Battery protection system with cell temperature detection

Abstract

The present invention provides a battery protection system with cell temperature detection, comprising: a battery protection chip including several pins and a temperature sensor; a thermal conductive sheet located outside the battery protection chip, with one end of the thermal conductive sheet adjacent to the pins of the battery protection chip and the other end adjacent to the battery cell. Heat from the battery cell is conducted into the battery protection chip via the thermal conductive sheet and the pins, so that the temperature measured by the temperature sensor reflects the temperature at the cell's temperature detection point. This invention can add cell temperature detection functionality without increasing the number of chip pins, thereby facilitating chip miniaturization and reducing chip application costs.

Description

Technical field

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

[0002] In the design of battery protection chips, the design of battery cell temperature detection function can further improve the safety of the battery. Figure 1 As shown, this is a circuit diagram of a battery protection system in the prior art. It can provide charging overvoltage protection, discharging overvoltage protection, discharging overcurrent protection, and charging overcurrent protection for three battery cells connected in series. By sampling the voltage difference between chip pins (or nodes) V1 and GND, the first battery cell BAT1 can be protected from charging overvoltage and discharging overvoltage. By sampling the voltage difference between chip pins V2 and V1, the second battery cell BAT2 can be protected from charging overvoltage and discharging overvoltage. By sampling the voltage difference between chip pins V3 and V2, the third battery cell BAT3 can be protected from charging overvoltage and discharging overvoltage. By sampling the voltage difference between chip pins VL and GND (which indirectly samples the charging and discharging currents, (VL-VGND) / R is the discharge current, and (VGND-VL) / R is the charging current, where VGND is the voltage of chip pin GND, VL is the voltage of chip pin VL, and R is the resistance value of resistor Rs), discharge overcurrent protection and charging overcurrent protection can be implemented. Traditionally, some products have adopted packages with more pins, such as 10, to add cell temperature sensing functionality. The additional pins may require a larger package size (to accommodate the increased pin count), increasing chip costs. Larger packages also occupy more printed circuit board area, hindering miniaturization.

[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 system with cell temperature detection, which can add the function of cell temperature detection without increasing chip pins, thereby facilitating chip miniaturization design and reducing chip application costs.

[0005] According to one aspect of the present invention, the present invention proposes a battery protection system with battery cell temperature detection, which includes: a battery protection chip, which includes a plurality of pins and a temperature sensor; a thermal conductive sheet, which is located outside the battery protection chip, and one end of the thermal conductive sheet is close to the pins of the battery protection chip, and the other end of the thermal conductive sheet is close to the battery cell, wherein the heat of the battery cell is introduced into the interior of the battery protection chip through the thermal conductive sheet and the pins, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cell.

[0006] Compared with the prior art, the present invention is provided with a thermal conductive sheet located outside the battery protection chip. The heat of the battery cell is introduced into the battery protection chip through the thermal conductive sheet and the pins, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cell. In this way, the function of battery cell temperature detection can be increased without increasing the chip pins, which is conducive to the miniaturization design of the chip and reduces the chip application cost.

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 1 This is a circuit diagram of a battery protection system in the prior art;

[0009] Figure 2 This is a circuit diagram of a battery protection system with cell temperature detection in a first embodiment of the present invention;

[0010] Figure 3 This is a circuit diagram of a battery protection system with cell temperature detection in a second embodiment of the present invention;

[0011] Figure 4 Schematic diagram of a circuit of a battery protection system with cell temperature detection according to a third embodiment of the present invention;

[0012] Figure 5 In one embodiment of the present invention, Figure 2-Figure 4 The circuit diagram of the battery protection chip shown;

[0013] Figure 6 The figure is a circuit diagram of a temperature sensor designed based on a MOS transistor in one 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 present invention provides a battery protection system with battery cell temperature detection, which includes a battery protection chip and a thermal conductive sheet. The battery protection chip includes a plurality of pins and a temperature sensor; the thermal conductive sheet is located outside the battery protection chip, with one end of the thermal conductive sheet close to the pins of the battery protection chip and the other end close to the battery cell, wherein the heat of the battery cell is introduced into the interior of the battery protection chip through the thermal conductive sheet and the pins, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cell. In this way, the present invention can increase the function of battery cell temperature detection without increasing the number of chip pins, thereby facilitating chip miniaturization design and reducing chip application costs.

