Secondary battery
By designing a secondary battery structure in which the tab assembly and the bent portion of the battery terminal do not overlap, the problems of tab assembly damage and high processing difficulty were solved, thereby increasing battery capacity and simplifying processing.
Patent Information
- Application Number
- CN202510164870.0
- 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
In existing secondary batteries, the electrode tabs are easily damaged when they overlap with the battery terminals at the connection points and bends, and the manufacturing process is difficult.
Design a secondary battery structure in which the tabs of the electrode body extend from the end face of the electrode body, the bent part of the battery terminal does not overlap with the tabs, and forms a receiving space when bent, and the connection between the tabs and the electrode junction is achieved by ultrasonic bonding.
It reduces damage to the tab assembly, improves processing ease, and increases battery capacity without changing the battery casing size.
Smart Images
Figure CN120854853A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to secondary batteries. Background Technology
[0002] Conventional secondary batteries used in electric vehicles, such as electric cars, which use a motor as a drive source, include electrode bodies, a casing housing the electrode bodies, and battery terminals mounted on the casing and electrically connected to the electrode bodies. For example, the battery disclosed in Patent Document 1 exists as such a secondary battery.
[0003] Patent Document 1 describes a battery that houses an electrode body within its casing, with a positive and a negative terminal connected to the electrode body as battery terminals. The positive and negative terminals each have a guide portion that abuts against the end face of the electrode body, and a connection portion that extends flexibly relative to the guide portion via a bending portion to connect with a tab assembly extending from the electrode body. Specifically, the positive and negative terminals have recesses in the bending portion, improving bending workability and bending precision.
[0004] Patent document 1: International Publication No. 2019 / 140779.
[0005] However, in the battery described in Patent Document 1, the electrode tabs of the electrode body are bent while overlapping the connection and bending portion with the battery terminal, which may cause damage to the tabs. Furthermore, since the electrode tabs need to be bent while overlapping the bending portion with the battery terminal, there is room for improvement in processing ease. Summary of the Invention
[0006] The present invention was made in view of the above-mentioned actual situation, and its purpose is to provide a secondary battery that can suppress damage to the electrode tab assembly of the electrode body and improve the ease of processing.
[0007] To achieve the above objectives, the secondary battery of the present invention is characterized by the following structure:
[0008] A secondary battery comprises a casing, a cover, electrode bodies, and battery terminals. The casing has an opening, the cover is installed in the opening of the casing, the electrode bodies are formed by stacking positive and negative electrode materials with a separator in between, the electrode bodies are flat, and the battery terminals are installed in the cover.
[0009] The aforementioned electrode body comprises an electrode lug assembly formed by stacking the aforementioned positive electrode material and the aforementioned negative electrode material, and is housed within the aforementioned housing.
[0010] The aforementioned tab assembly extends from the end face of the aforementioned electrode body in a second direction orthogonal to the thickness direction, i.e., the first direction.
[0011] The aforementioned battery terminal has a guide portion disposed on an end face along the aforementioned second direction of the aforementioned electrode body, a plate-shaped electrode engagement portion extending from the aforementioned guide portion, and a curved portion between the aforementioned guide portion and the aforementioned electrode engagement portion.
[0012] The aforementioned electrode joint has a mating surface at a position corresponding to the aforementioned tab assembly on at least one of its surfaces.
[0013] The aforementioned curved portion, when viewed along the aforementioned second direction, has a different upward position from the aforementioned tab assembly of the aforementioned electrode body on a third direction orthogonal to the aforementioned first direction.
[0014] With the aforementioned tab assembly and the aforementioned electrode joint surface engaged, the aforementioned bending portion is bent so that the aforementioned electrode joint and the aforementioned tab assembly are facing the aforementioned end face of the aforementioned electrode body in the aforementioned second direction.
[0015] Based on the aforementioned structural features, the bent portion of the battery terminal and the tab assembly do not overlap, thus reducing the bending load acting on the tab assembly when bending the electrode joint. This helps to suppress damage to the tab assembly. Furthermore, because the bent portion of the battery terminal and the tab assembly do not overlap, it is easier to bend the electrode joint at the bent portion during secondary battery manufacturing, improving processability.
