An electronic device

Abstract

An electronic device can include a battery system that can be used to power the electronic device, the battery system including a battery management circuit and a battery cell, the battery management circuit can be integrated on a mainboard of the electronic device, the battery cell can be buckled with the mainboard through a connector, and the battery cell is electrically connected with the battery management circuit through the connector. In the battery system, a secondary recoverable protection device is arranged at the positive and negative terminals of the battery management circuit, so that when the battery management circuit is placed on a mainboard with a small interlayer thickness, various short circuit problems including interlayer short circuit of the mainboard can be avoided. Moreover, the layout and placement position of the battery cell and the mainboard can be diversified, and can be widely applied to new product architecture forms.

Description

Technical Field

[0001] This application relates to the field of terminal technology, and more particularly to an electronic device. Background Technology

[0002] Currently, the design of laptops, tablets, and other terminal products is trending towards thinner, lighter, and fanless designs, while the demands for performance and heat dissipation are also increasing. To achieve long battery life, unused space within the device is typically reserved for the battery compartment to increase battery capacity. Traditional multi-cell batteries, however, involve soldering the battery management system circuit board and multiple battery cells together and securing them with frames, tape, and other means to form a battery pack. This integrated battery pack usually occupies a significant amount of internal space and can interfere with circuit boards or structural components, reducing the flexibility of the overall architecture and hindering the evolution towards miniaturization and thinner designs. Furthermore, depending on the product's battery life and cost requirements, there is also a need to allow for a variable number of battery cells connected in series.

[0003] Therefore, it is worth considering how to separate the cells and battery management system of the integrated battery pack so that the number of cells can be flexibly adjusted and the components can be distributed in the spare space of the whole machine as needed. Summary of the Invention

[0004] In a first aspect, embodiments of this application provide an electronic device, comprising: a motherboard, a battery management circuit, a battery cell, a first charging / discharging port, and a second charging / discharging port; the battery management circuit includes a first control unit, a second control unit, a first switching unit, and a second switching unit; the battery management circuit is located on the motherboard, the battery cell is fastened to the motherboard via a connector, and the battery cell is electrically connected to the battery management circuit via the connector; the first charging / discharging port is electrically connected to the positive terminal of the battery cell, and the second charging / discharging port is electrically connected to the negative terminal of the battery cell; the first switching unit is connected in series between the first charging / discharging port and the positive terminal of the battery cell, and the second switching unit is connected in series between the second charging / discharging port and the negative terminal of the battery cell; the first control unit is electrically connected to the first switching unit and is used to control the first switching unit to be turned on or off, and the second control unit is electrically connected to the second switching unit and is used to control the second switching unit to be turned on or off.

[0005] This electronic device separates the battery management circuitry from the battery cells, integrating the battery management circuitry onto the motherboard. The battery cells are then attached to the motherboard via connectors. The battery cells and battery management circuitry no longer need to be packaged together, and the position of the battery cells can be freely adjusted according to the internal space of the electronic device. This improves the internal space utilization of the electronic device and solves the internal architecture problems caused by battery packaging.

[0006] Due to the small spacing between circuit boards inside electronic devices, various short-circuit phenomena are prone to occur when using the battery structure provided in this application. Existing battery management circuits include two protection circuits, both connected to the positive terminal of the battery cell. In the event of a short circuit between the positive terminal of the battery cell and the first charge / discharge port, the protection circuit can be used to disconnect the short-circuit loop. However, existing battery management systems only protect a portion of the circuit. Therefore, in this application, for the two protection circuits in the battery management circuit, the electronic device can connect one protection circuit to the positive terminal of the battery cell and the other to the negative terminal. This allows the electronic device to disconnect the short-circuit loop in the event of a short circuit between the positive terminal of the battery cell and the second charge / discharge port, or between the negative terminal of the battery cell and the first charge / discharge port, effectively improving battery safety.

[0007] In conjunction with the first aspect, the first control unit includes a first charging control pin, a first discharging control pin, a first voltage detection pin, a first grounding pin, and a first current detection pin; the first switching unit includes a first charging switch and a first discharging switch; the first charging control pin is electrically connected to the control terminal of the first charging switch, and the first discharging control pin is electrically connected to the control terminal of the first discharging switch; the first voltage detection pin is electrically connected to the battery cell unit, and the first voltage detection pin is used to detect the voltage of the battery cell unit; the first current detection pin is used to detect the charging and discharging current of the battery cell unit; and the first grounding pin is used to connect to a first ground.

[0008] The first control unit can detect the voltage and current of the battery cell. When abnormal voltage or current is detected, the first control unit can control the first charging switch or the first discharging switch to disconnect, thereby protecting the battery cell and other components of the electronic device. When the voltage and current of the battery cell return to normal, or after user intervention, the first control unit can also control the first charging switch or the first discharging switch to turn on, allowing the electronic device to return to normal operation without being damaged or unable to recover due to the aforementioned protection actions.

[0009] When a short circuit occurs between the negative terminal of the battery cell and the first charging / discharging port, the first control unit can also control the first charging switch or the first discharging switch to disconnect, thereby achieving short circuit protection.

[0010] In conjunction with the first aspect, the second control unit includes a second charging control pin, a second discharging control pin, a second voltage detection pin, and a second current detection pin; the second switching unit includes a second charging switch and a second discharging switch; the second charging control pin is electrically connected to the control terminal of the second charging switch, and the second discharging control pin is electrically connected to the control terminal of the second discharging switch; the second voltage detection pin is electrically connected to the battery cell and is used to detect the voltage of the battery cell; the second current detection pin is used to detect the charging and discharging current of the battery cell; a second ground is connected between the second switching unit and the second charging and discharging port.

[0011] The second control unit can detect the voltage and current of the battery cell. When abnormal voltage or current is detected, the second control unit can control the second charging switch or the second discharging switch to disconnect, thereby protecting the battery cell and other components of the electronic device. When the voltage and current of the battery cell return to normal, or after user intervention, the second control unit can also control the second charging switch or the second discharging switch to turn on, allowing the electronic device to return to normal operation without being damaged or unable to recover due to the aforementioned protection actions.

[0012] When a short circuit occurs between the positive terminal of the battery cell and the second charging / discharging port, the second control unit can also control the second charging switch or the second discharging switch to disconnect, thereby achieving short circuit protection.

[0013] In conjunction with the first aspect, the second switching unit is connected to the second ground by the first ground.

[0014] Because there is a second ground between the second switching unit and the second charging / discharging port, and a first ground between the second switching unit and the second ground, the second switching unit is located on a line outside the first ground to the second ground, and the first ground and the second ground are no longer separated by the second switching unit.

[0015] When an electronic device is operating, its motherboard needs to communicate with the first control unit to obtain the battery cell's operating status, enabling management of the device's charging and discharging, and providing users with information about the device's battery level. If the first reference ground of the first control unit and the second reference ground of the motherboard are isolated by a second switching unit, in some scenarios, the disconnection of the second switching unit will cause a difference in potential between the first and second grounds. This will lead to communication signal disruption between the motherboard and the first control unit, preventing them from communicating.

[0016] Adjusting the positions of the first ground and the second switching unit ensures that the first ground connected to the first control unit and the second ground on the motherboard side are not disconnected by the second switching unit. This allows the potentials of the first ground and the second ground to remain almost the same, enabling the battery management circuit to maintain communication with the motherboard at all times.

[0017] In conjunction with the first aspect, the second voltage detection pin of the second control unit is also used to connect to the system voltage.

[0018] The electronic device can power the first control unit via a battery cell, and power the second control unit via the battery cell and the system voltage. The second control unit can receive the higher of the battery cell voltage and the system voltage as its supply voltage. This allows both the first and second control units to operate normally while also shielding the undervoltage protection function of the second control unit, preventing the electronic device from being affected by its undervoltage protection threshold and broadening the selection range for the second control unit.

