Battery protection circuit of electric power-assisted bicycle

Abstract

The utility model provides a battery protection circuit of an electric power-assisted bicycle, and relates to the technical field of electric power-assisted bicycles. The circuit comprises a battery assembly, a power management chip, a control unit, a current sampling circuit, a charging and discharging control circuit and a fusing circuit, wherein each battery unit in the battery assembly is respectively connected with the power management chip, the positive electrode of the battery assembly is connected with the positive charge-discharge interface through the fuse, the negative electrode of the battery assembly is connected with the negative charge-discharge interface through the charge-discharge control circuit, and the current sampling circuit is connected between the charge-discharge control circuit and the negative electrode of the battery assembly; the current sampling circuit is further connected with the power management chip, the power management chip is further connected with the charging and discharging control circuit, the power management chip is further connected with the control unit, the control unit is connected with the fusing circuit, and the fusing circuit is connected with the fuse. Therefore, detection of over-current, over-voltage, under-voltage, over-temperature and other problems can be realized, and when the charging and discharging control circuit is broken down, the fuse is controlled to be fused, so that the safety of the circuit is ensured.

Description

Technical Field

[0001] The present application relates to the technical field of electric-assisted bicycles, and in particular to a battery protection circuit for electric-assisted bicycles. Background Art

[0002] In the field of electric-assisted bicycle technology, the drive system provides auxiliary power when the user is riding or pushing the bicycle. The batteries in this drive system are typically high-performance lithium-ion batteries. As a power storage tool, lithium-ion batteries are extremely demanding in their application environment. Overcharging and over-discharging are the most common concerns during use, resulting in poor thermal stability and consistency, as well as a flat discharge voltage curve.

[0003] To obtain a higher lithium-ion battery voltage, many single cells are generally required to be connected in series. After multiple single cells are connected in parallel into a group, the voltage, capacity and other parameters of the lithium-ion battery will be inconsistent due to differences in battery materials, processes and subsequent usage environment within the group. If no measures are taken, the lithium-ion inconsistency will further expand during subsequent use, causing some batteries to operate at the limit state for a long time, resulting in a sharp decrease in the capacity of the lithium-ion battery and reducing the performance of the entire lithium-ion battery group.

[0004] Therefore, battery protection circuits are generally used in applications where lithium-ion batteries are used to ensure battery safety. Utility Model Content

[0005] The purpose of this application is to provide a battery protection circuit for an electric assisted bicycle, which can protect the battery protection circuit from overcurrent, overvoltage, undervoltage and other problems by detecting the charging and discharging current of the battery assembly. After the above problems continue to occur for a preset duration, the charging and discharging control circuit is broken down, and the fuse is controlled to blow to ensure the safety of the battery.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present application are as follows:

[0007] In a first aspect, an embodiment of the present application provides a battery protection circuit for an electric-assisted bicycle, the battery protection circuit comprising: a battery assembly, a power management chip, a control unit, a current sampling circuit, a charge and discharge control circuit, and a fuse circuit;

[0008] In which, each battery cell in the battery assembly is respectively connected to the power management chip, the positive pole of the battery assembly is connected to the positive charge and discharge interface through a fuse, the negative pole of the battery assembly is grounded, and the negative pole of the battery assembly is also connected to the negative charge and discharge interface through the charge and discharge control circuit. The current sampling circuit is connected between the charge and discharge control circuit and the negative pole of the battery assembly to detect the charge and discharge current of the battery assembly; the current sampling circuit is also connected to the power management chip, the power management chip is also connected to the charge and discharge control circuit, the power management chip is also connected to the control unit, the control unit is connected to the fuse circuit, and the fuse circuit is connected to the fuse; wherein, the control unit is used to receive the overvoltage signal of the power management chip of a preset duration, or the overcurrent signal of the current sampling circuit, to control the fuse to blow.

[0009] Optionally, the battery protection circuit further includes: a voltage detection circuit, wherein the voltage detection circuit is connected to the positive electrode of the battery assembly to detect the charge and discharge voltage of the battery assembly, and the voltage detection circuit is also connected to the control unit.

[0010] Optionally, the battery protection circuit further includes: a temperature sampling circuit, which is arranged at a preset position near the battery assembly to detect the temperature of the battery assembly, and the temperature sampling circuit is connected to the power management chip and the control unit; wherein the control unit is further used to receive an over-temperature signal from the temperature sampling circuit of the preset duration to control the fuse to blow.

[0011] Optionally, the current sampling circuit includes: a first resistor, a second resistor and a third resistor, the first resistor is connected between the charge and discharge control circuit and the negative electrode of the battery assembly, and the two ends of the first resistor are also connected to the power management chip through the second resistor and the third resistor respectively.

[0012] Optionally, the temperature sampling circuit includes: multiple sampling units, each sampling unit is arranged at a preset position close to one or more battery cells in the battery assembly, and the multiple sampling units are connected to the power management chip and the control unit.

[0013] Optionally, each sampling unit includes: a thermistor and a voltage divider resistor, one end of the voltage divider resistor is used to receive a preset voltage signal, the voltage divider resistor is connected to one end of the thermistor, the other end of the thermistor is grounded, and one end of the thermistor is connected to the power management chip and the control unit.

