Battery abnormality monitoring system

Abstract

To accurately detect a battery cell which generates heat abnormally.SOLUTION: A battery abnormality monitor system 5 includes: a bus bar 30 for electrically connecting external terminals 22 of a battery cell 20; a bridging unit 32 which is electrically connected to the bus bar 30, can be inclined to a direction closer to the external terminal 22, and bridges the external terminals 22 and the bus bar 30 together; a heat melted member 40 for supporting the bridging unit 32 so that the bridging unit 32 is not in contact with the external terminals 22, the heat melted member melting by heat; a voltage measuring unit 50 for measuring the voltage of the bus bar 30; and an abnormality determination unit 62 for determining an abnormal battery cell 20 on the basis of the voltage.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery abnormality monitoring system.

Background Art

[0002] Patent Document 1 discloses a battery including a container, a positive electrode terminal attached to a lid portion of the container, a negative electrode terminal attached to the lid portion, and a connection mechanism for electrically connecting the positive electrode terminal and the negative electrode terminal. The connection mechanism is configured such that when a specific member melts due to an increase in the temperature of the battery, the positive electrode terminal and the negative electrode terminal are electrically connected. Thereby, self-discharge is started when the temperature rises, and the battery is returned to a safer state.

[0003] By the way, in a battery, it is preferable to accurately detect a battery cell that has abnormally generated heat.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In consideration of the above facts, an object of the present invention is to accurately detect a battery cell that has abnormally generated heat.

Means for Solving the Problems

[0006] A battery abnormality monitoring system according to a first aspect of the present invention comprises: a busbar that electrically connects the terminals of a battery cell; a bridging portion that is electrically connected to the busbar and configured to be tiltable toward the terminals, bridging the terminals and the busbar; a heat-melting member that supports the bridging portion so as not to come into contact with the terminals and melts with heat; a voltage measuring instrument that measures the voltage of the busbar; and an abnormality determination unit that determines an abnormal battery cell based on the voltage.

[0007] In the battery abnormality monitoring system of the second aspect of the present invention, the bridging portion is biased in the direction toward the terminal, as in the battery abnormality monitoring system of the first aspect of the present invention.

[0008] In a third aspect of the battery abnormality monitoring system of the present invention, in the battery abnormality monitoring system of the first or second aspect of the present invention, the terminal is provided with a protruding pin that protrudes upward from the busbar, and the tip surface of the protruding pin is inclined.

[0009] In a fourth aspect of the present invention, in a battery abnormality monitoring system according to any one of the first to third aspects of the present invention, the terminal is provided with a protruding pin that protrudes upward from the busbar, and the bridging portion is set to a length that protrudes from the protruding pin when the bridging portion bridges the terminal and the busbar.

[0010] In the fifth aspect of the present invention, the battery abnormality monitoring system is attached to the busbar in any one of the first to fourth aspects of the present invention.

[0011] In the sixth aspect of the present invention, in the battery abnormality monitoring system of any one of the first to fifth aspects of the present invention, the voltage measuring instrument measures the voltage between the busbars connected to the same battery cell. [Effects of the Invention]

[0012] In the battery abnormality monitoring system according to the first aspect of the present invention, a bridging portion is electrically connected to the busbar and configured to be tiltable toward the terminal, bridging the terminal and the busbar; and a heat-melting member supports the bridging portion so as not to contact the terminal, and which melts with heat. When the melting member melts with heat, the bridging portion comes into contact with the terminal. When the bridging portion comes into contact with the terminal, the conductive path between the busbar and the terminal increases, the contact resistance between the busbar and the terminal decreases, and the voltage drops. By determining an abnormal battery cell based on the measured busbar voltage, it is possible to accurately detect a battery cell that has overheated abnormally.

[0013] In the battery abnormality monitoring system according to the second aspect of the present invention, the bridging portion is biased toward the terminal, so that when the heat-melting member melts due to heat, the bridging portion moves toward the terminal. Therefore, when the heat-melting member melts due to heat, the bridging portion can be brought into contact with the terminal. As a result, the detection accuracy of abnormally overheating battery cells can be improved.

