0064] When the first battery pack has 13 cells in series and the second battery pack has 9 cells in series, a total of 22 cells can provide the first nominal voltage. Alternatively, the first battery pack can also provide the first nominal voltage when it has 13 cells in series and the second battery pack has 9 cells in series.

[0065] When both the first and second battery packs have 13 cells in series, a second nominal voltage can be provided. Alternatively, when both the first and second battery packs have 13 cells in series, a second nominal voltage can also be provided.

[0066] When the first battery pack has 8 cells and the second battery pack has 9 cells, a third nominal voltage can be provided. Alternatively, when the first battery pack has 8 cells and the second battery pack has 8 cells, a total of 16 cells can be provided, which can also provide a third nominal voltage.

[0067] For battery packs with nominal voltages of 48V, 60V, and 72V, six different combinations would be required if the battery strings were arbitrarily combined. However, in this embodiment, a first battery pack with 13 strings shared by the first and second nominal voltages, and a second battery pack with 9 or 8 strings shared by the third nominal voltage and the first nominal voltage, can be combined in pairs to obtain three different battery pack specifications. Therefore, this significantly reduces the number of production lines, thereby lowering production and maintenance costs.

[0068] exist Figure 1 In the first three-terminal fuse 112, the first battery pack 111 is connected; the first control unit 113 is connected to the control terminal of the first three-terminal fuse 112.

[0069] Specifically, the first three-terminal fuse is a safety-certified three-terminal fuse, used as a one-time safety protection switch for abnormal operating conditions. That is, the first three-terminal fuse is used for overcurrent protection, short circuit protection, or overvoltage protection of the circuit, thereby protecting the safety of the first battery pack.

[0070] exist Figure 1 In the diagram, the first three-terminal fuse 112 is marked FS-L and has three terminals: terminal 1, terminal 2, and terminal 3. Terminal 2 is the control terminal and is connected to the first control unit. The first control unit can be an MCU control chip.

[0071] exist Figure 1 In this configuration, a diode DF and a resistor RF are connected between terminals 1 and 3 of the first three-terminal fuse FS-L. Resistor RF has a resistance of 10KΩ and a rated power of 2W. Additionally, terminal 1 of the first three-terminal fuse FS-L can be connected to the first battery pack BT-L via resistor RS-L. The specifications for the first three-terminal fuse FS-L are a rated voltage of 120V, consisting of two 45A fuses connected in parallel, and resistor RF has a resistance of 10KΩ and a rated power of 2W.

[0072] exist Figure 1 In the circuit, MOS circuit 122 is connected to the first battery pack 111 and the second battery pack 121. MOS circuit 122 is used to control the on / off state of the charging and discharging circuit after the main battery pack 11 and the sub-battery pack 12 are connected in series. The second control unit 123 is connected to the control terminals of multiple MOS transistors in MOS circuit 122.

[0073] The second control unit 123 can also be an MCU control chip.

[0074] In this embodiment, the MOS circuit is located in the sub-battery pack, and the main battery pack does not contain the MOS circuit. If the battery pack is mass-produced, half of the MOS circuit is saved, thereby reducing the production cost of the battery pack.

[0075] In some specific implementations, in Figure 1 In the MOS circuit 122, multiple MOS transistors are located in the middle of the series connection between the main battery pack 11 and the sub-battery pack 12. The MOS circuit 122 includes: a main control circuit 1221, a first MOS transistor 1222, and a second MOS transistor 1223.

[0076] exist Figure 1 In the middle, the main control circuit 1221 is connected between the first battery pack 111 and the second battery pack 122.

[0077] exist Figure 1 In the main control circuit 1221, there are MOSFETs QCN-1, QCN-n, QDN-1, and QDN-n. A bidirectional diode UD-1 with a rated voltage of 12V is connected between the control terminal and the source terminal of MOSFET QDN-1. A capacitor CBB-1 is connected between the control terminal and the drain terminal of MOSFET QDN-1. Similarly, a bidirectional diode UD-n with a rated voltage of 12V is connected between the control terminal and the source terminal of MOSFET QDN-n. A capacitor CBB-n is connected between the control terminal and the drain terminal of MOSFET QDN-n. The control terminals of all the MOSFETs in the main control circuit are connected to the second control unit 123.

[0078] exist Figure 2 In the main control circuit 1221, there are also multiple resistors: RS-H1, RS-Hn, RW-1, and RW-n1. RS-H1 and RS-Hn have a resistance of 10mΩ and a rated voltage of 2W. RW-1 and RW-n1 have a resistance of 50mΩ and a rated voltage of 4W. Two resistors with a certain resistance value, such as 10Ω, can be connected between RS-H1 and RS-Hn.

