Bus bar and power storage device

Abstract

The utility model provides a bus bar and an electrical storage device, even if a bus bar main body is in a complex shape, an insulating film is formed in an expected area, and stripping of the insulating film can be inhibited. The bus bar (20) has a bus bar main body (25) and an insulating film (10) formed on the surface of the bus bar main body (25). The bus bar main body (25) has a pair of main surface portions (25a) facing each other, a plurality of end surface portions (25b) connecting the facing main surface portions (25a) to each other, and corner portions (25c) formed between the main surface portions (25a) and the end surface portions (25b). The outer surface of the insulating film (10) formed on the corner (25c) of the bus bar main body (25) has a rounded shape. In addition, the film thickness of the insulating film (10) formed at the corner part (25c) of the bus bar main body (25) is greater than the film thickness of the insulating film (10) formed at the main surface part (25a) of the bus bar main body (25).

Description

Technical Field

[0001] The utility model relates to a bus bar and an electric storage device which connects a plurality of battery units or battery modules by using the bus bar. Background Art

[0002] Various electronic devices, electric vehicles (EVs) driven by electric motors, hybrid vehicles, etc., are equipped with power storage devices formed by connecting multiple battery cells in series or in parallel using bus bars. In addition, the battery cells mainly use lithium-ion secondary batteries that can achieve higher capacity and higher output than lead-acid batteries, nickel-hydrogen batteries, etc.

[0003] In a battery cell, when current flows during charging and discharging, the bus bar may heat up, and depending on the situation, flames may be generated. Therefore, the bus bar is required to have insulation and heat resistance. For example, Patent Document 1 describes a bus bar in which a ceramic tape such as a mica tape is wound around a copper bus bar body as a fire-resistant layer.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Chinese Utility Model No. 216902355 Utility Model Content

[0007] Technical problems to be solved by the utility model

[0008] However, in Patent Document 1, it is necessary to wind the ceramic tape around the bus bar body. Due to the space limitation of the battery unit installation location, the bus bar sometimes has a complex shape. If the bus bar has a complex shape, it is difficult to wind the ceramic tape around every corner of the bus bar body. If there is uneven winding or gaps in the ceramic tape, it is impossible to fully obtain insulation and heat resistance. In addition, it is also conceivable that the adhesive surface of the ceramic tape may peel off.

[0009] In addition, with the recent expansion of demand for electric vehicles and the like, there is a demand for smaller and more energy-efficient power storage devices. Therefore, the internal structure of the power storage device has also become complicated, the busbar has a more complicated shape, and is used in a narrow area. Moreover, when mass-produced busbars are used to manufacture power storage devices, a large number of busbars need to be transported. As a result, when the busbars are transported or used in a narrow area, the corners of the busbars sometimes come into contact with each other, and the insulating coating is damaged. In addition, since the corners of the busbars are easy to dissipate heat, the temperature of the corners of the busbar body is easy to change, and there is also a problem that the coating is easy to peel off due to the temperature difference.

[0010] The present invention is completed in view of the above-mentioned problems, and its purpose is to provide a busbar that can suppress the peeling of the insulating coating from the busbar body even when the busbars collide with each other or with other components, or due to repeated temperature changes. In addition, the present invention aims to provide a method for manufacturing a busbar, which can form an insulating coating with excellent strength on the busbar body in a desired area with a simple process even if the busbar body has a complex shape. In addition, the present invention aims to provide a power storage device that connects multiple battery cells or battery modules to each other through a busbar that suppresses the peeling of the insulating coating, and exhibits high safety even in abnormal situations.

[0011] Means for solving technical problems

[0012] The above-mentioned object of the present invention is achieved by the following [1] structure of the bus bar.

[0013] [1] A bus bar for use in an electric storage device including a battery cell, characterized in that:

[0014] The bus bar has:

[0015] a bus bar body having a pair of opposing main surface portions, a plurality of end surface portions connecting the pair of opposing main surface portions, and a corner portion located between the main surface portions and the end surface portions; and

[0016] an insulating film formed on a surface of the bus bar body,

[0017] The outer surface of the insulating coating formed at the corner of the bus bar body has a rounded shape.

