KR102583439B1 - Circuit for battery pack operation - Google Patents

Abstract

The circuit for driving the battery pack includes a battery cell, a switch connected in series to the battery cell to control the current flow between the battery cell and the remaining circuits of the battery pack, a DC-DC converter, and a preset circuit through a first line connected to the switch. It may include a control unit that outputs the first signal of the duty cycle at a predetermined output frequency. The switch may receive the first signal and the second signal output from the battery cell each time the switch is switched to the turn-on state and convert the signal. The control unit uses a DC-DC converter to receive the first and second signals output from the battery cell each time the switch is turned on, converts the signals, and converts the first and second conversion signals into Based on the comparison and satisfying specified conditions, it can be determined whether the battery pack is defective.

Description

Circuit for driving a battery pack {CIRCUIT FOR BATTERY PACK OPERATION}

This document is about the circuit for driving the battery pack. Specifically, a battery cell, a switch connected in series to the battery cell to control the current flow between the battery cell and the remaining circuits of the battery pack, a DC-DC converter, and a duty cycle preset through a first line connected to the switch. 1 This is about a circuit that includes a control unit that outputs a signal at a predetermined output frequency.

Recently, as the demand for portable electronic products such as laptops, video cameras, and portable phones has rapidly increased, and as the development of electric vehicles, energy storage batteries, robots, and satellites has begun, the need for high-performance batteries capable of repeated charging and discharging has increased. Research is actively underway.

Among high-performance batteries, research and development on secondary batteries has been actively conducted recently. Here, the secondary battery is a battery capable of charging and discharging, and includes both conventional Ni/Cd batteries, Ni/MH batteries, etc., and recent lithium ion batteries.

Currently commercialized batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium batteries. Among these, lithium batteries have almost no memory effect compared to nickel-based batteries, so they can be freely charged and discharged, and have a very high self-discharge rate. It is attracting attention due to its low and high energy density.

Among secondary batteries, lithium-ion batteries have the advantage of having a much higher energy density than conventional Ni/Cd batteries, Ni/MH batteries, etc. In addition, lithium-ion batteries are small and can be manufactured, so they are used as a power source for mobile devices. . In addition, lithium ion batteries are attracting attention as a next-generation energy storage medium as their range of use has expanded as a power source for electric vehicles.

Lithium-ion battery packs require the integration and management of numerous battery cells that contribute to the overall voltage output. As the number of battery cells included in a battery pack increases, if voltage problems such as voltage drops occur within the battery pack, it may be difficult to identify the specific cell causing the problem. Because a large number of battery cells are interconnected in a pack, the complexity and interdependence of the cell network can make it difficult to isolate the exact cell causing a voltage problem.

The circuit for driving the battery pack includes a battery cell, a switch connected in series to the battery cell to control the current flow between the battery cell and the remaining circuits of the battery pack, a DC-DC converter, and a preset circuit through a first line connected to the switch. It may include a control unit that outputs the first signal of the duty cycle at a predetermined output frequency. The switch may receive the first signal and the second signal output from the battery cell each time the switch is switched to the turn-on state and convert the signal. The control unit uses a DC-DC converter to receive the first and second signals output from the battery cell each time the switch is turned on, converts the signals, and converts the first and second conversion signals into Based on the comparison and satisfying specified conditions, it can be determined whether the battery pack is defective.

The circuit for driving the battery pack according to this document sets clear conditions for determining whether the battery pack is defective, and can relatively accurately determine whether the battery pack is defective even when it contains multiple battery cells.

The circuit for driving the battery pack according to this document controls the battery cells differently depending on the type of defect when the battery pack is determined to be defective, and can further provide a relatively accurate solution to whether the problem is with the switch.

The circuit for driving a battery pack according to this document can help monitor and balance the voltage level between battery cells.

Figure 1 is a block diagram showing the configuration of a circuit for driving a battery pack.
Figure 2 shows a circuit diagram of a battery protection circuit according to a comparative example.

A battery pack according to an embodiment of the present invention can store electrical energy and provide the stored electrical energy. Such a battery pack may include a plurality of battery cells capable of being charged and discharged.

Additionally, the battery pack may be comprised of a battery module comprised of a predetermined number of battery cells. That is, the battery pack may include at least one battery module and therefore may include a plurality of battery cells.

