Secondary battery manufacturing method and secondary battery
By using the collector terminal of the plate-shaped electrode joint and the method of folding back the tab group multiple times, the problems of high manufacturing cost and limited capacity of existing secondary batteries are solved, and efficient battery manufacturing and capacity increase are achieved.
Patent Information
- Application Number
- CN202510165784.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-04-26
- Filing Date
- 2025-02-14
- Publication Date
- 2025-10-28
AI Technical Summary
The battery terminal structure of existing secondary batteries requires multiple parts to be joined, resulting in high manufacturing costs and limited battery capacity.
The collector terminal with a plate-shaped electrode joint is used to directly join the tab group to the battery terminal through ultrasonic welding, and the tab group is folded back multiple times during the alignment process to increase the battery capacity.
The number of parts and processing costs are reduced, the battery capacity is increased without increasing equipment costs, and efficient battery manufacturing is achieved.
Smart Images
Figure CN120854854A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for manufacturing a secondary battery and to a secondary battery. Background Art
[0002] Conventional secondary batteries used in electric vehicles, such as electric cars, which are driven by motors, include electrode bodies, a housing that contains the electrode bodies, and battery terminals that are mounted in the housing and electrically connected to the electrode bodies. As such a secondary battery with electrode bodies, a battery manufactured, for example, using the method disclosed in Patent Document 1, has been proposed.
[0003] The battery terminal of the battery described in Patent Document 1 is composed of a first current collector and a second current collector. The tabs extending from the electrode body are connected to the second current collector in a bent state, and the second current collector is welded to the first current collector.
[0004] Existing technical documents
[0005] Patent Literature
[0006] Patent Document 1: International Publication No. 2021 / 060009 Summary of the Invention
[0007] Problems to be solved by the invention
[0008] However, in the battery disclosed in Patent Document 1, the equipment cost and parts processing cost are increased because a process of joining the first current collector and the second current collector is required. Furthermore, the parts cost is increased because the second current collector has recesses and through holes required for welding. Moreover, due to the overlap of the joint between the first and second current collectors, the volume occupied by the electrodes in the casing is correspondingly smaller. Thus, the battery disclosed in Patent Document 1, due to its larger number of parts, has room for improvement in manufacturing cost and battery capacity.
[0009] The present invention was made in view of the above-mentioned actual situation, and its object is to provide a method for manufacturing a secondary battery and a secondary battery that can increase battery capacity while suppressing the manufacturing cost caused by the increase in the number of parts.
[0010] Methods used to solve problems
[0011] The manufacturing method of the secondary battery of the present invention for achieving the above-mentioned objectives is characterized by comprising a casing having an opening, a cover installed on the opening of the casing, a flat electrode body formed by stacking positive and negative electrode components separated by a separator, and a positive and negative battery terminal respectively installed on the cover; the electrode body extends from one end face in a second direction orthogonal to the thickness direction of the electrode body, forming a strip-shaped positive electrode tab assembly formed by stacking the tabs of the positive electrode components, and extends from the other end face in the second direction, forming a strip-shaped negative electrode tab assembly formed by stacking the tabs of the negative electrode components; the positive and negative battery terminals have current collector terminals, the current collector terminals including a plate-shaped electrode joint portion disposed between each end face of the electrode body in the second direction and the casing along the end face of the electrode body; The surface of the electrode joint that faces the aforementioned housing is the joint surface; the manufacturing method of the aforementioned secondary battery includes: a joining step, in which the downstream side of the aforementioned positive electrode tab group in the extending direction is joined with the aforementioned joint surface of the aforementioned current collector terminal in the aforementioned positive electrode battery terminal, and the downstream side of the aforementioned negative electrode tab group in the extending direction is joined with the aforementioned joint surface of the aforementioned current collector terminal in the aforementioned negative electrode battery terminal; and an alignment step, in which, after the aforementioned joining step, the aforementioned positive electrode terminal and the aforementioned negative electrode terminal and the aforementioned electrode body are moved relative to each other along the aforementioned first direction, while the aforementioned positive electrode tab group and the aforementioned negative electrode tab group are folded back toward the aforementioned electrode body side at the end of the electrode joint in the aforementioned first direction of the electrode joint along the surface shape of the aforementioned electrode joint of each of the aforementioned current collector terminals, and the aforementioned electrode body is aligned between the aforementioned positive electrode terminal and the aforementioned negative electrode terminal.
[0012] Based on the above-described structural features, since the battery terminal has a current collector terminal including a plate-shaped electrode joint, when the electrode body is installed on the battery terminal, i.e., the current collector terminal, there is no need for a process to join the components constituting the current collector terminal to each other. Furthermore, there is no need for machining such as providing through holes in a portion of the current collector terminal for joining with other components. Therefore, machining costs and equipment costs related to the battery terminal can be reduced, and the manufacturing cost of the secondary battery can be reduced.
[0013] Furthermore, there is no situation where the components constituting the current collector terminals overlap each other, thus preventing the current collector terminals from becoming larger. Therefore, according to the secondary battery manufactured using the above manufacturing method, the battery capacity can be increased by ensuring that the size of the casing is increased without changing the shape of the casing, while ensuring that the dimension of the electrode body in the second direction is longer.