[0016] A further structural feature of the secondary battery of the present invention is that,
[0017] There is a receiving space between the aforementioned end face of the aforementioned electrode body in the aforementioned second direction and the aforementioned joint surface of the aforementioned electrode joint, and the aforementioned tab assembly is housed in the aforementioned receiving space.
[0018] Based on the above-mentioned structural features, compared with the case without a storage space, the size of the electrode body in the second direction can be increased to increase the battery capacity without changing the size of the casing.
[0019] A further structural feature of the secondary battery of the present invention is that,
[0020] It has multiple of the aforementioned electrode bodies,
[0021] Each of the aforementioned electrode bodies has its respective tab assembly engaged with the aforementioned engagement surface of the aforementioned electrode joint.
[0022] Based on the above-mentioned structural features, multiple electrode bodies are electrically connected to the electrode junction, thus increasing the capacity of the secondary battery.
[0023] A further structural feature of the secondary battery of the present invention is that,
[0024] The overlapping portion of the aforementioned electrode bodies having overlapping tabs in a direction orthogonal to the aforementioned engagement surface of the aforementioned electrode engagement portion.
[0025] The aforementioned overlapping portion engages with the aforementioned engagement surface of the aforementioned electrode engagement portion.
[0026] Based on the aforementioned structural features, the engagement of the tabs of each electrode body with the electrode joint can be performed, for example, by a single ultrasonic engagement, with the overlapping portion and the engagement surface of the electrode joint facing each other. Therefore, even if the number of electrodes increases, the increase in the time required for engagement of the tabs of each electrode body with the electrode joint can be suppressed. Consequently, the capacity of the secondary battery can be increased while suppressing the increase in the assembly time required for the secondary battery.
[0027] Invention Effects
[0028] As described above, the secondary battery according to the present invention can suppress damage to the electrode tab assembly of the electrode body and also improve the ease of processing. Attached Figure Description
[0029] Figure 1 This is an exploded perspective view of the secondary battery according to the first embodiment.
[0030] Figure 2 This is a cross-sectional view showing the general structure of a secondary battery.
[0031] Figure 3 It is a three-dimensional diagram showing a partially unfolded electrode.
[0032] Figure 4 It is a three-dimensional diagram used to illustrate the positional relationship between the electrode body and the negative current collector terminal before ultrasonic bonding.
[0033] Figure 5 yes Figure 2 VV-direction sectional view.
[0034] Figure 6 yes Figure 2 Sectional view along line VI-VI.
[0035] Figure 7 This is a partial top sectional view of a comparative example secondary battery.
[0036] Figure 8 This is a partial perspective view of the secondary battery according to the second embodiment.
[0037] Figure 9 This is a cross-sectional view showing the schematic structure of the secondary battery according to the second embodiment.
[0038] Figure 10 This is a partial top sectional view of the electrode body and current collector terminals of the secondary battery according to the second embodiment.
[0039] Figure 11This is a partial top sectional view of the electrode body and current collector terminals of a secondary battery according to other embodiments.
[0040] Figure 12 This is a partial top sectional view of the electrode body and current collector terminals of a secondary battery according to other embodiments.
[0041] Figure 13 This is a partial perspective view of the secondary battery of Modified Example 1 of the second embodiment.
[0042] Figure 14 This is a partial top sectional view of the secondary battery of Modified Example 1 of the second embodiment.
[0043] Figure 15 This is a partial top sectional view of a secondary battery according to other embodiments.
[0044] Figure 16 This is a partial top sectional view of the secondary battery according to the third embodiment. Detailed Implementation
[0045] Hereinafter, a secondary battery according to an 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. For clarity, the description and drawings will be appropriately simplified below.
[0046] [Summary of Secondary Battery 1]
[0047] Reference Figure 1 and Figure 2 The general outline of the secondary battery 1 in this embodiment will be described. Furthermore, 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 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, while 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."
[0048] like Figure 1 and Figure 2As 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 in which an electrode body 40 and current collector terminals 27 and 28 are housed inside the casing body 11, and the opening of the casing body 11 is sealed by the sealing plate 13, and electrolyte is injected into the interior of the casing body 11.