[0014] Optionally, the battery protection circuit further includes: a DC step-down circuit, wherein the input end of the DC step-down circuit is connected to the positive electrode of the battery assembly, the first output end of the DC step-down circuit is connected to the fuse circuit, and the second output end of the DC step-down circuit is connected to the control unit.

[0015] Optionally, the fuse circuit includes: a first switch unit and a second switch unit, the first end of the first switch unit is connected to the control unit, the second end of the first switch unit is grounded, the third end of the first switch unit is connected to the first end of the second switch unit, the second end of the second switch unit is connected to the second output end of the DC step-down circuit, and the third end of the second switch unit is connected to the fuse.

[0016] Optionally, the first switching unit includes: a first transistor, a fourth resistor and a fifth resistor, the base of the first transistor is connected to one end of the fourth resistor, the other end of the fourth resistor is the first end of the first switching unit, and is used to connect to the control unit, the base of the first transistor is connected to the emitter of the first transistor through the fifth resistor, the emitter of the first transistor is the second end of the first switching unit, the emitter of the first transistor is also grounded, and the collector of the first transistor is the third end of the first switching unit.

[0017] Optionally, the second switch unit includes: a second transistor, a sixth resistor, a seventh resistor, a field-effect transistor, an eighth resistor and a ninth resistor, the base of the second transistor is connected to one end of the sixth resistor, the other end of the sixth resistor is the first end of the second switch unit, used to connect to the third end of the first switch unit, the emitter of the second transistor is the second end of the second switch unit, used to connect to the second output end of the DC step-down circuit, the base of the second transistor is connected to the emitter of the second transistor through the sixth resistor, the collector of the second transistor is connected to the gate of the field-effect transistor through the eighth resistor, the drain of the field-effect transistor is the third end of the second switch unit, used to connect to the fuse, the drain of the field-effect transistor is connected to the source of the field-effect transistor through the sixth resistor, and the source of the field-effect transistor is also grounded.

[0018] The battery protection circuit of the electric power-assisted bicycle provided by this application has the following beneficial effects:

[0019] The present application provides a battery protection circuit for an electric power-assisted bicycle, which consists of a battery assembly, a power management chip, a control unit, a current sampling circuit, a charge and discharge control circuit, and a fuse circuit; wherein, each battery cell in the battery assembly is connected to the power management chip, the positive electrode of the battery assembly is connected to the positive charge and discharge interface through a fuse, the negative electrode of the battery assembly is connected to the negative charge and discharge interface through the charge and discharge control circuit, the current sampling circuit is connected between the charge and discharge control circuit and the negative electrode of the battery assembly to detect the charge and discharge current of the battery assembly; the current sampling circuit is also connected to the power management chip, the power management chip is also connected to the charge and discharge control circuit, the power management chip is also connected to the control unit, the control unit is connected to the fuse circuit, the fuse circuit is connected to the fuse, wherein the control unit is used to receive an overvoltage signal of the power management chip of a preset duration, or an overcurrent signal of the current sampling circuit, to control the fuse to melt. Thus, the present application detects overcurrent and overvoltage problems during the charge and discharge process of the battery assembly, and after the overcurrent or overcurrent problem lasts for a preset duration, the charge and discharge control circuit is broken down, and then controls the fuse to melt. Among them, controlling the charge and discharge control circuit is the first protection of the battery protection circuit of the electric power-assisted bicycle, and controlling the fuse to melt is the second protection of the battery protection circuit of the electric power-assisted bicycle, ensuring the safety of the battery protection circuit of the electric power-assisted bicycle and improving the reliability of the battery protection circuit of the electric power-assisted bicycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0021] Figure 1 A schematic structural diagram of a drive system for an electric-assisted bicycle provided in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 1 ;

[0023] Figure 3 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 2 ;

[0024] Figure 4 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 3 ;

[0025] Figure 5 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 4 ;

[0026] Figure 6 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 5 ;

[0027] Figure 7 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 6 ;

[0028] Figure 8 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 7 ;

[0029] Figure 9 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 8 ;

[0030] Figure 10 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 9 ;

[0031] Figure 11 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 10 ;

[0032] Figure 12 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 10 one. DETAILED DESCRIPTION

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0036] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is typically placed when in use. These terms are intended only to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0038] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0039] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features therein may be combined with each other.

[0040] To better understand the various solutions provided in the embodiments of the present application, the battery protection circuit of an electric-assisted bicycle provided in the embodiments of the present application is described in detail below in conjunction with the accompanying drawings.

[0041] Before explaining the battery protection circuit of the electric assisted bicycle, the drive system of the electric assisted bicycle is explained in detail.

[0042] Figure 1 This is a schematic diagram of the structure of a drive system of an electric assisted bicycle provided in an embodiment of the present application. Figure 1As shown, the driving system 200 of the electric-assisted bicycle may include: a battery protection circuit 100 , an instrument device 210 , a sensor 220 and a motor assembly 230 .