[0014] A further feature of the method for manufacturing the secondary battery of the present invention is that, in the aforementioned alignment process, at least a portion of the aforementioned positive electrode tab assembly and the aforementioned negative electrode tab assembly are arranged to be folded back once or multiple times between each of the aforementioned electrode joints and the end faces of the aforementioned electrode body in the aforementioned second direction for storage.
[0015] Based on the aforementioned structural features, by performing one or more folds in addition to the fold at the end of the electrode joint, multiple folds are made during the alignment process. By performing multiple folds in this alignment process, the inner and outer circumference differences of the tabs constituting each tab assembly during storage can be absorbed while aligning the electrode bodies.
[0016] A further feature of the method for manufacturing the secondary battery of the present invention is that the aforementioned electrode joint is chamfered.
[0017] Based on the above-mentioned structural features, it is possible to suppress damage to the tab assembly when bending the tab assembly along the surface shape of the electrode joint.
[0018] A further feature of the method for manufacturing the secondary battery of the present invention is that the aforementioned engagement surface of the aforementioned electrode joint is inclined such that the distance to the aforementioned electrode body decreases as it moves toward one side of the aforementioned first direction.
[0019] Based on the aforementioned structural features, when each tab assembly is folded back towards the electrode body, it is folded back along the inclined joint surface. Therefore, the flexibility of the tab assembly is improved, allowing it to be housed along the inclined joint surface of the electrode joint. Furthermore, by improving the houseability of the tabs, the size of the electrode body in the first direction can be increased, and higher capacity secondary batteries can be achieved.
[0020] The secondary battery of the present invention is characterized by comprising a casing with an opening, a cover installed in the opening of the casing, a flat electrode body formed by stacking positive and negative electrodes separated by a separator, and a positive battery terminal and a negative battery terminal respectively installed in the cover; the electrode body is housed inside the casing, and a strip-shaped positive electrode tab assembly formed by stacking the tabs of the positive electrode extends from one end face in a second direction orthogonal to the thickness direction of the electrode body (i.e., a first direction), and a strip-shaped negative electrode tab assembly formed by stacking the tabs of the positive electrode extends from the other end face; the positive battery terminal and the negative battery terminal have electrodes... The current collector terminal of the junction; the aforementioned electrode junction is a plate-shaped component disposed between the end face of the aforementioned electrode body and the aforementioned housing in the aforementioned second direction along the end face of the electrode body, and the surface opposite to the aforementioned housing is the junction surface; the aforementioned positive electrode tab group and the aforementioned negative electrode tab group are engaged with the aforementioned junction surfaces of the aforementioned current collector terminals of the aforementioned positive electrode terminal and the aforementioned negative electrode terminal in the downstream direction of the extension direction, and are folded back towards the aforementioned electrode body at the end of the electrode junction in the aforementioned first direction along the surface shape of the aforementioned electrode junction of the aforementioned current collector terminal, and are housed between the aforementioned electrode junction and the end face of the aforementioned electrode body in the aforementioned second direction.
[0021] Based on the above-described structural features, since the battery terminal has a current collector terminal including a plate-shaped electrode joint, when mounting the electrode body on the battery terminal (i.e., the current collector terminal), there is no need for a process to join the components constituting the current collector terminal to each other. Furthermore, there is no need for machining processes such as providing through holes in the current collector terminal for joining with other components. Therefore, for secondary batteries, machining costs and equipment costs related to the battery terminal can be reduced.
[0022] Furthermore, there will be no situation where the components constituting the current collector terminals overlap each other, thus increasing the size of the current collector terminals. Therefore, for secondary batteries, it is possible to increase the battery capacity by increasing the size of the casing without changing its shape, while ensuring that the dimension of the electrode body in the second direction is longer.
[0023] Invention Effects
[0024] As described above, the manufacturing method and secondary battery of the present invention can increase battery capacity while suppressing the increase in the number of parts. Attached Figure Description
[0025] Figure 1 This is an exploded perspective view of the secondary battery according to the first embodiment.
[0026] Figure 2 This is a cross-sectional view showing the general structure of a secondary battery.
[0027] Figure 3 It is a three-dimensional diagram showing a partially unfolded electrode.
[0028] Figure 4 This is a flowchart illustrating the manufacturing method of the secondary battery according to the first embodiment.
[0029] Figure 5 It is a top view used to illustrate the joining process.
[0030] Figure 6 It is a top view used to illustrate the alignment process.
[0031] Figure 7 This is a magnified view showing the state of the electrode body assembled at the collector terminal.
[0032] Figure 8 This is a partial top view of a variation of the first embodiment, Example 1.
[0033] Figure 9 This is a partial top view of a variation of the first embodiment, Example 2.
[0034] Figure 10 This is a partial top view of a variation of the first embodiment, Example 3.
[0035] Figure 11 This is a perspective view of variation 4 of the first embodiment.
[0036] Figure 12 This is a partial side view of a variation of the first embodiment, Example 5.
[0037] Figure 13 This is a top view of the secondary battery according to the second embodiment.
[0038] Figure 14 This is a partial side view of a variation of the second embodiment.
