Secondary battery to dry cell conversion circuit and battery module

Abstract

This utility model discloses a conversion circuit and battery module for converting rechargeable batteries to dry batteries. It includes a charging voltage detection circuit that outputs a first detection signal when the charging voltage output by the charging device is less than the battery voltage of the secondary battery management circuit; a boost circuit connected to a reference voltage receiver, the charging voltage detection circuit, and the charging device, which boosts the charging voltage based on the first detection signal and the reference voltage output by the reference voltage receiver, outputting a boosted voltage; a secondary battery management circuit connected to the boost circuit and the charging device, which charges based on either the boosted voltage or the charging voltage during charging and outputs a first voltage during discharging; and a buck circuit connected to the secondary battery management circuit, which reduces the first voltage during discharging, outputting a second voltage. This technical solution can adapt to charging devices with different charging voltages, improving the applicability of the rechargeable battery to dry battery conversion circuit.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a conversion circuit and battery module for converting secondary batteries to dry batteries. Background Technology

[0002] Dry cell batteries have a wide range of applications in daily life. With the advancement of technology, rechargeable batteries have higher energy efficiency, are safer, and are reusable compared to dry cell batteries. To facilitate their use in charging dry cell batteries, devices that convert rechargeable batteries to dry cell batteries have emerged.

[0003] like Figure 1 This is a basic structural block diagram of an existing secondary battery to dry cell battery conversion device. The existing device basically consists of three parts: a charger module, a step-down module, and a secondary battery module. The charger module is the charging end for the secondary battery, primarily for its recyclability, charging and storing energy when the battery is low. The secondary battery module is the power supply end for the load, storing energy and powering subsequent loads. The step-down module mainly converts the secondary battery voltage to a lower voltage to achieve its application in dry cell battery scenarios. However, during the charging process, this device can only charge the secondary battery if it can provide a sufficiently high voltage charger, failing to consider the low-voltage chargers available on the market, thus exhibiting a certain selectivity in its charger compatibility. Utility Model Content

[0004] This utility model provides a conversion circuit and battery module for converting secondary batteries to dry batteries, in order to solve the problem of poor applicability of existing secondary battery to dry battery application devices.

[0005] A conversion circuit for converting a secondary battery to a dry cell battery includes a charging voltage detection circuit, a boost circuit, a secondary battery management circuit, and a buck circuit.

[0006] The charging voltage detection circuit is connected to the secondary battery management circuit and is used to connect to the charging device. When the charging voltage output by the charging device is less than the battery voltage of the secondary battery management circuit, the circuit outputs a first detection signal.

[0007] The boost circuit is connected to the reference voltage receiving terminal, the charging voltage detection circuit and the charging device, and is used to boost the charging voltage according to the reference voltage and the first detection signal, and output the boost voltage.

[0008] The secondary battery management circuit is connected to the boost circuit and the charging device, and is used to charge according to the boost voltage or the charging voltage during charging, and to output a first voltage during discharging;

[0009] The step-down circuit is connected to the secondary battery management circuit and is used to step down the first voltage and output a second voltage when the secondary battery management circuit is discharging.

[0010] Furthermore, the boost circuit includes a first inductor, a first switching transistor, a second switching transistor, a driving circuit, a first comparator, a first capacitor, and a first voltage divider circuit;

[0011] The first terminal of the first inductor is connected to the charging device, the second terminal of the first inductor is connected to the first terminal of the first switching transistor and the second terminal of the second switching transistor, the second terminal of the first switching transistor is connected to the first terminal of the first capacitor, the second terminal of the first capacitor is grounded, and the first terminal of the second switching transistor is grounded.

[0012] The first terminal of the first voltage divider circuit is connected to the second terminal of the first switching transistor and the first terminal of the first capacitor. The second terminal of the first voltage divider circuit is grounded. The third terminal of the first voltage divider circuit is connected to the non-inverting input terminal of the first comparator. The inverting input terminal of the first comparator is connected to the reference voltage receiving terminal, which is used to feed back the boosted voltage to the first comparator.

[0013] The output of the first comparator is connected to the driving circuit and is used to output a first comparison signal to the driving circuit based on the reference voltage and the feedback boost voltage.

