Battery and battery manufacturing method

Abstract

The invention relates to a battery and a battery manufacturing method. A battery includes a battery case in which an electrode stack is accommodated, and in which a rectangular opening is formed by a pair of short-side wall portions and a pair of long-side wall portions of the battery case, and at a corner portion of the opening, an electrode stack is accommodated in the battery case. At least one of the short side wall portion or the long side wall portion is bent to form a protruding portion protruding toward an outer side of the battery case.

Description

Technical Field

[0001] This disclosure relates to a battery and a method for manufacturing a battery. Background Technology

[0002] Japanese Patent Application Publication No. 2015-092460 discloses a battery comprising an electrode body and a housing that internally accommodates an electrode stack (electrode body), wherein the walls of the housing are alternately bent inward and outward to provide protrusions projecting into the interior of the housing. In this battery, a plurality of protrusions support linear portions of the electrode body and suppress displacement of the electrode body caused by expansion and contraction during battery charging and discharging. Summary of the Invention

[0003] However, in the technology disclosed in JP-A No. 2015-092460, when the electrode stack is inserted into the housing, the protrusions provided in the wall of the housing and the electrode stack may interfere with each other. Therefore, there is room for improvement in terms of the insertability of the electrode stack into the housing.

[0004] In view of the above, this disclosure provides a battery and a battery manufacturing method that can improve the insertability of the electrode stack into the battery housing and suppress the displacement of the electrode stack housed inside the battery housing.

[0005] The battery of the first aspect of this disclosure includes a battery housing, in which an electrode stack is housed, and in which a rectangular opening is formed by a pair of short sidewalls and a pair of long sidewalls of the battery housing, wherein at the corner of the opening, at least one of the short sidewalls or the long sidewalls is bent to form a protrusion protruding toward the outside of the battery housing.

[0006] The battery of the first aspect includes a battery housing in which a rectangular opening is formed by a pair of short sidewalls and a pair of long sidewalls, and an electrode stack is housed inside the battery housing. In the battery housing, a protrusion is formed at the corner of the opening by bending at least one of the short or long sidewalls. Further, the protrusion is shaped to project outwards from the battery housing. In other words, according to this configuration, the opening of the battery housing has a pre-existing extra length portion for forming the protrusion at the corner of the battery housing. When the electrode stack is inserted into the battery housing through the opening during manufacturing, interference between the opening and the electrode stack is suppressed by the extra length portion prepared before forming the protrusion. The insertability of the electrode stack into the battery housing can be improved. Furthermore, with the electrode stack housed inside the battery housing and the protrusion already formed at the corner of the opening of the battery housing, the extra length portion disappears and the gap between the sidewalls of the battery housing and the electrode stack is reduced. Displacement of the electrode stack housed inside the battery housing can be suppressed.

[0007] The battery of the second aspect of this disclosure is the battery of the first aspect, wherein the inner surfaces of the short sidewall and the long sidewall opposite to the electrode stack are constructed of flat surfaces.

[0008] In the battery of the second aspect, the inner surfaces of the short and long sidewalls facing the electrode stack in the battery casing are constructed of flat surfaces. With the battery casing having protrusions and the gap between the sidewalls of the battery casing and the electrode stack reduced, the surface of the electrode stack abuts against the flat surface, thus dispersing the constraint forces toward the electrode stack. This suppresses the localized constraint forces acting on the surface of the electrode stack.

[0009] The battery of the third aspect of this disclosure is the battery of the first or second aspect, wherein the protrusion protrudes in the stacking direction of the electrode stack.

[0010] In the battery of the third aspect, the protrusion formed at the battery casing protrudes along the stacking direction of the electrode stack. This can improve the constraint on the electrode stack housed inside the battery casing in the stacking direction.

[0011] The battery of the fourth aspect of this disclosure is the battery of the first or second aspect, wherein the protrusion protrudes in a direction perpendicular to the stacking direction of the electrode stack.

[0012] In the battery of the fourth aspect, the protrusion formed at the battery casing protrudes in a direction perpendicular to the stacking direction of the electrode stack. This can improve the constraint on the electrode stack housed inside the battery casing in a direction perpendicular to the stacking direction.

[0013] The battery of the fifth aspect of this disclosure is a battery of any one of the first to fourth aspects, wherein the protrusion protrudes in a direction forming an angle in the range of 25° to 70° relative to the stacking direction of the electrode stack.

[0014] In the battery of the fifth aspect, the protrusion formed at the battery casing protrudes along an angle ranging from 25° to 70° relative to the stacking direction of the electrode stack. Compared to a structure where the protrusion protrudes parallel to the stacking direction, the amount of protrusion in the stacking direction is reduced. The size of the battery casing can be reduced in the stacking direction, thus achieving a reduction in size.

[0015] The battery of the sixth aspect of this disclosure is a battery of any one of the first to fifth aspects, wherein, in the battery casing, a recess is formed in a direction perpendicular to the stacking direction adjacent to the protrusion.

[0016] In the battery of the sixth aspect, a recessed portion in a direction perpendicular to the stacking direction is formed adjacent to a protruding portion in the stacking direction. Compared to a structure without a recess, the additional length at the outer periphery of the opening in the battery casing can be sufficiently ensured. The insertability of the electrode stack into the battery casing can be further improved.

[0017] The battery of the seventh aspect of this disclosure is a battery of any one of the first to sixth aspects, wherein, in the battery casing, a recessed portion in the stacking direction is formed adjacent to a protrusion.

[0018] In the battery of the seventh aspect, a recessed portion in the stacking direction is formed adjacent to a protruding portion in the stacking direction. Compared with a structure without a recess, the additional length of the battery casing can be sufficiently ensured. The insertability of the electrode stack into the battery casing can be further improved.

[0019] The battery of the eighth aspect of this disclosure is a battery of any one of the first to seventh aspects, wherein the wall thickness of the protrusion is less than the wall thickness of the other portions of the short side wall and the long side wall.

[0020] In the battery of the eighth aspect, the wall thickness of the protrusion is configured to be less than the wall thickness of the other portions of the short and long sidewalls of the battery casing. Compared to the case where the thickness of the protrusion is configured to be the same as that of the other portions of the sidewalls of the battery casing, this facilitates the bending of the sidewalls during the formation of the protrusion.

