Secondary battery pack of embedded type of novel structure

Abstract

A secondary battery pack including a battery cell having first and second electrode terminals at a top thereof, an electrically insulative mounting member having an opening, through which the second terminal is exposed, the mounting member being mounted to a top of the cell, a protection circuit module (PCM) including a protection circuit board (PCB), having a protection circuit, loaded on the mounting member, a connection member (A) connected to the first terminal, and a connection member (B) connected to the second terminal, the PCB being provided with a through hole, through which the connection member (B) is exposed, and an insulative cap coupled to an upper end of the cell to surround the mounting member in which the connection members and the PCB are loaded on the mounting member, wherein the sum of a height of the PCM and a height of the cap is 3.0 mm or less.

Claims

1. A secondary battery pack comprising: a battery cell having an electrode assembly of a cathode/separator/anode structure disposed in a battery case together with an electrolyte in a sealed state, the battery cell having first and second electrode terminals formed at a top thereof; an electrically insulative mounting member having an opening, through which the second electrode terminal of the battery cell is exposed, the electrically insulative mounting member being mounted to a top of the battery cell; a protection circuit module (PCM) comprising a protection circuit board (PCB), having a protection circuit, loaded on the electrically insulative mounting member, a first connection member (A) connected to a first electrode terminal of the battery cell, and a second connection member (B) connected to the second electrode terminal of the battery cell via a safety element, the PCB being provided with a through hole, through which the second connection member (B) is exposed; and an insulative cap coupled to an upper end of the battery cell to surround the electrically insulative mounting member in a state in which the connection members and the protection circuit board are loaded on the electrically insulative mounting member, wherein a sum of a height of the PCM and a height of the insulative cap is 3.0 mm or less, wherein the second connection member (B) is coupled to a bottom of the PCB at the through hole, wherein the safety element is a positive temperature coefficient (PTC) element, wherein the PTC element comprises a PTC body, a PCM coupling part coupled to a top of the PTC body, and a battery cell coupling part coupled to a bottom of the PTC body, the PCM coupling part being coupled to the second connection member (B), and wherein the second electrode terminal is an anode terminal protruding from a middle of the top of the battery cell, and the first electrode terminal is a cathode terminal formed at the top of the battery cell excluding the anode terminal.

2. The secondary battery pack according to claim 1, wherein the insulative cap has a thickness of 0.4 mm or less.

3. The secondary battery pack according to claim 1, wherein the PCB has a thickness of 0.6 mm or less.

4. The secondary battery pack according to claim 1, wherein the battery case is a prismatic metal container.

5. The secondary battery pack according to claim 1, wherein the connection members are coupled to a bottom of the PCB using surface mount technology (SMT).

6. The secondary battery pack according to claim 1, wherein one end of the first connection member (A) is coupled to a bottom of the PCB in a state in which the end of the first connection member (A) extends longer than an outer circumference of the PCB such that the end of the first connection member (A) is exposed upward.

7. The secondary battery pack according to claim 1, further comprising an auxiliary mounting member having one end coupled to a bottom of the PCB and the other end coupled to the top of the battery cell such that the PCB is stably mounted to the battery cell.

8. The secondary battery pack according to claim 7, wherein the auxiliary mounting member is coupled to a position opposite to the first connection member (A).

9. The secondary battery pack according to claim 8, wherein the auxiliary mounting member is coupled to the bottom of the PCB in a state in which the auxiliary mounting member extends longer than an outer circumference of the PCB such that one end of the auxiliary mounting member is exposed upward.

10. The secondary battery pack according to claim 7, wherein the auxiliary mounting member is a nickel plate.

11. The secondary battery pack according to claim 1, wherein the insulative cap is coupled to a top of the battery case by bonding.

12. The secondary battery pack according to claim 1, wherein the battery cell is a lithium secondary battery cell.

13. The secondary battery pack according to claim 1, wherein the battery cell has an electrode assembly disposed in a battery case made of aluminum or an aluminum alloy together with an electrolyte in a sealed state.

