Control system of multi-module lithium battery pack series protection board

Abstract

The invention discloses a control system of a multi-module lithium battery pack series protection board, which comprises a plurality of lithium battery modules, and the plurality of lithium battery modules are internally provided with protection boards for detecting voltage signals and temperature signals of the lithium battery modules; the protection board comprises a detection IC unit, a voltage detection unit and a temperature detection unit, and high-value components such as a charge-discharge MOS tube and a protection IC are placed in a charge-discharge control module, namely a mainboard. Other sampling resistors and detection ICs are designed in a protection board, namely a slave board. A control mode of one main board and a plurality of slave boards is used, and the number of electrical components on the slave boards is extremely small. Compared with a traditional lithium battery protection board in which the IC, the MOS and the auxiliary elements are all arranged, the overall cost is reduced. Battery pack serial numbers do not need to be distinguished, batched installation in any sequence can be achieved, and standard module design of the lithium battery pack can be achieved to be matched with the market.

Description

Technical Field

[0001] This invention relates to the field of lithium battery pack protection board technology, specifically a control system for a multi-module lithium battery pack series protection board. Background Technology

[0002] With the advancement of national standards and the development of lithium battery technology, the demand for lightweight, high-capacity, and long-cycle electric vehicles is increasing, and more and more vehicle manufacturers are starting to use lithium batteries to replace lead-acid batteries. However, certain drawbacks still exist.

[0003] 1. Lithium batteries require protection boards. Multiple lithium batteries connected in series require multiple protection boards. Traditionally, each protection board contains an IC, MOSFET, and auxiliary components, resulting in high costs. Figure 4 As shown. For example, a 60V20Ah electric bicycle would require five 12V20Ah lithium battery packs connected in series, which would also require five protection boards, increasing the overall cost.

[0004] 2. When multiple lithium batteries are connected in series using a single protection board, it is necessary to distinguish between master and slave battery packs. The slave battery pack does not contain a protection board, but it needs to have its wiring harness connected to the master battery pack. Figure 5 As shown. Overall, the wiring harness connections are complex. The differentiation of active battery packs increases manufacturing and installation costs, and the complex wiring harness connections can also lead to safety issues. For example, a 60V 20Ah electric vehicle uses five 12V 20Ah lithium battery packs connected in series. There is a protection board. The manufacturing and installation of battery packs 1, 2, 3, 4, and 5 are different, and there are many wiring harnesses to collect.

[0005] 3. Using a single battery pack design, limited by size and space, makes standardization impossible. For example, a 60V 20Ah electric scooter uses a single 60V 20Ah lithium battery pack placed in the battery compartment, which is too specific and cannot be matched with the entire market.

[0006] To address this, a control system for a multi-module lithium battery pack series protection board is proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a control system for a multi-module lithium battery pack series protection board to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a control system for a series protection board of a multi-module lithium battery pack, comprising multiple lithium battery modules, wherein each of the multiple lithium battery modules is equipped with a protection board for detecting the voltage signal and temperature signal of the lithium battery module;

[0009] The protection board includes a detection IC unit, a voltage detection unit, and a temperature detection unit. The voltage detection unit and the temperature detection unit are respectively connected to the detection IC unit and are used to detect the voltage signal and temperature signal of the lithium battery module.

[0010] A charge-discharge control module is connected in series on multiple lithium battery modules. The charge-discharge control module is connected to multiple protection boards through cascaded signal lines. The multiple protection boards can transmit the collected status signals of each lithium battery module to the charge-discharge control module for overall management.

[0011] The charge / discharge control module includes a protection IC and logic circuit unit, a discharge control MOSFET and a charge control MOSFET. The discharge control MOSFET and the charge control MOSFET are connected to the protection IC and logic circuit unit and are used to perform on / off switching according to instructions.

[0012] Preferably, the protection board further includes an equalization interface; the equalization interface is connected between the voltage detection unit and the lithium battery module to ensure that the voltage difference between individual cells is controlled within a range, thereby achieving balanced charging.

[0013] Preferably, the protection board further includes a fault indication unit, a communication transmission unit 1, and a heating control unit;

[0014] The fault indication unit is connected to the detection IC unit and is used to issue a fault warning signal when the corresponding lithium battery module is detected to have abnormal voltage or temperature.

[0015] The communication transmission unit 1 is connected to the detection IC unit and is used to transmit the status signals of the corresponding lithium battery modules collected by each protection board to the charge and discharge control module, and to transmit the control signals of the charge and discharge control module to each protection board.

