Battery protection chip with cell temperature detection

Abstract

The present invention provides a battery protection chip with battery cell temperature detection, which includes: a metal frame, which is partially exposed to the surface of the package of the battery protection chip; a battery protection chip, which includes a temperature sensing circuit, which conducts the heat of the battery cell into the interior of the battery protection chip through the metal frame, so that the temperature measured by the temperature sensing circuit can reflect the temperature of the temperature detection point of the battery cell. Compared with the prior art, the present invention exposes the metal frame portion of the battery protection chip to the surface of the package, and conducts the heat of the battery cell into the interior of the battery protection chip through the metal frame, so that the temperature sensing circuit in the battery protection chip and the battery cell achieve thermal balance. In this way, the present invention can not only reduce the chip pins required for battery cell temperature detection, which is conducive to chip miniaturization design, but also eliminates the need to set a thermistor outside the chip, thereby reducing the chip application cost.

Description

Technical field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to a battery protection chip with battery core temperature detection. [Background Technology]

[0002] To enhance safety, battery protection chips often incorporate a cell temperature detection function. Existing technologies typically require dedicated chip pins and an external temperature-sensitive resistor. The additional pins may require a larger package (to accommodate more pins), increasing chip cost; the additional temperature-sensitive resistor also increases chip application costs.

[0003] Therefore, it is necessary to propose a new technical solution to overcome the above problems. [Summary of the invention]

[0004] The purpose of the present invention is to provide a battery protection chip with cell temperature detection, which not only reduces the chip pins required for cell temperature detection, which is conducive to chip miniaturization design, but also eliminates the need to set up external temperature-sensitive resistors, thereby reducing chip application costs.

[0005] According to one aspect of the present invention, the present invention provides a battery protection chip with battery cell temperature detection, which includes: a metal frame, which is partially exposed on the surface of the package of the battery protection chip; a battery protection chip, which includes a temperature sensing circuit, which conducts the heat of the battery cell into the interior of the battery protection chip through the metal frame, so that the temperature measured by the temperature sensing circuit can reflect the temperature of the temperature detection point of the battery cell.

[0006] Compared to existing technologies, the present invention partially exposes the metal frame within the battery protection chip to the surface of the package. This metal frame conducts heat from the battery cells into the battery protection chip, achieving thermal equilibrium between the temperature sensing circuit within the battery protection chip and the battery cells. This not only reduces the number of chip pins required for cell temperature detection, facilitating chip miniaturization, but also eliminates the need for external temperature-sensitive resistors, reducing chip application costs.

Brief Description of the Drawings

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0008] Figure 1A three-dimensional diagram of a battery protection chip with cell temperature detection according to one embodiment of the present invention;

[0009] Figure 2 A three-dimensional diagram of a battery protection chip with cell temperature detection in another embodiment of the present invention;

[0010] Figure 3 A schematic diagram of the packaging and bonding of a battery protection chip with core temperature detection in one embodiment of the present invention;

[0011] Figure 4 This is a circuit diagram of a battery protection chip with cell temperature detection in the first embodiment of the present invention;

[0012] Figure 5 This is a circuit diagram of a battery protection chip with cell temperature detection in a second embodiment of the present invention;

[0013] Figure 6 FIG. 1 is a circuit diagram of a battery protection chip with cell temperature detection according to a third embodiment of the present invention. [Specific implementation method]

[0014] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] The term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to separate or selective embodiments that are mutually exclusive of other embodiments. Unless otherwise specified, the terms "connected," "connected," and "connected" herein, indicating electrical connection, refer to direct or indirect electrical connection.

[0016] The principle of the battery protection chip with core temperature detection of the present invention is:

[0017] Usually the chip needs to be packaged, and many packages use a metal frame (for example, sot23 package or DFN package or SOP package or SSOP package or TSSOP package, etc., all of these package forms use a metal frame). By designing the package, it is possible to design a way to expose part of the metal frame to the upper surface or lower surface of the package body of the battery protection chip (i.e., the belly of the chip). In a preferred embodiment, the metal frame is made of a material with good thermal conductivity (such as silver, copper, or aluminum, or silver-plated, copper-plated, aluminum-plated or alloy material). In actual applications, the battery protection chip of the present invention can be placed near a position where the battery cell needs to be temperature detected, especially the part of the metal frame exposed to the surface of the package body of the battery protection chip (which can be called the exposed part of the metal frame) is placed near a position where the battery cell needs to be temperature detected (i.e., the temperature detection point). Heat is introduced into the interior of the battery protection chip through this metal frame, so that thermal balance (i.e., the same temperature) is achieved. When in thermal equilibrium, the temperature sensing circuit inside the battery protection chip is the same temperature as the temperature detection point of the battery cell. That is, the temperature sensing circuit inside the battery protection chip achieves thermal equilibrium with the battery cell through the metal frame, and the temperature measured by the temperature sensing circuit reflects the temperature of the temperature detection point in the battery cell (or the temperature of the battery cell). Thus, the battery protection chip can determine the temperature of the temperature detection point of the battery cell (or the temperature of the battery cell) by detecting the temperature of the temperature sensing circuit.

