Battery pack and method for manufacturing same

Abstract

This battery pack includes: a secondary battery cell including a cell first main surface, a cell second main surface facing the cell first main surface, and a pair of cell side surfaces connecting the cell first main surface and the cell second main surface; a resin frame including a pair of frame wall parts covering at least the pair of cell side surfaces of the secondary battery cell; a metal first plate part connected to the frame by a first connection structure and fixed to the cell first main surface of the secondary battery cell via a first adhesive body; and a metal second plate part connected to the frame by a second connection structure and fixed to the cell second main surface of the secondary battery cell via a fixing means. The second connection structure is configured to allow the second plate part to be displaced in a direction away from the first plate part between the pair of frame wall parts in a state in which the secondary battery cell is swollen.

Description

Battery pack and manufacturing method thereof

[0001] The present disclosure relates to a battery pack and a method for manufacturing the same.

[0002] Battery packs containing rechargeable secondary battery cells such as lithium-ion secondary batteries are used in a variety of applications as power sources for driving devices (see, for example, Patent Document 1). It is known that lithium-ion batteries in such battery packs expand when they are charged or discharged.

[0003] However, the expansion may cause the battery pack to look unattractive or may cause problems in the connection between the terminals of the secondary battery cells and the terminals of the battery pack.

[0004] Patent No. 3851277

[0005] One object of the present disclosure is to provide a battery pack and a manufacturing method thereof that can be used reliably even if secondary battery cells swell. Another object is to provide a battery pack and a manufacturing method thereof that makes the deterioration of appearance due to secondary battery cell swelling less noticeable. Note that the description of these objects and objects of the present disclosure does not preclude the existence of other objects and objects. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these objects. Furthermore, other objects can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0006] A battery pack according to one embodiment of the present disclosure includes a secondary battery cell having a first cell main surface, a second cell main surface opposite the first cell main surface, and a pair of cell side surfaces connected to the first cell main surface and the second cell main surface; a resin frame body having a pair of frame wall portions covering at least the pair of cell side surfaces of the secondary battery cell; a first metal plate portion connected to the frame body by a first connecting structure and fixed to the first cell main surface of the secondary battery cell via a first adhesive; and a second metal plate portion connected to the frame body by a second connecting structure and fixed to the second cell main surface of the secondary battery cell via a fixing means, wherein the second connecting structure is configured to allow the second plate portion to be displaced between the pair of frame wall portions in a direction away from the first plate portion when the secondary battery cell is expanded.

[0007] Another embodiment of a manufacturing method for a battery pack includes: a secondary battery cell having a first cell main surface, a second cell main surface opposite the first cell main surface, and a pair of cell side surfaces connecting the first cell main surface and the second cell main surface; a resin frame body having a pair of frame wall portions covering at least the pair of cell side surfaces of the secondary battery cell; a first metal plate portion fixed to the frame body and covering the first cell main surface of the secondary battery cell; and a second metal plate portion fixed to the frame body and covering the second cell main surface of the secondary battery cell, the manufacturing method for a battery pack including the steps of: sliding the first plate portion between the pair of frame wall portions of the frame body to connect the frame body and the first plate portion; inserting the secondary battery cell between the pair of frame wall portions of the frame body to fix the first cell main surface of the secondary battery cell to the first plate portion via a first adhesive; and fixing the second plate portion to the second cell main surface of the secondary battery cell via a fixing means.

[0008] In a battery pack according to one embodiment of the present disclosure, the first plate portion is fixed to the first surface of the secondary battery cell and also to the frame body, while the second plate portion is not fixed to the frame body. As a result, even if the secondary battery cell expands and the thickness between the pair of side surfaces increases, deformation can be tolerated by displacing the second plate portion side accordingly.

[0009] 1. A perspective view showing a battery pack according to a first embodiment. 1. A perspective view of the battery pack of FIG. 1, seen from diagonally below. 2. An exploded perspective view of the battery pack of FIG. 1. 3. A cross-sectional perspective view of the battery pack of FIG. 1, taken along line IV-IV. 4. An enlarged rear perspective view of the battery pack of FIG. 1. 5. An exploded perspective view of the battery pack of FIG. 5. 6. An exploded perspective view of the battery pack of FIG. 5, seen from diagonally below. 7. An exploded perspective view of the battery pack of FIG. 7, seen from diagonally below. 8. An exploded perspective view of the battery pack of FIG. 7, seen from diagonally below. 9. An exploded perspective view of the battery pack of FIG. 9, seen from diagonally below. 10. An exploded perspective view of the battery pack of FIG. 11, seen from diagonally below. 11. An exploded perspective view of the battery pack of FIG. 11, seen from diagonally below. 12. An exploded perspective view of the battery pack of FIG. 11, seen from diagonally below. 13. An exploded perspective view of the battery pack of FIG. 15, seen from diagonally below. 14. An exploded perspective view of the battery pack of FIG. 15, seen from diagonally below. 15. An exploded perspective view of the battery pack of FIG. 1, seen from diagonally below. 16. An exploded perspective view of the battery pack of FIG. 16, seen from diagonally below. 17. An exploded perspective view of the battery pack of FIG. 16, seen from diagonally below. 18. An exploded perspective view of the battery pack of FIG. 16, seen from diagonally below. 19. An exploded perspective view of the battery pack of FIG. 17, seen from diagonally below. 20. An exploded perspective view of the battery pack of FIG. 28, 19. An exploded perspective view of the battery pack of FIG. 19. An enlarged perspective view of the battery pack of FIG. 19, as seen from the back. An exploded perspective view of the battery pack of FIG. 21. A cross-sectional perspective view of the battery pack of FIG. 19, taken along line XXIII-XXIII. A cross-sectional perspective view of the battery pack of FIG. 19, taken along line XXIV-XXIV. A perspective view of a battery pack according to a third embodiment. An exploded perspective view of the battery pack of FIG. 25. An enlarged perspective view of the battery pack of FIG. 25, as seen from the back. An exploded perspective view of the battery pack of FIG. 27. A perspective view of the second plate portion of FIG. 26, as seen from diagonally below, as it is being slid into the frame. A perspective view of the state in which the second plate groove insertion piece is positioned in the guide recess, as seen from the state of FIG. 29. A cross-sectional perspective view of the battery pack of FIG. 25, taken along line XXXI-XXXI. A cross-sectional perspective view of the battery pack of FIG. 25, taken along line XXXII-XXXII. A cross-sectional perspective view of the battery pack of FIG. 25, taken along line XXXIII-XXXIII. A cross-sectional perspective view of the battery pack of FIG. 25, taken along line XXXIII-XXXIII. A perspective view of a battery pack according to a fourth embodiment. A cross-sectional perspective view of the battery pack of FIG. 34, as seen from diagonally below. Fig. 37 is an exploded perspective view of the battery pack of Fig. 34. Fig. 38 is an enlarged perspective view of the battery pack of Fig. 34 as seen from the rear. Fig. 39 is an exploded perspective view of the battery pack of Fig. 37.41. A cross-sectional perspective view taken along line XXXIX-XXXIX of the battery pack of FIG. 34. A perspective view showing a battery pack according to embodiment 5. An exploded perspective view of the battery pack of FIG. 40. A further exploded perspective view of the battery pack of FIG. 41. An enlarged perspective view of the battery pack of FIG. 41 as seen from the rear. An exploded perspective view of the battery pack of FIG. 43. A cross-sectional perspective view taken along line XLV-XLV of the battery pack of FIG. 41. A cross-sectional perspective view taken along line XLVI-XLVII of the battery pack of FIG. 41. A cross-sectional perspective view taken along line XLVII-XLVIII of the battery pack of FIG. 41. A cross-sectional perspective view taken along line XLVIII-XLVIII of the battery pack of FIG. 41. A cross-sectional perspective view of the battery pack of FIG. 41. A cross-sectional perspective view taken along line XLVIII-XLVIII of the battery pack of FIG. 41. A perspective view showing a frame of the battery pack of FIG. 42.

