JPH0538535Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention uses a bobbin-type non-aqueous power generation element that has a cylindrical negative electrode arranged inside a hollow cylindrical positive electrode mixture with a separator in between. It relates to electrolyte batteries.

<Prior art> In this type of battery, for example, a bobbin-type lithium battery, a cylindrical lithium negative electrode is placed in the center of the battery can, and a positive electrode mixture is placed on the outside of this negative electrode with a separator interposed therebetween. An insulating gasket is compressed between the can opening and a terminal plate provided in the opening, and the negative electrode and positive electrode mixture are electrically connected to the terminal plate and the battery can, respectively.

Conventionally, when connecting the negative electrode and the terminal plate in this way, for example, as shown in FIG. At the same time, the other end of the lead terminal 2 is welded to a sealing plate or a terminal plate located at the opening of the battery can. Another method is also used in which the current collector and the lead terminal are constructed separately, one end of the lead terminal is welded to the current collector, and then crimped onto the inner periphery of the lithium negative electrode.

<Problems to be solved by the invention> However, this type of bobbin-type lithium battery, for example, has the following problems.

That is, it is desirable that the plate thickness t (see Figure 3) of the cylindrical lithium 11 be determined based on the capacity that will be completely consumed at the end of discharge, in relation to the cost of the lithium used and the amount of electrolyte that can be filled in the battery. However, in this case, due to non-uniformity of discharge on the lithium negative electrode surface at the end of discharge, the lithium on the current collector fixed surface may be consumed early, and the relationship between the lithium negative electrode 11 and the current collector 2a may deteriorate. There is a problem in that poor contact occurs and the discharge performance of the battery deteriorates.
In order to prevent such poor contact, it is possible to increase the capacity of the lithium negative electrode 11 and increase its plate thickness, but in this case, not only does the cost increase due to the increased lithium capacity, but also the necessary Since the battery cannot be filled with a sufficient amount of electrolyte, the discharge capacity will decrease.

<Means for solving the problem> The bobbin type non-aqueous electrolyte battery of this invention has a power generating element in which a cylindrical negative electrode is placed inside a hollow cylindrical positive electrode mixture with a separator interposed therebetween, and is housed in a battery can. In addition to being housed, a current collector for taking out current is fixed to the inner peripheral surface of the negative electrode, and the thickness of the negative electrode is made thicker at the part where the current collector is fixed than at other parts.

<Function> By using the above means, the portion of the negative electrode fixed to the current collector remains unconsumed even at the end of discharge, and poor contact between the negative electrode and the current collector (or lead terminal) can be reliably prevented. can.

<Example> An example in which this invention is applied to a bobbin type lithium battery will be described below.

In FIG. 1A, a convex portion 1b having a height h of about 0.3 mm is formed on the inner peripheral surface 1a of the cylindrical lithium negative electrode 1 over the entire inner circumference. This convex part 1
A current collector 2a for taking out current at one end of the lead terminal 2 is crimped to b. Here, if the lead terminal 2 and the current collector 2a are separate bodies, the current collector 2a is spot welded to one end of the lead terminal 2 and crimped to the convex portion 1b on the inner surface of the lithium negative electrode. In addition, when both are integrated, the wide portion at one end of the lead terminal 2 is used as a current collector 2a, and this current collector 2a is crimped to the convex portion 1b. still,
The size of the convex portion 1b in the vertical direction in the figure may be approximately the same as the width in the vertical direction in the figure of the current collector 2a that is crimped onto the convex portion 1b.

As shown in FIG. 1B, inside the bottomed cylindrical battery can 3 made of stainless steel, a hollow cylindrical positive electrode mixture 4 containing carbon fluoride, manganese dioxide, etc. as an active material, and a polypropylene After storing the separator 5 made of non-woven fabric and inserting the cylindrical lithium negative electrode 1 made above into the hollow part of the separator, a non-aqueous electrolyte was injected and the other end of the lead terminal 2 was led out from the inner peripheral surface of the negative electrode. is spot welded to a thin stainless steel sealing plate 7 placed in the opening of the battery can, and a stainless steel terminal plate 6 is placed on the outer side of the battery on the sealing plate 7, and a composite is formed between these and the opening of the battery can. A bobbin-type lithium battery as shown is assembled by supporting the insulating gasket 8 made of resin under pressure.

FIG. 2 shows another example of the lithium negative electrode according to the present invention. In this lithium negative electrode 10, the current collector 2
The convex portion 10b is provided only on the inner circumferential surface where a is crimped, and the convex portion 10b is the same as the above embodiment except that the size of the convex portion 10b is approximately the same as that of the current collector 2a. be.

<Effects of the invention> As described above, according to the bobbin type non-aqueous electrolyte battery of this invention, there is an increase in cost due to the extra thickness of the negative electrode, and a decrease in performance due to a decrease in the amount of electrolyte filled. Therefore, it is possible to prevent poor contact between the negative electrode and the current collector at the end of discharge, thereby improving battery discharge performance.

[Brief explanation of the drawing]

FIG. 1A is a sectional view showing the negative electrode used in the embodiment of this invention, FIG. 1B is a sectional view of the battery of the embodiment,
FIG. 2 is a sectional view showing another example of the negative electrode, and FIG. 3 is a sectional view of a negative electrode used in a conventional battery. 1, 10, 11... Lithium negative electrode, 2... Lead terminal, 2a... Current collector.

Claims (1)

[Claims for Utility Model Registration] 1. A power generation element in which a cylindrical negative electrode is arranged inside a hollow cylindrical positive electrode mixture via a separator is housed in a battery can, and a power generation element is installed on the inner peripheral surface of the negative electrode for current extraction. A bobbin type non-aqueous electrolyte battery comprising a fixed current collector, the negative electrode being thicker in the part to which the current collector is fixed than in other parts. 2 Utility model registration claim 1, characterized in that the current collector fixing portion of the inner circumference of the negative electrode is a convex portion
The bobbin type non-aqueous electrolyte battery described in .