Over-current detection circuit and battery

Abstract

The invention discloses an overcurrent detection circuit and a battery, and relates to the technical field of detection. The over-current detection circuit comprises an over-current detection module, a first voltage division module, a second voltage division module and a control module, the over-current detection module is arranged on a battery charging and discharging circuit, and the first voltage dividing module and the second voltage dividing module are connected in series and then connected to the two ends of the over-current detection module in parallel; the first voltage dividing module is a variable resistance voltage dividing module, and the second voltage dividing module is a fixed resistance voltage dividing module or a variable resistance voltage dividing module; the control module is electrically connected with the first voltage dividing module or the second voltage dividing module; the control module is configured to obtain the voltage of the first voltage dividing module or the voltage of the second voltage dividing module; and according to the voltage of the first voltage dividing module or the voltage of the second voltage dividing module, whether the battery charging and discharging loop is over-current is detected. And the problems of small application range, difficulty in implementation and high design cost of precision resistance measurement can be avoided.

Description

Technical Field

[0001] The present application relates to the field of detection technology, and in particular to an overcurrent detection circuit and a battery. Background Art

[0002] In order to meet user needs, most electronic products, such as mobile phones, currently hope that the battery can support fast charging. During fast charging, as the charging current increases, it is necessary to more accurately detect the high current in the circuit to prevent abnormal high current from causing the PCM function of the battery protection board to fail, or even the risk of thermal failure of the battery causing explosion.

[0003] Most existing detection schemes monitor the current of the charge and discharge circuit by detecting the voltage across the precision resistor. However, as the charging current increases, the package of the precision resistor also needs to be enlarged to meet the large current (the larger the resistor package, the greater its power). Therefore, this detection method has a small scope of application and is not easy to operate. In addition, the design cost of using precision resistors for current detection is relatively high. Summary of the invention

[0004] Purpose of the invention: An embodiment of the present application provides an overcurrent detection circuit, aiming to overcome the technical problems in the prior art of using precision resistors to measure current, which has a small application range, is difficult to operate, and has a high design cost; another purpose of the embodiment of the present application is to provide a battery.

[0005] Technical solution: An overcurrent detection circuit according to an embodiment of the present application is applied to a battery charging and discharging circuit, comprising: an overcurrent detection module, a first voltage dividing module, a second voltage dividing module and a control module; wherein the overcurrent detection module is arranged on the battery charging and discharging circuit, and the first voltage dividing module and the second voltage dividing module are connected in series and then in parallel at both ends of the overcurrent detection module;

[0006] Wherein, the first voltage divider module is a variable resistance voltage divider module, and the second voltage divider module is a fixed resistance voltage divider module or a variable resistance voltage divider module;

[0007] Among them, the control module is electrically connected to the first voltage divider module or the second voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module, or the voltage of the second voltage divider module.

[0008] In some embodiments, the first voltage divider module and the second voltage divider module are both variable resistance voltage divider modules; and the control module is electrically connected to the first voltage divider module or the second voltage divider module;

[0009] The control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module, or the voltage of the second voltage divider module.

[0010] In some embodiments, the first voltage divider module is a voltage divider module whose resistance value is inversely proportional to the temperature change, and the second voltage divider module is a voltage divider module whose resistance value is proportional to the temperature change; and the control module is electrically connected to the first voltage divider module;

[0011] The control module is configured to: obtain the voltage of the first voltage divider module, and detect whether the battery charging and discharging circuit has an overcurrent according to the voltage of the first voltage divider module.

[0012] In some embodiments, the first voltage divider module includes one or more first variable resistance voltage divider units connected in series and / or in parallel; the second voltage divider module includes one or more second variable resistance voltage divider units connected in series and / or in parallel.

[0013] In some embodiments, the first voltage divider module is a variable resistance voltage divider module, and the second voltage divider module is a fixed resistance voltage divider module; and the control module is electrically connected to the first voltage divider module or the second voltage divider module;

[0014] The control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module, or the voltage of the second voltage divider module.

[0015] In some embodiments, the first voltage divider module is a voltage divider module whose resistance is inversely proportional to the temperature change; and the control module is electrically connected to the first voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module.

[0016] In some embodiments, the first voltage divider module is a voltage divider module whose resistance is proportional to the temperature change; and the control module is electrically connected to the second voltage divider module; the control module is configured to: obtain the voltage of the second voltage divider module, and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the second voltage divider module.

[0017] In some embodiments, the first voltage divider module includes one or more third variable resistance voltage divider units connected in series and / or in parallel; the second voltage divider module includes one or more fixed resistance voltage divider units connected in series and / or in parallel.

[0018] In some embodiments, the voltage divider module whose resistance is inversely proportional to the temperature change is a negative temperature coefficient thermistor.

[0019] In some embodiments, the voltage divider module whose resistance is proportional to the temperature change is a positive temperature coefficient thermistor.

[0020] In some embodiments, the overcurrent detection module is copper foil.

[0021] Correspondingly, a battery described in an embodiment of the present application includes the overcurrent detection circuit as described above.