[0010] The embodiments of the present disclosure may be specified by the following configurations and features.

[0011] In a battery pack according to another aspect of the present disclosure, in the above aspect, the fixing means is an adhesive label wrapped around a cell assembly in which the first main surface of the secondary battery cell is covered with the first plate portion, the second main surface of the cell is covered with the second plate portion, and the pair of cell side surfaces are covered with the frame. This configuration improves insulation and enhances safety by covering the edges of the first plate portion and the second plate portion with the label.

[0012] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the fixing means is a second adhesive body attached between the second cell main surface of the secondary battery cell and the first second plate surface of the second plate portion opposite the second cell main surface. With this configuration, the second adhesive body can easily fix the second plate portion to the second cell main surface, allowing the second plate portion to follow the expansion of the secondary battery cell.

[0013] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the second connection structure is configured to allow the second plate portion to be displaced between the pair of frame walls in a direction toward the first plate portion when the secondary battery cell is in a contracted state from an expanded state. With this configuration, when the secondary battery cell returns from the expanded state to the contracted state, the second plate portion can be displaced to restore the original state.

[0014] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the second connection structure includes a displacement restriction means for restricting the amount of displacement of the second plate portion in a direction away from the first plate portion. With this configuration, even if the secondary battery cells expand, the displacement restriction means restricts the amount of displacement, thereby preventing the secondary battery cells from becoming detached from the frame body.

[0015] In yet another aspect of the battery pack disclosed herein, in any of the above aspects, the second plate portion includes second plate side walls on its longitudinal side surfaces, the pair of frame wall portions of the frame body form frame guide portions on their outer surfaces that guide the undersides of the second plate side walls, and the displacement restriction means includes second plate groove insert pieces formed at least partially on the second plate side walls and frame second protrusion pieces formed at least partially above and spaced apart from the frame guide portions, so that when the second plate groove insert pieces displace upward, the frame second protrusion pieces interfere with them. With this configuration, when a secondary battery cell expands and the second plate portion attempts to displace upward, the second plate groove insert pieces interfere with the frame second protrusions at a certain position, thereby restricting further displacement.

[0016] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the frame guide portion has a guide recess formed below the position where the frame second protrusion is provided, the guide recess having the same width as or larger than the frame second protrusion when the second plate portion is connected to the frame body. With the above configuration, the second plate portion can be attached to the frame body by inserting and locking it from the middle without having to move the entire length of the frame body along the longitudinal direction, making the attachment work easy.

[0017] Furthermore, in a battery pack according to another embodiment of the present disclosure, in any of the above embodiments, the first plate portion has a first plate side wall at least partially on the longitudinal side surface, at least one of the longitudinal end faces is flat, and the first connecting structure is implemented by a sliding mechanism that slides the first plate side wall of the first plate portion on the surfaces of the pair of frame wall portions of the frame body.

[0018] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the sliding mechanism includes a first sliding groove formed along the longitudinal direction on the outer surfaces of the pair of frame wall portions of the frame body, and a folded-back piece formed by folding back an edge of the first plate side wall of the first plate portion and insertable into the first sliding groove. This configuration has the advantage of making it easier to design the folded-back piece formed on the first plate side wall of the metal first plate.

[0019] In addition, in the battery pack according to any one of the above aspects, the second connection structure includes wall protrusions formed on the pair of frame walls of the frame body.

[0020] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the edge of the first plate portion is curved. With this configuration, the edge does not protrude from the front edge of the metal first plate portion, preventing the user's hand or other object from touching the edge, thereby improving safety.

[0021] In a battery pack according to another aspect of the present disclosure, in any of the above aspects, the edge of the second plate portion is curved. This configuration has the advantage that the inside of the battery pack is less visible to the user even if the secondary battery cell expands.

[0022] Furthermore, in a manufacturing method of a battery pack according to another embodiment of the present disclosure, in any of the above embodiments, the step of connecting the frame body and the first plate portion is carried out by bringing a flat first plate insertion end of one of the longitudinal end faces of the first plate portion between first plate side walls, each of which has a bent longitudinal side surface, close to the longitudinal end face of the frame body, and sliding the first plate side wall of the first plate portion against the outer surfaces of the pair of frame wall portions of the frame body.

[0023] In a battery pack according to still another aspect of the present disclosure, in any of the above aspects, the step of connecting the frame body and the first plate portion is performed by inserting and sliding a folded piece formed by folding back an edge of the first plate side wall of the first plate portion into a first slide groove formed along the longitudinal direction on the outer surfaces of the pair of frame wall portions of the frame body, which has the advantage of making it easier to design the folded piece formed on the first plate side wall of the metal first plate.

[0024] Embodiments of the present disclosure will be described below with reference to the drawings. However, the embodiments described below are merely examples for embodying the technical concepts of the present disclosure, and the present disclosure is not limited to the following. Furthermore, this specification does not in any way specify the components set forth in the claims to be those of the embodiments. The dimensions, materials, shapes, relative positions, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples, unless otherwise specified. The size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate components that are identical or of the same quality, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present disclosure may be configured with the same components, such that multiple elements are shared by one component, or conversely, the functions of one component may be shared by multiple components.

[0025] The battery pack of the present disclosure can be used as a driving power source for portable electronic devices such as smartphones, tablets, music players, and game consoles, as a power source for portable electrical devices such as radios, electric cleaners, and power tools, as a driving power source for mobile objects such as assisted bicycles, electric carts, and electric scooters, as a backup power source for servers in stationary power storage applications, as a power supply device for home, office, and factory use, and as a driving power source for vehicles such as hybrid cars and electric cars. Below, a battery pack used as a driving power source for a game console will be described as one embodiment of the present disclosure.

[0026] [Embodiment 1] A battery pack 100 according to embodiment 1 of the present disclosure is shown in Figures 1 to 18. In these figures, Figure 1 is a perspective view showing the battery pack 100 according to embodiment 1, Figure 2 is a perspective view of the battery pack 100 of Figure 1 as seen obliquely from below, Figure 3 is an exploded perspective view of the battery pack 100 of Figure 1, Figure 4 is a sectional perspective view of the battery pack 100 of Figure 1 taken along line IV-IV, Figure 5 is an enlarged perspective view of the battery pack 100 of Figure 1 as seen from the rear, Figure 6 is an exploded perspective view of the battery pack 100 of Figure 5, Figure 7 is an exploded perspective view showing the state in which the first plate portion 30 is being inserted into the frame body 20, Figure 8 is an exploded perspective view of Figure 7 as seen obliquely from below, Figure 9 is an exploded perspective view showing the state in which a secondary battery cell 10 is being set into the frame body 20 of Figure 7, and Figure 10 is an exploded perspective view showing the state in which a second plate portion 30 is being inserted into the secondary battery cell 10 of Figure 9. Fig. 13 is an exploded perspective view showing the assembly process of the battery pack 100' according to the modified example, Fig. 14 is a cross-sectional perspective view of the battery pack 100 of Fig. 1 taken along line XIV-XIV, Fig. 15 is a schematic cross-sectional view of the battery pack 100 of Fig. 1, Fig. 16 is a schematic cross-sectional view of the battery pack 100 of Fig. 15 taken along line XVII-XVII, and Fig. 18 is a cross-sectional perspective view of the battery pack 100 of Fig. 1 taken along line XVIII-XVIII. As shown in Figs. 1 and 2, the battery pack 100 has a plate-like outer shape. 3, the battery pack 100 is composed of secondary battery cells 10, a frame 20, a first plate portion 30, and a second plate portion 40. By holding the secondary battery cells 10 in this manner using the frame 20 rather than housing them in an exterior case such as plastic, the battery pack 100 can be made smaller and thinner.