[0049] [Structure of battery casing 10]
[0050] like Figure 1 and Figure 2 As shown, the battery casing 10 of this embodiment consists of a generally rectangular shell body 11 with an opening at the top and a sealing plate 13 that closes the opening of the shell body 11. In this embodiment, both the shell 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 the materials for the shell body 11 and the sealing plate 13. In this embodiment, the shell body 11 is equivalent to a "box", and the sealing plate 13 is equivalent to a "cover".
[0051] In this embodiment, the sealing plate 13 has a shape corresponding to the shape of the opening of the shell body 11, and is configured to close the opening of the shell body 11. Specifically, the sealing plate 13 in this embodiment is composed of a flat plate component that is approximately rectangular in shape when viewed in the Z-axis direction. A positive battery terminal PS is provided at one end of the sealing plate 13 in the long side direction (X-axis direction), and a negative battery terminal NS is provided at the other end in the long side direction.
[0052] Details will be explained later, but in this embodiment, the outer peripheral edge 13a of the sealing plate 13 and the opening edge 11a of the shell body 11 are laser welded, and the opening of the shell body 11 is blocked by the sealing plate 13.
[0053] [Structure of electrode body 40]
[0054] 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 composed of a flat, wound body, which is formed by winding and compressing long strips of positive electrode material 41 and negative electrode material 46 in a stacked state with a strip-shaped separator 49 in between. In this embodiment, the positive electrode material 41 is aluminum foil, and the negative electrode material 46 is copper foil.
[0055] The positive electrode material 41 has a positive electrode coated portion 41a coated with positive electrode active material on both sides, and a positive electrode uncoated portion 41b with no positive electrode active material coated at one end in the X-axis direction. Furthermore, the positive electrode material 41 has a plurality of positive electrode tabs 42 extending outward from one end in the X-axis direction at intervals. The spacing between the plurality of positive electrode tabs 42 is set such that a positive electrode tab assembly 51 is formed at the center of the electrode body 40 in the height direction after winding.
[0056] The negative electrode material 46 has negative electrode coated portions 46a coated with negative electrode active material on both sides, and a negative electrode uncoated portion 46b uncoated with negative electrode active material at the other end in the X-axis direction. Furthermore, the negative electrode material 46 has a plurality of negative electrode tabs 47 extending outward from the other end in the X-axis direction at intervals. The spacing between the plurality of negative electrode tabs 47 is configured such that a negative electrode tab group 56 is formed at the center of the electrode body 40 in the height direction after winding.
[0057] The separator 49 is configured to insulate the positive electrode coating portion 41a of the positive electrode material 41 and the negative electrode coating portion 46a of the negative electrode material 46. The separator 49 can be made of an insulating material that is permeable to ions (e.g., a porous insulating resin material).
[0058] The electrode body 40 has a positive electrode tab group 51 extending from one end face in the winding axis (X-axis direction) and a negative electrode tab group 56 extending 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 negative electrode tabs 47 when the positive electrode material 41 and the negative electrode material 46, which have multiple positive electrode tabs 42 and negative electrode tabs 47, are wound together.
[0059] In this embodiment, the positive electrode tab assembly 51 extends from one side of the electrode body 40 along the winding axis (X-axis direction) and the central side of the electrode body 40 along the thickness direction (Y-axis direction) and the height direction (Z-axis direction) when viewed from one end face of the electrode body 40. Conversely, the negative electrode tab assembly 56 extends from one side of the electrode body 40 along the winding axis and the central side of the electrode body 40 along the thickness direction when viewed from the other end face of the electrode body 40. Furthermore, both the positive electrode tab assembly 51 and the negative electrode tab assembly 56 are rectangular in shape, with their long sides parallel to the height direction of the electrode body 40 when viewed from the thickness direction of the electrode body 40. Thus, the tab assemblies 51 and 56 extend from both end faces in the X-axis direction, which is orthogonal to the thickness direction (Y-axis direction) of the electrode body 40.