[0019] In conjunction with the first aspect, the first parameter threshold and the second parameter threshold are different; the first parameter threshold is the threshold that triggers the first control unit to control the state change of the first switch unit, and the second parameter threshold is the threshold that triggers the second control unit to control the state change of the second switch unit.

[0020] The first control unit and the second control unit have different voltage and current thresholds for triggering protection. When the protection is triggered, the first control unit and the second control unit act in sequence, which can realize two-level protection of the circuit and enhance the protection effect of the circuit.

[0021] For example, the first parameter threshold may include: a first discharge overcurrent threshold, a first charging overcurrent threshold, a first overvoltage threshold, and a first undervoltage threshold. The second parameter threshold may include: a second discharge overcurrent threshold, a second charging overcurrent threshold, a second overvoltage threshold, and a second undervoltage threshold. When the first control unit is responsible for primary protection, i.e., the first control unit triggers protection first, and the second control unit performs secondary protection, the first discharge overcurrent threshold is less than the second discharge overcurrent threshold, the first charging overcurrent threshold is less than the second charging overcurrent threshold, the first overvoltage threshold is less than the second overvoltage threshold, and the first undervoltage threshold is greater than the second undervoltage threshold.

[0022] In conjunction with the first aspect, the battery management circuit also includes a first circuit comprising one or more diodes connected in series, the first circuit being located between the positive terminal of the cell and the second voltage detection pin.

[0023] Connecting one or more diodes in series between the positive terminal of the battery cell and the second voltage detection pin allows the actual voltage detected by the second voltage detection pin to be the positive terminal voltage of the battery cell minus the sum of the forward voltages of the one or more series diodes. This ensures that when the second control unit detects that the voltage has reached a second overvoltage threshold, the actual operating voltage of the battery cell is the second overvoltage threshold plus the sum of the forward voltages of the one or more series diodes. In other words, the battery cell can operate at a voltage higher than the second overvoltage threshold, effectively increasing the overvoltage protection threshold of the second control unit.

[0024] This allows the actual overvoltage protection threshold of the second control unit to be adjusted via hardware. Even if the overvoltage protection threshold of one model of the second control unit does not meet the requirements, the actual overvoltage protection threshold can be adjusted to satisfy the needs. This broadens the selection range for the second control unit.

[0025] In conjunction with the first aspect, the battery management circuit also includes a current sensing resistor and a voltage divider network, the voltage divider network including multiple series resistors; the current sensing resistor is connected in series between the cell unit and the second switching unit, and the voltage divider network is connected in parallel with the current sensing resistor.

[0026] The second control unit determines the current flowing through the current-sensing resistor based on the resistance value by detecting the voltage across the resistor. In this application, a voltage divider network can be connected in parallel across the current-sensing resistor, and this network can include multiple resistors connected in series. The current-sensing pin of the second control unit can be connected to one of the resistors in the voltage divider network. Based on the series voltage divider principle, the voltage detected by the second control unit is less than the actual voltage across the current-sensing resistor. Therefore, based on Ohm's law, the current detected by the second control unit is less than the actual current flowing through the current-sensing resistor. Thus, when the second control unit detects that the current has reached the overcurrent protection threshold, the actual current in the circuit has already exceeded that threshold. This effectively increases the overcurrent protection threshold of the second control unit.

[0027] This allows the actual overcurrent protection threshold of the second control unit to be adjusted via hardware. Even if the overcurrent protection threshold of one model of the second control unit does not meet the requirements, the actual overcurrent protection threshold can be adjusted to satisfy the needs. This broadens the selection range for the second control unit.

[0028] The battery cell unit may include multiple cells connected in series, including at least a head cell and a tail cell. The first charge / discharge port is connected to the positive terminal of the head cell, and the second charge / discharge port is electrically connected to the negative terminal of the tail cell.

[0029] In this way, the number of battery cells in electronic devices can be adjusted, allowing the electronic devices to adjust the number of battery cells according to different battery life requirements.

[0030] In addition to its detection function, the second control unit also has a second voltage detection pin that can be connected to the positive terminal of a battery cell, and a second current detection pin that can be connected to the negative terminal of a battery cell, thereby enabling the battery cell to supply power to the second control unit.

[0031] If the battery cell unit includes multiple cells connected in series, the second control unit can be powered by these cells. The second voltage detection pin is connected to the positive terminal of the head cell, and the second current detection pin is electrically connected to the negative terminal of the tail cell. This increases the supply voltage of the second control unit, and consequently, the output voltage of the second control unit is also increased. This allows the second charging control pin and the second discharging control pin of the second control unit to output higher control voltages, which can drive switching units with higher trigger thresholds. This expands the selection range of the second switching units and facilitates the architecture design of electronic devices. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the internal structure of a battery pack provided in an embodiment of this application;

[0033] Figure 2 This is a schematic structural diagram of a battery pack provided in an embodiment of this application;

[0034] Figure 3 This is a circuit diagram of a battery pack provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of the structure of a battery system provided in an embodiment of this application;

[0036] Figure 5 This is a schematic circuit diagram of a battery system provided in an embodiment of this application;

[0037] Figure 6A This is a partial circuit enlarged view of U3 provided in the embodiments of this application;

[0038] Figure 6B This is another enlarged partial circuit diagram of U3 provided in the embodiments of this application;

[0039] Figure 7 This is a circuit diagram of the battery system provided in an embodiment of this application;

[0040] Figure 8 This is a circuit diagram of another battery system provided in an embodiment of this application;

[0041] Figure 9 This is a circuit diagram of another battery system provided in an embodiment of this application;

[0042] Figure 10 This is a circuit diagram of another battery system provided in an embodiment of this application. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. The terms “first” and “second” are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as “first” or “second” may explicitly or implicitly include one or more of that feature. “First” and “second,” etc., are used to distinguish different objects, not to describe a particular order of objects. For example, a first object and a second object are used to distinguish different objects, not to describe a particular order of objects.

[0045] In the description of the embodiments in this application, unless otherwise stated, "multiple" means two or more. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

[0046] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or related scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0047] The term "and / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone.

[0048] Battery packs are typically found in terminal devices such as laptops, tablets, and mobile phones. A battery pack is a complete unit formed by soldering a battery management system (BMS) circuit board and multiple battery cells, then encapsulating them using frames, tape, or other securing devices. The battery cells can be connected in parallel or series and are used to power the terminal device. The BMS circuit board manages and maintains each battery cell, monitoring its status to prevent overcharging and over-discharging, thereby extending the cell's lifespan.

[0049] Figure 1 An exemplary schematic diagram of the internal structure of a battery pack is shown.

[0050] like Figure 1 As shown, the battery pack may include a BMS circuit board 101, battery cells 102, 103, and 104. Battery cells 102, 103, and 104 can all be soldered to the BMS circuit board 101 via connectors. Taking battery cell 102 as an example, battery cell 102 can be soldered to the BMS circuit board 101 via connectors 105a and 105b. Furthermore, the BMS circuit board 101 may also contain protective devices such as a fuse 106, a battery management controller 107, and secondary protection devices 108. These components can be used to monitor the battery cell status and implement overvoltage protection, overcurrent protection, and overtemperature protection measures.

[0051] To facilitate understanding, the relevant terms involved in the embodiments of this application will first be explained.

[0052] Overvoltage protection is a protection method that disconnects the power supply or reduces the voltage of the controlled equipment when the voltage of the protected line exceeds a set threshold.

[0053] Overcurrent protection is a protective mechanism that activates when the current in the protected circuit exceeds a set threshold, preventing damage to the battery cells or load components due to excessive current.

[0054] Over-temperature protection refers to the automatic disconnection of the circuit when the temperature in the protected circuit exceeds a certain threshold, thus protecting the circuit from damage caused by high temperature.

[0055] In summary, protection devices can monitor the status of the protected circuit. When parameters such as current and voltage in the circuit become abnormal, the circuit can be disconnected in time to prevent further damage to the components in the circuit.

