Temperature NTC protection circuit suitable for high-voltage lithium battery charging
By designing a temperature NTC protection circuit suitable for charging high-voltage lithium batteries, the hardware circuit design realizes automatic protection of high-temperature and low-temperature, the problem of insufficient temperature detection during charging of lithium batteries is solved, effectively preventing fires and battery cell damage. Reduced failure and scrap rate.
Patent Information
- Application Number
- CN202421114990.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-21
- Publication Date
- 2025-02-07
- Estimated Expiration
- 2034-05-21
AI Technical Summary
During the charging process of high-voltage lithium batteries, effective temperature detection and protection measures are lacking, which may cause high temperatures to cause fires, while low temperatures may damage the battery cell and affect service life.
A temperature NTC protection circuit suitable for charging high voltage lithium batteries is designed, and the hardware circuit design includes a first voltage comparator U1, a second voltage comparator U2, diode D1, diode D2, resistor R1 and resistor R2, through The NTC pin is connected to the voltage comparator to achieve automatic protection of high and low temperatures.
This protection circuit can automatically turn off the charging IC under high and low temperature conditions, effectively preventing fires and battery cell damage, reducing the failure rate and scrap rate of lithium batteries. At the same time, since there is no need for microcontroller control, it is low cost and easy to debug.
Smart Images
Figure CN222441348U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a charging protection circuit, in particular to a temperature NTC protection circuit suitable for charging a high-voltage lithium battery. Background Art
[0002] There are many lithium battery products on the market, especially some lithium batteries with more series connections and higher voltage. The surface temperature of lithium batteries is not detected during charging. The main reason is that there are few charging ICs that meet this demand on the market. The market mainly stays on low-voltage lithium battery charging ICs with relatively concentrated consumption. If the surface temperature of lithium batteries is not detected during charging, it is easy to catch fire when the temperature is too high, causing a fire; if the surface temperature of lithium batteries is not detected during charging, the battery cell is easily damaged when the temperature is too low, affecting the service life or even scrapping. Summary of the invention
[0003] The technical problem to be solved by the utility model is to provide a temperature NTC protection circuit suitable for high-voltage lithium battery charging, which uses hardware circuit design, has low cost, is easy to debug, and is suitable for high and low voltage lithium battery products.
[0004] In order to solve the above technical problems, the technical solution of the utility model is: a temperature NTC protection circuit suitable for high-voltage lithium battery charging, including a first voltage comparator U1, a second voltage comparator U2, a diode D1, a diode D2, a resistor R1 and a resistor R2; the lithium battery NTC pin is respectively connected to the inverting input end of the first voltage comparator U1 and the non-inverting input end of the second voltage comparator U2, the non-inverting input end of the first voltage comparator U1 is grounded through the resistor R1, the inverting input end of the second voltage comparator U2 is grounded through the resistor R2, the output end of the first voltage comparator U1 is connected to the anode of the diode D1, and the output end of the second voltage comparator U2 is connected to the anode of the diode D2. Principle of the utility model: When charging at high temperature, the resistance of the battery NTC foot to ground is 5.1K. When the temperature continues to rise, the resistance of the battery NTC foot to ground will decrease, so that the voltage of the third foot of the first voltage comparator U1 is higher than the voltage of the second foot, and the first foot of the first voltage comparator U1 outputs a high level, turning off the charging IC, and realizing the protection of the lithium battery during high-temperature charging; when charging at low temperature, the resistance of the battery NTC foot to ground is 27K. When the temperature continues to decrease, the resistance of the battery NTC foot to ground will increase, so that the voltage of the fifth foot of the second voltage comparator U2 is higher than the voltage of the sixth foot, and the first foot of the second voltage comparator U2 outputs a high level, turning off the charging IC, and realizing the protection of the lithium battery during low-temperature charging.
[0005] As an improvement, the cathode of the diode D1 and the cathode of the diode D2 are both connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected to the charging IC.
[0006] As an improvement, the resistance value of the resistor R1 is 5.1KΩ, and the resistance value of the resistor R2 is 27KΩ.
[0007] As an improvement, the power supply 22.5V is connected to the NTC pin of the lithium battery through the diode D3.
[0008] As an improvement, a resistor R3 is provided between the non-phase input terminal of the first voltage comparator U1 and the cathode of the diode D3, and a resistor R4 is provided between the output terminal of the first voltage comparator U1 and the cathode of the diode D3; a resistor R7 is provided between the inverting input terminal of the second voltage comparator U2 and the cathode of the diode D3, and a resistor R6 is provided between the output terminal of the second voltage comparator U2 and the cathode of the diode D3; the NTC foot of the lithium battery is grounded through the capacitor C1, and the cathode of the diode D3 is grounded through the capacitor C2.
[0009] Compared with the prior art, the utility model has the following beneficial effects:
[0010] The utility model does not need single chip microcomputer control, uses hardware circuit design, has low cost, is convenient for debugging, and is suitable for high and low voltage lithium battery products. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is the circuit schematic diagram of the utility model. DETAILED DESCRIPTION
[0012] The utility model will be further described below in conjunction with the accompanying drawings.