[0017] Please refer to Figure 2 As shown, it is a circuit diagram of a battery protection system with core temperature detection in the first embodiment of the present invention. Figure 2 In the illustrated embodiment, only the battery protection system with battery cell temperature detection is shown for three battery cells BAT1 , BAT2 and BAT3 connected in series. In other embodiments, the number of battery cells may be 1, 2, 4 or more.

[0018] Figure 2 The battery protection system with cell temperature detection shown includes a battery protection chip 210, a thermal pad 223, a charging power switch 240, a discharging power switch 230, resistors R1, R2, R3, and Rs, and capacitors C1, C2, and C3. The battery protection chip 210 includes pins V1, V2, V3, GND, VL, VM, DO, and CO, and a temperature sensor (not shown). Pins V1, V2, V3, GND, VL, and VM are called connection terminals or detection terminals; pins DO and CO are called control terminals.

[0019] Thermal pad 223 is located outside the battery protection chip 210, with one end of the pad near pin V3 of the battery protection chip 210 and the other end near battery cells BAT1, BAT2, and BAT3. Thermal pad 223, as indicated by the black fill area, can be designed on a printed circuit board. Thermal pad 223 can be made of metal or other composite materials with good thermal conductivity. In some applications, flexible materials with good thermal conductivity may be used. The principle is as follows: the heat conducting sheet (or a large piece of heat conducting material) 223 conducts heat from a position close to the battery cells BAT1, BAT2 and BAT3, and conducts it to the inside of the battery protection chip 210 through the chip pin V3 (that is, the heat of the battery cells BAT1, BAT2, BAT3 is introduced into the battery protection chip 210 through the heat conducting sheet 223 and the pin V3), and then the temperature is sensed by the temperature sensor (not shown) inside the battery protection chip 210, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cells BAT1, BAT2, BAT3, and notify the corresponding circuit to realize battery temperature detection (including one or more combinations of the following functions: prohibiting charging at high temperature, prohibiting charging at low temperature, prohibiting discharging at high temperature, and prohibiting discharging at low temperature).

[0020] The battery cells BAT1, BAT2 and BAT3 are connected in series between the positive electrode BP+ of the battery and the ground terminal; the resistor R3 is connected between the positive electrode of the battery cell BAT3 and the pin V3, and the resistor C3 is connected between the pin V3 and the ground terminal; the resistor R2 is connected between the positive electrode of the battery cell BAT2 and the pin V2, and the resistor C2 is connected between the pin V2 and the ground terminal; the resistor R1 is connected between the positive electrode of the battery cell BAT1 and the pin V1, and the resistor C1 is connected between the pin V1 and the ground terminal; the pin GND is connected to the negative electrode of the battery cell BAT1; and the pin VM is connected to the negative electrode BP- of the battery.

[0021] The charging power switch 240 includes an NMOS (N-Metal-Oxide-Semiconductor) field-effect transistor MC and a parasitic diode (not shown) within it. The discharging power switch 230 includes an NMOS field-effect transistor MD and a parasitic diode (not shown) within it. The drains of the NMOS field-effect transistors MD and MC are connected; the source of the NMOS field-effect transistor MD is connected to the negative electrode of the battery cell BAT1 via a resistor Rs; the source of the NMOS field-effect transistor MC is connected to the negative electrode BP- of the battery; the pin VL is connected to the connection node between the NMOS field-effect transistor MD and the resistor Rs; the pin CO (i.e., the charging control terminal CO) is connected to the control terminal of the charging power switch 240 (i.e., the gate of the NMOS field-effect transistor MC), and the pin DO (i.e., the discharging control terminal DO) is connected to the control terminal of the discharging power switch 230 (i.e., the gate of the NMOS field-effect transistor MD).

[0022] The battery protection chip 210 can perform charging overvoltage protection and discharging overvoltage protection on the battery cell BAT1 by sampling the voltage difference between the chip pin (or node) V1 and GND, and can perform charging overvoltage protection and discharging overvoltage protection on the battery cell BAT2 by sampling the voltage difference between the chip pins V2 and V1. The battery protection chip 210 can perform charging overvoltage protection and discharging overvoltage protection on the battery cell BAT3 by sampling the voltage difference between the chip pins V3 and V2. The battery protection chip 210 can implement discharge overcurrent protection and charge overcurrent protection by sampling the voltage difference between the chip pins VL and GND (indirectly sampling the charging current and discharging current, (VL-VGND) / R is the discharge current, (VGND-VL) / R is the charging current, where VGND is the voltage of the chip pin GND, VL is the voltage of the chip pin VL, and R is the resistance value of the resistor Rs).