[0027] (Secondary Battery Cell 10) The secondary battery cell 10 is a type known as a prismatic laminate battery or a pouch battery. While lithium-ion secondary batteries are primarily used as such secondary battery cells 10, other types of secondary battery cells may be used as appropriate. The prismatic secondary battery cell 10 has a first cell main surface 11, a second cell main surface 12 opposing the first cell main surface 11, and a pair of cell side surfaces 13 connecting the first cell main surface 11 and the second cell main surface 12. In the example shown in FIG. 3 , the first cell main surface 11 constitutes the lower surface, and the second cell main surface 12 constitutes the upper surface. The secondary battery cell 10 also has positive and negative electrodes.

[0028] (Frame 20) The frame 20 mainly covers the cell side surfaces 13 of the secondary battery cells 10. The frame 20 is annular and rectangular, forming a space 21 therein for accommodating the secondary battery cells 10. The frame 20 also has a pair of frame walls 22 that cover at least one pair of cell side surfaces 13 of the secondary battery cells 10. The pair of frame walls 22 are connected at their ends. In the example shown in FIG. 3 , the frame 20 includes a pair of frame walls 22, a frame front surface 23 that connects one end of the pair of frame walls 22, and a frame back surface 24 that connects the other end of the pair of frame walls 22. The frame front surface 23 and the frame back surface 24 may be formed with protrusions or screw holes for fixing or positioning, as necessary. The frame front surface 23 may also be provided with external electrodes 15, as shown in FIG. 2 . The external electrodes 15 are connected to the electrodes of the secondary battery cells 10. This frame 20 is made of a material with excellent insulating properties, heat resistance, and weather resistance. Preferably, the pair of frame walls 22, the front frame portion 23, and the rear frame portion 24 that constitute the frame body 20 are integrally molded from a resin or the like. The resin that can be used to constitute the frame body 20 includes polycarbonate (PC), polyamide (PA), polypropylene (PP), ABS resin, and the like.

[0029] (First Plate Portion 30) The first plate portion 30 is connected to the frame body 20 by a first connection structure. The first plate portion 30 is also fixed to the first cell main surface 11 of the secondary battery cell 10 via a first adhesive body 50. The first plate portion 30 is preferably made of a metal plate material. Examples of metal materials that can be used to make the first plate portion 30 include SUS and surface-coated iron.

[0030] (First Plate Side Walls 32) The first plate portion 30 has first plate side walls 32 at least partially on its longitudinal side surfaces. In the example of Fig. 3, the first plate side walls 32 are provided on the entirety of both side surfaces. The first plate side walls 32 are formed by bending both side ends of the metal plate first plate portion 30 at approximately right angles. Furthermore, by making the bent portions curved, it is possible to avoid the formation of edges on the end edges, and to avoid damage even if the corners come into contact with other components, etc., during assembly of the battery pack 100, etc.

[0031] (First Plate Insertion End 33) At least one of the longitudinal end faces of the first plate portion 30 is formed as a flat first plate insertion end 33. This allows the first plate portion 30 to be slidably connected to the frame body 20 from the first plate insertion end 33 using a sliding mechanism of the first connection structure, which will be described later. Note that the flatness of the first plate insertion end 33 does not require a completely flat surface; the end face may have a slight curved surface. For example, as shown in FIG. 4 , forming a slight curve on the first plate insertion end 33, which is the longitudinal end face of the first plate portion 30, allows the resin frame body 20 to be slightly deformed so that the first plate insertion end 33 can be inserted from the frame back surface portion 24. Furthermore, providing a curved surface on the first plate insertion end 33 in this manner prevents an edge from being exposed on the end face, making it less likely for the end face to come into contact with other components, etc., during assembly of the battery pack 100, thereby avoiding damage. As will be described later, when the secondary battery cell 10 expands and the second plate portion 40 rises, the inside of the secondary battery cell 10 can be seen from the end face, but by bending the end face downward, it has the effect of being hidden, making it difficult to see.

[0032] Furthermore, the other longitudinal end face of the first plate portion 30, which faces the first plate insertion end 33, is defined as a first plate end wall 34. As shown in FIG. 5 and other figures, the first plate end wall 34 may also be formed with a wall similar to the first plate side wall 32.

[0033] (First Connection Structure) The first plate portion 30 and the frame body 20 have a first connection structure for connecting them. The first connection structure can utilize a sliding mechanism that slides the first plate side walls 32 of the first plate portion 30 on the surfaces of a pair of frame wall portions 22 of the frame body 20. Specifically, as shown in FIGS. 5 and 6 , a first sliding groove 25 is formed along the longitudinal direction on the outer surface of the frame wall portion 22. The first sliding groove 25 extends along the longitudinal direction from the rear end of the frame wall portion 22 to just before the frame front portion 23. In order to form the first sliding groove 25, the lower end of the frame wall portion 22 forms a frame first protrusion 26 that protrudes toward the side in a cross-sectional view intersecting the longitudinal direction.

[0034] (First Plate Groove Insert Piece 35) The first plate side wall 32 of the first plate portion 30 further folds its edge to form a first plate groove insert piece 35 that can be inserted into the first slide groove 25. In this way, the first plate portion 30 can be connected to the frame body 20 by inserting the first plate groove insert piece 35 into the first slide groove 25 and sliding it. When sliding the first plate portion 30 into the frame body 20, as shown in FIGS. 7 and 8 , the first plate insertion end 33, which is the longitudinal end face of the first plate portion 30, is inserted so as to straddle the underside of the frame back surface portion 24 of the first plate portion 30. Then, the first plate groove insert piece 35 is inserted into the first slide groove 25 and pushed forward, i.e., toward the frame front surface portion 23. Finally, the first plate groove insert piece 35 abuts against the end face of the first slide groove 25. In this way, the first plate portion 30 can be connected to the frame body 20 without using members such as screws. The bottom surface of the frame wall portion 22 where the first slide groove 25 is formed is thinner by the thickness of the first plate so that the bottom surface of the frame front surface portion 23 and the bottom surface of the first plate portion 30 are flush with each other when the first plate portion 30 is inserted into the frame body 20. Furthermore, the thickness of the frame wall portion 22 is thinner by the thickness of the first plate in the area where the first slide groove 25 is formed so that the side surface of the frame front surface portion 23 and the first plate side wall 32 are flush with each other when the first plate portion 30 is inserted into the frame body 20. As a result, by configuring the battery pack 100 from two parts, the frame body 20 and the first plate portion 30, and devising a joining mechanism for these parts, it is possible to avoid an increase in thickness and size due to the addition of a joining mechanism, and to maintain the small size and thinness of the battery pack 100.

[0035] [Battery Pack Manufacturing Method] Here, a battery pack manufacturing method for assembling the battery pack 100 will be described. First, the secondary battery cell 10, the first plate portion 30, the second plate portion 40, and the frame body 20 are prepared. In this state, the first plate portion 30 is slid between the pair of frame wall portions 22 of the frame body 20 to connect the frame body 20 and the first plate portion 30. Here, as shown in FIG. 7 , the first plate insertion end 33 of the first plate portion 30 is slid in a pushing manner from the frame back surface portion 24 of the frame body 20. At this time, the resin frame body 20 is slightly deformed so that the slightly curved surface formed on the first plate insertion end 33 straddles the frame back surface portion 24, as shown in FIG. 8 . In this state, the first plate groove insertion piece 35 is inserted into the first slide groove 25 and slid.

[0036] 9 , the secondary battery cell 10 is inserted between the pair of frame wall portions 22 of the frame body 20, and the first cell main surface 11 of the secondary battery cell 10 is fixed to the first plate portion 30 via the first adhesive body 50. The first adhesive body 50 may be attached to the first cell main surface 11 side of the secondary battery cell 10 in advance, or may be attached to the first plate portion 30.

