Battery management system, battery management chip and electronic device

Abstract

The application discloses a battery management system, a battery management chip and electronic equipment. The technical scheme of the embodiment of the application combines two groups of detection ports into one group of detection ports, saves cost and PCB board space, and meanwhile, a protection circuit is added in the battery management system, the number of the protection circuit corresponds to the number of the detection ports, the protection circuit is used for detecting abnormality of the detection ports, and the requirement for peripheral devices of packaging is reduced on the premise of guaranteeing function safety.

Description

Technical Field

[0001] This invention relates to power electronics technology, specifically to power electronics technology, and more specifically to battery management systems, battery management chips, and electronic devices. Background Technology

[0002] With the widespread application of new energy products, electric vehicles have become the mainstream sector of the future automotive market. Electric vehicles rely on battery packs composed of multiple batteries connected in series for power. Therefore, the Battery Management System (BMS), which monitors and manages the battery charge within these packs, plays a crucial role. The BMS monitors, protects, and balances battery voltage, current, and temperature. Addressing the issue of varying charge levels among different batteries within the pack, the BMS utilizes a battery balancing circuit to balance the charge levels of each battery, thereby maximizing the pack's capacity and ensuring maximum energy utilization to extend battery life. To meet the functional safety requirements of the ISO 26262 standard for automotive products, safety failure analysis and fault diagnosis mechanisms must be incorporated into the design. The BMS manages each battery cell using two sets of detection ports. When one detection port malfunctions, such as due to leakage, the two voltage samples taken from the same battery through the two detection ports simultaneously will be inconsistent. This indicates a fault in one detection port and triggers an alarm. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a battery management system and a battery management chip to solve the problems in the prior art.

[0004] According to a first aspect of the present invention, a battery management system is provided. The battery management system includes:

[0005] N+1 detection ports, wherein the second to N+1 detection ports are respectively coupled to the positive potential terminals of the N batteries, and the first detection port is coupled to the negative potential terminal of the first battery; and

[0006] N+1 protection circuits are respectively coupled to the N+1 detection ports;

[0007] The N+1 protection circuits are used to detect the current flowing through the corresponding detection port in order to determine whether the corresponding detection port is abnormal.

[0008] Preferably, the battery management system is integrated into an integrated circuit chip, and the N+1 detection ports are configured as pins of the integrated circuit chip.

[0009] Preferably, the N+1 detection ports are each connected to a corresponding battery via a filter circuit.

[0010] Preferably, the protection circuit includes:

[0011] A detection circuit; connected in series between the corresponding detection port and the functional circuit in the battery management system, used to sample the current flowing through the corresponding detection port and the functional circuit, and to generate a detection voltage; and

[0012] The judgment circuit is used to determine whether the corresponding functional circuit has leakage based on the detected voltage.

[0013] Preferably, the detection voltage is proportional to the current flowing through the detection port and the functional circuit.

[0014] Preferably, the detection circuit includes:

[0015] A resistor, with its two ends connected to a corresponding detection port and a functional circuit respectively, is configured to form a loop with the battery and the functional circuit of the corresponding detection port, wherein the detection voltage is configured as the voltage across the resistor.

[0016] Preferably, the determination circuit is configured as an analog circuit or a digital processing unit.

[0017] Preferably, the determining circuit includes:

[0018] An analog-to-digital converter is used to acquire the voltage across the resistor and convert it into a corresponding digital signal; and

[0019] The logic unit determines whether the voltage drop across the resistor exceeds a safety threshold based on the digital signal.

[0020] Preferably, the determining circuit includes:

[0021] A comparison circuit is used to receive the voltage across the resistor and determine whether the voltage across the resistor exceeds a safety threshold.

[0022] Preferably, the judgment circuit reuses the judgment circuit in the functional circuit to determine whether the voltage drop across the resistor exceeds a safety threshold.

