Voltage measurement device and method
阅读说明:本技术 电压测量装置和方法 (Voltage measurement device and method ) 是由 金东玄 于 2018-11-19 设计创作,主要内容包括:提供了电压测量装置和方法。根据本发明的电压测量装置用于测量包括在电池模块中的多个二次电池中的每一个的两端的电压。电池模块还包括汇流条。汇流条电连接在多个二次电池中的一个的负极端子和电池模块的负极端子之间。该电压测量装置包括多个电压输入端子,所述多个电压输入端子电连接到多个二次电池中的每一个的两端,并且用于接收多个二次电池中的每一个的两端的电压。多个电压输入端子中的一个是与第一参考接地电分离的参考电压输入端子。参考电压输入端子电连接到第二参考接地,第二参考接地连接到汇流条的一端并且接收施加到第二参考接地的电压。(Voltage measurement devices and methods are provided. The voltage measuring device according to the present invention is used to measure the voltage across each of a plurality of secondary batteries included in a battery module. The battery module further includes a bus bar. The bus bar is electrically connected between a negative terminal of one of the plurality of secondary batteries and a negative terminal of the battery module. The voltage measuring device includes a plurality of voltage input terminals electrically connected to both ends of each of the plurality of secondary batteries and for receiving voltages of both ends of each of the plurality of secondary batteries. One of the plurality of voltage input terminals is a reference voltage input terminal electrically separated from the first reference ground. The reference voltage input terminal is electrically connected to a second reference ground that is connected to one end of the bus bar and receives a voltage applied to the second reference ground.)
1. An apparatus connected to a battery module including a positive terminal, a negative terminal, a bus bar, and a plurality of secondary batteries connected in series in a sequential order between the positive terminal and the negative terminal, the apparatus for measuring a voltage of each of the plurality of secondary batteries, the apparatus comprising:
a measurement unit including a plurality of voltage input terminals electrically connected to both ends of each of the plurality of secondary batteries to receive voltages of both ends of each of the plurality of secondary batteries; and a first ground terminal electrically connected to a first reference ground electrically connected to the negative terminal of the battery module; and
a control unit configured to receive a voltage across each of the plurality of secondary batteries from the measurement unit; and the control unit comprises a second ground terminal electrically connected to the first reference ground,
wherein one of the plurality of voltage input terminals is a reference voltage input terminal electrically connected to a second ground reference connected to one end of the bus bar to receive a voltage applied to the second ground reference, and
the reference voltage input terminal is electrically separated from the first reference ground such that the reference voltage input terminal and the first reference ground have different reference potentials.
2. The device according to claim 1, wherein the control unit is further configured to calculate the direct-current internal resistance of at least one of the plurality of secondary batteries using a voltage across at least one of the plurality of secondary batteries.
3. The apparatus of claim 1, wherein the reference voltage input terminal is electrically connected to the second reference ground through a first wiring, and
the first reference ground is electrically connected to the negative terminal of the battery module through a second wiring electrically separated from the first wiring.
4. The apparatus according to claim 3, wherein the reference voltage input terminal takes a voltage applied to the second reference ground connected to one end of the bus bar as a reference potential of the reference voltage input terminal, and
the first reference ground takes a voltage applied to the negative terminal of the battery module connected to the other end of the bus bar as a reference potential of the first reference ground.
5. The apparatus of claim 3, wherein the first and second wires are electrically separated from each other on a printed circuit board.
6. The apparatus of claim 5, wherein the first and second wires are configured to prevent a charge/discharge current from flowing.
7. An apparatus connected to a battery module including a positive terminal, a negative terminal, a bus bar, and a plurality of secondary batteries connected in series in a sequential order between the positive terminal and the negative terminal, the apparatus for measuring a voltage of each of the plurality of secondary batteries, the apparatus comprising:
a measurement unit comprising: a plurality of voltage input terminals electrically connected to both ends of each of the plurality of secondary batteries to receive a voltage across both ends of each of the plurality of secondary batteries; and a plurality of current measurement terminals connected to both ends of a current sensor connected to the battery module to receive voltages of both ends of the current sensor; and
a control unit configured to receive a voltage across each of the plurality of secondary batteries and a voltage across the current sensor measured from the measuring unit at the same measurement time, calculate a voltage value of each of the plurality of secondary batteries based on the voltage across each of the plurality of secondary batteries, and calculate a current value using the voltage across the current sensor,
wherein one of the plurality of voltage input terminals is a reference voltage input terminal electrically separated from a first reference ground such that the reference voltage input terminal and the first reference ground have different reference potentials, and
the reference voltage input terminal is electrically connected to a second reference ground connected to one end of the bus bar to receive a voltage applied to the second reference ground.