[0043] The meter device 210 , the sensor 220 and the motor assembly 230 are all connected to the control unit in the battery protection circuit 100 .

[0044] The driving system 200 of the electric-assisted bicycle can generate a thrust force when the electric-assisted bicycle is ridden, thereby assisting the electric-assisted bicycle to move forward.

[0045] It should be noted that, in addition to the battery protection circuit 100, the instrument device 210, the sensor 220 and the motor assembly 230, the driving system 200 of the electric-assisted bicycle also has other components, such as a bus, etc., which are not limited here.

[0046] The driving system of the electric-assisted bicycle provided in the embodiment of the present application can be composed of a battery protection circuit, instrument equipment, sensors, and motor components. The instrument equipment, sensors, and motor components can be controlled and data exchanged through a control unit in the battery protection circuit to generate a thrust when riding the electric-assisted bicycle and assist the electric-assisted bicycle to move forward.

[0047] The following is an illustrative description of the battery protection circuit of the electric-assisted bicycle provided in the embodiments of the present application with reference to the accompanying drawings.

[0048] Figure 2 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 1 .like Figure 2 As shown, the battery protection circuit 100 may include: a battery assembly 110 , a power management chip 120 , a control unit 130 , a current sampling circuit 140 , a charge and discharge control circuit 150 , and a fuse circuit 160 .

[0049] The control unit 130 is configured to receive an overvoltage signal of a preset duration from the power management chip 120 or an overcurrent signal from the current sampling circuit 140 to control the fuse to blow. The preset duration can be selected based on actual conditions. For example, the preset duration can be selected to be 100ms.

[0050] Among them, each battery cell in the battery assembly 110 is respectively connected to the power management chip 120, which is used for the power management chip 120 to manage each battery cell in the battery assembly 110; the positive pole of the battery assembly 110 is connected to the positive charge and discharge interface through a fuse, and the negative pole of the battery assembly 110 is connected to the negative charge and discharge interface through the charge and discharge control circuit 150, which is used to charge and discharge the battery assembly 110; the negative pole of the battery assembly 110 is also grounded; the current sampling circuit 140 is connected between the charge and discharge control circuit 150 and the negative pole of the battery assembly 110 to detect the charge and discharge current of the battery assembly 110, so as to infer whether the battery assembly 110 has an overcurrent problem during charging or whether there is an overcurrent problem during discharging; the current sampling circuit 140 is also connected to the power management chip 120, and the power management chip 120 is also connected to the charge and discharge control circuit 150, which is used for the power management chip 120 to send a shutdown signal to disconnect the charging or discharging of the battery assembly 110 through the charge and discharge control circuit 150 when it determines that the charging is overcurrent or the discharging is overcurrent.

[0051] The power management chip 120 is also connected to the control unit 130, and the control unit 130 is connected to the fuse circuit 160. After the control unit 130 receives the overcurrent signal from the battery management chip 120, and the overcurrent signal may exist for a preset duration (such as 100ms), it can control the issuance of a fuse signal; since the fuse circuit 160 is connected to the fuse, the fuse FUSE can be controlled to blow through the fuse signal.

[0052] The battery assembly 110 is composed of multiple battery cells connected in series. The power management chip 120 can be selected based on actual conditions, for example, the power management chip 120 can be selected as a DVC1117 power management chip. The control unit 130 can be selected based on actual conditions, for example, the control unit 130 can be selected as an MCU (Microcontroller Unit). The charge and discharge control circuit 150 can be selected based on actual conditions, for example, the charge and discharge control circuit 150 can be selected as a single NMOS transistor or multiple NMOS transistors connected in parallel.

[0053] The present application provides a battery protection circuit for an electric power-assisted bicycle, which consists of a battery assembly, a power management chip, a control unit, a current sampling circuit, a charge and discharge control circuit, and a fuse circuit; wherein, each battery cell in the battery assembly is connected to the power management chip, the positive electrode of the battery assembly is connected to the positive charge and discharge interface through a fuse, the negative electrode of the battery assembly is grounded, the negative electrode of the battery assembly is also connected to the negative charge and discharge interface through the charge and discharge control circuit, the current sampling circuit is connected between the charge and discharge control circuit and the negative electrode of the battery assembly to detect the charge and discharge current of the battery assembly; the current sampling circuit is also connected to the power management chip, the power management chip is also connected to the charge and discharge control circuit, the power management chip is also connected to the control unit, the control unit is connected to the fuse circuit, the fuse circuit is connected to the fuse, wherein the control unit is used to receive an overvoltage signal of the power management chip of a preset duration, or an overcurrent signal of the current sampling circuit, to control the fuse to melt. Thus, the present application detects overcurrent and overvoltage problems during the charge and discharge process of the battery assembly, and after the overcurrent or overcurrent problem lasts for a preset duration, the charge and discharge control circuit is broken down, and then controls the fuse to melt. Among them, controlling the charge and discharge control circuit is the first protection of the battery protection circuit of the electric power-assisted bicycle, and controlling the fuse to melt is the second protection of the battery protection circuit of the electric power-assisted bicycle, ensuring the safety of the battery protection circuit of the electric power-assisted bicycle and improving the reliability of the battery protection circuit of the electric power-assisted bicycle.

