Battery management device and method for manufacturing a battery management device

Abstract

A battery management device and a manufacturing method thereof can suppress unintended fuse blowout with a simpler structure. The battery management device includes a battery cell, a substrate having a wiring, a fuse connected to the wiring, a resistor generating heat in the vicinity of the fuse, a field effect transistor opening and closing a current path of the resistor, a protection IC controlling an operation of the field effect transistor, a first extension portion extending from the wiring between the protection IC and a gate of the field effect transistor, and a second extension portion extending from the wiring connected to a source of the field effect transistor, an end portion of the first extension portion and an end portion of the second extension portion having exposed portions where a protective film of the substrate is not formed, and the end portion of the first extension portion and the end portion of the second extension portion are not connected.

Description

Technical Field

[0001] This invention relates to a battery management device and a method for manufacturing the battery management device. Background Technology

[0002] If the battery voltage rises abnormally due to overcharging of the secondary battery, the battery may catch fire. Therefore, to prevent this, a fuse is usually installed in the current path connected to the battery. However, due to errors in the battery installation process, unexpected abnormal voltages may sometimes occur, causing the fuse to blow.

[0003] Patent Document 1 describes a structure in which two switches are installed on the current supply path to a resistive heating element that causes a fuse mounted on a substrate connected to multiple batteries to blow. Furthermore, Patent Document 1 describes an anomaly detection circuit and an operation confirmation circuit. The anomaly detection circuit detects an abnormal battery voltage and closes one of the two switches, while the operation confirmation circuit closes the other switch if it detects current flowing when the multiple batteries are normally connected. According to the structure of Patent Document 1, the other switch is open before the multiple batteries are normally connected, therefore the fuse will not blow even if an abnormal voltage is applied due to assembly errors.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-027798 Summary of the Invention

[0007] However, in the structure of Patent Document 1, the other two switches on the current supply path to the resistive heating element that causes the fuse to blow are only set to suppress abnormal voltages caused by assembly errors, inevitably increasing costs due to these components. Furthermore, the structure of Patent Document 1 requires sufficient substrate space for mounting these components, making it unsuitable for structures where such substrate space cannot be guaranteed.

[0008] The present invention was made in view of the above-mentioned problems, and its object is to provide a battery management device that can suppress unexpected fuse blowing with a simpler structure, as well as a method for manufacturing the battery management device.

[0009] A battery management device according to one aspect of the present invention includes: a battery cell; a substrate forming wiring connected to the battery cell; a fuse connected to the wiring; a resistor disposed near the fuse and generating heat; a field-effect transistor configured to switch the conduction and non-conduction of current from the battery cell relative to the resistor; a circuit connected to the battery cell, providing an operating voltage to the gate of the field-effect transistor to enable conduction between the source and drain of the field-effect transistor based on an anomaly in the output voltage of the battery cell; a first extension extending from the wiring between the circuit and the gate; and a second extension extending from the wiring connected to the source, wherein the ends of the first extension and the second extension have exposed portions of a protective film without a substrate, and the ends of the first extension and the second extension are not connected.

[0010] Another aspect of the present invention discloses a method for manufacturing a battery management device, comprising: a first step, firstly forming wiring connecting a battery cell; then, providing the following components: a fuse connected to the wiring; a resistor disposed near the fuse and generating heat; a field-effect transistor configured to switch the conduction and non-conduction of current from the battery cell relative to the resistor; and a circuit connected to the battery cell, providing an operating voltage to the gate of the field-effect transistor to establish conduction between the source and drain of the field-effect transistor based on an abnormality in the output voltage of the battery cell; and finally, connecting a substrate with conduction between the gate and source of the field-effect transistor to the battery cell; and a second step, performing processing to make the conduction path between the gate and source of the field-effect transistor, which is conduction in the substrate, become a non-conducting conduction path.

[0011] According to the present invention, unexpected fuse blowing can be suppressed with a simpler structure. Attached Figure Description

[0012] Figure 1 This is a circuit diagram showing the main structure of a battery management device.

[0013] Figure 2 This is a circuit diagram showing the main structure of a battery management device.

[0014] Figure 3 This is a schematic diagram illustrating an example of the circuit mounting structure near a field-effect transistor in its state before assembly is complete.

[0015] Figure 4 yes Figure 3 A-A' sectional view.

[0016] Figure 5This is a schematic diagram illustrating an example of the circuit mounting structure near a field-effect transistor in its assembled state.

[0017] Figure 6 yes Figure 5 A-A' sectional view.

[0018] Figure 7 This is a schematic diagram illustrating an example of the circuit mounting structure near a field-effect transistor in its assembled state.

[0019] Figure 8 yes Figure 7 A-A' sectional view.

[0020] Figure 9 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary between the first and second extensions in the state before assembly is completed.

[0021] Figure 10 yes Figure 9 The B-B' sectional view.

[0022] Figure 11 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary between the first and second extensions in the assembled state.

[0023] Figure 12 yes Figure 11 The B-B' sectional view.

[0024] Figure 13 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary between the first and second extensions in the state before assembly is completed.

[0025] Figure 14 yes Figure 13 The C-C' sectional view.

[0026] Figure 15 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary between the first and second extensions in the assembled state.

[0027] Figure 16 yes Figure 15 The C-C' sectional view.

[0028] Figure 17 This is a flowchart illustrating the manufacturing process of a battery management device that connects to battery cells.

