TW202021230A - Battery management system and method thereof capable of preventing one of the batteries in the battery pack from turning into reverse charging - Google Patents

Abstract

The present invention provides a battery management system and a method thereof, with which the batteries of a battery pack in different levels can be managed individually, so as to avoid overall damage or improper consumption of the batteries, and to prevent one of the batteries in the battery pack from turning into reverse charging after being completely discharged. The battery management system comprises a battery module, a reference resistance module, a control circuit, and a display control module.

Description

Battery management system and method

The present invention relates to a management system and method, and particularly to a battery management system and method.

Generally speaking, the safety protection items provided by the existing battery management system include charging overvoltage protection, charging overcurrent protection, discharge overheating protection, charging overheating protection and charging time protection, etc. When the battery management system performs charging overvoltage protection, the battery management system will initiate a protection mechanism when the battery voltage exceeds a voltage threshold during charging, such as cutting off the battery's charge switch and when the voltage drops below this voltage threshold Remove the protection mechanism.

With the rapid development of electronic technology today, high-voltage series battery packs have been widely used in electric vehicles, hybrid vehicles, and industrial backup batteries. Among them, lithium batteries are more widely used today. Regardless of the state of charge or discharge, existing lithium battery management systems measure battery voltage by measuring the voltage between the positive and negative terminals of the battery. It is the sum of the voltage corresponding to the battery's electromotive force plus the voltage drop generated by the internal resistance of the battery when the current flows. Therefore, the voltage measured between the positive and negative terminals of the battery will vary with the current used during the measurement Affected by the size, no matter the current used by the energy storage device or the vehicle is changing at any time, the current management system measures the voltage of each battery in a sequential manner, not at the same time to measure the voltage at each point, especially when the lithium iron battery is in use , The voltage from full load to use 90% relative to the voltage reduction is less than 10%, and the minimum difference of the change in the corresponding current is often more than 10 times, so this current change reflects the voltage drop on the internal resistance of the battery Change reaches electricity The change of the electromotive force caused by the difference in the battery power is more than several times, which results in the current battery monitoring cannot correctly detect the battery condition under such a battery power change.

In addition, the existing battery management system will start the charge balance function when one (or several) batteries are fully charged during the charging or discharging process, so as to wait for other batteries to be fully charged before turning off the power. Completely full battery demand, must consume a lot of energy, the battery management of low-power battery packs, the impact is lower, such as laptop or notebook computer battery management system (the power does not change much when the power is about 100 watts), However, the power of batteries used in energy storage devices or vehicles exceeds thousands of watts. To fully meet the battery requirements, the battery management system requires a very high power value, so the cost of the battery management system is higher and the volume will increase significantly. , And it will cause a lot of heat, so the current products on the market are more difficult to meet and meet the above requirements for larger power. In addition, during use, as long as the battery with the smaller storage capacity in the battery pack is discharged, the entire battery pack cannot Continue to use it, so a lot of energy is wasted when charging so that the overcharged battery can not be used.

In addition, the high-voltage batteries used in electric vehicles or hybrid vehicles are battery packs formed by connecting multiple batteries in series, and high voltages are obtained by connecting the batteries in series. It will cause the battery management system to need a large area of circuits to set a plurality of balancing modules or monitoring modules to monitor each level of the battery. Thus, the conventional battery management system will increase the circuit area and increase the circuit complexity.

In this way, the circuit architecture of the existing battery management system is not easy to accurately determine the state of excessive charge and discharge of the battery pack, and the circuit is complicated. When the balancing function is activated, a large amount of energy is consumed and high heat is generated, so a large heat dissipation device is required, otherwise the failure rate will be very high High, resulting in higher cost of the existing battery management system and wasting more energy in the process of charging and discharging. In addition, in the case of inaccurate measurement of the battery state, the battery is kept at the edge of higher voltage charging or overdischarging. This will shorten the battery life.

In view of the above problems, the present invention provides a battery management system and method thereof, which provides a battery pack with a plurality of Wheatstone bridges connected in parallel to a single monitoring circuit, which can monitor each battery of the battery pack separately and reduce the monitoring circuit load , When any battery will reach saturation That is, reduce the charging current to avoid over-saturated charging. When the set amount of charging power is reached, the charging is stopped immediately, and the over-saturated charging is avoided without balancing the charging.

An object of the present invention is to provide a battery management system, in which each battery in a battery pack is independently monitored by a Wheatstone bridge and according to the monitoring results, when any battery is saturated, the charging current is reduced to avoid oversaturation Charging, stop charging immediately when the charging power is set, avoid over-saturated charging without balancing charging, and damage battery life.