[0054] exist Figure 2 On this basis, the battery protection circuit of the electric-assisted bicycle provided in the embodiment of the present application is described below with reference to the accompanying drawings. Figure 3 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 2 .like Figure 3 As shown, the battery protection circuit 100 may further include: a voltage detection circuit 170 .

[0055] The voltage detection circuit 170 is connected to the positive terminal of the battery assembly 110 to detect the charge and discharge voltages of the battery assembly 110, thereby inferring whether the battery assembly 110 has an overvoltage problem during charging or an undervoltage problem during discharging. The voltage detection circuit 170 is also connected to the control unit 130. When the power management chip 120 detects an overvoltage state during charging or an undervoltage state during discharging of the battery assembly 110, the power management chip 120 can be configured to issue a shutdown signal to disconnect the charging or discharging of the battery assembly 110 through the charge and discharge control circuit 150. If the control unit 130 detects an overvoltage state during charging or an undervoltage state during discharging of the battery assembly 110 through the voltage detection circuit 170, and the overvoltage or undervoltage state exceeds a preset duration threshold (e.g., 100ms), the control unit 130, connected to the fuse circuit 160, issues a fuse signal to control the fuse circuit 160 to open the fuse FUSE, thereby ensuring the safety of the battery protection circuit of the electric-assisted bicycle.

[0056] It should be noted that the voltage detection circuit 170 may include a voltage dividing unit, which is mainly used to detect the overvoltage state of the battery assembly 110 during the charging process and the undervoltage state during the discharging process.

[0057] The present application provides a battery protection circuit for an electric-assisted bicycle. The battery protection circuit may further include a voltage detection circuit, which is connected to the positive electrode of the battery assembly to detect the charge and discharge voltage of the battery assembly. The voltage detection circuit is also connected to a control unit. Thus, the present application detects problems such as overvoltage or undervoltage during the charge and discharge process of the battery assembly by detecting the charge and discharge voltage of the battery assembly. After the above problems continue to occur for a preset duration, the charge and discharge control circuit is broken down, and the fuse is controlled to melt, thereby realizing the detection of overvoltage or undervoltage problems by the battery protection circuit of the electric-assisted bicycle, ensuring the safety of the battery protection circuit of the electric-assisted bicycle, and improving the reliability of the battery protection circuit of the electric-assisted bicycle.

[0058] exist Figure 3 On this basis, the battery protection circuit of the electric-assisted bicycle provided in the embodiment of the present application is described below with reference to the accompanying drawings. Figure 4 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 3 .like Figure 4 As shown, the battery protection circuit 100 may further include a temperature sampling circuit 180 .

[0059] The control unit 130 is further configured to receive an over-temperature signal from the temperature sampling circuit 180 with a preset duration (eg, 100 ms) to control the fuse to blow.

[0060] The temperature sampling circuit 180 is disposed at a preset position near the battery assembly 110, so that the temperature sampling circuit 180 is physically close to one or more battery cells in the battery assembly 110, and is used to detect the temperature of the battery assembly 110 (including multiple battery cells). The temperature sampling circuit 180 is electrically connected to the power management chip 120 and the control unit 130. The preset position can be selected based on the actual PCB board and the battery cells, that is, the temperature sampling circuit 180 on the PCB board can collect the temperature of the battery assembly 110 (including multiple battery cells).

[0061] When the temperature sampled by the temperature sampling circuit 180 exceeds a preset temperature threshold, the power management chip 120 is configured to issue a shutdown signal based on the determination that the temperature exceeds the preset temperature threshold. This shutdown signal is transmitted through the charge and discharge control circuit 150 to disconnect the battery assembly 110 from charging and discharging. The control unit 130 is configured to issue a fusing signal based on the preset temperature threshold and a preset duration (e.g., 100 ms) to control the fusing circuit 160 to blow the fuse FUSE. The preset temperature threshold can be selected based on actual conditions. For example, the preset temperature threshold can be selected as 70±5 degrees Celsius.

[0062] The present application provides a battery protection circuit for an electric-assisted bicycle. The battery protection circuit may further include a temperature sampling circuit. The temperature sampling circuit is arranged at a preset position near the battery assembly to detect the temperature of the battery assembly. The temperature sampling circuit is connected to the power management chip and the control unit. Thus, the present application detects overheating problems during the charging and discharging process of the battery assembly by collecting the temperature of the battery assembly in real time. After the above problem continues for a preset duration, the charge and discharge control circuit is broken down, and the fuse is controlled to melt, thereby realizing the detection of overheating problems by the battery protection circuit of the electric-assisted bicycle, ensuring the safety of the battery protection circuit of the electric-assisted bicycle, and improving the reliability of the battery protection circuit of the electric-assisted bicycle.

[0063] exist Figure 4 On this basis, the battery protection circuit of the electric-assisted bicycle provided in the embodiment of the present application is described below with reference to the accompanying drawings. Figure 5 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 4 .like Figure 5 As shown, the current sampling circuit 140 may include: a first resistor R1, a second resistor R2 and a third resistor R3.