Additionally, when a plurality of battery cells constitute a battery module, each battery cell may be electrically connected to each other through various methods such as series and/or parallel. Here, the type of battery cell is not particularly limited. For example, types of battery cells may include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydride batteries, nickel zinc batteries, etc.

A battery pack consists of a series of high-capacity rechargeable battery cells. These cells may be lithium-ion, lithium-polymer, or any other suitable battery technology known in the art. They can be selected for their high energy density, long cycle life, and excellent power characteristics.

The circuitry may include a sophisticated battery management system (BMS) that monitors and controls the battery cells. A battery management system (BMS) can ensure optimal performance, safety, and longevity of the battery pack. The battery management system (BMS) manages cell balancing, temperature monitoring, voltage regulation, and current control.

To maintain uniform cell voltage levels and prevent cell degradation, the circuit may include cell balancing circuitry. Cell balancing circuitry can equalize charge/discharge levels between individual battery cells, increasing overall pack efficiency and extending battery life.

The circuit may include a comprehensive thermal management system that includes cooling elements such as heat sinks, heat pipes, or liquid cooling systems. The thermal management system dissipates heat generated during operation of the battery pack and ensures temperature uniformity across battery cells.

The circuit may include several safety features to prevent hazardous situations. The circuit may include overvoltage protection, undervoltage protection, overcurrent protection, short circuit protection and temperature monitoring modules. The control unit can perform safety functions and monitor the battery pack using overvoltage protection, undervoltage protection, overcurrent protection, short circuit protection, and temperature monitoring modules.

To enable bidirectional power flow and efficient energy conversion, the circuitry for driving the battery pack may include power components. The circuit for driving the battery pack may include a DC-DC converter, inverter, and/or charge controller. Power electronic components manage the flow of energy to and from the battery pack, tailoring it to the specific requirements of the application.

The circuit can exchange data with an external system using a communication interface such as a CAN bus or wireless communication module. The circuit can perform real-time monitoring and remote control using a communication interface.

Circuitry may include BMS, power electronics, communication interfaces and monitoring devices. The circuitry can monitor battery performance, configure operating parameters, and provide status notifications of the battery pack to the user terminal.

The circuit may include auxiliary components such as voltage sensors, current sensors, capacitors, fuses, and circuit breakers. The circuit can utilize auxiliary components to improve the pack's functionality, reliability and protection against electrical faults.

Figure 1 is a block diagram showing the configuration of a circuit for driving a battery pack.

According to FIG. 1, the circuit 100 for driving the battery pack may include a control unit 110, a converter 120, a switch 130, and a battery cell 140. The battery cell 140 refers to a unit for battery charging, and a plurality of battery cells can be gathered together to form a battery pack.

The switch 130 may be connected in series to the battery cell 140 to control current flow between the battery cell 140 and the remaining circuits of the battery pack.

Converter 120 may be used for power conversion and may include a DC-DC converter. The DC-DC converter can perform power conversion and voltage conversion within the battery pack. The converter 120 mainly converts the high voltage of the battery pack to a required voltage level or converts current to supply suitable power to other electronic devices or systems. The converter 120 may convert the input voltage and output voltage and minimize power loss.

DC-DC converters can be classified into switching mode and linear mode. Switching mode DC-DC converters can use a high-frequency switching waveform to divide the input voltage into small sections and perform voltage conversion through a transformer. DC-DC converters use high-frequency switching waveforms to enable efficient energy conversion and minimize power loss. Linear mode DC-DC converters can convert the voltage difference between input and output voltage by dissipating it through a resistor. Linear mode DC-DC converters are simple and inexpensive, but can be less efficient than switching mode ones.

The control unit 110 may include components capable of performing operations or data processing related to control and/or communication of each component within the circuit 100. Operations of the control unit 110 may be performed by loading instructions stored in memory (not shown).

According to one embodiment, the control unit 110 uses the DC-DC converter to receive the first signal and the second signal output from the battery cell each time the switch is switched to the turn-on state and convert the signal, By comparing the first conversion signal and the second conversion signal, it can be determined whether the battery pack is defective based on satisfying a specified condition.

According to one embodiment, the designated condition may include a condition in which the duty cycle and frequency of the first conversion signal and the second conversion signal are the same. The control unit 110 determines that the battery pack is not defective based on the fact that the duty cycle and frequency of the first conversion signal and the second conversion signal are the same, and the duty cycle of the first conversion signal and the second conversion signal It may be determined that the battery pack is defective based on at least one of the cycle or frequency not being the same.