[0021] The battery module of the ninth aspect of this disclosure is a battery module comprising a plurality of batteries according to any one of the first to eighth aspects. The battery module includes: a plurality of battery housings arranged in one direction; an elastic body disposed between the battery housings; and a pair of constraint members constraining the plurality of battery housings from both sides in said one direction, wherein the plurality of battery housings are arranged such that one long side wall of each battery housing is opposite to another long side wall of an adjacent battery housing.

[0022] The battery module of the ninth aspect includes a plurality of battery housings arranged in one direction, an elastomer disposed between the battery housings, and a pair of constraint members constraining the plurality of battery housings from both sides in said one direction. The expansion and contraction of the battery during charging and discharging can be absorbed by the deformation of the elastomer. The plurality of battery housings are arranged in one direction such that one long sidewall of each battery housing faces another long sidewall of an adjacent battery housing. In other words, the constraint pressure applied from the constraint members is input to the plurality of battery housings via the long sidewalls, which are large areas of the battery housings. In this configuration, the battery housings have protrusions at the corners of the openings that project outwards towards the outside of the battery housing, thus reducing the gap between the long sidewalls and the electrode stack. The constraint pressure is effectively applied from the constraint members to the electrode stack.

[0023] The tenth aspect of this disclosure relates to a battery manufacturing method, which is a method of manufacturing a battery including a battery casing, in which an electrode stack is housed, and in which a rectangular opening is formed by a pair of short sidewalls and a pair of long sidewalls of the battery casing, the method comprising: inserting the electrode stack through the opening; and squeezing the battery casing, bending at least one of the short sidewalls or the long sidewalls, and forming a protrusion at the corner of the opening, the protrusion protruding toward the outside of the battery casing.

[0024] In the battery manufacturing method of the tenth aspect, an electrode stack is inserted through a rectangular opening, and thereafter, the battery casing is compressed to form a protrusion at the corner of the opening. In other words, when the electrode stack is inserted, the opening of the battery casing has an additional length portion for forming the protrusion. Interference between the battery casing and the electrode stack is suppressed, and the insertability of the electrode stack into the battery casing is improved. Furthermore, with the electrode stack housed inside the battery casing and the protrusion already formed at the corner of the opening, the gap between the sidewall portion of the battery casing and the electrode stack is reduced. A battery in which displacement of the electrode stack housed inside the battery casing is suppressed can be obtained.

[0025] As described above, the battery and battery manufacturing method disclosed herein can improve the insertability of the electrode stack into the battery housing and suppress the displacement of the electrode stack housed inside the battery housing. Attached Figure Description

[0026] Figure 1 This is a partial exploded perspective view of the battery module in relation to the embodiment;

[0027] Figure 2 This is a perspective view of the battery in relation to the embodiment;

[0028] Figure 3 It is a schematic representation of the path along Figure 2 A cross-sectional view of the electrode stack in the state of line 3-3 cutting the electrode stack;

[0029] Figure 4 It is a schematic representation of the path along Figure 2 A cross-sectional view of the battery casing with line 4-4 showing the state of the battery casing being cut;

[0030] Figure 5 It is a schematic representation of the path along Figure 4 A cross-sectional view of the battery casing with the battery casing cut along line 5-5;

[0031] Figure 6 It is shown by Figure 5 A magnified cross-sectional view of the region P indicated by the two dashed lines of different lengths in the image;

[0032] Figure 7A This is a schematic diagram illustrating a battery manufacturing method according to an embodiment, and shows the step of inserting an electrode stack into a battery casing;

[0033] Figure 7B This is a schematic diagram describing a battery manufacturing method according to an embodiment, and shows the steps of interconnecting the electrode stack and internal terminals;

[0034] Figure 7C This is a schematic diagram describing a battery manufacturing method according to an embodiment, and shows the steps of connecting the housing body of the battery casing to the terminal wall portion.

[0035] Figure 7D The steps of squeezing the battery casing are shown;

[0036] Figure 8 It corresponds to Figure 6 A partially enlarged cross-sectional view is shown, and a first example variant of the battery of the embodiment is also shown;

[0037] Figure 9 It corresponds to Figure 6 A partially enlarged cross-sectional view is shown, and a second example variant of the battery of the embodiment is also shown;

[0038] Figure 10 It corresponds to Figure 6A partially enlarged cross-sectional view is shown, and a third example variant of the battery of the embodiment is illustrated; and

[0039] Figure 11 It corresponds to Figure 6 The image shows a partially enlarged cross-sectional view, and also illustrates a fourth example variant of the battery in the embodiment. Detailed Implementation

[0040] The following will be based on Figures 1 to 7D The following describes a battery module 100 and a battery 10A included in the battery module 100, relating to an embodiment. It should be noted that arrow W1, appropriately shown in the drawings, indicates a first direction, arrow W2 indicates a second direction, and arrow W3 indicates a third direction. The first, second, and third directions are mutually orthogonal. Furthermore, in this embodiment, the first direction W1 aligns with the width direction of the battery 10A. The second direction W2 aligns with the thickness direction of the battery 10A. The third direction W3 aligns with the height direction of the battery 10A.

[0041] It should be noted that, unless otherwise specified in the specification, the number of each element is not limited to one, but can be multiple. Furthermore, in the accompanying drawings, substantially identical elements are assigned the same reference numerals, and redundant descriptions from the specification will be omitted.

[0042] Furthermore, in this specification, the term "step" includes not only steps that are independent of other steps, but also steps that cannot be clearly distinguished from other steps, as long as the intended purpose of the step is achieved. Additionally, unless otherwise stated in this specification, the expression "protruding in one direction" should include cases where something protrudes in a particular direction and cases where something protrudes in different directions at a predetermined angle relative to that particular direction.

[0043] (Battery module)

[0044] Figure 1 This is a partial exploded perspective view of battery module 100. (See attached image.) Figure 1 As shown, the battery module 100 is configured to include a plurality of batteries 10A, an elastic body 12 disposed between the batteries 10A, and a pair of constraint members 14.

[0045] Multiple batteries 10A are arranged along the second direction W2 with their width direction aligned with the first direction W1 and their thickness direction aligned with the second direction W2. The multiple batteries 10A are, for example, lithium-ion secondary batteries and are electrically interconnected via busbars 16. Each battery 10A has a battery housing 40 serving as an external casing member and an electrode stack 20 housed within the battery housing 40. The battery housing 40 and the electrode stack 20 will be described in further detail below.