[0060] [Structure of the positive and negative electrodes]
[0061] like Figure 1 and Figure 2As shown, in this embodiment, the secondary battery 1, as the positive electrode side, 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 gasket 31. Furthermore, the secondary battery 1, as the negative electrode side, 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 gasket 32.
[0062] Although detailed descriptions are omitted, in the secondary battery 1 of this embodiment, the positive external terminal 25 and the positive current collector terminal 27, and the negative external terminal 26 and the negative current collector terminal 28, are respectively integrated by fastening to form each battery terminal PS and NS. Furthermore, in this embodiment, both the positive external terminal 25 and the positive current collector terminal 27 constituting the positive battery terminal PS are 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.
[0063] In this embodiment, the positive external terminal 25 and the negative external terminal 26 are insulated from the sealing plate 13 by positive gasket 31 and negative gasket 32, respectively. Furthermore, the positive current collector terminal 27 and the negative current collector terminal 28 are insulated from the sealing plate 13 by positive insulating component 29 and negative insulating component 30, respectively. Each battery terminal PS, NS is airtight with the sealing plate 13 by insulating components 29, 30 and gaskets 31, 32. In this embodiment, the insulating components 29, 30 and gaskets 31, 32 are made of PFA resin, but this is not a limitation. The material of the insulating components 29, 30 and gaskets 31, 32 only needs to be insulating.
[0064] In this embodiment, each current collector terminal 27, 28 is formed by bending a plate-shaped component and has a base 27a, 28a that is fastened to each external terminal 25, 26, a guide portion 27b, 28b continuous with the base 27a, 28a, and an electrode connection portion 27c, 28c continuous with the guide portion 27b, 28b. The electrode connection portions 27c, 28c have a first portion 27c1, 28c1 extending along the X-axis direction and a second portion 27c2, 28c2 extending from the first portion 27c1, 28c1 along the Z-axis direction. A bent portion 27d, 28d is provided between the guide portion 27b, 28b and the first portion 27c1, 28c1.
[0065] In this embodiment, the bases 27a and 28a of each current collector terminal 27 and 28, which are approximately rectangular in shape when viewed in the Z-axis direction, are arranged horizontally on the lower surface of the sealing plate 13. The guide portions 27b and 28b of each current collector terminal 27 and 28 are approximately rectangular in shape when viewed in the X-axis direction, extending from the ends of the bases 27a and 28a downward in the Z-axis direction to near the center of the electrode body 40 in the Z-axis direction, and are disposed between the end sidewall of the electrode body 40 and the shell body 11.
[0066] The electrode junctions 27c and 28c of each current collector terminal 27 and 28 are formed at positions that allow them to engage with the tabs 51 and 56 of the electrode body 40. Specifically, each electrode junction 27c and 28c (first portions 27c1 and 28c1 and second portions 27c2 and 28c2) before the electrode body 40 is a roughly rectangular portion when viewed along the Y-axis direction, extending from one edge of the guide portions 27b and 28b along the X-axis direction. The second portions 27c2 and 28c2 are located below the lower end of the guide portions 27b and 28b. Furthermore, the boundary between the first portions 27c1 and 28c1 and the guide portions 27b and 28b is a curved portion 27d and 28d. The second portions 27c2 and 28c2 of each electrode junction 27c and 28c have inner surfaces in the Y-axis direction (surfaces facing the center of the electrode body 40 when viewed in the X-axis direction) that are mating surfaces Ma and Mb, respectively. Each tab assembly 51 and 56 is mated to these mating surfaces Ma and Mb. Details will be explained later. With the corresponding tab assemblies 51 and 56 of each current collector terminal 27 and 28 mated to mating surfaces Ma and Mb, the electrode junctions 27c and 28c are bent at bending portions 27d and 28d such that the mating portion (junction) A between each electrode junction 27c and 28c and each tab assembly 51 and 56 faces the end face of the electrode body 40 in the X-axis direction (see reference). Figure 2 and Figure 6 ).