[0029] Explanation of reference numerals in the attached figures

[0030] 1, 2: Battery management device; 9, 902: Substrate; 11, 12, 13, 14, 15: Battery cell; 20: Protection IC; 21, 22, 23, 24, 25: Voltage comparator; 26: Control circuit; 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40: Wiring; 41, 43: Branch point; 42: First extension; 44: Second extension; 45: Connection part; 5 0, 501, 502: Exposed portion; 503: Removed portion; 65: Field-effect transistor; 70, 71, 72, 73, 74, 75: Connecting terminals; 76, 77, 78, 79, 80: Reference voltage generating portion; 81, 82, 83, 84, 85: Voltage dividing resistor; 90: Substrate; 91, 95: Resist; 421: Removal marks; 452, 454, 455: Bonding metal; 453: Jumper wire. Detailed Implementation

[0031] The embodiments are described in detail below based on the accompanying drawings. It should be noted that the present invention is not limited to these embodiments. Of course, each embodiment is merely illustrative, and the structures shown in different embodiments can be partially replaced or combined. From Embodiment 2 onwards, descriptions of matters common to Embodiment 1 are omitted, and only the differences are explained. In particular, the same effects produced by the same structure are not mentioned sequentially in each embodiment.

[0032] (Implementation Method 1)

[0033] Figure 1 This is a circuit diagram showing the main structure of the battery management device 1. The battery management device 1 includes a battery cell, a positive terminal 5 connected to the battery cell, and a negative terminal 6. Figure 1 In the example, four battery cells 11, 12, 13, and 14 are connected in series as battery cells connected to the positive terminal 5 and the negative terminal 6. The battery cells are, for example, rechargeable lithium-ion battery cells, but are not limited to this, and may also be other rechargeable batteries.

[0034] The battery management device 1 includes a protection circuit 60. The protection circuit 60 serves as a mechanism to suppress the possibility of the battery cell catching fire due to overcharging or overheating. Upon detecting an output indicating overcharging or overheating, it blocks the charging and discharging current by melting the circuit connected to the battery cell.

[0035] Figure 1 The protection circuit 60 shown includes fuses 61 and 62 and a resistor 63. Resistor 63, located near fuses 61 and 62, is a resistor that generates heat. When current flows through resistor 63, it heats up and melts fuses 61 and 62. Unless fuses 61 and 62 melt, they function as conductors.

[0036] The positive terminals and positive terminals 5 of multiple battery cells connected in series are connected via wiring 35 and fuses 61 and 62. The negative terminals and negative terminals 6 of multiple battery cells connected in series are connected via wiring 31.

[0037] One end of resistor 63 is connected to wiring 35 via fuse 61. The other end of resistor 63 is connected to one end of wiring 39. The other end of wiring 39 is connected to the drain of field-effect transistor 65 (see reference). Figure 3 The field-effect transistor 65 is, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). The field-effect transistor 65 is configured to switch the source-drain connection between on and off states based on the voltage applied to the gate. The source of the field-effect transistor 65 (see reference) Figure 3 The gate of the field-effect transistor 65 is connected to the wiring via wiring 40 and wiring 31. Figure 3 It is connected to the protection IC (Integrated Circuit) 20 via wiring 38.

[0038] The battery management device 1 includes a protection IC 20 that controls the operation of the protection circuit 60. This IC controls the opening and closing of the energizing path that allows current to flow through the resistor 63. Figure 1 In the structure shown, the negative terminal of battery cell 11 is connected to wiring 31. Wiring 31 and protection IC 20 are connected via wiring 36, which branches off from wiring 31. The positive terminal of battery cell 11 and the negative terminal of battery cell 12 are connected to protection IC 20 via wiring 32. The positive terminal of battery cell 12 and the negative terminal of battery cell 13 are connected to protection IC 20 via wiring 33. The positive terminal of battery cell 13 and the negative terminal of battery cell 14 are connected to protection IC 20 via wiring 34. The positive terminal of battery cell 14 is connected to wiring 35. Wiring 35 and protection IC 20 are connected via wiring 37, which branches off from wiring 35.

[0039] In the event of an abnormal applied voltage from one or more of the multiple battery cells, a voltage deviating from the normal voltage range of a predetermined battery cell is applied to the protection IC 20 via any one of wirings 36, 32, 33, 34, and 37. In the event of an abnormal applied voltage from one or more of the multiple battery cells, the protection IC 20 outputs a signal to conduct the source-drain junction of the field-effect transistor 65 located on the energized path between wirings 35 and 31, which includes a resistor 63. The signal output from the protection IC 20 is provided to the gate of the field-effect transistor 65 via wiring 38, functioning as the voltage to conduct the source-drain junction of the field-effect transistor 65. When the source-drain junction of the field-effect transistor 65 is in the conducting state, current from the multiple battery cells flows into the resistor 63, causing the resistor 63 to heat up. As a result, fuses 61 and 62 are blown.

[0040] Furthermore, when multiple battery cells are connected to the protection IC 20, the protection IC 20, protection circuit 60, field-effect transistor 65, and wiring connecting these components are mounted on a substrate (not shown). Additionally, multiple battery cells connected in series are connected to a battery cell positioned closer to the negative electrode side. Figure 1 In the structure shown, battery cells 11, 12, 13, and 14 are connected in sequence. If the person assembling the battery management device 1 does not follow this connection sequence and connects the battery cells and protection IC 20, or if there is a wiring error in connecting the battery cells, an overvoltage may sometimes be applied from the battery cells to the protection IC 20. Sometimes this overvoltage causes the protection IC 20 to activate. That is, sometimes this overvoltage generates heat in the resistor 63 due to the conduction between the source and drain of the field-effect transistor 65, causing fuses 61 and 62 to blow. Thus, sometimes fuses 61 and 62 are blown due to errors in the assembly process of the battery management device 1.