[0018] The film thickness of the insulating film formed on the corner portion of the bus bar body is thicker than the film thickness of the insulating film formed on the main surface portion of the bus bar body.

[0019] In addition, preferred embodiments of the bus bar of the present invention relate to the following [2] to [5].

[0020] [2] In the bus bar of [1], it is characterized in that

[0021] The insulating coating is formed in an arc shape on the end surface portion when viewed in a cross section parallel to the plate thickness direction of the bus bar body and perpendicular to the end surface portion.

[0022] [3] In the bus bar of [1] or [2], the insulating coating has a thickness of 300 μm or more and 2000 μm or less at the corner.

[0023] [4] In the bus bar of [1] or [2], the bus bar body is a plate member that is Z-shaped or I-shaped as a whole.

[0024] [5] In the bus bar of [1] or [2], the bus bar body is characterized in that connection holes are formed at one end and the other end, and the surface of the bus bar body other than the connection holes is covered by the insulating film.

[0025] In addition, the above-mentioned object of the present invention is achieved by the following [6] structure of the power storage device.

[0026] [6] A power storage device characterized in that a plurality of battery cells or battery modules are connected via the bus bar according to any one of [1] to [5].

[0027] Utility Model Effect

[0028] According to the busbar of the utility model, the film thickness of the insulating film formed at the corner of the busbar body is thicker than the film thickness of the insulating film formed on the main surface, so even when the busbar is transported or used in a narrow area, it is possible to suppress the peeling of the insulating film at the corner. In addition, in the cross-sectional view of the busbar, the outer surface of the insulating film formed at the corner of the busbar body has a rounded shape, and the corner is not sharp, so even if flying debris collides with the outer surface of the insulating film, it is possible to suppress the insulating film from being damaged by the debris.

[0029] Furthermore, according to the power storage device of the utility model, since the battery cells or battery modules are connected by the bus bar which suppresses the occurrence of peeling of the insulating film, it is not easy to cause poor insulation, and the heat resistance is excellent, and it is highly safe even in abnormal conditions. In addition, even when the temperature of the corner of the bus bar body changes, the peeling of the insulating film can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is an exploded perspective view showing a state where the bus bar according to the embodiment of the present invention is attached to a battery cell.

[0031] Figure 2 Yes means Figure 1 A perspective view of a portion of a bus bar body in the bus bar is shown.

[0032] Figure 3 Yes Figure 1 The schematic diagram is an enlarged view of a part of the cross section of the bus bar as viewed along the AA arrow.

[0033] Figure 4 is to use the Figure 3A schematic diagram showing an enlarged view of a part of a cross section of a bus bar in the case of a bus bar body having a different shape.

[0034] Figure 5 It is a schematic diagram which shows the power storage device which concerns on embodiment of this invention.

[0035] Description of symbols

[0036] 10: Insulation coating;

[0037] 20: bus bar;

[0038] 25: busbar body;

[0039] 25a: main face;

[0040] 25b: end face;

[0041] 25c: corner;

[0042] 25d: bending part;

[0043] 26a, 26b: connecting holes;

[0044] 30: Central area;

[0045] 37: Corner measurement line;

[0046] 100: power storage device;

[0047] 110: battery unit;

[0048] 111: electrode;

[0049] 120: Battery casing. DETAILED DESCRIPTION

[0050] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the present invention is not limited to the embodiments described below, and can be implemented with arbitrary changes within the scope not departing from the gist of the present invention.

[0051] [Bus Bar]

[0052] Figure 1 2 is an exploded perspective view showing a state where the bus bar 20 according to the embodiment of the present utility model is mounted on the battery unit 110. Figure 1 As shown, the bus bar body 25 made of a conductive material is, for example, a metal plate-shaped member in a Z-shape as a whole, and the electrode 111 of the battery cell 110 is inserted into the connection hole 26a at one end and fixed by covering it with a terminal cap 112. In addition, the connection hole 26b at the other end of the bus bar body 25 is connected to an adjacent battery cell (not shown) and an external device (not shown).