[0067] Here, in this embodiment, with the electrode joints 27c and 28c bent at the bends 27d and 28d, a receiving space S (refer to) is formed between the joint surfaces Ma and Mb of the electrode joints 27c and 28c (specifically, the second portions 27c2 and 28c2) and the end face of the electrode body 40 in the X-axis direction. Figure 2 , Figure 6 Furthermore, in this embodiment, each tab assembly 51, 56 is accommodated within the accommodating space S. Therefore, compared to the case where the accommodating space S is not formed, the dimension of the electrode body 40 in the X-axis direction can be lengthened, and the volume occupied by the electrode body 40 in the battery case 10 can be increased. Therefore, the battery capacity can be increased without changing the dimensions of the battery case 10 (specifically, the length in the X-axis direction).
[0068] Next, refer to Figures 4-6 The method of mounting the electrode body 40 to each collector terminal 27, 28 is described. Figure 4 This is a partial perspective view illustrating the positional relationship between the electrode body 40 and the negative current collector terminal 28 before ultrasonic bonding. Figure 5 and Figure 6 This is a top sectional view illustrating the positional relationship between the electrode body 40 and the negative current collector terminal 28 in the state after ultrasonic bonding when the electrode joints 27c and 28c are bent.
[0069] like Figure 4 As shown, the electrode body 40 is positioned on the negative current collector terminal 28 mounted on the sealing plate 13 such that the electrode joint 28c and the corresponding tab group 56 face each other in the Y-axis direction. That is, the negative current collector terminal 28 is configured such that the mating surfaces Mb of the negative tab group 56 of the electrode body 40 and the electrode joint 28c (second part 28c2) face each other in the Y-axis direction. Furthermore, although not shown in the figure, the positive current collector terminal 27 is positioned such that the mating surfaces Ma of the positive tab group 51 of the electrode body 40 and the electrode joint 27c (second part 27c2) face each other in the Y-axis direction.
[0070] Next, each electrode joint 27c, 28c is joined to each tab assembly 51, 56. Specifically, the mating surfaces Ma, Mb of each electrode joint 27c, 28c (second parts 27c2, 28c2) are brought into contact with the surfaces of each tab assembly 51, 56 opposite to the mating surfaces Ma, Mb. Then, the anvil (not shown) is pushed against the surface of the electrode joint 27c, 28c opposite to the mating surfaces Ma, Mb, and the horn is pressed and pressured along the Y-axis towards the surface of each tab assembly 51, 56 opposite to the surfaces facing the mating surfaces Ma, Mb. Then, ultrasonic vibration in the vertical direction is applied using the horn. Thus, each electrode joint 27c, 28c and each tab assembly 51, 56 are joined.
[0071] Next, with the electrode joints 27c and 28c of each current collector terminal 27 and 28 engaged with each tab assembly 51 and 56, the electrode joints 27c and 28c are bent at the bending portions 27d and 28d, so that the first portions 27c1 and 28c1 abut against the guide portions 27b and 28b, and each engagement portion A faces the end face of the electrode body 40 in the X-axis direction (see reference). Figure 5 and Figure 6 ).
[0072] Figure 7 This is a partial top sectional view of a comparative example secondary battery. For example... Figure 7As shown in the comparative example, in the configuration where the electrode joint 78c and the corresponding negative electrode tab 56 face each other in the X-axis direction, and the negative electrode tab 56 is folded to cover the electrode joint 78c from the outside, when bending the electrode joint 78c, the negative electrode tab 56 is bent while overlapping with the electrode joint 78c. Therefore, the bending area increases with the thickness of the guide portion 78b and the electrode joint 78c, resulting in a larger bending load on the negative electrode tab 56 and making it more susceptible to damage. Furthermore, if the electrode joint 78c and the negative electrode tab 56 overlap, the electrode joint 78c is difficult to bend, so sometimes a process is needed to make it easier to bend (e.g., a process to thin the thickness of the bent portion).
[0073] In contrast, in the secondary battery 1 of this embodiment, the bent portion 27d and the negative electrode tab assembly 56 do not overlap. Therefore, when bending the electrode joint portion 28c, the bending area is not increased due to the thickness of the guide portion 28b and the electrode joint portion 28c as in the comparative example, and it is easy to bend. Thus, the bending load acting on the negative electrode tab assembly 56 can be reduced, damage to the negative electrode tab assembly 56 can be suppressed, and bending accuracy is also improved. In other words, the secondary battery 1 according to this embodiment can suppress damage to the tab assemblies 51 and 56 during manufacturing, and also improves processing ease.