[0014] In the battery abnormality monitoring system of the third aspect of the present invention, the tip surface of the protruding pin is inclined, which increases the contact area of ​​the bridging portion compared to the case where the tip surface of the protruding pin is formed flat. As a result, the amount of voltage drop when the bridging portion contacts the terminal increases. Consequently, abnormally overheated battery cells can be detected with high accuracy.

[0015] In the battery abnormality monitoring system according to the fourth aspect of the present invention, the bridging portion is set to a length that protrudes from the protruding pin when the bridging portion bridges the terminal and the busbar. Compared to the case where the bridging portion is set to a length that does not protrude from the protruding pin, the contact area of ​​the bridging portion is increased. Therefore, the amount of voltage drop when the bridging portion contacts the terminal increases. As a result, abnormally overheated battery cells can be detected with high accuracy.

[0016] In the battery abnormality monitoring system according to the fifth aspect of the present invention, the thermally fusible member is attached to the bus bar, so that the thermally fusible member melts early when the bus bar generates heat. Therefore, an abnormally heated battery cell can be quickly detected. As a result, the occurrence of seal-out can be prevented or detected early.

[0017] [[ID=P4]]In the battery abnormality monitoring system according to the sixth aspect of the present invention, the voltage measuring device measures the voltage between the bus bars connected to the same battery cell, so that the change in the voltage of a single battery cell is measured. Therefore, an abnormally heated battery cell can be identified.

Brief Description of the Drawings

[0018] [Figure 1] It is a perspective view schematically showing a battery module according to an embodiment. [Figure 2] It is a top view schematically showing a battery module according to an embodiment. [Figure 3] It is a cross-sectional view schematically showing a battery cell according to an embodiment, showing a cross-section A-A of FIG. [Figure 4] It is a cross-sectional view schematically showing a battery cell according to an embodiment, showing a state where the thermally fusible member has melted and the bridging portion has contacted the terminal. [Figure 5] It is a graph explaining the voltage measured by the voltage measuring device according to an embodiment. [[ID=P25]] [Figure 6] It is a block diagram showing the functional configuration of a battery abnormality monitoring system according to an embodiment. [Figure 7] It is a flowchart showing the flow of battery abnormality monitoring processing by a battery abnormality monitoring system according to an embodiment. [Figure 8] It is a cross-sectional view schematically showing a battery cell according to another embodiment. [Figure 9] It is a cross-sectional view schematically showing a battery cell according to another embodiment.

Modes for Carrying Out the Invention

[0019] It should be noted that there seems to be an error in the numbering in the original text. The text marked as [[ID=P4]] should probably be for a more consistent numbering system. Also, the text marked as [[ID=P25]] should probably be . This translation has been adjusted accordingly while maintaining the integrity of the original text and following the translation rules.Hereinafter, a battery abnormality monitoring system according to an embodiment will be described with reference to the drawings. The battery abnormality monitoring system according to the embodiment will be described by taking, for example, an example of monitoring battery abnormalities of a plurality of battery cells (single cells) 20 that constitute a battery module 10 used as an in-vehicle power source for an electric vehicle, a hybrid vehicle, or the like.

[0020] In each figure, arrow D indicates the longitudinal direction D of the battery cell 20, arrow E indicates the width direction E of the battery cell 20, and arrow F indicates the vertical direction F of the battery cell 20.

[0021] [Configuration of Battery Module 10] As shown in FIG. 1, the battery module 10 includes a plurality of battery cells 20, a bus bar 30, and a thermally fusible member 40. A voltage measuring device 50 is connected to the bus bar 30.

[0022] (Battery Cell 20) The battery cell 20 includes a housing 21 having an accommodation space inside, and an external terminal 22 as a terminal.

[0023] The housing 21 is formed in a rectangular box shape extending in the longitudinal direction D. Inside the housing 21, an electrode body (not shown) and an electrolytic solution (not shown) are hermetically accommodated.

[0024] The external terminal 22 is provided on the upper part of the housing 21 so as to be exposed to the outside. On one end side in the longitudinal direction D of the external terminal 22, a negative electrode external terminal or a positive electrode external terminal is provided, and on the other end side in the longitudinal direction D, a negative electrode external terminal or a positive electrode external terminal is provided.