[0022] Beneficial effect: Compared with the prior art, the overcurrent detection circuit and battery of the embodiment of the present application, the overcurrent detection circuit is applied to the battery charging and discharging circuit, including: an overcurrent detection module, a first voltage divider module, a second voltage divider module and a control module; the overcurrent detection module is arranged on the battery charging and discharging circuit, and the first voltage divider module and the second voltage divider module are connected in series and then connected in parallel at both ends of the overcurrent detection module; wherein the first voltage divider module is a variable resistance voltage divider module, and the second voltage divider module is a fixed resistance voltage divider module or a variable resistance voltage divider module; wherein the control module is electrically connected to the first voltage divider module or the second voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent according to the voltage of the first voltage divider module, or the voltage of the second voltage divider module. By setting an overcurrent detection module in the battery charge and discharge circuit, and connecting a branch consisting of two voltage divider modules in series in parallel at both ends of the overcurrent detection module, during the battery charge and discharge process, especially when the current increases, since at least one of the two voltage divider modules is a voltage divider module with a variable resistance, when the current increases and the temperature rises, the voltage of the overcurrent detection module can be accurately detected by detecting the voltage of any voltage divider module, and then whether the battery charge and discharge circuit is overcurrent can be detected. Compared with the prior art, the problem of small application range, difficulty in implementation and high design cost of using precision resistance measurement can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a principle structure block diagram of an overcurrent detection circuit provided in an embodiment of the present application;

[0025] Figure 2 is a principle structure block diagram of another overcurrent detection circuit provided in an embodiment of the present application;

[0026] Figure 3 is a principle structure block diagram of another overcurrent detection circuit provided in an embodiment of the present application;

[0027] Figure 4 is a structural schematic diagram of an overcurrent detection circuit provided in an embodiment of the present application;

[0028] Figure 5 is a structural schematic diagram of another overcurrent detection circuit provided in an embodiment of the present application;

[0029] Figure 6 is a structural schematic diagram of another overcurrent detection circuit provided in an embodiment of the present application;

[0030] Figure 7 This is a schematic diagram of overcurrent detection wiring provided in an embodiment of the present application;

[0031] Figure 8 This is another overcurrent detection wiring diagram provided in an embodiment of the present application;

[0032] Fig. 9 This is another overcurrent detection wiring diagram provided in an embodiment of the present application;

[0033] Fig.10 This is another overcurrent detection wiring diagram provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0035] It should be understood that although the terms first, second, etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another component. Therefore, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of the present application. As used herein, the term "and / or" includes any one of the associated listed items and all combinations of one or more.

[0036] Those skilled in the art will appreciate that the drawings are only schematic diagrams of example embodiments and may not be to scale. The modules or processes in the drawings are not necessarily required to implement the present application and therefore cannot be used to limit the scope of protection of the present application.

[0037] Figure 1is a principle structure block diagram of an overcurrent detection circuit provided in an embodiment of the present application. Figure 1 The overcurrent detection circuit is applied to a battery charging and discharging circuit, and the overcurrent detection circuit comprises: an overcurrent detection module 10, a first voltage divider module 20, a second voltage divider module 30 and a control module 40; wherein, the overcurrent detection module 10 is arranged on the battery charging and discharging circuit, and the first voltage divider module 20 and the second voltage divider module 30 are connected in series and then connected in parallel at both ends of the overcurrent detection module 10; wherein, the first voltage divider module 20 is a variable resistance voltage divider module, and the second voltage divider module is a fixed resistance voltage divider module or a variable resistance voltage divider module; wherein, the control module 40 is electrically connected to the first voltage divider module 20 or the second voltage divider module 30; the control module 40 is configured to: obtain the voltage of the first voltage divider module 20, or the voltage of the second voltage divider module 30; and detect whether the battery charging and discharging circuit is overcurrent according to the voltage of the first voltage divider module 20, or the voltage of the second voltage divider module 30.

[0038] For example, taking a certain high current circuit in a battery charging and discharging circuit as an example, refer to Figure 1 The overcurrent detection module 10 is connected in series to the high current line 101 , and the first voltage dividing module 20 and the second voltage dividing module 30 are connected in series and then connected in parallel to both ends of the overcurrent detection module 10 .

[0039] Among them, at least one of the two voltage-dividing modules is a voltage-dividing module with a variable resistance. For example, the first voltage-dividing module 20 is a variable resistance voltage-dividing module, and the second voltage-dividing module is a fixed resistance voltage-dividing module or a variable resistance voltage-dividing module. Alternatively, the first voltage-dividing module 20 is a fixed resistance voltage-dividing module or a variable resistance voltage-dividing module, and the second voltage-dividing module 30 is a variable resistance voltage-dividing module. It can be specifically set according to actual conditions, and no specific limitation is made here. For example, the present application takes the first voltage-dividing module 20 as a variable resistance voltage-dividing module, and the second voltage-dividing module as a fixed resistance voltage-dividing module or a variable resistance voltage-dividing module as an example for explanation (the same below, no further description is given).

[0040] Among them, the control module can detect whether the battery charge and discharge circuit is overcurrent based on the voltage of any one of the two voltage divider modules. For example, when the control module is electrically connected to the first voltage divider module, the control module obtains the voltage of the first voltage divider module, and detects whether the battery charge and discharge circuit is overcurrent based on the voltage of the first voltage divider module. When the control module is electrically connected to the second voltage divider module, the control module obtains the voltage of the second voltage divider module, and detects whether the battery charge and discharge circuit is overcurrent based on the voltage of the second voltage divider module.

[0041] Among them, the control module detects whether the battery charge and discharge circuit is overcurrent according to the voltage of any one of the two voltage-dividing modules in the following implementation method: since the two voltage-dividing modules are connected in series and then connected in parallel with the overcurrent detection module, the voltage of the overcurrent detection module can be detected according to the voltage of any one of the two voltage-dividing modules. Then, according to the voltage and resistance value of the overcurrent detection module, combined with Ohm's law, the current of the battery charge and discharge circuit, such as the current of the high current circuit 101, can be calculated, and then it can be judged whether the battery charge and discharge circuit is overcurrent according to the preset overcurrent current.

[0042] Among them, the control module can be a battery management chip, a single-chip microcomputer or other control chip, which can be specifically set according to actual conditions and is not specifically limited here.