According to one embodiment, the control unit 110 determines to perform additional diagnosis on the battery pack based on the battery pack being determined to be defective, and the battery cell 140 based on the battery pack being identified as being in an overvoltage state. ) is controlled to be below a specified level, the voltage of the battery cell 140 is raised to exceed the specified level based on the battery pack being identified as being in a low voltage state, and the temperature of the battery pack is exceeded the specified level. In the case of a defect, the temperature of the battery cell 140 is reduced by controlling the flowing current, and if a short circuit is confirmed within the battery pack, the electrical connection with the battery cell 140 affected by the short circuit is cut off to prevent additional loss. , Even though the battery pack is determined to be defective, if any of the problems of overvoltage, undervoltage, temperature, and short circuit do not occur, it is determined that the switch 130 is defective and a signal indicating that the switch 130 is defective is sent. It can be transmitted to the user terminal.

According to one embodiment, the specified condition may include a condition in which the voltage magnitudes of the first conversion signal and the second conversion signal are the same. The control unit 110 may determine that the battery pack is not defective based on the fact that the voltage levels of the first conversion signal and the second conversion signal are the same. The control unit 110 determines that the battery pack is defective based on the fact that the voltage levels of the first conversion signal and the secondary conversion signal are not the same, and determines that the battery pack is defective to protect the battery pack. The battery cell 140 can be controlled to change to a preset voltage level. Here, the preset voltage level may be determined differently based on the number of battery cells 140 included in the battery pack.

As the number of battery cells 140 increases, the effect on the voltage of the battery pack when the voltage of one battery cell decreases may be reduced. As the number of battery cells contained within a battery pack increases, the impact of a single cell's voltage drop on the overall pack voltage can be reduced by distributing the load across multiple cells.

The control unit 110 may control the preset voltage level to be lowered because the influence of one battery cell on the battery pack decreases as the number of battery cells 140 increases. Conversely, the control unit 110 can maintain the preset voltage level relatively large because the influence of one battery cell on the battery pack increases as the number of battery cells 140 becomes relatively small.

A battery pack can be constructed by combining multiple battery cells to supply greater power and energy. Battery cells can operate as individual electrochemical devices. The battery pack connects and manages battery cells to control the voltage, current, charging status, and safety of the entire system.

Figure 2 shows a circuit diagram of a battery protection circuit according to a comparative example.

Figure 2 is a circuit diagram of a battery protection circuit according to a comparative example. As shown in FIG. 2, the battery protection circuit 210 according to some embodiments of the present invention has first and second internal connection terminals (B+, B-) for connecting to the battery cell, and is connected to the charger when charging. It may be provided with first to third external connection terminals (P+, CF, P-) for connection to an electronic device (eg, a portable terminal, etc.) operated by battery power when discharging.

Here, among the first to third external connection terminals (P+, CF, P-), the first external connection terminal (P+) and the third external connection terminal (P -) are for power supply, and the remaining external connection terminal, The second external connection terminal (CF) can differentiate between batteries and charge them according to the battery type. Additionally, the second external connection terminal (CF) can be equipped with a thermistor, a component that detects battery temperature during charging, and can be used for other functions and as a terminal.

The battery protection circuit 210 includes a dual field effect transistor chip 230, a protection IC 220, a resistor (R1, R2, R3), a varistor (V1), and a capacitor (C1, C2). It may have a connection structure. The dual field effect transistor chip 230 is composed of a first field effect transistor (FET1) and a second field effect transistor (FET2) having a common drain structure. The protection integrated circuit unit 220 is connected to the first internal connection terminal (B +), which is the (+) terminal of the battery, through a resistor (R1), and the charging voltage or discharge voltage is applied through the first node (n1). and a terminal for detecting the battery voltage (VDD terminal), a reference terminal (VSS terminal) that serves as a standard for the operating voltage inside the protection IC 220, a detection terminal (V-terminal) for detecting charging/discharging and overcurrent conditions, A discharge blocking signal output terminal (DO terminal) for turning off the first field effect transistor (FET1) in an overdischarge state, and a charging blocking signal output terminal (C0 terminal) for turning off the second field effect transistor (FET2) in an overcharge state. has

When the protection IC 220 reaches an overdischarge state during discharge, the DO terminal becomes low to turn off the first field effect transistor (FET1), and when it reaches an overcharge state, the CO terminal becomes low to turn off the second field effect transistor (FET1). It is configured to turn off the field effect transistor (FET2), and when overcurrent flows, turn off the second field effect transistor (FET2) during charging and the first field effect transistor (FET1) during discharging.

