Battery management system

Abstract

A battery management system includes a battery including battery cells connected in series, a diode connected in parallel to the battery cells, a switching unit including switches connected to the battery cells, respectively, a control unit detecting voltages of the battery cells and performing a battery balancing, and a sensing line connecting the battery cells and the control unit, wherein the control unit measures a first upper voltage difference between each battery cell and an adjacent upper battery cell in a state in which the switches are turned off, measures a second upper voltage difference between each battery cell and the adjacent upper battery cell after the switches are turned on for a predetermined time, and determines that a sensing line of a corresponding battery cell is disconnected when the second upper voltage difference is greater than the first upper voltage difference.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2021-0023915, filed on February 23, 2021, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments relate to a battery management system. Background Technology

[0004] Unlike non-rechargeable primary batteries, secondary batteries can be charged and discharged. Low-capacity secondary batteries can be used in portable small electronic devices such as smartphones, feature phones, laptops, and cameras, while high-capacity secondary batteries can be used in motors and batteries that power hybrid vehicles and electric vehicles.

[0005] The information disclosed in this background section is intended only to enhance understanding of the background of the described technology, and therefore may contain information that does not constitute prior art known to a person skilled in the art in this country. Summary of the Invention

[0006] The embodiment relates to a battery management system, including: a battery including a plurality of battery cells connected in series; a plurality of diodes connected in parallel with the plurality of battery cells; a switching unit including a plurality of switches respectively connected to the plurality of battery cells; a control unit for detecting the voltage of the plurality of battery cells and performing battery balancing; and a plurality of sensing lines connecting the plurality of battery cells and the control unit, wherein the control unit measures a first voltage difference between each battery cell and an adjacent upper battery cell when the switches are off, measures a second voltage difference between each battery cell and an adjacent upper battery cell after the switches are turned on for a predetermined time, and determines that the sensing line of the corresponding battery cell is disconnected when the second voltage difference is greater than the first voltage difference.

[0007] The control unit can measure the first voltage difference between each battery cell and the adjacent lower battery cell when the switch is off, and can measure the second voltage difference between each battery cell and the adjacent lower battery cell after the switch is turned on for a predetermined time. When the second voltage difference is greater than the first voltage difference, it can determine that the sensing line of the corresponding battery cell is disconnected.

[0008] The voltage of the corresponding battery cell can be measured by dividing the voltage between the diode connected to the corresponding battery cell and the diode connected to the upper battery cell.

[0009] When the switch is turned on, the voltage of the battery cell adjacent to the disconnected sensing line can increase.

[0010] When the switch is turned on, the voltage of the battery cell in the disconnected sensing line can be reduced.

[0011] When the switch is on, the voltage of the battery cell in the disconnected sensing line can correspond to the voltage of the adjacent lower battery cell.

[0012] In the switching unit, switches in even-numbered groups and switches in odd-numbered groups can be switched on alternately.

[0013] The control unit can turn on the switch for the even-numbered group to measure the voltage of the even-numbered battery cells, and then turn off the switch for the even-numbered group; similarly, it can turn on the switch for the odd-numbered group to measure the voltage of the odd-numbered battery cells, and then turn off the switch for the odd-numbered group. Attached Figure Description

[0014] Features will become apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, wherein:

[0015] Figure 1 This is a schematic diagram illustrating a battery management system according to an example embodiment.

[0016] Figures 2A to 2C This is a schematic diagram used to explain a method for detecting a break in a sensing line in a battery management system. Detailed Implementation

[0017] Example embodiments will now be described more fully below with reference to the accompanying drawings; however, they may be implemented in different forms and should not be construed as limiting themselves to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the example implementations to those skilled in the art.

[0018] In the accompanying drawings, the dimensions of layers and regions may be enlarged for clarity. It should also be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on that layer or substrate, or there may be intermediate layers. Furthermore, it should be understood that when a layer is referred to as being "below" another layer, it can be directly below that layer, and one or more intermediate layers may be present. Additionally, it should be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intermediate layers may be present. The same reference numerals always refer to the same elements.