In order to achieve the above object, an embodiment of the present invention discloses a battery management system, which includes at least one battery module, at least one reference resistor module, at least one control circuit, and a display control device. The battery module is divided into a first battery pack and a second battery pack according to a first reference point of the control circuit, the first battery pack includes a plurality of first batteries, and the second battery pack includes a plurality of second batteries, And a first reference point of the control circuit is connected between the first battery group and the second battery group, and the reference resistance module is connected to one end of the first battery group and the second battery group, and the reference resistance module is connected to the control The second reference point of one of the circuits is connected, whereby the first battery pack, the second battery pack and the reference resistor module form a plurality of Wheatstone bridges, so the Wheatstone bridges are connected in parallel to the control circuit The control circuit is further connected to the display control device. The display control device controls the first batteries and the second batteries according to the electrical detection results of the first batteries and the second batteries. By measuring the battery packs through the Wheatstone bridges, the voltage drops generated by different currents on the internal resistance of the battery packs will cancel each other out, and will not interfere with the measurement results. The battery status of the battery packs is used to manage the charging and discharging of the battery, and the charging is turned off when the battery is fully charged to avoid oversaturated charging of the battery.

The present invention provides an embodiment in which the first batteries and the second batteries are connected in series, and the control circuit connects the first batteries and the second batteries in parallel.

The present invention provides an embodiment, which further includes a current measuring unit connected in series to the at least one battery module to measure the current of the at least one battery module.

The present invention provides an embodiment, which further includes a current measuring unit connected in series to the at least one battery module to measure the current of the at least one battery module; and a charge-discharge switch electrically connected to at least one control The circuit and the display control device control the first batteries and the first batteries through the control circuit according to the current of the at least one battery module and the electrical properties of the first batteries and the second batteries 2. Charging and discharging of the battery.

The invention provides an embodiment, wherein the control circuit is a single chip (MCU) or an application integrated circuit (APIC).

The present invention provides an embodiment, wherein the electrical properties of the first batteries and the second batteries are voltages or currents of the first batteries and the second batteries.

The present invention provides an embodiment, wherein the reference resistor module includes a first reference resistor and a second reference resistor, one end of the first reference resistor and the second reference resistor is connected to the second reference point, the first reference The other ends of the resistor and the second reference resistor are respectively connected to the first battery pack and the second battery pack.

Another embodiment of the present invention discloses a battery management method. The steps include: a control circuit detects the electrical property of a battery module via a plurality of Wheatstone bridges; and a method based on the electrical property of the battery module The detection result adjusts the battery balance of the battery module, wherein the battery module includes a first battery pack and a second battery pack, the first battery pack includes a plurality of first batteries, and the second battery pack includes a plurality of A second battery, a first reference point of the control circuit is connected between the first battery pack and the second battery pack, the Wheatstone bridges connect the first batteries and the second batteries in parallel To the control circuit, the control circuit controls the charging and discharging of the first batteries and the second batteries according to the Wheatstone bridges, and controls at least the first batteries and the second batteries One will turn off charging after the battery is saturated. By measuring the battery packs through the Wheatstone bridges, the voltage drops generated by different currents on the internal resistance of the battery packs will cancel each other out, and will not interfere with the measurement results. The battery status of the battery packs is used to manage the charging and discharging of the battery to avoid over-saturated charging.

The present invention provides another embodiment. The steps further include measuring the current of the battery module; and controlling the charging and discharging of the battery module according to the current of the battery module.

The present invention provides another embodiment, wherein the electrical property of the battery module is the voltage or current of the battery module.

10‧‧‧ battery management system

12‧‧‧Battery module

122‧‧‧The first battery pack

122a‧‧‧The first battery

122r‧‧‧First internal resistance

124‧‧‧The second battery pack

124a‧‧‧second battery

124r‧‧‧Second internal resistance

14‧‧‧Reference resistance module

142‧‧‧ First resistance

144‧‧‧Second resistance

16‧‧‧Control circuit

Ref1‧‧‧First reference point

Ref2‧‧‧second reference point

18‧‧‧Display control device

20‧‧‧Current measurement unit

22‧‧‧Charge and discharge switch

30‧‧‧ battery management system

32‧‧‧Battery module

322‧‧‧The first battery pack

322a‧‧‧The first battery

322r‧‧‧First internal resistance

324‧‧‧The second battery pack

324a‧‧‧second battery

324r‧‧‧Second internal resistance

34‧‧‧Reference resistance module

342‧‧‧ First resistance

344‧‧‧Second resistance

36‧‧‧Control circuit

38‧‧‧Display control device

40‧‧‧Current measurement unit

42‧‧‧Charge and discharge control unit

cell1‧‧‧The first energy storage unit

cell2‧‧‧Second energy storage unit

The first figure: it is a system schematic diagram of an embodiment of the present invention; the second figure: it is a flowchart of an embodiment of the present invention; and the third figure: it is a system schematic diagram of another embodiment of the present invention.