[0056] Circuit protection can be designed as a two-stage protection system. Taking overcurrent protection as an example, the protection device can include a primary overcurrent protection unit and a secondary overcurrent protection unit. Generally, the current threshold of the primary overcurrent protection is lower than that of the secondary overcurrent protection. When the current in the circuit exceeds the current threshold of the primary overcurrent protection, the primary overcurrent protection unit can disconnect the circuit. If the primary overcurrent protection unit fails, it cannot disconnect the circuit; the secondary overcurrent protection unit can only disconnect the circuit after the current increases to the threshold of the secondary overcurrent protection.

[0057] Figure 2 An exemplary schematic structural diagram of a battery pack is shown.

[0058] refer to Figure 2 , Figure 2 It includes a first charging / discharging port P+, a second charging / discharging port P-, a battery cell unit 201, a primary switching unit 202, a secondary switching unit 203, a primary control unit 204, and a secondary control unit 205. The first charging / discharging port P+ and the second charging / discharging port P- can be used for electrical connection between the load in the terminal device and the battery cell unit 201.

[0059] It should be noted that the electrical connection between A and B in the embodiments of this application can be understood as a direct electrical connection between A and B, or as an electrical connection between A and B through other components. No specific form is limited.

[0060] The cell unit 201 may include one or more cells, which may be connected in series or in parallel. The cell unit 201 can be used to supply power to the load connected to the battery pack.

[0061] The primary switch unit 202 and the secondary switch unit 203 can be connected in series and are both connected to the positive terminal of the battery cell unit 201, forming a circuit with the battery cell unit 201 and the load. Both the primary switch unit 202 and the secondary switch unit can be used to control the circuit to turn on or off.

[0062] The battery pack may also include a primary control unit 204 and a secondary control unit 205. The primary control unit 204 can be used to detect the current and voltage in the cell circuit and control the switching of the primary switching unit 202. The secondary control unit 205 can be used to detect the current and voltage in the circuit and control the switching of the secondary switching unit 203.

[0063] The following describes an exemplary circuit for a battery pack. Figure 3 An exemplary circuit diagram of a battery pack is shown.

[0064] Can be combined Figure 2 ,refer to Figure 3The battery cell unit 201 may include two battery cells: Cell1 and Cell2. Exemplarily, the primary switching unit 202 may include two metal-oxide-semiconductor field-effect transistors (MOSFETs), i.e., MOS transistors. MOS transistors can be divided into NMOS transistors and PMOS transistors. The primary switching unit 202 includes two NMOS transistors, Q1 and Q2.

[0065] An NMOS transistor consists of a source, a gate, a drain, and a substrate. The gate is separated from the source and drain by a layer of insulating oxide. The switching principle of an NMOS transistor is as follows: When no voltage is applied between the gate and source, the NMOS transistor is in the off state. At this time, there is no conductive path between the source and drain, and current cannot flow, equivalent to the switch being open. When a positive voltage is applied between the gate and source, a conductive path is formed under the gate, making the source and drain conductive. At this time, current can flow smoothly, equivalent to the switch being on.

[0066] When an NMOS transistor is in the ON state, the resistance between its source and drain is relatively low, enabling low-impedance conduction. NMOS transistors have a fast switching speed, making them suitable as protection devices for circuits. Furthermore, NMOS transistors require low drive voltages, facilitating low-voltage operation of integrated circuits.

[0067] The secondary switching unit 203 may include a three-terminal fuse F1. The primary control unit 204 may be... Figure 3 U1, which can be called a fuel gauge, may include a battery management integrated circuit (BMIC). The BMIC is a key component of the BMS. The BMIC integrates multiple functions, such as battery cell voltage monitoring, current measurement, temperature monitoring, battery protection (overcharge, over-discharge, over-temperature, short circuit protection, etc.) and a communication interface.

[0068] U1 may include a charging control pin CHG, a discharging control pin DSG, a power supply pin BAT, a voltage measurement pin C2, a voltage measurement pin C1, a ground pin VSS, current detection pins S+ and S-, and a fuse control pin FS1. The secondary control unit 205 can be... Figure 3 U2 can be referred to as a secondary protection integrated circuit, which may include a fuse control pin FS2, a voltage monitoring pin V1, and a voltage monitoring pin V2.

[0069] It should be understood that, Figure 3The number of pins shown is merely an example; U1 and U2 may have more or fewer pins, and this application embodiment does not limit this.

[0070] The following is about Figure 3 The connection relationship between the pins of U1 and U2 and other components is explained.

[0071] refer to Figure 3 Optionally, the DSG pin of U1 can be electrically connected to the gate of Q2 in the first-stage switching unit. The CHG pin can be electrically connected to the gate of Q1. The FS1 pin can be electrically connected to F1. The BAT pin can be electrically connected to the positive terminal of cell 2, and cells 1 and 2 can supply power to U1 through the BAT pin. The C2 pin can be electrically connected to the positive terminal of cell 2. The C1 pin can be electrically connected to the positive terminal of cell 1. The VSS pin can be electrically connected to the negative terminal of cell 1 and grounded. The S+ and S- pins can be connected across the current sensing resistor RS.

[0072] The FS2 pin of U2 can be electrically connected to the three-terminal fuse F1. The V2 pin can be electrically connected to the positive terminal of cell 2. Cells 1 and 2 can supply power to U2 through the V2 pin. The V1 pin can be electrically connected to the positive terminal of cell 1. U2 can be grounded the same as U1.

[0073] In one possible implementation, U1 can perform a primary protection function. U1 can detect the voltage of cell 2 via pins C2 and C1, and the voltage of cell 1 via pins C1 and VSS. U1 can also detect the voltage of RS via pins S+ and S-. Since the resistance of RS is fixed, U1 can determine the magnitude of the current flowing through cell 1 and cell 2 in the circuit based on the voltage across RS using Ohm's law. When U1 detects overvoltage or overcurrent in cell 1 or cell 2, it can control Q1 and Q2 to disconnect the circuit via pins CHG and DSG. U1 can control the on / off state of Q1 via pin CHG during cell charging.

[0074] For example, during the charging process of the battery cells, Q1 is turned on, and the current flows from P+ through Q1 to battery cells 2 and 1. If an overvoltage or overcurrent occurs at this time, U1 can send a control signal to Q1 through the CHG pin, Q1 will disconnect the charging circuit, and the current cannot flow from the P+ port through Q1 to battery cells 2 and 1, thus realizing the function of the protection circuit.

[0075] During cell discharge, Q2 is turned on, and the current in the circuit flows from cell 1 and cell 2 through Q2 to the P+ port. If U1 detects overvoltage or overcurrent in the circuit during discharge, it can send a control signal to Q2 via the DSG pin to turn off Q2 and disconnect the discharge circuit. Current can no longer flow from the cell unit through Q2 to the P+ port, thus achieving first-level overvoltage and overcurrent protection during the discharge process.

[0076] If U1 fails and the first-level protection is not implemented, U2 can still perform the second-level protection. U2 can detect the voltage of cell 2 through the V1 and V2 pins, and detect the voltage of cell 1 through the V2 pin and the ground pin. When U2 detects an overvoltage, it can control the three-terminal fuse F1 to blow through the FS2 pin, thereby breaking the circuit and realizing the second-level overvoltage protection.

[0077] Since the three-terminal fuse F1 is connected in series in the charging and discharging circuit, F1 itself can also blow after the circuit is subjected to a large current for a period of time, thus realizing the two-stage overcurrent protection of the circuit.

[0078] Optionally, the circuit may also include mini-breakers, which can be connected in series with each cell. For example... Figure 3 As shown, miniature circuit breaker 301 can be connected in series next to cell 1, and miniature circuit breaker 302 can be connected in series next to cell 2. When the current flowing through the miniature circuit breaker increases rapidly, the miniature circuit breaker can disconnect the circuit due to its structure. For example, the miniature circuit breaker may include a bimetallic strip structure composed of two metals with different coefficients of thermal expansion. When the current flowing through the bimetallic strip exceeds a set value, the bimetallic strip will deform differently due to the difference in its coefficients of thermal expansion. This deformation will cause the bimetallic strip to break contact, thereby cutting off the circuit. This can also achieve two-stage overcurrent and overtemperature protection for the circuit.

