Protection circuit for rechargeable battery

Abstract

The embodiment of the utility model discloses a protection circuit for a rechargeable battery, which relates to the technical field of storage battery charging and discharging and comprises a first control chip, a second control chip, a charging module, a discharging module, a first overload protection device and a second overload protection device. The discharging module is respectively connected with the first overload protection device, the first control chip and a preset rechargeable battery; the charging module is respectively connected with the first control chip, the second control chip, the second overload protection device and the rechargeable battery; a preset charger is respectively connected with the first control chip and the second overload protection device, and the first overload protection device is connected with a preset discharge electrode. Multiple protection is set for battery charging and discharging, and the effect of improving the safety performance of the battery pack is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery charging and discharging, in particular to a protection circuit for a rechargeable battery. Background Art

[0002] Rechargeable batteries are economical, environmentally friendly, have sufficient power, are suitable for high power, and can be used for a long time, and are deeply loved by consumers. Due to structural negligence, such consumer electronic products, on the one hand, have serious consequences when the battery is connected in reverse, and the negative pressure formed by the reverse connection can easily break through the power chip and cause an explosion; on the other hand, overcharging and over-discharging of the battery will cause irreversible damage to the battery itself, seriously affecting the battery's service life. Utility Model Content

[0003] The technical problem to be solved by the embodiments of the utility model is that there are potential safety hazards in the structure of the rechargeable battery, and it is necessary to improve the safety performance to ensure the safety of users.

[0004] In order to solve the above problems, the embodiment of the utility model discloses a protection circuit for a rechargeable battery. Multiple protections are set up for battery charging and discharging to achieve the effect of improving the safety performance of the battery pack.

[0005] The utility model provides a protection circuit for a rechargeable battery, which includes a first control chip, a second control chip, a charging module, a discharging module, a first overload protection device and a second overload protection device; the discharging module is respectively connected to the first overload protection device, the first control chip and a preset rechargeable battery; the charging module is respectively connected to the first control chip, the second control chip, the second overload protection device and the rechargeable battery; the preset charger is respectively connected to the first control chip and the second overload protection device, and the first overload protection device is connected to a preset discharge electrode.

[0006] A further technical solution is that the charging module includes a first MOS tube and a second MOS tube, the first MOS tube is respectively connected to the first control chip, the second MOS tube and the rechargeable battery, and the second MOS tube is respectively connected to the second control chip and the second overload protection device.

[0007] A further technical solution is that the first MOS tube includes a first source, a first gate and a first drain, the first source is connected to the second MOS tube, the first gate is connected to the first control chip, and the first drain is connected to the rechargeable battery.

[0008] A further technical solution is that the second MOS tube includes a second source, a second gate and a second drain, the second source is connected to the second overload protection device, the second gate is connected to the second control chip, and the second drain is connected to the first MOS tube.

[0009] A further technical solution is that it also includes an identification module, which is connected to the first control chip and the charger respectively.

[0010] A further technical solution is that the identification module includes a switch and an anti-reverse connection unit, the switch is connected to the anti-reverse connection unit and the first control chip respectively, and the anti-reverse connection unit is connected to the charger.

[0011] A further technical solution is that the discharge module includes a plurality of third MOS tubes connected in parallel.

[0012] A further technical solution is that it also includes a third control chip, and the third control chip is connected to the first control chip.

[0013] A further technical solution is that the first overload protection device is a fuse.

[0014] A further technical solution is that the second overload protection device is a fuse.

[0015] Compared with the prior art, the technical effects that can be achieved by the embodiments of the present invention include:

[0016] The battery charging has four-fold protection: 1. The first control chip directly controls the connection / disconnection of the charging module; 2. The second control chip detects the voltage of the charging module. When the voltage of the charging module exceeds the threshold, the charging module is disconnected and charging is stopped; 3. The charger stops battery charging according to the low level feedback from the circuit; 4. The second overload protection device prevents the circuit from overloading.

[0017] The battery discharge has dual protection: first, the first control chip directly controls the connection / disconnection of the discharge module; second, the first overload protection device prevents the circuit from overloading. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of a protection circuit structure for a rechargeable battery provided in an embodiment of the utility model;

[0020] Figure 2 A schematic diagram of another protection circuit structure for a rechargeable battery provided in an embodiment of the utility model;

[0021] Figure 3 A circuit diagram of a second control chip U8 provided in an embodiment of the utility model;

[0022] Figure 4 A circuit diagram of a third control chip U5 provided in an embodiment of the utility model.

[0023] Reference numerals

[0024] The first control chip U7, the second control chip U8, the identification module 1, the charging module 3, the discharging module 4, the first overload protection device 5, the second overload protection device 6, the first MOS tube Q40, the second MOS tube Q41, the third control chip U5, the rechargeable battery 91, and the charger 92. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments. Similar component numbers in the drawings represent similar components. Obviously, the embodiments to be described below are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described 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 combinations thereof.