[0023] According to a second aspect of the present invention, a battery management chip is provided. The battery management chip includes:

[0024] N+1 detection pins, wherein the second to N+1 detection pins are respectively coupled to the positive potential terminals of the N batteries, and the first detection pin is coupled to the negative potential terminal of the first battery; and

[0025] N+1 signal processing circuits are coupled to N+1 detection pins respectively, and receive the input signals from the corresponding detection pins to realize the detection of battery voltage and the equalization of battery power.

[0026] Preferably, each signal processing circuit includes a protection circuit for detecting the current flowing through the corresponding detection port to determine whether an abnormality has occurred at the corresponding detection port.

[0027] Preferably, each signal processing circuit includes a voltage detection circuit for detecting the voltage value of each battery cell.

[0028] Preferably, each signal processing circuit includes a battery power equalization circuit for equalizing the power of the corresponding battery so that the power of the N batteries remains consistent.

[0029] Preferably, the first detection pin is coupled to the low-potential end of the battery pack including the N batteries.

[0030] Preferably, the battery management chip includes an N+2 detection pin, which is coupled to the positive potential terminal of the battery pack including the N batteries.

[0031] According to a third aspect of the present invention, an electronic device is provided. The electronic device includes:

[0032] The battery management system as described in any of the first aspects, and

[0033] A battery pack, comprising N batteries connected in series.

[0034] The technical solution of this invention saves cost and PCB board space by merging two sets of detection ports into one set of detection ports. At the same time, the battery management system adds protection circuits, the number of which corresponds to the number of detection ports, and is used to detect port abnormalities. This reduces the demand for peripheral components of the package while ensuring functional safety. Attached Figure Description

[0035] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0036] Figure 1 This is a circuit block diagram of an electronic device according to an embodiment of the present invention;

[0037] Figure 2 This is a circuit block diagram of a proportional battery management system;

[0038] Figure 3 This is a circuit block diagram of the protection circuit according to the first embodiment of the present invention;

[0039] Figure 4This is a circuit block diagram of the protection circuit according to the second embodiment of the present invention;

[0040] Figure 5 This is a circuit block diagram of the protection circuit according to the third embodiment of the present invention;

[0041] Figure 6 This is a circuit block diagram of the protection circuit according to the fourth embodiment of the present invention;

[0042] Figure 7 This is a circuit block diagram of the signal processing circuit according to an embodiment of the present invention. Detailed Implementation

[0043] The present invention is described below based on embodiments, but the invention is not limited to these embodiments. In the detailed description of the invention below, certain specific details are described in detail. Those skilled in the art will fully understand the invention even without these details. To avoid obscuring the essence of the invention, well-known methods, processes, flows, elements, and circuits are not described in detail.

[0044] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0045] Furthermore, it should be understood that in the following description, "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by electrical or electromagnetic connections. When an element or circuit is said to be "connected" to another element or "connected" between two nodes, it can be directly coupled or connected to another element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected" to another element, it means that there are no intermediate elements between them.

[0046] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0047] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0048] Figure 1 This is a circuit block diagram of an electronic device according to an embodiment of the present invention. For example... Figure 1As shown, the electronic device includes a battery management system 100 and a battery pack. The battery management system 100 is used for high-precision voltage acquisition and management of the battery pack. The battery pack includes N batteries d1-dn connected in series. The battery pack can be a lithium battery pack including N lithium batteries. The positive potential terminal of the battery pack is connected to a first terminal P+, and its negative potential terminal is connected to a second terminal P-, where the second terminal P- is a reference ground. The battery pack includes N batteries connected in series between the first terminal P+ and the second terminal P-. The battery management system 100 includes N+1 detection ports and N+1 protection circuits. The second to N+1 detection ports are respectively coupled to the positive potential terminals of the N batteries, and the first detection port is coupled to the negative potential terminal of the first battery. These ports are used to sample the state parameters of the corresponding batteries for battery management, monitoring, and equalization. The state parameters include, but are not limited to, battery voltage, current, and temperature. The N+1 protection circuits are installed inside the battery management system and are connected to the N+1 detection ports C0-Cn respectively to detect whether the corresponding detection port is abnormal. If an abnormality occurs, the battery management system 100 issues an alarm and performs protection operations, such as power-off protection.