[0079] Based on the above Figures 1 to 3 The description of the battery pack shows that the battery cells and circuit boards are fixed together. This integrated battery pack typically occupies a large space and can interfere with other components such as circuit boards and structural parts within the electronic device. This reduces the flexibility of the internal architecture stacking of electronic devices using the battery pack, hindering the evolution of products towards miniaturization and thinner designs. Furthermore, since the battery pack is assembled from components such as battery cells and circuit boards, the number of cells connected in series within the pack is usually fixed. This makes it difficult for the battery pack to meet the demands of end devices for variable numbers of cells connected in series, demands typically arising from factors such as range and cost.

[0080] To address the problems arising from the integrated and fixed nature of battery packs, this application provides an electronic device that may include a battery system. In this system, the battery management system and battery cells, which are traditionally encapsulated within a battery pack, are separated. The battery management system can be integrated onto a motherboard, while the battery cells can be moved and assembled individually, and their positions can be adjusted according to the structural needs of the electronic device.

[0081] However, the integration of the battery management system onto the motherboard, with multiple battery cells soldered or snapped onto it via connectors, also introduces new challenges. Typically, the use case for connecting multiple cells in series to the motherboard is in power banks. In power banks, the cells are usually soldered to one side of the circuit board, and the area where the cell tabs are soldered and the current-carrying area are isolated and independent from other circuit areas on the board. Furthermore, the interlayer spacing in power banks is relatively large, making interlayer short circuits less likely. However, for motherboards in digital products, due to the numerous layers and small interlayer spacing of the printed circuit board (PCB), when multiple cells are snapped onto the motherboard, the current-carrying area of ​​the cells may interfere with other circuit areas on the motherboard, and interlayer short circuits are more likely to occur. In this case, the single high-side protection method, similar to that in the aforementioned battery pack where only a protective device is placed at the positive terminal of the cell, cannot meet the new protection requirements.

[0082] Therefore, in the battery system provided in this application embodiment, protection devices can also be placed at the positive and negative terminals of the battery cell to achieve multi-sided protection of the battery cell in order to deal with various possible short circuit phenomena.

[0083] In addition to the location of the protection device, this application proposes an update to the selection of the protection device.

[0084] In typical multi-cell battery management schemes, there are generally four types of protection devices: fuel gauge, secondary protection integrated circuit, three-terminal fuse box, and miniature circuit breaker.

[0085] The fuel gauge can be used to perform primary overvoltage and overcurrent protection. Secondary protection integrated circuits and three-terminal fuses can be used to perform secondary overvoltage protection. Three-terminal fuses and miniature circuit breakers can be used to perform secondary overcurrent and overtemperature protection.

[0086] Miniature circuit breakers are expensive and have poor structural reliability. In application scenarios, vibration or drops may cause the bimetallic strip to break, leading to abnormal battery power loss. Three-terminal fuses are one-time fuses; once triggered, they cannot be reset, causing battery damage and requiring replacement, which is very cumbersome. Furthermore, in this application, the three-terminal fuse is placed on the motherboard along with the battery management system. If the three-terminal fuse blows on the motherboard, it may also damage the motherboard, resulting in higher repair costs for motherboard replacement. Therefore, this application improves the battery system structure and the protection devices within the battery system.

[0087] The following description, with reference to the accompanying drawings, uses a battery containing two cells as an example to illustrate the battery system of the electronic device provided in the embodiments of this application.

[0088] Figure 4 An exemplary schematic diagram of a battery system is shown.

[0089] like Figure 4 As shown, the battery system may include cell 401 and cell 402. Cell 401 and cell 402 are connected in series and can be electrically connected to the load in the terminal device through the P+ port and the P- port to form a circuit.

[0090] The battery system may also include a primary switching unit 403 and a secondary switching unit 404. The primary switching unit 403 and the secondary switching unit 404 can be used to disconnect the circuit for circuit protection. The primary switching unit 403 can be connected in series between the positive terminal of the cell 402 and the P+ port. The secondary switching unit 404 can be connected in series between the cell 401 and the P- port.

[0091] In addition, the battery system may also include a primary control unit 405 and a secondary control unit 406. The primary control unit 405 can detect the current and voltage in the circuit and control the on / off state of the primary switching unit 403. The secondary control unit 406 can also detect the voltage and current in the circuit and control the on / off state of the secondary switching unit 404. The primary control unit 405 and the primary switching unit 403 can be used to implement primary protection of the circuit at the positive terminal of the battery cell. The secondary control unit 406 and the secondary switching unit 404 can be used to implement secondary protection of the circuit at the negative terminal of the battery cell.

[0092] The primary control unit 405, primary switching unit 403, secondary control unit 406, and secondary switching unit 404 can be included in the battery management system, and these components can be mounted on the main board 407. Battery cells 3 and 4 can be soldered to the main board 407 via connectors. Figure 4As shown, battery cell 3 can be connected to motherboard 407 via connector 408. Battery cell 4 can be connected to motherboard 407 via connector 409.

[0093] In this way, the battery management system in the aforementioned battery pack can be integrated onto the motherboard. The battery cells in the battery pack can be connected to the motherboard via connectors, eliminating the need to integrate them into a single battery pack. This saves space and resolves the conflict between the circuit board and battery structure in stacked architectures. Furthermore, the battery cell components can be moved and assembled individually, and the position of the cells can be adjusted according to the needs of the overall device structure, making the overall architecture design more flexible.

[0094] By connecting a circuit-breaking protection device in series with the positive terminal of the highest-connected battery cell and the negative terminal of the lowest-connected battery cell, various short-circuit problems, including inter-layer short circuits on the PCB, can be solved, thus increasing the protection range for the battery cells.

[0095] Both the primary switch unit 403 and the secondary switch unit 404 can be resettable protection periods. When the primary switch unit 403 is disconnected due to the execution of circuit protection function, it can be reconnected by the primary control unit 405 to restore circuit continuity. Similarly, when the secondary switch unit 404 is disconnected due to the execution of circuit protection function, it can be reconnected by the secondary control unit 406. This avoids battery or equipment failure and motherboard damage caused by battery protection, thus reducing maintenance costs.

[0096] Figure 4 The diagram also shows two local circuits, regions 410 and 411. For details about regions 410 and 411, please refer to the relevant descriptions below. They will not be repeated here.

[0097] The schematic circuit of this battery system is described below, which can be combined with... Figure 4 ,refer to Figure 5 .

[0098] Cell 401 can be referred to as cell 3. Figure 5 The label is Cell3. Cell 402 can be referred to as Cell 4. Figure 5 The cell is labeled Cell4. Cells 3 and 4 can be connected to the motherboard via connectors. The primary switching unit 403 may include two NMOS transistors Q3 and Q4. The secondary switching unit 404 may include two NMOS transistors Q5 and Q6. The primary control unit 405 can be a fuel gauge. Figure 5 The identifier U1 is still used. The secondary control unit 406 can provide secondary protection for the integrated circuit. Figure 5 It can be identified by U3. Both U1 and U3 can include multiple pins.

[0099] The following describes the pins of U1 and U3 and their connections to components in the circuit.

[0100] U1 may include a charging control pin CHG, a discharging control pin DSG, a power supply pin 1BAT, a power supply pin 2VCC, a voltage measurement pin C1, a voltage measurement pin C2, a ground pin VSS, current measurement pins S+ and S-, and a detection adapter pin PACK.

[0101] U3 may include overvoltage detection / power supply pin VDD, overcurrent detection pins GND and VI, charging control pin DO, discharging control pin CO, and adapter detection pin VM.