[0019] As used herein, the term “and / or” includes any and all combinations of one or more of the related listed items. Furthermore, it should be understood that when element A is referred to as being “connected to” element B, element A can be directly connected to element B, or an intermediate element C can exist between them such that element A and element B are indirectly connected to each other.

[0020] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including” as used in this specification specify the presence of features, quantities, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, and / or combinations thereof.

[0021] It should be understood that although the terms first, second, etc., may be used herein to describe various components, elements, regions, layers, and / or parts, these components, elements, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one component, element, region, layer, and / or part from another. Thus, for example, the first component, first element, first region, first layer, and / or first part discussed below may be referred to as a second component, second element, second region, second layer, and / or second part without departing from the teachings of this disclosure.

[0022] Furthermore, the control unit (controller) and / or other related devices or components according to this disclosure can be implemented using any suitable hardware, firmware (e.g., application-specific semiconductors), software, or a suitable combination of software, firmware, and hardware. For example, various components of the control unit and / or other related devices or components according to this disclosure can be formed on a single integrated circuit chip or on a separate integrated circuit chip. Additionally, various components of the control unit can be implemented on a flexible printed circuit film and can be formed on a tape package, a printed circuit board, or the same substrate as the control unit.

[0023] Figure 1 This is a schematic diagram illustrating a battery management system according to an example embodiment.

[0024] Reference Figure 1 According to an example embodiment, the battery management system 100 includes a diode unit 120, a switching unit 130, a sensing unit 140, and a control unit 150. The battery management system 100 can be connected to a battery 110 to manage the battery 110.

[0025] Battery 110 may include a plurality of battery cells 111, 112, 113, 114 and 115, and may be charged or discharged at a constant voltage. In an example embodiment, battery 110 may include a plurality of battery cells 111, 112, 113, 114 and 115 connected in series.

[0026] Although battery 110 is Figure 1The diagram shows five battery cells 111, 112, 113, 114, and 115 connected in series, but the number of battery cells may be greater than or less than five. For illustrative purposes, battery 110 will be described as including a first battery cell 111, a second battery cell 112, a third battery cell 113, a fourth battery cell 114, and a fifth battery cell 115.

[0027] The first battery unit 111 may be a unit located on the negative terminal side of the battery 110, and the fifth battery unit 115 may be a unit located on the positive terminal side of the battery 110. The first battery unit 111 may be referred to as the bottommost battery unit, and the fifth battery unit 115 may be referred to as the topmost battery unit.

[0028] Diode unit 120 may include a plurality of diodes 121, 122, 123, 124, and 125 respectively connected in parallel to each of a plurality of battery cells 111, 112, 113, 114, and 115. The number of diodes 121, 122, 123, 124, and 125 may correspond to the number of battery cells 111, 112, 113, 114, and 115. For example, diode unit 120 may include a first diode 121, a second diode 122, a third diode 123, a fourth diode 124, and a fifth diode 125.

[0029] Even when at least one sensing line is disconnected, the multiple diodes 121, 122, 123, 124, and 125 can still allow measurement of the voltage of battery cells 111, 112, 113, 114, and 115. This will be described in more detail below.

[0030] The switching unit 130 may include a plurality of switches 131, 132, 133, 134, and 135 respectively connected to each of the plurality of battery cells 111, 112, 113, 114, and 115. For example, the switching unit 130 may include a first switch 131, a second switch 132, a third switch 133, a fourth switch 134, and a fifth switch 135.

[0031] The corresponding switches 131, 132, 133, 134 and 135 can connect / disconnect the discharge path of the corresponding battery cells 111, 112, 113, 114 and 115.

[0032] The sensing unit 140 may include multiple sensing lines 141, 142, 143, 144, and 145 for sensing the voltage of each of the plurality of battery cells 111, 112, 113, 114, and 115. For example, the sensing unit 140 may include a first sensing line 141, a second sensing line 142, a third sensing line 143, a fourth sensing line 144, and a fifth sensing line 145.