[0046] Because of the multiple batteries 10A, multiple battery housings 40 are arranged in the battery module 100 along the second direction W2. Furthermore, plate-like or sheet-like elastomers 12 are disposed between the multiple battery housings 40.

[0047] As an example, the elastomers 12 are all formed in the shape of rectangular plates, with their thickness direction aligned with the second direction W2. The elastomers 12 constitute a buffer member that absorbs the expansion and contraction of the battery 10A during charging and discharging. The material of the elastomers 12 is not particularly limited, and known materials such as resins and silicone can be suitably selected. The elastomers 12 can be constructed from one type of these materials, or by layering two or more types of materials. The elastomers 12 are preferably insulators to prevent short circuits between the batteries 10A. Furthermore, the material of the elastomers 12 preferably has excellent thermal insulation properties to prevent heat propagation between the batteries 10A in the event of an anomaly. Examples of thermal insulation members with excellent thermal insulation properties include polyurethane and expandable silicone resin, with expandable silicone resin being preferred, serving as both the elastomer and the thermal insulation member. The elastomer 12 in this embodiment is formed from expandable silicone resin as an example.

[0048] It should be noted that the elastomer 12 is shorter in its width direction (second direction W2) than the battery 10A in its width direction (second direction W2), and the elastomer 12 is positioned away from the width direction end of the battery housing 40. When constructing the battery module 100, the elastomer 12 and the protrusion 50 of the battery housing 40, described later, do not interfere with each other.

[0049] A pair of constraint members 14, also referred to as end plates, are disposed on both sides of a stack in the second direction W2 of the stack in which the plurality of batteries 10A and elastomers 12 are stacked together. The pair of constraint members 14 are rectangular plate-shaped members, with their width direction aligned with the first direction W1 and their thickness direction aligned with the second direction W2. The pair of constraint members 14 are formed, for example, of resin or metal. The pair of constraint members 14 are interconnected by a pair of side plates 18 extending along the second direction W2.

[0050] A pair of side plates 18 are provided, for example, on both sides of a stack in which a plurality of batteries 10A, an elastomer 12 and a pair of restraining members 14 are stacked together along a first direction W1. The pair of side plates 18 are members that interconnect a pair of restraining members 14 in a second direction W2, and the two ends of the side plates 18 in the second direction W2 are fastened to the pair of restraining members 14 by fastening members 4 such as bolts.

[0051] Due to the above configuration, in the battery module 100, a plurality of battery housings 40 arranged along the second direction W2 are constrained from both sides of the second direction W2 by a pair of constraint members 14. A predetermined constraint pressure is applied to each battery housing 40 along the second direction W2. The detailed configuration of the battery 10A will now be described below.

[0052] (Battery)

[0053] Figure 2 This is a perspective view of the battery 10A in the embodiment. Figure 4 It is schematically shown that along Figure 2 Line 4-4 shows a cross-sectional view of the battery casing 40 in its cut state. Figure 2 As shown, the battery 10A is configured to include an electrode stack 20 configured as a positive electrode and a negative electrode, and a battery casing 40 that houses the electrode stack 20.

[0054] (Electrode stack)

[0055] Figure 3 It is schematically shown that along Figure 2 Line 3-3 shows a cross-sectional view of the electrode stack 20 in the state of being cut. (See figure 3-3.) Figure 3 As shown, the electrode stack 20 has an electrode body 21, multiple positive current collector terminals 22, and multiple negative current collector terminals 23. The electrode body 21 includes multiple unit electrode bodies 21U. The multiple unit electrode bodies 21U are stacked along the second direction W2. The multiple unit electrode bodies 21U are electrically connected in parallel.

[0056] As an example, the electrode body 21 is formed in the shape of a rectangular plate, with its width direction aligned with the first direction W1 and its thickness direction aligned with the second direction W2. Multiple positive current collector terminals 22 protrude from one side of the electrode body 21 in the first direction W1. Multiple negative current collector terminals 23 protrude from the other side of the electrode body 21 in the first direction W1.

[0057] The stacked structure of the unit electrode body 21U is a unipolar structure. Specifically, each unit electrode body 21U has two solid electrolyte layers 211, two positive electrode active material layers 212, two negative electrode active material layers 213, two positive electrode current collectors 214, and one negative electrode current collector 215. The positive electrode current collector 214, positive electrode active material layer 212, solid electrolyte layer 211, negative electrode active material layer 213, negative electrode current collector 215, negative electrode active material layer 213, solid electrolyte layer 211, positive electrode active material layer 212, and positive electrode current collector 214 are stacked sequentially along the second direction W2.

[0058] A positive current collector terminal 22 is connected to a positive current collector 214. A negative current collector terminal 23 is connected to a negative current collector 215. The number of positive current collector terminals 22 in the electrode stack 20 is greater than the number of negative current collector terminals 23 in the electrode stack 20.

[0059] The solid electrolyte layer 211 comprises a solid electrolyte. There are no particular limitations on the solid electrolyte, and it can be an aggregate of multiple particles. Preferably, the solid electrolyte comprises one selected from the group consisting of sulfide solid electrolytes, oxide solid electrolytes, and halide solid electrolytes. The solid electrolyte can be a known solid electrolyte.

[0060] The solid electrolyte may also include a binder. The binder can be used to bond the solid electrolyte together. The binder can be used to bond the solid electrolyte to the positive electrode active material layer 212 or the negative electrode active material layer 213. Examples of binders include vinyl halide resins (e.g., polyvinylidene fluoride (PVdF)), rubbers (e.g., acrylate-butadiene rubber (ABR) or styrene-butadiene rubber (SBR)), or polyolefin resins (e.g., polyethylene (PE) or polypropylene (PP)).

[0061] The positive electrode active material layer 212 contains a positive electrode active material. The positive electrode active material layer 212 may also contain at least one of a solid electrolyte, a conductive additive, and a binder for the positive electrode, as needed.

[0062] The positive electrode active material layer 212 preferably comprises a lithium composite oxide as the positive electrode active material. The lithium composite oxide may contain at least one type selected from the group consisting of F, Cl, N, S, Br, and I. Furthermore, the lithium composite oxide may have a crystal structure belonging to at least one space group selected from the space groups R-3m, Immm, and P63-mmc. Additionally, the dominant array of transition metals, oxygen, and lithium in the lithium composite oxide may have an O2 structure. The positive electrode active material may be a known positive electrode active material.