[0027] It should also be understood that the terms used in this utility model embodiment specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model embodiments. As used in the utility model embodiment specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] See also Figure 1-4, an embodiment of the utility model provides a protection circuit for a rechargeable battery 91. The protection circuit for the rechargeable battery 91 includes a first control chip U7, a second control chip U8, a charging module 3, a discharging module 4, a first overload protection device 5 and a second overload protection device 6; the discharging module 4 is respectively connected to the first overload protection device 5, the first control chip U7 and a preset rechargeable battery 91; the charging module 3 is respectively connected to the first control chip U7, the second control chip U8, the second overload protection device 6 and the rechargeable battery 91; the preset charger 92 is respectively connected to the first control chip U7 and the second overload protection device 6, and the first overload protection device 5 is connected to a preset discharge electrode. The specific introduction of each component is as follows:

[0029] In this embodiment, the charging module 3 is connected to the negative pole (B-) of the rechargeable battery 91 and is connected to the negative pole (P-) of the charger 92, and the positive pole of the rechargeable battery 91 is connected to the charger 92. The first control chip U7 and the second control chip U8 are connected to the charging module 3 respectively. When the first control chip U7 outputs a high voltage, the charging module 3 operates, and the charger 92 is connected to the rechargeable battery 91 through the charging module 3 to realize charging of the rechargeable battery 91. When the first control chip U7 outputs a low voltage, the charging module 3 stops operating to realize stopping charging of the rechargeable battery 91. The second control chip U8 is used to detect the voltage of the charging module 3. If the voltage value reaches the preset voltage value threshold, the second control chip U8 outputs a low level to control the charging module 3 to turn off, stop the charging module 3 from operating, and avoid overcharging. When the battery is not fully charged, the first control chip U7 outputs a high level to the charger 92 through the identification module 1. The high level of the identification module 1 received by the charger 92 is a valid signal. If the charger 92 receives a low level from the identification module 1, it stops charging the battery. The second overload protection device 6 is connected in series between the charging module 3 and the charger 92 . When the charging current is greater than the preset current threshold of the second overload protection device 6 , the second overload protection device 6 is disconnected to cut off the charging, thereby realizing charging protection of the rechargeable battery 91 .

[0030] When the discharge voltage reaches the over-discharge voltage threshold of the first control chip U7, the first control chip U7 turns off the discharge module 4 to terminate the discharge. The first overload protection device 5 is connected in series between the discharge module 4 and the charger 92. When the discharge current is greater than the preset current threshold of the first overload protection device 5, the first overload protection device 5 is disconnected to achieve discharge cutoff, thereby achieving discharge protection of the rechargeable battery 91.

[0031] The preset discharge electrode includes the discharge seat of the battery, also referred to as the negative electrode (P-) of the battery, which is used to supply power to external devices.

[0032] The working process of the protection circuit for the rechargeable battery 91 is as follows:

[0033] First level of protection: When the battery is not fully charged, the first control chip U7 outputs a high voltage of 11V, turns on the charging MOS tube Q40 and MOS tube Q41, and charges. When the battery voltage is fully charged, the first control chip U7 outputs a low voltage of 0V, turns off the charging MOS tube Q40 and MOS tube Q41, and stops charging.

[0034] Second level protection: When charging is in progress, the first control chip U7 fails, and the voltage of a certain battery cell reaches the overcharge protection voltage V1 (4.225V) of the first control chip U7, and the charging MOS tube Q40 and MOS tube Q41 cannot be turned off, resulting in continued charging. When the voltage of a certain battery cell reaches the overcharge protection voltage value V2 (4.25V) of the second control chip U8, the second control chip U8 control pin 14 (CO) outputs a low level to control Q29, turning off the MOS tube Q41.

[0035] The third level of protection: The first control chip U7 outputs a high level of 3.3V to the charger 92 through the identification module 1 when the battery is not fully charged. When the charger 92 receives the high level from the identification module 1, it is effective to charge the battery normally. When the first control chip U7 fails, it cannot output a high level through the identification module 1, and the charger 92 stops charging the battery.

[0036] The fourth level of protection: a second overload protection device 6 is connected in series to the charging output terminal. When the charging current is greater than 3A, after charging for a period of time, the second overload protection device 6 disconnects the circuit and charging is terminated.

[0037] Continue to see Figure 1-4 In this embodiment, the charging module 3 includes a first MOS tube Q40 and a second MOS tube Q41. The first MOS tube Q40 is connected to the first control chip U7, the second MOS tube Q41 and the charging battery 91 respectively. The second MOS tube Q41 is connected to the second control chip U8 and the second overload protection device 6 respectively.

[0038] Furthermore, the first MOS transistor Q40 includes a first source, a first gate and a first drain. The first source is connected to the second MOS transistor Q41 , the first gate is connected to the first control chip U7 , and the first drain is connected to the rechargeable battery 91 .

[0039] Furthermore, the second MOS transistor Q41 includes a second source, a second gate and a second drain, the second source is connected to the second overload protection device 6, the second gate is connected to the second control chip U8, and the second drain is connected to the first MOS transistor Q40.