[0053] Figure 2 Yes means Figure 1 A perspective view of a portion of a bus bar body in the bus bar is shown. Figure 3 Yes Figure 1 FIG. 1 is a schematic diagram showing an enlarged view of a portion of a cross section of a bus bar viewed along arrow AA. Figure 1 As shown, the bus bar 20 is, for example, a Z-shaped plate-shaped member. However, in this specification, the bus bar 20 is characterized by being in a flat plate shape except for the bent portion.

[0054] like Figure 2 As shown, the corner portion 25c of the busbar body 25 is a rectangle having an approximately right angle when viewed in cross section. In addition, the busbar body 25 has a pair of opposing main face portions 25a, a plurality of end face portions 25b connecting the main face portions 25a to each other, and a corner portion 25c located between the main face portions 25a and the end face portions 25b. That is, the main face portion 25a is a surface extending in a direction perpendicular to the plate thickness direction, and the end face portion 25b is a surface approximately parallel to the plate thickness direction. In addition, as shown in FIG. Figure 3 As shown, the bus bar 20 has an insulating coating 10 formed on the surface of a bus bar body 25 .

[0055] In this embodiment, if Figure 3 As shown in FIG. 1 , when the bus bar 20 is observed in a cross section parallel to the plate thickness direction of the bus bar body 25 and perpendicular to the end surface 25b, the outer surface of the insulating film 10 formed at the corner 25c has a rounded shape. In addition, at the end surface 25b, the insulating film 10 is formed in an arc shape. In addition, the film thickness of the insulating film 10 formed at the corner 25c of the bus bar body 25 is thicker than the film thickness of the insulating film 10 formed on the main surface 25a of the bus bar body 25.

[0056] The insulating film 10 having a rounded shape (also referred to as an R shape) on the outer surface means that even when the corner 25c of the bus bar body 25 is formed at a right angle in cross-sectional observation (when observed in cross section), the outer surface of the insulating film 10 is a flat surface. In addition, the insulating film 10 formed in an arc shape means that, in the above-mentioned cross-sectional observation of the end surface portion 25b, the film thickness becomes thicker as it approaches the center side rather than the corner 25c side.

[0057] Although not shown in the drawings, the bus bar body 25 may be formed in various shapes depending on the location where the battery unit 110 is installed, such as an overall I-shape or an indefinite shape having a bent portion.

[0058] The bus bar 20 configured as described above is applied to, for example, a power storage device 100 described later (see Figure 5), and are mounted on electric vehicles, etc., but in order to cope with the recent miniaturization of power storage devices and the high capacity of batteries, bus bars are used in narrow areas. In addition, when bus bars are mass-produced and transported, the bus bars are in contact with each other, especially at the corners, and the insulating film 10 is easily peeled off. In addition, when the power storage device is used, the temperature of the corner 25c of the bus bar body 25 is likely to change, and the insulating film 10 is also easily peeled off due to the temperature difference of the bus bar body 25.

[0059] In the present embodiment, the film thickness of the insulating film 10 formed at the corner portion 25c of the bus bar body 25 is thicker than the film thickness of the insulating film 10 formed at the main surface portion 25a of the bus bar body 25. Therefore, even when the bus bars 20 or the bus bars 20 contact with other components and the temperature changes, the insulating film 10 can be prevented from peeling off.