[0013] like Figure 1As shown, a temperature NTC protection circuit suitable for high-voltage lithium battery charging includes a first voltage comparator U1, a second voltage comparator U2, a diode D1, a diode D2, a resistor R1 and a resistor R2; the lithium battery NTC pin is respectively connected to the inverting input terminal of the first voltage comparator U1 and the non-inverting input terminal of the second voltage comparator U2, the non-inverting input terminal of the first voltage comparator U1 is grounded through the resistor R1, the inverting input terminal of the second voltage comparator U2 is grounded through the resistor R2, the output terminal of the first voltage comparator U1 is connected to the anode of the diode D1, the output terminal of the second voltage comparator U2 is connected to the anode of the diode D2, the cathode of the diode D1 and the cathode of the diode D2 are both connected to the base of the transistor Q1, and the The emitter of transistor Q1 is grounded, the collector of transistor Q1 is connected to the charging IC, the power supply 22.5V is connected to the NTC pin of the lithium battery through diode D3 and resistor R5 in sequence, a resistor R3 is provided between the positive input end of the first voltage comparator U1 and the cathode of diode D3, and a resistor R4 is provided between the output end of the first voltage comparator U1 and the cathode of diode D3; a resistor R7 is provided between the inverting input end of the second voltage comparator U2 and the cathode of diode D3, and a resistor R6 is provided between the output end of the second voltage comparator U2 and the cathode of diode D3; the NTC pin of the lithium battery is grounded through capacitor C1, the cathode of diode D3 is grounded through capacitor C2, and the base of transistor Q1 is grounded through capacitor C3. The resistance value of resistor R1 is 5.1KΩ, the resistance value of resistor R2 is 27KΩ, and the resistance values of resistors R3, R4, R5, R6 and R7 are 10KΩ.
[0014] Principle of the utility model: when charging at a high temperature of 45 degrees, according to the battery specification, at 45 degrees, the resistance of the battery NTC foot to ground is 5.1K. When the temperature continues to rise, the resistance of the battery NTC foot to ground will decrease, so that the voltage of the third foot of the first voltage comparator U1 is higher than the voltage of the second foot, and the first foot of the first voltage comparator U1 outputs a high level, turning off the charging IC, and realizing the protection of the lithium battery during high-temperature charging; when charging at a low temperature of 0 degrees, according to the battery specification, at 0 degrees, the resistance of the battery NTC foot to ground is 27K. When the temperature continues to decrease, the resistance of the battery NTC foot to ground will increase, so that the voltage of the fifth foot of the second voltage comparator U2 is higher than the voltage of the sixth foot, and the first foot of the second voltage comparator U2 outputs a high level, turning off the charging IC, and realizing the protection of the lithium battery during low-temperature charging.
Claims
1. A temperature NTC protection circuit suitable for high voltage lithium battery charging, characterized in that: It includes a first voltage comparator U1, a second voltage comparator U2, a diode D1, a diode D2, a resistor R1 and a resistor R2; the NTC pin of the lithium battery is respectively connected to the inverting input terminal of the first voltage comparator U1 and the non-inverting input terminal of the second voltage comparator U2, the non-inverting input terminal of the first voltage comparator U1 is grounded through the resistor R1, the inverting input terminal of the second voltage comparator U2 is grounded through the resistor R2, the output terminal of the first voltage comparator U1 is connected to the anode of the diode D1, and the output terminal of the second voltage comparator U2 is connected to the anode of the diode D2.
2. A temperature NTC protection circuit suitable for high voltage lithium battery charging according to claim 1, characterized in that: The cathode of the diode D1 and the cathode of the diode D2 are both connected to the base of the transistor Q1 , the emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected to the charging IC.
3. A temperature NTC protection circuit suitable for high voltage lithium battery charging according to claim 1, characterized in that: The resistance value of the resistor R1 is 5.1KΩ, and the resistance value of the resistor R2 is 27KΩ.
4. A temperature NTC protection circuit suitable for high voltage lithium battery charging according to claim 1, characterized in that: The power supply 22.5V is connected to the NTC pin of the lithium battery through the diode D3.
5. A temperature NTC protection circuit suitable for high voltage lithium battery charging according to claim 1, characterized in that: A resistor R3 is provided between the non-inverting input terminal of the first voltage comparator U1 and the cathode of the diode D3, and a resistor R4 is provided between the output terminal of the first voltage comparator U1 and the cathode of the diode D3; a resistor R7 is provided between the inverting input terminal of the second voltage comparator U2 and the cathode of the diode D3, and a resistor R6 is provided between the output terminal of the second voltage comparator U2 and the cathode of the diode D3; the NTC foot of the lithium battery is grounded through the capacitor C1, and the cathode of the diode D3 is grounded through the capacitor C2.