[0049] In this application, to ensure more stable battery voltage sampling at each detection port, each detection port is connected to the corresponding battery via a filter circuit. It is understood that the low-pass filter can be constructed from any existing low-pass filter circuit; the simplest circuit is as follows: Figure 1 The diagram shows an RC filter circuit, comprising a resistor Ri and a capacitor Ci connected in series, where 0 ≤ i ≤ n. The input of this RC filter circuit is connected to the corresponding battery, and the output is connected to the corresponding detection port. One end of the capacitor is connected to the output of an adjacent RC filter circuit. For example, for the Nth battery dn, the resistor Rn and capacitor Ci are connected in series, with their common connection point serving as the output of the filter circuit and connected to the detection port Cn. One end of the resistor Rn is connected to the positive potential terminal of the Nth battery dn, and the second end is connected to the detection port Cn. One end of the capacitor Ci is connected to the detection port Cn. The other end is connected to the adjacent detection port C(n-1). For the first detection port C0, the filter circuit comprises a resistor R0 and a capacitor C10 connected in series, with their common connection point serving as the output of the filter circuit and connected to the first detection port C0. One end of the resistor R0 is connected to the negative potential terminal of the first battery, and the other end is connected to the first detection port C0. One end of the capacitor C10 is connected to the detection port C0, and the other end is connected to ground.

[0050] In this embodiment, the battery management system 100 further includes an N+2 detection port BAT, which is coupled to the high-potential terminal of the battery pack, i.e., coupled to the first terminal P+, for providing a power supply voltage to the battery management system 100. Thus, the high-potential terminal of the battery pack can supply power to the battery management system. Further, the N+2 detection port BAT is connected to the high-potential terminal of the battery pack through a filter circuit. This filter circuit includes a resistor R(n+1) and a capacitor C1(n+1) connected in series.

[0051] In this application, the internal functional circuits of the battery management system 100 are connected to corresponding detection ports to perform corresponding functional operations, such as ESD protection circuits and current sampling circuits. When an abnormality occurs in the internal circuit connected to the corresponding detection port, such as leakage, the leakage current will flow through the corresponding detection port. The battery management system 100 can detect the detection port through the corresponding protection circuit to determine whether leakage has occurred. If leakage occurs, the battery management system 100 will issue an alarm. Leakage refers to the phenomenon of current flowing to the ground or other conductors through an abnormal path in insulating materials or equipment. It is prone to occur when equipment insulation is aged, damaged, or damp. In terms of power systems and electrical safety, leakage problems may damage electrical equipment, affecting the normal operation of the entire electrical system. Under high voltage conditions, leakage problems may lead to electric shock accidents, posing a threat to personnel safety.

[0052] In traditional technical solutions, to improve safety, battery management systems typically employ two sets of detection ports. These ports sample the same battery cell twice simultaneously, generating two measurement results. The consistency of these two results indicates whether an anomaly has occurred at the corresponding detection port. Figure 2 As shown. Figure 2 A circuit block diagram of a comparative battery management system is shown. The battery management chip 1 includes two sets of detection ports: the first set includes ports B0-BN, and the second set includes ports C0-CN. The first set of detection ports samples the state parameters of each battery cell via a first sampling path, while the second set of ports samples the state parameters of each battery cell via a second sampling path. The first and second sampling paths are independent of each other. The battery management system can cross-reference the two state parameters of the same battery obtained from the two paths to determine whether an anomaly has occurred at the corresponding detection port. Each sampling path includes a filtering circuit, such as an RC filter circuit.

[0053] When an abnormality occurs in the internal functional circuit connected to the corresponding detection port, such as leakage, the leakage current flows through the corresponding detection port and generates a voltage drop across the resistor in the RC filter circuit. This results in inconsistent voltages sampled from the two ports of the same battery cell, allowing for the determination of whether a port has malfunctioned. This approach, in an effort to improve safety, provides two detection ports for each battery cell. However, since the battery management system is a chip, each port corresponds to a pin on the chip, drastically increasing the number of pins and significantly increasing packaging complexity and cost.