[0039] Figure 15 This is a partial side view showing the collector terminal of the third embodiment. DETAILED DESCRIPTION
[0040] Hereinafter, a secondary battery according to one embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, the following description will use a lithium-ion secondary battery as an example. In order to make the description clearer, the descriptions and drawings will be appropriately simplified.
[0041] [First Embodiment] [Overview of Secondary Battery 1]
[0042] Reference Figure 1 and Figure 2 A general overview of the secondary battery 1 according to this embodiment will be described. Additionally, Figure 1 This is an exploded perspective view of secondary battery 1. Furthermore, Figure 2 This is a cross-sectional view showing the schematic structure of the secondary battery 1 described above. Furthermore, in the following description, the direction parallel to the height direction of the secondary battery 1 is designated as the Z-axis direction, the direction parallel to the winding axis direction of the electrode body 40 is designated as the X-axis direction, and the direction parallel to the thickness direction of the electrode body 40 is designated as the Y-axis direction. The Z-axis direction is parallel to the vertical direction, and the X-axis and Y-axis directions are orthogonal to each other and parallel to the horizontal direction. In this embodiment, the Y-axis direction corresponds to the "first direction," the X-axis direction corresponds to the "second direction," and the Z-axis direction corresponds to the "third direction."
[0043] like Figure 1 and Figure 2 As shown, the secondary battery 1 includes a battery casing 10 consisting of a casing body 11 and a sealing plate 13, battery terminals PS and NS consisting of external terminals 25 and 26 and current collector terminals 27 and 28 mounted on the sealing plate 13, and an electrode body 40 electrically connected to the current collector terminals 27 and 28. The secondary battery 1 is a sealed secondary battery formed by accommodating an electrode body 40 and current collector terminals 27 and 28 inside the casing body 11, sealing the opening of the casing body 11 with the sealing plate 13, and then injecting electrolyte into the casing body 11.
[0044] [Structure of battery casing 10]
[0045] like Figure 1 and Figure 2 As shown, the battery casing 10 of this embodiment consists of a generally rectangular casing body 11 with an opening at the top and a sealing plate 13 that closes the opening of the casing body 11. In the battery casing 10 of this embodiment, both the casing body 11 and the sealing plate 13 are made of aluminum, but are not limited to this. Various metals and alloys can be used as materials for the casing body 11 and the sealing plate 13. In this embodiment, the casing body 11 is equivalent to a "box", and the sealing plate 13 is equivalent to a "cover".
[0046] In this embodiment, the sealing plate 13 has a shape corresponding to the shape of the opening of the housing body 11, and is configured to close the opening of the housing body 11. Specifically, the sealing plate 13 in this embodiment is composed of a flat plate member that is approximately rectangular when viewed from the Z-axis direction. A positive battery terminal PS is provided on one end of the sealing plate 13 in the long side direction (X-axis direction), and a negative battery terminal NS is provided on the other end in the long side direction.
[0047] Details will be described later, but in this embodiment, the outer peripheral edge 13a of the sealing plate 13 and the opening edge 11a of the housing body 11 are laser welded, and the opening of the housing body 11 is blocked by the sealing plate 13.
[0048] [Structure of electrode body 40]
[0049] Figure 3 This is a three-dimensional view showing a portion of the electrode body 40 unfolded. For example... Figure 3 As shown, the electrode body 40 is a wound body formed by winding a long strip-shaped positive electrode 41 and a negative electrode 46 in a state where they are stacked with a strip-shaped separator 49 in between, and then compressing them into a flat shape. In this embodiment, the positive electrode 41 is an aluminum foil, and the negative electrode 46 is a copper foil.
[0050] The positive electrode 41 has a positive electrode coated portion 41a on both sides coated with positive electrode active material, and a positive electrode uncoated portion 41b on one side in the X-axis direction, which is not coated with positive electrode active material. Furthermore, the positive electrode 41 has a plurality of positive electrode tabs 42 that extend outward from the end on one side in the X-axis direction at intervals and have different lengths in the X-axis direction. The intervals between the plurality of positive electrode tabs 42 are set such that a positive electrode tab group 51 is formed at the center of the electrode body 40 in the height direction after winding. Furthermore, the length of each positive electrode tab 42 is set such that it becomes longer as it extends from one side in the Y-axis direction to the other after winding.
[0051] The negative electrode 46 has a negative electrode coated portion 46a on both sides coated with negative electrode active material, and a negative electrode uncoated portion 46b on the other side in the X-axis direction, which is not coated with negative electrode active material. Furthermore, the negative electrode 46 has a plurality of negative electrode tabs 47 that extend outward from the other side in the X-axis direction at intervals and have different lengths in the X-axis direction. The intervals between the plurality of negative electrode tabs 47 are set such that a negative electrode tab group 56 is formed at the center of the electrode body 40 in the height direction after winding. Furthermore, the length of each negative electrode tab 47 is set such that it becomes longer from one side in the Y-axis direction to the other after winding.
[0052] The separator 49 is configured to insulate the positive electrode coating portion 41a of the positive electrode 41 from the negative electrode coating portion 46a of the negative electrode 46. An insulating material that is permeable to ions (e.g., a porous insulating resin material) can be used in the separator 49.