[0023] Please refer to Figure 3 , which is a circuit diagram of a battery protection system with cell temperature detection in a second embodiment of the present invention. Figure 3 The battery protection system with cell temperature detection shown includes a battery protection chip 210, thermal conductive sheets 221-223, a charging power switch 240, a discharging power switch 230, resistors R1, R2, R3, and Rs, and capacitors C1, C2, and C3. Figure 3 and Figure 2 The circuit structure is basically the same as Figure 2 compared to, Figure 3 A heat conducting sheet 222 is placed near the pin V2 , and a heat conducting sheet 221 is placed near the pin V1 .

[0024] The thermal conductive sheets 221 and 222 are located outside the battery protection chip 210, with one end of the thermal conductive sheet 221 close to pin V1 of the battery protection chip 210 and the other end close to the battery cells BAT1, BAT2, and BAT3. One end of the thermal conductive sheet 222 is close to pin V2 of the battery protection chip 210, and the other end close to the battery cells BAT1, BAT2, and BAT3. The thermal conductive sheets 221 and 222 are shown in the black filled areas and can be designed on a printed circuit board. The thermal conductive sheets 221 and 222 can be made of metal or other composite materials with good thermal conductivity. In some applications, flexible materials with good thermal conductivity can be used.

[0025] In one embodiment, Figure 3 The principle shown may be: the thermally conductive sheet (or large piece of thermally conductive material) 221 conducts heat from a position close to the battery cells BAT1, BAT2 and BAT3, and conducts it to the inside of the battery protection chip 210 through the chip pin V1; the thermally conductive sheet (or large piece of thermally conductive material) 222 conducts heat from a position close to the battery cells BAT1, BAT2 and BAT3, and conducts it to the inside of the battery protection chip 210 through the chip pin V2; or the thermally conductive sheet (or large piece of thermally conductive material) 223 conducts heat from a position close to the battery cells BAT1, BAT2 and BAT3, and conducts it to the inside of the battery protection chip 210 through the chip pin V3. That is to say, the heat of the battery cells BAT1, BAT2 and BAT3 is introduced into the battery protection chip 210 through the thermal conductive sheet 221 and the pin V1, through the thermal conductive sheet 222 and the pin V2, or through the thermal conductive sheet 223 and the pin V3, and then the temperature is sensed by the temperature sensor (not shown) inside the battery protection chip 210, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cells BAT1, BAT2, BAT3, and notify the corresponding circuit to realize battery temperature detection (including one or more combinations of the following functions: prohibiting charging at high temperature, prohibiting charging at low temperature, prohibiting discharging at high temperature, and prohibiting discharging at low temperature).

[0026] In another embodiment, Figure 3The principle shown may be: one end of the thermal conductive sheet 221 is close to the pin V1 of the battery protection chip 210, and the other end of the thermal conductive sheet 221 is close to the battery cell BAT1. The heat of the battery cell BAT1 is introduced into the first area inside the battery protection chip 210 through the thermal conductive sheet 221 and the pin V1, and then the temperature is sensed by a temperature sensor (not shown) located in the first area, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cell BAT1; one end of the thermal conductive sheet 222 is close to the pin V2 of the battery protection chip 210, and the other end of the thermal conductive sheet 222 is close to the battery cell BAT2. The heat of the battery cell BAT2 is introduced into the first area inside the battery protection chip 210 through the thermal conductive sheet 222 and the pin V1. V2 is introduced into the second area inside the battery protection chip 210, and then the temperature is sensed by a temperature sensor (not shown) located in the second area, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cell BAT2; one end of the thermal conductive sheet 223 is close to the pin V3 of the battery protection chip 210, and the other end of the thermal conductive sheet 223 is close to the battery cell BAT3. The heat of the battery cell BAT3 is introduced into the third area inside the battery protection chip 210 through the thermal conductive sheet 223 and the pin V3, and then the temperature is sensed by a temperature sensor (not shown) located in the third area, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cell BAT2. That is to say, the thermal conductive sheet 221 and the pin V1 are used to transfer the temperature of the battery cell BAT1 to the first area inside the battery protection chip 210; the thermal conductive sheet 222 and the pin V2 are used to transfer the temperature of the battery cell BAT2 to the second area inside the battery protection chip 210; the thermal conductive sheet 223 and the pin V3 are used to transfer the temperature of the battery cell BAT3 to the third area inside the battery protection chip 210. Three different temperature sensors are placed in these three different areas inside the battery protection chip 210 to detect the temperature information of the three different battery cells BAT1, BAT2, and BAT3 respectively, so that temperature detection can be performed on the three battery cells BAT1, BAT2, and BAT3 (including one or more combinations of the following functions: prohibiting charging at high temperature, prohibiting charging at low temperature, prohibiting discharging at high temperature, and prohibiting discharging at low temperature).