[0054] The battery management system in this application embodiment will... Figure 2 The two sets of detection ports are merged into one, retaining only detection ports C0-Cn and removing detection ports B0-BN and their corresponding peripheral components, thus saving cost and PCB board space. At the same time, the battery management system adds protection circuitry located within the system. The number of these protection circuits corresponds to the number of detection ports, i.e., N protection circuits H1-Hn, minimizing the need for external components while ensuring functional safety.

[0055] In this application, each protection circuit is connected to a corresponding detection port. Each protection circuit includes a detection circuit and a judgment circuit. The detection circuit is connected in series with the corresponding detection port to detect the current flowing through the corresponding detection port. The detection circuit generates a detection voltage, and the judgment circuit receives the detection voltage and determines whether an abnormality, such as leakage, has occurred at the corresponding detection port based on the magnitude of the detection voltage. In this embodiment, protection circuits H1-Hn generate judgment signals POK0-POKn respectively based on the corresponding detection voltage. When at least one judgment signal is valid, the battery management system issues an alarm. Compared with the prior art, the same number of detection ports can manage more batteries. Therefore, the battery management system of this application not only reduces the number of detection ports but also realizes port abnormality detection, thereby reducing packaging difficulty and cost and improving safety.

[0056] Figure 3 This is a circuit block diagram of the protection circuit according to the first embodiment of the present invention. In this embodiment, the battery management system includes N+1 detection ports and N+1 protection circuits. Each protection circuit is connected to a corresponding detection port. Figure 3 Taking the detection port Cn as an example, the protection circuit Hn and the functional circuit 31 are connected to the detection port Cn. The protection circuit Hn is used to detect the corresponding detection port to determine whether leakage has occurred. The functional circuit 31 is connected to the corresponding detection port and is used to perform corresponding functional operations based on the battery's state parameters, such as ESD protection circuitry and current sampling circuitry.

[0057] In this embodiment, the protection circuit Hn includes a detection circuit 301 and a judgment circuit 302. The detection circuit 301 is connected in series between the corresponding detection port and the functional circuit to sample the current flowing through the detection port. Typically, leakage current is caused by the incomplete shut-off of switching devices or capacitive devices in the functional circuit, resulting in a circuit with the battery. Therefore, leakage current can be detected at the connection point between the battery and the functional circuit, i.e., at the detection port. The detection circuit 301 generates a corresponding detection voltage based on the sampled current, and the judgment circuit 302 receives this detection voltage and generates a judgment signal POKn. In this embodiment, the protection circuit can have a separate judgment circuit or reuse the judgment circuit in the functional circuit to save costs. In this embodiment and subsequent embodiments, the judgment circuit can be an analog circuit or a digital circuit, or other electronic unit capable of implementing the above functions; this invention does not limit this. It should be understood that the detection circuit in this embodiment and subsequent embodiments can be implemented using any circuit capable of current detection; this invention does not limit this. Since leakage current requires the battery and related components in the functional circuit to form a loop, the detection circuit needs to maintain the connection between the battery and the functional circuit when detecting leakage current. At the same time, in order to avoid current shunting, the battery and the functional circuit are only connected through the detection circuit.

[0058] Figure 4 This is a circuit block diagram of the protection circuit according to the second embodiment of the present invention. Figure 4 Let's take the detection port Cn as an example. The protection circuit Hn is connected to the detection port Cn to detect the corresponding detection port and determine whether a leakage has occurred.

[0059] The protection circuit includes a detection circuit 40 and a judgment circuit 41. The detection circuit 40 is used to detect the current flowing through the detection port Cn and generate a detection voltage proportional to the current. The judgment circuit 41 receives the detection voltage and determines whether the functional circuit connected to the detection port has a leakage current based on the magnitude of the detection voltage.

