JP2012204004A - Connection structure and secondary battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure which can connect an electrode terminal and an external configuration while reducing the impact of contact resistance near the electrode of a battery.SOLUTION: The connection structure of an electrode terminal and a connection terminal connects an electrode terminal, having an internal connection member projecting inside the battery enclosure and being connected with a battery collector member and an external connection member assembled from the outside of the battery enclosure in contact with the internal connection member so as to be energized at a first contact part, electrically with a connection terminal connected with an external configuration. The connection terminal is connected nearer to the inside of the battery enclosure than the first contact part of the electrode terminal.

Description

  The present invention relates to a connection structure for connecting a battery electrode and a connection terminal connected to an external configuration, and a secondary battery system.

  The secondary battery is configured and used as an assembled battery in which a plurality of batteries are connected in series in actual use. In such an assembled battery, since the individual batteries have different capacities and self-discharge rates, control called cell balance is performed to equalize the charge rate of each secondary battery that repeats charge and discharge. In addition, the technique in the case of connecting a secondary battery in series is disclosed by patent document 1. FIG. In addition, there is a demand for a technique for measuring an accurate voltage for cell balance, and a technique for correcting an error in voltage measurement as in Patent Document 2 has been proposed.

JP 2006-294418 A JP 2009-070831 A

  Here, in order to perform cell balance, a connection terminal is connected to the electrode of the secondary battery, a voltmeter is connected to the connection terminal as an external configuration, and the voltage of the secondary battery is measured. Has been done to estimate. However, compared to secondary batteries used for stationary applications, secondary batteries used for mobile objects such as automobiles have a large charge / discharge current, so even a slight contact resistance near the electrodes of the secondary battery can actually be used. A large error occurs between the voltage of the secondary battery and the measured voltage.

For example, in the case of a secondary battery for stationary use, when the contact resistance is 0.3 mΩ and the charge / discharge current is 10 A, 0.3 mΩ × 10 A = 3 mV, and when measuring the voltage of the secondary battery, the contact resistance A voltage that is 3 mV lower than the actual voltage is measured. In contrast, in the case of a secondary battery for a moving body, even if the contact resistance is 0.3 mΩ, if the charge / discharge current is as large as 300 A, a voltage drop of 0.3 mΩ × 300 A = 90 mV occurs due to the contact resistance. . Therefore, when a secondary battery having a large charge / discharge current used for a moving body or the like is used in an assembled battery, a large difference occurs in the voltage of each secondary battery due to a slightly different value of contact resistance. Thus, since the actual voltage of each secondary battery is not known, there is a problem that cell balance (uniformization of the voltage of each secondary battery constituting the assembled battery) cannot be performed with sufficient accuracy.
In addition, when the contact resistance is fixed, it is not recognized as an obstacle in cell balance, but in fact, secondary batteries for mobile objects may be used in harsher environments than secondary batteries for stationary applications. In many cases, contact resistance changes due to the influence of corrosion, and the amount of change cannot be predicted in advance, which is a problem in performing cell balance.

  Accordingly, an object of the present invention is to provide a connection structure and a secondary battery system that can reduce the influence of contact resistance in the vicinity of an electrode of a secondary battery and connect the electrode terminal and an external configuration.

In order to achieve the above object, the present invention includes an internal connection member that protrudes into the battery casing and is connected to a battery current collector, and a first contact portion from the outside of the battery casing to the internal connection member. An external connection member assembled so as to be able to be energized, and an electrode terminal having a connection terminal connected to an external configuration, and the connection structure of the electrode terminal and the connection terminal electrically connected, The connection structure is characterized in that the connection terminal is connected to the inside of the battery casing from the first contact portion of the electrode terminal.
According to this configuration, the connection terminal is connected to the inside of the battery housing from the first contact portion where the external connection member and the internal connection member are in contact. For this reason, an external structure and a battery current collection member can be electrically connected through a connection terminal and an electrode terminal in the position which is not influenced by the contact resistance in a 1st contact part. For this reason, for example, when a voltmeter is connected as an external configuration, even when the charge / discharge current of the secondary battery is large, it is possible to reduce the influence of the voltage drop due to the connection resistance and measure the voltage inside the battery, It is possible to reduce an error between the actual voltage of the secondary battery and the measurement result of the voltage by the voltmeter as an external configuration.

