JP2016085916A - Secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery having a configuration capable of securing a state of electrifying respective battery cells even when a connection failure has occurred at part of a connection section.SOLUTION: A secondary battery comprises a plurality of battery cells 13A, 13B having ends at which electrode exposure sections 11, 12 are provided. The secondary battery comprises: a collector terminal that is electrically connected to each of the electrode exposure sections 11, 12 of the plurality of battery cells 13A, 13B and is electrically connected to an external terminal; and a connection section 30 for electrically connecting the plurality of electrode exposure sections 11, 12 at positions of the electrode exposure sections 11, 12 that differ from those of the collector terminal.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a structure of a secondary battery.

  A typical secondary battery includes a battery cell (winding electrode body) inside a casing, and a positive electrode core exposed portion and a negative electrode core exposed portion are provided at both ends of the battery cell. A positive electrode current collector terminal is electrically connected to the exposed portion of the positive electrode core, and the positive electrode current collector terminal is electrically connected to the positive electrode external terminal. Similarly, the negative electrode current collector terminal is electrically connected to the negative electrode core exposed portion, and the negative electrode current collector terminal is electrically connected to the negative electrode external terminal. Secondary batteries having such a configuration are disclosed in Japanese Patent Application Laid-Open No. 2003-346878 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2012-160425 (Patent Document 2).

JP 2003-346878 A JP 2012-160425 A

  In recent years, due to the increase in capacity of secondary batteries, a plurality of battery cells have been accommodated inside the casing, and adjacent positive electrode core exposed portions are connected to the positive electrode current collector terminals, and similarly, A configuration in which the core exposed portions are connected to the negative electrode current collecting terminal is employed.

  However, when an external load such as vibration or shock is input to the secondary battery, there is a concern that a load is applied to the connection portion between the positive electrode current collector terminal and the positive electrode core exposed portion, causing a connection failure in the connection portion. The Similarly, there is a concern that a load is applied to the connection portion between the negative electrode current collecting terminal and the negative electrode core exposed portion, causing a connection failure in the connection portion.

  When a connection failure occurs in a part of the connection portion, the battery cell in which no current flows flows into a high energy state without discharging electricity. Moreover, since the capacity | capacitance of a secondary battery will fall remarkably when a contact failure arises, there is a concern that a part of battery cell may be in an overcharge state.

  The present invention has been made in view of the above problems, and includes a configuration capable of ensuring the energized state of each battery cell even when a connection failure occurs in a part of the connection portion. An object is to provide a secondary battery.

  In this secondary battery, a secondary battery including a plurality of battery cells each provided with an electrode exposed portion at an end thereof, and electrically connected to each of the electrode exposed portions of the plurality of battery cells, A current collecting terminal electrically connected to an external terminal, and a connection portion for electrically connecting the plurality of electrode exposed portions to the electrode exposed portion at a position different from the current collecting terminal.

  In this way, by providing a connection portion that electrically connects the plurality of electrode exposed portions, at a position different from the collector electrode electrically connected to each of the electrode exposed portions of the plurality of battery cells, When an external load is applied to the secondary battery, a plurality of battery cells are electrically connected by the connecting portion even if a contact failure occurs in a part of the collector electrode and the electrode exposed portion. Therefore, it can be avoided that no current flows through the battery cell. As a result, the secondary battery may be in a high energy state without discharging electricity, or the capacity as a secondary battery in which contact failure has occurred is significantly reduced, and some battery cells are overcharged. Can be avoided.

  According to this secondary battery, it is possible to provide a secondary battery having a configuration capable of ensuring the energization state of each battery cell even when a connection failure occurs in a part of the connection portion. And

3 is a plan view showing the secondary battery in the first embodiment. FIG. FIG. 3 is a longitudinal sectional view showing the secondary battery in the first embodiment. It is arrow sectional drawing along the III-III line in FIG. 4 is a first perspective view showing only a plurality of battery cells in Embodiment 1. FIG. FIG. 4 is a second perspective view showing only a plurality of battery cells in the first embodiment. 3 is a diagram illustrating an electrical circuit configuration of the secondary battery according to Embodiment 1. FIG. FIG. 3 is a diagram corresponding to a cross section taken along line III-III in FIG. 2 of the secondary battery in the second embodiment. 6 is a perspective view showing a configuration of a current collecting terminal in Embodiment 2. FIG. 6 is a first partial perspective view showing only a plurality of battery cells in Embodiment 2. FIG. 6 is a second partial perspective view showing only a plurality of battery cells in Embodiment 2. FIG. 6 is a front view of an auxiliary terminal in Embodiment 2. FIG. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 11. FIG. 10 is a front view of another auxiliary terminal in the second embodiment. FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. 13. FIG. 4 is a diagram corresponding to a cross section taken along line III-III in FIG. 2 of the secondary battery in the third embodiment.