[0041] Therefore, in the battery management device 1, a mechanism is provided to prevent conduction between the source and drain of the field-effect transistor 65 even if an overvoltage is mistakenly applied from the battery cell to the protection IC 20 during the assembly process. Specifically, the first extension 42 extends from the branch point 41 of the wiring 38, and the second extension 44 extends from the branch point 43 of the wiring 40. The first extension 42 and the second extension 44 continue to the assembly completion moment when all the battery cells are correctly connected to the protection IC 20. An exposed portion 50 of the first extension 42 and the second extension 44 is provided to be cut off after assembly. This results in a state where the fuses 61 and 62 corresponding to the operation of the protection IC 20 can be activated. Hereinafter, the state described as the state after assembly is completed refers to the state after the exposed portions 50 of the first extension 42 and the second extension 44 are cut off, unless otherwise specified. In addition, if the description is of the state before assembly is completed, unless otherwise specified, it refers to the state before the exposed portion 50 of the first extension 42 and the second extension 44 is cut off.

[0042] Figure 2 This is a circuit diagram showing the main structure of battery management device 2. Figure 2 In the example, five battery cells 11, 12, 13, 14, and 15 are shown as battery cells connected to the protection IC20. Only one or more battery cells need to be connected to the protection IC20, the positive terminal 5, and the negative terminal 6.

[0043] like Figure 2 As shown, the protection circuit 60 for protecting IC20, the field-effect transistor 65, and the wiring connected to them are mounted on substrate 9. Connection terminals 70, 71, 72, 73, 74, and 75 are provided on substrate 9. Connection terminal 70 is connected to wiring 31 and wiring 36. Connection terminal 71 is connected to wiring 32. Connection terminal 72 is connected to wiring 33. Connection terminal 73 is connected to wiring 34. Connection terminal 74 is connected to wiring 30. Connection terminal 75 is connected to wiring 35 and wiring 37.

[0044] The negative terminal of battery cell 11 is connected to connection terminal 70. The positive terminal of battery cell 11 and the negative terminal of battery cell 12 are connected to connection terminal 71. The positive terminal of battery cell 12 and the negative terminal of battery cell 13 are connected to connection terminal 72. The positive terminal of battery cell 13 and the negative terminal of battery cell 14 are connected to connection terminal 73. The positive terminal of battery cell 14 and the negative terminal of battery cell 15 are connected to connection terminal 74, thereby connecting to protection IC 20 via wiring 30. The positive terminal of battery cell 15 is connected to connection terminal 75. Unless otherwise specified, Figure 2The connection of battery cells 11, 12, 13, 14, and 15, which are battery units, and protection IC 20, as shown. Figure 1 The battery cells 11, 12, 13, and 14 shown as battery units have the same connection as the protection IC 20.

[0045] It should be noted that, in Figure 2 In this diagram, the connection terminals 70, 71, 72, 73, 74, and 75 are assigned the numbers "0", "1", "2", "3", "4", and "5" to indicate the connection order of the battery cells. Specifically, the connection is performed first with the battery cells assigned smaller values. More specifically, first, the negative terminal of battery cell 11 is connected to the connection terminal 70 assigned "0". Next, the positive terminal of battery cell 11 and the negative terminal of battery cell 12 are connected to the connection terminal 71 assigned "1". Thereafter, similarly, the connection is performed sequentially for the connection terminals assigned smaller values. Figure 2 The connection of the structure shown.

[0046] Protection IC 20 has voltage comparators 21, 22, 23, 24, and 25. Voltage comparators 21, 22, 23, 24, and 25 are comparators that output a value corresponding to the potential difference between one (+) and the other (-) of two inputs. Wiring 32 is connected to one (+) input of voltage comparator 21. Wiring 33 is connected to one (+) input of voltage comparator 22. Wiring 34 is connected to one (+) input of voltage comparator 23. Wiring 30 is connected to one (+) input of voltage comparator 24. Wiring 37 is connected to one (+) input of voltage comparator 25.

[0047] The positive terminals of the reference voltage generating units 76, 77, 78, 79, and 80 are connected to the other side (-) of the inputs of the voltage comparison units 21, 22, 23, 24, and 25. Figure 2 In this configuration, a reference voltage generating unit 76 is connected to the voltage comparison unit 21. A reference voltage generating unit 77 is connected to the voltage comparison unit 22. A reference voltage generating unit 78 is connected to the voltage comparison unit 23. A reference voltage generating unit 79 is connected to the voltage comparison unit 24. A reference voltage generating unit 80 is connected to the voltage comparison unit 25.

