Method for manufacturing laminated battery and laminated battery

Abstract

The present disclosure relates to a method for manufacturing a laminated battery and a laminated battery, and provides a method for manufacturing a laminated battery capable of suppressing the occurrence of a thickness difference according to the difference in locations in a deposited laminated film in contact with a side member. Provided is a method for manufacturing a laminated battery, the laminated battery being provided with: an electrode body; a side surface member disposed on a side surface of the electrode body; provided is a method for manufacturing a laminated battery, the method comprising a step for depositing a laminated film so as to cover a part of a side surface member and an electrode body, the laminated film covering the electrode body and a part of the side surface member, the side surface member being disposed at a position offset to one side from the center of the side surface in the longitudinal direction of the side surface, the method comprising a step for depositing the laminated film so as to cover the electrode body and the part of the side surface member, the side surface member has a shape in which the thickness continuously increases toward the side in which the side surface member is disposed in a biased manner.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a laminated battery and a laminated battery. Background Art

[0002] Conventionally, a laminated battery is used which includes an electrode body, side members such as terminals, and a laminate film covering a portion of the side members and the electrode body. In addition, in the laminated battery, the side member is sometimes arranged at a position offset to one side relative to the center of the side in the long side direction of the side.

[0003] For example, Japanese Patent Application Laid-Open No. 11-283611 discloses a battery in which a terminal on one side surface of the battery is arranged offset to one side with respect to the center of the side surface.

[0004] However, when the laminate film is welded to the electrode body in which the side member is arranged biased to one side, a thickness difference may occur in the laminate film in the region in contact with the side member depending on the location. Summary of the invention

[0005] The present disclosure provides a method for manufacturing a laminated battery capable of suppressing a thickness difference due to a location in a laminated film in contact with a side member after welding, and a laminated battery capable of suppressing a thickness difference due to a location in a laminated film in contact with a side member.

[0006] The present disclosure includes the following aspects.

[0007] A first aspect of the present disclosure provides a method for manufacturing a laminated battery, the laminated battery comprising:

[0008] Electrode body;

[0009] a side member disposed on a side surface of the electrode body; and

[0010] a laminate film covering a portion of the side member and the electrode body,

[0011] The side member is arranged at a position biased toward a first side in the long-side direction relative to the center of the side surface in the long-side direction of the side surface, wherein:

[0012] The method for manufacturing a laminated battery includes the step of welding the laminate film so as to cover a part of the side member and the electrode body.

[0013] The side member has a shape in which the thickness of the side surface in the short-side direction becomes continuously thicker toward the first side.

[0014] Based on the first aspect, in a second aspect of the present disclosure,

[0015] The side surface has a first area and a second area, the first area being an area located on the first side relative to the side member and not provided with the side member, and the second area being an area located on a second side opposite to the first side relative to the side member and not provided with the side member,

[0016] The area of ​​the first region is smaller than the area of ​​the second region,

[0017] In the side member, a contact area between the side member and the electrode body is larger in a region close to the first region than in a region close to the second region, with the center of the side member in the longitudinal direction as a boundary.

[0018] A third aspect of the present disclosure provides a laminated battery, the laminated battery comprising:

[0019] Electrode body;

[0020] a side member disposed on a side surface of the electrode body; and

[0021] a laminate film covering a portion of the side member and the electrode body,

[0022] The side member is arranged at a position deviated toward a first side in the long-side direction relative to the center of the side surface in the long-side direction of the side surface,

[0023] The side member has a shape in which the thickness of the side surface in the short-side direction becomes continuously thicker toward the first side.

[0024] Based on the third aspect, in a fourth aspect of the present disclosure,

[0025] The side surface has a first area and a second area, the first area being an area located on the first side relative to the side member and not provided with the side member, and the second area being an area located on a second side opposite to the first side relative to the side member and not provided with the side member,

[0026] The area of ​​the first region is smaller than the area of ​​the second region,

[0027] In the side member, a contact area between the side member and the electrode body is larger in a region close to the first region than in a region close to the second region, with the center of the side member in the longitudinal direction as a boundary.

[0028] According to the present disclosure, a method for manufacturing a laminated battery capable of suppressing thickness differences due to locations in a laminated film after welding connected to a side member, and a laminated battery capable of suppressing thickness differences due to locations in a laminated film connected to a side member can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic perspective view showing a laminated battery manufactured by the method for manufacturing a laminated battery according to an embodiment of the present disclosure, and an electrode body and a side member included in the laminated battery according to an embodiment of the present disclosure.

[0030] Figure 2 This is a schematic side view of a laminated battery manufactured by a method for manufacturing a laminated battery according to an embodiment of the present disclosure and a laminated battery according to an embodiment of the present disclosure, as viewed from a side direction.

