Multi-path battery pack charging system based on RS485 bus

Abstract

The utility model relates to a battery charging technology, and aims to provide a charging system of a multipath battery pack based on an RS485 bus. The charging system comprises a master control display module, a plurality of AC-DC modules and a plurality of charging modules. Wherein the charging module comprises a main control chip, a 485 communication module, an internal power supply, a switching device and a plurality of charging sub-modules; a direct current input interface of the charging module is connected with a plurality of charging sub-modules through a switching device, and each charging sub-module is provided with a battery pack interface; each AC-DC module and a plurality of charging modules form a charging group, and the charging modules in the charging group are respectively connected to the output end of the AC-DC module and the 485 communication interface of the master control display module in parallel. The system is based on a grouping design and an intra-group multi-charging electronic module design, the performance of a main control chip can be maximized, the data exchange capacity of the system is reduced by fully utilizing communication protocol characteristics, the performance of a communication module is improved, the overall control efficiency is greatly improved, and safe and automatic charging of a small-power charging pack is realized.

Description

Technical Field

[0001] The utility model relates to battery charging technology, and particularly to a charging system for multiple battery packs based on the RS485 bus. Background Technique

[0002] Based on the requirement of maintaining the product life, the lithium battery pack assembly factory usually needs to charge the lithium battery to a suitable voltage before arranging shipment. Since the factory produces a large variety and quantity of battery packs, how to quickly, efficiently and batch charge different types of battery packs has always been a rather difficult problem.

[0003] According to the summary of actual production experience, when charging a large number of different types of battery packs, the charging system needs to meet the following conditions simultaneously:

[0004] (1) The charging voltage is adjustable. Generally, the factory requirement for the power of lithium batteries is around 60%-70%. For different types of battery packs, due to the different capacities and the number of series and parallel connections of the batteries, different charging voltages need to be set.

[0005] (2) The charging current is adjustable. If different-capacity batteries are charged with the same current, the small-capacity battery will have an excessive charging current, which will affect the battery life and even cause overheating and safety hazards; while for the large-capacity battery, the charging speed may be too slow, resulting in too long charging time and low efficiency. Therefore, it is necessary to be able to adjust the charging current to meet the charging requirements of different-capacity batteries.

[0006] (3) Large-scale charging can be carried out. Since the battery pack factory produces tens of thousands of pieces (only) at a time, a single set of charging system needs to be able to quickly charge at least several hundred battery packs at a time. When the factory configures several sets of systems, the need for large-scale production can be met.

[0007] (4) The charging system is modular. The charging module of the system should be able to charge dozens of battery packs at the same time and realize the monitoring of each charging module. The advantage of doing this is that the charging modules can be added or reduced at any time, which is convenient for large-scale and flexible deployment of the charging system. Whether it is a large factory or a small factory, the number of charging modules can be customized and expanded according to actual needs. At the same time, the modularization of the charging system is beneficial to improving the operation reliability. The failure of a single module will not spread to the entire system, which is beneficial to fault isolation and equipment maintenance, and will not cause the entire charging system to fail suddenly. When a failure occurs, as long as a single charging module is replaced and repaired, the problem can be solved.

[0008] (5) Centralized monitoring. The charging voltage, charging current, charging time, etc. of each charging module can be centrally set. Through the monitoring panel or the monitoring computer, the parameters of all charging modules of the system can be directly set without manual setting for each charging module, which can greatly improve the efficiency.

[0009] (6) It needs to have extremely high safety. Lithium batteries are products with relatively high energy density. If the safety awareness of operators is insufficient and improper handling occurs during use, storage and other links, lithium batteries will become "time bombs", easily triggering safety accidents such as fires and explosions, and once spontaneous combustion and explosion occur, it is difficult to extinguish, easily causing casualties. Therefore, the charging system of lithium batteries requires certain safety monitoring and disposal technical measures to prevent overcharging and overheating of lithium batteries. The charging module needs to monitor the charging voltage, current and temperature of the lithium battery. Once abnormalities are found, charging should be stopped immediately and a warning should be issued.