In the connection structure according to the present invention, the connection terminal is connected to the external connection member.
According to this configuration, since the connection terminal is connected to the external connection member on the inner side of the battery housing than the first contact portion where the external connection member and the internal connection member are in contact with each other, the structure is simplified. be able to.

In the connection structure according to the present invention, the internal connection member is assembled with a connection portion connected to the external connection member, and in contact with the connection portion so that current can be passed through the second contact portion. An internal terminal connected to the member, wherein the connection terminal is connected to the internal terminal.
According to this configuration, the connection terminal is directly connected to the internal terminal inside the battery casing with respect to the second contact portion where the coupling portion and the internal terminal are in contact with each other in the internal connection member. Thereby, an external structure and a battery current collection member can be electrically connected through a connection terminal and an electrode terminal in the position which is not influenced by the contact resistance of both a 1st contact part and a 2nd contact part.

According to the present invention, in the connection structure, an insulator interposed between the battery casing and the electrode terminal, and a conductive portion disposed inside the insulator and protruding outside the battery casing. And the connection terminal is electrically connected to the conducting portion inside the insulator.
According to this configuration, the connection terminal is connected to the external configuration through the conductive portion disposed inside the insulator, so that the connection terminal is connected to the electrode terminal on the battery housing inner side to reduce the contact resistance. While further reducing, the insulator can be reliably insulated from other components and connected to the external components.

Moreover, the present invention is characterized in that, in the connection structure, the internal connection member includes a collar portion that is in surface contact with and electrically connected to the battery current collecting member.
According to this structure, the whole surface of a battery current collection member closely_contact | adheres to the collar part of an internal terminal. Therefore, the joint surface between the internal terminal and the battery current collecting member becomes large, and the contact resistance can be reduced.

  Moreover, this invention is a secondary battery system provided with the secondary battery which has the above-mentioned connection structure.

  ADVANTAGE OF THE INVENTION According to this invention, the connection structure and secondary battery system which can reduce the influence of the contact resistance of the electrode vicinity of a secondary battery and can connect an electrode terminal and an external structure can be provided.

It is a schematic external view of a secondary battery. It is a figure which shows the connection structure of the electrode terminal and connection terminal by a 1st Example. It is a figure which shows the connection structure of the electrode terminal and connection terminal by a 2nd Example. It is a figure which shows the connection structure of the electrode terminal and connection terminal by 3rd Example. It is a figure which shows the connection structure of the electrode terminal and connection terminal by a 4th Example. It is a figure which shows the outline | summary of a secondary battery system.

The secondary battery connection structure and secondary battery system of the present invention will be described below with reference to the drawings.
Example 1
FIG. 1 is a schematic external view of a secondary battery.
As shown in FIG. 1, the secondary battery 1 according to the present embodiment includes a battery case 2 that stores an electrolyte solution made of an organic material therein, and an electrode plate that is disposed in the battery case 2 and stacked. The laminated body 12 is provided.

The battery housing 2 is made of, for example, aluminum and includes a main body 2a having an opening and a lid 2b that closes the opening of the main body 2a. And the through-hole is formed in the cover part 2b, and the electrode terminal 4 which electrically connects the inside and the exterior of the battery housing | casing 2 to the said through-hole is provided. The electrode terminal 4 includes a positive terminal 4A and a negative terminal 4B. A sleeve-like insulator 3 is fitted into the through-hole of the lid 2 b, and the electrode terminal 4 is fitted to the insulator 3, thereby insulating the battery housing 2 from the electrode terminal 4. Is planned.
Moreover, the laminated body 12 includes a plurality of positive plates 18 and negative plates 20 stacked alternately in the stacking direction as electrode plates, a plurality of separators 21 disposed between the positive plates 18 and the negative plates 20, It has. In FIG. 1, the positive electrode plate 18, the negative electrode plate 20, and the separator 21 are displayed as having a sufficient thickness for easy viewing of the drawing, but all are configured in a sheet shape.