8. A battery pack comprising the device of any one of claims 1-7.
9. A method of measuring a voltage of each of a plurality of secondary batteries using a device connected to a battery module, the battery module including a positive terminal, a negative terminal, a bus bar, and the plurality of secondary batteries connected in series in sequential order between the positive terminal and the negative terminal, the method comprising the steps of:
receiving a voltage across each of the plurality of secondary batteries using a voltage applied to a reference voltage input terminal electrically connected to a second reference ground electrically separated from a first reference ground as a second reference potential, wherein the first reference ground has a first reference potential and is electrically connected to the negative terminal of the battery module; and
calculating a direct current internal resistance of at least one of the plurality of secondary batteries using at least one of voltages across the plurality of secondary batteries.
Technical Field
The present disclosure relates to an apparatus and method for measuring voltage, and more particularly, to an apparatus and method for measuring voltage of a secondary battery included in a battery module.
The present application claims priority from korean patent application No. 10-2017-.
Background
Recently, the demand for portable electronic products such as laptop computers, video cameras, and mobile phones has been sharply increased, and with the widespread development of secondary batteries for energy storage, robots, and satellites, many studies are being conducted on high-performance secondary batteries that can be repeatedly recharged.
Currently, commercially available secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, lithium secondary batteries, and the like, among which the lithium secondary batteries have little or no memory effect, and thus the lithium secondary batteries are more spotlighted than the nickel-based secondary batteries due to their advantages of free charge and discharge, very low self-discharge rate, and high energy density.
Battery packs are used in various fields, and in many cases, they are used in applications requiring large capacity, such as an electrically driven vehicle or a smart grid system. In order to increase the capacity of the battery pack, there may be a method of increasing the capacity of the secondary battery or the battery cell itself, but in this case, the capacity increasing effect is not so large, and there is a physical limitation in the size expansion of the secondary battery. Therefore, a battery pack including a plurality of battery modules connected in series and parallel is generally widely used.
In many cases, the battery pack includes a Battery Management System (BMS) to manage the battery modules. In addition, the BMS monitors the temperature, voltage, and current of the battery modules, and controls a balancing operation, a cooling operation, a charging operation, or a discharging operation of the battery pack based on the monitored states of the battery modules. For example, when a battery module includes a plurality of secondary batteries, the BMS measures voltages of the plurality of secondary batteries, and estimates a Direct Current Internal Resistance (DCIR), a state of charge (SOC), and a state of health (SOH) of each secondary battery based on the measured voltages of the secondary batteries.
In the conventional voltage measurement technology, the voltage of each secondary battery is measured using the operating potential of the components within the BMS, which is equal to the reference potential of the voltage measurement, for the convenience of measurement.
However, in the case of the conventional voltage measuring device, the charge/discharge current flowing in the charge/discharge path provided in the battery pack flows in the internal components of the BMS, not in the charge/discharge path, which results in a measured voltage error of the secondary battery and errors in the estimated DCIR, SOC, and SOH.
Disclosure of Invention
Technical problem
The present disclosure is directed to solving the above-mentioned problems, and therefore, the present disclosure is directed to providing an apparatus and method for voltage measurement with improved reliability by reducing errors in voltage measurement in measuring the voltage of each secondary battery provided in a battery module.
These and other objects and advantages of the present disclosure will be understood by the following description, and will be apparent from the embodiments of the present disclosure. Further, it will be readily understood that the objects and advantages of the present disclosure may be realized by means set forth in the appended claims and combinations thereof.