[0031] Figure 3 It is a schematic plan view showing the main parts of the vehicle.

[0032] Figure 4 This is a schematic perspective view of a battery module.

[0033] Figure 5 This is a plan view of the battery module with the upper cover removed.

[0034] Figure 6 This is a schematic diagram of a battery cell housed in a battery module as viewed from the thickness direction. DETAILED DESCRIPTION

[0035] An embodiment as an example of the present disclosure will be described. These descriptions illustrate the embodiment and do not limit the scope of the invention.

[0036] Furthermore, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process can be achieved.

[0037] <Method for manufacturing laminated battery and laminated battery>

[0038] The manufacturing method of a laminated battery of an embodiment of the present disclosure relates to the following manufacturing method of a laminated battery, wherein the laminated battery comprises: an electrode body; a side member, the side member is arranged on the side of the electrode body; and a laminate film, the laminate film covers a portion of the side member and the electrode body, and the side member is arranged at a position biased to one side relative to the center of the side in the long side direction of the side.

[0039] This manufacturing method includes a step of welding a laminate film so as to cover a part of the side member and the electrode body.

[0040] Furthermore, the side member has a shape in which the thickness continuously increases toward the side where the side member is disposed in an offset manner.

[0041] The laminated battery of the embodiment of the present disclosure comprises: an electrode body; a side member arranged on the side of the electrode body; and a laminate film, the laminate film covering a portion of the side member and the electrode body, the side member being arranged at a position offset to one side relative to the center of the side in the long side direction of the side.

[0042] Furthermore, the side member has a shape in which the thickness continuously increases toward the side where the side member is disposed in an offset manner.

[0043] Here, a laminated battery manufactured by a method for manufacturing a laminated battery according to an embodiment of the present disclosure and a laminated battery according to an embodiment of the present disclosure will be described using the drawings.

[0044] Each of the drawings shown below is a schematic diagram, and the size and shape of each part are exaggerated as appropriate for easy understanding.

[0045] Figure 1 It is a schematic perspective view showing a laminated battery manufactured by the method for manufacturing a laminated battery according to an embodiment of the present disclosure, and an electrode body and a side member included in the laminated battery according to an embodiment of the present disclosure. Figure 2 From the side direction (the direction of the surface where the side member is arranged, Figure 1 and Figure 2 A schematic side view of a laminated battery manufactured by a method for manufacturing a laminated battery according to an embodiment of the present disclosure and a laminated battery according to an embodiment of the present disclosure, as viewed in the Z direction.

[0046] Figure 1 and Figure 2 The battery (battery cell) 20 shown as an example of a laminated battery includes an electrode body 4 and terminals 26 as an example of side members respectively arranged on a pair of side surfaces 4A of the electrode body 4. In addition, on the side surface 4A of the electrode body 4, there are two areas 41A and 42A where the terminals 26 are not arranged on both sides in the long side direction (arrow X direction) of the side surface 4A.

[0047] One side of the side surface 4A in the long-side direction is defined as the first side, and the other side is defined as the second side. The terminal 26 is disposed at a position offset to the first side (at the position of the center Lc of the side surface 4A) in the long-side direction (arrow X direction) of the side surface 4A of the electrode body 4. Figure 1 and Figure 2 Therefore, in the side surface 4A of the electrode body 4 , the area of ​​the region 42A on the first side (an example of the first region) is smaller than the area of ​​the region 41A on the second side (an example of the second region).

[0048] In the following, of the two regions where no side member is arranged on the side surface of the electrode body, the region with a wider area is referred to as a “wide width region”, and the region with a narrower area is referred to as a “narrow width region”.

[0049] In addition, if Figure 2 As shown, the battery (battery cell) 20 includes a laminate film 28 covering a portion of the terminal 26 and the electrode body 4. The laminate film 28 covers the entire surface of the electrode body 4, and the area of ​​the side surface 4A of the electrode body 4 where the terminal 26 is not provided is completely covered by the laminate film 28 (therefore, in Figure 2 2 shows the electrode body 4 covered by the laminate film 28 with a dotted line. In addition, the laminate film 28 is arranged relative to the terminal 26 so as to cover a portion of each of the upper surface 26B, the left side 26C, the lower surface 26D, and the right side 26E of the terminal 26, and more specifically, is arranged so as to cover the region on the electrode body 4 side of these four surfaces. Therefore, the entire surface of the outer side surface 26A of the terminal 26 and the region on the opposite side of the upper surface 26B, the left side 26C, the lower surface 26D, and the right side 26E are not covered by the laminate film 28 and are exposed.