[0037] 10 , the second plate portion 40 is fixed to the second cell main surface 12 of the secondary battery cell 10 via a fixing means. Here, double-sided tape is used as the fixing means. The double-sided tape fixing means may be attached to the second cell main surface 12 side of the secondary battery cell 10 in advance, or may be attached to the second plate portion 40.

[0038] In this way, the first plate portion 30 is fixed to the frame body 20 while the second plate portion 40 is not fixed to the frame body 20, so that even if the secondary battery cell 10 expands and the thickness between the pair of side surfaces increases, deformation can be tolerated by moving the second plate portion 40 side.

[0039] (First adhesive body 50) Double-sided tape can be suitably used for the first adhesive body 50. It is preferable that the double-sided tape is thin. For example, the thickness of the double-sided tape is 0.1 mm to 1.0 mm. The substrate constituting the double-sided tape can be a polyester film, a polyethylene film, a polypropylene film, a cloth, a metal foil, or the like. Furthermore, the adhesive applied to both sides of the substrate can be an acrylic, epoxy, silicone, polyurethane, or the like.

[0040] (Second Plate Portion 40) The second plate portion 40 is connected to the frame body 20 by a second connecting structure. The second plate portion 40 is also fixed to the second cell main surface 12 of the secondary battery cell 10 via a fixing means. The surface of the second plate portion 40 that faces the second cell main surface 12 of the second plate portion 40 is referred to as the first second plate surface 41. The second plate portion 40 is also preferably made of a metal plate material. More preferably, the first plate portion 30 and the second plate portion 40 are made of metal plates of the same material.

[0041] The second plate portion 40 includes second plate side walls 42 on its longitudinal side surfaces. Second plate end walls 44 may also be formed on its longitudinal end surfaces. In the example shown in FIG. 3 and other figures, the second plate side walls 42 are formed on the longitudinal side surfaces of the second plate portion 40, and the second plate end wall 44 is formed on one of its longitudinal end surfaces (the right side in FIG. 3 ). By bending the edges of the second plate portion 40 in this manner, the edges of the metal second plate portion 40 are prevented from being exposed to the outside, reducing the risk of damage when the edges of the second plate portion 40 come into contact with other components during assembly, etc. Additionally, as shown in FIGS. 17 and 18 (described later), the folding of the edges also provides a concealing effect, obscuring the possibility that the interior of the secondary battery cell 10 may become visible when the second plate portion 40 expands and lifts up.

[0042] (Fixing Means) The fixing means fixes the second plate portion 40 to the cell second main surface 12 of the secondary battery cell 10. For such fixing means, a second adhesive body 60 attached between the cell second main surface 12 of the secondary battery cell 10 and the second plate first surface 41 of the second plate portion 40 can be used. With such second adhesive body 60, the second plate portion 40 can be easily fixed to the cell second main surface 12, and the second plate portion 40 can follow the expansion of the secondary battery cell 10. The second adhesive body 60 can be double-sided tape.

[0043] The fastening means is not limited to the second adhesive body 60. For example, the fastening means may be an adhesive label 65 wrapped around the cell assembly 1, which includes the first plate portion 30 covering the first main surface 11 of the secondary battery cell 10, the second plate portion 40 covering the second main surface 12 of the secondary battery cell 10, and the frame 20 covering the pair of side surfaces. Such an example is shown in FIGS. 11 and 12 as a battery pack 100′ according to a modified example. In these modified examples, the same components as those in the first embodiment are designated by the same reference numerals, and detailed descriptions are omitted as appropriate. The label 65 is preferably made of an insulating material such as paper or resin. By wrapping the cell assembly 1 with the label 65 after assembling the secondary battery cell 10, the frame 20, the first plate portion 30, and the second plate portion 40, the second plate portion 40 can be easily fixed to the secondary battery cell 10. Furthermore, the entire battery assembly, including the second plate portion 40, can be held together. Furthermore, covering most of the metallic first plate portion 30 and second plate portion improves insulation. Furthermore, if the metal first plate portion 30 and second plate portion 40 have sharp edges, they may be damaged when they come into contact with other components during assembly, etc., but by covering them with label 65, there is an advantage that the exposure of the edges is reduced, thereby increasing safety.

[0044] Regarding the illustration of the label 65, in the example of the exploded perspective view in Figure 12 and the like, for convenience of drawing, the label 65 is shown in a folded state, but in actual assembly, the label 65 is laid out flat and then folded in a rolled-up manner, following a known label attachment process.

[0045] In this way, the second adhesive body 60 or the label 65 can be used as the fixing means. Either the second adhesive body 60 or the label 65 may be used, or both may be used in combination. Furthermore, not only in embodiment 1, but also in each of the following embodiments, either the second adhesive body 60 or the label 65, or both, can be used as the fixing means. However, for convenience of explanation, only one of them will be illustrated and described.

[0046] A manufacturing method of a battery pack 100′ using a label 65 as the fastening means is as follows. The steps of preparing the secondary battery cell 10, the first plate member 30, the second plate member 40, and the frame body 20, and connecting the frame body 20 to the first plate member 30, and the step of fixing the first cell main surface 11 of the secondary battery cell 10 to the first plate member 30 via the first adhesive body 50 are the same as those shown in FIGS. 7 and 9 . Next, the step of fixing the second plate member 40 to the second cell main surface 12 of the secondary battery cell 10 via the fastening means is performed by wrapping the label 65 around the cell assembly 1 in a state where the cell assembly 1 is assembled with the secondary battery cell 10, the frame body 20, the first plate member 30, and the second plate member 40, as shown in FIG. 13 . This allows the second plate member 40 to be easily fixed to the secondary battery cell 10.

[0047] (Second Connection Structure) The second connection structure is configured to allow the second plate portion 40 to be displaced in a direction away from the first plate portion 30 between the pair of frame wall portions 22 when the secondary battery cell 10 is expanded. In this way, the first plate portion 30 is fixed to the first surface of the secondary battery cell 10, while the second plate portion 40 is not fixed to the frame body 20. Therefore, even if the secondary battery cell 10 expands and the thickness between the pair of side surfaces increases, deformation can be tolerated by displacing the second plate portion 40 accordingly.

[0048] It is known that secondary battery cells expand during charging and discharging. Generally, they expand during charging and contract during discharging, returning to their original shape. Therefore, it is desirable for a battery pack to have the ability to restore its original shape after contraction, even if it expands. However, if the metal plate expands and deforms during storage in a metal exterior case, and remains swollen without returning to its original shape, this creates an unsightly appearance and is undesirable at the interface with the device to be powered by the battery pack. Therefore, it is desirable to have a configuration that prevents the metal first and second plate portions from deforming when the secondary battery cells expand.

[0049] In this embodiment, as shown in the cross-sectional view of FIG. 14 , the first plate portion 30 is fixed to the first cell main surface 11 of the secondary battery cell 10, and the second plate portion 40 is configured to displace during expansion. In this case, the first plate portion 30 is fixed to the frame body 20, while the second plate portion 40 is not fixed to the frame body 20, allowing for displacement by the second connection structure. That is, as shown in the schematic cross-sectional views of FIGS. 15 and 16 , even if the thickness of the second plate portion 40 increases between the pair of side surfaces due to expansion of the secondary battery cell 10, displacement of the second plate portion 40 between the pair of frame wall portions 22 in a direction away from the first plate portion 30 is permitted. For the purpose of explanation, the schematic cross-sectional views of FIGS. 15 and 16 are exaggerated to clearly show differences, such as the thickness of the secondary battery cell 10.

[0050] 16 to 15 , when the secondary battery cell 10 changes from an expanded state to a contracted state, the second connection structure allows the second plate portion 40 to be displaced in a direction approaching the first plate portion 30 between the pair of frame wall portions 22. In other words, as the secondary battery cell 10 returns from the expanded state to the contracted state, the second plate portion 40 can be displaced in the opposite direction to restore the original state.