[0053] The electrode body 40 extends a strip-shaped positive electrode tab group 51 from one end face in the winding axis direction (X-axis direction), and extends a strip-shaped negative electrode tab group 56 from the other end face. The positive electrode tab group 51 and the negative electrode tab group 56 are formed by layering the positive electrode tabs 42 and the negative electrode tabs 47 in a layered manner when the positive electrode member 41 and the negative electrode member 46, which have formed multiple positive electrode tabs 42 and negative electrode tabs 47, are wound.
[0054] In this embodiment, the positive electrode tab assembly 51 extends from one end of the electrode body 40, specifically from one side in the thickness direction (Y-axis direction) and the central side in the height direction (Z-axis direction) of the electrode body 40 when viewed from the winding axis direction (X-axis direction). Conversely, the negative electrode tab assembly 56 extends from the other end of the electrode body 40, specifically from one side in the thickness direction and the central side in the height direction when viewed from the winding axis direction. Furthermore, both the positive and negative electrode tab assemblies 51 and 56 are strip-shaped, with their long sides parallel to the X-axis direction of the electrode body 40 when viewed from the thickness direction. The tabs 42 and 47 constituting each tab assembly 51 and 56 increase in length in the X-axis direction as they extend from one side in the Y-axis direction towards the other. Thus, the tab assemblies 51 and 56 extend from both ends in the X-axis direction, which is orthogonal to the thickness direction (Y-axis direction) of the electrode body 40.
[0055] [Structure of the positive and negative electrodes]
[0056] In this embodiment, the secondary battery 1, as the positive electrode side structure, includes a positive electrode battery terminal PS composed of a positive electrode external terminal 25 and a positive electrode current collector terminal 27, a positive electrode insulating member 29, and a positive electrode pad 31. Furthermore, the secondary battery 1, as the negative electrode side structure, includes a negative electrode battery terminal NS composed of a negative electrode external terminal 26 and a negative electrode current collector terminal 28, a negative electrode insulating member 30, and a negative electrode pad 32.
[0057] Detailed descriptions are omitted, but in the secondary battery 1 of this embodiment, the positive external terminal 25, the positive current collector terminal 27, the negative external terminal 26, and the negative current collector terminal 28 are integrally formed into each battery terminal PS and NS by means of a seam-sealing process. Furthermore, in this embodiment, the positive external terminal 25 and the positive current collector terminal 27 constituting the positive battery terminal PS are both made of aluminum. On the other hand, regarding the negative battery terminal NS, the negative external terminal 26 is made of aluminum, and the negative current collector terminal 28 is made of copper.
[0058] In this embodiment, the positive external terminal 25 and the negative external terminal 26 are insulated from the sealing plate 13 by the positive electrode gasket 31 and the negative electrode gasket 32. Furthermore, the positive current collector terminal 27 and the negative current collector terminal 28 are insulated from the sealing plate 13 by the positive electrode insulating component 29 and the negative electrode insulating component 30. Each battery terminal PS, NS is kept airtight from the sealing plate 13 by the insulating components 29, 30 and the gaskets 31, 32. In this embodiment, the insulating components 29, 30 and the gaskets 31, 32 are made of PFA resin, but this is not a limitation. The material of the insulating components 29, 30 and the gaskets 31, 32 only needs to be insulating.
[0059] In this embodiment, each current collector terminal 27, 28 is formed by bending a plate-shaped component, and has a base 27a, 28a sewn into each of the external terminals 25, 26, and an electrode connection portion 27b, 28b continuous with the base 27a, 28a. That is, each current collector terminal 27, 28 is a single component having the electrode connection portion 27b, 28b. In addition, the term "single component" means that the current collector terminals 27, 28 are made of a coating material, and does not mean that the electrode connection portion 27b, 28b and other parts are formed as different components and then joined together by means of ultrasonic bonding or the like.
[0060] In this embodiment, each current collector terminal 27, 28 is generally rectangular when viewed from the Z-axis direction, and is arranged on the lower surface side of the sealing plate 13 with the bases 27a, 28a arranged horizontally. The electrode joint portions 27b, 28b of each current collector terminal 27, 28 are generally rectangular portions extending downwards in the Z-axis direction from the ends of the bases 27a, 28a, and are disposed between the electrode body 40 and the end sidewall of the housing body 11. Each electrode joint portion 27b, 28b has a first surface Ma, Mb (facing the end sidewall of the housing body 11) on the outer side in the X-axis direction, and a second surface M1, M2 on the opposite side of the first surface Ma, Mb. Furthermore, in this embodiment, the first surfaces Ma, Mb are "joint surfaces".
[0061] On the first surfaces Ma and Mb of the electrode joints 27b and 28b in each current collector terminal 27 and 28, the downstream sides of each tab assembly 51 and 56 in the extending direction are engaged. Each tab assembly 51 and 56 is folded back towards the electrode body 40 at the end of each electrode joint 27b and 28b in the Y-axis direction, in a state that follows the surface shape of each electrode joint 27b and 28b, and is housed between each electrode joint 27b and 28b and the end face of the electrode body 40 in the X-axis direction. Specifically, the positive electrode tab assembly 51 is folded back towards the electrode body 40 at its end 27b1 on one side of the electrode joint 27b in the X-axis direction, in a state that is upstream in the extending direction from the engagement portion A of the electrode joint 27b along the first surface Ma, and is housed between the second surface M1 of the electrode joint 27b and the end face of the electrode body 40. Furthermore, the negative electrode tab assembly 56, in a manner extending upstream of the electrode joint portion A along the first surface Mb, is folded back towards the electrode body 40 at its end 28b1 on one side of the electrode joint portion 28b in the X-axis direction, and is housed between the second surface M2 of the electrode joint portion 28b and the end face of the electrode body 40 (see also...). Figure 6 ).