[0014] The driving circuit is connected to the third terminal of the first switching transistor, the third terminal of the second switching transistor, and the charging voltage detection circuit, and is used to control the first switching transistor and the second switching transistor to work according to the first detection signal and the first comparison signal.

[0015] Furthermore, the first switch is a PMOS transistor; the second switch is an NMOS transistor.

[0016] Furthermore, the first voltage divider circuit includes a first resistor and a second resistor connected in series; the connection node between the first resistor and the second resistor is connected to the non-inverting input terminal of the first comparator.

[0017] Furthermore, the secondary battery management circuit includes a charging control circuit and a secondary battery;

[0018] The charging control circuit is connected to the boost circuit, the charging device and the secondary battery, and is used to control the charging current of the secondary battery according to the battery voltage of the secondary battery.

[0019] The secondary battery is connected to the charging voltage detection circuit and the step-down circuit, and is used to charge according to the charging current during charging and to output the first voltage during discharging.

[0020] Furthermore, the charging control circuit includes a fifth switching transistor and a main control circuit;

[0021] The first terminal of the fifth switching transistor is connected to the boost circuit, and the second terminal of the fifth switching transistor is connected to the secondary battery management circuit.

[0022] The main control circuit is connected to the secondary battery management circuit and the third terminal of the fifth switching transistor, and is used to control the operation of the fifth switching transistor according to the battery voltage of the secondary battery management circuit.

[0023] Furthermore, the step-down circuit includes a second inductor, a third switching transistor, a fourth switching transistor, a switching transistor control circuit, a second capacitor, and a second voltage divider circuit;

[0024] The first terminal of the third switch is connected to the secondary battery management circuit, the second terminal of the third switch is connected to the second terminal of the fourth switch, and the first terminal of the fourth switch is grounded.

[0025] The first end of the second inductor is connected to the second end of the third switch and the second end of the fourth switch, the second end of the second inductor is connected to the first end of the second capacitor, and the second end of the second capacitor is grounded.

[0026] The first terminal of the second voltage divider circuit is connected to the second terminal of the second inductor and the first terminal of the second capacitor. The second terminal of the second voltage divider circuit is grounded. The third terminal of the second voltage divider circuit is connected to the switching transistor control circuit and is used to feed back the second voltage to the switching transistor control circuit.

[0027] The switching control circuit is connected to the third terminal of the third switching transistor and the third terminal of the fourth switching transistor, and is used to control the operation of the third switching transistor and the fourth switching transistor according to the feedback of the second voltage.

[0028] Furthermore, the third switch is a PMOS transistor; the fourth switch is an NMOS transistor.

[0029] Furthermore, the second voltage divider circuit includes a third resistor and a fourth resistor connected in series; the connection node between the third resistor and the fourth resistor is connected to the switching transistor control circuit.

[0030] A battery module includes the aforementioned conversion circuit for converting a secondary battery to a dry cell battery.

[0031] This utility model provides a conversion circuit and battery module for converting a secondary battery to a dry cell battery. The conversion circuit includes a charging voltage detection circuit, a boost circuit, a secondary battery management circuit, and a buck circuit. The charging voltage detection circuit is connected to the secondary battery management circuit and is used to connect to a charging device. It outputs a first detection signal when the charging voltage output by the charging device is lower than the battery voltage of the secondary battery management circuit. The boost circuit is connected to a reference voltage receiver, the charging voltage detection circuit, and the charging device. It boosts the charging voltage based on the first detection signal and the reference voltage output by the reference voltage receiver. The circuit consists of a boost circuit and a secondary battery management circuit. The boost circuit is connected to the charging device and charges the battery according to the boost voltage or the charging voltage during charging, and outputs a first voltage during discharging. The buck circuit is connected to the secondary battery management circuit and reduces the first voltage during discharging to output a second voltage. This allows the boost circuit to increase the charging voltage when the charging voltage of the charging device is low, and then charges the secondary battery management circuit with the increased voltage. This adapts to charging devices with different charging voltages and improves the applicability of the secondary battery to dry cell conversion circuit. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of an application device for converting a secondary battery to a dry cell in the background technology of this utility model;

[0034] Figure 2 This is a circuit diagram of a secondary battery to dry cell conversion circuit in one embodiment of the present invention;

[0035] Figure 3 This is another circuit diagram of the conversion circuit from secondary battery to dry cell in one embodiment of this utility model;

[0036] Figure 4 This is another circuit diagram of the conversion circuit from secondary battery to dry cell in one embodiment of this utility model.

