KR102196351B1 - battery protection unit using embedded module and protection circuit mocdule - Google Patents

Abstract

The present invention relates to a battery energy storage module, which includes a protection circuit module (PCM) for managing a battery module composed of a plurality of battery cells, and an embedded module for managing individual temperatures of battery cells constituting the battery module. The battery energy storage module includes: a PCM which receives the voltage and current of the battery module and compares the voltage and current with preset Over Voltage Protection (OVP) and Under Voltage Protection (UVP) to stop or maintain charging and discharging; an embedded unit which detects the temperature of each of the battery cells and generates a signal to stop charging and discharging of the battery module when the detected temperature is higher than a preset temperature.

Description

Battery protection unit using embedded module and protection circuit mocdule}

The present invention relates to a battery energy storage module comprising a protection circuit mocdule (PCM) for managing a battery module consisting of a plurality of battery cells and an embedded module for managing individual temperatures of the battery cells constituting the battery module. About.

The Energy Storage System (ESS) is divided into a Power Conversation Syetem (PCS) and a Battery Energy Storage System (BESS). However, recently, fire accidents related to ESS using lithium batteries have occurred in Korea, and as a cause of such accidents, various measures to protect against thermal runaway of BESS have been studied. Registered Patent No. 10-1442188 (name of the invention: battery pack overheat warning device and method) (hereinafter referred to as “conventional technology”) was also developed to prevent thermal runaway of such a battery pack.

1 is a circuit diagram for explaining the overall configuration of the prior art.

The battery thermal warning device of the prior art is connected between the battery 100 and the load 160, and the sensing unit 110, the auxiliary power supply unit 120, the auxiliary power charging switch 125, the warning unit 130, and warning A switch 135, a control unit 140, a memory unit 150, and a charge/discharge control switch 165 are included.

The sensing unit 110 includes a first temperature sensor 112 that measures a surface temperature of a battery cell constituting the battery 100 and a second temperature sensor 114 that measures an outside temperature outside the battery pack. The first temperature sensor 112 periodically measures the surface temperature of the battery cell and outputs it to the controller 140. In addition, the second temperature sensor 114 periodically measures the outside air temperature outside the battery pack and outputs it to the controller 140. When the temperature difference between the first temperature sensor 112 and the second temperature sensor 114 is greater than a preset temperature difference, the controller 140 determines that the battery cell temperature is excessively increased. In such a configuration of the prior art, a technique for detecting an excessive increase in temperature due to a purely cause of the battery pack is implemented, excluding an increase in the temperature of the battery pack according to a change in the outside temperature.

However, BESS, which is generally used, uses hundreds of Wh and several Kwh-class battery energy storage modules (BESMs) connected in series and in parallel, and these BESMs consist of an integrated structure of battery cells. There is a problem in that it is difficult to apply the prior art, which is a method of measuring battery cell temperature of installed battery cells.

In this BESM, a protection circuit module (PCM) or a battery protection module (BPU) is used for thermal runaway and management of battery cells. Conventional PCM is designed to implement a function for battery protection due to overvoltage when charging individual batteries and undervoltage when discharging, and has some functions to detect and protect against overheating of the protection device and temperature rise inside the BESM.

However, since the temperature sensor installed in the PCM does not accurately detect the temperature of the battery cells, the temperature control of the battery cells could not be achieved accurately.

In addition, in the conventional protection method using PCM, the protection voltage range during overcharging and overdischarging differs from manufacturer to manufacturer. In some cases, the limit of battery protection occurred due to the protection range threshold by setting an excessive range compared to the battery performance. The necessity of configuring an embedded module to overcome the threshold limit of the (cell) voltage protection range was urgent.

The present invention was conceived in consideration of these points, and the problem of the present invention is to detect the exact temperature of individual battery cells, to control the temperature of each battery cell by an embedded module configuration, and to each of the battery cells. It is to implement optimal operation by setting the optimal current and power limit values.