[0027] based on Figure 3 As can be seen from the embodiment shown, in a specific embodiment of the present invention, there are a plurality of battery cells; there are a plurality of thermal conductive sheets, and one end of each thermal conductive sheet is close to the corresponding pin in the battery protection chip, and the other end of the thermal conductive sheet is close to the corresponding battery cell; there are a plurality of temperature sensors, and the plurality of temperature sensors are respectively located in different areas within the battery protection chip;

[0028] The heat of each battery cell is introduced into the area corresponding to the battery cell in the battery protection chip through a heat conducting sheet close to the battery cell and a pin close to the heat conducting sheet, so that the temperature measured by the temperature sensor located in the area can reflect the temperature of the temperature detection point of the battery cell, thereby realizing temperature detection of several battery cells.

[0029] Please refer to Figure 4 , which is a circuit diagram of a battery protection system with cell temperature detection in a third embodiment of the present invention. Figure 4 The battery protection system with cell temperature detection shown includes a battery protection chip 210, thermal conductive sheets 221-228, a charging power switch 240, a discharging power switch 230, resistors R1, R2, R3, and Rs, and capacitors C1, C2, and C3. Figure 4 and Figure 2 The circuit structure is basically the same as Figure 2 compared to, Figure 4 A heat conducting sheet 221 to 228 is placed near each pin V1, V2, V3, GND, VL, VM, DO, and CO. These heat conducting sheets 221 to 228 can be extended to the position where temperature detection is required, and multiple pins and multiple heat conducting sheets can be used to simultaneously conduct heat to a temperature sensor inside the battery protection chip 210 to enhance the effect of heat conduction. For example, a heat conducting sheet 223 near pin V3 and a heat conducting sheet 225 near pin DO can be used to simultaneously conduct heat from the temperature detection point of the battery cell BAT3 to a temperature sensor inside the battery protection chip 210, thereby achieving a better effect than using only pin V3 and heat conducting sheet 223 to conduct heat. In other words, one or more heat conducting sheets can be used in combination to conduct heat from the same temperature detection point to the same temperature sensor.

[0030] based on Figure 4 As can be seen from the embodiment shown, in a specific embodiment of the present invention, each battery cell is close to n heat conducting sheets; the n heat conducting sheets are respectively close to n different pins of the battery protection chip;

[0031] The heat of each battery cell is introduced into the area corresponding to the battery cell in the battery protection chip through n thermal conductive sheets close to the battery cell and n different pins close to the n thermal conductive sheets, so that the temperature measured by the temperature sensor located in the area can reflect the temperature of the temperature detection point of the battery cell, and n is a natural number greater than or equal to 1, thereby improving the thermal conductivity effect.

[0032] Please refer to Figure 5 As shown, it is an embodiment of the present invention as shown in Figure 2-Figure 4 The circuit diagram of the battery protection chip is shown. Figure 5The battery protection chip shown includes a temperature sensor 510, an analog-to-digital converter 520, a logic module 530, a voltage detection module 540, a current detection module 550, a first driver 560, and a second driver 570. The input of the analog-to-digital converter 520 is connected to the output of the temperature sensor 510, and the output of the analog-to-digital converter 520 is connected to the input of the logic module 530. The input of the voltage detection module 540 is connected to pins V1, V2, V3, V4, and GND of the battery protection chip 210, and its output is connected to the input of the logic module 530. The input of the current detection module 550 is connected to pins VL and GND of the battery protection chip 210, and its output is connected to the input of the logic module 530. The first output of the logic module 530 is connected to pin CO of the battery protection chip 210, and the second output is connected to pin DO of the battery protection chip 210.