[0037] In the diagram: 1. Charging voltage detection circuit; 2. Boost circuit; 21. Drive circuit; 22. First voltage divider circuit; 3. Secondary battery management circuit; 31. Charging control circuit; 311. Main control circuit; 32. Secondary battery; 4. Buck circuit; 41. Switch control circuit; 42. Secondary voltage divider circuit. Detailed Implementation

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0039] It should be understood that this invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this invention to those skilled in the art. In the drawings, for clarity, the dimensions of layers and regions, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0040] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this utility model, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0041] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. When used herein, the singular forms “a,” “an,” and “ / the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “comprising,” when used in this specification, identify the presence of features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0043] To fully understand this utility model, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this utility model. Preferred embodiments of this utility model are described in detail below; however, in addition to these detailed descriptions, this utility model may have other embodiments.

[0044] This embodiment provides a conversion circuit for converting a secondary battery to a dry cell battery, such as... Figures 2 to 4 As shown, the circuit includes a charging voltage detection circuit 1, a boost circuit 2, a secondary battery management circuit 3, and a buck circuit 4. The charging voltage detection circuit 1 is connected to the secondary battery management circuit 3 and is used to connect to a charging device. It outputs a first detection signal when the charging voltage output by the charging device is less than the battery voltage of the secondary battery management circuit 3. The boost circuit 2 is connected to the charging voltage detection circuit 1 and the charging device. It boosts the charging voltage based on the reference voltage and the first detection signal and outputs a boosted voltage. The secondary battery management circuit 3 is connected to the boost circuit 2 and the charging device. It charges based on the boosted voltage or the charging voltage during charging and outputs a first voltage during discharging. The buck circuit 4 is connected to the secondary battery management circuit 3 and reduces the first voltage during discharging to output a second voltage.

[0045] The charging device is either a charger or an energy storage device. The secondary battery management circuit 3 includes a secondary battery 32. This secondary battery 32 may be a lithium-ion battery or a sodium-ion battery. A reference voltage can be obtained through a reference voltage receiver. This reference voltage receiver is used to connect to a reference voltage source to obtain the reference voltage.

[0046] As an example, the charging voltage detection circuit 1 is connected to the secondary battery management circuit 3 and is used to connect to a charging device. It detects the battery voltage of the secondary battery 32 in the secondary battery management circuit 3 and the charging voltage that the charging device can provide. When it is determined that the charging voltage output by the charging device is less than the battery voltage of the secondary battery 32, a first detection signal is output to activate the boost circuit 2. Exemplarily, the charging voltage detection circuit 1 includes a comparator. The input terminals of the comparator are connected to the secondary battery management circuit 3 and the charging device, respectively, and the output terminal of the comparator is connected to the boost circuit 2. Thus, the comparator can determine whether the charging voltage output by the charging device is less than the battery voltage of the secondary battery 32. It is understood that voltage detection and comparison techniques known to those skilled in the art can also be used to ensure that the first detection signal is output when the charging voltage output by the charging device is less than the battery voltage of the secondary battery 32. This first detection signal includes a high-level signal and a low-level signal.

[0047] As an example, the boost circuit 2 is connected to the reference voltage receiver, the charging voltage detection circuit 1, and the charging device. It is used to boost the charging voltage based on the first detection signal and the reference voltage output from the reference voltage receiver, and output a boosted voltage. In this embodiment, the boost circuit 2 boosts the charging voltage based on the reference voltage to ensure that the obtained boosted voltage meets the charging requirements of the secondary battery management circuit 3. Understandably, this reference voltage can be set according to the actual application scenario and is not limited here. Optionally, the boost circuit 2 can be a switching boost circuit 2 or a linear boost circuit 2.

[0048] As an example, the secondary battery management circuit 3 is connected to the boost circuit 2 and the charging device. It is used to charge the secondary battery 32 according to the boost voltage or the charging voltage during charging, and to output a first voltage during discharging, so that the secondary battery 32 can be used as a dry cell for energy storage and discharging. Understandably, when the charging voltage output by the charging device is less than the battery voltage of the secondary battery 32, charging and energy storage are performed through the boost voltage; when the charging voltage output by the charging device is not less than the battery voltage of the secondary battery 32, charging and energy storage are performed directly through the charging voltage.