[0062] Next, the manufacturing method of the secondary battery 1 will be described. The manufacturing method of the secondary battery 1 includes a bonding process and an alignment process. Hereinafter, with reference to... Figures 4-7 Each process is explained. Figure 4 This is a flowchart illustrating the manufacturing method of secondary battery 1. Figure 5 It is a top view used to illustrate the joining process. Figure 6 It is a top view used to illustrate the alignment process.
[0063] Figure 7 This is a partially enlarged view showing the state in which the electrode body 40 is assembled at the negative collector terminal 28.
[0064] [Jointing process]
[0065] The bonding process involves electrically connecting the pre-fabricated electrode body 40 to each battery terminal PS, NS that is mounted on the sealing plate 13. Furthermore, the fabrication of the electrode body 40 and the mounting of each battery terminal PS, NS to the sealing plate 13 can be performed appropriately using known methods. In the bonding process, the downstream side of each tab assembly 51, 56 in its extending direction is bonded to the first surface (bonding surface) Ma of the current collector terminals 27, 28 in each battery terminal PS, NS.
[0066] Specifically, in this embodiment, such as Figure 5As shown, with the current collector terminals 27 and 28 and the electrode body 40 arranged at different positions in the Y-axis direction, the first surfaces Ma and Mb of the electrode joints 27b and 28b are positioned opposite each other along the Y-axis direction to the portions of the tabs 51 and 56 corresponding to the electrode joints 27b and 28b located downstream in the extending direction. Specifically, the positive electrode tab 51 of the electrode body 40 is positioned opposite the first surface Ma of the electrode joint 27b. Similarly, the negative electrode tab 56 of the electrode body 40 is positioned opposite the first surface Mb of the electrode joint 28b.
[0067] Next, each electrode joint 27b, 28b is joined to each tab assembly 51, 56. Specifically, the first surfaces Ma, Mb of each electrode joint 27b, 28b are brought into contact with the surfaces opposite to the first surfaces Ma, Mb in the downstream extension direction of each tab assembly 51, 56. Next, an anvil (not shown) is pushed against the second surfaces M1, M2 of the electrode joints 27b, 28b, and a horn is pushed against the surface of each tab assembly 51, 56 opposite to the surface opposite to the first surfaces Ma, Mb along the X-axis direction and pressure is applied. Then, ultrasonic vibration in the vertical direction is applied by means of the horn. Thus, each electrode joint 27b, 28b is joined to each tab assembly 51, 56.
[0068] In this embodiment, the current collector terminals 27 and 28 and the electrode body 40 are arranged at different positions in the Y-axis direction. This allows for efficient use of the space between the positive current collector terminal 27 and the negative current collector terminal 28 of the final electrode body 40 to perform ultrasonic bonding using a horn and anvil.
[0069] [Alignment process]
[0070] The alignment process is performed after the joining process. In the alignment process, each battery terminal PS, NS is moved relative to the electrode body 40 along the Y-axis direction. While each tab assembly 51, 56 is folded back towards the electrode body 40 at the Y-axis end 27b1, 28b of the electrode joint 27b, 28b of each current collector terminal 27, 28, so that the electrode body 40 is aligned between each battery terminal PS, NS.
[0071] Specifically, in this embodiment, such as Figure 6As shown, the electrode body 40 is moved between the electrode junction 27b on the positive electrode side and the electrode junction 28b on the negative electrode side. At this time, each tab assembly 51, 56 is folded back at its ends 27b1, 28b1 so that the junction portion A with the electrode junctions 27b, 28b is aligned upstream along the first surfaces Ma, Mb and the second surfaces M1, M2, and then folded back once between the second surfaces M1, M2 and the end face of the electrode body 40. Thus, as... Figure 7 As shown, a portion of each tab assembly 51, 56 can be folded between the two end faces of the electrode body 40 and the electrode joints 27b, 28b, and the electrode body 40 can be aligned between the collector terminals 27, 28.
[0072] Thus, in this embodiment, the folding back at the ends 27b1 and 28b1 of the electrode joints 27b and 28b and the folding back between each electrode joint 27b and 28b and the end face of the electrode body 40 are performed twice in the alignment process.
[0073] Then, the electrode body 40, which is integrated with the sealing plate 13 and each battery terminal PS and NS, is housed in the housing body 11. A laser with a specified output is irradiated onto the boundary portion of the opening edge 11a of the housing body 11 and the outer peripheral edge 13a of the sealing plate 13 to weld the housing body 11 and the sealing plate 13, thereby closing the opening of the housing body 11.