[0063] Examples of solid electrolytes used for the positive electrode include the same solid electrolytes as those exemplified as solid electrolytes included in a solid electrolyte layer.

[0064] Examples of conductive additives include carbon materials (e.g., carbon black, carbon nanotubes, graphite, or fluorinated carbon), metallic materials (e.g., aluminum powder or conductive whiskers), or conductive polymer materials (e.g., polyaniline, polypyrrole, or polythiophene).

[0065] Examples of adhesives include the same adhesives as those exemplified as those included in a solid electrolyte layer.

[0066] The negative electrode active material layer 213 contains a negative electrode active material. The negative electrode active material layer 213 may also contain at least one of a solid electrolyte, a conductive additive, and a binder for the negative electrode, as needed.

[0067] Examples of negative electrode active materials include Li-based active materials (e.g., lithium metal), carbon-based active materials (e.g., graphite), oxide-based active materials (e.g., lithium titanate), or Si-based active materials (e.g., elemental Si).

[0068] Examples of solid electrolytes used for the negative electrode include the same solid electrolytes exemplified as those used for the positive electrode in the active material layer of the positive electrode.

[0069] Examples of conductive additives that can be used in the negative electrode active material layer include the same conductive additives exemplified as those that can be used in the positive electrode active material layer.

[0070] Examples of binders that can be used in the negative electrode active material layer include the same binders exemplified as those that can be used in the positive electrode active material layer.

[0071] The positive current collector 214 collects current from the positive active material layer 212. The material of the positive current collector is not particularly limited, and examples include stainless steel, aluminum, copper, nickel, iron, titanium, or carbon. The positive current collector can be an aluminum alloy foil or aluminum foil. Aluminum alloy foil and aluminum foil can be manufactured using powder. The shape of the positive current collector is, for example, foil or mesh. The positive current collector can have a structure in which a buffer layer, an elastic layer, or a positive temperature coefficient (PTC) thermistor layer is disposed on its surface.

[0072] The negative current collector 215 collects current from the negative active material layer 213. The material of the negative current collector is not particularly limited, and examples include stainless steel, aluminum, copper, nickel, iron, titanium, or carbon. The negative current collector can be copper foil. The shape of the negative current collector is, for example, foil or mesh. The negative current collector can have a structure in which a buffer layer, an elastic layer, or a positive temperature coefficient (PTC) thermistor layer is disposed on its surface.

[0073] The positive current collector tab 22 electrically interconnects the positive current collector 214 and the positive terminal 26. The positive current collector tab 22 is connected to the positive current collector 214. The positive current collector tab 22 protrudes to one side of the electrode body 21 in the width direction (first direction W1). Specifically, a bundle comprising multiple positive current collector tabs 22 is electrically connected to the positive terminal 26. The positive current collector tabs 22 are preferably formed continuously from the positive current collector 214. The material of the positive current collector tab is not particularly limited and can be a metal (e.g., aluminum, stainless steel (SUS), or nickel).

[0074] The negative current collector terminal 23 electrically interconnects the negative current collector 215 and the negative terminal 28. The negative current collector terminal 23 is connected to the negative current collector 215. The negative current collector terminal 23 protrudes to the opposite side in the width direction (first direction W1) of the electrode body 21. Specifically, a bundle comprising a plurality of negative current collector terminals 23 is electrically connected to the negative terminal 28. The negative current collector terminals 23 are preferably formed continuously from the negative current collector 215. The material of the negative current collector terminals is not particularly limited and can be a metal (e.g., aluminum, stainless steel (SUS), or nickel).

[0075] The electrode stack 20 having the above-described structure is in a state where a pair of resin sheets 30 serving as insulating members are disposed on two side surfaces of the electrode stack 20 along the second direction W2 (see [reference]). Figure 5 It is located inside the battery housing 40.

[0076] The materials used for resin sheets include known resins (e.g., thermoplastic or thermosetting resins). Thermoplastic resins can be elastomers.

[0077] The resin sheet may also contain thermally conductive fillers as needed. There are no particular limitations on the material of the thermally conductive filler, and examples include metal oxides (e.g., aluminum oxide, silicon dioxide, or magnesium oxide), metal nitrides (e.g., aluminum nitride, silicon nitride, or boron nitride), synthetic diamond, or silicon carbide.

[0078] Depending on the requirements, the resin sheet may also include compounding agents. Examples of compounding agents include fillers, such as glass fibers, carbon fibers and inorganic powders, heat stabilizers, antioxidants, pigments, weather-resistant agents, flame retardants, plasticizers, dispersants, lubricants, mold release agents or antistatic agents.

[0079] Furthermore, the electrode stack 20 having the above-described structure has a pair of resin fillers 32 serving as insulating members, the pair of resin fillers 32 being disposed on two side surfaces of the electrode stack 20 in the third direction W3 (see [link to documentation]). Figure 4 ).

[0080] Examples of resin filler materials include those identical to those exemplified as resin sheet 30. The resin filler material may be the same as or different from the resin sheet material.

[0081] As the content of thermally conductive filler increases, the thermal conductivity tends to increase, while the electrical insulation rate tends to decrease. The thermal conductivity of resin filler 32 can be higher than that of resin sheet 30, and the electrical insulation rate of resin filler 32 can be lower than that of resin sheet 30.

[0082] The resin sheet 30 and resin filler 32 are disposed between the battery housing 40 and the electrode stack 20, with the electrode stack 20 housed inside the battery housing 40. The battery housing 40 and the electrode stack 20 are electrically insulated from each other by the resin sheet 30 and resin filler 32.

[0083] (Battery casing)

[0084] Figure 4 It is a schematic representation of the path along Figure 2 Line 4-4 shows a cross-sectional view of the battery casing 40 in its cut state. Figure 4 As shown, the battery casing 40 is configured to include a casing body 42 forming a cylindrical outer shell and a pair of terminal walls 44 sealing two openings in the casing body 42. The casing body 42 and the pair of terminal walls 44 are formed, for example, from a metal plate, such as an aluminum or iron plate.

[0085] The housing body 42 has a pair of short sidewalls 421 facing each other in the third direction W3 and a pair of long sidewalls 422 facing each other in the second direction W2, and the pair of short sidewalls 421 and the pair of long sidewalls 422 form a rectangular opening 43. The rectangular opening 43 constitutes two surfaces facing each other in the housing body 42 along the first direction W1.