[0018] Please refer to Figure 1 , which is a three-dimensional diagram of a battery protection chip with battery cell temperature detection in one embodiment of the present invention. Figure 1 The improvement using SOP8 as an example is described. A portion of the metal frame can be exposed on the top of the package (the shape of the exposed portion can be any shape: for example, circular, square, star-shaped, etc.). The larger the exposed metal area, the more conducive it is to heat conduction, which speeds up the heat conduction and achieves better results.

[0019] Please refer to Figure 2 , which is a three-dimensional diagram of a battery protection chip with battery cell temperature detection in another embodiment of the present invention. Figure 2 The improvement using SOP8 as an example is described. A portion of the metal frame can be exposed at the bottom of the package (the shape of the exposed portion can be any shape: for example, circular, square, star-shaped, etc.). The larger the exposed metal area, the more conducive it is to heat conduction, which accelerates the heat conduction speed and achieves better results.

[0020] Please refer to Figure 3As shown, it is a schematic diagram of the packaging and wiring of a battery protection chip with battery core temperature detection in one embodiment of the present invention. Among them, the metal frame 310 is a lead frame, which is used to carry the battery protection chip 320, and realize the electrical connection between the internal circuit of the battery protection chip 320 and the outside with the help of the packaging wire. A part of the metal frame 310 is exposed to the surface of the package of the battery protection chip. Among them, the black thick line is the packaging wire. In the present invention, metal wires with good thermal conductivity can be used, such as silver wire, gold wire, copper wire or alloy wire. It should be noted that in the present invention, Figure 3 In the embodiment shown, in order to enhance thermal conductivity, three metal wires (as shown by the three shortest black lines, in actual design, one or more metal wires may be used, and the more metal wires, the better the thermal conductivity) are used to connect the metal frame 310 and the thermal pad 322 provided on the battery protection chip 320. It should be noted that a die is an independent unit (or bare chip) cut from a wafer. In a preferred embodiment, a thermally conductive material (such as thermally conductive glue) can be applied to the back side of the battery protection chip 320 (or the surface of the battery protection chip 320 adjacent to the metal frame 310) to enhance the thermal conductivity of the metal frame 310 to the battery protection chip 320, so that the temperature sensing circuit in the battery protection chip 320 can better sense the temperature of the temperature detection point in the battery cell.

[0021] Please refer to Figure 4 , which is a circuit diagram of a battery protection chip with battery cell temperature detection in the first embodiment of the present invention. Figure 4 The circuit shown is set in the battery protection chip inside the battery protection chip, so it can also be said that Figure 4 The battery protection chip shown includes a temperature sensing circuit 410 , a temperature detection circuit 420 , a logic circuit 430 , a voltage detection circuit 440 , and a current detection circuit 450 .

[0022] The temperature sensing circuit 410 achieves thermal equilibrium with the battery cell through the metal frame 310, and the temperature measured by the temperature sensing circuit 410 is consistent with the temperature of the battery cell (or the temperature detection point of the battery cell). The input end of the temperature sensing circuit 420 is connected to the temperature sensing circuit 410, and its output end is connected to the input end of the logic circuit 430. The temperature sensing circuit 420 determines whether the temperature of the battery cell is abnormal based on the temperature measured by the temperature sensing circuit 410. When the temperature sensing circuit 420 determines that the temperature of the battery cell is abnormal, the logic circuit 430 outputs a charge prohibition control signal or a discharge prohibition control signal based on the determination result of the temperature sensing circuit 420.

[0023] exist Figure 4In the illustrated embodiment, the temperature sensing circuit 410 includes a first current source I1 and a PNP transistor Q1. The input of the first current source I1 is connected to the power supply VDD, and the output of the first current source I1 is connected to the emitter of the PNP transistor Q1. The base and collector of the PNP transistor Q1 are both grounded. Because the base-emitter voltage of the PNP transistor Q1 has a negative temperature coefficient (i.e., it decreases with increasing temperature), the connection node between the output of the first current source I1 and the emitter of the PNP transistor Q1 provides a temperature-sensitive voltage EQ1 reflecting the temperature of the battery cell. This temperature-sensitive voltage EQ1 has a negative temperature coefficient.