[0010] Currently, the lithium battery pack charging systems used in lithium battery pack assembly plants are usually of the following two types: One is composed of several independent charging modules. The characteristics of this charging system are low price, and multiple charging modules can be assembled through a cabinet; its disadvantage is that each charging module can only charge one battery pack, and each charging module needs to be set with charging parameters separately, and the voltage and current settings are achieved through adjustable resistors, and generally there is no temperature detection. The other is with a monitoring interface. The parameters of each charging module can be set through the monitoring interface, and the charging module can also report the charging information to the monitor through communication, but the price of this system is relatively expensive.

[0011] Judging from the records in currently published literature or the usage in actual production applications, there is no charging system that can simultaneously meet the requirements of simple operation, excellent performance and low cost. Therefore, if a new charging system solution can be proposed, it is very necessary for improving the efficiency and reducing the cost of lithium battery pack assembly production. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a charging system for multiple battery packs based on the RS485 bus.

[0013] To solve the above technical problem, the solution adopted by the present invention is:

[0014] Provide a charging system for multiple battery packs based on the RS485 bus. The charging system includes a main control display module, multiple AC-DC modules and several charging modules; wherein,

[0015] The main control and display module includes a human-computer interaction interface, a processor, a memory, a 485 communication chip, a main control power module, as well as a power sampling signal input interface, a relay output interface, and a 485 communication interface;

[0016] The input end of the AC-DC module is connected to the AC power grid through a relay, and the relay is connected to the relay output interface of the main control and display module through a signal line; the output end of the AC-DC module is connected to the power sampling signal input interface of the main control module through a signal line, and is used to collect the output voltage of the AD-DC power supply;

[0017] The charging module includes a main control chip, a 485 communication module, an internal power supply, switching devices, and multiple charging sub-modules; the charging module is provided with a DC input interface, and the DC input interface is connected to multiple charging sub-modules through switching devices; each charging sub-module is respectively provided with a battery pack interface and is respectively connected to the pins of the main control chip; the internal power supply is respectively connected to the main control chip and the 485 communication module through wires to supply power to both; the main control chip samples the voltage signal from the DC input interface and controls the input of each charging sub-module by controlling the on / off of the switching devices;

[0018] Each AC-DC module and multiple charging modules form a charging group, and the number of the power sampling signal input interface, the relay output interface, and the 485 communication interface in the main control and display module is at least equal to the number of charging groups; the charging modules within the same charging group are respectively connected to the output end of the AC-DC module in a parallel manner, and the input end of the AC-DC module is connected to the AC power grid, converting AC into DC and supplying power to the charging modules within the group; the charging modules within the same group are respectively connected to the 485 communication interface of the main control and display module in a parallel manner through signal lines.

[0019] As an improved solution, the main control and display module includes a housing, and the processor, the memory, the 485 communication chip, and the main control power module are all arranged inside the housing; the human-computer interaction interface and each interface are all arranged on the housing, and the main control power module is connected to the 220V AC power grid through an interface end and a cable.

[0020] As an improved solution, the main control and display module further includes redundantly provided power sampling signal input interfaces, relay output interfaces, and 485 communication interfaces.

[0021] As an improved solution, the human-computer interaction interface is a touch screen that is simultaneously used as a display and input interface, or a combination of an electronic display screen and a keyboard.

[0022] As an improved solution, the AC-DC module internally includes a rectifying and filtering circuit, a buck circuit, and a voltage stabilizing circuit; the input end of the AC-DC module is connected to 220V alternating current, and its output end provides a DC voltage.

[0023] As an improved solution, the DC input of the charging module comes from the DC power output of the AD-DC module; the internal power supply includes a 5V converted power supply and a 5V isolated power supply; the 5V converted power supply is connected by a DC input through a wire, and the 5V isolated power supply is a 5V-to-5V isolated small power supply for powering the isolated end of the 485 communication.

[0024] As an improved solution, in the charging module, the 485 communication module is respectively connected to a 485 communication interface and a main control chip.