[0064] Among them, the first resistor R1 is connected between the charge and discharge control circuit 150 and the negative electrode of the battery assembly 110. The two ends of the first resistor R1 are also connected to the power management chip 120 through the second resistor R2 and the third resistor R3, so that when the battery assembly 110 is charging, the current flows through the first resistor R1 to the charge and discharge control circuit 150 to the negative charge and discharge interface; when discharging, the current flows through the preset load to the negative charge and discharge interface to the charge and discharge control circuit 150, and then to the first resistor R1. In other words, the current detection in this application is actually to detect the voltage across the first resistor R1, and then divide the voltage difference across the first resistor R1 by the resistance value of the first resistor R1 to obtain the real-time current.

[0065] It should be noted that, since there is a voltage difference between the two ends of the first resistor R1 during the charging and discharging process of the battery assembly 110, it is possible to determine whether the battery assembly 110 is in a charging state or a discharging state based on the voltage difference between the two ends of the first resistor R1. Figure 5 As shown, if the voltage on the left side of the first resistor R1 is higher than the voltage on the right side of the first resistor R1, the battery assembly 110 is in a charging state; if the voltage on the left side of the first resistor R1 is lower than the voltage on the right side of the first resistor R1, the battery assembly 110 is in a discharging state.

[0066] In a possible embodiment, the charge and discharge control circuit 150 is Q1, then one end of R1 is connected to the negative electrode of the battery assembly 110 and one end of R2, the other end of R22 is connected to the battery management chip 120, the other end of R1 is connected to the source of the NMOS tube Q1 and one end of R3, the other end of R3 is connected to the battery management chip 120, the gate of the NMOS tube Q1 is connected to the battery management chip 120, and the drain of the NMOS tube Q1 is connected to the negative charge and discharge port.

[0067] During charging, current flows through R1 to NMOS transistor Q1 and then to the negative charge / discharge port. During discharging, current flows through the negative charge / discharge port to NMOS transistor Q1 and then to R1. When the battery assembly 110 is discharging, the battery management chip 120 sends a high-level signal to turn on NMOS transistor Q1. When the battery management chip 120 detects that the voltage of a battery cell is lower than a preset first threshold or the total voltage of the battery assembly 110 is lower than a preset second threshold, for example, NMOS transistor Q1 may be disconnected to prevent overdischarge. When the battery assembly 110 is charging, if the battery management chip 120 detects that the total voltage of the battery assembly 110 is higher than a preset third threshold, for example, indicating that the battery assembly 110 is fully charged, NMOS transistor Q1 may be disconnected to prevent overcharging. The preset first threshold, the preset second threshold, and the preset third threshold can be selected based on actual circumstances. For example, the preset first threshold can be 3.3V; the preset second threshold can be 3.3V multiplied by the total number of battery cells; and the preset third threshold can be 4.3V multiplied by the total number of battery cells.

[0068] The present application provides a battery protection circuit for an electric power-assisted bicycle. The current sampling circuit can be composed of a first resistor, a second resistor, and a third resistor. The first resistor is connected between the charge and discharge control circuit and the negative electrode of the battery pack. The two ends of the first resistor are also connected to the power management chip through the second resistor and the third resistor, respectively. Thus, the present application can obtain the real-time current size of the battery pack during the charge and discharge process by collecting the current flowing through the first resistor. It is also possible to determine whether the battery pack is in a charging state or a discharging state by comparing the voltage sizes of the second resistor and the third resistor.

[0069] exist Figure 5 On this basis, the battery protection circuit of the electric-assisted bicycle provided in the embodiment of the present application is described below with reference to the accompanying drawings. Figure 6 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 5 .like Figure 6 As shown, the temperature sampling circuit 180 may include: a multi-channel sampling unit 181.

[0070] Among them, each sampling unit 181 is set at a preset position close to one or more battery cells in the battery assembly 110, so that each sampling unit 181 is close to one or more battery cells in the battery assembly 110 in physical space, and multiple sampling units 181 are connected to the power management chip 120 and the control unit 130, so that the power management chip 120 and the control unit 130 can detect the temperature changes of one or more battery cells in the battery assembly 110, thereby realizing the temperature collection of the battery assembly.

[0071] The present application provides a battery protection circuit for an electric-assisted bicycle. The temperature sampling circuit may include: multiple sampling units, each sampling unit is set at a preset position near one or more battery cells in the battery assembly, and the multiple sampling units are connected to the power management chip and the control unit. Therefore, the present application detects overheating problems during the charging and discharging process of the battery assembly by collecting the temperature of the battery assembly in real time, and after the above problem continues for a preset duration, the charge and discharge control circuit is broken down, and the fuse is controlled to melt, thereby realizing the detection of overheating problems by the battery protection circuit of the electric-assisted bicycle, ensuring the safety of the battery protection circuit of the electric-assisted bicycle, and improving the reliability of the battery protection circuit of the electric-assisted bicycle.