[0048] Voltage divider resistors 81, 82, 83, 84, and 85 are connected to the negative terminal side of the reference voltage generating sections 76, 77, 78, 79, and 80. These voltage divider resistors 81, 82, 83, 84, and 85 are resistors. Figure 2In this configuration, one end of voltage divider resistor 81 is connected to wiring 36 between the negative terminal of reference voltage generating section 76 and connection terminal 70. The other end of voltage divider resistor 81 and one end of voltage divider resistor 82 are connected to wiring 32 between the negative terminal of reference voltage generating section 77 and connection terminal 71. The other end of voltage divider resistor 82 and one end of voltage divider resistor 83 are connected to wiring 33 between the negative terminal of reference voltage generating section 78 and connection terminal 72. The other end of voltage divider resistor 83 and one end of voltage divider resistor 84 are connected to wiring 34 between the negative terminal of reference voltage generating section 79 and connection terminal 73. The other end of voltage divider resistor 84 and one end of voltage divider resistor 85 are connected to wiring 30 between the negative terminal of reference voltage generating section 80 and connection terminal 74. The other end of voltage divider resistor 85 is connected to wiring 37 between connection terminal 75 and voltage comparator section 25.

[0049] Reference voltage generating units 76, 77, 78, 79, and 80 provide a voltage corresponding to the normal voltage range of the battery cell to the other side (-) of the input to the comparator (voltage comparator units 21, 22, 23, 24, and 25). That is, the comparator output generated by reference voltage generating units 76, 77, 78, 79, and 80 when the battery cell output is within the normal voltage range differs from the comparator output when the battery cell output deviates from the normal voltage range. Hereinafter, when referred to as abnormal output, unless otherwise specified, it refers to the comparator output when the battery cell output deviates from the normal voltage range. It should be noted that the normal voltage range refers to a pre-set voltage range corresponding to the assumed output of the battery cell. For example, the normal voltage range is determined by... Figure 2 The voltage range generated by each of the battery cells 11, 12, 13, 14, and 15 shown is the voltage range when the battery cells 11, 12, 13, 14, and 15 operate as designed, but the normal voltage range is not limited to this and can be set arbitrarily as appropriate.

[0050] It should be noted that the resistance values ​​of voltage divider resistors 81, 82, 83, 84, and 85 are not strictly related to the accuracy of the protection IC 20's voltage measurement of each individual battery cell. Furthermore, voltage divider resistors 81, 82, 83, 84, and 85 have a structure that displays very large resistance values ​​to suppress the current consumption of the battery cells. Based on these factors, the accuracy of the resistance values ​​of voltage divider resistors 81, 82, 83, 84, and 85 may not be strictly defined.

[0051] The protection IC 20 also has a control circuit 26. The control circuit 26 outputs a signal to the wiring 38 to turn on the source-drain of the field-effect transistor 65 based on any one or more abnormal outputs of the voltage comparators 21, 22, 23, 24, and 25.

[0052] Unless otherwise specified, the battery management device 2 is functionally identical to the reference device. Figure 1 The battery management device 1 described herein is the same. For example, the protection IC 20 of the battery management device 1 may have the same characteristics as the referenced one. Figure 2 The protection IC20 described herein has the same circuit structure and can have the same function, but the detailed structure is different.

[0053] It should be noted that, compared with the reference Figure 1 The descriptions are the same, such as Figure 2 As shown, the battery management device 2 also includes an exposed portion 50 that cuts off the first extension 42 and the second extension 44 after assembly. The specific manner and method of forming the exposed portion 50 will be described below.

[0054] Figure 3 This is a schematic diagram illustrating an example of the circuit mounting structure near the field-effect transistor 65 before assembly is complete. Figure 4 yes Figure 3 The A-A' cross-sectional view. It should be noted that one of the two directions along the surface of substrate 9 is designated as the X direction, and the other as the Y direction. The X and Y directions are orthogonal. Furthermore, the direction orthogonal to both the X and Y directions is designated as the Z direction. It should be noted that, in the case of the upper side or on the substrate, this refers to relative to... Figure 4 The first extension 42 and the second extension 44 sides of the substrate 90 shown.

[0055] For reference Figure 1 As explained, wiring 38 is connected to the gate of the field-effect transistor 65. Wiring 40 is also connected to the source of the field-effect transistor 65. Wiring 38 and the first extension 42 are connected via a branch point 41. That is, the first extension 42 is also connected to the gate of the field-effect transistor 65. Wiring 40 and the second extension 44 are connected via a branch point 43. That is, the second extension 44 is also connected to the source of the field-effect transistor 65.

[0056] Additionally, in its state before assembly is complete, such as Figure 3 As shown, the first extension 42 and the second extension 44 are connected, for example, via a connecting portion 45. The first extension 42, the second extension 44, and the connecting portion 45 are wirings mounted on the substrate 9.

[0057] In addition, such as Figure 4As shown, substrate 9 has a substrate 90 and a resist 91. The substrate 90 is a plate-shaped component on which various wirings, including a first extension 42 and a second extension 44, are stacked. After the various wirings, including the first extension 42 and the second extension 44, are mounted, the resist 91 is provided as a protective film covering the mounting surface of the wirings on the substrate 90. The resist 91 functions as a protective film for the wirings. Figure 4 As shown, the first extension 42 and the second extension 44 are located between the substrate 90 and the resist 91.

[0058] Figure 5 This is a schematic diagram illustrating an example of the circuit mounting structure near the field-effect transistor 65 in its assembled state. Figure 6 yes Figure 5 A-A' sectional view. For example... Figure 5 As shown, in Embodiment 1, the exposed portion 50 is formed by removing a portion of the first extension 42 and a portion of the second extension 44. Thus, as... Figure 6 As shown, the exposed portion 50 exposes the substrate 90 and is not covered by the resist 91. Thus, the ends of the first extension 42 and the second extension 44 have exposed portions 50 where the protective film of the substrate 9 is not formed, and the ends of the first extension 42 and the second extension 44 are not connected. Furthermore, in the exposed portion 50, a portion of the wiring is exposed from the cross-sections of the ends of the first extension 42 and the second extension 44.