[0025] As an improved solution, in the charging module, the main control chip is an MCU main control chip, and the charging sub-module is a constant voltage and constant current charging chip with a BUCK architecture; the switching device is a relay switch or a MOS tube switch.

[0026] As an improved solution, in the charging module, the battery pack interface includes a positive terminal, a negative terminal, and a temperature wire terminal.

[0027] As an improved solution, in the main control and display module, there is a wireless communication chip or a wired communication chip, and the main control and display module is connected to a server provided in the cloud through wireless or wired networking.

[0028] Compared with the prior art, the technical effects of the present utility model are as follows:

[0029] 1. In the multi-channel battery pack charging system of the present utility model, by forming a charging group with each AC-DC module and multiple charging modules, based on the grouped design and the design of multiple charging sub-modules in the charging module, the performance of the MCU main control chip can be maximized, and the characteristics of the RS-485 communication protocol can be fully utilized to reduce the data exchange volume and improve the performance of the communication module; therefore, the overall control efficiency of the system can be greatly improved.

[0030] 2. Compared with similar technologies or mature products in the prior art, the present utility model can achieve safe and automatic charging of small-power charging packs, and the product implementation method is simple and reliable; the price of the manufactured product has great advantages and can meet many product requirements of battery pack manufacturers. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a circuit structure schematic diagram of a battery pack charging system configured with multi-channel charging modules.

[0032] Figure 2Schematic diagram of the charging module circuit structure for a four-way battery pack. Detailed implementation

[0033] The following combines with the attached drawings to describe the detailed implementation of the present utility model.

[0034] The first part: Implementation solution of the present utility model

[0035] The charging system for multiple battery packs based on the RS485 bus provided by the present utility model mainly includes three parts: a main control display module, multiple AC-DC modules, and several charging modules. Among them:

[0036] 1. The main control display module includes a human-computer interaction interface, a processor, a memory, a 485 communication chip, a main control power module, as well as a power sampling signal input interface, a relay output interface, and a 485 communication interface;

[0037] As an optional solution, the main control display module includes a housing, and the processor, memory, 485 communication chip, and main control power module are all arranged inside the housing; the human-computer interaction interface and each interface are all arranged on the housing, and the main control power module is connected to the 220V AC power grid through the interface end and the cable. Or, the components of the main control display module except the human-computer interaction interface can also be implemented in a circuit board on-board manner, and multiple circuit boards are integrally installed in the same cabinet; the human-computer interaction interfaces of each main control power module are all installed on the surface of the cabinet, or the same human-computer interaction interface is used. The human-computer interaction interface can optionally be a touch screen that serves as both a display and an input interface, or a combination of an electronic display screen and a keyboard.

[0038] To facilitate capacity expansion, the main control display module further includes redundant power sampling signal input interfaces, relay output interfaces, and 485 communication interfaces. One or more charging groups can be conveniently connected when needed.

[0039] 2. The AC-DC module, its input end is connected to the AC power grid through a relay, and the relay is connected to the relay output interface of the main control display module through a signal line; the output end of the AC-DC module is connected to the power sampling signal input interface of the main control module through a signal line, and is used to collect the output voltage of the AD-DC power supply.

[0040] The AC-DC module internally includes a rectification and filtering circuit, a buck circuit, and a voltage stabilization circuit, and this part can be implemented according to the conventional prior art; the input end of the AC-DC module is connected to 220V alternating current, and its output end provides a direct current voltage. For example, when the voltage range of the battery pack is 3 - 21V, the output voltage of the AD-DC module can be set to 24V. If the voltage range of the end-user battery pack is different, an AD-DC module with a different output voltage can also be selected.

[0041] 3. The charging module includes a main control chip, a 485 communication module, an internal power supply, a switching device, and multiple charging sub-modules; the charging module is provided with a DC input interface, and the DC input interface is connected to multiple charging sub-modules through the switching device. The switching device can be a relay switch or a MOS transistor switch. Each charging sub-module is respectively provided with a battery pack interface and is connected to the pins of the main control chip; the internal power supply is respectively connected to the main control chip and the 485 communication module through wires to supply power to both; the main control chip samples the voltage signal from the DC input interface and controls the input of each charging sub-module by controlling the on / off of the switching device.