[0102] In U1, the DSG pin can be electrically connected to the gate of Q3. The CHG pin can be electrically connected to the gate of Q4. The BAT pin can be electrically connected to the positive terminal of cell 4. The VCC pin can be electrically connected to a point between Q3 and Q4. The C2 pin can be electrically connected to the positive terminal of cell 4, and the C1 pin can be electrically connected to the negative terminal of cell 4. The VSS pin can be electrically connected to the negative terminal of cell 3, and U1 can also be grounded through the VSS pin. The PACK pin can be electrically connected to the P+ port.

[0103] The circuit may also include a current-sensing resistor RS. RS can be connected in series between cell 3 and the secondary switching unit 404. The S+ and S- pins of U1 can be electrically connected to the two ends of RS, respectively.

[0104] In U3, the VDD pin can be electrically connected to the positive terminal of cell 3, and the GND pin is grounded (GND1) and connected to one end of RS. The VI pin is connected to the other end of RS. U3 can detect the voltage across RS through the GND and VI pins, and determine the current flowing through RS based on its resistance and Ohm's law, thus achieving current detection. The DO pin in U3 can be electrically connected to the gate of Q5, and the CO pin can be electrically connected to the gate of Q6. The VM pin can be electrically connected to the P-port.

[0105] U1 and U3 can share GND1 and current sensing resistor RS, which eliminates the need for the current sensing resistor in U3 and reduces the link impedance during charging and discharging.

[0106] For example, U1 can detect the voltage across cell 4 via pins C2 and C1, and detect the voltage across cell 3 via pins C1 and VSS. It can also detect the voltage across RS via pins S+ and S-, and determine the current flowing through RS based on Ohm's law. In this way, U1 can monitor the voltage and current of cells 3 and 4 in the circuit.

[0107] U3 can measure the voltage of cell 3 via the VDD and GND pins. U3 can also detect the voltage across RS via the GND and VI pins and determine the loop current based on Ohm's law. In this way, U3 can monitor the voltage and current of cell 3.

[0108] Optionally, in Figure 5 In the circuit shown, U1 can be used to perform the primary protection function mentioned above, and U3 can be used to perform the secondary protection function mentioned above. Alternatively, U1 can be used to perform the secondary protection function mentioned above, and U3 can be used to perform the primary protection function mentioned above. This application embodiment does not limit this specific implementation.

[0109] For ease of description, we will assign U1 to perform the primary protection function and U3 to perform the secondary protection function. The following section uses overcurrent protection as an example to illustrate the timing sequence of U1 and U3 performing their protection functions.

[0110] Both U1 and U3 can monitor the current in the circuit. For easy distinction, the overcurrent detection current threshold set in U1 is denoted as Ia, and the overcurrent detection current threshold set in U3 is denoted as Ib.

[0111] During the discharge or charging process of the battery cell, U1 is used to detect the current Ic flowing through RS. If Ic is greater than Ia, U1 sends a control signal to the first-stage switching unit 403 to disconnect the first-stage switching unit, thereby breaking the circuit and achieving overcurrent protection. Similarly, U3 is also used to detect the current Ic flowing through RS. If U1 fails, that is, if Ic is greater than Ia, U1 cannot disconnect the circuit in time, and the battery cell continues to charge or discharge until Ic is greater than Ib. Then U3 sends a control signal to the second-stage switching unit 404 to disconnect the second-stage switching unit 404, thereby breaking the circuit and achieving overcurrent protection.

[0112] Specifically, during the cell discharge process, Q3 in the primary switching unit 403 is turned on, and Q5 in the secondary switching unit 404 is turned on. Current flows from the cell through Q3 to the P+ port, through the load, then from the P- port through Q5 through RS, and finally back to the cell. During this process, U1 performs primary overcurrent protection by sending a control signal to Q3 via the DSG pin to turn off Q3, thus disconnecting the discharge circuit. If U1 fails, U3, when performing secondary overcurrent protection, can send a control signal to Q5 via the DO pin to turn off Q5, thus disconnecting the discharge circuit.

[0113] During the cell charging process, Q4 in the primary switching unit 403 is turned on, and Q6 in the secondary switching unit 404 is turned on. The current in the circuit is supplied by P.

[0114] The + port flows to the battery cell through Q4 to charge the cell. Then, from the cell, through RS, and through Q6, the current flows to the P- and P+ ports to form a circuit. When U1 performs first-level overcurrent protection, a control signal can be sent to Q4 via the CHG pin to turn off Q4, thus disconnecting the charging circuit. If U1 fails and U3 performs second-level overcurrent protection, Q6 can be turned off via the CO pin to disconnect the charging circuit.

[0115] Furthermore, after Q3 is turned off, U1 can control Q3 to turn on via the DSG pin; after Q4 is turned off, U1 can control Q4 to turn on via the CHG pin. After Q5 is turned off, U3 can control Q5 to turn on via the DO pin; and after Q6 is turned off, U3 can control Q6 to turn on via the CO pin. In this way, by controlling the NMOS transistor's on and off via software or hardware—where U1 can control the NMOS transistor via software and U3 can control it via hardware—recoverable protection of the circuit can be achieved, preventing battery failure due to fuse blowouts or other reasons during circuit protection.

[0116] In some examples, after the U1 trigger circuit protection is activated, the electronic device can deactivate the protection state of U1 via the PACK pin, allowing the electronic device to resume operation. The PACK pin can also be used to wake up U1 when the battery cell is undervoltage, enabling U1 to operate normally and perform operations such as charging. After the U2 trigger circuit protection is activated, the electronic device can deactivate the protection state of U3 via the VM pin, and can also wake up U3 to enable it to operate normally when the battery cell is undervoltage and unable to supply power.

[0117] In the aforementioned overcurrent protection process, the overcurrent protection current threshold Ia of U1 should be less than the overcurrent protection current threshold Ib of U3. This allows U1 to perform primary overcurrent protection, while U3 performs secondary overcurrent protection when U1 fails, achieving dual overcurrent protection for the battery. Similarly, in overvoltage protection, the overvoltage protection voltage threshold of U1 should also be less than the overvoltage protection voltage threshold of U3.

[0118] Therefore, due to the requirements for current and voltage thresholds, the selection of U1 and U3 in the protection circuit design has additional requirements and is relatively complicated. Generally, U1, as a BMIC, has software-adjustable current and voltage thresholds. However, the protection threshold of U3 is usually fixed. Furthermore, since U1 and U3 share the same current sensing resistor RS in the battery system provided in this application, U3 cannot change its actual protection threshold by changing the resistance value of RS. Therefore, in circuit design, the threshold range requirement for U3 is relatively high, and the selection range for U3 is relatively small.

[0119] Based on this, the embodiments of this application also propose improvements to the circuit design of U3, by improving the threshold range of U3 through some circuit elements, so that the protection threshold of U3 is adjustable, thereby broadening the selection range of U3.

[0120] Figure 6A An enlarged view of a portion of the circuitry of U3 is shown as an example.

[0121] like Figure 6A As shown, the VDD pin of U3 is electrically connected to the positive terminal of cell 3, and the GND and VI pins are connected to the two ends of RS. U3 detects the voltage of cell 3 through the VDD and GND pins, and detects the current of RS through the GND and VI pins.

[0122] In practice, the current detection across RS in both U1 and U3 is achieved by detecting the voltage across RS. Since the resistance of RS is known to both U1 and U3, the current flowing through RS can be determined simply by detecting the voltage across RS. Therefore, the overcurrent protection threshold Ib set in U3 mentioned above can be implemented in one possible way by setting a voltage threshold.

[0123] For example, the overcurrent protection voltage threshold of U3 can be denoted as Vb. When U3 detects that the voltage Uc across RS is greater than Vb, it can be determined that the current of RS is too large, exceeding the current protection threshold, and thus further overcurrent protection operation is performed. Based on Ohm's law, the relationship between Vb and Ib can be exemplarily represented as: Vb = Ib * RS.

[0124] Based on this, embodiments of this application can change the overcurrent protection threshold of U3 by adjusting the actual voltage value detected by U3. (See also...) Figure 6B . Figure 6B An exemplary embodiment of the U3 partial improvement circuit provided in this application is shown.