[0049] As an example, the step-down circuit 4, connected to the secondary battery management circuit 3, is used to step down the first voltage and output a second voltage when the secondary battery management circuit 3 is discharging. In this example, the step-down circuit 4 steps down the first voltage output by the secondary battery management circuit 3 to reduce the voltage of the secondary battery 32 to the second voltage required for the dry cell to discharge.

[0050] In this embodiment, the conversion circuit for converting a secondary battery to a dry cell battery includes a charging voltage detection circuit 1, a boost circuit 2, a secondary battery management circuit 3, and a buck circuit 4. The charging voltage detection circuit 1 is connected to the secondary battery management circuit 3 and is used to connect to a charging device. When the charging voltage output by the charging device is less than the battery voltage of the secondary battery management circuit 3, it outputs a first detection signal. The boost circuit 2 is connected to a reference voltage receiver, the charging voltage detection circuit 1, and the charging device. It is used to boost the charging voltage according to the first detection signal and the reference voltage output by the reference voltage receiver and output a boosted voltage. The secondary battery management circuit 3 is connected to the boost circuit 2 and the charging device. It is used to charge the battery according to the boost voltage or the charging voltage during charging and to output the first voltage during discharging. The buck circuit 4 is connected to the secondary battery management circuit 3. It is used to step down the first voltage and output the second voltage when the secondary battery management circuit 3 is discharging. Thus, when the charging voltage of the charging device is low, the boost circuit 2 boosts the charging voltage and then charges the secondary battery management circuit 3 with the boosted voltage. This adapts to charging devices with lower charging voltage and improves the applicability of the secondary battery to dry cell conversion circuit.

[0051] In one embodiment, the boost circuit 2 includes a first inductor L1, a first PMOS transistor 1, a second NMOS transistor 1, a drive circuit 21, a first comparator CMP1, a first capacitor C1, and a first voltage divider circuit 22. The first terminal of the first inductor L1 is connected to the charging device, and the second terminal of the first inductor L1 is connected to the first terminal of the first PMOS transistor 1 and the second terminal of the second NMOS transistor 1. The second terminal of the first PMOS transistor 1 is connected to the first terminal of the first capacitor C1, and the second terminal of the first capacitor C1 is grounded. The first terminal of the second NMOS transistor 1 is grounded. The first terminal of the first voltage divider circuit 22 is connected to the second terminal of the first PMOS transistor 1 and the first terminal of the first capacitor C1. The second terminal of the voltage divider circuit 22 is grounded, and the third terminal of the first voltage divider circuit 22 is connected to the non-inverting input terminal of the first comparator CMP1. The inverting input terminal of the first comparator CMP1 is connected to the reference voltage receiving terminal and is used to feed back the boosted voltage to the first comparator CMP1. The output terminal of the first comparator CMP1 is connected to the drive circuit 21 and is used to output a first comparison signal to the drive circuit 21 according to the reference voltage and the feedback boosted voltage. The drive circuit 21 is connected to the third terminal of the first switch PMOS1, the third terminal of the second switch NMOS1, and the charging voltage detection circuit 1 and is used to control the first switch PMOS1 and the second switch NMOS1 to work according to the first detection signal and the first comparison signal.

[0052] Optionally, the first switching transistor PMOS1 and the second switching transistor NMOS1 can be either MOSFETs or bipolar transistors. Preferably, the first switching transistor PMOS1 is a PMOS transistor and the second switching transistor NMOS1 is an NMOS transistor to ensure a faster switching frequency. In this embodiment, the example of the first switching transistor PMOS1 being a PMOS transistor and the second switching transistor NMOS1 being an NMOS transistor will be used for illustration.

[0053] As an example, the second terminal of the first inductor L1 is connected to the source of the first switching transistor PMOS1 and the drain of the second switching transistor NMOS1. The drain of the first switching transistor PMOS1 is connected to the first terminal of the first capacitor C1, and the second terminal of the first capacitor C1 is grounded. The source of the second switching transistor NMOS1 is grounded. The gates of the first switching transistor PMOS1 and the second switching transistor NMOS1 are connected to the driving circuit 21.