[0033] Multiple sensing lines 141, 142, 143, 144 and 145 can be connected to the front side of each battery cell 111, 112, 113, 114 and 115.

[0034] Switching unit 130 may include a discharge resistor connected to both ends of each of switches 131, 132, 133, 134, and 135 to perform cell balancing of battery cells 111, 112, 113, 114, and 115. For example, the discharge resistor may be connected between each end of each of switches 131, 132, 133, 134, and 135 and a corresponding sensing line of sensing lines 141, 142, 143, 144, and 145.

[0035] The control unit 150 can detect the voltage, current, temperature, etc. of the corresponding battery cells 111, 112, 113, 114, and 115 constituting the battery 110, and can control the battery balance of the battery 110. In an example embodiment, the control unit 150 may include a microprocessor, a central processing unit (CPU), and an application-specific integrated circuit (ASIC), such as an analog front end (AFE).

[0036] The control unit 150 can divide the switch units 130 into even-numbered groups and odd-numbered groups. The even-numbered groups may include switches 132 and 134. The odd-numbered groups may include switches 131, 133, and 135. The control unit 150 can alternately activate switches 132 and 134 in the even-numbered groups and switches 131, 133, and 135 in the odd-numbered groups to perform battery balancing. Therefore, compared to sequentially balancing multiple battery units 111, 112, 113, 114, and 115, the control unit 150 can reduce the time required for battery balancing.

[0037] Furthermore, the control unit 150 can measure the voltage of each battery cell 111, 112, 113, 114, and 115 before and after battery balancing to detect the disconnection of sensing lines 141, 142, 143, 144, and 145. This will now be described in more detail.

[0038] The method by which the control unit 150 detects the disconnection of sensing lines 141, 142, 143, 144, and 145 will be described in more detail below. As an example, the method by which the second sensing line 142 (connected to the second battery cell 112) is disconnected will be described. Figures 2A-2C (The case is represented by 'X' on the second sensing line 142).

[0039] Figures 2A-2C This is a schematic diagram used to explain a method for detecting a disconnected sensing line in a battery management system.

[0040] First, refer to Figure 2A The control unit 150 can measure the voltage of the corresponding battery cells 111, 112, 113, 114 and 115 when the switch unit 130 is off, for example when all switches 131, 132, 133, 134 and 135 are open or non-conductive.

[0041] Control unit 150 can measure the voltage of corresponding battery cells 111, 112, 113, 114, and 115 via sensing unit 140. In an example embodiment, control unit 150 can measure the sensed voltages V1, V2, V3, V4, and V5 of corresponding battery cells 111, 112, 113, 114, and 115 via sensing lines 141, 142, 143, 144, and 145. Control unit 150 can obtain the difference between the sensed voltages V1, V2, V3, V4, and V5 of each of the corresponding battery cells 111, 112, 113, 114, and 115 and the sensed voltage of the adjacent lower battery cell to measure the voltage of the corresponding battery cells 111, 112, 113, 114, and 115.

[0042] Even when any sensing line of the sensing unit 140 is disconnected (or open-circuited), the sensing voltage can be measured from the disconnected sensing line using the diode unit 120. For example, refer to Figure 2A When the sensing voltage V3 measured from the third sensing line 143 is 9V and the sensing voltage V1 measured from the first sensing line 141 is 3V, a sensing voltage V2 of 6V can be measured from the disconnected second sensing line 142 by using the voltage divider between the third diode 123 and the second diode 122. This sensing voltage V2 is the intermediate voltage between the third diode 123 and the second diode 122.

[0043] The control unit 150 can measure the voltage of the respective battery cells 111, 112, 113, 114 and 115 by obtaining the difference between the sensing voltage measured from each of the respective sensing lines 141, 142, 143, 144 and 145 and the sensing voltage measured from the adjacent lower sensing line.

[0044] For example, the control unit 150 can obtain the difference (V3-V2) between 9V (the sensing voltage V3 measured from the third sensing line 143) and 6V (the sensing voltage V2 measured from the second sensing line 142), thereby determining that the voltage of the third battery cell 113 is 3V.