[0060] In addition, sometimes metal pieces of the battery cell 110 that has thermal runaway, film pieces of the insulating film in other busbars, fragments of the battery case 120, etc., may collide with the insulating film 10 on the surface of the busbar 20. In the present embodiment, the film thickness of the insulating film 10 formed at the corner 25c of the busbar body 25 is thicker than the film thickness at the main surface 25a, and the outer surface of the insulating film 10 formed at the corner 25c has a rounded shape. Therefore, even if flying fragments collide with the outer surface of the insulating film 10, the damage to the insulating film 10 due to the fragments can be minimized. Moreover, on the end surface 25b of the busbar body 25, the insulating film 10 is formed in an arc shape, and the fragments after the collision are reflected in an isotropic oblique direction, so that the impact of the busbar 20 due to the fragments can be alleviated.

[0061] In addition, if the bus bar body 25 is Figure 1 In the case of a bus bar 20 having a shape with a bent portion 25d and a curved portion (not shown) such as the Z-shaped shape shown in the figure, the operation becomes complicated in the method of winding the ceramic tape as in the bus bar of the above-mentioned Patent Document 1. Specifically, in order to avoid uneven winding or gaps in the bent portion 25d or the curved portion, the winding operation will take time. In addition, when the bus bar 20 is used, it is also conceivable that a gap will be generated between the bus bar body 25 and the tape due to vibration or the like, and the adhesive will be peeled off.

[0062] In contrast, in the present embodiment, the insulating coating 10 can be formed by coating the surface of the bus bar body 25 with an insulating paint. Therefore, the above-mentioned problem does not occur. As a method of coating the surface of the bus bar body 25 with an insulating paint, if "dip coating" is used, the manufacturing process of the bus bar can be simplified. In this way, the insulating coating 10 formed by coating the surface of the bus bar body 25 with an insulating paint and drying it is different from the insulating layer formed by winding a tape, etc., and can obtain excellent effects in terms of stripping and workability.

[0063] In addition, Figure 3 In the bus bar 20 shown in FIG. 1 , the corner 25 c of the bus bar body 25 is rectangular in cross-sectional view, but in the present invention, the cross-sectional shape of the corner 25 c is not particularly limited. Figure 4 As shown, the corner 25c of the bus bar body 25 may also have a rounded shape. In either case, as long as the film thickness of the insulating film 10 formed on the corner 25c of the bus bar body 25 is thicker than the film thickness of the insulating film 10 formed on the main surface 25a and the surface thereof has a rounded shape, the above-mentioned effect can be obtained.

[0064] (Film thickness at corners: 300 μm or more and 2000 μm or less)

[0065] If the thickness of the film formed at the corner 25c of the bus bar body 25 is too large, it is difficult to obtain the above-mentioned effect. Therefore, the thickness of the film formed at the corner 25c is preferably 2000 μm or less, more preferably 1500 μm or less, and further preferably 1000 μm or less. On the other hand, if the thickness of the film formed at the corner 25c is too small, it is difficult to ensure the insulation and heat resistance of the bus bar 20. Therefore, the thickness of the insulating film 10 formed at the corner 25c is preferably 300 μm or more, more preferably 400 μm or more, and further preferably 500 μm or more.

[0066] Here, the following reference Figure 2 to Figure 4 The following describes a method for measuring the thickness of the insulating coating 10 at the corner 20c and the thickness of the insulating coating 10 at the main surface 25a of the bus bar 20. When the bus bar 20 has a bent portion or a curved portion, the insulating coating 10 is cut near the bent portion or the curved portion and the thickness of the insulating coating 10 is measured as a rectangular flat plate.

[0067] When measuring the film thickness of the insulating film formed on the main surface, Figure 2 As shown in FIG. 1 , two pairs of corner portions 25c extending linearly around one of the main portions 25a of the pair of main portions of the busbar body 25 are divided into three equal parts, and the main portion 25a is divided into nine regions. In the present embodiment, the central region 30 (in the middle of the nine regions) is divided into nine regions. Figure 3 and Figure 4 The film thickness is measured at any three locations (indicated by thick lines in the figure), and the average value thereof is taken as the "film thickness Ts of the insulating film formed on the main surface". In addition, according to the above method, the main surface of the busbar body 25 is divided into 9 areas, but when measuring the film thickness of the insulating film 10, it is difficult to strictly divide the corner 25c into three equal parts because the busbar body 25 is not exposed. However, compared with the size of the busbar body 25, the thickness of the insulating film 10 is negligible, so in the state where the insulating film 10 is provided, it is sufficient to divide the two opposing corners 25c into roughly three equal parts.