  Each embodiment will be described below with reference to the drawings. When referring to the number, amount, etc., the scope of the present invention is not necessarily limited to the number, amount, etc., unless otherwise specified. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated. It is planned from the beginning to use the structures in the embodiments in appropriate combinations. In the drawings, the actual dimensional ratios are not described, and some ratios are described in order to facilitate understanding of the structure.

(Embodiment 1: Secondary battery 100)
With reference to FIGS. 1-6, the secondary battery 100 in this Embodiment is demonstrated. 1 is a plan view showing the secondary battery 100, FIG. 2 is a longitudinal sectional view showing the secondary battery 100, FIG. 3 is a sectional view taken along the line III-III in FIG. 5 is a first and second perspective view showing only the plurality of battery cells 13A and 13B, and FIG. 6 is a diagram showing an electrical circuit configuration of the secondary battery 100. As shown in FIG.

  Referring to FIG. 1 and FIG. 2, the secondary battery 100 includes an outer package 10, battery cells 13 </ b> A and 13 </ b> B, a positive external terminal 20, a positive current collector terminal 50, a negative external terminal 24, and a negative current collector. A terminal 51 is provided. The exterior body 10 includes a bottomed cylindrical housing portion 15 and a sealing plate 25. The exterior body 10 accommodates the battery cells 13A and 13B inside. The positive external terminal 20 and the negative external terminal 24 are attached to the sealing plate 25.

  Battery cells 13A and 13B have a positive electrode core body, a negative electrode core body, and a separator (all not shown), and the positive electrode core body and the negative electrode core body are wound through the separator. A positive electrode core exposed portion 11 and a negative electrode core exposed portion 12 are provided at both ends of the battery cells 13A and 13B, respectively.

  The positive electrode core exposed portion 11 is electrically connected to the positive electrode external terminal 20 via the positive electrode current collecting terminal 50. The negative electrode core exposed part 12 is electrically connected to the negative electrode external terminal 24 via the negative electrode current collecting terminal 51.

  As shown in FIG. 3, the positive electrode current collecting terminal 50 has a concave shape that sandwiches the battery cells 13A and 13B from both side surfaces, and the positive electrode core exposed portion 11 of the battery cell 13A and the positive electrode core body of the battery cell 13B. The exposed portion 11 is shaped so as to be in contact with the outside. The configuration of the negative electrode current collector terminal 51 is the same as that of the positive electrode current collector terminal 50, has a concave shape that sandwiches the battery cells 13A and 13B from both side surfaces, and the negative electrode core exposed portion 12 of the battery cell 13A and the battery cell 13B. The negative electrode core exposed portions 12 are formed so as to be in contact with each other from the outside.

  Furthermore, as shown in FIG. 4, a connection portion 30 is provided for electrically connecting the positive electrode core exposed portion 11 of the battery cell 13A and the positive electrode core exposed portion 11 of the battery cell 13B. The connecting portion 30 is provided in a region different from a region where the positive electrode current collecting terminal 50 contacts the positive electrode core exposed portion 11 of the battery cell 13A and the positive electrode core exposed portion 11 of the battery cell 13B. In the present embodiment, connecting portion 30 is formed of a region where positive electrode core exposed portions 11 are electrically connected to each other. For example, the exposed portion is formed using ultrasonic welding, resistance welding, laser welding, or the like. The two are configured to be directly electrically connected to each other.

  As shown in FIG. 5, the connection portion 30 is similarly provided in the negative electrode core exposed portion 12 of the battery cell 13 </ b> A and the negative electrode core exposed portion 12 of the battery cell 13 </ b> B.

  Thus, in secondary battery 100 in the present embodiment, positive electrode current collector terminal 50 and negative electrode current collector terminal 51 that are electrically connected to each of the electrode exposed portions of a plurality of battery cells 13A and 13B are different. The connection part 30 which electrically places an electrode exposure part in the position is provided.

  Accordingly, even when an external load is applied to the secondary battery 100, for example, even when a poor contact portion occurs at the positive electrode current collector terminal 50 and a part of the positive electrode core exposed portion 11, FIG. As shown in FIG. 6, the battery cells 13A and 13B are maintained in the state where the battery cells 13A and 13B are electrically connected by the connecting portion 30 without being isolated from the electrical circuit. As a result, it can be avoided that no current flows through the battery cells 13A and 13B.