[0016] The heating control unit is connected to the detection IC unit and is used to start the heating action when the temperature of the lithium battery module is lower than the set lower limit value.

[0017] Preferably, the charge / discharge control module further includes a current detection unit and a communication transmission unit 2;

[0018] The current detection unit is connected to the protection IC and logic circuit unit and is used to detect the current of the lithium battery module.

[0019] The communication transmission unit 2 is connected to the protection IC and logic circuit unit. The communication transmission unit 2 is used to connect with the communication transmission unit 1 on the protection board to realize signal transmission.

[0020] Preferably, the charging and discharging control module further includes a wireless transmission unit and a wired transmission unit;

[0021] The wireless transmission unit is connected to the protection IC and logic circuit unit, and is used to wirelessly transmit the received status signal to an external terminal to realize real-time data monitoring.

[0022] The wired transmission unit is connected to the protection IC and logic circuit unit, and is used to transmit the received status signal to the external terminal via wired transmission to realize real-time data monitoring.

[0023] Preferably, the charging and discharging control module is also connected to a display screen and a motor controller junction box.

[0024] Compared with existing technologies, the advantages of this invention are: high-value components such as charging / discharging MOSFETs and protection ICs are placed in the charging / discharging control module, i.e., the main board. Other sampling resistors and detection ICs are designed in the protection board, i.e., the slave board. Using a control method with one main board and multiple slave boards, the number of electrical components on the slave boards is minimal. Compared to traditional lithium battery protection boards where ICs, MOSFETs, and auxiliary components are all within a single protection board, the overall cost is reduced. Furthermore, it eliminates the need to distinguish battery pack serial numbers, allowing for batch production and installation in any order, enabling standardized modular design of lithium battery packs to meet market demands. Attached Figure Description

[0025] Figure 1 This is a system diagram of the present invention;

[0026] Figure 2 This is a schematic diagram of the protective plate of the present invention;

[0027] Figure 3 This is a schematic diagram of the charge / discharge control module of the present invention;

[0028] Figure 4 This is a schematic diagram of a traditional single protection plate;

[0029] Figure 5 This is a schematic diagram of a traditional series connection of multiple lithium batteries. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0031] Please see Figure 1-3 The present invention provides a technical solution: a control system for a series protection board of a multi-module lithium battery pack, comprising multiple lithium battery modules, each of which is equipped with a protection board, which is used to detect the voltage and temperature signals of the lithium battery modules in real time.

[0032] The protection board includes a detection IC unit, a voltage detection unit, and a temperature detection unit. The voltage detection unit is connected to the detection IC unit and its function is to continuously capture the voltage changes of the lithium battery module during charging and discharging, convert the voltage data into electrical signals and transmit them to the detection IC unit, so that the detection IC unit can quickly determine whether the module is in an overvoltage or undervoltage state.

[0033] The temperature detection unit is also connected to the detection IC unit, which can sense the operating temperature of the lithium battery module in real time. When the temperature is too high or too low, the temperature signal is fed back to the detection IC unit in a timely manner to provide temperature basis for subsequent protection actions.

[0034] A charge / discharge control module is connected in series with multiple lithium battery modules. The core function of this module is to centrally manage and coordinate the charging and discharging process of the entire series-connected lithium battery pack. The charge / discharge control module is connected to multiple protection boards via cascaded signal lines. This connection method enables efficient bidirectional signal transmission. On one hand, the multiple protection boards can collect and transmit the voltage, temperature, and other status signals of each lithium battery module to the charge / discharge control module, allowing the charge / discharge control module to have a comprehensive understanding of the entire battery pack's operating status. On the other hand, the charge / discharge control module can issue adjustment commands to each protection board based on the overall status analysis results, achieving targeted control of individual modules.

[0035] The charge and discharge control module includes a protection IC and logic circuit unit, a discharge control MOSFET, and a charge control MOSFET. The protection IC and logic circuit unit can perform logical analysis and judgment on the received status signals of each module. For example, when an overvoltage is detected in a certain module and the overall battery pack is about to be fully charged, a command to stop charging will be generated.

[0036] The discharge control MOSFET and the charge control MOSFET are connected to the protection IC and logic circuit unit. As actuators, they can precisely execute on / off actions according to the instructions issued by the protection IC and logic circuit unit. If overcharging is a risk during charging, the charge control MOSFET disconnects to cut off the charging circuit. If overcurrent or over-discharge occurs during discharging, the discharge control MOSFET disconnects to cut off the discharge circuit, thereby effectively protecting the lithium battery pack from overcharging, over-discharging, and overcurrent problems, while ensuring the safe operation of electrical equipment.