[0074] Thus, in the manufacturing method of the secondary battery 1 according to this embodiment, when the electrode body 40 is installed on the current collector terminals 27 and 28 of each battery terminal PS and NS, the process of joining the components constituting the current collector terminals 27 and 28 to each other is not required, nor is the processing of joining the current collector terminals 27 and 28 to other components required. Therefore, the cost related to the battery terminals PS and NS is suppressed, and as a result, the manufacturing cost of the secondary battery 1 can be suppressed. Furthermore, since the size of the current collector terminals 27 and 28 is also suppressed, the shape of the battery casing 10 can be changed to increase the size of the battery casing 10, thereby increasing the length of the electrode body 40 in the X-axis direction and increasing the volume occupied by the electrode body 40 in the battery casing 10. Therefore, a secondary battery 1 with a larger battery capacity can be manufactured without changing the size of the battery casing 10 (specifically, its length in the X-axis direction).
[0075] [Modification 1 of the first embodiment]
[0076] Next, the secondary battery of Modification 1 of the first embodiment will be described. In this Modification 1, as... Figure 8As shown, in the secondary battery 1, the electrode joint 28b of the negative current collector terminal 28 is chamfered (chamfered portion 33). Specifically, a chamfered portion 33 is provided at the corner of the negative current collector terminal 28b where the negative electrode tab 56 contacts (in other words, at the corner of the end 28b1 on the Y-axis side). Although not shown, a chamfered portion 33 is also provided at the electrode joint 27b of the positive current collector terminal 27 opposite to the positive electrode tab 51. As a result, damage to the tab 56 (51) when bending it along the surface shape of the electrode joint 28b (27b) of the current collector terminal 28 (27) can be easily suppressed.
[0077] [Modification 2 of the first embodiment]
[0078] Next, the secondary battery 1 of Modification 2 of the first embodiment will be described. In this Modification 2, as Figure 9 As shown, the first surface Mb (joint surface) of the electrode joint 28b of the negative current collector terminal 28 is inclined such that the distance to the electrode body 40 decreases as it approaches one side in the Y-axis direction, and the inclined portion is formed as an inclined surface 34. Furthermore, in this modified example 2, the first surface Mb is entirely an inclined surface 34. Although not shown, the first surface Ma (joint surface) of the electrode joint 27b of the positive current collector terminal 27 is also inclined such that the distance to the electrode body 40 decreases as it approaches one side in the Y-axis direction, and the inclined portion is formed as an inclined surface 34 (in this modified example 2, the first surface Ma is entirely an inclined surface 34). Furthermore, during the alignment process, the tab assembly 56 (51) is folded back towards the electrode body 40 along the outer periphery of one side in the X-axis direction of the electrode joint 28b (27b). Thus, when each tab assembly is folded back towards the electrode body, it is folded back along the inclined joint surface (inclined surface 34). Therefore, the flexibility of the tab assembly 56 (51) is improved, and the tab assemblies 51 and 56 can be housed along the inclined surface 34 of the electrode joint 28b (27b). As a result, the secondary battery 1 can increase the size of the electrode body 40 in the X-axis direction and thus increase the battery capacity. In addition, in this modified example 2, the first surfaces Ma and Mb of each electrode joint 27b and 28b are all inclined surfaces 34, but it is also possible that only the first surfaces Ma and Mb are inclined on the side of the joint A that is closer to the Y-axis direction.
[0079] [Modification 3 of the first embodiment]
[0080] Next, the secondary battery 1 of the modified example 3 of the first embodiment will be described. In this modified example 3, as Figure 10As shown, during the alignment process, when the negative electrode tab assembly 56 is folded back between the second surface M2 of the electrode joint 28b and the end face of the electrode body 40, a clamp J is used to press the negative electrode tab assembly 56. The clamp J is, for example, a rod-shaped component. In addition, the clamp is used on the positive electrode side in the same way. Since the tab assembly 56 (51) is pressed in the Y-axis direction by means of the clamp J, the tab assembly 56 (51) can be efficiently and well housed between the electrode joint 28b (27b) and the end face of the electrode body 40.
[0081] [Modification 4 of the first embodiment]
[0082] Next, the secondary battery 1 of Modification 4 of the first embodiment will be described. In this Modification 4, as Figure 11 As shown, the electrode joint 28b (27b) of the collector terminal 28 (27) has a first portion 28bA (27bA) of a predetermined thickness in the Z-axis direction, and a second portion 28bB (28bB) whose outer surface is recessed from the first portion 28bA (27bA). That is, the second portion 27bB (28bB) is thinner than the first portion 28bA (27bA). In the electrode joint 28b (27b) of the collector terminal 28 (27), the outer surface of the second portion 28bB (27bB) can be used as the first surface (joint surface) Mb (Ma) with the tab assembly 56 (51). As a result, when the tab assembly 56 (51) is joined to the second portion 28bB (27bB) of the electrode junction 28b (27b) of the current collector terminal 28 (27), the size in the X-axis direction can be reduced according to the amount of plate thickness reduction, and the secondary battery 1 can be compactly constructed. In addition, by reducing the plate thickness only at the portion where the tab assembly 56 (51) is joined (the second portion 27bB, 28bB), the deterioration of the on-resistance in the electrode junction 28b (27b) can be minimized.