[0042] As an example, the DC input of the charging module comes from the DC power output of the AD-DC module; the internal power supply includes a 5V conversion power supply and a 5V isolation power supply; the 5V conversion power supply is connected through a wire to the DC input, and the 5V isolation power supply is a small isolation power supply that converts 5V to 5V and is used to supply power to the isolation terminal of the 485 communication.

[0043] In the charging module, the 485 communication module is respectively connected to the 485 communication interface and the main control chip. The main control chip can be an MCU main control chip; the charging sub-module can be a constant voltage and constant current charging chip with a BUCK architecture; the battery pack interface includes a positive terminal, a negative terminal, and a temperature wire terminal.

[0044] 4. Each AC-DC module and multiple charging modules form a charging group. The number of power sampling signal input interfaces, relay output interfaces, and 485 communication interfaces in the main control and display module is at least equal to the number of charging groups; the charging modules within the same charging group are respectively connected to the output terminals of the AC-DC module in parallel. The input terminal of the AC-DC module is connected to the AC power grid, converts alternating current into direct current, and supplies power to the charging modules within the group; the charging modules within the same group are respectively connected to the 485 communication interface of the main control and display module in parallel through signal lines.

[0045] To meet the needs of remote management and control, a wireless communication chip or a wired communication chip can be further set in the main control and display module, and the main control and display module is connected to a server located in the cloud through wireless or wired networking.

[0046] The second part: A specific application example

[0047] In this example, the overall framework of the charging system is as Figure 1 shown, and the main structural components include:

[0048] 1. Charging module: The input voltage of its DC input interface is direct current of 12 - 30V, which can convert the direct current provided by the AC-DC module into a constant voltage and constant current output to supply power to the battery pack. There are four charging sub-modules inside the charging module, which can simultaneously charge four battery packs independently. Its output voltage can be set to 2 - 22V, and the current can be set to 0 - 3A. Based on the main control chip, functions for detecting the voltage, current, and temperature of each battery pack are integrated, thus ensuring the safe charging of the battery pack. The charging module is configured with a 1-way 485 interface, enabling it to communicate with the main control display module, obtaining charging parameters while also uploading the charging information of each battery pack. Based on the MCU main control chip, digital control and 9-way AD sampling can be realized to control each charging sub-module in real time. At the same time, it can also monitor the input voltage of the DC input interface, and automatically implement input cut-off control to turn off the charging function of the charging sub-module when the input voltage is abnormal.

[0049] The charging module is mainly used to achieve independent charging of each battery pack, and its main structure is as Figure 2 shown. As an example, this charging module takes a high-performance 32-bit MCU main control chip based on ARM M0 as the core, responsible for setting the voltage and current of the four charging sub-modules, and at the same time responsible for collecting the information of the voltage, current, and temperature of each charging sub-module. To achieve input cut-off control, a P-type MOS can be selected for the conduction and cut-off of the input DC voltage. When the input voltage is higher or lower than the normal value by 20%, the input voltage will be cut off and the charging circuit will stop working. The four charging sub-modules adopt constant voltage and constant current charging chips with a BUCK architecture, with a maximum input voltage of 40V and a minimum output voltage of 2V. The MCU main control chip outputs a PWM wave through the IO pin, which is used as the comparison reference of the operational amplifier after RC filtering, and is compared with the feedback output voltage, and the output voltage value is adjusted to the set value through negative feedback. The setting method of the current is the same. The output current range of the charging sub-module is 0 - 3A, which is sufficient for common small battery packs on the market. The MCU main control chip communicates with the main control display module through the 485 communication module, and a dedicated 485 protocol chip and a digital isolation chip can be specifically used. At the same time, the internal power supply of the charging module adopts a 24V - 5V conversion power supply and a 5V - 5V isolation power supply to improve the reliability of 485 communication.