[0068] When measuring the film thickness of the insulating film formed at the corner, first, the main surface 25a is cut along a line connecting the centers of at least one pair of the two pairs of corners 25c constituting the main surface 25a. Figure 3 or Figure 4 As shown, the film thickness of the insulating film at the corner is measured. Specifically, in the bus bar body 25, for example, extension lines 35 and 36 are drawn with respect to the main surface 25a and the end surface 25b constituting the corner 25c, respectively, and the bisector of the angle formed by the two extension lines 35 and 36 is set as the corner measurement line 37. Then, on the corner measurement line 37, the distance from the surface of the bus bar body 25 to the surface of the insulating film 10 is measured, and the average value thereof is taken as the "film thickness Tc of the insulating film formed at the corner".

[0069] In the bus bar of the present embodiment, the film thickness Tc of the insulating film 10 formed on the corner portion 25c of the bus bar body 25 is thicker than the film thickness Ts of the insulating film 10 formed on the main surface portion 25a, so that the above-mentioned effect can be obtained.

[0070] Furthermore, when there are a plurality of corners 25c, by adjusting the film thickness of each corner 25c and intentionally forming the thickest corner 25c, it is possible to suppress the occurrence of peeling of the insulation coating at the corners that particularly require strength among the plurality of corners 25c.

[0071] As described above, by making the thickness of the insulating film 10 at the corner 25c of the busbar body 25 thicker than the thickness of the insulating film 10 at the main surface 25a, it is possible to suppress the insulating film 10 from peeling off from the corner 25c when used or transported in a narrow place. Furthermore, the material of the insulating film 10 that can further improve the insulation and heat resistance is described below.

[0072] The insulating film 10 preferably contains a filler. The filler can improve the heat resistance. Inorganic compounds have a high melting point and are more heat resistant, so the insulating film 10 more preferably contains an inorganic compound as a filler, and more preferably contains a silicate compound. In this embodiment, as described later, the insulating film 10 preferably contains an organic silicon material as a binder. The organic silicon material can be converted into SiO2 by thermal decomposition, so if the insulating film 10 contains a silicate compound having the same components as SiO2 as an inorganic compound, the bonding strength between the inorganic compound and the binder can be improved. If the material of the insulating film 10 is selected in this way, the heat resistance and fire resistance of the insulating film 10 can be further improved. Therefore, when the bus bar 20 (refer to Figure 3 ) When used in the power storage device 100, the bus bar 20 can be protected from the high temperature and flame of the battery cell 110 that has thermal runaway. In addition, the thermal runaway can be prevented from being chained to the adjacent battery cell 110 via the bus bar 20.

[0073] The inorganic compound preferably contains at least one selected from silica, alumina, mullite and zirconia. These compounds have a melting point higher than the assumed heat exposure temperature of the metal material generally used for the busbar body and have high insulation properties, so they can be suitably used as the material of the insulating film 10.

[0074] Furthermore, as the inorganic compound, it is also preferred that at least one selected from the group consisting of glass-based materials, mica, kaolin, talc, clay, pyrophyllite, montmorillonite, bentonite, wollastonite, xonotlite, zeolite, diatomaceous earth, and halloysite be contained.

[0075] Furthermore, the inorganic compound is preferably at least one selected from the group consisting of flaky, fibrous, and granular. Among them, flaky glass in particular exhibits excellent insulation and heat resistance by being planarly oriented in the coating. Therefore, it is particularly preferred to include flaky glass as the inorganic compound. In addition, the above-mentioned mica is also preferably used for the same reasons as for the flaky glass.