In order for your reviewing committee to have a better understanding and understanding of the features of the present invention and the achieved effects, the preferred embodiments and detailed descriptions are accompanied by the following explanations:

Hereinafter, the present invention will be described in detail by illustrating various embodiments of the present invention through the drawings. However, the concept of the present invention may be embodied in many different forms, and should not be interpreted as being limited to the exemplary embodiments set forth herein.

In order to break the traditional battery module, each battery is provided with a control circuit for detecting the battery's electrical property. Therefore, a method for battery management is provided. The user can switch the receivers through a Wheatstone bridge with a single control circuit. Detected battery.

First, please refer to the first figure, which is a schematic diagram of a system according to an embodiment of the present invention. As shown, the battery management system 10 of the present invention includes a battery module 12, a reference resistor module 14, a control circuit 16 and a display control device 18. The battery module 12 includes a first battery group 122 and a second battery group 124. The first battery group 122 includes a plurality of first energy storage units cell1, and the first energy storage units cell1 each include a first battery 122a and a first internal resistance 122r, the second battery pack 124 includes a plurality of second energy storage units cell2, and the second energy storage units cell2 include a second battery 124a and a second internal resistance 124r, respectively. The reference resistor module 14 includes a first resistor 142 and a second resistor 144. The control circuit 16 is provided with a first reference point (V0' pin) Ref1 and a second reference point (V0 pin) R2. The first reference point Ref1 is connected to the first battery pack 122 Between the second battery pack 124, the second reference point Ref2 is connected to the reference resistor module 14, further, the second reference point Ref2 is connected between the first resistor 142 and the second resistor 144.

The display control device 18 is electrically connected to the control circuit 16 to show that the control circuit 16 detects the electrical properties of the first batteries 122a and the second batteries 124a and is based on the first batteries 122a and the second batteries The electrical properties of the battery 124a set the charging and discharging of at least one of the first batteries 122a and the second batteries 124a. In addition, the control circuit 16 is connected in parallel to the first batteries 122a and the second batteries 124a, and thus according to the first reference point Ref1 and the second reference point Ref2, and the first batteries 122a and the second batteries The internal resistance of the battery 124a (the first internal resistance 122r and the second internal resistance 124r) matches the first resistance 142 and the second resistance 144, thereby forming a plurality of Wheatstone bridges. By measuring the battery packs through the Wheatstone bridges, the voltage drops generated by different currents on the internal resistance of the battery packs will cancel each other out, and will not interfere with the measurement results. Battery status of several battery packs

The battery management system 10 further includes a current measurement unit 20 and a charge-discharge switch 22. The current measurement unit 20 is connected in series to the battery module 12, that is, the current measurement unit 20 is connected in series to the first batteries 122a and the The second batteries 124a, the first internal resistances 122r and the second internal resistances 124r are used to obtain the current of the battery module 12, wherein the current measuring unit 20 may be a Coulomb meter, which is measured by the current The unit 20 monitors the degree of charge and discharge of the first batteries 122a and the second batteries 124a of the battery pack 12. The charge and discharge switch 22 is connected to the control circuit 16 and the display control device 18 according to the current of the battery module 12, the setting of the display control device 18 and the first energy storage units cell1 and the second energy storage units The electrical property of cell 2 is used to control the bypass of the first batteries 122a and the second batteries 124a through the control circuit 16, for example: generating a charge and discharge signal to the control circuit 16 to control the first When one of the batteries 122a and the second batteries 124a has a full or near full storage capacity (the storage capacity exceeds 90%), the battery with a storage capacity exceeding 90% is bypassed to avoid battery oversaturation.

The control circuit 16 of this embodiment is exemplified by a single chip (MCU). In addition, the control circuit 16 can also be an application integrated circuit (APIC); the first batteries 122a and the The electrical property of the second battery 124a is the voltage or current of the first batteries 122a and the second batteries 124a. The first batteries 122a and the second batteries 124a are In this embodiment, four batteries are connected in series, which provides a voltage of 12 volts. In addition, the first batteries 122a and the second batteries 124a can be connected in series with eight batteries in this embodiment. To provide 24 volts. In addition, the first batteries 122a are respectively electrically connected to a first internal resistance 122r, and the first batteries 124a are respectively connected to the second internal resistance 124r.