[0059] The exposed portion 50 is formed after the assembly of all battery cells and the protection IC 20 is completed in the correct steps, using a tool such as a laser that can optically remove the pattern wiring provided on the substrate, such as the first extension portion 42 and the second extension portion 44. Examples of such lasers include UV (Ultra Violet) lasers, but they are not limited to these; any laser that can render the patterns of the first extension portion 42 and the second extension portion 44 non-conductive can be used.

[0060] It should be noted that, in Figure 5 as well as Figure 6In this embodiment, the exposed portion 50 is formed by removing a portion of the first extension 42 and the second extension 44, but the specific manner and method of forming the exposed portion 50 are not limited thereto. For example, the exposed portion 50 may be formed by removing all of the first extension 42 and the second extension 44, or by removing a portion or all of the connecting portion 45. The exposed portion 50 in Embodiment 1 only needs to include a portion in which at least a portion of one or more of the first extension 42, the second extension 44, and the connecting portion 45 is removed to sever the electrical connection between the source and gate of the field-effect transistor 65. It should be noted that when the exposed portion 50 is formed using optical effects such as lasers, it has been observed that the substrate of the exposed portion 50 discolors due to burn-off.

[0061] For reference Figure 3 as well as Figure 4 As explained, the state before assembly completion in Embodiment 1 is a state in which the gate-source of the field-effect transistor 65, which is used in the mechanism to blow the fuses 61 and 62 of the protection circuit 60, is short-circuited through a patterned wiring such as the connection portion 45. That is, the state before assembly completion is a state in which the conduction between the source and drain of the field-effect transistor 65, corresponding to the voltage applied to the gate of the field-effect transistor 65, is disabled. In the state before assembly completion, even if a step error occurs, such as incorrect connection sequence of the voltage lines of each cell, when connecting the battery cell and the protection IC 20, the fuses 61 and 62 will not blow.

[0062] As an example assuming the absence of the connecting part 45, another example is given where the battery cell connection position is incorrect. Figure 2 If the positive terminal of battery cell 13 is incorrectly connected to connection terminal 72 instead of connection terminal 73, the voltage of both battery cell 12 and battery cell 13 will be applied to the voltage comparator 22. Therefore, the voltage comparator 22 outputs a signal to the control circuit 26 indicating that an overvoltage outside the normal voltage range has been applied. Consequently, the control circuit 26 establishes conduction between the source and drain of the field-effect transistor 65, and fuses 61 and 62 are blown.

[0063] As another example assuming the absence of connection part 45, consider an error in the battery cell connection process. In the connection of battery cells 11, 12, 13, 14, and 15 connected in series, if connection terminal 75 is connected to the positive terminal of battery cell 15 after connection terminal 70 is connected to the negative terminal of battery cell 11, the total voltage of battery cells 11, 12, 13, 14, and 15—that is, the voltage divided by voltage divider resistors 81, 82, 83, 84, and 85—is input to voltage comparators 21, 22, 23, 24, and 25. Here, as mentioned above, the resistance of voltage divider resistors 81, 82, 83, 84, and 85 is sometimes not precise. Therefore, when there is a deviation in the resistance of voltage divider resistors 81, 82, 83, 84, and 85, it is possible to apply an overvoltage outside the normal voltage range to a portion of voltage comparators 21, 22, 23, 24, and 25. In this case, fuses 61 and 62 also blow. Furthermore, even if the battery cell is connected to the connection terminals 71, 72, 73, 74, and 75 without connecting the connection terminal 70 to the negative terminal of the battery cell 11, it is possible to apply an overvoltage that deviates from the normal voltage range to a portion of the voltage comparison units 21, 22, 23, 24, and 25.

[0064] Even assuming that connectors are provided for connecting terminals 70, 71, 72, 73, 74, 75 to battery cells 11, 12, 13, 14, 15, it is difficult to control the connection order of the connector pins, and therefore it is difficult to eliminate the possibility of such an incident occurring if an error occurs in the above-described battery cell connection steps.

[0065] As described above, considering the phenomena that may occur if the connecting part 45 is not present, by providing a structure that short-circuits the first extension 42 and the second extension 44 as the connecting part 45, the unexpected melting of fuses 61 and 62 can be suppressed.

[0066] On the other hand, as referenced Figure 5 as well as Figure 6 As explained, after assembly, the short circuit between the gate and source of the field-effect transistor 65 is removed by forming the exposed portion 50. Therefore, even if an abnormality occurs where the voltage generated by the battery cell output deviates from the normal voltage range, the protection IC 20 activates, establishing conduction between the source and drain of the field-effect transistor 65 corresponding to the voltage applied to the gate of the field-effect transistor 65, thus triggering a circuit protection mechanism that blows fuses 61 and 62.