[0074] [Second Implementation]
[0075] Next, the secondary battery of the second embodiment will be described. Furthermore, the following description mainly focuses on structures different from those of the first embodiment, omitting structures identical to those of the first embodiment. For example... Figures 8-10 As shown, the secondary battery of the second embodiment has two electrode bodies 40, 40 inside the battery casing 10. The negative electrode tabs 56, 56 of each of the two electrode bodies 40, 40 are engaged with the electrode junction 28c in a state overlapping the engagement surface Mb side of the second portion 28c2 of the electrode junction 28c. Figure 8 and Figure 10 Although not shown in the figure, the positive electrode tabs 51, 51 are only opposite in position to the electrode joint 28c in the Y-axis direction, and are joined on the Ma side of the joint surface of the second part 27c2 of the electrode joint 27c. That is, in the secondary battery of the second embodiment, there is an overlapping portion D of the positive electrode tabs 51, 51 of all electrode bodies 40, 40 in a direction orthogonal to the second parts 27c2, 28c2 of the electrode joints 27c, 28c, and an overlapping portion D of the negative electrode tabs 56, 56, and each tab group 51, 56 is joined to the second part 27c2, 28c2 of the electrode joints 27c, 28c at the overlapping portion D.
[0076] like Figure 10As shown, the electrode junction 28c is positioned near the center of the two electrode bodies 40, 40 and close to one side of the electrode body 40 in the Y-axis direction. After the two negative electrode tabs 56, 56 are ultrasonically joined with the electrode junction 28c at the overlapping portion D of the junction A, they are bent and accommodated in the receiving space S with the second portion 28c2 of the electrode junction 28c located on the outside (in other words, with the junction A facing the end face of one of the electrode bodies 40, 40). The same applies to the positive electrode side.
[0077] Furthermore, the positional relationship between the electrode joints 27c, 28c and the two electrode bodies 40, 40, and the position of the tabs 51, 56 of the electrode bodies 40 in the Y-axis direction are not particularly limited. For example, as Figure 11 As shown, alternatively, the electrode junction 28c can be positioned in the Y-axis direction on the center line C of the two electrode bodies 40, 40. The negative electrode tab 56 of one electrode body 40 is formed close to the center line C, while the negative electrode tab 56 of the other electrode body 40 is formed away from the center line C. In this case, the protruding lengths of the two negative electrode tabs 56, 56 in the X-axis direction differ, but there is no problem as long as the two negative electrode tabs 56, 56 have an overlapping portion D, and this overlapping portion D and the second portion 28c2 are joined at the junction A above a predetermined area. Furthermore, as... Figure 12 As shown, it is also conceivable that the negative electrode tab group 56 of one of the electrode bodies 40 protrudes from the electrode joint 28c in the X-axis direction, but in this case, the protruding part 56a of the negative electrode tab group 56 can be appropriately cut off before bending.
[0078] In the secondary battery of the second embodiment, multiple electrode bodies 40, 40 are electrically connected to electrode joints 27c, 28c, thus increasing the capacity of the secondary battery. Furthermore, by joining the overlapping portion D to the electrode joints 27c, 28c, the tab assemblies 51, 56 of each electrode body 40 to the electrode joints 27c, 28c can be electrically connected via a single ultrasonic bonding process. Therefore, the increase in assembly time required for the secondary battery can be suppressed, and a higher capacity secondary battery can be achieved.
[0079] [Modifications of the Second Embodiment]
[0080] Next, a modified example of the secondary battery according to the second embodiment will be described. For example... Figure 13 and Figure 14As shown, in the modified secondary battery of the second embodiment, the electrode joint 28c has joint surfaces Mb1 and Mb2 on both sides. In the Y-axis direction, the electrode joint 28c is disposed between the tabs 56, 56 of the two electrode bodies 40, 40. The electrode joint 28c is disposed on the center line C of the two electrode bodies 40, 40 in the Y-axis direction. One of the two negative electrode tabs 56, 56 is ultrasonically bonded to the joint surface Mb1 at the joint point A, and the other is ultrasonically bonded to the joint surface Mb2 at the same joint point A. When the two negative electrode tabs 56, 56 are engaged with the electrode joint 28c, they are bent together with the electrode joint 28c along the end face of one of the electrode bodies 40. The same applies to the positive electrode side.