[0072] The following is an illustrative description of the battery protection circuit of the electric-assisted bicycle provided in the embodiments of the present application with reference to the accompanying drawings. Figure 7 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 6 .like Figure 7As shown, each sampling unit 181 may include a thermistor RT and a voltage divider resistor R.

[0073] One end of the voltage divider resistor R is used to receive a preset voltage signal. The voltage divider resistor R is connected to one end of the thermistor RT, and the other end of the thermistor RT is grounded. One end of the thermistor RT is connected to the power management chip 120 and the control unit 130, so that the control unit 130 and the power management chip 120 connected to the thermistor RT can detect the voltage on the thermistor RT. The resistance of the thermistor RT changes with temperature, and the resistance change of the thermistor RT corresponds to the temperature curve. In other words, the control unit 130 and the power management chip 120 can detect the voltage change on the thermistor RT, infer the resistance change of the thermistor RT, and then obtain the temperature change of the resistor component 110. The preset voltage signal can be selected according to actual conditions. For example, the preset voltage signal can be selected as 3.3V.

[0074] It should be noted that the thermistor RT is physically close to one or more battery cells in the battery assembly 110 .

[0075] The present application provides a battery protection circuit for an electric-assisted bicycle. Each sampling unit includes: a thermistor and a voltage-dividing resistor. One end of the voltage-dividing resistor is used to receive a preset voltage signal. The voltage-dividing resistor is connected to one end of the thermistor. The other end of the thermistor is grounded. One end of the thermistor is connected to a power management chip and a control unit. Thus, the present application detects overheating problems during the charging and discharging process of the battery assembly by real-time sampling of the temperature during the charging and discharging process of the battery assembly. If the above problem continues for a preset duration and the charge and discharge control circuit is broken down, the fuse is controlled to melt, thereby enabling the battery protection circuit of the electric-assisted bicycle to detect overheating problems, ensuring the safety of the battery protection circuit of the electric-assisted bicycle, and improving the reliability of the battery protection circuit of the electric-assisted bicycle.

[0076] exist Figure 4 On this basis, the battery protection circuit of the electric-assisted bicycle provided in the embodiment of the present application is described below with reference to the accompanying drawings. Figure 8 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 7 .like Figure 8 As shown, the battery protection circuit 100 may further include a DC step-down circuit 190 .

[0077] Among them, the input end of the DC step-down circuit 190 is connected to the positive pole of the battery assembly 110, the first output end of the DC step-down circuit 190 is connected to the fuse circuit 160, which is used to provide an electrical signal to the fuse circuit 160, and the second output end of the DC step-down circuit 190 is connected to the control unit 130, which is used for the control unit 130 to control the DC step-down circuit 190.

[0078] It should be noted that the above-mentioned preset voltage signal can be a preset voltage provided by the DC buck circuit 190, such as 3.3V. In one possible implementation, the first output end of the DC buck circuit 190 is further connected to one end of the voltage divider resistor R in each sampling unit 181 in the temperature sampling circuit 180, so as to provide a preset voltage signal (such as 3.3V) to the temperature sampling circuit 180.

[0079] This application provides a battery protection circuit for an electric-assisted bicycle. The battery protection circuit may further include a DC step-down circuit, wherein the DC step-down voltage input terminal is connected to the positive electrode of the battery assembly, the first output terminal of the DC step-down circuit is connected to the fuse circuit, and the second output terminal of the DC step-down circuit is connected to the control unit. Thus, this application can use the DC step-down circuit to provide a preset voltage signal to the battery protection circuit, thereby ensuring the safe operation of the battery protection circuit.

[0080] exist Figure 8 On this basis, the battery protection circuit of the electric-assisted bicycle provided in the embodiment of the present application is described below with reference to the accompanying drawings. Figure 9 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 8 .like Figure 9 As shown, the fuse circuit 160 may include a first switch unit 161 and a second switch unit 162 .

[0081] The first end of the first switch unit 161 is connected to the control unit 130 for receiving a fuse signal from the control unit 130. The second end of the first switch unit 161 is grounded. The third end of the first switch unit 161 is connected to the first end of the second switch unit 162. The second end of the second switch unit 162 is connected to the second output end of the DC step-down circuit 190, so that the DC step-down circuit 190 provides an operational electrical signal to the second switch unit 162. The third end of the second switch unit 162 is connected to a fuse for controlling the on / off of the fuse. In other words, the fuse circuit 160 can use the fuse signal from the control unit 130 to turn on the first switch unit 161, thereby turning on the second switch unit 162 and blowing the fuse.

[0082] The present application provides a battery protection circuit for an electric-assisted bicycle. The fuse circuit can be composed of a first switch unit and a second switch unit. The first end of the first switch unit is connected to the control unit, the second end of the first switch unit is grounded, the third end of the first switch unit is connected to the first end of the second switch unit, the second end of the second switch unit is connected to the second output end of the DC step-down circuit, and the third end of the second switch unit is connected to the fuse. Therefore, the present application can control the fuse to melt, thereby protecting the battery protection circuit of the electric-assisted bicycle from problems such as overtemperature, overcurrent, undervoltage, and overvoltage, thereby providing a second level of protection for the battery protection circuit of the electric-assisted bicycle and improving the reliability of the battery protection circuit of the electric-assisted bicycle.