  Further, since the capacity of the secondary battery 100 does not change, when no current flows in one of the battery cells 13A and 13B, the secondary battery 100 does not discharge electricity and is in a high energy state when fully charged. Therefore, it is possible to avoid that the capacity of the secondary battery 100 in which contact failure has occurred is significantly reduced (capacity balance is lost), and the battery cells 13A and 13B through which current flows are overcharged. Become.

  Further, in a normal state where the contact between the current collecting terminal and the electrode exposed portion is ensured, and further, the contact at the connection portion 30 is also ensured, the number of places where current flows in and out of the battery cells 13A and 13B increases, thereby increasing resistance. The value is reduced, and it is possible to expect an improvement in battery performance during normal use.

(Embodiment 2: Secondary battery 100A)
Next, with reference to FIGS. 7 to 13, secondary battery 100 </ b> A in the present embodiment will be described. 7 is a diagram corresponding to the cross section taken along the line III-III in FIG. 2 of the secondary battery 100A, FIG. 8 is a perspective view showing the configuration of the positive electrode current collector terminal 50A, and FIGS. First and second partial perspective views showing only the plurality of battery cells 13A and 13B, FIG. 11 is a front view of the auxiliary terminal 30A, FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. FIG. 14 is a front view of another auxiliary terminal 30B, and FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG.

  The difference between the secondary battery 100A in the present embodiment and the secondary battery 100 is the difference in the shapes of the positive electrode core exposed portion 11 and the negative electrode core exposed portion 12 of the battery cells 23A and 23B. The configuration of is the same. Therefore, below, it demonstrates centering on the difference in the shape of the positive electrode core exposure part 11. FIG. Further, since the same applies to the negative electrode core exposed portion 12, the positive electrode core exposed portion 11 side will be mainly described.

  7 to 9, battery cells 23A and 23B in the present embodiment have the same basic configuration as battery cells 13A and 13B described above, and the positive electrode core and the negative electrode core are wound with a separator interposed therebetween. Although the wound body is configured, the positive electrode core exposed portion 11 has a form in which the central region is crushed inward. Similarly, the negative electrode core exposed portion 12 has a form in which the central region is crushed inward.

  As shown in FIG. 7 and FIG. 8, the positive electrode current collecting terminal 50A has a concave shape that sandwiches the battery cells 23A and 23B from both side surfaces, but the tip part is the positive electrode core exposed portion 11 of the battery cell 23A. And, it has the form bent inside so that each center area | region of the positive electrode core body exposure part 11 of the battery cell 23B can contact from the outside. The configuration of the negative electrode current collector terminal 51A is the same as that of the positive electrode current collector terminal 50A.

  Further, as shown in FIGS. 7 and 9 to 12, an auxiliary terminal 30A as a connecting portion for electrically connecting the positive electrode core exposed portion 11 of the battery cell 23A and the positive electrode core exposed portion 11 of the battery cell 23B is provided. Is provided. The auxiliary terminal 30A is provided in a region different from a region where the positive electrode current collecting terminal 50A is in contact with the positive electrode core exposed portion 11 of the battery cell 23A and the positive electrode core exposed portion 11 of the battery cell 23B.

  In the present embodiment, the auxiliary terminal 30A is mounted in a space A1 formed between the positive electrode core exposed portions 11 and has a cross-sectional shape that follows the cross-sectional shape of the space A1, and is substantially in cross-sectional shape. It is molded into a V shape. The shape of the auxiliary terminal 30A is not limited to this shape, and an auxiliary terminal 30B having a substantially U-shaped cross section may be used as shown in FIGS.

  The auxiliary terminal 30A can be made of any material as long as it has conductivity. However, in battery cells, an aluminum material is usually used for the positive electrode core, and the negative electrode core is used. Since copper is used for the body, these materials may be used. The plate thickness is not particularly limited, and a thin material such as a foil material or a plate material of about several mm may be used.

  Thus, by adopting the shape along the cross-sectional shape of the space A1 for the auxiliary terminal 30A, a part of the space A1 formed between the positive electrode core exposed portions 11 can be filled, and the battery cell 23A, The battery cells 23A and 23B can be electrically connected to each other without applying an excessive force to 23B. For example, ultrasonic welding, resistance welding, or laser welding is used to connect the auxiliary terminal 30A to the positive electrode core exposed portion 11 and the negative electrode core exposed portion 12.

