Lithium-ion battery pack series charge and discharge test control device, method and test cabinet

Abstract

The present invention relates to the technical field of battery pack charge and discharge test, and in particular to a lithium-ion battery pack series charge and discharge test control device, method and test cabinet, wherein the device includes a control circuit, the control circuit includes a number of unit circuits and controllers for connecting the battery pack in series to the main charge and discharge circuit; the unit circuit includes: a rectifier circuit module connected to the battery pack protection board through a power line, a voltage detection module connected to both ends of the battery pack power module, a resistor, a high-voltage relay and a high-voltage fuse connected in series to the total negative line outside the battery pack, and a power supply module for supplying power to the controller and the voltage detection module; the rectifier circuit module and the voltage detection module are both connected to the controller. The present invention can connect multiple lithium-ion battery packs in series for charge and discharge test in one channel, greatly improving the efficiency of low-voltage lithium-ion battery packs during production testing, while avoiding the high cost of purchasing multi-channel charge and discharge test equipment, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of battery pack charge and discharge testing, and in particular to a lithium-ion battery pack series charge and discharge test control device and method, and a lithium-ion battery pack charge and discharge test cabinet. Background Art

[0002] The lithium-ion power battery charge and discharge test cabinet is an electrical device with adjustable input, output voltage and current. It is often used to perform charge and discharge tests on lithium-ion power batteries of electric vehicles and electric bicycles to detect whether the functions and performance of lithium-ion power batteries are normal before leaving the factory. There are currently two types of lithium-ion power battery charge and discharge test cabinets, one is single-channel and the other is multi-channel. The single-channel test cabinet can only perform charge and discharge tests on one battery pack at a time. This solution is less efficient, but also less expensive; the multi-channel test cabinet can perform charge and discharge tests on multiple battery packs at a time. Each channel has a separate AC / DC module or DC / DC module, and the channels are connected in parallel. This solution can test multiple lithium-ion battery packs at a time, which is more efficient, but also more expensive. For lithium-ion power batteries of electric vehicles, their voltage is generally high, up to 700V or even higher, and the required voltage of the charge and discharge test cabinet is relatively high; while the voltage of lithium-ion power batteries of electric bicycles is generally within 70V, and the required voltage of the charge and discharge test cabinet is relatively low. For a charge and discharge test cabinet with a maximum voltage of 700V or even higher, if it is used to test power batteries below 70V, the performance of this channel cannot be fully utilized. Only one battery is tested at a time, which is inefficient. If multi-channel equipment is used, the equipment cost will be greatly increased.

[0003] Lithium-ion power batteries must be equipped with a battery management system. For lithium-ion power batteries in electric vehicles, they are equipped with lithium-ion battery protection boards. The lithium-ion battery protection board determines the battery status by collecting the voltage, battery temperature, and total battery current of each string of power batteries, and determines whether to cut off the main circuit of the power battery based on the real-time status of the battery. The protection board controls the connection and disconnection of the main circuit of the battery by controlling the high-power MOS tube. For a charging and discharging device with a single-channel maximum voltage of more than 700V, if one channel is used to test an electric bicycle battery pack at a time, it will cause a waste of resources and low efficiency; if multiple battery packs are connected in series in one channel for charging and discharging tests, when one of the battery packs is fully charged or discharged, the protection board of the battery pack will immediately cut off the main discharge circuit of the battery. At this time, the channel will be disconnected and the charging and discharging test can no longer continue. If it is in the charging state, the test cabinet will increase the charging voltage to the maximum voltage at this time, causing the MOS tube on the protection board to burn out due to excessive voltage; if the battery packs are connected in parallel in one channel, when the battery packs are connected in parallel, different battery packs will be charged and discharged with each other due to the voltage difference between the packs, and the protection board will easily cut off the main circuit due to excessive battery charging and discharging current. In addition, when charging and discharging, when one or more of the batteries are fully charged or discharged, the remaining current will be evenly distributed to other batteries. At this time, other batteries will be protected due to excessive charging and discharging current, resulting in the inability to proceed with the test. Summary of the invention

[0004] To this end, the present invention provides a lithium-ion battery pack series charge and discharge test control device and method and a lithium electronic battery pack charge and discharge test cabinet using the above control scheme, which solves the problem that a high-voltage charging cabinet can only charge one low-voltage lithium-ion battery pack at a time. By adding control equipment, multiple lithium-ion battery packs can be charged and discharged in series in one channel, greatly improving the efficiency of low-voltage lithium-ion battery packs during production testing, while avoiding the high cost of purchasing multi-channel charge and discharge test equipment.