[0086] The pair of short sidewalls 421 form the top and bottom surfaces of the battery casing 40, and extend such that their longitudinal direction aligns with the first direction W1 and their transverse direction aligns with the second direction W2. For this purpose, they form two edges on the short side of each opening 43 of the casing body 42.

[0087] A pair of long sidewall portions 422 form two side surfaces (front and rear) of the battery housing 40 in the thickness direction, and extend such that their longitudinal direction is aligned with the first direction W1 and their transverse direction is aligned with the third direction W3. They form two edges on the long side of each opening 43 of the housing body 42.

[0088] The housing body 42 can be formed, for example, by extruding aluminum, or by bending a pair of flat plates using a forming press and then welding the ends of the flat plates together to form a cylindrical housing.

[0089] In this embodiment, the inner surfaces of the short sidewall portion 421 and the long sidewall portion 422 opposite to the electrode stack 20 are composed of flat surfaces.

[0090] Positive terminal 26 and negative terminal 28, which serve as electrode terminals, are disposed on a pair of terminal walls 44. Each terminal wall 44 is formed in the shape of a rectangular plate, the thickness direction of which is aligned with the first direction W1 and has a through hole (not specified in the figure), through which the positive external terminal 26B and the negative external terminal 28B, described later, are inserted.

[0091] The positive terminal 26 includes an internal positive terminal 26A located inside the battery housing 40 and an external positive terminal 26B located outside the battery housing 40. The internal positive terminal 26A is formed into a rectangular plate whose thickness direction is aligned with the first direction W1, and is disposed along the inner surface of the terminal wall portion 44. The positive current collector tab 22 of the electrode stack 20 is electrically connected to the internal positive terminal 26A. Furthermore, the internal positive terminal 26A has a through hole (not specified in the drawings), through which the external positive terminal 26B is inserted.

[0092] The positive external terminal 26B is, for example, made of metal rivets. The positive external terminal 26B is fixed by inserting it into a through hole passing through the terminal wall 44 and the positive internal terminal 26A, and deforming the axial end of the positive external terminal 26B. In other words, the positive external terminal 26B is fixed to the terminal wall 44 and the positive internal terminal 26A by forging.

[0093] In addition, an insulating member 34 is located between the terminal wall portion 44 of the battery housing 40 and the positive terminal 26 to electrically insulate the battery housing 40 from the positive terminal 26.

[0094] The negative terminal 28 includes an internal negative terminal 28A located inside the battery housing 40 and an external negative terminal 28B located outside the battery housing 40. The negative current collector 23 of the electrode stack 20 is electrically connected to the internal negative terminal 28A. The construction of the negative terminal 28 is the same as that of the positive terminal 26, therefore a detailed description will be omitted.

[0095] here, Figure 5 It is a schematic representation of the path along Figure 4 A cross-sectional view of the battery casing 40, showing the state of the casing 40 cut along line 5-5. Furthermore, Figure 6 It is shown by Figure 5 The magnified cross-sectional view of the region P indicated by the long and short dashed lines in the image.

[0096] (convex part)

[0097] like Figure 5 and Figure 6As shown, in the battery housing 40, a protrusion 50 protruding towards the outside of the battery housing 40 is formed in the corner 43A of the opening 43. The protrusion 50 is formed by bending at least one of the short side wall portion 421 and the long side wall portion 422, and is formed by pressing the housing body 42 of the battery housing 40 as described below.

[0098] like Figure 6 As shown, as an example, the protrusion 50 can protrude from the long side wall portion 422 of the battery housing 40 along the second direction W2. That is, the protrusion 50 can protrude in the stacking direction of the electrode stack 20. The protrusion 50 is formed by bending the end of the long side wall portion 422 corresponding to the corner portion 43A into a generally U-shaped shape that protrudes in the second direction W2. The protrusion 50 together with the short side wall portion 421 of the housing body 42 forms a flat surface. Furthermore, the protrusion 50 is integrally formed by bending the end of the long side wall portion 422 of the housing body 42 into a generally right angle. The constraint on the electrode stack housed inside the battery housing 40 can be improved in the stacking direction.

[0099] More specifically, the protrusion 50 has a first side surface 50A disposed on one side of the top 52 and continuous with the short side wall portion 421 of the housing body 42, and a second side surface 50B disposed on the other side of the top 52 and continuous with the long side wall portion 422 of the housing body 42. In this embodiment, the angle formed by the first side surface 50A and the stacking direction (second direction W2) of the electrode stack 20 is 0°. Furthermore, the angle formed by the second side surface 50B and the stacking direction of the electrode stack 20 is also 0°. In other words, the protrusion 50 protrudes parallel to the stacking direction of the electrode stack 20.

[0100] In addition, such as Figure 6 As shown in the enlarged view, the thickness T2 of the protrusion 50 is configured to be less than the thickness T1 of the other parts of the short side wall 421 and the long side wall 422. When the housing body 42 is bent by extrusion, the bending of the protrusion 50 can be performed more easily than the bending of the other parts of the short side wall 421 and the long side wall 422.

[0101] Here, in Figure 6 In the diagram, the outline of the housing body 42 before the formation of the protrusion 50 is indicated by one long and two short dashed lines. (See diagram for example.) Figure 6 As shown, in the housing body 42, before the protrusion 50 is formed, the cross-sectional area of ​​the opening 43 is designed to be sufficiently larger than the cross-sectional area obtained by cutting the electrode stack 20 (electrode body 21) along the second direction W2. In other words, before the protrusion 50 is formed, an additional length portion is provided on the outer periphery of the opening 43. Therefore, when the electrode stack 20 is inserted into the housing body 42 in this state, interference between the housing body 42 and the electrode stack 20 is suppressed.

[0102] like Figure 6 As shown by the solid line, with the protrusion 50 already formed in the corner 43A of the opening 43, the extra length portion on the outer periphery of the opening 43 disappears, and the gap between the sidewall portion of the housing body 42 and the electrode stack 20 decreases. The electrode stack 20 is well constrained inside the battery housing 40.