[0040] In one embodiment, the first MOS transistor Q40 includes a first source, a first gate and a first drain, and the first MOS transistor Q40 is an NMOS; the second MOS transistor Q41 includes a second source, a second gate and a second drain, and the second MOS transistor Q41 is an NMOS.

[0041] Furthermore, it also includes an identification module 1, which is connected to the first control chip U7 and the charger 92 respectively.

[0042] Specifically, the identification module 1 is used to identify the charger 92. When the battery is not fully charged, the identification module 1 outputs a high level of 3.3V to the charger 92. When the charger 92 receives the high level from the identification module 1, it is effective to charge the battery normally. When the first control chip U7 fails, it cannot output a high level through the identification module 1, and the charger 92 stops charging the battery. The identification module 1 is used to prevent the charger 92 from overcharging the battery due to the failure of the first control chip U7.

[0043] Furthermore, the identification module 1 includes a switch and an anti-reverse connection unit, the switch is connected to the anti-reverse connection unit and the first control chip U7 respectively, and the anti-reverse connection unit is connected to the charger 92 .

[0044] Specifically, the switch includes a transistor Q43 and a transistor Q44. In one embodiment, a resistor is connected between the transistor Q43 and the transistor Q44. The reverse connection protection unit includes a diode D28. A resistor is connected between the transistor Q44 and the diode D28 to prevent excessive current in the circuit.

[0045] Furthermore, the discharge module 4 includes a plurality of third MOS tubes connected in parallel.

[0046] Specifically, the third MOS tube includes MOS tube Q1, MOS tube Q38, MOS tube Q39, and MOS tube Q42. A plurality of third MOS tubes are connected in parallel to form a MOS tube group, and active current balancing is performed to reduce the difference in Vgs discreteness to 1 / Kv times. After current balancing, not only the current and power consumption (temperature) are balanced, but also the input and output can be linearized.

[0047] Furthermore, it also includes a third control chip U5, and the third control chip U5 is connected to the first control chip U7.

[0048] Specifically, the third control chip U5 includes a storage control chip connected to the first control chip U7 and used to store the determination logic of the first control chip U7.

[0049] Furthermore, the first overload protection device 5 is a fuse.

[0050] Specifically, the first overload protection device 5 is usually a fuse with a current threshold of 25A. When the discharge current is greater than 25A or short-circuited, the first overload protection device 5 disconnects the circuit and the discharge is terminated, thereby realizing discharge protection of the rechargeable battery 91.

[0051] Furthermore, the second overload protection device 6 is a fuse.

[0052] Specifically, the second overload protection device 6 is usually a fuse with a current threshold of 3A. When the charging current is greater than 3A, after charging for a period of time, the temperature-controlled fuse is disconnected and charging is terminated, thereby realizing charging protection of the rechargeable battery 91 .

[0053] 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.

[0054] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms should not be understood as necessarily being directed to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0059] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include these modifications and variations.

[0060] The above is a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the utility model, and these modifications or replacements should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A protection circuit for a rechargeable battery, characterized in that: It includes a first control chip, a second control chip, a charging module, a discharging module, a first overload protection device and a second overload protection device; The discharge module is respectively connected to the first overload protection device, the first control chip and a preset rechargeable battery; The charging module is respectively connected to the first control chip, the second control chip, the second overload protection device and the rechargeable battery; The preset charger is connected to the first control chip and the second overload protection device respectively, and the first overload protection device is connected to the preset discharge electrode.

2. The protection circuit for a rechargeable battery according to claim 1, characterized in that: The charging module includes a first MOS tube and a second MOS tube, the first MOS tube is respectively connected to the first control chip, the second MOS tube and the charging battery, and the second MOS tube is respectively connected to the second control chip and the second overload protection device.

3. The protection circuit for a rechargeable battery according to claim 2, characterized in that: The first MOS transistor includes a first source, a first gate and a first drain, the first source is connected to the second MOS transistor, the first gate is connected to the first control chip, and the first drain is connected to the rechargeable battery.

4. The protection circuit for a rechargeable battery according to claim 2, characterized in that: The second MOS tube includes a second source, a second gate and a second drain, the second source is connected to the second overload protection device, the second gate is connected to the second control chip, and the second drain is connected to the first MOS tube.

5. The protection circuit for a rechargeable battery according to claim 1, characterized in that: It also includes an identification module, which is connected to the first control chip and the charger respectively.

6. The protection circuit for a rechargeable battery according to claim 5, characterized in that: The identification module includes a switch and an anti-reverse connection unit, the switch is connected to the anti-reverse connection unit and the first control chip respectively, and the anti-reverse connection unit is connected to the charger. 7 . The protection circuit for a rechargeable battery according to claim 1 , wherein the discharge module comprises a plurality of third MOS tubes connected in parallel.

8. The protection circuit for a rechargeable battery according to claim 1, characterized in that: It also includes a third control chip, which is connected to the first control chip.

9. The protection circuit for a rechargeable battery according to claim 1, characterized in that: The first overload protection device is a fuse.

10. The protection circuit for a rechargeable battery according to claim 1, characterized in that: The second overload protection device is a fuse.

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