[0005] According to the design scheme provided by the present invention, a lithium-ion battery pack series charge and discharge test control device includes a control circuit connected to a charge and discharge test cabinet, the control circuit includes a plurality of unit circuits for connecting the battery pack in series to a charge and discharge main circuit, and a controller connected to the plurality of unit circuits and the charge and discharge test cabinet; the unit circuit includes: a rectifier circuit module connected to a battery pack protection board via a power line, a voltage detection module connected to both ends of a battery pack power module, a resistor, a high-voltage relay and a high-voltage fuse connected in series in sequence to the total negative electrode circuit outside the battery pack, and a power supply module for supplying power to the controller and the voltage detection module; the rectifier circuit module and the voltage detection module are both connected to the controller.

[0006] As the lithium-ion battery pack series charge and discharge test control device of the present invention, further, the power line includes power line one and power line two respectively connected to the two ends of the battery pack protection board, and a resistor one is also connected in series between the power line one and the power line two, and the two ends of the resistor one are connected to the rectifier circuit module.

[0007] As the lithium-ion battery pack series charge and discharge test control device of the present invention, further, both ends of resistor one are connected to power line one and power line two respectively through conductive clips.

[0008] As the lithium-ion battery pack series charge and discharge test control device of the present invention, further, the rectifier circuit module includes a full-bridge rectifier circuit connected to the power line and a DC / DC circuit connected to the full-bridge rectifier circuit; the output end of the DC / DC circuit is connected to a 12V relay connected to the controller.

[0009] As the lithium-ion battery pack series charge and discharge test control device of the present invention, further, the power module also includes: a rectifier module for converting alternating current into direct current.

[0010] As the lithium-ion battery pack series charge and discharge test control device of the present invention, the control circuit further includes a high-voltage relay 1 that forms a parallel relationship with each unit circuit, and the two contacts of the high-voltage relay 1 are respectively connected to the total positive and total negative lines of the unit circuit.

[0011] As the lithium-ion battery pack series charge and discharge test control device of the present invention, further, a high-voltage relay 2 is also connected in parallel to the total negative electrode circuit outside the battery pack, and the two contact ends of the high-voltage relay 2 are connected to the resistance circuit on the total negative electrode circuit outside the battery pack.

[0012] As the lithium-ion battery pack series charge and discharge test control device of the present invention, further, each unit circuit is also provided with a buzzer, a working indicator light and a warning light which are respectively connected to the controller.

[0013] Furthermore, the present invention also provides a lithium-ion battery pack series charge and discharge test control method, which is implemented based on the above-mentioned device, and the implementation process includes the following contents:

[0014] During charging and discharging, a high-voltage relay is used to turn on the internal switch of the battery pack protection board, and current passes through the protection board for charging and discharging. When the battery pack is full or discharged, the protection board disconnects its internal switch, and the controller receives the disconnect signal of the internal switch of the protection board and uses a high-voltage relay to cut off the charging and discharging circuit of the battery pack, so that the battery pack is disconnected from the charging and discharging circuit. Other battery packs that are not full or discharged continue to charge and discharge. When all battery packs connected in series in the test cabinet channel are full or discharged, the controller cuts off the high-voltage main relay.

[0015] Furthermore, the present invention also provides a lithium electronic battery pack charge and discharge test cabinet, which is implemented based on the above-mentioned device and completes the series charge and discharge test of multiple lithium-ion battery packs in one channel of the charge and discharge test cabinet through the control device.

[0016] Beneficial effects of the present invention:

[0017] The present invention has a simple structure and a novel and reasonable design. By adding a control device, multiple lithium-ion battery packs can be connected in series in one channel for charge and discharge tests. When any one of the battery packs is fully charged or discharged, the controller can disconnect the charge and discharge circuit of this pack through the control circuit, and the remaining battery packs can continue to maintain the charging or discharging state until all the battery packs have completed charging and discharging. The controller can also automatically calculate the charge and discharge time of each battery pack, and calculate the capacity of each pack in combination with the collected current value. Each battery pack is connected to a voltage detection module. When the battery management system fails and causes the battery pack to exceed the upper and lower limit voltages allowed, the controller can immediately disconnect all high-voltage relays, stop the charge and discharge test, record the fault, and control the warning light and buzzer to alarm, thereby solving the problem that the high-voltage charging cabinet can only charge one low-voltage lithium-ion battery pack at a time, greatly improving the efficiency of the low-voltage lithium-ion battery pack during production testing, and avoiding the high cost of purchasing multi-channel charge and discharge test equipment. The present invention has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the control circuit of the lithium-ion battery pack series charge and discharge test control device in the embodiment. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and technical solutions, and the implementation methods of the present invention will be described in detail through preferred embodiments, but the implementation methods of the present invention are not limited thereto.