[0067] As described above, the battery management device 1 and battery management device 2 of Embodiment 1 include: battery cells 11, 12, 13, 14, 15, etc.; a substrate 9, on which wiring such as wiring 31, 35 is formed to connect the battery cells; fuses 61, 62, connected to the wiring connecting the battery cells; a resistor 63, disposed near the fuses 61, 62, generating heat; a field-effect transistor 65, configured to switch the conduction and non-conduction of current from the battery cells relative to the resistor 63; and a protection IC 20, connected to the battery cells, which is a circuit protection IC. Based on the abnormality of the output voltage of the battery cell, an operating voltage is provided to the gate of the field-effect transistor 65 to enable conduction between the source and drain of the field-effect transistor 65; a first extension 42 extends from the wiring between the protection IC 20 and the gate of the field-effect transistor 65; and a second extension 44 extends from the wiring connected to the source of the field-effect transistor 65. The ends of the first extension 42 and the second extension 44 have exposed portions 50 where the protective film of the substrate 9 is not formed. The ends of the first extension 42 and the second extension 44 are not connected.

[0068] Thus, the exposed portion 50 removes the short circuit between the gate and source of the field-effect transistor 65, ensuring that even if an abnormality occurs due to the output of the battery cell causing the voltage to deviate from the normal voltage range, the mechanism for fuses 61 and 62 to blow is established. On the other hand, before forming the exposed portion 50, even if the protection IC 20 unexpectedly activates due to an assembly error such as a connection error between the battery cell and the protection IC 20, the blowing of fuses 61 and 62 can be prevented. Therefore, forming the exposed portion 50 means that unexpected blowing of fuses 61 and 62 can be prevented with a simpler structure before forming the exposed portion 50. Therefore, manufacturing defects in battery management devices 1 and 2 caused by unexpected blowing of fuses 61 and 62 can be suppressed, potentially improving yield.

[0069] In addition, a portion of the wiring is exposed from the cross-sections of the ends of the first extension 42 and the second extension 44. Since the exposed portion 50 can be formed simply by removing the wiring formed on the substrate 9, unexpected fuse blowing can be suppressed with a simpler structure before the exposed portion 50 is formed, and the formation of the exposed portion 50 can be made easier.

[0070] Furthermore, the exposed portion 50 is formed through optical action. Therefore, it is unnecessary to add circuitry to the mechanism for suppressing manufacturing defects in battery management devices 1 and 2 caused by unexpected fuse blowouts 61 and 62, and unexpected fuse blowouts 61 and 62 can be suppressed with a more inexpensive and space-saving structure. Additionally, manufacturing defects caused by malfunctions of the operation confirmation circuit or another of the two switches, as described in Patent Document 1, will also be avoided, thus improving yield rates.

[0071] Furthermore, according to the first embodiment, even if a failure of the field-effect transistor 65 occurs due to noise or other issues during the connection between the battery cell and the protection IC20, the unexpected blowing of the fuses 61 and 62 can still be suppressed.

[0072] Above, refer to Figure 5 as well as Figure 6 The exposed portion 50 of Embodiment 1 has been described, but the specific manner in which the structure functions in the same way as the exposed portion 50 and the method of its formation are not limited thereto. Hereinafter, the specific manner in which the structure functions in the same way as the exposed portion 50 and the method of its formation will be described.

[0073] (Implementation Method 2)

[0074] Figure 7 This is a schematic diagram illustrating an example of the circuit mounting structure near the field-effect transistor 65 in its assembled state. Figure 8 yes Figure 7 A-A' sectional view. For example... Figure 7 As shown, in Embodiment 2, an exposed portion 501 is formed, the exposed portion 501 including a state before assembly is completed (see reference). Figure 3 The area below which a first extension 42 and a portion of a second extension 44 are formed. For example... Figure 8 As shown, the exposed portion 501 is formed by removing a portion of the substrate 90, the first extension 42, and the second extension 44, as well as the resist 91 on that portion, by removing the substrate 90. Therefore, the exposed portion 50 is in a state where the substrate 90 is exposed and is not covered by the resist 91.

[0075] The exposed portion 501 is formed after the assembly of all battery cells and the protection IC 20 is completed in the correct steps, using a tool such as a cutting tool that can physically cut the pattern wiring provided on the substrate, such as the first extension 42 and the second extension 44, together with the substrate 90. The exposed portion 501 in Embodiment 2 functions in the same way as the exposed portion 50 in Embodiment 1. It should be noted that in the case of cutting, it is possible to observe the portion of the substrate that is cut away from the cutting portion.

[0076] The exposed portion 501 is formed in place of the exposed portion 50 in Embodiment 1. Except as otherwise specifically stated, Embodiment 2 is the same as Embodiment 1.

[0077] As described above, according to Embodiment 2, since the exposed portion 50 is formed by cutting, it is not necessary to add circuitry to the mechanism for suppressing manufacturing defects in the battery management device 1 or battery management device 2 caused by unexpected fuse blowouts 61 and 62. Unexpected fuse blowouts 61 and 62 can be suppressed using a cheaper and more space-saving structure. Furthermore, Embodiment 2 achieves the same effects as Embodiment 1 described above.

[0078] (Implementation Method 3)

[0079] Figure 9 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary of the first extension 42 and the second extension 44 before assembly is completed. Figure 10 yes Figure 9 The B-B' cross-sectional view. In embodiment 3, as... Figure 9 As shown, the first extension 42 and the second extension 44, in their pre-assembly state, are connected via a joining metal 452. Specifically, as... Figure 10 As shown, in Embodiment 3, the first extension 42 and the second extension 44, mounted on the substrate 90, are positioned opposite each other in a direction orthogonal to the Z-direction, separated by a gap 46. A bonding metal 452 is disposed above the first extension 42, the gap 46, and the second extension 44, which are mounted on the upper side of the substrate 90, thereby connecting the first extension 42 and the second extension 44. The bonding metal 452 is, for example, solder, but may also be so-called lead-free solder or other bonding metals.