[0060] In one embodiment, the detection circuit 40 includes a sampling resistor RSn. The sampling resistor RSn is connected in series to the detection port Cn. If a leakage current occurs in the functional circuit connected to the detection port Cn, the leakage current will generate a voltage drop across the sampling resistor RSn. Therefore, the magnitude of the current flowing through the detection port Cn can be determined based on the voltage across the sampling resistor.

[0061] In this embodiment, the judgment circuit 41 directly samples the voltages VCn and VRn across the sampling resistor RSn to obtain the voltage drop across the sampling resistor RSn, and the magnitude of this voltage drop determines whether an abnormality has occurred in the internal circuit connected to the corresponding detection terminal. In one implementation, when the voltage drop exceeds a safety threshold, the protection circuit generates a valid judgment signal POKn, indicating that leakage has occurred in the functional circuit connected to the detection port.

[0062] Figure 5 This is a circuit block diagram of the protection circuit according to the third embodiment of the present invention. Figure 5 As shown, the judgment circuit of the protection circuit in this embodiment is configured as a comparison circuit 50. The comparison circuit 50 receives the voltages VCn and VRn across the sampling resistor RSn, and generates a judgment signal POKn based on the voltage difference between VCn and VRn. When the voltage difference between VCn and VRn exceeds the safety threshold, it indicates that the corresponding functional circuit has a leakage current, and the judgment signal POKn is a valid signal.

[0063] Figure 6 This is a circuit block diagram of the protection circuit according to the fourth embodiment of the present invention. Figure 6 As shown, the judgment circuit of the protection circuit in this embodiment is configured with an analog-to-digital converter (ADC) 60 and a logic unit 61. The ADC 60 acquires the voltages VCn and VRn across the resistor RSn and converts them into corresponding digital signals. The logic unit 61 determines whether the voltage difference between VCn and VRn exceeds a safety threshold based on the digital signal. If the voltage difference between VCn and VRn exceeds the safety threshold, it indicates that the corresponding functional circuit has a leakage current, and the judgment signal POKn is a valid signal.

[0064] Figure 7 A circuit block diagram of the signal processing circuit according to an embodiment of the present invention. The above embodiment describes the protection circuit in a battery management system. In practical applications, the battery management system is integrated into an integrated circuit chip, with each detection port being a detection pin. This battery management chip includes N+1 signal processing systems, each coupled to a corresponding detection pin, and receives input signals from the corresponding detection pin to achieve battery voltage detection and battery charge equalization. The protection circuit is a functional circuit part of the corresponding signal processing circuit. Figure 7As shown, the signal processing circuit connected to the (N+1)th detection pin Cn is used as an example for explanation. This signal processing circuit includes a protection circuit Hn, a voltage detection circuit 70, and a battery power equalization circuit 71. The function of the protection circuit Hn has been described in detail in the above embodiments and will not be repeated here. The voltage VCn at the detection pin Cn serves as the input signal to the signal processing circuit. The voltage detection circuit 70 receives the voltage VCn and is used to detect the voltage value of each battery cell. In one embodiment, the voltage detection circuit receives the voltage VCn and the voltage at the adjacent detection port, and the difference between the two voltages yields the voltage value of the corresponding battery. In one implementation, the voltage detection circuit 70 is configured as a digital-to-analog converter. The battery power equalization circuit 71 is used to equalize the power of the corresponding batteries to ensure that the power of the N batteries remains consistent. In one embodiment, during charging, when the battery management chip detects that the voltage of one or more cells has reached a higher value first, the corresponding battery power balancing circuit will discharge that battery to consume the excess power. In one implementation, the battery power balancing circuit 72 includes a bypass resistor. When the voltage of a corresponding battery is detected to be too high, the bypass resistor is connected in parallel across the two ends of that battery. In this way, a portion of the charging current will be diverted through the bypass resistor, consuming the excess energy as heat, thereby slowing down the charging speed of these "high-capacity" batteries, waiting for other batteries to catch up, and ultimately achieving voltage synchronization of all batteries.