[0020] The embodiment of the present invention provides a lithium-ion battery pack series charge and discharge test control device, including a control circuit connected to a charge and discharge test cabinet, the control circuit includes a number of unit circuits for connecting the battery pack in series to the charge and discharge main circuit, and a controller connected to the number of unit circuits and the charge and discharge test cabinet; the unit circuit includes: a rectifier circuit module connected to the battery pack protection board through a power line, a voltage detection module connected to both ends of the battery pack power module, a resistor, a high-voltage relay and a high-voltage fuse connected in series to the total negative line outside the battery pack in sequence, and a power module for supplying power to the controller and the voltage detection module; the rectifier circuit module and the voltage detection module are both connected to the controller. By adding a control device, multiple lithium-ion battery packs can be charged and discharged in series in one channel, solving the problem that one channel of the charge and discharge test equipment can only charge and discharge one battery pack at a time.

[0021] As a lithium-ion battery pack series charge and discharge test control device in an embodiment of the present invention, further, the power line includes power line 1 and power line 2 respectively connected to the two ends of the battery pack protection board, and a resistor 1 is also connected in series between the power line 1 and the power line 2, and the two ends of the resistor 1 are connected to the rectifier circuit module. Further, the two ends of the resistor 1 are respectively connected to the power line 1 and the power line 2 through a conductive clip. Further, the rectifier circuit module includes a full-bridge rectifier circuit connected to the power line and a DC / DC circuit connected to the full-bridge rectifier circuit; the output end of the DC / DC circuit is connected to a 12V relay connected to the controller. Further, the power module also includes: a rectifier module for converting alternating current into direct current. Further, the control circuit also includes a high-voltage relay 1 that forms a parallel relationship with each unit circuit, and the two contacts of the high-voltage relay 1 are respectively connected to the total positive and total negative circuits of the unit circuit. Further, a high-voltage relay 2 is also connected in parallel to the total negative pole circuit outside the battery pack, and the two contact ends of the high-voltage relay 2 are connected to the resistor circuit on the total negative pole circuit outside the battery pack. Furthermore, each unit circuit is also provided with a buzzer, a working indicator light and a warning light which are respectively connected to the controller.

[0022] Furthermore, based on the above-mentioned device, an embodiment of the present invention also provides a lithium-ion battery pack series charge and discharge test control method, which includes the following contents:

[0023] During charging and discharging, a high-voltage relay is used to turn on the internal switch of the battery pack protection board, and current passes through the protection board for charging and discharging. When the battery pack is full or discharged, the protection board disconnects its internal switch, and the controller receives the disconnect signal of the internal switch of the protection board and uses a high-voltage relay to cut off the charging and discharging circuit of the battery pack, so that the battery pack is disconnected from the charging and discharging circuit. Other battery packs that are not full or discharged continue to charge and discharge. When all battery packs connected in series in the test cabinet channel are full or discharged, the controller cuts off the high-voltage main relay.

[0024] Furthermore, an embodiment of the present invention also provides a lithium electronic battery pack charge and discharge test cabinet, which is implemented based on the above-mentioned device, and the series charge and discharge test of multiple lithium-ion battery packs in one channel of the charge and discharge test cabinet is completed by the control device.

[0025] When multiple battery packs are connected in series for charge and discharge testing, the unit circuits in the control circuit are connected in series one by one. Figure 1As shown, in the unit circuit, the battery module and the protection board in the battery pack are in series relationship. The protection board controls the total negative pole of the battery pack. A power line is led to each end of the protection board, namely "power line 1, power line 2". Power line 1 and power line 2 are respectively connected to the two ends of the high-power resistor 1 with conductive clips. The two ends of the high-power resistor are connected to the input end of the DC / DC after passing through the full-bridge rectifier circuit. The output end of the DC / DC controls a 12V relay, and one output end of the relay is connected to the controller. The two signal input ends of the voltage monitoring module are respectively connected to the two ends of the battery module, and the output signal of the voltage monitoring module is connected to the control unit. AC / DC is a rectifier module for converting 220V AC to 12V DC. The 12V DC output provides system power to the control unit and the voltage monitoring module. A high-power resistor 2 is connected in series to the total negative pole outside the battery pack, and the two contact ends of the high-voltage relay 3 are connected in parallel with the high-power resistor 2. The high-voltage relay 2 and the high-voltage fuse are connected in series to the total negative pole of the battery pack. The two contact ends of the high-voltage relay 1 are respectively connected to the total positive and total negative ends of this control circuit, forming a parallel relationship with the entire control circuit. The high-voltage main relay and current sensor are connected in series in the main charging and discharging circuit. The high-voltage main relay, high-voltage relay 1, high-voltage relay 2, high-voltage relay 3, buzzer, working indicator light, and warning light are all controlled by the control unit. The control unit can send the collected data in real time through the CAN communication line.