[0103] In particular, when the electrolyte layer is constructed to include a solid electrolyte as in the electrode stack 20 of this embodiment, the construction of this embodiment is more advantageous in improving the ability to confine the electrode stack 20 within the battery housing 40. In other words, it is known that when the electrolyte layer is constructed to include a solid electrolyte, the amount of expansion and contraction of the battery during charging and discharging is smaller compared to a secondary battery using a liquid electrolyte. Therefore, if the dimensional tolerances of the battery housing are determined with preference for the insertability of the electrode stack 20, the gap between the sidewall portion of the housing body and the electrode stack increases, which may lead to displacement within the battery housing. Conversely, in this embodiment, the dimensional tolerances (extra length portion) of the housing body 42 can be increased when the electrode stack 20 is inserted, and the dimensional tolerances (extra length portion) of the housing body 42 can be decreased after the electrode stack 20 is inserted. This effectively improves the ability to confine the electrode stack within the battery housing in an all-solid-state battery.

[0104] [Battery Manufacturing Method]

[0105] The battery manufacturing method relating to this embodiment will now be described below with reference to FIG7. The battery manufacturing method of this embodiment is, for example, a method for manufacturing a battery 10A. The battery manufacturing method includes a preparation step, an insertion step, a resin filling step, a terminal connection step, a sealing step, and an extrusion step.

[0106] (Preparation steps)

[0107] The preparation step involves attaching a pair of resin sheets 30 to two side surfaces of the electrode stack 20 along the second direction W2. The method of attaching the resin sheets 30 is not particularly limited and can be any known method.

[0108] (Insert steps)

[0109] The insertion step is the step of inserting the electrode stack 30 into the housing body 42 through the opening 43. Figure 7A Since this step is performed before the protrusion 50 is formed on the housing body 42, the electrode stack 20 is inserted into the housing body 42 through the opening 43 which does not have the protrusion 50.

[0110] (Resin filling step)

[0111] The resin filling step is the step of filling the gap between the short sidewall 421 of the housing body 42 and the electrode stack 20 with uncured resin filler 32 to form resin filler 32. There are no particular limitations on the method of filling the gap with resin filler 32, and any known method may be used. The method for curing the uncured resin filler 32 is appropriately selected depending on the type of resin.

[0112] (Terminal connection steps)

[0113] The terminal connection step involves connecting multiple positive current collector terminals 22 and positive terminals 26 to each other, and connecting multiple negative current collector terminals 23 and negative terminals 28 to each other. Figure 7B Specifically, the positive current collector terminal 22 is connected to the positive internal terminal 26A, and the negative current collector terminal 23 is connected to the negative internal terminal 28A. The connection method is not particularly limited and can be any known method. In this embodiment, the connection is made by soldering.

[0114] In this step, the positive external terminal 26B and the negative external terminal 28B are connected together with the insulating member 34 to the positive current collector terminal 22 and the negative current collector terminal 23, respectively.

[0115] (Sealing Step)

[0116] The sealing step is the step of attaching a pair of terminal wall portions 44 to the opening 43 of the housing body 42 to seal the opening 43. Figure 7C The sealing method is not particularly limited and can be any known method. In this embodiment, the seal is achieved by welding.

[0117] (Extrusion step)

[0118] The extrusion step is the step of extruding the battery casing 40 to form a protrusion 50 at the corner 43A of the opening 43. This step can be achieved by extruding the battery casing 40 on both thickness direction (second direction W2) sides by a first mold 60 and on both height direction (third direction W3) sides by a second mold 62. At this time, a gap 64 between the first mold 60 and the second mold 62 is provided at a position corresponding to the corner 43A of the battery casing 40. In this state, when the battery casing 40 is extruded in the thickness and height directions, the extra length portion on the outer periphery of the opening 43 gathers at the gap 64, thereby forming a protrusion 50 corresponding to the shape of the gap 64.

[0119] (Actions and effects)

[0120] As described above, the battery 10A of this embodiment includes a battery housing 40, in which a rectangular opening 43 is formed by a pair of short sidewalls 421 and a pair of long sidewalls 422, and an electrode stack 20 is housed inside the battery housing 40. A protrusion 50, formed by bending at least one of the short sidewalls 421 and the long sidewalls 422, is formed at the corner 43A of the opening 43. Furthermore, the protrusion 50 has a shape that protrudes outward toward the outside of the battery housing 40. In other words, according to this configuration, the opening 43 of the battery housing 40 is pre-formed with an additional length portion for forming the protrusion 50 at the position of the corner 43A of the battery housing 40. Figure 7B As shown, during the manufacturing process, in the step of inserting the electrode stack 20 into the housing body 42 through the opening 43 of the housing body 42, interference between the opening 43 of the housing body 42 and the electrode stack 20 is suppressed by an additional length portion prepared before forming the protrusion 50. This improves the insertability of the electrode stack 20 into the battery housing 40. Furthermore, with the electrode stack 20 housed inside the battery housing 40 and the protrusion 50 already formed at the corner 43A of the opening 43, the additional length portion disappears, and the gap between the sidewall of the battery housing 40 and the electrode stack 20 is reduced. This suppresses displacement of the electrode stack 20 housed inside the battery housing 40.

[0121] Furthermore, in the battery housing 40, the inner surfaces of the short sidewall portion 421 and the long sidewall portion 422, which face the electrode stack 20, are constructed as flat surfaces. With the battery housing 40 having the protrusion 50 and the gap between the sidewall portion of the battery housing 40 and the electrode stack 20 reduced, the surface of the electrode stack 20 abuts against this flat surface, thus dispersing the constraint force. This suppresses the localized constraint force acting on the surface of the electrode stack 20.

[0122] Furthermore, the protrusion 50 formed on the battery housing 40 protrudes along the stacking direction (second direction W2) of the electrode stack 20. This can improve the constraint on the electrode stack 20 housed inside the battery housing 40 in the stacking direction.

[0123] In addition, such as Figure 6 As shown, the thickness T2 of the protrusion 50 is configured to be less than the thickness T1 of the other portions of the short sidewall portion 421 and the long sidewall portion 422 of the battery housing 40. Compared to the case where the thickness of the protrusion is configured to be the same as the thickness of the other portions of the sidewall portion of the battery housing 40, this can promote the bending of the sidewall portion when forming the protrusion.

[0124] Furthermore, when the battery module 100 is composed of multiple batteries 10A, the battery module 100 is configured to include multiple battery housings 40 arranged along a second direction W2 (a single direction), an elastic body 12 disposed between the battery housings 40, and a pair of constraint members 14 constraining the multiple battery housings 40 from both sides in the second direction W2. The expansion and contraction of the batteries 10A during charging and discharging can be controlled by the elastic body 12 (… Figure 1 It absorbs through deformation.