[0024] exist Figure 4In the specific embodiment shown, the temperature detection circuit 420 includes a first comparator Comp1 and a second comparator Comp2, wherein the inverting input terminal of the first comparator Comp1 is connected to the temperature-sensitive voltage EQ1, the non-inverting input terminal thereof is connected to the first reference voltage VT1, and the output terminal thereof is connected to the input terminal of the logic circuit 430; the non-inverting input terminal of the second comparator Comp2 is connected to the temperature-sensitive voltage EQ1, the inverting input terminal thereof is connected to the second reference voltage VT2, and the output terminal thereof is connected to the input terminal of the logic circuit 430, wherein the first reference voltage VT1 is less than the second reference voltage VT2. When the temperature of the battery cell rises, the temperature-sensitive voltage EQ1 will decrease. When it decreases to below the first reference voltage VT1, the output of the comparator Comp1 becomes a high level, indicating that the battery cell temperature is too high (that is, the battery cell temperature is abnormal). The logic circuit 430 can be used to control the charging control terminal CO to output a low level (which can be called a charging prohibition control signal) to control the battery cell to prohibit charging, thereby realizing the high-temperature charging protection function; when the battery cell temperature decreases, the temperature-sensitive voltage EQ1 will increase. When it increases to above the second reference voltage VT2, the output of the comparator Comp2 becomes a high level, indicating that the battery cell temperature is too low (that is, the battery cell temperature is abnormal). The logic circuit 430 can be used to control the charging control terminal CO to output a low level (which can be called a charging prohibition control signal) to control the battery cell to prohibit charging, thereby realizing the low-temperature charging protection function. Based on similar principles, high-temperature discharge protection and low-temperature discharge protection can be implemented by modifying the logic circuit 430: when the cell temperature increases, the temperature-sensitive voltage EQ1 decreases. When it decreases to below the first reference voltage VT1, the comparator Comp1 output becomes high, indicating that the cell temperature is too high (i.e., the cell temperature is abnormal). The logic circuit 430 can be used to control its discharge control terminal DO to output a low level (which can be called a discharge prohibition control signal), controlling the cell to prohibit discharge, thus implementing the high-temperature discharge protection function; when the cell temperature decreases, the temperature-sensitive voltage EQ1 increases. When it increases to the high-voltage second reference voltage VT2, the comparator Comp2 output becomes high, indicating that the cell temperature is too low (i.e., the cell temperature is abnormal). The logic circuit 430 can be used to control its discharge control terminal DO to output a low level (which can be called a discharge prohibition control signal), controlling the cell to prohibit discharge, thus implementing the low-temperature discharge protection function. It can be understood that by adding two comparators and corresponding reference voltages, the high-temperature discharge protection function, the low-temperature discharge protection function, the high-temperature charging protection function, and the low-temperature charging protection function can be implemented simultaneously.

[0025] That is to say, in Figure 4In the illustrated embodiment, the temperature-sensitive voltage EQ1 is a negative temperature coefficient voltage, and the first reference voltage VT1 is less than the second reference voltage VT2. When the temperature-sensitive voltage EQ1 is lower than the first reference voltage VT1, the temperature detection circuit 420 determines that the battery cell temperature is too high. The logic circuit 430 outputs a charge prohibition control signal through its charge control terminal CO based on the determination result of the temperature detection circuit 420 to control the battery cell to prohibit charging; when the temperature-sensitive voltage EQ1 is higher than the second reference voltage VT2, the temperature detection circuit 420 determines that the battery cell temperature is too low. The logic circuit 430 outputs a charge prohibition control signal through its charge control terminal CO based on the determination result of the temperature detection circuit 420 to control the battery cell to prohibit charging. and / or the third reference voltage VT3 is less than the fourth reference voltage VT4. When the temperature-sensitive voltage EQ1 is lower than the third reference voltage VT3, the temperature detection circuit 420 determines that the temperature of the battery cell is too high, and the logic circuit 430 outputs a prohibit discharge control signal through its discharge control terminal DO based on the determination result of the temperature detection circuit 420 to control the battery cell to prohibit discharge; when the temperature-sensitive voltage EQ1 is higher than the fourth reference voltage VT4, the temperature detection circuit 420 determines that the temperature of the battery cell is too low. The logic circuit 430 outputs a prohibit discharge control signal through its discharge control terminal DO based on the determination result of the temperature detection circuit 420 to control the battery cell to prohibit discharge.

[0026] One input terminal of the voltage detection circuit 440 is connected to the power supply terminal VDD, another input terminal thereof is connected to the ground terminal G, and an output terminal thereof is connected to the logic circuit 430. The voltage detection circuit 440 is used to detect whether the cell voltage is abnormal during charging and discharging. One input terminal of the current detection circuit 450 is connected to the detection terminal VM, another input terminal thereof is connected to the ground terminal G, and an output terminal thereof is connected to the logic circuit 430. The current detection circuit 450 is used to detect whether the cell current is abnormal during charging and discharging. When the voltage detection circuit 440 detects that the cell voltage is abnormal or the current detection circuit 450 detects that the cell current is abnormal, the logic circuit 430 outputs a charge prohibition control signal through its charge control terminal CO or outputs a discharge prohibition control signal through its discharge control terminal DO based on the detection results of the voltage detection circuit 440 and the current detection circuit 450, so as to implement charging overvoltage protection, discharging overvoltage protection, charging overcurrent protection, discharging overcurrent protection, etc. The specific circuit structure and working principle of the voltage detection circuit 440 and the current detection circuit 450 can be found in the prior art and will not be repeated here.

[0027] In a preferred embodiment, Figure 3 The thermal pad 322 connected to three metal wires is connected to the Figure 4In a preferred embodiment, during layout design, the PNP transistor Q1 is placed below or near the thermal pad 322 connected to the three metal wires to enhance thermal conductivity.