[0025] <External Terminal 22> As shown in FIG. 3, the external terminal 22 is formed of a conductive material such as aluminum or copper, and includes a base portion 23 and a protruding pin 24.

[0026] The base portion 23 is formed in the shape of a rectangular plate with the vertical direction F being the thickness direction. The base portion 23 is electrically connected to the current collector provided on the electrode body inside the housing 21.

[0027] The protruding pin 24 is formed in a cylindrical shape that protrudes upward from the base 23. The tip surface of the protruding pin 24 is an inclined surface 24A that is tilted with respect to the horizontal direction.

[0028] As shown in Figure 1, the multiple battery cells 20 are arranged in a line along the width direction E such that the wide surfaces of the housing 21 in the width direction E face each other. The battery cells 20 are arranged so that the negative external terminals and positive external terminals are alternately aligned along the width direction E. The positive external terminals and negative external terminals of adjacent battery cells 20 are electrically connected via busbars 30.

[0029] (Bus bar 30) As shown in Figures 2 and 3, the busbar 30 is made of a conductive material such as aluminum or copper, and comprises a base portion 31 and a bridging portion 32.

[0030] The busbars 30 are arranged to electrically connect the external terminals 22 of adjacent battery cells 20 in the width direction E. One busbar 30 is located on the external terminal 22 at one end in the longitudinal direction D of a single battery cell 20, and another busbar 30 is located on the external terminal 22 at the other end in the longitudinal direction D. When the busbar 30 located on the external terminal 22 at one end in the longitudinal direction D is connected to the external terminal 22 of an adjacent battery cell 20 on one side in the width direction E, the busbar 30 located on the external terminal 22 at the other end in the longitudinal direction D is connected to the external terminal 22 of an adjacent battery cell 20 on the other side in the width direction E.

[0031] <Base section 31> As shown in Figures 2 and 3, the base portion 31 is formed in the shape of a rectangular plate with the vertical direction F being the thickness direction and extending in the width direction E. The base portion 31 is positioned to straddle the space between the external terminals 22 of each adjacent battery cell 20.

[0032] The base portion 31 is joined to the base portion 23 of the external terminal 22 by welding. This electrically connects each battery cell 20, thus constructing the battery module 10. The base portion 31 may also be joined to the base portion 23 of the external terminal 22 by bolting or other means.

[0033] The base portion 31 has two openings 31A formed side by side in the width direction E. The openings 31A are formed as rectangular through holes that penetrate the base portion 31 in the thickness direction. A protruding pin 24 is inserted into the openings 31A, and the protruding pin 24 protrudes upward from the base portion 31. Note that the shape of the openings 31A is not limited to rectangles, and may be circular or polygonal, for example.

[0034] <Bridging section 32> A bridge section 32 is formed in each opening 31A. The bridge section 32 is formed in the shape of a rectangular plate extending in the longitudinal direction D. The width of the bridge section 32 is smaller than the width of the opening 31A.

[0035] The bridging portion 32 is formed integrally with the base portion 31 and is electrically connected to the base portion 31. The base portion 31 and the bridging portion 32 can be formed by press-forming a single sheet of metal. The bridging portion 32 is configured to be tiltable in the direction toward the protruding pin 24 of the external terminal 22. The bridging portion 32 is formed by bending in the elastic deformation region. As a result, the bridging portion 32 is biased toward the protruding pin 24 of the external terminal 22. In a free state where no external force is acting, the bridging portion 32 contacts the inclined surface 24A of the protruding pin 24, thereby electrically connecting the base portion 31 and the protruding pin 24 of the external terminal 22.

[0036] As shown in Figure 4, the length of the bridging portion 32 is set so that when the bridging portion 32 contacts the inclined surface 24A of the protruding pin 24 and electrically connects the base portion 31 and the protruding pin 24 of the external terminal 22, it protrudes by a length L from the protruding pin 24.

[0037] (Heat-melting member 40) As shown in Figures 1 and 3, the heat-melting member 40 is stretched across the opening 31A. The heat-melting member 40 is attached to the base portion 31 of the busbar 30 by means of, for example, an adhesive. The heat-melting member 40 supports the bridging portion 32 so that it does not come into contact with the protruding pin 24 of the external terminal 22.