[0051] (Frame Groove 19) The second connecting structure can utilize, for example, a frame groove 19 formed in a pair of frame wall portions 22 of the frame body 20, with the frame groove 19 opening upward and allowing the second plate side wall 42 to be inserted. In the example of the cross-sectional perspective view of FIG. 14 , the frame groove 19 is formed by protruding from the outer surface of the frame wall portion 22 in an L-shape in cross section. The width of the frame groove 19 is approximately the same as or slightly narrower than the second plate side wall 42 so that the second plate side wall 42 of the second plate portion 40 can be inserted. By integrally forming the frame body 20 with the frame groove 19 using a flexible resin or the like, the second plate side wall 42 can be press-fit into the frame groove 19 to connect the second plate portion 40 to the frame body 20. Furthermore, by opening the frame groove 19 upward and allowing the second plate side wall 42 to protrude downward, the second plate portion 40 can move up and down.

[0052] The second connecting structure may be provided not only in the longitudinal direction of the second plate portion 40 but also in the lateral direction. That is, the frame upper groove 19 into which the second plate end wall 44 of the second plate portion 40 is inserted may be provided in the frame front portion 23 or the frame back portion 24. In the example of FIG. 17 , the frame upper groove 19 is formed in the frame back portion 24, and is configured to insert the second plate end wall 44 of the second plate portion 40. Furthermore, the first plate end wall 34 may also have a wall surface similar to the first plate side wall 32, and the tip may be bent to cover the frame first protrusion 26. In this example, as shown in FIG. 18 , no frame upper groove is formed in the frame front portion 23.

[0053] (Displacement restriction means) The second connection structure may also include a displacement restriction means that restricts the amount of displacement of the second plate portion 40 in the direction away from the first plate portion 30. By restricting the amount of displacement with the displacement restriction means, even if the secondary battery cell 10 expands, it is possible to prevent the secondary battery cell 10 from coming off the frame body 20.

[0054] [Embodiment 2] Such an example is shown in Figures 19 to 24 as a battery pack 200 according to embodiment 2. In these figures, Figure 19 is a perspective view of the battery pack 200 according to embodiment 2, Figure 20 is an exploded perspective view of the battery pack 200 of Figure 19, Figure 21 is an enlarged perspective view of the battery pack 200 of Figure 19 as seen from the rear, Figure 22 is an exploded perspective view of the battery pack 200 of Figure 21, Figure 23 is a cross-sectional perspective view of the battery pack 200 of Figure 19 taken along line XXIII-XXIII, and Figure 24 is a cross-sectional perspective view of the battery pack 200 of Figure 19 taken along line XXIV-XXIV. In these figures, components similar to those of embodiment 1 described above are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. The battery pack 200 according to embodiment 2 also has a plate-like outer shape, as shown in Figure 19. As shown in FIG. 20, the battery pack 200 includes a first plate portion 30, a second plate portion 40B, and a frame body 20B.

[0055] (Second Plate Groove Insertion Piece 45) In this battery pack 200, the second connecting structure is equipped with a displacement restriction means. The displacement restriction means restricts the amount of displacement of the second plate portion 40B in the direction away from the first plate portion 30. The second plate portion 40B has a second plate groove insertion piece 45 formed at least partially in the second plate side wall 42B as the displacement restriction means. In the example shown in Figures 21 to 23, the second plate groove insertion piece 45 is formed over the entire area of ​​the second plate side wall 42B.

[0056] (Frame guide portions 29) On the other hand, as shown in Fig. 22, the pair of frame wall portions 22B of the frame body 20B have frame guide portions 29 formed on their outer surfaces that guide the undersides of the second plate side walls 42B. The frame guide portions 29 are spaced apart from the upper ends of the frame wall portions 22B and extend along the longitudinal direction of the frame wall portions 22B at the middle of the frame wall portions 22B. A first slide groove 25 is formed in the lower portion of the frame wall portions 22B.

[0057] (Frame Second Protrusion 28) Furthermore, a frame second protrusion 28 is formed at the upper end of the frame wall portion 22B, protruding laterally in a cross-sectional view intersecting the longitudinal direction. The frame second protrusion 28 is formed at least partially, spaced above the frame guide portion 29. In the examples shown in FIGS. 20 and 22, the frame second protrusion 28 is formed on the entire outer surface of the frame wall portion 22B along the longitudinal direction of the frame body 20B. In the examples shown in FIGS. 22 and 23, a frame first protrusion 26 is formed on the lower end of the outer surface of the frame wall portion 22B, and a frame second protrusion 28 is formed on the upper end. The frame first protrusion 26 and the frame second protrusion 28 are each spaced apart from the frame guide portion 29, and a first sliding groove 25 and a second sliding groove 27 are formed between them, respectively. This frame body 20B is connected to the second plate portion 40B by sliding it on the frame body 20B, like the first plate portion 30. 21 and 23, the second plate groove insert piece 45 of the second plate portion 40B is inserted into the second sliding groove 27, and the second plate portion 40B is slid along the longitudinal direction of the frame body 20B to connect them. At this time, the frame guide portion 29 guides the lower end of the second plate groove insert piece 45.

[0058] The frame second protrusion 28 functions as a displacement restriction mechanism. When the second plate portion 40B is set in the frame body 20B and the second plate groove insertion piece 45 is displaced upward, the frame second protrusion 28 interferes when it reaches a certain height. With this configuration, when the rechargeable battery cell 10 expands and the second plate portion 40B attempts to displace upward, the second plate groove insertion piece 45 interferes with the frame second protrusion 28 at a certain position, restricting further displacement. This prevents the rechargeable battery cell 10 from coming off the frame body 20B.

[0059] The second plate groove insertion piece 45 may also be provided on the second plate end wall 44B of the second plate portion 40B. By providing the frame second protrusion 28 on the frame back surface portion 24B, a displacement restriction means can be similarly provided on the longitudinal end surface side of the second plate portion 40B, thereby preventing the second plate portion 40B from coming off the frame body 20B. As shown in the cross-sectional perspective view of Figure 24, a configuration in which no frame second protrusion is provided on the frame back surface portion 24B may also be adopted. Alternatively, the thickness of the frame second protrusion 28C may be thinned, as shown in Figure 32, which will be described later.

[0060] Third Embodiment In the above example, the frame second protrusion 28 is formed over the entire longitudinal length of the frame body 20. However, the present disclosure is not limited to this configuration, and the frame second protrusion may be formed partially along the longitudinal length of the frame body. Such an example is shown in Figures 25 to 33 as a battery pack 300 according to a third embodiment. 27 is an enlarged perspective view of the battery pack 300 of FIG. 25 as viewed from the back; FIG. 28 is an exploded perspective view of the battery pack 300 of FIG. 27; FIG. 29 is a perspective view of the second plate portion 40C of FIG. 26 as viewed from diagonally below, showing the state in which it is being slid into the frame body 20C; FIG. 30 is a perspective view showing the state in which the second plate groove insertion piece 45C is positioned in the guide recess 29n from the state of FIG. 29; FIG. 31 is a cross-sectional perspective view of the battery pack 300 of FIG. 25 taken along line XXXI-XXXI; FIG. 32 is a cross-sectional perspective view of the battery pack 300 of FIG. 25 taken along line XXXII-XXXII; and FIG. 33 is a cross-sectional perspective view of the battery pack 300 of FIG. 25 taken along line XXXIII-XXXIII. In these figures, the same components as those in the first embodiment and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate. The battery pack 300 according to the third embodiment also has a plate-like outer shape as shown in Fig. 25. Furthermore, as shown in Fig. 26, the battery pack 300 includes a first plate portion 30C, a second plate portion 40C, and a frame body 20C.