[0043] In the technical solution of this embodiment, the implementation process of the overcurrent detection circuit is as follows: Figure 1 , the overcurrent detection module 10 is arranged in series in a section of a high current line 101 of the battery charging and discharging circuit, and the series branches of the first voltage divider module 20 and the second voltage divider module 30 are connected in parallel to the two ends of the overcurrent detection module 10. Since there is at least one voltage divider module with a variable resistance value in the two voltage divider modules, when the current in the battery charging and discharging circuit increases and the temperature rises, the voltage divider ratio of the series branch can be adjusted through the two voltage divider modules, so that the voltage at both ends of the detected voltage divider module remains basically unchanged (it can be considered unchanged within the error allowable range), so only the voltage of any voltage divider module needs to be detected to accurately detect the current of the overcurrent detection module, and then it can be detected whether the battery charging and discharging circuit is overcurrent, so the overcurrent detection method is easy to implement and has strong applicability. Compared with the prior art, it can avoid the problems of small application scope, difficulty in implementation and high design cost caused by using precision resistors to measure overcurrent.

[0044] Based on the above embodiments, optionally, the first voltage divider module and the second voltage divider module are both variable resistance voltage divider modules; and the control module is electrically connected to the first voltage divider module or the second voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module, or the voltage of the second voltage divider module.

[0045] Among them, both voltage-dividing modules are variable resistance voltage-dividing modules. Among them, one voltage-dividing module is a voltage-dividing module whose resistance is proportional to the temperature change, and the other voltage-dividing module is a voltage-dividing module whose resistance is inversely proportional to the temperature change, and the control module is electrically connected to the voltage-dividing module whose resistance is inversely proportional to the temperature change. For example, if the first voltage-dividing module is a voltage-dividing module whose resistance is proportional to the temperature change, then the second voltage-dividing module is a voltage-dividing module whose resistance is inversely proportional to the temperature change, and at this time the control module is electrically connected to the second voltage-dividing module. Alternatively, the first voltage-dividing module is a voltage-dividing module whose resistance is inversely proportional to the temperature change, and the second voltage-dividing module is a voltage-dividing module whose resistance is proportional to the temperature change, and at this time the control module is electrically connected to the first voltage-dividing module. It can be specifically set according to the actual situation, and no specific limitation is made here.

[0046] In the technical solution of this embodiment, the implementation process of the overcurrent detection circuit is as follows: the overcurrent detection module is set in series in a section of the high current line 101 of the battery charging and discharging circuit, and two variable resistance voltage divider modules are connected in series and then connected in parallel to the two ends of the overcurrent detection module 10. Since both voltage divider modules are variable resistance voltage divider modules, and one of the voltage divider modules is a voltage divider module whose resistance is proportional to the temperature change, and the other voltage divider module is a voltage divider module whose resistance is inversely proportional to the temperature change, when the current in the battery charging and discharging circuit increases and the temperature rises, the voltage divider ratio of the series branch can be adjusted through the two variable resistance voltage divider modules, so that the voltage at both ends of the voltage divider module whose resistance is inversely proportional to the temperature change remains basically unchanged, so only the voltage of the voltage divider module whose resistance is inversely proportional to the temperature change needs to be detected to accurately detect the current of the overcurrent detection module, and then whether the battery charging and discharging circuit is overcurrent can be detected, so the overcurrent detection method is easy to implement and has strong applicability. Compared with the prior art, it can avoid the problems of small application scope, difficulty in implementation and high design cost caused by using precision resistors to measure overcurrent.

[0047] As an implementation mode, optionally, taking the first voltage divider module as a voltage divider module whose resistance is inversely proportional to the temperature change, and the second voltage divider module as a voltage divider module whose resistance is directly proportional to the temperature change as an example, the control module is electrically connected to the first voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module.

[0048] Specifically, the overcurrent detection module is arranged in series in a section of a high current line 101 of the battery charging and discharging circuit, and two variable resistance voltage divider modules are connected in series and then connected in parallel to the two ends of the overcurrent detection module 10. Since the first voltage divider module is a voltage divider module whose resistance is inversely proportional to the temperature change, and the second voltage divider module is a voltage divider module whose resistance is directly proportional to the temperature change, when the current in the battery charging and discharging circuit increases and the temperature rises, the resistance of the voltage divider module whose resistance is inversely proportional to the temperature change decreases as the temperature rises, which will suppress the voltage rise of the voltage divider module whose resistance is inversely proportional to the temperature change, and increase the voltage rise of the voltage divider module whose resistance is directly proportional to the temperature change, so that the voltage at both ends of the voltage divider module whose resistance is inversely proportional to the temperature change remains basically unchanged, so that the current at both ends of the overcurrent detection module can be accurately detected by detecting the voltage at both ends of the voltage divider module whose resistance is inversely proportional to the temperature change. And because the resistance of the voltage divider module whose resistance is proportional to the temperature change increases with the temperature increase, the voltage rise of the voltage divider module whose resistance is inversely proportional to the temperature change can be further suppressed, and the voltage rise of the voltage divider module whose resistance is proportional to the temperature change can be increased, so that the voltage at both ends of the voltage divider module whose resistance is inversely proportional to the temperature change is basically maintained unchanged. Thus, the voltage divider ratio of the series branch can be well adjusted through these two variable resistance voltage divider modules, so that the voltage at both ends of the voltage divider module whose resistance is inversely proportional to the temperature change is basically maintained unchanged, so that only the voltage of the first voltage divider module needs to be detected to accurately detect the current of the overcurrent detection module during the battery charging and discharging process, and then it can be detected whether the battery charging and discharging circuit is overcurrent, so the overcurrent detection method is easy to implement and has strong applicability. And compared with the prior art, it can avoid the problems of small application scope, difficulty in implementation and high design cost caused by using precision resistors to measure current.