[0125] like Figure 6B As shown in region 601, two resistors R1 and R2 can be connected in parallel across RS. In this connection, the sum of the voltages across R1 and R2 equals the voltage across RS. Then, the GND and VI pins of U3 are switched from across RS to across R2. This makes the voltage actually detected by U3 the voltage across R2. According to the series voltage divider principle, the voltage across R2 is less than the voltage across RS. That is, the voltage actually detected by U3 is less than the voltage across RS. Therefore, when the current flowing through RS reaches Ib and the voltage across RS reaches Vb, the voltage detected by U3 is less than Vb, and the overcurrent protection of U3 will not be triggered. However, when U3 actually detects a voltage of Vb, the voltage across RS has already exceeded Vb, and the current flowing through RS has also exceeded Ib. The overcurrent protection voltage threshold of U3 can be considered as a fixed Vb, while...Figure 6B In this connection configuration, the actual overcurrent protection current threshold of U3 can be denoted as I_th, and the relationship between Vb and I_th can be: Vb = I_th * Rs / (R1 + R2) * R2. Thus, the actual overcurrent protection current threshold of U3 can be adjusted by changing the resistance values ​​of R1 and R2. This application does not limit the specific resistance values ​​of R1 and R2.

[0126] Similarly, the same approach can be used to adjust the voltage protection threshold of U3 for overvoltage detection. For example... Figure 6B As shown in region 602, a diode can be connected in series with the input of the overvoltage detection pin VDD of U3 to increase the overvoltage protection threshold of U3. Each added diode decreases the voltage applied to the VDD pin by Vf. That is, each added diode increases the overvoltage detection threshold of U3 by Vf. Here, Vf is the forward voltage drop across the diode.

[0127] In this way, with the threshold values ​​of U3 fixed, the overvoltage protection detection threshold and overcurrent protection detection threshold can be adjusted, thus enriching the selection range of U3 to adapt to different product needs.

[0128] In summary, the battery system provided in this application separates the circuit management system from the battery cell, integrating the circuit management system onto the motherboard. The battery cell's position is adjusted as needed and it is fastened to the motherboard via connectors. This reduces space occupation and improves the flexibility of the device's internal architecture. The battery system also incorporates protection devices at the positive and negative terminals of the battery cell, enabling circuit disconnection from both terminals and addressing various potential short-circuit phenomena arising from the new architecture. Furthermore, the protection devices used have been adjusted, employing MOSFETs as switching devices to achieve secondary recoverability of the protection circuit, increasing circuit stability and preventing damage to the motherboard or circuitry due to circuit protection actions, thus reducing maintenance costs. Moreover, through circuit design, the detection thresholds for actual overvoltage and overcurrent protection in the secondary control unit are adjustable, enriching the selection of secondary control units and adapting to different product requirements.

[0129] The following section will provide further details on the battery system's capabilities.

[0130] For reference Figure 7 , Figure 7 An exemplary circuit diagram of a battery system provided in an embodiment of this application is shown.

[0131] Figure 7 The battery system shown includes the battery cells, U1, U3, and peripheral devices associated with U1 and U3, which can be referred to in the above description. Figure 5 The description will not be repeated here.

[0132] U1 may also include a detection pin FUSE, and communication pins SCL and SDA.

[0133] The FUSE pin can be used to ground GND2, and the communication pins SCL and SDA can be used to connect to the main control chip via the I2C bus. GND2 is the ground network on the system side where the main control chip is located.

[0134] U1 can communicate with the main control chip via the I2C bus through the SCL and SDA pins, sending parameters such as the cell's charging and discharging status, including voltage, current, and temperature, to the main control chip. Based on the data provided by the fuel gauge U1, the main control chip can assess the battery's current state, such as remaining charge, health status, and cycle life, providing accurate information to the user. When the battery experiences abnormal conditions such as overcharging, over-discharging, overcurrent, or short circuits, the fuel gauge can promptly notify the main control chip, which can then take immediate measures, such as cutting off the battery output, to protect the battery from damage.

[0135] In a battery pack composed of multiple cells, the fuel gauge can perform battery balancing management to ensure that the charge of each cell is consistent, avoiding performance degradation or safety hazards caused by battery imbalance.

[0136] The main control chip can be electrically connected to the charger charger, and the charger charger can also be electrically connected to the battery system. Data from the fuel gauge U1 can also help the main control chip control the charger to achieve optimal charging strategies, such as adjusting charging current and voltage, and determining when to end charging to extend battery life.

[0137] When connected to a charger, the cells in the battery system can discharge to power a load or be charged via the charger. During charging and discharging, the protection devices in the battery system can perform the following functions: charging overcurrent protection, discharging overcurrent protection, cell overvoltage protection, cell undervoltage protection, short circuit protection, charger detection, and 0V charging.

[0138] 1. Overcurrent protection during charging

[0139] Regarding charging overcurrent protection, the operations performed by U1 and U3, and their power-on / off sequences, please refer to the above content. Figure 5 The description will not be repeated here.

[0140] The overcurrent protection threshold of the U1 fuel gauge is configurable via software. The discharge overcurrent protection threshold of the U2 fuel gauge can be adjusted by changing the ratio of the resistance values ​​of R1 and R2 in the voltage divider circuit. For details on the voltage divider circuit, please refer to the section above. Figure 6B The description will not be repeated here.

[0141] In some examples, in the scenario of charging overcurrent protection, if U1 is abnormal and the first-level overcurrent protection cannot be executed, the subsequent charging scenarios can be divided into two categories.

[0142] First, if a smart charger is used to charge the battery cell, the smart charger relies on I2C communication with U1 to obtain the battery's allowable charging current and voltage. Therefore, if U1 malfunctions and the smart charger cannot communicate with U1, charging can stop after a few seconds, and the battery will switch to discharging to avoid overcurrent during charging.

[0143] Second, if a non-smart charger is used and there is no I2C communication with U1, then when the current reaches the secondary overcurrent protection threshold, U3 can shut down Q4 to perform secondary overcurrent protection, thus achieving overcurrent protection.

[0144] In this way, regardless of whether the user's charger is smart or not, the battery system can provide overcurrent protection in the event of a U1 malfunction.

[0145] 2. Discharge overcurrent protection

[0146] Regarding discharge overcurrent protection, the operations performed by U1 and U3, as well as the power-on / off sequence, are basically the same as those for charging overcurrent protection. You can also refer to the above content for further details. Figure 5 The description will not be repeated here.

[0147] In some examples, if the system triggers a discharge overcurrent protection, Q3 is turned off under control, while Q5 is not turned off. In this case, the fuel meter U1 shares the same ground GND2 with the system, and the communication link is normal.

[0148] If the fuel gauge U1 malfunctions, Q3 will be turned off, and U3 will normally keep Q5 on.

[0149] If the fuel gauge U1 malfunctions and Q1 remains open, U3 will detect an overcurrent and keep Q5 off. In this scenario, the potential of GND2 is equivalent to Cell4+. The communication pins SCL and SDA of the fuel gauge U1, which interact with the motherboard, as well as the detection pin FUSE, will be subjected to high voltage. If these pins of U1 are not voltage-resistant, voltage clamping needs to be applied to these networks. Voltage clamping can be referenced... Figure 7 As shown in the middle area 701.

[0150] At this time, Cell4+ will continuously discharge a small current to the VSS of the fuel gauge through these pins. If there is a clamping diode between the VM pin of the U3 adapter and the power supply pin, Cell4+ will continuously discharge to Cell4- through this clamping diode, and the voltage of the power supply pin of U3 will increase, which may trigger the charging overvoltage protection of U3 and cause Q6 to turn off. When the charger is plugged in, U3 can release the protection of Q5 and Q6.

[0151] If the fuel gauge U1 is normal, but Q1 is damaged and short-circuited, the protection logic is the same as the failure scenario above.