[0028] Please refer to Figure 5 , which is a circuit diagram of a battery protection chip with cell temperature detection in a second embodiment of the present invention. Figure 5 The circuit shown is set in the battery protection chip inside the battery protection chip, so it can also be said that Figure 5 The battery protection chip shown includes a temperature sensing circuit 510 , a temperature detection circuit 520 , a logic circuit 530 , a voltage detection circuit 540 , and a current detection circuit 550 .

[0029] The temperature sensing circuit 510 achieves thermal equilibrium with the battery cell through the metal frame 310, and the temperature measured by the temperature sensing circuit 510 is consistent with the temperature of the battery cell (or the temperature detection point of the battery cell). The input end of the temperature detection circuit 520 is connected to the temperature sensing circuit 510, and its output end is connected to the input end of the logic circuit 530. The temperature detection circuit 520 determines whether the temperature of the battery cell is abnormal based on the temperature measured by the temperature sensing circuit 510. When the temperature detection circuit 520 determines that the temperature of the battery cell is abnormal, the logic circuit 530 outputs a charge prohibition control signal or a discharge prohibition control signal based on the determination result of the temperature detection circuit 520.

[0030] exist Figure 5 In the specific embodiment shown, the temperature sensing circuit 510 includes a first current source I1 , a second current source I2 , a first NPN transistor Q1 , a second NPN transistor Q2 , and a resistor R1 .

[0031] Among them, the input end of the first current source I1 is connected to the power supply end VDD, and the output end thereof is connected to the collector of the first NPN-type transistor Q1. The emitter of the first NPN-type transistor Q1 is grounded via the resistor R1, and the base of the first NPN-type transistor Q1 is connected to the base of the second NPN-type transistor Q2. The input end of the second current source I2 is connected to the power supply end VDD, and the output end thereof is connected to the collector of the second NPN-type transistor Q2. The base of the second NPN-type transistor Q2 is connected to its collector, and the emitter of the second NPN-type transistor Q2 is grounded. The connection node between the emitter of the first NPN-type transistor Q1 and the resistor R1 provides the temperature-sensitive voltage EQ1. By designing the emitter area of the first NPN transistor Q1 to be larger than the emitter area of the second NPN transistor Q2, it is possible to achieve a base-emitter voltage of the second NPN transistor Q2 that is greater than the base-emitter voltage of the first NPN transistor Q1. The difference between the base-emitter voltage and the base-emitter voltage is ΔVbe, where ΔVbe is a positive temperature coefficient voltage (i.e., it increases with increasing temperature). Therefore, the temperature-sensitive voltage EQ1 provided by the connection node between the emitter of the first NPN transistor Q1 and the resistor R1 is a positive temperature coefficient voltage.

[0032] exist Figure 5In the specific embodiment shown, the temperature detection circuit 520 includes a first comparator Comp1 and a second comparator Comp2, wherein the non-inverting input terminal of the first comparator Comp1 is connected to the temperature-sensitive voltage EQ1, the inverting input terminal thereof is connected to the first reference voltage VT1, and the output terminal thereof is connected to the input terminal of the logic circuit 530; the inverting input terminal of the second comparator Comp2 is connected to the temperature-sensitive voltage EQ1, the non-inverting input terminal thereof is connected to the second reference voltage VT2, and the output terminal thereof is connected to the input terminal of the logic circuit 530, wherein the first reference voltage VT1 is greater than the second reference voltage VT2. When the cell temperature rises, the temperature-sensitive voltage EQ1 will increase. When it increases to higher than the first reference voltage VT1, the comparator Comp1 output becomes a high level, indicating that the cell temperature is too high (i.e., the cell temperature is abnormal). The logic circuit 530 can be used to control the charging control terminal CO to output a low level (which can be called a charging prohibition control signal) to prohibit the cell from charging, thereby realizing the high-temperature charging protection function; when the cell temperature decreases, the temperature-sensitive voltage EQ1 will decrease. When it decreases to lower than the second reference voltage VT2, the comparator Comp2 output becomes a high level, indicating that the cell temperature is too low (i.e., the cell temperature is abnormal). The logic circuit 530 can be used to control the charging control terminal CO to output a low level (which can be called a charging prohibition control signal) to prohibit the cell from charging, thereby realizing the low-temperature charging protection function. Based on similar principles, high-temperature discharge protection and low-temperature discharge protection can be implemented by modifying the logic circuit 530: when the cell temperature rises, the temperature-sensitive voltage EQ1 increases. When it increases to a value higher than the first reference voltage VT1, the comparator Comp1 output becomes high, indicating that the cell temperature is too high (i.e., the cell temperature is abnormal). The logic circuit 530 can be used to control its discharge control terminal DO to output a low level (which can be called a discharge prohibition control signal), controlling the cell to prohibit discharge, thus implementing the high-temperature discharge protection function. When the cell temperature decreases, the temperature-sensitive voltage EQ1 decreases. When it decreases to a value lower than the second reference voltage VT2, the comparator Comp2 output becomes high, indicating that the cell temperature is too low (i.e., the cell temperature is abnormal). The logic circuit 530 can be used to control its discharge control terminal DO to output a low level (which can be called a discharge prohibition control signal), controlling the cell to prohibit discharge, thus implementing the low-temperature discharge protection function. It can be understood that by adding two comparators and corresponding reference voltages, the high-temperature discharge protection function, the low-temperature discharge protection function, the high-temperature charging protection function, and the low-temperature charging protection function can be implemented simultaneously.