Description

DESCRIPTION OF DRAWINGS

(1) The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is an exploded perspective view showing the upper end of a battery cell according to an embodiment of the present invention and an insulative cap, on which an insulative mounting member is loaded;

(3) FIG. 2 is a partially enlarged side view of FIG. 1;

(4) FIG. 3 is a partial perspective view showing a state in which the insulative mounting member is mounted to the upper end of the battery cell;

(5) FIG. 4 is a partial perspective view showing a state in which a protection circuit module (PCM) is mounted at the structure of FIG. 2;

(6) FIG. 5 is a partial perspective view showing a state in which the insulative cap is mounted at the structure of FIG. 4;

(7) FIG. 6 is a partial perspective view showing the upper end of a battery cell according to another embodiment of the present invention;

(8) FIG. 7 is a partial side view of FIG. 6;

(9) FIG. 8 is a front view showing the battery cell to which connection pins, which are used during a charging process to activate the battery cell, are coupled;

(10) FIG. 9 is an exploded perspective view showing the battery cell, an anodized part, and an insulation tape; and

(11) FIG. 10 is a partial perspective view showing the lower end of the battery cell.

DETAILED DESCRIPTION OF THE INVENTION

(12) Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted, however, that the scope of the present invention is not limited by the illustrated embodiments.

(13) FIG. 1 is an exploded perspective view showing the upper end of a battery cell according to an embodiment of the present invention and an insulative cap, on which an insulative mounting member is loaded, FIG. 2 is a partially enlarged side view of FIG. 1, FIG. 3 is a partial perspective view showing a state in which the insulative mounting member is mounted to the upper end of the battery cell, FIG. 4 is a partial perspective view showing a state in which a protection circuit module (PCM) is mounted at the structure of FIG. 2, and FIG. 5 is a partial perspective view showing a state in which the insulative cap is mounted at the structure of FIG. 4.

(14) Referring to these drawings, a secondary battery pack 100 is configured to have a structure including a battery cell 110, an electrically insulative mounting member 120 mounted to the top of the battery cell 110, a protection circuit module (PCM) 130, and an insulative cap 140 mounted to the upper end of the battery cell 110 while surrounding the insulative mounting member 120.

(15) The battery cell 110 is configured to have a structure in which an electrode assembly of a cathode/separator/anode structure is mounted in a battery case 150 made of aluminum together with an electrolyte in a sealed state, an anode terminal 111 protrudes from the middle of the top of the battery cell 110, and a cathode terminal 112 is formed at the top of the battery cell 110 excluding the anode terminal 111.

(16) The electrically insulative mounting member 120 is provided with an opening 121, through which the anode terminal 111 of the battery cell 110 is exposed.

(17) The PCM 130 includes a protection circuit board (PCB) 133 loaded on the insulative mounting member 120, the PCB 133 having a protection circuit, a connection member 132 connected to the cathode terminal 112, and a connection member 136 connected to the anode terminal 111 via a positive temperature coefficient (PTC) element 134. The PCB 133 is provided with a through hole 137, through which the connection member 136 is exposed.

(18) The connection member 136 is coupled to the bottom of the through hole 137 of the PCB 133.

(19) Referring to FIG. 2, the PTC element 134 includes a PTC body 1341, a PCM coupling part 1342 coupled to the top of the PTC body 1341, and a battery cell coupling part 1343 coupled to the bottom of the PTC body 1341. The PCM coupling part 1342 is coupled to the connection member 136 through the through hole 137.

(20) Meanwhile, one end of the connection member 132 is coupled to the bottom of the PCB 133 by surface mount technology (SMT) in a state in which the end of the connection member 132 extends longer than the outer circumference of the PCB 133 such that the end of the connection member 132 is exposed upward.