[0049] Based on the above embodiments, optionally, the first voltage divider module includes one or more first variable resistance voltage divider units connected in series and / or in parallel; the second voltage divider module includes one or more second variable resistance voltage divider units connected in series and / or in parallel.

[0050] Among them, in the first variable resistance voltage divider unit and the second variable resistance voltage divider unit, one voltage divider unit is a voltage divider unit whose resistance value is proportional to the temperature change, and the other voltage divider unit is a voltage divider unit whose resistance value is inversely proportional to the temperature change, and wherein, a voltage divider module composed of a voltage divider unit whose resistance value is inversely proportional to the temperature change, or a plurality of voltage dividers whose resistance value is inversely proportional to the temperature change are connected in series and / or in parallel is electrically connected to the control module. For example, if the first variable resistance voltage divider unit is a voltage divider unit whose resistance value is proportional to the temperature change, then the second variable resistance voltage divider unit is a voltage divider unit whose resistance value is inversely proportional to the temperature change, and at this time, a second variable resistance voltage divider unit, or a voltage divider module composed of a plurality of second variable resistance voltage dividers connected in series and / or in parallel is electrically connected to the control module. Alternatively, the first variable resistance voltage divider unit is a voltage divider unit whose resistance is inversely proportional to the temperature change, and the second voltage divider module is a voltage divider unit whose resistance is proportional to the temperature change, and a voltage divider module composed of a first variable resistance voltage divider unit, or a plurality of first variable resistance voltage dividers connected in series and / or in parallel, is electrically connected to the control module. The specific configuration can be based on actual conditions and is not specifically limited here.

[0051] Figure 2 : is a principle structure block diagram of another overcurrent detection circuit provided in an embodiment of the present application. For example, taking the first variable resistance voltage divider unit as a voltage divider unit whose resistance is inversely proportional to the temperature change, and the second variable resistance voltage divider unit as a voltage divider unit whose resistance is proportional to the temperature change, Figure 2 The embodiment shows that the first voltage divider module is formed by connecting a plurality of first variable resistance voltage divider units in series, and the second voltage divider module is formed by connecting a plurality of second variable resistance voltage divider units in series. Figure 2The first voltage divider module 20 is formed by connecting the first variable resistance voltage divider unit A RB11, the first variable resistance voltage divider unit B RB12 and the first variable resistance voltage divider unit C RB13 in series, and the second voltage divider module 30 is formed by connecting the second variable resistance voltage divider unit A RB21, the second variable resistance voltage divider unit B RB22 and the second variable resistance voltage divider unit C RB23 in series. In addition, the first voltage divider module formed by connecting the first variable resistance voltage divider unit A RB11, the first variable resistance voltage divider unit B RB12 and the first variable resistance voltage divider unit C RB13 in series is electrically connected to the control module 40. Since the first voltage-dividing module is a voltage-dividing module whose resistance value is inversely proportional to the temperature change, and the second voltage-dividing module is a voltage-dividing module whose resistance value is proportional to the temperature change, when the current in the battery charging and discharging circuit increases and the temperature rises, the resistance value of the voltage-dividing module whose resistance value is inversely proportional to the temperature change decreases with the temperature rise, which will suppress the voltage rise of the voltage-dividing module whose resistance value is inversely proportional to the temperature change, increase the voltage rise of the voltage-dividing module whose resistance value is inversely proportional to the temperature change, so that the voltage at both ends of the voltage-dividing module whose resistance value is inversely proportional to the temperature change remains basically unchanged, thereby accurately detecting the current at both ends of the overcurrent detection module by detecting the voltage at both ends of the voltage-dividing module whose resistance value is inversely proportional to the temperature change. And since the resistance value of the voltage-dividing module whose resistance value is inversely proportional to the temperature change increases with the temperature rise, the voltage rise of the voltage-dividing module whose resistance value is inversely proportional to the temperature change can be further suppressed, and the voltage rise of the voltage-dividing module whose resistance value is inversely proportional to the temperature change can be increased, so that the voltage at both ends of the voltage-dividing module whose resistance value is inversely proportional to the temperature change remains basically unchanged. Thus, the voltage-dividing ratio of the series branch can be well adjusted through the two variable resistance voltage-dividing modules, so that the voltage at both ends of the voltage-dividing module whose resistance is inversely proportional to the temperature change remains basically unchanged, so only the voltage of the first voltage-dividing module needs to be detected to accurately detect the current of the overcurrent detection module during the battery charging and discharging process, and then it can be detected whether the battery charging and discharging circuit is overcurrent, so the overcurrent detection method is easy to implement and has strong applicability. Compared with the prior art, it can avoid the problems of small application scope, difficulty in implementation and high design cost caused by using precision resistors to measure current.

[0052] As an implementation mode, optionally, taking the first voltage divider module as a variable resistance voltage divider module and the second voltage divider module as a fixed resistance voltage divider module as an example, the control module can be electrically connected to the first voltage divider module or the second voltage divider module. The control module is configured to: obtain the voltage of the first voltage divider module or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent according to the voltage of the first voltage divider module or the voltage of the second voltage divider module.

[0053] Among them, one of the two voltage divider modules is a voltage divider module with a variable resistance value, and the other is a voltage divider module with a fixed resistance value. Among them, the first voltage divider module can be a voltage divider module with a variable resistance value, or a voltage divider module with a fixed resistance value. Similarly, the second voltage divider module is also. It can be set according to actual conditions, and no specific limitation is made here.