[0079] The main control circuit 1221 is connected to the second battery pack BT-H through resistor RS-H1, and the main control circuit 1221 is connected to the first battery pack BT-L through MOSFET QCN-1 and second three-terminal fuse FS-H.

[0080] exist Figure 1 In the first MOSFET 1222, its source terminal is connected to the main control circuit 1221, and its control terminal is connected to the second control unit 123.

[0081] exist Figure 1In this circuit, the first MOSFET 1222 is identified as QCN-B, and the second MOSFET is identified as QDN-B. Their control terminals are connected to the second control unit 123.

[0082] exist Figure 1 In the first MOSFET 1222, the source terminal of the second MOSFET 1223 is connected to the drain terminal of the first MOSFET 1222 through a bypass resistor 125, the control terminal of the second control unit 123 is connected to the source terminal of the main control circuit 1221.

[0083] exist Figure 1 In the circuit, the bypass resistor 125 is marked as CPTC, and its resistance is 25Ω.

[0084] In this embodiment, after the main battery pack and the sub-battery pack are connected in series, the MOS circuit is located in the middle of the battery pack during its charging and discharging process, which reduces the cost of using the MOS circuit by half. That is, it reduces the cost of using multiple MOS transistors and resistors in the MOS circuit, thereby greatly reducing the production cost of the battery pack.

[0085] In one specific implementation, in Figure 1 The battery pack 12 also includes: an LDO chip 124, a bypass resistor 125, and an optocoupler 126. The LDO chip is a low-dropout linear regulator chip.

[0086] exist Figure 1 In the circuit, LDO chip 124 is connected to MOS circuit 122 and external power supply. It is used to connect the output voltage of the external power supply, controlling the first MOS transistor 1222 to turn on, thereby charging the first battery pack 111 and the second battery pack 121 through the external power supply. The external power supply... Figure 1 As not shown, the external power supply is connected through the P+ port.

[0087] exist Figure 1 In this LDO chip, the rated voltage is 80V. Its input terminal is connected to two diodes D0V-1 and D0V-2. The external power supply is connected through diode D0V-1, and the external power supply can be connected through the P+ port.

[0088] exist Figure 1 In the middle, the bypass resistor 125 is used to assist in turning on the first MOSFET 1222.

[0089] exist Figure 1 In the circuit, the bypass resistor 125 is marked as CPTC, and it is connected between the first MOSFET QCN-B and the second MOSFET QDN-B.

[0090] exist Figure 1In the middle, the optocoupler 126 is connected to the second control unit 123. When the charging power obtained by the first battery pack 111 and the second battery pack 121 meets the requirements, the second control unit 123 obtains the optocoupler signal and controls the output terminal of the LDO chip 124 to connect with the source terminal of the first MOS transistor 1222, so that the gate-source voltage of the first MOS transistor 1222 in the MOS circuit 122 is zero, disconnecting the first MOS transistor in the MOS circuit 122, and charging through the main control circuit 1221.

[0091] exist Figure 1 In this design, optocoupler 126 is designated OP-0V. Terminal 1 of OP-0V is connected to the second control unit 123 via resistor R0V-1, terminal 3 is grounded, and terminal 4 is connected to the ground terminal of the LDO chip and diode D0V-2. Terminal 4 of OP-0V is also connected to the control terminal of the first MOSFET QCN-B and, via resistor R0V-2, to the source terminal of the first MOSFET QCN-B. The resistance values ​​of resistors R0V-1 and R0V-2 can be 2KΩ.

[0092] This embodiment, through the aforementioned LDO chip, bypass resistor, and optocoupler, can not only achieve normal charging of the first and second battery packs, but also achieve 0V charging of the first and second battery packs when the external power supply is disconnected.

[0093] In one specific implementation, in Figure 1 The battery pack 12 also includes a second three-terminal fuse 127, the control terminal of which is connected to the second control unit 123.

[0094] Specifically, the second and third-terminal fuses are safety-certified three-terminal fuses, serving as a one-time safety protection switch for abnormal operating conditions. That is, the second and third-terminal fuses are used for overcurrent protection, short-circuit protection, or overvoltage protection, thereby protecting the safety of the second battery pack. Figure 1 In this configuration, the second three-terminal fuse is FS-H, which has three terminals: terminal 1, terminal 2, and terminal 3. Terminal 2 is the control terminal and is connected to the second control unit. The second three-terminal fuse FS-L has a rated voltage of 120V and consists of two 45A fuses connected in parallel.

[0095] exist Figure 1 In the middle, terminal 1 of the second three-terminal fuse FS-H is connected to the source terminal of the first MOSFET QCN-B, and terminal 3 of the second three-terminal fuse is connected to the second battery pack BT-L.