In the battery protection device (BESM: Battery Energy Storage Module) using a PCM (Protection Circuit Module) and an embedded module for protecting a battery module formed by connecting a plurality of battery cells, the solution means for solving the problem is: the battery A PCM for stopping or maintaining charging and discharging of the battery module by comparing the voltages of the plurality of battery cells of the module with preset OVP (Over Voltage Protection) and UVP (Under Voltage Protection); Separately installed from the PCM, a second OVP lower than the OVP is set, a second UVP higher than the UVP is set, and voltages of each of the battery cells are input and compared with the second OVP and the second UVP Thus, when it exceeds the second OVP or decreases to less than the second UVP, the embedded unit generates a signal to stop charging and discharging of the battery module.
In addition, in the present invention, a temperature detection device for sensing the temperature of each of the battery cells is installed at a terminal of the battery cell or a connection part connecting the battery cells, and the temperature detection device is an NTC (Negative Temperature Coefficient) thermistor. Battery protection device using embedded module and PCM.

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The present invention having the above problems and solutions is a protection device for a lithium battery energy storage module using an embedded module and a PCM, which is a disadvantage of a protection circuit module (PCM) used as a protection device such as a battery module or pack. It overcomes the limitations of battery life management due to excessive depth of discharge (DOD) caused by voltage and current settings and the limitation of monitoring individual battery temperature inside a battery module configured in series. In addition, in order to protect the battery energy storage module in the present invention, a protection circuit in which an embedded module is combined in addition to the existing PCM is configured to protect the voltage and current at the module level and the internal temperature coefficient (NTC) thermistor. The safety of the BESM protection device has been improved by sensing the temperature of each of the batteries of, and by individually detecting the temperature for overcharging, over-discharging, or battery overheating due to abnormal conditions.

1 is a circuit diagram for explaining the overall configuration of the prior art.
2 is a block diagram for explaining the overall configuration of the present invention.
3 is a block diagram illustrating the PCM of the present invention.
4 is a port map of an embedded chip applied to the present invention.
5 is a voltage and current detection circuit connected to an embedded chip applied to the present invention.
6 is a temperature detection circuit connected to an embedded chip applied to the present invention.
7 is a relay driving circuit connected to an embedded chip applied to the present invention.
8A, 8B, and 8C are experimental graphs for detecting an appropriate temperature range of a battery cell in the present invention.
9 is a photograph of an experimental apparatus in which an actual circuit of the present invention is configured.
10 is a graph showing the module voltage characteristics of the BESM of the experimental system in the present invention.
11 is a photograph of the output display of the power analyzer in the experimental system configuration as shown in FIG. 9.

Hereinafter, embodiments of the present invention will be described in detail according to the accompanying drawings.

2 is a block diagram for explaining the overall configuration of the present invention.

The battery protection device (BESM: Battery Energy Storage Module) 1 of the present invention is for protecting the battery module 20, and the battery module 20 includes a plurality of unit cells (in the present invention, 8 unit cells are The connection is illustrated by way of example) and the battery module 20 is connected to the + and-terminals 10, and a charger (not shown) is connected to the terminal 10 to charge the battery module 20, When a load is connected to the terminal 10, charged electricity is supplied to the battery module 20.

BESM(1) receives the voltage of each of the battery unit cells, the voltage and current of the battery module 20, and stops charging and discharging by comparing it with preset OVP (Over Voltage Protection) and UVP (Under Voltage Protection). It is installed separately from the PCM (Protection Circuit Module) 40 and PCM 40 to be maintained, and receives the temperature of each of the battery unit cells inside the battery module 20. When the temperature is higher than a preset temperature, the battery module 20 is charged and The embedded part 30 that stops discharging and generates a signal for stopping or maintaining charging and discharging by comparing the voltage of the battery module 20 with the preset second OVP and the second UVP, and the battery module 20 It consists of a relay unit 50 for stopping or maintaining charging and discharging, and a relay driving unit 60 for driving the relay unit 50 by a signal from the embedded unit 30.