[0080] Figure 11 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary of the first extension 42 and the second extension 44 in the assembled state. Figure 12 yes Figure 11 The B-B' cross-sectional view. In embodiment 3, after assembly, the (see reference) Figure 11 , Figure 12 A joining metal 452 (see reference) is provided on the upper side of the first extension 42, the gap 46, and the upper side of the second extension 44 of the substrate 90 before assembly is completed. Figure 9 , Figure 10 Thus, by removing the joining metal 452, the conductive connection between the first extension 42 and the second extension 44 is released, resulting in an exposed portion 502. In Embodiment 3, the exposed portion 502, including the gap 46, functions similarly to the exposed portion 50 in Embodiment 1. Furthermore, in Figure 11, Figure 12 Although not explicitly illustrated, in Embodiment 3, where the exposed portion 502 is formed by removing the bonding metal 452, the bonding metal is exposed at least one of the ends of the first extension 42 and the second extension 44. Here, the exposed bonding metal is a residue of a portion of the bonding metal 452 formed before removal. Figure 12 In the diagram, removal marks 421 are schematically shown as part of the remaining bonding metal 452. Therefore, when the bonding metal 452 is used, the bonding metal can be observed at at least one of the ends of the first extension 42 and the second extension 44. Furthermore, a portion of the bonding metal 452 does not remain to the extent that it fills the non-connecting portion formed by the gap 46 and connects the first extension 42 and the second extension 44.

[0081] The exposed portion 502 is formed instead of the exposed portion 50 in Embodiment 1. Except as otherwise specifically stated, the third embodiment is the same as the first embodiment.

[0082] As described above, according to Embodiment 3, at least one of the ends of the first extension 42 and the second extension 44 exposes the bonding metal. The removal mark of this bonding metal is, for example, the removal mark 421 described above. This indicates that the connection between the first extension 42 and the second extension 44 is established by the bonding metal 452. Therefore, the bonding metal 452 can suppress the unexpected melting of fuses 61 and 62 before the connection between the battery cell and the protection IC 20 is completed, and by removing the bonding metal 452 to form the exposed portion 502, the mechanism involved in the melting of fuses 61 and 62 can be established. In other words, no special structure is required except for the space of the substrate 9 involved in the formation and removal of the bonding metal 452. Furthermore, according to Embodiment 3, the effects of Embodiment 1 described above can be achieved in the same way.

[0083] (Implementation Method 4)

[0084] Figure 13 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary of the first extension 42 and the second extension 44 before assembly is completed. Figure 14 yes Figure 13 A C-C' cross-sectional view. In embodiment 4, as... Figure 13 As shown, the first extension 42 and the second extension 44 are connected via jumper 453 in the state before assembly is completed.

[0085] Specifically, such as Figure 14As shown, in Embodiment 4, the first extension 42 and the second extension 44, mounted on the substrate 90, are positioned opposite each other in a direction orthogonal to the Z direction, separated by a gap 47. The opposite surfaces of the first extension 42 and the second extension 44 are covered by a resist 95, separated by the substrate 90.

[0086] Additionally, a hole 93 penetrating the substrate 902 in the Z direction is provided on the first extension 42, and this substrate 902 serves as the substrate instead of the substrate 9 in Embodiment 4. Furthermore, a hole 94 penetrating the substrate 902 in the Z direction is provided on the second extension 44. One end of the jumper 453 is inserted into the hole 93 and connected to the first extension 42 via a bonding metal 454. The other end of the jumper 453 is inserted into the hole 94 and connected to the second extension 44 via a bonding metal 455. The jumper 453 connects the hole 93 and the hole 94 on the resist 95 side.

[0087] Figure 15 This is a schematic diagram illustrating an example of a circuit mounting structure near the boundary of the first extension 42 and the second extension 44 in the assembled state. Figure 16 yes Figure 15 A C-C' cross-sectional view. In embodiment 4, after assembly, as shown... Figure 16 As shown, a portion of the jumper 453 is removed on the resist 95 side to form a removal portion 503, thereby terminating the connection between the first extension 42 and the second extension 44 based on the jumper 453. The removal portion 503 in Embodiment 4 functions in the same way as the exposed portion 50 in Embodiment 1.

[0088] It should be noted that in embodiment 4, simply cutting the jumper 453 is sufficient to disconnect the first extension 42 from the second extension 44. Figure 15 as well as Figure 16 In the example shown, by forming a removal portion 503 that removes a portion of the jumper 453, the extension length of the jumper 453 used to connect the first extension 42 and the second extension 44 is physically lost, thus more reliably generating a non-connected state between the first extension 42 and the second extension 44.

[0089] The removed portion 503 is formed in place of the exposed portion 50 in Embodiment 1. Except as otherwise specifically stated, Embodiment 4 is the same as Embodiment 1.

[0090] As described above, according to Embodiment 4, the unexpected melting of fuses 61 and 62 before the connection between the battery cell and the protection IC 20 is completed can be suppressed by jumper 453, and the mechanism involved in the melting of fuses 61 and 62 can be established by the formation of the removal part 503. In other words, no special structure is required except for the space of the substrate 9 involved in the formation of jumper 453 and the removal of a part of it. Therefore, the unexpected melting of fuses can be suppressed with a simpler structure. In addition, the removal part 503 can be easily confirmed by visual inspection. Therefore, it is easier and more reliable to confirm whether the mechanism involved in the melting of fuses 61 and 62 is established.