[0076] The content of the filler in the insulating film 10 relative to the total components is preferably 3 volume % to 70 volume %, more preferably 10 volume % to 60 volume %, and further preferably 20 volume % to 50 volume %. When the content of the filler is less than 3 volume %, it may not be possible to obtain sufficient insulation and heat resistance. As described later, the insulating film 10 is formed by "dip coating", but if the content of the filler exceeds 70 volume %, the viscosity of the insulating coating for dipping becomes too high, and the film forming property will deteriorate.

[0077] In addition, the insulating film 10 preferably contains a silicone material as a binder because of its excellent non-flammability and heat resistance. Examples of the silicone material include silicone resins, and the thickness of the insulating film 10 can be easily controlled by using a thixotropic agent as a thickener.

[0078] Furthermore, the insulating film 10 may contain other materials such as a flame retardant, a dispersant, and a pigment in addition to the above-mentioned filler and silicone-based material within a range that does not affect the insulating properties and heat resistance.

[0079] [Bus bar manufacturing method]

[0080] In the present invention, the method for manufacturing the bus bar is not particularly limited. As a method for coating the bus bar body 25 with insulating coating, various methods such as dipping coating, spraying, coating with a brush, etc., and powder coating can be used. Among these coating methods, dipping coating is preferably used as a process for manufacturing the bus bar from the perspective of ease of operation. Figure 1 An example of a method for manufacturing a bus bar using dip coating will be described.

[0081] (Bus bar body and insulating paint preparation process)

[0082] First, prepare the bus bar body 25 and the insulating coating. Figure 2 As shown, the busbar body 25 has a pair of opposing main face portions 25a, a plurality of end face portions 25b connecting the opposing main face portions 25a, and corner portions 25c located between the main face portions 25a and the end face portions 25b. The insulating coating is prepared by adding a predetermined amount of filler to a silicone resin and mixing the mixture thoroughly.

[0083] (Covering process)

[0084] Next, after masking the peripheries of the connection holes 26a and 26b of the bus bar body 25, the surface of the bus bar body 25 is covered with insulating paint. In the present embodiment, the insulating paint is applied to a desired area of ​​the surface of the bus bar body 25 by immersing the bus bar body 25 in the insulating paint and then lifting it from the insulating paint.

[0085] (Drying process)

[0086] Then, the insulating coating material covering the surface of the bus bar body 25 is dried and cured to form the insulating coating 10 .

[0087] In the present embodiment, the film thickness of the insulating film 10 at the corner 25c of the bus bar body 25 needs to be thicker than the film thickness of the insulating film 10 at the main surface 25a. As a method for this, the following method can be used: in the above-mentioned coating step, after the bus bar body 25 is immersed in the insulating paint, the bus bar body 25 is lifted from the insulating paint in a state where the corner 25c or the end surface 25b of the bus bar body 25 is directed vertically downward. However, there is no particular limitation on the method for making the film thickness of the insulating film 10 at the corner 25c of the bus bar body 25 thicker than the film thickness of the insulating film 10 at the main surface 25a.

[0088] In addition, as a method of forming the insulating film 10 on the surface of the bus bar body 25, when spraying, coating with a brush or the like, powder coating, etc. are used, it is sufficient to focus on the corners 25c of the bus bar body 25. In this way, the insulating film obtained by spraying, coating with a brush or the like, powder coating, etc. can also be called "insulating coating film".

[0089] The amount of insulating paint applied may be adjusted by appropriately adjusting the pulling speed, drying temperature, etc. Specifically, the insulating paint is applied so that the film thickness of the insulating film 10 at the corner 25c of the bus bar body 25 after drying is 300 μm or more, preferably 400 μm or more, and more preferably 500 μm or more. In addition, the insulating paint is applied so that the film thickness of the insulating film 10 at the corner 25c of the bus bar body 25 after drying is 2000 μm or less, preferably 1500 μm or less, and more preferably 1000 μm or less.