The resistor (R1) and capacitor (C1) serve to stabilize fluctuations in the power supply to the protection IC (220). The resistor (R1) is connected between the first node (n1), which is the power supply (V1) supply node of the battery, and the VDD terminal of the protection IC (220), and the capacitor (C1) is connected between the VDD terminal and the VSS terminal of the protection IC. connected. Here, the first node (n1) is connected to the first internal connection terminal (B+) and the first external connection terminal (P+).

At this time, the inside of the protection IC 220 is provided with a reference voltage setting unit, a comparison unit for comparing the reference voltage and the charge/discharge voltage, an overcurrent detection unit, and a charge/discharge detection unit. Here, the standard for determining the charging and discharging state can be changed to the specifications requested by the user, and the voltage difference between each terminal of the protection IC 220 is recognized according to the set standard to determine the charging and discharging state.

And the resistor (R3) and varistor (V1) are elements for ESD (Electrostatic Discharge) and surge protection, and are connected in parallel to each other, and are connected to the second external connection terminal (CF) and the second node (n2). ) (or the third external connection terminal (P-)). The varistor (V1) is a device whose resistance is lowered when overvoltage occurs, so that circuit damage due to overvoltage can be minimized.

In some embodiments of the present invention, a battery protection circuit module is configured by packaging the battery protection circuit 210 of FIG. 4, including external connection terminals (P+, P-, CF) and internal connection terminals (B+, B-). Implementing the package. For example, passive elements such as resistors (R1, R2, R3), varistors (V1), and capacitors (C1, C2); Protection IC (220); and the dual field effect transistor chip 230; can be sealed and packaged with an encapsulant (M) to implement a battery protection circuit module package.

Claims (3)

In the circuit 100 for driving a battery pack,
battery cell 140;
A switch 130 connected in series to the battery cell to control current flow between the battery cell and the remaining circuits of the battery pack;
DC-DC converter (120);
It includes a control unit 110 that outputs a signal with a preset duty cycle at a predetermined output frequency through a first line connected to the switch,
The control unit 110 is
Using the DC-DC converter, when the switch is switched to the turn-on state, the first and second signals output from the battery cell are input at regular time intervals and converted into a first voltage conversion signal and a second voltage conversion signal, respectively. Convert to
Determining that the battery pack is not defective based on the fact that the voltage magnitudes of the first voltage conversion signal and the second voltage conversion signal are the same,
determining that the battery pack is defective based on the fact that the voltage magnitudes of the first voltage conversion signal and the second voltage conversion signal are not the same,
Based on the battery pack being determined to be defective, determining to perform additional diagnosis on the battery pack, and controlling the voltage applied to the battery cell 140 to below a specified level based on the battery pack being identified as being in an overvoltage state. And, based on the battery pack being identified as being in a low voltage state, the voltage of the battery cell 140 is raised to exceed a specified level, and if the temperature of the battery pack exceeds the specified level and is defective, the flowing current is controlled to control the battery cell ( 140), and if a short circuit is confirmed within the battery pack, the electrical connection with the battery cell 140 affected by the short circuit is cut off to prevent further loss, and even if the battery pack is determined to be defective, overvoltage, If any of the problems of low voltage, temperature, and short circuit do not occur, it is determined that the switch 130 is defective and a signal indicating that the switch 130 is defective is transmitted to the user terminal,
Based on the determination that the battery pack is defective, controlling the battery cell to change to a preset voltage level to protect the battery pack,
The preset voltage size is
It is determined differently based on the number of battery cells contained within the battery pack,
The control unit sets the preset voltage level relatively low based on the number of battery cells 140 exceeding (or exceeding) a specified number,
A circuit for driving a battery pack that sets the preset voltage size to be relatively large based on the fact that the number of battery cells 140 is less than a specified number.

According to clause 1,
The conditions specified above are
Includes the condition that the duty cycle and frequency of the first voltage conversion signal and the second voltage conversion signal are the same,
The control unit
Determining that the battery pack is not defective based on the fact that the duty cycle and frequency of the first voltage conversion signal and the second voltage conversion signal are the same,
A circuit for driving a battery pack that determines that the battery pack is defective based on the fact that at least one of the duty cycle or frequency of the first voltage conversion signal and the second voltage conversion signal is not the same.






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