Technical scheme
In order to achieve the above object, an apparatus according to one embodiment of the present disclosure for measuring a voltage of each of a plurality of secondary batteries is connected to a battery module including a positive terminal, a negative terminal, the plurality of secondary batteries connected in series in a sequential order between the positive terminal and the negative terminal, and a bus bar. The apparatus includes a measurement unit including a plurality of voltage input terminals electrically connected to both ends of each of the plurality of secondary batteries to receive voltages of both ends of each of the plurality of secondary batteries; a first ground terminal electrically connected to a first reference ground electrically connected to a negative terminal of the battery module; and a control unit configured to receive a voltage across each of the plurality of secondary batteries from the measurement unit, and including a second ground terminal electrically connected to the first reference ground. One of the plurality of voltage input terminals is a reference voltage input terminal electrically connected to a second reference ground connected to one end of the bus bar to receive a voltage applied to the second reference ground. The reference voltage input terminal is electrically separated from the first reference ground such that the reference voltage input terminal and the first reference ground have different reference potentials.
The control unit may be further configured to calculate the direct current internal resistance of at least one of the plurality of secondary batteries using voltages across the at least one of the plurality of secondary batteries.
The reference voltage input terminal is electrically connected to the second reference ground through the first wiring. The first reference ground may be electrically connected to the negative terminal of the battery module through a second wiring electrically separated from the first wiring.
The reference voltage input terminal may take a voltage applied to a second reference ground connected to one end of the bus bar as a reference potential of the reference voltage input terminal. The first reference ground may have a voltage applied to a negative terminal of the battery module connected to the other end of the bus bar as a reference potential of the first reference ground.
The first wiring and the second wiring may be electrically separated from each other on the printed circuit board.
The first wiring and the second wiring may be configured to prevent a charge/discharge current from flowing.
An apparatus according to another aspect of the present disclosure is connected to a battery module including a positive terminal, a negative terminal, a plurality of secondary batteries connected in series in a sequential order between the positive terminal and the negative terminal, and a bus bar, for measuring a voltage of each of the plurality of secondary batteries. The apparatus includes a measurement unit including a plurality of voltage input terminals electrically connected to both ends of each of the plurality of secondary batteries to receive voltages of both ends of each of the plurality of secondary batteries; and a plurality of current measurement terminals connected to both ends of a current sensor connected to the battery module to receive voltages of both ends of the current sensor; and a control unit configured to receive the voltage across each of the plurality of secondary batteries and the voltage across the current sensor simultaneously measured from the measuring unit, calculate a voltage value of each of the plurality of secondary batteries based on the voltage across each of the plurality of secondary batteries, and calculate a current value using the voltage across the current sensor. One of the plurality of voltage input terminals is a reference voltage input terminal electrically separated from the first reference ground such that the reference voltage input terminal and the first reference ground have different reference potentials. The reference voltage input terminal is electrically connected to a second reference ground connected to one end of the bus bar to receive a voltage applied to the second reference ground.
A battery pack according to still another aspect of the present disclosure includes a device that measures voltage.
A method according to yet another aspect of the present disclosure measures a voltage of each of a plurality of secondary batteries using a device connected to a battery module including a positive terminal, a negative terminal, a plurality of secondary batteries connected in series between the positive terminal and the negative terminal in a sequential order, and a bus bar. The method includes receiving a voltage across each of the plurality of secondary batteries using a voltage applied to a reference voltage input terminal electrically connected to a second reference ground electrically separated from the first reference ground as a second reference potential. The first reference ground has a first reference potential and is electrically connected to the negative terminal of the battery module. The method further includes calculating a direct current internal resistance of at least one of the plurality of secondary batteries using at least one of voltages on both ends of the plurality of secondary batteries.
Advantageous effects
According to the present disclosure, the reference potential for voltage measurement and the reference potential for operation of the voltage measurement device are electrically separated from each other, and they have different potentials. In addition, during the voltage measurement, the charge/discharge current flowing through the charge/discharge path does not flow in the voltage measurement device. Therefore, the reliability of voltage measurement in the voltage measurement process can be improved.
The present disclosure may have various other effects, and these and other effects may be understood by the following description, and will be apparent from the embodiments of the present disclosure.
Drawings
The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the detailed description below of the disclosure, serve to provide a further understanding of the technical aspects of the disclosure, and therefore the disclosure should not be construed as being limited to the accompanying drawings.
Fig. 1 is a schematic view illustrating connections between components of a device for measuring voltage and a battery pack according to one embodiment of the present disclosure.
