Relay protection circuit of BMS
By designing a simplified BMS relay protection circuit and controlling the relay using current detection signal, the problem of high manufacturing cost and assembly failure rate caused by multi-relay technology in the battery management system is solved, and lower manufacturing cost and higher Product stability.
Patent Information
- Application Number
- CN202420812784.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-16
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-04-16
AI Technical Summary
Multi-relay technology in existing battery management systems (BMS) results in excessive manufacturing costs and high assembly failure rates, increasing production complexity and possibility of errors.
A relay protection circuit for BMS was designed, and by adjusting multiple relays into one, using BMS battery, shunt, current detection module, AFE chip, MCU control chip, pre-load MOS module, pre-charge MOS module, relay and relay Control the power supply and control the opening and closing state of the relay using the current detection signal, reducing the standby current and reducing manufacturing costs.
It reduces manufacturing costs, simplifies production processes, reduces standby current, improves product stability and sustainability, and solves the problems of high manufacturing costs and assembly defect rate of multi-relay technology.
Smart Images
Figure CN222147152U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of relay protection, in particular to a relay protection circuit of a BMS. Background Art
[0002] Current battery management systems (BMS) use a complex relay scheme that includes four key relays: pre-charge relay, pre-discharge relay, main charge relay, and main discharge relay. These relays play an important role in the battery charging and discharging process, helping to manage the flow of current and protecting the battery from over-charging and over-discharging.
[0003] However, while this relay solution is very effective in terms of functionality, it also introduces a series of problems. The existing solution increases the complexity of battery assembly. Each relay needs to be precisely installed and matched with other components, which requires more manual operations and more time for debugging and testing. This not only increases the workload of the production line, but also increases the possibility of errors in the manufacturing process. The existing solution significantly increases the manufacturing cost. In addition to the cost of the relay itself, it is also necessary to consider the increased labor costs, additional equipment and tooling investments, and the space costs occupied by the relay. The relay solution also increases the defect rate. Since there are more components and connections involved, the possibility of errors in the manufacturing process also increases accordingly. This may cause some batteries to fail or have quality problems during the production process, requiring additional repairs or recycling, which increases unnecessary costs and time costs. Therefore, in order to solve the technical problems of the current multi-relay technology with excessively high manufacturing costs and high assembly defect rates, a new technology is needed to solve the current problems. Utility Model Content
[0004] The main purpose of the utility model is to solve the technical problems of the current multi-relay technology that the manufacturing cost is too high and the assembly defect rate is too high.
[0005] The utility model provides a relay protection circuit of a BMS in a first aspect, and the relay protection circuit of the BMS comprises: a BMS battery, a shunt, a current detection module, an AFE chip, an MCU control chip, a pre-discharge MOS module, a pre-charge MOS module, a relay, and a relay control power supply, wherein the positive electrode of the BMS battery is connected to the negative electrode of an external load, the negative electrode of the BMS battery is connected to one end of the shunt, the other end of the shunt is connected to the pre-discharge MOS module and the relay, the relay is connected to the positive electrode of the external load, the relay control power supply is connected in parallel with the relay, the pre-discharge MOS module is connected in series with the pre-charge MOS module, the pre-discharge MOS module and the pre-charge MOS module are connected in parallel with the relay, the shunt is connected in parallel with the current detection module, the current detection module is connected to the AFE chip, the AFE chip is connected to the MCU control chip, and the MCU control chip is connected to the relay control power supply;
[0006] Among them, the current detection module is used to detect the current of the shunt to generate a current detection signal, and the current detection signal is transmitted to the AFE chip to determine whether the detection current exceeds the current threshold; when the detection current exceeds the current threshold, the AFE chip sends a notification signal to the MCU control chip, and the MCU control chip controls the opening and closing state of the relay control power supply based on the notification signal, so as to control the opening and closing state of the relay.
[0007] Optionally, in a first implementation of the first aspect of the utility model, the relay protection circuit of the BMS further includes: a resettable fuse, one end of which is connected in series with the pre-charge MOS module.
[0008] Optionally, in a second implementation of the first aspect of the utility model, the relay protection circuit of the BMS further includes: a pre-charge and discharge current limiting resistor, one end of the pre-charge and discharge current limiting resistor being connected in series with the other end of the resettable fuse.