3 is a block diagram illustrating the PCM of the present invention.

3 is an exemplary diagram of a protection circuit applied to 1-Cell for battery protection through a PCM configuration, and PCM is an Over Voltage Protection (OVP) function, an Under Voltage Protection (UVP) function, and a low voltage prevention ( Under Voltage Protection, UVP) function and short circuit protection function.

The voltage between the + and-poles of each battery cell is detected by the resistor (R1) and input to the PCM chip (S-8xxx Series), and the current flowing between the positive poles during charging and discharging is detected by the resistor (R2). It is input to the chip. FET1 and FET2 are installed in the battery charging/discharging circuit. In the case of overcharging during battery charging, an abnormal voltage condition is detected by the PCM chip, and the battery is protected by turning off FET1. In addition, the PCM chip protects the battery by detecting a voltage abnormality due to overdischarging of the battery when discharging and turning off FET2. In addition, the PCM chip turns off FET1 and FET2 in order to stop charging and discharging when overcurrent flows into the circuit due to failure of the operating device connected to the BESM and PCM or an abnormality in the BESM. The PCM chip turns off FET1 and FET2 to cut off the converter to prevent fire and explosion when a large current flows due to an internal short circuit of the BESM or an external short circuit due to a malfunction of the operating device.

4 is a port map of an embedded chip applied to the present invention, FIG. 5 is a voltage and current detection circuit connected to an embedded chip applied to the present invention, and FIG. 6 is a temperature detection connected to an embedded chip applied to the present invention. Circuit, and FIG. 7 is a relay driving circuit connected to an embedded chip applied to the present invention.

The embedded processor of the embedded part 30 of the present invention uses the CB405RT core of Comfile Technology, and the specifications of the corresponding core are shown in Table 1. The applicable range for each item is 1CH for relay control, 2CH for cooling fan control, 8bit-8CH for individual temperature measurement of battery cells activated by ADC, 16bit-3CH for voltage, current and temperature/humidity measurement inside module, reset switch The hardware and software of the embedded processor for the battery protection device were configured by using 15CH such as 1CH for use, and 2CH in connection with RS232 for communication with HMI and external PC for checking management information.

Specification Application Program memory 200K bype - I/O Port 58 Data memory 106K RS232 CH. No. 3 HMI Interface ADC 16bit-8CH 2CH 8bit-8CH 8CH PWM 12CH - Clock 18.4320MHz -

임베디드 시스템은 넓은 범주에서 정의하면 특정한 목적을 가지고 만들어진 프로그래밍 가능한 모든 컴퓨터를 의미하는 것으로(https://dora-guide.com/%EC%9E%84%EB%B2%A0%EB%94%94%EB%93%9C-%EC%8B%9C%EC%8A%A4%ED%85%9C/),
본 발명의 임베디드부(30)의 OVP(Over Voltage Protection)는 PCM의 OVP 보다 낮게 설정되고, UVP(Under Voltage Protection)는 PCM의 UVP보다 높게 설정되도록 함으로써 보호대상의 배터리 모듈(20)을 최적으로 운용할 수 있도록 설정하는 것이 바람직하고, 일차적으로 배터리 모듈(20)의 보호는 임베디드부(30)에 효율적으로 이루어지도록 하고, 임베디드부(30)에서 보호되지 않는 이상 상태를 PCM에서 담당하도록 하도록 한다.

Embedded systems are defined in a broad category to mean any programmable computer built for a specific purpose (https://dora-guide.com/%EC%9E%84%EB%B2%A0%EB%94%94). %EB%93%9C-%EC%8B%9C%EC%8A%A4%ED%85%9C/),
The OVP (Over Voltage Protection) of the embedded part 30 of the present invention is set lower than the OVP of the PCM, and the Under Voltage Protection (UVP) is set higher than the UVP of the PCM to optimize the battery module 20 to be protected. It is desirable to set it so that it can be operated, and primarily, the protection of the battery module 20 is made to be efficiently performed in the embedded unit 30, and the PCM is in charge of an abnormal state that is not protected by the embedded unit 30. .