[0125] Multiple battery housings 40 are arranged along a second direction W2 such that one long sidewall portion 422 of each battery housing 40 is opposite to another long sidewall portion 422 of an adjacent battery housing 40. In other words, the constraint pressure applied from a pair of constraint members 14 is input to the multiple battery housings 40 via the long sidewall portion 422, which is a large area portion of the battery housing 40. In this configuration, the housing body 42 of the battery housing 40 has a protrusion 50 protruding outward from the corner 43A of the opening 43 towards the outside of the battery housing 40, thereby reducing the gap between the long sidewall portion 422 and the electrode stack 20. The constraint pressure is effectively applied to the electrode stack 20 from the constraint members 14.

[0126] The embodiments of this disclosure have been described above, but this disclosure is not limited to the construction of the above embodiments. For example, the shape of the protrusion formed at the corner of the battery casing 40 is not limited to the construction of the above embodiments. Hereinafter, several exemplary variations applicable to the above embodiments will be listed and described. It should be noted that in each exemplary variation, the same components as in the above embodiments will be assigned the same reference numerals, and their descriptions will be omitted.

[0127] (First example variant)

[0128] Now refer to Figure 8 Describe the battery 10B with respect to the first example variant. Figure 8 It corresponds to Figure 6 A partially enlarged cross-sectional view is shown, including an enlarged view of the cross-section of corner 43A of the battery casing 40. (See attached image.) Figure 8 As shown, a protrusion 70 is formed at the corner 43A of the opening 43 of the battery casing 40, and the protrusion 70 protrudes in a direction perpendicular to the stacking direction (third direction W3) of the electrode stack 20. The protrusion 70 is formed by bending the end of the short side wall portion 421 corresponding to the corner 43A into a generally U-shape protruding in the third direction W3. The protrusion 70 and the long side wall portion 422 of the casing body 42 together form a flat surface. Furthermore, the protrusion 70 is integrally formed by bending the end of the short side wall portion 421 of the casing body 42 into a generally right angle.

[0129] More specifically, the protrusion 70 has a first side surface 70A provided on one side of the top 72 and continuous with the short side wall portion 421 of the housing body 42, and a second side surface 70B provided on the other side of the top 72 and continuous with the long side wall portion 422 of the housing body 42. The angle formed by the first side surface 70A and the stacking direction (second direction W2) of the electrode stack 20 is 90°. Furthermore, the angle θ1 formed by the second side surface 70B and the stacking direction of the electrode stack 20 is also 90°. The protrusion 70 protrudes in a direction parallel to and perpendicular to the stacking direction of the electrode stack 20.

[0130] The battery 10B of the first example variant basically follows the construction of the battery 10A of the above embodiment, and thus the same operation and effects can be obtained. Furthermore, in this example variant, the protrusion 70 formed in the battery housing 40 protrudes in a direction perpendicular to the stacking direction of the electrode stack 20 (third direction W3). This improves the constraint on the electrode stack 20 housed inside the battery housing 40 in the direction perpendicular to the stacking direction.

[0131] (Second example variant)

[0132] Now refer to Figure 9 The description relates to battery 10C in connection with the second example variant. Figure 9 It corresponds to Figure 6 A partially enlarged cross-sectional view is shown, including an enlarged view of the cross-section of corner 43A of the battery casing 40. (See attached image.) Figure 9 As shown, a protrusion 80 is formed at the corner 43A of the opening 43 of the battery housing 40, and the protrusion 80 protrudes in a direction that forms a predetermined angle with the stacking direction of the electrode stack 20. The angle formed between the protruding direction of the protrusion 80 and the stacking direction of the electrode stack 20 is preferably set in the range of 25° to 70°, and in this example variant, it is set to 45° as an example.

[0133] The protrusion 80 protrudes along the stacking direction (second direction W2) of the electrode stack 20. The protrusion 80 is formed by bending the end of the long side wall portion 422 corresponding to the corner portion 43A into a generally U-shape protruding along the second direction W2. Therefore, the protrusion 80 together with the short side wall portion 421 of the housing body 42 forms a flat surface. Furthermore, the protrusion 80 is integrally formed by bending the end of the long side wall portion 422 of the housing body 42 into an angle corresponding to the protruding direction of the protrusion 80.

[0134] More specifically, the protrusion 80 has a first side surface 80A provided on one side of the top 82 and continuous with the short side wall portion 421 of the housing body 42, and a second side surface 80B provided on the other side of the top 82 and continuous with the long side wall portion 422 of the housing body 42. The angle formed by the first side surface 80A and the stacking direction (second direction W2) of the electrode stack 20 is 0°. At the same time, the angle θ2 formed by the second side surface 80B and the stacking direction of the electrode stack 20 is 45°. Therefore, the protrusion 80 protrudes in a direction that forms a 45° angle with respect to the stacking direction of the electrode stack 20.

[0135] The battery 10C of the second example variant basically follows the construction of the battery 10A of the above embodiment, and therefore, the same operation and effects can be obtained. Furthermore, the second side surface 80B of the protrusion 80 protrudes in a direction forming an angle in the range of 25° to 70° relative to the stacking direction of the electrode stack 20. Compared to a construction where the protrusion protrudes parallel to the stacking direction, the amount of protrusion in the stacking direction is reduced. The size of the battery casing can be reduced in the stacking direction (second direction W2), and thus, a size reduction can be achieved.

[0136] (Third example variant)

[0137] Now refer to Figure 10 Describe the battery 10D with respect to the third example variant. Figure 10 It corresponds to Figure 6 A partially enlarged cross-sectional view is shown, including an enlarged view of the cross-section of corner 43A of the battery casing 40. (See attached image.) Figure 10 As shown, a protrusion 90 is formed at the corner 43A of the opening 43 of the battery housing 40, and the protrusion 90 protrudes in a direction that forms a predetermined angle with the stacking direction of the electrode stack 20. The angle formed between the protruding direction of the protrusion 90 and the stacking direction of the electrode stack 20 is preferably set in the range of 25° to 70°, and in this example variant, it is set to 70° as an example.