  A battery current collecting tab 19 (a battery current collecting tab 19A on the positive electrode side, a battery current collecting tab 19B on the negative electrode side; a battery current collecting tab 19B) is provided at each edge of the positive electrode plate 18 and the negative electrode plate 20 on the positive electrode terminal 4A and negative electrode terminal 4B side. Electric members) are arranged. Here, in the positive electrode plate 18 and the negative electrode plate 20, the battery current collecting tabs 19 </ b> A and 19 </ b> B are arranged so as to be biased to either side from the center of the edge corresponding to the positive electrode terminal 4 </ b> A or the negative electrode terminal 4 </ b> B, respectively. . The positive electrode plate 18 and the negative electrode plate 20 are laminated so that the battery current collecting tabs 19A and 19B do not overlap with each other on the different side from the edge center. The battery current collecting tab 19A of the positive electrode plate 18 is connected to the positive electrode terminal 4A, and the battery current collecting tab 19B of the negative electrode plate 20 is connected to the negative electrode terminal 4B.

  The separator 21 is for insulating the adjacent positive electrode plate 18 and negative electrode plate 20 and is, for example, a sheet-like resin microporous film made of polypropylene or the like. Note that at least one of the positive electrode plate 18 and the negative electrode plate 20 is sealed to the separator 21 with the battery current collecting tab 19A or the battery current collecting tab 19B protruding, so that the adjacent positive electrode plate 18 and negative electrode plate 20 are sealed. May be insulated from each other.

FIG. 2 is a diagram showing a connection structure of electrode terminals and connection terminals according to the first embodiment.
As shown in this figure, the electrode terminal 4 protrudes into the battery housing 2 and is connected to the internal connection member 11 connected to the battery current collecting tab 19 and from the outside of the battery housing 2 to the internal connection member 11. And the external connection member 12 assembled in contact with the first contact portion 21 so as to be energized. The internal connection member 11 includes a connecting portion 13 that is fitted to the insulator 3 and connected to the external connecting member 12, and an internal terminal that is assembled in contact with the connecting portion 13 so that the second contact portion 22 can be energized. 14.
In the internal connection member 11, the connecting portion 13 is a substantially cylindrical shape, and is a member in which an internal thread is formed on the inner peripheral surface. The internal terminal 14 has a shaft portion 14 a on which a male screw is formed, and a head portion 14 b provided at the base end of the shaft portion 14 a, and the shaft portion 14 a is connected to the connecting portion 13 inside the battery housing 1. By being screwed together, the portions of the female screw and the male screw are in contact with each other so as to be energized and assembled.
Then, the shaft portion 14a of the internal terminal 14 is inserted into the through hole formed in the battery current collecting tab 19 and is sandwiched between the head portion 14b and the end surface of the connecting portion 13, so that the battery current collecting tab 19 is The electrode terminal 14 is connected to the internal connection member 11.

The external connection member 12 has a shaft portion 12a and a head portion 12b provided at the proximal end of the shaft portion 12a. The shaft portion 12a is connected to the connecting portion 12 of the internal connection member 11 outside the battery housing 1. By being screwed together, the portions of the female screw and the male screw are in contact with each other so as to be energized and assembled.
The external power receiving or power transmission configuration is connected to the external connection member 12, whereby charging / discharging from the multilayer body 12 inside the battery housing 1 is possible.

The electrode terminal 4 is connected to a connection terminal 30 that is electrically connected to an external configuration (not shown) provided outside the secondary battery 1. As an external configuration, for example, as shown in FIG. 1, a voltmeter 60 is used, whereby the voltage between the electrode terminals 4 can be measured to measure the internal voltage of the secondary battery 1. And when comprised as an assembled battery, based on the measurement result with this voltmeter, the charge / discharge current between each single cell is adjusted using the cell balance circuit etc. which are not shown in figure.
Here, the connection terminal 30 is connected to the inner side of the battery housing 2 than the first contact portion 21 between the internal connection member 11 and the external connection member 12 in the battery terminal 4. Specifically, in the present embodiment, the connection terminal 30 has a through hole 30 a that is substantially equal to the outer diameter of the connecting portion 13. And the connection terminal 30 is connected to the connection part 13 via the 1st contact part 21 from the external connection member 12, and the connection part 13 from the inside by being fitted by the outer peripheral surface of the connection part 13. In the energization path, the battery housing 2 is connected to the inner side of the first contact portion 21.