[0026] When charging starts, high-voltage relay 1 is disconnected, high-voltage relay 2 is closed, and high-voltage relay 3 is closed. At this time, all parameters of the battery are normal, and the switch in the protection board is in the on state. At this time, the high-power resistor 1 connected in parallel with the protection board will be short-circuited, and the current will all pass through the protection board. The voltage across the high-power resistor 1 is 0V, and the DC / DC will not work at this time; when the battery is fully charged, the protection board will disconnect its internal switch because it detects that the battery is fully charged. At this time, the current will all flow through the high-power resistor 1, and a voltage will be generated across the high-power resistor 1. The voltage is: U=R×I, where U is the voltage across the high-power resistor 1, R is the resistance value of the high-power resistor 1, and I is the current flowing through the high-power resistor 1. At this time, the voltage U will be added to both ends of the DC / DC. The DC / DC starts to work and outputs 12V, the low-voltage relay will be driven, and the control unit will receive the protection board disconnection signal output by the relay. When the control unit receives the protection board disconnection signal, the control unit will first control the high-voltage relay 3 to disconnect and connect the high-power resistor 2 in series to the main circuit to prevent the high-voltage relay 1 from closing and causing the battery pack to form a discharge short circuit; it can be set that when the high-voltage relay 3 is disconnected for 50ms, the control unit immediately controls the high-voltage relay 1 to close, at which time the battery pack is short-circuited from the charging circuit, but the battery pack will still discharge through the high-power resistor 2; it can be set that when the high-voltage relay 1 is closed for 50ms, the control unit immediately controls the high-voltage relay 2 to disconnect, at which time the charging and discharging circuit of the battery pack is completely cut off. At this time, the battery is fully charged and disconnected from the charging circuit, while other uncharged battery packs continue to charge. When other battery packs are fully charged, the above process will be repeated until all battery packs are fully charged and the control unit cuts off the high-voltage main relay.

[0027] When the discharge starts, high-voltage relay 1 is disconnected, high-voltage relay 2 is closed, and high-voltage relay 3 is closed. At this time, all parameters of the battery are normal, and the switch in the protection board is in the on state. At this time, the high-power resistor 1 connected in parallel with the protection board will be short-circuited, and the current will all pass through the protection board. The voltage across the high-power resistor 1 is 0V, and the DC / DC will not work at this time; when the battery is fully discharged, the protection board will detect that the battery has reached the lower limit voltage and disconnect its internal switch. At this time, the current will all flow through the high-power resistor 1, and a voltage will be generated across the high-power resistor 1. The voltage size is: U=R×I, where U is the voltage across the high-power resistor 1 voltage, R is the resistance of high-power resistor 1, I is the current flowing through high-power resistor 1, at this time, voltage U will be added to both ends of DC / DC, DC / DC starts to work and outputs 12V, the low-voltage relay will be driven, and the control unit will receive the protection board disconnection signal output by the relay. When the control unit receives the protection board disconnection signal, the control unit will first close the high-voltage relay 1, and the battery pack will be short-circuited, but the battery pack will still discharge through the high-power resistor 1; it can be set that when the high-voltage relay 1 is closed for 50ms, the control unit immediately controls the high-voltage relay 2 to disconnect, and the discharge circuit of the battery pack is completely cut off. At this time, the battery has been discharged and disconnected from the discharge circuit, while other battery packs that have not been discharged continue to discharge. When other battery packs are discharged, the above process will be repeated until all battery packs are discharged and the control unit cuts off the high-voltage main relay.

[0028] Considering that the charging and discharging equipment has two states, charging and discharging, the current directions flowing through the high-power resistor 1 are opposite in the two states, so the voltage directions generated on the high-power resistor 1 are also opposite in the two states. Therefore, a full-bridge rectifier current needs to be added between the high-power resistor 1 and the DC / DC to ensure the normal operation of the DC / DC.

[0029] During the charging and discharging process, the control unit can read the charging and discharging current values ​​in real time through the current sensor, and determine the total charging and discharging time of each pack based on the protection board disconnection signal fed back by the control circuit of each battery pack, thereby calculating the capacity of each pack.