[0050] There are specific considerations for choosing the design of four charging sub-modules in this example:

[0051] 1. Since the set parameters and charging information of each charging module need to communicate with the main control display module, but the communication address is limited. For example, the maximum address of the Modbus communication protocol is generally only more than 240. Therefore, if a charging module can only charge one battery pack, the system can have at most more than 200. In the present utility model, 4-channel charging sub-modules are set for each charging module for output, so the charging system can charge nearly 1000 battery packs simultaneously at most, greatly expanding the number of charging packs.

[0052] 2. The performance of the currently commercially available MCU main control chip is high enough to easily process multi-channel charging data. Therefore, from the perspective of maximizing the performance of the MCU main control chip, saving communication modules, and reducing communication data, multi-channel charging output is also very necessary.

[0053] 3. For an MCU main control chip, the AD and PWM pins it has can support the output of 4-channel charging sub-modules and are sufficient. On this basis, if more outputs need to be supported, the performance of the chip may need to be further enhanced, which will increase the complexity of programming and the difficulty of debugging. In addition, if problems occur in the charging modules with more outputs, the number of affected charging battery packs will also increase. For a small charging system, the failure rate will be high, which may affect normal production charging.

[0054] Therefore, after full research and actual comparison, it is found that it is more appropriate for a single charging module to have 4-channel output. This is a choice that takes into account various requirements and also has a relatively high cost performance. This application provides a design sample of a charging module, as shown in Figure 2 shown.

[0055] 2. The AC-DC module uses 220V input and 24V voltage output. According to the different charging voltages and currents of the battery packs, a high-power power supply of 1000W can connect at most 50 charging modules for charging. Generally speaking, for a charging system with 200-channel output, 5 to 10 AC-DC modules can be configured according to the capacity of the battery packs to be charged.

[0056] The AC-DC module is a very mature product and can use common switching power supplies, and there are many choices in the current market.

[0057] 3. Master control and display module, which is exemplified by a 7-inch touch screen all-in-one computer and has AD sampling and relay output functions. It can receive the input and output voltage signals sampled by the AC-DC module. When it is found that the input voltage or output voltage of the AC-DC module is abnormal, it can control the front relay to disconnect the input to ensure the safety of the charging system. At the same time, the master control and display module is connected to each charging module through 485 communication, and the charging voltage, current and temperature protection values of each module can be set by means of centralized broadcast or individual setting. At the same time, the charging information of each charging module can be queried by polling to realize the monitoring and status display of each output battery pack in the system. The master control and display module is optionally configured with 4G communication, and the charging information of each charging module can be uploaded to the specified cloud server in real time through the wireless network, realizing functions such as remote monitoring of the charging status by users and automatic pop-up of alarm information APP, so as to ensure that users can master the status of the system in the first time and ensure safety.

[0058] The control and display module can directly select commercially available mature products. For example, a Tongtai touch display screen with 485 communication, or a programmable PLC touch screen with additional sampling and relay output functions. Some of these programmable products also have 4G communication and can directly upload data to the cloud server, which is convenient for users to view the device status at any time. In this example, a programmable touch screen with 4G communication is used, and a voltage transformer and a relay are additionally added to the AC-DC module to sample the input voltage of the system, and the relay is controlled according to the sampled voltage; when the voltage is abnormal, the input voltage can be cut off to protect the system safety.

[0059] Based on the above description, it can be seen that the multi-channel battery pack charging system of the present utility model, compared with similar products in the prior art, realizes safe and automatic charging for a large number of small-power charging packs, is simple and reliable, and has great price advantages, which is a suitable choice for battery pack manufacturers. The charging modules in the system can communicate with the master control and display module through 485 communication. The master control and display module can set parameters for each charging module. Each charging module can realize internal voltage, current and temperature monitoring and can transmit information to the master control and display module in real time. If assembled according to conventional electronic components, this product has great market competitiveness.