[0096] In one specific implementation, in Figure 1In the process, a communication line 13 and a charging line 14 are provided between the main battery pack 11 and the sub-battery pack 12. The communication line 13 is used to establish a communication connection between the first control unit 113 and the second control unit 123.

[0097] Specifically, in Figure 1 In the communication line 13, there are communication units and communication interfaces L-1 on the main battery pack 11 side and communication units and communication interfaces H-1 on the sub-battery pack 12 side. The communication unit on the main battery pack 11 side includes two transistors QN-1 and QN-2 connected in parallel. The collector of transistor QN-2, as the receiving terminal RXD-L, is connected to the receiving pin RXD-L of the first control unit 113. The receiving pin RXD-L of the first control unit 113 is connected to the receiving pin RXD of the second control unit 123. The upper end of the base of transistor QN-2 is connected to terminal 1 of the communication interface through a resistor with a resistance value of 100KΩ. The lower end of the base of transistor QN-2 is grounded through a resistor with a resistance value of 20KΩ. The emitter of transistor QN-2 is connected to the ground of the communication interface through an emitter resistor, and the emitter of transistor QN-2 is also grounded. The upper base of transistor QN-1 is connected to the emitter pin TXD-L of the first control unit 113 via a resistor serving as the emitter terminal TXD-L. The emitter pin RXD-L of the first control unit 113 is connected to the receiver pin TXD of the second control unit 123. The lower base of transistor QN-1 is grounded via a resistor with a resistance of 20KΩ. The collector of transistor QN-1 is connected to terminals 2 of the communication interface via a collector resistor with a resistance of 100KΩ. The emitter of transistor QN-1 is also grounded.

[0098] exist Figure 1The communication unit on the side of the sub-battery pack 12 includes four transistors: QP-1, QP-2, QP-3, and QP-4. The upper base of transistor QN-3 is connected to the emitter pin TXD of the second control unit 123 via resistor U3, and the lower base of transistor QN-3 is grounded via resistor U5. Both resistors U3 and U5 have a resistance of 20KΩ. The upper base of transistor QN-2 is connected to the P+ port via a resistor with a resistance of 20KΩ. The lower base of transistor QN-2 is connected to its collector via a resistor with a resistance of 20KΩ. The collector of transistor QN-2 is connected to terminal 4 of communication interface H-1 via a collector resistor with a resistance of 100KΩ. The emitter of transistor QP-2 is connected to the P+ port. The emitter of transistor QP-1 is connected to the P+ port. The collector of transistor QP-1 is connected to the base of transistor QN-4 through a collector resistor with a resistance of 20KΩ. The upper end of the base of transistor QP-1 is connected to the P+ port through a resistor with a resistance of 20KΩ. The lower end of the base of transistor QP-1 is connected to pin 3 of communication interface H-1 through a resistor with a resistance of 100KΩ. The collector of transistor QN-4, serving as the receiver (RXD), is connected to the receive pin (RXD) of the second control unit. The emitter of transistor QN-4 is grounded, and the base of transistor QN-4 is grounded through a resistor U2 with a resistance of 20KΩ.

[0099] exist Figure 1 In the diagram, charging line 14 is the rightmost line connected to terminals 1 and 2 of communication interface H-1, and terminals 3 and 4 of communication interface L-1. The charging line is used to charge the charging load.

[0100] In one specific implementation, in Figure 1 In the middle, the main battery pack 11 also includes:

[0101] The power absorption circuit 114 is connected to the first three-terminal fuse 112 and the charging line 14, and is used to absorb the power of the charging line 14 when a load to be charged is connected between the main battery pack 11 and the sub-battery pack 12.

[0102] exist Figure 1 In the circuit, the power absorption circuit 114 includes a reverse diode DW1, a capacitor CW1, and a charging interface U-CHG. One end of the reverse diode DW1 and capacitor CW1 connected in parallel is connected to terminals 3 and 4 of the communication interface. The other end of the reverse diode DW1 and capacitor CW1 connected in parallel is connected to the P-port.

[0103] When a load to be charged is connected between the P- port and the P+ port, at the moment the battery pack supplies power to the outside, the external inductive load to be charged will generate a reverse electromotive force. Through this energy absorption circuit, the reverse electromotive force is absorbed and dissipated, thus avoiding damage to the core components of the battery pack.

[0104] When an external power supply is connected between the P- port and the P+ port, the reverse diode DW1 is turned off due to reverse bias, so the energy absorption circuit does not work.

[0105] In one specific implementation, in Figure 1 In the middle, the main battery pack 11 also includes:

[0106] The communication chip 115 is connected to the first control unit 113 and the user terminal, and is used to transmit the operating status information of the main battery pack 11 and the sub-battery pack 12 to the user.