[0030] In the control circuit, a voltage monitoring module is connected at both ends of each battery pack. This monitoring module can monitor the voltage of the battery pack in real time and set the upper and lower voltage limits. When the battery pack voltage exceeds the set upper and lower voltage limits, the voltage monitoring module will output a voltage signal to the control unit. After receiving this signal, the control unit will immediately disconnect all high-voltage relays, stop the charge and discharge test, record the fault, and control the warning light and buzzer to alarm.

[0031] The term "and / or" in this article indicates that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" relationship.

[0032] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not necessarily indicate a quantity restriction. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not defined as physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0033] The exemplary embodiments of the present invention are described in detail above with reference to the preferred embodiments. However, it will be appreciated by those skilled in the art that, without departing from the concept of the present invention, various modifications and variations may be made to the above-mentioned specific embodiments, and various combinations of the various technical features and structures proposed in the present invention may be made without exceeding the scope of protection of the present invention, which is determined by the appended claims. The foregoing description of the specific exemplary embodiments of the present invention is not intended to limit the present invention to the precise form disclosed, and it is obvious that many changes and variations may be made according to the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present invention and various different choices and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A lithium-ion battery pack series charge and discharge test control device, comprising a control circuit connected to a charge and discharge test cabinet, characterized in that: The control circuit includes several unit circuits for connecting the battery pack in series in the main charging and discharging circuit, a high-voltage main relay, a current sensor, and a controller connected to the several unit circuits and the charging and discharging test cabinet, and the high-voltage main relay and the current sensor are connected in series in the main charging and discharging circuit; the unit circuit includes: a rectifier circuit module connected to the battery pack protection board through a power line, a voltage detection module connected to both ends of the battery pack power module, and a power module for supplying power to the controller and the voltage detection module; the rectifier circuit module and the voltage detection module are both connected to the controller, and the power line includes a power line 1 and a power line 2 respectively connected to both ends of the battery pack protection board, and a high-power resistor 1 is also connected in series between the power line 1 and the power line 2, and both ends of the high-power resistor 1 are connected to the rectifier circuit module, and both ends of the resistor 1 are connected to the rectifier circuit module. The rectifier circuit module comprises a full-bridge rectifier circuit connected to the power line and a DC / DC circuit connected to the full-bridge rectifier circuit; the output end of the DC / DC circuit is connected to a 12V relay connected to the controller; a high-power resistor 2 is connected in series to the total negative pole circuit outside the battery pack, and the high-power resistor 2 is connected in parallel with the two contact ends of the high-voltage relay 3; a high-voltage relay 2 and a high-voltage fuse are also connected in series to the total negative pole circuit outside the battery pack, and the two contact ends of the high-voltage relay 2 are connected to the high-power resistor 2 circuit on the total negative pole circuit outside the battery pack; the control circuit also comprises a high-voltage relay 1 which is connected in parallel with each unit circuit, and the two contacts of the high-voltage relay 1 are respectively connected to the total positive and total negative circuits of the unit circuit.

2. The lithium-ion battery pack series charge and discharge test control device according to claim 1, characterized in that: The power supply module also includes a rectifier module for converting alternating current into direct current.

3. The lithium-ion battery pack series charge and discharge test control device according to claim 1, characterized in that: Each unit circuit is also provided with a buzzer, a working indicator light and a warning light which are respectively connected with the controller.

4. A lithium-ion battery pack series charge and discharge test control method, characterized in that: Based on the device implementation of claim 1, the implementation process includes the following contents: During charging and discharging, high-voltage relay 1 is disconnected, high-voltage relay 2 is closed, high-voltage relay 3 is closed, the switch in the protection board is in the on state, the high-power resistor 1 connected in parallel with the protection board is short-circuited, and the current passes through the protection board for charging and discharging; When the battery pack is fully or discharged, the protection board disconnects its internal switch, and the controller receives the disconnect signal of the internal switch of the protection board. When the battery pack is fully charged, the high-voltage relay three is disconnected, the high-voltage relay one is closed, and the high-voltage relay two is disconnected to cut off the charge and discharge circuit of the battery pack. When the battery pack is fully discharged, the high-voltage relay one is closed and the high-voltage relay two is disconnected to cut off the charge and discharge circuit of the battery pack. When the battery pack is fully or discharged, the battery pack is disconnected from the charge and discharge circuit, and other battery packs that are not fully or discharged continue to charge and discharge. When all the battery packs connected in series in the test cabinet channel are fully or discharged, the controller cuts off the high-voltage main relay.

5. A lithium electronic battery pack charge and discharge test cabinet, characterized in that: A lithium-ion battery pack series charge and discharge test control device comprising any one of claims 1 to 3, through which a series charge and discharge test of multiple lithium-ion battery packs in one channel of a charge and discharge test cabinet is completed.

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