[0090] In addition, the content of filler in the insulating coating relative to the total solid content is preferably 3 volume % to 70 volume %, more preferably 10 volume % to 60 volume %, and further preferably 20 volume % to 50 volume %. As mentioned above, when the content of filler is less than 3 volume %, it is possible that insulation and heat resistance cannot be fully obtained. On the other hand, when the content of filler exceeds 70 volume %, the viscosity of the insulating coating becomes too high and the film-forming property may be reduced.

[0091] If the busbar body 25 is Figure 1 If the bus bar has a shape with a bent portion 25d or a curved portion (not shown) such as the Z-shaped shape shown in the figure, the work efficiency will be reduced in the method of winding the ceramic tape as in the bus bar of the above-mentioned patent document 1. Specifically, in order to avoid uneven winding or gaps in the bent portion 25d or the curved portion, the winding operation may be laborious. In addition, it is assumed that when the bus bar is used, a gap is generated between the bus bar body and the tape due to vibration, etc., or the adhesive is peeled off.

[0092] In contrast, in the present embodiment, for example, according to the manufacturing method of the bus bar using dip coating, the bus bar body 25 is dipped in the insulating coating, lifted up, and then dried to form the insulating coating 10, so that the bus bar can be manufactured in a simple process. Therefore, the manufacturing cost can also be reduced.

[0093] [Electricity storage device]

[0094] Figure 5 Schematic diagram of a power storage device according to an embodiment of the present invention. Figure 5 As shown, the power storage device 100 houses a plurality of battery cells 110 in a battery case 120. The adjacent battery cells 110 are connected to each other by the bus bar 20, and the electrodes are covered with terminal caps 112.

[0095] The bus bar 20 is a structure in which the bus bar body 25 is covered with the above-mentioned insulating film 10, and even if a certain battery cell 110 has a thermal runaway, the bus bar 20 can be protected, and the thermal runaway can be prevented from being chained to the adjacent battery cell 110 via the bus bar 20. Therefore, the power storage device of this embodiment has high safety even in the event of an abnormality because a plurality of battery cells 110 and a battery module (not shown) are connected by such a bus bar 20.

[0096] Above, various embodiments are described with reference to the accompanying drawings, but the present invention is certainly not limited to such examples. It is clear to those skilled in the art that various variations or modifications can be thought of within the scope described in the application documents, and it should be understood that they will naturally fall within the technical scope of the present invention. In addition, within the scope of not departing from the gist of the utility model, the various constituent elements in the above-mentioned embodiments may also be arbitrarily combined.

[0097] In addition, this application is an application based on the Japanese patent application (Japanese Patent Application No. 2023-070353) filed on April 21, 2023, and the contents thereof are incorporated herein by reference.

Claims

1. A bus bar for a power storage device including a battery cell, characterized in that: The bus bar has: A busbar body having a pair of opposing main surface portions, a plurality of end surface portions connecting the pair of opposing main surface portions, and a corner portion located between the main surface portions and the end surface portions; as well as an insulating film formed on a surface of the bus bar body, The outer surface of the insulating coating formed at the corner of the bus bar body has a rounded shape. The film thickness of the insulating film formed on the corner portion of the bus bar body is thicker than the film thickness of the insulating film formed on the main surface portion of the bus bar body.

2. The bus bar according to claim 1, characterized in that: The insulating coating is formed in an arc shape on the end surface portion when viewed in a cross section parallel to the plate thickness direction of the bus bar body and perpendicular to the end surface portion.

3. The bus bar according to claim 1 or 2, characterized in that: The film thickness of the insulating film at the corner portion is greater than or equal to 300 μm and less than or equal to 2000 μm.

4. The bus bar according to claim 1 or 2, characterized in that: The bus bar main body is a plate member having a Z-shape or an I-shape as a whole.

5. The bus bar according to claim 1 or 2, characterized in that: The bus bar body has connection holes formed at one end and the other end, and a surface of a portion of the bus bar body other than the connection holes is covered with the insulating film.

6. A power storage device, characterized in that: A plurality of battery cells or battery modules are connected by the bus bar according to any one of claims 1 to 5.

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