[0152] 3. Cell overvoltage protection

[0153] In this embodiment, U1 performs primary protection and U3 performs secondary protection as an example. To ensure that U1 performs protection first, the overvoltage protection threshold of U1 can be configured by software to be lower than the overvoltage protection threshold of U3. If, due to model limitations, it is necessary to increase the overvoltage protection detection threshold of U3, several diodes can be connected in series on the VDD power supply path of U3. In this way, the voltage detected by U3 is the cell voltage minus the voltage drop of the diodes, thereby increasing the overvoltage protection threshold of U3.

[0154] Cell overvoltage protection typically occurs during charging. U1 can detect the voltage of cells 3 and 4. When U1 detects that the cell voltage exceeds its overvoltage protection threshold, it can send a control signal to Q4 to shut down Q4, thus disconnecting the charging circuit and protecting the cells. If U1 malfunctions and cannot disconnect the charging circuit in time, the cell voltage will continue to increase. U3 can detect the voltage of cell 3. When the cell voltage exceeds its overvoltage protection threshold, U3 can send a control signal to Q6 to shut down Q6, thus disconnecting the charging circuit and implementing secondary overvoltage protection.

[0155] 4. Cell undervoltage protection

[0156] In addition to overcurrent and overvoltage protection, the battery system can also perform cell undervoltage protection.

[0157] The undervoltage protection threshold of the U1 power meter can be configured by software, and the U1 can be used to perform first-level undervoltage protection.

[0158] If U3 is used as the secondary undervoltage protection, the undervoltage protection threshold of the selected U3 model needs to be lower than the configured value of U1. If no suitable model is available, the undervoltage protection function of U3 can be disabled. Figure 7 As shown in section 702, the Vsys2 voltage can be connected in series with a diode to the overvoltage detection / power supply pin VDD of U3, where Vsys2 can be obtained by stepping down the AC power supply Vsys1. In this way, the voltage on the VDD pin of U3 will be stabilized at a certain value, supplying power to U3 while avoiding triggering the undervoltage protection of U3.

[0159] 5. Short circuit protection

[0160] During short-circuit protection, the threshold configuration logic and trigger protection action logic of U1 and U3 are the same as those of discharge overcurrent protection. Please refer to the description of discharge overcurrent protection above, which will not be repeated here.

[0161] Both Q3 and Q5 can provide short-circuit protection in P+ / P- short-circuit scenarios. In the Cell3+ / P- short-circuit scenario, Q5, located at the negative terminal of the cell, can also provide short-circuit protection.

[0162] 6. Charger detection function

[0163] If U3 experiences overcurrent or short circuit protection in the discharge direction, Q5 will turn off. In this case, the entire unit can be deactivated by connecting an adapter. When the adapter is connected, Vsys2 on the motherboard powers on, and the charger applies an activation voltage to the battery's P+, thus deactivating the shutdown state of Q5 and Q6.

[0164] 7. 0V charging function

[0165] When both battery cell voltages are 0V, both Q4 and Q6 are off. Since the fuel gauge U1 has no return path, it cannot operate in a 0V charging state, and therefore cannot turn on Q4, causing the adapter to be unable to supply power to U3 and thus prevent U3 from turning on Q6.

[0166] In this embodiment, U3 can be powered by the Vsys2 voltage on the motherboard side to release the over-discharge state and turn on Q5 / Q6. This allows current to flow through P+, VCC pin, VSS pin, P-, and P+, forming a loop. The adapter can then power U1 through the VCC pin. The fuel gauge U1 subsequently controls Q4 to conduct, completing the pre-charging of the battery cell.

[0167] In this way, for scenarios where the secondary protection IC is used for series battery protection, the redundant power supply function of the protection device can be added to ensure that the device can normally open the charging and discharging tube in the case of cell undervoltage and 0V.

[0168] In the above Figure 7 The descriptions all use the example of U1 executing the protection action before U3. In some examples, if an abnormality occurs in U3 and its peripheral circuits, causing U3 to execute the discharge protection action before U1 and resulting in a system power-down, the fuel gauge U1 can record this event. Figure 7 In this configuration, the detection pin FUSE of U1 is grounded to GND2. Therefore, when U3 turns off Q5, Q3 / Q4 remain on, and the voltage at GND2 is equal to the voltage at P+. Thus, if U1 detects a high-level input at the FUSE detection pin, it can identify a malfunction of U3, reducing the difficulty of troubleshooting the battery system.

[0169] In addition, the U1 can also adjust the cells in the battery system to extend the working life of the cells.

[0170] In some examples, when the cell voltage exceeds 3.3V, U3 is powered by approximately 3uA from cell 3. This can lead to a voltage difference between cell 3 and cell 4 in long-term storage scenarios. Therefore, when the fuel gauge U1 is powered on, U1 can discharge cell 4 evenly to ensure that the voltages of the two cells remain consistent.

[0171] In other examples, U1 can also sample the cell voltages of cells 3 and 4, requiring compensation of the link impedance from the voltage sampling point to the cell tabs of each cell. U1 can calculate and compensate for this impedance. In this way, U1 can obtain the true value of the cell voltage when detecting the voltage, improving the accuracy of the detection.

[0172] In summary, this allows the Battery Management System (BMS) to be integrated onto the motherboard, with the battery cell tabs fastened to the motherboard via connectors, thus changing the battery system architecture while achieving multiple protection functions.

[0173] It is worth noting that although the battery system provided in this application embodiment has protective devices placed at both the positive and negative terminals of the cell, the circuit still has a short-circuit risk. (See reference...) Figure 4 , Figure 4 Regions 410 and 411 shown can be referred to as the protection blind zones of the battery system provided in this application embodiment. If a short circuit occurs in regions 410 and 411, the secondary switching unit 404 and the primary switching unit 403 cannot disconnect the short-circuit loop, the protection device fails, and the main board or battery cell is damaged. Therefore, in scenarios where the battery management system is placed on the main board, there are certain requirements for the actual circuit wiring.

[0174] Among them, Q3 / Q4 need to be as short as possible from the positive terminal of the connector of cell 4, and Q5 / Q6 need to be as short as possible from the negative terminal of the connector of cell 3, in order to shorten the trace length of the negative terminal of cell 3 and the positive terminal of cell 4 on the motherboard and reduce the probability of interlayer short circuit.

[0175] The current sensing resistor RS and the charging / discharging transistors Q5 and Q6 of U3 need to be close to the negative terminal of the cell 3 connector, while the charging / discharging transistors Q3 and Q4 of U1 need to be close to the positive terminal of the cell 4 connector.

[0176] The positive terminal of cell 3 and the negative terminal of cell 4 should be kept away from the P+ network in the motherboard wiring structure. They can be staggered between layers of the P+ network to avoid inter-layer short circuits. The wiring of the positive network of each cell should also be staggered between layers and should not refer to other networks other than P-.

[0177] Based on this, the battery system provided in this application embodiment realizes the use of a single-cell protection circuit to perform secondary protection at the negative terminal of the cell, realizing multiple protection functions such as recoverable secondary overcurrent and overvoltage. This allows the circuit to be placed on a motherboard with a small interlayer thickness, realizing the management function of the cells outside the motherboard, and avoiding the problem of short circuit between motherboard PCB layers.

[0178] Compared to traditional battery packs, it eliminates the need for high-cost, one-time-use three-terminal fuses and micro-circuit breakers with poor structural reliability, significantly reducing costs and link impedance.

[0179] After the positive terminal of cell 4 and the negative terminal of cell 3 are connected to the motherboard connector, the links are connected in series with the protection MOSFETs U1 / U3 over a short distance, providing dual protection against abnormalities such as short circuits within the motherboard. Simultaneously, the connector engagement position of the cells is decoupled from the fuel gauge circuit, allowing for diverse layouts of the cells and motherboard, making it widely applicable to new product architectures, such as... Figure 4 The scene shown depicts a motherboard placed between two battery cells.

[0180] The circuitry of the battery system provided in this application embodiment can also be modified. Figure 8 A circuit diagram of another battery system provided in an embodiment of this application is shown.

[0181] like Figure 8 As shown, in one possible implementation, there is a GND1 between the secondary switching unit and GND2.