[0081] Furthermore, in this modified example, the positional relationship between the electrode joints 27c, 28c and the two electrode bodies 40, 40, and the position of the tabs 51, 56 of the electrode bodies 40 in the Y-axis direction are not particularly limited. For example... Figure 15 As shown, the electrode joint 28c can also be positioned in the Y-axis direction near the center of the two electrode bodies 40, 40 and on one side of the electrode body 40. Furthermore, the overlapping portions D of the tab assemblies 51, 56 of multiple electrode bodies 40 can be joined to the joint surfaces Mb1, Mb2 of the electrode joints 27c, 28c.
[0082] [Third Implementation Method]
[0083] Next, the secondary battery of the third embodiment will be described. Furthermore, the following description mainly focuses on structures that differ from the first and second embodiments, omitting descriptions of other structures. For example... Figure 16 As shown, the secondary battery of the third embodiment has three electrode bodies 40, 40, 40 inside the battery casing 10. The negative electrode tabs 56, 56, 56 of each of the three electrode bodies 40, 40, 40 are engaged with the electrode junction 28c in a state where they overlap the engagement surface Mb side of the second portion 28c2 of the electrode junction 28c. Furthermore, although not shown in the figure, the same applies to the positive electrode side. That is, in the secondary battery of the third embodiment, the tabs 51, 56 are also engaged with the second portions 27c2, 28c2 of the electrode junctions 27c, 28c in the overlapping portion D of the tabs 51, 56.
[0084] In the secondary battery of the third embodiment, the electrode body 40 is positioned in the Y-axis direction facing the end face of the central electrode body 40 and close to the side adjacent to the central electrode body 40. Here, the protruding lengths of the three negative electrode tab groups 56, 56, 56 relative to the electrode joint portion 28c differ, but the three negative electrode tab groups 56, 56, 56 have an overlapping portion D, which joins with the second portion 28c2 at a joining portion A above a predetermined area. Therefore, the joining state between the electrode joint portion 28c and the three negative electrode tab groups 56, 56, 56 is ensured. Furthermore, the protruding portion 56b of the three negative electrode tab groups 56, 56, 56 protruding from the electrode joint portion 28c can be appropriately cut off to place the electrode body 40 inside the battery case 10. Although not shown in the figure, the electrode joint portion 28c may also be positioned between two of the three negative electrode tab groups 56, 56, 56.
[0085] [Other Implementation Methods]
[0086] [1] In the above embodiment, a receiving space S is provided between the end face of the electrode body 40 in the X-axis direction and the mating surfaces Ma, Mb, Mb1, Mb2 of the electrode joints 27c, 28c, and the tab assemblies 51, 56 are accommodated in the receiving space S, but this embodiment is not limited to this embodiment. It is also possible that there is no receiving space between the end face of the electrode body in the X-axis direction and the mating surfaces of the electrode joints.
[0087] [2] In the above embodiment, each tab assembly 51, 56 is described as extending from one side of the electrode body 40 in the thickness direction (Y-axis direction) when viewed from each end face of the electrode body 40 along the winding axis (X-axis direction), but is not limited to this manner. For example, each tab assembly 51, 56 may extend from the center of the electrode body 40 in the thickness direction (Y-axis direction) when viewed from each end face of the electrode body 40 along the winding axis (X-axis direction).
[0088] [3] In the above embodiment, a method in which the secondary battery has a maximum of three electrode bodies 40 has been described, but it is not limited to this method. The number of electrode bodies may also be four or more. In this case, as long as the number of electrode joints of the current collector terminal is increased in accordance with the number of electrode bodies, or multiple tab groups are overlapped into triple or quadruple overlaps in accordance with the number of electrode bodies, and the tab groups and electrode joints are joined in the overlaps, the increase in the number of parts can be suppressed and the number of electrode bodies can be increased.