  As described above, also in secondary battery 100A in the present embodiment, the same operational effects as in secondary battery 100 in the first embodiment can be obtained.

(Embodiment 3: Secondary battery 100B)
Next, with reference to FIG. 15, the secondary battery 100B in the present embodiment will be described. FIG. 15 is a diagram corresponding to a cross section taken along line III-III in FIG. 2 of secondary battery 100B.

  The difference between secondary battery 100B and secondary battery 100A in the present embodiment is the number of battery cells. In the present embodiment, a configuration in which three battery cells 23A, 23B, and 23C are used is shown. Since the shapes of the positive electrode core exposed portion 11 and the negative electrode core exposed portion 12 are the same, the configuration of the positive electrode core exposed portion 11 will be mainly described.

  Referring to FIG. 14, in secondary battery 100B in the present embodiment, each positive electrode core body exposed portion 11 of battery cells 23A, 23B, and 23C is electrically connected by a positive electrode current collecting terminal 50B. Further, an auxiliary terminal 30A is disposed in a space A1 between the positive electrode core exposed portion 11 of the battery cell 23A and the positive electrode core exposed portion 11 of the battery cell 23B, and the positive electrode core exposed portion 11 of the battery cell 23B and the battery. The auxiliary terminal 30A is also arranged in the space A2 between the positive electrode core exposed portion 11 of the cell 23C.

  Thus, even when three battery cells 23A, 23B, and 23C are used, it is possible to obtain the same operational effects as those of secondary batteries 100 and 100A in the first and second embodiments.

  In each of the above embodiments, a configuration in which a connection portion (auxiliary terminal) is provided in any region of the positive electrode core exposed portion 11 and the negative electrode core exposed portion 12 is employed. You may employ | adopt the structure which provides a connection part (auxiliary terminal) only in a core exposure part. Moreover, although the number of battery cells has been described in the case of using two in the first and second embodiments and three in the third embodiment, the number of battery cells may be four or more.

  In addition, as an example of the battery cell, a battery cell including a positive electrode core body, a negative electrode core body, and a wound body around which a separator is wound is disclosed, but a positive electrode core body exposed portion and a negative electrode core body exposed portion are disposed at both ends. Any form of battery cell may be used as long as it has a battery cell.

  As mentioned above, although embodiment based on this invention was described, the content disclosed this time is an illustration and restrictive at no points. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 10 exterior body, 11 positive electrode core exposed part, 12 negative electrode core exposed part, 13A, 13B, 23A, 23B battery cell, 15 accommodating part, 20 positive electrode external terminal, 23A, 23B, 23C battery cell, 24 negative electrode external terminal, 25 Sealing plate, 30 connection part, 30A, 30B Auxiliary terminal, 50, 50A Positive current collecting terminal, 51, 51A Negative current collecting terminal, 100, 100A, 100B Secondary battery.

Claims (4)

A secondary battery comprising a plurality of battery cells each provided with an electrode exposed portion at an end,
A current collecting terminal electrically connected to each of the electrode exposed portions of the plurality of battery cells and electrically connected to an external terminal;
A connection part that electrically connects the plurality of electrode exposure parts at a position different from the current collector terminal with respect to the electrode exposure part,
A secondary battery comprising: The battery cell is a wound electrode body in which a positive electrode core body, a separator, and a negative electrode core body are wound, and a positive electrode core exposed portion is provided at one end of the wound electrode body, and the wound electrode A negative electrode core exposed portion is provided at the other end of the body,
The current collecting terminal is
A positive electrode current collector terminal electrically connected to each of the plurality of positive electrode core exposed portions, and electrically connected to an external positive electrode terminal;
A negative current collector terminal electrically connected to each of the plurality of negative electrode core exposed portions and electrically connected to an external negative electrode terminal,
The connecting portion is
A positive electrode connecting portion that electrically connects the plurality of positive electrode core exposed portions at a position different from the positive electrode current collecting terminal with respect to the positive electrode core exposed portion,
A negative electrode connecting portion for electrically connecting a plurality of the negative electrode core exposed portions at a position different from the negative electrode current collecting terminal with respect to the negative electrode core exposed portion,
The secondary battery according to claim 1.   The secondary battery according to claim 1, wherein the connection portion is configured from a region in which the plurality of electrode exposed portions are electrically connected to each other.   The secondary battery according to claim 1, wherein the connection portion is configured by providing an auxiliary terminal between the plurality of electrode exposed portions.

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