[0107] Specifically, the communication chip includes, but is not limited to, Bluetooth chips or Wi-Fi chips. This communication chip is connected to the first control unit and also to the user terminal. For example, the communication chip enables a wireless connection with the user's mobile phone terminal, allowing the user to check the battery pack's operating status information.

[0108] In one specific implementation, in Figure 1 In the middle, the main battery pack 11 also includes:

[0109] The first analog front-end circuit 116 is connected to the first battery pack 111 and is used to sample the key parameters of the first battery pack 111.

[0110] Sub-battery pack 12 also includes:

[0111] The second analog front-end circuit 128 is connected to the second battery pack 121 and is used to sample key parameters of the second battery pack 121.

[0112] The first analog front-end circuit 116 and the second analog front-end circuit 128, abbreviated as AFE, are key nodes connecting the analog signal sensor and the digital signal processor. In the battery management system (BMS), it specifically refers to the battery sampling chip, which is responsible for collecting key data such as battery cell voltage and temperature.

[0113] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery pack suitable for electric vehicles, comprising: A main battery pack and a sub-battery pack connected in series with the main battery pack, characterized in that the main battery pack comprises: First battery pack; The first three-terminal fuse is connected to the first battery pack; The first control unit is connected to the control terminal of the first three-terminal fuse; The sub-battery pack includes: Second battery pack; A MOS circuit is connected to the first battery pack and the second battery pack. The MOS circuit is used to control the on / off state of the charging and discharging circuit of the main battery pack and the sub-battery pack connected in series. The second control unit is connected to the control terminals of multiple MOS transistors in the MOS circuit.

2. The battery pack for electric vehicles according to claim 1, characterized in that, The MOS circuit comprises multiple MOS transistors located in the middle of the series connection between the main battery pack and the sub-battery pack. The main control circuit is connected between the first battery pack and the second battery pack; The first MOSFET has its source terminal connected to the main control circuit and its control terminal connected to the second control unit. The second MOSFET has its drain terminal connected to the drain terminal of the first MOSFET via a bypass resistor, its control terminal connected to the second control unit, and its source terminal connected to the main control circuit.

3. The battery pack for electric vehicles according to claim 2, characterized in that, The sub-battery pack also includes: The LDO chip is connected to the MOS circuit and the external power supply. It is used to turn on the output voltage of the external power supply, control the first MOS transistor to turn on, and then charge the first battery pack and the second battery pack through the external power supply. The bypass resistor is used to assist the first MOS transistor in turning on; An optocoupler, connected to the second control unit, is used to obtain an optocoupler signal through the second control unit when the charging power obtained by the first battery pack and the second battery pack meets the requirements, and control the output terminal of the LDO chip to connect to the source terminal of the first MOS transistor, so that the gate-source voltage of the first MOS transistor in the MOS circuit is zero, disconnecting the first MOS transistor in the MOS circuit, and charging through the main control loop.

4. The battery pack for electric vehicles according to claim 1, characterized in that, The sub-battery pack also includes a second three-terminal fuse, the control terminal of which is connected to the second control unit.

5. The battery pack for electric vehicles according to claim 1, characterized in that, A communication line and a charging line are provided between the main battery pack and the sub-battery pack, wherein the communication line is used to establish a communication connection between the first control unit and the second control unit.

6. The battery pack for electric vehicles according to claim 5, characterized in that, The main battery pack also includes: An energy absorption circuit, connected to the first three-terminal fuse and the charging line, is used to absorb the energy of the charging line when a load to be charged is connected between the main battery pack and the sub-battery pack.

7. The battery pack for electric vehicles according to claim 5, characterized in that, The main battery pack also includes: A communication chip, connected to the first control unit and the user terminal, is used to transmit operating status information of the main battery pack and the sub-battery pack to the user.

8. The battery pack for electric vehicles according to claim 1, characterized in that, The number of battery strings in the first battery pack includes 13 or 8 strings, and the number of battery strings in the second battery pack includes 13, 12, 9, or 8 strings.

9. The battery pack for electric vehicles according to claim 8, characterized in that, The first battery pack, which shares 13 strings with the first nominal voltage and the second nominal voltage, and the second battery pack, which shares 9 or 8 strings with the third nominal voltage and the first nominal voltage.

10. A battery pack suitable for electric vehicles according to any one of claims 1 to 9, characterized in that, The main battery pack also includes: A first analog front-end circuit is connected to the first battery pack and is used to sample key parameters of the first battery pack. The sub-battery pack also includes: The second analog front-end circuit is connected to the second battery pack and is used to sample key parameters of the second battery pack.

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