[0054] It should be noted that, in the technical solution of this embodiment, the voltage-dividing module with a variable resistance value can be a voltage-dividing module whose resistance value is inversely proportional to the temperature change or a voltage-dividing module whose resistance value is proportional to the temperature change. Furthermore, when the voltage-dividing module with a variable resistance value is a voltage-dividing module whose resistance value is inversely proportional to the temperature change, the control module is electrically connected to the voltage-dividing module with a variable resistance value, and by obtaining the voltage of the voltage-dividing module with a variable resistance value, it is possible to detect whether the battery charging and discharging circuit is overcurrent. When the voltage-dividing module with a variable resistance value is a voltage-dividing module whose resistance value is proportional to the temperature change, the control module is electrically connected to the voltage-dividing module with a fixed resistance value, and by obtaining the voltage of the voltage-dividing module with a fixed resistance value, it is possible to detect whether the battery charging and discharging circuit is overcurrent. The specific settings can be made according to the actual situation, and no specific limitation is made here.

[0055] As a specific implementation, optionally, the first voltage divider module is a voltage divider module whose resistance is inversely proportional to the temperature change; and the control module is electrically connected to the first voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module.

[0056] Specifically, the overcurrent detection module is arranged in series in a section of a high current line 101 of the battery charging and discharging circuit, and the first voltage divider module and the second voltage divider module are connected in series and then connected in parallel to the two ends of the overcurrent detection module 10. Since the first voltage divider module is a voltage divider module whose resistance is inversely proportional to the temperature change, and the second voltage divider module is a voltage divider module with a fixed resistance, when the current in the battery charging and discharging circuit increases and the temperature rises, the resistance of the voltage divider module whose resistance is inversely proportional to the temperature change decreases with the increase in temperature, thereby suppressing the voltage rise of the voltage divider module whose resistance is inversely proportional to the temperature change, and increasing the voltage rise of the voltage divider module with a fixed resistance, so that the voltage at both ends of the voltage divider module whose resistance is inversely proportional to the temperature change remains basically unchanged, and thus only the voltage of the voltage divider module whose resistance is inversely proportional to the temperature change needs to be detected to accurately detect the current of the overcurrent detection module during the battery charging and discharging process, and further, whether the battery charging and discharging circuit is overcurrent can be accurately detected, so the overcurrent detection method is easy to implement and has strong applicability. Compared with the prior art, the present invention can avoid the problems of small application scope, difficulty in implementation and high design cost caused by using precision resistors to measure current.

[0057] As a specific implementation, optionally, the first voltage divider module is a voltage divider module whose resistance is proportional to the temperature change; and the control module is electrically connected to the second voltage divider module; the control module is configured to: obtain the voltage of the second voltage divider module, and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the second voltage divider module.

[0058] Specifically, the overcurrent detection module is arranged in series in a high current line 101 of the battery charging and discharging circuit, and the first voltage divider module and the second voltage divider module are connected in series and then connected in parallel to the two ends of the overcurrent detection module 10. Since the first voltage divider module is a voltage divider module whose resistance is proportional to the temperature change, and the second voltage divider module is a voltage divider module with a fixed resistance, when the current in the battery charging and discharging circuit increases and the temperature rises, the voltage rise of the voltage divider module with a fixed resistance value will be suppressed, and the voltage rise of the voltage divider module with a resistance proportional to the temperature change will be increased, so that the voltage at both ends of the voltage divider module with a fixed resistance value remains basically unchanged, so only the voltage of the voltage divider module with a fixed resistance value needs to be detected to accurately detect the current of the overcurrent detection module during the battery charging and discharging process, and then whether the battery charging and discharging circuit is overcurrent can be detected, so the overcurrent detection method is easy to implement and has strong applicability. Compared with the prior art, it can avoid the problems of small application scope, difficulty in implementation and high design cost caused by using precision resistors to measure current.

[0059] Based on the above embodiments, optionally, the first voltage divider module includes one or more third variable resistance voltage divider units connected in series and / or in parallel; the second voltage divider module includes one or more fixed resistance voltage divider units connected in series and / or in parallel.

[0060] Wherein, the third variable resistance voltage divider unit can be a voltage divider unit whose resistance value is inversely proportional to the temperature change, or a voltage divider unit whose resistance value is proportional to the temperature change. Moreover, when the third variable resistance voltage divider unit is a voltage divider unit whose resistance value is inversely proportional to the temperature change, at this time, a voltage divider module composed of a voltage divider unit whose resistance value is inversely proportional to the temperature change, or a plurality of voltage dividers whose resistance value is inversely proportional to the temperature change are connected in series and / or in parallel is electrically connected to the control module. When the third variable resistance voltage divider unit is a voltage divider unit whose resistance value is proportional to the temperature change, at this time, a fixed resistance voltage divider unit, or a plurality of fixed resistance voltage dividers connected in series and / or in parallel is electrically connected to the control module.