[0038] The heat-melting member 40 is made of a material that melts with heat. The material of the heat-melting member 40 can be one that melts at a temperature higher than the maximum heat generation temperature during normal use of the battery module 10, but lower than the allowable load temperature of the sealing material arranged around the external terminals 22, or the melting temperature of the separator constituting the electrode body. The material of the heat-melting member 40 can be, for example, a resin such as polypropylene or polyethylene.

[0039] (Voltage measuring instrument 50) As shown in Figures 1 and 2, the lead wires 51 of the voltage measuring instrument 50 are connected to each busbar 30. The voltage measuring instrument 50 measures the voltage between busbars 30 connected to the same battery cell 20.

[0040] [Abnormal overheating of battery cell 20] In the battery cell 20, poor contact between the busbar 30 and the external terminal 22 increases the contact resistance during charging and discharging of the battery module 10, causing the busbar 30 to overheat abnormally.

[0041] [Operation of busbar 30 during abnormal heat generation] As shown in Figure 3, during normal use of the battery module 10, the bridging portion 32 is supported by the heat-melting member 40, and the bridging portion 32 does not come into contact with the protruding pin 24 of the external terminal 22.

[0042] As shown in Figure 4, when the busbar 30 overheats abnormally, the heat-melting member 40 melts, causing the bridging portion 32 to tilt toward the protruding pin 24 of the external terminal 22, contacting the inclined surface 24A of the protruding pin 24 and electrically connecting the base portion 31 and the protruding pin 24 of the external terminal 22.

[0043] [Voltage during normal operation and during abnormal overheating] When the bridging portion 32 contacts the protruding pin 24, the conduction path between the external terminal 22 and the busbar 30 increases. When the battery module 10 is charged and discharged, an increase in the conduction path between the external terminal 22 and the busbar 30 reduces resistance and lowers voltage. As a result, as shown in Figure 5, a voltage difference is created between the voltage V1 between the busbars 30 connected to a normal battery cell 20 and the voltage V2 between the busbars 30 connected to a battery cell 20 that has overheated abnormally. The battery abnormality monitoring system 5 performs an inspection abnormality monitoring process to identify the battery cell 20 that has overheated abnormally based on this voltage difference.

[0044] [Functional Configuration of Battery Anomaly Monitoring System] As shown in Figure 6, in the battery abnormality monitoring system 5, the voltage measured by the voltage measuring instrument 50 is input to the control unit 60, and the processing result of the battery abnormality monitoring process executed by the control unit 60 is output to the output unit 70. The control unit executes the inspection abnormality monitoring process according to the program recorded in the storage unit 64.

[0045] (Voltage measuring instrument 50) The voltage measuring device 50 measures the voltage between busbars 30 connected to the same battery cell 20.

[0046] (Control unit 60) The control unit 60 is configured as a processor and is installed, for example, in a vehicle. Functionally, the control unit 60 includes a voltage acquisition unit 61, an abnormality detection unit 62, a notification unit 63, and a storage unit 64.

[0047] The voltage acquisition unit 61 acquires the voltage measured by the voltage measuring instrument 50.

[0048] The abnormality determination unit 62 determines that a battery cell 20 has overheated abnormally based on the voltage measured by the voltage measuring instrument 50. Specifically, the abnormality determination unit 62 refers to the current value during charging and discharging, calculates the difference between the measured voltage and the voltage that should be there, and determines that the battery cell 20 has overheated abnormally if this difference is greater than or equal to a threshold.

[0049] When the abnormality detection unit 62 determines that the battery cell 20 is overheating abnormally, the notification unit 63 outputs notification information about the overheating battery cell 20 to the output unit 70.

[0050] The memory unit 64 stores a program for performing inspection abnormality monitoring and information on the voltage value that should ideally be present in the current value during charging and discharging.

[0051] (Output section 70) The output unit 70 outputs notification information about the abnormally overheated battery cell 20. The output unit 70 may be an image output device that outputs images, or an audio output device that outputs sound.

[0052] [Battery abnormality monitoring process flow] As shown in Figure 7, when the inspection abnormality monitoring process is started, the voltage acquisition unit 61 acquires the voltage measured by the voltage measuring instrument 50 (step S101). Next, the abnormality determination unit 62 refers to the current value during charging and discharging and determines whether the difference between the voltage measured by the voltage measuring instrument 50 and the voltage that should be there is greater than or equal to a threshold (step S102).