Fig. 2 is a schematic view illustrating a connection between a BMS printed circuit board including a device measuring voltage and a charge/discharge path of a battery pack according to one embodiment of the present disclosure.
Fig. 3 is a table for reference in describing an operation of the apparatus for measuring voltage calculating the internal resistance of the secondary battery according to one embodiment of the present disclosure.
Fig. 4 is a schematic diagram illustrating connections between components of a device for measuring voltage and a battery pack according to a comparative example of the present disclosure.
Fig. 5 is a diagram for reference in describing a current path formed by the apparatus for measuring voltage according to the comparative example of the present disclosure.
Fig. 6 is a table for reference in describing an operation of the voltage measuring apparatus according to the comparative example of the present disclosure to calculate the internal resistance of the secondary battery.
Fig. 7 is a schematic flow chart diagram illustrating a method of measuring voltage according to one embodiment of the present disclosure.
Detailed Description
Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms or words used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation.
Therefore, the embodiments described herein and the illustrations shown in the drawings are only the most preferred embodiments of the present disclosure and are not intended to fully describe the technical aspects of the present disclosure, and therefore it should be understood that various other equivalents and modifications may be made thereto at the time of filing this application.
In addition, in describing the present disclosure, a detailed description of related known elements or functions will be omitted herein when it is considered that the detailed description makes the key subject matter of the present disclosure unclear.
Unless the context clearly dictates otherwise, it will be understood that when the term "comprises" or "comprising" is used in this specification, it specifies the presence of the stated elements, but does not preclude the presence or addition of one or more other elements. In addition, the term "control unit" used herein refers to a processing unit having at least one function or operation, and it may be implemented in hardware or software, alone or in combination.
Further, throughout the specification, it will also be understood that when an element is referred to as being "connected to" another element, it can be directly connected to the other element or intervening elements may be present.
In the present specification, the secondary battery may include one unit cell or a plurality of unit cells connected in parallel. A unit cell refers to a physically separable self-contained battery having a negative terminal and a positive terminal. For example, a pouch type lithium polymer battery may be considered as the unit.
Fig. 1 is a schematic view illustrating connections between components of an apparatus for measuring voltage and a
Referring to fig. 1, the
The battery module BM may include a plurality of
As shown in the configuration of fig. 1, the bus bar B may connect one end (e.g., a negative terminal) of at least one of the plurality of
As shown in the configuration of fig. 1, the
The plurality of voltage input terminals V0, V1, V2, V3, V4, V5, V6 may be electrically connected to both ends of each of the plurality of
Accordingly, the plurality of voltage input terminals V0, V1, V2, V3, V4, V5, V6 may receive voltages across the plurality of
The first ground terminal G1 may be electrically connected to a reference ground BG, which is electrically connected to the negative terminal MV-of the battery module BM. The reference ground BG may be electrically connected to a negative terminal MV-of the battery module BM through a wiring having a resistor RG. Specifically, the first ground terminal G1 may be directly connected to the reference ground BG. With this configuration, the
Preferably, the measuring
The
Preferably, the
In addition, the
In addition, the
In addition, the
<
Here, DCIRi denotes the DCIR of the secondary battery 1I, I denotes the magnitude of the current flowing through the
In addition, the
In addition, the reference voltage input terminal V0 may be electrically connected to the second reference ground N0, and the second reference ground N0 is connected to one end of the bus bar B. Specifically, the reference voltage input terminal V0 may be connected to the second reference ground N0 directly connected to one end of the bus bar B to receive a voltage applied to the second reference ground N0.
The
For example, the voltage of the first
In particular, reference voltage input terminal V0 may be electrically separated from reference ground BG within
Further, the
Preferably, the
Fig. 2 is a schematic diagram illustrating a connection between the device for
Referring to fig. 1 and 2, an
Preferably, a reference potential for sensing a voltage across each of the plurality of
Here, the components of the BMS may be mounted in the printed circuit board P in the form of a chip or a circuit. For example, the reference ground BG may be mounted in the printed circuit board P by being soldered to a circuit. Alternatively, the reference voltage input terminal V0 may be in contact with the printed circuit board P. For example, the printed circuit board P may be a Printed Circuit Board (PCB).