[0138] The protrusion 90 protrudes along the stacking direction (second direction W2) and perpendicular to the stacking direction (third direction W3) of the electrode stack 20. The protrusion 90 is formed by bending the ends of the long side wall portion 422 and the short side wall portion 421 corresponding to the corner portion 43A into a generally U-shape protruding along the second direction W2 and the third direction W3. In the short side wall portion 421 of the housing body 42, a recess 94 is formed adjacent to the protrusion 90 in a direction perpendicular to the stacking direction. Furthermore, the protrusion 90 is integrally formed by bending the end of the long side wall portion 422 of the housing body 42 at an angle corresponding to the protruding direction of the protrusion 90.

[0139] More specifically, the protrusion 90 has a first side surface 90A provided on one side of the top 92 and continuous with the short side wall portion 421 of the housing body 42, and a second side surface 90B provided on the other side of the top 92 and continuous with the long side wall portion 422 of the housing body 42. The first side surface 90A together with the short side wall portion 421 forms a recess 94. The second side surface 90B is inclined in a direction forming an angle θ3 or 70° with respect to the stacking direction of the electrode stack 20. The protrusion 90 protrudes in a direction forming an angle of 70° with respect to the stacking direction of the electrode stack 20.

[0140] The battery 10D of the third example variant basically follows the construction of the batteries 10A and 10C of the above-described embodiments and the second example variants, thus achieving the same operation and effects. Furthermore, in this example variant, a recess 94 recessed in a direction perpendicular to the stacking direction (third direction W3) is formed adjacent to a protrusion 90 protruding in the stacking direction. Compared to a construction without the recess 94, the additional length on the outer periphery can be sufficiently ensured in the opening 43 of the battery housing 40 before the protrusion 90 is formed. The insertability of the electrode stack 20 into the battery housing 40 can be further improved.

[0141] (Fourth example variation)

[0142] Now refer to Figure 11 Describe the battery 10E with respect to the fourth example variant. Figure 11 It corresponds to Figure 6 A partially enlarged cross-sectional view is shown, including an enlarged view of the cross-section of corner 43A of the battery casing 40. (See attached image.) Figure 11 As shown, the protrusion 110 is formed at the corner 43A of the opening 43 of the battery housing 40, and similar to the protrusion 50 in the above embodiment, the protrusion 110 protrudes parallel to the stacking direction of the electrode stack 20.

[0143] In the long side wall portion 422 of the housing body 42, a recess 114 is formed adjacent to the protrusion 110 and recessed in the stacking direction (second direction W2). Furthermore, the top 111 of the protrusion 110 is thus provided in a position where the top 111 does not protrude relative to the long side wall portion 422 in the second direction W2.

[0144] The protrusion 110 is formed by bending the end of the long side wall portion 422 corresponding to the corner portion 43A into a generally U-shape protruding along the second direction W2. A recess 114 is provided between the protrusion 110 and the long side wall portion 422, and is formed by bending the end of the long side wall portion 422 into a generally U-shape recessed along the second direction W2. The protrusion 110, together with the short side wall portion 421 of the housing body 42, forms a flat surface. Furthermore, the protrusion 110 and the recess 114 are integrally formed by bending the end of the long side wall portion 422 of the housing body 42 into a generally S-shape.

[0145] The battery 10E of the fourth example variant basically follows the construction of the above embodiment, and therefore the same operation and effects can be obtained. Furthermore, the recess 114 in the stacking direction is formed adjacent to the protrusion 110 in the stacking direction. Compared to a construction without the recess 114, the additional length on the outer periphery can be sufficiently ensured in the opening 43 of the housing body 42 before the protrusion 110 is formed. The insertability of the electrode stack into the battery housing 40 can be further improved.

[0146] Furthermore, in this example variant, by forming a recess 114, the top 111 of the protrusion 110 is positioned in a position where the top 111 does not protrude relative to the long side wall portion 422 in the second direction W2. The size of the battery housing 40 can be reduced in the stacking direction (second direction W2), and thus, a reduction in size can be achieved.

[0147] [Additional Description]

[0148] Although embodiments and several exemplary variations of this disclosure have been described above, their construction can be substituted and changed without departing from the scope of this disclosure. Furthermore, the constructions of the embodiments and exemplary variations can also be combined and applied.

[0149] In the above embodiments and exemplary variations, the electrolyte layer of the electrode stack is described as being constructed to include a solid electrolyte; however, this disclosure is not limited thereto, and the construction of this disclosure can also be applied to batteries that include a liquid electrolyte in the electrolyte layer.

Claims

1. A battery comprising a battery casing, wherein an electrode stack is accommodated within the battery casing, and wherein a rectangular opening is formed in the battery casing through a pair of short sidewalls and a pair of long sidewalls, wherein: At the corner of the opening, at least one of the short side wall portion or the long side wall portion is bent to form a protrusion that protrudes outward toward the outside of the battery casing.

2. The battery according to claim 1, wherein, The inner surfaces of the short sidewall and the long sidewall, which are opposite to the electrode stack, are constructed of flat surfaces.

3. The battery according to claim 1, wherein, The protrusion protrudes in the stacking direction of the electrode stack.

4. The battery according to claim 1, wherein, The protrusion protrudes in a direction perpendicular to the stacking direction of the electrode stack.

5. The battery according to claim 1, wherein, The protrusion protrudes in a direction that forms an angle in the range of 25° to 70° relative to the stacking direction of the electrode stack.

6. The battery according to claim 3, wherein, In the battery casing, a recessed portion is formed adjacent to the protrusion in a direction perpendicular to the stacking direction.

7. The battery according to claim 3, wherein, In the battery casing, a recessed portion is formed adjacent to the protrusion in the stacking direction.

8. The battery according to claim 1, wherein, The wall thickness of the protrusion is less than the wall thickness of the other parts of the short side wall and the long side wall.

9. A battery module comprising a plurality of batteries according to claim 1, the battery module comprising: Multiple battery casings arranged in one direction; An elastomer disposed between the battery casings; as well as A pair of constraint members constrain the plurality of battery casings from both sides in the same direction. The plurality of battery housings are arranged such that one long side wall portion of each battery housing faces another long side wall portion of an adjacent battery housing.

10. A method of manufacturing a battery, the battery comprising a battery casing, an electrode stack being housed within the battery casing, and a rectangular opening being formed therein by a pair of short sidewalls and a pair of long sidewalls of the battery casing, the method comprising: Insert the electrode stack through the opening; as well as The battery casing is squeezed to bend at least one of the short side wall or the long side wall, and a protrusion is formed at the corner of the opening, the protrusion protruding toward the outside of the battery casing.

Images