[0033] That is to say, in Figure 5In the illustrated embodiment, the temperature-sensitive voltage EQ1 is a positive temperature coefficient voltage, and the first reference voltage VT1 is greater than the second reference voltage VT2. When the temperature-sensitive voltage EQ1 is higher than the first reference voltage VT1, the temperature detection circuit 520 determines that the battery cell temperature is too high. The logic circuit 530 outputs a charge prohibition control signal through its charge control terminal CO based on the determination result of the temperature detection circuit 520 to control the battery cell to prohibit charging; when the temperature-sensitive voltage EQ1 is lower than the second reference voltage VT2, the temperature detection circuit 520 determines that the battery cell temperature is too low. The logic circuit 530 outputs a charge prohibition control signal through its charge control terminal CO based on the determination result of the temperature detection circuit 520 to control the battery cell to prohibit charging. and / or the third reference voltage VT3 is greater than the fourth reference voltage VT4. When the temperature-sensitive voltage EQ1 is higher than the third reference voltage VT3, the temperature detection circuit 520 determines that the temperature of the battery cell is too high, and the logic circuit 530 outputs a prohibit discharge control signal through its discharge control terminal DO based on the determination result of the temperature detection circuit 520 to control the battery cell to prohibit discharge; when the temperature-sensitive voltage EQ1 is lower than the fourth reference voltage VT4, the temperature detection circuit 520 determines that the temperature of the battery cell is too low. The logic circuit 530 outputs a prohibit discharge control signal through its discharge control terminal DO based on the determination result of the temperature detection circuit 520 to control the battery cell to prohibit discharge.

[0034] The voltage detection circuit 540 and Figure 4 The voltage detection circuit 440 is consistent with the current detection circuit 550. Figure 4 The current detection circuit 450 is the same as that shown in FIG. Figure 4 The description of the voltage detection circuit 440 and the current detection circuit 450 is omitted here.

[0035] In a preferred embodiment, Figure 3 The thermal pad 322 connected to three metal wires is connected to the Figure 5 The bases of the first NPN transistor Q1 and the second NPN transistor Q2 are placed below or near the thermal pad 322 connected to the three metal wires during layout design to enhance thermal conductivity.

[0036] Please refer to Figure 6 , which is a circuit diagram of a battery protection chip with cell temperature detection in the third embodiment of the present invention. Figure 6 The circuit shown is set in the battery protection chip inside the battery protection chip, so it can also be said that Figure 6The battery protection chip shown includes a temperature sensing circuit 610 , a temperature detection circuit 620 , a logic circuit 630 , a voltage detection circuit 640 , and a current detection circuit 650 .

[0037] The temperature sensing circuit 610 achieves thermal equilibrium with the battery cell through the metal frame 310, and the temperature measured by the temperature sensing circuit 610 is consistent with the temperature of the battery cell (or the temperature detection point of the battery cell). The input end of the temperature detection circuit 620 is connected to the temperature sensing circuit 610, and its output end is connected to the input end of the logic circuit 630. The temperature detection circuit 620 determines whether the temperature of the battery cell is abnormal based on the temperature measured by the temperature sensing circuit 610. When the temperature detection circuit 620 determines that the temperature of the battery cell is abnormal, the logic circuit 630 outputs a charge prohibition control signal or a discharge prohibition control signal based on the determination result of the temperature detection circuit 620.

[0038] exist Figure 6 In the illustrated embodiment, the temperature sensing circuit 610 includes a first current source I1 and a resistor R1. The input of the first current source I1 is connected to the power supply terminal VDD, and the output of the first current source I1 is grounded via the resistor R1. The connection node between the output of the first current source I1 and the resistor R1 provides the temperature-sensitive voltage VR1. Because the resistor R1 is a positive temperature coefficient resistor and I1 is a zero temperature coefficient current source, the temperature-sensitive voltage VR1 provided by the connection node between the output of the first current source I1 and the resistor R1 is a positive temperature coefficient voltage.