[0053] If it is determined that the difference between the voltage measured by the voltage measuring device 50 and the voltage that should be present is greater than or equal to a threshold (YES in step S102), the process proceeds to step S103. On the other hand, if it is determined that the difference between the voltage measured by the voltage measuring device 50 and the voltage that should be present is not greater than or equal to a threshold (NO in step S102), the inspection abnormality monitoring process is terminated.

[0054] When the process proceeds to step S103, the notification unit 63 outputs notification information to the output unit 70 regarding the abnormally overheated battery cell 20, and the inspection abnormality monitoring process ends.

[0055] [Effect] The battery abnormality monitoring system 5 of the embodiment includes a busbar 30 that electrically connects the external terminals 22 of the battery cells 20, a bridging portion 32 that is electrically connected to the busbar 30 and configured to be tiltable toward the external terminals 22, bridging the external terminals 22 and the busbar 30, a heat-melting member 40 that supports the bridging portion 32 so as not to come into contact with the external terminals 22 and melts with heat, a voltage measuring instrument 50 that measures the voltage of the busbar 30, and an abnormality determination unit 62 that determines an abnormal battery cell 20 based on the voltage (see Figure 3).

[0056] The system includes a bridging portion 32 that is electrically connected to the busbar 30 and is configured to tilt toward the external terminal 22, bridging the external terminal 22 and the busbar 30, and a heat-melting member 40 that supports the bridging portion 32 so as not to contact the external terminal 22 and melts with heat. When the melting member melts with heat, the bridging portion 32 comes into contact with the external terminal 22. When the bridging portion 32 comes into contact with the external terminal 22, the conductive path between the busbar 30 and the external terminal 22 increases, the contact resistance between the busbar 30 and the external terminal 22 decreases, and the voltage drops. By determining the abnormal battery cell 20 based on the measured voltage of the busbar 30, it is possible to accurately detect the battery cell 20 that has overheated abnormally.

[0057] In the battery abnormality monitoring system 5 of this embodiment, the bridging portion 32 is biased in the direction toward the external terminal 22 (see Figure 3).

[0058] The bridging portion 32 is biased toward the external terminal 22, so when the heat-melting member 40 melts due to heat, the bridging portion 32 moves toward the external terminal 22. Therefore, when the heat-melting member 40 melts due to heat, the bridging portion 32 can be brought into contact with the external terminal 22. As a result, the detection accuracy of the abnormally overheated battery cell 20 can be improved.

[0059] In the battery abnormality monitoring system 5 of this embodiment, the external terminal 22 is equipped with a protruding pin 24 that protrudes upward from the bus bar 30, and the tip surface of the protruding pin 24 is inclined (see Figure 3).

[0060] Because the tip surface of the protruding pin 24 is inclined, the contact area of ​​the bridging portion 32 is increased compared to when the tip surface of the protruding pin 24 is formed flat. As a result, the voltage drop when the bridging portion 32 contacts the external terminal 22 increases. Consequently, abnormally overheated battery cells 20 can be detected with high accuracy.

[0061] In the battery abnormality monitoring system 5 of this embodiment, the bridging section 32 is set to a length that protrudes from the protruding pin 24 when the bridging section 32 bridges the external terminal 22 and the busbar 30 (see Figure 4).

[0062] The bridging portion 32 is set to a length that protrudes from the protruding pin 24 when it bridges the external terminal 22 and the busbar 30. Compared to the case where the bridging portion 32 is set to a length that does not protrude from the protruding pin 24, the contact area of ​​the bridging portion 32 is increased. Therefore, the voltage drop when the bridging portion 32 contacts the external terminal 22 increases. As a result, the abnormally overheated battery cell 20 can be detected with high accuracy.

[0063] By the way, when the temperature of the external terminals 22 and busbars 30 of the battery rises, the seals may deteriorate and become worn out. When the seals deteriorate, gaps will form in the seal area. This can lead to a situation called "seal-out," where the electrolyte evaporates through the gap.