[0009] Optionally, in a third implementation of the first aspect of the utility model, the relay protection circuit of the BMS further includes: a pre-discharge unidirectional current limiting resistor, one end of the pre-discharge unidirectional current limiting resistor being connected in series with the other end of the pre-charge current limiting resistor.
[0010] Optionally, in a fourth implementation of the first aspect of the utility model, the other end of the pre-discharge unidirectional current limiting resistor is connected to the positive electrode of the external load.
[0011] Optionally, in a fifth implementation of the first aspect of the utility model, the pre-discharge MOS module includes: a first MOS tube and a first diode, the source of the first MOS tube is connected to the cathode of the first diode, the drain of the first MOS tube is connected to the anode of the first diode, and the drain of the first MOS tube and the anode of the first diode are connected to the pre-charge MOS module.
[0012] Optionally, in a sixth implementation of the first aspect of the utility model, the pre-charge MOS module includes: a second MOS tube and a second diode, the source of the second MOS tube is connected to the cathode of the second diode, the drain of the second MOS tube is connected to the anode of the second diode, and the drain of the first MOS tube is connected to the drain of the second MOS tube.
[0013] Optionally, in a seventh implementation of the first aspect of the utility model, the pre-amplifier MOS module further includes: a first capacitor, and the first capacitor is connected in parallel with the first MOS tube.
[0014] Optionally, in an eighth implementation of the first aspect of the utility model, the pre-charge MOS module includes: a second capacitor, and the second capacitor is connected in parallel with the second MOS tube.
[0015] Optionally, in a ninth implementation of the first aspect of the utility model, the relay control power supply includes: a 12V DC power supply.
[0016] In the embodiment of the utility model, by modifying the circuit, multiple relays are adjusted to one, which not only reduces the manufacturing cost and facilitates the production and assembly process, but also reduces the standby current, ensures the stability and sustainability of the product, and solves the technical problems of the current multi-relay technology of excessively high manufacturing cost and excessively high assembly defective rate. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a schematic diagram of a first embodiment of a relay protection circuit of a BMS in an embodiment of the utility model;
[0018] Figure 2 Schematic diagram of a second embodiment of the relay protection circuit of the BMS in the embodiment of the utility model. DETAILED DESCRIPTION
[0019] An embodiment of the utility model provides a relay protection circuit for a BMS.
[0020] The following will describe the embodiments of the present invention in more detail with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.
[0021] In the description of the embodiments disclosed in the present utility model, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.
[0022] For ease of understanding, the specific process of the embodiment of the utility model is described below. Figure 1 , an embodiment of the relay protection circuit of the BMS in the embodiment of the utility model, the relay protection circuit of the BMS includes: a BMS battery 22, a shunt 10, a current detection module 11, an AFE chip 19, an MCU control chip 20, a pre-discharge MOS module 12, a pre-charge MOS module 15, a relay 13, and a relay control power supply 14, the positive electrode of the BMS battery 22 is connected to the external load negative electrode 211, that is, the positive electrode of the battery cell is used as the battery output positive electrode 211, the negative electrode of the BMS battery 22 is connected to one end of the shunt 10, and the other end of the shunt 10 is connected to the pre-discharge MOS module 12, the pre-charge MOS module 15, the relay 13, and the relay control power supply 14. The pre-discharge MOS module 12 and the relay 13 are connected to the positive pole of the external load, the relay control power supply 14 is connected in parallel with the relay 10, the pre-discharge MOS module 12 is connected in series with the pre-charge MOS module 15, the pre-discharge MOS module 12 and the pre-charge MOS module 15 are connected in parallel to the relay 13, the shunt 10 is connected in parallel to the current detection module 11, the current detection module 11 is connected to the AFE chip 19, the AFE chip 19 is connected to the MCU control chip 20, and the MCU control chip 20 is connected to the relay control power supply 14;
[0023] The current detection module 11 is used to detect the current of the shunt 10 to generate a current detection signal, and the current detection signal is transmitted to the AFE chip 19 to determine whether the detection current exceeds the current threshold;
[0024] When the detected current exceeds the current threshold, the AFE chip 19 sends a notification signal to the MCU control chip 20 , and the MCU control chip 20 controls the on / off state of the relay control power supply 14 based on the notification signal, so as to control the on / off state of the relay 13 .