[0039] exist Figure 6In the specific embodiment shown, the temperature detection circuit 620 includes a first comparator Comp1 and a second comparator Comp2, wherein the non-inverting input terminal of the first comparator Comp1 is connected to the temperature-sensitive voltage VR1, the inverting input terminal thereof is connected to the first reference voltage VT1, and the output terminal thereof is connected to the input terminal of the logic circuit 630; the inverting input terminal of the second comparator Comp2 is connected to the temperature-sensitive voltage VR1, the non-inverting input terminal thereof is connected to the second reference voltage VT2, and the output terminal thereof is connected to the input terminal of the logic circuit 630, wherein the first reference voltage VT1 is greater than the second reference voltage VT2. When the temperature of the battery cell rises, the temperature-sensitive voltage VR1 will increase. When it increases to higher than the first reference voltage VT1, the output of the comparator Comp1 becomes a high level, indicating that the battery cell temperature is too high (that is, the battery cell temperature is abnormal). The logic circuit 630 can be used to control the charging control terminal CO to output a low level (which can be called a charging prohibition control signal) to control the battery cell to prohibit charging, thereby realizing the high-temperature charging protection function; when the battery cell temperature drops, the temperature-sensitive voltage VR1 will decrease. When it decreases to lower than the second reference voltage VT2, the output of the comparator Comp2 becomes a high level, indicating that the battery cell temperature is too low (that is, the battery cell temperature is abnormal). The logic circuit 630 can be used to control the charging control terminal CO to output a low level (which can be called a charging prohibition control signal) to control the battery cell to prohibit charging, thereby realizing the low-temperature charging protection function. Based on similar principles, high-temperature discharge protection and low-temperature discharge protection can be implemented by modifying the logic circuit 630: when the cell temperature rises, the temperature-sensitive voltage VR1 increases. When it increases to a value higher than the first reference voltage VT1, the comparator Comp1 output becomes high, indicating that the cell temperature is too high (i.e., the cell temperature is abnormal). The logic circuit 630 can be used to control its discharge control terminal DO to output a low level (which can be called a discharge prohibition control signal), controlling the cell to prohibit discharge, thus implementing the high-temperature discharge protection function. When the cell temperature decreases, the temperature-sensitive voltage VR1 decreases. When it decreases to a value lower than the second reference voltage VT2, the comparator Comp2 output becomes high, indicating that the cell temperature is too low (i.e., the cell temperature is abnormal). The logic circuit 630 can be used to control its discharge control terminal DO to output a low level (which can be called a discharge prohibition control signal), controlling the cell to prohibit discharge, thus implementing the low-temperature discharge protection function. It can be understood that by adding two comparators and corresponding reference voltages, the high-temperature discharge protection function, the low-temperature discharge protection function, the high-temperature charging protection function, and the low-temperature charging protection function can be implemented simultaneously.

[0040] That is to say, in Figure 6In the illustrated embodiment, the temperature-sensitive voltage VR1 is a positive temperature coefficient voltage, and the first reference voltage VT1 is greater than the second reference voltage VT2. When the temperature-sensitive voltage VR1 is higher than the first reference voltage VT1, the temperature detection circuit 620 determines that the battery cell temperature is too high, and the logic circuit 630 outputs a charge prohibition control signal through its charge control terminal CO based on the determination result of the temperature detection circuit 620 to control the battery cell to prohibit charging; when the temperature-sensitive voltage VR1 is lower than the second reference voltage VT2, the temperature detection circuit 620 determines that the battery cell temperature is too low, and the logic circuit 630 outputs a charge prohibition control signal through its charge control terminal CO based on the determination result of the temperature detection circuit 620 to control the battery cell to prohibit charging. and / or the third reference voltage VT3 is greater than the fourth reference voltage VT4. When the temperature-sensitive voltage VR1 is higher than the third reference voltage VT3, the temperature detection circuit 620 determines that the temperature of the battery cell is too high, and the logic circuit outputs a prohibit discharge control signal through its discharge control terminal DO based on the determination result of the temperature detection circuit 620 to control the battery cell to prohibit discharge; when the temperature-sensitive voltage VR1 is lower than the fourth reference voltage VT4, the temperature detection circuit 620 determines that the temperature of the battery cell is too low, and the logic circuit 630 outputs a prohibit discharge control signal through its discharge control terminal DO based on the determination result of the temperature detection circuit 620 to control the battery cell to prohibit discharge.

[0041] The voltage detection circuit 640 and Figure 4 The voltage detection circuit 440 is consistent with the current detection circuit 650. Figure 4 The current detection circuit 450 is the same as that shown in FIG. Figure 4 The description of the voltage detection circuit 440 and the current detection circuit 450 is omitted here.

[0042] In a preferred embodiment, Figure 3 The thermal pad 322 connected to three metal wires is connected to the Figure 6 In a preferred embodiment, during layout design, the resistor R1 is placed below or near the thermal pad 322 connected to the three metal wires to enhance the thermal conductivity.

[0043] It should be noted that the temperature sensing circuit in the present invention can also be used Figure 4 、 Figure 5 and Figure 6 Other temperature sensing circuits other than the temperature sensing circuits 410 , 510 , and 610 shown in the figure may be used as long as they can provide a temperature-sensitive voltage EQ1 reflecting the temperature of the battery cell.

[0044] In the present invention, words such as “connect,” “connected,” “connect,” and “connected” that represent electrical connection, unless otherwise specified, represent direct or indirect electrical connection.