[0061] Figure 3 : is a principle structure block diagram of another overcurrent detection circuit provided in an embodiment of the present application. For example, taking the third variable resistance voltage divider unit as a voltage divider unit whose resistance is proportional to the temperature change as an example, Figure 3The embodiment shows that the first voltage divider module is formed by connecting a plurality of third variable resistance voltage divider units in series, and the second voltage divider module is formed by connecting a plurality of fixed resistance voltage divider units in series and in parallel. Figure 3 The first voltage divider module 20 is composed of a third variable resistance voltage divider unit A RB31, a third variable resistance voltage divider unit B RB32 and a third variable resistance voltage divider unit C RB33 connected in series, and the second voltage divider module 30 is composed of a first resistor R1 and a second resistor R2 connected in parallel and connected in series with a third resistor R3. In addition, the first end of the third resistor R3 is electrically connected to the control module 40, and the first end of the first resistor R1 and the first end of the second resistor R2 are electrically connected to the control module 40, that is, the control module is electrically connected to the second voltage divider module 30. Since the first voltage divider module is a voltage divider module whose resistance is proportional to the temperature change, and the second voltage divider module is a voltage divider module with a fixed resistance value, when the current in the battery charging and discharging circuit increases and the temperature rises, the voltage rise of the voltage divider module with a resistance proportional to the temperature change will be suppressed due to the increase in the resistance of the voltage divider module with a resistance proportional to the temperature change, and the voltage rise of the voltage divider module with a resistance proportional to the temperature change will be increased, so that the voltage at both ends of the voltage divider module with a fixed resistance value remains basically unchanged, and thus only the voltage of the voltage divider module with a fixed resistance value needs to be detected to accurately detect the current of the overcurrent detection module during the battery charging and discharging process, and then whether the battery charging and discharging circuit is overcurrent can be detected, so the overcurrent detection method is easy to implement and has strong applicability. Compared with the prior art, it can avoid the problems of small application scope, difficulty in implementation and high design cost caused by using precision resistors to measure current.

[0062] Optionally, the voltage divider module whose resistance value is inversely proportional to the temperature change is a negative temperature coefficient thermistor.

[0063] The specific parameter selection of the negative temperature coefficient thermistor can be set according to the actual situation, and no specific limitation is made here. Optionally, the voltage divider module whose resistance is proportional to the temperature change is a positive temperature coefficient thermistor.

[0064] Among them, the specific parameter selection of the positive temperature coefficient thermistor can be set according to actual conditions, and no specific limitation is made here.

[0065] In addition, the voltage divider module whose resistance is proportional to the temperature change can also be a thermal resistor, a thermocouple, etc., which can be specifically set according to actual conditions and is not specifically limited here.

[0066] Optionally, the voltage divider module with a fixed resistance is a fixed resistance.

[0067] The resistance of the fixed resistor can be set according to actual conditions and is not specifically limited here.

[0068] In addition, the voltage divider module with a fixed resistance value may also be a voltage divider, etc., which may be specifically configured according to actual conditions and is not specifically limited here.

[0069] Optionally, the overcurrent detection module is copper foil.

[0070] Specifically, by using copper foil to replace the precision resistor in the prior art, on the one hand, the design cost can be reduced, and on the other hand, by connecting the copper foil in series in the high current circuit of the battery charging and discharging circuit, and connecting two voltage divider modules in series and then in parallel at both ends of the copper foil, and by detecting the voltage of any of the voltage divider modules, it is possible to determine whether the battery charging and discharging circuit is overcurrent. Therefore, the problem that the prior art uses precision resistors to measure overcurrent, which leads to an increase in the precision resistor package and increases the package size of the battery protection circuit module (PCM), thereby reducing the size of the battery body, which is not conducive to increasing the battery capacity, can be solved.

[0071] Figure 4 is a schematic diagram of the structure of an overcurrent detection circuit provided in an embodiment of the present application. For example, taking the first voltage divider module as a negative temperature coefficient thermistor RT1 and the second voltage divider module as a positive temperature coefficient thermistor RT2 as an example, refer to Figure 4 Taking the control module as the battery management chip U1 as an example, the copper foil T0 is connected in series in the battery charging and discharging circuit, the negative temperature coefficient thermistor RT1 and the positive temperature coefficient thermistor RT2 are connected in series and then connected in parallel at both ends of the copper foil T0, and the negative temperature coefficient thermistor RT1 is electrically connected to the battery management chip U1. The battery management chip U1 detects whether the battery charging and discharging circuit is overcurrent by detecting the voltage at both ends of the negative temperature coefficient thermistor RT1, and when overcurrent is detected, the switch tube Q1 is controlled to be turned off to disconnect the battery charging and discharging circuit, thereby protecting the circuit.

[0072] Figure 5 1 is a schematic diagram of another overcurrent detection circuit provided in an embodiment of the present application. For example, the first voltage divider module is a negative temperature coefficient thermistor RT1, and the second voltage divider module is a voltage divider resistor with a fixed resistance, such as a common fixed value resistor R0. Figure 5 Taking the control module as the battery management chip U1 as an example, the copper foil T0 is connected in series in the battery charging and discharging circuit, the negative temperature coefficient thermistor RT1 and the ordinary fixed value resistor R0 are connected in series and then connected in parallel at both ends of the copper foil T0, and the negative temperature coefficient thermistor RT1 is electrically connected to the battery management chip U1. The battery management chip U1 detects whether the battery charging and discharging circuit is overcurrent by detecting the voltage at both ends of the negative temperature coefficient thermistor RT1, and when overcurrent is detected, the switch tube Q1 is controlled to be closed to disconnect the battery charging and discharging circuit, thereby protecting the circuit.

[0073] Figure 61 is a schematic diagram of another overcurrent detection circuit provided in an embodiment of the present application. For example, the first voltage divider module is a positive temperature coefficient thermistor RT2, and the second voltage divider module is a fixed resistance resistor, such as a common fixed resistance resistor R0. Figure 6 Taking the control module as the battery management chip U1 as an example, the copper foil T0 is connected in series in the battery charging and discharging circuit, the positive temperature coefficient thermistor RT2 and the ordinary fixed resistor R0 are connected in series and then connected in parallel at both ends of the copper foil T0, and the ordinary fixed resistor R0 is electrically connected to the battery management chip U1. The battery management chip U1 detects whether the battery charging and discharging circuit is overcurrent by detecting the voltage across the ordinary fixed resistor R0, and when overcurrent is detected, it controls the switch tube Q1 to be turned off to disconnect the battery charging and discharging circuit, thereby protecting the circuit.