First, please refer to the second figure, which is a flowchart of an embodiment of the present invention. As shown in the figure, the battery management method of the present invention includes the following steps: Step S1: a control circuit detects the electrical properties of a battery module through a plurality of Wheatstone bridges; and Step S3: according to the battery module An electrical detection result adjusts the power balance of the first batteries and the second batteries.

The flow of one embodiment of the present invention will be described below, please refer to the first and second figures.

In step S1, and referring to the first figure together, since the battery module 12 includes a first battery group 122 and a second battery group 124, the first battery group 122 includes a plurality of first energy storage units cell1, the The first energy storage units cell1 respectively include a first battery 122a and a first internal resistance 122r, the second battery pack 124 includes a plurality of second energy storage units cell2, and the second energy storage units cell1 respectively include A second battery 124a and a second internal resistance 124r. The reference resistor module 14 includes a first resistor 142 and a second resistor 144, and the control circuit 16 is connected in parallel to the first batteries 122a and the second batteries 124a, so according to the first reference point Ref1 and the second Reference point Ref2, and the internal resistances of the first batteries 122a and the second batteries 124a (the first internal resistance 122r and the second internal resistance 124r) match the first resistance 142 and the second resistance 144, thus forming a plurality of Wheatstone bridge. Therefore, the control circuit 16 measures the electrical properties of the first batteries 122a and the second batteries 124a through the Wheatstone bridges, that is, measures the first batteries 122a and the first batteries respectively. The two batteries 124a and their internal resistances (the first internal resistance 122r and the second internal resistance 124r) are combined with the voltage and current measured by the first resistor 142 and the second resistor 144.

In step S3, and referring to the first figure together, the control circuit transmits the electrical property detection result in step S1 to the display control device, and sets the control circuit 16 and the charge and discharge switch 22, and displays the electrical property in step S1 Detection result, for example: setting the power of the charge and discharge switch 22 in step S1 The result of the sex detection is that one of the first batteries 122a or a second battery 124a has a storage capacity of less than 10% and is charged immediately, or one of the first batteries 122a or a second battery 124a has a storage capacity of more than 90% and the other The first battery 122a or the second battery 124a is still below 70%, thereby immediately bypassing the battery that has 90% of the stored electricity. Through the control of charging and discharging as described above, the storage capacity of one of the first batteries 122a or the second battery 124a is prevented from being overloaded.

Please refer to the third diagram for a system schematic diagram of another embodiment of the present invention. As shown, the battery management system 30 of the present invention includes a plurality of battery modules 32, a plurality of reference resistance modules 34, a plurality of control circuits 36 and a display control device 38, a current detection unit 40, and a current amount测单元42。 The test unit 42. The connection relationships of the battery modules 32, the reference resistor modules 34, and the control circuits 36 have been described in the previous embodiment, so they will not be repeated in this embodiment.

In addition to setting the control circuit 36 individually, the display control device 38 further sets the charging between the battery modules 32 and bypasses the battery when the battery is in a saturated state. Among the battery modules 32, each battery module 32 has a first battery pack 322 and a second battery pack 324 respectively. The first battery pack 322 has a plurality of first energy storage units cell1, and the An energy storage unit cell1 has a first battery 322a and a first internal resistance 322r, respectively, and the second battery pack 324 has a plurality of second energy storage units cell2, and the second energy storage units cell2 each have a second battery 324a and a second internal resistance 324r. The control circuits 36 can control the battery modules 32 respectively. The control circuits 36 can also be controlled by a single control circuit 36. The control circuits 36 can monitor each first energy storage. The electrical properties of the cell cell1 and each second energy storage unit cell2.

Since the above embodiment does not use a balanced system, the energy consumption of the overall system is greatly reduced, and the cost of building the system is also greatly reduced, and it can be applied to high-power battery applications, such as energy storage equipment, vehicle batteries group. Furthermore, in the above embodiments, the control circuit can be made through a low-voltage semiconductor circuit, and can be applied to high-voltage applications through series connection, thereby reducing high-voltage semiconductor circuits, thereby reducing costs, and providing higher stability and detection. Battery management system with higher sensitivity and higher efficiency.