[0050] Furthermore, the terminal 26 has a short side direction (eg, Figure 1 and Figure 2 That is, the thickness of the terminal 26 continuously increases from the region 41A (wide region) side of the wider area of ​​the two regions 41A and 42A in the side surface 4A of the electrode body 4 where the terminal 26 is not configured toward the region 42A (narrow region) side of the narrower area, the thickness of the terminal 26 continuously increases.

[0051] Conventionally, a laminated battery is used which includes an electrode body, side members such as terminals, and a laminate film covering a portion of the side members and the electrode body. In addition, in the laminated battery, due to the arrangement of the batteries in the battery module, the side members may be arranged in the longitudinal direction of the side (in the longitudinal direction of the side). Figure 1 and Figure 2 The center of the side surface is arranged at a position biased toward the first side (in the X direction).

[0052] Here, in the manufacture of a laminated battery, when a part of the side member and the electrode body are sealed with a laminate film, a process of welding the laminate film in a manner covering a part of the side member and the electrode body is performed. For example, at a portion where the laminate film and the side member are in contact, a heated welding member is pressed against the side member via the laminate film, thereby melting the inner side (the side in contact with the side member) of the laminate film, and welding the laminate film to the side member.

[0053] However, when the laminated film is welded to the electrode body in which the side member is arranged with the side biased toward the first side, the thickness difference may occur in the laminated film in the area in contact with the side member depending on the location. Specifically, in the laminated film in the area in contact with the side member, the thickness of the laminated film becomes thinner in the area close to the first side. That is, in the laminated film in the area in contact with the side member, the thickness of the laminated film becomes thinner in the area close to the first side on the side of the electrode body (in the area close to the first side). Figure 1 and Figure 2 The thickness of the laminate film is thinner in the region where the laminate film is in contact with the side member (the region 42A side). On the other hand, in the region where the laminate film is in contact with the side member, the thickness of the laminate film is thicker in the region close to the second side opposite to the first side. That is, in the region where the laminate film is in contact with the side member, the thickness of the laminate film is thicker in the region close to the wide region side of the electrode body (the region 42A side). Figure 1 and Figure 2 In the region (region 41A side), the thickness of the laminate film becomes thicker.

[0054] The reason is presumably as follows.

[0055] Here, a case where the side member is arranged on the side of the electrode body with a bias toward the first side and the shape of the side member is a rectangular parallelepiped (that is, the thickness does not change toward the first side and is a shape with a constant thickness) is described. Since the heat applied to the laminated film when the laminated film is melted onto the side member will also be absorbed by the side member and the electrode body, not all of the applied heat contributes to the melting of the inner surface of the laminated film. Furthermore, in an electrode body in which the side member is arranged on the side of the electrode body with a bias toward the first side, it can be considered that in the long side direction (in the Figure 1 and Figure 2 There will be a difference in the amount of heat absorbed by the electrode body on the first side and the second side of the side member on the side of the electrode body (in the X direction). That is, it can be considered that, on the side of the electrode body, the amount of heat absorbed by the electrode body during the welding of the laminate film increases on the side member on the side closer to the wide area, and the amount of heat absorbed by the electrode body decreases on the side member on the side closer to the narrow area. It is speculated that this is because the volume of the electrode body that contributes to heat absorption on the wide area side (i.e., the volume of the electrode body that exists near the side member on the wide area side) is larger than the volume of the electrode body that contributes to heat absorption on the narrow area side (i.e., the volume of the electrode body that exists near the side member on the narrow area side). Furthermore, on the side closer to the wide area ( Figure 1 and Figure 2 In the laminated film that is in contact with the side member of the electrode body (left side in the figure), the heat absorption of the electrode body is large, so the heat contributing to the melting of the inner surface of the laminated film becomes smaller, and the amount of melting decreases, so the thickness of the laminated film after welding becomes thicker. On the other hand, in the laminated film that is in contact with the narrow area side (on the left side in the figure), the heat absorption of the electrode body is large, so the heat contributing to the melting of the inner surface of the laminated film becomes smaller, and the amount of melting decreases, so the thickness of the laminated film after welding becomes thicker. Figure 1 and Figure 2In the laminated film in contact with the side member (right side in the figure), since the amount of heat absorbed by the electrode body is small, the heat contributing to the melting of the inner surface of the laminated film becomes larger, and the amount of melting increases, so the thickness of the laminated film after welding becomes thinner. Based on the above mechanism, it can be inferred that in the laminated film after welding in the area in contact with the side member, a thickness difference will occur depending on the location.