[0064] In the battery abnormality monitoring system 5 of this embodiment, the heat melting member 40 is attached to the bus bar 30 (see Figure 3).

[0065] Since the heat-melting member 40 is attached to the busbar 30, the heat-melting member 40 melts quickly when the busbar 30 overheats. Therefore, abnormally overheated battery cells 20 can be quickly detected. As a result, the occurrence of seal-out can be prevented or detected early.

[0066] In the battery abnormality monitoring system 5 of this embodiment, the voltage measuring instrument 50 measures the voltage between busbars 30 connected to the same battery cell 20 (see Figure 2).

[0067] The voltage measuring device 50 measures the voltage between busbars 30 connected to the same battery cell 20, thereby measuring the voltage change of a single battery cell 20. This allows for the identification of a battery cell 20 that has overheated abnormally.

[0068] The battery abnormality monitoring system of the present invention has been described above based on the above embodiments. However, the specific configuration is not limited to these embodiments, and changes to the design are permitted as long as they do not depart from the gist of the invention as described in each claim of the patent.

[0069] In the above embodiment, an example was shown in which the tip surface of the protruding pin 24 is an inclined surface 24A that is tilted with respect to the horizontal direction. However, as shown in Figure 8, the tip surface of the protruding pin 124 may be a horizontal surface 124A. In this case, the bridging portion 132 may be formed in a bent shape so as to contact the horizontal surface 124A of the protruding pin 124 when it tilts toward the protruding pin 124 of the external terminal 22.

[0070] In the above embodiment, the heat-melting member 40 is shown to be attached to the base portion 31 of the busbar 30. However, as shown in Figure 9, the heat-melting member 140 may be attached to the side surface of the protruding pin 24. In this case, the heat-melting member 140 is formed of an insulating material.

[0071] In the above embodiment, an example was shown in which the bridging portion 32 is formed integrally with the base portion 31. However, the bridging portion 32 may be formed separately from the base portion and joined to the base portion by, for example, welding.

[0072] In the above embodiment, the bridging portion 32 is formed by bending in the elastic deformation region, thereby biasing it toward the protruding pin 24 of the external terminal 22. However, the bridging portion may also be provided with a biasing member such as a spring to bias it toward the protruding pin of the external terminal.

[0073] In the above embodiment, an example was shown in which the external terminal 22 is provided with a protruding pin 24. However, the external terminal does not have to be provided with a protruding pin. In this case, the bridging portion can move toward the external terminal when the heat-melting member melts, and come into contact with the external terminal to bridge the busbar and the external terminal.

[0074] In the above embodiment, the external terminal 22 is shown as being provided on the upper part of the housing 21, exposed to the outside. However, the external terminal may also be provided on the side of the housing, exposed to the outside. [Explanation of symbols]

[0075] 5. Battery Anomaly Monitoring System 20 battery cells 22 External terminals (examples of terminals) 24 Protruding pins 30 Bus Bar 32 Bridge section 40 Heat-melting components 50 Voltage Measuring Instruments 62 Abnormality determination section

Claims

1. A busbar that electrically connects the terminals of a battery cell, A bridging section is electrically connected to the busbar, configured to be tiltable in a direction approaching the terminal, and bridgings the terminal and the busbar, The bridging portion is supported so as not to come into contact with the terminal, and includes a heat-melting member that melts with heat, A voltage measuring instrument for measuring the voltage of the busbar, An abnormality determination unit that determines an abnormal battery cell based on the voltage, A battery abnormality monitoring system equipped with the following features.

2. The bridging portion is biased in a direction toward the terminal. The battery abnormality monitoring system according to claim 1.

3. The terminal is provided with a protruding pin that protrudes upward from the busbar. The tip surface of the aforementioned protruding pin is inclined. The battery abnormality monitoring system according to claim 1.

4. The terminal is provided with a protruding pin that protrudes upward from the busbar. The bridging portion is set to a length that protrudes from the protruding pin when the bridging portion bridges the terminal and the busbar. The battery abnormality monitoring system according to claim 1.

5. The heat-melting member is attached to the busbar. The battery abnormality monitoring system according to claim 1.

6. The voltage measuring instrument measures the voltage between the busbars connected to the same battery cell. The battery abnormality monitoring system according to claim 1.

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