[0045] Similarly, the control unit 150 can measure the difference (V2-V1) between 6V (the sensing voltage V2 measured from the second sensing line 142) and 3V (the sensing voltage V1 measured from the first sensing line 141) to determine that the voltage of the second battery cell 112 is 3V.

[0046] In the same manner as described above, the control unit 150 can obtain the voltages of the respective battery cells 111, 112, 113, 114 and 115.

[0047] Furthermore, when the switching unit 130 is turned off, the control unit 150 can define the voltage difference between each of battery cells 111, 112, 113, 114, and 115 and its adjacent upper battery cell as a first upper voltage difference, and define the voltage difference between each of battery cells 111, 112, 113, 114, and 115 and its adjacent lower battery cell as a first lower voltage difference, and then store them in a storage unit (not shown). Here, the first lower voltage difference means the voltage of each battery cell 111, 112, 113, 114, and 115.

[0048] Next, refer to Figure 2B The control unit 150 can turn on the switches 132 and 134 of the even-numbered group of the switching unit 130 to perform battery balancing for a predetermined period of time, and then measure the sensed voltage of the even-numbered battery cells 112 and 114 to turn off the switches 132 and 134 of the even-numbered group.

[0049] Then, refer to Figure 2C The control unit 150 can turn on the switches 131, 133 and 135 of the odd-numbered group to perform battery balancing for a predetermined period of time, and then measure the sensed voltage of the odd-numbered battery cells 111, 113 and 115 to turn off the switches 131, 133 and 135 of the odd-numbered group.

[0050] In an example embodiment, the battery balancing time can be set to within a few seconds.

[0051] When the sensing line is disconnected during battery balancing, the sensing voltage of the corresponding battery cell is measured, similar to the sensing voltage measured at the sensing line connected to the lower battery cell. Therefore, after battery balancing, the voltage difference between the sensing voltage of each battery cell and the sensing voltage of the adjacent lower battery cell becomes relatively lower than the voltage difference before battery balancing. In other words, in the battery cells connected to the disconnected sensing line, the voltage after battery balancing becomes lower than the voltage before battery balancing. Furthermore, since the voltage of the battery cells connected to the disconnected sensing line decreases, the voltage of the adjacent upper battery cells increases relatively. In addition, when the switching unit 130 is turned on, the control unit 150 can define the voltage difference between each battery cell 111, 112, 113, 114, and 115 and the adjacent upper battery cell as the second upper voltage difference, and define the voltage difference between each battery cell 111, 112, 113, 114, and 115 and the adjacent lower battery cell as the second lower voltage difference, and then store them in the storage unit. Here, the second voltage difference means the voltage of each of battery cells 111, 112, 113, 114 and 115 after battery balancing.

[0052] Thus, when the second lower voltage difference between each battery cell 111, 112, 113, 114, and 115 and its adjacent lower battery cell is less than the first lower voltage difference, the control unit 150 can determine that the sensing line of the corresponding battery cell is disconnected. Furthermore, when the first upper voltage difference between each battery cell 111, 112, 113, 114, and 115 and its adjacent upper battery cell is less than the second upper voltage difference, the control unit 150 can determine that the sensing line of the corresponding battery cell is disconnected.

[0053] For example, refer to again Figure 2B When the second switch 132 is turned on, the second battery cell 112 is not connected to the second sensing line 142, and therefore the voltage V2 is measured to be approximately 3V, which is similar to the voltage V1 measured from the first sensing line 141. Therefore, the control unit 150 can obtain the difference (V2-V1) between 3V (voltage V2 measured from the second sensing line 142) and 3V (voltage V1 measured from the first sensing line 141), thereby determining that the voltage of the second battery cell 112 is 0V. Furthermore, the control unit 150 can obtain the difference (V3-V2) between 9V (voltage V3 measured from the third sensing line 143) and 3V (voltage V2 measured from the second sensing line 142), thereby determining that the voltage of the third battery cell 113 is 6V.