[0056] Therefore, in the manufacturing method of the laminated battery and the laminated battery of the embodiment of the present disclosure, the shape of the side member disposed toward the first side is set to a shape whose thickness continuously increases toward the first side. That is, the shape of the side member is set to increase from the wide area side toward the narrow area side ( Figure 1 and Figure 2 Thus, the wide area side (on the right side) is made thicker. Figure 1 and Figure 2 The volume of the side member itself is reduced, and the contact area between the side member and the electrode body is also reduced. On the other hand, the narrow area side (on the left side) is Figure 1 and Figure 2 The volume of the side member itself (right side in the figure) increases, and the area of ​​the contact surface between the side member and the electrode body also increases. That is, in the side member, the center of the side member in the long side direction of the side of the electrode body is used as the boundary, and the contact area between the side member and the electrode body in the area close to the narrow area is increased compared with the area close to the wide area. Therefore, in the laminated film connected to the side member on the wide area side, the heat absorption of the side member and the heat absorption of the electrode body can be reduced. In addition, in the laminated film connected to the side member on the narrow area side, the heat absorption of the side member and the heat absorption of the electrode body can be increased. As a result, in the laminated film connected to the side member on the wide area side and the laminated film connected to the side member on the narrow area side, the heat that helps the melting of the inner surface of the laminated film during welding can be uniformized. In addition, it is possible to suppress the thickness difference caused by different parts in the laminated film after welding in the area connected to the side member.

[0057] Next, a laminated battery manufactured by a method for manufacturing a laminated battery according to an embodiment of the present disclosure, and a battery module, a battery pack, and a vehicle including the laminated battery according to an embodiment of the present disclosure will be described using the drawings.

[0058] (Overall Structure of Vehicle 100)

[0059] Figure 3 1 is a schematic plan view showing the main parts of a vehicle 100 to which the battery pack 10 according to the embodiment is applied. Figure 3As shown, the vehicle 100 is an electric vehicle (BEV) equipped with a battery pack 10 under the floor. In addition, the arrow UP, arrow FR, and arrow LH in each figure respectively indicate the upper side in the vehicle vertical direction, the front side in the vehicle front-rear direction, and the left side in the vehicle width direction. In the following description, when the front-rear, left-right, and up-down directions are used for description, unless otherwise specified, the front-rear direction in the vehicle front-rear direction, the left-right direction in the vehicle width direction, and the up-down direction in the vehicle vertical direction are indicated.

[0060] As an example, the vehicle 100 of the present embodiment is provided with a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 at a position closer to the front side of the vehicle than the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are provided at a position closer to the rear side of the vehicle than the battery pack 10.

[0061] The DC current output from battery pack 10 is supplied to electric compressor 104, PTC heater 106, inverter 112, etc. after the voltage is adjusted by DC / DC converter 102. In addition, by supplying power to motor 108 via inverter 112, rear wheels are rotated and vehicle 100 travels.

[0062] A charging port 116 is provided on the right side of the rear portion of the vehicle 100 . By connecting a charging plug of an external charging device (not shown) to the charging port 116 , electric power can be stored in the battery pack 10 via the charger 114 .

[0063] In addition, the configuration and structure of each component constituting the vehicle 100 are not limited to the above structure. For example, it can also be applied to a hybrid vehicle (HV: Hybrid Vehicle) or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle) equipped with an engine. In addition, in the present embodiment, a rear-wheel drive vehicle is provided in which the motor 108 is mounted at the rear of the vehicle, but it is not limited to this. It can be provided as a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 can be mounted at the front and rear of the vehicle. Moreover, it can also be a vehicle with an in-wheel motor in each wheel.

[0064] Here, the battery pack 10 is configured to include a plurality of battery modules 11. In the present embodiment, as an example, 10 battery modules 11 are provided. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 along the vehicle front-rear direction, and five battery modules 11 are arranged on the left side of the vehicle 100 along the vehicle front-rear direction. In addition, each battery module 11 is electrically connected.

[0065] Figure 4 1 is a schematic three-dimensional diagram of the battery module 11. Figure 4 As shown, the battery module 11 is formed into a substantially rectangular parallelepiped shape with the vehicle width direction as the long side direction. In addition, the outer shell of the battery module 11 is formed of an aluminum alloy. For example, an aluminum die casting is joined to both ends of an aluminum alloy extrusion by laser welding or the like, thereby forming the outer shell of the battery module 11.

[0066] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 22 described later is connected to the connector 14. Bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0067] The battery module 11 has a length MW in the vehicle width direction of, for example, 350 mm to 600 mm, a length ML in the vehicle front-rear direction of, for example, 150 mm to 250 mm, and a height MH in the vehicle up-down direction of, for example, 80 mm to 110 mm.