[0061] The frame body 20C shown in Figures 26 and 28 has frame second protrusions 28C formed partially along the longitudinal direction of the frame body 20C. In other words, as shown in Figures 27 and 28, the frame second protrusions 28C are provided intermittently in the extension direction, with multiple frame second protrusions 28C formed in an island shape. Furthermore, the positions of the frame second protrusions 28C correspond to the respective second plate groove insert pieces 45C of the second plate side wall 42C when the second plate portion 40C is connected to the frame body 20C. As a result, when the second plate portion 40C is connected to the frame body 20C, the respective second plate groove insert pieces 45C come into contact with the frame second protrusions 28C, thereby properly functioning as a displacement restriction means.

[0062] (Second Communication Spaces 28n) Meanwhile, as a result of providing the frame second protrusions 28C intermittently in this manner, second communication spaces 28n without frame second protrusions 28C are formed between adjacent frame second protrusions 28C, as shown in FIG. 28 . In other words, at the upper end of the frame body 20C, the flat surface of the frame wall portion 22C is exposed, forming second communication spaces 28n that communicate with the second slide groove 27C. The width of the second communication spaces 28n is the same as or slightly larger than the width of the second plate groove insert pieces 45C formed in the second plate end wall 44C of the second plate portion 40C. Furthermore, the second communication spaces 28n are positioned corresponding to the second plate groove insert pieces 45C, offset by the length of the frame second protrusions 28C from the state in which the second plate portion 40C is connected to the frame body 20C. In other words, the number of second communication spaces 28n is equal to or greater than the number of second plate groove insert pieces 45C.

[0063] (Guide recess 29n) Furthermore, the frame guide portion 29C forms a guide recess 29n below the position where the frame second protrusion 28C is provided when the second plate portion 40C is connected to the frame body 20C. The width of the guide recess 29n is the same as or slightly larger than the width of the frame second protrusion 28C.

[0064] This configuration reduces the labor required to connect the second plate portion 40C to the frame body 20C. Specifically, during the process of inserting the second plate groove insert piece 45C of the second plate portion 40C into the second sliding groove 27C and sliding the second plate portion 40C along the longitudinal direction of the frame body 20C to connect the second plate portion 40C to the frame body 20C, the battery pack 100 of the first embodiment shown in FIG. 7 and elsewhere required the second plate portion 40C to slide along the entire longitudinal direction. In contrast, the battery pack 300 of the third embodiment only requires the second plate to be inserted from above the frame body 20C and moved horizontally the length of the frame second protrusion 28C. Specifically, as shown in FIG. 29 , when the second plate groove insert piece 45C is inserted into the second communicating space 28n, it passes through the second communicating space 28n and stops by abutting against the frame guide portion 29C. In this state, the second plate groove insert piece 45C is positioned in the second sliding groove 27C. From this position, by sliding the second plate portion 40C as shown by the arrow in FIG. 29, the second plate groove insert piece 45C falls into the guide recess 29n formed in the frame guide portion 29C, as shown in FIG. 30. That is, the second plate portion 40C sinks in by the depth of the guide recess 29n. In this state, as shown in FIG. 31, the second plate groove insert piece 45C can be displaced vertically with a stroke amount DS between the frame second protrusion 28C and the guide recess 29n. In this way, the second plate portion 40C can be inserted and locked from the middle without having to move the entire length of the frame body 20C along the longitudinal direction, simplifying the installation process. Furthermore, the stroke amount DS of the displacement of the second plate portion 40C can be regulated by the depth of the guide recess 29n.

[0065] Also, as in the above-described first embodiment, a displacement restriction means can be provided on the second plate end wall 44C of the second plate portion 40C. In a battery pack 300 according to the third embodiment, as shown in Fig. 32, the second plate end wall 44C is bent into a U-shape in cross section and inserted into an upper frame groove 19 formed in the frame back surface portion 24. Here, a gap is provided between the second frame protrusion 28C that forms the upper frame groove 19 and the U-shaped second plate end wall 44C, so that the gap coincides with the stroke amount DS.

[0066] (Second Plate Insertion End 43) A second plate insertion end 43 may also be provided on the surface of the second plate facing the second plate end wall 44C. In the example shown in Fig. 33, the second plate insertion end 43 is formed with a slightly curved surface, similar to the first plate insertion end 33, to prevent the edge from being exposed and also to function as a screen to make it difficult to see the inside of the battery pack 300 when the secondary battery cell 10 expands.

[0067] In the above example, a configuration was described in which the second connecting structure for connecting the second plate portion 40C to the frame body 20C was devised to allow the second plate portion 40C to be inserted into the frame body 20C from the middle. This configuration can be applied not only to the second plate portion 40C but also to the first plate portion 30C. That is, as shown in Figures 26, 28, 31, etc., the first plate groove insert piece 35C formed on the first plate side wall 32C is formed only on a portion of the first plate portion 30C in the longitudinal direction, rather than over the entire length of the first plate portion 30C. Correspondingly, the frame first protrusions 26 protruding from the lower end of the outer surface of the frame wall portion 22C are also formed in positions corresponding to the first plate groove insert piece 35C, rather than over the entire length of the frame body 20C in the longitudinal direction. As a result, first communication spaces are formed between adjacent frame first protrusions 26 formed in an island shape. The first communication spaces are in communication with the first slide grooves 25. By forming the width of this first communicating space to be the same as or wider than the width of the first plate groove insert piece 35C, the first plate groove insert piece 35C can be guided through the first communicating space into the first slide groove 25. As a result, the first plate portion 30C can be connected to the frame body 20C by inserting it from the underside of the frame body 20C and moving it horizontally. In other words, by inserting the first plate groove insert piece 35C into the first communicating space, it can pass through the first communicating space and be guided into the first slide groove 25. Therefore, by moving it horizontally the length of the frame first protrusion 26, the first plate groove insert piece 35C can be held in the first slide groove 25 and the first plate portion 30C can be connected to the frame body 20C.

[0068] [Embodiment 4] In the above examples, the first connecting structure was described as a configuration in which the edge of the first plate portion 30 was machined to form the first plate groove insert 35. However, the present disclosure does not limit the first connecting structure to this configuration, and other configurations may be adopted. In particular, the first plate groove insert 35 shown in Figures 5, 8, etc., has a problem in that the edge of the first plate portion 30 of the metal plate is bent at a substantially right angle, making it difficult to specify the length of the bent edge and maintaining dimensional accuracy. Therefore, it is conceivable to facilitate machining and improve accuracy by separating the position where the substantially right angle bend is made from the edge of the metal plate. As such an example, a battery pack 400 according to embodiment 4 will be described with reference to Figures 34 to 39. In these figures, Fig. 34 is a perspective view of a battery pack 400 according to the fourth embodiment, Fig. 35 is a perspective view of the battery pack 400 of Fig. 34 viewed obliquely from below, Fig. 36 is an exploded perspective view of the battery pack 400 of Fig. 34, Fig. 37 is an enlarged perspective view of the battery pack 400 of Fig. 34 viewed from the rear, Fig. 38 is an exploded perspective view of the battery pack 400 of Fig. 37, and Fig. 39 is a cross-sectional perspective view of the battery pack 400 taken along line XXXIX-XXXIX of Fig. 34. In these figures, components similar to those of the first embodiment and the like are designated by the same reference numerals, and detailed descriptions will be omitted as appropriate. The battery pack 400 according to the fourth embodiment also has a plate-like outer shape, as shown in Figs. 34 and 35. Furthermore, as shown in Fig. 36, the battery pack 400 includes a first plate portion 30D, a second plate portion 40, and a frame body 20.

[0069] 37 to 39, the first plate portion 30D has a folded piece 35D formed by folding back the tip of the first plate side wall 32D. The folded piece 35D is formed by folding back the edge of the first plate side wall 32D in a U-shape at a predetermined length, forming two overlapping pieces. This type of processing has the advantage of being relatively easy to perform because the length of the folded edge can be secured to a certain extent, and it is easy to ensure precision.

[0070] As shown in FIG. 38 and other figures, a folded piece 35D may also be formed on the edge of a first plate end wall 34D.