[0054] As an example, the first voltage divider circuit 22 includes a first resistor R1 and a second resistor R2 connected in series; the connection node between the first resistor R1 and the second resistor R2 is connected to the non-inverting input of the first comparator CMP1.

[0055] As an example, when the charging voltage output by the charging device is less than the battery voltage of the secondary battery management circuit 3, the drive circuit 21 controls the first switch PMOS1 and the second switch NMOS1 to conduct alternately according to the first detection signal, so as to charge and discharge the first inductor L1, thereby making the voltage at the first terminal of the first capacitor C1 rise to the boost voltage V1, the boost voltage V1 = VIN / (1-D), where D is the conduction time t2 of the second switch NMOS1 / (the conduction time t2 of the second switch NMOS1 + the conduction time t1 of the first switch PMOS1), and VIN is the charging voltage; the boost voltage V 1. The voltage is divided by the first resistor R1 and the first resistor R1R2 in the first voltage divider circuit 22 to obtain the divided voltage V2. The divided voltage V2 is compared with the reference voltage of the first comparator CMP1, thereby controlling the drive circuit 21 to change the value of D. When the divided voltage V2 is too large, the first comparator CMP1 outputs a high level to control the drive circuit 21 to reduce the conduction time of the second switch NMOS1 to reduce the boost voltage V1. When the divided voltage V2 is too small, the first comparator CMP1 outputs a low level to control the drive circuit 21 to increase the conduction time of the second switch NMOS1 to increase the boost voltage V1.

[0056] In one embodiment, the secondary battery management circuit 3 includes a charging control circuit 31 and a secondary battery 32; the charging control circuit 31 is connected to the boost circuit 2 and the secondary battery 32, and is used to control the charging current of the secondary battery 32 according to the battery voltage of the secondary battery 32; the secondary battery 32 is connected to the charging voltage detection circuit 1 and the buck circuit 4, and is used to charge according to the charging current during charging and output a first voltage during discharging.

[0057] In this embodiment, the charging control circuit 31 is connected to the boost circuit 2 and the secondary battery 32, and is used to control the charging current of the secondary battery 32 according to the battery voltage of the secondary battery 32; the secondary battery 32 is connected to the charging voltage detection circuit 1 and the buck circuit 4, and is used to charge according to the charging current during charging and output the first voltage during discharging to prevent the charging current from being too large and improve safety.

[0058] In one embodiment, the charging control circuit 31 includes a fifth switching transistor PMOS2 and a main control circuit 311; the first terminal of the fifth switching transistor PMOS2 is connected to the boost circuit 2, and the second terminal of the fifth switching transistor PMOS2 is connected to the secondary battery management circuit 3; the main control circuit 311 is connected to the secondary battery management circuit 3 and the third terminal of the fifth switching transistor PMOS2, and is used to control the operation of the fifth switching transistor PMOS2 according to the battery voltage of the secondary battery management circuit 3.

[0059] Among them, the fifth switch PMOS2 is a MOS transistor, specifically a PMOS transistor.

[0060] As an example, the source of the fifth switching transistor PMOS2 is connected to the boost circuit 2, the drain of the fifth switching transistor PMOS2 is connected to the secondary battery management circuit 3, and the gate of the fifth switching transistor PMOS2 is connected to the main control circuit 311.

[0061] In this embodiment, the main control circuit 311 adjusts the gate voltage of the fifth switching transistor PMOS2 according to the battery voltage, thereby controlling the voltage between the gate and source of the fifth switching transistor PMOS2, and thus achieving precise control of the drain current, i.e., the charging current.