  In this way, the connection terminal 30 is connected to the inner side of the battery housing 2 relative to the first contact portion 21 of the external connection member 12, so that the connection terminal 30 is not affected by the contact resistance in the first contact portion 21. The voltage can be measured from the terminal 4. As a result, even when the charge / discharge current of the secondary battery is large, it is possible to reduce the influence of the connection resistance and measure the battery voltage, so the error between the actual secondary battery voltage and the voltage measurement result. Can be reduced. As a result, the accuracy of voltage measurement of each secondary battery constituting the assembled battery can be improved using a cell balance circuit or the like (not shown), and control for keeping the voltage of each secondary battery constant is performed. Can do.

(Example 2)
FIG. 3 is a diagram showing a connection structure of electrode terminals and connection terminals according to the second embodiment.
In this embodiment, members that are the same as those used in the embodiments described above are given the same reference numerals, and descriptions thereof are omitted.
As shown in FIG. 3, in the connection structure of the present embodiment, the connection terminal 31 is connected to the electrode terminal 4 inside the battery casing 2 through the connection terminal opening opened in the lid 2 b of the battery casing 2. Has been. The connection terminal opening of the lid 2b is sealed with a shield 32 or the like.

  Here, the connection terminal 31 is connected to the battery terminal 4 on the innermost side of the battery housing 2 of the second contact portion 22 between the internal connection member 11 and the coupling portion 13. Specifically, in the present embodiment, the connection terminal 31 has a through hole 30 a that is substantially equal to the outer diameter of the shaft portion 14 a of the internal terminal 14. Further, the battery current collecting tab 19 has a through hole 19 a that is substantially equal to the outer diameter of the shaft portion 14 a of the internal terminal 14. The connection terminal 31 and the battery current collecting tab 19 are fitted to the outer peripheral surface of the shaft portion 14 a of the internal terminal 14 so that the connection terminal 31 is located below the battery current collecting tab 19. As a result, the battery current collecting tab 19 and the connection terminal 31 are in close contact with each other to form an energization path in which the battery current collecting tab 19 and the connection terminal 31 are directly connected.

  In this way, the connection terminal 31 is directly connected to the battery current collecting tab 19, so that the electrode terminal 4 is not affected by the contact resistance of the first contact portion 21 and the contact resistance of the second connection portion 22. The voltage can be measured from As a result, even when the charge / discharge current of the secondary battery is large, it is possible to reduce the influence of the connection resistance and measure the battery voltage, so the error between the actual secondary battery voltage and the voltage measurement result. Can be reduced. As a result, the accuracy of voltage measurement of each secondary battery constituting the assembled battery can be improved using a cell balance circuit or the like (not shown), and control for keeping the voltage of each secondary battery constant is performed. Can do.

(Example 3)
FIG. 4 is a diagram showing a connection structure of electrode terminals and connection terminals according to the third embodiment.
In this embodiment, members that are the same as those used in the embodiments described above are given the same reference numerals, and descriptions thereof are omitted.
As shown in FIG. 4, in the connection structure of the present embodiment, the insulator 40 is cylindrical and is interposed between the battery housing 2 and the electrode terminal 4, and the electrode terminal 4 is connected to the insulator 40. It is arranged in the center. In addition, inside the insulator 40, the conductive portion 50 is arranged on the outer peripheral side of the electrode terminal 4 so as to be insulated from the electrode terminal 4 by the inner peripheral portion of the insulator 40 and protrudes outside the battery housing 2. Have
Further, in the connection structure of the present embodiment, the connection terminal 23 is an annular member provided so as to be exposed on the end surface 40a of the insulator 40 inside the battery housing 2, and the outer edge portion 23a is connected to the conduction portion 50. While being integrally connected, the inner edge portion 23 b is in contact with the shaft portion 14 a of the internal terminal 14 of the internal terminal member 11.
Further, the surface of the connection terminal 23 exposed from the insulator 40 is in surface contact with the electrode current collecting tab 19 sandwiched between the head portion 14 b of the internal terminal 14.