[0083] [Modification 5 of the first embodiment]
[0084] Next, the secondary battery 1 of Modification 5 of the first embodiment will be described. In the secondary battery 1 of the first embodiment, the electrode body 40 is aligned between the current collector terminals 27 and 28. For example, due to interference caused by vehicle vibration, the electrode body 40 may shift in position in the Y-axis direction, or the electrode body 40 may rotate about an axis along the X-axis direction. Therefore, in this Modification 5, as... Figure 12 As shown, the current collector terminal 28 (27) and the electrode body 40 are covered with a box-shaped insulating film F with an opening at the top, and the upper end of the insulating film F is fused to the lower surface of the sealing plate 13. As a result, the insulating film F can be used to prevent the electrode body 40 from shifting in position in the Y-axis direction and from rotating about the aforementioned axis.
[0085] [Second Implementation]
[0086] Next, the second embodiment will be described. Furthermore, the following mainly describes the differences from the first embodiment; points similar to the first embodiment are omitted. In the second embodiment, as... Figure 13 As shown, two electrode bodies 40, 40 are joined to current collector terminals 27, 28. In this case, during the joining process, the length of the tab assemblies 51, 56 of the electrode body 40 located closer to the electrode joints 27b, 28b in the Z-axis direction is set to be shorter than that of the other electrode body 40. By doing so, the front ends of the tab assemblies 51, 56 of the two electrode bodies 40, 40 at the joining part A are aligned. In this state, each tab assembly 51, 56 is joined to the first surface (joining surface) Ma, Mb of each electrode joint 27b, 28b, and while folding each tab assembly 51, 56 back appropriately, the electrode body 40 is aligned between the current collector terminals 27, 28, thereby assembling the two electrode bodies 40, 40 onto the current collector terminals 27, 28.
[0087] [Modifications of the Second Embodiment]
[0088] Next, a variation of the second embodiment will be described. In this variation, as... Figure 14 As shown, the lengths of the tab assemblies 51 and 56 of the two electrode bodies 40, 40 are set to be the same. If this is the case, during the joining process, when viewed in the Z-axis direction, one end 51a, 56a of the tab assemblies 51 and 56 of the electrode body 40, located closer to the electrode joint portions 27b, 28b, protrudes from the joint portion A. However, in this case, by appropriately cutting off the protruding portions, i.e., one end 51a, 56a, the front ends of the tab assemblies 51 and 56 of the two electrode bodies 40, 40 can be easily aligned.
[0089] [Third Implementation Method]
[0090] Next, the third embodiment will be described. Furthermore, the following mainly describes the differences from the first and second embodiments; points similar to the first and second embodiments are omitted. In the third embodiment, as... Figure 15 As shown, four electrode bodies 40 are engaged with current collector terminals 27 and 28. In this case, during the engagement process, two electrode bodies 40 are respectively positioned on both sides of the current collector terminals 27 and 28 in the Y-axis direction, and during the alignment process, the four electrode bodies 40 are moved relative to each other. That is, when viewed in the Z-axis direction, two electrode bodies 40 are inserted between the current collector terminals 27 and 28 from both sides. By doing so, the four electrode bodies 40 can be assembled on the current collector terminals 27 and 28.
[0091] [Other implementation methods]
[0092] [1] In the above embodiment, the configuration in which the tabs 51 and 56 are folded back once between the second surfaces M1 and M2 of the electrode joints 27b and 28b and the end face of the electrode body 40 has been described, but the configuration is not limited to this configuration. It is also possible that the tabs 51 and 56 are folded back more than twice between the second surfaces M1 and M2 of the electrode joints 27b and 28b and the end face of the electrode body 40.
[0093] [2] In the above embodiment, the shape of each tab group 51, 56 extending from one side of the electrode body 40 in the thickness direction (Y-axis direction) when viewed from the winding axis direction (X-axis direction) has been described, but it is not limited to this shape. For example, each tab group 51, 56 may also extend from the central part of the electrode body 40 in the thickness direction (Y-axis direction) when viewed from the winding axis direction (X-axis direction).
[0094] [3] In the above embodiments, the secondary battery 1 is described as having one, two, or four electrode bodies 40, but is not limited to such a form. The number of electrode bodies can also be three, five or more, or four or more. In this case, as long as multiple tab groups are overlapped and joined to one electrode joint corresponding to the number of electrode bodies, the number of electrode bodies can be increased while suppressing the increase in the number of parts.
[0095] [4] In the above embodiment, the configuration in which the positive electrode tab group 51 and the negative electrode tab group 56 of each electrode body 40 are positioned in the same position in the Z-axis direction has been described, but the configuration is not limited to this. The positive electrode tab group and the negative electrode tab group of each electrode body may also be located above or below the center in the Z-axis direction. The positive electrode tab group and the negative electrode tab group of each electrode body may also be located at different positions in the Z-axis direction.
[0096] [5] In the above embodiment, the electrode body 40 is described as a wound body, but it is not limited to this form. The electrode body 40 is not particularly limited as long as it has a positive electrode tab group and a negative electrode tab group, and various structures used in general sealed secondary batteries can be adopted.
[0097] Furthermore, the structures disclosed in the above embodiments (including other embodiments, the same below) can be combined with the structures disclosed in other embodiments as long as there is no contradiction. In addition, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope of the purpose of the present invention.