[0037] The protection board also includes an equalization interface, which connects the voltage detection unit and the lithium battery module. Its core function is to resolve voltage imbalance issues when multiple lithium battery modules are connected in series. Voltage differences can easily occur between the individual lithium battery modules or individual cells within a module. Without intervention, this can lead to some batteries being overcharged and others undercharged, thus shortening the overall battery pack's lifespan and even posing safety hazards. The equalization interface, based on voltage data from the voltage detection unit, supplements charging for cells with lower voltages and appropriately limits the charging current for cells with higher voltages. This controls the voltage differences between individual cells within a reasonable range, ultimately achieving balanced charging. This ensures that each battery is in its optimal charge / discharge state, improving the overall battery pack's capacity utilization and cycle life.

[0038] The protection board also includes a fault indication unit, a communication transmission unit 1, and a heating control unit. The fault indication unit is connected to the detection IC unit. Its function is to send out a fault warning signal in a visual manner, such as flashing lights or changing indicator light colors, when the detection IC unit detects an abnormal voltage or temperature in the corresponding lithium battery module. This eliminates the need for external terminals, allowing on-site operators or maintenance personnel to quickly identify the problematic lithium battery module, shortening troubleshooting time, preventing the abnormal state from escalating and causing the entire battery pack to fail, and improving maintenance efficiency and safety.

[0039] Communication transmission unit 1 is connected to the detection IC unit and undertakes bidirectional signal transmission. On the one hand, it can stably transmit the lithium battery module status signal integrated by the detection IC unit to the charge / discharge control module, ensuring that the charge / discharge control module can accurately monitor the operation of individual modules in real time. On the other hand, it can receive control commands issued by the charge / discharge control module and transmit the commands to the detection IC unit, which then controls the corresponding unit on the protection board to execute actions. This enables the charge / discharge control module to remotely regulate individual lithium battery modules, ensuring the coordination of the entire control system.

[0040] The heating control unit is connected to the detection IC unit. When the detection IC unit learns from the temperature detection unit that the temperature of the lithium battery module is lower than the set lower limit, the heating control unit will start the heating action under the control of the detection IC unit to provide a suitable working temperature for the lithium battery module and restore the normal charging and discharging performance of the battery.

[0041] The charge / discharge control module also includes a current detection unit, which is connected to the protection IC and logic circuit unit. Its core function is to monitor the current changes in the entire lithium battery pack's charge / discharge circuit in real time. The current detection unit converts the detected current signal into an electrical signal and transmits it to the protection IC and logic circuit unit. The protection IC and logic circuit unit compare the actual current with a preset safe current range. If the current exceeds the safe threshold, it immediately issues a command to control the discharge control MOSFET or the charging control MOSFET to disconnect the circuit, cutting off the abnormal current and protecting the lithium battery pack and electrical equipment from overcurrent problems.

[0042] The charge / discharge control module also includes a communication transmission unit 2, a wireless transmission unit, and a wired transmission unit. The communication transmission unit 2 is connected to the protection IC and logic circuit unit, and its function is to specifically adapt to the communication transmission unit 1 on the protection board, establishing a stable signal transmission channel between the two.

[0043] The wireless transmission unit connects to the protection IC and logic circuit unit. Its function is to enable wireless data transmission, wirelessly transmitting the overall battery pack status information processed by the protection IC and logic circuit unit to external terminals such as mobile phones, tablets, and computers. This wireless transmission method eliminates the need for on-site wiring, allowing operators to remotely monitor the battery pack's operating status in real time within a certain range.

[0044] The wired transmission unit connects to the protection IC and logic circuit unit, providing a wired data transmission channel. Compared to wireless transmission, wired transmission offers advantages such as strong resistance to electromagnetic interference, stable signal transmission, and low latency. This unit can accurately and stably transmit battery pack status signals to external terminals, such as vehicle dashboards, ensuring the reliability of data monitoring.

[0045] Working principle: The voltage detection unit of the protection board (slave board) collects the voltage signal of the corresponding lithium battery module in real time, and the temperature detection unit collects the temperature signal of the lithium battery module in real time. The collected voltage and temperature signals are transmitted to the detection IC unit of the slave board respectively. After preliminary processing of the received raw voltage and temperature signals, the detection IC unit establishes a matching signal channel with the communication transmission unit 2 of the charge and discharge control module (main board) through the communication transmission unit 1 of the slave board, and transmits the processed lithium battery module status signal to the main board.