In summary, the present invention is a battery management system and method thereof, which measures the state of each battery through the Wheatstone bridge method, so that the voltage drop generated by different currents on the internal resistance of the battery It will cancel each other, and it is not easy to interfere with the measurement results to accurately measure the battery status. In addition, the current measurement unit monitors the battery charge and discharge level, and monitors the battery status through the Wheatstone bridge to manage the battery pack, so there is no need to Build a balanced system to reduce system cost and save energy consumed by the system. In addition, the control circuit of the present invention can use a lower voltage module, and in the application of high voltage, it can be used as long as the low voltage module is connected in series, and the use of high voltage semiconductors is reduced to reduce the application cost and improve efficiency and stability And improve monitoring sensitivity. .

However, the above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. All changes and modifications based on the shape, structure, features and spirit described in the patent application scope of the present invention , Should be included in the scope of the patent application of the present invention.

The present invention is based on those who are novel, progressive and available for industrial use, and should meet the patent application requirements stipulated by the Patent Law of our country. Undoubtedly, an application for an invention patent is filed in accordance with the law. prayer.

10‧‧‧ battery management system

12‧‧‧Battery module

122‧‧‧The first battery pack

122a‧‧‧The first battery

122r‧‧‧First internal resistance

124‧‧‧The second battery pack

124a‧‧‧second battery

124r‧‧‧Second internal resistance

14‧‧‧Reference resistance module

142‧‧‧ First resistance

144‧‧‧Second resistance

16‧‧‧Control circuit

cell1‧‧‧The first energy storage unit

cell2‧‧‧Second energy storage unit

Ref1‧‧‧First reference point

Ref2‧‧‧second reference point

18‧‧‧Display control device

20‧‧‧Current measurement unit

22‧‧‧Charge and discharge switch

Claims (10)

A battery management system, the steps of which include: at least one battery module, which includes a first battery pack and a second battery pack, the first battery pack includes a plurality of first batteries, and the second battery pack includes a plurality of first batteries Two batteries; at least one reference resistor module, respectively connected to one end of the first battery group and the second battery group; at least one control circuit, a first reference point of which is connected to the first battery group and the second battery Between groups and between the first batteries and the second batteries, a second reference point of the control circuit is connected to the reference resistor module; and a display control device is electrically connected to the The control circuit displays that the control circuit detects the electrical properties of the first batteries and the second batteries and sets the first batteries and the second batteries according to the electrical properties of the first batteries and the second batteries Charging and discharging of at least one of the second batteries; wherein the internal resistances of the first batteries and the second batteries and the at least one reference resistor module form a plurality of Wheatstone bridges to be electrically connected To the at least one control circuit, the at least one control circuit detects the electrical properties of the first batteries and the second batteries according to the Wheatstone bridges, respectively. The battery management system as described in item 1 of the patent application scope, wherein the first batteries and the second batteries are connected in series, and the control circuit connects the first batteries and the second batteries in parallel. The battery management system described in item 1 of the patent application scope further includes: a current measuring unit connected in series to the at least one battery module to measure the current of the at least one battery module. The battery management system as described in item 1 of the patent application scope further includes: a current measurement unit connected in series with the at least one battery module to measure the current of the at least one battery module; and A charge-discharge switch, which is electrically connected to at least one control circuit and the display control device, based on the current of the at least one battery module and the electrical properties of the first batteries and the second batteries, through the control The circuit controls the charging and discharging of the first batteries and the second batteries. The battery management system as described in item 1 of the patent application scope, wherein the control circuit is a single chip (MCU) or an application integrated circuit (APIC). The battery management system as described in item 1 of the patent scope, wherein the electrical properties of the first batteries and the second batteries are the voltages or currents of the first batteries and the second batteries. The battery management system as described in item 1 of the patent application range, wherein the reference resistor module includes a first reference resistor and a second reference resistor, and one end of the first reference resistor and the second reference resistor is connected to the second At a reference point, the other ends of the first reference resistor and the second reference resistor are respectively connected to the first battery pack and the second battery pack. A battery management method, the steps of which include: a control circuit detects a battery module via a plurality of Wheatstone bridges, the battery module includes a first battery pack and a second battery pack, the first battery pack includes a plurality of A first battery, the second battery pack includes a plurality of second batteries, a first reference point of the control circuit is connected between the first battery pack and the second battery pack, the Wheatstone bridges are connected in parallel The first batteries and the second batteries to the control circuit; and controlling the bypass of at least one of the first batteries and the second batteries according to a detection result of the battery module; wherein, The control circuit controls the charging and discharging of the first batteries and the second batteries according to the Wheatstone bridges. According to the battery management method described in item 8 of the patent application scope, the steps further include: measuring the current of the battery module; and controlling the charging and discharging of the battery module according to the current of the battery module. The battery management method as described in item 8 of the patent application scope, wherein the battery module The electrical property is the voltage or current of the battery module.

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