[0025] Specific explanation of the principle: the current detection module 11 is used for current collection. When the current passes through the shunt 10, a voltage drop will be generated at both ends. When the current flows through the shunt 10 and generates a voltage drop, the voltage at both ends will be detected to the current detection module 11 to transmit the signal to the AFE chip 19 to make corresponding control to control the pre-discharge MOS module 12, the pre-charge MOS module 15, and the relay control power supply 14. The AFE chip 19 controls the opening and closing of the relay 13 according to the actual current, and the MCU control chip 20 obtains the current size from the AFE chip 19 and makes corresponding control output.
[0026] Furthermore, the relay protection circuit of the BMS further includes: a resettable fuse 16 , one end of which is connected in series with the pre-charge MOS module 15 .
[0027] The relay protection circuit of the BMS further includes: a pre-charge and discharge current limiting resistor 17 , one end of which is connected in series with the other end of the resettable fuse 16 .
[0028] The relay protection circuit of the BMS further includes: a pre-discharge unidirectional current limiting resistor 18 , one end of which is connected in series with the other end of the pre-charge and discharge current limiting resistor 17 .
[0029] The other end of the pre-discharge unidirectional current limiting resistor 18 is connected to the external load positive electrode 212 .
[0030] The resettable fuse 16 controls the switch of the current. When the current is greater than the designed pre-discharge current, the resettable fuse 19 will automatically disconnect, opening the relay 13, the pre-charge and discharge current limiting resistor 17, and the pre-discharge unidirectional current limiting resistor 18. When the load and charging current pass through the pre-charge and discharge current limiting resistor 17 and the pre-discharge unidirectional current limiting resistor 18, the current limiting resistor plays a current limiting role.
[0031] For details, please refer to Figure 2 , Figure 2 This is a schematic diagram of a specific embodiment of an embodiment of the utility model, wherein the pre-discharge MOS module comprises: a first MOS tube M1 and a first diode D1, wherein the source of the first MOS tube M1 is connected to the cathode of the first diode D1, the drain of the first MOS tube M1 is connected to the anode of the first diode D1, and the drain of the first MOS tube M1 and the anode of the first diode D1 are connected to the pre-charge MOS module.
[0032] The pre-amplifier MOS module further includes: a first capacitor (C102 or C101), the first capacitor (C102 or C101) is connected in parallel with the first MOS transistor M1, and is actually also connected in parallel with the first diode D1.
[0033] The pre-charge MOS module includes: a second MOS tube M2 and a second diode D2, wherein the source of the second MOS tube M2 is connected to the cathode of the second diode D2, the drain of the second MOS tube M2 is connected to the anode of the second diode D2, and the drain of the first MOS tube M1 is connected to the drain of the second MOS tube M2.
[0034] The pre-charge MOS module includes: a second capacitor (C99 or C100), and the second capacitor (C99 or C100) is connected in parallel with the second MOS transistor M2.
[0035] The relay control power supply 14 may be a 12V DC power supply.
[0036] Although Figure 2 The first MOS tube M1 and the second MOS tube M2 in the embodiment have parasitic diodes, but in fact, MOS tubes without parasitic diodes can be used to implement the solution of the present application.
[0037] Discharge control principle: When the load needs to be discharged, under normal circumstances, the pre-charge MOS module 15 and the pre-discharge MOS tube 15 are both turned on, and the relay 13 is in the disconnected state, so that the standby current is about 10 times smaller (such as the standby current of the pre-charge and pre-discharge relays can reach more than 100mA, and the standby current of the present application is about 10mA.) Once the external load is connected, the current will pass through the pre-discharge unidirectional current limiting resistor 18, the pre-charge and discharge current limiting resistor 17, the self-resetting fuse 16, the pre-charge MOS module 15, and the pre-discharge MOS module 12, and there will be current on the shunt 10. When the AFE chip 19 detects a current greater than 1A, it will transmit a signal to notify the MCU control chip 20 to control the relay control power supply 14 to turn on the relay 13. At this time, the relay 13 module works normally, and the load passes through the relay 13 with a large current.