[0046] The motherboard's communication transmission unit 2 receives the lithium battery module status signal from the board and transmits it to the motherboard's protection IC and logic circuit unit. The motherboard's current detection unit collects the current signal of the entire series-connected lithium battery pack's charging and discharging circuit in real time and also transmits it to the protection IC and logic circuit unit, achieving centralized acquisition of multi-dimensional signals of battery pack voltage, temperature, and current. The protection IC and logic circuit unit performs comprehensive logical analysis on the received voltage, temperature, and current signals, comparing the actual parameters with preset safety thresholds to determine whether the lithium battery pack is in a normal charging and discharging state, or whether there are abnormal risks such as overcharging, undercharging, overheating, or overcurrent.

[0047] If the protection IC and logic circuit unit determine that there is no abnormality, the discharge control MOSFET and charge control MOSFET remain in the on state to ensure the normal operation of the charging and discharging circuit. If an abnormality is detected, a disconnect command is immediately issued to the corresponding MOSFET. In the case of overcharging, the charge control MOSFET is disconnected to cut off the charging circuit. In the case of over-discharging or overcurrent, the discharge control MOSFET is disconnected to cut off the discharge circuit, thereby achieving real-time protection of the lithium battery pack and avoiding problems caused to the battery pack by abnormal conditions.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control system for a multi-module lithium battery pack series protection board, comprising multiple lithium battery modules, characterized in that: A plurality of the lithium battery modules are provided with protection boards for detecting voltage signals and temperature signals of the lithium battery modules; The protection board comprises a detection IC unit, a voltage detection unit and a temperature detection unit, wherein the voltage detection unit and the temperature detection unit are connected with the detection IC unit, and are used for detecting voltage signals and temperature signals of the lithium battery modules; A plurality of the lithium battery modules are provided with charge-discharge control modules in series, and the charge-discharge control modules are connected with the plurality of protection boards through cascade signal lines, so that the plurality of protection boards can transmit the collected state signals of the lithium battery modules to the charge-discharge control module for overall management. The charge-discharge control module comprises a protection IC and a logic circuit unit, a discharge control MOS tube and a charge control MOS tube, wherein the discharge control MOS tube and the charge control MOS tube are connected with the protection IC and the logic circuit unit, and are used for executing on-off according to instructions.

2. The control system of a multi-module lithium battery pack series protection board according to claim 1, characterized in that: The protection board further comprises an equalization interface; The equalization interface is connected between the voltage detection unit and the lithium battery module, and is used for ensuring that the voltage difference between the single batteries is controlled within a range, so as to realize equalization charging.

3. The control system of a multi-module lithium battery pack series protection board according to claim 1, characterized in that: The protection board further comprises a fault indication unit, a communication transmission unit 1 and a heating control unit; The fault indication unit is connected with the detection IC unit, and is used for issuing a fault warning signal when detecting voltage abnormalities or temperature abnormalities of the corresponding lithium battery module; The communication transmission unit 1 is connected with the detection IC unit, and is used for transmitting the state signals of the corresponding lithium battery module collected by each protection board to the charge-discharge control module, and transmitting the control signals of the charge-discharge control module to each protection board; The heating control unit is connected with the detection IC unit, and is used for starting a heating action when the temperature of the lithium battery module is lower than a set lower limit value.

4. The control system of a multi-module lithium battery pack series protection board according to claim 3, characterized in that: The charge-discharge control module further comprises a current detection unit and a communication transmission unit 2; The current detection unit is connected with the protection IC and the logic circuit unit, and is used for detecting the current of the lithium battery module; The communication transmission unit 2 is connected with the protection IC and the logic circuit unit, and is used for being connected with the communication transmission unit 1 on the protection board to realize signal transmission.

5. The control system of a multi-module lithium battery pack series protection board according to claim 1, characterized in that: The charge-discharge control module further comprises a wireless transmission unit and a wired transmission unit; The wireless transmission unit is connected with the protection IC and the logic circuit unit, and is used for wirelessly transmitting the received state signals to an external terminal to realize real-time monitoring of data; The wired transmission unit is connected with the protection IC and the logic circuit unit, and is used for wirelessly transmitting the received state signals to an external terminal to realize real-time monitoring of data.

6. The control system of a multi-module lithium battery pack series protection board according to claim 1, characterized in that: The charge-discharge control module is further connected with a display screen and a motor controller junction box.

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