[0098] Explanation of reference numerals in the attached figures
[0099] 1: Secondary battery
[0100] 11: Main body of the shell (box)
[0101] 13: Sealing plate (lid)
[0102] 27, 28: Collector terminals
[0103] 27b, 28b: Electrode junction
[0104] 27b1, 28b1: Ends
[0105] 33: Chamfered section
[0106] 34: Inclined surface
[0107] 40: Electrode body
[0108] 41: Positive electrode
[0109] 42: Positive electrode tab
[0110] 46: Negative electrode component
[0111] 47: Negative electrode tab
[0112] 51: Positive electrode tab assembly
[0113] 56: Negative electrode tab assembly
[0114] Ma, Mb: Joint surface
[0115] PS: Positive battery terminal (battery terminal)
[0116] NS: Negative battery terminal (battery terminal)
Claims
1. A method for manufacturing a secondary battery, comprising a casing with an opening, a cover mounted on the opening of the casing, a flat electrode body formed by stacking a positive electrode and a negative electrode separated by a separator, and a positive electrode terminal and a negative electrode terminal respectively mounted on the cover, characterized in that, The aforementioned electrode body extends from one end face in a second direction orthogonal to the thickness direction of the aforementioned electrode body, forming a strip-shaped positive electrode tab assembly by stacking the tabs of the aforementioned positive electrode component; and extends from the other end face in the aforementioned second direction, forming a strip-shaped negative electrode tab assembly by stacking the tabs of the aforementioned negative electrode component. The aforementioned positive electrode battery terminal and the aforementioned negative electrode battery terminal have current collector terminals, and the current collector terminals include plate-shaped electrode joint portions disposed between each end face of the aforementioned electrode body and the aforementioned housing in the aforementioned second direction along the end face of the electrode body. The surface of the aforementioned electrode joint that faces the aforementioned housing is the joint surface; The aforementioned method for manufacturing secondary batteries includes: In the joining process, the downstream side of the aforementioned positive electrode tab assembly is joined to the aforementioned joining surface of the aforementioned current collector terminal in the aforementioned positive electrode battery terminal, and the downstream side of the aforementioned negative electrode tab assembly is joined to the aforementioned joining surface of the aforementioned current collector terminal in the aforementioned negative electrode battery terminal. as well as In the alignment process, after the aforementioned joining process, the aforementioned positive electrode terminal and the aforementioned negative electrode terminal are moved relative to the aforementioned electrode body along the aforementioned first direction. While the aforementioned positive electrode tab group and the aforementioned negative electrode tab group are folded back towards the aforementioned electrode body at the end of the aforementioned electrode joint in the aforementioned first direction along the surface shape of the aforementioned electrode joint of each of the aforementioned current collector terminals, the aforementioned positive electrode tab group and the aforementioned negative electrode tab group are aligned between the aforementioned positive electrode terminal and the aforementioned negative electrode terminal.
2. The method for manufacturing a secondary battery as described in claim 1, characterized in that, In the aforementioned alignment process, at least a portion of the aforementioned positive electrode tab assembly and the aforementioned negative electrode tab assembly are arranged to be folded back once or multiple times between each of the aforementioned electrode joints and the end face of the aforementioned electrode body in the aforementioned second direction for storage.
3. The method for manufacturing a secondary battery as described in claim 1, characterized in that, The aforementioned electrode joint was chamfered.
4. The method for manufacturing a secondary battery according to any one of claims 1 to 3, characterized in that, The aforementioned engagement surface of the aforementioned electrode engagement portion is inclined such that the distance to the aforementioned electrode body decreases as it moves toward one side of the aforementioned first direction.
5. A secondary battery comprising a housing with an opening, a cover mounted on the opening of the housing, a flat electrode body formed by stacking a positive electrode and a negative electrode separated by a separator, and a positive battery terminal and a negative battery terminal respectively mounted on the cover, characterized in that, The aforementioned electrode body Contained inside the aforementioned box, A strip-shaped positive electrode tab assembly formed by stacking the tabs of the aforementioned positive electrode extends from one end face in a second direction orthogonal to the thickness direction of the aforementioned electrode body, i.e., the first direction; and a strip-shaped negative electrode tab assembly formed by stacking the tabs of the aforementioned negative electrode extends from the other end face. The aforementioned positive electrode battery terminal and the aforementioned negative electrode battery terminal have current collector terminals including electrode joints; The aforementioned electrode joint is a plate-shaped component disposed between each end face of the aforementioned electrode body and the aforementioned housing in the aforementioned second direction along the end face of the electrode body, and the surface opposite to the aforementioned housing is the joint surface. When the aforementioned positive electrode tab group and the aforementioned negative electrode tab group are engaged with the aforementioned joint surfaces of the aforementioned current collector terminals of the aforementioned positive electrode terminal and the aforementioned negative electrode terminal on the downstream side of the extending direction, they are folded back towards the aforementioned electrode body at the end of the aforementioned electrode joint in the aforementioned first direction along the surface shape of the aforementioned electrode joint portion of the aforementioned current collector terminal, and are housed between the aforementioned electrode joint portion and the end face of the aforementioned electrode body in the aforementioned second direction.
Citation Information
Patent Citations
Secondary battery and method for manufacturing same
WO2021060009A1