[0033] The temperature sensor 510 senses temperature and converts the temperature information into a voltage signal. The analog-to-digital converter 520 converts the voltage signal into a digital signal and outputs it to the logic module 530. The logic module 530 analyzes the temperature code based on the digital signal to determine whether the temperature of the battery cells BAT1, BAT2, and BAT3 is abnormal. If the temperature of the battery cells BAT1, BAT2, and BAT3 is abnormal, the logic module 530 outputs a charge disable control signal to pin CO through its first output terminal or outputs a discharge disable control signal to pin DO through its second output terminal.

[0034] In one embodiment, determining whether the temperature of the battery cells BAT1, BAT2, and BAT3 is abnormal includes one or more combinations of the following:

[0035] Determine whether the temperature of the battery cells BAT1, BAT2, and BAT3 is too high to prohibit charging;

[0036] Determine whether the temperature of the battery cells BAT1, BAT2, and BAT3 is too low to prohibit charging;

[0037] Determine whether the temperature of the battery cells BAT1, BAT2, and BAT3 is too high to prohibit discharge;

[0038] It is determined whether the temperature of the battery cells BAT1 , BAT2 , and BAT3 is low enough to prohibit discharge.

[0039] For example, when the temperature code exceeds a high-temperature charge-inhibit temperature code threshold, the logic module 530 sets pin CO to a low level (i.e., the logic module 530 outputs a charge-inhibit control signal to pin CO via its first output terminal), thereby implementing a charge-inhibit function. When the temperature code exceeds a high-temperature discharge-inhibit temperature code threshold, the logic module 530 sets pin DO to a low level (i.e., the logic module 530 outputs a discharge-inhibit control signal to pin DO via its second output terminal), thereby implementing a discharge-inhibit function. When the temperature code is lower than a low-temperature charge-inhibit temperature code threshold, the logic module 530 sets pin CO to a low level (i.e., the logic module 530 outputs a charge-inhibit control signal to pin CO via its first output terminal), thereby implementing a charge-inhibit function. When the temperature code is lower than a low-temperature discharge-inhibit temperature code threshold, the logic module 530 sets pin DO to a low level (i.e., the logic module 530 outputs a discharge-inhibit control signal to pin DO via its second output terminal), thereby implementing a discharge-inhibit function.

[0040] A first driver 560 is connected between the first output terminal of the logic module 530 and the pin CO. The function of the first driver 560 is to enhance the output driving capability of the charge control signal outputted from the pin CO. A second driver 570 is connected between the second output terminal of the logic module 530 and the pin DO. The function of the second driver 570 is to enhance the output driving capability of the discharge control signal outputted from the pin DO.

[0041] The voltage detection module 540 is used to detect abnormal voltages of the battery cells BAT1, BAT2, and BAT3 during charging and discharging. For example, by sampling the voltage difference between chip pin (or node) V1 and GND, the battery cell BAT1 can be tested for over-charge and over-discharge voltages; by sampling the voltage difference between chip pins V2 and V1, the battery cell BAT2 can be tested for over-charge and over-discharge voltages; and by sampling the voltage difference between chip pins V3 and V2, the battery cell BAT3 can be tested for over-charge and over-discharge voltages.

[0042] The current detection module 550 is used to detect whether there are any abnormal currents in the battery cells BAT1, BAT2, and BAT3 during charging and discharging. For example, by sampling the voltage difference between the chip pins VL and GND (indirectly sampling the charging and discharging currents, (VL-VGND) / R is the discharge current, and (VGND-VL) / R is the charging current, where VGND is the voltage of the chip pin GND, VL is the voltage of the chip pin VL, and R is the resistance value of resistor Rs), discharge overcurrent detection and charge overcurrent detection can be implemented.

[0043] When the voltage detection module 540 detects that the voltage of the battery cells BAT1, BAT2, and BAT3 is abnormal or the current detection module 550 detects that the current of the battery cells BAT1, BAT2, and BAT3 is abnormal, the logic module 530 outputs a charge prohibition control signal to the pin CO through its first output terminal or outputs a discharge prohibition control signal to the pin DO through its second output terminal based on the detection results of the voltage detection module 540 and the current detection module 550.