[0068] Figure 5 FIG. 1 is a plan view of the battery module 11 after the upper cover is removed. Figure 5 As shown, a plurality of battery cells 20 are housed in an aligned state inside the battery module 11. In the present embodiment, as an example, 24 battery cells 20 are aligned in the vehicle front-rear direction and bonded to each other.

[0069] A flexible printed circuit (FPC) 22 is disposed on the battery cell 20. The flexible printed circuit 22 is formed in a strip shape with the vehicle width direction as the long side direction, and thermistors 24 are provided at both ends of the flexible printed circuit 22. The thermistor 24 is not bonded to the battery cell 20, but is pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0070] In addition, one or more buffers (not shown) are accommodated inside the battery module 11. For example, the buffer is a thin plate-shaped member that can be elastically deformed, and is arranged between adjacent battery cells 20 with the arrangement direction of the battery cells 20 as the thickness direction. In this embodiment, as an example, buffers are arranged at both ends and the center of the battery module 11 in the long side direction.

[0071] Figure 6 2 is a schematic diagram of a battery cell 20 housed in a battery module 11 as viewed from the thickness direction. Figure 6 As shown, the battery cell 20 is formed in a substantially rectangular plate shape, and an electrode body (not shown) is accommodated therein. The electrode body is formed by laminating a positive electrode, a negative electrode, and a separator, and is sealed by a laminate film 28 .

[0072] In this embodiment, as an example, the electrode body receiving portion is formed by folding and laminating the embossed sheet-shaped laminate film 28. In addition, both a single cup embossing structure in which embossing is performed at one location and a double cup embossing structure in which embossing is performed at two locations can be used, but in this embodiment, a single cup embossing structure with a drawing depth of about 8 mm to 10 mm is used.

[0073] The upper ends of both ends of the battery cell 20 in the longitudinal direction are bent, and the corners form an outer shape. In addition, the upper end of the battery cell 20 is bent, and the fixing band 30 is wound around the upper end of the battery cell 20 along the longitudinal direction.

[0074] Here, terminals (tabs) 26 are provided at both ends of the battery cell 20 in the longitudinal direction. In the present embodiment, as an example, the terminals 26 are provided at positions offset downward from the vertical center of the battery cell 20. The terminals 26 are joined to bus bars (not shown) by laser welding or the like.

[0075] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 mm to 900 mm, or 1000 mm or more, the length CW2 of the region where the electrode body is housed is, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 mm to 900 mm, or 1000 mm or more, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm, 110 mm to 140 mm. In addition, the thickness of the battery cell 20 is 5.0 mm to 7.0 mm, 7.0 mm to 9.0 mm, or 9.0 mm to 11.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm, 50 mm to 60 mm, or 60 mm to 70 mm.

Claims

1. A method for manufacturing a laminated battery, the laminated battery comprising: Electrode body; a side member, the side member being arranged on a side surface of the electrode body; and a laminate film covering a portion of the side member and the electrode body, The side member is arranged at a position biased toward a first side in the long-side direction relative to the center of the side surface in the long-side direction of the side surface, wherein: The method for manufacturing a laminated battery includes the step of welding the laminate film so as to cover a part of the side member and the electrode body. The side member has a shape in which the thickness of the side surface in the short-side direction becomes continuously thicker toward the first side.

2. The method for manufacturing a laminated battery according to claim 1, wherein: The side surface has a first area and a second area, the first area being an area located on the first side relative to the side member and not provided with the side member, and the second area being an area located on a second side opposite to the first side relative to the side member and not provided with the side member, The area of ​​the first region is smaller than the area of ​​the second region, In the side member, a contact area between the side member and the electrode body is larger in a region close to the first region than in a region close to the second region, with the center of the side member in the longitudinal direction as a boundary.

3. A laminated battery, comprising: Electrode body; a side member, the side member being arranged on a side surface of the electrode body; and a laminate film covering a portion of the side member and the electrode body, The side member is arranged at a position deviated toward a first side in the long-side direction relative to the center of the side surface in the long-side direction of the side surface, The side member has a shape in which the thickness of the side surface in the short-side direction becomes continuously thicker toward the first side.

4. The laminated battery according to claim 3, wherein The side surface has a first area and a second area, the first area being an area located on the first side relative to the side member and not provided with the side member, and the second area being an area located on a second side opposite to the first side relative to the side member and not provided with the side member, The area of ​​the first region is smaller than the area of ​​the second region, In the side member, a contact area between the side member and the electrode body is larger in a region close to the first region than in a region close to the second region, with the center of the side member in the longitudinal direction as a boundary.

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