[0182] Because there is a second ground between the secondary switch unit and the P-port, and GND1 between the secondary switch unit and GND2, the secondary switch unit is located on the line outside of GND1 to GND2, and GND1 and GND2 are no longer separated by the secondary switch unit.

[0183] When an electronic device is operating, its motherboard needs to communicate with the primary control unit to obtain the battery cell's operating status. This information is used to manage the charging and discharging of the device and to provide the user with information about the battery level. If the reference ground GND1 of the primary control unit and the reference ground GND2 of the motherboard are isolated by a secondary switching unit, in some scenarios, the disconnection of the secondary switching unit will cause a difference in potential between GND1 and GND2. This will lead to communication signal disorder between the motherboard and the primary control unit, preventing them from communicating.

[0184] Adjusting the positions of GND1 and the secondary switch unit ensures that GND1 connected to the primary control unit and GND2 on the motherboard side are not disconnected by the secondary switch unit. This allows the potentials of GND1 and GND2 to remain almost identical, enabling the battery management circuit to maintain communication with the motherboard at all times.

[0185] Specifically, when U3 triggers the protection action and disconnects Q5 / Q6, it will not affect the potential relationship between GND1 and GND2. Since the resistance of RS is negligible, the potentials of GND1 and GND2 are almost the same. Therefore, in various scenarios, no matter how U3 operates, it will not affect the communication and signal control between the fuel gauge U1 and the main control chip on the motherboard.

[0186] The battery systems described above are all based on the example of two battery cells. In reality, a battery system can include more battery cells. Figure 9 A circuit diagram of another battery system provided in an embodiment of this application is shown.

[0187] like Figure 9 As shown, other parts of the circuit can be referenced from the above content. Figure 7 The description.

[0188] In one possible implementation, different from Figure 7 The fuel gauge U1 can also be extended with two pins, C3 and C4. In addition to cells 3 and 4, cell 5 can also be attached to the motherboard via a connector. The positive terminal of the cell 5 connector can be electrically connected to pin C4, and the negative terminal can be electrically connected to pin C3, allowing cell 5 to be connected in series with cells 4 and 3. This expands the application scenario of two strings of cells in the above embodiment to multiple strings, enabling adjustable cell count. This application does not limit the specific number of cells in the battery system.

[0189] Furthermore, the secondary protection IC described in the above embodiments can also be improved. In the above, the secondary protection IC can be referred to as U3. U3 can independently monitor the voltage of cell 3 and is independently powered by cell 3.

[0190] The plurality of series-connected cells include at least a head cell and a tail cell, the second voltage detection pin is connected to the positive terminal of the head cell, and the second current detection pin is electrically connected to the negative terminal of the tail cell.

[0191] In this way, the number of battery cells in electronic devices can be adjusted, allowing the electronic devices to adjust the number of battery cells according to different battery life requirements.

[0192] In addition to its detection function, the second control unit also has a second voltage detection pin that can be connected to the positive terminal of a battery cell, and a second current detection pin that can be connected to the negative terminal of a battery cell, thereby enabling the battery cell to supply power to the second control unit.

[0193] If the battery cell unit comprises multiple cells connected in series, the second control unit can be powered by these cells. The second voltage detection pin is connected to the positive terminal of the head cell, and the second current detection pin is electrically connected to the negative terminal of the tail cell. This increases the supply voltage of the second control unit, thereby increasing the output voltage. This allows the second charging control pin and the second discharging control pin of the second control unit to output higher control voltages, enabling the driving of switching units with higher trigger thresholds. This expands the selection range of the second switching units and facilitates the architecture design of electronic devices.

[0194] Specifically, such as Figure 10 As shown, Figure 10 U4, as shown, can monitor the voltages of cells 3 and 4 separately. The power supply pin VDD of U4 is connected to the positive terminal of cell 4, and its supply voltage is the series voltage between cells 4 and 3. Therefore, U4 can drive a higher voltage for the MOSFET than U1 can. This allows for a wider selection range for Q5 and Q6 when using U4 in the circuit, enabling the complete product to meet more requirements.

[0195] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application 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 scope of the technical solutions of the embodiments of this application.

Claims

1. An electronic device, characterized in that, The electronic device includes: a motherboard (407), a battery management circuit, a battery cell unit (201), a first charging / discharging port (P+), and a second charging / discharging port (P-); The battery management circuit includes a first control unit (405), a second control unit (406), a first switching unit (403), and a second switching unit (404); The battery management circuit is located on the motherboard (407), the battery cell unit (201) is fastened to the motherboard (407) through a connector, and the battery cell unit (201) is electrically connected to the battery management circuit through the connector; The first charging / discharging port (P+) is electrically connected to the positive terminal of the battery cell (201), and the second charging / discharging port (P-) is electrically connected to the negative terminal of the battery cell (201); the first switching unit (403) is connected in series between the first charging / discharging port (P+) and the positive terminal of the battery cell (201), and the second switching unit (404) is connected in series between the second charging / discharging port (P-) and the negative terminal of the battery cell (201); The first control unit (405) is electrically connected to the first switch unit (403) and is used to control the first switch unit (403) to be turned on or off. The second control unit (406) is electrically connected to the second switch unit (404) and is used to control the second switch unit (404) to be turned on or off.

2. The electronic device according to claim 1, characterized in that, The first control unit (405) includes a first charging control pin, a first discharging control pin, a first voltage detection pin, a first grounding pin, and a first current detection pin; the first switching unit (403) includes a first charging switch and a first discharging switch; The first charging control pin is electrically connected to the control terminal of the first charging switch, and the first discharging control pin is electrically connected to the control terminal of the first discharging switch. The first voltage detection pin is electrically connected to the battery cell unit, and the first voltage detection pin is used to detect the voltage of the battery cell unit; The first current detection pin is used to detect the charging and discharging current of the battery cell. The first grounding pin is used to connect to the first ground.

3. The electronic device according to claim 1 or 2, characterized in that, The second control unit (406) includes a second charging control pin, a second discharging control pin, a second voltage detection pin, and a second current detection pin; the second switching unit (404) includes a second charging switch and a second discharging switch. The second charging control pin is electrically connected to the control terminal of the second charging switch, and the second discharging control pin is electrically connected to the control terminal of the second discharging switch. The second voltage detection pin is electrically connected to the battery cell unit, and the second voltage detection pin is used to detect the voltage of the battery cell unit; The second current detection pin is used to detect the charging and discharging current of the battery cell. A second ground is connected between the second switching unit (404) and the second charging / discharging port.

4. The electronic device according to claim 3, characterized in that, The second switching unit (404) is connected to the first ground by the second ground.

5. The electronic device according to claim 3 or 4, characterized in that, The second voltage detection pin of the second control unit (406) is also used to connect to the system voltage.

6. The electronic device according to any one of claims 1-5, characterized in that, The first parameter threshold is different from the second parameter threshold; the first parameter threshold is the threshold that triggers the first control unit (405) to control the state change of the first switch unit (403), and the second parameter threshold is the threshold that triggers the second control unit (406) to control the state change of the second switch unit (404).

7. The electronic device according to any one of claims 1-6, characterized in that, The battery management circuit further includes a first circuit (602), which includes one or more diodes connected in series and is located between the positive terminal of the cell and the second voltage detection pin.

8. The electronic device according to any one of claims 1-6, characterized in that, The battery management circuit also includes a current sensing resistor and a voltage divider network (601), the voltage divider network (601) including multiple series resistors; the current sensing resistor is connected in series between the cell unit and the second switching unit (404), and the voltage divider network (601) is connected in parallel with the current sensing resistor.

9. The electronic device according to any one of claims 1-8, wherein the battery cell unit (201) comprises a plurality of series-connected battery cells, the plurality of series-connected battery cells comprising at least a head battery cell and a tail battery cell, the second voltage detection pin being connected to the positive terminal of the head battery cell, and the second current detection pin being electrically connected to the negative terminal of the tail battery cell.

Images