[0083] The following is an illustrative description of the battery protection circuit of the electric-assisted bicycle provided in the embodiments of the present application with reference to the accompanying drawings. Figure 10 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 9 .like Figure 10 As shown, the first switch unit 161 may include: a first transistor Q2, a fourth resistor R4 and a fifth resistor R5.

[0084] Among them, the base of the first transistor Q2 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is the first end of the first switch unit 161, which is used to connect to the control unit 130 and obtain the fuse signal sent by the control unit 130. The base of the first transistor Q2 is connected to the emitter of the first transistor Q2 through the fifth resistor R5. The emitter of the first transistor Q2 is the second end of the first switch unit 161. The emitter of the first transistor Q2 is also grounded. The collector of the first transistor Q2 is the third end of the first switch unit 161.

[0085] The first transistor Q2 is used to be turned on or off according to the fuse signal of the control unit 130. The first transistor Q2 is an NPN transistor.

[0086] The present application provides a battery protection circuit for an electric-assisted bicycle, wherein the first switch unit is composed of a first transistor, a fourth resistor, and a fifth resistor. The base of the first transistor is connected to one end of the fourth resistor, and the other end of the fourth resistor is the first end of the first switch unit, which is used to connect to the control unit. The base of the first transistor is connected to the emitter of the first transistor through the fifth resistor. The emitter of the first transistor is the second end of the first switch unit, and the emitter of the first transistor is also grounded. The collector of the first transistor is the third end of the first switch unit. Therefore, the present application can control the conduction and disconnection of the fuse circuit through the first switch unit composed of the first transistor, the fourth resistor, and the fifth resistor, and then control the fuse, thereby ensuring the safety of the battery protection circuit of the electric-assisted bicycle and improving the reliability of the battery protection circuit of the electric-assisted bicycle.

[0087] The following is an illustrative description of the battery protection circuit of the electric-assisted bicycle provided in the embodiments of the present application with reference to the accompanying drawings. Figure 11 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 10 .like Figure 11 As shown, the second switch unit 162 may include: a second transistor Q3, a sixth resistor R6, a seventh resistor R7, a field effect transistor Q4, an eighth resistor R8 and a ninth resistor R9.

[0088] The base of the second transistor Q3 is connected to one end of the sixth resistor R6, the other end of the sixth resistor R6 is the first end of the second switch unit 162, and is used to connect to the third end of the first switch unit 161. The emitter of the second transistor Q3 is the second end of the second switch unit 162, and is used to connect to the second output end of the DC step-down circuit 190 to provide a preset operating voltage (e.g., 12V). The base of the second transistor Q3 is connected to the emitter of the second transistor Q3 via the seventh resistor R7. The collector of the second transistor Q3 is connected to the gate of the field-effect transistor Q4 via the eighth resistor R8. The drain of the field-effect transistor Q4 is the third end of the second switch unit 162, and is used to connect to the fuse. The drain of the field-effect transistor Q4 is connected to the source of the field-effect transistor Q4 via the ninth resistor R9. The source of the field-effect transistor Q4 is also grounded. The second transistor is a PNP-type transistor. The field-effect transistor Q4 is an NMOS transistor, and the field-effect transistor Q4 can be selected as an HG160N10LS field-effect transistor.

[0089] Thus, through Figure 11 The shown fusing circuit is used to convert the fusing signal from the control unit 130 into a switching on of the first transistor Q2, thereby switching on the second transistor Q3 and the field effect transistor Q4 to ground, thereby controlling the fusing of the fuse FUSE.

[0090] In a possible embodiment, the fusing circuit may further include a capacitor C1. Figure 12 A schematic diagram of the structure of a battery protection circuit for an electric assisted bicycle provided in an embodiment of the present application Figure 10 1. As Figure 12 As shown, one end of the capacitor C1 is connected to one end of the fourth resistor R4, and the other end of the capacitor C1 is grounded.