[0045] It should be noted that any changes made by those skilled in the art to the specific embodiments of the present invention do not depart from the scope of the claims of the present invention. Accordingly, the scope of the claims of the present invention is not limited to the aforementioned specific embodiments.

Claims

1. A battery protection chip with battery cell temperature detection, characterized in that: It includes: Encapsulation; a metal frame, a portion of which is exposed on the surface of the package of the battery protection chip; The battery protection chip located in the package includes a temperature sensing circuit, which conducts the heat of the battery cell into the battery protection chip through the metal frame so that the temperature measured by the temperature sensing circuit can reflect the temperature of the temperature detection point of the battery cell. A thermally conductive pad is provided on the battery protection wafer, and the metal frame is connected to the thermally conductive pad via a metal wire; The metal frame is a lead frame, which is used to carry the battery protection chip and realize the electrical connection between the internal circuit of the battery protection chip and the outside by means of packaging wires. The battery protection chip also includes a voltage detection circuit, a current detection circuit and a logic circuit. The voltage detection circuit is used to detect whether the cell voltage is abnormal during charging and discharging; The current detection circuit is used to detect whether the cell current is abnormal during charging and discharging; When the voltage detection circuit detects that the battery cell voltage is abnormal or the current detection circuit detects that the battery cell current is abnormal, the logic circuit outputs a charge prohibition control signal through its charge control terminal (CO) or outputs a discharge prohibition control signal through its discharge control terminal (DO) based on the detection results of the voltage detection circuit and the current detection circuit.

2. The battery protection chip with core temperature detection according to claim 1, characterized in that: The portion of the metal frame exposed to the surface of the package of the battery protection chip is placed close to the temperature detection point of the battery cell; or The surface of the battery protection wafer is coated with a thermal conductive material.

3. The battery protection chip with core temperature detection according to claim 1, characterized in that: The battery protection chip also includes a temperature detection circuit and a logic circuit. The input end of the temperature detection circuit is connected to the temperature sensing circuit, and the output end thereof is connected to the input end of the logic circuit. The temperature detection circuit determines whether the temperature of the battery cell is abnormal based on the temperature measured by the temperature sensing circuit; The logic circuit is used to output a charge prohibition control signal or a discharge prohibition control signal when the temperature detection circuit determines that the temperature of the battery cell is abnormal.

4. The battery protection chip with core temperature detection according to claim 3, characterized in that: The temperature sensing circuit outputs a temperature-sensitive voltage (EQ1) reflecting the temperature of the battery cell. The temperature-sensitive voltage (EQ1) is a negative temperature coefficient voltage. When the temperature-sensitive voltage (EQ1) is lower than the first reference voltage (VT1), the temperature detection circuit (420) determines that the battery cell temperature is too high, and the logic circuit outputs a charge prohibition control signal through its charge control terminal (CO) based on the determination result of the temperature detection circuit (420) to control the battery cell to prohibit charging; when the temperature-sensitive voltage (EQ1) is higher than the second reference voltage (VT2), the temperature detection circuit (420) determines that the battery cell temperature is too low, and the logic circuit (430) outputs a charge prohibition control signal through its charge control terminal (CO) based on the determination result of the temperature detection circuit (420) to control the battery cell to prohibit charging, wherein the first reference voltage (VT1) is lower than the second reference voltage (VT2); and / or When the temperature-sensitive voltage (EQ1) is lower than the third reference voltage (VT3), the temperature detection circuit (420) determines that the battery cell temperature is too high, and the logic circuit outputs a discharging prohibition control signal through its discharge control terminal (DO) based on the determination result of the temperature detection circuit (420) to control the battery cell to prohibit discharging; when the temperature-sensitive voltage (EQ1) is higher than the fourth reference voltage (VT4), the temperature detection circuit (420) determines that the battery cell temperature is too low, and the logic circuit (430) outputs a discharging prohibition control signal through its discharge control terminal (DO) based on the determination result of the temperature detection circuit (420) to control the battery cell to prohibit discharging, wherein the third reference voltage (VT3) is lower than the fourth reference voltage (VT4).

5. The battery protection chip with core temperature detection according to claim 4, characterized in that: The temperature sensing circuit comprises a first current source (I1) and a PNP transistor (Q1), wherein the input end of the first current source (I1) is connected to a power supply end (VDD), and the output end thereof is connected to the emitter of the PNP transistor (Q1); the base and collector of the PNP transistor (Q1) are both grounded; a connection node between the output end of the first current source (I1) and the emitter of the PNP transistor (Q1) provides a temperature-sensitive voltage (EQ1) reflecting the temperature of the battery cell, and the temperature-sensitive voltage (EQ1) is a negative temperature coefficient voltage; The emitter of the PNP transistor (Q1) is connected to a thermally conductive pad provided on the battery protection chip via metal; or The PNP transistor (Q1) is placed below or near a thermally conductive pad provided on the battery protection chip.