(21) An auxiliary mounting member 135, formed of a nickel plate, having one end coupled to the bottom of the PCB 133 and the other end coupled to the top of the battery cell 110 is provided such that the PCB 133 can be stably mounted to the battery cell 110. The auxiliary mounting member 135 is coupled to a position opposite to the connection member 132.

(22) The insulative cap 140 is made of an electrically insulation material. The electrically insulative cap 140 is formed to surround the insulative mounting member 120 in a state in which the connection members 132 and 136 and the protection circuit board 133 are loaded on the electrically insulative cap 140.

(23) Also, referring to FIGS. 4 and 5, the insulative cap 140 is coupled to the top of the battery case by bonding. The insulative cap 140 has a thickness w of about 0.3 to 0.4 mm, and the PCB 133 has a thickness W of about 0.4 to 0.6 mm. As a result, the sum H of a height of the PCM 130 and a height of the insulative cap 140 is 3.0 mm or less.

(24) In the secondary battery pack 100 according to the present invention, therefore, the connection member 136, exposed through the through hole 137 of the PCB 133, is electrically connected to the anode terminal 111 of the battery cell 110 via the PTC element 134 from the above, and the connection member 132 is electrically connected to the cathode terminal 112 of the battery cell 110, in a state in which the PCM 130 is loaded on the insulative mounting member 120. Consequently, electrical connection is achieved using a simple connection method. Also, the sum of the height of the PCM 130 and the height of the insulative cap 140 is 3 mm or less. Consequently, it is possible to manufacture a secondary battery pack having higher energy density than other secondary battery packs having the same standard.

(25) FIG. 6 is a partial perspective view showing the upper end of a battery cell according to another embodiment of the present invention, FIG. 7 is a partially enlarged side view of FIG. 6, and FIG. 8 is a front view showing the battery cell to which connection pins, which are used during a charging process to activate the battery cell, are coupled.

(26) Referring to these drawings, a battery cell 110 having an electrode assembly disposed in a battery case 150 made of aluminum in a sealed state is manufactured as follows. First, the entire surface of the battery case 150 is anodized (155) (see FIG. 9) in a state in which an uncoated margin section 151 having a length h of about 3 mm is provided downward from the outer circumference of the upper end of the battery case 150 and a connection opening section 162, to which charge pins 160 and 161 used to activate the battery cell 110 are connected, is formed at the bottom 159 of the battery case 150.

(27) Subsequently, the electrode assembly is mounted in the battery case 150, a cap plate 152 is connected to the open upper end of the battery case 150 by laser welding, an electrolyte is injected through an electrolyte injection port 153 of the cap plate 152, and the battery cell is activated. Subsequently, the electrolyte is replenished, and then the electrolyte injection port 153 is sealed.

(28) At this time, the uncoated margin section 151 is formed by anodizing the battery case 150 in a state in which an insulation material (not shown) is applied to the battery case 150 and removing the insulation material.

(29) Also, the laser welding is carried out along the outer circumference of the battery cell 110 above the cap plate 152 (see an arrow shown in FIG. 6), and therefore, it is possible to easily perform the laser welding of the cap assembly.

(30) FIG. 9 is an exploded perspective view showing the battery cell, an anodized part, and an insulation tape, and FIG. 10 is a partial perspective view showing the lower end of the battery cell.

(31) Referring to these drawings together with FIGS. 6 to 8, the connection opening section 162 is formed in a quadrangular shape in plan. Alternatively, the connection opening section 162 may be formed in various shapes in plan.

(32) Also, the connection opening section 162 is formed by anodizing (155) the battery case 150 in a state in which an insulation material (not shown) is applied to a portion of the bottom of the battery case 150 and removing the insulation material.

(33) After the step of replenishing the electrolyte and sealing the electrolyte injection port, the connection opening section 162 is sealed using an insulation tape 165.

(34) Consequently, it is possible to easily achieve the connection of the charge pins by the provision of the connection opening section 162.

(35) Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.