[0044] The temperature sensor 510 can be designed based on a positive temperature coefficient resistor, a negative temperature coefficient resistor, a bipolar transistor, or a MOS tube. Figure 6 As shown, it is a circuit diagram of a temperature sensor designed based on a MOS tube in one embodiment of the present invention. Figure 6 The temperature sensor shown includes a PMOS transistor MP1, a PMOS transistor MP2, an NMOS transistor MN1, an NMOS transistor MN2 and a resistor R4.

[0045] The source of the PMOS transistor MP1 is connected to the first output terminal TV1 of the temperature sensor, and the gate of the PMOS transistor MP1 is connected to the drain of the PMOS transistor MP1. The resistor R4 is connected between the first output terminal TV1 and the second output terminal TV2 of the temperature sensor. The source of the PMOS transistor MP2 is connected to the second output terminal TV2 of the temperature sensor, and the gate of the PMOS transistor MP2 is connected to the gate of the PMOS transistor MP1. The drain of the NMOS transistor MN1 is connected to the drain of the PMOS transistor MP1, and the gate of the NMOS transistor MN1 is grounded. The drain of the NMOS transistor MN2 is connected to the drain of the PMOS transistor MP2, the gate of the NMOS transistor MN2 is connected to the source of the NMOS transistor MN2, the gate of the NMOS transistor MN2 is connected to the gate of the PMOS transistor MP1, and the drain of the NMOS transistor MN2 is grounded.

[0046] If the PMOS transistors MP1 and MP2 are designed to operate in the subthreshold region, and their current density ratio is designed to be greater than 1 (i.e., the current density of the PMOS transistor MP1 is greater than that of the PMOS transistor MP2), in one embodiment, the NMOS transistors MN1 and MN2 can be designed to form a 1:1 current flow. Then, the width-to-length ratio of the PMOS transistor MP1 is designed to be smaller than that of the PMOS transistor MP2. This can achieve a current density greater than that of the PMOS transistor MP2. The difference in Vgs (gate-source voltage) between the PMOS transistors MP1 and MP2 is proportional to their temperatures, thus reflecting temperature information. The voltage across resistor R4 is exactly equal to the difference in gate-source voltage between the PMOS transistors MP1 and MP2. The analog-to-digital converter 520 detects the voltage difference between the first output terminal TV1 and the first output terminal TV2 of the temperature sensor and converts it into a temperature code, which can identify the temperature information.

[0047] 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.

[0048] 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 system with battery cell temperature detection, characterized in that: It includes: battery cells; A battery protection chip, which includes several pins and a temperature sensor; A heat conducting sheet is located outside the battery protection chip, with one end of the heat conducting sheet close to the pin of the battery protection chip and the other end of the heat conducting sheet close to the battery cell. The heat of the battery cell is introduced into the battery protection chip through the heat conducting sheet and the pin, so that the temperature measured by the temperature sensor can reflect the temperature of the temperature detection point of the battery cell. The battery protection chip further includes an analog-to-digital converter, a logic module, a voltage detection module, and a current detection module, wherein the input end of the analog-to-digital converter is connected to the output end of the temperature sensor, and the output end of the analog-to-digital converter is connected to the input end of the logic module; the input end of the voltage detection module is connected to the corresponding pin of the battery protection chip, and the output end thereof is connected to the input end of the logic module; the input end of the current detection module is connected to the corresponding pin of the battery protection chip, and the output end thereof is connected to the input end of the logic module; the first output end of the logic module is connected to pin CO of the battery protection chip, and the second output end thereof is connected to pin DO of the battery protection chip. The voltage detection module is used to detect whether the cell voltage is abnormal during charging and discharging; The current detection module is used to detect whether the current of the battery cell is abnormal during charging and discharging.

2. The battery protection system with core temperature detection according to claim 1, characterized in that: There are several battery cells; There are a plurality of heat conducting sheets, and one end of each heat conducting sheet is close to the corresponding pin of the battery protection chip, and the other end of the heat conducting sheet is close to the corresponding battery cell; There are multiple temperature sensors, and the multiple temperature sensors are respectively located in different areas of the battery protection chip; The heat of each battery cell is introduced into the area corresponding to the battery cell in the battery protection chip through a heat conducting sheet close to the battery cell and a pin close to the heat conducting sheet, so that the temperature measured by the temperature sensor located in the area can reflect the temperature of the temperature detection point of the battery cell.