  In this way, the connection terminal 23 is directly connected to the battery current collecting tab 19, so that a voltage is applied from the electrode terminal 4 without being affected by the contact resistance of both the first contact portion 21 and the second connection portion 22. Measurement can be performed, and an error in voltage measurement can be reduced as in the second embodiment. Further, in the connection structure of the present embodiment, the connection terminal 23 is connected to the external structure by the conductive portion 50 disposed inside the insulator 40, so that the insulation from the battery housing 2 and the like can be reliably achieved. On the other hand, it is not necessary to provide a separate sealing means for connection terminals as in the second embodiment, and the external configuration can be connected with a simple configuration.

Example 4
FIG. 5 is a diagram showing a connection structure of electrode terminals and connection terminals according to the fourth embodiment.
As shown in this figure, the electrode terminal 4 according to the fourth embodiment is different from the third embodiment in the configuration of the internal terminal 14. Specifically, in the through hole substantially equal to the outer diameter of the shaft portion 14a of the internal terminal 14 between the end surface 40a of the insulator 40 inside the battery housing 2 and the battery current collecting tab 19, the shaft portion 14a. And the surface of the collar portion 141 has a larger area than the entire surface of the battery current collecting tab 19, and the planar battery current collecting tab is provided. It is closely connected so as to cover the surface of 19. Accordingly, the entire surface of the battery current collecting tab 19 is in close contact with the collar portion 141 of the internal terminal 14. Therefore, the joint surface between the internal terminal 14 and the battery current collecting tab 19 is increased, and the contact resistance can be reduced. As a result, even when the charge / discharge current of the secondary battery is large, it is possible to reduce the influence of the connection resistance and measure the battery voltage, so the error between the actual secondary battery voltage and the voltage measurement result. Can be reduced.

(Example 5)
FIG. 6 is a diagram showing an outline of the secondary battery system.
As shown in FIG. 6, the assembled battery 100 including the secondary battery having the connection structure of Examples 1 to 4 is mounted on a car or the like. Then, by the cell balance control, the voltage of each secondary battery is maintained within an allowable voltage range, and the battery state monitoring device 200 that measures the voltage of each secondary battery outputs information on the voltage to the display unit 300. To do.
By such processing, it is possible to notify the user of the voltage value averaged by the cell balance of each of the plurality of secondary batteries constituting the assembled battery.

DESCRIPTION OF SYMBOLS 1 ... Secondary battery 2 ... Battery housing 3 ... Insulator 4 ... Electrode terminal 11 ... Internal connection member 12 ... External connection member 13 ... Connection part 14 ... Internal terminal 21 ... first contact portion 22 ... second contact portion 23, 30, 31 ... connection terminal 40 ... insulator 50 ... conduction portion 100 ... battery battery 141 ... Collar part 200 ... Battery state monitoring device 300 ... Display part

Claims (6)

An internal connection member that protrudes into the battery housing and is connected to the battery current collector, and an external connection member that is assembled from the outside of the battery housing so as to be in contact with the internal connection member at the first contact portion. And an electrode terminal having,
With a connection terminal connected to the external configuration,
A connection structure for electrically connecting the electrode terminal and the connection terminal,
The connection structure, wherein the connection terminal is connected to an inner side of the battery casing than the first contact portion of the electrode terminal.   The connection structure according to claim 1, wherein the connection terminal is connected to the external connection member. The internal connection member has a connection portion connected to the external connection member, and an internal terminal that is assembled in contact with the connection portion so as to be energized at the second contact portion and connected to the battery current collector member. And
The connection structure according to claim 1, wherein the connection terminal is connected to the internal terminal. An insulator interposed between the battery casing and the electrode terminal;
A conductive portion disposed inside the insulator and protruding outside the battery case;
The connection structure according to claim 1, wherein the connection terminal is electrically connected to the conduction portion inside the insulator. The connection structure according to any one of claims 1 to 4, wherein the internal connection member includes a collar portion that is in surface contact with and electrically connected to the battery current collecting member.   The secondary battery system provided with the secondary battery which has a connection structure as described in any one of Claims 1-5.

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