[0062] In one embodiment, the step-down circuit 4 includes a second inductor L2, a third switch PMOS3, a fourth switch NMOS2, a switch control circuit 41, a second capacitor C2, and a second voltage divider circuit 42. The first terminal of the third switch PMOS3 is connected to the secondary battery management circuit 3, and the second terminal of the third switch PMOS3 is connected to the second terminal of the fourth switch NMOS2. The first terminal of the fourth switch NMOS2 is grounded. The first terminal of the second inductor L2 is connected to the second terminals of both the third switch PMOS3 and the fourth switch NMOS2. The second terminal of the second inductor L2 is connected to the second terminal of the second switch PMOS3 and the second terminal of the fourth switch NMOS2. The first terminals of the two capacitors C2 are connected together, and the second terminal of the second capacitor C2 is grounded. The first terminal of the second voltage divider circuit 42 is connected to the second terminal of the second inductor L2 and the first terminal of the second capacitor C2. The second terminal of the second voltage divider circuit 42 is grounded. The third terminal of the second voltage divider circuit 42 is connected to the switching transistor control circuit 41, which is used to feed back the second voltage to the switching transistor control circuit 41. The switching transistor control circuit 41 is connected to the third terminal of the third switching transistor PMOS3 and the third terminal of the fourth switching transistor NMOS2, which is used to control the third switching transistor PMOS3 and the fourth switching transistor NMOS2 to work according to the feedback second voltage.

[0063] Optionally, the third switch PMOS3 and the fourth switch NMOS2 can be MOSFETs or transistors. Preferably, the third switch PMOS3 is a PMOS transistor and the fourth switch NMOS2 is an NMOS transistor to ensure a faster switching frequency. In this embodiment, the example of the third switch PMOS3 being a PMOS transistor and the fourth switch NMOS2 being an NMOS transistor will be used for illustration.

[0064] As an example, the second voltage divider circuit 42 includes a third resistor R3 and a fourth resistor R4 connected in series; the connection node between the third resistor R3 and the fourth resistor R4 is connected to the switching transistor control circuit 41.

[0065] As an example, the switching control circuit 41 controls the third switch PMOS3 and the fourth switch NMOS2 to conduct respectively, so as to charge and discharge the second inductor L2, thereby forming the voltage reduction function of the secondary battery management circuit 3. The second voltage is divided by the third resistor R3 and the fourth resistor R4 and then inputs a divided voltage V3 = VOUT * R4 / (R3 + R4) to the switching control circuit 41, where VOUT is the second voltage, R3 is the resistance value of the third resistor R3, and R4 is the resistance value of the fourth resistor R4. When the divided voltage V3 is too large, the switching control circuit 41 turns off the third switch PMOS3 and turns on the fourth switch NMOS2, and the second capacitor C2 discharges, reducing the second voltage VOUT. When the divided voltage V3 is small, the switching control circuit 41 turns off the third switch PMOS3 and turns on the fourth switch NMOS2, charging the second capacitor C2 and increasing the second voltage VOUT. Through the above process, the voltage reduction function of the second capacitor C2VOUT being lower than the voltage VBAT of the secondary battery 32 is achieved.

[0066] As an example, the switching transistor control circuit 41 may also include a drive circuit 21 and a first comparator CMP1. The first input terminal of the first comparator CMP1 is connected to the second voltage divider circuit 42, the second input terminal is used to receive the reference voltage compared with the divided voltage V3, and the output terminal is connected to the drive circuit 21. The drive circuit 21 is connected to the third terminal of the third switch PMOS3 and the third terminal of the fourth switch NMOS2. According to the comparison signal output by the first comparator CMP1, the third switch PMOS3 and the fourth switch NMOS2 are controlled to be turned on respectively.

[0067] This embodiment provides a battery module, including the aforementioned conversion circuit for converting secondary batteries to dry batteries.

[0068] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A conversion circuit for converting a secondary battery into a dry battery, characterized by comprising: It includes a charging voltage detection circuit, a boost circuit, a secondary battery management circuit, and a buck circuit; The charging voltage detection circuit is connected to the secondary battery management circuit and is used to connect to the charging device. When the charging voltage output by the charging device is less than the battery voltage of the secondary battery management circuit, the circuit outputs a first detection signal. The boost circuit is connected to the charging voltage detection circuit and the charging device, and is used to boost the charging voltage according to the reference voltage and the first detection signal, and output the boost voltage. The secondary battery management circuit is connected to the boost circuit and the charging device, and is used to charge according to the boost voltage or the charging voltage during charging, and to output a first voltage during discharging; The step-down circuit is connected to the secondary battery management circuit and is used to step down the first voltage and output a second voltage when the secondary battery management circuit is discharging.