Specifically, the first wiring L1 and the second wiring L2 may be electrically separated from each other on the printed circuit board P. That is, the first wiring L1 and the second wiring L2 may be configured such that they are electrically separated from each other on the printed circuit board P.
Preferably, the first wiring L1 and the second wiring L2 may be configured to prevent the flow of charge/discharge current. In detail, the first and second wirings L1 and L2 may be electrically isolated from each other on the printed circuit board P such that the first and second wirings L1 and L2 may be separated from each other to prevent a current from flowing therebetween. That is, the reference voltage input terminal V0 may be electrically connected to the second reference ground N0 through a first wiring L1, and the reference ground BG may be electrically connected to the negative terminal MV-of the battery module through a second wiring L2 electrically separated from the first wiring L1 in the BMS. With this configuration, in contrast to the conventional art, the
For example, as shown in the configuration of fig. 2, the device 2e may have a first wiring line L1 and a second wiring line L2 electrically separated from each other on the printed circuit board P for electrical isolation between the charging/discharging path L and the BMS to prevent current from flowing from the charging/discharging path L into the BMS. For example, the charge/discharge current passing through the second reference ground N0 on the charge/discharge path L flows in the bus bar B, not in the first wiring L1. In addition, the charge/discharge current passing through the bus bar B does not flow into the second wiring L2, but flows through the negative terminal MV-of the battery module.
Fig. 3 is a table for reference in describing an operation of the apparatus for measuring
Referring to fig. 1 and 3, the
Specifically, there is no large deviation among the voltages of the secondary batteries measured before ① discharge, ② discharge, and ③ associated with the voltages of the secondary batteries before and after discharge in the plurality of
For example, referring to the
The
The
Fig. 4 is a schematic diagram illustrating connections between components of the
Referring to fig. 4 and 5, the device for measuring
In addition, the
Here, referring to fig. 1 and 4, in the case of the
<
V1=CV1+V0
In
In the case of the
<
Here, V1 is the voltage applied to the first voltage input terminal V1, V0 is the voltage applied to the reference voltage input terminal V0, CV1 is the voltage across the first
Fig. 6 is a table for reference in describing an operation of the
Fig. 6 shows an exemplary table 400 for the
Specifically, when the first record 402 of the plurality of records 402, 404, 406, 408, 410, 412 is compared with the second to
For example, referring to the first record 402, the voltage of the secondary battery measured after discharge is 2.002V, and when compared with the second to sixth records 404, 406, 408, 410, 412 showing the distribution of 2.038V to 2.043V, a deviation of 0.0385V on average may occur. In addition, in the case of the first record 402, the DCIR is 0.94 Ω, and a deviation of 0.1875 Ω on average may occur when compared with the second to sixth records 404, 406, 408, 410, 412 showing a distribution of 0.74 Ω to 0.765 Ω.
Therefore, in the case of the
Fig. 7 is a schematic flow chart diagram illustrating a method of measuring voltage according to one embodiment of the present disclosure. In fig. 7, the object to perform each step may be each component of the apparatus for measuring
As shown in fig. 7, in step S100, the
In step S110, the
In addition, when the control logic is implemented in software, the
In addition, if at least one of the control logics can be combined, and the combined control logic can be written in a computer-readable encoding system to allow a computer to access and read, there is no particular limitation on the type of the control logic of the control unit. For example, the recording medium includes at least one selected from the group consisting of a ROM, a RAM, a register, a CD-ROM, a magnetic tape, a hard disk, a floppy disk, and an optical data recording apparatus. In addition, the encoding system may be stored and executed in computers that are connected in a distributed manner via a network. In addition, functional programs, codes, and code segments for implementing the combinational control logic may be easily inferred by programmers skilled in the art to which the present disclosure pertains.
Although the present disclosure has been described above with respect to a limited number of embodiments and drawings, the present disclosure is not limited thereto, and those skilled in the art can make various modifications and changes within the technical aspects of the present disclosure and the equivalent scope of the appended claims.
Although the term "unit" such as "measurement unit" and "control unit" is used herein, it refers to a logical component unit, and it is obvious to those skilled in the art that the term does not necessarily indicate a component that may or should be physically separated.
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