[0074] It should be noted that the above embodiment is described by setting a section of copper foil in a battery charging and discharging circuit, connecting two branches in series of two voltage divider modules in parallel at both ends of the copper foil, and an overcurrent detection device corresponding to a control module for voltage detection. In addition, the embodiment of the present application can also be configured as follows: setting a section of copper foil in the same battery charging and discharging circuit, and setting two sets of the above-mentioned overcurrent detection devices at both ends of the same section of copper foil. Figure 7 is a wiring diagram of an overcurrent detection provided in an embodiment of the present application, Figure 8 is another overcurrent detection wiring diagram provided in the embodiment of the present application. Figure 7 The first set of overcurrent detection equipment includes a negative temperature coefficient thermistor NTC1, a resistor R11, a control module 1 (such as a driver chip IC1) and a copper foil 1, and the second set of overcurrent detection equipment includes a negative temperature coefficient thermistor NTC2, a resistor R12, a control module 2 (such as a driver chip IC2) and a copper foil 1. The two sets of equipment share the same copper foil 1, and their common overcurrent detection point can be Figure 7 The overcurrent detection point 1 shown can also be Figure 8 The overcurrent detection point 2 shown can be set according to actual conditions, and no specific limitation is made here. The advantage of setting a section of copper foil in the same battery charging and discharging circuit and setting two sets of the above-mentioned overcurrent detection devices at both ends of the same section of copper foil is that it can be used for redundant design on the one hand and for mutual verification on the other hand to ensure the accuracy of overcurrent detection. Among them, the redundant design can be applied to, for example, the redundant design when the safety test fails.

[0075] The embodiment of the present application can also be configured as follows: two sections of copper foil connected in series are arranged in the same battery charge and discharge circuit, and a set of the above-mentioned overcurrent detection device is respectively connected in parallel to both ends of each section of copper foil. Fig. 9 is another overcurrent detection wiring diagram provided in the embodiment of the present application. Fig. 9The first set of overcurrent detection equipment includes a negative temperature coefficient thermistor NTC1, a resistor R11, a control module 1 (such as a driver chip IC1) and a copper foil 1. The second set of overcurrent detection equipment includes a negative temperature coefficient thermistor NTC2, a resistor R12, a control module 2 (such as a driver chip IC2) and a copper foil 2. The driver chip IC1 is Fig. 9 The over-current detection point 1 and over-current detection point 2 in the drive chip IC2 are detected by Fig. 9 The over-current detection point 3 and the over-current detection point 4 are detected. This setting can be used for: scenarios with different over-current detection requirements, and the specific judgment standard of the over-current threshold can be set according to the actual situation, and no specific limitation is made here.

[0076] For example, during installation design, copper foil can be placed on the surface of high current circuits, for example, Figures 7 to 9 The setting is adopted, and the branch of the two voltage divider modules in series is designed close to the copper foil, so that the temperature change of the copper foil can be better detected.

[0077] Fig.10 This is another overcurrent detection wiring diagram provided in the embodiment of the present application. In addition, the copper foil can also be designed in the inner PCB through-current circuit, for example, in the form of copper foil or via installation, for example, Fig.10 The via hole method shown in the figure is used, and the voltage divider module is arranged above the copper foil. Among them, the via hole design can simplify the layout, optimize the space, increase the volume of the battery body, and help to improve the battery capacity.

[0078] Exemplarily, the voltage detection accuracy estimation method of the implementation scheme of the present application is as follows: Among them, the resistance of the copper foil can be set according to the actual situation, and no specific limitation is made here. Assuming that the current of the battery charging and discharging circuit is I, the resistance of the overcurrent detection copper foil is R (copper), assuming that the corresponding copper foil resistance at room temperature of 25°C is 2mΩ, the temperature drift of the copper foil is about 3930PPM (the internal resistance of the copper foil increases with the increase of temperature), and the temperature range of the product is -20°C-60°C, then the voltage drop generated at both ends of the copper foil can be calculated as:

[0079] U=I*R(copper)=I*R(25)*(T-25)*3930PPM

[0080] And when there is no branch formed by the two voltage divider modules in series connected in parallel at both ends of the copper foil, the lower limit tolerance of voltage detection is: A = ((-20)-25)*3930PPM*100% = -17.7%, and the upper limit tolerance of voltage detection is: B = (60-25)*3930PPM = 13.8%. Therefore, the total tolerance range is: BA = 13.8% - (17.7%) = 31.5%.

[0081] When the first voltage divider module is a negative temperature coefficient thermistor RT1 and the second voltage divider module is a common fixed value resistor R0, the resistance of the negative temperature coefficient thermistor RT1 at room temperature T0=20°C is 10K (wherein, the corresponding relationship between the resistance value and temperature of the negative temperature coefficient thermistor RT1 is shown in Table 1).