[0091] Figure 17 This is a flowchart illustrating the manufacturing process of a battery management device connected to battery cells. First, the circuit board is manufactured (step S1). In step S1, for example, in reference... Figure 1 The battery management device 1 described herein is manufactured in a manner other than the battery cells 11, 12, 13, 14, 15 and the exposed portion 50. Furthermore, in step S1, for example, the following is performed: Figure 2 The structure of the battery management device 2 described herein includes the manufacture of all structures except for the battery cells 11, 12, 13, 14, 15 and the exposed portion 50. At the completion of step S1, the first extension 42 and the second extension 44 are turned on.

[0092] After the processing in step S1, the circuit board manufactured in step S1 is connected to the battery cell (step S2). At the completion of step S2, the first extension 42 and the second extension 44 are turned on. After the processing in step S2, the first extension 42 and the second extension 44 are cut off (step S3). For a specific example, please refer to... Figure 5 as well as Figure 6 Exposed portion 50, as described, reference Figure 7 as well as Figure 8 Exposed part 501 as described, reference Figure 11 as well as Figure 12 Exposed portion 502 as described or referenced Figure 15 as well as Figure 16 The formation of any one of the removal parts 503 as described.

[0093] Thus, the manufacturing process of battery management device 1 and battery management device 2 includes: a first step (step S2), in which wiring (wiring 31, 35, etc.) connecting battery cells 11, 12, 13, 14, 15, etc. is formed; then, the following components are installed: fuses 61 and 62 connected to the wiring; a resistor 63 disposed near the fuses 61 and 62 to generate heat; a field-effect transistor 65 configured to switch the conduction and non-conduction of current from the battery cell relative to the resistor 63; and a... The protection IC20 for the circuit is connected to the battery cell. According to the abnormality of the output voltage of the battery cell, the operating voltage is provided to the gate of the field-effect transistor 65 to enable the conduction between the source and drain of the field-effect transistor 65. Finally, the substrate 9, which enables the conduction between the gate and source of the field-effect transistor 65, is connected to the battery cell. The second process (step S3) is to process the conduction path between the gate and source of the field-effect transistor 65 that is conducting in the substrate 9 to become a non-conducting conduction path.

[0094] Therefore, after performing the second step described above, the short circuit between the gate and source of the field-effect transistor 65 is removed, and even if an abnormality occurs due to the output of the battery cell causing the voltage to deviate from the normal voltage range, the mechanism for fuses 61 and 62 to blow is established. On the other hand, before performing the second step described above, even if the protection IC 20 is accidentally activated due to an assembly error such as a connection error between the battery cell and the protection IC 20, the blowing of fuses 61 and 62 can be prevented. Therefore, manufacturing defects in battery management device 1 and battery management device 2 caused by unexpected blowing of fuses 61 and 62 can be prevented, and the yield rate is expected to be improved.

[0095] It should be noted that the above embodiments are for ease of understanding of the embodiments of the present invention and are not intended to limit or explain the embodiments of the present invention. The present invention can be modified / improved without departing from its spirit, and the present invention also includes its equivalents.

[0096] For example, voltage comparators 21, 22, 23, 24, and 25 can also be operational amplifiers that function in the same way as comparators.

Claims

1. A battery management device, characterized in that, include: Battery cell; A substrate is formed to provide wiring for connection to the battery cell; A fuse, connected to the wiring; A resistor, positioned near the fuse, generates heat. A field-effect transistor, configured to switch the conduction and non-conduction of current from the battery cell relative to the resistor; The circuit is connected to the battery cell and, based on an anomaly in the output voltage of the battery cell, provides an operating voltage to the gate of the field-effect transistor to enable the conduction between the source and drain of the field-effect transistor. A first extension extends from the wiring between the circuit and the gate; as well as The second extension extends from the wiring connected to the source electrode. The ends of the first extension and the second extension have exposed portions where a protective film without a substrate is formed. The end of the first extension is not connected to the end of the second extension.

2. The battery management device according to claim 1, wherein, A portion of the wiring is exposed from the cross-section of the end of the first extension and the end of the second extension.

3. The battery management device according to claim 2, wherein, The exposed portion is formed by optical action.

4. The battery management device according to claim 2, wherein, The exposed portion is formed by cutting.

5. The battery management device according to claim 1, wherein, At least one of the ends of the first extension and the second extension exposes the metal for joining.

6. A method for manufacturing a battery management device, characterized in that, include: First step, Forming wiring to connect the battery cells, The system includes a fuse, a resistor, a field-effect transistor (FET), and a circuit. The fuse is connected to the wiring. The resistor is positioned near the fuse and generates heat. The FET is configured to switch the current from the battery cell between the conducting and non-conducting states relative to the resistor. The circuit is connected to the battery cell and, based on an anomaly in the battery cell's output voltage, provides an operating voltage to the gate of the FET to enable conduction between the source and drain of the FET. The substrate with the gate-source of the field-effect transistor connected is connected to the battery cell; as well as The second step involves processing the conduction path that makes the gate-source conduction path of the field-effect transistor that is conducting in the substrate non-conducting.

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