[0071] [Embodiment 5] In the above examples, the first and second connecting structures connecting the first plate portion 30 and the second plate portion 40 to the frame body 20 are described as using a sliding mechanism that utilizes the first sliding groove 25 and the second sliding groove 27 for sliding. However, the present disclosure is not limited to a configuration in which the first and second connecting structures are slid using grooves, and other connecting structures may be used. One such example is shown in Figures 40 to 49 as a battery pack 500 according to embodiment 5. In these figures, Figure 40 is a perspective view of the battery pack 500 according to embodiment 5, Figure 41 is an exploded perspective view of the battery pack 500 of Figure 40, Figure 42 is a further exploded perspective view of the battery pack 500 of Figure 41, Figure 43 is an enlarged perspective view of the battery pack 500 of Figure 41 as seen from the rear, Figure 44 is an exploded perspective view of the battery pack 500 of Figure 43, and Figure 45 is a perspective view of the battery pack 500 of Figure 41 along line XLV-XLV. FIG. 46 is a cross-sectional perspective view of the battery pack 500 of FIG. 41 taken along line XLVI-XLVI. FIG. 47 is a cross-sectional perspective view of the battery pack 500 of FIG. 41 taken along line XLVII-XLVIII. FIG. 48 is a cross-sectional perspective view of the battery pack 500 of FIG. 41 taken along line XLVIII-XLVIII. FIG. 49 is a perspective view of the frame body 20E of the battery pack 500 of FIG. 42. In these figures, components similar to those in the first embodiment and the like are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate. The battery pack 500 of the fifth embodiment also has a plate-like outer shape as shown in FIG. 40. Furthermore, as shown in FIG. 41, the battery pack 500 includes a first plate portion 30E, a second plate portion 40E, and a frame body 20E.

[0072] (First Plate Engagement Holes 38) The first plate portion 30E has a first plate sidewall 32E on a side surface in the longitudinal direction. The first plate sidewall 32E has a plurality of spaced-apart first plate engagement holes 38 formed therein. In the example shown in FIGS. 41 to 44, the first plate sidewall 32E is partially enlarged near the first plate engagement holes 38. Alternatively, as shown in FIG. 42, the first plate sidewall 32 may be partially enlarged around a plurality of adjacent first plate engagement holes 38. Each first plate engagement hole 38 is a rectangular opening that continues from the first plate main surface 31E of the first plate portion 30 to the first plate sidewall 32.

[0073] (First Frame Locking Pieces 71) The frame body 20E also has a plurality of spaced-apart first frame locking pieces 71 formed at the lower ends of the outer surfaces of a pair of frame wall portions 22E. The first frame locking pieces 71 are provided at positions corresponding to the first plate locking holes 38. In a cross section intersecting the longitudinal direction, each first frame locking piece 71 is formed in the shape of a right triangle with its hypotenuse tapering downward, as shown in FIG. 45 . The first frame locking piece 71, which has a right triangular cross section, has an upper surface that continues from a first inclined surface 72 that forms the hypotenuse, as a first flat surface 73. The first flat surface 73 is abutted against the inner surface of the first plate locking hole 38 to lock the first plate side wall 32E to the frame wall portion 22E. The frame body 20E having this structure is press-fitted from above between the first plate side walls 32E, and the first inclined surfaces 72 of the first frame locking pieces 71 are deformed to widen the space between the first plate side walls 32E, or to narrow the space between the pair of frame wall portions 22E as a reaction, thereby locking the first frame locking pieces 71 into the first plate locking holes 38. In this state, the height, i.e., the vertical length, of the first plate portions 30E is made to match the height, i.e., the vertical length, of the first frame locking pieces 71 so that the first plate portions 30E are not displaced in the up-down direction relative to the frame body 20E.

[0074] (Second Plate Locking Holes 48) Similarly, the second plate portion 40E has a second plate side wall 42E on its longitudinal side surface. The second plate side wall 42E also has a plurality of spaced-apart second plate locking holes 48 formed therein. In the example shown in Figures 41 to 44, the second plate side wall 42E is partially enlarged near the formation of the second plate locking holes 48. Each second plate locking hole 48 opens continuously from the main surface of the second plate portion 40E to the second plate side wall 42E in a rectangular shape.

[0075] (Second Frame Locking Pieces 81) The frame body 20E also has a plurality of spaced-apart second frame locking pieces 81 formed on the upper ends of the outer surfaces of a pair of frame wall portions 22E. The second frame locking pieces 81 are provided at positions corresponding to the second plate locking holes 48. In a cross section intersecting the longitudinal direction, each second frame locking piece 81 is formed in the shape of a right triangle with its hypotenuse tapering upward, as shown in FIG. 46 . The second frame locking piece 81, which has a right triangular cross section, has a second flat surface 83 on the lower surface continuing from a second inclined surface 82 that forms the hypotenuse. The second flat surface 83 is abutted against the inner surface of the second plate locking hole 48 to lock the second plate side wall 42E to the frame wall portion 22E. The frame body 20E having this structure is press-fitted from below between the second plate side walls 42E, and the second inclined surfaces 82 of the second frame locking pieces 81 are deformed to widen the space between the second plate side walls 42E or to narrow the space between the pair of frame wall portions 22E as a reaction, thereby locking the second frame locking pieces 81 into the second plate locking holes 48. As shown in Figure 46, the height, i.e., the vertical length, of the second plate locking holes 48 is made longer than the height, i.e., the vertical length of the second frame locking pieces 81 so that the second plate portion 40E is displaced upward when connected to the frame body 20E. This makes it possible to displace the second plate portion 40E up and down by a stroke amount DS due to the difference in height between the second plate locking holes 48 and the second frame locking pieces 81.

[0076] Furthermore, the first and second connecting structures formed by the first frame locking pieces 71 and first plate locking holes 38, and the second frame locking pieces 81 and second plate locking holes 48 can be added not only to the longitudinal side surfaces of the battery pack 500, but also to the end surface sides. In the examples of Figures 41, 42, and 47, first plate locking holes 38 and second plate locking holes 48 are similarly formed in the first plate end wall 34E of the first plate portion 30E and the second plate end wall 44E of the second plate portion 40E.

[0077] As shown in the cross-sectional view of FIG. 48, the first plate portion 30E has a first plate insertion end 33E that is similarly curved.

[0078] 43, 44, etc., on the outer surface of the frame wall portion 22E, the first frame locking pieces 71 and the second plate locking holes 48 are not aligned in the same position in the vertical direction but are offset from each other. By arranging them in this manner, as shown in FIGS. 45, 46, etc., when the first frame locking pieces 71 are locked in the first plate locking holes 38 and the second frame locking pieces 81 are locked in the second plate locking holes 48, even when the portions of the first plate sidewall 32E and the second plate sidewall 42E where the first plate locking holes 38 and the second plate locking holes 48 are formed are enlarged, interference between them is avoided, and a situation in which the frame wall portion 22 becomes thicker outward is avoided.

[0079] (Wall Protrusion 90) Furthermore, the frame wall portion 22E forms a wall protrusion 90 in the region of the first plate sidewall 32E and the second plate sidewall 42E where there are no enlarged portions around the first plate locking hole 38 and the second plate locking hole 48. The thickness of the wall protrusion 90 is set to be flush with the side surface of the first plate portion 30E and the second plate portion 40E when they are connected to the frame body 20E, i.e., approximately the same as the thickness of the first plate sidewall 32E and the second plate sidewall 42E or slightly thicker by a margin. Forming the wall protrusion 90 reinforces the frame body 20E by increasing its thickness in part. In addition, as shown in the perspective view of Figure 49, forming the wall protrusion 90 on the frame body 20E at a position spaced apart from the first frame locking piece 71 and the second frame locking piece 81 provides the advantage of adding strength to resist deformation of the frame body 20E.