[0065] The technical solution of this invention combines two sets of detection ports into one set by reducing one set of detection ports, which saves cost and PCB board space. At the same time, the battery management system adds protection circuits, the number of which corresponds to the number of detection ports, and is used to detect port abnormalities. This reduces the demand for peripheral components of the package while ensuring functional safety.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A battery management system for managing N batteries connected in series, the battery management system comprising: There are N+1 detection ports, wherein the second to N+1 detection ports are respectively coupled to the positive potential terminals of the N batteries, and the first detection port is coupled to the negative potential terminal of the first battery. as well as N+1 protection circuits are respectively coupled to the N+1 detection ports; The N+1 protection circuits are used to detect the current flowing through the corresponding detection port in order to determine whether the corresponding detection port is abnormal.

2. The battery management system according to claim 1, characterized in that, The battery management system is integrated into an integrated circuit chip, and the N+1 detection ports are configured with the pins of the integrated circuit chip.

3. The battery management system according to claim 1, characterized in that, The N+1 detection ports are each connected to the corresponding battery through a filter circuit.

4. The battery management system according to claim 1, characterized in that, The protection circuit includes: A detection circuit is connected in series between the corresponding detection port and the functional circuit in the battery management system, for sampling the current flowing through the corresponding detection port and the functional circuit, and generating a detection voltage. as well as The judgment circuit is used to determine whether the corresponding functional circuit has leakage based on the detected voltage.

5. The battery management system according to claim 4, characterized in that, The detection voltage is directly proportional to the current flowing through the detection port and the functional circuit.

6. The battery management system according to claim 4, characterized in that, The detection circuit includes: A resistor, with its two ends connected to a corresponding detection port and a functional circuit respectively, is configured to form a loop with the battery and the functional circuit of the corresponding detection port, wherein the detection voltage is configured as the voltage across the resistor.

7. The battery management system according to claim 4, characterized in that, The determination circuit is configured as an analog circuit or a digital processing unit.

8. The battery management system according to claim 6, characterized in that, The determination circuit includes: An analog-to-digital converter is used to acquire the voltage across the resistor and convert it into a corresponding digital signal; and The logic unit determines whether the voltage drop across the resistor exceeds a safety threshold based on the digital signal.

9. The battery management system according to claim 6, characterized in that, The determination circuit includes: A comparison circuit is used to receive the voltage across the resistor and determine whether the voltage across the resistor exceeds a safety threshold.

10. The battery management system according to claim 8, characterized in that, The judgment circuit reuses the judgment circuit in the functional circuit to determine whether the voltage drop across the resistor exceeds the safety threshold.

11. A battery management chip for managing N batteries connected in series, the battery management chip comprising: There are N+1 detection pins, wherein the second to N+1 detection pins are respectively coupled to the positive potential terminals of the N batteries, and the first detection pin is coupled to the negative potential terminal of the first battery. as well as N+1 signal processing circuits are coupled to N+1 detection pins respectively, and receive the input signals of the corresponding detection pins to realize battery voltage detection and battery power balancing.

12. The battery management chip according to claim 11, characterized in that, Each signal processing circuit includes a protection circuit to detect the current flowing through the corresponding detection port in order to determine whether an abnormality has occurred at the corresponding detection port.

13. The battery management chip according to claim 11, characterized in that, Each signal processing circuit includes a voltage detection circuit for detecting the voltage value of each battery cell.

14. The battery management chip according to claim 11, characterized in that, Each signal processing circuit includes a battery power equalization circuit for equalizing the power of the corresponding batteries so that the power of the N batteries remains consistent.

15. The battery management chip according to claim 11, characterized in that, The first detection pin is coupled to the low potential end of the battery pack, which includes the N batteries.

16. The battery management chip according to claim 11, characterized in that, The battery management chip includes an N+2 detection pin, which is coupled to the positive potential terminal of the battery pack comprising the N batteries.

17. An electronic device comprising: The battery management system as described in any one of claims 1-10, and A battery pack, comprising N batteries connected in series.

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