[0091] The present application provides a battery protection circuit for an electric-assisted bicycle, wherein the second switch unit is composed of a second transistor, a sixth resistor, a seventh resistor, a field-effect transistor, an eighth resistor and a ninth resistor. The base of the second transistor is connected to one end of the sixth resistor, and the other end of the sixth resistor is the first end of the second switch unit, which is used to connect to the third end of the first switch unit. The emitter of the second transistor is the second end of the second switch unit, which is used to connect to the second output end of the DC step-down circuit. The base of the second transistor is connected to the emitter of the second transistor through the sixth resistor, and the collector of the second transistor is connected to the gate of the field-effect transistor through the eighth resistor. The drain of the field-effect transistor is the third end of the second switch unit, which is used to connect to the fuse. The drain of the field-effect transistor is connected to the source of the field-effect transistor through the sixth resistor, and the source of the field-effect transistor is also grounded. Therefore, the present application can control the fuse through the fuse circuit composed of the second switching unit composed of the second transistor, the sixth resistor, the seventh resistor, the field effect transistor, the eighth resistor and the ninth resistor, and the first switching unit composed of the first transistor, the fourth resistor and the fifth resistor, thereby ensuring the safety of the battery protection circuit of the electric assisted bicycle and improving the reliability of the battery protection circuit of the electric assisted bicycle.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery protection circuit for an electric power-assisted bicycle, characterized in that: The battery protection circuit includes: a battery assembly, a power management chip, a control unit, a current sampling circuit, a charge and discharge control circuit, and a fuse circuit; Wherein, each battery cell in the battery assembly is respectively connected to the power management chip, the positive electrode of the battery assembly is connected to the positive charge and discharge interface through a fuse, and the negative electrode of the battery assembly is grounded; the negative electrode of the battery assembly is also connected to the negative charge and discharge interface through the charge and discharge control circuit, and the current sampling circuit is connected between the charge and discharge control circuit and the negative electrode of the battery assembly to detect the charge and discharge current of the battery assembly; The current sampling circuit is further connected to the power management chip, which is further connected to the charge and discharge control circuit, which is further connected to the control unit, which is connected to the fuse circuit, which is connected to the fuse; wherein the control unit is configured to receive an overvoltage signal of a preset duration from the power management chip or an overcurrent signal from the current sampling circuit to control the fuse to blow; The battery protection circuit further includes: a voltage detection circuit, which is connected to the positive electrode of the battery assembly to detect the charge and discharge voltage of the battery assembly, and is also connected to the control unit.

2. The battery protection circuit of the electric-assisted bicycle according to claim 1, characterized in that: The battery protection circuit further includes: a temperature sampling circuit, which is arranged at a preset position near the battery assembly to detect the temperature of the battery assembly, and the temperature sampling circuit is connected to the power management chip and the control unit; wherein the control unit is further configured to receive an overtemperature signal from the temperature sampling circuit for the preset duration to control the fuse to blow.

3. The battery protection circuit of the electric-assisted bicycle according to claim 1, characterized in that: The current sampling circuit includes: a first resistor, a second resistor and a third resistor. The first resistor is connected between the charge and discharge control circuit and the negative electrode of the battery assembly. The two ends of the first resistor are also connected to the power management chip through the second resistor and the third resistor respectively.

4. The battery protection circuit of the electric-assisted bicycle according to claim 2, characterized in that: The temperature sampling circuit includes: multiple sampling units, each sampling unit is arranged at a preset position close to one or more battery cells in the battery assembly, and the multiple sampling units are connected to the power management chip and the control unit.

5. The battery protection circuit of the electric-assisted bicycle according to claim 4, characterized in that: Each sampling unit includes: a thermistor and a voltage divider resistor, one end of the voltage divider resistor is used to receive a preset voltage signal, the voltage divider resistor is connected to one end of the thermistor, the other end of the thermistor is grounded, and one end of the thermistor is connected to the power management chip and the control unit.

6. The battery protection circuit of the electric-assisted bicycle according to claim 1, characterized in that: The battery protection circuit further includes: a DC step-down circuit, wherein an input end of the DC step-down circuit is connected to the positive electrode of the battery assembly, a first output end of the DC step-down circuit is connected to the fuse circuit, and a second output end of the DC step-down circuit is connected to the control unit.

7. The battery protection circuit of the electric-assisted bicycle according to claim 6, characterized in that: The fuse circuit includes: a first switch unit and a second switch unit, the first end of the first switch unit is connected to the control unit, the second end of the first switch unit is grounded, the third end of the first switch unit is connected to the first end of the second switch unit, the second end of the second switch unit is connected to the second output end of the DC step-down circuit, and the third end of the second switch unit is connected to the fuse.

8. The battery protection circuit of the electric-assisted bicycle according to claim 7, characterized in that: The first switch unit includes: a first transistor, a fourth resistor and a fifth resistor, the base of the first transistor is connected to one end of the fourth resistor, the other end of the fourth resistor is the first end of the first switch unit, and is used to connect to the control unit, the base of the first transistor is connected to the emitter of the first transistor through the fifth resistor, the emitter of the first transistor is the second end of the first switch unit, the emitter of the first transistor is also grounded, and the collector of the first transistor is the third end of the first switch unit.

9. The battery protection circuit of the electric-assisted bicycle according to claim 7, characterized in that: The second switch unit includes: a second transistor, a sixth resistor, a seventh resistor, a field-effect transistor, an eighth resistor and a ninth resistor. The base of the second transistor is connected to one end of the sixth resistor, the other end of the sixth resistor is the first end of the second switch unit, and is used to be connected to the third end of the first switch unit. The emitter of the second transistor is the second end of the second switch unit, and is used to be connected to the second output end of the DC step-down circuit. The base of the second transistor is connected to the emitter of the second transistor through the seventh resistor, the collector of the second transistor is connected to the gate of the field-effect transistor through the eighth resistor, the drain of the field-effect transistor is the third end of the second switch unit, and is used to be connected to the fuse. The drain of the field-effect transistor is connected to the source of the field-effect transistor through the ninth resistor, and the source of the field-effect transistor is also grounded.

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