Claims

1. A charging system for a multi-channel battery pack based on the RS485 bus, characterized in that, The charging system includes a main control and display module, multiple AC-DC modules, and several charging modules; among them, the main control and display module includes a human-computer interaction interface, a processor, a memory, a 485 communication chip, a main control power module, as well as a power sampling signal input interface, a relay output interface, and a 485 communication interface; for the AC-DC module, its input end is connected to the AC power grid through a relay, and the relay is connected to the relay output interface of the main control and display module through a signal line; the output end of the AC-DC module is connected to the power sampling signal input interface of the main control module through a signal line, and is used to collect the output voltage of the AD-DC power supply; the charging module includes a main control chip, a 485 communication module, an internal power supply, a switching device, and multiple charging sub-modules; the charging module is provided with a DC input interface, and the DC input interface is connected to multiple charging sub-modules through a switching device; each charging sub-module is respectively provided with a battery pack interface and is respectively connected to the pins of the main control chip; the internal power supply is respectively connected to the main control chip and the 485 communication module through wires to supply power to both; the main control chip samples the voltage signal from the DC input interface and controls the input of each charging sub-module by controlling the on / off of the switching device; each AC-DC module and multiple charging modules form a charging group, and the number of the power sampling signal input interface, the relay output interface, and the 485 communication interface in the main control and display module is at least equal to the number of charging groups; the charging modules within the same charging group are respectively connected to the output end of the AC-DC module in a parallel manner, and the input end of the AC-DC module is connected to the AC power grid, converting AC into DC and supplying power to the charging modules within the group; the charging modules within the same group are respectively connected to the 485 communication interface of the main control and display module in a parallel manner through signal lines.

2. The charging system for multiple battery packs based on the RS485 bus according to claim 1, wherein The main control and display module includes a housing, and the processor, the memory, the 485 communication chip, and the main control power module are all arranged inside the housing; the human-computer interaction interface and each interface are all arranged on the housing, and the main control power module is connected to the 220V AC power grid through an interface end and a cable.

3. The charging system for multiple battery packs based on the RS485 bus according to claim 1, characterized in that, The main control and display module also includes redundant power sampling signal input interfaces, relay output interfaces, and 485 communication interfaces.

4. The charging system for a multi-channel battery pack based on the RS485 bus according to claim 1, characterized in that, The human-computer interaction interface is a touch screen that serves as both a display and an input interface, or a combination of an electronic display screen and a keyboard.

5. The charging system for multiple battery packs based on the RS485 bus according to claim 1, characterized in that The AC-DC module internally includes a rectification and filtering circuit, a buck circuit, and a voltage stabilization circuit; the input end of the AC-DC module accesses 220V AC, and its output end provides a DC voltage.

6. The charging system for a multi-channel battery pack based on the RS485 bus according to claim 1, wherein The DC input of the charging module comes from the DC power output of the AD-DC module; the internal power supply includes a 5V conversion power supply and a 5V isolation power supply; the 5V conversion power supply is connected through a DC input wire, and the 5V isolation power supply is a 5V-to-5V isolation small power supply used to supply power to the isolation end of the 485 communication.

7. The charging system for multiple battery packs based on the RS485 bus according to claim 1, characterized in that, In the charging module, the 485 communication module is respectively connected to the 485 communication interface and the main control chip.

8. The charging system for multiple battery packs based on the RS485 bus according to claim 1, characterized in that, In the charging module, the main control chip is an MCU main control chip, and the charging sub-module is a constant voltage and constant current charging chip with a BUCK architecture; the switching device is a relay switch or a MOS transistor switch.

9. The charging system for multiple battery packs based on the RS485 bus according to claim 1, wherein In the charging module, the battery pack interface includes a positive terminal, a negative terminal, and a temperature wire terminal.

10. The charging system for multiple battery packs based on the RS485 bus according to claim 1, characterized in that, In the main control and display module, there is a wireless communication chip or a wired communication chip, and the main control and display module is connected to a server provided in the cloud through wireless or wired networking.

Images