[0038] Charging control principle: When the charger is plugged in for charging, under normal circumstances, the pre-charge MOS module 15 and the pre-discharge MOS tube 15 are both turned on, and the relay 13 is in the disconnected state. When the charger is plugged in for charging, the current of the charger will pass through the positive pole to the negative pole of the battery cell, and the current will pass through the bypass diode of the shunt 10, the pre-discharge MOS module 12, the pre-charge MOS module 15, the self-recovery fuse 16, the pre-charge and discharge current limiting resistor 17, and the pre-discharge unidirectional current limiting resistor 18 to the output negative pole of the battery. There will be current on the shunt 10, and the AFE chip 19 detects a current greater than 500mA. It will notify the MCU control chip 20 to control the relay control power supply 14 to turn on the relay 13. At this time, the relay 13 works normally, and the load is charged with a large current through the relay 13.
[0039] In addition, although each operation is described in a specific order, this should be understood as requiring such operation to be performed in the specific order shown or in a sequential order, or requiring that all illustrated operations should be performed to obtain desired results. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present disclosure. Some features described in the context of a separate embodiment can also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation can also be implemented in multiple implementations individually or in any suitable sub-combination mode.
[0040] Although the subject matter has been described in language specific to structural features and / or methodological logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims.
Claims
1. A relay protection circuit for a BMS, characterized in that: The relay protection circuit of the BMS includes: a BMS battery, a shunt, a current detection module, an AFE chip, an MCU control chip, a pre-discharge MOS module, a pre-charge MOS module, a relay, and a relay control power supply. The positive electrode of the BMS battery is connected to the negative electrode of the external load, the negative electrode of the BMS battery is connected to one end of the shunt, the other end of the shunt is connected to the pre-discharge MOS module and the relay, the relay is connected to the positive electrode of the external load, the relay control power supply is connected in parallel with the relay, the pre-discharge MOS module is connected in series with the pre-charge MOS module, the pre-discharge MOS module and the pre-charge MOS module are connected in parallel with the relay, the shunt is connected in parallel with the current detection module, the current detection module is connected to the AFE chip, the AFE chip is connected to the MCU control chip, and the MCU control chip is connected to the relay control power supply; Among them, the current detection module is used to detect the current of the shunt to generate a current detection signal, and the current detection signal is transmitted to the AFE chip to determine whether the detection current exceeds the current threshold; when the detection current exceeds the current threshold, the AFE chip sends a notification signal to the MCU control chip, and the MCU control chip controls the opening and closing state of the relay control power supply based on the notification signal, so as to control the opening and closing state of the relay.
2. The relay protection circuit of the BMS according to claim 1, characterized in that: The relay protection circuit of the BMS further includes: a resettable fuse, one end of which is connected in series with the pre-charge MOS module.
3. The relay protection circuit of the BMS according to claim 2, characterized in that: The relay protection circuit of the BMS further includes: a pre-charge and discharge current limiting resistor, one end of which is connected in series with the other end of the resettable fuse.
4. The relay protection circuit of the BMS according to claim 3, characterized in that: The relay protection circuit of the BMS further includes: a pre-discharge unidirectional current limiting resistor, one end of which is connected in series with the other end of the pre-charge and discharge current limiting resistor.
5. The relay protection circuit of the BMS according to claim 4, characterized in that: The other end of the pre-discharge unidirectional current limiting resistor is connected to the positive electrode of the external load.
6. The relay protection circuit of the BMS according to claim 1, characterized in that: The pre-discharge MOS module includes: a first MOS tube and a first diode, the source of the first MOS tube is connected to the cathode of the first diode, the drain of the first MOS tube is connected to the anode of the first diode, and the drain of the first MOS tube and the anode of the first diode are connected to the pre-charge MOS module.
7. The relay protection circuit of the BMS according to claim 6, characterized in that: The pre-charge MOS module includes: a second MOS tube and a second diode, the source of the second MOS tube is connected to the cathode of the second diode, the drain of the second MOS tube is connected to the anode of the second diode, and the drain of the first MOS tube is connected to the drain of the second MOS tube.
8. The relay protection circuit of the BMS according to claim 6, characterized in that: The pre-amplifier MOS module further includes: a first capacitor, which is connected in parallel with the first MOS tube.
9. The relay protection circuit of the BMS according to claim 7, characterized in that: The pre-charge MOS module includes: a second capacitor, and the second capacitor is connected in parallel with the second MOS tube.
10. The relay protection circuit of the BMS according to claim 1, characterized in that: The relay control power supply includes: a 12V DC power supply.