[0082] Assuming that the resistance of the common fixed value resistor R0 is 1KΩ, according to the series-parallel relationship, the voltage U(measured) across the negative temperature coefficient thermistor RT1 is: U(measured) = RT2 / (RT2+R7)*U = RT2 / (RT2+R7)*I*R(copper). Therefore, the corresponding voltage detection lower limit tolerance is: A2 = RT2(-20℃) / (RT2(-20℃)+R7)*A = 67.96 / (67.96+1)*(-17.7%) = -17.4%, and the voltage upper limit tolerance is: B2 = RT2(60℃) / (RT2(60℃)+R7)*B = 3.086 / (3.086+1)*(13.8%) = 10.4%, and the total tolerance range is: B2-A2 = 10.4%-(17.4%) = 27.8%. Compared with the case where the two voltage divider modules are not connected in parallel at both ends of the copper foil to form a branch in series, the tolerance range is reduced by: (31.5%-27.8%) / 31.5%=11.7%. Therefore, when the negative temperature coefficient thermistor is connected in parallel at both ends of the copper foil, its resistance decreases as the temperature rises. By matching the design of ordinary fixed value resistors, the change of the detection voltage affected by the change of the internal resistance of the copper foil with the temperature can be suppressed, thereby improving the accuracy of overcurrent detection. Similarly, according to the above-mentioned accuracy estimation method, the detection accuracy can be estimated when the first voltage divider module is a negative temperature coefficient thermistor RT1 and the second voltage divider module is a positive temperature coefficient thermistor RT2, and when the first voltage divider module is a positive temperature coefficient thermistor RT2 and the second voltage divider module is an ordinary fixed value resistor. It will not be repeated here.

[0083] Table 1 Corresponding relationship between resistance and temperature of negative temperature coefficient thermistor RT1

[0084] Temp Min Nom Max (degC) (k ohm) (k ohm) (k ohm) -20 65.84 67.79 69.79 -15 52.05 53.46 54.91 -10 41.42 42.45 43.5 -5 33.18 33.93 34.69 0 26.74 27.28 27.83 5 21.68 22.07 22.47 10 17.68 17.96 18.25 15 14.49 14.7 14.9 20 11.95 12.09 12.24 25 9.9 10 10.1 30 8.213 8.312 8.41 35 6.848 6.942 7.037 40 5.736 5.826 5.916 45 4.827 4.911 4.996 50 4.081 4.158 4.237 55 3.464 3.536 3.609 60 2.953 3.019 3.086

[0085] An embodiment of the present application also provides a battery, which includes the overcurrent detection circuit provided by any embodiment of the present application.

[0086] The battery may be a lithium battery or the like, and may be configured specifically according to actual conditions, and is not specifically limited here.

[0087] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0088] The overcurrent detection circuit and battery provided in the embodiments of the present application are introduced in detail above, and the principles and implementation methods of the present application are explained by using specific examples. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application; ordinary technicians in this field should understand that: they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. An overcurrent detection circuit, applied to a battery charging and discharging circuit, characterized in that: include: An overcurrent detection module, a first voltage division module, a second voltage division module and a control module; wherein the overcurrent detection module is arranged on the battery charging and discharging circuit, and the first voltage division module and the second voltage division module are connected in series and then in parallel at both ends of the overcurrent detection module; Wherein, the first voltage divider module is a variable resistance voltage divider module, and the second voltage divider module is a fixed resistance voltage divider module or a variable resistance voltage divider module; Among them, the control module is electrically connected to the first voltage divider module or the second voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module, or the voltage of the second voltage divider module.

2. The overcurrent detection circuit according to claim 1, characterized in that: The first voltage dividing module and the second voltage dividing module are both variable resistance voltage dividing modules; and the control module is electrically connected to the first voltage dividing module or the second voltage dividing module; The control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module, or the voltage of the second voltage divider module.

3. The overcurrent detection circuit according to claim 2, characterized in that: The first voltage divider module is a voltage divider module whose resistance value is inversely proportional to the temperature change, and the second voltage divider module is a voltage divider module whose resistance value is directly proportional to the temperature change; and the control module is electrically connected to the first voltage divider module; The control module is configured to: obtain the voltage of the first voltage divider module, and detect whether the battery charging and discharging circuit has an overcurrent according to the voltage of the first voltage divider module.

4. The overcurrent detection circuit according to claim 2, characterized in that: The first voltage dividing module includes one or more first variable resistance voltage dividing units connected in series and / or in parallel; the second voltage dividing module includes one or more second variable resistance voltage dividing units connected in series and / or in parallel.

5. The overcurrent detection circuit according to claim 1, characterized in that: The first voltage divider module is a variable resistance voltage divider module, and the second voltage divider module is a fixed resistance voltage divider module; and the control module is electrically connected to the first voltage divider module or the second voltage divider module; The control module is configured to: obtain the voltage of the first voltage divider module, or the voltage of the second voltage divider module; and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module, or the voltage of the second voltage divider module.

6. The overcurrent detection circuit according to claim 5, characterized in that: The first voltage divider module is a voltage divider module whose resistance is inversely proportional to the temperature change; and the control module is electrically connected to the first voltage divider module; the control module is configured to: obtain the voltage of the first voltage divider module, and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the first voltage divider module.

7. The overcurrent detection circuit according to claim 5, characterized in that: The first voltage divider module is a voltage divider module whose resistance is proportional to the temperature change; and the control module is electrically connected to the second voltage divider module; the control module is configured to: obtain the voltage of the second voltage divider module, and detect whether the battery charging and discharging circuit is overcurrent based on the voltage of the second voltage divider module.

8. The overcurrent detection circuit according to claim 5, characterized in that: The first voltage dividing module includes one or more third variable resistance voltage dividing units connected in series and / or in parallel; the second voltage dividing module includes one or more fixed resistance voltage dividing units connected in series and / or in parallel.

9. The overcurrent detection circuit according to claim 3 or 6, characterized in that: The voltage divider module whose resistance value is inversely proportional to the temperature change is a negative temperature coefficient thermistor.

10. The overcurrent detection circuit according to claim 3 or 7, characterized in that: The voltage divider module whose resistance value is proportional to the temperature change is a positive temperature coefficient thermistor.

11. The overcurrent detection circuit according to claim 1, characterized in that: The overcurrent detection module is copper foil.

12. A battery, characterized in that: The invention comprises an overcurrent detection circuit as claimed in any one of claims 1 to 11.

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