[0054] Therefore, the control unit 150 can compare the first upper voltage difference between each of the battery cells 111, 112, 113, 114, and 115 and its upper battery cell before battery balancing with the second upper voltage difference between each of the battery cells 111, 112, 113, 114, and 115 and its upper battery cell after battery balancing, and determine that the sensing line of the corresponding battery cell is broken when the second upper voltage difference is greater than the first upper voltage difference. Furthermore, the control unit 150 can compare the first lower voltage difference between each of the battery cells 111, 112, 113, 114, and 115 and its lower battery cell before battery balancing with the second lower voltage difference between each of the battery cells 111, 112, 113, 114, and 115 and its lower battery cell after battery balancing, and determine that the sensing line of the corresponding battery cell is broken when the second lower voltage difference is less than the first lower voltage difference.

[0055] By summarizing and reviewing, it was found that in vehicles using rechargeable batteries, the performance of each battery directly affects the vehicle's performance. Therefore, the charging / discharging of each battery can be managed by measuring its voltage and current. For this purpose, a Battery Management System (BMS) can be used, which can stably control the corresponding battery by monitoring the state of the sensing cells of each battery.

[0056] As described above, the embodiments can provide a battery management system capable of detecting the disconnection of a sensing line in a battery cell. As described above, in the battery management system according to the exemplary embodiments, the disconnection of the sensing line can be detected by comparing the voltage difference between each battery cell and its adjacent cells when the switch is off with the voltage difference between each battery cell and its adjacent cells after the switch is on, thereby improving safety.

[0057] Example embodiments have been disclosed herein, and although specific terminology has been used, they are used and interpreted in a general and descriptive sense only and not for limiting purposes. In some instances, it will be apparent to those skilled in the art at the time of filing of this application that features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless specifically indicated otherwise. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. A battery management system, comprising: Multiple diodes are connected in parallel to multiple battery cells, and the multiple battery cells are connected in series. A switching unit, comprising multiple switches respectively connected to multiple battery cells; The control unit is configured to detect the voltage of multiple battery cells and perform battery balancing; as well as Multiple sensing lines connect to multiple battery units and control units. The control unit is further configured as follows: With the switch off, measure the first voltage difference between each battery cell and its adjacent upper battery cell. After a predetermined time has elapsed since the switch was turned on, the second voltage difference between each battery cell and its adjacent upper battery cell is measured, and When the second voltage difference is greater than the first voltage difference, it is determined that the sensing line of the corresponding battery cell is broken. The control unit is configured as follows: With the switch off, measure the first voltage difference between each battery cell and its adjacent lower battery cell. After a predetermined time has elapsed since the switch was turned on, the second voltage difference between each battery cell and its adjacent lower battery cell is measured, and When the second voltage difference is less than the first voltage difference, it is determined that the sensing line of the corresponding battery cell is disconnected.

2. The battery management system according to claim 1, wherein, The control unit is configured to: The voltage of the corresponding battery cell is measured using a disconnected sensing line by dividing the voltage between the diode connected to the corresponding battery cell and the diode connected to the upper battery cell.

3. The battery management system according to claim 1, wherein, When the switch is turned on, the voltage of the battery cell adjacent to the disconnected sensing line increases.

4. The battery management system as described in claim 1, wherein, When the switch is turned on, the voltage of the battery cell in the disconnected sensing wire decreases.

5. The battery management system as described in claim 1, wherein, When the switch is on, the voltage of the battery cell in the disconnected sensing line corresponds to the voltage of the adjacent lower battery cell.

6. The battery management system as described in claim 1, wherein, In the switching unit, switches in even-numbered groups and switches in odd-numbered groups are alternately turned on.

7. The battery management system according to claim 6, wherein, The control unit is configured to: Turn on the switch for the even-numbered group to measure the voltage of the even-numbered battery cells, then turn off the switch for the even-numbered group. Conversely, turn on the switch for the odd-numbered group to measure the voltage of the odd-numbered battery cells, then turn off the switch for the odd-numbered group.

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