[0080] In the above example, the battery pack is used as a power source for a portable electronic device such as a game console. However, the present disclosure is not limited to this. The battery pack can also be used for other purposes, such as attaching it to an electrical device to be driven and supplying power to the electrical device. Examples of electrical devices include portable electrical devices and moving objects such as electric vehicles and electric carts. In such electrical devices, when the remaining capacity of the battery pack becomes low or the battery pack deteriorates over time, the battery pack can be replaced to continue using the electrical device. However, the present disclosure is not limited to replaceable battery packs that mainly house secondary battery cells, but can also be applied to battery packs in which secondary battery cells are housed within the housing of the electrical device. In the present disclosure, a battery pack is defined as a battery pack that houses secondary battery cells in a case, and also includes battery packs in which secondary battery cells for driving the electrical device are built into the housing of the electrical device itself. In other words, the present disclosure is not limited to replaceable battery packs, but can also be applied to electrical devices that house secondary battery cells.

[0081] The battery pack and manufacturing method thereof according to the present disclosure can be suitably used as a power source for portable electronic terminals such as game consoles, as a power source for radios, as a power source for portable electrical equipment such as electric cleaners and power tools, as a power source for driving mobile objects such as electric assisted bicycles, electric carts and electric scooters, as a backup power source for servers and the like, and as a stationary power storage device for home, office and factory use, etc.

[0082] DESCRIPTION OF SYMBOLS 100, 100', 200, 300, 400, 500... Battery pack 1... Cell assembly 10... Secondary battery cell 11... Cell first main surface 12... Cell second main surface 13... Cell side surface 15... External electrode 19... Frame upper groove portion 20, 20B, 20C, 20E... Frame body 21... Space 22, 22B, 22C, 22E... Frame wall portion 23... Frame front portion 24, 24B... Frame back portion 25... First sliding groove 26... Frame first protrusion portion 27, 27C... Second sliding groove 28, 28C... Frame second protrusion portion 28n... Second communicating space 29, 29C... Frame guide portion 29n... Guide recess 30, 30C, 30D, 30E... First plate portion 31E... First plate main surface 32, 32C, 32D, 32E...First plate side wall 33, 33E...First plate insertion end 34, 34D, 34E...First plate end wall 35, 35C...First plate groove insertion piece 35D...Folded piece 38...First plate locking hole 40, 40B, 40C, 40E...Second plate portion 41...Second plate first surface 42, 42B, 42C, 42E...Second plate side wall 43...Second plate insertion end 44, 44B, 44C, 44E...Second plate end wall 45, 45C...Second plate groove insertion piece 48...Second plate locking hole 50...First adhesive body 60...Second adhesive body 65...Label 71...First frame locking piece 72...First inclined surface 73...First flat surface 81...Second frame locking piece 82...Second inclined surface 83...Second flat surface 90...Wall protrusion DS...Stroke amount

Claims

1. A battery pack comprising: a secondary battery cell having a cell first main surface; a cell second main surface opposite the cell first main surface; and a pair of cell side surfaces connected to the cell first main surface and the cell second main surface; a resin frame body having a pair of frame wall portions covering at least the pair of cell side surfaces of the secondary battery cell; a metal first plate portion connected to the frame body by a first connecting structure and fixed to the cell first main surface of the secondary battery cell via a first adhesive; and a metal second plate portion connected to the frame body by a second connecting structure and fixed to the cell second main surface of the secondary battery cell via fixing means, wherein the second connecting structure is configured to allow the second plate portion to be displaced between the pair of frame wall portions in a direction away from the first plate portion when the secondary battery cell is in an expanded state.

2. A battery pack as claimed in claim 1, wherein the fixing means is an adhesive label wrapped around the cell assembly, which covers the first main surface of the secondary battery cell with the first plate portion, the second main surface of the cell with the second plate portion, and the pair of cell side surfaces with the frame body.

3. A battery pack as claimed in claim 1, wherein the fixing means is a second adhesive body affixed between the second cell main surface of the secondary battery cell and the first surface of the second plate portion on the side opposite to the second cell main surface.

4. A battery pack as claimed in claim 1, wherein the second connection structure is configured to allow the second plate portion to be displaced in a direction approaching the first plate portion between the pair of frame wall portions when the secondary battery cell is in a contracted state from an expanded state.

5. A battery pack according to claim 1, wherein the second connecting structure is provided with a displacement restriction means for restricting the amount of displacement of the second plate portion in the direction away from the first plate portion.

6. A battery pack as claimed in claim 5, wherein the second plate portion has second plate side walls on its longitudinal side surfaces, the pair of frame wall portions of the frame body have frame guide portions on the outer surfaces of the pair of frame wall portions that guide the undersides of the second plate side walls, and the displacement restriction means comprises: a plate groove insertion piece provided on the second plate side wall at least partially in the longitudinal direction of the second plate side wall, and a frame second protrusion portion provided on the second plate side wall at least partially in the longitudinal direction of the second plate side wall, spaced above the frame guide portion, and wherein the frame second protrusion portion is configured to interfere when the plate groove insertion piece is displaced upward.

7. A battery pack as claimed in claim 6, wherein the frame guide portion has a guide recess below the position where the frame second protrusion portion is provided, the guide recess having the same width as or larger than the frame second protrusion portion when the second plate portion is connected to the frame body.

8. A battery pack as claimed in any one of claims 1 to 7, wherein the first plate portion has first plate side walls at least partially on the longitudinal side surfaces, at least one of the longitudinal end faces is flat, and the first connecting structure is achieved by a sliding mechanism that slides the first plate side walls of the first plate portion on the surfaces of the pair of frame wall portions of the frame body.

9. A battery pack as claimed in claim 8, wherein the sliding mechanism comprises a first sliding groove arranged along the longitudinal direction on the outer surfaces of the pair of frame wall portions of the frame body, and a folded piece formed by folding back the edge of the first plate side wall of the first plate portion and insertable into the first sliding groove.

10. A battery pack according to any one of claims 1 to 7, wherein the second connecting structure includes wall protrusions arranged on the second plate side walls of the pair of frame wall portions of the frame body.

11. A battery pack according to any one of claims 1 to 7, wherein the edge of the first plate portion is curved.

12. A battery pack according to any one of claims 1 to 7, wherein the edge of the second plate portion is curved.

13. A method for manufacturing a battery pack including a secondary battery cell having a cell first main surface, a cell second main surface opposite the cell first main surface, and a pair of cell side surfaces connecting the cell first main surface and the cell second main surface, a resin frame body having a pair of frame wall portions covering at least the pair of cell side surfaces of the secondary battery cell, a metal first plate portion fixed to the frame body and covering the cell first main surface of the secondary battery cell, and a metal second plate portion covering the cell second main surface of the secondary battery cell, the method comprising: a step of sliding the first plate portion between the pair of frame wall portions of the frame body to connect the frame body and the first plate portion; a step of inserting the secondary battery cell between the pair of frame wall portions of the frame body and fixing the cell first main surface of the secondary battery cell to the first plate portion via a first adhesive; and a step of fixing the second plate portion to the cell second main surface of the secondary battery cell via fixing means.

14. A method for manufacturing a battery pack as described in claim 13, wherein the step of connecting the frame body and the first plate portion is carried out by bringing a flat first plate insertion end of one of the longitudinal end faces of the first plate portion between first plate side walls, each of which has a bent longitudinal side surface, close to the longitudinal end face of the frame body, and sliding the first plate side wall of the first plate portion against the outer surfaces of the pair of frame wall portions of the frame body.

15. A method for manufacturing a battery pack as described in claim 14, wherein the step of connecting the frame body and the first plate portion is carried out by inserting a folded piece formed by folding back the edge of the first plate side wall of the first plate portion into a first sliding groove formed along the longitudinal direction on the outer surfaces of the pair of frame wall portions of the frame body and sliding the folded piece.

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