6. The battery protection chip with core temperature detection according to claim 5, characterized in that: The temperature detection circuit comprises a first comparator (Comp1) and a second comparator (Comp2), wherein the inverting input terminal of the first comparator (Comp1) is connected to the temperature-sensitive voltage (EQ1), the non-inverting input terminal thereof is connected to the first reference voltage (VT1), and the output terminal thereof is connected to the input terminal of the logic circuit (430); and the non-inverting input terminal of the second comparator (Comp2) is connected to the temperature-sensitive voltage (EQ1), the inverting input terminal thereof is connected to the second reference voltage (VT2), and the output terminal thereof is connected to the input terminal of the logic circuit (430).

7. The battery protection chip with core temperature detection according to claim 3, characterized in that: The temperature sensing circuit outputs a temperature-sensitive voltage (EQ1) reflecting the temperature of the battery cell. The temperature-sensitive voltage (EQ1) is a positive temperature coefficient voltage. When the temperature-sensitive voltage (EQ1) is higher than the first reference voltage (VT1), the temperature detection circuit (520) determines that the battery cell temperature is too high, and the logic circuit 530 outputs a charge prohibition control signal through its charge control terminal (CO) based on the determination result of the temperature detection circuit 520 to control the battery cell to prohibit charging; when the temperature-sensitive voltage (EQ1) is lower than the second reference voltage (VT2), the temperature detection circuit (520) determines that the battery cell temperature is too low, and the logic circuit 530 outputs a charge prohibition control signal through its charge control terminal (CO) based on the determination result of the temperature detection circuit (520) to control the battery cell to prohibit charging, wherein the first reference voltage (VT1) is greater than the second reference voltage (VT2); and / or When the temperature-sensitive voltage (EQ1) is higher than the third reference voltage (VT3), the temperature detection circuit (520) determines that the battery cell temperature is too high, and the logic circuit (530) outputs a discharge prohibition control signal through its discharge control terminal (DO) based on the determination result of the temperature detection circuit (520) to control the battery cell to prohibit discharge; when the temperature-sensitive voltage (EQ1) is lower than the fourth reference voltage (VT4), the temperature detection circuit (520) determines that the battery cell temperature is too low, and the logic circuit (530) outputs a discharge prohibition control signal through its discharge control terminal (DO) based on the determination result of the temperature detection circuit (520) to control the battery cell to prohibit discharge, wherein the third reference voltage (VT3) is greater than the fourth reference voltage (VT4).

8. The battery protection chip with core temperature detection according to claim 7, characterized in that: The temperature sensing circuit (510) comprises a first current source (I1), a second current source (I2), a first NPN transistor (Q1), a second NPN transistor (Q2) and a resistor (R1), wherein the input end of the first current source (I1) is connected to a power supply end (VDD), the output end thereof is connected to the collector of the first NPN transistor (Q1), the emitter of the first NPN transistor (Q1) is grounded via the resistor (R1), and the base of the first NPN transistor (Q1) is connected to the second NPN transistor. The base of the transistor (Q2) is connected to the input end of the second current source (I2) and the power supply end (VDD), and the output end thereof is connected to the collector of the second NPN transistor (Q2), the base of the second NPN transistor (Q2) is connected to its collector, and the emitter of the second NPN transistor (Q2) is grounded; the connection node between the emitter of the first NPN transistor (Q1) and the resistor (R1) provides the temperature-sensitive voltage (EQ1), and the temperature-sensitive voltage (EQ1) is a positive temperature coefficient voltage; The bases of the first NPN transistor (Q1) and the second NPN transistor (Q2) are connected to a thermally conductive pad provided on the battery protection chip via metal; or The first NPN transistor (Q1) and the second NPN transistor (Q2) are placed below or near a thermally conductive pad provided on the battery protection chip.

9. The battery protection chip with core temperature detection according to claim 7, characterized in that: The temperature sensing circuit (610) comprises a first current source (I1) and a resistor (R1), wherein the input end of the first current source (I1) is connected to a power supply end (VDD), and the output end thereof is grounded via the resistor (R1), and a connection node between the output end of the first current source (I1) and the resistor (R1) provides the temperature-sensitive voltage (VR1), and the temperature-sensitive voltage (VR1) is a positive temperature coefficient voltage; The resistor (R1) is connected to a thermally conductive pad provided on the battery protection chip through metal; or The resistor (R1) is placed below or near a thermally conductive pad provided on the battery protection wafer.

10. The battery protection chip with core temperature detection according to claim 8 or 9, characterized in that: The temperature detection circuit includes a first comparator (Comp1) and a second comparator (Comp2). The non-phase input terminal of the first comparator (Comp1) is connected to the temperature-sensitive voltage (EQ1), the inverting input terminal thereof is connected to the first reference voltage (VT1), and the output terminal thereof is connected to the input terminal of the logic circuit (530); The inverting input terminal of the second comparator (Comp2) is connected to the temperature-sensitive voltage (EQ1), the non-inverting input terminal thereof is connected to the second reference voltage (VT2), and the output terminal thereof is connected to the input terminal of the logic circuit (430).

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