In addition, the embedded unit 30 of the present invention detects and inputs the temperatures of individual battery cells.

At this time, to detect the temperature of the battery cells, use an NTC (Negative Temperature Coefficient) thermistor whose resistance value decreases when the temperature increases, and the thermistor connects the terminals of the battery cells or adjacent battery cells after being wrapped by a heat shrink tube. It is desirable to directly sense the temperature of the battery cell by attaching it to the connecting part.

8A, 8B, and 8C are experimental graphs for detecting an appropriate temperature range of a battery cell in the present invention.

In order to understand the temperature characteristics of lithium iron phosphate (LiFePO4) battery cells with a capacity of 60Ah that constitute BESM, the environmental conditions for the experiment are 0.2, 0.5, and 1.0 C-rate at an ambient temperature of 25℃. Through a 1-cycle experiment for charging and discharging, the capacity and temperature rise characteristics as shown in FIG. 8 were derived. The protection voltage range was set to 3.60V for overvoltage and 2.80V for overdischarge to check the temperature characteristics by C-rate (charging rate) for the battery cell. Table 2 shows the maximum temperature rise value. Through this, it was confirmed that the negative electrode exhibits a higher temperature increase value than the positive electrode during charging and discharging, and therefore, it is preferable to install the thermistor on the negative electrode.

9 is a photograph of an experimental apparatus in which an actual circuit of the present invention is configured.

The 1kWh-class BESM of the experimental apparatus shown in FIG. 9 consists of eight lithium iron phosphate (LiFePO4) and 60Ah-class single cells in series, and the average lower limit voltage of the single cell is set to 3.0V to set the reference value for battery protection. Experimented. This means that the module lower limit voltage through the embedded is designed to be 24.0Vdc. Through charging at the reference voltage, it was confirmed that the output amount was greater than the target value of 1kWh at the module voltage of 27.32Vdc and the unit cell average upper limit voltage of 3.415Vdc, and the corresponding value was set as the average upper limit voltage. Table 2 shows the conditions for the lower limit voltage and upper limit voltage and the protection voltage range of the module for the 1kWh class BESM. In addition, it was confirmed that the cycle experiment through charging and discharging was conducted three times at 500W of input/output power to be continuously maintained for the 1kWh target value, and the experimental results are shown in Table 3, and FIG. It shows the module voltage characteristics, and it was confirmed that the protection operation was normally performed at the average lower limit voltage of 24.0Vdc and the average upper limit voltage of 27.32Vdc for the target output 1kWh class. FIG. 11 confirms that the output amount satisfying the target output amount of 1 kWh was output through the power analyzer in the experimental system configuration as shown in FIG. 9.

1: BESM
10: terminal
20: battery module
30: embedded part
40: PCM
50: relay unit

Claims (4)

In the Battery Energy Storage Module (BESM) using an embedded module and a Protection Circuit Module (PCM) to protect a battery module formed by connecting a plurality of battery cells:
A PCM for stopping or maintaining charging and discharging of the battery module by comparing the voltages of the plurality of battery cells of the battery module with preset OVP (Over Voltage Protection) and UVP (Under Voltage Protection);
Separately installed from the PCM, a second OVP lower than the OVP is set, a second UVP higher than the UVP is set, and voltages of each of the battery cells are input and compared with the second OVP and the second UVP Thus, the battery protection device using an embedded module and PCM, characterized in that it comprises an embedded unit for generating a signal to stop charging and discharging of the battery module when the second OVP exceeds or decreases to less than the second UVP. delete The method according to claim 1, wherein a temperature detection device for sensing the temperature of each of the battery cells is installed at a terminal of the battery cell or a connection part connecting the battery cells, and the temperature detection device is an NTC (Negative Temperature Coefficient) thermistor. Battery protection device using embedded module and PCM. delete

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