[0089] [4] In the above embodiment, the positive electrode tab group 51 and negative electrode tab group 56 of each electrode body 40 are described in the same position in the Z-axis direction, but this is not limited to this arrangement. The positive electrode tab group and 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 negative electrode tab group of each electrode body may also be in different positions in the Z-axis direction.
[0090] [5] In the above embodiment, the electrode body 40 was described as a wound body, but it is not limited to this method. The electrode body 40 can be constructed with a positive electrode tab group and a negative electrode tab group, and there is no particular limitation. Various structures used in general sealed secondary batteries can be adopted.
[0091] Furthermore, the structures disclosed in the above embodiments (including other embodiments, the same below) can be combined and applied with the structures disclosed in other embodiments as long as they do not contradict each other. 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.
[0092] Description of Reference Numerals
[0093] 1: Secondary battery
[0094] 11: Shell body (box)
[0095] 13: Sealing plate (lid)
[0096] 40: Electrode body
[0097] 42: Positive electrode tab
[0098] 47: Negative electrode tab
[0099] 51: Positive electrode tab assembly
[0100] 56: Negative electrode tab assembly
[0101] PS: Positive battery terminal (battery terminal)
[0102] NS: Negative battery terminal (battery terminal)
[0103] 27, 28: Collector terminals
[0104] 27b, 28b: Guiding section
[0105] 27c, 28c: Electrode junction
[0106] 27c1, 28c1: First part (electrode junction)
[0107] 27c2, 28c2: Second part (electrode junction)
[0108] 27d, 28d: Curved section
[0109] Ma, Mb: Joint surface
[0110] A: Joint area (joint part)
[0111] D: Overlapping part
[0112] S: Capacity space.
Claims
1. A secondary battery comprising a housing, a cover, flat electrode bodies, and battery terminals, wherein the housing has an opening, the cover is mounted on the opening of the housing, the electrode bodies are formed by stacking positive electrode material and negative electrode material with a separator in between, and the battery terminals are mounted on the cover. The aforementioned secondary battery is characterized by, The aforementioned electrode body comprises an electrode lug assembly formed by stacking the aforementioned positive electrode material and the aforementioned negative electrode material, and is housed within the aforementioned housing. The aforementioned tab assembly extends from the end face of the aforementioned electrode body in a second direction orthogonal to the thickness direction, i.e., the first direction. The aforementioned battery terminal has a guide portion disposed on an end face along the aforementioned second direction of the aforementioned electrode body, a plate-shaped electrode engagement portion extending from the aforementioned guide portion, and a curved portion between the aforementioned guide portion and the aforementioned electrode engagement portion. The aforementioned electrode junction has a mating surface at a position corresponding to the aforementioned tab assembly on at least one side of its surface. When viewed along the second direction, the aforementioned curved portion has a different upward position on a third direction orthogonal to the first direction than the aforementioned tab assembly of the electrode body. With the aforementioned tab assembly and the aforementioned electrode joint surface engaged, the aforementioned bending portion is bent so that the aforementioned electrode joint and the aforementioned tab assembly are facing the aforementioned end face of the aforementioned electrode body in the aforementioned second direction.
2. The secondary battery as described in claim 1, characterized in that, There is a receiving space between the aforementioned end face of the aforementioned electrode body in the aforementioned second direction and the aforementioned joint surface of the aforementioned electrode joint portion. The aforementioned tab assembly is housed within the aforementioned storage space.
3. The secondary battery as described in claim 1 or 2, characterized in that, It has multiple of the aforementioned electrode bodies, Each of the aforementioned electrode bodies has its respective tab assembly engaged with the aforementioned engagement surface of the aforementioned electrode joint.
4. The secondary battery as described in claim 3, characterized in that, The overlapping portion of the aforementioned electrode bodies having overlapping tabs in a direction orthogonal to the aforementioned engagement surface of the aforementioned electrode engagement portion. The aforementioned overlapping portion engages with the aforementioned engagement surface of the aforementioned electrode engagement portion.
Citation Information
Patent Citations
Connection member and rechargeable battery
WO2019140779A1