2. The conversion circuit from a secondary battery to a dry cell according to claim 1, characterized by The boost circuit includes a first inductor, a first switching transistor, a second switching transistor, a driver circuit, a first comparator, a first capacitor, and a first voltage divider circuit. The first terminal of the first inductor is connected to the charging device, the second terminal of the first inductor is connected to the first terminal of the first switching transistor and the second terminal of the second switching transistor, the second terminal of the first switching transistor is connected to the first terminal of the first capacitor, the second terminal of the first capacitor is grounded, and the first terminal of the second switching transistor is grounded. The first terminal of the first voltage divider circuit is connected to the second terminal of the first switching transistor and the first terminal of the first capacitor. The second terminal of the first voltage divider circuit is grounded. The third terminal of the first voltage divider circuit is connected to the non-inverting input terminal of the first comparator. The inverting input terminal of the first comparator is connected to the reference voltage receiving terminal, which is used to feed back the boosted voltage to the first comparator. The output of the first comparator is connected to the driving circuit and is used to output a first comparison signal to the driving circuit based on the reference voltage and the feedback boost voltage. The driving circuit is connected to the third terminal of the first switching transistor, the third terminal of the second switching transistor, and the charging voltage detection circuit, and is used to control the first switching transistor and the second switching transistor to work according to the first detection signal and the first comparison signal.

3. The conversion circuit from a secondary battery to a dry cell according to claim 2, characterized by The first switching transistor is a PMOS transistor; the second switching transistor is an NMOS transistor.

4. The conversion circuit from a secondary battery to a dry cell according to claim 2, wherein The first voltage divider circuit includes a first resistor and a second resistor connected in series; the connection node between the first resistor and the second resistor is connected to the non-inverting input terminal of the first comparator.

5. The conversion circuit from a secondary battery to a dry cell according to claim 1, characterized by The secondary battery management circuit includes a charging control circuit and a secondary battery; The charging control circuit is connected to the boost circuit, the charging device and the secondary battery, and is used to control the charging current of the secondary battery according to the battery voltage of the secondary battery. The secondary battery is connected to the charging voltage detection circuit and the step-down circuit, and is used to charge according to the charging current during charging and to output the first voltage during discharging.

6. The conversion circuit from a secondary cell to a dry cell according to claim 5, wherein The charging control circuit includes a fifth switching transistor and a main control circuit. The first terminal of the fifth switching transistor is connected to the boost circuit, and the second terminal of the fifth switching transistor is connected to the secondary battery management circuit. The main control circuit is connected to the secondary battery management circuit and the third terminal of the fifth switching transistor, and is used to control the operation of the fifth switching transistor according to the battery voltage of the secondary battery management circuit.

7. The conversion circuit from a secondary battery to a dry cell according to claim 1, wherein The step-down circuit includes a second inductor, a third switching transistor, a fourth switching transistor, a switching transistor control circuit, a second capacitor, and a second voltage divider circuit. The first terminal of the third switch is connected to the secondary battery management circuit, the second terminal of the third switch is connected to the second terminal of the fourth switch, and the first terminal of the fourth switch is grounded. The first end of the second inductor is connected to the second end of the third switch and the second end of the fourth switch, the second end of the second inductor is connected to the first end of the second capacitor, and the second end of the second capacitor is grounded. The first terminal of the second voltage divider circuit is connected to the second terminal of the second inductor and the first terminal of the second capacitor. The second terminal of the second voltage divider circuit is grounded. The third terminal of the second voltage divider circuit is connected to the switching transistor control circuit and is used to feed back the second voltage to the switching transistor control circuit. The switching control circuit is connected to the third terminal of the third switching transistor and the third terminal of the fourth switching transistor, and is used to control the operation of the third switching transistor and the fourth switching transistor according to the feedback of the second voltage.

8. The conversion circuit from a secondary battery to a dry cell according to claim 7, wherein The third switch is a PMOS transistor; the fourth switch is an NMOS transistor.

9. The conversion circuit from a secondary battery to a dry cell according to claim 7, wherein The second voltage divider circuit includes a third resistor and a fourth resistor connected in series; the connection node between the third resistor and the fourth resistor is connected to the switching transistor control circuit.

10. A battery module, characterized by It includes a conversion circuit for converting a secondary battery to a dry cell as described in any one of claims 1 to 9.

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