3. The battery protection system with core temperature detection according to claim 2, characterized in that: Each battery cell has n thermal conductive sheets close to it; The n heat conducting sheets are respectively close to n different pins of the battery protection chip; The heat of each battery cell is introduced into the area corresponding to the battery cell in the battery protection chip through n thermal conductive plates close to the battery cell and n different pins close to the n thermal conductive plates, so that the temperature measured by the temperature sensor located in the area can reflect the temperature of the temperature detection point of the battery cell, and n is a natural number greater than or equal to 1.

4. The battery protection system with core temperature detection according to claim 1, characterized in that: The heat conducting sheet is arranged on the printed circuit board; The heat conducting sheet is made of metal material or a composite material with good thermal conductivity.

5. The battery protection system with core temperature detection according to any one of claims 1 to 4, characterized in that: The temperature sensor is used to sense temperature and convert temperature information into a voltage signal; The analog-to-digital converter is used to convert the voltage signal into a digital signal and output the digital signal to the logic module; The logic module performs temperature code analysis based on the digital signal to determine whether the temperature of the battery cell is abnormal, and when it is determined that the temperature of the battery cell is abnormal, outputs a charge prohibition control signal to pin CO through its first output end or outputs a discharge prohibition control signal to pin DO through its second output end.

6. The battery protection system with core temperature detection according to claim 5, characterized in that: Determining whether the temperature of the battery cell is abnormal includes one or more combinations of the following: Determining whether the temperature of the battery cell is too high to prohibit charging; Determining whether the temperature of the battery cell is too low to prohibit charging; Determining whether the temperature of the battery cell is too high to prohibit discharge; Determine whether the temperature of the battery cell is too low to prohibit discharge.

7. The battery protection system with core temperature detection according to claim 6, characterized in that: When the temperature code exceeds the high temperature charging prohibition temperature code threshold, the logic module outputs a charging prohibition control signal to the pin CO through its first output terminal; When the temperature code exceeds the high temperature discharging prohibition temperature code threshold, the logic module outputs a discharging prohibition control signal to the pin DO through its second output terminal; When the temperature code is lower than the low temperature charging prohibition temperature code threshold, the logic module outputs a charging prohibition control signal to the pin CO through its first output terminal; When the temperature code is lower than the low-temperature discharge prohibition temperature code threshold, the logic module outputs a discharge prohibition control signal to the pin DO through its second output terminal.

8. The battery protection system with core temperature detection according to claim 1, characterized in that: The temperature sensor includes a PMOS transistor MP1, a PMOS transistor MP2, an NMOS transistor MN1, an NMOS transistor MN2 and a resistor R4. The source of the PMOS transistor MP1 is connected to the first output terminal TV1 of the temperature sensor, and the gate of the PMOS transistor MP1 is connected to the drain of the PMOS transistor MP1. The resistor R4 is connected between the first output terminal TV1 and the second output terminal TV2 of the temperature sensor. The source of the PMOS transistor MP2 is connected to the second output terminal TV2 of the temperature sensor, and the gate of the PMOS transistor MP2 is connected to the gate of the PMOS transistor MP1. The drain of the NMOS transistor MN1 is connected to the drain of the PMOS transistor MP1, and the gate of the NMOS transistor MN1 is grounded. The drain of the NMOS transistor MN2 is connected to the drain of the PMOS transistor MP2, the gate of the NMOS transistor MN2 is connected to the source of the NMOS transistor MN2, the gate of the NMOS transistor MN2 is connected to the gate of the PMOS transistor MP1, and the drain of the NMOS transistor MN2 is grounded.

9. The battery protection system with core temperature detection according to claim 8, characterized in that: Design the PMOS transistors MP1 and MP2 to operate in the subthreshold region; The current density of the PMOS transistor MP1 is designed to be greater than the current density of the PMOS transistor MP2.

10. The battery protection system with core temperature detection according to claim 5, characterized in that: The battery protection chip further includes: a first driver connected between the first output terminal of the logic module and the pin CO, wherein the function of the first driver is to enhance the output driving capability of the charging control signal output by the pin CO; The second driver is connected between the second output terminal of the logic module and the pin DO. The function of the second driver is to enhance the output driving capability of the discharge control signal output by the pin DO.

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